Silicone elastomer nonwoven fabrics by electrospinning

Abstract

The present invention relates to a process for producing a polymeric material comprising: (i) at least one organic solvent; (ii) (A) at least one organopolysiloxane compound containing a group having an aliphatic carbon-carbon multiple bond; (B) at least one organopolysiloxane compound having a Si-bonded hydrogen atom, or instead of or in addition to (A) and (B), (C) at least one organopolysiloxane compound containing a Si-C bonded group having a group with an aliphatic carbon-carbon multiple bond and a Si-bonded hydrogen atom; (However, all of the above (A), (B) and (C) are performed at 25°C for 0.1 seconds.) -1 The viscosity measured at a shear rate of 800,000 mPa·s or less. (D) at least one hydrosilylation catalyst; (E) no filler or at least one silicone-containing filler; an addition-crosslinking silicone elastomer comprising (iii) 25°C, 0.1 s -1 at least one polysiloxane other than (A), (B), (C), and (E), having a viscosity of more than 5,000,000 mPa·s measured at a shear rate of Electrospinning solution comprising:

Description

[Technical Field]

[0001] The present invention relates to electrospinning solutions based on silicone elastomers and the use of the electrospinning solutions in the production of nonwoven fabrics by electrospinning. [Background technology]

[0002] Electrospinning is a well-known conventional technique for producing nonwoven fabrics with fiber diameters ranging from a few micrometers to a few nanometers. This technique involves applying a high voltage (approximately 10–15 kV) between a spinning nozzle (capillary) and a collector to spin polymer melts, solutions, and dispersions into submicron-sized fibers, which are then collected as a fibrous nonwoven fabric. This method allows for increased throughput by simply adding more nozzles. Details of the electrospinning process can be found, for example, in A. Greiner et al., Applied Chem (2007), Vol. 119, pp. 5770–5805. This article also highlights the variety of polymers already used in electrospinning processes. Electrospinning typically uses thermoplastic resins, either as melts or as solutions in suitable solvents.

[0003] Electrospun nonwovens are used, for example, in filtration, industrial and infectious disease prevention medical masks, and air purifiers, in which contaminated air is drawn in through an intake vent and passed through a series of filters by a blower. Fiber nonwovens with fiber diameters of a few micrometers to a few nanometers are particularly well-suited for filter media because they exhibit low pressure drop and high filtration efficiency. Filtration is based on the high specific surface area and low pressure drop of nanofibers, and therefore, the exhalation resistance is kept low by the high porosity of the corresponding fibrous nonwovens. The use of electrets to increase the filtration efficiency of air and respiratory filters is known. Electrets are dielectrics that permanently maintain an electric field. This property enhances the filter media's ability to attract and retain particles, such as airborne dust, pollutants, and fibers. This is usually achieved by using fluorinated polymers such as PTFE, because these materials have a particularly strong tendency to accumulate and retain a negative charge (i.e., on the negative side of the triboelectric series). Electrospinning is suitable for producing nanofibers with electret properties because the electric field used directly charges the nonwoven fabric. US Patent No. 8,801,998 B (corresponding to European Patent No. 2,557,206 B1) describes, as an example, an electret for a filter made of polyurethane fibers electrospun with nanoparticles of PTFE.

[0004] To enable autoclaving or sterilization of filter media, they must be stable against temperature and ionizing radiation. Therefore, these filter media do not use common plastics like polyester or polypropylene, but rather require high-melting-point thermoplastics such as specialized polyimides (PI) and polyetherimides (PEI). The limited melting and dissolving properties of these thermoplastics make their use in spinning processes costly and inconvenient. Silicone elastomers, on the other hand, are systems that can be crosslinked by temperature or ultraviolet light. Before crosslinking, the primary components are generally soluble in most aprotic solvents and typically reduce in viscosity with shear, making them pumpable and therefore easy to process. After crosslinking, silicone elastomers exhibit high mechanical flexibility and stability against temperature and radiation. Furthermore, silicones, which are on the negative side of the triboelectric series, exhibit a particularly high electron affinity at the surface of the material, making them easily capable of functioning as electrets.

[0005] Electrospinning of silicones is a known technique, typically performed using organic solvents. To form homogeneous fibers during electrospinning, the spinning solution must be sufficiently viscoelastic. To ensure viscoelasticity, it is known to add a high molecular weight hydrophilic polymer as a thickener. For example, Chinese Patent No. 109868559 discloses the successful electrospinning of a crosslinkable silicone composition (composed of polymethylhydrosiloxane (DVi)4 and hexachloroplatinic acid) using ethanol in the presence of polyvinylpyrrolidone (PVP). Silicones are also suitable for the coaxial electrospinning process, in which silicones are electrospun with typically hydrophilic, mutually immiscible polymers without premixing, resulting in core-shell fibers. The shell-forming polymer serves as the outer framework for fiber formation, while the silicone resides in the core of the electrospun fiber. For example, Chinese Patent No. 101498057 describes the electrospinning of PVP as a water-soluble polymer (shell) and silicone rubber (core). Silicone is soluble in dichloromethane, and PVP is soluble in ethanol. To obtain silicone fibers, the shell polymer is subsequently removed in a water washing step. U.S. Patent Application Publication No. 2014322512 (corresponding to International Publication No. 2014143866) describes a needleless electrospinning process for producing silicone PLGA core-shell fibers using a highly flowable silicone elastomer. The drawback of this method is that to obtain pure silicone fibers, the additional polymer must be removed in a post-electrospinning step. This removal step is usually performed in a water washing step. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] U.S. Patent No. 8801998B (corresponding to European Patent No. 2557206B1) [Patent Document 2] Chinese Patent No. 109868559 [Patent Document 3] Chinese Patent No. 101498057 [Patent Document 4] U.S. Patent Application Publication No. 2014322512 (corresponding to International Publication No. 2014143866)

[0007] [Non-Patent Document 1] A. Greiner et al., Applied Chem (2007), VOL.119, p.5770-5805 Summary of the Invention

[0008] It is therefore an object of the present invention to provide a silicone composition that does not have the above-mentioned drawbacks of the prior art and that can be used in electrospinning processes without additional polymers.

