JP2008056877A - Method for manufacturing polyolefin resin aqueous dispersion - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a polyolefin resin aqueous dispersion capable of dispersing a polyolefin resin in an aqueous medium finely and stably, without using a nonvolatile compound such as a surfactant. <P>SOLUTION: The method for manufacturing a polyolefin resin aqueous dispersion without substantially using a surfactant includes a step of reacting a nonchlorinated acid-modified polyolefin resin dissolved in a water-soluble organic solvent with a basic compound to neutralize an acid group in the resin and a step of adding water to the resin. The method further includes a step of heating the resin at 50-250°C after the step of adding water thereto. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for producing an aqueous dispersion of a non-chlorine acid-modified polyolefin resin.

Polyolefin resins such as propylene resin are used in large quantities mainly in automobiles, electricity, packaging, and household goods because of their excellent electrical, mechanical, chemical, shaping, hygienic, and recyclability properties. ing. However, since polyolefin resins usually do not contain polar groups in the molecular chain, there is a problem that coating and adhesion are difficult.
For this reason, a method using a resin mainly composed of a chlorinated polyolefin resin has been proposed for coating or adhesion of a polyolefin resin such as a propylene resin. However, since chlorinated resins generate harmful substances such as acidic gas during incineration, interest in the environment has increased in recent years and there has been a strong demand for a shift to non-chlorine materials.
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 coating or adhesion, it is necessary to liquefy the resin. For example, a) a method in which the resin is melted, and b) a method in which the resin is dissolved or dispersed in an organic solvent. And c) a method in which a resin is dispersed in an aqueous medium. However, in the method a), the use is limited, and it is difficult to reduce the thickness in consideration of the melt viscosity of the resin. And when the methods of b) and c) are compared, the use of organic solvents tends to be restricted from the standpoints of environmental protection, resource saving, regulation of dangerous goods by the Fire Service Act, and improvement of the workplace environment. A method is desired.

  From the background as described above, studies on making the modified polyolefin resin aqueous have been actively conducted. For example, Patent Documents 1 to 3 and the like describe that various surfactants are used as essential components in order to stably disperse the modified polyolefin resin in an aqueous medium. However, the surfactant is non-volatile and remains in the coating film of the modified polyolefin resin even after drying. The remaining surfactant, when used in a large amount, significantly reduces the water resistance of the coating, and even a small amount can dramatically change the interface properties to improve performance such as adhesion to the substrate. Adversely affect. Furthermore, since the surfactant may bleed out from the coating film, it is not preferable in terms of environment and hygiene, and performance such as adhesion to the substrate may change over time. is there.

Therefore, Patent Documents 4 and 5 report that a modified polyolefin resin is made into an aqueous dispersion without adding a non-volatile compound such as a surfactant. However, in patent document 4, since the process at a comparatively high temperature is required in order to disperse | distribute resin, there existed a problem that an apparatus and prescription were limited. Further, Patent Document 5 describes a method of emulsifying a chlorinated polyolefin resin using an ether solvent. However, since this method uses a chlorinated polyolefin resin, the environmental aspects described above are used. There was a problem.
JP-A-8-3376 JP-A-8-92427 Japanese Patent No. 2895574 International Publication No. 02/055598 Pamphlet Japanese Patent Laid-Open No. 2004-18659

  An object of the present invention is to solve the above-mentioned problems in producing an aqueous dispersion of a non-chlorinated polyolefin resin, and to use the polyolefin resin in an aqueous medium without using a non-volatile compound such as a surfactant. An object of the present invention is to provide a production method capable of finely and stably dispersing.

  As a result of intensive studies, the present inventors dissolved non-chlorine acid-modified polyolefin resin in a water-soluble organic solvent, neutralized acid groups in the resin with a basic compound, and added water, The present inventors have found that the problem can be solved and have reached the present invention.

