Halogen-free flame-retardant tpu elastomer composition for matt wire cable and preparation method thereof

Abstract

The present application belongs to the technical field of halogen-free flame-retardant TPU, and specifically discloses a halogen-free flame-retardant TPU elastomer composition for a matte electric wire and cable, which comprises, by weight percentage, TPU 35-84.9%, EVA 10-40%, a phosphorus-nitrogen composite flame-retardant system 5-45%, and an additive 0.1-5%. The phosphorus-nitrogen composite flame-retardant system comprises alkyl phosphate metal salt, melamine derivative and piperazine pyrophosphate. The present application develops a halogen-free flame-retardant TPU elastomer composition for a matte electric wire and cable, which has the characteristics of matte appearance effect, high flame retardancy, softness, wear resistance, oil resistance and the like, and can be applied to the field of consumer electronic product cables.

Description

Technical Field

[0001] This invention relates to the field of halogen-free flame-retardant TPU technology, and in particular to a halogen-free flame-retardant TPU elastomer composition for matte wires and cables and its preparation method. Background Technology

[0002] Polyurethane (PU) is a type of polymer whose main chain contains repeating -NHCOO- structural units. It is polymerized from isocyanate (monomers) and hydroxyl compounds. Due to its highly polar urethane groups, it is insoluble in non-polar solvents and possesses excellent oil resistance, toughness, abrasion resistance, and aging resistance, leading to its widespread application in many fields. Polyurethane comprises two types of materials: thermosetting PU, commonly used in synthetic leather and foaming; and thermoplastic polyurethane (TPU), which combines the processing methods of thermoplastics with the high elasticity of thermosetting PU. TPU is currently experiencing rapid development and is mainly used in shoe soles and cables. In particular, its softness, abrasion resistance, and oil resistance have garnered significant attention in the emerging fields of electric vehicles and charging cables. Similarly, its high elasticity and pleasant feel make it popular in consumer electronics, leading to its widespread use in charging cables and headphone cables for mobile phones, iPads, and other products.

[0003] In the consumer electronics sector, meeting relevant standards is crucial, with flame retardancy being a major challenge. Polyurethane (TPU) is flammable with a low oxygen index, and its dripping phenomenon is severe during high-temperature combustion, making it difficult to meet the required flame retardancy. On the other hand, consumers in the consumer electronics industry seek personalization. TPU, with its glossy surface, lacks a premium feel, and many consumers prefer matte finishes, which convey a sense of luxury. Therefore, to meet market needs, it is necessary to develop matte flame-retardant TPU cable materials that meet both the mandatory flame retardancy requirements of industry standards and the personalized needs of consumers.

[0004] Currently, there are some mature solutions for flame retardancy of TPU elastomers. For example, a compound system based on diethylphosphonate can enable cables to meet VW-1 flame retardancy requirements. There has also been some progress in matte TPU non-flame retardant materials; for instance, a matte effect can be achieved by using a large amount of powder filler. However, under flame retardancy requirements, the presence of a large amount of filler will affect the flame retardant effect of the flame retardant, and will also significantly reduce the mechanical properties of the material, and the pleasant feel of the TPU material will be lost.

[0005] Therefore, for flame-retardant TPU with a matte finish on cables, it is necessary to study solutions to achieve the matte effect and efficient halogen-free flame-retardant systems that are compatible with the matte finish solution, so as to meet the flame-retardant and mechanical performance requirements specified in industry standards. Summary of the Invention

[0006] The purpose of this invention is to provide a halogen-free flame-retardant TPU elastomer composition for matte wires and cables. This TPU elastomer composition has the characteristics of matte appearance, high flame retardancy, softness, wear resistance, and oil resistance, and can be applied to the cable field in the consumer electronics industry.

