TPE waterborne polyurethane type bionic robot skin material and preparation method thereof

Abstract

The application belongs to the technical field of bionic skin material preparation, and specifically provides a TPE water-based polyurethane type bionic robot skin material and a preparation method thereof. The bionic skin material is composed of a water-based polyurethane synthetic leather skin layer, a thermoplastic elastomer TPE layer (foamed TPE layer) and a heating film. The epidermal water-based polyurethane material provides a baby skin touch, the middle layer TPE provides a soft and elastic meat feeling, and the lowermost layer heating film can endow the bionic skin material with a warm feeling. The bionic skin material preparation method of the application adopts a hot pressing process, solves the difficulty that the TPE surface energy is low and cannot be glued, and does not change the soft and elastic hand feeling of the TPE; the hot-pressed water-based polyurethane synthetic leather solves the problems that the traditional TPE material is prone to oil penetration and has an odor; the middle layer can adopt foamed TPE, and the lightweight function of the material can be realized; and the bionic skin material has a wide application prospect in the fields of artificial skin, soft robot, wearable device, soft toy and artificial limb skin, etc.

Description

Technical Field

[0001] This invention belongs to the field of biomimetic skin material preparation technology, specifically providing a TPE waterborne polyurethane biomimetic robot skin material and its preparation method. Background Technology

[0002] With the development of wearable devices, companion robots, and soft toys, the demand for biomimetic skin materials with better skin-friendliness is increasing. Currently, the main soft materials on the market are TPE and silicone. Products made from these two materials have a rough feel and poor skin-friendliness. Furthermore, TPE materials have limited market applications due to their tendency to seep oil and their odor. Silicone materials, due to their high density, require high-quality manufacturing and are unsuitable for making larger skin materials. Therefore, developing materials with good skin-friendliness and low density will promote the development of wearable devices, companion robots, and soft toys. Summary of the Invention

[0003] One of the objectives of this invention is to provide a method for preparing a TPE waterborne polyurethane biomimetic robot skin material. The material prepared by this method has a skin feel similar to that of a baby's skin, while retaining the soft and elastic properties of TPE material. It also has a built-in heating film system to provide human-like body temperature. This material will be the preferred molding material for wearable devices, companion robots, and soft toys.

[0004] To achieve the above objectives, the present invention adopts the following technical solution: a method for preparing a biomimetic robot skin material, comprising the following steps:

[0005] S1. Lay the heating film flat and coat it with a layer of molten thermoplastic elastomer, TPE, with a coating thickness of 1-3cm.

[0006] Alternatively, a molten thermoplastic elastomer, TPE, can be prepared first, and then the molten TPE can be foamed by 1-3 times through a foaming process to obtain foamed TPE. The heating film can be laid flat, and a layer of foamed TPE can be coated on the heating film with a coating thickness of 1-3 cm.

[0007] S2. Then, a layer of water-based polyurethane synthetic leather with a thickness of 2-5mm is coated on the molten TPE or foamed TPE, and after hot pressing and cooling, the composite material is obtained.

[0008] S3. A layer of surface treatment agent is sprayed onto the surface of the water-based polyurethane synthetic leather in the composite material and dried at 100-120℃ to obtain the biomimetic robot skin material.

[0009] Further improvements to the preparation method of TPE waterborne polyurethane biomimetic robotic skin material:

[0010] Preferably, the thermoplastic elastomer (TPE) is filled with filler oil, and the mass ratio of the raw material SEBS to the filler oil in preparing the TPE is 1 / 12-1 / 8, and the density of the TPE is 0.82-0.88 g / cm³. 3 The melt flow index is 120-200 g / 10 min. SEBS is a linear triblock copolymer with polystyrene as the end block and ethylene-butene copolymer obtained by hydrogenation of polybutadiene as the middle elastic block.

[0011] Preferably, the waterborne polyurethane resin in the waterborne polyurethane synthetic leather has a foaming ratio of 2-4 times, a tensile strength of 20-40 MPa, a modulus of 0.8-1.5 MPa, and an elongation at break of 500%-900%.

[0012] Preferably, the waterborne polyurethane resin in the waterborne polyurethane synthetic leather is an easily foaming waterborne polyurethane resin or a waterborne polyurethane fabric resin.

[0013] Preferably, the waterborne polyurethane resin in the waterborne polyurethane synthetic leather is one of the resins KT650, KT750, and KT621 from Hefei Ketian Waterborne Technology Co., Ltd.

