JP6587375B2 - Aqueous polyolefin resin dispersion and process for producing the same - Google Patents

Description

  The present invention is an aqueous dispersion containing fine and stable polyolefin resin fine particles having a specific composition in an aqueous medium, and is a polyolefin resin aqueous solution suitable as a binder for various coating agents, primers, paints, inks, adhesives and the like. The present invention relates to a dispersion and a method for producing the same.

  Polyolefin resins such as propylene resin are excellent in electrical properties, mechanical properties, chemical properties, formability, hygiene, recyclability, etc., and are used mainly in automobiles, electricity, packaging, daily goods, and the like. However, since the polyolefin resin generally has no polar group in the molecular chain, there is a problem that it is difficult to apply and adhere to various substrates. For this reason, it has been proposed that when a polyolefin resin such as a propylene resin is applied or adhered, the polyolefin resin is chlorinated. However, since chlorinated resins generate harmful substances such as acid gas during incineration, the shift to non-chlorine materials is strongly desired in recent years as the concern for the environment increases.

  Therefore, development of modified polyolefin resins modified with acid or the like has been carried out. In order to use the modified polyolefin resin for application or adhesion, it is necessary to liquefy the resin. For example, a) the resin is used by melting, b) the resin is used by dissolving or dispersing in an organic solvent, c) A method in which a resin is dispersed in an aqueous medium is used. However, a) has a problem that its use is limited and it is difficult to reduce the thickness due to the melt viscosity of the resin. For this reason, although the aspect by b) and c) is said to be preferable, recently, there is a tendency that the use of organic solvents is restricted from the viewpoints of environmental protection, resource saving, regulation of dangerous goods by the Fire Service Act, and workplace environment improvement. And c) is most preferable.

  From the background as described above, studies on making the modified polyolefin resin aqueous have been actively conducted. For example, Patent Documents 1 to 9 describe a technique that uses a large amount of a surfactant as an essential component in order to stably disperse a modified polyolefin resin in an aqueous medium. A technique for obtaining an aqueous dispersion of a propylene-based polyolefin resin without using it is described. Patent Document 11 describes a technique using liquid polyol as an essential component.

JP-A-6-73250 Japanese Patent Laid-Open No. 6-80738 Japanese Patent Laid-Open No. 6-80844 Japanese Patent Laid-Open No. 6-80845 Japanese Patent Laid-Open No. 6-256592 JP-A-8-3376 JP-A-8-67726 JP-A-8-92427 Japanese Patent No. 2895574 International Publication No. 2004/104090 Japanese Patent No. 2610559

  However, in the inventions described in Patent Documents 1 to 9, the surfactant as described above is generally nonvolatile and remains in the coating film of the modified polyolefin resin even after drying. The water resistance of the coating film is significantly reduced. And since the tendency to bleed out from a coating film becomes strong as the usage-amount of surfactant increases, it is unpreferable also environmentally and hygienically, and there exists a possibility that a coating-film performance may change with time.

  Further, in the aqueous propylene-based resin dispersion according to the method described in Patent Document 10, no surfactant is used, and thus the above problems are not particularly observed. However, since the weight average particle diameter of the resin particles is relatively large, specifically more than 0.15 μm, there are some difficulties in film formation at low temperature and mixing stability with inorganic particles, There is room for improvement.

  In the invention described in Patent Document 11, since the liquid polyol to be used has high hydrophilicity, it is difficult to make the resin completely aqueous with only the polyol. In fact, even in the invention, a large amount of the surfactant is used together. ing. Therefore, the same problems as those of the inventions described in Patent Documents 1 to 9 occur in this invention. In this regard, even if the resin can be made aqueous with only a liquid polyol, for example, by increasing the carboxyl group content of the resin, the polyol has a high boiling point. It remains in the film. In this case, not only the water resistance of the coating film and the adhesion to the base material are deteriorated, but also there is a possibility of bleeding out from the coating film. There is a risk of doing. In addition, in order to volatilize the polyol, drying at a high temperature for a long time is necessary, which is industrially disadvantageous, and there is a problem that the substrate is deformed depending on conditions.

  The present invention eliminates the above-mentioned drawbacks of the prior art, and fine and stable polyolefin resin fine particles having a specific composition in an aqueous medium without using a large amount of a non-volatile aqueous agent such as a surfactant. It is an object of the present invention to provide an aqueous dispersion that is contained in a desired manner and a preferred method for producing the same.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have devised a process for aqueous dispersion using a propylene-based polyolefin resin having a specific composition, so that a large amount of non-volatile aqueous additive is not used. In both cases, an unexpected effect that the resin can be dispersed very finely in an aqueous medium has been found, and the present invention has been achieved.

  That is, the gist of the present invention is as follows.

(1) The olefin component consists only of the propylene component (A) and the butene component (B), the mass ratio (A / B) is in the range of 60/40 to 95/5, and the total amount of olefin components (A + B) 100 An aqueous dispersion containing a polyolefin resin containing 0.5 to 15 parts by mass of an unsaturated carboxylic acid unit relative to parts by mass, and an aqueous medium, wherein the weight average particle diameter of the polyolefin resin in the aqueous dispersion is and at 0.10μm or less, and state, and are dispersity of 1.5 or less according to the particle size distribution, the polyolefin resin aqueous dispersion characterized by containing substantially no non-volatile water-aid.
(2) (1) Symbol coating agent comprising a polyolefin resin aqueous dispersion of the mounting, primer, paint, ink or adhesive.
( 3 ) After heating and stirring a polyolefin resin, a basic compound, an organic solvent, and water in a sealed container at a temperature of 80 to 240 ° C., at least one of the basic compound, the organic solvent, and water is added to the sealed container. method for producing in heating at a temperature of 80 to 240 ° C., characterized by stirring (1) Symbol placement of the polyolefin resin aqueous dispersion.
( 4 ) After heating and stirring the polyolefin resin, basic compound, organic solvent and water in a sealed container at a temperature of 80 to 240 ° C., adding at least one of the basic compound, organic solvent and water in the sealed container in heating at a temperature of 80 to 240 ° C., and stirred, then, at least a portion, and removing (1) Symbol placement method for producing a polyolefin resin aqueous dispersion of the organic solvent.

