High-resilience low-melting-point thermoplastic polyurethane elastomer as well as preparation method and application thereof

Abstract

The invention belongs to the field of polyurethane elastomers, and particularly relates to a high-resilience low-melting-point thermoplastic polyurethane elastomer and a preparation method and application thereof. The high-resilience low-melting-point thermoplastic polyurethane elastomer is prepared from the following raw materials in parts by weight: 65-85 parts of polyol; 13 to 23 parts of diisocyanate; 2-12 parts of a chain extender; wherein the chain extender is a mixture of a tert-butyl diamine derivative and dihydric alcohol. According to the invention, the tert-butyl diamine derivative is introduced into the chain extender component, and under the synergistic effect of specific components, a twin-screw extruder is adopted for one-step reaction to prepare the chain extender. The 300% rebound retention rate of the thermoplastic polyurethane elastomer can reach 95% or above, the melting point is 85-120 DEG C, and meanwhile, the thermoplastic polyurethane elastomer has excellent adhesive property.

Description

Technical Field

[0001] The invention belongs to the field of polyurethane and relates to a thermoplastic polyurethane elastomer and a preparation method and application thereof. Background Art

[0002] Thermoplastic polyurethane elastomer (TPU) is a block copolymer composed of polyol soft segment, isocyanate and chain extender hard segment, and its performance is between rubber and plastic. Therefore, through the special structural composition, it can obtain elasticity like rubber and rigidity like plastic. The field of footwear and clothing has always been one of the main application areas of TPU products. With the improvement of people's living standards, the footwear and clothing industry has an increasing demand for high resilience, low processing temperature and high bonding strength of materials. The current mainstream high-resilience thermoplastic polyurethane products in the industry have a very high melting point (above 140°C), so a higher processing temperature is required to achieve better bonding with the substrate.

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

[0004] In view of the above problems existing in the prior art, the purpose of the present invention is to provide a high-resilience low-melting-point thermoplastic polyurethane elastomer to solve the problem that traditional high-resilience thermoplastic polyurethane elastomers are difficult to achieve high elasticity, low melting point and high adhesion properties.

[0005] To solve the above problems, the present invention adopts the following technical solutions:

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

[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 to 23 parts of diisocyanate, for example, 13 parts, 15 parts, 18 parts, 20 parts, 22 parts, 23 parts, etc.;

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

[0010] Wherein, the chain extender is a mixture of tert-butyldiamine derivatives and diols.

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

[0012]

[0013] In the formula, R is a C5-C7 alicyclic group, preferably a cyclopentyl group, a cyclohexyl group, or a cycloheptyl group.

[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 a 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] Further, 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, the polyol has a hydroxyl value of 25-80 mgKOH / g and an acid value of 0-0.5 mgKOH / g;

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

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

[0019] More preferably, the polyester polyol is one or more of poly(hexanediol butanediol adipate), poly(hexanediol adipate), and poly(ethylene glycol butanediol adipate);

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

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

[0022] Preferably, the polycaprolactone polyol is prepared by a method known in the industry, using a small molecule alcohol as an initiator to initiate the ring-opening polymerization of ε-caprolactone; wherein the small molecule alcohol can 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-started polycaprolactone polyol.

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

[0025] Further, the aromatic diisocyanate includes one or more of 4,4-diphenylmethane diisocyanate, toluene diisocyanate, and p-phenylene diisocyanate, preferably 4,4-diphenylmethane diisocyanate;

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

[0027] In a specific embodiment, in the chain extender, the mass ratio of the tert-butyl diamine derivative to the diol is (1-9):1, such as 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-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,6-hexanediol, dipropylene glycol, and neopentyl glycol, and more preferably 1,4-butanediol.

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

[0030] The high resilience low melting point thermoplastic polyurethane elastomer can be prepared by the co-mixing extrusion method conventionally used in the field of thermoplastic polyurethane elastomer, for example, by a one-step reaction using a twin-screw extruder.

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

[0032] The polyol, diisocyanate and chain extender are mixed uniformly in proportion, and then granulated by twin-screw reaction extrusion to obtain the high-resilience and low-melting-point thermoplastic polyurethane elastomer;

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

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

[0035] For the related operations and process conditions not involved in the preparation method of the present invention, and the devices used therein, corresponding conventional selections in the art can be adopted. The technicians can optimize them according to actual needs based on the known processes in the prior art, and there is no particular limitation on this.

[0036] The thermoplastic polyurethane elastomer of the present invention has a 300% rebound retention rate of more than 95%, a melting point of 85-120° C., and excellent bonding performance, and is suitable for the fields of clothing, shoes, etc.

