A waterborne polyurethane and silicone composite biomimetic material, its preparation method and application

Abstract

The present invention discloses a waterborne polyurethane and silica gel composite biomimetic material, its preparation method and application, belonging to the technical field of biomimetic skin. The biomimetic material includes a silica gel layer and a polyurethane layer. The material of the silica gel layer includes two-component silica gel, and the material of the polyurethane layer includes double-bond terminated waterborne polyurethane. The preparation method of the biomimetic material is as follows: Spray the double-bond terminated waterborne polyurethane into a mold, heat and dry it to obtain a polyurethane layer; Spray a platinum catalyst on the surface of the polyurethane layer, then mix the A component and B component of the two-component silica gel evenly and pour them into the mold, oscillate and level them, and cure and form to obtain the waterborne polyurethane and silica gel composite biomimetic material; The biomimetic material has the characteristics of high peel strength, good environmental performance, good folding resistance, high wear resistance, good heat resistance, etc., and especially has a baby-like skin-friendly touch, and has broad application prospects in artificial skin, soft robots, wearable devices, prosthetic epidermis, etc.

Description

Technical Field

[0001] The present invention belongs to the technical field of bionic skin, and particularly relates to a waterborne polyurethane and silicone composite bionic material, a preparation method thereof and an application thereof. Background Art

[0002] With the increasing demand for smart wearable devices and soft robot skins, the market for developing materials similar to human skin performance is becoming more and more urgent. Since many of the soft materials used in current wearable devices and soft robots are of the silicone type, this material has a poor surface touch, and at the same time, the surface is easily contaminated and not easy to clean, and it has obvious disadvantages both in terms of application and human-machine experience.

[0003] At present, the post-treatment of silicone at home and abroad all uses treatment agents such as solvent-based silicone feel agents. Since this treatment agent contains strong solvents, its environmental protection performance is not good, and its binding property with silicone is also not good, and it is easy to fall off and crack during later application. Therefore, developing materials that can bond firmly with silicone and have a good skin-friendly feeling is an important research field. Summary of the Invention

[0004] The purpose of the present invention is to provide a waterborne polyurethane and silicone composite bionic material, a preparation method thereof and an application thereof, so as to solve the problem of poor adhesion between silicone and skin-friendly materials in existing bionic skin materials.

[0005] To achieve the above purpose, in the first aspect of the present invention, a waterborne polyurethane and silicone composite bionic material is provided. The bionic material includes a silicone layer and a polyurethane layer. The material of the silicone layer includes two-component silicone, and the material of the polyurethane layer includes double-bond terminated waterborne polyurethane. And the silicone layer and the polyurethane layer are bonded together by a chemical reaction under the action of a platinum catalyst.

[0006] Further, the two-component silicone is an addition-cured AB two-component platinum silicone.

[0007] Further, the raw materials of the double-bond terminated waterborne polyurethane include isocyanate, polyol, hydrophilic chain extender, small molecule chain extender, end-capping agent, neutralizing agent and post-chain extender.

[0008] Further, the end-capping agent is a hydroxyl-containing double-bond compound, and preferably, the end-capping agent is a mono-hydroxy acrylate compound.

[0009] Further, the end-capping agent is at least one of hydroxyethyl methacrylate, hydroxypropyl methacrylate, hydroxypropyl acrylate, 2-hydroxy-3-phenoxypropyl acrylate and hydroxyethyl acrylate.

[0010] Further, the isocyanate is at least one of isophorone diisocyanate (IPDI), 4,4'-dicyclohexylmethane diisocyanate (HMDI), hexamethylene diisocyanate (HDI), toluene-2,4-diisocyanate (TDI), and diphenylmethane diisocyanate (MDI).

[0011] Further, the polyol is at least one of polyether polyol (PPG series), polytetrahydrofuran diol (PTMG series), polyester polyol, and polycarbonate polyol.

[0012] Further, the hydrophilic chain extender is at least one of dimethylolpropionic acid, dimethylolbutyric acid, and sulfonate-type hydrophilic chain extender.

[0013] Further, the sulfonate-type hydrophilic chain extender is a sulfonate chain extender containing active hydrogen, especially a sulfonate-type hydrophilic chain extender containing an amino group, specifically at least one of sodium ethylenediamine ethanesulfonate, 1,3-diaminobenzene-4,6-disulfonic acid, and diaminobenzenesulfonate.

[0014] Further, the small molecule chain extender is at least one of 2-methyl-1,3-propanediol (MPO), 1,4-butanediol (BDO), cyclohexanedimethanol (CHDM), and trimethylolpropane (TMP).

[0015] Further, the neutralizing agent is at least one of triethylamine, ammonia water, and sodium hydroxide, preferably triethylamine.

[0016] Further, the post-chain extender is at least one of ethylenediamine, hexamethylenediamine, and isophoronediamine.

