IL50491A - Polymers and copolymers of esters of methacrylic acid and compositions containing them - Google Patents

Description

-t oniK Hovel polytaejps and copoljraers of esters of methacrylic acid and compositions containing them ROHM D HAAS GOMPAHY 0. 47293 This invention concerns novel polymers and copolymers of esters of methacrylic acid, polymer compositions^ which comprise these novel polymers and methods of using ^ the novel polymers.

Polymers having relatively low molecular weights, often referred to as oligomers, hove recently become of increasing interest, in part due to their use in adhesives, plasticizers , agents, and melt-index improvers, and in formulating coating compositions having very high solids content. While various alkyds, polyesters, poly-ethers, polyamides, and polyurethanes having molecular weights in the range of 500 to 2500 can be conveniently prepared, suitable acrylic polymers in this molecular weight range have heretofore been inaccessible. Because acrylic polymers may have many extremely valuable advantages, including relatively low cost, low color, good outdoor durability, high chemical resistance, and good thermal stability, and because the various non-acrylic low molecular weight polymers with functionali ies greater than two arc often difficult to prepare, polymer compositions comprising low molecular weight acrylic polyme-rs are particularly desirable.

Attempts have been made to prepare acrylic polymers having molecular weight ' distributions in the range of 2500 to 10000 by fre radical polymerization techniques.

However, irt>eS€ procedures are generally unacceptable, either because high temperature or high pressures are \ needed to carry out the polymerisation reaction, because the chain transfer agent employed in the reaction has an objectionable odo or toxicity, or because the properties of the polymer produced in the polyme ization reaction are adversely affected by a high incidence of initiator or chain transfer fragments on the polymer chains.

Furthermore, it is difficult to control the molecular weiqht distribution of polymers prepared by free radical techniques. Thus, such polymers tend to have a broad molecular weight distribution, and contain significant amounts of high molecular weight polymer, which can give unattractive properties to the polymer compositions. We have found that polymer compositions free of the undesirable properties of prior art materials can be prepared by a novel anionic polymerization technique, which allows control of the polymer chain length and of ^ the molecular weight distribution of the polymer. This technique is disclosed and claimed in our copending application 39270 from which the present application is divided. Application 39270 also discloses and claims polymer compositions made by this novel process. We have also found certain novel polymer. compositions wherein the polymer contains certain functional groups.

According to this invention novel polymer compositions are provided which comprise an anionically polymerised methacrylic polymer having an average chain length of 6 to 50 mers and in which at least some of the methacrylic mers are mers of meth- j acrylic acid (or the corresponding anhydride forms of ! such mers) , methacrylic acid chloride or methacrylamide or are of the formula: in which R ' is an aminoalkyl group, optionally substituted on the nitrogen atom with an alk l group, an alkyl group _j having an oxazolidinyl or ketimino substituent, or an isocyanato or sulfonato alkyl group or an hydroxyalkyl group.

Preferred polymers have an average chain length of about 6 to about 25 mers. Generally, at least about 85 % of the molecules of the homopolymer or copolymer in the polymer compositions have chain lengths falling between and 2n, where n is the average chain length of the polymer. Thus, when the average chain length of the homopolymer or copolymer is about 6 mers, at least about 85 % of the molecules of the homopolymer or copolymer generally have chain lengths of about 3 to 12 mers, and whon the average chain length of the homopolymer or copolymer is about 25 mers, at least about 85% of .the molecules of the homopolymer or copolymer qenerally have chain lengths of about 7 to about 50 mers. In a preferred embodiment of the invention, at least about 85% of the molecules of the homopolymer or copolymer in the polymer composition:; will hove a chain length of about 4 to 40 mers. Depending upon the particular ester of rnethacrylic acid which is employed, and the particular comonorner which may be employed, the polymer compositions of the invention will have a molecular weight distribution (weight average molecular weight, Mw) in the range of about 400 to about 10,000, and preferably about 500 to about 2500.

The polymer compositions of the invention may be produced by the anionic homopolymerizotion of an ester of rnethacrylic acid, or by the anionic copolymeriza tion anion, which serves as a catalyst, and an alcohol, which serves as a chain-regulating agent. This process is fully described in our application 39270 which description is hereby incorporated into this specification by reference.

The polymers of the invention, when homopolymers , can generally be represented by the following formula: wherein RO represents the residue of the chain-regulating alcohol used in the polymerization reaction, R'O represents the ester residue in the monomeric ester of methncrylic~ acid.R*" being as above defined, and n is an integer of 3 to 90, preferably 4 to 40, most preferably 5 to 25, a d represents the chuin length of the polymer.

The copolymers of the polymer compositions of the invention can be similarly represented, in general, by the following formula : CH.

