Aqueous polymer dispersions, coatings, primer compositions, and laminates

Abstract

Provided is an aqueous polymer dispersion that can form a coating film that maintains adhesion to a substrate even when subjected to high-temperature high-pressure washing. An aqueous polymer dispersion that is an aqueous polymer dispersion in which an olefin-based polymer (A) and an acrylic polymer (B) are dispersed in an aqueous medium, the acrylic polymer (B) having a glass transition temperature of 105°C or higher. In some examples, the acrylic polymer (B) can contain structural units derived from isobornyl methacrylate, the olefin-based polymer (A) and the acrylic polymer (B) can form composite particles, and the olefin-based polymer (A) can have a reactive group.

Description

Technical Field

[0001] This invention relates to aqueous polymer dispersions, coatings, primer compositions, and laminates. Background Technology

[0002] In recent years, environmentally friendly polymer compositions have attracted much attention. Among them, solvent-free, water-dispersible polymer compositions have garnered particular interest. Especially in the coatings industry, research on solvent-free polymer compositions is ongoing.

[0003] On the other hand, polyolefins, such as polypropylene and copolymers of propylene with other α-olefins, which are used as coating materials, are widely used in various fields due to their excellent mechanical properties, heat resistance, chemical resistance, and water resistance. However, when forming a coating film on polyolefins, the low polarity of polyolefins can make the coating film difficult to adhere.

[0004] Methods for improving adhesion to polyolefins include chemical treatment of the polyolefin surface with chemical reagents, surface oxidation treatment such as corona discharge treatment, plasma treatment, and flame treatment. However, these methods require specialized equipment. Furthermore, there is a concern that the improvement in adhesion may not be sufficient.

[0005] On the other hand, as coatings that improve adhesion to polyolefins, coatings formulated with modified olefin polymers such as chlorinated polyolefins, acid-modified polyolefins, and acid-modified chlorinated polyolefins are known. Such coatings include solvent-based coatings in which the modified olefin polymer is dissolved in an organic solvent and aqueous coatings dispersed in an aqueous medium. From the perspectives of safety, hygiene, and reducing environmental pollution, aqueous coatings are preferred.

[0006] However, waterborne coatings containing modified olefin polymers are still undergoing further improvements due to insufficient performance.

[0007] For example, Patent Document 1 discloses an aqueous polymer dispersion that uses a specific propylene polymer with a low melting point and low molecular weight and a specific propylene polymer with a high melting point and high molecular weight, which is also modified from an unsaturated organic acid derivative.

[0008] Patent document 2 discloses a composite polymer using an acrylic polymer and an olefin polymer modified by a specific free radical polymerizable monomer.

[0009] Patent document 3 discloses an aqueous dispersion composition containing a modified polyolefin, a polyolefin different from the modified polyolefin, a thickener, and an epoxy polymer.

[0010] Patent document 4 discloses an aqueous coating composition containing an olefin polymer and a hydroxyl-containing polymer having specific hydroxyl groups.

[0011] In addition, a dispersion of an aqueous polymer has been proposed, which is a composite of a modified polyolefin or graft copolymer with a polymer polymerized from a free radical polymerizable monomer, in order to improve the performance and storage stability of the aqueous polymer dispersion as a coating.

[0012] For example, Patent Document 5 discloses an aqueous polymer dispersion that can easily achieve excellent adhesion to polyolefin substrates such as polypropylene substrates and can be baked at low temperatures. It comprises an olefin polymer and a polymer of structural units derived from free radical polymerizable monomers with reactive functional groups, and has specific particle size and solubility.

[0013] [Existing technical documents]

[0014] [Patent Literature]

[0015] [Patent Document 1] Japanese Patent Application Publication No. 2008-031360

[0016] [Patent Document 2] International Publication No. 2017 / 213192

[0017] [Patent Document 3] International Publication No. 2019 / 181336

[0018] [Patent Document 4] Japanese Patent Application Publication No. 2019-210308

[0019] [Patent Document 5] International Publication No. 2019 / 112039 Summary of the Invention

[0020] [The problem the invention aims to solve]

[0021] However, while patent document 1 discloses an aqueous polymer dispersion containing propylene polymers and other resins, it does not explore how to obtain excellent high-temperature and high-pressure properties. Patent documents 2, 4, and 5, although using composite resins of olefin polymers and acrylic polymers, suffer from the problem of low glass transition temperatures of acrylic polymers, leading to decreased adhesion to the substrate at high temperatures. Patent document 3 uses olefin polymers and epoxy resins; however, the use of epoxy resin results in poor weather resistance, causing coating discoloration and deterioration.

[0022] When automotive exterior parts and industrial components are exposed to physical and thermal stresses such as steam cleaning or high-pressure car washes, the coating peels off, which not only damages the appearance of the product but also loses its "function" of protecting the substrate.

[0023] In addition, in order to maintain adhesion to the substrate even during high-temperature and high-pressure cleaning, the aqueous polymer dispersion needs to have a certain degree of dispersibility, as well as water resistance and film-forming properties of the coating.

[0024] The purpose of this invention is to provide an aqueous polymer dispersion that can form a coating film that maintains adhesion to the substrate even during high-temperature and high-pressure cleaning.

[0025] Technical solutions to the problem

[0026] Through in-depth research, the inventors discovered that by using an aqueous polymer dispersion containing an olefinic polymer and an acrylic polymer with a glass transition temperature greater than a specific value, a coating film that maintains adhesion to the substrate even after high-temperature, high-pressure cleaning can be formed, thus achieving the present invention. The adhesion to the substrate after high-temperature, high-pressure cleaning is difficult to predict based on the typical adhesion of coatings to the substrate; the aforementioned effect discovered by the inventors can be described as a highly predictable effect based on existing technologies.

[0027] That is, the present invention has the following aspects.

[0028] [1] An aqueous polymer dispersion comprising an olefin polymer (A) and an acrylic polymer (B) dispersed in an aqueous medium.

[0029] The acrylic polymer (B) has a glass transition temperature of 105°C or higher.

[0030] The mass ratio of the olefin polymer (A) to the acrylic polymer (B) is (A):(B) = 25:75~99:1.

[0031] [2] According to the aqueous polymer dispersion of [1], wherein the acrylic polymer (B) contains structural units derived from isobornyl methacrylate.

[0032] [3] According to the aqueous polymer dispersion of [1] or [2], wherein the olefin polymer (A) and the acrylic polymer (B) form composite particles.

[0033] [4] The aqueous polymer dispersion according to any one of [1] to [3], wherein the olefin polymer (A) comprises at least one selected from the group consisting of ethylene-propylene copolymer, ethylene-propylene-butene copolymer and propylene-butene copolymer.

[0034] [5] An aqueous polymer dispersion according to any one of [1] to [4], wherein the olefin polymer (A) has reactive groups.

[0035] [6] According to the aqueous polymer dispersion of [5], wherein the reactive group comprises at least one selected from the group consisting of carboxyl, epoxy, isocyanate, sulfonic acid and hydroxyl groups.

[0036] [7] An aqueous polymer dispersion according to any one of [1] to [6], wherein the average particle size of the aqueous polymer dispersion is less than 500 nm.

[0037] [8] A coating, characterized in that it contains an aqueous polymer dispersion as described in any one of [1] to [7].

[0038] [9] A primer composition, characterized in that it contains an aqueous polymer dispersion according to any one of [1] to [7].

[0039]

[10] A laminate, characterized in that it comprises a substrate and a layer disposed on the substrate, which is formed by drying an aqueous polymer dispersion of any one of [1] to [7].

[0040]

[11] The laminate according to

[10] , wherein the substrate is a polyolefin substrate.

[0041] [The effects of the invention]

[0042] The aqueous polymer dispersion of the present invention can form a coating that maintains adhesion to the substrate even during high-temperature and high-pressure cleaning. Attached Figure Description

[0043] Figure 1 The method for evaluating adhesion during high-temperature and high-pressure cleaning is shown in the examples.

[0044] Figure 2 An example of a coating that peels off during an evaluation of adhesion under high temperature and high pressure cleaning.

[0045] Symbol Explanation

[0046] 10. Nozzles of high-temperature and high-pressure cleaning test equipment

[0047] 11 Coating

[0048] 12. Cross-shaped incision

[0049] d High-pressure hot water spray distance

[0050] f. Coating peeling Detailed Implementation

[0051] The present invention will now be described in detail. The following embodiments are merely illustrative examples and do not imply that the invention is limited to these embodiments. The present invention can be implemented in various ways without departing from its spirit.

[0052] It should be noted that, within the scope of this specification and the claims of the patent, the numerical range represented by "~" includes the range where the values ​​before and after the "~" are used as the lower and upper limits. For example, A~B is equivalent to A above and B below.

[0053] The numerical ranges of content, various physical properties, and morphological values ​​disclosed in this specification can be arbitrarily combined with their lower and upper limits to form new numerical ranges.

[0054] Furthermore, in this invention and in this specification, the following terms have the following meanings.

[0055] "(Meth)acrylic acid" is a general term for acrylic acid and methacrylic acid.

[0056] "(Meth)acrylic acid" is a general term for acrylic acid and methacrylic acid.

[0057] "(Meth)acrylate" is a general term for "acrylate" and "methacrylate".

[0058] A "dispersion" refers to a substance that contains olefin polymers (A), acrylic polymers (B), and an aqueous medium in a dispersed state. Such substances that disperse polymers in an aqueous medium are called "aqueous polymer dispersions".

[0059] "Aqueous medium" refers to water, or a mixture of water and organic solvents.

[0060] "Dispersed state" refers to the fact that olefin polymer (A) and acrylic polymer (B) are insoluble in aqueous media and exist as particles or as composite particles, respectively.

[0061] "Dispersion" refers to the state in which dispersed particles are dispersed as extremely small single molecules, and can actually include the concept of a dissolved state.

[0062] "Copolymer" can be either random copolymer or block copolymer.

[0063] "Integration" refers to the combination of multiple polymers with different structures through chemical interactions (e.g., covalent bonds), physical interactions (e.g., intermolecular forces), or mechanical interactions; it is also called "composite".

[0064] "Composite particles" refer to particles that are integrally formed from olefin polymers (A) and acrylic polymers (B).

[0065] "Structural unit" refers to a unit that constitutes a polymer from monomers, that is, a structural unit formed by polymerizing monomers, or a structural unit that is modified by polymerizing the polymer so that a part of the structural unit is transformed into a structural unit of other structures.

[0066] "Monomer components" is a general term for monomer components that have polymerizable double bonds. Monomer components do not include polymerization initiators or polymerization solvents.

[0067] "Coating" refers to a film formed from the aqueous polymer dispersion of the present invention.

[0068] [Aqueous polymer dispersions]

[0069] The aqueous polymer dispersion in this embodiment is formed by dispersing an olefin polymer (A) and an acrylic polymer (B) in an aqueous medium. That is, the aqueous polymer dispersion contains an olefin polymer (A), an acrylic polymer (B), and an aqueous medium.

[0070] In addition to the olefin polymer (A), acrylic polymer (B) and aqueous medium, the aqueous polymer dispersion may, without impairing the effects of the present invention, further contain components other than the olefin polymer (A), acrylic polymer (B) and aqueous medium (hereinafter also referred to as "arbitrary components").

