JP2009084477A - Polyester resin aqueous dispersion mixture, coating film formed material obtained by the same, and laminated body using the coating film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polyester resin aqueous dispersion which has low temperature adhesiveness, is softened rapidly by sensitizing heat and is solidified by cooling to attain sufficient cohesive force. <P>SOLUTION: The aqueous dispersion contains a polyester resin (A) having ≤20°C glass transition point, 2-10 mgKOH/g acid value and number average molecular weight of ≥10,000 and a polyolefin resin (B) in a ratio (A)/(B) by mass of (98/2) to (91/9). <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  INDUSTRIAL APPLICABILITY The present invention utilizes an aqueous dispersion of a heat-sensitive resin, which is particularly useful as an adhesive, in which a polyolefin resin is contained in a specific ratio in a polyester resin, and a resin film-forming product obtained therefrom and the film It is related with the laminated body.

  Polyester resins are excellent in adhesion to various substrates, and are therefore used in large quantities as film-forming resins in the fields of adhesives and coating agents.

  In the said field | area, what melt | dissolved or disperse | distributed the polyester resin in the solvent is applied to a base material, and a film | membrane is formed. In particular, the adhesive is generally used by heating the film in the subsequent steps. In such applications, it is required that the film softens quickly in response to applied heat, and solidifies by cooling to exhibit cohesive force (adhesive force) (heat-sensitive adhesiveness).

  On the other hand, from the standpoint of environmental protection in recent years, resource saving, regulations on hazardous materials under the Fire Service Act, and workplace environment improvement, as a means to make polyester resin a coating solution, from conventional organic solvent solutions to “water-based” There is an active movement to replace “water dispersion”.

  An aqueous dispersion with excellent storage stability can be obtained by using a high molecular weight polyester resin having a specific acid value and removing the organic solvent in the aqueous dispersion after phase inversion from the amphiphilic organic solvent. It has been found. However, when the glass transition point exceeds 20 ° C., there is a problem that heat-sensitive adhesiveness is poor (Patent Document 1).

Also, a method of mixing a polyester resin aqueous dispersion and a polyolefin resin aqueous dispersion at a specific ratio to form a film excellent in blocking resistance and adhesion (Patent Document 2), a polyolefin resin aqueous dispersion and a polyester resin aqueous Although a method of mixing the dispersion with a specific ratio and improving the adhesion to the vinyl chloride base material is disclosed (Patent Document 3), if the mixing ratio of the olefin resin is small, the heat sealability may be inferior. There was a problem of poor adhesion.
International Publication No. 2004037924 Pamphlet JP 2003-327756 A JP 2006-348078 A

  An object of the present invention is to provide a water dispersion of a polyester resin, which can be softened quickly in response to low temperature adhesiveness and heat, and solidified by cooling to obtain a sufficient cohesive force.

  As a result of intensive studies to solve such problems, the present inventors blend a small amount of a specific polyolefin resin aqueous dispersion with respect to a polyester resin aqueous dispersion in which a specific polyester resin is dispersed in water. Thus, the inventors have found that the above object can be achieved, and have reached the present invention.

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

[1] A polyester resin (A) having a glass transition point of 20 ° C. or less, an acid value of 2 to 10 mg KOH / g, and a number average molecular weight of 10,000 or more, and a polyolefin resin (B) are (A) / (B) = An aqueous dispersion characterized by being contained in a range of 98/2 to 91/9 (mass ratio).
[2] The aqueous dispersion according to [1], wherein the polyester resin (A) has a carboxyl group, and a part or all of the carboxyl group is neutralized with a basic compound.
[3] The aqueous dispersion of [1] or [2], wherein the polyester resin (A) contains at least an aromatic polybasic acid and an aliphatic glycol as monomer components.
[4] The aqueous dispersion according to [1] to [3], wherein the ratio of the aromatic polybasic acid to the total acid components constituting the polyester resin (A) is 40 mol% or more.
[5] The acid component constituting the polyester resin (A) is at least one selected from sebacic acid, terephthalic acid, and isophthalic acid, and the alcohol component is selected from ethylene glycol, neopentyl glycol, and 1,4-butanediol. The aqueous dispersion of [1] to [4], comprising at least one kind, wherein the polyolefin resin (B) is an ethylene-acrylic acid ester-maleic anhydride copolymer.
[6] A film formed by coating the aqueous dispersion of [1] to [5] and then removing the dispersion medium.
[7] A laminate obtained by coating the aqueous dispersion of [6] and then heat-sealing a film formed by removing the dispersion medium.

  According to the aqueous dispersion of the present invention, a resin film that exhibits low-temperature adhesiveness and strong adhesiveness can be formed. Therefore, the aqueous dispersion is suitable as an adhesive film as a binder component of a heat seal material.

  Furthermore, since a polyester resin having a relatively high molecular weight can be stably formed into an aqueous dispersion, there is no fear of water resistance deterioration due to the introduction of a hydrophilic group or an emulsifier, and the industrial utility value is extremely high.

  The aqueous resin dispersion of the present invention is a liquid material in which at least a polyester resin (A) and a polyolefin resin (B) are contained and dispersed in a dispersion medium at a specific ratio.

<Polyester resin>
In the present invention, the glass transition point of the polyester resin (A) is 20 ° C. or less. When the glass transition point is too high, the heat sensitive temperature is high and the adhesiveness is inferior.

  The acid value of the polyester resin (A) is 2 to 10 mgKOH / g, preferably 4 to 8 mgKOH / g. When the acid value is less than 2 mgKOH / g, a stable aqueous dispersion cannot be obtained. When the acid value exceeds 10 mgKOH / g, the cohesive strength of the resin film formed by drying from the aqueous dispersion decreases.

  The number average molecular weight of the polyester resin (A) is 10,000 or more, preferably 12,000 or more. When the number average molecular weight is less than 10,000, the cohesive force of the dried film forming product decreases. The molecular weight distribution is not particularly limited.

  The mass ratio of the polyester resin (A) and the polyolefin resin (B) is in the range of 98/2 to 91/9 in the ratio of (A) / (B). When the ratio of the polyester resin (A) is less than 91% or more than 98%, the adhesive force is lower than when no polyolefin resin is added.

