A flexible body interconnection structure based on porous structure and forming method

Abstract

The present invention belongs to the technical field related to flexible materials, and discloses a flexible body interconnection structure and molding method based on a porous structure. The structure includes a first flexible body and a second flexible body, wherein the first flexible body is provided with a three-dimensional mesh porous structure, and the second flexible body is connected to the first flexible body by filling the porous structure of the first flexible body, thereby forming a flexible body interconnection structure. The present invention also discloses a molding method for the above-mentioned flexible body structure. Through the present invention, the connection is made using the flexible body body material, without the introduction of adhesives, and the use scenario does not need to be limited to adhesive materials. The porous structure interwoven after the silicone rubber material is cured is connected to form a reliable connection.

Description

Technical Field

[0001] The present invention belongs to the technical field related to flexible materials, and more specifically, relates to a flexible body interconnection structure based on a porous structure and a molding method. Background Art

[0002] Soft robots, with their flexibility and adaptability, are gaining increasing attention in fields such as healthcare, education, services, rescue, exploration, detection, and wearable devices, demonstrating tremendous potential for development. As the structure and functionality of soft robotic systems become increasingly complex, modular design is becoming a trend, and connecting different modules has become a key technology for soft robotics.

[0003] Mechanical connections are widely used in soft robotic modules, but traditional mechanical connections mostly use rigid components, which can negatively impact the flexibility of soft robots. Consequently, new connection methods, such as flexible mechanical connections, flexible material adhesion, and flexible electrostatic and vacuum adsorption, have been proposed and applied to structural connections between soft robotic modules. Flexible material adhesion can be achieved using adhesives such as glue, hot-melt materials such as hot-melt bonding, and microstructures such as Velcro. It is a common method for connecting flexible components. However, both adhesives and hot-melt materials introduce a third material in addition to the two flexible components themselves, and their use is affected by factors such as temperature and humidity. Microstructures such as Velcro have limited connection strength, but these flexible connection methods also suffer from limited connection strength and limited application scenarios. Due to the widespread use of organic soft materials such as silicone rubber in flexible components such as soft robots, methods such as molding, 3D printing, and laser forming have been applied to the manufacturing of these components. These processing methods allow soft materials to be formed into complex structures.

[0004] Therefore, there is an urgent need for a structure and a molding method that can achieve flexible connection of flexible material pieces to solve the above problems. Summary of the Invention

[0005] In response to the above defects or improvement needs of the prior art, the present invention provides a flexible body interconnection structure and a forming method based on a porous structure to solve the problem of flexible connection of flexible bodies.

[0006] To achieve the above-mentioned purpose, according to one aspect of the present invention, a flexible body interconnection structure based on a porous structure is provided, which structure includes a first flexible body and a second flexible body, wherein the first flexible body is provided with a three-dimensional mesh porous structure, and the second flexible body is connected to the first flexible body by filling the porous structure of the first flexible body, thereby forming a flexible body interconnection structure.

[0007] Further preferably, the first flexible body material is platinum-catalyzed silicone rubber, polydimethylsiloxane, hydrogel or thermoplastic polyurethane (TPU)….

[0008] Further preferably, the second flexible body material is platinum-catalyzed silicone rubber, polydimethylsiloxane, or hydrogel.

[0009] Further preferably, electronic components may be provided in the first flexible body and the second flexible body.

[0010] Further preferably, the porosity of the three-dimensional network porous structure is 30% to 70%.

[0011] According to another aspect of the present invention, there is provided a method for forming the above-mentioned porous structure-based flexible interconnected structure, the method comprising the following steps:

[0012] S1 uses a casting method or a non-casting method to form a first flexible body having a three-dimensional mesh porous structure;

[0013] S2: pouring the material of the second flexible body into the first flexible body, and obtaining the required flexible interconnected structure after solidification.

[0014] Further preferably, the non-casting method adopts 3D printing, laser processing or self-growth molding.

