Resin dispersion composition

Abstract

Provided are an aqueous dispersion composition containing, stably dispersed therein, a copolymer containing α,β unsaturated carboxylic acid or an ester thereof as a structural unit, the composition retaining both characteristics of the content of the copolymer being relatively high and the viscosity being relatively low; and a production method for the same.　The production method produces an aqueous dispersion composition of a copolymer containing α,β unsaturated carboxylic acid or an ester thereof as a structural unit, and comprises: (1) mixing a copolymer, which contains α,β unsaturated carboxylic acid or an ester thereof as a structural unit, a basic substance and water such that the concentration of the copolymer is 40-62 mass%, and the copolymer is neutralized to a neutralization degree of 10-35%; (2) pressurizing the obtained mixture at 0.1-2 MPa; and, if necessary, (3) adding water after the pressurization such that the concentration of the copolymer is adjusted to 30-60 mass%.

Description

Technical Field

[0001] The present disclosure relates to a resin dispersion composition and the like. The contents of all documents described in this specification are incorporated herein by reference.

Background Art

[0002] Certain resins (for example, ethylene / α,β-unsaturated carboxylic acid copolymers) can form films with good thermal adhesiveness, and thus are used in a wide range of applications such as coating agents, heat sealants, delay tackifiers, in-mold labels, percoat agents, fiber treatment agents, and various binders.

[0003] Resins used in such various applications may be used in a solid state or in a state dissolved or dispersed in a solvent or water. In the former case, as in the case of a laminate coating agent, it is difficult to form a thin film, and there has been a growing global demand to reduce plastics as much as possible in recent years. Therefore, it has become more common to use them in the latter state. Among those in the latter state, particularly from the viewpoints of resource saving, safety, and environmental problems, aqueous ones that do not require the use of a solvent, particularly those dispersed in water, have been increasingly demanded.

[0004] As a resin aqueous dispersion, for example, an aqueous dispersion obtained by neutralizing an ethylene / acrylic acid copolymer resin with a basic substance (ammonia, amine, or alkali metal hydroxide) is known (for example, Patent Documents 1 to 3).

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

[0006] For example, a method is known in which a resin having carboxyl groups (e.g., ethylene / α,β-unsaturated carboxylic acid copolymer) is dispersed at a temperature above the high-temperature melting point using a pressure-resistant homomixer or pressure-resistant colloid mill, while neutralizing the carboxyl groups with a basic substance.

[0007] When alkali metal salts are used as basic substances, ammonia is usually used in combination, and in order to maintain the stability of the resulting aqueous dispersion, the resin (polymer) content of the aqueous dispersion is low, for example, between 20% and 30% by mass. Furthermore, when ammonia is used alone as a basic substance, the amount used is larger compared to when neutralization is performed with amines or alkali metal salts, and as a result, the viscosity of the resulting aqueous dispersion tends to be very high or the stability to be poor.

[0008] Therefore, the present inventors conducted studies to develop an aqueous dispersion composition that stably contains a resin having carboxyl groups, and that also has the characteristics of having a relatively high copolymer content and a relatively low viscosity. [Means for solving the problem]

[0009] The inventors of the present invention conducted studies using ethylene / α,β-unsaturated carboxylic acid copolymers as an example of resins containing carboxyl groups. They found that aqueous dispersion compositions containing carboxyl group resins tend to have higher viscosity when the particle size of the resin is small. Therefore, in order to obtain an aqueous dispersion composition of the resin with relatively low viscosity, they attempted to prepare the resin with a large particle size.

[0010] In this experiment, the inventors found that reducing the amount of neutralizing agent (basic substance) used when preparing an aqueous dispersion composition of a resin having carboxyl groups tends to result in larger particle sizes of the resulting resin. Therefore, when they attempted to minimize the amount of neutralizing agent (basic substance) used when preparing an aqueous dispersion composition of a resin having carboxyl groups, they found that reducing the amount of neutralizing agent made it difficult for the resulting resin to disperse stably in an aqueous medium.

[0011] In other words, it became clear that reducing the amount of neutralizing agent used to prepare an aqueous dispersion composition of a resin having a carboxyl group, where the particle size is relatively large, results in poor dispersion stability.

[0012] To break through this impasse, further investigations revealed the possibility of preparing an aqueous dispersion composition containing a carboxyl group-containing resin (particularly a copolymer containing α,β-unsaturated carboxylic acid or its ester as a constituent unit) stably dispersed by increasing the internal pressure of a sealed pressure vessel used to neutralize the carboxyl group-containing resin (especially a copolymer containing α,β-unsaturated carboxylic acid or its ester as a constituent unit), and by appropriately adjusting the concentration of the copolymer in the copolymer-containing composition used for neutralization. This composition also possesses the characteristics of having a relatively high copolymer content and relatively low viscosity. Based on this finding, further improvements were made.

