Resin for aqueous dispersions and coating film using same

Abstract

This resin for aqueous dispersions contains an ionomer that is characterized in that at least a portion of the carboxyl groups and / or dicarboxylic anhydride groups in a substantially linear copolymer (P) containing, as essential constituent units, a structural unit (A) derived from ethylene and / or C3-20 α-olefin and a structural unit (B) derived from a monomer having a carboxyl group and / or a dicarboxylic anhydride group, has been converted into the metal-containing carboxylate containing at least one metal ion selected from group 1, group 2, or group 12 of the Periodic Table. It is thereby possible to provide a homogeneous and stable aqueous dispersion which exhibits excellent physical properties when a coating film is formed, particularly an excellent abrasion resistance, heat resistance, and strength.

Description

Resin for aqueous dispersions and coating film using the same

[0001] This invention relates to a resin for aqueous dispersions using a novel ethylene-based ionomer, and a coating film using the same.

[0002] Ethylene-based ionomers are resins that use ethylene-unsaturated carboxylic acid copolymers as a base resin, with intermolecular bonds formed by metal ions such as sodium and zinc (Patent Document 1). They are tough, highly elastic, flexible, and possess characteristics such as abrasion resistance and transparency. Currently, commercially available ethylene-based ionomers include "Surlyn®," a sodium and zinc salt of ethylene-methacrylic acid copolymer developed by DuPont, and "Hymiran®," sold by Mitsui-Dow Polychemicals.

[0003] The ethylene-unsaturated carboxylic acid copolymers used as base resins in these currently commercially available ethylene-based ionsomers all utilize polar group-containing olefin copolymers, which are polymerized by high-pressure radical polymerization of ethylene and polar group-containing monomers such as unsaturated carboxylic acids. High-pressure radical polymerization has the advantage of being able to polymerize relatively inexpensively without being limited by the type of polar group-containing monomer. However, the molecular structure of polar group-containing olefin copolymers produced by high-pressure radical polymerization has the disadvantage of being a highly branched molecular structure with many irregular long-chain and short-chain branches, as shown in the image diagram in Figure 1, and is therefore insufficient in terms of strength.

[0004] On the other hand, methods for producing polar group-containing olefin copolymers with a linear molecular structure, as shown in the image diagram in Figure 2, using a catalyst polymerization method have been sought. Polar group-containing monomers are generally catalyst poisons, making polymerization difficult, and in fact, it has long been difficult to obtain polar group-containing olefin copolymers with desired physical properties in an industrially inexpensive and stable manner. However, in recent years, a method for obtaining polar group-containing olefin copolymers with a substantially linear molecular structure has been proposed using a new catalyst and new manufacturing method developed by the applicants of this application (Patent Document 2). Patent Document 2 reports that a copolymer of ethylene and t-butyl acrylate is produced using a late-period transition metal catalyst, the obtained polar group-containing olefin copolymer is modified into an ethylene-acrylic acid copolymer by heat or acid treatment, and then reacted with metal ions to produce a binary ionomer.

[0005] Thermoplastic resins containing ethylene-based ionomers are easy to mold into desired shapes to manufacture articles due to their plasticity, and can be applied to various molding methods from a molten state, such as mold molding using a mold, extrusion molding to form a film, and blow molding to create hollow containers by inflating with air. Another known method of applying thermoplastic resins is to use polymers dissolved in a liquid medium. Solutions containing polymer particles are homogeneous and suitable for forming thin films, and are widely used for coating substrates and other applications. Conventionally, organic solvents capable of dissolving polymers were used as the medium, but from the perspective of environmental impact, such as the diffusion of organic solvents into the atmosphere during film formation, there is a growing trend to replace them with aqueous dispersions. Many thermoplastic resins are insoluble or sparingly soluble in water, but moldability is maintained by uniformly dispersing polymer particles in the medium. Reports of aqueous dispersions of ionomers have also been made (Patent Documents 3 and 4).

[0006] U.S. Patent No. 3264272 Specification JP 2016-79408 JP 11-263848 JP Special Publication No. 2014-525509

[0007] In aqueous polymer dispersions, it is necessary to be able to stably maintain a state in which polymer particles are uniformly dispersed in the medium, and there is always a demand for more homogeneous and stable dispersions. Furthermore, when used as a coating film, although the required degree differs depending on the application, generally, adhesion, strength, abrasion resistance, rigidity, and heat resistance are required. Depending on the application, high transparency of the coating film is also important. However, with conventional polyethylene resins containing ionomers, it has been difficult to obtain one of these physical properties that is dramatically improved, or a combination that satisfies them sufficiently. Ethylene-based ionomers with a highly branched molecular structure do not have sufficient resistance to impact in the range from room temperature to low temperatures, and as the inventors have found, they are unsuitable for coating film applications where abrasion and pinhole formation due to contact with other objects must be avoided. In view of the situation of the prior art, this application aims to provide a homogeneous and stable aqueous dispersion with excellent physical properties when forming a coating film, particularly abrasion resistance, heat resistance, and strength.

[0008] To solve the above problems, the inventors conducted extensive research and found that a specific ionomer resin has a remarkably superior effect on the physical properties required for aqueous dispersions and coating films using them. This ethylene-based ionomer is a novel ethylene-based ionomer in which the base resin has a substantially linear molecular structure and also functions as an ionomer. Its physical properties are expected to differ significantly from conventional ethylene-based ionomers with a highly branched molecular structure. However, due to the lack of established means for stably supplying large quantities of the resin, the resin's inherent properties and suitability for various applications remained unknown. This invention is based on the discovery that a resin containing a substantially linear ethylene-based ionomer has a superior effect on providing a homogeneous and stable aqueous dispersion and improving the physical properties required for coating films.

[0009] In other words, the present invention is as shown in [1] to [9] below. [1] A resin for aqueous dispersions comprising an ionomer obtained by converting at least a portion of the carboxyl group and / or dicarboxylic acid anhydride group in a copolymer (P) that satisfies the following conditions (a) and (b) into a metal-containing carboxylate salt containing at least one metal ion selected from Group 1, Group 2, or Group 12 of the periodic table. (a) １３ (b) The number of methyl branches calculated by C-NMR is 50 or less per 1,000 carbon atoms. (b) The absolute value G of the complex modulus measured with a rotational rheometer. ＊ [1] The aqueous dispersion resin according to [1], characterized in that the copolymer (P) contains 2.0 to 20.0 mol% of structural unit (B) in the copolymer, wherein the phase angle δ at 0.1 MPa is 50 to 75 degrees. [2] The aqueous dispersion resin according to [1] or [2], characterized in that the structural unit (A) is a structural unit derived from ethylene. [4] The aqueous dispersion resin according to any one of [1] to [3], characterized in that the copolymer (P) is produced using a transition metal catalyst containing a transition metal of groups 8 to 11 of the periodic table. [5] The aqueous dispersion resin according to [4], characterized in that the transition metal catalyst is a transition metal catalyst consisting of a phosphorusulfonic acid or phosphorphenol ligand and nickel or palladium. [6] The aqueous dispersion resin according to any one of [1] to [5], characterized in that the melt flow rate of the copolymer (P), measured at a temperature of 190°C and a load of 2.16 kg, is 10 to 5000 g / 10 min. [7] An aqueous dispersion comprising the aqueous dispersion resin described in any of [1] to [6] above and water. [8] A method for producing an aqueous dispersion, comprising the step of mixing the aqueous dispersion resin described in any of [1] to [6] above with water and stirring at a temperature of 50°C to 250°C. [9] A coating film formed using the aqueous dispersion described in [7] above.

[0010] The aqueous dispersion of the present invention, which uses an ionomer having a substantially linear structure, can provide a stable and homogeneous dispersion compared to aqueous dispersions obtained from existing polyethylene or ionomer resins having a multi-branched structure, and exhibits superior physical properties during coating film formation, particularly in terms of abrasion resistance, heat resistance, and strength.

[0011] This is a conceptual diagram of the branched molecular structure of a polar group-containing olefin copolymer produced by high-pressure radical polymerization. The circles in the diagram represent polar groups. This is a conceptual diagram of a linear polar group-containing olefin copolymer. The circles in the diagram represent polar groups.

[0012] The present invention is an aqueous dispersion containing an ionomer, characterized in that a copolymer (P) is used as a base resin, obtained by substantially copolymerizing, preferably randomly copolymerizing, a structural unit (A) derived from ethylene and / or an α-olefin having 3 to 20 carbon atoms and a structural unit (B) derived from a monomer having a carboxyl group and / or a dicarboxylic acid anhydride group in a linear manner, and at least a portion of the carboxyl group and / or dicarboxylic acid anhydride group of the structural unit (B) is converted into a metal-containing carboxylate salt containing at least one metal ion selected from Group 1, Group 2, or Group 12 of the periodic table.

[0013] The following describes in detail, item by item, the ionomers, aqueous dispersions using the ionomers, and their applications related to the present invention. In this specification, "(meth)acrylic acid" means acrylic acid or methacrylic acid. In this specification, "~" indicating a numerical range is used to mean that the values ​​written before and after it are included as the lower and upper limits. In this specification, copolymer means a binary or more copolymer comprising at least one unit (A) and at least one unit (B). In this specification, ionomer means a binary or more copolymer ionomer comprising the structural unit (A) and a structural unit (B') in which at least a part of the structural unit (B) is converted to a metal-containing carboxylate salt, and which may further contain the structural unit (B).

[0014] 1. Ionomer The ionomer of the present invention is characterized in that it has structural units (A) derived from ethylene and / or α-olefins having 3 to 20 carbon atoms and structural units (B) derived from monomers having carboxyl groups and / or dicarboxylic acid anhydride groups as essential constituent units, and optionally includes structural units (C) which are compounds having one or more carbon-carbon double bonds in their molecular structure, and these are copolymerized substantially in a linear manner, preferably randomly copolymerized, to form a copolymer (P) as the base resin, and at least a portion of the carboxyl groups and / or dicarboxylic acid anhydride groups of structural unit (B) are converted into a metal-containing carboxylate salt containing at least one metal ion selected from Group 1, Group 2, or Group 12 of the periodic table.

[0015] (1) Structural unit (A) Structural unit (A) is at least one structural unit selected from the group consisting of structural units derived from ethylene and structural units derived from α-olefins having 3 to 20 carbon atoms. The α-olefin related to the present invention has the structural formula CH ２ =CHR １８ It is an α-olefin having 3 to 20 carbon atoms, represented by (R １８ (The carbon group is a hydrocarbon group having 1 to 18 carbon atoms, and may have a linear or branched structure.) The carbon number of the α-olefin is more preferably 3 to 12.

[0016] Specific examples of structural unit (A) include ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-decene, 3-methyl-1-butene, and 4-methyl-1-pentene, and may also be ethylene. As for ethylene, in addition to ethylene derived from petroleum raw materials, ethylene derived from non-petroleum raw materials such as plant raw materials can be used. Furthermore, structural unit (A) may be one type or multiple types. Examples of combinations of two types include ethylene-propylene, ethylene-1-butene, ethylene-1-hexene, ethylene-1-octene, propylene-1-butene, propylene-1-hexene, and propylene-1-octene. Examples of combinations of the three include ethylene-propylene-1-butene, ethylene-propylene-1-hexene, ethylene-propylene-1-octene, propylene-1-butene-hexene, and propylene-1-butene-1-octene.

