Self-cleaning organic silicon foam with micro-nano structure super-hydrophobic surface as well as preparation method and application of self-cleaning organic silicon foam

Abstract

The invention relates to the technical field of high polymer materials, in particular to self-cleaning organic silicon foam with a micro-nano structure and a super-hydrophobic surface and a preparation method of the self-cleaning organic silicon foam. The surface structure of the release film is customized through one-step molding transfer printing, and a release agent of the release film contains a super-hydrophobic modified organic silicon light diffusion agent. The light diffusant is mainly silicon dioxide or organic silicon resin microspheres modified by surface long-chain silane. The surface structure of the customized release film is an inverted pyramid-shaped micro-nano structure. The organic silicon foam obtained according to the process has the surface micro-nano structure, super-hydrophobic and self-cleaning functions, and is particularly suitable for manufacturing daily and industrial pads such as mouse pads, table mats and placemats.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of high polymer materials, in particular to a self-cleaning organic silica foam with a micro-nano structure super-hydrophobic surface, a preparation method and application thereof. BACKGROUND

[0002] Traditional mouse pads are usually made of rubber, cloth, plastic or leather. These materials have the following common defects during use: Easy to stain and retain: the surface is prone to stains such as sweat, oil, beverage stains and dust, making it difficult to clean and affecting the appearance and hygiene.

[0003] Bacterial growth: the surface pores are easy to retain dirt, becoming a breeding ground for bacteria and mold, and long-term contact may pose a potential threat to user health.

[0004] Cleaning inconvenience: cloth pads are difficult to dry after washing, and stains on the surface of rubber or plastic pads need to be repeatedly wiped with cleaning agents, which is time-consuming and labor-intensive.

[0005] Environmental and odor problems: some low-quality materials may contain volatile organic compounds, producing unpleasant odors and being difficult to degrade.

[0006] Organic silica foam is an ideal mouse pad substrate due to its softness, high resilience, high and low temperature resistance, non-toxicity and environmental friendliness. However, its surface energy is still relatively high, and it has a certain affinity for oily substances, so stains may still penetrate or adhere. In the prior art, a super-hydrophobic coating is sprayed to impart self-cleaning ability to the surface, but the coating has the problems of poor wear resistance, easy peeling and short service life.

[0007] Therefore, it is of great market value and practical significance to develop an organic silica foam material with a body that has a durable and stable super-hydrophobic self-cleaning ability. SUMMARY

[0008] The present application aims to overcome the shortcomings of the prior art and provide an organic silica foam that is self-cleaning, super-hydrophobic, stain-resistant, bacteria-resistant, odor-free and environmentally friendly. The super-hydrophobic performance of the foam is due to the integrated micro-nano structure on the surface of the material, rather than an additional coating, thereby solving the problem of coating wear. The present application also provides a preparation method for the foam.

[0009] The present application provides a self-cleaning organic silica foam with a micro-nano structure super-hydrophobic surface, a preparation method and application thereof. The foam is formed by foaming an organic silica glue as the main body. The foam surface has a biomimetic, integrated inverted pyramid micro-nano composite structure, and the structure surface is rich in super-hydrophobic modified organic silica light diffuser, so that the contact angle of the surface with water is greater than 150° and the rolling angle is less than 10°, thereby realizing super-hydrophobic and self-cleaning functions.

[0010] In some embodiments, the inverted-pyramid micro-nano structure is transferred to the surface of the uncured silicone foam slurry by a customized release film, and is fixed after being heated and cured.

[0011] The inverted-pyramid micro-nano composite structure is an array of densely arranged inverted-pyramid protrusions (similar to inverted triangles, but with a sharp tip or a platform structure at the top).

[0012] The unit size of the inverted-pyramid protrusion structure is micrometer level, with a side length of 10-100 μm and a height of 5-50 μm.

[0013] Further, the preparation method of the customized release film is as follows: on the surface of a PET film, an array of densely arranged inverted-pyramid micro-pit structures (micrometer level structures, with a side length of 10-100 μm and a depth of 5-50 μm) is prepared by laser engraving or photolithography technology. (The nanometer level rough structure is that the light diffuser is shaped at the bottom of the pyramid, and the engraved release film-micrometer and the light diffuser-nanometer of the release agent are micro-nano structures together).

