JP2021063171A - Liquid crystal emulsification method of oil-in-water type emulsion - Google Patents

Abstract

To provide a method for producing an oil-in-water type emulsion by a liquid crystal emulsification method.SOLUTION: A liquid crystal emulsification method is provided, by which a water-in-oil type pre-emulsion of a silicone composition and a nonionic surfactant is continuously converted into an oil-in-water type emulsion via a liquid crystal phase. The method includes: a step of producing the water-in-oil type pre-emulsion by selecting a quantitative ratio of the nonionic surfactant to an oil amount; a step of allowing the water-in-oil type pre-emulsion to flow into a sealed space and imparting shear energy to form a liquid crystal phase as a preparation state for forming an oil-in-water type emulsion; and a step of adding water to the liquid crystal phase outflowing from the sealed space to form the oil-in-water type emulsion. The method includes a step of setting the temperature of the water-in-oil type pre-emulsion depending on the quantitative ratio of the surfactant to the oil amount in the step of producing the water-in-oil type pre-emulsion, so as to avoid completion of an endothermic reaction by the liquid-crystallization of the water-in-oil type pre-emulsion at the time when the liquid crystal phase outflows from the sealed space.SELECTED DRAWING: Figure 1

Description

The present invention relates to a liquid crystal emulsification method for an oil-in-water emulsion. More specifically, when an oil-in-water emulsion is produced by a liquid crystal emulsification method, oil droplets of the oil-in-water emulsion are formed while continuously forming a liquid crystal phase. The present invention relates to a method for producing an oil-in-water emulsion capable of controlling the particle size and particle size distribution of particles and suppressing the expansion of the particle size.

A liquid crystal emulsification method is known for producing an oil-in-water emulsion by converting a water-in-oil preemulsion into an oil-in-water emulsion via a liquid crystal phase (Non-Patent Document 1).
When the oil-in-water emulsion is directly produced, it is difficult to secure the stability of the emulsion due to the variation in the particle size of the oil droplets. The liquid crystal emulsification method using an oil-type emulsion is often used.
When a water-in-oil pre-emulsion is used as the liquid crystal phase, for example, a method is known in which shear energy due to shearing is applied to the pre-emulsion until the pre-emulsion flows into a predetermined gap between the stator and the rotating rotor and flows out. (Patent Document 1).
In this case, depending on the viscosity of the pre-emulsion, the shear energy imparted to the pre-emulsion by the shear rate corresponding to the rotation speed of the rotor and the shear time corresponding to the time from inflow to the predetermined gap of the pre-emulsion to the outflow. However, in the case of the stator / rotor type, the rotation speed of the rotor is generally high, while the shear time is short, which causes the following technical problems.

First, the liquid crystal phase occurs when the preemulsion is given extra energy due to the difficulty in adjusting the shear energy applied to the preemulsion and the liquid crystal phase is formed from the preemulsion. Is excessively heated, which causes the diameter of the oil droplet particles of the oil-in-water emulsion produced via the liquid crystal phase to increase. More specifically, by flowing the pre-emulsion into a predetermined gap between the rotating rotor and the stator, shear energy is given to the pre-emulsion and used for activation energy of the pre-emulsion, thereby being used in oil. When the liquid crystal phase, which is a transition state between the water-type pre-emulsion and the oil-in-water emulsion, is formed, the viscosity of the pre-emulsion rapidly increases until the liquid crystal phase is formed.
In the liquid crystal emulsification method, forming a so-called lamellar uniform laminated structure (hereinafter referred to as "liquid crystal lamella") as the liquid crystal phase leads to the production of oil droplet particles of an emulsion having a uniform particle size. It is known. The smaller the distance between the layers, that is, the higher the cohesiveness of the liquid crystal lamella, the smaller the particle size. However, it is necessary to rearrange by subdivision while maintaining the structure of the minute part as the liquid crystal phase as the lamella. ..
However, when the temperature of the liquid crystal phase is excessively high, the subdivided structures are united, resulting in an increase in diameter, which has been a problem.

Combined with such a rapid increase and change in viscosity, the pre-emulsion is given the energy necessary for forming the liquid crystal phase structure, and by not giving extra energy, such a temperature rise can be prevented. Therefore, it is difficult to prevent the diameter of the oil droplet particles of the oil-in-water emulsion from expanding.
In this respect, in the case of batch-type liquid crystal phase formation, it is possible to form a liquid crystal phase by putting a pre-emulsion into an open container, storing it in the container, and repeatedly shearing it by circulation. Although it takes time to form the liquid crystal phase by increasing the shearing time while reducing the speed, it is relatively easy to adjust the energy required for forming the liquid crystal phase, and a cooling jacket is provided on the outside of the container. Therefore, it is relatively easy to prevent the temperature of the liquid crystal phase from rising.

On the other hand, in the case of continuous liquid crystal phase formation, the shear rate is increased and the shearing time is shortened, so that the liquid crystal phase formation does not require time, but the following technical problems are caused. ..
First, it is difficult to adjust the energy required for forming the liquid crystal phase, and it is also difficult to prevent the temperature rise of the liquid crystal phase itself by cooling.
More specifically, for example, the liquid crystal phase is formed by flowing the preemulsion into the closed container, shearing it in a one-through method, and then letting it flow out of the closed container. Although the oil-in-water emulsion can be efficiently produced, the shearing time is short and the shearing force must be increased, so that it is difficult to adjust the shearing energy required for forming the liquid crystal phase.
Therefore, shear energy equal to or greater than the shear energy required for forming the liquid crystal phase is applied in the closed container, and as a result, the temperature of the liquid crystal phase tends to rise due to the fact that the container is closed.
Excessive temperature rise of the liquid crystal phase causes the diameter of the oil droplet particles of the oil-in-water emulsion produced through the liquid crystal phase to increase.
Such an increase in the diameter of the oil droplet particles makes it difficult to satisfy the product specifications when the oil droplet particles are used as an oil-in-water emulsion, for example, as a coating agent, an additive to cosmetics, or the like. Become.
In the liquid crystal emulsification method, it is desired not only to prevent such an increase in the diameter of the oil droplet particles, but also to positively adjust the particle size of the oil droplet particles.

Second, the particle size distribution of the oil droplet particles of the oil-in-water emulsion formed based on the liquid crystal phase tends to widen.
More specifically, the shear energy of the rotating rotor is determined by the viscosity and shear rate of the pre-emulsion, but the shear energy is given to the pre-emulsion because the pre-emulsion flows into a predetermined gap and flows out from the predetermined gap. Since this time interval depends on the shear rate, fluctuations in the shear rate (rotor rotation speed) hinder the uniformity of the formed liquid crystal phase, and are based on the liquid crystal phase. The particle size distribution of the oil droplet particles of the oil-in-water emulsion formed tends to widen.

In this regard, if the fluctuation of the shear rate is suppressed regardless of the rapid increase and change of the viscosity of the pre-emulsion, that is, if the rotation speed of the rotor is not left to decrease but is kept constant, such a particle size is used. While it is possible to suppress the spread of the distribution, the shear energy applied to the pre-emulsion increases as the viscosity of the pre-emulsion increases and changes, and as described above, the particle size of the oil droplet particles increases. Causes the change.
As described above, in particular, in the one-through continuous type in which the pre-emulsion is allowed to flow in and out of a predetermined gap and shear energy is applied between them, the problem of increasing the average particle size of the oil droplet particles and the oil The problem of spreading the particle size distribution of droplet particles is an incompatible issue.
Furthermore, there was no way to positively control the particle size itself.
In this respect, in the batch type, the particle size of the oil droplet particles can be adjusted to some extent, but it is difficult to apply shear energy to the pre-emulsion without any spatial bias in the container. It is difficult to suppress the spread of the particle size distribution of the droplet particles.

J. Soc. Cosmet. Jpn., Vol.44 ,, No.2 (2010), p.103

Japanese Unexamined Patent Publication No. 2012-77282

In view of the above technical problems, an object of the present invention is that when an oil-in-water emulsion is produced by a liquid crystal emulsification method, the particle size of oil droplets of the oil-in-water emulsion is formed while forming a liquid crystal phase by a continuous method. It is an object of the present invention to provide a method for producing an oil-in-water emulsion capable of suppressing the expansion of the diameter of the emulsion.
In view of the above technical problems, an object of the present invention is that when an oil-in-water emulsion is produced by a liquid crystal emulsification method, the particle size of oil droplets of the oil-in-water emulsion is formed while forming a liquid crystal phase by a continuous method. It is an object of the present invention to provide a method for producing an oil-in-water emulsion, which can suppress the expansion of the particle size, adjust the particle size, and suppress the spread of the particle size distribution of oil droplet particles.

