A high-resilience low-melting thermoplastic polyurethane elastomer, and a method of making and using the same

Abstract

The present application belongs to the field of polyurethane elastomer, and particularly relates to a high-resilience low-melting-point thermoplastic polyurethane elastomer and a preparation method and application thereof, which is prepared from raw materials comprising the following weight parts: polyol 65-85 parts; diisocyanate 13-23 parts; chain extender 2-12 parts; wherein the chain extender is a mixture of t-butyl diamine derivative and dihydric alcohol. The present application introduces t-butyl diamine derivative into the chain extender component, and is prepared by using a double-screw extruder in a one-step reaction under the synergistic effect of specific composition. The thermoplastic polyurethane elastomer has a 300% resilience retention rate of up to 95% or more, a melting point of 85-120 DEG C, and excellent bonding performance.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of polyurethane, and relates to a thermoplastic polyurethane elastomer and a preparation method and application. BACKGROUND

[0002] The thermoplastic polyurethane elastomer (TPU) is a block copolymer composed of polyol soft segment, isocyanate and chain extender hard segment, and has a performance between rubber and plastic. Therefore, through a special structure composition, elasticity like rubber and rigidity like plastic can be obtained. The shoe and clothing field has been one of the main application fields of TPU products, and with the improvement of people's living standards, the shoe and clothing industry has higher and higher requirements for high resilience, low processing temperature and high bonding strength of the material. The current mainstream high-resilience thermoplastic polyurethane product has a very high melting point (higher than 140 DEG C), and therefore a higher processing temperature is required to achieve better adhesion with the base material.

[0003] Patent WO2024038104 discloses a high-resilience low-softening-temperature thermoplastic polyurethane, which uses 3-methyl-1, 5-pentanediol as a polyol soft segment component and combines with hydroquinone dihydroxyethyl ether (HQEE) as a chain extender component to obtain a thermoplastic polyurethane elastomer with a softening point of 80-140 DEG C and a resilience (100% resilience retention rate) of more than 92% under certain composition. However, the thermoplastic polyurethane elastomer obtained by using 3-methyl-1, 5-pentanediol as a soft segment in the technical route has low strength, poor adhesion and limited resilience elongation. SUMMARY

[0004] In view of the above problems existing in the prior art, the purpose of the present application is to provide a high-resilience low-melting-point thermoplastic polyurethane elastomer, which solves the problem that the traditional high-resilience thermoplastic polyurethane elastomer is difficult to have high elasticity, low melting point and high adhesion performance at the same time.

[0005] To solve the above problems, the technical scheme adopted by the present application is as follows:

[0006] The present application provides a high-resilience low-melting-point thermoplastic polyurethane elastomer, which is prepared from raw materials containing the following weight parts:

[0007] 65-85 parts of polyol, for example, 65 parts, 68 parts, 70 parts, 72 parts, 75 parts, 78 parts, 80 parts, 82 parts, 85 parts, etc.

[0008] 13-23 parts of diisocyanate, for example, 13 parts, 15 parts, 18 parts, 20 parts, 22 parts, 23 parts, etc.

[0009] 2-12 parts of chain extender, for example, 2 parts, 4 parts, 6 parts, 8 parts, 10 parts, 12 parts, etc.

[0010] The chain extender is a mixture of tert-butyldiamine derivative and diol.

[0011] In one specific embodiment, the tert-butyldiamine derivative has the structure shown in Formula 1:

[0012]

[0013] In the formula, R is an alicyclic group of C5 to C7, preferably cyclopentyl, cyclohexyl, or cycloheptyl.

[0014] Preferably, the tert-butyldiamine derivative is selected from one or more of 4,4-(cyclohexylmethylene)bis(2-tert-butyl)aniline, 4,4-(cyclopentylmethylene)bis(2-tert-butyl)aniline, and 4,4-(cycloheptylmethylene)bis(2-tert-butyl)aniline.

[0015] In one specific embodiment, the polyol has a number-average molecular weight of 1500-4000 g / mol, such as 1500 g / mol, 2000 g / mol, 2500 g / mol, 3000 g / mol, 3500 g / mol, 4000 g / mol, etc.