[0015] Further preferably, the casting method adopts a crystal template method or a bracket method for casting and molding.

[0016] Further preferably, the crystal particles used in the crystal template method are a combination of one or more of water-soluble sugar, salt, and carbon tetrachloride-soluble iodine.

[0017] Further preferably, the material of the scaffold in the scaffold method includes high impact polystyrene, acrylonitrile-butadiene-styrene, polyvinyl butyrate or polyvinyl alcohol, and the main components of the corresponding dissolving solution are limonene, acetone, isopropyl alcohol and water respectively.

[0018] In general, the above technical solutions conceived by the present invention have the following beneficial effects compared with the prior art:

[0019] 1. This invention utilizes the flexible body's own material for connection, which has unlimited application scenarios. The three-dimensional porous network structure ensures good connection strength and body flexibility. Compared with conventional bonding, this method utilizes the flexible body's own material for connection, eliminating the need for adhesives and limiting application scenarios. The porous structure of the interwoven silicone rubber material after curing forms a reliable connection.

[0020] 2. The materials selected for the first flexible body of the present invention, including platinum-catalyzed silicone rubber, polydimethylsiloxane, and hydrogel materials, all have excellent flexibility and elasticity, can adapt to various shapes and surfaces, and are suitable for customized molding of diverse flexible substrates through casting. In addition, platinum-catalyzed silicone rubber also has good wear resistance, can withstand friction, and has excellent durability. Polydimethylsiloxane has an adjustable Young's modulus and excellent chemical stability, which makes the material suitable for a variety of application scenarios. Thermoplastic polyurethane has the characteristics of high elasticity and chemical corrosion resistance, and is suitable for use in 3D printing to form flexible substrates of different shapes and structures. The second flexible body is mainly molded by casting, and thermoplastic polyurethane is not considered for the time being.

[0021] 3. The total porosity of the three-dimensional network porous structure of the present invention is 30% to 70%. This porosity ensures the volume ratio and contact area of ​​the first flexible body and the second flexible body in the three-dimensional network connection structure, which is conducive to forming a stable flexible connection body. The actual internal pore distribution can also be set to a gradient distribution of varying degrees according to actual needs.

[0022] 4. The flexible body connection method provided by the present invention is not only applicable to the connection of two flexible bodies, but also to the spatial interconnection of multiple flexible bodies. The multi-step casting method not only divides a complex structure into multiple simple structures, but also reduces the difficulty of mold design and production.

[0023] 5. The flexible body interconnection structure based on the porous structure provided by the present invention is used in the field of soft robots. For soft robots that cannot be manufactured in an integrated manner and require multi-module assembly, it can achieve reliable connection between modules made of different soft materials, and is conducive to connecting functional modules of electronic components such as sensors on the robot body. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is a schematic structural diagram of a flexible connector constructed according to a preferred embodiment of the present invention;

[0025] Figure 2 It is a schematic diagram of the forming idea and method of the flexible connection structure constructed according to the preferred embodiment of the present invention;

[0026] Figure 3 is a schematic cross-sectional view of a flexible connector constructed according to a preferred embodiment of the present invention;

[0027] Figure 4 This is a brief flow chart of the crystal template method according to the preferred embodiment 1 of the present invention;

[0028] Figure 5 is a schematic diagram of a flexible connector constructed according to preferred embodiment 2 of the present invention;

[0029] Figure 6 This is a brief flow chart of the stent method for forming according to the preferred embodiment 2 of the present invention;

[0030] Figure 7 is a schematic diagram of a flexible connector constructed according to preferred embodiment 3 of the present invention;

[0031] Figure 8 is a schematic diagram of a flexible connector constructed according to preferred embodiment 4 of the present invention;

[0032] Figure 9 is a schematic diagram of a flexible connector constructed according to a preferred embodiment 5 of the present invention;

[0033] Figure 10 is a cross-sectional schematic diagram of a flexible connector constructed according to a preferred embodiment 5 of the present invention;

[0034] Figure 11 It is a schematic diagram of a flexible connector constructed according to preferred embodiment 6 of the present invention.