[0017] Further, the preparation method of the double bond-terminated waterborne polyurethane includes the following steps:

[0018] Add the polyol and isocyanate into a flask, stir and react at 85 - 95 °C for 2 - 3 h, then add the hydrophilic chain extender, small molecule chain extender, and diluent, stir and react at 70 - 85 °C for 2 - 3 h, then add the catalyst and diluent, cool down to 65 - 75 °C and continue to react for 3 - 5 h, add the capping agent, keep the temperature and react for 1 - 2 h to obtain a prepolymer. Cool down the prepolymer to 40 - 50 °C, add the diluent and neutralizing agent, react for 3 - 5 min, then cool down to 10 - 15 °C, add deionized water, stir and disperse, and then add the post-chain extender for post-chain extension reaction, and then remove the diluent to obtain the double bond-terminated waterborne polyurethane.

[0019] Further, in the above preparation process, the mass ratio of polyol, isocyanate, hydrophilic chain extender, small molecule chain extender, catalyst, neutralizer, deionized water and post-chain extender is 120 - 159.2: 22.2 - 33: 4.27 - 5.9: 0.74: 0.28 - 0.35: 3.22: 279 - 350: 0.92.

[0020] Further, the ratio of the polyol to the isocyanate satisfies that the isocyanate index (the ratio of NCO / OH) is 2 - 2.8. Under this ratio relationship, the obtained polyurethane film has a relatively soft hardness and is easy to combine with the silica gel layer.

[0021] Further, the dosage of the capping agent is 0.5 - 1.5% of the sum of the masses of isocyanate, polyol, hydrophilic chain extender, small molecule chain extension, neutralizer and post-chain extender. If the content of the capping agent is too small, the obtained double bond-capped waterborne polyurethane cannot react fully with the two-component silica gel, resulting in poor bonding between the two. If the content of the capping agent is too large, it will cause an imbalance in the functional group ratio of the original two-component silica gel, thus affecting the curing and forming of the silica gel.

[0022] Further, the catalyst is an organic bismuth catalyst, preferably at least one of BCAT-E28A and BCAT-E16.

[0023] Further, the diluent is acetone and / or methyl ethyl ketone.

[0024] The second aspect of the present invention provides a preparation method of a waterborne polyurethane and silica gel composite biomimetic material, comprising the following steps:

[0025] S1. Spray the double bond-capped waterborne polyurethane into a polytetrafluoroethylene mold, heat and dry it to obtain a polyurethane layer;

[0026] S2. Spray a platinum catalyst on the surface of the polyurethane layer, then mix the A component and the B component of the two-component silica gel evenly, pour them into the polytetrafluoroethylene mold, oscillate and level them, and cure and form to obtain the waterborne polyurethane and silica gel composite biomimetic material.

[0027] Further, in step S1, the heating temperature is 80 - 120 °C, the heating time is 3 - 10 min, and the thickness of the polyurethane layer is 0.1 - 0.3 mm.

[0028] Further, the platinum catalyst is at least one of Speier catalyst, Karstedt’s catalyst and Ashby’s catalyst. Preferably, the platinum catalyst is the KP25 catalyst of Shanghai Neutron Star Chemical Technology Co., Ltd.

[0029] Further, the spraying amount of the platinum catalyst in step S2 is 12 - 20 g / m 2 , preferably 16 g / m2 If the amount of the catalyst is too small, the polyurethane layer cannot be fully combined with the two-component silica gel. If the amount of the catalyst is too large, the reaction between the polyurethane layer and the two-component silica gel is too violent, which easily causes too much surface heat of the polyurethane layer and damages the film-forming resin.

[0030] Further, in step S2, the amount of the two-component silica gel is 15-28 kg / m 2 Preferably, it is 20 kg / m 2 .

[0031] Further, in step S2, the curing and forming temperature is 20-30 °C. If the temperature is too low, the polymerization rate is too slow, which affects the reaction and forming of the polyurethane layer and the two-component silica gel. If the temperature is too high, the reaction of the two-component silica gel itself is too fast, resulting in a poor bonding degree between the two-component silica gel and the polyurethane layer.

[0032] The third aspect of the present invention provides the application of the above-mentioned waterborne polyurethane and silica gel composite biomimetic material in artificial skin, soft robots, wearable devices and prosthetic epidermis.

[0033] The beneficial effects of the present invention:

[0034] 1. The present invention provides a waterborne polyurethane and silica gel composite biomimetic material, which is formed by chemically bonding a double-bond terminated waterborne polyurethane and a two-component silica gel under the action of a platinum catalyst. It has a double-layer structure, including a silica gel layer and a polyurethane layer. The polyurethane layer exhibits the touch of baby skin, and the silica gel layer provides a soft and elastic fleshy feeling. It not only solves the problem that the surface energy of silica gel is low and it is not easy to bond and process, but also the formed material retains the soft touch of silica gel and has a skin-friendly touch like that of a baby. In addition, the peeling strength of the biomimetic material can reach 5 N / 3 cm (the tearing strength of silica gel is only 5 N), the folding resistance at room temperature can reach 100,000 times, the folding resistance at low temperature can reach 50,000 times, and the Martindale abrasion resistance can reach 100,000 times. It has the characteristics of high peeling strength, good environmental protection performance, good folding resistance performance, high wear resistance performance and good heat resistance performance, and has broad application prospects in artificial skin, soft robots, wearable devices, prosthetic epidermis and other aspects.

