Fatty acid vinyl ester copolymers with wax qualities

Abstract

Subject-matter of the invention are processes for preparing fatty acid vinyl ester copolymers by radically initiated polymerization of a) one or more vinyl esters of carboxylic acids having 16 to 22 carbon atoms and b) one or more vinyl esters of carboxylic acids having 2 to 15 carbon atoms, with one or more vinyl esters a) and one or more vinyl esters b) being metered in during the polymerization, characterized in that during the polymerization either the metering rate of vinyl ester a) or the metering rate of vinyl ester b) is reduced and the metering rate of the other of the two vinyl esters, a) or b), is increased.

Claims

1. A method for preparing fatty acid vinyl ester copolymers by free-radical initiated polymerization of a) one or more vinyl esters of carboxylic acids having 16 to 22 carbon atoms and b) one or more vinyl esters of carboxylic acids having 2 to 15 carbon atoms, wherein the one or more vinyl esters a) and the one or more vinyl esters b) are metered in during the polymerization, and during the polymerization either a metered addition rate of vinyl ester a) or a metered addition rate of vinyl ester b) is reduced and the metered addition rate of the other of the two vinyl esters a) or b) is increased.

2. The method for preparing fatty acid vinyl ester copolymers as claimed in claim 1, wherein the one or more vinyl esters a) are vinyl esters of carboxylic acids selected from the group consisting of palmitic acid, stearic acid, margaric acid, arachidic acid and behenic acid and/or the one or more vinyl esters b) are members selected from the group consisting of vinyl acetate, vinyl propionate, vinyl butyrate, 1-methylvinyl acetate, vinyl pivalate, vinyl laurate, vinyl neodecanoate and vinyl esters of -branched monocarboxylic acids having 9 to 11 carbon atoms.

3. The method for preparing fatty acid vinyl ester copolymers as claimed in claim 1, wherein the vinyl esters a) are used from 20 to 90% by weight and/or the vinyl esters b) are used from 10 to 80% by weight, based in each case on a total mass of a sum total of ethylenically unsaturated monomers used for preparing the fatty acid vinyl ester copolymers.

4. The method for preparing fatty acid vinyl ester copolymers as claimed in claim 1, wherein the metered addition of the vinyl esters a) and/or vinyl esters b) is carried out continuously.

5. The method for preparing fatty acid vinyl ester copolymers as claimed in claim 1, wherein 15 to 50% by weight of a total vinyl esters V1) used have been metered in up to a time point at which 1 to 10% of a total vinyl esters V2) used have been metered in; and/or 30 to 70% by weight of the total vinyl esters V1) used have been metered in up to a time point at which 20 to 30% by weight of the total vinyl esters V2) used have been metered in; and/or 40 to 80% by weight of the total vinyl esters V1) used have been metered in up to a time point at which 40 to 60% by weight of the total vinyl esters V2) used have been metered in; and/or 50 to 80% by weight of the total vinyl esters V1) used have been metered in up to a time point at which 60 to 70% by weight of the total vinyl esters V2) used have been metered in, wherein vinyl ester V1 is the vinyl ester a) or b) whose metered addition rate is reduced during the polymerization, and vinyl ester V2 is the vinyl ester a) or b) whose metered addition rate is increased during the polymerization.

6. The method for preparing fatty acid vinyl ester copolymers as claimed in claim 1, wherein 70 to 100% by weight of a total vinyl esters V1) used are metered in while vinyl esters V2) are metered in, and/or 80 to 100% by weight of a total vinyl esters V2) used are metered in while vinyl esters V1) are metered in, wherein vinyl ester V1 is the vinyl ester a) or b) whose metered addition rate is reduced during the polymerization, and vinyl ester V2 is the vinyl ester a) or b) whose metered addition rate is increased during the polymerization.

7. The method for preparing fatty acid vinyl ester copolymers as claimed in claim 5, wherein vinyl ester V1) is the vinyl ester a) and vinyl ester V2) is the vinyl ester b).

