Electrospinned silicone elastomer nonwoven fabric

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] This invention relates to an electrospinning solution based on a silicone elastomer, and to the use of the electrospinning solution in the production of nonwoven fabrics by electrospinning. [Background technology]

[0002] Electrospinning is a known conventional technique for manufacturing nonwoven fabrics, allowing for the adjustment of fiber diameters from several micrometers to several nanometers. This technique involves applying a strong voltage (approximately 10-15 kV) between a spinning nozzle (capillary) and a collector to spin polymer dissolves, solutions, and dispersions into fine fibers of less than a micrometer in diameter, which are then assembled into a fibrous nonwoven fabric. This method allows for increased processing capacity simply by adding more nozzles. Further details on 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 diversity of polymer species already used in electrospinning processes. Electrospinning typically uses thermoplastic resins either molten or dissolved in a suitable solvent.

[0003] Nonwoven fabrics produced by electrospun yarn are used, for example, in filtration, medical masks for industrial and infection control, and air purifiers in which contaminated air is drawn in through an intake and passed through a series of filters by a blower. Fiber nonwoven fabrics with fiber diameters ranging from a few micrometers to a few nanometers exhibit low pressure loss and high filtration efficiency, making them particularly suitable for filter media. Filtration is based on the high specific surface area and low pressure loss of nanofibers, and therefore, exhalation resistance is kept low by the high porosity of the corresponding fiber nonwoven fabric. It is known that electrets are used to increase the filtration efficiency of air and respiratory filters. Electrets are dielectrics that permanently maintain an electric field. This property enhances the ability of the filter material to attract and retain particles such as dust, contaminants, and fibers in the air. This is usually achieved by using fluorinated polymers such as PTEE, because these materials have a strong tendency to charge and retain negative charges (the negative side of the triboelectric series). Electrospinning is suitable for producing nanofibers with electret properties because it directly charges nonwoven fabrics using the electric field used. U.S. Patent No. 8801998B (corresponding to European Patent No. 2557206B1) describes, as an example, an electret for filters made from polyurethane fibers produced by electrospinning using PTEE nanoparticles.

[0004] For filter media to be autoclavable or sterilized, it is essential that the filter media has stability to withstand temperature and ionization radiation. Therefore, common plastics such as polyester and polypropylene are not used for these filter media; instead, special high-melting-point thermoplastic resins such as polyimide (PI) and polyetherimide (PEI) are required. The limited melting and dissolving properties of these thermoplastic resins make their use in the spinning process costly and inconvenient. On the other hand, silicone elastomers are systems that can be crosslinked by temperature or ultraviolet light. The main component before crosslinking is generally soluble in most aprotic solvents, and its viscosity usually decreases with shear, allowing for pump transport and thus easy processing. After crosslinking, silicone elastomers exhibit high mechanical flexibility and stability against temperature and radiation. Furthermore, silicones located on the negative side of the triboelectric series exhibit particularly high electron affinity on the material surface, thus easily functioning as electrets.

[0005] Electrospinning of silicones is a known technique and is usually carried out using organic solvents. To form homogeneous fibers during electrospinning, it is necessary to give the spinning solution sufficient viscoelasticity, and it is a known technique to add high molecular weight hydrophilic polymers as thickeners to ensure viscoelasticity. For example, Chinese Patent No. 109868559 discloses the successful electrospinning of a crosslinkable silicone composition (consisting of polymethylhydrosiloxane, (DVi)4, and hexachloroplatinic acid) using ethanol in the presence of polyvinylpyrrolidone (PVP). Silicones are also suitable for coaxial electrospinning processes, in which core-shell structured fibers are obtained by electrospinning silicone with generally hydrophilic and immiscible polymers without prior mixing. The polymer forming the shell acts as the outer frame for fiber formation, while the silicone is present in the core of the electrospun fiber. As an example, Chinese Patent No. 101498057 describes electrospinning of PVP as a water-soluble polymer (shell) and silicone rubber (core). Silicone dissolves in dichloromethane, and PVP dissolves in ethanol. To obtain silicone fibers, the shell polymer is removed in a subsequent washing step. U.S. Patent Application Publication 2014322512 (corresponding to International Publication 2014143866) describes a needleless electrospinning process for producing core-shell fibers of silicone PLGA using a highly fluid silicone elastomer. A drawback of this method is that additional polymers must be removed in a post-electrospinning step to obtain pure silicone fibers. This removal step is typically carried out in a 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 [Overview of the project]

[0008] Therefore, an object of the present invention is to provide a silicone composition that does not have the aforementioned drawbacks of the prior art and can be used in the electrospinning process without additional polymers.

