CN106220808B - A kind of thermoplastic polyurethane elastomer resistant to bending and preparation method thereof - Google Patents

Abstract

The present invention provides a kind of thermoplastic polyurethane elastomer resistant to bending and preparation method thereof, the thermoplastic polyurethane elastomer is mainly prepared by following raw material: 20-40 parts by weight diisocyanate, 50-65 weight of polyester dihydric alcohol, 20-30 weight account polyethylene alcohol resin, 10-20 parts by weight of polypropylene, 1-5 parts by weight chain extender and 1-3 part by weight of catalyst, the polyurethane elastomer hardness that the present invention obtains is 38-43A, tensile strength reaches 82MPa or more, elongation at break reaches 680%, rebound degree reaches 85% or more, with good elasticity, moderate hardness, ability resistant to bending is good, machinability is strong.

Description

A kind of bending-resistant thermoplastic polyurethane elastomer and its preparation method

technical field

The invention belongs to the field of polymer materials, and relates to a bending-resistant thermoplastic polyurethane elastomer and a preparation method thereof.

Background technique

Thermoplastic polyurethane (TPU) is a new type of organic polymer synthetic material with excellent properties and can replace rubber and soft polyvinyl chloride material PVC. For example, it has excellent physical properties, such as wear resistance and resilience, which are better than ordinary polyurethane and PVC, and aging resistance is better than rubber. It can be said to be the most ideal material to replace PVC and PU.

With the further development of science and technology, various fields put forward higher requirements for the high strength and bending resistance of materials. CN105111663A discloses a new type of data line sheathing material with high strength and bending resistance, which is made of the following raw materials in parts by weight Composition: SEBS100-104, paraffin oil 65-68, polypropylene 29-31, polypropylene grafted maleic anhydride 21-23, antioxidant B215 3-4, magnesium hydroxide 81-83, expanded graphite 4.3-5, Silane coupling agent A-171 1.6-1.7, absolute ethanol 8-9, antimony trioxide 5-7, micron calcium carbonate 4.5-6, water-based polyurethane resin 2-3, nylon 11 10-12 and polyisocyanate 1- 1.3. The product prepared by this invention has bending resistance and good flame retardant effect, and can be used for data lines, earphone lines, etc. However, this invention relies on multiple components to obtain the bending-resistant material, and the components are complex.

With the development of some more high-end products, higher requirements for bending resistance are put forward for materials. Therefore, in this field, it is expected to obtain a polyurethane elastomer material with relatively simple components and simple and practical preparation process.

Contents of the invention

In view of the deficiencies of the prior art, the object of the present invention is to provide a bending-resistant thermoplastic polyurethane elastomer and a preparation method thereof. The thermoplastic polyurethane elastomer of the present invention has good elasticity and mechanical strength, and good bending resistance.

For reaching this purpose, the present invention adopts following technical scheme:

In one aspect, the present invention provides a bending-resistant thermoplastic polyurethane elastomer, which is mainly prepared from the following raw materials:

Wherein said diisocyanate is a mixture of toluene diisocyanate and hexamethylene diisocyanate.

In the present invention, the ratio of soft segment to hard segment can be well controlled by selecting polyester diol in combination with two specific diisocyanates and a specific amount of other ingredients, so that the hardness of the polyurethane elastomer is moderate , to obtain products with ideal elasticity and bending resistance.

In the present invention, the diisocyanate can be used in an amount of 22 parts by weight, 24 parts by weight, 26 parts by weight, 28 parts by weight, 30 parts by weight, 33 parts by weight, 35 parts by weight or 38 parts by weight.

In the present invention, the polyester diol may be used in an amount of 51 parts by weight, 53 parts by weight, 55 parts by weight, 57 parts by weight, 59 parts by weight, 61 parts by weight, 63 parts by weight or 64 parts by weight.

In the present invention, the amount of the polyvinyl alcohol resin can be 21 parts by weight, 22 parts by weight, 23 parts by weight, 24 parts by weight, 25 parts by weight, 26 parts by weight, 27 parts by weight, 28 parts by weight or 29 parts by weight .

In the present invention, the polypropylene may be used in an amount of 11 parts by weight, 12 parts by weight, 13 parts by weight, 14 parts by weight, 15 parts by weight, 16 parts by weight, 17 parts by weight, 18 parts by weight or 19 parts by weight.

