JP2012062414A - Aqueous dispersion, and manufacturing method and laminate thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an aqueous dispersion which can form a coating film excellent in heat resistance, and is excellent in storage stability, and a method for manufacturing the aqueous dispersion capable of manufacturing the aqueous dispersion by easy steps, and to provide a laminate excellent in heat resistance.SOLUTION: The method for manufacturing the aqueous dispersion includes: a process for preparing an antioxidant solution in which a hindered phenol antioxidant which has no hydrolysis group and whose molecular weight is 500 or more is dissolved to an organic solvent; and a process for mixing the antioxidant solution and an aqueous dispersion in which a polyolefin resin is dispersed to an aqueous medium.

Description

  The present invention relates to an aqueous dispersion, a method for producing the same, and a laminate.

  Conventionally, aqueous dispersions in which a polyolefin resin is dispersed in an aqueous medium are known, and are used in various applications such as various paints, various coating liquids, and raw materials for resin films.

On the other hand, various studies have been made on antioxidants.
For example, a technique is known in which an antioxidant emulsion is added to a vinyl chloride polymerization system for the purpose of preventing oxidation of a vinyl chloride resin (for example, see Patent Document 1).
In addition, as a technique related to emulsion polymerization of vinyl chlorides, which can automatically charge antioxidants and obtain vinyl chloride resins with improved thermal stability, powdered antioxidants are emulsifiers during polymerization of vinyl chlorides. In addition, a technique is known in which an emulsion dispersed in a fine powder form in water with a suspending agent is added to uniformly disperse the antioxidant in the resulting vinyl chloride resin (for example, Patent Document 2). reference).
Furthermore, as a method for improving the resistance of leather and artificial leather to the influence of light and / or heat, an emulsifier or dispersant, (a) a water-insoluble sterically hindered amine, (b) a water-insoluble UV absorber and / or Or a method of treating substrates (leather and faux leather) with an aqueous emulsion or dispersion containing (c) a water-insoluble antioxidant and (d) optionally other additives. For example, see Patent Document 3).

JP-A-5-310809 JP-A-6-25310 JP 7-252500 A

A coating film formed using a conventional aqueous polyolefin-based dispersion has a problem in heat resistance, such as yellowing when exposed to a high temperature (for example, 200 ° C. or higher).
As a method for improving the heat resistance of the coating film, a polyolefin aqueous dispersion is produced using a polyolefin resin kneaded with an antioxidant in advance, or an antioxidant powder is directly blended with a polyolefin dispersion. Although methods for producing polyolefin-based aqueous dispersions can be considered, these methods tend to reduce the dispersibility of the antioxidant in the polyolefin-based aqueous dispersion.
Moreover, although the emulsion containing an antioxidant is described in the above Patent Documents 1 to 3, a hindered phenol type antioxidant having no hydrolyzable group and a molecular weight of 500 or more is actively used. It is not described to make a selection. Therefore, in the polyolefin-based aqueous dispersion containing these emulsions, the antioxidant may be decomposed in the dispersion, and the storage stability may be lowered.
As described above, conventionally, even when a coating film is formed using a polyolefin-based aqueous dispersion containing an antioxidant, the effect of improving the heat resistance of the coating film may not be sufficiently obtained.

  The present invention has been made in view of the above, and can provide an aqueous dispersion capable of forming a coating film excellent in heat resistance and excellent in storage stability, and an aqueous solution capable of producing the aqueous dispersion by a simple method. It aims at providing the manufacturing method of a dispersion liquid, and providing the laminated body excellent in heat resistance, and makes it a subject to achieve this objective.

The inventor of the present invention is an aqueous dispersion obtained by mixing a solution in which a specific antioxidant is dissolved in an organic solvent and a dispersion in which a polyolefin resin is dispersed, and has excellent storage stability, and The inventors have obtained the knowledge that the heat resistance when a coating film can be remarkably improved, and completed the present invention based on this finding.
That is, specific means for achieving the above-described problem are as follows.

<1> A step of preparing an antioxidant solution by dissolving a hindered phenol-type antioxidant having no hydrolyzable group and having a molecular weight of 500 or more in an organic solvent, the antioxidant solution and an aqueous solution And a step of mixing a polyolefin-based dispersion in which a polyolefin-based resin is dispersed in a medium.

<2> Manufacture of the aqueous dispersion as described in <1> in which the said organic solvent melt | dissolves the said hindered phenol type antioxidant 0.1 mass% or more at 25 degreeC, and has a boiling point of 30 to 250 degreeC. Is the method.

<3> The method for producing an aqueous dispersion according to <1> or <2>, wherein the organic solvent contains at least one selected from a compound having at least one of nitrogen and oxygen in the structure and an aromatic compound. is there.

<4> The method for producing an aqueous dispersion according to any one of <1> to <3>, wherein the organic solvent contains at least one of N-methylpyrrolidone and acetone.

<5> The method for producing an aqueous dispersion according to any one of <1> to <4>, wherein the hindered phenol-type antioxidant is a compound represented by the following general formula (I).

[In General Formula (I), ^one of R ¹ and R ² represents a branched alkyl group having 3 to 10 carbon atoms, and the other of R ¹ and R ² is a hydrogen atom, having 1 to 10 carbon atoms. A linear alkyl group or a branched alkyl group having 3 to 10 carbon atoms is represented.
In general formula (I), R ³ and R ⁴ each independently represent a hydrogen atom, a linear alkyl group having 1 to 10 carbon atoms, or a branched alkyl group having 3 to 10 carbon atoms. ]
In general formula (I), L represents a single bond or a divalent linking group having no hydrolyzable group, A represents an n-valent linking group, and n represents 2 or 3.
A plurality of L, R ¹ , R ² , R ³ , and R ⁴ present in the general formula (I) may be the same or different from each other. ]

<6> The hindered phenol-type antioxidant is 3,3 ′, 3 ″, 5,5 ′, 5 ″ -hexa-tert-butyl-a, a ′, a ″-(mesitylene-2 , 4,6-triyl) tri-p-cresol and 1,3,5-tris (3,5-di-tert-butyl-4-hydroxybenzyl) -1,3,5-triazine-2,4,6 It is a manufacturing method of the aqueous dispersion as described in any one of <1>-<5> containing at least one of (1H, 3H, 5H) -trione.

