JP2012233023A - Sustained-release biodegradable coating agent and body with sustained-release biodegradable coat - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sustained-release biodegradable coating agent comprising a polylactic acid-based resin having self-emulsification function of forming stable aqueous dispersion without adding an emulsifier, and a body with the sustained-release biodegradable coat, because: it is convenient that when a polylactic acid-based biodegradable resin to be used as a coating agent is able to form an aqueous dispersion, the biodegradable coated body can be readily obtained by a method comprising dissolving or dispersing the component to be coated into the aqueous dispersion, and then spraying the aqueous dispersion itself to vaporize moisture into a particle form, or the like; and it is preferable that when the polylactic acid-based biodegradable resin is self-emulsifiable one that can form aqueous dispersion without adding a surfactant, there occurs no release of surfactants in the environment during the biodegrading process so as to reduce environmental load.SOLUTION: This sustained-release biodegradable coating agent comprises a copolymer polyurethane resin having a polylactic acid segment and a sulfonate group-containing segment in the molecule. The body with the sustained-release biodegradable coat is obtained by coating a component to be coated with the coating agent.

Description

    The present invention relates to a sustained-release biodegradable coating agent comprising a copolymer polyurethane resin having a polylactic acid segment and a sulfonate group-containing segment in the molecule, and a sustained-release biodegradable coating body coated with the component to be coated thereby About. Here, the sustained-release biodegradable coating agent is gradually decomposed by organisms such as microorganisms in the natural environment such as the surface and inside of soil, river lakes and oceans, etc. It refers to a coating material that exhibits an action of continuously releasing over a wide range. In addition, the component to be coated is, for example, a biocide, a pest repellent or attractant, and / or a plant growth regulator.

    It has been conventionally known that a pesticide or a fertilizer is coated with a polylactic acid-based biodegradable resin to form a sustained-release agrochemical or a slow-release fertilizer (eg, Patent Documents 1 and 2). In addition, it is known to prevent biofouling of ship bottoms, underwater structures, fish nets, etc. using a paint containing a bioadhesion inhibitor and a binder comprising a polylactic acid-based biodegradable resin (for example, Patent Document 3, 4). However, none of the polylactic acid-based biodegradable resins exhibits water dispersibility without the use of a surfactant, and in order to form an aqueous dispersion, the use of a surfactant is essential.

Japanese Patent Laid-Open No. 11-286403 JP 2001-146570 A JP 2001-064089 A JP-A-11-106304

    If the polylactic acid-based biodegradable resin used as a coating agent can form an aqueous dispersion, the components to be coated are dissolved or dispersed in the aqueous dispersion, and then the water dispersion itself is sprayed to evaporate the water. Can be made into particles, sprayed in the presence of some carrier, adhered to the surface of the carrier and / or inside the carrier, or applied to some adherend to form a coating film, making it easily biodegradable coating The body can be obtained and is convenient. Moreover, if the polylactic acid-based biodegradable resin is a self-emulsifying agent that can form an aqueous dispersion without the addition of a surfactant, the surfactant is released into the environment during the biodegradation process. This is preferable because there is less environmental impact.