8. A fatty acid vinyl ester copolymer obtained by free-radical initiated polymerization of a) one or more vinyl esters of carboxylic acids having 16 to 22 carbon atoms and b) one or more vinyl esters of carboxylic acids having 2 to 15 carbon atoms, wherein: (i) the one or more vinyl esters a) and the one or more vinyl esters b) are metered in during the polymerization; (ii) during the polymerization either a metered addition rate of vinyl esters a) or a metered addition rate of vinyl esters b) is reduced and the metered addition rate of the other of the two vinyl esters a) or b) is increased; (iii) 15 to 50% by weight of total vinyl esters V1) used are metered in up to a time point at which 1 to 10% of total vinyl esters V2) used are metered in; and/or 30 to 70% by weight of the total vinyl esters V1) used are metered in up to a time point at which 20 to 30% by weight of the total vinyl esters V2) used are metered in; (iv) the one or more vinyl esters a) or b), whose metered addition rate is reduced during the polymerization, is referred to as vinyl ester V1) and the one or more vinyl esters a) or b), whose metered addition rate is increased during the polymerization, is referred to as vinyl ester V2); and (v) the fatty acid vinyl ester copolymer is a gradient polymer comprising a gradient in a distribution of units of vinyl esters a) and vinyl esters b) along a polymer chain thereof.

9. The fatty acid vinyl ester copolymer as claimed in claim 8, wherein a melting point and an enthalpy of fusion of the fatty acid vinyl ester copolymer meet one or more of the following criteria: a) 5% to 35% of the enthalpy of fusion is in a range from 2 C. below the melting point to 2 C. above the melting point; b) 10% to 70% of the enthalpy of fusion is in a range from 4 C. below the melting point to 4 C. above the melting point; c) 30% to 85% of the enthalpy of fusion is in a range from 8 C. below the melting point to 8 C. above the melting point; where the melting point and the enthalpy of fusion are determined according to DIN EN ISO 11357-3.

10. The fatty acid vinyl ester copolymer as claimed in claim 8, wherein a melting point and an enthalpy of fusion of the fatty acid vinyl ester copolymer meet one or more of the following criteria: a) 95% to 65% of the enthalpy of fusion of the fatty acid vinyl ester copolymers are in a temperature range which deviates by more than 2 C. from the melting point of the fatty acid vinyl ester copolymers; b) 90% to 30% of the enthalpy of fusion of the fatty acid vinyl ester copolymers are in a temperature range which deviates by more than 4 C. from the melting point of the fatty acid vinyl ester copolymers; c) 70% to 15% of the enthalpy of fusion of the fatty acid vinyl ester copolymers are in a temperature range which deviates by more than 8 C. from the melting point of the fatty acid vinyl ester copolymers; where the melting point and the enthalpy of fusion are determined according to DIN EN ISO 11357-3.

11. Fatty acid vinyl ester copolymer compositions based on fatty acid vinyl ester copolymers as claimed in claim 8, with the proviso that 30% by weight, based on a dry weight of the fatty acid vinyl ester copolymer composition, of the fatty acid vinyl ester copolymers are present, which are based on 90% by weight of vinyl esters a), based on a weight of the fatty acid vinyl ester copolymers.

12. A coating method comprising coating a material with the fatty acid vinyl ester copolymer of claim 8.

13. A preparation method comprising using the fatty acid vinyl ester copolymer of claim 8 as an additive for cosmetic or pharmaceutical products, for paper coating compositions, as a wax substitute in chewing gum raw materials or as a lubricant, a thickener, or for hydrophobizing surfaces.

14. The method for preparing fatty acid vinyl ester copolymers as claimed in claim 2, wherein the vinyl esters a) are used from 20 to 90% by weight and/or the vinyl esters b) are used from 10 to 80% by weight, based in each case on a total mass of a sum total of ethylenically unsaturated monomers used for preparing the fatty acid vinyl ester copolymers.

15. The method for preparing fatty acid vinyl ester copolymers as claimed in claim 14, wherein the metered addition of the vinyl esters a) and/or vinyl esters b) is carried out continuously.

16. The method for preparing fatty acid vinyl ester copolymers as claimed in claim 15, wherein 15 to 50% by weight of a total vinyl esters V1) used have been metered in up to a time point at which 1 to 10% of a total vinyl esters V2) used have been metered in; and/or 30 to 70% by weight of the total vinyl esters V1) used have been metered in up to a time point at which 20 to 30% by weight of the total vinyl esters V2) used have been metered in; and/or 40 to 80% by weight of the total vinyl esters V1) used have been metered in up to a time point at which 40 to 60% by weight of the total vinyl esters V2) used have been metered in; and/or 50 to 80% by weight of the total vinyl esters V1) used have been metered in up to a time point at which 60 to 70% by weight of the total vinyl esters V2) used have been metered in, wherein vinyl ester V1 is the vinyl ester a) or b) whose metered addition rate is reduced during the polymerization, and vinyl ester V2 is the vinyl ester a) or b) whose metered addition rate is increased during the polymerization.

