Solvent resistent acrylic resin and process for producing the same
AssigneeAsahi Kasei Kogyo Kabushiki Kaisha
InventorsMakoto Honda, Kohe Ozawa, Kazuhiro Hosoya, Jiro Kurita
Life of this patent
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Abstract
An acrylic resin having resistance to crazing or crack formation when brought into contact with an organic solvent may be prepared by polymerizing or copolymerizing a monomer or monomers comprising (1) 50 to 100 wt. % of methyl methacrylate and (2) 0 to 50 wt. % of at least one monomer selected from the group consisting of an acrylic ester and a methacrylic acid ester, and adding a chain transfer agent after initiation and prior to completion of the polymerization. The acrylic resins have an intrinsic viscosity of 0.028 to 0.117 liters per gram, and a ratio of weight-average molecular weight to number-average molecular weight of 2.3 to 6.0.
Claims9
A process for producing an acrylic resin having an intrinsic viscosity of about 0.028 to about 0.117 l/g and a weight-average molecular weight to number-average molecular weight ratio, measured by gel permeation chromatography, of about 2.3 to about 6.0, which process comprises polymerizing at a temperature range of from 40.degree. C. to 170.degree. C., using a polymerization initiator:
- A. about 50 to 100 wt. % of methyl methacrylate, and
- B. 0 to about 50 wt. % of at least one monomer selected from the group consisting of acrylic ester monomer and methacrylic ester monomer, said acrylic ester monomer comprising the reaction product of an alkyl alcohol having 1 to 8 carbon atoms and acrylic acid and said methacrylic ester comprising the reaction product of an alkyl alcohol having 2 to 12 carbon atoms and methacrylic acid;
- and
- adding, after initiation of polymerization, about 0.01 to about 5 wt. %, based on the weight of monomer, of a chain transfer agent comprising at least one compound selected from the group consisting of alkylmercaptans containing 4 to 18 carbon atoms;
- esters of thioglycolic acid and an alkyl alcohol having 1 to 12 carbon atoms;
- said chain transfer agent being added at a stage where the degree of conversion to the polymer is about 10 to about 60%.
Dependencies are inferred from the claim text.