That is, the gist of the present invention is as follows.
(1) A surface activity characterized in that a basic compound is allowed to act on a non-chlorine acid-modified polyolefin resin dissolved in a water-soluble organic solvent to neutralize the acid groups in the resin and then add water. The manufacturing method of the polyolefin resin aqueous dispersion which does not use an agent substantially.
(2) The method for producing an aqueous polyolefin resin dispersion as described in (1), wherein water is added to heat at 50 to 250 ° C.
(3) The method for producing an aqueous polyolefin resin dispersion according to (1), wherein the water-soluble organic solvent is removed after adding water.
(4) The method for producing an aqueous polyolefin resin dispersion according to (2), wherein the water-soluble organic solvent is removed after heating.

  According to the present invention, a polyolefin resin can be finely and stably dispersed in an aqueous medium without using a non-volatile compound such as a surfactant by a simple method.

The present invention will be described in detail below.
The method for producing an aqueous dispersion of polyolefin resin of the present invention is to neutralize acid groups in a resin by allowing a basic compound to act on a non-chlorine acid-modified polyolefin resin dissolved in a water-soluble organic solvent, and then adding water. And preferably a step of heating to 50 to 250 ° C. after adding water, and the surfactant is not substantially used. Furthermore, it is preferable that the process of removing a water-soluble organic solvent is included.

Examples of the acid group of the non-chlorine acid-modified polyolefin resin used in the present invention include a carboxyl group, a sulfonic acid group, a sulfuric acid group, and a phosphoric acid group. Among them, a carboxyl group is preferable because it is easily available in terms of production. .
A method for introducing a carboxyl group is not particularly limited, but a method for introducing a carboxyl group with an unsaturated carboxylic acid component is simple and preferable. The content of the unsaturated carboxylic acid component is preferably 0.1 to 20% by mass, more preferably 0.2 to 10% by mass, further preferably 0.3 to 8% by mass, and 0.5 to 6% by mass. Particularly preferred. When the unsaturated carboxylic acid unit is less than 0.1% by mass, it becomes difficult to make the adhesive aqueous (liquefaction). On the other hand, if it exceeds 20% by mass, it becomes easy to make it water-based, but the coating film properties such as alkali resistance deteriorate.

The unsaturated carboxylic acid component is a compound having at least one carboxyl group or acid anhydride group in the molecule (in the monomer unit), specifically, acrylic acid, methacrylic acid, maleic acid, maleic anhydride. In addition to itaconic acid, itaconic anhydride, fumaric acid, crotonic acid, and the like, unsaturated dicarboxylic acid half esters, half amides and the like can be mentioned. Of these, acrylic acid, methacrylic acid, maleic acid, and maleic anhydride are preferable, and acrylic acid and maleic anhydride are particularly preferable.
Moreover, the unsaturated carboxylic acid unit should just be copolymerized in polyolefin resin, The form is not limited, For example, random copolymerization, block copolymerization, graft copolymerization etc. are mentioned.
When an acid anhydride is introduced, an acid anhydride structure is formed in which the adjacent carboxyl group is dehydrated and cyclized in the dry state of the resin, but in particular in a medium containing a basic compound, a part of the acid anhydride structure is formed. Or all ring-opened to take the structure of a carboxylic acid or a salt thereof.

The olefin component (unsaturated hydrocarbon compound component) that is the main component of the acid-modified polyolefin resin may be a linear hydrocarbon, a branched hydrocarbon, or a cyclic hydrocarbon. Ethylene, propylene, isobutylene, 1-butene , 1-pentene, 1-hexene, 1-octene, 4-methyl-1-pentene, norbornene, cyclopentadiene, vinylcyclohexane, β-pinene derivatives, etc., among which olefin compounds having 2 to 6 carbon atoms are resins. From the viewpoint of easy availability, ethylene, propylene, and 1-butene are preferable among these.
The content of the olefin component is not a polyolefin resin unless it is 50% by mass or more of the resin component, and is preferably 60% by mass or more, and 70% by mass from the viewpoint of the coating properties of the polyolefin resin and the adhesion to the polyolefin material. The above is more preferable, and 80% by mass or more is particularly preferable.

