Robot simulation skin and preparation method thereof

Abstract

The invention belongs to the technical field of simulation skin, and particularly relates to robot simulation skin and a preparation method thereof. Raw materials: an elastomer matrix; a base oil agent; a polyolefin; a compatilizer; rubber; a temperature-sensitive auxiliary agent; a photosensitive auxiliary agent; conductive particles; an antioxidant; and other auxiliary agents. The preparation method comprises the following steps: quickly stirring, rubbing and heating the elastomer matrix, adding the base oil agent, filling oil, premixing with polyolefin, putting into an extruder, adding the rubber and the compatilizer, extruding, granulating, adding the temperature-sensitive additive, the light-sensitive additive, the conductive particles and the antioxidant under a dark condition, and continuously stirring; adding other auxiliary agents, and uniformly dispersing; the mixed composite material is subjected to calendaring molding or injection molding or tape casting, and the robot simulation skin is obtained. The skin prepared by the invention has basic mechanical properties and environmental response capability, and can give consideration to both softness and durability.

Description

Technical Field

[0001] This invention belongs to the field of simulated skin technology, specifically relating to robotic simulated skin and its preparation method. Background Technology

[0002] With the rapid development of service robots, smart wearable devices, and human-computer interaction systems, biomimetic materials technology has become an important foundation for supporting the advancement of artificial intelligence towards human-like features. Among them, robotic simulated skin, as a key interface for achieving tactile recognition, facial expression interaction, and human-computer integration, has become a research hotspot due to its material system design, functional integration, and flexible fabrication technology.

[0003] Traditional robot skin materials have certain problems: ordinary silicone skin only has basic mechanical properties and lacks the ability to respond to the environment; low-hardness materials often cannot balance softness and durability. Summary of the Invention

[0004] In view of this, the present invention aims to propose a robotic simulated skin and a method for its preparation.

[0005] To achieve the above objectives, the technical solution of the present invention is implemented as follows: Firstly, the robotic simulated skin comprises the following raw materials by weight: 35-85 parts elastomer matrix; 35-1000 parts base oil; 2-8 parts polyolefin; 2-6 parts compatibilizer; 4-10 parts rubber; 0.5-3 parts temperature-sensitive additive; 0.2-1.5 parts photosensitizing additive; 0.5-3 parts conductive particles; 0.1-0.6 parts antioxidant; and 0.5-2 parts other additives.

[0006] Furthermore, the elastomer matrix includes one or more of SEBS, SBS, and SEPS; the polyolefin includes PP.

[0007] Furthermore, the base oil includes one or more of white oil and naphthenic oil; the conductive particles include one or more of carbon black coated silver, carbon nanotubes, graphene, and conductive mica powder.

[0008] Furthermore, the rubber includes one or more of liquid silicone rubber, liquid styrene-butadiene rubber, and liquid nitrile rubber; other additives include one or more of silica and resin microspheres.

[0009] Furthermore, the compatibilizer includes one or more of the following: POE-grafted compatibilizer, SEBS-grafted compatibilizer, and polystyrene-grafted compatibilizer.

[0010] Furthermore, the preparation method of the temperature-sensitive additive includes the following steps: The dye precursor and color developer are added to the solvent and mixed evenly to obtain the oil phase; gelatin and gum arabic are dissolved in deionized water to obtain the aqueous phase; the oil phase is added dropwise to the aqueous phase and emulsified to obtain an emulsion; the emulsion is cooled, glutaraldehyde solution is added dropwise, and crosslinking is carried out by continuous stirring to obtain microcapsules; the microcapsules are cooled, filtered, washed, and dried to obtain the temperature-sensitive auxiliary agent.

[0011] Furthermore, the dye precursor includes crystal violet lactone; the color developer includes bisphenol AF and zinc stearate; and the solvent includes 1-decyl alcohol.

[0012] Furthermore, the preparation method of the photosensitizing agent includes the following steps: Acetone and ethanol were prepared into a solution, and the photochromic material and antioxidant were dissolved in the solution. The mixture was stirred in the dark, and TEOS was added and stirred until homogeneous. The mixture was then added to a PVA solution, and the pH was adjusted to acidic under an ice bath. The reaction was continued with stirring. After the reaction, the mixture was filtered and dried to obtain the photosensitive additive.

[0013] Furthermore, photochromic materials include spiropyran.

[0014] Secondly, the aforementioned method for preparing robotic simulated skin includes the following steps: The elastomer matrix is ​​rapidly heated by frictional stirring, then a base oil is added and the mixture is filled with oil. Rubber is then added, and the mixture is premixed with polyolefin and compatibilizer before being fed into an extruder for extrusion and granulation. Under light-protected conditions, temperature-sensitive additives, light-sensitive additives, conductive particles, and antioxidants are added, and stirring continues. Other additives are added and dispersed evenly. The mixed composite material is then calendered, injection molded, or cast to obtain robotic simulated skin.