[0016] Furthermore, the polyol has a hydroxyl value of 20-110 mgKOH / g, such as 20 mgKOH / g, 40 mgKOH / g, 60 mgKOH / g, 80 mgKOH / g, 100 mgKOH / g, 110 mgKOH / g, etc., and an acid value of 0-1 mgKOH / g, such as 0 KOH / g, 0.2 mgKOH / g, 0.4 mgKOH / g, 0.6 mgKOH / g, 0.8 mgKOH / g, 1 mgKOH / g, etc., preferably a hydroxyl value of 25-80 mgKOH / g and an acid value of 0-0.5 mgKOH / g;

[0017] Furthermore, the polyol may be any one or a combination of polyester polyol, polyether polyol, and polycaprolactone polyol.

[0018] Preferably, the polyester polyol is prepared by adipic acid and a diol through a well-known polyester polyol synthesis process; wherein the diol may be one or more of ethylene glycol, diethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, diethylene glycol, dipropylene glycol, and neopentyl glycol;

[0019] More preferably, the polyester polyol is one or more of polyhexanediol adipate, polyhexanediol adipate, and ethylene glycol butylene adipate.

[0020] Preferably, the polyether polyol is prepared by ring-opening polymerization of an epoxide compound using a compound containing active hydrogen as an initiator; wherein the epoxide compound can be one or more of propylene oxide, tetrahydrofuran, and ethylene oxide; and the compound containing active hydrogen can be one or more of ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, and bisphenol A.

[0021] More preferably, the polyether polyol is polytetrahydrofuran ether diol;

[0022] Preferably, the polycaprolactone polyol is prepared by ring-opening polymerization of ε-caprolactone initiated by a small molecule alcohol as an initiator using a method known in the industry; wherein the small molecule alcohol may be one or more of 1,4-butanediol, 1,6-hexanediol, dipropylene glycol, and neopentyl glycol;

[0023] More preferably, the polycaprolactone polyol is a neopentyl glycol-based polycaprolactone polyol.

[0024] In one specific embodiment, the diisocyanate component may be an aromatic diisocyanate, an aliphatic diisocyanate, or a combination thereof;

[0025] Furthermore, the aromatic diisocyanate includes one or more of 4,4-diphenylmethane diisocyanate, toluene diisocyanate, and terephthalic diisocyanate, preferably 4,4-diphenylmethane diisocyanate.

[0026] Furthermore, the aliphatic diisocyanate includes one or more of hexamethylene diisocyanate, 4,4-dicyclohexylmethane diisocyanate, isoflurone diisocyanate, and cyclohexanedimethylene diisocyanate, preferably hexamethylene diisocyanate.

[0027] In one specific embodiment, the mass ratio of the tert-butyldiamine derivative to the diol in the chain extender is (1-9):1, for example 1:1, 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, etc., preferably (3-6):1;

[0028] In the chain extender, the diol is selected from aliphatic diols, preferably one or more of ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, dipropylene glycol, and neopentyl glycol, more preferably 1,4-butanediol.

[0029] The present invention also provides a method for preparing the above-mentioned high-resilience, low-melting-point thermoplastic polyurethane elastomer.

[0030] The high-resilience, low-melting-point thermoplastic polyurethane elastomer can be prepared by the conventional blending extrusion method used in the field of thermoplastic polyurethane elastomers, such as a one-step reaction using a twin-screw extruder.

[0031] Specifically, a method for preparing a high-resilience, low-melting-point thermoplastic polyurethane elastomer includes the following steps:

[0032] The high-resilience, low-melting-point thermoplastic polyurethane elastomer is obtained by mixing polyol, diisocyanate and chain extender in a certain proportion, and then granulating by twin-screw reactive extrusion.

[0033] Preferably, the extruder temperature is 120–220°C and the screw speed is 180–220 RPM;

[0034] The granulation process is cooled to a temperature of 5–30°C.

[0035] For any related operations and process conditions not covered in the preparation method of this invention, as well as the apparatus used, conventional choices in the field can be adopted. Those skilled in the art can optimize the process based on existing technology and known processes according to actual needs, and there are no particular restrictions.