[0071] (Olefin polymer (A))

[0072] Olefin polymers (A) are polymers containing structural units derived from olefins. Olefin polymers (A) can be linear or branched.

[0073] The olefin polymer (A) may have reactive groups. Examples of reactive groups include carboxyl, epoxy, isocyanate, sulfonic acid, and hydroxyl groups. The olefin polymer (A) may have one or more reactive groups. Preferably, it includes at least one group selected from the group consisting of carboxyl, epoxy, isocyanate, sulfonic acid, and hydroxyl groups.

[0074] Examples of olefin-based polymers (A) include, for example, homopolymers of olefins (hereinafter referred to as "olefin-based homopolymers (A1)"), copolymers containing olefin monomer components (a2) (hereinafter referred to as "olefin-based copolymers (A2)"), and olefin-based composite polymers (A3). One of these may be used alone, or two or more may be used in combination.

[0075] Examples of olefins used in the olefin polymer (A) include ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, cyclopentene, cyclohexene, and norbornene. Among these olefins, propylene is preferred from the viewpoint of adhesion to olefin substrates. That is, from the viewpoint of adhesion to olefin substrates, propylene-based polymers having structural units derived from propylene are preferred as the olefin polymer (A).

[0076] Olefin homopolymer (A1) is a homopolymer of olefins. Examples of olefin homopolymers (A1) include any homopolymer of the olefin exemplified in the olefin polymer (A). Olefin homopolymer (A1) can be used alone or in combination with two or more olefins.

[0077] The olefin homopolymer (A1) can be an olefin homopolymer (A11) having reactive groups such as carboxyl (carboxylic acid group), epoxy group, isocyanate group, sulfonic acid group (sulfonyl), and hydroxyl group that can react with amino groups. The reactive group can be an anhydride structure of the carboxyl group. Maleic anhydride and acrylic acid are preferred as the reactive compounds.

[0078] Based on the viewpoint of excellent water resistance and adhesion, as an olefin homopolymer (A1), an olefin homopolymer (A11) with reactive groups is preferred.

[0079] The reactive group content of each 1g of olefin polymer (A) in the olefin homopolymer (A11) is preferably 0.01~1mmol / g, more preferably 0.05~0.5mmol / g, and even more preferably 0.1~0.3mmol / g.

[0080] When the reactive groups in olefin homopolymers (A11) are carboxyl groups or acidic groups such as their anhydrides or sulfonic acid groups, the higher the content of reactive groups, the higher the acid value of the olefin polymer (A). This tends to improve mechanical stability and enhance the polymerizability of free radical polymerizable monomers during manufacturing. Conversely, a lower content of acidic groups tends to increase the adhesion of coatings to olefin substrates and other substrates. The acid value of the olefin polymer (A) can be adjusted by controlling the content of acidic groups.

[0081] Neutralizing acidic groups with basic compounds tends to improve the mechanical stability of the olefin polymer (A). Examples of such basic compounds include inorganic bases such as sodium hydroxide and potassium hydroxide, as well as ammonia, triethylamine, diethylamine, ethanolamine, dimethylethanolamine, 2-methyl-2-amino-propanol, triethanolamine, morpholine, and pyridine. The neutralization rate of the acidic groups is not particularly limited as long as dispersibility in water is achieved; however, relative to the total amount of acidic groups contained in the olefin polymer (A), the neutralization rate is preferably 1 to 100 mol%, more preferably 50 mol% or more. A higher neutralization rate tends to improve the dispersibility of the olefin polymer (A) in water.

[0082] The olefin homopolymer (A1) can be a chlorinated olefin from which the olefin polymer is chlorinated. In this case, the degree of chlorination of the chlorinated olefin relative to the total mass of the olefin homopolymer (A1) is preferably 40% by mass or less, more preferably 30% by mass or less.

[0083] An olefin copolymer (A2) is a copolymer containing a monomer component (a2) of an olefin. The monomer component (a2) is a mixture containing two or more monomers, including at least one olefin. The monomer component (a2) may contain only two or more olefins, or it may contain one or more olefins and one or more monomers other than olefins (hereinafter referred to as "other monomers").

[0084] As an olefin, it is the same as the olefin exemplified as used in olefin-based polymers (A).

[0085] As for other monomers, any monomer that can copolymerize with olefins is acceptable; there are no particular limitations.

[0086] Examples of olefin copolymers (A2) include, for example, copolymers of ethylene and propylene; copolymers of at least one of ethylene and propylene and a monomer capable of copolymerizing with ethylene and propylene; copolymers of two or more α-olefins selected from the group consisting of α-olefins having 4 or more carbon atoms; copolymers of α-olefins having 2 or more carbon atoms and non-aromatic monomers other than α-olefins; copolymers of α-olefins having 2 or more carbon atoms and aromatic monomers or their hydrides; and conjugated diene block copolymers or their hydrides.

[0087] Monomers that can copolymerize with ethylene and propylene include, for example, α-olefins with 4 or more carbon atoms such as 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, cyclopentene, cyclohexene, and norbornene.

[0088] Examples of non-aromatic monomers other than α-olefins include vinyl acetate, acrylates, and methacrylates.

[0089] Examples of aromatic monomers include, for instance, aromatic vinyl monomers such as styrene.

[0090] There can be two or more comonomers other than olefins.

[0091] Among the many olefin copolymers (A2), ethylene-propylene copolymers, ethylene-propylene-butene copolymers, and propylene-butene copolymers are preferred. Olefin copolymers (A2) can be used alone or in combination of two or more types.

[0092] When the olefin copolymer (A2) has structural units derived from propylene, the proportion of structural units derived from propylene is preferably 50 mol% or more, more preferably 60 mol% or more, and even more preferably 70 mol% or more of all structural units derived from olefins in the olefin copolymer (A2). The upper limit of the proportion of structural units derived from propylene can be 100 mol%.

[0093] The olefin copolymer (A2) may be a chlorinated olefin from which the olefin polymer is chlorinated. In this case, the degree of chlorination of the chlorinated olefin relative to the total mass of the olefin copolymer (A2) is preferably 40% by mass or less, more preferably 30% by mass or less.

[0094] The olefin copolymer (A2) can be an olefin copolymer (A21) having reactive groups such as carboxyl (carboxylic acid), epoxy, isocyanate, sulfonic acid (sulfonyl), and hydroxyl groups that can react with amino groups. The reactive groups can be an anhydride structure of carboxyl groups. Maleic anhydride and acrylic acid are preferred as the reactive compounds.

[0095] Based on the viewpoint of excellent water adhesion resistance, as an olefin copolymer (A2), an olefin copolymer (A21) with reactive groups is preferred.

[0096] The reactive group content of each 1g of olefin polymer (A) in the olefin copolymer (A21) is preferably 0.01~1mmol / g, more preferably 0.05~0.5mmol / g or more, and even more preferably 0.1~0.3mmol / g.

[0097] When the reactive groups of an olefin copolymer (A21) are carboxyl groups or acidic groups such as their anhydrides or sulfonic acid groups, the higher the content of reactive groups, the higher the acid value of the olefin polymer (A). Therefore, it tends to improve mechanical stability and enhance the polymerizability of free radical polymerizable monomers during manufacturing. Conversely, a lower content of acidic groups tends to increase the adhesion of the coating to olefin substrates and other substrates. The acid value of the olefin polymer (A) can be adjusted by controlling the content of acidic groups.

[0098] The preferred olefin-based composite polymer (A3) is a composite polymer (a31) formed by integrating at least one polymer selected from the group consisting of olefin homopolymers (A1) and olefin copolymers (A2) with a hydrophilic polymer such as a polyether polymer. The olefin-based composite polymer (A3) can be used alone or in combination with two or more types.

[0099] Preferably, grafted polymers, core-shell structures, microphase separation structures, interpenetrating polymer network structures, etc., are formed by integrating multiple polymers with different structures.

[0100] Hydrophilic polymers are polymers that, when dissolved in water at 25°C at a concentration of 10% by mass, have an insoluble content of less than 1% by mass.

[0101] Hydrophilic polymers, as long as they are hydrophilic, can be synthetic polymers, natural polymers, or semi-synthetic polymers.

[0102] The number-average molecular weight (hereinafter, denoted as "Mn") of the hydrophilic polymer is preferably 300 or higher. The higher the Mn of the hydrophilic polymer, the greater the mechanical stability of the aqueous polymer dispersion containing the olefin polymer (A) and the acrylic polymer (B). There is no particular upper limit to the Mn of the hydrophilic polymer; for example, it can be 30,000 or less, or 10,000 or less. The Mn of the hydrophilic polymer can, for example, be 300 to 30,000 or 300 to 10,000.

[0103] The Mn content of hydrophilic polymers is a converted value based on a polystyrene standard curve determined by gel permeation chromatography (GPC). GPC determination can be performed using commercially available equipment with solvents such as tetrahydrofuran (THF) by known methods.

[0104] Hydrophilic polymers, such as polyether polymers, polyvinyl alcohol polymers, and polyvinylpyrrolidone polymers, can be used as synthetic polymers.

[0105] Hydrophilic polymers, which are natural macromolecules, can be used in the following ways: starch, gum arabic, astragalus gum, casein, gelatin, dextrin, etc.

[0106] Hydrophilic polymers that are semi-synthetic polymers can include, for example, carboxylated starch, cationic starch, dextrin, ethyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, cationic cellulose, etc.

[0107] As a hydrophilic polymer, it is preferred to synthesize hydrophilic polymers because the degree of hydrophilicity is easy to control and the properties are stable.

[0108] Hydrophilic polymers can be used alone or in combination of two or more. Among the many hydrophilic polymers, polyether polymers with high hydrophilicity are preferred. The average particle size of the aqueous polymer dispersion can be adjusted by the type and combination of hydrophilic polymers.

[0109] Polyether polymers can be manufactured, for example, by ring-opening polymerization of cyclic alkylene oxides or cyclic alkylene imides. Polyether polymers can be integrated with olefin polymers without bonding, but to prevent leakage from the coating film, integration with the olefin polymer is preferred.

[0110] Polyether polyols are compounds that have hydroxyl groups as reactive groups at both ends of a polymer having a polyether backbone. Polyether amines are compounds that have primary amino groups as reactive groups at one or both ends of a polymer having a polyether backbone.

[0111] Polyether polymers that integrate olefin-based polymers are preferably polyetheramines. Examples of polyetheramines include Huntsman's "JEFFAMINE" M series, D series, ED series and "SURFONAMINE" L series.

[0112] The polyether polymer preferably has hydrophilic structural units such as polyethylene oxide or polyethyleneimine and hydrophobic structural units such as polypropylene oxide or polypropyleneimine. The polyether polymer is further preferably composed of structural units derived from polyethylene oxide and structural units derived from polypropylene oxide.

[0113] The HLB (Hydrophile Lipophile Balance) of polyether polymers can be adjusted by the amount of hydrophilic and hydrophobic structural units. Preferred polyether polymers are those with high hydrophilicity, containing an HLB value in the range of 9 to 18.