The constituent components of the acid-modified polyolefin resin excluding the unsaturated carboxylic acid component and the olefin component are not particularly limited. For example, dienes such as butadiene and isoprene, (meth) acrylic acid ester, dimethyl maleate, diethyl maleate, Maleic esters such as dibutyl maleate, (meth) acrylic amides, alkyl vinyl ethers such as methyl vinyl ether and ethyl vinyl ether, vinyl formate, vinyl acetate, vinyl propionate, vinyl pivalate, vinyl versatate, etc. Vinyl alcohol obtained by saponifying esters and vinyl esters with basic compounds, 2-hydroxyethyl acrylate, glycidyl (meth) acrylate, (meth) acrylonitrile, styrene, substituted styrene, carbon monoxide Sulfur, and the like dioxide, may be a mixture thereof.
These components only have to be copolymerized in the polyolefin resin, and the form thereof is not limited, and examples thereof include random copolymerization, block copolymerization, and graft copolymerization. Furthermore, the polyolefin resin of the present invention may be modified, and examples of the modification include known methods such as epoxidation, hydrosilation, and crosslinking.

  The weight average molecular weight of the polyolefin resin is preferably 10,000 to 200,000, more preferably 20,000 to 150,000, still more preferably 20,000 to 100,000, and particularly preferably 30,000 to 90,000. When the weight average molecular weight is less than 10,000, the cohesive force of the resin is weakened and the coating film performance such as adhesiveness may be inferior. On the other hand, if the weight average molecular weight exceeds 200,000, the dissolved state may be poor and dispersion in water may not be possible. The weight average molecular weight is a value obtained from a standard polystyrene calibration curve by gel permeation chromatography (GPC).

  In the method for producing an aqueous dispersion of the present invention, first, the polyolefin resin is dissolved in a water-soluble organic solvent. At that time, heating is preferable because it can be dissolved quickly and uniformly. 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, 1,000 rpm or more) is not essential, and an aqueous dispersion can be produced with a simple apparatus.

As the water-soluble organic solvent, those having a solubility in water at 20 ° C. of 50 g / L or more are preferably used, more preferably 100 g / L or more, and particularly preferably 200 g / L or more.
As the water-soluble organic solvent, those having a boiling point of 250 ° C. or lower are preferable, and those having a temperature of 50 to 200 ° C. are particularly preferable from the viewpoint of easy removal from the coating film. Water-soluble organic solvents having a boiling point exceeding 250 ° C. are difficult to disperse from the resin coating film by drying, and the water resistance of the coating film at low temperature drying, adhesion to the substrate, etc. may be deteriorated. .
Specific examples of the water-soluble organic solvent used include, for example, methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, sec-butanol, tert-butanol, n-amyl alcohol, isoamyl alcohol, sec- Alcohols such as amyl alcohol, tert-amyl alcohol, 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, acetic acid-n-propyl, isopropyl acetate, acetic acid-n-butyl, isobutyl acetate, acetic acid-sec-butyl, acetic acid-3-methoxybutyl, Esters such as methyl lopionate, ethyl propionate, diethyl carbonate, dimethyl carbonate, glycol derivatives such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, ethylene glycol ethyl ether acetate, Furthermore, 1-methoxy-2-propanol, 1-ethoxy-2-propanol, 3-methoxy-3-methyl-1-butanol, methoxybutanol, acetonitrile, dimethylformamide, dimethylacetamide, diacetone alcohol, ethyl acetoacetate, 1,2-dimethylglycerol, 1,3-dimethylglycerol, trimethylglycerol, etc. are mentioned.
These water-soluble organic solvents may be used as a mixture of two or more. Among these, ketones, ethers, and esters are preferable because the resin is easily dissolved.

  The solid content concentration of the polyolefin resin in the resin solution is preferably 1 to 70% by mass, more preferably 5 to 50% by mass, further preferably 10 to 40% by mass, particularly 10 to 35% by mass from the viewpoint of workability. preferable.

