JP2011241325A - Manufacturing method of aqueous emulsion - Google Patents

Abstract

PROBLEM TO BE SOLVED: To lessen a particle size of a resin in an aqueous emulsion in order to form a thinner coating surface of a good appearance using an aqueous emulsion material of a smaller amount.SOLUTION: The size of an aggregation particle which exists in an aqueous emulsion can be lessened by a manufacturing method of an aqueous emulsion which includes: an emulsification step which emulsifies a resin in water to obtain an emulsified product; and a pulverizing process which gives a mechanical shear force, an impact force or a friction force to the emulsified product obtained by the emulsification step and grinds the aggregation particle to obtain an aqueous emulsion.

Description

  The present invention relates to a method for producing an aqueous emulsion used for adhesives and paints.

  Aqueous emulsions are generally used for paints and adhesives. For example, Patent Document 1 describes an aqueous emulsion suitable for an adhesive, a coating material, a coating primer, a coating material or a printing binder.

JP 2008-63557 A

  It has been found that when the aqueous emulsion is applied as a paint or an adhesive, the unevenness generated on the coated surface can be suppressed by reducing the size of the aggregated particles present in the aqueous emulsion. In addition, by reducing the size of the agglomerated particles, it becomes possible to form a thinner and uniform coating surface compared to an aqueous emulsion containing large agglomerated particles, and the amount of emulsion required for coating can be reduced. Found that is possible. Therefore, it is important to obtain a water-based emulsion having excellent coatability by reducing the size of aggregated particles present in the water-based emulsion.

Under such circumstances, the present inventors have further studied, and as a result, have reached the invention described below. That is, the present invention
An emulsification step of emulsifying the resin in water to obtain an emulsion;
The present invention relates to a method for producing an aqueous emulsion, comprising a step of applying a mechanical shearing force, impact force or frictional force to the emulsion obtained in the previous step to pulverize the aggregated particles to obtain an aqueous emulsion.

  According to the method of the present invention, the size of agglomerated particles present in an aqueous emulsion can be reduced.

  Examples of the resin suitable for the method of the present invention include a thermoplastic resin. Examples of the thermoplastic resin suitable for the method of the present invention include polyvinyl acetate, polyvinyl alcohol, polyvinyl formal, polyvinyl butyral, acrylic adhesive, polyethylene, chlorinated polyethylene, α-olefin-vinyl compound copolymer, ethylene -Vinyl acetate copolymer, ethylene-vinyl alcohol copolymer, ethylene-ethyl acrylate copolymer, ethylene-acrylic acid copolymer, ionomer, chlorinated polypropylene, polystyrene, polyvinyl chloride, plastisol, vinyl chloride-vinyl acetate A copolymer, polyvinyl ether, polyvinyl pyrrolidone, polyamide, nylon, saturated amorphous polyester, a cellulose derivative, etc. can be mentioned.

The thermoplastic resins suitable for the method of the present invention include in particular:
Structural units derived from ethylene and / or linear α-olefins;
Formula (I)

_{CH 2 = CH-R (I} )

(In the formula, R represents a secondary alkyl group, a tertiary alkyl group, or an alicyclic hydrocarbon group.)
And an olefin copolymer (hereinafter referred to as “polymer (A-1)”) containing a structural unit derived from a vinyl compound represented by the formula (hereinafter sometimes referred to as “vinyl compound (I)”). Or a polymer obtained by graft polymerization of an α, β-unsaturated carboxylic acid anhydride to the polymer (A-1) (hereinafter sometimes referred to as “polymer (A-2)”). Hereinafter, the polymer (A-1) and the polymer (A-2) may be collectively referred to as “polymer (A)”.

  The substituent R of the vinyl compound (I) is a secondary alkyl group, a tertiary alkyl group, or an alicyclic hydrocarbon group. Specific examples of the vinyl compound (I) include vinylcyclohexane.

  The polymer (A-1) may further contain a structural unit derived from a linear α-olefin having 4 to 20 carbon atoms.

  The polymer (A-1) may be further copolymerized with a monomer capable of addition polymerization. Here, the addition-polymerizable monomer is a monomer other than ethylene, propylene, a linear α-olefin having 4 to 20 carbon atoms, and the vinyl compound (I), and ethylene, propylene, having 4 to 20 carbon atoms. It is a monomer that can undergo addition polymerization with a linear α-olefin and vinyl compound (I), and the carbon number of the monomer is usually about 3 to 20.

