Transparent Resin Laminate With Adhesive-Free Impact Bonding

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Solution Overview

Problem

Existing transparent molded articles, such as sunroofs, face challenges with low lightness, light resistance, and impact resistance due to the limitations of materials like glass, polycarbonate, and polymethylmethacrylate, and existing layered structures suffer from insufficient contact and impact resistance.

Innovation Solution

A laminate composed of a first layer of alicyclic polyamide resin with 20 mmol/kg or greater amino groups and a second layer of acid-modified (meth)acrylic resin with 100 mmol/kg or greater carboxyl groups, integrated without an adhesive layer, enhancing transparency, lightness, and impact resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Duration of action of stationary object

If glass is used for transparent molded articles, then light resistance is improved, but lightness and impact resistance deteriorate

Engineering Contradiction:
Improvelight resistanceVSAvoidimpact resistance
Core Design Contradiction:
Duration of action of stationary objectVSStrength

Solution Approach 1:

The patent uses a composite structure consisting of a PMMA resin layer and a polyamide resin layer. The PMMA layer provides light resistance and transparency, while the polyamide layer provides impact resistance. This composite material approach allows the molded article to simultaneously achieve good light resistance and high impact resistance, resolving the contradiction between these two properties.

Inventive Principle:
Principle #40Composite materials

2Strength

If polycarbonate is used for transparent molded articles, then impact resistance is improved, but light resistance deteriorates

Engineering Contradiction:
Improveimpact resistanceVSAvoidlight resistance
Core Design Contradiction:
StrengthVSDuration of action of stationary object

Solution Approach 1:

The patent employs a composite structure where the PMMA resin layer provides excellent light resistance and transparency, while the polyamide resin layer provides high impact resistance. By combining these two materials with different property profiles, the invention achieves both high impact resistance and superior light resistance, resolving the contradiction present in single-material solutions like polycarbonate.

Inventive Principle:
Principle #40Composite materials

3Weight of moving object

If polymethylmethacrylate is used for transparent molded articles, then lightness is improved, but impact resistance deteriorates

Engineering Contradiction:
ImprovelightnessVSAvoidimpact resistance
Core Design Contradiction:
Weight of moving objectVSStrength

Solution Approach 1:

The patent uses a composite structure where the PMMA resin layer maintains the lightness and transparency advantages, while the polyamide resin layer compensates for the low impact resistance. This composite approach allows the molded article to remain lightweight while achieving high impact resistance, resolving the contradiction between lightness and impact resistance.

Inventive Principle:
Principle #40Composite materials

4Strength

If multiple resin layers are layered to improve physical properties, then impact resistance and light resistance are improved, but steady contact between layers deteriorates

Engineering Contradiction:
Improveimpact resistanceVSAvoidsteady contact between layers
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent specifies precise parameter ranges for the resin compositions, including the type of polyamide resin (with specific amino group content), the type of PMMA resin, and the thickness ratios of the layers. By controlling these parameters, the invention achieves both high impact resistance and excellent steady contact between layers, resolving the contradiction between mechanical strength and interlayer bonding reliability.

Inventive Principle:
Principle #35Parameter changes

5Reliability

If adhesive layers are used to bond resin layers, then steady contact between layers is improved, but transparency and light resistance deteriorate

Engineering Contradiction:
Improvesteady contact between layersVSAvoidlight resistance
Core Design Contradiction:
ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The patent employs a self-bonding mechanism where the polyamide resin layer and PMMA resin layer are directly bonded to each other through molecular-level adhesion without requiring an intermediate adhesive layer. The functional groups on the polyamide resin (amino groups) and the PMMA resin (ester groups) form strong intermolecular bonds, achieving both excellent steady contact and maintaining high transparency and light resistance, thus resolving the contradiction between bonding reliability and optical performance.

Inventive Principle:
Principle #25Self-service

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The laminate achieves improved mechanical properties, including higher impact resistance and rigidity, with the second layer providing strength and compatibility for a hard coat layer, suitable for applications like automobile sunroofs.

Implementation Method 1

a first layer formed of a first resin composition containing an alicyclic polyamide resin having 20 mmol/kg or greater of amino groups, and a second layer formed of a second resin composition containing an acid-modified (meth)acrylic resin are in contact with each other and integrated

Methodology Applied
Scientific EffectChemical bonding: Chemical Bonding

Data Source

PatentUS12472667B2Laminate, method for producing same, and use of same
Publication Date: 2025.11.18 POLYPLASTICS-EVONIK CORP

AI summary

Prepared is a laminate including: a first layer formed of a first resin composition containing a first resin; and a second layer formed of a second resin composition containing a second resin, the first layer and the second layer being in contact with each other and integrated. The first resin includes an alicyclic polyamide resin having 20 mmol/kg or greater of amino groups, and the second resin includes an acid-modified (meth)acrylic resin. The second resin may have 100 mmol/kg or greater of carboxyl groups. The acid-modified (meth)acrylic resin may be an acid-modified polymethylmethacrylate resin. An average thickness of the first layer may be 0.15 times or more of an average thickness of the second layer. The average thickness of the first layer may be 200 μm or greater. When a weight is dropped onto the second layer side, the laminate may have a DuPont impact strength of 500 N/inch or greater. The laminate has excellent transparency, lightness, light resistance, and impact resistance.