Resin dispersion, paint, adhesive, and laminate

Abstract

To provide a resin dispersion enabling formation of a coating film having superior adhesion to a polyolefin substrate, superior water resistance, and high peel strength even under low-temperature drying; a paint and an adhesive containing the resin dispersion; and a laminate produced using the resin dispersion.SOLUTION: An olefin resin dispersion according to one example comprises a composition (I) comprising a polyolefin (A) and a nucleating agent (E). The melting point of the composition (I) may be 20°C to 120°C. The crystallization temperature of the composition (I) may be 20°C to 100°C.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a resin dispersion, a coating material, an adhesive, and a laminate. [Background technology]

[0002] Polyolefins, such as propylene polymers or propylene-α-olefin copolymers, are inexpensive and have excellent mechanical properties, heat resistance, chemical resistance, and water resistance, making them widely used in a wide range of fields, including automobiles, home appliances, and food packaging. However, polyolefins generally have low polarity because they do not contain polar groups in their molecules, making them difficult to paint or adhere.

[0003] In order to improve the paintability and adhesion of polyolefin molded articles, various surface treatment methods have been proposed, such as chemical treatment with chemicals, and oxidation treatment by corona discharge treatment, plasma treatment, or flame treatment, etc. However, these methods require special equipment and are not necessarily effective in improving paintability and adhesion.

[0004] Therefore, in order to provide polyolefins with good paintability and adhesiveness in a relatively simple manner, a method has been developed in which so-called modified polyolefin resins are applied to the surface of polyolefin molded articles as surface treatment agents, adhesives, paints, etc. The modified polyolefin resins referred to here include chlorinated polypropylene, acid-modified propylene-α-olefin copolymers, acid-modified chlorinated polypropylene, etc. These modified polyolefin resins are usually applied in the form of a solution in an organic solvent or a dispersion in water, but in recent years, aqueous resin dispersions have been preferred from the standpoints of safety and hygiene and environmental pollution.

[0005] As aqueous resin dispersions of modified polyolefin resins, for example, the following have been proposed. Aqueous resin composition in which acid-modified chlorinated polyolefin is made water-soluble using a surfactant and a basic substance (Patent Document 1) Aqueous resin compositions in which acid-modified polyolefins are made water-soluble using surfactants and basic substances (Patent Documents 2 and 3)

[0006] In recent years, it has been proposed to lower the melting point of polyolefins relatively in order to further improve adhesion (Patent Document 4). [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Publication No. 3-182534 [Patent Document 2] Japanese Patent Application Publication No. 6-256592 [Patent Document 3] US Patent Application Publication No. 2005 / 0100754 [Patent Document 4] Japanese Patent Application Laid-Open No. 2016-35054 Summary of the Invention [Problem to be solved by the invention]

[0008] However, the previously proposed methods have had the problem that after the aqueous resin dispersion is applied to a polyolefin substrate, it is not possible to form a coating film with excellent adhesion when the aqueous resin dispersion is dried at low temperature.

[0009] The present invention aims to provide a resin dispersion that can give a coating film that has excellent adhesion to polyolefin substrates, water resistance, and peel strength even when dried at low temperatures; a paint and adhesive that contain the resin dispersion; and a laminate that uses the resin dispersion. [Means for solving the problem]

[0010] As a result of extensive research to achieve the above object, the present inventors have found that by using a nucleating agent (E) in addition to the polyolefin (A) in a resin dispersion containing a polyolefin, a coating film having excellent adhesion to a polyolefin substrate can be obtained.

[0011] The present invention has the following aspects. [1] A resin dispersion comprising a composition (I) containing a polyolefin (A) and a crystal nucleating agent (E). [2] The resin dispersion according to [1], wherein the melting point of the composition (I) is 20 to 120°C. [3] The resin dispersion according to [1] or [2], wherein the crystallization temperature of the composition (I) is 20 to 100°C. [4] The resin dispersion according to any one of [1] to [3], wherein the polyolefin (A) is a homopolymer of propylene or a copolymer of propylene and another comonomer. [5] The resin dispersion according to any one of [1] to [4], wherein the polyolefin (A) is a copolymer of propylene and butene. [6] The resin dispersion according to any one of [1] to [5], wherein the polyolefin (A) is a polyolefin (A1) having a reactive group. [7] The resin dispersion according to any one of [1] to [6], wherein the content of the crystal nucleating agent (E) is 0.01 to 10 parts by mass per 100 parts by mass of the polyolefin (A). [8] The resin dispersion according to any one of [1] to [7], wherein the crystal nucleating agent (E) is a sorbitol. [9] The resin dispersion according to any one of [1] to [8], which is an aqueous resin dispersion in which at least the polyolefin (A) is dispersed in water.

[10] A coating material containing the resin dispersion according to any one of [1] to [9].

[11] An adhesive containing the resin dispersion according to any one of [1] to [9].

[12] A substrate and a resin layer provided on a surface of the substrate, A laminate, wherein the resin layer is formed by heating a coating film of the resin dispersion according to any one of [1] to [9].

[13] A substrate and a resin layer provided on a surface of the substrate, A laminate in which the resin layer is formed by heating a coating film of the paint according to

[10] . [Effects of the Invention]

[0012] The resin dispersion of the present invention can provide a coating film that has excellent adhesion to a polyolefin substrate even when dried at low temperature. DETAILED DESCRIPTION OF THE INVENTION

[0013] The meanings of the terms are as follows: "(Meth)acrylic" is a general term for "acrylic" and "methacrylic." The "copolymer" may be a random copolymer or a block copolymer. The symbol "to" indicating a range of values ​​means that the values ​​before and after it are included as the lower and upper limits. The numerical ranges disclosed in this specification can be combined in any manner to form new numerical ranges.

[0014] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The following describes in detail the preferred embodiments of the present invention. However, the following description is a representative example, and the present invention is not limited to the following description.

[0015] The resin dispersion contains a composition (I) containing a polyolefin (A) and a crystal nucleating agent (E). In one example, a polyether resin (B) may be bonded to the polyolefin (A). In this case, a polymer (C) can be produced in which the polyether resin (B) is bonded to the polyolefin (A).

[0016] [Polyolefin (A)] The polyolefin (A) may be a polyolefin (A1) having no reactive group or a polyolefin (A2) having a reactive group. The polyolefin (A) may be linear or branched.

[0017] (Polyolefin (A1) having no reactive group) The polyolefin (A1) having no reactive group may be any of various known polyolefins and modified polyolefins, including, but not limited to, homopolymers of ethylene or propylene, copolymers of ethylene and propylene, and copolymers of ethylene and / or propylene with other comonomers.

[0018] Specific examples of the copolymer of ethylene and / or propylene with other comonomers include copolymers of ethylene and / or propylene with α-olefin comonomers having two or more carbon atoms, such as butene-1, pentene-1, hexene-1, heptene-1, octene-1, cyclopentene, cyclohexene, and norbornene, and copolymers of two or more of these comonomers.

[0019] The α-olefin comonomer is preferably an α-olefin comonomer having 2 to 6 carbon atoms. Also usable are copolymers of an α-olefin comonomer with a comonomer such as vinyl acetate or a (meth)acrylic acid ester, copolymers of an α-olefin comonomer with a comonomer such as an aromatic vinyl monomer or hydrogenated products thereof, and conjugated diene block copolymers or hydrogenated products thereof.

[0020] Furthermore, chlorinated polyolefins obtained by chlorinating these polyolefins can also be used. The chlorination degree of the chlorinated polyolefin is usually 5% by weight or more, preferably 10% by weight or more, and the chlorination degree is usually 50% by weight or less, preferably 30% by weight or less.

[0021] Specific examples of the polyolefin (A1) include polyethylene, polypropylene, ethylene-propylene copolymer, propylene-butene copolymer, propylene-hexene copolymer, chlorinated polyethylene, chlorinated polypropylene, chlorinated ethylene-propylene copolymer, chlorinated propylene-butene copolymer, ethylene-vinyl acetate copolymer, hydrogenated styrene-butadiene-styrene block copolymer (SEBS), and hydrogenated styrene-isoprene-styrene block copolymer (SEPS).

[0022] The polyolefin (A1) is preferably a propylene homopolymer or a copolymer of propylene and another α-olefin, which may be chlorinated. More preferably, it is a substantially chlorine-free propylene homopolymer, an ethylene-propylene copolymer, a propylene-butene copolymer, or an ethylene-propylene-butene copolymer. These may be used alone or in combination of two or more.

[0023] The melting point of the polyolefin (A1) is preferably not more than 125° C., more preferably not more than 100° C., and even more preferably not more than 90° C. The lower the melting point of the polyolefin (A1), the more likely it is that high adhesion can be obtained even when dried at a low temperature.

[0024] The polyolefin (A1) is preferably a polypropylene polymer containing 50 mol % to 100 mol % of a propylene component. The propylene content of the polyolefin (A1) is more preferably 60 mol % or more, and even more preferably 70 mol % or more.

[0025] Generally, the higher the propylene content, the stronger the adhesion to a polypropylene substrate tends to be. The propylene content is the ratio of propylene-derived structural units to all monomer-derived structural units constituting the polyolefin (A1).

[0026] When the polyolefin (A1) is a propylene homopolymer or a polypropylene copolymer, it is preferable that the stereoregularity thereof has a wholly or partially isotactic structure. For example, not only ordinary isotactic polypropylene but also isotactic block polypropylene, stereoblock polypropylene, etc. as described in known documents such as JP-A-2003-231714 and U.S. Pat. No. 4,522,982 can be used.