[0035] Throughout the drawings, the same reference numerals are used to denote the same elements or structures, wherein:

[0036] 1-first flexible body, 2-second flexible body, 3-porous structure. DETAILED DESCRIPTION

[0037] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely for the purpose of explaining the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

[0038] This invention exploits the fluidity of uncured flexible materials and their elasticity after curing. A porous structure is first formed on the first flexible member (1), and then the soft material forming the second flexible member (2) fills the pores. After curing, the two materials interweave between the first and second flexible members (1, 2), forming a three-dimensional mesh-like transition layer with a large surface area. The combined effects of intermolecular forces between the surfaces of the different flexible members and the elastic forces of the same materials achieve a reliable connection between the two flexible members of different materials.

[0039] like Figure 2 As shown, the preparation method of the flexible body interconnected structure based on the porous structure is as follows:

[0040] The porous connection structure is mainly formed by a multi-step casting method. Among them, the porous structure 3, which plays a core role in the connection, can be formed by two methods: casting method and non-casting method.

[0041] For the two first flexible bodies 1 and the second flexible bodies 2 that need to be connected, two molds are used to form them in sequence.

[0042] First, the first flexible body 1 and the porous structure 3 thereon are formed. At this time, the casting method or the non-casting method can be used for forming according to the requirements.

[0043] The second flexible body 2 is then cast and formed. Since it is cast and formed directly on the first flexible body 1 and the porous structure 3 , a space for loading the first flexible body 1 is reserved on the mold of the second flexible body 2 .

[0044] Forming of porous structure: divided into casting method and non-casting method

[0045] (1) Casting method

[0046] The porous structure is prepared by casting method, which can be divided into two types: crystal template method and scaffold method.

[0047] A Taking the crystal template method as an example, the preparation process is as follows Figure 4 As shown:

[0048] Place crystal particles into the groove of the mold until the groove is filled and smooth the top;

[0049] (a) Begin pouring, allowing the uncured soft material to completely submerge the crystal particles and fill the mold; create a vacuum or negative pressure environment during pouring to remove bubbles in the liquid;

[0050] (b) The soft material is solidified and formed, and the demolded flexible body is placed in a dissolving liquid and placed in an ultrasonic device to shatter and dissolve the crystals, thereby forming a porous structure 3 on the first flexible body 1; the body is removed and dried for the next step of casting.

[0051] (c) placing the prepared first flexible body 1 into the mold of the second flexible body 2 according to the correct connection position; casting the second flexible body 2 under a vacuum or negative pressure environment, and ensuring that the uncured soft material of the second flexible body 2 fully penetrates into the porous structure 3; and curing the whole and demolding it.

[0052] Furthermore, materials used to cast the flexible body include but are not limited to platinum-catalyzed silicone rubber (Ecoflex), polydimethylsiloxane (PDMS), hydrogel, etc. The crystalline particles include but are not limited to water-soluble sugar, salt, iodine soluble in carbon tetrachloride, etc.

[0053] The selection of the crystal particle size and the arrangement structure should be such that the porosity of the formed porous structure is between 50% and 55%.

[0054] B If the support method is used, the crystal is replaced with a pre-printed support structure.

[0055] In the crystal template method, the scaffold is placed in a specific dissolving solution to dissolve it, and an ultrasonic water bath or magnetic stirring is used to assist the dissolution.

[0056] Materials used to make the scaffold include, but are not limited to, high-impact polystyrene (HIPS), acrylonitrile butadiene styrene (ABS), polyvinyl butyrate (PVB), and polyvinyl alcohol (PVA). These are all commonly used 3D printing materials. The corresponding dissolving solutions primarily consist of limonene, acetone, isopropyl alcohol, and water.

[0057] The scaffold method can form a more complex three-dimensional porous structure.

