Silicone porous material and method for manufacturing the same

Abstract

To enhance a tear strength of a silicone porous body having a three-dimensional communication pore structure.SOLUTION: A silicone porous body having such a three-dimensional communication pore structure that an organic system is contained in a silicone rubber base material forming a skeleton can be produced by mixing a liquid silicone raw material, a water-soluble bubble forming material and an organic fiber such as polyethylene to form a silicone mixture, subjecting the mixture to addition reaction to obtain a crosslinked silicone molding, then bringing the silicone molding into contact with water and extracting and removing the water-soluble bubble forming material; and can improve a tear strength of a silicone porous body. At this time, the tear strength exceeding 20% is improved compared to a silicone porous body containing no organic fiber by containing 1 wt.% or more of the organic fiber in a silicone resin of the silicone rubber base material.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] This invention relates to a silicone porous body having a three-dimensional interconnected pore structure and a method for producing the same.

Background Art

[0002] A silicone porous body having three-dimensionally interconnected pores is excellent in flexibility and air permeability, and is used in various applications such as cosmetic puffs and various filters by utilizing its properties. Such a silicone porous body is known to be produced by an extraction method in which a foaming agent is previously mixed and dispersed in a main material and then the foaming agent is removed to form bubbles (cavities). Such an extraction method is roughly classified into a wet method and a dry method. (1) The wet method is performed by dissolving the main material in a solvent, mixing and dispersing a foaming agent therein, molding it into a predetermined shape, and then dissolving and removing the foaming agent. Further, (2) the dry method is performed by mixing a foaming agent with the main material in a molten state by heating, molding it into a predetermined shape, and then dissolving and removing the foaming agent. Such wet and dry methods require dissolution of the main material in a solvent or heating and melting, and have drawbacks such as increased labor in the process. Another extraction method is the emulsion method. This is a method in which water and / or a water-soluble foaming agent is mixed and dispersed in a liquid main material, then a main material formed into a predetermined shape is obtained, and then water or a water-soluble polymer is removed from this main material (for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Incidentally, while porous silicone materials have advantages such as flexibility and breathability due to their three-dimensional interconnected pore structure, as mentioned above, their structure means that increasing the proportion of pores (porosity) relatively reduces their tear strength.

[0005] In other words, the present invention aims to provide a silicone porous material that does not feel like a foreign object when compressed with a finger and has excellent tear strength, as well as a method for manufacturing the same. [Means for solving the problem]

[0006] The means for solving the aforementioned problems and achieving the intended objective is a silicone porous body in which a three-dimensional interconnected pore structure is formed on a silicone rubber substrate by extracting and removing the pore-forming material from a silicone molded body containing the pore-forming material, wherein the silicone rubber substrate contains organic fibers. According to this invention, by including organic fibers in the silicone rubber substrate that forms the skeleton of the silicone porous body, a firm skeleton can be formed, resulting in a silicone porous body with a three-dimensional interconnected pore structure and excellent tear strength.

[0007] Another method involves including 1 wt% or more of the organic fibers in the silicone resin of the silicone rubber substrate. According to this invention, the tear strength can be improved by more than 20% compared to a porous silicone body that does not contain organic fibers.

[0008] In summary, another means for solving the aforementioned problems and achieving the intended objective is a dispersion step of mixing a silicone raw material, a water-soluble foam-forming agent, and organic fibers to form a silicone mixture; a crosslinking step of crosslinking the silicone mixture to form a silicone molded body; and an extraction and removal step of bringing the silicone molded body into contact with water to extract and remove the water-soluble foam-forming agent. According to this invention, organic fibers can be included in the silicone rubber substrate that forms the skeleton of the silicone porous body, and a silicone porous body with a three-dimensional interconnected pore structure that forms a firm skeleton and has excellent tear strength can be obtained.

[0009] Another method involves mixing the organic fiber with the silicone raw material in an amount of 1 wt% or more to form the silicone mixture. According to this invention, the tear strength can be improved by more than 20% compared to a porous silicone body formed without mixing in organic fibers. [Effects of the Invention]

[0010] According to the present invention, a silicone porous material can be obtained that does not feel like a foreign object when touched by compressing it with a finger and has excellent tear strength. [Brief explanation of the drawing]

[0011] [Figure 1] This is a schematic process diagram illustrating the method for manufacturing a porous silicone material according to the present invention. [Modes for carrying out the invention]

[0012] Next, the silicone porous body and its manufacturing method according to the present invention will be described with reference to preferred examples. The inventors of the present application have found that in a silicone porous body formed by mixing a silicone raw material, a water-soluble foam-forming agent, and organic fibers to obtain an uncrosslinked silicone mixture in which the foam-forming agent is dispersed, then crosslinking this silicone mixture to form a silicone rubber substrate made of silicone resin, and then extracting and removing the foam-forming agent with water, the inclusion of an organic material in the silicone rubber substrate results in a robust framework for the three-dimensional interconnected pore structure and excellent tear strength.