[0027] A preferred example of polyolefin (A1) is a stereoblock polypropylene homopolymer or copolymer having an isotactic block and an atactic block. Preferably, the [mmmm] pentads showing isotactic stereoregularity are in the range of 20% to 90%. The lower limit of the pentad ratio is preferably 30%, more preferably 35%. The upper limit of the pentad ratio is preferably 80%, more preferably 70%, and even more preferably 60%.

[0028] The higher the pentad ratio is, the lower the stickiness tends to be. The lower the pentad ratio is, the lower the crystallinity tends to be, and the easier it is to prepare the resin dispersion. The pentad ratio can be measured by the method described in JP 2003-231714 A.

[0029] Other commonly available polypropylene polymers include, for example, "Wintec" and "Wellnex" manufactured by Japan Polypropylene Corporation, "Tafmer XM" manufactured by Mitsui Chemicals, Inc., and "Licothene PP" manufactured by Clariant, all of which are polypropylene copolymers polymerized using a metallocene catalyst.

[0030] The weight average molecular weight [Mw] of the polyolefin (A1) is preferably at least 5000. The weight average molecular weight [Mw] of the polyolefin (A1) is a value measured by GPC (Gel Permeation Chromatography) and converted using the calibration curve of each polyolefin.

[0031] The lower limit of Mw is more preferably 10,000, even more preferably 30,000, even more preferably 100,000, and most preferably 200,000. The upper limit of Mw is not particularly limited. As Mw is higher than the lower limit, the degree of stickiness tends to decrease and adhesion to the substrate tends to increase. As Mw increases, the peel strength tends to increase. Usually, the upper limit is 1,000,000.

[0032] The molecular weight distribution [Mw / Mn] of the polyolefin (A1) is preferably 10 to 1, more preferably 5 to 1, and even more preferably 3 to 1. The molecular weight distribution [Mw / Mn] is the ratio of the weight average molecular weight [Mw] to the number average molecular weight [Mn] measured by GPC and converted using the calibration curve of each polyolefin.

[0033] If the [Mw / Mn] is higher than the lower limit, the viscosity will be lower during production and production will tend to be easier. If the [Mw / Mn] is lower than the upper limit, particle size control during dispersion in water will be easier, and the particle size distribution will tend to be narrower and the dispersion will be more stable.

[0034] The GPC measurement is carried out by a conventional method using a commercially available apparatus and a solvent such as orthodichlorobenzene, as specifically described in the Examples section below.

[0035] The method for producing the polyolefin (A1) is not particularly limited and may be any method, such as radical polymerization, cationic polymerization, anionic polymerization, and coordination polymerization, each of which may be a living polymerization.

[0036] In the case of coordination polymerization, for example, polymerization using a Ziegler-Natta catalyst, or polymerization using a single-site catalyst or Kaminsky catalyst is used. A preferred production method is the use of a single-site catalyst. This is because single-site catalysts generally have a sharp molecular weight distribution or stereoregularity distribution due to the design of the ligand.

[0037] Examples of single-site catalysts include metallocene catalysts and Brookhart catalysts. A preferred metallocene catalyst may be selected from C1 symmetric, C2 symmetric, C2V symmetric, or CS symmetric catalysts depending on the stereoregularity of the polyolefin to be polymerized. Preferably, a C1 symmetric or C2 symmetric metallocene catalyst can be used.

[0038] In a preferred embodiment, the polyolefin (A1) may be produced by a polymerization reaction in the presence of a metallocene catalyst.

[0039] The polymerization may be any polymerization form such as solution polymerization, slurry polymerization, bulk polymerization, or gas phase polymerization. In the case of solution polymerization or slurry polymerization, examples of the solvent include aromatic hydrocarbons such as toluene and xylene, aliphatic hydrocarbons such as hexane, octane, and decane, alicyclic aliphatic hydrocarbons such as cyclohexane and methylcyclohexane, halogenated hydrocarbons such as chloroform and chlorobenzene, esters such as ethyl acetate and butyl acetate, ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone, alcohols such as methanol, ethanol, isopropanol, and n-butanol, ethers such as dibutyl ether and tetrahydrofuran, and polar solvents such as dimethylformamide and dimethyl sulfoxide.

[0040] Among these, aromatic hydrocarbons, aliphatic hydrocarbons and alicyclic hydrocarbons are preferred, and toluene, xylene, hexane, heptane, cyclopentane and cyclohexane are more preferred. These may be used alone or in combination of two or more.

[0041] (Polyolefin (A2) having reactive groups) Examples of reactive groups possessed by the polyolefin (A2) having a reactive group include carboxylic acid groups, dicarboxylic anhydride groups, dicarboxylic anhydride monoester groups, hydroxyl groups, amino groups, epoxy groups, and isocyanate groups. The reactive group of the polyolefin (A2) is preferably at least one selected from the group consisting of carboxylic acid groups, dicarboxylic anhydride groups, and dicarboxylic anhydride monoester groups. These carboxylic acid groups are highly reactive and easily bonded to the polyether resin (B), and many unsaturated compounds also contain these groups. Therefore, copolymerization and grafting reactions for introducing reactive groups into the polyolefin are also easy.

[0042] Examples of the polyolefin (A2) having a reactive group include a copolymer (A2a) obtained by copolymerizing an unsaturated compound that does not have a reactive group during polymerization with an unsaturated compound that has a reactive group, and a copolymer (A2b) obtained by graft polymerizing a radically polymerizable unsaturated compound that has a reactive group onto a polyolefin.

[0043] As the polyolefin (A2) having a reactive group, either copolymer (A2a) or copolymer (A2b) can be used, but copolymer (A2b) is usually preferred. Copolymer (A2b) has the advantage that it is easy to control the amount of polyether resin (B) bonded to it, which will be described later.

[0044] The copolymer (A2a) is obtained by copolymerizing an unsaturated compound having no reactive group with an unsaturated compound having a reactive group, and is a copolymer in which the unsaturated compound having a reactive group is inserted into the main chain. For example, it can be obtained by copolymerizing an α-olefin such as ethylene, propylene, or butene with an α,β-unsaturated carboxylic acid or an anhydride thereof such as acrylic acid or maleic anhydride.

[0045] Specific examples of the copolymer (A2a) include ethylene-acrylic acid copolymer and ethylene-acrylic acid ester-maleic anhydride copolymer. These may be used alone or in combination of two or more. The copolymer (A2a) can be produced by the same method as described for the polyolefin (A1).

[0046] The copolymer (A2b) is obtained by graft polymerizing a radically polymerizable unsaturated compound having a reactive group onto a prepolymerized polyolefin, and is a polymer in which the unsaturated compound having a reactive group is grafted onto the main chain.

[0047] For example, it is a polymer obtained by grafting a polyolefin such as polyethylene or polypropylene with (meth)acrylic acid, fumaric acid, maleic acid or its anhydride, itaconic acid or its anhydride, crotonic acid, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, (meth)acrylamide, (dimethylamino)ethyl (meth)acrylate, glycidyl (meth)acrylate, (2-isocyanato)ethyl (meth)acrylate, etc. These may be used alone or in combination of two or more.

[0048] As the polyolefin for the present reaction to obtain the copolymer (A2b), the above-mentioned polyolefin (A1) having no reactive group can be used.

[0049] The radical polymerization initiator used in the graft polymerization can be appropriately selected from common radical initiators, and examples thereof include organic peroxides and azonitrile.

[0050] Examples of organic peroxides include peroxyketals such as di(t-butylperoxy)cyclohexane, hydroperoxides such as cumene hydroperoxide, dialkyl peroxides such as di(t-butyl)peroxide, diacyl peroxides such as benzoyl peroxide, and peroxyesters such as t-butylperoxyisopropyl monocarbonate.

[0051] Examples of azonitriles include azobisbutyronitrile and azobisisopropylnitrile. Among them, benzoyl peroxide and t-butylperoxyisopropyl monocarbonate are particularly preferred. These may be used alone or in combination of two or more.

[0052] The ratio of the radical polymerization initiator to the radically polymerizable unsaturated compound having a reactive group used is usually radical polymerization initiator:radically polymerizable unsaturated compound having a reactive group=in the range of 1:100 to 2:1 (molar ratio), preferably in the range of 1:20 to 1:1.

[0053] The method for producing the copolymer (A2b) is not particularly limited, and any method may be used. Examples include a method of reacting the copolymer (A2b) in a solution by heating and stirring, a method of reacting the copolymer (A2b) in a melt by heating and stirring without a solvent, and a method of reacting the copolymer (A2b) by heating and kneading in an extruder. The solvent for producing the copolymer (A2b) in a solution is preferably a polyolefin (A2b). The solvents mentioned as solvents used in the production of 1) can be used in the same manner.

[0054] The reaction temperature is usually 50° C. or higher, preferably in the range of 80 to 250° C. The reaction time is usually about 1 to 20 hours.

[0055] Specific examples of the copolymer (A2b) include maleic anhydride-modified polypropylene and its chlorinated derivatives, maleic anhydride-modified ethylene-propylene copolymer and its chlorinated derivatives, maleic anhydride-modified propylene-butene copolymer, acrylic acid-modified polypropylene and its chlorinated derivatives, acrylic acid-modified ethylene-propylene copolymer and its chlorinated derivatives, and acrylic acid-modified propylene-butene copolymer, etc. These may be used alone or in combination of two or more.

