Silicone emulsion composition for mold release agent

Abstract

To provide a silicone emulsion composition for a mold-release agent for metal mold formation, excellent in metal mold adhesion while unlikely to cause a spray nozzle to clog, with a long-term storage stability, and also to provide a mold-release agent for aluminum die-cast molding containing the silicone emulsion composition and a manufacturing method of the silicone emulsion composition.SOLUTION: A silicone emulsion composition for a mold-release agent for metal mold formation includes: (A) a silicone oil; (B) a nonionic surfactant being polyoxyalkylene alkyl ether having 9C-14C alkyl group; (C) a surfactant being fatty acid ester or alkylether of a polyoxyethylene have a 16C-20C straight-chain alkyl group; and (D) water. The component (C) has a cloud point of 50°C or more with regard to 1 wt.% aqueous solution thereof.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a silicone emulsion composition for use as a mold release agent during molding, which comprises (A) silicone oil, (B) a nonionic surfactant which is a polyoxyalkylene alkyl ether, (C) a surfactant which is a fatty acid ester or alkyl ether of polyoxyethylene, and (D) water. [Background technology]

[0002] Silicones have been widely used as mold release agents because of their excellent releasability. Silicone release agents are available in various forms, such as oil-type, emulsion-type, and solvent-type. Emulsion-type silicone compositions, in particular, can be diluted with water before use, are easy to work with, economical to use, and are safe because they do not use solvents. For this reason, various silicone emulsion compositions have been proposed as mold release agents for use in molding metal, rubber, plastic, and other products.

[0003] For example, Patent Document 1 proposes a silicone emulsion composition containing silicone oil and a nonionic surfactant having a polyoxyalkylene unit. Furthermore, Patent Document 2 proposes a silicone emulsion composition suitable for use as a mold release agent, which has excellent fluidity and stability even at high concentrations, by blending a specific alkylene oxide derivative with a silicone oil containing a high concentration of a surfactant (such as a polyethylene alkyl ether).

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-129016 [Patent Document 2] Japanese Patent Application Laid-Open No. 2006-182883 Summary of the Invention [Problem to be solved by the invention]

[0005] However, emulsion separation and oil floating may occur during storage, and further improvement in stability during long-term storage is required. Furthermore, even if the stability during storage is good, there is a problem that clogging occurs in the spray nozzle when spraying into a mold if the mechanical stability is low.

[0006] To improve the storage stability and mechanical stability of emulsions, it is possible to add anionic surfactants with high emulsifying power. However, it has been found that emulsions containing anionic surfactants are prone to the Leidenfrost effect, which causes oil droplets in the emulsion to slide sideways across the mold surface when sprayed onto a mold. As a result, the silicone component, the active ingredient in the release agent, does not adhere sufficiently to the mold, preventing the release agent from fully demonstrating its performance. To improve adhesion, it is effective to make the emulsion more easily disintegrated and promote contact between the silicone component in the emulsion and the mold, but this reduces storage stability and mechanical stability. In other words, there is a trade-off between high adhesiveness and storage stability / mechanical stability.

[0007] Therefore, there has been a demand for a release agent that is sufficiently stable during long-term storage, does not easily clog nozzles when sprayed, and has high adhesion to the mold. SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a silicone emulsion composition that has excellent long-term storage stability, is less likely to clog spray nozzles, and has good mold adhesion. [Means for solving the problem]

[0008] The present inventors have discovered that the problems of the present invention can be solved by using a surfactant containing (A) silicone oil, (B) a nonionic surfactant which is a polyoxyalkylene alkyl ether having 9 to 14 carbon atoms in the alkyl group, (C) a surfactant which is a fatty acid ester or alkyl ether of polyoxyethylene having a linear alkyl group having 16 to 20 carbon atoms, and (D) water, wherein the surfactant has a cloud point of 50°C or higher as a 1% by weight aqueous solution as component (C), and have thus completed the present invention.

[0009] That is, the present invention is (A) silicone oil; (B) a nonionic surfactant which is a polyoxyalkylene alkyl ether having an alkyl group with 9 to 14 carbon atoms; (C) a surfactant which is a fatty acid ester or alkyl ether of polyoxyethylene having a linear alkyl group having 16 to 20 carbon atoms; (D) water, The component (C) has a cloud point of 50°C or higher as measured using a 1% by weight aqueous solution. The silicone emulsion composition is characterized as a mold release agent for molding. [Effects of the Invention]

[0010] The silicone emulsion composition of the present invention has excellent long-term storage stability, and when used as a mold release agent, is less likely to clog the spray nozzle and exhibits good mold adhesion, making it useful as an emulsion for use as a mold release agent. DETAILED DESCRIPTION OF THE INVENTION

[0011] The silicone emulsion composition for use as a mold release agent for mold molding, the method for producing said composition, and the method for coating the surface of a mold made of aluminum or the like with said composition according to the present invention will be described in detail below.

[0012] The silicone emulsion composition for use as a mold release agent for mold molding according to the present invention comprises: (A) silicone oil; (B) a nonionic surfactant which is a polyoxyalkylene alkyl ether having an alkyl group with 9 to 14 carbon atoms; (C) a surfactant which is a fatty acid ester or alkyl ether of polyoxyethylene having a linear alkyl group having 16 to 20 carbon atoms; (D) water.

[0013] The silicone emulsion composition of the present invention is used as a mold release agent for molding metal, rubber, plastic, and other products. It is also suitable for use with aluminum alloys, zinc alloys, magnesium alloys, tin alloys, lead alloys, copper, copper alloys, gold, silver, iron, and iron alloys. When used as a mold release agent for aluminum, aluminum alloys, or aluminum die-cast molding, it exhibits excellent adhesion to mold surfaces even at high temperatures. Furthermore, its high mechanical stability reduces clogging of nozzles spraying the silicone emulsion composition, enabling continuous, uniform spraying. In addition to applications as a release agent, the silicone emulsion composition can also be used in applications where it is spray-applied and then heat-treated (for example, release coating applications). Details of each component are given below.

