JPH0548771B2 - - Google Patents

Description

[Detailed description of the invention]

FIELD OF THE INVENTION The present invention relates to a method for producing an aqueous dispersion capable of forming a film having excellent water resistance, oil resistance, chemical resistance, and adhesion to hydrophobic materials. Prior Art and Technical Problems of the Invention Aqueous dispersions of various polymers have been known. For example, a fluid aqueous dispersion (hereinafter referred to as an aqueous dispersion) with a water content of approximately 30% by weight or more is applied to the surface of paper, fibers, plastic moldings, wood, metal, etc. It is dried to form a resin film, which imparts water resistance, oil resistance, and chemical resistance to base materials, and is used as a heat sealing agent. Since such aqueous dispersions use water as a dispersion medium, they are very advantageous compared to solvent-based ones in terms of flammability, work environment problems, and ease of handling, and are used in a wide range of fields. It is used in In addition to the above-mentioned aqueous dispersions, aqueous dispersions that have no fluidity and appear to be solids (hereinafter referred to as aqueous dispersions) are also known.
In other words, it is a powder-like substance known as a powder emulsion, which is redispersed by adding water to form an aqueous dispersion, and its composition contains no water at all, or at most, It is 2 to 3% by weight, and therefore has the advantage that it does not need to freeze even at low temperatures, making packaging and transportation easy and requiring less space for storage.
Furthermore, it is possible to directly mix powders and granules that do not want to come into contact with water, such as cement, mortar, and plaster, which is difficult to do with aqueous dispersions, making it possible to manufacture highly processed formulations. are doing. However, in conventionally known methods for producing aqueous dispersions, it has not been possible to produce the above-mentioned aqueous dispersions and aqueous dispersions using the same method. That is, in order to produce an aqueous dispersion, an aqueous dispersion with a high water content is first produced by various known methods, and then this aqueous dispersion is sprayed into hot air in a furnace using a sprayer. , the water is evaporated and it is made into a powder. However, when this method uses an aqueous dispersion of a low softening temperature polymer as a raw material, the polymer particles may clump during spraying, or the resulting powder emulsion may aggregate into clumps under the action of heat or pressure. There is a tendency. This kind of powder emulsion is
Even if redispersion is performed by adding water, the dispersion may not be successful, or even if dispersion is possible, the viscosity may become high or the physical properties of the coating film may deteriorate. For this reason, various additives such as anti-caking agents and protective colloids are usually added to the aqueous dispersion before spraying or the powder before drying, but if the amount added is not large, the texture will be poor.
As a result, there is a problem that the physical properties of the paint film deteriorate.
Furthermore, since a large amount of water is evaporated, energy loss is large and it is not economical. Therefore, it is desired to develop a technique for producing an aqueous dispersion such as a powder emulsion using a method with as little additives as possible and with little energy loss. Improvements are also desired in the method for producing aqueous dispersions. That is, conventionally known manufacturing methods can be broadly divided into a method of emulsion polymerization in an aqueous medium in the presence of an emulsifier and a method of manufacturing by stirring and mixing a molten resin and an aqueous medium in the presence of shear force. The former method is limited in the types of resins that can be polymerized;
There are problems such as the complexity of controlling the polymerization reaction and the complexity of the equipment. On the other hand, the latter method has the advantage that it can be applied to any resin and is relatively simple in terms of equipment and operating technology. Many proposals have been made regarding the latter method; for example, Japanese Patent Application Laid-Open No. 12835/1983 discloses a method in which a kneaded mixture of a thermoplastic resin and a water-soluble polymer is dispersed in water. However, the film obtained using the aqueous dispersion produced by this method has problems in that it has low mechanical strength and poor water resistance because it contains a water-soluble polymer. Japanese Patent Publication No. 57-23703 discloses a method of dispersing in water a kneaded mixture of polypropylene, a surfactant, and a dispersant selected from water-soluble or water-swellable polymers. However, this method has the problem that the diameter of the dispersed particles is relatively large and that petroleum resin must be used in combination to reduce the particle diameter, resulting in a sticky film. Furthermore, JP-A No. 56-2149 discloses a method for obtaining an aqueous dispersion by kneading an olefin resin and a partially saponified polyvinyl alcohol aqueous solution, but since this method also contains a water-soluble resin, the physical properties of the film are becomes worse. Moreover, the aqueous dispersion obtained by this method has a water content of 30% by weight or more. As yet another method,
The technique disclosed in the above issue, that is, the method of melt-kneading polyolefin and carboxyl group-containing polyolefin, feeding them into hot water containing a basic substance, and applying shearing force to obtain a dispersion, is a method for obtaining water-soluble or water-swellable polyolefin Although this is a suitable method because it does not contain a polymer and does not use petroleum resin, there is a problem in that the type of raw material resin is limited in order to produce particles with small dispersed particle diameters. Furthermore, since the dispersion process is carried out at high temperature and high pressure, there is a problem in that the container used during dispersion must have pressure resistance. Therefore, among the various methods for manufacturing aqueous dispersions that have been proposed, there is a method to obtain an aqueous dispersion of fine particles that can be applied to any resin without using water-soluble or water-swellable polymers, petroleum resins, etc. development is desired. Furthermore, there is also a desire for the development of a method for freely and extremely easily producing aqueous dispersions and aqueous dispersions without involving any special steps. In an unpublished patent application, the inventors previously disclosed that (i) a thermoplastic resin; and (ii) a neutralizable and/or saponifiable carboxylic acid, its anhydride or its ester groups per gram of polymer.