[0013] This disclosure includes, for example, the following subjects: Section 1. An aqueous dispersion composition of a copolymer containing an α,β-unsaturated carboxylic acid or its ester as a constituent unit, The polymer is contained in an amount of 30-60% by mass. The viscosity at 25°C is 5000 mPa·s or less. composition. Section 2. The α,β-unsaturated carboxylic acid is at least one selected from the group consisting of acrylic acid, methacrylic acid, crotonic acid, maleic acid, fumaric acid, and itaconic acid. The composition according to item 1, wherein the ester of the α,β-unsaturated carboxylic acid is an alkyl ester of the α,β-unsaturated carboxylic acid having 1 to 10 carbon atoms. Section 3. A copolymer containing an α,β-unsaturated carboxylic acid or its ester as a constituent unit, Furthermore, it is a copolymer containing at least one of ethylene, propylene, butene, isobutene, butadiene, isoprene, and styrene as a constituent unit. The composition described in item 1 or 2. Section 4. The composition according to any one of claims 1 to 3, wherein the degree of neutralization of a copolymer containing an α,β-unsaturated carboxylic acid or its ester as a constituent unit is 10 to 35%. Section 5. The composition according to any one of claims 1 to 4, wherein the median particle size of the copolymer containing an α,β-unsaturated carboxylic acid or its ester as a constituent unit is 1 to 10 μm. Section 6. The composition according to any one of claims 1 to 5, wherein the copolymer containing an α,β-unsaturated carboxylic acid or its ester as a constituent unit is an ethylene / α,β-unsaturated carboxylic acid copolymer. Section 7. The composition according to item 6, wherein the ethylene / α,β-unsaturated carboxylic acid copolymer is an ethylene / (meth)acrylic acid copolymer. Section 8. A laminate comprising a paper base and a coating on the paper base, The film is formed using any of the compositions described in items 1 to 7. Laminated structure. Section 9. (1) Mix a copolymer containing an α,β-unsaturated carboxylic acid or its ester as a constituent unit, a basic substance, and water such that the copolymer concentration is 40-62% by mass and the copolymer is neutralized to a degree of neutralization of 10-35%, and (2) Pressurize the resulting mixture to 0.1 to 2 MPa. including, A method for producing an aqueous dispersion composition of a copolymer containing an α,β-unsaturated carboxylic acid or its ester as a constituent unit. Item 10. (1a) A copolymer containing α,β-unsaturated carboxylic acid or its ester as a structural unit, ammonia, and water are The concentration of the copolymer is 40 to 62% by mass, Ammonia is 0.1 to 2 moles per mole of the carboxyl group contained in the copolymer, Mix them, and (2) Pressurize the obtained mixture at 0.1 to 2 MPa, including A method for producing an aqueous dispersion composition of a copolymer containing α,β-unsaturated carboxylic acid or its ester as a structural unit. Item 11. (1b) Ethylene / (meth)acrylic acid copolymer, ammonia, and water are The concentration of the copolymer is 40 to 62% by mass, Ammonia is at a concentration of 1 to 2% by mass, Mix them, and (2) Pressurize the obtained mixture at 0.1 to 2 MPa, including A method for producing an aqueous dispersion composition of an ethylene / (meth)acrylic acid copolymer. Item 12. Furthermore, (3) Further adding water after pressurization to adjust the copolymer concentration to 30 to 60% by mass, including The method for producing an aqueous dispersion composition according to any one of Items 9 to 11. Item 13. The production method according to any one of Items 9 to 12, wherein the aqueous dispersion composition is an aqueous dispersion composition having a viscosity of 5000 mPa·s or less at 25°C.

Advantages of the Invention

[0014] An aqueous dispersion composition stably containing a copolymer containing α,β-unsaturated carboxylic acid or its ester as a structural unit, having a relatively high content of the copolymer and also having a relatively low viscosity is provided. Also provided is a method for producing the aqueous dispersion composition.

[0015] Furthermore, this aqueous dispersion composition has the characteristic of requiring a relatively small amount of neutralizing agent (basic substance) in its preparation, resulting in a relatively small amount of neutralizing agent remaining in the aqueous dispersion composition. This aqueous dispersion composition can be used, for example, as a coating agent. Since a lower amount of basic substance improves the water resistance of the dried film of the aqueous dispersion composition, it is particularly preferable to use it as a paper coating agent for surfaces such as wallpaper, or as a food packaging coating agent.

