CA1176782A

CA1176782A - Production of silane modified copolymers of alkylene- alkyl acrylates, polysiloxanes having combined therein organo titanates and the use thereof in the production of silane modified copolymers of alkylene- alkyl acylates

Info

Publication number: CA1176782A
Application number: CA000386696A
Authority: CA
Inventors: Michael J. Keogh
Original assignee: Union Carbide Corp
Current assignee: Union Carbide Corp
Priority date: 1980-09-30
Filing date: 1981-09-25
Publication date: 1984-10-23
Also published as: JPH0357882B2; JPS59500417A; KR860001033B1; EP0049155A2; ES8306381A1; PL129360B1; EP0104167A1; FI813049L; PL233254A1; IT8220240A0; AU8319982A; IL63927A0; DK498383A; ES510639A0; WO1983003353A1; CS713181A2; EP0107211A3; JPS57126804A; ES8400875A1; DE3280057D1

Abstract

ABSTRACT OF THE DISCLOSURE

The disclosure of this application is directed to the production of silane modified copolymers of alkylene-alkyl acrylates by reacting a mixture containing a polysiloxane, particularly an organo titanate containing polysiloxane and a copolymer of alkylene-alkyl acrylate to produce a water curable, silane modified copolmer. The silane modified copolymers can be extruded about electrical conductors to provide insulation thereon characterized by improved surface characteristics.

Description

PRODUCTION OF SILANE MODIFIED COPOLYMERS OF ALKYLENE-ALKYL AC~YLATES, POLYSILOXANES HAVING C~MBI~D THEREIN ORGANO
TITANATES AND THE ~SE THEREOF IN THE PRODUCTION OF SILANE
MODIFIED COPO~YMERS OF ALKYLENE-ALKYL ACRYLATES

SUMMARY OF THE INVENTION

rhis application relates to the production of silane modified copolymers o alkylene-alkyl acrylates, by the reaction of a polysiloxane and an alkylene-alkyl acrylate copolymer, which can be extruded about electrical conductors and water-cured, if so desired, to crosslinked products, providing insula-tion about electrical conductors which is characterized by improved surface characteristics. More particularly, this in-vention relates to polysiloxanes having combined therein an organo titanate and the use thereof in the production of silane modified copoly~ers of alkylene-alkyl acrylates.

67~2 BACKGROUND OF THE INVENTION
-Water-curable~ s~lane modified copolymers of alkylene-alkyl acrylates and a process ~or the preparatlon thereof by reacting a mixture containing a silane and an alkylene-alkyl acrylate copolymer are described ln detail in my U.S. Patent 4,291,136 granted September 22, 1981. The silane modified copolymers, as described in my U.S. Patent, can be extruded about electrical conductors such as wire and cable and water-cured to crosslinked products to provide insulation thereon of excellent quality.

It is customary, prior to extruding silane modified alkylene-alkyl acrylate copolymers about wire and cable, to in-sure rel~val therefrom of undesirable volatiles. The presence of undesirable vo~atiles could lead to the formation of voids in the extruded insulation, marring the appearance of the final insulated product and, in some instances, shortening its working life. In addition, removal of undesirable volatiles from the silane modified copolymers reduces odor problems at the ex-truder and in the insulated wire or cable. obviously, removal of volatiles from the silane modified copolymers, by a subse-quent devolatilization step after the preparation of the co-polymers,increases the time required to produce an insulated product and, also, increases the overall cost thereof.