[0058] (2) Non-casting method:

[0059] Non-casting methods for forming porous structures can include 3D printing, laser forming, and self-growth. Use silicone rubber soft materials that meet the requirements to directly form porous structures.

[0060] The present invention will be further described below with reference to specific embodiments.

[0061] Example 1

[0062] Figure 1 Schematic diagram of the flexible connector in Example 1. The flexible connector structure includes a first flexible body 1 and a porous structure 3 thereon and a second flexible body 2.

[0063] The first flexible body 1 and the porous structure 3 thereon are formed first, and then the second flexible body 2 is formed.

[0064] When the second flexible body 2 is formed, the fluidity of the uncured silicone rubber material is utilized to gradually fill the pores of the porous structure 3. After solidification, the original porous structure becomes a three-dimensional network structure formed by interweaving the two materials.

[0065] Figure 3 The figure shows a cross-sectional schematic diagram of the flexible connector in the first embodiment. The first flexible body 1 and the second flexible body 2 are interwoven with each other in the three-dimensional mesh connection structure to achieve a stable connection.

[0066] In this embodiment, the material used for the first flexible body 1 and the porous structure 3 thereon is platinum-catalyzed silicone rubber (Ecoflex 00-10), and the material used for the second flexible body 2 is food-grade mold silicone rubber (model E620).

[0067] Figure 4 The figure shows a simplified flow chart of the crystal template method. This embodiment adopts this method, and the specific molding steps are as follows:

[0068] The core process is the formation of the porous structure 3. Example 1 is prepared by the crystal template method. Figure 4 This is its preparation process.

[0069] S1 Forming of the first flexible body

[0070] (1) Place crystal particles into the groove until the groove is filled, and smooth the top. In Example 1, the crystals are sugar cubes.

[0071] (2) Prepare the material of the first flexible body 1. Use a syringe to draw Ecoflex00-10A and Ecoflex00-10B, mix them in a volume ratio of 1:1, stir for 1-2 minutes, put them into a vacuum pump to evacuate, let them stand for 5-8 minutes and then exhaust them.

[0072] (3) Pouring: Pour the above materials into the mold cavity, completely immersing the sugar cubes and filling the mold. Pouring is done under vacuum or negative pressure to remove air bubbles in the material.

[0073] (4) Place the mold filled with the flexible material and sugar cubes in a constant temperature box and heat at 80°C for 40 minutes to solidify the mold.

[0074] (5) The solidified sugar block-silicone rubber mixture is placed in distilled water and placed in an ultrasonic device with a power controlled at 280W-320W for 2-3 hours to break up and dissolve the sugar block. At this time, a porous structure 3 is formed on the first flexible body 1.

[0075] (6) After ultrasonic treatment, the first flexible body 1 and the porous structure 3 thereon are dried to prepare for the next step of casting.

[0076] S2 Forming of the second flexible body

[0077] (7) Place the prepared first flexible body 1 into the molding mold of the second flexible body 2 according to the correct connection position.

[0078] (8) Prepare the material of the second flexible body 2. Use a syringe to absorb food-grade mold silicone (E620) A and B, mix them in a volume ratio of 1:1, stir for 1-2 minutes, put them into a vacuum pump to evacuate, and let them stand for 5-8 minutes before exhausting.

[0079] (9) Using the above materials, cast the second flexible body 2 under vacuum or negative pressure, and ensure that the uncured soft material of the second flexible body 2 fully penetrates into the porous structure 3.

[0080] (10) The mold is placed in a constant temperature box and heated at 80°C for 45 minutes to solidify the mold. After taking it out, a flexible connector is obtained.

[0081] Example 2

[0082] With respect to the first embodiment, when the porous structure is formed by the crystal template method, the arrangement of the crystals needs to rely on the support of the mold, and the shape of the pores formed depends on the shape of the crystals.

