Methacrylic resin composition for non-contact hot plate welding, molded article, and method for producing same

Abstract

The present invention provides a methacrylic resin composition for non-contact hot plate welding comprising a methacrylic resin comprising 80 to 99.9% by mass of a methacrylic acid ester monomer unit and 0.1 to 20% by mass of a unit of at least one additional vinyl monomer copolymerizable with the methacrylic acid ester monomer, wherein the methacrylic resin composition has a melt flow rate (MFR) of 2.5 g/10 min or lower at 230° C. at a load of 3.8 kg.

1 . A methacrylic resin composition for non-contact hot plate welding comprising a methacrylic resin comprising 80 to 99.9% by mass of a methacrylic acid ester monomer unit and 0.1 to 20% by mass of a unit of at least one additional vinyl monomer copolymerizable with the methacrylic acid ester monomer, wherein
 the methacrylic resin composition has a melt flow rate (MFR) of 2.5 g/10 min or lower at 230° C. at a load of 3.8 kg.   
     
     
         2 . The methacrylic resin composition for non-contact hot plate welding according to  claim 1 , wherein the methacrylic resin is a methacrylic resin which
 has a weight-average molecular weight of 300000 or lower as measured by gel permeation chromatography (GPC), and   contains 6 to 50% of a component having a molecular weight that is 5 times or more lower than a peak top molecular weight (Mp) obtained from a GPC elution curve.   
     
     
         3 . The methacrylic resin composition for non-contact hot plate welding according to  claim 1 , wherein the methacrylic resin is a methacrylic resin in which
 an abundance of a component having a molecular weight of 250000 or higher obtained from a GPC elution curve is 12% or more of a GPC area.   
     
     
         4 . The methacrylic resin composition for non-contact hot plate welding according to  claim 1 , wherein the methacrylic resin
 has an extrapolated onset temperature (° C.) of 120° C. or lower as determined from a glass transition curve obtained by heating from 40° C. to 210° C. at a heating rate of 10° C./min according to JIS-K-7121 with α-alumina as a reference in a nitrogen gas atmosphere using a differential scanning calorimeter (DSC).   
     
     
         5 - 6 . (canceled) 
     
     
         7 . A molded article comprising a molded article (A) welded with an additional molded article (B),
 the molded article (A) comprising a methacrylic resin comprising 80 to 99.9% by mass of a methacrylic acid ester monomer unit and 0.1 to 20% by mass of a unit of at least one additional vinyl monomer copolymerizable with the methacrylic acid ester monomer, wherein   the molded article (A) has a melt flow rate (MFR) of 2.5 g/10 min or lower at 230° C. at a load of 3.8 kg.   
     
     
         8 . The molded article according to  claim 7 , wherein the methacrylic resin is a methacrylic resin which
 has a weight-average molecular weight of 300000 or lower as measured by gel permeation chromatography (GPC), and   contains 6 to 50% of a component having a molecular weight that is 5 times or more lower than a peak top molecular weight (Mp) obtained from a GPC elution curve.   
     
     
         9 . The molded article according to  claim 7 , wherein the methacrylic resin is a methacrylic resin in which
 an abundance of a component having a molecular weight of 250000 or higher obtained from a GPC elution curve is 12% or more of a GPC area.   
     
     
         10 . The molded article according to  claim 7 , wherein the methacrylic resin
 has an extrapolated onset temperature (° C.) of 120° C. or lower as determined from a glass transition curve obtained by heating from 40° C. to 210° C. at a heating rate of 10° C./min according to JIS-K-7121 with α-alumina as a reference in a nitrogen gas atmosphere using a differential scanning calorimeter (DSC).   
     
     
         11 . The molded article according to  claim 7 , wherein the molded article (A) has a water absorption rate of 0.5% by mass or lower. 
     
     
         12 - 13 . (canceled) 
     
     
         14 . The molded article according to  claim 7 , wherein the molded article (B) is a molded article of an ABS-based resin. 
     
     
         15 . A member for a vehicle, comprising the molded article according to  claim 7 . 
     
     
         16 . The member for the vehicle according to  claim 15 , wherein the member for the vehicle is at least one member selected from the group consisting of a taillight cover, a headlight cover, and a meter panel. 
     
     
         17 . A method for producing a molded article, comprising the steps of:
 heating a molded article (A) in no contact with a hot plate so that a surface of the molded article (A) is melted, the molded article (A) comprising a methacrylic resin comprising 80 to 99.9% by mass of a methacrylic acid ester monomer unit and 0.1 to 20% by mass of a unit of at least one additional vinyl monomer copolymerizable with the methacrylic acid ester monomer, wherein the molded article (A) has a melt flow rate (MFR) of 2.5 g/10 min or lower at 230° C. at a load of 3.8 kg; and   welding the molded article (A) with an additional molded article (B).   
     
     
         18 . The method for producing the molded article according to  claim 17 , wherein the methacrylic resin is a methacrylic resin which has a weight-average molecular weight of 300000 or lower as measured by gel permeation chromatography (GPC), and which contains 6 to 50% of a component having a molecular weight that is 5 times or more lower than a peak top molecular weight (Mp) obtained from a GPC elution curve. 
     
     
         19 . The method for producing the molded article according to  claim 17 , wherein the methacrylic resin is a methacrylic resin in which
 an abundance of a component having a molecular weight of 250000 or higher obtained from a GPC elution curve is 12% or more of a GPC area.   
     
     
         20 . The method for producing the molded article according to  claim 17 , wherein the methacrylic resin
 has an extrapolated onset temperature (° C.) of 120° C. or lower as determined from a glass transition curve obtained by heating from 40° C. to 210° C. at a heating rate of 10° C./min according to JIS-K-7121 with α-alumina as a reference in a nitrogen gas atmosphere using a differential scanning calorimeter (DSC).   
     
     
         21 . The method for producing the molded article according to  claim 17 , wherein the molded article (A) has a water absorption rate of 0.5% by mass or lower. 
     
     
         22 . The method for producing the molded article according to  claim 17 , wherein the molded article (B) is a molded article of an ABS-based resin.