A method for continuously producing an oil-in-water emulsion to achieve the above problems is to continuously produce an oil-in-water emulsion via a liquid crystal phase using a water-in-oil preemulsion of a silicone composition and a nonionic surfactant. It is a liquid crystal emulsification method to be manufactured
At the stage of producing a water-in-oil preemulsion by selecting the ratio of the amount of nonionic surfactant to the amount of oil,
By applying shear energy to the water-in-oil pre-emulsion in the closed space until the water-in-oil pre-emulsion at a predetermined flow rate flows into the closed space and flows out of the closed space, the oil-in-water emulsion can be produced. The stage of forming the liquid crystal phase so that it is ready for formation,
It has a stage of forming an oil-in-water emulsion by adding water to the liquid crystal phase flowing out of the closed space.
The ratio of the amount of surfactant to the amount of oil in the production stage of the water-in-oil preemulsion so that the heat absorption reaction due to the liquefaction of the water-in-oil preemulsion does not end when the liquid crystal phase flows out of the closed space. It is configured to have a step of setting the temperature of the water-in-oil preemulsion according to the above.
In the present invention, the "water-in-oil pre-emulsion" defines a water-in-oil emulsion which is a precursor of the "oil-in-water emulsion" intended by the present invention. However, it does not necessarily have to be in the form of a water-based emulsion in oil, and it may be in a state where oil and water are mixed and integrated.

According to the present inventor, in a water-in-oil preemulsion, when a liquid crystal phase is formed, the frictional heat generated by shearing (slip) fluctuates according to the level of viscosity due to the cohesiveness of the lamella, while in oil. The liquid crystal phase formation from the start of applying shear energy to the water-type preemulsion to the preparation state for the formation of the oil-in-water emulsion, that is, the rearrangement by the formation and subdivision of the liquid crystal lamella, is mainly due to the heat absorption reaction. Focusing on a certain point, the excessive temperature rise of the water-in-oil preemulsion at the end of applying shear energy to the water-in-oil preemulsion is suppressed, and the particle size of the oil droplets of the oil-in-water emulsion resulting from this is suppressed. It was found that the expansion of the diameter of the liquid crystal was suppressed.

The liquid crystal lamella is a form of a liquid crystal phase formed mainly by agglomeration of a surfactant. The liquid crystal lamella is a state in which three kinds of components, a surfactant, an oil, and water, are formed in layers.
Since liquid crystal lamellas require a certain amount of activation energy under shearing, they are endothermic. The higher the degree of cohesion of lamella, the greater the activation energy.
The liquid crystal lamella formed in the water-in-oil emulsion usually has a higher-order structure. When further shearing is continued, this higher-order structure is rearranged by subdivision. In this way, the formation of the liquid crystal phase is completed. Endothermic occurs at this stage as well. The temperature range in which subdivision occurs is generally in the range of −5 ° C. to 40 ° C.

The lower the temperature of the water-in-oil preemulsion is set, the higher the cohesiveness of the liquid crystal lamella and the higher the viscosity, so that the frictional heat when applying shear energy to the water-in-oil preemulsion is applied. However, as the viscosity decreases due to the increase in temperature due to shearing, the generation of frictional heat becomes more gradual.
On the other hand, as the temperature of the water-in-oil preemulsion is set to a lower temperature, the endothermic reaction required for the formation of the liquid crystal phase up to the state of preparation for the formation of the oil-in-water emulsion continues over a long span.
Therefore, the lower the temperature of the water-in-oil preemulsion is set, the more the generation of frictional heat is suppressed at the completion of the formation of the liquid crystal phase, while the endothermic reaction is required. The degree of temperature rise of the liquid crystal phase in the state becomes gradual.
In particular, the silicone composition is suitable for the present invention because it has high hydrophobicity but is excellent in stability at the level of −10 ° C.

Further, as a method for continuously producing an oil-in-water emulsion for achieving the above problems, an oil-in-water emulsion is used via a liquid crystal phase using a water-in-oil preemulsion of a silicone composition and a nonionic surfactant. Is a liquid crystal emulsification method that continuously produces
At the stage of producing a water-in-oil preemulsion by selecting the ratio of the amount of nonionic surfactant to the amount of oil,
A liquid crystal composed of a liquid crystal lamella by applying shear energy to the water-in-oil preemulsion in the closed space until a predetermined flow rate of the water-in-oil preemulsion flows into the closed space and flows out from the closed space. As well as forming a phase
The stage of adjusting the cohesiveness of the liquid crystal lamella,
The stage of subdividing the formed liquid crystal phase and
It has a stage of forming an oil-in-water emulsion by adding water to the subdivided liquid crystal phase flowing out of the closed space.
The water-in-oil preemulsion so that when the liquid crystal phase flows out of the closed space, the formed liquid crystal phase is settled in the subdivision stage and has a cooling temperature that determines the cohesiveness of the liquid crystal lamella. In the production stage of the above, the water-in-oil preemulsion is cooled to a predetermined temperature according to the ratio of the amount of the surfactant to the amount of oil.

After the formation of the liquid crystal phase is completed, necessary water is added and usually reverse emulsification is performed to form an oil-in-water emulsion, but the size of the oil droplets at that time is basically the time when the liquid crystal lamella is formed. Layer spacing is reflected. The size of the oil droplet is not limited to the size of one layer of the liquid crystal lamella, but in many cases, the unit subdivided into a mass of several layers seems to determine the size of the oil droplet. If the spacing between the layers does not change or the subdivided units do not coalesce during the process of forming the liquid crystal lamella and / or the subsequent subdivision, the oil droplets in the final oil-in-water emulsion The size is determined by the spacing between the layers of the liquid crystal lamella. In addition, since liquid crystal lamellas are usually considered to have a uniform phase sensation at the time of formation, if the subdivided units do not coalesce, the distribution of the final oil droplet particle size is small. It is considered to be.

As described above, the formation of the liquid crystal phase, that is, the rearrangement due to the formation and subdivision of the liquid crystal lamella, facilitates the enlargement of the particles of the oil-in-water emulsion finally obtained through the subsequent steps, and / Or, it is an important factor that affects the particle size. The microscopic structure of the liquid crystal lamella affects the size of the final emulsion particles.
When the liquid crystal phase is formed, the viscosity usually increases due to the lamellar structure and the liquid crystal phase is gel-like. However, the liquid crystal phase itself is a transient form of existence because it no longer exists in the final oil-in-water emulsion and is therefore no longer gel-like.

Further, in the method for continuously producing an oil-in-water emulsion for achieving the above problems, the shear energy application step is a rotor that can rotate about a central axis, a rotor, and an outer cylinder with a predetermined gap. The stator is provided with a plurality of slits at predetermined angular intervals in the circumferential direction, and the water-in-oil preemulsion is allowed to flow into the predetermined gap through the slits. It is configured to have a stage of applying shear energy before it flows out.

According to the method for continuously producing an oil-in-water emulsion having the above configuration, the water-in-oil preemulsion is allowed to flow into a predetermined gap, and shear energy is given by a one-through passage method until the preemulsion flows out from the gap. , It is possible to uniformly apply shear energy to the water-in-oil pre-emulsion without variation, and thus it is formed based on the liquid crystal phase (both liquid crystal lamella and subdivided structure) to be formed and the liquid crystal phase. It is possible to improve the stability of the oil-in-water pre-emulsion to be produced.

Further, it is preferable to have a step of maintaining a constant rotation speed of the rotor until the water-in-oil preemulsion flows into the closed space and flows out.
Further, the rotation speed of the rotor may be set according to the selected temperature at the time when the liquid crystal phase formation is completed.
In addition, it further has a step of setting the inflow amount of the pre-emulsion into the enclosed space.
It is preferable to select the temperature of the water-in-oil preemulsion at the time when the liquid crystal phase formation is completed so that the stability of the water-in-oil preemulsion can be ensured according to the set inflow amount.
Furthermore, the temperature of the pre-emulsion at a water content of 5% by mass or less is preferably −40 ° C. to −5 ° C.

As described above, the lower the temperature of the pre-emulsion, the higher the cohesiveness of the liquid crystal lamella, and the finer and more uniform the lamellar structure is obtained.
Therefore, as the temperature of the pre-emulsion is lowered, the liquid crystal lamellar has a fine and uniform lamellar structure, and after being subdivided, the particle size of the oil droplets of the emulsion based on the lamellar structure becomes smaller.
Further, as described above, the lower the temperature at the time of completion of the subdivision, the more the expansion of the diameter of the emulsion particles is suppressed. If the diameter expansion is suppressed, a uniform particle size distribution will be maintained. Above -5 ° C, the emulsion particle size does not become sufficiently small. For example, it is 0.3 μm or more. Further, if the temperature is lower than -40 ° C, the water contained therein freezes and the viscosity of the pre-emulsion increases too much, which imposes a burden on the device and may prevent stable shearing. Is. More preferably, it is in the range of −30 ° C. to −20 ° C.
The temperature setting is made according to the desired emulsion particle size.
A particle size of about 0.3 μm is obtained by cooling at −5 ° C., and about 0.2 μm is obtained by cooling at −25 ° C. When the temperature is lower than -25 ° C, the stability of shear energy gradually decreases, and when cooled at -40 ° C, the particle size becomes about 0.3 μm.