[0114] As the polyether polymer, it is preferable to use a polyether polymer with high hydrophilicity and a polyether polymer with low hydrophilicity in the range of 1 to 8. The lower the HLB of the polyether polymer, the lower the surface energy of the olefin polymer integrated with the polyether polymer. Therefore, when forming composite particles with the acrylic polymer (B) described later, the impregnation of the composite polymer (a31) constituting the monomer of the acrylic polymer (B) tends to be good. The HLB of the low hydrophilic polyether polymer is preferably 1 to 6, more preferably 1 to 4.

[0115] The polyether polymer preferably has one or more reactive groups that can react with the olefin polymer before being bonded to the olefin polymer.

[0116] Examples of such reactive groups include carboxylic acid groups, dicarboxylic anhydride groups, dicarboxylic anhydride monoester groups, hydroxyl groups, amino groups, epoxy groups, and isocyanate groups. Among the many reactive groups, polyether polymers having at least an amino group are preferred.

[0117] Amino groups are highly reactive with various reactive groups such as carboxylic acid groups, carboxylic anhydride groups, glycidyl groups, and isocyanate groups, thus readily enabling the bonding of olefin polymers and polyether polymers. The amino group can be any of the primary, secondary, or tertiary amino groups, with a primary amino group being preferred.

[0118] Each molecule of the polyether polymer has one or more reactive groups, preferably one. If there are two or more reactive groups, a three-dimensional network structure may be formed and gelled when bonded to olefin polymers. However, even if there are two or more reactive groups, as long as there is only one reactive group with higher reactivity than the others, there can be two or more reactive groups.

[0119] As a polyether polymer having two or more reactive groups, examples include polyether polymers having a hydroxyl group and an amino group that is more reactive than the hydroxyl group.

[0120] Here, "reactivity" refers to the reactivity with reactive groups in olefin polymers.

[0121] The weight-average molecular weight (hereinafter referred to as "Mw") of the polyether polymer is preferably 200 to 200,000, more preferably 300 to 100,000, further preferably 500 to 10,000, and particularly preferably 500 to 3,000. The higher the Mw of the polyether polymer, the lower the surface energy of the composite polymer (a31) tends to be, resulting in better wettability. The lower the Mw of the polyether polymer, the lower the viscosity of the aqueous polymer dispersion of the composite polymer (a31), thus facilitating its preparation.

[0122] The Mw of the polyether polymer is a converted value obtained by GPC determination using a standard curve of polystyrene. GPC determination can be performed using commercially available equipment and known methods with solvents such as tetrahydrofuran (THF).

[0123] The composite polymer (a31) is preferably an olefin polymer with reactive groups, such as an olefin homopolymer (A11) or an olefin copolymer (A21), bonded together with a polyether polymer at a mass ratio of 100:1 to 100:100. This mass ratio is more preferably 100:5 to 100:70, and even more preferably 100:10 to 100:50. Within the range of low polyether polymer proportions, a higher proportion tends to result in smaller particle sizes of the composite polymer (a31). Therefore, when manufacturing composite particles of this composite polymer (a31) and the acrylic polymer (B) described later, the polymerizability of the monomers constituting the acrylic polymer (B) tends to increase. In the range where the proportion of polyether polymer is high, the lower the proportion, the more likely the acid value of the composite polymer (a31) will increase, the polymerizability of the monomers constituting the acrylic polymer (B) will improve, and the adhesion of the coating film to substrates such as olefin substrates will improve.

[0124] When the olefin-based composite polymer (A3) has hydroxyl groups, the hydroxyl value of the olefin-based composite polymer (A3) is preferably 0.01~100 mgKOH / g, more preferably 0.05~80 mgKOH / g, and even more preferably 0.1~50 mgKOH / g. The lower the hydroxyl value, the better the adhesion to the polypropylene substrate. The hydroxyl value is calculated by the following formula (1).

[0125] Hydroxyl value (mgKOH / g) = (f×M1 / Mw / M2×〔KOH〕×1,000) (1)

[0126] (In formula (1), [KOH] is the molecular weight of KOH, f is the number of hydroxyl groups in the hydroxyl-containing monomer, M1 is the mass (g) of the hydroxyl-containing monomer, M2 is the mass (g) of the solid component of the olefin-based composite polymer (A3), and Mw is the molecular weight (weight-average molecular weight) of the hydroxyl-containing monomer.)

[0127] The olefin-based composite polymer (A3) can be a chlorinated olefin obtained by chlorinating an olefin-based polymer. In this case, the degree of chlorination of the chlorinated olefin relative to the total mass of the olefin-based composite polymer (A3) is preferably 40% by mass or less, more preferably 30% by mass or less.

[0128] <Properties of Olefin Polymers (A)>

[0129] The melting point (hereinafter referred to as "Tm") of the olefin polymer (A) is preferably below 125°C, more preferably below 100°C, and even more preferably below 90°C. Furthermore, the Tm of the olefin polymer (A) is preferably above 60°C. The higher the Tm of the olefin polymer (A), the less viscous the polymer becomes. The lower the Tm of the olefin polymer (A), the lower the drying and baking temperature becomes. The lower and upper limits of the Tm of the olefin polymer (A) can be arbitrarily combined, for example, 60~125°C, 60~100°C, or 60~90°C.

[0130] The Tm of olefin polymers (A) can be determined using a differential scanning calorimeter. This determination can be performed, for example, using the "DSCEXSTAR 6000" product from Hitachi High Technologies, Inc.

[0131] The Mw of the olefin polymer (A) in the aqueous polymer dispersion is preferably greater than 200,000. If the Mw of the olefin polymer (A) is greater than 200,000, a coating film that maintains better adhesion to the substrate can be formed even during high-temperature and high-pressure cleaning.

[0132] The Mw of the olefin polymer (A) is more preferably greater than 200,000 and less than 2,000,000. The lower limit of the Mw of the olefin polymer (A) is further preferably 230,000, and particularly preferably 250,000. The upper limit of the Mw of the olefin polymer (A) is further preferably 1,000,000, and particularly preferably 500,000. If the Mw of the olefin polymer (A) is within the above range, the adhesion to the substrate during high-temperature and high-pressure cleaning is further improved.

[0133] The Mw of the olefin polymer (A) in the aqueous polymer dispersion is a value converted from the standard curve of polystyrene by GPC determination. GPC can be performed using commercially available equipment and known methods with solvents such as o-dichlorobenzene and tetrahydrofuran.

[0134] The complex viscosity of the olefin polymer (A) at 200°C and 0.1 Hz is preferably 1,500 Pa·s or more, more preferably greater than 1,500 Pa·s, further preferably 2,000 Pa·s or more, particularly preferably 3,000 Pa·s or more, and most preferably 4,500 Pa·s or more. The complex viscosity of the olefin polymer (A) at 200°C and 0.1 Hz is preferably 30,000 Pa·s or less, more preferably 15,000 Pa·s or less, and further preferably 10,000 Pa·s or less. The upper limit of the complex viscosity of the olefin polymer (A) at 200°C and 0.1 Hz can be, for example, 100,000 Pa·s. The lower and upper limits of the complex viscosity of the olefin polymer (A) at 200°C and 0.1 Hz can be arbitrarily combined. For example, it can be 1,500~100,000 Pa·s, greater than 1,500 Pa·s and less than 30,000 Pa·s, 2,000~15,000 Pa·s, 3,000~10,000 Pa·s, or 4,500~10,000 Pa·s.

[0135] Complex viscosity was measured using a rheometer at 200°C and 0.1 Hz after the aqueous polymer dispersion containing olefin polymer (A) was vacuum dried at 40°C for 12 hours.

[0136] The melt flow rate (hereinafter referred to as "MFR") of the olefin polymer (A) is preferably less than 20 g / 10 min at 230°C and a load of 2.16 kg, more preferably less than 10 g / 10 min, and even more preferably less than 8 g / 10 min. The lower limit of the MFR of the olefin polymer (A) is typically around 0.1 g / 10 min. The lower and upper limits of the MFR of the olefin polymer (A) can be arbitrarily combined, for example, it can be more than 0.1 g / 10 min and less than 20 g / 10 min, it can be 0.1 to 10 g / 10 min, or it can be 0.1 to 8 g / 10 min.

[0137] The MFR of the olefin polymer (A) was determined according to the method of ASTM D1238.

[0138] <Method for manufacturing olefin polymer (A)>

[0139] Methods for manufacturing olefin polymers (A) include, for example, free radical polymerization, cationic polymerization, anionic polymerization, and coordination polymerization of olefins. Furthermore, these polymerizations can also be living polymerizations.

[0140] The polymerization method can be any of the following: solution polymerization, slurry polymerization, bulk polymerization, gas-phase polymerization, etc.

[0141] In solution polymerization and slurry polymerization, solvents can include, for example, aromatic hydrocarbons such as toluene and xylene, aliphatic hydrocarbons such as hexane, heptane, and octane, alicyclic hydrocarbons such as cyclohexane and methylcyclohexane, halogenated hydrocarbons, esters, ketones, and ethers. Among these solvents, aromatic hydrocarbons, aliphatic hydrocarbons, and alicyclic hydrocarbons are preferred, and toluene, xylene, heptane, and cyclohexane are more preferred. One solvent can be used alone, or two or more solvents can be used in combination.

[0142] As an initiator used in free radical polymerization, benzoyl peroxide or tert-butylperoxyisopropyl monocarbonate are preferred, for example.

[0143] Free radical polymerization initiators can be used alone or in combination of two or more.

[0144] Examples of catalysts used in coordination polymerization include Ziegler-Natta catalysts and unit point catalysts.

[0145] Typically, single-site catalysts can have their molecular weight and stereoregularity distributions sharpened through ligand design. Examples of single-site catalysts include metallocene catalysts and Brookhart-type catalysts.

[0146] Metallocene catalysts, for example, include C1-symmetric, C2-symmetric, C2V-symmetric, and CS-symmetric types. An appropriate selection from these can be made based on the stereoregularity of the desired olefin.

[0147] <<Method for Manufacturing Olefin Polymers with Reactive Groups>>

[0148] Olefin polymers having reactive groups can be manufactured by, for example, by grafting a free radical polymerizable monomer having reactive groups onto an olefin polymer. Other methods include heating and stirring an olefin polymer and a free radical polymerizable monomer having reactive groups in a solution, melting and stirring the mixture in a solvent-free environment, or heating and mixing the mixture using an extruder. Among these, graft polymerization is preferred as a method for manufacturing olefin polymers having reactive groups.

[0149] As a free radical polymerizable monomer with reactive groups, a free radical polymerizable monomer having a carboxyl group or its anhydride structure is preferred. Examples include (meth)acrylic acid, fumaric acid, maleic acid and its anhydride, itaconic acid and its anhydride, and crotonic acid.

[0150] Free radical polymerizable monomers with reactive groups can be used alone or in combination of two or more. Furthermore, olefin polymers used in graft polymerization can be used alone or in combination of two or more.

[0151] As a free radical polymerization initiator used in graft polymerization, for example, a suitable selection and use can be made from known free radical polymerization initiators such as organic peroxides and azonitrs.

