JPH0633333B2 - Method for producing organopolysiloxane emulsion - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing an organopolysiloxane emulsion which can be suitably used as a release agent, a polish, a water repellent, a fiber treatment agent, a defoaming agent, cosmetics and the like. Regarding

2. Description of the Related Art Conventionally, an organopolysiloxane emulsion has a wide range of applications as described above and various production methods are known. Among them, an emulsion polymerization method is a method for obtaining a stable emulsion. The high degree of polymerization organopolysiloxane emulsion produced in (1) is usually called an organopolysiloxane latex.

As a method for producing the organopolysiloxane latex,
For example, a method of adding a catalyst selected from the group consisting of a strong acid and a strong alkali to an aqueous emulsion of an organosiloxane described in JP-B-34-2041 and polymerizing or copolymerizing until a desired increase in viscosity is obtained. 41-
Unit formula RnSiO described in Japanese Patent No. 13995
_{4-n / 2} organosiloxane and general formula HO (R) ₂
A method for emulsion-polymerizing a compound selected from silcarban having SiQSi (R) ₂ OH in the presence of an aliphatic-substituted benzenesulfonic acid, an aliphatic sulfonic acid, an aliphatic-substituted diphenyl ether sulfonic acid, etc., as a catalyst for emulsion polymerization. The octaorganocyclotetrasiloxane described in JP-A-43-18800 is emulsion-polymerized with alkyl hydrogen sulfate (alkyl hydrogen sulfate),
A method for producing an organopolysiloxane latex to be neutralized, a method for emulsion-polymerizing an organopolysiloxane described in Japanese Patent Publication No. 46-41038, and a salt-type method described in Japanese Patent Publication No. 54-19440. The unit formula R in an aqueous solution of an anionic surfactant
The organosiloxane having aSiO _{4-a / 2} is emulsified and then this emulsion is contacted with an acid type cation exchange resin to convert the salt type anionic surfactant to the acid type to bring the emulsion to a pH value below 4. A method has been proposed in which the polymerization of the organosiloxane is initiated by using the acid medium, and the polymerization or copolymerization is performed until a desired increase in viscosity is obtained.

For the mechanism of emulsion polymerization, see J. SAAM
And D. HUEBNER is the Journal of Polymer Science (Journal of Polymer)
Science); Polymer Chemist
ry Edition, Vol. 20, 3351-33
68 (1982), which discloses that when a cyclic siloxane such as dimethylcyclosiloxane is emulsion-polymerized with a strong acid such as dodecylbenzenesulfonic acid,
The cyclic siloxane undergoes ring-opening polymerization to give a general formula HO (Me ₂ Si
It is said that a siloxane oligomer represented by (O) _n H (n35) is produced, and this undergoes a polycondensation reaction to increase the degree of polymerization and an aqueous latex of dimethylpolysiloxane is produced. In this case, the terminal group of dimethylpolysiloxane in the latex produced becomes highly polymerized while being blocked by the terminal silanol group, and an equilibrium reaction between the silanol group and water occurs. It is said that it is determined by the water vapor pressure, that is, the temperature during emulsion polymerization. Although the viscosity of dimethylpolysiloxane in the latex thus produced varies depending on the polymerization temperature, it varies from several hundred thousand cs (centistokes) to several million c.
A wide range of latexes up to s or more of raw rubber can be obtained.

Further, as a method for controlling the viscosity of the diorganopolysiloxane in the emulsion, there is generally known a method of introducing a siloxane having a terminal blocking group at the time of emulsion polymerization to carry out emulsion polymerization of a cyclic siloxane and a siloxane having a terminal blocking group in a micelle. As a result, an organopolysiloxane emulsion having a desired viscosity can be produced.

However, in the conventional method, in order to produce an organopolysiloxane emulsion having a desired viscosity, a mixture of a cyclic siloxane and a siloxane having a terminal blocking group is simultaneously emulsified during emulsion dispersion, A general method is to carry out a polycondensation reaction in the same micelle to produce a desired emulsion. In this case, the molecular weight and viscosity of the organopolysiloxane in the obtained emulsion are determined during emulsification.

Therefore, when obtaining emulsions of organopolysiloxanes having different viscosities and molecular weights, it is necessary to prepare emulsions according to the desired viscosity and molecular weight each time, which is troublesome.

The present invention has been made in view of the above circumstances, and emulsion preparation can be carried out separately from emulsion polymerization, and the prepared emulsion can be used for the production of emulsions of organopolysiloxane having mutually different viscosities and molecular weights. Therefore, it is an object of the present invention to provide a method for producing an organopolysiloxane emulsion which is improved in productivity and industrially advantageous.