<7> The additive amount of the hindered phenol type antioxidant is 500 mass ppm or more and 3 mass% or less with respect to the entire resin in the aqueous dispersion, according to any one of <1> to <6>. This is a method for producing an aqueous dispersion.

<8> An aqueous dispersion produced by using the method for producing an aqueous dispersion according to any one of <1> to <7>.

<9> A laminate having a substrate and a film formed using the aqueous dispersion described in <8>.

  According to the present invention, an aqueous dispersion capable of forming a coating film excellent in heat resistance and excellent in storage stability is provided, and a method for producing an aqueous dispersion capable of producing the aqueous dispersion by a simple method is provided. It is possible to provide a laminate having excellent heat resistance.

  Hereinafter, the aqueous dispersion of the present invention, the production method thereof, and the laminate using the same will be described in detail.

<Aqueous dispersion and production method thereof>
The method for producing an aqueous dispersion of the present invention comprises a step of preparing an antioxidant solution in which a hindered phenol-type antioxidant having no hydrolyzable group and having a molecular weight of 500 or more is dissolved in an organic solvent ( Hereinafter, also referred to as “antioxidant solution preparation step”) and a step of mixing the antioxidant solution and a dispersion in which a polyolefin resin is dispersed in an aqueous medium (hereinafter also referred to as “polyolefin dispersion”). (Hereinafter also referred to as “mixing step”).
The aqueous dispersion of the present invention is produced by the above-described method for producing an aqueous dispersion of the present invention.

In the present invention, a hindered phenol-type antioxidant having no hydrolyzable group and having a molecular weight of 500 or more (hereinafter also referred to as “specific hindered phenol-type antioxidant”) is used. Thereby, the heat resistance when the polyolefin-based aqueous dispersion is used as a coating film can be improved. Furthermore, since the decomposition of the antioxidant in the aqueous medium can be suppressed, the storage stability of the produced aqueous dispersion can be improved.
In the present invention, the specific hindered phenol type antioxidant is dissolved in an organic solvent to prepare an antioxidant solution, and the obtained antioxidant solution is mixed with the polyolefin dispersion. Accordingly, a method for producing a polyolefin-based aqueous dispersion using a polyolefin resin in which the specific hindered phenol-type antioxidant is kneaded in advance, or a powder of the specific hindered phenol-type antioxidant to the polyolefin-based dispersion is prepared. Compared with the method of producing a polyolefin-based aqueous dispersion by directly blending, the dispersibility of the specific hindered phenol-type antioxidant in the aqueous dispersion can be improved. Further, since it is not necessary to knead the specific hindered phenol type antioxidant into the resin, the process can be simplified. Furthermore, the present invention can also be applied to commercially available aqueous polyolefin dispersions.
As described above, according to the method for producing an aqueous dispersion of the present invention, it is possible to obtain a polyolefin-based aqueous dispersion in which the specific hindered phenol-type antioxidant is uniformly dispersed. Heat resistance when it is used as a coating film can be remarkably improved. In particular, yellowing of the coating film when exposed to high temperatures (for example, 200 ° C. or higher) can be suppressed.
Hereinafter, each step will be described.

(Antioxidant solution preparation process)
In the antioxidant solution preparation step in the present invention, a hindered phenol type antioxidant (specific hindered phenol type antioxidant) having a hydrolyzable group and a molecular weight of 500 or more is dissolved in an organic solvent. To prepare an antioxidant solution.

-A hindered phenol type antioxidant having no hydrolyzable group and a molecular weight of 500 or more-
Here, the hydrolyzable group refers to an ester group, an amide group, an ether group or the like.
In this step, when a hindered phenol type antioxidant having a hydrolyzable group is used instead of the specific hindered phenol type antioxidant, the storage stability of the aqueous dispersion to be produced deteriorates, Heat resistance when used as a film deteriorates.

The specific hindered phenol type antioxidant has a high melting point and usually has poor dispersibility.
Therefore, a method for producing a polyolefin-based aqueous dispersion using a polyolefin resin previously kneaded with a specific hindered phenol-type antioxidant, or a powder of a specific hindered phenol-type antioxidant directly into a polyolefin-based aqueous dispersion. When blended and used in a method for producing a polyolefin-based aqueous dispersion, the dispersibility of the specific hindered phenol type antioxidant is deteriorated, and the heat resistance of the resulting coating film is also deteriorated.

The molecular weight of the specific hindered phenol type antioxidant is 500 or more.
If the molecular weight is 500 or more, even if the coating film is exposed to high temperature, the volatility of the antioxidant is low, so the heat resistance of the coating film is further improved.
The lower limit of the molecular weight is more preferably 600, and particularly preferably 700.
The upper limit of the molecular weight is not particularly limited, but the upper limit of the molecular weight is preferably 1000 from the viewpoint of further improving the compatibility and dispersibility, the viewpoint of easier availability, and the like. More preferably.