[0152] Examples of organic peroxides include, for example, ketal peroxides such as di(tert-butylperoxy)cyclohexane, hydroperoxides such as cumene hydroperoxide, dialkyl peroxides such as di-tert-butylperoxide, diacyl peroxides such as benzoyl peroxide, and peroxide esters such as tert-butylperoxyisopropyl monocarbonate. Organic peroxides can be used alone or in combination with two or more.

[0153] Examples of azonitrile include azobisbutyronitrile and azobisisopropionitrile. Azonitrile can be used alone or in combination with two or more types.

[0154] The ratio of free radical polymerization initiator to grafted free radical polymerizable monomer is preferably in the range of 1:100 to 2:1 (molar ratio), and more preferably in the range of 1:20 to 1:1.

[0155] The reaction temperature for graft polymerization is preferably 50°C or higher, more preferably 50-200°C, and even more preferably 80-200°C. The reaction time for graft polymerization is preferably 2-20 hours.

[0156] As a solvent for manufacturing in solution, the same solvent as that described in the manufacturing method of solution polymerization of olefin polymer (A) can be used.

[0157] <<Method for manufacturing composite polymer (a31)>>

[0158] In a composite polymer (a31) formed by integrating at least one polymer selected from the group consisting of olefin homopolymers (A1) and olefin copolymers (A2) with a hydrophilic polymer such as a polyether polymer, when the hydrophilic polymer is a polyether polymer, the polyether polymer can be integrated with the olefin polymer in a bonded state, for example, by the following methods.

[0159] • A method for ring-opening polymerization of cyclic alkylene oxides in the presence of olefin polymers with reactive groups, such as olefin homopolymers (A11) and olefin copolymers (A21).

[0160] A method for reacting reactive groups of polyether polyols or polyether amines obtained by ring-opening polymerization with reactive groups of olefin polymers having reactive groups.

[0161] (Acrylic polymer (B))

[0162] The acrylic polymer (B) is a polymer having structural units derived from at least one (meth)acrylic monomer (hereinafter referred to as "monomer (b1)"). Examples of monomer (b1) include (meth)acrylic acid and (meth)acrylate. That is, the acrylic polymer (B) is preferably having at least one structural unit derived from (meth)acrylic acid and a structural unit derived from (meth)acrylate.

[0163] In addition to the structural units derived from monomer (b1), acrylic polymer (B) may, as needed, further have structural units derived from olefinic unsaturated monomers other than monomer (b1) (hereinafter referred to as "monomer (b2)").

[0164] Acrylic polymer (B) is a homopolymer or copolymer obtained by polymerizing monomeric component (b) containing monomer (b1). Acrylic polymer (B) is preferably a copolymer.

[0165] Monomer component (b) contains at least one monomer (b1). In addition to monomer (b1), monomer component (b) may further contain monomer (b2) as needed.

[0166] The content and composition of the structural units of each monomer from the acrylic polymer (B) can be determined by NMR. In addition, the content of each monomer relative to the total monomer component (b) can be regarded as the content of the structural units from that monomer in the acrylic polymer (B).

[0167] Examples of monomers (b1) include (meth)acrylic acid and (meth)acrylates. Among these, (meth)acrylates are preferred (hereinafter referred to as "monomer (b11)").

[0168] Examples of monomers (b11) include alkyl (meth)acrylates with branched structures and alkyl (meth)acrylates with straight-chain structures. Among these, alkyl (meth)acrylates with branched structures are preferred.

[0169] Examples of alkyl (meth)acrylates with branched chain structures include, for example, 2-ethylhexyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, isoamyl (meth)acrylate, 1-methylheptyl (meth)acrylate, isononyl (meth)acrylate, isodecanyl (meth)acrylate, isothiazines (meth)acrylate, isotridecyl (meth)acrylate, isomyristyl (meth)acrylate, isostearyl (meth)acrylate, and isobornyl (meth)acrylate.

[0170] Alkyl (meth)acrylates with branched structures can be used alone or in combination with two or more. Among the many alkyl (meth)acrylates with branched structures, isobornyl (meth)acrylate, isobutyl (meth)acrylate, and tert-butyl (meth)acrylate are preferred, more preferably isobornyl (meth)acrylate, and even more preferably isobornyl methacrylate. That is, the acrylic polymer (B) preferably contains at least a structural unit derived from isobornyl methacrylate.

[0171] Relative to the total mass of all structural units contained in the acrylic polymer (B), the content of structural units derived from isobornyl methacrylate is preferably 1-100% by mass, more preferably 10-95% by mass, further preferably 20-90% by mass, particularly preferably 30-80% by mass, and most preferably 30-60% by mass. If the content of structural units derived from isobornyl methacrylate is above the lower limit mentioned above, the adhesion of the coating to the substrate is further improved, and the adhesion to the substrate can be better maintained during high-temperature and high-pressure cleaning. If the content of structural units derived from isobornyl methacrylate is below the upper limit mentioned above, the adhesion of the coating to the substrate is further improved, and the adhesion can be better maintained during high-temperature and high-pressure cleaning.

[0172] Examples of alkyl (meth)acrylates having a straight-chain structure include, for example, methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, n-pentyl (meth)acrylate, n-hexyl (meth)acrylate, cyclohexyl (meth)acrylate, n-heptyl (meth)acrylate, n-octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, nonyl (meth)acrylate, lauryl (meth)acrylate, n-tetrazyl (meth)acrylate, n-stearyl (meth)acrylate, and behenyl (meth)acrylate.

[0173] Alkyl (meth)acrylates with a straight-chain structure can be used alone or in combination with two or more. Among the many alkyl (meth)acrylates with a straight-chain structure, methyl methacrylate, ethyl methacrylate, and n-butyl methacrylate are preferred because they can form a coating that maintains better adhesion to the substrate even during high-temperature and high-pressure cleaning.

[0174] Monomer (b11) may be a monomer with a functional group. That is, monomer component (b) may contain monomers with functional groups.

[0175] Examples of monomers with functional groups include hydroxyl-containing monomers, carboxyl-containing monomers, monomers containing nitrogen-containing functional groups, monomers containing acetoacetyl groups, monomers containing isocyanate groups, and monomers containing glycidyl groups.

[0176] Monomers with functional groups can be used alone or in combination of two or more. Among them, hydroxyl-containing monomers are preferred.

[0177] Examples of hydroxyl-containing monomers include, for example, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 3-hydroxypropyl methacrylate, 2-hydroxybutyl methacrylate, 4-hydroxybutyl methacrylate, 5-hydroxypentyl methacrylate, 6-hydroxyhexyl methacrylate, and 8-hydroxyoctyl methacrylate.

[0178] Caprolactone-modified monomers such as 2-hydroxyethyl methacrylate;

[0179] Oxidized alkenyl-modified monomers such as diethylene glycol (meth)acrylate, polyethylene glycol (meth)acrylate, and polypropylene glycol (meth)acrylate;

[0180] 2-Acryloyloxyethyl-2-hydroxyethyl phthalic acid and other monomers containing primary hydroxyl groups;

[0181] 2-Hydroxypropyl (meth)acrylate, 2-Hydroxybutyl (meth)acrylate, 3-chloro-2-hydroxypropyl (meth)acrylate, and other monomers containing secondary hydroxyl groups;

[0182] Monomers containing tertiary hydroxyl groups, such as 2,2-dimethyl-2-hydroxyethyl (meth)acrylate.

[0183] The hydroxyl-containing monomer can be used alone or in combination with two or more. Among the many hydroxyl-containing monomers, based on storage stability and adhesion, 2-hydroxyethyl methacrylate, 4-hydroxybutyl methacrylate, and 2-hydroxypropyl methacrylate are preferred, and 2-hydroxyethyl methacrylate and 4-hydroxybutyl methacrylate are more preferred.

[0184] The lower the proportion of di(meth)acrylate contained as an impurity in the hydroxyl-containing monomer, the better. For example, the proportion of di(meth)acrylate relative to the total mass of the hydroxyl-containing monomer is preferably 0.5% by mass or less, more preferably 0.2% by mass or less, further preferably 0.1% by mass or less, and particularly preferably 0% by mass.

[0185] Examples of carboxyl-containing monomers include, for example, carboxyethyl (meth)acrylate, carboxypropyl (meth)acrylate, carboxybutyl (meth)acrylate, ω-carboxylated polycaprolactone mono(meth)acrylate, 2-(meth)acryloyloxyethyl hexahydrophthalic acid, 2-(meth)acryloyloxypropyl hexahydrophthalic acid, 2-(meth)acryloyloxyethyl phthalic acid, 2-(meth)acryloyloxypropyl phthalic acid, 2-(meth)acryloyloxyethyl maleate, 2-(meth)acryloyloxypropyl maleate, 2-(meth)acryloyloxyethyl succinate, 2-(meth)acryloyloxypropyl succinate, etc.

[0186] Carboxyl-containing monomers can be used alone or in combination with two or more.

[0187] Examples of monomers containing functional groups with nitrogen atoms include amino monomers and amide monomers.

[0188] Examples of amino-containing monomers include aminomethyl methacrylate, aminoethyl methacrylate, and other (meth)acrylates containing primary amino groups.

[0189] (Meth)acrylates containing secondary amino groups, such as tert-butylaminoethyl methacrylate and tert-butylaminopropyl methacrylate.

[0190] Ethylaminoethyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, dimethylaminoethyl methacrylate, dimethylaminopropyl methacrylate, diethylaminopropyl methacrylate, dimethylaminopropylacrylamide, and other tertiary amino-containing (meth)acrylates.

[0191] Amino monomers can be used alone or in combination with two or more.

[0192] Examples of amide-containing monomers include, for example, (meth)acrylamide;

[0193] N-methyl (meth)acrylamide, N-ethyl (meth)acrylamide, N-propyl (meth)acrylamide, N-n-butyl (meth)acrylamide, diacetone (meth)acrylamide, N,N'-methylenebis(meth)acrylamide and other N-alkyl (meth)acrylamides;

[0194] N,N-Dimethyl (meth)acrylamide, N,N-Diethyl (meth)acrylamide, N,N-Dipropyl (meth)acrylamide, N,N-Ethylmethylacrylamide, N,N-Diallyl (meth)acrylamide, and other N,N-dialkyl (meth)acrylamides;

[0195] N-hydroxymethyl (meth)acrylamide, N-hydroxyethyl (meth)acrylamide, and other hydroxyalkyl (meth)acrylamides;

[0196] N-methoxymethyl (meth)acrylamide, N-(n-butoxymethyl) (meth)acrylamide, and other alkoxyalkyl (meth)acrylamides;

[0197] Vinylpyrrolidone.

[0198] Amid-containing monomers can be used alone or in combination with two or more.

[0199] Examples of monomers containing an acetyl group include (meth)acrylate-2-(acetylacetoxy)ethyl ester and allyl acetoacetate.

[0200] Examples of isocyanate-containing monomers include, for example, 2-acryloyloxyethyl isocyanate, 2-methacryloyloxyethyl isocyanate, and alkyl oxide adducts of these monomers.

[0201] Examples of monomers containing glycidyl groups include glycidyl (meth)acrylate, allyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate.

[0202] These monomers can be used individually or in combination of two or more.