[0017] In the present invention, structural unit (A) preferably contains ethylene as an essential component, and may further contain one or more α-olefins having 3 to 20 carbon atoms as needed. The amount of ethylene in structural unit (A) may be 65 to 100 mol%, or 70 to 100 mol%, relative to the total moles of structural unit (A). From the viewpoint of impact resistance, the above structural unit (A) may consist only of structural units derived from ethylene.

[0018] (2) Structural Unit (B) Structural unit (B) is a structural unit derived from a monomer having a carboxyl group and / or a dicarboxylic acid anhydride group. Note that structural unit (B) has the same structure as a structural unit derived from a monomer having a carboxyl group and / or a dicarboxylic acid anhydride group, and as described in the manufacturing method below, it does not necessarily have to be manufactured using a monomer having a carboxyl group and / or a dicarboxylic acid anhydride group.

[0019] Examples of structural units derived from monomers having a carboxyl group include unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, fumaric acid, tetrahydrophthalic acid, itaconic acid, citraconic acid, crotonic acid, isocrotonic acid, norbornenedicarboxylic acid, and bicyclo[2,2,1]hept-2-ene-5,6-dicarboxylic acid. Examples of structural units derived from monomers having a dicarboxylic acid anhydride group include maleic anhydride, itaconic anhydride, citraconic anhydride, tetrahydrophthalic anhydride, 5-norbornene-2,3-dicarboxylic acid anhydride, 3,6-epoxy-1,2,3,6-tetrahydrophthalic anhydride, and tetracyclo[6.2.1.1 3,6 . 0 2,7 Examples include unsaturated dicarboxylic acid anhydrides such as dodeca-9-ene-4,5-dicarboxylic acid anhydride and 2,7-octadiene-1-ylsuccinic acid anhydride. As structural units derived from monomers having a carboxyl group and / or dicarboxylic acid anhydride group, acrylic acid, methacrylic acid, and 5-norbornene-2,3-dicarboxylic acid anhydride are preferred from the viewpoint of ease of industrial availability, and acrylic acid may be particularly preferred. Furthermore, there may be one type or more types of structural units derived from monomers having a carboxyl group and / or dicarboxylic acid anhydride group.

[0020] In addition, the dicarboxylic acid anhydride group may react with moisture in the air to open its ring, and a portion of it may become a dicarboxylic acid. However, the dicarboxylic acid anhydride group may remain ring-open as long as it does not depart from the spirit of the present invention.

[0021] (3) Other Structural Unit (C) As the copolymer (P) used in the present invention, a binary copolymer composed only of the structural unit (A) and the structural unit (B), and a copolymer composed of the structural unit (A), the structural unit (B), and optionally, other structural units (C) can be used. However, it may be a copolymer further containing a structural unit (C) other than the structural units represented by the structural unit (A) and the structural unit (B). The monomer that provides the structural unit (C) can be any monomer as long as it is not included in the monomers that provide the structural unit (A) and the structural unit (B). The monomer that provides the structural unit (C) is not limited as long as it is a compound having one or more carbon-carbon double bonds in its molecular structure. Examples include acyclic monomers represented by the general formula (1) shown below and cyclic monomers represented by the general formula (2). By using a terpolymer or higher copolymer containing the structural unit (C) component as the base resin of the ionomer, an ionomer with a lower melting point and crystallinity than the binary copolymer tends to be obtained. An ionomer with a low crystallinity is excellent in transparency when formed into a coating film, and thus is suitable for applications where the visibility of the substrate is required. Although the copolymer has a tendency to have a lower melting point than the binary copolymer, it is sufficient to exhibit the heat resistance required for coating film applications. The structural unit (C) may be based on one type of monomer, or two or more types of monomers may be used in combination.

[0022] - Acyclic Monomer [In General Formula (1), T １ to T ３ are each independently a substituent selected from the group consisting of a hydrogen atom, a hydrocarbon group having 1 to 20 carbon atoms, a hydrocarbon group having 1 to 20 carbon atoms substituted with a hydroxyl group, a hydrocarbon group having 2 to 20 carbon atoms substituted with an alkoxy group having 1 to 20 carbon atoms, a hydrocarbon group having 3 to 20 carbon atoms substituted with an ester group having 2 to 20 carbon atoms, a hydrocarbon group having 1 to 20 carbon atoms substituted with a halogen atom, an alkoxy group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, an ester group having 2 to 20 carbon atoms, a silyl group having 3 to 20 carbon atoms, a halogen atom, or a cyano group. T ４This substituent is selected from the group consisting of a hydroxyl group-substituted C1-C20 hydrocarbon group, a C2-C20 hydrocarbon group-substituted C1-C20 alkoxy group, a C3-C20 hydrocarbon group-substituted C2-C20 ester group, a halogen atom-substituted C1-C20 hydrocarbon group, a C1-C20 alkoxy group, a C6-C20 aryl group, a C2-C20 ester group, a C3-C20 silyl group, a halogen atom, or a cyano group.

[0023] In the ionomer of the present invention, T １ and T 2 T may be a hydrogen atom, ３ T may be a hydrogen atom or a methyl group. ４ This may be an ester group having 2 to 20 carbon atoms.

[0024] T １ ~T ４ The carbon skeletons of the hydrocarbon groups, substituted alkoxy groups, substituted ester groups, alkoxy groups, aryl groups, ester groups, and silyl groups may have branching, rings, and / or unsaturated bonds. １ ~T ４ The number of carbon atoms in the hydrocarbon group related to this can be 1 or more at the lower limit, 20 or less at the upper limit, or 10 or less. １ ~T ４ The number of carbon atoms in the substituted alkoxy group may be 1 or more at the lower limit, 20 or less at the upper limit, or 10 or less. １ ~T ４ The number of carbon atoms in the substituted ester group may be 2 or more at the lower limit and 20 or less at the upper limit, or 10 or less. １ ~T ４ The number of carbon atoms in the alkoxy group related to this can be 1 or more at the lower limit, 20 or less at the upper limit, or 10 or less. １ ~T ４ The number of carbon atoms in the aryl group can be 6 or more at the lower limit, 20 or less at the upper limit, or 11 or less. １ ~T ４The number of carbon atoms in the ester group can be 2 or more at the lower limit, 20 or less at the upper limit, or 10 or less. １ ~T ４ The number of carbon atoms in the silyl group can be 3 or more at the lower limit and 18 or less at the upper limit, or 12 or less. Examples of silyl groups include trimethylsilyl, triethylsilyl, tri-n-propylsilyl, triisopropylsilyl, dimethylphenylsilyl, methyldiphenylsilyl, and triphenylsilyl.

[0025] In the ionomer of the present invention, in terms of ease of manufacture, T １ and T 2 T may be a hydrogen atom, ３ T may be a hydrogen atom or a methyl group. １ ~T ３ However, all of them may be hydrogen atoms. Also, from the viewpoint of impact resistance, T ４ This may be an ester group having 2 to 20 carbon atoms.

[0026] Examples of acyclic monomers include (meth)acrylic acid esters, etc. ４ Examples include cases where the group has 2 to 20 carbon atoms. ４ When the group is an ester group with 2 to 20 carbon atoms, the acyclic monomer is: Structural formula: CH ２ = C(R ２１ ) CO ２ (R ２２ Examples of compounds represented by ) are shown here. ２１ R is a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms, and may have branching, rings, and / or unsaturated bonds. ２２ R is a hydrocarbon group having 1 to 20 carbon atoms, and may have branching, rings, and / or unsaturated bonds. ２２ It may contain heteroatoms at any position within the structure. Structural formula: CH ２ = C(R ２１ ) CO ２ (R ２２ As a compound represented by ), R ２１ However, examples include compounds that are hydrogen atoms or hydrocarbon groups having 1 to 5 carbon atoms. Also, R２１ Acrylic acid ester or R, where is a hydrogen atom ２１ Examples include methacrylate esters, which have a methyl group. Structural formula: CH ２ = C(R ２１ ) CO ２ (R ２２ Specific examples of compounds represented by ) include, for example, methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, cyclohexyl (meth)acrylate, octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, nonyl (meth)acrylate, decyl (meth)acrylate, dodecyl (meth)acrylate, octadecyl (meth)acrylate, phenyl (meth)acrylate, toluyl (meth)acrylate, and benzyl (meth)acrylate. Specific examples of compounds include methyl acrylate, ethyl acrylate, n-butyl acrylate (nBA), isobutyl acrylate (iBA), t-butyl acrylate (tBA), and 2-ethylhexyl acrylate, with n-butyl acrylate (nBA), isobutyl acrylate (iBA), and t-butyl acrylate (tBA) being particularly suitable. The acyclic monomer may be one type or multiple types.

[0027] ・Cyclic monomer [In general formula (2), R １ ~R １２ These may be the same or different, and are selected from the group consisting of hydrogen atoms, halogen atoms, and hydrocarbon groups having 1 to 20 carbon atoms, R ９ and R １０ , and also, R １１ and R １２ These may each integrate to form a divalent organic group, R ９ or R １０ And, R １１ or R １２These may form a ring with each other. Also, n represents 0 or a positive integer, preferably n is 0, 1 or 2, more preferably n is 0, and if n is 2 or more, R ５ ~R ８ These elements may be identical or different within each repeating unit.

[0028] Examples of cyclic monomers include norbornene-based olefins, such as norbornene, vinylnorbornene, ethylidenenorbornene, norbornadiene, tetracyclododecene, and tricyclo[4.3.0.1 ２，５ Examples include compounds having a cyclic olefin skeleton such as deca-3-ene, 2-norbornene (NB), and tetracyclo[6.2.1.1 ３，６ . 0 ２，７ Dodeca-4-en may also be used.

[0029] (4) Copolymer (P) The copolymer (P) that forms the base resin of the ionomer used in the present invention contains structural units (A) derived from ethylene and / or α-olefins having 3 to 20 carbon atoms and structural units (B) derived from monomers having carboxyl groups and / or dicarboxylic acid anhydride groups as essential constituent units, and optionally contains arbitrary structural units (C) other than (A) and (B), and each of these structural units is copolymerized substantially linearly, preferably randomly copolymerized. "Substantially linear" means that the copolymer does not have branching or the frequency of branching structures is small, and the copolymer can be considered linear. Specifically, it means that the following conditions (a) and (b) are satisfied. (a) １３ (b) The number of methyl branches calculated by C-NMR is 50 or less per 1,000 carbon atoms. (b) The absolute value G of the complex modulus measured with a rotational rheometer. ＊ = The phase angle δ at 0.1 MPa is between 50 and 75 degrees.

