METHOD FOR PRODUCING EXPANDED GRANULAR MATERIAL

Abstract

The invention relates to a process for production of expanded foam beads of one or more polyesters based on aliphatic or aliphatic and aromatic dicarboxylic acids and aliphatic diols, comprising the steps of: (a) melting the polyester and admixing the polyester with 1 to 3.5 wt %, based on the polyester, of a carbon dioxide and/or nitrogen blowing agent and also 0.1 to 2 wt % of a nucleating agent, and pressing the nucleated polyester melt, containing blowing agent, through a perforated disk controlled to a temperature between 150 C. and 185 C. and into a pelletizing chamber, (b) using a cutting device to comminute the polymer melt pressed through the perforated disk into individual expanding pellets, (c) discharging the pellets from the pelletizing chamber into a stream of water which is at a temperature of 5 to 90 C. and a pressure of 0.1 bar to 20 bar above ambient pressure.

Claims

1.-14. (canceled)

15. A process for production of expanded foam beads of one or more polyesters based on aliphatic or aliphatic and aromatic dicarboxylic acids and aliphatic diols, comprising the steps of: (a) melting the polyester and admixing the polyester or mixture thereof with 1 to 3.5 wt %, based on the polyester, of carbon dioxide and/or nitrogen blowing agent and also 0.1 to 2 wt % of a nucleating agent, and pressing the nucleated polyester melt, containing blowing agent, through a perforated disk controlled to a temperature between 150 C. and 185 C. and into a pelletizing chamber, (b) using a cutting device to comminute the polymer melt pressed through the perforated disk into individual expanding pellets, (c) discharging the pellets from the pelletizing chamber into a stream of water which is at a temperature of 5 to 90 C. and a pressure of 0.1 bar to 20 bar above ambient pressure, wherein the polyester is biodegradable according to DIN EN 13432 (2000-12).

16. The process according to claim 15, wherein the polyester has a construction as follows: A1) 40 to 100 mol %, based on components A1) and A2), of an aliphatic dicarboxylic acid or mixtures thereof, A2) 0 to 60 mol %, based on components A1) and A2), of an aromatic dicarboxylic acid or mixtures thereof, B) 98.5 to 100 mol %, based on components A1) to A2), of a diol component comprising a C.sub.2 to C.sub.12 alkanediol or mixtures thereof, and C) 0.05 to 1.5 wt %, based on components A1) to A2) and B, of one or more compounds selected from the group consisting of: C1) a compound having at least three groups capable of forming esters, C2) a compound having at least two isocyanate groups, and C3) a compound having at least two epoxide groups.

17. The process according to claim 16, wherein the polyester has a composition as follows: component A1: succinic acid, adipic acid, azaleic acid or sebacic acid or mixtures thereof, component A2: terephthalic acid, and component B: 1,4-butanediol or 1,3-propanediol.

18. The process according to claim 16, wherein the polyester is a polybutylene adipate-co-terephthalate.

19. The process according to claim 16, wherein the polyester is a polybutylene sebacate-co-terephthalate or a mixture of a polybutylene adipate-co-terephthalate and polybutylene-sebacate-co-terephthalate.

20. The process according to claim 15, wherein the polyester of Ai) 90 to 100 mol %, based on components Ai to Aii, of succinic acid; Aii) 0 to 10 mol %, based on components Ai to Aii, of one or more C.sub.6-C.sub.18 dicarboxylic acids; B) 99 to 100 mol %, based on components Ai to Aii, of 1,3-propanediol or 1,4-butanediol or mixtures thereof; C) 0 to 1 wt %, based on components Ai to Aii, B and C, of a diisocyanate and/or a compound having at least three groups capable of forming esters.

21. The process according to claim 15, wherein a blowing agent mixture of carbon dioxide and nitrogen in a ratio of 10:1 to 2:1 is used in step a).

22. The process according to claim 21, wherein the stream of water in step c) has a pressure of 4 bar to 20 bar above ambient pressure.

23. The process according to claim 15, wherein the blowing agent used in step a) exclusively is carbon dioxide wherein the stream of water in step c) has a pressure of 0.5 bar to 5 bar above ambient pressure.