[0037] The characteristics and effective results of the present invention are:

[0038] The thermoplastic polyurethane elastomer of the present invention adopts a tert-butyl diamine derivative and a diol as a chain extender component, wherein the aromatic diamine group can form a strong urea bond with the isocyanate group, thereby obtaining high resilience. At the same time, the tert-butyl side chain structure is compounded with the diol, which weakens the crystallization performance of the elastomer to a certain extent. The components cooperate to obtain a low melting point, high resilience thermoplastic polyurethane elastomer, which also has excellent bonding performance and is particularly suitable for the field of footwear and clothing. DETAILED DESCRIPTION

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

[0040] In the embodiments and comparative examples of the present invention, the main raw materials used are from the following sources. Unless otherwise specified, other raw materials and reagents were purchased from commercial sources:

[0041] Polyester polyol (Wanhua Chemical):

[0042] Polybutylene adipate (PBHA, number average molecular weight 2000, hydroxyl value 56 mgKOH / g, acid value 0.2 mgKOH / g),

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

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

[0045] Polypentanediol adipate (PMA, number average molecular weight 3000), hydroxyl value 37.5 mgKOH / g, acid value 0.1 mgKOH / g,

[0046] Polybutylene glycol adipate (PBHA, number average molecular weight 1500, hydroxyl value 75 mgKOH / g, acid value 0.2 mgKOH / 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 polyol (BASF): polytetramethylene ether diol (PTMEG, number average molecular weight 2000, hydroxyl value 56 mgKOH / g, acid value 0.15 mgKOH / g);

[0049] Polycaprolactone diol (Hunan Juren): polycaprolactone diol (PCL, initiator NPG, number average molecular weight 2000, hydroxyl value 56 mgKOH / g, acid value 0.1 mgKOH / 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 materials of which are composed by weight as follows:

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

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

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

[0065] The above components were mixed evenly, added into a twin-screw extruder, and reactively extruded to obtain a thermoplastic polyurethane elastomer. The extrusion temperature was 200° C., the screw speed was 200 RPM, and the pelletizing process was cooled to a temperature of 10° C.

[0066] Example 2

[0067] A high-resilience low-melting-point thermoplastic polyurethane elastomer, the raw materials of which are composed by weight as follows:

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

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

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

[0071] The above components were mixed evenly, added into a twin-screw extruder, and reactively extruded to obtain a thermoplastic polyurethane elastomer. The extrusion temperature was 220° C., the screw speed was 210 RPM, and the pelletizing process was cooled to a temperature of 10° C.

[0072] Example 3

[0073] A high-resilience low-melting-point thermoplastic polyurethane elastomer, the raw materials of which are composed by weight as follows:

[0074] A) Polyol 70 parts: polytetramethylene ether glycol (PTMEG), number average molecular weight 2000 g / mol.

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

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

[0077] The above components were mixed evenly, added into a twin-screw extruder, and reactively extruded to obtain a thermoplastic polyurethane elastomer. The extrusion temperature was 190° C., the screw speed was 200 RPM, and the pelletizing process was cooled to a temperature of 10° C.

[0078] Example 4

[0079] A high-resilience low-melting-point thermoplastic polyurethane elastomer, the raw materials of which are composed by weight as follows:

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

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

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

[0083] The above components were mixed evenly, added into a twin-screw extruder, and reactively extruded to obtain a thermoplastic polyurethane elastomer. The extrusion temperature was 195° C., the screw speed was 200 RPM, and the pelletizing process was cooled to a temperature of 10° C.

[0084] Example 5

[0085] A high-resilience low-melting-point thermoplastic polyurethane elastomer, the raw materials of which are composed by weight as follows:

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

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

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

[0089] The above components were mixed evenly, added into a twin-screw extruder, and reactively extruded to obtain a thermoplastic polyurethane elastomer. The extrusion temperature was 200° C., the screw speed was 200 RPM, and the pelletizing process was cooled to a temperature of 10° C.

[0090] Example 6

[0091] A high-resilience low-melting-point thermoplastic polyurethane elastomer, the raw materials and weight parts of which are as follows:

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

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

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

[0095] The above components were mixed evenly, added into a twin-screw extruder, and reactively extruded to obtain a thermoplastic polyurethane elastomer. The extrusion temperature was 210° C., the screw speed was 210 RPM, and the pelletizing process was cooled to a temperature of 10° C.

[0096] Comparative Example 1

[0097] The preparation method was prepared with reference to Example 1, except that 4,4-(cyclohexylmethylene)bis(2-tert-butyl)aniline (ie, a tert-butyldiamine derivative) was not added to the chain extender, and other operations and conditions remained unchanged.