As the specific hindered phenol-type antioxidant, a known hindered phenol-type antioxidant having no hydrolyzable group and having a molecular weight of 500 or more can be selected and used.
In addition, as the specific hindered phenol type antioxidant, for example, a compound having a phenol skeleton having an alkyl group with high steric hindrance, having no hydrolyzable group, and having a molecular weight of 500 or more is used. it can.
Specifically as a specific hindered phenol type antioxidant, the compound represented by following General formula (1) is preferable.

In general formula (I), ^one of R ¹ and R ² represents a branched alkyl group having 3 to 10 carbon atoms, and the other of R ¹ and R ² is a hydrogen atom, a straight chain having 1 to 10 carbon atoms. A chain alkyl group or a branched alkyl group having 3 to 10 carbon atoms is represented.
In general formula (I), R ³ and R ⁴ each independently represent a hydrogen atom, a linear alkyl group having 1 to 10 carbon atoms, or a branched alkyl group having 3 to 10 carbon atoms.
L represents a single bond or a divalent linking group having no hydrolyzable group, A represents an n-valent linking group, and n represents 2 or 3.
A plurality of L, R ¹ , R ² , R ³ , and R ⁴ present in the general formula (I) may be the same or different from each other.

The linear alkyl group having 1 to 10 carbon atoms is preferably a linear alkyl group having 1 to 6 carbon atoms, more preferably a methyl group or an ethyl group, from the viewpoint of availability.
The branched alkyl group having 3 to 10 carbon atoms is preferably a branched alkyl group having 3 to 6 carbon atoms from the viewpoint of easy availability, i-propyl group, t-butyl group, i-butyl group. Or a s-butyl group is more preferred.

Further, the above formula (I), wherein ^{R 1} and said ^{R 2} are preferably both a branched alkyl group having 3 to 10 carbon atoms.
Moreover, in the said general formula (I), it is preferable that said R < ³ > and said R < ⁴ > are respectively independently a hydrogen atom or a C1-C10 linear alkyl group, a hydrogen atom or C1-C1 6 is more preferably a linear alkyl group, further preferably a hydrogen atom, a methyl group, or an ethyl group, and most preferably a hydrogen atom.

  The L is not particularly restricted unless it is a hydrolyzable functional group, but is preferably a methylene group or an ethylene group from the viewpoint of availability.

The n-valent linking group represented by A (n is 2 or 3) is an aromatic compound having no hydrolyzable group or a heterocyclic compound having no hydrolyzable group, and 2 hydrogen atoms. It is preferable that it is the residue except one piece or three pieces.
The group A is more preferably a group represented by the following formula (II-1) or the following formula (II-2).

In the formula (II-1) and the formula (II-2), “*” represents a bonding position with L in the general formula (I) (when L is a single bond, a carbon atom in the benzene ring) Represents the binding position).
In formula (II-1), R <^11> , R < ¹² > and R < ¹³ > represent a hydrogen atom or a C1-C10 alkyl group each independently.
The R ¹¹ , R ¹² and R ¹³ are preferably a hydrogen atom or a methyl group from the viewpoint of availability.

  Hereinafter, although the specific example (exemplary compound) of a specific hindered phenol type antioxidant is demonstrated, this invention is not limited by the following specific examples.

Exemplified compound (1) is 3,3 ′, 3 ″, 5,5 ′, 5 ″ -hexa-tert-butyl-a, a ′, a ″-(mesitylene-2,4,6-triyl) ) Tri-p-cresol (molecular weight 775), which is commercially available as “IRGANOX1330” manufactured by Ciba Japan.
Exemplified compound (2) is 1,3,5-tris (3,5-di-tert-butyl-4-hydroxybenzyl) -1,3,5-triazine-2,4,6 (1H, 3H, 5H). ) -Trione (molecular weight 784), which is commercially available as “IRGANOX 3114” manufactured by Ciba Japan.

A specific hindered phenol type antioxidant may be used individually by 1 type, and may use 2 or more types together.
The addition amount of the specific hindered phenol type antioxidant in the present invention is the entire resin (including polyolefin resin) contained in the aqueous dispersion of the present invention from the viewpoint of further improving the heat resistance when it is used as a coating film. It is preferable that it is 500 mass ppm or more and 3 mass% or less with respect to all the resin components), and it is more preferable that it is 1000 mass ppm or more and 2.0 mass% or less.

-Organic solvent-
The organic solvent in this step is not particularly limited as long as it is an organic solvent that dissolves the specific hindered phenol-type antioxidant. From the viewpoint of obtaining the effect of the present invention more effectively, the hindered at 25 ° C. An organic solvent that dissolves 0.1% by mass or more of the phenol-type antioxidant is preferable.
The organic solvent is preferably an organic solvent having a boiling point of 30 ° C. to 250 ° C. from the viewpoint of reducing the amount remaining in the coating film formed using the aqueous dispersion of the present invention. .

Moreover, as an organic solvent in this process, it is preferable that it is at least 1 sort (s) chosen, for example from the compound which has at least one of nitrogen and oxygen, and an aromatic compound.
Among the “compounds having at least one of nitrogen and oxygen”, examples of the nitrogen-containing organic solvent include acetonitrile, N-methylpyrrolidone, dimethylacetamide, and heterocyclic compounds.
Among the “compounds having at least one of nitrogen and oxygen”, examples of the oxygen-containing organic solvent include acetone, ethyl acetate, methyl acetate, ether, tetrahydrofuran, alcohol and the like.
Examples of the aromatic compound include benzene, toluene, xylene, phenol and the like.
Among the above, as the organic solvent in this step, N-methylpyrrolidone, acetone, dimethylacetamide, tetrahydrofuran, ethyl acetate, methyl acetate and toluene are more preferred, N-methylpyrrolidone and acetone are particularly preferred, and N-methylpyrrolidone is preferred. Most preferred.