[0009] Surprisingly, it has been found that the electrospinning solution of the present invention achieves the above objectives. The solution of the present invention is suitable for use in an electrospinning process to produce nanofiber nonwoven fabrics composed solely of silicone. According to the present invention, the solution has at least a sufficient molecular weight and is electrospinned at 25°C for 0.1 seconds. -1 Organopolysiloxane (III) with a viscosity of 5,000,000 mPa·s or greater measured at a shear rate of 1000 s is crucial because of its potential impact on the shell during fiber formation. Since organopolysiloxane (III) is incorporated into the silicone elastomer network, optimal functional groups can be introduced as needed. Adding organopolysiloxane (III) to the electrospinning solution results in pure silicone fibers, eliminating the need for a subsequent washing step.

[0010] Therefore, the present invention provides (i) at least one organic solvent; (ii) (A) at least one organopolysiloxane compound containing a group having an aliphatic carbon-carbon multiple bond; (B) at least one organopolysiloxane compound having a Si-bonded hydrogen atom, or instead of or in addition to (A) and (B), (C) at least one organopolysiloxane compound containing a Si-C bonded group having a group with an aliphatic carbon-carbon multiple bond and a Si-bonded hydrogen atom; (However, all of the above (A), (B) and (C) are performed at 25°C for 0.1 seconds.) -1 The viscosity measured at a shear rate of 800,000 mPa·s or less. (D) at least one hydrosilylation catalyst; (E) no filler or at least one silicone-containing filler; an addition-crosslinkable silicone elastomer comprising (iii) 25°C, 0.1 s -1 at least one polysiloxane other than (A), (B), (C), and (E), having a viscosity of more than 5,000,000 mPa·s measured at a shear rate of The present invention provides an electrospinning solution comprising: DETAILED DESCRIPTION OF THE INVENTION

[0011] In order to avoid excessive page count in the description of the present invention, only preferred embodiments of each feature are described below, but it should be clearly understood by those skilled in the art that the present disclosure also expressly discloses and explicitly desires all combinations of different preferred levels.

[0012] Organic solvent (i) The solvent can be a single organic solvent or a mixture of various organic solvents. Suitable organic solvents include hydrocarbons, halogenated hydrocarbons, ethers, alcohols, aldehydes, ketones, acids, anhydrides, esters, nitrogen-containing compounds, sulfur-containing compounds, and organosilicon compounds. Common examples of hydrocarbons include pentane, hexane, dimethylbutane, heptane, 1-hexene, 1,5-hexadiene, cyclohexane, terpenes, benzene, isopropylbenzene, xylene, toluene, benzine, naphthalene, and terahydronaphthalene. Common examples of halogenated hydrocarbons include fluoroform, perfluoroheptane, methylene chloride, chloroform, carbon tetrachloride, 1,2-dichloroethane, 1,1,1-trichloroethane, tetrachloroethene, trichloroethene, chloropentane, bromoform, 1,2-dibromomethane, methylene iodide, fluorobenzene, chlorobenzene, and 1,2-dichlorobenzene. Common examples of ethers include diethyl ether, butyl ethyl ether, anisole, diphenyl ether, ethylene oxide, tetrahydrofuran, furan, triethylene glycol, and 1,4-dioxane. Common examples of alcohols include methanol, ethanol, propanol, butanol, octanol, cyclohexanol, benzyl alcohol, ethylene glycol, ethylene glycol monomethyl ether, propylene glycol, butyl glycol, glycerol, glycerin, phenol, and m-cresol. Common examples of aldehydes include acetaldehyde and butyraldehyde. Common examples of ketones include diisobutyl ketone, 2-butanone, cyclohexanone, and acetophenone. Common examples of acids include formic acid and acetic acid. Common examples of anhydrides include acetic anhydride and maleic anhydride. Common examples of esters include methyl acetate, ethyl acetate, butyl acetate, phenyl acetate, glyceryl trioctanoate, diethyl oxalate, dioctyl sebacate, methyl benzoate, dibutyl phthalate, DBE® (DuPont de Nemours), and tricresyl phosphate. Common examples of nitrogen-containing compounds include nitromethane, nitrobenzene, butyronitrile, acetonitrile, benzonitrile, malononitrile, hexylamine, ethanolamine, N,N-diethylethanolamine, aniline, pyridine, N,N-dimethylaniline, N,N-dimethylformamide, N-methylpiperazine, and 3-hydroxypropionitrile.Common examples of sulfur-containing compounds include carbon disulfide, methanethiol, dimethyl sulfone, dimethyl sulfoxide, and thiophene. Common examples of organosilicon compounds include linear or cyclic volatile siloxanes containing up to five silicon atoms, particularly hexamethyldisiloxane, octamethyltrisiloxane, decamethyltetrasiloxane, hexamethylcyclotrisiloxane, and octamethylcyclotetrasiloxane.

[0013] The electrospinning solution according to the present invention contains 30 to 98 mass %, particularly preferably 50 to 95 mass %, of the solvent (i).

[0014] Addition-crosslinking silicone elastomer composition (ii) It is known that the compounds (A), (B), and / or (C) used in the addition-crosslinking silicone elastomer composition (ii) of the present invention are selected to enable crosslinking. For example, compound (A) has at least two aliphatic unsaturated groups and (B) has at least three Si-bonded hydrogen atoms, or compound (A) has at least three aliphatic unsaturated groups and siloxane (B) has at least two Si-bonded hydrogen atoms. Furthermore, instead of compounds (A) and (B), siloxane (C) having aliphatic unsaturated groups and Si-bonded hydrogen atoms in the above-mentioned ratios may be used. A mixture of (A), (B), and (C) having aliphatic unsaturated groups and Si-bonded hydrogen atoms in the above-mentioned ratios may also be used.

[0015] Component (A) The silicone composition according to the present invention preferably contains at least one unsaturated organosilicon compound as component (A), and it is possible to use any of the aliphatic unsaturated organosilicon compounds that have been used up to now in addition crosslinking compositions, such as silicone block polymers having urea segments, silicone block polymers having amide segments and / or imide segments and / or esteramide segments and / or polystyrene segments and / or silylene segments and / or carborane segments, and silicone graft polymers having ether groups.

