JPH11193340A - Aqueous dispersion and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an aqueous dispersion which forms a coating film excellent in adhesion, gas barrier properties, corrosion resistance, etc. SOLUTION: There is provided an aqueous dispersion comprising 100 pts.wt. ethylene/vinyl alcohol copolymer (A), 1-400 pts.wt. mixture (B) of a thermoplastic resin containing polymer-chain-bonded carboxylate groups in a concentration of 0.01-10 mol equivalents (in terms of the -COO- groups),per gram of the polymer and having a limiting viscosity [η] of 0.15 dl/g or above with a thermoplastic resin having a limiting viscosity [η] of below 0.15 dl/g, 0.1-40 pts.wt. anionic or nonionic surfactant (C), and water (D), wherein part or all of the -COO- groups bonded to the polymer chain of the thermoplastic polymer (B) are in the form of a carboxylate, the water content is 5-90 wt.%, and the resin solids are present in the form of dispersed microparticles. Thus, it is possible to obtain an aqueous dispersion containing an ethylene/vinyl alcohol copolymer in high yields. A film formed from this dispersion possesses the excellent properties (gas barrier properties, etc.), inherent in the ethylene/vinyl alcohol copolymer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aqueous dispersion containing an ethylene-vinyl alcohol copolymer, and more particularly to an aqueous dispersion which forms a film having excellent adhesion, gas barrier properties, corrosion resistance and the like.

[0002]

2. Description of the Related Art Ethylene-vinyl alcohol copolymer is known to be useful as a coating film on surfaces of plastic molded products, metals, papers, woods, etc. because of its excellent gas barrier properties against oxygen and chemical resistance. Have been. In general, as a method of forming a coating film, a method of melt extrusion, injection molding, or a method of laminating an ethylene-vinyl alcohol copolymer film is used. But,
In these methods, since the film thickness is relatively thick, the demand for ethylene-vinyl alcohol copolymer solutions and dispersions is increasing. There is a strong demand for controlling the impact.

The present inventors have described a process for producing an aqueous dispersion of an ethylene-vinyl alcohol copolymer in Japanese Patent Publication No.
As reported at -8933, the yield was not yet sufficient. Further, a method has been proposed in which an ethylene-vinyl alcohol copolymer is modified to obtain an aqueous dispersion (Japanese Patent Application Laid-Open No. 54-101844), but the property of the ethylene-vinyl alcohol copolymer is impaired by the modification. was there.

[0004]

DISCLOSURE OF THE INVENTION The present invention provides an aqueous dispersion containing an ethylene-vinyl alcohol copolymer in high yield, and a film formed by the aqueous dispersion has an ethylene-vinyl alcohol copolymer. An aqueous dispersion characterized by having the properties of a polymer, and a method for producing the same.

[0005]

In order to solve the above-mentioned problems, the present invention provides (A) 100 parts by weight of an ethylene-vinyl alcohol copolymer, and (B) a polymer having a -COO- group bonded to a polymer chain. A thermoplastic polymer having an intrinsic viscosity [η] of 0.15 dl / g or more and a intrinsic viscosity [η] of 0.15 dl, which is contained at a concentration of 0.01 to 10 millimolar equivalents in terms of —COO— groups per gram.
/ G of thermoplastic polymer less than 1/400 parts by weight (C) anionic or nonionic surfactant 0.1 to
40 parts by weight and (D) water, and (B) a part or all of the -COO- group bonded to the polymer chain of the thermoplastic polymer is in a carboxylate state, and the water content is It is an object of the present invention to provide an aqueous dispersion characterized in that the resin solid content is present as finely dispersed particles at 5 to 90% by weight and a method for producing the same. Hereinafter, the present invention will be described in detail.

The ethylene-vinyl alcohol copolymer (A), which is one of the components constituting the aqueous dispersion of the present invention, comprises:
Ethylene content is 10-70 mol%, melting point is 150-1
90 ° C., molecular weight is 1-50 g / 10 min.
(ASTM D1238, 190 ° C., 2160 g).