DESCRIPTION OF THE INVENTION

The present invention provides for the production o~
silane modified copoly~ers of alkylene-alkyl acrylates which ~2-~76~
are free of undesirable volatiles and consequently need no~ be subjected to a subsequent devolat~lization step. The silane modi~ied copolymers, prepared in accordance with the present in-vention, c~n be direc tly extruded about wires and cables and water-cured ~o crosslinked products to provide insulation there-on, free of undesirable voids and odors.
In one aspect of thè present invention a silane modi-fied copolymer is produced by reacting a mixture containing an alkylenè-alkyl acrylate copolymer and a polysiloxane containing repeating units of the formula:

Formula I
~ V
_ -0 ~R ~ Si x wherein R is a hydrocarbon radical or oxy subtituted hydrocarbon radical; each V, which can be the same or different, is hydrogen, a hydrocarbon radical or a hydrolyzable group; Z is-a hydrolyzable group; n is an integer having a value of one to 18 inclusive and x is an integer having a value of at least ? 7 generally 2 to 1000 inclusive~ preferably 5 to 25 inclusive~
Illustrative of suitable hydrocarbon radicals for R
are alkylene radicals having one ~o 18 carbon atoms inclusive, preferably one to 6 carbon atoms inclusive, such as methylene, ethylene, propylene, butylene, hexylene and the like; alkoxy radicals having one to 18 carbon atoms inclusive, pre~erably one to 6 carbon atoms inclusive such as methyloxymethyl, methyloxy-propyl, ethyloxyethyl, ethyloxylpropyl, propyloxypropyl, propyl-oxybutyl, propyloxyhexyl and the like.

~7~i'782 As stated, each V can be hydrogen, a hydrocarbon rad-ical or a ~ydrolyzable group. Illustrative of suitable hydro-carbon radicals are alkyl radicals having one to 18 carbon rad-icals, preferably one to 6 carbon atoms inclusive such as methyl, ethyl, _-propyl, isopropyl, n-butyl, n-hexyl and the like; al-koxy radicals having one to 18 carbon atoms inclusive, prefer-ably one to 6 carbon atoms inclusive, such as methoxy, ethoxy, propoxy, hexoxy, dodecyloxy, methoxyethoxy and the like; aryl radicals having 6 to 8 carbon atoms inclusive such as phenyl, methyl phenyl, ethyl phenyl and the like~ cycloaliphatic radi-cals having S to 8 carbon atoms inclusive such as cyclopentyl, cyclohexyl, cyclohexyloxy and the like.
Z, as previously stated, is a hydrolyzable group among whieh can be noted alkoxy radicals as previously described for R; oxy aryl radicals such as oxyphenyl and the like, oxyali-phatic radicals such as oxyhexyl and the like; halogens such as chlorine and the like and other hydrolyzable groups as fur-ther described in U.SO Patent 3,408,420 to John B. Wiggill patented October 29, 1968.
Polysiloxanes having repeating units falling within the scope of Formula I can be prepared as described in U.S.
Patent 3,193,567 to Gerd Rossmy patented July 6, 1965 or by condensing and polymerizing a silane falling within the scope of Formula II in the presence of a meta~ carboxylate. Among suitable metal carboxylates can be noted dibutyltin dilaurate, stannous acetate, stannous octoate, lead naphthenate, zinc octoate, iron 2-ethyl hexoate and the like. Conditions employ-ed for the production of polysiioxanes, reaction temperatures, amount of materials and the like, using metal carboxylates as il76782 D-12137-2 catalysts ~re the same as subsequPntly ~escribed with respect to the use of organo titanates.
O ~
Formula II R- C-O t Rt~- Si- Z

wherein Rl is a hydrocarbon radical, as for example an alkyl rad-ical having one to 18 carbon atoms inclusive, preferably one to four carbon atoms inclusive such as methyl, ethyl, n-propyl,iso-propyl, n-butyl and the like, alkylene radicals having two to 18 carbo~ atoms inclusive, preferably two to 4 carbon atoms inclu-sive such as ethylene, propylene and the like; aryl radicals hav-ing six to ten carbon atoms inclusive such as phenyl, benzyl and the like. O~her variables are as previously defined.
Exemplary of suitable silanes falling within the scope of Formula ~I re the fol.lowing:

