Styrene processing aids

Acrylics. Acetone is converted via the intermediate acetone cyanohydrin to the monomer methyl methacrylate (MMA) [80-62-6]. The MMA is polymerized to poly(methyl methacrylate) (PMMA) to make the familiar clear acryUc sheet. PMMA is also used in mol ding and extmsion powders. Hydrolysis of acetone cyanohydrin gives methacrylic acid (MAA), a monomer which goes direcdy into acryUc latexes, carboxylated styrene—butadiene polymers, or ethylene—MAA ionomers. As part of the methacrylic stmcture, acetone is found in the following major end use products acryUc sheet mol ding resins, impact modifiers and processing aids, acryUc film, ABS and polyester resin modifiers, surface coatings, acryUc lacquers, emulsion polymers, petroleum chemicals, and various copolymers (see METHACRYLIC ACID AND DERIVATIVES METHACRYLIC POLYMERS). 

Processing aid-80, a masterbatch in the form of pressed crumb consisting of an 80 20 blend of crosslinked to ordinary natural rubber. The correct proportions of vulcanised latex and field latex are blended, coagulated and the resulting crumb pressed into 100 lb bales. The use of PA 80 confers Superior Processing properties on any natural or styrene-butadiene rubber with which it may be mixed. See Superior Processing Rubber. 

A typical tire rubber formulation for tire tread will contain various rubbers, mainly styrene-butadiene (50%) and cA-polybutadiene (12%), various processing aids (2%), softeners (3%), vulcanizing agent (mainly sulfur 1%), accelerators, and reinforcing filler (namely carbon black 30%) so that by bulk, carbon black is the second most used material. 

The possibilities for copolymers with specialized performance characteristics depend on the ability to effect copolymerization with the other monomer. To date efforts to effect copolymerization with such monomers as styrene and butadiene have been unsuccessful (r2=35 vs. rj =0.067 for styrene, and r2=8.8 vs. r =0.035 for butadiene). The possibilities nevertheless exist for modifying the basic polymer to effect such desirable properties as cross-linking, improvement in impact resistance, compatibility with processing aid modifiers, and UV stability. 

Naugard . [Uniroyal Uniroyal Chem. Ltd.] Antioxidant, metal derivator, processing aid, polymerization inhibitor, stabilizer for adhesives, thermoplastic and thermoset polymers styrene inhibitors. 

As stated previously, styrene-diene triblock copolymers are the most important category of thermoplastic elastomers. Unlike most other TPEs, they can be blended with large quantities of additives without a drastic effect on properties. In almost all applications, the actual triblock copolymer content is less than 50%. Oils are used as a processing aid and do not result in a significant loss of properties if the polystyrene domains are not plasticized. For this reason, naphthalenic oils are preferred. The use of inert fillers such as clays or chalks reduces the cost of the final material. Unlike conventional rubbers, inert fillers do not have a substantial effect on the mechanical properties of TPEs. Thermoplastics such as polyethylene or polypropylene are also used to improve the solvent resistance and can increase the upper service temperature. Polystyrene homopolymer is used as a processing aid, which also increases the hard phase weight fraction and causes the material to stiffen. 

Uses Externai iubricant, processing aid, siip agent, antibiocking agent, scuff/mar resist, aid in styrenics, poiyoiefins, TPOs, for formuiation of emuisions, textiie finish softeners, floor, auto, and iiq. soiv.-based poiishes... 

Lubral 2522 Lubral 2544 Lubral 5005 Lubral 5011 StruMol PEH-100 processing aid, styrenics... 

Uses Catalyst in polyethylene crosslinking, styrene polymerization, polyester resins crosslinking agent for plastics, rubber rheology and processing aid for PP initiator in prod, of propylene homopolymer for use in food pkg. 

Tetrabromodipentaerythritol CAS 109678-33-3 Synonyms TBDPE Empincai CioHisBr403 Properties Powd. m.w. 505.87 m.p. 75-82 C Toxicology LD50 (oral, rat) > 5000 mg/kg Uses Reactive flame retardant, processing aid for plastics, PP, styrene copolymers, unsat. polyester resins... 

Alkane sulfonates are applied in a widespread manner in emulsion polymerization. They are used as processing aids, in particular in the emulsion polymerization of vinyl chloride, vinyl acetate, styrene and acrylonitrile. Because they possess no double bonds, alkane sulfonates do not act as radical chain stoppers. Well-known lattices derived from emulsion polymerization are poly(vinyl chloride), ethylene-vinylacetate copolymers, polyacrylates, and butadiene and chloroprene rubbers. Alkane sulfonates also offer good stabilizing effects in lattices against coagulation by fillers. 

Process aids are used chiefly in polyethylene (LLDPE, LDPE and HOPE) and in PVC. Some metallocene PP grades have a narrow molecular weight distribution and also benefit from process aids. Certain styrene polymers, polyamides, acrylics and thermoplastic elastomers may also benefit. 

Acrylic process aids include copolymers of methyl methacrylate (MMA) and other types of acrylic monomers like ethyl acrylate, butyl acrylate and butyl methacrylate. Some even include styrene monomer, imparting to the polymer an antisticking effect due to its limited compatibility with PVC. The functions of these lubricating process aids are not described in this chapter. 

Methyl styrenes Standard processing aids for PVC impact modifiers... 

Methyl butadiene styrene (MBS) and acrylic (PMMA), which are used widely as impact modifiers for PVC and engineering resins, also function as processing aids, for rigid and semi-rigid processes and applications, such as blow moulding, calendering, profile extrusion, and injection moulding of technical parts. Some types can also be tailored to suit specific requirements. 

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