DTY (Draw Textured Yarn) and production process thereof

Abstract

The invention discloses a DTY (draw textured yarn) and a production process thereof, and relates to the technical field of fiber spinning, the DTY comprises the following raw materials by weight: 55-70% of modified polyester fiber, 15-20% of alginate fiber, 10-15% of corn fiber, and 5-10% of garcinia cambogia fiber; the modified polyester fibers are phytic acid / chitosan composite material modified polyester fibers. The preparation method comprises the following steps: S1, uniformly mixing the modified polyester fibers, the alginate fibers, the corn fibers and the garcinia cambogia fibers, and performing melt extrusion to obtain a mixed master batch; s2, putting the mixed master batch into a spinning machine, and spinning to obtain POY (pre-oriented yarn); s3, the POY is subjected to first roller deformation, hot box deformation, false twister twisting, second roller treatment, network nozzle treatment, hot box shaping and winding forming, and then the DTY is obtained. The DTY provided by the invention has excellent flame retardant property and mechanical property.

Description

Technical Field

[0001] The present application relates to the field of fiber spinning technology, and in particular to a DTY yarn and a production process thereof. Background Art

[0002] DTY yarn, also known as drawn textured yarn, is usually made of polyester chips. It is spun at high speed into polyester pre-oriented yarn, then stretched continuously or simultaneously on a texturing machine, and then deformed by a twister to form a finished yarn. This finished yarn is then spun and processed into fabrics. The resulting fabrics have good thermal insulation, comfortable hand feel, and soft luster. They are widely used in sportswear, outdoor clothing, work clothes, wall coverings, automotive interior decorative fabrics and other fields.

[0003] For related technologies, reference may be made to the Chinese invention patent with authorization announcement number CN113373545B, which discloses an easily colored DTY yarn, which is prepared according to the following steps: S1: POY yarn is prepared by melt extrusion, cooling, oiling, stretching, heat setting and winding of polyester polyester; S2: POY yarn is prepared by wire guide tube, network, heating stretching, false twisting, heat setting and winding to obtain easily colored DTY yarn.

[0004] Regarding the above-mentioned related technologies, since the molecular structure of polyester materials contains a large number of ester bonds and ether bonds, these two chemical bonds are easily broken at high temperatures, so DTY yarn is a flammable textile, and in the process of burning, a large amount of smoke and molten droplets will be generated. The smoke is fatal to the human body and threatens life safety; and the molten droplets are prone to secondary hazards, causing skin burns and other hazards. Therefore, it is of great significance to improve the flame retardant properties of polyester DTY yarn. Summary of the invention

[0005] In order to improve the flame retardant properties of DTY yarn, the present application provides a DTY yarn and a production process thereof.

[0006] The present application provides a DTY yarn, which adopts the following technical solution: A DTY yarn, the raw materials of which include 55-70% modified polyester fiber, 15-20% seaweed fiber, 10-15% corn fiber and 5-10% garcinia cambogia fiber by weight; the modified polyester fiber is a phytic acid / chitosan composite material modified polyester fiber.

[0007] By adopting the above technical scheme, the polyester fiber is modified by the bio-based material phytic acid / chitosan composite material, which can effectively improve the flame retardant properties of the polyester fiber, reduce the melting drop phenomenon, and reduce the release of heat and smoke during combustion; seaweed fiber has very good flame retardant properties, no melting droplets, and will be extinguished immediately after leaving the flame, and no toxic gas will be generated, and no smoke will be generated, which can further improve the flame retardant properties of DTY yarn; corn fiber has the characteristics of moisture absorption, breathability, and warmth retention, and is soft and comfortable, with good resilience. After being compounded with modified polyester fiber, it can effectively improve the mechanical properties of DTY yarn; Garcinia cambogia fiber has excellent wear resistance, and after being compounded with modified polyester fiber, it can effectively improve the wear resistance of DTY yarn; compounding the modified polyester fiber with the natural fiber seaweed fiber, corn fiber, and Garcinia cambogia fiber not only effectively improves the flame retardant and mechanical properties of the DTY yarn, but also has good biocompatibility and green environmental protection.

[0008] Preferably, the phytic acid / chitosan composite material modified polyester fiber is made of the following raw materials in parts by weight: pretreated polyester fiber, phytic acid / chitosan composite material aqueous solution; the solid-liquid ratio of the pretreated polyester fiber and phytic acid / chitosan composite material aqueous solution is 1:(10-15) g / mL.