[0203] In addition to the above, examples of monomers (b11) include, for example, phenyl methacrylate, benzyl methacrylate, phenoxyethyl methacrylate, diethylene glycol methacrylate, phenoxy polyethylene glycol (meth)acrylate, phenoxy polyethylene glycol-polypropylene glycol-(meth)acrylate, o-phenylphenoxyethyl (meth)acrylate, nonylphenol ethylene oxide adduct (meth)acrylate, etc., which contain aromatic rings; alicyclic monomers such as cyclohexyloxyalkyl (meth)acrylate; 2-methoxyethyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, 3-methoxypropyl (meth)acrylate, 3-methoxybutyl (meth)acrylate, 2-butoxyethyl (meth)acrylate, etc. Monomers containing ether chains, such as acrylates, 2-butoxydiethylene glycol (meth)acrylates, methoxydiethylene glycol (meth)acrylates, methoxytriethylene glycol (meth)acrylates, ethoxydiethylene glycol (meth)acrylates, methoxydipropylene glycol (meth)acrylates, methoxypolyethylene glycol (meth)acrylates, octyloxypolyethylene glycol-polypropylene glycol mono(meth)acrylates, lauryloxypolyethylene glycol mono(meth)acrylates, stearyloxypolyethylene glycol mono(meth)acrylates, etc.; monomers containing benzophenone, such as 4-(meth)acryloyloxybenzophenone; and monomers containing fluorine atoms, such as trifluoromethyl (meth)acrylates, 2-trifluoroethyl (meth)acrylates, 2-perfluoroethyl (meth)acrylates, etc.

[0204] These monomers can be used individually or in combination of two or more.

[0205] In addition, as a monomer having two or more olefinic unsaturated groups, it can be used in combination with ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, etc.

[0206] Monomers with two or more olefinic unsaturated groups can be used alone or in combination with two or more.

[0207] Monomer (b2) is any monomer other than monomer (b1). There are no particular limitations as long as it can copolymerize with monomer (b1). Examples include acrylonitrile, methacrylonitrile; aromatic compounds such as styrene and α-methylstyrene; carboxyl-containing monomers such as crotonic acid, maleic acid, maleic anhydride, fumaric acid, citraconic acid, penteneic acid, itaconic acid, N-glycolic acid, and cinnamic acid; vinyl acetate, vinyl neodecanoate, vinyl propionate, vinyl stearate, vinyl chloride, vinylidene chloride, alkyl vinyl ether, vinyltoluene, vinylpyridine, vinylpyrrolidone, dialkyl itaconic acid, dialkyl fumarate, acryloyl chloride, methyl vinyl ketone, N-acrylamidomethyltrimethylammonium chloride, allyltrimethylammonium chloride, and dimethylallyl vinyl ketone.

[0208] Monomer (b2) can be used alone or in combination with two or more. Among the many monomers (b2), styrene is preferred based on its storage stability, adhesion, and high-temperature and high-pressure cleaning properties.

[0209] <Properties of Acrylic Polymer (B)>

[0210] The glass transition temperature (hereinafter referred to as "Tg") of the acrylic polymer (B) is 105°C or higher, preferably 110°C or higher, more preferably 120°C or higher, and particularly preferably 123°C or higher. Furthermore, the Tg of the acrylic polymer (B) is preferably 200°C or lower, more preferably 190°C or lower, 170°C or lower, and particularly preferably 150°C or lower. If the Tg of the acrylic polymer (B) is above or below the aforementioned lower limit, a coating film that maintains adhesion to the substrate can be formed even during high-temperature and high-pressure cleaning. If the Tg of the acrylic polymer (B) is below the aforementioned upper limit, film-forming properties become good, and when the aqueous polymer dispersion is used as a coating, the amount of film-forming aid used in formulating the coating can be reduced. The lower and upper limits of the acrylic polymer (B) can be arbitrarily combined; for example, it can be 105~200°C, 110~190°C, 120~170°C, or 123~150°C.

[0211] The Tg of the acrylic polymer (B) is calculated using the Fox formula represented by equation (2) below. The Tg of the acrylic polymer (B) can be controlled, for example, by the selection of monomers and their composition ratios.

[0212] 1 / (273+Tg)=Σ(Wi / (273+Tgi)) Formula (2)

[0213] (In equation (2), Wi is the mass fraction of monomer i, and Tgi is the glass transition temperature (°C) of the homopolymer of monomer i.

[0214] Here, the glass transition temperature of the homopolymers of each monomer is determined by the following method.

[0215] <method>

[0216] Add 5 mL of the sample to a 20 mL ampoule, add 0.1% (w / w) of azobisisobutyronitrile as a polymerization initiator, heat and seal, then heat to 65–130 °C and polymerize for 5–40 hours. Remove the resulting polymer from the ampoule and crush it. Take 1.5 g and add it to a 100 mL beaker, add 50 mL of methanol, and stir overnight. Then filter the methanol, add another 50 mL of methanol, stir and filter, repeating this process three times. Dry at 100 °C for 2 hours to obtain the sample for glass transition temperature determination.

[0217] Using a differential scanning calorimeter (DSC) (PERKIN-ELMER, differential scanning calorimetry apparatus), the glass transition temperature measurement sample obtained above was heated to 200°C at a heating rate of 10°C / min, held for 5 minutes to melt it, then cooled to 0°C at a heating rate of 10°C / min, heated again at a heating rate of 10°C / min, held for 5 minutes, and then cooled again at a heating rate of 10°C / min to determine the glass transition temperature.

[0218] Furthermore, the glass transition temperatures of the homopolymers of the main monomers are as follows.

[0219] Methyl methacrylate: 105℃, Isobutyl methacrylate: 48℃, Tert-butyl acrylate: 41℃, n-Hexyl methacrylate: -32.3℃, 2-Ethylhexyl acrylate: -55℃, Benzyl methacrylate: 54℃, Isobornyl methacrylate: 180℃, Glycidyl methacrylate: 46℃, 2-Hydroxybutyl acrylate: -39.4℃, 2-Hydroxybutyl methacrylate: 47℃, 4-Hydroxybutyl acrylate: -85.5℃, 4-Hydroxybutyl methacrylate: 20.3℃.

[0220] (Aqueous medium)

[0221] Aqueous media are used to disperse olefin polymers (A) and acrylic polymers (B).

[0222] As an aqueous medium, it can be used to extract water.

[0223] Furthermore, as an aqueous polymer dispersion, it can contain organic solvents in addition to water. That is, the aqueous medium can be a mixture of water and organic solvents.

[0224] There is no particular limitation on water; for example, tap water, deionized water, ion-exchanged water, distilled water, and purified water can be cited.

[0225] Water can be used alone or in combination with two or more types.

[0226] The water content relative to the total mass of the aqueous medium is preferably 50% by mass or more, more preferably 80% by mass or more, and even more preferably 90% by mass or more. The upper limit can be 100% by mass, 98% by mass, or 95% by mass. The lower and upper limits of the water content can be arbitrarily combined; for example, it can be 50-100% by mass, 80-98% by mass, or 90-95% by mass.

[0227] As an organic solvent, any organic solvent commonly used in water-based coatings can be used. Examples include aliphatic alcohols with 5 to 14 carbon atoms (linear, branched, or cyclic); alcohols containing aromatic groups; and those with the general formula HO-(CH2CHXO). p -R 1 (R) 1 It is a straight-chain or branched alkyl group having 1 to 10 carbon atoms, where X is a hydrogen atom or a methyl group, and p is an integer less than 5. It represents a monoether such as (poly)ethylene glycol or (poly)propylene glycol; general formula R 2 COO-(CH2CHXO) q -R 3 (R) 2 R 3 It is a straight-chain or branched alkyl group with 1 to 10 carbon atoms, where X is a hydrogen atom or a methyl group, and q is an integer less than 5. It represents (poly)ethylene glycol ether esters or (poly)propylene glycol ether esters; aromatic organic solvents such as toluene and xylene; monoisobutyrate of 2,2,4-trimethyl-1,3-pentanediol, diisobutyrate of 2,2,4-trimethyl-1,3-pentanediol, 3-methoxybutanol, 3-methoxybutanol acetate, 3-methyl-3-methoxybutanol, and 3-methyl-3-methoxybutanol acetate.

[0228] Organic solvents may be used alone or in combination of two or more. Among the many organic solvents, linear, branched or cyclic aliphatic alcohols with 5 to 14 carbon atoms are preferred, alcohol solvents with 7 to 14 carbon atoms are more preferred, and alcohol solvents selected from at least one of the following groups: 1-octanol, 2-octanol, 2-ethyl-1-hexanol, ethylene glycol mono(2-ethylhexyl) ether, diethylene glycol mono-n-butyl ether, propylene glycol mono-n-butyl ether, dipropylene glycol mono-n-methyl ether, and dipropylene glycol mono-n-butyl ether.

[0229] The content of organic solvent relative to the total mass of the aqueous medium is preferably 50% by mass or less, more preferably 20% by mass or less, and even more preferably 10% by mass or less. The lower limit can be 0% by mass, 2% by mass, or 5% by mass. The lower and upper limits of the content of the organic solvent can be combined arbitrarily, for example, 0 to 50% by mass, 2 to 20% by mass, or 5 to 10% by mass.

[0230] (Any ingredient)

[0231] As any component, examples include various pigments, polymer beads, defoamers, pigment dispersants, leveling agents, anti-sagging agents, curing catalysts, matting agents, ultraviolet absorbers, light stabilizers, antioxidants, heat resistance improvers, slip agents, preservatives, plasticizers, thickeners, wetting agents, solvents other than aqueous media, and various other additives.

[0232] Additives can be used alone or in combination with two or more.

[0233] In addition, the aqueous polymer dispersion, as an arbitrary component, may further contain, for example, polymer particles, water-soluble polymers, viscosity modifiers, amino polymers, polyisocyanate compounds, blocked polyisocyanate compounds, melamine polymers, urea polymers, carboxyl-containing compounds, carboxyl-containing polymers, epoxy-containing polymers, epoxy-containing compounds, carbodiimide-containing compounds, and other curing agents.

[0234] Other polymer particles include, for example, dispersed particles composed of polymers other than polyester polymers, polyurethane polymers, acrylic polymers (B), acrylic silicone polymers, silicone polymers, fluoropolymers, epoxy polymers, alkyd polymers, etc.

[0235] In addition, aqueous polymer dispersions may contain surfactants as any component in order to improve storage stability.

[0236] As surfactants, various anionic, cationic, or nonionic surfactants, as well as polymeric surfactants, can be cited. So-called reactive surfactants, which have olefinically unsaturated bonds, can also be used as surfactants.

[0237] A single surfactant may be used alone, or two or more may be used in combination. Among the many surfactants available, anionic surfactants are preferred from the viewpoint of improving the storage stability of the resulting aqueous polymer dispersion. There are no particular limitations on the type of anionic surfactant; for example, ADEKA Reasoap SR, a reactive surfactant manufactured by ADEKA Corporation, and Neocol SW-C, a non-reactive surfactant, may be used.

[0238] Relative to a total of 100 parts by mass of the olefin polymer (A) and the acrylic polymer (B), the surfactant content is preferably 2 parts by mass or less, more preferably 1 part by mass or less, and can be 0 parts by mass. By keeping the surfactant content below the above-mentioned upper limit, the stability of the coating formulation can be maintained without sacrificing water resistance.

