Silicone emulsion composition and method for producing release coating using said composition

Abstract

To provide a silicone emulsion composition for a release coating film, which can be applied thinly and evenly and provides a release coating film with excellent coating appearance; and to provide a method for producing a release coating film using the composition.SOLUTION: A silicone emulsion composition for a release coating film comprises: (A) diorganopolysiloxane that contains an alkenyl group; (B) organohydrogen polysiloxane that contains a hydrogen atom; a platinum-based catalyst; and an emulsifier. In the silicone emulsion composition, a specific glycol is contained.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a silicone emulsion composition for release coatings that can be applied thinly and uniformly to give release coatings with excellent coating appearance, and to a method for producing release coatings using the same. [Background technology]

[0002] It is known that silicone-based release coating compositions can impart properties such as release characteristics, releasability, and water repellency to a substrate surface by coating the surface. For example, in protective films and release films used in the manufacture of pressure-sensitive adhesives and electronic components such as ceramic capacitors, release properties are imparted to the plastic film substrate by forming a cured silicone coating on the surface of the plastic film. In recent years, release coatings have also been used for optical adhesives for touch panels and displays, and in the processing of electronic components such as ceramic capacitors.

[0003] Silicone-based release coating compositions are broadly classified into solvent-based, solventless, and emulsion types. The solvent-based release coating composition is dissolved in an organic solvent, but the use of organic solvents poses problems of safety to the human body, environmental impact, and high cost. Therefore, solvent-free release coating compositions that do not contain organic solvents have also been used, but because they have a higher viscosity than solvent-based compositions, it is difficult to achieve a thin coating thickness, which results in high costs. The emulsion type is a coating composition emulsified with an emulsifier, and allows for a thin coating thickness.

[0004] There are two types of processes for applying a release coating composition to a sheet-like substrate: "in-line film coating," in which the release coating composition is applied during the substrate manufacturing and stretching process; and "off-line film coating," in which the sheet-like substrate is manufactured and then the release coating composition is applied outside the system independently. Until now, emulsion-based release coating compositions have been primarily used for in-line film coating, while solvent-based or solventless release coating compositions have been primarily used for off-line film coating.

[0005] When using solvent-based offline film coating, there are safety and environmental issues associated with the organic solvents used. However, changing to a solventless system requires significant modifications to the equipment, which was designed for solvent-based systems, resulting in significant capital investment costs. One solution would be to switch to an emulsion type, but an oil-in-water silicone emulsion release coating composition would have poor wettability to the substrate, necessitating a thick coating thickness for uniform application. Attempting to reduce the coating thickness poses the problem that the emulsion is repelled by the surface of the substrate when applied to a sheet-like substrate, preventing uniform application.

[0006] For example, Patent Document 1 discloses an emulsion-type release coating composition, which states that it can be used for both in-line and offline film coating. In the case of in-line film coating, it is possible to obtain a uniform coating film by increasing the coating thickness, and then thin the film thickness by stretching the substrate. However, in the case of offline film coating, the substrate is not stretched after applying the release coating composition, so the coating film cannot be thinned by stretching the substrate. Therefore, reducing the amount of coating applied is considered to reduce the thickness, but this results in the problem of insufficient coating film uniformity. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Publication No. 2017-119852 Summary of the Invention [Problem to be solved by the invention]

[0008] In light of the above, there has been a demand for an emulsion composition for release coatings that can be applied in a thin coating thickness and that can be applied uniformly, particularly in off-line film coating. Furthermore, release coatings are required to have high transparency, but if the coating is not uniform after application, the release coating will tend to become cloudy or develop polka dot patterns after curing, resulting in poor coating appearance, and the release force of the release coating will also tend to be uneven. SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a silicone emulsion composition for release coatings that can be applied thinly and uniformly to give release coatings with excellent coating appearance, and a method for producing release coatings using the same. [Means for solving the problem]

[0009] The present inventors discovered that the problems of the present invention can be solved by blending a specific glycol into a silicone emulsion composition for release coatings containing (A) an alkenyl-containing diorganopolysiloxane, (B) an organohydrogenpolysiloxane containing hydrogen atoms, a platinum catalyst, and an emulsifier, and thus completed the present invention.

[0010] That is, the present invention is (A) a diorganopolysiloxane having an average composition formula represented by general formula (1) and containing two or more alkenyl groups bonded to silicon atoms in each molecule; R 1 a R 2 b SiO (4-a-b) / 2 (1) (In the formula, R 1 are the same or different monovalent hydrocarbon groups containing no aliphatic unsaturated groups, R 2 is an alkenyl group, a is 0.998 to 2.998, b is 0.002 to 2, and a+b is 1 to 3. (B) an organohydrogenpolysiloxane having an average composition formula represented by general formula (2) and containing two or more hydrogen atoms bonded to silicon atoms in each molecule; R 3 c H d SiO (4-c-d) / 2 (2) (In the formula, R 3 are the same or different monovalent hydrocarbon groups that do not contain aliphatic unsaturated groups, c is 0.998 to 2.998, d is 0.002 to 2, and c + d is 1 to 3. (C) a glycol having a surface tension of 25 to 50 N / m at 20°C; (D) a platinum group catalyst; (E) an emulsifier; (F) water, The silicone emulsion composition comprises: [Effects of the Invention]

[0011] When used for release coatings, the silicone emulsion composition of the present invention can be applied thinly and uniformly to a substrate, and is useful as a composition for obtaining release coatings that have a good coating appearance after curing. DETAILED DESCRIPTION OF THE INVENTION

[0012] The silicone emulsion composition and the method for producing a release coating using the silicone emulsion composition according to the present invention will be described in detail below.

[0013] The silicone emulsion composition according to the present invention comprises: (A) a diorganopolysiloxane having an average composition formula represented by general formula (1) and containing two or more alkenyl groups bonded to silicon atoms in each molecule; R 1 a R 2 b SiO (4-a-b) / 2 (1) (In the formula, R 1 are the same or different monovalent hydrocarbon groups containing no aliphatic unsaturated groups, R 2 is an alkenyl group, a is 0.998 to 2.998, b is 0.002 to 2, and a+b is 1 to 3. (B) an organohydrogenpolysiloxane having an average composition formula represented by general formula (2) and containing two or more hydrogen atoms bonded to silicon atoms in each molecule; R 3 c H d SiO (4-c-d) / 2 (2) (In the formula, R 3 are the same or different monovalent hydrocarbon groups that do not contain aliphatic unsaturated groups, c is 0.998 to 2.998, d is 0.002 to 2, and c + d is 1 to 3. (C) a glycol having a surface tension of 25 to 50 N / m at 20°C; (D) a platinum group catalyst; (E) an emulsifier; (F) water, Includes:

[0014] (Component (A)) Component (A) is a diorganopolysiloxane whose average compositional formula is represented by general formula (1) and which contains two or more alkenyl groups bonded to silicon atoms per molecule. Hereinafter, the diorganopolysiloxane of component (A) will also be referred to as alkenylorganopolysiloxane. R 1 a R 2 b SiO (4-a-b) / 2 (1) In formula (1), R 1 are the same or different monovalent hydrocarbon groups containing no aliphatic unsaturated groups, R 2 is an alkenyl group, a is 0.998 to 2.998, b is 0.002 to 2, and a+b is 1 to 3. In formula (1), R 1 Preferably, R has 1 to 18 carbon atoms. 1 is preferably SiC-bonded. 1 is preferably a substituted or unsubstituted hydrocarbon group that does not contain an aliphatic carbon-carbon multiple bond. In formula (1), R 2 Preferably, R has 1 to 18 carbon atoms. 2is preferably a monovalent hydrocarbon group having an aliphatic carbon-carbon multiple bond. In formula (1), a is 0.998 to 2.998, b is 0.002 to 2, and a+b is 1 to 3. In addition, the alkenylorganopolysiloxane represented by general formula (1) has an average of at least two R 2 is preferably present.

