Aqueous resin dispersion liquid and application using the same

Abstract

To provide an aqueous resin dispersion liquid in which a film obtained from the aqueous resin dispersion liquid containing an aliphatic polyester-based resin can achieve both heat sealability and durability against water.SOLUTION: An aqueous resin dispersion liquid (I) contains a dispersoid (A) containing an aliphatic polyester-based resin (a), a non-ionic dispersion agent (B), and a dispersion medium (C), wherein a melt flow rate (MFR) of the dispersoid (A) at 190°C and a load of 2.16 kg is less than 15 g / 10 min, and a content of the non-ionic dispersion agent (B) is 0.1 pt.mass or more and less than 10 pts.mass with respect to 100 pts.mass of the dispersoid (A).SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to an aqueous resin dispersion, and more particularly to a coating agent, a molded article, a film, a cosmetic, an agricultural composition, a paint, an ink, and a pressure-sensitive adhesive using the same. [Background technology]

[0002] Conventionally, aqueous resin dispersions in which resins are dispersed in aqueous media have been used in various fields and applications, such as coating agents, cosmetics, paints, etc. Among them, polyester-based resins can be made into biodegradable resins or produced from bio-based raw materials, and can be used in response to the recent trend for environmentally friendly materials, and therefore are utilized in various fields and applications.

[0003] For example, as an aqueous resin dispersion having excellent biodegradability, an aqueous resin dispersion composition has been proposed in which an aliphatic polyester resin such as polylactic acid or polybutylene succinate is emulsified using a dispersant such as polyvinyl alcohol, and it is expected that the composition will be used in various applications such as adhesives, paints, and coating agents (e.g., Patent Document 1).

[0004] Furthermore, Patent Document 2 discloses that by using a polycaprolactone resin and setting the mass ratio of a nonionic dispersant to a biodegradable resin within a specific range, a transparent coating can be obtained without carrying out a special heat treatment.

[0005] However, some aqueous resin dispersions containing aliphatic polyester resins have insufficient stability. Therefore, it has been found that by blending a specific plasticizer, an aqueous resin dispersion having excellent stability can be obtained, and an aqueous resin dispersion composition having excellent film-forming properties and heat sealability can be obtained (for example, Patent Document 3). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2004-204038 A [Patent Document 2] Patent Publication No. 2022-60830 [Patent Document 3] JP 2022-167851 A Summary of the Invention [Problem to be solved by the invention]

[0007] However, in the techniques disclosed in Patent Documents 1 to 3, the compatibility between the heat sealability and water durability of the coating obtained from the aqueous resin dispersion has not been fully examined, and there is still room for improvement. The present invention has been made in consideration of the above-mentioned problems, and an object of the present invention is to provide an aqueous resin dispersion containing an aliphatic polyester-based resin, which can produce a coating having both heat sealability and durability against water. [Means for solving the problem]

[0008] In light of these circumstances, the inventors conducted extensive research and discovered that a coating obtained from an aqueous resin dispersion containing a dispersoid with a specific melt flow rate (MFR) that includes an aliphatic polyester resin and a specific amount of a nonionic dispersant can achieve both heat sealability and durability against water, thereby completing the present invention.

[0009] The gist of the present invention lies in the following [1] to

[19] . [1] An aqueous resin dispersion (I) comprising a dispersoid (A) containing an aliphatic polyester resin (a), a nonionic dispersant (B), and a dispersion medium (C), wherein the dispersoid (A) has a melt flow rate (MFR) of less than 15 g / 10 min at 190°C under a load of 2.16 kg, and the content of the nonionic dispersant (B) is 0.1 parts by mass or more and less than 10 parts by mass per 100 parts by mass of the dispersoid (A).

[0010] [2] The aqueous resin dispersion according to [1], wherein the aliphatic polyester resin (a) has a melt flow rate (MFR) of 100 g / 10 min or less at 190° C. under a load of 2.16 kg. [3] The aqueous resin dispersion according to [1], wherein the aliphatic polyester resin (a) is polybutylene succinate and / or polybutylene succinate adipate. [4] The aqueous resin dispersion according to [1], wherein the nonionic dispersant (B) is a polyvinyl alcohol-based resin. [5] The aqueous resin dispersion according to [1] or [2], wherein the nonionic dispersant (B) is an unmodified polyvinyl alcohol resin.

[0011] [6] The aqueous resin dispersion according to [4], wherein the polyvinyl alcohol-based resin has a degree of saponification of 70 to 90 mol %. [7] The aqueous resin dispersion according to [4], wherein the polyvinyl alcohol-based resin has an average degree of polymerization of 1,000 to 3,000. [8] The aqueous resin dispersion according to [4], wherein the polyvinyl alcohol-based resin has a 4 mass % aqueous solution viscosity at 20° C. of 2 to 70 mPa s. [9] The aqueous resin dispersion according to [1], wherein the dispersion medium (C) is water.

[0012]

[10] A coating agent comprising the aqueous resin dispersion according to [1].

[11] The coating agent according to

[10] , wherein the substrate to be coated is a paper substrate.

[12] The coating agent according to

[10] , wherein the object to be coated is a plastic substrate.

[13] A molded article obtained by using the aqueous resin dispersion according to [1] or [2].

[14] A film obtained by using the aqueous resin dispersion according to [1] or [2].

[15] A cosmetic preparation comprising the aqueous resin dispersion according to [1] or [2].

[16] An agricultural composition comprising the aqueous resin dispersion according to [1] or [2].

[17] A paint containing the aqueous resin dispersion according to [1] or [2].

[18] An ink containing the aqueous resin dispersion according to [1] or [2].

[19] A pressure-sensitive adhesive comprising the aqueous resin dispersion according to [1] or [2]. Effect of the Invention

[0013] According to the present invention, it is possible to provide an aqueous resin dispersion containing an aliphatic polyester resin, which enables a film obtained from the aqueous resin dispersion to have both heat sealability and durability against water. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] The present invention will be described in more detail below based on the embodiments of the present invention, but the present invention is not limited to these embodiments. In this specification, when an expression is made such as "X to Y" (X and Y are arbitrary numbers), it means "X or more and Y or less" unless otherwise specified. Furthermore, "X and / or Y (X and Y are optional)" means at least one of X and Y, and means the following three cases: X only, Y only, and X and Y.