[0015] Compared with the prior art, the present invention has the following advantages: 1. A flexible network structure was constructed by synergistic blending of three elastomer matrices: SEBS, SBS, and SEPS. SEBS provides basic softness, SBS enhances resilience, and SEPS strengthens toughness and thermal stability. This results in a material with low hardness, high elongation at break, and high resilience, achieving a touch similar to human skin.

[0016] 2. Introducing conductive fillers into the elastomer matrix not only creates a conductive network within the material, providing a material basis for "electronic skin" applications, but also ensures stable dispersion of the conductive fillers within the elastomer system through the use of a grafted compatibilizer, forming a continuous conductive path. This also enhances interfacial bonding and avoids the problems of conductive particle sedimentation and oil seepage found in traditional materials.

[0017] 3. This invention constructs a dual-response color-changing system using self-made temperature-sensitive and light-sensitive additives, respectively. This system can achieve color changes within a certain temperature range or under varying light conditions, exhibiting reversibility and good repeatability, thus expanding the application of simulated skin in the field of visual interaction. Furthermore, both the temperature-sensitive and light-sensitive additives utilize microcapsule or nano-encapsulation structures, ensuring long-term stability of the entire system without leakage or precipitation.

[0018] 4. The base oil can form a micro-dispersed structure in the matrix, and work synergistically with the liquid rubber to adjust the softness of the material, reduce the elastic modulus while maintaining tensile and resilience properties; the interfacial regulation effect between the compatibilizer and the liquid rubber further enhances the stability of the system. Detailed Implementation

[0019] The preferred embodiments of the present invention are described in detail below. However, the present invention is not limited to the specific details in the following embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0020] It should also be noted that the various specific technical features described in the following specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0021] Unless otherwise specified, the equipment and materials used in the embodiments can be readily obtained from commercial companies.

[0022] Robotic simulated skin contains the following raw materials in parts by weight: Elastomer matrix: one or more of SEBS, SBS, and SEPS, 35-85 parts; Base oil: white oil or naphthenic oil, 35-1000 parts; white oil can be No. 36, No. 50 or No. 100 white oil; Polyolefin: PP, 2-8 parts; Compatibilizer: 2-6 parts of compatibilizer grafted with POE, SEBS, or polystyrene; Rubber: Liquid silicone rubber, liquid styrene-butadiene rubber, or liquid nitrile rubber, 4-10 parts; Temperature-sensitive additive: 0.5-3 parts; Photosensitizing agent: 0.2-1.5 parts; Conductive particles: one or more of carbon black coated silver, carbon nanotubes, graphene, and conductive mica powder, 0.5-3 parts; Antioxidant: 0.1-0.6 parts; Other additives: one or more of silica and resin microspheres, 0.5-2 parts.

[0023] Based on the above-mentioned raw materials, a method for preparing robotic simulated skin is provided, and the specific steps are as follows: Step 1: The elastomer matrix is ​​rapidly heated by friction and stirring. The base oil is added and the mixture is filled with oil. Then, rubber is added and premixed with polyolefin and compatibilizer. The mixture is then fed into a twin-screw extruder and extruded at 170-190℃. Granulation is performed, requiring the twin-screw length-to-diameter ratio to be no less than 52:1, to obtain the mixture.

[0024] Step 2: Under light-protected conditions, add temperature-sensitive additives, light-sensitive additives, conductive particles, and antioxidants to the mixture, and continue stirring for 10 minutes; add other additives and disperse evenly.

[0025] Step 3: Inject the mixed composite material into a mold, with the thickness controlled between 0.5-3mm, to obtain the robot's simulated skin.

[0026] Additionally, if needed, low-temperature embossing or biomimetic molding can be used on the material surface to create a texture that mimics human skin.

[0027] Among them, the parameters for injection molding are: Mold temperature: 30-60℃; Barrel temperature: front section: 160-170℃; middle section: 170-180℃; rear section: 180-190℃; Injection pressure: 40-80 MPa; Pressure holding time: 5-15 seconds; Cooldown time: 10-30 seconds.

[0028] Based on the above-described method for preparing robotic simulated skin, and referring to Table 1, Examples 1-6 and Comparative Examples 1-4 are implemented.

[0029] Table 1

[0030] The specific raw material information in Table 1 is as follows: SEBS: Sinopec Baling YH-602T.

[0031] SBS: PetroChina Dushanzi T6302.

[0032] SEPS: Kuraray Septon 2063.

[0033] White oil: 50# white oil (50# white oil).

[0034] Compatibilizer: Grafted SEBS, purchased from Kraton's FG1901.