[0013] The silicone raw material may be either one-component or two-component, but a liquid silicone that remains liquid at room temperature is used. In the case of a two-component type, it is preferable because it is easy to control the timing of initiating the crosslinking reaction and mixing during the process of crosslinking can be suppressed. Furthermore, as the silicone raw material, a condensation reaction crosslinking type raw material may be used, or an addition reaction crosslinking type raw material may be used. In this case, it is preferable to use an addition reaction crosslinking type silicone raw material that does not release by-products during crosslinking. The room-temperature curing silicone raw material used in the present invention is a material used to make prototype molds, and after adding a curing agent to the main component, it is stirred, air entrained during mixing is removed by degassing under reduced pressure, and then cured and cured. This curing involves injecting the silicone raw material into the mold and holding it at room temperature for about one day, after which demolding is possible immediately.

[0014] Any water-soluble bubble-forming material can be used as the aforementioned water-soluble bubble-forming material, provided that it is soluble in water and, when mixed with the silicone raw material at a temperature of 100°C or lower, the bubble-forming material is uniformly and stably dispersed in the silicone raw material. This bubble-forming material contains at least one water-soluble inorganic substance and at least one water-soluble organic substance. For example, water-soluble inorganic substances include NaCl (salt), KCl, CaCl, NH4Cl, NaNO3, NaNO2, etc.

[0015] Examples of water-soluble organic substances include TME (trimethylolethane), trimethylolpropane, trimethylolbutane, sucrose, soluble starch, sorbitol, glycine, or sodium salts of various organic acids (malic acid, citric acid, glutamic acid, succinic acid, etc.). Other water-soluble organic substances that can be used include polyethylene glycol derivatives such as polyethylene glycol, polyethylene glycol diacrylate, polyethylene glycol dioleate, and polyethylene glycol diacetate, compounds derived from alkyl ethers represented by formula (1) R1O(CH2CH2O)nR2, and other compounds that dissolve in water and reduce the viscosity of the resin. Here, R1 in formula (1) is a hydrocarbon group, and R2 represents hydrogen or a hydrocarbon group. Furthermore, R1 and R2 may be saturated or unsaturated hydrocarbon groups. Polyethylene glycol is preferably used because it has a high melt flow and high water solubility. Furthermore, the molecular weight of polyethylene glycol is preferably in the range of 2,000 to 30,000, more preferably 5,000 to 25,000, and even more preferably 15,000 to 25,000. As for the water-soluble organic substance, one derived from the structure R1O(CH2CH2O)nR2 is appropriately selected if it is in a liquid state at temperatures from 0°C to 100°C. Using one derived from the structure R1O(CH2CH2O)nR2 has the advantage of increasing the dispersibility of the water-soluble inorganic substance in the silicone raw material, resulting in a homogeneous mixture. Moreover, even when the silicone mixture is molded and crosslinked, the water-soluble inorganic substance maintains good dispersibility in the resulting silicone molded article, maintaining a homogeneous mixed state.

[0016] Examples of the aforementioned organic fibers include various chemical fibers such as polyamide fibers like nylon, polyvinyl alcohol fibers, polyvinylidene chloride fibers, polyvinyl chloride fibers, polyester fibers, polyacrylonitrile fibers, polyethylene fibers, polypropylene fibers, and polyurethane fibers. By using a silicone porous body containing such organic fibers, superior tear strength can be achieved compared to a silicone porous body that does not contain organic fibers. Furthermore, a silicone porous body containing organic fibers can achieve superior tear strength improvement compared to cases where inorganic fibers are included. In addition, it is not necessary to use only one type of organic fiber; multiple different types of organic fibers can be mixed. Such organic fibers have excellent physical properties such as flexibility and tensile strength, and the organic fibers flexibly deform in accordance with the deformation of the silicone rubber substrate formed by crosslinking of the silicone raw material, thereby increasing the tear strength of the silicone rubber substrate. Here, the organic fibers used have a melting point above the crosslinking temperature for crosslinking the silicone raw material. Specifically, it is preferable to use organic fibers with a melting point of 100°C to 260°C. By using organic fibers with such a melting point, it is possible to prevent the organic fibers from melting during crosslinking of the silicone raw material. Suitable organic fibers include polypropylene fibers, polyethylene fibers, polyester fibers, or polyamide fibers. In particular, ultra-high molecular weight polyethylene fibers are suitable because they can achieve both tear strength and flexibility in the porous silicone material.