[0007] To achieve the above objectives, the basic solution provided by this invention is: a halogen-free flame-retardant TPU elastomer composition for matte wires and cables, comprising, by weight percentage: TPU 35-84.9%; EVA 10-40%; a phosphorus-nitrogen composite flame-retardant system 5-45%; and additives 0.1-5%; wherein the phosphorus-nitrogen composite flame-retardant system comprises:

[0008] a) 10–80 wt% of alkyl phosphate metal salts, wherein the average particle size of the alkyl phosphate metal salts is 1 mm. <D50<20μm;

[0009] b) 10–50 wt% of a melamine derivative, wherein the average particle size of the melamine derivative is 1 mm. <D50<20μm;

[0010] c) 10–40 wt% piperazine pyrophosphate, wherein the average particle size of the piperazine pyrophosphate is 1 mm. <D50<20μm。

[0011] This invention relates to the development of matte-finish halogen-free flame-retardant TPU elastomers. A matte finish is achieved through the blending of TPU and EVA, and a highly efficient flame-retardant system for the TPU and EVA blend is provided. This results in a halogen-free flame-retardant matte TPU cable material with excellent performance and appearance.

[0012] Furthermore, the TPU is selected from at least one of polyester polyurethane, polyether polyurethane, polycarbonate polyurethane, polycaprolactone polyurethane, and aliphatic yellowing-resistant polyurethane.

[0013] Furthermore, the EVA mentioned is EVA with a VA content of no more than 18%. A VA content higher than 18% results in a poorer matte finish; the lower limit for VA content is based on available commercial brands. The EVA dosage range is 10-40%; too low a dosage will not achieve a matte appearance, while too high a dosage will damage the mechanical properties of the TPU.

[0014] Furthermore, the structural formula of the alkyl phosphate metal salt is shown in (I):

[0015]

[0016] Where R1 and R2 are straight-chain aliphatic saturated hydrocarbon groups and unsaturated hydrocarbon groups, or aromatic groups, and they can be the same or different; M is a metal element.

[0017] Further, the particle size of the metal alkyl phosphate is 2 < D50 < 10 μm, and the metal alkyl phosphate is aluminum methyl phosphate.

[0018] Further, the melamine derivative includes at least one of melamine pyrophosphate, melamine polyphosphate, melamine cyanurate, and melamine condensate, and the particle size of the melamine derivative is 2 < D50 < 10 μm.

[0019] Further, the average particle size of the piperazine pyrophosphate is 2 < D50 < 10 μm.

[0020] The flame retardant system exists in the material in the form of solid particles, and its particle size will affect the matte effect. It is found that when the average particle size of the flame retardant is less than 20 μm, it can also improve the matte effect of the material, and when it is greater than 20 μm, it will damage the matte effect of the material. Too small particle size increases the difficulty of dispersion and is easy to form aggregates, affecting the appearance.

[0021] In the halogen-free flame retardant TPU elastomer material of the present invention, other additives such as mold inhibitors, antistatic agents, lubricants, anti-UV agents, antioxidants, etc. can be added without affecting the physical properties and flame retardant performance of TPU.

[0022] A preparation method of a halogen-free flame retardant matte TPU elastomer composition for wire and cable includes: mixing each component evenly, and then extruding and pelletizing through processing and shaping equipment such as a twin-screw extruder, a single-screw extruder, a kneader, an open mill, etc.; the extrusion temperature is not higher than 250 °C.

[0023] The halogen-free flame retardant matte TPU elastomer composition is extruded and pelletized in a twin-screw extruder. Since the flame retardant is a heat-sensitive substance, the processing temperature must be controlled, and the maximum temperature of the twin-screw is not more than 250 °C, preferably below 220 °C. The composition is extruded and pelletized in a twin-screw extruder, which has certain requirements for the extrusion equipment. The length-diameter ratio of the twin-screw extruder is not less than 40, preferably not less than 48, and more preferably 52. The composition is extruded and pelletized in a twin-screw extruder, and water-cooled strand drawing, water ring cutting or underwater cutting can be used.

[0024] The halogen-free flame retardant matte TPU elastomer composition prepared according to the above method can be used as a sheath material or insulation material for cables, and cables can be prepared on existing cable equipment through an extrusion molding process.

