Hand sweat-resistant thermoplastic polyurethane elastomer

Abstract

The invention provides a hand sweat resistant thermoplastic polyurethane elastomer. The elastomer is prepared from the following raw materials: polyol, diisocyanate, a chain extender and a special hand perspiration-resistant auxiliary agent. According to the elastomer, the resistance to hand sweat is improved, and the service life of the hand-sweat-resistant thermoplastic polyurethane elastomer is effectively prolonged.

Description

Technical Field

[0001] The present invention belongs to the field of polyurethanes, and particularly relates to a sweat-resistant thermoplastic polyurethane elastomer. Background Art

[0002] Thermoplastic polyurethane elastomer (TPU) is a block polymer composed of hard segments formed by the reaction of chain extenders and diisocyanates and soft segments formed by polyols. Due to the characteristics of its molecular structure, it has rubber elasticity at low temperatures and can be plasticized and molded after the temperature is raised. It is a material that can be processed and formed for the second time, and has the advantages of high mechanical strength, wear resistance, good toughness, good processing performance, and wide application.

[0003] Thermoplastic polyurethane elastomers can be used in the production of products such as smart wearables, mobile phone sheaths, and overmolding. However, in actual use, due to long-term contact with sweat, they are prone to yellowing due to the infiltration of sweat, affecting the use experience.

[0004] CN202111611373.9 discloses a sweat-resistant TPU composite material and its preparation method, including 50-99 parts by weight of thermoplastic polyurethane elastomer and 1-50 parts by weight of self-healing thermosetting polyurethane. The thermoplastic polyurethane composite material of this invention has excellent characteristics such as resistance to marker pens, oil stains, and cosmetics, and the product can be applied to smart wearables such as watches and bracelets; this method has good resistance to oil stains and cosmetics, but the resistance effect to long-term infiltration of sweat is not ideal.

[0005] In summary, the TPU materials currently used for smart wearables and mobile phone sheaths that are in long-term contact with the hand still have the problem of yellowing of the products caused by resistance to sweat infiltration that needs to be solved urgently. Summary of the Invention

[0006] In order to solve the above technical problems, one of the purposes of the present invention is to provide a sweat-resistant thermoplastic polyurethane elastomer, which improves its resistance to sweat and effectively improves the service life of the sweat-resistant thermoplastic polyurethane elastomer.

[0007] To achieve the above purpose, the technical solutions adopted by the present invention are as follows:

[0008] A sweat-resistant thermoplastic polyurethane elastomer, wherein the elastomer is prepared from raw materials comprising the following mass ratios:

[0009] Polyol, 40-70 parts, preferably 45-65 parts,

[0010] Diisocyanate, 20-45 parts, preferably 25-50 parts,

[0011] Chain extender, 5-15 parts, preferably 6-10 parts,

[0012] Anti-sweating agent B1, 0.5 - 8 parts, preferably 2 - 5 parts,

[0013] Anti-sweating agent B2, 0.5 - 8 parts, preferably 2 - 5 parts,

[0014] Among them, the structural formula of the anti-sweating agent B1 is:

[0015]

[0016] In the formula, x and y respectively represent natural numbers between 0 and 4, and n represents a natural number between 4 and 15, preferably a natural number between 5 and 8;

[0017] Among them, the structural formula of the anti-sweating agent B2 is:

[0018]

[0019] In the formula, p and q respectively represent natural numbers between 0 and 4, and m represents a natural number between 10 and 25, preferably a natural number between 12 and 20.

[0020] In the present invention, the two kinds of additives can form hydrogen bond structures with each other or with TPU. The dense hydrogen bond structure is beneficial to hindering the invasion of hand sweat; meanwhile, the fluorine-containing molecular chain segments provide a lower surface energy to further hinder the invasion of hand sweat; and, the special molecular repeating units can be designed according to the structure of the base material, making the molecular structure of the additive more conducive to the hydrogen bond combination with TPU and more conducive to introducing fluorine-containing chain segments.

[0021] In one embodiment of the present invention, the polyol is one or a combination of polyester polyol, polyether polyol, polycaprolactone polyol, polycarbonate polyol; preferably, the number average molecular weight of the polyol is 500 - 6000 g / mol, preferably 1000 - 3000 g / mol.