[0009] Surprisingly, the electrospinning solution according to the present invention has been found to achieve the above objective. The solution of the present invention is suitable for use in the electrospinning process for producing nanofiber nonwoven fabrics composed solely of silicone. According to the present invention, it has at least a sufficient molecular weight, and at 25°C, 0.1s -1 Organopolysiloxane(iii) having a viscosity of 5,000,000 mPa·s or higher, as measured at a shear rate, is extremely important because it is expected to have an effect on the outer frame (shell) during fiber formation. Organopolysiloxane(iii) can be incorporated into the network structure of the silicone elastomer, allowing for the introduction of optimal functional groups as needed. By adding organopolysiloxane(iii) to the electrospinning solution, pure silicone fibers are obtained, eliminating the need for subsequent washing steps.

[0010] Therefore, the present invention is (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 Si-bonded hydrogen atoms, or in place of (A) and (B), or in addition to (A) and (B), (C) At least one organopolysiloxane compound comprising a Si-C bond 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 based on 25°C and 0.1s.) -1 The viscosity measured at the shear rate is 800,000 mPa·s or less. (D) At least one hydrosilylation catalyst, (E) No fillers, or at least one silicone-containing filler, Addition crosslinkable silicone elastomers containing, and (iii) 25℃, 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 as measured at the shear rate, The present invention provides an electrospinning solution containing [the specified ingredient]. [Modes for carrying out the invention]

[0011] In describing the present invention, only preferred embodiments of each feature will be described below to avoid an excessive increase in page count. However, those skilled in the art should clearly understand that any combination of different preferred levels of the embodiments of this disclosure is also explicitly disclosed and explicitly desirable.

[0012] Organic solvent (i) As a solution, a single organic solvent or a mixture of various organic solvents can be used. Optimal 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 having 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% by mass of solvent (i), particularly preferably 50 to 95% by mass.

[0014] Addition-crosslinked silicone elastomer composition (ii) Compounds (A), (B), and / or (C) used in the addition-crosslinked silicone elastomer composition (ii) according to the present invention are known to be 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, siloxane (C) having aliphatic unsaturated groups and Si-bonded hydrogen atoms in the aforementioned proportions may be used instead of compounds (A) and (B). A mixture of (A), (B), and (C) having aliphatic unsaturated groups and Si-bonded hydrogen atoms in the aforementioned proportions can also be used.

[0015] Ingredient (A) The silicone composition according to the present invention preferably contains at least one unsaturated organic silicon compound as component (A), and it is possible to use all the aliphatic unsaturated organic silicon compounds that have been used as addition-crosslinkable compositions so far. For example, silicone block polymers having urea segments, silicone block polymers having amide segments and / or imide segments and / or ester amide segments and / or polystyrene segments and / or silylene segments and / or carborane segments, and silicone graft polymers having ether groups can be mentioned.

[0016] The organosilicon compound (A) containing a Si—C bond group having an aliphatic carbon-carbon multiple bond to be used is preferably a linear or branched organopolysiloxane composed of units of 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 without an aliphatic carbon-carbon bond, 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, provided that the sum of a + b is 3 or less, and there are at least two R 5 groups per molecule. )

[0017] R 4 groups are monovalent or polyvalent groups, and examples of polyvalent groups include divalent, trivalent, and tetravalent groups. These may take a structure in which two, three, or four siloxy units of formula (I) are multiply bonded to each other as an example.

[0018] R 4Further examples include the monovalent groups -F, -Cl, -Br, -OR 6 Examples include substituted or unsubstituted hydrocarbon groups (which may be separated by oxygen atoms or -C(O)- groups) with Si-C bonds, -CN, -SCN, -NCO, and Si-C bonds, 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, and -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 -C6F 5 In this case, R 6 Each of these is a monovalent hydrocarbon group having the same or different hydrogen atoms or 1 to 20 carbon atoms independently. 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 group, hexyl group, n-hexyl group, heptyl group, n-heptyl group, octyl group, n-octyl group, isooctyl group, 2,2,4-trimethylpentyl, nonyl group, n-nonyl group, decyl group, n-decyl group, dodecyl group, n-dodecyl) Examples include groups such as the octadecyl group and n-octadecyl group, cyclic alkyl groups (e.g., cyclopentyl, cyclohexal, cycloheptyl, and methylcyclohexyl), aryl groups (e.g., phenyl, naphthyl, anthryl, and phenanthrene), alkaryl groups (e.g., o-, m-, p-tolyl groups, xylyl groups, and ethylphenyl groups), and aralkyl groups (e.g., benzyl groups, and α-, β-phenylethyl groups).

