Scorch retarding crosslinking compositions comprising a hydroquinone, a sulfur accelerator, a coagent and a free radical initiator
First Claim
1. An improved composition for inclusion during and for retarding scorch during the compounding of thermoplastic polymers, curable with organic peroxides, elastomeric polymers, curable with organic peroxides, and mixtures of thermoplastic and elastomeric polymers, curable with organic peroxides, in the presence of free radical curing agents selected from the group organic peroxides to produce compounded polymers and for subsequent free radical cure of said compounded polymers by decomposition of the free radical curing agent in said compounded polymer which improved composition is prepared by mixing as the essential ingredients:
- a) sulfur accelerator selected from the group dithiocarbamates, thiurams, thiazoles, sulfenamides, thioureas, and xanthates;
b) hydroquinone in a weight ratio of 1;
50 to 500;
1 to sulfur accelerator;
c) free radical initiator selected from the group consisting of organic peroxides in a weight ratio of 2;
1 to 100;
0.5 to the total amount of sulfur accelerator and hydroquinone; and
d) coagent selected from the group consisting of polyfunctional vinyl monomers, polyfunctional allyl monomers, mixtures of monofunctional vinyl monomers with polyfunctional vinyl monomers, mixtures of monofunctional vinyl monomers with polyfunctional allyl monomers, mixtures of monofunctional allyl monomers with polyfunctional vinyl monomers and mixtures of monofunctional allyl monomers with polyfunctional allyl monomers in a weight ratio of 100;
1 to 1;
100 by weight based on total weight of hydroquinone and sulfur accelerator.
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Accused Products
Abstract
A crosslinkable composition of a polymeric thermoplastic and/or elastomeric material which is susceptible to scorching when processed at elevated temperatures, prior to crosslinking, in the presence of a free radical initiator, is protected against such scorching by the incorporation therein of a mixture of at least one hydroquinone compound and a sulfur accelerator. This mixture may also contain at least one monomeric allylic, methacrylic, acrylic or diene type coagent. The mixture exhibits a synergistic effect resulting in improved scorch protection for peroxide cured systems when compared with the protection afforded by the components singly.
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Citations
22 Claims
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1. An improved composition for inclusion during and for retarding scorch during the compounding of thermoplastic polymers, curable with organic peroxides, elastomeric polymers, curable with organic peroxides, and mixtures of thermoplastic and elastomeric polymers, curable with organic peroxides, in the presence of free radical curing agents selected from the group organic peroxides to produce compounded polymers and for subsequent free radical cure of said compounded polymers by decomposition of the free radical curing agent in said compounded polymer which improved composition is prepared by mixing as the essential ingredients:
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a) sulfur accelerator selected from the group dithiocarbamates, thiurams, thiazoles, sulfenamides, thioureas, and xanthates; b) hydroquinone in a weight ratio of 1;
50 to 500;
1 to sulfur accelerator;c) free radical initiator selected from the group consisting of organic peroxides in a weight ratio of 2;
1 to 100;
0.5 to the total amount of sulfur accelerator and hydroquinone; andd) coagent selected from the group consisting of polyfunctional vinyl monomers, polyfunctional allyl monomers, mixtures of monofunctional vinyl monomers with polyfunctional vinyl monomers, mixtures of monofunctional vinyl monomers with polyfunctional allyl monomers, mixtures of monofunctional allyl monomers with polyfunctional vinyl monomers and mixtures of monofunctional allyl monomers with polyfunctional allyl monomers in a weight ratio of 100;
1 to 1;
100 by weight based on total weight of hydroquinone and sulfur accelerator. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
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Specification