CA2115714A1

CA2115714A1 - Copolymers of (meth)acryloxy-alkyl-siloxysilane and alkyl(meth)acrylates and the use thereof as pressure sensitive adhesives

Info

Publication number: CA2115714A1
Application number: CA002115714A
Authority: CA
Inventors: Xiaoling Li; Bret Berner
Original assignee: Ciba Geigy AG
Current assignee: Novartis AG
Priority date: 1993-02-17
Filing date: 1994-02-15
Publication date: 1994-08-18
Also published as: JPH06287239A; US5376378A; US5288827A; IL106809A0; EP0611783B1; AU671509B2; ATE164601T1; PH30471A; ES2114157T3; ZA941053B; KR940019739A; DE69409277D1; AU5508294A; DE69409277T2; NZ250876A; EP0611783A1

Abstract

COPOLYMERS OF (METH)ACRYLOXY-ALKYL-SILOXYSILANE AND
ALKYL(METH)ACRYLATES AND THE USE THEREOF AS PRESSURE SENSITIVE
ADHESIVES

Abstract The present invention relates to copolymers of certain siloxy silanes and alkyl (meth)acrylate. Especially preferred is the embodiment wherein the silyloxy silane is 3-methacryloxypropyl-tris(trimethylsilyloxy)-silane and the alkyl (meth)acrylate is 2-ethylhexyl acrylate. It further relates to pressure sensitive adhesives, especially medical adhesives, suitable for use in transdermal therapeutic systems (TTS).

Description

211t~
4-19464/A/CGC lG87 COPOLYMERS OF (METH)ACRYLOXY-ALKYL-SILOXYSILANE AND
ALKYL(METH)ACRYLATES AND THE USE THEREOF AS PRESSURE SENSITIVE
ADHESIVES

The present invention relates to copolymers of certain siloxy silanes and aLkyl (meth)acrylates. It further relates to pressure sensitive adhesives, especially medical ~ -adhesives. In addition, the invention further relates to transdermal and transmucosal drug delivery products and the pressure sensitive medical adhesives used therein.
: . .
Pressure sensidve adhesives (PSA) have been widely used in various f1elds for holding, protecting, sealing, and masking purposes. One application to the medical field is to the area of transdermal therapeutic systems (lTS). In the context of this speci~ication, unless specified otherwise, the term "transdermal" will refer collectively to transdermal and transmucosal and the term "skin" will refer respecdvely to skin or mucosa depending on whether a transdermal or transmucosal therapeutic system is under consideration. l[n addition to the general requirements for PSAs for general use, TrS require that PSAs be nonirritating to the skin, be physically and chemically compatible with the dmg(s) being administered, and be moisture resistant. PSAs must also adhere well to the skin, provide intimate contact of the l~S with the skin surface during application, and leave no residue upon removal.

PSAs that have been used in lTS are, among others, polyacrylates and polydimethyl-siloxanes. For example, aLkyl acrylates are tacky and pressure-sensitive and, therefore, do not require ~e addition of tackifying agents or plasticizers. Polydimethylsiloxanes (silicones) have been considered biocompatible and oxygen permeable. It is apparent that a PSA composed of acrylic and organic silicone types of polymers and retaining advantageous properties of each is desirable for use in l~S.

It has been known that a PSA should have a balance of cohesive and adhesive strength.
Such a balance has been attempted by incorporating two or more components with different properties by blending polymers or in some instances by copolymerization.
Polyalkyl acrylates, especially polyethylhexyl acrylate, are generally known as tacky, low -2- 21~7~ ~

glass transition temperature polymers. By incorporating a component with a h~gher glass transitis)n temperature and higher cohesive strength, an improvement of properties suitable for exploitation in a l-rS is expected.

It is an object of the invention to provide a new pressure sensitive adhesive suitable for use in medical practice, especially in transdermal and transmucosal drug delivery systems.

