Adhesive Coating Blocking Prevention via Acrylate Cooling
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Solution Overview
Problem
The challenge is to produce adhesive-coated articles without the need for release papers or liners, allowing for high production speeds while preventing blocking of layers in rolls, as existing methods require time for crystallization of polyurethane polymers and incur costs from material and disposal expenses.
Innovation Solution
A method involving the application of a first polyurethane or polyurethane-polyurea polymer onto a substrate, followed by a mixture of a second polyurethane or polyurethane-polyurea polymer and an acrylate polymer, with cooling below the acrylate's glass transition temperature to prevent blocking, eliminating the need for release layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a crystalline polyurethane polymer is applied to a web and subsequently dried or cooled, then blocking of layers in a roll is prevented, but production speed is reduced due to the time required for crystallization
Solution Approach 1:
The invention changes the temperature parameter by maintaining the adhesive layer above its glass transition temperature, preventing crystallization and blocking while enabling high-speed production without waiting for crystallization to occur
Solution Approach 2:
Instead of allowing the polymer to crystallize to prevent blocking (conventional approach), the invention inverts the approach by keeping the polymer in a non-crystalline, rubbery state above its glass transition temperature, thereby preventing blocking through thermal energy rather than crystalline structure
2Reliability
If release paper is used to protect against blocking, then blocking prevention is achieved, but material costs and disposal costs increase
Solution Approach 1:
The invention extracts and eliminates the release paper component from the system by using the adhesive layer's own thermal properties (maintaining it above glass transition temperature) to prevent blocking, thereby removing the need for additional release paper materials and their associated costs
Solution Approach 2:
The adhesive layer serves its own blocking prevention function by maintaining itself in a non-blocking state through temperature control above the glass transition point, eliminating the need for external release paper protection
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
Enables rapid and economical coating and rolling of adhesive layers without blocking, even at elevated temperatures, without the use of release papers or liners, thereby enhancing production efficiency and reducing costs.
Implementation Method 1
cooling the article obtained to a temperature below the glass transition temperature of the acrylate polymer
Implementation Method 2
a crystalline polyurethane polymer is applied to a web and subsequently dried or cooled, a certain time will elapse before the adhesive polymer has crystallized sufficiently to prevent blocking
Data Source
AI summary
Method for the production of adhesive-coated articles, articles obtainable thereby and their use A method for the production of adhesive-coated articles comprises the steps of: (I) providing a substrate; (II) applying a first polyurethane and/or polyurethane-polyurea polymer onto the substrate, the first polyurethane and/or polyurethane-polyurea polymer being capable of attaining an at least partially crystalline state with a final degree of crystallinity and wherein during and/or after the application the first polyurethane and/or polyurethane-polyurea polymer is present in a non-crystalline state. The method further comprises the steps: (III) applying onto the first polyurethane and/or polyurethane-polyurea polymer of step (II) a composition comprising a mixture of a second polyurethane and/or polyurethane-polyurea polymer and furthermore an acrylate polymer, wherein the application is performed while the degree of crystallinity of the first polyurethane-polyurea polymer is lower than its final degree of crystallinity; and (IV) cooling the article obtained to a temperature below the glass transition temperature of the acrylate polymer.