Microencapsulated polyaddition catalyst

Abstract

A microencapsulated polyaddition catalyst comprises a capsule core, containing polyaddition catalyst, and an acrylic copolymer capsule shell, the acrylic copolymer comprising copolymerized units of an intermolecular anhydride of an ethylenically unsaturated C.sub.3-C.sub.12 carboxylic acid. The polyaddition catalyst is selected from acyclic tertiary amines, alicyclic tertiary amines, N-alkylimidazoles, phosphines and organic metal salts. It is suitable for catalysing the reaction of a polyol compound with a polyisocyanate compound. The polyaddition catalyst is released by a chemical stimulus, such as on contact with polyols or water, for example.

Claims

1. A microencapsulated polyaddition catalyst comprising a capsule core, containing the polyaddition catalyst, and an acrylic copolymer capsule shell, the acrylic copolymer comprising copolymerized units of an intermolecular anhydride of an ethylenically unsaturated C.sub.3-C.sub.12 carboxylic acid, and the polyaddition catalyst being selected from acyclic tertiary amines, alicyclic tertiary amines, N-alkylimidazoles, phosphines and organic metal salts.

2. The microencapsulated polyaddition catalyst according to claim 1, wherein the intermolecular anhydride of the ethylenically unsaturated C.sub.3-C.sub.12 carboxylic acid is selected from acrylic anhydride, methacrylic anhydride and 4-vinylbenzoic anhydride.

3. The microencapsulated polyaddition catalyst according to claim 1, wherein the acrylic copolymer is constructed of units of (a) 5 to 50 wt % of at least one intermolecular anhydride of an ethylenically unsaturated C.sub.3-C.sub.12 carboxylic acid, (b) 30 to 90 wt % of at least one monomer selected from C.sub.1-C.sub.24 alkyl esters of acrylic acid, C.sub.1-C.sub.24 alkyl esters of methacrylic acid and vinylaromatics, (c) 5 to 20 wt % of at least one monomer which has at least two ethylenic unsaturations, and (d) 0 to 30 wt % of one or more other monomers, based in each case on the total weight of the monomers.

4. The microencapsulated polyaddition catalyst according to claim 1, wherein the acyclic tertiary amine is selected from triethylamine, tributylamine, N,N-dimethylcyclohexylamine (DMCHA), N-methyldicyclohexylamine, N,N-dimethylbenzylamine (BDMA), N,N-dimethylaminopropylamine, bis(dimethylaminopropyl)amine, N,N-dimethylaminopropyl-N′-methylethanolamine, dimethylaminoethoxyethanol, bis(dimethylaminopropyl)amino-2-propanol, N,N-dimethylam inopropyldipropanolam ine, N, N, N′-trimethyl-N′-hydroxyethyl bisaminoethyl ether, N,N-dimethylaminopropylurea, N,N,N′,N′-tetramethylethylene-diamine, N,N,N′,N′-tetramethylbutylenediamine, N,N,N′,N′-tetramethyl-1,6-hexylenediamine, N,N,N′,N″,N″-pentamethyldiethylenetriamine (PMDETA), N,N,N′,N″,N″-pentamethyldipropylenetriamine (PMDPTA), N,N,N-tris(3-dimethylaminopropyl)amine, bis(2-dimethylaminoethyl) ether (BDMAEE), bis(dimethylaminopropyl)urea, 2,4,6-tris(dimethylaminomethyl)phenol, and also its salt with 2-ethylhexanoic acid and isomers thereof, 1,3,5-tris(3-[dimethyl-amino]propyl)hexahydrotriazine; the alicyclic tertiary amine is selected from 1,4-dimethylpiperazine (DMP), 1-methyl-4-(2-dimethylaminoethyl)piperazine, 1-azabicyclo[3.3.0]octane, 1,4-diazabicyclo[2.2.2]octane (DABCO), 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), 1,5-diazabicyclo[4.3.0]non-7-ene (DBN), N-methylmorpholine, N-ethyl-morpholine, N-cyclohexylmorpholine and 2,2′-dimorpholinodiethyl ether (DMDEE); and the N-alkylimidazole is selected from N-methylimidazole, 1,2-dimethylimidazole, N-(2-hydroxypropyl)imidazole, N-(2-hydroxyethyl)imidazole and N-(2-am inopropyl)-imidazole.

