Nitrile Copolymer Latex Composition for Stronger, Softer Dip-Molded Gloves
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Solution Overview
Problem
Existing nitrile-based rubber gloves face issues with low tensile strength, high modulus at 300%, and poor workability during manufacturing, leading to defects such as syneresis and latex-flowing shapes, which affect the quality and durability of the final product.
Innovation Solution
A carboxylic acid-modified nitrile-based copolymer latex composition is developed, incorporating carboxyalkyl (meth)acrylate and ethylenic unsaturated sulfonic acid monomer-derived repeating units, enhancing binding with zinc oxide to improve tensile strength and workability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the film formation speed is increased to improve productivity, then productivity is improved, but workability deteriorates due to increased syneresis
Solution Approach 1:
The patent modifies the chemical composition parameters of the latex by incorporating carboxyalkyl (meth)acrylate monomer and ethylenic unsaturated sulfonic acid monomer in specific ratios. This changes the physical and chemical properties of the latex, allowing faster film formation without excessive syneresis. The specific parameter range (0.1-10 wt% carboxyalkyl (meth)acrylate, 0.1-5 wt% ethylenic unsaturated sulfonic acid) optimizes both productivity and workability
Solution Approach 2:
The patent creates a composite latex system by combining nitrile-based copolymer with specific functional monomers (carboxyalkyl (meth)acrylate and ethylenic unsaturated sulfonic acid). This composite structure provides both fast film formation capability and controlled syneresis, resolving the contradiction between productivity and workability
2Strength
If ionic bonds are increased to improve tensile strength, then tensile strength is improved, but modulus at 300% increases reducing wearing sensation
Solution Approach 1:
The patent carefully controls the ionic bond formation by limiting carboxylic acid content to specific ranges (0.1-10 wt% carboxyalkyl (meth)acrylate) and adjusting pH to 7-12. This parameter optimization ensures sufficient tensile strength through ionic bonding while maintaining low modulus at 300% for comfort. The balanced composition prevents excessive crosslinking that would increase modulus
3Productivity
If syneresis speed is increased to improve film formation efficiency, then film formation efficiency is improved, but latex stability is reduced causing agglomerate formation
Solution Approach 1:
The ethylenic unsaturated sulfonic acid monomer acts as an intermediary component that mediates between film formation speed and latex stability. The sulfonic acid groups provide controlled syneresis while the specific molecular structure prevents excessive particle aggregation. This intermediary substance enables efficient film formation while maintaining colloidal stability
Solution Approach 2:
The patent optimizes the concentration of syneresis-promoting components within specific ranges (0.1-5 wt% ethylenic unsaturated sulfonic acid) and controls pH (7-12) to achieve the right balance. These parameter changes ensure syneresis occurs at an optimal rate that maintains both productivity and latex stability, preventing agglomerate formation
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 results in gloves with improved tensile strength, reduced modulus at 300%, and enhanced wearing sensation while maintaining excellent workability, addressing the manufacturing challenges of nitrile-based rubber gloves.
Implementation Method 1
an ionic bond occurring between a methacrylic acid which is one of the monomers used in the preparation of the latex for dip molding and zinc ions of zinc oxide added to a latex composition for dip molding
Data Source
AI summary
Provided is a carboxylic acid-modified nitrile-based copolymer latex composition, and more particularly, a carboxylic acid-modified nitrile-based copolymer latex composition including a carboxylic acid-modified nitrile-based copolymer. The carboxylic acid-modified nitrile-based copolymer includes a carboxyalkyl (meth)acrylate monomer-derived repeating unit and a repeating unit derived from an ethylenic unsaturated sulfonic acid monomer including a sulfonate salt or a sulfonate ester. A latex composition for dip molding including the same, and a molded article therefrom are also provided.