[0035] 2. The present invention controls the ratio of polyol to isocyanate in the preparation process of the double-bond terminated waterborne polyurethane to satisfy that the isocyanate index (the ratio of NCO / OH) is 2-2.8. Under this ratio relationship, the hardness of the obtained polyurethane film is relatively soft, which is beneficial to its collision reaction with silica gel, and the obtained polyurethane film layer is easy to combine with the silica gel layer. Otherwise, if the isocyanate index is too high, the hardness of the polyurethane film layer is too high, and the bonding property with silica gel is poor.

[0036] 3. The present invention strictly controls the dosage of the capping agent in the preparation process of the double-bond-capped waterborne polyurethane. Otherwise, if the content of the capping agent is too small, the obtained double-bond-capped waterborne polyurethane cannot react sufficiently with the two-component silica gel, resulting in poor bonding between the two. If the content of the capping agent is too large, it will cause an imbalance in the functional group ratio of the original two-component silica gel, thus affecting the curing and molding of the silica gel.

[0037] 4. The present invention strictly controls the dosage of the platinum catalyst in the preparation process of the biomimetic material. Otherwise, if the dosage of the platinum catalyst is too small, the polyurethane layer cannot be sufficiently combined with the two-component silica gel, resulting in poor bonding between the two. If the dosage of the platinum catalyst is too large, the reaction between the polyurethane layer and the two-component silica gel is too violent, easily causing too much surface heat accumulation in the polyurethane layer and damaging the film-forming resin.

[0038] 5. The present invention strictly controls the curing and molding temperature of the biomimetic material. Otherwise, if the temperature is too low, it is easy to cause too slow polymerization rate, thus affecting the reaction and molding of the polyurethane layer and the two-component silica gel. If the temperature is too high, the reaction of the two-component silica gel body is too fast, resulting in poor bonding degree between the two-component silica gel and the polyurethane layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] The present invention will be further described below with reference to the accompanying drawings.

[0040] Figure 1 It is a graph showing the test results of the peel strength of the waterborne polyurethane and silica gel composite biomimetic material obtained in Example 1 and Example 4 of the present invention;

[0041] Figure 2 It is a graph showing the test results of the peel strength of the waterborne polyurethane and silica gel composite biomimetic material obtained in Example 2 and Example 7 of the present invention;

[0042] Figure 3 It is a graph showing the test results of the peel strength of the waterborne polyurethane and silica gel composite biomimetic material obtained in Example 3 and Example 5 of the present invention;

[0043] Figure 4 It is a graph showing the test results of the peel strength of the waterborne polyurethane and silica gel composite biomimetic material obtained in Example 6 and Example 8 of the present invention;

[0044] Figure 5 It is a graph showing the test results of the peel strength of the waterborne polyurethane and silica gel composite biomimetic material obtained in Comparative Example 1 - Comparative Example 8 of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0045] In order to make the technical problems to be solved, technical solutions and beneficial effects of the present application clearer, the following further details the present application with reference to the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0046] In this application, "at least one" means one or more, and "a plurality" means two or more. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single items or plural items. For example, "at least one of a, b, or c", or "at least one of a, b, and c" can both represent: a, b, c, a~b (i.e., a and b), a~c, b~c, or a~b~c, where a, b, and c can be single or multiple respectively.

[0047] The terms used in the embodiments of this application are only for the purpose of describing specific embodiments and are not intended to limit this application. The singular forms "a", "the", and "said" used in the embodiments of this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0048] It should be understood that in various embodiments of this application, the magnitude of the serial numbers of each process does not mean the order of execution. Some or all steps can be executed in parallel or sequentially. The execution order of each process should be determined by its function and internal logic and should not constitute any limitation to the implementation process of the embodiments of this application.

[0049] The weights of the relevant components mentioned in the specification of the embodiments of this application can not only refer to the specific contents of each component, but also represent the proportional relationship of the weights between the components. Therefore, as long as the contents of the relevant components in the specification of the embodiments of this application are scaled up or down in proportion, they are within the scope disclosed in the specification of the embodiments of this application. Specifically, the mass described in the specification of the embodiments of this application can be mass units well-known in the chemical industry such as μg, mg, g, kg, etc.

[0050] Unless otherwise defined, all professional terms used hereinafter have the same meaning as commonly understood by those skilled in the art. The professional terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the protection scope of the present invention.

[0051] Unless otherwise specifically stated, various raw materials, reagents, instruments, equipment, etc. used in this application can be obtained through market purchases or can be prepared by existing methods.