[0083] Figure 5 This is a schematic diagram of the flexible connector in Example 2. Using the scaffolding method to form a porous structure allows for the creation of diverse pore shapes and more precise control of porosity by controlling the shape of the preformed scaffolds as needed. Furthermore, the layout of the scaffolds does not require a mold structure.

[0084] Furthermore, in this embodiment, the material used for the first flexible body 1 and the porous structure 3 thereon is platinum-catalyzed silicone rubber (Ecoflex 00-30), and the material used for the second flexible body 2 is polydimethylsiloxane (PDMS).

[0085] Figure 6 The following is a brief flow chart of the molding process using the stent method. Example 2 uses this method, and the specific molding steps are as follows:

[0086] S1 Forming of the first flexible body

[0087] (1) Place the bracket into the mold. The bracket is pre-formed using a 3D printing additive manufacturing process. In Example 2, the bracket is made of polyvinyl alcohol (PVA).

[0088] (2) Prepare the material of the first flexible body 1. Use a syringe to absorb Ecoflex00-30A and Ecoflex00-30B, mix them in a volume ratio of 1:1, stir for 1-2 minutes, put them into a vacuum pump to evacuate, let them stand for 5-8 minutes and then exhaust them.

[0089] (3) Pouring: Pour the above materials into the mold cavity, completely immersing the bracket and filling the mold. Pouring is done under vacuum or negative pressure to remove bubbles in the material.

[0090] (4) Place the mold filled with the flexible material and the bracket in a constant temperature box and heat it at 80°C for 40 minutes to solidify it.

[0091] (5) The cured scaffold-silicone rubber mixture is placed in distilled water. Dissolution can be achieved in two ways. One is by placing it in a magnetic stirrer at 1200 rpm and stirring for 5-6 hours to dissolve the scaffold. The other is by placing it in an ultrasonic water bath. After 4-5 hours, the scaffold dissolves. At this point, the porous structure 3 on the first flexible body 1 is formed.

[0092] (6) After the porous structure 3 is formed, the first flexible body 1 and the porous structure 3 thereon are dried to prepare for the next step of casting.

[0093] S2 Forming of the second flexible body

[0094] (7) Place the prepared first flexible body 1 into the molding mold of the second flexible body 2 according to the correct connection position.

[0095] (8) Prepare the material of the second flexible body 2 by mixing PDMS prepolymer A and crosslinker B in a ratio of 10:1, stirring with a glass rod for 5 minutes to make the mixture uniform, and then vacuuming for 30 minutes to completely remove bubbles.

[0096] (9) Using the above materials, cast the second flexible body 2 under vacuum or negative pressure, and ensure that the uncured soft material of the second flexible body 2 fully penetrates into the porous structure 3.

[0097] (10) The mold is placed in a constant temperature box and cured at 80°C for 60 minutes. The flexible connector is then taken out.

[0098] Example 3

[0099] Figure 7 The figure shows the structure of the flexible connector in Example 3. The porous structures 3 are arranged at the four corners of the first flexible body 1 .

[0100] The first flexible body 1 and the porous structure thereon can be formed by using 3D printing technology or laser processing technology.

[0101] Among the materials that can be used for 3D printing are thermoplastic polyurethane (TPU) and silicone rubber.

[0102] As for laser processing, processing is performed on the basis of the existing first flexible body 1 to produce the required porous structure 3.

[0103] The molding of the second flexible body 2 is the same as that of the aforementioned embodiment 1 or embodiment 2.

[0104] Example 4

[0105] Figure 8 Shown is a schematic structural diagram of the flexible connector of Example 4.

[0106] The flexible connector in the fourth embodiment can be formed based on the crystal template method in the first embodiment, the bracket method in the second embodiment, or the 3D printing technology and laser processing technology in the third embodiment, and the forming process will not be described in detail.

[0107] Considering the complexity of actual use scenarios, the three-dimensional mesh connection structure can be arranged in an array. The array arrangement can more evenly distribute the connection force, thereby improving the reliability and life of the flexible connector.

