Static electricity and micro-pollution protection for the electronics industry – Gloves

  • Classification and introduction of dust-free gloves
  • Features of dust-free gloves
  • The role of dust-free gloves
  • Comparison of the performance of dust-free gloves
  • Application environment of dust-free gloves
  • Dust free gloves production process
  • Dust-free glove performance test equipment display
  • Test methods for dust-free performance of dust-free gloves

Classification and introduction of dust-free gloves

The gloves commonly used in cleanrooms are divided into: nitrile gloves, latex gloves and PVC gloves.

I. Nitrile gloves

  1.  Nitrile gloves are made of 100% synthetic nitrile rubber, processed through a special production process.
    Nitrile gloves are made of 100% synthetic nitrile rubber, processed through a special production process.
  2. Nitrile gloves are classified as:
    1. 9-inch nitrile glove
      1. 9-inch white nitrile glove
      2. 9-inch blue nitrile glove
    2. 12-inch nitrile glove
      1. 12-inch class 100 nitrile glove
      2. 12-inch class 1000 nitrile glove
      3. 12-inch powder-free nitrile glove
        1. 12-inch white powder-free nitrile glove
        2. 12-inch blue powder-free nitrile glove
  3. Nitrile gloves features.
    • Comfortable to wear, long time wear will not cause skin tautness, conducive to blood circulation.
    • Does not contain amino compounds and other harmful substances, will not cause allergies.
    • Short degradation time, easy to handle, good for environmental protection.
    • Good tensile strength, puncture resistance, not easy to break.
    • Good airtightness, effectively preventing dust from escaping to the outside.
    • Excellent chemical resistance, resistant to a certain degree of acidity and alkalinity, resistant to hydrocarbon attack, not easy to break.
    • Silicone-free composition, with certain antistatic properties, suitable for the production needs of the electronics industry.
    • Low chemical residues on the surface, low ionic content, low particle content, suitable for strict dust-free environments.

II. Latex gloves

  1. Latex gloves use natural latex as raw material and are processed through a special process.
    Latex gloves
  2. Latex gloves are classified as:
    1. 9-inch
      1. 9-inch gloss-finish latex glove
      2. 9-inch rough-finish latex glove
    2. 12-inch latex glove
      1. 12-inch glossy latex glove
      2. 12-inch non-glossy latex glove
  3. Characteristics of latex gloves.
    • 100% natural latex, good elasticity, long time wearing will cause allergy to some people.
    • Comfortable to wear, free from oxidising agents, grease and salts.
    • Strong tensile strength, puncture resistance, not easy to break.
    • Excellent chemical resistance, resistant to certain acids and alkalis, resistant to some organic solvents, such as acetone.
    • Short degradation time, easy to handle, good for the environment.

III.PVC gloves

  1. PVC gloves use polyvinyl chloride as the main raw material.
    PVC gloves use polyvinyl chloride as the main raw material.
  2. PVC gloves are classified as follows.
    1. 9-inch PVC glove
      1. 9-inch normal PVC glove
      2. 9-inch thin PVC glove
    2. 12-inch PVC glove
      1. 12-inch normal PVC glove
      2. 12-inch thin PVC glove
  3. Characteristics of PVC gloves.
    • Low price, pigments can be added, bright colours.
    • Comfortable to wear.
    • Good airtightness, effectively prevents dust from emanating to the outside.
    • Less elastic, easy to break (compared with latex gloves, nitrile gloves).
    • PVC gloves are not resistant to corrosion and contact with corrosive substances is prohibited.

The role of dust-free gloves

People are seen as the largest source of contaminants within the clean room, with people contaminating up to 80% of the clean room so operators must ensure the cleanliness of the environment by wearing clean suits, gloves etc. As an item that comes into direct contact with the product, gloves are the most critical part of the entire protection system, ensuring that people do not contaminate the cleanliness of the key production process areas in the controlled environment, but also that they do not directly cause secondary contamination to the product.

The main micro-pollutants controlled in a clean room are: particles, ions, silicone oil etc. Different gloves are selected according to different requirements, the higher the clean room level, the higher the requirements for the gloves used.

The role of cleanroom gloves

Test methods for dust-free performance of dust-free gloves

I. Dust-free performance test – LPC1. LPC: refers to the number of particles generated per unit area of the product, unt: pcs/cm2 Generally tested using the liquid particle stirring method.

2. Test principle: the glove or finger cover sample is placed in the liquid of the beaker, the water flows through the action of stirring force, thus the particles on the surface of the sample are released into the solution, these particles are calculated by the automatic liquid particle sub-counter or optical microscope, and then divided by the area of the sample to arrive at the number of particles per unit area.
Note:
①. Particles from severe abrasion are not taken into account in the test.
②. Small differences between one laboratory and another during the test can result in large differences in the test fluid. It is therefore recommended to test several sets of comparative experiments in the same laboratory and with the same testing technique.
3. Test equipment and materials: shaker, beaker, tweezers, glassware, purified water >18MΩ, liquid particle counter, glass stirring bar, several samples.
4. Test environment: Clean room or clean bench with air up to ISO class 5.
5. Experimental steps.
a) Clean the beaker, glassware and tweezers.
b) Clean the outer bag of the gloves with deionised water, dry the surface of the bag in a clean environment and open the bag with clean stainless steel scissors.
c) Use clean tweezers to remove one glove at a time.
Note: If the product is to be used for several days after unpacking, seal it in a clean bag.
d) Place the removed glove in a beaker. Pour 750 ml of deionised water into the glove and allow the overflow to flow
in the beaker so that the glove is completely submerged. The finger gloves are tested in the same way as the gloves, by immersing them in 750 DI water and recording the volume of water added, Vs.
e) Place the beaker with the glove or finger glove on a horizontal rotator and rotate at 150 r/min for 10 minutes.
f) Switch off the apparatus and remove the beaker.
g) Remove the glove or finger cover from the beaker using clean tweezers and drip the water from the glove or finger cover into the beaker.
h) Count (test) the number of particles in the beaker for a given size range.
i) Accurately record the blank value before placing the sample.
j) Determine the area of the glove or finger glove using the method described in Appendix A.
k) Subtract the average blank value and record the number of particles per unit volume of glove or finger glove surface.
6. Determination of the number of particles in liquid form.

a) Liquid particle counter settings should follow the following.

  • Sampling rate – using a calibrated flow sensor for sampling.
  • Volume – 25ml (the exact sample volume should also be selected according to the different instruments).
  • Count particles ≥ 0.5um, 1um, 2um, 5um, 10um respectively (some counters can also count particles smaller than 0.5um; so all tests should record ≥ 0.5um particle count.)
b) The operation of the particle counter and the calculation of contamination levels should fulfil the following points.
  • Dilute the sample with water to the detection limit of the device and transfer to the beaker of the counter. Volume of sample transferred/total volume after dilution = dilution rate (DF).
  • Stir the sample with a glass rod for 20 minutes to ensure that large particles can be separated before detection. Stirring should not create a centre; a centre can become entrapped in air and cause bias in the test.
  • At the end of stirring 5 sets of data are measured, the first two sets are removed and the remaining 3 sets are averaged.
  • Result = (average number of particles – average blank value) x volume x (DF) ÷ area.
  • In the above equation: LPC’s are expressed in units of pcs/cm², sample’s and blank count results are expressed in units of pcs/mL. DF: Dilution factor. Area: the inner and outer area of the glove or the sum of the inner and outer areas of the ten finger gloves (cm²).
II. Dust free performance test – ion1. Ion test principle: ions are extracted from the glove surface using a suitable extractant and the content of ions on the glove surface is analysed by an IC tester.

