Nitrile Rubber Glove Formulation for Natural Rubber Pliability
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Solution Overview
Problem
Nitrile rubber gloves lack the pliability and comfort of natural rubber latex gloves while maintaining the protective and non-allergenic properties, and existing methods to soften nitrile rubber often compromise strength or chemical resistance.
Innovation Solution
A nitrile butadiene rubber formulation with controlled crosslinking and thickness, using a blend of acrylonitrile, methacrylic acid, and butadiene components, and adjusting the levels of zinc oxide and other crosslinking agents to achieve force-strain characteristics similar to natural rubber latex without the need for stress relaxation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If nitrile rubber is used to make gloves, then chemical resistance and puncture resistance are improved, but pliability and ease to stretch deteriorate
Solution Approach 1:
The patent modifies the chemical composition parameters of nitrile rubber by incorporating specific plasticizers and softening agents in controlled amounts. This changes the material's physical properties to reduce stiffness while preserving chemical resistance, allowing the glove to stretch more easily without compromising protective properties
Solution Approach 2:
The patent creates a composite nitrile rubber formulation by combining base nitrile polymer with multiple additives including plasticizers, lubricants, and crosslinking agents in specific ratios. This composite structure maintains the chemical resistance of nitrile while introducing flexibility-enhancing components that improve pliability and ease of stretching
2Ease of operation
If nitrile rubber gloves are made thinner to improve comfort, then pliability is improved, but strength deteriorates
Solution Approach 1:
The patent optimizes the thickness parameter of the glove while compensating for strength loss through controlled addition of reinforcing agents and adjustment of crosslinking density. This allows thinner walls that improve comfort and flexibility while maintaining adequate tensile strength through material property modifications
Solution Approach 2:
The patent develops a composite formulation specifically designed for thin-glove applications, incorporating nano-sized reinforcing particles and optimized polymer blends that provide high strength-to-thickness ratio, enabling comfortable thin construction without sacrificing protective strength
3Strength
If crosslinking agents are increased to improve strength, then tensile strength is improved, but chemical resistance deteriorates
Solution Approach 1:
The patent precisely controls the concentration and type of crosslinking agents used in the nitrile rubber formulation. By optimizing crosslinking density within a specific range and selecting crosslinking agents with appropriate reactivity, the patent achieves sufficient tensile strength while preserving the chemical resistance properties of the nitrile polymer structure
Solution Approach 2:
The patent creates a balanced composite system where crosslinking agents are combined with chemical resistance-enhancing additives and polymer modifiers. This composite approach ensures that crosslinking provides necessary strength without creating pathways for chemical penetration, maintaining integrity against oils and solvents
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 resulting nitrile gloves are thinner, more pliable, and comfortable, with force-strain responses similar to natural rubber latex, maintaining sufficient strength and chemical resistance for industrial and medical applications.
Implementation Method 1
The first mechanism of crosslinking occurs by ionically bonding carboxylic acid groups together using multivalent metal ions. These ions are typically supplied through addition of zinc oxide to the emulsion.
Implementation Method 2
The other crosslinking mechanism is a covalent crosslinking of the butadiene segments of the polymer using sulfur and catalysts known as rubber accelerators.
Implementation Method 3
Gloves are often formed by first placing a coagulant solution, often calcium nitrate on ceramic glove moulds, then dipping into the nitrile latex to cause local gelation of nitrile rubber over the mould surface.
Data Source
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AI summary
An improved process and material for making elastomeric nitrile rubber articles is disclosed. In particular, the process and material formulation can produce nitrile rubber based articles, which exhibit force-strain characteristics that are comparable to those of natural rubber latex articles, while maintaining the tensile strength properties of nitrile rubber. The process includes an accelerator composition at the pre-cure stage having a dithiocarbamate, a thiazole, and a guanidine compound. The invention also includes an elastomeric nitrile rubber product made by the process, such as examination, surgical, or work gloves.