Processing aid for foam molding use and vinyl chloride resin composition containing the same

• US 6,391,976 B1
• Filed: 12/04/2000
• Issued: 05/21/2002
• Est. Priority Date: 02/24/1998
• Status: Expired due to Term

• Current Assignee: Mitsubishi Chemical Corporation (Mitsubishi Chemical Group Corp.)
• Original Assignee: Mitsubishi Rayon Company Limited (Mitsubishi Chemical Holdings Corporation)
• Inventors: Takei, Seiji, Naka, Naho, Wakabayashi, Shigeo, Nakata, Akira
• Primary Examiner(s): Boykin, Terressa M.
• Application Number:
  US09/622,055
• Time in Patent Office: 533 Days
• Field of Search: 525/239
• US Class Current: 525/239
• 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: C08J 2327/06 Homopolymers or copolymers of vinyl chloride
• CPC Class Codes: C08J 2433/00 Characterised by the use of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides, or nitriles thereof; Derivatives of such polymers
• CPC Class Codes: C08J 9/0061 characterized by the use of several polymeric components
• CPC Class Codes: C08J 9/103 Azodicarbonamide
• 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 27/06 Homopolymers or copolymers of vinyl chloride
• CPC Class Codes: C08L 33/10 Homopolymers or copolymers of methacrylic acid esters
• CPC Class Codes: C08L 33/12 Homopolymers or copolymers of methyl methacrylate

Abstract

A processing aid (B) for foam molding use which comprises a powdered copolymer composed of 50 to 80% by weight of methyl methacrylate, 20 to 50% by weight of an alkyl methacrylate having an alkyl group of 3 to 5 carbon atoms, and 0 to 20% by weight of other copolymerizable monomers, the copolymer having a reduced viscosity (η_sp/c) of 4 to 8. Use of this processing aid permits vinyl chloride resins to be kneaded efficiently and imparts an increased melt strength thereto, so that fine and uniform foamed cells can be formed and, moreover, a high foaming ratio and an attractive molding appearance can be achieved.

Claims

1. A processing aid (B) for foam molding use which comprises a powdered copolymer obtained by the polymerization of 50 to 80% by weight of methyl methacrylate, 20 to 50% by weight of an alkyl methacrylate having an alkyl group of 3 to 5 carbon atoms, and 0 to 20% by weight of other copolymerizable monomers, the copolymer having a reduced viscosity (η

_sp/c) of 4 to 8.

2. A processing aid (B) for foam molding use as claimed in claim 1 which has been formed into a powder by spray drying.

3. A processing aid (B) for foam molding use as claimed in claim 1 or 2 wherein less than 50% by weight of the powder comprises particles whose inner part has fused into a homogeneous state.

4. A vinyl chloride resin-based foam molding composition comprising 100 parts by weight of a vinyl chloride resin (A) and 1 to 25 parts by weight of a processing aid (B) for foam molding use as claimed in claim 1.

5. A vinyl chloride resin-based foam molding composition as claimed in claim 4 wherein the vinyl chloride resin (A) has an average degree of polymerization of 300 to 5,000.

6. A foam-molded product formed from a vinyl chloride resin-based foam molding composition as claimed in claim 5.

7. A vinyl chloride resin-based foam molding composition comprising 100 parts by weight of a vinyl chloride resin (A) and 1 to 25 parts by weight of a processing aid (B) for foam molding use as claimed in claim 2.

8. A vinyl chloride resin-based foam molding composition comprising 100 parts by weight of a vinyl chloride resin (A) and 1 to 25 parts by weight of a processing aid (B) for foam molding use as claimed in claim 3.