  Examples of the method for producing the polymer (A-1) include a method for producing the polymer (A-1) in the presence of a catalyst using a transition metal compound having a group having an indenyl anion skeleton or a crosslinked cyclopentadiene anion skeleton, and the like. Is mentioned. Among these, the production method according to the methods described in JP-A No. 2003-82028, JP-A No. 2003-160621 and JP-A No. 2000-128932 is preferable.

  The molecular weight distribution (Mw / Mn = [weight average molecular weight] / [number average molecular weight]) of the polymer (A-1) is usually about 1.5 to 10, preferably about 1.5 to 7, especially Preferably it is about 1.5-5. From the viewpoint of mechanical strength, the weight average molecular weight (Mw) of the polymer (A-1) is usually about 5,000 to 1,000,000, preferably about 10,000 to 500,000. Especially preferably, it is about 15,000 to 400,000. The molecular weight distribution of the polymer (A-1) can be determined using gel permeation chromatograph (GPC) according to the method specifically described in the examples described later.

  The melt flow rate (MFR) of the polymer (A-1) measured under conditions of 190 ° C. and 2.16 kgf using a melt indexer (L217-E14011, manufactured by Techno Seven Co.) in accordance with JIS K 7210. The value of is usually 130 to 300 g / 10 minutes, preferably 130 to 220 g / 10 minutes, from the viewpoint of dispersibility.

  The polymer (A-2) is a polymer obtained by graft polymerization of an α, β-unsaturated carboxylic acid anhydride to the polymer (A-1) thus obtained. As the α, β-unsaturated carboxylic acid anhydride, maleic anhydride is preferable.

Examples of the method for producing the polymer (A-2) include a method in which the polymer (A-1) is melted, and then α, β-unsaturated carboxylic acid anhydride is added and graft polymerization is performed. Examples thereof include a method in which a polymer is dissolved in a solvent such as toluene and xylene, and then α, β-unsaturated carboxylic acid anhydride is added to cause graft polymerization.
After the polymer (A-1) is melted, the α, β-unsaturated carboxylic acid anhydride is added and graft polymerization is performed by melt-kneading using an extruder, so that the resins or the resin and the solid can be solidified. Alternatively, it is preferable because various known methods for mixing liquid additives can be employed. More preferable examples include a method in which all or some of the components are combined and mixed separately with a Henschel mixer, a ribbon blender, a blender or the like to form a uniform mixture, and then the mixture is melt-kneaded. it can.
As the melt-kneading means, conventionally known kneading means such as a Banbury mixer, a plast mill, a Brabender plastograph, a uniaxial or biaxial extruder can be widely employed. Particularly preferable is an olefin copolymer, unsaturated carboxylic acid, radical initiator, which is sufficiently premixed in advance using a single-screw or twin-screw extruder from the viewpoint that continuous production is possible and productivity is improved. A method is recommended in which kneading is carried out by feeding from the feed port of the extruder.
The temperature of the portion where the melt kneading of the extruder is performed (for example, the cylinder temperature in the case of an extruder) is usually 50 to 300 ° C, preferably 80 to 270 ° C. The temperature of the portion of the extruder where the melt kneading is performed is preferably set so that the melt kneading is divided into two stages, the first half and the second half, and the temperature in the second half is higher than the first half. The melt kneading time is usually 0.1 to 30 minutes, particularly preferably 0.1 to 5 minutes.

  In order to graft polymerize the α, β-unsaturated carboxylic acid anhydride to the polymer (A-1), the polymerization is usually carried out in the presence of a radical initiator. The addition amount of the radical initiator is 0.01 to 10 parts by weight, preferably 0.01 to 1 part by weight with respect to 100 parts by weight of the polymer (A-1). The radical initiator is usually an organic peroxide, preferably an organic peroxide having a decomposition temperature of 50 to 210 ° C. with a half-life of 1 minute. These organic peroxides preferably have an action of extracting protons from the polymer (A-1) after generating radicals by decomposition.

  Examples of the organic peroxide having a decomposition temperature of 50 to 210 ° C. with a half-life of 1 minute include 1,3-bis (t-butylperoxyisopropyl) benzene. The addition amount of the organic peroxide is 0.01 to 20 parts by weight, preferably 0.05 to 10 parts by weight with respect to 100 parts by weight of the polymer (A-1).

  The structural unit derived from the α, β-unsaturated carboxylic acid anhydride contained in the polymer (A-2) thus obtained was a ring-opened one even if the acid anhydride group remained closed. The ring-closed one and the ring-opened one may be contained.