[0056] The weight average molecular weight [Mw] of the polyolefin (A2) having a reactive group is preferably 5,000 to 300,000. The weight average molecular weight [Mw] of the polyolefin (A2) having a reactive group is a value measured by GPC and converted using a polystyrene calibration curve.

[0057] The lower limit of Mw is more preferably 10,000, even more preferably 30,000, and even more preferably 100,000 or more. The upper limit of Mw is more preferably 280,000, and even more preferably 250,000. The higher Mw is than the lower limit, the less sticky the resin tends to be and the better its adhesion to the substrate tends to be. The lower Mw is than the upper limit, the lower the viscosity tends to be and the easier it is to prepare the resin dispersion.

[0058] The molecular weight distribution [Mw / Mn] of the polyolefin (A2) is preferably 10 to 1, more preferably 5 to 1, and even more preferably 3 to 1. [Mw / Mn] is the ratio of the weight average molecular weight [Mw] to the number average molecular weight [Mn] measured by GPC and converted using the calibration curve of each polystyrene.

[0059] If [Mw / Mn] is higher than the above lower limit, the viscosity will be low during production and production will tend to be easier. Conversely, if it is lower than the above upper limit, particle size control during dispersion in water will be easier, and the particle size distribution will tend to be narrower and the dispersion will be more stable.

[0060] The GPC measurement is carried out by a conventional method using a commercially available apparatus and a solvent such as tetrahydrofuran (THF), as specifically described in the Examples section below.

[0061] The content of the reactive group in the reactive group-containing polyolefin (A2) is preferably 0.01 to 5 mmol per 1 g of polyolefin (A2), i.e., in the range of 0.01 to 5 mmol / g. The lower limit is more preferably 0.03 mmol / g, and particularly preferably 0.05 mmol / g. The upper limit is more preferably 1 mmol / g, and even more preferably 0.5 mmol / g.

[0062] In particular, the polyolefin (A2) having a reactive group preferably has one or more reactive groups (D) selected from the group consisting of a carboxylic acid group, a dicarboxylic anhydride group, and a dicarboxylic anhydride monoester group in a weight ratio of polyolefin (A1) not having a reactive group:reactive group (D)=100:0.1 to 100:5, more preferably polyolefin (A1):reactive group (D)=100:0.5 to 100:4, and even more preferably 100:1 to 100:3.

[0063] The higher the reactive group content of the polyolefin (A2) is from the above lower limit, the greater the amount of polyether resin (B) bonded via the reactive group, which results in increased hydrophilicity of the polymer (C) and therefore a smaller dispersed particle size. On the other hand, the lower the reactive group content is from the above upper limit, the greater the adhesion to the crystalline polyolefin substrate.

[0064] The weight ratio of the reactive group (D) in the polyolefin (A2) corresponds to the graft ratio when the polyolefin (A2) is the above-mentioned copolymer (A2b).

[0065] In the present invention, a polyolefin (A2) having a reactive group is preferred. The polyolefin (A2) has advantages such as easy control of the amount of the polyether resin (B) to be bonded, which will be described later, and a variety of reactions that can be used for bonding.

[0066] [Polyether resin (B)] In the present invention, the polyolefin (A) may be used alone, but the polyolefin (A) and the polyether resin (B) may also be used in combination. The polyether resin (B) can be any resin without particular limitation as long as it does not significantly impair the effects of the present invention, and any of synthetic polymers, semi-synthetic polymers and natural polymers can be used.

[0067] The polyether resin (B) is usually obtained by ring-opening polymerization of a cyclic alkylene oxide or a cyclic alkylene imine. The method for bonding the polyether resin (B) to the polyolefin (A) is not limited, but examples thereof include a method of ring-opening polymerization of a cyclic alkylene oxide in a polyolefin (A2) having a reactive group, and a method of reacting a reactive group of a polyether polyol or polyether amine obtained by ring-opening polymerization or the like with a reactive group of the polyolefin (A2).

[0068] Polyether polyol is a compound having a polyether skeleton and hydroxyl groups as reactive groups at both ends of the resin. Polyether amine is a compound having a polyether skeleton and primary amino groups as reactive groups at one or both ends of the resin. Preferred examples of hydrophilic polyalkylene oxides or polyalkylene imines include polyethylene oxides or polyethylene imines.

[0069] Examples of polyetheramines include Huntsman's "Jeffamine" M series, D series, and ED series, and "Surfonamin" L series.

[0070] Before bonding with the polyolefin (A), the polyether resin (B) preferably has one or more reactive groups capable of reacting with the polyolefin (A). Examples of reactive groups include carboxylic acid groups, dicarboxylic acid anhydride groups, dicarboxylic acid anhydride monoester groups, hydroxyl groups, amino groups, epoxy groups, and isocyanate groups. Among these, it is preferable for the polyether resin (B) to have at least one of an amino group and a hydroxyl group, and it is more preferable for the polyether resin (B) to have at least an amino group.

[0071] The amino group is highly reactive with various reactive groups such as a carboxylic acid group, a carboxylic anhydride group, a glycidyl group, or an isocyanate group, and therefore it is easy to bond the polyolefin (A) to the polyether resin (B). The amino group may be primary, secondary, or tertiary, but is preferably a primary amino group.

[0072] The polyether resin (B) may have one or more reactive groups, but more preferably has only one reactive group. If the polyether resin (B) has two or more reactive groups, a three-dimensional network structure may form when it is bonded to the polyolefin (A), which may result in gelation.

[0073] However, even if it has multiple reactive groups, it is sufficient that there is only one reactive group that is more reactive than the others. For example, a polyether resin (B) having multiple hydroxyl groups and one amino group that is more reactive than the others is a preferred example. Here, reactivity refers to reactivity with the reactive groups of the polyolefin (A).

[0074] A suitable polyether resin (B) is a block copolymer of a polyether block having an alkylene group with 2 carbon atoms and a polyether block having an alkylene group with 3 to 4 carbon atoms. Two or more types of polyether blocks having an alkylene group with 3 to 4 carbon atoms may be contained in the block copolymer, provided that the effects of the present invention are not significantly impaired.

[0075] A more suitable polyether resin (B) is represented by the following general formula (1).

[0076] [ka]

[0077] In the general formula (1), X is an alkylene group having 3 to 4 carbon atoms, and Y is an alkylene group having 2 carbon atoms. R is a hydrogen atom, an amino group, or an alkyl group having 1 to 3 carbon atoms. n is preferably 1 to 40, and m is preferably 1 to 30.

[0078] The polyether resin (B) preferably has an HLB value of 1 to 20 as calculated by the Griffin method.

[0079] The weight average molecular weight [Mw] of the polyether resin (B) is preferably 200 to 200,000. The weight average molecular weight [Mw] of the polyether resin (B) is a value measured by GPC and converted using a polystyrene calibration curve.

[0080] The lower limit of Mw is more preferably 300, and even more preferably 500. The upper limit of Mw is more preferably 100,000, and even more preferably 10,000, and especially preferably 3,000. The higher the Mw, the lower the surface energy of the resin dispersion, and the better the wettability tends to be, whereas the lower the Mw, the lower the viscosity, and the easier it is to prepare the resin dispersion. GPC measurement is carried out by a conventional method using a commercially available device and THF as a solvent.

[0081] [Polymer (C)] The polymer (C) in which a polyether resin (B) is bonded to a polyolefin (A) may be a graft copolymer in which a polyether resin (B) is graft-bonded to a polyolefin (A), or a block copolymer of a polyolefin (A) and a polyether resin (B) in which a polyether resin (B) is bonded to one or both ends of a polyolefin (A); The former graft copolymer is preferred.

[0082] A graft copolymer in which a polyether resin (B) is graft-bonded to a polyolefin (A) has the advantage that the content of the polyether resin (B) can be easily controlled and the content of the polyether resin (B) can be increased more easily than in a block copolymer.

[0083] The polyether resin (B) can be bonded to the polyolefin (A) by various reaction methods. The reaction methods are not particularly limited, but examples thereof include a radical graft reaction and a reaction using a reactive group. In the radical graft reaction, a carbon-carbon covalent bond is formed.

[0084] The reaction utilizing reactive groups involves reacting the reactive groups present in both the polyolefin (A) and the polyether resin (B) to form a covalent or ionic bond. Examples of such reactions include the esterification reaction of a carboxylic acid group with a hydroxyl group, the ring-opening reaction of a carboxylic acid group with an epoxy group, the ring-opening reaction of a primary or secondary amino group with an epoxy group, the amidation reaction of a carboxylic acid group with a primary or secondary amino group, the quaternary ammonium reaction of a carboxylic acid group with a tertiary amino group, the urethane reaction of a carboxylic acid group with an isocyanate group, and the urethane reaction of a primary or secondary amino group with an isocyanate group.

[0085] The reaction rate of each reaction may be selected arbitrarily from 1 to 100%, preferably from 50 to 100%, and more preferably from 70 to 100%. When the carboxylic acid group is a dibasic acid or an anhydride thereof, one or two equivalents of the carboxylic acid group may be reacted with one equivalent of the dibasic acid or anhydride thereof.

