Thermoplastic polyurethane air pipe material as well as preparation method and application thereof

Abstract

The invention provides a thermoplastic polyurethane air pipe material as well as a preparation method and application thereof. The thermoplastic polyurethane gas pipe material is prepared by reaction of polyol, a chain extender with a specific structure and diisocyanate. The prepared pneumatic pipe has excellent strength, heat resistance and creep resistance.

Description

Technical Field

[0001] The invention relates to the technical field of thermoplastic polyurethane, and in particular to a thermoplastic polyurethane air pipe material with high strength and excellent heat resistance, and a preparation method and application thereof. Background Art

[0002] Thermoplastic polyurethane elastomer (TPU) is a polymer composed of flexible soft segments and rigid hard segments. It has rubber elasticity at low temperatures and can be plasticized and formed at elevated temperatures. TPU has excellent mechanical properties, high mechanical strength, wear resistance, and good toughness, and is widely used in the field of pipes.

[0003] Different types of pipes are improved in strength or weather resistance by compounding or covalent bonding. In order to solve the problem of PVC pipes becoming brittle at low temperatures, CN118290867A uses EVA and TPU compounding to significantly improve the impact strength, longitudinal shrinkage rate, and tensile strength. CN116948385A introduces a heat-resistant enhanced medical TPU mixture. The addition of polyamic acid to a thermoplastic polyurethane elastomer can improve the bending performance of the pipe and make the pipe have better heat resistance. However, both of these solutions improve the strength or heat resistance of the pipe by compounding with the help of the performance of the mixed material, and do not fundamentally improve the performance of polyurethane.

[0004] Therefore, it is necessary to develop a new method to improve the strength and heat resistance of polyurethane gas pipe materials in the field. Summary of the invention

[0005] In view of this, the object of the present invention is to provide a thermoplastic polyurethane air pipe material having excellent strength, heat resistance and creep resistance, which can be used to prepare extruded pipe products.

[0006] Another object of the present invention is to provide a method for preparing the thermoplastic polyurethane air pipe material, which has simple and easy operation steps.

[0007] To achieve the above purpose, the technical solution of the present invention is as follows:

[0008] The present invention provides a thermoplastic polyurethane air pipe material, which is prepared from raw materials comprising the following parts by weight:

[0009] (1) 30-80 parts, preferably 32-75 parts, more preferably 40-65 parts of a polyol;

[0010] (2) 20-50 parts, preferably 22-48 parts, more preferably 26-45 parts of diisocyanate;

[0011] (3) 3-17 parts, preferably 4-15 parts, more preferably 6-13 parts of a composition of a chain extender A and a chain extender B; wherein the chain extender A is selected from a small molecule diol; and the chain extender B has a structure as described in the following formula (1):

[0012]

[0013] Among them, R is selected from linear or branched C1-C10 alkyl, C3-C6 cycloalkyl, C6-C10 aryl, aralkyl, alkylaryl, polyether group, preferably C1 alkyl (such as methyl), C6 cycloalkyl (such as cyclohexyl), C6 aryl (such as phenyl).

[0014] In one embodiment, the chain extender A is selected from small molecule diols, preferably aliphatic alkylene glycols, which have the general formula HO-C n H 2n -OH, wherein n=a natural number of 1-10, such as 1, 3, 5, 7, 9, 10, etc., preferably n=4;

[0015] Preferably, the chain extender A is selected from one or more of butanediol and hexanediol.

[0016] The chain extender B is a product disclosed in the prior art, and there is no specific requirement for its source. It can be a commercially available product obtained through commercial channels, or it can be prepared based on existing methods, for example, with reference to the method disclosed in the document Journal of Natural Products (2017), 80 (1), 2-11.

[0017] Exemplarily, in the present invention, one of the chain extenders B having the structure described in formula (1) can be prepared according to the following method, and the specific steps are as follows:

[0018] Under N2 atmosphere, 3-amino-1,5-pentanediol and a compound having a hydroxyl group at one end and a carboxyl group at the other end are dissolved in an organic solvent (such as dichloromethane, dimethylformamide, etc.) at a molar ratio of 1:1-1.05, and reacted at room temperature for 4-6 hours under the action of a catalyst (such as EDC, HoBt, triethylamine, etc.). The liquid is separated and collected, and a white solid, i.e., the chain extender B, is obtained by conventional post-treatment such as concentration and purification;

[0019] The above method is carried out with reference to the process provided in the above document Journal of Natural Products (2017). Specifically, other relevant operations and process conditions in the above method of the present invention, and the devices used therein, can be carried out by using the corresponding conventional selections in the art. There is no particular limitation on this. Technicians can optimize the known processes in the prior art according to actual needs, and no further details will be given here.