  Next, in the method for producing an aqueous dispersion of the present invention, a basic compound is allowed to act on the acid group in the polyolefin resin to neutralize at least a part thereof. By making the basic compound act, acid groups such as carboxyl groups and acid anhydride groups of the polyolefin resin are anionized, and the electrostatic repulsion of the anion prevents aggregation between the resin fine particles in the aqueous medium. Decentralization is achieved.

Examples of the method of allowing the basic compound to act include 1) a method of adding together with a water-soluble organic solvent when the resin is dissolved, 2) a method of adding after the resin is dissolved, and 3) a method of adding as an aqueous solution after the resin is dissolved. .
The addition amount of the basic compound is preferably 0.3 to 3 times equivalent to the acid group in the polyolefin resin (1 mol of acid anhydride group is regarded as 2 mol of carboxyl group), 0.5 to 2 A double equivalent is more preferable, and a 0.6 to 1.5-fold equivalent is particularly preferable. If the amount is less than 0.3 times equivalent, the addition effect of the basic compound is not recognized, and if the amount exceeds 3 times equivalent, the problem of the odor of the dispersion and the problem of increasing the drying time when forming a coating film, an adhesive layer, etc. There is.

Examples of such a basic compound include sodium hydroxide, potassium hydroxide, organic amine, ammonia, and the like. Although not particularly limited, ammonia or an organic amine compound that volatilizes at the time of coating film formation is water resistance of the coating film, From the viewpoint of adhesiveness, an organic amine compound having a boiling point of 30 to 250 ° C, more preferably 50 to 200 ° C is preferable. When the boiling point is less than 30 ° C., the rate of volatilization when the resin described later becomes aqueous may increase, and the aqueous formation may not proceed completely. When the boiling point exceeds 250 ° C., it becomes difficult to disperse the organic amine compound from the resin coating film by drying, and the water resistance and adhesiveness of the coating film may deteriorate.
Specific examples of the organic amine compound include triethylamine, N, N-dimethylethanolamine, aminoethanolamine, N-methyl-N, N-diethanolamine, isopropylamine, iminobispropylamine, ethylamine, diethylamine, and 3-ethoxypropylamine. , 3-diethylaminopropylamine, sec-butylamine, propylamine, methylaminopropylamine, 3-methoxypropylamine, monoethanolamine, morpholine, N-methylmorpholine, N-ethylmorpholine and the like.

  Furthermore, in the method for producing an aqueous dispersion of the present invention, water is added to a water-soluble organic solvent solution of a neutralized polyolefin resin to form a W / O type dispersion, and then water is added. This is phase-shifted to O / W type. The temperature of the water to be added is not particularly limited, but is usually 10 to 90 ° C, and preferably 30 to 70 ° C. Further, the addition rate of water is not particularly limited, but may be appropriately adjusted while observing the state in the system (the state of resin aggregation or precipitation). Further, the amount of water to be added is not particularly limited, but the final solid content of the resin is 1 to 50% by mass, preferably 5 to 40% by mass, and more preferably 5 to 30% by mass. That's fine.

  By the method for producing an aqueous dispersion of the present invention described above, the polyolefin resin can be stably dispersed to a number average particle diameter of 1 μm or less without substantially using a surfactant. The number average particle diameter of the polyolefin resin particles in the aqueous dispersion is more preferably 0.5 μm or less, and preferably 0.3 μm or less from the viewpoint of low-temperature film-forming properties and coating film smoothness from the viewpoint of improving liquid stability. More preferred is 0.2 μm or less.

