CN112724656A

CN112724656A - Halogen-free flame-retardant TPU cable material and preparation method and application thereof

Info

Publication number: CN112724656A
Application number: CN202011596901.3A
Authority: CN
Inventors: 钱洪祥; 钱建中; 周伟; 王强; 史献峰; 万鹏程
Original assignee: Fujian Huide New Material Co ltd
Current assignee: Fujian Huide New Material Co ltd
Priority date: 2020-12-28
Filing date: 2020-12-28
Publication date: 2021-04-30

Abstract

The invention provides a halogen-free flame-retardant TPU cable material, a preparation method and application thereof, wherein the halogen-free flame-retardant TPU cable material comprises the following raw materials in parts by weight: 54-79 parts of thermoplastic polyurethane elastomer, 7-11 parts of A flame retardant, 7-18 parts of B flame retardant, 5-10 parts of compatilizer and 1-5 parts of smoke suppressant; the flame retardant A is a phosphorus flame retardant, and the flame retardant B is a modified phosphorus-nitrogen composite flame retardant. The halogen-free flame-retardant TPU cable material disclosed by the invention not only has good flame retardance and smoke suppression, but also has the characteristics of migration resistance, hydrolysis resistance and high flexibility, and is suitable for multiple fields of cables, shoe materials or medical materials and the like.

Description

Halogen-free flame-retardant TPU cable material and preparation method and application thereof

Technical Field

The invention belongs to the technical field of thermoplastic polyurethane elastomers, relates to a halogen-free flame-retardant TPU cable material, and a preparation method and application thereof, and particularly relates to a low-smoke halogen-free flame-retardant TPU cable material, and a preparation method and application thereof.

Background

The thermoplastic Polyurethane elastomer is a novel (AB) n segmented linear copolymer, which is called Thermoplastic Polyurethane (TPU) for short in English, and is widely applied to a plurality of fields such as cables, shoe materials, films, medical treatment and the like by virtue of excellent wear resistance, tensile property, resilience, aging resistance and weather resistance.

In the field of cables, because the TPU material belongs to a flammable material, the Limiting Oxygen Index (LOI) is only about 20 percent, and various defects of serious dripping, easy continuous combustion, large smoke quantity, strong and toxic odor and the like exist. With the attention of various fields on environmental protection and safety, the traditional bromine-antimony flame retardant system has high flame retardant efficiency and small dosage, but generates toxic HBr and a large amount of dense smoke during combustion, and is not suitable for the development trend of environment-friendly flame retardants. Therefore, environmental protection and flame retardant modification are urgently needed to meet the standard requirements of cables.

In recent years, phosphorus-nitrogen flame-retardant systems become research hotspots of halogen-free flame-retardant systems, and the phosphorus-nitrogen flame-retardant systems have the characteristics of high flame-retardant efficiency and smoke abatement. CN109385071A discloses a TPU material with flame retardant property reaching the vertical burning V0 grade and a preparation method thereof, the invention directly mixes a powder phosphorus nitrogen flame retardant system with the TPU material to obtain the flame retardant TPU material, the production method can solve the problem of flammability of the TPU material, but the mechanical property, aging resistance and hydrolysis resistance of the prepared flame retardant TPU material are greatly reduced, and other properties required by cables are difficult to meet. In general, the main disadvantages of the flame retardant applied to the TPU material are: easy precipitation and whitening, large addition amount, poor hydrolysis resistance and the like.

Therefore, in the art, it is desirable to develop a halogen-free flame retardant TPU cable material that can meet the flame retardant requirements and minimize the loss of other properties of the TPU material.

Disclosure of Invention

Aiming at the defects of the prior art, the invention aims to provide a halogen-free flame-retardant TPU cable material, and a preparation method and application thereof. The halogen-free flame-retardant TPU cable material disclosed by the invention not only has good flame retardance and smoke suppression, but also has the characteristics of migration resistance, hydrolysis resistance and high flexibility, and is suitable for multiple fields of cables, shoe materials or medical materials and the like.