[0052] The existing bionic skin material, silicone rubber, has poor adhesion with materials with good skin-friendly feeling. To solve the above problems to a certain extent, a waterborne polyurethane and silicone rubber composite bionic material is provided in the first aspect of this application. The bionic material includes a silicone rubber layer and a polyurethane layer. The material of the silicone rubber layer includes two-component silicone rubber, and the material of the polyurethane layer includes double-bond terminated waterborne polyurethane. And the silicone rubber layer and the polyurethane layer are bonded together through a chemical reaction under the action of a platinum catalyst.

[0053] In some embodiments, the two-component silicone is an addition-curing AB two-component platinum silicone.

[0054] In some embodiments, the raw materials of the double-bond terminated waterborne polyurethane include isocyanate, polyol, hydrophilic chain extender, small molecule chain extender, end-capping agent, neutralizing agent and post-chain extender.

[0055] In some embodiments, the end-capping agent is a hydroxyl group-containing double-bond compound. Preferably, the end-capping agent is a mono-hydroxy acrylate compound.

[0056] In some embodiments, the end-capping agent is at least one of hydroxyethyl methacrylate, hydroxypropyl methacrylate, hydroxypropyl acrylate, 2-hydroxy-3-phenoxypropyl acrylate and hydroxyethyl acrylate.

[0057] In some embodiments, the isocyanate is at least one of isophorone diisocyanate (IPDI), 4,4'-dicyclohexylmethane diisocyanate (HMDI), hexamethylene diisocyanate (HDI), toluene-2,4-diisocyanate (TDI) and diphenylmethane diisocyanate (MDI).

[0058] In some embodiments, the polyol is at least one of polyether polyol (PPG series), polytetrahydrofuran diol (PTMG series), polyester polyol and polycarbonate polyol.

[0059] In some embodiments, the hydrophilic chain extender is at least one of dimethylolpropionic acid, dimethylolbutyric acid and sulfonate-type hydrophilic chain extender.

[0060] In some embodiments, the sulfonate-type hydrophilic chain extender is a sulfonate chain extender containing active hydrogen, especially a sulfonate-type hydrophilic chain extender containing amino group, specifically at least one of sodium ethylenediamine ethanesulfonate, 1,3-diaminobenzene-4,6-disulfonic acid and diaminobenzenesulfonate.

[0061] In some embodiments, the small molecule chain extender is at least one of 2-methyl-1,3-propanediol (MPO), 1,4-butanediol (BDO), cyclohexanedimethanol (CHDM) and trimethylolpropane (TMP).

[0062] In some embodiments, the neutralizing agent is at least one of triethylamine, ammonia water and sodium hydroxide, preferably triethylamine.

[0063] In some embodiments, the post-chain extender is at least one of ethylenediamine, hexamethylenediamine and isophorone diamine.

[0064] In some embodiments, the preparation method of the double-bond terminated waterborne polyurethane includes the following steps:

[0065] Add polyol and isocyanate into a flask, stir and react at 85 - 95 °C for 2 - 3 h, then add hydrophilic chain extender, small molecule chain extender and diluent, stir and react at 70 - 85 °C for 2 - 3 h, then add catalyst and diluent, cool down to 65 - 75 °C and continue to react for 3 - 5 h, add capping agent, keep the temperature and react for 1 - 2 h to obtain a prepolymer. Cool down the prepolymer to 40 - 50 °C, add diluent and neutralizer, react for 3 - 5 min, then cool down to 10 - 15 °C, add deionized water, stir and disperse, then add post-chain extender for post-chain extension reaction, and then remove the diluent to obtain the double bond-capped waterborne polyurethane.

[0066] In some embodiments, during the above preparation process, the mass ratio of polyol, isocyanate, hydrophilic chain extender, small molecule chain extender, catalyst, neutralizer, deionized water and post-chain extender is 120 - 159.2 : 22.2 - 33 : 4.27 - 5.9 : 0.74 : 0.28 - 0.35 : 3.22 : 279 - 350 : 0.92.

[0067] In some embodiments, the ratio of polyol to isocyanate satisfies that the isocyanate index (the ratio of NCO / OH) is 2 - 2.8. In exemplary embodiments, it can be 2, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8 and other typical but non-limiting isocyanate indices or the range between any two isocyanate indices. The polyurethane film obtained within this isocyanate index range is relatively soft in hardness and is easy to combine with the silica gel layer.

[0068] In some embodiments, the dosage of the capping agent is 0.5 - 1.5% of the sum of the masses of isocyanate, polyol, hydrophilic chain extender, small molecule chain extender, neutralizer and post-chain extender. In exemplary embodiments, it can be 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, 1.2%, 1.3%, 1.4%, 1.5% and other typical but non-limiting mass percentages or the range between any two mass percentages. In this case, the double bond-capped waterborne polyurethane obtained can react fully with the two-component silica gel and does not affect the curing and molding of the silica gel.

