阅读说明：本技术 制备具有改良脱水性的接枝橡胶组合物的方法 (Process for preparing graft rubber compositions having improved dewatering ) 是由 T·舒尔茨 W·菲舍尔 于 2019-07-23 设计创作，主要内容包括：本文提出一种用于产生接枝共聚物组合物的方法,所述方法基于丙烯腈-苯乙烯-丙烯酸酯(ASA)或丙烯腈-丁二烯-苯乙烯(ABS)接枝共聚物。通过乳液聚合和沉淀获得的接枝共聚物在沉淀之后显示了改良的脱水行为。基于这一方法,可获得具有低残余湿度的ASA和ABS接枝共聚物。此外,本发明涉及一种用于产生热塑性模塑组合物的方法,所述组合物包含至少一种热塑性苯乙烯共聚物(特别是苯乙烯-丙烯腈共聚物)、通过所述方法获得的接枝共聚物,以及任选的其它组分。(Presented herein is a process for producing a graft copolymer composition based on acrylonitrile-styrene-acrylate (ASA) or acrylonitrile-butadiene-styrene (ABS) graft copolymers. The graft copolymers obtained by emulsion polymerization and precipitation exhibit improved dewatering behavior after precipitation. Based on this process ASA and ABS graft copolymers with low residual humidity can be obtained. Furthermore, the present invention relates to a process for producing a thermoplastic molding composition comprising at least one thermoplastic styrene copolymer (in particular a styrene-acrylonitrile copolymer), the graft copolymer obtained by the process, and optionally further components.)

1. A method for producing a graft copolymer composition, the graft copolymer composition comprising:

b: from 90 to 100% by weight of at least one graft copolymer B comprising:

b1: from 50 to 90% by weight, based on the graft copolymer B, of at least one graft base B1,

the graft base B1 was obtained by emulsion polymerization of:

b11: from 50 to 100% by weight, based on the graft base B1, of at least one monomer B11, the monomer B11 being selected from (meth) acrylic acid C₁-C₈An alkyl ester, a carboxylic acid,

b12: from 0 to 10% by weight, based on the graft base B1, of at least one polyfunctional crosslinking monomer B12;

b13 from 0 to 50% by weight, based on the graft base B1, of at least one further monomer B13, the further monomer B13 being selected from styrene, alpha-methylstyrene, C₁-C₄Alkyl benzeneEthylene, acrylonitrile, methacrylonitrile, isoprene, butadiene, chloroprene, methyl methacrylate, alkylene glycol di (meth) acrylates and vinyl methyl ether,

wherein the sum of B11, B12 and B13 equals 100% by weight, and

b2: from 10 to 50% by weight, based on the graft copolymer B, of at least one graft shell B2,

obtained by emulsion polymerization in the presence of said at least one grafting base B1, of:

b21 from 50 to 100% by weight, based on the graft shell B2, of at least one monomer B21, B21 being selected from styrene, alpha-methylstyrene or styrene and at least one monomer selected from alpha-methylstyrene, p-methylstyrene and (meth) acrylic acid C₁-C₈Mixtures of other monomers of alkyl esters, and

b22 from 0 to 50% by weight, based on the graft shell B2, of at least one monomer B22, the monomer B22 being selected from acrylonitrile or mixtures of acrylonitrile and at least one further monomer selected from methacrylonitrile, acrylamide, vinyl methyl ether, anhydrides of unsaturated carboxylic acids and imides of unsaturated carboxylic acids;

wherein the sum of the graft base B1 and of the graft shell B2 is equal to 100% by weight.

K1 from 0 to 10% by weight of at least one further component K1,

the method comprises the following steps:

a) preparing the at least one graft copolymer B comprising emulsion polymerization of the monomers B21 and B22 in the presence of at least one grafting base B1 to form the at least one graft shell B2, wherein the graft copolymer B is obtained in the form of a latex;

b) precipitating the at least one graft copolymer B after the emulsion polymerization thereof in step a), wherein the graft copolymer B latex is mixed with at least one precipitation solution PS, resulting in a precipitation mixture, wherein the at least one precipitation solution PS comprises at least one alkaline earth metal salt, and wherein the precipitation mixture has a solids content of more than 10.2 wt.%;

c) subjecting the precipitated graft copolymer B to mechanical dehydration, wherein a graft copolymer B having a water content of 40% by weight or less is obtained, and wherein the molar ratio of alkali metal ions to alkaline earth metal ions in the graft copolymer B is 0.16 or less;

d) optionally washing the dehydrated graft copolymer B;

e) optionally drying the dehydrated graft copolymer B obtained in step c) or d);

f) optionally one or more optional components K1 are added.

