AU646291B2 - Terpolymers of maleic anhydride, C1-C5 alkyl vinyl ether and isobutylene or a C12-C14 alpha-olefin, and crosslinked products thereof - Google Patents

Description

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OPI DATE 18/02/92 AOJP DATE 26/03/92 APPLN. ID 84086 91 PCT NUMBER PCT/US91/04004 INTERNA. n. a. II n ,iv TREATY (PCT) :i i i (51) International Patent Classification 5 (11) International Publication Number: WO 92/01724 C08F 222/04, 210/14, 216/12 Al C08F 236/00 (43) International Publication Date: 6 February 1992 (06.02.92) (21) International Applicatiol Number: PCT/US91/04004 (74) Agents: MAUE, Marilyn, J. et al.; GAF Corporation, Patent Dept., Building No. 10, 1361 Alps Road, Wayne, NJ (22) International Filing Date: 7 June 1991 (07.06.91) 07470 (US).

Priority data: (81) Designated States: AT (European patent), AU, BE (Euro- 557,354 25 July 1990 (25.07.90) US pean patent), CA, CH (European patent), DE (Euro- 557,356 25 July 1990 (25.07,90) US pean patent), DK (European patent), ES (European pa- 564,920 9 August 1990 (09.08.90) US tent), FR (European patent), GB (European patent), GR (European patent), IT (European patent), JP, LU (European patent), NL (European patent), SE (European pa- (71)Applicant: ISP INVESTMENTS INC. [US/US]; 818 tent).

Washington Street, Wilmington, DE 19801 (US).

(72) Inventors: TAZI, Mohammed 33 Claremont Terrace, Published Wayne, NJ 07470 LOGIN, Robert, B. 137 Page With international search report.

Drive, Oakland, NJ 07436 KWAK, Yoon, T. 112 Avenue F, Brooklyn, NY 11218 GANGADHAR- AN, Balgopal 87 estville Avenue, Caldwell, NJ 07006 HALDAR, Rama, K. 8 Sweetwood Drive, Randolph, NJ 07006 PLOCHOCKA, Krystyna 2305 Mountain Avenue, Scotch Plains, NJ 07076 RIZ- ZO, Thomas 105 Kirkfield Drive, Cary, NC 27511

(US).

(54)Title: TERPOLYMERS OF MALEIC ANHYDRIDE, CI-C 5 ALKYL VINYL ETHER AND ISOBUTYLENE OR A C12-C 1 4 ALPHA-OLEFIN, AND CROSSLINKED PRODUCTS THEREOF (57) Abstract Terpolymers of maleic anhydride, a Ci-C 5 alkyl vinyl ether and isobutylene or a C 12

-C

14 alpha-olefin, and crosslinked products thereof, are provided herein for use in thickener, denture adhesive, sunscreen, hair spray, and waterproofing compositions. The alpha-olefin comonomer is a hydrophobic, straight chain, unsaturated hydrocarbon such as dodecene or tetradecene, which is present in the terpolymer in predetermined amounts relative to the hydrophilic maleic anhydride component, to provide a terpolymer having a suitable HLB for these applications. The isobutylene comonomer provides hydrophilic terpolymer compositions which are particularly useful as denture adhesives.

WO 92/01724 PCT/US91/04004 1 TERPOLYMERS OF MALEIC ANHYDRIDE, C 1 -Cg ALKYL VINYL ETHER AND ISOBUTYLENE OR A C12-14 ALPHA-OLEFIN, AND CROSSLINKED PRODUCTS THEREOF This invention relates to terpolymers of maleic anhydride, a C 1

-C

5 alkyl vinyl ether and isobutylene or a C 12

-C

14 alpha-olefin, and tr -rosslinked products thereof, which are provided within predetermined compositional ranges for application in denture adhesive, sunscreen, hair spray and waterproofing compositions, and for effective compatibility with organic solvents.

