阅读说明：本技术 水性树脂组合物 (Aqueous resin composition ) 是由 宫崎惠太朗 柏原健二 于 2020-03-26 设计创作，主要内容包括：本发明提供即使在80℃烘烤中对聚烯烃基材也显示高剥离强度,含有丙烯酸成分并无损密合力的聚烯烃与丙烯酸混合型涂料、油墨、粘接剂、密封剂或底漆用水性树脂组合物。一种水性树脂组合物,是含有酸改性聚烯烃树脂(A)及(甲基)丙烯酸酯共聚物(B)的水性树脂组合物,酸改性聚烯烃树脂(A)以0.5～10质量％的范围含有不饱和羧酸或其酸酐,(甲基)丙烯酸酯共聚物(B)含有酯部分是碳原子数为12以上的烃基的(甲基)丙烯酸酯(B1)及酯部分是碳原子数为11以下的烃基的(甲基)丙烯酸酯(B2)作为共聚成分。(The invention provides an aqueous resin composition for polyolefin and acrylic hybrid coating, ink, adhesive, sealant or primer, which exhibits high peel strength to polyolefin substrates even when baked at 80 ℃ and contains an acrylic component without impairing adhesion. An aqueous resin composition comprising an acid-modified polyolefin resin (A) and a (meth) acrylate copolymer (B), wherein the acid-modified polyolefin resin (A) contains an unsaturated carboxylic acid or an anhydride thereof in an amount of 0.5 to 10% by mass, and the (meth) acrylate copolymer (B) contains, as copolymerization components, a (meth) acrylate (B1) having an ester moiety of a hydrocarbon group having 12 or more carbon atoms and a (meth) acrylate (B2) having an ester moiety of a hydrocarbon group having 11 or less carbon atoms.)

1. An aqueous resin composition comprising an acid-modified polyolefin resin (A) and a (meth) acrylate copolymer (B),

the acid-modified polyolefin resin (A) contains an unsaturated carboxylic acid or an anhydride thereof in an amount of 0.5 to 10% by mass,

the (meth) acrylate copolymer (B) contains, as copolymerization components, a (meth) acrylate (B1) in which the ester moiety is a hydrocarbon group having 12 or more carbon atoms and a (meth) acrylate (B2) in which the ester moiety is a hydrocarbon group having 11 or less carbon atoms.

2. The aqueous resin composition according to claim 1, wherein the (meth) acrylate copolymer (B) further contains a polar group-containing monomer (B3), and the polar group-containing monomer (B3) is at least 1 selected from the group consisting of a polar group-containing (meth) acrylate, (meth) acrylic acid and (meth) acrylamide.

3. The aqueous resin composition according to claim 1 or 2, which contains either or both of a surfactant and a basic compound.

4. The aqueous resin composition according to any one of claims 1 to 3, wherein the content of the (meth) acrylic acid ester copolymer (B) is 40 to 250 parts by mass based on 100 parts by mass of the acid-modified polyolefin resin (A).

5. The aqueous resin composition according to any one of claims 1 to 4, wherein the mass ratio of the (meth) acrylate (B1) having an ester moiety of a hydrocarbon group having 12 or more carbon atoms to the (meth) acrylate (B2) having an ester moiety of a hydrocarbon group having 11 or less carbon atoms contained in the (meth) acrylate copolymer (B) is 70/30 to 20/80.

6. The aqueous resin composition according to any one of claims 1 to 5, wherein the glass transition temperature Tg of the (meth) acrylate copolymer (B) is in the range of-40 ℃ to 80 ℃.

7. The aqueous resin composition according to any one of claims 1 to 6, wherein the acid-modified polyolefin resin (A) has a melting point of 90 ℃ or lower as determined by Differential Scanning Calorimetry (DSC).

8. A coating material for polyolefin substrates, comprising the aqueous resin composition according to any one of claims 1 to 7.

9. An ink for polyolefin substrates, comprising the aqueous resin composition according to any one of claims 1 to 7.

10. An adhesive for polyolefin substrates, comprising the aqueous resin composition according to any one of claims 1 to 7.

11. A sealant for polyolefin substrates, comprising the aqueous resin composition according to any one of claims 1 to 7.

12. A primer for coating a polyolefin substrate, comprising the aqueous resin composition according to any one of claims 1 to 7.

Technical Field

The present invention relates to an aqueous resin composition having high adhesion to polyolefin substrates.

Background

Generally, polyolefin resins such as polypropylene, polyethylene, ethylene-propylene copolymers, ethylene-propylene-diene copolymers, and poly-4-methyl-1-pentene are relatively inexpensive and have excellent chemical resistance, water resistance, heat resistance, and the like, and are widely used in various fields as materials for automobile parts, electric parts, building materials, packaging films, and the like. However, since the polyolefin resin is crystalline and nonpolar, it is difficult to apply and bond the polyolefin resin.

For coating and bonding of such a polyolefin resin which is difficult to adhere to a substrate, a chlorinated polyolefin having a strong adhesion to a polyolefin resin is generally used as a conventional binder resin (see patent documents 1 and 2). In addition, in order to compensate for the disadvantage that the chlorinated polyolefin has poor adhesion to a substrate or the limitation of the adhesion target, the chlorinated polyolefin is mixed with an acrylic resin, a polyurethane resin or a polyester resin, or these resins and the chlorinated polyolefin are graft-polymerized to form an adhesive composition, followed by coating and adhesion (see patent documents 3 and 4).

However, these adhesive compositions are often used in a form dissolved in an organic solvent such as toluene or xylene, and a large amount of the organic solvent is released into the atmosphere at the time of application, and therefore, they are not preferable in terms of environment, hygiene, and the like.

Therefore, aqueous resin compositions containing polyolefin resins that do not contain organic solvents have been proposed (see patent documents 5 and 6). However, in these compositions, the polyolefin resin itself is a substance having low polarity, and when it is used in a mixture with an acrylic resin, a polyurethane resin, an epoxy resin or a polyester resin, it is difficult to be compatible with each other, and there is a problem that the desired physical properties cannot be expressed.

In order to solve such problems, there has been proposed a method for producing an emulsion in which a polyolefin is dissolved in an acrylic monomer, the monomer is polymerized after phase inversion emulsification (see patent documents 7 and 8). In these production methods, the cost can be suppressed by shortening the solvent removal step, and since acrylic acid is contained, an aqueous resin composition having excellent compatibility with other resins can be obtained.