Hereinafter, a suitable embodiment of an oil-in-water emulsion using a silicone composition as an oil using a nonionic surfactant will be described in detail with reference to the drawings, taking as an example the use of the release material used for the release film. To do.

In recent years, various electronic devices have become lighter, thinner, shorter, smaller, and have a multi-layer structure, and there are many cases where a release film is required when manufacturing the device. This is the surface of the release agent layer of the release film on the opposite side of the contact surface with the film substrate (hereinafter, in the manufacturing process of light, thin, short and small electronic devices for optical adhesives such as touch panels and displays and having a multi-layer structure. , This may be referred to as a peeling surface), and then a film made of another material is layered and then the film is peeled off in a later step, or another material is applied to the peeling surface (hereinafter, such a material is used. This is because steps are often used to dry it (sometimes referred to as paint) and then peel it off in a later step. The step of applying an adhesive or paint to the peeled surface, drying it, and peeling the dried product in a subsequent process is particularly frequently used in the manufacture of light, thin, short and small electronic devices having a multi-layer structure. There is. With the recent thinning of paints due to the lightening, thinning, shortening, and multi-layered structure of various electronic devices, the polar paints are thinned on the release film (in the order of several nanometers to micrometer in thickness).
It must be possible to carry out even when coating, drying and peeling.
For that purpose, the surface of the release film is required to have a high degree of smoothness, and it is required that there are as few protrusions as possible. Moreover, in order to achieve the surface condition of the release film as described above, it is required to reduce the emulsion particle size.

As the release agent used for such a release film, it is preferable to use a release agent containing silicone from the viewpoint of imparting excellent release characteristics, and moreover, it is safer than the solvent type and the solvent-free type. It is said that it is more preferable to use an emulsion type which has many advantages in terms of surface and application.

As shown in FIG. 1, the oil-in-water emulsion production system 10 is roughly composed of a water-in-oil pre-emulsion generation unit 12, a liquid crystal phase forming unit 14, and an oil-in-water emulsion production unit 16 and is in oil. The water-type pre-emulsion generation unit 12, the liquid crystal phase-forming unit 14, and the submersible oil-type emulsion generation unit 16 are connected to each other in this order through the pipe 18, and are connected by a liquid feed pump 20 arranged in the middle of the pipe 18. The water-in-oil emulsion produced in the water-in-oil pre-emulsion generation unit 12 is fed to the liquid crystal phase forming unit 14, where the transition state between the water-in-oil pre-emulsion and the oil-in-water emulsion is formed. A liquid crystal phase is formed, and the formed liquid crystal phase is liquid-fed to an oil-in-water emulsion generating unit 16, where an oil-in-water emulsion is produced so that an oil-in-water emulsion, which is the final object, is produced. ing.

The water-in-oil pre-emulsion generation unit 12 is roughly composed of an emulsification / dispersion unit 22 and a cooling unit 24, and the emulsification / dispersion unit 22 applies a shearing force to the droplets by using a mechanical stirring force to disperse the droplets. A conventional emulsifier may be used, and a high-speed stirrer typified by a homomixer, an ultrasonic homogenizer, a high-pressure homogenizer, or the like can be adopted.
In the emulsification / dispersion unit 22, the ratio of the amount of water, the amount of the silicone composition which is the oil content described later, and the amount of the nonionic surfactant described later is selected and emulsified and dispersed.

The composition of the oil-in-water silicone emulsion composition is typically:
(A) The average composition formula is represented by the general formula (1), and 20 to 60% by mass of diorganopolysiloxane containing two or more alkenyl groups bonded to silicon atoms in one molecule.
(Chemical 1)
R ¹ _a R ² bSiO _{(4-ab) / 2} (1)
(In the formula, R ¹ is the same or different monovalent hydrocarbon group containing no aliphatic unsaturated group, R ² is an alkenyl group, a is 0.998 to 2.998, b is 0.002 to 2, a + b. Is 1-3.),
(B) The average composition formula is represented by the general formula (2), and an organohydrogenpolysiloxane containing two or more hydrogen atoms bonded to a silicon atom: 5 to 30 parts by mass,
(Chemical 2)
_{^{R 6 d H e SiO (4}} -d-e) / 2 (2)
(In the formula, R ⁶ is the same or different monovalent hydrocarbon group containing no aliphatic unsaturated group, d is 0.999 to 2.999, e is 0.001 to 2, and d + e is 1 to 3. is there.)
(C) Nonionic surfactant: 1 to 10 parts by mass,
(D) Platinum-based catalyst: 1 to 500 ppm with respect to the component (A),
(E) Water: 30 to 80 parts by mass.
The composition of the oil-in-water silicone emulsion composition applicable in the present invention is not limited to the above composition. For example, instead of the above components (A) and (B), any reactive or non-reactive silicone component can be used.

(Ingredient (A))
The component (A) is a diorganopolysiloxane having an average composition formula represented by the general formula (1) and containing two or more alkenyl groups bonded to a silicon atom in one molecule. The diorganopolysiloxane of the component (A) is also hereinafter referred to as an alkenyl organopolysiloxane.
(Chemical 1)
R ¹ _a R ² _b SiO _{(4-ab) / 2} (1)
In formula (1), R ¹ is the same or different monovalent hydrocarbon group containing no aliphatic unsaturated group, R ² is an alkenyl group, a is 0.998 to 2.998, and b is 0.002 to 2. And a + b is 1 to 3.
In formula (1), R ¹ preferably has 1 to 18 carbon atoms. Further, ^{it is preferable that R 1} is SiC-bonded. Further, R ¹ is preferably a substituted or unsubstituted hydrocarbon group having no aliphatic carbon-carbon multiple bond.
In formula (1), R ² preferably has 1 to 18 carbon atoms. Further, R ² is preferably a monovalent hydrocarbon group having an aliphatic carbon-carbon multiple bond.
In the formula (1), a is 0.998 to 2.998, b is 0.002 to 2, and a + b is 1 to 3.
Further, alkenyl organopolysiloxane represented by the general formula (1) are preferably present at least two R ² on average per molecule.

The alkenyl organopolysiloxane preferably has a viscosity at 25 ° C. of 5 to 100,000 mPa · s.

As the alkenyl group in the component (A), for example, an alkenyl group having 2 to 8 carbon atoms such as a vinyl group, an allyl group, a 1-butenyl group and a 1-hexenyl group can be exemplified, and a vinyl group is preferable. , Allyl group, particularly preferably vinyl group. These alkenyl groups react with the component (E) described later to form a network structure. An average of about 2 alkenyl groups, preferably 1.6 or more and 2.2 or less, are present in the molecule of the component (A). Such an alkenyl group may be bonded to a silicon atom at the end of the molecular chain, or may be bonded to a silicon atom in the middle of the molecular chain. From the viewpoint of the curing reaction rate, an alkenyl group-containing polyorganosiloxane in which an alkenyl group is bonded only to a silicon atom at the terminal of the molecular chain is preferable.

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

The component (A) may be linear or branched, or may be a mixture thereof, but when a branched alkenyl group-containing polyorganosiloxane is contained, the crosslink density is high, so that the component (A) is slow. Since the peeling force of the siloxane becomes high and it is difficult to reach the desired peeling force, the linear shape is more preferable. This alkenyl group-containing polyorganosiloxane is produced by a method known to those skilled in the art.
The viscosity of the alkenyl organopolysiloxane (A) at 25 ° C. is preferably in the range of 5 to 2000000 mPa · s, more preferably 50 to 10000 mPa · s, and particularly preferably 100 to 50000 mPa · s. When the viscosity is lower than 5 mPa · s, and when the viscosity is higher than 2000000 mPa · s, emulsification is difficult and a stable emulsion cannot be obtained. further,

The content of the component (A) is 20 to 60 parts by mass when the total mass of the components (A) to (E) is 100 parts by mass. If it exceeds 60 parts by mass, the viscosity of the composition increases and the handleability may deteriorate. More preferably, it is 25 to 55 parts by mass.

The alkenyl group-containing polyorganosiloxane of the component (A) is produced by a method known to those skilled in the art, and is an acid catalyst such as sulfuric acid, hydrochloric acid, nitric acid, active clay, tris phosphite (2-chloroethyl), or Base catalysts such as lithium hydroxide, sodium hydroxide, potassium hydroxide, tetramethylammonium hydroxide, tetra-n-butylammonium hydroxide, tetra-n-butylphosphonium hydroxide, sodium silanolate, and potassium silanolate were used. It can be produced by condensation and / or ring-opening polymerization of chain and / or cyclic low molecular weight siloxane.