CH3~C-O-CH2cH2si~oc~3)3 acetooxyethyltrimethoxy silane CH3 C-O-CH~CH2Si(OCH2CH3)3 acetooxyethyltriethoxy silane CH3-c-o-cH2cH2si(oc2H4ocH3)3 acetooxyethyl-tris (2-methoxyethoxy) silane CH2-c-c~-o~cH2~t2sitocH3)3 methacryloxyethyltrimethoxy silane CH2=c - 8- ~ CH2~t3si~OcH2cH3)3 ~-met~yl.acryloxypropyltriethoxy silane O C,H3 CH3-C-O(CH2)2- Sli-OCH3 acetooxyethylmethyldimethoxy silane CH2= C-~C-O~CH2~3 Si~OCH3)3 ~-methacryloxypropyltrimethoxy silane _5_ D-12137-~
7~Z

CH3-C-O~C~2~3 Si(oCH3)3 acetooxypropyltrimethoxy silane o CH3 c~o~cH2?3 si(oCH2CH3)3 acetooxypropyltriethoxy silane C~12=~_C o~CH2)3Si~oC2~H40~H3)3 o ~-methacryloxypropyl-tris-(2-methoxyethoxy) silane preferred polysiloxanes, for purposes of this inven-tion, contain repeating units falling within the scope of Formula I and have combined therein an organo titanate. The organo titanate modified polysiloxanes can be used as such, withoutthe use of additional organo titanate catalyst, to react with the copolymers of alkylene-alkyl acrylate~
The preferred polysiloxanes have a viscosity of about 0.5 poise to about 150 poise, preferably about one to about 20 poise as determined by a Gardner-Holt bubble viscometer at a temperature of 25C.
Organo t~tanate modified polysiloxanes can be prepared by reacting a mixture containing a silane falling within the scope of Formula II with an organo titanate falling within the scope of Formula III.

Formula III Ti(OR2~4 wherein each R2, which can be the same or different, is hydrogen or a hydrocarbon radical having one to 18 carbon atoms inclusi~e, preferably one to 14 carbon atoms inclusive.

~ D-1~137-2 Exemplary of suitable hydrocarbon radicals are alkyl radicals such as methyl, ethyl, n-propyl, isopropyl, butyl, octyl, lauryl, myristyl, stearyl and the like, cycloa~iphatic radicals such as cyclopentyl, cyclohexyl and the like, aryl radicals such as phenyl, methylphenyl, chlorophenyl and the like;
alkaryl radicals such as benzyl and the like.
particularly desirable titanates falling within the scope of Formula III are those wherein each R2 is alkyl having one ~o 18 carbon atoms inclusive, prefer bly one to 14 carbon lo atoms inclusive~ exemplifled by tetrabutyl titanate, tetraiso-propyl titanate and the like.
organo titanates falling within th~ scope of Formula III are known compounds and can be conveniently prepared as des-cribed in U.S. patent 2,984,641 to Leon E. Wolinski patented May 16, 1961.
other suitable organo titanates are the organo titanium chelates such as ~etraoctylene glycol titanium, triethanol amine titanate, titanium acetyl acetonate, titanium lactate and the like.
At least a catalytic amount of organo titanate is used to produce the organo titanate modified polysiloxanes, that is an amount sufficient to catalyze the condensation and polymerization reactlon to produce a polysiloxane. As a rule, the amount of organo titanate used is on the order of about 0.001 to about 25 percent by weight based on the weight of ~he monomer-ic silane. It is preferred to use about 0.5 to about 5 percent by weight of organo titanate based on the weight ofthe monomeric silane.
The temperature at which the reaction is conducted can be varied over a wide range, for example from about 0C to about 250C.