Surprisingly, these and other objects of the invention are realized with a copolymer of a silyloxy silane monomer of forrnula I with an alkyl (meth)acrylate monomer of formula II
and optionally other vinylic copolymerizable monomers. The silyloxy silane monomer is represented by the fonnula R1 o H2C=C--C~--R2--Si (OSi (CH3)3) 3-n(CH3)n ( )' wherein Rl is hydrogen or methyl, R2 is Cl 6alkylene, and n is an integer from O to 3, or mixtures tbereof. The aLkyl (meth)acrylate monomer is represented by the formula R3 o H2C =C--C--O--R4 (II), wherein R3 is hydrogen or methyl, and R4 is methyl or is unsubstituted linear or branched alkyl of 2-10 carbon atoms or mixtures thereof. Either of these two components comprises 42-58 mol % of the total monomer feed (exclusive of any polymerizationinitiator and crosslinker which may be present). The remainder is optionally made up of at least one copolymerizable vinylic monomer. In addition, the monomer feed contains a suitable amount of a polymerization initiator, and, whe~e desirable, a crosslinking agent.
The most preferred embodiment is when Rl is methyl, R2 is propyl, n is zero, R3 is hydrogen, and R4 is 2-ethylhexyl and the only monomers in the feed are those of formula I
and formula II.

The present invention relates to a copolymer composed of at least two monomers, the silyloxy silane of formula I and the aLkyl (meth)acrylate of formula II. Neglecting the polymerization initiator and any crosslinking agent that may be present, either or both of these monomers are fed into the polymerization reaction in amounts of 42 mol % to 58 mol %. The remainder to make up 100 mol % of the monomer feed may be another copolymerizable vinylic monomer. In the case where one of the two primary monomers of formula I and formula II, but not both, is below 42 mol % of the monomer feed, the -3- 2~ 7 balance can be made up from the addilional copolymerizable vinylic monomer Unless specifically stated otherwise, any monomer feed mol percent given will neglect any concentration of initiator and crosslinking agent which may be present.

The preferred silyloxy silane is represented by formula I, in which Rl is hydrogen or methyl, preferably methyl, R2 iS linear chain alkyl of 1 to 6 carbon atoms, preferably 2-5 carbon atoms, more preferably 3 or 4 carbon atoms, and most preferably n-propyl, and n is the integer 0, 1, or 2, most preferably zero. The most preferred compound of formula I is 3-methacryloxypropyl-tris(trimethylsilyloxy)-silane.

Other silyloxy silane compounds of formula I which are particularly suitable for preparing the claimed copolymer according to the present invention include, but are not limited to:

2-acryloxyethyl-dimethyl-trimethylsilyloxy-silane,2-acryloxyethyl-methyl-bis(trirnethylsilyloxy)-silane, 2-acryloxyethyl-tris(trimethylsilyloxy)-silane, 2-methacryloxyethyl-dimethyl-trimethylsiloxy-silane, 2-methacryloxyethyl-methyl-bis(trimethylsilyloxy)-silane, 2-methacryloxyethyl-tris(trimethylsilyloxy)-silane.

Also suitable are those corresponding compounds (I) wherein R2 is ethylene substituted at the l-carbon atom adjacent to the silicon with one methyl and substituted at the 2-carbon atom with acryloxyormethacryloxygroups.

Also suitable are those corresponding compounds (I) wherein R2 is n-propyl substituted at the 2- or 3-carbon atom or n-butyl substituted at the 2-, 3- or 4-carbon atom adjacent to the silicon with acryloxy or methacryloxy groups.

Also suitable are those corresponding compounds (I) wherein R2 is ethylene substituted at the 1-, at the 2-carbon atom, or at the 1- and 2-carbon atoms adjacent to the silicon with two methyl groups and substituted at the 2-carbon atom with acryloxy or methacryloxy groups.

Also suitable are those corresponding compounds (I) wherein R2 is n-propyl substituted at the 1- or at the 2-carbon atom adjacent to the silicon with methyl and substituted at the 2-or 3-carbon atom with acryloxy or methacryloxy groups.

The preferred alkyl (meth)acrylate is represented by the formula II, wherein R3 is 2~s~l~

hydrogen or methyl, preferably hydrogen, and R4 is branched or linear chain, preferably branched, alkyl of 1-10 carbon atoms, preferably 4-10 carbon atoms, more preferably 6-10 carbon atoms, even more preferably 8 carbon atoms, and most preferably 2-ethylhexyl.