[0017] Furthermore, while the fiber length of the organic fibers is not particularly limited, it is preferable to use organic fibers with a fiber length of 0.2 to 10 mm, and more preferably 0.4 mm or longer. By using such a fiber length, the organic fibers can follow the deformation of the silicone rubber substrate and deform, and the tear strength of the silicone rubber substrate can be increased. In other words, if the fiber length of the organic fibers is less than 0.2 mm, the organic fibers themselves are likely to break easily, and it is highly likely that the tear strength of the porous silicone material cannot be sufficiently improved. Also, if the fiber length is 10 mm or longer, it is highly likely that the organic fibers will not follow the deformation of the silicone rubber substrate sufficiently, resulting in a foreign body sensation. Furthermore, while the fiber diameter of the organic fibers is not particularly limited, it is preferable to use organic fibers with a fiber diameter of 1 to 100 μm, and more preferably The fiber diameter is 10 to 90 μm. By using such a fiber diameter, the organic fibers can follow the deformation of the silicone rubber substrate and deform, and the tear strength of the silicone rubber substrate can be increased. In other words, if the fiber diameter of the organic fibers is less than 1 μm, the organic fibers themselves are likely to break easily, and it is highly likely that the tear strength of the porous silicone material cannot be sufficiently improved. On the other hand, if the fiber diameter is 100 μm or more, the organic fibers may not follow the deformation of the silicone rubber substrate sufficiently, and it is highly likely that a foreign body sensation will occur.

[0018] Furthermore, the organic fibers preferably constitute 0.5 wt% or more of the silicone resin in the silicone rubber substrate, and more preferably 1 wt% or more. In other words, by including 0.5 wt% or more of organic fibers relative to the silicone rubber substrate (silicone resin), the tear strength of the porous silicone body can be increased. Moreover, by including 1 wt% or more of organic fibers relative to the silicone rubber substrate (silicone resin), the tear strength of the porous silicone body containing organic fibers can be increased by 20% or more compared to a porous silicone body formed under the same conditions without organic fibers. In addition, for porous silicone bodies containing more than 10 wt% of organic fibers relative to the silicone rubber substrate (silicone resin), it becomes difficult to form the porous body structure (three-dimensional interconnected pore structure) shape during crosslinking of the silicone raw material. For this reason, the content (percentage) of organic fibers is preferably in the range of 0.5 to 10 wt% relative to the silicone resin in the silicone rubber substrate, and preferably in the range of 1 to 9 wt%.

[0019] It is preferable to prepare the mixture obtained by mixing the silicone raw material with a water-soluble foam-forming agent in such a way that the raw materials do not contain water (H2O). That is, the mixed raw materials do not contain water and / or an aqueous solution of the water-soluble foam-forming agent, and the silicone raw material and the water-soluble foam-forming agent are mixed directly. If water (H2O) is mixed into the mixture, a homogeneous three-dimensional interconnected pore structure may not be formed during the crosslinking process depending on the degree of evaporation of the water component, and the porous material may have inconsistent air permeability or inferior physical strength.

[0020] When the total blending weight of the silicone raw material and the water-soluble bubble-forming material (water-soluble inorganic substance and water-soluble organic substance) is 100 wt%, the mixing ratio (wt%) of the silicone raw material and the water-soluble bubble-forming material (water-soluble inorganic substance and water-soluble organic substance) is preferably in the range of 6:94 to 36:64. When the silicone raw material is less than 6 wt%, it becomes difficult for the silicone molded body itself to maintain its shape during the extraction and removal of the water-soluble bubble-forming material. On the other hand, when the water-soluble bubble-forming material is less than 64 wt%, a sufficient number of bubbles may not be formed in the silicone molded body, and a three-dimensional interconnected pore structure may not be formed.

[0021] The mixing ratio (mixing ratio) of the water-soluble inorganic substance and the water-soluble organic substance that constitute the water-soluble bubble-forming material is preferably in the range where the weight ratio of the two is 9:91 to 97:3. When the water-soluble inorganic substance is less than 9, a structure of a three-dimensionally interconnected silicone porous body cannot be obtained, and when it exceeds 97, the extraction ratio of the water-soluble bubble-forming material decreases and a sufficient bubble ratio, that is, porosity cannot be obtained.

[0022] When the mixing ratio of the silicone raw material and the water-soluble bubble-forming material (water-soluble inorganic substance and water-soluble organic substance) is set within the above-mentioned range, by immersing water in the silicone molded body formed from these mixtures, the water-soluble bubble-forming material can be easily and sufficiently extracted and removed. That is, the water-soluble organic substance existing so as to wrap the water-soluble inorganic substance can be dispersed in a continuously networked state, and the water-soluble inorganic substance can be removed together with the water-soluble organic substance by immersing the silicone molded body in water. Thereby, a silicone porous body having a three-dimensional interconnected pore structure with the silicone raw material as the main material and having homogeneity and strength can be obtained.

[0023] Figure 1 shows the manufacturing process of the silicone porous body according to the present invention. By adding a water-soluble foaming agent and organic fibers to a silicone raw material as a main raw material and mixing them at a temperature of 100°C or lower, a silicone mixture in which the foaming agent and organic fibers are uniformly dispersed in the silicone raw material is obtained (dispersion step). At this stage, the silicone mixture is in an uncrosslinked state. The obtained silicone mixture is passed through a biaxial roll or the like to be formed into a predetermined shape, and the obtained silicone molded body is crosslinked (crosslinking step). Next, the silicone molded body is immersed in water or warm water at a predetermined temperature to extract and remove the water-soluble foaming agent (extraction and removal step), whereby a silicone porous body having a three-dimensional interconnected pore structure containing organic fibers is obtained.