[Formula] A thermoplastic polymer containing a concentration of 0.1 millimolar equivalent or more in terms of a group, and (iii) an organic compound that reacts with a basic substance to become an anionic surfactant.
a basic substance and 3 to 25% by weight of water based on the total are added to the melt-kneaded product and melt-kneaded to convert the organic compound (iii) into an anionic surfactant, and In the thermoplastic polymer (i), per gram of polymer

[Formula] It was proposed that an excellent aqueous dispersion can be obtained by a step of generating 0.1 to 5 mmol equivalents of carboxylate groups in terms of groups and inverting the phase of the resin solid content into an aqueous dispersion. Outline and Object of the Invention The present inventors have developed an anionic surfactant (iii) in addition to the thermoplastic resin (i) and the functional thermoplastic resin (ii).
When melt-kneaded in advance, by simply adding a basic substance and a limited amount of water to this kneaded composition and melt-kneading, phase inversion occurs, that is, water becomes the dispersion medium phase and the solid content becomes extremely finely dispersed. Conversion to a particulate phase results in an apparently solid aqueous dispersion, and once such phase inversion occurs, it can be supplemented with additional amounts of water, either in-system or externally. It has been found that fine particle size aqueous dispersions with a wide range of water contents can be obtained. That is, the object of the present invention is to have a resin solid that has an ultrafine particle size and is an oil-in-water dispersion, even though the water content is extremely low, and that the solid content is dissolved in the water phase by adding water. It is an object of the present invention to provide a method for producing an aqueous dispersion having the property of uniformly dispersing ultrafine particles in an aqueous dispersion. Another object of the present invention is to provide a method for producing an aqueous dispersion in which the dispersed particle size is controlled within an extremely fine range despite not containing any water-soluble or water-swellable components. Still another object of the present invention is to provide a method for producing an aqueous dispersion of a thermoplastic resin in which phase inversion occurs with a small amount of water. Still another object of the present invention is to provide a method for producing an aqueous dispersion of a thermoplastic resin without requiring large-scale equipment and with low thermal energy costs. Structure of the Invention According to the present invention, (i) a thermoplastic resin, (ii) a neutralizable and/or saponifiable carboxylic acid, its anhydride or its ester group bonded to the polymer chain is added to the polymer. a step of melt-kneading a thermoplastic polymer containing a concentration of 0.1 mmol equivalent or more in terms of -COO- group per 1 gram, and (iii) an anionic surfactant; By sequentially adding 25% by weight of water and melt-kneading, 0.1 to 5 mmol equivalent of carboxylic acid salt groups, calculated as -COO- groups, are added to the thermoplastic resin (i) per gram of the resin. and inverting the dispersion medium phase from the resin to water to obtain an aqueous dispersion, and if necessary, an additional amount of water is added to the aqueous dispersion. provided. Preferred Embodiments of the Invention The present invention will be explained in detail below. Thermoplastic resin (i), which is one of the components constituting the aqueous dispersion of the present invention, is not only water-insoluble and non-swellable, but also has poor dispersibility in water. It is a thermoplastic resin that lacks, such as low density polyethylene, high density polyethylene, polypropylene, poly 1-butene, poly 4-methyl-1-pentene or ethylene, propylene, 1-butene, 4-
Polyolefins such as random or block copolymers of alpha-olefins such as methyl-1-pentene, ethylene/vinyl acetate copolymers, ethylene/vinyl alcohol copolymers, ethylene/vinyl chloride copolymers, etc. Compound copolymers, polystyrene, acrylonitrile/styrene copolymers, ABS, styrenic resins such as α-methylstyrene/styrene copolymers, polyvinyl chloride, polyvinylidene chloride, vinyl chloride/vinylidene chloride copolymers, polyacrylics polyamides such as nylon 6, nylon 6-6, nylon 6-10, nylon 11, nylon 12, thermoplastic polyesters such as polyethylene terephthalate and polybutylene terephthalate, polycarbonate, polyphenylene Any resin such as nylene oxide or a mixture thereof may be used. Among these thermoplastic resins, olefin resins are particularly preferred, such as polyethylene, polypropylene, poly-1-butene, poly-3-methyl-1-butene, poly-4-methyl-1-pentene, poly-3- Ethylene, propylene, 1-butene, 3, represented by methyl-1-pentene, ethylene/propylene copolymer, ethylene/1-butene copolymer, propylene/1-butene copolymer
-Methyl-1-butene, 4-methyl-1-pentene, 3-methyl-1-pentene, 1-heptene,
α of 1-hexene, 1-decene, 1-dodecene, etc.
- Single or copolymers of olefins, or copolymers of α-olefins and conjugated or non-conjugated dienes, such as ethylene-butadiene copolymers and ethylene-ethylidene norbornene copolymers, or ethylene-propylene-butadiene Representative examples include ternary copolymers, ethylene/propylene/dicyclopentadiene ternary copolymers, ethylene/propylene/ethylidene norbornene ternary copolymers, ethylene/propylene/1,5-hexadiene ternary copolymers, etc. Examples include copolymers of two or more α-olefins and a conjugated diene or a non-conjugated diene. Among them, the particularly suitable one is α
- A homopolymer or a copolymer of olefins. The thermoplastic resin (i) preferably has a melt flow rate (ASTMD1238, MFR) of 1 g/10 min or more, preferably 5 g/10 min or more. MFR
If it is less than 1 g/10 min, the melt viscosity becomes too high, making it difficult to melt and knead, making it difficult to obtain a suitable aqueous dispersion. The functional thermoplastic polymer (ii), which is another component constituting the aqueous dispersion of the present invention, is the above-mentioned thermoplastic resin,
or graft copolymerization of a monomer having a neutralized or unneutralized carboxylic acid group or a monomer having a saponified or unsaponified carboxylic acid ester group to its constituent monomers. , block copolymerization, random copolymerization, etc., and in some cases, a neutralization reaction or saponification reaction is performed with a basic substance, so that the total amount of carboxylic acid salts formed in the polymer is in 1 gram of polymer