[0025] Compared with the prior art, the advantages of the present invention are as follows:

[0026] 1. The present invention provides a halogen-free flame-retardant TPU elastomer composition for matte wire and cable, which has characteristics such as a matte appearance effect, high flame retardancy, softness, wear resistance, and oil resistance. The wire and cable materials for consumer electronic products prepared from this TPU elastomer composition can meet the flame retardancy standard of VW-1. Detailed Embodiments

[0027] The present invention will be further described in detail through the following specific embodiments:

[0028] A halogen-free flame-retardant TPU elastomer composition for matte wire and cable, calculated by weight percentage, the raw material composition includes: 35-84.9% of TPU; 10-40% of EVA; 5-45% of a phosphorus-nitrogen composite flame-retardant system; 0.1-5% of additives; wherein, calculated by weight percentage, the phosphorus-nitrogen composite flame-retardant system includes: a) alkyl phosphate metal salt of 10-80wt%, b) melamine derivative of 10-50wt%, c) piperazine pyrophosphate of 10-40wt%;

[0029] The average particle size of the alkyl phosphate metal salt is 1 < D50 < 20μm; the average particle size is preferably 2 < D50 < 10μm, and the alkyl phosphate metal salt is methyl phosphate methyl aluminum;

[0030] The structural formula of the alkyl phosphate metal salt is as shown in (I):

[0031]

[0032] Where R1 and R2 are linear aliphatic saturated hydrocarbon groups and unsaturated hydrocarbon groups, and can also be aromatic groups, which can be the same or different; M is a metal element.

[0033] The melamine derivative includes at least one of melamine pyrophosphate, melamine polyphosphate, melamine cyanurate, and melamine condensate. The average particle size of the melamine derivative is 1 < D50 < 20μm; the average particle size is preferably 2 < D50 < 10μm. The average particle size of piperazine pyrophosphate is 1 < D50 < 20μm, and the average particle size is preferably 2 < D50 < 10μm.

[0034] TPU is selected from at least one of polyester-based polyurethane, polyether-based polyurethane, polycarbonate-based polyurethane, polycaprolactone-based polyurethane, and aliphatic yellowing-resistant polyurethane. EVA is EVA with a VA content not exceeding 18%.

[0035] A preparation method of a halogen-free flame-retardant TPU elastomer composition for matte wire and cable, including: after mixing each component evenly, extruding and pelletizing through processing and forming equipment such as a twin-screw extruder, single-screw extruder, internal mixer, and open mill; the extrusion temperature of the twin-screw extruder is not higher than 250°C.

[0036] Raw material source description:

[0037] (1) TPU, Yantai Wanhua;

[0038] (2) EVA-1, V1803 (VA content 18%), Xinjiang Tianli High-tech Petrochemical Co., Ltd.;

[0039] (3) EVA-2, 3129 (VA content 10%), DuPont, USA;

[0040] (4) EVA-3, 2806 (VA content 28%), Xinjiang Tianli High-tech Petrochemical Co., Ltd.;

[0041] (5) LDPE, 2426, Yangzi Petrochemical;

[0042] (6) Piperazine pyrophosphate: Yuntianhua;

[0043] (7) Melamine pyrophosphate: Yuntianhua;

[0044] (8) Antioxidant, 1010, BASF;

[0045] (9) Antioxidant, 168, BASF;

[0046] (10) Silicone, Zhonglan Chenguang;

[0047] (11) Flame retardant system based on APP, AP750, Clariant;

[0048] (12) Aluminum methyl phosphate (self-made); Preparation process: dimethyl methyl phosphate and aluminum trichloride were reacted at 120°C under vacuum for 8 hours to obtain aluminum methyl phosphate.

[0049] Example 1

[0050] Blending of halogen-free flame-retardant TPU systems

[0051] Pre-dry the TPU, add the pre-weighed TPU, EVA, compound flame retardant system and other additives according to the formula to the high-speed mixer, start the high-speed mixer and stir for 10 minutes to complete the mixing of the halogen-free flame retardant TPU system, and then discharge the material.

[0052] Extrusion granulation of materials

[0053] Set the temperatures of each zone of the twin-screw extruder to the predetermined temperatures (maximum temperature of the screw plasticizing section is 210℃). After the temperature stabilizes for 20 minutes, add the uniformly mixed halogen-free flame-retardant TPU system into the hopper, start the main extruder and feeder, and complete the extrusion granulation of the material. The granulated material is then fed into the silo via a pneumatic conveying system and dried.