[0014] Preferably, the waterborne polyurethane synthetic leather is prepared as follows: waterborne polyurethane resin is foamed to a ratio of 2-4, then coated onto a four-way stretch fabric, and then dried and shaped at a temperature of 70-90°C to obtain waterborne polyurethane synthetic leather.

[0015] Preferably, the heating film contains a fold-resistant copper wire nonwoven heating film system, and the surface treatment agent is a silicon-containing surface treatment agent.

[0016] Preferably, the hot pressing temperature in step S2 is 160-180℃, the pressure is 0.15Kpa-2Kpa, and the time is 5-30min.

[0017] Preferably, the foaming process in step S1 involves adding a foaming agent for mechanical foaming. The foaming agent is an expandable microsphere foaming agent, and the addition ratio in the TPE material is 0.5-1.5 wt%, with a stirring rate of 2500-4000 r / min.

[0018] The second objective of this invention is to provide a TPE waterborne polyurethane biomimetic robot skin material prepared by the above-mentioned preparation method.

[0019] The advantages of this invention compared to the prior art are as follows:

[0020] 1) The TPE waterborne polyurethane biomimetic skin material of this invention consists of waterborne polyurethane synthetic leather, a TPE layer (obtained by coating a molten or foamed TPE layer), and a heating film. The waterborne polyurethane synthetic leather is a synthetic leather prepared through a foaming process. This material is soft, and the surface-treated waterborne polyurethane synthetic leather has an excellent skin-friendly feel, giving the biomimetic skin material the tactile feel of infant skin, thus acting as the epidermis of soft skin. The TPE layer (foamed TPE) is filled with a certain amount of filler oil material, making it soft and elastic. The bottom heating film system can provide the material with human-like body temperature, bringing the machine closer to the human. It has broad application prospects in artificial skin, soft robots, wearable devices, soft toys, and prosthetic limb epidermis. Using foamed TPE as the intermediate layer gives the biomimetic skin material a lightweight function, thereby meeting the needs of manufacturing large-area objects.

[0021] 2) TPE has a very low surface energy, making it almost impossible for adhesives to bond. Even when adhesives are used, they are solvent-based instant adhesives with extremely poor environmental performance. Furthermore, the resulting adhesive is generally very hard, which compromises the leather-like appearance and the feel of the TPE, causing the product to harden and lose its soft, elastic texture, resulting in a significant difference from real skin. This invention produces a TPE biomimetic skin material or a foamed TPE biomimetic skin material by hot-pressing a water-based polyurethane synthetic leather, a TPE layer (foamed TPE layer), and a heating film. The use of foamed TPE in the middle layer enables the material to be lightweight; the use of a heating film system containing fold-resistant copper wire nonwoven fabric provides the biomimetic skin material with temperature-sensitive properties. This processing technology solves the problem of TPE's low surface energy making it difficult to bond without altering its soft, elastic feel; the hot-pressed water-based polyurethane synthetic leather solves the problems of traditional TPE materials being prone to oil seepage and odor. It has broad application prospects in artificial skin, soft robots, wearable devices, soft toys, and prosthetic skin. Attached Figure Description

[0022] Figure 1 This is a structural diagram of the TPE waterborne polyurethane biomimetic robot skin material prepared in Examples 2 and 3.

[0023] Figure 2 This is a temperature curve of the TPE-type biomimetic skin material prepared in Example 2 after heating for 24 hours. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0025] The manufacturers and models of the raw materials used in the following examples are as follows:

[0026] The heating film is the RSHP-07 model heating film from Zhejiang Hangzhou Risheng Electric Heating Products Co., Ltd.

[0027] The thermoplastic elastomer (TPE) is product 600TC-085C manufactured by Dongguan Jiayang Rubber & Plastics Co., Ltd., and the filler oil in the thermoplastic elastomer (TPE) is cosmetic-grade white mineral oil.

[0028] The waterborne polyurethane in the waterborne polyurethane synthetic leather is product model KT650 manufactured by Hefei Ketian Waterborne Technology Co., Ltd.

[0029] The TPE foaming agent is product EM046 manufactured by Nippon Yushi Pharmaceutical Co., Ltd.

[0030] The surface treatment agent is product T026 manufactured by Starr Technologies (China) Co., Ltd.

[0031] Example 1

[0032] This embodiment provides a method for preparing a traditional TPE material, which specifically includes the following steps:

[0033] Weigh 300g of TPE material into a flat-bottomed tray. The mass ratio of the filler oil in the TPE material is 1:8. Then place the flat-bottomed tray on a heating plate and control the heating temperature at 200℃. Heat for half an hour to make the TPE melt. Then pour the molten TPE into a 15cm*15cm square mold to cool and solidify, and you can get the traditional TPE product.