[0024] For the mixing of the aforementioned silicone raw material, water-soluble foaming agent and organic fibers, a single-screw or double-screw extruder, kneader, pressure kneader, conical kneader, Banbury mixer, Henschel mixer, rotor mixer or other mixers are preferably used. No special device is required for this mixing, and the mixing speed etc. are not limited either. The temperature during mixing may be below the melting point temperature of the organic fibers and can be carried out at room temperature. Heating promotes the crosslinking of the silicone raw material, but when the environmental temperature is low, the viscosity of the mixed raw material becomes high, resulting in poor productivity and efficiency. Therefore, it is preferable to heat the appropriately formulated raw material and apply it to the mixer. Also, if excessive crosslinking occurs in the intermediate molded product, flexibility and softness are lost in the subsequent sheet forming process, or the crosslinked molecular structure becomes a foreign substance in the form of a gel, resulting in product defects. The mixing time depends on the physical properties of the mixture, but it is sufficient if the mixture is sufficiently mixed, and usually about 15 to 30 minutes is fine. Mixing for too long may cause the crosslinking of the silicone raw material, which is the main material, to progress during the mixing process, which may be a factor in not obtaining a good silicone porous body, so attention is required. The mixed raw material can be formed into a required shape by extrusion, injection, pressing or rollers, but extrusion with high mass productivity or injection capable of forming a complex shape is particularly preferable.

[0025] The silicone mixture obtained by mixing each component is molded into the desired shape, and the resulting silicone molded body is crosslinked. The water-soluble bubble-forming agent is extracted and removed by immersing the resulting silicone molded body in water, which is the solvent, for a predetermined time (for example, 10 to 48 hours, depending on the shape and thickness of the silicone molded body). Since the silicone raw material of the present invention crosslinks at room temperature, molding is performed by varying the crosslinking temperature and time. That is, if the crosslinking temperature is room temperature, crosslinking can be achieved by leaving it for 72 hours, and if it is 40°C, crosslinking can be achieved by leaving it for 24 hours. The crosslinking temperature can be high as long as the bonding reaction of the silicone is not inhibited, and it is also possible to heat it to 100 to 150°C for 7 minutes to 7 hours. For example, if the crosslinking temperature is 130°C, crosslinking can be achieved by heating for about 10 minutes.

[0026] Subsequently, the silicone molded body is immersed in a solvent. While there are no particular limitations on the immersion method, extraction and removal by immersion in water, where the entire silicone molded body is in contact with water, is preferred. The temperature of the water used at this time is also not particularly limited and may be around room temperature, but warm water at 15-90°C may be used for efficient removal of each water-soluble substance. Then, the molded body from which the water-soluble bubble-forming material has been removed is dried to obtain a porous silicone body. The drying temperature is not particularly limited, but should be below the heat resistance temperature of the porous silicone body obtained from the silicone raw material and below the melting point temperature of the organic fiber.

[0027] This allows for the inclusion of organic fibers in the silicone rubber substrate that forms the framework of the porous silicone body, resulting in a robust framework and a three-dimensional interconnected pore structure with excellent tear strength. This enhances durability when used in cosmetic puffs, various filters, and other applications, and diversifies the uses of the porous silicone body. In particular, it is preferable to form the silicone mixture by mixing 0.5 wt% or more of organic fibers with the silicone raw material. That is, by mixing 0.5 wt% or more of organic fibers with the silicone raw material to form the porous silicone body, the tear strength of the porous silicone body can be increased. Furthermore, by mixing 1 wt% or more of organic fibers with the silicone rubber substrate (silicone resin) to form the porous silicone body, the tear strength of the porous silicone body containing organic fibers can be increased by 20% or more compared to a case where the porous silicone body is formed under the same conditions without organic fibers. However, when more than 10 wt% of organic fibers are mixed with the silicone raw material, it becomes difficult to maintain the shape of the silicone raw material during crosslinking. Therefore, it is preferable that the mixing ratio of organic fibers to the silicone raw material be in the range of 0.5 to 10 wt%. Furthermore, by using an addition-reaction type silicone raw material that does not generate by-products during crosslinking, it is possible to form a porous silicone material in which the content (ratio) of organic fibers to the silicone resin of the silicone rubber substrate is in the range of 0.5 to 10 wt% by setting the mixing ratio of organic fibers to the silicone raw material to 0.5 to 10 wt%.