[0239] (Example of embodiments of aqueous polymer dispersions)

[0240] In an aqueous polymer dispersion, olefin polymer (A) and acrylic polymer (B) can be dispersed separately in an aqueous medium, or they can be dispersed as composite particles of olefin polymer (A) and acrylic polymer (B) in an aqueous medium. That is, olefin polymer (A) and acrylic polymer (B) can form composite particles. From the viewpoint of the stability of the aqueous polymer dispersion, the aqueous polymer dispersion is preferably a composite particle containing olefin polymer (A) and acrylic polymer (B).

[0241] The method for manufacturing composite particles is described below.

[0242] <Proportion>

[0243] The preferred mass ratio (A:B) of the olefin polymer (A) and acrylic polymer (B) in the aqueous polymer dispersion is 25:75 to 99:1, more preferably 30:70 to 99:1, 40:60 to 98:2, 50:50 to 95:5, further preferably 70:30 to 90:10, and particularly preferably 20:80 to 60:40. A higher proportion of acrylic polymer (B) relative to olefin polymer (A) tends to improve the storage stability of the aqueous polymer dispersion. A lower proportion of acrylic polymer (B) relative to olefin polymer (A) tends to further improve the adhesion of the coating film to the substrate.

[0244] When the olefin polymer (A) has a hydroxyl group as a reactive group, the content of the acrylic polymer (B) relative to 100 parts by mass of the olefin polymer (A) is preferably 0.01 to 50 parts by mass, more preferably 0.05 to 40 parts by mass, and even more preferably 0.1 to 30 parts by mass. If the content of the acrylic polymer (B) is above the lower limit mentioned above, the water resistance of the coating film tends to be improved. If the content of the acrylic polymer (B) is below the upper limit mentioned above, the adhesion of the coating film to substrates such as olefin substrates tends to be improved.

[0245] When the olefin polymer (A) has an epoxy group as a reactive group, the content of the acrylic polymer (B) relative to 100 parts by mass of the olefin polymer (A) is preferably 0.01 to 50 parts by mass, more preferably 0.05 to 40 parts by mass, and even more preferably 0.1 to 30 parts by mass. If the content of the acrylic polymer (B) is above the lower limit mentioned above, the water resistance of the coating film tends to be improved. If the content of the acrylic polymer (B) is below the upper limit mentioned above, the adhesion of the coating film to substrates such as olefin substrates tends to be improved.

[0246] Relative to the total mass of the aqueous polymer dispersion, the total content of olefin polymer (A) and acrylic polymer (B) is preferably 5-80% by mass, more preferably 10-70% by mass, and even more preferably 20-60% by mass. If the total content of olefin polymer (A) and acrylic polymer (B) is above the lower limit mentioned above, a coating film of sufficient thickness can be easily formed by a single coating application. If the total content of olefin polymer (A) and acrylic polymer (B) is below the upper limit mentioned above, the olefin polymer (A) and acrylic polymer (B) can be sufficiently dispersed in the aqueous medium.

[0247] <Average Particle Size>

[0248] The average particle size of the aqueous polymer dispersion is preferably below 500 nm, more preferably below 300 nm, and even more preferably below 200 nm. If the average particle size of the aqueous polymer dispersion is below the aforementioned upper limit, it tends to improve the film-forming properties of the coating and further enhance its adhesion to the substrate. The lower limit of the average particle size of the aqueous polymer dispersion is not particularly limited; for example, it can be around 1 nm. The lower and upper limits of the average particle size of the aqueous polymer dispersion can be arbitrarily combined; for example, it can be 1~500 nm, 1~300 nm, or 1~200 nm.

[0249] The average particle size of an aqueous polymer dispersion is the average particle size of all components in the aqueous polymer dispersion other than the aqueous medium.

[0250] The average particle size of the aqueous polymer dispersion was determined using a device that measures particle size distribution by dynamic light scattering, and the harmonic average particle size (also known as the cumulative diameter) was calculated based on the scattered light intensity standard through cumulant analysis. This determination, for example, can be performed using the Otsuka Electronics Co., Ltd. high-concentration system particle size analyzer "FPAR-1000" and its accompanying software.

[0251] (Method for manufacturing aqueous polymer dispersions)

[0252] Aqueous polymer dispersions can be obtained by stirring and mixing olefin polymers (A) and acrylic polymers (B) with any other desired components in an aqueous medium.

[0253] Olefin polymer (A) and acrylic polymer (B) can be pre-dispersed in an aqueous medium. That is, an aqueous polymer dispersion can be prepared by mixing an aqueous dispersion (α) of olefin polymer (A) and an aqueous dispersion (β) of acrylic polymer (B).

[0254] As a method for dispersing an olefin polymer (A) in an aqueous medium to obtain an aqueous dispersion (α), an example method is to add an organic solvent to the olefin polymer (A), heat appropriately to dissolve it, and then add water. This method has the advantage of easily producing an aqueous dispersion (α) with a small particle size. The temperature at which the organic solvent is dissolved and the water is added is preferably 30 to 150°C, more preferably 50 to 100°C. The organic solvent can be removed by distillation after adding water.

[0255] As for water and organic solvents, examples already mentioned in the description of aqueous media can be cited.

[0256] The apparatus used in the method of adding an organic solvent to an olefin polymer (A), dissolving it by appropriate heating, and then adding water can be, for example, a reactor with a stirring device, a single-screw or twin-screw mixer, etc. The stirring speed varies depending on the choice of apparatus, but is generally in the range of 10 to 1000 rpm. If the stirring speed is above the lower limit of the above-mentioned value range, the particle size of the aqueous dispersion (α) is less likely to become too large.

[0257] Aqueous dispersions (β) of acrylic polymers (B) can be obtained by the same method as aqueous dispersions (α).

[0258] Furthermore, as a method for manufacturing an aqueous polymer dispersion containing composite particles of olefin polymer (A) and acrylic polymer (B), the following methods can be cited as examples.

[0259] • A method for polymerizing monomer components (b) in an aqueous dispersion (α) of an olefin homopolymer (A1), an olefin copolymer (A2), or a composite polymer (a31) to integrate an acrylic polymer (B).

[0260] • A method of dispersing an olefin homopolymer (A1), an olefin copolymer (A2), or a composite polymer (a31) and a monomer component (b) in an aqueous medium and then polymerizing the monomer component (b) to achieve integration.

[0261] From the perspective of the polymerizability of monomeric component (b), the former method is preferred.

[0262] The polymerization of monomer component (b) can be a one-step addition polymerization, a dropwise addition polymerization, or a combination thereof, without impairing the effects of the present invention. From the viewpoint of polymerization stability and adhesion to substrates such as polyolefin substrates, one-step addition polymerization is preferred.

[0263] Here, "one-time addition polymerization" refers to a method in which all monomers are added at once for polymerization. In addition, "droplet addition polymerization" refers to a method in which monomers are added drop by drop for polymerization.

[0264] One-step polymerization can be carried out by mixing olefin polymers (A) and monomer components (b) and then performing free radical polymerization using an initiator.

[0265] Droplet polymerization, for example, can be carried out by adding monomer component (b) dropwise to an olefin polymer (A) in the presence of an initiator.

[0266] Of the above, it is preferable to polymerize the monomer component (b) in an aqueous dispersion (α) in a single feeding to produce an aqueous polymer dispersion containing composite particles of an olefin polymer (A) and an acrylic polymer (B). In particular, it is more preferable to bulk polymerize the monomer component (b) in an aqueous dispersion (α) of a composite polymer (a31) to produce an aqueous polymer dispersion containing composite particles of a composite polymer (a31) and an acrylic polymer (B).

[0267] For the initiator used in the polymerization of monomer component (b), initiators that are generally applicable to free radical polymerization can be used. Examples include persulfates such as potassium persulfate, sodium persulfate, and ammonium persulfate; oil-soluble azo compounds such as azobisisobutyronitrile, 2,2'-azobis(2-methylbutyronitrile), 2,2'-azobis(2,4-dimethylpentanitrile), 2,2'-azobis(4-methoxy-2,4-dimethylpentanitrile), and 2-phenylazo-4-methoxy-2,4-dimethylpentanitrile; and 2,2'-azobis{2-methyl-N-[1,1-bis(hydroxymethyl)-2-hydroxyethyl]propionamide}, 2,2'-azobis{2-methyl-N-[2-(1-hydroxyethyl)]propionamide}, and 2,2'-azobis{2-methyl-N-[2-(1-hydroxyethyl)]propionamide}. [Butyl]propamide, 2,2'-azobis[2-(5-methyl-2-imidazolin-2-yl)propane] and its salts; 2,2'-azobis[2-(2-imidazolin-2-yl)propane] and its salts; 2,2'-azobis{2-[1-(2-hydroxyethyl)-2-imidazolin-2-yl]propane} and its salts; 2,2'-azobis(2-methylpropanediamine) and its salts; 2,2'-azobis[N-(2-carboxyethyl)-2-methylpropanediamine] and other water-soluble azo compounds; benzoyl peroxide, cumene hydroperoxide, tert-butyl hydroperoxide, tert-butyl peroxide-2-ethylhexanoate, tert-butyl peroxide and other organic peroxides.

[0268] Initiators can be used alone or in combination with two or more.

[0269] When monomer component (b) is polymerized, a reducing agent can be further added to the reaction system to carry out a redox polymerization reaction. Preferred free radical polymerization methods include methods that use water-soluble initiators for polymerization, and methods that use organic peroxides as initiators and ferrous sulfate or isoascorbic acid as reducing agents in redox reactions for polymerization.

[0270] Furthermore, when polymerizing monomer component (b), a molecular weight regulator can be used. Examples of known chain transfer agents include n-dodecyl mercaptan, tert-dodecyl mercaptan, and α-methylstyrene dimer.

[0271] From the viewpoint of polymerization rate, the polymerization temperature of monomer component (b) is preferably 50°C or higher. At this point, a combination of reducing agents such as sodium bisulfite, ferrous sulfate, isoascorbic acid salt, and Rongalit, along with a water-soluble free radical polymerization catalyst, is preferably used as the initiator. There is no particular upper limit to the polymerization temperature of monomer component (b); for example, it can be below 95°C.

[0272] The polymerization time of monomer component (b) is preferably 30 minutes or more. If the time is less than 30 minutes, monomer component (b) cannot polymerize sufficiently, resulting in a poor polymerization rate. Furthermore, the polymerization time is preferably 3 hours or less. If the time exceeds 3 hours, a large number of cullets will be generated during polymerization, leading to decreased manufacturing stability.

[0273] After the polymerization reaction is complete, when cooling and removing the aqueous polymer dispersion, filtration is preferable to prevent the introduction of foreign matter or fragments. Known methods can be used for filtration, such as nylon mesh, bag filters, filter paper, and metal mesh.

[0274] (Effects)

[0275] The aqueous polymer dispersion of this embodiment described above contains the olefin polymer (A) and an acrylic polymer (B) with a glass transition temperature greater than a specific value, which can form a coating that maintains adhesion to the substrate even after high-temperature and high-pressure cleaning.