The component (A) may be a single component or a mixture of two or more kinds of components satisfying the above conditions.

(Component (B))
The component (B) is an organohydrogenpolysiloxane having an average composition formula represented by the general formula (2) and containing two or more hydrogen atoms having a silicon atom bond in one molecule, and is a cross-linking component with respect to the component (A). Is.
(Chemical 2)
R ³ _c H _d SiO _{(4-cd) / 2} (2)
In formula (2), R ³ is the same or different monovalent hydrocarbon group containing no aliphatic unsaturated group, c is 0.999 to 2.999, d is 0.001 to 2, and c + d is 1 to 3. Meet. As R ³ , ^{the hydrocarbon group exemplified in R 1} is used, preferably an alkyl group, and more preferably a methyl group. The number of hydrogen atoms bonded to the silicon atom of the component (B) is preferably 3 or more in one molecule.
The viscosity of this component (B) at 25 ° C. is usually 1 to 3000 mPa · s, preferably 5 to 500 mPa · s.
The content of the component (B) is 5 to 30 parts by mass when the total mass of the components (A) to (E) is 100 parts by mass. If it is less than 5 parts by mass, the component (A) is not sufficiently cured and the release film does not have sufficient strength, and if it exceeds 30 parts by mass, the viscosity of the composition increases and the handleability may deteriorate. In addition, there is a possibility that the SiH group becomes excessive and the unreacted cross-linking agent bleeds out after the release film is formed, causing some trouble. More preferably, it is 10 to 20 parts by mass.

The blending amount of the component (B) of the oil-in-water silicone emulsion composition of the present invention is one that is blended according to the number of alkenyl groups of the component (A), and the alkenyl bonded to the silicon atom of the component (A). The ratio of the number of groups (NA) to the number of hydrogen atoms bonded to the silicon atom of the component (B) is 1.0 ≦ (NE / NA) ≦ 6.0, preferably 1.5. The amount is adjusted so that ≦ (NE / NA) ≦ 4.0. If NE / NA is less than 1, curing of the composition does not proceed sufficiently, and unreacted alkenyl groups remain in the release agent layer, so that the release property tends to change over time. Further, when NE / NA exceeds 6, the releasability is enhanced by the organohydrogenpolysiloxane contrary to the intention of the present invention. The component (B) can be produced by those skilled in the art by a known method.

The component (B) may be a single component or a mixture of two or more kinds of components satisfying the above conditions.

The component (A) and the component (B) react with each other to form a cured silicone product. Therefore, usually, an emulsion having the composition of the component (A) alone and the component (C) or less and an emulsion having the composition of the component (B) alone and the component (C) or less are separately prepared and prepared as a kit. , It is preferable to mix these two liquids and apply them for use. However, it is also possible to prepare an emulsion by coexisting the component (A) and the component (B) from the beginning.

(Component (C))
The component (C) is a nonionic surfactant and plays a role of dispersing the components (A), (B) and the component (D) described later in water. Therefore, the oil-in-water silicone emulsion of the present invention. The composition can be provided. Nonionic surfactants having an HLB value of 8.0 to 19.0, which represents the balance between hydrophilicity and lipophilicity, are preferable, particularly 10.0 to 18.0, and even more preferably 10.0 to 16.0. is there. The HLB value is not particularly limited as long as it is a nonionic surfactant within the above range. If the HLB value of the surfactant used is not appropriate, even if emulsification is possible, storage stability and dilution stability are poor and sufficient performance cannot be exhibited. A surfactant having a low HLB value may be used in combination as another emulsifying aid.

Examples of such nonionic surfactants include sorbitan fatty acid ester, glycerin fatty acid ester, decaglycerin fatty acid ester, polyglycerin fatty acid ester, propylene glycol pentaerythritol fatty acid ester, polyoxyethylene sorbitan fatty acid ester, and polyoxyethylene sorbit fatty acid ester. , Polyoxyethylene glycerin fatty acid ester, polyethylene glycol fatty acid ester, polyoxyethylene alkyl ether, polyoxyethylene polyoxypropylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene castor oil, hardened castor oil, polyoxyethylene alkyl amine Examples thereof include fatty acid amide and polyalkyl glycol acid. These nonionic surfactants are also preferable in terms of safety, stability and price, and can be used alone or as a mixture of two or more kinds. In particular, polyoxyethylene alkyl ether is preferable from the viewpoint of emulsion stability. The content of the component (C) is 1 to 10 parts by mass when the total mass of the components (A) to (E) is 100 parts by mass. If it is less than 1 part by mass, it is difficult to disperse, and if it exceeds 10 parts by mass, the viscosity of the composition becomes high and the handleability becomes poor. More preferably, it is 3 to 6 parts by mass.

(Component (D))
The component (D) is a white metal-based catalyst, which is a hydrosilylation catalyst that catalyzes an addition reaction that occurs when the component (A) forms a crosslinked structure via the component (B). It is contained in an amount of 1 to 500 ppm, preferably 5 to 200 ppm, more preferably 20 to 100 ppm with respect to the weight of the component (A). If the content is less than 1 ppm, it takes a long time to cure, and the production efficiency of the release film coated with the oil-in-water silicone emulsion composition of the present invention may deteriorate. If it exceeds 500 ppm, the workable time of the composition is shortened, so that the workability may be reduced when the composition is applied to the film substrate.

The component (D) consists of a metal or a compound containing this metal. As the metal or a compound thereof, for example, a compound containing platinum, rhodium, palladium, ruthenium and iridium, preferably platinum or platinum can be used. Of these, platinum-based catalysts are particularly suitable because they have high reactivity. The metal may be fixed to a fine particle carrier material (eg, activated carbon, aluminum oxide, silicon oxide). The platinum compounds, platinum halides _{(e.g., PtCl 4, H 2 PtCl 4} · 6H 2 O, Na 2 PtCl 4 · 4H 2 O, H 2 PtCl 4 · 6H 2 O and the reaction products of cyclohexane) platinum -Olefin complex, platinum-alcohol complex, platinum-alcolate complex, platinum-ether complex, platinum-aldehyde complex, platinum-ketone complex, platinum-vinylsiloxane complex (eg, platinum-1,3-divinyl 1,1,3) 3-Tetramethyldisiloxane complex, bis- (γ-picolin) -platinum dichloride, trimethylenedipyridine-platinum dichloride, dicyclopentadiene-platinum dichloride, cyclooctadiene-platinum dichloride, cyclopentadiene-platinum dichloride), bis ( Examples thereof include an alkynyl) bis (triphenylphosphine) platinum complex and a bis (alkynyl) (cyclooctadien) platinum complex. The hydrosilylation catalyst can also be used in microencapsulated form. In this case, the fine particle solid containing the catalyst and insoluble in the organopolysiloxane is, for example, a thermoplastic resin (for example, a polyester resin or a silicone resin). The platinum-based catalyst can also be used in the form of clathrate compounds, for example, in cyclodextrin.

(Component (E))
The component (E) is water that serves as a dispersion medium when emulsifying the components (A) to (D). The water is not particularly limited, but it is preferable to use ion-exchanged water, preferably pH 2 to 12, and particularly preferably pH 4 to 10. The use of mineral water is not recommended, but when it is used, it is preferably used in combination with a metal deactivator or the like. When the total mass of the components to be dispersed is 100 parts by mass, an amount corresponding to 30 to 80 parts by mass, preferably 35 to 70 parts by mass is added.

The oil-in-water silicone emulsion composition of the present invention is not produced by simultaneously dispersing all of the above components (A) to (D) in the component (E), but among the above components (A) to (D). It is preferable to prepare a kit in which at least two or more kinds of components are dispersed in the component (E), and finally mix the kit as an oil-in-water silicone emulsion composition. If all the components (A) to (D) are dispersed in the component (E) at the same time, an addition reaction occurring between the components (A), (B), and (D) proceeds during the production of the composition. Therefore, the coating film cannot be formed. In the manufacturing method, for example, a kit in which the components (A), (C), and (D) are dispersed in the component (E) is produced, while the component (B) and the component (D) are separately separated into the component (E). One method is to prepare a dispersed kit and mix the two. The component (A) and the component (B) are the number of alkenyl groups (NA) bonded to the silicon atom of the component (A) in the final oil-in-water silicone emulsion composition regardless of the number of kits prepared. , The ratio of the component (B) to the number of hydrogen atoms bonded to the silicon atom (NE) is 1.0 ≦ (NE / NA) ≦ 6.0, preferably 1.5 ≦ (NE / NA). ) ≤ 4.0, and the component (C) must be 1 to 500 ppm, preferably 5 to 200 ppm, more preferably 20 to 120 ppm based on the weight of the component (A). It shall be prepared in the amount of In the oil-in-water silicone emulsion composition of the present invention, no matter how many kinds of components (A) to (D) are dispersed in the component (E) as a kit, the component (E) of the dispersion medium is water, so after all, it is a solvent type. It is an emulsion type composition that is different from the above and is considered for the influence on the environment and the human body.