[0020] In one embodiment, the molar ratio of chain extender A to chain extender B is 20-5:1, for example, 20:1, 18:1, 15:1, 13:1, 10:1, 8:1, 5:1, etc.

[0021] In one embodiment, the number average molecular weight of the polyol is 500-3000 g / mol, preferably 1000-2000 g / mol.

[0022] In one embodiment, the polyol is selected from one or more of polyester polyol, polyether polyol, polycaprolactone polyol and polycarbonate polyol.

[0023] In some specific examples, the number average molecular weight of the polyester polyol is between 500-3000, preferably between 1000-2000;

[0024] Preferably, the average hydroxyl functionality of the polyester polyol is 2;

[0025] Preferably, the polyester polyol is selected from one or two or more of poly(1,2-propylene adipate), poly(ethylene adipate), poly(diethylene adipate ether), poly(butylene adipate), poly(methylpropylene adipate), poly(1,2-propylene succinate), poly(ethylene succinate), poly(diethylene succinate), poly(dipropylene succinate), and poly(methylpropylene succinate).

[0026] In some specific examples, the number average molecular weight of the polyether polyol is between 500-000, preferably between 1000-2000;

[0027] Preferably, the average hydroxyl functionality of the polyether polyol is 2

[0028] Preferably, the polyether polyol is selected from one or two or more of polyoxypropylene glycol, polyoxypropylene and oxyethylene copolymer glycol, polytetramethylene glycol, and polybutadiene glycol.

[0029] In some specific examples, the number average molecular weight of the polycaprolactone polyol is 500-3000, preferably between 1000-2000;

[0030] Preferably, the average hydroxyl functionality of the polycaprolactone polyol is 2;

[0031] Preferably, the polycaprolactone polyol is selected from one or two or more of ethylene glycol-based polycaprolactone polyol, 1,4-butanediol-based polycaprolactone polyol, diethylene glycol-based polycaprolactone polyol, and neopentyl glycol-based polycaprolactone polyol.

[0032] In some specific examples, the number average molecular weight of the polycarbonate polyol is 500-3000, preferably between 1000-2000;

[0033] Preferably, the average hydroxyl functionality of the polycarbonate polyol is 2.

[0034] Preferably, the polycarbonate polyol can be synthesized by any one of the following methods: phosgene method, carbon dioxide regulated copolymerization method, cyclic carbonate ring-opening polymerization method or ester exchange method. Preferably, the polycarbonate polyol is synthesized by ester exchange reaction between diol and carbonate;

[0035] The above-mentioned synthesis methods are all existing processes in the field, and the present invention has no special requirements and will not be described in detail here.

[0036] In one embodiment, the diisocyanate is selected from one or more of aromatic diisocyanates, aliphatic diisocyanates, and alicyclic diisocyanates, preferably one or more of diphenylmethane diisocyanate and 4,4-dicyclohexylmethane diisocyanate.

[0037] The invention also provides a method for preparing the thermoplastic polyurethane air pipe material.

[0038] The thermoplastic polyurethane air pipe material can be prepared by a conventional co-extrusion method for thermoplastic polyurethane in the art, for example, by a one-step reaction using a twin-screw extruder.

[0039] Specifically, a method for preparing the thermoplastic polyurethane air pipe material comprises the following steps:

[0040] The polyol is mixed evenly with diisocyanate, chain extender A and chain extender B, and granulated by twin-screw reaction extrusion to prepare the thermoplastic polyurethane air pipe material.

[0041] Preferably, the extrusion temperature of the reactive extrusion is 80 to 240°C, preferably 120 to 220°C.

[0042] 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.

[0043] The thermoplastic polyurethane air pipe material of the present invention has excellent strength and heat resistance, creep resistance, a bursting pressure strength of up to 6.0 MPa or more, a heat resistance strength retention rate of up to 92%, and a creep resistance constant pressure dimensional change rate of up to 5.3%.

[0044] The thermoplastic polyurethane air pipe material described in the present invention can be used to prepare extruded pipe products, and is particularly suitable for preparing high-strength and heat-resistant extruded pipe products.

[0045] Compared with the prior art, the present invention has the following beneficial effects:

[0046] In the present invention, the chain extender B is bonded to the polyurethane main chain, and the amide bond in the chain extender can participate in the hydrogen bonding of the hard segment to promote the orientation of the hard segment. At the same time, the trihydroxy structure can form a cross-linking of the hard segment through a covalent bond, effectively promoting the improvement of strength and heat resistance, and also having creep resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 is the H-NMR spectrum of chain extender B1;

[0048] Figure 2 This is the H-NMR spectrum of chain extender B2. DETAILED DESCRIPTION

[0049] The present application is further described below in conjunction with embodiments, but the present application is not limited to the listed embodiments, but also includes equivalent improvements and modifications of the technical solutions defined in the claims attached to the present application.

