CN112888749A

CN112888749A - Aqueous resin composition, method for producing same, and use thereof

Info

Publication number: CN112888749A
Application number: CN201980069300.6A
Authority: CN
Inventors: 伊藤匠; 白石谕勲; 坂元芳峰; 下道谦太
Original assignee: Nippon Shokubai Co Ltd
Current assignee: Nippon Shokubai Co Ltd
Priority date: 2018-10-22
Filing date: 2019-10-18
Publication date: 2021-06-01
Also published as: JPWO2020085260A1; JP7237086B2; WO2020085260A1

Abstract

Provided are an aqueous resin composition having excellent adhesion to a polyolefin substrate and a method for producing the same. The problem is solved by an aqueous resin composition comprising: a non-chlorinated polyolefin having a carboxyl group; an acrylic resin containing a structural unit derived from a surfactant having a polymerizable group; and an aqueous medium.

Description

Aqueous resin composition, method for producing same, and use thereof

Technical Field

The present invention relates to an aqueous resin composition, a method for producing the same, and use thereof.

Background

Polyolefin molded articles such as polyethylene and polypropylene are used for parts such as vehicle bumpers and vehicle moldings and parts of home electric appliances, and exterior coatings are applied to the surfaces of the molded articles. In order to improve the adhesion between the exterior coating film and the molded article, a primer is applied in advance at the time of coating. As such a primer, a solvent-based primer containing chlorinated polyolefin has been conventionally used, but in recent years, in consideration of the influence on the environment, a water-based paint not using an organic solvent and halogen has been developed (for example, patent documents 1 to 3).

(Prior art document)

(patent document)

Patent document 1: japanese laid-open patent publication No. 2011- "

Patent document 2: japanese laid-open patent publication No. 2015-214600 "

Patent document 3: international publication No. 2007/094510

Disclosure of Invention

(problems to be solved by the invention)

However, the conventional water-based paint which does not use an organic solvent or halogen as described above is still insufficient in adhesion to polyolefin substrates.

An object of one aspect of the present invention is to provide an aqueous resin composition having excellent adhesion to a polyolefin substrate, and a method for producing the same.

(means for solving the problems)

The present inventors have intensively studied to solve the above problems and as a result, have found that an aqueous resin composition comprising a non-chlorinated polyolefin having a carboxyl group and an acrylic resin having a specific structural unit can achieve excellent adhesion to a polyolefin substrate, and have completed the present invention.

That is, the aqueous resin composition according to an embodiment of the present invention includes: a non-chlorinated polyolefin having a carboxyl group; an acrylic resin containing a structural unit derived from a surfactant having a polymerizable group; and an aqueous medium.

The method for producing an aqueous resin composition according to one embodiment of the present invention includes a mixing step of mixing a polyolefin aqueous dispersion (a) containing a non-chlorinated polyolefin having a carboxyl group and an aqueous medium and an acrylic resin aqueous dispersion (B) obtained by emulsion polymerization of a monomer in the presence of a surfactant having a polymerizable group.

(Effect of the invention)

According to one aspect of the present invention, an aqueous resin composition having superior adhesion to polyolefin substrates can be realized.

Detailed Description

An embodiment of the present invention will be described below, but the present invention is not limited to this. The present invention is not limited to the embodiments described below, and various modifications can be made within the scope shown in the specification, and embodiments and examples obtained by appropriately combining technical means disclosed in different embodiments and examples are also included in the technical scope of the present invention. In the present specification, "adhesion" refers to adhesion to a polyolefin substrate, and is a physical property that can be evaluated by an initial adhesion evaluation method (cross-cut test) described in examples below. The term "peel strength" refers to the peel strength between the polyolefin substrate and the coating film after the coating film to be evaluated to which the tape is attached is left to stand at 23 ℃ and 65% RH for 1 day, and the peel strength can be measured by the peel strength evaluation method (peel strength test) described in the following examples, and is a physical property different from "adhesiveness". In the present specification, "a to B" each indicating a numerical range means "a to B inclusive" unless otherwise specified.

[ 1. Water-based resin composition ]

An aqueous resin composition according to an embodiment of the present invention includes: a non-chlorinated polyolefin having a carboxyl group; an acrylic resin containing a structural unit derived from a surfactant having a polymerizable group; and an aqueous medium.

In other words, the aqueous resin composition according to an embodiment of the present invention includes: the acrylic resin contains a structural unit derived from a surfactant having a polymerizable group.

[ 1.1 non-chlorinated polyolefin having carboxyl group ]

The aqueous resin composition according to an embodiment of the present invention contains a non-chlorinated polyolefin having a carboxyl group. Here, the non-chlorinated polyolefin having a carboxyl group may be a polyolefin which is not chlorinated and to which a carboxyl group is bonded. Examples of the non-chlorinated polyolefin having a carboxyl group include acid-modified non-chlorinated polyolefins. Examples of the acid-modified non-chlorinated polyolefin include acid-modified non-chlorinated polyolefins which are subjected to at least one selected from unsaturated carboxylic acids, anhydrides of unsaturated carboxylic acids, and derivatives of unsaturated carboxylic acids (hereinafter, also referred to as "unsaturated carboxylic acids and the like" in the present specification), and for example, copolymers obtained by graft copolymerization of unsaturated carboxylic acids and the like with non-chlorinated polyolefins can be used.

The polyolefin may be a polymer of an olefin compound, and is not particularly limited. Examples of the olefin compound include ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, and 4-methyl-1-pentene. The polyolefin may be a homopolymer obtained by polymerizing 1 of these olefin compounds or a copolymer obtained by copolymerizing 2 or more of these olefin compounds, and among these, a copolymer is preferable. Further, the polyolefin, if a copolymer, may be a random copolymer, a block copolymer, or a graft copolymer. Among the above olefin compounds, ethylene and propylene are more preferable.

Examples of the polyolefin include homopolymers such as polyethylene and polypropylene, and poly α -olefin copolymers obtained by copolymerizing α -olefin-containing monomers. As the polyalphaolefin, for example, a propylene- α -olefin copolymer is preferable. Here, the propylene- α -olefin copolymer has propylene as a main component and is obtained by copolymerizing propylene with an α -olefin. As the α -olefin, for example, 1 or 2 or more species of ethylene, 1-butene, 1-heptene, 1-octene, 4-methyl-1-pentene and the like can be used. Among these, 1-butene is more preferable. In addition, the polyolefin is preferably a polyolefin having propylene as a constituent unit from the viewpoint of adhesion of a formed coating film or the like, and in this case, the content of the propylene unit in the polyolefin is preferably 50 to 100% by mass, more preferably 70 to 99% by mass from the viewpoint of adhesion of a formed coating film or the like.

More specific examples of the polyolefin include Hardlen (registered trademark) NZ-1004, NZ-1015, etc. (manufactured by Toyobo Co., Ltd.); arrow Base (registered trademark) DA, TD, SB, TC, SE, YA, DB, etc., or Arrow Base (registered trademark) SB-1200, SE-1200, SD-1200, DA-1010, DB-4010, etc. (Unitika corporation).

The method for producing the polyolefin is not particularly limited, and for example, a polyolefin polymerized using a metallocene catalyst is preferable because it has uniform crystallinity and is excellent in solubility in a solvent. The polyolefin has a melting point Tm of 60 to 125 ℃, preferably 60 to 100 ℃, and more preferably 60 to 90 ℃ from the viewpoint of improving the adhesion of the formed coating film.

Examples of the unsaturated carboxylic acid include acrylic acid, methacrylic acid, maleic acid, fumaric acid, citraconic acid, mesaconic acid, itaconic acid, aconitic acid, and crotonic acid. Examples of the acid anhydride of the unsaturated carboxylic acid include maleic anhydride and itaconic anhydride. Further, as the derivative of the acid anhydride of the unsaturated carboxylic acid, a half ester, a half amide, and the like of the unsaturated carboxylic acid can be mentioned. Among the above unsaturated carboxylic acids, acrylic acid, methacrylic acid, maleic anhydride and the like are more preferably used.

The graft polymerization amount by the unsaturated carboxylic acid or the like may be appropriately changed depending on the desired physical properties of the formed coating film, and is preferably 0.1 to 10% by mass, more preferably 1 to 5% by mass, based on the mass of the solid content of the polyolefin having a carboxyl group. In order to stably disperse the polyolefin in water, the graft polymerization amount by the unsaturated carboxylic acid or the like, in other words, the content of the unsaturated carboxylic acid or the like is preferably 0.1 mass% or more and 10 mass% or less.

Examples of the method for graft-copolymerizing the unsaturated carboxylic acid or the like with the polyolefin include known methods such as a solution method and a melt method.

The solution method is performed, for example, as follows. That is, at least 1 kind of the polyolefin is dissolved in an aromatic organic solvent such as toluene at 100 to 180 ℃, and then at least 1 kind selected from the unsaturated carboxylic acids and the like is added, and a radical initiator is added at once or in portions to react.

The melting method is performed, for example, as follows. That is, at least 1 kind of the polyolefin is heated to a temperature of the melting point or more to melt it, and then at least 1 kind selected from the unsaturated carboxylic acids and the like and a radical initiator are added and reacted.

Examples of the radical initiator include benzoyl peroxide, dicumyl peroxide, di-t-butyl peroxide, and the like, and can be selected according to the reaction temperature and the decomposition temperature.

The non-chlorinated polyolefin having a carboxyl group preferably has a weight average molecular weight of 5000 to 200000, more preferably 30000 to 120000. The weight average molecular weight is preferably 5000 or more, and thus the final aqueous resin composition is excellent in adhesion and peel strength. The weight average molecular weight is preferably 200000 or less, whereby the dispersion in water can be made good. Here, in the present specification, the weight average molecular weight is a polystyrene-equivalent molecular weight measured by Gel Permeation Chromatography (GPC).

The non-chlorinated polyolefin having a carboxyl group may be used in 1 kind or in combination of 2 or more kinds.

In one embodiment of the present invention, the non-chlorinated polyolefin having a carboxyl group may be mixed with the acrylic resin aqueous dispersion (B) described later in the form of a polyolefin aqueous dispersion (a) dispersed in an aqueous medium. The polyolefin aqueous dispersion (A) comprises a non-chlorinated polyolefin having a carboxyl group and an aqueous medium. The polyolefin aqueous dispersion (a) may contain a polyolefin other than the non-chlorinated polyolefin having a carboxyl group. In the present specification, water is generally used as the aqueous medium, and if necessary, a hydrophilic organic solvent such as a lower alcohol such as methanol or ethanol may be used in combination.

The content of the non-chlorinated polyolefin having a carboxyl group in the polyolefin aqueous dispersion (a) may be appropriately adjusted depending on the aqueous dispersion and primer composition to be finally obtained, and the content of the non-chlorinated polyolefin having a carboxyl group in the polyolefin aqueous dispersion (a) is 5 to 60% by mass, preferably 10 to 50% by mass, more preferably 15 to 45% by mass, and still more preferably 20 to 40% by mass.

Further, as the polyolefin aqueous dispersion (a), a reaction solution obtained in the step of graft-copolymerizing the unsaturated carboxylic acid or the like with the polyolefin may be used as it is.

[ 1.2 acrylic resin ]

An aqueous resin composition according to an embodiment of the present invention includes an acrylic resin containing a structural unit derived from a surfactant having a polymerizable group.

As the acrylic resin, for example, an acrylic resin containing a structural unit derived from a (meth) acrylate and a structural unit derived from a surfactant having a polymerizable group can be preferably used. In the present specification, "(meth) acrylic acid" means "methacrylic acid" and "acrylic acid".

Preferred examples of the (meth) acrylic acid ester usable as the monomer include, for example, alkyl (meth) acrylates such as methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, n-pentyl (meth) acrylate, n-hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, tridecyl (meth) acrylate, cyclohexyl (meth) acrylate, n-octyl (meth) acrylate, and n-lauryl (meth) acrylate; benzyl (meth) acrylate; 2- (acetoacetoxy) ethyl (meth) acrylate; hydroxyalkyl (meth) acrylates such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, and 4-hydroxybutyl (meth) acrylate; (meth) acrylates having an oxo group such as ethylene glycol (meth) acrylate, ethylene glycol methoxy (meth) acrylate, diethylene glycol methoxy (meth) acrylate and the like; (meth) acrylates having polyoxyalkylene groups, and the like. These may be used alone or in combination of 2 or more. Among them, the (meth) acrylate is preferably an alkyl (meth) acrylate having 1 to 12 carbon atoms in the alkyl group, from the viewpoint of adhesion of the aqueous resin composition to a polyolefin substrate. From the same viewpoint, among the alkyl (meth) acrylates having an alkyl group of 1 to 12 carbon atoms, at least 1 selected from the group consisting of methyl (meth) acrylate, cyclohexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate and butyl (meth) acrylate is more preferable, and at least cyclohexyl (meth) acrylate is particularly preferable.

