Powder composition, agricultural composition using the same, re-emulsifiable aqueous resin dispersion, coating agent using the same, and method for producing powder composition

Abstract

To provide a dry resin powder which is a powder composition using a resin powder obtained by drying an aqueous resin dispersion containing an aliphatic polyester-based resin, is excellent in sustained releasability, and is excellent in heat sealability when the obtained powder composition is re-emulsified, coated, and dried.SOLUTION: The powder composition contains a polyester-based resin (A), wherein the polyester-based resin (A) is an aliphatic polyester-based resin, and the powder composition contains 0 pts. mass or more and less than 12 pts. mass of a plasticizer (B) and 2 pts. mass or more and less than 23 pts. mass of an inorganic filler (C) based on 100 pts. mass of the polyester-based resin (A).SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a powder composition containing a dried resin powder obtained by drying an aqueous dispersion, and further relates to an agricultural composition using the same, a re-emulsified aqueous resin dispersion, a coating agent using the same, and a method for producing the powder composition. [Background technology]

[0002] BACKGROUND ART Dried resin powders obtained by drying dispersions of various resin compositions in a dispersion medium such as water have conventionally been used for various applications. When the resin is in a dispersed state such as an aqueous dispersion, problems with storage stability arise, such as settling of dispersed particles, increase in viscosity, freezing, and spoilage. However, when the resin is made into a dry resin powder, these problems are less likely to occur. In view of these advantages, it is used as a coating agent and in agricultural compositions.

[0003] As the agricultural composition, a known example is a granular pesticide composition (granules) which is obtained by adding a small amount of water to a mixture of a pesticide active ingredient and a binder or a bulking agent, kneading the mixture, and then passing it through a granulator to produce fine particles. Known examples of such compositions include those in which the inner core is granulated and then granulated again (Patent Document 1), those in which the pesticide active ingredient and the resin coating are prepared separately (Patent Document 2), and those in which the composition is made of wax and a carrier (Patent Document 3).

[0004] However, in many cases, in order to control the release of the pesticide active ingredient and to enhance the durability of its efficacy, it has been necessary to prepare pesticide formulations through complicated processes. Therefore, there has been a demand for the development of a new granular pesticide composition that can be produced more efficiently and simply and has a long-lasting efficacy.

[0005] Patent Document 4 describes a sustained-release pesticide granule characterized by a uniform mixture of a pesticide active ingredient, a thermoplastic resin (A), polyvinyl alcohol (B), and iron or copper powder (C). In this pesticide granule, the presence of water molecules accelerates the oxidation of the contained iron or copper powder (C), increasing its volume and destroying the coating substance (thermoplastic resin (A)), which allows the pesticide active ingredient coated by the coating substance to gradually elute, thereby achieving a sustained-release effect. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Special Publication No. 64-4484 [Patent Document 2] Japanese Patent Application Laid-Open No. 2000-86404 [Patent Document 3] Japanese Patent Application Laid-Open No. 2004-43370 [Patent Document 4] Japanese Patent Application Laid-Open No. 2002-363003 Summary of the Invention [Problem to be solved by the invention]

[0007] However, among aqueous dispersions of thermoplastic resins, aqueous dispersions of polyester resins tend to hydrolyze over time, resulting in a decrease in storage stability. In addition, due to the recent increase in environmental concerns, efforts are being made to use biodegradable materials for all of these purposes. When used as a coating agent, heat sealing properties are required to seal the coating layer. The present invention has been made in consideration of the above-mentioned problems, and aims to provide a powder composition using a resin powder obtained by drying an aqueous resin dispersion containing an aliphatic polyester-based resin, and a dried resin powder that has excellent heat-sealing properties and sustained-release properties. [Means for solving the problem]

[0008] In view of the above circumstances, the present inventors have conducted extensive research and have found that a composition containing a dried resin powder obtained by drying a specific aqueous resin dispersion containing a polyester-based resin and an inorganic filler, i.e., a composition containing a polyester-based resin, an inorganic filler, and preferably a nonionic dispersant and a plasticizer, has excellent storage stability and sustained-release properties, and can also achieve heat-sealability when the obtained powder composition is re-emulsified, coated, and dried, thereby completing the present invention.

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

[11] . [1] A powder composition containing a polyester-based resin (A), wherein the polyester-based resin (A) is an aliphatic polyester-based resin, and the powder composition contains, per 100 parts by mass of the polyester-based resin (A), 0 parts by mass or more and less than 12 parts by mass of a plasticizer (B), and 2 parts by mass or more and less than 23 parts by mass of an inorganic filler (C). [2] The powder composition according to [1], wherein the polyester resin (A) contains 50 mol % or more of a structure derived from an aliphatic polyol and / or an aliphatic dicarboxylic acid. [3] The powder composition according to [1], wherein the polyester resin (A) is polybutylene succinate and / or polybutylene succinate adipate. [4] The powder composition according to [1], which contains a nonionic dispersant (D).

[0010] [5] The powder composition according to [4], wherein the nonionic dispersant (D) is a polyvinyl alcohol-based resin. [6] The powder composition according to [5], wherein the polyvinyl alcohol resin has an average degree of polymerization of 50 to 5,000. [7] The powder composition according to [4], wherein the content of the nonionic dispersant (D) is 0.1 parts by mass or more and 50 parts by mass or less per 100 parts by mass of the total amount of the polyester resin (A) and the plasticizer (B). [8] An agricultural composition containing the powder composition described in [1]. [9] A re-emulsified aqueous resin dispersion comprising the resin powder according to [1] and an aqueous medium.

[10] A coating agent containing the aqueous resin dispersion according to [9].

[0011]

[11] A method for producing a powder composition containing a dried resin powder (I) obtained by drying an aqueous resin dispersion (i) containing a polyester resin (A), wherein the polyester resin (A) is an aliphatic polyester resin, and the powder composition contains 0 to less than 12 parts by mass of a plasticizer (B) per 100 parts by mass of the polyester resin (A), 0.1 to 30 parts by mass of a nonionic dispersant (D) per 100 parts by mass of the total amount of the polyester resin (A) and the plasticizer (B), and 2 to less than 23 parts by mass of an inorganic filler (C) per 100 parts by mass of the dried resin powder (I).