[0009] By adopting the above technical solution, the polyester fiber is modified by using the phytic acid / chitosan composite material. Preferably, the mass fraction of the phytic acid / chitosan composite material aqueous solution is 10-15%.

[0010] Preferably, the phytic acid / chitosan composite material is made of the following raw materials in parts by weight: 5.43-10.86 parts of carboxymethyl chitosan, 80-160 parts of water, 2.2-4.4 parts of phytic acid, 0.5-1 part of catalyst, and 0.2-0.4 part of pH regulator.

[0011] By adopting the above technical scheme, carboxymethyl chitosan and phytic acid are used as raw materials, and a phytic acid / chitosan composite material is synthesized through an esterification reaction under the promotion of a catalyst. When burning, the flame is weak, there is no smoke and molten droplets, the total heat release is small, and it can effectively play a flame retardant effect, significantly improving the flame retardancy of DTY yarn.

[0012] Preferably, the catalyst is 4-dimethylaminopyridine.

[0013] Preferably, the pH adjuster is imidazole.

[0014] Preferably, the method for preparing the phytic acid / chitosan composite material comprises the following steps: Add water to carboxymethyl chitosan, heat and stir to dissolve at 65-75°C, stand at room temperature for 10-15 minutes, add phytic acid, stir evenly, add 4-dimethylaminopyridine and imidazole, and condense and reflux at 80-90°C for 4-6 hours; pre-freeze the product at -40-(-30)°C for 8-10 hours; freeze-dry it in a freeze dryer at -90-(-80)°C for 48-60 hours, take it out and wash it several times, first dry it in a blast oven at 60-70°C for 3-5 hours, and finally dry it in a vacuum oven at 60-70°C for 12-16 hours to obtain a phytic acid / chitosan composite material.

[0015] Preferably, the method for preparing the phytic acid / chitosan composite material modified polyester fiber comprises the following steps: The polyester fiber is washed alternately with ethanol and deionized water for several times, and then dried in a forced air oven at 60-70° C. for 2-3 hours to obtain a pretreated polyester fiber; The phytic acid / chitosan composite material is added into water, stirred and dissolved at 65-75° C. to obtain a phytic acid / chitosan composite material aqueous solution; the pretreated polyester fiber is immersed in the phytic acid / chitosan composite material aqueous solution at 60-70° C. for 30-60 minutes, and dried to obtain a phytic acid / chitosan composite material modified polyester fiber.

[0016] The present application provides a production process for DTY yarn, which adopts the following technical solution: A production process of DTY yarn comprises the following steps: S1. The modified polyester fiber, seaweed fiber, corn fiber and garcinia cambogia fiber are uniformly mixed and melt-extruded to obtain a mixed masterbatch; S2. The mixed masterbatch is placed in a spinning machine for spinning to obtain POY yarn; S3. The POY yarn is subjected to a first roller, a hot box deformation, a false twister twisting, a second roller, a network nozzle, a hot box shaping, and winding to obtain a DTY yarn.

[0017] Preferably, the melting temperature is 270-290°C.

[0018] In summary, the present application includes at least one of the following beneficial technical effects: 1. This application uses bio-based material phytic acid / chitosan composite material to modify polyester fiber, which can effectively improve the flame retardant properties of polyester fiber, reduce the droplet phenomenon, and reduce the release of heat and smoke during combustion; 2. Seaweed fiber has very good flame retardant properties, no melt droplets, and will be extinguished immediately after leaving the flame. It also produces no toxic gas and no smoke, which can further improve the flame retardant properties of DTY yarn. Corn fiber has the characteristics of moisture absorption, breathability, and warmth retention, and is soft and comfortable, with good resilience. After being compounded with modified polyester fiber, it can effectively improve the mechanical properties of DTY yarn. Garcinia cambogia fiber has excellent wear resistance, and after being compounded with modified polyester fiber, it can effectively improve the wear resistance of DTY yarn. Compounding modified polyester fiber with natural fiber seaweed fiber, corn fiber, and garcinia cambogia fiber not only effectively improves the flame retardant and mechanical properties of DTY yarn, but also has good biocompatibility and is green and environmentally friendly. DETAILED DESCRIPTION

[0019] The present application is further described in detail below in conjunction with embodiments.

