| Choice of modified plastics additives | |
| Release time£º2016/12/18 | |
Plastic formula design looks very simple, but it contains a lot of internal connection, in order to design a high performance, easy processing, low price formula, there are many factors to consider when choosing a additives, is put forward for reference of the following factors:
1. According to the purpose to use additives
As to achieve the purpose of choosing appropriate fertilizer varieties, adding the additives should be able to give full play to its expected effect, indicators and reach regulation. Regulation indicators generally the national standards, international standards for the products, or to the performance requirements of customers.
A range of concrete additives as follows:
Toughening, elastomer, thermoplastic elastomer and rigid toughening materials.
Enhancement - choose glass fiber, carbon fiber, whisker and organic fibers.
Flame retardant - bromide (ordinary bromide bromine series and environmental protection department), phosphorus, nitrogen, nitrogen/phosphorus compound class expansion type flame retardant, antimony trioxide, hydrated metal hydroxide.
Antistatic, all kinds of antistatic agent.
Conductive carbon (carbon black, graphite, carbon fiber, carbon nanotubes), metal fiber and metal powder, metal oxide.
Magnetic ferrite magnetic powder, rare earth magnetic powder including samarium cobalt (SmCo5 or Sm2Co17), NdFeB classes (NdFeB), samarium iron nitrogen (SmFeN), aluminum nickel;
Thermal conductivity, metal fiber and metal powder, metal oxides, nitrides and carbides; Carbon materials such as carbon black, carbon fiber, graphite and carbon nanotubes; Semiconductor materials such as silicon and boron.
Heat, glass fiber, inorganic filler, heat resistant agent such as place of maleic imide and beta crystal nucleating agent.
Transparent nucleating agent, alpha crystal nucleating agent for PP of sorbitol series Millad 3988 works best.
Wear-resisting, graphite, molybdenum disulfide, copper powder, magnetic powder, such as cobalt like three categories.
Insulation - the calcined kaolin.
Block, mica, montmorillonite, quartz and so on.
2. Selective agent on resin
Red phosphorus flame retardants for PA, PBT, PET effective;
Nitrogen containing oxygen flame retardants for effective, such as PA, PBT, PET, etc.;
Effect of nucleating agent on the copolymerization polypropylene;
Glass fiber heat resistant modification of crystalline plastics effect is good, the amorphous type plastic effect is poor;
Carbon black filled conductive plastics, good effect in the crystalline resin.
3. The assistant form is different, have distinction
The same kind of additives, the composition of its form is different, had a great influence on its role in modification.
(1) the shape of the additives
Fibrous additives enhancement effect is good.
Fertilizer available length to diameter ratio of degree of fibrosis, said the L/D, the greater the effect, the better, that is why we add glass fiber from the vent to join.
Molten state than powder is helpful to keep the length to diameter ratio, reduce broken fiber.
Globular additives of toughening effect is good, high brightness.
Barium sulfate for typical globular additives, so choose barium sulfate high gloss PP filler, small rigid toughening barium sulfate is also available.
(2) fertilizer particle size
A. auxiliary particle size effect on the mechanical properties:
The smaller the particle size, tensile strength and impact strength of filling materials, the more beneficial.
B. fertilizer particle size effect on the properties of flame retardant:
The smaller the particle size of flame retardant, flame retardant effect is better. Such as hydrated metal oxides and antimony trioxide granularity is smaller, the less they reach the same flame retardant effect of addition amount.
C. auxiliary particle size effect on color:
The smaller the particle size of the colorant, the higher the tinting strength, hiding power, the more strong, colour and lustre is uniform. But the size of the colorant is not as small as possible, there is a limit value, and the performance of the different limit value is different. For tinting strength, azo colorants limit of particle size of 0.1 mu m, phthalein wellknown class colorants the limits of the particle size of 0.05 microns. For covering power, colorant about the limits of the particle size of 0.05 mu m.
D. auxiliary particle size effect on the properties of conductive:
Carbon black, for example, its granularity is smaller, more easy to form a mesh conductive pathways, achieve the same effect of conductive to join the amount of carbon black. But as colorant, particle size also has a limit value, the particle size is too small easy to gather and difficult to disperse, but effect is not good.
(3) the surface treatment of AIDS
Additives and the compatibility of resin, which ensures that additives and resin in the structure of thought, ensure the completion of design index, guarantee its effect within the service life of the persistent, extraction resistance, resistance to migration and precipitation. Like most recipes require additives and resin evenly dispersed, formula of barrier property wants additives in the resin level distribution. In addition to outside a few additives such as surfactants, good compatibility with resin is the key to exert its efficacy and improve the quantity. Therefore, you must try to improve or improve its compatibility, such as compatilizer or coupling agent used for surface activation treatment, etc.
The surface of all classes of inorganic additives after processing, the modification effects will improve. Especially in the packing, there are other glass fiber, inorganic flame retardants, etc.
Surface treatment is given priority to with coupling agent and compatibilizer, concrete such as silane coupling agent, titanate and aluminate ester, compatibilizer for maleic anhydride grafted polymer resin.
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