24. A process for production of expanded foam beads of a polyester based on aliphatic or aliphatic and aromatic dicarboxylic acids and aliphatic diols, comprising the steps of: (x) adding aliphatic or aliphatic and aromatic dicarboxylic acids and aliphatic diols, and optionally further reactants, that are used for preparing a polyester melt, into a first stage of a polymer processing machine, (a) introducing the polyester melt into a second polymer processing machine and admixing the polyester melt with 1 to 3.5 wt %, based on the polyester, of blowing agent carbon dioxide and/or nitrogen and also 0.1 to 2 wt % of a nucleating agent, and pressing the nucleated polyester melt, containing blowing agent, through a perforated disk controlled to a temperature between 150 C. and 185 C. and into a pelletizing chamber, (b) using a cutting device to comminute the polymer melt pressed through the perforated disk into individual expanding pellets, (c) discharging the pellets from the pelletizing chamber into a stream of water which is at a temperature of 5 to 90 C. and a pressure of 0.1 bar to 20 bar above ambient pressure, wherein the polyester is biodegradable according to DIN EN 13432 (2000-12)

25. The process according to claim 24, wherein in stage (x) the polyester melt is produced continuously, optionally by addition of a chain extender, and has a melt volume rate (MVR) according to ISO 1133 of 0.5 to 10 cm.sup.3/10 min (190 C., 2.16 kg weight).

26. The process according to claim 24, wherein the chain extender is added in stage (x).

27. The process according to claim 24, wherein the chain extender is added in stage (a) before or at the same time as the blowing agent and the nucleating agent are added.

28. The process according to claim 15, wherein stage (a) is carried out in an extruder, List reactor or static mixer.

Description

COMPARATIVE EXAMPLES

[0127] The experiments were conducted in analogy to example 2 from WO 2014/198779.

[0128] The polymer used was a polyester based on 1,4-benzenedicarboxylic acid, dimethyl ester, 1,4-butanediol, and -hydro--hydroxypoly(oxy-1,4-butanediyl) with a melting range from 200 to 220 C., available for example as Pelprene P-70B from Toyobo Co, Ltd. This polymer was processed according to the method described above, and the bulk density was determined as described above. The bulk densities for each of the blowing agent fractions added are listed in table 1.

[0129] In the comparative examples, the operational parameters set were as follows: the temperature in the extruder in the melting zone and during incorporation of the talc into the polymer was 230 C. The temperature from the extruder housing of the injection site up to the end of the extruder, the melt pump and the diverter valve was lowered to 220 C. A pressure at the end of the extruder of 90 bar was set via the melt pump. The temperature of the perforated disk was increased via electrical heating to a target temperature of 250 C.

TABLE-US-00001 TABLE 1 comparative system Pelprene P-70B CO.sub.2 N.sub.2 Water Comparative quantities quantities pressure Bulk density example [wt %*] [wt %*] [bar] [g/l] V1 1.75 0 5 281 V2 1.75 0 10 419 V3 1.75 0 15 590 V4 1.75 0.3 15 560 V5 1.75 0.3 10 510 V6 1.75 0.3 5 430 V7 0.5 0 1 340 V8 0.75 0 1 267 V9 1 0 1 202 V10 1.25 0 1 153 V11 1.5 0 1 257 V12 1.75 0 1 393 V13 2 0 1 372 V14 2.5 0 1 379 *Based on polyester quantity i-V1

Examples

[0130] The polymer used in examples 1 to 6 was a butylene adipate-co-terephthalate, in feedstock i-1, with a melting range from 100 to 120 C. This polymer was processed according to the method described above, and the bulk density was determined as described above. The bulk densities for each of the blowing agent fractions added are listed in table 2. In the examples, the operational parameters set were as follows: the temperature in the extruder in the melting zone and during incorporation of the talc into the polymer was 180 C. The temperature from the extruder housing of the injection site up to the end of the extruder, the melt pump and the diverter valve was lowered to 160 C. A pressure at the end of the extruder of 90 bar was set via the melt pump. The temperature of the perforated disk was increased via electrical heating to a target temperature of 170 C.