[0086] The method for producing the polymer (C) by bonding the polyolefin (A) and the polyether resin (B) is usually either a method (R1) in which a hydrophilic monomer is polymerized in the presence of the polyolefin (A) to form the polyether resin (B) bonded to the polyolefin (A), or a method (R2) in which a prepolymerized polyether resin (B) is bonded to the polyolefin (A). In either case, the polyolefin (A) may be either a polyolefin (A1) having no reactive groups or a polyolefin (A2) having reactive groups.

[0087] (Production method (R1) of polymer (C)) In the production method (R1), a hydrophilic monomer that forms a polyether resin (B) is polymerized in the presence of a polyolefin (A) to obtain a polyether resin (B) bonded to the polyolefin (A). Examples of polymerization methods for the hydrophilic monomer include addition polymerization, condensation polymerization, and ring-opening polymerization. In this case, a hydrophobic monomer may be copolymerized within a range that allows the formation of a polyether resin (B) after polymerization.

[0088] For example, there is a method in which a hydrophilic radically polymerizable unsaturated compound is polymerized in the presence of a radical polymerization initiator to form a polyether resin (B) and then bonded to a polyolefin (A). In this case, a polyolefin (A2) having a reactive group can be used as the polyolefin (A), but a polyolefin (A1) having no reactive group is usually used.

[0089] The hydrophilic radical polymerizable unsaturated compound is not particularly limited, and examples thereof include (meth)acrylic acid, hydroxyethyl (meth)acrylate, methoxypolyethylene glycol (meth)acrylate, dimethylaminoethyl (meth)acrylate, quaternized dimethylaminoethyl (meth)acrylate, and vinylpyrrolidone. Examples of copolymerizable hydrophobic monomers include (meth)acrylic acid esters such as methyl (meth)acrylate and butyl (meth)acrylate, and vinyl acetate.

[0090] Another method is to polymerize a radically polymerizable unsaturated compound in the presence of a radical polymerization initiator to form a polymer and bond it to a polyolefin (A), which is then modified to form a polyether resin (B). For example, there is a method in which t-butyl (meth)acrylate is polymerized, then hydrolyzed under acidic conditions to modify it into poly(meth)acrylic acid, and a method in which vinyl acetate is polymerized, then saponified to modify it into polyvinyl alcohol.

[0091] Examples of copolymerizable hydrophobic monomers include (meth)acrylic acid esters such as methyl (meth)acrylate and butyl (meth)acrylate, and vinyl acetate. In this case, a polyolefin (A2) having a reactive group can also be used as the polyolefin (A), but a polyolefin (A1) having no reactive group is usually used.

[0092] Another example is a method in which a polyolefin (A2) having a reactive group is used, and a hydrophilic radical polymerizable unsaturated compound or a hydrophilic ring-opening polymerization monomer is polymerized using the reactive group as an initiation terminal to obtain a polyether resin (B). As the hydrophilic radical polymerizable unsaturated compound, the same compounds as those described above can be used.

[0093] Examples of hydrophilic ring-opening polymerization monomers include ethylene oxide and ethyleneimine. Examples of copolymerizable hydrophobic monomers include trimethylene oxide, tetrahydrofuran, β-propiolactone, γ-butyrolactone, and ε-caprolactone. These may be used alone or in combination of two or more.

[0094] The reaction method is not particularly limited as long as it can produce the polymer (C), and any method may be used, including, for example, a method of reacting by heating and stirring in a solution, a method of reacting by melting and heating and stirring in the absence of a solvent, and a method of reacting by heating and kneading in an extruder.

[0095] The reaction temperature is usually in the range of 0 to 200° C., and preferably in the range of 30 to 150° C. When producing in solution, the solvents that can be used are the same as those exemplified as the solvents used in the production of polyolefin (A1).

[0096] (Production method (R2) of polymer (C)) In the production method (R2), a prepolymerized polyether resin (B) is bonded to the polyolefin (A). In this case, the polyether resin (B) may be any of those listed above in the description of the polyether resin (B).

[0097] Specifically, for example, a method can be mentioned in which an unsaturated double bond is left in the molecule when a hydrophilic monomer is polymerized to form a polyether resin, and then the unsaturated double bond is graft-polymerized onto the polyolefin (A) using a radical polymerization initiator. In this case, a polyolefin (A2) having a reactive group can also be used as the polyolefin (A), but a polyolefin (A1) having no reactive group is usually used.

[0098] Another method is to first prepare a polyether resin (B) having a reactive group at its terminal, and then bond this to a polyolefin (A2) having a reactive group. A polyether resin having a reactive group at its terminal can be obtained by polymerizing a hydrophilic monomer using a compound having a reactive group as an initiator or chain transfer agent. Alternatively, it can be obtained by ring-opening polymerization of a hydrophilic ring-opening polymerization monomer such as an epoxy compound.

[0099] As the hydrophilic monomer, the various hydrophilic monomers listed in the section (Production method (R1) of polymer (C)) can be used. Each of these may be used alone or in combination of two or more.

[0100] The reaction method is not particularly limited as long as it can produce a polymer (C) that satisfies the requirements of the present invention, and any method may be used. Examples include a method of reacting by heating and stirring in a solution, a method of reacting by melting and heating and stirring in the absence of a solvent, and a method of reacting by heating and kneading in an extruder.

[0101] The reaction temperature is usually in the range of 0 to 200° C., and preferably in the range of 30 to 150° C. When producing in solution, the solvents that can be used are the same as those exemplified as the solvents used in the production of polyolefin (A1).

[0102] The polymer (C) produced by the above method can be determined by the following method to be a bond between polyolefin (A) and polyether resin (B), and the polyether resin (B) contains polyether resin (B1) having an HLB of less than 8 as calculated by the Griffin method and polyether resin (B2) having an HLB of 8 to 20.

[0103] A more detailed explanation follows: After dissolving the polymer (C) in a solvent such as toluene, benzene, or xylene, sodium hydroxide and water are added and the mixture is stirred at 80 to 100°C to cause a hydrolysis reaction, dissociating the polyether resin (B) from the polymer (C). Next, the polyolefin (A) obtained after dissociating the polyether resin (B) from the polymer (C) is removed by reprecipitation using a solvent such as acetone, methyl ethyl ketone, diethyl ketone, or methyl isobutyl ketone.

[0104] A method for separating the polyether resin (B) into the polyether resin (B1) and the polyether resin (B2) includes, for example, fractionating the polyether resin (B1) and the polyether resin (B2) by reverse phase liquid chromatography and isolating each of the resins. The analytical conditions can be appropriately determined by a person skilled in the art.

[0105] The structures of the polyether resins (B1) and (B2) can be determined and the HLB values ​​calculated by the Griffin method can be calculated as follows: That is, the molecular weight and structural units are detected and measured using mass spectrometry, 1 H-NMR and C 13 The structures are detected and measured using NMR, and the structures of the polyether resin (B1) and the polyether resin (B2) are identified based on these.

[0106] (Amount of polyether resin (B) bound) In the polymer (C), the polyolefin (A) and the polyether resin (B) are preferably bonded in a weight ratio of polyolefin (A):polyether resin (B) = 100:1 to 100:100. This weight ratio is more preferably 100:5 to 100:70, and even more preferably 100:10 to 100:50. By keeping the weight ratio within this range, it is easy to obtain a stable resin dispersion with good hydrophilicity and a small dispersed particle size, and adhesion to polyolefin substrates also tends to be improved.

[0107] The amount of polyether resin (B1) bonded to polyolefin (A) is preferably in the range of 1 to 50 parts by weight per 100 parts by weight of polyolefin (A). The lower limit of the amount of polyether resin (B1) bonded is more preferably 3 parts by weight, and particularly preferably 5 parts by weight. The upper limit is more preferably 45 parts by weight, and even more preferably 40 parts by weight.

[0108] The higher the bonding amount of polyether resin (B1) is from the lower limit, the lower the surface energy of the resin dispersion and the better the wettability tends to be. The lower the bonding amount is from the upper limit, the higher the stability of the aqueous resin dispersion tends to be.

[0109] The amount of polyether resin (B2) bonded to polyolefin (A) is preferably in the range of 1 to 50 parts by weight per 100 parts by weight of polyolefin (A). The lower limit of the amount of polyether resin (B2) bonded is more preferably 2 parts by weight, and particularly preferably 4 parts by weight. The upper limit is more preferably 30 parts by weight, and even more preferably 20 parts by weight.

[0110] The higher the bound amount of polyether resin (B2) is from the lower limit, the more hydrophilic the dispersed particles become, the smaller the particle size becomes, and the more stable the dispersion tends to be. Conversely, the lower the bound amount is from the upper limit, the more the adhesion to the crystalline polyolefin substrate tends to increase.

[0111] In order to more effectively obtain the effect of including both polyether resin (B1) and polyether resin (B2) as polyether resin (B), the proportion of polyether resin (B1) relative to the polyether resin (B) bonded to polyolefin (A), i.e., the total of polyether resin (B1) and polyether resin (B2), is preferably 1 to 95% by weight, and particularly preferably 10 to 90% by weight.

[0112] The polyether resin (B1) and the polyether resin (B2) preferably have an HLB difference of 8 or more, and particularly preferably have a difference of about 12 to 16.