2. Test equipment and materials: pure water (conductivity > 18 MΩ and containing particles < 0.2 μm), measuring cylinder, beaker, labware, extraction solution 750 ml (solution A: 100% deionised water solution B: 100% analytical isopropanol solution C: analytical reagent or mixed solution), stainless steel scissors, stainless steel tweezers, ion tester
Note:
①. Solvent purity: To ensure the accuracy of the test, the reagents selected should be of a certain purity.
②. Samples need to be packaged.
③. The unit of weight must be accurate to 0.01mg.
3. Test environment: Clean room or clean bench with ISO 5 air.
4. Test procedure.
a) Prepare one 1L beaker and one wide mouth beaker for each sample and blank experiment respectively. Run a minimum blank for each group of 10 extracts.
b) Fill 500 ml of extraction solution into a measuring cylinder (glove extraction solution is solution A)
c) Unwrap a bag of product with clean scissors and use forceps to clip a sample to the beaker.
Note: If the product is to be used for several days after unpacking, reseal or pack in a clean bag.
d) Using clean stainless steel tweezers, take a glove or 10 finger covers and place in a wide mouth beaker, keeping the mouth of the glove or finger covers open, and add the extraction solution.
e) Pour 250ml of the extraction solution into the inside of the glove, making sure that the solution can be washed over the entire inner surface of the glove. Place the glove in the beaker and pour the remaining 500ml of solution into the beaker (in the event of leakage, a new sample should be taken for testing). The finger gloves should be unfolded and tested and each finger glove must contain the extraction solution.
f) Place a suitable lid on both the beaker containing the sample and the empty beaker.
g) Gently rotate the beaker with the sample for 10 s to wet the surface of the glove or finger cover. Rotate the blank beaker in the same way.
h) Samples and blanks are allowed to stand at (22±5)°C for 10-20min.
l) It is usually necessary to gently swirl the sample container and the blank solution beaker once for 10s.
j)Remove the lid of the sample beaker and the blank beaker
k)Using clean forceps, clip out the finger cover or glove of the beaker and pour the water from the finger cover or glove into the beaker.
l) Re-cover the beaker from which the sample was taken and the blank beaker and set aside.
m) Store the sample beaker and blank beaker until the test begins. Before testing, gently swirl the beaker and shake the liquid for 10s to mix the liquid.
n) Perform the test using liquid phase ion chromatography. Results are given in units of ug/g or ug/cm². Report the weight of the sample by recording the surface area. The area of the glove or finger cover needs to be recorded inside and outside, expressed in cm².
III. Dust-free performance test – non-volatile residues
1. Principle of testing for non-volatile residues: Extraction of residual material from the glove surface using IPA solution, evaporation of volatile residues and analysis of the weight of non-volatile permanent residues.
2. Test equipment and materials: analytical balance, evaporation dish, beaker
3. Test environment: Clean room or clean bench with air up to ISO Class 5.
4. Test procedure.
a) Wash the dish used for evaporating the sample and for the blank test and dry it at 110 (±10) °C (230 [±18] °F) for 1 hour.
b) Place the evaporated dish in a desiccator and dry to room temperature.
c) Weigh the evaporated dish on an analytical balance to an accuracy of 0.01 mg.
d) Weigh the gloves or 10 finger gloves on an analytical balance to 0.01mg.
e)Evaporate the sample solution and the blank solution until the remaining amount of solvent is suitable for the evaporation dish.
f) Transfer the evaporated sample solution quantitatively to the evaporation dish. Wash the beaker with the extraction solvent, transfer the cleaned solvent to the evaporation dish and do so 3 times.
g) Evaporate at a temperature 10°C (18°F) below the boiling point of the extraction solvent. evaporate the remaining residue at 110°C (±10)°C (230[±18]°F) for at least 1 hour.
h) After the evaporated dish has cooled to room temperature in a desiccator, weigh it to the nearest 0.01.
i) Calculate the amount of residue using the initial weight and the final weight
j) The results are expressed in ug/g or ug/cm2. Data to be recorded include the weight of the sample, the surface area of the sample.
TNVRm = (Wf – Wi) x 106 ÷ Wg
Where: TNVRm = unit weight of permanent non-volatile residual material (ug/g)
Wf = weight of evaporation dish and sample after the experiment (g)
Wi = weight of the initial evaporation dish (g)
Wg = weight of gloves or 10 finger covers (i.e. weight of sample g) and
TNVRa = (Wf – Wi) × 106 ÷ A
TNVRa = permanent non-volatile residue per unit area (ug/cm²)
A = area of the glove or 10 finger covers (i.e. total internal and external area of the sample cm²)
IV. Dust-free performance test – Determination of glove finger cover area
1. Purpose:
To accurately calculate the amount of particulate matter per unit area, or the amount of non-volatile residue per unit area, it is necessary to know the exact area of the glove or finger cover.
2. Equipment required.
Scissors or sharp knife, analytical balance (accuracy not less than 0.01g), ruler
3. Number of samples required.
At least 3 test samples of the same size and from the same batch.
4. Average weight.
Cut off the rolled edge of the glove or finger cover, weigh the glove or finger cover to an accuracy of 0.01g and calculate the average weight.
5. To obtain a sample of standard area.
Cut a piece of material not less than 25 cm² from the palm of the glove next to the fingers (or the back of the hand if there is a pattern on the palm). Accurately measure the area of the cut material. For finger covers, unroll as much as possible, cut off the rolled edge and cut along the length, taking 25cm² of material.
6. Weighing of cut block samples.
Weigh the cut pieces to the nearest 0.01g
7. Calculation of the area of the cut block sample.
The area of the inner and outer surface of the sample is calculated as follows.
A = 2 x (Wg ÷ Wc) x Ac
A = area of the inner and outer surface of the sample, in cm²
Wg = weight of the glove, in g
Ac=area of the cut off sample in cm²
Wc = weight of the cut off section, in g
8. Reported results.
The area accuracy is 10cm², if the area is calculated to be 1234.56cm2, then the report is 1230cm²

Dust-free performance test - Determination of glove finger cover area

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The Must Have Antistatic Shoes Resource List

Anti-static shoes are working shoes worn by workshop and advanced laboratory in microelectronics industry, such as electronic semiconductor devices, computers, electronic communication equipment and integrated circuits, in order to reduce or eliminate static hazards. Anti-static shoes can guide static electricity from the human body to the earth, thereby eliminating static electricity in the human body, while effectively suppressing the dust generated by the movement of people in the dust-free room. It is suitable for pharmaceutical factories, food factories, electronic factories, clean workshops, laboratories, etc. Anti-static shoes are made of dispersive PU or PVC materials. Anti-static and anti-skid materials are used for soles, which can not only absorb sweat and deodorize, but also achieve anti-skid and anti-static functions. They are integrated with the upper and then reinforced on-line. It can effectively release static electricity, form a complete anti-static system with anti-static clothing.
  •  Antistatic Shoes
  • Dual Hole Slippers
  •  Instructions
  • Detailed Introduction
  • Testing Methods
  • Differences
  •  National Standards
  •  Applied Range
  •  Technical Requirements
  •  Worth-noting

Antistatic Shoes

Antistatic shoes are also known as electrostatic shoes and antistatic working shoes.
It can be categorized as: antistatic shoes and antistatic slippers.
The styles of antistatic shoes can be basically divided into:
1, Low-cut shoes: medium shoe (full vamp shoes), hole (eyelet) shoes, mesh (surface) shoes, steel toe boots.
2, Sleeve boots: soft sole boots, hard sole boots.
3, Anti smashed shoes: ladle head shoes.

Dual Hole Slippers

Product Name: Anti static dual hole slippers (separable cut / no cut) /PU flip flops
Material: High quality PU leather (ISO9001 certified) environmental protection PU material.
Surface resistance:106Ω-109Ω
Specifications: 22cm to 28cm (Size 34 to 46).
Features: Durable, decent, soft upper, easy to clean and wear.
Wearing antistatic cleaning shoes is the most effective and reliable way to release the electrostatic charge of the operator.
PU antistatic slippers are made of static dissipative material PU (polyurethane).
Introducing HAD system based on kinematics and physiology, the shoe body is light, soft, comfortable and permeable, and it is not easy to feel fatigue for a long time.
High quality and low price is a relatively economic choice. It is suitable for use in electrostatic sensitive area.
Dual Hole Slippers

Instructions

1. Anti-static shoes are protective shoes that can eliminate static electricity and prevent electric shock below 250V. This product is manufactured according to GB4385-1995 standard.
2. It is mainly applicable to all places where electrostatic hazards may occur such as combustion and explosion due to static electricity in human body (such as petroleum, chemical industry, mining, printing, rubber, medical treatment, purification, electronics, etc.)
3. Anti-static shoes and conductive shoes should not wear with insulated wool stockings and insulated insoles. Anti-static shoes should not be used as insulating shoes.
4. The place where antistatic shoes are used should be antistatic ground, and the place where conductive shoes are used should be conductive ground to achieve a good antistatic or conductive effect.
5, Anti-static shoes should be used in conjunction with antistatic clothing. Pay attention to the cleanliness, waterproof and moisture proof of the products.
6. In general, resistance test should be carried out within 200 hours during wearing. If resistance is not within the prescribed range, it can not be used as anti-static shoes. Antistatic shoes require resistance between 100K ohms and 1000M ohms.

