Acrylic Copolymer Pressure-Sensitive Adhesive for Skin Patches
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Solution Overview
Problem
Conventional transdermal absorption preparations face challenges in achieving a balance between pressure-sensitive adhesiveness and cohesive force, often resulting in glue residue and skin irritation due to the use of softeners and plasticizers, which compromise the adhesive properties and drug stability.
Innovation Solution
A composition comprising an acrylic copolymer with hydroxyethyl (meth)acrylate, a pseudo-crosslinking compound, and a plasticizer, where the ratio of plasticizer to pseudo-crosslinking compound ranges from 30:1 to 250:1, providing a balanced pressure-sensitive adhesive property and cohesive force, and including alkyl (meth)acrylate and N-vinyl-2-pyrrolidone to enhance adhesive properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a large amount of softener or plasticizer is added to improve drug release, then cohesive force becomes insufficient and glue residue occurs, but pressure-sensitive adhesiveness is compromised
Solution Approach 1:
The patent changes the chemical composition parameters of the pressure-sensitive adhesive agent by incorporating specific functional groups (carboxyl, hydroxyl, amino groups) and controlling the molecular weight distribution. This allows the adhesive to maintain appropriate cohesive force while enabling sufficient drug release without requiring excessive plasticizers that would cause glue residue.
Solution Approach 2:
The patent creates a composite pressure-sensitive adhesive system by combining acrylic polymer base resins with specific functional monomers and additives. This composite structure provides both the necessary cohesive strength and the controlled drug release properties, eliminating the need to sacrifice cohesive force for drug release enhancement.
2Strength
If crosslinking methods are applied to improve cohesive force and remove glue residue, then cohesive force is improved but pressure-sensitive adhesive property is lowered due to hardening
Solution Approach 1:
The patent carefully controls the crosslinking degree by selecting appropriate crosslinking agents and ratios, and by controlling the molecular weight of the base resin. This parameter optimization ensures that crosslinking provides sufficient cohesive force without creating excessive hardness that would deteriorate pressure-sensitive adhesive properties and skin follow-up characteristics.
3Object-generated harmful factors
If conventional crosslinking methods are used to secure cohesive force, then glue residue is removed but skin sticking property or follow-up property becomes insufficient
Solution Approach 1:
The patent optimizes the molecular weight of the acrylic polymer (specifically controlling it to be 100,000-500,000) and the crosslinking density to achieve the right balance. This parameter control ensures that the adhesive has enough cohesive force to prevent glue residue while maintaining the softness and flexibility needed for good skin follow-up properties.
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 solution achieves excellent pressure-sensitive adhesiveness, prevents glue residue, and reduces skin irritation, while maintaining a high cohesive force, allowing for easy peeling without causing skin irritation or hair plucking, and ensuring the adhesive properties are preserved without hardening.
Implementation Method 1
an acrylic copolymer which makes a specific amount of hydroxyethyl (meth)acrylate as a constituent
Implementation Method 2
a method to micro crosslink the pressure-sensitive adhesive agent itself by a crosslinking agent
Implementation Method 3
a method to let a large amount of a plasticizer be contained
Data Source
AI summary
It is intended to provide a composition which has well-balanced pressure-sensitive adhesiveness and cohesive force as well as favorable application properties to the skin, and a patch which has the above-described characteristics and hardly peels off. This object can be achieved by providing a composition comprising an acrylic copolymer containing from 3 to 25% by weight of hydroxyethyl (meth)acrylate as a constituent, a plasticizer and a pseudo-crosslinking compound, wherein the ratio of the content of the plasticizer to the content of the pseudo-crosslinking compound ranges from 30:1 to 250:1, and a patch.