[0030] (a) Number of methyl branches per 1,000 carbon atoms of the copolymer: Copolymer (P) is chosen because it has a high elastic modulus and provides sufficient mechanical properties even when it forms a coating film. １３The number of methyl branches calculated by C-NMR has an upper limit of 50 or less per 1,000 carbon atoms, may be 5 or less, 1 or less, or 0.5 or less, and there is no particular lower limit; the fewer the better. Similarly, the number of ethyl branches has an upper limit of 3.0 or less per 1,000 carbon atoms, may be 2.0 or less, 1.0 or less, or 0.5 or less, and there is no particular lower limit; the fewer the better. Furthermore, the number of butyl branches has an upper limit of 7.0 or less per 1,000 carbon atoms, may be 5.0 or less, 3.0 or less, or 0.5 or less, and there is no particular lower limit; the fewer the better. The cause of methyl branching in polymer chains is the same as the cause of long-chain branching, and polymers without long-chain branching will have fewer methyl branches.

[0031] The number of methyl branches per 1,000 carbon atoms in the copolymer (P) is: １３ It is determined using C-NMR spectroscopy. １３ ¹¹C-NMR is measured by the following method: 200-300 mg of the sample is mixed with o-dichlorobenzene (¹¹C). ６ H ４ Cl ２ ) and deuterated bromide benzene (C ６ D ５ Mixed solvent of Br (C ６ H ４ Cl ２ / C ６ D ５ 2.4 ml of Br (2 / 1 by volume) and hexamethyldisiloxane, the reference substance for chemical shift, are placed in a 10 mm diameter NMR sample tube, purged with nitrogen, sealed, and heated to dissolve into a homogeneous solution, which is then used as the NMR measurement sample. NMR measurement is performed at 120°C using a Bruker Japan AV400M NMR spectrometer equipped with a 10 mm diameter cryoprobe. １３ ¹³C-NMR is measured using the reverse gate decoupling method with a sample temperature of 120°C, a pulse angle of 90°, a pulse interval of 51.5 seconds, and a total of 512 or more integration cycles. The chemical shift is that of hexamethyldisiloxane. １３ Set the C signal to 1.98 ppm, and the other１３ The chemical shift of the signal by C is used as a reference. The obtained １３ In 13C-NMR, the signals specific to the monomers or branches possessed by the copolymer can be identified, and by comparing their intensities, the number of branches can be analyzed. The positions of the signals specific to the monomers or branches can be referred to known materials, or can be identified independently according to the sample. Such an analysis method can generally be carried out by those skilled in the art.

[0032] (b) Absolute value G of complex elastic modulus ＊ = Phase angle δ at 0.1 MPa: In the copolymer (P) of the present invention, the absolute value G of the complex elastic modulus measured by a rotational rheometer ＊ = The phase angle δ at 0.1 MPa is characterized by being 50 to 75 degrees. The lower limit of the phase angle δ may be 50 degrees or more, 51 degrees or more, 54 degrees or more, 56 degrees or more, 58 degrees or more, and the upper limit of the phase angle δ may be 75 degrees or less, 70 degrees or less. More specifically, the absolute value G of the complex elastic modulus measured by a rotational rheometer ＊ = Phase angle δ at 0.1 MPa (G ＊ = 0.1 MPa) is 50 degrees or more, the molecular structure of the copolymer is a linear structure, a structure that does not contain any long-chain branches, or a structure that contains a small amount of long-chain branches that does not affect the mechanical strength. In this specification, "long-chain branch" refers to a branched chain existing on the polymer main chain, which has a length greater than that which can be regarded as a carbon chain of about 1,200 in terms of molecular weight although it is not an absolute standard. Also, "short-chain branch" does not refer to the counterpart of the long-chain branch, but refers to a branch that has a size such that even if it exists, the molecular rheological properties of the polymer chain can be regarded as the same as those of a completely linear molecule. This is also not an absolute standard, but if it has a size similar to that of a carbon chain with 40 or less carbon atoms, such as the functional group of a comonomer grafted onto the polymer main chain, it can be classified as a short-chain branch. Also, the absolute value G of the complex elastic modulus measured by a rotational rheometer ＊ = Phase angle δ at 0.1 MPa (G ＊When the temperature (0.1 MPa) is lower than 50 degrees, the molecular structure of the copolymer shows a structure containing excessive long-chain branches, resulting in inferior mechanical strength. The absolute value G of the complex elastic modulus measured by a rotational rheometer ＊ The phase angle δ at 0.1 MPa is affected by both the molecular weight distribution and the long-chain branches. However, only for copolymers with Mw / Mn ≤ 4, more preferably Mw / Mn ≤ 3, it becomes an index of the amount of long-chain branches. The more long-chain branches contained in the molecular structure, the smaller the δ (G ＊ = 0.1 MPa) value. If the Mw / Mn of the copolymer is 1.5 or more, even when the molecular structure does not contain long-chain branches, the δ (G ＊ = 0.1 MPa) value does not exceed 75 degrees.

[0033] The method for measuring the complex elastic modulus is as follows. Put the sample into a heating press mold with a thickness of 1.0 mm, preheat it in a hot press machine with a surface temperature of 180 °C for 5 minutes, then degas the residual gas in the molten resin by repeating pressurization and depressurization, and further pressurize it at 4.9 MPa and hold for 5 minutes. Then, transfer the sample to a press machine with a surface temperature of 25 °C, cool it by holding at a pressure of 4.9 MPa for 3 minutes, and create a press plate composed of a sample with a thickness of about 1.0 mm. Use a sample obtained by processing the press plate made of the sample into a 25 mm diameter circle, and use an ARIS type rotational rheometer manufactured by Rheometrics as a measuring device for dynamic viscoelastic properties, and measure the dynamic viscoelasticity under the following conditions in a nitrogen atmosphere. - Plate: φ25 mm parallel plate - Temperature: 160 °C - Strain amount: 10% - Measurement angular frequency range: 1.0 × 10 －２ ~1.0 × 10 ２ rad / s - Measurement interval: 5 points / decade The absolute value G of the complex elastic modulus ＊ (Pa) of the common logarithm logG ＊ Plot the phase angle δ against logG ＊ = 5.0, and take the value of δ (degrees) at the point corresponding to logG ＊ = 0.1 MPa as δ (G ＊ = 5.0. When there is no point corresponding to logG ＊ = 5.0 among the measurement points, use two points around logG ＊The δ value at =5.0 is determined by linear interpolation. Also, all measurement points are log G. ＊ <When it is 5, logG ＊ Using the three largest values, plot log G using a quadratic curve. ＊ The δ value at =5.0 is obtained by extrapolation.

[0034] • Molecular structure of copolymer (P): The molecular chain ends of copolymer (P) may be structural units (A) of ethylene and / or α-olefins having 3 to 20 carbon atoms, structural units (B) of monomers having a carboxyl group and / or a dicarboxylic acid anhydride group, or any structural unit (C) other than (A) and (B).

[0035] Furthermore, the copolymer (P) can be a random copolymer, block copolymer, or graft copolymer of ethylene and / or α-olefin structural units having 3 to 20 carbon atoms (A), monomer structural units having a carboxyl group and / or a dicarboxylic acid anhydride group (B), and any monomer structural units (C). Among these, a random copolymer that can contain a large amount of structural unit (B) is also possible. A random copolymer is a copolymer in which the probability of finding each structural unit derived from each monomer at any given position in a molecular chain constituting the copolymer is independent of the type of adjacent structural units.

[0036] The random copolymerizability of copolymers (P) can be confirmed by various methods, but a method for determining random copolymerizability from the relationship between the comonomer content and melting point of copolymers (P) is described in detail in Japanese Patent Publication No. 2015-163691 and Japanese Patent Publication No. 2016-079408. From the above documents, it can be determined that the randomness is low if the melting point (Tm, °C) of the copolymer is higher than -3.74 × [Z] + 130 (where [Z] is the comonomer content / mol%).

[0037] In the present invention, which is a random copolymer, it is preferable that the melting point (Tm, °C) observed by differential scanning calorimetry (DSC) and the total content [Z] (mol%) of monomer structural units (B) having a carboxyl group and / or dicarboxylic acid anhydride group and structural units (C) of any monomer satisfy the following formula (I): 50 < Tm < -3.74 × [Z] + 130 ... (I) If the melting point (Tm, °C) of the copolymer is higher than -3.74 × [Z] + 130 (°C), the random copolymerizability is low and mechanical properties such as impact strength are inferior, and if the melting point is lower than 50 °C, the heat resistance may be inferior, so the properties when applied as a coating film may not be fully exhibited.

[0038] The copolymer (P) of the present invention must contain at least one type of structural unit (A) and at least one type of structural unit (B), for a total of at least two types of monomer units, and may also contain any structural unit (C) other than (A) and (B). The structural units and structural unit amounts of copolymers related to the present invention will now be explained. A structure derived from one molecule each of ethylene and / or α-olefin (A) having 3 to 20 carbon atoms, monomer (B) having a carboxyl group and / or dicarboxylic acid anhydride group, and any monomer (C) other than (A) and (B) is defined as one structural unit in the copolymer. The structural unit amount is the ratio of each structural unit expressed in mol%, when the total structural units in the copolymer are set to 100 mol%.

[0039] - Amount of structural units of ethylene and / or α-olefin (A) having 3 to 20 carbon atoms: The amount of structural units of structural unit (A) related to the present invention is selected from 60.0 to 97.9 mol%, preferably 70.0 to 97.5 mol%, more preferably 80.0 to 97.0 mol%, even more preferably 85.0 to 97.0 mol%, even more preferably 90.0 to 97.0 mol%, and particularly preferably 91.2 to 96.0 mol%. If the amount of structural units derived from ethylene and / or α-olefin (A) having 3 to 20 carbon atoms is less than 60.0 mol%, the toughness of the copolymer will be poor, and if it is more than 97.9 mol%, the crystallinity of the copolymer will be high, which may result in poor transparency.

[0040] - Amount of structural units of monomer (B) having a carboxyl group and / or dicarboxylic acid anhydride group: The amount of structural units of structural unit (B) related to the present invention is selected from 2.0 to 20.0 mol%, preferably 2.9 to 15.0 mol%, more preferably 5.2 to 10.0 mol%, even more preferably 5.2 to 8.0 mol%, particularly preferably 5.2 to 6.0 mol%, and most preferably 5.2 to 5.6 mol%. If the amount of structural units derived from monomer (B) having a carboxyl group and / or dicarboxylic acid anhydride group is less than 2.0 mol%, the adhesion of the copolymer to highly polar dissimilar materials will not be sufficient, and if it is more than 20.0 mol%, sufficient mechanical properties of the copolymer may not be obtained. The monomer having a carboxyl group and / or dicarboxylic acid anhydride group used may be a single monomer or two or more types may be used in combination.

[0041] - Amount of structural units of arbitrary monomer (C): When the ionomer components of the present invention include any monomer (C) other than (A) or (B) above, the amount of structural units of structural units (C) related to the present invention is 0.001 to 20.0 mol%, preferably 0.01 to 15.0 mol%, more preferably 0.1 to 10.0 mol%, even more preferably 1.0 to 5.0 mol%, and particularly preferably selected from 2.0 to 3.6 mol%. If the amount of structural units derived from the arbitrary monomer (C) is 0.001 mol% or more, the copolymer tends to have sufficient flexibility, and if it is 20.0 mol% or less, sufficient mechanical properties of the copolymer tend to be obtained. The arbitrary monomer used may be used alone or in combination of two or more types.