[0035] The liquid rubber is liquid silicone rubber, Shin-Etsu's KE-1950-50.

[0036] Temperature-sensitive additive: The temperature-sensitive additive prepared in Example 8.

[0037] Photosensitive additive: The photosensitive additive prepared in Example 9.

[0038] Conductive filler: Multi-walled carbon nanotubes, Nanocyl NC7000 TM .

[0039] Other additives include silica and resin microspheres. The silica is AEROSIL® 200 from Evonik. The resin microspheres are Polybead® Microspheres 5μm from Polysciences Inc.

[0040] The antioxidant is antioxidant 1010.

[0041] Example 7 The specific steps for preparing temperature-sensitive additives are as follows: 1. Selecting raw materials: Dye precursor: Crystal violet lactone (CVL) Color developer: Bisphenol AF, zinc stearate Solvent: 1-Decanol 2. Add 2.5g of dye precursor and 8g of color developer (6g of bisphenol AF and 2g of zinc stearate) to 3g of solvent, and disperse by ultrasonication at 40kHz for 10min at 60℃. Mix well to obtain the oil phase. 3. Dissolve 12g of gelatin and 12g of gum arabic in 200g of deionized water to obtain the aqueous phase.

[0042] 4. Slowly add the oil phase to the aqueous phase and emulsify at 1000-1500 rpm for 20 minutes to obtain an emulsion. Then, cool the emulsion to 35-40℃, add 3.5g of 25% glutaraldehyde solution, and stir continuously for 2 hours to crosslink the emulsion to obtain microcapsules. Cool, filter, wash, and dry to obtain the temperature-sensitive additive.

[0043] It should be noted that in the above technical solutions, The oil phase is first encapsulated by the aqueous phase. After the addition of glutaraldehyde, the glutaraldehyde completes the colloidal cross-linking reaction in the aqueous phase to form microcapsules.

[0044] In the oil phase, bisphenol AF and CVL form a hydrogen bond complex structure, and zinc stearate regulates the spatial configuration and polar environment of the hydrogen bond network, which together determine the color change threshold and color development rate.

[0045] The oil phase core is hydrophobic and has strong compatibility with base oils (white oil or naphthenic oil).

[0046] When temperature-sensitive additives are distributed in the microscopic continuous phase of the elastomer matrix, they can trigger a color change reaction under deformation stress or local heat accumulation. Reversible color development / decolorization conversion can be achieved in the temperature range of 30-40℃. When the temperature rises above the stability threshold of the complex bond between bisphenol AF and CVL, the hydrogen bond breaks, the CVL structure rearranges, and the color changes from colorless to colored. When the temperature drops, bisphenol AF reforms the complex, restores the original state, and the color fades.

[0047] Example 8 The specific steps for preparing photosensitizing additives are as follows: 1. Selecting raw materials: Photochromic material: Spiropyran Antioxidant: Antioxidant 264 TEOS: Ethyl silicate PVA: Polyvinyl alcohol 2. Prepare a solution by mixing acetone and ethanol in a 1:1 mass ratio. Dissolve 2g of photochromic material and 0.3g of antioxidant in 30ml of the solution. Stir in the dark, add 10g of TEOS and stir until homogeneous. Then add the mixture to 100g of 4wt% PVA solution and adjust the pH to acidic under ice bath conditions. Continue stirring at 40℃ for 2 hours. After the reaction, filter and dry to obtain nanoparticles, i.e., the photosensitive additive.

[0048] It should be noted that in the above technical solutions, Spiropyran is a photosensitive material that can undergo a reversible ring-opening and ring-closing reaction under ultraviolet or visible light irradiation, resulting in a color change.

[0049] TEOS undergoes hydrolysis and condensation in the presence of ammonia to form a silica framework. This framework is then used to form a nanostructure through a sol-gel process, achieving physical encapsulation of spiropyran and resulting in more stable overall material chemical properties.

[0050] Examples 1-6 and Comparative Examples 1-4 were tested. Comparative Example 2 did not contain temperature-sensitive or photosensitizing additives, so the temperature change response time and photosensitivity response time were not tested. The results are shown in Table 2.

[0051] Table 2

[0052] Detection: Shore A hardness: GB / T 531.1-2008; Tensile strength: GB / T 528-2009; Elongation at break: GB / T 528-2009; Resilience (springback rate): The sample is compressed to 30% height, held for 30 seconds, then unloaded, and the springback height is measured after 30 seconds. Temperature change response threshold: Place the sample on a gradually heated stage (from 25℃ to 50℃) and record the color development onset temperature and the time to complete color change. Photosensitivity response time: The sample is placed in the dark, and then the UV lamp is turned on to irradiate the sample. The time required from irradiation to obvious color change is recorded.