The present invention has been made against the background of such prior art problems. That is, the problem to be solved by the present invention is to provide a sustained-release biodegradable coating agent comprising a polylactic acid-based resin having a self-emulsifying function capable of forming a stable aqueous dispersion without adding an emulsifier, and It is to provide a sustained release biodegradable coating. The present invention has the following configuration.
(1) A sustained-release biodegradable coating agent comprising a copolymer polyurethane resin having a polylactic acid segment and a sulfonate group-containing segment in the molecule.
(2) The sustained-release biodegradable coating agent according to (1), wherein the sulfonate group-containing segment is a copolymer polyester.
(3) The sustained release property according to (1) or (2), wherein the sulfonate group is one or more of a sulfonate metal base, a sulfonate quaternary ammonium base, or a sulfonate quaternary sulfonium base. Biodegradable coating.
(4) A polylactic acid diol (A), a sulfonate group-containing diol (B), and a diol (C) other than (A) and (B) are combined by a polyaddition reaction with a diisocyanate compound (D). A sustained-release biodegradable coating agent comprising a copolymer polyurethane resin.
(5) The sustained-release biodegradable coating agent according to any one of (1) to (4), wherein the concentration of the sulfonate group is 50 eq / ton or more and 500 eq / ton or less.
(6) The sustained-release biodegradable coating according to (4), wherein the diol (C) contains 2,2-dimethyl-3-hydroxypropyl-2 ′, 2′-dimethyl-3′-hydroxypropanoate. Agent.
(7) The sustained release biodegradable coating agent according to (4), wherein the diol (C) contains a polyether diol.
(8) The sustained-release product according to (4), wherein 0.1 mol% or more and 5 mol% or less of the total of the diols (A), (B), and (C) is substituted with a tri- or more functional polyol. Degradable coating.
(9) The sustained-release biodegradable coating agent according to (4), wherein 0.1 mol% or more and 5 mol% or less of the diisocyanate compound (D) is substituted with a tri- or more functional polyisocyanate.
(10) The molar ratio (L / D) of L-lactic acid and D-lactic acid constituting the diol (A) is 1 to 9, and the L-lactic acid residue and the D-lactic acid residue with respect to the diol (A) The sustained-release biodegradable coating agent according to (4), wherein the total weight fraction is 50% by weight or more.
(11) A sustained-release biodegradable coated body in which a component to be coated is coated with the biodegradable coating agent according to any one of (1) to (10).
(12) The sustained-release biodegradable coating according to (11), wherein the component to be coated has one or more functions of insecticidal, herbicidal, sterilizing, antifungal, biological attraction and biological repellent. body.
(13) The sustained-release biodegradable coating according to (11), wherein the component to be coated has one or more functions of biological activity, growth promotion, and nutritional supplementation for living organisms.

    Since the biodegradable coating agent of the present invention has an appropriate biodegradation rate, when it is left in the natural environment, it is gradually biodegraded over a long period of time, and gradually releases the components to be coated into the environment. . For this reason, a coated body formed by coating a coating agent such as a fertilizer, agricultural chemical, antifungal agent, bactericidal agent, biological repellent with the biodegradable coating agent of the present invention is excellent in sustained release of the coating agent. . Moreover, the biodegradable coating agent of this invention can form the water dispersion excellent in film forming property in the preferable embodiment, and can be used with the form of a coating film.

<Slow release biodegradable coating>
The sustained-release biodegradable coating in the present invention is obtained by coating the component to be coated with the sustained-release biodegradable coating in the present invention. The sustained-release biodegradable coating of the present invention may contain components other than the component to be coated and the sustained-release biodegradable coating of the present invention. For example, other biodegradable resins, Biodegradable resins, hydrolysis accelerators, hydrolysis inhibitors, and the like may be blended. The sustained-release biodegradable coating refers to those in which the component to be coated is coated with a sustained-release biodegradable coating, but only the same component as the component to be coated is present inside the coating. Not only those that also adhere to the outer surface.

    The sustained-release biodegradable covering in the present invention is gradually decomposed by organisms such as microorganisms in the natural environment such as the surface and the inside of soil, river lakes, and the ocean, etc. It exhibits the effect of continuously releasing over a long period. For this reason, it can be used as a sustained-release agrochemical, slow-acting fertilizer, long-lasting antifouling paint, etc. by selecting an appropriate component to be coated.

<Coated components>
The component to be coated in the present invention is not particularly limited as long as it is a component that is desired to be gradually released in the natural environment. Specific examples of the component to be coated in the present invention include a component that can be expected to have a biological control action such as insecticidal, herbicidal, sterilizing, antifungal, biological attraction and biological repellent, and a growth promoting action on living organisms such as bioactive substances and fertilizers. And / or a component that can be expected to have a nutritional supplement. Further, the component to be coated is not limited to a single component, and may be composed of a plurality of components.

<Slow release biodegradable coating agent>
The sustained-release biodegradable coating agent of the present invention comprises a copolymer polyurethane resin having a polylactic acid segment and a sulfonate group-containing segment in the molecule. The sulfonate group-containing segment is preferably made of a copolyester, and the sulfonate group is one or more of a sulfonate metal base, a sulfonate quaternary ammonium base, or a sulfonate quaternary sulfonium base. It is preferable. The copolymer polyurethane resin comprises a polylactic acid diol (A), a sulfonate group-containing diol (B), a diol (C) other than (A) and (B), and a polyaddition reaction with a diisocyanate compound (D). It is preferable that it consists of the structure couple | bonded by.

