EASILY SOLUBLE AND FREE-FLOWING GRANULAR MATERIAL ON THE BASIS OF HIGH-TEMPERATURE THERMOPLASTICS WITH A LOW CONTENT OF VOLATILE ORGANIC COMPOUNDS

Abstract

Granulate based on high-temperature thermoplastics with a bulk density in the range of 100 to 650 kg/m.sup.3 in accordance with DIN ISO 697:1984 and less than 1% by weight content of volatile organic compounds, and also method for their production and use for the production of membranes or coatings, or for the toughness-modification of reactive resins.

Claims

1. A granulate based on high-temperature thermoplastics, selected from the group of polyaryl ether sulfones, polyaryl ether ketones, polyphenylene sulfides, polyetherimides, polyphenyleneamides, polycarbonates, aromatic polyester carbonates, high-temperature polyamides (HTPA), thermoplastic polyoxazolidones and copolycarbonates or mixtures thereof, with a bulk density in the range of 100 to 650 kg/m.sup.3 in accordance with DIN ISO 697:1984 and less than 1% by weight content of volatile organic compounds.

2. The granulate according to claim 1, wherein said granulate has less than 0.01% content of volatile organic compounds.

3. The granulate according to claim 1, wherein the mass per pellet of said granulate is in the range of 3 to 8.5 mg.

4. The granulate according to claim 1, wherein the L/D ratio of said granulate is in the range of 1/1 to 2.5/1.

5. The granulate according to claim 1, wherein 2 g of the granulate dissolve in 100 ml of N-methylpyrrolidone at 80° C. in less than 60 minutes.

6. The granulate according to claim 1, wherein the flowability value of said granulate is in the range of 1 to 6 seconds, measured in accordance with DIN EN ISO 6186:1998.

7. The granulate according to claim 1, wherein said granulate consists of a high-temperature thermoplastic with an intrinsic viscosity in the range of 40 to 100 cm.sup.3/g, measured in accordance with DIN EN ISO 1628-1:2012-10 in 0.01 g/ml phenol/1.2 ortho-dichlorobenzene, 1:1.

8. The granulate according to claim 1, wherein said granulate consists of a polyaryl ether sulfone as high-temperature thermoplastic.

9. A method for the production of granulates based on high-temperature thermoplastics according to claim 1, comprising the stages of: a) production of a polymer melt via melting of at least one high-temperature thermoplastic with less than 1% by weight content of volatile organic compounds, b) addition of a blowing agent to the polymer melt c) conveying of the polymer melt by way of a gear pump d) conveying of the blowing-agent-containing polymer melt at a temperature in the range of 250° C. to 350° C. through a pelletizing die and e) granulation of the blowing-agent-loaded polymer melt.

10. A method for the production of granulates based on polyaryl ether sulfones according to claim 8, comprising the stages of: a) production of a polymer melt via reaction of a dichlorodiphenyl sulfone component with a bisphenol component as monomers in the presence of alkali metal carbonate in the melt in the absence of solvents or diluents, followed by removal of salts, b) addition of a blowing agent to the polymer melt c) conveying of the polymer melt by way of a gear pump d) conveying of the blowing-agent-containing polymer melt at a temperature in the range of 250° C. to 350° C. through a pelletizing die and e) granulation of the blowing-agent-loaded polymer melt.

11. The method according to claim 9, wherein the granulation in stage e) takes place in an underwater pelletizer operated at a water temperature in the range of 75 to 99° C. and at a pressure in the range of 1 to 10 bar.

12. The method according to claim 9, wherein nitrogen, carbon dioxide, water or mixtures thereof are used as blowing agent.

13. The method according to claim 9, wherein a polyarylene ether sulfone with an intrinsic viscosity in the range of 40 to 100 cm.sup.3/g, measured in accordance with DIN EN ISO 1628-1:2012-10 in 0.01 g/ml phenol/1,2 ortho-dichlorobenzene, 1:1 is used as high-temperature thermoplastic.

14. The use of the granulates according to claim 1 for the production of membranes or coatings, or for the toughness-modification of reactive resins.