Means and Actions for Solving the Problems The present inventor has conducted extensive studies to achieve the above-mentioned object, and found that the emulsion polymerization reaction is not necessarily carried out only in micelles, but also in micelles. Then, an emulsion of the cyclic organosiloxane of the general formula (I) described below and an emulsion of the chain organosiloxane of the general formula (II) having an end-capping group described below are separately prepared in advance using a surfactant for emulsion polymerization. Then, it was found that organopolysiloxane emulsions having various viscosities can be produced by mixing both emulsions at an arbitrary ratio and then emulsion-polymerizing the emulsions. Therefore, when producing organopolysiloxane emulsions having mutually different viscosities, it suffices to simply change the mixing ratio of the cyclic organosiloxane emulsion and the chain organosiloxane emulsion, and each of the above emulsions, once prepared, Since it can be used to produce an organopolysiloxane emulsion having various viscosities, it is possible to save the trouble of preparing an emulsion each time the organopolysiloxane emulsion is synthesized, and to mix the above-mentioned emulsions with an organopolysiloxane emulsion having an arbitrary viscosity. The inventors have found that an emulsion can be efficiently produced only by emulsion polymerization, and have completed the present invention.

Therefore, the present invention provides the following general formula (I) in an aqueous solution containing a surfactant for emulsion polymerization. (Wherein R ¹ and R ² are each a hydrogen atom or the same or different substituted or unsubstituted monovalent hydrocarbon group, and n is an integer of 3 to 6). In the aqueous solution containing the emulsion A emulsion-dispersed and the surfactant for emulsion polymerization, the following general formula (II) (However, in the formula, R ³ , R ⁴ , R ⁵ , and R ⁶ are each a hydrogen atom or the same or different substituted or unsubstituted monovalent hydrocarbon group, and m is an integer of 0 to 20). An organopolysiloxane emulsion characterized by separately preparing an emulsion B in which a chain-like organosiloxane having an end-capping group shown below is emulsified and dispersed, and then emulsion A and emulsion B are mixed and emulsion-polymerized. A method for manufacturing the same is provided.

Hereinafter, the present invention will be described in more detail.

The cyclic organosiloxane used in the present invention has the following formula (I): It is shown by.

Here, R ¹ and R ² are a hydrogen atom or a substituted or unsubstituted monovalent hydrocarbon group, specifically, a hydrogen atom,
Alkyl group such as methyl group, ethyl group, propyl group, alkenyl group such as vinyl group, allyl group, aryl group such as phenyl group, xenyl group, naphthyl group, cycloalkyl group such as silokuhexyl group, cyclo group such as cyclohexenyl group Aralkyl groups such as alkenyl groups, tolyl groups, and xylyl groups, and chloromethyl groups, trifluoropropyl groups, and cyanoethyl groups in which some or all of the hydrogen atoms bonded to the carbon atoms of these groups are replaced with halogen atoms, cyano groups, etc. Base,
Furthermore, an amino group, an epoxy group, a mercapto group, etc. are illustrated.

Further, the chain organosiloxane having a terminal blocking group used in the present invention is represented by the following general formula (II) It is shown by.

Here, R ³ , R ⁴ and R ⁵ are substituted or unsubstituted monovalent hydrocarbon groups, for example, alkyl groups such as methyl group, ethyl group and propyl group, alkenyl groups such as vinyl group and allyl group, Aryl groups such as phenyl group, xenyl group, naphthyl group, cycloalkyl groups such as cyclohexyl group, cycloalkenyl groups such as cyclohexenyl group, araryl groups such as tolyl group, xylyl group and carbon atoms of these groups Examples thereof include a chloromethyl group, a trifluoropropyl group, a cyanoethyl group in which a part or all of hydrogen atoms are substituted with a halogen atom, a cyano group, and the like, and further an amino group, an epoxy group, a mercapto group, and the like.

Further, in the chain organosiloxane of the formula (II), it is preferable that at least one group of the terminal blocking group is a group selected from a hydrogen atom, a methyl group, a vinyl group, an amino group, an epoxy group and a mercapto group. .

Further, m is preferably an integer of 0 to 20 from the viewpoint of ease of emulsification and reactivity.

Next, the surfactant for emulsion polymerization used in the present invention acts as a catalyst for polymerizing or copolymerizing the cyclic organosiloxane or the chain organosiloxane, and at the same time as a surfactant necessary for emulsion polymerization. Play a role.