[0014] (Component (A)) The silicone oil (A) used in the present invention is a polyorganosiloxane, and its modified, branched, partially crosslinked, and copolymers with other molecules can also be used. Alkyl-modified silicones and alkylaralkyl-modified silicones are particularly suitable due to their excellent paintability. When emulsifying by adding water, the blending amount of (A) silicone oil relative to the total silicone emulsion composition can be 1 to 70% by weight, more preferably 10 to 65%, and even more preferably 30 to 60%. When using the silicone emulsion composition, it can be further diluted with water depending on the conditions of use, etc.

[0015] The (A) silicone oil can have an average degree of polymerization of 5 to 1200, preferably 30 to 700, and even more preferably 300 to 500. If the average degree of polymerization is less than 5, the effect as a release agent is insufficient, and if the average degree of polymerization exceeds 1200, the viscosity becomes too high, making emulsification difficult.

[0016] A specific example of (A) silicone oil, when expressed by a chemical formula using M units, D units, T units, and Q units, is represented by the following general formula (1). (R 1 R 2 SiO 2 / 2 )D·(R 3 R 4 R 5 SiO 1 / 2 )M·(R 6 SiO 3 / 2 )T·(SiO 4 / 2 )Q ···(1) In formula (1), D, M, T, and Q are D / (M+D+T+Q)=0 to 1, M / (M+D+T+Q)=0 to 0.5, T / (M+D+T+Q)=0 to 1, Q / (M+D+T+Q)=0 to 1, and M+D+T+Q>0. More preferably, D / (M+D+T+Q)=0.5 to 1, M / (M+D+T+Q)=0 to 0.1, T / (M+D+T+Q)=0 to 0.4, and Q / (M+D+T+Q)=0 to 1. These basically have a linear siloxane skeleton, and although they may have some branching, it is preferable that the entire molecule has a linear structure.

[0017] R 1 ~R 6 are each independently selected from the following, which may be the same or different: In making this selection, the same units, e.g. (R 1 R 2 SiO 2 / 2 )D units, R 1 Select a methyl group as R 2 In other words, three types of groups, methyl group, phenyl group, and hydrogen, can be selected at the same time. Also, the structure connecting each unit may have a different form from each unit.

[0018] R 1 ~R 6 Examples of the alkyl group include linear or branched alkyl or alkenyl groups having 1 to 20 carbon atoms and halogen-substituted alkyl or alkenyl groups, cycloalkyl or cycloalkenyl groups having 5 to 25 carbon atoms and halogen-substituted cycloalkyl or cycloalkenyl groups having 5 to 25 carbon atoms, aralkyl or aryl groups having 6 to 25 carbon atoms and halogen-substituted aralkyl or aryl groups, hydrogen, a hydroxyl group, an alkoxy group, a halogen group, an acyloxy group, a ketoximate group, an amino group, an amido group, an aminoxy group, a mercapto group, an alkenyloxy group, an acid anhydride group, a carbonyl group, a sugar, a cyano group, an oxazoline group, an isocyanate group, and / or hydrocarbon-substituted alkyl or alkenyl groups.

[0019] Preferred examples include linear or branched alkyl groups such as methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, tertiary butyl, pentyl, isopentyl, neopentyl, hexyl, isohexyl, heptyl, isoheptyl, octyl, isooctyl, nonyl, and decyl groups, and halogen-substituted alkyl groups thereof; alkenyl groups such as vinyl, allyl, and homoallyl groups; cycloalkyl groups such as cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, dicyclopentyl, and decahydronaphthyl groups, and halogen-substituted cycloalkyl groups; cycloalkenyl groups such as cyclopentenyl (1-, 2-, and 3-) and cyclohexenyl (1-, 2-, and 3-) groups; aralkyl groups and aryl groups such as phenyl, naphthyl, tetrahydronaphthyl, tolyl, and ethylphenyl groups, and halogen-substituted aryl groups thereof;

[0020] Hydrogen, hydroxyl group, methoxy group, ethoxy group, propoxy group, isopropoxy group, butoxy group, isobutoxy group, tertiary butoxy group, hexyloxy group, isohexyloxy group, 2-hexyloxy group, octyloxy group, isooctyloxy group, 2-octyloxy group, fluoro group, chloro group, bromo group, iodo group, acetoxy group, dimethylketoxime group, methylethylketoxime group, amino group, hydroxyamino group, dimethylamino group, diethylamino group, formamide group, acetamide group, aminooxy group, mercapto group, methylmercapto group, ethylmercapto group, glycidyl group,

[0021] Examples of the glycosyl group include an ethylene glycoxy group, a diethylene glycoxy group, a polyethylene glycoxy group, a propylene glycoxy group, a dipropylene glycoxy group, a polypropylene glycoxy group, a methoxyethylene glycoxy group, an ethoxyethylene glycoxy group, a methoxydiethylene glycoxy group, an ethoxydiethylene glycoxy group, a methoxypropylene glycoxy group, a methoxydipropylene glycoxy group, and an ethoxydipropylene glycoxy group.

[0022] The silicones used in the present invention can be produced by methods known in the industry as disclosed in SILICONES & INDUSTRY. Specific examples of preferred silicones include dimethyl silicone, phenylmethyl silicone, methylhydrogen siloxane, alkylaralkyl-modified silicone, fluorine-modified silicone, amino-modified silicone, various terminally reactive silicones, silicone wax, silicone resin, silicone resin oil, silicone elastomer, stearoxymethyl polysiloxane, aminomethyl aminopropyl siloxane-dimethyl siloxane copolymer, etc. When the silicone emulsion composition of the present invention is used as a mold release agent, R bonded to silicon atoms in one molecule 1 ~R 6 If at least 40 mol % of the groups are methyl groups, this is more preferable in terms of mold releasability. The preferred viscosity of these silicones is 5 to 100,000 mPa·s, and more preferably 100 to 10,000 mPa·s at 25° C. These silicones can be used alone or in combination.