15. A method for the production of granulates based on high-temperature thermoplastics according to claim 1, comprising the stages of: a) production of a polymer melt via melting of at least one high-temperature thermoplastic with less than 1% by weight content of volatile organic compounds, b) addition of a blowing agent to the polymer melt c) conveying of the blowing-agent-containing polymer melt at a temperature in the range of 250° C. to 350° C. through a pelletizing die and d) granulation of the blowing-agent-loaded polymer melt.

16. A method for the production of granulates based on polyaryl ether sulfones according to claim 8, comprising the stages of: a) production of a polymer melt via reaction of a dichlorodiphenyl sulfone component with a bisphenol component as monomers in the presence of alkali metal carbonate in the melt in the absence of solvents or diluents, followed by removal of salts, b) addition of a blowing agent to the polymer melt c) conveying of the blowing-agent-containing polymer melt at a temperature in the range of 250° C. to 350° C. through a pelletizing die and d) granulation of the blowing-agent-loaded polymer melt.

17. The method according to claim 15, wherein the granulation in stage d) takes place in an underwater pelletizer operated at a water temperature in the range of 75 to 99° C. and at a pressure in the range of 1 to 10 bar.

18. The method according to claim 15, wherein nitrogen, carbon dioxide, water or mixtures thereof are used as blowing agent.

19. The method according to claim 15, wherein a polyarylene ether sulfone with an intrinsic viscosity in the range of 40 to 100 cm.sup.3/g, measured in accordance with DIN EN ISO 1628-1:2012-10 in 0.01 g/ml phenol/1,2 ortho-dichlorobenzene, 1:1 is used as high-temperature thermoplastic.

Description

EXAMPLES

[0041] Raw materials used: [0042] Ultrason E2010 natural polyether sulfone granulate from BASF SE, density 1370 kg/m.sup.3, intrinsic viscosity 56 cm.sup.3/g, DSC glass transition temperature (10° C./min) 225° C., bulk density 750 g/l. [0043] Ultrason E3010 natural polyether sulfone granulate from BASF SE, density 1370 kg/m.sup.3, intrinsic viscosity 66 cm.sup.3/g, DSC glass transition temperature (10° C./min) 225° C.) bulk density 750 g/l.

[0044] Blowing agent: H.sub.2O

[0045] Test Methods:

[0046] Determination of Bulk Density:

[0047] The bulk density of the blowing-agent-free, porous granulates was determined in accordance with DIN ISO 697:1984.

[0048] Determination of Solubility

[0049] Solubility was determined by in each case dissolving 2 g of polyether sulfone in 100 ml of N-methylpyrrolidone (NMP) in a glass beaker at 80° C. on a vibrator plate at 150 rpm. The time required for complete dissolution of the granulates was measured. The rotation rate of the vibrator plate was 150 rpm for 30 min, and then 300 rpm.

[0050] Determination of Flowability

[0051] The flowability value of the granulates was determined in accordance with DIN EN ISO 6186:1998, method B, and with a test funnel with outlet diameter of 15 mm.

[0052] Determination of Content of Volatile Organic Compounds (VOC)

[0053] The content of volatile organic compounds (VOC) was determined by means of headspace GC/MS as follows.

[0054] Headspace Measurement Conditions:

[0055] Sample temperature: 70° C.

[0056] Temperature control period: 60 min

[0057] Interface temperature: 150° C.

[0058] Standard pressure: 115 kPa

[0059] High pressure: 180 kPa

[0060] Injection time: 0.20 min

[0061] Cryofocusing: 2.5/2.5 min (pre/post)

[0062] Starting weight: 152 mg sample+2 ml DMAA

[0063] GC/MS measurement conditions

[0064] Separation capillary: DB-1 30 m 0.25 mm 1 μm

[0065] Temperature program: 40° C.; 8.5 min; 5° C./min; 260° C.; 10 min

[0066] Inlet pressure: 70 kPa

[0067] Split: ca. 20 ml/min

[0068] Scan: 25-400 amu

[0069] Acetone and isopropanol were used as reference for the quantitative determination.

