JPH0237207B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention uses specific modified polyvinyl alcohol (hereinafter referred to simply as PVA) having a hydrophobic group and a hydrophilic group as an emulsifying and dispersing agent to emulsify a lipophilic water-insoluble substance that does not have radical polymerizability. Concerning how to disperse. In the production of cosmetics, agricultural chemicals, synthetic resin adhesives, various binder 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. However, practical problems may occur, such as thickening and gelation during winter storage, generation of coarse particles during transfer using a pump, or application using a spreader roll, and large fluctuations in viscosity. Furthermore, although using a large amount of a low-molecular-weight activator may solve the above stability problems, a large amount of the activator will be contained in the resulting film, resulting in poor adhesion performance. The water resistance of the film is greatly reduced, which is a very serious problem in practice. Furthermore, there are various problems such as the fact that only low-viscosity emulsions can be obtained when low-molecular surfactants are used, and the development of an emulsification method using high-molecular 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, perhaps because it has only simple substituents of hydroxyl and acetate groups on the carbon skeleton of its main chain, it does not have sufficient surface-active ability, and is not used in many emulsifying and dispersing methods using it as an emulsifying dispersant. This is accompanied by many difficulties. In view of these actual circumstances, the inventors first proposed (A)
At least one monomer selected from the group consisting of fatty acid vinyl esters having 6 or more carbon atoms, alkyl vinyl ethers having 6 or more carbon atoms, and α-olefins having 6 or more carbon atoms, and (B) ethylenically unsaturated. A polyvinyl alcohol copolymer obtained by saponifying a copolymer containing at least one of carboxylic acid or its lower alkyl ester or acid anhydride and (C) vinyl acetate as essential components in an alcohol solution. By using it as a protective colloid in the polymerization process of ethylenically unsaturated monomers, it has high viscosity and low structural viscosity, as well as properties such as storage stability, freeze-thaw stability, high temperature stability, and stability against additives. He discovered the fact that excellent resin emulsions could be obtained even in
A patent application has been filed as 44419 (Japanese Unexamined Patent Publication No. 135882/1982). Generally, emulsion polymerization involves polymerizing polymerizable monomers using a water-soluble radical initiator and an emulsifier. Although the mechanism of action of emulsifiers and protective colloids in emulsion polymerization is not necessarily clear, the role of emulsifiers in emulsion polymerization is first of all to provide a site for polymerization. In emulsion polymerization, the polymerizable monomer is solubilized by the solubilizing action of the emulsifier. Polymerization is initiated by the attack of the water-soluble radical initiator on the solubilized monomer. Without this solubilizing effect, water-soluble radicals would not be able to attack the monomers and smooth polymerization would not proceed. Furthermore, in the case of monomers such as vinyl acetate, when PVA-based polymers are used as emulsifiers and protective colloids, vinyl acetate and
A graft polymer is formed between the resin and the PVA polymer, which has a large effect on the stability and practical properties of the resin emulsion. On the other hand, the emulsification and dispersion method of the present invention is so-called post-emulsification, in which a lipophilic water-insoluble substance is dispersed in an aqueous medium by mechanical force, and the effect of the emulsifier is mainly to disperse it. Stabilization is achieved by lowering the interfacial energy between the phase and the aqueous phase. There, "wetting" of lipophilic water-insoluble substances
Focusing on this, the so-called HLB emulsifier is considered. Surfactants have many functions such as wetting, cleaning, emulsifying and dispersing, solubilizing, antifoaming/foaming, catalytic, and antistatic functions, and although the theoretical basis for these functions is not necessarily clear, they are effective in solubilizing. In terms of action, in the homologous series, those with larger lipophilic groups, that is, those with alkyl groups with a larger number of carbon atoms, have greater solubilizing ability, and HLB depends on the size of the hydrophobic group and the hydrophilicity. It can be said to be a balance of basic sizes. Furthermore, in emulsion polymerization, there is the influence of graft polymerization as mentioned above, and