Compounds of formula II particularly suitable for the instant invention include, but are not limited to: acrylate and methacrylate esters of the following unsubstituted alcohols:
methanol, ethanol, propanol, isopropanol, n-butanol, 2-butanol, 2-methylpropanol, tert-butanol, n-pentanol, 1-, 2- or 3-rnethylbutanol, 1,1-, 1,2- or 2,2-dimethylpropanol, 1-ethylpropanol, n-hexanol, 1- or 2-ethylbutanol, n-heptanol, 1-, 2- or 3-ethylpentanol, n-octanol, 1-, 2-, 3-, or 4-ethylhexanol, 2-ethyl-1-methylpentanol, 2-isopropylpentanol, 1,2-diethylbutanol, n-nonol, 1- or 2-ethylheptanol, 2-ethyl-1-methylhexanol, 2-ethyl-2-methylhexanol, 2-isopropylhexanol, n-decanol, 2-ethyloctanol, and 2,2-diethylhexanol.

The additional vinylic copolymerizable monomer is a monomer which can be polymerized together with the monomers of formulae I and II, but are not within the scope offormulae I or II. These monomers fall into two groups. Group A includes compounds which are substituted aLl~yl acrylates repreænted by the formula R5 o ll (III), H2C =C--C--O--R6 in which Rs is hydrogen or methyl and R6 is branched or linear substituted alkyl of 1-10 carbon atoms, preferably 4-10 carbon atoms, more preferably 6-10 carbon atoms, and most preferably 8 carbon atoms. The componds of formula III are selected from the same group as those of formula II except that those of formula III are substituted at the group R6 while those of formula II are unsubstituted at the corresponding group R4. The group R6 is substituted with at least one substituent. Multiple substituents are preferably identical.
Those substituents are selected from the group consisting of hydroxy, C~4alkoxy,halogen, carboxy, Cl4alkoxycarbonyl, C~4alkylcarbonyloxy, amino, preferably hydroxy.
Typical examples include, but are not limited to:

Mono-acrylate and mono-methacrylate esters of the following alcohols, which alcohols are further substituted as set forth below: methanol, ethanol, propanol, isopropanol, n-butanol, 2-butanol, 2-methylpropanol, tert-butanol, n-pentanol, l-methylbutanol, 2- or 3-methylbutanol, l,l-dimethylpropanol, 1,2-dimethylpropanol, 2,2-dimethylpropanol, 1-ethylpropanol, n-hexanol, 1- or 2ethylbutanol, n-heptanol, l-ethylpentanol, 2- or 3-ethylpentanol, n-octanol, 1-, 2-, 3- or 4-ethylhexanol, 2-ethyl- 1-methylpentanol, 2-7 1 ~
.. : .:

isopropylpentanol, 1,2-diethylbutanol,n-nonol, 1-ethylheptanol,2-ethylheptanol, 2-ethyl- l-methylhexanol, 2-ethyl-2-methylhexanol, 2-isopropylhexanol, n-decanul, 2-ethyloctanol, and 2,2-diethylhexanol.

The alcohols, which are further substituted, include those substituted by hydroxy, such as ~ -ethylene glycol, propylene glycol, glycerol, butylene glycol, 1,2,3-butanetriol, 1,4,6-hexanetriol, 2-hydroxyethylhexanol, 4-hydroxy-2-ethylhexanol, 4-hydroxymethyl-2-ethylpentanol, and 4-hydroxy-2-hydroxyethylhexanol, those substituted by Cl4alkoxy7 such as methoxy, ethoxy, propoxy, isopropoxy, and butoxy, such as 3-methoxy-2~
ethylhexanol or 4-ethoxy-2-ethyl-1-methylpentanol, halogen selected from Cl, F, and Br, such as 2-chloro-octanol or 2-(2-fluoroethyl)hexanol, carboxy, such as (l-carboxy or 2- ~ ~ -carboxy)-2-ethylhexanol, amino, such as 1-amino-2-ethylhexanol; as well as those having more than one substituent which are not identical, for example l-amino- 1-carboxy-2-ethylhexanol. Group A monomers further include vinylic acids such as (meth)acrylic acid, maleic acid, fumaric acid, itaconic acid, cinnamic acid, crotonic acid, 2-(meth)- ~ ;
acroyloxyethyl sulfonic acid, 2-(meth)acrylamido-2-methylpropane sulfonic acid, vinyl - ;~
sulfonic acid, p-styrene sulfonic acid, and allyl sulfonic acid. When present, these optional monomers do not exceed 5 mol %, preferably do not exceed 2.5 mol %, more preferably do not exceed 1 mol % of the total monomer feed.