[0015] There are no particular restrictions on the viscosity of the alkenylorganopolysiloxane, and the viscosity at 25°C may be 5 to 100,000 mPa·s.

[0016] Examples of alkenyl groups in component (A) include alkenyl groups having 2 to 8 carbon atoms, such as vinyl, allyl, 1-butenyl, and 1-hexenyl. Vinyl and allyl groups are preferred, with vinyl being particularly preferred. These alkenyl groups react with component (B), described below, to form a network structure. There are an average of about two alkenyl groups per molecule of component (A), preferably 1.6 to 2.2. Such alkenyl groups may be bonded to silicon atoms at the ends of the molecular chain or to silicon atoms in the middle of the molecular chain (i.e., in the side chains).

[0017] The other organic group bonded to the silicon atom in component (A) is preferably a substituted or unsubstituted monovalent hydrocarbon group having 1 to 12 carbon atoms and containing no aliphatic unsaturated bonds. Specific examples of the other organic group include alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, t-butyl, pentyl, neopentyl, hexyl, 2-ethylhexyl, heptyl, octyl, nonyl, decyl, and dodecyl; cycloalkyl groups such as cyclopentyl, cyclohexyl, and cycloheptyl; allyl groups such as phenyl, tolyl, xylyl, biphenyl, and naphthyl; aralkyl groups such as benzyl, phenylethyl, phenylpropyl, and methylbenzyl; and substituted hydrocarbon groups in which some or all of the hydrogen atoms in these hydrocarbon groups have been substituted with halogen atoms, cyano groups, or the like, such as chloromethyl, 2-bromoethyl, 3,3,3-trifluoropropyl, 3-chloropropyl, chlorophenyl, dibromophenyl, tetrachlorophenyl, difluorophenyl, β-cyanoethyl, γ-cyanopropyl, and β-cyanopropyl. Particularly preferred organic groups are methyl and phenyl groups.

[0018] (A) The alkenylorganopolysiloxane may be linear or branched, or may be a mixture thereof. (A) alkenylorganopolysiloxane may have alkenyl groups only at both molecular terminals, only at molecular side chains, or a mixture thereof, or may have alkenyl groups at both molecular terminals and at molecular side chains.

[0019] Component (A) can further contain one having -SiOH groups at some of the molecular chain terminals. The ratio of the number of silicon atoms having OH groups to the total number of terminal silicon atoms possessed by all organopolysiloxanes in component (A) is an amount less than 5%, preferably less than 2%. If the OH group content is 5% or more, the addition polymerization is likely to converge, which may result in insufficient curing.

[0020] The alkenylorganopolysiloxanes are prepared by methods known to those skilled in the art. The viscosity of the alkenylorganopolysiloxane (A) at 25°C is preferably within the range of 5 to 2,000,000 mPa·s, more preferably 50 to 1,000,000 mPa·s, and particularly preferably 100 to 50,000 mPa·s. If the viscosity is lower than 5 mPa·s or higher than 2,000,000 mPa·s, emulsification is difficult and a stable emulsion cannot be obtained. Furthermore, the content of component (A) in the silicone emulsion composition is 0.01 to 30% by mass. If it exceeds 30% by mass, the viscosity of the aqueous emulsion may increase, making it difficult to handle. A more preferable content is 12 to 28% by mass.

[0021] The alkenyl group-containing polyorganosiloxane of component (A) is produced by methods known to those skilled in the art, and can be produced by condensation and / or ring-opening polymerization of linear and / or cyclic low molecular weight siloxanes using an acid catalyst such as sulfuric acid, hydrochloric acid, nitric acid, activated clay, or tris(2-chloroethyl)phosphite, or a base catalyst such as lithium hydroxide, sodium hydroxide, potassium hydroxide, tetramethylammonium hydroxide, tetra-n-butylammonium hydroxide, tetra-n-butylphosphonium hydroxide, sodium silanolate, or potassium silanolate.

[0022] ((B) component) Component (B) is a crosslinking component that, together with component (A), forms a cured product through an addition curing reaction between SiH groups and alkenyl groups. Component (B) is an organohydrogenpolysiloxane containing two or more silicon-bonded hydrogen atoms per molecule.

[0023] The organohydrogenpolysiloxane (B) is represented by the following average composition formula (2). R 3 c H d SiO (4-c-d) / 2 (2) In formula (2), R 3are the same or different monovalent hydrocarbon groups that do not contain aliphatic unsaturated groups, c is 0.998 to 3, d is 0.0002 to 2, and c+d is 1 to 3. 3 As for R 1 The hydrocarbon groups exemplified in are preferably alkyl groups, more preferably methyl groups. Preferably, there are two or more hydrogen atoms bonded to silicon atoms in each molecule of component (B). The viscosity of component (B) at 25°C is typically 1 to 3,000 mPa, and preferably 20 to 1,000 mPa. A viscosity within this range can prevent component (B) from volatilizing before the curing reaction with component (A) has sufficiently progressed, or prevent deterioration of curability due to low reactivity with component (A). The content of component (B) in the silicone emulsion composition of the present invention is 0.01 to 30% by mass. If it exceeds 30% by mass, the viscosity of the aqueous emulsion may increase, making it difficult to handle. A more preferred content is 12 to 28% by mass.

[0024] The amount of component (B) in the composition of the present invention is determined according to the amount of alkenyl in component (A). It is adjusted so that the ratio (NH / NA) of the number of silicon-bonded alkenyl groups in component (A) (NA) to the number of silicon-bonded hydrogen atoms in component (B) (NH) satisfies 1.0≦(NH / NA)≦6.0, preferably 1.5≦(NH / NA)≦4.0. If the NH / NA ratio is less than 1, the composition will not cure sufficiently, and unreacted alkenyl groups will remain in the coating layer, resulting in a change in release force over time and a decrease in residual adhesion due to the formation of a migratory component. Furthermore, if the NH / NA ratio is 6 or greater, the release force will likely increase over time due to the residual organohydrogenpolysiloxane in the coating layer. Component (B) is also prepared by methods known to those skilled in the art.

[0025] If the ratio of the number of silicon atoms bonded to hydrogen atoms to the total number of silicon atoms in component (B) is within the range of 1 to 30% on average, a release coating film with low peel strength under slow peeling conditions can be obtained by reducing the crosslink density and increasing the degree of freedom of the alkylsiloxane chain.