  Examples of the molecular weight distribution (Mw / Mn) of the polymer (A-2) in the aqueous emulsion of the present invention include 1.5 to 10 and the like. Preferably 1.5-7 grade | etc., More preferably, 1.5-5 grade | etc., Is mentioned. The molecular weight distribution of the polymer (A-2) can be measured in the same manner as the molecular weight distribution of the polymer (A-1).

  The melt flow rate (MFR) of the polymer (A-2) measured under the conditions of 190 ° C. and 2.16 kgf using a melt indexer (L217-E14011, manufactured by Techno Seven Co.) in accordance with JIS K 7210. From the viewpoint of dispersibility, the value of is preferably from 130 to 300 g / 10 min, and particularly preferably from 130 to 200 g / 10 min.

  In the method of the present invention, examples of the emulsifier suitable for emulsifying the thermoplastic resin described above include, for example, a structural unit derived from an α, β-unsaturated carboxylic acid and a structural unit derived from a (meth) acrylic acid ester. And water-soluble acrylic resins, polyoxyethylene polyoxypropylene block copolymers, and polyoxyethylene alkyl ethers. Two or more kinds of emulsifiers may be used in combination.

In the process of the present invention, suitable emulsifiers for emulsifying the above-mentioned thermoplastic resin include in particular the following:
a structural unit derived from an α, β-unsaturated carboxylic acid (1);
An α, β-unsaturated carboxylic acid ester (2) (hereinafter referred to as “α, β”) containing a C 1-10 alkyl group having a hydroxyl group bonded to a methylene group or a methine group and an α, β-unsaturated carboxylic acid. -Acrylic resin (B) containing a structural unit derived from an unsaturated carboxylic acid ester (2) ".

  Examples of “α, β-unsaturated carboxylic acid (1)” include acrylic acid and methacrylic acid.

  Examples of the “α, β-unsaturated carboxylic acid ester (2)” include 2-hydroxyethyl methacrylate.

  The acrylic resin (B) is necessary in addition to “structural unit derived from α, β-unsaturated carboxylic acid (1)” and “structural unit derived from α, β-unsaturated carboxylic acid ester (2)”. According to the above, “a structural unit derived from an α, β-unsaturated carboxylic acid ester containing an alkyl group having 1 to 20 carbon atoms and an α, β-unsaturated carboxylic acid”, “1 to 1 carbon atoms having an amino group” A structural unit derived from an α, β-unsaturated carboxylic acid ester comprising 10 alkyl groups and an α, β-unsaturated carboxylic acid ”,“ an alkyl group having 1 to 10 carbon atoms having a carboxy group (—COOH) ”, and A structural unit derived from an α, β-unsaturated carboxylic acid ester including an α, β-unsaturated carboxylic acid ”may be contained.

  Examples of the “α, β-unsaturated carboxylic acid ester containing an alkyl group having 1 to 20 carbon atoms and an α, β-unsaturated carboxylic acid” include ethyl acrylate and lauryl methacrylate.

  Examples of the “α, β-unsaturated carboxylic acid ester containing an amino group having 1 to 10 carbon atoms and an α, β-unsaturated carboxylic acid” include N, N-dimethylaminoethyl methacrylate and the like. Is mentioned.

  Examples of the “α, β-unsaturated carboxylic acid ester containing a C 1-10 alkyl group having a carboxy group and an α, β-unsaturated carboxylic acid” include, for example, 2-acryloyloxyethyl succinic acid and the like. Can be mentioned.

  The structural unit derived from these α, β-unsaturated carboxylic acid esters contained in the acrylic resin (B) as necessary is a structural unit derived from a plurality of different α, β-unsaturated carboxylic acid esters. It may be.

  As a manufacturing method of an acrylic resin (B), the method of manufacturing by carrying out addition polymerization of the said monomer mixture is mentioned, for example. Specifically, for example, alcohol such as isopropyl alcohol or water is used as a solvent, and a part or all of the monomer is mixed in the solvent, and usually 70 ° C to 100 ° C, preferably 75 ° C to 95 ° C, particularly preferably. Is a method in which a polymerization initiator such as a radical initiator and the remaining monomers are mixed at 75 ° C. to 85 ° C., and usually stirred for about 1 to 24 hours. In order to control the reaction, the polymerization initiator and the remaining monomers may be dissolved in an organic solvent and then added.