emulsion polymerization and so-called post-emulsification are technically completely different fields, and in industry, emulsion polymerization industry and post-emulsification industry are In view of the fact that the former is mainly used in industrial fields such as adhesives and paints, and the latter is mainly used in industrial fields such as cosmetics, agricultural chemicals, and oils, emulsion polymerization is the most established post-emulsification technology. It has an industrial significance different from that in technology. However, as a result of repeated research in order to apply the same type of modified polyvinyl alcohol used as a protective colloid in the emulsion polymerization method developed earlier, the present inventors have found that the following specific requirements have been met. If modified PVA that satisfies the above criteria is used, it is possible to emulsify and disperse lipophilic water-insoluble substances that do not have radical polymerizability in an aqueous medium, and the resulting emulsified dispersion has excellent stability, storage stability, mechanical properties, etc. The present inventors have discovered that it has excellent practical properties such as adhesion performance, and has developed the present invention. That is, the present invention provides (A) a vinyl ester of a fatty acid having 5 or more carbon atoms;
At least one monomer selected from the group consisting of vinyl ethers of alkyl groups having 4 or more carbon atoms and α-olefins having 6 or more carbon atoms; (B) ethylenically unsaturated carboxylic acid or its lower alkyl ester or acid; An aqueous medium using a modified polyvinyl alcohol as an emulsifying dispersant, which is a saponified product of a copolymer containing as essential copolymerization components at least one kind of anhydride and (C) vinyl acetate ester, and which satisfies the following formula (). This is an emulsification and dispersion method consisting of emulsification and dispersion of a lipophilic water-insoluble substance that does not have radical polymerizability. 0.1D50 () D=nA+(1-Δ)C/27.5/lB However, A is the copolymerization ratio of component (A) (on a molar basis), which is 0.05 mol% or more, and B is the copolymerization ratio of component (B). (on a molar basis) is 0.1 mol% or more and 4.2 mol% or less, C is the copolymerization ratio of component (C) (on a molar basis)
50 mol% or more, n is an integer of 4 or more, but when component (A) is a vinyl ester of a fatty acid, n = number of carbon atoms in the fatty acid - 1, and when component (A) is an alkyl vinyl ether, n
= number of alkyl groups, when component (A) is α-olefin, n = number of carbon atoms in α-olefin −2, l is the number of carboxyl groups in component (B), △ is the saponification ratio of component (C) (on a molar basis) and △ = saponified component (C)/component (C), respectively. In the present invention, the number of carbon atoms used as component (A) is 5.
Vinyl esters of the above fatty acids include, for example, vinyl valerate, vinyl caprylate, vinyl myristate, vinyl stearate, among others, vinyl bivalate 1,1,3,3-tetramethylbutyric acid vinyl ester, and average carbon number is 10
Fatty acid vinyl esters having a branched alkyl group, such as saturated branched fatty acid vinyl esters, are preferred. If the number of carbon atoms is 4 or less, it is difficult to obtain an emulsion with good stability. In addition, as vinyl ether of alkyl having 4 or more carbon atoms, butyl vinyl ether,
Examples include octyl vinyl ether and lauryl vinyl ether. Among them, vinyl ethers having a branched alkyl group such as isoamyl vinyl ether are preferred. If the number of carbon atoms is 3 or less, it is difficult to obtain an emulsion with good stability. Also, α with carbon number of 6 or more
-Olefins include heptene-1 and octene-
1, dodecene-1, and the like are preferred. If the number of carbon atoms is 5 or less, the stability of the emulsion is poor and it cannot be applied. As the alkyl group having 4 or more carbon atoms, a branched alkyl group is more preferably used because an emulsion with high stability can be obtained. The reason for this is not clear, but it is due to the fact that the ratio of methyl, methylene, and methine groups in the alkyl group is different between branched and straight-chain alkyl groups, and differences in crystallinity, orientation, association, etc. It is thought that they may do so. Further, as the ethylenically unsaturated carboxylic acid or its lower alkyl ester or acid anhydride used as component (B), acrylic acid, methacrylic acid,
Crotonic acid, maleic acid, itaconic acid, ethyl acrylate, methyl methacrylate, methyl crotonic acid, citraconic acid,
Citraconic acid diethyl ester, maleic acid, maleic acid monomethyl ester, maleic acid diethyl ester, itaconic acid dimethyl ester, maleic anhydride, aconitic acid, etc. are used.