17. The method for preparing fatty acid vinyl ester copolymers as claimed in claim 16, wherein 70 to 100% by weight of a total vinyl esters V1) used are metered in while vinyl esters V2) are metered in, and/or 80 to 100% by weight of a total vinyl esters V2) used are metered in while vinyl esters V1) are metered in.

18. The method for preparing fatty acid vinyl ester copolymers as claimed in claim 17, wherein vinyl ester V1) is the vinyl ester a) and vinyl ester V2) is the vinyl ester b).

Description

EXAMPLE 1 (EX. 1)

(1) Preparation of metered addition 1 (vinyl stearate solution): 150.0 g of vinyl stearate were placed in a 250 ml Schlenk flask, melted at 50 C. and degassed for 15 minutes under reduced pressure (2.310.sup.1 mbar). 60 g of isopropanol were added under an argon atmosphere.

(2) Preparation of metered addition 2 (vinyl laurate solution): 100.0 g of vinyl laurate were placed in a further 250 ml Schlenk flask and degassed at room temperature for 15 minutes under reduced pressure (2.310.sup.1 mbar). 60 g of isopropanol were added under an argon atmosphere.

(3) Preparation of metered addition 3 (initiator solution): In a 100 ml Schlenk flask were placed 60 g of isopropanol and 3.2 g of tert-butyl peroxypivalate (75% aqueous solution) under an argon countercurrent.

(4) Performance of the Polymerization:

(5) A 1000 ml five-necked flask was heated to 80 C. and into this was placed under an argon atmosphere 40.0 g of isopropanol and 0.8 g of tert-butyl peroxypivalate solution (75% aqueous solution) (initial charge).

(6) After 2 minutes, metered additions 1, 2 and 3 were simultaneously started.

(7) The initiator solution (metered addition 3) was added continuously at a metering rate of 0.5 g/min over 2 hours using an Ismatec IPC peristaltic pump.

(8) The vinyl stearate solution (metered addition 1) was added with decreasing rate using an Ismatec peristaltic pump and the tubing was temperature controlled at 40 C. under a 250 W IR lamp. The metered addition 1 was added according to the following metering scheme: initially at 4.4 g/min for 10 min, then 3.6 g/min for 10 min, then 2.8 g/min for 10 min, then 2.4 g/min for 10 min and finally 1.0 g/min for 80 min.

(9) The vinyl laurate solution (metered addition 2) was added via a peristaltic pump with increasing rate. The metered addition 2 was added according to the following metering scheme: initially at 1.6 g/min for 10 min, then 2.4 g/min for 10 min, then 2.8 g/min for 10 min, then 3.6 g/min for 10 min and finally 4.4 g/min for 13 min.

(10) Subsequently, the solvent was removed under reduced pressure (2.310.sup.1 mbar). This gave the fatty acid vinyl ester copolymer in the form of a colorless solid (residual monomer content <1%).

(11) Analytical Data:

(12) Molecular weight: Mn=3300 g/mol; Mw=6600 g/mol.

(13) DSC: Melting temperature: 30.7 C., enthalpy of fusion 51.7 J/g (lower peak limit: 8.4 C., upper peak limit: 44.5 C.)

(14) Enthalpy of fusion in the temperature range of +/2 C. of the melting temperature: 9.5 J/g, which corresponds to 19% of the enthalpy of fusion of the whole melting peak. The expression +/2 C. of the melting temperature refers to the range of 2 C. below the melting temperature to 2 C. above the melting temperature and is used analogously below.

(15) Enthalpy of fusion in the temperature range of +/4 C. of the melting temperature: 18.3 J/g, which corresponds to 35% of the enthalpy of fusion of the whole melting peak.

(16) Enthalpy of fusion in the temperature range of +/8 C. of the melting temperature: 31.6 J/g, which corresponds to 61% of the enthalpy of fusion of the whole melting peak.

(17) Needle Penetration Measurement:

(18) at sample specimen temperature of 22 C.: 7.8 mm;

(19) at sample specimen temperature of 10 C.: 3.0 mm.

(20) Congealing point: 43 C.

(21) Glass coating: homogeneous coating.

(22) Cheese Coating:

(23) homogeneous coating, low temperature sensitivity. Not sticky when handled manually.