[0014] Further, a layer of special release agent is coated on the surface of the release film, and the formula of the release agent comprises: Basic components: vinyl silicone oil, hydrogen-containing silicone oil, platinum catalyst, inhibitor, and other conventional addition-cured silicone release agent components.

[0015] Key modified components: 15%~30% wt of super-hydrophobic modified silicone light diffuser. The light diffuser is silica (SiO2) or silicone resin microspheres (particle size 0.1-5 μm) whose surface is modified by fluorosilane or long-chain alkyl (-C8-C18) silane, which itself serves as part of the release agent for easy peeling, and as a super-hydrophobic functional filler and light diffuser.

[0016] In some preferred cases, the light diffuser comprises silica microspheres modified by dodecyl triethoxysilane, and other modifiers include hexadecyl trimethoxysilane, octadecyl trichlorosilane, octyl trimethoxysilane, etc. Dodecyl triethoxysilane modified silica microspheres or silicone resin microspheres: 0.5 g of hydrophilic silica or resin microspheres are dispersed in 50 mL of anhydrous ethanol, and ultrasonic treatment is performed for 30 minutes to fully disperse them. 1 mL of dodecyl triethoxysilane is added to the dispersion. The reaction is carried out under magnetic stirring reflux at 60°C for 6-12 hours. After the reaction, centrifugal separation is performed, and the product is washed with ethanol multiple times, and then dried in a vacuum drying oven at 60°C to obtain super-hydrophobic SiO2 powder or super-hydrophobic resin microspheres.

[0017] The preparation method of the self-cleaning silicone foam with a micro-nano structure super-hydrophobic surface according to the present application comprises the following steps: Customized release film preparation: a release film with inverted pyramid-shaped micro-nano structure and surface coated with super-hydrophobic modified silicone light diffuser release agent is prepared, and after baking and curing, a release film with super-hydrophobic micro-nano structure is obtained.

[0018] Preparation of silicone foam slurry: the foam slurry is divided into AB two components, the silicone oil A component includes hydroxyl silicone oil, vinyl silicone oil, catalyst. The B component contains hydrogen silicone oil, vinyl silicone oil, inhibitor. The foaming slurry is configured by AB components in a mass ratio of 1:1.

[0019] Molding: the foam slurry is coated or injected into a mold, then the microstructure surface of the customized release film is used as an inner liner to cover the surface of the slurry, ensuring that the slurry is fully filled into the micro-nano structure of the release film, and then further adhered by a pressure roller.

[0020] Heating and curing foaming: under heating conditions (such as 80-120℃), the silicone slurry undergoes foaming reaction and curing, at the same time, the super-hydrophobic modified silicone light diffuser in the release agent migrates to the surface of the foam and chemically bonds with the foam body.

[0021] Peeling and post-processing: after cooling, the release film is peeled off from the cured silicone foam, and a permanent inverted pyramid-shaped convex micro-nano structure opposite to the release film is obtained on the surface of the foam, and the structure surface is rich in super-hydrophobic components. Finally, the final product is obtained after cutting and trimming.

[0022] The customized release film is prepared with inverted pyramid structure on the surface of the base film by laser engraving or photoetching technology.

[0023] In some preferred cases, a PET film with a thickness of 70-75 μm is selected for the preparation of the customized release film. An ultraviolet laser engraving technology is used to process an array of inverted pyramid-shaped micro-pits on the surface of the PET film. Each micro-pit is a square opening with a side length of 10-100 μm and a depth of 20-30 μm, and the pit wall has a nanoscale roughness. The center-to-center distance of the micro-pits is 30-60 μm.

[0024] Another technical solution of the present application is the application of the self-cleaning silicone foam with micro-nano structure super-hydrophobic surface in the preparation of mouse pads, table pads, dining pads or anti-stain pads.