A known method can be adopted as a method for dispersing the components (A) to (D) in the component (E). For example, a method of mixing and emulsifying the above components using a homogenizer, a colloid mill, a homomixer, a high-speed stator rotor agitator, or the like can be adopted. When the components (A) to (D) are dispersed in the component (E), specifically, a part of the component (E) is added to the components (A) to (D) and stirred to obtain an oil. After making the medium water type, if the remaining water is further added to make the oil-in-water type, the components (A) to (D) can be easily dispersed and the stability of the emulsion is improved.

The oil-in-water silicone emulsion composition of the present invention may contain components other than silicone, for example, an organic polymer or the like. If the desired conditions are satisfied, the desired coatability and peelability can be obtained. However, in order to obtain more sufficient coatability and peelability, it is preferable that the composition is mainly composed of silicone.

The oil-in-water silicone emulsion composition of the present invention is an adhesion improver for the purpose of improving adhesion to a substrate, a transition component for the purpose of adjusting peelability, or a transition component, as long as the object of the present invention is not impaired. It may contain an antiseptic for the purpose of antiseptic.
Such components include, for example, a general silane coupling agent for adhesion improvers, an oil-in-water silicone emulsion as a transition component, and sorbic acid, sorbate, acetic acid, lactic acid, benzoic acid, and salicylic acid as preservatives. Examples thereof include phenoxyethanol and formalin.

The cooling unit 24 includes a plate heat exchanger 26, a refrigerant temperature adjusting unit 28, and a temperature detecting unit 30, and a water-in-oil preemulsion generated at room temperature in the emulsification and dispersion unit 22 exchanges plate heat. Liquid is sent to the vessel 26, where the temperature is feedback-controlled by the refrigerant temperature adjusting unit 28 based on the temperature of the water-in-oil preemulsion after cooling detected by the temperature detecting unit 30. The water-type pre-emulsion is cooled to a predetermined temperature.
Here, the plate type heat exchanger 26 is a conventionally known one, and although detailed description thereof will be omitted, a plurality of heat transfer plates are arranged inside in parallel with each other at intervals, and are formed between the plates. The water-in-oil preemulsion is cooled by the refrigerant via the heat transfer plate by alternately flowing the refrigerant and the water-in-oil preemulsion in the flow path alternately in a facing manner or in parallel. I am trying to do it.
As the refrigerant to be used, for example, ethylene glycol and silicone oil are preferable because the cooling temperature is low.
The flow rate of the water-in-oil preemulsion to be fed to the plate heat exchanger 26 is adjusted so that innumerable water droplets in the oil content of the water-in-oil preemulsion do not freeze in the plate heat exchanger 26. I am trying to do it.
Thereby, for example, by storing the water-in-oil pre-emulsion in a cooling chamber controlled at a predetermined temperature, it is not necessary to keep the cold water, in other words, the oil-in-water type while saving energy and omitting extra steps. When producing an emulsion, the water-in-oil preemulsion at room temperature from the emulsification / dispersion unit 22 can be continuously cooled to a predetermined temperature and liquid-fed to the liquid crystal phase forming unit 14 on the downstream side, and later. As will be described, since the liquid crystal phase forming unit 14 also continuously forms the liquid crystal phase, the water-in-oil pre-emulsion generated in the water-in-oil pre-emulsion generation unit 12 is used continuously. It is possible to produce an oil-in-water emulsion.

As a modification, the heat exchanger provided in the cooling unit 24 is limited to the plate heat exchanger as long as the temperature of the pre-emulsion is achieved to be within a predetermined temperature range by the time it is supplied to the emulsification / dispersion unit 22. Instead, for example, a hose having a large surface surface or a static mixer having a spiral blade inside may be built in the jacket.

As shown in FIG. 2, the liquid crystal phase forming unit 14 is a liquid crystal phase forming container 36 having an inflow port 32 from the water-in-oil pre-emulsion generation unit 12 and an outflow port 34 to the oil-in-water type emulsion generation unit 16. It has a rotor 38 that can rotate about a central axis 37, a rotor 38, and a stator 40 that is concentrically arranged as an outer cylinder with a predetermined gap 39 (δ) separated from the rotor 38. A plurality of slits 42 are provided at predetermined angular intervals in the circumferential direction so that the water-in-oil preemulsion flows into the predetermined gap 39 and shear energy is applied before flowing out through the slits 42. .. δ is usually set to 1 to 2 mm. The shear rate is determined by adjusting the relationship between the peripheral speed of the rotor and δ. The value of the shear rate can define the shear energy to the material present in the gap.
The liquid crystal phase formation described here refers to both the formation of a liquid crystal lamella and the subsequent subdivision of the liquid crystal phase.
The central shaft 37 is connected to the motor 43, and the rotor 38 is configured to rotate around the central shaft 37 as shown by an arrow. However, the formed liquid crystal phase exerts the rotational force of the rotor 38. As a driving source, the liquid crystal phase forming container 36 is fed from the outlet 34 to the oil-in-water emulsion generating section 16 on the downstream side. The rotor 38 is solid. Further, a liquid crystal phase forming container outlet temperature measuring device 44 is installed so that the temperature of the effluent immediately after the completion of shear energy application can be measured in the liquid crystal phase forming container.

The combination of the rotor 38 and the stator 40 is arranged vertically in the liquid crystal phase forming container 36, the inflow port 32 is provided directly above the predetermined gap, and the outlet 34 is on the side surface of the liquid crystal phase forming container 36. The pre-emulsion provided and guided into the liquid crystal phase forming container 36 is not a circulation type but a passing type one-through method so that shear energy is applied between the time when the preemulsion directly flows into the predetermined gap and the time when the pre-emulsion flows out. For example, compared to the conventional technique in which shear energy is applied by a circulation method by rotating a shear blade provided in the container, shear energy is uniformly applied to the pre-emulsion without variation depending on the location in the container. It is possible to do.

More specifically, during the formation of liquid crystal lamella, which is a transition state between the water-in-oil pre-emulsion and the oil-in-water emulsion, the viscosity of the water-in-oil pre-emulsion rapidly increases with the formation of the liquid crystal lamella, and is sealed. The water-in-oil preemulsion that has flowed into the space is given shear energy by friction with the inner surface of the rotor 38 that rotates constantly until it flows out from the slit 42 of the stator 40, but the viscosity increases. As a result, the shear energy given per hour increases.

Here, although it is presumed, in the present invention, the mechanism at which the liquid crystal lamella is formed and grown in the preferable cooling temperature range of the preemulsion of −40 ° C. to −5 ° C. It is described below whether it can be confirmed as such.
At the stage where the pre-emulsion is prepared at room temperature, it is considered that a state in which the oil phase becomes a continuous phase is mainly formed. In short, it is a water-based emulsion in oil, but even if it does not take the form, the continuous phase of the oil phase can prevent the entire preemulsion from freezing, so liquid crystal lamella formation Is considered to meet the requirements for.
As shown in FIG. 3, when the pre-emulsion is cooled in the above temperature range, a structure in which the surfactant repeats alternately with the water layer in a layered state (or other shape) is formed as shown in FIG. 3A. It is thought that it will be done. So to speak, it is considered that a precursory framework of liquid crystal lamella is formed.
When shearing is started in that state, it is considered that oil is inserted between the layers of the above framework. It is the state of (b) of FIG. 3, and this is a liquid crystal lamella. When this state is formed, the viscosity of the system increases, so that it can be confirmed that the liquid crystal lamella is formed. The ability of lamellas to be inserted between layers even at such low temperatures is deeply related to the essence of silicone. Since the main chain of silicone is easy to rotate freely, it has a low glass transition point and can maintain fluidity even at a lower temperature than a normal organic polymer. In particular, silicone can maintain fluidity even at a low temperature such as -25 ° C. and can form a fine phase-separated structure such as liquid crystal lamella by interaction with a surfactant and water. Therefore, at a low temperature such as -25 ° C, the formation of liquid crystal lamella, which is completely impossible with ordinary organic polymers, is possible with silicone.
Here, both the width d of the water layer and the width d'of the oil layer per layer of the lamella become smaller because the cohesiveness of the lamella increases as the cooling temperature decreases, that is, the spacing between the layers of the liquid crystal lamella. Is considered to be smaller, which is thought to lead to a smaller particle size of the final oil-in-water emulsion.
As shown in FIG. 3C, in order for the liquid crystal lamella to grow, activation energy accompanied by endothermic heat and frictional heat due to an increase in viscosity occur. Details are given in the paragraph below.