[0042] The proportion of each structural unit in copolymer (P) can be calculated by determining the weight ratio of each structural unit or specific functional group portion based on the type of monomer and the amount (mol) of each structural unit, and then expressing this in weight percent. In the present invention, copolymer (P) is preferable when the amount of structural unit (B) is 7 to 40% by weight, as this makes it easier to control the degree and amount of neutralization and results in a coating film with good adhesion and mechanical properties. The amount of structural unit (B) in copolymer (P) is more preferably 7.5 to 30% by weight.

[0043] - Method for measuring the structural unit amounts of monomers having carboxyl groups and / or dicarboxylic acid anhydride groups in copolymers, and any monomers: The structural unit amounts of monomers having carboxyl groups and / or dicarboxylic acid anhydride groups in copolymers related to the present invention, and any monomers １ It is determined using H-NMR spectroscopy. １ ¹H-NMR is measured by the following method: 200-250 mg of the sample is mixed with o-dichlorobenzene / deuterated bromide (¹¹H). ６ D ５ 2.4 ml of Br = 4 / 1 (volume ratio) and hexamethyldisiloxane, the reference substance for chemical shift, are placed in a 10 mmφ NMR sample tube, purged with nitrogen, sealed, heated and dissolved to form a homogeneous solution for NMR measurement. The NMR measurement is performed at 120°C using a Bruker Japan Co., Ltd. AV400M NMR spectrometer equipped with a 10 mmφ cryoprobe. １ ¹H-NMR measurements are performed with a pulse angle of 4.5°, a pulse interval of 1.8 seconds, and a total of 256 or more cumulative pulses. The chemical shift is set with the methyl proton peak of hexamethyldisiloxane at 0.088 ppm, and the chemical shifts of peaks due to other protons are based on this.

[0044] - Weight-average molecular weight (Mw) and molecular weight distribution (Mw / Mn): The weight-average molecular weight (Mw) of the copolymer related to the present invention is usually 1,000 to 2,000,000, preferably 6,000 to 1,500,000, more preferably 10,000 to 1,000,000, particularly preferably 10,000 to 800,000, and most preferably 10,000 to 100,000. If Mw is less than 1,000, the physical properties of the copolymer, such as mechanical strength and impact resistance, are insufficient, and if Mw exceeds 2,000,000, the melt viscosity of the copolymer becomes very high, which may make molding and processing of the copolymer difficult.

[0045] The ratio of the weight-average molecular weight (Mw) to the number-average molecular weight (Mn) (Mw / Mn) of the copolymer related to the present invention is usually in the range of 1.5 to 4.0, preferably 1.6 to 3.5, and more preferably 1.9 to 2.3. If Mw / Mn is less than 1.5, the copolymer will not have sufficient processability, including molding, and if it exceeds 4.0, the copolymer may have poor mechanical properties. In this specification, (Mw / Mn) may also be expressed as the molecular weight distribution parameter.

[0046] The weight-average molecular weight (Mw) and number-average molecular weight (Mn) of the copolymer related to the present invention are determined by gel permeation chromatography (GPC). Furthermore, the molecular weight distribution parameter (Mw / Mn) is calculated by determining the number-average molecular weight (Mn) using gel permeation chromatography (GPC), and then calculating the ratio of Mw to Mn, Mw / Mn.

[0047] An example of the GPC measurement method related to the present invention is as follows: (Measurement conditions) Equipment used: Waters 150C Detector: FOXBORO MIRAN1A IR detector (measurement wavelength: 3.42 μm) Measurement temperature: 140°C Solvent: Orthodichlorobenzene (ODCB) Column: Showa Denko AD806M / S (3 columns) Flow rate: 1.0 mL / min Injection volume: 0.2 mL (Sample preparation) A 1 mg / mL solution is prepared using ODCB (containing 0.5 mg / mL of BHT (2,6-di-t-butyl-4-methylphenol)) and dissolved at 140°C for approximately 1 hour. (Calculation of molecular weight (M)) This is done by the standard polystyrene method, and the conversion from retention capacity to molecular weight is performed using a calibration curve prepared in advance using standard polystyrene. The standard polystyrene used is, for example, the following brands from Tosoh Corporation (F380, F288, F128, F80, F40, F20, F10, F4, F1, A5000, A2500, A1000), or monodisperse polystyrene from Showa Denko (S-7300, S-3900, S-1950, S-1460, S-1010, S-565, S-152, S-66.0, S-28.5, S-5.05, each in a 0.07 mg / ml solution). A calibration curve is created by injecting 0.2 mL of a solution in ODCB (containing 0.5 mg / mL BHT) so that each of these compounds is at 0.5 mg / mL. The calibration curve is approximated by a cubic equation obtained by the least squares method, or by approximating the logarithm of the elution time with a quartic equation. The viscosity formula [η] = K × Mα used for conversion to molecular weight (M) uses the following values: Polystyrene (PS): K = 1.38 × 10 －４ α = 0.7 Polyethylene (PE): K = 3.92 × 10 －４ α = 0.733 Polypropylene (PP): K = 1.03 × 10 －４ α = 0.78

[0048] • Melting point (Tm, °C): The melting point of the copolymer is indicated by the maximum peak temperature of the endothermic curve measured by differential scanning calorimeter (DSC). The maximum peak temperature refers to the temperature of the peak with the greatest height from the baseline when multiple peaks are shown in the endothermic curve obtained when heat flow (mW) is plotted on the vertical axis and temperature (°C) on the horizontal axis in a DSC measurement. If there is only one peak, it refers to the temperature of that peak. The melting point of the copolymer (P) of the present invention is preferably 50°C to 140°C, more preferably 60°C to 138°C, and most preferably 70°C to 135°C. If it is lower than this range, the heat resistance will not be sufficient, and if it is higher than this range, the adhesive properties may be poor. The melting point can be determined, for example, by using DSC (DSC7020) manufactured by SII Nanotechnology Co., Ltd., packing approximately 5.0 mg of the sample into an aluminum pan, raising the temperature to 200°C at 10°C / min, holding it isothermally at 200°C for 5 minutes, then lowering the temperature to 20°C at 10°C / min, holding it isothermally at 20°C for 5 minutes, and then raising the temperature again to 200°C at 10°C / min. The absorption curve obtained during this process can be determined from the absorption curve.

[0049] Melt Flow Rate (MFR) The copolymer (P) of the present invention has a melt flow rate (MFR) of 10 to 5000 g / 10 min at a temperature of 190°C and a load of 2.16 kg, preferably 10.5 to 3000 g / 10 min, and more preferably 11 to 2500 g / 10 min. An MFR of greater than 10 g / 10 min of the copolymer is preferable from the viewpoint of ease of preparation and handling, as it improves dispersibility in aqueous media.

[0050] The copolymer (P) of the present invention is preferably manufactured in the presence of a transition metal catalyst, from the viewpoint of having a linear molecular structure. It is known that the molecular structure of the copolymer differs depending on the manufacturing method, such as polymerization by a high-pressure radical polymerization process or polymerization using a metal catalyst. This difference in molecular structure can be controlled by selecting the manufacturing method, but the molecular structure can also be estimated by the complex modulus measured with a rotational rheometer, for example, as described in Japanese Patent Application Publication No. 2010-150532.

[0051] • Production of copolymer (P) From the viewpoint of having a linear molecular structure, it is preferable that the copolymer (P) is produced in the presence of a transition metal catalyst. The type of polymerization catalyst used in the production of copolymer (P) is not particularly limited as long as it is capable of copolymerizing structural unit (A), structural unit (B), and any structural unit (C), but examples include transition metal compounds of groups 5 to 11 having a chelating ligand. Specific examples of preferred transition metals include vanadium atoms, niobium atoms, tantalum atoms, chromium atoms, molybdenum atoms, tungsten atoms, manganese atoms, iron atoms, platinum atoms, ruthenium atoms, cobalt atoms, rhodium atoms, nickel atoms, palladium atoms, copper atoms, etc. Among these, transition metals of groups 8 to 11 are preferred, more preferably transition metals of group 10, and particularly preferably nickel (Ni) and palladium (Pd). These metals may be used individually or in combination of multiple metals. Chelating ligands contain ligands that have at least two atoms selected from the group consisting of P, N, O, and S, and are bidentate or multidentate coordinated, and are electronically neutral or anionic. Examples of chelating ligand structures are provided in a review by Brookhart et al. (Chem. Rev., 2000, 100, 1169). Preferably, chelating ligands include bidentate anionic P,O ligands. Examples of bidentate anionic P,O ligands include phosphosulfonic acid, phosphocarboxylic acid, phosphorus phenol, and phosphorus enolate. Other chelating ligands include bidentate anionic N,O ligands. Examples of bidentate anionic N,O ligands include salicylaldehyde and pyridinecarboxylic acid. Other examples of chelating ligands include diimine ligands, diphenoxide ligands, and diamide ligands.

[0052] Typical catalysts for transition metal compounds of groups 5 to 11 having chelating ligands include so-called SHOP catalysts and Drent catalysts. SHOP catalysts are catalysts in which a phosphorus ligand having an optionally substituted aryl group is coordinated to nickel metal (see, for example, WO2010-050256). Drent catalysts are catalysts in which a phosphorus ligand having an optionally substituted aryl group is coordinated to palladium metal (see, for example, Japanese Patent Application Publication No. 2010-202647). Alternatively, the catalyst described in Patent Document 2 above can be used.

[0053] • Polymerization method for copolymers: The polymerization method for copolymers according to the present invention preferably uses the above-mentioned transition metal catalyst, but other conditions are not particularly limited as long as a substantially linear polymer can be obtained. Examples of polymerization methods include slurry polymerization in which at least a portion of the resulting polymer becomes a slurry in the medium, bulk polymerization using the liquefied monomer itself as the medium, gas-phase polymerization carried out in vaporized monomer, or high-pressure ionic polymerization in which at least a portion of the resulting polymer dissolves in monomer liquefied at high temperature and pressure. The polymerization form may be batch polymerization, semi-batch polymerization, or continuous polymerization. Living polymerization may also be carried out, or polymerization may be carried out while chain transfer occurs concurrently. Furthermore, a so-called chain shuttling agent (CSA) may be used in combination during polymerization to carry out a chain shuttling reaction or coordinated chain transfer polymerization (CCTP). Specific manufacturing processes and conditions are disclosed, for example, in Japanese Patent Publication No. 2010-260913 and Japanese Patent Publication No. 2010-202647.

[0054] - Method for introducing carboxyl groups and / or dicarboxylic acid anhydride groups into copolymers: The method for introducing carboxyl groups and / or dicarboxylic acid anhydride groups into copolymers according to the present invention is not particularly limited. Carboxyl groups and / or dicarboxylic acid anhydride groups can be introduced by various methods without departing from the spirit of the present invention. Examples of methods for introducing carboxyl groups and / or dicarboxylic acid anhydride groups include directly copolymerizing a comonomer having carboxyl groups and / or dicarboxylic acid anhydride groups, or copolymerizing another monomer having a functional group that generates carboxyl groups, and then introducing carboxyl groups and / or dicarboxylic acid anhydride groups by modification.