[0113] [Nucleating Agent (E)] Examples of the crystal nucleating agent (E) include organic nucleating agents and inorganic nucleating agents. Examples of the organic nucleating agent include metal salts of benzoic acid or its derivatives in which an alkyl group is substituted with an aromatic ring, such as aluminum salt of pt-butylbenzoate, dibenzylidene sorbitol and its derivatives, such as 1,3,2,4-dibenzylidene sorbitol, 1,3,2,4-di(p-methylbenzylidene) sorbitol, 1,3,2,4-di(p-chlorobenzylidene) sorbitol, 1,3,2,4-di(p-methoxybenzylidene) sorbitol, and organic acid salts such as sodium bis(4-t-butylphenyl) phosphate, calcium oxalate, magnesium stearate, zinc salicylate, and calcium tartrate. Examples of inorganic nucleating agents include clays such as talc, clay, mica, montmorillonite, and bentonite, and metal oxides such as calcium silicate, magnesium silicate, calcium sulfate, barium sulfate, calcium carbonate, titanium oxide, magnesium carbonate, and zinc oxide. Among these, organic nucleating agents are preferred, and sorbitols are more preferred. Dibenzylidene sorbitol and its derivatives are even more preferred.

[0114] The amount of the nucleating agent (E) is preferably 0.01 to 10% by weight based on the weight of the polyolefin (A) from the viewpoints of adhesion to the polyolefin substrate and production stability, and more preferably 0.1 to 1.0% by weight from the viewpoints of adhesion to the polyolefin substrate and production stability.

[0115] [Composition (I)] In the resin dispersion of the present invention, a composition (I) containing a polyolefin (A) and a crystal nucleating agent (E) is dispersed in a dispersion medium. The polyolefin (A) and the crystal nucleating agent (E) may be dispersed together or separately. When preparing the emulsion, the polyolefin (A) and the crystal nucleating agent (E) may be dispersed simultaneously, or dispersions in which the polyolefin (A) and the crystal nucleating agent (E) are separately dispersed in advance may be mixed.

[0116] The melting point of composition (I) is 20 to 120° C., preferably 50 to 100° C., and particularly preferably 70 to 80° C. If it is within the above range, excellent adhesion to polyolefin substrates is achieved. The melting point of composition (I) is measured by a differential scanning calorimeter (DSC) method.

[0117] The crystallization temperature of composition (I) is 20 to 100° C., preferably 20 to 60° C., and particularly preferably 30 to 40° C. Within the above range, excellent adhesion to polyolefin substrates is achieved. The crystallization temperature of composition (I) is measured by a differential scanning calorimeter (DSC) method.

[0118] The dispersion of the present invention is a dispersion of the composition (I) in a dispersion medium. The solvent used as the dispersion medium will be described later.

[0119] [Resin dispersion] The method for producing the resin dispersion of the present invention is not particularly limited, but examples thereof include a method in which a nucleating agent (E) is added during the production of the polyolefin (A) described above, and a method in which the polyolefin (A) and the nucleating agent (E) are melted at a temperature higher than the melting point and then a dispersion medium is added to form a dispersion. Another example is a method in which the polyolefin (A) and the nucleating agent (E) dissolved in a solvent are mixed. The former method is preferred.

[0120] A resin dispersion having fine particle sizes can be easily prepared by adding a solvent to the polyolefin (A), dissolving the polyolefin (A) by heating as necessary, and then adding water. The temperature at which the polyolefin (A) is dissolved in or added to the solvent is usually 30 to 150°C.

[0121] Alternatively, the polyolefin (A) may be dissolved in a solvent, and the solvent may be distilled off to replace the solvent. The final ratio of water to the total solvent in the resin dispersion is usually 50% by weight or less, preferably 20% by weight or less, more preferably 10% by weight or less, and particularly preferably 1% by weight or less.

[0122] Examples of solvents other than water include aromatic hydrocarbons such as toluene, xylene, and t-butylbenzene; aliphatic hydrocarbons such as hexane, octane, and decane; alicyclic aliphatic hydrocarbons such as cyclohexane and methylcyclohexane; halogenated hydrocarbons such as methylene chloride, carbon tetrachloride, and chlorobenzene; esters such as methyl acetate, ethyl acetate, propyl acetate, and butyl acetate; ketones such as acetone, methyl ethyl ketone, methyl propyl ketone, methyl isobutyl ketone, and cyclohexanone; alcohols such as methanol, ethanol, n-propanol, isopropanol, n-butanol, 2-butanol, isobutanol, t-butanol, cyclohexanol, ethylene glycol, propylene glycol, and butanediol; ethers such as dipropyl ether, dibutyl ether, and tetrahydrofuran; organic solvents having two or more functional groups such as 2-methoxyethanol, 2-ethoxyethanol, 2-butoxyethanol, 2-methoxypropanol, 2-ethoxypropanol, and diacetone alcohol; and polar solvents such as dimethylformamide and dimethyl sulfoxide. These may be used alone or in combination of two or more.

[0123] Among these, solvents that dissolve in water at 1% by weight or more are preferred, and more preferably at 5% by weight or more. For example, methyl ethyl ketone, cyclohexanone, n-propanol, isopropanol, n-butanol, 2-butanol, isobutanol, t-butanol, cyclohexanol, tetrahydrofuran, 2-methoxyethanol, 2-ethoxyethanol, 2-butoxyethanol, 2-methoxypropanol, and 2-ethoxypropanol are preferred.

[0124] The apparatus for producing the resin dispersion by dissolving the polyolefin (A) in a solvent or melting it and then adding water is not particularly limited, but examples include a reaction vessel equipped with a stirrer, a single-screw or twin-screw kneader, etc. The stirring speed in this case varies slightly depending on the type of apparatus selected, but is usually in the range of 10 to 1000 rpm.

[0125] The polyolefin (A) (resin) used in the present invention has excellent dispersibility in water, and therefore, a resin dispersion of polyolefin (A) has the advantage that the dispersed particles have a small diameter and the resin is stably dispersed. Using such a resin dispersion of the present invention, a coated article with excellent appearance can be obtained.

[0126] The dispersed particle diameter of the polyolefin (A) in the resin dispersion of the present invention is usually 50% particle diameter D 50 The 50% particle diameter D 50 The particle size of the polyolefin (A) can be set to 0.5 μm or less, and more preferably 0.3 μm or less. By reducing the dispersed particle size of the polyolefin (A), the dispersion stability can be improved, aggregation is less likely to occur, and a more stable resin dispersion can be obtained.

[0127] In the present invention, the term "dispersion" refers to a state in which the dispersed particles are extremely small and dispersed as monomolecules, which can be said to be essentially dissolved. Therefore, there is no particular restriction on the lower limit of the dispersed particle diameter.

[0128] The solid content of the resin dispersion of the present invention is preferably 5% by weight or more, more preferably 10% by weight or more, and even more preferably 20% by weight or more. It is also preferably 70% by weight or less, more preferably 60% by weight or less, and even more preferably 50% by weight or less. The lower the solid content, the higher the stability of the resin dispersion tends to be. However, when used as a primer or adhesive, for example, a higher solid content is preferred in order to avoid the need for a large amount of energy and time for drying water after application.

[0129] As described above, the polyolefin (A) used in the present invention allows a resin dispersion to be obtained substantially without using a surfactant, and therefore, one of the advantages of the aqueous resin composition obtained using this is that it can suppress the bleed-out that has conventionally been caused by surfactants.

[0130] However, the resin dispersion of the present invention may contain a surfactant as needed depending on other purposes, applications, etc. Examples of surfactants include cationic surfactants, anionic surfactants, nonionic surfactants, amphoteric surfactants, and reactive surfactants.

[0131] Examples of nonionic surfactants include polyoxyethylene cetyl ether, polyoxyethylene stearyl ether, polyoxyethylene nonylphenyl ether, and polyoxyethylene sorbitan monolaurate.

[0132] Examples of anionic surfactants include sodium dodecylbenzenesulfonate, sodium sulfosuccinate, sodium lauryl sulfate, and sodium polyoxyethylene lauryl sulfate ether.

[0133] Examples of cationic surfactants include stearyltrimethylammonium chloride and cetyltrimethylammonium bromide, etc. Examples of amphoteric surfactants include lauryldimethylaminoacetate betaine, etc.

[0134] In addition, so-called reactive surfactants having a radical polymerizable functional group can be used as the surfactants, and when a reactive surfactant is used, the water resistance of the coating film can be improved. Typical commercially available reactive surfactants include Eleminol JS-2 (manufactured by Sanyo Chemical Industries, Ltd.) and Latemul S-180 (manufactured by Kao Corporation).

[0135] When the resin dispersion of the present invention contains a surfactant, the content of the surfactant is usually preferably 20 parts by weight or less, more preferably 10 parts by weight or less, and even more preferably 5 parts by weight or less, based on 100 parts by weight of the polymer (C). Most preferably, the resin dispersion is substantially free of surfactant.

[0136] The resin dispersion of the present invention may contain water as a dispersion medium and / or solvent, but may further contain other dispersion mediums and / or solvents.

[0137] The other dispersion medium and / or solvent is not particularly limited, and one or more of the solvents listed as solvents other than water when producing the aqueous dispersion of polyolefin (A) can be used. Among them, a solvent that dissolves in water at 5% by weight or more is preferred, and more preferably at 10% by weight or more.

[0138] For example, cyclohexanone, n-propanol, isopropanol, n-butanol, 2-butanol, t-butanol, tetrahydrofuran, 2-methoxyethanol, 2-ethoxyethanol, 2-butoxyethanol, 2-methoxypropanol, and 2-ethoxypropanol are preferred.

