JPH0268137A - Manufacture of oil-in-water type emulsion - Google Patents

Abstract

PURPOSE:To obtain an oil-in-water type emulsion with excellently stable viscosity by forming a liquid crystal phase from an oil phase containing a cationic surfactant of a specific quaternary ammonium salt-type and a part of an aqueous phase and then adding the rest of the aqueous phase so as to transform the phase. CONSTITUTION:A part of an aqueous phase such as ethylene glycol is added to an oil phase containing a sparingly water-soluble quaternary ammonium salt-type cationic surfactant such as dioleyldimethylammonium chloride having two or three alkyl or alkenyl of 14-24 carbons in one molecule. At this time, a liquid crystal phase to give the concentration of the cationic surfactant in 20-60wt.% is formed. Then, the rest of the aqueous phase is added to the liquid crystal phase so as to transform the phase and to obtain an oil-in-water type emulsion. As a result, even in the case of high concentration, the emulsion is prevented from gelling and has excellently stable viscosity even after storage for a long period.

Description

Detailed Description of the Invention The present invention is an oil-in-water emulsion containing a quaternary ammonium salt type cationic surfactant as a dispersant, which is used as a fabric softener for clothing, a hair rinse, etc. Relating to a manufacturing method.

Obedience! Conventionally, a method for producing an oil-in-water (○/W) emulsion containing a quaternary ammonium salt type cationic surfactant as a dispersoid involves adding an oil phase containing a cationic surfactant to an aqueous phase. is known (Japanese Unexamined Patent Publication No. 57-5797). However, with this method, when the cationic surfactant concentration reaches a high concentration of about 5% by weight or more, the viscosity of the product increases and gels, or the viscosity increases during storage, resulting in problems such as not being able to be discharged from the bottle or poor dispersibility in water. There were problems such as worsening of

On the other hand, in recent years, there has been a demand for products containing cationic surfactants that are of a concentrated type with increased content of cationic surfactants.

In addition, as a method for producing an oil-in-water emulsion using a liquid crystal phase, first of all, Japanese Patent Publication No. 12653/1983 describes
(a) An oil phase component is added to a surfactant continuous phase in which a specific nonionic surfactant is dissolved in an aqueous phase component; or (b) a nonionic surfactant is dissolved in an oil phase component. An aqueous phase component is added to the oil phase continuous phase to generate a liquid crystal phase of nonionic surfactant, then an aqueous phase component is added to this liquid crystal phase to obtain a gel emulsion, and finally, water is added to this gel emulsion. It has been reported that an oil-in-water emulsion can be obtained by adding 1-dispersoid, the oil, from the liquid crystal. However, the method of the present invention utilizes the liquid crystal of a cationic surfactant rather than a nonionic surfactant, and moreover, the cationic surfactant itself becomes a dispersoid to produce an oil-in-water emuldimine. This invention is essentially different from the above-mentioned known invention.

Furthermore, JP-A-53-134784 describes a method for producing double membrane hollow vesicles by applying mechanical vibration (ultrasonic irradiation) to an aqueous solution of a lamellar phase dispersion of a quaternary ammonium salt. There is.

The present invention aims to provide an oil-in-water emulsion that does not increase in viscosity and gel even if it contains a cationic surfactant at a high concentration, and can maintain a fluid and low-viscosity state for a long period of time. The purpose of the present invention is to provide a method for manufacturing easily and economically.

The method for producing the oil-in-water emulsion of the present invention is based on the method for producing the oil-in-water emulsion of the present invention
4 to 24 alkyl or alkenyl groups in the molecule
A part of the aqueous phase is added to an oil phase containing one to three poorly water-soluble quaternary ammonium salt type cationic surfactants, or the oil phase is added to a part of the aqueous phase to form a cation interface. The method is characterized in that a liquid crystal phase of the activator is formed, and then the liquid crystal phase and the remaining aqueous phase are mixed to invert the liquid crystal phase to form an oil-in-water emulsion.

The present invention will be explained in more detail below.