(24) No brittleness, no surface stickiness.

COMPARATIVE EXAMPLE 2 (C.EX. 2): RANDOM COPOLYMER

(25) 40 g of vinyl laurate and 60 g of vinyl stearate were initially charged in a 250 ml three-necked flask. The monomer mixture was heated to 50 C. and degassed for 15 min under reduced pressure (2.310.sup.1 mbar). 25 g of isopropanol and 0.3 g of tert-butyl peroxypivalate solution (75% solution in water) were added under an argon countercurrent. The mixture was heated (under reflux conditions) to 80 C. On reaching 80 C., a further 25 g of isopropanol together with 0.570 g of tert-butyl peroxypivalate were added dropwise via a 50 ml dropping funnel over 30 minutes. The reaction mixture was subsequently maintained at 80 C. for 2 h.

(26) Subsequently, the solvent isopropanol was removed under reduced pressure (2.310.sup.1 mbar) and 95 C.

(27) This gave a random copolymer in the form of a colorless solid (residual monomer content <1%).

(28) Analytical Data:

(29) Molecular weight: Mn=10 719 g/mol; Mw=27 874 g/mol.

(30) DSC: Melting temperature: 28.5 C., enthalpy of fusion 46.4 J/g (lower peak limit: 1.3 C., upper peak limit: 38.0 C.)

(31) Enthalpy of fusion in the temperature range of +/2 C. of the melting temperature: 18.1 J/g, which corresponds to 39% of the enthalpy of fusion of the whole melting peak.

(32) Enthalpy of fusion in the temperature range of +/4 C. of the melting temperature: 30.3 J/g, which corresponds to 65% of the enthalpy of fusion of the whole melting peak.

(33) Enthalpy of fusion in the temperature range of +/8 C. of the melting temperature: 39.8 J/g, which corresponds to 85.8% of the enthalpy of fusion of the whole melting peak.

(34) Needle Penetration Measurement:

(35) at sample specimen temperature of 22 C.: 6.5 mm;

(36) at sample specimen temperature of 10 C.: 1.5 mm.

(37) Congealing point: 36 C.

(38) Glass coating: homogeneous coating.

(39) Cheese Coating:

(40) homogeneous coating but very temperature sensitive; was very sticky on manual handling (considerable portions melt at hand temperature).

(41) At identical monomer composition as example 1, comparative example 2 has a distinctly narrower melting range. 65% of the total enthalpy of fusion was in a temperature window of +/4 C., whereas in example 1 only 35% of the enthalpy of fusion was in a temperature window of +/4 C. The product of comparative example 2 was harder at room temperature and therefore more brittle and reacted significantly more sensitively to temperature changes (the melting/crystallization process was in a narrow temperature range). For instance, on lowering the temperature it was very brittle (see needle penetration measurement at 10 C.: 1.5 mm) and on increasing the temperature it abruptly formed sticky surfaces and was liquid on further increasing the temperature (congealing temperature 36 C.)

COMPARATIVE EXAMPLE 3 (C.EX. 3)

(42) polymer mixing of 40% by weight vinyl laurate homopolymer and 60% by weight vinyl stearate homopolymer.

(43) Preparation of Vinyl Laurate Homopolymer:

(44) 100 g of vinyl laurate were initially charged in a 250 ml three-necked flask, heated to 50 C. and degassed under reduced pressure (2.310.sup.1 mbar) for 15 minutes. Then, 25 g of isopropanol and 0.3 g of tert-butyl peroxypivalate (75% solution in water) were added in one shot under an argon countercurrent. The mixture was heated (reflux) to a reaction temperature of 80 C. On reaching 80 C., a further 25 g of isopropanol together with 0.7 g of tert-butyl peroxypivalate were added dropwise via a 50 ml dropping funnel over 45 minutes. The reaction mixture was subsequently maintained at 80 C. for 2 h. Subsequently, the isopropanol solvent was removed under reduced pressure (2.310.sup.1 mbar) and 95 C. This gave a cloudy, highly viscous liquid (residual monomer content <1%).

(45) Molecular weight: Mn=12 828 g/mol; Mw=32 280 g/mol.

