Composite Molded Article Joining Polyamide and Styrene Resins

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Solution Overview

Problem

Existing methods struggle to firmly integrate fiber-reinforced resin layers with styrene-based resin layers, often resulting in poor joining strength and durability, especially when no suitable joining layer is used.

Innovation Solution

A composite molded article is created by layering a fiber-reinforced resin molded article with a polyamide-based resin as the matrix, a modified vinyl-based copolymer as the joining layer, and a styrene-based resin, where the modified vinyl-based copolymer exhibits high joining suitability to both resin types, enhancing adhesion and mechanical properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a fiber-reinforced resin layer and a styrene-based resin layer are directly joined without a joining layer, then the structure is simple, but the joining strength between layers is insufficient

Engineering Contradiction:
Improvestructure simplicityVSAvoidjoining strength
Core Design Contradiction:
Device complexityVSStrength

Solution Approach 1:

A polyamide-based resin joining layer is introduced between the fiber-reinforced resin layer and the styrene-based resin layer. This intermediate layer acts as a mediator that is compatible with both resin types, enabling effective stress transfer and achieving sufficient joining strength while maintaining structural integrity.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Strength

If a joining layer is introduced between fiber-reinforced resin and styrene-based resin, then the joining strength is improved, but the device complexity increases

Engineering Contradiction:
Improvejoining strengthVSAvoidlayer structure complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The polyamide-based resin joining layer has compositional homogeneity with the fiber-reinforced resin layer, both being polyamide-based. This homogeneity simplifies the overall structure by using compatible materials that can be processed together in a single molding step, reducing manufacturing complexity despite the additional layer.

Inventive Principle:
Principle #33Homogeneity

3Device complexity

If mechanical wrapping is used to join fiber-reinforced resin and styrene-based resin, then the structure is simple, but the integration is not firm over the entire surface

Engineering Contradiction:
Improvejoining method simplicityVSAvoidintegration reliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The mechanical wrapping method is replaced with a chemical/thermal bonding system using the polyamide-based resin joining layer. This layer bonds chemically and thermally to both the fiber-reinforced resin and styrene-based resin, providing firm integration over the entire surface area rather than relying on mechanical interlocking at discrete points.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

4Ease of manufacture

If no joining layer is used between incompatible resins, then the manufacturing process is simple, but the resins cannot be directly joined and integrated

Engineering Contradiction:
Improvemanufacturing process simplicityVSAvoidresin compatibility
Core Design Contradiction:
Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The polyamide-based resin joining layer serves multiple functions: it is compatible with both the fiber-reinforced polyamide resin and the styrene-based resin, provides structural support, enables stress transfer, and can be processed in the same molding cycle. This multi-functionality maintains manufacturing simplicity while achieving resin compatibility.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 solution achieves strong and durable integration of the resin layers with improved flexural strength and modulus, maintaining performance even under heat aging and hot water resistance tests.

Implementation Method 1

the modified vinyl-based copolymer in the molded article comprising a modified vinyl-based copolymer (B) interposed has a high joining suitability to both the polyamide-based resin in the fiber-reinforced resin molded article comprising a fiber-reinforced resin having a polyamide-based resin as a matrix resin (A) and the styrene-based resin in the molded article comprising a styrene-based resin (C)

Methodology Applied
Scientific EffectAdhesive bonding: Adhesive

Data Source

PatentUS10919271B2Composite molded article and method of manufacturing same
Publication Date: 2021.02.16 TORAY INDUSTRIES INC

AI summary

A composite molded article has (A) a fiber-reinforced resin molded article (A) including a fiber-reinforced resin having a polyamide-based resin as a matrix resin, a molded article (B) including a modified vinyl-based copolymer, and a molded article (C) including a styrene-based resin layered in this order. A layer (B) including a modified vinyl-based copolymer is interposed as a joining layer between a layer (A) of a fiber-reinforced resin having a polyamide-based resin as a matrix resin and a layer (C) including a styrene-based resin, whereby a composite molded article can be obtained in which the layers (A), (B) and (C) are strongly joined and integrated, and a composite molded article can be obtained which has excellent characteristics not realizable by a single layer of the layer (A) or the layer (C).