[0069] In some embodiments, the catalyst is an organic bismuth catalyst, preferably at least one of BCAT-E28A and BCAT-E16.

[0070] In some embodiments, the diluent is acetone and / or methyl ethyl ketone.

[0071] The second aspect of the present application provides a preparation method of a waterborne polyurethane and silica gel composite biomimetic material, including the following steps:

[0072] S1. Spray the double-bond terminated waterborne polyurethane into a polytetrafluoroethylene mold, heat and dry it to obtain a polyurethane layer.

[0073] S2. Spray a platinum catalyst onto the surface of the polyurethane layer, then mix the A and B components of the two-component silicone evenly and pour them into the polytetrafluoroethylene mold, shake and level them, and cure and form to obtain the waterborne polyurethane and silicone composite biomimetic material.

[0074] In some embodiments, in step S1, the heating temperature is 80 - 120 °C, the heating time is 3 - 10 min, and the thickness of the polyurethane layer is 0.1 - 0.3 mm.

[0075] In some embodiments, the spraying amount of the platinum catalyst in step S2 is 12 - 20 g / m 2 , and in exemplary cases, it can be 12 g / m 2 , 13 g / m 2 , 14 g / m 2 , 15 g / m 2 , 16 g / m 2 , 17 g / m 2 , 18 g / m 2 , 19 g / m 2 , 20 g / m 2 and other typical but non-limiting spraying amounts or ranges between any spraying amounts. In this case, the polyurethane layer and the two-component silicone are fully combined and the state of the polyurethane layer is good.

[0076] In some embodiments, the platinum catalyst is at least one of Speier catalyst, Karstedt’s catalyst, and Ashby’s catalyst. Preferably, the platinum catalyst is the KP25 catalyst of Shanghai Neutron Star Chemical Technology Co., Ltd.

[0077] In some embodiments, the amount of the two-component silicone used in step S2 is 15 - 18 kg / m 2 .

[0078] In some embodiments, the curing and forming temperature in step S2 is 20 - 30 °C. In exemplary cases, it can be 21 °C, 22 °C, 23 °C, 24 °C, 25 °C, 26 °C, 27 °C, 28 °C, 29 °C, 30 °C and other typical but non-limiting temperatures or ranges between any two temperatures. In this temperature range, the reaction rate between the polyurethane layer and the two-component silicone is moderate, and the quality of the obtained biomimetic material is good.

[0079] The third aspect of the present application provides the application of the above-mentioned waterborne polyurethane and silicone composite biomimetic material in artificial skin, soft robots, wearable devices, and prosthetic epidermis.

[0080] The technical solution of the present application will be described below through specific examples and comparative examples.

[0081] Example 1

[0082] A preparation method of a waterborne polyurethane and silica gel composite bionic material. The isocyanate index of polyol and isocyanate in the preparation process of double-bond terminated waterborne polyurethane is 2.5, and the method includes the following steps:

[0083] (1) Add 120 g of polytetrahydrofuran polyol (molecular weight 3000) and 22.2 g of isophorone diisocyanate into a flask, stir and react at 90 °C for 2 h, then add 4.27 g of dimethylolpropionic acid, 0.74 g of 1,4-butanediol and 15 g of acetone, stir and react at 80 °C for 2 h. After that, add 0.28 g of organic bismuth catalyst BCAT-E28A and 10 g of acetone, cool down to 70 °C and continue to react for 3 h. Add 1.47 g of hydroxyethyl methacrylate, keep the temperature and react for 1 h to obtain a prepolymer. Cool the prepolymer to 50 °C, add 110 g of acetone and 3.22 g of triethylamine, react for 5 min, then cool down to 10 °C, add 279 g of deionized water, stir and disperse at a speed of 2000 r / m for 10 min, and then add 0.92 g of ethylenediamine and stir and react for 30 min. Remove acetone to obtain the double-bond terminated waterborne polyurethane;

[0084] (2) Spray the double-bond terminated waterborne polyurethane into a polytetrafluoroethylene mold, and heat it at 80 °C for 10 min to obtain a polyurethane layer with a thickness of 0.1 mm;

[0085] (3) Spray and spread the KP25 catalyst of Shanghai Neutron Star Chemical Technology Co., Ltd. on the surface of the polyurethane layer. The spraying amount of the KP25 catalyst is 16 g / m 2 , then mix the A component and B component of the two-component silica gel evenly and pour them into the polytetrafluoroethylene mold, oscillate and level them. The dosage of the two-component silica gel is 20 kg / m 2 , and cure at 25 °C for 10 h to obtain the waterborne polyurethane and silica gel composite bionic material.

[0086] The two-component silica gel is an addition-cured AB two-component platinum silica gel with the model MCD800013A produced by Foshan Mingchen Organosilicon Co., Ltd., including an A component and a B component, and the mass ratio of the A component to the B component is 1:1.