[0028] [Experimental Examples] Below are experimental examples of the silicone porous body according to the present invention. This silicone porous body is formed by mixing a pre-selected silicone raw material, a water-soluble foam-forming agent (water-soluble inorganic and water-soluble organic substances), and organic fibers in predetermined proportions. The resulting silicone mixture is then molded into a predetermined plate shape using a general-purpose extruder, twin-screw roll, hot press, etc., and the water-soluble foam-forming agent is removed to form the silicone porous body. Subsequently, in accordance with Japanese Industrial Standard JIS K6252:2007, an angle-shaped test piece with no cuts, 2.0 mm thick and 100 mm long, was prepared from the silicone porous body using a punching die, and its tear strength (N / mm) was measured. The results for each experimental example and comparative example are shown in Tables 1 and 2. Here, the silicone raw material is a two-component addition reaction type liquid silicone (manufactured by Momentive, trade name: TSE3453T) that does not generate by-products during crosslinking, and the water-soluble inorganic substance is NaCl (manufactured by Nippon Seien Co., Ltd., trade name: Yakishio). The same materials are used in all experimental examples and comparative examples. Furthermore, the water-soluble organic substance used in each experimental example and comparative example is an alkyl ether represented by formula (1) above, selected from water-soluble organic substance 1 where R1 = an alkyl group with 12 carbon atoms, R2 = H, and n = 7, and water-soluble organic substance 2 where R1 = R2 = an alkyl group with 1 carbon atom (methyl group), and n = 4.

[0029] Below, Table 1 or Table 2 shows the measurement results for a porous silicone body without organic fibers as a comparative example, and a porous silicone body containing organic fibers, inorganic fibers, or additives as an experimental example. (Comparative Example 1) A total of 5 L of base material was prepared, consisting of 13 wt% silicone raw material, 72 wt% water-soluble inorganic material, and 15 wt% water-soluble organic material 1, with a total blending weight of 100 wt% of silicone raw material and water-soluble foam-forming agent (water-soluble inorganic and water-soluble organic 1). This mixture was stirred for 20 minutes at 100 rpm using a planetary mixer (Aikousha Seisakusho Co., Ltd.) to form an uncrosslinked silicone mixture. The stirring temperature was 40°C. This silicone mixture was molded into a sheet-like silicone molded body using a hot press set to 130°C, and this sheet-like silicone molded body was heated for 10 minutes to crosslink the molded body. The crosslinked sheet-like silicone molded body was immersed in warm water heated to 90°C for 24 hours to extract the water-soluble inorganic material and water-soluble organic material 1. Subsequently, by drying in a dryer (100°C), a porous silicone material was obtained in which numerous air bubbles were interconnected in three dimensions within the sheet-like molded body.

[0030] (Comparative Example 2) A total of 5 L of base material was prepared, with a total weight of 100 wt% of silicone raw material and water-soluble foam-forming agent (water-soluble inorganic and water-soluble organic 1), consisting of 6 wt% silicone raw material, 81 wt% water-soluble inorganic material, and 13 wt% water-soluble organic 1, and the same procedure as in Comparative Example 1 was followed. By sequentially crosslinking to form a sheet-like silicone molded body, and then extracting a water-soluble inorganic substance and a water-soluble organic substance 1, a porous silicone body was obtained in which numerous air bubbles are interconnected in three dimensions within the sheet-like molded body.

[0031] (Experimental Example 1) In Experimental Example 1, a base material was prepared by mixing a silicone raw material, a water-soluble inorganic substance, and a water-soluble organic substance 1 in the same proportions as in Comparative Example 1. 3.75 wt% of organic fiber 1 was then mixed with the silicone raw material. The base material containing organic fiber 1 was stirred and crosslinked using the same procedure as in Comparative Example 1 to form a sheet-like silicone molded body. After that, the water-soluble inorganic substance and water-soluble organic substance 1 were extracted to obtain a porous silicone body in which numerous bubbles were interconnected in three dimensions within the sheet-like molded body. The organic fiber 1 in Experimental Example 1 is an ultra-high molecular weight polyethylene fiber (manufactured by Toyobo Co., Ltd., product name: Izanas), with a fiber length of 0.4 mm and a fiber diameter of 80 μm. That is, the mixing ratio of organic fiber 1 to the silicone raw material in Experimental Example 1 was 3.75 wt%, and the content ratio of organic fiber 1 to the silicone resin in the silicone rubber substrate was 3.75 wt%.

[0032] (Experimental Example 2) In Experimental Example 2, a base material was prepared by mixing a silicone raw material, a water-soluble inorganic substance, and a water-soluble organic substance 1 in the same proportions as in Comparative Example 1. 3.75 wt% of organic fiber 2 was then mixed with the silicone raw material. The base material containing organic fiber 2 was stirred and crosslinked using the same procedure as in Comparative Example 1 to form a sheet-like silicone molded body. After that, the water-soluble inorganic substance and water-soluble organic substance 1 were extracted to obtain a porous silicone body in which numerous bubbles were interconnected in three dimensions within the sheet-like molded body. The organic fiber 2 in Experimental Example 2 is an ultra-high molecular weight polyethylene fiber (manufactured by Toyobo Co., Ltd., product name: Izanas), with a fiber length of 0.8 mm and a fiber diameter of 80 μm. That is, the mixing ratio of organic fiber 2 to the silicone raw material in Experimental Example 2 was 3.75%, and the content ratio of organic fiber 2 to the silicone resin in the silicone rubber substrate was 3.75 wt%.