[0053] analyze: The hardness of all embodiments is controlled between 0 and 15A, with a high resilience, giving the simulated skin a soft touch.

[0054] Comparative Example 4 uses a single SEBS, while the examples use SEBS, SBS, and SEPS, which work synergistically to reduce hardness.

[0055] SEBS provides a soft touch, SEPS provides resilient support, and SBS provides resilience. By adjusting the three in different proportions, a low hardness, high elongation, and high resilience effect can be achieved.

[0056] Base oils can plasticize, reduce modulus, and improve softness. White oil is used in the examples; it forms a micro-dispersion structure in the polymer phase, which facilitates interphase slippage and imparts a simulated skin-like feel to the material with low hardness and high deformation.

[0057] The compatibilizer has a polar and non-polar partitioned grafted structure, which can improve the interfacial compatibility of SEBS with polar and non-polar components such as PP and liquid rubber.

[0058] Temperature-sensitive additives can give materials the ability to change color with temperature, similar to the reaction of body temperature. This allows simulated skin to change from colorless to colored, or colored to colorless, in response to changes in "body temperature".

[0059] Photosensitive additives can endow materials with reversible photochromic properties, allowing simulated skin to change from colorless to colored, or from colored to colorless, as the light changes.

[0060] Regarding conductive fillers, they not only meet the requirements of basic "electronic skin" but can also serve as reinforcing fillers. Comparative Example 1, without the addition of conductive fillers, showed decreased tensile strength and elongation at break compared to the previous example.

[0061] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. Robotic simulated skin, characterized in that, The raw materials include the following parts by weight: 35-85 parts elastomer matrix; 35-1000 parts base oil; 2-8 parts polyolefin; 2-6 parts compatibilizer; 4-10 parts rubber; 0.5-3 parts temperature-sensitive additive; 0.2-1.5 parts photosensitizing additive; 0.5-3 parts conductive particles; and 0.1-0.6 parts antioxidant. Other additives: 0.5-2 parts.

2. The robotic simulated skin according to claim 1, characterized in that, The elastomer matrix includes one or more of SEBS, SBS, and SEPS; the polyolefin includes PP.

3. The robotic simulated skin according to claim 1, characterized in that, The base oil includes one or more of white oil and naphthenic oil; the conductive particles include one or more of carbon black coated silver, carbon nanotubes, graphene, and conductive mica powder.

4. The robotic simulated skin according to claim 1, characterized in that, The rubber includes one or more of liquid silicone rubber, liquid styrene-butadiene rubber, and liquid nitrile rubber; other additives include one or more of silica and resin microspheres.

5. The robotic simulated skin according to claim 1, characterized in that, The compatibilizer includes one or more of the following: POE graft compatibilizer, SEBS graft compatibilizer, and polystyrene graft compatibilizer.

6. The robotic simulated skin according to claim 1, characterized in that, The preparation method of the temperature-sensitive additive includes the following steps: The dye precursor and color developer are added to the solvent and mixed evenly to obtain the oil phase; gelatin and gum arabic are dissolved in deionized water to obtain the aqueous phase; the oil phase is added dropwise to the aqueous phase and emulsified to obtain an emulsion; the emulsion is cooled, glutaraldehyde solution is added dropwise, and crosslinking is carried out by continuous stirring to obtain microcapsules; the microcapsules are cooled, filtered, washed, and dried to obtain the temperature-sensitive auxiliary agent.

7. The robotic simulated skin according to claim 6, characterized in that, The dye precursors include crystal violet lactone; the color developers include bisphenol AF and zinc stearate; and the solvent includes 1-decyl alcohol.

8. The robotic simulated skin according to claim 1, characterized in that, The preparation method of the photosensitizing agent includes the following steps: Acetone and ethanol were prepared into a solution, and the photochromic material and antioxidant were dissolved in the solution. The mixture was stirred in the dark, and TEOS was added and stirred until homogeneous. The mixture was then added to a PVA solution, and the pH was adjusted to acidic under an ice bath. The reaction was continued with stirring. After the reaction, the mixture was filtered and dried to obtain the photosensitive additive.

9. The robotic simulated skin according to claim 8, characterized in that, Photochromic materials include spiropyran.

10. The method for preparing robotic simulated skin according to any one of claims 1-9, characterized in that, Includes the following steps: The elastomer matrix is ​​rapidly heated by frictional stirring, then a base oil is added and the mixture is filled with oil. Rubber is then added, and the mixture is premixed with polyolefin and compatibilizer before being fed into an extruder for extrusion and granulation. Under light-protected conditions, temperature-sensitive additives, light-sensitive additives, conductive particles, and antioxidants are added, and stirring continues. Other additives are added and dispersed evenly. The mixed composite material is then calendered, injection molded, or cast to obtain robotic simulated skin.

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