Standard Specification and standard of plastic ABS flame retardant board

1 fire safety ABS flame retardant board

ABS flame retardant board is classified as HB according to UL94. ABS ignites faster when it is on fire, and releases a lot of poisonous gas and black smoke from exhaust pipe, which is unfavorable for specific application. With the improvement of scientific and technological innovation and quality of life, people's awareness of prevention is becoming stronger and stronger. Countries all over the world have clearly put forward strict fire safety and flame retardant regulations for plastic materials used in cars, engineering buildings, electrical products, office equipment, etc., and formulated relative standards and norms. Therefore, the scientific research on ABS flame retardant board has a very important practical significance.

There are three ways to reduce the flammability of ABS epoxy resin

1. Flame retardant polymer was blended with ABS, such as CPE and PVC;

2. For the current ABS flame retardant board, organic chemical modification materials are developed, such as adding tribromophenylethylene as the fourth single material to produce four component ABS;

3. According to the general way to add flame retardants to ABS, including inorganic flame retardants (such as MoO3) and organic chemical flame retardants (such as halogen chemicals, phosphorus flame retardants). Flame retardant has high efficiency of flame retardant, but other characteristics will not be very good (such as embrittlement, cost increase). ABS flame retardant board, an organic chemical modified material, must have a special processing process, which is more complicated. The third way has a balance between cost and characteristics, and has a better coordination ability in the design of intelligent raw materials. At present, the flame retardant modification of ABS raw materials is dominated by high efficiency halogen-containing flame retardant.

2 high temperature (heat resistant) ABS flame retardant board

The thermal expansion temperature of high temperature resistant ABS epoxy resin is generally 90 ~ 105 ℃, which has excellent heat resistance, ductility and flowability. It can be made of small door, rear tire cover side beam, control panel, etc. it is used in household appliances industry, such as microwave oven heating, electric cooker, hair dryer, etc. The heat resistance of ABS can be improved by reducing the moisture content of vulcanized rubber and increasing the moisture content of San and PE. However, the development and design of high temperature resistant ABS with high temperature resistant modifier or single modifier is more concerned.

Introducing α - methylstyrene (MS), maleic anhydride (MA) and maleimide (MI) into ABS epoxy resin can improve the heat resistance of ABS. There are two key ways

1. Taking MS and MI as the third single mixture with styrene and PE to improve the stiffness and TG of conventional epoxy resin. The heat resistance of the prepolymer of Ma and an is better than that of San with the same water content of an, and the Vicat softening temperature is 123 ℃ and 103 ℃ respectively. Their acid resistance and process properties are similar, and their manufacturing methods are also universal. According to MS raw material hue ratio according to styrene raw material yellow. In the process of manufacturing, only a part of styrene was replaced by MS to obtain smsan prepolymer. The proportion of substitution lies in the regulation of heat resistance.

2. Styrene maleic anhydride prepolymer (SMA) or styrene maleimide prepolymer (SMI) with better heat resistance were added to ABS epoxy resin as blending components. The Vicat softening point temperature of SMA reaches 150 ℃. However, SMA is not stable at higher temperature. It will release carbon dioxide, so it must be released to keep it stable and stable, and can be produced and processed below 260 ℃, otherwise there will be radioactive lines in the production. SMA can be stabilized by adding 1% hindered phenolic antioxidant and thioester synergist. SMI can be used in places where the heat resistance of SMA and MS must be higher than that of SMA. The production process of the mixture of styrene and MI is the same as that of San. SMA can react with ammonia or amine to produce SMI. SMI has good heat resistance at high temperature and does not cause radioactive lines.

3 anti static ABS flame retardant board

The resistor characteristic of San should be a little less than that of PS, but it still has enough dielectric strength. The surface electrostatic effect of ABS flame-retardant board causes dust absorption, difficult mold out, electrostatic discharge and other problems in production, processing, transportation and application. Therefore, ABS crafts must have a certain conductivity to avoid internal charge and discharge, and even shield the external interference signal to high-precision electronic components. Adding antistatic agent can avoid or eliminate the electrostatic effect, which is the key way to prepare anti-static ABS flame retardant board.

Antistatic agent can be added before or in the whole process of ABS flame retardant board production and processing. According to the addition method, the types of antistatic agents are as follows:

(1) The external antistatic agent is applied to the surface of ABS crafts in the form of water or alcohol solution, and the most common application is quaternary ammonium salt. Quaternary ammonium salt can reduce the production of surface resistor, but it is easy to be removed in the whole process of production, application and cleaning, so it is widely used to avoid dust deposition on display components and other short-term main purposes.

(2) The inner antistatic agent is added in the production and processing of ABS, with a small amount (0.1% ~ 3%), which is compatible with ABS at a certain level. The internal antistatic agent is divided into mobile antistatic agent and Yongjiu antistatic agent. The mobile antistatic agent is ionic or ionic surfactant. The hydrophobic part is limited to be compatible with ABS flame retardant board, and the hydrophilic part can absorb water to improve the surface conductivity after being transferred to the surface inside ABS flame retardant board. After the antistatic agent on the surface is removed, the internal antistatic agent is still transferred to the surface until it is completely consumed, so the application time is longer than that of the external electrostatic induction agent. Yongjiu antistatic agent does not transfer and contains high conductivity fillers (such as carbon black, metal coated composites, stainless steel wire), water absorbent fiber materials (such as polyoxybutadiene prepolymer) and conductive fiber materials (such as polypropylene, polythiophene). Among them, the absorbent fiber material is low, the key is used in office system machinery and equipment. Conductive fillers are mainly used to indicate the color tone and clarity, as well as the electronic device industry.