Copolymers of maleic anhydride and alkyl vinyl ethers are well known in the art and are conventionally prepared by free radical precipitation polymerization of the monomer mixture in an aromatic hydrocarbon solvent such as benzene in the presence of a protective colloid.

Another method involves copolymerization of maleic anhydride, an alkyl vinyl ether and/or a C 3

-C

10 alkene in contact with a powder bed. In the latter method, disclosed in U.S. Patent 4,370,454, a large excess of the alkyl vinyl ether and/or alkene, e.g. 3 to 25, preferably to 15, moles thereof, per mole of maleic anhydride monomer, is present during the polymerization, instead of the usual 1:1 mole ratio required of the copolymer. In the powder bed method, the heat generated during polymerization is removed by evaporating the excess alkyl vinyl ether and/or alkene which boils at a lower temperature than maleic anhydride. The examples in this patent were directed to copolymers of maleic anhydride and alkyl vinyl ethers, or copolymers of maleic anhydride and alkene.

SWO 92/01724 PCT/US91/04004 2- What is provided herein are terpolymers of maleic 1 anhydride a C 1

-C

5 alkyl vinyl ether (AVE) and isobutylene (IB) or a C 12

-C

14 alpha-olefin and crosslinked products thereof, for use in thickener, denture adhesive, sunscreen, hair spray and waterproofing compositions.

'p Suitably, the molar ratio of MA:AVE:AO in the terpolymer is about 1:0.90-0.99:0.01-0.10, preferably about 1:0.94-0.96:0.04-0.06, respectively. Representative

C

1

-C

5 alkyl vinyl ethers include methyl vinyl ether, propyl vinyl ether and butyl vinyl ether. Suitable

C

12

-C

14 alpha-olefins are straight chain unsaturated hydrocarbons such as dodecene and tetradecene. Crosslinked products of such terpolymers with such crosslinking agents as 1,7-octadiene and 1,9-decadiene also are provided herein.

Suitably the molar ratio of MA:AVE:IB is about 1:0.4-0.9:0.1-0.6, preferably about 1:0.5-0.8:0.2-0.5. As denture adhesives, the terpolymer provided has a weight average molecular weight of about 30,000 to preferably about 50,000 to 350,000, and in the form of a i mixed, partial salt such as the calcium/sodium salts wherein the equivalent ratio of calcium to sodium cations may range from 2:1 to 10:1, preferably between 3:1 to 7:1, and the degree of neutralization of initial carboxyl groups is from 0.5 to 0.95, preferably from 0.7 to 0.9.

The terpolymers products of the invention are I particularly characterized by a predetermined ratio between the hydrophobic, straight chain unsaturated C12-C14 hydrocarbon component and the hydrophilic, maleic anhydride component, which ratio affords a suitable hydrophilic-lipophilic balance (HLB) for the terpolymer and its crosslinked derivative.

i% WO 92/01724 PCT/US91/04004 3 A preferred process for making the terpolymers of the invention also is characterized in that the monomers are polymerized in a mixed solvent comprising a cycloaliphatic hydrocarbon such as cyclohexane and an aliphatic carboxylic ester such as ethyl acetate.

In this process, a suitable reactor is provided with appropriate inlet tubes, agitation means, and heater and temperature control means. The reactor is first purged with nitrogen to remove air from the system. Generally three separate purges are employed, at about 3 bars pressure and about 40 0 C. The reactor is precharged with maleic anhydride and the crosslinking agent in a suitable solvent which may be an aromatic hydrocarbon such as benzene or toluene but is preferably a mixed solvent of a cycloaliphatic hydrocarbon such as cyclohexane and an ester of an aliphatic carboxylic acid such as ethyl acetate. A solvent system which is a 50:50 mixture of cyclohexane and ethyl acetate is preferred.

The precharged reactor is purged with nitrogen at about 580C. and a free-radical polymerization initiator is introduced in three stages during the polymerization, generally at the beginning, after about 1-1/2 hours and finally after about 3 hours, for a polymerization period of about 3 hours. Alternately, the initiator can be introduced in a continuous manner, e.g. as a solution in the reaction solvent. Any suitable initiator known in the art may be used including but not limited to peroxides.