On the other hand, as shown in FIG. 4, activation energy is required for the water-in-oil preemulsion to form a liquid crystal lamella, and the required activation energy is the temperature of the water-in-oil preemulsion. The lower the value, the more it tends to increase.
Therefore, at the stage of forming the liquid crystal lamella and the subdivided liquid crystal phase, the constant rotation speed of the rotor 38 is selected, and at the time when the formation of the subdivided liquid crystal phase is completed, the temperature of the subdivided liquid crystal phase becomes equal to or lower than the selected temperature. First, by cooling the water-in-oil pre-emulsion to a predetermined temperature in the production stage of the water-in-oil pre-emulsion according to the ratio of the amount of the surfactant to the amount of oil, the water in oil at room temperature Compared to the case of forming a liquid crystal lamella using a type pre-emulsion, the temperature rise at the completion of the formation of the subdivided liquid crystal phase is suppressed. Second, the water-in-oil pre-emulsion is cooled to a predetermined temperature. As a result, the initial viscosity at the start of liquid crystal lamella formation increases, which increases the activation energy required for liquid crystal lamella formation. Third, by selecting a constant number of rotations of the rotor 38, in a closed space. The heating time of the liquid crystal lamella is selected, and the generated shear energy increases due to the increase in the initial viscosity at the start of liquid crystal lamella formation. From the above, the closed space is selected by selecting the cooling temperature of the water-in-oil preemulsion. Small-scale structure by balancing the shear energy applied to the water-in-oil preemulsion with the activation energy required for liquid crystal lamella formation through the suppression of extra heating of the formed liquid crystal lamella. The temperature at the time when the formation of the liquid crystal phase is completed is set to a desired temperature, so that the particle size of the oil droplets of the oil-in-water emulsion can be adjusted.

Since the activation energy can change depending on the combination of the oil and the surfactant, some trial and error is required, but due to the lowering of the temperature of the pre-emulsion, the pre-emulsion during the formation of the liquid crystal lamella is compared with the case where the temperature is not lowered. By lowering the initial temperature of the emulsion and increasing the activation energy, it is possible to suppress the temperature rise of the liquid crystal phase when the formation of the subdivided liquid crystal phase is completed.
For example, it is preferable to determine the opening area of the slits, the angular distance between the slits adjacent to each other in the circumferential direction, and the size of the gap from such a viewpoint.

Next, the oil-in-water emulsion generation unit 16 has a conventionally known emulsification / dispersion device similar to the water-in-oil preemulsion generation unit 12 and the liquid crystal phase forming unit 14, and in the emulsification / dispersion device, the liquid crystal phase forming unit 14 Water for dilution is added to the liquid crystal phase formed in (1) to induce a phase inversion to form an oil-in-water emulsion. The flow rate of the water for dilution is adjusted according to the state of the liquid crystal phase to which the water for dilution is added.
The continuously produced oil-in-water emulsion is appropriately stored in a tank.

As described above, when a water-in-oil preemulsion is usually produced at room temperature, the surfactant is polarized into a hydrophilic group and a hydrophobic group and exists at the interface between the oil phase and the aqueous phase. Where the excess surfactants combine to form a micelle structure, by lowering the temperature of the water-in-oil preemulsion to, for example, -25 ° C, the surfactant can be more than such a micelle structure. However, since a structure with a strong degree of association is formed, when the low-temperature oil-in-water pre-emulsion is used as a liquid crystal lamella, the required activation energy is increased as compared with the oil-in-oil pre-emulsion at room temperature. Therefore, in the liquid crystal lamella formation stage, the energy consumed as activation energy increases with respect to the applied shear energy, and the temperature of the water-in-oil preemulsion when the shear energy is applied is low. In combination with this, it is possible to effectively prevent the temperature rise of the formed liquid crystal phase and suppress the expansion of the diameter of the oil droplet particles of the oil-in-water emulsion due to the temperature rise, as well as in the oil. By adjusting the lowering temperature of the water-type pre-emulsion, it is possible to adjust the particles of the oil droplets of the water-based oil-type emulsion.
In particular, by keeping the rotation speed of the rotor 38 in the liquid crystal phase forming portion 14 constant, the shear energy given to the water-in-oil preemulsion in the closed space increases as the viscosity increases, but the liquid crystal phase forming portion Adjusting the particle size of the oil droplets of the oil-in-water emulsion by setting the number of rotations of the rotor 38 to be kept constant in relation to the temperature of the water-in-oil preemulsion that is lowered when flowing into 14. At the same time, it is also possible to suppress the spread of the particle size distribution of the oil droplets by limiting the non-uniformity of the liquid crystal phase formed due to the fluctuation of the shear rate (rotational speed of the rotor 38).

As a modification, in particular, when a water-in-water emulsion is continuously produced from a water-in-oil emulsion by a liquid crystal emulsification method, it is necessary to form a liquid crystal lamella by lowering the temperature of the water-in-oil emulsion (pre-emulsion). By increasing the active energy, the temperature rise of the liquid crystal lamella formed based on the shear energy applied to the pre-emulsion is suppressed, thereby increasing the particle size of the oil droplets in the oil-in-water emulsion. The required activation energy and the applied shear are not only suppressed, but also the temperature of the water-in-oil emulsion (pre-emulsion) is lowered, and the shear energy applied to the pre-emulsion is also reduced. By adjusting both energies, it is possible not only to suppress the increase in the particle size of the oil droplets in the oil-in-water emulsion, but also to adjust the particle size of the oil droplets.

In this case, by lowering the temperature of the water-in-oil emulsion (pre-emulsion), the initial viscosity when the pre-emulsion is liquefied increases, so that the flow rate required for continuously producing the oil-in-water emulsion. Since it is difficult to secure, the temperature of the water-in-oil emulsion (pre-emulsion) is lowered within the range where the flow rate can be secured, while the required activation energy and the applied shear are reduced by reducing the applied energy. By balancing with energy, it is possible to adjust the particle size of the oil droplets.
For example, when applying shear energy to a pre-emulsion in a predetermined gap between a rotating rotor and a stator type, the applied shear energy can be increased or decreased by adjusting the rotation speed of the rotor.

The lower the cooling temperature of the pre-emulsion, that is, the temperature of the liquid crystal lamella, the lower the temperature of the subdivided liquid crystal phase, that is, the temperature of the emulsion at the time of leaving the emulsifier, but the temperature rises, that is, the liquid crystal lamella. The difference between the temperature of the emulsion and the temperature of the emulsion at the time of leaving the emulsifier becomes large.
For example, when the temperature of the liquid crystal lamella is −25 ° C., the temperature of the emulsion at the time of leaving the emulsifier is 30 ° C. When the former temperature is 20 ° C, the latter temperature is 60 ° C.
The reason for this is presumed as follows.
The temperature at which the liquid crystal lamella collapses and is subdivided into fine liquid crystal phases is considered to be constant regardless of the temperature at which the liquid crystal phase is generated, and is considered to be in the range of −5 ° C. to 40 ° C.
In this temperature range, the liquid crystal phase is subdivided by an endothermic reaction. At that time, since the liquid crystal phase generated at a lower temperature has a larger activation energy for forming the liquid crystal phase, the degree of endothermic process is larger. Therefore, within the subdivision temperature range, the degree to which the shear energy given from the outside is absorbed is greater when the liquid crystal phase formation temperature is lower.
However, until the temperature rises to -5 ° C, when the liquid crystal begins to subdivide, the shear energy given is not used for liquid crystal subdivision, but is dissipated as frictional heat and exchanges heat with the outside air. , The system rises to 25 ° C.
Therefore, when shearing is applied to the liquid crystal phase generated at an extremely low temperature such as −25 ° C., the temperature rises up to 25 ° C., so that the degree of the temperature rise becomes large.
On the other hand, the liquid crystal phase generated at a higher temperature such as 20 ° C. has a small activation energy for formation, so that the degree of endothermic for subdivision is small, and the temperature is 50 ° C., that is, the subdivision of the liquid crystal phase is It will exceed the ending temperature. At 50 ° C. or higher, the temperature becomes higher due to the influence of frictional heat and the like.

In cooling the pre-emulsion, it is necessary to avoid freezing of the water alone, the surfactant alone, or the water and the surfactant in the middle of the formation of the liquid crystal lamella. This is because when frozen, oil cannot enter between the layers of water and surfactant. Therefore, it is preferable to cool the water-in-oil emulsion, which is a pre-emulsion, after the production is completed. In this way, at a predetermined cooling temperature, a desired liquid crystal lamellar structure, that is, a continuous structure of three layers of an aqueous layer, a surfactant layer, and an oil layer can be obtained.
However, if it is possible to prevent the water alone, the surfactant alone, or the moisture and the surfactant from freezing in advance, the temperature may be lowered from the temperature at the time of production, or the water-in-oil emulsion may be produced during production. The temperature may be lowered. It suffices that the set cooling temperature is reached at the time when the formation of the liquid crystal lamella is finally completed. However, if cooling is started during or during the production of the pre-emulsion, the liquid crystal lamella may start to form in a state where the composition is unevenly distributed, and the finally formed liquid crystal lamella may not be uniform. In this sense as well, it is preferable to cool the water-in-oil emulsion after the production is completed.