[0036] The thermoplastic polyurethane elastomer of the present invention has a 300% rebound retention rate of up to 95% or more, a melting point of 85-120°C, and excellent adhesion properties, making it suitable for clothing, footwear and other fields.

[0037] The features and effective results of this invention are as follows:

[0038] This invention relates to a thermoplastic polyurethane elastomer that uses a synergistic combination of a tert-butyl diamine derivative and a diol as a chain extender component. The aromatic diamine groups can form strong urea bonds with the isocyanate groups, resulting in high resilience. Simultaneously, the tert-butyl side chain structure, combined with the diol, weakens the crystallinity of the elastomer to some extent. The synergistic effect of these components yields a low-melting-point, high-resilience thermoplastic polyurethane elastomer, which also possesses excellent adhesive properties, making it particularly suitable for the footwear and apparel industry. Detailed Implementation

[0039] The following embodiments will further illustrate the method provided by the present invention, but the present invention is not limited to the listed embodiments, and should also include any other known modifications within the scope of the claims of the present invention.

[0040] The main raw materials used in the various embodiments and comparative examples of this invention are as follows. Unless otherwise specified, other raw materials and reagents were obtained through commercially available channels:

[0041] Polyester polyols (Wanhua Chemical):

[0042] Poly(hexanediol butylene adipate) (PBHA, number average molecular weight 2000, hydroxyl value 56 mg KOH / g, acid value 0.2 mg KOH / g),

[0043] Polyhexyl adipate (PHA, number average molecular weight 1500, hydroxyl value 74.8 mgKOH / g, acid value 0.2 mgKOH / g),

[0044] Polyethylene glycol butylene adipate (PEBA, number average molecular weight 4000, hydroxyl value 28 mgKOH / g, acid value 0.1 mgKOH / g),

[0045] Poly(1,5-pentanediol adipate) (PMA, number average molecular weight 3000), hydroxyl value 37.5 mg KOH / g, acid value 0.1 mg KOH / g.

[0046] Poly(hexanediol butylene adipate) (PBHA, number average molecular weight 1500, hydroxyl value 75 mg KOH / g, acid value 0.2 mg KOH / g),

[0047] Poly(3-methyl-1,5-pentanediol adipate) (PM3A, number-average molecular weight 4000, hydroxyl value 28 mgKOH / g, acid value 0.1 mgKOH / g);

[0048] Polyether polyols (BASF): Polytetrahydrofuran ether diol (PTMEG, number average molecular weight 2000, hydroxyl value 56 mg KOH / g, acid value 0.15 mg KOH / g);

[0049] Polycaprolactone diol (Hunan Juren): Polycaprolactone diol (PCL, initiator NPG, number average molecular weight 2000, hydroxyl value 56mgKOH / g, acid value 0.1mgKOH / g);

[0050] Isocyanate (Wanhua Chemical):

[0051] 4,4-Diphenylmethane diisocyanate (MDI)

[0052] Hexamethylene diisocyanate (HDI);

[0053] Aromatic alcohol chain extender (Eastman, USA): Hydroquinone dihydroxyethyl ether (HQEE);

[0054] tert-Butyl diamine chain extender (prepared according to the method disclosed in patent CN 108383733 A):

[0055] 4,4-(cyclohexylmethylene)bis(2-tert-butyl)aniline,

[0056] 4,4-(cyclopentylmethylene)bis(2-tert-butyl)aniline,

[0057] 4,4-(cycloheptylmethylene)bis(2-tert-butyl)aniline;

[0058] Diols (Wanhua Chemical): 1,4-Butanediol, Neopentyl glycol;

[0059] 4,4-Methylenebis(2,6-diisopropyl)aniline (M-DIPA) (Jiangsu Kunshan Chemical Raw Materials Co., Ltd.)

[0060] Example 1

[0061] A high-resilience, low-melting-point thermoplastic polyurethane elastomer, the raw material composition by weight is as follows:

[0062] A) 75 parts of polyol: Poly(hexanediol butylene adipate) (PBHA), number average molecular weight 3000 g / mol.