Detailed introduction

Electrostatic shoes are made of dispersive PVC or PU foaming materials. They are integrated with the upper cut and then reinforced. It can effectively release static electricity, and at the same time with anti-static clothing to form a complete anti-static system. Electrostatic shoes are flexible and light, with anti-static EVA in the middle sole, which can relieve foot pressure and make them more soft and comfortable. The fabrics are: PVC leather/leather/genuine leather/canvas/conductive silk/T/C fabrics. The completed shoes are beautiful and elegant, strong and anti-skid, with excellent wear resistance (5 times higher than ordinary soles), and more environmentally friendly. It is the best selling high quality electrostatic shoe in the world.
Characteristics: it can induce static electricity, shoes do not precipitate dust, and can be more effective against dust and antistatic.
Applications: Electronic appliances, LCD/LCM/LED, semiconductor production, instrumentation, microelectronics, pharmaceuticals, food etc.
Sole resistance: 10^6-10^9 Ω.
Size available: Size 34- Size 50 (220mm-300mm).
Material: PVC, PU, canvas, antistatic cloth, customizable upon requests.

Testing Methods

1. Instruments
A. Test instruments can output DC voltage 100V±2V. The measurement accuracy can be within 5%, and it can ensure that the energy consumed on the test sample is not more than 3W. The precision of the voltmeter and ammeter is 2.5 grade, and the measuring range can meet the requirement of measurement.
B. Inner electrodes are made up of steel balls with a total weight of 4KG and a diameter of 5MM. Anti oxidation treatment is necessary before use.
C. Outer electrode are copper plates. It must be treated with oxidation and cleaned with alcohol before use.
2. Preparation of test samples
A. Sample preparation
Clean the sole surface of the shoe with ethanol. Wash the sole with distilled water and dry it according to the prescribed circumstances. To prohibit the use of organic matter will cause corrosion of the soles, swelling and deformation of organic substances. The sole surface should not be worn out. The conductive layer of 180*40MM should be laid on the clean sole and dried under the prescribed environmental conditions.
B.Measurement of resistance value of conductive coating.
The device for measuring the resistance of conductive coatings consists of three conductive metal poles with a top radius of 3MM±2MM. There are two poles with a distance of 35MM±0.2MM. And connected by metal wires. The third pole is 160MM±5MM from the other two pillars, and are insulated from the other two pillars.
Put the shoes coated with conductive layer on the specified metal posts. The forefoot part of the shoes should be placed on two pillars 35MM apart, and the heel part on the third pillar. All three pillars must be in contact with the conductive coating. Then, the resistance between the front two columns and the third column is measured with the prescribed test instrument. The resistance value must be less than 1KΩ by measuring the circuit principle.

3. Test conditions for antistatic shoes.
Environmental requirements: temperature 20℃±2℃; relative humidity: 30%±3%.
A. Test samples shall be placed for more than 24 hours under environmental conditions.
B. If the test cannot be carried out in the prescribed environment, the test must be completed within 5 minutes after the test sample is removed from the environment.
4. Test process for antistatic shoes
Fill the sample shoes with steel balls according to the regulations (if the upper height is not enough, all conductive steel balls can not be filled, insulating materials can be used to increase the upper height). The test sample of the steel ball is placed on the prescribed external electrode, and the prescribed DC power supply is connected between the internal and external electrodes for 1 minute. Measuring circuit principle.
Record or calculate the voltage and current value after the specified time.

Differences

1. Conductive shoes and antistatic shoes have a same function, which is, both can eliminate static electricity.
2. Conductive shoes and anti-static shoes should be maintained after use, and a test of resistance value of shoes should be carried out after a period of time. If the test does not meet its standard, it can not continue to be used and needs to be updated in time.
Antistatic shoes and conductive shoes belong to two different safety shoes with following different functions:
1. Anti-static shoes should be used with anti static clothing, so that it can effectively prevent static electricity.
2. Conductive shoes and anti-static shoes can not be used with insulating insoles. These two kinds of safety shoes do not match their functions.
3. Antistatic shoes can prevent electric shocks below 250V, while conductive shoes must never be used in electric shock places.
4. Anti-static shoes must not be used as insulating shoes.
5. Conductive shoes and anti-static shoes are used in different ground environments. Anti-static shoes are used in anti-static ground, and conductive shoes are used in conductive ground.

National Standards

PRC National Standard for Electrostatic Shoes
Technical requirements for.GB4385 – 1995 antistatic shoes and conductive shoes
1. Test instrument can output DC voltage 100V±2V.
The precision of the voltmeter and ammeter is 2.5 grade, and the measuring range can meet the requirement of measurements.
A1.2 The inner electrode consists of steel balls with a total weight of 4kg and a diameter of 5mm each. Anti oxidation treatment is necessary before use.
A1.3 The outer electrode is copper. It must be treated before oxidation and cleaned with ethanol.
A2 Preparation of test samples
A2.1 Sample preparation
The sole surface of the shoes is cleaned with ethanol. Wash the sole with distilled water and dry it according to the conditions prescribed in A3.1. It is strictly prohibited to use organic substances that will cause corrosion, bloat or deformation of the soles. The sole surface should not be worn out. The cleaned sole should be coated with a conductive layer of 180 mm×40 mm as shown in Fig. A1 and dried under the environmental conditions specified in A3.1.
A 2.2.1 Device for measuring the resistance of conductive coatings consists of three conductive metal pillars with a top radius of 3 mm±0.2 mm. The two poles are 35mm±0.2mm, and are connected by metal wires. The third post is 160mm± 5mm from the middle of the other two columns, and is insulated from the other two pillars.
A2.2.2 Put the shoes coated with conductive layer on the metal column specified by A2.2.1. The forefoot part of the shoe is placed on two pillars 35 mm apart, and the heel part is placed on the third pillar. All three pillars must be in contact with the conductive coating. Then the resistance between the first two columns and the third column is measured with the test instrument specified in A1.1. The measuring circuit principle is shown in Fig. A2. The measured value must be less than 1kΩ.
2. Introduce the relevant standards of antistatic safety shoes.
European Standard EN 344:1997 “Safety, protective and occupational footwear for professional use”. The European Standard was formulated by the Technical Committee of CEN/TC61 “Foot and Leg Protection Products”, with BSI as its secretariat. This standard stipulates the structure and performance indices of safety protective shoes, such as style design, whole shoes, upper, lining, tongue, inner sole and outer sole. The test methods specified in the standard are similar to other similar standards. The principle of the method is generally applicable to most safety and anti-static protective shoes. The main indicators are as follows:
Impact resistance of Toe-cap
In the impact test with steel impact hammer of specified weight, the clearance height under the cap should be less than the specified value when the cap is impacted, and there should be no penetrating cracks in the direction of the test axis. It is noteworthy that the weight, specifications, impact height and the structure of the test machine are different in various national standards, and should be distinguished in actual testing.
Anti piercing performance
The test machine is equipped with a pressure plate, and the pressure plate is equipped with test nails. The test nail is a cutting-off tip. The hardness of the nail head should be greater than 60HRC. The sole sample is placed on the chassis of the testing machine, where the test nail can be pierced through the outer sole. The test nail pierces the sole at a speed of 10 mm/min±3 mm/min until it is pierced.
Record the maximum force required. Four points on each sole were selected for the test (at least one point on the heel). Each point was not less than 30 mm apart, and the distance from the edge of the inner sole was more than 10 mm. The bottom of the anti-skid block should be punctured between blocks. The 2 points in the 4 points should be tested at a distance of 10-15 mm from the edge line of the planting floor. If humidity has an effect on the results, the sole should be immersed in deionized water at 20℃±2℃ for16±1 hours before testing.
Electrical properties
After the shoe sample is adjusted in dry and wet atmosphere, the clean steel ball is filled into the shoe and placed on the metal probe device. The resistance between the first two probes and the third probe is measured by the specified resistance measuring instrument. In general, the resistance of conductive shoes should not be greater than 100K ohm; the resistance of antistatic shoes should be between 100K ohm and 100M ohm.
4. Requirements for anti-skid outsole
The standard provides for testing the anti-skid coefficient of anti-static working soles, but stipulates the design and specifications of anti-slip blocks, such as the thickness of soles, the height of anti-slip blocks and the distance from the edge of soles.
5. Anti static shoes storage
5.1 Places
It should be stored in a dry and ventilated warehouse to prevent mildew. It should be stacked above 0.2M from the ground and wall, and 1M away from all heaters. Avoid contacting with oils, acids, alkaloids or other corrosive substances.
5.2 Valid period
From the date of production, products over 18 months should be inspected in accordance with the provisions of 5.2 of this standard, and can only be sold and used if they meet the requirements.
6. Use of antistatic shoes
A. Wearing antistatic shoes and conductive shoes without thick wool socks and insulated insoles. The place for using antistatic shoes should be anti-static floor. The place where conductive shoes should be used should be conductive ground.
B. In the process of wearing, the resistance test should not be more than 200H.