  Here, examples of the polymerization initiator include 2,2'-azobisisobutyronitrile. The amount of the polymerization initiator used is 0.01 to 5 parts by weight, preferably 0.2 to 3 parts by weight, based on 100 parts by weight of the monomer mixture.

When the acrylic resin (B) is used as an emulsifier for emulsifying the thermoplastic resin, the obtained aqueous emulsion preferably has a degree of neutralization of NH ₃ of, for example, 50 to 300, more preferably 100 to 200. Here, the degree of neutralization of NH ₃ is the ratio of the number of moles of ammonia contained in the aqueous emulsion to the total number of moles of structural units derived from the monomer having an anionic group contained in the acrylic resin (B), that is, [ (Number of moles of ammonia) / (total number of moles of anionic monomer) × 100 (%)]
Means.

(Emulsification process)
The emulsification step of emulsifying the resin in water to obtain an emulsion is, for example,
A method of melt-kneading a resin, an emulsifier and water;
A method comprising a heating step of heating a resin, a mixing step of mixing an emulsifier with the resin heated in the heating step, and a dispersion step of dispersing water in the mixture obtained in the mixing step;
A method comprising a step of heating and kneading a resin and an emulsifier, and a step of dispersing the kneaded product obtained in the step in water;
A dissolution step for dissolving the resin in an organic solvent such as toluene, a mixing step for mixing the lysate obtained in the dissolution step with an emulsifier, and mixing the water obtained by mixing the mixture obtained in the mixing step with water. And a removing step of removing the organic solvent from the dispersion obtained in the dispersing step. In addition to the mechanical emulsification method as described above, the emulsification step may be performed by a chemical emulsification method such as self-emulsification. Above all,
Method for melt-kneading resin, emulsifier and water, heating step for heating resin, mixing step for mixing emulsifier with heated resin obtained in said heating step, and mixture obtained in said mixing step with water A method having a dispersion step of dispersing is preferable.

  As an apparatus used in the step of melt-kneading resin, emulsifier and water, for example, a multi-screw such as a twin screw extruder, Labo Plast Mill (Toyo Seiki Seisakusho), Labo Plast Mill Micro (Toyo Seiki Seisakusho) Equipment having barrels (cylinders) such as extruders, homogenizers, TK filmics (Primics Co., Ltd.), such as stirring tanks, chemical stirrers, vortex mixers, flow jet mixers, colloid mills, ultrasonic generators, high pressure homogenizers Dispersion-kun (Fujikin Co., Ltd.), static mixers, micro mixers, and other devices that do not have a barrel (cylinder).

As a shear rate of the apparatus which has a barrel, it is about 200-100000 second- ¹ normally, Preferably it is about 1000-2500 second- ¹ . Here, the shear rate is a numerical value obtained by dividing the peripheral speed [mm / sec] of the outermost peripheral part of the screw element by the clearance [mm] between the screw and the barrel.

As a method of melt-kneading the resin, emulsifier and water, for example, the resin is continuously supplied from the hopper or supply port of the twin-screw extruder, heated and melt-kneaded, and further the compression zone and metering zone of this extruder. Alternatively, the emulsifier is pressurized and supplied from at least one supply port provided in the degassing zone, and the resin is kneaded with a screw, and then water is supplied from at least one supply port provided in the compression zone of the extruder. The method of extruding and producing an emulsion continuously from a die by feeding is used.
As a method comprising a heating step of heating a resin, a mixing step of mixing an emulsifier with the heated resin obtained in the heating step, and a dispersion step of dispersing water in the mixture obtained in the mixing step. For example, after heating the cylinder of the kneader, the resin is put into the cylinder, the heating process is performed to melt while rotating, the emulsifier is then added, the mixing process of rotating is performed, and the resulting mixture is For example, a method of obtaining an emulsion by putting it in warm water and dispersing it.

  As a method comprising a heating step of heating a resin, a mixing step of mixing an emulsifier with the heated resin obtained in the heating step, and a dispersion step of dispersing water in the mixture obtained in the mixing step. A method using a multi-screw extruder is preferred. More specifically, first, a heating process in which a resin is supplied from a hopper of a multi-screw extruder having two or more screws in a casing, followed by heating and melt-kneading, then, a compression zone and / or metering of the extruder. Examples thereof include a method of producing an emulsion through a mixing step of dispersing in water while kneading with an emulsifier supplied from at least one liquid supply port provided in the zone.

  The coarse particle diameter by the grind gauge measurement of the dispersoid in the emulsion obtained by an emulsification process is 30-200 micrometers normally.