In this case, as the surfactant for emulsion polymerization, various surfactants can be used, but among the anionic surfactants, a sulfonic acid surfactant and a sulfate surfactant are preferable, and particularly the following formula (III), (IV) R ⁷ C ₆ H ₄ SO ₃ H ... (III) R ⁷ OSO ₂ H ... (IV)
Aliphatic hydrogen sulfates are preferably used.

In the above formulas (III) and (IV), the substituent R ⁷ is an aliphatic monovalent hydrocarbon group having 6 or more carbon atoms, preferably 6 to 18 carbon atoms, such as hexyl group, octyl group, decyl group,
Examples thereof include dodecyl group, cetyl group, stearylmylycyl group, oleyl group, nonenyl group, octyl group, phytyl group and pentadecadienyl group.

When the sulfonic acid-based or sulfate-based surfactants of the above formulas (III) and (IV) are used as surfactants for emulsion polymerization, they are used for the purpose of stabilizing the emulsion. It is desirable to add salts of the above, salts of sulfate-based surfactants such as sodium salts, and the like.

Further, as the cationic surfactant, the following general formula (V) (However, in the formula, R ⁸ is an aliphatic monovalent hydrocarbon group having 6 or more carbon atoms, R ^{9 to} R ¹¹ are monovalent organic groups, particularly a monovalent hydrocarbon group having 1 to 20 carbon atoms. , X is a hydroxyl group, a chlorine atom or a bromine atom.) A quaternary ammonium salt surfactant is preferably used.

Here, the substituent R ⁸ is an aliphatic monovalent hydrocarbon group having 6 or more carbon atoms, preferably 8 to 18, and specifically, a hexyl group, an octyl group, a decyl group, a dodecyl group, a cetyl group, Examples thereof include stearyl group, myricyl group, oleyl group, hexadecyl group, nonenyl group, octynyl group, phytyl group, pentadecadienyl group and the like. In addition, R ^{9 to} R
¹¹ is the same or different organic group, such as a methyl group,
Examples thereof include alkyl groups such as ethyl group and propyl group, alkenyl groups such as vinyl group and allyl group, aryl groups such as phenyl group, xenyl group, naphthyl group, and cycloalkyl groups such as cyclohexyl group.

In the present invention, among the quaternary ammonium salt-based surfactants of the above formula (V), tetraalkylammonium in which at least one alkyl group among the substituents is a hydrocarbon group having 6 to 18 carbon atoms. Halide is preferably used.

Further, in the present invention, it is preferable to add a polymerization catalyst together with the surfactant for emulsion polymerization, if necessary, when the surfactant for emulsion polymerization has a low catalytic action.

Here, the polymerization catalyst is preferably selected appropriately according to the ionicity of the surfactant for emulsion polymerization to be used, and specifically, as the polymerization catalyst, sulfuric acid, hydrochloric acid, which is generally used for the polymerization of cyclic organosiloxane, Acid catalysts such as mineral acids such as phosphoric acid, alkali metal hydroxides such as sodium hydroxide and potassium hydroxide, sulfonic acid hydroxides, quaternary ammonium hydroxides, etc. An activator is exemplified.

In particular, when a quaternary ammonium salt-based surfactant is used as a surfactant for emulsion polymerization, its catalytic activity is low depending on the type, so alkali metal such as sodium hydroxide or potassium hydroxide is previously or during emulsion polymerization. It is desirable to add a polymerization catalyst such as the above-mentioned hydroxide or quaternary ammonium hydroxide.

Thus, the method for producing an organopolysiloxane emulsion of the present invention comprises the steps of preparing an emulsion A in which a cyclic organosiloxane is emulsified and dispersed in an aqueous solution containing a surfactant for emulsion polymerization, and an aqueous solution containing a surfactant for emulsion polymerization. An emulsion B in which a chain organosiloxane having a terminal blocking group is emulsified and dispersed is prepared, and the emulsion A and the emulsion B are mixed and then emulsion polymerized.

Here, when the emulsions A and B are prepared, the amount of the surfactant for emulsion polymerization to be used is not particularly limited as long as it is an amount sufficient to emulsify the cyclic or chain organosiloxane. It is preferable to use each in an amount of 0.5 to 20 parts, especially 1 to 15 parts, relative to 100 parts of the organosiloxane (parts by weight, the same applies hereinafter).

When the polymerization catalyst is added together with the surfactant for emulsion polymerization, it is preferably added in an amount of 0.1 to 5 parts, particularly 0.5 to 3 parts, relative to 100 parts of the cyclic or chain organosiloxane. .