[0025] The beneficial effects of the present application are: True self-cleaning of the body: the super-hydrophobic function is realized through the surface micro-nano structure and the modification of the body material, rather than an easy-to-shed coating, so it is wear-resistant and durable, with a life consistent with the product itself.

[0026] Excellent hydrophobic and oleophobic properties: the inverted pyramid structure can effectively trap air and form an air film, greatly reducing the contact area between liquid droplets and solids. Combined with a low-surface-energy superhydrophobic modifier, it achieves strong repellency to common liquids such as water, coffee, cola, and soy sauce. Dirt can be blown off or wiped off with a paper towel.

[0027] Antibacterial and antifungal properties: the surface cannot retain liquid and nutrients, which inhibits the growth of bacteria and mold from the root.

[0028] Environmentally friendly and healthy: the main material is organic silicon, which is non-toxic and odorless, with very low VOCs content, and is friendly to the human body and the environment.

[0029] Comfortable and practical: it maintains the softness, high resilience, and quietness of organic silicone foam, and has a comfortable feel. When used as a mouse pad, it is accurate in positioning.

[0030] Process innovation: cleverly using the release film manufacturing process, the microstructure forming and surface superhydrophobic modification are combined into one step, which is simple and suitable for large-scale industrial production. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 A self-cleaning organic silicone foam with a micro-nano structure superhydrophobic surface. DETAILED DESCRIPTION

[0032] To make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor are within the scope of protection of the present application.

[0033] Embodiment 1: specific preparation steps of a self-cleaning organic silicone foam with a micro-nano structure superhydrophobic surface 1. Preparation of custom release film: Base film microstructure processing: a PET film with a thickness of 75 μm is selected. An inverted pyramid-shaped micro-pit array is processed on the surface of the PET film using ultraviolet laser engraving technology. Each micro-pit is a positive pyramid-shaped opening with a side length of 50 μm and a depth of 30 μm, and the pit wall has a nanoscale roughness. The center-to-center distance of the micro-pits is 60 μm.

[0034] Release agent formulation: 100 parts of vinyl silicone oil (viscosity 1000 mPa-s), 40 parts of hydrogen-containing silicone oil (hydrogen content 0.8%), 1 part of platinum catalyst (Karstedt, 3000 ppm), 0.5 parts of ethynylcyclohexanol inhibitor were mixed uniformly by weight parts. Then, 22 parts of silica microspheres modified by dodecyl triethoxysilane (average particle size 1.5 μm, as super-hydrophobic modified silicone light diffuser) were added and uniformly dispersed at high speed.

[0035] Coating and curing: the prepared release agent was coated on the surface of the microstructured PET film by microgravure coating, and the wet thickness was 5 μm. Then, the release agent was cured at 100°C for 1 minute to form a customized release film with super-hydrophobic function.

[0036] 2. Preparation of silicone foam Foam slurry formulation: the silicone oil A component includes 100 parts by weight of vinyl-terminated polydimethylsiloxane (viscosity 100,000 mPa-s), 2 parts of hydroxyl silicone oil (hydroxyl value 8.5%), 0.1 parts of catalyst platinum catalyst (Karstedt, 5000 ppm). The B component vinyl silicone oil 100 parts by weight of vinyl-terminated polydimethylsiloxane (viscosity 100,000 mPa-s), 1 part of hydrogen-containing silicone oil (hydrogen content 0.75%), 0.1 parts of inhibitor ethynylcyclohexanol. The foaming slurry is configured by AB components in a mass ratio of 1:1.

[0037] Molding: the above customized release film with microstructure as the lower film, the slurry is poured on the surface of the film material, then the microstructure surface of the above customized release film is used as the upper cover, and the slurry surface is carefully covered with a pressure roller. Place in an oven at 110°C for 10 minutes, during which the silicone slurry completes the foaming and curing reaction. Take out from the oven, cool to room temperature, take out the cured silicone foam from the mold, and carefully peel off the release film from the surface of the foam. At this time, the foam surface perfectly replicates the dense array of pyramid protruding structures opposite to the release film relief.