2. The process according to claim 1, characterized in that the at least one grafting base B1 is obtained by emulsion polymerization of:

b11: 70 to 99.9 wt.%, based on the graft base B1, of at least one (meth) acrylic acid C₁-C₈Alkyl esters as monomers B11;

b12: from 0.1 to 10% by weight, based on the graft base B1, of at least one polyfunctional crosslinking monomer B12;

b13 from 0 to 29.5% by weight, based on the graft base B1, of at least one further monomer selected from the group consisting of styrene, alpha-methylstyrene, C₁-C₄Alkylstyrene, acrylonitrile, methacrylonitrile, isoprene, butadiene, chloroprene, methyl methacrylate, alkylene glycol di (meth) acrylate, and vinyl methyl ether;

wherein the sum of B11, B12 and B13 equals 100 wt.%.

3. The process according to claim 1 or 2, characterized in that the graft copolymer B comprises

B1: from 50 to 70% by weight, based on the graft copolymer B, of exactly one graft base B1; and

b2: 30 to 50% by weight, based on the graft copolymer B, of exactly one graft shell B2 obtained by emulsion polymerization of:

b21: from 50 to 95% by weight, based on the graft shell B2, of at least one aromatic vinyl monomer B21, the aromatic vinyl monomer B21 being selected from styrene, alpha-methylstyrene, or a mixture of styrene and alpha-methylstyrene or methyl (meth) acrylate; and

b22: from 5 to 50% by weight, based on the graft shell B2, of at least one ethylenically unsaturated monomer B22, the ethylenically unsaturated monomer B22 being selected from acrylonitrile or a mixture of acrylonitrile and methacrylonitrile;

wherein the sum of the grafting base B1 and the graft shell B2 is 100% by weight and wherein the particle size of the graft copolymer latex obtained in step a) is in the range from 60 to 140 nm.

4. The process according to claim 1 or 2, characterized in that the graft copolymer B comprises

B1: from 50 to 70% by weight, based on the graft copolymer B, of at least one graft base B1; and

b2': 10 to 20% by weight, based on the graft copolymer B, of at least one graft shell B2' obtained by emulsion polymerization of:

b21 'based on the graft shell B2', 100% by weight of at least one aromatic vinyl monomer B21', the aromatic vinyl monomer B21' being selected from styrene, alpha-methylstyrene, or styrene and at least one monomer selected from alpha-methylstyrene, p-methylstyrene and (meth) acrylic acid C₁-C₄Mixtures of other monomers of alkyl esters, and

b2': from 20 to 30% by weight, based on the graft copolymer B, of at least one graft shell B2' obtained by emulsion polymerization of:

b21': 70 to 80% by weight, based on the graft shell B2 ", of at least one aromatic vinyl monomer B21", the aromatic vinyl monomer B21 "being selected from styrene, alpha-methylstyrene, or a mixture of styrene and alpha-methylstyrene or methyl (meth) acrylate; and

b22': 20 to 30% by weight, based on the graft shell B2', of at least one ethylenically unsaturated monomer B22', the ethylenically unsaturated monomer B22' being selected from acrylonitrile or a mixture of acrylonitrile and methacrylonitrile;

wherein the sum of the grafting base B1, the graft shell B2' and the graft shell B2 "is 100% by weight and wherein the particle size of the graft copolymer latex obtained in step a) is in the range from 400 to 700 nm.

5. The process according to any one of claims 1 to 4, characterized in that the solids content of the precipitation mixture obtained in step b) is in the range of 10.3 to 20 wt.%.

6. The process according to any one of claims 1 to 5, characterized in that, in step B), the graft copolymer B latex is brought with the at least one precipitation solution PS at a temperature T in the range of 30 to 70 ℃₁Down-mixing and thereafter subjecting the precipitation mixture to a temperature T in the range of 70 to 120 ℃₂Hold for at least 5 minutes.