[0033] (Experimental Example 3) In Experimental Example 3, a base material was prepared by mixing a silicone raw material, a water-soluble inorganic substance, and a water-soluble organic substance 1 in the same proportions as in Comparative Example 1. 1 wt% of organic fiber 2 was then mixed with the silicone raw material, and the base material containing organic fiber 2 was stirred and crosslinked using the same procedure as in Comparative Example 1 to form a sheet-like silicone molded body. After that, the water-soluble inorganic substance and water-soluble organic substance 1 were extracted to obtain a porous silicone body in which numerous bubbles were interconnected in three dimensions within the sheet-like molded body. Specifically, in Experimental Example 3, the mixing ratio of organic fiber 2 to the silicone raw material was 1 wt%, and the content ratio of organic fiber 2 to the silicone resin in the silicone rubber substrate was 1 wt%.

[0034] (Experimental Example 4) In Experimental Example 4, a base material was prepared by mixing a silicone raw material, a water-soluble inorganic substance, and a water-soluble organic substance 1 in the same proportions as in Comparative Example 1. 8 wt% of organic fiber 2 was then mixed with the silicone raw material, and the base material containing organic fiber 2 was stirred and crosslinked using the same procedure as in Comparative Example 1 to form a sheet-like silicone molded body. After that, the water-soluble inorganic substance and water-soluble organic substance 1 were extracted to obtain a porous silicone body in which numerous air bubbles were interconnected in three dimensions within the sheet-like molded body. Specifically, in Experimental Example 4, the mixing ratio of organic fiber 2 to the silicone raw material was 8 wt%, and the content ratio of organic fiber 2 to the silicone resin in the silicone rubber substrate was 8 wt%.

[0035] (Experimental Example 5) In Experimental Example 5, a base material was prepared by mixing a silicone raw material, a water-soluble inorganic substance, and a water-soluble organic substance 1 in the same proportions as in Comparative Example 1. 3.75 wt% of organic fiber 3 was then mixed with the silicone raw material. The base material containing organic fiber 3 was stirred and crosslinked using the same procedure as in Comparative Example 1 to form a sheet-like silicone molded body. After that, the water-soluble inorganic substance and water-soluble organic substance 1 were extracted to obtain a porous silicone body in which numerous bubbles were interconnected in three dimensions within the sheet-like molded body. The organic fiber 3 in Experimental Example 5 is an ultra-high molecular weight polyethylene fiber (manufactured by Toyobo Co., Ltd., product name: Izanas), with a fiber length of 2 mm and a fiber diameter of 80 μm. That is, the mixing ratio of organic fiber 3 to the silicone raw material in Experimental Example 5 was 3.75 wt%, and the content ratio of organic fiber 3 to the silicone resin of the silicone rubber substrate was 3.75 wt%.

[0036] (Experimental Example 6) In Experimental Example 6, a base material was prepared by mixing a silicone raw material, a water-soluble inorganic substance, and a water-soluble organic substance 1 in the same proportions as in Comparative Example 1. 3.75 wt% of organic fiber 4 was then mixed with the silicone raw material. The base material containing the organic fiber 4 was stirred and crosslinked using the same procedure as in Comparative Example 1 to form a sheet-like silicone molded body. After that, the water-soluble inorganic substance and water-soluble organic substance 1 were extracted to obtain a porous silicone body in which numerous air bubbles were interconnected in three dimensions within the sheet-like molded body. The organic fiber 4 in Experimental Example 6 is an ultra-high molecular weight polyethylene fiber (manufactured by Toyobo Co., Ltd., product name: Izanas), with a fiber length of 5 mm and a fiber diameter of 80 μm. That is, the mixing ratio of organic fiber 4 to the silicone raw material in Experimental Example 6 was 3.75 wt%, and the content ratio of organic fiber 4 to the silicone resin of the silicone rubber substrate was 3.75 wt%.

[0037] (Experimental Example 7) In Experimental Example 7, a total of 5 L of base material was prepared, with a total weight of 100 wt% of silicone raw material and water-soluble foam-forming agent (water-soluble inorganic and water-soluble organic 2), consisting of 13 wt% silicone raw material, 72 wt% water-soluble inorganic material, and 15 wt% water-soluble organic 2. Then, 3.75 wt% of the above-mentioned organic fiber 2 was mixed with this silicone raw material, and the base material containing the organic fiber 2 was stirred and crosslinked in the same procedure as in Comparative Example 1 to form a sheet-like silicone molded body. After that, the water-soluble inorganic material and water-soluble organic 2 were extracted to obtain a porous silicone body in which numerous bubbles were interconnected in three dimensions on the sheet-like molded body. In other words, the mixing ratio of organic fiber 2 to the silicone raw material in Experimental Example 7 was 3.75%, and the content ratio of organic fiber 2 to the silicone resin of the silicone rubber substrate was 3.75 wt%.