[12] The method for producing a powder composition according to

[11] , wherein the dispersion medium of the aqueous resin dispersion (i) is water.

[13] The method for producing a powder composition according to

[11] , wherein the particle size of the dry resin powder (I) dispersed in water is less than 800% of the particle size of the aqueous resin dispersion (i).

[14] A method for producing the powder composition according to

[11] , characterized in that the aqueous resin dispersion (i) is spray-dried. [Effects of the Invention]

[0012] According to the present invention, a powder composition of dried resin powder obtained by drying an aqueous resin dispersion containing a polyester-based resin has excellent storage stability and sustained release properties, and can also achieve heat sealability when the dried resin powder is re-emulsified, coated, and dried. DETAILED DESCRIPTION OF THE INVENTION

[0013] The present invention will be described in more detail below based on embodiments of the present invention, but the present invention is not limited to these embodiments. In this specification, when an expression "X to Y" (X and Y are arbitrary numbers) is used, it means "at least X and at most Y" unless otherwise specified. Furthermore, "X and / or Y (X and Y are optional)" means at least one of X and Y, and means three possibilities: X only, Y only, and X and Y.

[0014] The powder composition of the present invention is a composition containing a dried resin powder (I) obtained by drying an aqueous resin dispersion (i) that contains a polyester resin (A), a plasticizer (B), and an inorganic filler (C), and more preferably a nonionic dispersant (D).

[0015] [Polyester resin (A)] The polyester resin (A) used in the present invention is composed of an aliphatic polyester resin (a), and this aliphatic polyester resin usually contains 50 mol % or more of a structure derived from an aliphatic polyol and / or an aliphatic dicarboxylic acid (hereinafter referred to as an "aliphatic structure." Note that this "aliphatic structure" includes an alicyclic structure). The structure constituting this polyester resin (A) may be a polyester resin having an entirely aliphatic structure, or an aliphatic-aromatic polyester resin having a partial aromatic structure in addition to the aliphatic structure.

[0016] Specific examples of the polyester resin (A) component include an aliphatic polyester resin (a1) (hereinafter sometimes referred to as "component (a1)") having aliphatic diol units and aliphatic dicarboxylic acid units as main structural units; an aliphatic polyester resin (a2) (hereinafter sometimes referred to as "component (a2)") having aliphatic oxycarboxylic acid units as main structural units; an aliphatic-aromatic polyester resin (a3) ​​(hereinafter sometimes referred to as "component (a3)") having aliphatic diol units, aliphatic dicarboxylic acid units, and aromatic dicarboxylic acid units as main structural units; and mixtures thereof. Among these, an aliphatic polyester resin (a1) having aliphatic diol units and aliphatic dicarboxylic acid units as main structural units is preferred.

[0017] Here, the term "unit" refers to a structural unit contained in the aliphatic polyester resin that is 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 accounts for 50 mol% or more of the total structural units of the aliphatic polyester resin. 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, the aliphatic polyester resin is preferably produced by polymerizing raw materials that contain an aliphatic diol and an aliphatic dicarboxylic acid component in an amount of 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.

[0018] The melt flow rate (MFR) of the polyester resin (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, 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 the MFR of component (a) within the above range, the characteristic of obtaining sufficient heat seal strength can be exhibited.

[0019] [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).

[0020] -OR 11 -O-(1) [In formula (1), R11 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.]

[0021] -OC-R 21 -CO-(2) [In formula (2), R21 represents a direct bond or a divalent chain aliphatic hydrocarbon group, and when copolymerized, is not limited to one type.]

[0022] The aliphatic diol that provides the diol unit of formula (1) is not particularly limited, but is preferably an aliphatic diol having 2 to 10 carbon atoms, and more preferably an aliphatic diol having 4 to 6 carbon atoms. 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. Of these, 1,4-butanediol is preferred. The aliphatic diols may be used alone or in combination of two or more.

[0023] The aliphatic dicarboxylic acid component that provides the aliphatic dicarboxylic acid unit of formula (2) is an aliphatic dicarboxylic acid or an aliphatic dicarboxylic acid derivative such as an alkyl ester thereof. 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. Of these, 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 components may be used alone or in combination of two or more.

[0024] Specific examples of the component (a1) include aliphatic polyester resins containing 1,4-butanediol and succinic acid, and aliphatic polyester resins containing 1,4-butanediol, adipic acid, and succinic acid. More specifically, polybutylene succinate, polybutylene succinate adipate, etc. are preferred.

[0025] When the aliphatic dicarboxylic acid is succinic acid, the proportion of the succinic acid-derived constituent units in all 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, the characteristic of being able to obtain sufficient heat-sealability can be exhibited.

[0026] When the aliphatic dicarboxylic acids are succinic acid and adipic acid, the proportion of the succinic acid-derived constituent units in all 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 proportion of the adipic acid-derived constituent units in all dicarboxylic acid units is usually 5 to 50 mol%, preferably 7 to 40 mol%, more preferably 10 to 30 mol%. By keeping the proportions within these ranges, the characteristic of obtaining sufficient heat-sealability can be exhibited.

[0027] The component (a1) preferably has the following physical properties: The weight average molecular weight (Mw) of component (a1) 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 obtaining 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.

[0028] The melt flow rate (MFR) of component (a1), measured at 190°C and 2.16 kg, is preferably 0.1 g / 10 min or 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, 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 the MFR within this range, the characteristic of obtaining sufficient heat-sealability can be exhibited.

[0029] The melting point of component (a1) is preferably 70°C or higher, more preferably 75°C or higher, and 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 melting point is within the above range. By ensuring that the melting point is within this range, the characteristic of obtaining sufficient heat sealability (transparency of the coating film, heat seal strength at low temperatures) can be exhibited.

[0030] 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.