7. The process according to any one of claims 1 to 6, characterized in that the precipitation mixture obtained in step b) comprises more than 0.8 wt. -% of the at least one alkaline earth metal salt, based on the total mass of the precipitation mixture.

8. The process according to any one of claims 1 to 7, characterized in that the pH of the precipitation mixture obtained in step b) is equal to or lower than 10.

9. The process according to any one of claims 1 to 8, characterized in that the water content of the dehydrated graft copolymer B obtained in step c) is in the range of from 20 to 38% by weight.

10. The process according to any one of claims 1 to 9, characterized in that the molar ratio of alkali metal ions to alkaline earth metal ions in the dehydrated graft copolymer B obtained in step c) is in the range of 0.01 to 0.1.

11. A process for producing a thermoplastic molding composition comprising:

a: 5 to 95% by weight of at least one thermoplastic copolymer A, resulting from:

a1: 50 to 95 weight percent, based on the copolymer A, of a monomer A1, the monomer A1 being selected from the group consisting of styrene, alpha-methylstyrene, and styrene and at least one monomer selected from the group consisting of alpha-methylstyrene, p-methylstyrene and (meth) acrylic acid C₁-C₈A mixture of other monomers of the alkyl ester,

a2: from 5 to 50% by weight, based on the copolymer A, of at least one monomer A2, A2 being selected from the group consisting of acrylonitrile and mixtures of acrylonitrile and at least one further monomer selected from the group consisting of methacrylonitrile, acrylamide, vinyl methyl ether, anhydrides of unsaturated carboxylic acids and imides of unsaturated carboxylic acids,

b: 5 to 95% by weight of at least one graft copolymer B as defined in any of claims 1 to 10;

c: from 0 to 90% by weight of at least one further polymeric component C, and

k2: 0 to 10% by weight of at least one further component K2;

the method comprises the following steps:

a) to c) and optionally d) to f) as described in any one of claims 1 to 10;

g) the thermoplastic copolymer a, the at least one graft copolymer B and optionally one or more further polymeric components C and/or optionally one or more further components K2 are mixed.

12. The method according to claim 11, characterized in that the thermoplastic copolymer a is produced from:

a1: 64 to 95% by weight, based on the copolymer A, of a monomer A1, the monomer A1 being selected from styrene and at least one monomer selected from alpha-methylstyrene, p-methylstyrene and (meth) acrylic acid C₁-C₈A mixture of other monomers of the alkyl ester,

a2: 5 to 36% by weight, based on the copolymer A, of a monomer A2, the monomer A2 being selected from acrylonitrile.

13. The process according to claim 11 or 12, characterized in that the thermoplastic molding composition comprises C: from 20 to 60% by weight, based on the total molding composition, of at least one further polymer component C, selected from the group consisting of polycarbonates, polyamides and polyesters.

14. The process according to any one of claims 11 to 13, characterized in that the mixing in step g) is carried out at a temperature in the range of 180 to 300 ℃.

15. A graft copolymer composition obtained by the process according to any one of claims 1 to 10.

16. A thermoplastic molding composition obtained by the process according to any one of claims 11 to 14.

Examples

1. Step a: preparation of styrene-acrylonitrile copolymer grafted polybutyl acrylate latex (graft copolymer B latex)

The following graft copolymer latices B-1 and B-2 were prepared:

a. preparation of graft copolymer B-1 latex (base rubber latex L1: graft rubber latex L2:)

A reaction vessel was charged with 90.2 parts of demineralized water and 0.61 part of C₁₂-C₁₈The sodium salt of an alkane sulfonic acid and 0.23 parts sodium bicarbonate. When the temperature in the reaction vessel reached 59 deg.C, 0.16 parts of sodium persulfate dissolved in 5 parts of demineralized water was added. A mixture of 59.51 parts of butyl acrylate and 1.21 parts of tricyclodecenyl acrylate is added over a period of 210 minutes. The reaction was then allowed to continue for 60 minutes. Finally, the total solids content of the polymer dispersion (graft base B1-1) was 39.6%, and the average particle diameter D of the latex particles was_w(determined by turbidity) was 75 nm.