In the present invention, the amount of the chain extender can be 1.3 parts by weight, 1.5 parts by weight, 1.8 parts by weight, 2 parts by weight, 2.3 parts by weight, 2.5 parts by weight, 2.8 parts by weight, 3 parts by weight, 3.5 parts by weight, 3.8 parts by weight, 4 parts by weight, 4.5 parts by weight or 4.8 parts by weight.

In the present invention, the catalyst can be used in an amount of 1.3 parts by weight, 1.5 parts by weight, 1.8 parts by weight, 2 parts by weight, 2.3 parts by weight, 2.5 parts by weight or 2.8 parts by weight.

Preferably, the polyurethane elastomer is mainly prepared from the following raw materials:

In the present invention, the mass ratio of toluene diisocyanate and hexamethylene diisocyanate in the diisocyanate is (3-8):1, such as 3:1, 3.5:1, 4:1, 4.5:1, 5:1, 5.5 :1, 6:1, 6.5:1, 7:1, 7.5:1 or 8:1, preferably (4-6):1.

Preferably, the polyester diol is polyethylene adipate diol and/or polypropylene adipate diol.

Preferably, the polyester diol has a number average molecular weight of 1500-3000, such as 1500, 1800, 2000, 2200, 2400, 2600, 2800 or 3000. In the present invention, the selection of the number-average molecular weight of the polyester diol has a certain influence on the elastic properties of the polyurethane elastomer. When the number-average molecular weight is less than 3000, since the hard segment of the polyurethane elastomer accounts for a large proportion, the product has high hardness and poor bendability.

Preferably, the polypropylene has a number average molecular weight of 3000-5000, such as 3000, 3300, 3500, 3800, 4000, 4200, 4500, 4800 or 5000.

Preferably, the chain extender is any one or a combination of at least two of ethylene glycol, 1,3-propanediol, 1,4-butanediol or 1,5-pentanediol.

Preferably, the catalyst is any one or a combination of at least two of stannous octoate, dibutyltin dioctoate or dibutyltin laurate.

In the present invention, the polyvinyl alcohol resin and polypropylene can act synergistically to further enhance the bending resistance of the material, so that the final product has good elasticity, good bending resistance and good processability.

In another aspect, the present invention provides a method for preparing the bending-resistant thermoplastic polyurethane elastomer as described in 7 above, the method comprising the following steps:

(1) Add diisocyanate, polyester diol, polyvinyl alcohol resin, polypropylene, chain extender and catalyst into the container, dehydrate under vacuum under stirring conditions, and then dehydrate at 120-140°C (for example, 123°C, 125°C ℃, 128°C, 130°C, 132°C, 135°C or 138°C) for 1-5h (such as 1.3h, 1.5h, 1.8h, 2h, 2.3h, 2.5h, 3h, 3.5h, 4h, 4.5h or 4.8h);

(2) Add polyvinyl alcohol resin and polypropylene to the reaction material in step (1), and after mixing uniformly, extrude and granulate with a twin-screw extruder to obtain the bending-resistant thermoplastic polyurethane elastomer.

Preferably, the temperature during vacuum dehydration in step (1) is 60-80°C, such as 62°C, 65°C, 68°C, 70°C, 72°C, 74°C, 76°C or 78°C.

Preferably, the stirring rate in step (1) is 1200-1500r/min, such as 1200r/min, 1250r/min, 1300r/min, 1350r/min, 1400r/min, 1450r/min or 1500r/min.

Preferably, the pressure during vacuum dehydration in step (1) is -0.3～-0.1kPa, such as -0.3kPa, -0.28kPa, -0.25kPa, -0.23kPa, -0.2kPa, -0.18kPa, -0.15kPa , -0.13kPa or -0.1kPa.

Preferably, the temperature of the feeding section of the twin-screw extruder in step (2) is 100-120°C, such as 105°C, 108°C, 110°C, 115°C or 118°C, and the temperature of the mixing section is 140-150°C, For example, 142°C, 144°C, 146°C or 148°C, the temperature of the extrusion section is 170-190°C, such as 172°C, 175°C, 178°C, 180°C, 183°C, 185°C or 188°C, and the temperature of the die head is 150°C -180°C, eg 153°C, 155°C, 158°C, 160°C, 165°C, 168°C, 170°C, 175°C or 178°C.