[0020] Preparation Example Preparation Example 1 Preparation of phytic acid / chitosan composite material Preparation Example 1.1 Add 80g of water to 5.43g of carboxymethyl chitosan, heat and stir to dissolve at 65°C for 30min, let stand at room temperature for 10min, add 2.2g of phytic acid, stir evenly, add 0.5g of 4-dimethylaminopyridine and 0.2g of imidazole, and react under condensation reflux at 80°C for 4h; pre-freeze the product at -40°C for 8h; then freeze-dry it in a freeze dryer at -90°C for 48h, take it out and rinse it with ethanol 3 times, first dry it at 60°C in a blast oven for 3h, and finally dry it at 60°C in a vacuum oven for 12h to obtain a phytic acid / chitosan composite material.

[0021] Preparation Example 1.2 120 g of water was added to 8.145 g of carboxymethyl chitosan, and the mixture was heated and stirred at 70°C for 40 min to dissolve. After standing at room temperature for 13 min, 3.3 g of phytic acid was added, and after stirring evenly, 0.75 g of 4-dimethylaminopyridine and 0.3 g of imidazole were added. The mixture was condensed and refluxed at 85°C for 5 h. The product was pre-frozen at -35°C for 9 h. The product was freeze-dried in a freeze dryer at -85°C for 54 h. After being taken out, it was rinsed with ethanol 4 times, first dried in a blast oven at 65°C for 4 h, and finally dried in a vacuum oven at 65°C for 14 h to obtain a phytic acid / chitosan composite material.

[0022] Preparation Example 1.3 Add 160g of water to 10.86g of carboxymethyl chitosan, heat and stir to dissolve at 75°C for 50min, add 4.4g of phytic acid after standing at room temperature for 15min, add 1g of 4-dimethylaminopyridine and 0.4g of imidazole after stirring evenly, and react under condensation reflux at 90°C for 6h; pre-freeze the product at -30°C for 10h; freeze-dry it in a freeze dryer at -80°C for 60h, take it out and rinse it with ethanol 5 times, first dry it at 70°C in a blast oven for 5h, and finally dry it at 70°C in a vacuum oven for 16h to obtain a phytic acid / chitosan composite material.

[0023] Preparation Example 2 Preparation of modified polyester fiber Preparation Example 2.1 T1. The polyester fiber was washed alternately with ethanol and deionized water for 3 times, and then dried in a blast oven at 60° C. for 3 h to obtain a pretreated polyester fiber; T2. Add the phytic acid / chitosan composite material prepared in Preparation Example 1.1 into water, stir and dissolve at 65°C to prepare a 10% by mass phytic acid / chitosan composite material aqueous solution; immerse 10 g of pretreated polyester fiber in 100 mL of a 10% by mass phytic acid / chitosan composite material aqueous solution at 60°C for 60 min, and obtain the phytic acid / chitosan composite material modified polyester fiber after drying.

[0024] Preparation Example 2.2 T1. The polyester fiber was washed alternately with ethanol and deionized water 4 times, and then dried in a blast oven at 65° C. for 2.5 h to obtain a pretreated polyester fiber; T2. Add the phytic acid / chitosan composite material prepared in Preparation Example 1.1 into water, stir and dissolve at 70°C to prepare a 10% by mass phytic acid / chitosan composite material aqueous solution; immerse 10 g of pretreated polyester fiber in 100 mL of a 10% by mass phytic acid / chitosan composite material aqueous solution at 65°C for 45 min, and obtain the phytic acid / chitosan composite material modified polyester fiber after drying.

[0025] Preparation Example 2.3 T1. The polyester fiber was washed alternately with ethanol and deionized water for 5 times, and then dried in a blast oven at 70° C. for 2 h to obtain a pretreated polyester fiber; T2. Add the phytic acid / chitosan composite material prepared in Preparation Example 1.1 into water, stir and dissolve at 65°C to prepare a 10% by mass phytic acid / chitosan composite material aqueous solution; immerse 10 g of pretreated polyester fiber in 100 mL of a 10% by mass phytic acid / chitosan composite material aqueous solution at 70°C for 30 min, and dry to obtain a phytic acid / chitosan composite material modified polyester fiber.