RO (— CH„-C I 3 (— M ) ., H (II) 2 J n ' n" COO · wherein RO and R'O are as defined above, M represents the residue of the comonomer or comonomers, and n* and n" are integers of one or more, wherein the sum of n' and n" is 3 to 90, preferably 4 to 40, and most preferably 5 to 25.

It should be noted that the copolymers represented by Formula II re-present polymers of two or more monomers, -copolymers, and does not attempt to show their physical stereochemical structure. Furthermore, it should be. noted that when RO differs from R'O, scrambling of these ~ ί? groups by tri.inr.es terifica ion occurs to some extent during the polymerisation reaction. Thus, in some of the homo-polymers represented by Formula I and copolymers represented by Formula II, RO will be replaced at some positions by R'O and R'O will be replaced at some positions by RO.

Among the esters which can be used in the preparation of the polymers of the invention are those having the formula wherein R' is an aminoalkyl group, preferably having 1 to 8 carbon atoms, and optionally substituted on the nitrogen atom with one alkyl group, preferably having 1 to 4 carbon atoms; or an oxazolidinyl alkyl ■ group or a ketimino alkyl group.

Among the esters embraced by Formula III are aminoalkyl methacrylates, such as aminoethyl methacrylate , methylaminoethyl methacrylate, ethylaminoethyl methacrylate, propylaminoethyl methacrylates, butylaminoethyl methacrylates, hexylaminoethyl methacrylates, ethylaminopropyl methacrylates; oxazolidinylalkyl methacrylates, ketiminoalkyl methacrylates, and the like. Of course, M in Formula II can also represent an alkyl methcrylate, and Formula II embraces copolymers in which two or more esters of methacrylic acid, with or without additional comonomers , have been polymerized, Thus the polymers of the invention can contain, as comonomeric units, units of any one or more non-functional methacrylates, particularly those non-functional methacrylates described A wide variety of monomers can be copolymerized according to the preferred process with esters of acid to form the polymers of this invention, apart from other esters of methacrylic acid. Among the suitable comonomers are methacrylonitrile , vinyl triethoxy silane, diethyl vinyl phosphonate, methyl crotonate, 2-vinylpyridine , and the like. The copolymerization of two or more different esters of methacrylic acid, or of at least one ester of methacrylic acid with another comonomer provides a useful method of incorporating different functional groups into the polymer molecule. For example, the isocyanate functional group can be introduced by copolymerization of at least one alkyl ester of methacrylic acid with at least one aminoalkyl ester of methacrylic acid to provide a copolymer which can be phosgenated to produce the useful isocyanate-containing polymer.

According to the invention polymers having varied or multiple functionality can be produced quite readily. These polymers are especially useful by being capable of undergoing condensation crosslinking reaction. As discussed above, one convenient method is to use as a monomer or comonomer in the polymerization reaction an ester of methacrylic acid or another monomer which itself contains a suitable functional group. Among such monomers are t-butylaminoethyl methacrylate, oxazolidinyl-ethyl methacrylate and isopropyloxazolidinylethyl methacrylate.

Another method for preparing the polymers of the invention is to carry out the polymerization reaction in the presence of an appropriate functional alcohol. Since facile transesterification between the chain-regulating alcohol and the ester methacrylic acid can take place during the . polymerization reaction, the use of a functional - suitable functional a-lcohols which can be thus employed are t-butylaminoethanol acid, N-hydroxyethyloxazolidine .

Still another method for introducing the function¬ ality into the polymers of the invention involves the selective hydrolysis of the ester groups in the polymer to on a-monocarboxylic acid, having the formula · CH-. CH-.

I 3 I 3 HO—(— CH -C -) — CH.-C-H ( IV) I n~1 2 i COOR' COOH wherein RO, R'O and n are as defined above, ; or to an a,6.>-dicarboxylic acid, haying the formula -CH2- ( V) I I COOH COO ' COOH wherein RO, R»0, and n are as defined above.

Using conventional saponification procedures, it has been found thnt hydrolysis of the polymers under alkaline conditions proceeds relatively rapidly to yield selectively a monocarboxylic acid having Formula ,1V...

Continued saponification selectively yields albeit at a much slower rate a dicarboxylic acid having Formula V. Saponification of the residue internal ester groups proceeds, although at a vastly depressed rate, so that selective conversion of the methacrylate polymers to either monocarboxylic or dicarboxylic acids can be accomplished.

