JPH02969B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an emulsifying and dispersing agent of a lipophilic water-insoluble substance made of a specific modified polyvinyl alcohol (hereinafter polyvinyl alcohol will be abbreviated as PVA) having a hydrophobic group and a hydrophilic group. In the production of cosmetics, agrochemical synthetic resins, adhesives, various binders, paints, cutting oils, etc., lipophilic water-insoluble substances are often emulsified and dispersed in an aqueous medium. In this case, low-molecular surfactants are generally used as emulsifying and dispersing agents. Although it is possible to obtain a somewhat stable emulsion by appropriately selecting a low-molecular surfactant, the stability at low temperatures or when subjected to mechanical shearing force is often inferior. Practical problems may occur, such as the generation of coarse particles or large fluctuations in viscosity during thickening and gelling during winter storage, transport by pump, or application by spreader rolls. Furthermore, although using a large amount of a low-molecular-weight surfactant may solve the above stability problems, the emulsion may have a strange odor or a large amount of the surfactant may be present in the resulting film. This poses a very serious problem in practical terms, such as the adhesive performance and water resistance of the film being significantly reduced. Furthermore, there are various problems such as the fact that only low viscosity emulsions can be obtained when low-molecular active agents are used, and the development of emulsifying and dispersing agents based on polymeric surfactants is awaited. PVA is a water-soluble polymeric substance and is used in various industrial applications because of its ability to form tough films. However, because it has only simple substituents of hydroxyl and acetate groups on the carbon skeleton of its main chain, it does not have sufficient surfactant ability, and there are many difficulties when using it as an emulsifying and dispersing agent. It goes along with this. In view of this situation, the inventors of the present invention have conducted intensive research and found that by using a specific modified PVA having a hydrophobic group and a hydrophilic group as described below, lipophilic water-insoluble substances can be contained in an aqueous medium. It was discovered that the resulting emulsified dispersion is highly stable and has excellent storage properties, mechanical properties, etc., and also has excellent practical physical properties such as adhesive performance, leading to the present invention. It is ivy. That is, the present invention comprises (A) a vinyl ester of a fatty acid having 5 or more carbon atoms, (B) a monomer represented by the general formula (), In the above formula, R ₁ ; hydrogen or lower alkyl group R ₂ ; alkyl groups R ₃ , R ₄ , R ₅ ; hydrogen or alkyl group M; hydrogen or one equivalent of a cation (C) vinyl acetate; This is an emulsifying and dispersing agent that can emulsify and disperse a lipophilic water-insoluble substance in an aqueous medium made of modified PVA obtained by saponifying a copolymer contained as a copolymer component. In the modified PVA constituting the emulsifying dispersant of the present invention,
Examples of vinyl esters of fatty acids having 5 or more carbon atoms used as component (A) include vinyl valerate, vinyl caprylate, and vinyl stearate, including vinyl pivalate, 1,1,3 , 3-tetramethylbutyric acid vinyl ester or the average number of carbon atoms
More preferred are fatty acid vinyl esters having a branched alkyl group, such as saturated branched fatty acid vinyl esters. It is difficult to obtain emulsions with good stability using modified PVA using vinyl esters of fatty acids having 4 or less carbon atoms. As mentioned above, a monomer having a branched alkyl group is more preferable as component (A) because it is more stable and can provide an emulsion with good practical properties such as water resistance and adhesion. used. The reasons for this are not clear, but the ratio of methyl, methylene, and methine groups in the alkyl group is different between branched and straight-chain alkyl groups, crystal orientation,
This is thought to be due to differences in associativity, etc. Furthermore, the monomer used as component (B) is represented by the following general formula (). Here, R ₁ is hydrogen or a lower alkyl group, usually hydrogen or a methyl group, and more preferably hydrogen, R ₂ is required to be an alkyl group, and R ₃ , R ₄ , R ₅ are hydrogen Alternatively, R 3 is an alkyl group, but it is preferable that R ₃ be an alkyl group because the stability of the emulsion is greater. The reason is not clear, but it is due to the hydrophilic part within the molecule.