Applied Range

It is suitable for pharmaceutical factories, food factories, electronic factories, clean workshops, laboratories, etc.

Instructions

1. Anti-static shoes and conductive shoes should not be worn with insulated wool stockings and insulated insoles at the same time. Anti-static shoes should not be used as insulating shoes.
2. The place where antistatic shoes are used should be antistatic ground, and the place where conductive shoes are used should be conductive ground to achieve a good result.
3. Antistatic shoes should be used in conjunction with antistatic clothing. Pay attention to the cleanliness, waterproof and moisture proof of the products.
4. Wear resistance test should not be more than 200 hours in the wearing process.

Technical Requirements

1. Wearing places
1.1 Antistatic rubber soles
Anti-static rubber soles are mainly used to prevent burning and explosion caused by static electricity in human body (for example, some places in rubber, chemical, printing, medical, electronic and other industries). At the same time, it can also avoid the electrical shock and fire caused by electrical equipment below 250V.
1.2 It is forbidden to wear anti-static rubber sole shoes for staff who’s in danger of electric shock in maintaining power equipment or handling high-voltage electrical equipment.
2. Performance indicators
2.1 Electrical performance indicators
During the wearing period of shoes, the resistance values of anti-static and conductive rubber soles were measured according to GB4386-84 “Method of testing resistance for anti-static shoes”. The resistance of the antistatic rubber soles sole must be in the range of 0.5× 10^5 Ω to 1× 10^8Ω.
2.2 Other performance indicators
2.2.1 Other performance requirements of antistatic and conductive rubber sole shoes must meet the relevant national standards and technical requirements of footwear.
2.2.2 In the structural design and material selection of anti-static and conductive rubber soles, it is necessary to take into account that the resistance of the sole changes minimally under the influence of wear and pollution.
2.2.3 Antistatic and conductive rubber soles with special requirements (e.g. acid, alkali and oil resistance) should also meet the corresponding technical standards.
3. Wear requirements
3.1 In order to ensure the effect of eliminating static electricity, when wearing anti-static rubber soles, the resistance of the ground should not be less than 1.0×10 ^ 8Ω; and when wearing conductive rubber soles, the resistance of the ground should not be less than 1.5×10^5Ω.
3.2 During the wearing process of shoes, the soles of anti-static rubber soles and conductive rubber soles shall not be contaminated with insulating impurities.
3.3 In the process of wearing shoes, attention should be paid to avoid wearing thick socks with strong insulation or wool, as well as insulating insoles.

Worthnoting


Anti-static shoes should not be worn with insulated wool socks and insulated insoles. Anti-static shoes should not be used as insulated shoes.
The place where antistatic shoes are used should be antistatic ground, and the place where conductive shoes are used should be conductive ground.
Antistatic shoes should be used in conjunction with antistatic clothing. Pay attention to the cleanliness, waterproof and moisture proof of the products.
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Everything You Need to Know About Antistatic & ESD

Static electricity is a natural phenomenon, which can be generated from different ways, such as contact, friction, stripping and so on. Electrostatic protection technologies, adopted by electronics, semiconductors, petroleum, ordnance, textile, rubber, aviation and military fields, resort to reduce the loss caused by static electricity.
  • Precautionary Measures
  • Grounding
  • Shield
  • Neutralization
  • Protective Equipment
  • Daily Life Common Sense
  • Explanation on Electrostatic
  • Main ESD Prevention Products
  • Electrostatic system

Precautionary Measures

There are three main anti-static measures: antistatic clothing, antistatic shoes and anti-static wrist bands.

Anti static shoes and anti-static wrist bands are used to conduct static electricity so as to avoid accumulation on the human body.

Antistatic garments & shoes

Common clothes produce a large static voltage (> 1000V) while the wearer moving around. This wouldn’t occur to antistatic clothes, and that’s the main reason for wearing antistatic clothes.

Long strip material anti-static clothing can not shield the static electricity generated by clothing (still >1000V after wearing). While he grid material antistatic clothing can do its job (<200V).

The static electricity is introduced into the outer ground line of the factory through conductive floor boards and the ground wires .

The prevention includes preventing static electricity generation and preventing its damage.

Electrostatic protection is a long-term system engineering, any fault or carelessness will lead to the failure of electrostatic protection.

Mainly the measures for electrostatic protection in the production process are electrostatic leakage, dissipation, neutralization, humidification, shielding and grounding.

Human body electrostatic protection system usually consists of anti-static wristband, anklet, work clothes, shoes & socks, caps, gloves or fingerstalls etc., with electrostatic leakage, neutralization and shielding functions.

The ground anti-static treatments are anti-static ceramic steel-based composite movable floor, anti-static steel movable floor, anti-static ceramic floor tiles and so on.
Grounding
Grounding is very important to reduce the electrostatic charge on the conductor, the human body is a conductor, also a main source of electrostatic generation. Therefore, we must reduce the static charge generated by contact with the sensitive electrostatic components. Prevention of static electricity on the human body is best through grounding.

Some grounding devices:

In industry, wristband is the most commonly used grounding device. The wristband will safely and effectively drain the static charge from your body. Reasonable use of a wristband requires reasonable contact with the skin. A dirty or loose wrist strap may retain the static charge, which makes the antistatic control will fail. Conductive footwear or foot grounding can be used to overcome shortcomings of wrist bands.

Work Station Grounding Device

Conductive or electrostatic dissipative working surfaces are an indispensable part of an electrostatic safety workstation, especially where manual assembly occurs. While using wristbands, it is necessary for a clean working surface to be grounded properly at a joint. Conductive or electrostatic dissipative materials can produce electrostatic charges, however., when they are properly grounded, they can effectively drain static charges.

Shield

The next concept is to isolate parts and components during storage or transportation. It is isolated from a charged object or a charged electrostatic field. Insulator is the best way to prevent electrostatic discharge during storage or transportation. Since grounding cannot remove static charges or insulators, it is necessary to isolate sensitive parts and components from them. Reducing conventional plastics and other types of insulators in stationary working, shipping and handling areas is the best way to isolate products from insulators. Isolation can also be done by limiting access to the entire work area or workstation. Finally, we take advantage of the fact that electrostatic charges cannot enter containers made of conductive materials or layers. This effect is called the Faraday cup effect. When storing and transporting electronic components or loading circuit boards, ensure that containers with similar Faraday cup characteristics are used, and these containers will be isolated from electrostatic injuries.

