Multilayer Body Adhesion via Isosorbide Polycarbonate Ratio
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Solution Overview
Problem
Current multilayer bodies composed of isosorbide polycarbonates and other thermoplastic resins face challenges with adhesion, chemical resistance, and surface hardness, particularly when used in applications where human contact is involved, such as with sunscreen agents or perfumes, and have limitations in achieving a balance of transparency, chemical resistance, and adhesion.
Innovation Solution
A multilayer body is created using a resin composition that includes a polycarbonate resin with isosorbide and a monomer having a specific spiro ring structure, combined with an acrylic resin in a specific weight ratio, which enhances adhesion to other thermoplastic resins while maintaining excellent transparency, chemical resistance, and surface hardness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If isosorbide polycarbonate is used to achieve excellent heat resistance, impact resistance, and weathering resistance, then these properties are improved, but adhesion to other resins (such as PC-A or PMMA) becomes markedly poor
Solution Approach 1:
The patent applies parameter changes by precisely controlling the copolymerization ratio of isosorbide in the polycarbonate resin. By setting the isosorbide content within a specific range (0.1-10 mol%), the invention optimizes the balance between adhesion and other properties. This parameter adjustment allows the resin to achieve sufficient adhesion to PC-A and PMMA while maintaining the excellent heat resistance, impact resistance, and weathering resistance inherent to isosorbide polycarbonates.
2Strength
If the copolymerization ratio of isosorbide is reduced to achieve adhesion to PC-A, then adhesion is improved, but chemical resistance becomes poor
Solution Approach 1:
The patent resolves this contradiction by establishing an optimal parameter range for isosorbide copolymerization ratio (0.1-10 mol%). Within this range, the resin maintains both adhesion to PC-A and chemical resistance. The lower bound (0.1 mol%) ensures sufficient adhesion, while the upper bound (10 mol%) preserves chemical resistance by maintaining enough isosorbide content.
3Strength
If methacrylate resin is used to achieve high transparency and high surface hardness, then these properties are improved, but resistance to chemicals used in daily life (such as sunscreen agents) becomes poor
Solution Approach 1:
The patent applies composite materials by creating a multilayer body that combines polycarbonate resin (with isosorbide) and acrylic resin. The polycarbonate layer provides excellent chemical resistance, heat resistance, and weathering resistance, while the acrylic resin layer can provide high transparency and surface hardness. This composite structure allows both sets of properties to coexist without compromising either.
Data Source
AI summary
A multilayer body includes at least one layer (C) including a resin composition; and at least one layer (D) including a thermoplastic resin, in which the resin composition includes a polycarbonate resin (A) and an acrylic resin (B) in a weight ratio of 40:60 to 99:1, the polycarbonate resin (A) includes, as main repeating units, a unit (a-1) represented by the following formula (a-1):and a unit (a-2) represented by the following formula (a-2):wherein W represents an alkylene group having 1 to 20 carbon atoms or a cycloalkylene group having 6 to 20 carbon atoms, R represents a branched or linear alkyl group having 1 to 20 carbon atoms, or a cycloalkyl group having 6 to 20 carbon atoms and optionally having a substituent, and m represents an integer of 0 to 10, and the molar ratio of the unit (a-1) and the unit (a-2) (a-1/a-2) is 40/60 to 95/5. The multilayer body has excellent transparency, chemical resistance, surface hardness, and adhesion.