[0020] R 4Examples of substituents include haloalkyl groups (e.g., 3,3,3-trifluoropropyl, n-propyl group, 2,2,2,2',2',2'-hexafluoroisopropyl group, and heptafluoroisopropyl group), haloaryl groups (e.g., o-, m-, p-chlorophenyl group, -(CH2)-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 Ure 6 ,-(CH2) o -SO2-Ph, and -(CH2) o -O-C6F5) is one example. 6 And the phenyl group is defined as described above, and o and p are the same or different integers in the range of 0 to 10.

[0021] In formula (I), divalent R has Si bonds at both ends. 4 An example of the base is the monovalent R mentioned above. 4 Examples of such groups include those derived from the group itself, where additional bonds are formed by the substitution of hydrogen atoms. Examples of such groups include -(CH2)-, -CH(CH3)-, -C(CH3)2-, -CH(CH3)-CH2-, -C6H4-, -CH(Ph)-CH2-, -C(CF3)2-, and -(CH2). o -C6H4-(CH2) o -,-(CH2) o -C6H4-C6H4-(CH2) o -,-(CH2O) p(CH2CH2O) o ,-(CH2) o -O x -C6H4-SO2-C6H4-O x -(CH2) o - is an example, where x is 0 or 1, and Ph, o, and p follow the definitions above.

[0022] R 4 The group is preferably a monovalent Si-C bonded, optionally substituted hydrocarbon group that does not contain aliphatic carbon-carbon multiple bonds, and preferably has 1 to 18 carbon atoms. Particularly preferred is a hydrocarbon group having a monovalent Si-C bond, not containing aliphatic carbon-carbon multiple bonds, and having 1 to 6 carbon atoms, especially a methyl group or a phenyl group.

[0023] R in equation (I) 5 The group is any group that exhibits strong reactivity to addition reactions (hydrosilylation reactions) by compounds having a SiH functional group. 5 When the group is a hydrocarbon substituent having a Si-C bond, preferred substitutions are halogen atoms, cyano groups, and -OR groups. 6 And this R 6 This 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 desirable.

[0025] The molecular weight of component (A) is wide, for example, 10 2 ~10 6The g / mol range may vary. For example, component (A) may be an oligosiloxane having an alkenyl functional group, such as a relatively low molecular weight 1,2-divinyltetramethyldisiloxane, or a high molecular weight polydimethylsiloxane having a vinyl group with Si bonds at the main chain or terminal position (e.g., 10 5 It may have a molecular weight of g / mol (number average measured using NMR). The structure of the molecules forming component (A) is not fixed in any case, and in particular, relatively high molecular weight siloxanes, i.e., oligomers or polymers, siloxanes containing SiH may have linear, cyclic, branched, or other resinous or network-like structures. Linear or cyclic polysiloxanes are 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 The unit (in the formula, R 4 R 5 It is preferable that the polysiloxane is composed of (as defined above). The branched or reticular polysiloxane consists of trifunctional and / or tetrafunctional units, and the polysiloxane is of formula R 4 SiO 3 / 2 , R 5 SiO 3 / 2 , and SiO 4 / 2 It is desirable that the system be composed of the following units. Of course, it is possible to use various siloxane mixtures that satisfy the conditions of component (A).

[0026] In particular, component (A) is a substantially linear viscometer having vinyl functional groups, with a viscosity of 0.1 to 800,000 mPa·s, especially preferably in the range of 0.1 to 200,000 mPa·s (in all cases, a cone-plate rotational viscometer calibrated in accordance with DIN EN ISO3219:1994 and DIN53019 (opening angle 2°, 0.1s) -1It is preferable to use a polydiorganosiloxane having a shear rate shown by a CP50-2 cone plate (used at 25°C).

[0027] Component (B) As the organosilicon compound (B) to be used, it is possible to use all organosilicon compounds having hydrogen functional groups that have been used as addition-crosslinkable compositions so far. The organopolysiloxane (B) having Si-bonded hydrogen atoms to be 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 in accordance with the definition described above, c is 0, 1, 2, or 3, d is 0, 1, or 2, provided that the sum of c + d is 3 or less, and it is a condition that at least two Si-bonded hydrogen atoms are present per one molecule.)

