Coating Agent Composition for Vulcanized Rubber

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Solution Overview

Problem

Existing coating agent compositions for vulcanized rubber-molded products fail to simultaneously satisfy bleeding evaluation, flexibility evaluation by bending test, and adhesion reduction due to bloom from high-temperature and high-humidity tests while maintaining adequate adhesion to vulcanized rubber.

Innovation Solution

A coating agent composition comprising a polytetrafluoroethylene resin emulsion, an urethane resin emulsion, and a hydrogenated NBR emulsion, with optional additions of an acrylic resin emulsion and ethylene-vinyl acetate copolymer resin emulsion, optimized in terms of weight ratios and molecular weights to enhance flexibility, adhesion, and prevent bloom.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If an urethane resin emulsion is used as a coating agent for vulcanized rubber-molded products, then adhesion to vulcanized rubber is satisfactory, but adhesion reduction due to bloom from high-temperature and high-humidity tests shows unsatisfactory results

Engineering Contradiction:
Improveadhesion to vulcanized rubberVSAvoidadhesion stability under high-temperature and high-humidity conditions
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent combines multiple resin emulsions (urethane resin emulsion, acrylic resin emulsion, and hydrogenated NBR emulsion) to create a composite coating agent. This composite formulation leverages the adhesion properties of urethane resin while incorporating acrylic and hydrogenated NBR resins that provide resistance to bloom under high-temperature and high-humidity conditions, thereby resolving the contradiction between initial adhesion strength and long-term adhesion stability.

Inventive Principle:
Principle #40Composite materials

2Strength

If coating agent compositions from Patent Documents 2 and 3 are used, then adhesion to vulcanized rubber shows superior results, but bleeding evaluation, flexibility evaluation by bending test, and adhesion reduction due to bloom show inferior results

Engineering Contradiction:
Improveadhesion to vulcanized rubberVSAvoidperformance across multiple evaluation criteria
Core Design Contradiction:
StrengthVSAdaptability or versatility

Solution Approach 1:

The patent employs a multi-component resin emulsion system where each component contributes specific properties: urethane resin for adhesion, acrylic resin for flexibility and bleeding resistance, and hydrogenated NBR resin for overall coating performance. This composite approach enables the coating agent to simultaneously satisfy adhesion requirements and maintain flexibility, bleeding resistance, and stability under high-temperature and high-humidity conditions.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent optimizes the composition by assigning specific functional roles to different resin components based on their inherent properties. The urethane resin specifically targets adhesion to vulcanized rubber, while the acrylic and hydrogenated NBR resins address flexibility, bleeding resistance, and environmental stability. This functional differentiation within the composite system allows each component to excel at its specific function while contributing to overall performance.

Inventive Principle:
Principle #3Local quality

3Strength

If a coating agent composition is optimized for adhesion, then adhesion test results improve, but bleeding evaluation, flexibility by bending test, and adhesion reduction due to bloom deteriorate

Engineering Contradiction:
Improveadhesion to vulcanized rubberVSAvoidcoating composition stability under various test conditions
Core Design Contradiction:
StrengthVSStability of the object's composition

Solution Approach 1:

The patent creates a balanced composite coating agent where the urethane resin emulsion provides adhesion while acrylic resin emulsion and hydrogenated NBR emulsion provide compositional stability. The specific formulation ratios and component selection ensure that the coating maintains its integrity under bleeding tests, bending tests, and high-temperature high-humidity exposure, preventing the trade-off between adhesion strength and compositional stability.

Inventive Principle:
Principle #40Composite materials

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 satisfies bleeding evaluation, flexibility, and adhesion reduction due to bloom in high-temperature and high-humidity tests without impairing adhesion to vulcanized rubber, suitable for various rubber products including seals, rolls, and hoses, offering low friction and abrasion resistance.

Implementation Method 1

evaluation of adhesion to vulcanized rubber by an adhesion test

Methodology Applied
Scientific EffectAdhesion: Adhesive

Implementation Method 2

comprising (A) a polytetrafluoroethylene resin emulsion, (B) an urethane resin emulsion, and (C) a hydrogenated NBR emulsion

Methodology Applied
Scientific EffectEmulsion: Emulsion

Implementation Method 3

evaluation of adhesion to vulcanized rubber due to bloom from the rubber by a high-temperature and high-humidity test

Methodology Applied
Scientific EffectBloom prevention:

Implementation Method 4

bleeding evaluation (70°C, 30 days)

Methodology Applied
Scientific EffectBleeding resistance:

Implementation Method 5

evaluation of the flexibility of the coating agent by a bending test

Methodology Applied
Scientific EffectThermal stability:

Implementation Method 6

evaluation of adhesion to vulcanized rubber due to bloom from the rubber by a high-temperature and high-humidity test

Methodology Applied
Scientific EffectHumidity resistance:

Implementation Method 7

offering low friction and abrasion resistance

Methodology Applied
Scientific EffectFriction reduction: Lubrication

Implementation Method 8

offering low friction and abrasion resistance

Methodology Applied
Scientific EffectAbrasion resistance: Wear

Data Source

PatentEP2902457B1Coating agent composition
Publication Date: 2018.11.14 NOK CORP

AI summary

Disclosed is a coating agent composition comprising (A) a polytetrafluoroethylene resin emulsion, (B) an urethane resin emulsion, and (C) a hydrogenated NBR emulsion, and preferably further comprising (D) an acrylic resin emulsion and/or an ethylene-vinyl acetate copolymer resin emulsion. When this coating agent composition is used as a surface coating agent for general vulcanized rubber-molded products, evaluation of adhesion to rubber by an adhesion test is hardly impaired, and bleeding evaluation, evaluation of the flexibility of the coating agent by a bending test, and evaluation of the reduction in adhesion to rubber due to bloom from the rubber by a high-temperature and high-humidity test are all satisfied.