Polyamide Resin Composition for Silicone Bleed-Free Injection Molding

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Solution Overview

Problem

Existing methods fail to effectively suppress detachment of silicone resin from molded articles and adhesion to mold surfaces during injection molding of recycled polyamide resin compositions, leading to poor mechanical properties.

Innovation Solution

A polyamide resin composition comprising polyamide resin, silicone resin, and a silane coupling agent with functional groups such as isocyanate, epoxy, or acid anhydride, along with optional ammonium salts and acid anhydrides, to chemically bond the silicone resin to the polyamide resin, preventing detachment and adhesion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If silicone resin layer is not completely separated from polyamide resin molded body during recycling, then material recycling efficiency is improved, but silicone resin detaches from molded article and adheres to mold surface causing poor quality

Engineering Contradiction:
Improvematerial recycling efficiencyVSAvoidmolded article quality
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

A silane coupling agent is introduced as an intermediary substance between the silicone resin and polyamide resin. The silane coupling agent contains both silicone resin reactive groups and polyamide resin reactive groups, creating a chemical bridge that bonds the silicone resin to the polyamide resin matrix. This mediator enables complete separation of the silicone resin layer during recycling while preventing subsequent detachment and adhesion issues in the recycled product.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The chemical composition and bonding characteristics of the interface between silicone resin and polyamide resin are changed by incorporating silane coupling agents. This parameter change transforms the interface from a weak physical bond to a strong chemical bond, enabling selective removal of silicone resin during recycling while maintaining stable bonding in the final molded article.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If silicone resin layer is completely separated from polyamide resin molded body, then molded article quality is improved, but material recycling efficiency deteriorates

Engineering Contradiction:
Improvemolded article qualityVSAvoidmaterial recycling efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The silane coupling agent serves as a mediator that enables selective and complete separation of silicone resin from polyamide resin during recycling. The dual-reactivity of the silane coupling agent allows it to remain bonded to the polyamide resin matrix while releasing the silicone resin layer, achieving complete separation without compromising recycling efficiency.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If silane coupling agent is added to bond silicone resin to polyamide resin, then silicone resin detachment and adhesion are suppressed, but manufacturing complexity increases

Engineering Contradiction:
Improvesilicone resin stabilityVSAvoidmanufacturing process complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The silane coupling agent combines multiple functions into a single substance: it bonds silicone resin to polyamide resin, enables selective separation during recycling, and prevents detachment and adhesion issues. This merging of functions into one additive simplifies the overall manufacturing process compared to using multiple separate treatments or processes.

Inventive Principle:
Principle #5Merging (Combining)

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 effectively suppresses silicone resin detachment and adhesion, maintaining excellent mechanical properties and enabling stable material recycling of polyamide resin compositions.

Implementation Method 1

a silane coupling agent (C) having at least one functional group selected from the group consisting of an isocyanate group, an epoxy group, and an acid anhydride group

Methodology Applied
Scientific EffectChemical bonding: Chemical Bonding

Data Source

PatentEP4428194B1Polyamide resin composition, molded article obtained by molding same, and methods for producing those
Publication Date: 2026.04.01 TORAY INDUSTRIES INC
  • EP4428194B1 patent drawingFigure 1

AI summary

The present invention pertains to: a polyamide resin composition obtained by compounding, with respect to 100 parts by weight of a polyamide resin (A), 0.01-12 parts by weight of a silicone resin (B) and 0.01-5 parts by weight of a silane coupling agent (C) having at least one functional group selected from the group consisting of an isocyanate group, an epoxy group, and an acid anhydride group; a molded article thereof; and methods for producing the composition and the molded article. Provided is a polyamide resin composition which, even if the polyamide resin composition contains a silicone resin as an impurity, can suppress detachment of the silicone resin from a molded article obtained through injection molding of the polyamide resin composition and ca suppress adhesion of the silicone resin to the surface of a mold during molding, and a molded article from which also can have excellent mechanical properties.