(46) Preparation of the Vinyl Stearate Homopolymer:

(47) 100 g of vinyl stearate were initially charged in a 250 ml three-necked flask, heated to 50 C. and degassed under reduced pressure (2.310.sup.1 mbar) for 15 minutes. Then, 25 g of isopropanol and 0.28 g of tert-butyl peroxypivalate (75% solution in water) were added in one shot under an argon countercurrent. The mixture was heated (reflux) to a reaction temperature of 80 C. On reaching 80 C., a further 25 g of isopropanol together with 0.45 g of tert-butyl peroxypivalate were added dropwise via a 50 ml dropping funnel over 30 minutes. The reaction mixture was subsequently maintained at 80 C. for 2 h. Subsequently, the isopropanol solvent was removed under reduced pressure (2.310.sup.1 mbar) and 95 C. This gave a colorless solid.

(48) Molecular weight: Mn=15 170 g/mol; Mw=29 427 g/mol.

(49) Mixing of the Two Homopolymers:

(50) 20 g of the vinyl laurate homopolymer described above and 30 g of the vinyl stearate homopolymer described above were weighed into a 50 ml glass vial and mixed homogeneously as melts by stirring at 60 C.

(51) DSC: melt diagram: two baseline separated melt regions, two melt peaks:

(52) melt peak 1:

(53) melting temperature: 53.6 C., enthalpy of fusion: 53.0 J/g (lower peak limit 11.6 C., upper peak limit 61.8 C.);

(54) melt peak 2:

(55) melting temperature: 2.56 C., enthalpy of fusion: 10.7 J/g.

(56) Enthalpy of fusion in the temperature range of +/2 C. of the melting temperature: 33.5 J/g, which corresponds to 62% of the enthalpy of fusion of the whole melting peak.

(57) Enthalpy of fusion in the temperature range of +/4 C. of the melting temperature: 41.8 J/g, which corresponds to 78% of the enthalpy of fusion of the whole melting peak.

(58) Enthalpy of fusion in the temperature range of +/8 C. of the melting temperature: 47.7 J/g, which corresponds to 89.0% of the enthalpy of fusion of the whole melting peak.

(59) Needle Penetration Measurement:

(60) at sample specimen temperature of 22 C.; 3.9 mm;

(61) at sample specimen temperature of 10 C.: 3.4 mm.

(62) Glass coating: crack formation.

(63) Cheese coating: crack formation.

(64) The coatings were fragile, brittle and also have a high surface stickiness. In addition, the different constituents of the coatings were incompatible with one another.

COMPARATIVE EXAMPLE 4 (C.EX. 4): TWO-STAGE HOMOPOLYMERIZATION

(65) 100 g of vinyl stearate were initially charged in a 500 ml three-necked flask, heated to 50 C. and degassed under reduced pressure (2.310.sup.1 mbar) for 15 minutes. Then, 0.28 g of tert-butyl peroxypivolate (75% solution in water) were added in one shot under an argon countercurrent. The mixture was heated (reflux) to a reaction temperature of 80 C. On reaching 80 C., a further 0.45 g of tert-butyl peroxypivalate were added dropwise over 30 minutes. On reaching a residual monomer content of 10% (amount of vinyl stearate corresponded to 10% of the starting value), 40 g of degassed vinyl laurate were added in one shot under an argon atmosphere. Tert-butyl peroxypivalate was replenished until the residual monomer content was less than 1%. This gave a colorless solid.

(66) DSC: melt diagram: two baseline separated melt regions, two melt peaks:

(67) melt peak 1:

(68) melting temperature: 51.6 C., enthalpy of fusion: 44.1 J/g (lower peak limit 20.7 C., upper peak limit 58.6 C.);

(69) melt peak 2:

(70) melting temperature: 1.3 C., enthalpy of fusion: 9.5 J/g.

(71) Enthalpy of fusion in the temperature range of +/2 C. of the melting temperature: 26.0 J/g, which corresponds to 44% of the enthalpy of fusion of the whole melting peak.

(72) Enthalpy of fusion in the temperature range of +/4 C. of the melting temperature: 34.1 J/g, which corresponds to 77% of the enthalpy of fusion of the whole melting peak.

(73) Enthalpy of fusion in the temperature range of +/8 C. of the melting temperature: 39.6 J/g, which corresponds to 90.0% of the enthalpy of fusion of the whole melting peak.

(74) Needle Penetration Measurement:

(75) at sample specimen temperature of 22 C.: 5.4 mm;

(76) at sample specimen temperature of 10 C.: 3.4 mm.

(77) Glass coating: crack formation;

(78) Cheese coating: crack formation.

(79) The melting and coating characteristics of the polymer obtained corresponded to comparative example 3.