[0023] (Component (B)) The nonionic surfactant (B) used in the present invention is a polyoxyalkylene alkyl ether, a nonionic surfactant having an alkyl group with 9 to 14 carbon atoms, containing 1 to 100 -CHCHO- units, and having a structure containing 1 to 100 -CHRCHO- units (R is an alkyl group), with the number of -CHCHO- units being equal to or greater than the number of -CHRCHO- units. The number of each unit is important in terms of balancing the hydrophilic groups; -CHRCHO- units are more hydrophobic than -CHCHO- units, and an increase in the number of -CHCHO- units will prevent them from fulfilling their role as hydrophilic groups. Therefore, the number of -CHCHO- units must be equal to or greater than the number of -CHRCHO- units. Furthermore, while the number of each unit may be large, it is desirable for it to be 100 or less from an economical standpoint.

[0024] Any surfactant that satisfies these requirements may be used, and the bonding state of the organic group is not particularly limited. Preferred surfactants include those having the general formula shown below. R a -Y-(CHR X CH2O) n -(CH2CH2O)mH

[0025] In the formula, R a represents a branched or linear alkyl group having 9 to 14 carbon atoms, and Y represents -O- or -COO-. m and n are each 1 to 100, and m, m', and m'' are greater than n, n', and n''. R X represents an alkyl group, such as a methyl group or an ethyl group, and CHR X The entire CH2 also includes a cycloalkylene group.

[0026] In these general formulas and the chemical formulas shown in the specification of the present invention, the ratio of the components of the copolymer and the random or block bonding of the oxyethylene chains and oxyalkylene chains are shown. a -O-(CH2CH2O) m -(CHR X CH2O) n In -H, R a It does not necessarily mean that an oxyethylene group is directly bonded to -O-, nor does it mean that the terminal is OH based on an oxyalkylene group.

[0027] Furthermore -(CHR X CH2O)n-, -(CH2CHR X O) n -Includes. More specific examples of these general formulas are as follows: R a -O-(CHR X CH2O) n -(CH2CH2O)mH, R a COO-(CHR X CH2O) n -(CH2CH2O) m -H, R a N-[(CHR X CH2O) n’ -(CH2CH2O) m’ -H][(CHR X CH2O) n’’ -(CH2CH2O) m’’ -H], R a CON-[(CHR X CH2O) n '-(CH2CH2O) m’ -H][(CHR X CH2O) n’’ -(CH2CH2O) m’’ -H], and among the general formulas exemplified above, particularly preferred are R a -O-(CHR X CH2O) n -(CH2CH2O) m -H.

[0028] Specific examples of preferred surfactants include those in which an oxyethylene chain and an oxyalkylene chain are randomly or block polymerized to a higher alcohol. General formula;R a -O-(CH2CH2O) m -(CHRXCH2O) n Examples of -H include: C 10 H 21 -O-(CH(CH3)CH2O)1-(CH2CH2O)8-H, C 10 H 21 -O-(CH(CH3)CH2O)1-(CH2CH2O)9-H, C 10 H 21 -O-(CH(CH3)CH2O)2-(CH2CH2O)8-H, C 10 H 21 -O-(CH(CH3)CH2O)3-(CH2CH2O)7-H, C 10 H 21 -O-(CH(CH3)CH2O)4-(CH2CH2O)6-H, C 10 H 21 -O-(CH(CH3)CH2O)4-(CH2CH2O) 10 -H, C 10 H 21 -O-(CH(CH3)CH 2O ) 12 -(CH2CH2O) 16 -H, C 12 H 25 -O-(CH(CH3)CH2O)1-(CH2CH2O)8-H, C 12 H 25 -O-(CH(CH3)CH2O)1-(CH2CH2O)9-H, C 12 H 25 -O-(CH(CH3)CH2O)2-(CH2CH2O)8-H, C 12 H 25-O-(CH(CH3)CH2O)3-(CH2CH2O)7-H, C 12 H 25 -O-(CH(CH3)CH2O)4-(CH2CH2O)6-H, C 12 H 25 -O-(CH(CH3)CH2O)4-(CH2CH2O) 10 -H, C 12 H 25 -O-(CH(CH3)CH 2O ) 12 -(CH2CH2O) 16 -H, C 12 H 25 -O-(CH(CH3)CH2O)6-(CH2CH2O)8-H, C 13 H 27 -O-(CH(CH3)CH2O)6-(CH2CH2O)8-H, C 13 H 27 -O-(CH(CH3)CH 2O )2-(CH2CH2O) 10 -H, Examples include:

[0029] The above formulas include isomers and may also be mixtures of these. a -O-(CH2CH2O) m -(CHR X CH2O) n -H R a The moiety may be a mixture of compounds having average carbon numbers represented by the formula shown above.

[0030] General formula;R a COO-CH2CH2O)m-(CHR X CH2O) n Specific examples of -H include C 10 H 23 -COO-(CH2CH2O)8-(CH(CH3)CH2O)1-H, C 10 H 23-COO-(CH2CH2O)9-(CH(CH3)CH2O)1-H, C 10 H 23 -COO-(CH2CH2O)8-(CH(CH3)CH2O)2-H, C 10 H 23 -COO-(CH2CH2O)7-(CH(CH3)CH2O)3-H, C 10 H 23 -COO-(CH2CH2O)6-(CH(CH3)CH2O)4-H, C 10 H 23 -COO-(CH2CH2O) 16 -(CH(CH3)CH2O) 12 -H, etc. Examples include:

[0031] The amount of nonionic surfactant (B) used in the present invention is preferably 0.1 to 50 parts by mass, more preferably 1 to 30 parts by mass, and even more preferably 3 to 15 parts by mass, per 100 parts by mass of component (A). If the amount is below this range, emulsification becomes difficult, and if the amount is above this range, the performance of the silicone oil may not be fully exhibited, and releasability may decrease.