[0022] In one embodiment of the present invention, the diisocyanate is one or more of aromatic diisocyanates, aliphatic diisocyanates, and alicyclic diisocyanates, preferably one or more of 4,4'-diphenylmethane diisocyanate, 2,4-diphenylmethane diisocyanate, 2,2'-diphenylmethane diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 1,5-naphthalene diisocyanate, 1,4-phenylene diisocyanate, m-xylylene diisocyanate, diphenylmethane-3,3'-dimethoxy-4,4'-diisocyanate, 1,6-hexamethylene diisocyanate, 1,10-decane diisocyanate, 1,3-cyclohexane diisocyanate, 1,4-cyclohexane diisocyanate, 2,4-hexahydrotoluene diisocyanate, 2,6-hexahydrotoluene diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, 2,2'-dicyclohexylmethane diisocyanate, 2,4-dicyclohexylmethane diisocyanate, isophorone diisocyanate, more preferably one or more of 4,4'-diphenylmethane diisocyanate, 1,6-hexamethylene diisocyanate, 2,4-toluene diisocyanate, 4,4'-dicyclohexylmethane diisocyanate.

[0023] In one embodiment of the present invention, the chain extender is an aliphatic and / or alicyclic diol having 2 to 6 carbon atoms, preferably one or more of ethylene glycol, 1,3-propanediol, 1,2-propanediol, diethylene glycol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, more preferably 1,4-butanediol and / or 1,4-cyclohexanedimethanol.

[0024] Another object of the present invention is to provide a method for preparing a sweat-resistant thermoplastic polyurethane elastomer.

[0025] A method for preparing a sweat-resistant thermoplastic polyurethane elastomer, wherein the polyurethane elastomer is the above-mentioned elastomer, and the method is: reacting a polyol with a diisocyanate to obtain a prepolymer, adding a chain extender for chain extension and a sweat-resistant additive, and reacting and extruding and granulating through an extruder to obtain an elastomer product.

[0026] Another object of the present invention is to provide a use of a sweat-resistant thermoplastic polyurethane elastomer.

[0027] A use of a sweat-resistant thermoplastic polyurethane elastomer, wherein the polyurethane elastomer is the above-mentioned elastomer or the elastomer prepared by the above method, and the polyurethane elastomer is used for preparing polyurethane injection molded products, preferably used for polyurethane injection molded products in contact with the human body, more preferably used for preparing mobile phone sheaths, smart wearables, and overmolded products.

[0028] Compared with the prior art, the positive effects of the present invention are:

[0029] (1) After introducing the sweat-resistant auxiliary agent, the TPU still maintains good strength and toughness, making it suitable for injection molding.

[0030] (2) After introducing the sweat-resistant auxiliary agent, products such as smart wearables and mobile phone cases can remain non-yellowing within 3 - 5 days, greatly improving the user experience of consumers. Specific implementation mode

[0031] Main raw material information in the examples:

[0032] Methyl isothiocyanate was purchased from TCI Chemical Industry Development Co., Ltd.

[0033] Amino-terminated perfluoropolyether was purchased from Solvay Chemicals Co., Ltd.

[0034] PBA2000 (molecular weight 2000), PBA6000 (molecular weight 6000) were purchased from Wanhua Chemical Group Co., Ltd.

[0035] PEA1000 (molecular weight 1000) was purchased from Wanhua Chemical Group Co., Ltd.

[0036] PEA4000 (molecular weight 4000) was purchased from Wanhua Chemical Group Co., Ltd.

[0037] PTMG800 (molecular weight 800) was purchased from BASF SE

[0038] PCL2000 (molecular weight 2000) was purchased from Juren Chemical New Materials

[0039] Butanediol was purchased from Wanhua Chemical Group Co., Ltd.

[0040] Ethylene glycol: Purchased from Wanhua Chemical Group Co., Ltd.

[0041] MDI-100F was purchased from Wanhua Chemical Group Co., Ltd.

[0042] HDI was purchased from Wanhua Chemical Group Co., Ltd.

[0043]

[0044] Temperature settings (°C) for each zone of the extruder, extruder speed (rpm):

[0045]

[0046]

[0047] In the examples and comparative examples, 1 part is equivalent to 1 Kg.