TABLE-US-00002 TABLE 2 polybutylene adipate-co-terephthalate i-1 - examples 1 to 6 CO.sub.2 N.sub.2 quantities quantities Water Bulk density Examples [wt %*] [wt %*] pressure [bar] [g/l] 1 2 0.3 5 135 2 2 0.3 7.5 120 3 2 0.3 10 105 4 2 0.3 15 108 5 2 0 1 102 6 3 0 5 127 *based on polyester i-1

[0131] Example 4 was repeated, but polyester i-1 was not isolated in between but was instead introduced as a polymer melt, via a heated pipeline, into stage (a). Expanded pellets (foam beads) having a bulk density of 105 g/l and a surface quality similar to those of example 4 were obtained.

[0132] The polymer used in examples 7 to 9 was a butylene sebacate-co-terephthalate i-2, with a melting range from 100 to 120 C. This polymer was processed according to the method described above, and the bulk density was determined as described above. The bulk densities for each of the blowing agent fractions added are listed in table 3. In the examples, the operational parameters set were as follows: the temperature in the extruder in the melting zone and during incorporation of the talc into the polymer was 180 C. The temperature from the extruder housing of the injection site up to the end of the extruder, the melt pump and the diverter valve was lowered to 160 C. A pressure at the end of the extruder of 90 bar was set via the melt pump. The temperature of the perforated disk was increased via electrical heating to a target temperature of 170 C.

TABLE-US-00003 TABLE 2 polybutylene sebacate-co-terephthalate i-2 - examples 7 to 9 CO.sub.2 N.sub.2 Water quantities quantities pressure Bulk density Example [wt %*] [wt %*] [bar] [g/l] 7 2 0.3 7.5 99 8 2 0.3 10 96 9 2 0.3 15 90 *based on polyester i-2

[0133] In a guideline experiment, example 1 was repeated with polybutylene succinate i-3 Instead of polyester i-1 to give expanded foam beads having a bulk density of 192 g/l. By increasing the temperature of the perforated disk and/or of the water, expanded foam beads with even lower bulk densities ought also to be realizable for polyester i-3.

[0134] As set out in table 3 below, the expanded foam beads of examples 2, 3, 7, 8 and 9 were fused in an EHV-C automatic molding machine from Erlenbach to form slabs of lengthwidthheight=505020 [mm].

TABLE-US-00004 TABLE 3 fusing using automatic EPS molding machine Transverse Transverse steam steam moving side fixed side Autoclave Autoclave Pres- Pres- moving side fixed side Time sure Time sure Time Pressure Time Pressure Example [s] [bar] [s] [bar] [s] [bar] [s] [bar] 2 6 0.2 6 0.3 2 0.7 2 0.7 3 6 0.2 6 0.3 2 0.2 2 0.3 7 2 0.1 2 0.1 2 0.1 2 0.1 8 2 0.1 2 0.1 2 0.1 2 0.1 9 4 0.1 4 0.1 2 0.1 2 0.1

[0135] The following pressure test of table 4 was carried out in accordance with the German version of standard EN 826: 2013 (Determination of behavior under pressure exposure for thermal insulating materials for building). The rebound elasticity (rebound) was determined according to standard DIN 53512 of April 2000.

TABLE-US-00005 TABLE 4 mechanical data under pressure Pressure test F10% F25% F50% Rebound Density Pressure Pressure Pressure Density Rebound Example Sample [kg/m.sup.3] [kPa] [kPa] [kPa] [kg/m.sup.3] [%] 2 1 261.9 23.9 160.9 452.3 267.8 64.2 2 259.8 35.2 190.5 514.3 262.2 63.6 3 272.5 63.0 3 1 236.7 28.7 165.4 407.1 241.4 63.6 2 279.7 66.5 260.4 700.6 254.2 63.0 3 242.5 33.0 183.1 495.0 299.9 62.0 7 1 276.8 24.8 129.8 370.2 276.2 67.8 2 236.0 22.2 95.3 285.8 241.7 66.2 3 261.2 41.2 141.9 389.7 281.9 67.6 8 1 205.9 37.4 111.5 281.8 172.2 71.8 2 190.3 18.6 78.8 204.4 195.5 67.8 3 145.5 12.8 52.0 143.6 210.0 70.6 9 1 196.6 18.6 66.7 208.6 186.6 74.8 2 184.4 21.1 68.8 196.0 185.9 76.0 3 177.1 14.8 58.1 180.3 202.9 73.6