  Polyester resin (A) is a polycondensation of one or more polybasic acid components and one or more polyhydric alcohol components, depolymerization with polybasic acid components after polycondensation, and acid condensation after polycondensation. It can be produced by a known method such as adding an anhydride. At this time, by adjusting the polybasic acid component and / or the polyhydric alcohol component and various conditions, the glass transition point, the number average molecular weight, the acid value, and the like of the resin can be controlled.

  For example, as will be described later in detail, when an aromatic dicarboxylic acid or an aliphatic dicarboxylic acid is used as the acid component, the glass transition point is lowered when the proportion of the aliphatic dicarboxylic acid in the acid component is increased. Decreasing the proportion of dicarboxylic acid increases the glass transition point.

  Further, for example, when a linear aliphatic glycol is used as the alcohol component, the glass transition point is lowered when the proportion of the component having a large molecular weight is increased.

  For example, when the usage-amount of the polybasic acid component for depolymerization is increased, the number average molecular weight of resin will become small and an acid value will become high. When the amount of the polybasic acid component is decreased, the number average molecular weight of the resin increases and the acid value decreases. At this time, when a polybasic acid component having three or more functional groups is used, the increase in acid value becomes more significant than when a bifunctional one is used.

  The polybasic acid component and polyhydric alcohol component that can be used for the production of the polyester resin (A), and preferred components and resin compositions will be described below.

  Examples of the polybasic acid include aliphatic polybasic acids, aromatic polybasic acids, and alicyclic polybasic acids. In specific compounds, examples of the aliphatic polybasic acid include saturated aliphatic acids such as oxalic acid, (anhydrous) succinic acid, adipic acid, azelaic acid, sebacic acid, dodecanedioic acid, aicosane diacid, and hydrogenated dimer acid. Dicarboxylic acid: Unsaturated aliphatic dicarboxylic acid such as fumaric acid, maleic acid, maleic anhydride, itaconic acid, itaconic anhydride, citraconic acid, citraconic anhydride, and dimer acid. Examples of the aromatic polybasic acid include aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, phthalic acid, naphthalenedicarboxylic acid, and biphenyldicarboxylic acid. Examples of the alicyclic polybasic acid include 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, 2,5-norbornene dicarboxylic acid, and anhydrous 2,5-norbornene dicarboxylic acid. Examples thereof include alicyclic dicarboxylic acids such as acid, tetrahydrophthalic acid, and tetrahydrophthalic anhydride.

  As the polybasic acid constituting the polyester resin (A), it is preferable to use an aromatic polybasic acid among the polybasic acids described above. The proportion of the aromatic polybasic acid in the total acid component constituting the polyester resin (A) is 40 mol% or more in order to improve the cohesive strength of the resin and the adhesive strength to a substrate such as a polyester film. Preferably, it is more preferably 60 mol% or more.

  Examples of the polyhydric alcohol include aliphatic glycols, alicyclic glycols, ether bond-containing glycols, and the like. In a specific compound, as the aliphatic glycol, for example, ethylene glycol, 1,2-propylene glycol, 1,3-propanediol, 1,4-butanediol, 2-methyl-1,3-propanediol, 1, Examples include 5-pentanediol, neopentyl glycol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 1,9-nonanediol, and 2-ethyl-2-butylpropanediol. Examples of the alicyclic glycol include 1,4-cyclohexanedimethanol. Examples of the ether bond-containing glycol include diethylene glycol, triethylene glycol, dipropylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, and 1 to several ethylene oxides or propylene oxides in two phenolic hydroxyl groups of bisphenols. Glycols obtained by mole addition, such as 2,2-bis (4-hydroxyethoxyphenyl) propane, can be mentioned.

  As the polyhydric alcohol constituting the polyester resin (A), among the polyhydric alcohols described above, aliphatic glycols are preferable for improving the adhesion to the substrate. Among aliphatic glycols, 1,4-butanediol, ethylene glycol, and neopentyl glycol are particularly preferable.

  As a part of the polybasic acid or polyhydric alcohol constituting the polyester resin (A), a tribasic or higher polybasic acid or polyhydric alcohol may be used. Examples of the tribasic or more polybasic acid include trimellitic acid, trimellitic anhydride, pyromellitic acid, pyromellitic anhydride, benzophenone tetracarboxylic acid, benzophenone tetracarboxylic anhydride, trimesic acid, ethylene glycol bis (anhydro) Trimellitate), glycerol tris (anhydro trimellitate), 1,2,3,4-butanetetracarboxylic acid and the like. Examples of the trifunctional or higher functional polyhydric alcohol include glycerin, trimethylolethane, trimethylolpropane, and pentaerythritol. However, the polybasic acid or polyhydric alcohol having a functionality of 3 or more should be used in a range of 5 mol% or less, further 1 mol% or less based on the total acid component or total alcohol component constituting the polyester resin. Is preferable in order to increase the molecular weight without gelation.

  As a constituent component of the polyester resin (A), hydroxycarboxylic acid such as γ-butyrolactone, ε-caprolactone, lactic acid, β-hydroxybutyric acid, and an ethylene oxide adduct of p-hydroxybenzoic acid may be used.

The polyester resin (A) preferably contains at least an aromatic polybasic acid and an aliphatic glycol as monomer components from the viewpoints of adhesion to the substrate and cohesive strength. At this time, an aliphatic polybasic acid may be contained if desired. From such a viewpoint, a more preferable combination of “aromatic polybasic acid-aliphatic polybasic acid-aliphatic glycol” is shown below.
(AC1) terephthalic acid and isophthalic acid-sebacic acid-1,4-butanediol;
(AC2) terephthalic acid and isophthalic acid-sebacic acid-ethylene glycol and neopentyl glycol.

  In such a preferable combination of the monomer components of the polyester resin (A), the content of the aromatic polybasic acid may be within the range described above as the ratio of the aromatic polybasic acid of the polyester resin (A).

<Basic compound to neutralize polyester resin>
The polyester resin (A) has a carboxyl group, and a part or all of the carboxyl group is neutralized with a basic compound in the aqueous dispersion. As a result, a carboxyl anion is generated, and the polyester resin fine particles are stably dispersed without agglomeration due to the electric repulsive force between the anions. Therefore, a polyester resin aqueous dispersion having good dispersion stability without using a surfactant. Is obtained.

