Process for the production of silane-crosslinked polyolefin in the presence of non-tin catalyst and resulting crosslinked polyolefin

Patent metadata

Field	Value
Publication number	US-9790307-B2
Application number	US-201414569057-A
Country	US
Kind code	B2
Filing date	Dec 12, 2014
Priority date	Dec 13, 2013
Publication date	Oct 17, 2017
Grant date	Oct 17, 2017

Abstract

A process for producing a silane-crosslinked polyolefin which comprises exposing a polyolefin containing at least one [1,3,2]-dioxasilinane ring structure to moisture in the presence of an organic carboxylic acid, which is used as a hydrolysis and condensation catalyst and does not contain tin, thereby producing the silane-crosslinked polyolefin, wherein the polyolefin containing at least one [1,3,2]-dioxasilinane ring structure is made by the process of grafting an olefinically unsaturated [1,3,2]-dioxasilinane to a polyolefin in the presence of a free radical initiator. There is also provided the resulting silane-crosslinked polyolefin and the graftable silane composition used in the process.

First claim

What is claimed is:

1. A process for producing a silane-crosslinked polyolefin which comprises exposing a polyolefin containing at least one [1,3,2]-dioxasilinane ring structure to moisture in the presence of an organic carboxylic acid used as hydrolysis and condensation catalyst which does not contain tin, thereby producing the silane-crosslinked polyolefin, wherein the polyolefin contains at least one [1,3,2]-dioxasilinane ring structure and is made by the process of grafting an olefinically unsaturated [1,3,2]-dioxasilinane to a polyolefin in the presence of a free radical initiator, wherein the olefinically unsaturated [1,3,2]-dioxasilinane is given by general Formula (I):

where R 1 is a straight chain or branched alkyl group of from 1 to 6 carbon atoms or hydrogen;
R 2 is a straight chain or branched alkyl group of from 1 to 6 carbon atoms or a cycloalkyl group of from 5 to 8 carbon atoms;
each occurrence of R 3 is hydrogen;
X 1 is

wherein R 1 is a straight chain or branched alkyl group of from 1 to 6 carbon atoms or hydrogen, R 2 is a straight chain or branched alkyl group of from 1 to 6 carbon atoms or a cycloalkyl group of from 5 to 8 carbon atoms, and each occurrence of R 3 is hydrogen and the organic carboxylic acid is at least one organic carboxylic acid having general Formula (III):

wherein G is a monovalent or polyvalent hydrocarbon containing up to 28 carbon atoms selected from the group consisting of alkyl, cycloalkyl, alkenyl, cycloalkenyl, aryl, aralkyl and arenyl; and the subscripts a and b are independently integers wherein a is 0 or 1 and b is 1 to 3.

2. The process of claim 1 wherein the polyolefin is polyethylene or a copolymer of ethylene and an alpha-olefin of 3 to 20 carbon atoms.

3. The process of claim 1 wherein the polyolefin is at least one member selected from the group consisting of homopolymers, copolymers, terpolymers, and tetrapolymers of ethylene, propylene, butene, pentene, hexene, heptene, octene, nonene, decene, dienes, cyclic dienes and aromatic dienes.

4. The process of claim 1 where the organic carboxylic acid, which is used as a hydrolysis and condensation catalyst and does not contain tin, is selected from the group consisting of 2,2-dimethylhexanoic acid, 2-ethyl-2,5-dimethylhexanoic acid, 2,2-dimethyloctanoic acid, and 2-ethyl-2,11-dimethyldodecanoic acid, lauric acid, capric acid, myristic acid, palmitic acid, oleic acid, stearic acid, behenic acid, arachidic acid, 12-hydroxystearic acid, ricinolic acid, montanic acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelic acid, sebacic acid, phthalic acid and combinations thereof.

5. The process of claim 1 wherein the organic carboxylic acid, which is used as a hydrolysis and condensation catalyst and does not contain tin, is at least one organic carboxylic acid having the general Formula (III):

wherein G is a monovalent hydrocarbon group having from 6 to 18 carbon atoms and has the Formula (V):

wherein each of R 4 , R 5 and R 6 is independently an alkyl group having from 1 to 15 carbon atoms with the proviso that the sum of carbon atoms in R 4 , R 5 and R 6 groups is from 5 to 17 carbon atoms, a is 0 and b is 1.

