A stain-resistant TPU composite material and a preparation method thereof

Abstract

The present application relates to a kind of stain-resistant TPU composite material, it includes thermoplastic polyurethane elastomer 50-99 parts by weight, self-repairing thermosetting polyurethane 1-50 parts by weight.The thermoplastic polyurethane composite material of the present application has excellent Mark pen resistance, oil stain resistance, cosmetic resistance and other characteristics, and the product can be applied to watch, bracelet and other smart wear fields.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of thermoplastic elastomer composites, in particular relates to a stain-resistant TPU composite material and a preparation method thereof. BACKGROUND

[0002] Thermoplastic polyurethane elastomer (TPU) is a kind of thermoplastic elastomer that can be melt processed, which maintains high elasticity in a wide range of hardness, has good mechanical strength and excellent wear resistance, in addition, TPU also has excellent oil resistance, aging resistance and low temperature resistance. However, the intermolecular polarity of TPU is large, which leads to poor performance in resisting cosmetics, Mark pens, etc.

[0003] Patent CN201710654040.1 prepared a conductive self-repairing polyurethane material, which focuses on the performance of crack sensing and self-repairing of the material under the condition of power on, and does not involve the stain resistance of the material.

[0004] Patent CN201810372884.1 prepared a self-repairing flame-retardant polyurethane, which studied the flame-retardant and self-repairing performance of the material, and did not involve the stain resistance of the material.

[0005] Therefore, in order to broaden the application field of TPU, it is necessary to solve the problem of TPU's own stain resistance. SUMMARY

[0006] The technical problem to be solved by the present application is to solve the problem of TPU's own stain resistance and broaden its application field, thereby providing a stain-resistant TPU composite material.

[0007] In order to solve the above technical problems, the present application adopts the following technical solutions:

[0008] A stain-resistant TPU composite material, the composite material comprises:

[0009] 50-99 parts by weight of thermoplastic polyurethane elastomer TPU;

[0010] 1-50 parts by weight of self-repairing thermosetting polyurethane, preferably 5-30 parts by weight.

[0011] The TPU has a hardness of 60A-80D, preferably 70A-60D, and more preferably 80A-55D;

[0012] The hard segment phase of the thermoplastic polyurethane elastomer is composed of diisocyanate and chain extender;

[0013] The diisocyanate is one or more of TDI, MDI, HMDI, HDI, PPDI, IPDI, NDI, XDI, and TODI; preferably one or more of TDI, MDI, HMDI, HDI, and IPDI;

[0014] The chain extender is a small molecule diamine and / or diol, wherein the small molecule diamine is preferably one or more of 3,3'-dichloro-4,4'-diaminodiphenyl methane, 3,5-diamino-p-chlorobenzoic acid isobutyl ester, diethyl toluene diamine, and 3,5-dimethylthio toluene diamine, and the small molecule diol is preferably one or more of 1,4-butanediol, ethylene glycol, propylene glycol, methyl propylene glycol, diethylene glycol, 1,4-cyclohexanediol, and neopentyl glycol;

[0015] The soft segment phase of the thermoplastic polyurethane elastomer is composed of a polyester polyol and / or a polyether polyol;

[0016] The polyester polyol is preferably one or more of an alkyd polyester polyol, a polycaprolactone polyol, and a polycarbonate polyol, and the polyether polyol is preferably one or more of a polypropylene oxide polyol, a polytetrahydrofuran polyol, and a copolyether polyol.

[0017] The self-repairing thermoset polyurethane is a reaction type thermoset polyurethane of which the dynamic bond type is Diels-Alder;

[0018] The hard segment phase of the thermoset polyurethane elastomer is composed of a diisocyanate and a chain extender;

[0019] The diisocyanate is one or more of TDI, MDI, HMDI, HDI, PPDI, IPDI, NDI, XDI, and TODI (3,3'-dimethyl diphenyl diisocyanate); preferably one or more of TDI, MDI, HMDI, HDI, and IPDI;

[0020] The chain extender comprises two parts, chain extender one is a Diels-Alder reaction type diol, and the structural formula is:

[0021]

[0022] Chain extender two is a small molecule diamine and / or diol, wherein the small molecule diamine is preferably one or more of 3,3'-dichloro-4,4'-diaminodiphenyl methane, 3,5-diamino-p-chlorobenzoic acid isobutyl ester, diethyl toluene diamine, and 3,5-dimethylthio toluene diamine, and the small molecule diol is preferably one or more of 1,6-hexanediol, 1,4-butanediol, ethylene glycol, propylene glycol, methyl propylene glycol, diethylene glycol, 1,4-cyclohexanediol, and neopentyl glycol;