~ 1~76782 D-12137-2 A tem~atureLn ~ ran~ ofabcut70Cto about ~0~ ispreferred.A~o the reaction ~n becond~ted using a suitable solvent,il~strated by hydro-~ bon solvents su~h ~ toluene, xylene, cumene, decaline, dodecane, chloro-benzene and the l~ke.
The reaction between the organo titanate and the mono-meric silane can be conducted under atmospheric~ subatmospheric or superatmospheric pressure. It is preferred to conduct the later stages of the reaction under subatmospheric pressure to allow for more facile removal of volatile by-products. Also, the reaction is preferably conducted under the atmosphere of an inert gas such as nitrogen or argon to avoid formation of a gel due to the water sensitivity of the product.
Control of the repeating unit, Formula I, of the poly-siloxane can be effected by introducing an end blocker, asforex-ample, a high boiling ester into the reaction mixture, at the beginning of the reaction or at any convenient point in the reaction process.
The number of repeating units of the polysiloxane is equal to the mole ratio of the monomeric silane to the end block-er as exemplified by the following simplified reaction scheme wherein the silane is shown to be acetooxyethyltrimethoxy silane and the high boiling ester is shown to be methyl benzoate.

O O
~ organo titanate CH3-c-o~cH2~-2 sitCH3)3 + ~ C 3 1 mole O.l mole 0 , CH3 c _ O~cH2~ si - _ OCH3 + CH3 -C-OcH3 CH3 lO

~7~
Suitable end blockers have the general formula R3-~-o-R3 wherein each R3, which can be the same or different, is a hydrocarbon radical as defined for R2.
Completion of the reaction is evidenced by cessation of the evolution of volatiles and the weight/volume of volatiles collected as compared to the theore~ical weight/volume. Al-ternatively, the reaction can be run to a desired viscosity level and the reactants cooled to s~op the reaction.
The alkylene-alkyl acrylate copolymers with which the p~lysiloxanes are reacted to form the silane modified copolymers are known copolymers produced by reactlng an alkene with an alkyl acrylate.
Suitable alkenes are ethylene~ propylene, butesle-l~
isobutylene, pentene-l, 2-methylbutene-1, 3-methylbutene-1 hexene7 heptene-l, octene-lvinyl chloride,styreneand the like.
The alkylene moiety of the alkylene-alkyl acrylate copolymer generally contains from 2 to 18 carbon atoms inclu-sive, preferably 2 to 3 carbon atc~s inclusive.
Suitable alkyl acrylate monomers which are copolymer-ized with the alkenes fall within the scope of the following formula:

Formula IV R
CH2=C-C=O
OR

wherein R4 is hydrogen or methyl and R5 is alkyl having one to 8 carbon atoms inclusive. Illustrative compounds encompassed by this formula are: methyl acrylate, ethyl acrylate, t-butyl ~7~i7~2 ~

acrylate, methyl methacrylate, n-butyl acrylate, n-butyl-methacrylate, 2-ethylhexyl acrylate and the like.
Alkylene-~lkyl acrylate copolymers generally have a density (ASTM D 1505) with conditioning as in ASTM D147-72) of about 0.92 to about ().94 and a melt index ~ASTM-1238 of 44 psi tested pressure) of about 0.5 to about 500 decigrams per minute.
For purposes of the present lnvent ion, the preferred copolymer is a copolymer of ethylene-ethyl acrylate, generally having about one to about 50 percent by weight combined ethyl acryla~e, preferably having about 2 to about 20 percent by weight combined ethyl acrylate.
The production of a s;lane modified copolymer of an alkylene-alkyl acrylate ;s carried out by reacting a polysilox-ane~ as described~ with a copolymer of an alkylene-alkyl acrylate in the presence of an organo titanate catalyst.
In those instances wherein the polysiloxane contains combined organo titanate, additional organo titanate catalyst may not be necessary, especially when at least about 0.5 percent by weight organo titanate, based on the weight of the monomeric silane, was used in the preparation of the polysiloxane.
The amount of organo titanate catalyst added to the reaction mixt~re is a catalytic amount,sufficient to catalyze the reaction between the polysiloxane and the copolymer. A
preferred amount is from about 0.001 to about 50 percent by weight, most preferably about 0.1 to about 25 percent by - weight based on the weight of the polysiloxane.
The amount of polysiloxane used can vary from about 0.05 to ~bout 10 and preferably about 0.3 to about 5 percent by -~L
D-12137-~
7~% ~