[0038] Example 2: High modifier content scheme The difference from Example 1 is only that in the preparation of the release agent, the addition amount of silica microspheres modified by dodecyl triethoxysilane is increased to 30 parts.

[0039] Example 3: Low modifier content scheme The difference from Example 1 is only that in the preparation of the release agent, the addition amount of silica microspheres modified by dodecyl triethoxysilane is reduced to 15 parts.

[0040] Example 4: The difference from Example 2 is only that the dodecyl triethoxysilane is replaced by octyl trimethoxysilane when formulating the release agent.

[0041] Example 5: The difference from Example 2 is only that the dodecyl triethoxysilane is replaced by octadecyl trichlorosilane when formulating the release agent.

[0042] Example 6: The difference from Example 2 is only that the dodecyl triethoxysilane is replaced by octyl trimethoxysilane when formulating the release agent.

[0043] Example 7: The difference from Example 2 is only that the silane-modified silica microspheres are replaced by silicone resin microspheres.

[0044] Comparative Example 1: No micro-structured surface (smooth surface) The preparation process is exactly the same as Example 1, but a conventional release film with smooth surface (no micro-structure) is used, and 22 parts of dodecyl triethoxysilane-modified silica microspheres are also added to the release agent, i.e.: Base film micro-structure processing: PET film with a thickness of 75 μm is selected. Release agent formulation: 100 parts of vinyl silicone oil (viscosity 1000 mPa·s), 40 parts of hydrogen-containing silicone oil (hydrogen content 0.8%), 1 part of platinum gold catalyst (3000 ppm), and 0.5 parts of ethynylcyclohexanol inhibitor are mixed uniformly by weight. Then, 22 parts of dodecyl triethoxysilane-modified silica microspheres (average particle size 1.5 μm, as super-hydrophobic modified silicone light diffuser) are added and dispersed uniformly at high speed.

[0045] Comparative Example 2: No super-hydrophobic modifier (only structure) The preparation process is exactly the same as Example 1, but the release agent used is a conventional release agent without any super-hydrophobic modified silica microspheres (i.e. the release agent obtained without adding dodecyl triethoxysilane-modified silica microspheres).

[0046] Comparative Example 3: Post-spraying treatment scheme (simulation of prior art) The same smooth surface silicone foam product as in Comparative Example 1 is used. Then a commercially available super-hydrophobic nano-spray (Sinograce nano-hydrophobic spray) is sprayed on the surface, and left to cure for 24 hours.

[0047] Table 1: Test results of Examples 1-3 and Comparative Examples 1-3 for preparing self-cleaning silicone foam with micro-nano structured super-hydrophobic surface

[0048] 5000 abrasion test: sandpaper rubbing: the coated surface is rubbed with standard 400 mesh sandpaper under 10g weight pressure, the contact angle value is recorded after 5000 rubs.

[0049] Self-cleaning effect evaluation: evenly sprinkle simulated pollutants (such as silica powder, graphite powder, dust, pollen, etc.) on the surface of the coating. The sample is inclined at about 15-30 degrees. Use a micropipette or a spray device to simulate rainfall, and let the water droplets roll over the contaminated area. Observe whether the water droplets can "wrap" and completely remove the pollutants, leaving a clean path. A superior coating will exhibit very clean and thorough cleaning.

[0050] Through the above comparison of examples and comparative examples, it can be concluded that the present application (examples 1-7) has both micro-nano structure and surface chemical modification, achieving excellent and durable super-hydrophobic self-cleaning performance. Neither chemical modification alone (comparative example 1) nor physical structure alone (comparative example 2) can achieve the technical effect of the present application, proving that the synergistic effect of structure and function is crucial. Compared with existing post-processing technology (comparative example 3), the present application embeds the function in the body, and the wear resistance and durability are improved by orders of magnitude, solving the long-standing technical bottleneck in this field.

[0051] In the description of the present specification, the description of the terms "one embodiment / way", "some embodiments / ways", "example", "specific example" or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment / way or example are included in at least one embodiment / way or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment / way or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any appropriate manner in any one or more embodiments / ways or examples. In addition, the skilled in the art can combine and combine the different embodiments / ways or examples described in the present specification and the features of the different embodiments / ways or examples without contradiction.