[0023] The molar ratio of the chain extender one to the chain extender two is 1:0.05-20, preferably 1:0.2-5;

[0024] The soft segment phase of the thermosetting polyurethane elastomer is composed of polyester polyols and / or polyether polyols; the number average molecular weight of the polyester polyols and the polyether polyols is preferably 500-4000, more preferably 1000-2000;

[0025] The polyester polyols are preferably one or more of alkyd polyester polyols, polycaprolactone polyols and polycarbonate polyols, and the polyether polyols are preferably one or more of polypropylene oxide polyols, polytetrahydrofuran polyols and copolyether polyols;

[0026] The preparation method of the self-repairing thermosetting polyurethane is as follows: a diisocyanate is pre-polymerized with a polyol at a molar ratio of 1:0.6-1:0.4 to obtain a pre-polymer with NCO end groups, then a chain extender (chain extender one and chain extender two), the pre-polymer and a crosslinking agent are reacted at a molar ratio of 1:0.5-0.9:0.01-0.9 to obtain the self-repairing thermosetting polyurethane, wherein the molar amount of the pre-polymer is equal to the molar amount of the polyol;

[0027] The crosslinking agent is a diisocyanate trimer, preferably one or more of hexamethylene diisocyanate trimer (tri-HDI), toluene diisocyanate trimer (tri-TDI) and diphenylmethane diisocyanate trimer (tri-MDI).

[0028] The preparation method of the stain-resistant TPU composite material of the application comprises the following steps:

[0029] The self-repairing thermosetting polyurethane powder is mixed with TPU, and then melt-mixed through an extruder at a mixing temperature of 120-230°C, preferably 150-210°C, to obtain a composite material;

[0030] The composite material is prepared into a product through a process such as injection molding, and the product is cured at 60-80°C for 8-168h, so that the material is further cured at this temperature to obtain a product with high elasticity and stain resistance.

[0031] The self-repairing polyurethane is in a crosslinked state at room temperature, fully fixes the movement of molecular chains, reduces the movement ability of the material, and has a crosslinked network; when the material is compounded with TPU, the DA bonds of the material are broken at high temperature, the molecular weight of the material is reduced, the material can act as a plasticizer for TPU, the flowability of the material is improved, and the processing temperature is reduced; secondly, the prepared product is cured at 60-80°C, the DA bonds of the material can be reformed, part of the crosslinked network of the material is fixed, the surface tension of the material is reduced, and the permeability is increased; when a marker is used for marking, the trace of the marker does not penetrate into the interior of the material, so that the trace can be wiped clean with ethanol.

[0032] The composite material can be applied to the field of smart wear such as a bracelet, a watch and the like.

[0033] The present application has the following beneficial effects:

[0034] 1. The TPU composition has simple preparation process and is easy to operate.

[0035] 2. The prepared TPU composition has good material compatibility and good mixing effect with the matrix.

[0036] 3. The prepared TPU composition has good stain resistance and can be used in the field of smart wear. BRIEF DESCRIPTION OF DRAWINGS

[0037] Figure 1 The material stain resistance test results of Comparative Example 1-2 and Example 1-6 (from left to right). DETAILED DESCRIPTION

[0038] The present application will be further described below through specific examples. In the present application, parts, % are generally by weight, and the following materials are used in the examples:

[0039] TPU with hardness of 60A, WHT-1560, commercially available;

[0040] TPU with hardness of 80A, WHT-4075, commercially available;

[0041] TPU with hardness of 80A, WHT-1185, commercially available;

[0042] TPU with hardness of 90A, WHT-1190, commercially available;

[0043] TPU with hardness of 60D, WHT-8164, commercially available;

[0044] TPU with hardness of 80D, WHT-8280H, commercially available.

[0045] Preparation of DA small molecules:

[0046] 60g (612mmol) of maleic anhydride was weighed into a 250mL round-bottom flask equipped with a magnetic rotor, 150mL of 1,4-dioxane was added and stirred until the maleic anhydride was completely dissolved, then 45mL of furan (42.8g, 628mmol) was slowly added dropwise into the round-bottom flask, and the reaction was stirred at room temperature for 24h. After the reaction was completed, the obtained product was vacuum filtered and washed with ether three times, and dried in a vacuum oven at 45℃ for 12h to obtain a white solid product 1.