The applicant is a test for measuring the particle size of oil droplets of the produced oil-in-water emulsion using the oil-in-water emulsion production system 10 described in the embodiment with the temperature of the water-in-oil preemulsion as a parameter. Was done.
Table 1 shows the composition, conditions, and results of the emulsions used in each Example and Comparative Example.

<Example 1>
As the component (A), 50 parts by mass of an organopolysiloxane having a methyl group and a vinyl group and having a viscosity at 25 ° C. of 5,000 mPa · s, and as a component (C), 5 nonionic surfactants. As the component (D) with 0.0 parts by mass, the ratio of the amount of the nonionic surfactant to the amount of oil was set to 0.1.
Further, 100 parts by mass of a water-in-oil preemulsion was prepared by using a platinum catalyst at 100 ppm with respect to the component (A) and purified water as the component (E) as the balance. The initial viscosity immediately after the preparation of this pre-emulsion was 6,000 mPa · s (25 ° C., 10s ^-1 ).
The preemulsion was cooled at -25 ° C and stored until the overall temperature was constant. On the other hand, ^{at a shear rate of 2,000 s-1} , the liquid crystal phase forming container, which is a closed space, is allowed to flow into the rotor / stator, and the residence time is 0.06 seconds between the share gaps. I let it pass so that it would be. In a simulated device capable of producing the same conditions as the above manufacturing conditions, 0.03 seconds after the addition of the shear rate, gelation occurred and the fluidity was lost (viscosity measurement impossible). The degree of gelation was great. The temperature at the outlet of the liquid crystal phase forming container was 25 ° C.
The oil-in-water emulsion was prepared by passing through the rotor / stator, and then further charged into a connected rotor / stator type emulsifier together with a certain amount of water to prepare an oil-in-water emulsion.
The average particle size of the emulsion particles of the obtained oil-in-water emulsion was measured and found to be 0.20 μm.

<Example 2>
52.5 parts by mass of organopolysiloxane having a methyl group and a vinyl group as the component (A) and a viscosity at 25 ° C. of 5,000 mPa · s, and a nonionic surfactant as the component (C). The amount ratio of the nonionic surfactant to the amount of oil was set to 0.05 with 2.5 parts by mass and the component (D).
Further, 100 parts by mass of a water-in-oil preemulsion was prepared by using a platinum catalyst at 100 ppm with respect to the component (A) and purified water as the component (E) as the balance. The initial viscosity of this pre-emulsion immediately after preparation was 6,100 mPa · s (25 ° C., 10s ^-1 ).
The preemulsion was cooled at -25 ° C and stored until the overall temperature was constant. On the other hand, ^{at a shear rate of 2,000 s-1} , the liquid crystal phase forming container, which is a closed space, is allowed to flow into the rotor / stator, and the residence time is 0.06 seconds between the share gaps. I let it pass so that it would be. In a simulated device capable of producing the same conditions as the above manufacturing conditions, 0.03 seconds after the addition of the shear rate, gelation occurred and the fluidity was lost (viscosity measurement impossible). The degree of gelation was great. The temperature at the outlet of the liquid crystal phase forming container was 30 ° C.
The oil-in-water emulsion was prepared by passing through the rotor / stator, and then further charged into a connected rotor / stator type emulsifier together with a certain amount of water to prepare an oil-in-water emulsion.
The average particle size of the emulsion particles of the obtained oil-in-water emulsion was measured and found to be 0.20 μm.

<Example 3>
As the component (A), 50 parts by mass of an organopolysiloxane having a methyl group and a vinyl group and having a viscosity at 25 ° C. of 5,000 mPa · s, and as a component (C), 5 nonionic surfactants. As parts by mass and component (D), the ratio of the amount of the nonionic surfactant to the amount of oil was set to 0.1.
Further, 100 parts by mass of a water-in-oil preemulsion was prepared by using a platinum catalyst at 100 ppm with respect to the component (A) and purified water as the component (E) as the balance. The initial viscosity immediately after the preparation of this pre-emulsion was 6,000 mPa · s (25 ° C., 10s ^-1 ).
The preemulsion was cooled at −10 ° C. and stored until the overall temperature was constant. On the other hand, ^{at a shear rate of 2,000 s-1} , the liquid crystal phase forming container, which is a closed space, is allowed to flow into the rotor / stator, and the residence time is 0.06 seconds between the share gaps. I let it pass so that it would be. In a simulated device capable of producing the same conditions as the above manufacturing conditions, 0.03 seconds after the addition of the shear rate, gelation occurred and the fluidity was lost (viscosity measurement impossible). The degree of gelation was medium. The temperature at the outlet of the liquid crystal phase forming container was 25 ° C.
The oil-in-water emulsion was prepared by passing through the rotor / stator, and then further charged into a connected rotor / stator type emulsifier together with a certain amount of water to prepare an oil-in-water emulsion.
The average particle size of the emulsion particles of the obtained oil-in-water emulsion was measured and found to be 0.22 μm.

<Comparative example 1>
As the component (A), 50 parts by mass of an organopolysiloxane having a methyl group and a vinyl group and having a viscosity at 25 ° C. of 5,000 mPa · s, and as a component (C), 5 nonionic surfactants. As parts by mass and component (D), the ratio of the amount of the nonionic surfactant to the amount of oil was set to 0.1.
Further, 100 parts by mass of a water-in-oil preemulsion was prepared by using a platinum catalyst at 100 ppm with respect to the component (A) and purified water as the component (E) as the balance. The initial viscosity immediately after the preparation of this pre-emulsion was 6,000 mPa · s (25 ° C., 10s ^-1 ).
The preemulsion was cooled (or kept warm) at 20 ° C. and stored until the overall temperature was constant. On the other hand, ^{at a shear rate of 2,000 s-1} , the liquid crystal phase forming container, which is a closed space, is allowed to flow into the rotor / stator, and the residence time is 0.06 seconds between the share gaps. I let it pass so that it would be. In a simulated device capable of producing the same conditions as the above manufacturing conditions, 0.03 seconds after the addition of the shear rate, gelation occurred and the fluidity was lost (viscosity measurement impossible). The degree of gelation was small. The temperature at the outlet of the liquid crystal phase forming container was 60 ° C.
The oil-in-water emulsion was prepared by passing through the rotor / stator, and then further charged into a connected rotor / stator type emulsifier together with a certain amount of water to prepare an oil-in-water emulsion.
The average particle size of the emulsion particles of the obtained oil-in-water emulsion was measured and found to be 0.30 μm.

<Comparative example 2>
As component (A), 54 parts by mass of organopolysiloxane having a methyl group and a vinyl group and having a viscosity at 25 ° C. of 5,000 mPa · s, and as component (C), 1 nonionic surfactant. As parts by mass and component (D), the ratio of the amount of the nonionic surfactant to the amount of oil was set to 0.1.
Further, 100 parts by mass of a water-in-oil preemulsion was prepared by using a platinum catalyst at 100 ppm with respect to the component (A) and purified water as the component (E) as the balance. The initial viscosity of this pre-emulsion immediately after preparation was 6,200 mPa · s (25 ° C., 10s ^-1 ).
The preemulsion was cooled at −10 ° C. and stored until the overall temperature was constant. On the other hand, ^{at a shear rate of 2,000 s-1} , the liquid crystal phase forming container, which is a closed space, is allowed to flow into the rotor / stator, and the residence time is 0.06 seconds between the share gaps. I let it pass so that it would be. In a simulated device capable of producing the same conditions as the above manufacturing conditions, 0.03 seconds after the addition of the shear rate, gelation occurred and the fluidity was lost (viscosity measurement impossible). The degree of gelation was medium. The temperature at the outlet of the liquid crystal phase forming container was 45 ° C.
The oil-in-water emulsion was prepared by passing through the rotor / stator, and then further charged into a connected rotor / stator type emulsifier together with a certain amount of water to prepare an oil-in-water emulsion.
The average particle size of the emulsion particles of the obtained oil-in-water emulsion was measured and found to be 0.28 μm.