[0016] Furthermore, because the aqueous dispersion composition contains a relatively high concentration of copolymers with α,β-unsaturated carboxylic acids or their esters as constituent units, it exhibits excellent film-forming properties. Moreover, depending on the material to which the aqueous dispersion composition is coated, such as paper, the penetration of the copolymer particles can be reduced, resulting in a thicker film, and thus reducing defects such as spots and holes after coating.

[0017] Furthermore, while high viscosity in a composition can make it difficult to handle and reduce workability, this aqueous dispersion composition has relatively low viscosity, making such problems less likely. [Modes for carrying out the invention]

[0018] The embodiments included in this disclosure will be described in more detail below. This disclosure preferably includes, but is not limited to, aqueous dispersion compositions of copolymers containing α,β-unsaturated carboxylic acids or their esters as constituent units and methods for producing the same, and this disclosure includes everything disclosed herein and that can be recognized by those skilled in the art. Copolymers containing α,β-unsaturated carboxylic acids or their esters as constituent units may be referred to as copolymer (A).

[0019] The aqueous dispersion compositions of copolymer (A) included in this disclosure contain 30% by mass or more (preferably 30-60% by mass) of copolymer (A) and have a viscosity of 5000 mPa·s or less at 25°C (more preferably 4500, 4000, 3500, 3000, 2500, 2000, 1500, or 1000 mPa·s or less). Hereinafter, the aqueous dispersion compositions included in this disclosure may be referred to as "the compositions of this disclosure".

[0020] The viscosity of the composition disclosed herein is measured using a BH-type rotational viscometer. Specifically, the viscosity is measured at 25°C with the spindle rotor rotation speed set to 60 revolutions per minute, by reading the viscosity value one minute after the rotor starts rotating. The rotor can be set appropriately according to the viscosity, and as a guideline, rotor No. 3 is used for viscosity less than 2000 mPa·s, rotor No. 4 for viscosity between 2000 mPa·s and 5000 mPa·s, rotor No. 5 for viscosity between 5000 mPa·s and 15000 mPa·s, rotor No. 6 for viscosity between 15000 mPa·s and 40000 mPa·s, and rotor No. 7 for viscosity of 40000 mPa·s or more.

[0021] Copolymer (A) is a copolymer containing one or more α,β-unsaturated carboxylic acids as constituent units, for example, (i) a copolymer of one or more α,β-unsaturated carboxylic acids or their esters with one or more monomers other than α,β-unsaturated carboxylic acids or their esters, or (ii) a copolymer of two or more α,β-unsaturated carboxylic acids or their esters. Note that "two or more α,β-unsaturated carboxylic acids or their esters" includes cases where only two or more α,β-unsaturated carboxylic acids are used, cases where only two or more α,β-unsaturated carboxylic acid esters are used, and cases where one or more α,β-unsaturated carboxylic acids and one or more α,β-unsaturated carboxylic acid esters are used.

[0022] Examples of α,β-unsaturated carboxylic acids include acrylic acid, methacrylic acid, crotonic acid, maleic acid, fumaric acid, and itaconic acid. Among these, (meth)acrylic acid (i.e., methacrylic acid and / or acrylic acid) is more preferred. Examples of esters of α,β-unsaturated carboxylic acids include alkyl esters having 1 to 10 carbon atoms (1, 2, 3, 4, 5, 6, 7, 8, 9, or 10). The alkyl portion of the alkyl ester may be linear or branched. More specifically, examples of esters of α,β-unsaturated carboxylic acids include methyl esters, ethyl esters, butyl (especially n-butyl) esters, and 2-ethylhexyl esters. Other examples of esters of α,β-unsaturated carboxylic acids include 2-methylaminoethyl esters and hydroxyethyl esters (especially 2-hydroxyethyl esters). Among the α,β-unsaturated carboxylic acid esters, methyl (meth)acrylate, ethyl (meth)acrylate, and butyl (meth)acrylate are more preferred.

[0023] Examples of monomers other than α,β-unsaturated carboxylic acids or their esters include ethylene, propylene, butene, isobutene, butadiene, isoprene, and styrene.

[0024] More specifically, preferred copolymers (A) include, for example, copolymers of ethylene / α,β-unsaturated carboxylic acid or its ester, and copolymers of styrene / α,β-unsaturated carboxylic acid or its ester. Among these, ethylene / α,β-unsaturated carboxylic acid copolymers are more preferred. Even more specifically, for example, ethylene / (meth)acrylic acid copolymers, styrene / (meth)acrylic acid ester copolymers, and styrene / (meth)acrylic acid / (meth)acrylic acid ester copolymers are even more preferred. In particular, ethylene / α,β-unsaturated carboxylic acid copolymers are preferred.

