JPH0735479B2 - Aqueous dispersion and method for producing the same - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an aqueous dispersion of a resin and a method for producing the same, and more specifically, although it is apparently solid, the resin solid content in water is changed by water addition. The present invention relates to an aqueous dispersion having the property of being finely dispersed in water and a method for producing the same.

(Prior Art) Aqueous dispersions of various polymers have been conventionally known. A fluid aqueous dispersion having a water content of, for example, about 30% by weight or more (hereinafter referred to as an aqueous dispersion) is a paper, a fiber or a plastic molded article, wood,
Apply on the surface of metal etc. and dry to form a resin film,
It is used to impart water resistance, oil resistance, and chemical resistance to base materials, and is used as a heat sealant. Since such an aqueous dispersion uses water as a dispersion medium, it is very advantageous and has a wide range of fields from the solvent type in terms of flammability, working environment and handling. It is used in.

In order to make a hydrophobic thermoplastic resin into an aqueous dispersion, it is generally necessary to use a surfactant, and for example, a method of making a thermoplastic resin into an aqueous dispersion by using a nonionic surfactant is already known. (For example, Japanese Examined Patent Publication No. 57-23702).

(Problems to be Solved by the Invention) However, when a thermoplastic resin is used as an aqueous dispersion using a nonionic surfactant, it is difficult to convert the resin into fine particles, and To obtain it, a large amount of nonionic surfactant and a large amount of water were required.

If the aqueous dispersion is made to be apparently solid, and it is made into fine particles and dispersed in water simply by adding water, there is no fear of freezing, and it is possible to save storage places and containers and to facilitate transportation. Many advantages are achieved in. Further, it is desirable to reduce the amount of the surfactant in the aqueous dispersion as much as possible in order to improve the humidity sensitivity of the coating formed from the aqueous dispersion.

Therefore, the present invention solves the above-mentioned drawbacks of the conventional method of producing an aqueous dispersion of a resin using a nonionic surfactant, and while the resin solid is apparently solid, oil-in-water (O / W) An object of the present invention is to provide an aqueous dispersion which has been phase-inverted into a mold dispersion and which can easily form fine dispersed particles of a resin by hydration, and a production thereof.

(Means for Solving Problems) The present inventors use a polymer containing a carboxylic acid or a salt group thereof and a specific nonionic surfactant in combination with a hydrophobic thermoplastic resin. It was found by the phase inversion method that an aqueous dispersion having a small water content and a particle size controlled in a minute range can be obtained.

According to the present invention, (i) a hydrophobic thermoplastic resin, (ii) a concentration of carboxylic acid or carboxylate group bonded to a polymer chain of 0.1 to 5 millimolar in terms of —COO— group per 1 g of the polymer. Or a water-insoluble thermoplastic polymer containing a carboxylic acid derivative group that can be generated so that the concentration of the group falls within the above range by a base treatment, (iii) a nonionic surfactant having an HLB of 10 or more, iv) water, and (v) if necessary, when a thermoplastic polymer requiring a base treatment is present, the basic substance is melt-kneaded, and the resin solid content is phase-inverted into an aqueous dispersion. A method for producing an aqueous dispersion is provided.

According to the present invention, further, (i) a hydrophobic thermoplastic resin, (ii) a group of carboxylic acid or a salt thereof bound to a polymer chain, in a concentration of 0.1 to 5 millimolar in terms of —COO— group per 1 g of the polymer. A water-insoluble thermoplastic polymer containing (iii) HLB containing 10 or more nonionic surfactants and (iv) water, and is apparently solid and has the property of being dispersed in water by water addition. An aqueous dispersion is provided.

(Function) In the present invention, when a hydrophobic thermoplastic resin is combined with a polymer containing a carboxylic acid or a salt thereof and a nonionic surfactant and melt kneading is performed in the presence of a small amount of water, it is conventionally known. It is based on the finding that an aqueous dispersion having a significantly fine dispersed particle size can be obtained as compared with the above method.