  The aqueous dispersion of the present invention is an aqueous dispersion containing a polyolefin resin having a specific composition, and exhibits a very finely dispersed state having a weight average particle diameter of 0.15 μm or less. The aqueous dispersion of the present invention is excellent in mixing stability with various materials such as inorganic particles, and is suitable for use as a binder for various coating agents, primers, paints, inks, adhesives and the like.

  In addition, when the aqueous dispersion of the present invention is prepared without using the non-volatile aqueous auxiliary agent, the coating film does not contain the non-volatile aqueous auxiliary agent, so that the original properties of the polyolefin resin are not impaired, which is preferable. . In addition, by not using a non-volatile aqueous additive, it is possible to ensure sufficient adhesion and water resistance of the coating film even when it is dried at a lower temperature and in a shorter time than in the past during film formation. These performances hardly change.

  Furthermore, according to the production method of the present invention, such an aqueous dispersion can be stably produced at a low cost.

  The present invention will be described in detail below.

  First, the polyolefin resin will be described.

  The polyolefin resin in the present invention contains, as an olefin component, a propylene component (A) and an olefin component (B) other than the propylene component in a mass ratio (A / B) of 60/40 to 95/5. From the viewpoint of reducing the dispersed particle size and improving the adhesion of the coating film to the polypropylene (PP) substrate, the mass ratio of the propylene component (A) to the olefin component (B) other than the propylene component (A / B) needs to be in the range of 60/40 to 95/5, and preferably in the range of 60/40 to 80/20. When the proportion of the propylene component is less than 60% by mass, the adhesiveness to the PP base material is lowered, and when it exceeds 95% by mass, the dispersed particle size becomes large and it may be difficult to disperse the resin in water. .

  Examples of the olefin component (B) other than the propylene component include ethylene, 1-butene, isobutene, 1-pentene, 4-methyl-1-pentene, 3-methyl-1-pentene, 1-hexene, 1-octene and norbornenes. And alene such as butadiene, and dienes such as butadiene and isoprene. Among them, butene components (1-butene, isobutene, etc.) are included in terms of ease of resin production, ease of water treatment, adhesion to various materials, particularly adhesion to a PP substrate, and blocking properties. Is preferred.

  In the above polyolefin resin, the copolymerization form of each component is not limited, and examples thereof include random copolymerization, block copolymerization, and graft copolymerization. From the viewpoint of ease of polymerization, random copolymerization is required. Is preferred. Moreover, you may mix and use multiple types of polyolefin resin as needed.

  The polyolefin resin in the present invention may contain components other than those described above as necessary. Other components include (meth) acrylates such as methyl (meth) acrylate, ethyl (meth) acrylate, and butyl (meth) acrylate, maleic acid such as dimethyl maleate, diethyl maleate, and dibutyl maleate. Acid esters, (meth) acrylic amides, alkyl vinyl ethers such as methyl vinyl ether and ethyl vinyl ether, vinyl esters such as vinyl formate, vinyl acetate, vinyl propionate, vinyl pivalate, vinyl versatate and vinyl esters Vinyl alcohol, 2-hydroxyethyl acrylate, glycidyl (meth) acrylate, (meth) acrylonitrile, styrene, substituted styrene, vinyl halides, vinylidene halides, carbon monoxide, two Sulfur, and the like, may be a mixture thereof.

  As content (mass ratio) of another component, generally 10 mass% or less of the whole polyolefin resin is preferable.

  In the present invention, a commercially available polyolefin resin may be used. Examples include Exelen from Sumitomo Chemical Co., Ltd., Tough Selenium Series, Tuffmer Series from Mitsui Chemicals, APAO Series (Amorphous Polyalphaolefin) from REXtac, Ricosen PP Series from Clariant, Evonik Degussa Examples include best plasts made by the manufacturer. In addition, when using a commercially available polyolefin resin that is not acid-modified, an unsaturated carboxylic acid unit may be introduced by a known method.

From the viewpoint of dispersibility, the polyolefin resin in the present invention needs to contain 0.5 to 15 parts by mass of an unsaturated carboxylic acid unit with respect to 100 parts by mass of the total amount of olefin components (A + B) contained in the polyolefin resin. is there. Preferably 0.5 to 10 parts by weight, more preferably from 0.5 to 8 parts by weight, more preferably 1 to 7 parts by weight, and most preferably 1.5 to 7 parts by weight. If the unsaturated carboxylic acid unit is less than 0.5 parts by mass, it will be difficult to make the polyolefin resin water-based. On the other hand, if the unsaturated carboxylic acid unit exceeds 15 parts by mass, it will be easy to make the resin aqueous. Adhesion to the material may be reduced.