In order to achieve the purpose, the invention adopts the following technical scheme:

on one hand, the invention provides a halogen-free flame retardant TPU cable material, which comprises the following raw materials in parts by weight:

the flame retardant A is a phosphorus flame retardant, and the flame retardant B is a modified phosphorus-nitrogen composite flame retardant.

In the invention, the flame retardant A is a liquid phosphorus flame retardant, the flame retardant B is a powder flame retardant, and the liquid flame retardant and the powder flame retardant are compounded, so that the addition amount of the powder flame retardant can be reduced, and the performance of the TPU material can be maintained to the greatest extent; the addition of the smoke suppressant can make the TPU cable material have smoke suppression performance.

In the invention, in the raw materials for preparing the halogen-free flame-retardant TPU cable material, the thermoplastic polyurethane elastomer can be used in an amount of 54-79 parts, such as 54 parts, 60 parts, 65 parts, 70 parts, 75 parts or 79 parts.

In the preparation raw materials of the halogen-free flame-retardant TPU cable material, the amount of the flame retardant A can be 7-11 parts, such as 7 parts, 8 parts, 9 parts, 10 parts or 11 parts.

In the preparation raw materials of the halogen-free flame-retardant TPU cable material, the amount of the flame retardant B can be 7-18 parts, such as 7 parts, 10 parts, 13 parts, 15 parts or 18 parts.

In the preparation raw material of the halogen-free flame-retardant TPU cable material, the amount of the compatilizer can be 5-10 parts, such as 5 parts, 6 parts, 8 parts, 9 parts or 10 parts.

In the preparation method, the amount of the smoke suppressant in the raw materials for preparing the halogen-free flame-retardant TPU cable material can be 1-5 parts, such as 1 part, 2 parts, 3 parts, 4 parts or 5 parts.

In the present invention, the thermoplastic polyurethane elastomer is any one of polyether TPU, polyester TPU or PCL TPU, or a combination of at least two thereof. Combinations of the at least two, such as polyether TPU and polyester TPU, polyether TPU and PCL TPU, and the like.

Preferably, the hardness of the thermoplastic polyurethane elastomer is 85A to 95A, such as 85A, 88A, 90A or 95A.

In the present invention, the flame retardant a is any one of dimethyl methyl phosphate (DMMP), tris (dimethylphenyl) phosphate (TXP), cresyldiphenyl phosphate (CDP), triisopropylphenyl phosphate (IPPP), or Fyrol-a710 phosphorus flame retardants, or a combination of at least two thereof. Combinations of at least two of the foregoing, such as dimethyl methylphosphonate and tris (dimethylphenyl) phosphate, cresyldiphenyl phosphate and triisopropylphenyl phosphate, and the like.

In the present invention, the B flame retardant is aluminum hypophosphite (ALHP) and Melamine Cyanurate (MC) modified with a hydrophobic modifier.

Preferably, the hydrophobic modifier is a silicone hybrid polymer.

Preferably, the silicone hybrid polymer is a controlled radical type silane hyperdispersant.

Preferably, the preparation method of the B flame retardant comprises the following steps:

and drying the aluminum hypophosphite and the melamine cyanurate, mixing, adding the hydrophobic modifier to the surface of the mixture, and stirring and mixing to obtain the B flame retardant.

Organic silicon hybrid polymer is used for carrying out surface organic hydrophobic modification on aluminum hypophosphite and melamine cyanurate, so that the hydrophobicity of the obtained B flame retardant is improved to over 98 percent, the dispersibility of the B flame retardant in the TPU material is better, and the water-resistant period of the obtained low-smoke halogen-free flame retardant TPU material is longer; meanwhile, the aluminum hypophosphite and the melamine cyanurate can achieve the effect of synergistic flame retardance.

Preferably, the mass ratio of the aluminum hypophosphite to the melamine cyanurate is (0.8-1.2): (1.8-2.2), for example, 4:9, 4:11, 2:3, 6:11, or 1: 2.

Preferably, the drying is performed in an oven at 100 to 110 ℃ (e.g., 100 ℃, 103 ℃, 105 ℃ or 110 ℃, etc.).

Preferably, the drying time is 2-3 h, such as 2h, 2.5h or 3 h.