Further, the amount of water required for emulsifying the organosiloxane is not particularly limited, but is usually 100 to 500 parts, particularly 150 to 100 parts with respect to 100 parts of the cyclic or chain organosiloxane.
It is 400 copies.

In the present invention, the above emulsions A and B are added, for example, to an aqueous solution containing a surfactant for emulsion polymerization and, if necessary, a polymerization catalyst, a cyclic or chain organosiloxane with stirring, and the mixture is added with a homomixer or homogenizer. ，
It can be obtained by passing it through an emulsifying machine such as a line mixer, colloid mill or sand grinder under appropriate emulsifying conditions to form an emulsion. Emulsion B is
A part of the cyclic organosiloxane may be added together with the chain organosiloxane for emulsification.

The emulsion thus obtained is usually 0.1 to
The average particle size is 3 μm, but from the viewpoint of emulsion stability, the average particle size is preferably 1 μm or less.

In the present invention, Emulsion A prepared by the above method
Is a cyclic organosiloxane ring-opened by a surfactant for emulsion polymerization or a polymerization catalyst, which is partially polycondensed and blocked with a terminal hydroxyl group.
40) is an intermediate latex that has been emulsified in the state of 40).
An organopolysiloxane emulsion having a predetermined viscosity and molecular weight can be obtained.

Here, by arbitrarily changing the mixing ratio of the emulsion A and the emulsion B, an organopolysiloxane emulsion having a specific viscosity having a molecular weight corresponding to the mixing ratio can be obtained. Therefore, the emulsion A and the emulsion B are obtained. The mixing ratio with the can be appropriately adjusted depending on the viscosity and molecular weight of the desired organopolysiloxane.
Is preferably mixed at a ratio of 0.05 to 100 parts, particularly 0.5 to 50 parts.

Further, it is preferable that after the emulsion A and the emulsion B are mixed, they are heated to 50 to 80 ° C. and mixed for 1 to 20 hours to carry out emulsion polymerization.

During the emulsion polymerization of the emulsion, it is possible to promote the polymerization reaction by adding 0.1 to 5 parts of a polymerization catalyst to 100 parts of the mixed solution of the emulsions A and B, if necessary.

Moreover, after emulsion polymerization, after cooling to 10-40 degreeC,
Neutralize with an alkali such as sodium carbonate when using a sulfonic acid type surfactant as a surfactant for emulsion polymerization, and with an acid such as acetic acid when using a quaternary ammonium salt type surfactant. Is desirable.

EFFECTS OF THE INVENTION As described above, according to the production method of the present invention, organopolysiloxane emulsions having various viscosities can be produced simply by changing the mixing ratio of the emulsions A and B, and are therefore excellent in manufacturability. .

Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited to the following examples.

Example 1 A mixture of 420 g of octamethylcyclotetrasiloxane, 100 g of a 10% aqueous solution of sodium lauryl sulfate, 100 g of a 10% aqueous solution of dodecylbenzenesulfonic acid and 380 g of diluting water was passed through a homogenizer at a pressure of 316 kg / cm ² , Homogenization gave Emulsion A-1.

Also, the following formula A homogenizer of a mixture of 420 g of dimethylpolysiloxane whose end is blocked with a trimethylsilyl group, 100 g of a 10% aqueous solution of sodium lauryl sulfate, 100 g of a 10% aqueous solution of dodecylbenzenesulfonic acid, and 380 g of diluting water at a pressure of 316 kg / cm ^2. It was passed through it and homogenized to obtain an emulsion B-1.

Next, these emulsions A-1 and B-1 were mixed in the proportions shown in Table 1, emulsion-polymerized at 50 ° C. for 20 hours, and then a 10% aqueous solution of Na ₂ CO ₃ was added to obtain pH 7. To neutralize to obtain Emulsions 1 to 4.

All of the obtained emulsions 1 to 4 were stable even when stored at room temperature for 6 months.

Also, collect 2g of these emulsions in an aluminum dish and
It dried at 05 degreeC for 3 hours, and measured the non-volatile matter.

In addition, 100 g of each of these emulsions was mixed with 3
After adding 00 g to break the emulsion, the supernatant was removed by decantation, washed with acetone and water, and dried in a drier at 105 ° C. for 16 hours to take out the base silicone oil. The viscosity of the obtained silicone oil at 25 ° C. was measured with an Ostwald viscometer.

The above results are shown in Table 1.