[0015] An aqueous resin dispersion according to one embodiment of the present invention is an aqueous resin dispersion containing a dispersoid (A) and a nonionic dispersant (B), and further containing a dispersion medium (C). Such an aqueous resin dispersion is obtained by a known production method such as a phase inversion emulsification method using the dispersoid (A) according to one embodiment of the present invention.

[0016] [Dispersoid (A)] The dispersoid (A) is not particularly limited as long as it contains the aliphatic polyester resin (a) described below, and may contain other resins and additives. Examples of other resins include acrylic resins, urethane resins, natural rubber, and olefin resins. Examples of the olefin resin include binary or ternary random copolymers of ethylene and α,β-unsaturated carboxylic acids, such as ethylene-(meth)acrylic acid copolymer, ethylene-(meth)acrylic acid ester-(meth)acrylic acid copolymer, ethylene-vinyl acetate-(meth)acrylic acid copolymer, and ethylene-(meth)acrylic acid ester-maleic anhydride copolymer; and copolymers of polyethylene, ethylene and α-olefins such as propylene, ethylene-vinyl acetate copolymer, and ethylene-(meth)acrylic acid ester copolymer, which are graft-copolymerized with (meth)acrylic acid, maleic anhydride, or the like. Examples of the additive include a plasticizer and a wax.

[0017] The proportion of the aliphatic polyester resin (a) in the dispersoid (A) is not particularly limited, but is preferably 10% by mass or more, more preferably 50% by mass or more, and even more preferably 80% by mass or more.

[0018] The melt flow rate (MFR) of the dispersoid (A), measured at 190° C. and 2.16 kg, is less than 15 g / 10 min, preferably 10 g / 10 min or less, more preferably 6 g / 10 min or less, and the lower limit is usually 0.1 g / 10 min or more, preferably 1 g / 10 min or more, more preferably 2 g / 10 min or more, and even more preferably 3 g / 10 min or more. By setting the MFR within the above range, the effects of the present invention can be obtained.

[0019] The melting point of the dispersoid (A) is not particularly limited, but is preferably 110°C or less, more preferably 108°C or less, and even more preferably 105°C or less. If the melting point is within the above range, the production of the aqueous resin dispersion tends to be easy in the phase inversion emulsification step of mixing with a dispersion medium, and the stability of the obtained aqueous resin dispersion tends to be high. The lower limit of the melting point is not particularly limited, but is, for example, about 70°C.

[0020] [Aliphatic polyester resin (a)] The aliphatic polyester resin (a) (hereinafter sometimes referred to as "component (a)") is not particularly limited as long as the molar ratio of the aliphatic structure (including alicyclic structure) is the maximum ratio relative to the total polyester resin constituting the dispersoid (A), and may be, for example, an aliphatic-aromatic polyester resin having a partial aromatic structure in addition to the aliphatic structure. Specific examples of the component (a) include aliphatic polyester resins (a1) having aliphatic diol units and aliphatic dicarboxylic acid units as the main structural units (hereinafter, sometimes referred to as "component (a1)"); aliphatic polyester resins (a2) having aliphatic oxycarboxylic acid units as the main structural units (hereinafter, sometimes referred to as "component (a2)"); aliphatic aromatic polyester resins (a3) ​​having aliphatic diol units, aliphatic dicarboxylic acid units, and aromatic dicarboxylic acid units as the main structural units (hereinafter, sometimes referred to as "component (a3)"); and mixtures thereof. Among these, aliphatic polyester resins (a1) having aliphatic diol units and aliphatic dicarboxylic acid units as the main structural units are preferred.

[0021] Here, the term "unit" refers to a structural unit contained in the aliphatic polyester resin derived from a monomer component used in the production of the aliphatic polyester resin, and the term "main structural unit" refers to a structural unit derived from the target monomer component that is contained in the total structural units of the aliphatic polyester resin at 50 mol% or more. The content of the structural unit derived from the target monomer is preferably 60 mol% or more, more preferably 70 mol% or more, and even more preferably 80 to 100 mol%. For example, it is preferable that the aliphatic polyester resin is produced by polymerizing a raw material containing an aliphatic diol and an aliphatic dicarboxylic acid component at 50 mol% or more, preferably 60 mol% or more, more preferably 70 mol% or more, and even more preferably 80 to 100 mol% of the total monomer components used in the polymerization reaction of the aliphatic polyester resin.

[0022] The melt flow rate (MFR) of component (a), measured at 190°C and 2.16 kg, is preferably 0.1 g / 10 min or more, more preferably 0.5 g / 10 min or more, more preferably 1 g / 10 min or more, and is preferably 1,000 g / 10 min or less, more preferably 500 g / 10 min or less, more preferably 100 g / 10 min or less, even more preferably 50 g / 10 min or less, and particularly preferably 10 g / 10 min or less. By setting the MFR of component (a) within the above range, the characteristic of obtaining sufficient heat seal strength can be exhibited.

[0023] [Aliphatic polyester resin (a1) having aliphatic diol units and aliphatic dicarboxylic acid units as main structural units] The component (a1) is, for example, an aliphatic polyester resin having, as main constituent units, an aliphatic diol unit represented by the following formula (1) and an aliphatic dicarboxylic acid unit represented by the following formula (2).

[0024] -OR 11 -O-(1) [In formula (1), R 11 represents a divalent chain aliphatic hydrocarbon group which may have an oxygen atom in the chain, and when copolymerized, the number of types is not limited to one.

[0025] -OC-R 21 -CO-(2) [In formula (2), R 21 represents a direct bond or a divalent chain aliphatic hydrocarbon group, and when copolymerized, is not limited to one type.