  The basic compound causes a neutralization reaction with the carboxyl group in the polyester resin, and promotes aqueous formation. When the basic compound remains in the film-forming product, its performance tends to be lowered. Therefore, the basic compound in the present invention is preferably a compound that is easily volatilized by drying, and the boiling point is preferably 160 ° C. or lower. . If it exceeds 160 ° C., it will be difficult to scatter the organic amine compound from the resin coating film by drying, and the water resistance of the coating film may deteriorate. Examples of such basic compounds include ammonia and organic amine compounds.

  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, methyliminobispropylamine, 3-methoxypropylamine, monoethanolamine, diethanolamine, triethanolamine, morpholine, N-methylmorpholine, N- Examples thereof include ethyl morpholine. Further, those which can be azeotroped with water are particularly preferred. Of these, ammonia and triethylamine are most preferable. The basic compound can be used as a single substance or as a mixture of plural substances.

  The basic compound is used according to the amount of the carboxyl group contained in the polyester resin, and may be at least an amount capable of partially neutralizing this, and is 0.6 to 15 times equivalent to the carboxyl group. Is preferable, and 0.8 to 6 times equivalent is more preferable. If it is less than 0.6 times equivalent, the effect of adding a basic compound may not be recognized. On the other hand, if it exceeds 15 times equivalent, the storage stability of the polyester resin aqueous dispersion may be deteriorated.

<Method for producing polyester resin aqueous dispersion>
The method for producing an aqueous dispersion of the polyester resin (A) of the present invention is exemplified, that is, a stable aqueous dispersion can be obtained through the following steps. The step of charging the polyester resin (A) into an amphiphilic organic solvent and heating to make a solution (Step 1), the step of mixing the solution with a basic compound and water to make an emulsion (Step 2), It is a method including a step (Step 3) of distilling off the organic solvent from the emulsion.

(Process 1)
A solution is obtained by dissolving the polyester resin (A) in an amphiphilic organic solvent. The amphiphilic organic solvent is hydrophilic and itself has an azeotropic action with water, and preferably has a boiling point of 150 ° C. or lower selected from alcohol, ketone, ether and glycol derivatives. It preferably has a boiling point of 110 ° C. or lower.

  Examples of amphiphilic organic solvents that can be used in the present invention include acetone, MEK, MIBK, dioxane, tetrahydrofuran, cyclohexanone alone, acetone / ethylene glycol monobutyl ether mixed solution, MEK / ethylene glycol monobutyl ether mixed solution, MIBK / ethylene. Glycol monobutyl ether mixed solution, dioxane / ethylene glycol monobutyl ether mixed solution, tetrahydrofuran / ethylene glycol monobutyl ether mixed solution, cyclohexanone / ethylene glycol monobutyl ether mixed solution, acetone / isopropanol mixed solution, MEK / isopropanol mixed solution, MIBK / isopropanol mixed solution , Dioxane / isopropanol mixed solution, tetrahydrofuran / isopropano Le mixed solution, cyclohexanone / isopropanol mixture solution or the like can be suitably used. Those that can be dissolved in as high a concentration as possible are preferred.

  The method for dissolving the polyester resin (A) in the above-mentioned amphiphilic organic solvent is not particularly limited, and a normal method such as heating or stirring as appropriate may be used.

(Process 2)
Next, phase inversion emulsification is performed by mixing the amphiphilic organic solvent solution of the polyester resin (A), water, and the basic compound. At this time, the order of mixing is not particularly limited. For example, the solution may be stirred, and a mixed solution of water and a basic compound may be added little by little, or after the basic compound is added. Water may be added.

(Process 3)
After emulsification, the amphiphilic organic solvent is distilled off from the viewpoint of the storage stability of the aqueous dispersion. The amphiphilic organic solvent can be distilled out of the system by azeotroping with water. The degree of distillation may be appropriately determined from the viewpoint of desired performance and stability, but the amphiphilic organic solvent should be distilled to 0.5% by mass or less of the entire polyester resin (A) aqueous dispersion. Can do. The organic solvent content can be quantified by gas chromatography.

  In this invention, it is preferable to perform the process 2 in the temperature range below 40 degreeC, and when it is 40 degreeC or more, a polyester resin (A) may raise | generate aggregation.

  The temperature condition in step 3 is not particularly limited, but it is preferably set to a temperature equal to or higher than the temperature at which the amphiphilic organic solvent and water azeotrope. If the removal of the amphiphilic organic solvent proceeds, the system eventually reaches the boiling point of water. At this time, when a high temperature is not preferable for the polyester resin (A), the boiling point may be lowered by performing under reduced pressure. After the completion of step 3, it is preferable to quickly cool to 40 ° C. or lower.

  In order to carry out each of the above steps, no special equipment is required. There should be a condenser equipped with a tank into which liquid can be introduced, the dispersion medium introduced into the tank and the polyester resin can be appropriately stirred, and the vapor to be collected can be condensed. An apparatus capable of heating to the boiling point of the organic solvent or the boiling point of water, whichever is higher, is preferable. The stirring method and the rotation speed of stirring are not particularly limited.

  In the production process of the aqueous dispersion of the polyester resin (A), filtration or the like may be performed as necessary for the purpose of preventing the coarse particles from being mixed into the aqueous dispersion. For example, a stainless steel filter of about 300 to 600 mesh may be used. Further, pressure filtration may be performed at an air pressure of about 0.2 MPa.

  The dispersion medium in which the polyester resin (A) is dispersed is an aqueous medium and is a medium composed of a liquid containing water as a main component, and may contain the organic solvent described above.

  The content of the organic solvent in the aqueous polyester resin dispersion of the present invention is not particularly limited as long as the aqueous polyester resin dispersion is stabilized. It is preferable that In addition, for the purpose of suppressing generation of repellency and bubbles during coating, an organic solvent may be added within a range that does not adversely affect performance. Moreover, after distilling a dispersion medium more than desired solid content concentration, you may dilute with water and adjust solid content concentration.