The thermoplastic polymer (B) which is one of the components constituting the aqueous dispersion of the present invention is an α-olefin (co)
The polymer or the α-olefin constituting the polymer has a monomer having a neutralized or non-neutralized carboxylic acid group, or has a saponified or unsaponified carboxylic acid ester group The monomer is introduced by means such as graft copolymerization, block copolymerization, random copolymerization, etc., or in some cases, a neutralization reaction or a saponification reaction is carried out with a basic substance to thereby form a polymer chain of the polymer. This is adjusted so that part or all of the -COO- group bonded to is a carboxylate. At this time, the polymer may be a partially neutralized product or a partially saponified product in which a carboxylic acid group or carboxylic acid ester group that has not been neutralized or saponified is present. The thermoplastic polymer (B) is preferably water-insoluble and non-water-swellable from the viewpoint of improving emulsifiability and obtaining an aqueous dispersion with a good yield.

When the thermoplastic polymer (B) is obtained by post-neutralization or post-saponification, the polymer as a raw material is, for example, an α-olefin and an ethylenically unsaturated carboxylic acid, an anhydride thereof or an ester thereof. Or an α-olefin (co) polymer graft-polymerized with an ethylenically unsaturated carboxylic acid, an anhydride thereof or an unsaturated ester thereof.

The ethylenically unsaturated carboxylic acids include
(Meth) acrylic acid, maleic acid, fumaric acid, tetrahydrophthalic acid, itaconic acid, citraconic acid, crotonic acid and isocrotonic acid, and as anhydrides thereof, nadic acid (endosis-bicyclo [2,2,1] hept-5) Examples of the unsaturated carboxylic acid ester such as -ene-2,3-dicarboxylic acid), maleic anhydride and citraconic anhydride include the monoesters and diesters of the above-mentioned unsaturated carboxylic acid methyl, ethyl and propyl. These monomers can be used alone or in combination.

As a copolymer of an α-olefin and an ethylenically unsaturated carboxylic acid, an anhydride thereof or an ester thereof, an ethylene- (meth) acrylic acid copolymer is preferably used.

As a method of graft-polymerizing an ethylenically unsaturated carboxylic acid, an anhydride thereof or an unsaturated ester thereof to an α-olefin (co) polymer, various methods known in the art can be mentioned. For example, there is a method in which the α-olefin (co) polymer is melted and a graft monomer is added for graft polymerization, or a method in which the α-olefin (co) polymer is dissolved in a solvent and the graft monomer is added for graft polymerization. In any case, it is preferable to carry out the reaction in the presence of a radical reaction initiator in order to efficiently graft the graft monomer.

[0012] The grafting reaction is usually carried out at a temperature of 60 to 350 ° C. The usage ratio of the radical initiator is usually 0.01 to 1 with respect to 100 parts by weight of the thermoplastic polymer (B).
The range is 0 parts by weight. Examples of the radical initiator include organic peroxides, organic peresters, and other azo compounds. Among these radical initiators, dicumyl peroxide, di-tert-butyl peroxide,
2,5-dimethyl-2,5-di (tert-butylperoxy) hexyne-3, 2,5-dimethyl-2,5-di (tert-butylperoxy) hexane, 1,4-bis (tert-butylperoxyisopropyl) benzene And the like are preferred.

The amount of the ethylenically unsaturated carboxylic acid, anhydride or ester thereof introduced into the monomer is 0.01-COO-group per gram of the polymer.
It is preferably in the range of 10 to 10 mmol equivalent, particularly 0.1 to 5 mmol equivalent.

The thermoplastic polymer (B) has a molecular weight of 0.005 to 5 dl / g in intrinsic viscosity [η], preferably 0.1 to 5 dl / g.
Those having a range of 01 to 3 dl / g are used. In the present invention, two or more kinds of thermoplastic polymers having different intrinsic viscosities [η] are used. That is, [η] is 0.15 dl / g
The above thermoplastic polymer (E) and the thermoplastic polymer (F) of less than 0.15 dl / g are required at the same time.