[0026] The aliphatic diol that provides the diol unit of the formula (1) is not particularly limited, but for example, an aliphatic diol having 2 to 10 carbon atoms is preferable, and an aliphatic diol having 4 to 6 carbon atoms is more preferable. Specific examples include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, neopentyl glycol, diethylene glycol, polyethylene glycol, polypropylene glycol, and polytetramethylene ether glycol. Among them, 1,4-butanediol is preferable. The aliphatic diol may be used alone or in combination of two or more kinds.

[0027] The aliphatic dicarboxylic acid component that gives the aliphatic dicarboxylic acid unit of the formula (2) is an aliphatic dicarboxylic acid or an aliphatic dicarboxylic acid derivative such as an alkyl ester thereof, and the aliphatic dicarboxylic acid is not particularly limited, but is preferably an aliphatic dicarboxylic acid having 2 to 40 carbon atoms, more preferably an aliphatic dicarboxylic acid having 4 to 10 carbon atoms. Specific examples include succinic acid, adipic acid, suberic acid, sebacic acid, and dodecanedioic acid. Among them, succinic acid, adipic acid, and sebacic acid are preferred, succinic acid and adipic acid are more preferred, and succinic acid is particularly preferred. The aliphatic dicarboxylic acid component may be used alone or in combination of two or more kinds.

[0028] Specific examples of the component (a1) include aliphatic polyester resins containing 1,4-butanediol and succinic acid, aliphatic polyester resins containing 1,4-butanediol, adipic acid, and succinic acid, etc. More specifically, polybutylene succinate, polybutylene succinate adipate, etc. are preferred.

[0029] When the aliphatic dicarboxylic acid is succinic acid, the ratio of the succinic acid-derived constituent units in the total dicarboxylic acid units of the aliphatic polyester resin is usually 50 to 100 mol%, preferably 80 to 100 mol%, more preferably 90 to 100 mol%. By keeping it within this range, it is possible to exhibit the characteristic that sufficient heat sealability can be obtained.

[0030] When the aliphatic dicarboxylic acid is succinic acid and adipic acid, the ratio of the succinic acid-derived constituent units in the total dicarboxylic acid units of the aliphatic polyester resin is usually 50 to 95 mol%, preferably 60 to 93 mol%, more preferably 70 to 90 mol%, and the ratio of the adipic acid-derived constituent units in the total dicarboxylic acid units is usually 5 to 50 mol%, preferably 7 to 40 mol%, more preferably 10 to 30 mol%. By keeping it within this range, it is possible to exhibit the characteristic that sufficient heat sealability can be obtained.

[0031] The component (a1) preferably has the following physical properties: The weight average molecular weight (Mw) of the (a1) component is preferably 10,000 or more, more preferably 20,000 or more, and even more preferably 50,000 or more, and is preferably 1,000,000 or less, more preferably 500,000 or less, and even more preferably 400,000 or less. By keeping it within this range, the characteristic of being able to obtain sufficient heat sealability can be exhibited. The weight average molecular weight (Mw) is a value measured by gel permeation chromatography (GPC) using polystyrene as a standard substance.

[0032] The melt flow rate (MFR) of the (a1) component, measured at 190°C and 2.16 kg, is preferably 0.1 g / 10 min or more, more preferably 0.5 g / 10 min or more, more preferably 1 g / 10 min or more, and is preferably 1,000 g / 10 min or less, more preferably 500 g / 10 min or less, more preferably 100 g / 10 min or less, even more preferably 50 g / 10 min or less, and particularly preferably 10 g / 10 min or less. By keeping it within this range, the characteristic of being able to obtain sufficient heat sealability can be exhibited.

[0033] The melting point of the (a1) component is preferably 70° C. or higher, more preferably 75° C. or higher, and is preferably 250° C. or lower, more preferably 200° C. or lower, and particularly preferably 150° C. or lower. When there are multiple melting points, it is preferable that at least one of the melting points is within the above range. By keeping the melting point within this range, it is possible to exhibit the characteristic of obtaining sufficient heat sealability (transparency of the coating film, heat seal strength at low temperatures).

[0034] The physical properties of the aliphatic polyester resin (a) used in the present invention are the same as those described in the section [Aliphatic polyester resin (a1) having aliphatic diol units and aliphatic dicarboxylic acid units as main structural units] unless otherwise specified.

[0035] [Aliphatic polyester resin (a2) having aliphatic oxycarboxylic acid units as main structural units] Specific examples of the aliphatic oxycarboxylic acid component that provides the aliphatic oxycarboxylic acid unit of the component (a2) include, for example, lactic acid, glycolic acid, 2-hydroxy-n-butyric acid, 3-hydroxybutyric acid, 4-hydroxybutyric acid, 2-hydroxycaproic acid, 6-hydroxycaproic acid, 2-hydroxy-3,3-dimethylbutyric acid, 2-hydroxy-3-methylbutyric acid, 2-hydroxyisocaproic acid, 3-hydroxyvaleric acid, malic acid, citric acid, and the like, or lower alkyl esters or intramolecular esters thereof. In addition, lactone compounds such as ε-caprolactone are also included in the aliphatic oxycarboxylic acid in the present invention. When optical isomers exist in these, they may be any of D-form, L-form, or racemic form, and may be in the form of a solid, liquid, or aqueous solution. Among these, lactic acid, glycolic acid, 3-hydroxybutyric acid, 4-hydroxybutyric acid, 6-hydroxycaproic acid, and 3-hydroxyvaleric acid are preferred. These aliphatic oxycarboxylic acids may be used alone or in combination of two or more.

[0036] Specific examples of the component (a2) include polylactic acid, polyglycolic acid, poly 3-hydroxybutyrate, poly 4-hydroxybutyrate, poly(3-hydroxybutyrate-co-3-hydroxyvalerate), polycaprolactone, and the like.

[0037] The composition of lactic acid contained in polylactic acid is preferably D-lactic acid:L-lactic acid=100:0-85:15 or 0:100-15:85 in molar ratio. It is also possible to blend other polylactic acid having different composition ratios of D-lactic acid and L-lactic acid. Polylactic acid having only D-lactic acid or only L-lactic acid as a constituent unit becomes a crystalline resin, and tends to have a high melting point and excellent heat resistance and mechanical properties.