[0028] The organosiloxane (B) to be used according to the present invention preferably contains Si-bonded hydrogen atoms in the range of 0.04 to 1.7% by mass with respect to its total molecular weight. The molecular weight of component (B) can also vary over a wide range, for example, between 10 2 ~10 6 g / mol. Therefore, component (B) may be, for example, an oligosiloxane having a relatively low molecular weight SiH functional group (e.g., tetramethyldisiloxane), a polydimethylsiloxane of a high molecular polymer having an SiH group at the main chain or terminal position, or a silicone resin having an SiH group.

[0029] The structure of the molecules forming component (B) is not fixed in any case. In particular, siloxanes containing SiH of relatively high molecular weight (i.e., oligomeric or polymeric siloxanes containing SiH) may have a linear, cyclic, branched, or other resinous or network-like structure. Linear and cyclic polysiloxanes (B) have the formula R 4 3SiO 1 / 2 , HR 4 2SiO 1 / 2 , HR4SiO 2 / 2 , and R 4 2SiO 2 / 2 , units (where R 4 follows the definition described above). Branched or network-like polysiloxanes are further composed of trifunctional and / or tetrafunctional units and are preferably composed of R 4 SiO 3 / 2 , HSiO 3 / 2 , and SiO 4 / 2 (where R 4 also follows the definition above here).

[0030] Of course, it is possible to use various siloxane mixtures that meet the conditions of component (B). In particular, the molecules forming component (B) must have a SiH group, and an aliphatic unsaturated group may also be used simultaneously as required. In particular, compounds having a low molecular weight SiH functional group (examples include tetrakis(dimethylsiloxy)silane and tetramethylcyclotetrasiloxane), and a siloxane having a relatively high molecular weight SiH functional group having a viscosity in the range of 10 to 200,000 mPa·s (the viscosity is in accordance with DIN EN ISO 3219:1994 and DIN53019, and is measured at 25°C using a calibrated cone-plate type rotational viscometer (CP50-2 cone-plate with an opening angle of 2° and a shear rate of 0.1 s -1 ), examples include methylhydrogenpolysiloxane and dimethylhydrogenmethylpolysiloxane), or a similar compound having a SiH group in which some of the methyl groups are substituted with 3,3,3-trifluoropropyl groups or phenyl groups is preferably used.

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

[0032] The components (A) and (B) used in the present invention are either commercially available products or can be manufactured by standard processes.

[0033] The silicone composition according to the present invention may consist of an organopolysiloxane (C) having both aliphatic carbon-carbon multiple bonds and Si-bonded hydrogen atoms instead of components (A) and (B). The silicone composition according to the present invention may contain all three components (A), (B), and (C).

[0034] Ingredients (C) When using siloxane (C), it is preferable that the compound be composed of units of the following general formulas (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 Ya R 5 According to the definition above, f is 0, 1, 2, or 3. g is 0, 1, or 2. h is 0, 1, or 2, However, at least two R molecules per molecule 5 (This is conditional on the presence of a group and at least two Si-bonded hydrogen atoms.)

[0035] Organosiloxane (C) is, for example, SiO 4 / 2 , R 4 3SiO1 / 2 , R 4 2R 5 SiO 1 / 2 , and R 4 2HSiO 1 / 2 It is composed of units and is known as MQ resin. These resins are R 4 SiO 3 / 2 , and R 4 Consisting of 2SiO units, linear organopolysiloxanes are basically R 4 2R 5 SiO 1 / 2 , R 4 2SiO, and R 4 HSiO unit (wherein R 4 Ya R 5 It consists of (as defined above).

[0036] The organopolysiloxane (C) has an average viscosity preferably in the range of 0.01 to 800,000 Pa·s, and particularly preferably in the range of 0.1 to 200,000 Pa·s (in all cases, measured using a calibrated cone-plate rotational viscometer (opening angle of 2° and 0.1s) in accordance with DIN EN ISO3219:1994 or DIN53019). -1 It is desirable to have a shear rate (measured at 25°C using a CP50-2 cone plate that indicates the shear rate).

[0037] Organosiloxane (C) is either a commercially available product or can be manufactured using standard processes.