The method for producing an aqueous dispersion of the present invention is characterized in that a surfactant is not substantially used, and a polyolefin resin can be stably maintained in an aqueous medium with a number average particle diameter of 1 μm or less without using a surfactant. Can do. The surfactant remains in the polyolefin resin even after the coating film is formed, and plasticizes the coating film, thereby deteriorating the properties of the polyolefin resin, such as water resistance. Since the aqueous dispersion obtained by the production method of the present invention does not substantially contain a surfactant, the coating film properties, particularly water resistance and adhesiveness are excellent.
Here, the “surfactant” is a drug or compound added for the purpose of promoting aqueous formation or stabilizing the aqueous dispersion in the production of an aqueous dispersion as described later.
“Substantially no surfactant” means that surfactants are not actively added to the system and consequently are not used. Such a surfactant is particularly preferably zero in content, but may be contained in an amount of less than 0.5% by mass with respect to the polyolefin resin component as long as the effects of the present invention are not impaired.
The surfactant component in the present invention is a compound having a molecular weight of 300 or more, dissolved in water, and contributing to dispersion and stabilization of the resin. A cationic surfactant, an anionic surfactant, Nonionic (nonionic) surfactants, amphoteric surfactants, fluorosurfactants, reactive surfactants, water-soluble polymers, etc. are included. In addition to those commonly used for emulsion polymerization, emulsifiers are also included. It is.
For example, anionic surfactants include sulfates of higher alcohols, higher alkyl sulfonic acids and salts thereof, alkyl benzene sulfonic acids and salts thereof, polyoxyethylene alkyl sulfate salts, polyoxyethylene alkyl phenyl ether sulfate salts, vinyl sulfone salts. Examples include succinate.
Nonionic surfactants 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 copolymer, etc. And sorbitan derivatives such as polyoxyethylene sorbitan fatty acid esters.
Examples of amphoteric surfactants include lauryl betaine and lauryl dimethylamine oxide.
Examples of reactive surfactants include alkylpropenylphenol polyethylene oxide adducts and their sulfate esters, allyl alkylphenol polyethylene oxide adducts and their sulfate esters, allyl dialkylphenol polyethylene oxide adducts and their sulfate esters, etc. Examples thereof include compounds having a reactive double bond.
Examples of the water-soluble polymer include polyvinyl alcohol, carboxyl group-modified polyvinyl alcohol, carboxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, modified starch, polyvinyl pyrrolidone, polyacrylic acid and salts thereof.

  In the method for producing an aqueous dispersion of the present invention, it is further preferable from the viewpoint of finer and uniform particles to heat and stir the obtained aqueous dispersion at 40 to 250 ° C. By adding this step, the aggregates and precipitates generated when water is added are refined and homogenized, and a good aqueous dispersion is obtained. Unnecessary substances such as undispersed matter are filtered from the aqueous dispersion. Filterability is greatly improved. Therefore, productivity is improved. When heating, it may be an open system or under reflux, but it is preferably carried out under pressure and in a closed system from the viewpoint of raising the temperature above the boiling point. The heating temperature is more preferably 60 to 200 ° C, further preferably 80 to 190 ° C, particularly preferably 100 to 180 ° C. When the temperature is less than 40 ° C., the effect of heating is small, and when it exceeds 250 ° C., the molecular weight of the polyolefin resin may decrease. The heating and stirring time is preferably 0.1 to 24 hours, more preferably 0.2 to 5 hours. If it is less than 0.1 hour, the effect of heating is small, and if it exceeds 24 hours, the molecular weight of the polyolefin resin may decrease. As a heating method in the tank, heating from the outside of the tank is preferable. For example, the tank can be heated using oil or water, or a heater can be attached to the tank for heating.

In the method for producing an aqueous dispersion of the present invention, a part of the water-soluble organic solvent contained therein is stripped from the obtained aqueous dispersion including the aqueous dispersion after heating and stirring. It is preferable to distill out of the system by a solvent removal operation called. By this operation, the amount of the water-soluble organic solvent in the aqueous dispersion may be appropriately reduced within the above range, may be 10% by mass or less, and is preferably 3% by mass or less, If it is 1 mass% or less, it is more preferable. Distilling off the water-soluble organic solvent by stripping requires measures in the production process such as increasing the pressure reduction of the equipment or extending the operation time. Is about 0.01% by mass (the detection limit of the analytical instrument used for the measurement of the present invention). However, even if it is less than 0.01% by mass, the performance as an aqueous dispersion is not particularly problematic. Even if the amount of the water-soluble organic solvent is reduced by stripping, the aqueous dispersion obtained by the production method of the present invention is not particularly affected in terms of performance and can be used favorably for various applications.
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. The organic solvent content can be quantified by gas chromatography. 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 is added to the aqueous dispersion in advance. You can also.