[0139] For example, when the resin dispersion of the present invention is used for applications such as primers, paints, or inks, a hydrophilic organic solvent other than water can be blended therein for the purpose of improving the drying speed or obtaining a surface with a good finish. Examples of hydrophilic organic solvents include alcohols such as methanol and ethanol, ketones such as acetone, glycols such as ethylene glycol and propylene glycol, and ethers thereof.

[0140] The proportion of other dispersion mediums and / or solvents in the dispersion medium and / or solvent containing water is usually 50% by weight or less, preferably 30% by weight or less, and more preferably 20% by weight or less.

[0141] If necessary, an acidic or basic substance can be added to the resin dispersion of the present invention. Examples of acidic substances include inorganic acids such as hydrochloric acid and sulfuric acid, and organic acids such as acetic acid. Examples of basic substances include inorganic bases such as sodium hydroxide and potassium hydroxide, ammonia, triethylamine, diethylamine, dimethylethanolamine, 2-methyl-2-aminopropanol, and triethanolamine.

[0142] For example, it is preferable to add a basic substance when the polyolefin (A) has an acidic group, and to add an acidic substance when the polyolefin (A) has a basic group. Doing so has the advantage of increasing the hydrophilicity of the polyolefin (A) and making the dispersed particle size smaller.

[0143] The resin dispersion of the present invention may contain various additives as needed, provided that the effects of the present invention are not significantly impaired. For example, various additives may be blended and used, such as ultraviolet absorbers, antioxidants, various stabilizers such as weathering stabilizers and heat resistance inhibitors, colorants such as dyes, organic pigments and inorganic pigments, conductivity imparting agents such as carbon black and ferrite, pigment dispersants, leveling agents, antifoaming agents, thickeners, preservatives, mildew inhibitors, rust inhibitors, and wetting agents. Such additives that exist in a solid state in the resin dispersion at room temperature are included in composition (I).

[0144] Examples of the antifoaming agent include "Surfynol 104PA" and "Surfynol 440" manufactured by Air Products Co., Ltd.

[0145] To further improve various coating film properties such as water resistance and solvent resistance, a crosslinking agent can be added in an amount of 0.01 to 100 parts by weight per 100 parts by weight of the polyolefin (A) in the resin dispersion. Examples of crosslinking agents include self-crosslinking agents, compounds having multiple functional groups intrinsic to the molecule that react with carboxylic acid groups, and metal complexes having polyvalent coordination sites.

[0146] Among these, preferred are isocyanate compounds, melamine compounds, urea compounds, epoxy compounds, carbodiimide compounds, oxazoline group-containing compounds, zirconium salt compounds, and silane coupling agents. These crosslinking agents may also be used in combination.

[0147] The resin dispersion of the present invention may optionally contain a water-dispersible resin other than the water-soluble resin or polyolefin (A) within a range that does not significantly impair the effects of the present invention, and the incorporation of such other resins can provide effects such as improving the appearance of the coating (gloss or matte finish) or reducing tackiness. The resin may be a resin that can be dispersed using a surfactant.

[0148] As the water-soluble resin, for example, the resins listed as the polyether resin (B) can be used, and for example, an aqueous solution of such a resin dissolved in water can be mixed with the resin dispersion of the present invention and used.

[0149] Examples of resins that can be dispersed in water include acrylic resins, polyester resins, polyurethane resins, epoxy resins, vinyl ester resins, melamine resins, and alkyd resins. The form of the resin dispersion containing these resins and polyolefin (A) is not particularly limited. For example, there is a method in which these resins and polyolefin (A) are emulsified and mixed together. In this method, particles made of these resins and particles made of polyolefin (A) are separately formed, and a resin dispersion dispersed in water is obtained.

[0150] Alternatively, there is a method of mixing these resins with polyolefin (A) and then emulsifying the mixture. This method produces a resin dispersion in which particles in which the resin and polyolefin (A) are mixed together are dispersed in water. For example, the two can be mixed by having polyolefin (A) coexist during the polymerization of the resin, and the mixture can be emulsified and dispersed in water to form particles containing the resin and polyolefin (A) in each particle.

[0151] The resin and polyolefin (A) can also be synthesized separately and then mixed by melt-kneading or the like, and then emulsified and dispersed in water to form particles containing the resin and polyolefin (A) within each particle.

[0152] In order to effectively utilize the properties of the polyolefin (A) and the resin, a resin dispersion in which particles of the polyolefin (A) and particles of the resin are present separately is preferred. Such a resin dispersion can be obtained, for example, by mixing a dispersion obtained by emulsifying and dispersing the polyolefin (A) in water with a dispersion obtained by emulsifying and dispersing the resin in water.

[0153] When other resins are mixed, the weight ratio of the total amount of polyolefin (A) and the other resins to water is preferably 5:95 to 60:40. That is, the total amount of polyolefin (A) and the other resins is preferably 5 parts by weight or more and 60 parts by weight or less, where the total amount of polyolefin (A), the other resins, and water is 100 parts by weight.

[0154] By setting this ratio to 5 parts by weight or more, workability in application, heat curing, etc. is improved. Preferably, it is set to 10 parts by weight or more, more preferably 15 parts by weight or more. On the other hand, by setting this ratio to 60 parts by weight or less, it is possible to prevent the viscosity of the resin dispersion from becoming too high, improving application properties and facilitating the formation of a uniform coating film. Preferably, it is set to 55 parts by weight or less, more preferably 50 parts by weight or less.

[0155] The weight ratio of the polyolefin (A) to the other resins is preferably 90:10 to 10:90. That is, the amount of the polyolefin (A) is preferably 10 parts by weight or more and 90 parts by weight or less, where the total amount of the polyolefin (A) and the other resins is 100 parts by weight.

[0156] By using 10 parts by weight or more of polyolefin (A), sufficient adhesion to polyolefin substrates can be achieved. The amount of polyolefin (A) is preferably 15 parts by weight or more, more preferably 20 parts by weight or more.

[0157] By setting the amount of polyolefin (A) to 90 parts by weight or less, the effect of using other resins in combination can be fully obtained, and the physical properties of the coating film obtained from such a composite resin dispersion, specifically, the coating film strength, water resistance, weather resistance, abrasion resistance, solvent resistance, etc. can be fully improved. The amount of polyolefin (A) is preferably 85 parts by weight or less, more preferably 80 parts by weight or less.

[0158] The polyolefin (A) can be isolated from the resin dispersion of the present invention, for example, by the following method. Specifically, a solvent such as toluene, hexane, or benzene is added dropwise to the resin dispersion, followed by stirring at 60 to 80°C to dissolve the polyolefin (A) in the solvent. The solvent in which the polyolefin (A) is dissolved is then subjected to oil phase separation. A solvent such as acetone, methyl ethyl ketone, diethyl ketone, or methyl isobutyl ketone is added to the resulting solution to reprecipitate and isolate the polyolefin (A).

[0159] A pigment can be added to the resin dispersion of the present invention, and the resin dispersion containing a pigment is preferable as a paint.

[0160] Usable pigments are not particularly limited, but examples include inorganic pigments such as titanium oxide, carbon black, iron oxide, chromium oxide, Prussian blue, red iron oxide, yellow lead, and yellow iron oxide, as well as organic pigments such as azo pigments, anthracene pigments, perinone pigments, perylene pigments, quinacridone pigments, isoindolinone pigments, indigo pigments, and phthalocyanine pigments; extender pigments such as talc, calcium carbonate, clay, kaolin, silica, and precipitated barium sulfate; conductive pigments such as whiskers coated with conductive carbon or antimony-doped tin oxide; and uncolored or colored metallic luster materials such as metals, alloys, or metal oxides, such as aluminum, copper, zinc, nickel, tin, or aluminum oxide. These pigments may be used alone or in combination of two or more.

[0161] When the resin dispersion of the present invention contains a pigment, the content of the pigment is preferably 10 parts by weight or more, more preferably 50 parts by weight or more, per 100 parts by weight of the resin (total amount of polyolefin (A) and other resins used as needed). However, it is preferably 400 parts by weight or less, more preferably 200 parts by weight or less. The color development and hiding power tend to be higher when the amount of pigment added is greater than the above lower limit, and the adhesion, moisture resistance, and oil resistance tend to be higher when the amount is less than the above upper limit.

[0162] When the above-mentioned polyolefin (A) is used as the polymer (C), a resin dispersion can be obtained in the same manner.

[0163] When the resin dispersion of the present invention contains a pigment, a pigment dispersant may be used. Examples of pigment dispersants include aqueous acrylic resins such as Joncryl Resin manufactured by Johnson Polymer; acidic block copolymers such as BYK-190 manufactured by BYK-Chemie; styrene-maleic acid copolymers; acetylene diol derivatives such as Surfynol T324 manufactured by Air Products; and water-soluble carboxymethyl acetate butyrates such as CMCAB-641-0.5 manufactured by Eastman Chemical Company. The use of these pigment dispersants allows the preparation of a stable pigment paste.

[0164] The resin dispersion of the present invention can be used for primers, primerless paints, adhesives, inks, etc. The present invention is particularly suitable for use as a primer, paint, or adhesive, and is particularly suitable for use as a primer, paint, or adhesive for polyolefin substrates. Specific applications include, for example, automotive paints for interior and exterior use, primers, paints for home appliances such as mobile phones and personal computers, and paints for building materials.