[0038] Furthermore, the polylactic acid may be a copolymer of the above-mentioned polylactic acid and other oxycarboxylic acids, or may contain a small amount of units derived from a chain extender. Examples of other oxycarboxylic acids include optical isomers of lactic acid (D-lactic acid for L-lactic acid, L-lactic acid for D-lactic acid), glycolic acid, 3-hydroxybutyric acid, 4-hydroxybutyric acid, 2-hydroxy-n-butyric acid, 2-hydroxy-3,3-dimethylbutyric acid, 2-hydroxy-3-methylbutyric acid, 2-methyllactic acid, and bifunctional aliphatic oxycarboxylic acids such as 2-hydroxycaproic acid, and lactones such as caprolactone, butyrolactone, and valerolactone. It is preferable to use units derived from such other oxycarboxylic acids in less than 15 mol% of the total structural units of the polylactic acid from the viewpoint of heat seal strength.

[0039] The weight average molecular weight (Mw) of the (a2) component is preferably 60,000 or more, more preferably 80,000 or more, and particularly preferably 100,000 or more, and is preferably 700,000 or less, more preferably 400,000 or less, and particularly preferably 300,000 or less. By keeping it within this range, the characteristic of obtaining sufficient heat seal strength can be exhibited. The weight average molecular weight (Mw) is a value measured by gel permeation chromatography (GPC) using polystyrene as a standard substance.

[0040] The melt flow rate (MFR) of the (a2) component, measured at 190° C. and 2.16 kg, is preferably 0.1 g / 10 min or more, more preferably 0.5 g / 10 min or more, more preferably 1 g / 10 min or more, and is preferably 1,000 g / 10 min or less, more preferably 500 g / 10 min or less, more preferably 100 g / 10 min or less, even more preferably 50 g / 10 min or less, and particularly preferably 10 g / 10 min or less. By keeping it within this range, the characteristic of obtaining sufficient heat seal strength can be exhibited.

[0041] [Aliphatic-aromatic polyester resin (a3) ​​having, as main constituent units, an aliphatic diol unit, an aliphatic dicarboxylic acid unit, and an aromatic dicarboxylic acid unit] The (a3) ​​component essentially comprises, for example, an aliphatic diol unit represented by the formula (1), an aliphatic dicarboxylic acid unit represented by the formula (2), and an aromatic dicarboxylic acid unit represented by the following formula (3). It may further contain the above-mentioned oxycarboxylic acid unit.

[0042] -OC-R 31 -CO-(3) [In formula (3), R 31 represents a divalent aromatic hydrocarbon group, and when copolymerized, the number of types is not limited to one.

[0043] The aliphatic diol that provides the diol unit of the formula (1) and the aliphatic dicarboxylic acid component that provides the aliphatic dicarboxylic acid unit of the formula (2) are the same as those exemplified in the above description of [Aliphatic polyester resin (a1) having aliphatic diol units and aliphatic dicarboxylic acid units as main constituent units], and the preferred ones are also the same.

[0044] The aromatic dicarboxylic acid component that gives the aromatic dicarboxylic acid unit of formula (3) is not particularly limited, but examples thereof include terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, diphenyldicarboxylic acid, etc. These may be acid anhydrides. In addition, examples of the derivatives of aromatic dicarboxylic acids include lower alkyl esters of these aromatic dicarboxylic acids. Among these, terephthalic acid, isophthalic acid, or lower alkyl (e.g., alkyl having 1 to 4 carbon atoms) ester derivatives thereof are preferred. These may be used alone or in combination of two or more. In particular, terephthalic acid and / or methyl ester of terephthalic acid, or a mixture containing terephthalic acid and / or methyl ester of terephthalic acid and isophthalic acid and / or methyl ester of isophthalic acid are preferred.

[0045] As a specific example of the aliphatic aromatic polyester resin, polybutylene alkylate terephthalate is preferable, polybutylene adipate terephthalate or polybutylene succinate terephthalate is more preferable, and polybutylene adipate terephthalate is particularly preferable.

[0046] The melt flow rate (MFR) of the (a3) ​​component, measured at 190°C and 2.16 kg, is preferably 0.1 g / 10 min or more, more preferably 0.5 g / 10 min or more, more preferably 1 g / 10 min or more, and is preferably 1,000 g / 10 min or less, more preferably 500 g / 10 min or less, more preferably 100 g / 10 min or less, even more preferably 50 g / 10 min or less, and particularly preferably 10 g / 10 min or less. By keeping it within this range, the characteristic of obtaining sufficient heat seal strength can be exhibited.

[0047] In the present invention, the aliphatic polyester resin (a) may be used alone or in combination of two or more kinds. For example, two or more kinds of aliphatic polyester resins having different diol units or dicarboxylic acid units may be mixed and used.

[0048] The content of the (A) component is not particularly limited, but is preferably 15% by mass or more, more preferably 20% by mass or more, and even more preferably 30% by mass or more, based on the total amount of the aqueous resin dispersion. Also, it is preferably 75% by mass or less, more preferably 65% ​​by mass or less, and even more preferably 60% by mass or less. When the content is equal to or more than the lower limit, the heat seal strength is excellent, and when the content is equal to or less than the upper limit, the storage stability of the aqueous resin dispersion is excellent.

[0049] [Nonionic dispersant (B)] As the nonionic dispersant (B), a commonly used known nonionic dispersant can be used. For example, a nonionic water-soluble polymer, a nonionic surfactant, etc. can be mentioned. These may be used alone or in combination of two or more kinds.

