Laminate

Abstract

To provide a laminate which uses a bio-polycarbonate resin in a surface layer, has excellent moldability, and easily maintains unevenness (embossment) formed on the surface of the surface layer even if vacuum molding is performed.SOLUTION: A laminate has a surface layer 1 and a core layer 2, wherein the surface layer 1 contains a polycarbonate-based resin having a structural unit derived from isosorbide, and the core layer 2 contains a polycarbonate resin and a copolyester resin.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a laminate having a core layer and a surface layer. [Background technology]

[0002] In recent years, for example, polycarbonate resins, which have excellent impact resistance, heat insulation properties, etc., have come to be used in interior and exterior components of automobiles in order to reduce the weight of automobiles and improve their design.

[0003] On the other hand, bio-polycarbonate resins, which are made primarily from plant-derived isosorbide, have been proposed as polycarbonate resins that contribute to the realization of a carbon-free society and have been put to practical use (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-196158 Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention aims to provide a laminate that uses a bio-polycarbonate resin for the surface layer, has good formability, and easily maintains the unevenness (embossment, etc.) formed on the surface of the surface layer even when vacuum forming is performed. [Means for solving the problem]

[0006] In order to achieve the above object, the laminate of the present invention is a laminate having a surface layer and a core layer, characterized in that the surface layer contains a polycarbonate-based resin having structural units derived from isosorbide, and the core layer contains a polycarbonate resin and a copolyester resin.

[0007] In this case, the weight ratio of the polycarbonate resin and the copolyester resin in the core layer may be polycarbonate:copolyester=20:80 to 80:20.

[0008] The core layer may have a Vicat softening temperature of 85 to 135°C.

[0009] Furthermore, the polycarbonate resin having structural units derived from isosorbide contained in the surface layer may contain more than 50 mol % of structural units derived from isosorbide and less than 50 mol % of structural units derived from 1,4-cyclohexanedimethanol.

[0010] The surface layer may have a storage modulus at 190° C. of 0.4 Pa or more.

[0011] Furthermore, the surface of the surface layer may be formed with irregularities. [Effects of the Invention]

[0012] The laminate of the present invention contains a surface layer of a polycarbonate resin having structural units derived from plant-derived isosorbide, and a core layer of a polycarbonate resin and a copolyester resin. Since it contains the compound, it has good formability and the unevenness (embossment, etc.) formed on the surface of the surface layer is easily maintained even when vacuum forming is performed. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a diagram showing a laminate structure of an embodiment of a laminate of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, an embodiment of the laminate of the present invention will be described.

[0015] FIG. 1 shows a laminate structure diagram of one embodiment of the laminate of the present invention. This laminate has a surface layer 1 and a core layer 2, where the surface layer 1 contains a polycarbonate resin having structural units derived from plant-derived isosorbide, and the core layer 2 contains a polycarbonate resin and a copolyester resin.

[0016] An example of a polycarbonate resin having structural units derived from isosorbide that constitutes the surface layer 1 is the "Durabio (registered trademark)" series of bio-engineering plastics manufactured by Mitsubishi Chemical Corporation, which uses plant-derived isosorbide as the main raw material. This bio-polycarbonate resin has high transparency, excellent optical properties, and excellent scratch resistance. It also has impact resistance comparable to that of general-purpose polycarbonate resin made from bisphenol A, and exhibits higher chemical resistance than general-purpose polycarbonate resin.

[0017] The polycarbonate resin having structural units derived from isosorbide contained in the surface layer 1 preferably contains more than 50 mol% of structural units derived from isosorbide and less than 50 mol% of structural units derived from 1,4-cyclohexanedimethanol. From the viewpoint of suppressing changes in gloss before and after vacuum processing, the polycarbonate resin more preferably contains more than 55 mol% of structural units derived from isosorbide and less than 45 mol% of structural units derived from 1,4-cyclohexanedimethanol, and even more preferably contains more than 60 mol% of structural units derived from isosorbide and less than 40 mol% of structural units derived from 1,4-cyclohexanedimethanol.

[0018] The storage modulus of the surface layer 1 at 190°C is 0.4 Pa or more, preferably 0.5 Pa or more, and more preferably 0.6 Pa or more. If the storage modulus of the surface layer 1 at 190°C is less than 0.4 Pa, the change in glossiness before and after vacuum forming is large, and the desired texture may not be obtained.