5. The microencapsulated polyaddition catalyst according to claim 1, wherein the organic metal salt has the general formula
L.sub.mM.sup.n+nA.sup.− in which the ligand L is an organic radical or an organic compound selected from alkyl, alkenyl, alkynyl, aryl, arylalkyl, alkylaryl, heteroaryl, heteroarylalkyl, alkylheteroaryl and acyl, the ligand L having 1 to 20 C atoms, and the m ligands L being either identical or different, m is 0, 1, 2, 3, 4, 5 or 6, M is a metal, n is 1, 2, 3 or 4, and the anion A.sup.− is a carboxylate ion, alkoxylate ion or enolate ion.

6. The microencapsulated polyaddition catalyst according to claim 5, wherein the metal M is selected from lithium, potassium, caesium, magnesium, calcium, strontium, barium, boron, aluminum, indium, tin, lead, bismuth, cerium, cobalt, iron, copper, lanthanum, manganese, mercury, scandium, titanium, zinc and zirconium.

7. The microencapsulated polyaddition catalyst according to claim 5, wherein the anion A.sup.− is a carboxylate ion of the formula R.sup.1—COO.sup.−, where R.sup.1 is selected from H, alkyl, alkenyl, alkynyl, aryl, arylalkyl, alkylaryl, heteroaryl, heteroarylalkyl, alkylheteroaryl and acyl, and where the radical R.sup.1 has up to 20 C atoms.

8. The microencapsulated polyaddition catalyst according to claim 5, wherein the anion A.sup.− is an enolate ion of the formula R.sup.2CH═CR.sup.3—O.sup.−, where R.sup.2 and R.sup.3 are each selected from H, alkyl, alkenyl, alkynyl, aryl, arylalkyl, alkylaryl, heteroaryl, heteroarylalkyl, alkylheteroaryl and acyl, and where the radicals R.sup.2 and R.sup.3 each have up to 20 C atoms.

9. The microencapsulated polyaddition catalyst according to claim 1, wherein the capsule core comprises a hydrophobic core material.

10. The microencapsulated polyaddition catalyst according to claim 9, wherein the hydrophobic core material is selected from esters of aliphatic or aromatic polycarboxylic acids, triglycerides and trialkylphosphoric esters.

11. The microencapsulated polyaddition catalyst according to claim 1, wherein the diameter D(0,5) of the microcapsules is between 1 and 50 μm.

12. The microencapsulated polyaddition catalyst according to claim 1, wherein the microencapsulated polyaddition catalyst takes the form of a dry powder, granules or agglomerate.

13. A method for producing a microencapsulated polyaddition catalyst according to claim 1 comprising polymerizing by radical polymerization of a monomer mixture constituting the capsule shell in the oil phase of a stable oil-in-water emulsion, the oil phase containing a polyaddition catalyst, and the monomer mixture containing the intermolecular anhydride of an ethylenically unsaturated C.sub.3-C.sub.12 carboxylic acid.

14. The method according to claim 13, wherein the oil-in-water emulsion is stabilized by a protective colloid and/or a Pickering stabilizer.

15. A method of catalyzing the reaction of a polyol compound with a polyisocyanate compound with a microencapsulated polyaddition catalyst, the microencapsulated polyaddition catalyst comprising a capsule core, containing the polyaddition catalyst, and an acrylic copolymer capsule shell, the acrylic copolymer comprising copolymerized units of an intermolecular anhydride of an ethylenically unsaturated C.sub.3-C.sub.12 carboxylic acid, and the polyaddition catalyst being selected from acyclic tertiary amines, alicyclic tertiary amines, N-alkylimidazoles, phosphines and organic metal salts.

16. The microencapsulated polyaddition catalyst according to claim 6, wherein the anion A.sup.− is a carboxylate ion of the formula R.sup.1—COO.sup.−, where R.sup.1 is selected from H, alkyl, alkenyl, alkynyl, aryl, arylalkyl, alkylaryl, heteroaryl, heteroarylalkyl, alkylheteroaryl and acyl, and where the radical R.sup.1 has up to 20 C atoms.