[0016] The organosilicon compound (A) containing an Si-C bonded group having an aliphatic carbon-carbon multiple bond used is preferably a linear or branched organopolysiloxane composed of units of the general formula (I): R 4 a R 5 b SiO (4-a-b) / 2 (I) (In the formula, R 4 are each independently the same or different organic or inorganic groups having no aliphatic carbon-carbon bonds, R 5 are each independently the same or different monovalent substituted or unsubstituted Si-C bonded hydrocarbon groups having at least one aliphatic carbon-carbon multiple bond, a is 0, 1, 2, or 3; b is 0, 1, or 2, However, the sum of a + b is 3 or less, and there are at least two R 5 (Condition: There must be a group.)

[0017] R 4 The group is a monovalent or polyvalent group, and examples of polyvalent groups include divalent, trivalent, and tetravalent groups, which may have a structure in which, for example, 2, 3, or 4 siloxy units of formula (I) are multiple-bonded to each other.

[0018] R 4Further examples of the monovalent groups are -F, -Cl, -Br, -OR 6 , -CN, -SCN, -NCO, and Si-C bonded substituted or unsubstituted hydrocarbon groups (which may be interrupted by oxygen atoms or -C(O)- groups), or divalent groups having Si bonds at both ends according to formula (I). 4 When the group is a Si-C bonded hydrocarbon substituent, preferred substituents are halogen atoms, phosphate groups, cyano groups, -OR 6 , -NR 6 -, -NR 6 2, -NR 6 -C(O)-NR 6 2. -C(O)-NR 6 2. -C(O)R 6 , -C(O)OR 6 , -SO2-Ph, and -CF 5 In this case, R 6 are each independently the same or different hydrogen atom or a monovalent hydrocarbon group having 1 to 20 carbon atoms, and Ph is a phenyl group.

[0019] R 4 Examples of groups include alkyl groups (e.g., methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tertiary butyl, n-pentyl, isopentyl, neopentyl, tertiary pentyl, hexyl, n-hexyl, heptyl, n-heptyl, octyl, n-octyl, isooctyl, 2,2,4-trimethylpentyl, nonyl, n-nonyl, decyl, n-decyl, dodecyl, and n-dodecyl). group, and octadecyl group, n-octadecyl group), cyclic alkyl groups (e.g., cyclopentyl, cyclohexyl, cycloheptyl, and methylcyclohexyl), aryl groups (e.g., phenyl, naphthyl, anthryl, and phenanthrene), alkaryl groups (e.g., o-, m-, and p-tolyl groups, xylyl group, and ethylphenyl group), aralkyl groups (e.g., benzyl group, and α- and β-phenylethyl groups), and the like.

[0020] R 4Examples of the substituents include haloalkyl groups (e.g., 3,3,3-trifluoropropyl, n-propyl, 2,2,2,2',2',2'-hexafluoroisopropyl, and heptafluoroisopropyl), haloaryl groups (e.g., o-, m-, and p-chlorophenyl, -(CH)-N(R 6 )C(O)NR 6 2, -(CH2) n -C(O)NR 6 2. -(CH2)oC(O)R 6 , -(CH2) o -C(O)OR 6 , -(CH2) o -C(O)NR 6 2. -(CH2)-C(O)-(CH2) p C(O)CH3, -(CH2)-O-CO-R6, -(CH2)-NR 6 -(CH2) p -NR 6 2, -(CH2) o -O-(CH2) p CH(OH)CH2OH, -(CH2) o (OCH2CH2) p OR 6 , -(CH2) o -SO2-Ph, and -(CH2) o -O-C6F5). 6 and phenyl group is as defined above, and o and p are integers ranging from 0 to 10, which may be the same or different.

[0021] In formula (I), a divalent R having Si bonds at both ends 4 Examples of groups include the monovalent R 4 Examples of groups include those derived from the above groups, where an additional bond is formed by replacing a hydrogen atom. Examples of such groups are -(CH2)-, -CH(CH3)-, -C(CH3)2-, -CH(CH3)-CH2-, -CH4-, -CH(Ph)-CH2-, -C(CF3)2-, -(CH2) o -C6H4-(CH2) o -, -(CH2) o -C6H4-C6H4-(CH2) o -, -(CHO) p, (CH2CH2O) o , -(CH2) o -O x -C6H4-SO2-C6H4-O x -(CH2) o -, where x is 0 or 1, and Ph, o and p are as defined above.

[0022] R 4 The group is preferably a monovalent Si-C bonded, optionally substituted hydrocarbon group, containing no aliphatic carbon-carbon multiple bonds, and desirably has 1 to 18 carbon atoms. Particularly preferred is a monovalent Si-C bonded hydrocarbon group containing no aliphatic carbon-carbon multiple bonds and having 1 to 6 carbon atoms, particularly a methyl group or a phenyl group.

[0023] R in formula (I) 5 The R group is any group that exhibits strong reactivity toward addition reactions (hydrosilylation reactions) with compounds that contain SiH functional groups. 5 When the group is a hydrocarbon substituent having a Si-C bond, preferred substitutions are halogen atoms, cyano groups, and -OR 6 and this R 6 follows the definition above.

[0024] R 5 The groups are preferably alkenyl groups and alkynyl groups having 2 to 6 carbon atoms, such as vinyl, allyl, methallyl, 1-propynyl, 5-hexynyl, ethynyl, butadienyl, hexadienyl, cyclopentadienyl, cyclohexenyl, vinylcyclohexylethyl, divinylcyclohexylethyl, norbornyl, vinylphenyl, and styryl groups, with vinyl, allyl, and hexynyl being particularly preferred.