[Formula] It is adjusted to contain 0.1 to 5 mmol equivalents, particularly 0.2 to 4 mmol equivalents in terms of the group. In this case, the polymer may be a partially neutralized product or a partially saponified product in which carboxylic acid groups or carboxylic acid ester groups that are not neutralized or saponified coexist. Additionally, the thermoplastic polymer (ii) must not be water-soluble or water-swellable. If the total amount of incorporated carboxylic acid groups and/or saponified carboxylic acid ester groups is outside the above range, the thermoplastic resin (i) will not have a good dispersion function and will not work to help the dispersion of the thermoplastic resin (i). Can not do it. Moreover, if it is water-soluble or water-swellable, the physical properties of the coating film will deteriorate. When the thermoplastic polymer (ii) containing the above-mentioned carboxylate group is obtained by post-neutralization or post-saponification, the raw material polymer is, for example, the above-mentioned thermoplastic resin.
It is a copolymer of a monomer common to the monomer constituting (i), especially α-olefin, and an ethylenically unsaturated carboxylic acid or its ester, and (meth)acrylic acid is the unsaturated carboxylic acid. , maleic acid, fumaric acid, tetrahydrophthalic acid, itaconic acid, citraconic acid, crotonic acid, isocrotonic acid, nadicic acid (endocys-bicyclo[2,
2,1] hept-5-ene-2,3-dicarboxylic acid), maleic anhydride, citraconic anhydride, etc., monoesters of the above unsaturated carboxylic acids such as methyl, ethyl, and propyl as unsaturated carboxylic esters; Examples include diester. Of course, instead of copolymerizing multiple monomer components, thermoplastic resins
(i) For example, a thermoplastic polymer for post-neutralization or post-saponification can be obtained by graft polymerizing a monomer such as an ethylenically unsaturated carboxylic acid, its anhydride, or its ester to an olefinic resin. It will be obvious to those skilled in the art that Of course, the amount of monomers of these ethylenically unsaturated carboxylic acids, their anhydrides, or their esters introduced must be sufficient to provide the concentration of the carboxylic acid salt specified in the claim. Not,