[0031] [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 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, as well as lower alkyl esters or intramolecular esters thereof. Furthermore, lactone compounds such as ε-caprolactone are also encompassed by the aliphatic oxycarboxylic acid of the present invention. When optical isomers exist, they may be in the 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.

[0032] Specific examples of the component (a2) include polylactic acid, polyglycolic acid, polyhydroxyalkanoate, and polycaprolactone.

[0033] Examples of the structural units constituting the polyhydroxyalkanoate include 2-hydroxybutyrate, 3-hydroxybutyrate (hereinafter referred to as 3-HB), 3-hydroxypropionate (hereinafter referred to as 3-HP), and 3-hydroxyvalerate (hereinafter referred to as 3-HV). Examples of repeating units include those derived from 3-hydroxyhexanoate (hereinafter referred to as 3-HH), 3-hydroxyheptanoate (hereinafter referred to as 3-HHEP), 3-hydroxyoctanoate (hereinafter referred to as 3-HO), 3-hydroxynonanoate (hereinafter referred to as 3-HN), 3-hydroxydecanoate (hereinafter referred to as 3-HD), 3-hydroxydodecanoate (hereinafter referred to as 3-HDd), 4-hydroxybutyrate (hereinafter referred to as 4-HB), 4-hydroxyvalerate (hereinafter referred to as 4-HV), 5-hydroxyvalerate (hereinafter referred to as 5-HV), and 6-hydroxyhexanoate (hereinafter referred to as 6-HH). The repeating units may contain one or more repeating units selected from these.

[0034] Specific examples of the polyhydroxyalkanoate include poly(3-hydroxybutyrate) (PHB), poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), poly(3-hydroxybutyrate-co-3-hydroxyvalerate-co-3-hydroxyhexanoate) (P3HB3HV3HH), poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH), poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (P3HB4HB), poly(3-hydroxybutyrate-co-3-hydroxyoctanoate), poly(3-hydroxybutyrate-co-3-hydroxyoctadecanoate), and poly(3-hydroxybutyrate-co-3-hydroxy-4-methylvalerate) (P3HB3H4MV). Among these, PHB, PHBV, P3HB3HV3HH, PHBH, and P3HB4HB are particularly preferred because they are relatively easy to produce industrially.

[0035] Among the components (a2), polylactic acid will be described in more detail. The molar ratio of lactic acid contained in this polylactic acid is preferably D-lactic acid:L-lactic acid = 100:0 to 85:15, or 0:100 to 15:85. It is also possible to blend other polylactic acids with different ratios of D-lactic acid and L-lactic acid. Only D-lactic acid or L-lactic acid may be blended. Polylactic acid, which consists solely of lactic acid as a structural unit, is a crystalline resin that tends to have a high melting point and excellent heat resistance and mechanical properties.

[0036] Furthermore, the polylactic acid may be a copolymer of the aforementioned polylactic acid with other hydroxycarboxylic acids, or may contain a small amount of units derived from a chain extender. Examples of other hydroxycarboxylic acids include optical isomers of lactic acid (D-lactic acid for L-lactic acid, and L-lactic acid for D-lactic acid), bifunctional aliphatic hydroxycarboxylic acids such as 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 2-hydroxycaproic acid, and lactones such as caprolactone, butyrolactone, and valerolactone. From the viewpoint of heat-sealing strength, it is preferable that units derived from such other hydroxycarboxylic acids be used in an amount of less than 15 mol% of the total structural units of the polylactic acid.

[0037] The weight-average molecular weight (Mw) of component (a2) is preferably at least 60,000, more preferably at least 80,000, and particularly preferably at least 100,000, and is preferably at most 700,000, more preferably at most 400,000, and particularly preferably at most 300,000. 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.

[0038] The melt flow rate (MFR) of component (a2), measured at 190°C and 2.16 kg, is preferably 0.1 g / 10 min or 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, 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 the MFR within this range, the characteristic of obtaining sufficient heat seal strength can be exhibited.

[0039] [Aliphatic-aromatic polyester resin (a3) ​​having aliphatic diol units, aliphatic dicarboxylic acid units, and aromatic dicarboxylic acid units as main structural units] The component (a3) ​​essentially contains, 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.

[0040] -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.

[0041] The aliphatic diol that provides the diol unit of formula (1) and the aliphatic dicarboxylic acid component that provides the aliphatic dicarboxylic acid unit of 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 structural units], and the preferred examples are also the same.

[0042] 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. Furthermore, examples of derivatives of aromatic dicarboxylic acids include lower alkyl esters of these aromatic dicarboxylic acids. Among these, terephthalic acid, isophthalic acid, or their lower alkyl ( For example, alkyl ester derivatives having 1 to 4 carbon atoms 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.

[0043] Specific examples of aliphatic aromatic polyester resins include polybutylene alkylate terephthalate, more preferably polybutylene adipate terephthalate or polybutylene succinate terephthalate, and particularly preferably polybutylene adipate terephthalate.

[0044] The melt flow rate (MFR) of component (a3), measured at 190°C and 2.16 kg, is preferably 0.1 g / 10 min or 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, 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 the MFR within this range, the characteristic of obtaining sufficient heat seal strength can be exhibited.

[0045] In the present invention, the aliphatic polyester resin (a) may be used alone or in combination of two or more kinds, for example, a mixture of two or more kinds of aliphatic polyester resins having different diol units or dicarboxylic acid units may be used.

[0046] The content of component (A) 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 greater than the lower limit, the heat seal strength is excellent, and when it is equal to or less than the upper limit, the storage stability of the aqueous resin dispersion is excellent.