[0025] Copolymer (A) can be prepared by known methods or by methods readily conceivable from known methods. Alternatively, commercially available products can be purchased and used. For example, commercially available ethylene / α,β-unsaturated carboxylic acid copolymers can be purchased and used. Examples of commercially available products include Primacol 5980, Primacol 5990 (manufactured by Dow Chemical Japan Ltd.), Nucrel AN4221C, Nucrel N5130H, Nucrel N2060, Nucrel N2050H, and Nucrel N1560 (manufactured by Mitsui DuPont Polychemical Co., Ltd.).

[0026] As the ethylene / α,β-unsaturated carboxylic acid copolymer, ethylene / (meth)acrylic acid copolymer is particularly preferred.

[0027] The copolymer (A) is not particularly limited, but it is preferable that the carboxyl groups (derived from α,β-unsaturated carboxylic acids) contained therein are moderately neutralized.

[0028] Typically, when the carboxyl groups of copolymer (A) are in a free state, the hydrophilicity is relatively low, while when the carboxyl groups are in a salt state, the hydrophilicity is relatively high. Therefore, by neutralizing with a base, the neutralized carboxyl groups in the copolymer act as emulsifiers, making it possible to produce an aqueous dispersion relatively easily.

[0029] Suitable bases for neutralization include, for example, ammonia, organic amines, or alkali metal hydroxides.

[0030] Examples of organic amines include methylamine, ethylamine, diethylamine, diethanolamine, and triethanolamine. Examples of alkali metal hydroxides include sodium hydroxide, potassium hydroxide, and lithium hydroxide. Furthermore, ammonia can be used in the form of ammonia gas or aqueous ammonia solution. These bases can be used individually or in combination of two or more. Among these, ammonia is preferred.

[0031] The copolymer (A) contained in the composition of this disclosure preferably has 10 to 35% of its carboxyl groups neutralized. That is, the degree of neutralization of the ethylene / α,β-unsaturated carboxylic acid copolymer is preferably 10 to 35%. The upper or lower limit of this range may be, for example, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, or 34%. For example, it may be 12 to 33%. The percentages are in mole percent of carboxyl group units.

[0032] Furthermore, although not particularly limited, the copolymer (A) is preferably one in which the α,β-unsaturated carboxylic acid content is, for example, 8% by mass or more, and more preferably 8 to 50% by mass. The upper or lower limit of this range may be, for example, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, or 49% by mass. For example, it may be 9 to 49% by mass. Note that the α,β-unsaturated carboxylic acid content here refers to the content of units derived from α,β-unsaturated carboxylic acid.

[0033] In particular, when copolymer (A) is an ethylene / α,β-unsaturated carboxylic acid copolymer, it is preferable that the α,β-unsaturated carboxylic acid content be 8 to 24% by mass in order to balance the nonpolar properties derived from the ethylene units with the polar properties derived from the α,β-unsaturated carboxylic acid. The upper or lower limit of this range may be, for example, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, or 23% by mass. The range may be, for example, 18 to 23% by mass. When the α,β-unsaturated carboxylic acid content is 8% by mass or more, the dispersibility in aqueous dispersion media is further improved due to the nonpolar properties derived from the ethylene units, and a superior aqueous dispersion composition can be efficiently obtained. Furthermore, when the α,β-unsaturated carboxylic acid content is less than 24% by mass, the blocking resistance of the film (coating film) prepared when the resulting aqueous dispersion composition is used as a coating agent is further improved.

[0034] The median particle size of copolymer (A) in the composition of this disclosure is preferably 1 to 10 μm. The upper or lower limit of this range may be, for example, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, or 9.5 μm. For example, the range may be 1.5 to 9.5 μm. A median particle size of 1 μm or more may result in a more desirable viscosity (not becoming too high) for the aqueous dispersion composition. Furthermore, a median particle size of 10 μm or less may improve the stability of the aqueous dispersion composition (i.e., the dispersed state of copolymer (A) may be more stable).

[0035] The median particle size is the median diameter and is a value measured by laser diffraction particle size distribution analysis. That is, it is the value obtained when an aqueous dispersion composition of copolymer (A) is measured using a laser diffraction particle size distribution analyzer. An example of such an analyzer is the SALD2300 manufactured by SHIMADZU. More specifically, 20 ml of water and 0.1 g of an anionic surfactant (such as polyoxyethylene lauryl sulfate ammonium, polyoxyalkylene alkyl ether sulfate sodium, etc.) are mixed, and 0.1 g of the aqueous dispersion composition of copolymer (A) to be measured is added to this mixture. Ultrasonic waves are applied for 3 minutes while stirring, and the measurement is performed using a laser diffraction particle size distribution analyzer. Note that particles that show the same diffraction and scattering light pattern as a sphere with a diameter of X μm are calculated as having a particle size of X μm regardless of their shape.