The group must have a concentration of at least 0.1 mmol equivalents/g polymer, preferably in the range 0.1 to 5 mmol equivalents/g polymer. Basic substances used for neutralization and saponification include substances that act as bases in water such as alkali metals, alkaline earth metals ammonia and amines, alkali metal oxides, hydroxides, weak acid salts,
Examples include substances that act as bases in water, such as hydrides, alkaline earth metal oxides, hydroxides, weak acid salts, and hydrides, and alkoxides of these metals. Examples of such substances are shown below. (1) Examples of alkali metals include sodium and potassium; alkaline earth metals include calcium, strontium, and barium; (2) amines include inorganic amines such as hydroxylamine and hydrazine, methylamine, ethylamine, and ethanolamine. , cyclohexylamine, (3) Examples of oxides, hydroxides, and hydrides of alkali metals and alkaline earth metals include sodium oxide, sodium peroxide, potassium oxide, potassium peroxide, calcium oxide, strontium oxide, and barium oxide. , sodium hydroxide, potassium hydroxide, calcium hydroxide, strontium hydroxide, barium hydroxide, sodium hydride, potassium hydride, calcium hydride, (4) Weak acid salts of alkali metals and alkaline earth metals include carbonate. sodium, potassium carbonate,
Compounds of sodium bicarbonate, potassium bicarbonate, calcium bicarbonate, sodium acetate, potassium acetate, calcium acetate, (5) ammonia and amines include:
Examples include ammonium hydroxide, quaternary ammonium compounds such as tetramethylammonium hydroxide, hydrazine hydrate, and the like. As the carboxylic acid group or carboxylic acid ester group that has been neutralized or saponified with a basic substance, alkali metal carboxylates such as sodium carboxylate and potassium carboxylate, and ammonium carboxylate are suitable, and potassium carboxylate is especially preferred. preferable. The functional thermoplastic polymer (ii) is preferably selected to have good compatibility with the target thermoplastic resin (i). That is, when the objective is an aqueous dispersion of an olefinic resin, a polymer containing an olefinic monomer in the polymer chain should be selected. For example, when using polyethylene, polyolefin, ethylene/vinyl acetate copolymer, etc., these maleic acid grafted products or ethylene/(meth)
It is preferable to use neutralized or saponified products such as acrylic acid copolymers and ethylene/methyl (meth)acrylate copolymers. One guideline for selecting a suitable thermoplastic polymer is the solubility parameter (Sp value). That is, the difference in solubility parameters between the raw material polymer (ii) and the thermoplastic resin (i) before being neutralized or saponified is within 2 (cal/cm ³ ) ^1/2 ;
In particular, it is preferably within 1 (cal/cm ³ ) ^1/2 . Herein, the solubility parameter (Sp
"value" has the usual meaning, that is, a value defined as the value of the cohesive energy density to the 1/2 power. This solubility parameter is the contribution of the atomic group to the molar volume.
Vi and the cohesive energy En of the atomic group, DWVan
Klevelen “Properties of Polymers” (Elsevier,
It can be obtained by calculating from the formula Sp=(〓Eni/〓Vi) ^1/2 (cal/cm ³ ) ^1/2 using the values described in (1972). Examples of the anionic surfactant (iii) include primary higher fatty acid salts, secondary higher fatty acid salts, primary higher alcohol sulfate ester salts, secondary higher alcohol sulfate ester salts, and primary higher alkyl sulfonates. , secondary higher alkyl sulfonate, higher alkyl disulfonate, sulfonated higher fatty acid salt, higher fatty acid sulfate ester salt, higher fatty acid ester sulfonate, higher alcohol ether sulfate ester salt, higher alcohol ether sulfonate Any anionic surfactant may be used, such as alkylolated sulfate ester salts of higher fatty acid amides, alkylbenzene sulfonates, alkylphenolsulfonates, alkylnaphthalene sulfonates, and alkylbenzimidazole sulfonates. More specific compound names of these surfactants are disclosed, for example, in "Synthetic Surfactants" by Hiroshi Horiguchi (published by Sankyo Publishing in 1972). In the aqueous dispersion according to the invention, each of the above-mentioned components is present in a certain range of quantitative ratios. That is, 1 part by weight of thermoplastic polymer (ii) per 100 parts by weight of thermoplastic resin (i).
from 1 to 60 parts by weight, especially from 2 to 50 parts by weight, and from 1 to 40 parts by weight of anionic surfactant (iii), especially from 2 to 30 parts by weight.
It is preferable that each component is present in a proportion of parts by weight. When component (ii) is below this ratio, the thermoplastic resin is not sufficiently dispersed, and when it is above this ratio, the dispersion results in a dispersion that differs from the original properties of the desired thermoplastic resin. When component (iii) is below this proportion, it becomes difficult to obtain ultra-fine dispersed particles as intended in the present invention, and when this proportion is exceeded, the physical properties of the coating film tend to deteriorate. The aqueous dispersion according to the present invention further contains water in addition to the above structure, and in a dispersion that can be handled as a solid, the water content is 3 to 25% by weight in the aqueous dispersion. If the water content is less than 3% by weight, an aqueous dispersion cannot be obtained, and if it exceeds 25% by weight, a fluid aqueous dispersion will be obtained. That is 3
By being in the range of ~25% by weight, it becomes solid in many cases and also exhibits the properties described below. Of course, according to the present invention, a dispersion in the form of a fluid aqueous dispersion can also be prepared, in which case the water content may be 35% by weight or more. Method for producing an aqueous dispersion The first step in the production method of the present invention consists of melt-kneading the thermoplastic resin (i), thermoplastic polymer (ii), and anionic surfactant (iii). At this time, it should be noted that it is important to simultaneously melt and knead the three components (i), (ii), and (iii) above in order to perform phase inversion. A method in which an aqueous solution of an anionic surfactant is successively added to a kneaded resin does not cause phase inversion, and an aqueous dispersion cannot be obtained. The blending ratios of the thermoplastic resin (i), thermoplastic polymer (ii), and anionic surfactant (iii) are as described above. The temperature for melt-kneading is at least higher than the higher melting point of the thermoplastic resin or the thermoplastic polymer. If the melting point is not clear, the temperature at which the melt viscosity is at least 10 ⁵ poise or less is used as the standard. The second step of the production method of the present invention is a step of neutralizing or saponifying a predetermined amount of thermoplastic polymer (ii) by adding a basic substance and water, and at the same time inverting the phase of the resin solid content into an aqueous dispersion. . As the basic substance, those mentioned above are used, but two or more types of these may be used. The basic substance is usually added in the form of an aqueous solution. In this process, a basic substance reacts with the thermoplastic polymer that was evenly mixed in the first step, causing a neutralization or saponification reaction, resulting in phase inversion even in the presence of a small amount of water added at the same time. A dispersion with an ultrafine particle size is obtained. The amount of basic substance added in this step is such that the carboxylic acid salt produced by neutralization and/or saponification in the thermoplastic polymer (ii) is added per gram of the polymer.