[0047] [Plasticizer (B)] The plasticizer (B) used in the present invention is an agent used to improve the granulation properties when the resulting dry resin powder (I) is granulated, although this depends on the hardness of the polyester resin (A). Examples of the plasticizer (B) include citric acid derivatives such as triethyl citrate, tributyl citrate, acetyl triethyl citrate, and acetyl tributyl citrate, ether ester derivatives such as diethylene glycol diacetate, triethylene glycol diacetate, and triethylene glycol dipropionate, glycerin derivatives such as glycerin triacetate, glycerin tripropionate, and glycerin tributyrate, phthalic acid derivatives such as ethyl phthalyl ethyl glycolate, ethyl phthalyl butyl glycolate, and butyl phthalyl butyl glycolate, adipic acid derivatives such as mixed esters of adipic acid with 2-(2-ethoxymethoxy)ethanol and benzyl alcohol, and condensates of adipic acid with 1,4-butanediol, and polyhydroxycarboxylic acids such as polycaprolactone and polypropiolactone. Among these, those using adipic acid derivatives and phthalic acid derivatives are particularly preferred because of their high film-forming property improving effect.

[0048] The content of the plasticizer (B) is 0 to less than 12 parts by mass, preferably 0 to less than 10 parts by mass, and more preferably 0 to less than 8 parts by mass, relative to 100 parts by mass of the polyester resin (A). If the content is outside the above range, redispersibility decreases due to fusion of particles, but if it is within the range, the effects of the present invention can be achieved.

[0049] [Inorganic filler (C)] The inorganic filler (C) used in the present invention is an agent used for the purposes of preventing blocking and achieving sustained release. Examples of the inorganic filler (C) include silica such as colloidal silica, calcined silica, precipitated silica, and quartz, talc [Mg3SI4O 10 (OH)2), hard mica [KAl2(Si3Al)O 10 (OH)2), soft mica [KMg2(Si3Al)O 10 Mica such as (Na, Ca) 0.33 (Al,Mg)2SI4O 10 (OH)2·nH2O] as the main component (bentonite), kaolinite [Al2SI2O5(OH)4], montmorillonite [(Na,Ca) 0.33 (Al,Mg)2SI4O 10 Clays containing calcium carbonate (CaCO3, calcite or aragonite) as the main component (bentonite), aluminosilicate, magnesium hydrosilicate, diatomaceous earth, clay, chalk (containing 50% or more by weight of calcium carbonate (CaCO3, calcite or aragonite)), calcium carbonate, white carbon, dolomite, barium sulfate, alumina white, titanium oxide, magnesium carbonate, calcite (crystals of calcium carbonate), hydrated alumina (Al2O3H2O), gypsum such as anhydrous gypsum (CaSO4), calcined gypsum (hemihydrate gypsum CaSO4·1 / 2H2O), and dihydrate gypsum (CaSO4·2H2O), calcium sulfoaluminate (3CaO·Al2O 3·3 In particular, porous silica is particularly preferred from the viewpoint of suppressing sustained drug release.

[0050] The content of the inorganic filler (C) is 2 parts by mass or more and less than 23 parts by mass, preferably 5 parts by mass or more and less than 21 parts by mass, and more preferably 10 parts by mass or more and less than 20 parts by mass, relative to 100 parts by mass of the polyester resin (A). When the content is within the above range, the effects of the present invention can be obtained.

[0051] The average particle size of the inorganic filler (C) is preferably from 0.01 to 300 μm, more preferably from 0.05 to 250 μm, and particularly preferably from 0.1 to 200 μm. If the average particle size is too large, the density of the coating film after re-emulsification tends to decrease, whereas if it is too small, the effect of preventing blocking tends to decrease. Blocking is likely to occur when the dry resin powder (I) according to the present invention is loaded during transportation, storage, etc., and is subjected to load. If blocking occurs, when the dry resin powder (I) is re-emulsified, the average particle size of the dispersion in the emulsified state is likely to be insufficiently small, and the particles are likely to be insufficiently dispersed, which may result in insufficient stability of the re-emulsified liquid. The average particle size is measured using an electron microscope, an optical microscope, a dry particle size measuring instrument, or the like.

[0052] The BET specific surface area of ​​the inorganic filler (C) is 0.005 to 800 m 2 When silica is used as the inorganic filler (C), the BET specific surface area is preferably 50 to 800 m 2 / g is preferable, and 80 to 700m 2 / g is preferable, and 100 to 600m 2 / g is preferred.

[0053] The inorganic filler (C) can be incorporated in the composition by the following methods. (1) A method in which an inorganic filler (C) is premixed with an aqueous resin emulsion containing the polyester resin (A) and a plasticizer (B), and more preferably a nonionic dispersant (D), to obtain an aqueous resin dispersion (i), and then the aqueous resin dispersion (i) is spray-dried. (2) A method in which, during the spray drying of the resin emulsion, the inorganic filler (C) is sprayed from a nozzle separate from the resin emulsion and mixed with the resin emulsion while powdering the powder. (3) A method in which the resin emulsion is spray-dried to obtain a resin powder, and an inorganic filler (C) is mixed with the resin powder using a Nauta mixer or the like. These methods can also be combined. For example, methods (2) and (3) can be combined, in which a portion of the inorganic filler (C) is first mixed and added by method (2), and then the remainder of the inorganic filler (C) is mixed by method (3). Among these, a combination of methods (2) and (3) in which a part of the inorganic filler (C) is first added by method (2) and then the remainder of the inorganic filler (C) is mixed by method (3) is preferred, since it allows the full effect of blending the inorganic filler (B) to be obtained.

[0054] [Nonionic dispersant (D)] The nonionic dispersant (D) according to the present invention is mainly used in obtaining the aqueous resin dispersion (i). It is an agent used to stabilize the dispersion of component (A), and can also disperse components (B) and (C) in an aqueous medium. The nonionic dispersant (D) may be any commonly used, well-known nonionic dispersant. Examples include nonionic water-soluble polymers and nonionic surfactants. These may be used alone or in combination of two or more.

[0055] 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 ethers and the above unsaturated acids, and salts of the above copolymers.

[0056] Examples of the nonionic surfactant include nonionic surfactants, and specific examples thereof include, but are not limited to, 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, polyoxyethylene stearyl amino ether, and other polyoxyethylene alkyl amino ethers. Among these, PVA-based resins are preferably used from the viewpoint of enhancing the stability of the aqueous resin dispersion.