[0025] The molecular weight of component (A) can vary widely, e.g., 10 2 ~10 6For example, component (A) may be a relatively low molecular weight oligosiloxane with alkenyl functionality, such as 1,2-divinyltetramethyldisiloxane, or a high molecular weight polydimethylsiloxane (e.g., 10 5 The molecular structure of the molecules forming component (A) is not fixed in any way, and in particular the relatively high molecular weight siloxanes, i.e., oligomeric or polymeric SiH-containing siloxanes, may be linear, cyclic, branched, or otherwise resinous or network-like in structure. Linear or cyclic polysiloxanes may be those having a molecular weight of R 4 3SiO 1 / 2 , R 5 R 4 2SiO 1 / 2 , R 5 R 4 SiO 1 / 2 , and R 4 2SiO 2 / 2 units (wherein R 4 R 5 Preferably, the branched or network polysiloxane is composed of trifunctional and / or tetrafunctional units, and the polysiloxane has the formula R 4 SiO 3 / 2 , R 5 SiO 3 / 2 , and SiO 4 / 2 Of course, it is possible to use a variety of siloxane mixtures that meet the requirements of component (A).

[0026] In particular, component (A) is preferably a substantially linear copolymer having a vinyl functional group and a viscosity in the range of 0.1 to 800,000 mPa·s, particularly preferably 0.1 to 200,000 mPa·s (in both cases, a viscosity of 0.1 s is measured using a cone-plate rotational viscometer calibrated in accordance with DIN EN ISO 3219:1994 and DIN 53019 (opening angle of 2° and 0.1 s is measured). -1Preferably, polydiorganosiloxanes having a shear rate of 0.15 MPa (measured at 25° C. using a CP50-2 cone plate) are used.

[0027] Ingredient (B) The organosilicone compound (B) used can be any organosilicone compound having a hydrogen functional group that has been used up to now in addition-crosslinkable compositions. The organopolysiloxane (B) having Si-bonded hydrogen atoms used is preferably a linear, cyclic, or branched organopolysiloxane composed of units of general formula (III). R 4 c H d SiO (4-c-d) / 2 (III) (In the formula, R 4 is defined as above, c is 0, 1, 2, or 3; d is 0, 1, or 2, However, the sum of c + d is 3 or less, and there are at least two silicon-bonded hydrogen atoms per molecule.

[0028] The organosiloxane (B) used in the present invention preferably contains silicon-bonded hydrogen atoms in the range of 0.04 to 1.7 mass % based on the total molecular weight. The molecular weight of component (B) also varies widely, for example, from 10 2 ~10 6 g / mol. Thus, component (B) may be, for example, a relatively low molecular weight SiH-functional oligosiloxane (e.g., tetramethyldisiloxane), a high molecular weight polymeric polydimethylsiloxane having SiH groups in the main chain or terminal positions, or a silicone resin having SiH groups.

[0029] The structures of the molecules forming component (B) are not fixed in any way, and in particular the relatively high molecular weight SiH-containing siloxanes (i.e., oligomeric or polymeric SiH-containing siloxanes) may be linear, cyclic, branched, or otherwise resinous or network-like in structure. Linear and cyclic polysiloxanes (B) are represented by the formula R 4 3SiO 1 / 2 , H.R. 4 2SiO 1 / 2 , HR4SiO 2 / 2 , and R 4 2SiO 2 / 2 , units (wherein R 4 The branched or network polysiloxane is preferably composed of trifunctional and / or tetrafunctional units, with R 4 SiO 3 / 2 , HSiO 3 / 2 , and SiO 4 / 2 (In the formula, R 4 is preferably composed of (again as defined above).

[0030] Of course, various siloxane mixtures that satisfy the requirements of component (B) can be used. In particular, the molecules that form component (B) must contain SiH groups, and aliphatic unsaturated groups may also be used if necessary. In particular, compounds with low molecular weight SiH functional groups (e.g., tetrakis(dimethylsiloxy)silane and tetramethylcyclotetrasiloxane) and viscosities in the range of 10 to 200,000 mPa·s (viscosity is measured using a cone-plate rotational viscometer calibrated in accordance with DIN EN ISO 3219:1994 or DIN 53019 (opening angle 2° = 0.1 s)) are preferred. -1 It is desirable to use relatively high molecular weight siloxanes (e.g., methylhydrogenpolysiloxane and dimethylhydrogenmethylpolysiloxane) having SiH functional groups with a shear rate of 100 MPa (measured at 25°C using a CP50-2 cone-plate with a shear rate of 100 MPa), or similar compounds having SiH groups in which some of the methyl groups have been replaced with 3,3,3-trifluoropropyl or phenyl groups.

[0031] In the crosslinkable silicone composition of the present invention, component (B) preferably has a molar ratio of SiH groups to aliphatic unsaturated groups in component (A) in the range of 0.1 to 20, and more preferably 0.3 to 2.0.

[0032] The components (A) and (B) used according to the invention are commercially available products or can be prepared by standard processes.

[0033] The silicone composition of the present invention may be comprised of an organopolysiloxane (C) having both an aliphatic carbon-carbon multiple bond and a silicon-bonded hydrogen atom, instead of components (A) and (B). The silicone composition of the present invention may contain all three of components (A), (B), and (C).

[0034] Ingredients (C) When siloxane (C) is used, it is preferably a compound composed of units of the following general formulae (IV), (V), and (VI). R 4 f SiO 4 / 2 (IV) R 4 g R 5 SiO 3-g / 2 (V) R 4 h HSiO 3-h / 2 (VI) (In the formula, R 4 or R 5 is defined as above, f is 0, 1, 2, or 3; g is 0, 1, or 2; h is 0, 1, or 2, However, there must be at least two R 5 provided that there are present a group and at least two Si-bonded hydrogen atoms.

[0035] Examples of organosiloxane (C) include SiO 4 / 2 , R 4 3SiO1 / 2 , R 4 2nd Round 5 SiO 1 / 2 , and R 4 2HSiO 1 / 2 These resins are made up of R 4 SiO 3 / 2 , and R 4 2SiO units, and linear organopolysiloxanes are basically R 4 2nd Round 5 SiO 1 / 2 , R 4 2SiO, and R 4 HSiO unit (wherein R 4 or R 5 is defined above).