Preferably, the stirring speed of the stirring and mixing is 800-1000 rpm, such as 800rpm, 900rpm or 1000 rpm.

Preferably, after the temperature of the high-speed mixer is heated to 80-100 ℃ (for example, 80 ℃, 90 ℃ or 100 ℃ and the like), stopping heating, adding the mixture of aluminum hypophosphite and melamine cyanurate and the hydrophobic modifier, and stopping stirring when the temperature of the high-speed mixer is increased to 110-120 ℃ (for example, 110 ℃, 115 ℃ or 120 ℃ and the like);

preferably, the mixture is discharged while hot after being stirred and mixed, so as to obtain the flame retardant B.

In the invention, the compatilizer is one or a combination of at least two of maleic anhydride grafted ethylene-vinyl acetate copolymer (MAH-g-EVA), maleic anhydride grafted polyethylene (MAH-g-PE) or maleic anhydride grafted styrene-ethylene-butylene-styrene block copolymer (MAH-g-SEBS). Combinations of said at least two, such as MAH-g-EVA and MAH-g-PE, MAH-g-EVA and MAH-g-SEBS, and the like.

In the invention, the smoke suppressant is any one or a combination of at least two of hydroxide, molybdenum compound, magnesium-zinc compound, magnesium-aluminum compound or iron compound. Combinations of the at least two, such as hydroxides and molybdenum compounds, magnesium-zinc compounds, iron compounds, and the like.

In the invention, the halogen-free flame retardant TPU cable material also comprises 0.5-1 (such as 0.5, 0.6, 0.8 or 1) part by weight of lubricant.

Preferably, the lubricant is any one of stearate, erucamide, polyethylene wax or silicone powder or a combination of at least two of them. Combinations of the at least two, such as stearate and erucamide, polyethylene wax and silicone powder, and the like.

Preferably, the halogen-free flame retardant TPU cable material further comprises 0.5-1 (for example, 0.5, 0.6, 0.8 or 1) part by weight of an antioxidant.

Preferably, the antioxidant is pentaerythritol tetrakis [ beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate ] (antioxidant 1010).

In another aspect, the present invention provides a preparation method of the halogen-free flame retardant TPU cable material, including the following steps:

(1) mixing thermoplastic polyurethane elastomer TPU, compatilizer and smoke suppressant to obtain a mixture;

(2) and (2) feeding the mixture obtained in the step (1) into a double-screw extruder from a main feeding port, adding a flame retardant A into the tail end of a conveying and melting section of the extruder, adding a flame retardant B into the extruder from a side feeding port, extruding and granulating to obtain the halogen-free flame-retardant TPU cable material.

In the invention, the mixing time in the step (1) is 10-15 min, such as 10min, 12min or 15 min.

Preferably, the A flame retardant of step (2) is injected with a liquid metering pump. The flame retardant A is injected into the tail end of a conveying melting section of the double-screw extruder by a liquid metering pump, so that the flame retardant A can be uniformly dispersed in the TPU matrix.

Preferably, the temperature of the melting section of the twin-screw extruder is 160 to 190 ℃ (for example, 160 ℃, 180 ℃ or 190 ℃), the temperature of the kneading section is 170 to 195 ℃ (for example, 170 ℃, 180 ℃ or 195 ℃), the temperature of the exhaust homogenizing section is 175 to 200 ℃ (for example, 175 ℃, 190 ℃ or 200 ℃) and the temperature of the extruder head is 205 to 215 ℃ (for example, 205 ℃, 210 ℃ or 215 ℃).

In still another aspect, the invention provides the application of the halogen-free flame retardant TPU cable material as described above in the preparation of cables, shoe materials or medical materials.

Compared with the prior art, the invention has the following beneficial effects:

(1) the flame retardant A is a liquid phosphorus flame retardant, the flame retardant B is a powder flame retardant, the liquid phosphorus flame retardant is used for replacing part of powder flame retardant, the liquid phosphorus flame retardant is injected by a liquid metering pump at the tail section of a conveying and melting section of an extruder, the using amount of the powder flame retardant is reduced, the liquid phosphorus flame retardant is added after TPU is completely melted, the compatibility is good, the phenomenon of uneven mixing of various raw materials is reduced, the precipitation resistance is good, and the product quality of TPU cable materials can be ensured; the addition of the smoke suppressant can make the TPU cable material have smoke suppression performance.