[0038] (Experimental Example 8) In Experimental Example 8, a base material was prepared by mixing a silicone raw material, a water-soluble inorganic substance, and a water-soluble organic substance 1 in the same proportions as in Comparative Example 1. 3.75 wt% of organic fiber 5 was then mixed with the silicone raw material. The base material containing the organic fiber 5 was stirred and crosslinked using the same procedure as in Comparative Example 1 to form a sheet-like silicone molded body. After that, the water-soluble inorganic substance and water-soluble organic substance 1 were extracted to obtain a porous silicone body in which numerous bubbles were interconnected in three dimensions within the sheet-like molded body. The organic fiber 5 in Experimental Example 8 is a polyamide fiber (manufactured by Daiwabo Polytech Co., Ltd., product name: NZ), with a fiber length of 10 mm and a fiber diameter of 24 μm. That is, the mixing ratio of organic fiber 5 to the silicone raw material in Experimental Example 8 was 3.75 wt%, and the content ratio of organic fiber 5 to the silicone resin of the silicone rubber substrate was 3.75 wt%.

[0039] (Experimental Example 9) In Experimental Example 9, a base material was prepared by mixing a silicone raw material, a water-soluble inorganic substance, and a water-soluble organic substance 1 in the same proportions as in Comparative Example 1. 3.75 wt% of organic fibers 6 were then mixed with the silicone raw material. The base material containing the organic fibers 6 was stirred and crosslinked using the same procedure as in Comparative Example 1 to form a sheet-like silicone molded body. After that, the water-soluble inorganic substance and water-soluble organic substance 1 were extracted to obtain a porous silicone body in which numerous air bubbles were interconnected in three dimensions within the sheet-like molded body. The organic fibers 6 in Experimental Example 9 are polypropylene fibers (manufactured by Daiwabo Polytech Co., Ltd., product name: PZ), with a fiber length of 3 mm and a fiber diameter of 18 μm. That is, the mixing ratio of organic fibers 6 to the silicone raw material in Experimental Example 9 was 3.75 wt%, and the content ratio of organic fibers 6 to the silicone resin of the silicone rubber substrate was 3.75 wt%.

[0040] (Experimental Example 10) In Experimental Example 10, a base material was prepared by mixing a silicone raw material, a water-soluble inorganic substance, and a water-soluble organic substance 1 in the same proportions as in Comparative Example 2. 3.75 wt% of organic fiber 2 was then mixed with the silicone raw material. The base material containing organic fiber 2 was stirred and crosslinked using the same procedure as in Comparative Example 1 to form a sheet-like silicone molded body. After that, the water-soluble inorganic substance and water-soluble organic substance 1 were extracted to obtain a porous silicone body in which numerous bubbles were interconnected in three dimensions within the sheet-like molded body. Specifically, the content of organic fiber 2 in Experimental Example 10 relative to the silicone raw material was 3.75 wt%, and the ratio of organic fiber 2 to the silicone resin of the silicone rubber substrate was 3.7 wt%.

[0041] (Experimental Example 11) In Experimental Example 11, a base material was prepared by mixing a silicone raw material, a water-soluble inorganic substance, and a water-soluble organic substance 1 in the same proportions as in Comparative Example 1. 3.75 wt% inorganic fibers were then mixed with the silicone raw material, and the base material containing the inorganic fibers was stirred and crosslinked using the same procedure as in Comparative Example 1 to form a sheet-like silicone molded body. After that, the water-soluble inorganic substance and water-soluble organic substance 1 were extracted to obtain a porous silicone body in which numerous air bubbles were interconnected in three dimensions within the sheet-like molded body. The inorganic fibers in Experimental Example 11 were glass fibers (manufactured by Toyobo Co., Ltd., product name: PE9575), with a fiber length of 4 mm and a fiber diameter of 40 μm.

[0042] (Experimental Example 12) In Experimental Example 12, a base material was prepared by mixing a silicone raw material, a water-soluble inorganic substance, and a water-soluble organic substance 1 in the same proportions as in Comparative Example 1. An additive (inorganic filler) was then added to the silicone raw material at a concentration of 3.75 wt%. The base material containing inorganic fibers was then stirred and crosslinked in the same procedure as in Comparative Example 1 to form a sheet-like silicone molded body. After that, the water-soluble inorganic substance and water-soluble organic substance 1 were extracted to obtain a porous silicone body in which numerous bubbles were interconnected in three dimensions within the sheet-like molded body. The additive (inorganic filler) in Experimental Example 12 was calcium carbonate with an average particle size of 8 μm (manufactured by Maruo Calcium Co., Ltd., product name: R Heavy Carbonate).

[0043] (Experimental Example 13) In Experimental Example 13, a base material was prepared by mixing a silicone raw material, a water-soluble inorganic substance, and a water-soluble organic substance 1 in the same proportions as in Comparative Example 1. 0.5 wt% of organic fiber 2 was then mixed with the silicone raw material. The base material containing organic fiber 2 was stirred and crosslinked using the same procedure as in Comparative Example 1 to form a sheet-like silicone molded body. After that, the water-soluble inorganic substance and water-soluble organic substance 1 were extracted to obtain a porous silicone body in which numerous bubbles were interconnected in three dimensions within the sheet-like molded body. Specifically, the mixing ratio of organic fiber 2 to the silicone raw material in Experimental Example 13 was 0.5 wt%, and the content ratio of organic fiber 2 to the silicone resin in the silicone rubber substrate was 0.5 wt%.