Since t e polyme i nation procer,;os of the invention are generally not suitable for the direct ' preparation of acidic polymers by homo- or copolymerization of methacryl i. c acid, these partial hydrolysis products are of particular usefulness and importance. These acids, both in their free acid and salt form, are useful as plasticizers , hot melt coatings, adhesives, leveling agents, coalescent aids, and dispersants. They are also useful as intermediates, representing a convenient source, by means of reaction with ethylene oxide or propylene oxide, of bj.s-hydroxyalkyl esters, which are useful in the preparation of urethanes and isocyanate prepolymers, by means of reaction with dihydroxy alcohols, of polyesters, which are useful in making fibers, coatings, and films, and by means of reaction with epichlorohydrin, of aliphatic bis-opoxides , which are useful in coatings and other plastics applications. Sulfonato ethyl derivatives of the acids, useful in surfactant applications, can also be made · The carboxylic acids of Formulas IV and V can also be readily converted to the corresponding acid chlorides by treatment with known halogenating agents.

Such acid chlorides are useful as intermediates in preparing derivatives of the acids, such as amides and functional esters including t-butylaminoethyl , oxazolidinylethyl , sulfonatoethyl , and similar functional esters. The acid chlorides are also useful in the preparation of various polymers, for use as fibers, coatings, films, and the like.

On heating the polymers of Formula V, at a temperature of about 180 to about 225°C, alcohol is cleaved, (VI) wherein RO, R'O and n are as defined above. Other polymers containing anhydride unctionality are alco produced in this reaction, including various bis- and poly-anhydrides and these are also included in the scope of the invention, Formula VI being intended to represent but one type of such anhydrides.

The conversion of the end groups to anhydride functionality aids in increasing the thermal stability of the polymers, and raises decomposition temperatures of the polymers to greater than 300 °C. The anhydrides, including those having Formula VI, are useful as coatings intermediates and as intermediates in making a wide range of other polymers.

Of course, other derivatives of the polymers of the invention can be conveniently made by post-reactions such as transesterification, saponification and amidation.

The polymer compositions of the invention have a wide variety of uses such as in forming films, coatings, such as in paints, lacquers, varnishes, and the like, powder coatings, impregnants, and adhesives for both natural and synthetic materials, such as paper, textiles, wood, plastics, metal, and leather, as binders for non-woven fabrics, as plasticizers and modifiers for a wide variety of polymer compositions, as melting point depressants, as levelling agents and coalescent aids, and in a wide variety of other uses. Pigments, dyes, fillers, antioxidants, antiozodants , stabilizers, flow controll agents, or other optional ingredients can also be included in the polymer compositions of the invention.

When used as coatings, fillers, or adhesives, the polymer compositions can be applied with or without ' a solvent casting permanently or removably onto a suitable substrate. However, one of the advantages is that reactive polymers can be prepared which can be applied as air-, moisture-, or thermally-cured coatings, fillers or adhesives without the use of any solvents, in either solid or liquid form as 100% solids compositions. This is particularly desirable since elimination of volatile solvent also eliminates potential ecological hazards. o a solvent casting permanently or removably onto a suitable substrate. However, one of the advantages is that reactive polymers can be prepared which can be applied as air-, moisture-, or thermally-cured coatings, fillers or adhesives without the . ise of any solvents, in either solid or liquid form as 100% solids compositions. This is particularly desirable since elimination of volatile solvent also eliminates potential ecological hazards.

The polymers and copolymers of the present invention can be prepared by the methods shown in Example 1 below, which methods form the subject of Patent Specification No. 39270.

Homopolymerization of Methyl Methacrylate Method A This example shows a typical homopoly-merization of an ester of methacrylic acid according to the "batch-type" polymerization process of the invention.

A clean, dry 3-neck flask equipped with mechanical stirrer, condenser and thermometer in a Y-arm side inlet, under dry nitrogen, is charged with commercially pure methyl methacrylate monomer, inhibited with 10 ppm of phenothiazine or dicyclo-hexyl phenylene diamine. The stirred solution is heated; upon warming to 60°C. , it is charged with 0.6 mole % sodium methoxide and 3.0% methanol (added as a 25% by weight solution in methyl alcohol). The cloudy white mixture is heated to 93°C. over a 6-minute period and as the 75-80eC. temperature is passed, methanol addition in aromatic solvent (xylene, toluene) is started via the side arm inlet at the rate of 0.35 mole per minute for a period of 33 minutes (to a total of 15 mole % methyl alcohol addition). The gradually thickening and clearing solution is maintained at 93 - 1 * C. with stirring for an additional two hours. Xylene or toluene are added as diluents as needed for viscosity control. Analysis of the product solution by gas-liquid chromatography upon completion of the reaction time discloses less than 2% of residual methyl methacrylate and a trace 0.1%) of methyl alcohol. Dimer and, trimer levels . are less than 3-4% and less than 8-10% by weight, respectively, as determined by quantitative gas-liquid chromatography and confirmed by gel permeation chromatography. The yellow to yellow-orange mixture is cooled to 60*C, the basic components are quenched with acid (for example, acetic, formic, HC1, H2S04) removing essentially all color, and 1% by weight of a suitable filter aid is dispersed and stirred for 5-10 minutes. Pressure or aspirator filtration results in greater than 94% by weight, recovery of a clear, colorless to light straw solution of methyl methacrylate, polymer. Analysis by gel permeation chromatography shows symmetrical weight distribution around 700-900 M.W., with greater than 85% by weight in the range of 300-1200. Unsaturation determination with solvent-stripped product typically shows less than 0.07 meq./g.