  The resin content of the aqueous dispersion obtained by the production method of the present invention is appropriately adjusted depending on the film forming conditions, the thickness and performance of the target resin layer, and is not particularly limited. It is preferably 1 to 50% by mass, more preferably 3 to 50% by mass, still more preferably 5 to 45% by mass, and particularly preferably 5 to 40% by mass in terms of maintaining an appropriate amount and exhibiting good primer layer forming ability. preferable.

  The aqueous dispersion obtained by the production method of the present invention may be used as it is. However, in order to improve various coating film performances, other heavy agents such as an isocyanate compound and an epoxy compound, and acrylic and urethane are used. An aqueous dispersion of coalescence, tackifying components such as rosins and terpenes, and the like can be added.

  Depending on the intended use, a pigment or a dye may be added to the aqueous dispersion obtained by the production method of the present invention, or an aqueous dispersion may be added to a commercially available paint or ink. The pigment or dye to be used is not particularly limited, and a commonly used pigment or dye may be appropriately selected depending on the type of paint or ink. Furthermore, various agents such as a leveling agent, an antifoaming agent, an anti-waxing agent, a pigment dispersant, and an ultraviolet absorber can be added to the aqueous dispersion as necessary. It is also possible to add organic or inorganic compounds other than those described above as long as the storage stability of the aqueous dispersion is not impaired.

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

Various characteristics were measured or evaluated by the following methods.
1. Characteristics of polyolefin resin (1) Configuration
^It calculated | required from < ¹ > H-NMR analysis (The product made by Varian, 300MHz). The polyolefin resin was measured at 120 ° C. using orthodichlorobenzene (d ₄ ) as a solvent.
(2) Weight average molecular weight Using GPC analysis (HLC-8020 manufactured by Tosoh Corporation, column is TSK-GEL), the sample was dissolved in tetrahydrofuran, measured at 40 ° C., and the number average from a calibration curve prepared with a polystyrene standard sample The molecular weight was determined.

2. Characteristics of Aqueous Polyolefin Resin Dispersion (1) Solid Concentration A suitable amount of the aqueous dispersion was weighed and heated at 150 ° C. until the mass of the residue (solid content) reached a constant weight to determine the solid content concentration.
(2) Number average particle diameter The number average particle diameter was calculated | required using the Nikkiso Co., Ltd. make and Microtrac particle size distribution analyzer UPA150 (MODEL No.9340, dynamic light scattering method). Here, the refractive index of the resin used for calculating the particle diameter was set to 1.50.
(3) Pot life The appearance when the aqueous polyolefin resin dispersion was allowed to stand 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.
(4) Filterability When 200 g of the aqueous dispersion was subjected to pressure filtration (air pressure 0.2 MPa) with a 600-mesh stainless steel filter (filtration area 130 cm ² , wire diameter 0.035 mm, plain weave), the filterability was improved depending on the filtration time. evaluated.
○: Within 10 seconds Δ: 10 to 30 seconds ×: 30 seconds or more (5) Content of water-soluble organic solvent Shimadzu Corporation gas chromatograph GC-8A [using FID detector, carrier gas: nitrogen, column packing material ( (Manufactured by GL Sciences Inc.): PEG-HT (5%)-Uniport HP (60/80 mesh), column size: diameter 3 mm × 3 m, sample charging temperature (injection temperature): 150 ° C., column temperature: 60 ° C., internal standard Substance: n-butanol], an aqueous dispersion or a solution obtained by diluting it with water was directly put into the apparatus, and the content of the water-soluble organic solvent was determined. The detection limit was 0.01% by mass.