  As unsaturated carboxylic acid units, acrylic acid, methacrylic acid, maleic acid, maleic anhydride, itaconic acid, itaconic acid, aconitic acid, aconitic anhydride, fumaric acid, crotonic acid, citraconic acid, mesaconic acid, allyl succinic acid, etc. In addition, compounds having at least one carboxyl group or acid anhydride group in the molecule (in the monomer unit), such as unsaturated dicarboxylic acid half esters and half amides, can also be used. Of these, maleic anhydride, acrylic acid and methacrylic acid are preferred, and maleic anhydride is more preferred from the viewpoint of easy introduction into the unmodified polyolefin resin. Then, in the present invention, since the butene component is suitable as the olefin component (B) other than propylene as described above, a propylene / butene / maleic anhydride terpolymer is preferably used as the polyolefin resin. It will be.

  The unsaturated carboxylic acid unit is not particularly limited as long as it is copolymerized in the polyolefin resin. Examples thereof include random copolymerization, block copolymerization, and graft copolymerization. In addition, the acid anhydride unit introduced into the polyolefin resin is likely to have an acid anhydride structure in a dry state, and a part or all of the ring is opened in an aqueous medium containing a basic compound to be described later. It tends to be its salt.

  The method for introducing the unsaturated carboxylic acid unit into the unmodified polyolefin resin is not particularly limited. For example, in the presence of a radical generator, the unmodified polyolefin resin and the unsaturated carboxylic acid are heated and melted to a temperature equal to or higher than the melting point of the unmodified polyolefin resin. Graft copolymerization of unsaturated carboxylic acid units to the unmodified polyolefin resin, such as by reacting the unmodified polyolefin resin in an organic solvent and then heating and stirring in the presence of a radical generator. The method of doing is mentioned. The former method is preferable because the operation is simple. Examples of the radical generator used for graft copolymerization include di-tert-butyl peroxide, dicumyl peroxide, tert-butyl hydroperoxide, tert-butyl cumyl peroxide, benzoyl peroxide, dilauryl peroxide, Examples thereof include organic peroxides such as cumene hydroperoxide, tert-butyl peroxybenzoate, ethyl ethyl ketone peroxide, and di-tert-butyl diperphthalate, and azonitriles such as azobisisobutyronitrile. These may be appropriately selected and used depending on the reaction temperature.

  As a weight average molecular weight of the polyolefin resin in this invention, it is preferable that it is 5000-200000, It is more preferable that it is 10,000-150,000, It is more preferable that it is 20000-120,000, It is especially preferable that it is 30000-100000. Most preferably, it is 35000-80000. When the weight average molecular weight is less than 5,000, the adhesion to the substrate tends to decrease, or the resulting coating film tends to be brittle. On the other hand, when the weight average molecular weight exceeds 200,000, it tends to be difficult to make the resin water-based. In addition, the weight average molecular weight of resin can be calculated | required on the basis of polystyrene resin using a gel permeation chromatography (GPC).

  In the aqueous dispersion of the present invention, the above polyolefin resin is dispersed or dissolved in an aqueous medium. Here, the aqueous medium is a liquid containing water as a main component, and may contain an organic solvent or a basic compound described later.

  The polyolefin resin particles dispersed in the aqueous dispersion of the present invention have a weight average particle size of 0.15 μm or less. Furthermore, from the viewpoint of low-temperature film-forming properties, the weight average particle diameter is preferably 0.12 μm or less, more preferably 0.10 μm or less, and further preferably 0.001 to 0.10 μm. When the number average particle diameter exceeds 0.15 μm, the low-temperature film-forming property is deteriorated or the mixing stability with other materials is deteriorated.

  Moreover, in this invention, it is preferable that the dispersion degree concerning the particle diameter distribution of polyolefin resin is 2.6 or less. In particular, from the viewpoint of the smoothness of the coating film, the degree of dispersion is preferably 2.0 or less, more preferably 1.5 or less, and even more preferably 1.3 or less. When the degree of dispersion exceeds 2.6, the smoothness and adhesion of the coating film tend to decrease.

  The resin content in the aqueous dispersion of the present invention can be appropriately selected according to the film forming conditions, the thickness of the coating film, performance, etc., and is not particularly limited, but the viscosity of the aqueous dispersion is appropriately maintained, And 1-60 mass% is preferable at the point which expresses favorable coating-film formation ability, 3-55 mass% is more preferable, 5-50 mass% is further more preferable, and 10-45 mass% is especially preferable.

  It is preferable that the aqueous dispersion of the present invention does not substantially contain a nonvolatile aqueous solubilizing aid. Although the present invention does not exclude the use of a non-volatile aqueous additive, the polyolefin resin can be stably incorporated into an aqueous medium within a weight average particle size of 0.15 μm or less without using an aqueous additive. Can be dispersed. For this reason, the coating film characteristic in low temperature drying, especially water resistance, adhesiveness with a base material, and heat sealability are excellent, and these performances hardly change in the long term.

  Here, the “aqueous auxiliary” means a drug or compound added for the purpose of promoting aqueous formation or stabilizing the aqueous dispersion in the production of an aqueous dispersion, and “nonvolatile” means It means that it does not have a boiling point at normal pressure or has a high boiling point (for example, 300 ° C. or higher) at normal pressure.

  “Substantially free of non-volatile aqueous additive” means that such an auxiliary is not used during production (when the aqueous resin is made), and the resulting dispersion does not contain this auxiliary as a result. means. Therefore, it is particularly preferable that the content of such an aqueous auxiliary agent is zero, but within a range not impairing the effects of the present invention, it is 5% by mass or less, preferably 2% by mass or less, and more preferably 2% by mass or less. Preferably, it may be contained less than about 0.5% by mass.

  Examples of the non-volatile auxiliary agent used in the present invention include an emulsifier described later, a compound having a protective colloid action, a modified wax, an acid-modified compound having a high acid value, and a water-soluble polymer.