[0050] Examples of the nonionic water-soluble polymer include, but are not limited to, polyvinyl alcohol resins (hereinafter, sometimes referred to as "PVA resins"), cellulose derivatives such as methyl cellulose, ethyl cellulose, hydroxymethyl cellulose, hydroxypropyl methyl cellulose, hydroxybutyl methyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, aminomethyl hydroxypropyl cellulose, and aminoethyl hydroxypropyl cellulose, starch, tragacanth, pectin, glue, alginic acid or a salt thereof, gelatin, polyvinylpyrrolidone, polyacrylic acid or a salt thereof, polymethacrylic acid or a salt thereof, polyacrylamide, polymethacrylamide, copolymers of vinyl acetate and unsaturated acids such as maleic acid, maleic anhydride, acrylic acid, methacrylic acid, itaconic acid, fumaric acid, and crotonic acid, copolymers of styrene and the above unsaturated acids, copolymers of vinyl ether and the above unsaturated acids, and salts of the above copolymers.

[0051] Examples of the nonionic surfactant include nonionic surfactants, which are not limited to the following, and include polyoxyethylene alkylamino ethers such as polyoxyethylene nonylphenyl ether, polyoxyethylene octylnonyl ether, polyoxyethylene dodecylphenyl ether, polyoxyethylene alkyl allyl ether, polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monopalmitate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan monooleate, polyoxyethylene lauryl amino ether, and polyoxyethylene stearyl amino ether. Among these, the PVA-based resin is preferably used from the viewpoint of enhancing the stability of the aqueous resin dispersion.

[0052] [Polyvinyl alcohol resin] The polyvinyl alcohol-based resin (PVA-based resin) used in the present invention includes unmodified polyvinyl alcohol resin (hereinafter, sometimes referred to as "unmodified PVA resin") and modified polyvinyl alcohol resin (hereinafter, sometimes referred to as "modified PVA resin").

[0053] The unmodified PVA resin can be produced by saponifying a vinyl ester polymer obtained by polymerizing a vinyl ester compound to within the range of the average degree of saponification described below. Examples of such vinyl ester compounds include vinyl formate, vinyl acetate, vinyl trifluoroacetate, vinyl propionate, vinyl butyrate, vinyl caprate, vinyl laurate, vinyl versatate, vinyl palmitate, vinyl stearate, etc., with vinyl acetate being preferred. The vinyl ester compounds may be used alone or in combination of two or more.

[0054] The modified PVA resin can be produced by copolymerizing the vinyl ester compound with an unsaturated monomer copolymerizable with the vinyl ester compound, followed by saponification. Examples of the unsaturated monomer copolymerizable with the vinyl ester compound include olefins such as ethylene, propylene, isobutylene, α-octene, α-dodecene, α-octadecene, etc., hydroxyl group-containing α-olefins such as 3-buten-1-ol, 4-penten-1-ol, 5-hexen-1-ol, etc., and derivatives such as acylated products thereof; unsaturated acids such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, maleic anhydride, itaconic acid, undecylenic acid, etc., salts thereof, monoesters, or dialkyl esters thereof; amides such as diacetone acrylamide, acrylamide, methacrylamide, etc.; olefin sulfonic acids such as ethylene sulfonic acid, allyl sulfonic acid, methallyl sulfonic acid, etc., or salts thereof. These can be used alone or in combination of two or more kinds.

[0055] In addition, the modified PVA resin may be a PVA resin having a primary hydroxyl group in the side chain. The number of primary hydroxyl groups in the side chain is usually 1 to 5, preferably 1 to 2, and particularly preferably 1. Furthermore, the modified PVA resin is preferably a PVA resin having a primary hydroxyl group and a secondary hydroxyl group. Examples of such modified PVA resins include a PVA resin having a hydroxyalkyl group in the side chain, a PVA resin having a 1,2-diol structural unit in the side chain, and the like.

[0056] The average saponification degree of the PVA resin is preferably 70 mol% to 100 mol%, more preferably 75 to 99 mol%, further more preferably 75 to 95 mol%, and particularly preferably 75 to 90 mol%. If the average saponification degree is too low, the water resistance of the film obtained by using the aqueous resin dispersion tends to decrease.

[0057] In particular, when an unmodified PVA resin is used as the PVA resin, the average saponification degree is preferably 70 mol% to 100 mol%, more preferably 75 mol% to 95 mol%, and even more preferably 75 mol% to 90 mol%. If the average saponification degree is too low, the water resistance of the film obtained by using the aqueous resin dispersion tends to decrease.

[0058] When a modified PVA resin is used as the PVA resin, the average saponification degree is preferably 70 mol% to 100 mol%, more preferably 75 to 99 mol%, and even more preferably 75 to 95 mol%. If the average saponification degree is too low, the water resistance of the film obtained by using the aqueous resin dispersion tends to decrease. The average degree of saponification is measured in accordance with JIS K 6726 3.5.

[0059] The viscosity of a 4% by mass aqueous solution of the PVA resin at 20°C (hereinafter sometimes simply referred to as "viscosity") is preferably 2 to 70 mPa s, more preferably 5 to 60 mPa s, and even more preferably 20 to 55 mPa s. If the viscosity is too low, the stability of the aqueous resin dispersion tends to decrease.

[0060] When an unmodified PVA resin is used as the PVA resin, the viscosity of a 4 mass% aqueous solution of the unmodified PVA resin at 20° C. is preferably 2 to 70 mPa s, more preferably 5 to 60 mPa s, and even more preferably 20 to 55 mPa s. If the viscosity is too low, the stability of the aqueous resin dispersion tends to decrease.

[0061] Furthermore, when a modified PVA resin is used as the PVA resin, the viscosity of a 4 mass% aqueous solution of the modified PVA resin at 20° C. is preferably 5 to 50 mPa s, more preferably 10 to 40 mPa s, and even more preferably 15 to 30 mPa s. If the viscosity is too low, the stability of the aqueous resin dispersion tends to decrease. The viscosity of the 4% by mass aqueous solution (viscosity) is measured in accordance with JIS K 6726 3.11.2.

[0062] The average degree of polymerization of the PVA-based resin is preferably 50 to 5,000, more preferably 150 to 4,000, even more preferably 300 to 3,000, and particularly preferably 1,000 to 3,000. By keeping it within this range, the characteristic of sufficient durability against water can be exhibited. The average degree of polymerization can be determined according to the method for calculating the average degree of polymerization described in JIS K 6726.