[0034] Example 2

[0035] This embodiment provides a method for preparing a TPE waterborne polyurethane biomimetic skin material, which specifically includes the following steps:

[0036] S1. First, weigh 500g of KT650 resin, then adjust the foaming ratio to 3 using mechanical foaming, and finally use a 300mm filament rod to coat the foamed sample onto a 60*40cm four-way stretch fabric. Dry and shape it at 80℃ to obtain water-based polyurethane synthetic leather with a thickness of 4mm.

[0037] S2. Weigh 2.5 kg of TPE material into a flat-bottomed tray. The mass ratio of the filler oil in the TPE material is 1:8. Then place the flat-bottomed tray on a heating plate and heat it at 200℃ for 50 minutes to ensure that the TPE is completely melted.

[0038] A 60*40cm heating film is laid on a 60*40cm flat tray. Then, molten TPE is coated on the heating film with a coating thickness of 2cm. When the surface temperature of TPE reaches 170℃, the prepared waterborne polyurethane synthetic leather is hot-pressed onto the surface of molten TPE. The hot-pressing pressure is 0.3Kpa and the hot-pressing time is 25min. Finally, it is cooled and solidified to obtain TPE-type biomimetic skin material.

[0039] S3. Spray a layer of Stahl's silicone-containing surface treatment agent T026 onto the surface of the TPE type biomimetic skin material, and dry it at 120℃ for 2 minutes. Finally, a baby-skin-like TPE type biomimetic skin material can be obtained.

[0040] The TPE biomimetic skin material was heated for 24 hours after being plugged in. Then, the skin surface temperature was measured every 2 hours using a Delixi temperature gun. The measured temperature data were compiled and plotted, and the temperature display was as follows: Figure 2 As shown, by Figure 2 It is known that the bionic skin of the present invention can provide functions close to human body temperature, and the temperature remains basically constant. Therefore, the skin material has temperature-sensing properties similar to human skin.

[0041] Example 3

[0042] This embodiment provides a method for preparing a foamed TPE waterborne polyurethane biomimetic skin material, which specifically includes the following steps:

[0043] S1. First, weigh 500g of KT650 resin, then adjust the foaming ratio to 3 using mechanical foaming, and finally use a 300mm filament rod to coat the foamed sample onto a 60*40cm four-way stretch fabric. Dry and shape it at 80℃ to obtain water-based polyurethane synthetic leather with a thickness of 4mm.

[0044] S2. Weigh 2.5 kg of TPE material into a flat-bottomed tray. The mass ratio of filler oil in the TPE material is 1:8. Then place the flat-bottomed tray on a heating plate and heat it at 200℃ for 50 minutes to ensure that the TPE is completely melted. Then pour the molten TPE into a mixing tank, add 20 g of TPE foaming agent, and then stir and foam at 3000 r / min. The foaming ratio is 2 times.

[0045] S3. Lay a 60*40cm heating film on a 60*40cm flat tray, then coat the foamed TPE on the heating film with a coating thickness of 2cm. When the surface temperature of the TPE reaches 170℃, hot-press the prepared water-based polyurethane synthetic leather onto the surface of the molten TPE. The hot-pressing pressure is controlled at 0.3Kpa and the hot-pressing time is 25min. Finally, cool and solidify to obtain the foamed TPE type biomimetic skin material.

[0046] S4. Spray a layer of Stahl's silicone-containing surface treatment agent T026 onto the surface of the foamed TPE biomimetic skin material, and dry it at 120℃ for 2 minutes. Finally, a baby-skin-like TPE biomimetic skin material can be obtained.

[0047] We conducted odor tests on the three products respectively, referring to the standard QBT5447-2019. The test results are shown in Table 1.

[0048] Table 1. Odor test results of samples from the three examples.