[0055] Methods for introducing carboxyl groups and / or dicarboxylic acid anhydride groups through modification include, for example, when introducing a carboxylic acid, copolymerizing an acrylic acid ester as a precursor and then hydrolyzing it to convert it into a carboxylic acid, or copolymerizing t-butyl acrylate as a precursor and then converting it into a carboxylic acid by thermal decomposition.

[0056] When hydrolyzing or thermally decomposing as described above, conventionally known acid or base catalysts may be used as additives to promote the reaction. There are no particular restrictions on the acid or base catalyst, but for example, alkali metal or alkaline earth metal hydroxides such as sodium hydroxide, potassium hydroxide, and lithium hydroxide; alkali metal or alkaline earth metal carbonates such as sodium bicarbonate and sodium carbonate; solid acids such as montmorillonite; inorganic acids such as hydrochloric acid, nitric acid, and sulfuric acid; and organic acids such as formic acid, acetic acid, benzoic acid, citric acid, p-toluenesulfonic acid, trifluoroacetic acid, and trifluoromethanesulfonic acid can be used as appropriate. From the viewpoint of reaction promoting effect, cost, and equipment corrosion, sodium hydroxide, potassium hydroxide, sodium carbonate, p-toluenesulfonic acid, and trifluoroacetic acid are preferred, and p-toluenesulfonic acid and trifluoroacetic acid are more preferred.

[0057] The carboxyl groups and / or dicarboxylic acid anhydride groups contained in the copolymer (P) may be incorporated into the polymer chain by graft modification. Graft modification is achieved by adding predetermined amounts of the base resin and a polar group-containing compound that serves as a source of carboxyl groups and / or dicarboxylic acid anhydride groups, along with a radical initiator, and then melt-kneading or modifying in a solvent using one or more polymerization reactors or single-screw and / or twin-screw extruders. Specifically, examples include melt-kneading methods using extruders, Banbury mixers, kneaders, etc., solution methods in which the material is dissolved in a suitable solvent, slurry methods in which the material is suspended in a suitable solvent, or so-called gas-phase grafting methods, and these methods are known to those skilled in the art.

[0058] (5) Ionomers The ionomers related to the present invention are ionomers having a substantially linear structure, wherein at least a portion of the carboxyl groups and / or dicarboxylic acid anhydride groups of the structural unit (B) in the copolymer (P) are converted to a metal-containing carboxylate salt containing at least one metal ion selected from Group 1, 2, or 12 of the periodic table. The ionomers are obtained by reacting an ionomer-based resin with a metal salt, as described below, and reactions that cleave the molecular chains of the polymer do not usually occur. For this reason, structural parameters such as the molar ratio of comonomers, the degree of branching, and randomness are usually preserved between the ionomer-based resin and the ionomer.

[0059] - Ionomer structure: The ionomers related to the present invention have a substantially linear structure, similar to the copolymers related to the present invention. Therefore, the absolute value of the complex modulus G measured with a rotational rheometer. ＊ = The phase angle δ at 0.1 MPa is characterized by being 50 to 75 degrees. The lower limit of the phase angle δ may be 51 degrees or more, and the upper limit of the phase angle δ may be 64 degrees or less. ＊If the phase angle (G) is lower than 50 degrees (Mw / Mn ≤ 0.1 MPa), the molecular structure of the ionomer will exhibit a structure with excessive long-chain branching, resulting in inferior mechanical strength. As mentioned above, if Mw / Mn ≤ 4, the value of the phase angle δ is an indicator of the amount of long-chain branching. If the Mw / Mn of the ionomer is 1.5 or higher, even if the molecular structure does not contain long-chain branching, δ(G) ＊ (=0.1 MPa) The value will never exceed 75 degrees.

[0060] The metal ions contained in the ionomer related to the present invention are not particularly limited and may include metal ions used in conventionally known ionomers. Among the metal ions, it is preferable that they be metal ions of Group 1, Group 2, or Group 12 of the periodic table, and Li ＋ Na ＋ _K ＋ , Rb ＋ , Cs ＋ Mg ２＋ Ca ２＋ , Sr ２＋ Ba ２＋ and Zn ２＋ More preferably, at least one selected from the group consisting of is preferred. Even more preferably, Li ＋ Na ＋ _K ＋ Mg ２＋ Ca ２＋ , and Zn ２＋ It is particularly preferably a Group 1 element, specifically Na ＋ These metal ions can also be mixed together in two or more types as needed.

[0061] ・Degree of neutralization (mol%) The metal ion content is preferably such that it contains an amount that neutralizes at least some or all of the carboxyl groups and / or dicarboxylic acid anhydride groups in the copolymer as an ionomer base resin. The preferred degree of neutralization (average degree of neutralization) is 5 to 95 mol%, more preferably 10 to 90 mol%, and even more preferably 20 to 80 mol%. The degree of neutralization can be determined from the ratio of the total amount of mol of the valence × mol of the metal ion to the total amount of carboxyl groups that may be contained in the carboxyl groups and / or dicarboxylic acid anhydride groups in the copolymer. Since the dicarboxylic acid anhydride group opens its ring to become a dicarboxylic acid when forming a carboxylate salt, the total amount of mol of the carboxyl groups is determined by assuming that there are 2 mol of carboxyl groups per mol of dicarboxylic acid anhydride group. Also, for example, Zn ２＋ For divalent metal ions such as those mentioned above, assuming that they can form a salt with 2 mol of carboxyl groups per mol, the total amount of molecules corresponding to the degree of neutralization is calculated using 2 × mol. A high degree of neutralization results in high tensile strength and tensile fracture stress of the ionomer, and a low tensile fracture strain, but tends to result in a low melt flow rate (MFR) of the ionomer. On the other hand, a low degree of neutralization yields an ionomer with a moderate MFR, but tends to result in low tensile modulus and tensile fracture stress, and a high tensile fracture strain.

[0062] • Neutralization amount (mol%) The neutralization amount is the amount of carboxylic acid groups neutralized by metal ions, i.e., the content of metal-containing carboxylic acid bases in the ionomer, and can be determined from the ratio of the total amount of mol of the valence × mol of metal ions to the total amount of carboxyl groups that can be contained in the carboxyl groups and / or dicarboxylic acid anhydride groups in the copolymer (P). The ionomer of the present invention preferably has a neutralization amount of 2.0 to 15 mol%. Although ionomers contain metal ions in the polymer, metal ions play a role in increasing the affinity of the polymer for water, so if the amount of metal ions is above the lower limit, the dispersibility of the ionomer, which is a polymer, in aqueous media will be further improved. In addition, when the ionomer is in a low temperature state that does not melt, such as when it is in the form of a coating film, the molecular momentum decreases and at the same time the metal ions form pseudo-crosslinks, which contribute to an increase in viscosity, and this pseudo-crosslink structure makes the molecular structure network-like, which also contributes to an improvement in impact strength. The amount of ionomer neutralized is more preferably 2.3 to 14.0 mol%, and even more preferably 2.5 to 13.5 mol%. The amount of ionomer neutralized can be calculated from the above degree of neutralization and the amount of structural units (B) in the ionomer base resin, and is determined by [amount of structural units (B) (mol%) × degree of neutralization (%) / 100].

[0063] ・Method for producing ionomers The ionomers according to the present invention may be obtained by a conversion step in which a copolymer of ethylene and / or α-olefin / unsaturated carboxylic acid having 3 to 20 carbon atoms, obtained by the method for introducing carboxyl groups and / or dicarboxylic acid anhydride groups into the copolymer as described above, is treated with a metal salt containing at least one metal ion selected from Group 1, 2, or 12 of the periodic table to convert it into a metal-containing carboxylate salt. Alternatively, the ionomers according to the present invention may be obtained by a heating conversion step in which an ethylene and / or α-olefin / unsaturated carboxylic acid ester copolymer having 3 to 20 carbon atoms is heated and at least some of the ester groups in the copolymer are converted into a metal-containing carboxylate salt containing at least one metal ion selected from Group 1, 2, or 12 of the periodic table.

[0064] When an ionomer is produced by introducing carboxyl groups and / or dicarboxylic acid anhydride groups into a polymer, the production method is as follows, for example: A metal ion source is prepared by heating and kneading a metal salt with a metal ion-capturing substance such as an ethylene / methacrylic acid (MAA) copolymer, and then the ionomer is obtained by adding the metal ion source to the ionomer base resin in an amount that results in a desired degree of neutralization and kneading.

[0065] Furthermore, in the heating conversion step, (i) the ethylene and / or C3-C20 α-olefin / unsaturated carboxylic acid ester copolymer may be heated to obtain an ethylene and / or C3-C20 α-olefin / unsaturated carboxylic acid copolymer by hydrolysis or thermal decomposition, and then reacted with a compound containing a metal ion of group 1, 2, or 12 of the periodic table to convert the carboxylic acid in the ethylene and / or C3-C20 α-olefin / unsaturated carboxylic acid copolymer into the metal-containing carboxylate salt; or (ii) the ethylene and / or C3-C20 α-olefin / unsaturated carboxylic acid ester copolymer may be heated to hydrolyze or thermal decompose the ester groups of the copolymer, and reacted with a compound containing a metal ion of group 1, 2, or 12 of the periodic table to convert the ester group portion in the ethylene and / or C3-C20 α-olefin / unsaturated carboxylic acid ester copolymer into the metal-containing carboxylate salt.

[0066] The metal ion-containing compound may be an oxide, hydroxide, carbonate, bicarbonate, acetate, or formate of a metal from Group 1, 2, or 12 of the periodic table. Particularly preferred are hydroxides or salts of Group 1 metals. The metal ion-containing compound may be supplied to the reaction system in granular or fine powder form, dissolved or dispersed in water or an organic solvent before being supplied to the reaction system, or a masterbatch may be prepared using an ethylene / unsaturated carboxylic acid copolymer or an olefin copolymer as the base resin and supplied to the reaction system. To ensure the reaction proceeds smoothly, it is preferable to prepare a masterbatch and supply it to the reaction system.

[0067] The reaction with metal ions can be carried out with the base resin dispersed in an aqueous medium. By reacting the metal salt in an aqueous medium, the by-product water can be used directly as the dispersion medium, allowing for the production of an aqueous dispersion in a single pot. The ionomer can also be isolated, in which case the reaction with the metal ion-containing compound may be carried out by melt-kneading using various types of equipment such as a vented extruder, Banbury mixer, or roll mill, and the reaction may be carried out in batch or continuous order. To remove the by-products of the reaction, such as water and carbon dioxide, the reaction can be carried out continuously using an extruder equipped with a degassing device, such as a vented extruder. When reacting with the metal ion-containing compound, a small amount of water may be injected to accelerate the reaction.