This fact will be clarified by comparing and comparing an example and a comparative example described later, and the present inventor estimates the reason as follows. That is, in the composition of the present invention, the main action of inversion of the hydrophobic thermoplastic resin (i) into the oil-in-water (O / W) type dispersion is that the carboxylate of (ii) A thermoplastic polymer containing a group, wherein
The nonionic surfactant of i) promotes this phase inversion action and stabilizes the aqueous dispersion. In this composition, the carboxylate group of the thermoplastic polymer (ii) has a strong affinity for water (iv), while the polymer chain of the polymer (ii) has a hydrophobic thermoplastic resin (i). ) Shows an affinity for. The nonionic surfactant (iii) acts to reduce the surface tension of water. Then, when this composition is melt-kneaded, water is dispersed in the resin in a state where the surface tension is lowered by the nonionic surfactant, and moreover, the water is drawn into the carboxylate group of the thermoplastic polymer (ii), It is believed that the surface tension of the molten resin causes the carboxylate groups to be oriented to the outer surface, and the nonionic surfactant and the hydration layer are adhered as a thin film to form a granular form. .

In the aqueous dispersion of the present invention, the amount of water is as small as 3 to 25% by weight, and the fact that it exists as an oil-in-water type dispersion although it is apparently solid means that its electric resistance value is 10 ⁶ Ωcm or less, Most of them are as low as 10 ⁵ Ωcm or less, and such low electrical resistance is achieved only when the aqueous phase is a continuous phase. It is confirmed that they are uniformly dispersed as fine particles.

In the present invention, an additional amount of water may be added to the composition described above to form a liquid dispersion having a water content of more than 25% by weight, but in this case as well, phase inversion, i.e. oil in water. It should be noted that the formation of the mold dispersion itself is carried out in the presence of the limited water content mentioned above.

It should also be understood that the formation of the carboxylate groups in polymer (ii) can be carried out prior to compounding the components or during melt blending. In the latter case, a carboxylic acid ester, a carboxylic acid anhydride or a polymer having a carboxylic acid may be mixed with a basic substance to form a salt in the presence of water.

DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION The present invention is described in detail below.

Blending component The thermoplastic resin (i), which is one of the components constituting the aqueous dispersion of the present invention, is not only insoluble in water and non-swelling in water, but also lacks dispersibility in water. Resin, such as low density polyethylene, high density polyethylene,
Polypropylene, poly 1-butene, poly 4-methyl-1
-Polyene such as pentene or random or block copolymer of α-olefins such as ethylene, propylene, 1-butene and 4-methyl-1-pentene, ethylene / vinyl acetate copolymer, ethylene / vinyl alcohol copolymer , Ethylene / vinyl compound copolymer such as ethylene / vinyl chloride copolymer, polystyrene, acrylonitrile / styrene copolymer, ABS, styrene resin such as α-methylstyrene / styrene copolymer, polyvinyl chloride, polychlorination Vinylidene, vinyl chloride / vinylidene chloride copolymer, polyvinyl compounds such as polymethyl acrylate, polymethyl methacrylate, nylon 6, nylon 6-6, nylon 6-10, nylon 11, nylon 12
Any resin such as polyamide, polyethylene terephthalate, thermoplastic polyester such as polybutylene terephthalate, polycarbonate, polyphenylene oxide, etc., or a mixture thereof may be used.

Among these thermoplastic resins, olefin resins are particularly preferable, that is, polyethylene, polypropylene,
Poly-1-butene, poly-3-methyl-1-butene, poly-4-methyl-1-pentene, poly-3-methyl-1
-Pentene, ethylene / propylene copolymer, ethylene / 1-butene copolymer, ethylene represented by propylene / 1-butene copolymer, propylene, 1-butene, 3
-Methyl-1-butene, 4-methyl-1-pentene, 3
-Methyl-1-pentene, 1-heptene, 1-hexene, 1-decene, 1-dodecene, or other α-olefin homopolymers or copolymers, or ethylene / butadiene copolymers or ethylene / ethylidene norbornene copolymers. Representative copolymers of α-olefin and conjugated or non-conjugated diene, ethylene / propylene / butadiene terpolymer, ethylene / propylene / dicyclopentadiene terpolymer, ethylene, propylene / ethylidene norbornene Α represented by terpolymer, ethylene / propylene / 1,5-hexadiene terpolymer
-Copolymers of two or more olefins and a conjugated diene or a non-conjugated diene. Among them, particularly preferable are α-olefin homopolymers or copolymers.