[0036] The copolymer (A) content in the composition of the present disclosure is preferably, for example, 30 to 60% by mass. The upper or lower limit of this range may be, for example, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, or 59% by mass. For example, the range may be 35 to 55% by mass.

[0037] Copolymer (A) can be used alone or in combination of two or more types.

[0038] Water is preferred as the aqueous medium for the compositions of this disclosure, and various types of water can be used, such as tap water, industrial water, ion-exchanged water, deionized water, and pure water. Deionized water or pure water is particularly preferred.

[0039] Furthermore, the compositions disclosed herein may contain other components as long as they do not impair the effects. For example, they may contain defoaming agents, viscosity modifiers, pH adjusters, surfactants, fungicides, etc., and optionally antioxidants, fatty acid amides, waxes, blocking agents such as silicone oils, alcohols, etc.

[0040] The compositions of this disclosure are useful, for example, as binders and coatings. The compositions of this disclosure can be applied to a base and dried to form a film. The base is preferably paper, and more preferably food and beverage packaging paper. The film prevents food and beverages from coming into direct contact with the paper (packaging paper). Furthermore, the film is preferable because it has little adverse effect on food and beverages.

[0041] The disclosure also preferably includes laminates comprising, for example, a paper substrate and a film on the paper substrate, wherein the film is formed using the composition of the disclosure.

[0042] The compositions of this disclosure can be prepared, for example, by mixing a copolymer (A), a basic substance, and water such that the copolymer is neutralized to a specific concentration and degree of neutralization, and then pressurizing (and further heating if necessary). After pressurizing, it is more preferable to further dilute the copolymer with water to a specific concentration.

[0043] In the mixing of copolymer (A), a basic substance, and water, the concentration of copolymer (A) is preferably 40 to 62% by mass. The upper or lower limit of this concentration range may be, for example, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, or 61% by mass. For example, the concentration range may be, for example, 40 to 55% by mass or 45 to 55% by mass.

[0044] Furthermore, as described above, the degree of neutralization of copolymer (A) contained in the composition of this disclosure is preferably 10 to 35%, and in the mixing here, it is preferable that the basic substance is mixed so that copolymer (A) is neutralized to a degree of neutralization of 10 to 35%.

[0045] More specifically, for example, when using an ethylene / (meth)acrylic acid copolymer as copolymer (A) and ammonia as the basic substance, it is preferable to mix the ethylene / (meth)acrylic acid copolymer with water so that its concentration in the resulting mixture is 40-62% by mass, and the ammonia so that the degree of neutralization of the copolymer is 10-35%. The amount of ammonia is not particularly limited as long as it is within the range that the degree of neutralization can be achieved, but for example, the concentration of ammonia in the resulting mixture is preferably 1-2% by mass. Furthermore, the amount of ammonia used is preferably 0.1-2 moles, and more preferably 0.4-1 mole, per mole of carboxyl groups contained in the ethylene / α,β-unsaturated carboxylic acid copolymer. It is preferable to mix the ammonia by mixing with ammonia water.

[0046] The mixture obtained by mixing copolymer (A), a basic substance, and water is pressurized. Preferably, the mixture is pressurized while being mixed (e.g., stirred). The pressurization is preferably about 0.1 to 2 MPa. The upper or lower limit of this range may be, for example, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, or 1.9 MPa. For example, the range may be 0.2 to 1.5 MPa.

[0047] Pressurization can be carried out, for example, by placing the mixture in a sealed, agitable pressure-resistant container and then introducing an inert gas into the container. Examples of inert gases include nitrogen gas. Examples of such containers include a pressure-resistant autoclave equipped with a stirrer.

[0048] Furthermore, it is preferable to heat the mixture as needed during the pressurization process. For example, it is preferable to heat the mixture to a temperature above the temperature at which copolymer (A) softens in an aqueous medium. More specifically, it is preferable to heat it to about 90-150°C, and more preferably to about 95-140°C. If copolymer (A) is an ethylene / (meth)acrylic acid copolymer, it is particularly desirable to heat it to this temperature and allow it to mature.

[0049] After cooling, it is preferable to return to atmospheric pressure and, if necessary, add water to the resulting mixture to adjust it so that the mixture contains 30 to 60% by mass of copolymer (A). If the mixture was heated during pressurization, it is preferable to first cool it to 90°C or below (for example, 90 to 80°C), release the pressure in the container to return to atmospheric pressure, and add more water if necessary. When adding water, it is preferable to adjust the amount of water so that the copolymer (A) content in the mixture is 30 to 60% by mass. It is also preferable to mix (stir) the mixture as necessary.