weight based on the weight of the copolymer.
The temperature at which this reaction is carried out is not critical and can vary9 conveniently, from about 80~
to about 300ac and preferably from about 150C to about 230C.
The reaction can be carried out at atmospherlc~ subat-mospheric or superatmo~h~c presslre~a~hough abmospheric pr~sure is preferred and in ~he presence of solvents as previously described.
Completion of the reaction is evidenced by measure-ment of no further viscosity change.
Recovery of the silane modified copol~mer is effected by allowing the contents o~ ~he reaction flas~ to cool and discharge to a suitable receiver for storage preferably under an inert gas blanket.
The reaction can be carried out in any suitable apparatus, preferably an apparatus in which the copolymer is subjected to mechanical working such as a Brabender mixer, a Banbury mixer or an extruder. The polysiloxane can be added to the fluxed copolymer and the organo titanate, if needed,then added. Alternatively, the organo t;tanate~ if needed,canbeadded to the copolymerprior to the addi~ion of the polysiloxane. Also,organo titanate and polysiloxane can be premixed andadded tothe fluxed polymer.
The reaction between the alkylene-alkyl acrylate co-polymer and the polysiloxane may be depicted by the following e~uation:
O V
l ¦¦ 6 l organo titanate C- C- 0 - R + -(R~n Si- _ ~
I l combined or added C V _ x segment of alkylene- 0 V
alkyl acrylate copolymer I ¦~ l C-C- -O(R ~ Si- _z C V

D~ 7 -wherein the variables are as previously defined and the silicon containing unit is present in an amount of at least about 0.05 percent by weight, generally about 0.1 to about 10 percent by weight and preferably about 0.3 to about 5 percent by weight based on the total weight of the modi~ied copolymer.

The curing or crosslinking of the silane modified alkylene-alkyl acrylate copolymer is effected by exposing the copolymer to moisture. The moisture present in the atmosphere is usually sufficient to permit curing to occur over a period of 48 hours.

The rate of curing, in a matter of 30 minutes, can be accelerated by exposure to an artifically humidifed atmosphere or immersion in water, and heating to elevated temperatures or ~y exposure to steam.

Generally, curing is effected at tempera-tures on the order of about 23C to about 100C, prefer-ably about 70C to about 100C.

D-121~
~'767~2 Additionally, the crosslinking may be carried out in the presence of ~ silanol condensation catalyst. A unique feature of this invention is that the crosslinking reaction can be carried out at signicant rates in the absence of added silanol condensation catalyst. The or~ano titanate catalyst or catalyst residues present in the production of the s~lane dified copolymers also eatalyze the crosslinking reaction.
Alternatively, a wide variety of materials which function as silanol condensation catalysts and which are known in the art can be employed in the crosslinking process. Such materials include metal carboxylates previously described;
organic bases such as ethylamine, hexylamine dibutylamine and piperidine and the like and acids such as mineral acids and fatty acids and the like.
To the silane modified copolymers of this invention may be added various additives,in amounts well known in the art,such as fillers among which can be mentioned carbon black, clay, talc, magnesium silicate, calcium carbonate, silica, aluminum hydroxide and the like.
The silane modified copolymers can be rendered flame retardant by the addition thereto of halogen containing flame retardants such as decabromodiphenyl oxide, chlorinated poly-ethylene, polyvinyl chloride and halogenated paraffin waxes, alone, or in admixture with organic or inorganic antimony compounds such as antimony oxide and/or alkaline earth, metal oxides, carbonates, hydroxides and sulfates. Among such alkaline earth metal compounds can be noted calcium oxide, calcium carbonate, calcium hydroxide, calcium sulfate, magnesium oxide, magnesium carbonate, magnesium hydroxide and magnesium D-12137 ~
~ 6~8~
sulfate.
It is to be noted that the disclosure of all patents noted are incorporated herein by reference.
The following examples further illustrate the present invention and are not intended to limit the scope there-~f.