  Examples of the emulsifier include a cationic emulsifier, an anionic emulsifier, a nonionic emulsifier, and an amphoteric emulsifier. In addition to those generally used for emulsion polymerization, surfactants are also included. For example, anionic emulsifiers include higher alcohol sulfates, higher alkyl sulfonates, higher carboxylates, alkyl benzene sulfonates, polyoxyethylene alkyl sulfate salts, polyoxyethylene alkyl phenyl ether sulfate salts, vinyl sulfosuccinates. Nonionic emulsifiers include polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyethylene glycol fatty acid ester, ethylene oxide propylene oxide block copolymer, polyoxyethylene fatty acid amide, ethylene oxide-propylene oxide. Compounds having a polyoxyethylene structure such as copolymers and sorbitan derivatives such as polyoxyethylene sorbitan fatty acid esters And examples of the amphoteric emulsifiers, lauryl betaine, lauryl dimethyl amine oxide, and the like.

  Compounds having protective colloid action, modified waxes, acid-modified compounds with high acid values, water-soluble polymers include polyvinyl alcohol, carboxyl group-modified polyvinyl alcohol, carboxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, modified starch, polyvinyl pyrrolidone , Polyacrylic acid and salts thereof, carboxyl group-containing polyethylene wax, carboxyl group-containing polypropylene wax, carboxyl group-containing polyethylene-propylene wax, and other acid-modified polyolefin waxes having a number average molecular weight of usually 5000 or less and salts thereof, acrylic acid-anhydride Maleic acid copolymer and its salt, styrene- (meth) acrylic acid copolymer, ethylene- (meth) acrylic acid copolymer, isobutylene-maleic anhydride A carboxyl group-containing polymer having an unsaturated carboxylic acid content of 10% by mass or more, such as a copolymer, (meth) acrylic acid- (meth) acrylic ester copolymer, and a salt thereof, polyitaconic acid and a salt thereof, and an amino group. Examples thereof include water-soluble acrylic copolymers, gelatin, gum arabic, casein, and the like compounds generally used as fine particle dispersion stabilizers.

  On the other hand, basic compounds include ammonia, triethylamine, N, N-dimethylethanolamine, isopropylamine, aminoethanol, dimethylaminoethanol, diethylaminoethanol, ethylamine, diethylamine, isobutylamine, dipropylamine, 3-ethoxypropylamine, 3-diethylaminopropylamine, sec-butylamine, propylamine, n-butylamine, 2-methoxyethylamine, 3-methoxypropylamine, 2,2-dimethoxyethylamine, monoethanolamine, morpholine, N-methylmorpholine, N-ethylmorpholine , Pyrrole, pyridine and the like. The compounding amount of the basic compound is preferably 0.5 to 10 times equivalent to the carboxyl group in the polyolefin resin, more preferably 0.8 to 5 times equivalent, and 0.9 to 3.0 times equivalent. Is particularly preferred. If it is less than 0.5 times equivalent, the addition effect of a basic compound is not recognized, and if it exceeds 10 times equivalent, drying time at the time of coating film formation may become long, or the stability of an aqueous dispersion may fall.

  In the present invention, it is preferable to add an organic solvent at the time of aqueous formation in order to promote the aqueous formation of the polyolefin resin and reduce the dispersed particle size. As content of an organic solvent, 50 mass% or less is preferable with respect to the whole aqueous medium, It is more preferable that it is 1-45 mass%, 2-40 mass% is further more preferable, 3-35 mass% is especially preferable. When the content of the organic solvent exceeds 50% by mass, it cannot be regarded as an aqueous medium substantially and does not deviate from one of the objects of the present invention (environmental protection). Body stability may be reduced.

  The organic solvent preferably has a solubility in water at 20 ° C. of 10 g / L or more, more preferably 20 g / L or more, and 50 g / L or more from the viewpoint of obtaining an aqueous dispersion having good dispersion stability. Is more preferable.

  As the organic solvent, those having a boiling point of 150 ° C. or less are preferable from the viewpoint of efficiently removing them from the coating film in the course of film formation. An organic solvent having a boiling point exceeding 150 ° C. tends to be difficult to scatter from the coating film by drying, and the water resistance of the coating film at low temperature drying, adhesion to the substrate, etc. may be deteriorated. . Preferred organic solvents include, for example, methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, sec-butanol, tert-butanol, n-amyl alcohol, isoamyl alcohol, sec-amyl alcohol, tert-amyl alcohol. , Alcohols such as 1-ethyl-1-propanol, 2-methyl-1-butanol, n-hexanol and cyclohexanol, ketones such as methyl ethyl ketone, methyl isobutyl ketone, ethyl butyl ketone and cyclohexanone, ethers such as tetrahydrofuran and dioxane , Ethyl acetate, n-propyl acetate, isopropyl acetate, n-butyl acetate, isobutyl acetate, sec-butyl acetate, 3-methoxybutyl acetate, methyl propionate , Esters such as ethyl propionate, diethyl carbonate, dimethyl carbonate, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, glycol derivatives such as ethylene glycol ethyl ether acetate, 1-methoxy-2-propanol, 1-ethoxy-2-propanol, 3-methoxy-3-methyl-1-butanol, methoxybutanol, acetonitrile, dimethylformamide, dimethylacetamide, diacetone alcohol, ethyl acetoacetate, 1,2 -Dimethyl glycerol, 1, 3- dimethyl glycerol, a trimethyl glycerol, etc. are mentioned. In the present invention, a mixture of these organic solvents may be used.

  Among the above organic solvents, ethanol, n-propanol, isopropanol, n-butanol, methyl ethyl ketone, cyclohexanone, tetrahydrofuran, dioxane, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether are resins. It is more effective and effective in promoting aqueous formation.