Similar procedures with differing methanol addition rates at constant catalyst level and 3*C. give the product distribution in Table I.

TABLE I Total Alcohol Level (Mole Methanol % of Methyl V Addition Rate Methacrylate Product Appearance and Mole- (Mole %/Min») Charged ) cular Weight Distribution 0.45 20 Oil; 300-900 2 0,30 12-13 Syrup '400-1500 0.20 11 Semi-Solid; 600-1600 0.10 8-9 Brittle Solid M.P.>40eC; 800-3000 0.05 7 Brittle Solid M.P-~ 50-80°; 1000-4000 None 3 Brittle Solid M.P. 50-80e; 1000-10,000 greater than 85% of the product weight contained in the limits specified; by gel permeation chroma tography.

At 80% by weight in solvent.

Method B This example shows a typical homopoly-merization of an ester of methacrylic acid according to a gradual addition polymerization process of the invention.

To the apparatus described in Method A is charged 1.0 to 1.2 mole % (based on monomer to be subsequently added) of powdered potassium tert-butoxide or methoxide to enough toluene or xylene diluent to form a stirrable slurry. A solution of methyl methacrylate containing 15 mole % methanol, neat or about 10% by weight of toluene or xylene for viscosity control, is added dropwise to the stirred . catalyst slurry at 65°C. , at a rate sufficient to maintain reaction (added at 1.3-1.5% per minute for the first half of addition and about 1.0% per minute \ for the second half). The mixture readily takes on a pale yellow color and the viscosity noticeably increases after several percent of the monomer solution is added. Aliquots taken during and following monomer/alcohol addition establish that high conversion polymerization, with molecular weight distribution essentially constant, occurs throughout the addition period, that less than 10% residual monomer remains at the completion of addition. A short holding time at 65eC. reduces monomer levels to about 2%.

Following a 20 to 30 minute hold, the nearly clear, yellow oil is cooled to 60eC.,' quenched with 1.0-1.2% acetic acid (removing almost all color), treated with 1% by weight of a filter aid and vacuum filtered at 60 to 80eC. Gel permeation chromatography of the clear, colorless to light straw colored oil discloses the major weight fraction to be about 1200, with 90% by weight spread between 300 and 2600. Lower methanol levels yielded successively higher molecular weight products (Table II).

Methyl Methacrylate Polymerization, Gradual Addition - Process at 65°C.

Methanol Product M Level (and 90 wt. % distribution) 20% 1100-1200 (300-2500) 16 - 1200 (300-2600) V 12 1600-1700 (350-3500) 10 1800 (350-4000) Method C This example shows a typical homopolymerization of an ester of methacrylic acid according to the two- stage polymerization process of the invention. v To the apparatus described in Method A is charged 2.24 g. (20 mole, 1.0 mole% based on total monomer) of powdered potassium tert-butoxide and about 10 g. xylene to form a stirrable slurry.

Monomer solution a) is prepared with 80 g. (0.80 mole, 40% of total monomer)methyl methacrylate inhib- ited with 3 ppm dicyclohexyl phenylenediamine, and 9.6 g. (0.30 mole, 37.5 mole % of the initial methyl methacrylate charge, 15% of total monomer charge) anhydrous methanol; solution (a) is added over a ! 30 to 45 minute period to the stirred catalyst slurry at 60 to 65 eC. The exotherm observed during the early stages of addition subsides and reaction temperature is maintained throughout addition and for a 45 minute post-addition hold. The reaction mixture is a mobile, hazy orange-yellow from 250 to 1100.

Preparations made with initially soluble sodium methoxide are also successful, and require approximately 4 to 5-fold longer reaction times for 95% conversion 90-93eC, resulting in reaction rates which do not parallel monomer addition rates. Catalyst precipitation occurs with monomer addition and conversion. Gel permeation chromatography discloses a similar ¾"w, at 750-800 with a slightly broader distribution, 300 to 1600.

Examples 2 to :8 .