[0019] The difference in 60° gloss value before and after vacuum forming of the surface of the surface layer 1 is preferably 9% or less, more preferably 8% or less, and even more preferably 7% or less. If the difference in 60° gloss value exceeds 8%, the gloss state before and after vacuum forming will change significantly, and the desired texture may not be obtained.

[0020] The thickness of the surface layer 1 is preferably 30 to 200 μm, more preferably 50 to 100 μm, for reasons of performance, cost, productivity, etc.

[0021] The surface of the surface layer 1 may be smooth and flat, or may have irregularities formed thereon. Methods for forming irregularities on the surface include, for example, press processing (embossing, texturing), laser processing, end mill processing, and lithography. Alternatively, a mold having an irregular surface structure may be produced by molding with a metal 3D printer. Examples of embossing include a method using an embossing mold roll and a method using an embossing press plate.

[0022] The polycarbonate resin contained in the core layer 2 is not particularly limited, and is preferably a general-purpose polycarbonate resin with excellent impact resistance. The copolyester resin of the core layer 2 is not particularly limited, and examples thereof include the copolyester "ECOZEN (registered trademark)" series manufactured by SK CHEMICALS and the "Tritan (registered trademark)" series manufactured by Eastman Chemical.

[0023] The weight ratio of polycarbonate resin to copolyester resin in the core layer 2 is preferably polycarbonate:copolyester=20:80 to 80:20, more preferably polycarbonate:copolyester=30:70 to 70:30, in order to suppress changes in glossiness before and after vacuum processing.

[0024] The Vicat softening temperature of the core layer 2 is preferably 85 to 135° C., more preferably 88 to 133° C., and even more preferably 90 to 130° C. If the Vicat softening temperature is less than 85° C., the heat resistance during use may be insufficient, while if it exceeds 135° C., the vacuum forming time may become longer, and the change in gloss of the surface of the surface layer 1 before and after vacuum processing may become greater.

[0025] Specifically, this laminate can be formed using the following materials and forming method.

[0026] [material] Surface layer 1 (thickness 50-100 μm) Bio PC1: "Durabio (registered trademark) D5380R" (Mitsubishi Chemical Corporation) Polycarbonate resin with structural units derived from isosorbide (ISB / CHDM=50 / 50) It has higher pencil hardness and better chemical resistance than general polycarbonate resin. Melt Volume Rate (MVR): 4cm 3 / 10min, deflection temperature under load: 82℃ Bio PC2: "Durabio (registered trademark) D7340IR" (Mitsubishi Chemical Corporation) Polycarbonate resin with structural units derived from isosorbide (ISB / CHDM=70 / 30) It has higher pencil hardness and better chemical resistance than general polycarbonate resin. Melt Volume Rate (MVR): 8cm 3 / 10min, deflection temperature under load: 102℃ ○ Core layer 2 (thickness 1.35~1.65mm) PC: "Caliber (product name) 300-8" (manufactured by Sumika Polycarbonate Co., Ltd.) Made of general polycarbonate resin, it has excellent impact resistance. Glass transition temperature Tg: 157℃ Copolyester: "ECOZEN (registered trademark) HF502" (SK CHEMICALS) Glass transition temperature Tg: 95℃

[0027] [Molding method (molding conditions)] Co-extrusion molding The material for surface layer 1 (bio-PC) and the material for core layer 2 (PC and copolyester) are melted and kneaded in an extruder, and the two layers of resin extruded from the die are glossed with a polishing roll at a temperature of 100-180°C to form a sheet. After forming, the sheet is heat-pressed at a surface temperature of 170°C using a press plate with an embossed pattern to emboss the surface. Here, the material for the surface layer 1 (bio-PC) is extruded through a die at 200 to 250°C, and the material for the core layer 2 (PC and copolyester) is extruded at 240 to 280°C. ○Vacuum forming The sheet is heated at 200-300°C, and a two-stage Bo Vacuum forming is performed by pressing an x-shaped mold against the material.