Citraconic acid, maleic acid, itaconic acid, maleic acid monomethyl ester, and maleic anhydride are preferably used, but the stability of the emulsion is greater when maleic acid, maleic anhydride, maleic acid monomethyl ester, and itaconic acid are used. , is even more suitable. The reason for this is not clear, but it is thought that the polymerizability with components (C) and (A), the mutual positional relationship of the introduced carboxyl groups, etc. influence the performance of modified PVA. The modified PVA used in the present invention contains (A), (B), and (C) contained in the copolymer obtained by copolymerization with the above-mentioned three components (A), (B), and (C) as essential components. The copolymerization ratio of the three components and the saponification ratio of the acetyl group of component (C) vary depending on the target lipophilic water-insoluble substance, but are selected from within the range of formula () below. 0.1D50 ......() D=nA+(1-△)C/27.5/lB However, A: Copolymerization ratio of component (A) (molar basis), which is 0.05
Mole% or more B: Copolymerization ratio of component (B) (molar basis), which is 0.1
mol% or more, 4.2 mol% or less Number-1 (A) When component is an alkyl ether, n = number of alkyl groups (A) When component is α-olefin, n = number of carbon atoms in α-olefin – 2 l; (B) Number of carboxyl groups in component △: Saponification ratio (mole basis) of component (C) △=Saponified component (C)/component (C) When using modified PVA that exceeds the range of formula () above, lipophilic non-lipophilic The emulsification and dispersion of the water-soluble substance may not be sufficiently carried out, or even if it can be emulsified and dispersed, the stability of the obtained emulsion dispersion is poor and the object of the present invention cannot be achieved. The reason for this is that in modified PVA, the balance between hydrophobicity, which is mainly based on component (A) and unsaponified component (C), and hydrophilicity, which is mainly based on component (B), is lost, and emulsion dispersion stability can no longer be maintained. This is thought to be due to the Furthermore, in the present invention, effective emulsification and dispersion can only be carried out by using modified PVA that satisfies the above-mentioned formula (2), and when the entire modified PVA is taken as 100 on a molar basis, If the amount is less than 0.05 mol% for component () and 0.1 mol% or more than 4.2 mol% for component (B), it is no longer possible to obtain a stable emulsion. Also, component (C)
Modified PVA is no longer present if less than 50 mol%
The strong film-forming properties that PVA originally possesses are lost, and the resulting emulsion suffers from a decline in practical physical properties such as adhesive performance. The modified PVA used in the present invention is as described above (A), (B),
A saponified product of a copolymer having the three components (C) as essential components, but other copolymer components such as methacrylamide, N-substituted methacrylamide, acrylamide, N-substituted Acrylamide, N-vinylpyrrolidone, 3 carbons
Vinyl ether of the following alkyl group, carbon number is 5
The following olefins 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 obtained by copolymerization. There are no particular difficulties in producing the modified PVA used in 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 In a medium or in the presence of lower alcohols such as methyl alcohol and ethyl alcohol, 2.