    The sulfonate group-containing segment (B) copolymerized with the copolymer polyurethane resin of the present invention is a polyester having a chemical structure obtained by a condensation reaction between a dibasic acid having a sulfonate group or a diester compound thereof and a glycol component. A diol compound is preferred. Preferable examples of the sulfonic acid base include a sulfonic acid metal base, a sulfonic acid quaternary ammonium base, and a sulfonic acid quaternary phosphonium base. Examples of the sulfonic acid metal base include lithium salt, sodium salt, potassium salt and the like. Examples of the sulfonic acid quaternary ammonium base and the sulfonic acid quaternary phosphonium base include tetraalkylammonium salts and tetraalkylphosphonium salts, wherein the alkyl group is preferably an alkyl group having 1 to 8 carbon atoms, It does not necessarily have to be composed of one kind of alkyl group.

    The dibasic acid having a sulfonate group is one selected from isophthalic acid-5-sulfonate, terephthalic acid-3-sulfonate, and 1,8-naphthalenedicarboxylic anhydride-4-sulfonate. The above is preferable.

（但し、Ｒは炭素数２〜５の２価の飽和脂肪族炭化水素基、ＭはＬｉ、Ｎａ、Ｋ、四級アンモニウムまたは四級ホスホニウム、ｍは正の整数、ｎは正の整数、ｍ＋ｎは２〜１０の整数を示す）
なお、前記一般式（１）において、前記四級アンモニウムとしては下記一般式（２）、前記四級ホスホニウムとしては下記一般式（３）であることが好ましい。

（但し、Ｒ１、Ｒ２、Ｒ３、Ｒ４は同一であっても異なってもよい炭素数１〜１８の炭化水素基を示す）

（但し、Ｒ５、Ｒ６、Ｒ７、Ｒ８は同一であっても異なってもよい炭素数１〜１８の炭化水素基を示す） The diester compound of dibasic acid having a sulfonate group is selected from isophthalic acid-5-sulfonate, terephthalic acid-3-sulfonate, and 1,8-naphthalenedicarboxylic anhydride-4-sulfonate. It is preferable that it is the diester compound of the dibasic acid which is 1 or more types. Moreover, it is preferable that it is a diester compound with monoalcohols, such as methanol and ethanol, or a diester compound with diols, such as ethylene glycol and propylene glycol. In particular, a compound represented by the following general formula (1) is particularly preferable from the viewpoint of versatility of raw materials.

(Where R is a divalent saturated aliphatic hydrocarbon group having 2 to 5 carbon atoms, M is Li, Na, K, quaternary ammonium or quaternary phosphonium, m is a positive integer, n is a positive integer, m + n Represents an integer of 2 to 10)
In the general formula (1), the quaternary ammonium is preferably the following general formula (2), and the quaternary phosphonium is preferably the following general formula (3).

(However, R1, R2, R3, and R4 represent the same or different hydrocarbon group having 1 to 18 carbon atoms)

(However, R5, R6, R7 and R8 represent the same or different hydrocarbon group having 1 to 18 carbon atoms)

    Hereinafter, in the copolymer polyurethane resin of the present invention, the case where a sulfonic acid metal base is used as the sulfonic acid group in the molecule will be described in detail as a representative.

    The copolymer polyurethane resin of the present invention has a sulfonic acid metal base in the molecule and exhibits a self-emulsifying function with the sulfonic acid metal base to form small aqueous dispersion particles. The concentration of the sulfonic acid metal base is preferably 50 eq / ton or more and 500 eq / ton or less, more preferably 100 eq / ton or more and 300 eq / ton or less, and still more preferably 150 eq / ton or more and 260 eq / ton or less. When the sulfonic acid metal base concentration is too low, the particle size of the aqueous dispersion particles formed is increased, and the storage stability and coating suitability are lowered. Moreover, when the sulfonic acid metal base concentration is too high, the solution viscosity of the polyurethane solution tends to be high, and the polymerization reaction tends to be difficult. The coating suitability mentioned here refers to the property that a smooth coat layer excellent in transparency can be obtained when an emulsion liquid is applied onto a substrate and subsequently dried. When the coating suitability is poor, the dry coating surface becomes rough, the transparency is lowered, or the film forming property itself is not obtained, and the film scraps are formed without forming the coating layer. .