3. Material characteristics In the following evaluation, as a base material, a biaxially stretched polyethylene terephthalate film (Embret PET12 manufactured by Unitika, thickness 12 μm, hereinafter, PET), a biaxially stretched nylon 6 film (emblem manufactured by Unitika, thickness 15 μm, below) Ny), a stretched polypropylene film (manufactured by Tosero Co., Ltd., thickness 50 μm, hereinafter referred to as PP), and a copper plate (thickness 5 mm) were used.
(1) Water resistance evaluation method of coating film The aqueous dispersion was coated on a PET film using a Meyer bar so that the thickness of the coating layer after drying was 2 μm, and then dried at 90 ° C. for 1 minute. The obtained coated film was allowed to stand at 40 ° C. for 1 day, then immersed in warm water at 60 ° C. for 24 hours, and the state of the coating film after air drying was visually evaluated.
○: No change.
Δ: The coating film is cloudy.
X: The coating film was completely dissolved or peeled off.
(2) Method for evaluating alkali resistance of coating film A PET film was coated with an aqueous dispersion using a Meyer bar so that the thickness of the coating layer after drying was 2 μm, and then dried at 90 ° C. for 1 minute. The obtained coated film was allowed to stand at 40 ° C. for 1 day, then immersed in a 5% by mass aqueous sodium hydroxide solution at room temperature for 1 hour, and the state of the coating film after air drying was visually evaluated.
○: No change.
Δ: The coating film is cloudy.
X: The coating film was completely dissolved or peeled off.
(3) Evaluation of Adhesiveness of Substrate / Coating Layer After coating the aqueous dispersion on various substrates using a Mayer bar so that the thickness of the coating layer after drying is 2 μm, at 90 ° C. for 1 minute, Dried. The obtained laminate was allowed to stand at room temperature for 1 day, and then a cellophane tape (TF-12 manufactured by Nichiban Co., Ltd.) was attached to the surface, and the degree of peeling when the tape was peeled at a stretch was visually evaluated.
○: No peeling at all.
Δ: Partially peeled off.
X: All peeled off.

Reference Example 1 (Production of polyolefin resin P-1)
Propylene-butene-ethylene terpolymer (manufactured by Huls Japan, Bestplast 708, propylene / butene / ethylene = 64.8 / 23.9 / 11.3% by mass) 100 g, 500 g of toluene, agitator, cooling In a four-necked flask equipped with a tube and a dropping funnel, after being heated and melted in a nitrogen atmosphere, a solution of 1.0 g of dicumyl peroxide as a radical generator and a 20 g solution of heptane was maintained while maintaining the system temperature at 110 ° C. Is added dropwise over 1 hour, and 6.0 g of maleic anhydride, 10.0 g of lauryl acrylate, and 10 g of heptane of 0.5 g of dicumyl peroxide are added dropwise over 1 hour. Reacted for 1 minute. After completion of the reaction, the reaction mixture was cooled to room temperature, and then the obtained reaction product was put into a large amount of acetone to precipitate a resin. This resin was further washed several times with acetone to remove unreacted substances, and then dried under reduced pressure in a vacuum dryer to obtain polyolefin resin P-1. The properties of the obtained resin are shown in Table 1.

Reference Example 2 (Production of polyolefin resin P-2)
After heating and melting 280 g of propylene-ethylene copolymer (propylene / ethylene = 81.8 / 18.2% by mass, weight average molecular weight 85,000) in a four-necked flask under a nitrogen atmosphere, the temperature in the system was changed. While maintaining at 180 ° C., 25.0 g of maleic anhydride as an unsaturated carboxylic acid and 6.0 g of di-t-butyl peroxide as a radical generator were added over 2 hours, respectively, and then reacted for 1 hour. After completion of the reaction, the obtained reaction product was put into a large amount of acetone to precipitate a resin. This resin was further washed several times with acetone to remove unreacted maleic anhydride, and then dried under reduced pressure in a vacuum dryer to obtain polyolefin resin P-2. The properties of the obtained resin are shown in Table 1.