[0050] By following the above steps, it is possible to obtain an aqueous dispersion composition in which copolymer (A) is stably dispersed, having a viscosity of 5000 mPa·s or less at 25°C (more preferably 4500, 4000, 3500, 3000, 2500, 2000, 1500, or 1000 mPa·s or less).

[0051] In addition, surfactants can be used in the manufacturing process, particularly to aid dispersion. However, according to this disclosure, an aqueous dispersion composition containing copolymer (A) in a stable dispersion is provided without the use of surfactants, and the composition also has the characteristics of having a relatively high copolymer content and a relatively low viscosity.

[0052] In this specification, the term "comprising" includes both "consisting essentially of" and "consisting of." Furthermore, this disclosure encompasses all any combination of the constituent elements described herein.

[0053] Furthermore, the various characteristics (properties, structure, function, etc.) described in each embodiment of this disclosure above may be combined in any way to identify the subject matter covered by this disclosure. In other words, this disclosure covers all subject matter consisting of any combination of the combinable characteristics described herein. [Examples]

[0054] The embodiments of this disclosure will be described in more detail below with examples, but the embodiments of this disclosure are not limited to the examples below.

[0055] <Method for measuring the median particle size> The median particle size of the resin (a copolymer containing α,β-unsaturated carboxylic acid or its ester as constituent units) in the aqueous dispersion composition was measured by mixing 20 ml of water and 0.1 g of an anionic surfactant (a synthetic detergent containing polyoxyethylene lauryl sulfate ammonium and polyoxyalkylene alkyl ether sulfate sodium) in a 100 ml beaker, adding 0.1 g of the sample (aqueous dispersion composition), stirring with a spatula, applying ultrasonic waves for 3 minutes, and measuring with a laser diffraction particle size analyzer (SHIMADZU SALD2300).

[0056] <Viscosity measurement method> The aqueous dispersion composition was immersed in a constant-temperature water bath maintained at 25°C, and the viscosity of the aqueous dispersion at 25°C was measured. Viscosity was measured using a Brookfield DV-II+ with rotor No. 3 and a predetermined rotation speed. The rotational speeds in each example are shown in Table 1 below.

[0057] [Table 1]

[0058] <Solid content (mass%) measurement method> One g of the aqueous dispersion composition was weighed and dried in a hot air dryer (ADVANTEC DRE320DR) at 130°C for 3 hours to obtain the dried solid. The solid content (mass %) was calculated using the following formula.

[0059]

number

[0060] <Residue (mass%) measurement method> The contents of the composition obtained after neutralization of a copolymer containing α,β-unsaturated carboxylic acid or its ester as a constituent unit were filtered through an 80-mesh polyethylene sieve, and the weight of the filtration residue remaining on the 80-mesh sieve was confirmed. The residue (mass%) was calculated using the following formula.

[0061]

number

[0062] In the following example, an ethylene / α,β-unsaturated carboxylic acid copolymer was used as the copolymer containing α,β-unsaturated carboxylic acid or its ester as a constituent unit.

[0063] (Example 1) 200g of ethylene / α,β-unsaturated carboxylic acid copolymer (EAA (ethylene / acrylic acid copolymer); product name Primacol 5980, acrylic acid content 20%, manufactured by LG Global), 8.4g of 28% aqueous ammonia as a neutralizing agent, and 191.6g of water were charged into a 1000mL pressure vessel equipped with a stirrer, and the vessel was sealed. Subsequently, nitrogen gas was introduced and the vessel was pressurized to 0.5MPa using the pressure gauge installed in the pressure vessel. Then, the temperature was raised to 130°C while stirring at 200 rpm, and the contents of the vessel were stirred at 130°C for 4 hours. Next, the contents were cooled to 90°C while stirring at 100 rpm, the remaining pressure inside the vessel was leaked back to atmospheric pressure, 100g of water was added through the side tube of the vessel for dilution, and the contents were cooled to 50°C. The contents were filtered through an 80-mesh polyethylene screen to obtain an aqueous dispersion. The resulting aqueous dispersion composition had a solid content of 39.8% by mass, a median particle size of 4 μm, a viscosity of 50 mPa·s, and a residue content of 1.0% by mass or less.