The organic solvent in this process may be used individually by 1 type, and may use 2 or more types together.
Moreover, you may add a well-known additive (For example, the other additive mentioned later) to the antioxidant solution prepared at this process as needed.

(Mixing process)
In the mixing step in the present invention, the antioxidant solution and the polyolefin dispersion are mixed (with stirring as necessary).
There are no particular limitations on the mixing conditions. The mixing time varies depending on the temperature and other mixing conditions, but is usually about 10 minutes to 120 minutes.
Moreover, you may perform the dispersion | distribution process which is mentioned later as needed simultaneously with mixing or after mixing.

-Polyolefin dispersion-
The polyolefin dispersion is a dispersion in which a polyolefin resin is dispersed in an aqueous medium. Although this dispersion is substantially an aqueous dispersion, in order to distinguish it from the “aqueous dispersion” produced according to the present invention, it is referred to herein as “polyolefin dispersion”.
In the present invention, a polyolefin-based dispersion prepared in advance such as a commercial product may be used as the polyolefin-based dispersion, or a polyolefin-based dispersion prepared by preparing the polyolefin-based dispersion for each production of the aqueous dispersion of the present invention. You may use thing.

The method for preparing the polyolefin-based dispersion is not particularly limited. For example, a known dispersion treatment in which the polyolefin-based resin is dispersed in the aqueous medium by stirring in an aqueous medium while applying a shearing force can be used.
The dispersion treatment can be performed using a reaction apparatus capable of giving a decoction force such as an autoclave with a stirrer.
At this time, it is preferable to disperse by raising the temperature of the material to be dispersed to 90 ° C. or higher. Further, in order to improve the dispersion speed and increase the productivity, a dispersion process at a high temperature such as 130 ° C. to 160 ° C. or a dispersion process with a high shearing force such as a high stirring speed is possible.

-Polyolefin resin-
The polyolefin resin is not particularly limited as long as it is a resin obtained by polymerizing at least one olefin (monomer).
That is, the polyolefin-based resin is any one of a homopolymer of one olefin, a copolymer of two or more olefins, a copolymer of one or more olefins and one or more other monomers. There may be.
The polyolefin resin can be produced by a known method such as a method of polymerizing a monomer in the presence of a single site catalyst or a multisite catalyst.

Examples of the olefin (monomer) used in the production of the polyolefin resin include ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-decene, 1-dodecene, and 4-methyl-1- Examples include pentene.
Examples of the other monomer include acrylic acid esters such as acrylic acid, methacrylic acid, vinyl acetate, and methyl acrylate, and methacrylic acid esters such as methyl methacrylate.
In this specification, acrylic acid and methacrylic acid are collectively referred to as “(meth) acrylic acid”.

Specific examples of the polyolefin resin include polyethylene, polypropylene, an ethylene-α-olefin copolymer (for example, a copolymer of ethylene and an α-olefin having 3 to 20 carbon atoms), ethylene / (meth) acrylic acid. Examples thereof include ethylene-based copolymers, ethylene-vinyl acetate copolymers, and ethylene / (meth) acrylic acid ester copolymers.
Among these, from the viewpoint of dispersibility in an aqueous medium, an ethylene / (meth) acrylic acid copolymer is preferable. The ethylene / (meth) acrylic acid copolymer can be dispersed in an aqueous medium only by using a neutralizing agent and without using a dispersing aid such as a surfactant.

--E (M) AA copolymer--
The ethylene / (meth) acrylic acid copolymer is an ethylene / (meth) acrylic acid copolymer (hereinafter referred to as “a”) containing at least a structural unit derived from ethylene and a structural unit derived from (meth) acrylic acid. E (M) AA copolymer ”. The E (M) AA copolymer is preferably a random copolymer.

In the E (M) AA copolymer, the presence of a structural unit derived from (meth) acrylic acid is essential. The presence of the structural unit is essential to indicate that (meth) acrylic acid is positively contained.
The E (M) AA copolymer preferably contains 8% by mass or more of a (meth) acrylic acid-derived structural unit based on the total mass of the E (M) AA copolymer. Hereinafter, the E (M) AA copolymer in the present invention containing 8% by mass or more of a structural unit derived from (meth) acrylic acid is also referred to as “specific E (M) AA copolymer”.

  Moreover, content of the structural unit derived from (meth) acrylic acid is 30 mass% or less with respect to the total mass of specific E (M) AA copolymer from industrial availability. Preferably, it is 25 mass% or less.

  The specific E (M) AA copolymer is not only a binary copolymer composed of a structural unit derived from ethylene and a structural unit derived from (meth) acrylic acid, but also other structural units. You may comprise the ternary or more copolymer which has further the structural unit derived from a monomer.

  Examples of the other monomers include vinyl esters such as vinyl acetate and vinyl propionate, methyl acrylate, ethyl acrylate, isobutyl acrylate, n-butyl acrylate, methyl methacrylate, isobutyl methacrylate, and maleic acid. Examples thereof include unsaturated carboxylic acid esters such as dimethyl and diethyl maleate, and carbon monoxide.

  The other monomer can be contained, for example, in a proportion of 20% by mass or less with respect to the total mass of the specific E (M) AA copolymer.

  The melt flow rate of the specific E (M) AA copolymer (hereinafter sometimes abbreviated as MFR) is preferably in the range of 10 to 1000 g / 10 minutes. Furthermore, the MFR is more preferably in the range of 20 to 600 g / 10 minutes. In addition, MFR is a value measured by 190 degreeC and load 2160g based on JISK7210-1999. The same applies hereinafter.

  The specific E (M) AA copolymer can be obtained by radical copolymerization under high temperature and high pressure. In the market, it is available under the trade name Nukurel (Mitsui / DuPont Polychemical Co., Ltd.) and under the trade name Primacor (Dow Chemical Japan Co., Ltd.).