  Next, an example of the method for producing the aqueous polyolefin resin dispersion will be described.

  The method for obtaining the aqueous polyolefin resin dispersion of the present invention is not particularly limited. However, the above-described components, that is, a polyolefin resin, an aqueous medium, an organic solvent, a basic compound and the like as required can be sealed. Among them, a method of heating and stirring can be adopted, and this method is most preferable.

  As the container, an apparatus widely known to those skilled in the art as a solid / liquid stirring apparatus or an emulsifier can be used, and an apparatus capable of pressurization of 0.1 MPa or more is preferably used. The stirring method and the rotation speed of the stirring are not particularly limited, but may be stirring at a low speed such that the resin is in a floating state in the aqueous medium. Therefore, high-speed stirring (for example, 1000 rpm or more) is not essential, and an aqueous dispersion can be produced with a simple apparatus.

  For example, raw materials such as a polyolefin resin and an aqueous medium are charged into the above apparatus, and the mixture is preferably stirred and mixed at a temperature of 40 ° C. or lower. Next, while maintaining the temperature in the tank at 80 to 240 ° C., preferably 100 to 220 ° C., more preferably 110 to 200 ° C., particularly preferably 100 to 190 ° C., preferably until coarse particles disappear (for example, Continue stirring (5 to 300 minutes). Then, at least 1 sort (s) chosen from a basic compound, an organic solvent, and water is further added in a system, and it heats and stirs again in the airtight container at the temperature of 80-240 degreeC. By carrying out like this, the weight average particle diameter of polyolefin resin can be made into the range of 0.15 micrometer or less. Moreover, it is preferable to make the resin aqueous by the two-step process as described above in order to adjust the degree of dispersion of the particle size distribution to a preferable range.

  In addition, what is necessary is just to determine suitably the ratio of the basic compound, organic solvent, or water to mix | blend suitably according to solid content concentration, particle diameter, dispersion degree, etc. which are desired. The method of adding a basic compound, an organic solvent, or water is not particularly limited, but there are a method of using a gear pump to add under pressure, a method of once lowering the system temperature, and a method of opening and adding. The total amount of the basic compound, organic solvent or water to be added is preferably adjusted so that the solid content concentration after mixing is 1 to 50% by mass, more preferably 2 to 45% by mass. An amount of ˜40% by weight is particularly preferred.

  In the said process, when the temperature in a tank will be less than 80 degreeC, the water-based polyolefin resin will become difficult to advance. On the other hand, when the temperature in the tank exceeds 240 ° C., the molecular weight of the polyolefin resin may decrease.

  When the above organic solvent is used during the production of the aqueous dispersion, after the resin is made aqueous, a part thereof is distilled out of the system by a solvent removal process generally referred to as “stripping”. The content may be reduced. By stripping, the content of the organic solvent in the aqueous dispersion can be 10% by mass or less, and if it is 5% by mass or less, it is environmentally preferable. In the stripping process, it is possible to distill off substantially all of the organic solvent used to make the aqueous solution, but it is necessary to increase the degree of vacuum of the equipment and lengthen the operation time. In consideration, the lower limit of the organic solvent content is preferably about 0.01% by mass. However, even if it is less than 0.01% by mass, there is no particular influence on performance, and there is no problem in use.

  Examples of the stripping method include a method in which the aqueous dispersion is heated with stirring at normal pressure or reduced pressure to distill off the organic solvent. Further, since the solid content concentration is increased by distilling off the aqueous medium, for example, in the case where the viscosity increases and the workability deteriorates, water may be added to the aqueous dispersion in advance. Good.

  Examples of a method for adjusting the solid content concentration of the aqueous dispersion thus obtained include a method in which the aqueous medium is distilled off or diluted with water so as to obtain a desired solid content concentration.

  By employing the production method of the present invention, the polyolefin resin can be efficiently dispersed or dissolved in an aqueous medium, and can be prepared in a uniform liquid state. Here, the uniform liquid state means that, in terms of appearance, a portion where the solid content concentration is locally different from other portions such as precipitation, phase separation or skinning is not found in the aqueous dispersion. Say.

  The coating film obtained from the aqueous dispersion of the present invention is excellent in adhesiveness to various substrates such as metals, glass, plastic materials, films, synthetic paper, paper, etc. It is suitable as a coating agent, paint, ink and adhesive for the substrate.

  Other polymers, tackifiers, inorganic particles, cross-linking agents, pigments, dyes, and the like can be added to the aqueous dispersion of the present invention in order to further improve performance according to the purpose.

  Other polymers and tackifiers are not particularly limited. For example, polyvinyl acetate, ethylene-vinyl acetate copolymer, polyvinyl chloride, polyvinylidene chloride, ethylene- (meth) acrylic acid copolymer, ethylene- (meth) acrylic acid ester-maleic anhydride copolymer, styrene -Maleic acid resin, styrene-butadiene resin, butadiene resin, acrylonitrile-butadiene resin, poly (meth) acrylonitrile resin, (meth) acrylamide resin, chlorinated polyethylene resin, chlorinated polypropylene resin, polyester resin, modified nylon resin, urethane resin , Tackifying resins such as rosin, phenol resins, silicone resins, epoxy resins and the like, and a plurality of them may be mixed and used as necessary. In addition, although these polymers may be used in the solid state, it is preferable to use those processed into an aqueous dispersion from the viewpoint of maintaining the stability of the aqueous dispersion.