The other group of the optional vinylic copolymerizable monomers, Group B, are non-(meth)acrylic vinylic monomers or they are (meth)acrylate amides, sulfonates or phosphonates. Examples include, without limitation: Mono- and dimethyl fumarate,diethyl fumarate, mono- and diisopropyl fumarate, mono- and dimethyl maleate, mono-and diisopropyl itaconate, mono- and diphenyl fumarate, methyl-phenyl-fumarate, bis-hydroxyethylmaleate, bis-hydroxyethylfumarate, a11yl alcohol, beta-allylethanol,vinylethylcarbinol, 2-hydroxyethylvinyl ether, vinyl acetate, vinyl alcohol, methyl-vinyl ether, vinyl propionate, vinyl benzoate, N-(l,1-dimethyl-3-oxobutyl)acrylamide, 2-hydroxyethyl-(meth)acrylamide, 2-hydroxypropyl-(meth)acrylamide, 3-hydroxypropyl-(meth)acrylamide, 2,3-dihydroxypropyl-(meth)acrylamide, poly(ethoxy)-ethyl(meth)-acrylamide, poly(ethoxy)-propyl(meth)acrylamide, sucrose (meth)acrylate, mannose .
(meth)acrylate, glucose (meth)acrylate, sorbitol (meth)acrylate, (meth)acrylamide, N-methyl and N,N-dimethyl(meth)acrylamide, N-2-hydroxyethyl(meth)acrylamide, N-3-hydroxypropyl(meth)acrylamide, bis- acetone (meth)acrylamide, methylol (meth)- ~:
acrylamide, vinyl formamide, vinyl acetamide, diacetophenone, allyloxyethane, N-vinyl pyrrolidone, N-vinyl acetamide, acrylonitrile, styrene, alpha-methylstyrene, t-butylstyrene, -:

~ , ~ . : , ;' ' . ~ ' :

21 ~ ~ 71~

Cl 4alkoxy-Cl 4alkyl (meth)acrylate and (meth)acrylamide, and ~he (meth)acrylates and (meth)acrylamides of the following groups: benzyl, t-butylphenyl, cyclohexyl, trimethylcyclohexyl, isobornyl, dicyclopentadienyl, norbornyl-methyl, glycidyl, Cl 4alkylthio-Cl 1alkyl, furfuryl, 2-(2-ethoxyethoxy)ethyl, hexafluoroisopropyl, l, l,2,2-tetrahydroperfluorododecyl, N,N-diethyl-aminoethyl, and N-t-butyl-aminoethyl. Still other monomers within this group include 2- or 4-vinyl pyridine, 2- or 4-methyl-5-vinyl pyridine, N-methyl-4-vinyl pyridine, l-vinyl imidazole, 2-methyl- l-vinyl imidazole, p-aminostyrene, o-aminostyrene, (dimethylaminoethyl)vinyl ether, vinyl pyrrolidine, 2-hydroxyethyl fumarate, bis-(2-hydroxyethyl) fumarate, 2-hydroxyethyl maleate, di-(2-hydroxyethyl)maleate, 2-hydroxyethyl itaconate, bis-(2-hydroxyethyl) itaconate, butyl-3-hydroxypropyl-bis-(hydroxy-poly lower aLkyleneoxide)fumarate, bis-(hydroxy-poly lower alkyleneoxide) maleate, bis-(hydroxy-poly loweralkyleneoxide) itaconate, or 2-phosphonatoethyl (meth)acrylate.