An amount of 151.9 parts of graft base B1-1 as described above was added to the reaction vessel together with 92.2 parts of demineralized water and 0.14 parts of sodium persulfate dissolved in 3.22 parts of demineralized water. A mixture of 31.18 parts of styrene and 9.31 parts of acrylonitrile is added at a temperature of 61 ℃ over a period of 190 minutes, followed by a postpolymerization time of 60 minutes at 65 ℃. Graft copolymer latex B-1 (polymer dispersion) having a total solid content of 35.5% was obtained. Average particle diameter D of latex particles_w(determined by turbidity) was 87 nm.

b. Preparation of graft copolymer B-2 latex (base rubber latex L3/graft rubber latex L4)

The reaction vessel was charged with 70.66 parts of demineralized water, 0.3 parts of graft base B1-1 (obtained as described above, particle size 75nm) and 0.23 part of sodium bicarbonate. After heating the reaction vessel to 60 ℃, 0.16 parts sodium persulfate dissolved in 5 parts demineralized water was added to the reaction mixture. A mixture of 59.51 parts of butyl acrylate and 1.21 parts of tricyclodecenyl acrylate is added over a period of 210 minutes. In parallel with the first feed, 0.36 part of C was also added over a period of 210 minutes₁₂-C₁₈A solution of the sodium salt of an alkane sulfonic acid in 16.6 parts demineralized water. After 200 minutes from the start of the feed, the temperature was ramped to 65 ℃. Then make the reactionThis should be continued at 65 ℃ for 60 minutes. Finally, the total solids content of the polymer dispersion (graft base B1-2) was 39.4%, and the average particle diameter D of the latex particles was_w(determined by turbidity) was 440nm (determined by turbidity).

154 parts of graft base B1-2 as described above were mixed with 88.29 parts of demineralized water, 0.11 part of C₁₂-C₁₈The sodium salt of the paraffin sulfonic acid was added to the reaction vessel along with 0.14 parts sodium persulfate dissolved in 5.61 parts demineralized water. The reaction mixture was heated to 61 ℃. 13.16 parts were added at 61 ℃ over a period of 60 minutes, followed by a post-polymerization time of 90 minutes, wherein the temperature was increased from 61 ℃ to 65 ℃. A mixture of 20.5 parts styrene and 6.83 parts acrylonitrile was then added to the reaction over a period of 150 minutes. The reaction was allowed to continue at 65 ℃ for an additional 60 minutes. A polymer dispersion with a total solids content of 35.2% was obtained. Average particle diameter D of latex particles_w(determined by turbidity) was 500nm (determined by turbidity).

2. Step b: precipitation of graft copolymer latex B (step B)

Using MgSO₄The solution is used as a precipitation solution PS, using different precipitation conditions (e.g. temperature, MgSO)₄Concentration, ratio of sodium to potassium) to precipitate the graft copolymer latexes B-1 and B-2 prepared as described above.

The precipitated graft copolymer B (graft copolymer B slurry) was obtained as described below. The resulting slurry was transferred to a centrifuge with a diameter of 400mm and centrifuged at 1650rpm for 60s, which caused a centripetal force of 614G. The dehydrated graft copolymer B was obtained as a wet powder.

The residual moisture of the dehydrated graft copolymer was determined by a Mettler-Tolyduo HR73 halogen moisture analyzer. The sodium and magnesium content was determined by ICP-OES using a dry graft copolymer B powder, i.e., after drying the dehydrated graft copolymer in a laboratory oven at 70 ℃ for 2 days.

The effect of different precipitation conditions on residual humidity after centrifugation was investigated and the results are summarized in table 1 below.

Example E-1 (comparative)

112.5g of MgSO₄The solution (19.9wt. -%) was mixed with 2143.1g demineralized water. 451.1g of this solution were used as a pre-charge and heated to 60 ℃. 900g of graft copolymer B-1 latex and 1804.5g of the remainder of the diluted MgSO₄The solutions were added separately over 10 minutes while maintaining the temperature at 60 ℃. The resulting mixture was then heated to 92 ℃ for 5 minutes (sintering).