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

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

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

[0041] Ingredients (D) All catalysts known in the prior art can be used as the catalyst (D) for the hydrosilylation reaction. Component (D) may be platinum group elements such as platinum, rhodium, ruthenium, palladium, osmium, and iridium, or organometallic compounds, or combinations thereof. Examples of component (D) include hexachloroplatinic acid, 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 and 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. Some suitable hydrosilylation catalysts (D) are activated by electromagnetic radiation (UV, UV-VIS, IR). Such catalysts have also been known for a long time in the prior art, including (η-diolefin)(σ-aryl)platinum complexes (e.g., described in U.S. Patent No. 6046250A, corresponding to European Patent No. 0561919B1), β-diketonate platinum(II) complexes (e.g., described in Canadian Patent Invention No. 2014996, corresponding to European Patent No. 0398701B1), and (η 5 Examples include (-cyclopentazinyl)tri(σ-alkyl)platinum(IV) complexes (for example, described in U.S. Patent No. 6,376,569,B1, corresponding to European Patent No. 0561893,B1), and trimethyl(methylcyclopentadienyl)platinum(IV) and complexes obtained by substituting the group coordinating to platinum (for example, described in European Patent No. 6,127,446,A, corresponding to European Patent No. 1803,728,B01).

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

[0043] For two-component systems, it is preferable to use a Karlstedt catalyst (platinum-1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex). For one-component systems, it is preferable to use a platinum phosphate complex (for example, as described in U.S. Patent No. 2009088524A, corresponding to European Patent No. 2050768A1).

[0044] Ingredient (E) Component (E) contains a polyorganosiloxane distinct from (A), (B), and (C) that is calcined silica, precipitated silica, or a resin-like, i.e., three-dimensionally crosslinked polyorganosiloxane. 50m 2 / g~400m 2 Reinforcing fillers such as calcined silica or precipitated silica with a BET specific surface area in the range of / g are preferred, 100m 2 / g~300m 2 Calcined silica or precipitated silica having a BET specific surface area in the range of / g is particularly preferred. These silica fillers may be hydrophilic or may be hydrophobic by known methods. It is desirable to use surface-treated silica (E). This surface treatment is achieved by processes known in the prior art to hydrophobicize the fine fillers.

[0045] As a result of surface treatment, the preferred filler (E) has a carbon content of a minimum of 0.01% by mass, a maximum of 20% by mass, preferably 0.1 to 10% by mass, and particularly preferably 0.5 to 5% by mass. The filler (E) particularly preferred in the crosslinkable addition-crosslinked silicone elastomer composition (ii) is surface-treated silica containing 0.01 to 2% by mass of Si-bonded aliphatic unsaturated groups. An example of these Si-bonded unsaturated groups is a Si-bonded vinyl group. Clearly distinct from (A), (B), and (C), the desirable three-dimensional crosslinked polyorganosiloxane as component (E) is a so-called organosiloxane resin, composed of units of general formulas (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 selection is made from the following, provided that a minimum of 20 mol% within a single unit is selected from units of general formulas (IX) and (X), and that the OH group among the R groups is a maximum of 2 mass%.

[0046] R 1 R is selected from hydrocarbon groups, unsaturated hydrocarbon groups, or hydrogen atoms having the same or independently different monovalent hydroxyl groups. 1 The group is bonded to the silicon atom via the carbon atom, and the hydrogen atom is directly bonded to the silicon atom. R 2 The residues are selected from the same or independently distinct monovalent hydrocarbon residues (alkyl, aryl, aralkyl). R 2Unsubstituted groups include alkyl groups (e.g., methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tertiary-butyl, n-pentyl, isopentyl, neopentyl, tertiary-pentyl group, hexyl group, n-hexyl group, heptyl group, n-heptyl group, octyl group, n-octyl group, isooctyl group, 2,2,4-trimethylpentyl group, nonyl group, n-nonyl group, and decyl group, n-decyl group), and alkenyl groups (e.g., vinyl, allyl, n-5-hexyl). Examples include xenyl, 4-vinylcyclohexyl, and 3-norbornyl groups, cycloalkyl groups (e.g., cyclopentyl, cyclohexyl, 4-ethylcyclohexyl, cycloheptyl, norbornyl, and methylcyclohexyl groups), aryl groups (e.g., phenyl, biphenylyl, and naphthyl groups), alkali-yl groups (e.g., o-, m-, p-tolyl, and ethylphenyl groups), and aralkyl groups (e.g., benzyl, and α-, β-phenylethyl groups). 2 Examples of divalent hydrocarbon groups 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 It preferably contains 1 to 6 carbon atoms. Methyl or phenyl is particularly desirable. The R group is preferably methyl, ethyl, phenyl, or vinyl.

[0048] These organosiloxane resins (E) preferably contain at least 30 mol%, particularly at least 40 mol%, and preferably up to 80 mol%, particularly up to 70 mol%, of units of general formulas (IX) and (X).