[0036] The organopolysiloxane (C) preferably has an average viscosity in the range of 0.01 to 800,000 Pa·s, particularly preferably 0.1 to 200,000 Pa·s (in either case, measured using a cone-plate rotational viscometer calibrated in accordance with DIN EN ISO 3219:1994 or DIN 53019 (opening angle of 2° = 0.1 s)). -1 It is desirable to have a shear rate of 0.01 MPa (measured at 25°C using a CP50-2 cone-plate).

[0037] Organosiloxanes (C) are commercially available products or can be prepared by standard processes.

[0038] The addition-crosslinking silicone elastomer (ii) according to the present invention typically contains 30 to 95 mass %, preferably 30 to 80 mass %, and particularly preferably 35 to 70 mass % of component (A) relative to the total mass of the addition-crosslinking silicone elastomer composition (ii).

[0039] The addition-crosslinking silicone elastomer (ii) according to the present invention typically contains 0.1 to 60 mass %, preferably 0.5 to 50 mass %, particularly preferably 1 to 40 mass % of component (B) relative to the total mass of the addition-crosslinking silicone elastomer composition (ii).

[0040] When the addition-crosslinking silicone elastomer (ii) according to the present invention contains component (C), the content of component (C) is usually 30 to 95 mass %, preferably 30 to 80 mass %, and particularly preferably 40 to 70 mass %, based on the total mass of the addition-crosslinking silicone elastomer composition (ii).

[0041] Ingredients (D) The hydrosilylation catalyst (D) used can be any catalyst known in the prior art. Component (D) can be, for example, a platinum group element such as platinum, rhodium, ruthenium, palladium, osmium, or iridium; an organometallic compound; or a combination thereof. Examples of component (D) include hexachloroplatinic acid (IV), platinum (II) dichloride, platinum (II) acetylacetonate, and complexes encapsulated in a matrix or core-shell structure. Platinum complexes with low molecular weight organopolysiloxanes include complexes of platinum with 1,3-diethyl-1,1,3,3-tetramethyldisiloxane. Further examples include platinum phosphate complexes, platinum phosphine complexes, or alkylplatinum complexes. These compounds may also be encapsulated in a resin matrix. Suitable hydrosilylation catalysts (D) include those activated by electromagnetic radiation (UV, UV-VIS, IR). Such catalysts have also been known for a long time in the prior art and include (η-diolefin)(σ-aryl)platinum complexes (described, for example, in U.S. Pat. No. 6,046,250 A, corresponding to EP 0,561,919 B1), β-diketonate platinum(II) complexes (described, for example, in Canadian Patent No. 2,014,996, corresponding to EP 0,398,701 B1), and (η 5 -cyclopentadienyl)tri(σ-alkyl)platinum(IV) complexes (for example, as described in U.S. Pat. No. 6,376,569 B1, which corresponds to European Patent No. 0,561,893 B1), trimethyl(methylcyclopentadienyl)platinum(IV), and complexes obtained by substituting a group that coordinates to platinum (for example, as described in European Patent No. 6,127,446 A, which corresponds to European Patent No. 1,803,728 B01).

[0042] The concentration of component (D) in addition-crosslinking silicone elastomer (ii) is sufficient to generate the heat required to catalyze the hydrosilylation reaction that occurs upon contact of components (A) and (B). The content of component (D) may be in the range of 0.1 to 1,000 ppm, 0.5 to 100 ppm, or 1 to 50 ppm of platinum group metal, based on the total mass of the components. If the platinum group metal content is less than 1 ppm, the cure rate may be slow. Using more than 100 ppm of platinum group metal may be uneconomical or may reduce the stability of the adhesive.

[0043] In the case of two-component systems, it is preferable to use Karstedt's catalyst (platinum-1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex), and in the case of one-component systems, it is preferable to use platinum phosphate complexes (for example, as described in US Patent No. 2009088524A, which corresponds to EP Patent No. 2050768A1).

[0044] Ingredient (E) Component (E) comprises pyrogenic or precipitated silica or a resinous, i.e., three-dimensionally crosslinked, polyorganosiloxane distinct from (A), (B), and (C). 2 / g~400m 2 Reinforcing fillers such as pyrogenic and precipitated silicas with BET specific surface areas in the range of 100 m 2 / g~300m 2 Pyrogenic and precipitated silicas having a BET specific surface area in the range of 1 / g are particularly preferred. These silica fillers may be hydrophilic or may be hydrophobized by known methods. It is preferable to use surface-treated silica (E). This surface treatment is achieved by processes known in the prior art for hydrophobizing fine fillers.

[0045] As a result of the surface treatment, preferred fillers (E) have a carbon content of at least 0.01% by mass and at most 20% by mass, preferably 0.1 to 10% by mass, and particularly preferably 0.5 to 5% by mass. The filler (E) particularly preferably employed in the crosslinkable addition-crosslinking silicone elastomer composition (ii) is surface-treated silica, containing 0.01 to 2% by mass of Si-bonded aliphatic unsaturated groups. Examples of such Si-bonded unsaturated groups include Si-bonded vinyl groups. The three-dimensional cross-linked polyorganosiloxane that is preferable as component (E) and is clearly distinguished from (A), (B), and (C) is a so-called organosiloxane resin, and is composed of units of the general formulae (VII), (VIII), (IX), and (X). R 3 SiO 1 / 2 M Unit (VII), R 2 SiO 2 / 2 D Unit (VIII), RSiO 3 / 2 T Unit (IX), SiO 4 / 2 Q unit (X), In the formula, R is R 1 , R 2 , OH, or OR 2 The units are selected from the following, provided that a minimum of 20 mol% of each unit is selected from units of general formulae (IX) and (X), and that the maximum amount of OH groups among the R groups is 2 mass%.