(2) Organic silicon hybrid polymers are used for carrying out surface organic hydrophobic modification on aluminum hypophosphite and melamine cyanurate, so that a great amount of polar groups are introduced to the surface of the flame retardant B while the flame retardant B obtains hydrophobicity, the water resistance, compatibility and precipitation resistance of the TPU cable material are improved, and the loss of the mechanical property of the material is reduced; meanwhile, the aluminum hypophosphite and the melamine cyanurate can achieve the effect of synergistic flame retardance.

Drawings

FIG. 1 is a schematic view of the structure of each section of the twin-screw extruder of the present invention.

Detailed Description

The technical solution of the present invention is further explained by the following embodiments. It should be understood by those skilled in the art that the examples are only for the understanding of the present invention and should not be construed as the specific limitations of the present invention.

Example 1

In this embodiment, a halogen-free flame retardant TPU cable material is provided, and the raw materials for preparing the halogen-free flame retardant TPU cable material include the following components in parts by weight:

wherein the B flame retardant is aluminum hypophosphite and melamine cyanurate modified by using a controlled free radical type silane hyperdispersant.

The preparation method of the B flame retardant comprises the following steps:

heating the high-speed mixer to 80 ℃, stopping heating, drying aluminum hypophosphite and melamine cyanurate in a mass ratio of 4:9 in an oven at 105 ℃ for 2 hours, then pouring the dried aluminum hypophosphite and melamine cyanurate into the high-speed mixer for mixing, adding a hydrophobic modifier to the surface of the mixture, stirring and mixing at the rotating speed of 800rpm, stopping stirring when the temperature of the high-speed mixer rises to 120 ℃, and discharging the mixture while the mixture is hot to obtain the flame retardant B.

The preparation method of the halogen-free flame-retardant TPU cable material comprises the following steps:

(1) mixing polyether type TPU, MAH-g-SEBS, hydroxide, silicone powder and antioxidant 1010 for 10min to obtain a mixture;

(2) and (2) feeding the mixture obtained in the step (1) into a double-screw extruder from a main feeding port, injecting DMMP into the extruder at the end of a conveying and melting section by using a liquid metering pump, adding a B flame retardant from a side feeding port, extruding and granulating to obtain the halogen-free flame-retardant TPU cable material.

Wherein the temperature of the conveying melting section of the double-screw extruder is 160 ℃, the temperature of the mixing section is 170 ℃, the temperature of the exhaust homogenizing section is 175 ℃, and the temperature of the head of the extruder is 205 ℃. The structure of each section of the double-screw extruder is schematically shown in figure 1.

Example 2

The preparation method of the B flame retardant comprises the following steps:

heating the high-speed mixer to 100 ℃, stopping heating, drying aluminum hypophosphite and melamine cyanurate in a mass ratio of 4:11 in an oven at 105 ℃ for 2 hours, then pouring the dried aluminum hypophosphite and melamine cyanurate into the high-speed mixer for mixing, adding a hydrophobic modifier to the surface of the mixture, stirring and mixing at the rotating speed of 900rpm, stopping stirring when the temperature of the high-speed mixer rises to 120 ℃, and discharging the mixture while the mixture is hot to obtain the flame retardant B.

(1) mixing polyether type TPU, MAH-g-EVA, molybdenum compound, stearate and antioxidant 1010 for 12min to obtain a mixture;

Wherein the temperature of the conveying melting section of the double-screw extruder is 180 ℃, the temperature of the mixing section is 190 ℃, the temperature of the exhaust homogenizing section is 200 ℃, and the temperature of the extruder head is 210 ℃. The structure of each section of the double-screw extruder is schematically shown in figure 1.

