Polyamide Film Primer Balancing Hot-Water Adhesion and Blocking
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Solution Overview
Problem
Conventional polyamide films suffer from issues such as blocking, reduced adhesion after hot water treatment, impaired printability, and transparency due to the use of lubricants, and inadequate blocking resistance during handling as rolls.
Innovation Solution
A polyamide film with a primer layer containing polyurethane resin A without silanol groups and polyurethane resin B with silanol groups, having different glass transition temperatures, is used to enhance adhesion, blocking resistance, and printability, with a specific blending ratio and manufacturing process that includes biaxial stretching and heat treatment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a curing agent is not contained in the primer layer to reduce volatile base components and improve safety, then water resistance and safety are improved, but blocking resistance deteriorates
Solution Approach 1:
The polyurethane resin with silanol groups performs self-crosslinking through condensation reaction, eliminating the need for external curing agents. This self-service mechanism achieves both water resistance and blocking resistance without adding separate curing agents that would increase volatile base components.
Solution Approach 2:
The invention changes the chemical composition parameter by introducing silanol groups into the polyurethane resin structure. This parameter change enables the resin to undergo condensation reaction and form crosslinked structures, simultaneously improving water resistance and blocking resistance without requiring additional curing agents.
2Object-affected harmful factors
If a lubricant is added to the primer layer to prevent blocking, then blocking resistance is improved, but haze increases and transparency is impaired
Solution Approach 1:
The polyurethane resin with silanol groups performs self-crosslinking through condensation reaction, eliminating the need for external curing agents. This self-service mechanism achieves both water resistance and blocking resistance without adding separate curing agents that would increase volatile base components.
Solution Approach 2:
The invention changes the chemical composition parameter by introducing silanol groups into the polyurethane resin structure. This parameter change enables the resin to undergo condensation reaction and form crosslinked structures, simultaneously improving water resistance and blocking resistance without requiring additional curing agents.
3Object-affected harmful factors
If polyurethane resin with silanol groups is used to improve blocking resistance, then blocking resistance is improved, but adhesion after hot water treatment deteriorates
Solution Approach 1:
The invention uses a composite primer layer containing both polyurethane resin with silanol groups and polyurethane resin without silanol groups. The silanol-containing resin provides blocking resistance through self-crosslinking, while the silanol-free resin maintains adhesion properties, creating a synergistic composite material that achieves both functions simultaneously.
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 maintains high adhesion and blocking resistance after hot water treatment, improves printability, and ensures transparency without the need for excessive lubricants, suitable for packaging and electrical insulation applications.
Implementation Method 1
it has been found that a primer layer containing a polyurethane resin having a silanol group and a polyurethane resin having no silanol group in a specific blending ratio enables a crosslinked structure to be formed by condensation reaction of the silanol group, thereby blocking resistance and water resistance can be exhibited
Implementation Method 2
a crosslinked structure to be formed by condensation reaction of the silanol group, thereby blocking resistance and water resistance can be exhibited
Implementation Method 3
Biaxially stretched polyamide films are widely used as packaging films for packaging food and other items because they have excellent mechanical properties, optical properties, thermal properties, and barrier properties
Implementation Method 4
a method of forming an easily adhesive coating film (hereinafter referred to as a 'primer layer') by applying a primer agent with adhesive activity to the base film
Data Source
Figure 1A~2
Figure 3
AI summary
[Problem to be solved] To provide a highly adhesive polyamide film that has high adhesion even after hot water treatment, while also having excellent blocking resistance, printability, transparency, etc. [Solution] A polyamide film having a primer layer formed on at least one side of a polyamide base film, characterized in that (1) the primer layer contains polyurethane resin A that does not have a silanol group and polyurethane resin B that has a silanol group, and (2) the polyurethane resin A and the polyurethane resin B have different glass transition temperatures (Tg).