Neutralization

Utilizing electrostatic elimination equipment, its main component is ion generator.

Neutralization is important because earthing and isolation will not release charge from insulators such as synthetic fabrics or conventional plastics. Neutralizing or removing the charge generated in insulator is called ionization. Ions are simply charged substances existing in the air. Ions are produced by natural energy materials. Including sunlight, lighting, open-air flame and radiation. We can get trillions of ions through ion generators, which use high voltages to produce a balanced mixture of charged ions, and fans to help ions drift to objects or regions to neutralize. Ionization can neutralize static charges on insulators in eight seconds, thus reducing their potential damage. Ionization is not a substitute for grounding or isolation. It only reduces the possibility or risk of electrostatic discharge accidents.

Protective Equipment

Personal static eliminator mainly refers to contact static eliminator and auto-sensor static eliminator.

Contact static eliminator

Contact hand-held personal electrostatic eliminator is a device that eliminates static electricity on human body or metal objects by touching metal objects with hand-held devices. But this is only temporary. In daily life, static electricity is produced all the time. After using contact static eliminator for a period of time, our body will feel electric shock when it contacts the electrostatic object/metal conductor again. So when we use the product, we need finish to the work as soon as possible.

Auto-sensor static eliminator

Automatic personal static eliminator is a device that automatically detects the static electricity in the surroundings and then automatically eliminates the static electricity. We don’t need any operation. The most outstanding feature of this automatic key chain is its exquisite workmanship, anti-static load up to 40,000 volts, and the ability to eliminate static electricity continuously.

Daily Life Common Sense

In daily life, people often accumulate static electricity due to clothing, climate, friction and other reasons. When they bump into metal, people will suffer from electric shock pain. Psychological pressure may be caused in some cases. If you avoid touching iron for a while, you may accumulate more electric charges on your body, sooner or later you will suffer from stronger electric shocks.

1. In the house, the rubbing of carpet and sole may produce static electricity, and outside, you may also be electrified by wind. Be careful when you enter or exit metal gate, your hands may experience shock. If this happens repeatedly, the following measures can be taken to avoid electric shock:

1.Don’t touch an iron door directly with your hands. Instead, hold the keys before that(usually you can avoid electric shock), touch the metal with the tip of a key, the electricity on your body will be released and you won’t get shocked.

Principle: Pain caused by hand discharge is due to high voltage discharge, because a sudden contact of your hand and metal door leaves a small area for discharging, resulting in instantaneous high voltage. If you take out the key in your pocket and hold it in a large area (a bunch of keys can’t transfer much electric charge by themselves, so there won’t be an electric shock at this time), then use the tip of a key to contact the large conductor. At this time, the contact point of discharge is not a point on the skin of the hand, but the tip of the key, so the hand will not feel it. (Maybe the key! If it feels pain.)

2. Frequent electric shocks occur when getting off the taxi. The main reason is that static electricity accumulates when the body rubs against the seat when getting off, and when the door closes, the hand will be shocked when it suddenly touches the iron door.

If this often happens, it’s better to take notice when you get off the car, that is, when your body rubs against your seat, you can hold the metal door frame in advance. When static electricity is generated by friction, you can remove static electricity from your body at any time, instead of discharging when you suddenly touch the iron door while getting off.

Explanation on Electrostatic

In order to effectively combat and prevent ESD (electrostatic discharge), the right equipment must be used in the correct way. Because of a series of powerful closed-loop ESD prevention, monitoring and ionizers, ESD can be regarded as a process control problem.

Electrostatic discharge (ESD) is a familiar and underestimated source of circuit board and component damage in electronic assembly. It affects every manufacturer, regardless of its size. Although many people believe they produce products in an ESD-safe environment, in fact, ESD-related damage continues to cost the world’s electronics manufacturing industry billions of dollars a year.

What is ESD?

Electrostatic discharge (ESD) is the sudden flow of electricity between two electrically charged objects caused by contact, an electrical short, or dielectric breakdown. A buildup of static electricity can be caused by tribocharging or by electrostatic induction. The ESD occurs when differently-charged objects are brought close together or when the dielectric between them breaks down, often creating a visible spark. The charge is stable under two conditions.

1. When it “falls” into a conductive but electrically insulated object, such as a metal screwdriver with a plastic handle.

2. When it resides on an insulating surface (e.g. plastic), it can not conduct on it.

However, if an electrically insulated conductor (screwdriver) with sufficient high charge is close to an integrated circuit (IC) with opposite potential, the charge “crossover” causes electrostatic discharge (ESD).

ESD occurs very quickly at very high intensity, usually producing enough heat to melt the internal circuit of semiconductor chips, which seemingly blows out small bullet holes under an electron microscope, causing immediate and irreversible damage. What’s more, a tenth of the cases are so bad that the whole component fails in the final test. In the other 90% cases , ESD damage only causes partial degradation – meaning that the damaged components can pass the final test without detection, and premature on-site failure occurs only after shipment to the customer. It will dishonor a manufacturer to have to correct any manufacturing defects.

However, the main difficulty in controlling ESD is that it is invisible but can damage electronic components. To produce a discharging that can hear a beep, a considerable charge of about 2,000 volts needs to be accumulated, while with 3,000 volts you can sense slight shock and with 5,000 volts you may see sparks.

For example, common components such as complementary metal oxide semiconductor (CMOS) or electrically programmable read-only memory (EPROM) can be destroyed by ESD potential differences of only 250 volts and 100 volts, while more and more sensitive modern components are out there. Including the Pentium processor, it can be destroyed by only 5 volts.

The problem is compounded by activities that cause damage every day. For example, in the vinyl factory floor, there is friction between the floor surface and the shoes. As a result, pure charges accumulate between 3 and 2,000 volts, depending on the relative humidity of the local air.

Even the friction generated by the natural movement of workers on the platform can produce 400~6000 volts. If the worker has treated the insulator during the PCB dismantled or packed in foam box or bubble bag, the net charge accumulated on the workers can reach about 26000 volts.

Therefore, as the main source of ESD hazards, all staff entering the electrostatic protected area (EPA) must be grounded to prevent any charge accumulation, and all surfaces should touch ground to maintain the same potential of everything and prevent ESD from occurring.

Main ESD Prevention Products

The main products used to prevent ESD are wristbands, with curly corduroy and dissipative surfaces or pads – both must be properly grounded. Supplements, such as dissipative footwear or heel straps and suitable clothing, are designed to prevent people from accumulating and maintaining net charges while moving in an electrostatic protection area (EPA).

PCB should also prevent ESD from internal and external transportation during and after assembly. There are many PCB packaging products that can be used in this area, including shielding bags, shipping boxes and mobile trolleys. Although the correct use of these devices will prevent 90% of ESD-related problems, in order to reach the final 10%, another protection is needed: ionization.

The most effective way to neutralize assembly equipment and surfaces that generate electrostatic charges is to use an ionizer, a device that blows ionized air out of the working area to neutralize any charges accumulated on insulating materials.

Antistatic Gloves

Antistatic Gloves

A common fallacy is that because a bowl belt is attached to the workstation, the charges of insulators in the area, such as polystyrene cups or cardboard boxes, will dissipate safely. By definition, insulators do not conduct electricity, and it is impossible to discharge them in addition to ionization.

If a charged insulator is retained in EPA, it will radiate an electrostatic field, causing a net charge to any nearby object, thus increasing the risk of ESD damage to the product. Although many manufacturers try to prevent insulation materials from their EPA, this method is difficult to implement. Insulating materials are too much part of everyday life – from operators’ comfortable foam mats to plastic covers.

Because of the use of ion generators, manufacturers can accept the fact that some insulating materials appear in their EPA. Since ion generation systems continuously neutralize any charge accumulation that may occur on insulators, they are a reasonable investment for any ESD program.

There are two forms of ion generating equipment in standard electronic assembly:

* Desktop type (single fan)

* Overhead equipment (with a series of fans in a single over top unit).

There are also indoor ion generators, but they are mainly used for cleaning rooms.

To use which one depends on the size of the protected area. Desktop ion generators will cover a single working surface, while overhead ion generators will cover two or three. Another advantage is that the ion generator can also prevent dust from sticking to the product and may degrade the appearance.