[0057] [Polyvinyl alcohol resin (d)] Among the nonionic dispersants (D), the polyvinyl alcohol-based resin (PVA-based resin) (hereinafter, sometimes referred to as "polyvinyl alcohol-based resin (d) (or PVA resin (d)")) will be described in a little more detail. Examples of the polyvinyl alcohol-based resin (d) (PVA-based resin (d)) include 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").

[0058] 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, and vinyl stearate, with vinyl acetate being preferred. The vinyl ester compounds may be used alone or in combination of two or more.

[0059] 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 ethylene olefins such as propylene, isobutylene, α-octene, α-dodecene, and α-octadecene; hydroxyl group-containing α-olefins such as 3-buten-1-ol, 4-penten-1-ol, and 5-hexen-1-ol, and derivatives thereof such as acylated products; unsaturated acids such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, maleic anhydride, itaconic acid, and undecylenic acid, their salts, monoesters, and dialkyl esters; amides such as diacetone acrylamide, acrylamide, and methacrylamide; olefin sulfonic acids such as ethylene sulfonic acid, allyl sulfonic acid, and methallyl sulfonic acid, or their salts. These can be used alone or in combination of two or more.

[0060] Furthermore, 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 and a PVA resin having a 1,2-diol structural unit in the side chain.

[0061] The average saponification degree of the PVA resin (d) is preferably 70 mol% to 100 mol%, more preferably 75 to 99 mol%, even 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 using the aqueous resin dispersion tends to decrease.

[0062] In particular, when an unmodified PVA resin is used as the PVA resin (d), the average saponification degree is preferably 70 to 100 mol%, more preferably 75 to 95 mol%, and even more preferably 75 to 90 mol%. If the average saponification degree is too low, the water resistance of the film obtained using the aqueous resin dispersion tends to decrease.

[0063] When a modified PVA resin is used as the PVA resin (d), the average saponification degree thereof 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 using the aqueous resin dispersion tends to decrease. The average degree of saponification is measured in accordance with JIS-K-6726-3.5.

[0064] The viscosity of a 4% by mass aqueous solution of the PVA resin (d) 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.

[0065] When an unmodified PVA resin is used as the PVA resin (d), the viscosity of a 4% by 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.

[0066] Furthermore, when a modified PVA resin is used as the PVA resin (d), the viscosity of a 4% by 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 mass % aqueous solution (viscosity) is measured in accordance with JIS-K-6726-3.11.2.

[0067] The average degree of polymerization of the PVA-based resin (d) is preferably 50 to 5,000. It is more preferably 150 to 4000, even more preferably 300 to 3000, and particularly preferably 1000 to 3000. 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.

[0068] In the present invention, the PVA-based resin (d) can be used alone or in combination with other unmodified PVA-based resins, modified PVA-based resins, or an unmodified PVA-based resin and a modified PVA-based resin. Furthermore, two or more PVA-based resins having different average saponification degrees, viscosities, modified species, modification amounts, etc. can also be used in combination.

[0069] The content of the nonionic dispersant (D) is 0.1 parts by mass or more and 50 parts by mass or less per 100 parts by mass of the polyester resin (A) and plasticizer (B). It is preferably 4 parts by mass or more, and more preferably 5 parts by mass or more. The upper limit is preferably 40 parts by mass or less, and more preferably 30 parts by mass or less. When the content is within the above range, the effects of the present invention can be obtained.

[0070] The content of the nonionic dispersant (D) component relative to the total amount of the aqueous resin dispersion 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. It is also preferably 50% by mass or less, more preferably 40% by mass or less, even more preferably 30% by mass or less, and particularly preferably 25% by mass or less. If the content is lower than this range, the stability of the aqueous resin dispersion tends to decrease. If the content is higher than this range, the water resistance of the film obtained using the aqueous resin dispersion tends to decrease.

[0071] [Dispersion medium (E)] The powder composition of the present invention can be redispersed in, for example, a dispersion medium (E). Such a dispersion medium (E) is not particularly limited, as long as it is an aqueous medium or an aqueous solution in which a water-soluble component is dissolved in water, within a substance and concentration range that does not generally affect the stability of the aqueous resin dispersion. Examples of aqueous media include water and water-soluble organic solvents, and examples of aqueous solutions in which a water-soluble component is dissolved in water include aqueous polysaccharide solutions and aqueous cellulose solutions. Rather than using a water-soluble organic solvent directly, it is preferable to use a water-soluble organic solvent in combination with water, preferably a water-soluble organic solvent in combination with a small amount of water. Examples of such water-soluble organic solvents include methanol, ethanol, acetone, and isopropyl alcohol. Of these, water is the most preferred dispersion medium.

[0072] The content of component (E) 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 greater than the lower limit, the storage stability of the aqueous resin dispersion is excellent, and when it is equal to or less than the upper limit, the heat seal strength is excellent.

[0073] When the dispersion medium is a combination of water and an organic solvent, the content of water relative to 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. Of these, it is most preferable to use only water as the dispersion medium.

[0074] [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 may include, for example, preservatives, antifungal agents, antibacterial agents, thermoplastic resins, various stabilizers, ultraviolet absorbers, Examples of the dispersion medium include light stabilizers, antioxidants, antistatic agents, rust inhibitors, curing agents, fillers, thickeners, etc. Furthermore, examples of the dispersion medium include dispersion mediums containing a solute such as a polysaccharide aqueous solution and a cellulose aqueous solution, but when a dispersion medium containing a solute is used as the dispersion medium, the solute is treated as another component.

[0075] [Method for producing aqueous resin dispersion (i)] The aqueous resin dispersion (i) used in the present invention can be produced by a known method in the art, such as a phase inversion emulsification method, a high-pressure emulsification method, or a solvent substitution method. The emulsification method involves melt-kneading a polyester resin (A) and then adding a nonionic dispersant (D) and a dispersion medium (E) to the melt-kneaded composition and then performing a phase inversion emulsification process. The high-pressure emulsification method involves dispersing a polyester resin (A), a plasticizer (B), a nonionic dispersant (D), and a dispersion medium (E) by heating and stirring under pressure. The solvent replacement method involves dissolving a polyester resin (A), a nonionic dispersant (D), and a dispersion medium (E) in an organic solvent, adding the mixture, stirring, and dispersing the mixture, and then removing the organic solvent. In these methods, an inorganic filler (C) may be added as needed.