[0026] Preparation Example 2.4 The difference between Preparation Example 2.4 and Preparation Example 2.1 is that in Preparation Example 2.4, the mass fraction of the phytic acid / chitosan composite material aqueous solution is configured to be 12%.

[0027] Preparation Example 2.5 The difference between Preparation Example 2.5 and Preparation Example 2.1 is that in Preparation Example 2.5, the mass fraction of the phytic acid / chitosan composite material aqueous solution is configured to be 15%.

[0028] Preparation Example 2.6 The difference between Preparation Example 2.6 and Preparation Example 2.1 is that in Preparation Example 2.6, the mass fraction of the phytic acid / chitosan composite material aqueous solution is configured to 7%.

[0029] Preparation Example 2.7 The difference between Preparation Example 2.7 and Preparation Example 2.1 is that in Preparation Example 2.7, the mass fraction of the phytic acid / chitosan composite material aqueous solution is configured to be 18%.

[0030] Preparation Example 2.8 The difference between Preparation Example 2.8 and Preparation Example 2.1 is that the mass of the pretreated polyester fiber used in T2 in Preparation Example 2.8 is 10 g; the mass fraction of phytic acid / chitosan composite material aqueous solution is 125 mL.

[0031] Preparation Example 2.9 The difference between Preparation Example 2.9 and Preparation Example 2.1 is that the mass of the pretreated polyester fiber used in T2 in Preparation Example 2.9 is 10 g; the mass fraction of phytic acid / chitosan composite material aqueous solution is 150 mL.

[0032] Preparation Example 2.10 The difference between Preparation Example 2.10 and Preparation Example 2.1 is that the mass of the pretreated polyester fiber used in T2 in Preparation Example 2.10 is 10 g; the mass fraction of phytic acid / chitosan composite material aqueous solution is 70 mL.

[0033] Preparation Example 2.11 The difference between Preparation Example 2.11 and Preparation Example 2.1 is that the mass of the pretreated polyester fiber used in T2 in Preparation Example 2.11 is 10 g; the mass fraction of phytic acid / chitosan composite material aqueous solution is 150 mL.

[0034] Preparation Example 2.12 The difference between Preparation Example 2.12 and Preparation Example 2.1 is that the phytic acid / chitosan composite material used in Preparation Example 2.12 comes from Preparation Example 2.2.

[0035] Preparation Example 2.13 The difference between Preparation Example 2.13 and Preparation Example 2.1 is that the phytic acid / chitosan composite material used in Preparation Example 2.13 comes from Preparation Example 2.3. Example

[0036] Example 1 S1. 55 g of the modified polyester fiber prepared in Preparation Example 2.1, 20 g of seaweed fiber, 15 g of corn fiber, and 10 g of Garcinia cambogia fiber were uniformly mixed and melt-extruded at 270 ° C to obtain a mixed masterbatch; S2. The mixed masterbatch is placed in a spinning machine for spinning to obtain POY yarn; S3. The POY yarn is subjected to a first roller, a hot box deformation, a false twister twisting, a second roller, a network nozzle, a hot box shaping, and winding to obtain a DTY yarn.

[0037] Example 2 S1. 63 g of the modified polyester fiber prepared in Preparation Example 2.1, 18 g of seaweed fiber, 12 g of corn fiber, and 7 g of Garcinia cambogia fiber were uniformly mixed and melt-extruded at 280 ° C to obtain a mixed masterbatch; S2. The mixed masterbatch is placed in a spinning machine for spinning to obtain POY yarn; S3. The POY yarn is subjected to a first roller, a hot box deformation, a false twister twisting, a second roller, a network nozzle, a hot box shaping, and winding to obtain a DTY yarn.

[0038] Example 3 S1. 70 g of the modified polyester fiber prepared in Preparation Example 2.1, 15 g of seaweed fiber, 10 g of corn fiber, and 5 g of Garcinia cambogia fiber were mixed uniformly and melt-extruded at 290 ° C to obtain a mixed masterbatch; S2. The mixed masterbatch is placed in a spinning machine for spinning to obtain POY yarn; S3. The POY yarn is subjected to a first roller, a hot box deformation, a false twister twisting, a second roller, a network nozzle, a hot box shaping, and winding to obtain a DTY yarn.