However, without proper testing and monitoring of the effectiveness of ESD devices, no protection plan is perfect. First-class ESD control and ionization experts report examples of manufacturers using failed (and therefore useless) ESD devices without knowing their failure.

To prevent this, in addition to standard ESD equipment, ESD vendors also provide a variety of constant monitors, which automatically alarm if a performance exceeds the requirements. The monitor can be used as an independent unit or linked together in the network. It also has an automatic data acquisition network software that displays the performance of operators and workstations in real time.

The monitor can simplify ESD plans by eliminating many routine tasks, such as ensuring proper measurements of bowl belts every day, balancing and correct maintenance of ion generators, and no damage to the worktable grounding points.

Conclusion

The first step in preventing ESD is to correctly evaluate how small details can cause irreparable damage if ignored. An effective plan requires not only the use of effective ESD protection equipment, but also rigorous operating procedures to ensure that all plant personnel are ESD safe.

Although many manufacturers use automatic bowl belt testers, it is common to see operators passing tests or failing because the bowl belt is too loose. Many operators attempt to pass the test by holding the tester close to the wrist with the other hand.

Nonetheless, the good news is that ESD is avoidable. The time and money invested in proper equipment and improved safety procedures will be rewarded by increasing the corresponding eligibility rate.

Electrostatic system

As an effective system for electrostatic protection, it is mainly composed of two parts: hardware and software.

The hardware part includes:

* Body electrostatic protection products

* Anti-static logistics transfer products

* Anti-static floor

* Anti-static operation system

* Anti-static earthing

Anti static grounding must be installed in the anti-static work area.

* Environmental control system

Temperature and humidity control equipment should be installed in the anti-static working area, and environmental cleanliness control system should be installed in the assembly of electrostatic sensitive devices with special requirements, so that the production environment can reach the corresponding cleanliness level.

* Special production assembly equipment

Production equipment such as mounter, Bonding, plug and pull, welding and so on should be adopted.

* Special antistatic products.

* Electrostatic measurement (monitoring) system

The software part includes:

* Training

* Antistatic technology and design documents.

* Professional standards for anti static electricity

* Operation procedures and rules and regulations

* Complete quality assurance system

* Anti-static signs

* Storage and transportation requirements

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Classification on Electrostatic Garments

How to classify electrostatic garments to different dust free clothing grades?

Dust-free clothes are not unfamiliar to everyone. They are suitable for dust-free workshops of electronic semiconductors, pharmaceuticals and precision instruments. Dust-free workshops are divided into different grades. So cleanroom clothes have different grades. What are they? Let’s take a look.

Classification on Electrostatic Garments

First of all, it is divided into 100, 1000 and 10000. The highest grade is 100. For example, electrostatic fabrics are divided into 0.25 grid, 0.5 grid and 0.5 stripes. Different fabrics correspond to different grades. The performance of antistatic clothing mainly depends on the conductive wires on clothing. The denser the conductive wires, the better the effect. It can also prevent dust and have good dust filtering function.

10,000-grade clothes, that is, stripes of 05, are worse than the mesh. They are generally used in coats, split suits, etc. They are suitable for electronic factories, food factories and so on. 1000-level 0.5 grid, the grid wire is more dense than the Striped electrostatic clothing, mostly used in electronic semiconductors, precision instruments, biopharmaceuticals and so on.

Class 100 is 0.25 grid, which is the cleaner clothes with higher grade on the market. It can be made into a single suit, which can better play a protective effect. It is suitable for aerospace, biopharmaceuticals, microelectronics and other industries with higher requirements.

All ESD clothes: AntiStatic ESD Jackets, ESD Lab Coats, AntiStatic ESD T-Shirts, ESD Polo shirts, AntiStatic ESD Woven Shirts, ESD Sweatshirts, AntiStatic ESD Trousers/Pants, ESD Dungarees, AntiStatic ESD Cleanroom Coveralls, ESD Cleanroom Lab Coats, AntiStatic ESD Gloves and finger cots, that you will find on our ESD shop guarantee minimum 50 industrial washes.

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Wash Before Wearing Antistatic Clearnroom Coveralls

Dust-free clothes, also known as anti-static clothes, are different from ordinary work clothes. They can not be used directly in production. Many people are not aware of this. Here’s a brief introduction

Wash Before Wearing Antistatic Clearnroom Coveralls

Cleanroom clothes themselves do not collect dust and stick dust, which has played a very good effect of dust and static electricity. However, when cutting, it will produce many small threads and exposed fibers. Some fibre dust may remain in newly produced clean clothes, which affect the performance of dust-free clothes. So before cleanroom clothes are used, they need to be cleaned. In order to have better effect, there are some sensitive people who need to wash and wear again to avoid physical allergies.

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What is PU Antistatic(ESD) Shoe？

Antistatic or ESD shoes are commonly seen in workshops of various industries, the main purpose is to transmit the electricity to the ground, thus eliminating the static electricity from the workers. However, there’re just endless styles and you may have heard a wide array of materials as well, such as PU, SPU, PVC, just to name a few.

Anti-static clean room shoes

Today we’re going to unveil the mysterious PU antistatic work shoes:

The shoe sole is made by the antistatic dissipative material PU(polyurethane), and the shoe cover & mesh are made of permeable and anti-static materials. The sole can reduce the electric resistance, and it is oil proof, alkali-resisting and acid-proof under harsh working environments. The shoes are usually not easily worn down.

Why choosing PU anti-static shoes?

  1. Soft, comfortable & permeable
  2. Light, endurable and feel like casual shoes
  3. Washable
  4. Anti-skidding, low-voltage friction,
  5. Suitable for pharmaceutical, cosmetics, labs, food factory and other industries which have strict requirements on electrostatic prevention
  6. Mitigating the tiring feeling you’d normally get for standing too long, especially for workers who need to stand all-day long, the shoes help to ease the pains with thick bottom and sole

Anti static ESD Cleanroom PVC Mesh Autoclavable Shoes

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Why Antistatic Shoes Don’t Prevent Electrostatic Discharge

Anti-static shoes are special protective shoes in special environment. They can prevent static electricity and dust. They are suitable for shoes worn in clean rooms such as biopharmaceuticals, electronics factories, aerospace, petrochemical and food factories. Sometimes they do not prevent static electricity long after they are worn. People may think they are broken. In fact,  the problem was that they don’t wear them in the right way. We need to pay attention when we use it.

Why Antistatic Shoes Don't Prevent Electrostatic Discharge

Some people like to wear socks when they wear work shoes, especially when it is cold in winter, cotton thick socks will lead to anti-static performance failure. Socks should wear thin nylon socks or conductive fiber socks, not wool or chemical fiber socks!

Cleaning is another important factor for ESD shoes. Employees need to clean and maintain after wearing them for a period of time. Cleaning is not just for employees to take home for cleaning, but for professional cleaning companies, so as to ensure its special function. Here we need to pay attention to check whether the anti-static effect is up to the standard before cleaning. If the anti-static effect is not up to the standard, it needs to be replaced immediately. Otherwise, it is a waste of money to wash out the non-wearable.

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Answered: Your Most Burning Questions About Antistatic Clothing

Antistatic clothing is made of special anti-static clean fabric. The fabric is made of special polyester filament and warp or zonal woven conductive fibers. It has the characteristics of high efficiency, permanent antistatic and dustproof, thin and smooth texture.

In the process of making garments, special sewing machine is used to reduce the production of particles effectively. The dust-free adhesive tape avoids the environmental pollution caused by lint come off. According to the level requirements, different styles are provided, and conductive fibers are sewn to keep the electrical continuity of each part of the garment; sleeves & trouser legs are special double-layer structure, and the inner layer uses conductive or anti-static ribs to meet the requirements of high-level dust-free environment.