Documents of the prior art

Patent document

Patent document 1: japanese laid-open patent publication No. Sho 59-75958

Patent document 2: japanese laid-open patent publication No. 60-99138

Patent document 3: japanese patent laid-open publication No. 6-16746

Patent document 4: japanese laid-open patent publication No. 8-12913

Patent document 5: japanese laid-open patent publication No. 6-256592

Patent document 6: japanese patent laid-open publication No. 2004-107539

Patent document 7: japanese laid-open patent publication No. 6-80738

Patent document 8: japanese patent laid-open publication No. 2010-001334

Disclosure of Invention

Technical problem to be solved by the invention

On the other hand, since half of the resin component in these compositions is acrylic acid, there is a problem that the peel strength with the polyolefin substrate is reduced.

The present invention has been made to solve the above problems, and an object of the present invention is to provide an aqueous resin composition for polyolefin and acrylic hybrid coating, ink, adhesive, sealant or primer, which exhibits high peel strength even when baked at 80 ℃ to a polyolefin substrate and does not impair adhesion even when containing an acrylic component.

Means for solving the problems

The present inventors have found that the above problems can be solved by an aqueous resin composition containing an acid-modified polyolefin resin (a) and a (meth) acrylate copolymer (B) containing a (meth) acrylate (B1) in which the ester moiety is a hydrocarbon group having 12 or more carbon atoms and a (meth) acrylate (B2) in which the ester moiety is a hydrocarbon group having 11 or less carbon atoms.

The present invention is as follows.

An aqueous resin composition comprising an acid-modified polyolefin resin (A) and a (meth) acrylate copolymer (B),

the acid-modified polyolefin resin (A) contains an unsaturated carboxylic acid or an anhydride thereof in an amount of 0.5 to 10% by mass,

the (meth) acrylate copolymer (B) contains a (meth) acrylate (B1) in which the ester moiety is a hydrocarbon group having 12 or more carbon atoms and a (meth) acrylate (B2) in which the ester moiety is a hydrocarbon group having 11 or less carbon atoms.

The (meth) acrylate copolymer (B) preferably further contains a polar group-containing monomer (B3), and the polar group-containing monomer (B3) is at least 1 selected from the group consisting of a polar group-containing (meth) acrylate, (meth) acrylic acid, and (meth) acrylamide.

It is preferable that either one or both of a surfactant and a basic compound be contained in addition to the acid-modified polyolefin resin (a) and the (meth) acrylate copolymer (B), and the content of the (meth) acrylate copolymer (B) is preferably in the range of 40 to 250 parts by mass with respect to 100 parts by mass of the acid-modified polyolefin resin (a).

The mass ratio of the (meth) acrylate (B1) in which the ester moiety is a hydrocarbon group having 12 or more carbon atoms to the (meth) acrylate (B2) in which the ester moiety is a hydrocarbon group having 11 or less carbon atoms contained in the (meth) acrylate copolymer (B) is preferably in the range of 70/30 to 20/80.

The glass transition temperature (Tg) of the (meth) acrylate copolymer (B) is preferably in the range of-40 to 80 ℃ and the melting point of the acid-modified polyolefin resin (A) as determined by Differential Scanning Calorimetry (DSC) is preferably 90 ℃ or lower.

The aqueous resin composition as described in any of the above may be used for a coating material for polyolefin films, sheets or molded bodies, ink, adhesive, sealant or primer.

ADVANTAGEOUS EFFECTS OF INVENTION

The aqueous resin composition of the present invention exhibits excellent adhesion to polyolefin-based substrates and water resistance even when baked at 80 ℃, and can exhibit high peel strength equivalent to that of an acid-modified polyolefin resin alone, despite containing an acrylic resin. Further, it is possible to provide an aqueous resin composition for paints, inks, adhesives, sealants or primers which is excellent in compatibility with various polar resins, does not contain an organic solvent, and can be obtained by shortening the production process of the solvent removal step.

Detailed Description

The present invention will be described in detail below.

The present invention is an aqueous resin composition containing an acid-modified polyolefin resin (A) and a (meth) acrylate copolymer (B), wherein the acid-modified polyolefin resin (A) contains an unsaturated carboxylic acid or an anhydride thereof in an amount of 0.5 to 10% by mass, and the (meth) acrylate copolymer (B) contains a (meth) acrylate (B1) in which an ester moiety is a hydrocarbon group having 12 or more carbon atoms and a (meth) acrylate (B2) in which an ester moiety is a hydrocarbon group having 11 or less carbon atoms.

< acid-modified polyolefin resin (A) >

The acid-modified polyolefin resin (a) used in the present invention is obtained by, for example, graft-copolymerizing at least 1 kind selected from α, β -unsaturated carboxylic acids and anhydrides thereof onto at least 1 kind selected from polypropylene, propylene- α -olefin copolymer, polyethylene, ethylene- α -olefin copolymer, poly-1-butene and 1-butene- α -olefin copolymer.

Here, the propylene- α -olefin copolymer refers to a copolymer obtained by copolymerizing α -olefin with propylene as a main component. Examples of the α -olefin include α -olefins having 2 or 4 to 20 carbon atoms such as ethylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-decene, 1-dodecene, 1-hexadecene, and 4-methyl-1-pentene. The content of the propylene component in the propylene- α -olefin copolymer is preferably 50 mol% or more, and more preferably 70 mol% or more. When the content of the propylene component is 50 mol% or more, the adhesiveness to the polypropylene base material is good.

The ethylene- α -olefin copolymer is a copolymer obtained by copolymerizing α -olefin with ethylene as a main component. Examples of the α -olefin include α -olefins having 3 to 20 carbon atoms such as propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-decene, 1-dodecene, 1-hexadecene, and 4-methyl-1-pentene. The ethylene content in the ethylene- α -olefin copolymer is preferably 75 mol% or more. When the ethylene component content is 75 mol% or more, the adhesion to the polyethylene substrate is good.

The 1-butene- α -olefin copolymer is a copolymer obtained by copolymerizing 1-butene mainly with α -olefin. Examples of the α -olefin include α -olefins having 2 to 3 or 5 to 20 carbon atoms such as ethylene, propylene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-decene, 1-dodecene, 1-hexadecene, and 4-methyl-1-pentene. The content of the 1-butene component in the 1-butene- α -olefin copolymer is preferably 65 mol% or more. When the content of the 1-butene component is 65 mol% or more, the adhesiveness to a polypropylene base material or a poly-1-butene base material is good.