Example 3

The preparation method of the B flame retardant comprises the following steps:

heating the high-speed mixer to 90 ℃, stopping heating, drying aluminum hypophosphite and melamine cyanurate in a mass ratio of 2:3 in an oven at 110 ℃ for 2.5h, pouring the dried aluminum hypophosphite and melamine cyanurate into the high-speed mixer for mixing, adding a hydrophobic modifier to the surface of the mixture, stirring and mixing at the rotating speed of 1000rpm, stopping stirring when the temperature of the high-speed mixer rises to 115 ℃, and discharging the mixture while the mixture is hot to obtain the flame retardant B.

(1) mixing polyester TPU, MAH-g-EVA, hydroxide, silicone powder and antioxidant 1010 for 13min to obtain a mixture;

(2) and (2) feeding the mixture obtained in the step (1) into a double-screw extruder from a main feeding port, injecting TXP into the extruder at the end of a conveying and melting section of the extruder by using a liquid metering pump, adding a B flame retardant from a side feeding port, extruding and granulating to obtain the halogen-free flame-retardant TPU cable material.

Wherein the temperature of the conveying melting section of the double-screw extruder is 170 ℃, the temperature of the mixing section is 180 ℃, the temperature of the exhaust homogenizing section is 190 ℃, and the temperature of the extruder head of the extruder is 215 ℃. The structure of each section of the double-screw extruder is schematically shown in figure 1.

Example 4

The preparation method of the B flame retardant comprises the following steps:

heating the high-speed mixer to 85 ℃, stopping heating, drying aluminum hypophosphite and melamine cyanurate in a mass ratio of 6:11 in an oven at 100 ℃ for 2.5 hours, then pouring the dried mixture into the high-speed mixer for mixing, adding a hydrophobic modifier to the surface of the mixture, stirring and mixing at a rotating speed of 800rpm, stopping stirring when the temperature of the high-speed mixer rises to 110 ℃, and discharging the mixture while the mixture is hot to obtain the flame retardant B.

(1) mixing polyester TPU, MAH-g-PE, molybdenum compound, erucamide and antioxidant 1010 for 14min to obtain a mixture;

Wherein the temperature of the conveying melting section of the double-screw extruder is 190 ℃, the temperature of the mixing section is 195 ℃, the temperature of the exhaust homogenizing section is 200 ℃, and the temperature of the head of the extruder is 205 ℃. The structure of each section of the double-screw extruder is schematically shown in figure 1.

Example 5

The preparation method of the B flame retardant comprises the following steps:

heating the high-speed mixer to 95 ℃, stopping heating, drying aluminum hypophosphite and melamine cyanurate in a mass ratio of 1:2 in an oven at 105 ℃ for 3 hours, then pouring the dried aluminum hypophosphite and melamine cyanurate into the high-speed mixer for mixing, adding a hydrophobic modifier to the surface of the mixture, stirring and mixing at the rotating speed of 900rpm, stopping stirring when the temperature of the high-speed mixer rises to 115 ℃, discharging the mixture while the mixture is hot, and obtaining the flame retardant B.

(1) mixing the PCL type TPU, the MAH-g-PE, the hydroxide, the silicone powder and the antioxidant 1010 for 15min to obtain a mixture;

(2) and (2) feeding the mixture obtained in the step (1) into a double-screw extruder from a main feeding port, injecting CDP into the tail end of a conveying and melting section of the extruder by using a liquid metering pump, adding a B flame retardant from a side feeding port, extruding and granulating to obtain the halogen-free flame-retardant TPU cable material.

Wherein the temperature of the conveying melting section of the double-screw extruder is 160 ℃, the temperature of the mixing section is 175 ℃, the temperature of the exhaust homogenizing section is 180 ℃, and the temperature of the head of the extruder is 205 ℃. The structure of each section of the double-screw extruder is schematically shown in figure 1.

Example 6

The preparation method of the B flame retardant comprises the following steps:

heating the high-speed mixer to 90 ℃, stopping heating, drying aluminum hypophosphite and melamine cyanurate in a mass ratio of 4:9 in an oven at 110 ℃ for 3 hours, pouring the dried aluminum hypophosphite and melamine cyanurate into the high-speed mixer for mixing, adding a hydrophobic modifier to the surface of the mixture, stirring and mixing at the rotating speed of 1000rpm, stopping stirring when the temperature of the high-speed mixer rises to 120 ℃, and discharging the mixture while the mixture is hot to obtain the flame retardant B.