[0039] Example 4 The difference between Example 4 and Example 1 is that the modified polyester fiber used in Example 4 comes from Preparation Example 2.2.

[0040] Example 5 The difference between Example 5 and Example 1 is that the modified polyester fiber used in Example 5 comes from Preparation Example 2.3.

[0041] Example 6 The difference between Example 6 and Example 1 is that the modified polyester fiber used in Example 6 comes from Preparation Example 2.4.

[0042] Example 7 The difference between Example 7 and Example 1 is that the modified polyester fiber used in Example 7 comes from Preparation Example 2.5.

[0043] Example 8 The difference between Example 8 and Example 1 is that the modified polyester fiber used in Example 8 comes from Preparation Example 2.6.

[0044] Example 9 The difference between Example 9 and Example 1 is that the modified polyester fiber used in Example 9 comes from Preparation Example 2.7.

[0045] Example 10 The difference between Example 10 and Example 1 is that the modified polyester fiber used in Example 10 comes from Preparation Example 2.8.

[0046] Embodiment 11 The difference between Example 11 and Example 1 is that the modified polyester fiber used in Example 11 comes from Preparation Example 2.9.

[0047] Example 12 The difference between Example 12 and Example 1 is that the modified polyester fiber used in Example 12 comes from Preparation Example 2.10.

[0048] Example 13 The difference between Example 13 and Example 1 is that the modified polyester fiber used in Example 13 comes from Preparation Example 2.11.

[0049] Embodiment 14 The difference between Example 14 and Example 1 is that the modified polyester fiber used in Example 14 comes from Preparation Example 2.12.

[0050] Embodiment 15 The difference between Example 15 and Example 1 is that the modified polyester fiber used in Example 15 comes from Preparation Example 2.13.

[0051] Comparative Example Comparative Example 1 S1. 65 g of the modified polyester fiber prepared in Preparation Example 2.1, 20 g of seaweed fiber, and 15 g of corn fiber were uniformly mixed and melt-extruded at 270 ° C to obtain a mixed masterbatch; S2. The mixed masterbatch is placed in a spinning machine for spinning to obtain POY yarn; S3. The POY yarn is subjected to a first roller, a hot box deformation, a false twister twisting, a second roller, a network nozzle, a hot box shaping, and winding to obtain a DTY yarn.

[0052] Comparative Example 2 S1. 70 g of the modified polyester fiber prepared in Preparation Example 2.1, 20 g of seaweed fiber, and 10 g of Garcinia cambogia fiber were uniformly mixed and melt-extruded at 270 ° C to obtain a mixed masterbatch; S2. The mixed masterbatch is placed in a spinning machine for spinning to obtain POY yarn; S3. The POY yarn is subjected to a first roller, a hot box deformation, a false twister twisting, a second roller, a network nozzle, a hot box shaping, and winding to obtain a DTY yarn.

[0053] Comparative Example 3 S1. 75 g of the modified polyester fiber prepared in Preparation Example 2.1, 15 g of corn fiber, and 10 g of Garcinia cambogia fiber were mixed uniformly, and melt-extruded at 270 ° C to obtain a mixed masterbatch; S2. The mixed masterbatch is placed in a spinning machine for spinning to obtain POY yarn; S3. The POY yarn is subjected to a first roller, a hot box deformation, a false twister twisting, a second roller, a network nozzle, a hot box shaping, and winding to obtain a DTY yarn.

[0054] Comparative Example 4 The difference between Comparative Example 4 and Example 1 is that the polyester fiber used in Comparative Example 4 is ordinary unmodified polyester fiber.

[0055] Performance testing 1. Using the standard of ASTM D3801-2010, the DTY yarns obtained in Examples 1-15 and Comparative Examples 1-4 were subjected to a vertical combustion test. The test results were divided into three levels: V-2, V-1 and V-0. The flame retardant levels of the samples increased gradually from V-2 and V-1 to V-0. The results are shown in Table 1.

[0056] 2. Referring to GB / T 5454-1997 "Textile Combustion Performance Test Oxygen Index Method", the DTY yarns obtained in Examples 1-15 and Comparative Examples 1-4 were tested for limiting oxygen index. Materials with a limiting oxygen index of <22% are flammable materials, materials with a limiting oxygen index between 22% and 27% are combustible materials, and materials with a limiting oxygen index of >27% are flame retardant materials. The results are shown in Table 1.