[0108] Example 5

[0109] Figure 9 Shown is a schematic structural diagram of the flexible connector of Example 5.

[0110] The flexible connector in the fifth embodiment can be formed based on the bracket method in the second embodiment or the 3D printing technology and laser processing technology in the third embodiment, and the forming process will not be described in detail.

[0111] When the second flexible body 2 is formed, when the prepared material is poured into the mold, the liquid material may not be able to fully penetrate the porous structure 3 due to poor fluidity of some materials or unsatisfactory negative pressure or vacuum environment in the mold.

[0112] like Figure 10 The figure shows a cross-sectional schematic diagram of the flexible connector of the fifth embodiment. By utilizing the characteristic that the porosity decreases from top to bottom in the fifth embodiment, the material used to form the second flexible body 2 first passes through the portion with larger porosity during casting, and then gradually penetrates into the portion with smaller porosity, which is conducive to the downward flow of the material and sufficient penetration of the porous structure 3.

[0113] In addition, the penetration speed of the material for forming the second flexible body 2 can also be increased by pressure casting.

[0114] The characteristic of the porosity decreasing from top to bottom can be controlled by designing the structural characteristics of the bracket according to needs or controlling the processing of 3D printing and laser forming.

[0115] Example 6

[0116] The flexible body module connection method provided by the present invention is particularly suitable for the field of soft robot module connection.

[0117] Figure 11 The figure shows the structure of the flexible connector of embodiment 4. The connector in this embodiment is a bionic foot with integrated sensors, which can be formed based on the crystal template method of embodiment 1 or the bracket method of embodiment 2.

[0118] The first flexible body 1 is a sensing layer with a sensor, and the second flexible body 2 is a bionic foot body.

[0119] Through the flexible body module connection method provided by this patent, a three-dimensional mesh connection structure is formed between the first flexible body 1 and the second flexible body 2, and the bionic foot as the structural main body is connected to the sensor module with information collection function, thereby realizing the connection between flexible body modules with different functions.

[0120] It will be easily understood by those skilled in the art that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A flexible body interconnected structure based on a porous structure, characterized in that: The structure includes a first flexible body and a second flexible body, wherein the first flexible body is provided with a three-dimensional mesh porous structure, and the second flexible body is connected to the first flexible body by filling the porous structure of the first flexible body, thereby forming a flexible body interconnected structure; The first flexible body is platinum-catalyzed silicone rubber, polydimethylsiloxane, hydrogel or thermoplastic polyurethane.

2. The flexible body interconnection structure based on a porous structure according to claim 1, characterized in that: The second flexible body is platinum-catalyzed silicone rubber, polydimethylsiloxane or hydrogel.

3. The flexible body interconnection structure based on a porous structure according to claim 1, characterized in that: The total porosity of the three-dimensional network porous structure is 30% to 70%.

4. An application of the flexible body interconnection structure based on a porous structure according to any one of claims 1 to 3 in a soft robot.

5. A method for forming a flexible interconnected structure based on a porous structure according to any one of claims 1 to 3, characterized in that: The method comprises the following steps: S1 uses a casting method or a non-casting method to form a first flexible body having a three-dimensional mesh porous structure; S2: pouring the material of the second flexible body into the first flexible body, and obtaining the required flexible interconnected structure after solidification.

6. The molding method according to claim 5, wherein: The non-casting method adopts 3D printing, laser processing or self-growth molding.

7. The molding method according to claim 5, wherein: The casting method adopts a crystal template method or a bracket method for casting and forming.

8. The molding method according to claim 7, wherein: The crystal particles used in the crystal template method are a combination of one or more of sugar, salt, and iodine soluble in water.

9. The molding method according to claim 7, wherein: The material of the scaffold in the scaffold method includes high impact polystyrene, acrylonitrile-butadiene-styrene, polyvinyl butyrate or polyvinyl alcohol, and the main components of the corresponding dissolving solution are limonene, acetone, isopropyl alcohol and water.

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