"acrylic resin" refers to the following resins: contains a structural unit derived from a (meth) acrylate ester, and the content of the structural unit derived from a (meth) acrylate ester is 20 to 99 mass% relative to the total amount of the structural units derived from the monomers constituting the resin. Among these, the structural unit derived from the (meth) acrylate preferably contains 1 or more structural units derived from an alkyl (meth) acrylate, the number of carbons of an alkyl group of the structural units derived from an alkyl (meth) acrylate is 1 to 12, more preferably 1 to 8, and even more preferably 1 to 6, and the total content of the structural units derived from an alkyl (meth) acrylate, the number of carbons of which is 1 to 12, more preferably 1 to 8, and even more preferably 1 to 6, relative to the total amount of the structural units derived from the monomers constituting the acrylic resin, is preferably 20 mass% or more, more preferably 50 mass% or more, even more preferably 70 mass%, and particularly preferably 90 mass%. Among these, an acrylic copolymer containing a structural unit derived from 2-ethylhexyl (meth) acrylate and/or a structural unit derived from cyclohexyl (meth) acrylate is more preferable, and the total content of structural units derived from these monomers is preferably 20% by mass or more, more preferably 50% by mass or more, even more preferably 70% by mass or more, and particularly preferably 90% by mass or more, based on the total amount of structural units derived from the monomers constituting the acrylic resin.

The surfactant having a polymerizable group is a surfactant having an unsaturated double bond and capable of polymerizing with another monomer. More specifically, for example, a surfactant having a radical polymerizable double bond such as a vinyl group, (meth) acryloyl group, allyl group, propenyl group, or the like in its molecule, which can be used as an emulsifier, is preferably used. When the surfactant is used as an emulsifier in the production of the acrylic resin, the emulsifier itself may be incorporated into the acrylic resin as a structural unit of the acrylic resin. Therefore, elution with time due to contact with water or the like after coating can be suppressed, and the water resistance of the coating film can be improved as compared with the case of using an emulsifier having no polymerizable group.

Examples of the surfactant having a polymerizable group include bis (polyoxyethylene polycyclic phenyl ether) methacrylated sulfonates (e.g., produced by Nippon emulsifier Co., Ltd., Antox (registered trademark) MS-60, etc.), allyl sulfosuccinate alkyl ester salts, polyoxyethylene (meth) acrylate sulfonates, polyoxyethylene (meth) acrylate phosphonates (e.g., produced by Sanyo chemical industries, Ltd., ELEMINOL (registered trademark) RS-30, etc.), polyoxyethylene alkylphenyl ether sulfonates (e.g., produced by first Industrial pharmaceutical Co., Ltd., Aqualon (registered trademark) HS-10, etc.), allyloxymethyl alkyloxy polyoxyethylene sulfonates (e.g., produced by first Industrial pharmaceutical Co., Ltd., Aqualon (registered trademark) KH-10, etc.), and allyloxymethyl nonylphenoxyethylhydroxypolyoxyethylene sulfonates (e.g., ADEKA (registered trademark) SE-10, manufactured by ADEKA K.K.), allyloxymethylalkoxyethyl hydroxypolyoxyethylene sulfate ester salt (e.g., ADEKA, ADERA REASOAP (registered trademark) SR-10, SR-30, etc.), allyloxymethylalkoxyethyl hydroxypolyoxyethylene (e.g., ADEKA, manufactured by ADERA REASOAP (registered trademark) ER-20, etc.), polyoxyethylene alkylphenyl ether (e.g., Aqualon (registered trademark) RN-20, manufactured by first Industrial pharmaceutical products Co., Ltd.), allyloxymethylnonylphenoxyethylpolyoxyethylene (e.g., ADEKA, manufactured by ADERA REA (registered trademark) NE-10, etc.), polyoxyethylene styrenated propenylphenyl ether sulfate ammonium salt (e.g., AR, manufactured by first Industrial pharmaceutical products K.K.), Aqualonon (registered trademark) 10, Azalon (registered trademark) sulfate salt (e.g., Azalon (registered trademark) SE-10, manufactured by first Industrial pharmaceutical products K.K., AR-20, AR-30, etc.), polyoxyethylene styrenated propenyl phenyl ether (e.g., Aqualon (registered trademark) AN-10, AN-20, AN-30, AN-5065, etc., manufactured by first Industrial pharmaceutical Co., Ltd.), etc. These may be used alone or in combination of 2 or more. When particular importance is attached to the environment, a non-nonylphenyl type surfactant is more preferably used.

The content of the structural unit derived from the polymerizable group-containing surfactant is more preferably 1.0 to 10% by mass, still more preferably 1.5 to 8.0% by mass, and particularly preferably 2.0 to 5.0% by mass, based on the total amount of the structural units derived from the monomers constituting the acrylic resin. The content of the structural unit derived from the surfactant is preferably 1.0 mass% or more, and thus polymerization stability is good. Further, the structural unit derived from the surfactant is preferably 10% by mass or less, and thus the water resistance of a coating film formed using the aqueous resin composition is less likely to decrease.

In one embodiment of the present invention, the acrylic resin may further contain a structural unit derived from an unsaturated carboxylic acid. By further containing a structural unit derived from an unsaturated carboxylic acid, the interaction between the acrylic resins can be improved. Therefore, a cohesive force can be imparted to the coating film formed from the aqueous resin composition, and adhesion and peel strength can be improved. Examples of the unsaturated carboxylic acid used as a monomer include (meth) acrylic acid, itaconic acid, crotonic acid, maleic anhydride, maleic acid, fumaric acid, citraconic acid, 2-acryloxyethylsuccinic acid, 2-acryloxyethylphthalic acid, and 2-acryloxyethylhexahydrophthalic acid, monomethyl maleate, monobutyl maleate, monomethyl itaconate, monobutyl itaconate, and vinylbenzoic acid. The unsaturated carboxylic acid is more preferably (meth) acrylic acid.

In one embodiment of the present invention, the content of the structural unit derived from the unsaturated carboxylic acid is preferably 0.4 to 8.0% by mass, more preferably 0.6 to 7.0% by mass, and particularly preferably 1.0 to 6.0% by mass, based on the total amount of the structural units derived from the monomers constituting the acrylic resin. The content of the structural unit derived from the unsaturated carboxylic acid is preferably 0.4% by mass or more, whereby the adhesiveness and the peel strength can be improved. Further, the content of the structural unit derived from the unsaturated carboxylic acid is preferably 8.0% by mass or less, whereby the water resistance can be improved.

In one embodiment of the present invention, the acrylic resin preferably contains a structural unit derived from a nitrogen atom-containing monomer. Examples of the nitrogen atom-containing monomer include a piperidyl-containing monomer such as 4- (meth) acryloyloxy-2, 2, 6, 6-tetramethylpiperidine, 4- (meth) acryloylamino-2, 2, 6, 6-tetramethylpiperidine, 4- (meth) acryloyloxy-1, 2, 2, 6, 6-pentamethylpiperidine, 4- (meth) acryloyl-1-methoxy-2, 2, 6, 6-tetramethylpiperidine, 4-cyano-4- (meth) acryloyloxy-2, 2, 6, 6-tetramethylpiperidine, 1- (meth) acryloyl-4- (meth) acryloylamino-2, 2, 6, 6-tetramethylpiperidine and the like; (meth) acrylamide compounds such as (meth) acrylamide, diacetone (meth) acrylamide, N-monomethyl (meth) acrylamide, N-monoethyl (meth) acrylamide, N-dimethyl (meth) acrylamide, N-propyl (meth) acrylamide, N-isopropyl (meth) acrylamide, methylenebis (meth) acrylamide, N-methylol (meth) acrylamide, N-butoxymethyl (meth) acrylamide, dimethylaminoethyl (meth) acrylamide, N-dimethylaminopropyl (meth) acrylamide, diacetone (meth) acrylamide, and the like; nitrogen atom-containing (meth) acrylate compounds such as dimethylaminoethyl (meth) acrylate and diethylaminoethyl (meth) acrylate; n-vinyl pyrrolidone; (meth) acrylonitrile, and the like. These nitrogen atom-containing monomers may be used alone or in combination of 2 or more.

Among these nitrogen atom-containing monomers, preferred are (meth) acrylamide compounds, (meth) acrylonitrile, and piperidyl group-containing monomers, more preferred are (meth) acrylamide, acrylonitrile, 4- (meth) acryloyloxy-2, 2, 6, 6-tetramethylpiperidine (LA-87), and 4- (meth) acryloyloxy-1, 2, 2, 6, 6-pentamethylpiperidine (LA-82), and still more preferred are acrylamide, acrylonitrile, 4- (meth) acryloyloxy-2, 2, 6, 6-tetramethylpiperidine (LA-87), and 4- (meth) acryloyloxy-1, 2, 2, 6, 6-pentamethylpiperidine (LA-82), from the viewpoint of forming a coating film having excellent cohesive force.

The content of the structural unit derived from the nitrogen atom-containing monomer is preferably 0.1 to 20% by mass, more preferably 0.1 to 15% by mass, and particularly preferably 0.1 to 10% by mass, based on the total amount of the structural units derived from the monomers constituting the acrylic resin. The content of the structural unit derived from the nitrogen atom-containing monomer is preferably 0.1 to 20% by mass, and thus a coating film having excellent cohesion can be formed.

In one embodiment of the present invention, the acrylic resin preferably contains a structural unit derived from a hydroxyl group-containing monomer from the viewpoint of improving peel strength and adhesion. Examples of the hydroxyl group-containing monomer include hydroxyalkyl (meth) acrylates such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, and 4-hydroxybutyl (meth) acrylate. These hydroxyl group-containing monomers may be used alone or in combination of 2 or more.

The content of the structural unit derived from the hydroxyl group-containing monomer is preferably 0.1 to 20% by mass, more preferably 0.1 to 15% by mass, and particularly preferably 0.1 to 10% by mass, based on the total amount of the structural units derived from the monomers constituting the acrylic resin. The content of the structural unit derived from the hydroxyl group-containing monomer is preferably 0.1 to 20% by mass, and thus a coating film excellent in peel strength and adhesion can be formed.

In one embodiment of the present invention, the acrylic resin preferably contains a structural unit derived from an alkoxyalkyl group-containing monomer, from the viewpoint of improving peel strength and adhesion. Examples of the alkoxyalkyl group-containing monomer include alkoxyalkyl (meth) acrylates such as methoxyethyl (meth) acrylate, methoxybutyl (meth) acrylate, ethoxybutyl (meth) acrylate, trimethylolpropane tripropoxy (meth) acrylate, and the like. These alkoxyalkyl group-containing monomers may be used alone or in combination of 2 or more.

The content of the structural unit derived from the alkoxyalkyl group-containing monomer is more preferably 0.1 to 20% by mass, still more preferably 0.1 to 15% by mass, and particularly preferably 0.1 to 10% by mass, based on the total amount of the structural units derived from the monomers constituting the acrylic resin. The content of the structural unit derived from the alkoxyalkyl group-containing monomer is preferably 0.1 to 20% by mass, and thus a coating film excellent in peel strength and adhesion can be formed,

in one embodiment of the present invention, the acrylic resin preferably contains a functional group α capable of reacting with a polyfunctional compound described later to form a crosslinked structure between particles of the aqueous dispersion. Examples of the functional group α include an alkoxycarbonyl group, a cyclocarbonate group, an epoxy group, an isocyanate group, a blocked isocyanate group, an oxazoline group, an oxazolidine group, an acetoacetoxy group, a hydrazine group, and a carbonyl group, but the present invention is not limited to these examples. These functional groups may be used alone or in combination of 2 or more. Among these functional groups, an epoxy group, an isocyanate group, an oxazoline group, a hydrazine group and a carbonyl group are preferable, an oxazoline group, a hydrazine group and a carbonyl group are more preferable, and a carbonyl group is further preferable. For example, the acrylic resin containing the functional group α may be obtained by copolymerizing a monomer containing the functional group α.