[0054] Application and Testing of Materials

[0055] The dried material is injection molded into standard samples according to various testing standards in an injection molding machine, and relevant material performance tests are performed. Qualified cables are produced on wire and cable pulling equipment, samples are taken, and relevant wire and cable tests are conducted. The following performance indicators are mainly focused on:

[0056] Flame retardancy: Tested according to the VW-1 test standard for cable materials. Passing is marked as PASS, and failing is marked as FAIL.

[0057] Mechanical property testing: testing the tensile strength and elongation at break of the material.

[0058] Gloss test: Gloss reflects the brightness of the material surface. The smaller the gloss value, the darker the material surface and the better the matte effect. This application prepares a material with a gloss of less than 10%.

[0059] The materials and proportions in Example 1 are shown in Table 1, and the test results of the obtained material properties are shown in Table 1.

[0060] Example 2

[0061] The implementation process is the same as in Example 1, except that EVA-1 is replaced with EVA-2. The materials and proportions in Example 2 are shown in Table 1, and the test results of the obtained material properties are also shown in Table 1.

[0062] Example 3

[0063] The implementation process is the same as in Example 1, except that the proportion of EVA-1 is adjusted to 12 parts and the proportion of TPU is adjusted to 55.2. The materials and proportions in Example 3 are shown in Table 1, and the test results of the obtained material properties are also shown in Table 1.

[0064] Example 4

[0065] The implementation process is the same as in Example 1, except that the total amount of the flame retardant system remains unchanged, except for the adjustment of the proportion of the flame retardant compound system. The materials and proportions in Example 4 are shown in Table 1, and the material performance test results are also shown in Table 1.

[0066] Example 5

[0067] The implementation process is the same as in Example 1, except that the total proportion of the flame retardant system is increased while maintaining the proportion of each compound component of the flame retardant system. The materials and proportions in Example 5 are shown in Table 1, and the test results of the obtained material properties are also shown in Table 1.

[0068] Comparative Example 1

[0069] The implementation process is the same as in Example 1, except that EVA-1 is replaced with EVA-3. The materials and proportions in Comparative Example 1 are shown in Table 1, and the test results of the obtained material properties are shown in Table 1.

[0070] Comparative Example 2

[0071] The implementation process was the same as in Example 2, except that the amount of EVA-1 was changed to 6 parts and the amount of TPU was changed to 61.2 parts. The materials and proportions in Comparative Example 2 are shown in Table 1, and the test results of the obtained material properties are also shown in Table 1.

[0072] Comparative Example 3

[0073] The implementation process was the same as in Example 1, except that EVA-1 was not used and the TPU ratio was 67.2. The materials and proportions in Comparative Example 3 are shown in Table 1, and the material performance test results are also shown in Table 1.

[0074] Comparative Example 4

[0075] The implementation process is the same as in Example 1, except that the flame retardant system of this application is not used, but an APP-based flame retardant system is used instead. The materials and proportions in Comparative Example 4 are shown in Table 1, and the test results of the obtained material properties are shown in Table 1.

[0076] Table 1 shows the material proportions and test results of the materials obtained in Examples 1-5 and Comparative Examples 1-4.

[0077]

[0078] Comparative Example 5

[0079] The implementation process was the same as in Example 1, except that only aluminum methyl phosphate was used as the flame retardant, and the dosage was 32 parts. The materials and proportions in Comparative Example 5 are shown in Table 2, and the test results of the obtained material properties are shown in Table 2.

[0080] Comparative Example 6

[0081] The implementation process was the same as in Example 1, except that only melamine pyrophosphate was used as the flame retardant, and the dosage was 32 parts. The materials and proportions in Comparative Example 6 are shown in Table 2, and the test results of the obtained material properties are also shown in Table 2.

[0082] Comparative Example 7

[0083] The implementation process was the same as in Example 1, except that only piperazine pyrophosphate was used as the flame retardant, and the dosage was 32 parts. The materials and proportions in Comparative Example 7 are shown in Table 2, and the test results of the obtained material properties are shown in Table 2.