The resulting slurry was processed as described in the general procedure above.

Example E-2 (inventive)

147.9g of MgSO₄The solution (20wt. -%) was mixed with 1358.8g demineralized water. 301.3g of this solution were used as a pre-charge and heated to 60 ℃. 900g of graft copolymer B-1 latex and 1205.3g of the remaining diluted MgSO4 solution were added separately over 10 minutes, while maintaining the temperature at 60 ℃. The resulting mixture was then heated to 92 ℃ for 5 minutes (sintering).

The resulting slurry was processed as described in the general procedure above.

Example E-3 (inventive)

147.9g of MgSO₄The solution (20.4wt. -%) was mixed with 1207.8g demineralized water. 271.1g of this solution were used as a pre-charge and heated to 60 ℃. 900g of graft copolymer B-1 latex and 1084.5 additional diluted MgSO₄The solutions were added separately over 10 minutes while maintaining the temperature at 60 ℃. The resulting mixture was then heated to 92 ℃ for 5 minutes (sintering).

The resulting slurry was processed as described in the general procedure above.

Example E-4 (inventive)

147.9g of MgSO₄The solution (20.4wt. -%) was mixed with 905.9g demineralized water. 210.7g of this solution were used as a pre-charge and heated to 50 ℃. 900g of graft copolymer B-1 latex and 843g of the remainder of the diluted MgSO₄The solutions were added separately over 10 minutes while maintaining the temperature at 50 ℃. The resulting mixture was then heated to 92 ℃ for 5 minutes (sintering).

The resulting slurry was processed as described in the general procedure above.

Example E-5 (comparative)

87.5g of MgSO₄The solution (19.9wt. -%) was mixed with 2121.4g demineralized water. 441.8g of this solution were used as a pre-charge and heated to 88 ℃. 900g of graft copolymer B-2 latex and 1767.1g of the remainder of the diluted MgSO₄The solutions were added separately over 10 minutes while maintaining the temperature at 88 ℃. The resulting mixture was then heated to 99 ℃ for 5 minutes (sintering).

The resulting slurry was processed as described in the general procedure above.

Example E-6 (inventive)

133g of MgSO₄The solution (20.4wt. -%) was mixed with 1207.1g demineralized water. 268g of this solution was used as a pre-charge and heated to 70 ℃. 900g of graft copolymer B-2 latex and 1072.1g of the remainder of the diluted MgSO₄The solutions were added separately over 10 minutes while maintaining the temperature at 70 ℃. The resulting mixture was then heated to 130 ℃ for 5 minutes (sintering).

The resulting slurry was processed as described in the general procedure above.

The precipitation conditions and results are summarized in table 1 below.

Table 1: graft copolymer composition

¹Solid MgSO (MgSO)₄And demineralized water (DM) are given in parts by weight, based on 100 parts of the solids content of the graft copolymer B.

²The solids content is determined based on the amount of the components used.

³MgSO₄The concentrations are given in weight% based on the total weight of the precipitation mixture.

It is clearly shown that a high alkali to alkaline earth metal ratio (Na/Mg ratio) is disadvantageous due to the higher residual humidity. At a Na/Mg molar ratio higher than 0.16, the precipitated graft copolymer latex dehydrated significantly less.

3. Test program

a. The particle size of the graft base B1 and of the latex of the graft copolymer B was determined to be the average particle diameter D determined by the turbidity as described in Lange, Kolloid-Zeitschrift und Zeitschrift fur Polymer, Band 223, Heft 1_w。

b. The residual moisture of the graft copolymer B after centrifugation was determined by means of a Mettler-Toliduo HR73 halogen moisture analyzer.

c. The sodium and magnesium content in the graft copolymer B was determined by atomic emission spectroscopy and inductively coupled plasma (ICP-AES) after chemical digestion. The dehydrated graft copolymer B was dried in a laboratory oven at 70 ℃ for 2 days. After which 200mg of polymer sample were dissolved in 5ml of nitric acid (microwave assistance at about 200 bar (total pressure of digestion mixture) and about 220 ℃).

The obtained solution was diluted with Millipore (Millipore) water and determined by ICP-AES. Calibration series were obtained by diluting certified reference material.