A method of polymerization using a radical polymerization catalyst such as 2'-azobisisobutyronitrile or benzoyl peroxide can be applied. As a method for saponifying the copolymer containing components (A), (B), and (C) obtained in this way, many known methods used for saponifying polyvinyl acetate copolymers can be applied. However, usually in an alcoholic solvent or a hydroalcoholic solvent,
A suitable method is saponification using an alkali such as sodium alcoholate, caustic soda, or caustic potash. As the alcohol, lower alcohols such as methyl alcohol and ethyl alcohol are particularly suitable. In addition, these alcohol solvents are
Not more than 40% by weight of acetone, acetic acid methyl ester,
It may also contain a low dielectric constant solvent such as ethyl acetate or benzene. The degree of polymerization of the modified PVA used in the present invention should be appropriately selected depending on its intended use, but is usually within the range of 100 to 3,000. In the emulsification and dispersion method of the present invention, lipophilic water-insoluble substances that do not have radical polymerizability and are to be emulsified include, for example, lubricating oils such as spindle oil, machine oil, and gear oil, paraffin wax, liquid paraffin, and asphalt. petroleum products, plasticizers such as dioctyl sebacate and dibutyl phthalate, 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, and xylene, paraffins, halogenated hydrocarbons, ketones such as methyl n-amyl ketone and di-n-propyl ketone, ethers, xylene diisocyanate, and trimethylolpropane. Isocyanates such as tolylene diisocyanate adduct,
Higher fatty acids such as caproic acid and linoleic acid,
Higher alcohols such as oleyl alcohol and cetyl alcohol, polyethylene, polypropylene,
Examples include, but are not limited to, synthetic resins such as polyvinyl chloride, polyester, ethylene-vinyl acetate copolymer and saponified products thereof, polyvinyl acetate ester, and various synthetic rubbers, and do not have radical polymerizability. 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. In addition, when adding an emulsifying dispersant, there is no particular restriction on the method, and the emulsifying dispersing agent may be blended with water and then added and mixed with the lipophilic water-insoluble substance all at once, sequentially, or even continuously. There are several methods, including 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 a range of 1 to 30% by weight based on the lipophilic water-insoluble substance mentioned above, but it is of course limited to this range. isn't it. 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. rate oxyethylene oxypropylene block polymer,
Nonionic surfactants such as glycerol monostearate, water-soluble polymers such as sodium polyacrylate, polyacrylamide, unmodified or modified PVA, cellulose derivatives, and other antifoaming agents, antifungal agents, There is no problem in adding known additives such as rust preventives to the extent that they do not impair the purpose of the present invention. The emulsified dispersion of a lipophilic water-insoluble substance that does not have radical polymerizability obtained in this way is highly stable, and when used with emulsions of synthetic resins, it is possible to obtain excellent films. It has industrial significance and greatly contributes to the development of industry. EXAMPLES The present invention will be explained in more detail with reference to examples below, but the present invention is not limited thereto. Note that parts in the examples are based on weight unless otherwise specified. Examples 1 to 3, Comparative Examples 1 to 3 Modified PVA containing the various copolymer components listed in Table 1 was used to examine its emulsifying performance as follows. That is, 20 parts of modified PVA was dissolved in 500 parts of water, and then 400 parts of castor oil was gradually added at 25° C. while stirring with a homomixer to obtain an emulsion. Immediately pour the emulsion into a lidded container with a radius of 3 cm and a height of 50 cm.
The results were expressed as a percentage of the total height of the emulsified layer after being left at 25°C. The results are shown in Table-1. Example 1,
Both emulsions No. 2 and No. 3 were stable emulsions, and no separation of the emulsion layer occurred in either case even after 20 days. (B)
In Example 2, in which maleic anhydride was used as a component, the emulsified state remained even after 30 days. (A) component is 0.05
In Comparative Examples 1, 2, and 3 where the amount of component (B) is less than 0.1 mol% or both are not used, the emulsion becomes an emulsion, but the emulsion collapses in 1 to 3 days and the stability is poor. It was.

[Table] Examples 4-5, Comparative Examples 4-8 50 parts of stearyl alcohol, 10 parts of modified PVA,
Pour 140 parts of water into a container with a stirrer and heat to 85℃.
Stir for 2 hours at a speed of 600 rpm. While stirring was continued, the contents were cooled to 25° C. over 20 minutes and then taken out. The results are shown in Table-2. When using lauryl vinyl ether as component (A) and crotonic acid as component (B), D = 14.9, and (A)
When stearyl vinyl ether was used as a component and crotonic acid was used as component (B), a good emulsion was obtained at D=47.5, but when D=56.2 and D=138.3, the aqueous layer was separated and a good emulsion was obtained. I couldn't get it. Furthermore, when either component (A) or (B) was not used, a good emulsion was not obtained due to the presence of many coarse particles. Further, when ethyl vinyl ether having an alkyl group having 2 carbon atoms was used as component (A) and crotonic acid was used as component (B), there were many coarse particles and a good emulsion could not be obtained.

[Table] Examples 6 to 9, Comparative Examples 9 to 13 Containing a small amount of 3,5-di-t-butyl-4-hydroxytoluene as an antiaging agent using an open kneader with a capacity of 60 c.c. After kneading 40 g of polyisoprene rubber (98% cis-1,4-content, intrinsic viscosity 3.4 dl/g at 30°C in toluene) at 90°C for 15 minutes, a mixture of 5 g of various modified PVA and 5 g of water was added little by little. Upon kneading, a white kneaded product was obtained.