[0063] In the present invention, the PVA-based resins may be used alone, or unmodified PVA-based resins may be used in combination, or modified PVA-based resins may be used in combination, or an unmodified PVA resin may be used in combination with a modified PVA-based resin. Furthermore, two or more types of PVA-based resins differing in average saponification degree, viscosity, type of modification, amount of modification, etc. may be used in combination.

[0064] The content of the nonionic dispersant (B) is 3 parts by mass or more and less than 10 parts by mass relative to 100 parts by mass of the dispersoid (A). It is preferably 4 parts by mass or more, and more preferably 5 parts by mass or more. The upper limit is preferably 9 parts by mass or less, and more preferably 7 parts by mass or less. When the content is within the above range, the effects of the present invention can be obtained.

[0065] The content of the nonionic dispersant (B) component is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, even more preferably 1% by mass or more, and particularly preferably 2% by mass or more, based on the total amount of the aqueous resin dispersion. Also, it is preferably 20% by mass or less, more preferably 15% by mass or less, even more preferably 12% by mass or less, and particularly preferably 10% by mass or less. If it is lower than this range, the stability of the aqueous resin dispersion tends to decrease. If it is higher than this range, the water resistance of the film obtained using the aqueous resin dispersion tends to decrease.

[0066] [Dispersion medium (C)] The dispersion medium (C) is not particularly limited as long as it is a water-soluble component in the substance and concentration range that does not affect the stability of the aqueous resin dispersion, and any aqueous solution containing the component may be used, including water alone, an aqueous polysaccharide solution, an aqueous cellulose solution, etc., and may be used in combination with a small amount of a water-soluble organic solvent. Examples of the organic solvent include methanol, ethanol, acetone, isopropyl alcohol, etc. Among these, water is the most preferable as the dispersion medium.

[0067] The content of the (C) component is not particularly limited, but is preferably 25% by mass or more, more preferably 35% by mass or more, and even more preferably 40% by mass or more, based on the total amount of the aqueous resin dispersion. Also, it is preferably 84% by mass or less, more preferably 80% by mass or less, and even more preferably 70% by mass or less. When the content is equal to or more than the lower limit, the storage stability of the aqueous resin dispersion is excellent, and when the content is equal to or less than the upper limit, the heat seal strength is excellent.

[0068] When the dispersion medium is a combination of water and an organic solvent, the content of water in the total amount of the dispersion medium is preferably 60% by mass or more, more preferably 70% by mass or more, and even more preferably 90% by mass or more. Among these, it is most preferable to use only water as the dispersion medium.

[0069] [Other ingredients] In addition to the above-mentioned components, the aqueous resin dispersion according to one embodiment of the present invention may contain other components that are commonly used in aqueous resin dispersions within a range that does not impair the effects of the present invention (for example, 10% by mass or less). Such components are not particularly limited, but examples thereof include plasticizers, preservatives, antifungal agents, antibacterial agents, thermoplastic resins, various stabilizers, ultraviolet absorbers, light stabilizers, antioxidants, antistatic agents, rust inhibitors, hardeners, fillers, thickeners, etc. In addition, as the dispersion medium, a dispersion medium containing a solute such as a polysaccharide aqueous solution or a cellulose aqueous solution is mentioned, but when a dispersion medium containing a solute is used as the dispersion medium, the solute is treated as another component.

[0070] [Method for producing aqueous resin dispersion] The method for producing the aqueous resin dispersion according to an embodiment of the present invention can employ known production methods in the field, such as a phase inversion emulsification method, a high-pressure emulsification method, and a solvent replacement method. For example, the transfer emulsification method is a method in which a dispersoid (A) is melt-kneaded, and a phase inversion emulsification step is performed in which a nonionic dispersant (B) and a dispersion medium (C) are added to the melt-kneaded composition and mixed. The high-pressure emulsification method is a method in which the dispersoid (A), the nonionic dispersant (B), and the dispersion medium (C) are charged, and then pressurized while being heated and stirred to disperse. The solvent replacement method is a method in which the dispersoid (A), the nonionic dispersant (B), and the dispersion medium (C) dissolved in an organic solvent are added, stirred, and dispersed, and then the organic solvent is removed.

[0071] Specifically, a dispersoid (A) is charged into a kneader, and optionally a solvent and the like are added, followed by melt-kneading under heating conditions, to which a nonionic dispersant (B) such as a PVA-based resin and a dispersion medium (C) such as water are added, and these components are mixed and phase-inverted to cause emulsification.

[0072] The heating temperature for the melt kneading is usually 40 to 250° C., preferably 60 to 200° C., more preferably 60 to 160° C., and even more preferably 80 to 150° C. The heating time is usually 10 to 1,800 seconds, preferably 10 to 600 seconds, and more preferably 20 to 180 seconds.

[0073] When producing using an extruder, for example, a dispersoid (A) containing an aliphatic polyester resin (a) is continuously fed from a hopper of the extruder or a separate supply port and melt-kneaded under heating conditions, a nonionic dispersant (B) such as a PVA resin and a dispersion medium (C) such as water are added from another supply port provided in the extruder, kneaded and dispersed to effect phase inversion emulsification, and then continuously extruded from a die to obtain an aqueous resin dispersion according to an embodiment of the present invention.

[0074] [Aqueous resin dispersion] The aqueous resin dispersion of the present embodiment obtained as described above is an aqueous resin dispersion. Such an aqueous resin dispersion is a dispersion of particulate matter dispersed in an aqueous solvent, specifically, a dispersion system in which the dispersion medium (i.e., continuous phase) is an aqueous liquid such as water and / or an organic solvent in which the dispersoid is substantially insoluble or has a significantly low solubility. In the aqueous resin dispersion of the present embodiment, the aliphatic polyester resin (a) is the dispersoid, and these are dispersed in an aqueous solvent.