Tertiary butyl or tertiary amylperoxy pivalate are preferred. The concentration of initiator may vary widely, although suitably the initiator comprises about 0.05 to 2% by weight of the maleic anhydride reactant.

I IL~~I ~i WO 92/01724 PCT/US91/04004 4 Then, simultaneously with feeding of initiator, the alkyl vinyl ether and isobutylene or alpha-olefin monomers are introduced separately or together into the precharged reactor, and at a controlled rate, during the course of the polymerization.

Overall, the molar ratio of maleic anhydride to the combined alkyl vinyl ether and isobutylene or alpha-olefin monomers in the process is set at about less than 1:1. In practice about a 10% excess of the alkyl vinyl ether over the 1:1 ratio is used to ensure complete conversion of the maleic anhydride to the terpolymer. The molar amounts of alkyl vinyl ether present in the terpolymer is about 0.4-0.9, preferably 0.6-0.8, and the molar amounts of isobutylene present in the terpolymer is about 0.1-0.6, preferably about 0.2-0.5.

The molar amount of C 12

-C

14 alpha-olefin present in the resultant terpolymer is about 0.01-0.10, preferably 0.04-0.06. The crosslinker, when present, 1 corresponds to about 5 wt. of total monomers in the terpolymer. The predetermined amount of hydrophobic

C

12

-C

14 alpha-olefi- in the terpolymer will provide terpolymers with a suitable HLB for various commercial applications.

Of course, during the polymerization, the reaction Imixture is agitated effectively, and, at the conclusion of I the polymerization, the reaction product is held at the polymerization temperature for about 1-1/2 hours. Then excess alkyl vinyl ether is vented and the product is discharged, filtered and the fine powders of the terpolymer is dried.

For use as a denture adhesive, the terpolymer is converted to its mixed, partial salt, which preferably is employed as a dry powder having a particle size of less than 250 J, and, more desirably, a particle size of from about 5 to about 200 P.

_L

W3 92/01724 PCT/US91/04004 5 Denture adhesive compositions are provided herein by incorporating dry powders of the above adhesive copolymer as mixed salts into a liquid base carrier by mixing until a homogeneous cream paste suspension or collodial dispersion is obtained, usually within a period of from about 20 minutes to about 5 hours. The resulting composition contains an effective adhesive amount of the adhesive copolymer mixed salt, generally between about and about 50 wt. and preferably between about 10 and about 35 wt. of the final composition.

Suitable rtlxed partial salts herein include the calcium/sodium mixed partial salts which are prepared by reacting the copolymer with suitable bases. Preferably the equivalent ratio of calcium cations to sodium cations in the mixed partial salts may range from 2:1 to 10:1 and most preferably is between 3:1 and 7:1 (on a mole ratio basis, the range of calcium to sodium cations is from 1:1 to 5:1, most preferably from 1.5:1 to The sum total of cations in the mixed partial salt should be sufficient to give a degree of neutralization of from 0.5 to 0.95 and preferably 0.7 to 0.9 of the total initial carboxyl groups in the copolymer. In the determination of the total initial carboxyl groups in the copolymer, the anhydride radical is considered as containing 2 initial carboxyl groups.

The base carrier portion of the composition generally includes a water soluble or partially water soluble hydrophilic carrier which is capable of swelling upon exposure to moisture to form a mucilaginous mass.

Such carrier materials include natural and synthetic gums, viscous liquids, gels and powders. Among those suitably employed as base carriers in the composition are karaya gum, gelatine, gum tragacanth, gum acacia, gum shiraz, algin, oodium alginate, tragacanth, methyl cellulose, a mixture o petrolatum and mineral oil, glycerine, SWO 92/01724 PCT/US91/04004 6polyvinylpyrrolidone, K-30 and K-90, carboxymethyl cellulose, ethylene oxide polymers, of which the preferred is a mixture of petrolatum and mineral oil in a ratio of S40:60-60:40.