Melt flow rate of thermoplastic resin (i) (ASTMD123
8, MFR) is 1 g / 10 min or more, preferably 5 g / 10 min or more. When the MFR is less than 1 g / 10 min, the melt viscosity becomes too large and it becomes difficult to melt-knead, and it is difficult to obtain a suitable aqueous dispersion.

The thermoplastic polymer (ii) which is another component constituting the aqueous dispersion of the present invention is a carboxylic acid group which is neutralized or is not neutralized by the above-mentioned thermoplastic resin or the monomer constituting the thermoplastic resin. Or a monomer having a saponified or non-saponified carboxylic acid ester group is introduced by means of graft copolymerization, block copolymerization, random copolymerization, etc. Neutralization reaction or saponification reaction is carried out by the substance, and the total amount of carboxylate formed in the polymer is added to 1 gram of the polymer. It is adjusted so as to contain 0.1 to 5 mmol equivalent, particularly 0.2 to 4 mmol equivalent in terms of conversion. In this case, the polymer may be a partially neutralized product or partially saponified product in which carboxylic acid groups or carboxylic acid ester groups which are not neutralized or saponified coexist. Also, the thermoplastic polymer (ii) must not be water-soluble or water-swellable. When the total amount of the neutralized carboxylic acid group and / or the saponified carboxylic acid ester group is outside the above range, it does not function to help disperse the thermoplastic resin (i) and a good dispersion is obtained. And can't. If it is water-soluble or water-swellable, the physical properties of the coating film deteriorate.

The above-mentioned thermoplastic polymer (ii) is post-neutralized or post-saponified.
In this case, the raw material polymer is, for example,
Monomers that are common to the monomers that make up the plastic resin (i),
Α-olefin and ethylenically unsaturated carboxylic acid or
A copolymer of the ester,
(Meth) acrylic acid, maleic acid, fumar as boric acid
Acid, tetrahydrophthalic acid, itaconic acid, citracone
Acid, crotonic acid, isocrotonic acid, nadic acid (En
Docis-bicyclo [2,2,1] hept-5-ene-2,3-di
Carboxylic acid), maleic anhydride, citraconic anhydride, etc.,
As the unsaturated carboxylic acid ester, the above-mentioned unsaturated carboxylic acid
Monoesters of acids such as methyl, ethyl, propyl, etc.
A steal etc. can be illustrated. Of course, multiple monomer components can be used together
Instead of combining, a thermoplastic resin (i) such as an olefin
Ethylenically unsaturated carboxylic acid, its anhydride or
Or to graft-polymerize the monomers such as ester
Yields a thermoplastic polymer for post-neutralization or post-saponification.
It will be obvious to those skilled in the art.

The amount of these ethylenically unsaturated carebonic acids, their anhydrides, or their ester monomers introduced should, of course, be sufficient to give the concentration of carboxylate salt specified above. No As a minimum concentration of 0.1 mmol / 1 g polymer, preferably in the range of 0.1-5 mmol / 1 g polymer.

The basic substances used for neutralization and saponification include alkali metals, alkaline earth metals, substances that act as bases in water such as ammonia and amines, alkali metal oxides, hydroxides, weak acid salts, and hydrides. Examples thereof include substances that act as bases in water, such as 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,
Examples of potassium and alkaline earth metals are calcium, strontium and barium, (2) Examples of amines are hydroxylamine and inorganic amines such as hydrazine, methylamine, ethylamine, ethanolamine, cyclohexylamine, (3) Alkali metals and alkalis Examples of oxides, hydroxides, and hydrides of earth metals include sodium oxide, sodium peroxide, potassium oxide, potassium peroxide, calcium oxide, strontium oxide, barium oxide, sodium hydroxide, potassium hydroxide, and hydroxide. Calcium, strontium hydroxide, barium hydroxide, sodium hydride, potassium hydride, calcium hydride, (4) Weak acid salts of alkali metals and alkaline earth metals include sodium carbonate, potassium carbonate and sodium hydrogen carbonate. , Potassium hydrogencarbonate, calcium hydrogencarbonate, sodium acetate, potassium acetate, calcium acetate, (5) Examples of ammonia and amine compounds include ammonium hydroxide, quaternary ammonium compounds such as tetramethylammonium hydroxide and hydrazine hydrate. Etc. can be mentioned.