[0084] Comparative Example 8

[0085] The implementation process was the same as in Example 1, except that only aluminum methyl phosphate and melamine pyrophosphate were used as flame retardants, with a dosage of 32 parts. The materials and proportions in Comparative Example 8 are shown in Table 2, and the test results of the obtained material properties are also shown in Table 2.

[0086] Comparative Example 9

[0087] The implementation process was the same as in Example 1, except that only aluminum methyl phosphate and piperazine pyrophosphate were used as flame retardants, with a dosage of 32 parts. The materials and proportions in Comparative Example 9 are shown in Table 2, and the test results of the obtained material properties are also shown in Table 2.

[0088] Comparative Example 10

[0089] The implementation process was the same as in Example 1, except that only melamine pyrophosphate and piperazine pyrophosphate were used as flame retardants, with a dosage of 32 parts. The materials and proportions in Comparative Example 10 are shown in Table 2, and the test results of the obtained material properties are also shown in Table 2.

[0090] Table 2 shows the material proportions and test results of the materials obtained in Comparative Examples 5-10.

[0091]

[0092] In summary, as demonstrated by Examples 1-5 and Comparative Examples 1-10, EVA with a suitable VA content, when used in appropriate amounts, can alter the appearance of TPU, achieving a matte finish. Furthermore, the composite flame-retardant system based on aluminum methyl phosphate in this application is well-suited to the TPU / EVA matte system, solving the appearance and flame-retardant issues of TPU materials and meeting the requirements for TPU cables in the consumer electronics field.

[0093] The above descriptions are merely embodiments of the present invention, and common knowledge regarding specific structures and characteristics is not elaborated upon here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the structure of the present invention, and these should also be considered within the scope of protection of the present invention. These modifications and improvements will not affect the effectiveness of the present invention or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A halogen-free flame-retardant TPU elastomer composition for matte-finish wires and cables, characterized in that, By weight percentage, the raw material composition includes: 35 - 84.9% of TPU; 10 - 40% of EVA; 5 - 45% of a phosphorus-nitrogen composite flame retardant system; 0.1 - 5% of an auxiliary agent; the phosphorus-nitrogen composite flame retardant system includes: a) 10 - 80 wt% of an alkyl phosphonate metal salt, the average particle size of the alkyl phosphonate metal salt being 1 < D50 < 20 μm; b) 10 - 50 wt% of a melamine derivative, the average particle size of the melamine derivative being 1 < D50 < 20 μm; c) 10 - 40 wt% of piperazine pyrophosphate, the average particle size of the piperazine pyrophosphate being 1 < D50 < 20 μm; the EVA is EVA with a VA content not exceeding 18%; the structural formula of the alkyl phosphonate metal salt is as shown in (I): where R1 and R2 are linear aliphatic saturated hydrocarbon groups and unsaturated hydrocarbon groups, and can also be aromatic groups, which can be the same or different; M is a metal element.

2. The halogen-free flame-retardant TPU elastomer composition for matte wires and cables according to claim 1, characterized in that, The TPU is selected from at least one of polyester-based polyurethane, polyether-based polyurethane, polycarbonate-based polyurethane, polycaprolactone-based polyurethane, and aliphatic yellowing-resistant polyurethane.

3. The halogen-free flame-retardant TPU elastomer composition for matte wires and cables according to claim 1, characterized in that, The particle size of the alkyl phosphonate metal salt is 2 < D50 < 10 μm, and the alkyl phosphonate metal salt is methyl methyl phosphate aluminum.

4. The halogen-free flame-retardant TPU elastomer composition for matte wires and cables according to claim 1, characterized in that, The melamine derivative includes at least one of melamine pyrophosphate, melamine polyphosphate, melamine cyanurate, and melamine condensate, and the particle size of the melamine derivative is 2 < D50 < 10 μm.

5. The halogen-free flame-retardant TPU elastomer composition for matte wires and cables according to claim 1, characterized in that, The particle size of the piperazine pyrophosphate is 2 < D50 < 10 μm.

6. The method for preparing the halogen-free flame-retardant TPU elastomer composition for matte wires and cables according to any one of claims 1 to 5, characterized in that, It includes: Obtained by mixing each component evenly and then extruding and pelletizing through a processing and forming device; The extrusion temperature is not higher than 250 °C.

Images