Method for preparing latex composition for dip-forming
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Solution Overview
Problem
The use of anionic emulsifiers in nitrile-based copolymer latex for glove manufacturing leads to excessive foam generation, pinholes, and degraded physical properties, such as stickiness and reduced mechanical stability, while also resulting in wastewater contamination.
Innovation Solution
A method for preparing a latex composition for dip forming by combining a monomer mixture of conjugated diene-based and ethylenically unsaturated nitrile monomers with an inorganic solvent, an ionic surfactant emulsifier, and starch, where the starch content is between 0.1 to 4.9 parts by weight, to enhance mechanical and polymerization stability, reducing the emulsifier content and minimizing foam generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If anionic emulsifier is used at 3 to 5 parts per hundred parts monomer in emulsion polymerization, then polymerization stability and particle size stability are improved, but excessive foam is generated causing pinholes and product quality degradation
Solution Approach 1:
The patent introduces a foam control agent as an intermediary substance to mediate between the emulsifier and the polymerization system. This agent specifically suppresses foam generation while allowing the emulsifier to maintain its stabilizing function, thus resolving the contradiction between polymerization stability and foam control
Solution Approach 2:
The patent optimizes the dosage of anionic emulsifier from the conventional 3-5 parts per hundred parts monomer to a reduced range of 1-3 parts, while simultaneously introducing a foam control agent. This parameter change allows maintaining polymerization stability with reduced foam generation
2Stability of the object's composition
If anionic emulsifier is used at 3 to 5 parts per hundred parts monomer in emulsion polymerization, then particle size stability and storage stability are improved, but a large amount of wastewater containing emulsifier is generated
Solution Approach 1:
The patent reduces the emulsifier dosage from 3-5 parts to 1-3 parts per hundred parts monomer, directly decreasing the amount of emulsifier that would end up in wastewater while maintaining storage stability through optimized formulation and the addition of foam control agent
3Reliability
If anionic emulsifier is used in nitrile-based copolymer latex, then polymerization stability is improved, but physical properties are degraded due to stickiness and slipping phenomenon
Solution Approach 1:
The patent optimizes the emulsifier concentration to 1-3 parts per hundred parts monomer (reduced from conventional 3-5 parts) and introduces a foam control agent, achieving polymerization stability while minimizing the negative impact on mechanical properties such as tensile strength and elongation
Solution Approach 2:
The patent creates a composite latex system combining nitrile-based copolymer with optimized emulsifier and foam control agent, where the synergistic interaction between components maintains polymerization stability while improving the mechanical properties and reducing stickiness
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 approach results in a latex composition with improved mechanical stability and polymerization stability, maintaining or enhancing tensile strength and elongation, while reducing emulsifier usage and wastewater generation, thus producing high-quality dip-formed articles like medical and industrial gloves.
Implementation Method 1
a content of the starch is 0.1 to 4.9 parts by weight with respect to 100 parts by weight of the monomer mixture
Implementation Method 2
introducing an additive including an inorganic solvent, an emulsifier and starch into the monomer mixture
Implementation Method 3
preparing a copolymer latex by polymerizing the monomer mixture
Data Source
AI summary
An exemplary embodiment provides a method for preparing a latex composition for dip forming, the method including: (a) preparing a monomer mixture including a conjugated diene-based monomer, an ethylenically unsaturated nitrile monomer and an ethylenically unsaturated acid monomer; (b) introducing an additive including an inorganic solvent, an emulsifier and starch into the monomer mixture; and (c) preparing a copolymer latex by polymerizing the monomer mixture, wherein a content of the starch is 0.1 to 4.9 parts by weight with respect to 100 parts by weight of the monomer mixture.