As the carboxylic acid group or calebonic acid ester group neutralized or saponified with a basic substance, sodium carboxylates, alkali metal salts of carboxylic acids such as potassium carboxylates, ammonium carboxylates are preferable, and potassium carboxylates are particularly preferable. preferable.

As the thermoplastic polymer (ii), it is preferable to select one having a good compatibility with the target heat-depopulated thermoplastic resin (i). That is, when an aqueous dispersion of an olefin resin is intended, a polymer containing an olefin monomer in its main chain should be selected. For example, polyethylene or polyolefin,
When using ethylene-vinyl acetate copolymer, etc., these maleic acid graft products or ethylene
It is preferable to use a neutralized product or a saponified product such as a (meth) acrylic acid copolymer or an ethylene / (meth) acrylic acid methyl copolymer. This is an index solubility parameter (Sp value) which is one index when selecting an appropriate thermoplastic polymer. That is, the difference in solubility parameter between the raw material polymer and the thermoplastic resin (i) before being neutralized or saponified is 2
It is preferably within [cal / cm ³ ] ^1/2 , particularly preferably within 1 [cal / cm ³ ] ^1/2 .

In the present specification, the solubility parameter (Sp value) is
It has the usual meaning, that is, the value defined as the half power of the cohesive energy density. The solubility parameter is the contribution value Vi of the atomic group to the molar volume and the cohesive energy En of the atomic group En.
DWVan Klevelen “Properties of Polymers” (Els
evier, 1972) using the values Calculated from

As the nonionic surfactant used in the present invention, HLB is 1
A nonionic surfactant having an HLB of 0 or more, particularly preferably 13 or more, is used. The nonionic surfactants may be used alone or in a combination of two or more kinds. In the case of a combination of two or more kinds, the HLB of the mixture may be within the above range. Examples of nonionic surfactants include polyoxyethylene alkyl ether, polyoxyethylene alkylphenyl ether, polyoxyethylene fatty acid ester, polyoxyethylene fatty acid amide ether, polyhydric alcohol fatty acid ester, polyoxyethylene polyhydric alcohol fatty acid ester, and fatty acid ester. Among the sugar esters, alkylolamides, polyoxyalkylene block copolymers and the like, those having HLB within the above range are used. For example,
In these nonionic surfactants, HLB generally increases as the content of polyoxyethylene units increases.
A desired nonionic surfactant of HLB can be obtained by adjusting the number of moles of ethylene oxide added.

In the present invention, the composition may contain an organic solvent or an oil agent, if desired.

Any organic solvent may be used as long as it can dissolve (swell) the thermoplastic resin (i) and the thermoplastic polymer (ii), and examples thereof include benzene, toluene, xylene, styrene, α-methylstyrene, and divinylbenzene. And the like, aliphatic hydrocarbons such as hexane and heptane, and halogenated hydrocarbons such as trichloroethylene. This organic solvent may be contained in the final aqueous dispersion, or may be removed from the final aqueous dispersion by a means such as distillation or azeotropic distillation. For example, when removing by distillation, the boiling point of the solvent is preferably 100 ° C. or lower.

This organic solvent is one that swells or partially dissolves the thermoplastic resin (a), and may be in a remarkably small amount unlike the conventional solvent method.

As the natural oil or synthetic oil used as an optional component,
Mineral lubricants such as spindle oil and machine oil, mineral oils such as liquid paraffin, electric insulating oil and process oil; synthetic oils such as alkylbenzene oil, diolefin oil, diester oil and alkylnaphthenate oil; castor oil, linseed oil , Vegetable oils such as rapeseed oil, coconut oil and tall oil are used.
These oil agents are stably held in the resin solid content,
It should have a number average molecular weight of 200 or more.

Composition, Structure and Properties of Aqueous Dispersion The ratio of the thermoplastic resin (i) to the thermoplastic polymer (ii) is such that the thermoplastic polymer (ii) is 100 parts by weight of the thermoplastic polymer (ii). ) Is 1 to 60 parts by weight, particularly preferably 2 to 50 parts by weight. When (ii) is less than this ratio, the dispersion of the thermoplastic resin (i) is not sufficient, and when it is more than this ratio, the desired thermoplastic resin (i) is different from the original dispersion. Become.