As a preferred technical solution, the preparation method of the bending-resistant thermoplastic polyurethane elastomer of the present invention specifically includes the following steps:

(1) Put diisocyanate, polyol, chain extender and catalyst into the container, stir at 1200-1500r/min, dehydrate in vacuum at 60-80℃ under pressure of -0.3～-0.1kPa, and then dehydrate at 120 Reaction at -140℃ for 1-5h;

(2) Add polyvinyl alcohol resin to the reaction material of step (1), after mixing evenly, utilize a twin-screw extruder to extrude and granulate, and the temperature of the feeding section of the twin-screw extruder is 100-120°C , the temperature of the mixing section is 140-150°C, the temperature of the extrusion section is 170-190°C, and the temperature of the machine head is 150-180°C, and the bending-resistant thermoplastic polyurethane elastomer is obtained after extrusion and granulation.

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

The present invention adopts polyester diol and specific two kinds of diisocyanates to be used together, and cooperates specific amount of other components, can well control the ratio of soft segment and hard segment, make the hardness of polyurethane elastomer moderate, obtain comparative Ideal for elastic, flex-resistant products, where polyvinyl alcohol resin and polypropylene have a synergistic effect on improving the flex resistance of the material. The polyurethane elastic body obtained by the present invention has a hardness of 38-43A, a tensile strength of more than 82MPa, an elongation at break of 680%, and a rebound rate of more than 85%. It has good elasticity, moderate hardness, and good bending resistance. , Strong machinability.

Detailed ways

The technical solutions of the present invention will be further described below through specific embodiments. It should be clear to those skilled in the art that the embodiments are only for helping to understand the present invention, and should not be regarded as specific limitations on the present invention.

Example 1

In this embodiment, the thermoplastic polyurethane elastomer is prepared from the following raw materials:

Wherein said diisocyanate is the mixture of toluene diisocyanate and hexamethylene diisocyanate, and the mass ratio of toluene diisocyanate and hexamethylene diisocyanate is 4:1; Polyester diol is polyethylene adipate diol, and its number average molecular weight It is 3000; the number average molecular weight of polypropylene is 3000.

The preparation method is as follows:

(1) Add diisocyanate, polyol, chain extender, and catalyst into the container, stir at 1500r/min, vacuum dehydrate at 70°C under the pressure of -0.1kPa, and then react at 130°C for 4 hours;

(2) Add polyvinyl alcohol resin to the reaction mass of step (1), after mixing uniformly, utilize a twin-screw extruder to extrude and granulate. The temperature of the feeding section of the twin-screw extruder is 100° C., mix The section temperature is 140°C, the extrusion section temperature is 180°C, and the head temperature is 150°C, and the bending-resistant thermoplastic polyurethane elastomer is obtained after extrusion and granulation.

Example 2

In this embodiment, the thermoplastic polyurethane elastomer is prepared from the following raw materials:

Wherein said diisocyanate is the mixture of toluene diisocyanate and hexamethylene diisocyanate, and the mass ratio of toluene diisocyanate and hexamethylene diisocyanate is 3:1; Polyester diol is polyethylene adipate diol, and its number average molecular weight It is 2000; the number average molecular weight of polypropylene is 5000.

The preparation method is as follows:

(1) Add diisocyanate, polyol, chain extender, and catalyst into the container, stir at 1300r/min, vacuum dehydrate at 80°C under the pressure of -0.3kPa, and then react at 140°C for 1 hour;

(2) Add polyvinyl alcohol resin to the reaction mass of step (1), after mixing uniformly, utilize twin-screw extruder to extrude and granulate, the temperature of the feeding section of the twin-screw extruder is 120 DEG C, mix The section temperature is 150°C, the extrusion section temperature is 170°C, and the head temperature is 150°C, and the bending-resistant thermoplastic polyurethane elastomer is obtained after extrusion and granulation.

Example 3

In this embodiment, the thermoplastic polyurethane elastomer is prepared from the following raw materials:

Wherein said diisocyanate is the mixture of toluene diisocyanate and hexamethylene diisocyanate, and the mass ratio of toluene diisocyanate and hexamethylene diisocyanate is 8:1; Polyester diol is polyethylene adipate diol, and its number average molecular weight It is 1500; the number average molecular weight of polypropylene is 4000.