[0064] (Example 2) 200g of ethylene / α,β-unsaturated carboxylic acid copolymer (EAA (ethylene / acrylic acid copolymer); product name Primacol 5980, acrylic acid content 20%, manufactured by LG Global), 8.8g of 28% aqueous ammonia as a neutralizing agent, and 191.2g of water were charged into a 1000mL pressure vessel equipped with a stirrer, and the vessel was sealed. Subsequently, nitrogen gas was introduced and the pressure was increased to 0.5MPa using the pressure gauge installed in the pressure vessel. Then, the temperature was raised to 130°C while stirring at 200 rpm, and the contents of the vessel were stirred at 130°C for 4 hours. Next, the contents were cooled to 90°C while stirring at 100 rpm, the remaining pressure inside the vessel was leaked back to atmospheric pressure, 50g of water was added through the side tube of the vessel for dilution, and the contents were cooled to 50°C. The contents were filtered through an 80-mesh polyethylene screen to obtain an aqueous dispersion. The resulting aqueous dispersion composition had a solid content of 44.9% by mass, a median particle size of 4 μm, a viscosity of 300 mPa·s, and a residue content of 1.0% by mass or less.

[0065] (Comparative Example 1) 240g of ethylene / α,β-unsaturated carboxylic acid copolymer (EAA (ethylene / acrylic acid copolymer); product name Primacol 5980, acrylic acid content 20%, manufactured by LG Global), 11.0g of 28% aqueous ammonia as a neutralizing agent, and 129.0g of water were charged into a 1000mL pressure vessel equipped with a stirrer, and the vessel was sealed. Subsequently, nitrogen gas was introduced and the pressure was increased to 0.5MPa using the pressure gauge installed in the pressure vessel. Then, the temperature was raised to 130°C while stirring at 200 rpm, and the contents of the vessel were stirred at 130°C for 4 hours. Next, the contents were cooled to 90°C while stirring at 100 rpm, the remaining pressure inside the vessel was leaked back to atmospheric pressure, 250g of water was added through the side tube of the vessel for dilution, and the contents were cooled to 50°C. An attempt was made to filter the dissolved substance, but due to its high viscosity, it was difficult, and an aqueous dispersion was obtained without filtration. The resulting aqueous dispersion composition had a medium particle size of 0.1 μm and a viscosity of 16,000 mPa·s.

[0066] (Comparative Example 2) 200g of ethylene / α,β-unsaturated carboxylic acid copolymer (EAA (ethylene / acrylic acid copolymer); product name Primacol 5980, acrylic acid content 20%, manufactured by LG Global), 13.5g of 28% aqueous ammonia as a neutralizing agent, and 186.5g of water were charged into a 1000mL pressure vessel equipped with a stirrer, and the vessel was sealed. Subsequently, nitrogen gas was introduced and the pressure was increased to 0.5MPa using the pressure gauge installed in the pressure vessel. Then, the temperature was raised to 130°C while stirring at 200 rpm, and the contents of the vessel were stirred at 130°C for 4 hours. Next, the contents were cooled to 90°C while stirring at 100 rpm, the remaining pressure inside the vessel was leaked back to atmospheric pressure, 100g of water was added through the side tube of the vessel to dilute the solution, and the contents were cooled to 50°C. An attempt was made to filter the dissolved substance, but due to its high viscosity, it was difficult, and an aqueous dispersion was obtained without filtration. The resulting aqueous dispersion composition had a medium particle size of 0.2 μm and a viscosity of 100,000 mPa·s.

[0067] (Comparative Example 3) 200g of ethylene / α,β-unsaturated carboxylic acid copolymer (EAA (ethylene / acrylic acid copolymer); product name Primacol 5980, acrylic acid content 20%, manufactured by LG Global), 6.7g of 28% aqueous ammonia as a neutralizing agent, and 193.3g of water were added and the container was sealed. Subsequently, nitrogen gas was introduced and the container was pressurized to 0.5MPa using the pressure gauge attached to the container. Then, the temperature was raised to 130°C while stirring at 200 revolutions per minute, and the contents of the container were stirred at 130°C for 4 hours. Next, the contents were cooled to 90°C while stirring at 100 revolutions per minute, the remaining pressure inside the vessel was leaked back to atmospheric pressure, 100g of water was added through the side tube of the container for dilution, and the contents were cooled to 50°C. Upon inspection of the contents, the resin remained intact and was in an undispersed state.

[0068] (Comparative Example 4) 200 g of ethylene / α,β-unsaturated carboxylic acid copolymer (EAA (ethylene / acrylic acid copolymer); product name Primacol 5980, acrylic acid content 20%, manufactured by LG Global), 8.8 g of 28% aqueous ammonia as a neutralizing agent, and 191.2 g of water were charged into a 1000 mL pressure vessel equipped with a stirrer, and the vessel was sealed. The mixture was then heated to 130°C while stirring at 200 rpm, and the contents were stirred at 130°C for 4 hours. Next, the mixture was cooled to 90°C while stirring at 100 rpm, the remaining pressure inside the vessel was leaked back to atmospheric pressure, 100 g of water was added through the side tube of the vessel for dilution, and the mixture was cooled to 50°C. The contents were filtered through an 80-mesh polyethylene screen to obtain an aqueous dispersion. The obtained aqueous dispersion had a solid content of 40% by mass, a median particle size of 3 μm, a liquid viscosity of 135 mPa·s, and a residue of 20% by mass or less.

