Optical Layer Resin Composition for Uniform Light Absorber Dispersion
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Solution Overview
Problem
The existing resin compositions used to form optical layers with high melting point light absorbers often result in uneven distribution and poor external appearance due to the inability of these absorbers to dissolve and disperse uniformly, affecting the reliability and appearance of the resulting molded bodies and cover members.
Innovation Solution
A resin composition comprising a polycarbonate-based resin with a specific molecular weight range and a mixture of visible light absorbers, where the weight-average molecular weight to number-average molecular weight ratio is between 1.0 and 2.0, and the viscosity at 260°C is between 600 Pa·s and 3500 Pa·s, ensuring uniform dispersion of high melting point absorbers, thereby enhancing solubility and dispersibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a multilayer structure with different resin materials is used to achieve both rigidity and flexibility, then mechanical properties are improved, but manufacturing complexity increases
Solution Approach 1:
The patent applies composite materials by combining a rigid resin layer (polycarbonate or polyethylene terephthalate) with a flexible resin layer (polyvinylidene chloride copolymer) in a multilayer structure. This composite approach achieves both rigidity and flexibility in a single integrated material system, improving mechanical properties while the specific formulation and lamination process manage manufacturing complexity.
2Reliability
If conventional resin materials are used to ensure chemical stability, then reliability is improved, but affinity with electrophotographic toner deteriorates
Solution Approach 1:
The patent applies local quality by creating a flexible resin layer with specific local properties (polyvinylidene chloride copolymer with 30-80% vinyl chloride content) that has high affinity for electrophotographic toner. This localized functional layer works in conjunction with the rigid base layer, allowing the system to maintain chemical stability while providing the necessary toner affinity through the specially formulated surface layer.
3Strength
If the number of layers is increased to achieve both rigidity and flexibility, then mechanical properties are improved, but the number of manufacturing steps increases
Solution Approach 1:
The patent achieves the balance between mechanical properties and manufacturing efficiency through a optimized composite structure with specifically controlled layer thicknesses (rigid layer: 5-50 μm, flexible layer: 1-10 μm). This composite material approach provides both rigidity and flexibility in a two-layer configuration, avoiding the need for additional layers while maintaining manufacturing efficiency through a streamlined lamination process.
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 solution allows for the formation of optical layers with excellent external appearance and reliability, ensuring that the molded bodies and cover members exhibit improved light transmission and mechanical properties while maintaining the desired color tone and impact resistance.
Implementation Method 1
a visible light absorber for absorbing visible light... allowing the transmission of light having a wavelength in the specific wavelength range and being capable of reducing the transmission of light having a wavelength in another specific wavelength range
Implementation Method 2
there is a problem that the external appearance of the optical layer, that is, the cover member, thus obtained is impaired because this light absorber cannot be uniformly dissolved and dispersed in the resin composition
Data Source
Figure 1~2
AI summary
A resin composition of the present invention is used in an optical layer 10 provided with a first layer (base material layer 1) including a polycarbonate-based resin and a visible light absorber for forming the first layer. The visible light absorber includes a plurality of kinds of light absorbers, and a melting point of a first light absorber having the lowest melting point is equal to or higher than 200°C, in which a melting point of a second light absorber having the highest melting point is equal to or lower than 330°C. The resin composition is such that the viscosity at 260°C obtainable when a shear rate is 243.2 [1/sec] is equal to or more than 400 Pa·s and equal to or less than 3500 Pa·s.