  In the emulsion obtained by the method of the present invention, a dispersoid containing a resin and an emulsifier is dispersed in water as a dispersion medium.

  The emulsion obtained by the method of the present invention is preferably one in which the dispersoid comprising the polymer (A) and the acrylic resin (B) is dispersed in water as a dispersion medium. The volume-based median diameter of the dispersoid is, for example, 0.01 to 3 μm, preferably 0.1 to 2.5 μm, and more preferably 0.3 to 1.5 μm. When the volume-based median diameter is 0.01 μm or more, it is preferable from the viewpoint of easy production, and when it is 3 μm or less, adhesiveness tends to be improved. Here, the volume-based median diameter is a particle diameter corresponding to 50% of the cumulative particle diameter distribution on a volume basis.

The content of the emulsifier in the emulsion obtained by the method of the present invention is, for example, 1 to 30 parts by weight, preferably 2 to 10 parts by weight with respect to 100 parts by weight of the resin.
The content of the resin in the emulsion obtained by the method of the present invention is, for example, 10 to 70 parts by weight, preferably 30 to 60 parts by weight, and more preferably 40 to 100 parts by weight with respect to 100 parts by weight of the emulsion. 60 parts by weight.
The water content in the emulsion obtained by the method of the present invention is, for example, 10 to 90 parts by weight, preferably 30 to 70 parts by weight, and more preferably 40 to 100 parts by weight with respect to 100 parts by weight of the emulsion. 60 parts by weight.

  The emulsion of the present invention may contain two or more kinds of resins, such as fillers such as clay, kaolin, talc and calcium carbonate, preservatives, rust preventives, antifoaming agents, foaming agents, and polyacrylic. Thickeners such as acids, polyethers, methylcellulose, carboxymethylcellulose, polyvinyl alcohol, starch, viscosity modifiers, flame retardants, pigments such as titanium oxide, dibasic acid dimethyl succinate, high boiling point solvents such as dimethyl adipate, A plasticizer or the like may further be contained.

(Crushing process)
Aggregated grains are pulverized by applying mechanical shearing force, impact force or frictional force to the obtained emulsion. The pulverization method is not particularly limited, and examples thereof include a bead type such as a pot mill, a bead mill and a sand grinder, a type using a shearing force such as a colloid mill, and a high pressure collision type such as a jet mill. When pulverization is performed using a bead mill, the bead material is preferably zirconia, the bead diameter is 0.5 mmφ, the bead amount is 1.6 kg, the peripheral speed is 10 m / s, the pulverization time is 1 hour, and the amount of emulsion. Is 0.8 kg.

  It is preferable that the coarse particle diameter by the grind gauge measurement of the dispersoid in the aqueous | water-based emulsion obtained at a grinding | pulverization process is 1-30 micrometers.

  The cured product obtained by drying water from the aqueous emulsion obtained by the method of the present invention tends to give a smooth surface. Therefore, when the aqueous emulsion obtained by the method of the present invention is applied to a substrate as a paint, the workability tends to be excellent, and the appearance of the resulting laminate tends to be excellent.

The aqueous emulsion obtained by the method of the present invention is coated (coated) on a substrate, and then dried to form a coating film (coating film) of the aqueous emulsion on the substrate.
The coating film can be used, for example, for paints, primers, base materials, adhesives and the like.

  The “base material” in the present invention means an article having an arbitrary shape intended to be coated with the aqueous emulsion of the present invention, such as an adherend and an adherent layer. Examples of the substrate in the present invention include wood-based materials such as wood, plywood, MDF, particle board, and fiber board; paper-based materials such as wallpaper and wrapping paper: cellulosic materials such as cotton, linen, and rayon; polyethylene ( Polyolefins whose main component is a structural unit derived from ethylene (hereinafter the same), polypropylene (polyolefins whose main component is a structural unit derived from propylene, the same applies hereinafter), polyolefins such as polystyrene, polycarbonate, acrylonitrile / butadiene / styrene copolymer Combined (ABS resin), (meth) acrylic resin, plastic materials such as polyester, polyether, polyvinyl chloride, polyurethane, urethane foam; ceramic materials such as glass and ceramics; metal materials such as iron, stainless steel, copper, and aluminum Can be mentioned.

  Such a substrate may be a composite material composed of a plurality of materials. Further, an inorganic filler such as talc, silica, activated carbon, or the like, and a kneaded molded product of carbon fiber or the like and a plastic material may be used.