[0032] (Component (C)) The surfactant (C) which is a fatty acid ester or ether used in the present invention is a polyoxyethylene fatty acid ester or alkyl ether, has a linear alkyl group having from 16 to 20 carbon atoms, and has a cloud point of 50°C or higher, as measured using a 1% by weight aqueous solution of component (C). Upon decomposition, the surfactant gives an alcohol having a linear alkyl group with a high melting point. When component (C) with this structure and cloud point is used, in an oil-in-water silicone emulsion in which oil droplets containing (A) silicone oil and (B) nonionic surfactant are dispersed in water, component (C) adheres to the surface of the oil droplets in the form of micelles, forming capsules. This phenomenon increases the mechanical strength and stability of the oil droplets containing components (A) and (B). As a result, not only is a highly stable silicone emulsion composition obtained that does not experience separation or oil floating even after long-term storage, but also a composition with high mechanical strength that does not collapse the oil droplets even when localized pressure or shear is applied when sprayed from a spray nozzle.

[0033] Surfactants with branched alkyl groups or alkyl groups with carbon atoms outside the above range will form a liquid crystal state (also called a lamellar structure) with a high number of associations when water is added. Further dilution will gradually loosen the liquid crystal state and result in a micellar state with a low number of associations. Therefore, at high concentrations, the micellar state cannot be achieved. On the other hand, component (C) used in the present invention is a surfactant that decomposes to give an alcohol having a high melting point and a linear alkyl group, and therefore forms a micellar state when water is added without passing through a liquid crystal state. That is, the ester surfactant of the present invention can form micelles with high concentration. Therefore, it is possible for the component (C) to tightly and densely adsorb and coat the surface of oil droplets containing components (A) and (B) in a micellar state, thereby forming aggregates exhibiting a capsule-like structure. If component (C) is a polyoxyethylene fatty acid ester, aggregates with particularly high mechanical stability can be obtained.

[0034] If the cloud point of component (C) is less than 50°C, precipitation will occur easily, and the ability to form a capsule state and improve mechanical stability will be less likely to be exhibited. The cloud point of component (C) may be 50°C or higher, but if the solution temperature is above the boiling point during cloud point measurement, the cloud point measurement is impossible. Therefore, the upper limit of the cloud point is the boiling point of the solution, which is, for example, 100°C depending on the composition of the solution.

[0035] If the alkyl group in component (C) has 15 or fewer carbon atoms, encapsulation of oil droplets will be insufficient, and if it has 21 or more carbon atoms, emulsification will be difficult. Compared with fatty acid esters having branched or cyclic alkyl groups, polyoxyethylene fatty acid esters having linear alkyl groups adhere more favorably to the surface of oil droplets and form a more robust capsule state. As long as the alkyl group is linear, it may be a saturated alkyl group or an unsaturated alkyl group having one or more unsaturated groups.

[0036] (C) Specific examples of surfactants that are fatty acid esters or alkyl ethers of polyoxyethylene are represented by chemical formulas such as the following general formulas (2) and (3). R b -(C=O)O(CH2CH2O) p -H (2) R b -(O)(CH2CH2O) p -H (3) In the formulas (2) and (3), p is 1 to 100, and more preferably 5 to 50. b is a straight-chain alkyl group having 16 to 20 carbon atoms.

[0037] Specific examples of component (C) include R b stearic acid esters, which are saturated alkyl groups with 17 carbon atoms; oleic acid esters, linoleic acid esters, linolenic acid esters, which are unsaturated alkyl groups with 17 carbon atoms; b is an arachidic acid ester where R is a saturated alkyl group having 19 carbon atoms. b Examples include arachidonic acid esters and eicosapentaenoic acid esters, which are unsaturated alkyl groups with 19 carbon atoms.

[0038] Specific examples of when component (C) is a stearate ester include polyethylene glycol monostearate (2EO) (for example, trade name: MYS-2, manufactured by Nikkol Co., Ltd., trade name: EMALEX DEG-MS, manufactured by Nippon Emulsion Co., Ltd.), Polyethylene glycol monostearate (5EO) (for example, trade name: EMALEX 805, manufactured by Nippon Emulsion Co., Ltd.), Examples of the polyethylene glycol monostearate include polyethylene glycol (10EO) monostearate (for example, trade name: MYS-10, manufactured by Nikkor Corporation, and trade name: EMALEX 810, manufactured by Nippon Emulsion Corporation), polyethylene glycol monostearate (20EO) (for example, trade name: EMALEX 820, manufactured by Nippon Emulsion Corporation), polyethylene glycol monostearate (30EO) (for example, trade name: EMALEX 830, manufactured by Nippon Emulsion Corporation), and polyethylene glycol monostearate (40EO) (for example, trade name: MYS-40, manufactured by Nikkor Corporation, and trade name: EMALEX 840, manufactured by Nippon Emulsion Corporation).

[0039] Specific examples of when component (C) is an oleate ester include polyethylene glycol monooleate (2EO) (for example, trade name: MYO-2, manufactured by Nikkol Co., Ltd.)), polyethylene glycol monooleate (6EO) (for example, trade name: EMALEX OE-6, manufactured by Nippon Emulsion Co., Ltd.)), polyethylene glycol monooleate (10EO) (for example, trade name: EMALEX OE-10, manufactured by Nippon Emulsion Co., Ltd.)), and polyethylene glycol monooleate (14EO) (for example, trade name: Pegnol 14-O, manufactured by Toho Chemical Industry Co., Ltd.)).

[0040] The amount of component (C) added in the present invention is preferably 0.1 to 30 parts by mass, more preferably 1.0 to 20 parts by mass, and even more preferably 2.0 to 10 parts by mass, per 100 parts by mass of component (A).

[0041] (Component (D)) The water (D) used in the present invention is not particularly limited, but it is preferable to use ion-exchanged water, and its pH is preferably from 2 to 12, particularly preferably from 4 to 10, and most preferably from 5 to 9. It is not recommended to use mineral water, but when used, it is preferable to use it in combination with a metal deactivator or the like.