  In the present invention, when the organic amphiphilic organic solvent is distilled off, the pH may be lowered to around 6. The pH of the polyester resin (A) aqueous dispersion is preferably 6.6 or more. It is preferable to adjust the pH by adding a basic compound to the polyester resin aqueous dispersion after Step 3 of the production method. It is more preferable that the pH is 8.5 or more because the generation of bacteria and sputum is suppressed. When the pH of the aqueous dispersion is smaller than 6.6, the stability of the aqueous dispersion tends to be inferior and the antibacterial effect is small. On the other hand, the upper limit of the pH is not particularly limited, but when it is larger than 12.0, the molecular weight of the polyester resin (A) may be lowered over time, and is preferably 12.0 or less. As the basic compound for adjusting the pH, ammonia and amine used in Step 2 are used.

<Characteristics of polyester resin (A) aqueous dispersion>
The viscosity of the aqueous dispersion of the present invention is not particularly limited. For example, in the case of application to a base material, the viscosity is preferably in the range of 1 to 100 mPa · s. Further, the volume average particle diameter of the aqueous dispersion is not particularly limited, but is preferably 400 nm or less because it is stable, and more preferably 300 nm or less.

<Polyolefin resin>
The polyolefin resin (B) is a resin mainly composed of an olefin component (B2) such as olefins having 2 to 6 carbon atoms such as ethylene, propylene, isobutylene, 1-butene, 1-pentene and 1-hexene. A mixture of these monomers may be used. Among these, olefins having 2 to 4 carbon atoms such as ethylene, propylene, isobutylene and 1-butene are more preferable, and ethylene is particularly preferable.

  The polyolefin resin (B) preferably contains an unsaturated carboxylic acid (B1) for making the resin aqueous (liquefied). The unsaturated carboxylic acid (B1) is preferably contained in an amount of 0.01% by weight or more and less than 10% by weight, more preferably 0.1% by weight or more and less than 8% by weight, even more preferably. It is 0.5 mass% or more and less than 5 mass%, and 1-4 mass% is the most preferable. When the content of the component (B1) is less than 0.01% by mass, it tends to be difficult to make the resin aqueous (liquefied). On the other hand, when the content of the component (B1) is 10% by mass or more, it becomes easy to make it water-based, but water resistance may deteriorate.

  Examples of such unsaturated carboxylic acid (B1) include (meth) acrylic acid, maleic acid, itaconic acid, fumaric acid, and crotonic acid. The unsaturated carboxylic acid (B1) may be a derivative such as a salt, an acid anhydride, a half ester, and a half amide. Among these, acrylic acid, methacrylic acid, and (anhydrous) maleic acid are preferable, and acrylic acid and maleic anhydride are particularly preferable. Moreover, the copolymerization form of this component is not specifically limited, Any of random copolymerization, block copolymerization, graft copolymerization, etc. may be sufficient. Note that the acid anhydride forms an acid anhydride structure in which the adjacent carboxyl group is dehydrated and cyclized in the dry state of the resin, but in an aqueous medium containing a basic compound, part or all of the acid anhydride is ring-opened. As a result, the structure of the carboxylic acid or its salt can be easily obtained.

  Furthermore, the polyolefin resin (B) preferably contains a (meth) acrylic acid ester component (B3) from the viewpoint of adhesiveness and heat sealability. Regarding the content of (B3), the mass ratio (B2) / (B3) of the olefin component (B2) and the (meth) acrylic ester (B3) component is the total amount of these two components being 100% by mass. It is preferably 55/45 to 99/1, and most preferably 75/25 to 95/5 in order to improve adhesiveness. When the ratio of the component (B3) is less than 1% by mass, the adhesiveness and heat sealability tend to decrease. On the other hand, when the content of the compound (B3) exceeds 45% by mass, the properties of the resin derived from the olefin component are lost, and performances such as water resistance and heat sealability are deteriorated.

  Examples of the (meth) acrylic acid ester (B3) component include methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, hexyl (meth) acrylate, octyl (meth) acrylate, Examples include lauryl (meth) acrylate. Of these, methyl (meth) acrylate, ethyl (meth) acrylate, and butyl (meth) acrylate are particularly preferable. In addition, the (meth) acrylic acid ester component may be converted to a (meth) acrylic acid component by hydrolyzing a part of the ester bond when the aqueous resin is made. In such a case, The component ratio after the change may be within a specified range.

  Specific examples of the polyolefin resin (B) include ethylene-acrylic acid ester-maleic anhydride copolymer, ethylene-propylene-maleic anhydride copolymer, ethylene-butene-maleic anhydride copolymer, propylene-butene- Maleic anhydride copolymer, ethylene-propylene-butene-maleic anhydride copolymer, ethylene-propylene-acrylic ester-maleic anhydride copolymer, ethylene-butene-acrylic ester-maleic anhydride copolymer, Propylene-butene-acrylic acid ester-maleic anhydride copolymer, ethylene-propylene-butene-acrylic acid ester-maleic anhydride copolymer, and the like. Among them, ethylene-acrylic acid ester-maleic anhydride copolymer is exemplified. Most preferred.

  In the polyolefin resin (B), monomers other than those described above may be copolymerized at 20% by mass or less of the total resin. Examples thereof include alkyl vinyl ethers having 3 to 30 carbon atoms such as methyl vinyl ether and ethyl vinyl ether, dienes, (meth) acrylonitrile, halogenated vinyls, halogenated vinylidenes, carbon monoxide, and sulfur dioxide.

  The polyolefin resin (B) preferably has a melt flow rate of 0.01 to 500 g / 10 min at 190 ° C. and a load of 2160 g, which is a measure of molecular weight, more preferably 0.1 to 400 g / 10 min, and 1 to 300 g. / 10 minutes is more preferable, and 5-200 g / 10 minutes is more preferable. When the melt flow rate of the polyolefin resin (B) is less than 0.01 g / 10 minutes, it may be difficult to make the resin water-based or heat sealability may be deteriorated. On the other hand, when the melt flow rate of the polyolefin resin (B) exceeds 500 g / 10 minutes, the resulting coating film tends to be hard and the heat sealability tends to deteriorate.

<Method for producing aqueous dispersion of polyolefin resin>
The method for producing the aqueous dispersion of the polyolefin resin (A) of the present invention is not particularly limited. For example, a method of heating and stirring the polyolefin resin and the aqueous medium in a container that can be sealed can be employed. At this time, the shape of the resin used for the aqueous treatment is not particularly limited, but it is preferable to use a granular or powdery material having a particle diameter of 1 cm or less, preferably 0.8 cm or less, from the viewpoint of increasing the aqueousization rate.