[0050] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0051] Certain specific steps involved in the experimental methods used in the following examples are routine operations unless otherwise specified.

[0052] Unless otherwise specified, the materials and reagents used in the following examples can be obtained from commercial sources.

[0053] The main sources of raw materials used in the examples of the present invention are as follows:

[0054] BDO (1,4-butanediol), MDI (diphenylmethane diisocyanate), HMDI (4,4-dicyclohexylmethane diisocyanate), and PBA (polybutylene adipate) are all products sold by Wanhua Chemical Group Co., Ltd.

[0055] PTMG (polytetramethylene ether glycol) was purchased from BASF;

[0056] 3-Amino-1,5-pentanediol, 3-hydroxypropionic acid, and 3-hydroxymethylbenzoic acid were purchased from Aladdin;

[0057] Chain extender B was prepared according to the method disclosed in Journal of Natural Products (2017), 80(1), 2-11, and the specific steps are as follows:

[0058] Chain extender B1: 1 mol of 3-amino-1,5-pentanediol and 1 mol of 3-hydroxypropionic acid were dissolved in dimethylformamide, catalyzed by EDC, HoBt and triethylamine, and reacted in N2 atmosphere at room temperature for 4 hours. The liquid was separated and collected, and concentrated and purified to obtain a white solid, i.e., chain extender B1, with the following structural formula and attached H NMR spectrum. Figure 1 :

[0059]

[0060] Chain extender B2: 1 mol of 3-amino-1,5-pentanediol and 1 mol of 3-hydroxymethylbenzoic acid were dissolved in dimethylformamide, catalyzed by EDC, HoBt and triethylamine, and reacted in N2 atmosphere at room temperature for 4 hours. The liquid was separated and collected, and concentrated and purified to obtain a white solid, i.e., chain extender B2, with the following structural formula and NMR spectrum as attached. Figure 2 :

[0061]

[0062] Hereinafter, the thermoplastic polyurethane air pipe material provided by the present invention is introduced in detail through specific embodiments.

[0063] Embodiment 1:

[0064] Thermoplastic polyurethane air pipe material is prepared, and the raw material mass parts are as follows:

[0065] (1) 50.0 parts of PBA (polybutylene adipate, molecular weight 2000 g / mol),

[0066] (2) 38.3 parts of MDI (diphenylmethane diisocyanate),

[0067] (3) BDO (1,4-butanediol) and chain extender B1 total 12.5 parts, the molar ratio of the two is 5:1.

[0068] The above raw materials are mixed evenly, extruded by twin-screw reaction (extruder temperature is 120-210°C, die head temperature is 220°C), and then pelletized underwater to obtain thermoplastic polyurethane air pipe material.

[0069] Embodiment 2:

[0070] Thermoplastic polyurethane air pipe material is prepared, and the raw material mass parts are as follows:

[0071] (1) 50.0 parts of PTMG (polytetramethylene ether glycol, molecular weight 1000 g / mol),

[0072] (2) 40.0 parts of MDI (diphenylmethane diisocyanate),

[0073] (3) BDO (1,4-butanediol) and chain extender B1 total 10.2 parts, the molar ratio of the two is 20:1.

[0074] Thermoplastic polyurethane air pipe material was prepared in the same manner as in Example 1.

[0075] Embodiment 3:

[0076] Thermoplastic polyurethane air pipe material is prepared, and the raw material mass parts are as follows:

[0077] (1) 60.0 parts of PBA (polybutylene adipate, molecular weight 2000 g / mol),

[0078] (2) 29.5 parts of MDI (diphenylmethane diisocyanate),

[0079] (3) HDO (1,6-hexanediol) and chain extender B2 total 10.9 parts, the molar ratio of the two is 10:1.

[0080] Thermoplastic polyurethane air pipe material was prepared in the same manner as in Example 1.

[0081] Embodiment 4:

[0082] Thermoplastic polyurethane air pipe material is prepared, and the raw material mass parts are as follows:

[0083] (1) 60.0 parts of PTMG (polytetramethylene ether glycol, molecular weight 2000 g / mol),

[0084] (2) 33.7 parts of HMDI (4,4-dicyclohexylmethane diisocyanate),

[0085] (3) BDO (1,4-butanediol) and chain extender B2 total 7.19 parts, the molar ratio of the two is 5:1.