[0047] Weigh 16.5 g (271 mmol) of ethanolamine and dilute in 30 mL of anhydrous methanol. Weigh 45 g (271 mmol) of the product 1 from the previous step and dissolve in 70 mL of anhydrous methanol and add to a 250 mL round bottom flask. Slowly add the diluted ethanolamine / methanol solution to the round bottom flask using a dropping funnel while stirring until all of the ethanolamine has been added, at which point a yellow homogeneous solution is obtained. Add a reflux condenser and stir at 70 °C for 24 h under reflux. After the reaction is complete, cool the reaction to room temperature and place in a freezer overnight, at which point the product crystallizes out. Vacuum filter the crystals and wash with ether three times and dry in a vacuum oven at 45 °C for 12 h to obtain white solid product 2.

[0048] Weigh 30 g (143 mmol) of product 2 from the previous step into a 500 mL round bottom flask, add 300 mL of toluene to the round bottom flask, add a reflux condenser and reflux at 130 °C for 12 h. After the reaction is complete, filter the solution while hot and collect the filtrate, cool the filtrate to room temperature and place in a freezer overnight, at which point the product crystallizes out. Vacuum filter the crystals and wash with ether three times and dry in a vacuum oven at 45 °C for 12 h to obtain a light yellow solid product 3.

[0049] Weigh 20 g (142 mmol) of product 3 from the previous step and 14 g (143 mmol) of furfuryl alcohol into a 500 mL round bottom flask, add 200 mL of toluene to the round bottom flask, stir at 80 °C for 24 h, during which time the product precipitates out. After the reaction is complete and cooled to room temperature, vacuum filter the precipitate and wash with ether three times and dry in a vacuum oven at 45 °C for 12 h to obtain a light yellow solid product 4, the DA small molecule.

[0050] DAPU-1 Preparation Method:

[0051] The polyester polyol (PBA-1000) was pre-treated at 100 °C in a vacuum oven for 12 h to remove water; MDI and PBA were reacted at 80 °C for 2 h at a molar ratio of 1 :0.5 to obtain a -NCO terminated prepolymer. Then BDO, DA small molecule, PBA prepolymer and tri-functional tri-HDI were mixed at a molar ratio of 0.5:0.5:0.8:0.13 at 70 °C for 24 h to obtain PUDA-1.

[0052] DAPU-2 Preparation Method:

[0053] Polyester polyol (PEBA-2000) was pre-treated at 100 °C in vacuum oven for 12 h to remove water; HMDI and PEBA were reacted at 70 °C for 2 h with a molar ratio of 1 :0.55 to give a -NCO terminated prepolymer. Then HDO, DA small molecule, PEBA prepolymer and tri-functionality tri-TDI were mixed at 75 °C with a molar ratio of 0.4:0.6:0.9:0.067 for 12 h to give PUDA-2.

[0054] DAPU-3 Preparation method:

[0055] Polyether polyol (PTMEG-3000) was pre-treated at 110 °C in vacuum oven for 24 h to remove water; IPDI and PTMEG were reacted at 75 °C for 4 h with a molar ratio of 1 :0.45 to give a -NCO terminated prepolymer. Then ethylene glycol, DA small molecule, PTMEG prepolymer and tri-functionality tri-MDI were mixed at 60 °C with a molar ratio of 0.35:0.65:0.75:0.167 for 72 h to give PUDA-3.

[0056] DAPU-4 Preparation method:

[0057] Polycarbonate polyol (PCDL-2000) was pre-treated at 100 °C in vacuum oven for 12 h to remove water; TODI and PCDL were reacted at 60 °C for 24 h with a molar ratio of 1 :0.5 to give a -NCO terminated prepolymer. Then propylene glycol, DA small molecule, PCDL prepolymer and tri-functionality tri-HDI were mixed at 70 °C with a molar ratio of 0.2:0.8:0.681:0.206 for 30 h to give PUDA-4.

[0058] DAPU-5 Preparation method:

[0059] Polyester polyol (PCL-1000) was pre-treated at 100 °C in vacuum oven for 12 h to remove water; XDI and PCL were reacted at 76 °C for 5 h with a molar ratio of 1 :0.4 to give a -NCO terminated prepolymer. Then neopentyl glycol, DA small molecule, PCL prepolymer and tri-functionality tri-TDI were mixed at 90 °C with a molar ratio of 0.2:0.8:0.7:0.2 for 8 h to give PUDA-5.