[0075] The dispersed particle diameter of the dispersoid in the aqueous resin dispersion according to one embodiment of the present invention is preferably 10 μm or less, more preferably 5 μm or less, more preferably 3 μm or less, and even more preferably 2.5 μm or less. The lower limit is usually about 0.01 μm. By keeping the diameter within this range, the aqueous resin dispersion can exhibit the characteristic of excellent storage stability. The dispersed particle size is the median size (d50) corresponding to 50% of the cumulative particle size distribution value on a volume basis, and can be measured, for example, by a laser diffraction particle size measuring device (e.g., model number SALD-2200, manufactured by Shimadzu Corporation).

[0076] In order to further improve the biodegradability of the aqueous resin dispersion according to one embodiment of the present invention, it is preferable to use biodegradable components as the aliphatic polyester resin (a) and the nonionic dispersant (B), and it is particularly preferable to use a PVA resin as the nonionic dispersant (B).

[0077] [Application] The aqueous resin dispersion according to one embodiment of the present invention can be used in the form of a molded article (film, etc.) obtained by a known molding method using the aqueous resin dispersion, although this is not limited thereto. Furthermore, the aqueous resin dispersion according to one embodiment of the present invention can be used as, for example, an adhesive, a pressure sensitive adhesive, a modifier thereof, a coating agent, a heat sealant, a paint, a primer for paint, an ink, a binder, etc., in paper, a film, a sheet, a structural material, a building material, an automobile part, an electric / electronic product, a packaging material, clothing, a medicine, a cosmetic (shampoo, rinse, emulsion, lotion, perfume, etc.), an agricultural composition (agricultural chemical emulsion, etc.), a health food, a food, etc. Among them, a cosmetic, an agricultural composition, a paint, an ink, or an adhesive containing the aqueous resin dispersion according to one embodiment of the present invention is preferable. In addition, the aqueous resin dispersion according to one embodiment of the present invention is preferably used as a coating agent for a coated object (object to be coated) from the viewpoint of excellent heat sealability, film-forming property, etc. The heat sealability and film-forming property of the coating agent containing the aqueous resin dispersion can be evaluated, for example, by the method described in the examples below.

[0078] The object to be coated with the aqueous resin dispersion according to one embodiment of the present invention is not particularly limited, but is preferably, for example, a paper substrate or a plastic substrate. Examples of the paper base material include thermal recording paper, release paper, peeling paper, inkjet paper, carbon paper, non-carbon paper, base paper for paper cups, greaseproof paper, paperboard such as Manila board, white board, and liner, printing paper such as general fine paper, medium quality paper, and gravure paper, high-grade, medium-grade, and low-grade paper, newsprint, etc. For example, a laminate including a layer made of a paper base material and a layer made of an aqueous resin dispersion coated on the paper base material is also suitable.

[0079] Examples of the plastic substrate include polyethylene terephthalate (PET) resin, polypropylene (PP) resin (biaxially oriented polypropylene (OPP), non-axially oriented polypropylene (CPP)), nylon resin, various biodegradable resins, polyethylene (PE) resin (low density polyethylene (LDPE), high density polyethylene (HDPE)), etc. For example, a laminate including a layer made of a plastic substrate and a layer made of an aqueous resin dispersion coated on the plastic substrate is also suitable.

[0080] The coating method using the aqueous resin dispersion according to one embodiment of the present invention is not particularly limited, and examples thereof include a roll coating method, a dip coating method, a bar coating method, a nozzle coating method, a die coating method, a spray coating method, a spin coating method, a curtain coating method, and a flow coating method. EXAMPLES

[0081] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples as long as it does not depart from the gist of the invention. In the examples, "parts" and "%" are based on mass.

[0082] The following were prepared as dispersoid (A) and nonionic dispersant (B). <Component (A)> Dispersoid (A-1): Polybutylene succinate adipate (a1) [BiOPBS (FD92) manufactured by PTT MCC Biochem, melt flow rate (MFR) 4g / 10min (190℃, 2.16kg), melting point 86℃] Dispersoid (A'-1): Polybutylene succinate adipate (dispersoid A-1) and mixed dibasic acid ester (Daihachi Chemical Industry Co., Ltd. "DAIFATTY-101") were melt-kneaded at 140°C in a mass ratio of 80:20 using a twin-screw extruder (melt flow rate (MFR) of the resin: 30g / 10min (190°C, 2.16kg), melting point: 86°C). Dispersoid (A'-2): Polybutylene succinate adipate (dispersoid A-1) and mixed dibasic acid ester (Daihachi Chemical Industry Co., Ltd. "DAIFATTY-101") were melt-kneaded at 140°C in a mass ratio of 88:12 using a twin-screw extruder (melt flow rate (MFR) of the resin: 15g / 10min (190°C, 2.16kg), melting point: 86°C).

[0083] <(B) component> (b1) PVA resin [unmodified PVA resin, average degree of polymerization 2000, degree of saponification 78.5 to 81.5%, 4% viscosity at 20°C 44.0 to 52.0 mPa s] (b2) PVA resin [unmodified PVA resin, average degree of polymerization 1400, degree of saponification 86.5 to 89.0%, 4% viscosity at 20°C 20.5 to 24.5 mPa s] (b3) PVA resin [unmodified PVA resin, average degree of polymerization 500, degree of saponification 86.5 to 89.0%, 4% viscosity at 20°C 4.8 to 5.8 mPa s] (b4) PVA resin [unmodified PVA resin, average degree of polymerization 1700, degree of saponification 86.5 to 89.0%, 4% viscosity at 20°C 20.5 to 24.5 mPa s]

[0084] [Examples 1 and 2] Dispersoid A was continuously fed from the hopper of a twin-screw extruder [TEX30HSS, manufactured by Japan Steel Works, Ltd.] and melted under the condition of a heating temperature (cylinder temperature) of 120° C. to 220° C. Next, while continuously feeding PVA-based resin (b1) as a dispersant and water as a dispersion medium from a feed port provided in the extruder, it was continuously extruded (screw rotation speed: 300 rpm) under the condition of a heating temperature (cylinder temperature) of 90 to 105° C. to obtain an aqueous resin dispersion having the mass ratio shown in Table 1 below. The dispersed particle diameter (median diameter) in the aqueous resin dispersion was measured with a laser diffraction particle diameter measuring device (SALD-2200, manufactured by Shimadzu Corporation) and was found to be 2.3 μm.