When these monomers are used in the embodiment in which the unsubstituted alkyl(meth)acrylate of formula II makes up less than 42 mol % of the monomer feed, they can be present in an amount not to exceed about 29 mol % of the total monomer feed, preferably about 25 mol %, more preferably not more than lS mol %, more preferably not more than lO mol %, even more preferably not more than 5 mol % of the total monomer feed. In the embodiment wherein the silyloxy silane of formula I is present less than 42 mol %, these monomers can be present in amounts not more than about 36 mol % of the total monomer feed, preferably mot more than 31 mol %, more preferably not more than lS mol %, more preferably not more than lO mol %, even more preferably not more than 5 mol % of the total monomer feed. In those embodiments wherein these additional optional monomers and the substituted alkyl(meth)acrylates of formula III are present simultaneously, the amounts set forth in this paragraph are inclusive of the amounts of the ~ -substituted alkyl(meth)acrylate monomers of formula III.
.
In embodiments in which both the compounds of formula I and formula II are present in amounts of or greater than 42 mol % of the monomer feed, the balance can be made up of no more than 5 mol %, preferably 2.5 mol %, more preferably l mol % of the monomers of Group A mentioned above, with any remainder being selected from the additional optional monomers of Group B set forth above.

Preferred embodiments of the present invention include polymers having a polymerization feed mixture of --211~7~
~ ~ .
-7- ~ ~;

(a) an effective amount of a polymerization initiator;
(b) O to 5 mol %, based on the total of all monomers present of a vinylic copolymerizable crosslinker; and (c) one of the following groups (i), (ii), or (iii); where (i) is (I) 42 mol % to 58 mol % of a silyloxy silane of formula I, ~ : :
(II) 42 mol % to 58 mol % of an unsubstituted aLkyl (meth)acrylate of formula II, (III) O to S mol % of a Group A monomer, and ~ ~:
(IV) O to 16 mol % of an additional vinylic copolymerizable monomer of Group B; or ~ : . -where (ii)is ~ :
(I) 42 mol % to 58 mol % of a silyloxy silane of formula I, (II) 21 mol % up to less than 42 mol % of an unsubstituted aL3cyl (meth)acrylate of formula II, (III) O to S mol % of a Group A monomer, and ~ :
(IV) O to 29 mol % of an additional vinylic copolymerizable monomer of Group B; or where (iii)is -(I) 16 mol % up to less than 42 mol % of a silyloxy silane of formula I, (II) 42 mol % to 58 mol % of an unsubstituted aLlcyl (meth)acrylate of formula II, (III) O to S mol % of a Group A monomer, and (IV) O to 36 mol % of an additional vinylic copolymerizable monomer of Group B; : ;
.
wherein in formula I Rl is defined as hydrogen or methyl; R2 is alkyl of 1-6 carbon atoms;
and n is an integer of from O to 3; and wherein in formula lI R3 is defined as hydrogen or methyl; and R4 is methyl or linear or branched chain C2 loalkyl which is unsubstituted;

and wherein Group A monomers are selected from (meth)acrylic acid, maleic acid, fumaric acid, itaconic acid, cinnamic acid, crotonic acid, fumaric acid, maleic acid, 2-(meth)acroyloxyethyl sulfonic acid, 2-(meth)acrylamido-2-methylpropane sulfonic acid, : ~
vinyl sulfonic acid, p-styrene sulfonic acid, allyl sulfonic acid, and rnonomers of ~:
formula III, in which R5 is hydrogen or methyl and R6 is a substituted linear or branched :
aL~cyl group of up tp 10 carbon atoms, said substituent being selected from the group consisting of hydroxy, Cl4alkoxy, Cl, Br, F, carboxy, Cl4alkoxycarbonyl, Cl 4aLIcylcarbonyloxy, and amino; and said additiona1 vinylic copolymerizable monomer :
is neither a polymeri~ation initiator, a crosslinker, nor a member of the group of compounds of formulae I, or II, nor a member of Group A as defined above, but is a mono-unsaturated monomer which is copolymerizable with compounds of formulae I, II, and members of Group A.

21~77~

The foregoing monomers of formula I, formula II, the optional monomers of Group A and the optional additional vinylic copolymerizable monomers of Group B are all available commercially or readily synthesized by procedures and processes commonly available and known to those of ordinary skill in the art as are the initiators and crosslinkers, which may also be present as discussed below. Typical commercial sources of these monomersinclude, but are not limited to: Huls America Inc. (Piscataway, N.J. USA), Shin-Etsu Chemical Co. (Tokyo, Japan), and Aldrich Chemical Company (Milwaukee, Wisconsin USA).