The preparation method is as follows:

(1) Add diisocyanate, polyol, chain extender, and catalyst into the container, stir at 1200r/min, vacuum dehydrate at 60°C under the pressure of -0.2kPa, and then react at 120°C for 5h;

(2) Add polyvinyl alcohol resin to the reaction mass of step (1), after mixing uniformly, utilize a twin-screw extruder to extrude and granulate. The temperature of the feeding section of the twin-screw extruder is 110° C. The section temperature is 145°C, the extrusion section temperature is 190°C, and the head temperature is 180°C, and the bending-resistant thermoplastic polyurethane elastomer is obtained after extrusion and granulation.

Example 4

In this embodiment, the thermoplastic polyurethane elastomer is prepared from the following raw materials:

Wherein said diisocyanate is the mixture of toluene diisocyanate and hexamethylene diisocyanate, and the mass ratio of toluene diisocyanate and hexamethylene diisocyanate is 5:1; Polyester diol is polytrimethylene adipate diol, and its number average molecular weight is 2000 ; The number average molecular weight of polypropylene is 4000.

The preparation method is as follows:

(1) Add diisocyanate, polyol, chain extender, and catalyst into the container, stir at 1200r/min, vacuum dehydrate at 60°C under the pressure of -0.3kPa, and then react at 140°C for 3h;

(2) Add polyvinyl alcohol resin to the reaction mass of step (1), after mixing uniformly, utilize twin-screw extruder to extrude and granulate, the temperature of the feeding section of the twin-screw extruder is 120 DEG C, mix The section temperature is 150°C, the extrusion section temperature is 190°C, and the head temperature is 170°C, and the bending-resistant thermoplastic polyurethane elastomer is obtained after extrusion and granulation.

Comparative example 1

The only difference between this comparative example and Example 1 is that the diisocyanate is an independent toluene diisocyanate, except that, all the other raw materials, raw material consumption and preparation method are the same as in Example 1.

Comparative example 2

The only difference between this comparative example and Example 1 is that the diisocyanate is a single hexamethylene diisocyanate, except that all the other raw materials, raw material consumption and preparation method are the same as in Example 1.

Comparative example 3

The only difference between this comparative example and Example 1 is that the mass ratio of toluene diisocyanate to hexamethylene diisocyanate is 2:1, other than that, the rest of the raw materials, the amount of raw materials and the preparation method are the same as in Example 1.

Comparative example 4

The only difference between this comparative example and Example 1 is that the mass ratio of toluene diisocyanate to hexamethylene diisocyanate is 9:1, other than that, the rest of the raw materials, the amount of raw materials and the preparation method are the same as in Example 1.

Comparative example 5

The only difference between this comparative example and Example 1 is that the number-average molecular weight of the polyester diol is 1000, except that, all the other raw materials, raw material consumption and preparation method are the same as in Example 1.

Comparative example 6

The only difference between this comparative example and Example 1 is that the number-average molecular weight of the polyester diol is 3500, except that, the rest of the raw materials, raw material consumption and preparation method are the same as in Example 1.

Comparative example 7

The only difference between this comparative example and Example 1 is that polyvinyl alcohol resin and polypropylene are not included in the raw materials for the preparation of thermoplastic polyurethane elastomers. In addition, all the other raw materials, raw material consumption and preparation method are the same as those in Example 1. same.

Comparative example 8

The only difference between this comparative example and Example 1 is that polyvinyl alcohol resin is not included in the raw materials for the preparation of thermoplastic polyurethane elastomers, and the amount of polypropylene is 39 parts by weight. All the same as in Example 1.

Comparative example 9

The only difference between this comparative example and Example 1 is that polypropylene is not included in the raw materials for the preparation of thermoplastic polyurethane elastomers, and the amount of polyvinyl alcohol resin is 39 parts by weight. In addition, the remaining raw materials and raw material consumption and preparation method All the same as in Example 1.

The performance tests of the polyurethane elastomers prepared in Examples 1-4 and Comparative Examples 1-9 are shown in Table 1.

Table 1

As can be seen from the results in Table 1, the hardness of the polyurethane elastomer obtained by the present invention is 38-43A, the tensile strength reaches more than 82MPa, the elongation at break reaches 680%, and the rebound rate reaches more than 85%, and has good elasticity. Moderate hardness, good bending resistance and strong machinability. And it can be seen from the comparison between Example 1 and Comparative Examples 7-9 that the polyvinyl alcohol resin and polypropylene used in the present invention have a synergistic effect on further improving the bending resistance of the material.

