Thermoplastic Polymer Composition for Scratch Resistance and Transparency

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Solution Overview

Problem

Current thermoplastic polymer compositions used in molded products, such as sheets or films, face challenges with transparency, ease of coating, and mechanical properties, particularly in applications where frequent friction and aesthetic appearance are critical, while also requiring improved scratch resistance and abrasion resistance.

Innovation Solution

A thermoplastic polymer composition comprising a block copolymer with α-methylstyrene and conjugated diene or isobutylene units, an acryl-based polymer, and a softening agent, formulated to achieve a sea-island structure with specific particle size distribution and molecular weight ranges, enhancing transparency, coating ease, and mechanical properties while maintaining scratch and abrasion resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If conventional thermoplastic polymer compositions are used to improve flexibility and rubber elasticity, then the material becomes softer and more elastic, but scratch resistance and abrasion resistance deteriorate

Engineering Contradiction:
Improveflexibility and rubber elasticityVSAvoidscratch resistance and abrasion resistance
Core Design Contradiction:
Adaptability or versatilityVSStrength

Solution Approach 1:

The patent uses a composite material system consisting of a styrene-based thermoplastic elastomer (matrix) combined with a methacryl-based resin (dispersed phase). This composite structure allows the matrix to provide flexibility and rubber elasticity while the dispersed methacryl-based resin particles provide scratch resistance and abrasion resistance, resolving the contradiction between softness and surface hardness.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent creates local quality differentiation by having the methacryl-based resin distributed as discrete particles within the styrene-based thermoplastic elastomer matrix. The continuous matrix phase provides flexibility and elasticity throughout the material, while the dispersed resin particles provide localized surface hardness and scratch resistance where they are distributed, allowing different regions to fulfill different functional requirements.

Inventive Principle:
Principle #3Local quality

2Illumination intensity

If acryl-based resin is added to retain surface characteristics and weather resistance, then transparency and surface hardness are improved, but mold processability and flexibility may deteriorate

Engineering Contradiction:
Improvetransparency and surface characteristicsVSAvoidmold processability
Core Design Contradiction:
Illumination intensityVSEase of manufacture

Solution Approach 1:

The patent optimizes the composition parameters by carefully controlling the types and amounts of styrene-based thermoplastic elastomer and methacryl-based resin used. By adjusting these compositional parameters within specific ranges, the patent achieves a balance where the methacryl-based resin provides transparency and surface characteristics while the styrene-based matrix maintains adequate mold processability and flexibility.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses localized dispersion of methacryl-based resin particles within the styrene-based thermoplastic elastomer matrix. This allows the resin to provide transparency and surface characteristics in the dispersed phase while the continuous matrix phase maintains the bulk material's processability and flexibility, preventing overall deterioration of manufacturing properties.

Inventive Principle:
Principle #3Local quality

3Adaptability or versatility

If hydrogenated block copolymer is used to improve flexibility and low-temperature characteristics, then the material becomes more flexible and weather-resistant, but scratch resistance becomes insufficient

Engineering Contradiction:
Improveflexibility and low-temperature characteristicsVSAvoidscratch resistance
Core Design Contradiction:
Adaptability or versatilityVSStrength

Solution Approach 1:

The patent combines hydrogenated block copolymer (providing flexibility and low-temperature characteristics) with methacryl-based resin (providing scratch resistance). The composite structure allows the hydrogenated block copolymer matrix to deliver elastic properties and cold flexibility while the dispersed methacryl-based resin particles provide the necessary surface hardness and scratch resistance that the elastomer alone cannot achieve.

Inventive Principle:
Principle #40Composite materials

Data Source

PatentEP2942370B1Thermoplastic polymer composition, sheet or film, and multi-layered film
Publication Date: 2017.05.31 KURARAY CO LTD
  • EP2942370B1 patent drawingFigure 1~2
  • EP2942370B1 patent drawingFigure 3
  • EP2942370B1 patent drawing

AI summary

Provided are a thermoplastic polymer composition having good mold processability, flexibility, rubber elasticity, scratch resistance, abrasion resistance, transparency, ease of coating, and mechanical properties when formed into a sheet or film, a sheet or film produced using the thermoplastic polymer composition, and a multi-layered film. The thermoplastic polymer composition includes (I) a block copolymer having a number average molecular weight of 30,000 to 200,000, or a hydrogenated product thereof, which has a polymer block (A) mainly composed of α-methylstyrene units and a polymer block (B) mainly composed of conjugated diene compound units or isobutylene units, (II) an acryl-based polymer, and (III) a softening agent at a ratio satisfying the formulae (1) and (2) as described in claim 1, and has a sea-island structure in which the components (II) are dispersed in the form of particles in a continuous phase including the component (I), in which the average dispersed particle diameter of the dispersed particles of the components (II) is 200 nm or less, and 35% by mass or more of the dispersed particles have dispersed particle diameters of less than 60 nm.