[0068] The heating temperature for ethylene and / or α-olefin / unsaturated carboxylic acid ester copolymers having 3 to 20 carbon atoms should be such that the ester is converted to a carboxylic acid. If the heating temperature is too low, the ester will not be converted to a carboxylic acid, and if it is too high, decarbonylation or decomposition of the copolymer may occur. When melt-kneading, the heating temperature is preferably in the range of 80°C to 350°C, more preferably 100°C to 340°C, even more preferably 150°C to 330°C, and even more preferably 200°C to 320°C.

[0069] The reaction time varies depending on the heating temperature and the reactivity of the ester group, but is usually 1 minute to 50 hours, more preferably 2 minutes to 30 hours, even more preferably 2 minutes to 10 hours, even more preferably 2 minutes to 3 hours, and particularly preferably 3 minutes to 2 hours.

[0070] In the above process, there are no particular restrictions on the reaction atmosphere, but it is generally preferable to carry it out under an inert gas stream. Examples of inert gases that can be used include nitrogen, argon, and carbon dioxide atmospheres. Small amounts of oxygen or air may be present.

[0071] There are no particular restrictions on the reactor used in the above process, as long as it can stir the copolymer substantially uniformly, it is not limited in any way. A glass container or autoclave (AC) equipped with a stirrer may be used, or any conventionally known kneader such as a Brabender plastograph, a single-screw or twin-screw extruder, a heavy-duty screw kneader, a Banbury mixer, a kneader, or a roll can be used.

[0072] Whether a metal ion has been introduced into an ionomer-based resin and it has become an ionomer can be confirmed by measuring the IR spectrum of the obtained resin and examining the decrease in the peak originating from the carbonyl group of the carboxylic acid (dimer). Similarly, the degree of neutralization can be confirmed not only by calculation from the molar ratio mentioned above, but also by examining the decrease in the peak originating from the carbonyl group of the carboxylic acid (dimer) and the increase in the peak originating from the carbonyl group of the carboxylic acid base.

[0073] <Ionomer Properties> ・Melting point of ionomer (Tm, °C) The melting point (Tm, °C) of the ionomer related to the present invention is preferably 50°C to 140°C, more preferably 60°C to 138°C, and most preferably 70°C to 135°C. If it is lower than this range, the heat resistance will not be sufficient, and if it is higher than this range, the adhesive properties may be poor. Among the ionomers related to the present invention, ionomers based on a binary copolymer consisting only of structural unit (A) and structural unit (B) have a melting point of 90°C or higher, preferably 95°C or higher, and more preferably 100°C or higher, while ionomers based on a ternary or more multicomponent copolymer have a melting point of less than 100°C, preferably less than 95°C, and more preferably less than 90°C.

[0074] • MFR: In the ionomer of the present invention, the melt flow rate (MFR) at a temperature of 190°C and a load of 2.16 kg is 10 to 5000 g / 10 min, preferably 10.5 to 3000 g / 10 min, and more preferably 11 to 2500 g / 10 min. When the MFR of the ionomer is within this range, it has high dispersibility in aqueous media and is easier to prepare.

[0075] (6) Resin composition As a resin for aqueous dispersions, the ionomer of the present invention may be used alone or as part of a resin composition blended with other resin components. Hereinafter, when the present invention refers to a "resin composition containing an ionomer," it includes the ionomer resin alone or a composition blended with other resin components or additives. Other resin components that can be blended in the ionomer resin composition of the present invention are not particularly limited as long as they are compatible with the ionomer and can be used as an aqueous dispersion. Examples include polyethylene, ethylene-vinyl acetate copolymer, ethylene-acrylic acid ester copolymer, polyester, other ionomers, etc. Furthermore, two or more materials can be used in combination. The amount of these resin components blended is not particularly limited as long as it does not impair the effects of the present invention. The resin composition for aqueous dispersions of the present invention is characterized by containing the above-mentioned ionomer, and the amount thereof can be arbitrarily selected. However, it is preferable that the resin composition for aqueous dispersions contains 10 to 100% by weight of the above-mentioned ionomer, more preferably 30 to 90% by weight, even more preferably 50 to 70% by weight, and particularly preferably 60 to 70% by weight. The higher the content of the specific ionomer according to the present invention in the resin composition, the more the excellent physical properties resulting from the use of the ionomer can be fully exhibited. However, the amount of the ionomer can be arbitrarily selected from the viewpoint of required physical properties and cost.

[0076] The resin composition containing the ionomer used in the present invention may be stored in a pelletized state after mixing various additives and polymer components that are added or blended as needed using a Henschel mixer, super mixer, tumbler mixer, etc., and then heating and kneading with a single-screw or twin-screw extruder, kneader, etc. However, it is preferable to disperse it in an aqueous medium and handle it using the method described later.

[0077] 2. Aqueous Dispersion One aspect of the present invention is an aqueous dispersion containing the above-mentioned ionomer and water. In the aqueous dispersion, the ionomer particles are uniformly dispersed in a water-containing medium as particles with an average particle diameter of 1 to 1000 nm, preferably 5 to 500 nm. The ionomer used in the aqueous dispersion in the present invention has a polymer chain that is substantially linear and has a structure that is completely different from ionomers conventionally used in aqueous dispersions. Generally, linear molecules have a higher melting point and are less likely to melt than branched molecules, and molecules with many branched structures have many gaps in the branched structure and a structure that can easily incorporate solvents such as water molecules, thus having a high affinity for solvents. For this reason, conventional polymers with many branches in the polymer chain are considered advantageous for preparing dispersions. However, according to the present invention, a uniform aqueous dispersion can be obtained despite a structure that was conventionally considered unsuitable as a dispersion phase in an aqueous system. Furthermore, while it had been suggested that the ionomer of the present invention could achieve high abrasion resistance and transparency through molding of molten resin, the formation of coating films and the required physical properties of the coating films from dispersions remained unknown. The present invention is based on the discovery that linear ionomers can be surprisingly uniformly dispersed in aqueous media, that the dispersion state can be stably maintained over a long period of time, and that coating films with various excellent physical properties can be formed.

[0078] The dispersion medium for preparing an aqueous dispersion is an aqueous-based medium containing water. As the aqueous-based medium, water such as tap water, deionized water, distilled water, or ultrapure water, or a mixture of water and a hydrophilic organic solvent can be used. Since the process of creating a coating film from the aqueous dispersion includes a step of volatilizing the dispersion medium by heating, for environmental reasons, it is preferable that the dispersion medium consists only of water and does not contain a hydrophilic organic solvent. However, a hydrophilic organic solvent may be used for purposes such as improving the dispersibility of the ionomer resin.

[0079] The dispersion medium for preparing the aqueous dispersion may contain a hydrophilic organic solvent other than water. The hydrophilic organic solvent is preferably one or more selected from the group consisting of alcohols, glycols, glycol monoethers, ketones, and amides, and may also be a mixture of two or more miscible hydrophilic organic solvents. From the viewpoint of film formation, the hydrophilic organic solvent is preferably one with a boiling point of 150°C or lower. Specific examples of hydrophilic organic solvents include methanol, ethanol, n-propanol, isopropanol, butanol, ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol mono-n-butyl ether, ethylene glycol mono-t-butyl ether, acetone, methyl ethyl ketone, γ-butyrolactone (GBL), dioxane, 4-hydroxy-4-methyl-2-pentanone, dimethylformamide, N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, N-ethylpyrrolidone, and N-methyl-2-pyrrolidone. The amount of hydrophilic organic solvent in the aqueous medium is preferably 0 to 20% by weight, and more preferably 0 to 15% by weight. As described above, it is particularly preferable that the amount of hydrophilic organic solvent be 0% by weight.

[0080] The amount of ionomer in the aqueous dispersion is not particularly limited as long as the concentration of ionomer is sufficiently high so as not to reduce the efficiency of coating film formation, but it is preferable to use an amount that allows for uniform dispersion of the ionomer resin. The amount of ionomer is preferably 1 to 60% by weight, and more preferably 10 to 50% by mass, relative to the total amount of the aqueous dispersion.

[0081] The aqueous dispersion may further contain, without departing from the spirit of the present invention, conventionally known surfactants, processing aids, dispersion aids, flow-enhancing additives, lubricants, pigments, dyes, flame retardants, impact-improving agents, nucleating agents, antiblocking agents, pH adjusters, thermal stabilizers, antioxidants, ultraviolet absorbers, antistatic agents, defoamers, chelating agents, coupling agents, and the like as additives.

[0082] The aqueous dispersion is preferably prepared within the above-mentioned range of blending amounts, but it is more preferable if the aqueous dispersion is prepared so that its viscosity is in the range of 5 to 10,000 mPa·s, preferably 10 to 5,000 mPa·s, as this results in a uniform dispersion with excellent handling properties. Here, the viscosity of the aqueous dispersion is the value measured using a rheometer (MCR CC27) under conditions of 25°C and a rotation speed of 60 rpm.

[0083] Since the aqueous dispersion contains a metal salt of a carboxylic acid as an ionomer, its pH is preferably in the range of 7 to 11. pH adjustment can be performed with a pH adjusting agent as an additive, and those known to those skilled in the art can be used.

[0084] The method for producing the aqueous dispersion of the present invention can be broadly classified into two types. One method involves adding an ionomer-based resin to an aqueous medium containing a salt of a metal ion to be introduced into the ionomer, and then heating and stirring the mixture to simultaneously neutralize the ionomer-based resin and prepare the dispersion. When the salt of the metal ion used is a water-soluble hydroxide, the water produced as a by-product of the neutralization reaction can be used directly in the aqueous medium. The other method involves directly adding a pre-prepared ionomer to an aqueous medium and then heating and stirring the mixture. Pre-preparing the ionomer significantly increases the viscosity of the resin, which may affect its solubility depending on the formulation; therefore, it is preferable to prepare the dispersion by performing a neutralization reaction in water.

[0085] The heating temperature in the production of the aqueous dispersion is usually 250°C or lower, preferably 200°C or lower, and more preferably 160°C or lower. The lower limit of the heating temperature is preferably above the melting point of the ionomer, but for example, it is 50°C or higher, preferably 90°C or higher, and preferably 100°C or higher. The heating temperature may be varied in stages.

[0086] The preparation of aqueous dispersions involves stirring. Known equipment can be used for stirring, but it is preferable to use equipment equipped with stirring blades angled to the horizontal. The stirring speed is also affected by the scale of the dispersion preparation, but is usually performed in a range where the rotation speed of the stirring blades is between 300 and 1500 rpm. The stirring speed may be varied in stages.

[0087] Other conditions in the production of aqueous dispersions can be set according to those known to the art. For example, stirring can be carried out under an inert gas atmosphere such as nitrogen or a noble gas, or under pressurized conditions using an autoclave. The stirring time is not particularly limited as long as it is confirmed that a homogeneous dispersion has been obtained, and can be set appropriately considering conditions such as stirring speed and heating temperature. After stirring is complete, treatment such as filtration may be performed to remove aggregated insoluble components.

[0088] 3. Coating Film One embodiment of the present invention relates to a coating film molded using an aqueous dispersion resin containing the ionomer, and an article containing the coating film. The thickness of the coating film can be arbitrarily selected depending on its application, but is usually about 1 to 20 μm, preferably 2 to 15 μm, and more preferably 3 to 10 μm. The surface of the coating film can be made to match the shape of the substrate to which it is applied, and can take any shape such as a quadrilateral, circle, or triangle, and may have irregularities.