The nonionic surfactant is preferably used in an amount of 0.1 to 40 parts by weight, particularly 0.2 to 20 parts by weight, per 100 parts by weight of the thermoplastic resin. If this amount is less than the above range, the effects of dispersion promotion and dispersion stability will be inferior to those in the above range. On the other hand, if used in excess of the above range, the formed coating film, etc. It becomes humidity sensitive and economically disadvantageous.

The aqueous dispersion of the present invention has the above composition and further contains water. The water content (water content based on the whole) is 3 to 90% by weight, particularly 5 to 70% by weight in the aqueous dispersion. Is.

One type of the present invention, an aqueous dispersion, ie an apparently solid aqueous dispersion, contains from 3 to 25% by weight of water. If the water content is less than 3% by weight, an aqueous dispersion cannot be obtained and
When it exceeds%, a fluid aqueous dispersion is obtained. That is 3
When it is in the range of up to 25% by weight, it becomes apparently solid and has the properties described below.

From the electron micrograph of the solid aqueous dispersion according to the present invention, it is understood that the secondary particles of the aqueous dispersion have a structure in which finely deformed fine primary particles are considerably densely aggregated. However, the fact that the primary particles have an oil-in-water type dispersion form is proved by various facts described below.

Another property of aqueous dispersions is that their electrical resistance values are below 10 ⁶ Ωcm, often below 10 ⁵ Ωcm. It is presumed that such a low electric resistance value is due to the fact that the continuous phase of the dispersion is water and the discontinuous phase is resin. That is, if the continuous phase is resin or resin powder
When the content of water is 25% by weight or less, the electric resistance value thereof is the value that the resin originally has (generally 10 ⁷ to 10 ¹⁸ Ωcm, most of which is 10 ¹⁰ Ωcm or more).

As another property, when water is added to the aqueous dispersion, the solid content is uniformly dispersed in the aqueous phase. From this, it is estimated that the continuous phase is a dispersion containing water.

In addition, the measurement of the electrical resistance value here was performed by pressing electrodes of 1 cm on both sides facing each other in a 1 cm cubic insulator container and pressing the dispersion to measure the resistance value between the electrodes using 60 Hz of an AC resistance measuring device. Depends on the method of measurement. To measure the dispersion state by adding water, put the dispersion in cold water and stir it with an ordinary stirrer having a turbine blade, then filter the dispersion with a wire mesh of about 100 mesh and disperse the particles in the dispersion with a microscope etc. It can be confirmed by observing.

Dispersed particles of the dispersion of the present invention, when dispersed in water by water, are substantially spherical particles, the average particle size is 10μ
Below, many are in the range of 5μ or less.

This particle size can be measured using a Coulter counter.

Production of Aqueous Dispersion The aqueous dispersion of the present invention has the above (i), (ii), (iii)
It can be produced by melt-kneading the components (iv) and (iv).

As the component (ii), it is natural that one having a carboxylate group can be used, but in general, an unneutralized carboxylic acid, an anhydride thereof or one having an ester group thereof is neutralized, Neutralizing and phase inversion of the resin in the melt-kneading step is advantageous in terms of the number of steps and economical efficiency.

In this production method, a plurality of types of resins are melt-kneaded, but the temperature during melt-kneading is higher than the melting point of the higher resin used, preferably the melt viscosity is 10 ⁶ poises or less, particularly 10 ⁵ poise or less. It is above the temperature. Also component (d)
When (2) and (e) are used in combination, the temperature does not have to be higher than the melting point of the resin as long as the viscosity of the composition is in the above range.

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, a Banbury mixer, or a multi-screw extruder can be exemplified.

In any of these methods, in the melt-kneading step, the melt-kneading of the thermoplastic resin (i) and the thermoplastic polymer (ii) is performed in the presence of limited water of 3 to 25% by weight. The characteristic is that phase inversion of the resin solid content into an O / W type dispersion is performed. Water may be added to the melt-kneading system in an amount of more than 25% by weight and up to 90% by weight. Even in this case, the phase inversion itself should be performed by adding 3 to 25% of water.
It is carried out at the weight% stage. Of course, when the final amount of water added is in the range of 3 to 25% by weight, a solid aqueous dispersion is obtained,
When it exceeds 25% by weight, and particularly when it exceeds 35%, a fluid aqueous dispersion is obtained. The upper limit of the amount of added water is not particularly limited, but it is at most 90 due to the use of the aqueous dispersion.
Up to wt% is preferred.

