Automotive Interior Resin Composition for Heat-Humidity Stability

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Solution Overview

Problem

Conventional resins used in automotive interior materials suffer from hydrolysis and physical property deterioration in high temperature and humidity environments, leading to reduced mechanical properties and heat resistance, necessitating a material that maintains stability and appearance under such conditions.

Innovation Solution

A composite resin composition comprising specific proportions of polybutylene terephthalate resin, polyethylene terephthalate resin, (meth)acrylate compound-conjugated diene compound-aromatic vinyl compound copolymer, carboxy reactive epoxy resin, and glass fiber with SiO2, CaO, and Al2O3, which is processed through melt-kneading and extrusion to enhance heat resistance, impact stability, and crystallization rate controllability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If PC/ABS or PC/PBT resins are used in automotive interior materials, then excellent physical properties are achieved, but the resins deteriorate in high temperature and high humidity environments due to hydrolysis and transesterification

Engineering Contradiction:
Improveresin stability in high temperature and high humidity environmentVSAvoidhydrolysis and transesterification
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent introduces a specific copolymer composition containing conjugated diene compounds (10-30 parts by weight), aromatic vinyl compounds (10-30 parts by weight), and (meth)acrylate compounds (5-20 parts by weight) as an intermediary substance that prevents hydrolysis and transesterification reactions between PC and PBT resins, thereby maintaining resin stability in high temperature and high humidity environments without compromising the excellent physical properties

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent creates a composite resin composition by combining polycarbonate resin (30-70 parts by weight), polybutylene terephthalate resin (20-50 parts by weight), and the specific copolymer composition (10-60 parts by weight) in controlled ratios, achieving both excellent physical properties and resistance to hydrolysis and transesterification in harsh environments

Inventive Principle:
Principle #40Composite materials

2Strength

If conventional resin compositions are used, then manufacturing is simple, but heat resistance and impact stability are insufficient

Engineering Contradiction:
Improveimpact stability and heat resistanceVSAvoidcomposition complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The patent optimizes the compositional parameters by specifying precise weight ranges for each component: polycarbonate resin (30-70 parts), polybutylene terephthalate resin (20-50 parts), and the copolymer composition (10-60 parts), achieving enhanced impact stability and heat resistance through controlled parameter variation rather than complex formulation

Inventive Principle:
Principle #35Parameter changes

3Strength

If the resin composition is optimized for mechanical properties, then strength is improved, but fluidity and crystallization rate controllability deteriorate

Engineering Contradiction:
Improvemechanical propertiesVSAvoidfluidity and crystallization rate controllability
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The patent applies local quality by using the specific copolymer composition with conjugated diene compounds, aromatic vinyl compounds, and (meth)acrylate compounds in controlled amounts to locally modify the resin matrix, providing enhanced mechanical properties in specific regions while maintaining overall fluidity and crystallization rate controllability through the balanced formulation

Inventive Principle:
Principle #3Local quality

Data Source

PatentUS12630709B2Composite resin composition for automotive interior materials and automotive interior material including the same
Publication Date: 2026.05.19 LG CHEM LTD

AI summary

Provided is a composite resin composition for automotive interior materials and an automotive interior material including the same. The composite resin composition comprises: 47 to 52 wt % of a polybutylene terephthalate resin; 10 to 28 wt % of a (meth)acrylate compound-conjugated diene compound-aromatic vinyl compound copolymer; 8 to 14 wt % of a polyethylene terephthalate resin; 0.1 to 2.2 wt % of a carboxy reactive epoxy resin; and 10 to 28 wt % of glass fiber containing SiO2, CaO, and Al2O3, wherein an SiO2 content is greater than a sum of a CaO content and an Al2O3 content. By changing conventional components, the composite resin composition for automotive interior materials provided herein has an effect of improving heat resistance, impact stability, and crystallization rate controllability, satisfying physical property balance between mechanical properties and fluidity, and providing excellent product reliability and appearance.