Simulated silicone skin for robots

Abstract

The invention provides simulated organosilicon skin for a robot, the simulated organosilicon skin comprises a base cloth layer and an organosilicon layer arranged on the base cloth layer, the organosilicon layer comprises the following components in parts by mass: 90-110 parts of vinyl terminated PDMS, 1.2-1.5 parts of hydrogen-containing silicone oil, 0.5 part of a platinum catalyst, 8-10 parts of fumed silica, 5-8 parts of polyurethane microspheres, and 10-15 parts of low molecular weight PDMS. According to the simulation organic silicon skin for the robot, touch simulation, multifunctionality and environmental adaptability can be achieved at the same time.

Description

Technical Field

[0001] The present invention relates to the technical field of film materials, and in particular to a simulated organic silicon skin for a robot. Background Art

[0002] In the existing fields of materials science and bionics, artificial leather, as a functional material to replace natural skin, has formed a mature technical system. At present, artificial leather is mainly based on polyurethane (PU), polyvinyl chloride (PVC) and natural polymers (such as collagen, cellulose), and is prepared by coating, cross-linking or composite processes. For example, polyurethane-based artificial leather is widely used in robot surfaces, simulation models and medical protective gear due to its good flexibility and wear resistance; natural polymer-based artificial leather is often used in wound repair and skin transplantation due to its biocompatibility advantages. In addition, some artificial leathers achieve texture simulation or specific functions (such as antibacterial and breathable) through micro-nanostructure design or surface coating treatment to meet the needs of different scenarios.

[0003] However, existing artificial leather technology still has significant limitations. On the one hand, the touch of materials such as polyurethane and PVC is different from that of real skin, and their surface hardness and elastic recovery performance are difficult to accurately control, resulting in stiff tactile feedback, especially in robot-human interaction scenarios, and unable to provide a natural contact experience; on the other hand, existing materials are insufficient in balancing durability and functionality. For example, natural polymer materials have poor stain and scratch resistance, while synthetic materials are prone to aging and deformation in extreme environments (such as high temperature and high humidity), making it difficult to meet the comprehensive requirements of material performance in complex application scenarios. At the same time, the surface texture of existing artificial leather is mostly fixed in form, lacks dynamic designability, and cannot meet personalized customization needs. Therefore, there is an urgent need to develop a new type of artificial leather material that takes into account tactile simulation, multifunctionality and environmental adaptability. Summary of the Invention

[0004] The present invention aims to solve the above problems and provides a simulated silicone skin for a robot.

[0005] To achieve the above objectives, the present invention provides a simulated silicone skin for a robot, comprising a base fabric layer and a silicone layer disposed on the base fabric layer. The silicone layer comprises, by mass, 90-110 parts of vinyl-terminated PDM, 1.2-1.5 parts of hydrogenated silicone oil, 0.5 parts of a platinum catalyst, 8-10 parts of fumed silica, 5-8 parts of polyurethane microspheres, 10-15 parts of low-molecular-weight PDMS, 3 parts of hydroxyapatite nanoparticles, and 2 parts of nano-titanium dioxide for enhancing stain resistance.

[0006] In the simulated silicone skin for a robot involved in the present invention, optionally, the hardness of the silicone layer is such that the surface of the silicone layer has textures of simulated leather.

[0007] In the simulated organic silicone skin for robots involved in the present invention, optionally, the Si—H content in the hydrogenated silicone oil is 1.6%.

[0008] In the simulated organic silicone skin for robots involved in the present invention, optionally, the isopropyl alcohol solution content in the platinum catalyst is 2%.

[0009] In the simulated silicone skin for robots involved in the present invention, optionally, the base layer is made of.

[0010] In the simulated silicone skin for robots involved in the present invention, optionally, the particle size of the polyurethane microspheres is 6-10 μm.

[0011] In the simulated silicone skin for robots involved in the present invention, optionally, the viscosity of the vinyl-terminated PDM is 10,000 cSt.

[0012] In the simulated organic silicon skin for robots involved in the present invention, optionally, the components of the organic silicon layer also include ultraviolet absorbers and antioxidants.

[0013] In the simulated organic silicon skin for robots involved in the present invention, optionally, a tactile layer is provided on a side of the organic silicon layer away from the base fabric layer.

[0014] According to the present invention, a simulated silicone skin for a robot that takes into account tactile simulation, multifunctionality, and environmental adaptability can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings in the description are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0016] Figure 1 It is a schematic structural diagram of the simulated organic silicon skin for robots of the present invention. DETAILED DESCRIPTION

[0017] To make the purpose, technical solutions, and advantages of the invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0018] The hardness of silicone is essentially determined by the crosslinking density, molecular chain flexibility and the interaction between fillers.