[0070] Determination of the L/D Ratio:

[0071] The L/D ratio was determined by dynamic image analysis (Camsizer), in which cameras were used to record the shadow projection of granulates flowing through a chute. The characteristic variable L/D was determined from the Camsizer dimension b/I.sub.3, b/I.sub.3=xc,min/xFe,max, where xc,min is the shortest chord in the projection plane and xFe,max, is the maximal Feret diameter in the projection plane. L/D=I.sub.3/b.

[0072] Examples B-1-B-6: Production of porous granulates from polyether sulfones

[0073] Production of the porous granulates took place in an apparatus consisting of a twin-screw extruder from Leistritz divided into eight zones (Z1 . . . Z8) with 18 mm screw diameter and with a length-to-diameter ratio of 40, with a melt pump (gear pump GP), start-up valve (SUV), melt filter, pelletizing die (PD) and an underwater pelletizer (UWP).

[0074] Polyether sulfone (PESU) was metered into the twin-screw extruder and melted. Downstream of about ⅔ of the length of the extruder, the blowing agent H.sub.2O was injected into the extruder with the aid of Isco pumps (piston pumps from Axel Semrau) and an injector incorporated into the extruder. The melt pump (GP) was used to adjust the pressure profile in the extruder (pressure-rotation-rate control) in a manner such that the blowing agent was completely mixed into the polymer melt. The melt pump serves not only to adjust the pressure profile by the twin-screw extruder but also to convey the blowing-agent-impregnated polymer melt through the downstream equipment (the start-up valve, the melt sieve and the pelletizing die). The melt extrudate emerging through the pelletizing die (1 hole with 1.0 mm diameter) was expanded under counter pressure in the underwater pelletizer (UWP) and chopped to give polyether sulfone pellets with a pellet weight in the range of 3-10 mg. The total throughput of the extruder was kept constant here at 4.6 kg/h. The extrudate in the water box was chopped by 6 blades attached to a blade ring. The blade ring here rotates at 3600 rpm. This gives porous pellets, which are transported by the water circuit from the pelletizing die into the drier, and from there are deposited into a collection vessel. Table 1 collates the proportions by weight of the raw materials used. The proportion of water is based on the quantity added per 100 proportions by weight of polymer. Table 2 collates the process parameters.

[0075] Comparative Experiments:

[0076] Comparative experiment V1 was carried out in the same way as examples B-1 to B-6, with the process parameters stated in Table 1.

TABLE-US-00001 TABLE 1 Process parameters Water Water Experi- Through- Extruder temp. pressure Pellet ment put Ultrason 2010 Ultrason 3010 Water temp UWP UWP mass No. g/h Proportions g/h Proportions g/h Proportions g/h (° C.) (° C.) [bar] mg B-1 4603 100 4500.39 2.28 102.61 340 90 5 3.3 B-2 4603 100 4500.39 2.28 102.61 340 90 5 5.7 B-3 4603 100 4500.39 2.28 102.61 340 90 2.5 6.3 B-4 4603 100 4468.93 3.00 134.07 340 90 5 6.4 B-5 4603 100 4468.93 3.00 134.07 340 90 3 6.0 B-6 4603 100 4425.96 4.00 177.04 340 90 3 8.3 V-1 4603 100 4383.81 5.00 219.19 340 90 3 9.3

TABLE-US-00002 TABLE 2 Properties Dry bulk Flow- Exper- density Particle Solubility ability iment trocken mass in NMP VOC value No. Product g/l mg [min] [%] [sec] L/D B-l Ultrason E 296 3.3 47 <0.01 1.1 2010 B-2 Ultrason E 289 5.7 24 <0.01 3.07 1.2 3010 B-3 Ultrason E 271 6.3 29 <0.01 4.07 1.2 3010 B-4 Ultrason E 269 6.4 16 <0.01 3.17 1.5 3010 B-5 Ultrason E 271 6.0 29.0 <0.01 3.2 1.6 3010 B-6 Ultrason E 182 8.3 29 <0.01 4.13 1.8 3010 V-1 Ultrason E 92 9.3 13 <0.01 not 2.7 3010 flowable