The intrinsic viscosity [η] of the thermoplastic polymer (E) is usually 0, 15 dl / g or more and 5 dl / g or less, preferably 0, 15 dl / g or more and 3 dl / g or less. The intrinsic viscosity [η] of F) is usually 0.005 d.
1 / g or more and less than 0.15 dl / g, preferably 0,0
It is 1 dl / g or more and less than 0.15 dl / g. The ratio of the intrinsic viscosities of (E) and (F) is preferably such that (E) / (F) is in the range of 2 to 10. The mixing ratio of (E) and (F) is (E) / (F) = 1/20 to 20/1, preferably 1/10 to 10/1, by weight.

The thermoplastic polymer (B) is used in an amount of 1 to 400 per 100 parts by weight of the ethylene-vinyl alcohol copolymer.
Parts by weight, preferably 5 to 300 parts by weight, more preferably 5 to 250 parts by weight.

Examples of the basic substance used for neutralization and saponification include substances which act as bases in water, such as alkali metals, alkaline earth metals, ammonia and amines, alkali metal oxides, hydroxides, weak bases, and the like. Examples thereof include substances that act as bases in water, such as hydrides, oxides and hydroxides of alkaline earth metals, weak bases, and hydrides, and alkoxides of these metals.

Examples of the alkali metal include sodium, potassium and lithium, and examples of the alkaline earth metal include calcium, strontium and barium. As the amine, for example,
Examples thereof include inorganic amines such as hydroxylamine and hydrazine, methylamine, ethylamine, ethanolamine, and cyclohexylamine.

Examples of the oxides, hydroxides and hydrides of alkali metals and alkaline earth metals include, for example, sodium oxide, sodium peroxide, potassium oxide, potassium peroxide, calcium oxide, strontium oxide, barium oxide, and hydroxide. Examples thereof include sodium, potassium hydroxide, calcium hydroxide, strontium hydroxide, barium hydroxide, sodium hydride, potassium hydride, calcium hydride and the like.

Examples of the weak bases of alkali metals and alkaline earth metals include sodium carbonate, potassium carbonate, sodium hydrogencarbonate, potassium hydrogencarbonate, calcium hydrogencarbonate, sodium acetate, potassium acetate, calcium acetate and the like. .

Examples of the ammonia and amine compounds include ammonium hydroxide and quaternary ammonium compounds such as tetramethylammonium hydroxide and hydrazine hydrate.

As the carboxylate neutralized or saponified with a basic substance, an alkali metal carboxylate such as sodium carboxylate and potassium carboxylate, and ammonium carboxylate are preferable.

As the surfactant (C), an anionic or nonionic surfactant is used. Examples of anionic surfactants include primary higher fatty acid salts and secondary higher fatty acid salts.
Higher fatty acid salts, primary higher alcohol sulfates, secondary higher alcohol sulfates, primary higher alkyl sulfonates, secondary higher alkyl sulfonates, higher alkyl disulfonates, sulfonated higher Fatty acid salt, higher fatty acid sulfate ester salt, higher fatty acid ester sulfonate, higher alcohol ether sulfate sulfonate, higher alcohol ether sulfonate, higher fatty acid amide alkylolated sulfate ester, alkylbenzene sulfonate, alkylphenol Any anionic surfactant such as a sulfonate, an alkyl naphthalene sulfonate, and an alkylbenzimidazole sulfonate may be used. Particularly preferred are higher fatty acids, especially salts of saturated or unsaturated higher fatty acids having 10 to 20 carbon atoms, especially alkali metal salts. More specifically, capric acid, undecanoic acid Unsaturated fatty acids such as lauric acid, myristic acid, palmitic acid, margaric acid, stearic acid, saturated fatty acids such as arachinic acid, lindenic acid, tunic acid, petroselinic acid, oleic acid, linoleic acid, linoleic acid, arachidonic acid, Alternatively, alkali metal salts of these mixtures can be mentioned. As nonionic surfactants,
Polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene fatty acid ester, polyoxyethylene fatty acid amide ether, polyhydric alcohol fatty acid ester, polyoxyethylene polyhydric alcohol fatty acid ester, fatty acid sucrose ester, alkylolamide, Examples thereof include polyoxyalkylene block copolymers. These may be used alone or in combination.

The surfactant (C) is used in an amount of 0.1 to 4 per 100 parts by weight of the ethylene-vinyl alcohol copolymer (A).
It is preferably present in an amount of 0 parts by weight, especially 0.5 to 30 parts by weight.