[0089] A coating film can be obtained on a substrate by applying the aqueous dispersion of the present invention to the substrate and drying it. The method of applying the aqueous dispersion is well known and is not particularly limited as long as it allows for application to a uniform thickness. For example, methods such as roll coating, brush coating, and spray coating can be used. At this time, the substrate to which the aqueous dispersion is applied may be pre-coated with a primer or subjected to surface treatment such as corona treatment. The coating film is generally formed by heat treatment. Heating is performed at a temperature below the boiling point of the aqueous medium. Furthermore, after heating, crosslinking treatment by electron beam irradiation can be performed to further improve the physical properties of the coating film.

[0090] The substrate to which the aqueous dispersion of the present invention is applied is not particularly limited and can be used with metals, natural materials, synthetic resins, and the like. The shape of the substrate is also not particularly limited. Examples of applicable substrates include metals such as iron, copper, aluminum, and stainless steel; wood, paper, rayon, leather, rubber materials such as natural rubber and synthetic rubber; thermosetting resins such as phenolic resins and polyurethanes; olefin polymers; styrene polymers; and thermoplastic resins such as polyesters, polyamides, polycarbonates, and polyvinyl chloride.

[0091] The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to these examples. The physical properties in the examples and comparative examples were measured and evaluated by the methods shown below. In the table, "no data" means not measured, and "not detected" means below the detection limit.

[0092] <Synthesis of Metal Complexes> (1) Synthesis of B-423 / Ni Complex The B-423 / Ni complex was synthesized using 2-bis(2,6-dimethoxyphenyl)phosphano-6-(2,6-diisopropylphenyl)phenol (B-423 ligand) in accordance with Example 1 of International Publication No. 2010 / 050256, by reacting B-423 and Ni(acac)2 in a 1:1 ratio with bisacetylacetonatonickel(II) (referred to as Ni(acac)2).

[0093] (2) Synthesis of the B-27DM / Ni complex The B-27DM / Ni complex was synthesized using the following 2-bis(2,6-dimethoxyphenyl)phosphano-6-pentafluorophenylphenol ligand (B-27DM) according to Synthesis Example 4 described in International Publication No. 2010 / 050256. Following Example 1 of International Publication No. 2010 / 050256, a nickel complex (B-27DM / Ni) was synthesized by reacting B-27DM and Ni(COD)2 in a 1:1 ratio using bis(1,5-cyclooctadiene)nickel(0) (referred to as Ni(COD)2).

[0094] <Production Examples 1-6: Ionomer-Based Resins> For the preparation of aqueous dispersions, ethylene-t-butyl acrylate copolymer was used as the ionomer-based resin, which was produced as a pelletized material by carrying out a polymerization reaction under the conditions shown in Table 1 below, using B-423 / Ni or B-27DM / Ni as the metal complex catalyst. The physical properties of the copolymers obtained in each production example are shown together in Table 1. The methods for measuring each physical property are shown below.

[0095] <Comonomer Amount, Methyl Branching, Ethyl Branching, Butyl Branching> Method for measuring the amount of structural units and branching number derived from monomers having carboxyl groups and / or dicarboxylic anhydride groups, and acyclic monomers in copolymers: The amount of structural units and branching number per 1,000 carbon atoms derived from monomers having carboxyl groups and / or dicarboxylic anhydride groups, and acyclic monomers in the copolymer of the present invention １３ It is determined using C-NMR spectroscopy. １３ ¹¹C-NMR is measured by the following method: 200-300 mg of the sample is mixed with o-dichlorobenzene (¹¹C). ６ H ４ Cl ２ ) and deuterated bromide benzene (C ６ D ５ Mixed solvent of Br (C ６ H ４ Cl ２ / C ６ D ５ 2.4 ml of Br (2 / 1 by volume) and hexamethyldisiloxane, the reference substance for chemical shift, are placed in a 10 mm diameter NMR sample tube, purged with nitrogen, sealed, and heated to dissolve into a homogeneous solution, which is then used as the NMR measurement sample. NMR measurement is performed at 120°C using a Bruker Japan AV400M NMR spectrometer equipped with a 10 mm diameter cryoprobe. １３ ¹³C-NMR is measured using the reverse gate decoupling method with a sample temperature of 120°C, a pulse angle of 90°, a pulse interval of 51.5 seconds, and a total of 512 or more integration cycles. The chemical shift is that of hexamethyldisiloxane. １３ Set the C signal to 1.98 ppm, and the other １３ The chemical shift of the signal due to C is based on this. １３In 13C NMR, by identifying signals specific to monomers or branches in a copolymer and comparing their intensities, the amount of structural units and the number of branches of each monomer in the copolymer can be analyzed. The location of signals specific to monomers or branches can be determined by referring to known data or by independently identifying them depending on the sample. Such analytical methods are generally possible for those skilled in the art.

[0096] <Melting Point and Crystallinity> The melting point is indicated by the peak temperature of the endothermic curve measured by a differential scanning calorimeter (DSC). A DSC (DSC7020) manufactured by SII Nanotechnology Co., Ltd. was used for the measurement, and the following measurement conditions were followed. Approximately 5.0 mg of the sample was placed in an aluminum pan and heated to 200°C at 10°C / min, held at 200°C for 5 minutes, and then cooled to 30°C at 10°C / min. After holding at 30°C for 5 minutes, the maximum peak temperature of the absorption curve when the temperature was raised again at 10°C / min was taken as the melting point Tm, and the heat of fusion (ΔH) was determined from the endothermic peak area of ​​fusion. The degree of crystallinity (%) was determined by dividing the heat of fusion by the heat of fusion of perfect high-density polyethylene (HDPE), which is 293 J / g.

[0097] <Phase Angle> The sample is placed in a 1.0 mm thick heat press mold and preheated in a hot press machine at a surface temperature of 180°C for 5 minutes. After that, residual gas in the molten resin is removed by repeatedly applying and removing pressure, and then it is pressurized at 4.9 MPa and held for 5 minutes. After that, the sample is transferred to a press machine at a surface temperature of 25°C and cooled by holding it at a pressure of 4.9 MPa for 3 minutes to create a press plate made from the sample with a thickness of approximately 1.0 mm. A press plate made from the sample is processed into a 25 mm diameter circle and used as the sample. The dynamic viscoelasticity is measured using a Rheometrics ARES type rotary rheometer under a nitrogen atmosphere under the following conditions: Plate: φ25 mm parallel plate Temperature: 160°C Strain: 10% Measurement angular frequency range: 1.0 × 10 －２ ~1.0 x 10 ２rad / s Measurement interval: 5 points / decade The phase angle δ is plotted against the common logarithm logG* of the absolute value G*(Pa) of the complex modulus of elasticity, and the value of δ (degrees) at the point corresponding to logG* = 5.0 is taken as δ(G* = 0.1 MPa). If there is no point corresponding to logG* = 5.0 among the measurement points, the value of δ at logG* = 5.0 is obtained by linear interpolation using two points around logG* = 5.0. Also, if all measurement points are logG* < 5, the value of δ at logG* = 5.0 is obtained by extrapolating using a quadratic curve with the values ​​of the three points with the largest logG* values.

[0098] The ionomer-based resins in production examples 1 to 6 were all linear copolymers that satisfied the conditions for methyl branching number and phase angle δ.

[0099]

[0100] <Preparation of Aqueous Dispersion 1> The pelletized copolymers (15 g) obtained in Production Examples 2 to 6 were each added to an autoclave equipped with a stirring blade along with ion-exchanged water (40 mL), the autoclave was purged with nitrogen, and pressurized to 0.6 MPa. Subsequently, the internal temperature was heated to 130°C while stirring at 50 rpm. After confirming that stirring was being performed without excessive load, an amount of sodium hydroxide aqueous solution sufficient to achieve the predetermined degree of neutralization was pumped into the autoclave. At this time, if there was a possibility that the pellets would stick together and the stirring load would increase, stirring was temporarily stopped until the temperature reached 130°C, and after the resin melted, stirring was resumed. If the load on the stirring shaft did not decrease even after the temperature exceeded 130°C, stirring was resumed after adding sodium hydroxide aqueous solution. After confirming that the sodium hydroxide aqueous solution had been added and the reaction mixture was stirring, the mixture was stirred at 700 rpm for 2 hours. Then, while stirring at 700 rpm, the internal temperature was cooled to below 70°C at a rate of less than 1°C / min, and the mixture was returned to atmospheric pressure. The resulting polymer dispersion was pressure filtered through a 60-mesh filter to obtain an aqueous dispersion of the ionomer.

[0101] <Production of aqueous dispersion 2: Direct dispersion of ionomer> In a Toyo Seiki Co., Ltd. Laboplast Mill: Roller Mixer R60 equipped with a 60 ml capacity mini mixer, 22 g of ethylene / methacrylic acid (MAA) copolymer (Mitsui Dow Polychemical Co., Ltd. brand: Nuclel N1050H) and 18 g of sodium carbonate were added and mixed at 180°C and 40 rpm for 3 minutes to prepare a Na ion source. Next, in a Toyo Seiki Co., Ltd. Laboplast Mill: Roller Mixer R60 equipped with a 60 ml capacity mini mixer, 40 g of the ionomer base resin obtained in Production Examples 1 to 6 was added and mixed at 160°C and 40 rpm for 3 minutes to dissolve. After that, the Na ion source was added to the desired degree of neutralization and mixed at 250°C and 40 rpm for 5 minutes to produce the ionomer resin.

[0102] 15 g of pelletized ionomer and 40 mL of deionized water were added to an autoclave equipped with a stirring blade. The autoclave was then purged with nitrogen and pressurized to 0.6 MPa. The internal temperature was then heated to 130°C while stirring at 50 rpm. If the pellets were to stick together and the stirring load increased, stirring was temporarily stopped until the temperature reached 130°C, and then resumed after the resin had melted. After confirming that the reaction mixture was stirring, it was stirred at 700 rpm for 2 hours, and then the internal temperature was cooled to below 70°C at a rate of less than 1°C / min while stirring at 700 rpm, before being returned to atmospheric pressure. The resulting polymer dispersion was pressure filtered through a 60-mesh filter to obtain an aqueous dispersion of ionomer.

[0103] <Evaluation of Aqueous Dispersions> In the following tests, the properties of aqueous dispersions obtained by the method described in <Preparation of Aqueous Dispersions 1> were evaluated as Examples 1 to 5. As comparative examples, aqueous dispersions of ionomers were prepared using commercially available branched-chain ionomer resins by the method described in <Preparation of Aqueous Dispersions 2: Direct Dispersion of Ionomers>. The resin used in Comparative Example 1 was "Hymiran® ​​1605" (manufactured by Mitsui Dow Polychemicals; metal species Na, degree of neutralization 30%, phase angle δ46°), and the resin used in Comparative Example 2 was "Hymiran® ​​1707" (manufactured by Mitsui Dow Polychemicals; metal species Na, degree of neutralization 54%, phase angle δ47°).