The adhesive terpolymer of the invention can be employed as the sole adhesive component in the denture adhesive composition or it can be used as a coadhesive with another adhesive material. Such adhesive additive, if present, will generally comprise about 5-20% by weight of the composition. Suitable adhesive additives include natural or synthetic polymers such as cellulose, karaya gum, gum tragacanth, gum acacia, carboxymethyl cellulose or salt thereof, polymethacrylate, polyvinylpyrrolidone, polyvinyl acetate, or any mixture of the above.

The compositions of the invention are particularly useful for affixing dentures and can also be used in surgical procedures which require temporary displacement of Stissue. As a denture adhesive, the thermal stability of the present composition, over a temperature range which is at least sufficient to embrace all conditions encountered by living tissue, e.g. 5 0 is particularly desirable. Because of their increased adhesive strength and thermal stability, the composition retains its adhesive properties over a long period of time, i.e. up to 24 hours.

The following illustrates a few representative formulations into which the adhesive terpolymer can be added in effective amounts up to about WO 92/01724 PCT/US91/04004 -7 Cream Denture Adhesive Composition Wt. Mineral Oil Petrolatum Sodium carboxymethyl cellulose (adhesive additive) Colorant 1 Flavoring Agent Material of Invention 23.5 Paste Ostomy Adhesive Composition Wt. Mineral oil (heavy) Glycerine Polyvinylpyrrolidone Carboxymethyl cellulose Tosylate of quat. amino-N-propylpyrrolidone Matrial of Invention 34.5 Denture Adhesive Powder Composition Wt. Gum tragacanth Gum acacia Spearmint oil 0.05 Material of Invention 39.05 WO 92/01724 PCT/US91/04004 8 EXAMPLE 1 98 g. (1.00 mole) of maleic anhydride (MA) and 21.04 g. (0.125 mole) of dodecene (DD) in 534 g. of toluene was precharged in a reactor equipped with suitable inlet tubes, agitation means, and heater and temperature control means, and the reactor was purged three times with nitrogen at 50 psi nL igen pressure at 58 0 C. Then 3.92 g. (4 wt. on MA) of Lupersol 11 in 15 g. of toluene was added at a rate of 9.9 ml/min. Simutaneously, 55.12 g. (72.13 ml) (0.95 mole) of methyl vinyl ether (MVE) was fed into the reactor over a period of 4 h6urs while agitating .the reaction mixture at about 280 rpm. The reactant monomers corresponds to 23% solids in this solvent system. The reactor was held at 58 0 C. for 1 hour, cooled, excess methyl vinyl ether was vented, the product was discharged from the reactor, filtered, washed, and dried.

A solid product was obtained which had a molar ratio of maleic anhydride to methyl vinyl ether to dodecene S(MA:MVE:DD) of about 1.0:0.95:0.05. The yield was 147.3 g.

The specific viscosity was 0.15 as measured in 1% methyl ethyl ketone, viscometer I 616, size 100.

SEXAMPLE 2 S-j 60.0 g..(0.612 mole) of maleic anhydride was precharged into a reactor with 4.78 g. (0.343 mole) of tetradecene, 4.78 g. (0.0434 mole) of 1,7-octadiene and 420 g. of a 50:50 mixture of cyclohexane and ethyl acet'" k. The reactor was purged with nitrogen and heated to 58 Then a mixture of 39.09 g. (50.88 ml., 0.365 mole) o. ethyl vinyl ether was admitted into the reactor slowly over a period of 3 hours. Simultaneously, three portions of 0.1 g. each based on MA) of Lupersol 11 were admitted during the polymerization. After 3 hours, li WO 92/01724 PCT/US91/04004 9 the reaction product was held at 58 0 C. for 1-1/2 hours, cooled to room temperature, excess methyl vinyl ether vented and the product was discharged, filtered and dried to provide a fine, dry crosslinked terpolymer product.