[0052] It has to be noted that, in the present application, terms like "first", "second", and the like in the description and in the claims are used to distinguish between similar elements and not necessarily to describe a sequential or chronological order. Furthermore, the terms "comprises", "comprising", or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can also include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element proceeded by "comprises... a" does not, without more constraints, exclude the presence of additional identical elements in the process, method, article, or apparatus that comprises the element. The term "plurality" denotes two or more, for example two, three or four unless expressly specified otherwise.

[0053] The foregoing is considered as illustrative only of the principles of the application. Numerous modifications and changes will readily occur to those skilled in the art, and the generic principles defined herein can be applied to other embodiments without departing from the spirit or scope of the application. Accordingly, the scope of the application is indicated by the appended claims rather than by the foregoing description, and all changes that come within the meaning and range of equivalents are intended to be embraced therein.

Claims

1. A self-cleaning silicone foam with a micro-nano structured superhydrophobic surface, characterized in that, The at least one surface of the foam has an integrally formed inverted-pyramid micro-nano composite structure, and the structure surface is rich in super-hydrophobic modified silicone light diffuser, so that the surface presents super-hydrophobic characteristics.

2. The self-cleaning silicone foam with micro-nano structured superhydrophobic surface according to claim 1, characterized in that, The super-hydrophobic modified silicone light diffuser is silica or silicone resin microspheres whose surface is modified by fluorosilane or long-chain alkylsilane.

3. A self-cleaning silicone foam with a micro-nano structured superhydrophobic surface for preparing the self-cleaning silicone foam with a micro-nano structured superhydrophobic surface according to claim 1 or 2, characterized in that, The particle size of the silica or silicone resin microspheres is 0.1-5 μm. 4.The self-cleaning silicone foam with micro-nano structure super-hydrophobic surface of claim 1, wherein, The inverted-pyramid micro-nano composite structure is an array of densely arranged inverted-pyramid protrusions. 5.The self-cleaning silicone foam with micro-nano structured superhydrophobic surface of claim 4, wherein, The unit size of the inverted-pyramid protrusion structure is in microns, with a side length of 10-100 μm and a height of 5-50 μm.

6. A release film for producing the silicone foam according to any one of claims 1 to 5, characterized in that, The release film has a release surface with inverted-pyramid micro-nano structure, and the release agent coated on the surface of the release film contains 15%-30% wt of super-hydrophobic modified silicone light diffuser.

7. A method for preparing the self-cleaning silicone foam with micro-nano structured superhydrophobic surface according to any one of claims 1-5, characterized in that, The method comprises the following steps: (1) Preparing a release film, coating a release agent on the base film with inverted-pyramid micro-nano structure by microgravure coating, and baking and curing to obtain a customized release film with super-hydrophobic function; (2) Coating or injecting silicone foam slurry into a mold; (3) Covering the microstructure surface of the customized release film as an inner liner on the surface of the silicone foam slurry, so that the slurry fills the micro-nano structure of the release film; (4) Heating at 80-120°C to make the silicone slurry foam and solidify, and at the same time, make part of the super-hydrophobic modified silicone light diffuser in the release agent migrate to the surface of the foam and chemically bond with the foam body; (5) Cooling and peeling off the release film to obtain silicone foam with inverted-pyramid micro-nano composite structure and super-hydrophobic characteristics on the surface.

8. The method of claim 7, wherein, The release film is prepared by laser engraving or photoetching technology on the surface of the base film to form inverted-pyramid micro-nano structure.

9. The method of claim 7, wherein, The silicone foam slurry is mixed by two components A and B in a mass ratio of 1:1; wherein, Component A includes vinyl silicone oil, hydroxyl silicone oil, and platinum catalyst; Component B includes vinyl silicone oil, hydrogen-containing silicone oil, and inhibitor.

10. Use of the self-cleaning silicone foam with micro-nano structure super-hydrophobic surface according to any one of claims 1-5 in the preparation of mouse pads, table pads, dining pads, or anti-pollution pads.

Images