Thermoplastic acrylic resin composition

摘要

Provided is a thermoplastic acrylic resin composition comprising a methacrylic resin (A) and a polyvinyl acetal resin (B) obtained by acetalizing a polyvinyl alcohol resin with an aldehyde having 4 or more carbon atoms and an aldehyde having 3 or less carbon atoms in which the total amount of the vinyl alcohol units acetalized with the aldehyde having 4 or more carbon atoms and the aldehyde having 3 or less carbon atoms is 65 to 85 mol % of all repeating units, and the molar ratio of the vinyl alcohol unit acetalized with the aldehyde having 4 or more carbon atoms to the vinyl alcohol unit acetalized with the aldehyde having 3 or less carbon atoms is from 90/10 to 0/100. Furthermore, provided are an article molded from the thermoplastic acrylic resin composition and a method of producing the thermoplastic acrylic resin composition comprising the steps of mixing a methacrylic resin (A) and a polyvinyl acetal resin (B), increasing the resin temperature to 160° C. or more, and then decreasing the resin temperature to 120° C. or less.

主权项

1. A thermoplastic acrylic resin composition, comprising:
a methacrylic resin (A) comprising 80 to 99.9% by mass of alkyl methacrylate units and 0.1 to 20% by mass of alkyl acrylate units and having a weight-average molecular weight (Mw) of 40,000 or more; and a polyvinyl acetal resin (B) comprising repeating units represented by formula (1) below:wherein R3 is an alkyl group having 2 or less carbon atoms or a hydrogen atom, R4 is an alkyl group having 3 or more carbon atoms, l is a mole fraction of vinyl alcohol units and m is a mole fraction of vinyl acetate units, k3 is a mole fraction of vinyl alcohol units acetalized by an aldehyde having 3 or less carbon atoms, and k4 is a mole fraction of vinyl alcohol units acetalized by an aldehyde having 4 or more carbon atoms, and a ratio of (k3+k4)/(k3+k4+l+m) is from 0.65 to 0.85, and a ratio of k4/k3 is from 90/10 to 1/99.