(1) mixing the PCL type TPU, the MAH-g-SEBS, the iron compound, the polyethylene wax and the antioxidant 1010 for 10min to obtain a mixture;

Wherein the temperature of the conveying melting section of the double-screw extruder is 170 ℃, the temperature of the mixing section is 190 ℃, the temperature of the exhaust homogenizing section is 195 ℃, and the temperature of the extruder head is 210 ℃. The structure of each section of the double-screw extruder is schematically shown in figure 1.

Example 7

The preparation method of the B flame retardant comprises the following steps:

heating the high-speed mixer to 90 ℃, stopping heating, drying aluminum hypophosphite and melamine cyanurate in a mass ratio of 4:11 in an oven at 100 ℃ for 3 hours, pouring the dried aluminum hypophosphite and melamine cyanurate into the high-speed mixer for mixing, adding a hydrophobic modifier to the surface of the mixture, stirring and mixing at the rotating speed of 900rpm, stopping stirring when the temperature of the high-speed mixer rises to 110 ℃, and discharging the mixture while the mixture is hot to obtain the flame retardant B.

(1) mixing the PCL type TPU, the MAH-g-SEBS, the iron compound, the stearate and the antioxidant 1010 for 12min to obtain a mixture;

(2) and (2) feeding the mixture obtained in the step (1) into a double-screw extruder from a main feeding port, injecting IPPP into the extruder at the end of a conveying and melting section by using a liquid metering pump, adding a B flame retardant from a lateral feeding port, extruding and granulating to obtain the halogen-free flame-retardant TPU cable material.

Wherein the temperature of the conveying melting section of the double-screw extruder is 180 ℃, the temperature of the mixing section is 195 ℃, the temperature of the exhaust homogenizing section is 200 ℃, and the temperature of the extruder head is 215 ℃. The structure of each section of the double-screw extruder is schematically shown in figure 1.

Comparative example 1

The comparative example is different from example 1 only in that MAH-g-SEBS is not included in the raw materials, and other materials and the mixture ratio are shown in Table 1.

Comparative example 2

This comparative example differs from example 1 only in that the preparation starting materials do not include a hydroxide smoke suppressant, and the other materials and proportions are shown in Table 1.

Comparative example 3

The comparative example is different from example 1 only in that the traditional diethyl aluminum hypophosphite and melamine cyanurate system is adopted to replace the flame retardant A and the flame retardant B in the preparation raw materials, the total part of the diethyl aluminum hypophosphite and the melamine cyanurate is 25 parts, the materials are fed from a side feeding port of a double screw extruder in the preparation process, and other materials and the mixture ratio are shown in Table 1.

Comparative example 4

The comparative example is different from example 1 only in that the traditional diethyl aluminum hypophosphite and melamine cyanurate system is adopted to replace the flame retardant A and the flame retardant B in the preparation raw materials, the total part of the diethyl aluminum hypophosphite and the melamine cyanurate is 35 parts, the materials are fed from a side feeding port of a double screw extruder in the preparation process, and other materials and the mixture ratio are shown in Table 1.

Comparative example 5

This comparative example differs from example 1 only in that the flame retardant DMMP A was not included in the raw materials for preparation, and the other materials and compounding ratios are shown in Table 1.

Comparative example 6

This comparative example differs from example 1 only in that the flame retardant B was not included in the raw materials for preparation, and the other materials and compounding ratios are shown in Table 1.

TABLE 1

Raw materials	Comparative example 1	Comparative example 2	Comparative example 3	Comparative example 4	Comparative example 5	Comparative example 6
							Polyether type TPU	68	64	66	56	62	62
DMMP	11	11	-	-	-	29
							B flame retardant	18	18	-	-	29	-
Diethyl aluminium hypophosphite	-	-	15	20	-	-
							Melamine cyanurate	-	-	10	15	-	-
MAH-g-SEBS	-	6	6	6	6	6
							Hydroxide compound	2	-	2	2	2	2
Silicone powder	0.5	0.5	0.5	0.5	0.5	0.5
							Antioxidant 1010	0.5	0.5	0.5	0.5	0.5	0.5

The halogen-free flame retardant TPU cable materials of examples 1 to 7 and comparative examples 1 to 6 were tested for their performance according to the following test methods:

(1) performing hardness test by using GB/T531-2009;

(2) testing the mechanical property by GB/T528-2009;

(3) and carrying out flame retardant property test by using UL-94.