[0028] [Evaluation method] Vicat softening temperature The Vicat softening temperature was measured in accordance with JIS-K7206:2016 using the following equipment. Measurement equipment: Heat distortion tester / deflection temperature tester "148-HD-3" (Yasuda Seiki Seisakusho) Storage modulus The storage modulus was measured under the following conditions in accordance with JIS-K7244-4. Measurement temperature: 190℃ Measuring equipment: Dynamic viscoelasticity measuring device "DMA-Q800" (TA Instruments) Gloss (gloss meter) The 60° gloss of the surface of the surface layer was measured in accordance with JIS-Z8741:1997. Measuring equipment: Gloss checker "IG-320" (manufactured by Horiba Ltd.) Gloss (visual) The gloss state of the surface of the laminate (surface of the surface layer) before and after vacuum forming is visually checked under fluorescent light. ◯: There is no significant difference in gloss before and after vacuum application. ×: There is a large difference in gloss before and after vacuum application, and there is a glossy appearance. ○Workability The state of the sheet after vacuum forming was visually inspected and evaluated according to the following criteria. 〇: Can be molded exactly as the mold suggests. ×: Unable to mold according to the mold. ○Length change rate Using a microscope (manufactured by Keyence Corporation), the change in length of the long side of the rectangular shape before and after vacuum forming is confirmed. ○Molding time (vacuum forming) The molding time was the time from the start of heating the sample to the time of drawdown.

[0029] Examples and comparative examples of this laminate are shown in Table 1.

[0030] [Table 1]

[0031] From Table 1, the following points were confirmed: The laminates of Examples 1 to 3 (material of core layer 2: PC and copolyester) can be formed with a short forming time (heating time) during vacuum forming, so even if they are formed (vacuum formed) to a predetermined product shape after sheet forming (co-extrusion molding), the shape of the irregularities (embossments) 11 formed on the surface of the surface layer 1 during sheet forming (co-extrusion molding) is easily maintained. Regarding the differences due to the copolyester blend ratio, when the blend ratio is 50%, the glossiness (gloss value) of the surface layer can be maintained at a low value even when vacuum molding is performed. Whether the blend ratio is greater or less than 50%, the glossiness (gloss value) becomes high. As the blend ratio increases above 50%, the molding time (heating time) can be shortened, but the effect of the heating temperature becomes greater, and it is thought that the stretching of the surface shape increases. The laminates of Examples 1 to 3 (surface layer 1 material (bio-PC): structural units derived from isosorbide are greater than 50 mol % and structural units derived from 1,4-cyclohexanedimethanol are less than 50 mol %) use a bio-polycarbonate resin for the surface layer, have good formability, and have a storage modulus of the surface layer at 190°C of 0.4 Pa or more (preferably 0.5 Pa or more, more preferably 0.6 Pa or more), and are likely to maintain the shape of the irregularities (embossments) 11 formed on the surface of the surface layer 1 during sheet molding (co-extrusion molding) even when molded (vacuum molded) to a predetermined product shape after sheet molding (co-extrusion molding).

[0032] The laminate of the present invention has been described above based on its embodiment, but the present invention is not limited to the above configuration, and the configuration can be changed as appropriate within the scope of the spirit of the present invention. [Industrial Applicability]

[0033] The laminate of the present invention uses a bio-polycarbonate resin for the surface layer, has good formability, and is easy to maintain the unevenness (embossing, etc.) formed on the surface of the surface layer even when vacuum-molded. Therefore, it can be suitably used, for example, in laminates used in interior and exterior components of automobiles for the purpose of reducing the weight of automobiles and improving their design. [Explanation of symbols]

[0034] 1 Surface layer 11 Embossing 2 Core layer

Claims

1. A laminate having a surface layer and a core layer, The surface layer is It contains a polycarbonate resin having a structural unit derived from isosorbide, The core layer comprises a polycarbonate resin and a copolyester resin. A laminate characterized by:

2. The weight ratio of the polycarbonate resin and the copolyester resin in the core layer is polycarbonate:copolyester=20:80 to 80:

20. The laminate according to claim 1 .

3. The Vicat softening temperature of the core layer is 85 to 135°C.

3. The laminate according to claim 1 or 2.

4. The polycarbonate resin having a structural unit derived from isosorbide contained in the surface layer is The structural unit derived from isosorbide is greater than 50 mol %, The structural unit derived from 1,4-cyclohexanedimethanol is less than 50 mol % 3. The laminate according to claim 1 or 2.

5. The storage modulus of the surface layer at 190°C is 0.4 Pa or more.

3. The laminate according to claim 1 or 2.

6. The surface of the surface layer is formed with irregularities.

3. The laminate according to claim 1 or 2.

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