Answered: Your Most Burning Questions About Antistatic Clothing

  • Description
  • Scope of use
  • Use of fabric
  • Environmental requirements
  • Do’s and don’ts
  • Maintenance
    • Packaging & storage
    • Preservation
  • Measurement references
  • Principle of ESD
  • Cleaning procedures
  • Antistatic standards in China

Antistatic Garment Description

Anti-static clothing is made of anti-static and dust-proof fabric (commonly known as conductive silk), which is made of special polyester filament and high-performance permanent conductive fiber by special technology. It has excellent and lasting anti-static and dust-proof function and can effectively release human static charge.

Scope of use

Suitable for microelectronics, photoelectricity, solar energy, medicine, bioengineering, food, cosmetics, petrochemical, military and other industries which are more sensitive to electrostatic micro-dust and require higher cleanliness.

Size Chart
Note: It may be customized with 5mm stripe, 5mm grid, 2.5mm grid material,  knitting techniques and other specifications are also customizable.
Color: White, blue, red, yellow, green, pink etc.

Use of fabric

The use of stainless steel fibers, sub-conductive fibers, anti-static synthetic fibers and polyester-cotton blended or blended fabrics, can
  • automatically corona discharge or leakage discharge
  • eliminate clothing and human static electricity,

in addition to clothing, they can also be used to make anti-static hats, socks, shoes and so on. In China, the performance index conforms to the GB12014-89 standard: the charge density of cloth is less than5μC

Environmental Requirements

Relative humidity less than 30%, the charge quantity of pure cotton clothing is relatively lower than that of chemical fiber clothing , anti-static clothing made of sub-conductor material should be worn in high-voltage work place; do not take off the clothes in flammable and explosive spaces; do not wear any accessories or metal items on anti-static clothing; when wearing anti-static clothes, you should also wear antistatic clothing stipulated in GB4385. Including but not limited to electrostatic shoes, ESD caps, anti-static gloves.

Do’s and Don’ts

  1. Anti-static clothing should be worn when the minimum ignition energy of combustibles is below 0.25 mJ under normal situation, where explosive gas mixtures continue to emerge or exist frequently in a short time or for a long time, and where explosive gas mixtures are likely to appear.
  2.  Do not put on or take off  in flammable and explosive spaces.
  3. Do not wear any accessories or metal objects with anti-static clothing.
  4. When wearing anti-static clothes, they should also be matched with anti-static shoes. At the same time, the ground should be anti-static floor and have a grounding system as well.
  5. Anti-static clothing should be neat and confirmed antistatic. After use, it should be washed with soft brush or wash with soft cloth dipped in neutral detergent, do not destroy the fabric.
  6. Anti-static work clothes should be cleaned with neutral detergent. When washing, do not mix with other clothes. Hand-washing or washing machine soft-washing procedures should be adopted to prevent the breakage of conductive fibers.
  7.  After wearing for a period of time, anti-static clothing should be tested. If the electrostatic performance does not meet the requirements, it can no longer be used as anti-static clothing.
  8. Do not put on or remove static clothing in places with danger of fire and explosion.
  9. Do not attach or wear metal objects with antistatic clothing in hazard places of fire and explosion.
  10. Outer clothing should completely cover the inner garments. The split jacket should cover the waist of the waistband.
  11.  When wearing anti-static clothing in fire and explosion hazardous locations, you should also wear anti-static shoes stipulated by relevant national standards.
  12.  Anti static clothing should be kept clean and antistatic. After use, brush with soft brush or soft cloth dipped in neutral detergent, ensuring not to damage the cloth fiber.

Maintenance

Packaging & Storage

In transportation, it should be noted that there must be a cover on the anti-static work clothes, and that the packaging should not be damaged so that it can prevent sun and high temperature contact. Dragging with hooks is strictly prohibited during handling.
Antistatic work clothes should be stored in dry and ventilated warehouses to prevent mildew and rot. During storage, keep a distance of 200mm from floor and walls and 1m away from all heating items . Direct sunlight should be avoided and outdoor placement prohibited.
Appropriate moth proofing measures should be taken when packaging and storing wool knitted antistatic clothing.

Preservation

Anti-static work clothes should be cleaned with neutral detergent. Do not mix with other clothes. Hand washing or washing machine soft washing procedures should be adopted to avoid the damage of conductive fibers. Washing water temperature should be below 40 degrees Celsius, rinse with normal temperature. The washing period is as short as possible, but must be rinsed sufficiently to remove residual detergent. Antistatic work clothes with flame retardant and oil proof properties shall not be used with bleach or organic solvents for decontamination.

Measurement References

GB 1335 Clothing size series
GB 2668 Men’s and women’s single coat specifications series
GB 2669 Men’s and women’s trousers specifications series
GB 2828 Batch by lot inspection sampling procedure and sampling table (for continuous batch inspection)
GB 3923 Determination of breaking strength and breaking elongation of woven fabric (strip method)
GB 4288 Household electric washing machine
GB 4385 Antistatic rubber soles and conductive rubber soles before safety technology

Principle of ESD

(1) First of all, anti-static clothing is a kind of clothing sewn with anti-static fabric to prevent the accumulation of static electricity on clothing. Antistatic fabrics are fabrics that are alternately or evenly blended with conductive fibers or antistatic synthetic fibers or both at equal intervals during weaving.
(2) Conductive fibers refer to all or part of the fibers made of conductive or sub-conductive materials of metals or organics. Their volume resistivity ρv～is between 104 and 109Ω/cm. The distribution of irradiated conductive components in the fibers can be divided into three types: conductive component homogeneous, conductive component covering and conductive component composite.
Most of the anti-static fabrics are made of conductive fibers, especially the composite type of conductive components, that is, composite fibers are most used.
(3) Anti-static work clothes made of conductive fibers are added to chemical fibre fabrics. Their power dissipation is based on two mechanisms: charge leakage and neutralization. When grounded, the static electricity on the fabric can be released to the earth through conductive fibers or being neutralized by the corona discharge of conductive fibers; when not grounded, it can be eliminated by the weak corona discharge of conductive fibers.

Cleaning Procedures

Sorting: After receiving the customer’s laundry to be sorted, stored them in a covered plastic box, to prevent aggravation of pollution.
Pretreatment: Take maintenance treatments to breakage, dropping buttons etc. Pre-decontamination should be carried out for the special dirt cleaning works.
Dust-free cleaning: Pretreated uniforms are cleaned by a special channel structure washing machine in the non-control area first, then they enter the control area (clean room).
Dust-free drying: Cleaned and purified uniforms are dried in the clean room by a dust-free dryer (the drying hot air used is filtered by HEPA).
Folding inspection: Fold the dry clean clothes, and the appearance inspection is carried out at the same time. If it fails to pass the inspection, it should be put back into the cleaning process to clean or be replaced.
Cleanliness test: Helmke Drum tester, which can test the number of dust particles in cleanliness grade of cleaned uniforms
ESD test: ESD performance check to ensure the anti-static performance of the cleaning garment.
Purification Packaging: Through all the inspection of the purified uniforms, after the purification packaging bag sealed packaging, it will become a qualified product.

Antistatic Standards in China

I. Standard scope:
This standard specifies the technical requirements, testing methods, inspection rules and identification of antistatic clothing.
This standard is applicable to antistatic clothing that may be used in electric shock, fire and explosion hazardous places.
The antistatic clothing defined in this standard does not apply to the power supply voltage resistence.
Standard number: GB 12014-2009
Chinese term: fáng jìng diàn fú(instead of standard number: GB 12014-1989 antistatic clothing).

II. Terms and definitions
The following terms and definitions apply to this standard.

Static protective clothing
In order to prevent the accumulation of static electricity on clothing, anti-static fabrics are used as fabrics, and the work clothes are sewn according to the prescribed style and structure.

Static protective fabric
When weaving, a fabric made of yarn blended with conductive fibers or woven with conductive filaments can also be treated and protected fabric with electrostatic properties.

Conductive fiber
All or part of the conductive material made of metal or organic materials or fibers made of static dissipative material.

Electrostatic Dissipative Material
The surface resistivity is greater than or equal to 1 x 10^5 ohms but less than 1 * 10^11 ohms.

Surface resistivity
A physical quantity representing the electrical conductivity of an object.

Point to point resistance
In a given time, the ratio of the applied current and voltage between the two electrodes on the surface of the material to the DC current flowing through them is applied.