Examples of the α, β -unsaturated carboxylic acid or anhydride thereof graft-copolymerized with the polyolefin include maleic acid, maleic anhydride, fumaric acid, citraconic anhydride, mesaconic acid, itaconic anhydride, aconitic acid, aconitic anhydride, nadic anhydride, and the like. Among them, maleic anhydride and itaconic anhydride are preferable.

The content of the alpha, beta-unsaturated carboxylic acid component or the acid anhydride component thereof in the acid-modified polyolefin resin (A) is 0.5 to 10 mass%. Preferably 0.7% by mass or more, and more preferably 1% by mass or more. Further, it is preferably 5% by mass or less, and more preferably 3% by mass or less. When the content of the α, β -unsaturated carboxylic acid component or the acid anhydride component thereof is within this range, the phase inversion emulsification is facilitated, and the water resistance of the coating film obtained from the aqueous resin composition is good.

As a method for graft-copolymerizing at least 1 kind selected from the group consisting of α, β -unsaturated carboxylic acids and anhydrides thereof with a polyolefin, there can be mentioned a method (melting method) of heating and melting the polyolefin to a melting point or higher in the presence of a radical generator to effect a reaction; a known method such as a method (solution method) of dissolving the polyolefin in an organic solvent and then reacting the dissolved polyolefin by heating and stirring in the presence of a radical generator.

The weight average molecular weight of the acid-modified polyolefin resin (a) used in the present invention is preferably 3000 to 200000 as measured by high temperature GPC (gel permeation chromatography). More preferably 10000 or more, still more preferably 30000 or more, and particularly preferably 45000 or more. Further, more preferably 150000, and still more preferably 120000 or less. When the amount is within the above range, the acid-modified polyolefin is well dissolved in the (meth) acrylate (B1) and the (meth) acrylate (B2), and the phase inversion emulsification becomes easy. Further, the cohesion of the resin was sufficient, and the adhesive strength was good.

The measurement of the weight average molecular weight by high-temperature GPC can be performed by a known method using a commercially available apparatus using o-dichlorobenzene as a solvent and polystyrene as a standard substance. Specifically, the solvent used was o-dichlorobenzene, and the measurement was carried out at 140 ℃ using GPCI50-C plus type manufactured by Waters corporation. As the column, GMH6-HT and GMH6-HTL manufactured by Tosoh corporation were used. The weight average molecular weight was calculated using polystyrene of which molecular weight is known as a standard substance.

The acid-modified polyolefin resin (a) may be further subjected to chlorination modification. As the chlorinated polyolefin, an acid-modified chlorinated polyolefin obtained by chlorinating the acid-modified polyolefin resin is preferable. In the case of chlorinating the acid-modified polyolefin resin (a), the lower limit of the chlorine content is preferably 5 mass% or more, more preferably 8 mass% or more, further preferably 10 mass% or more, particularly preferably 12 mass% or more, and most preferably 14 mass% or more, from the viewpoints of solution stability and adhesion to a polyolefin substrate, a resin substrate, or a metal substrate. When the content is 5% by mass or more, the solution stability becomes good and the emulsification is easy. The upper limit is preferably 40% by mass or less, more preferably 38% by mass or less, still more preferably 35% by mass or less, particularly preferably 32% by mass or less, and most preferably 30% by mass or less. When the content is 40% by mass or less, the crystallinity of the acid-modified chlorinated polyolefin increases, and the adhesive strength tends to be strong.

The chlorine content of the acid-modified chlorinated polyolefin can be determined by titration based on JIS K-7229-1995.

The melting point of the acid-modified polyolefin resin (a) in the present invention is preferably 90 ℃ or lower as measured by a differential scanning calorimeter (hereinafter, DSC). More preferably 85 ℃ or lower, and particularly preferably 80 ℃ or lower. When the content is within the above range, the film-forming property in the baking at 80 ℃ is suitable, and the adhesiveness to a polyolefin substrate, the water resistance and the peel strength are good.

The melting point by DSC in the present invention can be measured according to JIS K7121-2012, and can be measured, for example, under the following conditions. About 5mg of the sample was kept at 150 ℃ for 10 minutes in a heated and melted state by using a DSC measuring apparatus (manufactured by Seiko electronics Co., Ltd.), then, the temperature was decreased at a rate of 10 ℃/min, the sample was stably kept at-50 ℃, and further, the temperature was increased at 10 ℃/min up to 150 ℃, and the melting peak temperature at the time of melting was measured, and the temperature was evaluated as the melting point. The melting points in the examples described below were measured under the conditions described above.

< (meth) acrylate copolymer (B) >

The (meth) acrylate copolymer (B) used in the present invention contains, as copolymerization components, a copolymer of a (meth) acrylate (B1) in which the ester moiety is a hydrocarbon group having 12 or more carbon atoms and a (meth) acrylate (B2) in which the ester moiety is a hydrocarbon group having 11 or less carbon atoms. Hereinafter, these compounds are also referred to simply as (B1) and (B2).

By containing (B1) and (B2), the acid-modified polyolefin resin (a) can be sufficiently dissolved, phase inversion emulsification becomes easy, and adhesion to a polyolefin substrate is good despite containing an acrylic acid component. Further, the compatibility with other resins in the coating film is also good due to the high affinity with resins other than polyolefin.

The content of the (meth) acrylate copolymer (B) is preferably in the range of 40 to 250 parts by mass with respect to 100 parts by mass of the acid-modified polyolefin resin (a). More preferably 80 to 200, and still more preferably 100 to 150. (B) When the content of (b) is in the range of 40 to 250, the phase inversion emulsification of the acid-modified polyolefin resin (A) is easy and the adhesion to the polyolefin resin substrate is good.

< (meth) acrylic ester (B1) >, and

examples of the (meth) acrylate (B1) in which the ester moiety is a hydrocarbon group having 12 or more carbon atoms include lauryl (meth) acrylate, tridecyl (meth) acrylate, tetradecyl (meth) acrylate, pentadecyl (meth) acrylate, hexadecyl (meth) acrylate, heptadecyl (meth) acrylate, stearyl (meth) acrylate, isostearyl (meth) acrylate, nonadecyl (meth) acrylate, eicosyl (meth) acrylate, heneicosyl (meth) acrylate, docosyl (meth) acrylate, tricosyl (meth) acrylate, tetracosyl (meth) acrylate, pentacosyl (meth) acrylate, hexacosyl (meth) acrylate, heptacosyl (meth) acrylate, and mixtures thereof, Acrylic monomers such as octacosyl (meth) acrylate, nonacosyl (meth) acrylate, triacontyl (meth) acrylate, hentriacontyl (meth) acrylate, dotriacontanyl (meth) acrylate, tetratriacontyl (meth) acrylate, and pentadecanyl (meth) acrylate. The hydrocarbon group may be linear or branched, and may have a cyclic structure. These monomers may be used alone in 1 kind or in combination of 2 or more kinds.

