The importance of anti-static work clothes
Anti-static work clothes are mainly used in electronics, optical instruments, pharmaceuticals, microbiological engineering, precision instruments, petroleum, petrochemical, chemical, refining and other industries. Special work clothes with dust-free and anti-static properties are generally embedded with conductive yarns. Synthetic fabric. Among them, the anti-static clothing conforming to GB12014-2009 is sewn with anti-static fabric as the fabric in order to prevent the accumulation of static electricity in the clothes. It is suitable for static-sensitive places or places with fire or explosion hazards. The production process of the anti-static fabric used is mainly to mix in all or part of the anti-static fiber or anti-static synthetic fiber made of metal or organic conductive materials at approximately equal intervals or evenly during weaving, or a mixture of the two. .
Hazard of static electricity from clothing
In normal production activities, between the clothing worn by the operator and the surface of the external medium (such as worktops, chair surfaces, tools, appliances, etc.), between layers of clothing, underwear and skin, until the soles of the shoes and the ground when walking Between the plateaus, clothing and shoes are charged due to frequent contact, separation and friction. The electrostatic charge on the part of clothing and shoes gradually dissipates to the entire surface according to the law of charge dissipation on the medium, and a certain static voltage on the clothing is formed when equilibrium is reached. Of course, because the human body itself is a good conductor, the charging of clothing will cause the skin of the human body to be charged due to electrostatic induction, and a certain static voltage will also be formed. Therefore, for the operator, there are two possible discharge channels; one is the discharge between the fingertip (skin) and the grounding conductor, and the other is the discharge between the work clothes and the grounding conductor. Both of these discharges may cause damage to electrostatic sensitive devices.
When the human body is performing various activities, the static voltage value on the clothing has greatly exceeded the electrostatic discharge damage threshold of many electrostatic sensitive devices, so the sensitive devices may be damaged when they touch or approach these components. It is generally believed that wearing cotton overalls can prevent the accumulation of static electricity in clothing. Actually, this view is one-sided, and can only be basically realized when the relative humidity of the air is higher than 50%; and when the relative humidity is relatively low, the charge of pure cotton products increases significantly , Experiments show that when the relative humidity is lower than 30%, the charge amount of pure cotton fabric is equivalent to that of polyester; and when the relative humidity is lower than 20%, the charge amount of cotton fabric is even higher than that of some chemical fiber fabrics. Therefore, in dry climates, we cannot expect to use pure cotton products to eliminate clothing static electricity hazards under any circumstances. Therefore, in order to effectively prevent the electrostatic discharge hazards of human body static electricity, the operator must wear anti-static work clothes
Principle of anti-static clothing
Anti-static work clothes refer to work clothes sewn with anti-static fabric as the fabric to prevent the accumulation of static electricity on clothing. The anti-static fabric is a fabric made by mixing conductive fibers or anti-static synthetic fibers or both at roughly equal intervals or evenly during weaving. Conductive fiber refers to the general term for fibers made of conductive materials or sub-conductive materials that are wholly or partly made of metal or organic matter, and its volume resistivity ρv is between 104 and 109Ω·cm. According to the distribution of conductive components in the fiber, conductive fibers can be divided into three types: uniform conductive component, conductive component covering type and conductive component composite type. At present, most anti-static fabrics are made of conductive fibers, especially the conductive component composite type, that is, composite fibers are used the most. The anti-static work clothes made by adding conductive fibers to chemical fiber fabrics are based on two mechanisms of leakage and neutralization of electric charges. When grounded, the static electricity on the fabric is neutralized by the corona discharge of the conductive fiber, and can also be discharged to the ground through the conductive fiber; when it is not grounded, the weak corona discharge of the conductive fiber is used to dissipate the static electricity. Practice shows that anti-static work clothes can effectively suppress static electricity in clothing and eliminate or reduce the hazards of electrostatic discharge.