In one embodiment of the present invention, the carbonyl group-containing monomer refers to the following monomers: has a group represented by the formula "═ C ═ O", and 1 bonding bond among 2 bonding bonds of the carbonyl group is bonded to a hydrogen atom or an alkyl group, and the other 1 bonding bond is bonded to a group having a polymerizable unsaturated double bond at the terminal, such as a vinyl group.

Examples of the carbonyl group-containing monomer (hereinafter, also referred to as "carbonyl group-containing monomer") include acrolein, methacrolein, formylstyrene, vinyl ethyl ketone, acryloxyalkyl acrolein, methacryloxyalkyl acrolein, propyl acrylate, propyl methacrylate, bis-propyl acrylate, bis-propyl methacrylate, bis-acetone acrylamide, bis-acetone methacrylamide, 2-hydroxypropyl acetoacetate acrylate, 2-hydroxypropyl acetoacetate methacrylate, 1, 4-butanediol acetoacetate acrylate, 2- (acetoacetoxy) ethyl acrylate, and 2- (acetoacetoxy) ethyl methacrylate. These carbonyl group-containing monomers may be used alone or in combination of 2 or more.

From the viewpoint of forming a coating film having superior water whitening resistance, water crack resistance, water deformation resistance, weather resistance and long-term hydrophilicity as a whole, among the carbonyl group-containing monomers, (meth) acrolein, formylstyrene, vinyl ethyl ketone, (meth) acryloyloxyalkyl acrolein, methyl acrylate, diacetone (meth) acrylate and diacetone (meth) acrylamide are preferable, and (meth) acrolein, methyl acrylate, formyl styrene, propyl (meth) acrylate, diacetone (meth) acrylate and diacetone (meth) acrylamide are more preferable, and (meth) acrolein, methyl acrylate, diacetone (meth) acrylate and diacetone (meth) acrylamide are further preferable, and diacetone (meth) acrylate and diacetone (meth) acrylamide are further more preferable.

The content of the structural unit derived from the functional group α -containing monomer is preferably 0.1 to 20% by mass, more preferably 0.1 to 15% by mass, and particularly preferably 0.1 to 10% by mass, based on the total amount of the structural units derived from the monomers constituting the acrylic resin. The content of the structural unit derived from the carbonyl group-containing monomer is preferably 0.1 to 20% by mass, for example, whereby a coating film excellent in all of water whitening resistance, water cracking resistance, water deformation resistance, weather resistance and long-term hydrophilicity can be formed.

In one embodiment of the present invention, the acrylic resin preferably contains a structural unit derived from a silane group-containing monomer.

Examples of the silane group-containing monomer include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (methoxyethoxy) silane, γ - (meth) acryloyloxypropyltrimethoxysilane, 2-styrylethyltrimethoxysilane, vinyltrichlorosilane, γ - (meth) acryloyloxypropylhydroxysilane, γ - (meth) acryloyloxypropylmethylhydroxysilane, and the like. These silane group-containing monomers may be used alone or in combination of 2 or more. Among these silane group-containing monomers, γ - (meth) acryloyloxypropyltrimethoxysilane is preferable, and γ -methacryloyloxypropyltrimethoxysilane is more preferable, from the viewpoint of forming a coating film excellent in water resistance, blister resistance and adhesion to a substrate.

The content of the structural unit derived from the silane group-containing monomer is more preferably 0.01 to 10% by mass, still more preferably 0.05 to 10% by mass, and particularly preferably 0.1 to 10% by mass, based on the total amount of the structural units derived from the monomers constituting the acrylic resin. The content of the structural unit derived from the silane group-containing monomer is preferably 0.01 to 10% by mass, and thus a coating film having excellent water resistance, blister resistance, and adhesion to a substrate can be formed.

The acrylic resin may contain a structural unit derived from another monomer within a range not adversely affecting the effect of the present invention, in addition to the structural unit derived from the (meth) acrylate and the structural unit derived from the surfactant having a polymerizable group, and if necessary, the structural unit derived from the unsaturated carboxylic acid, the structural unit derived from the nitrogen atom-containing monomer, the structural unit derived from the hydroxyl group-containing monomer, the structural unit derived from the functional group α -containing monomer, and/or the structural unit derived from the silane group-containing monomer. Examples of the other monomer include styrene. The content of the structural unit derived from the other monomer is preferably in the range of 0 to 70% by mass relative to the total amount of the structural units derived from the monomers constituting the acrylic resin.

In one embodiment of the present invention, the acrylic resin may be a resin which is produced through a series of production steps (for example, multistage polymerization) and contains 2 or more kinds of polymer chains and is formed by compounding the 2 or more kinds of polymer chains. In this case, at least 1 kind of the polymer chain of the acrylic resin may include the structural unit derived from the (meth) acrylate and the structural unit derived from the surfactant having a polymerizable group, but from the viewpoint of water resistance, it is more preferable that 2 or more kinds of the polymer chains each include the structural unit derived from the (meth) acrylate and the structural unit derived from the surfactant having a polymerizable group.

The resin composed of 2 or more kinds of polymer chains may have a homogeneous structure in which one polymer chain and the other polymer chain are completely compatible and cannot be distinguished from each other, or may have a heterogeneous structure (for example, a core-shell structure or a micro domain structure) in which one polymer chain and the other polymer chain are not completely compatible. Of these structures, for example, a core-shell composite structure is more preferable from the viewpoint of producing a stable dispersion.

In one embodiment of the present invention, the acrylic resin has a core section and a shell section, and examples thereof include an acrylic resin containing 2 types of polymer chains, one of the 2 types of polymer chains forming the core section and the other forming the shell section.

The core-shell composite structure is preferably such that the surface of the core portion is covered with the shell portion. In this case, the surface of the core portion is preferably completely covered by the shell portion, but may not be completely covered. For example, it may be a textured overlay or the core may be partially exposed.

The method for producing the acrylic resin having the core-shell structure is not particularly limited, and a preferred method is to perform multistage emulsion polymerization, form a core portion in the 1 st stage, and then perform emulsion polymerization in the 2 nd stage on the core portion to form a shell portion.

When the acrylic resin is a core-shell composite structure resin, the mass ratio of the core portion to the shell portion (core portion/shell portion) is preferably 1/99 to 99/1. More preferably 5/95 to 95/5, and still more preferably 10/90 to 90/10.

In the case where the acrylic resin has a core-shell composite structure, at least one of the polymer chain for forming the core portion and the polymer chain for forming the shell portion may contain the structural unit derived from the (meth) acrylate and the structural unit derived from the surfactant having a polymerizable group, and more preferably, both the polymer chain for forming the core portion and the polymer chain for forming the shell portion contain the structural unit derived from the (meth) acrylate and the structural unit derived from the surfactant having a polymerizable group.

When both the polymer chain for forming the core portion and the polymer chain for forming the shell portion include the structural unit derived from the (meth) acrylate and the structural unit derived from the surfactant having a polymerizable group, it is more preferable that the core portion further includes at least 1 of the structural unit derived from the unsaturated carboxylic acid, the structural unit derived from the hydroxyl group-containing monomer, and the structural unit derived from the nitrogen atom-containing monomer. Further, it is more preferable that the shell portion further contains at least 1 of a structural unit derived from an alkoxyalkyl group-containing monomer, a structural unit derived from a nitrogen atom-containing monomer, a structural unit derived from a silyl group-containing monomer, a structural unit derived from a hydroxyl group-containing monomer, and a structural unit derived from an unsaturated carboxylic acid.

When one of the polymer chain for forming the core portion and the polymer chain for forming the shell portion contains the structural unit derived from the (meth) acrylate and the structural unit derived from the surfactant having a polymerizable group, the other polymer chain is not particularly limited, and the structural unit derived from the (meth) acrylate and 1 or 2 or more other copolymerizable unsaturated bond-containing monomers can be used.

In one embodiment of the present invention, the acrylic resin may include 1 or 2 or more of the above acrylic resins.

The weight average molecular weight of the acrylic resin is not limited, but is preferably 10 to 500 ten thousand, and more preferably 30 to 300 ten thousand, from the viewpoint of adhesion of the formed coating film.

The glass transition temperature Tg (hereinafter, also simply referred to as "Tg") of the acrylic resin is preferably 0 to 60 ℃, and more preferably 10 to 40 ℃. Here, Tg can be calculated by the following method.

The glass transition temperature Tg of the acrylic resin can be found by the arithmetic Tg (k) calculated by the following Fox equation.

1/Tg＝Σ(Wn/Tgn)/100

Here, Wn is the content (mass%) of the monomer n, and Tgn is the Tg (K: absolute temperature) of a homopolymer composed of the monomer n.

In addition, when at least 1 of the acrylic resins is obtained by multistage polymerization (for example, in the case of resin particles having a core portion and a shell portion), the glass transition temperature Tg is calculated from monomers used in all stages.

The acrylic resin preferably has a Tg of 0 ℃ or higher, so that the adhesion, peel strength and water resistance of the formed coating film can be improved. The acrylic resin preferably has a Tg of 60 ℃ or less, so that even when the resin composition (or coating material) according to an embodiment of the present invention is applied to a substrate and dried (for example, dried by heating in an air jet oven at 80 ℃ described later), the dried coating film can be molded into a film without causing chipping or cracking. Further, the Tg of the acrylic resin is more preferably 10 ℃ or higher from the viewpoint of improving the peel strength of the formed coating film.

In one embodiment of the present invention, the method for producing the acrylic resin is not limited, and a preferable method is emulsion polymerization using the (meth) acrylate and optionally the unsaturated carboxylic acid, the nitrogen atom-containing monomer, the hydroxyl group-containing monomer, the functional group α -containing monomer, the silane group-containing monomer, and/or the other monomer as monomers in the presence of a surfactant that functions as an emulsifier and has the polymerizable group. By emulsion polymerization, an aqueous dispersion of acrylic resin particles (also referred to as an acrylic resin emulsion) can be formed.

The emulsion polymerization to be carried out here is not particularly limited, and conventionally known methods such as a multistage feeding method and a dynamic feeding method can be used. Specifically, the following methods (1) and (2) can be used. In this case, the above-mentioned surfactant having a polymerizable group can be used as the emulsifier.

Method (1): dissolving an emulsifier in an aqueous medium, and dropping the (meth) acrylate and a polymerization initiator, and optionally dropping the unsaturated carboxylic acid, the nitrogen atom-containing monomer, the hydroxyl group-containing monomer, the functional group α -containing monomer, the silane group-containing monomer, and/or the other monomer to the aqueous medium while heating and stirring.

Method (2): the (meth) acrylate, and optionally the unsaturated carboxylic acid, the nitrogen atom-containing monomer, the hydroxyl group-containing monomer, the functional group α -containing monomer, the silane group-containing monomer, and/or the other monomer are emulsified in advance with an emulsifier and an aqueous medium, and then the emulsified product and a polymerization initiator are added dropwise to the aqueous medium while heating and stirring.

The polymerization initiator is not particularly limited, and examples thereof include azo compounds such as 2, 2-azobis (2-diaminopropane) hydrochloride; persulfates such as potassium persulfate; peroxides such as hydrogen peroxide, and the like. Specific examples thereof include azo-based oily compounds (e.g., azobisisobutyronitrile, 2-azobis (2-methylbutyronitrile), 2-azobis (2, 4-dimethylvaleronitrile), etc.), aqueous compounds (e.g., anionic 4, 4-azobis (4-cyanovaleric acid), cationic 2, 2-azobis (2-methylpropionamidine)); redox-type oily peroxides (e.g., benzoyl peroxide, p-chlorobenzoyl peroxide, lauroyl peroxide, t-butyl peroxybenzoate, etc.), aqueous peroxides (e.g., potassium persulfate, ammonium peroxide, etc.), and the like. In addition, the polymerization initiator can be used only 1 kind or more than 2 kinds.

The amount of the polymerization initiator used is not particularly limited, and is preferably 0.05 to 1% by mass, more preferably 0.1 to 0.5% by mass, based on the total amount of the monomer components. When the amount of the polymerization initiator used is 0.05% by mass or more, a preferable polymerization rate can be obtained, and therefore, the monomer is less likely to remain, and when the amount of the polymerization initiator used is 1% by mass or less, the water resistance of the formed coating film is good.