[0042] The amount of water to be added is not particularly limited, but in the case of an emulsion composition, it is preferably used in an amount of 1 to 98.8% by weight, more preferably 10 to 95% by weight, and even more preferably 50 to 90% by weight.

[0043] The average particle size of the silicone emulsion composition of the present invention is preferably 100 to 500 nm, and more preferably 150 to 300 nm. Particles less than 100 nm are difficult to produce and tend to thicken. Particles greater than 500 nm tend to be less stable.

[0044] The present invention also provides (A) an oil-in-water silicone emulsion composition for use as a mold release agent, in which oil droplets containing silicone oil are dispersed in water, comprising: (B) a nonionic surfactant which is a polyoxyalkylene alkyl ether having an alkyl group with 9 to 14 carbon atoms; (C) a surfactant which is a fatty acid ester or alkyl ether of polyoxyethylene having a linear alkyl group having 16 to 20 carbon atoms; (D) water, The component (C) has a cloud point of 50°C or higher in a 1% by weight aqueous solution, The silicone emulsion composition contains aggregates of component (C) in a micellar state that are oriented on the surfaces of the oil droplets containing component (A) and component (B).

[0045] The silicone emulsion composition of the present invention has a morphology in which oil droplets containing (A) silicone oil are dispersed in (D) water by the aid of (B) nonionic surfactant, with component (C) surfactant adhering to their surfaces. Component (A) is the main component inside the oil droplets (near the center), with component (B) also present. Component (B) is oriented near the surface of the oil droplets, which is the interface between the water phase and the oil phase, and component (C) adsorbs thereto, forming a coating layer on the oil droplets. Component (C) is thought to adsorb in a micellar state, and may cover the entire surface of the oil droplets, or may only cover a portion of it. When the average particle size of the emulsion is 100 to 300 nm, if the weight ratio of component (C) to component (A) is in the range of 100:0.14 to 100:100, preferably 100:0.1 to 100:10, the oil droplets will be suitably encapsulated by the coating layer, and a silicone emulsion composition with excellent mechanical stability and storage stability will be obtained. If the amount of component (C) is less than the above range, encapsulation will be insufficient, resulting in reduced mechanical stability, whereas if the amount is greater than the above range, the viscosity will increase, making handling difficult. The blending ratio of component (C) relative to component (B) is not particularly limited, but the mechanical stability of the emulsion composition is higher when the weight ratio of component (B) to component (C) is in the range of 1:0.02 to 1:1, and is even higher when it is in the range of 1:0.1 to 1:0.5.

[0046] If component (C) is not included, the surfaces of the oil droplets cannot be covered with the micelles of component (C), and therefore the mechanical strength of the oil droplets is not improved. As a result, the pressure when the release agent is sprayed from the spray nozzle and the shear force applied when passing through the nozzle pores cause part of the emulsion to break down, resulting in separation into an oil phase and an aqueous phase inside the nozzle. The separated oil aggregates and solidifies inside the spray nozzle, causing the pores to become clogged. With the silicone emulsion composition of the present invention, even under pressure or shear conditions, the oil droplets are coated with micelles, creating an encapsulated state, so the emulsion is less likely to collapse. This allows the composition to be sprayed onto the mold surface in a uniform emulsion state, and nozzle clogging is also reduced.

[0047] The release agent for molding is sprayed from a spray nozzle into a high-temperature gas phase (the gas phase temperature is, for example, 30°C to 300°C) and then reaches the surface of the mold, which is at an even higher temperature (for example, 200°C to 400°C). The material of the mold is not particularly limited as long as it is a material generally used for aluminum die-cast molding, and is, for example, iron. The silicone emulsion composition of the present invention is heated in the gas phase after being sprayed from the nozzle, and component (C), whose cloud point of a 1 wt % aqueous solution is 50°C or higher, dissolves. At this time, the coating layer formed together with component (B) is destroyed, exposing the internal silicone oil (A). This silicone oil reaches the mold surface in a state separated from the water contained in the emulsion composition. Because the mold surface is at a high temperature, a silicone oil film is formed (it is baked onto the mold surface). Because only the silicone oil forms a film on the mold surface, high adhesion is achieved, and the silicone oil exhibits good performance as a mold release agent.

[0048] On the other hand, even for emulsions that do not contain component (C) and are not encapsulated, it is possible to improve the mechanical stability of the emulsion by, for example, adding an anionic surfactant. However, in this case, the highly stable emulsion that does not collapse inside the nozzle is sprayed onto the mold surface while maintaining its emulsion state. The water contained in the emulsion then rapidly evaporates on the mold surface, creating a layer of vapor between the oil droplets and the mold. As a result, the oil droplets containing the silicone oil, the active ingredient in the release agent, slide sideways, preventing the silicone oil inside the droplets from adhering to the mold surface and forming a film (the Leidenfrost effect). This reduces adhesion, resulting in insufficient performance as a release agent.

[0049] The present invention also provides a method for producing a silicone emulsion composition, comprising: an emulsification step of emulsifying (A) silicone oil and (D) water with (B) a surfactant which is a polyoxyalkylene alkyl ether having from 9 to 14 carbon atoms in the alkyl group; and a step of adding and stirring (C) a surfactant which is a fatty acid ester or alkyl ether of polyoxyethylene having a linear alkyl group having from 16 to 20 carbon atoms, thereby coating the surfaces of the oil droplets in the emulsion obtained in the emulsification step with component (C) in a micellar state.

[0050] A preferred example of a method for producing the silicone emulsion composition of the present invention is shown below. (1) (A) Silicone oil and (B) Polyoxyalkylene alkyl ether surfactant are mixed, and water for phase inversion, for example, about the same amount as component (B), is added and forcibly stirred with a homomixer. A small amount of water is added and further stirred with the homomixer to cause phase inversion, and the mixture is then diluted with water to the desired concentration. Thereafter, (C) a surfactant which is a fatty acid ester or alkyl ether of polyoxyethylene is added and further stirred. Optionally, other additives such as a preservative may also be added.

