Zipper Tape Resin Composition for Low-Temperature Point Sealing
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Solution Overview
Problem
The existing manufacturing processes for bags with zipper tapes, particularly those with polypropylene engagement portions, face speed constraints due to the high melting point of polypropylene, leading to longer point sealing times and potential wrinkles when increasing temperature.
Innovation Solution
A zipper tape with elongated shape and engagement portions formed from a resin composition having specific fusion enthalpy and tensile modulus of elasticity values, allowing for improved flattening properties and potentially omitting or shortening the point sealing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the temperature of the point sealing process is increased to shorten processing time, then the processing speed is improved, but wrinkles are generated on the film surface
Solution Approach 1:
The patent changes the material parameters of the engagement portion by using a resin composition with specific properties (low melting point, low tensile modulus) to enable point sealing at lower temperatures, thus avoiding wrinkles while maintaining fast processing speed
Solution Approach 2:
The patent uses a composite resin composition comprising polypropylene and a specific resin (with melting point 100-120°C and tensile modulus 200-400 MPa) to create an engagement portion that has optimized thermal and mechanical properties for rapid low-temperature sealing
2Loss of time
If the temperature of the point sealing process is increased to shorten processing time, then the processing time is reduced, but the film heat resistance is exceeded
Solution Approach 1:
The patent changes the melting point parameter of the engagement portion material to 100-120°C, which is lower than the film's heat resistance, enabling point sealing to be performed at temperatures that do not damage the film while still achieving rapid sealing
3Strength
If polypropylene is used for the engagement portion, then the material strength is improved, but the point sealing process time is extended
Solution Approach 1:
The patent creates a composite resin composition that combines polypropylene (for strength) with another resin having melting point 100-120°C and tensile modulus 200-400 MPa (for low-temperature deformability), achieving both high strength and fast point sealing
Solution Approach 2:
The patent applies different material properties to different parts of the zipper tape: the engagement portion uses the specialized resin composition for low-temperature sealing, while other parts can use standard materials, optimizing both strength and sealing speed
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 improved flattening properties of the zipper tape enable point sealing at lower temperatures, reducing processing time or eliminating the need for the point sealing process, thereby enhancing manufacturing efficiency.
Implementation Method 1
the resin composition having fusion enthalpy ΔH 120 in a temperature range of higher than or equal to 120 degrees C measured by differential scanning calorimetry (DSC) of less than 30 J/g
Data Source
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AI summary
A zipper tape having an elongated shape includes, in a cross-sectional shape thereof: a pair of base strips; and engagement portions projecting from respective opposing surfaces of the pair of base strips and being engageable with each other, in which at least the engagement portions each are formed with a resin composition including polypropylene, the resin composition having fusion enthalpy ΔH120 in a temperature range of higher than or equal to 120 degrees C measured by differential scanning calorimetry (DSC) of less than 30 J/g, and has tensile modulus of elasticity of less than or equal to 600 MPa.