In the present invention, a liquid crystal phase of the quaternary ammonium salt type cationic surfactant is first formed by adding a portion of the aqueous phase to the oil phase, or by adding the oil phase to a portion of the aqueous phase.

The oil phase may have a cationic surfactant as its main component, and this may be the only surfactant component in the oil phase. Moreover, a nonionic surfactant, a mono- to trihydric alcohol, a fragrance, etc. can be included as necessary.

The cationic surfactant forms a liquid crystal phase in the first stage and becomes a dispersoid in the final emulsion.

Specific examples of cationic surfactants include the following, which are represented by the general formula (Natsu) or (n). These can be used alone or as a mixture of two or more. These are poorly water-soluble quaternary ammonium salt type surfactants having 2 to 3 alkyl groups or alkenyl groups having 14 to 24 carbon atoms in the molecule, and these alkyl groups or alkenyl groups may be unsubstituted.

A linear or branched alkyl group or alkenyl group having 14 to 24 carbon atoms substituted or interrupted by R
The remaining group of R4 is an alkyl group having 1 to 3 carbon atoms, a hydroxyalkyl group, a group represented by 10, H40) (Q is an integer of 1 to 5), or a halogen or R, SO
, (Rs represents an alkyl group having 1 to 3 carbon atoms). ] may be substituted or interrupted by a functional group such as.

[In the formula, R represents a carbon number of 1 to 4. Preferably 1 to 2 alkyl groups, R7 and R1 are unsubstituted, substituted or interrupted straight or branched alkyl or alkenyl groups having 14 to 24 carbon atoms, and R9 is hydrogen or an alkyl group having 1 to 4 carbon atoms. , or 2N) has the same meaning. ] At least two groups among R1 to R4 in the general formula (1) have 14 to 24 carbon atoms, preferably 16 to 22 carbon atoms.
, and R in the general formula (■), R,
have 14 to 24 carbon atoms, preferably 15 to 21 carbon atoms, and each may have a distribution within these ranges, and may be the same or different from each other. As a specific example.

Dihardened tallow alkyldimethylammonium chloride, dihardened tallow alkyldimethylammonium bromide, dioleyldimethylammonium chloride, civalmitylmethylhydroxyethylammonium methyl sulfate.

Distearylmethylpolyoxyethylene (average degree of polymerization 3
mol) ammonium chloride, diisostearyldimethylammonium methyl sulfate, dieicosyldimethylammonium chloride, dibehenylmethylpolyoxyethylene (average degree of polymerization 5 mol) ammonium chloride, gelcyldimethylammonium chloride, di[(2-dodecanoylamino) )
Ethyl dimethyl ammonium chloride.

Di[(2-stearoylamino)propyl]dimethylammonium ethyl sulfate, di(2-ethylbalmitoyl)hydroxyethylmethylammonium methylsulfate, trioleylmethylammonium chloride, dioleylmonostearylmethylammonium chloride, dioleylmonobhenylmethyl Ammonium chloride, monooleylgelcylmethylammonium chloride, tristearylmethylammonium methyl sulfate methyl-1-tallowamidoethyl-2-tallow alkylimidazolinium methylsulfate, methyl-1-hexadecanoylamidoethyl-2-pentadecylimidazoli Examples include one type or a mixture of two or more of ethyl chloride, ethyl-1-octadecenoylamidoethyl-2-hebutadecenylimidazolinium ethyl sulfate, and the like.

Examples of nonionic surfactants include polyoxyethylene alkyl phenyl ether, polyoxyethylene alkyl (
or alkenyl) ethers, polyoxyethylene fatty acid amides, polyoxyethylene alkyl (or alkenyl) amines.

Examples include polyoxyethylene sorbitan fatty acid ester. Among these, POE (p=20~100
) alkyl (CI->□) phenyl ether, P OE
(p5=20-100) alkyl or alkenyl (
C1o-ax) ether, POE (β=20-100)
Alkyl or alkenyl (Ct., 2) amines or mixtures thereof are preferred. In addition, among the above compounds,
POE represents polyoxyethylene, β represents the average number of added moles of ethylene oxide, and C represents the number of carbon atoms in the alkyl group or alkenyl group.