[0098] Comparative Example 2

[0099] The preparation method was prepared in accordance with Example 1, except that the chain extender was replaced by an equal amount of hydroquinone dihydroxyethyl ether (HQEE), and other operations and conditions remained unchanged.

[0100] Comparative Example 3

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

[0102] Comparative Example 4

[0103] The preparation method was prepared by referring to Example 1, except that the 4,4-(cyclohexylmethylene)bis(2-tert-butyl)aniline in the chain extender was replaced by an equal amount of 4,4-methylenebis(2,6-diisopropyl)aniline (M-DIPA), and other operations and conditions remained unchanged.

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

[0105] Table 1 Test results of thermoplastic polyurethane elastomer performance of 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 performance.

Claims

1. A high resilience low melting point thermoplastic polyurethane elastomer, characterized in that: It is prepared from the following raw materials in parts by weight: 65-85 parts of polyol; 13-23 parts of diisocyanate; Chain extender 2-12 parts; Wherein, the chain extender is a mixture of tert-butyldiamine derivatives and diols.

2. The high resilience low melting point thermoplastic polyurethane elastomer according to claim 1, characterized in that: The tert-butyl diamine derivative has a structure as shown in Formula 1: In the formula, R is a C5-C7 alicyclic group, preferably a cyclopentyl group, a cyclohexyl group, or a cycloheptyl group; 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.

3. 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. Preferably, the polyol has a hydroxyl value of 25-80 mgKOH / g and an acid value of 0-0.5 mgKOH / g.

4. The high resilience low melting point thermoplastic polyurethane elastomer according to any one of claims 1 to 3, characterized in that: The polyol may be a combination of any one or more of polyester polyol, polyether polyol and polycaprolactone polyol; Preferably, the polyester polyol is prepared by esterification of adipic acid and diol; wherein the diol is selected from one or more of ethylene glycol, diethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,6-hexanediol, diethylene glycol, dipropylene glycol, and neopentyl glycol; More preferably, the polyester polyol is one or more of poly(hexanediol butanediol adipate), poly(hexanediol adipate), and poly(ethylene glycol butanediol adipate); Preferably, the polyether polyol is prepared by ring-opening polymerization of an epoxidized compound using an active hydrogen-containing compound as an initiator; wherein the epoxide compound is selected from one or more of propylene oxide, tetrahydrofuran, and ethylene oxide; and the active hydrogen-containing compound is selected from one or more of ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, and bisphenol A. More preferably, the polyether polyol is polytetramethylene ether diol; Preferably, the polycaprolactone polyol is prepared by using a small molecule alcohol as an initiator to initiate the ring-opening polymerization of ε-caprolactone; wherein the small molecule alcohol is selected from one or more of 1,4-butanediol, 1,6-hexanediol, dipropylene glycol, and neopentyl glycol; More preferably, the polycaprolactone polyol is a neopentyl glycol-started polycaprolactone polyol.

5. 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 a combination thereof; Preferably, the aromatic diisocyanate includes one or more of 4,4-diphenylmethane diisocyanate, toluene diisocyanate, and p-phenylene diisocyanate, preferably 4,4-diphenylmethane diisocyanate; Preferably, the aliphatic diisocyanate includes one or more of hexamethylene diisocyanate, 4,4-dicyclohexylmethane diisocyanate, isophorone diisocyanate, and cyclohexane dimethylene diisocyanate, preferably hexamethylene diisocyanate.

6. 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-butyl diamine derivative to the diol is (1-9):1, preferably (3-6):1; and or In the chain extender, the diol is selected from aliphatic diols, preferably one or more of ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,6-hexanediol, dipropylene glycol, and neopentyl glycol, and more preferably 1,4-butanediol.

7. A method for preparing the high resilience low melting point thermoplastic polyurethane elastomer according to any one of claims 1 to 6, characterized in that the steps include: The polyol, diisocyanate and chain extender are uniformly mixed in proportion, and then granulated by twin-screw reaction extrusion to obtain the high-resilience and low-melting-point thermoplastic polyurethane elastomer.

8. The preparation method according to claim 7, characterized in that: The extruder temperature is 120-220°C and the screw speed is 180-220RPM; and or The granulation process is cooled to a temperature of 5 to 30°C.

9. Use of the high resilience and low melting point thermoplastic polyurethane elastomer according to any one of claims 1 to 6 or the thermoplastic polyurethane elastomer prepared by the method according to claim 7 or 8 in the field of clothing and footwear.

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