    The polylactic acid segment and the sulfonic acid metal base-containing segment in the copolymer polyurethane resin of the present invention can be obtained, for example, by a polyaddition reaction of a polylactic acid-containing diol, a sulfonic acid metal base-containing diol, and a diisocyanate. Furthermore, it is possible to carry out a polyaddition reaction in the presence of different diol components, and various functions can be added by selecting the diol component to be used.

The sulfonic acid metal base-containing segment copolymerized with the copolymer polyurethane resin of the present invention is a polyester diol having a chemical structure obtained by a condensation reaction between a dibasic acid having a sulfonic acid metal base or a diester compound thereof and a glycol component. A compound is preferred. The dibasic acid having a sulfonic acid metal base may be at least one selected from 5-sodium sulfoisophthalic acid, 3-sodium sulfoterephthalic acid, and 4-potassium sulfo-1,8-naphthalenedicarboxylic anhydride. preferable. Examples of the sulfonic acid metal base include sodium salts, lithium salts, and potassium salts. Among these, 5-sodium sulfoisophthalic acid is particularly preferable in view of solubility in a general-purpose solvent of a sulfonic acid metal base-containing segment obtained by copolymerization with general-purpose. Examples of the glycol component include ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,2-butylene glycol, 1,3-butylene glycol, 2,3-butylene glycol, 1,4- Butylene glycol, 2-methyl-1,3-propylene glycol, neopentyl glycol, 3-methyl-1,5-pentanediol, 2,2,4-trimethyl-1,3-pentanediol, 2,4-diethyl- 1,5-pentanediol, 2-ethyl-1,3-hexanediol, 2,2-dimethyl-3-hydroxypropyl-2 ′, 2′-dimethyl-3′-hydroxypropanoate, 2-n-butyl- 2-ethyl-1,3-propanediol, 3-ethyl-1,5-pentanediol, 3-propyl-1,5- Aliphatic diols such as ntanediol, 2,2-diethyl-1,3-propanediol, 3-octyl-1,5-pentanediol, 1,3-bis (hydroxymethyl) cyclohexane, 1,4-bis ( Hydroxymethyl) cyclohexane, 1,4-bis (hydroxyethyl) cyclohexane, 1,4-bis (hydroxypropyl) cyclohexane, 1,4-bis (hydroxymethoxy) cyclohexane, 1,4-bis (hydroxyethoxy) cyclohexane, 2 , 2-bis (4-hydroxymethoxycyclohexyl) propane, 2,2-bis (4-hydroxyethoxycyclohexyl) propane, bis (4-hydroxycyclohexyl) methane, 2,2-bis (4-hydroxycyclohexyl) propane, 3, (4), 8 (9) -Trichic [5.2.1.0 ^2,6] 1 selected from de alicyclic glycols Kanji such as methanol or aromatic glycols such as ethylene oxide or propylene oxide adduct to both terminal hydroxyl groups of bisphenol A It is preferable that it is a seed or more. Among these glycol components, 2,2,4-trimethyl-1,3-pentanediol, 2,4-diethyl-diethyl diol compound from the viewpoint of solubility of the obtained sulfonic acid metal base-containing polyester diol compound in a general-purpose solvent. 1,5-pentanediol, 2-ethyl-1,3-hexanediol, 2,2-dimethyl-3-hydroxypropyl-2 ′, 2′-dimethyl-3′-hydroxypropanoate, 2,2-bis ( 4-Hydroxycyclohexyl) propane, 3 (4), 8 (9) -tricyclo [5.2.1.0 ^2,6 ] decanedimethanol is preferred. More preferably, 2,2-dimethyl-3-hydroxypropyl-2 ′, 2′-dimethyl-3′-hydroxypropanoate, 2,2-bis (4-hydroxycyclohexyl) propane, 3 (4), 8 (9 ) -Tricyclo [5.2.1.0 ^2,6 ] decandimethanol, most preferably 2,2-dimethyl-3-hydroxypropyl-2 ′, 2′-dimethyl-3′-hydroxypropanate.