The most preferred copolymers of the invention are those which consist of formula I and formula II without any monomers of formula III or any other optional vinylic copolymerizable monomer being added. Within this group, the single most preferred polymer is 3-methacryloxypropyl-tris(trimethylsilyloxy)-silane as the sole compound of formula I and 2-ethylhexyl acrylate as the sole compound of formula II.

Polymerization is carried out by mixing the desired ratios of the monomers with an appropriate polymerization initiator, whether UV or heat polymerization initiator, and -where desirable with an appropriate amount of a suitable crosslinker. The polymerization mixture is then exposed to either UV irradiation or heat.

Typical thermal initiators include, but are not limited to: 2,2'-azo-bis-S2-amidinopropane) hydrochloride, 4,4'-azo-bis-4-cyanovaleric acid, l,l'-azo-bis-cyclohexanecarbonitrile, -2,2'-azo-bis-2,4-dimethylvaleronitrile, 2,2'-azo-bis-4-methoxy-2,4-dimethylvaleronitrile, 2,2'-azo-bis-isobutyronitrile, 2,2'-azo-bis-2-methylbutyronitrile, benzoyl peroxide, lauryl peroxide, decanoyl peroxide, acetyl peroxide, succinic acid peroxide, methyl-ethyl-ketone peroxide, propionyl peroxide, pelargonyl peroxide, p-chloro-benzoyl peroxide, bis-1- :
hydroxycyclohexylperoxide, dimethyl-2,2'-azobisisobutyrate, isopropyl percarbonate, tert-butyl peroctanoate, tert-butyl peroxyacetate, tert-butyl peroxypivalate, 2,5-dimethyl-2,5-bis-(2-ethylhexanoylperoxy)hexane, tert-butyl-peroxybutyrate, tert-butyl-peroxy maleic acid, tert-butyl-peroxy isopropyl carbonate, l,l'-bis-cyclohexane carbonitrile and mixtures thereof.
::
Typical UV initiators include, without limitation: benzoin, alpha-methyl benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, diketones, such as benzil and diacetal, acetophenone, tribromoacetophenone and the - ~ - - --. - -, ~ .

21~7~ ~

ortho-nitro derivative thereof, alpha,alpha-di(ethoxy)acetophenone, 1-hydroxycyclohexyl phenyl ketone, 2,2-dimethoxy-2-phenylacetophenone, 2-hydroxy-2-methyl-1-phenyl-1-propanone, benzophenone and its derivatives such as p,p'-tetramethylenediamine benzo-phenone, alpha-acryloximine esters such as benzil-(2-oxyethyl-oxycarbonyl)-alpha-monoxamine, benzil ketals such as benzil dimethyl ketal, benzil diethyl ketal, and 2,5-dichlorobenzil dimethyl ketal, phenothiazine, diisopropylxanthogen-disul~1de, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one, 2,2-dimethoxy-2-phenylacetophenone, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butan-1-one;2-hydroxy-2-methyl- 1 -phenylpropan- 1 -one; 2,4,6-trimethyl-benzoyldiphenylphosphine.

The typical range of molar ratios of monomer to initiator is 50:1 to 6000:1, preferably 50:1 to 1000:1, more preferably S0:1 to 500:1.

Typical crosslinkers include, but are not limited to: di(meth)acrylate ethylene glycol having 1 to 100 ethylyene oxide units, preferably 1 to 20 ethylene oxide units, more preferably 1 to 10 ethylene oxide units, lower alky1enediol di(meth)acrylate provided that there are no geminal oxygen atoms in the alkylenediol portion, ethylene glycol divinyl ether, glycerol tri(meth)acrylate, allyl~meth)acrylate, trimethylolpropane tri- or tetra-(meth)acrylate, pentaerythritol tri- or tetra-(meth)acrylate, divinyl benzene, divinyl ether, divinyl sulfone, bis-phenol-A-di-(meth)acrylate, ethoxylated bis-phenol-A-di-(meth)-acrylate, methylene-bis-(meth)acrylate, dimethylene-bis-(meth)acrylate, N,N'-dihydroxyethylene-bis-(meth)acrylamide, hexamethylene-bis-(meth)acrylamide, -decamethylene-bis-(meth)acrylamide, allyl maleate, diallyl maleate, triallyl melamine, diallyl itaconate, diallyl phthalate, triallyl phosphite, polyallyl sucrose, sucrose-di-(meth)-acrylate, glucose-di-(meth)acrylate, etc. - -The initiators and crosslinkers for use in the process of the present invention are readily available commercially, for example from the aforementioned suppliers, or can be readily synthesized by generally known methods.