[0165] [Laminate] The resin layer can be formed by applying the resin dispersion of the present invention or a coating material containing the same to a substrate and then heating the coating film. The laminate comprises a substrate and a resin layer provided on the surface of the substrate.

[0166] The substrate of the laminate is preferably a thermoplastic resin molded article. The thermoplastic resin molded article is not particularly limited, but examples thereof include polyolefin resin, polyamide resin, polyethylene terephthalate resin, polybutylene terephthalate resin, unsaturated polyester resin, and polycarbonate resin. In particular, it is preferably applied to a thermoplastic resin molded article made of a polyolefin resin, and particularly preferably to a thermoplastic resin molded article made of a propylene-based polymer.

[0167] Examples of the olefin polymer used as the substrate include olefin polymers such as high-pressure polyethylene, medium-low pressure polyethylene, polypropylene, poly-4-methyl-1-pentene, poly-1-butene, and polystyrene, as well as olefin copolymers such as ethylene-propylene copolymer, ethylene-butene copolymer, and propylene-butene copolymer, etc. Furthermore, the substrate may also be a molded article made of polypropylene and synthetic rubber, for example.

[0168] The shape of the substrate is not particularly limited, and examples thereof include films, sheets, plates, and other irregular shapes.

[0169] The substrate to which the resin dispersion of the present invention or a coating material containing the same is applied may be molded by any known molding method such as injection molding, compression molding, blow molding, extrusion molding, or rotational molding.

[0170] The resin dispersion of the present invention or a paint containing the same can form a coating film with good adhesion even when the substrate contains inorganic fillers such as talc, zinc oxide, glass fiber, titanium dioxide, or magnesium sulfate, or pigments.

[0171] The method for forming a resin layer on a substrate using the resin dispersion of the present invention or a coating material containing the same is not particularly limited, and known methods can be used. Examples of coating methods include spray coating, bar coating, spin coating, dip coating (immersion coating), and gravure coating. Generally, large molded articles such as automobile bumpers or home appliances are coated by spray coating. Furthermore, plastic films or sheets are coated by gravure coating or bar coating.

[0172] After applying the resin dispersion of the present invention or a coating material containing the same to a substrate, the coating film is typically cured by heating with a nichrome wire, infrared radiation, or high frequency radiation, thereby obtaining a laminate having a desired coating film on its surface. The curing conditions for the coating film are appropriately selected depending on the material or shape of the substrate or the composition of the coating material used. There are no particular restrictions on the curing temperature, but in consideration of practicality, it is typically 50°C or higher, preferably 60°C or higher. However, it is typically 150°C or lower, preferably 130°C or lower.

[0173] The thickness of the resin layer to be laminated (after curing) is appropriately selected depending on the material or shape of the substrate, the composition of the coating material used, or the application of the laminate, but is usually 0.1 μm or more, preferably 1 μm or more, and more preferably 5 μm or more, but is usually 500 μm or less, preferably 300 μm or less, more preferably 200 μm or less, and particularly preferably 100 μm or less.

[0174] The laminate of the present invention can be used in various industrial parts, such as automobiles, home appliances, and building materials, and has sufficient performance for practical use, particularly as thin-walled, highly functional, or large-sized parts and materials. For example, it can be used as a molding material for various industrial parts, such as automobile parts such as bumpers, instrument panels, trim, and garnishes, home appliance parts such as television cases, washing machine tubs, refrigerator parts, air conditioner parts, and vacuum cleaner parts, toiletry parts such as toilet seats, toilet seat lids, and water tanks, and bathroom parts such as bathtubs, bathroom walls, ceilings, and drain pans. [Example]

[0175] Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited to the following description.

[0176] [Measurement and Evaluation of Composition (I)] (Melting point of composition (I)) Measurement was carried out using a differential scanning calorimeter DSC6200 manufactured by Seiko Instruments Inc. according to the following measurement method. Measurement method: A sample (composition (I), approximately 3 to 5 mg) was weighed and placed in a dedicated aluminum pan. After melting the sample at 200°C, the temperature was lowered to 0°C at a rate of 10°C / min, and then raised to 200°C at a rate of 10°C / min to obtain a melting curve. The peak top temperature of the main endothermic peak in the final heating stage was measured as the melting point.

[0177] (Crystallization temperature of composition (I)) Measurement was carried out using a differential scanning calorimeter DSC6200 manufactured by Seiko Instruments Inc. according to the following measurement method. Measurement method: A sample (composition (I), approximately 3 to 5 mg) was weighed and placed in a dedicated aluminum pan. The sample was heated from room temperature to 150°C at a rate of 5°C / min, and then cooled to -20°C at a rate of -2°C / min to obtain a melting curve. The peak top temperature of the main exothermic peak during the cooling stage was measured as the crystallization temperature.

[0178] (Weight average molecular weight of polyolefin (A)) The olefin resin dispersion was vacuum-dried at 40°C for 12 hours and then measured using a GPC system (Tosoh Corporation, HLC-8320). A 0.4% by mass solution of the olefin resin in THF was prepared, and 100 μL of the solution was injected into the system equipped with a Tosoh Corporation column (TSKgel G5000HXL, GMHXL-L, TSKguardcolumnHXL-H). Measurement was performed under conditions of a flow rate of 1 mL / min, eluent: THF (stabilizers: BHT, citric acid 1 mM added), and column temperature: 40°C, and the weight-average molecular weight (Mw) was calculated in terms of standard polystyrene.

[0179] [Evaluation of resin dispersion] (Test piece preparation) The surface of a substrate made from Japan Polypropylene's "TSOP-6" (3 mm thick, 70 mm wide, and 100 mm long) was wiped clean with isopropyl alcohol. The resulting resin dispersion was spray-coated onto the substrate to a dry film thickness of 20 μm, and after setting at room temperature for 10 minutes, it was dried in a Safebend dryer at 80°C and 120°C for 35 minutes to form a coating.

[0180] (Adhesion to substrate) Next, 11 cuts were made in the coating surface of the test piece at 1 mm intervals in both the vertical and horizontal directions so as to reach the substrate, creating 100 grids. Cellophane adhesive tape was then applied to the grids, and the condition of the coating was observed after the adhesive tape was quickly peeled off, and the water-resistant adhesion was evaluated according to the following evaluation criteria. Evaluation criteria: ○: 100 squares remain out of 100 squares. △: 90 to 99 squares remain out of 100 squares. ×: Fewer than 90 squares remain out of 100.

[0181] (water resistance) The resulting coating was immersed in 60°C warm water for one day to obtain a test piece. 30 minutes after immersion, the test piece was removed and 11 incisions were made in each direction, 1 mm apart, lengthwise and widthwise, reaching the substrate, creating 100 grids. Cellophane adhesive tape was then applied to the grids, and the tape was then quickly peeled off. The condition of the coating was observed and the water-resistant adhesion was evaluated according to the following criteria. Evaluation criteria: ○: 100 squares remain out of 100 squares. △: 90 to 99 squares remain out of 100 squares. ×: Fewer than 90 squares remain out of 100.

[0182] (peel strength) Approximately 1 cm of masking tape was applied to one edge of a 3 mm thick, 150 mm wide, and 100 mm long "polypropylene" substrate manufactured by Taiyu Kizai Co., Ltd. and a "TSOP-6" substrate manufactured by Japan Polypropylene Corporation to prevent the water-based paint from being applied, and the surface of the substrate was then wiped clean with isopropyl alcohol. Next, the water-based paint was sprayed onto the test piece so that the film thickness after drying would be 10 μm, and the test piece was dried in a Safebend dryer at 80°C for 5 minutes, after which the masking tape was peeled off.

[0183] Next, the resulting test pieces were spray-coated with a two-component polyurethane paint to a dry thickness of 100 μm. The coated test pieces were then dried in a Safebend dryer at 80°C and 120°C for 30 minutes. The coated test pieces were then left at 25°C for at least 24 hours to cure the two-component polyurethane paint. A 150 mm wide, 220 mm long piece of craft tape was attached to the cured two-component polyurethane coating, with the water-based paint coating at the longitudinal edge of the tape and the tape extending beyond the edge of the non-water-based paint coating. A 1.5 cm wide cut was made vertically through the craft tape and the coating with a cutter.

[0184] Using a small bench-top tensile tester EZ-S500S manufactured by Shimadzu Corporation, the protruding end of the craft tape with the cut was clamped in one jig and the substrate part at the opposite end in the other jig, and the average peel strength was measured when pulled 50 mm in the 180° direction at a pulling speed of 50 mm / min, and the peel strength was converted to per 1 cm.