When the basic substance is added later, the above-mentioned basic substance may be added directly, but it is preferable to add it in the form of an aqueous solution. The amount of the basic substance added is such that the carboxylic acid salt formed by neutralization and / or saponification in the thermoplastic polymer (b) is added to 1 gram of the polymer. It is the amount necessary for neutralization or saponification so that it becomes 0.1 to 5 mmol equivalent in terms of conversion.

The aqueous dispersion produced by melt-kneading by sequentially adding water,
After that, it is cooled to room temperature naturally or artificially. At this time, the dispersed particles solidify to form a stable dispersion. When a solvent is used, it is removed by means such as evaporation if necessary.

In the production of this dispersion, various auxiliary materials that can be usually used in an aqueous dispersion, such as a dispersant such as an anionic surfactant or a nonionic surfactant, an emulsifier, a stabilizer, a wetting agent, a thickener, Of course, a foaming agent, an antifoaming agent, a coagulant, a gelling agent, an antiaging agent, a softening agent, a plasticizer, a filler, a coloring agent, a fragrance, an anti-sticking agent, a release agent, etc. may be used in combination. That is.

(Effects of the Invention) The solid-type aqueous dispersion of the present invention has a low water content and is apparently solid, and since it is easily converted into an aqueous dispersion by addition of water, there is no fear of freezing and space saving of storage space is possible. It has features such as ease of transportation, ease of packaging, and so on. In addition, it is possible to mix the diameter of powder, such as cement, mortar, or gypsum, into powders or granules that do not interfere with water, and to form a water-resistant, oil-resistant, or chemical-resistant film on various materials with a re-dispersed liquid, or heat it. It can also be used as a sealing material. Further, 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 an extremely mild temperature condition to reduce the pulverization and the water content. In addition, it can be used for applications such as binders for new ceramics and polymer modifiers.

Example of fine powder containing nonionic surfactant Example 1 Low density polyethylene (density = 0.915 g as a thermoplastic resin)
/ cm ³ , MFR = 70 g / 10 min, Sp value = 7.80 (cal / cm ³ )) 100 parts, and as a thermoplastic polymer, maleic anhydride grafted polyethylene (maleic anhydride content = 3.3 wt%, -COO- Group = 0.67 mmol equivalent / g, density = 0.94 g / cm ³ Sp value = 0.06 (cal / c
m ³ )) 10 parts, Emulgen 43 as a nonionic surfactant
5 parts of 0 (HLB = 16.2, manufactured by Kao Corporation) is put into a pressure type kneader and melt-kneaded at 140 ° C. for 30 minutes.

Next, 4 parts of water is pressed in for 5 minutes using a pump connected to a kneader. The pressure inside the kneader was 3 kg / cm ² G.

After continuing kneading for 30 minutes, the kneader was cooled to 60 ° C. and the contents were taken out. The content was a white solid. This white solid was filled in a 1 cm cubic container, and its electric resistance was measured and found to be 6 × 10 ⁴ Ωcm. Also, white solid 1
0 parts by weight was poured into 10 parts by weight of water and stirred with a turbine blade stirrer, and then the dispersion was filtered through a 100 mesh wire net, but no residue was observed.

The dispersion had a solid content concentration of 48 wt%, a viscosity of 230 cps, and a pH of 7.7, and the size of dispersed particles was measured by a Coulter counter to find that the average particle size was 1.3 μm.

Example 2 100 parts of the same low density polyethylene as used in Example 1,
10 parts of maleic anhydride-grafted polyethylene is put into a pressure type kneader and melt-kneaded at 140 ° C. for 30 minutes.

Next, using a pump connected to a kneader, 20 parts by weight of an aqueous surfactant solution in which 5 parts of the same nonionic surfactant as used in Example 1 was dissolved is pressed in for 5 minutes. The pressure inside the kneader was 3 kg / cm ² G.

