Polypropylene Resin for Low-Temperature Injection Molding

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Solution Overview

Problem

Current methods for integrating skin fabric into vehicle interior parts through injection molding face challenges such as degradation of soft skin fabric due to high temperatures, leading to surface quality issues and increased costs, particularly with polypropylene complex resins requiring high injection molding temperatures.

Innovation Solution

A polypropylene complex resin composition comprising a high-crystalline ethylene-propylene copolymer, ultrahigh fluidity homopolypropylene, olefin-based elastomer, inorganic reinforcing agent, and additives, allowing for injection molding at lower temperatures (180°C to 200°C) to maintain the softness and integrity of the skin fabric.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If high injection molding temperature (215°C to 235°C) is used for polypropylene complex resin, then moldability is improved, but skin fabric degrades causing surface quality deterioration

Engineering Contradiction:
ImprovemoldabilityVSAvoidskin fabric degradation
Core Design Contradiction:
Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The patent changes the temperature parameter from conventional high temperature (215-235°C) to low temperature (170-200°C) injection molding. This is achieved by modifying the polypropylene complex resin composition to include specific components (polypropylene resin, olefin-based elastomer, inorganic reinforcing agent, and additive) that enable low-temperature processing while maintaining moldability and preventing skin fabric degradation.

Inventive Principle:
Principle #35Parameter changes

2Strength

If conventional polypropylene complex resin is used, then structural strength is achieved, but injection molding temperature must be high causing process complexity

Engineering Contradiction:
Improvestructural strengthVSAvoidprocess complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The patent uses a composite resin composition consisting of polypropylene resin as the base, olefin-based elastomer for flexibility and low-temperature processability, inorganic reinforcing agent for structural strength, and additive for overall performance enhancement. This composite structure achieves both strength requirements and simplified low-temperature processing in one material system.

Inventive Principle:
Principle #40Composite materials

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

Enables the production of high-quality, cost-effective, and simplified integral molded articles with improved moldability and appearance, reducing defects and VOC emissions while maintaining the softness of the skin fabric.

Implementation Method 1

a polypropylene complex resin composition capable of being injection-molded under low temperature conditions of about 180°C to about 200°C

Methodology Applied
Scientific EffectMelting: Melting

Data Source

PatentEP3403884B1Polypropylene complex resin composition for low-temperature injection molding
Publication Date: 2019.09.25 HYUNDAI MOTOR CO LTD
  • EP3403884B1 patent drawingFigure 1

AI summary

A polypropylene complex resin composition for low-temperature injection molding, may include (A) a polypropylene resin; (B) an olefin-based elastomer; (C) an inorganic reinforcing agent; and (D) an additive, wherein (A) the polypropylene resin is a polypropylene mixed resin including: about 100 parts by weight of (A-1) a high-crystalline ethylene-propylene copolymer having an isotactic index of about 98 to 100% and a melt flow index value of about 20 to 50 g/10 min (2.16 kg, 230°C); and about 5 to 20 parts by weight of (A-2) an ultrahigh fluidity homopolypropylene having a melt flow index value of about 1,000 to 1,800 g/10 min (2.16 kg, 230°C).