[0019] In some embodiments, the hardness of the highly cross-linked silicone rubber can reach Shore A 80 or higher.

[0020] In some embodiments, the polydimethylsiloxane (PDMS) segment has excellent flexibility due to the low steric hindrance of the methyl group.

[0021] In some embodiments, fumed silica can significantly increase the hardness of silicone rubber.

[0022] It is understandable that the feel of human skin corresponds to a Shore A hardness of approximately 10-30, and precise control is required to ensure that the hardness of silicone reaches this range.

[0023] In some embodiments, groups other than methyl groups can be introduced into the PDMS backbone.

[0024] For example, embedding ethyl or phenyl groups (e.g., polymethylphenylsiloxane) into the PDMS backbone can increase the steric hindrance of the side groups, reducing the chain segment mobility, thereby increasing the modulus while maintaining flexibility (but the ratio must be controlled; too high a phenyl content will increase the hardness). This allows the flexibility of the backbone to be adjusted.

[0025] In some embodiments, the silicone rubber with a phenyl content of 5-10% can have a Shore A hardness of 20-30 and a skin-like warm touch.

[0026] In some embodiments, the molecular weight of the polymer is increased (e.g., PDMS with a viscosity ≥ 5000 cSt) to enhance the elasticity by increasing the intermolecular entanglement force, thereby avoiding the material being too soft and causing a "collapse feeling."

[0027] In some embodiments, hydroxyl-terminated PDMS (OH-PDMS) can be cross-linked with alkoxy-containing silanes (such as tetraethyl orthosilicate), and the cross-linking density can be adjusted by controlling the hydroxyl / alkoxy molar ratio.

[0028] In some embodiments, when the ratio of hydroxyl group to alkoxy group is 1:1.2, the crosslinking density is moderate and the hardness can reach Shore A 25-30.

[0029] In some embodiments, vinyl-containing PDMS can be cross-linked with hydrogen-containing silicone oil under platinum catalysis, and the cross-linking point density can be controlled by adjusting the Si-H bond content of the hydrogen-containing silicone oil.

[0030] In some embodiments, when Si—H:vinyl=1:1.1, the cross-linked network is uniform and the hardness can be stabilized at Shore A5-25.

[0031] In some embodiments, low-durometer elastomeric particles may be incorporated into the silicone.

[0032] For example, adding polyurethane (PU) microspheres (particle size 5-10 μm, content 5-10%) and dispersing them in the silicone matrix through an "island structure" can reduce the overall modulus while giving it a skin-like delicate touch.

[0033] In some embodiments, a plasticizer may be added to the silicone.

[0034] For example, adding low-molecular-weight PDMS (viscosity 100-500 cSt) as a plasticizer at a dosage of 10-20% can significantly reduce hardness (by 5-10 degrees Shore A hardness), but be aware that excessive amounts can cause the material to oil (migration issues).

[0035] In some embodiments, functional fillers can be added to silicone to mimic skin properties.

[0036] For example, an appropriate amount of nano-silica (white carbon black) may be added.

[0037] In some embodiments, fumed silica (specific surface area 200-300 m 2 The amount of siloxane (amount / g) can be controlled at 5-10%. Through the interaction of hydrogen bonds with the siloxane chain, it can enhance the "support" of the material (similar to the elasticity of the fat layer under the skin) while avoiding excessive hardness increase (hardness increases significantly when the amount is greater than 15%).

[0038] In some embodiments, biomimetic structural fillers may be added to silicone.

[0039] For example, loaded hydroxyapatite (HA) nanoparticles (content 3-5%) can be added, and the surface hydroxyl groups form hydrogen bonds with silicone, which not only adjusts the hardness but also gives the material skin-like hydrophilicity (contact angle <60°), thereby improving the realism of the touch.

[0040] In some embodiments, the difference in hardness between the surface and the interior can be achieved by controlling the crosslinker distribution.

[0041] In some embodiments, the surface layer can use a low cross-linking density formula (such as a 10% reduction in the amount of hydrogen silicone oil used), and the interior uses a medium cross-linking density to form a "soft outside and elastic inside" structure to simulate the mechanical stratification of the skin epidermis and dermis (epidermis Shore A hardness 15-20, dermis 25-30).

[0042] In some embodiments, silicone can be cured at low temperature and fully cured at medium temperature.