The aqueous dispersion of the present invention further contains water in the above-mentioned constitution, and the water content is preferably 5 to 90% by weight based on the whole aqueous dispersion. It is preferably 20 to 80% by weight. Further, the average particle size of the dispersed particles of the dispersion of the present invention is usually 0.0
It is 1 to 20 μm, preferably 0.05 to 10 μm.

Next, the manufacturing method will be described. In the present invention, the components (A), (B) and (C) are melt-mixed. In this case, instead of using a thermoplastic polymer (B) having a carboxylate group, a group of a carboxylic acid, anhydride or ester thereof which can be neutralized and / or saponified and bonded to the polymer chain. With -CO per gram of polymer
Using a thermoplastic polymer having a concentration of 0.01 to 10 mmol equivalent in terms of O-group, neutralization and saponification may be performed later with a basic substance, or in place of the anionic surfactant. Alternatively, kneading may be performed using an organic compound that becomes an anionic surfactant by neutralization with a basic substance, and neutralization may be performed later.

In the first step of the production method, the ethylene-vinyl alcohol copolymer (A), the thermoplastic polymer (B) and the surfactant (C) are melt-kneaded. Is higher than the melting point of ethylene-vinyl alcohol, preferably, the melt viscosity is 105 mPa ·
s or higher.

In the second step, water is added to the melt-kneaded material, and the solid phase of the resin is phase-inverted into dispersed particles.
The amount of water to be added is in the range described above. In the second step, when an unneutralized and / or unsaponified thermoplastic polymer (B) is used and / or when an unneutralized organic compound for an anionic surfactant is used, The basic substance necessary to neutralize is added. Suitable examples of basic substances are those already mentioned above, which may be added directly, but are preferably added in the form of an aqueous solution. The first step and the second step described above may be performed sequentially or simultaneously.

The melt-kneading means that can be used in the production method of the present invention may be any known method, and preferred examples include a kneader, a Banbury mixer, and a multi-screw extruder.

The aqueous dispersion thus produced is melted and kneaded by sequentially dropping water, and then the produced aqueous dispersion is cooled naturally or artificially to room temperature. In the production of this dispersion, various auxiliary materials which can be usually used for aqueous dispersions, such as emulsifiers, stabilizers, wetting agents, thickeners, foaming agents, defoamers, coagulants, gelling An agent, an antioxidant, a plasticizer, a filler, a coloring agent, a fragrance, an antiadhesive, a release agent, and the like can be used in combination as needed.

The aqueous dispersion of the present invention comprises paper; pulp; metals such as aluminum, iron and copper; glass; wood; cotton; polyolefins such as polyethylene and polypropylene; polyesters such as polyethylene terephthalate;
It can be applied to various substrates such as plastics such as polystyrene. These substrates may be in any shape, such as fibers, nonwovens, films / sheets, containers, and the like.

The film formed by the aqueous dispersion of the present invention has gas barrier properties, antistatic properties, moisture proof properties, water repellency, thermal adhesion to the above various substrates, printability, thermal transfer properties, friction resistance, and impact resistance. Excellent in nature. Therefore, the aqueous dispersion of the present invention is an adhesive,
It can be used as a paint, a glass fiber treating agent, a coating agent and the like. Specifically, for example, a binder for wallpaper by paper coating; a fiber coating agent; a fiber sizing agent such as nylon and polyester; a glass fiber sizing agent;
Fillers and adhesives for paper and non-woven fabrics; agents for imparting gas barrier properties such as paper, OPP and PET films; thermal adhesives for sterilized paper; rust-preventive paint binders for metal surfaces such as aluminum and steel plates;
Ink and paint anti-wear and anti-slip adjusters; inkjet printer paper and film surface coating agents; and automotive coatings (intermediate and top coats) chipping resistance improvers.

In the present invention, the intrinsic viscosity [η]
Is a value measured at 135 ° C. in a decalin solvent.