[0026] Component (B) may further contain one having -SiOH groups at some of the molecular chain terminals. The ratio of the number of silicon atoms having OH groups to the total number of terminal silicon atoms possessed by all organopolysiloxanes in component (B) is an amount less than 5%, preferably less than 2%. If the OH group content is 5% or more, the addition polymerization is likely to converge, which may result in insufficient effectiveness.

[0027] Components (A) and (B) may further contain octamethylcyclotetrasiloxane (D4), decamethylcyclopentasiloxane (D5), and dodecamethylcyclohexasiloxane (D6). The content of these compounds, relative to the total mass of components (A) and (B), is preferably 3,000 ppm by mass or less, more preferably 10,000 ppm by mass or less, and even more preferably 500 ppm by mass or less. Within the above range, the storage stability and emulsion stability are further improved.

[0028] ((C) component) Component (C) is a component that enhances the wettability of the silicone emulsion composition to the substrate when used in release coating applications, and is also expected to have the effect of suppressing the collapse of emulsion particles even in highly diluted silicone emulsion compositions, making it a component that can improve the coating appearance of the resulting release coating. In this specification, the silicone emulsion composition of the present invention used for release coating applications is also referred to as a silicone emulsion composition for release coatings. Specifically, component (C) is a glycol having a surface tension at 20°C of 25 to 50 mN / m.

[0029] If the surface tension of component (C) is within the above range, when used in release coating applications, it can reduce the surface tension of the oil-in-water silicone emulsion composition (hereinafter sometimes simply referred to as emulsion) without causing the emulsion particles to collapse. More specifically, it orients together with emulsifier (E) at the gas-liquid interface between the emulsion and air, and at the solid-liquid interface between the emulsion and the substrate on which the release coating is formed, thereby reducing the surface tension and, as a result, improving the wettability of the emulsion to the substrate. In general, in oil-in-water emulsions emulsified with surfactants, the number of surfactants present at the oil-water interface decreases in the diluted state due to reversible adsorption and desorption of the surfactant onto the emulsion particles, which tends to reduce the stability of the emulsion particles. On the other hand, in the silicone emulsion composition for release coatings of the present invention, the glycol having a surface tension within the above range also orients together with the emulsifier (E) at the liquid-liquid interface between the oil and water phases of the emulsion particles, stabilizing the emulsion particles. Therefore, even in highly diluted conditions (i.e., when the oil content that forms the emulsion particles in an oil-in-water emulsion is low), it is possible to prevent the emulsion from collapsing or the particle size from increasing due to coalescence of the emulsion particles.

[0030] Therefore, when the silicone emulsion composition for release coatings is applied to a substrate and then dried, a thin, uniform coating film is obtained. When this coating film is cured, a release coating is obtained on the substrate. Because the release coating thus obtained is thin and uniform, it has high transparency and a good coating appearance without polka-dot-like opaque areas or unevenness.

[0031] The surface tension of component (C) may be in the range of 25 to 50 mN / m, more preferably in the range of 25 to 30 mN / m, and even more preferably in the range of 26 to 28 mN / m. Component (C) may be a single component or a mixture of two or more glycols. To prevent separation or creaming in the oil-in-water silicone emulsion composition and maintain a stable emulsified state, it is preferable to use a glycol (C) that is highly water-soluble. The solubility of the glycol (C) in water is preferably 10 g / L or more, more preferably 50 g / L or more, and even more preferably 100 g / L or more.

[0032] Specific examples of component (C) include ethylene glycol mono-n-butyl ether (surface tension: 27.7 mN / m, HLB value: 7.35), ethylene glycol monoisopropyl ether (surface tension: 27.8 mN / m, HLB value: 7.825), diethylene glycol dimethyl ether (surface tension: 25.6 mN / m, HLB value: 8.05), ethylene glycol (surface tension: 48 mN / m, HLB value: 9.85), ethylene glycol monomethyl ether (surface tension: 27.7 mN / m, HLB value: 8.775), ethylene glycol monoallyl ether (surface tension: 27 mN / m, HLB value: 7.825), ethylene glycol Examples include mono-normal hexyl ether (surface tension: 26 mN / m, HLB value: 6.40), diethylene glycol monoethyl ether (surface tension: 31.3 mN / m, HLB value: 7.35), butanediol (surface tension: 32 mN / m, HLB value: 7.60), polyethylene glycol (surface tension: 27 mN / m), dipropylene glycol dimethyl ether (surface tension: 25.9 mN / m, HLB value: 5.80), dipropylene glycol methyl-n-propyl ether (surface tension: 25.2 mN / m, HLB value: 4.375), and propylene glycol monomethyl ether (surface tension: 27.7 mN / m, HLB value: 8.30).

[0033] In this specification, the "surface tension" is a value measured by the Wilhelmy method using a surface tensiometer at a liquid temperature of 25°C. An example of a surface tensiometer is the fully automatic surface tensiometer "CBVP-Z" (manufactured by Kyowa Interface Science Co., Ltd.).

[0034] There are no particular restrictions on the number average molecular weight of component (C) and it may be, for example, from 60 to 30,000, preferably from 60 to 150, and even more preferably from 100 to 150. A number average molecular weight of from 60 to 150 makes it possible to further reduce the dynamic surface tension of the silicone emulsion composition for release coatings, thereby improving the adsorption of component (C) to the interface with the substrate when the emulsion is applied to the substrate and to the oil-water phase interface of the emulsion particles.

[0035] The HLB value of component (C) is not particularly limited and may be, for example, 6.0 or greater but less than 8.0. Within this range, component (C) is more easily adsorbed by both the emulsion particles and the substrate. The HLB value of component (C) is preferably 7.0 or greater but less than 7.5, and even more preferably 7.3 or greater but less than 7.9. As component (C), a mixture of a glycol having an HLB value within the above range and a glycol having an HLB value exceeding the above range can also be used.

[0036] The HLB value in this specification refers to an HLB value calculated by the Davies method, which is a common method for calculating HLB and can be calculated using the following formula. HLB = 7 + Σ (number of hydrophilic groups) + Σ (number of lipophilic groups)

[0037] The component (C) may be a glycol represented by the following general formula (3). R 4 O(CHCHR 5 O) n H (3) (R 4 represents a hydrogen atom, an alkyl group or an alkenyl group having 1 to 6 carbon atoms and which may have a substituent, and R 5 represents hydrogen or a methyl group, and n represents a natural number from 1 to 3. R 4 If the hydrocarbon group is a long, straight-chain group, it is easy to adsorb to both the emulsion particles and the substrate, and is therefore particularly effective in improving wettability and coating appearance. 4Examples of the alkyl group include a normal propyl group, a normal butyl group, a normal pentyl group, and a normal hexyl group, with a normal butyl group being particularly preferred.

[0038] Component (C) may be a single component, or a mixture of two or more glycols. In this case, for example, the mixture may contain a first glycol having a number average molecular weight of 100 or more and a second glycol having a number average molecular weight of 80 or less. As mentioned above, the first glycol primarily reduces the surface tension of the emulsion, improving wetting and preventing emulsion particle collapse, while the second glycol has a small number-average molecular weight, resulting in a large number of moles per unit mass. This effectively raises the boiling point of water by dissolving in the water portion of the silicone emulsion composition for release coatings. This effectively slows the drying rate of the silicone emulsion composition for release coatings applied to a substrate. This allows the applied emulsion to thoroughly wet and spread over the substrate before drying, resulting in a more uniform coating and enabling the release coating to have a better, more transparent appearance after curing. More preferably, the second glycol has two or more OH groups.