[0048] Example 1

[0049] 60 parts of PBA2000 polyol and 30 parts of MDI are respectively metered by metering pumps and then enter a mixer, react at 120 °C for 4 h, and then enter a tubular reactor through a booster pump to prepare prepolymer D1.

[0050] Prepolymer D1 enters the starting feeding port of the first zone of a twin-screw extruder. 10 parts of BDO are metered by a metering pump and enter the reaction zone 2 of the twin-screw extruder. 3 parts of sweat-resistant additive B1 and 4 parts of B2 are metered by metering pumps and heated to 80 °C through a temperature controller, and then enter the reaction zone 5 of the twin-screw extruder, and then are extruded and granulated by the extruder reaction to form product particles.

[0051] Among them, B1 has the following structure, x = 3, y = 2, n = 10

[0052]

[0053] B2 has the following structure, p = 4, q = 1, m = 15

[0054]

[0055] Example 2

[0056] A method for preparing a sweat-resistant thermoplastic polyurethane elastomer includes the following steps:

[0057] 65 parts of PCL2000 polyol and 23 parts of HDI are respectively metered by metering pumps and then enter a mixer, react at 120 °C for 4 h, and then enter a tubular reactor through a booster pump to prepare prepolymer D2.

[0058] Prepolymer D2 enters the starting feeding port of the first zone of a twin-screw extruder. 10 parts of BDO are metered by a metering pump and enter the reaction zone 2 of the twin-screw extruder. 2 parts of sweat-resistant additive B1 and 8 parts of B2 are metered by metering pumps and heated to 80 °C through a temperature controller, and then enter the reaction zone 4 of the twin-screw extruder, and then are extruded and granulated by the extruder reaction to form product particles.

[0059] Among them, B1 has the following structure, x = 3, y = 2, n = 10

[0060]

[0061] B2 has the following structure, p = 4, q = 1, m = 15

[0062]

[0063] Example 3

[0064] A method for preparing a sweat-resistant thermoplastic polyurethane elastomer includes the following steps:

[0065] 45 parts of gPBA6000 polyol and 48 parts of MDI are respectively metered by metering pumps and then enter a mixer, react at 120 °C for 4 h, and then enter a tubular reactor through a booster pump to prepare prepolymer D3.

[0066] Prepolymer D3 enters the starting feeding port of the first zone of a twin-screw extruder. 7 parts of ethylene glycol are metered by a metering pump and enter the second reaction zone of the twin-screw extruder. 8 parts of sweat-resistant additive B1 and 5 parts of B2 are metered by metering pumps and heated to 80 °C through a temperature controller, and then enter the sixth reaction zone of the twin-screw extruder, and then are extruded and pelletized by the extruder reaction to form product pellets.

[0067] Among them, B1 has the following structure, x = 3, y = 2, n = 10

[0068]

[0069] B2 has the following structure, p = 4, q = 1, m = 15

[0070]

[0071] Example 4

[0072] A sweat-resistant thermoplastic polyurethane elastomer and its preparation method include the following steps:

[0073] 40 parts of PBA2000 polyol and 50 parts of MDI are respectively metered by metering pumps and then enter a mixer, react at 120 °C for 4 h, and then enter a tubular reactor through a booster pump to prepare prepolymer D4.

[0074] Prepolymer D4 enters the starting feeding port of the first zone of a twin-screw extruder. 10 parts of butanediol are metered by a metering pump and enter the second reaction zone of the twin-screw extruder. 5 parts of sweat-resistant additive B1 and 1 part of B2 are metered by metering pumps and heated to 80 °C through a temperature controller, and then enter the fifth reaction zone of the twin-screw extruder, and then are extruded and pelletized by the extruder reaction to form product pellets.

[0075] Among them, B1 has the following structure, x = 4, y = 0, n = 7

[0076]

[0077] B2 has the following structure, p = 4, q = 1, m = 15

[0078]

[0079] Example 5

[0080] A sweat-resistant thermoplastic polyurethane elastomer and its preparation method include the following steps:

[0081] 70 parts of PEA2000 polyol and 22 parts of MDI are respectively metered by metering pumps and then enter a mixer, react at 120 °C for 4 h, and then enter a tubular reactor through a booster pump to prepare prepolymer D5.