The ester moiety of the (meth) acrylic acid ester (B1) has 12 or more carbon atoms, preferably 35 or less carbon atoms, and more preferably 18 or less carbon atoms. When the number of carbon atoms is 12 to 35, the solubility of the acid-modified polyolefin resin (a) and the polymerizability at the time of emulsion polymerization are suitable.

< (meth) acrylic ester (B2) >, and

examples of the (meth) acrylic ester (B2) in which the ester moiety used in the present invention is a hydrocarbon group having 11 or less carbon atoms include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, cyclohexyl (meth) acrylate, t-butylcyclohexyl (meth) acrylate, isobornyl (meth) acrylate, and dicyclopentanyl (meth) acrylate. These monomers may be used alone in 1 kind or mixed in 2 or more kinds.

The number of carbon atoms of the ester moiety in the (meth) acrylic acid ester (B2) is preferably 1 to 10, more preferably 8. By setting the carbon number to 1 to 10, the solubility of the acid-modified polyolefin is optimized, and phase inversion emulsification and emulsion polymerization are facilitated.

The mass ratio of the (meth) acrylate (B1) in which the ester moiety is a hydrocarbon group having 12 or more carbon atoms to the (meth) acrylate (B2) in which the ester moiety is a hydrocarbon group having 11 or less carbon atoms, which is contained in the (meth) acrylate copolymer (B) used in the present invention, is preferably in the range of 70/30 to 20/80. More preferably 60/40-40/60. When the amount is within the above range, the solubility of the acid-modified polyolefin resin (A) is improved, and the phase inversion emulsification is facilitated. In addition, the (meth) acrylate copolymer has improved affinity for polyolefin substrates, and exhibits good adhesion to polyolefin substrates.

< polar-containing monomer (B3) >)

The (meth) acrylate copolymer (B) used in the present invention may further be obtained by copolymerizing a polar monomer (B3) (hereinafter, may be abbreviated as (B3)). (B3) The (B3) is different from the (B1) and (B2) and includes (meth) acrylate, (meth) acrylic acid and (meth) acrylamide having a polar group in the ester portion, and 1 or more selected from them can be used. As the polar group of the acrylate having a polar group in the ester portion, a hydroxyl group, a carboxyl group, a phosphoric acid group, an amino group, an amide group, an ether group, an epoxy group, or the like is preferably used. Among them, amide groups and hydroxyl groups are preferably used, and hydroxyl groups are more preferably used. Examples of the acrylate having a polar group in the ester portion include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, dicyclopentenyl (meth) acrylate, glycidyl (meth) acrylate, methyl glycidyl (meth) acrylate, 3, 4-epoxycyclohexane methyl methacrylate, tetrahydrofurfuryl (meth) acrylate, polyethylene glycol mono (meth) acrylate, polyethylene glycol di (meth) acrylate, polypropylene glycol mono (meth) acrylate, polypropylene glycol di (meth) acrylate, polytetramethylene glycol mono (meth) acrylate, polytetramethylene glycol di (meth) acrylate, dimethylaminoethyl (meth) acrylate, glycidyl (meth) acrylate, and the like, Diethylaminoethyl (meth) acrylate, and the like. Examples of the acrylamide compound include (meth) acrylamide, dimethyl (meth) acrylamide, diethyl (meth) acrylamide, and dimethylaminopropyl (meth) acrylamide. Preferably, 1 or more species thereof are used, and more preferably, 2 or more species having the same polar group are used. By using these compounds (B3) in combination with (B1) and (B2), the adhesion to the polar substrate and the surface layer coating material was improved as compared with the case of (B1) and (B2) alone. Further, (B3) alone has poor solubility in the acid-modified polyolefin resin (a), and the combined use of (B1) and (B2) improves compatibility with the acid-modified polyolefin resin (a).

The amount of (B3) used in the present invention is preferably 1 to 40% by weight based on the amount of (meth) acrylate copolymer (B). More preferably 2% by mass or more, still more preferably 4% by mass or more, and particularly preferably 6% by mass or more. Further, it is more preferably 30% by mass or less, still more preferably 25% by mass or less, and most preferably 20% by mass or less. When the amount is within the above range, the solubility of the acid-modified polyolefin (A) is improved, and phase inversion emulsification is facilitated. Further, the polar group content in the (meth) acrylate copolymer (B) is optimized, whereby the adhesion of the target composition to the polyolefin substrate and the adhesion of the polar substrate to the surface layer coating paint are improved.

In the present application, "(meth) acrylate" means "acrylate or methacrylate", "(meth) acrylic acid" means "acrylic acid or methacrylic acid", and "(meth) acryl" means "acryl or methacryl". "(meth) acrylamide" means "acrylamide or methacrylamide".

The (meth) acrylate copolymer (B) of the present invention may contain a polymerizable monomer other than (B1), (B2), and (B3). Examples of the polymerizable monomer other than (B1), (B2), and (B3) include styrene monomers such as styrene, α -methylstyrene, p-methylstyrene, and divinylbenzene. Further, as monomers which can be used in combination other than the above, vinyl acetate and the like can be cited. These monomers may be used alone in 1 kind or in combination of 2 or more kinds.

The glass transition temperature (Tg) of the (meth) acrylate copolymer (B) is preferably in the range of-40 ℃ to 80 ℃. More preferably-30 ℃ or higher, and still more preferably-20 ℃ or higher. Further, it is more preferably 60 ℃ or lower, and still more preferably 50 ℃ or lower. When the amount is within the above range, the flexibility of the coating film is optimized, bleeding of other components is suppressed, and the water resistance and the appearance of the coating film are improved. Further, the film forming property of the coating film during baking at 80 ℃ was also optimized, and the adhesion to polyolefin substrates, water resistance, and peel strength were good.

In order to design the (meth) acrylate copolymer (B) having a desired Tg, the mixing ratio of the (meth) acrylate monomer and the polar group-containing monomer is determined in consideration of the glass transition temperature of a homopolymer obtained when the (meth) acrylate monomer and the polar group-containing monomer are homopolymerized (hereinafter, sometimes referred to as "Tg of homopolymer").

