Rubber latex compound, method for manufacturing glove, and glove

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Solution Overview

Problem

Existing rubber latex compounds used for manufacturing gloves require a high amount of acid-treated carbon black to achieve sufficient electrical conductivity, which leads to stiffness and reduced flexibility, compromising touch panel responsiveness.

Innovation Solution

A rubber latex compound is developed that includes carbon black, an anionic surfactant, a nonionic dispersant, and a water-soluble polymer, optimizing the DBP oil absorption and volatile content of the carbon black to enhance compound stability and electrical conductivity while minimizing the amount of carbon black needed.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a large amount of carbon black is added to achieve sufficient electrical conductivity, then the electrical conductivity is improved, but the flexibility of the glove deteriorates

Engineering Contradiction:
Improveelectrical conductivityVSAvoidflexibility
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent introduces acid-treated carbon black as an intermediary form that maintains electrical conductivity while reducing aggregation. The acid treatment modifies the surface properties of carbon black particles, enabling them to disperse more uniformly in the rubber latex matrix without requiring high addition amounts, thus maintaining glove flexibility while achieving sufficient conductivity

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the chemical parameters of carbon black through acid treatment, modifying its surface characteristics and reactivity. This parameter change allows carbon black to achieve better compound stability and dispersibility at lower addition levels (5-20 parts by mass), resolving the contradiction between achieving conductivity and maintaining flexibility

Inventive Principle:
Principle #35Parameter changes

2Reliability

If a large amount of carbon black is added to achieve low resistance, then the electrical conductivity is improved, but the workability of the glove deteriorates

Engineering Contradiction:
Improveelectrical conductivityVSAvoidworkability
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

Acid-treated carbon black serves as an intermediary that improves compound stability during the manufacturing process. The acid treatment creates surface groups that enhance interaction with rubber latex, preventing premature aggregation and gelation, thereby improving workability while achieving the required electrical conductivity at moderate carbon black levels

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If the amount of carbon black is increased to secure electrically conductive paths, then the electrical conductivity is improved, but the compound stability of carbon black deteriorates

Engineering Contradiction:
Improveelectrical conductivityVSAvoidcompound stability
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent applies acid treatment to change the chemical parameters of carbon black, introducing surface functional groups that enhance compatibility with rubber latex. This parameter modification improves compound stability by preventing aggregation and gelation, allowing adequate electrical conductivity to be achieved with carbon black addition of 5-20 parts by mass without compromising stability

Inventive Principle:
Principle #35Parameter changes

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 improved rubber latex compound enables the manufacturing of gloves with superior touch panel responsiveness and flexibility, achieving electrical conductivity with a smaller amount of carbon black addition.

Implementation Method 1

by adding an anionic surfactant, a nonionic dispersant, and a water-soluble polymer, each in an appropriate amount, the compound stability of the carbon black significantly improves, enabling improvement of the electrical conductivity of the coating film

Methodology Applied
Scientific EffectDispersion: Dispersion (of waves)

Implementation Method 2

by adding an anionic surfactant, a nonionic dispersant, and a water-soluble polymer, each in an appropriate amount, the compound stability of the carbon black significantly improves

Methodology Applied
Scientific EffectSurfactant action: Surfactant

Implementation Method 3

enabling improvement of the electrical conductivity of the coating film, whereby the present invention was accomplished

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentEP4105278B1Rubber latex compound, method for manufacturing glove, and glove
Publication Date: 2025.04.23 SHOWA GLOVE CO
  • EP4105278B1 patent drawingFigure 1
  • EP4105278B1 patent drawingFigure 2
  • EP4105278B1 patent drawingFigure 3

AI summary

An object of the prevent invention is to provide a rubber latex compound that enables manufacturing a glove which is superior in terms of touch panel responsiveness, and has superior flexibility. The rubber latex compound according to one aspect of the present invention is a rubber latex compound for a glove containing a rubber latex as a principal component, wherein carbon black, an anionic surfactant, a nonionic dispersant, and a water-soluble polymer are contained in the rubber latex compound; a DBP oil absorption of the carbon black is no less than 250 ml/100 g and no greater than 600 ml/100 g, and a volatile content of the carbon black is no less than 0.3% by mass and less than 1.0% by mass; an amount of addition of the water-soluble polymer with respect to 100 parts by mass of the carbon black is no less than 8 parts by mass and no greater than 50 parts by mass; and a total amount of addition of the nonionic dispersant and the water-soluble polymer with respect to 100 parts by mass of the carbon black is no less than 38 parts by mass and no greater than 200 parts by mass.