[0046] R 1 are the same or different and are selected from monovalent hydrocarbon groups having a hydroxyl group, unsaturated hydrocarbon groups, or hydrogen atoms. 1 The group is bonded to the silicon atom through a carbon atom, and the hydrogen atom is bonded directly to the silicon atom. R 2 are the same or independently selected from different monovalent hydrocarbon residues (alkyl, aryl, aralkyl). R 2Examples of unsubstituted groups include alkyl groups (e.g., methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tertiary butyl, n-pentyl, isopentyl, neopentyl, tertiary pentyl, hexyl, n-hexyl, heptyl, n-heptyl, octyl, n-octyl, isooctyl, 2,2,4-trimethylpentyl, nonyl, n-nonyl, and decyl), alkenyl groups (e.g., vinyl, allyl, n-5- Examples of R include cycloalkyl groups (e.g., cyclopentyl, cyclohexyl, 4-ethylcyclohexyl, cycloheptyl, norbornyl, and methylcyclohexyl), aryl groups (e.g., phenyl, biphenylyl, and naphthyl), alkaryl groups (e.g., o-, m-, and p-tolyl groups and ethylphenyl), and aralkyl groups (e.g., benzyl, and α- and β-phenylethyl groups). 2 Divalent hydrocarbon groups of the group include halogenated hydrocarbons (for example, chloromethyl, 3-chloropropyl, 3-bromopropyl, 3,3,3-trifluoropropyl, and 5,5,5,4,4,3,3-heptafluoropentyl groups, chlorophenyl, dichlorophenyl, and trifluorotolyl groups).

[0047] R 2 Preferably, the group contains 1 to 6 carbon atoms, and is particularly preferably methyl or phenyl. Preferred R groups are methyl, ethyl, phenyl, and vinyl.

[0048] These organosiloxane resins (E) preferably contain at least 30 mol %, in particular at least 40 mol %, and preferably at most 80 mol %, in particular at most 70 mol %, of units of general formulae (IX) and (X).

[0049] These organosiloxane resins (E) are preferably MQ resins (MQ) containing at least 80 mol %, preferably at least 95 mol %, particularly preferably at least 97 mol % of units of formula (VII) and (X). The average ratio of units of general formula (VII) and (X) is preferably at least 0.25, particularly at least 0.5, and at most 2, particularly at most 1.5.

[0050] It is desirable to substitute up to 1% by weight, particularly preferably up to 0.5% by weight, of the R groups with OH.

[0051] Of the R groups, at least 0.01 mol %, particularly preferably at least 0.05 mol %, and at most 8 mol %, particularly preferably at most 5 mol % are R 1 It is preferable to replace it with

[0052] It is desirable for the organosiloxane resin (E) to have a number average molecular weight Mn of at least 200 g / mol, in particular at least 1,000 g / mol, and at most 100,000 g / mol, in particular at most 20,000 g / mol.

[0053] In the addition-crosslinking silicone composition (ii) of the present invention, it is desirable to use various fillers or a mixture of two or more types of fine fillers as component (E). The addition-crosslinking silicone elastomer composition (ii) according to the present invention contains 0 to 45 mass %, and particularly preferably 0 to 35 mass %, of component (E).

[0054] The addition-crosslinking silicone composition of the present invention can optionally contain additives known to those skilled in the art from the background art of addition-crosslinking compositions, such as, for example, rheological additives, reaction inhibitors, light stabilizers, flame retardants, dispersants, heat stabilizers, etc.

[0055] For clarity, it should be noted that the amounts of each component of silicone composition (ii) used are always selected to add up to 100% by weight.

[0056] Ingredient (iii) Component (iii) is clearly distinguishable from (A), (B), (C), and (E) and is stable at 25°C for 0.1 s. -1 It is a polysiloxane that has a viscosity of 5,000,000 mPa·s or more measured at a shear rate of 1000 / 2000 / 2000.

[0057] The polysiloxane in component (iii) has a mostly linear structure with only a small amount of branching. When branching is present, the content of T and Q units is 500 ppm or less. Such polysiloxanes have long been known to those skilled in the art. The T units are represented by the general formula (IX) above, and the Q units are represented by the general formula (X) above.

[0058] The polysiloxane of component (iii) is preferably composed of a polysiloxane compound comprising units of general formula (XI). R 7 m R 8 n SiO (4-m-n) / 2 (XI) (In the formula, R 7 are each independently the same or different organic or inorganic group having no aliphatic carbon-carbon multiple bond, R 8 are each independently the same or different monovalent substituted or unsubstituted Si-C bonded hydrocarbon groups having at least one aliphatic carbon-carbon multiple bond, m is 0, 1, 2, or 3; n is 0, 1, or 2, However, the sum of m and n must be 3 or less.) R 7 is preferably alkyl or aryl, and particularly preferably methyl or phenyl. R 8 If there is R 8 Preferably, the vinyl groups are vinyl groups. The vinyl groups may be terminal or present in the backbone of the polysiloxane. It is preferred that linear polysiloxane (iii) predominates. Particularly preferred is that linear polysiloxane (iii) has vinyl groups at both ends (MVi unit), and the main chain of polysiloxane (D Vi The dominant structure is the structure of the individual (as a unit). Polysiloxane (iii) is also completely R 8 may not include.

[0059] Component (iii) has a vinyl group content of 0 to 20 mol %, preferably 0 to 2 mol %.

[0060] One type of (iii) or a mixture of two or more types of (iii) may be used. The electrospinning solution according to the present invention contains 1 to 40% by mass, particularly preferably 1 to 25% by mass, of solution (iii).

[0061] For clarity, it should be noted that the amounts of components (i), (ii), and (iii) used in the electrospinning solution according to the present invention are always selected so that they add up to 100% by weight.

[0062] The present invention further provides a method for producing a nonwoven fabric, comprising: In a first step, all components are mixed together to obtain an electrospinning solution according to the present invention in the form of a solution; In the second step, a nonwoven fabric made of pure silicone elastomer fibers is produced from this mixed solution by electrospinning. In a third step the fibers can be hardened either by heat or electromagnetic radiation.