[0076] Specifically, a polyester resin (A) and a plasticizer (B) are placed in a kneader, and optionally a solvent is added, followed by melt-kneading under heating conditions. A nonionic dispersant (D) such as a PVA resin and a dispersion medium such as water are then added, and these components are mixed and phase-inverted to emulsify.

[0077] 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.

[0078] When producing using an extruder, for example, a dispersoid (polyester resin (A)) containing an aliphatic polyester resin (a) is continuously fed from the hopper of the extruder or from a separate feed port, and melt-kneaded under heating conditions; a nonionic dispersant (D) such as a PVA resin, a dispersion medium such as water, and, if necessary, an inorganic filler (C) are added from another feed port provided in the extruder; the mixture is kneaded and dispersed to undergo phase inversion emulsification, and then continuously extruded from a die, thereby obtaining an aqueous resin dispersion according to an embodiment of the present invention. In addition to this stage, the inorganic filler (C) may be added when obtaining the dry resin powder (I) or after obtaining the dry resin powder (I), as described above.

[0079] [Aqueous resin dispersion (i)] The aqueous resin dispersion of this embodiment obtained as described above is an aqueous resin dispersion. Such an aqueous resin dispersion (i) is a dispersion of particulate matter 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 extremely low solubility. In the aqueous resin dispersion (i) of this embodiment, the polyester resin (A) containing the aliphatic polyester resin (a) is the dispersoid, and these are dispersed in an aqueous solvent.

[0080] The dispersed particle size of the dispersoid in the aqueous resin dispersion (i) 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 size within this range, the aqueous resin dispersion can exhibit its excellent storage stability. The dispersed particle size is the median size (d50) corresponding to 50% of the cumulative particle size distribution on a volume basis, and can be measured, for example, using a laser diffraction particle size measuring device (e.g., product number LA-950 Measurements can be performed using a hologram analyzer (V2, manufactured by Horiba Ltd.).

[0081] In order to further improve the biodegradability of the aqueous resin dispersion (i) 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 (D), and it is particularly preferable to use a PVA resin as the nonionic dispersant (D).

[0082] The average particle size of the dispersed particles in the aqueous resin dispersion (i) is preferably 0.1 to 100 μm, more preferably 0.5 to 50 μm. By adjusting the size within this range, the dispersion can be stabilized.

[0083] [Dry resin powder (I)] The dry resin powder (I) of the present invention is obtained by drying the above aqueous resin dispersion (i). The method of the present invention provides a re-emulsifiable powder obtained by drying a composition containing the above-mentioned components. The drying method is not particularly limited, and examples thereof include spray drying, freeze drying, and hot air drying after coagulation. Among these, spray drying is preferred from the viewpoints of production cost and energy conservation. In the case of spray drying, the spraying method is not particularly limited, and can be carried out using, for example, a disk type or a nozzle type. Examples of heat sources for spray drying include hot air and heated steam. The spray drying conditions can be appropriately selected depending on the size and type of the spray dryer, the solid content, viscosity, flow rate, etc. of the aqueous emulsion. The spray drying temperature is typically about 80 to 150°C.

[0084] To further explain the spray drying process using a specific example, first, the solid content of the synthetic resin emulsion is adjusted, and then the emulsion is continuously fed through the nozzle of the spray dryer, and the atomized product is dried with hot air to form a powder. In some cases, the adjusted spray liquid can be heated before spraying and continuously fed through the nozzle, and the atomized product can be dried with hot air to form a powder. Heating increases the drying speed, and the reduced viscosity of the spray liquid allows for the spray liquid to become highly non-volatile, which also contributes to reducing production costs. If the concentration of the composition before spray drying (concentration of components other than the solvent) is too dilute, it is easy to control the particle size during spraying, but drying efficiency will be poor, and if it is too concentrated, drying efficiency will be good, but particle size control during spraying will be difficult. For this reason, the proportion of components other than the solvent is preferably 20% by weight to 70% by weight, more preferably 30% by weight to 60% by weight.

[0085] The dry resin powder (I) of the present invention is usually spherical secondary particles formed by spray-drying one drop of the aqueous resin dispersion (i). The average particle size is preferably 5 to 500 μm, more preferably 10 to 300 μm, and this average particle size is also the average particle size of secondary particles.

[0086] [Re-emulsification of dried resin powder (I)] The dried resin powder (I) of the present invention can be re-emulsified by adding the aqueous medium and dispersing it in water to form an aqueous resin dispersion again (in this specification, this re-emulsified aqueous resin dispersion may be referred to as a "re-emulsified aqueous resin dispersion"). At this time, it is preferable that secondary particles are also dissolved to form an emulsion of primary particles. The dispersion ratio of the re-emulsified aqueous resin dispersion, i.e., the ratio of the average particle size of the re-emulsified aqueous resin dispersion to the average particle size of the aqueous resin dispersion (i) before drying, is preferably less than 800%, and more preferably less than 500%, of the average particle size of the aqueous resin dispersion (i) before drying. By keeping the dispersion ratio within this range, the characteristic of exhibiting physical properties at the same level as those of the aqueous resin dispersion (i) before spray drying can be exhibited.

[0087] [Application] The uses of the powder composition and re-emulsified aqueous resin dispersion according to an embodiment of the present invention are not limited to the following, and they can be used in the form of molded articles (e.g., films) molded using the re-emulsified aqueous resin dispersion by known molding methods. For example, they can be used as adhesives, pressure-sensitive adhesives, their modifiers, coating agents, heat-sealing agents, paints, paint primers, inks, binders, etc. in paper, films, sheets, structural materials, building materials, automotive parts, electrical and electronic products, packaging materials, clothing, pharmaceuticals, cosmetics (e.g., shampoos, rinses, emulsions, lotions, perfumes), agricultural compositions (e.g., pesticide emulsions), health foods, and foods. Cosmetics, agricultural compositions, paints, inks, or adhesives containing the aqueous resin dispersion according to an embodiment of the present invention are particularly preferred. Furthermore, the re-emulsified aqueous resin dispersion according to an embodiment of the present invention is suitable as a coating agent for coated objects (objects to be coated) due to its excellent heat-sealing properties and film-forming properties. The heat-sealing property 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. [Example]

[0088] 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 by mass.