  Any container may be used as long as it is equipped with a tank into which liquid can be charged and can appropriately stir the mixture of the aqueous medium and resin charged into the tank. As such an apparatus, a known solid / liquid stirring apparatus or emulsifier can be used, and an apparatus capable of pressurization of 0.1 MPa or more is preferable. The stirring method and the rotation speed of stirring are not particularly limited.

  After each raw material is put into the tank of this apparatus, it is preferably stirred and mixed at a temperature of 40 ° C. or lower. Next, while maintaining the temperature in the tank at 50 to 200 ° C., preferably 60 to 200 ° C., the resin is sufficiently made aqueous by continuing stirring for 5 to 120 minutes, and then the temperature is lowered to 40 ° C. or less under stirring. An aqueous dispersion can be obtained by cooling. When the temperature in the tank is less than 50 ° C., it becomes difficult to make the resin water-based. When the temperature in a tank exceeds 200 degreeC, there exists a possibility that the molecular weight of resin may fall.

  In the case where the polyolefin resin (B) has an unsaturated carboxylic acid component, it is preferable to add a basic compound similar to that used when the polyester resin (A) is dispersed during aqueous formation. The addition amount of the basic compound is preferably 0.5 to 3.0 times equivalent to the carboxyl group in the polyolefin resin (1 mol of acid anhydride group is regarded as 2 mol of carboxyl group), 0.8 -2.5 times equivalent is more preferable and 1.0-2.0 times equivalent is especially preferable. If it is less than 0.5 times equivalent, the addition effect of a basic compound is not recognized, and if it exceeds 3.0 times equivalent, the drying time at the time of coating film formation may become long or the aqueous dispersion may be colored.

  In addition, when making the polyolefin resin (B) aqueous, it is preferable to add an organic solvent from the viewpoint of improving the speed of water addition and reducing the particle size of the resin particles. The addition amount of the organic solvent is preferably 1 to 40% by mass in the aqueous dispersion of polyolefin resin, more preferably 2 to 30% by mass, and particularly preferably 3 to 20% by mass. In addition, the organic solvent can be distilled out of the system by heating the aqueous dispersion with stirring at normal pressure or reduced pressure, and finally, in the aqueous dispersion of polyolefin resin. It may be 1% by mass or less.

  Specific examples of the organic solvent used include ethanol, n-propanol, isopropanol, n-butanol, methyl ethyl ketone, cyclohexanone, tetrahydrofuran, dioxane, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, and ethylene glycol monobutyl ether. From the viewpoint of drying at a lower temperature, ethanol, isopropanol, and n-propanol are particularly preferable.

  In the production process of the aqueous dispersion of the polyolefin resin (B), filtration or the like may be performed as necessary for the purpose of preventing mixing of coarse particles into the aqueous dispersion. For example, a stainless steel filter of about 300 to 600 mesh may be used. Further, pressure filtration may be performed at an air pressure of about 0.2 MPa.

<Characteristics of aqueous dispersion of polyolefin resin (B)>
The number average particle diameter of the polyolefin resin (B) particles in the aqueous dispersion is the stability of the aqueous dispersion, the surface smoothness when applied, the transparency of the coating film obtained by mixing with the polyester resin (A), From the viewpoint of performance (adhesiveness, heat sealability), the volume average particle size is preferably 500 nm or less, more preferably 300 nm or less, further preferably 200 nm or less, and particularly preferably 150 nm or less.

<Method for producing aqueous dispersion>
What is necessary is just to mix each aqueous dispersion of the polyester resin (A) obtained by the method mentioned above and polyolefin resin (B) as a manufacturing method of an aqueous adhesive. In mixing, a known liquid / liquid mixing apparatus may be used as appropriate. Since the mixing property of the aqueous polyester resin dispersion and the aqueous polyolefin resin dispersion is good, a simple mixing operation can be performed in a very short time. Moreover, after mixing, solid content concentration can also be adjusted by the method of distilling an aqueous medium or diluting with water or an organic solvent so that it may become desired solid content concentration.

<Usage of water dispersion>
After the aqueous dispersion of the present invention is coated on the substrate surface, the dispersion medium (aqueous medium) is removed to form a uniform film in close contact with the substrate surface. Specifically, since the aqueous dispersion of the present invention is excellent in film forming ability, it can be applied to various substrate surfaces by a known film forming method such as a dipping method, a brush coating method, a spray coating method, or a curtain flow coating method. A uniform resin film can be formed in close contact with various substrate surfaces by coating uniformly, setting as necessary near room temperature, and then subjecting to heat treatment for drying or drying and baking. 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, etc. In consideration of economy, the heating temperature is preferably 30 to 250 ° C., 90 ˜160 ° C. is particularly preferred, and the heating time is preferably 1 second to 20 minutes, particularly preferably 10 seconds to 5 minutes.

  When the resin film is formed using the aqueous dispersion of the present invention, the thickness is appropriately selected depending on the application, but is usually 0.01 to 100 μm, preferably 0.1 to 50 μm, most preferably 0.5 to 25 μm. If the film is formed so that the thickness of the resin film falls within the above range, a resin film having excellent uniformity can be obtained. In order to adjust the thickness of the resin film, in addition to appropriately selecting an apparatus used for coating and its use conditions, it is necessary to use an aqueous dispersion having a concentration suitable for the desired thickness of the resin film. preferable.

  Examples of the substrate on which the resin film is formed using the aqueous dispersion of the present invention include metals and polyester films, and polyester films are particularly preferable.

  The content of the resin in the aqueous dispersion of the present invention is appropriately selected depending on the intended use, the thickness of the target film, and the molding method of the film, but is usually 1 to 50% by mass, 40% by mass is preferred. When it exceeds 50% by mass, the storage stability of the aqueous dispersion may deteriorate. On the other hand, if it is less than 1% by mass, a uniform film may not be formed. The resin content is the total content of the polyester resin (A) and the polyolefin resin (B).

  The present invention will be specifically described by way of examples.

