Open cell foamed articles including silane-grafted polyolefin resins

• US 5,859,076 A
• Filed: 06/11/1997
• Issued: 01/12/1999
• Est. Priority Date: 11/15/1996
• Status: Expired due to Term

• Current Assignee: Sentinel Products Corporation
• Original Assignee: Sentinel Products Corporation
• Inventors: Hurley, Robert F., Bambara, John D., Kozma, Matthew L.
• Primary Examiner(s): Truong, Duc
• Application Number:
  US08/872,736
• Time in Patent Office: 580 Days
• Field of Search: 521/142, 521/79, 521/82, 521/50, 264/504, 264/45.2, 264/45.9, 525/64, 525/191, 525/197, 525/245, 525/290, 525/330.9, 525/331.9
• US Class Current: 521/79
• CPC Class Codes: C08F 210/02 Ethene
• CPC Class Codes: C08F 222/06 Maleic anhydride
• CPC Class Codes: C08F 230/085 the monomer being a polymerisable silane, e.g. (meth)acryloyloxy trialkoxy silanes or vinyl trialkoxysilanes
• CPC Class Codes: C08F 255/00 Macromolecular compounds obtained by polymerising monomers on to polymers of hydrocarbons as defined in group C08F10/00
• CPC Class Codes: C08F 255/02 on to polymers of olefins having two or three carbon atoms
• CPC Class Codes: C08F 255/08 on to polymers of olefins having four or more carbon atoms
• CPC Class Codes: C08F 8/00 Chemical modification by after-treatment graft polymers, block polymers, crosslinking with unsaturated monomers or with polymers C08F251/00 - C08F299/00; of conjugated diene rubbers C08C
• CPC Class Codes: C08J 2201/03 Extrusion of the foamable blend
• CPC Class Codes: C08J 2323/02 not modified by chemical after treatment
• CPC Class Codes: C08J 2323/16 Ethene-propene or ethene-propene-diene copolymers
• CPC Class Codes: C08J 2351/00 Characterised by the use of graft polymers in which the grafted component is obtained by reactions only involving carbon-to-carbon unsaturated bonds; Derivatives of such polymers
• CPC Class Codes: C08J 2423/00 Characterised by the use of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Derivatives of such polymers
• CPC Class Codes: C08J 2425/00 Characterised by the use of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an aromatic carbocyclic ring; Derivatives of such polymers
• CPC Class Codes: C08J 2451/00 Characterised by the use of graft polymers in which the grafted component is obtained by reactions only involving carbon-to-carbon unsaturated bonds; Derivatives of such polymers
• CPC Class Codes: C08J 9/0061 characterized by the use of several polymeric components
• CPC Class Codes: C08J 9/04 using blowing gases generated by a previously added blowing agent
• CPC Class Codes: C08J 9/103 Azodicarbonamide
• CPC Class Codes: C08L 2205/02 containing two or more polymers of the same C08L -group
• CPC Class Codes: C08L 2205/03 containing three or more polymers in a blend
• CPC Class Codes: C08L 2205/035 containing four or more polymers in a blend
• CPC Class Codes: C08L 23/04 : Homopolymers or copolymers of ethene
• CPC Class Codes: C08L 23/06 : Polyethene
• CPC Class Codes: C08L 23/08 : Copolymers of ethene C08L23/16 takes precedence
• CPC Class Codes: C08L 23/0815 : Copolymers of ethene with aliphatic 1-olefins
• CPC Class Codes: C08L 23/0853 : Vinylacetate
• CPC Class Codes: C08L 23/0869 : Acids or derivatives thereof
• CPC Class Codes: C08L 23/10 : Homopolymers or copolymers of propene
• CPC Class Codes: C08L 23/16 : Elastomeric ethene-propene or ethene-propene-diene copolymers, e.g. EPR and EPDM rubbers
• CPC Class Codes: C08L 23/28 : by reaction with halogens or compounds containing halogen C08L23/32 takes precedence
• CPC Class Codes: C08L 2312/00 : Crosslinking
• CPC Class Codes: C08L 2312/08 : by silane
• CPC Class Codes: C08L 2314/06 : Metallocene or single site catalysts
• CPC Class Codes: C08L 2666/02 : Organic macromolecular compounds, natural resins, waxes or and bituminous materials
• CPC Class Codes: C08L 2666/04 : Macromolecular compounds according to groups C08L7/00 - C08L49/00, or C08L55/00 - C08L57/00; Derivatives thereof
• CPC Class Codes: C08L 2666/06 : Homopolymers or copolymers of unsaturated hydrocarbons; Derivatives thereof
• CPC Class Codes: C08L 2666/24 : Graft or block copolymers according to groups C08L51/00, C08L53/00 or C08L55/02; Derivatives thereof
• CPC Class Codes: C08L 51/06 : grafted on to homopolymers or copolymers of aliphatic hydrocarbons containing only one carbon-to-carbon double bond
• CPC Class Codes: C08L 51/085 : on to polysiloxanes
• CPC Class Codes: C08L 83/00 : Compositions of macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon only; Compositions of derivatives of such polymers
• CPC Class Codes: C08L 83/04 : Polysiloxanes
• CPC Class Codes: C08L 91/00 : Compositions of oils, fats or waxes; Compositions of derivatives thereof

Abstract

Open cell foamed articles including silane-grafted single-site inititiated polyolefin resins are described. The single-site initiated olefin polymer resin can be a polyethylene, a copolymer of ethylene, a C3-C20 alpha-olefin, or a copolymer of ethylene, a C3-C20 alpha-olefin and a C4-C20 diene. The open cell foamed articles have good cushioning properties and can be non-allergenic.