    In the sulfonic acid metal base-containing segment, a dibasic acid having a sulfonic acid metal base or a dibasic acid other than the diester compound and a diester compound thereof are in a range of less than 90 mol% when the total acid content is 100 mol%. It is possible to improve the solvent solubility of the sulfonic acid metal base-containing segment by copolymerization. Specific dibasic acid components include aromatic dibasic acids such as naphthalenedicarboxylic acid, terephthalic acid, isophthalic acid, and orthophthalic acid, and fats such as oxalic acid, glutaric acid, adipic acid, azelaic acid, sebacic acid, and dodecanoic acid. Alicyclic dibasic acids or alicyclic dibasic acids such as 1,2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, and diester compounds thereof.

    The number average molecular weight of the sulfonic acid metal base-containing segment is preferably 200 to 2000, more preferably 250 to 1500, and still more preferably 300 to 1100. If the number average molecular weight is too low, the polarity of the sulfonate group-containing segment will be too high, the compatibility with other raw materials will be poor, and a uniform reaction will be difficult to occur, or a hydroxyl group will be added to the molecular end of the sulfonate group-containing segment. There is a tendency that the component which does not have increases and copolymerizability worsens. On the other hand, if the number average molecular weight is too high, the copolymerization ratio of the sulfonic acid metal base-containing segment in the copolymerized polyurethane resin is increased, and the copolymerization ratio of the polylactic acid diol component is lowered.

    The polylactic acid segment copolymerized with the copolymer polyurethane resin of the present invention is preferably a polyester diol having a chemical structure that can be obtained by ring-opening addition of lactide using a polyol as an initiator. The polyol is preferably a diol, more preferably an aliphatic diol.

    The molar ratio (L / D) of L-lactic acid and D-lactic acid in the polylactic acid segment of the present invention is preferably 1 to 9, and within this range, good solubility in the reaction solvent during polyurethane polymerization and Urethane reactivity is obtained. When the molar ratio (L / D) of L-lactic acid and D-lactic acid is out of the above range, the solubility of the polylactic acid segment in a general-purpose solvent is deteriorated and the copolymerization reactivity is lowered.

    In the polylactic acid segment of the present invention, it is preferable to increase the content of lactic acid residues from the viewpoint of increasing the degree of biomass. Specifically, the total weight fraction of L-lactic acid residues and D-lactic acid residues in the polylactic acid segment is preferably 50% by weight or more, more preferably 70% by weight or more, and 90% by weight. % Or more is more preferable.

Examples of the method for synthesizing the polylactic acid segment of the present invention include the following two methods.
<First Synthesis Method> A method in which a lactide monomer is subjected to ring-opening addition polymerization using a diol containing no sulfonic acid metal base as an initiator.
<Second Synthesis Method> A method in which a lactide monomer is subjected to ring-opening addition polymerization using a diol containing a sulfonic acid metal base as an initiator.

  As the initiator used in the <first synthesis method>, various glycols exemplified as the constituent components of the sulfonic acid metal base-containing segment can be used. Among these, the use of glycols having a relatively low molecular weight such as ethylene glycol, 2-methylpentanediol, neopentyl glycol, etc. is preferable because the degree of biomass can be kept relatively high. In this case, the copolymer polyurethane resin of the present invention can be obtained by urethane copolymerization of the obtained polylactic acid diol containing no sulfonic acid metal base and the sulfonic acid metal base-containing segment.

    The initiator used in the <second synthesis method> contains a sulfonate metal base such as the sulfonate metal base-containing segment and / or a 2-fold mole of ethylene glycol condensation adduct to 5-sodium sulfoisophthalic acid. Diols can be used. In this case, since the obtained polylactic acid segment contains a sulfonic acid metal base, it is also a sulfonic acid metal base-containing segment, and the copolymer polyurethane resin of the present invention can be obtained by urethane copolymerization.