Example 1
Using a stirrer equipped with a heat-resistant 1-liter glass container with a heater, 48.0 g of polyolefin resin P-1, 128.0 g of tetrahydrofuran (manufactured by Wako Pure Chemical Industries, Ltd.), 4.0 g of N, N -Dimethylethanolamine (manufactured by Wako Pure Chemical Industries, Ltd.) was charged to dissolve the resin at a system temperature of 60 ° C.
After cooling to 30 ° C. by air cooling, 144 g of distilled water was added over about 5 minutes.
The system was further sealed and stirred at 110 ° C. for 1 hour.
Then, after cooling to room temperature (about 25 ° C.) while stirring with air cooling, pressure filtration (air pressure 0.2 MPa) with a 600 mesh stainless steel filter (wire diameter 0.035 mm, plain weave), polyolefin resin aqueous A dispersion was obtained. Various characteristics of the aqueous dispersion are shown in Table 2.

Example 2
48.0 g of polyolefin resin P-1, 128.0 g of tetrahydrofuran (manufactured by Wako Pure Chemical Industries, Ltd.), 4.0 g of N, N using a stirrer equipped with a hermetic pressure-resistant 1 liter glass container with a heater. -Dimethylethanolamine (manufactured by Wako Pure Chemical Industries, Ltd.) was charged to dissolve the resin at a system temperature of 60 ° C.
After cooling to 30 ° C. with air cooling, 144 g of water was added over about 5 minutes.
The system was further sealed and stirred at 110 ° C. for 1 hour.
Then, it cooled to room temperature (about 25 degreeC), stirring by air cooling.
200 g of the obtained aqueous dispersion and 38 g of distilled water were charged into a 1 L two-necked round bottom flask, a mechanical stirrer and a Liebig condenser were installed, the flask was heated in an oil bath, and the aqueous medium was distilled off. When about 110 g of the aqueous medium was distilled off, the heating was terminated and the mixture was cooled to room temperature.
After cooling, the liquid component in the flask was filtered under pressure (air pressure 0.2 MPa) with a 600 mesh stainless steel filter (wire diameter 0.035 mm, plain weave), and the solid content concentration of the filtrate was measured to find 25.4 mass. %Met. While stirring the filtrate, distilled water was added to adjust the solid content concentration to 25.0% by mass. Various characteristics of the aqueous dispersion are shown in Table 2.

Example 3
An aqueous dispersion was obtained in the same manner as in Example 2 except that the polyolefin resin P-2 was used instead of the polyolefin resin P-1. Various characteristics of the aqueous dispersion are shown in Table 2.

Example 4
An aqueous dispersion was obtained in the same manner as in Example 1 except that heating after adding water was not performed. Various characteristics of the aqueous dispersion are shown in Table 2.

Example 5
In Example 1, an aqueous dispersion was obtained by the same operation except that water was added and then stirred at 40 ° C. for 1 hour. Various characteristics of the aqueous dispersion are shown in Table 2.

By using the production method of the present invention, a non-chlorinated polyolefin resin could be made into a good aqueous dispersion without adding a surfactant (Examples 1 to 5). Moreover, it became a finer particle diameter by heating at predetermined temperature after adding water, and the filterability improved (Comparison of Examples 1 and 4, 5).
Since the aqueous dispersion produced by the method of the present invention did not contain a surfactant, it was excellent in water resistance and adhesion of the coating film.

Claims (4)

  A surfactant substantially comprising a non-chlorine acid-modified polyolefin resin dissolved in a water-soluble organic solvent is allowed to act on a basic compound to neutralize acid groups in the resin, and then water is added. Process for producing an aqueous polyolefin resin dispersion which is not used in general.   The method for producing an aqueous polyolefin resin dispersion according to claim 1, wherein the aqueous dispersion is heated to 50 to 250 ° C. after adding water.   The method for producing an aqueous polyolefin resin dispersion according to claim 1, wherein the water-soluble organic solvent is removed after adding water. The method for producing an aqueous polyolefin resin dispersion according to claim 2, wherein the water-soluble organic solvent is removed after the heating.