Latex Composition for Protective Gloves

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Solution Overview

Problem

Existing protective gloves suffer from a surface rubber layer that easily wears out with repeated use, leading to cracks and poor flexibility, despite attempts to improve wear resistance by forming thick rubber layers.

Innovation Solution

A latex composition comprising two diene rubber latices: one with a high molecular weight and one with a low molecular weight, both containing ethylenically unsaturated acid monomer units, are combined to form a rubber layer on a fiber substrate, optimizing the weight ratio and molecular weights to achieve flexibility and wear resistance while minimizing cracks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a thick rubber layer is formed to improve wear resistance, then wear resistance is improved, but the glove is likely to have cracks and has poor flexibility

Engineering Contradiction:
Improvewear resistanceVSAvoidflexibility
Core Design Contradiction:
StrengthVSEase of operation

Solution Approach 1:

The patent applies parameter changes by controlling the molecular weight distribution of diene rubber in the latex composition. Specifically, it uses diene rubber with a weight average molecular weight of 100,000 to 5,000,000 and a number average molecular weight of 10,000 to 500,000, creating a broad molecular weight distribution that optimizes both wear resistance and flexibility without requiring a thick rubber layer.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite material system by combining diene rubber with specific molecular weight characteristics with acid group-containing diene rubber. This composite approach allows the rubber layer to achieve both high wear resistance and good flexibility through the synergistic effects of different rubber components with complementary properties.

Inventive Principle:
Principle #40Composite materials

2Strength

If a thick rubber layer is formed to improve wear resistance, then wear resistance is improved, but cracks appear on the surface

Engineering Contradiction:
Improvewear resistanceVSAvoidcrack resistance
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent changes the molecular weight parameters of the diene rubber to resolve the contradiction between wear resistance and crack resistance. By specifying a weight average molecular weight of 100,000 to 5,000,000 and number average molecular weight of 10,000 to 500,000, the rubber layer achieves sufficient strength for wear resistance while the broad molecular weight distribution prevents stress concentration that leads to cracking.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies beforehand cushioning by using acid group-containing diene rubber with specific molecular weight characteristics that anticipates and prevents crack formation. The acid groups provide crosslinking sites that create a more uniform and resilient rubber matrix, cushioning against the development of cracks under repeated stress and wear conditions.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

Data Source

PatentEP3739000B1Latex composition
Publication Date: 2023.11.01 ZEON CORP
  • EP3739000B1 patent drawingFigure 1(A)~1(B)
  • EP3739000B1 patent drawing

AI summary

The present invention provides a latex composition comprising a latex (A) of a diene rubber (a) having a weight average molecular weight of 50,000 or more and 1,000,000 or less and containing an ethylenically unsaturated acid monomer unit; and a latex (B) of a diene rubber (b) having a weight average molecular weight of 500 or more and less than 50,000 and containing an ethylenically unsaturated acid monomer unit.