A. Preparation o~ Polysiloxane The reaction scheme for the preparation of the poly-siloxane can be depicted as follows wherein ~he silane monomer was acetooxyethyltrimethoxy si~ane:

CH3-C-O-~CH2~ Si(OCH3)3 + organo titanate - OCH3 ¦ 0 -O tCH2t~-- Si - _ ~ CH3C-OCH3 OCH3 x = 8-9 One hundred and four grams (0.5 mole) of acetooxyethyl-trimethoxy silane were placed in a 250 ml. three-necked, round bottom flask and heated to a temperature of 75C under a nitro-gen gas atmosphere. When the contents of the flask reached a temperature of 75C, 1.191 grams of tetraisopropyl titanate were added thereto using a syringe. The reaction mlxture was heated for three hours at a temperature of 95C - 110C.
Volatiles evolved during the reaction and were condensed in a dry ice trap. At the end of the three hour period, the contents ~6~2 of the flask were cooled to room temperature, about 23C, the residue re ved from the flask~ weighed and stored under argon.

PERCENT
OF
YIELD ACTUAL THEORETICAL THEORETICAL
Volatiles 32.9 grams 37 grams 87 Polysiloxane product 69O0 grams 71.8 grams 96 Viscosity of Polysiloxane Product - 3.4 poise Infrared Analysis Volatiles strong absorption at 1685 reciprocal centi-meters which is consistent with strong adsorp-tion at 1690 reciprocal centimeters for a known sample of methyl acetate.

polysiloxane Product strong absorption at 1080 reciprocal centi-meters which is consistent with Si-0-CH3 group; weak absorption at 1692 reciprocal centimeters which is consistent with si~nficant reduction of carbonyl groups.

Value of n as 8-9 is consistent with viscosity of product and amount of volatiles recovered.

B. Preparation of Silane Modified Copolymer of Ethy~ene-Ethyl Acrylate To a 300 cc Brabender mixer heated to a temperature of 160C and maintained under a blanke~ of argon gas, there was added 244 grams of a copolymer of ethylene-ethyl acxylate, ~:~i7~

having 8 melt index o 1. and containing 16 percent by weight combined ethyl acrylate and 1.26 grams of 1,2-dihydro-2,3~4-trimethyl qulnoline, an antioxidant. Thls mixture was fluxed and mixed rapidly for 2 minutesc To the fluxed mixture, there was added, by means of a ~yrin~e, 5.80 grams of a mixture of the polysiloxane of (a) and d~butylt~n dilaurate. The 5.80 gram mixture contained 97 percent by weight polys~loxane and 3 per-cent by weight dibutyltin dilaurate. After homogeneity was reached in the Brabender, as indicated by a constant torque measurement, 1.26 ~rams of tetraisopropyl titanate were added to the contents of the Brabender. The contents of the Braben~
were then maintained at a temperature of 160-170C for a period of 30 minutes resulting in a reaction whereby the silane reac~
with the ethylene-ethyl acrylate copolymer as evidenced by an i~
crease in torque. Volatiles which evolved during the reaction were condensed in a dry ice trap which was connected to the Bra-bender. At the end of ~he 30 minute period, the contents of the Brabender were discharged into a polyethylene bag under an atmosphere of argon.
The volatiles which werè collected weighed 0.03 grams.

This example was conducted in the same manner as Example 1 with the exception that no additional tetraisopropyl titanate was used. The reactants and amounts thereof were as follows:

Ethylene-ethyl acxylate copolymer ~same as used in Example 1~ 246 grams 1,2-dihydro-Z,3,4-trimethyl quinoline 1.26 grams , D-1213,-2 i73~

Polysiloxane (prepared as described in Example lA) 5.80 grams The volatiles which were collected weighed 0.03 grams.
CONTR0~

