Heat resistant PMMA copolymers having high temperature and high humidity environmental stability for electronic component applications

An acrylic copolymer comprising, as polymerized monomers:

• a) from 0.2 to 20 weight percent of monomer units comprising at least one of tert-butyl cyclohexyl methacrylate;
• 3,3,5-trimethylcyclohexyl(meth)acrylate;
• tetrahydrofurfuryl methacrylate or a mixture thereof;
• b) from 80 to 99.8 weight percent (meth)acrylate monomer units;
• wherein said acrylic copolymer has:
• i) a Tg of from 116° C. to 145° C.;
• ii) a weight average molecular weight (Mw) of at least 130,000;
• and
• iii) a residual monomer level of less than 1.2 weight percent;
• wherein a composition comprising the acrylic copolymer is optically clear and passes a 1,000 hour 85° C./85% RH test for photovoltaic applications.

An acrylic copolymer comprising, as polymerized monomers:

• a) from 0.2 to 20 weight percent of monomer units comprising at least one of tert-butyl cyclohexyl methacrylate;
• 3,3,5-trimethylcyclohexyl(meth)acrylate;
• tetrahydrofurfuryl methacrylate or a mixture thereof;
• b) from 80 to 99.8 weight percent (meth)acrylate monomer units;
• wherein said acrylic copolymer has:
• i) a Tg of from 116° C. to 145° C.;
• ii) a weight average molecular weight (Mw) of at least 110,000;
• and
• iii) a residual monomer level of less than 1.2 weight percent;
• wherein a composition comprising the acrylic copolymer is optically clear and has less than 5% sagging at 1,000 hours in an 85° C./85% RH test.

An acrylic copolymer comprising, as polymerized monomers:

• a) from 0.2 to 20 weight percent of monomer units comprising at least one of tert-butyl cyclohexyl methacrylate;
• 3,3,5-trimethylcyclohexyl(meth)acrylate;
• tetrahydrofurfuryl methacrylate or a mixture thereof;
• b) from 80 to 99.8 weight percent (meth)acrylate monomer units;
• wherein said acrylic copolymer has:
• i) a Tg of from 116° C. to 145° C.;
• ii) a weight average molecular weight (Mw) of at least 110,000;
• and
• iii) a residual monomer level of less than 1.2 weight percent;
• wherein a composition comprising the acrylic copolymer is optically clear and, in the form of a sheet or film, has minimal crazing visually after 1,000 hours in an 85° C./85% RH test for photovoltaic applications.

An acrylic copolymer comprising, as polymerized monomers:

• a) from 0.2 to 20 weight percent of monomer units comprising at least one of tert-butyl cyclohexyl methacrylate;
• 3,3,5-trimethylcyclohexyl(meth)acrylate;
• tetrahydrofurfuryl methacrylate or a mixture thereof;
• b) from 80 to 99.8 weight percent (meth)acrylate monomer units;
• wherein said acrylic copolymer has:
• i) a Tg of from 116° C. to 145° C.;
• ii) a weight average molecular weight (Mw) of at least 110,000;
• and
• iii) a residual monomer level of less than 1.2 weight percent;
• wherein a composition comprising the acrylic copolymer is optically clear and 3.2 mm thick samples of the composition have no visible stress crazing defects and sagging of less than 4% after 600 hours of exposure of −40° C. to 85° C./85% RH.