Various characteristics were measured or evaluated by the following methods.
(1) Acid value of polyester resin 0.5 g of polyester resin was dissolved in 50 ml of water / dioxane = 1/9 (volume ratio), titrated with KOH using cresol red as an indicator, and the KOH consumed for neutralization. A value obtained by converting the number of mg per 1 g of the polyester resin was determined as an acid value.
(2) Number average molecular weight of polyester resin The number average molecular weight is determined by GPC analysis (using liquid feeding unit LC-10ADvp type and UV-visible spectrophotometer SPD-6AV type manufactured by Shimadzu Corporation, solvent: tetrahydrofuran, polystyrene conversion). Asked.
(3) Glass transition point of polyester resin 10 mg of polyester resin is used as a sample, and the temperature is increased from −30 ° C. to 200 ° C. at a rate of 10 ° C./min using a DSC (Differential Scanning Calorimetry) measuring device (DSC7 manufactured by PerkinElmer). The measurement was performed and the temperature was maintained at 200 ° C. for 3 minutes, and then the temperature was decreased to −40 ° C. at a rate of 10 ° C./min. Again, in the process of raising the temperature from −30 ° C. to 200 ° C. at a rate of 10 ° C./min, the temperature of the rise of the displacement toward the endothermic side (extrapolated glass transition start temperature Tig defined in JIS K 7121) is set to glass. The transition point.
(4) Melt flow rate of polyolefin resin It measured by the method of JIS6730 description (190 degreeC, 2160g load).
(5) Solid Content Concentration of Resin Water Dispersion 1 g of the resin dispersion was weighed and heated at 150 ° C. until the mass of the residue (solid content) reached a constant weight to determine the resin solid content concentration.
(6) Viscosity of Resin Water Dispersion The rotational viscosity of the water dispersion at a temperature of 30 ° C. was measured using a DVL-BII type digital viscometer (B type viscometer) manufactured by Tokimec Corporation.
(7) Content of organic solvent in resin water dispersion Shimadzu Corporation gas chromatograph GC-8A [using FID detector, carrier gas: nitrogen, column packing material (manufactured by GL Sciences): PEG-HT (5 %)-Uniport HP (60/80 mesh), column size: 3 mm diameter × 3 m, sample charging temperature (injection temperature): 150 ° C., column temperature: 60 ° C., internal standard: n-butanol] A body or an aqueous dispersion diluted with water was directly charged into the apparatus, and the content of the organic solvent was determined. The detection limit was 0.01% by mass.
(8) pH of resin water dispersion
It was measured at 25 ° C. using a glass electrode type hydrogen concentration meter manufactured by HORIBA, Ltd. and pH METER F-21.
(9) Average particle diameter of resin particles The volume average particle diameter was determined using a Microtrac particle size distribution analyzer UPA150 (MODEL No. 9340) manufactured by Nikkiso Co., Ltd.
(10) Thickness of Resin Film Using a thickness gauge (Union Tool, MICROFINE Σ), the thickness of the base material (in the examples, polyester (PET) film (Unitika Ltd., thickness 38 μm)) is measured in advance. In addition, after forming the resin film on the base material using the aqueous dispersion, the thickness of the base material having this resin film was measured by the same method, and the difference was taken as the thickness of the resin film.
(11) Peel test A PET film (Unitika Ltd., thickness 38 μm) is coated with an aqueous dispersion using a desktop coating device (Yasuda Seiki, film applicator No. 542-AB, Meyer bar). After drying in a 120 ° C. hot air oven for 1 minute to form a 5 μm thick resin film, it is taken out to room temperature of 23 ° C. and stacked so that the coated surface and coated surface are in contact with each other, Pressure bonding was performed at 120 ° C. and a sealing pressure of 0.2 MPa for 10 seconds. This sample was measured for peel strength at a peel surface angle of 90 degrees, a peel speed of 50 mm / min, and a peel width of 25 mm in an atmosphere at 20 ° C. using a tensile tester (Intesco Precision Universal Material Tester Model 2020 manufactured by Intesco Corporation). .

[Examples of polyester resin production]
(Production example of polyester resin “P-1”)
46.5 g of terephthalic acid, 56.4 g of isophthalic acid, 76.8 g of sebacic acid, 109.8 g of 1,4-butanediol, and 0.12 g of tetra-n-butyl titanate are placed in a heat-resistant pressure glass container equipped with a stirrer. The esterification reaction was carried out by heating at 220 ° C. for 3 hours. Next, the temperature of the system was raised to 230 ° C., and the pressure of the system was gradually reduced to 13 Pa after 1 hour. After the polymerization reaction for 4 hours, the system was brought to atmospheric pressure with nitrogen gas, 1.2 g of trimellitic anhydride was added, and the mixture was stirred for 2 hours to perform a depolymerization reaction to obtain a polyester resin P-1.
(Production example of polyester resin “P-4”)
A polyester resin “P-4” was obtained using the same method as the method for producing the polyester resin “P-1” except that the raw material composition shown in Table 1 was used.
(Production example of polyester resin “P-2”)
Take 99.6 g of terephthalic acid, 16.6 g of isophthalic acid, 60.6 g of sebacic acid, 59.3 g of neopentyl glycol, and 38.4 g of ethylene glycol in a heat-resistant pressure glass container equipped with a stirrer and heat at 250 ° C. for 3 hours. Then, esterification reaction was performed. Subsequently, after adding 0.13 g of zinc acetate dihydrate as a catalyst, the temperature of the system was set to 270 ° C., and the pressure of the system was gradually reduced to 13 Pa after 1 hour. After 3 hours, the system was brought to atmospheric pressure with nitrogen gas, and when the temperature of the system was lowered to 250 ° C., 1.15 g of trimellitic anhydride was added and stirred for 2 hours to conduct a depolymerization reaction. 2 "was obtained.
(Production examples of polyester resins “P-3” and “P-5”)
Polyester resins “P-3” and “P-5” were obtained using the same method as the production method of the polyester resin “P-2” except that the raw material compositions prepared in Table 1 were used.

  The compositions of the polyester resins “P-1” to “P-5” are shown together in Table 2 together with physical properties.

[Polyolefin resin]
Table 3 summarizes the characteristic values of the polyolefin resin used in the present invention.

  The polyester resin aqueous dispersions used in Examples and Comparative Examples were produced as follows.