Preparation of Methacrylate Homopolymers and Copolymers Following the procedures of Example 1, a wide variety of methacrylate homopolymers and copolymers are prepared. Table III summarizes the polymerization conditions and properties of some typical methacrylate polymers of the invention.

TABLE III Methacrylate Homo- and Co-Po Example Monomer(s) Method Conversion (Hours) Alcohol 2 68 MMA/ B C65°) 96 CI.5) 12 32 OXEMA 3 68 MMA/ B (80°) 96 (3)7 12 32 t-BAEMA 4 75 BMA/ B (80°} 95 (2) 12 25 OXEMA 5 78 BMA/ A (93?) 80 C5) 3 22 OXEMA MMA/ B (70°) 90 (4) 8 8 22 (OXEMA)* 7 BMA/ BC70°) 94 8 C4) 128 (OXEMA) 8 8 64 MMA/ B (80°) 93 (2) 12 36 IPOXEMA The following abbreviations are used: MA = methyl methacrylate; BMA = butyl methacrylate; t-BAEMA = t-butyl-aminoethyl methacrylate; OXEMA = 2-oxazolidinylethyl methacrylate; IPOXEMA = 2- (2-isopropyloxazolidinyl) ethyl methacrylate.

A = Method A in Example 1; B = Method B in Example 1; reaction temperature in °C.in parentheses.

Conversion determined by residual monomer via gas liquid chromatography; catalyst is 0.6 mole % NaOCH^ in 3,0 -mole % methanol unless otherwise noted.

Method B, mole % alcohol on monomer Method A, total mole % alcohol on monomer (added at the indicated mole %/min.); Method C, on total monomer, added in first stage.

Weight average molecular weight (Mw> as determined by standardised gel permeation chromatography, based on methyl methacrylate oligomer calibration O 90 wt. % included in the M.W. distribution listed parenthetically); 80% distribution given in several typical examples.

Determined as in footnote 5; The catalyst is 1.0-1.5 mole % powdered potassium t-butoxide .

N(2~hydroxyethyl)oxazolidine used as transesterifying- chain transfer alcohol.

Example .9 Preparation of Mono- and Bls-Carboxylic Acids The following procedure is representative of the preparation sof mono- and bis-carboxylic acids of the v polymers of the invention with known molecular weight distribution.

Ninety grams of the polymeric BMA (96% by of Application 39270 weight in residual BMA monomer) of Example 11/ is taken up in 40 g. isopropanol and warmed to 50° C. To the stirred solution is added dropwise 6,9 g. (87 mmole which includes a calculated excess for the residual monomer) of 50% sodium hydroxide and several grams of water. Within-several minutes the solution clouds as the lower molecular weight salts such as sodium methacrylate and lower acids precipitate. The mixture is stirred at reflux for two hours, cooled and acidified with 90 mmole HC1 in 150 g,. water, taking final pH below 3. The bulk of the cooled aqueous layer is decanted and the remaining oily product is washed with two 50 ml. portions of water and separated. The combined aqueous washings are extracted with two 40 ml. portions of toluene and the toluene extracts added to the product. Azeotropic distillation of residual isopropanol, water and butanol to toluene reflux followed by aspirator filtration of the warm product, gives 82 g. (92% recovery) of a pale yellow, nearly clear oil of 95 wt. % solids in toluene, containing 0.44 meq. CO?H per gram (approximately 7 equiv. percent of total ester functionality).

The bis-acid is prepared similarly, employing approximately twice the level of aqueous sodium hydroxide and a 10 to 12 hour reflux period. Similar work-up gives 76 g.\of a clear, colorless viscous oil of 91 wt. % solids in toluene (83% recovery). Titration shows 1.05 meq. COgH per gram (approximately 16 equiv. % of total ester functionality).

Gel permeation chromatographic analysis of the acid products discloses the molecular weight distributions to be essentially identical with the neutral ester precursors.^ Prolonged reflux (up to 48 hours of reaction mixtures in the presence of excess (40 equiv.%) aqueous sodium hydroxide yields an acidic product only slightly higher (about 20 equiv. %) in acid content than the above bis-acid.

Mono- and bis-acids of (co) polymers of Examples 2 to 8 are similarly prepared.

