Impact strength modifiers for polyvinyl chloride resin and method of preparing them
AssigneeLG Chem, Ltd.
InventorsYoon Ho Kim, Wonsuk Jang, Geon Soo Kim
Life of this patent
Estimating the term…
Abstract
Provided are a rubber latex having a multi-layer structure, wherein an inner-layer rubber latex has a refractive index greater than that of an outer-layer rubber latex, a graft copolymer prepared from the rubber latex, a polyvinyl chloride (PVC) resin blend containing the graft copolymer, and a method of preparing the rubber latex. The PVC resin blend containing the graft copolymer including the rubber latex according to the present invention has improved color property and low-temperature impact strength than conventional PVC resins.
Claims12
A rubber latex formed from a copolymer of a conjugated diene, an ethylenically unsaturated aromatic compound and optionally, a crosslinking agent, said crosslinking agent being selected from the group consisting of divinylbenzene, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, 1,3-butylene glycol dimethacrylate, aryl methacrylate, and 1,3-butylene glycol diacrylate,
- wherein the rubber latex has a multi-layer structure with an inner-layer rubber latex having a refractive index of 1.54-1.59 and an outer-layer rubber latex having a refractive index of 1.51-1.54, and
- wherein the monomeric ratio averaged over the entirety of said rubber latex is about conjugated diene :
- (ethylenically unsaturated aromatic compound + crosslinking agent) =3:1 by weight,
- wherein a difference between the refractive index of the inner-layer rubber latex and that of the outer-layer rubber latex is greater than or equal to 0.0222.
A graft copolymer prepared by performing graft emulsion polymerization of 5-50% by weight of at least one monomer selected from the group consisting of alkyl (meth)acrylate and an ethylenically unsaturated aromatic compound onto 50-95% by weight of a rubber latex having a multi-layer structure, said weight percentages being based on the weight of the ungrafted rubber latex, wherein an inner-layer rubber latex has a refractive index greater than that of an outer-layer rubber latex, and wherein:
- (a) the rubber latex is a copolymer of a conjugated diene monomer, an ethylenically unsaturated aromatic compound, and optionally a crosslinking agent, said crosslinking agent being selected from the group consisting of divinylbenzene, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, 1,3-butylene glycol dimethacrylate, aryl methacrylate, and 1,3-butylene glycol diacrylate;
- (b) the rubber latex is a conjugated diene monomer with at least one monomer selected from the group consisting of butadiene, isoprene, and chloroisoprene,
- (c) the ethylenically unsaturated aromatic compound of the rubber latex is at least one compound selected from the group consisting of styrene, alpha-methylstyrene, isopropenylnaphthalene, vinylnaphthalene, styrene having at least one of hydrogens on a benzene ring substituted with a C1-C3 alkyl group, and styrene having at least one of hydrogens on a benzene ring substituted with a halogen;
- (d) the inner-layer rubber latex has a refractive index of 1.54-1.59 and the outer-layer rubber latex has a refractive index of 1.51-1.54;
- and
- (e) the relative monomeric ratio averaged over the entirety of said rubber latex is about conjugated diene :
- (ethylenically unsaturated aromatic compound + crosslinking agent) =3:1 by weight,
- (f) a difference between the refractive index of the inner-layer rubber latex and that of the outer-layer rubber latex is greater than or equal to 0.0222.
A polyvinyl chloride (PVC) resin blend comprising 1-20% by weight of the graft copolymer of any one of claims 4-6 and 80-99% by weight of a PVC resin.
A method of preparing a rubber latex, comprising:
- emulsion polymerizing 25-75% by weight of a monomer mixture of a conjugated diene monomer, an ethylenically unsaturated aromatic compound and a crosslinking agent to form an inner-layer rubber latex;
- and
- then emulsion polymerizing 25-75% by weight of the remaining monomer mixture to the inner-layer rubber latex to form an outer-layer rubber latex,
- wherein the inner-layer rubber latex has a refractive index of 1.54-1.59 and the outer -layer rubber latex has a refractive index of 1.51-1.54 and
- the relative monomeric ratio combined over the two emulsion polymerization stages is about
- conjugated diene :
- (ethylenically unsaturated aromatic compound + crosslinking agent) =3:1 by weight
- wherein a difference between the refractive index of the inner-layer rubber latex and that of the outer-layer rubber latex is greater than or equal to 0.0222.
Dependencies are inferred from the claim text.