[0049] These organosiloxane resins (E) are preferably MQ resins (MQ) containing a minimum of 80 mol%, preferably a minimum of 95 mol%, and particularly preferably a minimum of 97 mol%, of the units of formulas (VII) and (X). The average ratio of the units of general formulas (VII) and (X) is preferably a minimum of 0.25, particularly a minimum of 0.5, and a maximum of 2, particularly a maximum of 1.5.

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

[0051] Of the R groups, a minimum of 0.01 mol%, particularly preferably a minimum of 0.05 mol%, and a maximum of 8 mol%, particularly preferably a maximum of 5 mol%, are R 1 It is preferable to replace it with this.

[0052] It is desirable that the number-average molecular weight Mn of the organosiloxane resin (E) is at least 200 g / mol, particularly at least 1,000 g / mol, and at most 100,000 g / mol, particularly at most 20,000 g / mol.

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

[0054] The addition-crosslinked silicone composition according to the present invention may optionally contain additives that are well known to those skilled in the art from the background art of addition-crosslinked compositions. Examples of these additives include rheological additives, reaction inhibitors, light stabilizers, flame retardants, dispersants, and heat stabilizers.

[0055] To clarify, it should be noted that the amounts of each component used in silicone composition (ii) are always selected so that their total proportion is always 100% by mass.

[0056] Ingredient (iii) Component (iii) is clearly distinguishable from (A), (B), (C), and (E), at 25°C, 0.1s. -1 This is a polysiloxane that exhibits a viscosity of 5,000,000 mPa·s or higher when measured at a shear rate of .

[0057] The polysiloxane in component (iii) is mostly linear in structure, with only slight 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 unit is the general formula (IX) described above, and the Q unit is the general formula (X) described above.

[0058] The polysiloxane of component (iii) is preferably composed of a polysiloxane compound consisting of units of general formula (XI). R 7 m R 8 n SiO (4-m-n) / 2 (XI) (In the formula, R 7 These are, independently, organic or inorganic groups that do not have the same or different aliphatic carbon-carbon multiple bonds. R 8 Each of these is independently a Si-C bonded hydrocarbon group having at least one identical or different monovalent substituted or unsubstituted aliphatic carbon-carbon multiple bond. m is 0, 1, 2, or 3. n is 0, 1, or 2, However, the sum of m+n must be 3 or less. R 7 Alkyl or aryl compounds are preferred, and methyl and phenyl compounds are particularly preferred. R 8 If R exists, 8 Vinyl groups are preferred. Vinyl groups may be present at the ends or in the main chain of the polysiloxane. It is preferable that linear polysiloxane(iii) is dominant. Particularly preferred is linear polysiloxane(iii) with vinyl groups at both ends (MVi (as a unit), and the main chain of polysiloxane (D Vi The goal is to create a dominant unit. Polysiloxane(iii) is also completely R 8 It may not include this.

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

[0060] A single (iii) or a mixture of two or more (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] To clarify, it should be noted that the amounts of components (i), (ii), and (iii) used in the electrospinning solution according to the present invention are selected so that their total always equals 100% by mass.

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

[0063] Depending on the embodiment, the first step (the step of producing the electrospinning solution) can be performed by adjusting the timing, or immediately before the second step (the step of performing electrospinning). The production 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 dissolved in (i) simultaneously or separately, partially or completely, and the two precursor solutions may be mixed to form a single solution. However, in some cases, the components of the silicone elastomer composition (ii) are mixed separately as (iii) and (i). This also includes two-component silicones, which often do not contain components (A), (B), and (D). Regarding the electrospinning solution, this means that, for example, components (A), (D), and a portion 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 separately with (iii) and (i) in one or more steps. If the 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). It is desirable that one or more components in (ii) affect the dispersion of this filler. This dispersion step is preferably carried out using a high-speed mixer (=dissolver), and it is also desirable to use a scraper to uniformly distribute the filler. It is preferable to use a planetary dissolver with a scraper. The dissolver disc can be used without restrictions on the arrangement or number of teeth. Mixing apparatus suitable for dissolving any component of (ii) or (iii) in solvent (i) includes all kinds of mixing apparatus, such as magnetic stirrers, KPG stirrers, centrifugal mixers, planetary mixers, and high-speed mixers.

[0064] In the second step, the electrospinning of the solution is known in the background art, and details are described, for example, in International Publication No. 2014114501.