17. The microencapsulated polyaddition catalyst according to claim 6, wherein the anion A.sup.− is an enolate ion of the formula R.sup.2CH═CR.sup.3—O.sup.−, where R.sup.2 and R.sup.3 are each selected from H, alkyl, alkenyl, alkynyl, aryl, arylalkyl, alkylaryl, heteroaryl, heteroarylalkyl, alkylheteroaryl and acyl, and where the radicals R.sup.2 and R.sup.3 each have up to 20 C atoms.

18. The microencapsulated polyaddition catalyst according to claim 1, wherein the acrylic copolymer is constructed of units of (a) 10 to 30 wt % of at least one intermolecular anhydride of an ethylenically unsaturated C.sub.3-C.sub.12 carboxylic acid, (b) 35 to 80 wt % of at least one monomer selected from C.sub.1-C.sub.24 alkyl esters of acrylic acid, C.sub.1-C.sub.24 alkyl esters of methacrylic acid and vinylaromatics, (c) 10 to 15 wt % of at least one monomer which has at least two ethylenic unsaturations, and (d) 0 to 20 wt % of one or more other monomers, based in each case on the total weight of the monomers.

Description

EXAMPLE 1

(1) Water Phase

(2) 463.15 g of distilled water

(3) 150 g of a 10 wt % aqueous solution of polyvinyl alcohol (Mowiol 18/88 from Kuraray Europe GmbH, viscosity of a 4 wt % solution at 20° C.: 18 mPas as measured to DIN 53015, with a degree of hydrolysis of 88%)

(4) 2 g of a 2.5 wt % aqueous solution of sodium nitrite

(5) 0.12 g of a 25 wt % aqueous solution of sodium hydroxide

(6) Feed 1

(7) 200 g of dibutyltin dilaurate

(8) 200 g of diisononyl cyclohexane-1,2-dicarboxylate

(9) Feed 2

(10) 10 g of 1,4-butanediol diacrylate

(11) 50 g of methyl methacrylate

(12) 40 g of methacrylic anhydride

(13) Feed 3

(14) 2.05 g of tert-butyl peroxyneodecanoate

(15) Feed 4

(16) 10 g of a 10 wt % aqueous solution of tert-butyl hydroperoxide

(17) Feed 5

(18) 26 g of a 3.85 wt % aqueous solution of ascorbic acid

(19) The water phase was introduced into a receiver vessel at 25° C. Feed 1 and feed 2 were added and the mixture was stirred at 3500 rpm for 40 minutes. A stable emulsion was formed. After the addition of feed 3, the following temperature programme was run: heating 75° C. in 180 minutes, holding of this temperature for 60 minutes. Thereafter feed 4 was added, and, in the course of cooling to 20° C., feed 5 was added over a period of 60 minutes.

(20) This gave a dispersion having a solids content of 45.2 wt % with an average particle size D(0,5) of 2.54 μm. The dispersion was subsequently freeze-dried to remove the water. In this case a colourless powder was obtained.

EXAMPLE 2

(21) Example 1 was repeated, but the amounts of the following components were modified as follows:

(22) 70 g of methyl methacrylate

(23) 20 g of methacrylic anhydride

(24) This gave a dispersion having a solids content of 44.8 wt % with an average particle size D(0,5) of 2.25 μm. The dispersion was subsequently freeze-dried to remove the water. In this case a colourless powder was obtained.

EXAMPLE 3

(25) Water phase

(26) 570.7 g of distilled water

(27) 150 g of a 50 wt % aqueous solution of a silica sol having a specific surface area of about 80 m.sup.2/g

(28) 7 g of a 5 wt % aqueous solution of methylhydroxypropylcellulose having an average molecular weight of 26 000 g/mol

(29) 2 g of a 2.5 wt % aqueous solution of sodium nitrite

(30) 3.85 g of a 20 wt % aqueous solution of nitric acid

(31) Feed 1

(32) 200 g of dibutyltin dilaurate

(33) 200 g of diisononyl cyclohexane-1,2-dicarboxylate

(34) Feed 2

(35) 10 g of 1,4-butanediol diacrylate

(36) 50 g of methyl methacrylate

(37) 40 g of methacrylic anhydride

(38) Feed 3

(39) 1.35 g of a 75 wt % solution of tert-butyl perpivalate in aliphatic hydrocarbons

(40) Feed 4

(41) 50 g of a 2 wt % aqueous solution of sodium peroxodisulphate

(42) Feed 5

(43) 14.4 g of a 10 wt % aqueous solution of sodium hydroxide

(44) The water phase was introduced into a receiver vessel at 25° C. Feed 1 and feed 2 were added and the mixture was stirred at 3500 rpm for 40 minutes. A stable emulsion was formed. After the addition of feed 3, the following temperature programme was run: heating to 65° C. in 60 minutes, heating to 90° C. in 60 minutes, holding of this temperature for 150 minutes. In the first 90 minutes of this period, feed 4 was added. After cooling to 20° C., feed 5 was added.