[0082] Prepolymer D5 enters the starting feeding port of the first zone of a twin-screw extruder. 8 parts of butanediol are metered by a metering pump and enter the second reaction zone of the twin-screw extruder. 0.5 part of sweat-resistant additive B1 and 0.5 part of B2 are metered by metering pumps and heated to 80 °C through a temperature controller, and then enter the sixth reaction zone of the twin-screw extruder, and then are extruded and pelletized by the extruder reaction to form product pellets.

[0083] Among them, B1 has the following structure, x = 0, y = 4, n = 7

[0084]

[0085] B2 has the following structure, p = 4, q = 0, m = 25

[0086]

[0087] Example 6

[0088] A method for preparing a sweat-resistant thermoplastic polyurethane elastomer includes the following steps:

[0089] 42 parts of PTMEG2000 polyol and 45 parts of MDI are respectively metered by metering pumps and then enter a mixer, react at 120 °C for 4 h, and then enter a tubular reactor through a booster pump to prepare prepolymer D6.

[0090] Prepolymer D6 enters the starting feeding port of the first zone of a twin-screw extruder. 13 parts of butanediol are metered by a metering pump and enter the second reaction zone of the twin-screw extruder. 1 part of sweat-resistant additive B1 and 2 parts of B2 are metered by metering pumps and heated to 80 °C through a temperature controller, and then enter the fifth reaction zone of the twin-screw extruder, and then are extruded and pelletized by the extruder reaction to form product pellets.

[0091] Among them, B1 has the following structure, x = 0, y = 4, n = 7

[0092]

[0093] B2 has the following structure, p = 4, q = 0, m = 25

[0094]

[0095] Example 7

[0096] A method for preparing a sweat-resistant thermoplastic polyurethane elastomer includes the following steps:

[0097] 68 parts of gPEA4000 polyol and 25 parts of HDI were respectively metered by metering pumps and then entered a mixer, reacted at 120°C for 4 h, and then entered a tubular reactor through a booster pump to prepare prepolymer D7.

[0098] Prepolymer D7 entered the starting feeding port of the first zone of a twin-screw extruder. 7 parts of ethylene glycol were metered by a metering pump and entered the second reaction zone of the twin-screw extruder. 6 parts of sweat-resistant additive B1 and 7 parts of B2 were metered by metering pumps and heated to 80°C through a temperature controller, and then entered the fourth reaction zone of the twin-screw extruder, and then were extruded and granulated by the extruder reaction to form product particles.

[0099] Among them, B1 has the following structure, x = 3, y = 2, n = 7

[0100]

[0101] B2 has the following structure, p = 0, q = 4, m = 12

[0102]

[0103] Comparative Example 1

[0104] Compared with Example 1, the difference is that the sweat-resistant additive B2 was not added, and others were the same.

[0105] Comparative Example 2

[0106] Compared with Example 1, the difference is that the sweat-resistant additive B1 was not added, and others were the same.

[0107] Comparative Example 3

[0108] Compared with Example 1, the difference is that the sweat-resistant additives B1 and B2 were not added, and others were the same.

[0109] Testing method

[0110] The tensile strength testing method was ASTM D412-16(2021), and the tensile rate was 500 mm / min.

[0111] A 2-mm-thick test piece was cut into a size of 2 cm * 2 cm, immersed in artificial sebum, and stored at 50°C for 7 days, and observed whether yellowing occurred.

[0112] Yellowing judgment criterion:

[0113] Degree of yellowing Evaluation There is almost no difference from the blank control when observed with the naked eye ★★★★★ The difference from the blank control can be recognized with the naked eye, but it is not obvious ★★★★ There is an obvious difference from the blank control, semi-transparent light yellow ★★★ Severe yellowing, lighter in color than artificial sebum ★★ Severe yellowing, the same color as artificial sebum ★

[0114] Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Comparative Example 1 Comparative Example 2 Comparative Example 3 Tensile strength MPa 28 32 29 35 26 31 29 29 30 29 Elongation at break % 521 460 495 530 480 530 564 552 534 555 Yellowing situation ★★★★★ ★★★ ★★★★ ★★★★★ ★★★★ ★★★ ★★★ ★★ ★★ ★

[0115] It can be found through comparison that Comparative Example 3 is a blank control, and it turns yellow very severely when soaked in hand sweat. In Comparative Examples 1 and 2, a hand-sweat-resistant additive was added, and there was a certain hand-sweat resistance effect, but it was still very yellow.