Specifically, the Tg of the (meth) acrylate copolymer (B) can be calculated by using the formula (FOX formula) for calculating the theoretical Tg of the (meth) acrylate copolymer.

1/Tg ═ C1/Tg1+ C2/Tg2+ … + Cn/Tgn: (FOX type)

[ in the calculation formula (FOX formula), Tg is the theoretical Tg of the (meth) acrylate copolymer, Cn is the weight proportion of the monomer n contained in the monomer mixture of the (meth) acrylate copolymer (B), Tgn is the Tg of the homopolymer of the monomer n, and n is the number of monomers constituting the (meth) acrylate copolymer (B) and is a positive integer. ]

For example, lauryl methacrylate (Tg208.15K, 46% by mass) was used as (B1), cyclohexyl methacrylate (Tg339.15K, 46% by mass) was used as (B2), 2-hydroxyethyl methacrylate (Tg328.15K, 4% by mass) was used as (B3),

the calculation formula when 4-hydroxybutyl acrylate (tg233.15k, 4% by mass) was used is shown below. The theoretical Tg of the copolymer was calculated to be 259.1(K), which was-14.1 ℃ in terms.

1/Tg＝0.46/208.15+0.46/339.15+0.04/328.15+0.04/233.15

In the present invention, Tg is defined as the theoretical Tg (. degree. C.) determined from the above calculation formula.

The Tg of the homopolymer of the (meth) acrylate monomer and the polar group-containing monomer can be a value described in the literature. As such documents, for example, the following documents can be referred to: (meth) acrylate catalog of Kyoeisha chemical company, acrylate catalog of Mitsubishi chemical company; and Beigang Xiu, the book of macromolecules, 1997, 168-169, New Polymer library 7, which is imported from synthetic resins for coatings.

< surfactant >

The aqueous resin composition of the present invention may contain a surfactant in a range not to impair the performance of the present invention. Examples of the surfactant include nonionic surfactants, anionic surfactants, cationic surfactants, and amphoteric surfactants. Among these, from the viewpoint of the particle size of the dispersed particles and the water resistance of the coating film obtained from the target composition, a nonionic surfactant or an anionic surfactant is preferably used, and a nonionic surfactant is more preferably used.

Examples of the nonionic surfactant include polyoxyethylene alkyl ethers, polyoxypropylene alkyl ethers, polyoxyethylene alkylphenyl ethers, polyoxypropylene alkylphenyl ethers, polyoxyethylene styrenated phenyl ethers, polyoxypropylene styrenated phenyl ethers, polyoxyethylene fatty acid esters, polyoxypropylene fatty acid esters, polyoxyethylene sorbitan fatty acid esters, polyoxypropylene sorbitan fatty acid esters, polyoxyethylene alkylamine ethers, polyoxypropylene alkylamine ethers, polyoxyethylene lanolin alcohol ethers, polyoxypropylene lanolin alcohol ethers, polyoxyethylene lanolin fatty acid esters, and polyoxypropylene lanolin fatty acid ester (polyoxyethylene oxypropylene) block copolymers. Examples thereof include EMULMIN series (manufactured by Sanyo chemical Co., Ltd.), NOIGEN series (manufactured by first Industrial pharmaceutical Co., Ltd.), Blaunon series (manufactured by Qingmu oil and fat industries, Ltd.), and the like.

As these nonionic surfactants, reactive surfactants having a polymerizable double bond in the molecule can be used. Examples thereof include ADEKA REASOAP ER-10, ER-20, ER-30 and ER-40 (all of which are manufactured by ADEKA Co., Ltd.).

Examples of the anionic surfactant include higher alkyl sulfates, alkylaryl polyoxyethylene sulfates, higher fatty acid salts, alkylaryl sulfonates, and alkyl phosphate salts. Examples thereof include Neocol series and HITENOL series (first Industrial pharmaceutical Co., Ltd.).

As these anionic surfactants, reactive surfactants having a polymerizable double bond in the molecule can be used. Examples thereof include ADEKA REASOAPNE-10, NE-20, NE-30, NE-40, SE-10N (all of the above are manufactured by ADEKA Co., Ltd.), Aquaron RN-20, RN-30, RN-50, HS-10, HS-20 (all of the above are manufactured by first Industrial pharmaceutical Co., Ltd.), ェレミノ - ル JS-2, ェレミノ ー ル RS-30 (all of the above are manufactured by Sanyo chemical Co., Ltd.), and the like.

The surfactant can be used alone in 1 kind or mixed with 2 or more kinds.

In the present invention, the surfactant is preferably used in an amount of 5 to 60 parts by mass based on 100 parts by mass of the acid-modified polyolefin resin (a) from the viewpoint of easy phase inversion emulsification and water resistance of the coating film. More preferably 40 parts by mass or less, and still more preferably 30 parts by mass or less. Further, it is more preferably 20 parts by mass or less.

< basic Compound >

In the present invention, the composition may further contain a basic compound. In addition, in the production of the aqueous resin composition of the present invention, a basic compound may be used, and for example, when the acid-modified polyolefin resin (a) is subjected to phase inversion emulsification, the basic compound may be allowed to coexist. The dispersibility of the acid-modified polyolefin resin (a) can be improved by allowing it to exist in the system. Examples of the basic compound include inorganic basic compounds such as sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, and ammonium carbonate; amines such as triethylamine, N-dimethylethanolamine, aminoethanolamine, N-methyl-N, N-diethanolamine, isopropylamine, iminodipropylamine, ethylamine, diethylamine, 3-ethoxypropylamine, 3-diethylaminopropylamine, sec-butylamine, propylamine, methylaminopropylamine, methyliminodipropylamine, 3-methoxypropylamine, monoethanolamine, diethanolamine, triethanolamine, morpholine, N-methylmorpholine, N-ethylmorpholine, 2-amino-2-methyl-1-propanol, and 2-dimethylamino-2-methyl-1-propanol, and ammonia.

The amount of the basic compound added is preferably 0.3 to 4.0 times the chemical equivalent of the carboxyl group of the acid-modified polyolefin resin (A), and more preferably 0.7 to 2.5 times the chemical equivalent. When the amount is less than 0.3 times the chemical equivalent, the effect of the presence of the basic compound may not be observed.

On the other hand, if the amount exceeds 4.0 times the chemical equivalent, the residual amount in the dried product of the target composition may be too large.