[0087] Example 2

[0088] A preparation method of a waterborne polyurethane and silica gel composite bionic material. The isocyanate index of polyol and isocyanate in the preparation process of double-bond terminated waterborne polyurethane is 2.0, and the method includes the following steps:

[0089] (1) Add 150 g of polytetrahydrofuran polyol (molecular weight 3000) and 22.2 g of isophorone diisocyanate into a flask, stir and react at 85 °C for 2 h, then add 4.84 g of dimethylolpropionic acid, 0.74 g of 1,4-butanediol and 15 g of acetone, stir and react at 70 °C for 3 h. After that, add 0.30 g of organic bismuth catalyst BCAT-E28A and 10 g of acetone, cool down to 65 °C and continue to react for 5 h. Add 1.47 g of hydroxyethyl methacrylate, keep the temperature and react for 1 h to obtain a prepolymer. Cool down the prepolymer to 40 °C, add 110 g of acetone and 3.22 g of triethylamine, react for 3 min, then cool down to 10 °C, add 279 g of deionized water, stir and disperse at a speed of 3000 r / m for 15 min, and then add 0.92 g of ethylenediamine and stir and react for 30 min. Remove acetone to obtain the double bond-terminated waterborne polyurethane;

[0090] (2) Spray the double bond-terminated waterborne polyurethane into a polytetrafluoroethylene mold and heat at 100 °C for 5 min to obtain a polyurethane layer with a thickness of 0.2 mm;

[0091] (3) Spray and spread the KP25 catalyst of Shanghai Neutron Star Chemical Technology Co., Ltd. on the surface of the polyurethane layer, and the spraying amount of the KP25 catalyst is 16 g / m 2 , then mix the A component and B component of the two-component silicone evenly and pour them into a polytetrafluoroethylene mold, oscillate and level them. The dosage of the two-component silicone is 20 kg / m 2 , cure at 25 °C for 10 h to obtain the waterborne polyurethane and silicone composite biomimetic material.

[0092] The composition of the two-component silicone is the same as that in Example 1.

[0093] Example 3

[0094] A preparation method of a waterborne polyurethane and silicone composite biomimetic material. The isocyanate index of the polyol and isocyanate in the preparation process of the double bond-terminated waterborne polyurethane is 2.8, and it includes the following steps:

[0095] (1) Add 159.2 g of polytetrahydrofuran polyol (molecular weight 3000) and 33 g of isophorone diisocyanate into a flask, stir and react at 95 °C for 3 h. Then add 5.9 g of dimethylolpropionic acid, 0.74 g of 1,4-butanediol and 15 g of acetone, stir and react at 85 °C for 2 h. After that, add 3.5 g of organic bismuth catalyst BCAT-E28A and 10 g of acetone, cool down to 75 °C and continue to react for 3 h. Add 1.47 g of hydroxyethyl methacrylate, keep the temperature and react for 1 h to obtain a prepolymer. Cool down the prepolymer to 50 °C, add 110 g of acetone and 3.22 g of triethylamine, react for 5 min. Then cool down to 15 °C, add 350 g of deionized water, stir and disperse at a speed of 3500 r / m for 20 min, and then add 0.92 g of ethylenediamine and stir and react for 30 min. Remove acetone to obtain the double bond-terminated waterborne polyurethane;

[0096] (2) Spray the double bond-terminated waterborne polyurethane into a polytetrafluoroethylene mold and heat at 120 °C for 3 min to obtain a polyurethane layer with a thickness of 0.3 mm;

[0097] (3) Spray and spread the KP25 catalyst of Shanghai Neutron Star Chemical Technology Co., Ltd. on the surface of the polyurethane layer. The spraying amount of the KP25 catalyst is 16 g / m 2 , and then mix the A component and B component of the two-component silicone evenly and pour them into the polytetrafluoroethylene mold, shake and level. The dosage of the two-component silicone is 20 kg / m 2 , cure at 20 °C for 10 h to obtain the waterborne polyurethane and silicone composite biomimetic material.

[0098] The composition of the two-component silicone is the same as that in Example 1.

[0099] Example 4

[0100] A preparation method of a waterborne polyurethane and silicone composite biomimetic material, compared with Example 1, the difference is only that the dosage of hydroxyethyl methacrylate in Example 1 is adjusted from "1.47 g" to "0.76 g".

[0101] Example 5

[0102] A preparation method of a waterborne polyurethane and silicone composite biomimetic material, compared with Example 1, the difference is only that the dosage of hydroxyethyl methacrylate in Example 1 is adjusted from "1.47 g" to "2.27 g".

[0103] Example 6

[0104] A preparation method of a waterborne polyurethane and silicone composite biomimetic material, compared with Example 1, the difference is only that the dosage of platinum catalyst in Example 1 is adjusted from "the spraying amount of platinum catalyst is 16 g / m 2 " to "the spraying amount of platinum catalyst is 12 g / m2 ”.