[0086] Thermoplastic polyurethane air pipe material was prepared in the same manner as in Example 1.

[0087] Embodiment 5:

[0088] Thermoplastic polyurethane air pipe material is prepared, and the raw material mass parts are as follows:

[0089] (1) 65.0 parts of PBA (polybutylene adipate, molecular weight 2000 g / mol),

[0090] (2) 28.2 parts of HMDI (4,4-dicyclohexylmethane diisocyanate),

[0091] (3) BDO (1,4-butanediol) and chain extender B2 total 7.1 parts, the molar ratio of the two is 20:1.

[0092] Thermoplastic polyurethane air pipe material was prepared in the same manner as in Example 1.

[0093] Embodiment 6:

[0094] Thermoplastic polyurethane air pipe material is prepared, and the raw material mass parts are as follows:

[0095] (1) 65.0 parts of PTMG (polytetramethylene ether glycol, molecular weight 2000 g / mol),

[0096] (2) 29.4 parts of HMDI (4,4-dicyclohexylmethane diisocyanate),

[0097] (3) HDO (1,6-hexanediol) and chain extender B1 total 5.7 parts, the molar ratio of the two is 10:1.

[0098] Thermoplastic polyurethane air pipe material was prepared in the same manner as in Example 1.

[0099] Comparative Example 1:

[0100] Thermoplastic polyurethane air pipe material is prepared, and the raw material mass parts are as follows:

[0101] (1) 60.0 parts of PBA (polybutylene adipate, molecular weight 2000 g / mol),

[0102] (2) 31.5 parts of MDI (diphenylmethane diisocyanate),

[0103] (3) 8.5 parts of BDO (1,4-butanediol).

[0104] Thermoplastic polyurethane air pipe material was prepared in the same manner as in Example 1.

[0105] Comparative Example 2:

[0106] Thermoplastic polyurethane air pipe material is prepared, and the raw material mass parts are as follows:

[0107] (1) 65.0 parts of PTMG (polytetramethylene ether glycol, molecular weight 1000 g / mol),

[0108] (2) 28.2 parts of HMDI (4,4-dicyclohexylmethane diisocyanate),

[0109] (3) BDO (1,4-butanediol) 6.8 parts.

[0110] Thermoplastic polyurethane air pipe material was prepared in the same manner as in Example 1.

[0111] Comparative Example 3:

[0112] Thermoplastic polyurethane air pipe material is prepared, and the raw material mass parts are as follows:

[0113] (1) 65.0 parts of PTMG (polytetramethylene ether glycol, molecular weight 2000 g / mol),

[0114] (2) 29.6 parts of HMDI (4,4-dicyclohexylmethane diisocyanate),

[0115] (3) HDO (1,6-hexanediol) and trimethylolethane are 5.5 parts in total, and the molar ratio between the two is 10:1.

[0116] Thermoplastic polyurethane air pipe material was prepared in the same manner as in Example 1.

[0117] The thermoplastic polyurethane air pipe materials prepared in Examples 1-6 and Comparative Examples 1-3 were extruded to prepare pipe samples, and performance tests were performed respectively using the following methods. The results are shown in Table 1.

[0118] Burst pressure test: On a burst pressure test machine, use three 30cm long pipes to test the burst pressure under the conditions of water flow, 23°C, and a pressurization rate of 0.07Mpa / s, and take the average value.

[0119] Heat resistance test: Three specimens were placed at 113°C for 8 weeks to test the tensile strength retention of the samples before and after placement. Hardness was tested according to ASTM D2240, and tensile strength was tested using ASTM D412.

[0120] Creep expansion rate test: Use three 30cm long pipes on a pipe static pressure tester to test the outer diameter. After 72 hours at 60℃ and 0.9Mpa, test the outer diameter again. Calculate the expansion rate of the outer diameter.

[0121] Table 1 Performance test results of thermoplastic polyurethane air pipe materials in embodiments and comparative examples

[0122]

[0123] It can be seen from Table 1 that the thermoplastic polyurethane pipe of the present invention has excellent comprehensive performance. It not only has higher strength, but also Examples 1-6 can obtain higher burst pressure and higher heat resistance strength retention rate, and creep expansion resistance is also improved.

[0124] Obviously, the above embodiments of the present invention are merely examples for clearly explaining the present invention, and are not intended to limit the implementation methods of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is impossible to list all implementation methods here. All obvious changes or modifications derived from the technical solution of the present invention are within the spirit scope of the present invention.