[0104] (1) Dispersibility ("Solubility") The obtained aqueous dispersion was placed in a 110 mL vial and allowed to stand. The state of the aqueous dispersion was visually checked, and those that were uniformly dispersed were deemed acceptable (○), while those that retained the shape of pellets or had lost their fluidity and become gel-like were deemed unacceptable (×). The results are shown in Table 2.

[0105] <Evaluation of Ionomers> In the following tests, the properties of the ionomer resin obtained by kneading with a Laboplastmill in <Production of Aqueous Dispersion 2> were evaluated. (2) MFR [g / 10 min], (3) Melting point (Tm [°C]), and (4) Abrasion amount [mg] were evaluated by the following methods. The results are shown in Table 2. (2) Melt flow rate (MFR) The MFR was measured at a temperature of 190°C and a load of 21.18 N (= 2.16 kg) according to Table 1 - Condition 7 of JIS K-7210 (1999). (3) Melting point (Tm [°C]) The melting point is indicated by the peak temperature of the endothermic curve measured by a differential scanning calorimeter (DSC). A DSC (DSC7020) manufactured by SII Nanotechnology Co., Ltd. was used for the measurement and was carried out under the following measurement conditions. Approximately 5.0 mg of the sample was placed in an aluminum pan, heated to 200°C at 10°C / min, held at 200°C for 5 minutes, and then cooled to 30°C at 10°C / min. After holding at 30°C for 5 minutes, the absorption curve was raised again at 10°C / min, and the maximum peak temperature was determined as the melting point Tm. (4) Measurement of wear amount 1) Method of preparing wear test samples The sample was placed in a heating press mold with dimensions of 150 mm x 150 mm and a thickness of 1 mm, preheated in a hot press machine at a surface temperature of 180°C for 5 minutes, and then melted by repeatedly applying and removing pressure, while degassing any residual gas in the sample. Further pressurization was applied at 4.9 MPa and held for 3 minutes. After that, while maintaining a pressure of 4.9 MPa, it was gradually cooled at a rate of 10°C / min, and the molded plate was removed from the mold when the temperature had dropped to around room temperature. The resulting molded plate was conditioned for 48 hours or more under conditions of 23±2°C temperature and 50±5°C humidity. After conditioning, the pressed plate was cut into a circle with a diameter of approximately 115 mm, and a hole with a diameter of approximately 6.5 mm was drilled in the center to serve as an abrasion test sample. 2) Abrasion test conditions Using the above test piece, the amount of abrasion loss (mg) was measured under the following conditions in accordance with JIS K 7204-1999. ・Equipment: Taber abrasion tester (rotary abrasion tester) - manufactured by Toyo Seiki Seisakusho Co., Ltd. ・Abrasion wheel: CS-17 ・Rotation speed: 60 rpm ・Number of tests: 1000 rpm ・Load: 4.9 N

[0106]

[0107] <Discussion of Examples / Comparative Examples> Examples 1 to 6 can produce aqueous dispersions that satisfy the constituent requirements of the present invention, and the samples obtained from such aqueous dispersions exhibit excellent wear resistance. On the other hand, Comparative Examples 1 and 2 consist of ionomers with a phase angle smaller than 50° and containing many long-chain branches, which do not satisfy the constituent requirements of the present invention, and therefore the improvement in wear resistance is insufficient.

[0108] <Production of Aqueous Dispersion 3> The method of Example 2 was scaled up to produce an aqueous dispersion for coating film evaluation in a 20 L autoclave. Each pelletized copolymer (3.6 kg) obtained in Production Example 4 was added to a 20 L autoclave equipped with a stirring blade along with ion-exchanged water (6 L), the autoclave was purged with nitrogen, and pressurized to 0.6 MPa. Subsequently, the internal temperature was heated to 130°C while stirring at 50 rpm. After confirming that stirring was being performed without excessive load, an amount of sodium hydroxide aqueous solution sufficient to achieve the predetermined degree of neutralization was pumped into the autoclave. At this time, if there was a possibility that the pellets would stick together and the stirring load would increase, stirring was temporarily stopped until the temperature reached 130°C, and after the resin melted, stirring was resumed. If the load on the stirring shaft did not decrease even after the temperature exceeded 130°C, stirring was resumed after adding sodium hydroxide aqueous solution. After confirming that the sodium hydroxide aqueous solution had been added and the reaction mixture was stirring, the mixture was stirred at 300 rpm for 2 hours. Then, while stirring at 300 rpm, the internal temperature was cooled to below 70°C at a rate of less than 1°C / min, and the mixture was returned to atmospheric pressure. The resulting dispersion was pressure filtered through a 60-mesh filter, and the dispersion was transferred to a poly tank (20 L). The filtration residue was collected along with the filter. The further filtered polymer dispersion was pressure filtered through a 300-mesh filter to obtain an aqueous dispersion.

[0109] <Coating Film Evaluation Test> In the coating film evaluation test, the aqueous dispersion obtained by the method described in <Production of Aqueous Dispersion 3> was used as a dispersion production example to evaluate the properties of the coating film. The comparative dispersion example was a commercially available branched-chain structure "Chemipearl (registered trademark) S100" (manufactured by Mitsui Dow Polychemicals: metal species Na, degree of neutralization 63%, phase angle δ47°).

[0110] <Manufacturing of the coating film> Several grams of the dispersion liquid were placed on a 0.8 mm thick aluminum-treated plate A1050P (TP Giken Co., Ltd.) that had been washed with xylene, and the coating was applied using a bar coater #16 (film thickness 24-32 μm / wet). The coating film was dried under two conditions: leaving it at room temperature and placing it in a drying oven set to 65°C for 30 minutes. After drying, the coating film was left at room temperature for more than one week to stabilize the surface, and then a coating film test was conducted.

[0111] <Observation of the coating surface> (1) Film formation The condition of the coating obtained in <Coating production> was visually checked, and coatings that were free of cracks and uniformly formed were deemed suitable for film formation (○), while coatings that were cracked and not formed were deemed unsuitable for film formation (×). (2) Surface roughness The surface of the coating was observed at an observation magnification of 50x using a laser microscope equipped with a white light interferometer (Keyence Corporation), and the surface roughness was measured.

[0112] <Mechanical Properties Evaluation of the Coating Surface> (1) Pencil Hardness The pencil hardness was measured using a pencil scratch hardness tester based on JIS K-5600 (pencil scratch test) and JIS K-5400. The test method involved scratching the coated surface at a 45° angle using 14 grades of pencils from 6B to 6H, and evaluating the pencil scratch value as the hardest pencil density symbol that did not leave any scratches on the coating. A 750g weight was used to confirm the pencil hardness at which scratches were made. The test was performed twice, and continued until the same result was obtained in the first and second measurements. (2) Adhesion For the adhesion test, a grid pattern (25 squares) was made in the coating using a utility knife. Cellophane tape was firmly pressed onto the grid pattern and then pulled off, and the adhesion was evaluated on a 6-point scale from the best classification 0 to the worst classification 5. (3) Measurement of wear amount 1) Method of preparing wear test samples Several grams of dispersion liquid were placed on a 0.5 mm thick, 100 mm square aluminum-treated plate A1050P that had been washed with xylene, and coated with a bar coater #16 (film thickness 24-32 μm / wet). Drying of the coating film was carried out under two conditions: leaving it at room temperature and placing it in a drying oven set to 65°C for 30 minutes. After drying, it was left at room temperature for more than one week to stabilize the coating film surface. 2) Wear test conditions Using the above test piece, the amount of wear loss (mg) was measured in accordance with JIS K 7204-1999 under the following conditions. ・Apparatus: Taber abrasion tester (rotary abrasion tester) - manufactured by Toyo Seiki Seisakusho Co., Ltd. ・Wear wheel: CS-17 ・Rotation speed: 60 rpm ・Number of tests: 50 rpm ・Load: 4.9 N

[0113] <Evaluation of coating adhesion> (1) Heat seal evaluation A dispersion was coated onto aluminum foil using a bar coater, and after drying, the substrate was cut into 25 mm wide strips. To bond the coated surfaces of these test pieces together, heat sealing was performed using a vacuum laminator. The vacuum laminator conditions were set to a heating temperature of 120°C, a chamber gauge pressure of -0.1 MPa, and a holding time of 60 seconds, and heat-pressed bonding was performed. After leaving the heat-sealed test pieces for one day, the adhesive strength of the aluminum foil was confirmed using a tensile Tensilon tester at a tensile speed of 50 mm / min.

[0114] <Evaluation of chemical properties of the coating surface> (1) Water resistance test The test coating plate was immersed in water for a specified time to evaluate whether any abnormalities such as blistering or peeling occurred in the coating. The test was conducted for 24 hours, and the condition of the coating was observed 1 hour after removal.

[0115]

[0116] <Consideration of Painting Examples / Comparative Examples> Painting Examples 1 and 2 can produce aqueous dispersions that satisfy the constituent requirements of the present invention, and the coating film produced from such aqueous dispersions exhibits excellent abrasion resistance under low drying conditions. On the other hand, Comparative Examples 1 and 2 are produced from aqueous dispersions containing ionomers with many long-chain branches and a phase angle smaller than 50°, which do not satisfy the constituent requirements of the present invention, and therefore the improvement in abrasion resistance is insufficient.

Claims

1. A resin for aqueous dispersions comprising an ionomer obtained by converting at least a portion of the carboxyl groups and / or dicarboxylic acid anhydride groups in a copolymer (P) that satisfies the following conditions (a) and (b), into a metal-containing carboxylate salt containing at least one metal ion selected from Group 1, 2, or 12 of the periodic table. (a) １３ (b) The number of methyl branches calculated by C-NMR is 50 or less per 1,000 carbon atoms. (b) The absolute value G of the complex modulus measured with a rotational rheometer. ＊ = The phase angle δ at 0.1 MPa is between 50 and 75 degrees.

2. The aqueous dispersion resin according to claim 1, characterized in that the copolymer (P) contains 2.0 to 20.0 mol% of the structural unit (B) in the copolymer.

3. The resin for aqueous dispersion according to claim 1, characterized in that the structural unit (A) is a structural unit derived from ethylene.

4. The aqueous dispersion resin according to claim 1, characterized in that the copolymer (P) is produced using a transition metal catalyst containing a transition metal of Group 8 to 11 of the periodic table.

5. The aqueous dispersion resin according to claim 4, characterized in that the transition metal catalyst is a transition metal catalyst comprising a phosphorusulfonic acid or phosphorphenol ligand and nickel or palladium.

6. The aqueous dispersion resin according to claim 1, wherein the copolymer (P) has a melt flow rate of 10 to 5000 g / 10 min, measured at a temperature of 190°C and a load of 2.16 kg.

7. An aqueous dispersion comprising the resin for aqueous dispersions and water according to any one of claims 1 to 6.

8. A method for producing an aqueous dispersion, comprising the step of mixing the resin for aqueous dispersions described in any one of claims 1 to 6 with water and stirring at a temperature of 50°C to 250°C.

9. A coating film formed using the aqueous dispersion described in claim 7.

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