[0185] [Example 1] (Preparation of Composition (I-1)) Preparation of polyolefin A2 containing reactive groups: 200 kg of Tafmer (registered trademark) XM-7070 (trade name, manufactured by Mitsui Chemicals, Inc., melting point: 75°C, propylene content: 74 mol%, weight average molecular weight (Mw): 250,000 (polypropylene equivalent), molecular weight distribution (Mw / Mn): 2.2), a propylene-butene copolymer (corresponding to an olefin polymer) polymerized using a metallocene catalyst, and 5 kg of maleic anhydride were dry-blended in a super mixer. Thereafter, using a twin-screw extruder (trade name: TEX54αII, manufactured by The Japan Steel Works, Ltd.), t-butylperoxyisopropyl monocarbonate (polymerization initiator, trade name: Perbutyl® I, manufactured by NOF Corporation) was added in an amount of 1 part by mass per 100 parts by mass of the propylene-butene copolymer using a liquid addition pump. The mixture was kneaded under conditions of a kneading section cylinder temperature of 200°C, a screw rotation speed of 125 rpm, and a discharge rate of 80 kg / hour, to obtain a pellet-shaped maleic anhydride-modified propylene-butene copolymer (graft polymer (A12b)). The physical properties of the obtained maleic anhydride-modified propylene-butene copolymer are shown below. Maleic anhydride group content (grafting rate): 1.0 mass% (0.1 mmol / g as maleic anhydride group, 0.2 mmol / g as carboxylic acid group) Weight average molecular weight (Mw): 156,000 (polystyrene equivalent) Number average molecular weight (Mn): 84,000

[0186] A 2 L glass flask equipped with a bottom-drawing valve and an oil-circulating jacket heater was equipped with a nitrogen gas inlet tube, a reflux condenser, a thermometer, and a stirrer. Then, 100 g of "Tafmer XM-5070" (Mitsui Chemicals, Inc., melting point 70 °C, propylene content 70 mol%, weight average molecular weight [Mw] 250,000 (polypropylene equivalent)), a propylene-butene copolymer (A1) polymerized with a metallocene catalyst, 150 g of the reactive group-containing polyolefin (A2) obtained above, 0.25 g of the crystal nucleating agent (E) "Gelall D," and 166.5 g of toluene were added. The atmosphere in the vessel was purged with nitrogen gas, and the temperature was raised to 110 °C. After the temperature was raised, 3.75 g of maleic anhydride and 1.88 g of t-butylperoxyisopropyl monocarbonate (NOF Corporation, "Perbutyl I") were added, and the reaction was continued with stirring at the same temperature for 7 hours.

[0187] After the reaction was completed, the system was cooled to around 70°C, and 178.5 g of toluene was added. Then, 50 g of polyetheramine (trade name "JEFFAMINE M-2005") (number average molecular weight 2000) dissolved in 325 g of 2-propanol was added dropwise to the flask over 1 hour at 70°C, and the mixture was allowed to react for another 1 hour at 70°C. Thereafter, 25 g of polyetheramine (trade name "JEFFAMINE M-1000", number average molecular weight 1000) dissolved in 175 g of 2-propanol was added dropwise over 1 hour at 70°C, and the mixture was allowed to react for another 1 hour at 70°C. Subsequently, 3.75 g of dimethylethanolamine, 112.5 g of 2-propanol, and 155 g of water were added to neutralize the system. The temperature of the resulting reaction solution was maintained at 50°C, and while heating and stirring, 905 g of water was added dropwise. The degree of vacuum in the system was reduced, and toluene and 2-propanol were distilled off under reduced pressure until the polymer concentration reached 30% by mass, yielding an aqueous resin dispersion with an average particle size of 88 nm.

[0188] [Examples 2-5, Comparative Example 1] An aqueous resin dispersion was obtained in the same manner as in Example 1, except that the type and amount of the nucleating agent (E) used in the above-mentioned production example of the polyolefin (A) composition (I-1) was changed as shown in Table 1.

[0189] [Example 6] (Preparation of Composition (I-2)) A 2 L glass flask equipped with a bottom-drawing valve and an oil-circulating jacket heater was equipped with a nitrogen gas inlet tube, a reflux condenser, a thermometer, and a stirrer. Then, 100 g of "Tafmer XM-5070" (Mitsui Chemicals, Inc., melting point 70 °C, propylene content 70 mol%, weight-average molecular weight [Mw] 250,000 (polypropylene equivalent)), a propylene-butene copolymer (A1) polymerized with a metallocene catalyst, 100 g of a polyolefin (A2) having reactive groups, 0.2 g of a nucleating agent (E) "Gelall D," and 300 g of toluene were added. The atmosphere in the vessel was purged with nitrogen gas, and the temperature was raised to 110 °C. After the temperature was raised, 3.0 g of maleic anhydride and 1.0 g of t-butylperoxyisopropyl monocarbonate (NOF Corporation, "Perbutyl I") were added, and the reaction was continued with stirring at the same temperature for 7 hours.

[0190] After the reaction was completed, the mixture was cooled to around 70°C, 96 g of toluene was added, and then 1620 g of 70°C hot water was added and stirred for 30 minutes. After standing, the mixture separated into two phases, and 1548 g of the lower phase (aqueous phase) was removed from the bottom of the flask. 1.5 g of maleic anhydride was then added to the flask, and 40 g of polyetheramine (trade name "Jeffamine M-2005") (number average molecular weight 1000) dissolved in 480 g of 2-propanol was added dropwise at 70°C over 1 hour, and the mixture was allowed to react at 70°C for another 1 hour. Thereafter, 300 g of water was added. The temperature of the resulting reaction liquid was maintained at 50°C, and while heating and stirring, 600 g of water was added dropwise, and the degree of vacuum in the system was reduced, and toluene and 2-propanol were distilled off under reduced pressure until the polymer concentration reached 30% by mass, yielding an aqueous resin dispersion with an average particle size of 93 nm.

[0191] [Examples 7 and 8] An aqueous resin dispersion was obtained in the same manner as in Example 6, except that the type and amount of the nucleating agent (E) used in the above-mentioned production example of the polyolefin (A) composition (I-2) was changed as shown in Table 1.

[0192] 70.1 g of the resulting aqueous resin dispersion, 21.6 g of white pigment (WT-9004 manufactured by Nippon Pigment), 2.5 g of TEGO WET KL-245 (manufactured by EVONIK), and 5.9 g of water were mixed at 500 rpm for 10 minutes and filtered through a 150 μm nylon mesh to obtain a water-based paint. The resulting water-based paint was used to evaluate adhesion, peel strength, and water resistance to a "polypropylene" substrate manufactured by Taiyu Kizai Co., Ltd. and a "TSOP-6" substrate manufactured by Japan Polypropylene Corporation.

[0193] [Example 9] An aqueous resin dispersion was obtained without adding the crystal nucleating agent (E) used in the above-mentioned production example of composition (I-2) of polyolefin (A). 60.5 g of the resulting aqueous resin dispersion, 18.6 g of white pigment (WT-9004 manufactured by Nippon Pigment), 2.1 g of TEGO WET KL-245 (manufactured by EVONIK), and 0.041 g of the nucleating agent (E) "Gelall D" (listed in Table 1) dissolved in 5.9 g of water and 13.6 g of 2-propanol were mixed in a disperser at 500 rpm for 10 minutes. The mixture was filtered through a 150 μm nylon mesh to obtain an aqueous paint. The resulting aqueous paint was used to evaluate adhesion, peel strength, and water resistance to a "polypropylene" substrate manufactured by Taiyu Kizai Co., Ltd. and a "TSOP-6" substrate manufactured by Japan Polypropylene Corporation.

[0194] [Table 1]

[0195] The meanings of the terms in Table 1 are as follows: Gelall D (nucleating agent for polyolefins, manufactured by New Japan Chemical Co., Ltd.) Gelall MD (nucleating agent for polyolefins, manufactured by New Japan Chemical Co., Ltd.) Gelall DXR (nucleating agent for polyolefins, manufactured by New Japan Chemical Co., Ltd.)

[0196] The adhesiveness, water resistance, and peel strength were excellent in Examples 1 to 10. In contrast, the adhesiveness was insufficient in Comparative Example 1, which used a composition that did not contain the crystal nucleating agent (E). [Industrial Applicability]

[0197] The resin dispersion of the present invention can be produced substantially without using conventional surfactants, has good adhesion to polyolefin substrates, and can be easily applied without any limitation on the application method, so that the resin dispersion of the present invention is useful as a paint, primer, ink, adhesive, etc.

Claims

1. A resin dispersion comprising a composition (I) containing a polyolefin (A) and a crystal nucleating agent (E).

2. The resin dispersion according to claim 1, wherein the melting point of the composition (I) is 20 to 120°C.

3. 2. The resin dispersion according to claim 1, wherein the crystallization temperature of the composition (I) is 20 to 100°C.

4. 2. The resin dispersion according to claim 1, wherein the polyolefin (A) is a homopolymer of propylene or a copolymer of propylene and another comonomer.

5. The resin dispersion according to claim 1, wherein the polyolefin (A) is a copolymer of propylene and butene.

6. The resin dispersion according to claim 1 , wherein the polyolefin (A) is a polyolefin (A1) having a reactive group.

7. 2. The resin dispersion according to claim 1, wherein the content of the crystal nucleating agent (E) is 0.01 to 10 parts by mass per 100 parts by mass of the polyolefin (A).

8. The resin dispersion according to claim 1 , wherein the crystal nucleating agent (E) is a sorbitol.

9. The resin dispersion according to claim 1 , which is an aqueous resin dispersion in which at least the polyolefin (A) is dispersed in water.

10. A paint comprising the resin dispersion according to any one of claims 1 to 9.

11. An adhesive comprising the resin dispersion according to any one of claims 1 to 9.

12. A substrate and a resin layer provided on a surface of the substrate, A laminate, wherein the resin layer is formed by heating a coating film of the resin dispersion according to any one of claims 1 to 9.

13. A substrate and a resin layer provided on a surface of the substrate, A laminate, wherein the resin layer is formed by heating a coating film of the paint according to claim 10.

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