[0069] (Comparative Example 5) 160g of ethylene / α,β-unsaturated carboxylic acid copolymer (EAA (ethylene / acrylic acid copolymer); product name Primacol 5980, acrylic acid content 20%, manufactured by LG Global), 10.5g of 28% aqueous ammonia as a neutralizing agent, and 229.5g of water were charged into a 1000mL pressure vessel equipped with a stirrer and sealed. Subsequently, nitrogen gas was introduced and pressurized to 0.5MPa using a pressure gauge attached to the pressure vessel. Then, the temperature was raised to 130°C while stirring at 200 rpm, and the contents of the vessel were stirred at 130°C for 4 hours. Next, the contents were cooled to 90°C while stirring at 100 rpm, the remaining pressure inside the vessel was leaked back to atmospheric pressure, and the contents were cooled to 50°C. An attempt was made to filter the dissolved material, but due to its high viscosity, it was difficult, and an aqueous dispersion was obtained without filtration. The obtained aqueous dispersion composition had a median particle size of 9.5 μm and a liquid viscosity of 17000 mPa·s.

[0070] The results are summarized in Table 2. In the table, the resin refers to ethylene / α,β-unsaturated carboxylic acid copolymer (specifically, ethylene / acrylic acid copolymer). The solid content concentration (mass%) in these examples can be said to be the concentration of ethylene / α,β-unsaturated carboxylic acid copolymer in the aqueous dispersion composition.

[0071] [Table 2]

Claims

1. An aqueous dispersion composition of a copolymer containing an α,β-unsaturated carboxylic acid or its ester as a constituent unit, A copolymer containing the α,β-unsaturated carboxylic acid or its ester as a constituent unit, Furthermore, it is a copolymer containing at least one of ethylene, propylene, butene, isobutene, butadiene, and isoprene as a constituent unit. The copolymer is contained in an amount of 30 to 60% by mass. The median particle size of the copolymer is 1 to 10 μm. The viscosity at 25°C is 2000 mPa·s or less. composition.

2. The α,β-unsaturated carboxylic acid is at least one selected from the group consisting of acrylic acid, methacrylic acid, crotonic acid, maleic acid, fumaric acid, and itaconic acid. The composition according to claim 1, wherein the ester of the α,β-unsaturated carboxylic acid is an alkyl ester of an α,β-unsaturated carboxylic acid having 1 to 10 carbon atoms.

3. The composition according to claim 1 or 2, wherein the degree of neutralization of the copolymer containing an α,β-unsaturated carboxylic acid or its ester as a constituent unit is 22 to 35%.

4. The composition according to any one of claims 1 to 3, wherein the copolymer containing an α,β-unsaturated carboxylic acid or its ester as a constituent unit is an ethylene / α,β-unsaturated carboxylic acid copolymer.

5. The composition according to claim 4, wherein the ethylene / α,β-unsaturated carboxylic acid copolymer is an ethylene / (meth)acrylic acid copolymer.

6. A laminate comprising a paper base and a coating on the paper base, A laminate in which the coating is formed using the composition described in any one of claims 1 to 5.

7. (1) Mix a copolymer containing an α,β-unsaturated carboxylic acid or its ester as a constituent unit, a basic substance, and water such that the copolymer concentration is 40 to 62% by mass and the copolymer is neutralized to a degree of neutralization of 22 to 35%, and (2) Pressurize the resulting mixture to 0.2 to 2 MPa. including, A method for producing an aqueous dispersion composition of a copolymer containing an α,β-unsaturated carboxylic acid or its ester as a constituent unit.

8. (1b) Ethylene / (meth)acrylic acid copolymer, ammonia, and water The copolymer has a concentration of 40 to 62% by mass. The ammonia should be added so that its concentration is 1-2% by mass. Mixing, and (2) Pressurize the resulting mixture to 0.2 to 2 MPa. including, A method for producing an aqueous dispersion composition of an ethylene / (meth)acrylic acid copolymer.

9. moreover, (3) After pressurizing, water is added to adjust the copolymer concentration to 30 to 60% by mass, A method for producing the aqueous dispersion composition according to claim 7 or 8.

10. The manufacturing method according to any one of claims 7 to 9, wherein the aqueous dispersion composition is an aqueous dispersion composition having a viscosity of 2000 mPa·s or less at 25°C.

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