[0039] The synergistic effect of the first glycol and the second glycol as described above is most pronounced when ethylene glycol mono-normal butyl ether is used as the first glycol and ethylene glycol is used as the second glycol.

[0040] When component (C) contains a first glycol and a second glycol, the blending ratio (first glycol) / (second glycol) is preferably 1.0 / 1.0 to 3.0 / 1.0, and more preferably 1.5 / 1.0 to 2.5 / 1.0. Within this range, the effects of the first glycol on wettability and coating appearance can be sufficiently maintained, while the second glycol can suppress the drying rate, thereby further improving the coating appearance.

[0041] ((D) component) Component (D) is a platinum group catalyst. This can be used as a hydrosilylation catalyst. The platinum group catalyst (D) consists of a metal or a compound containing this metal. Examples of metals constituting the platinum group catalyst (B) include platinum, rhodium, palladium, ruthenium, and iridium, with platinum being preferred. Alternatively, compounds containing these metals can be used. Among these, platinum-based catalysts are particularly suitable due to their high reactivity. The metal may be fixed on a fine particle support material (for example, activated carbon, aluminum oxide, or silicon oxide). Examples of platinum compounds include platinum halides (e.g., PtCl4, HPtCl4·6H2O, Na2PtCl4·4H2O, and reaction products of HPtCl4·6H2O with cyclohexane), platinum-olefin complexes, platinum-alcohol complexes, platinum-alcoholate complexes, platinum-ether complexes, platinum-aldehyde complexes, platinum-ketone complexes, platinum-vinylsiloxane complexes (e.g., platinum-1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex, bis-(γ-picoline)-platinum dichloride, trimethylenedipyridine-platinum dichloride, dicyclopentadiene-platinum dichloride, cyclooctadiene-platinum dichloride, cyclopentadiene-platinum dichloride), bis(alkynyl)bis(triphenylphosphine)platinum complexes, and bis(alkynyl)(cyclooctadiene)platinum complexes. The hydrosilylation catalyst can also be used in a microencapsulated form. In this case, the catalyst-containing fine particle solid insoluble in the polyorganosiloxane is, for example, a thermoplastic resin (e.g., polyester resin or silicone resin). The platinum-based catalyst can also be used in the form of an inclusion compound, for example, in cyclodextrin.

[0042] The silicone emulsion composition for release coatings contains a platinum group catalyst (D) in an amount that results in 1 to 500 ppm, preferably 5 to 200 ppm, and more preferably 20 to 100 ppm of platinum group metal relative to the weight of component (A). If the content is less than 1 ppm, curing may take a long time, which may reduce production efficiency. If the content exceeds 500 ppm, the pot life of the coating liquid may be shortened, and gelation of the coating liquid may result in reduced productivity.

[0043] ((E) component) The emulsifier (E) in the present invention can be any of various known substances, and can be appropriately selected depending on the properties of the components (A) to (D) and the required properties of the emulsion composition. The emulsifier (E) may be a cationic surfactant, a nonionic surfactant, an anionic surfactant, a protective colloid, or a mixture thereof.

[0044] In the silicone emulsion composition for release coating, the emulsifier (E) is a nonionic surfactant. Antiperspirants or protective colloids are particularly suitable. When a protective colloid is used as an emulsifier, a release coating having high emulsion stability and more stable release force can be obtained. When an ionic surfactant, such as a cationic or anionic surfactant, is used as the emulsifier, the emulsifier remaining on the film surface may adhere to the electronic components and affect their performance. Therefore, for release films used for electronic components, protective colloids with low ionicity, such as polyvinyl alcohol, or nonionic surfactants are particularly suitable.

[0045] Examples of protective colloids that can be used include polymeric compounds such as unmodified polyvinyl alcohol, acetoacetylated polyvinyl alcohol, ethylene-modified polyvinyl alcohol, polyvinylpyrrolidone, polyacrylamide, polymethacrylamide, and polycarboxylic acids, as well as alkali metal salts and / or ammonium salts thereof. Unmodified polyvinyl alcohol is particularly preferred.

[0046] As the nonionic surfactant, a nonionic surfactant having an HLB value, which indicates the balance between hydrophilicity and lipophilicity, of 8.0 to 19.0 may be used, with 10.0 to 18.0 being preferred, and 10.0 to 16.0 being more preferred. Storage stability and dilution stability tend to be improved within the above range. Surfactants with low HLB values ​​may also be used in combination as other emulsifying aids.

[0047] Examples of such nonionic surfactants include sorbitan fatty acid esters, glycerin fatty acid esters, decaglycerin fatty acid esters, polyglycerin fatty acid esters, propylene glycol pentaerythritol fatty acid esters, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene sorbit fatty acid esters, polyoxyethylene glycerin fatty acid esters, polyethylene glycol fatty acid esters, polyoxyethylene alkyl ethers, polyoxyethylene polyoxypropylene alkyl ethers, polyoxyethylene alkylphenyl ethers, polyoxyethylene castor oil, hydrogenated castor oil, polyoxyethylene alkylamine fatty acid amides, and polyalkylglycosides. These nonionic surfactants are preferred in terms of safety, stability, and cost, and can be used alone or as a mixture of two or more types. In particular, polyoxyethylene alkyl ethers are preferred from the viewpoint of emulsion stability.

[0048] The content of component (E) in the silicone emulsion composition for release coatings of the present invention is 1 to 10% by mass. If it is less than 1% by mass, emulsification is difficult, and if it exceeds 10% by mass, the viscosity of the aqueous emulsion composition increases, making it difficult to handle. A content of 3 to 6% by mass is more preferable.

[0049] (Component (F)) Component (F) is water. There are no particular limitations on the water (F), but it is preferable to use ion-exchanged water. The pH of ion-exchanged water is preferably 2 to 12, and particularly preferably 4 to 10. The use of mineral water is not recommended, but when used, it is preferable to use it in combination with a metal deactivator or the like. The amount of water added during emulsification corresponds to 20 to 80% by weight, preferably 35 to 70% by weight, of the silicone emulsion composition for release coating of the present invention. The emulsion of the present invention is stable to dilution with water, and can be further diluted after preparation of the emulsion. There is no particular limit to the amount of water (dilution water) used for dilution, but a higher solid content tends to reduce repellency when applied to a substrate, while a lower solid content tends to make it easier to obtain a good coating appearance in the release coating after curing. Because the oil-in-water silicone emulsion of the present invention is a water-solvent system, it is also preferred in that it is more environmentally friendly than systems that use solvents.