[0044] [Table 1]

[0045] [Table 2]

[0046] As shown in Table 1 or Table 2, the porous silicone materials containing organic fibers obtained in Experimental Examples 1-10 and 13 had good appearance and a good cellular structure obtained by water extraction. Furthermore, the tear strength (N / mm) of the porous silicone materials containing organic fibers obtained in Experimental Examples 1-10 showed an improvement of more than 20% compared to the porous silicone materials without organic fibers in Comparative Examples 1 and 2, which corresponded to the mixing ratio of the silicone raw material to the base raw material. Note that in Tables 1 and 2, the "Tear Strength UP Ratio" column represents the ratio of the tear strength (tear strength of the experimental example / tear strength of the comparative example) to the porous silicone material of Comparative Example 1 or Comparative Example 2 without organic fibers, expressed as a percentage. Values ​​~9, 11~13 are for Comparative Example 1, and experimental example 10 is for Comparative Example 2. However, although the appearance of the silicone porous material containing inorganic fibers obtained in experimental example 11 and the silicone porous material containing additives (inorganic fillers) obtained in experimental example 12 is good, the improvement in tear strength (N / mm) from the silicone porous material without organic fibers in Comparative Example 1 is less than 10% compared to when the same amount of organic fibers is mixed with the silicone raw material (experimental examples 1-10) (the tear strength UP ratio does not exceed 110%, indicating only a slight improvement in tear strength). In other words, silicone porous materials containing organic fibers in a silicone rubber substrate are superior in improving tear strength compared to silicone porous materials containing inorganic fibers or additives in the same proportion as the silicone rubber substrate. Furthermore, as can be seen from Experimental Example 13, a silicone porous material containing a small amount of organic fibers can achieve the same tear strength as a silicone porous material containing inorganic fibers or additives (inorganic fillers), demonstrating that it is possible to improve tear strength while suppressing the amount of organic fibers mixed with the silicone raw material. Moreover, the silicone porous materials containing organic fibers obtained in Experimental Examples 1-10 and 13 did not cause a foreign body sensation (prickly feeling) when the silicone porous material was compressed with a finger, and had a good tactile feel. On the other hand, the silicone porous material containing inorganic fibers in Experimental Example 11 caused a foreign body sensation (prickly feeling) when the silicone porous material was compressed with a finger, resulting in a reduced tactile feel.

[0047] In other words, as can be seen from the results of Experimental Examples 1-10 and Experimental Example 13, by crosslinking a silicone mixture formed by mixing a silicone raw material, a water-soluble foam-forming agent, and organic fibers to form a silicone molded body, and then extracting and removing the water-soluble foam-forming agent, it is possible to produce a porous silicone body containing 0.5 wt% or more of organic fibers in the silicone rubber substrate, thereby achieving excellent tear strength. Furthermore, from the results of Experimental Examples 1-10, it can be seen that by mixing 1-10 wt% of organic fibers with the silicone raw material to form the silicone mixture, it is possible to obtain a porous silicone body containing 1 wt% or more of organic fibers relative to the silicone resin of the silicone rubber substrate, and the tear strength can be improved by more than 20% compared to a porous silicone body that does not contain organic fibers.

Claims

1. A method for manufacturing a filter comprising a silicone porous body containing organic fibers and having a three-dimensional interconnected pore structure, satisfying any one of the following (1) to (5): The manufacturing process for the aforementioned porous silicone body is as follows: A dispersion step in which a silicone raw material, a water-soluble foam-forming agent, and organic fibers are mixed to form a silicone mixture, A crosslinking step to crosslink the aforementioned silicone mixture to form a silicone molded body, The process includes an extraction and removal step of bringing the silicone molded body into contact with water to extract and remove the water-soluble bubble-forming agent. A method for manufacturing a filter characterized by the following: (1) The organic fiber is a chemical fiber. (2) The melting point of the organic fiber is 100 to 260°C. (3) The fiber length of the organic fiber is 0.2 to 10 mm. (4) The fiber diameter of the organic fiber is 1 to 100 μm. (5) The density of the porous silicone material is 0.11 to 0.22 g / cm³. ３ That is

2. A cosmetic puff comprising a silicone porous body containing polyethylene fibers and having a three-dimensional interconnected pore structure, characterized in that the fiber length of the polyethylene fibers is 0.8 to 2 mm.

3. The cosmetic puff according to claim 2, wherein the fiber diameter of the polyethylene fiber is 1 to 100 μm.

4. The density of the aforementioned porous silicone material is 0.11 to 0.22 g / cm³. ３ The cosmetic puff according to claim 2 or claim 3.

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