[0065] In the third step, crosslinking of the fibers is preferably carried out by heat, preferably at 30°C to 250°C, preferably at a minimum of 50°C, and particularly preferably at a minimum of 100°C and 120°C to 210°C. The heat curing is carried out using a heat treatment apparatus or furnace that irradiates infrared light with a wavelength of 780 nm to 1 mm, for example. When using a UV-activated hydrosilylation catalyst (D), crosslinking is carried out by the emission of light with a wavelength of 230 to 400 nm for a minimum of 1 second, particularly preferably at a minimum of 5 seconds, and particularly preferably at a maximum of 500 seconds, and particularly preferably at a maximum of 240 seconds. When using an IR-activated hydrosilylation catalyst (D), crosslinking is similarly carried out by irradiation with infrared light with a wavelength of 780 nm to 1 mm. When crosslinking fibers with a photopolymerization initiator, the fibers are irradiated with light for a minimum of 1 second, a minimum of 5 seconds, and a maximum of 500 seconds, a maximum of 240 seconds. Crosslinking with the photopolymerization initiator is carried out in a protective atmosphere, for example, with N2 or argon, or in the atmosphere. After light and heat irradiation, the fibers are heat-treated as needed to cure them for a maximum of 1 hour, preferably a maximum of 10 minutes, and especially preferably a maximum of 1 minute. Crosslinking is preferably performed by UV irradiation, with irradiation at 254 nm being particularly desirable.

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

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

[0068] The nonwoven fabric according to the present invention is suitable as a coating material for altering the surface properties of three-dimensional materials, for example, with respect to sound insulation, heat insulation, or shock absorption. Furthermore, if breathability is required, it may also be possible to achieve this through the coating material. It is desirable to use the nonwoven fabric according to the present invention to coat and laminate houses, building materials, or textile products.

[0069] Furthermore, the nonwoven fabric according to the present invention is also preferably used in adhesive bandages. The nonwoven fabric according to the present invention may also be used as a coating material that has bacterial repellency and / or antibacterial properties. Similarly, the nonwoven fabric according to the present invention is also suitable for use as a packaging material, and is particularly suitable for packaging food products. The nonwoven fabric according to the present invention is also suitable as a coating for liquid storage containers, which allows for the complete discharge of the contents from the container. The nonwoven fabric according to the present invention can be used particularly preferably as clothing, such as jackets, gloves, hats, shoes, or roofing material. This nonwoven fabric is water-repellent and breathable. The nonwoven fabric according to the present invention can be particularly preferably used as an air filter or a filter material for separating particles from gaseous or liquid flows. It can also be used as a filter material 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 methods, nanofiltration, ultrafiltration, and microfiltration. It is possible to separate solid-solid, gas-gas, solid-gas, and liquid-gas mixtures, and especially liquid-liquid, solid-gas, and liquid-gas mixtures. When the nonwoven fabric according to the present invention is used as a membrane, it can also be assembled into commonly used modules, such as hollow fiber modules, spiral modules, plate modules, cross-flow modules, or dead-end modules. The nonwoven fabric according to the present invention can also be used as a mediating or supporting layer for other membranes. [Examples]

[0070] The following examples describe methods for carrying out the present invention in principle, but the present invention is not limited to those explicitly stated. In the following examples, unless otherwise specified, all numerical values ​​for numbers and proportions are based on mass. Unless otherwise specified, the following examples are carried out under atmospheric pressure, that is, 1,000 hPa, and at room temperature, i.e., 25°C, or a temperature reached by the combination of reactants without heating or cooling.

[0071] Starting material Vinyl polymer to be used (iii): It contains 0.1 mol% vinyl groups and is tested at 25°C for 0.1 seconds. -1 A dimethylvinylsiloxy-terminated dimethylsiloxane methylvinylsiloxane copolymer exhibiting a viscosity of 30,000,000 mPa·s as measured at a shear rate. Its molecular weight Mw (mass-average molecular weight measured by GPC) is 600,000 g / mol.

[0072] Addition-crosslinked silicone elastomer composition to be used (ii): As Silicone Composition 1, a UV-crosslinkable silicone elastic composition was prepared according to Example 6 of U.S. Patent No. 2018208797A (corresponding to International Publication No. 2017 / 089496A1).

[0073] As silicone composition 2, a thermocrosslinkable silicone composition was prepared according to Example 6 of U.S. Patent No. 2018208797A (corresponding to International Publication No. 2017 / 089496A1). On the other hand, instead of the enumerated UV-activated platinum catalyst, a platinum complex having a thermoactivatable phosphine ligand suitable for a one-component system was used, as described in U.S. Patent No. 2009088524A (corresponding to European Patent No. 2050768B1).

[0074] As silicone composition 3, we used LUMISIL® LR7601 / 60, a two-component thermocrosslinkable silicone elastomer obtained from Wacker Chemie AG.