[0050] The present invention also provides a method for improving the coating appearance of a release coating formed on a substrate, comprising: (A) a diorganopolysiloxane having an average composition formula represented by general formula (1) and containing two or more alkenyl groups bonded to silicon atoms in each molecule; R 1 a R 2 b SiO (4-a-b) / 2 (1) (In the formula, R 1 are the same or different monovalent hydrocarbon groups containing no aliphatic unsaturated groups, R 2 Haa a is 0.998 to 2.998, b is 0.002 to 2, and a+b is 1 to 3. (B) an organohydrogenpolysiloxane having an average composition formula represented by general formula (2) and containing two or more hydrogen atoms bonded to silicon atoms in each molecule; R 3 c H d SiO (4-c-d) / 2 (2) (In the formula, R 3are the same or different monovalent hydrocarbon groups that do not contain aliphatic unsaturated groups, c is 0.998 to 2.998, d is 0.002 to 2, and c + d is 1 to 3. (D) a platinum group catalyst; (E) an emulsifier; (F) water, and an oil-in-water silicone emulsion composition for application to a substrate, comprising: (C) A method of blending glycol having a surface tension of 25 to 50 mN / m at 20°C.

[0051] The present invention also provides a composition comprising: (A) a diorganopolysiloxane having an average composition formula represented by general formula (1) and containing two or more alkenyl groups bonded to silicon atoms in each molecule; R 1 a R 2 b SiO (4-a-b) / 2 (1) (In the formula, R 1 are the same or different monovalent hydrocarbon groups containing no aliphatic unsaturated groups, R 2 Haa a is 0.998 to 2.998, b is 0.002 to 2, and a+b is 1 to 3. (B) an organohydrogenpolysiloxane having an average composition formula represented by general formula (2) and containing two or more hydrogen atoms bonded to silicon atoms in each molecule; R 3 c H d SiO (4-c-d) / 2 (2) (In the formula, R 3 are the same or different monovalent hydrocarbon groups that do not contain aliphatic unsaturated groups, c is 0.998 to 2.998, d is 0.002 to 2, and c + d is 1 to 3. (C) a glycol having a surface tension of 25 to 50 mN / m at 20°C; (D) a platinum group catalyst; (E) an emulsifier; (F) water, a component (A) emulsifying step of emulsifying the component (A) to obtain an emulsion containing the component (A); a component (B) emulsifying step of emulsifying the component (B) to obtain a component (B)-containing emulsion; a component (C) addition step of adding the component (C) to an emulsion containing at least one of the component (A)-containing emulsion and the component (B)-containing emulsion; The method includes:

[0052] The silicone emulsion composition for release coatings of the present invention is produced by a production method comprising a component (A) emulsifying step of emulsifying the component (A) with water (F) using the emulsifier (E) and a component (B) emulsifying step of emulsifying the component (B) with water (F) using the emulsifier (E). The component (A) emulsification step and the component (B) emulsification step can also be carried out simultaneously by emulsifying a mixture of components (A) and (B) with (F) using an emulsifier (E). The platinum-based catalyst may be mixed with the emulsion containing component (A) after the component (D) is emulsified in water (F) with an emulsifier (E) to form an emulsion containing component (D). Alternatively, the platinum-based catalyst may be mixed with component (A) in the component (A) emulsification step, and then emulsified with component (A), and then mixed with the emulsion containing component (B).

[0053] The (C) glycol may be added to either or both of the (A) component-containing emulsion and the (B) component-containing emulsion, or may be added after the (A) component-containing emulsion and the (B) component-containing emulsion are mixed.

[0054] The emulsion can be produced by mixing and emulsifying the above components using a commonly used mixer suitable for producing emulsions, such as a homogenizer, colloid mill, homomixer, or high-speed stator rotor stirrer. The emulsion can be produced by stirring all or part of component (A) or component (B), component (E), and water (F) to prepare a water-in-oil emulsion, and then adding the remaining water and stirring to form an oil-in-water emulsion. The method of first forming a water-in-oil emulsion and then converting it into an oil-in-water emulsion is preferred in terms of ease of adjusting the emulsion particle size and emulsion stability.

[0055] The present invention also provides a method for producing a release coating, comprising the steps of applying a silicone emulsion composition for release coatings to a substrate, drying the silicone emulsion composition applied to the substrate to obtain a coating, and heating the substrate with the coating attached thereto to form a release coating on the substrate.

[0056] The silicone emulsion release coating composition of the present invention can be used for in-line film coating, which is applied during the manufacture of a substrate, or for off-line film coating, which is applied after the substrate has been manufactured and stretched. After application, the coating is usually dried and then heated to accelerate curing to obtain a release coating.

[0057] The substrate is not particularly limited, and may be paper, a plastic film made of plastic, glass, metal, cloth, or the like. Examples of paper include fine paper, coated paper, art paper, glassine paper, polyethylene-laminated paper, kraft paper, Japanese paper, and synthetic paper. Examples of plastic films include polyethylene films, polyethylene terephthalate films, polybutylene terephthalate films, polyethylene naphthalate films, polypropylene films, polyester films, polyimide films, polyamide films, polyvinyl chloride films, polyvinylidene chloride films, polyvinyl alcohol films, polycarbonate films, polytetrafluoroethylene films, polystyrene films, polymethylpentene films, ionomers, polyacrylic acid esters, polymethacrylic acid esters, nylon ethylene-vinyl acetate copolymer films, ethylene-vinyl alcohol copolymer films, triacetyl cellulose films, polyether ether ketone films, polyether sulfine, polyphenylene sulfide films, polyurethanes, polyetherimides, modified polyphenylene ethers, polyether ether ketone, polyacrylonitrile, norbornene, cycloolefins, and cellophane. There are no particular limitations on the thickness or type of glass, and glass that has been chemically strengthened may also be used. Glass fiber may also be used, and the glass fiber may be used alone or in combination with other resins. Examples of metals include aluminum foil, copper foil, gold foil, silver foil, and nickel foil.

[0058] The silicone emulsion composition for release coatings of the present invention may be applied to a substrate by any known method, such as roll coating, reverse roll coating, gravure coating, reverse gravure coating, brush coating, spray coating, air knife coating, dipping, bar coating, spin coating, blade coating, gate roll coating, or meniscus coating. The silicone release coating emulsion composition may be applied to one or both sides of the substrate.

[0059] In the present invention, the thickness of the coating film after drying is not particularly limited and is, for example, 0.01 to 1 μm. Since reducing the thickness of the coating film improves transparency and reduces costs, the thickness is preferably 0.01 to 0.5 μm, and particularly preferably 0.01 to 0.3 μm.

[0060] The solids content (the ratio of the total amount of components (A) and (B) in the emulsion) of the silicone emulsion composition for release coating to be applied to a substrate is not particularly limited, and can be, for example, from 0.02% to 60%. A silicone emulsion composition for release coatings with a high solids content may be further diluted with water before application to a substrate. A higher dilution rate (i.e., a lower solids content) allows for a thinner release coating to be obtained. Generally, the higher the dilution ratio, the more likely the emulsion particles are to collapse, and the more likely the solids are to become unevenly distributed or become liberated within the emulsion. However, the silicone emulsion composition for release coatings of the present invention is less likely to experience emulsion particle collapse even under highly diluted conditions, and as a result, even when a highly diluted emulsion composition is applied, the coating appearance remains good. Furthermore, when the dilution ratio is high, the relatively high water content in the emulsion makes it more likely to bleed when applied to a substrate, which in turn tends to result in an uneven coating appearance after curing. However, with the silicone emulsion composition for release coatings of the present invention, even under conditions of high dilution (for example, a solids content of 0.5% to 4%, preferably 1% to 3%), the emulsion state remains stable and there is little cissing when applied to a substrate, making it possible to obtain a uniform coating appearance, high transparency, and a thin release coating.