[0063] Depending on the embodiment, the first step (preparing the electrospinning solution) can be timed or can occur immediately before the second step (performing electrospinning). The preparation of the electrospinning solution in the first step may be carried out in multiple steps. Components (i), (ii), and (iii) can be mixed in any order and combination. Thus, components (ii) and (iii) may be partially or completely dissolved in (i) simultaneously or separately, and the two precursor solutions may be mixed to form a single solution. However, the components of silicone elastomer composition (ii) may also be mixed separately as (iii) and (i), particularly including two-component silicones that often do not contain all of components (A), (B), and (D). For the electrospinning solution, this means that, for example, components (A), (D), and some of (E) may be mixed with (iii) and (i) in one or more steps, and then component (B) and the remaining component (E) may be mixed with (iii) and (i) separately in one or more steps. If silicone composition (ii) contains component (E), i.e., a filler, it may be advantageous to first disperse the filler in at least some of the components of (ii) or in (iii). One or more components in (ii) preferably influence the dispersion of this filler. This dispersion step is preferably carried out using a high-speed mixer (=dissolver), and preferably a scraper is used to ensure a uniform distribution of the filler. A planetary dissolver with a scraper is preferably used. Dissolver disks can be used with any number or arrangement of teeth. Suitable mixing devices for dissolving any of the components (ii) or (iii) in the solvent (i) include any type of mixing device such as a magnetic stirrer, a KPG stirrer, a centrifugal mixer, a planetary mixer, a high speed mixer, etc.

[0064] In the second step, the process of electrospinning of a solution is known in the background art and is described in detail, for example, in WO2014114501.

[0065] In the third step, the fibers are preferably crosslinked by heat, preferably at 30°C to 250°C, preferably at least 50°C, particularly preferably at least 100°C, and 120 to 210°C. Thermal curing is carried out, for example, using a heat treatment device or oven that irradiates infrared rays with wavelengths of 780 nm to 1 mm. When a UV-activated hydrosilylation catalyst (D) is used, crosslinking is carried out by irradiation with light with a wavelength of 230 to 400 nm for a minimum of 1 second, particularly preferably a minimum of 5 seconds, a maximum of 500 seconds, and particularly preferably a maximum of 240 seconds. When an IR-activated hydrosilylation catalyst (D) is used, crosslinking is similarly carried out by irradiation with infrared rays with wavelengths of 780 nm to 1 mm. When the fibers are crosslinked by photoinitiator, they are preferably irradiated for a minimum of 1 second, particularly preferably a minimum of 5 seconds, and preferably for a maximum of 500 seconds, particularly preferably for a maximum of 240 seconds. Photoinitiator crosslinking is carried out under a protective atmosphere, for example N2 or argon, or in air. After the light and heat irradiation, the fibers are heat-treated as needed for up to 1 hour, preferably up to 10 minutes, and particularly preferably up to 1 minute to harden them. Crosslinking is particularly preferably carried out by UV irradiation, especially at 254 nm.

[0066] The present invention provides a crosslinked nonwoven fabric produced by the method according to the present invention.

[0067] The invention further provides for the use of the nonwoven fabric in coatings on three-dimensional articles, or in bandages, packaging materials, and filters and membranes.

[0068] The nonwoven fabrics according to the present invention are suitable for coating materials that change the surface properties of three-dimensional objects, for example, with respect to soundproofing, heat insulation, or shock absorption. Furthermore, breathability, if desired, may also be achieved by coating materials. It is desirable to use the nonwoven fabrics according to the present invention to coat or laminate housing, building materials, or textile products.

[0069] Furthermore, the nonwoven fabric of the present invention is also preferably used in adhesive bandages. The nonwoven fabric according to the present invention may also be used as a bacterial repellent and / or antibacterial coating. Similarly, the nonwoven fabrics according to the invention are also suitable for use as packaging materials, particularly for packaging food products. The nonwoven fabrics according to the invention are also suitable as coatings for containers for storing liquids, allowing the contents to be completely emptied from the container. The nonwoven fabric according to the invention can likewise be particularly preferably used for clothing, such as jackets, gloves, hats, shoes, or as roofing material. The nonwoven fabric is water-repellent and breathable. The nonwoven fabrics according to the invention can also be particularly advantageously used as filter media, for example in air filters or for separating particles from gas or liquid streams, and in particular in respiratory masks, such as FFP3 and FFP2 masks. The nonwoven fabric according to the present invention can be used as a membrane for separating mixtures, such as reverse osmosis membranes, gas separation membranes, pervaporation, nanofiltration, ultrafiltration, and microfiltration. It is possible to separate solid-solid, gas-gas, solid-gas, and liquid-gas mixtures, particularly liquid-liquid, solid-gas, and liquid-gas mixtures. When the nonwoven fabric according to the present invention is used as a membrane, it can be assembled into a commonly used module, such as a hollow fiber module, a spiral-wound module, a plate module, a cross-flow module, or a dead-end module. The nonwoven fabric of the present invention can be used as a carrier or support layer for other membranes as well. [Example]

[0070] The following examples describe the practice of the present invention according to principles, but are not limited to those explicitly stated. In the following examples, all numbers and percentages are by weight unless otherwise specified. Unless otherwise specified, the following examples are carried out at atmospheric pressure, i.e., 1,000 hPa, and at room temperature, i.e., 25°C, or the temperature reached by combining the reactants without heating or cooling.

[0071] Starting materials Vinyl polymer (iii) used: Contains 0.1 mol% vinyl groups, 25°C, 0.1 s -1 A dimethylvinylsiloxy-terminated dimethylsiloxane methylvinylsiloxane copolymer with a viscosity of 30,000,000 mPa·s measured at a shear rate of 100°C. The molecular weight (Mw) (weight average molecular weight measured by GPC) is 600,000 g / mol.

[0072] Addition crosslinking type silicone elastomer composition (ii) used: As silicone composition 1, a UV-crosslinkable silicone elastic composition was produced according to Example 6 of US Patent No. 2018208797A (corresponding to WO 2017 / 089496A1).

[0073] As silicone composition 2, a thermally crosslinkable silicone composition was prepared according to Example 6 of US Patent No. 2018208797A (corresponding to WO 2017 / 089496A1), except that instead of the UV-active platinum catalyst listed, a platinum complex bearing a thermally activated phosphine ligand suitable for a one-component system, as described in US Patent No. 2009088524A (corresponding to EP 2050768B1), was used.