[Formula] The mutual steric positional relationship between the group and the -SO ₃ M group, the methylene skeleton of the main chain, the (A) component used as the hydrophobic side chain, etc.
This may be because R ₁ , R ₂ , R ₃ , R ₄ , R ₅ varies depending on the size of the groups, or in the process of copolymerizing and saponifying the monomers of formula () above, R ₁ , R ₂ , _R3 , _R4 , _R5
It is thought that the molecular structure of modified PVA changes depending on the size of the group and influences its surfactant ability. M is one equivalent of hydrogen or cation. The modified PVA constituting the emulsifying dispersant of the present invention can be obtained by saponifying a copolymer containing the above-mentioned components (A), (B), and (C) as essential components. Although the copolymerization ratio of component (A) contained in the copolymer varies depending on the number of carbon atoms, a range of 0.2 to 5 mol% is preferable among 0.05 to 10 mol%. (B) contained in the copolymer
Although the copolymerization ratio of the components varies depending on the copolymerization ratio of component (A), a range of 0.1 to 6 mol% is preferable among 0.05 to 8 mol%. The modified PVA of the present invention is a saponified copolymer having the three components (A), (B), and (C) described above as essential components, but other copolymers may be used as long as the purpose of the present invention is not impaired. Ingredients such as methacrylamide, allylamide, N
-Vinylpyrrolidone etc. are also used as copolymerization components.
In addition to the three components (A), (B), and (C), there is no problem in using a saponified copolymer. There are no particular difficulties in producing the modified PVA of the present invention, and conventionally known polymerization methods and saponification methods can be applied. In other words, as a polymerization method, components (A), (B), and (C) are added to a polymerization system all at once, in parts, or continuously depending on their respective copolymerization reactivity ratios, and the A method of polymerization using a radical polymerization initiator such as 2,2'-azobisisobutyronitrile or benzoyl peroxide in a medium or in the presence of a lower alcohol such as methyl alcohol or ethyl alcohol can be applied. (A), (B) and
As a method for saponifying the copolymer containing component (C), many known methods used for saponifying polyvinyl acetate copolymers can be applied, but usually, in an alcohol solvent or a hydroalcoholic solvent, A suitable method is saponification using an alkali such as sodium alcoholate, caustic soda, or caustic potash. As alcohol, methyl alcohol,
Lower alcohols such as ethyl alcohol are particularly preferred. In addition, these alcohols contain 40% by weight
A solvent such as acetone, methyl acetate, ethyl acetate, benzene, etc. may be contained as long as it is below. There is no particular restriction on the degree of saponification of the modified PVA, and it may be completely saponified or partially saponified, but it is preferably 60 mol% or more. The degree of polymerization of the modified PVA of the present invention should be appropriately selected depending on its intended use, but is usually in the range of 100 to 3,000. The lipophilic water-insoluble substances to be emulsified and dispersed by the emulsifying dispersant of the present invention include, for example, lubricating oils such as spindle oil and gear oil, petroleum products such as paraffin wax, liquid paraffin, and asphalt, dioctyl sepacate, Plasticizers such as dibutylphthalate, tar products such as creosote oil and coal tar, natural chemicals such as turpentine oil, tall oil, and rosin, oils and fats such as soybean oil, and castor oil,
Aromatic hydrocarbons such as benzene, toluene, xylene, paraffins, halogenated hydrocarbons,
Ketones such as methyl n-amyl ketone and di-n-propyl ketone, ethers, isocyanates such as xylylene diisocyanate and trimethylolpropane-tolylene diisocyanate duct, higher fatty acids such as caproic acid and linoleic acid, oleyl alcohol, cetyl Examples include, but are not limited to, higher alcohols such as alcohol, polyethylene, polypropylene, polyvinyl chloride, polyester, polyvinyl acetate, ethylene-vinyl acetate ester copolymers and saponified products thereof, and various synthetic rubbers. It can be widely used for emulsifying and dispersing lipophilic water-insoluble substances. For emulsification and dispersion, conventionally known methods are employed. For example, general fluid stirrers, high-speed rotation, strong shear type stirring and dispersion machines, colloid mills, pressure nozzle emulsifiers, screw extruders, ultrasonic emulsifiers, mechanical vibration stirrers, stirrers that use electrostatic fields, etc. This can be done using the method you use. There are no restrictions on the method of adding the emulsifying dispersant, and the emulsifying dispersing agent may be mixed with water and added to the lipophilic water-insoluble substance all at once, sequentially, or even continuously. There is a method in which an emulsifying dispersant is blended with a lipophilic water-insoluble substance and then mixed with water, and a method in which all three are added at the same time. There is no particular restriction on the blending ratio of modified PVA as an emulsifying dispersant, but it is preferably blended in an amount of 1 to 30% by weight based on the lipophilic water-insoluble substance described above. Other types of additives may be used in carrying out the process of the invention, such as fatty acid soda soaps, alkyl ether sulfates, benzyltrimethylammonium chloride, ionic surfactants such as dioctyl sodium sulfosuccinate, polyoxyethylene oleyl ether, sorbitan monostearer, etc. Nonionic surfactants such as acid oxyethylene oxypropylene block polymers and glycerol monostearate, water-soluble polymers such as sodium polyacrylate, polyacrylamide, unmodified or modified PVA, cellulose derivatives, and other antifoaming agents. There is no problem in adding and using known additives such as antifungal agents, antifungal agents, antirust agents, etc., as long as the purpose of the present invention is not impaired. The emulsified dispersion of a lipophilic water-insoluble substance obtained in this way is highly stable and has great industrial significance, as it can form an excellent film in the case of emulsions of synthetic resins, etc. It greatly contributes to the development of industry. The present invention will be explained in more detail with reference to examples, but the present invention is not limited thereto. Note that parts in the examples are based on weight unless otherwise specified. Example 1, Comparative Examples 1 to 3 50 parts of stearyl alcohol, 10 parts of various modified PVA shown in Table 1, and 140 parts of water were placed in a container equipped with a stirrer, heated to 90°C, and heated at 600 rpm. Stir at high speed for 30 minutes. The contents were cooled to 25°C over 20 minutes with continued stirring, and the results observed are shown in Table 1.