  As the substrate, among them, polypropylene, polystyrene, polycarbonate, acrylonitrile / butadiene / styrene copolymer (ABS resin), polyethylene terephthalate, polyvinyl chloride, (meth) acrylic resin, glass, aluminum, polyurethane and the like are preferable. Polypropylene, polyvinyl chloride, glass, aluminum and polyurethane are preferred.

When one of the substrates is a water-absorbing substrate such as a wood-based material, a paper-based material, or a cellulosic material, the aqueous emulsion of the present invention can be applied as it is and bonded to another substrate. . That is, after coating an aqueous emulsion on a water-absorbing substrate, if another substrate (which may be water-absorbing or non-water-absorbing) is laminated on the layer derived from the aqueous emulsion, the water content in the aqueous emulsion is The coating film which is absorbed by the water-absorbing substrate and is derived from the aqueous emulsion becomes an adhesive layer, and a laminate having the water-absorbing substrate / the coating film / substrate derived from the aqueous emulsion of the present invention can be obtained.
When the base material is non-water-absorbing, such as polyolefin, after coating the aqueous emulsion on one side of one base material and heating to form a coating film derived from the aqueous emulsion of the present invention, the other base What is necessary is just to bond a material and to heat and to make it adhere | attach further.
Examples of the heating temperature when forming a coating film derived from an aqueous emulsion and the heating temperature after bonding the other substrate and the coating film derived from an aqueous emulsion include 60 to 200 ° C. Can do.

  Accordingly, the present invention also provides a base material comprising at least one material selected from the group consisting of woody materials, cellulosic materials, plastic materials, ceramic materials and metal materials, and a coating derived from the aqueous emulsion of the present invention. A laminate including a film is provided.

  Furthermore, the present invention applies the aqueous emulsion of the present invention to a substrate containing at least one material selected from the group consisting of woody materials, cellulosic materials, plastic materials, ceramic materials and metal materials, The first step of obtaining a coated product comprising the substrate and the layer containing the aqueous emulsion, and the coated product obtained in the first step are dried to derive from the substrate and the aqueous emulsion of the invention. The manufacturing method of a laminated body including the 2nd process of obtaining the laminated body containing a coating film is provided.

  The present invention will be described in more detail with reference to the following examples, but the present invention is not limited thereto. In the examples, parts and% mean weight basis unless otherwise specified.

<Molecular weight and molecular weight distribution>
The molecular weight of the resin was obtained under the following conditions after calibrating with polystyrene (molecular weight 688 to 400,000) standard substance using gel permeation chromatograph (GPC). The molecular weight distribution was evaluated by the ratio (Mw / Mn) between the weight average molecular weight (hereinafter referred to as Mw) and the number average molecular weight (hereinafter referred to as Mn).
Model Waters 150-C
Column shodex packed column A-80M
Measurement temperature 140 ℃
Measurement solvent Orthodichlorobenzene measurement concentration 1mg / ml

<Content of vinylcyclohexane unit>
The content of the vinylcyclohexane unit in the copolymer was determined by the following ¹³ C-NMR apparatus.
¹³ C-NMR apparatus: DRX600 manufactured by BRUKER
Measuring solvent: orthodichlorobenzene and orthodichlorobenzene-d4
4: 1 (volume ratio) liquid mixture Measurement temperature: 135 ° C

<Graft amount>
The graft amount of maleic anhydride of the polymer (A-2) was measured by the following procedure. 1.0 g of sample was dissolved in 20 ml of xylene, and the sample solution was added dropwise to 300 ml of methanol with stirring to reprecipitate and collect the sample. Thereafter, the collected sample was vacuum dried (80 ° C., 8 hours), and a film having a thickness of 100 μm was produced by hot pressing. The infrared absorption spectrum of the obtained film was measured, and the amount of maleic anhydride grafted was quantified from the absorption near 1780 cm ⁻¹ .

<Melt flow rate>
The melt flow rate (MFR) of the resin was measured under conditions of 190 ° C. and 2.16 kgf using a melt indexer (L217-E14011, manufactured by Techno Seven Co.) in accordance with JIS K 7210.

<Solid content>
The measurement of solid content was performed by the measuring method according to JIS K-6828.