To a 300 cc Brabender mixer heated to a temperature of 16~C and maintained under a blanket of argon gas, there was added 241 grams of a copolymer of ethylene-ethyl acrylate having a melt index o 1.2 and containing 16 percent by weight combined ethyl acrylate and 1.26 grams of 1,2~dihydro-2,3,4-trimethyl quinoline. This mixture was fluxed and mixed rapidly for 2 minute~. To the fluxed mixture, there was added, by means of a syringe, 8.84 grams of a mixture of ace~ooxyethyl-trimethoxy silane (CH3 -C-0-(CH2)2 Si(OCH3)3 and dibutyltin dilaurate. The 8.84 gram mixture contained 97 percent by weight acetooxyethyltrimethoxy silane and 3 percent by weight dibutyltin dilaurate. Af~er homogeniety was reached in the Brabender, as indicated by a constant torque measurement, 1.26 grams of tetraisopropyl titanate were added to the contents of the Brabender. The contents of the Brabender were then maintained at a temperature of 160-170C for a period of thirty minutes resulting in a reaction whereby the si]ane reacted with the ethylene-ethyl acrylate copolymer. Volatiles which evolved during the reaction were condensed in a dry ice trap ; which was connected to the Brabender. At the end of the thirty minute period, the contents of ~he Brabender were discharged into a polyethylene bag under an atmosphere of argon.
; The volatiles which were collected weighed 3.01 grams.

~L7~

20 gram samples of silane modi~ied copolymers of Example l, Example 2 and Control 1 were pressed into plaques of the following dimensions: 3 inches x 3 inches x .075 inch in a five minute cycle at a temperature of 110C-115~C under a pressure of 5000 psig.
The plaques were cured by being suspended in water, which was at a temperature of 90C,for three hours. After the three hour water-cure, the plaques were removed from the water, wiped dry and placed in a vacuum o~en, which was at a temperature of 50C, for one hour in order to insure removal of residual water.
The plaques were then measured for degree of cross-linking, according to the Monsanto Rheometer testO This test procedure is described, more fully, in U.S. Patent 4,018,852 to Donald L. Schober, granted April l9, 1977. Figure l of the drawing of this patent shows the typical Rheometer curve.
The level of vulcanization or crosslinking is designated as H
and is measured in terms of inch-pounds of torque on the Rheometer test equipment.
Results with respect to the plaques tested are as follows:
Average of ~2) Plaques Tested plaques o Example 1 53 inch-pounds Plaques of Example 2 53 inch-pounds Plaques of Control 1 53 inch-pounds Results show that a copoly~er reacted with a poly-siloxane has the same degree of crosslinking, with evolution of signficantly less volatiles, than a copolymer reacted with a monomeric silane.

E~AMPLE 3 This example illustrates the preparation of a poly-siloxane using an end blocker.
A three liter flask was charged with 2140 grams and 10.29 moles o~ acetooxyethyltrimethoxy silane, 154 grams (1.03 moles) of ethyl benzoate and the contents of th~ flask brought to a temperature of 85C. To this mixture, there was then added 21 grams of tetraisopropyl titanate. The solution, kept under an argon gas atmosphere, was stirred while being heated for 5 hours at a temperature of 94C-125C. During this period of time, 752 grams of volatiles were collected in an acetone dry ice trap. This was 98.8 percent of the theoretlcal amount of methyl acetate based on 100 percent conversion. The polysiloxane pro-duct recovered weighed 1543 grams, 99.3 percent of the theoreti-cal yield. Viscosity of the product was 1.4 poise. The equa-tion for the preparation is as follows:

O
CH3 -C-0 ~CH2~2 Si(OCH3)3 ~ ~ -C-OC2H5 organOti~te o C - -O-~CH2 ~ Si - - OC2H5+ CH3 -C-OCH3 OCH3 x=10 Example 3 was repeated using the same reactants, same molar amounts and same reaction conditions with the exception that acetooxyethylmethyldimethoxy silane was used as the mono-meric silane. Viscosi~y of the product ~as 1.4 poise.