[0043] For example, curing at 40°C for 2 hours (initial cross-linking, molecular chains retain mobility), and then heating to 80°C for 1 hour to fully cross-link, can reduce internal stress and make the hardness distribution more uniform (deviation ≤±2 Shore A).

[0044] In some embodiments, the prepared silicone surface may be plasma treated.

[0045] For example, oxygen plasma (power 50-100W, processing time 30 seconds) is used to etch the surface, introduce hydroxyl groups, reduce the surface energy (from about 24mN / m to 18mN / m), and slightly swell the surface layer, reducing the hardness by 5-8 degrees, simulating the moist and delicate feeling of the skin.

[0046] The following are the key performance test and evaluation data of the silicone in this application.

[0047] Hardness test: Shore A hardness tester (indenter diameter 5 mm) was used, test conditions were 23°C × 50% RH, pressing time was 5 seconds, and the average value of 3 points was taken.

[0048] Hand feel simulation evaluation:

[0049] Subjective evaluation: Invite 10 subjects to touch the sample and score it based on "softness", "elastic recovery speed" and "stickiness" (out of 10 points). The softness must be ≥ 8 points and the elastic recovery time must be < 0.5 seconds.

[0050] Objective testing: Use a tactile sensor (such as a pressure-deformation curve meter) to simulate the force-displacement curve when a finger presses, and compare it with real skin data (10-30% deformation at a pressure of 1-5N).

[0051] In some embodiments, a typical formula example of silicone (taking addition-type silicone rubber as an example) is as follows:

[0052]

[0053]

[0054] In some embodiments, to improve biocompatibility, food-grade or medical-grade raw materials (such as FDA-certified silicones) may be selected to avoid allergies caused by migration of additives.

[0055] In some embodiments, to improve aging resistance, 0.5-1% of a UV absorber (such as benzophenone) and an antioxidant (such as an organic tin compound) can be added to prevent hardness changes due to breakage of the cross-linked network after long-term use (hardness fluctuation ≤±5% after 1000 hours of aging).

[0056] Through the above-mentioned molecular design, formula optimization and process control, the hardness of silicone can be precisely controlled within the Shore A10-30 range, while meeting the elasticity, skin-friendliness and weather resistance requirements required for skin feel.

[0057] The following details an example of preparing artificial leather with different properties by adjusting the ingredients in the silicone.

[0058] Example 1: Highly elastic skin-friendly silicone artificial leather

[0059] In some embodiments, the raw material formula of the highly elastic skin-friendly silicone artificial leather (in parts by mass) may include:

[0060] Vinyl-terminated PDMS (viscosity 15000 cSt), 100 parts; hydrogenated silicone oil (Si-H content 1.5%), 1.3 parts; platinum catalyst (2% isopropanol solution), 0.6 parts; fumed silica (specific surface area 250 m 2 / g), 7 parts; polyurethane microspheres (particle size 8 μm), 6 parts; low molecular weight PDMS (viscosity 300 cSt), 12 parts; hydroxyapatite nanoparticles, 4 parts.

[0061] In some embodiments, the preparation process of the highly elastic skin-friendly silicone artificial leather may include:

[0062] Step 1: Add vinyl-terminated PDMS and low molecular weight PDMS into a reactor, stir evenly, and heat to 60°C;

[0063] Step 2: Add fumed silica, polyurethane microspheres, and hydroxyapatite nanoparticles in sequence, and stir at high speed for 30 minutes to evenly disperse the fillers;

[0064] Step 3: Cool to room temperature, add hydrogenated silicone oil and platinum catalyst, and stir for 10 minutes;

[0065] Step 4: Pour the mixed material into the mold, pre-cure it at 40°C for 2 hours, and then heat it to 80°C for 1.5 hours;

[0066] Step 5: After curing, take out the film and treat the surface using oxygen plasma (power 80 W, treatment time 35 seconds).

[0067] In some embodiments, the performance test results of the highly elastic skin-friendly silicone artificial leather are as follows:

[0068]

[0069] Example 2: Wear-resistant and stain-resistant silicone artificial leather

[0070] In some embodiments, the formula of the wear-resistant and stain-resistant organic silicone artificial leather raw materials (by mass) is as follows:

[0071] Vinyl-terminated PDMS (viscosity 12000 cSt), 100 parts; hydrogenated silicone oil (Si-H content 1.6%), 1.4 parts; platinum catalyst (2% isopropanol solution), 0.5 parts; fumed silica (specific surface area 300 m 2 / g), 9 parts; polyurethane microspheres (particle size 6 μm), 5 parts; low molecular weight PDMS (viscosity 400 cSt), 10 parts; hydroxyapatite nanoparticles, 3 parts; nano titanium dioxide (for enhancing stain resistance), 2 parts.