  As a method for producing a dispersion of the specific E (M) AA copolymer, some or all of the carboxyl groups of the specific E (M) AA copolymer may be converted to amine compounds (ammonia, alkylamines, alkanolamines). Etc.) and at least one selected from alkali metal hydroxides (potassium hydroxide, sodium hydroxide, etc.), and a method of forming a dispersion by dispersing the copolymer in water. Are known.

Part or all of the carboxyl group of the specific E (M) AA copolymer is converted into an amine compound (ammonia, alkylamines, alkanolamines, etc.), and an alkali metal hydroxide (potassium hydroxide, sodium hydroxide, etc.) In the case of neutralizing with at least one selected from (A), it is selected from amine compounds (ammonia, alkylamines, alkanolamines, etc.) and alkali metal hydroxides (potassium hydroxide, sodium hydroxide, etc.). The degree of neutralization by the total of at least one kind is preferably 40 mol% or more with respect to the number of moles of acid groups, particularly carboxyl groups of the specific E (M) AA copolymer, in terms of suppressing increase in viscosity. More preferably, it is in the range of mol% to 300 mol%.
The degree of neutralization refers to base compounds (amine compounds (ammonia, alkylamines, alkanolamines, etc.)) and alkali metal hydroxides (water) relative to the number of moles of acid groups in the E (M) AA copolymer. The blending ratio (mol%) of at least one selected from potassium oxide, sodium hydroxide and the like).

-Other ingredients-
The polyolefin dispersion is not particularly limited as long as the polyolefin resin is dispersed in an aqueous medium such as water, but may contain other components as necessary.
Examples of other components include a dispersant for dispersing the polyolefin-based resin and monohydric alcohols.

The polyolefin dispersion may contain other known additives.
Other additives include polyhydric alcohols such as glycerin, ethylene glycol, polyethylene glycol, and polypropylene glycol; water-soluble epoxy compounds; methanol, ethanol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol monomethyl ether, propylene glycol Ethers such as diethyl ether, diethylene glycol monoethyl ether and dipropylene glycol monomethyl ether; esters such as ethylene glycol monoacetate and propylene glycol monoacetate; and antioxidants, weathering stabilizers, ultraviolet absorbers, light stabilizers, Antistatic agent, plasticizer, pigment, dye, antibacterial agent, lubricant, anti-blocking agent, rust preventive agent, adhesive, cross-linking agent, writability improver, none Fillers, and the like can be exemplified foaming agent.

(Other processes)
The method for producing an aqueous dispersion of the present invention may have other steps other than the above-described antioxidant solution preparation step and mixing step, if necessary.
As other steps, a step of further dispersing treatment after the mixing step, a step of adding known additives (for example, the above-mentioned other additives), other dispersions other than the aqueous dispersion of the present invention, and other steps The process etc. which mix with a solution are mentioned.

As said other dispersion, the resin dispersion which does not contain a specific hindered phenol type antioxidant can be used.
As the other dispersion, for example, a dispersion having a pH of 7 or more, or a dispersion having a pH of 7 or more with aqueous ammonia and the like, which does not gel when mixed with the aqueous dispersion of the present invention is selected. It is desirable to do. The other dispersions have an average dispersed particle diameter of 1 nm to 10,000 nm, preferably 5 nm to 5,000 nm, and a solid content concentration of 2% by mass to 60% by mass, particularly 5% by mass to 50% by mass. It is desirable to select one.

Examples of other dispersions include polyvinyl acetate, ethylene / vinyl acetate copolymer, polyvinyl chloride, polyvinylidene chloride, water-soluble acrylic resin, acrylamide resin, methacrylamide resin, acrylonitrile resin, methacrylonitrile resin, Styrene / acrylic acid copolymer, water-soluble polyurethane resin, water-soluble styrene / maleic acid copolymer, styrene / butadiene copolymer, high impact polystyrene resin, butadiene resin, polyester resin, acrylonitrile / butadiene copolymer, polyethylene resin , Polyethylene oxide resin, propylene / ethylene copolymer, maleic anhydride grafted polypropylene, maleic anhydride grafted polyolefin such as maleic anhydride grafted polyethylene, chlorinated polyethylene, chlorinated polypropylene, E DM (ethylene - propylene - diene copolymer), phenolic resin, silicone resin, an aqueous dispersion such as an epoxy resin.
These may be used alone or in combination of two or more.

  Furthermore, you may use 2 or more types of other dispersions for a mixing | blending. Preparation of the mixed dispersion which mix | blended the aqueous dispersion liquid of this invention and another dispersion can be obtained by mixing several types to mix | blend at room temperature, stirring. This mixed dispersion can also be used in the same manner as the aqueous dispersion of the present invention. In preparing the mixed dispersion, the base resin (E (M) AA copolymer) of the aqueous dispersion of the present invention and the base resin contained in the other dispersion to be blended are melt blended in advance. Alternatively, it may be dry blended and then dispersed in water. The present invention is not limited by such a manufacturing method.

The aqueous dispersion of the present invention and the production method thereof have been described above.
The concentration of the polyolefin-based resin (solid content concentration [mass standard]) in the aqueous dispersion of the present invention is preferably 30% by mass or less based on the total mass of the aqueous dispersion. When the solid content concentration is 30% by mass or less, it is possible to obtain a good aqueous dispersion. For example, when used as a rust preventive paint for steel, a rust preventive paint having excellent uniformity in coating film It is easy to make. Especially, preferable solid content concentration is 5 mass%-30 mass%, More preferably, it is 15 mass%-25 mass%.

