Stretched Polyamide Film Surface Orientation Control
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Solution Overview
Problem
Conventional stretched polyamide films for packaging face challenges in achieving high adhesive and lamination strength without becoming brittle, while maintaining mechanical properties and resistance to heat and impact.
Innovation Solution
A stretched polyamide film with a surface layer composed of nylon 6, where the molecular orientation and crystallization are controlled within specific ranges using FT-IR polarized ATR measurements, incorporating a block copolymer or graft polymer to relax orientation and maintain crystallinity, and adjusting the heat fixation temperature to balance lamination strength and heat resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If a layer of amorphous resin or highly-adherent resin is laminated on the surface layer by coating or coextrusion, then adhesive property is improved, but production steps become complicated and blocking occurs
Solution Approach 1:
The invention extracts the adhesive function from a separate laminated layer and integrates it into the surface layer itself by controlling the molecular orientation and crystallization state of nylon 6. This eliminates the need for additional amorphous resin layers while maintaining excellent adhesive properties.
Solution Approach 2:
The invention changes the physical and chemical parameters of the surface layer by controlling the orientation factor (0.25-0.35) and crystallization degree (15-30%). These parameter adjustments enable the surface layer to achieve high adhesive strength without requiring additional laminated layers, thus simplifying the production process.
2Object-generated harmful factors
If heat fixation temperature is increased to disrupt orientation in the surface layer, then adhesive property is improved, but the film becomes brittle due to excessive heat treatment
Solution Approach 1:
The invention optimizes the heat fixation temperature to a specific range (200-230°C) that achieves the desired orientation factor (0.25-0.35) and crystallization degree (15-30%) without excessive heat treatment. This controlled parameter adjustment improves adhesive property while preventing the film from becoming brittle.
Solution Approach 2:
The invention uses FT-IR polarized ATR measurement to monitor and control the orientation factor and crystallization degree during the heat fixation process. This feedback mechanism ensures that the film achieves optimal adhesive properties while maintaining mechanical strength by preventing excessive orientation disruption.
3Strength
If semi-aromatic polyamide is added to aliphatic polyamide, then strength for coping with cohesive failure is improved, but lamination strength becomes insufficient
Solution Approach 1:
The invention uses homogeneous nylon 6 as the surface layer material and achieves lamination strength through controlled molecular orientation and crystallization rather than through blending with semi-aromatic polyamide. This homogeneous structure with optimized parameters provides both cohesive strength and lamination strength.
Solution Approach 2:
The invention changes the orientation factor and crystallization degree parameters of the nylon 6 surface layer to achieve optimal performance. This parameter optimization provides both cohesive strength and lamination strength without requiring the addition of semi-aromatic polyamide.
4Manufacturing precision
If stretching property is improved by adding polyamide resin with specific chemical structure, then thickness unevenness is decreased, but lamination strength is not sufficiently improved
Solution Approach 1:
The invention achieves improved lamination strength by controlling the orientation factor (0.25-0.35) and crystallization degree (15-30%) of the surface layer through heat fixation. These parameter changes directly enhance lamination strength without requiring specific chemical structure modifications or affecting thickness uniformity.
5Strength
If stratified silicate salt is added to improve strength for coping with prick, then mechanical strength is improved, but surface layer becomes susceptible to cleavage and lamination strength is insufficient
Solution Approach 1:
The invention achieves improved lamination strength by controlling the orientation factor (0.25-0.35) and crystallization degree (15-30%) of the surface layer. These parameter changes enhance both impact resistance and lamination strength without requiring silicate salt addition, preventing surface layer cleavage.
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 film exhibits excellent adhesive and lamination strength, maintains mechanical properties, and remains flexible even with excessive heat treatment, ensuring high impact resistance and suitable for various packaging applications.
Implementation Method 1
an orientation factor: 2Kz / (Kx + Ky) defined by the absorption coefficients of the MD direction Kx, the TD direction Ky, and the thickness direction Kz respectively of the bending vibration of the amide bond NH in the spectrum measured by FT-IR polarized ATR measurement
Implementation Method 2
adhesive property can be improved by increasing a heat fixation temperature to disrupt the orientation in the surface layer
Data Source
AI summary
The objective of the present invention is to provide a stretched polyamide film which is excellent in laminatability, lamination strength, mechanical properties and shock resistance property and which has effects to prevent goods being broken and protect a content from vibration and shock at the time of transportation when used as various packaging materials. The present invention relates to a stretched polyamide film, wherein a main constituent is nylon 6; at least one surface layer meets the following conditions (1) and (2); and the stretched polyamide film meets the following condition (3): (1) a relaxation degree of a surface layer orientation measured by IR spectroscopy is within a range of not less than 0.3 and not more than 0.5; (2) a crystallization degree of a surface layer measured by IR spectroscopy is within a range of not less than 1.0 and not more than 1.4; (3) a heat shrinkage rate (%) in TD direction at 160 °C for 10 minutes is within a range of not less than 0.6 and not more than 4.