[0051] (2) (B) Polyoxyalkylene alkyl ether surfactant is mixed with water for phase inversion, for example, water in an amount equal to that of component (B), and (A) silicone oil is added stepwise while forcibly stirring with a homomixer. A small amount of water is then added and stirred with a homomixer to cause phase inversion, and the mixture is then diluted with water to the desired concentration. Then, component (C) is added and further stirred. Optionally, other additives such as preservatives may also be added.

[0052] (3) (B) Mix the surfactant, which is polyoxyalkylene alkyl ether, with the entire amount of water, and add (A) silicone oil while stirring with a mixer. Thereafter, the surfactant (component (C)) is added and further stirred. Optionally, other additives such as preservatives may also be added.

[0053] In the present invention, the water that needs to be added before the phase inversion in these methods is called initial water, and the water added thereafter to adjust the emulsion concentration is called dilution water. In the above invention, the water (D) to be added includes both initial water and dilution water.

[0054] Other additives may be added to the composition of the present invention as long as they do not contradict the spirit of the present invention, such as antibacterial agents, antifungal agents, preservatives, pH adjusters, colorants, other surfactants, antioxidants, deodorizers, crosslinking agents, various catalysts, emulsion stabilizers, various organic solvents, and chelating agents.

[0055] The silicone emulsion composition according to the present invention exhibits improved mechanical stability and improved adhesion to molds, making it suitable for use as a mold release agent for coating the surface of aluminum die casting. The method for coating a mold surface of the present invention is characterized in that a metal molding release agent containing the silicone emulsion composition of the present invention is sprayed from a spray nozzle onto the mold surface at a temperature of 200°C or higher and 400°C or lower.

[0056] The present invention also provides a method for producing a coating, which comprises spraying a release agent for aluminum die casting, which contains the silicone emulsion composition of the present invention, from a spray nozzle onto the surface of aluminum, an aluminum alloy, or an aluminum die-cast member at a temperature of 200°C or higher and 400°C or lower.

[0057] To mold a cast product of aluminum or the like, a mold release agent may be applied to a mold at room temperature (e.g., 25°C) and then a heating step may be carried out, or a preheating step may be carried out prior to casting, in which the mold is heated to a temperature of about 50°C to 250°C. In general, when casting continuously, the mold is used for the next casting before it has cooled sufficiently. Since the casting temperature is, for example, in the range of 650°C to 800°C, the mold surface temperature before the next casting is started is, for example, 50°C to 800°C, and often in the range of 200°C to 400°C, depending on the interval time, mold shape, etc. The release agent for aluminum die casting is sprayed onto the die during the preheating process, or in the case of continuous casting, between the time when the die is removed after the previous casting and the time when the next casting begins. The gas phase temperature from the spray injection point to the die is usually around 30°C to 300°C.

[0058] The release agent for aluminum die casting according to the present invention can be stored stably for a long period of time and has excellent mechanical stability, so that it can be sprayed uniformly without causing clogging in the spray nozzle. After being sprayed from the spray nozzle in an emulsion state, the release agent is heated by the temperature of the gas phase, causing the emulsion to collapse, and the silicone oil (A), which is the oil phase and active ingredient contained in the release agent, arrives at the mold surface in a state separated from the aqueous phase. Component (A) is heated on the mold surface and forms a coating. Component (A) adheres uniformly to the mold surface in a state separated from the aqueous phase, resulting in the effect of good adhesion and a coating with a uniform thickness. [Example]

[0059] The present invention will be described in detail based on examples, but the present invention is not limited to the following examples. In the examples, parts indicate parts by mass and % indicates % by weight. The viscosity was measured at a shear rate of 1.0 s at 25°C. -1 The results of the examples and comparative examples are shown in Table 1.

[0060] (Cloud point measurement method) A 1% by weight aqueous solution of the component to be measured was prepared as a cloud point test solution. The cloud point test solution was then heated to make it cloudy, and gradually cooled to a temperature at which the cloudiness disappeared, which was taken as the cloud point. The maximum heating temperature was 90°C, and if no turbidity was observed when the temperature reached 90°C, the cloud point was determined to be 90°C or higher. Cloud Point Test: When the cloudiness did not disappear even when the liquid was cooled to 0°C, the cloud point was determined to be 0°C or lower.

[0061] (Storage stability evaluation method) The silicone emulsion composition was placed in a glass screw bottle (50 ml), sealed, and left to stand for 4 weeks in a thermostatic chamber at 40° C. Changes in the emulsion composition were observed visually, and the storage stability of the emulsion was evaluated using the following three-point scale. (Evaluation criteria) A: No change in appearance and viscosity change within ±30% of the initial value B: There is reversible heterogeneity C: Oil floating or irreversible heterogeneity Reversible heterogeneity refers to a state in which changes such as separation or creaming are observed when the mixture is left standing, but the mixture returns to the initial state upon stirring. Irreversible heterogeneity refers to a state in which separation or creaming continues even after stirring, and the mixture does not return to the initial state. It is preferable that the above evaluation criteria be met.

[0062] (Mechanical stability evaluation method) The silicone emulsion composition was diluted with water to a 1.0% organopolysiloxane concentration, and 400 g of this diluted solution was placed in a 1,000 ml beaker and stirred at 8,000 rpm using a homomixer for 10 minutes. The mixture was then left to stand for 3 hours, and the presence or absence of oily matter on the beaker wall, floating oily matter on the liquid surface, and creamy matter was observed and evaluated according to the following criteria: (Evaluation criteria) S: No oily or creamy matter is observed on the liquid surface. A: There is no oil floating, but interference fringes are visible B: A very small amount of oily material and a very small amount of creamy material are observed on the surface of the liquid. C: Oily matter is observed floating on part of the liquid surface, and creamy matter is observed on the entire liquid surface. D: Oily matter and creamy matter are observed floating on the entire surface of the liquid. It is preferable that the above evaluation criteria are met to S or A.