The crosslinked terpolymer comprised a molar ratio of maleic anhydride to methyl vinyl ether to tetradecene (MA:MVE:TD) of about 1.0:0.96:0.04 and was crosslinked with by weight of 1,7-octadiene based on the total weight of the terpolymer.

EXAMPLE 3 The terpolymer was crosslinked with other crosslinking agents selected from dienes, divinyl ethers and allyl carbohydrates with similar results.

EXAMPLE 4 The 1,7-octadiene crosslinker was introduced with the externally fed monomers. The reaction product slurry was thick but filterable, and it was dried at 65 0 C. in vacuum oven.

The crosslinked terpolymers prepared above found particular application in thickener, adhesive, sunscreen, Shair spray and waterproofing compositions.

WO 92/01724 PCT/US91/04004 S- EXAMPLE 1A g. (0.67 mole) of maleic anhydride in 194 g. of a 50:50 mixture of cyclohexane and ethyl acetate was precharged in a reactor equipped with suitable inlet tubes, agitation means, and heater and temperature control means, and the reactor was purged three times with nitrogen at 3 bar pressure and at 58 0 C. Then 0.217 g. of Lupersol ii in 2 g. of a 50:50 mixture of cyclohexane and ethyl acetate was added. Simutaneously, a mixture of 28.9 g. (37.6 ml., mole) of methyl vinyl ether and 9.3 g. (15.8 ml., 0.17 mole) of isobutylene was fed into the reactor over a period of 3 hours while agitating the reaction mixture at about 180 rpm. Two additional portions of initiator of 0.217 g.

each were introduced after 1-1/2 and 3 hours. The reactant monomers constitute a 20% solids mixture in this solvent system. The reactor then was held at 58 0 C. for 1-1/2 hours, cooled, excess methyl vinyl ether was vented and the product was discharged from the reactor. The desired powder terpolymer was obtained by filtration; it had a molar ratio of maleic anhydride to methyl vinyl ether to i isobutylene of 1:0.75:0.25, which was substantially the same ratio as the reactants used in the process.

Ii WO 92/01724 PCT/US91/04004 11 EXAMPLES 2A 12A The process of Example 1A was followed to provide the terpolymers of desired compositions using monomers of different feeding composition and in various solvent systems.

TABLE 1 Molar Composition of Reactant Monomers in Examples 2A 12A Ex. No.

2A 3A 4A 6A 7A 8A 9A 11A 12A Maleic Anhydride 1 1 1 1 1 1 1 1 1 1 1 Methyl Vinyl Ether 0.85 0.80 0.55 0.60 0.50 0.82 0.75 0.83 0.88 0.50 0.25 Isobutylene 0.25 0.25 0.55 0.60 0.50 0.28 0.25 0.28 0.28 0.50 0.75 Solvent

CH/EA

CH/EA

CH/EA

CH/EA

toluene toluene benzene bc f:ene bCnzene benzene benzene The molar composition of the was substantially the same as that of monomers in the process.

terpolymer obtained charged reactant i -riri SWO 92/01724 PCT/US91/04004 12 EXAMPLE 13A 65.0 g. (0.663 mole) of maleic anhydride was precharged into a reactor with 5.33 g. (0.048 mole) of i,7-octadiene and 535 g. of toluene. The reactor was purged with nitrogen and heated to 58 0 C. Then a mixture of 21.17 g. (27.67 ml., 0.365 mole) of methyl vinyl ether and 20.46 g. (34.81 ml., 0.365 mole) of isoLutylene was admitted into the reactor slowly over a period of 4 hours.

Simultaneously, three portions of 0.65 g. each of Lupersol 11 was admitted during the polymerization of 4 hours. .Then the reaction product.was held at 58 0 C. for 1 hour, cooled to room temperature, excess methyl vinyl ether was vented and the product was filtered. 100.5 g. of dry terpolymer powder was collected.

