Polycarbonate Resin Composition for Automotive Button Housings
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Solution Overview
Problem
In-vehicle infotainment device button housings made with gray-colored materials experience reduced light transmittance and luminance, necessitating a polycarbonate resin composition with improved light-reflecting and light-shielding properties while maintaining heat resistance, impact resistance, and mechanical strength.
Innovation Solution
A polycarbonate resin composition comprising 60-70 wt% polycarbonate resin, 4-10 wt% rubber-modified vinyl-based graft copolymer, 3-11 wt% styrene-based copolymer, 15-25 wt% titanium dioxide, and 2-3 wt% mineral filler, with specific molecular weights and particle sizes, providing excellent light reflectance and transmittance characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If gray-colored material is applied to button housing, then light shielding property is improved, but light transmittance and luminance are reduced
Solution Approach 1:
The patent uses a composite resin composition comprising polycarbonate resin, rubber-modified vinyl-based graft copolymer, styrene-based copolymer, titanium dioxide, and mineral filler. This composite structure achieves both light shielding and high luminance by combining materials with complementary properties - the polymers provide structural integrity while titanium dioxide enhances light reflection and shielding capability.
Solution Approach 2:
The patent optimizes specific parameter ranges including rubber-modified vinyl-based graft copolymer content (4-10 parts by weight per 100 parts polycarbonate resin), styrene-based copolymer content (3-11 parts), titanium dioxide content (15-25 parts), and mineral filler content (2-3 parts). These parameter adjustments achieve the optimal balance between light shielding property and luminance.
2Illumination intensity
If titanium dioxide content is increased to improve light reflectance, then light-reflecting property is improved, but processability and moldability may deteriorate
Solution Approach 1:
The patent precisely controls titanium dioxide content within 15-25 parts by weight per 100 parts polycarbonate resin, and adjusts processing temperature to 220-280°C with mold temperature of 20-40°C. This parameter optimization ensures high light reflectance while maintaining adequate processability and moldability.
Solution Approach 2:
The patent incorporates mineral filler (2-3 parts by weight) with specific particle size distribution to complement titanium dioxide's light-reflecting function while improving overall processability. The mineral filler compensates for potential processability issues caused by high titanium dioxide content through its lubricating effect and flow enhancement.
3Strength
If rubber-modified vinyl-based graft copolymer and styrene-based copolymer are added to improve impact resistance, then impact resistance is improved, but manufacturing complexity increases
Solution Approach 1:
The patent creates a multi-component composite system where rubber-modified vinyl-based graft copolymer (4-10 parts) and styrene-based copolymer (3-11 parts) work synergistically with polycarbonate resin. The rubber-modified component provides primary impact resistance through energy absorption, while the styrene-based copolymer enhances overall mechanical strength and processability, achieving high impact resistance through material composition rather than complex manufacturing processes.
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
The composition achieves complete light shielding with high light reflectance and zero transmittance, along with enhanced heat resistance, impact strength, and mechanical properties, suitable for automotive molded articles like button housings and inner panels.
Implementation Method 1
the polycarbonate resin composition may have a light reflectance of 95% or more at a wavelength of 400 to 700 nm, and a light transmittance of 0% at a wavelength of 400 to 700 nm
Implementation Method 2
15 to 25 wt % of titanium dioxide
Data Source
AI summary
The present disclosure relates to a polycarbonate resin composition having excellent light-reflecting and light-shielding properties, and an automotive molded article produced using the same. The polycarbonate resin composition includes: 60 to 70 wt % of a polycarbonate resin; 4 to 10 wt % of a rubber-modified vinyl-based graft copolymer; 3 to 11 wt % of a styrene-based copolymer; 15 to 25 wt % of titanium dioxide; and 2 to 3 wt % of a mineral filler.