Examples have been described below, but the present invention is not limited by the examples. Example 1 Ethylene-vinyl alcohol copolymer (G-110A manufactured by Kuraray Co., Ltd., ethylene content: 47 mol%, melting point: 1)
60 ° C.) as a thermoplastic polymer, an ethylene-methacrylic acid copolymer (Nucrel 1560, manufactured by DuPont-Mitsui Polychemicals Co., Ltd., -COO-group: 1.7)
4 mmol equivalent / g, [η]: 0.2 dl / g)
00g, ethylene-acrylic acid copolymer (Primacol 5933, manufactured by Dow Co., Ltd., -COO- group: 2.97 mm)
ol equivalent / g, [η]: 0.05 dl / g)
g, ethylene-acrylic acid copolymer (Allied AC
-5120, -COO- group: 2.97 mmol equivalent /
g, [η]: 0.06 dl / g), 1000 g of emernon 3299 (nonionic surfactant manufactured by Kao) as a surfactant, and a twin screw extruder (PCM-30L manufactured by Ikegai Iron Works). / D = 20) at a rate of 1500 g / hour, and a 7% solution of potassium hydroxide is continuously supplied at a rate of 650 g / hour from a supply port provided in a vent portion of the extruder. Heating temperature 1
Extruded continuously at 70 ° C. The extruded resin mixture was cooled to 90 ° C. by a jacketed static mixer installed at the extruder opening, and further poured into hot water at 80 ° C. to obtain an aqueous dispersion having a yield of 95% and a solid content of 30%. Obtained. The average particle size of the obtained aqueous dispersion was 7 μm as measured by Microtrac.

Example 2 Ethylene-vinyl alcohol copolymer (G-110A manufactured by Kuraray Co., Ltd., ethylene content: 47 mol%, melting point: 1)
60 ° C.) as a thermoplastic polymer, an ethylene-methacrylic acid copolymer (Nucrel 1560, manufactured by DuPont-Mitsui Polychemicals Ltd., -COO-group: 1.7)
4 mmol equivalent / g, [η]: 0.2 dl / g)
00g, ethylene-acrylic acid copolymer (made by Allied
AC-5120, -COO- group: 2.97 mmol equivalent / g, [η]: 0.06 dl / g), 1000 g of surfactant, and 30 g of emernon 3299 (nonionic surfactant manufactured by Kao) as a surfactant. And supplied from a hopper of a twin screw extruder (PCM-30L / D = 20 manufactured by Ikegai Iron Works) at a rate of 1500 g / hour, and 7% of potassium hydroxide was supplied from a supply port provided in a vent portion of the extruder. The solution was continuously supplied at a rate of 380 g / hour and continuously extruded at a heating temperature of 170 ° C. The extruded resin mixture was cooled to 90 ° C. by a jacketed static mixer installed at the extruder opening, and further poured into warm water of 80 ° C. to obtain an aqueous dispersion having a yield of 87% and a solid concentration of 24%. Obtained. The average particle size of the obtained aqueous dispersion was 1.8 μm as measured by Microtrac.

Comparative Example 1 Ethylene-vinyl alcohol copolymer (manufactured by Kuraray Co., Ltd.)
G-110A, ethylene content: 47 mol%, melting point: 16
3,000 g of ethylene-acrylic acid copolymer (AC-5120 manufactured by Allied, -COO- group: 2.9)
7 mmol equivalent / g, [η]: 0.06 dl / g)
As a surfactant, 18 g of Emarnon 3299 (a nonionic surfactant manufactured by Kao) was mixed with a surfactant, and a twin screw extruder (PCM-30L / D manufactured by Ikegai Iron Works) was used.
The extruder was supplied at a rate of 1500 g / hr from the hopper of 20), and a 7% solution of potassium hydroxide was continuously supplied at a rate of 380 g / hr from a supply port provided at the vent of the extruder. Extruded continuously at ° C. The extruded resin mixture was cooled to 90 ° C. by a jacketed static mixer installed at the extruder opening, and further poured into warm water of 80 ° C. to obtain an aqueous dispersion having a yield of 18% and a solid content of 15%. Obtained. The average particle size of the obtained aqueous dispersion was 5.8 μm as measured by Microtrac.
Met.