[Polyester resin water dispersion production example]
(Production of polyester resin aqueous dispersion “E-1”)
400 g of polyester resin “P-1” and 600 g of methyl ethyl ketone are charged into a 2 liter polyethylene container, and stirred with a stirrer (Mazela 1000, manufactured by Tokyo Rika Co., Ltd.) while heating the container with hot water of about 70 ° C. Thus, the polyester resin was completely dissolved in methyl ethyl ketone to obtain a polyester resin solution having a solid concentration of 40% by mass. Next, 500 g of the polyester resin solution was charged into a jacketed glass container (internal volume: 2 liters), and cold water was passed through the jacket to maintain the system temperature at 18 ° C., followed by stirring with a stirrer (Tokyo Rika Co., Ltd., MAZELA1000). 600 rpm). Next, 38 g of triethylamine was added as a basic compound while stirring, and subsequently 462 g of distilled water at 18 ° C. was added at a rate of 100 g / min. During addition of the whole amount of distilled water, the system temperature was always 20 ° C. or lower. After completion of the addition of distilled water, the mixture was stirred for 30 minutes to obtain an aqueous dispersion having a solid content concentration of 20% by mass. Next, 800 g of the obtained polyester resin aqueous dispersion was charged into a round bottom flask, transferred to an oil bath at 85 ° C., and methyl ethyl ketone was azeotroped with water while stirring with a condenser. The temperature of the oil bath was raised according to the distilling condition, and was finally set to 120 ° C. When 284 g was reached while measuring the mass of the distillate, heating was stopped and the mixture was cooled to room temperature with a water bath. Further, 2.1 g of 28% ammonia water was added and stirred, and then the liquid component in the flask was filtered with a 600 mesh filter (Ayatatami Weave) to obtain an aqueous polyester resin dispersion “E-1”. . The dispersion was analyzed for various physical properties. When the appearance of this aqueous dispersion was visually observed, it was uniform without precipitation, layer separation or solidification.
(Production of polyester resin aqueous dispersions “E-2”, “E-4” and “E-5”)
The polyester resin water dispersion was carried out in the same manner as in the production example of the polyester resin water dispersion “E-1” except that the polyester resins “P-2”, “P-4” and “P-5” were used. The bodies “E-2”, “E-4” and “E-5” were obtained.
(Production of polyester resin aqueous dispersion “E-3”)
558.4 g of water, 135.0 g of isopropyl alcohol, 300 g of polyester resin “P-3” and 6.4 g of 28% by mass ammonia water were placed in a 3 liter three-necked round bottom flask. Heated to 70 ° C. After 1 hour, 249.8 g of water was added to the system while heating and stirring was continued. Next, a condenser was attached to the flask, and the oil bath was set at 85 ° C. to distill isopropyl alcohol and water azeotropically. The temperature of the oil bath was raised according to the distillation status, and finally it was set to 120 ° C. When 249.8 g was reached while measuring the mass of the distillate, heating was stopped and the mixture was cooled to room temperature in a water bath. The liquid component in the flask was filtered with a 600 mesh (Ayatatami weave) filter to obtain an aqueous polyester resin dispersion “E-3”. The dispersion was analyzed for various physical properties. When the appearance of this aqueous dispersion was visually observed, it was uniform without precipitation, layer separation or solidification.

  Table 4 summarizes the evaluation results of the polyester resin aqueous dispersion alone.

  The aqueous polyolefin resin dispersions used in Examples and Comparative Examples were produced as follows.

[Example of polyolefin resin water dispersion production]
(Production of aqueous polyolefin resin dispersion “E-6”)
3. Using a stirrer equipped with a heat-resistant 1-liter glass container with a heater, 60.0 g of polyolefin resin [Bondaine HX-8210 “P-6”: manufactured by Arkema Corporation], 60.0 g of isopropanol; When 4 g (1.2 equivalents to the carboxyl group of maleic anhydride in the resin) of triethylamine and 175.6 g of distilled water were charged into a glass container and stirred at a rotation speed of 300 rpm, the bottom of the container The resin particles were not precipitated, and it was confirmed that they were 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 140 to 145 ° C. and further stirred for 20 minutes. Then, it put on the water bath and cooled to room temperature (about 25 degreeC), stirring with a rotational speed of 300 rpm. This was transferred to a 3 liter 3-neck round bottom flask and 111.0 g of water was added. Next, a condenser was attached to the flask, and the oil bath was set at 85 ° C. to distill isopropyl alcohol and water azeotropically. The temperature of the oil bath was raised according to the distillation status, and finally it was set to 120 ° C. The heating was stopped when 111.0 g was reached while measuring the mass of the distillate, and the mixture was cooled to room temperature in a water bath. Then, pressure filtration (air pressure 0.2 MPa) was performed with a 300 mesh stainless steel filter (wire diameter 0.035 mm, plain weave) to obtain a milky white uniform polyolefin resin aqueous dispersion E-6.
(Production of aqueous polyolefin resin dispersion E-7)
Using a stirrer equipped with a hermetic pressure-resistant 1-liter glass container with a heater, 60.0 g of polyolefin resin [Bondaine LX1440 “P-6”: manufactured by Arkema Corporation], 84.0 g of isopropanol, 6.6 g ( Triethylamine (1.2 times equivalent to the carboxyl group of maleic anhydride in the resin) and 149.4 g of distilled water were charged into a glass container and stirred at a stirring blade rotation speed of 300 rpm. Precipitation of the resin granular material was not recognized, and it was confirmed that it 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 140 to 145 ° C. and further stirred for 20 minutes. Then, after putting in a water bath and cooling to room temperature (about 25 ° C.) while stirring at a rotational speed of 300 rpm, pressure filtration (air pressure 0.2 MPa) with a 300 mesh stainless steel filter (wire diameter 0.035 mm, plain weave) As a result, a milky white uniform polyolefin resin aqueous dispersion E-7 was obtained.

  Table 5 summarizes the evaluation results of the polyester resin aqueous dispersion alone.