The results of the performance tests are shown in table 2.

TABLE 2

	Hardness (shA)	Tensile Strength (MPa)	Elongation (%)	Amount of raw smoke	Flame retardancy
						Example 1	85	17.2	521	Chinese character shao (a Chinese character of 'shao')	V-0
Example 2	85	18.4	545	Chinese character shao (a Chinese character of 'shao')	V-1
						Example 3	85	17.8	536	Chinese character shao (a Chinese character of 'shao')	V-0
Example 4	85	17.5	530	Chinese character shao (a Chinese character of 'shao')	V-0
						Example 5	85	17.6	532	Chinese character shao (a Chinese character of 'shao')	V-0
Example 6	85	17.2	520	Chinese character shao (a Chinese character of 'shao')	V-0
						Example 7	85	18.0	544	Chinese character shao (a Chinese character of 'shao')	V-1
Comparative example 1	86	16.9	498	Chinese character shao (a Chinese character of 'shao')	V-0
						Comparative example 2	86	17.3	523	Multiple purpose	V-0
Comparative example 3	87	14.5	505	Chinese character shao (a Chinese character of 'shao')	V-2
						Comparative example 4	87	12.1	475	Multiple purpose	V-0
Comparative example 5	87	11.5	425	Chinese character shao (a Chinese character of 'shao')	V-1
						Comparative example 6	84	10.6	395	Chinese character shao (a Chinese character of 'shao')	V-1

As can be seen from Table 2, compared with example 1, the hardness, tensile strength, elongation and smoke generation of the low smoke zero halogen flame retardant TPU cable materials prepared in examples 2-7 have no obvious difference basically, and the flame retardancy of examples 2 and 7 is slightly reduced due to the addition of too little flame retardant.

Compared with example 1, the elongation of the TPU cable material of comparative example 1 is obviously reduced, and other parameters are not obviously changed, because the raw materials for preparing comparative example 1 do not comprise the compatilizer MAH-g-SEBS.

The TPU cable material of comparative example 2 had a significantly increased smoke generation compared to example 1, and the other parameters did not change significantly because the smoke suppressant was not included in the raw materials for the preparation of comparative example 2.

The TPU cable material of comparative example 3 has lower tensile strength, lower elongation and a flame retardant rating of V-2 compared to example 1.

Compared with the example 1, the TPU cable material of the comparative example 4 has the flame retardance reaching V-0, but other properties are seriously reduced, and the smoke generation amount is large.

The mechanical properties of the TPU cable material of comparative example 5 were severely degraded compared to example 1 and the flame retardant rating was V-1 because only a single B flame retardant was added in comparative example 5.

The TPU cable material of comparative example 6 has a reduced hardness compared to example 1 and a flame retardant rating of V-1 because only a single a flame retardant DMMP is added in comparative example 6.

In conclusion, the organic silicon hybrid polymer hydrophobic modifier is adopted to modify the aluminum hypophosphite and the melamine cyanurate, so that the flame-retardant system obtains hydrophobicity, and simultaneously, a large number of polar groups are introduced to the surface, thereby being beneficial to improving the water resistance, compatibility and precipitation resistance of the cable material and reducing the loss of the mechanical property of the material. The liquid phosphate flame retardant is used for replacing part of powder flame retardant, the liquid phosphate flame retardant is injected by a liquid metering pump at the tail end of a melting and mixing section of an extruder, the using amount of the powder flame retardant is reduced, the phosphate flame retardant is added after the TPU is completely melted, the compatibility is good, the phenomenon that all raw materials are mixed unevenly is reduced, the precipitation resistance is good, and the product quality of the TPU cable material is ensured.