Claims

1. An open cell foamed article comprising a silane-grafted single-site initiated polyolefin resin, wherein the foamed article has greater than 10 percent open cells and the single-site initiated polyolefin resin is a polyethylene, a copolymer of ethylene and a C3-C20 alpha-olefin, or a copolymer of ethylene, a C3-C20 alpha-olefin and a C4-C20 diene.

2. The open cell foamed article of claim 1, wherein the single-site initiated polyolefin resin has a density between about 0.83 and about 0.96 g cm^-3, a molecular weight distribution between about 1.5 and about 3.5, a melt index in the range of about 0.5 dg/min to about 100 dg/min, and a composition distribution breadth index greater than about 45 percent.

3. The open cell foamed article of claim 2, wherein the article includes greater than 5 weight percent of the single-site initiated polyolefin resin.

4. The open cell foamed article of claim 3, wherein the article includes greater than 40 weight percent of the single-site initiated polyolefin resin.

5. The open cell foamed article of claim 4, wherein the article includes greater than 75 weight percent of the single-site initiated polyolefin resin.

6. The open cell foamed article of claim 5, wherein the article includes greater than 90 weight percent of the single-site initiated polyolefin resin.

7. The open cell foamed article of claim 3, wherein the silane-grafted single-site initiated polyolefin resin has a silane-graft content of between about 0.001 and 4 percent.

8. The open cell foamed article of claim 7, wherein the silane-grafted single-site initiated polyolefin resin has a silane-graft content of between about 0.1 and 2 percent.

9. The open cell foamed article of claim 3, wherein the silane includes a vinyl silane having 2 or 3 hydrolyzable groups.

10. The open cell foamed article of claim 9, wherein the silane includes vinyl triethoxysilane.

11. The open cell foamed article of claim 3, comprising a partially cross-linked polyolefin blend including the single-site initiated polyolefin resin and a copolymer including ethylene and propylene, an ethylene-propylene-diene monomer terpolymer, an ethylene-vinyl acetate copolymer, an ethylene-maleic anhydride copolymer, an ethylene-ethyl acrylate copolymer, a polystyrene, a low density polyethylene, a linear low density polyethylene, a medium density polyethylene, a high density polyethylene, or a polypropylene.

12. The open cell foamed article of claim 11, wherein the polyolefin blend is partially silane-grafted.

13. The open cell foamed article of claim 1, wherein the foamed article has greater than 40 percent open cells.

14. The open cell foamed article of claim 13, wherein the foamed article has greater than 80 percent open cells.

15. The open cell foamed article of claim 3, wherein the silane further comprises an alkyl trialkoxy silane, where the alkyl is a C1 to C20 group and the alkoxy is a C1 to C10 group.

16. A method of making an open cell foamed article comprising the steps of:

providing a mixture including silane-grafted single-site initiated polyolefin resin and a foaming agent, wherein the single-site initiated polyolefin resin is a polyethylene, a copolymer of ethylene and a C3-C20 alpha-olefin, or a copolymer of ethylene, a C3-C20 alpha-olefin and a C4-C20 diene;

partially cross-linking the mixture; and

expanding the mixture to form an open cell foamed article having greater than 10 percent open cells.

17. The method of claim 16, wherein the step of expanding the mixture comprises continuous extrusion of the mixture.

18. The method of claim 16, wherein the step of expanding the mixture comprises free expansion of the mixture.

19. The method of claim 16, wherein the step of expanding the mixture comprises compression molding the mixture at increased temperature and pressure.

20. The method of claim 19, wherein compression molding comprises the steps of pressing the polymer mixture using a high tonnage press at a temperature of between 240°

and 480°

F. and a pressure of between 50 and 5000 psi for between 20 and 90 minutes followed by heating the polymer mixture at a temperature between 300° and

380°

F.

21. The method of claim 20, wherein compression molding comprises the steps of pressing the polymer mixture using a high tonnage press at a temperature of between 275°

and 320°

F. and a pressure of between 250 and 2500 psi for between 20 and 90 minutes followed by heating the polymer mixture at a temperature between 300° and

380°

F.

22. The method of claim 16, wherein the step of cross-linking the polymer blend includes hydrolyzing the silane.

23. The method of claim 16, further comprising the step of crushing the foamed article after the expanding step.

24. The method of claim 23, wherein the foamed article has greater than 50 percent open cells after the crushing step.

25. The method of claim 24, wherein the foamed article has greater than 80 percent open cells after the crushing step.

26. The method of claim 23, further comprising the step of pinning the foamed article.

27. The method of claim 16, wherein the step of cross-linking the polymer blend further includes cross-linking with a peroxide.

28. The method of claim 16, wherein the mixture includes a partially cross-linked polyolefin blend including the single-site initiated polyolefin resin and a copolymer including ethylene and propylene, an ethylene-propylene-diene monomer terpolymer, an ethylene-vinyl acetate copolymer, an ethylene-maleic anhydride copolymer, an ethylene-ethyl acrylate copolymer, a low density polyethylene, a linear low density polyethylene, a medium density polyethylene, a high density polyethylene, or a polypropylene.

29. The method of claim 28, further comprising the step of grafting the polyolefin blend with a silane.

30. The method of claim 16, wherein the mixture includes an alkyl trialkoxy silane, where the alkyl is a C1 to C20 group and the alkoxy is a C1 to C10 group.