The aqueous resin composition of the present invention can be obtained by dissolving the acid-modified polyolefin resin (a) in the mixed solution of (B1) and (B2), and subjecting the solution to phase inversion emulsification and polymerization reaction without using an organic solvent. The organic solvent is not used means that the organic solvent in the aqueous dispersion is 0.5% by mass or less, more preferably 0.1% by mass or less, still more preferably 0.01% by mass or less, still more preferably 0.001% by mass or less, and particularly preferably 0% by mass. Since no organic solvent is used, the production process can be simplified without concentration and degassing, and the production cost and time can be reduced. Specifically, the resin composition can be obtained by phase inversion emulsification of a (meth) acrylate solution of the acid-modified polyolefin resin (a) and polymerization of the (meth) acrylate solution with the (meth) acrylate. It is preferable to efficiently carry out the polymerization reaction using a polymerization initiator. The polymerization initiator used in the usual emulsion polymerization is preferably used in a conventional amount. Examples of the polymerization initiator include potassium persulfate, ammonium persulfate, and hydrogen peroxide; azo initiators such as 4, 4 '-azobis (4-cyanovaleric acid), 2, 2' -azobis [ N- (2-carboxyethyl) -2-methylpropionamide ], 2, 2 '-azobis [ 2-methyl-N- [2- (1-hydroxybutyl) ] propionamide ], 22' -azobis [ 2-methyl-N- (2-hydroxyethyl) propionamide ], and the like; peroxide initiators such as benzoyl peroxide, t-butyl peroxy-2-ethylhexanoate, 1-bis (t-butylperoxy) -3, 3, 5-trimethylcyclohexane, t-butyl peroxybenzoate, di-t-butyl peroxide, t-butyl hydroperoxide, cumene hydroperoxide, p-menthane hydroperoxide and diisopropylbenzene hydroperoxide. These may be used alone in 1 kind or in combination of 2 or more kinds. Further, a redox initiator can be used, and examples thereof include a combination of the above-mentioned polymerization initiator and a reducing agent (for example, a low ionic valence salt such as sulfite, bisulfite, cobalt, iron, and copper).

The polymerization conditions may be set as appropriate depending on the type of polymerizable monomer and polymerization initiator used, and the polymerization temperature is usually 20 to 100 ℃ and preferably 50 to 90 ℃. The polymerization time is usually 1 to 8 hours. In order to rapidly carry out the polymerization, it is preferable to replace the atmosphere in the polymerization system with an inert gas such as nitrogen gas in advance.

The Z-average particle diameter of the resin particles in the aqueous resin composition obtained as described above is preferably 10nm to 500nm, and more preferably 200 nm. When the average particle diameter exceeds 500nm, defects may occur in the coating film after coating, adversely affecting various physical properties, and it is difficult to use the coating composition particularly for surface coating, which is not preferable.

The aqueous resin composition of the present invention can be used as it is as a varnish, but can be used by blending various coating additives and other resin emulsions to such an extent that adhesion to polyolefin substrates is not inhibited, for the purpose of further modifying coating properties, for example, film formability, coating hardness, weather resistance, flexibility, etc. For example, film-forming aids such as propylene glycol monopropyl ether, dipropylene glycol monomethyl ether, and butyl propylene glycol, defoaming agents, anti-sagging agents, wetting agents, ultraviolet absorbers, and the like can be used. In particular, the coating film can be used by blending an acrylic emulsion or a polyurethane emulsion to improve coating film performances such as weather resistance, water resistance, coating film strength, flexibility, and the like.

In addition, in the aqueous resin composition of the present invention, a tackifier, for example, an aqueous dispersion liquid such as rosin, dammar resin, polymerized rosin, hydrogenated rosin, ester rosin, rosin-modified maleic acid resin, polyterpene resin, petroleum resin, cyclopentadiene resin, phenol resin, xylene resin, coumarone-indene resin, may be added as needed, whereby the drying property of a coating film and the adhesion to a polyolefin substrate can be improved. The amount of the additive is preferably 5 to 100 parts by mass, more preferably 10 to 50 parts by mass, of the solid content, based on 100 parts by mass of the solid content of the resin composition. When the amount is less than 5 parts by mass, the effect of addition may not be exhibited. On the other hand, if the amount exceeds 100 parts by mass, the addition amount is too large, which may adversely cause a decrease in adhesion.

The aqueous resin composition of the present invention can be preferably used for various kinds of paints or inks for olefin substrates including polypropylene, adhesives, sealants, primers, etc., but is not limited to these substrates, and can be applied to other plastics, wood, metals, etc., for example. Examples of the polyolefin substrate include films, sheets, and molded bodies. The coating method is not particularly limited. The coating film after coating may be dried at room temperature, but is preferably dried at 30 to 120 ℃, more preferably at 60 to 100 ℃.

[ examples ]

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

(1) Determination of the weight average molecular weight based on high temperature GPC

The solvent was o-dichlorobenzene and the reaction was carried out at 140 ℃ using GPC150-C Plus type manufactured by Waters corporation (column: GMH6-HT + GMH6-HTL manufactured by Tosoh corporation). The weight average molecular weight was calculated using polystyrene of known molecular weight as a standard.

(2) Melting point determination based on Differential Scanning Calorimetry (DSC)

About 5mg of a sample was kept at 150 ℃ for 10 minutes in a molten state by a DSC measuring apparatus (manufactured by Seiko electronics Co., Ltd.) based on JIS K7121-2012, and then cooled at a rate of 10 ℃/min, and after the sample was stably kept at-50 ℃, when the sample was further melted at a temperature of 10 ℃/min to 150 ℃, the melting peak temperature at the time of melting was measured, and the temperature was evaluated as a melting point.

(3) Measurement of z-average particle diameter (hereinafter, simply referred to as average particle diameter)

The average particle diameter (Z-average particle diameter) based on the intensity distribution was measured by a dynamic light scattering method using "Zetasizer Nano-ZS Model ZEN 3600" manufactured by Malvern corporation. The solid content of the aqueous dispersion composition was adjusted to a concentration of 0.05g/L, and the value was measured 3 times at 25 ℃ and taken as the average value thereof.

Production example 1

280g of a propylene-butene copolymer (having a propylene content of 70 mol% and a butene content of 30 mol%), 20g of maleic anhydride, 7g of dicumyl peroxide and 420g of toluene were charged into an autoclave equipped with a stirrer, and the autoclave was purged with nitrogen for about 5 minutes and then heated and stirred to react at 140 ℃ for 5 hours. After the reaction was completed, the reaction solution was added to a large amount of methyl ethyl ketone to precipitate a resin. The resin was further washed with methyl ethyl ketone several times to remove unreacted maleic anhydride. The obtained resin was dried under reduced pressure to obtain a solid substance (PO-1) of the acid-modified polyolefin resin. As a result of measurement by infrared absorption spectrum, the total content of the maleic anhydride component and the maleic acid component was 1.3% by mass. The weight average molecular weight by high temperature GPC was 80000, and the melting point by DSC was 70 ℃.

