Methods of making compositions comprising thermoplastic and curable polymers and articles made from such methods
View Patent ↗Manufactured articles and methods of producing such articles are disclosed where the article has a thermoplastic polymer component and a curable polymer component. The curable polymer may be moisture-curable polymer, or microwave, dielectric or radio frequency curable polymer. The articles may be manufactured by a variety of polymer processing methods including extrusion, co-extrusion, co-molding, injection molding and calendering. A variety of articles and shapes may be made by the method including electric wire and cable, and weatherstripping.
1. A method of producing an article of manufacture comprising a thermoplastic polymer and a moisture-curable polymer, said method comprising introducing said thermoplastic polymer and said moisture-curable polymer separately into a die or mold wherein said polymers come into intimate contact, and curing said moisture-curable polymer by exposure to moisture wherein said cured moisture-curable polymer can not be further shaped by heat and wherein said moisture-curable polymer is co-extruded completely over and around said thermoplastic polymer.
2. A method of producing an article of manufacture comprising a thermoplastic polymer and a microwave, dielectric or radio frequency curable polymer comprising introducing said thermoplastic polymer and said microwave, dielectric or radio frequency curable polymer separately into a die or mold where said polymers come into intimate contact, and curing said microwave, dielectric or radio frequency curable polymer by exposure to microwave, dielectric or radio frequency energy, wherein the curable polymer is selected from the group consisting of RTV silicon compounds, styrenic homopolymers or copolymers, polyethylene, polyolefins comprising repeating units having from 3 to 20 carbon atoms: co-polymers of ethylene and a mono-unsaturated ester as well as terpolymers of these polymers, nitrile rubber, SBS, SBR, EP and EPR rubbers, and butyl rubber and wherein said microwave, dielectric or radio frequency curable polymer is co-extruded completely over and around said thermoplastic polymer.
3. The method according to claim 1 wherein said thermoplastic polymer includes a foaming agent.
4. The method according to claim 2 wherein said thermoplastic polymer includes a foaming agent.
5. The method according to any of claims 2 or 4 wherein said microwave, dielectric or radio frequency curable polymer includes a foaming agent.
6. The method according to any of claims 1 or 3 wherein said moisture-curable polymer includes a foaming agent.
7. The method according to claim 5 wherein the microwave, dielectric or radio frequency energy aids in the foaming due to the heat generated in the system by said microwave, dielectric or radio frequency energy that also cures the curable polymer.
8. The method according to claim 5 wherein the thermoplastic polymer is foamed and the microwave, dielectric or radio frequency energy aids in the foaming of the foaming agent in the thermoplastic polymer when excited by the microwave, dielectric or radio frequency energy.
9. The method according to claim 3 or claim 4 wherein the thermoplastic polymer is foamed by the foaming agent due to a change in pressure upon exiting the die.
10. The method according to claim 6 wherein the moisture-curable polymer is foamed by the foaming agent due to a change in pressure upon exiting the die.
11. The method according to any of claims 1 or 2 wherein the thermoplastic polymer is selected from the group consisting of polyolefins having 2 to 20 carbon atoms; EP, EPR or EPDM rubbers; styrene/butadiene polymers, copolymers or block copolymers; polypropylene or polypropylene copolymers; styrene homopolymers or copolymers; thermoplastic elastomers; nylon 6, nylon 6—6 or nylon 12, and polyester resins.
12. The method according to claim 1 wherein the moisture-curable polymer is selected from the group consisting of RTV silicon compounds; styrenic homopolymers or copolymers; polyethylene, polyolefins comprising repeating units having from 3 to 20 carbon atoms; co-polymers of ethylene and a mono-unsaturated ester as well as terpolymers of these polymers; nitrile rubber, EP, EPR and EPDM rubbers, and butyl rubber.
13. The method according to claim 2 wherein the microwave curable polymer, dielectric or radio frequency curable polymer is selected from the group consisting of co-polymers of ethylene and a mono- unsaturated ester, ethylene vinyl acetate and nitrile rubber.
14. The method according to claim 2 wherein the microwave, dielectric or radio frequency curable polymer further comprises from 0.1% up to about 50% by weight, based on the curable polymer, of an additive selected from the group consisting of carbon black, carbon soot, carbon fibrils, nanotubes, ethoxylated amines, a monoglycol ester of fatty acid, a diglycol ester of fatty acid, a polyglycol ester of a fatty acid, water and combinations of these polarizing materials, wherein the polarity of the additive causes heating by dielectric loss upon the application of microwave, dielectric or radio frequency energy.
15. The method according to claim 2 wherein the microwave, dielectric or radio frequency curable polymer further comprises a heat activated cure system selected from the group consisting of sulfur cure systems and organic peroxides.
16. The method according to claim 1 or claim 2 wherein migration of the curable polymer into the thermoplastic polymer causes interfacial cross links and improves the adhesion of the thermoplastic and curable polymers.
17. The method according to claim 2 wherein the microwave, dielectric or radio frequency curable polymer is cured by microwave energy in the frequency range of about 915 to about 2,415 MHz.
18. The method according to claim 2 wherein the microwave, dielectric or radio frequency curable polymer is cured by energy in the frequency range of less than about 900 MHz.
19. The method according to claim 1 or claim 2 wherein said article has a circular cross-sectional shape.
20. The method according to claim 1 or claim 2 wherein said article of manufacture is electrically conductive wire or cable.
21. A method of producing an article of manufacture comprising a thermoplastic polymer and a moisture-curable polymer, said method comprising introducing said thermoplastic polymer and said moisture-curable polymer separately into a die or mold wherein said polymers come into intimate contact, and curing said moisture-curable polymer by exposure to moisture wherein said cured moisture-curable polymer can not be further shaped by heat and wherein the moisture cure system is vinyl trimethoxy silane, organic peroxide and dibutyl tin dilaurate catalyst.