[0074] As silicone composition 3, the two-component thermally crosslinkable silicone elastomer LUMISIL® LR7601 / 60 obtained from Wacker Chemie AG was used.

[0075] Solvent used (i): n-Butyl acetate (acetic acid n-butyl ester) Chloroform

[0076] Viscosity measurement Viscosity measurements were performed at 25°C using an Anton Paar MCR302 rheometer with an air bearing. A cone / plate system (25 mm, 2°) with a gap size of 105 μm was used. A spatula was used at a gap distance of 115 μm to remove any excess material. The cone was then moved to the 105 μm gap to completely fill the gap. Before each measurement, a "pre-shear" was performed to remove any shear traces from sample preparation, fitting, and trimming. The pre-shear was 60 s with a shear rate of 0.1 s -1 The shear viscosity was measured using a step profile, which was performed for 100 seconds in each case, followed by a 300 second rest period. -1 ~1s -1 The shear viscosity is measured at a constant shear rate of 100 psi. Readings are recorded every 10 seconds, yielding 10 measurement points for each shear rate. The average of these 10 measurement points is the shear viscosity at each shear rate.

[0077] Exemplary Examples Example 1 Preparation of Solution 1 30 g of Silicone Composition 1 was dissolved in 60 g of n-butyl acetate, followed by the addition of 10 g of vinyl polymer and dissolution.

[0078] Example 2 Preparation of Solution 2 30 g of Silicone Composition 2 was dissolved in 60 g of n-butyl acetate, followed by the addition of 10 g of vinyl polymer and dissolution.

[0079] Example 3 Preparation of Solution 3 30 g of the component of the elastomer LUMSIL® LR7601 / 60A was dissolved in 60 g of n-butyl acetate. 10 g of vinyl polymer was then added and dissolved. 30 g of component B of the elastomer LUMSIL® LR7601 / 60B was then dissolved in 60 g of n-butyl acetate, followed by the addition of 10 g of vinyl polymer. The two components were mixed in a 1:1 ratio and immediately used as an electrospinning solution.

[0080] Example 4 Preparation of Solution 4 30 g of Silicone Composition 2 was dissolved in 62 g of n-butyl acetate, followed by the addition and dissolution of 8.0 g of vinyl polymer.

[0081] Example 5 Preparation of Solution 5 30 g of Silicone Composition 2 was dissolved in 55 g of n-butyl acetate, followed by the addition of 15 g of vinyl polymer and dissolution.

[0082] Example 6 Preparation of Solution 6 20 g of Silicone Composition 2 was dissolved in 76 g of n-butyl acetate, followed by the addition of 4.0 g of vinyl polymer and dissolution.

[0083] Example 7 Preparation of Solution 7 30 g of Silicone Composition 2 was dissolved in 70 g of n-butyl acetate.

[0084] Electrospinning The electrospinning process was carried out following International Patent No. 2014114501. To achieve the objectives, the corresponding electrospinning solutions 1 to 7 were electrospun in an electrospinning apparatus under the following conditions: Voltage: DC 22.5kV Distance from drain to electrode: 40cm Cannula diameter: 1mm Flow rate: 5mL / h The substrate used was aluminum foil. The electrodes were either stationary or rotated using an electric motor. After the electrospinning process was completed, the samples composed of the deposited silicone material and aluminum foil were subjected to a photochemical treatment using UV light or a thermal treatment. If silicone composition 2 or 3 (solutions 2-7) was used, the sample was cured in an oven at 150°C for 20 minutes. If silicone composition 1 (solution 1) was used, the sample was exposed to a mercury lamp for 10 minutes.

[0085] Electrospinning of solutions 1 to 6 according to the invention made it possible to obtain fibrous nonwovens composed of fibers in the submicron range. The diameter of the obtained fibers was measured by scanning electron microscopy.

[0086] Electrospinning with solution 7 (non-progressive) fails to yield fibers.

[0087] Table 1 summarizes the composition of each example and the electrospinning results.

[0088] [Table 1]

Claims

1. (i) at least one organic solvent; (ii) (A) at least one organopolysiloxane compound containing a group having an aliphatic carbon-carbon multiple bond; (B) at least one organopolysiloxane compound having a Si-bonded hydrogen atom, or instead of or in addition to (A) and (B), (C) at least one organopolysiloxane compound containing a Si-C bonded group having a group having an aliphatic carbon-carbon multiple bond and a Si-bonded hydrogen atom; (However, all of the above (A), (B) and (C) are performed at 25°C for 0.1 seconds. －１ The viscosity measured at a shear rate of 800,000 mPa·s or less. (D) at least one hydrosilylation catalyst; (E) no filler or at least one silicone-containing filler; an addition-crosslinking silicone elastomer comprising (iii) 25°C, 0.1s －１ at least one polysiloxane other than (A), (B), (C), and (E), having a viscosity of more than 5,000,000 mPa·s measured at a shear rate of 1. An electrospinning solution comprising:

2. 2. The electrospinning solution according to claim 1, wherein the content of the (i) organic solvent is 30 to 98 mass %.

3. 2. The electrospinning solution according to claim 1, wherein the content of the (i) organic solvent is 50 to 95% by mass.

4. The electrospinning solution according to any one of claims 1 to 3, wherein the content of the (iii) polysiloxane is 1 to 40 mass%.

5. 1. A method for producing a nonwoven fabric, comprising: First, in a first step, all of the components according to any one of claims 1 to 4 are mixed to prepare an electrospinning solution according to the present invention in the form of a solution; In a second step, a nonwoven fabric is produced from fibers of the pure silicone elastomer composition produced from the solution by electrospinning.

6. The method of claim 5 wherein the fibers are cured in a third step.

7. 7. The method of claim 5, wherein the curing is carried out by heat or electromagnetic radiation.

8. A hardened nonwoven fabric produced by the method of claim 6 or 7.

9. 10. Use of the nonwoven fabric of claim 8 as a coating for three-dimensional articles or in bandages, packaging materials, and filters and membranes.

10. Use of the nonwoven fabric of claim 8 in filters and membranes.

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