[0085] [Comparative Examples 1 to 5] Instead of Example 1, an aqueous resin dispersion having the composition shown in Table 1 was prepared.

[0086] The following evaluations were carried out for the aqueous dispersions of Example 1 and Comparative Examples 1 to 4. The heat sealability and Cobb water absorbency of the coating layer were evaluated. The results are shown in Table 1 below.

[0087] [Heat sealability test] The obtained aqueous resin dispersion was mixed with water at a basis weight of 50 g / m 27g / m2 printed on one side of glossy bleached kraft paper with a barcode reader 2 The resulting coated paper was cut into strips 15 cm long and 15 mm wide, and the coated surfaces were placed together and dried at 150°C and 1.3 kg / cm 2 A test piece (coated paper) was obtained by heat sealing under conditions of a pressure of 1000 g for 1 second. Using this test piece, a 180° peel test was performed at a tensile speed of 200 mm / min using a tensile tester (PT-200N, manufactured by MinebeaMitsumi Inc.), and the test piece was evaluated according to the following criteria. (Evaluation Criteria) ○ 3.8N / 15mm or more △ 2.8N / 15mm or more, less than 3.8N / 15mm ×...Less than 2.8N / 15mm

[0088] [Water resistance (humidity)] The obtained aqueous resin dispersion was mixed with water at a basis weight of 50 g / m 2 The coating was applied to a single-sided gloss bleached kraft paper using a bar coder and dried at 100°C for 20 seconds. The resulting coated paper was cut into a 13cm x 13cm square to obtain a test piece (coated paper). The test piece was placed with the coated side facing up in a Gurley-type Cobb sizing tester (PU-1004, manufactured by Tester Sangyo Co., Ltd.) and 100ml of water was poured into the cylinder. After 120 seconds, the water in the cylinder was discarded and the test piece was quickly removed. A dried blotting paper was placed on the test piece and a 10kg metal roller was rolled twice (one round trip) without applying pressure to remove excess water. The wet side of the test piece was immediately folded inward and the mass was measured. The water absorbency was calculated using the following formula. A=(m2-m1) / F A: Water absorption (g / m 2 ) m1: dry mass of the test piece (before the test), m2: wet mass of the test piece (after the test) F: 10000 / S, S: test area (cm 2 ) (Evaluation Criteria) 〇 20g / m 2 less than △ 25g / m 2 Less than 20g / m 2 End × 25g / m 2 End

[0089] [Table 1]

[0090] As shown in Table 1, Examples 1 and 2 using the aqueous resin dispersion of the present invention were excellent in heat sealability and durability. On the other hand, Comparative Examples 1 and 3 in which the MFR of the dispersoid (A) was too high were poor in heat sealability and durability. Comparative Example 2 in which the MFR of the dispersoid (A) was higher than the range and the amount of nonionic dispersant (B) used was too high was poor in heat sealability and durability. Furthermore, Comparative Example 4 in which the MFR of the dispersoid (A) was higher than the range was good in heat sealability but poor in durability. Furthermore, Comparative Example 5 in which the amount of nonionic dispersant (B) used was greater than the range was poor in durability. [Industrial Applicability]

[0091] The aqueous resin dispersion and emulsion compositions of the present invention are particularly useful as various coating agents, for example, as coating agents for paper substrates, coating agents for plastic substrates, and the like.

Claims

1. An aqueous resin dispersion (I) comprising a dispersoid (A) containing an aliphatic polyester resin (a), a nonionic dispersant (B), and a dispersion medium (C), The dispersoid (A) has a melt flow rate (MFR) of less than 15 g / 10 min at 190° C. under a load of 2.16 kg; The content of the nonionic dispersant (B) is 0.1 parts by mass or more and less than 10 parts by mass per 100 parts by mass of the dispersoid (A).

2. 2. The aqueous resin dispersion according to claim 1, wherein the aliphatic polyester resin (a) has a melt flow rate (MFR) of 100 g / 10 min or less at 190° C. under a load of 2.16 kg.

3. 2. The aqueous resin dispersion according to claim 1, wherein the aliphatic polyester resin (a) is polybutylene succinate and / or polybutylene succinate adipate.

4. 2. The aqueous resin dispersion according to claim 1, wherein the nonionic dispersant (B) is a polyvinyl alcohol-based resin.

5. 3. The aqueous resin dispersion according to claim 1, wherein the nonionic dispersant (B) is an unmodified polyvinyl alcohol resin.

6. 5. The aqueous resin dispersion according to claim 4, wherein the polyvinyl alcohol resin has a degree of saponification of 70 to 90 mol %.

7. 5. The aqueous resin dispersion according to claim 4, wherein the polyvinyl alcohol-based resin has an average degree of polymerization of 1,000 to 3,000.

8. The aqueous resin dispersion according to claim 4, wherein the polyvinyl alcohol-based resin has a 4 mass% aqueous solution viscosity at 20° C. of 2 to 70 mPa·s.

9. 2. The aqueous resin dispersion according to claim 1, wherein the dispersion medium (C) is water.

10. A coating agent comprising the aqueous resin dispersion according to claim 1.

11. The coating agent according to claim 10, wherein the substrate to be coated is a paper substrate.

12. The coating agent according to claim 10, wherein the object to be coated is a plastic substrate.

13. A molded article obtained by using the aqueous resin dispersion according to claim 1 or 2.

14. A film obtained by using the aqueous resin dispersion according to claim 1 or 2.

15. A cosmetic comprising the aqueous resin dispersion according to claim 1 or 2.

16. 3. An agricultural composition comprising the aqueous resin dispersion according to claim 1 or 2.

17. A paint comprising the aqueous resin dispersion according to claim 1 or 2.

18. An ink comprising the aqueous resin dispersion according to claim 1 or 2.

19. A pressure-sensitive adhesive comprising the aqueous resin dispersion according to claim 1 or 2.

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