[0276] (Adhesion during high-temperature and high-pressure cleaning)

[0277] In terms of adhesion during high-temperature and high-pressure cleaning, as measured by the following method, the spray distance d of the aqueous polymer dispersion of this embodiment is 12 cm or less, more preferably 11 cm or less.

[0278] Aqueous polymer dispersions were coated onto an olefin substrate (propylene substrate, manufactured by Nippon Polypropylene Co., Ltd., trade name "TSOP-6"). The mixture was then dried at 80°C for 5 minutes to obtain a 15 μm thick coating (primer layer). Next, a mixture of 100 g of DianalLR-7677 (manufactured by Mitsubishi Chemical Co., Ltd.), 3.8 g of aluminum paste MH-8801 (manufactured by Asahi Kasei Corporation), 20 g of a 25% by mass solution of butyl acetate from cellulose ester CAB381-0.5 (manufactured by Eastman Chemical Co., Ltd.), and 160 g of a solvent mixture (xylene / ethyl acetate / toluene / PGMAc / MIBK (mass ratio) = 10 / 60 / 30 / 30 / 30) was applied. The mixture was then left at room temperature for at least 5 minutes to obtain a 15 μm thick coating on the primer layer (1). Then, a mixture of 100g of Dianal JR-C211 (manufactured by Mitsubishi Chemical Corporation), 0.8g of surface conditioner (manufactured by BYK Chemicals Japan Co., Ltd., trade name "BYK-333"), 0.04g of curing catalyst (manufactured by Tokyo Chemical Industry Co., Ltd., trade name "BDBTDL"), 45.7g of mixed solvent (S100 / PGMAc / butyl acetate / ethyl acetate (mass ratio) = 18.3 / 13.7 / 9.1 / 4.6), and 24.3g of isocyanate polymer (manufactured by Asahi Kasei Corporation, trade name "Duranate TPA-100") was applied. The mixture was then left at room temperature for 15 minutes and dried at 80°C for 30 minutes to form a 40μm thick coating on coating (1). After forming the three-layer coating consisting of the primer layer, coating (1), and coating (2), cross-shaped cuts were made in the coating using a cutter.

[0279] Using testing equipment (Kärcher, product name "HDS4 / 7C"), the coating was sprayed with high-pressure warm water at a spray angle of 90 degrees for 1 minute under the conditions of water pressure of 6 MPa, water flow rate of 7 L / min, and water temperature of 65°C. More specifically, as... Figure 1 As shown, high-pressure hot water is sprayed onto the cross-shaped cut of the coating 11 from the tip of the nozzle 10 of the test equipment. After spraying, the coating is observed to confirm whether peeling has occurred. If no peeling occurs, as shown... Figure 1 As shown, the same test was performed after further shortening the spray distance d. This was repeated until the coating peeled off. For example, as... Figure 2 As shown, the spray distance d is recorded when the cross-shaped cut 12 of the coating 11 peels off. The smaller the spray distance d, the better the adhesion during high-temperature and high-pressure cleaning.

[0280] It should be noted that "PGMAc" is propylene glycol monomethyl ether acetate, "MIBK" is methyl isobutyl ketone, and "S100" is a high-boiling-point aromatic hydrocarbon solvent (manufactured by Andoh Parachemie Co., Ltd.).

[0281] In addition, for the case where Kingfa Science & Technology Co., Ltd.'s trade name "ABP-1010" is used as the olefin substrate, the same method was used to evaluate the adhesion during high-temperature and high-pressure cleaning.

[0282] As the substrate, a polymer substrate is preferred, such as olefin substrates, acrylonitrile / butadiene / styrene copolymer (ABS polymer) substrates, polycarbonate substrates, polymethyl methacrylate substrates (acrylic polymers), polystyrene substrates, and polyamide substrates (nylon substrates). Among these, the coating film formed by the aqueous polymer dispersion of this embodiment exhibits excellent adhesion to olefin substrates and ABS polymer substrates, especially excellent adhesion to olefin substrates.

[0283] Examples of olefin-based substrates include vinyl and acrylic substrates. To improve the adhesion of the coating film to the substrate after high-temperature and high-pressure cleaning, acrylic substrates are preferred, and polypropylene substrates containing elastomer components such as rubber are more preferred.

[0284] A coating, for example, can be obtained by coating a substrate with an aqueous polymer dispersion and drying to remove the aqueous medium.

[0285] There are no particular limitations on the coating method; common methods can be used, such as spin coating, slot coating, spray coating, gravure coating, bar coating, and roller coating.

[0286] The drying temperature is not particularly limited as long as it is a temperature that can remove the aqueous medium. For example, it is preferably 60~140°C, more preferably 70~120°C.

[0287] The thickness of the coating is not particularly limited and can be appropriately determined according to the application. For example, it is preferably 0.1 to 100 μm, and more preferably 1 to 50 μm.

[0288] (use)

[0289] Aqueous polymer dispersions can be effectively used in coatings such as primers and topcoats, as well as adhesives such as binders and inks.

[0290] Applications of aqueous polymer dispersions include, for example, automotive coatings for automotive interiors, automotive exteriors, coatings for household appliances such as mobile phones and computers, coatings for building materials, and heat sealants. Among these, applications as coatings are preferred, and applications as primer compositions (primer coatings) for olefin-based substrates are particularly preferred.

[0291] Coatings, adhesives, and inks containing aqueous polymer dispersions may, as needed, contain components other than the aqueous polymer dispersion (hereinafter also referred to as "other components"). Examples of other components include, for instance, any component already listed in the description of the aqueous polymer dispersion. Furthermore, other polymers besides the aqueous polymer dispersion (other adhesive components) may also be included as other components.

[0292] Other adhesive components include, for example, polyolefin polymers, polyurethane polymers, and polyester polymers. For instance, a polyolefin polymer can be mixed as another component into an aqueous polymer dispersion containing composite particles of an olefin polymer (A) and an acrylic polymer (B) to create coatings, adhesives, and inks. In this case, the polyolefin polymer, as another component, exists independently of the composite particles of the olefin polymer (A) and the acrylic polymer (B), and is not integrated with the acrylic polymer.

[0293] For example, by coating the aqueous polymer dispersion of this embodiment onto a substrate and drying it, a laminate comprising the substrate and a layer (coating) formed by drying the aqueous polymer dispersion of this embodiment on the substrate can be formed. Examples of substrates include the substances described above; the present invention is effective for olefin substrates and particularly effective for propylene substrates.

[0294] The laminate may further have other coatings on the layer (coating) formed by drying the aqueous polymer dispersion of this embodiment. For example, a layer formed by drying the aqueous polymer dispersion of this embodiment may be provided on the surface of the substrate as a primer layer, and a colored layer or a clear varnish layer may be provided on the primer layer by means of a paint or a varnish.

[0295]

Example

[0296] The present invention will be further described in detail below through embodiments. However, the present invention is not limited to the following embodiments as long as it does not depart from its spirit. Various modifications can be made without departing from the spirit of the present invention.

[0297] [Measurement and Evaluation]

[0298] The detailed methods for measurement and evaluation in the examples are described below.

[0299] (Average particle size of aqueous polymer dispersion)

[0300] The average particle size of the aqueous polymer dispersion was determined using a high-concentration system particle size analyzer, "FPAR-1000" (manufactured by Otsuka Electronics Co., Ltd.), to calculate the cumulative diameter of the aqueous polymer dispersion.

[0301] (Composition ratio of each olefin component)

[0302] An aqueous dispersion (α) was vacuum dried at 40°C for 12 hours, then dichlorobenzene was added to a concentration of 2% by mass, and dissolved at 100°C to prepare an NMR sample. An NMR spectroscopy instrument (JNM-ECS400, manufactured by NEC Corporation) was used to measure nuclides at a frequency of 400 MHz. 13 C. NMR spectra were determined under the following conditions: pulse width 3.47 μs, pulse repetition time 3.04 s, measurement temperature 100℃, and 4096 scans. The results were based on the *Handbook of Polymer Analysis* (4th edition, compiled by the Japan Society for Analytical Chemistry's Polymer Analysis Research Conference) and *Study of Propylene-1-butene-ethylene Terpolymer and Reactor Blend by TREF and... 13 C-NMR (using TREF and 13 The method described in the C-NMR study of propylene-1-butene-ethylene terpolymers and their reactor blends (authors: Adilson Arli Silva Filho, Griselda Barrera Galland, Journal of Applied Polymer Science) was used to assign spectra. Then, the composition ratio of each olefin component was calculated based on the peak area ratio of each olefin component.

[0303] (Adhesion during high-temperature and high-pressure cleaning)

[0304] Aqueous polymer dispersions were coated onto an olefin substrate (propylene substrate, manufactured by Nippon Polypropylene Co., Ltd., trade name "TSOP-6"). The mixture was then dried at 80°C for 5 minutes to obtain a 15 μm thick coating (primer layer). Next, a mixture of 100 g of DianalLR-7677 (manufactured by Mitsubishi Chemical Co., Ltd.), 3.8 g of aluminum paste MH-8801 (manufactured by Asahi Kasei Corporation), 20 g of a 25% by mass solution of butyl acetate from cellulose ester CAB381-0.5 (manufactured by Eastman Chemical Co., Ltd.), and 160 g of a solvent mixture (xylene / ethyl acetate / toluene / PGMAc / MIBK (mass ratio) = 10 / 60 / 30 / 30 / 30) was applied. The mixture was then left at room temperature for at least 5 minutes to obtain a 15 μm thick coating on the primer layer (1). Then, a mixture of 100g of Dianal JR-C211 (manufactured by Mitsubishi Chemical Corporation), 0.8g of surface conditioner (manufactured by BYK Chemicals Japan Co., Ltd., trade name "BYK-333"), 0.04g of curing catalyst (manufactured by Tokyo Chemical Industry Co., Ltd., trade name "BDBTDL"), 45.7g of mixed solvent (S100 / PGMAc / butyl acetate / ethyl acetate (mass ratio) = 18.3 / 13.7 / 9.1 / 4.6), and 24.3g of isocyanate polymer (manufactured by Asahi Kasei Corporation, trade name "Duranate TPA-100") was applied. The mixture was then left at room temperature for 15 minutes and dried at 80°C for 30 minutes to form a 40μm thick coating on coating (1). After forming the three-layer coating consisting of the primer layer, coating (1), and coating (2), cross-shaped cuts were made in the coating using a cutter.

[0305] Using testing equipment (Kärcher, product name "HDS4 / 7C"), the coating was sprayed with high-pressure warm water at a spray angle of 90 degrees for 1 minute under the conditions of water pressure of 6 MPa, water flow rate of 7 L / min, and water temperature of 65°C. More specifically, as... Figure 1 As shown, high-pressure hot water is sprayed onto the cross-shaped cut of the coating 11 from the tip of the nozzle 10 of the test equipment. After spraying, the coating is observed to confirm whether peeling has occurred. If no peeling occurs, as shown... Figure 1 As shown, the same test was performed after further shortening the spray distance d. This was repeated until the coating peeled off. For example, as... Figure 2 As shown, the spray distance d is recorded when the cross-shaped cut 12 of the coating 11 peels off. The smaller the spray distance d, the better the adhesion during high-temperature and high-pressure cleaning.

