Water-Soluble Polymer Composition for Skin Patch Plaster Layer
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Solution Overview
Problem
Conventional methods for forming a plaster layer for skin patches using water-soluble polymers face challenges in controlling the curing speed, making it difficult to mix additives and apply the plaster evenly due to rapid gelation when polyvalent metal compounds and gelation rate retarding agents are used simultaneously.
Innovation Solution
A water-soluble polymer composition comprising poly(meth)acrylic acid or its salts, combined with a gelation rate retarding agent, allows for controlled gelation speed by adding the polyvalent metal compound as a cross-linking agent, enabling a desirable induction period for hardening and facilitating the mixing and application of the plaster layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a polyvalent metal compound and a gelation rate retarding agent are added simultaneously to a water-soluble polymer composition, then the curing speed can be controlled, but it becomes difficult to obtain a desirable curing speed and may hinder mixing and application operations
Solution Approach 1:
The invention divides the addition process into two separate stages: first adding the gelation rate retarding agent to the water-soluble polymer composition, then subsequently adding the polyvalent metal compound. This segmentation prevents simultaneous interaction that causes uncontrollable gelation, allowing adequate time for mixing and application operations while still achieving controlled curing speed.
Solution Approach 2:
The gelation rate retarding agent is added in advance to the water-soluble polymer composition before the polyvalent metal compound is introduced. This preliminary action prepares the system to control the subsequent gelation reaction, ensuring that when the crosslinking agent is added, the gelation proceeds at a manageable rate rather than occurring too rapidly.
2Strength
If the water-soluble polymer easily reacts with the polyvalent metal compound, then crosslinking efficiency is improved, but gelation proceeds during application making it difficult to apply to the support
Solution Approach 1:
The gelation rate retarding agent acts as an intermediary substance that moderates the reaction between the water-soluble polymer and the polyvalent metal compound. By introducing this intermediary first, the system becomes less reactive to the incoming crosslinking agent, preventing premature gelation during application while still allowing effective crosslinking to occur afterward.
Solution Approach 2:
The retarding agent is introduced in advance to modify the polymer composition's reactivity profile before the metal compound is added. This preliminary modification ensures that when application time comes, the mixture remains workable and does not gel too quickly, while the crosslinking efficiency is maintained through the subsequent controlled reaction.
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
This approach allows for uniform mixing of additives and easy application of the plaster layer, ensuring the desired properties of adhesiveness and elasticity in the skin patch, such as poultices or cooling sheets, by controlling the gelation speed effectively.
Implementation Method 1
when a polyvalent metal compound as a cross linking agent is added to a water-soluble polymer composition containing a gelation rate retarding agent together with poly(meth)acrylic acid or a salt thereof, and the resulting composition is used as a composition for forming a plaster layer of a skin patch, the gelation speed of the gel-like plaster can be easily controlled
Implementation Method 2
aluminum or a like polyvalent metal compound is added to the water-soluble polymer composition as a cross linking agent
Data Source
AI summary
The present invention relates to a water-soluble polymer composition which comprises a water-soluble poly(meth)acrylic polymer and a gelation rate retarding agent, and a composition for forming a plaster layer of a skin patch which is obtainable by adding a polyvalent metal compound to the water-soluble polymer composition. When a polyvalent metal compound is added, the aforesaid water-soluble polymer composition shows an appropriate induction period before the start of the hardening of the gel. When the water-soluble polymer composition is used for forming a plaster layer of a skin patch, therefore, additive ingredients can be uniformly mixed and the procedure for coating to a support can be facilitated.