Methacrylic–Styrene Laminated Sheet for Ink and Laser Processing

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Solution Overview

Problem

Methacrylic-based resins exhibit poor ink adhesion and UV curable ink permeability, while styrene-based copolymers have unfavorable laser cutting processability and odor/smoke issues, and laminated sheets using these resins as rework materials suffer from reduced transparency due to refractive index differences.

Innovation Solution

A laminated sheet with a base layer of methacrylic-based resin and a surface layer of styrene-based copolymer, where the surface layer's thickness is 1-20% of the total, and styrene-based monomer units are 0.1-25% by mass, ensuring compatibility and reducing haze to 4% or less, allowing for inkjet printing and laser cutting with improved adhesion and processability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If a methacrylic-based resin is used as the base resin for resin sheets, then transparency and laser cutting processability are improved, but ink adhesion and UV curable ink permeability deteriorate

Engineering Contradiction:
ImprovetransparencyVSAvoidink adhesion
Core Design Contradiction:
Illumination intensityVSReliability

Solution Approach 1:

The patent uses a composite resin composition consisting of a methacrylic-based resin (providing transparency and laser cutting processability) and a styrene-based copolymer (providing ink adhesion and UV curable ink permeability). This composite structure allows the material to simultaneously achieve both transparency and good ink adhesion, resolving the contradiction between these two properties.

Inventive Principle:
Principle #40Composite materials

2Reliability

If a styrene-based copolymer is used to improve ink adhesion, then ink adhesion and UV curable ink permeability are improved, but laser cutting processability and odor/smoke generation deteriorate

Engineering Contradiction:
Improveink adhesionVSAvoidlaser cutting processability
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent combines a methacrylic-based resin (which provides excellent laser cutting processability and low odor/smoke generation) with a styrene-based copolymer (which provides ink adhesion). The methacrylic-based resin acts as the base material that maintains good laser cutting properties, while the styrene-based copolymer is added in controlled amounts to improve ink adhesion without significantly compromising laser cutting processability.

Inventive Principle:
Principle #40Composite materials

3Loss of substance

If a previously produced laminated sheet is used as rework material, then sustainability is improved, but transparency deteriorates due to refractive index differences

Engineering Contradiction:
ImprovesustainabilityVSAvoidtransparency
Core Design Contradiction:
Loss of substanceVSIllumination intensity

Solution Approach 1:

The patent controls the styrene content in the base layer to 1% by mass or less to suppress cloudiness and maintain transparency. By carefully adjusting this parameter, the patent achieves both sustainability (through reuse of rework materials) and transparency, resolving the contradiction between these two properties.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP4640431A1Laminated sheet, manufacturing method therefor, printed matter, and molded product
Publication Date: 2025.10.29 KURARAY CO LTD
  • EP4640431A1 patent drawingFigure 1~2
  • EP4640431A1 patent drawingFigure 3
  • EP4640431A1 patent drawingFigure 4

AI summary

The present disclosure provides a laminated sheet that has favorable ink adhesion and laser cutting processability, and is highly sustainable. The laminated sheet (1) of the present disclosure has a base layer (11) and a surface layer (21) laminated on at least one side of the base layer (11), the base layer (11) includes a methacrylic-based resin (M) including 80 to 100% by mass of methyl methacrylate units, the surface layer (21) includes a styrene-based copolymer (S), the proportion of the total thickness of the surface layer (21) to the total thickness of the laminated sheet (1) is 1 to 20%, and the haze value of a 3.0 mm-thick single-layer molded sheet of the pulverized material of the laminated sheet (1) is 4% or less.