[Formula] Add the amount necessary for neutralization or saponification to 0.1 to 5 mmol equivalent in terms of the group. The amount of water added should be at least 3% by weight of the total amount of the aqueous dispersion obtained. If it is less than 3% by weight, no phase inversion will occur and therefore no aqueous dispersion will be obtained. The upper limit of the amount of water added is not particularly limited, but from the viewpoint of the use of the aqueous dispersion, it is preferably at most 90% by weight. In this melt-kneading step of the present invention, 3 to 25
Thermoplastic resin in the presence of limited moisture in wt%
(i) and thermoplastic polymer (ii) are melt-kneaded,
It is characterized by phase inversion of the resin solid content into an O/W type dispersion. The addition of water to the melt-kneading system is
It may be possible to carry out amounts exceeding 25% by weight up to 90% by weight, but even in this case the phase inversion itself is carried out at a stage where the addition of water is between 3 and 25% by weight. Of course, if the final amount of water added is in the range 3 to 25% by weight, a solid aqueous dispersion will be obtained; if it exceeds 25% by weight, especially if it is 35% or more, a fluid liquid aqueous dispersion will be obtained. A dispersion is obtained. Further, in the present invention, it is extremely important to sequentially add water in an amount of 3 to 25% by weight based on the total amount mentioned above. That is, by performing melt-kneading while sequentially adding small amounts of water, sufficient shear force acts on the resin, causing a phase change from W/O to O/W, resulting in ultrafine dispersion particles. is carried out. For example, if melt-kneading is performed with the above small amount of water present from the beginning, sufficient shearing force will not act on the resin, and ultra-fine dispersion will not occur due to phase inversion. . The speed of the sequential addition of water may be appropriately determined experimentally so as to obtain ultrafine dispersed particles of, for example, 5 microns or less. The obtained aqueous dispersion is then naturally or artificially cooled to room temperature, and the dispersed particles are solidified to obtain a stable dispersion. The melt-kneading means that can be used in the production method of the present invention may be any known method, but preferably a kneader,
Examples include a Banbury mixer and a multi-screw extruder. In this way, the production method of the present invention allows liquid and solid aqueous dispersions to be obtained extremely easily by simply changing the amount of water added, and the average dispersed particle size of the resulting dispersions is 5μ or less. Most of them are in the range of 2μ or less, and in the case of solid aqueous dispersions, they have the characteristic that by adding water, they can easily become a dispersion in which the solid content is dispersed in the aqueous phase. In addition, in the production of the aqueous dispersion and aqueous dispersion of the present invention, various auxiliary materials that are normally used in aqueous dispersions, such as dispersants, emulsifiers, stabilizers, wetting agents, thickeners, and It goes without saying that foaming agents, antifoaming agents, coagulants, gelling agents, anti-aging agents, softeners, plasticizers, fillers, colorants, flavoring agents, anti-blocking agents, mold release agents, etc. may be used in combination. It is about. Structure and properties of aqueous dispersion An important feature of the present invention is that the above-mentioned thermoplastic resin
A molten mixture of (i), a carboxylate type thermoplastic polymer (ii), and (iii) an anionic surfactant undergoes a phase inversion phenomenon in the presence of an extremely small amount of water of 3 to 25% by weight, This is based on the discovery that an O/W type dispersion form in which water is the dispersion medium phase and resin solids are the finely dispersed particle phase is stably fixed. Of course, a liquid dispersion can be obtained by adding an additional amount of water to the aqueous dispersion of the present invention directly during the manufacturing process, or by adding an additional amount of water at a site outside the manufacturing process. , In these cases as well, the phase inversion phenomenon itself is