The method of addition is not particularly limited, and for example, all-at-one addition, addition in portions, continuous dropwise addition and the like may be used. In order to promote completion of the polymerization, a part of the polymerization initiator may be added before and after completion of dropping of the polymerizable monomer component in the final stage.

In the emulsion polymerization, a reducing agent such as sodium hydrogen sulfite and/or a transition metal salt such as ferrous sulfate may be added to accelerate the decomposition of the polymerization initiator. In the emulsion polymerization, known additives such as a pH buffer, a chelating agent, a chain transfer agent, and a film-forming aid may be added as necessary. Examples of the chain transfer agent include a compound having a thiol group such as t-dodecyl mercaptan. The amount of the chain transfer agent and the regulator to be used is not particularly limited, and may be, for example, 0.01 to 5% by mass, and more preferably 0.1 to 3% by mass, based on the total amount of the monomer components.

The polymerization temperature in the polymerization step is not particularly limited, but is preferably 0 to 100 ℃, and more preferably 40 to 95 ℃. The polymerization temperature may be constant, or may be changed during the polymerization or at various stages. The polymerization time is not particularly limited, and may be appropriately set according to the progress of the reaction, and for example, the time from the start to the end of the polymerization is preferably in the range of 2 to 8 hours. In order to improve the efficiency of the polymerization initiator, the atmosphere during polymerization is preferably an inert gas atmosphere such as nitrogen.

In addition, as the emulsifier used in the emulsion polymerization, in addition to the above-mentioned surfactant having a polymerizable group, a surfactant having no polymerizable group may be used in combination. As the surfactant having no polymerizable group, an anionic surfactant having no polymerizable group, a nonionic surfactant having no polymerizable group, a cationic surfactant having no polymerizable group, an amphoteric surfactant having no polymerizable group, a polymer surfactant having no polymerizable group, and the like can be used. These surfactants may be used alone in 1 kind or in combination with 2 or more kinds.

Examples of the anionic surfactant having no polymerizable group include alkyl sulfates such as ammonium lauryl sulfate and sodium lauryl sulfate; alkyl sulfonates such as ammonium dodecylsulfonate and sodium dodecylsulfonate; alkyl aryl sulfonates such as ammonium dodecylbenzenesulfonate and sodium dodecylnaphthalenesulfonate; polyoxyethylene alkyl sulfates; polyoxyethylene alkylaryl sulfates; a dialkyl sulfosuccinate salt; an arylsulfonic acid formalin condensate; fatty acid salts such as ammonium laurate and sodium stearate; and the like. Examples of the non-polymerizable group-free nonionic surfactant include polyoxyethylene alkyl ethers; polyoxyethylene alkyl aryl ethers; a condensate formed from polyethylene glycol and polypropylene glycol; sorbitan esters of fatty acids; polyoxyethylene sorbitan esters of fatty acids; a fatty acid monoglyceride; a polyamide; a condensation product formed from ethylene oxide and an aliphatic amine; and the like. Examples of the cationic surfactant having no polymerizable group include alkylammonium salts such as dodecylammonium chloride; and the like. Examples of the amphoteric surfactant having no polymerizable group include betaine ester type emulsifiers; and the like. Examples of the polymeric surfactant having no polymerizable group include poly (meth) acrylates such as sodium polyacrylate; polyvinyl alcohol; polyvinylpyrrolidone; polyhydroxyalkyl (meth) acrylates such as polyhydroxyethyl acrylate; or a copolymer containing 1 or more of these polymerizable monomers constituting the polymer as a copolymerization component; and the like.

The amount of the surfactant having no polymerizable group is not particularly limited, and is preferably 0 to 5% by mass, more preferably 0 to 3% by mass, even more preferably 0 to 1% by mass, and most preferably substantially 0% by mass, based on the total amount of the monomer components, from the viewpoint of not reducing both the water resistance and the polymerization stability of the coating film. Therefore, when the reaction liquid obtained by the emulsion polymerization using the surfactant having no polymerizable group in combination is directly used as the acrylic resin aqueous dispersion (B), the content of the surfactant having no polymerizable group in the acrylic resin aqueous dispersion (B) is preferably 0 to 5% by mass, more preferably 0 to 3% by mass, and still more preferably 0 to 1% by mass, based on the total amount of the acrylic resin. The content may be substantially 0% by mass.

The average particle diameter of the acrylic resin particles in the acrylic resin aqueous dispersion (acrylic resin emulsion) (B) is preferably 40nm to 300nm, more preferably 50nm to 200 nm. In the present specification, the average particle diameter refers to an average particle diameter measured by the method described in examples.

In one embodiment of the present invention, the acrylic resin may be mixed with the polyolefin aqueous dispersion (a) in the form of an acrylic resin aqueous dispersion (B) comprising: an acrylate resin obtained by emulsion polymerization of a monomer for an acrylic resin, the acrylate resin containing a structural unit derived from a surfactant having a polymerizable group; and an aqueous medium. The acrylic resin aqueous dispersion (B) contains the acrylic resin and an aqueous medium.

The content of the acrylic resin in the acrylic resin aqueous dispersion (B) may be appropriately adjusted depending on the aqueous resin composition and primer composition to be finally obtained, and is preferably 15 to 60% by mass, more preferably 20 to 50% by mass, based on the acrylic resin aqueous dispersion (B). The amount of the solid content in the acrylic resin aqueous dispersion (B) is preferably 10 to 50% by mass, and more preferably 15 to 40% by mass. In the present specification, the amount of the solid component refers to an amount measured by the method described in the examples below.

The reaction liquid obtained in the emulsion polymerization can be used as it is as the acrylic resin aqueous dispersion (B).

From the viewpoint of stability of the dispersion, the pH of the acrylic resin aqueous dispersion (B) is preferably 5 to 10, more preferably 6 to 9.5, and still more preferably 7 to 9.5. If the pH is less than 5, the stability and physical stability of the emulsion may be lowered. If the pH exceeds 10, problems in practicality such as reduction in water resistance or generation of odor may occur.

Any suitable pH adjusting agent may be used to adjust the pH of the acrylic resin aqueous dispersion (B) to the above range. Specific examples of the pH adjuster include alkali metal compounds such as sodium hydroxide and potassium hydroxide; alkaline earth metal compounds such as calcium hydroxide and calcium carbonate; ammonia; and water-soluble organic amines such as dimethylaminoethanol, monomethylamine, dimethylamine, trimethylamine, monoethylamine, diethylamine, triethylamine, monopropylamine, dimethylpropylamine, monoethanolamine, diethanolamine, triethanolamine, ethylenediamine, and diethylenetriamine. These pH adjusters may be used alone or in combination of 2 or more.

[ 1.3 crosslinking agent ]

The aqueous resin composition according to an embodiment of the present invention may include a crosslinking agent capable of reacting with the non-chlorinated polyolefin having a carboxyl group, the carboxyl group contained in the acrylic resin, and the functional group α. Examples of the crosslinking agent capable of reacting with a carboxyl group include oxazoline group-containing compounds, carbodiimide group-containing compounds, epoxy group-containing compounds, and the like, and a plurality of these may be used in combination as necessary.

The oxazoline group-containing compound is not particularly limited as long as it has at least 2 oxazoline groups in its molecule. Examples thereof include compounds having an oxazoline group such as 2, 2 '-bis (2-oxazoline), 2' -ethylene-bis (4, 4 '-dimethyl-2-oxazoline), 2' -p-phenylenebis (2-oxazoline), and thiobis (2-oxazolinylcyclohexane), and polymers having an oxazoline group. These may be used in 1 or 2 or more. Among these, oxazoline group-containing polymers are preferable because of their easy handling.

The oxazoline group-containing polymer is usually obtained by polymerizing oxazoline having addition polymerizability, such as 2-vinyl 2-oxazoline, 2-vinyl 4-methyl-2-oxazoline, 2-isopropenyl-2-oxazoline or the like. The oxazoline group-containing polymer may be copolymerized with other monomers, if necessary. The polymerization method of the oxazoline group-containing polymer is not particularly limited, and a known polymerization method can be used.

Examples of commercially available oxazoline group-containing polymers include Epocros (registered trademark) series produced by Nippon catalyst K.K., and examples thereof include "WS-500" and "WS-700" which are water-soluble types; emulsion types "K-1010E", "K-1020E", "K-1030E", "K-2010E", "K-2020E", "K-2030E", and the like.

The carbodiimide group-containing compound may have at least 2 carbodiimide groups in its molecule, and is not particularly limited. Examples thereof include compounds having a carbodiimide group such as p-phenylenebis (2, 6-xylylcarbodiimide), tetramethylene-bis (t-butylcarbodiimide), and cyclohexane-1, 4-bis (methylene-t-butylcarbodiimide), and polycarbodiimides which are polymers having a carbodiimide group. These may be used in 1 or 2 or more. Among these, polycarbodiimides are preferable because of their ease of handling.

Examples of commercially available polycarbodiimides include CARBODILITE (registered trademark) series manufactured by Nisshinbo textile, Inc. Specific examples of the commercial products include water-soluble types "SV-02", "V-02-L2", "V-04"; emulsion type "E-01", "E-02"; "V-01", "V-03", "V-07", "V-09" of the organic solution type; solvent-free type "V-05", and the like.

The epoxy group-containing compound is not particularly limited as long as it has at least 2 epoxy groups in its molecule. Examples thereof include glycidyl ether types such as bisphenol a diglycidyl ether, bisphenol a β -dimethyl glycidyl ether, bisphenol F diglycidyl ether, tetrahydroxyphenylmethane tetraglycidyl ether, resorcinol diglycidyl ether, brominated bisphenol a diglycidyl ether, chlorinated bisphenol a diglycidyl ether, hydrogenated bisphenol a diglycidyl ether, bisphenol a alkylene oxide adduct diglycidyl ether, phenol novolac glycidyl ether, polyalkylene glycol diglycidyl ether, glycerol triglycidyl ether, pentaerythritol diglycidyl ether, and epoxy urethane resins; glycidyl ether ester types such as glycidyl ether ester of paraoxybenzoic acid; glycidyl ester types such as diglycidyl phthalate, diglycidyl tetrahydrophthalate, diglycidyl hexahydrophthalate, diglycidyl acrylate, and diglycidyl dimer acid; glycidyl amine types such as glycidylaniline, tetraglycidyldiaminodiphenylmethane, triglycidyl isocyanurate, triglycidyl aminophenol and the like; chain aliphatic epoxy resins such as epoxidized polybutadiene and epoxidized soybean oil; alicyclic epoxy resins such as 3, 4-epoxy-hexamethylcyclohexylmethyl-3, 4-epoxy-hexamethylcyclohexanecarboxylate, 3, 4-epoxycyclohexylmethyl (3, 4-epoxycyclohexane) formate, bis (3, 4-epoxy-hexamethylcyclohexylmethyl) adipate, diepoxide of vinylcyclohexene, epoxide of dicyclopentadiene, bis (2, 3-epoxycyclopentyl) ether, and diepoxide of limonene, and the like. These may be used in 1 or 2 or more.

As the commercially available epoxy compound, examples of the aqueous epoxy compound suitable for use in the present invention include DENANOL (registered trademark) series (EM-150, EM-101, etc.) manufactured by Karmax corporation, ADEKA RESIN (registered trademark) series manufactured by ADEKA corporation, and the like, and polyfunctional epoxy resin emulsions such as ADEKA RESIN (registered trademark) EM-0517, EM-0526, EM-11-50B, EM-051R, etc., manufactured by ADEKA corporation are preferable from the viewpoint of improving UV paint adhesion and scratch resistance.

The content of the crosslinking agent is preferably 0.1 to 5% by mass, more preferably 0.5 to 2% by mass, based on the amount of solid components in the aqueous resin composition, more preferably based on the total amount of solid components of the non-chlorinated polyolefin having a carboxyl group and the acrylic resin contained in the aqueous resin composition. The content of the crosslinking agent is preferably 0.1 to 5% by mass, whereby the adhesion of the formed coating film can be improved.