[0072] In some embodiments, the process for preparing wear-resistant and stain-resistant silicone artificial leather may include:

[0073] Step 1, vinyl-terminated PDMS, low molecular weight PDMS, fumed silica, polyurethane microspheres, hydroxyapatite nanoparticles, and nano-titanium dioxide are added to a reactor in order, and stirred and dispersed at 70° C. for 40 minutes;

[0074] Step 2: After cooling to room temperature, add hydrogenated silicone oil and platinum catalyst and stir evenly;

[0075] Step 3: inject into the mold, pre-cure at 45°C for 2.5 hours, and then fully cure at 90°C for 1.2 hours;

[0076] Step 4: After taking it out, perform surface polishing to improve surface flatness.

[0077] In some embodiments, the test results of the wear-resistant and stain-resistant silicone artificial leather are as follows:

[0078] Test items Test results Shore A hardness 26 Abrasion times (Taber abrasion test) 500 times without noticeable wear contact angle 78°, water droplets can roll off the surface easily Temperature range Stable performance from -40℃ to 200℃

[0079] Example 3: Low-cost and rapid preparation of silicone artificial leather

[0080] In some embodiments, the raw material formula (by mass) for low-cost, rapidly prepared silicone artificial leather may include: vinyl-terminated PDMS (viscosity 10,000 cSt), 100 parts; hydrogenated silicone oil (Si-H content 1.4%), 1.2 parts; platinum catalyst (2% isopropanol solution), 0.4 parts; fumed silica (specific surface area 200 m2 / g), 6 parts; polyurethane microspheres (particle size 10 μm), 4 parts; low molecular weight PDMS (viscosity 200 cSt), 8 parts.

[0081] In some embodiments, a process for preparing low-cost, fast-preparation silicone artificial leather may include:

[0082] Step 1, vinyl terminated PDMS and low molecular weight PDMS were mixed and stirred at 50°C until uniform;

[0083] Step 2, adding fumed silica and polyurethane microspheres and stirring for 20 minutes;

[0084] Step 3, add hydrogenated silicone oil and platinum catalyst, stir rapidly for 5 minutes, and pour into the mold;

[0085] Step 4: Use microwave curing at a power of 300 W for 3 minutes, and then let it stand at room temperature for 2 hours.

[0086] In some embodiments, the performance test results of the low-cost, rapidly prepared silicone artificial leather are as follows:

[0087]

[0088] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein, and these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A simulated silicone skin for a robot, characterized in that: The invention comprises a base fabric layer and an organic silicon layer arranged on the base fabric layer. The components of the organic silicon layer include, by mass, 90-110 parts of vinyl-terminated PDMS, 1.2-1.5 parts of hydrogenated silicone oil, 0.5 parts of platinum catalyst, 8-10 parts of fumed silica, 5-8 parts of polyurethane microspheres, 10-15 parts of low-molecular-weight PDMS, 3 parts of hydroxyapatite nanoparticles, and 2 parts of nano-titanium dioxide for enhancing stain resistance.

2. The artificial silicone skin for a robot according to claim 1, characterized in that: The hardness of the organic silicon layer is Shore A10-30, and the surface of the organic silicon layer has leather-like texture.

3. The artificial silicone skin for a robot according to claim 1, characterized in that: The Si—H content in the hydrogen-containing silicone oil is 1.6%.

4. The artificial silicone skin for a robot according to claim 1, characterized in that: The content of the isopropanol solution in the platinum catalyst is 2%.

5. The artificial silicone skin for a robot according to claim 1, characterized in that: The base layer is made of two-sided stretch fabric or four-sided stretch fabric.

6. The artificial silicone skin for a robot according to claim 1, characterized in that: The particle size of the polyurethane microspheres is 6-10 μm.

7. The artificial silicone skin for a robot according to claim 6, characterized in that: The viscosity of the vinyl terminated PDMS is 10000 cSt.

8. The artificial silicone skin for a robot according to claim 1, characterized in that: The components of the organic silicon layer further include an ultraviolet absorber and an antioxidant.

9. The artificial silicone skin for a robot according to claim 1, characterized in that: A hand-feeling layer is provided on a side of the organic silicon layer away from the base fabric layer.

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