(45) This gave a dispersion having a solids content of 44.6 wt % with an average particle size D(0,5) of 4.00 μm. The dispersion was subsequently freeze-dried to remove the water. In this case a colourless powder was obtained.

EXAMPLE 4

(46) Example 3 was repeated, but the amounts of the following components were modified as follows:

(47) 70 g of methyl methacrylate

(48) 20 g of methacrylic anhydride

(49) 0.73 g of sodium hydroxide

(50) This gave a dispersion having a solids content of 44.7 wt % with an average particle size D(0,5) of 4.16 μm. The dispersion was subsequently freeze-dried to remove the water. In this case a colourless powder was obtained.

EXAMPLE 5

(51) Water Phase

(52) 570.7 g of distilled water

(53) 150 g of a 50 wt % aqueous solution of a silica sol having a specific surface area of about 80 m.sup.2/g

(54) 7 g of a 5 wt % aqueous solution of methylhydroxypropylcellulose having an average molecular weight of 26 000 g/mol

(55) 2 g of a 2.5 wt % aqueous solution of sodium nitrite

(56) 3.85 g of a 20 wt % aqueous solution of nitric acid

(57) Feed 1

(58) 200 g of bismuth neodecanoate

(59) 200 g of diisononyl cyclohexane-1,2-dicarboxylate

(60) Feed 2

(61) 10 g of 1,4-butanediol diacrylate

(62) 70 g of methyl methacrylate

(63) 20 g of methacrylic anhydride

(64) Feed 3

(65) 1.35 g of a 75 wt % solution of tert-butyl perpivalate in aliphatic hydrocarbons

(66) Feed 4

(67) 50 g of a 2 wt % aqueous solution of sodium peroxodisulphate

(68) Feed 5

(69) 0.73 g of a 10 wt % aqueous solution of sodium hydroxide

(70) The method was identical to that stated in experiment 4. This gave a dispersion having a solids content of 42.5 wt % with an average particle size D(0,5) of 3.64 μm. The dispersion was subsequently freeze-dried to remove the water. In this case a colourless powder was obtained.

(71) Examples 1 to 5 were tested with the following procedure:

(72) Test system: a masterbatch was prepared from 91 g (0.5 mol of NCO) of Desmodur N3600 (HDI trimer) and 124 g (0.55 mol of OH) Lupranol 1200 (polypropylene glycol having a number-average molecular weight of 450); 0.15 g of catalyst, or a quantity of microcapsules whose catalyst content corresponds to the free quantity of catalyst, was used for 15 g of masterbatch, corresponding to a catalyst loading of 1% (w/w).

(73) Measurement:

(74) 1) Weighing of suitable quantities of the catalyst into snap-lid glass vessels containing a magnetic stirrer

(75) 2) Production of the masterbatch by mixing the Desmodur N3600 component from Bayer Material Science and the Lupranol 1200 component from BASF under a slow stream of nitrogen for 5 minutes at 400 rpm.

(76) 3) Introducing the mixture into glass sample vessels and carrying out stirring with a magnetic stirrer

(77) 4) Pot life: when magnetic stirrer remains at standstill

(78) 5) Curing time: when the surface of the resin no longer moved when the glass vessel was tipped, the ultimate curing time was ascertained, as soon as the cured resin could no longer be impressed using a spatula.

(79) Test Outcome:

(80) TABLE-US-00001 Pot life/min Curing time/min No catalyst 2880 3000 Pure dibutyltin dilaurate 10 16 catalyst Example 1 75 165 Example 2 270 1080 Example 3 40 75 Example 4 90 270 Pure bismuth 1 1.2 neodecanoate catalyst Example 5 180 265