Alternatively, the aqueous resin composition according to an embodiment of the present invention preferably contains a polyfunctional compound which is a crosslinking agent capable of reacting with the functional group α. The polyfunctional compound preferably includes a hydrazine group-containing crosslinking agent, the hydrazine group-containing crosslinking agent preferably contains 2 or more groups of at least 1 group selected from a carboxyl group, a hydrazine group, an oxazoline group and an epoxy group, and the polyfunctional compound preferably has 2 or more hydrazine groups.

Examples of the hydrazine group-containing crosslinking agent include aliphatic water-soluble dihydrazides having 2 to 4 carbon atoms such as oxalic acid dihydrazide, malonic acid dihydrazide, succinic acid dihydrazide, glutaric acid dihydrazide, adipic acid dihydrazide, sebacic acid dihydrazide, maleic acid dihydrazide, fumaric acid dihydrazide and itaconic acid dihydrazide, ethylene-1, 2-dihydrazide, propylene-1, 3-dihydrazide and butylene-1, 4-dihydrazide. These hydrazine group-containing compounds may be used alone or in combination of 2 or more. Among these hydrazine group-containing crosslinking agents, dicarboxylic dihydrazides having 4 to 6 carbon atoms such as adipic dihydrazide, sebacic dihydrazide, maleic dihydrazide, fumaric dihydrazide, itaconic dihydrazide, succinic dihydrazide and glutaric dihydrazide are preferable, and adipic dihydrazide is more preferable, from the viewpoint of adhesion of the formed coating film.

The content of the polyfunctional compound such as the hydrazine group-containing crosslinking agent is preferably 0.1 to 5% by mass, more preferably 0.5 to 2% by mass, based on the amount of solid components in the aqueous resin composition, more preferably based on the total amount of solid components of the non-chlorinated polyolefin having a carboxyl group and the acrylic resin contained in the aqueous resin composition. The content of the crosslinking agent is preferably 0.1 to 5% by mass, whereby the adhesion of the formed coating film can be improved.

Among them, the hydrazine group-containing crosslinking agent is preferably a crosslinking agent capable of reacting with a carbonyl group, and is preferably used in combination with an acrylic resin containing a structural unit derived from a carbonyl group-containing monomer.

In addition, the aqueous resin composition according to an embodiment of the present invention may contain an acid-type catalyst such as p-toluenesulfonic acid, phosphoric acid, hydrochloric acid, or ammonium chloride, if necessary, in order to further promote crosslinking. The content of the crosslinking accelerator is 10 to 50% by mass relative to the crosslinking agent.

[ 1.4 aqueous resin composition ]

An aqueous resin composition according to an embodiment of the present invention includes: the non-chlorinated polyolefin having a carboxyl group, the acrylic resin, and an aqueous medium. Alternatively, the aqueous resin composition according to an embodiment of the present invention may include: an aqueous polyolefin dispersion (A) comprising an aqueous medium and a non-chlorinated polyolefin having a carboxyl group; and an acrylic resin aqueous dispersion (B) containing an acrylic resin and an aqueous medium, wherein the acrylic resin is obtained by emulsion polymerization of a monomer and contains a structural unit derived from a surfactant having a polymerizable group.

The lower the chlorine content in the carboxyl group-containing chlorinated polypropylene random copolymer, the better the adhesion to olefin substrates, but if the chlorine content is too low, the softening point and melting point of the resin increase, and therefore the adhesion during glazing at low temperatures decreases. In this way, replacing the aqueous dispersion of chlorinated polyolefin with the aqueous dispersion of non-chlorinated polyolefin reduces the adhesion at the time of glazing at low temperature, which is a conventional problem. In order to solve the above problem, an aqueous resin composition according to an embodiment of the present invention includes: a non-chlorinated polyolefin having a carboxyl group; an acrylic resin containing a structural unit derived from a surfactant having a polymerizable group; and an aqueous medium.

In one embodiment of the present invention, the aqueous resin composition may contain the non-chlorinated polyolefin having a carboxyl group, the acrylic resin, and an aqueous medium, and may further contain the crosslinking agent as needed.

Further, the aqueous resin composition may contain, for example, a thickener, a pigment dispersant, an antifoaming agent, an inorganic filler, a surfactant, a neutralizing agent, a stabilizer, a thickener, a surface conditioner, a leveling agent, an ultraviolet absorber, an antioxidant, conductive carbon, a conductive filler such as metal powder, an organic modifier, and a plasticizer, as necessary.

The content of the non-chlorinated polyolefin having a carboxyl group in the aqueous resin composition is preferably 2 to 48% by mass, and more preferably 4 to 32% by mass, based on the aqueous resin composition.

The content of the acrylic resin in the aqueous resin composition is preferably 2 to 48% by mass, and more preferably 4 to 32% by mass, based on the aqueous resin composition.

In addition, the content ratio of the non-chlorinated polyolefin having a carboxyl group and the acrylic resin in the aqueous resin composition is preferably 10: 90 to 70: 30, and more preferably 20: 80 to 60: 40 on a mass basis. When the content ratio is within the above range, an aqueous resin composition having excellent adhesion to a polyolefin substrate and excellent peel strength can be obtained.

The amount of the solid content in the aqueous resin composition is preferably 10 to 60% by mass, more preferably 20 to 40% by mass.

Further, the pH of the aqueous resin composition is preferably 5 to 10, more preferably 6 to 9.5, and still more preferably 7 to 9.5, from the viewpoint of improving the stability of the aqueous resin composition dispersion. If the pH is less than 5, the stability and physical stability of the aqueous resin composition may be lowered. If the pH exceeds 10, problems in practicality such as reduction in water resistance or generation of odor may occur.

Further, the average particle diameter of the non-chlorinated polyolefin having a carboxyl group and the acrylic resin contained in the aqueous resin composition as a whole is preferably 40nm to 300nm, and more preferably 50nm to 200 nm.

[ 2. utilization of aqueous resin composition ]

The aqueous resin composition according to one embodiment of the present invention is excellent in adhesion to a polyolefin substrate, and therefore can be used as an aqueous primer composition for a polyolefin substrate. Therefore, the present invention also includes a water-borne base coating composition containing the above-described water-borne resin composition.

The water-based primer composition according to one embodiment of the present invention is applied to a polyolefin substrate such as polyethylene, polypropylene, and TPO (thermoplastic olefin; thermoplastic olefin resin), and dried to form a primer layer on the polyolefin substrate. The drying temperature is not particularly limited, but if the water-based primer composition contains a crosslinking agent, a crosslinking reaction occurs during heat drying, and therefore, it is preferable to dry at a temperature at which the crosslinking reaction rapidly proceeds, depending on the kind of the crosslinking agent. For the film formation, conventionally known methods can be used, for example, gravure roll coating, reverse roll coating, wire bar coating, splash coating, air blade coating, curtain flow coating, spray coating, dip coating, brush coating, and the like.

The molded article according to an embodiment of the present invention is preferably: the polyolefin substrate or the polyolefin molded product has the primer layer and 1 or more exterior coatings on the primer layer.

Examples of the top coat layer include coating films obtained by applying a one-pack melamine glaze, a two-pack urethane coating, a one-pack clear coating, a bright coating, a high-hardness clear coating, and the like. When the exterior coating film has a multilayer structure of 2 or more layers, for example, a multilayer structure including a base coating film and a clear coating film is exemplified.

Examples of the polyolefin molded article include bumpers, moldings, fenders, mirror frames, grilles, and parts of household electric appliances of vehicles.

[ 3. Process for producing aqueous resin composition ]

The aqueous resin composition according to an embodiment of the present invention can be produced by mixing the non-chlorinated polyolefin having a carboxyl group, an acrylic resin containing a structural unit derived from a surfactant having a polymerizable group, an aqueous medium, and optionally other components.

The method for producing an aqueous resin composition according to one embodiment of the present invention more preferably includes a step of preparing an olefin aqueous dispersion (a) containing a non-chlorinated polyolefin having a carboxyl group and an aqueous medium and an acrylic resin aqueous dispersion (B) obtained by emulsion polymerization of a monomer constituting an acrylic resin in the presence of a surfactant having a polymerizable group in advance and mixing them.

An embodiment of the present invention may be as follows.

[ 1] an aqueous resin composition comprising: a non-chlorinated polyolefin having a carboxyl group; an acrylic resin containing a structural unit derived from a surfactant having a polymerizable group; and an aqueous medium.

The aqueous resin composition according to [ 1], wherein the content of the structural unit derived from the polymerizable group-containing surfactant is 1 to 10% by mass based on the total amount of the structural units derived from the monomers constituting the acrylic resin.

The aqueous resin composition according to [ 1] or [ 2], wherein the aqueous resin composition contains 0 to 5 mass% of a surfactant having no polymerizable group relative to the acrylic resin.

The aqueous resin composition according to any one of [ 1] to [ 3], wherein the acrylic resin further contains a structural unit derived from an unsaturated carboxylic acid.

[ 5] the aqueous resin composition according to any one of [ 1] to [ 4], which contains a crosslinking agent capable of reacting with a carboxyl group.

[ 6] an aqueous primer composition which comprises the aqueous resin composition according to any one of [ 1] to [ 5] and is suitable for polyolefin substrates.

[ 7] A molded article comprising the aqueous primer composition according to [ 6 ].

A method for producing an aqueous resin composition, comprising a step of mixing an aqueous polyolefin dispersion (a) and an aqueous acrylic resin dispersion (B), wherein the aqueous polyolefin dispersion (a) contains an aqueous medium and a non-chlorinated polyolefin having a carboxyl group, and the aqueous acrylic resin dispersion (B) is obtained by emulsion polymerization of a monomer in the presence of a surfactant having a polymerizable group.

Examples

Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to these examples. In the following examples, "part" means "part by mass".

[ measurement method ]

The Tg, melting point and average particle diameter of the acrylic resin particles obtained in production examples 1 and 2, and the solid content, pH and average particle diameter of all the resin particles contained in the acrylic resin aqueous dispersions obtained in production examples 1 and 2 and the aqueous resin compositions obtained in examples and comparative examples were measured by the following methods.

(1) Average particle diameter

The volume average particle diameter was measured using a particle size distribution measuring instrument (manufactured by tsukamur electronics corporation, "FPAR-1000").

(2)Tg

Based on the monomer components, the above Fox formula is used for calculation.

(3) Melting Point

The melting point was measured from the highest temperature of the melting peak and the area of the melting peak at the time of melting again at an elevated temperature after melting at an elevated temperature at a rate of 20 ℃/min using a differential scanning calorimeter (hereinafter, also referred to as "DSC". TA Instruments, Japan K.K. "Q-2000").

(4) Amount of solid component

1g of each of the acrylic resin aqueous dispersions and each of the aqueous resin compositions were weighed and dried in a hot air dryer at 110 ℃ for 1 hour, and the amount of the dry residue was taken as the amount of solid components, and the ratio (in mass%) of the amount of the dry residue to the mass before drying was calculated.

(5)pH

The pH value at 25 ℃ was measured with a pH meter ("F-23" manufactured by horiba, Ltd.).

[ evaluation method ]

The aqueous resin compositions obtained in examples and comparative examples were evaluated by the following methods.

(preparation of coating for evaluation)

To 100 parts of each aqueous resin composition, 4 parts of dipropylene glycol n-butyl ether (model: DOWANOL (registered trademark) DPnB, manufactured by Dow Chemical Co., Ltd.) as a film-forming aid and 1 part of a wetting agent (trade name: OLFINE (registered trademark) EXP.4200, manufactured by Nikken Chemical Co., Ltd.) were added, and the mixture was stirred with a homomixer at 1500 times/minute for 10 minutes to prepare a coating material for evaluation.

(preparation of coating film for evaluation)

The coating material for evaluation was applied to a polypropylene plate (manufactured by Japanese Testpanel Co., Ltd., length: 70mm, width: 150mm, thickness: 2mm) by using a bar coater (No. 14). The applied coating material for evaluation was dried in an air jet oven at an air speed of 3m and 80 ℃ for 15 minutes to form a coating film for evaluation having a film thickness of 10. + -. 2 μm on the polypropylene plate, thereby producing a test plate.

(1) Evaluation of initial adhesion (lattice test)

(test method)

A cross cut test was carried out in accordance with JIS K5600-5-6 using a test plate having a coating film for evaluation formed thereon.