Further, the viscosity (25 ° C.) of the aqueous dispersion of the present invention is appropriately adjusted depending on the target range such as applicability and handleability, but is preferably in the range of 100 mPa · s to 20,000 mPa · s, more preferably. The range is from 100 mPa · s to 2,000 mPa · s.
The viscosity of the aqueous dispersion is measured by adjusting the aqueous dispersion to 25 ° C. using a Brookfield viscometer (manufactured by Brookfield).

  Since the aqueous dispersion of the present invention can form a coating film having excellent heat resistance, it can be used in various applications such as anti-rust paints (or raw materials for anti-rust paints) and heat seal laminates. Can be used widely.

<Laminated body>
The laminate of the present invention is a laminate having a substrate and a film formed using the above-described aqueous dispersion of the present invention.
The aqueous dispersion of the present invention (or a mixed dispersion of this and other aqueous dispersions) can be formed by coating on an arbitrary substrate to form a film. A laminate having a film formed using a dispersion liquid can be formed.
The laminate of the present invention can be produced, for example, by applying the aqueous dispersion of the present invention or a mixed dispersion of this and another aqueous dispersion on a substrate and drying it.

  As a method for forming a coating film comprising the aqueous dispersion of the present invention on a substrate, known methods such as roll coating, bar coating, air knife coating, reverse roll coating, doctor coating, brush coating, spray coating, etc. A coating method, a printing method such as screen printing, gravure printing, engraving roll printing, flexographic printing, or a method of immersing a substrate in the aqueous dispersion of the present invention can be applied.

  In addition, after forming a coating film made of an aqueous dispersion on the substrate by coating or the like, the moisture may be evaporated by forcibly heating and drying in addition to natural drying in the atmosphere. A uniform film is obtained. Heat drying can heat and dry at a temperature of about 80 ° C. to 200 ° C. to evaporate volatile components such as water and alkanolamine, thereby obtaining a laminate having a coating film having a desired thickness.

Although the thickness of the film obtained by drying after being formed by coating or the like is arbitrary, it is usually 1 μm to 20 μm, preferably 1 μm to 10 μm. When the thickness is within the above range, for example, the volume of the packaging material can be reduced, and low temperature heat sealability can be obtained. Furthermore, a rust preventive film can be formed.
The formed film may be subjected to a crosslinking treatment by electron beam irradiation for the purpose of improving water resistance, durability and the like.

  The aqueous dispersion of the present invention can be used as a rust preventive paint or a raw material for a rust preventive paint. In addition, the aqueous dispersion of the present invention can be used for the production of a heat-sealable laminate obtained by applying it to a substrate and drying it.

As a form of a base material, any of molded objects, such as a film, a sheet | seat, and a container, may be sufficient.
The base material is polyolefin, ethylene / vinyl acetate copolymer, ethylene / (meth) acrylic acid ester copolymer, ethylene / (meth) acrylic acid copolymer or its ionomer, ethylene / (meth). Olefin polymer such as acrylic acid / (meth) acrylic acid ester copolymer or ethylene / polar monomer copolymer such as its ionomer, polyester, polyamide, polycarbonate, polyvinyl chloride, polystyrene, ABS resin, styrene / butadiene Styrenic polymers such as block copolymers, vinyl alcohol polymers such as polyvinyl alcohol and ethylene / vinyl alcohol copolymers, polyamides such as nylon 6 and nylon 66, arbitrary blend materials thereof, metals (iron, copper, Aluminum, stainless steel, etc.), wood, , Textile (nylon, polyester, acrylic, urethane, rayon, etc.), and the like can be exemplified leather (natural or synthetic leather).

  Examples of the polyolefin that can be used as a substrate include homopolymers such as ethylene, propylene, 1-butene, 1-hexene, 1-octene, 1-decene, 1-dodecene, 4-methyl-1-pentene, and olefins thereof. And a copolymer of each other. Specifically, various polyethylene, polypropylene, poly-4-methyl-1-pentene, and the like. Examples of polyethylene include high-density polyethylene, medium-density polyethylene, high-pressure low-density polyethylene, and linear low-density polyethylene (ethylene / α-olefin copolymer). Examples of the α-olefin in the linear low density polyethylene include propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-decene, 1-dodecene, 4-methyl-1-pentene and the like. it can. The linear low density polyethylene may be produced by any catalyst system, and for example, a copolymer obtained in the presence of a single site catalyst or a multisite catalyst can be used.

Examples of the polyester that can be used as the substrate include polyethylene terephthalate, polytrimethylene terephthalate, polytetramethylene terephthalate, and polyethylene-2,6-naphthalenedicarboxylate.
Examples of the polyamide usable as a substrate include polycondensation of dicarboxylic acid and diamine, ring-opening polymerization of lactam, polycondensation of aminocarboxylic acid, or copolymerization of lactam, dicarboxylic acid and diamine. For example, generally nylon 4, nylon 6, nylon 46, nylon 66, nylon 612, nylon 6T, nylon 11, nylon 12, nylon 6/66, nylon 6/12, nylon 6/610, nylon Commercially available products such as 66/12, nylon 6/66/610, MX nylon and the like can be used. As the polyamide, nylon 6 and nylon 66 are particularly suitable.