[0105] Example 7

[0106] A preparation method of a waterborne polyurethane and silica gel composite biomimetic material, compared with Example 1, the difference is only that the dosage of the platinum catalyst in Example 1 is changed from "the spraying amount of the platinum catalyst is 16 g / m 2 " to "the spraying amount of the platinum catalyst is 20 g / m 2 ".

[0107] Example 8

[0108] A preparation method of a waterborne polyurethane and silica gel composite biomimetic material, compared with Example 1, the difference is only that the dosage of the platinum catalyst in step (3) of Example 1 is changed from "cured at 25 °C for 10 h" to "cured at 30 °C for 10 h".

[0109] Comparative Example 1

[0110] A preparation method of a waterborne polyurethane and silica gel composite biomimetic material, compared with Example 1, the difference is only that 2-hydroxyethyl methacrylate in step (1) of Example 1 and KP25 catalyst in step (3) are removed.

[0111] Comparative Example 2

[0112] A preparation method of a waterborne polyurethane and silica gel composite biomimetic material, compared with Example 1, the difference is only that 2-hydroxyethyl methacrylate in step (1) of Example 1 is removed.

[0113] Comparative Example 3

[0114] A preparation method of a waterborne polyurethane and silica gel composite biomimetic material, compared with Example 1, the difference is only that the KP25 catalyst in step (3) of Example 1 is removed.

[0115] Comparative Example 4

[0116] A preparation method of a waterborne polyurethane and silica gel composite biomimetic material, compared with Example 1, the difference is only that the isocyanate index of polyol and isocyanate in the preparation process of double bond-terminated waterborne polyurethane is 3.5, that is, the dosage of isophorone diisocyanate in Example 1 is changed from "22.2 g" to "31.08 g".

[0117] Comparative Example 5

[0118] A preparation method of a waterborne polyurethane and silica gel composite biomimetic material, compared with Example 6, the difference is only that the dosage of the platinum catalyst in Example 6 is changed from "the spraying amount of the platinum catalyst is 12 g / m 2 " to "the spraying amount of the platinum catalyst is 10 g / m2 ”.

[0119] Comparative Example 6

[0120] A preparation method of a waterborne polyurethane and silica gel composite bionic material, compared with Example 7, the difference is only that the amount of platinum catalyst in Example 7 is changed from "the spraying amount of platinum catalyst is 20 g / m 2 " to "the spraying amount of platinum catalyst is 22 g / m 2 ".

[0121] Comparative Example 7

[0122] A preparation method of a waterborne polyurethane and silica gel composite bionic material, compared with Example 3, the difference is only that the amount of platinum catalyst in step (3) of Example 3 is changed from "cured at 20 °C for 10 h" to "cured at 15 °C for 10 h".

[0123] Comparative Example 8

[0124] A preparation method of a waterborne polyurethane and silica gel composite bionic material, compared with Example 8, the difference is only that the amount of platinum catalyst in step (3) of Example 8 is changed from "cured at 30 °C for 10 h" to "cured at 35 °C for 10 h".

[0125] The peel strength of the waterborne polyurethane and silica gel composite bionic materials obtained in Examples 1 - 8 and Comparative Examples 1 - 8 was tested. The test reference standard was GB / T8808 - 1988 "Test Method for Peel of Flexible Composite Plastic Materials". The test results are as Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 and shown in Table 1;

[0126] Table 1

[0127]

[0128] Combined with Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 and the test results in Table 1, it can be seen that, compared with Comparative Examples 1 - 8, the waterborne polyurethane and silica gel composite bionic materials prepared in Examples 1 - 8 have higher peel strength. The specific analysis is as follows:

[0129] Comparative Examples 1 and 2 show that conventional waterborne polyurethane (without end-capping treatment) has almost no bonding with silicone, that is, whether the conventional waterborne polyurethane is sprayed with platinum catalyst or not, it can hardly bond with silicone; Comparative Example 3 is a bonding test of end-capped double-bond waterborne polyurethane with silicone, and the results show that when the platinum catalyst is not sprayed, the bonding performance of the end-capped double-bond waterborne polyurethane with silicone is also poor;

[0130] It can be seen from the test results of Example 1 and Comparative Example 4 that, due to the hardness of the waterborne polyurethane design, its bonding performance with silica gel is average even under the catalytic action of an equal amount of platinum catalyst on the surface;

[0131] It can be seen from the test results of Example 6 and Comparative Example 5 that the waterborne polyurethane cannot be combined with the silica gel because the amount of platinum catalyst used in Comparative Example 5 is too small;

[0132] It can be seen from the test results of Example 7 and Comparative Example 6 that in Comparative Example 6, the amount of platinum catalyst used was too much, and the water-based polyurethane reacted too violently with the silica gel, resulting in too much heat accumulation on the surface of the polyurethane and damage to the film-forming resin. Not only was the surface of the molded skin damaged by excessive heat accumulation, resulting in black damage, but also its peel strength was reduced;

[0133] It can be seen from the test results of Example 3 and Comparative Example 7 that the curing temperature of the silicone in Comparative Example 7 is 15°C. Too low a temperature can easily lead to too slow a polymerization rate, thereby affecting the reaction molding of the double-bond polyurethane and the silicone, resulting in low peel strength of the two combinations;

[0134] It can be seen from the test results of Example 8 and Comparative Example 8 that the curing temperature of the silicone in Comparative Example 8 is 35°C. If the temperature is too high, the silicone body will react too quickly, and the silicone and double-bond polyurethane will not react easily, resulting in low peel strength of the two combinations.