Production example 2

280g of a propylene-ethylene copolymer (having a propylene content of 94.1 mol% and an ethylene content of 5.9 mol%), 14g of maleic anhydride, 5.6g of dicumyl peroxide and 420g of toluene were placed in an autoclave equipped with a stirrer, and after about 5 minutes of replacement with nitrogen gas, the reaction was carried out at 140 ℃ for 5 hours while heating and stirring. After the reaction, the reaction solution was put into a large amount of methyl ethyl ketone to precipitate the resin. The resin was further washed with methyl ethyl ketone several times to remove unreacted maleic anhydride. After drying under reduced pressure, 280g of the obtained maleic anhydride-modified polyolefin resin and 2520g of chloroform were placed in an autoclave equipped with a stirrer, and after nitrogen exchange for about 5 minutes, the resin was sufficiently dissolved by heating at 110 ℃. Subsequently, 1.4g of t-butyl peroxy-2-ethylhexanoate was added, and a predetermined amount of chlorine gas was blown in. Chloroform as a reaction solvent was distilled off under reduced pressure and dried, thereby obtaining a solid substance (CPO-1) of the acid-modified chlorinated polyolefin resin having a chlorine content of 18 mass%, a weight average molecular weight of 100000, a melting point by DSC of 85 ℃, and a maleic anhydride content of 0.9 mass%.

Example 1 (production of aqueous resin composition (a))

100g of the acid-modified polyolefin resin obtained in production example 1, 46g of cyclohexyl methacrylate, 46g of lauryl methacrylate, 4g of 2-hydroxyethyl methacrylate, 4g of 4-hydroxybutyl methacrylate, 15g of polyoxyethylene styrenated phenyl ether (product of first Industrial pharmaceutical Co., Ltd.; trade name "NOIGENEA-197", nonionic surfactant) and 1.5g of sodium dioctylsuccinate (product of first Industrial pharmaceutical Co., Ltd.; trade name "Neocol P", anionic surfactant) were charged into a 2L four-necked flask equipped with a condenser, a thermometer, a stirrer and a dropping funnel, and sufficiently dissolved while maintaining the temperature at 100 ℃. To the solution was added 3.2g of N, N-dimethylethanolamine, and the mixture was stirred for 15 minutes. Subsequently, 500g of deionized water previously heated to 95 ℃ was added dropwise from a dropping funnel over 30 minutes while stirring vigorously, to thereby effect phase inversion emulsification of the acid-modified polyolefin resin. After the emulsion was cooled to 80 ℃, nitrogen gas was introduced, whereby the inside of the system was sufficiently replaced with nitrogen gas. Subsequently, an aqueous solution of 0.6g of ammonium persulfate dissolved in 30g of deionized water was added while maintaining 80 ℃ and polymerization was started under a nitrogen stream. Under a nitrogen stream, the reaction was carried out at 80 ℃ for 8 hours, followed by cooling, to obtain an aqueous resin composition (a) having a resin concentration (solid content) of 30 mass% and an average particle diameter of resin particles of 140 nm. The theoretical Tg of the (meth) acrylate copolymer (B) was-14.1 ℃.

Example 2 (production of aqueous resin composition (b))

An aqueous resin composition (b) having a resin concentration (solid content) of 30 mass% and an average particle diameter of resin particles of 160nm was obtained in the same manner as in example 1, except that the kinds of the respective components were changed to the components shown in table 1. The theoretical Tg of the (meth) acrylate copolymer (B) was 46.5 ℃.

Example 3 (production of aqueous resin composition (c))

An aqueous resin composition (c) having a resin concentration (solid content) of 30 mass% and an average particle diameter of resin particles of 180nm was obtained in the same manner as in example 1, except that the amounts of the respective components were changed to the components shown in table 1. The theoretical Tg of the (meth) acrylate copolymer (B) was-14.1 ℃.

Example 4 production of aqueous resin composition (d)

An aqueous resin composition (d) having a resin concentration (solid content) of 30 mass% and an average particle diameter of resin particles of 100nm was obtained in the same manner as in example 1, except that the amounts of the respective components were changed to the components shown in Table 1. The theoretical Tg of the (meth) acrylate copolymer (B) was-14.1 ℃.

Example 5 (production of aqueous resin composition (e))

An aqueous resin composition (e) having a resin concentration (solid content) of 30 mass% and an average particle diameter of resin particles of 140nm was obtained in the same manner as in example 1, except that the amounts of the respective components were changed to the components shown in Table 1. The theoretical Tg of the (meth) acrylate copolymer (B) was-30.9 ℃.

Example 6 (production of aqueous resin composition (f))

An aqueous resin composition (f) having a resin concentration (solid content) of 30 mass% and an average particle diameter of resin particles of 130nm was obtained in the same manner as in example 1, except that the amounts of the respective components were changed to the components shown in Table 1. The theoretical Tg of the (meth) acrylate copolymer (B) was 46.5 ℃.

Example 7 (production of aqueous resin composition (g))

An aqueous resin composition (g) having a resin concentration (solid content) of 30 mass% and an average particle diameter of resin particles of 180nm was obtained in the same manner as in example 1, except that the amounts of the respective components were changed to the components shown in Table 1. The theoretical Tg of the (meth) acrylate copolymer (B) was 27.4 ℃.

Example 8 (production of aqueous resin composition (h))

An aqueous resin composition (h) having a resin concentration (solid content) of 30 mass% and an average particle diameter of resin particles of 180nm was obtained in the same manner as in example 1, except that the amounts of the respective components were changed to the components shown in Table 1. The theoretical Tg of the (meth) acrylate copolymer (B) was-7.9 ℃.

Example 9 (production of aqueous resin composition (i))

An aqueous resin composition (i) having a resin concentration (solid content) of 30 mass% and an average particle diameter of resin particles of 150nm was obtained in the same manner as in example 1, except that the amounts of the respective components were changed to the components shown in table 1. The theoretical Tg of the (meth) acrylate copolymer (B) was-15.2 ℃.