<NH ₃ neutralization degree>
The degree of neutralization of NH ₃ of the acrylic resin (B) is used for the total number of moles of acrylic acid (AA) ([AA]) and methacrylic acid (MAA) contained in the acrylic resin (B). Of the number of moles of ammonia ([NH ₃ ]),
[NH ₃ ] / ([AA] + [MAA]) × 100 (%)
Calculated as

<Average particle size>
It is a volume-based median diameter obtained using a laser diffraction particle size distribution analyzer LA-910 (manufactured by Horiba, Ltd.) with a particle refractive index of 1.50-0.20i.

<Coarse particle size>
A water-based emulsion is poured into a deep position of a groove of a Gardner grindometer (standard JIS K5600, range 0 to 100 μm), and the scraper is pushed from the deep position of the groove to a shallow direction, and is moved at an even speed. I read the scale that began to appear more than one. This measurement was repeated three times, and the average value was defined as the coarse particle diameter.

[Example 1]
(Manufacture of resin)
386 parts of vinylcyclohexane (hereinafter sometimes referred to as VCH) and 3640 parts of toluene were charged into a SUS reactor substituted with argon. After raising the temperature to 50 ° C., ethylene was charged while being pressurized at 0.6 MPa. 10 parts of a toluene solution of triisobutylaluminum (TIBA) [TIBA concentration 20% manufactured by Tosoh Akzo Co., Ltd.] was charged, followed by diethylsilyl (tetramethylcyclopentadienyl) (3-tert-butyl-5-methyl- 2-phenoxy) titanium dichloride 0.001 part dissolved in dehydrated toluene 87 parts and dimethylanilinium tetrakis (pentafluorophenyl) borate 0.03 part dissolved in dehydrated toluene 122 parts were added and stirred for 2 hours did. The obtained reaction solution was poured into about 10,000 parts of acetone, and the precipitated white solid was collected by filtration. The solid was washed with acetone and then dried under reduced pressure. As a result, 300 parts of an olefin copolymer (A-1) was obtained. The copolymer has a viscosity (η) of 0.48 dl / g, Mn of 15,600, a molecular weight distribution (Mw / Mn) of 2.0, a melting point (Tm) of 57 ° C., and a glass transition point (Tg) of − At 28 ° C., the content of VCH units in the copolymer was 13 mol%.

  After 100 parts of the resulting polymer (A-1) is added 0.4 parts of maleic anhydride and 0.04 parts of 1,3-bis (t-butylperoxyisopropyl) benzene and sufficiently premixed. It supplied from the supply port of the twin screw extruder and melted and kneaded to obtain a polymer (A-2). The temperature of the part of the extruder where the melt kneading was performed was divided into two stages, the first half and the latter half, and the melt kneading was performed at a temperature setting of 180 ° C. in the first half and 260 ° C. in the second half. The maleic acid graft amount of the polymer (A-2) was 0.2%. The MFR of the polymer (A-2) was 180 g / 10 min (190 ° C., load: 2.16 kgf).

(Manufacture of emulsifiers)
As the emulsifier monomer, the monomers listed in Table 1 were used.

"AA" 7.5 parts (10.9 mole ratio), "MAA" 22.5 parts (27.4 mole ratio), "HEA" 29.5 parts (26.6 mole ratio), "EA" 29. 5 parts (30.8 molar ratio) and 11 parts of “SLMA” (4.4 molar ratio) were mixed at 10 to 30 ° C. to obtain 100 parts of a monomer mixture. Here, the molar ratio represents the number of moles when the total number of moles of the monomers is 100.
To the reactor, 150 parts of isopropyl alcohol (hereinafter sometimes referred to as IPA) and the monomer mixture were charged, and after replacing the reactor with nitrogen, the internal temperature was adjusted to 50 ° C. with stirring. 0.6 part of 2,2′-azobisisobutyronitrile was added as a polymerization initiator, and the temperature was raised to 80 ° C., followed by stirring at the same temperature for 2 hours. Next, 0.3 part of the polymerization initiator was added at the same temperature, and the mixture was further stirred at the same temperature for 1 hour. Subsequently, the temperature of the resulting reaction solution was raised to a boiling point to distill off the IPA, and after distilling, the internal temperature was lowered to 50 ° C., and then 29 parts (48 molar ratio) of 28% aqueous ammonia solution was mixed. Thereafter, a viscous emulsifier was obtained (yield 90%, solid content 50%). Table 2 summarizes the types and amounts of monomers used, the amount of aqueous ammonia, the degree of neutralization of NH ₃ , the amount of solids, and the yield.