[Example 1]
Using “E-1” as the aqueous dispersion of the polyester resin (A) and “E-6” as the aqueous dispersion of the polyolefin resin (B), 95 g of “E-1” and 7.5 g of “E-6” were used at room temperature. Under stirring for about 5 minutes, an aqueous dispersion “E-8” was obtained.
[Example 2]
“E-2” is used as the polyester resin (A) aqueous dispersion, “E-6” is used as the aqueous polyolefin resin (B) dispersion, and 95 g of “E-2” and 7.5 g of “E-6” are used at room temperature. Under stirring for about 5 minutes, an aqueous dispersion “E-9” was obtained.
[Example 3]
Using “E-2” as the aqueous dispersion of the polyester resin (A) and “E-7” as the aqueous dispersion of the polyolefin resin (B), 97 g of “E-2” and 4.5 g of “E-7” were added at room temperature. Under stirring for about 5 minutes, an aqueous dispersion “E-10” was obtained.
[Example 4]
Using “E-2” as the aqueous dispersion of the polyester resin (A) and “E-7” as the aqueous dispersion of the polyolefin resin (B), 91 g of “E-2” and 13.5 g of “E-7” were used at room temperature. Under stirring for about 5 minutes, an aqueous dispersion “E-11” was obtained.
[Example 5]
“E-2” is used as the polyester resin (A) aqueous dispersion, “E-7” is used as the aqueous polyolefin resin (B) dispersion, and 95 g of “E-2” and 7.5 g of “E-7” are used at room temperature. Under stirring for about 5 minutes, an aqueous dispersion “E-12” was obtained.
[Example 6]
Using “E-4” as the polyester resin (A) aqueous dispersion and “E-6” as the polyolefin resin (B) aqueous dispersion, 93 g of “E-4” and 10.5 g of “E-6” were used at room temperature. Under stirring for about 5 minutes, an aqueous dispersion “E-13” was obtained.
[Example 7]
Using “E-5” as the polyester resin (A) aqueous dispersion and “E-7” as the polyolefin resin (B) aqueous dispersion, 93 g of “E-5” and 10.5 g of “E-7” Was stirred and mixed at room temperature for about 5 minutes to obtain an aqueous dispersion “E-14”.
[Comparative Example 1]
The polyester resin (A) aqueous dispersion was not mixed and “E-1” was used alone.
[Comparative Example 2]
The polyester resin (A) aqueous dispersion was not mixed and “E-2” was used alone.
[Comparative Example 3]
The polyester resin (B) aqueous dispersion was not mixed and “E-3” was used alone.
[Comparative Example 4]
The polyester resin (A) aqueous dispersion was not mixed and “E-4” was used alone.
[Comparative Example 5]
The polyester resin (A) aqueous dispersion was not mixed and “E-5” was used alone.
[Comparative Example 6]
“E-7” alone was used without mixing the polyolefin resin (B) aqueous dispersion.
[Comparative Example 7]
“E-1” is used as the polyester resin (A) aqueous dispersion and “E-6” is used as the aqueous polyolefin resin (B) dispersion. 90 g of “E-1” and 15 g of “E-6” are used at room temperature. The mixture was stirred and mixed for about 5 minutes to obtain an aqueous dispersion “E-15”.
[Comparative Example 8]
Using “E-2” as the aqueous dispersion of the polyester resin (A) and “E-7” as the aqueous dispersion of the polyolefin resin (B), 99 g of “E-2” and 1.5 g of “E-7” were used at room temperature. Under stirring for about 5 minutes, an aqueous dispersion “E-16” was obtained.
[Comparative Example 9]
Using “E-2” as the aqueous dispersion of the polyester resin (A) and “E-6” as the aqueous dispersion of the polyolefin resin (B), 90 g of “E-2” and 15 g of “E-6” at room temperature. The mixture was stirred and mixed for about 5 minutes to obtain an aqueous polyester resin dispersion “E-17”.

  Table 6 summarizes the performance of the polyester resin aqueous dispersions obtained in Examples and Comparative Examples and the evaluation results of the films obtained therefrom.

In addition, the blend effect of polyester resin (A) / polyolefin resin (B) is the peel strength of [polyester resin (A) / polyolefin resin (B)] for each of polyester resin aqueous dispersions E-1 to E-5. And the ratio of the peel strength of [polyester resin (A)],
Peel strength after blending / Peel strength before blending ≧ 1.10.
Was judged to be effective.
For example, for polyester resin water dispersion E-1, the effect of blending polyolefin resin water dispersion E-6 is calculated by (E-1 / E-6 blend peel strength) / (E-1 peel strength). Went.

  In Examples 1-7, compared with Comparative Examples 1, 2, 4, and 5, it has increased rather than the adhesive force when a polyester resin (A) is used independently.

  On the other hand, in Comparative Examples 3 and 6, there is a problem that adhesiveness does not appear.

In Comparative Examples 7, 8, and 9, the polyester resin (A) and the polyolefin resin (B) were used out of the range of (A) / (B) = 98/2 to 91/9 (mass ratio). In some cases, the adhesive strength is lower than when the polyester resin (A) is used alone, or no effect is observed.

Claims (7)

  A polyester resin (A) having a glass transition point of 20 ° C. or less, an acid value of 2 to 10 mg KOH / g, and a number average molecular weight of 10,000 or more, and a polyolefin resin (B) are (A) / (B) = 98/2. It is contained in the range of -91/9 (mass ratio), The water dispersion characterized by the above-mentioned.   The aqueous dispersion according to claim 1, wherein the polyester resin (A) has a carboxyl group, and a part or all of the carboxyl group is neutralized with a basic compound.   The aqueous dispersion according to claim 1 or 2, wherein the polyester resin (A) contains at least an aromatic polybasic acid and an aliphatic glycol as monomer components.   The aqueous dispersion according to any one of claims 1 to 3, wherein the ratio of the aromatic polybasic acid to the total acid components constituting the polyester resin (A) is 40 mol% or more.   It consists of one or more selected from sebacic acid, terephthalic acid and isophthalic acid as the acid component constituting the polyester resin (A), and one or more selected from ethylene glycol, neopentyl glycol and 1,4-butanediol as the alcohol component The aqueous dispersion according to claim 1, wherein the polyolefin resin (B) is an ethylene-acrylic ester-maleic anhydride copolymer.   A film formed by coating the aqueous dispersion according to any one of claims 1 to 5 and then removing the dispersion medium. A laminate obtained by coating the aqueous dispersion according to claim 6 and then heat-sealing a film formed by removing the dispersion medium.