Example 10 (production of aqueous resin composition (j))

An aqueous resin composition (i) having a resin concentration (solid content) of 30 mass% and an average particle diameter of resin particles of 110nm was obtained in the same manner as in example 1, except that the amounts of the respective components were changed to the components shown in Table 1. The theoretical Tg of the (meth) acrylate copolymer (B) was-41.2 ℃.

Comparative example 1 (production of aqueous resin composition (k))

100g of the acid-modified polyolefin obtained in production example 1, 90g of toluene, 90g of isopropyl alcohol, and 15g of polyoxyethylene styrenated phenyl ether (trade name "NOIGENEA-197", manufactured by first Industrial pharmaceutical Co., Ltd., nonionic surfactant) were charged into a 2L four-necked flask equipped with a condenser, a thermometer, a stirrer, and a dropping funnel, and sufficiently dissolved while being maintained at 100 ℃. To the solution was added 3.2g of N, N-dimethylethanolamine and stirred for 15 minutes. Then, 300g of deionized water previously heated to 95 ℃ was added dropwise from a dropping funnel over 30 minutes while stirring vigorously to emulsify the acid-modified polyolefin in a phase inversion. This emulsion was cooled to 60 ℃ and the solvent was removed under reduced pressure, whereby an aqueous resin composition (k) having a resin concentration (solid content) of 30 mass% and an average particle diameter of resin particles of 130nm was obtained.

Comparative example 2 (production of aqueous resin composition (1))

An aqueous resin composition (1) having a resin concentration (solid content) of 30 mass% and an average particle diameter of resin particles of 130nm was obtained in the same manner as in example 1, except that the amounts of the respective components were changed to the components shown in Table 1. The theoretical Tg of the (meth) acrylate copolymer (B) was 78.9 ℃.

Comparative example 3 (production of aqueous resin composition (m))

An aqueous resin composition (m) having a resin concentration (solid content) of 30 mass% and an average particle diameter of resin particles of 180nm was obtained in the same manner as in example 1, except that the amounts of the respective components were changed to the components shown in table 1. The theoretical Tg of the (meth) acrylate copolymer (B) was 21.2 ℃.

The meanings of each marker in table 1 are as follows. LMA: lauryl methacrylate (Tg ═ 65 ℃), SMA: stearyl methacrylate (Tg ═ 38 ℃), CHMA: cyclohexyl methacrylate (Tg ═ 66 ℃), MMA: methyl methacrylate (Tg 105 ℃), EHMA: 2-ethylhexyl methacrylate (Tg ═ 10 ℃), HEMA: 2-hydroxyethyl methacrylate (Tg ═ 55 ℃), 4 HBA: 4-hydroxybutyl acrylate (Tg ═ 40 ℃), DMAA: dimethylacrylamide (Tg ═ 119 ℃), styrene (Tg ═ 100 ℃).

[ Table 1]

The following properties were evaluated using the aqueous resin compositions (a) to (m) obtained in examples 1 to 10 and comparative examples 1 to 3. The results are shown in table 1.

(1) Adhesion Property

To 100g of the aqueous resin composition, 2g of propylene glycol monomethyl ether was added as a film-forming aid, and 2g of "Dynol 604" (manufactured by Air Products Japan) was added as a wetting agent, and the mixture was stirred with a magnetic stirrer for 30 minutes. The emulsion was sprayed on a polypropylene plate (made by Japanese Test Panel) cleaned with isopropyl alcohol to give a dry coating film having a thickness of 10 μm. After drying at 80 ℃ for 3 minutes, a 2K polyurethane paint (Retan PG White III, manufactured by Kaisakusho paint Co., Ltd.) was sprayed as a protective film so that the protective film became 40 to 50 μm. After drying at 80 ℃ C.. times.30 minutes, the plate was left to stand in an atmosphere of 25 ℃ C.. times.60% relative humidity for 24 hours to prepare a test plate. 100 meshes reaching the substrate were formed on the test plate at 1mm intervals, and a glass tape was pressed thereon, and peeling was repeated 3 times at an angle of 90 degrees to the coated surface, and evaluated as ∘ when peeling was not performed, as Δ when peeling was performed the third time, and as x when peeling was performed the second time.

(2) Water resistance

The test plate obtained by the method (1) was immersed in warm water at 40 ℃ for 240 hours, and then the adhesion was evaluated by the same method as that of the method (1). Further, the presence or absence of the occurrence of blisters (floating or swelling of the coating film) was confirmed from the appearance of the coating film. The evaluation was ≈ when no peeling or bubbling occurred, Δ when no peeling or bubbling occurred, and ×, when peeling occurred.

(3) Peel strength

A test piece was prepared in the same manner as in the above (1) except that a 100 μm protective film was sprayed, and then the test piece was left to stand in an atmosphere of 25 ℃ x 60% relative humidity for a further 48 hours. Short strips of peel sheets were formed on the test plate at 1cm intervals, and a 50mm 180 DEG peel test was carried out at a speed of 50 mm/min by means of a tensile tester (Tencilon RTG-1310 manufactured by A & D Co.). The stress at the time of stretching was taken as the peel strength, and the average value of 5 tests was taken as the measurement result.

(4) Compatibility

For each aqueous resin composition, "Superflex 150 HS" (polyurethane emulsion manufactured by first industrial pharmaceutical co., ltd., solids content 38 mass%) and "Primal 2133" (acrylic emulsion manufactured by Rohm and Haas Japan, solids content 41.5 mass%) were mixed at a solids content of 1: 1 by mass ratio, and the mixed material was applied to a glass plate with a 50 μm applicator and dried at 80 ℃ for 30 minutes. The state of the glass plate after drying was visually observed, and evaluated as ∘when2 coating films were all transparent, as Δ when 1 coating film was turbid, and as ×, when 2 coating films were all turbid.

(5) High resin stability

The aqueous resin compositions obtained in the examples and comparative examples were concentrated to a resin concentration of 45 mass%, and the fluidity was confirmed from the appearance. The evaluation was "good" when the sample had fluidity, and "good" when the sample was viscous but had no fluidity.

[ examination of the results of Table 2 ]

As is clear from Table 2, the aqueous resin compositions (a) to (j) obtained in examples 1 to 10 exhibited high peel strength similar to that of the aqueous resin composition (k) of the polyolefin single dispersion at 80 ℃ baking, and were excellent in water resistance and stability of the high resin component. On the other hand, when the ratio of the acid-modified polyolefin to the (meth) acrylate copolymer and the components are outside the range of the present invention, the peel strength is low, and the adhesion to a polyolefin substrate and the water resistance are poor.