[0063] B) 16 parts of diisocyanate: 4,4-diphenylmethane diisocyanate.

[0064] C) Chain extender 9 parts: tert-butyldiamine derivative (R is cyclohexyl) 4,4-(cyclohexylmethylene)bis(2-tert-butyl)aniline and 1,4-butanediol, in a weight ratio of 3:1.

[0065] The above components are mixed evenly and added to a twin-screw extruder for reaction extrusion to obtain thermoplastic polyurethane elastomer. The extrusion temperature is 200℃, the screw speed is 200RPM, and the granulation process is cooled to 10℃.

[0066] Example 2

[0067] A high-resilience, low-melting-point thermoplastic polyurethane elastomer, the raw material composition by weight is as follows:

[0068] A) 72 parts of polyol: polycaprolactone diol (PCL), number average molecular weight 3000 g / mol.

[0069] B) 18 parts of diisocyanate: 4,4-diphenylmethane diisocyanate.

[0070] C) Chain extender 10 parts: tert-butyldiamine derivative (R is cyclohexyl) 4,4-(cyclohexylmethylene)bis(2-tert-butyl)aniline and 1,4-butanediol, in a weight ratio of 5:1.

[0071] The above components are mixed evenly and added to a twin-screw extruder for reaction extrusion to obtain thermoplastic polyurethane elastomer. The extrusion temperature is 220℃, the screw speed is 210RPM, and the granulation process is cooled to 10℃.

[0072] Example 3

[0073] A high-resilience, low-melting-point thermoplastic polyurethane elastomer, the raw material composition by weight is as follows:

[0074] A) 70 parts of polyol: polytetrahydrofuran ether diol (PTMEG), number average molecular weight 2000 g / mol.

[0075] B) 20 parts of diisocyanate: hexamethylene diisocyanate.

[0076] C) Chain extender 10 parts: tert-butyldiamine derivative (R is cyclopentyl) 4,4-(cyclopentylmethylene)bis(2-tert-butyl)aniline and neopentyl glycol, in a weight ratio of 5:1.

[0077] The above components are mixed evenly and added to a twin-screw extruder for reactive extrusion to obtain thermoplastic polyurethane elastomer. The extrusion temperature is 190℃, the screw speed is 200RPM, and the granulation process is cooled to 10℃.

[0078] Example 4

[0079] A high-resilience, low-melting-point thermoplastic polyurethane elastomer, the raw material composition by weight is as follows:

[0080] A) 65 parts of polyol: Polyhexyl adipate (PHA), number average molecular weight 1500 g / mol.

[0081] B) 23 parts of diisocyanate: hexamethylene diisocyanate.

[0082] C) Chain extender 12 parts: tert-butyldiamine derivative (R is cyclopentyl) 4,4-(cyclopentylmethylene)bis(2-tert-butyl)aniline and 1-neopentyl glycol, in a weight ratio of 4:1.

[0083] The above components are mixed evenly and added to a twin-screw extruder for reaction extrusion to obtain thermoplastic polyurethane elastomer. The extrusion temperature is 195℃, the screw speed is 200RPM, and the granulation process is cooled to 10℃.

[0084] Example 5

[0085] A high-resilience, low-melting-point thermoplastic polyurethane elastomer, the raw material composition by weight is as follows:

[0086] A) 80 parts of polyol: Polyethylene glycol butylene adipate (PEBA), number average molecular weight 4000 g / mol.

[0087] B) 16 parts of diisocyanate: 4,4-diphenylmethane diisocyanate.

[0088] C) Chain extender 4 parts: tert-butyldiamine derivative (R is cycloheptyl) 4,4-(cycloheptylmethylene)bis(2-tert-butyl)aniline and 1,4-butanediol, in a weight ratio of 5:1.

[0089] The above components are mixed evenly and added to a twin-screw extruder for reaction extrusion to obtain thermoplastic polyurethane elastomer. The extrusion temperature is 200℃, the screw speed is 200RPM, and the granulation process is cooled to 10℃.

