Patent ID: 8603633
Filing Date: 2013-12-10
Classification: B23K,B32B,B41M,B42D,Y10T

Abstract:
1. A laser marking multilayer sheet comprising a multilayer sheet A, and a multilayer sheet B that is stacked on the multilayer sheet A, the multilayer sheet A being a transparent laser marking multilayer sheet that includes a skin layer and a core layer, and includes at least three layers stacked by a coextrusion method, the skin layer that forms each outermost layer of the multilayer sheet A being formed of a noncrystalline aromatic polyester resin composition that includes based on 100 parts by mass of a copolyester resin, 0.01 to 3 parts by mass of at least one lubricant selected from a fatty acid ester, a fatty acid amide, and a fatty acid metal salt, the copolyester resin including dicarboxylic acid units mainly including terephthalic acid units, ethylene glycol units (I), and glycol units mainly including 1,4-cyclohexanedimethanol units (II), the ratio ((I)/(II)) of the ethylene glycol units (I) to the 1,4-cyclohexanedimethanol units (II) being 90 to 30/10 to 70 mol %, the core layer of the multilayer sheet A being formed of a polycarbonate resin composition that includes based on 100 parts by mass of a polycarbonate resin, 0.0001 to 3 parts by mass of carbon black that is an energy absorber, or a mixture of 0.0001 to 3 parts by mass of carbon black and 0 to 6 parts by mass of at least one compound selected from a metal oxide, a metal sulfide, a metal carbonate, and a metal silicate having an average particle size of less than 150 nm, the multilayer sheet A having a thickness of 50 to 150 μm, and the thickness of the core layer accounting for 35% or more and less than 85% of the total thickness of the multilayer sheet A, the multilayer sheet B being a colored laser marking multilayer sheet that includes a skin layer and a core layer, and includes at least three layers stacked by a coextrusion method, the skin layer that forms each outermost layer of the multilayer sheet B being formed of a noncrystalline aromatic polyester resin composition that includes based on 100 parts by mass of a copolyester resin, 0 to 3 parts by mass of at least one lubricant selected from a fatty acid ester, a fatty acid amide, and a fatty acid metal salt, the copolyester resin including dicarboxylic acid units mainly including terephthalic acid units, ethylene glycol units (I), and glycol units mainly including 1,4-cyclohexanedimethanol units (II), the ratio ((I)/(II)) of the ethylene glycol units (I) to the 1,4-cyclohexanedimethanol units (II) being 90 to 30/10 to 70 mol %, the core layer of the multilayer sheet B being formed of a polycarbonate resin composition that includes based on 100 parts by mass of a polycarbonate resin, 0.0001 to 3 parts by mass of carbon black that is an energy absorber, or a mixture of 0.0001 to 3 parts by mass of carbon black and 0 to 6 parts by mass of at least one compound selected from a metal oxide, a metal sulfide, a metal carbonate, and a metal silicate, and 1 part by mass or more of an inorganic pigment, the multilayer sheet B having a thickness of 50 to 250 μm, and the total thickness of the core layer accounting for 35% or more and less than 85% of the thickness of the multilayer sheet B.