[0089] The following components were prepared: <Polyester-based resin (component (A))> Polyester resin (A-1): Polybutylene succinate adipate (a1) ["BIoPBS (FD92)" manufactured by PTT MCC BIochem, melt flow rate (MFR) 4 g / 10 min (190°C, 2.16 kg), melting point 86°C] (hereinafter referred to as "PBSA")

[0090] <Plasticizer (B)> Mixed-group dibasic acid ester [DAIFATTY-101 manufactured by Daihachi Chemical Industry Co., Ltd.] (hereinafter referred to as "D-101")

[0091] <Nonionic dispersant (D)> PVA resin (d1) (unmodified PVA resin, average degree of polymerization 2000, degree of saponification 78.5 to 81.5%, 4% by mass viscosity at 20°C 44.0 to 52.0 mPa s) (hereinafter referred to as "PVOH")

[0092] <Inorganic filler (C)> A mixture of magnesium silicate hydrate (talc) and calcium magnesium carbonate (dolomite) ["Incomp SE Super" manufactured by euroMinerals GmbH] (hereinafter referred to as "talc"). Porous silica having a particle size of approximately 14 μm, available from Evonik Industries AG [SIPERNAT® 22S] (hereinafter referred to as “silica”) Synthetic mica with a particle size of approximately 8 μm available from Nihon Koken Kogyo Co., Ltd. [NS-8] (hereinafter referred to as "mica")

[0093] [Examples 1 to 7, Comparative Examples 1 to 6] (Production of aqueous resin dispersion (i)) The polyester resin (A-1) (and the plasticizer (B) in Comparative Examples 2, 4 to 6) was continuously fed from the hopper of a twin-screw extruder (TEX30HSS, manufactured by The Japan Steel Works, Ltd.) and melted at a heating temperature (cylinder temperature) of 120 to 220°C. Next, a PVA resin (d1) as a dispersant and water as a dispersion medium were continuously fed from a feed port provided in the extruder, while the mixture was continuously extruded (screw rotation speed: 300 rpm) at a heating temperature (cylinder temperature) of 90 to 105°C, to obtain an aqueous resin dispersion (i) having the mass ratio shown in Table 1. The dispersed particle diameter (median diameter) of the resulting aqueous resin dispersion (i) was measured using a laser diffraction particle diameter measuring device (LA-950V2, manufactured by Horiba, Ltd.) and was 2.4 μm in all cases.

[0094] (Preparation of dry resin powder (I)) The aqueous synthetic resin emulsion obtained above was spray dried in a 140°C airflow atmosphere. The mixture was dried while being sprayed using a sprayer to obtain a dry resin powder (I) (re-emulsifiable synthetic resin powder). In the cases where inorganic filler (C) was contained (Examples 2 to 4, Comparative Example 1), the talc was used in the mass ratio shown in Table 1 relative to 100 parts by mass of the obtained aqueous synthetic resin dispersion (i), and the aqueous synthetic resin dispersion (i) and inorganic filler (C) were mixed while being spray-dried using separate spray atomizers in an airflow atmosphere at 140°C, to obtain dried resin powder (I) (reemulsifiable synthetic resin powder). The obtained dried resin powder (I) was used to carry out the following evaluations. The results are shown in Table 1.

[0095] [Redispersibility (redispersion rate) evaluation] Five parts of ion-exchanged water was added to 5 parts of the obtained dried resin powder (I) or powder composition, and the mixture was stirred with a stirrer for 24 hours to redisperse. The dispersed particle size (median size) in the obtained redispersion was measured using a laser diffraction particle size analyzer (LA-950V2, manufactured by Horiba, Ltd.). The particle size was compared with the particle size of the dispersed particles in the aqueous resin dispersion (i) before drying, and the rate of change was calculated using the following formula and evaluated according to the following criteria. Redispersion rate (%) = average particle size of dispersed particles in redispersion liquid / average particle size of dispersed particles in aqueous resin dispersion (i) before drying × 100 (Evaluation criteria) ○ Less than 800% × 800% or more

[0096] [Heat sealability evaluation] The resulting aqueous resin dispersion (i) was applied at a rate of 7 g / m² to one side of a 50 g / m² glossy bleached kraft paper using a bar coder and dried at 100°C for 20 seconds. The resulting coated paper was cut into strips 15 cm long and 15 mm wide, and the coated surfaces were placed together and heat-sealed at 150°C, 1.3 kg / cm² pressure, and 1 second to obtain test pieces (coated paper). This test piece was used to conduct a 180° peel test at a tensile speed of 200 mm / min using a tensile tester (MinebeaMitsumi, PT-200N), and the results were evaluated according to the following criteria. (Evaluation Criteria) ○ 3.5N / 15mm or more ×...Less than 3.5N / 15mm

[0097] [Blocking resistance rating 1] A stainless steel cylindrical container a with an inner diameter of 45 mm and a height of 100 mm was placed on a glass plate and 50 g of re-emulsifiable dry resin powder (I) was added. A stainless steel cylindrical container b with an outer diameter of 45 mm and a height of 80 mm, adjusted to a total weight of 500 g, was then placed inside container a. This was placed horizontally in a thermo-hygrostat adjusted to a temperature of 40°C and a humidity of 60% and left to stand for 16 hours. It was then removed from the thermo-hygrostat and allowed to cool at room temperature for 2 hours. Then, containers a and b were gently removed and the state of solidification of the re-emulsifiable dry resin powder (I) was examined. The evaluation criteria were as follows:

[0098] [Blocking resistance rating 2] A stainless steel cylindrical container a with an inner diameter of 45 mm and a height of 100 mm was placed on a glass plate and 50 g of re-emulsifiable dry resin powder (I) was added. A stainless steel cylindrical container b with an outer diameter of 45 mm and a height of 80 mm, adjusted to a total weight of 800 g, was then placed inside container a. This was placed horizontally in a thermo-hygrostat adjusted to a temperature of 50°C and a humidity of 60%, and left to stand for 16 hours. It was then removed from the thermo-hygrostat and allowed to cool at room temperature for 2 hours. Then, containers a and b were gently removed, and the state of solidification of the re-emulsifiable dry resin powder (I) was examined. The evaluation criteria were as follows:

[0099] (Blocking resistance test evaluation criteria) A: When the tube is removed, no sample remains in the tube and there is no blocking at all. Alternatively, no sample remains in the tube, but there are agglomerates in the sample that can be easily broken down by hand. B: When the tube is removed, the sample remains inside the tube, but crumbles into powder when removed from the tube. C: When the tube is removed, the sample remains inside the tube, and the sample removed from the tube has a cylindrical shape, but it collapses when you try to lift it by grabbing the top. D: When the tube is removed, the sample remains inside the tube, and the solidified sample can be grasped by the top and lifted up, but it easily crumbles into powder by hand. E: When the tube is removed, the sample remains in the tube, and some of the solidified sample removed from the tube can be crushed into powder by hand, while others cannot be crushed by hand. F: When the tube is removed, the sample remains inside the tube, and the solidified sample removed from the tube cannot be crushed by hand.

[0100] (Creating pesticide granules) Five parts of bisphenol A as a model substance of pesticides, 20 parts of dry resin powder (I) as a binder, 22.5 parts of bentonite (WK-5, manufactured by Neolite Kosan Co., Ltd.) as a layered silicate, and 52.5 parts of calcium carbonate (calcium carbonate for granules, manufactured by Neolite Kosan Co., Ltd.) as an inorganic filler were placed in a polyethylene bag and shaken and mixed for 3 minutes. 100 parts of the above powder was mixed with 33.3 parts of ion-exchanged water and the mixture was put into a wet extrusion granulator (BENCHTOP manufactured by Tsutsui Scientific Instruments Co., Ltd.). The mixture was extrusion-granulated using a GRANULATOR to obtain granules. The obtained granules were dried at 80°C for 1 hour to obtain a granular agricultural composition (granules). The obtained granules were subjected to the following dissolution rate measurement.

[0101] [Measurement method for sustained release rate] 0.5 parts of the granules obtained above were placed in 250 mL of deionized water and allowed to soak. The mixture was stored at 25°C, and after 1 day, 3 days, and 7 days, the supernatant was removed and filtered. The elution rate (%) of bisphenol A was measured using high performance liquid chromatography (HPLC) under the following measurement conditions, and the shape of the granules was visually observed and evaluated according to the following criteria.

[0102] (HPLC measurement conditions) ·Equipment: LC-2030C 3D Shimadzu Corporation Column: ODS Column temperature: 40℃ ·Mobile phase: water / CH3CN=60 / 40 ·Flow rate: 1mL / min ·Injection volume: 10μL Detector: PDA (200 nm)

[0103] (Evaluation criteria for dissolution rate) ○ Less than 80% dissolved in 2 weeks × More than 80% dissolved after 2 weeks (Granule shape evaluation criteria) 〇 Maintains its shape × Partially or completely collapsed

[0104] [Table 1]

Claims

1. A powder composition containing a polyester-based resin (A), the polyester resin (A) is an aliphatic polyester resin, The powder composition contains 0 parts by mass or more and less than 12 parts by mass of a plasticizer (B) and 2 parts by mass or more and less than 23 parts by mass of an inorganic filler (C) relative to 100 parts by mass of the polyester-based resin (A).

2. 2. The powder composition according to claim 1, wherein the polyester resin (A) contains 50 mol % or more of a structure derived from an aliphatic polyol and / or an aliphatic dicarboxylic acid.

3. 2. The powder composition according to claim 1, wherein the polyester resin (A) is polybutylene succinate and / or polybutylene succinate adipate.

4. 2. The powder composition according to claim 1, further comprising a non-ionic dispersant (D).

5. 5. The powder composition according to claim 4, wherein the nonionic dispersant (D) is a polyvinyl alcohol-based resin.

6. 6. The powder composition according to claim 5, wherein the polyvinyl alcohol resin has an average degree of polymerization of 50 to 5,000.

7. 5. The powder composition according to claim 4, wherein the content of the nonionic dispersant (D) is 0.1 parts by mass or more and 50 parts by mass or less per 100 parts by mass of the total amount of the polyester resin (A) and the plasticizer (B).

8. An agricultural composition comprising the powder composition of claim 1.

9. A re-emulsified aqueous resin dispersion comprising the resin powder according to claim 1 and an aqueous medium.

10. A coating agent comprising the re-emulsified aqueous resin dispersion according to claim 9.

11. A method for producing a powder composition containing a dried resin powder (I) obtained by drying an aqueous resin dispersion (i) containing a polyester-based resin (A), comprising: the polyester resin (A) is an aliphatic polyester resin, the composition contains 0 parts by mass or more and less than 12 parts by mass of a plasticizer (B) relative to 100 parts by mass of the polyester-based resin (A), and 0.1 to 30 parts by mass of a nonionic dispersant (D) relative to 100 parts by mass of the total amount of the polyester-based resin (A) and the plasticizer (B); A method for producing a powder composition, comprising: a powder composition containing 2 parts by mass or more and less than 23 parts by mass of an inorganic filler (C) per 100 parts by mass of the dry resin powder (I).

12. The method for producing a powder composition according to claim 11, wherein the dispersion medium of the aqueous resin dispersion (i) is water.

13. 12. The method for producing a powder composition according to claim 11, wherein the particle size of the dry resin powder (I) when dispersed in water is less than 800% of the particle size of the aqueous resin dispersion (i).

14. The method for producing a powder composition according to claim 11, characterized in that the aqueous resin dispersion (i) is spray-dried.

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