6. The process of claim 5 wherein the organic carboxylic acid is selected from the group consisting of 2,2-dimethylhexanoic acid, 2-ethyl-2,5-dimethylhexanoic acid, 2,2-dimethyloctanoic acid, 2-ethyl-2,11-dimethyldodecanoic acid and combinations thereof.

7. The process of claim 1 wherein the amount of [1,3,2]-dioxasilinane ring structure moieties in the total grafting reaction mixture is greater than about 5 mole percent based on the moles of silicon atoms in the total grafting reaction mixture.

8. The process of claim 1 wherein the grafting of olefinically unsaturated [1,3,2]-dioxasilinane to a polyolefin is conducted in the presence of a free-radical initiator wherein the free-radical initiator is selected from the group consisting of organic peroxides, organic peresters, azo compounds and combinations thereof.

9. The process of claim 1 further comprising:
a) combining under anhydrous conditions:
(i) polyolefin,
(ii) olefinically unsaturated [1,3,2]-dioxasilinane,
(iii) a free radical initiator,
(iv) organic carboxylic acid used as a hydrolysis and condensation catalyst for the crosslinking reaction of the resultant crosslinkable polyolefin containing at least one [1,3,2]-dioxasilinane ring structure when crosslinkable polyolefin containing at least one [1,3,2]-dioxasilinane ring structure is exposed to moisture, and
(v) an anti-oxidant for stabilizing the free radical initiator

b) heating the combination resulting from step (a) at a temperature above the crystalline melting point of polyolefin (i) to graft silane (ii) to polyolefin (i); and,
c) exposing the product resulting from step (b) to moisture to effect hydrolysis and condensation of polyolefin containing at least one [1,3,2]-dioxasilinane ring structure, thereby providing silane-crosslinked polyolefin, wherein the olefinically unsaturated[1,3,2]-dioxasilinane (ii), a free radical initiator (iii), an organic carboxylic acid (iv) and anti-oxidant (vi) are mixed to form a graftable silane composition prior to combining with the polyolefin in step (a).

10. The process of claim 9 , wherein the graftable silane composition comprises from 70 to 99.79 weight percent of an olefinically unsaturated[1,3,2]-dioxasilinane (ii), from 0.1 to 10 weight percent of a free radical initiator (iii), from 0.1 to 10 weight percent of a percent organic carboxylic acid (iv) and from 0.01 to 10 weight percent of a percent anti-oxidant (vi), said weight percents based on the sum of the weights of olefinically unsaturated[1,3,2]-dioxasilinane (ii), free radical initiator (iii), organic carboxylic acid (iv) and anti-oxidant (vi).

11. The process of claim 10 , wherein the organic carboxylic acid (iv) has the general Formula (III):

wherein G is a monovalent hydrocarbon group having from 6 to 18 carbon atoms and having the Formula (V):

wherein each R 4 , R 5 and R 6 is independently an alkyl group having from 1 to 15 carbon atoms with the proviso that the sum of carbon atoms in R 4 , R 5 and R 6 groups is from 5 to 17 carbon atoms, a is 0 and b is 1.

12. The graftable silane composition of claim 9 , wherein the free-radical initiator (iv) is selected from the group consisting of organic peroxides, organic peresters, azo compounds and combinations thereof and the anti-oxidant is selected from the group consisting of substituted phenols and substituted polyphenols, derivatives of phenylenediamine, ascorbic acid, tocopherols, tocotrienol, resveratrol, flavonoids, carotenoids, hydroxylamino compounds and combinations thereof.

13. The graftable silane composition of claim 9 , wherein at least one olefinically unsaturated [1,3,2]-dioxasilinane (ii) selected fro

Assignees

• Momentive Performance Mat Inc

Inventors

• Alam Samim
• Rojas Wahl Roy U

Classifications

• C08J3/24 Primary

  Crosslinking, e.g. vulcanising, of macromolecules (mechanical aspects B29C35/00; crosslinking agents C08K) · CPC title

• C08F230/08

  containing silicon · CPC title

• C08F255/02 Primary

  on to polymers of olefins having two or three carbon atoms · CPC title