  Examples of inorganic particles include metal oxides such as magnesium oxide, zinc oxide and tin oxide, inorganic particles such as calcium carbonate and silica, and layered inorganic compounds such as vermiculite, montmorillonite, hectorite, hydrotalcite and synthetic mica. Can be used. The average particle diameter of these inorganic particles is preferably 0.005 to 10 μm, more preferably 0.005 to 5 μm from the viewpoint of the stability of the aqueous dispersion. In addition, a plurality of inorganic particles may be mixed and used. Here, zinc oxide can be used for ultraviolet shielding, and tin oxide can be used for antistatic purposes.

  As the crosslinking agent, a crosslinking agent having self-crosslinking property, a compound having a plurality of functional groups that react with a carboxyl group in the molecule, a metal having a multivalent coordination site, and the like can be used. Specifically, isocyanate compounds, melamine compounds, urea compounds, epoxy compounds, carbodiimide compounds, oxazoline group-containing compounds, zirconium salt compounds, silane coupling agents and the like are preferable. A plurality of these crosslinking agents may be used simultaneously.

  As a usage-amount of a crosslinking agent, from a viewpoint of improving the water resistance of a coating film, solvent resistance, etc., 0.01-80 mass parts with respect to 100 mass parts of resin, Preferably it is 0.1-50 mass parts, More preferably Is preferably added in an amount of 0.5 to 30 parts by mass. When the amount of the crosslinking agent used is less than 0.01 parts by mass, improvement in coating film performance tends not to be expected, and when it exceeds 80 parts by mass, workability and other performances are degraded.

  Examples of pigments and dyes include titanium oxide, zinc white, and carbon black, and any of disperse dyes, acid dyes, cationic dyes, reactive dyes, and the like can be used.

  If necessary, various agents such as a leveling agent, an antifoaming agent, an anti-waxing agent, a pigment dispersant, an ultraviolet absorber, a thickener, a weathering agent, a flame retardant are added to the aqueous dispersion of the present invention. It is also possible.

  Next, a method for using the aqueous polyolefin resin dispersion of the present invention will be described.

  The aqueous dispersion of the present invention is excellent in coating film forming ability. For film formation, a known method such as gravure roll coating, reverse roll coating, wire bar coating, lip coating, air knife coating, curtain flow coating, spray coating, dip coating, or brush coating can be employed. Specifically, an aqueous dispersion is uniformly applied to the surfaces of various substrates, set as near room temperature as necessary, and then subjected to heat treatment for drying or drying and baking, thereby forming a uniform coating film. It can be formed by bonding to various substrate surfaces. As a heating device at this time, a normal hot air circulation type oven, an infrared heater, or the like may be used. The heating temperature and the heating time are appropriately selected depending on the properties of the substrate to be coated and the above-mentioned various materials that can be arbitrarily mixed in the aqueous dispersion. In consideration, the heating temperature is preferably 30 to 250 ° C, more preferably 60 to 230 ° C, and particularly preferably 80 to 210 ° C. On the other hand, the heating time is preferably 1 second to 20 minutes, more preferably 5 seconds to 15 minutes, and particularly preferably 5 seconds to 10 minutes. In addition, when a crosslinking agent is added, in order to sufficiently advance the reaction between the carboxyl group in the polyolefin resin and the crosslinking agent, it is desirable to appropriately select the heating temperature and time depending on the type of the crosslinking agent.

As the coating amount of the aqueous dispersion of the present invention, but are those selected appropriately depending on the application, 0.01 to 100 g / m @ 2 are preferred as the coating amount after drying, 0.1 to 50 g / m ² Is more preferable, and 0.2 to 30 g / m ² is particularly preferable. If the film is formed so as to be in the range of 0.01 to 100 g / m ^2, a coating film having excellent uniformity can be obtained.

  In addition, in order to adjust the coating amount, in addition to appropriately selecting an apparatus used for coating and its use conditions, an aqueous dispersion whose concentration is adjusted according to the desired thickness of the coating film should be used. Is preferred. The concentration at this time can be adjusted by the charged composition at the time of preparation. Further, the aqueous dispersion once prepared may be adjusted by appropriately diluting or concentrating.

  The aqueous polyolefin resin dispersion of the present invention can be suitably used as a coating agent, primer, paint, ink, adhesive and the like.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto.

  Various characteristics were measured or evaluated by the following methods.

1. Polyolefin resin (1) Content of unsaturated carboxylic acid unit The content was determined by infrared absorption spectrum analysis (Perkin Elmer System-2000 Fourier transform infrared spectrophotometer, resolution 4 cm ⁻¹ ).
(2) Constitution of resin other than unsaturated carboxylic acid unit ¹ H-NMR and ¹³ C-NMR analysis (manufactured by Varian, 300 MHz) was carried out at 120 ° C. in orthodichlorobenzene (d ₄ ). ^{In 13} C-NMR analysis, measurement was performed based on a gated decoupling method in consideration of quantitativeness.
(3) Weight average molecular weight of resin The weight average molecular weight is measured by GPC analysis (HLC-8020 manufactured by Tosoh Corporation, column is TSK-GEL), and the sample is dissolved in tetrahydrofuran and measured at 40 ° C. The weight average molecular weight was determined from the calibration curve prepared in (1). Ortho-dichlorobenzene was used when it was difficult to dissolve in tetrahydrofuran.