Mono- to trihydric alcohols include ethanol, isopropanol, ethylene glycol, diethylene glycol,
Examples include triethylene glycol, propylene glycol, dipropylene glycol, 1,3-butylene gellicol, and glycerin.

On the other hand, the aqueous phase contains water, nonionic surfactants, mono- to trihydric alcohols, inorganic salts, fragrances, pigments, etc., and in some cases, viscosity modifiers such as water-soluble organic polymers, pH adjusters, and bactericides. , antioxidants, ultraviolet absorbers, and the like can be appropriately blended.

Here, as specific nonionic surfactants and mono- to trihydric alcohols, the same ones as in the case of the oil phase component can be exemplified.

Examples of inorganic salts include sodium chloride, potassium chloride, magnesium chloride, aluminum chloride, sodium sulfate, ammonium sulfate, sodium nitrate, magnesium nitrate, and the like. In addition, as water-soluble polymers,
polyacrylic acid, polymethacrylic acid, polycrotonic acid,
Examples include polycrotonic acid.

In the production method of the present invention, as a first step, the carbon number is 14 to
A part of the aqueous phase is added to an oil phase containing a poorly water-soluble quaternary ammonium salt type cationic surfactant having 2 to 3 24 alkyl or alkenyl groups in the molecule, or
Alternatively, the oil phase is added to a part of the water tank to form a liquid crystal phase. In this case, in order to form a stable liquid crystal phase, the water-insoluble quaternary ammonium salt type cation in the liquid crystal phase must be It is desirable that the concentration of the surfactant be 20 to 60% by weight, preferably 25 to 50% by weight. If the concentration is too low, a stable liquid crystal phase will not be formed, and the final O/W emulsion will become a gel. On the other hand, if the concentration is too high, the resulting emulsion will not have good viscosity stability over time and will tend to increase in viscosity over time.

The conditions for forming a liquid crystal phase are appropriately selected, but the temperature of the oil phase and aqueous phase containing the cationic surfactant may be at least the temperature at which liquid crystal is formed.
A liquid crystal phase can be easily formed under stirring at a temperature of about 50°C.

Next, in the production method of the present invention, the remaining aqueous phase is added to the liquid crystal phase obtained in the first step for phase inversion to obtain an oil-in-water emulsion.

There are no restrictions on the method or conditions for adding the aqueous phase.1 Usually, by adding the aqueous phase instantaneously or gradually while stirring, it is possible to add the aqueous phase without the need for special high-energy mechanical shearing force. An oil-in-water emulsion containing a cationic surfactant as a dispersoid can be easily obtained.

Note that, as described above, the nonionic surfactant can be added to the oil phase or the aqueous phase, but there is no problem if it is added after phase inversion. It is thought that the nonionic surfactant is uniformly oriented on the particle surface of the poorly water-soluble cationic surfactant, which is a dispersoid, and stably protects the particle.

The mechanism of action by which an oil-in-water emulsion in which gelation is prevented and whose viscosity is stable even after long-term storage is obtained by the production method of the present invention is presumed to be as follows. That is, in the present invention, a homogeneous liquid crystal phase of the cationic surfactant itself, which is a dispersoid, is formed, and this phase is inverted to form an oil-in-water emulsion. This is thought to be because the properties are higher than in the normal method and the interaction between particles is small.

According to the present invention, a liquid crystal phase is formed from an oil phase containing a specific poorly water-soluble quaternary ammonium salt type cationic surfactant and a part of the aqueous phase, and then the remaining aqueous phase is added. By creating an oil-in-water emulsion with a cationic surfactant as a dispersoid, gelation is prevented even when the concentration is increased, and the oil-in-water emulsion has excellent viscosity stability during long-term storage. easily with low-energy mechanical shear forces,
and can be produced economically.

This emulsion manufacturing method can be used in the fields of fabric softeners, hair rinses, cosmetics, and the like.

