Resin composition for capstock

• US 20020177658A1
• Filed: 12/20/2000
• Published: 11/28/2002
• Est. Priority Date: 12/20/2000
• Status: Active Grant

• Current Assignee: Kaneka North America LLC
• Original Assignee: Kaneka Corporation
• Inventors: Tajima, Kazuhisa, Sugaya, Takahiko, Nishimura, Riichi
• Granted Patent: US 6,555,245 B2
• Time in Patent Office: Days
• US Class Current: 525/85
• CPC Class Codes: C08F 220/14 Methyl esters , e.g. methyl (meth)acrylate
• CPC Class Codes: C08F 220/1804 C4-(meth)acrylate, e.g. butyl (meth)acrylate, isobutyl (meth)acrylate or tert-butyl (meth)acrylate
• CPC Class Codes: C08F 285/00 Macromolecular compounds obtained by polymerising monomers on to preformed graft polymers
• CPC Class Codes: C08L 2666/04 Macromolecular compounds according to groups C08L7/00 - C08L49/00, or C08L55/00 - C08L57/00; Derivatives thereof
• CPC Class Codes: C08L 51/003 grafted on to macromolecular compounds obtained by reactions only involving unsaturated carbon-to-carbon bonds C08L51/04, C08L51/06 take precedence
• CPC Class Codes: Y10T 428/31928 Ester, halide or nitrile of addition polymer

Abstract

An acrylic resin composition suitable for the preparation of capstock for siding panels and having excellent impact resistance, weatherability and processability and a low gloss, which comprises 30 to 100% by weight of an impact modifier having a multilayer structure and 0 to 70% by weight of a methyl methacrylate homopolymer or copolymer and whose MFI (melt flow index measured according to ASTM D-1238 at 230° C. and a load of 3.8 kg) is no more than 0.2 g/10 minutes.

Claims

1. A resin composition suitable for extrusion to prepare a capstock using a multi-manifold die comprising 100 to 30 parts by weight of an impact modifier having a multilayer structure and 0 to 70 parts by weight of a methyl methacrylate polymer comprising 50 to 100% by weight of methyl methacrylate and 50 to 0% by weight of a copolymerizable monomer, the total of said impact modifier and said methyl methacrylate polymer being 100 parts by weight and said composition having an MFI (melt flow index measured according to ASTM D-1238 at 230°

C. and a load of 3.8 kg) of not more than 0.2 g/10 minutes.

2. The composition of claim 1, which comprises 20 to 60 parts by weight of said methyl methacrylate polymer and 80 to 40 parts by weight of said impact modifier, the total thereof being 100 parts by weight.

3. The composition of claim 1, wherein said methyl methacrylate polymer comprises 5 to 90% by weight of a methyl methacrylate polymer having a molecular weight of not less than 500,000 and 95 to 10% by weight of a methyl methacrylate polymer having a molecular weight of less than 500,000.

4. The composition of claim 1, wherein said impact modifier is a polymer having two layer structure prepared by polymerizing 50 to 15 parts by weight of a monomer mixture comprising 50 to 100% by weight of a (meth)acrylic ester and 50 to 0% by weight of a copolymerizable monomer in the presence of 50 to 85 parts by weight of a crosslinked acrylic rubber.

5. The composition of claim 1, wherein said impact modifier is a polymer having three layer structure prepared by polymerizing 30 to 60 parts by weight of a monomer mixture comprising 50 to 99.5% by weight of an alkyl acrylate, 50 to 0% by weight of a copolymerizable monomer and 0.1 to 5% by weight of a crosslinking monomer in the presence of 10 to 40 parts by weight of a polymer prepared by polymerization of 80 to 99.5% by weight of methyl methacrylate, 20 to 0% by weight of a copolymerizable monomer and 0.1 to 5% by weight of a crosslinking monomer to give a two-layered polymer, and then polymerizing 10 to 60 parts by weight of a monomer mixture comprising 50 to 100% by weight of a (meth)acrylic ester and 50 to 0% by weight of a copolymerizable monomer in the presence of said two-layered polymer.

6. The composition of claim 1, wherein said capstock is a capstock for a siding panel made of polyvinyl chloride.

7. A siding panel obtained by extrusion using the composition of claim 1 as a capstock and a vinyl chloride resin as a substrate.