[0061] The silicone emulsion composition for release coatings of the present invention is applied to a substrate, dried, and a curing reaction proceeds to form a release coating. The curing reaction may be carried out at room temperature (e.g., 25°C), but the curing reaction can also be accelerated by heating for a few seconds to a few hours. The heating temperature is not particularly limited and may be, for example, 100°C or higher and 250°C or lower. The upper heating temperature limit can be determined depending on the characteristics of the substrate and the silicone emulsion composition for release coatings, and may be, for example, 120°C or 150°C. Heating can be carried out by a conventional method of curing, such as using a heated roll, a heated drum, or a hot air drying oven. [Example]

[0062] The present invention will now be described with reference to examples, although the present invention is not limited thereto.

[0063] <Method for measuring residual adhesion rate of peeling coating> Nitto No. 31B (manufactured by Nitto Denko Corporation) was attached to a release coating prepared by the method for preparing a release coating described later, and pressed with a roller. 2After aging, the tape was peeled off from the release coating and pressed onto a stainless steel plate with a roller, and the peel strength of the tape was measured at a peel angle of 180° and a peel speed of 0.3 m / min. This value was taken as the peel strength from the stainless steel plate after it had been attached to the release coating. Nitto No. 31B (manufactured by Nitto Denko Corporation) was pressed onto a stainless steel plate with a roller, and the peel force of the tape was measured at a peel angle of 180° and a peel speed of 0.3 m / min. The value was taken as the peel force from the blank stainless steel plate. The residual adhesion rate (%) was calculated by dividing the peel force from the stainless steel plate after bonding to the release coating by the peel force from the blank stainless steel plate x 100. If the residual adhesion rate is 90% or more, it is determined that the curing is sufficient.

[0064] <Curability evaluation method> The coated surface of a release coating prepared by the method for preparing a release coating described below was evaluated by rubbing it strongly with a finger five times. If the coated surface became cloudy and white (a condition called smearing), it was judged that the curing was insufficient. If no change was observed on the coated surface, it was judged that there were no problems with curing (passed).

[0065] <Evaluation of adhesion to substrate> The coated surface of a release coating prepared by the release coating preparation method described below was evaluated by rubbing it strongly with a finger five times. If the release coating peeled off (a condition called rub-off), the adhesion was judged to be insufficient. If no change was observed on the coated surface, the adhesion was judged to be satisfactory (passed).

[0066] <Evaluation of the wettability of silicone emulsion compositions for release coatings to substrates> The silicone emulsion compositions for release coatings of the Examples and Comparative Examples described below were applied to Ester G2C (50 μm thick) manufactured by Toyobo Film Solutions Co., Ltd. After application, the coating was left at room temperature for 1 minute, and the occurrence of twisting or cissing was visually observed. The evaluation results are shown in Tables 2 to 6. The evaluation was as follows: A: No twisting or repelling is observed. B: Some twisting is observed, but no repelling occurs. C: Cracks occur in some areas D: Cracks appear on the entire surface

[0067] <Contact angle evaluation of silicone emulsion compositions for release coatings> The uniformity and thinness of the release coating silicone emulsion composition applied to a substrate can be evaluated by measuring the contact angle of the release coating silicone emulsion composition when applied to the substrate.A release coating silicone emulsion composition that can be applied thinly and uniformly to a substrate tends to exhibit a lower contact angle value.In particular, when the contact angle value is small, the coating appearance evaluation and wettability evaluation results also tend to be good.However, even if the contact angle value is large, these evaluation results may also be relatively high, so it is necessary to comprehensively evaluate the contact angle, coating appearance, and wettability. The contact angle was measured as follows. The silicone emulsion compositions for release coatings of the examples and comparative examples described below were dropped in an amount of 0.3 to 0.5 μl onto a PET film (Ester G2C, manufactured by Toyobo Film Solutions Co., Ltd.), and the contact angle was measured using a contact angle meter (Model CA-X150, manufactured by Kyowa Interface Science Co., Ltd.).

[0068] <How to evaluate coating appearance> The release coatings prepared by the method for preparing the release coating described below were visually inspected for the occurrence of phenomena resulting from surface irregularities such as twists, streaks, and spot abnormalities. The evaluation results are shown in Tables 2 to 6. The evaluation was as follows: 0: Conspicuous twisting and streaking occurs over the entire surface, and numerous spots with a diameter of 2 mm or more are observed. +: Occurrence of twists, streaks, and spots with a diameter of 2 mm or more on the entire surface. ++: Some areas have twists, streaks, and spots with a diameter of less than 1 mm. +++: Some twisting and streaking are observed, and spots of 1 mm or less in diameter are occasionally observed. ++++: No twists or streaks, slight thin spot abnormalities of 1mm or less in diameter +++++: No twists, streaks, or spots, and a smooth, clean surface

[0069] <Method for preparing silicone emulsion composition for release coating> Silicone emulsions (I) to (IV) were prepared as follows and mixed with a silane coupling agent and purified water in the blending ratios shown in Table 1 to prepare base liquids 1 and 2. Base liquid 1 contains silicone emulsions (I), (II), and (IV), while base liquid 2 contains silicone emulsions (II) and (III). Note that the numerical values ​​for blending ratios shown in tables in this specification indicate parts by mass. Next, the silicone emulsion compositions for release coatings of Examples and Comparative Examples were obtained by mixing the following base liquid 1 or base liquid 2 with glycol and purified water according to the blending ratios shown in Tables 2 to 6. Each silicone emulsion composition for release coatings was adjusted so that the total amount of components (A) and (B) was 2% by mass. The blending amounts shown in Tables 2 to 6 are based on 100 parts by mass of the entire silicone emulsion composition for release coatings. Furthermore, the "total amount of glycol" indicates the total amount of glycol added to each silicone emulsion composition for release coatings.

[0070] (Silicone emulsion (I)) First, 48.0 parts by mass of a vinyl-containing polydimethylsiloxane (A) corresponding to component (A) whose both ends are capped with dimethylvinylsilyl groups and whose viscosity is 250 mPa s, 10.0 parts by mass of polyvinyl alcohol (PVA) (E) corresponding to component (E) as a protective colloid, 42.0 parts by mass of purified water, and 0.2 parts by mass of 1-ethynyl-1-cyclohexanol were stirred at 4000 rpm using an IKA Ultra Turrax T50 Basic Shaft Generator G45M to prepare silicone emulsion (I).

[0071] (Silicone emulsion (II)) First, 35.0 parts by mass of a methylhydrogenpolysiloxane corresponding to component (B) having SiH groups on the side chains and both molecular chain terminals blocked with trimethylsiloxy groups and having a viscosity of 40 mPa s (25°C), 5.0 parts by mass of a nonionic surfactant corresponding to component (E) (Pegnol T10 / 80 manufactured by Toho Chemical Industry Co., Ltd.), and 60.0 parts by mass of purified water were stirred at 4000 rpm using an IKA Ultra Turrax T50 Basic Shaft Generator G45M, to prepare silicone emulsion (II).