[0060] DAPU-6 Preparation method:

[0061] Polyether polyol (PEG-500) was pre-treated in vacuum oven at 100℃ for 12h to remove water; NDI and PEG were reacted at 80℃ for 2h to get pre-polymer capped with -NCO at the molar ratio of 1:0.6. Then DA small molecule, PCL pre-polymer and tri-functionality tri-MDI were mixed at 90℃ for 10h to get PUDA-6 at the molar ratio of 1:0.5:0.33.

[0062] The method for preparing the composite material is as follows:

[0063] The self-repairing thermosetting polyurethane and TPU granules are mixed, and then added into an extruder for melt extrusion, granulation, to obtain the composite material.

[0064] Table 1. Raw material ratio and preparation conditions of examples 1-6 and comparative examples 1-2

[0065]

[0066]

[0067] Test of stain resistance of the material:

[0068] The surface of the material is marked with a marker (the marks are two rows, and the brand of the marker is Zebra); after standing at room temperature for 60 minutes, the lower row of marks on the material is wiped with non-woven fabric soaked with ethanol, it can be seen that the surface scratches of comparative examples 1 and 2 are difficult to wipe clean, and the surface scratches of examples 1-6 are obviously reduced, and even can be completely wiped clean.

Claims

1. A stain-resistant TPU composite material, characterized in that, The composite material includes: 50-99 parts by weight of thermoplastic polyurethane elastomer; 1-50 parts by weight of self-healing thermosetting polyurethane; The self-healing thermosetting polyurethane is a reactive thermosetting polyurethane with a Diels-Alder dynamic bond type. The chain extender used to prepare the self-healing thermosetting polyurethane comprises two parts. The first chain extender is a Diels-Alder reactive diol with the following structure: Chain extender 2 is a small molecule diamine and / or diol, and the molar ratio of chain extender 1 to chain extender 2 is 1:0.05 to 1:

20.

2. The TPU composite material according to claim 1, characterized in that: The amount of self-healing thermosetting polyurethane is 5 to 30 parts by weight.

3. The TPU composite material according to claim 1, characterized in that: The hardness of the thermoplastic polyurethane elastomer is between 60A and 80D.

4. The TPU composite material according to claim 1, characterized in that: The small molecule diamine is selected from one or more of 3,3'-dichloro-4,4'-diaminodiphenylmethane, 3,5-diamino-p-chlorobenzoate isobutyl ester, diethyltoluenediamine, and 3,5-dimethylthiotoluenediamine; the small molecule diol is selected from one or more of 1,6-hexanediol, 1,4-butanediol, ethylene glycol, propylene glycol, methylpropylene glycol, diethylene glycol, 1,4-cyclohexanediol, and neopentyl glycol. The molar ratio of chain extender one to chain extender two is 1:0.2 to 5.

5. The TPU composite material according to any one of claims 1-4, characterized in that: The preparation method of the self-healing thermosetting polyurethane includes: prepolymerizing diisocyanate with polyol to obtain a prepolymer with NCO end groups, and then reacting chain extender one and chain extender two, the prepolymer and crosslinking agent to obtain self-healing thermosetting polyurethane.

6. The TPU composite material according to claim 5, characterized in that: Diisocyanates are one or more of TDI, MDI, HMDI, HDI, PPDI, IPDI, NDI, XDI, and TODI; The polyols are selected from polyester polyols and / or polyether polyols; The molar ratio of diisocyanate to polyol is 1:0.6 to 1:0.

4.

7. The TPU composite material according to claim 6, characterized in that: The number average molecular weight of the polyester polyol and the polyether polyol is 500 to 4000. The polyester polyol is selected from one or more of alkyd polyester polyol, polycaprolactone polyol and polycarbonate polyol. The polyether polyol is selected from one or more of polyoxypropylene polyol, polytetrahydrofuran polyol and copolyether polyol.

8. The TPU composite material according to claim 5, characterized in that: The crosslinking agent is a diisocyanate trimer.

9. The TPU composite material according to claim 8, characterized in that: The crosslinking agent is one or more of hexamethylene diisocyanate trimer, toluene diisocyanate trimer, and diphenylmethane diisocyanate trimer.

10. The TPU composite material according to claim 5, characterized in that: The molar ratio of chain extender I and chain extender II, prepolymer and crosslinking agent is 1:0.5-0.9:0.01-0.

9.

11. A method for preparing the TPU composite material according to any one of claims 1-10, comprising: Self-healing thermosetting polyurethane powder is mixed with TPU and then melt-mixed through an extruder at a mixing temperature of 120–230°C to obtain a composite material.

12. The application of the TPU composite material according to any one of claims 1-10 in the field of smart wearables.

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