The applicant states that the invention is illustrated by the above examples to the halogen-free flame retardant TPU cable material and the preparation method thereof, but the invention is not limited to the above examples, i.e. it does not mean that the invention must be implemented by the above examples. It will be apparent to those skilled in the art that any modification of the present invention, equivalent substitutions of selected materials and additions of auxiliary components, selection of specific modes and the like, which are within the scope and disclosure of the present invention, are contemplated by the present invention.

Claims

1. The halogen-free flame-retardant TPU cable material is characterized in that the preparation raw materials of the halogen-free flame-retardant TPU cable material comprise the following components in parts by weight:

2. The halogen-free flame retardant TPU cable material of claim 1 wherein the thermoplastic polyurethane elastomer is any one or a combination of at least two of a polyether TPU, a polyester TPU or a PCL TPU;

preferably, the hardness of the thermoplastic polyurethane elastomer is 85A-95A.

3. The halogen-free flame retardant TPU cable material of claim 1 or 2 wherein the A flame retardant is any one or a combination of at least two of dimethyl methyl phosphate, tri (dimethylphenyl) phosphate, cresyldiphenyl phosphate, triisopropylphenyl phosphate or Fyrol-A710 phosphorus based flame retardants.

4. The halogen free flame retardant TPU cable material of any of claims 1 to 3 wherein the B flame retardant is aluminum hypophosphite and melamine cyanurate modified with a hydrophobic modifier;

preferably, the hydrophobic modifier is a silicone hybrid polymer;

preferably, the silicone hybrid polymer is a controlled radical type silane hyperdispersant;

drying and then mixing aluminum hypophosphite and melamine cyanurate, adding a hydrophobic modifier to the surface of the mixture, and stirring and mixing to obtain the flame retardant B;

preferably, the mass ratio of the aluminum hypophosphite to the melamine cyanurate is (0.8-1.2) to (1.8-2.2);

preferably, the drying is carried out in an oven at 100-110 ℃;

preferably, the drying time is 2-3 h;

preferably, the stirring speed of the stirring and mixing is 800-1000 rpm;

preferably, after the temperature of the high-speed mixer is heated to 80-100 ℃, stopping heating, adding a mixture of aluminum hypophosphite and melamine cyanurate and a hydrophobic modifier, and stopping stirring when the temperature of the high-speed mixer rises to 110-120 ℃;

5. The halogen-free flame retardant TPU cable material of any one of claims 1 to 4 wherein the compatibilizer is one or a combination of at least two of maleic anhydride grafted ethylene vinyl acetate copolymer, maleic anhydride grafted polyethylene, or maleic anhydride grafted styrene-ethylene-butylene-styrene block copolymer.

6. The halogen-free flame retardant TPU cable material of any one of claims 1 to 5 wherein the smoke suppressant is any one or a combination of at least two of a hydroxide, a molybdenum compound, a magnesium-zinc compound, a magnesium-aluminum compound, or an iron compound.

7. The halogen-free flame retardant TPU cable material of any one of claims 1 to 6 wherein the halogen-free flame retardant TPU cable material further comprises 0.5 to 1 part by weight of a lubricant;

preferably, the lubricant is any one or combination of at least two of stearate, erucamide, polyethylene wax or silicone powder;

preferably, the halogen-free flame-retardant TPU cable material further comprises 0.5-1 part by weight of an antioxidant;

preferably, the antioxidant is pentaerythritol tetrakis [ beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate ].

8. The preparation method of halogen free flame retardant TPU cable material according to any of claims 1 to 7, characterized in that the preparation method comprises the following steps:

9. The preparation method according to claim 8, wherein the mixing time in the step (1) is 10-15 min;

preferably, the A flame retardant of step (2) is injected with a liquid metering pump;

preferably, the temperature of the conveying melting section of the double-screw extruder is 160-190 ℃, the temperature of the mixing section is 170-195 ℃, the temperature of the exhaust homogenizing section is 175-200 ℃, and the temperature of the head of the extruder is 205-215 ℃.

10. Use of the halogen free flame retardant TPU cable material according to any of claims 1-7 in the preparation of cables, shoe materials or medical materials.