Polyamide Film Roll Dimensional Stability During Heat Sterilization
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Solution Overview
Problem
Conventional biaxially oriented polyamide based resin film rolls experience S-shaped curl phenomenon during heat sterilization, leading to appearance deterioration and poor lamination properties, while methods to address this often compromise toughness and pinhole resistance.
Innovation Solution
A film roll with tightly controlled boiling water shrinkage percentage and refraction index variability, achieved through specific processing conditions including biaxial stretching, precise temperature control, and uniform resin chip composition, ensures smooth bag forming and high yield ratios without curling issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If extreme high temperature thermal fixation or excess thermal relaxation is applied to enhance dimensional stability, then S-shaped curl phenomenon is reduced, but toughness and pinhole resistance are deteriorated
Solution Approach 1:
The patent applies parameter changes by precisely controlling boiling water shrinkage percentage (3-7%) and refraction index (1.510-1.525) within specific numeric ranges. This resolves the contradiction by finding optimal parameter values that achieve dimensional stability without requiring extreme thermal treatment that would compromise mechanical properties.
Solution Approach 2:
The patent uses refraction index as a copy indicator or proxy measure for molecular orientation and crystallinity. By controlling refraction index within a specific range, the patent indirectly controls dimensional stability and prevents S-shaped curl without needing extreme thermal fixation, thus preserving toughness and pinhole resistance.
2Manufacturing precision
If average values of boiling water shrinkage percentage and refraction index are controlled within specified ranges, then S-shaped curl phenomenon is prevented, but variation within a film roll causes wrinkle during lamination
Solution Approach 1:
The patent implements feedback control by measuring boiling water shrinkage percentage and refraction index at multiple positions across the film roll width and length. This feedback information is used to adjust processing conditions to ensure uniformity within ±2%, preventing wrinkles during lamination while maintaining overall dimensional stability.
Solution Approach 2:
The patent divides the film roll into multiple measurement zones (center, edges, and intermediate positions) to separately control and monitor dimensional properties. This segmentation approach identifies and corrects local variations that would otherwise cause wrinkles during lamination processing.
3Strength
If biaxially oriented polyamide based resin film is used for packaging, then gas-barrier and toughness are improved, but S-shaped curl phenomenon occurs during heat sterilization
Solution Approach 1:
The patent changes key parameters by controlling boiling water shrinkage percentage (3-7%) and refraction index (1.510-1.525) within optimized ranges. This resolves the contradiction by achieving dimensional stability during heat sterilization while preserving the inherent toughness and gas-barrier properties of biaxially oriented polyamide film.
Solution Approach 2:
The patent employs composite control strategies by combining multiple property controls (shrinkage, refraction index, molecular orientation, crystallinity) to achieve overall dimensional stability. This composite approach maintains the excellent mechanical properties of polyamide film while preventing S-shaped curl during sterilization.
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 solution enables polyamide based resin film rolls with excellent toughness, pinhole resistance, and improved lamination properties, preventing S-shaped curling and ensuring high-quality packaging without compromising mechanical properties.
Implementation Method 1
A biaxially oriented polyamide based resin film composed of nylon in major components
Implementation Method 2
the method needs an extremely high temperature in thermal fixation or excess thermal relaxation after stretching
Implementation Method 3
adjust a biaxially oriented polyamide based resin film to a specified value of product of its boiling water shrinkage percentage
Data Source
AI summary
A polyamide based resin film roll is provided. The polyamide based resin film roll comprising: a first sample cutout portion within 2 m from the winding end of film; and a final cutout portion within 2 m from the winding start of film, wherein when a sample cutout portion is set up in approximately every 100 m from the first sample cutout portion, in all samples cut out from each of the cutout portions, mechanical properties such as boiling water shrinkage percentage and refraction index in the thickness direction are adjusted within a given range of variation width.