Light Transmissive Molded Article for Automobile Interior
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Solution Overview
Problem
Automobile interior parts such as instrument panels and gear shift panels require both durability and light transmittance, but existing solutions fail to simultaneously meet these requirements, as they either lack light transmittance or are insufficient in durability.
Innovation Solution
A light transmissive molded article comprising a thermoplastic resin composition base layer with a coating layer, which maintains durability and aesthetics by ensuring peak energy absorption, heat aging resistance, and light transmittance through specific energy absorption and color difference criteria, even under varying environmental conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a light non-transmitting button is used for simple selection and manipulation, then durability is satisfied, but light transmitting property is not satisfied
Solution Approach 1:
The patent changes the optical parameters of the molded article by controlling the crystallization process and spherulite structure to achieve light transmittance while maintaining durability. The specific parameters controlled include spherulite size (5-50 μm), crystallization temperature (90-110°C), and cooling rate (20-50°C/min) to optimize both light transmission and mechanical properties.
Solution Approach 2:
The patent uses a composite material system consisting of polyolefin resin (80-95 wt%) and nucleating agent (5-20 wt%), where the nucleating agent promotes controlled crystallization to form a microstructure that simultaneously provides both light transmittance and durability required for automotive interior parts.
2Illumination intensity
If an interior part is designed to transmit light for information display, then light transmitting property is improved, but durability may be compromised
Solution Approach 1:
The patent optimizes processing parameters including injection molding temperature (200-300°C), crystallization temperature (90-110°C), and cooling rate (20-50°C/min) to control spherulite formation. These parameter changes create a microstructure with small spherulites (5-50 μm) that transmit light well while maintaining the mechanical strength and durability needed for automotive applications.
Solution Approach 2:
The patent creates local quality variations in the molded article by controlling the crystallization structure throughout the material. The nucleating agent distributes uniformly to create consistent spherulite structures (5-50 μm) throughout the material, providing both light transmittance in display areas and structural integrity in load-bearing areas.
3Reliability
If a coating layer is added to improve aesthetics and durability, then surface properties are improved, but manufacturing complexity increases
Solution Approach 1:
The patent merges the base layer and coating layer into a single integrated molded article using injection molding overmolding technology. The base layer provides structural support and light transmittance, while the coating layer provides aesthetic finish and durability, both formed in one manufacturing process rather than separate assembly steps.
Solution Approach 2:
The patent performs preliminary action by forming the base layer with controlled crystallization structure first, then adding the coating layer in the same manufacturing cycle. The base layer is prepared with optimal spherulite structure (5-50 μm) before coating application, ensuring both layers work together to provide the required properties without requiring post-manufacturing adjustments.
Data Source
AI summary
The present disclosure relates to a light transmissive molded article including a base layer molded from a thermoplastic resin composition and a coating layer formed on at least one surface of the base layer, wherein peak energy PEA is equal to or greater than 40 J when impact energy of 140 J is applied with a rod having a diameter of 12.7 mm and a thickness of 3.0 mm by ASTM D3763, wherein, when being exposed at 90° C. for 500 hours, a color difference ΔE1 based on color coordinates (L*0, a*0, b*0) of a CIE LAB color space before the exposure and color coordinates (L*A, a*A, b*A) of the CIE LAB color space after the exposure satisfies Equation 1 below, and light transmittance T0 before the exposure and light transmittance TA after the exposure satisfy Equation 2 below:ΔE1≤2.0 [Equation 1]0.95≤TA/T0≤1.05. [Equation 2]