[0116] In Examples 1-7, two hand-sweat-resistant additives were added, and the yellowing of the specimens was significantly improved. However, it can be found through comparison that different raw materials need to have a suitable additive molecular composition to achieve the best effect.

[0117] It can be found by detecting the physical properties that the examples adding hand-sweat-resistant additives B1 and B2 did not reduce the strength, but instead had a slight increase, indicating that this formulation does not affect the strength while improving the hand-sweat resistance effect.

Claims

1. A thermoplastic polyurethane elastomer resistant to hand sweat, characterized in that, The elastomer is prepared from the following raw materials in the following mass ratios: Polyol, 40-70 parts, preferably 45-65 parts, Diisocyanate, 20-45 parts, preferably 25-50 parts, Chain extender, 5-15 parts, preferably 6-10 parts, Hand-sweat resistant aid B1, 0.5-8 parts, preferably 2-5 parts, Hand-sweat resistant aid B2, 0.5-8 parts, preferably 2-5 parts, Among them, the structural formula of the hand-sweat resistant aid B1 is: In the formula, x and y respectively represent natural numbers between 0 and 4, and n represents a natural number between 4 and 15, preferably a natural number between 5 and 8; Among them, the structural formula of the hand-sweat resistant aid B2 is: In the formula, p and q respectively represent natural numbers between 0 and 4, and m represents a natural number between 10 and 25, preferably a natural number between 12 and 20.

2. The elastomer according to claim 1, wherein The polyol is one or a combination of polyester polyol, polyether polyol, polycaprolactone polyol, and polycarbonate polyol; Preferably, the number-average molecular weight of the polyol is 500-6000 g / mol, preferably 1000-3000 g / mol.

3. The elastomer according to claim 1 or 2, characterized in that, The diisocyanate is one or more of aromatic diisocyanate, aliphatic diisocyanate, and alicyclic diisocyanate, preferably one or more of 4,4'-diphenylmethane diisocyanate, 2,4-diphenylmethane diisocyanate, 2,2'-diphenylmethane diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 1,5-naphthalene diisocyanate, 1,4-phenylene diisocyanate, m-xylylene diisocyanate, diphenylmethane-3,3'-dimethoxy-4,4'-diisocyanate, 1,6-hexamethylene diisocyanate, 1,10-decane diisocyanate, 1,3-cyclohexane diisocyanate, 1,4-cyclohexane diisocyanate, 2,4-hexahydrotoluene diisocyanate, 2,6-hexahydrotoluene diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, 2,2'-dicyclohexylmethane diisocyanate, 2,4-dicyclohexylmethane diisocyanate, and isophorone diisocyanate, more preferably one or more of 4,4'-diphenylmethane diisocyanate, 1,6-hexamethylene diisocyanate, 2,4-toluene diisocyanate, and 4,4'-dicyclohexylmethane diisocyanate.

4. The elastomer according to any one of claims 1 to 3, characterized in that, The chain extender is a C2-C6 aliphatic and / or alicyclic diol, preferably one or more of ethylene glycol, 1,3-propanediol, 1,2-propanediol, diethylene glycol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, 1,4-cyclohexanediol, and 1,4-cyclohexanedimethanol, more preferably 1,4-butanediol and / or 1,4-cyclohexanedimethanol.

5. A method for preparing a hand-sweat-resistant thermoplastic polyurethane elastomer, wherein the polyurethane elastomer is the elastomer according to any one of claims 1-4, characterized in that, The method is as follows: the polyol reacts with the diisocyanate to obtain a prepolymer, and the chain extender and the hand-sweat resistant aid are added for chain extension, and then the elastomer product is obtained by reactive extrusion granulation with an extruder.

6. Use of a sweat-resistant thermoplastic polyurethane elastomer, wherein the polyurethane elastomer is the elastomer described in any one of claims 1-4, or the elastomer prepared by the method described in claim 5, and the polyurethane elastomer is used for preparing polyurethane injection molded products, preferably for polyurethane injection molded products in contact with the human body, and more preferably for preparing mobile phone cases, smart wearables, and overmolded products.

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