Example 10 Preparation of Bis- and Poly-Anhydrides A. 17.8 g. of the bis-acid of the polymeric methyl methacrylate of Example 2 of Application 39270 (M^ ca. 750) is warmed under vacuum to 225° C. for 6 hours. The glassy product shows a net loss of 35 equivalent % carboxylic acid by titration and strong anhydride absorption by infrared analysis. methyl methacrylate of Example 2 and 5^eq. % powdered potassium hydroxide are intimately mixed and the melt heated at 225 ° C. under vacuum for 6 hours. Direct titration of the residual 17 g. of hard, glassy product discloses that more than 80 eqivalent % of the carboxylic acid content had been consumed. Methanolysis of the product with excess sodium methoxide in methanol, followed by back titration, indicates 35 eq.% present as reactive anhydride . meric the rapid depolymerization of the neat polyester at 275 ° to 310* C, typical of methyl methacrylate. The bis-acid of the same polymer shows a 7% weight loss between 160° and 200° C. and no further weight loss below 325 eC.

Infrared analysis confirms the formation of the more stable bis- and poly-anhydride cptnpounds.

By the same method bis and polyanhydrides of the compounds of Examples 2 to 8 are obtained.

Example 11 Preparation of Polyisocyanates This example shows the preparation of low molecular weight polyisocyanates by phosgenation of low molecular weight copolymers of tert-butyl aminoethyl methacrylates .

A xylene or chlorobenzene solution containing 100 g. of the MMA/t—BAEMA copolymer of Example 3 is* added dropwise to a saturated solution of phosgene in 50 g. xylene, chlorobenzene , or the like. " Following the addition, the reaction temperature is raised to 125° C, while slow phosgene introduction is maintained for 10 hours. The solution is cooled to 85°, 0.16 g. (one mole %) concentrated HgSO^ is added, and the orange-yellow mixture returned to 125-130°C, with slow nitrogen sweep for 3 hours. The resulting clear amber solution consists of low molecular weight isocyanate copolymer, having 85% conversion of the original amine to reactive isocyanate, and several percent residual ionizable chloride.

The polyisocyanates when formulated and cured with polyols, polyamines, polyoxazolidines , and other active hydrogen compounds form useful coatings, adhesives, films, impregnants for leather and paper, and binders for non-woven fabrics.

Following the above procedures, other secondary amine-containing copolymers of the invention are converted to the corresponding polyisocyanates and have a similar wide variety of uses.

Examples 12 to 15 High Solids Coatings Formulations The following examples show representative high solids, stable, moisture-activated coatings formulated with representative oxazolidine-containing copolymers *of the invention and a typical commercial tri-functional aliphatic isocyanate (such as Desmodur N, believed to be a biuret triisocyanate from hexamethylene dxisocyanate and water) at 1:1 oxazolidine: isocyanate ratios. The moisture-cured systems are generally described in Israeli patent application No. 34305, filed on April 13th 1970.

The properties of several of these coatings formulations are summarized in Table IV.

Table IV Moisture-Cured Coatings Polymer Wt. % of Solids* in Hardness Eq. Swell Ratio Example Example Aromatic Gardner-Holdt (KHN) (DMF) after 7 No. No. Solvent Viscosity (7 Days/25°Cj Day Cure/25 °C. 12 22 76% X 6.9 1.9 13 32 70% P 3.2 1.8 14 27 85% X 5.4 1.7 15 34 70% V 13 1.1 The above formulations give drying and curing rates comparable with coatings formulated with much higher molecular weight C> 20,000) functional components, with practically identical mechanical properties. Such formulations are quite useful in all areas where high polymer systems have been employed, including as coatings for. metal, wood, textiles, and leather, as interior and exterior coatings, as wire "enamels," as adhesives etc.) and at much higher solids contents (75-95% vs. 30-60%).

Similar high solids reactive coatings compositions can be formulated from the other functional copolymers of the invention.

Example 16 Polvol Formation from Low Molecular Weight Methyl Methacrylate Polymer and 1,3-Butylene Glycol Transesterification of 155 g. of a methyl methacrylate polymer prepared according to Example 1, having a Mn of 450, (1.7 moles) 1,3-butylene glycol in the presence of 7 g. (62 mmole, 3.6 eq. %) potassium tert-butoxide at 100°C, employing a slow nitrogen sparge, yielded 22 g. of distillate in 15.5 hours. Another 2.3 g. distillate resulted after 19 hours at 130°C. followed by 0.8 g. distillate after 7 hours at 160°C. The reaction was completed at 200°C. for 16 hours yielding a total of 36 g. distillate. The catalyst was quenched with methanolic HC1; excess methanol and butylene glycol were distilled in vacuo at 150°C./ 7 mm., ending with a nitrogen sparge. The cooled product was taken up in toluene, treated with filter aid and filtered warm. Removal of toluene in vacuo yielded 205 g. of a clear, light yellow solid with . hydroxyl No. 190 and an Mn of 825 (by ebulliometry) .