Specifically, the coating film for evaluation was cut into a 2 mm-square 25-mesh grid (long: 5 grid, wide: 5 grid) with a sharp blade. Then, a 25mm wide scotch tape (Nichiban CT-24) was rubbed with a finger so as to be brought into close contact with the latticed cut portion. Then, the coating film for evaluation was left to stand in an atmosphere of 25 ℃ for 5 minutes, and then the transparent tape was peeled off. The number of peeled grids out of the 25 grids prepared was counted, and the initial adhesion of the polyolefin substrate was evaluated based on the following evaluation criteria.

(evaluation criteria)

O: the number of the peeled grids is 0-4.

And (delta): the number of the stripped grids is 5-14.

X: the number of the peeled grids is 15 or more.

(2) Evaluation of Water resistance

(test method)

The test plate on which the evaluation coating film was formed was immersed in warm water maintained at 40 ℃ for 10 days. After 10 days, the test plate was lifted and dried, and then a grid test was performed by the same method as the grid test for the initial adhesion evaluation, and the number of the peeled grids was calculated, and the water resistance was evaluated based on the following evaluation criteria.

(evaluation criteria)

O: the number of the peeled grids is 0-4.

And (delta): the number of the stripped grids is 5-14.

X: the number of the peeled grids is 15 or more.

(3) Evaluation of Peel Strength (Peel Strength test)

A tape (trade name: cloth tape 102N, manufactured by Nichiban corporation) was adhered to the evaluation coating film of the test sheet on which the evaluation coating film was formed, and the sheet was allowed to stand at 23 ℃ and 65% RH for 1 day. Then, in order to induce peeling of the coating film from the substrate, a 10 mm-wide cut was cut out from the coating film for evaluation from the tape. Subsequently, the peel strength of a film integrally formed from an adhesive tape and a coating film was measured by a tensile tester (trade name: Autograph AGS-100D, manufactured by Shimadzu corporation) at a tensile speed of 50mm/min and converted into the peel strength per 1m, thereby calculating the peel strength.

[ production example 1]

1000 parts of deionized water was charged into a flask equipped with a dropping funnel, a stirrer, a nitrogen gas inlet tube, a thermometer, and a reflux condenser. A pre-emulsion for dropwise addition was prepared by adding 249 parts of deionized water, 120 parts of a 25% aqueous solution (containing 30 parts of a surfactant) of a surfactant (trade name: ADERA REASOAP (registered trademark) SR-10, manufactured by ADEKA, Ltd.), 172 parts of 2-ethylhexyl acrylate (2EHA), 416 parts of Methyl Methacrylate (MMA), and 12 parts of Acrylic Acid (AA) to a dropping funnel. 95 parts of the pre-emulsion was added to the flask and the temperature was raised to 80 ℃ while gently blowing nitrogen. Then, 36 parts of a 5% aqueous solution of ammonium persulfate was added to the flask, and polymerization was started.

Then, the remaining pre-emulsion for dropwise addition took 120 minutes to drop uniformly into the flask. After completion of the dropwise addition, the contents of the flask were kept at 80 ℃ for 60 minutes, and then the pH was adjusted to 9 with a 25% aqueous ammonia solution to terminate the polymerization reaction.

The obtained reaction solution was cooled to room temperature and then filtered through a 300-mesh (JIS standard sieve, the same shall apply hereinafter) wire net to obtain an acrylic resin aqueous dispersion having a solid content of 30 mass%. The acrylic resin particles contained in the obtained acrylic resin aqueous dispersion had an average particle diameter of 130nm and an arithmetic Tg of 30 ℃. The content of the monomer component and the structural unit derived from the surfactant having a polymerizable group in the obtained acrylic resin, the arithmetic Tg and the average particle diameter of the acrylic resin particles, and the pH and the solid content of the acrylic resin aqueous dispersion are shown in table 1.

[ production example 2]

An acrylic resin aqueous dispersion was obtained by performing the same reaction and operation as in production example 1, except that 172 parts of 2-ethylhexyl acrylate (2EHA) was changed to 139 parts, and 416 parts of Methyl Methacrylate (MMA) was changed to 449 parts of cyclohexyl methacrylate (CHMA). The content of the monomer component and the structural unit derived from the surfactant having a polymerizable group in the obtained acrylic resin, the arithmetic Tg and the average particle diameter of the acrylic resin particles, and the pH and the solid content of the acrylic resin aqueous dispersion are shown in table 1.

[ production example 3]

An aqueous acrylic resin dispersion was obtained by performing the same reaction and operation as in production example 1 except that 120 parts of a 25% aqueous solution of a surfactant (trade name: ADARA REASOAP (registered trademark)) SR-10, manufactured by ADEKA, K.K., was changed to 100 parts (including 30 parts of a surfactant) of a 30% aqueous solution of a surfactant having no polymerizable group (trade name: Newcol (registered trademark) 707-SF, manufactured by Nippon emulsifier Co., Ltd.). The content of the monomer component and the structural unit derived from the surfactant having a polymerizable group in the obtained acrylic resin, the arithmetic Tg and the average particle diameter of the acrylic resin particles, and the pH and the solid content of the acrylic resin aqueous dispersion are shown in table 1.

[ production examples 4 to 6]

The same reaction and operation as in production example 1 were carried out except that the amounts of 2-ethylhexyl acrylate (2EHA) and Methyl Methacrylate (MMA) were changed to the amounts shown in table 3, and 2-hydroxyethyl methacrylate (HEMA), 4- (meth) acryloyloxy-1, 2, 2, 6, 6-pentamethylpiperidine (LA-82, manufactured by ADEKA corporation) and γ -methacryloyloxypropyltrimethoxysilane (KBM-503, manufactured by shin-Etsu chemical Co., Ltd.) were used instead of Acrylic Acid (AA) in the amounts shown in table 3, respectively, to obtain an acrylic resin aqueous dispersion. The mass ratio of the components in preparation example 4 is 2 EHA: MMA: HEMA: LA-82: KBM-503: SR-10 (solid component content): 35.9: 61.5: 1.5: 1.0: 0.1: 5. The mass ratio of the components in preparation example 5 is 2 EHA: MMA: HEMA: LA-82: KBM-503: SR-10 (solid component amount) 28.2: 69.2: 1.5: 1.0: 0.1: 5. The mass ratio of the components in preparation example 6 is 2 EHA: MMA: HEMA: LA-82: KBM-503: SR-10 (solid component amount): 21.4: 76.0: 1.5: 1.0: 0.1: 5. The content of the monomer component and the structural unit derived from the surfactant having a polymerizable group in the obtained acrylic resin, the arithmetic Tg and the average particle diameter of the acrylic resin particles, and the pH and the solid content of the acrylic resin aqueous dispersion are shown in table 3.

[ production example 7]

An aqueous acrylic resin dispersion was obtained by carrying out the same reaction and operation as in production example 5, except that the amount of the surfactant (trade name: ADERA REASOAP (registered trade name) SR-10 manufactured by ADEKA, K.K.) used was changed to the amount shown in Table 3. The mass ratio of the components in preparation example 7 is 2 EHA: MMA: HEMA: LA-82: KBM-503: SR-10 (solid component content): 28.2: 69.2: 1.5: 1.0: 0.1: 2. The content of the monomer component and the structural unit derived from the surfactant having a polymerizable group in the obtained acrylic resin, the arithmetic Tg and the average particle diameter of the acrylic resin particles, and the pH and the solid content of the acrylic resin aqueous dispersion are shown in table 3.

[ production examples 8 to 9 ]

The same reaction and operation as in production example 1 were carried out except that 2-ethylhexyl acrylate (2EHA) and Methyl Methacrylate (MMA) were changed to the amounts shown in table 3, to obtain an acrylic resin aqueous dispersion. The mass ratio of the components in preparation example 8 is 2 EHA: MMA: AA: SR-10 (solid component amount): 44.5: 53.5: 2.0: 5. The mass ratio of the components in preparation example 9 is 2 EHA: MMA: AA: SR-10 (solid component amount): 15.5: 82.5: 2.0: 5. The content of the monomer component and the structural unit derived from the surfactant having a polymerizable group in the obtained acrylic resin, the arithmetic Tg and the average particle diameter of the acrylic resin particles, and the pH and the solid content of the acrylic resin aqueous dispersion are shown in table 3.

[ production examples 10 to 11 ]

AN acrylic resin aqueous dispersion was obtained by performing the same reaction and operation as in production example 1, except that 2-ethylhexyl acrylate (2EHA), Methyl Methacrylate (MMA) and Acrylic Acid (AA) were changed to the amounts shown in table 3, and Acrylonitrile (AN) and γ -methacryloxypropyltrimethoxysilane (KBM-503, manufactured by shin-Etsu chemical Co., Ltd.) were used as monomers in the amounts shown in table 3. The mass ratio of the components in preparation example 10 is 2 EHA: MMA: AA: AN: KBM-503: SR-10 (solid component content): 28.5: 68.4: 1.0: 2.0: 0.1: 5. The mass ratio of the components in preparation example 11 is 2 EHA: MMA: AA: AN: KBM-503: SR-10 (solid component amount) 28.5: 67.5: 1.0: 2.0: 1.0: 5. The content of the monomer component and the structural unit derived from the surfactant having a polymerizable group in the obtained acrylic resin, the arithmetic Tg and the average particle diameter of the acrylic resin particles, and the pH and the solid content of the acrylic resin aqueous dispersion are shown in table 3.

[ production examples 12 to 14 ]

An acrylic resin aqueous dispersion was obtained by performing the same reaction and operation as in production example 1, except that 2-ethylhexyl acrylate (2EHA), Methyl Methacrylate (MMA), and Acrylic Acid (AA) were changed to the amounts shown in table 3, and diacetone acrylamide (DAAM, manufactured by mitsubishi chemical corporation) was used as a monomer in the amounts shown in table 3. The mass ratio of the components in preparation example 12 is 2 EHA: MMA: AA: DAAM: SR-10 (solid component content): 28.3: 68.7: 1.0: 2.0: 5. The mass ratio of the components in preparation example 13 was 2 EHA: MMA: AA: DAAM: SR-10 (solid component content): 28.3: 68.7: 1.0: 2.0: 5. The mass ratio of the components in preparation example 14 was 2 EHA: MMA: AA: DAAM: SR-10 (solid component content): 28.3: 68.7: 1.0: 2.0: 5. The content of the monomer component and the structural unit derived from the surfactant having a polymerizable group in the obtained acrylic resin, the arithmetic Tg and the average particle diameter of the acrylic resin particles, and the pH and the solid content of the acrylic resin aqueous dispersion are shown in table 3.

[ production example 15 ]

The same reaction and operation as in production example 1 were carried out except that the amounts of 2-ethylhexyl acrylate (2EHA) and Methyl Methacrylate (MMA) used were changed to the amounts shown in table 4 and Acrylic Acid (AA) was not used, to obtain an acrylic resin aqueous dispersion. The mass ratio of each component in preparation example 15 is 2 EHA: MMA: SR-10 (solid component amount) 28.7: 71.3: 5. The content of the monomer component and the structural unit derived from the surfactant having a polymerizable group in the obtained acrylic resin, the arithmetic Tg and the average particle diameter of the acrylic resin particles, and the pH and the solid content of the acrylic resin aqueous dispersion are shown in table 4.

[ production examples 16 to 17 ]

The same reaction and operation as in production example 1 were carried out except that the amounts of 2-ethylhexyl acrylate (2EHA), Methyl Methacrylate (MMA) and Acrylic Acid (AA) used were changed to the amounts shown in table 4, to obtain an acrylic resin aqueous dispersion. The mass ratio of the components in preparation example 16 is 2 EHA: MMA: AA: SR-10 (solid component content): 28.6: 70.4: 1.0: 5. The mass ratio of the components in preparation example 17 is 2 EHA: MMA: AA: SR-10 (solid component content): 28.5: 68.5: 3.0: 5. The content of the monomer component and the structural unit derived from the surfactant having a polymerizable group in the obtained acrylic resin, the arithmetic Tg and the average particle diameter of the acrylic resin particles, and the pH and the solid content of the acrylic resin aqueous dispersion are shown in table 4.