[0057] 3. The elongation at break of the DTY yarns obtained in Examples 1-15 and Comparative Examples 1-4 was tested using a YG023B fully automatic single yarn strength tester produced by Changzhou Textile Instrument Factory. The results are shown in Table 1.

[0058] The specific test results are as follows: Table 1 Performance test results It can be seen from the test results in Table 1 that the DTY yarn provided in the present application has a high flame retardant grade, a large limiting oxygen index, and a high elongation at break, which indicates that the raw material ratio and production process of the DTY yarn provided in the present application are conducive to obtaining a DTY yarn with high flame retardant properties and mechanical properties.

[0059] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make modifications to the present embodiment without any creative contribution as needed, but such modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

Claims

1. A DTY yarn, characterized in that: The invention comprises the following raw materials in parts by weight: 55-70% of modified polyester fiber, 15-20% of seaweed fiber, 10-15% of corn fiber and 5-10% of garcinia cambogia fiber; the modified polyester fiber is a phytic acid / chitosan composite material modified polyester fiber.

2. A DTY yarn according to claim 1, characterized in that: The phytic acid / chitosan composite material modified polyester fiber is made of the following raw materials in parts by weight: pretreated polyester fiber and phytic acid / chitosan composite material aqueous solution; the solid-liquid ratio of the pretreated polyester fiber and phytic acid / chitosan composite material aqueous solution is 1: (10-15) g / mL.

3. A DTY yarn according to claim 2, characterized in that: The mass fraction of the phytic acid / chitosan composite material aqueous solution is 10-15%.

4. A DTY yarn according to claim 3, characterized in that: The phytic acid / chitosan composite material is prepared from the following raw materials in parts by weight: 5.43-10.86 parts of carboxymethyl chitosan, 80-160 parts of water, 2.2-4.4 parts of phytic acid, 0.5-1 part of a catalyst, and 0.2-0.4 part of a pH regulator.

5. A DTY yarn according to claim 4, characterized in that: The catalyst is 4-dimethylaminopyridine.

6. A DTY yarn according to claim 4, characterized in that: The pH adjuster is imidazole.

7. A DTY yarn according to claim 4, characterized in that: The preparation method of the phytic acid / chitosan composite material comprises the following steps: Add water to carboxymethyl chitosan, heat and stir to dissolve at 65-75°C, let stand at room temperature for 10-15 minutes, add phytic acid, stir evenly, add catalyst and pH adjuster, condense and reflux at 80-90°C for 4-6 hours; pre-freeze the product at -40-(-30)°C for 8-10 hours; freeze-dry it in a freeze dryer at -90-(-80)°C for 48-60 hours, take it out and wash it several times, first dry it in a blast oven at 60-70°C for 3-5 hours, and finally dry it in a vacuum oven at 60-70°C for 12-16 hours to obtain a phytic acid / chitosan composite material.

8. A DTY yarn according to claim 2, characterized in that: The preparation method of the phytic acid / chitosan composite material modified polyester fiber comprises the following steps: The polyester fiber is washed alternately with ethanol and deionized water for several times, and then dried in a forced air oven at 60-70° C. for 2-3 hours to obtain a pretreated polyester fiber; The phytic acid / chitosan composite material is added into water, stirred and dissolved at 65-75° C. to obtain a phytic acid / chitosan composite material aqueous solution; the pretreated polyester fiber is immersed in the phytic acid / chitosan composite material aqueous solution at 60-70° C. for 30-60 minutes, and dried to obtain a phytic acid / chitosan composite material modified polyester fiber.

9. A process for producing DTY yarn according to any one of claims 1 to 8, characterized in that: The following steps are involved: S1. The modified polyester fiber, seaweed fiber, corn fiber, and garcinia cambogia fiber are uniformly mixed and melt-extruded to obtain a mixed masterbatch; S2. The mixed masterbatch is placed in a spinning machine for spinning to obtain POY yarn; S3. The POY yarn is subjected to a first roller, a hot box deformation, a false twister twisting, a second roller, a network nozzle, a hot box shaping, and winding to obtain a DTY yarn.

10. A production process for DTY yarn according to claim 9, characterized in that: The melting temperature is 270-290°C.

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