EXAMPLES Hereinafter, the effects of the present invention will be explained in more detail with reference to Examples, but first, the evaluation method of viscosity stability adopted in the Examples will be explained.

[Method for evaluating viscosity stability] The viscosity of each composition prepared in Examples and Comparative Examples was measured immediately after production and after storage under three types of conditions as described below. This measurement is performed using a B-type viscometer (manufactured by Tokyo Keiki).
The test was carried out at a temperature of 25°C.

■ Immediately after production ■ After storage at room temperature for 1 year ■ After storage at 45℃ for 1 month ■ After storage at -15℃ for 40 hours and freezing, then at 25℃
Examples 1 to 5 After preparing the oil phase and the aqueous phase as shown in Table 1, as a first step, one part of the aqueous phase at 30°C was added to the oil phase at 45°C with stirring. of di-hardened tallow alkyldimethylammonium chloride to form a liquid crystal phase at 42°C such that the concentration of di-hardened beef tallow alkyldimethylammonium chloride is 30%, and then add the remaining aqueous phase at 30°C to the liquid crystal phase to invert the phase. An oil-in-water emulsion at about 35° C. was obtained.

Note that the compositions of the oil phase and the water phase are expressed in weight percent when the final oil-in-water emulsion is taken as 100.

The evaluation results of the viscosity stability of the obtained oil-in-water emulsion are shown in Table 1 below along with other Examples and Comparative Examples described later. From Table 1, it can be seen that the products of the present invention of Examples 1 to 5 all have low viscosity immediately after production and also exhibit good viscosity stability.

Example 6 The same composition as in Example 3, but with the addition method in the first step reversed, a 45°C oil phase was added to a portion of the 30°C aqueous phase with stirring to form a 42°C liquid crystal phase. is formed, and then the remaining 30°C aqueous phase is added to the liquid crystal phase, and the phase is inverted to form a liquid crystal phase of about 3
An oil-in-water emulsion at 5°C was obtained. As a result, Table 1
As shown in , the viscosity stability was extremely good as in Example 3. Comparative Example 1 The same composition as in Example 3 was added to the aqueous phase at 30°C under stirring at 45°C according to the usual emulsification method. The oil phase was added to obtain an oil-in-water emulsion at about 35°C. As shown in Table 1, the viscosity stability of this product was extremely high immediately after production, and the stability under various storage conditions was poor, with severe thickening observed.

Comparative Examples 2 to 4 In the same composition as Example 3, in Comparative Example 2, the concentration of dicured tallow alkyldimethylammonium chloride during liquid crystal phase formation was 15%, and in Comparative Example 3, the concentration was 65%.
Further, in Comparative Example 4, the temperature during liquid crystal phase formation was 20°C.

As shown in Table 1, the viscosity stability of each product was clearly poorer than that of the product of the present invention, and a tendency to increase in viscosity was observed in each product.

Examples 7 to 9 Examples 7 to 9 are examples in which the type of cationic surfactant was changed, and as shown in Table 2 below, the viscosity stability results for each were extremely stable.

Comparative Examples 5 to 7 Comparative Examples 5 to 7 were prepared in the same manner as in Comparative Example 1 using the compositions corresponding to Examples 7 to 9 according to the usual emulsification method. The results of its viscosity stability are shown below.
Shown in 2. As is clear from Table 2, all of them had high viscosity immediately after production, had poor viscosity stability under each storage condition, and showed a tendency to increase in viscosity.

(Margin below)

Claims (1)

[Claims] 1. Adding a portion of the aqueous phase to the oil phase containing a poorly water-soluble quaternary ammonium salt type cationic surfactant having 2 to 3 alkyl groups or alkenyl groups having 14 to 24 carbon atoms in the molecule. Alternatively, the oil phase is added to a part of the aqueous phase to form a liquid crystal phase of the cationic surfactant, and then the liquid crystal phase and the remaining aqueous phase are mixed to invert the liquid crystal phase. A method for producing an oil-in-water emulsion.