[0072] (Silicone emulsion (III)) First, 25.0 parts by mass of a vinyl-containing polydimethylsiloxane having a viscosity of 1000 mPa·s and both ends of which are capped with dimethylvinylsilyl groups, corresponding to component (A), and 25.0 parts by mass of a vinyl-containing polydimethylsiloxane having a viscosity of 20000 mPa·s and both ends of which are capped with dimethylvinylsilyl groups, corresponding to component (D), 0.5 parts by mass of a platinum-vinylsiloxane complex solution having a platinum atom content of 1% by mass, corresponding to component (D), 0.11 parts by mass of 1-ethynyl-1-cyclohexanol (manufactured by Nissin Chemical Industry Co., Ltd.), 6.5 parts by mass of a nonionic surfactant (Pegnol T10 / 80, manufactured by Toho Chemical Industry Co., Ltd.), corresponding to component (E), and 43.0 parts by mass of purified water were stirred at 4000 rpm using an Ultra Turrax T50 Basic Shaft Generator G45M manufactured by IKA, to prepare silicone emulsion (III). The platinum content was 100 ppm based on the weight of the diorganopolysiloxane (A).

[0073] (Silicone emulsion (IV)) First, 45.0 parts by mass of vinyl-containing polydimethylsiloxane (A) corresponding to component (A) with a viscosity of 500 mPa·s and both ends blocked with dimethylvinylsilyl groups, 5.0 parts by mass of platinum-vinylsiloxane complex solution with a platinum atom content of 1% by mass corresponding to component (D), 4.0 parts by mass of a nonionic surfactant (Pegnol T10 / 80 manufactured by Toho Chemical Industry Co., Ltd.) corresponding to component (E), and 46.0 parts by mass of purified water were stirred at 4000 rpm using an Ultra Turrax T50 Basic Shaft Generator G45M manufactured by IKA, to prepare silicone emulsion (IV).

[0074] (Silane coupling agent) As an optional component, a silane coupling agent, ADHESION PROMOTER HF 86 (manufactured by WACKER CHEMIE AG), was added to base liquid 1 and base liquid 2. The silane coupling agent is a component that improves the adhesion between the substrate and the release coating.

[0075] [Table 1]

[0076] ((C) Glycol) The component (C) used was ethylene glycol mono-n-butyl ether (purity >99.0% (GC)), ethylene glycol (purity >99.5% (GC)), ethylene glycol monomethyl ether (purity >99.0% (GC)), ethylene glycol monoisopropyl ether (purity >99.0% (GC)), ethylene glycol monoallyl ether (purity >98.0% (GC)), or diethylene glycol dimethyl ether (purity >99.0% (GC)). All of these glycols are manufactured by Tokyo Chemical Industry Co., Ltd., and the amounts used in the examples are shown in Tables 2 to 6.

[0077] In Examples 1 to 35 and Comparative Examples 1 to 4 shown in Tables 2 to 4, a silicone emulsion composition for release coatings containing Base Liquid 1 was used. In Examples 1 to 5 shown in Table 2, 4 to 20 parts by mass of ethylene glycol mono-normal butyl ether was blended into 100 parts by mass of the silicone emulsion composition for release coatings containing base liquid 1. Compared to the examples shown in Table 4 where no glycol was blended, the wettability was improved and the coating appearance was also improved. The coating appearance evaluation results for Examples 1 to 4 were all classified as +++ on the above evaluation criteria, but comparing these, those with higher glycol concentrations tended to have better coating appearance. That is, the coating appearance improved in the order of Example 1 to Example 4.

[0078] Examples 6 to 14 shown in Table 2 contain two glycols: ethylene glycol mono-normal butyl ether and ethylene glycol. Compared to the case of using only ethylene glycol mono-normal butyl ether, an improvement in coating appearance was observed. Furthermore, when equal amounts of the two glycols were blended, those with a higher total glycol concentration tended to have better coating appearance. When a larger amount of ethylene glycol was blended out of the two glycols (Example 10), the evaluation results for coating appearance were slightly worse.

[0079] Examples 15 to 19 shown in Table 3 contain only ethylene glycol as the glycol. Both wettability and coating appearance were improved compared to Comparative Example 1, which does not contain glycol, but the evaluation results for both wettability and coating appearance were lower than those for Examples 1 to 14, which contain ethylene glycol mono-normal butyl ether.

[0080] Examples 20 to 23 shown in Table 3 were blended with ethylene glycol monomethyl ether as the glycol, and Examples 24 to 27 were blended with ethylene glycol monoisopropyl ether. Examples 28 to 31 shown in Table 4 were blended with ethylene glycol monoallyl ether, and Examples 32 to 35 were blended with diethylene glycol dimethyl ether. Examples 20 to 35 had better wettability than Examples 15 to 19, which blended only ethylene glycol. Furthermore, the coating appearance evaluation results for all but Example 34 were classified as +, but when comparing examples with the same type of glycol, a tendency was observed where the higher the glycol concentration, the better the results.

[0081] Comparative Examples 2 to 4 shown in Table 4 contain alcohol instead of glycol. Because emulsion separation occurred in Comparative Example 2, which contained methanol; Comparative Example 3, which contained ethanol; and Comparative Example 4, which contained isopropanol, these compositions were deemed unsuitable for use as silicone emulsion compositions for release coatings, and evaluation of wettability and coating appearance was not performed. It is believed that the alcohol caused the emulsion particles to disintegrate, resulting in separation into an oil phase and a water phase.

[0082] In the contact angle evaluation results when base liquid 1 was used, particularly good results (contact angle values ​​of 30 degrees or less) were obtained in Examples 1 to 14. Among these, remarkably good results (contact angle values ​​of 5 degrees or less) were obtained in Examples 9 to 14, which contained both ethylene glycol mono-normal butyl ether and ethylene glycol and had a total glycol concentration of 20 or more. In Examples 15 to 35, the contact angle evaluation results were all 40 degrees or more, but the coating appearance and wettability evaluation results were better than those of Comparative Example 1. Therefore, in a comprehensive evaluation, it can be said that the addition of glycol was effective in Examples 15 to 35 as well.

[0083] [Table 2]

[0084] [Table 3]

[0085] [Table 4]

[0086] In Examples 41 to 56 and Comparative Example 5 shown in Tables 5 and 6, a silicone emulsion composition for release coatings containing Base Liquid 2 was used. Examples 41 to 48 shown in Table 5 contain one type of glycol. Compared with Comparative Example 5 shown in Table 6, which does not contain glycol, Examples 41 to 48 all showed improved wettability and coating appearance. Among Examples 41 to 48, the case where ethylene glycol mono-normal butyl ether was added resulted in a particularly good coating appearance, while the case where ethylene glycol was added resulted in a slightly poorer appearance. Furthermore, it was confirmed that increasing the glycol concentration tended to improve the coating appearance (Examples 47 and 48).

[0087] Examples 49 to 56 shown in Table 6 are examples in which ethylene glycol and two other glycols were blended. When ethylene glycol mono-normal butyl ether and ethylene glycol were blended, particularly good wettability and coating appearance were confirmed. Furthermore, when the ratio of the blending amounts of the two glycols was changed, particularly good results were obtained when the amounts of ethylene glycol mono-normal butyl ether and ethylene glycol were the same or when the amount of ethylene glycol was low.