The following can be derived from the results of each Example and Comparative Example.
1. 1. In both Examples and Comparative Examples, after 0.03 seconds of shearing the pre-emulsion, the viscosity increased to an unmeasurable level, gelled and lost fluidity, and finally became non-gelled, producing an oil-in-water emulsion. Therefore, it is inferred that liquid crystal lamella was formed in the liquid crystal phase forming container.
2. In Examples 1 to 3, the temperature of the liquid crystal phase forming container was less than 40 ° C., and the average particle size of the obtained oil-in-water emulsion was preferably 0.20 to 0.22 μm. On the other hand, in Comparative Examples 1 and 2, the temperature of the liquid crystal phase forming container exceeded 40 ° C., and the average particle size of the obtained oil-in-water emulsion was 0.28 to 0.30 μm, which was an unfavorable diameter. In each example, it is suggested that the endothermic reaction associated with the fragmentation of the liquid crystal phase was maintained.
3. 3. In the comparison between Example 1 (the amount ratio of the surfactant to the oil content 0.1) and Example 2 (the amount ratio of the surfactant to the oil content 0.05), the cooling temperature of the pre-emulsion was also -25 ° C. However, the outlet temperature of the liquid crystal phase forming container was 25 ° C. in Example 1 and 30 ° C. in Example 3. Since the degree of gelation in Examples 1 and 2 was greater than that in Example 3 0.03 seconds after shear addition, it is presumed that frictional heat was generated more. However, since the outlet temperature of the liquid crystal phase forming container was less than 40 ° C. in both Examples 1 and 3, the endothermic reaction due to the subdivision of the liquid crystal was maintained, so that the diameter did not increase. Moreover, since the cooling temperature of the pre-emulsion was the same, the average particle size was the same.
4. In a comparison between Example 1 (pre-emulsion cooling temperature -25 ° C) and Example 3 (pre-emulsion cooling temperature -20 ° C) having the same pre-emulsion composition, the average particle size was 0 in Example 1. It was 20 μm, and in Example 3, it was 0.22 μm. Since the temperature of the liquid crystal phase forming container was also 25 ° C. in both Examples 1 and 3, it was found that the lower the cooling temperature of the pre-emulsion, the smaller the average particle size.
This is because the cohesiveness of the liquid crystal lamella increases as the temperature decreases on the premise that the increase in the particle size of the oil content of the oil-in-water emulsion due to excessive heating in the liquid crystal phase forming container is suppressed. The width of the oil layer becomes smaller, and the particle size of the oil content of the oil-in-water emulsion formed on the basis of this becomes smaller. In other words, by setting the pre-emulsion cooling temperature, the oil-in-water emulsion is formed through the liquid crystal lamella. It is inferred that it may affect the particle size of the oil content of the emulsion.
5. In Comparative Example 1, the composition of the pre-emulsion was the same as that of Example 1, but the temperature at the outlet of the liquid crystal phase forming container was 60 ° C. because the cooling (heat retention) temperature of the pre-emulsion was 20 ° C. It is considered that the endothermic reaction of the subdivision of the liquid crystal phase was not maintained and the temperature rose, which caused the diameter to increase.
6. In Comparative Example 2, the ratio of the amount of the surfactant to the oil content was 0.02. The cooling temperature of the pre-emulsion was -10 ° C, but the outlet temperature of the liquid crystal phase forming container rose to 45 ° C, which is considered to have caused the diameter to increase. It is suggested that the cooling temperature of the pre-emulsion needs to be set according to the ratio of the amount of the surfactant to the oil content.

Although the embodiments of the present invention have been described in detail above, those skilled in the art can make various modifications or changes within the scope of the present invention.
For example, in the present embodiment, the liquid crystal phase forming portion 14 has been described as a continuous type, but the liquid crystal phase forming portion 14 is not limited to the continuous type, and the temperature of the liquid crystal phase accompanying the application of excess shear energy in the liquid crystal phase forming portion 14 is not limited thereto. As long as there is a possibility of rising, a batch type, for example, a water-in-oil preemulsion may be stored in an open container and shear energy may be applied by repeating circulation.
For example, in the present embodiment, the rotor has been described as a tubular structure that forms a predetermined gap with the stator, but the rotor is not limited to this, and shear energy can be applied to the liquid crystal phase forming portion 14. As long as it is, for example, a plurality of rotor blades may be provided on the outer peripheral surface at predetermined angular intervals, or a concave groove may be cut.

It is an overall schematic view of the oil-in-water emulsion production system 10 which concerns on embodiment of this invention. It is the schematic which shows the main part of the liquid phase emulsification apparatus of the liquid crystal phase forming part 14 of the oil-in-water emulsion production system 10 which concerns on embodiment of this invention. FIG. 5 is a conceptual diagram showing the formation and growth of a liquid crystal lamella by lowering the temperature of a water-in-oil preemulsion in the liquid crystal phase forming portion 14 of the oil-in-water emulsion manufacturing system 10 according to the embodiment of the present invention. It is a relationship diagram which shows the cooling temperature of a pre-emulsion and the temperature rise after the start of shearing in the liquid crystal phase forming part 14 of the oil-in-water emulsion production system 10 which concerns on embodiment of this invention.

10 Submersible oil type emulsion production system 12 Submersible oil type pre-emulsion generation unit 14 Liquid crystal phase forming unit 16 Submersible oil type emulsion generation unit 18 Piping 20 Liquid feed pump 22 Emulsification dispersion unit 24 Cooling unit 26 Plate type heat exchanger 28 Coolant temperature Adjusting unit 30 Temperature detection unit 32 Inflow port 34 Outlet 36 Liquid crystal phase forming container 37 Central axis 38 Rotor 39 Predetermined gap 40 Stator 42 Slit 43 Motor 44 Liquid crystal phase forming container outlet Temperature measuring instrument

Claims (6)

A liquid crystal emulsification method for continuously producing an oil-in-water emulsion via a liquid crystal phase using a water-in-oil preemulsion of a silicone composition and a nonionic surfactant.
At the stage of producing a water-in-oil preemulsion by selecting the ratio of the amount of nonionic surfactant to the amount of oil,
By applying shear energy to the water-in-oil pre-emulsion in the closed space until the water-in-oil pre-emulsion at a predetermined flow rate flows into the closed space and flows out of the closed space, the oil-in-water emulsion can be produced. The stage of forming the liquid crystal phase so that it is ready for formation,
It has a stage of forming an oil-in-water emulsion by adding water to the liquid crystal phase flowing out of the closed space.
The ratio of the amount of surfactant to the amount of oil in the production stage of the water-in-oil preemulsion so that the heat absorption reaction due to the liquefaction of the water-in-oil preemulsion does not end when the liquid crystal phase flows out of the closed space. A method for continuously producing an oil-in-water emulsion, which comprises setting the temperature of the water-in-oil preemulsion according to the above. A liquid crystal emulsification method for continuously producing an oil-in-water emulsion via a liquid crystal phase using a water-in-oil preemulsion of a silicone composition and a nonionic surfactant.
At the stage of producing a water-in-oil preemulsion by selecting the ratio of the amount of nonionic surfactant to the amount of oil,
A liquid crystal composed of a liquid crystal lamella by applying shear energy to the water-in-oil preemulsion in the closed space until a predetermined flow rate of the water-in-oil preemulsion flows into the closed space and flows out from the closed space. As well as forming a phase
The stage of adjusting the cohesiveness of the liquid crystal lamella,
The stage of subdividing the formed liquid crystal phase and
It has a stage of forming an oil-in-water emulsion by adding water to the subdivided liquid crystal phase flowing out of the closed space.
The water-in-oil preemulsion so that when the liquid crystal phase flows out of the closed space, the formed liquid crystal phase is settled in the subdivision stage and has a cooling temperature that determines the cohesiveness of the liquid crystal lamella. A method for continuously producing an oil-in-water emulsion, which comprises a step of cooling the water-in-oil preemulsion to a predetermined temperature according to the ratio of the amount of the surfactant to the amount of oil. The stage of applying shear energy includes a rotor that can rotate about a central axis and a stator that is concentrically arranged as an outer cylinder with a predetermined gap between the rotor and the rotor, and the stator has a predetermined angle in the circumferential direction. The first or second aspect, wherein a plurality of slits are provided at intervals, and a step of applying shear energy before the water-in-oil preemulsion flows into a predetermined gap and flows out through the slits. The method for continuously producing an oil-in-water emulsion according to the above method. The method for continuously producing an oil-in-water emulsion according to claim 3, further comprising a step of maintaining a constant rotation speed of the rotor until the water-in-oil preemulsion flows into the closed space and flows out. The method for continuously producing an oil-in-water emulsion according to claim 4, wherein the rotation speed of the rotor is set according to the set temperature of the water-in-oil preemulsion. Claimed, wherein the temperature of the liquid crystal phase at a water content of 5% by mass or less is set in a temperature range of −40 ° C. to −5 ° C. depending on a desired diameter of oil droplets of an oil-in-water emulsion. The method for continuously producing an oil-in-water emulsion according to any one of Items 1 to 5.

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