Further kneading was continued and when 5g of water was added, it was taken out from the kneader and poured into 50g of water and stirred.
It was used for later tests. Appearance: The sample was applied thinly and uniformly onto a clean glass plate using a glass rod, and immediately inspected with the naked eye for the presence of coarse particles and foreign matter. Low temperature stability: Place the sample in a polyethylene container with a lid and keep it at 0℃ for 16 hours, then put it in a constant temperature water bath.
After leaving it at 30℃ for 1 hour, stir it with a glass rod and observe the condition at that time. Film performance: Pre-weighed emulsion to a thickness of 0.5 mm was cast on a plate kept horizontally in a constant temperature and humidity room at 20°C and 60% RH.The transparency of the film obtained above was is determined by the naked eye. In Examples 6 to 9, clean emulsions without coarse particles were obtained and the low temperature stability was also good. In Comparative Example 9, D=0.07, and in Comparative Example 10, D=0.06
However, since neither of them satisfied the preferred range of the present invention, only an emulsion containing many coarse particles was obtained. When a monomer such as butyl vinyl ether or lauryl vinyl ether having a linear alkyl group is used as component (A), VeoVa-10 (vinyl ester of saturated branched fatty acid with an average carbon number of 10 manufactured by Ciel Chemical Co., Ltd.) The transparency of the film obtained from the emulsion is better when a monomer having a branched alkyl group is used. Furthermore, when a similar emulsification operation was performed using 10 parts of polyoxyethylene nonyl phenyl ether in addition to PVA that does not use both components (A) and (B), a good emulsion was obtained in Comparative Example 13. Although the obtained product was kept at 0°C for 16 hours, the entire product turned into a gel, and its stability was extremely poor. Furthermore, the film obtained was cloudy and cloudy, and could not achieve the same effect as the modified PVA used in the present invention.

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Claims (1)

[Scope of Claims] 1 (A) A monomer selected from the group consisting of vinyl esters of fatty acids having 5 or more carbon atoms, vinyl ethers of alkyl groups having 4 or more carbon atoms, and α-olefins having 6 or more carbon atoms. (B) at least one ethylenically unsaturated carboxylic acid or its lower alkyl ester or acid anhydride;
(C) A saponified product of a copolymer containing three components of vinyl acetate as essential copolymerization components, which has radical polymerizability in an aqueous medium using modified polyvinyl alcohol that satisfies the following formula () as an emulsifying dispersant. An emulsification and dispersion method consisting of emulsification and dispersion of lipophilic water-insoluble substances. 0.1D50 () D=nA+(1-Δ)C/27.5/lB However, A is the copolymerization ratio (molar basis) of component (A), which is 0.05 mol% or more, and B is the copolymerization ratio of component (B). (on a molar basis) is 0.1 mol% or more and 4.2 mol% or less, C is the copolymerization ratio of component (C) (on a molar basis)
50 mol% or more, n is an integer of 4 or more, but when component (A) is a vinyl ester of a fatty acid, n = number of carbon atoms in the fatty acid - 1, and when component (A) is an alkyl vinyl ether, n
= number of alkyl groups, when component (A) is α-olefin, n = number of carbon atoms in α-olefin −2, l is the number of carboxyl groups in component (B), △ is (C) in modified polyvinyl alcohol It is the saponification ratio of the components (on a molar basis), and △ = saponified component (C)/component (C), respectively. 2 The emulsifying dispersant contains a branched fatty acid vinyl ester in which the carboxyl group is present at the α-position relative to a tertiary or quaternary carbon atom as the component (A), and an ethylenically unsaturated dicarboxylic acid or its lower class as the component (B). The emulsifying and dispersing method according to claim 1, which is a modified polyvinyl alcohol containing an alkyl monoester or diester or an acid anhydride. 3. The emulsifying and dispersing method according to claim 2, wherein component B is maleic acid monomethyl ester or maleic anhydride. 4 Claim 2 in which component B is itaconic acid
The emulsification dispersion method described in .