ExampleJ.7 5 Polyol Formation from Low Molecular Weight Butyl Meth- acrylate Polymer and 1.3-Butylene Glycol Following the procedure of Example 1&, 172 g. of a polymer of butyl methacrylate prepared according to Example 1, having an Mn of 1000, and 77.3 g. (0.86 mole) 1,3-butylene glycol are reacted in the presence of sodium 10 methoxide catalyst at 175 to 200° for 70 hours. Catalyst • neutralization, distillation and filtration, as described o+ ppl aiion 392~70 in Example 44^yielded 173 g. of a light yellow, viscous oil with hydroxyl no. 107 and an Mn of 1265.

Example .18 Polyol Formation from Methy]. Methacrylate Polymer and 1 ,lt-Butylene Glycol ' A flask is charged with 276 g. of methyl methacrylate polymer prepared according to Example 1C, having an M^. of 750 , and 315 g. of Ι,Μ-toutylene glycol. Then 15 ml. ( 66 mmole) of sodium methoxide, 25% solution in methanol, is added to the reaction mixture. The nitrogen flow rate is 85 ml./min. and the reaction mixture is heated to 200°C. Methanol begins to distill at a pot temperature of ^lA0<>C. The distillate is weighed periodically. The reaction mixture is heated at 200°C. for 5 hours. A second charge of catalyst (10 ml., *+3.9 mmole) is made and the reaction mixture heated for another 6 hours at 200°C. At this point, the total weight of the distillate is 79. 6 g. , which is shown by gas liquid chromatographic analysis to contain I .l g. of tetrahydrofuran (THP) or ca. 2 $ of the distillate (excluding the 17. 5 g. of methanol added in the form of sodium methoxide solution and the methanol evolved from reaction The reaction mixture is cooled to 60°C. and 50 g. of methanol added. Anhydrous hydrogen chloride ( . 27 g. , 117-meq.) is then passed through the solution to neutralize the basic species.

The excess hydrogen chloride, methanol and glycol are then removed by distillation at reduced pressure,, ultimately, 200°C. /3 mm. with N2 sparge at 800 ml./min. The precipitated salts are- removed by first diluting the cooled mixture with 150 g. of methyl isobutyl ketone and then filtering. The filtrate is returned to a clean reaction flask and stripped aya.i >i to giv.. light yellow product which at 100$ solids is a solid it room -fceuperature but may be transferred readily at 150°C.

Example i'g Polyol Formation froin Low Mol .·t ( | ¾r Weight Methyl Methacrylate Polymer and Ethyl* .i m Glycol A flask is equipped with a heal ing mantle for temperature regulation, a mechanical stirrer, a nitr>.|-<;ri ebulator, and a condenser atop a Dean-Stark trap. The flask is chi»i.'eed with 580 g. of methyl methacrylate polymer having an of 750 prepared by the method of Example 1C { 79% solids in xylene, ½58 g. up solids, 0.768 mole) and i+28 g. ( 6.91 moles) of ethylene glycol. 'nle mixture is heated at reflux while under a light nitrogen spar>«« (ca. 25 ml./min.) in order to remove water from the system in the w;< l.cr/xylene azeotrope. When the temperature of the distillate reache.-i |. 55-i60°C, the lower layer (ethylene glycol) is no. longer dis.'.-trn no more xylene is seen to distil, the reflux is ended and the r^,otion mixture cooled to 75°C The Dean-Stark trap and conden;;..p are replaced with a distillation head atop a 10" column pack.^i with porcelain saddles. Sodium methoxide ( 25. 5 g. of a 2 % soluti,,,, n methanol, 120 meq.) e ction mixture heat.>,| 0 t o en is obtained and the rate of distillation becomes very slow. The reaction mixture is again cooled to ?5°C. and an additional lh.7 g. (69.I meq.) of sodium methoxide/methanol solution charged. Heating at 190°C. is resumed for an additional 2 hours, during which an additional 28.9 g. of distillate (including 0.1 g. of 2-methoxy ethanol) is collected. The net weight of methanol is 75. g. (2.35 moles).

The reaction mixture is cooled to 100°C. , and 11.1 g. (208 meq.) 1Q# excess of finely divided, solid ammonium chloride was added. The mixture is stirred at 100°C. for 1 hour to ensure complete neutralization. Excess ethylene glycol is then distilled at reduced pressure. During this procedure, ammonia is vigorously evolved from the thermal decomposition of the ammonium carboxylate salt. The crude product is held at the elevated temperature and reduced pressure for 1 hour after the cessation of the distillation to ensure complete decomposition of the ammonium salt.