[0090] Example 6

[0091] A high-resilience, low-melting-point thermoplastic polyurethane elastomer, its raw materials and weight composition are as follows:

[0092] A) 85 parts of polyol: 1,5-pentanediol adipate (PMA), number average molecular weight 3000 g / mol.

[0093] B) 13 parts of diisocyanate: 4,4-diphenylmethane diisocyanate.

[0094] C) Chain extender 2 parts: tert-butyldiamine derivative (R is cycloheptyl) 4,4-(cycloheptylmethylene)bis(2-tert-butyl)aniline and 1,4-butanediol, in a weight ratio of 6:1.

[0095] The above components are mixed evenly and added to a twin-screw extruder for reaction extrusion to obtain thermoplastic polyurethane elastomer. The extrusion temperature is 210℃, the screw speed is 210RPM, and the granulation process is cooled to 10℃.

[0096] Comparative Example 1

[0097] The preparation method is the same as in Example 1, except that 4,4-(cyclohexylmethylene)bis(2-tert-butyl)aniline (i.e., tert-butyldiamine derivative) is not added to the chain extender, while other operations and conditions remain unchanged.

[0098] Comparative Example 2

[0099] The preparation method is the same as in Example 1, except that the chain extender is replaced with an equal amount of hydroquinone dihydroxyethyl ether (HQEE), while other operations and conditions remain unchanged.

[0100] Comparative Example 3

[0101] The preparation method is the same as in Example 1, except that 4,4-(cyclohexylmethylene)bis(2-tert-butyl)aniline in the chain extender is replaced with an equal amount of hydroquinone dihydroxyethyl ether (HQEE), while other operations and conditions remain unchanged.

[0102] Comparative Example 4

[0103] The preparation method is the same as in Example 1, except that 4,4-(cyclohexylmethylene)bis(2-tert-butyl)aniline in the chain extender is replaced with an equal amount of 4,4-methylenebis(2,6-diisopropyl)aniline (M-DIPA), while other operations and conditions remain unchanged.

[0104] The melting point, resilience, and adhesion properties of the thermoplastic polyurethane elastomer samples prepared in the above embodiments and comparative examples were tested respectively, and the results are shown in Table 1.

[0105] Table 1. Performance test results of thermoplastic polyurethane elastomers in the examples and comparative examples.

[0106]

[0107] The thermoplastic polyurethane elastomer prepared according to the present invention has the characteristics of high resilience and low melting point, and also has excellent bonding properties.

Claims

1. A high-resilience, low-melting-point thermoplastic polyurethane elastomer, characterized in that, It is prepared from raw materials comprising the following parts by weight: 65-85 parts of polyols; 13-23 parts of diisocyanate; Chain extender 2-12 parts; The chain extender is a mixture of a tert-butyldiamine derivative and a diol, wherein the tert-butyldiamine derivative has the structure shown in Formula 1: In the formula, R is an alicyclic group of C5 to C7.

2. The high-resilience, low-melting-point thermoplastic polyurethane elastomer according to claim 1, characterized in that, R is cyclopentyl, cyclohexyl, or cycloheptyl.

3. The high-resilience, low-melting-point thermoplastic polyurethane elastomer according to claim 1, characterized in that, The tert-butyldiamine derivative is selected from one or more of 4,4-(cyclohexylmethylene)bis(2-tert-butyl)aniline, 4,4-(cyclopentylmethylene)bis(2-tert-butyl)aniline, and 4,4-(cycloheptylmethylene)bis(2-tert-butyl)aniline.

4. The high-resilience, low-melting-point thermoplastic polyurethane elastomer according to claim 1, characterized in that, The polyol has a number-average molecular weight of 1500-4000 g / mol; and / or The polyol has a hydroxyl value of 20-110 mgKOH / g and an acid value of 0-1 mgKOH / g.

5. The high-resilience, low-melting-point thermoplastic polyurethane elastomer according to claim 4, characterized in that, The polyol has a hydroxyl value of 25-80 mg KOH / g and an acid value of 0-0.5 mg KOH / g.

6. The high-resilience, low-melting-point thermoplastic polyurethane elastomer according to claim 1, characterized in that, The polyol is selected from any one or more of polyester polyols and polyether polyols.