It may be necessary to note the fact that it is carried out in the presence of small amounts of water, ranging from 3 to 25%. As a result of observing the particle structure using an electron microscope, it was found that the secondary particles of the solid aqueous dispersion of the present invention had a structure in which slightly deformed fine primary particles aggregated quite densely. However, the fact that these primary particles have an oil-in-water (O/W) type dispersion form is proven from various facts described below. Another property of the aqueous dispersion is that its electrical resistance value is
10 ⁶ Ω・cm or less Most of them show 10 ⁵ Ω・cm or less. The reason for such a low electrical resistance value is presumed to be that the continuous phase of the dispersion is water and the discontinuous phase is resin. In other words, if the continuous phase is a resin or if the resin powder simply contains less than 25% water by weight, the electrical resistance value will be the same as the resin's original value (generally 10 ⁷ to 10 ¹⁸
Ω・cm, often 10 ¹⁰ Ω・cm or more). Another characteristic is that when water is added to an aqueous dispersion, solid components are uniformly dispersed in the aqueous phase. This also suggests that it is a dispersion in which the continuous phase is water. To measure the electrical resistance value, attach 1 cm ² electrodes on both opposing sides of a 1 cm cubic insulator container.
After press-fitting the dispersion, the resistance value between the electrodes is measured using an AC resistance measuring device at 60 Hz. To measure the state of dispersion by adding water, the dispersion is poured into cold water, stirred with an ordinary stirrer equipped with turbine blades, and then filtered through a wire mesh of approximately 100 mesh, and the particles in the dispersion are examined using a microscope, etc. This can be confirmed by observation. The dispersed particles of the dispersion of the present invention are substantially spherical particles, with an average particle size in the range of 5μ or less, often 2μ or less. This particle size can be measured using a Coulter counter. When the solid aqueous dispersion was redispersed in water and the water was then dried to reduce the solid content only, an electron micrograph was observed, and it was found that the solid particles were substantially spherical fine particles. The aqueous dispersion according to the present invention has a low water content and is solid in appearance, and can be easily turned into an aqueous dispersion by adding water, so there is no risk of freezing, saving space in storage areas, and facilitating transportation. It has characteristics such as ease of packaging. Furthermore, it can also be mixed into powders and granules that do not come into contact with water, such as cement, mortar, and plaster. It can also be used as a sealing material. In addition, as another usage mode of the aqueous dispersion of the present invention, it is possible to apply an extremely small shearing force or dry it under extremely mild temperature conditions to make it fine powder and reduce the water content. It can also be used as a binder for new ceramics and as a polymer modifier. Effects of the Invention According to the present invention, as detailed above, the thermoplastic resin (i), the neutralizable and/or saponifiable thermoplastic polymer (ii), and the anionic surfactant are melt-kneaded, and then By simply adding a basic substance and a small amount of water and continuing melt-kneading, the phase inversion in which the resin solid content becomes a finely dispersed particle phase is easily carried out, and the aqueous dispersion formed is It has the advantage that it can be handled as a solid with a low water content, is easily dispersed in water, and can form a film with excellent water resistance, oil resistance, chemical resistance, and adhesion to hydrophobic materials. be. Examples Preferred examples of the present invention are shown below, but the present invention is not limited to these examples unless otherwise specified. Example 1 Ethylene-vinyl acetate copolymer resin (vinyl acetate content = 19 wt%, MFR = 150
g/10 min, density = 0.97 g/cm ³ , Sp value = 8.06 (cal/
cm ³ ) ^1/2 100 parts by weight and maleic anhydride grafted polyethylene (maleic anhydride content = 3.3 wt%,