After continuing kneading for 30 minutes, the kneader was cooled to 60 ° C. and the contents were taken out. The content was a white solid. The electrical resistance and average particle size of this white solid were measured by the same method as in Example 1. The electrical resistance was 7 × 10 ³ Ωcm and the average particle size was 2.3.
It was μ.

Example 3 100 parts of the same low density polyethylene as used in Example 1,
10 parts of maleic anhydride-grafted polyethylene and 5 parts of nonionic surfactant were put into a pressure type kneader and heated at 140 ° C. for 30 minutes.
Melt and knead for a minute.

Next, 0.38 parts (1.0 chemical equivalent) of potassium hydroxide necessary to neutralize all carboxylic acids of the thermoplastic polymer was dissolved 20
Part of the alkaline water is press-fitted for 5 minutes using a kneader-connected pump. The pressure inside the kneader was 3 kg / cm ² G.

After continuing kneading for 30 minutes, the kneader was cooled to 60 ° C. and the contents were taken out. The content was a white solid. The electrical resistance and average particle size of this white solid were measured by the same method as in Example 1. The electrical resistance was 5 × 10 ⁴ Ωcm, and the average particle size was
It was 1.0μ.

Reference Example 1 100 parts by weight of the same maleic anhydride-grafted polyethylene as used in Example 1 is put into an atmospheric pressure kneader and melt-kneaded at 140 ° C. Next, 3.76 parts by weight of potassium hydroxide (-COO
-40 parts by weight of alkaline water in which 1.0 chemical equivalent (based on the group) is gradually added dropwise, and after the water has evaporated, the mixture is kneaded for an additional 30 minutes and cooled.

Example 4 100 parts of the same low density polyethylene used in Example 1,
10 parts of the alkali salt of the thermoplastic polymer obtained in Reference Example 1 is put into a pressure type kneader and melt-kneaded at 140 ° C. for 30 minutes.

Next, using a kneader-connected pump, 20 parts by weight of the surfactant water-soluble, in which 5 parts of the same nonionic surfactant as used in Example 1 was dissolved, was pressed in for 5 minutes. The pressure inside the kneader was 3 kg / cm ² G.

After continuing kneading for 30 minutes, the kneader was cooled to 60 ° C. and the contents were taken out. The content was a white solid. When this solid was dispersed in water and the shape was observed with a microscope, it was found to be true spherical particles. Further, the size of the dispersed particles was measured with a Coulter counter, and it was found that the average particle size was 3.7 μm.

When the electric resistance and the average particle diameter of this white solid were measured by the same method as in Example 1, the electric resistance was 2 × 10 ³ Ωcm and the average particle diameter was 2.3μ.

Example 5 Ethylene-ethyl acrylate copolymer as thermoplastic resin (density = 0.93 g / cm ³ , MFR = 200 g / 10 min, Sp value = 8.22
(Cal / cm ³ )) 100 parts, and as a thermoplastic polymer, ethylene-acrylic acid copolymer resin (AC polyethylene 5120 manufactured by Allied Chemical Co., Ltd., acrylic acid content 15 wt%, -CO
O-group = 2.14 mmol equivalent / g, viscosity (140 ° C.) = 650 cps) 10
Part, 0.3 part of Emanon 3299 (HLB = 18.3, manufactured by Kao Corporation) as a nonionic surfactant is put into a pressure kneader and melt-kneaded at 140 ° C. for 30 minutes.

Next, 1.20 parts (1.0 chemical equivalent) of potassium hydroxide necessary to neutralize all carboxylic acids of the thermoplastic polymer were dissolved 20
Part of the alkaline water is press-fitted for 5 minutes using a kneader-connected pump. The pressure inside the kneader was 3 kg / cm ² G.

After continuing kneading for 30 minutes, the kneader was cooled to 60 ° C. and the contents were taken out. The content was a white solid. The electric resistance and average particle diameter of this white solid were measured by the same method as in Example 1. The electric resistance was 4 × 10 ³ Ωcm and the average particle diameter was 0.9.
It was μ.

