Vinyl Chloride Polymer Film Polyester Flow Aid
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Solution Overview
Problem
The use of vinyl chloride copolymers as flow aids in PVC films improves thermoformability but reduces thermal stability and increases the tendency to stick, necessitating complex additive formulations that are costly to manufacture.
Innovation Solution
Incorporating a small amount of semicrystalline or amorphous polyester as a flow aid, which provides better thermoformability without the need for high amounts of vinyl chloride/vinyl acetate copolymer, allowing for simpler additive formulations and improved thermal stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If vinyl chloride copolymer is used as flow aid to improve thermoformability, then thermoformability is improved, but thermal stability is reduced and sticking tendency increases
Solution Approach 1:
The invention changes the chemical composition parameter by replacing vinyl chloride copolymer with polyester, specifically using polyesters with controlled crystallization behavior (crystallization half-life time of at least 5 minutes from molten state). This parameter change maintains thermoformability while eliminating the thermal stability issues associated with vinyl chloride copolymers
Solution Approach 2:
The invention uses a small amount of polyester (0.1 to less than 5% by weight) as a temporary flow aid that performs its function during processing and then does not interfere with the final product properties. This minimal addition approach reduces the need for complex additive formulations
2Ease of operation
If vinyl chloride copolymer is used as flow aid, then thermoformability is improved, but complex additive formulations are required increasing manufacturing cost
Solution Approach 1:
The invention extracts and eliminates the need for complex additive formulations by using polyester as a simpler alternative. The polyester component alone provides the necessary flow aid functionality, allowing the removal of multiple other additives that would be required when using vinyl chloride copolymer, thereby simplifying the overall formulation and reducing manufacturing complexity
Solution Approach 2:
By changing the flow aid material from vinyl chloride copolymer to polyester with specific crystallization properties, the invention achieves the same thermoformability improvement with a simpler, more cost-effective formulation that requires fewer additional additives
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 use of amorphous or semicrystalline polyester as a flow aid in VCP films achieves comparable or better thermoformability than vinyl chloride/vinyl acetate copolymer, reducing manufacturing costs and enhancing thermal stability, making the films suitable for industrial-scale thermoformed packaging production.
Implementation Method 1
The film of the invention is produced by plastifying and then extruding a mixture comprising vinyl chloride polymer, polyester, and additives
Implementation Method 2
a semicrystalline or amorphous polyester with a crystallization halftime from the molten state of at least 5 min
Data Source
AI summary
The invention relates to a film made of a vinyl chloride polymer mixture that, in addition to the conventional additives, contains 0.1 to less than 5 wt % of a semicrystalline or amorphous polyester, has a good thermal formability, and is suitable for the packaging of bulk goods. The film is produced by extruding or by calendering the plastified vinyl chloride polymer mixture, optionally followed by inline/offline stretching and, optionally, thermally formed immediately thereafter.