[ production example 18 ]

The same reaction and operation as in production example 1 were carried out except that the amounts of 2-ethylhexyl acrylate (2EHA), Methyl Methacrylate (MMA) and Acrylic Acid (AA) used were changed to the amounts shown in table 4, and 2-hydroxyethyl methacrylate (HEMA) was used as a monomer in the amounts shown in table 4, to obtain an acrylic resin aqueous dispersion. The preparation method 18 comprises the following components at a mass ratio of 2 EHA: MMA: AA: HEMA: SR-10 (solid component content) of 28.3: 68.7: 1.0: 2.0: 5. The content of the monomer component and the structural unit derived from the surfactant having a polymerizable group in the obtained acrylic resin, the arithmetic Tg and the average particle diameter of the acrylic resin particles, and the pH and the solid content of the acrylic resin aqueous dispersion are shown in table 4.

[ production example 19 ]

The same reaction and operation as in production example 1 were carried out except that the amounts of 2-ethylhexyl acrylate (2EHA), Methyl Methacrylate (MMA) and Acrylic Acid (AA) used were changed to the amounts shown in table 4, and methoxyethyl acrylate (MEA) was used as a monomer in the amount shown in table 4, to obtain an acrylic resin aqueous dispersion. The mass ratio of the components in preparation example 19 is 2 EHA: MMA: AA: MEA: SR-10 (solid component amount) 27.0: 70.0: 1.0: 2.0: 5. The content of the monomer component and the structural unit derived from the surfactant having a polymerizable group in the obtained acrylic resin, the arithmetic Tg and the average particle diameter of the acrylic resin particles, and the pH and the solid content of the acrylic resin aqueous dispersion are shown in table 4.

[ production example 20 ]

The same reaction and operation as in production example 1 were carried out except that the amounts of 2-ethylhexyl acrylate (2EHA), Methyl Methacrylate (MMA) and Acrylic Acid (AA) used were changed to the amounts shown in table 4, and Acrylonitrile (AN) was used as a monomer in the amounts shown in table 4, to obtain AN acrylic resin aqueous dispersion. The preparation example 20 has a mass ratio of components of 2 EHA: MMA: AA: AN: SR-10 (solid component content) of 28.5: 68.5: 1.0: 2.0: 5. The content of the monomer component and the structural unit derived from the surfactant having a polymerizable group in the obtained acrylic resin, the arithmetic Tg and the average particle diameter of the acrylic resin particles, and the pH and the solid content of the acrylic resin aqueous dispersion are shown in table 4.

[ production example 21 ]

The same reaction and operation as in production example 1 were carried out except that the amounts of 2-ethylhexyl acrylate (2EHA), Methyl Methacrylate (MMA) and Acrylic Acid (AA) used were changed to the amounts shown in table 4, and acrylamide (AAm) was used as a monomer in the amount shown in table 4, to obtain an acrylic resin aqueous dispersion. The mass ratio of the components in preparation example 21 is 2 EHA: MMA: AA: AAm: SR-10 (solid component content): 28.9: 68.1: 1.0: 2.0: 5. The content of the monomer component and the structural unit derived from the surfactant having a polymerizable group in the obtained acrylic resin, the arithmetic Tg and the average particle diameter of the acrylic resin particles, and the pH and the solid content of the acrylic resin aqueous dispersion are shown in table 4.

[ production example 22 ]

An acrylic resin aqueous dispersion was obtained by performing the same reaction and operation as in production example 1, except that the amounts of 2-ethylhexyl acrylate (2EHA), Methyl Methacrylate (MMA), and Acrylic Acid (AA) used were changed to the amounts shown in table 4, and diacetone acrylamide (DAAM, manufactured by mitsubishi chemical corporation) was used as a monomer in the amounts shown in table 4. The preparation example 22 has a mass ratio of components of 2 EHA: MMA: AA: DAAM: SR-10 (solid component content) of 28.3: 68.7: 1.0: 2.0: 5. The content of the monomer component and the structural unit derived from the surfactant having a polymerizable group in the obtained acrylic resin, the arithmetic Tg and the average particle diameter of the acrylic resin particles, and the pH and the solid content of the acrylic resin aqueous dispersion are shown in table 4.

[ production example 23 ]

The same reaction and operation as in production example 1 were carried out except that the amounts of 2-ethylhexyl acrylate (2EHA) and Methyl Methacrylate (MMA) used were changed to the amounts shown in table 4, Acrylic Acid (AA) was not used, and acrylamide (AAm) was used as a monomer in an amount shown in table 4, to obtain an acrylic resin aqueous dispersion. The mass ratio of the components in preparation example 23 is 2 EHA: MMA: AAm: SR-10 (solid component amount): 29.0: 69.0: 2.0: 5. The content of the monomer component and the structural unit derived from the surfactant having a polymerizable group in the obtained acrylic resin, the arithmetic Tg and the average particle diameter of the acrylic resin particles, and the pH and the solid content of the acrylic resin aqueous dispersion are shown in table 4.

[ production example 24 ]

The same reaction and operation as in production example 1 were carried out except that the used amounts of 2-ethylhexyl acrylate (2EHA), Methyl Methacrylate (MMA) and Acrylic Acid (AA) were changed to the amounts shown in table 4, and 2-hydroxyethyl methacrylate (HEMA) was used as a monomer in an amount shown in table 4, and Aqualon (registered trademark) AR-10 (manufactured by first industrial pharmaceutical company) in an amount shown in table 4 was used as a surfactant instead of ADERA soap (registered trademark) SR-10, to obtain an acrylic resin aqueous dispersion. The mass ratio of the components in preparation example 24 is 2 EHA: MMA: AA: HEMA: AR-10 (solid component content): 28.3: 68.8: 1.0: 2.0: 5. The content of the monomer component and the structural unit derived from the surfactant having a polymerizable group in the obtained acrylic resin, the arithmetic Tg and the average particle diameter of the acrylic resin particles, and the pH and the solid content of the acrylic resin aqueous dispersion are shown in table 4.

[ production example 25 ]

1097 parts of deionized water were charged into a flask equipped with a dropping funnel, a stirrer, a nitrogen gas inlet tube, a thermometer, and a reflux condenser. To a dropping funnel, 110 parts of deionized water, 60 parts of a 25% aqueous solution of a surfactant (trade name: ADERA soap (registered trademark) SR-10, manufactured by ADEKA corporation) (containing 15 parts of a surfactant), 99 parts of 2-ethylhexyl acrylate (2EHA), 186 parts of Methyl Methacrylate (MMA), 12 parts of Acrylic Acid (AA), and 3 parts of 2-hydroxyethyl methacrylate (HEMA) were added, thereby preparing a pre-emulsion for dropwise addition. 50 parts of the pre-emulsion were added to the flask and the temperature of the contents of the flask was raised to 80 ℃ while gently blowing nitrogen. Then, 36 parts of a 5% aqueous solution of ammonium persulfate was added to the flask, and polymerization was started.

Then, the remaining pre-emulsion for dropwise addition took 120 minutes to drop uniformly into the flask. The content of the flask was kept at 80 ℃ for 60 minutes, and then 11.3 parts of 25% aqueous ammonia solution (an amount to neutralize AA by 100%) was added. After the addition, the contents of the flask were held at 80 ℃ for 60 minutes.

Then, a 2 nd-stage pre-emulsion comprising 110 parts of deionized water, 60 parts of a 25% aqueous solution of a surfactant (product name: ADERA REASOAP (registered trademark) SR-10, manufactured by ADEKA, Inc.), 15 parts of the surfactant, 101 parts of 2-ethylhexyl acrylate, 186 parts of methyl methacrylate, 6 parts of 2-hydroxyethyl methacrylate, 0.6 part of a silyl group-containing monomer (product name: KBM-503, manufactured by shin-Etsu chemical Co., Ltd.), and 6 parts of 2, 2, 6, 6-tetramethyl-4-piperidyl methacrylate (ADK STABLA-87) was uniformly dropped into the flask for 120 minutes. After the addition was complete, the contents of the flask were held at 80 ℃ for 120 minutes. The contents of the flask were then adjusted to pH 9 with 25% aqueous ammonia solution to terminate the polymerization reaction.

The obtained reaction solution was cooled to room temperature and then filtered through a 300-mesh (JIS standard sieve, the same shall apply hereinafter) wire net to obtain an acrylic resin aqueous dispersion having a solid content of 30 mass%. The acrylic resin particles contained in the obtained acrylic resin aqueous dispersion had an average particle diameter of 100nm and an arithmetic Tg of 19 ℃. The content of the monomer component and the structural unit derived from the surfactant having a polymerizable group in the obtained acrylic resin, the arithmetic Tg and the average particle diameter of the acrylic resin particles, and the pH and the solid content of the acrylic resin aqueous dispersion are shown in table 7.

[ production example 26 ]

AN aqueous acrylic resin dispersion having a solid content of 30 mass% was obtained in the same manner as in production example 25 except that a pre-emulsion composed of 110 parts of deionized water, 60 parts of a 25% aqueous solution (containing 15 parts of a surfactant) (manufactured by ADEKA reafa, registered trademark) SR-10, 2-ethylhexyl acrylate 101 parts, 180 parts of methyl methacrylate, 6 parts of 2-hydroxyethyl methacrylate, 0.6 part of a silyl group-containing monomer (manufactured by shin-Etsu chemical Co., Ltd., trademark: KBM-503), and 12 parts of Acrylonitrile (AN) was used as the pre-emulsion in stage 2. The acrylic resin particles contained in the obtained acrylic resin aqueous dispersion had an average particle diameter of 100nm and an arithmetic Tg of 19 ℃. The content of the monomer component and the structural unit derived from the surfactant having a polymerizable group in the obtained acrylic resin, the arithmetic Tg and the average particle diameter of the acrylic resin particles, and the pH and the solid content of the acrylic resin aqueous dispersion are shown in table 7.

[ production example 27 ]

The same reaction and operation as in production example 18 were carried out except that the amounts of 2-ethylhexyl acrylate (2EHA) and Methyl Methacrylate (MMA) used were changed to the amounts shown in table 7, and styrene (St) (5 mass% based on the total amount of monomers) in the amounts shown in table 7 was used as monomers, to obtain an acrylic resin aqueous dispersion. The acrylic resin particles contained in the obtained acrylic resin aqueous dispersion had an average particle diameter of 110nm and an arithmetic Tg of 30 ℃. The content of the monomer component and the structural unit derived from the surfactant having a polymerizable group in the obtained acrylic resin, the arithmetic Tg and the average particle diameter of the acrylic resin particles, and the pH and the solid content of the acrylic resin aqueous dispersion are shown in table 7.

[ production example 28 ]

The same reaction and operation as in production example 18 were carried out except that 2-ethylhexyl acrylate (2EHA) and Methyl Methacrylate (MMA) were changed to the amounts shown in table 7, and styrene (St) was used as a monomer in the amount shown in table 7 (60 mass% based on the total amount of the monomer), to obtain an acrylic resin aqueous dispersion. The acrylic resin particles contained in the obtained acrylic resin aqueous dispersion had an average particle diameter of 100nm and an arithmetic Tg of 30 ℃. The content of the monomer component and the structural unit derived from the surfactant having a polymerizable group in the obtained acrylic resin, the arithmetic Tg and the average particle diameter of the acrylic resin particles, and the pH and the solid content of the acrylic resin aqueous dispersion are shown in table 7.

[ example 1]

50 parts (including 15 parts of solid content) of the acrylic resin aqueous dispersion obtained in production example 1 and 50 parts (including 15 parts of solid content) of a polyolefin aqueous dispersion (trade name: Hardlen (registered trademark) NZ-1004, manufactured by Toyobo Co., Ltd., modified polyolefin aqueous dispersion obtained by modifying 100 parts of polypropylene with 2.0 parts of maleic anhydride which is an unsaturated carboxylic acid, and 30% by mass of solid content) of an nonchlorinated polyolefin having a carboxyl group and an aqueous medium were mixed, and the mixture was stirred with a homomixer at 500 rpm for 30 minutes. As a result, an aqueous resin composition containing an acrylic resin aqueous dispersion containing a structural unit derived from a surfactant having a polymerizable group and a non-chlorinated polyolefin aqueous dispersion having a carboxyl group was obtained. The evaluation results of the obtained aqueous resin composition are shown in table 2.

[ example 2]

An aqueous resin composition was obtained in the same manner as in example 1, except that the aqueous acrylic resin dispersion obtained in production example 1 was changed to the aqueous acrylic resin dispersion obtained in production example 2. The evaluation results of the obtained aqueous resin composition are shown in table 2.

