Peroxide Mixture for Fast EVA Crosslinking

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Solution Overview

Problem

The existing crosslinking processes for ethylene-vinyl acetate (EVA) copolymers are slow, leading to reduced productivity and often result in low crosslinking density, which affects the mechanical properties of finished products.

Innovation Solution

A peroxide mixture comprising O,O-tert-butyl-O-(2-ethylhexyl) monoperoxycarbonate and O,O-tert-amyl-O-2-ethylhexyl monoperoxycarbonate, with the latter present in a content ranging from 0.001% to 45% by weight, is used to accelerate the crosslinking reaction while maintaining a good crosslinking density.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional peroxide crosslinking processes are used for EVA copolymers, then the crosslinking reaction can proceed, but the crosslinking time is long resulting in reduced productivity

Engineering Contradiction:
Improvecrosslinking speedVSAvoidcrosslinking time
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The patent combines two different peroxides (di-tert-butyl percarbonate and di-tert-amyl percarbonate) into a mixture system. This combination creates a synergistic effect where the peroxide mixture achieves faster crosslinking rates compared to using a single peroxide compound, thereby reducing crosslinking time and improving productivity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent modifies the chemical parameters of the crosslinking system by introducing a specific mixture ratio of peroxides. By adjusting the composition parameters (ratio of di-tert-butyl percarbonate to di-tert-amyl percarbonate), the system achieves optimal crosslinking speed while maintaining adequate crosslinking density, thus resolving the time-productivity contradiction.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If crosslinking is accelerated to improve productivity, then crosslinking time is reduced, but crosslinking density decreases affecting mechanical properties

Engineering Contradiction:
Improvecrosslinking rateVSAvoidcrosslinking density
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The peroxide mixture combines the advantages of different peroxide compounds: di-tert-butyl percarbonate provides stable crosslinking while di-tert-amyl percarbonate enhances reaction speed. This merging of functional characteristics allows simultaneous achievement of high crosslinking density and fast crosslinking rate, resolving the contradiction between productivity and reliability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The invention creates a composite crosslinking system using a mixture of peroxide compounds rather than a single compound. This composite approach leverages the complementary properties of different peroxides to achieve both rapid crosslinking and high crosslinking density, ensuring that mechanical properties are maintained while productivity is improved.

Inventive Principle:
Principle #40Composite materials

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

This approach significantly increases the crosslinking reaction rate, resulting in faster production with improved mechanical properties such as higher breaking stress and modulus, thus enhancing productivity and dimensional stability of finished products.

Implementation Method 1

crosslinking ethylene-vinyl acetate (EVA) copolymers by placing these copolymers in the presence of free-radical-initiating peroxides

Methodology Applied
Scientific EffectFree-radical crosslinking: Chemical Bonding

Data Source

PatentUS8609781B2Mixture of peroxides for crosslinking elastomers
Publication Date: 2013.12.17 ARKEMA FRANCE SA

AI summary

The present invention relates to a mixture including at least O,O-tert-butyl-O-(2-ethylhexyl) monoperoxycarbonate and at least O,O-tert-amyl-O-2-ethylhexyl monoperoxycarbonate, where the O,O-tert-amyl-O-2-ethylhexyl monoperoxycarbonate is present in the mixture in an amount of from 0.001% to 45% by weight relative to the total weight of the mixture. The invention also relates to a crosslinkable composition that includes such a peroxide mixture and an elastomer; and to uses of the crosslinkable composition and mixture.