The initiator/monomer reaction mixture is typically exposed to the initiating conditions (heat or UV light) for a period of about 20 seconds to 30 minutes, preferably 40 seconds to 10 minutes, more preferably 1 minute to about 5 minutes, most preferably l.S minutes to about 2.5 minutes, after which, the initiating condition need not be maintained. For purposes of this disclosure the initiator and any crosslinker which may be present is neglected in calculating the mol percents in the monomer feed or ~mal composition.

~ ,- : , . .: ~ . .

, . . ........................................ .
- - , 2~7 714 The copolymers of the invention can be recovered from the reaction vessels in manners typically known such as precipitation from methanol and other typical solvents, such as ethanol, and ethyl acetate. The polymers of the invention can then be utilized in any manner known for pressure sensitive adhesives. As stated earlier, the invention polymers are particularly advantageous for use in the medical adhesive area, especially as applied to transdermal drug delivery devices. Such devices have been widely described attempting to use other adhesives. Replacement of the adhesives in the devices described in the art with the instant invention copolymer adhesives results in achieving the objectives of the present invention.

The following Examples are presented to illustrate, but not limit the claimed invention.
.

3-methacryloxypropyl- tris-trimethylsilyloxy-silane (1) and 2-ethylhexyl acrylate (II) are fed into a reaction vessel in the molar amounts set out in Table 1 below. Benzoin methyl -ether is added in the amount indicated and the entire reaction mixture is exposed for two minutes to UV radiation of the indicated wavelength and intensity as set forth in Table I.
The resultant mass is then dissolved in tetrahydrofuran and the polymer is precipitated :
from methanol. -.

:,- . - ., ,,:, :

-11- 2~f77~

TABLE I
~ . .
EX. # AMOUNI' I1 AMOUNT II1 AMOUNT BME2 WAVE3 PoWER4 ~ :
LENGTH

3 30 70 500 365 4 ~ :

500 365 4 : ; :~
6 60 40 500 365 4 .
7 70 30 500 365 4 ::

13 42 ~8 1000 334 2 lMolar Fraction bssed on sum of I and 11.
2Molar ratio of (sum of I and 11) tc Ben~ioin Methyl Ether 3Wavelengtb in nm of light used for photoinitiation 4Power of emitted light in milliwatt per cm2 at surfsce of monomer solution '~.'-'''~

' -:
The products of Examples 1-9 are analyzed for final product monomer con~ent and the : ~:
resultant polymers are evaluated for co~iesive and adhesive strength. The results appear in Table II below.

- 12 - ~ 7 ~ 4 TABLE II

EXAMPLE# PRODUCTOF NALPOLYMERa 180PEEL
EXAMPLE# COMPOSITION ADHESIONb 14 1 7g.2:21.8 0.77c - -2 71.6:28.4 0.63C
16 3 62.8:37.2 0.97c 17 4 52.2:47.8 1.04 18 5 46.8:53.2 1.37 19 6 38.2:61.8 0.06d 7 26.0:74.0 0 04 21 8 17.0:83.0 e 22 9 13.6:86.4 e aFinal polymer molar ratios of I~
bPeel Adhesion in Kg/cm CCohesive failure was observed dAdhesives separated ~>m backing material eNo lack.

,:
The procedure of Example 1 is repeated except that either or both of the substituted allyl (meth)acrylate of formula m (A) and the additional copolymerizable vinylic monomer (B) are also present. The particular components and amounts are set forth in Table m below.

