POLYMER, PROCESS AND COMPOSITION

Abstract

There is described a low number average molecular weight (M.sub.N<10 kD) and high glass transition temperature (>75 C.) copolymer (optionally a solid grade oligomer (SGO)) that comprises (a) at least 20 wt-% of itaconate functional monomer(s), (b) not more than 40% of a hydrophilic monomer, preferably an acid functional monomer(s) in an amount sufficient to achieve an acid value from 65 to 325 mg KOH per g of solid polymer; (c) optionally not more than 70% of other monomers not being either (a) or (b), having a max content of vinyl aromatic monomer(s) of 40 wt-% and/or max content of methacrylate(s) of 40 wt-%; where the weight percentages of monomers (a), (b) and (c) are calculated as a proportion of the total amount of monomers in the copolymer being 100%.

Claims

1. A process for preparing a copolymer having a low molecular weight and high glass transition temperature, wherein the process comprises conducting a solution polymerisation process of a monomer composition comprising: (a) from 20 to 80 wt-% of at least one itaconate functional monomer not containing acidic groups or precursor acid groups, (b) not more than 40 wt-% of an acid functional monomer in an amount sufficient to achieve an acid value from 160 to 325 mg KOH per g of solid copolymer, and (c) from 0.1 to 40 wt.% of monomers other than monomers (a) or (b); wherein the weight percentages of monomers (a), (b) and (c) total 100% and are calculated as a proportion of the total amount of monomers in the copolymer being 100%; and with the provisos: (I) the copolymer has a number average molecular weight (Mn) of no more than 15 kilograms per mole; and (II) the copolymer has a glass transition temperature of at least 75 C., and (III) the copolymer contains less than 40 wt-% vinyl aromatic monomer; and optionally (IV) the copolymer contains less than 40 wt-% methacrylate monomer.

2. The process as claimed in claim 1, wherein monomer (a) comprises a compound of Formula 1: ##STR00004## where Ra and Rb independently represent any optionally substituted hydrocarbo moiety; and X and Y independently represent O and/or NRc-, where Rc independently in each case represents H and/or any optionally substituted hydrocarbo moiety; with the proviso that Formula 1 does not contain: any acidic group, or any precursor acid group which readily generates an acid group under polymerisation process conditions.

3. The process as claimed in claim 1, wherein monomer (b) is an acid functional monomer or precursor thereof selected form at least one ethylenically unsaturated carboxylic acid and/or derivatives thereof.

4. The process as claimed in claim 3, wherein the monomer composition is substantially free of arylalkylene and/or vinyl aromatic monomers.

5. The process as claimed in claim 1, wherein the copolymer is a solid grade oligomer (SGO).

6. The process as claimed in claim 1, wherein the solution polymerization process comprises the steps of: (i) polymerising monomers (a), (b) and (c) under solution polymerisation process conditions in the presence of solvent, and (ii) removing substantially all the solvent from step (i) to thereby obtain a copolymer comprising at least 95% solids.

Description

EXAMPLE I

[0361] To a round-bottomed flask equipped with a condenser, thermometer, and a stirrer are charged 43 parts of 2-butanone. The reactor contents are heated to 85 C. As soon as the polymerization temperature is reached, a monomer feed consisting of 25 parts of dimethyl itaconate (DMI), 20 parts of styrene (STY), 25 parts of methyl methacrylate (MMA), 30 parts of acrylic acid (AA), and 0.3 parts of azobisisobutyronitrile (AIBN) is fed to the reactor in a period of 270 minutes. At the end of the monomer feed the polymerization temperature is kept at 85 C. for another 60 minutes after which the reactor contents are cooled back to room temperature.

EXAMPLES II TO X

[0362] The Examples II to X are prepared analogously with reference to the method described in Example I above with reference to Table 1 below where the monomer feed in Example I is replaced with those ingredient and in the relative amounts listed in the Table 1.