[0306] It should be noted that "PGMAc" is propylene glycol monomethyl ether acetate, "MIBK" is methyl isobutyl ketone, and "S100" is a high-boiling-point aromatic hydrocarbon solvent (manufactured by Andoh Parachemie Co., Ltd.).

[0307] In addition, for the case where Kingfa Science & Technology Co., Ltd.'s trade name "ABP-1010" is used as the olefin substrate, the same method was used to evaluate the adhesion during high-temperature and high-pressure cleaning.

[0308] [Preparation of olefin-based polymer (A)]

[0309] (Manufacturing Example 1: Manufacturing and Analysis of Composite Polymer (a31))

[0310] 200 kg of propylene-butene copolymer (manufactured by Mitsui Chemicals Co., Ltd., trade name "Tafmer XM-7070", melting point 75°C, propylene content 70 mol%, weight average molecular weight [Mw] 250,000 (converted to polypropylene), molecular weight distribution [Mw / Mn] 2.2) polymerized with metallocene catalyst and 5 kg of maleic anhydride were dry-mixed using a super mixer.

[0311] Then, using a twin-screw extruder (manufactured by Nippon Steel Corporation, product name "TEX54α Ⅱ"), tert-butyl peroxyisopropyl monocarbonate (manufactured by Nippon Oil Corporation, trade name "Perbutyl I") was added mid-process using a liquid addition pump at a barrel temperature of 200°C, a screw speed of 125 rpm, and an extrusion rate of 80 kg / time to obtain granular maleic anhydride modified propylene-butene copolymer (equivalent to olefin copolymer (A21)).

[0312] The resulting maleic anhydride-modified propylene-butene copolymer had a maleic anhydride group content (grafting rate) of 1.0% by mass (0.1 mmol / g as maleic anhydride group and 0.2 mmol / g as carboxylic acid group). Furthermore, the weight-average molecular weight (converted from polystyrene) [Mw] was 156,000 and the number-average molecular weight [Mn] was 84,000.

[0313] Then, in a glass flask equipped with a reflux condenser, thermometer, and stirrer, 72g of the previously obtained maleic anhydride-modified propylene-butene copolymer, 48g of the propylene-butene copolymer (manufactured by Mitsui Chemicals Co., Ltd., trade name "TafmerXM-7070"), and 79.9g of toluene were added. The inside of the container was purged with nitrogen, and the temperature was raised to 110°C. After heating, 1.8g of maleic anhydride and 0.9g of tert-butylperoxyisopropyl monocarbonate (manufactured by Nippon Oil Co., Ltd., trade name "Perbutyl I") were added, and the reaction was carried out with continuous stirring at 110°C for 7 hours.

[0314] The maleic anhydride content (grafting rate) of the obtained maleic anhydride modified propylene-butene copolymer (polyolefin (A-1)) was 2.0% by mass (0.2 mmol / g as maleic anhydride group and 0.4 mmol / g as carboxylic acid group).

[0315] After the reaction was complete, the reaction system was cooled to near room temperature, and 85.7 g of toluene was added. Then, 24 g of polyetheramine (manufactured by Huntsman, trade name "Jeffamine M-2005") dissolved in 156 g of 2-propanol was added (equivalent to 20 parts by mass of polyether polymer per 100 parts by mass of polyolefin (A-1)). The reaction was carried out at 70°C for 1 hour. Then, 12 g of polyetheramine (manufactured by Huntsman, trade name "Jeffamine M-1000") dissolved in 84 g of 2-propanol was added (equivalent to 10 parts by mass of polyether polymer per 100 parts by mass of polyolefin (A-1)). The reaction was carried out at 70°C for 1 hour.

[0316] Then, 1.8 g of dimethylethanolamine, 62 g of water, and 45 g of 2-propanol were added to neutralize the reaction system. The temperature of the resulting reaction solution was maintained at 50 °C while heating and stirring. 434.4 g of water was added dropwise while the pressure in the reaction system was reduced. Toluene and 2-propanol were removed by vacuum distillation until the polymer concentration reached 30% by mass, resulting in an aqueous dispersion (α) of a milky white composite polymer (a31).

[0317] [Example 1]

[0318] In a flask equipped with a stirrer, a reflux condenser and a temperature control device, 222.2 parts by mass of the aqueous dispersion (α) of the previously obtained composite polymer (a31) (equivalent to 66.6 parts by mass in terms of solid content) were added, along with 178.95 parts by mass of deionized water, and the temperature was raised to 30°C.

[0319] In addition, a pre-emulsion was prepared by emulsifying a mixture of 45.8 parts by weight of isobornyl methacrylate (IBXMA) as monomer (b11), 9.4 parts by weight of 2-hydroxyethyl methacrylate (HEMA), 44.8 parts by weight of styrene as monomer (b2), 7 parts by weight of reactive surfactant (manufactured by ADEKA Co., Ltd., trade name "ADEKA Reasoap SR-1025") and 45 parts by weight of deionized water using a TK homogenizer.

[0320] 152.0 g of the obtained preemulsion was added to a flask containing an aqueous dispersion (α), and the mixture was heated to 55°C while stirring, and maintained at this temperature for 1.5 hours. Then, while maintaining the temperature at 55°C, 0.05 parts by weight of initiator (manufactured by Nippon Oil Co., Ltd., trade name "Perbutyl (registered trademark) H69", solid content 69% by weight), 0.0002 parts by weight of ferrous sulfate as a reducing agent, 0.00027 parts by weight of ethylenediaminetetraacetic acid (EDTA), 0.08 parts by weight of sodium isoascorbate monohydrate, and 2 parts by weight of deionized water were added to initiate polymerization. After detecting the exothermic peak of polymerization, 0.06 parts by weight of initiator (manufactured by Nippon Oil Co., Ltd., trade name "Perbutyl (registered trademark) H69") and 12 parts by weight of deionized water were further added. Then, after aging at 60°C for 30 minutes, an aqueous polymer dispersion of composite particles of composite polymer (a31) and acrylic polymer (B) was obtained in an aqueous medium, with an average particle size of 84 nm and a solid content of 30% by mass.

[0321] PO polymer, PUD, pigment, solvent, wetting agent, and defoamer were mixed into 111.1 parts by mass (equivalent to 33.33 parts by mass of solids) of the obtained aqueous polymer dispersion according to the formulations shown in Table 1, and the adhesion during high-temperature and high-pressure cleaning was evaluated. The results are shown in Table 1. In addition, the composition ratio of each olefin component in the aqueous dispersion (α) was determined, and the Tg of the acrylic polymer (B) was calculated using the Fox calculation formula shown in Equation (2). The calculation results are shown in Table 1.

[0322] [Examples 2-4, Comparative Examples 1 and 2]

[0323] Except for changing the content of the polyolefin polymer (A) and the content of the monomers used in the acrylic polymer (B) as shown in Table 1, Example 1 and the aqueous polymer dispersion were obtained and evaluated in the same way.

[0324] The Tg of the homopolymers of the monomers used in the examples and comparative examples are shown below.

[0325] IBXMA: Isobornyl methacrylate (Tg: 180℃)

[0326] IBMA: Isobutyl methacrylate (Tg: 48℃)

[0327] 2EHA: 2-Ethylhexyl acrylate (Tg: -55℃)

[0328] St: Styrene (Tg: 100℃)

[0329] HEMA: 2-Hydroxyethyl methacrylate (Tg: 55℃)

[0330] 4HBA: 4-Hydroxybutyl acrylate (Tg: -85.5℃)

[0331] Table 1

[0332]

[0333] In Table 1, "parts" refers to "parts by weight". "PO polymer" is a polyolefin polymer (trade name "APTOLOK (registered trademark) BW-5710" manufactured by Mitsubishi Chemical Corporation). "PUD" is "Bayhydrol UH-2648 / 1" manufactured by Covestro. "Pigment" is "WT-9004" manufactured by Nippon Pigment Co., Ltd. "Solvent" is "BDG" manufactured by Nippon Emulsifier Co., Ltd. "Wetting agent" is "TEGO WetKL245" manufactured by Evonik Industries, Inc. "Defoamer" is "BYK-028" manufactured by BYK Chemicals Japan Co., Ltd. The content of PO polymer, PUD, pigment, solvent, wetting agent, and defoamer is the solid component, i.e., the tangible amount (parts by weight). When any of the PO polymer, PUD, pigment, wetting agent, and defoamer contains solvents, the value includes those solvents.

[0334] The blank space in the table means that the ingredient was not mixed (0 parts by mass).

[0335] In Examples 1-4, the spray distance d at which the coating peeled off during the high-temperature and high-pressure cleaning test was shorter than that in Comparative Examples 1-2. That is, the adhesion during high-temperature and high-pressure cleaning in Examples 1-4 was better than that in Comparative Examples 1-2.

[0336] Industrial availability

[0337] According to the present invention, a coating film can be formed that maintains adhesion to substrates such as olefin substrates even during high-temperature and high-pressure cleaning.

Claims

1. An aqueous polymer dispersion comprising an olefin polymer A and an acrylic polymer B dispersed in an aqueous medium. The glass transition temperature of the acrylic polymer B is above 105°C. The mass ratio of the olefin polymer A to the acrylic polymer B is A:B = 25:75~99:

1.

2. The aqueous polymer dispersion according to claim 1, wherein, The glass transition temperature of the acrylic polymer B is above 110°C.

3. The aqueous polymer dispersion according to claim 1, wherein, The glass transition temperature of the acrylic polymer B is below 250°C.

4. The aqueous polymer dispersion according to claim 1, wherein, The acrylic polymer B contains structural units derived from isobornyl methacrylate.

5. The aqueous polymer dispersion according to claim 1, wherein, The olefin polymer A and the acrylic polymer B form composite particles.

6. The aqueous polymer dispersion according to claim 5, wherein, It comprises composite particles formed by the integration of the olefin polymer A and the acrylic polymer B through covalent bonds.

7. The aqueous polymer dispersion according to claim 1, wherein, The olefin polymer A comprises at least one selected from the group consisting of ethylene-propylene copolymers, ethylene-propylene-butene copolymers, and propylene-butene copolymers.

8. The aqueous polymer dispersion according to claim 1, wherein, The olefin polymer A has reactive groups.

9. The aqueous polymer dispersion according to claim 5, wherein, The reactive group comprises at least one selected from the group consisting of carboxyl, epoxy, isocyanate, sulfonic acid and hydroxyl groups.

10. The aqueous polymer dispersion according to claim 1, wherein, The average particle size of the aqueous polymer dispersion is below 500 nm.

11. The aqueous polymer dispersion according to claim 1, wherein, The total content of the olefin polymer A and the acrylic polymer B relative to the total mass of the aqueous polymer dispersion is 5 to 80% by mass.

12. A coating, characterized in that, The aqueous polymer dispersion contains any one of claims 1 to 11.

13. A primer composition, characterized in that, The aqueous polymer dispersion contains any one of claims 1 to 11.

14. A laminated body, characterized in that, It comprises a substrate and a layer disposed on the substrate, which is formed by drying the aqueous polymer dispersion according to any one of claims 1 to 11.

15. The laminate according to claim 14, wherein, The substrate is a polyolefin substrate.

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