The silane modified copolymers of alkylene-alkyl acrylates, although described primarily for use as insulation, can also be used as jacketing about industrial cables, telephone wires and cables.

Claims

CLAIMS:

1. Process of producing a water-curable, silane modified alkylene-alkyl acrylate copolymer which comprises reacting a mixture containing an alkylene-alkyl acrylate copolymer, a polysiloxane having the repeating unit:

wherein R is a hydrocarbon radical, or oxy substituted hydrocarbon radical, each V is hydrogen, a hydrocarbon radical or a hydrolyzable group and Z is a hydrolyzable group, n is an integer having a value of 1 to 18 inclusive, x is an integer having a value of at least 2 and an organic titanate.

2. Process as defined in claim 1 conducted at a temperature of about 80°C to about 300°C.

3. Process as defined in claim 1 conducted at a temperature of about 150°C to about 230°C.

4. Process as defined in claim 1 wherein the organo titanate has the formula:
Ti(OR2)4 wherein each R2 is hydrogen or a hydrocarbon radical.

5. Process as defined in claim 4 wherein each R2 is an alkyl radical having 1 to 18 carbon atoms inclusive.

6. Process as defined in claim 1 wherein the said copolymer is a copolymer of ethylene-ethyl acrylate.

7. Process as defined in claim 1 wherein R in the repeating unit of the silane is an alkylene radical having 1 to 18 carbon atoms inclusive.

8. Process as defined in claim 1 wherein R in the repeating unit of the silane is -CH2-CH2-.

9. Process as defined in claim 1 wherein each V in the repeating unit of the silane is methoxy.

10. Process as defined in claim 1 wherein the organo titanate is tetra-isopropyl titanate or tetrabutyl titanate.

11. Process as defined in claim 1 wherein the organo titanate is present in an amount of about 0.001 to about 25 percent by weight based on the weight of polysiloxane.

12. Process as defined in claim 1 wherein the polysiloxane is present in an amount of about 0.5 to about 10 percent by weight based on the weight of the copolymer.

13. Process as defined in claim 1 wherein the polysiloxane contains com-bined organo titanate.

14. Process as defined in claim 1 wherein the organo titanate is combined with the polysiloxane.

15. Process as defined in claim 1 wherein each V and Z of the polysiloxane are methoxy.

16. Process as defined in claim 1 wherein Z of the polysiloxane is methoxy, one V is methoxy and the second V is methyl.

17. Process as defined in claim 1 wherein the polysiloxane is derived from acetooxyethyltrimethoxy silane.

18. Process as defined in claim 1 wherein the polysiloxane is derived from acetooxyethylmethyldimethoxy silane.

19. Process as defined in claim 1 wherein the said copolymer is a copolymer of ethylene-ethyl acrylate and the polysiloxane is derived from acetooxy-ethyltrimethoxy silane.

20. Process as defined in claim 1 wherein the said copolymer is a copolymer of ethylene-ethyl acrylate and the polysiloxane is derived from acetooxy-ethylmethyldimethoxy silane.

21. A water-curable, silane modified alkylene-alkyl acrylate copolymer produced as defined in claim 1.

22. A water-curable, silane modified alkylene-alkyl acrylate copolymer produced as defined in claim 6.

23. A water-curable, silane modified alkylene-alkyl acrylate copolymer produced as defined in claim 14.

24. A water-curable, silane modified alkylene-alkyl acrylate copolymer produced as defined in claim 19.

25. A water-curable, silane modified alkylene-alkyl acrylate copolymer produced as defined in claim 20.

26. The cured product of the composition produced as defined in claim 1.

27. An insulated electrical conductor having thereon the cured product as defined in claim 26.

28. Process as defined in claim 1 wherein the mixture contains a silanol condensation catalyst.

29. Process as defined in claim 28 wherein the silanol condensation catalyst is dibutyltin dilaurate.

30. A water-curable, silane modified alkylene-alkyl acrylate copolymer produced as defined in claim 28.