[0049] Example Odor rating Example 1 4 Example 2 1 Example 3 2

[0050] We conducted softness tests on the three products respectively, referring to ASTM D 2240. The test results are shown in Table 2:

[0051] Results of softness test of TPE materials prepared in Examples 1-3

[0052] Example Softness (shoreA) Example 1 86F Example 2 89F Example 3 90F

[0053] The results of graphic and odor tests show that Example 1 not only had white mineral oil seepage on its surface, but also emitted a pungent odor. In contrast, Examples 2 and 3 had smooth surfaces with no oil seepage and almost no odor. Hardness tests indicate that the introduction of the waterborne polyurethane outer layer did not alter the material's softness; therefore, the material is not only soft and elastic but also has excellent skin-friendly properties. The TPE waterborne polyurethane biomimetic skin material preparation method provided by this invention employs a hot-pressing process, solving the problem of TPE's low surface energy preventing adhesion. Moreover, this hot-pressing process does not alter the soft and elastic feel of TPE. Because a layer of waterborne polyurethane synthetic leather is hot-pressed onto the surface of the biomimetic skin material, it solves the problems of traditional TPE materials being prone to oil seepage and odor. The use of foamed TPE in the middle layer of the biomimetic skin material achieves lightweight functionality. Therefore, biomimetic skin materials have broad application prospects in artificial skin, soft robots, wearable devices, soft toys, and prosthetic skin.

[0054] Those skilled in the art should understand that the above descriptions are merely several specific embodiments of the present invention, and not all embodiments. It should be noted that many modifications and improvements can be made by those skilled in the art, and all modifications or improvements not exceeding the scope of the claims should be considered within the protection scope of the present invention.

Claims

1. A method for preparing a TPE waterborne polyurethane biomimetic robotic skin material, characterized in that, Includes the following steps: S1. Lay the heating film flat and coat it with a layer of molten thermoplastic elastomer, TPE, with a coating thickness of 1-3cm. Alternatively, a molten thermoplastic elastomer, TPE, can be prepared first, and then the molten TPE can be foamed by 1-3 times through a foaming process to obtain foamed TPE. The heating film can be laid flat, and a layer of foamed TPE can be coated on the heating film with a coating thickness of 1-3 cm. The thermoplastic elastomer (TPE) is filled with filler oil. The mass ratio of the raw material SEBS to the filler oil in preparing the TPE is 1 / 12-1 / 8, and the density of the TPE is 0.82-0.88 g / cm³. 3 The melt flow index is 120-200 g / 10 min; S2. Then, a layer of water-based polyurethane synthetic leather with a thickness of 2-5mm is coated on the molten TPE or foamed TPE, and after hot pressing and cooling, the composite material is obtained. S3. A layer of surface treatment agent is sprayed onto the surface of the water-based polyurethane synthetic leather in the composite material and dried at 100-120℃ to obtain the biomimetic robot skin material.

2. The method for preparing the TPE waterborne polyurethane biomimetic robot skin material according to claim 1, characterized in that, The waterborne polyurethane resin in the waterborne polyurethane synthetic leather has a foaming ratio of 2-4 times, a tensile strength of 20-40 MPa, a modulus of 0.8-1.5 MPa, and an elongation at break of 500%-900%.

3. The method for preparing the TPE waterborne polyurethane biomimetic robotic skin material according to claim 1 or 2, characterized in that, The waterborne polyurethane resin in the waterborne polyurethane synthetic leather is an easily foaming waterborne polyurethane resin or a waterborne polyurethane fabric resin.

4. The method for preparing the TPE waterborne polyurethane biomimetic robotic skin material according to claim 3, characterized in that, The waterborne polyurethane resin in the waterborne polyurethane synthetic leather is one of the resins KT650, KT750, and KT621 from Hefei Ketian Waterborne Technology Co., Ltd.

5. The method for preparing the TPE waterborne polyurethane biomimetic robotic skin material according to claim 3, characterized in that, The preparation method of the waterborne polyurethane synthetic leather is as follows: waterborne polyurethane resin is foamed to a ratio of 2-4, then coated onto four-way stretch fabric, and then dried and shaped at a temperature of 70-90℃ to obtain waterborne polyurethane synthetic leather.

6. The method for preparing the TPE waterborne polyurethane biomimetic robot skin material according to claim 1, characterized in that, The heating film contains a fold-resistant copper wire nonwoven heating film system, and the surface treatment agent is a silicon-containing surface treatment agent.

7. The method for preparing the TPE waterborne polyurethane biomimetic robot skin material according to claim 1, characterized in that, The hot pressing in step S2 is performed at a temperature of 160-180℃, a pressure of 0.15Kpa-2Kpa, and a time of 5-30min.

8. The method for preparing the TPE waterborne polyurethane biomimetic robot skin material according to claim 1, characterized in that, The foaming process described in step S1 is mechanical foaming by adding a foaming agent. The foaming agent is an expandable microsphere foaming agent, and the addition ratio in the TPE material is 0.5-1.5 wt%, with a stirring rate of 2500-4000 r / min.

9. A TPE waterborne polyurethane biomimetic robot skin material prepared by the preparation method according to any one of claims 1-8.

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