  In the heat-sealable laminate, a film substrate or a metal substrate is preferable as the substrate from the viewpoint of utilization as a packaging material or a metal rust prevention material such as a rust preventive paint. As the film substrate, for example, a film having a thickness of about 10 to 300 μm is preferable, and a film having a thickness of about 10 to 100 μm is preferable particularly for volume reduction purposes. Specifically, those excellent in functionality such as gas barrier properties, moisture resistance, heat resistance, transparency, toughness, wear resistance and the like are preferable. For example, a stretched or non-stretched film of a polar material or a nonpolar material can be mentioned. The film substrate may be a laminated film having a two-layer structure or more in addition to a single-layer structure. This laminated film may have an adhesive layer as an intermediate layer. Specific examples include unstretched films such as polyester, polyamide, and ethylene / vinyl alcohol copolymer, uniaxially stretched film or biaxially stretched film, polypropylene biaxially stretched film, and high-density polyethylene uniaxially stretched film. Polyolefin stretched film, polyolefin non-stretched film such as poly-4-methylpentene, polypropylene, polyethylene Mention may be made of woven or non-woven fabrics composed of fibers, semi-synthetic fibers or natural fibers, natural leather or synthetic leather.

  Moreover, when it uses as a rust preventive coating material or a raw material of a rust preventive coating material, a rust preventive metal base material is obtained. In this case, the metal material constituting the metal substrate is preferably a plate-like material having a thickness of, for example, 500 μm to 5,000 μm, particularly 1,000 μm to 2,000 μm. In addition, the thing of the thickness remove | deviating from this range can also be used.

  As the metal or inorganic oxide vapor deposition film, stretched or unstretched films such as polyester, polyamide, polyvinyl alcohol, ethylene / vinyl alcohol copolymer, polycarbonate, polyolefin, etc., metals such as aluminum, silica, alumina, magnesia, An inorganic oxide such as titanium oxide is deposited by vacuum deposition, chemical plating, sputtering, or the like. The vapor deposition thickness is preferably about 50 Å to 2,000 Å, for example.

  When the film substrate is a laminated film, a laminated film including at least one layer of the exemplified film is preferable. When the laminated film includes an adhesive layer, an ethylene / unsaturated carboxylic acid copolymer, an ethylene / vinyl acetate copolymer, an ethylene / unsaturated carboxylic acid ester copolymer, an unsaturated carboxylic acid-modified polyolefin, etc. It can be used as an adhesive layer.

  The base material may be subjected to corona treatment for the purpose of improving adhesiveness or the like, or may be subjected to primer treatment in advance. In particular, when a resin film is used as a base material, it is preferable to perform a primer treatment.

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples unless it exceeds the gist thereof. “Ethylene content” indicates a copolymerization ratio of repeating structural units derived from ethylene, and “(meth) acrylic acid content” indicates a copolymerization ratio of repeating structural units derived from (meth) acrylic acid. MFR is a mel flow rate value measured at 190 ° C. under a load of 2160 g in accordance with JIS K7210-1999.
In the following examples, “room temperature” refers to 25 ° C.

[Example 1]
<Preparation of polyolefin dispersion>
In a 300 ml autoclave, ethylene / acrylic acid copolymer (ethylene content: 80% by mass, acrylic acid content: 20% by mass, MFR = 300 g / 10 min) (hereinafter also referred to as “EAA”) and ion-exchanged water 214 g And 29 g of an aqueous ammonia solution having an ammonia concentration of 10% by mass were stirred at a temperature of 150 ° C. and a stirring speed of 800 rpm for 1 hour. At this time, the degree of neutralization of ammonia (ratio of ammonia to the number of moles of carboxyl groups of the ethylene / acrylic acid copolymer) was 75 mol%. Thereafter, it was gradually cooled with tap water at a temperature decreasing rate of 1 to 3 ° C./min to obtain a polyolefin-based dispersion. The resulting polyolefin dispersion had a solid content concentration (EAA copolymer; the same applies hereinafter) of 25% by mass.

<Preparation of antioxidant solution>
Add 0.1 g of the exemplified compound (1) as a specific hindered phenolic antioxidant to 5 mL of N-methylpyrrolidone (hereinafter also referred to as “NMP”) as an organic solvent, and dissolve it at room temperature for 10 minutes to prevent oxidation. An agent solution was prepared.
NMP dissolved 5% by mass or more of the exemplified compound (1) at 25 ° C.

<Mixing process>
200 mL of the polyolefin dispersion and 5 mL of the antioxidant solution were mixed with stirring at room temperature for 10 minutes.
Thus, an aqueous dispersion was obtained.
In the obtained aqueous dispersion, the amount of the specific hindered phenol-based antioxidant (Exemplary Compound (1)) added to the resin (EAA) was 0.2% by mass as shown in Table 1.

<Production of laminate>
Using the aqueous dispersion obtained above, this was coated on a 100 μm thick polyethylene terephthalate (PET) film (base material) and dried to form a coating film having a dry film thickness of 10 μm. Obtained.
Moreover, using the aqueous dispersion obtained above, it was applied on a 0.5 mm steel plate (base material) defined by JIS G3141, dried, and a coating film having a dry film thickness of 10 μm was formed. Obtained.

<Evaluation>
Subsequently, the following evaluation was performed on the obtained aqueous dispersion and laminated film (or coated steel sheet). The evaluation results are shown in Table 1 below.

[1] Dispersibility The obtained aqueous dispersion was visually observed, and the dispersibility was evaluated according to the following evaluation criteria.
-Evaluation criteria-
○: Uniformly dispersed.
X: Separated.

[2] Storage stability The obtained aqueous dispersion was left in the atmosphere at 23 ° C. for 1 week and evaluated according to the following evaluation criteria.
-Evaluation criteria-
A: Precipitation and decomposition of the antioxidant and discoloration of the aqueous dispersion were not observed, and the storage stability was good.
B: Sedimentation of a small amount of the antioxidant was observed, but it was possible to disperse by re-stirring, and no decomposition of the antioxidant and discoloration of the aqueous dispersion were observed, and the storage stability was within a practically acceptable range Met.
C: Precipitation and decomposition of the antioxidant and discoloration of the aqueous dispersion were observed, storage stability was poor, and the practically acceptable range was exceeded.