[Table] As shown in Example 1, when the emulsifying dispersant of the present invention was used, a good emulsion without coarse particles was obtained.
In Comparative Example 1 in which modified PVA containing only component (A) and no component (B) as a copolymerization component was used, the aqueous layer was separated and no emulsion was obtained. In addition, in Comparative Example 2, which used modified PVA containing only component (B) and no component (A) as a copolymer component, and Comparative Example 3, which used unmodified PVA, many coarse particles were generated.
No good emulsion was obtained. Example 2, Comparative Examples 4 to 7 Using an open kneader with a capacity of 60 c.c., polyisoprene rubber (cis 1 ,4 content 98%, intrinsic viscosity at 30℃ in toluene
3.3 dl/g) was kneaded at 90°C for 15 minutes, and then a mixture of 5 g of various modified PVA shown in Table 2 and 5 g of water was added little by little and kneaded to obtain a white kneaded product. Further kneading was continued and when 5g of water was added, the mixture was removed from the kneader and 50 g of water was added.
g of water, stirred, and used for subsequent tests. In Example 2, a clean emulsion without coarse particles was obtained, and the low temperature stability was also good. In Comparative Examples 4 to 6, in which PVA containing one or both of components (A) and (B) was used as a copolymerization component, a good emulsion was not obtained due to many coarse particles. Furthermore, when 10 parts of polyoxyethylene nonyl phenyl ether was added to unmodified PVA and emulsification was carried out in the same manner, a good emulsion without coarse particles was obtained in Comparative Example 7. When it was kept at 0°C for 16 hours, the entire product turned into a gel, and even when the temperature was returned to 30°C, it remained a gel-like substance, and its stability was extremely poor. Furthermore, the obtained film easily re-emulsifies when water droplets are applied and rubbed lightly with a finger, and the film has no water resistance at all, and the modified film used in the present invention
There was no way that it would be as effective as when using PVA.

【table】

Claims (1)

[Scope of Claims] 1 (A) a vinyl ester of a fatty acid having 5 or more carbon atoms, (B) a monomer represented by the general formula (), In the above formula, R ₁ ; hydrogen or lower alkyl group R ₂ ; alkyl group R ₃ , R ₄ , R ₅ ; hydrogen or alkyl group M; hydrogen or one equivalent of a cation (C) a compound consisting of three components of vinyl acetate; An emulsifying and dispersing agent that is made of modified polyvinyl alcohol obtained by saponifying a polymer and is capable of emulsifying and dispersing a lipophilic water-insoluble substance in an aqueous medium. 2. The emulsifying and dispersing agent according to claim 1, wherein component (A) is a branched fatty acid vinyl ester. 3 (B) component is R ₁ , R ₄ , R ₅ in general formula ()
The emulsifying dispersant according to claim 1, wherein is hydrogen and R ₂ and R ₃ are methyl groups. 4 Component (A) is a branched fatty acid vinyl ester.
2. The emulsifying and dispersing agent according to claim 1, wherein component (B) is a modified polyvinyl alcohol in which R ₁ , R ₄ , and R ₅ are hydrogen and R ₂ and R ₃ are methyl groups in the general formula ().