[0088] The contact angle evaluation results when base liquid 2 was used showed good results (contact angle values ​​of 30 degrees or less) in all examples 41 to 56. This is thought to be due to the fact that the contact angle of the base liquid when no glycol was added was lower in base liquid 2 than in base liquid 1. Among these, in Examples 49 to 52 which contained both ethylene glycol mono-normal butyl ether and ethylene glycol and had a total glycol concentration of 20 or more, significantly good results (contact angle values ​​of 5 degrees or less) were obtained.

[0089] [Table 5]

[0090] [Table 6]

[0091] When the residual adhesion rate was measured for Examples 1 to 56, the results were all 90% or higher. Furthermore, when the curability of Examples 1 to 56 was evaluated, all of them passed the test. Furthermore, when Examples 1 to 56 were evaluated for substrate adhesion, all of them passed the test.

Claims

1. (A) a diorganopolysiloxane having an average composition formula represented by general formula (1) and containing two or more silicon-bonded alkyl groups per molecule; R １ ａ R ２ ｂ SiO （４－ａ－ｂ）／２ (1) (In the formula, R １ are the same or different monovalent hydrocarbon groups containing no aliphatic unsaturated groups, R ２ is an alkenyl group, a is 0.998 to 2.998, b is 0.002 to 2, and a+b is 1 to 3. (B) an organohydrogenpolysiloxane whose average composition formula is represented by general formula (2) and which contains two or more hydrogen atoms bonded to silicon atoms in each molecule; R ３ ｃ H ｄ SiO （４－ｃ－ｄ）／２ (2) (In the formula, R ３ are the same or different monovalent hydrocarbon groups containing no aliphatic unsaturated groups, c is 0.998 to 2.998, d is 0.002 to 2, and c+d is 1 to 3. (C-1) a glycol ether having a surface tension of 25 to 50 mN / m at 20°C and represented by the following general formula (3.1); R ４ O(CH ２ CHR ５ O) ｎ H・・・(3.1) (R ４ represents an alkyl or alkenyl group having 1 to 6 carbon atoms, which may have a substituent; R ５ represents hydrogen or a methyl group, and n represents a natural number from 1 to 3. (C-2) a glycol represented by the following general formula (3.2), R6O(CH2CHR5O)nH...(3.2) (R 6 represents a hydrogen atom, R 5 represents a hydrogen atom or a methyl group, and n represents a natural number from 1 to 3.) (D) a platinum group catalyst; (E) an emulsifier; (F) water; 1. A silicone emulsion composition comprising:

2. The number average molecular weight of the component (C-1) is 100 or more, 2. The silicone emulsion composition according to claim 1, wherein the number average molecular weight of component (C-2) is 80 or less.

3. 2. The silicone emulsion composition according to claim 1, wherein the blending ratio of component (C-1) to component (C-2) is expressed by the following formula (3.3): (C-1) component / (C-2) component = 1.0 / 1.0 to 3.0 / 1.0...(3.3)

4. 2. The silicone emulsion composition according to claim 1, wherein component (C-1) is one or more selected from the group consisting of ethylene glycol mono-n-butyl ether, ethylene glycol monomethyl ether, ethylene glycol monoisopropyl ether, and ethylene glycol monoallyl ether.

5. 2. The silicone emulsion composition according to claim 1, wherein component (C-2) is one or more selected from the group consisting of ethylene glycol, butanediol, and polyethylene glycol.

6. 2. The silicone emulsion composition according to claim 1, wherein component (C-1) has a number average molecular weight of 150 or less and an HLB value of 6.0 or greater but less than 8.

0.

7. 1. A method for improving the coating appearance of a release coating formed on a substrate, comprising: (A) a diorganopolysiloxane having an average composition formula represented by general formula (1) and containing two or more alkenyl groups bonded to silicon atoms per molecule; R １ ａ R ２ ｂ SiO （４－ａ－ｂ）／２ (1) (In the formula, R １ are the same or different monovalent hydrocarbon groups containing no aliphatic unsaturated groups, R ２ is an alkenyl group, a is 0.998 to 2.998, b is 0.002 to 2, and a+b is 1 to 3. (B) an organohydrogenpolysiloxane whose average composition formula is represented by general formula (2) and which contains two or more hydrogen atoms bonded to silicon atoms in each molecule; R ３ ｃ H ｄ SiO （４－ｃ－ｄ）／２ (2) (In the formula, R ３ are the same or different monovalent hydrocarbon groups containing no aliphatic unsaturated groups, c is 0.998 to 2.998, d is 0.002 to 2, and c+d is 1 to 3. (D) a platinum group catalyst; (E) an emulsifier; (F) water, and an oil-in-water silicone emulsion composition for application to a substrate, comprising: (C-1) A method for improving coating appearance, which comprises blending a glycol ether having a surface tension of 25 to 50 mN / m at 20°C and represented by the following general formula (3.1): R ４ O(CH ２ CHR ５ O) ｎ H・・・(3.1) (R ４ represents an alkyl or alkenyl group having 1 to 6 carbon atoms, which may have a substituent; R ５ represents hydrogen or a methyl group, and n represents a natural number from 1 to 3.

8. (A) a diorganopolysiloxane having an average composition formula represented by general formula (1) and containing two or more alkenyl groups bonded to silicon atoms per molecule; R １ ａ R ２ ｂ SiO （４－ａ－ｂ）／２ (1) (In the formula, R １ are the same or different monovalent hydrocarbon groups containing no aliphatic unsaturated groups, R ２ is an alkenyl group, a is 0.998 to 2.998, b is 0.002 to 2, and a+b is 1 to 3. (B) an organohydrogenpolysiloxane whose average composition formula is represented by general formula (2) and which contains two or more hydrogen atoms bonded to silicon atoms in each molecule; R ３ ｃ H ｄ SiO （４－ｃ－ｄ）／２ (2) (In the formula, R ３ are the same or different monovalent hydrocarbon groups containing no aliphatic unsaturated groups, c is 0.998 to 2.998, d is 0.002 to 2, and c+d is 1 to 3. (C) a glycol ether having a surface tension of 25 to 50 mN / m at 20°C and represented by the following general formula (3.1); R ４ O(CH ２ CHR ５ O) ｎ H・・・(3.1) (R ４ represents an alkyl or alkenyl group having 1 to 6 carbon atoms, which may have a substituent; R ５ represents hydrogen or a methyl group, and n represents a natural number from 1 to 3. (D) a platinum group catalyst; (E) an emulsifier; (F) water, a component (A) emulsifying step of emulsifying the component (A) to obtain an emulsion containing the component (A); a component (B) emulsifying step of emulsifying the component (B) to obtain a component (B)-containing emulsion; a component (C) addition step of adding the component (C) to an emulsion containing at least one of the component (A)-containing emulsion and the component (B)-containing emulsion; 1. A method for producing a silicone emulsion composition for release coatings, comprising:

9. applying the silicone emulsion composition for release coatings of claim 1 to a substrate; a step of drying the silicone emulsion composition applied to the substrate to obtain a coating film; forming a release coating on the substrate by heating the substrate to which the coating film is attached; Including, the solids content of the silicone emulsion composition for release coating is 3% by weight or less; The method for producing a release coating, wherein the step of forming the release coating is a step of heating the substrate to which the coating film is attached without stretching it.

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