TABLE-US-00001 TABLE 1 II III IV V VI VII VIII IX X DMI 25 62 55 43 61 55 55 55 55 STY 5 5 MMA 25 3 15 32 9 15 15 20 15 DEI 25 AA 30 30 30 30 iANH 25 25 25 25 MAA 30 AIBN 0.8 0.2 0.6 1.0 0.2 1.2 0.2 0.5 0.2

EXAMPLE XI

[0363] To a high pressure polymerization kid, equipped with a stirrer, thermometer, pressure release valve, and high pressure monomer dosage pump are charged 43 parts of 2-butanone. The reactor contents are heated to 140 C. As soon as the polymerization temperature is reached, a monomer feed consisting of 25 parts of dimethyl itaconate (DMI), 20 parts of styrene (STY), 25 parts of methyl methacrylate (MMA), 30 parts of acrylic acid (AA), and 0.15 parts of di-t-butyl peroxide (DTPO) is fed to the reactor in a period of 270 minutes. At the end of the monomer feed the polymerization temperature is kept at 85 C. for another 60 minutes after which the reactor contents are cooled back to room temperature.

EXAMPLES XII to XX

[0364] The Examples XII to XX may be prepared analogously with reference to the method described in Example XI above with reference to Table 2 below where the monomer feed in Example XI is replaced with those ingredient and in the relative amounts listed in the Table 2.

TABLE-US-00002 TABLE 2 XII XIII XIV XV XVI XVII XVIII XIX XX DMI 25 62 55 43 61 55 55 55 55 STY 5 5 MMA 25 3 15 32 9 15 15 20 15 DEI 25 AA 30 30 30 30 iANH 25 25 25 25 MAA 30 DTPO 0.2 0.4 0.1 0.5 0.1 0.1 0.5 0.1 0.1

EXAMPLE XXI

[0365] To a high pressure polymerization equipment, equipped with a stirrer, thermometer, pressure release valve, and high pressure monomer dosage pump are charged 34 parts of 2-butanone and 9 parts of 2-ethylhexyl alcohol. The reactor contents are heated to 140 C. As soon as the polymerization temperature is reached, a monomer feed consisting of 25 parts of dimethyl itaconate (DMI), 20 parts of styrene (STY), 25 parts of methyl methacrylate (MMA), 30 parts of acrylic acid (AA), and 0.15 parts of di-t-butyl peroxide (DTPO) is fed to the reactor in a period of 270 minutes. At the end of the monomer feed the polymerization temperature is kept at 85 C. for another 60 minutes after which the reactor contents are cooled back to room temperature.

EXAMPLES XXII to XXX

[0366] The Examples XXII to XXX may be prepared analogously with reference to the method described in Example XXII above with reference to Table 3 below where the monomer feed in Example XXX is replaced with those ingredient and in the relative amounts listed in the Table 3.

TABLE-US-00003 TABLE 3 XXII XXIII XXIV XXV XXVI XXVII XXVIII XXIX XXX DMI 25 62 55 43 61 55 55 55 55 STY 5 5 MMA 25 3 15 32 9 15 15 20 15 DEI 25 AA 30 30 30 30 iANH 25 25 25 25 MAA 30 DTPO 0.2 0.4 0.1 0.5 0.1 0.1 0.5 0.1 0.1

EXAMPLES XXXI to XXXVI

[0367] The Examples XXXI to XXXVI may be prepared analogously with reference to the methods described herein above with reference to Table 4 below where the monomer feed may consists of the ingredients and the relative amounts listed in Table 4.

TABLE-US-00004 TABLE 4 XXXI XXXII XXXIII XXXIV XXXV XXXVI DMI 55 55 55 30 30 30 DBI 20 MMA 60 60 60 AA 15 15 15 10 DAAM 10 10 10 BA 20 IA 10 IANH 10 PEG350 20 Tg ( C.) 37.2 49.4 74.0 101.8 105.9 104.1

EXAMPLES XXXVII to XLIV

[0368] The following Examples XXXVII to XLIV were prepared as described below and some of their properties results are given in Table 5.

