Oriented Thermoplastic Polyester Sheet for Low Expansion Gutters
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Solution Overview
Problem
Existing methods for producing oriented thermoplastic polyester resin sheets struggle to achieve a balance between tensile strength, tensile modulus, heat resistance, and low linear expansion coefficient, while also ensuring impact resistance and ease of handling, particularly for applications like gutters.
Innovation Solution
A process involving pultrusion-drawing and uniaxial drawing of thermoplastic polyester resin sheets within specific temperature ranges, followed by heatsetting and annealing, to produce sheets with enhanced mechanical properties and controlled expansion coefficients, and laminating a thermoplastic resin layer on the surfaces for improved durability and impact resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If pultrusion-molding is performed in the temperature range from glass transition temperature -20°C to glass transition temperature +20°C to achieve high tensile strength and modulus of elasticity, then the oriented polyester resin sheet has excellent strength and modulus of elasticity, but when the sheet is heated to the glass transition temperature or higher, the modulus of elasticity falls suddenly
Solution Approach 1:
The patent changes the processing temperature parameter from the conventional glass transition temperature range to a higher temperature range (melting point -50°C to melting point -20°C), which fundamentally alters the molecular orientation and crystalline structure of the polyester resin, enabling the sheet to maintain high modulus of elasticity even when heated to the glass transition temperature or higher
Solution Approach 2:
The patent creates a composite structure within the polyester resin sheet by controlling the crystalline phase formation at elevated temperatures, resulting in a multi-phase material structure that combines high-strength oriented regions with heat-resistant crystalline regions, thereby simultaneously achieving high tensile strength and improved heat resistance
2Reliability
If rigid vinyl chloride based resin is used for gutters to achieve water resistance, flame resistance, and mechanical properties, then the resin is excellent in these properties and is relatively inexpensive, but the linear expansion coefficient is as large as 7.0×10−5 (1/° C.), requiring joints to absorb stretch and shrinkage
Solution Approach 1:
The patent changes the material composition parameter by replacing rigid vinyl chloride based resin with thermoplastic polyester resin that has been processed through pultrusion-molding and uniaxial drawing at specific temperature ranges, fundamentally altering the thermal expansion characteristics while maintaining mechanical properties
Solution Approach 2:
The patent creates a composite structure within the polyester resin by controlling molecular orientation and crystalline phase distribution through multi-stage processing, resulting in a material that exhibits low linear expansion coefficient while maintaining water resistance, flame resistance, and mechanical strength
3Temperature
If the linear expansion coefficient of rigid vinyl chloride based resin molded bodies is reduced by adding mica and calcium carbonate, then the linear expansion coefficient becomes lower, but if the added amount is made high, the impact resistance and durability fall
Solution Approach 1:
The patent extracts and eliminates the need for mica and calcium carbonate additives by using thermoplastic polyester resin as the base material and controlling its molecular structure through pultrusion-molding and uniaxial drawing processes, achieving low linear expansion coefficient without compromising impact resistance and durability
Solution Approach 2:
The patent changes the fundamental material parameter from vinyl chloride based resin to thermoplastic polyester resin, and further changes the molecular orientation parameter through controlled drawing processes, achieving low linear expansion coefficient inherently without requiring large amounts of inorganic fillers that would harm impact resistance
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 resulting oriented thermoplastic polyester resin sheets exhibit superior tensile strength, modulus, and heat resistance, with a low linear expansion coefficient, making them suitable for exterior building members like gutters, while also improving impact resistance and handling ease.
Implementation Method 1
pultrusion-drawing a thermoplastic polyester resin sheet in an amorphous state at a temperature from the glass transition temperature of the oriented thermoplastic polyester resin −20° C. to the glass transition temperature of the thermoplastic polyester resin +20° C.; and then drawing the resultant uniaxially at a temperature higher than the temperature for the pultrusion-drawing
Implementation Method 2
followed by heatsetting and annealing, to produce sheets with enhanced mechanical properties and controlled expansion coefficients
Data Source
AI summary
The present invention provides a process for producing an oriented thermoplastic polyester resin sheet which is excellent in tensile strength, tencile modulas and heat resistance, and a light laminate-molded body using the same, which has a low linear expansion coefficient and is excellent in impact resistance, durability, easiness of handling, productivity, and others. A process for producing an oriented thermoplastic polyester resin sheet, which includes: pultrusion-drawing a thermoplastic polyester resin sheet in an amorphous state at a temperature from the glass transition temperature of the thermoplastic polyester resin −20° C. to the glass transition temperature of the thermoplastic polyester resin +20° C.; and then drawing the resultant uniaxially at a temperature higher than the temperature for the pultrusion-drawing. A laminate-molded body, wherein a thermoplastic resin layer is laminated on each of the surfaces of the resultant oriented thermoplastic polyester resin sheet.