The crosslinked terpolymer obtained in this manner had a molar ratio of maleic anhydride to methyl vinyl ether to isobutylene of 1:0.50:0.50 and was crosslinked with by weight of 1,7-octadiene based on the total weight of the terpolymer.

SEXAMPLE 14A The terpolymer was crosslinked with other i crosslinking agents selected from dienes, divinyl ethers and allyl carbohydrates with similar results.

EXAMPLE i The 1,7-octadiene crosslinker was introduced with the externally fed monomers. The reaction product slurry was thick but filterable, and it was dried at 65 0 C. in vacuum oven. 98.9 g. of a dry product comprising the crosslinked terpolymer was obtained.

AJ

WO 92/01724 PCT/US91/04004 13 EXAMPLE 1B A 1-liter resin kettle was equipped with a stirrer, reflux condenser, a N 2 inlet tube and an inlet closed with a rubber septum for introduction of a polymerization initiator. The kettle was charged with 60.0 g. (0.61 mole) of maleic anhydride 97.9 g. wt. of ethyl acetate (EA) and 97.9 g. (50 wt. of cyclohexane Agitation of the mixture at 180 rpm was begun, and the system was purged by bubbling in N 2 for minutes, during which time the maleic anhydride dissolved completely. The reaction mixture was then warmed to 58 0

C.

and 0.2 g. of Lupersol 11 (Pennwalt) was injected through the septum to initiate polymerization. Simultaneously, dropwise addition of 19.6 g. (0.33 mole) of methyl vinyl ether (MVE) and 18.88 g. (0.33 mole) of isobutylene (IB) was begun and continued over a period of 3 hours.

Lupersol 11 was added in an amount of 0.4 g. after 1-1/2 hours. After completion of all additions, which required 58 0 the resulting mixture was maintained at 58 0 C. for.

1-1/2 hours. Thereafter, the reaction mixture was cooled to room temperature, excess MVE vented and the slurry was pumped out of the kettle into a filtration unit. There the slurry was filtered and the polymer product was dried for about 12 hours at 65 0 C. in a forced air oven. The polymer product was a uniform, fine white powder, having a molar ratio of MA:MVE:IB of 1:0.55:0.55.

EXAMPLE 2B The procedure of Example 1B was followed to provide copolymers of varying compositions within the molar range of 1:0.4-0.9:0.1-0.6, including one at 1.0:0.75:0.25.

Ii SWO 92/01724 PCT/US91/04004 14 EXAMPLE 3B i PREPARATION OF DENTURE ADHESIVE COMPOSITIONS OF INVENTION The terpolymers of Examples 1B 2B were converted ito their mixed, partial salts illustrated as follows: 58.6 g. of the terpolymer was charged into a 250 ml round bottom, 3-necked flask together with 260 g. of isopropyl alcohol. The contents were agitated to make a slurry and 18.1 g. of calcium hydroxide was added slowly with agitation during 15 minutes. Then 2.85 g. of sodium hydroxide dissolved in 112.5 g. of water was added with agitation. The mixture was heated at 45 0 C. with agitation for 4-1/2 hours. The pH of the liquid phase was 6.1. The mixture was filtered and the precipitate was dried in a vacuum oven overnight at 65 0 C. to provide 93.4 g. of a dried product. Similar copolymer conversions to the mixed .partial salts were effected for the terpolymers of I Example 2B.

SEXAMPLE 4B PREPARATION OF ADHESIVE COMPOSITIONS FOR INSTRON TESTING 1 The dry, mixed salt of the MA/MVE/IB terpolymer of Example 1B was milled to pass through a number 60 mesh sieve (250 u) and the resulting powder was then dispersed at a temperature of 55-65 0 followed by cooling to 20-25 0 into a petrolatum base using mechanical stirring. The ratio of copolymer to base by weight was 1:2. The resulting cream dispersion was collected as the desired adhesive composition.