[Formula] Group = 0.67 mmol equivalent/g, Mw = 2700, Density = 0.94 g/cm ³ , Sp value =
8.06 (cal/cm ³ ) ^1/2 ) and 5 parts by weight of potassium oleate as an anionic surfactant are placed in a pressure kneader and melt-kneaded at 140° C. for 30 minutes. Next, 20 parts by weight of alkaline water in which 0.38 parts by weight (1.0 chemical equivalents) of potassium hydroxide, which is necessary to neutralize all the carboxylic acids in the thermoplastic polymer, is dissolved is added using a pump connected to the kneader for 5 minutes. Press fit.
The pressure inside the kneader became 3Kg/cm ² G. after that
After continuing kneading for 30 minutes, the kneader was cooled to 60°C and the contents were taken out. The contents were a white solid. This white solid was filled into a 1 cm cubic container, and its electrical resistance was measured to be 2×10 ³ Ω·cm. Also, 8 parts by weight of the white solid was poured into 10 parts by weight of water, and after stirring with a turbine blade stirrer, the dispersion was mixed.
Although it was passed through a 100mesh wire mesh, no residue was observed. The dispersion has a solid content concentration of 36wt% and a viscosity of 110cpsPH.
9.9, and when the size of the dispersed particles was measured using a Coulter counter, the average particle size was 0.6μ.
In addition, the amount of carboxylate produced in the thermoplastic polymer was quantified using an infrared spectrophotometer.