7. The high-resilience, low-melting-point thermoplastic polyurethane elastomer according to claim 6, characterized in that, The polyester polyol is prepared by esterification of adipic acid and a diol; wherein the diol is selected from one or more of ethylene glycol, diethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, dipropylene glycol, and neopentyl glycol.

8. The high-resilience, low-melting-point thermoplastic polyurethane elastomer according to claim 7, characterized in that, The polyester polyol is one or more of poly(hexanediol adipate), poly(hexanediol adipate), and poly(ethylene glycol adipate).

9. The high-resilience, low-melting-point thermoplastic polyurethane elastomer according to claim 6, characterized in that, The polyester polyol is selected from one or more polycaprolactone polyols.

10. The high-resilience, low-melting-point thermoplastic polyurethane elastomer according to claim 9, characterized in that, The polycaprolactone polyol is prepared by ring-opening polymerization of ε-caprolactone initiated by a small molecule alcohol; wherein the small molecule alcohol is selected from one or more of 1,4-butanediol, 1,6-hexanediol, dipropylene glycol, and neopentyl glycol.

11. The high-resilience, low-melting-point thermoplastic polyurethane elastomer according to claim 10, characterized in that, The polycaprolactone polyol is a neopentyl glycol-based polycaprolactone polyol.

12. The high-resilience, low-melting-point thermoplastic polyurethane elastomer according to claim 6, characterized in that, The polyether polyol is prepared by ring-opening polymerization of an epoxy compound using a compound containing active hydrogen as an initiator; wherein the epoxy compound is selected from one or more of propylene oxide, tetrahydrofuran, and ethylene oxide; and the compound containing active hydrogen is selected from one or more of ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, and bisphenol A.

13. The high-resilience, low-melting-point thermoplastic polyurethane elastomer according to claim 12, characterized in that, The polyether polyol is polytetrahydrofuran ether diol.

14. The high-resilience, low-melting-point thermoplastic polyurethane elastomer according to claim 1, characterized in that, The diisocyanate component is selected from aromatic diisocyanates, aliphatic diisocyanates, or combinations thereof.

15. The high-resilience, low-melting-point thermoplastic polyurethane elastomer according to claim 14, characterized in that, The aromatic diisocyanate includes one or more of 4,4-diphenylmethane diisocyanate, toluene diisocyanate, and terephthalic diisocyanate.

16. The high-resilience, low-melting-point thermoplastic polyurethane elastomer according to claim 14, characterized in that, The aliphatic diisocyanate includes one or more of hexamethylene diisocyanate, 4,4-dicyclohexylmethane diisocyanate, isoflurone diisocyanate, and cyclohexanedimethylene diisocyanate.

17. The high-resilience, low-melting-point thermoplastic polyurethane elastomer according to claim 1, characterized in that, In the chain extender, the mass ratio of the tert-butyldiamine derivative to the diol is (1-9):1; and / or In the chain extender, the diol is selected from aliphatic diols.

18. The high-resilience, low-melting-point thermoplastic polyurethane elastomer according to claim 17, characterized in that, The mass ratio of the tert-butyldiamine derivative to the diol is (3-6):

1.

19. The high-resilience, low-melting-point thermoplastic polyurethane elastomer according to claim 17, characterized in that, The diol is selected from one or more of ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, dipropylene glycol, and neopentyl glycol.

20. A method for preparing the high-resilience, low-melting-point thermoplastic polyurethane elastomer according to any one of claims 1-19, characterized in that the step include: The polyol, diisocyanate, and chain extender are mixed evenly in a certain proportion, and then the mixture is reacted and granulated by a twin-screw extruder to obtain the high-resilience, low-melting-point thermoplastic polyurethane elastomer.

21. The preparation method according to claim 20, characterized in that, The extruder temperature is 120–220°C, and the screw speed is 180–220 RPM; and / or The granulation process is cooled to a temperature of 5–30°C.

22. The application of the high-resilience, low-melting-point thermoplastic polyurethane elastomer according to any one of claims 1-19 or the thermoplastic polyurethane elastomer prepared by the method of claim 20 or 21 in the field of clothing and footwear materials.

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