EXAMPLE XXXVII MMA/DMI/AA

[0369] To a round-bottomed flask equipped with a condenser, thermometer, and a stirrer are charged 394.0 parts of 2-butanone. The reactor contents are heated to 80 C. As soon as the polymerization temperature is reached, 13.3 parts of azobis(2-methyl butyronitrile) are added and the monomer feed and catalyst feed are started. The monomer feed consists of 244.4 parts of methyl methacrylate, 244.4 parts of dimethyl itaconate, and 244.4 parts of acrylic acid. The catalyst feed consists of 31.1 parts of azobis(2-methyl butyronitrile) dissolved in 125.9 parts of 2-butanone. Both feeds are added over a period of 180 minutes.

[0370] At the end of the feeds 2.5 parts of azobis(2-methyl butyronitrile) are added and the mixture is stirred at 80 C. for another 150 minutes. The mixture is cooled to room temperature.

[0371] To 615.8 parts of the polymer solution is added a mixture of 99.6 parts of a 25 wt-% of ammonia in water, and 1080.5 parts of water. Next, the 2-butanone is removed at 50 C. under reduced pressure. The solids content is corrected to 22.5% using demineralized water and the pH is corrected to 8.6-8.8 using a 25 wt-% solution of ammonia in water.

[0372] The final polymer solution has a solids content of 22.5% and a pH of 8.7.

EXAMPLE XXXVII S/DMI/AA

[0373] To a round-bottomed flask equipped with a condenser, thermometer, and a stirrer are charged 394.0 parts of 2-butanone. The reactor contents are heated to 80 C. As soon as the polymerization temperature is reached, 13.3 parts of azobis(2-methyl butyronitrile) are added and the monomer feed and catalyst feed are started. The monomer feed consists of 244.4 parts of styrene, 244.4 parts of dimethyl itaconate, and 244.4 parts of acrylic acid. The catalyst feed consists of 31.1 parts of azobis(2-methyl butyronitrile) dissolved in 125.9 parts of 2-butanone. Both feeds are added over a period of 180 minutes.

[0374] At the end of the feeds 2.5 parts of azobis(2-methyl butyronitrile) are added and the mixture is stirred at 80 C. for another 150 minutes. The mixture is cooled to room temperature.

[0375] To 546.1 parts of polymer solution is added a mixture of 105.4 parts of a 25 wt-% of ammonia in water, and 1144.1 parts of water. Next, the 2-butanone is removed at 50 C. under reduced pressure. The solids content is corrected to 22.5 A using demineralized water and the pH is corrected to 8.6-8.8 using a 25 wt-% solution of ammonia in water.

[0376] The final polymer solution has a solids content of 22.4% and a pH of 8.6.

EXAMPLE XXXIX MMA/DMI/AA

[0377] To a high pressure reactor equipped with a thermometer, and a stirrer are charged 500.0 parts of 2-butanone. The reactor contents are heated to 140 C. As soon as the polymerization temperature is reached, 2.9 parts of di-t-butyl peroxide and 40 parts of 2-butanone are added. 5 minutes later the monomer feed is started. The monomer feed consists of 331.8 parts of methyl methacrylate, 331.8 parts of dimethyl itaconate, 331.8 parts of acrylic acid, 5.7 parts of di-t-butyl peroxide, and 6.6 parts of t-butyl perbenzoate, and is added over a period of 180 minutes at 140 C.

[0378] At the end of the feed the feed tank is rinsed with 90.9 parts of 2-butanone. 45 minutes after completion of the monomer feed 2.5 parts of t-butyl perbenzoate dissolved in 40 parts of 2-butanone are added and the mixture is stirred at 140 C. for another 45 minutes. Next, 2.5 parts of t-butyl perbenzoate dissolved in 40 parts of 2-butanone are added and the mixture is stirred for another 135 minutes at 140 C.

[0379] The mixture is cooled to room temperature.

[0380] To 619.3 parts of the polymer solution is added a mixture of 99.3 parts of a 25 wt-% of ammonia in water, and 1077.3 parts of water. Next, the 2-butanone is removed at 50 C. under reduced pressure. The solids content is corrected to 22.5% using demineralized water and the pH is corrected to 8.6-8.8 using a 25 wt-% solution of ammonia in water.

The final polymer solution has a solids content of 22.5% and a pH of 8.6.