[Formula] It was 0.50 mmol equivalent/g in terms of group. Examples 2 to 12 The composition ratios shown in Table 1 were the same as in Example 1.
The results are shown in Table 1. Example 13 The ethylene-vinyl acetate copolymer resin used in Example 1 and the maleic anhydride grafted polyethylene were added from the hopper of a co-rotating meshing twin-screw extruder (manufactured by Ikegai Iron Works, PCM-30 L/D=20). A mixture of potassium oleate in the ratio of 100/10/5
6.3 parts by weight of potassium hydroxide was supplied at a rate of 115 parts by weight/hour, and 6.3 parts of potassium hydroxide was
% aqueous solution was continuously supplied at a rate of 6 parts by weight/hour, and extrusion was carried out continuously at a heating temperature of 90°C. The product was a white solid whose properties are shown in Table 1. Example 14 In Example 1, 20 parts by weight of alkaline water in which 0.38 parts by weight of potassium hydroxide had been dissolved was injected using a pump, and then 90 parts by weight of water was continuously injected and melt-kneaded. Thereafter, the kneader was cooled and the contents were taken out. The contents are a white liquid with resin uniformly dispersed, solid content concentration 49wt%, viscosity 1250cps, PH10.0,
The average size of the dispersed particles was 0.6μ. In addition, the amount of carboxylic acid salts produced in thermoplastic polymers was quantified.

[Formula] It was 0.51 mmol equivalent/g in terms of group. Example 15 The maleic anhydride grafted polyethylene used in Example 1 was made into a neutralized product by the method shown in the following reference example. 10 parts by weight of the neutralized product, 100 parts by weight of the ethylene-vinyl acetate copolymer resin shown in Example 1, and 5 parts by weight of potassium oleate were placed in a pressure kneader,
Melt and knead at 140°C for 30 minutes. Next, using a pump connected to the kneader, 20 parts by weight of water was pumped in for 5 minutes. The pressure inside the kneader became 3Kg/cm ² G. After continuing kneading for 30 minutes, the kneader was cooled and the contents were taken out. The contents were a white solid. When this white solid was evaluated in the same manner as in Example 1, it was found to have a water content of 14%, an electrical resistance of 6×10 ³ Ω·cm, good dispersibility, and an average particle size of 0.8 μm. Reference Example 100 parts by weight of maleic anhydride-grafted polyethylene is placed in a normal pressure kneader and melt-kneaded at 140°C. Next, 3.8 parts by weight of potassium hydroxide

19 parts by weight of alkaline water in which 1.0 chemical equivalent for the group [formula] was dissolved was gradually added dropwise, and after the water had evaporated, kneading was continued for an additional 30 minutes and the mixture was cooled. Quantification of the produced carboxylic acid salt

[Formula] Substitution The total amount was 0.66 mmol equivalent/g.

【table】

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Claims (1)

[Scope of Claims] 1 (i) a thermoplastic resin; (ii) a neutralizable and/or saponifiable carboxylic acid, anhydride or ester group bonded to the polymer chain in one gram of the polymer; a step of melt-kneading a thermoplastic polymer containing a concentration of 0.1 mmol equivalent or more in terms of -COO- groups, and (iii) an anionic surfactant; By sequentially adding % by weight of water and performing melt-kneading, 0.1 to 5 mmol equivalent of carboxylate groups, calculated as -COO- groups, are formed in the thermoplastic resin (i) per gram of the resin. and a step of inverting the phase of the dispersion medium from resin to water to obtain an aqueous dispersion, and adding an additional amount of water to the aqueous dispersion if necessary. 2 A patent claim in which the thermoplastic polymer (ii) is used in an amount of 1 to 60 parts by weight and the anionic surfactant (iii) is used in an amount of 1 to 40 parts by weight per 100 parts by weight of the thermoplastic resin (i). The manufacturing method according to item 1. 3 The thermoplastic resin (i) and the thermoplastic polymer (ii)
means that the difference in solubility parameter (Sp value) is 2
(cal/cm ³ ) ^1/2 or less is used.