III. Technical requirements:
1) Fabric:
– Appearance quality: It is required that the fabric should be free from damage, spots, dirt or other defects affecting the anti-static performance of the fabric.
– Testing parameters: fabric is tested by point to point resistance method, and the technical parameters are shown in the following table.

Test project
Technical requirements
Class A
Class B
Point to point resistance/Ω
1 x 10—- 1 x 10
1 x 10—- 1 x 10

2) Clothing:
– Appearance quality: there should be no defects, spots, dirt and other defects affecting the wearing performance.
– Structural style: Clothing structure should be safe and hygienic, conducive to the normal physiological requirements and health of human body; clothing should be easy to wear and adapt to the physical activities of the operation; clothing style should be simple and easy to use according to the requirement of use.
– Sewing: sewing threads in all parts are straight, neat and firm. The upper and lower tightness is suitable, no jumping needle, and the needles at the landing and landing needles should be returned.
– Test parameters: antistatic clothing is measured by charged quantity test method. The technical parameters are shown in the following table.

Test project
Technical requirements
Class A
Class B
Charge quanity/(μC per item)
<0.20
0.20 —- 0.60

3) Washing:

Anti static clothing and fabrics must be washed per the regulations before testing.

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How to Make Antistatic Shoes Work As Expected

In recent years, more and more accidents caused by static electricity, anti-static has been paid more and more attention. With the development of economy and progress of society, almost all walks of life pay more attention to it. So anti-static shoes are getting to be known by more and more people. The production and manufacturing workers will wear them to ensure the product quality and personal safety. So how can we tackle this issue properly? Let’s take a closer look:

How to Make Antistatic Shoes Work As Expected

Wearing anti-static and dust-free shoes in the right way. This can affect the safety of production and product quality in a direct way. The right methods are:

1. When using dust-free shoes, do not wear thick wool socks and insulating insoles.

2. The use of clean shoes on antistatic floor is better.

3. Professional cleaning and resistance testing should be carried out regularly in the course of use. Don’t use them if you do not pass the test.

4. Upon storing, we should make sure that we have dry and ventilated place, without direct sunlight, in order to prolong the service life.

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Take Your ESD Testing to the Next Level With 10 Tips

China has become the processing base of electronic products, in the Pearl River Delta and Yangtze River Delta Regions, a large number of electronic enterprises have been established. At present, the vast majority of ESD control job in these enterprises doesn’t follow ESD 20.20 in accordance with American standards. The ESD control work in factories is nothing more than to purchase simple ESD supplies such as anti-static work clothes and wristbands, which is far from ESD 20.20 standard.
Name
ESD Testing/Electrostatic Discharge Testing
Reference Standard
EN61000-4-2
Corresponding National Standard
GB/T 17626.2

Catalog

  • 20.20 Certification
  • 20.20 Standard
  • Related Certification
  • Applicable Industries
  • Key Benefits
  • Relevant Criteria
  • Background
  • Circumstances
  • Types
  • Models

20.20 Certification

Many enterprises are often rejected because of ESD problems after thorough preparations, when they encounter on-site audits of foreign customers. The improvement of ESD technology level is the top priority of the whole electronic industry, and the promotion and popularization of ESD system standards is an arduous task.

20.20 Standard

NSI/ESD S20.20:2007 is an accreditation project officially launched by ESD Association of United States in 2000. The association is composed of manufacturers and users of electronic components. Its main members include IBM, MOTOROLA and other companies. OEM factories or suppliers of these companies must pass ESD S20.20 accreditation in order to obtain and maintain credentials as OEM and products suppliers. Therefore, it can be considered that ESD20.20 is a buyer’s certification standard. For manufacturers of chips, electronic components, power supplies and plug converters, and displays, ESD20.20 is considered a compulsory certification in order to become a well-known brand supplier.

Related Certification

ESD certification is based on ANSI/ESD S20.20, which is to certify the ESD system of enterprises (including documents, personnel and protective facilities, etc.). ESD standard is a specific requirement for ESD protection and control system based on ISO 9001. The standards clearly stipulate the establishment of ESD system, EPA, packaging of sensitive devices, processing of production, personnel training and assessment, establishment and inspection of internal audit system, and detection methods.

Applicable Industries

Including electronics, electrics, IT and communications, etc.
1. Enterprises requiring high static electricity protection, such as those producing wafers and magnetic heads.
2. Subordinate enterprises or suppliers of well-known multinational corporations, such as IBM, Intel etc.
3. Well-known EMS enterprises of OEM and ODM.

Key Benefits

– Systematic management of anti-static electricity;
– Reduce electrostatic damage, improve product quality and pass rate;
– Reduce complaints from customers;
– Reduce/avoid duplicate check by different customers and save costs;
– Enhance customer trust and satisfaction.

Relevant Criteria

IEC 61340-5-1:2007 standard is another new international anti-static certification standard apart from ESD S20.20:2007. It was promulgated by IEC(International Electrotechnical Commission). By August 2007, this standard has been in the state of technical specifications and has not formed international standards.
IEC61340-5-1:2007 standard is an update of ESD S20.20:2007 standard. At present, European and Japanese enterprises are more inclined to IEC61340-5-1 standard certification. For ESD S20.20:2007 certified customers, the electrostatic protection system can also be easily converted according to IEC61340-5-1:2007 standard.
What are the connections and differences between ESD S20.20 and IEC 61340-5-1?
The members of IEC61340-5-1 Technical Committee for Standards(101 Committee) mostly come from ESD S20.20 standard compilers, so there is no essential difference between them. The biggest difference is that IEC61340 is an international standard, while S20.20 is a national standard of the United States. It has obtained ANSI/ESD S20.20 certification and can be freely switched to  IEC61340-5-1 certification.

Background

SNQA is the first independently recognized certification authority of ESD20.20 project in China to issue certification certificates with ESDA accreditation marks. The localized service of 10 qualified auditors in China has greatly reduced the cost of enterprise certification and simplified the procedure. It provides authoritative and professional training for customers throughout the country, and issue training certificates with ESDA accreditation marks.

Circumstances

ESD testing: a.k.a. electrostatic discharge testing.
Referential standards: EN61000-4-2, corresponding to GB/T 17626.2

Types

The test is divided into:
Contact test refers to the direct contact test for the exposed metal part of the object to be tested.
Air test refers to the direct pressure of an electrostatic spray gun on the object to be tested where the object is not in direct contact with the metal (e.g. separated by a layer of plastic).
In the standard, air discharge was suggested to be “as close as possible”, but how close is that? Therefore, manufacturer A  may follow 1mm, and manufacturer B may adopt 10mm, while manufacturer C uses 3mm, which will cause inconsistence by following the air discharge specification.

Models

Electrostatic discharge (ESD) can be divided into three types: Machinery ESD model, Furniture ESD model and Personnel ESD model. A brief explanation is as follows:
Machinery electrostatic discharge may occur in the automated control process, because of the friction between insulated metal parts and insulators in the automated machine, or the static electricity generated by the friction of insulating liquid or high-voltage gas, when the energy accumulates to a certain extent, it discharges nearby.
Furniture electrostatic discharge usually occurs when metal furniture rubs against insulating objects, such as pulling furniture on carpets or plastic floors, or when people stand up from chairs, static electricity is generated by friction.
Personnel electrostatic discharge is static electricity generated by human action friction, such as when we walk on the carpet wearing rubber shoes, the carpet carries positive charge and  rubber shoelaces carry negative charge because of friction. Now, the sole of human foot will be induced and positively charged, while the upper body will be negatively charged. If we touch semiconductor electronic components by hand at that time, the components will be damaged.
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WootC | Anti-Static, ESD Shoes & Apparels | Suzhou | Shanghai | Chengdu
Phone: +86 18217522696  | Email: [email protected]

Located in  Suzhou, Shanghai and Chengdu, wootC dedicates itself in manufacturing anti-static, ESD clothing, shoes etc. since 2008. We’ve cooperated with distributors & suppliers from all over the world, including but not limited to Mainland China, Malaysia, UK, US, Saudi Arabia.

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