Aqueous Release Coating Composition for Tape Adhesive
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Solution Overview
Problem
Conventional release coating compositions for pressure sensitive adhesives often experience silicone migration into the adhesive layer, leading to decreased adhesive strength, particularly during storage.
Innovation Solution
An aqueous-based release coating composition comprising a vinyl-based emulsion copolymer with a copolymerizable acid monomer, a silicone-based emulsion with amine-, polyol-functional siloxane and epoxy-, glycol-functional siloxane, and a polymeric dispersant with an acid functional group, maintaining a weight ratio of silicone-based emulsion to polymeric dispersant between 2:1 to 3:1, which reduces silicone migration and provides low release force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional release coating compositions are used, then release force is achieved, but silicone migration into the adhesive layer occurs causing decreased adhesive strength
Solution Approach 1:
The patent introduces a release coating composition as an intermediary layer between the silicone-containing adhesive and the cover sheet. This coating acts as a barrier that prevents direct contact and migration of silicone into the adhesive, while still providing the necessary release function. The coating comprises specific polymers and release agents that create a controlled interface between the adhesive and cover sheet, eliminating the harmful silicone migration effect.
Solution Approach 2:
The release coating composition uses a composite formulation combining multiple components: polymers (such as polyvinyl acetate, ethylene vinyl acetate copolymer, or carboxymethyl cellulose), release agents (silicone oil, fluorinated oil, or wax), and optional additives. This composite material structure provides both the release function and the barrier property to prevent silicone migration, resolving the contradiction between achieving release force and maintaining adhesive strength.
2Ease of operation
If silicone-based release agents are used, then release function is provided, but silicone migration occurs during storage
Solution Approach 1:
The patent modifies the parameters of the release coating by carefully controlling the concentration and type of release agents, the molecular weight and structure of polymers, and the ratio of different components. By adjusting these parameters, the coating achieves optimal balance between providing release function and preventing silicone migration during storage. The specific parameter ranges mentioned in the patent (e.g., polymer molecular weight, release agent concentration) are optimized to resolve this contradiction.
Solution Approach 2:
The release coating composition exhibits local quality differences through its multi-component structure. Different regions or phases within the coating have different properties: the polymer matrix provides structural integrity and barrier function, while the release agents provide the release function. This localized functional distribution allows the coating to simultaneously achieve release capability and compositional stability during storage.
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 composition effectively minimizes silicone migration into the adhesive layer, maintaining adhesive strength and facilitating easy unwinding of tapes and release of cover sheets while ensuring low release force.
Implementation Method 1
anchoring effect by chemical and physical interaction among the vinyl-based emulsion copolymer comprising a copolymerizable acid monomer, the silicone-based emulsion having amino and epoxy functionality, and the dispersant comprising an acid functional group
Implementation Method 2
anchoring effect by chemical and physical interaction among the vinyl-based emulsion copolymer comprising a copolymerizable acid monomer, the silicone-based emulsion having amino and epoxy functionality, and the dispersant comprising an acid functional group
Implementation Method 3
provide for relatively-low release force at least in part because of the presence of siloxane
Data Source
AI summary
Aqueous-based release coating compositions are disclosed. The disclosed aqueous-based release coating compositions are particularly suitable for use with pressure sensitive adhesives. In some embodiments, the aqueous-based release coating compositions include (A) a vinyl-based emulsion copolymer comprising a copolymerizable acid monomer, (B) a silicone-based emulsion comprising a mixture of amine-, polyol-functional siloxane and epoxy-, glycol-functional siloxane, and (C) a polymeric dispersant comprising an acid functional group. In some embodiments, the weight ratio of silicone-based emulsion (B) to polymeric dispersant (C) in the aqueous-based release coating compositions is from 2:1 to 3:1. The disclosed release coating compositions are suitable for use in, inter alia, tape applications.