[0063] (Adhesion evaluation method) The silicone emulsion composition was diluted with water to an organopolysiloxane concentration of 0.15%. The diluted silicone emulsion composition was sprayed onto an iron plate heated to 300°C from a height of 10 cm at a pressure of 0.1 MPaG using a spray nozzle. The spray nozzle was equipped with a 1.0 mm diameter orifice. During spraying, the temperature of the gas phase at a height of 5 cm from the heated iron plate was 50°C. The spray nozzle used was a W-100-102P spray nozzle manufactured by Anest Iwata (discharge rate adjustment knob opening: 1.5 turns). After spraying the silicone emulsion composition, the iron plate was cooled to 25°C, and a circular discolored area was observed on the iron plate. The area of ​​this discolored area was measured and evaluated according to the following criteria: (Evaluation criteria) Adhesion++++++: area 9.5cm 2 End Adhesion +++++: Area 7.0cm 2 More than 9.5cm 2 less than Adhesion++++: Area 4.5cm 2 More than 7.0cm 2 less than Adhesion +++: Area 3.0cm 2 More than 4.5cm 2 less than Adhesion++: Area 1.5cm 2 More than 3.0cm 2 less than Adhesion+: Area 1.5cm 2 less than It is preferable that the adhesion of the above evaluation standard be +++++ or higher.

[0064] Example 1 Component (A) has a viscosity of 1.2 x 10 5 50 parts by weight of organopolysiloxane 1 (WACKER® TN SILICONE RELEASE AGENT, manufactured by Wacker Chemie AG; designated A-1 in the table) modified with both long-chain alkyl groups and aralkyl groups, 5 parts by weight of component (B), a nonionic surfactant containing a 12-carbon alkyl group, eight -CH2CHO- units, and two -CHCH3CHO- units (designated B-1 in the table), and water were added and continuously stirred with an Ultra-Turrax®. Next, 1.4 parts by weight of polyethylene glycol monooleate (containing 14 -CH2CHO- units and having a cloud point of 90°C or higher; designated C-1 in the table) was added as component (C), and the mixture was stirred to obtain Silicone Emulsion Composition 1. The content of each component is also listed in Tables 1 and 2.

[0065] Example 2 Silicone emulsion composition 2 was obtained in the same manner as in Example 1, except that 5 parts by mass of a nonionic surfactant (referred to as B-2 in the table) containing an alkyl group with a prime number of 12, 19 -CH2CH2O- units, and 4 -CHCH3CH2O- units was used as component (B).

[0066] Example 3 Component (A) has a viscosity of 1.0 x 10 5 Silicone emulsion composition 3 was obtained in the same manner as in Example 2, except that 50 parts by mass of organopolysiloxane 2 (WACKER (registered trademark) 23166VP SILICONE RELEASE AGENT manufactured by Wacker Chemie AG; designated as A-2 in the table) modified with a long-chain alkyl group and having a viscosity of 100 MPa·s was used.

[0067] Example 4 Component (A) has a viscosity of 1.3 x 10 5 Silicone emulsion composition 4 was obtained in the same manner as in Example 2, except that 50 parts by mass of organopolysiloxane 2 (WACKER (registered trademark) GM196 SILICONE RELEASE AGENT manufactured by Wacker Chemie AG; designated as A-3 in the table) modified with both a long-chain alkyl group and an aralkyl group, having a viscosity of 100 MPa·s, was used.

[0068] Example 5 Silicone emulsion composition 5 was obtained in the same manner as in Example 1, except that 1.4 parts by mass of polyethylene glycol monostearate (containing 40 -CHCHO- units and having a cloud point of 90°C or higher; shown as C-2 in the table) was used as component (C).

[0069] Example 6 Silicone emulsion composition 6 was obtained in the same manner as in Example 1, except that 1.4 parts by mass of polyoxyethylene cetyl ether (containing a linear alkyl group having 16 carbon atoms and 16 -CHCHO- units, and having a cloud point of 60°C; designated C-3 in the table) was used as component (C).

[0070] (Comparative Example 1) Comparative silicone emulsion composition 1 was obtained in the same manner as in Example 1, except that the surfactant corresponding to component (C) was not used.

[0071] (Comparative Example 2) Comparative silicone emulsion composition 2 was obtained in the same manner as in Example 2, except that the surfactant corresponding to component (C) was not used.

[0072] (Comparative Example 3) Comparative silicone emulsion composition 3 was obtained in the same manner as in Example 3, except that the surfactant corresponding to component (C) was not used.

[0073] Comparative Example 4 Comparative silicone emulsion composition 4 was obtained in the same manner as in Example 4, except that the surfactant corresponding to component (C) was not used.

[0074] (Comparative Example 5) It does not contain a surfactant equivalent to component (C), and is an anionic surfactant, polyoxyethylene lauryl ether sodium sulfate C 12 H 25 Comparative silicone emulsion composition 5 was obtained in the same manner as in Example 5, except that 4.25 parts by mass of —(CH2CH2O)3SO3Na was used and the amount of component (B) blended was 0.75 parts by mass.

[0075] (Comparative Example 6) Component (C) is a polyoxyalkylene alkyl ether surfactant. 18 H 37Comparative silicone emulsion composition 6 was obtained in the same manner as in Example 2, except that (-CH2CH2O-)5H (cloud point below 0°C; designated C-4 in the table) was used.

[0076] (Comparative Example 7) Comparative silicone emulsion composition 7 was obtained in the same manner as in Example 2, except that octyldodecyl ether having a branched alkyl group (cloud point of 0°C or lower; listed as C-5 in the table) was used as component (C).

[0077] The silicone emulsion compositions 1 to 6 and comparative silicone emulsion compositions 1 to 7 obtained above were evaluated for storage stability, mechanical stability, and adhesion, and the results are shown in Tables 1 and 2. The storage stability and mechanical stability were high and the adhesion was also good in Examples 1 to 6. In Comparative Examples 1 to 5, a component corresponding to component (C) was not blended, and as a result, the mechanical stability was reduced. Furthermore, in Comparative Example 3, unevenness occurred in the adhered coating, and in Comparative Example 5, the adhesion was poor. In Comparative Example 6, the cloud point 0 It is believed that the mechanical stability was reduced due to the insufficient encapsulation of the ether surfactant, and that the storage stability was also reduced at the same time. A surfactant having a branched alkyl group was used in Comparative Example 7. Even if the carbon number is within the range of 16 to 20, when the alkyl group has a branched structure, it is thought that the formation of micelles that cover the surfaces of the oil droplets is insufficient, resulting in a decrease in mechanical stability and a decrease in the storage stability curve.