Claims

1. A thermoplastic polyurethane air pipe material, characterized in that: Prepared from the following raw materials in parts by weight: (1) 30-80 parts, preferably 32-75 parts, more preferably 40-65 parts of a polyol; (2) 20-50 parts, preferably 22-48 parts, more preferably 26-45 parts of diisocyanate; (3) 3-17 parts, preferably 4-15 parts, more preferably 6-13 parts of a composition of a chain extender A and a chain extender B; wherein the chain extender A is selected from a small molecule diol; and the chain extender B has a structure as described in the following formula (1): Wherein, R is selected from linear or branched C1-C10 alkyl, C3-C6 cycloalkyl, C6-C10 aryl, aralkyl, alkylaryl, polyether group, preferably C1 alkyl, C6 cycloalkyl, C6 aryl.

2. The thermoplastic polyurethane air pipe material according to claim 1, characterized in that: The chain extender A is selected from small molecule diols, preferably aliphatic alkylene glycols, which have the general formula HO-C n H 2n -OH, wherein n=a natural number of 1-10, preferably n=4; Preferably, the chain extender A is selected from one or more of butanediol and hexanediol.

3. The thermoplastic polyurethane air pipe material according to claim 1, characterized in that: The molar ratio of the chain extender A to the chain extender B is 20-5:

1.

4. The thermoplastic polyurethane air pipe material according to claim 1, characterized in that: The number average molecular weight of the polyol is 500-3000 g / mol, preferably 1000-2000 g / mol.

5. The thermoplastic polyurethane air pipe material according to claim 1 or 4, characterized in that: The polyol is selected from one or more of polyester polyol, polyether polyol, polycaprolactone polyol and polycarbonate polyol.

6. The thermoplastic polyurethane air pipe material according to claim 5, characterized in that: The number average molecular weight of the polyester polyol is between 500-3000, preferably between 1000-2000; Preferably, the average hydroxyl functionality of the polyester polyol is 2; Preferably, the polyester polyol is selected from one or two or more of polypropylene adipate diol, polyethylene adipate diol, polyethylene adipate diol, polymethylpropylene adipate diol, polypropylene succinate-1,2-glycol ester diol, polyethylene succinate diol, polydiethylene succinate diol, polydipropylene succinate diol, and polymethylpropylene succinate diol; and / or The number average molecular weight of the polyether polyol is between 500 and 3000, preferably between 1000 and 2000; Preferably, the average hydroxyl functionality of the polyether polyol is 2 Preferably, the polyether polyol is selected from one or two or more of polyoxypropylene glycol, polyoxypropylene and oxyethylene copolymer glycol, polytetramethylene glycol, and polybutadiene glycol; and / or The number average molecular weight of the polycaprolactone polyol is 500-3000, preferably between 1000-2000; Preferably, the average hydroxyl functionality of the polycaprolactone polyol is 2; Preferably, the polycaprolactone polyol is selected from one or two or more of ethylene glycol polycaprolactone polyol, 1,4-butanediol polycaprolactone polyol, diethylene glycol polycaprolactone polyol, and neopentyl glycol polycaprolactone polyol; and / or The number average molecular weight of the polycarbonate polyol is 500-3000, preferably between 1000-2000; Preferably, the average hydroxyl functionality of the polycarbonate polyol is 2; Preferably, the polycarbonate polyol is synthesized by any one of the following methods: phosgene method, carbon dioxide regulated copolymerization method, cyclic carbonate ring-opening polymerization method or ester exchange method. Preferably, the polycarbonate polyol is synthesized by ester exchange reaction between diol and carbonate.

7. The thermoplastic polyurethane air pipe material according to claim 5, characterized in that: The diisocyanate is selected from one or more of aromatic diisocyanate, aliphatic diisocyanate and alicyclic diisocyanate, preferably one or more of diphenylmethane diisocyanate and 4,4-dicyclohexylmethane diisocyanate.

8. A method for preparing the thermoplastic polyurethane air pipe material according to any one of claims 1 to 7, characterized in that: The steps are: The polyol is mixed evenly with diisocyanate, chain extender A and chain extender B, and granulated by twin-screw reaction extrusion to prepare the thermoplastic polyurethane air pipe material.

9. The preparation method according to claim 8, characterized in that: The extrusion temperature of the reactive extrusion is 80-240°C, preferably 120-220°C.

10. The thermoplastic polyurethane air pipe material according to any one of claims 1 to 7 or the thermoplastic polyurethane air pipe material prepared by the method according to claim 8 or 9 is used to prepare extruded pipe products, especially suitable for preparing high-strength and heat-resistant extruded pipe products.

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