[0075] Solvent to be used (i): n-butyl acetate (n-butyl acetate ester) Chloroform

[0076] Viscosity measurement Viscosity measurements were performed at 25°C using an Anton Paar MCR302 rheometer with air bearings. A cone / plate system (25 mm, 2°) with a gap size of 105 μm was used. Excess material was removed using a spatula at a gap distance of 115 μm. The cone was then moved to a 105 μm gap to completely fill the gap. Before each measurement, "pre-shearing" was performed to remove any traces of shearing from sample preparation, adaptation, and trimming. Pre-shearing was performed for 60 seconds at a shear rate of 0.1 s. -1 The test was conducted, followed by a 300-second resting period. Shear viscosity was measured using a method called step profiling. This involved 100 seconds and 0.1 seconds for each condition. -1 ~1s -1 This process involves shearing at a constant shear rate. Readings are recorded every 10 seconds, and 10 measurement points are obtained for each shear rate. The average of these 10 measurement points represents 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. Subsequently, 10 g of vinyl polymer was added and dissolved.

[0078] Example 2: Preparation of Solution 2 30 g of silicone composition 2 was dissolved in 60 g of n-butyl acetate. Subsequently, 10 g of vinyl polymer was added and dissolved.

[0079] Example 3: Preparation of Solution 3 30 g of component B of elastomer LUMSIL® LR7601 / 60A was dissolved in 60 g of n-butyl acetate. Subsequently, 10 g of vinyl polymer was added and dissolved. Then, 30 g of component B of elastomer LUMISIL® LR7601 / 60B was dissolved in 60 g of n-butyl acetate, and subsequently, 10 g of vinyl polymer was added and dissolved. Both 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. Subsequently, 8.0 g of vinyl polymer was added and dissolved.

[0081] Example 5: Preparation of Solution 5 30 g of silicone composition 2 was dissolved in 55 g of n-butyl acetate. Subsequently, 15 g of vinyl polymer was added and dissolved.

[0082] Example 6: Preparation of Solution 6 20 g of silicone composition 2 was dissolved in 76 g of n-butyl acetate. Subsequently, 4.0 g of vinyl polymer was added and dissolved.

[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 in accordance with International Patent No. 2014114501. To achieve the objective, the corresponding electrospinning solutions 1 to 7 were electrospinned in an electrospinning apparatus under the following conditions. Voltage: DC 22.5kV Distance from drain pipe to electrode: 40 cm Pipe diameter: 1mm Flow rate: 5mL / h The substrate used is aluminum foil. The electrodes were either stationary or rotated using an electric motor. After the electrospinning process was completed, the sample, consisting of precipitated silicone material and aluminum foil, was subjected to photochemical treatment using UV light or heat treatment. If silicone composition 2 or 3 (solutions 2-7) was used, the sample was cured in a 150°C furnace for 20 minutes. If silicone composition 1 (solution 1) was used, the sample was exposed to mercury light for 10 minutes.

[0085] Electrospinning of solutions 1 to 6 according to the present invention made it possible to obtain a nonwoven fabric composed of submicron-sized fibers. The diameter of the obtained fibers was measured by scanning electron microscopy.

[0086] Electrospinning using solution 7 (non-inventive) cannot yield fibers.

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

[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 Si-bonded hydrogen atoms, or in place of (A) and (B), or in addition to (A) and (B), (C) At least one organopolysiloxane compound comprising a Si-C bond group having an aliphatic carbon-carbon multiple bond and a Si-bonded hydrogen atom, (However, all of the above (A), (B), and (C) are based on 25°C and 0.1s.) －１ The viscosity measured at the shear rate is 800,000 mPa·s or less. (D) At least one hydrosilylation catalyst, (E) Addition-crosslinked silicone elastomers that do not contain fillers or contain at least one silicone-containing filler, and (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 as measured at the shear rate, A electrospinning solution containing the above.

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

3. The electrospinning solution according to claim 1, wherein the content of (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% by mass.

5. A method for manufacturing nonwoven fabric, First, in the first step, all the components described in any one of claims 1 to 3 are mixed to obtain the electrospinning solution according to the present invention in solution form. A method for producing a nonwoven fabric from fibers of a pure silicone elastomer composition produced from the solution by electrospinning, in the second step.

6. The method according to claim 5, wherein the fibers are cured in the third step.

7. The method according to claim 5, wherein the curing is performed by heat or electromagnetic wave irradiation.

8. A cured nonwoven fabric manufactured by the method described in claim 6.

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

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

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