Example 6 As a thermoplastic resin, ethylene-vinyl acetate copolymer resin (vinyl acetate content 19 wt% density = 0.97 g / cm ³ , MFR = 150 g / 1
0 minutes, Sp value = 8.06 (cal / cm ³ )) 100 parts, 10 parts of the same maleic anhydride-grafted polyethylene as used in Example 1 as a thermoplastic polymer, Emulgen 985 (HLB = HLB = 18.9) and Emulgen 904 (HLB = 8.
5 parts of a 4: 1 mixture of 9) (HLB after mixing = 16.9) is put into a pressure kneader and melt-kneaded at 140 ° C. for 30 minutes.

Next, 20 parts of water are pressed in for 5 minutes using a pump connected to a kneader. The pressure inside the kneader was 3 kg / cm ² G.

After continuing kneading for 30 minutes, the kneader was cooled to 60 ° C. and the contents were taken out. The content was a white solid. The electrical resistance and average particle size of this white solid were measured by the same method as in Example 1. The electrical resistance was 7 × 10 ³ Ωcm and the average particle size was 1.8.
It was μ.

Example 7 Same-direction rotary meshing twin screw extruder (PC made by Ikegai Tekko Co., Ltd.
From the hopper of M-30 L / D = 20), the low density polyethylene and maleic anhydride grafted polyethylene used in Example 1 and Emulgen 430 (HLB = 1 as a nonionic surfactant) were used.
6.2) was mixed at a rate of 100/10/5 at a rate of 115 polymerization parts / hour, and water was continuously supplied at a rate of 6 parts by weight / hour from a supply port provided in the vent section of the extruder. And heating temperature 14
Extruded continuously at 0 ° C. The extruded resin mixture was cooled to 90 ° C. by a static mixer with a jacket installed at the exit of the extruder and taken out. The product taken out was a white solid. When the electric resistance and the average particle diameter of this white solid were measured by the same method as in Example 1, the electric resistance was 1 × 10 ⁴ Ωcm and the average particle diameter was 2.1 μ.

Example 8 From the same twin-screw extruder hopper as in Example 7,
A mixture of the low-density polyethylene used in Example 1 and the maleic anhydride-grafted polyethylene in a ratio of 100/10 was supplied at a rate of 110 parts by weight / hour, and a nonionic surface active agent was supplied from a supply port provided in the vent section of the extruder. Agent Emulgen 430 (HLB =
The 25 wt% aqueous solution of 16.2) was continuously supplied at a rate of 20 parts by weight / hour and continuously extruded at a heating temperature of 140 ° C. The extruded resin mixture was cooled to 90 ° C. by a static mixer with a jacket installed at the exit of the extruder and taken out. The product taken out was a white solid. When the electric resistance and the average particle diameter of this white solid were measured by the same method as in Example 1, the electric resistance was 7 × 10 ³ Ωcm and the average particle diameter was 2.8 μ.

Comparative Example 1 The same operation as in Example 1 was carried out except that maleic anhydride grafted polyethylene was not used in Example 1 and the amount of water was 20 parts. The content of the kneader was a white solid. The electrical resistance and average particle size of this white solid were measured by the same method as in Example 1. The electrical resistance was 8 × 10 ³ Ωcm and the average particle size was 11.8μ. It was

Claims (2)

[Claims] 1. A hydrophobic thermoplastic resin (i), (ii) a carboxylic acid group or a salt thereof bound to a polymer chain is contained at a concentration of 0.1 to 5 millimolar in terms of --COO-- group per 1 g of the polymer. Water-insoluble thermoplastic polymer, (iii) HLB containing 10 or more nonionic surfactants and (iv) water, and is an apparently solid aqueous dispersion having the property of being dispersed in water by water addition. body. 2. A hydrophobic thermoplastic resin, (ii) a carboxylic acid or carboxylate group bonded to a polymer chain at a concentration of 0.1 to 5 mmol per 1 g of the polymer in terms of --COO-- group. A water-insoluble thermoplastic polymer containing a carboxylic acid derivative group, which contains a carboxylic acid derivative group so that the concentration of the group becomes within the above range by a base treatment, (iii) a nonionic surfactant having HLB of 10 or more, (iv) ) Water, and (v) If necessary, when a thermoplastic polymer requiring a base treatment is present, the basic substance is melt-kneaded, and the resin solid content is phase-inverted into an aqueous dispersion. A method for producing an aqueous dispersion.