Plastics Moulding Composition for Display Covers
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Solution Overview
Problem
Existing plastics moulding compositions for display covers face challenges in achieving high impact resistance, optical clarity, and chemical resistance while maintaining low haze and clouding, especially in the context of miniaturization and automated injection-moulding processes for thin components.
Innovation Solution
A plastics moulding composition comprising a combination of poly(meth)acrylate A and impact-modified poly(meth)acrylate B, characterized by a die swell of at least 15% and a melt flow rate of at least 10 ml per 10 minutes, which allows for efficient processing of mouldings with high impact resistance, excellent optical properties, and resistance to conventional cleaning agents without stress cracks or haze.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If impact-modified plastics moulding compositions are used to improve impact resistance, then impact resistance is improved, but haze values increase and clouding occurs
Solution Approach 1:
The patent applies parameter changes by precisely controlling the melt flow rate (MFR) of the poly(meth)acrylate component within the range of 10-50 ml/10min and the die swell within 15-40%. These parameter optimizations resolve the contradiction by finding the optimal balance point where impact resistance is sufficiently improved while haze and clouding are minimized to acceptable levels.
Solution Approach 2:
The patent uses composite materials by combining poly(meth)acrylate with specific impact modifiers (such as core-shell rubber particles or acrylic ester copolymers) in carefully controlled ratios. This composite approach allows the material to achieve both high impact resistance and acceptable optical clarity, resolving the contradiction between these two properties.
2Ease of operation
If conventional cleaning compositions (alcohol-containing solutions) are used to clean display covers, then cleaning effectiveness is achieved, but stress cracks form on the material surface
Solution Approach 1:
The patent modifies the chemical composition parameters of the moulding material by incorporating specific impact modifiers and optimizing the poly(meth)acrylate formulation. This changes the material's chemical resistance properties, allowing it to withstand alcohol-containing cleaning solutions without forming stress cracks, while maintaining cleaning effectiveness.
3Productivity
If automated injection-moulding processes are used to increase productivity, then production efficiency is improved, but downstream operations (such as sprue removal) are still required
Solution Approach 1:
The patent applies the self-service principle through self-ejecting moulding designs enabled by optimized material flow characteristics. The controlled die swell and melt flow rate allow the moulding to automatically eject from the mould cavity after cooling, eliminating the need for manual or mechanical sprue removal operations and achieving true automated production.
4Length of moving object
If gate diameter is reduced to meet miniaturization requirements, then device size is reduced, but moulding quality (transparency and surface finish) deteriorates
Solution Approach 1:
The patent optimizes the rheological parameters of the moulding material, specifically controlling the die swell within 15-40% and melt flow rate within 10-50 ml/10min. These parameter changes enable the material to maintain excellent flow characteristics and filling behavior through small gates, ensuring high moulding quality (transparency and surface finish) even with miniaturized gate dimensions.
Data Source
AI summary
The present invention relates to a plastics molding composition encompassing at least one poly(meth)acrylate A) and at least one impact-modified poly(meth)acrylate B), wherein the die swell of the plastics molding composition is at least 15%, measured at 5 MPa and 2200C to DIN 54811 (1984), and the melt flow rate of the poly(meth)acrylate A) is at least 10 ml per 10 minutes, measured to ISO 1133 at 2300C with a load of 3.8 kg. The present invention also describes moldings which encompass the plastics molding composition described above, and processes for the production of the said moldings.