[0135] Since Examples 1 to 8 are tests for the combination of end-capped double-bond waterborne polyurethane and silicone, the waterborne polyurethane is designed to be soft, and the platinum catalyst on the film-forming surface promotes the reaction between the double-bond waterborne polyurethane and silicone, so its peeling strength is high, and its peeling is the peeling strength that destroys the substrate, because the tear strength of silicone is only 5N, so the data can only be tested to reach 5N / 3cm, because the bottom silicone has been torn, so the chain segment is relatively soft. Waterborne polyurethane and platinum catalyst sprayed on the film-forming surface are two key technologies for firmly compounding end-capped double-bond waterborne polyurethane and silicone. Since a thin layer of waterborne polyurethane coating is compounded on the surface of silicone, it not only changes the shortcomings of silicone that is easy to penetrate oil and has a poor touch, but also can be high on the surface of waterborne polyurethane, and its surface can be subjected to many surface treatments, so that a variety of silicone composite materials with different hand feelings and functions can be obtained, and in addition, the material has a touch that is very close to the skin.

[0136] The waterborne polyurethane and silicone composite biomimetic materials obtained in Examples 1 - 8 were subjected to flex resistance at room temperature, flex resistance at low temperature, odor test and Martindale abrasion resistance test according to relevant standards, and the results are shown in Table 2:

[0137] Table 2

[0138]

[0139] As can be seen from Table 2, the waterborne polyurethane and silicone composite biomimetic materials obtained in Examples 1 - 8 passed the flex resistance at room temperature, flex resistance at low temperature and Martindale abrasion resistance test, indicating that they fully meet the qualified use standards. Therefore, they have broad application prospects in artificial skin, soft robots, wearable devices, prosthetic epidermis, etc.

[0140] It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non - exclusive inclusion, so that a process, method, article or device comprising a series of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article or device.

[0141] Although the embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A waterborne polyurethane and silicone composite bionic material, characterized in that: It comprises a silicone layer and a polyurethane layer, wherein the material of the silicone layer comprises two-component silicone, the material of the polyurethane layer comprises double-bond terminated waterborne polyurethane, and the silicone layer and the polyurethane layer are bonded together by chemical reaction under the action of a platinum catalyst; The raw materials of the double-bond terminated waterborne polyurethane include isocyanate, polyol, hydrophilic chain extender, small molecule chain extender, end-capping agent, neutralizing agent and post-chain extender; The ratio of the polyol to the isocyanate satisfies an isocyanate index of 2-2.8; The preparation method of the waterborne polyurethane and silica gel composite bionic material comprises the following steps: S1, spraying the double-bond terminated waterborne polyurethane into the mold, heating and drying to obtain a polyurethane layer; S2, spraying a platinum catalyst onto the surface of the polyurethane layer, then evenly mixing component A and component B of the two-component silicone, pouring them into a mold, shaking and flattening them, and curing and molding them to obtain the waterborne polyurethane and silicone composite bionic material; The spraying amount of platinum catalyst in step S2 is 12-20g / m 2 ; The curing temperature in step S2 is 20-30°C.

2. The waterborne polyurethane and silicone composite bionic material according to claim 1, characterized in that: The two-component silicone is an addition-type AB two-component platinum silicone.

3. The waterborne polyurethane and silicone composite bionic material according to claim 1, characterized in that: The end-capping agent is at least one of hydroxyethyl methacrylate, hydroxypropyl methacrylate, hydroxypropyl acrylate, 2-hydroxy-3-phenoxypropyl acrylate and hydroxyethyl acrylate.

4. The waterborne polyurethane and silicone composite bionic material according to claim 1, characterized in that: The amount of the end-capping agent is 0.5-1.5% of the total mass of the isocyanate, the polyol, the hydrophilic chain extender, the small molecule chain extender, the neutralizer and the post-chain extender.

5. The waterborne polyurethane and silicone composite bionic material according to claim 1, characterized in that , the platinum catalyst is at least one of a Speier catalyst, a Karstedt's catalyst and an Ashby's catalyst.

6. Use of a waterborne polyurethane and silicone composite bionic material according to any one of claims 1 to 5, characterized in that: The waterborne polyurethane and silicone composite bionic material is used in artificial skin, soft robots, wearable devices and prosthetic epidermis.

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