EXAMPLE XL S/DMI/AA

[0381] To a high pressure reactor equipped with a thermometer, and a stirrer are charged 500.0 parts of 2-butanone. The reactor contents are heated to 140 C. As soon as the polymerization temperature is reached, 4.4 parts of di-t-butyl peroxide and 40 parts of 2-butanone are added. 5 minutes later the monomer feed is started. The monomer feed consists of 331.8 parts of styrene, 331.8 parts of dimethyl itaconate, 331.8 parts of acrylic acid, 8.6 parts of di-t-butyl peroxide, and 10.0 parts of t-butyl perbenzoate, and is added over a period of 180 minutes at 140 C.

[0382] At the end of the feed the feed tank is rinsed with 90.9 parts of 2-butanone. 45 minutes after completion of the monomer feed 2.5 parts of t-butyl perbenzoate dissolved in 40 parts of 2-butanone are added and the mixture is stirred at 140 C. for another 45 minutes. Next, 2.5 parts of t-butyl perbenzoate dissolved in 40 parts of 2-butanone are added and the mixture is stirred for another 135 minutes at 140 C. The mixture is cooled to room temperature.

[0383] To 617.8 parts of the polymer solution is added a mixture of 99.4 parts of a 25 wt-% of ammonia in water, and 1078.6 parts of water. Next, the 2-butanone is removed at 50 C. under reduced pressure. The solids content is corrected to 22.5% using demineralized water and the pH is corrected to 8.6-8.8 using a 25 wt-% solution of ammonia in water.

[0384] The final polymer solution has a solids content of 22.5% and a pH of 8.7.

EXAMPLE XLI

Sequential Polymerization Using the Polymer from Example XXXVII

[0385] To a round-bottomed flask equipped with a condenser, thermometer, and a stirrer are charged 128.9 parts of the alkaline solution obtained from Example XXXVII. The mixture is heated to 80 C.2 C.

[0386] As soon as the reaction temperature is reached, a mixture of 0.2 parts of sodium persulphate and 0.4 parts of demineralized water is added. After 5 minutes, the monomer feed, consisting of 43.8 parts of methyl methacrylate and 43.8 parts of butyl acrylate, and the initiator feed, consisting of 10.8 parts of demineralized water and 0.4 parts of sodium persulphate (corrected to a pH of 8 using a 25 wt-% ammonia solution) are started. Both feeds should take 120 minutes. At the end of the monomer feed, the feed tank is rinsed with 1.2 parts of water. After both feeds are completed, the batch is stirred at 80 C. for another 30 minutes, after which it is cooled to 50 C.

[0387] At 50 C., one third of a mixture consisting of 0.1 part of a 70 wt-% solution of t-butyl hydroperoxide is added followed by one third of a solution of 0.1 part of iso-ascorbic acid in 2.9 parts of water. 15 minutes later and 30 minutes later similar portions are added and the batch is stirred at 50 C. for another 15 minutes.

[0388] The pH is checked and, if necessary, adjusted to 8.40.1 using a 25 wt-% solution of ammonia in water. The batch is cooled to room temperature, after which the solids content is adjusted to 48.5%1% using demineralized water.

EXAMPLE XLII

Sequential Polymerization Using the Polymer from Example XXXVIII

[0389] A polymer was prepared analogous to the method described in Example XLI, using the alkaline solution obtained from Example XXXVIII. The final emulsion was highly viscous, requiring a dilution to a solids content of 35%.

Example XLIII

Sequential Polymerization Using the Polymer from Example XXXIX

[0390] A polymer was prepared analogous to the method described in Example XLI, using the alkaline solution obtained from Example XXXIX.

EXAMPLE XLIV

Sequential Polymerization Using the Polymer from Example XL

[0391] A polymer was prepared analogous to the method described in Example XLI, using the alkaline solution obtained from Example XL.

TABLE-US-00005 TABLE 5 Results SC (%) Viscosity (mPa .Math. s) pH Example XLI 47.6 208 8.4 Example XLII 34.8 1006 8.4 Example XLIII 48.1 35 8.5 Example XLIV 48.1 201 8.4