2. Aqueous dispersion (1) Number average particle diameter and weight average particle diameter of polyolefin resin particles, and degree of dispersion Using a Microtrac particle size distribution analyzer UPA150 (MODEL No. 9340) manufactured by Nikkiso Co., Ltd., the number average particle diameter (mn) And the weight average particle diameter (mw) was measured. The refractive index of the resin was 1.5.
The degree of dispersion was calculated based on the formula: degree of dispersion = weight average particle diameter (mw) / number average particle diameter (mn).
(2) Pot life The appearance when the aqueous dispersion was left at room temperature for 90 days was evaluated in the following three stages.
○: No change in appearance.
Δ: Thickening is observed.
X: Solidification, aggregation and precipitation are observed.
When the appearance evaluation was “◯”, the number average particle size was measured based on the above method.
(3) Stability of mixing An aqueous dispersion of polyolefin resin and an aqueous dispersion containing carbon black as a pigment (made by Lion Corporation, Lion Paste W-376R) are mixed with carbon black based on 100 parts by mass of the solid content of the polyolefin resin. It mix | blended so that it might become 80 mass parts in conversion of solid content, the propeller stirring was carried out, and the water-based coating material was produced. The obtained paint was allowed to stand at 40 ° C. for 30 days, and the state of the paint was visually observed and evaluated in the following three stages.
○: No aggregate or phase separation △: No phase separation but small amount of aggregate ×: Large amount of aggregate or phase separation

3. Coating (1) Water resistance On an untreated surface of a stretched polypropylene film (manufactured by Tosero, OP U-1, thickness 20 μm), the coating amount after drying the aqueous dispersion is about 2 g / m ^2. It was applied using a bar and dried at 60 ° C. for 3 days. The coated film thus produced was immersed in warm water at 40 ° C. for 24 hours, and then the state of the coated surface was visually observed and evaluated in the following three stages.
○: No change in appearance.
(Triangle | delta): A coating film whitens.
X: A coating layer melt | dissolves or peels.
(2) Adhesiveness to PP base material Using a Mayer bar so that the coating amount after drying the aqueous dispersion on a PP molded piece (PP is Nippon Polypropylene, Novatec PP MA3) is about 2 g / m ^2. And dried at 130 ° C. for 10 minutes. Thereafter, an adhesive tape (TF-12 manufactured by Nichiban Co., Ltd.) was pasted on the coating surface, and the tape was peeled off vigorously. The state of the coating surface was visually observed and evaluated in the following three stages.
○: No peeling at all.
Δ: Some peeling occurred.
X: All peeled off.

(Production Example 1: Production of polyolefin resin P-1)
280 g of propylene-butene copolymer (mass ratio: propylene / butene = 80/20) was heated and melted in a four-necked flask under a nitrogen atmosphere, and then the system temperature was kept at 170 ° C. while stirring, and the mixture was unsaturated. A polyolefin resin P-1 was obtained by adding 25.0 g of maleic anhydride as a carboxylic acid and 6.0 g of dicumyl peroxide as a radical generator over 1 hour, followed by reaction for 1 hour. The properties of the obtained resin are shown in Table 1.

(Production Examples 2, 4, and 5: Production of polyolefin resins P-2, P-4, and P-5)
The same as Production Example 1, except that the mass ratio of propylene / butene was changed to propylene / butene = 65/35 (P-2), 97/3 (P-4), and 50/50 (P-5), respectively. Polyolefin resins P-2, P-4 and P-5 were obtained by the method.

(Production Example 3: Production of polyolefin resin P-3)
A polyolefin resin P-3 was obtained in the same manner as in Production Example 1, except that a propylene-ethylene copolymer (mass ratio: propylene / ethylene = 92/8) was used instead of the propylene-butene copolymer. .

(Production Example 6: Production of polyolefin resin P-6)
The same as in Production Example 1 except that the amount of maleic anhydride added is changed to 3.0 g instead of 25.0 g, and the amount of dicumyl peroxide added is changed to 2.0 g instead of 6.0 g. Polyolefin resin P-6 was obtained by this method.

  Table 1 shows the properties of the polyolefin resins P-2 to P-6 obtained above.

( Reference Example 2 )
60.0 g of polyolefin resin (P-1), 45.0 g of ethylene glycol-n-butyl ether (manufactured by Wako Pure Chemical Industries, Ltd.), 8 0.0 g of N, N-dimethylethanolamine and 137.0 g of distilled water were placed in a glass container and stirred at a rotation speed of the stirring blade of 300 rpm. It was confirmed that Therefore, while maintaining this state, the heater was turned on and heated after 10 minutes. Then, the system temperature was kept at 160 ° C. and further stirred for 60 minutes. Thereafter, it is cooled by air cooling until the internal temperature becomes 80 ° C., opened, and 45.0 g of tetrahydrofuran (manufactured by Wako Pure Chemical Industries, Ltd.), 5.0 g of N, N-dimethylethanolamine and 30.0 g of distillation. Water was added. Thereafter, the mixture was sealed, and the stirring speed was 300 rpm, the system temperature was kept at 140 ° C., and the mixture was further stirred for 60 minutes. Then, after cooling to room temperature (about 25 ° C.) while stirring with air rotation at 300 rpm, pressure filtration (air pressure 0.2 MPa) is performed with a 300 mesh stainless steel filter (wire diameter 0.035 mm, plain weave). A slightly cloudy aqueous dispersion was obtained. At this time, almost no resin remained on the filter. Table 2 shows various characteristics of the aqueous dispersion and the coating film obtained therefrom.

(Example 2, Reference Example 3 , Comparative Examples 1 and 2)
The same as Reference Example 2 except that P-2 (Example 2), P-3 ( Reference Example 3 ), P-4 (Comparative Example 1) or P-5 (Comparative Example 2) was used as the polyolefin resin. An aqueous dispersion was obtained by the method.