(Emulsification process)
After setting the cylinder temperature of the same direction rotation meshing type twin screw extruder (Technovel: KZW15TW-15 / 45MG-NH (-1100), L / D = 45) to 110 ° C., the hopper of the extruder From the above, 100 parts of polymer (A-2), which is a thermoplastic resin, was continuously supplied at a screw rotation speed of 500 rpm to heat the polymer (A-2).
From the supply port provided in the vent part of the extruder, 10 parts of emulsifier (solid content) is continuously supplied while being pressurized with a gear pump, and the polymer (A-2) and the emulsifier are continuously extruded and mixed. Furthermore, 100 parts of ion-exchanged water was added while being pressurized with a plunger pump from another supply port provided in the vent part to obtain a milky white emulsion. The average particle size of the dispersoid in the obtained emulsion was 0.7 μm, and the coarse particle size was 54 μm.

(Crushing process)
0.8 kg of the emulsion obtained in the above production example is put into a supply tank, and circulated and fed into a continuous circulation bead mill (Shinmaru Enterprises: Dino Mill KDL 0.6) vessel using a peristaltic pump. Started. Further, 1.6 kg of 0.5 mmφ zirconia beads were put into the vessel and stirred at a peripheral speed of 10 m / s for 1 hour. The obtained aqueous emulsion had a dispersoid coarse particle size of 25 μm.

  The aqueous emulsion produced by the method of the present invention can give a thin film having an excellent appearance.

Claims (16)

An emulsification step of emulsifying the resin in water to obtain an emulsion;
A method for producing an aqueous emulsion, comprising: adding a mechanical shearing force, impact force or frictional force to the emulsion obtained in the previous step to pulverize the aggregated particles to obtain an aqueous emulsion.   The method according to claim 1, wherein the coarse particle size of the dispersoid of the emulsion obtained in the emulsification step is 30 to 200 μm.   The method according to claim 1 or 2, wherein the coarse particle size of the dispersoid of the aqueous emulsion obtained in the pulverization step is 1 to 30 µm.   The method according to any one of claims 1 to 3, wherein the agglomerated particles are pulverized using at least one apparatus selected from a bead mill, a colloid mill, and a jet mill.   The method according to claim 1, wherein the resin is a thermoplastic resin.   The method according to claim 5, wherein the thermoplastic resin comprises a thermoplastic polymer containing structural units derived from ethylene and / or propylene. An α, β-unsaturated carboxylic acid anhydride is graft polymerized to an olefin copolymer in which the thermoplastic resin contains a structural unit derived from ethylene and / or propylene and a structural unit derived from the following vinyl compound (I). The method according to claim 6, comprising a polymer.
_{CH 2 = CH-R (I} )
(In the formula, R of the vinyl compound (I) represents a secondary alkyl group, a tertiary alkyl group, or an alicyclic carbocyclic group.)   The method according to claim 7, wherein the structural unit derived from the vinyl compound (I) comprises a structural unit derived from vinylcyclohexane.   The method of any one of Claims 5-8 that the melt flow rate (190 degreeC, 2.16kgf) of a thermoplastic resin is 130 g / 10min or more and 300 g / 10min or less. The emulsifier used to emulsify the resin is
a water-soluble acrylic resin containing a structural unit derived from an α, β-unsaturated carboxylic acid and a structural unit derived from a (meth) acrylic acid ester,
The method according to any one of claims 5 to 9, which is at least one emulsifier selected from the group consisting of a polyoxyethylene polyoxypropylene block copolymer and a polyoxyethylene alkyl ether.   The method according to any one of claims 1 to 10, wherein the volume-based median diameter of the dispersoid in the emulsion before pulverization is 0.01 µm to 3 µm.   The aqueous emulsion obtained by the method in any one of Claims 1-11.   A method for forming a coating film on a substrate, wherein the aqueous emulsion according to claim 12 is coated on a substrate and dried.   A coating film obtained by coating the aqueous emulsion according to claim 12 and drying it.   A base material comprising at least one material selected from the group consisting of a wood material, a cellulosic material, a plastic material, a ceramic material, and a metal material, and the coating film according to claim 14. A laminate characterized by the following. Applying the aqueous emulsion according to claim 12 to a substrate comprising at least one material selected from the group consisting of a woody material, a cellulosic material, a plastic material, a ceramic material and a metal material, A first step of obtaining a coated product comprising a substrate and a layer comprising the aqueous emulsion;
A second step of drying the coated product obtained in the first step to obtain a laminate comprising the base material and a coating film derived from the aqueous emulsion. Production method.