2013年8月28日星期三

PVC impact modifier types Introduction

PVC impact modifier and sometimes also from the plasticizing effect , it can also be seen as a plasticizer for PVC resins and impact modifiers are the following : ( 1 ) chlorinated polyethylene (CPE ) is the iron oxide black  use of HDPE in the water phase of the powdery product by suspension chlorination , so as to increase the degree of chlorination of HDPE original crystals become amorphous elastomer. Used as a toughening agent C? E, containing 25-45 % amount is generally C1 . CPE wide source of low price, in addition to a toughening effect , but also has a cold resistance, weather resistance , flame resistance , and chemical resistance . At present in China is dominated by CPE impact modifiers , especially in the production of PVC pipes and profiles , most plants use CPE. Generally added in an amount of 5-15 copies. CPE can be used in conjunction with other plasticizer , such as rubber , EVA , the effect is better, but even in aging rubber additives .
(2) ACR is methyl methacrylate , acrylate monomers , ACR is best developed in recent years, impact modifiers , which can increase the impact strength of the material several times. ACR core-shell structure is an impact modifier , methyl methacrylate - ethyl acrylate composition of the shell polymer , crosslinked acrylic or butyl rubber elastic body is formed as the core of the particle distribution of the inner segment . Particularly suitable for outdoor use PVC plastic products, impact-modified PVC plastic window profiles used in the ACR as impact modifiers and other modifiers processing performance compared with the smooth surface, good aging resistance , high strength welding angle characteristics, but the price CPE, high 1 /3. Common foreign brands such as K-355, the general amount 6-10 copies. The current domestic production of the manufacturers ACR impact modifier fewer manufacturers use less.
(3) MBS is methyl methacrylate , butadiene and styrene copolymer of the monomers . MBS between the solubility parameter of 94-9.5 , with PVC solubility parameter close, so when the good compatibility with PVC , its most important feature: After adding PVC products can be  tio2 anatase made transparent . Generally added in PVC 10-17 parts of PVC , the impact strength can be increased 6-15 times, but the MBS in amount more than 30 parts , PVC impact strength decreased. MBS itself has a good impact resistance , good transparency , light transmission rate of 90 %, and to improve the impact resistance while other properties of the resin , such as tensile strength , elongation at break little effect . MBS higher prices , often with other impact modifiers, such as EAV, CPE, SBS , etc. and use . MBS poor heat resistance , weather resistance , not suitable for long-term outdoor use made ​​products, generally do not do plastic doors and windows profile production impact modifiers .
(4) SBS is a styrene -butadiene- styrene block copolymers, also known as thermoplastic rubber, thermoplastic elastomer part , the structure can be divided into star and line two kinds. SBS ratio of styrene to butadiene is mainly 30 /70, 40 /60 , 28 / 72 , 48/ 52 several. Mainly used as HDPE, PP, PS impact modifiers in an amount 5-15 parts . SBS primary role is to improve the low temperature impact resistance . SBS poor weather, not suitable for long-term outdoor use made ​​products.
(5) ABS is a styrene ( 40% -50 % ) , butadiene ( 25% -30 % ) , acrylonitrile ( 25% -30 % ) terpolymer used mainly plastic , PVC is also used impact modified , low-temperature impact modifiers also very effective. ABS is added in an amount of 50 parts , PVC , the  PVC heat stabilizer impact strength can be quite pure ABS . ABS is generally added in an amount of 5-20 parts , ABS poor weather , unsuitable for long-term outdoor use products, generally do not do plastic doors and windows profile production impact modifiers .
(6) EVA is an ethylene vinyl acetate and acid copolymer, vinyl acetate changed into a crystalline polyethylene , vinyl acetate content of a large difference , and the different refractive index EVA and PVC , transparent products is difficult to obtain , therefore , often the EVA resin and used with other impact . EVA dosage of 10 parts or less .

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