[0078] [Table 1]

[0079] [Table 2]

Claims

1. (A) an alkylaralkyl-modified silicone; (B) a nonionic surfactant which is a polyoxyalkylene alkyl ether having an alkyl group with 9 to 14 carbon atoms; (C) a surfactant which is a fatty acid ester or alkyl ether of polyoxyethylene having a linear alkyl group having from 16 to 20 carbon atoms; (D) water, The component (B) is —CH ２ CH ２ 1 to 100 O-units, and -CHRCH ２ O-unit (-CH ２ It has a structure containing 1 to 100 —CHRO- units (hereinafter the same; R is an alkyl group), ２ CH ２ O-unit number is -CHRCH ２ O-unit number or more, The cloud point of a 1 wt % aqueous solution of the component (C) is 50°C or higher. Silicone emulsion composition for use as a mold release agent for molding.

2. (A) An oil-in-water silicone emulsion composition for use as a mold release agent, in which oil droplets containing alkylaralkyl-modified silicone are dispersed in water, (B) a nonionic surfactant which is a polyoxyalkylene alkyl ether having an alkyl group with 9 to 14 carbon atoms; (C) a surfactant which is a fatty acid ester or alkyl ether of polyoxyethylene having a linear alkyl group having from 16 to 20 carbon atoms; (D) water, The component (C) has a cloud point of 50°C or higher in a 1% by weight aqueous solution, the component (C) is in a micellar state and contains aggregates that are oriented on the surface of the oil droplets and contain the component (A) and the component (B); The component (B) is —CH ２ CH ２ 1 to 100 O-units, and -CHRCH ２ O-unit (-CH ２ It has a structure containing 1 to 100 —CHRO- units (hereinafter the same; R is an alkyl group), ２ CH ２ O-unit number is -CHRCH ２ The silicone emulsion composition has a number of O-units or more.

3. 1 to 70 parts by mass of the component (A), The component (B) is in an amount of 0.1 to 50 parts by mass, based on 100 parts by mass of the component (A). The component (C) is in an amount of 0.1 to 30 parts by mass, based on 100 parts by mass of the component (A), The component (D) The silicone emulsion composition according to claim 1 or 2.

4. A mold release agent for aluminum die casting, comprising the silicone emulsion composition according to any one of claims 1 to 3.

5. an emulsification step of emulsifying (A) silicone oil and (D) water with (B) a surfactant that is a polyoxyalkylene alkyl ether having an alkyl group with 9 to 14 carbon atoms; (C) adding a surfactant which is a fatty acid ester or alkyl ether of polyoxyethylene having a linear alkyl group having from 16 to 20 carbon atoms and stirring the mixture to coat the surfaces of the oil droplets in the emulsion obtained in the emulsification step with component (C) in a micellar state, The component (B) is —CH ２ CH ２ 1 to 100 O-units, and -CHRCH ２ O-unit (-CH ２ It has a structure containing 1 to 100 —CHRO- units (hereinafter the same; R is an alkyl group), ２ CH ２ O-unit number is -CHRCH ２ O-unit number or more, The component (C) has a cloud point of 50°C or higher in a 1 wt% aqueous solution. A method for producing a silicone emulsion composition.

6. A method for improving the mechanical stability and adhesion to a mold of a silicone emulsion composition for use as a mold release agent, comprising the steps of: A mixture containing (A) silicone oil, (B) a surfactant that is a polyoxyalkylene alkyl ether having an alkyl group with 9 to 14 carbon atoms, and (D) water is emulsified, and then (C) adding a surfactant which is a fatty acid ester or alkyl ether of polyoxyethylene having a linear alkyl group having from 16 to 20 carbon atoms; The component (B) is —CH ２ CH ２ 1 to 100 O-units, and -CHRCH ２ O-unit (-CH ２ It has a structure containing 1 to 100 —CHRO- units (hereinafter the same; R is an alkyl group), ２ CH ２ O-unit number is -CHRCH ２ O-unit number or more, The method according to claim 1, wherein the component (C) has a cloud point of 50°C or higher in a 1 wt% aqueous solution.

7. A method for coating a mold surface, comprising spraying a metal molding release agent containing the silicone emulsion composition according to any one of claims 1 to 3 from a spray nozzle onto the mold surface at a temperature of 200°C to 400°C.

8. 5. A method for producing a coating on a mold surface, comprising spraying the release agent for aluminum die casting according to claim 4 from a spray nozzle onto the mold surface at a temperature of 200° C. to 400° C.

9. (A) silicone oil; (B) a nonionic surfactant which is a polyoxyalkylene alkyl ether having an alkyl group having from 9 to 14 carbon atoms; (C) a surfactant which is a fatty acid ester or alkyl ether of polyoxyethylene having a linear alkyl group having from 16 to 20 carbon atoms; (D) water, and a method for improving the mechanical stability of a silicone emulsion composition for use as a mold release agent, comprising: The component (B) is —CH ２ CH ２ 1 to 100 O-units, and -CHRCH ２ O-unit (-CH ２ It has a structure containing 1 to 100 —CHRO- units (hereinafter the same; R is an alkyl group), ２ CH ２ O-unit number is -CHRCH ２ O-unit number or more, The component (C) has a cloud point of 50°C or higher as measured using a 1% by weight aqueous solution, The component (B) disperses oil droplets containing the component (A) in water, By forming aggregates in which the surfaces of the oil droplets are coated with component (C) in a micellar state, A method for improving the mechanical stability of the silicone emulsion composition.

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