Reinforced Polyalkylene Terephthalate Composition Warpage Reduction
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Solution Overview
Problem
Glass fiber-reinforced polyalkylene terephthalate (PAT) materials face challenges with high processing temperatures, low melt flowability, and warpage issues, limiting their application in injection molding, blow molding, and extrusion processes, especially when used in composite structures with other thermoplastics like PVC.
Innovation Solution
A composition of polyalkylene terephthalate (PBT or PET) modified with a terpolymer of alkylene diol, isophthalic acid, and terephthalic acid (PAIT) and reinforced with glass fibers, which reduces the melting point and enhances melt flowability, resulting in lower processing temperatures and reduced warpage, achieved through compounding these components under specific conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If glass fiber content is increased to improve mechanical strength, then strength is improved, but processability deteriorates (high processing temperature, low melt flowability)
Solution Approach 1:
The patent modifies the chemical composition parameters of PBT by incorporating specific amounts of PET (10-40 wt%) and TPC (5-30 wt%) to change the melting point and melt flow characteristics. This compositional parameter change allows the material to maintain high glass fiber content (30-60 wt%) while achieving lower processing temperatures (reduced by 20-50°C) and improved melt flowability, thus resolving the contradiction between strength and processability
Solution Approach 2:
The patent creates a composite polymer system combining PBT, PET, and TPC with glass fiber reinforcement. This multi-component composite structure leverages the complementary properties of each polymer: PBT provides base mechanical strength, PET enhances thermal stability and reduces warpage, while TPC improves melt flowability. The synergistic combination allows high glass fiber content to be processed effectively while maintaining enhanced mechanical strength
2Ease of operation
If processing temperature is increased to improve melt flowability, then melt flowability is improved, but warpage increases
Solution Approach 1:
The patent changes the thermal parameters of the polymer system by adding PET and TPC, which have different thermal expansion coefficients and melting characteristics compared to pure PBT. This parameter modification enables the material to achieve adequate melt flowability at lower temperatures, thereby reducing thermal stress and warpage during processing while maintaining operational ease
Solution Approach 2:
The patent optimizes the local composition ratios of PBT, PET, and TPC to achieve uniform heat distribution and controlled crystallization behavior during processing. This local compositional control ensures consistent melt flow characteristics throughout the material, allowing processing at moderate temperatures that minimize warpage while maintaining adequate flowability for molding operations
3Productivity
If processing temperature is reduced to lower cycle time, then productivity is improved, but melt flowability decreases
Solution Approach 1:
The patent modifies the rheological parameters of the polymer system by incorporating TPC, which has superior low-temperature flow characteristics. This parameter change allows the material to maintain high melt flowability at reduced processing temperatures, enabling shorter cycle times and improved productivity without sacrificing ease of operation or molding quality
4Weight of moving object
If glass fiber content is increased to replace metal inserts, then weight is reduced, but adhesion to other thermoplastics deteriorates
Solution Approach 1:
The patent creates a multi-phase composite system where PBT serves as the continuous matrix, glass fiber provides reinforcement and weight reduction, while PET and TPC phases enhance interfacial adhesion properties. This composite structure maintains the weight advantage of glass fiber reinforcement (replacing metal inserts) while the specific polymer combination improves bonding to other thermoplastics like PVC, thus resolving the adhesion deterioration issue
Solution Approach 2:
The patent optimizes the local distribution and interface characteristics of glass fiber within the PBT/PET/TPC matrix to enhance adhesion. By controlling the compositional ratios and processing conditions, the patent creates favorable interfacial regions that improve bonding to other thermoplastics while maintaining the overall weight reduction benefit of high glass fiber content
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 modified fiber-reinforced PAT exhibits superior processability with lower processing temperatures, higher melt flowability, and improved mechanical properties, enabling the production of shaped articles with reduced warpage and enhanced adhesion when used alone or in composite structures with PVC, while maintaining mechanical integrity.
Implementation Method 1
the low melting point (and thus processing temperature) and/or higher melt flowability also decreases cycle-time for making the articles
Implementation Method 2
increasing melt flowability will be beneficial if the melt flowability can be increased via modification
Data Source
AI summary
A composition comprises polyalkylene terephthalate and terpolymer of alkylene diol, isophthalic acid and terephthalic acid, and polyalkylene terephthalate reinforcing fiber. The composition may be used to form an article, alone or with other thermoplastic material, at lower processing temperature, with higher melt flowability. The article formed is characterized with lower warpage and improved mechanical properties. The article may be useful for automotive, electrical, household, construction, and industrial applications. A method of preparing such thermoplastic polyester is also disclosed.