From the results in Table 1, the non-volatile content of the produced emulsion is as described above, and when the ratio of the produced polymer is calculated from the first monomer siloxane and the polymerization reaction rate is measured, it is about 88%.
It was found that the polymerization reaction was sufficiently advanced.
Further, it was found that the viscosity of the produced silicone oil can be controlled by adjusting the ratio of the emulsion B-1 having a terminal blocking group.

The method of calculating the polymerization reaction rate is as follows.

[Calculation method of polymerization reaction rate]

NV: Nonvolatile content (%) of emulsions 1 to 4 A, B: Mixing ratio of emulsions A-1 and B-1 a, b: Nonvolatile content (%) of emulsions A-1 and B-1 [Example 2] ] 420 g of octamethylcyclotetrasiloxane, 50% aqueous solution of lauryl trimethyl ammonium chloride 4
A mixture of 0 g and 540 g of dilution water was passed through a homogenizer at a pressure of 316 kg / cm ² and homogenized to obtain an emulsion A-2.

In addition, a mixture of 420 g of dimethylpolysiloxane whose ends were blocked with trimethylsilyl, 40 g of a 50% aqueous solution of lauryltrimethylammonium chloride, and 540 g of dilution water was passed through a homogenizer at a pressure of 316 kg / cm ² to homogenize the same as in Example 1. Emulsion B-2 was obtained.

Next, these emulsions A-2 and B-2 were mixed at a ratio shown in Table 2, potassium hydroxide was added as a polymerization catalyst in a predetermined amount, emulsion polymerization was carried out at 50 ° C. for 20 hours, and then acetic acid was added. Neutralize until pH 7 and emulsion 5
Got 8.

All of the obtained emulsions 5 to 8 were stable even when stored at room temperature for 6 months.

The nonvolatile content of these emulsions and the viscosity of the base silicone oil were measured in the same manner as in Example 1. The results are shown in Table 2.

From the results shown in Table 2, it was found that the polymerization reaction rate was about 88%, and the polymerization reaction proceeded sufficiently. Further, it was found that the viscosity of the produced silicone oil can be controlled by the ratio of the emulsion B-2 having a terminal blocking group.

[Example 3] A mixture of 42 kg of octamethylcyclotetrasiloxane, 10 kg of a 10% aqueous solution of sodium lauryl sulfate, 3 kg of a 10% aqueous solution of lauryl sulfate and 20 kg of diluting water was continuously rotated at a speed of 0.75 kg / min for 1900 rpm.
When it was supplied to a sand grinder of rpm at a supply pressure of 0.5 G for a residence time of 2.4 minutes, a milky paste-like emulsion was obtained. Subsequently, 250 kg of dilution water was continuously added to this emulsion at a rate of 0.25 kg / min and mixed with a line mixer to obtain 1.0 kg / min.
Emulsion A-3 was continuously obtained at a rate of minutes.

Further, 420 g of hexamethyldisiloxane, 100 g of a 10% aqueous solution of sodium lauryl sulfate, 30 g of a 10% aqueous solution of lauryl sulfate and 450 g of dilution water.
This mixture was passed through a homogenizer having a pressure of 316 kg / cm ² and homogenized to obtain an emulsion B-3.

Next, 100 g of emulsion A-3 continuously obtained
However, this emulsion A-3 and emulsion B-3 were mixed at the ratio shown in Table 3 at 50 ° C.
Emulsion polymerization was carried out for 20 hours, and a 10% aqueous solution of Na ₂ CO ₃ was added to the resulting emulsion to neutralize it until pH 7 was obtained to obtain emulsions 9 to 13.

The obtained emulsions 9 to 13 were stable even when stored at room temperature for 6 months.

The nonvolatile content of these emulsions and the viscosity of the base silicone oil were measured in the same manner as in Example 1. The results are shown in Table 3.

Claims (1)

[Claims] 1. A compound represented by the following general formula (I) in an aqueous solution containing a surfactant for emulsion polymerization. (Wherein R ¹ and R ² are each a hydrogen atom or the same or different substituted or unsubstituted monovalent hydrocarbon group, and n is an integer of 3 to 6). In the aqueous solution containing the emulsion A emulsion-dispersed and the surfactant for emulsion polymerization, the following general formula (II) (However, in the formula, R ³ , R ⁴ , R ⁵ , and R ⁶ are each a hydrogen atom or the same or different substituted or unsubstituted monovalent hydrocarbon group, and m is an integer of 0 to 20). An organopolysiloxane emulsion characterized by separately preparing an emulsion B in which a chain-like organosiloxane having a terminal blocking group as shown is dispersed, and then emulsion-polymerizing the emulsion A and the emulsion B by mixing them. Manufacturing method.