The applicant declares that the present invention illustrates the bending-resistant thermoplastic polyurethane elastomer of the present invention and its preparation method through the above examples, but the present invention is not limited to the above examples, that is, it does not mean that the present invention must rely on the above examples to achieve implement. Those skilled in the art should understand that any improvement of the present invention, the equivalent replacement of each raw material of the product of the present invention, the addition of auxiliary components, the selection of specific methods, etc., all fall within the scope of protection and disclosure of the present invention.

Claims (14)

1. a bending-resistant thermoplastic polyurethane elastomer, is characterized in that, described polyurethane elastomer is prepared by following raw material: 20-40 parts by weight of diisocyanate 50-65 parts by weight of polyester diol 20-30 parts by weight of polyvinyl alcohol resin 10-20 parts by weight of polypropylene Chain extender 1-5 parts by weight Catalyst 1-3 parts by weight; The diisocyanate is a mixture of toluene diisocyanate and hexamethylene diisocyanate, and the mass ratio of toluene diisocyanate to hexamethylene diisocyanate in the diisocyanate is (3-8):1. 2. The bending-resistant thermoplastic polyurethane elastomer according to claim 1, wherein the polyurethane elastomer is prepared from the following raw materials: 35 parts by weight of diisocyanate 55 parts by weight of polyester diol 24 parts by weight of polyvinyl alcohol resin 15 parts by weight of polypropylene Chain extender 2 parts by weight Catalyst 2 parts by weight. 3 . The bending-resistant thermoplastic polyurethane elastomer according to claim 1 , wherein the mass ratio of toluene diisocyanate to hexamethylene diisocyanate in the diisocyanate is (4-6):1. 4. The bending-resistant thermoplastic polyurethane elastomer according to claim 1, wherein the polyester diol is polyethylene adipate diol and/or polypropylene adipate diol. 5. The bending-resistant thermoplastic polyurethane elastomer according to claim 1, characterized in that the number average molecular weight of the polyester diol is 1000-3000. 6. The bending-resistant thermoplastic polyurethane elastomer according to claim 1, characterized in that the number average molecular weight of the polypropylene is 3000-5000. 7. The bending-resistant thermoplastic polyurethane elastomer according to claim 1, wherein the chain extender is ethylene glycol, 1,3-propanediol, 1,4-butanediol or 1,5-pentanediol Any one or a combination of at least two diols. 8. The bending-resistant thermoplastic polyurethane elastomer according to claim 1, wherein the catalyst is any one or a combination of at least two of stannous octoate, dibutyltin dioctoate or dibutyltin laurate . 9. The preparation method of the bending-resistant thermoplastic polyurethane elastomer according to any one of claims 1-8, characterized in that, the method comprises the following steps: (1) Add diisocyanate, polyester diol, polyvinyl alcohol resin, polypropylene, chain extender and catalyst into the container, vacuum dehydrate under stirring condition, and then react at 120-140°C for 1-5h; (2) Add polyvinyl alcohol resin and polypropylene to the reaction material in step (1), and after mixing evenly, use a twin-screw extruder to extrude and granulate to obtain the bending-resistant thermoplastic polyurethane elastomer. 10. The preparation method according to claim 9, characterized in that the temperature during the vacuum dehydration in step (1) is 60-80°C. 11. The preparation method according to claim 9, characterized in that the stirring rate in step (1) is 1200-1500 r/min. 12. The preparation method according to claim 9, characterized in that the pressure during the vacuum dehydration in step (1) is -0.3-0.1kPa. 13. The preparation method according to claim 9, characterized in that the temperature of the feeding section of the twin-screw extruder in step (2) is 100-120°C, the temperature of the mixing section is 140-150°C, and the extrusion section The temperature is 170-190°C, and the head temperature is 150-180°C. 14. preparation method according to claim 9 is characterized in that, described method comprises the following steps: (1) Put diisocyanate, polyol, chain extender and catalyst into the container, stir at 1200-1500 r/min, dehydrate in vacuum at 60-80℃ under pressure of -0.3～-0.1kPa, and then Reaction at 120-140°C for 1-5h; (2) Add polyvinyl alcohol resin to the reaction material in step (1), and after mixing evenly, use a twin-screw extruder to extrude and granulate. The temperature of the feeding section of the twin-screw extruder is 100-120°C , the temperature of the mixing section is 140-150°C, the temperature of the extrusion section is 170-190°C, and the temperature of the machine head is 150-180°C, and the bending-resistant thermoplastic polyurethane elastomer is obtained after extrusion and granulation.