Thermoplastic Resin Laminate for Optical Sheet Pattern-Formability
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Solution Overview
Problem
Current methods for producing optical sheets with enhanced brightness and viewing angle, such as roller embossing of thermoplastic resins, face limitations in pattern-formability and transparency due to the properties of methacrylic and polycarbonate resins, which affect the consistency and quality of liquid crystal display devices.
Innovation Solution
A thermoplastic resin laminate is developed by laminating a vinyl copolymer resin layer on a methacrylic resin layer, composed of specific (meth)acrylate and aliphatic vinyl structural units, to improve transparency, low birefringence, and pattern-formability, allowing for better adhesion and heat resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If methacrylic resin is used for roller embossing to achieve good transparency and low birefringence, then optical quality is improved, but pattern-formability deteriorates because the resin cannot run through to deep portions of the grooves at low temperature
Solution Approach 1:
The patent changes the chemical composition parameters of the resin by using a copolymer containing both methacrylic units (for transparency) and vinyl units with cyclic structures (for fluidity). This compositional parameter change allows the resin to maintain good optical properties while achieving sufficient fluidity at low temperatures for deep groove penetration during roller embossing.
Solution Approach 2:
The patent creates a composite resin system by copolymerizing methacrylic monomers with vinyl monomers containing cyclic structures. This composite material approach combines the advantages of both resin types: the transparency and low birefringence of methacrylic resin with the enhanced fluidity provided by the vinyl-cyclic units, resolving the contradiction between optical quality and pattern-formability.
2Manufacturing precision
If polycarbonate resin is used for roller embossing to improve pattern-formability due to high fluidity at low temperature, then manufacturing precision is improved, but transparency and birefringence deteriorate
Solution Approach 1:
The patent modifies the resin composition parameters by limiting polycarbonate content to 5% or less while maintaining methacrylic units as the primary component (70-95%). This parameter control ensures sufficient fluidity for pattern-forming while preserving the transparency and low birefringence characteristics of methacrylic-based resins.
Solution Approach 2:
The patent formulates a composite resin composition that primarily uses methacrylic resin with small additions of polycarbonate (≤5%) and vinyl-cyclic units. This composite approach leverages the high fluidity of polycarbonate to improve pattern-formability while keeping the dominant methacrylic component responsible for optical quality.
3Manufacturing precision
If the processed thermoplastic resin is shaped at low viscosity to enhance pattern-formability, then manufacturing precision is improved, but cooling efficiency deteriorates causing the pattern to restore to original shape
Solution Approach 1:
The patent changes the viscosity-temperature relationship parameters of the resin through compositional modification. The vinyl-cyclic units and controlled copolymer structure create a resin that maintains low viscosity at processing temperature for good pattern-formability, yet exhibits rapid viscosity increase upon cooling, enabling effective pattern fixation without restoration.
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 laminate achieves excellent transparency, low birefringence, and high pattern-formability, making it suitable for use as a front plate, light guide plate, or prism sheet in liquid crystal display devices with improved optical performance.
Implementation Method 1
the vinyl copolymer resin layer being produced by polymerizing a (meth)acrylate monomer and an aromatic vinyl monomer, followed by hydrogenation
Implementation Method 2
polymerizing a (meth)acrylate monomer and an aromatic vinyl monomer, followed by hydrogenation
Implementation Method 3
the resin is compressed and cooled by both of the rollers, whereby the specific shape is imparted to the surface of the molded resin sheet
Implementation Method 4
the resin is compressed and cooled by both of the rollers
Implementation Method 5
a thermoplastic resin whose fluidity considerably lowers at low resin temperature
Data Source
AI summary
To provide a thermoplastic resin laminate which is used as a transparent substrate material or a transparent protective material and which is excellent in transparency, birefringence, and pattern-formability. The thermoplastic resin laminate is a synthetic resin laminate formed of a methacrylic resin (B) layer, and a vinyl copolymer resin (A) layer laminated on one side or both sides of the methacrylic resin (B) layer, wherein the vinyl copolymer resin (A) contains a (meth)acrylate structural unit (a) represented by a specific formula and an aliphatic vinyl structural unit (b) represented by a specific formula; in which the ratio of the sum of the (meth)acrylate structural units (a) and the aliphatic vinyl structural units (b) is 90 to 100 mol% with respect to all the structural units that form the vinyl copolymer resin (A); in which the ratio by mole of the (meth)acrylate structural unit (a) to the aliphatic vinyl structural unit (b) is 65 : 35 to 85 : 15; and in which the methacrylic resin (B) contains a structural unit having no benzene ring in an amount of 90 mol% or more with respect to all the structural units thereof.