- 13 - 2 1 ~ .3 7 1 ~ :

TABLE IIIa EX. AMT II MT III MONOMER Ab AMT A MONOMER BC AMT B

23 50 21 ------ ----- vi-acetate 29 24 50 21 HEMA 4 vi-acetate 25 ------ ----- allyl alcohol 30 26 20 50 HEMA S allyl alcohol 25 27 42 42 ------ ----- N-vi-pyrrolid= 16 one 28 42 42 HEMA 4 N-vi-pyllolid= 12 one aAII amounts are mole % based on the sum of l+ll+A+l~
bHEMA = 2-HYDROXYETHYL METHACRYLATE
CVi=V~lYL

Claims

1. A polymer having a polymerization feed mixture of (a) an effective amount of a polymerization initiator;
(b) 0 to 5 mol %, based on the total of all monomers present, of a vinylic copolymerizable crosslinker; and (c) one of the following groups (i), (ii), or (iii); where (i) is (I) 42 mol % to 58 mol % of a silyloxy silane of formula I, (II) 42 mol % to 58 mol % of an unsubstituted alkyl (meth)acrylate of formula II, (III) 0 to 5 mol % of a Group A monomer, and (IV) 0 to 16 mol % of an additional vinylic copolymerizable monomer of Group B; or where (ii) is (I) 42 mol % to 58 mol % of a silyloxy silane of formula I, (II) 21 mol % up to less than 42 mol % of an unsubstituted alkyl (meth)acrylate of formula II, (m) 0 to 5 mol % of a Group A monomer, and (IV) 0 to 29 mol % of an additional vinylic copolymerizable monomer of Group B; or where (iii) is (I) 16 mol % up to less than 42 mol % of a silyloxy silane of formula I, (II) 42 mol % to 58 mol % of an unsubstituted alkyl (meth)acrylate of formula II, (m) 0 to 5 mol % of a Group A monomer, and (IV) 0 to 36 mol % of an additional vinylic copolymerizable monomer of Group B;

wherein in formula I:

(I) R1 is defined as hydrogen or methyl; R2 is alkyl of 1-6 carbon atoms; and n is an integer of from 0 to 3; and wherein in formula II:

(II) R3 is defined as hydrogen or methyl; and R4 is methyl or linear or branched chain C2-10alkyl which is unsubstituted;
and wherein Group A monomers are selected from (meth)acrylic acid, maleic acid, fumaric acid, itaconic acid, cinnamic acid, crotonic acid, fumaric acid, maleic acid, 2-(meth)acroyloxyethyl sulfonic acid, 2-(meth)acrylamido-2-methylpropane sulfonic acid, vinyl sulfonic acid, p-styrene sulfonic acid, allyl sulfonic acid, and monomers of formula III:

(III) in which R5 is hydrogen or methyl and R6 is a substituted linear or branched alkyl group of up to 10 carbon atoms, said substituent being selected from the group consisting of hydroxy, C1-4alkoxy, Cl, Br, F, carboxy, C1-4alkoxycarbonyl, C1-4alkylcarbonyloxy, and amino; and said additional vinylic copolymerizable monomer is neither a polymerization initiator, a crosslinker, nor a member of the group of compounds of formulae I, or II, nor a member of Group A as defined above, but is a mono-unsaturated monomer which is copolymerizable with compounds of formulae I, II, and members of Group A.

2. The polymer of claim 1 having the feed monomer composition of group (i).

3. The polymer of claim 1 having the feed monomer composition of group (ii).

4. The polymer of claim 1 having the feed monomer composition of group (iii).

5. The polymer of claim 1 wherein the silyloxy silane of formula I comprises about 45-55 mol % of the monomer feed composition.

6. The polymer of claim 1 wherein the alkyl (meth)acrylate of formula II comprises 45-55 mol % of the monomer feed composition.

7. The polymer of claim 1 wherein the siloxy silane of formula I comprises about 50 mole % of the monomer feed composition.

8. The polymer of claim 1 wherein the alkyl (meth)acrylate of formula II comprises about 50 mol % of the monomer feed composition.

9. The polymer of claim 1 wherein said feed monomer composition consists essentially of:
(a) 42 mol % to 58 mol % of the silyloxy silane of formula I; and (b) 42 mol % to 58 mol % of the alkyl (meth)acrylate of formula II.

10. A process of preparing the polymer of claim 1 characterized in that the feed monomer composition is polymerized in the presence of a polymerization initiator and optionally a crosslinker.