[ example 3]

To 100 parts of the solid content (total mass of the non-chlorinated polyolefin having a carboxyl group and the acrylic resin) in the aqueous resin composition obtained in example 1, 2 parts of a crosslinking agent (trade name: eporos (registered trademark) WS-500, manufactured by japan catalyst, ltd., 0.8 part of a water-soluble polymer containing an oxazoline group) was mixed, and the mixture was stirred for 30 minutes at a rotation speed of 500 times/minute using a homomixer. As a result, an aqueous resin composition containing a crosslinking agent capable of reacting with a carboxyl group was obtained. The evaluation results of the obtained aqueous resin composition are shown in table 2.

[ example 4]

To 100 parts of the solid content (total mass of the non-chlorinated polyolefin having a carboxyl group and the acrylic resin) in the aqueous resin composition obtained in example 2, 2 parts of a crosslinking agent (trade name: Epocros (registered trademark) WS-500, manufactured by Nippon catalyst Co., Ltd., 0.8 part of a water-soluble polymer containing an oxazoline group) was mixed, and the mixture was stirred for 30 minutes at a rotation speed of 500 cycles/minute using a homomixer. As a result, an aqueous resin composition containing a crosslinking agent capable of reacting with a carboxyl group was obtained. The evaluation results of the obtained aqueous resin composition are shown in table 2.

[ comparative example 1]

As the aqueous resin composition, only the above-mentioned polyolefin aqueous dispersion (trade name: Hardlen (registered trade name) NZ-1004, manufactured by Toyobo Co., Ltd., which is a modified polyolefin aqueous dispersion obtained by modifying 100 parts of polypropylene with 2.0 parts of an unsaturated carboxylic acid) was used. The evaluation results of the aqueous resin composition are shown in table 2.

[ comparative example 2]

As the aqueous resin composition, only the acrylic resin aqueous dispersion obtained in production example 1 was used. The evaluation results of the aqueous resin composition are shown in table 2.

[ comparative example 3]

As the aqueous resin composition, only the acrylic resin aqueous dispersion obtained in production example 2 was used. The evaluation results of the aqueous resin composition are shown in table 2.

[ comparative example 4]

An aqueous resin composition was obtained by performing the same operations as in example 1, except that the aqueous acrylic resin dispersion obtained in production example 3 was used instead of the aqueous acrylic resin dispersion obtained in production example 1. The evaluation results of the obtained aqueous resin composition are shown in table 2.

[ examples 5 to 12, 16 to 24 ]

Aqueous resin compositions were obtained in the same manner as in example 1, except that the acrylic resin aqueous dispersions obtained in production example 1 were changed to the acrylic resin aqueous dispersions obtained in production examples shown in tables 5 and 6, respectively. The evaluation results of the obtained aqueous resin compositions are shown in tables 5 and 6.

[ example 13 ]

An aqueous resin composition was obtained in the same manner as in example 1, except that the aqueous acrylic resin dispersion obtained in production example 1 was changed to the aqueous acrylic resin dispersion obtained in production example 12.

To the obtained aqueous resin composition, adipic acid dihydrazide (manufactured by mitsubishi chemical corporation) equivalent to 0.5 equivalent of diacetone acrylamide (DAAM, manufactured by mitsubishi chemical corporation) used in production example 12 was mixed as a crosslinking agent, and the mixture was stirred for 30 minutes at 500 cycles/minute using a homomixer. As a result, an aqueous resin composition containing a crosslinking agent capable of reacting with a carbonyl group was obtained. The evaluation results of the obtained aqueous resin composition are shown in table 5.

[ example 14 ]

An aqueous resin composition containing a crosslinking agent reactive with a carbonyl group was obtained in the same manner as in example 13 except that the aqueous acrylic resin dispersion obtained in production example 1 was changed to the aqueous acrylic resin dispersion obtained in production example 13 and the amount of adipic acid dihydrazide (manufactured by mitsubishi chemical corporation) was changed to 1 equivalent of diacetone acrylamide (DAAM, manufactured by mitsubishi chemical corporation) used in production example 13. The evaluation results of the obtained aqueous resin composition are shown in table 5.

[ example 15 ]

An aqueous resin composition containing a crosslinking agent reactive with a carbonyl group was obtained in the same manner as in example 13, except that the aqueous acrylic resin dispersion obtained in production example 1 was changed to the aqueous acrylic resin dispersion obtained in production example 14, and the amount of adipic acid dihydrazide (manufactured by mitsubishi chemical corporation) was changed to 1.5 equivalents of diacetone acrylamide (DAAM, manufactured by mitsubishi chemical corporation) used in production example 14. The evaluation results of the obtained aqueous resin composition are shown in table 5.

[ example 25 ]

An aqueous resin composition was obtained in the same manner as in example 1 except that the aqueous acrylic resin dispersion obtained in production example 1 was changed to the aqueous acrylic resin dispersion obtained in production example 22, and the aqueous polyolefin dispersion containing the non-chlorinated polyolefin having a carboxyl group and the aqueous medium was changed to 50 parts (including 15 parts of the solid content) of Hardlen (registered trademark) NZ-1015 (a modified polyolefin aqueous dispersion obtained by modifying 100 parts of polypropylene with 1.1 parts of an unsaturated carboxylic acid, and the solid content: 30 mass%) manufactured by tokyo corporation. The evaluation results of the obtained aqueous resin composition are shown in table 6.

[ example 26 ]

An aqueous resin composition was obtained in the same manner as in example 1, except that the aqueous acrylic resin dispersion obtained in production example 1 was changed to the aqueous acrylic resin dispersion obtained in production example 24. The evaluation results of the obtained aqueous resin composition are shown in table 6.

[ example 27 ]

An aqueous resin composition was obtained in the same manner as in example 1 except that 40 parts (including 12 parts of solid content) of the acrylic resin aqueous dispersion obtained in production example 18 and 60 parts (including 18 parts of solid content) of a polyolefin aqueous dispersion (trade name: Hardlen (registered trademark) NZ-1004, manufactured by Toyobo Co., Ltd., amount of solid content: 30% by mass) containing a non-chlorinated polyolefin having a carboxyl group and an aqueous medium were mixed. The evaluation results of the obtained aqueous resin composition are shown in table 8.

[ example 28 ]

An aqueous resin composition was obtained in the same manner as in example 1 except that 60 parts (including 18 parts of solid content) of the acrylic resin aqueous dispersion obtained in production example 18 and 40 parts (including 12 parts of solid content) of a polyolefin aqueous dispersion (trade name: Hardlen (registered trademark) NZ-1004, manufactured by Toyobo Co., Ltd., amount of solid content: 30% by mass) containing a non-chlorinated polyolefin having a carboxyl group and an aqueous medium were mixed. The evaluation results of the obtained aqueous resin composition are shown in table 8.

[ example 29 ]

An aqueous resin composition was obtained in the same manner as in example 1, except that the aqueous acrylic resin dispersion obtained in production example 1 was changed to the aqueous acrylic resin dispersion obtained in production example 25. The evaluation results of the obtained aqueous resin composition are shown in table 8.

[ example 30 ]

An aqueous resin composition was obtained in the same manner as in example 1, except that the aqueous acrylic resin dispersion obtained in production example 1 was changed to the aqueous acrylic resin dispersion obtained in production example 26. The evaluation results of the obtained aqueous resin composition are shown in table 8.

[ example 31 ]

An aqueous resin composition was obtained in the same manner as in example 1, except that the aqueous acrylic resin dispersion obtained in production example 1 was changed to the aqueous acrylic resin dispersion obtained in production example 27. The evaluation results of the obtained aqueous resin composition are shown in table 8.

[ example 32 ]

An aqueous resin composition was obtained in the same manner as in example 1, except that the aqueous acrylic resin dispersion obtained in production example 1 was changed to the aqueous acrylic resin dispersion obtained in production example 28. The evaluation results of the obtained aqueous resin composition are shown in table 8.

[ example 33 ]

An aqueous resin composition was obtained in the same manner as in examples 23 and 25 except that the aqueous polyolefin dispersion containing the non-chlorinated polyolefin having a carboxyl group and the aqueous medium was changed to 50 parts (including 15 parts of the solid content) of Hardlen (registered trademark) NA-6600 (which is an aqueous modified polyolefin dispersion obtained by modifying 100 parts of polypropylene with 1.1 part of an unsaturated carboxylic acid, and the solid content: 30 mass%) manufactured by tokyo corporation. The evaluation results of the obtained aqueous resin composition are shown in table 8.

[ comparative example 5]

In addition to comparative example 1, only Hardlen (registered trademark) NZ-1015 (a modified polyolefin aqueous dispersion obtained by modifying 100 parts of polypropylene with 1.1 parts of unsaturated carboxylic acid) was used as the aqueous resin composition in place of Hardlen (registered trademark) NZ-1004 (a modified polyolefin aqueous dispersion obtained by modifying 100 parts of polypropylene with 2.0 parts of unsaturated carboxylic acid). The evaluation results of the aqueous resin composition are shown in Table 8.

[ comparative example 6]

In addition to comparative example 1, only Hardlen (registered trademark) NA-6600 (which is a modified polyolefin aqueous dispersion obtained by modifying 100 parts of polypropylene with 1.1 parts of unsaturated carboxylic acid) was used as the aqueous resin composition in place of Hardlen (registered trademark) NZ-1004 (which is a modified polyolefin aqueous dispersion obtained by modifying 100 parts of polypropylene with 2.0 parts of unsaturated carboxylic acid). The evaluation results of the aqueous resin composition are shown in Table 8.

[ Table 1]

[ Table 2]

[ Table 3]

[ Table 4]

[ Table 5]

[ Table 6]

[ Table 7]

[ Table 8]

From examples 1 to 4, it is understood that the aqueous resin composition obtained by mixing the aqueous olefin dispersion and the aqueous acrylic resin dispersion is excellent in initial adhesion and water resistance.

Furthermore, it is understood from examples 5 to 33 that the aqueous resin compositions obtained by mixing the aqueous olefin dispersion and the aqueous acrylic resin dispersion are excellent in initial adhesion and water resistance.

On the other hand, it is clear from comparative examples 1, 5 and 6 that the aqueous resin compositions prepared using only the olefin aqueous dispersion are inferior in initial adhesion and water resistance. In addition, it is seen from comparative example 4 that the aqueous resin composition obtained by mixing the above-mentioned olefin aqueous dispersion and an aqueous dispersion containing an acrylic resin obtained by using a surfactant having no polymerizable group is inferior in initial adhesion and water resistance.

(availability in industry)

The present invention is useful as a water-based primer for polyolefin molded articles, for example, parts such as vehicle bumpers and vehicle moldings, and parts for household electric appliances.

Claims

1. An aqueous resin composition comprising:

a non-chlorinated polyolefin having a carboxyl group;

an acrylic resin containing a structural unit derived from a surfactant having a polymerizable group; and

an aqueous medium.

2. The aqueous resin composition according to claim 1,

the content of the structural unit derived from the surfactant having a polymerizable group is 1 to 10% by mass relative to the total amount of the structural units derived from the monomers constituting the acrylic resin.

3. The aqueous resin composition according to claim 1 or 2,

the aqueous resin composition contains 0 to 5 mass% of a surfactant having no polymerizable group relative to the acrylic resin.

4. The aqueous resin composition according to any one of claims 1 to 3,

the acrylic resin further contains a structural unit derived from an unsaturated carboxylic acid.

5. The aqueous resin composition according to any one of claims 1 to 4,

the aqueous resin composition contains a crosslinking agent capable of reacting with a carboxyl group.

6. A water-based primer composition which is excellent in water-based adhesion,

comprising the aqueous resin composition according to any one of claims 1 to 5, and is suitable for polyolefin substrates.

7. A molded article comprising a molded article of a thermoplastic resin,

comprising the waterborne base coat composition of claim 6.

8. A process for producing an aqueous resin composition,

which comprises a step of mixing a polyolefin aqueous dispersion (A) and an acrylic resin aqueous dispersion (B),

wherein the polyolefin aqueous dispersion (A) comprises an aqueous medium and a non-chlorinated polyolefin having a carboxyl group, and the acrylic resin aqueous dispersion (B) is obtained by emulsion polymerization of a monomer in the presence of a surfactant having a polymerizable group.