[3] Heat resistance of coating film The obtained laminated film (or coated steel sheet) was subjected to an aging test in an oven at 220 ° C for 20 minutes, and the heat resistance of the coating film was evaluated according to the following evaluation criteria.
-Evaluation criteria-
A: There was almost no crack and coloring of the coating film, and the heat resistance of the coating film was favorable.
B: The coating film was slightly colored but not cracked, and the heat resistance of the coating film was within a practically acceptable range.
C: The crack and coloring of the coating film were severe, the heat resistance of the coating film was poor, and the practically acceptable range was exceeded.

[Examples 2 to 10]
In Example 1, except that the type of polyolefin resin, the type and amount of antioxidant, and the type of organic solvent were changed as shown in Table 1 below, an aqueous dispersion and laminate were obtained in the same manner as in Example 1. The same evaluation as in Example 1 was performed.
The evaluation results are shown in Table 1 below.

NMP dissolved 5% by mass or more of the exemplified compound (2) at 25 ° C.
Acetone dissolved 5% by mass or more of Exemplified Compound (1) at 25 ° C.
Acetone dissolved 5% by mass or more of Exemplified Compound (2) at 25 ° C.

In Examples 9 and 10, the following polyethylene (PE) and polypropylene (PP) resin dispersions were used as the polyolefin-based dispersion.
-Polyethylene (PE) and polypropylene (PP) resin dispersion-
-Polyethylene (PE) resin dispersion: Chemipearl W400 manufactured by Mitsui Chemicals, Inc.
Polypropylene (PP) resin dispersion: Chemipearl WP100 manufactured by Mitsui Chemicals, Inc.

[Comparative Example 1]
In Example 1, an antioxidant solution was not prepared, and a polyolefin dispersion was used as an aqueous dispersion to produce a laminate in the same manner as in Example 1. The aqueous dispersion and the laminate were obtained in Example 1. The same evaluation was performed.
The evaluation results are shown in Table 1 below.

[Comparative Example 2]
An aqueous dispersion was prepared in the same manner as in Example 1 except that an antioxidant solution was prepared using BHT (dibutylhydroxytoluene) having a molecular weight of 220 instead of the exemplified compound (1) in Example 1. . A laminate was prepared using the obtained aqueous dispersion in the same manner as in Example 1, and the same evaluation as in Example 1 was performed on the aqueous dispersion and the laminate.
The evaluation results are shown in Table 1 below.

[Comparative Example 3]
In Example 1, an antioxidant solution was not prepared, and Exemplified Compound (1) was added directly to the polyolefin dispersion to obtain an aqueous dispersion. A laminate was prepared using the obtained aqueous dispersion in the same manner as in Example 1, and the same evaluation as in Example 1 was performed on the aqueous dispersion and the laminate.
The evaluation results are shown in Table 1 below.

As shown in Table 1, in the examples, the storage stability and the heat resistance of the formed coating film were excellent.
In contrast, in the comparative example, at least one of storage stability and heat resistance of the formed coating film deteriorated.

Claims (9)

A step of preparing an antioxidant solution by dissolving a hindered phenol-type antioxidant having no hydrolyzable group and a molecular weight of 500 or more in an organic solvent;
Mixing the antioxidant solution with a polyolefin dispersion in which a polyolefin resin is dispersed in an aqueous medium;
A method for producing an aqueous dispersion having   The method for producing an aqueous dispersion according to claim 1, wherein the organic solvent dissolves the hindered phenol-type antioxidant at 0.1% by mass or more at 25 ° C and has a boiling point of 30 ° C to 250 ° C.   The method for producing an aqueous dispersion according to claim 1, wherein the organic solvent is at least one selected from a compound having at least one of nitrogen and oxygen in the structure and an aromatic compound.   The method for producing an aqueous dispersion according to any one of claims 1 to 3, wherein the organic solvent is at least one of N-methylpyrrolidone and acetone. The method for producing an aqueous dispersion according to any one of claims 1 to 4, wherein the hindered phenol-type antioxidant is a compound represented by the following general formula (I).

[In General Formula (I), ^one of R ¹ and R ² represents a branched alkyl group having 3 to 10 carbon atoms, and the other of R ¹ and R ² is a hydrogen atom, having 1 to 10 carbon atoms. A linear alkyl group or a branched alkyl group having 3 to 10 carbon atoms is represented.
In general formula (I), R ³ and R ⁴ each independently represent a hydrogen atom, a linear alkyl group having 1 to 10 carbon atoms, or a branched alkyl group having 3 to 10 carbon atoms.
In general formula (I), L represents a single bond or a divalent linking group having no hydrolyzable group, A represents an n-valent linking group, and n represents 2 or 3.
A plurality of L, R ¹ , R ² , R ³ , and R ⁴ present in the general formula (I) may be the same or different from each other. ]   The hindered phenol type antioxidant is 3,3 ′, 3 ″, 5,5 ′, 5 ″ -hexa-tert-butyl-a, a ′, a ″-(mesitylene-2,4, 6-triyl) tri-p-cresol and 1,3,5-tris (3,5-di-tert-butyl-4-hydroxybenzyl) -1,3,5-triazine-2,4,6 (1H, The method for producing an aqueous dispersion according to any one of claims 1 to 5, which is at least one of 3H, 5H) -trione.   The aqueous amount according to any one of claims 1 to 6, wherein an addition amount of the hindered phenol type antioxidant is 500 mass ppm or more and 3 mass% or less with respect to the entire resin in the aqueous dispersion. A method for producing a dispersion.   The aqueous dispersion manufactured using the manufacturing method of the aqueous dispersion of any one of Claims 1-7.   The laminated body which has a base material and the film | membrane formed using the aqueous dispersion liquid of Claim 8.