After the system is cooled to ll+0°C. , the crude product is taken up in 200 g. of xylene and the solution filtered. The filtrate is then returned to a clean flask and heated at reflux at atmospheric pressure (light nitrogen sparge) for 1 hour to remove the last traces of ethylene glycol in the xylene/glycol azeotrope. The xylene solvent is then distilled at reduced pressure, ultimately, 160°C./20 mm. with N≥ sparge of 800 ml./min. for 1 hour to give ^■68 g. of solid product with a hydroxyl number of 201 and an acid number of l8.

Example 20 Polyol Formation from Low. Molecular Weight Butyl Methacryl i be/M hyl Methacrylate Copolymer and Ethylene Gl ycol Following the procedure of Example 19 557 g. of an equi-molar copolymer of butyl methacrylate and methyl methacrylate prepared according to Example 1C, having an Mw of 850 , and 262 g. ( . 23 moles) ethylene glycol are reacted in the presence of sodium methoxi-de catalyst at 130 to 200°C. for 7 hours. Catalyst neutralization, distillation and -filtration, as described in ExamplelB, yielded V78 g. of a yellow, low melting solid with hydroxyl no. 139 , an Mn of 850 and an estimated (by gel permeation chromatography) of 1. 3.

Example .21 Polyurethane Prepolymer Formation with Low Molecular Weight Polyol Intermediates Thirty one grams of butyl methacrylate/butylene glycol polyol of Example 17 is taken up and dissolved with warming in 66 g. toluene. Thirteen grams of isophorone diisocyanate and 0.08 g. dibutyl tin dilaurate catalyst are charged and the solution held at 60eC. for 20 hours. The resulting clear, pale yellow solution is vacuum stripped to 85% solids and contains 1.0 meq. per gram of terminal, nonvolatile isocyanate functionality with a Gardner-Holdt viscosity of E to H.

The prepolymer forms useful adhesive and coatings compositions with appropiate polyols, poly- amines, moisture activated poly-oxazolidines (for example, those of Examples 12-15 * ,masked poly-imines and the like.

Similar compositions are formed when the polyol of Example .16 is substituted in the above compositions, and when other polyols, prepared from polymers of the invention according to the procedure of Examples 16 and 17, are substituted in these compositions.

Example 22 Low molecular weight polymer in acrylic floor polishes ^ The bis-acids of the methyl methacrylate polymers of the invention, prepared according to Example 9 are substituted for rosin acids typically employed in acrylic and polystyrene emulsion, and in acrylic solution floor polish compositions. Gloss, levelling, polish viscosity, recoatability and water resistance are comparable with commercial controls.

Similar floor polish compositions are obtained with the soluble dimethylaminoethy1 methacrylate polymers of the invention, such as those of Examples 15 and.16 and similar polymers having somewhat lower average molecular weight.

Claims (10)

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1. WHAT WE CLAIM IS: homo- or co- , 1» An anionically polymerised methacr lie/polymer having an average chain length of 6 to 50 mers and in which at least some of the methacrylic mers are mers of methacrylie acid (or the corresponding anhydride forms of such mers), methacrylic acid chloride or methacrylamide or are of the formula: in which R* is an aminoalkyl group, optionally substituted on the nitrogen atom with an alkyl group, an alkyl group having an oxazolidinyl or ketimino substituent,, or an isocyanato or sulfonato alkyl group or an hydroxyalkyl group.

2. A polymer as claimed in Claim 1 wherein at least 85% of the molecules have chain lengths from J2n to 2n mers where n represents the average chain length of the polymer.

3. A polymer as claimed in Claim 1 or 2 having an average chain length of 6 to 25 mers.

4. A polymer as claimed in any preceding claim wherein at least some- of the methacrylic mers are mers of methacrylic acid in acid and/or anhydride form,, oxazolidinyl ethyl methacrylate, isopropyloxazolidinylethyl methacrylate, aminoethyl methacrylate, methylaminoeth l methacrylate, ethylaminoethyl me hacr late, propylaminoethyl methacrylate, butylaminoethyl methacrylate, hexylaminoethyl methacrylatjg, ethylaminopropyl methacrylate, sulfonatoethyl methacrylate and/or isocyanatoethyl methacrylate.

5. A polymer as claimed in any preceding claim also containing comonomeric units of one or more to alkyl methacrylates.

6. A polymer as claimed in Claim 5 wherein the co-monomeric units are units of one or more C^ to-C^ alkyl methacrylates.

7. A polymer as claimed in Claim 6 containing methyl methacrylate comonomeric units.

8. A coating composition comprising a polymer of any preceding claim and 0 to 50% of a carrier.

9. A powder coating composition comprising a polymer of any of Claims 1 to 7.

10. An adhesive composition comprising a polymer of any of Claims 1 to 7.. For the DR. REINHOli COiftkANli PARTNERS