WO92/01724 PCT/US91/04004 15 EXAMPLE I Adhesive compositions of GANTREZ MS-955, which is a commercial mixed salt copolymer of maleic anhydride and methyl vinyl ether, also were prepared for testing in the same manner as described above for Examples 1B 2B.

EXAMPLE 6B EVALUATION OF DENTURE ADHESIVE COMPOSITIONS 2 g. samples of each of the above prepared compositions were evaluated for adhesion characteristics by Instron testing according to the following procedure: SIn the first step, the upper and lower plates of the Instron apparatus were brought together to obtain a zero position. The upper plate was then raised 0.06 inch I and the upper cycle limit on the Instron indicator is set i at this point. The upper plate was then lowered and the lower cycle limit was set. In its lowest position, the iupper plate was distanced 0.03 inch above the lower plate.

With these Instron settings determined, the upper plate was then raised and 2 g. of the test sample was Suniformly spread over the surface of the lower plate in a i 1/16 to 1/8 inch thickness; thereafter simulated salivary fluid was applied over the sample so that it was barely covered.

I The Instron crosshead was cycled between the Spreviously set limits at a crosshead speed of 0.2 in./min.

The Instron chart was set in the continuous mode at a speed of 2 in./min. to record the compression and adhesion force for each cycle, 5 to 100 cycles.

WO 92/01724 PCT/US91/04004 16 At the end of 100 cycles, the motion of the upper plate was halted and raised high .enough to clean the surface before the next adhesive test.

Each recording was analyzed and the adhesional forces (Ibs.) for the 1st, 5th, 10th, 20th, 40th 100th cycles were recorded and then plotted graphically.

The results of this study are shown in the FIGURE which data show that significantly better initial stick strength and long term adhesion is obtained for adhesive formulations containing the terpolymer compositions of the invention as compared to a related copolymer composition (MS-955), which is considered useful as a denture adhesive.

I:

Claims (6)

1. A terpolymer comprising maleic anhydride, a C1-C 5 alkyl vinyl ether and isobutylene or a C 12 -C 14 alpha-olefin, optionally crosslinked with a crosslinking agent, wherein the molar ratio of maleic anhydride, said alkyl vinyl ether and isobutylene, when s present, is about 1:0.4-0.9:0.1-0.6, and the molar ratio of. maleic anhydride, said alkyl vinyl ether and said alpha-olefin, when present, is about 1:0.9-0.99:0.01-0.10.

2. A terpolymer according to claim 1 which comprises maleic anhydride, a C 1 -C alkyl vinyl ether and a C 12 -C 14 alpha olefin in the molar ratio of about 1.0:0.90- 0.99:0.01-0.10. o1 3. A terpolymer according to claim 1 which comprises maleic anhydride, a C 1 -C alkyl vinyl ether and isobutylene in the molar ratio of 1:0.4-0.9:0.1-0.6.

4. A terpolymer according to claim 3 further characterized in having a weight average molecular weight of about 30,000 to 400,000. A terpolymer according to claim 4 further characterized by being in the form of a mixed, partial salt.

6. A terpolymer according to claim 5 still further characterized in being in the form of a mixed, partial calcium/sodium salt wherein the calcium to sodium cation equivalent ratio is 2:1 to 10:1 and has a degree of neutralization of from 0.5 to 0.95 of the total initial carboxyl groups.

7. A terpolymer comprising maleic anhydride, a C 1 -C 5 alkyl vinyl ether and isobutylene or a C 12 -C 14 alpha-olefin, substantially as herein described with reference to r any one of the Examples excluding the comparative Example.

8. A denture adhesive composition, comprising a terpolymer according to any one of claims 1-7 together with a dentally acceptable base carrier. Dated 19 October, 1993 ISP Investments Inc. Patent Attorneys for the Applicant/Nominated Person i SPRUSON FERGUSON "ee ;i IN:\libz]00066:ER 1 of 1