( Reference Example 4 )
250 g of the aqueous dispersion obtained in Reference Example 2 and 120 g of distilled water were charged into a 0.5 L two-necked round bottom flask, a mechanical stirrer and a Liebig condenser were installed, and the flask was heated in an oil bath. The aqueous medium was distilled off. When about 120 g of the aqueous medium was distilled off, heating was terminated and the mixture was cooled to room temperature. After cooling, the liquid component in the flask was subjected to pressure filtration (air pressure 0.2 MPa) with a 300-mesh stainless steel filter (wire diameter 0.035 mm, plain weave) to obtain a milky white uniform polyolefin resin aqueous dispersion.

(Comparative Example 3)
Dispersion was performed in the same manner as in Reference Example 2 except that P-6 was used as the polyolefin resin. As a result, a large amount of resin was confirmed on the filter. Thereby, it is recognized that dispersion | distribution did not advance substantially.

(Comparative Example 4)
In Reference Example 2 , all the raw materials were charged at once to obtain an aqueous dispersion. That is, 60.0 g of polyolefin resin (P-1), 45.0 g of ethylene glycol-n-butyl ether (manufactured by Wako Pure Chemical Industries, Ltd.) using a stirrer equipped with a 1 L glass container that can be sealed with a heater. 45.0 g of tetrahydrofuran (manufactured by Wako Pure Chemical Industries, Ltd.), 13.0 g of N, N-dimethylethanolamine and 167.0 g of distilled water were charged in a glass container and stirred at a stirring blade rotation speed of 300 rpm. No resin precipitation was observed at the bottom of the container, and it was confirmed that the container was in a floating state. Therefore, while maintaining this state, the heater was turned on and heated after 10 minutes. Then, the system temperature was kept at 160 ° C. and further stirred for 120 minutes. Then, it cooled to room temperature (about 25 degreeC), stirring with air-cooling with the rotational speed of 300 rpm, and pressure-filtering (air pressure 0.2MPa) with the 300 mesh stainless steel filter (wire diameter 0.035mm, plain weave). As a result, a large amount of resin was confirmed on the filter. Thereby, it is recognized that dispersion | distribution did not advance substantially.

(Reference Example 1)
In Reference Example 2 , Neugen EA-190D (manufactured by Daiichi Kogyo Seiyaku Co., Ltd., nonionic surfactant), which is a non-volatile aqueous agent, was added so as to be 3% by mass relative to the total mass of the polyolefin resin component. Except for the above, the resin was made aqueous by the method according to Reference Example 2 to obtain an aqueous dispersion.

Table 2 shows various properties of the aqueous dispersions obtained in Example 2 , Reference Examples 3 to 4 , Comparative Examples 1 to 2 and Reference Example 1 and the coating films obtained therefrom.

In the aqueous dispersion according to Example 2 , the water resistance of the coating film obtained at low temperature and the adhesiveness to the PP substrate were good. Moreover, the mixing stability with the carbon black dispersion was also good.

  On the other hand, in Comparative Example 1, since the composition of the polyolefin resin did not satisfy the configuration of the present invention (the amount of propylene component was large), a tendency to increase the particle diameter was recognized, and therefore the particle diameter range was determined in the present invention. I have fallen out of the specified range. In addition, the water resistance of the coating film formed at low temperature was inferior. Furthermore, the mixing stability with the carbon black dispersion was poor. On the other hand, in Comparative Example 2, the composition of the polyolefin resin did not satisfy the configuration of the present invention (the propylene component was small), resulting in poor adhesion to the PP substrate.

  Moreover, in Comparative Example 3, since the content of the unsaturated carboxylic acid component was outside the range specified in the present invention, it was difficult to make the resin water-based.

  Further, in Comparative Example 4, although the production method was changed, a desired aqueous dispersion was not obtained. Even when the final charge amount was the same, it was confirmed that the dispersion did not proceed efficiently when all the raw materials were charged at once. That is, it was found that by adopting the production method of the present invention, the aqueous dispersion was greatly advanced, and it was proved that a polyolefin resin dispersion having a fine particle diameter was obtained.

  In Reference Example 1, the resin composition and the particle diameter are almost the same as those in Example 1, and although there is no particular problem in stability as an aqueous dispersion, since the non-volatile aqueous additive is used, the water resistance of the coating film And adhesion with PP base material decreased.

Claims (4)

The olefin component consists only of the propylene component (A) and the butene component (B), the mass ratio (A / B) is in the range of 60/40 to 95/5, and the total amount of olefin components (A + B) is 100 parts by mass. An aqueous dispersion containing a polyolefin resin containing 0.5 to 15 parts by mass of an unsaturated carboxylic acid unit and an aqueous medium, wherein the weight average particle diameter of the polyolefin resin in the aqueous dispersion is 0.10 μm. less and, and state, and are dispersity of 1.5 or less according to the particle size distribution, the polyolefin resin aqueous dispersion characterized by containing substantially no non-volatile water-aid. Coatings, primers, paints, inks or adhesives comprising the polyolefin resin aqueous dispersion according to claim 1 Symbol placement. After heating and stirring a polyolefin resin, a basic compound, an organic solvent and water in a sealed container at a temperature of 80 to 240 ° C., at least one of the basic compound, the organic solvent and water is added, and the mixture is 80 to 80 in a sealed container. heating at a temperature of 240 ° C., the production method of the polyolefin resin aqueous dispersion of claim 1 Symbol mounting, characterized in that stirring. After heating and stirring a polyolefin resin, a basic compound, an organic solvent and water in a sealed container at a temperature of 80 to 240 ° C., at least one of the basic compound, the organic solvent and water is added, and the mixture is 80 to 80 in a sealed container. heating at a temperature of 240 ° C., and stirred, then, the production method of the polyolefin resin aqueous dispersion of claim 1 Symbol mounting and removing at least a portion of the organic solvent.