Comparative Example 2 Ethylene-methacrylic acid copolymer (Nucrel 1560, manufactured by DuPont-Mitsui Polychemicals Co., Ltd., -COO- group:
1.74 mmol equivalent / g, [η]: 0.2 dl / g)
3,000 g of an ethylene-acrylic acid copolymer (AC-5120 manufactured by Allied, -COO- group: 2.97 mmol)
1 equivalent / g, [η]: 0.06 dl / g), 300 g,
As a surfactant, 9 g of Emarnon 3299 (nonionic surfactant manufactured by Kao) is mixed and supplied at a rate of 1500 g / hour from a hopper of a twin screw extruder (PCM-30L / D = 20 manufactured by Ikegai Iron Works). Then, 7% of potassium hydroxide was supplied from the supply port provided at the vent of the extruder.
The solution was continuously supplied at a rate of 550 g / hour and continuously extruded at a heating temperature of 170 ° C. The extruded resin mixture was cooled to 90 ° C. by a static mixer equipped with a jacket installed at the extruder outlet, and further poured into warm water at 80 ° C. to obtain an aqueous dispersion having a yield of 98% and a solid concentration of 32%. Obtained. The average particle size of the obtained aqueous dispersion was 3.4 μm as measured by Microtrack.

Example 3 The aqueous dispersions obtained in Examples 1 and 2 and Comparative Example 2 were each baked at 100 ° C. on a 100 μm-thick polyethylene terephthalate film (Toray, Lumilar) to form a 20 μm-thick coating. Formed. Using this as a sample, gas permeability was evaluated. The results are shown in Table 1.

Evaluation method; test model PERMATRAN C-IV (manufactured by MOCON) Test temperature 23 ° C. Test humidity 0% RH

[0040]

[Table 1]

[0041]

According to the present invention, an aqueous dispersion containing an ethylene-vinyl alcohol copolymer can be obtained at a high yield, and a film formed by the aqueous dispersion can be obtained from an ethylene-vinyl alcohol copolymer. The polymer has excellent properties (such as gas barrier properties).

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI C08J 3/075 CEX C08J 3/03 CEX C08K 5/09 C08L 29/04

Claims (4)

[Claims] (A) 100 parts by weight of an ethylene-vinyl alcohol copolymer (B) 0.01 to 10 mmol equivalent of -COO-group converted to -COO-group per 1 g of polymer chain A thermoplastic polymer having an intrinsic viscosity [η] of 0.15 dl / g or more, and an intrinsic viscosity [η] of 0.15 dl / g
1 to 400 parts by weight of a mixture of a thermoplastic polymer of less than (C) an anionic or nonionic surfactant
1 to 40 parts by weight and (D) water, and (B) a part or all of the -COO- group bonded to the polymer chain of the thermoplastic polymer is in a carboxylate state, and contains water. An aqueous dispersion having an amount of 5 to 90% by weight and a resin solid content being present as finely dispersed particles. (B) 0.01 to 1 in terms of -COO-groups per gram of the polymer, wherein -COO- groups bonded to the polymer chain are in a range of 0.01 to 1;
The intrinsic viscosity [η] is 0.1 at a concentration of 0 millimolar equivalent.
The mixing ratio of a mixture of a thermoplastic polymer of 5 dl / g or more and a thermoplastic polymer having an intrinsic viscosity [η] of less than 0.15 dl / g is in the range of 1/20 to 20/1. The aqueous dispersion according to claim 1, (B) 0.01 to 1 in terms of -COO-groups per gram of polymer (B).
The intrinsic viscosity [η] is 0.1 at a concentration of 0 millimolar equivalent.
2. A thermoplastic polymer having a viscosity of 5 dl / g or more and a thermoplastic polymer having an intrinsic viscosity [η] of less than 0.15 dl / g is an ethylene- (meth) acrylic acid copolymer. An aqueous dispersion as described. 4. A step of melt-kneading (A), (B) and (C), and adding a basic substance and 3 to 3 parts by weight to the melt-kneaded product.
An aqueous dispersion comprising a step of adding 40% by weight of water to carry out melt-kneading and inverting the solid phase of the resin into an aqueous dispersion, and if necessary, adding an additional amount of water to the aqueous dispersion. How to make the body.