    In addition, the polylactic acid segment containing the sulfonic acid metal base obtained by the above <second synthesis method> and the polylactic acid segment not containing the sulfonic acid metal base obtained by the above <first synthesis method> The copolymer polyurethane resin of the present invention can also be obtained by polymerization. Further, urethane copolymerization of the polylactic acid segment containing the sulfonic acid metal base obtained in the above <second synthesis method> and the sulfonic acid metal base-containing segment not containing the polylactic acid component, Polylactic acid segment containing sulfonic acid metal base obtained by synthesis method>, polylactic acid segment not containing sulfonic acid metal base obtained by <First Synthesis Method>, and sulfonic acid metal containing no polylactic acid component The copolymer polyurethane resin of the present invention can also be obtained by urethane copolymerizing the base-containing segment. These methods are excellent in that the concentration of the sulfonic acid metal base in the copolymer polyurethane resin can be easily controlled.

    The number average molecular weight of the polylactic acid segment is preferably 400 to 10000, more preferably 800 to 5000, and still more preferably 1000 to 3000. If the number average molecular weight is less than 400, the amount of lactide monomer to be ring-opening added to the initiator is small, and the degree of biomass of the resulting copolymer polyurethane resin cannot be increased. On the other hand, when the number average molecular weight exceeds 10,000, the number of hydroxyl groups at the molecular end is small, so the reactivity of polylactic acid diol is lowered, and the high molecular weight reaction by urethane copolymerization is difficult to proceed.

    In a preferred embodiment of the present invention, suitability for coating on a film or the like can be improved by copolymerizing a polyether segment with a copolymer polyurethane resin. Specific examples of the polyether compound include polyethylene glycol, polypropylene glycol, polytetramethylene glycol, and the like. Among these, polyethylene glycol is most preferable from the viewpoint of improving coating suitability. The copolymerization rate in the copolymer polyurethane resin of the present invention is preferably 5% by weight to 20% by weight. If it is less than 5% by weight, the effect of improving the suitability for coating on a film or the like is not so much expressed. If it exceeds 20% by weight, the glass transition temperature of the copolymer polyurethane resin is lowered, and when used as a coating agent for a film, blocking resistance is prevented. The characteristics tend to decrease, which is not preferable. The number average molecular weight of the polyether segment chain to be copolymerized is preferably 200 to 6000, more preferably 400 to 2000, and still more preferably 400 to 1000 from the effect of enhancing the copolymerization reactivity and coating suitability. is there.

    When the polyether segment is copolymerized with the copolymer polyurethane resin of the present invention, it is also a preferred embodiment to use polypropylene glycol and / or polytetramethylene glycol as the polyether compound. In these embodiments, a coating film having excellent water resistance tends to be obtained.

    Examples of the diisocyanate compound (D) used in the copolymer polyurethane resin of the present invention include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, p-phenylene diisocyanate, 4,4′-diphenylmethane diisocyanate, m. -Phenylene diisocyanate, 3,3'-dimethoxy-4,4'-biphenylene diisocyanate, 2,6-naphthalene diisocyanate, 3,3'-dimethyl-4,4'-biphenylene diisocyanate, 4,4'-diphenylene diisocyanate, Aromatic diisocyanates such as 4,4′-diisocyanate diphenyl ether, 1,5-naphthalene diisocyanate, m-xylene diisocyanate, or hexamethylene diisocyanate, isophorone diisocyanate, , 4′-diphenylmethane diisocyanate and m-xylene diisocyanate hydrogenated and the like, and aliphatic and alicyclic diisocyanates. Among these, 2,4-tolylene diisocyanate, 4,4′-diphenylmethane diisocyanate, Hexamethylene diisocyanate is preferable from the viewpoint of versatility.

    By replacing a part of the diisocyanate compound used in the copolymer polyurethane resin of the present invention with a polyisocyanate having a functionality of 3 or more, the molecular weight of the copolymer polyurethane resin can be easily increased, and the reactivity with the curing agent is improved. It is possible to make it. However, if the substitution ratio of the trifunctional polyisocyanate is too low, these effects cannot be exhibited, and if the substitution ratio is too high, gelation of the copolymer polyurethane resin occurs, so the substitution ratio to the trifunctional or higher polyisocyanate is 0. It is preferably from 1 mol% to 5 mol%, more preferably from 0.5 mol% to 3 mol%. Preferable trifunctional or higher polyisocyanates include 3 molecules of tolylene diisocyanate or an adduct of 3 molecules of 1,6-hexane diisocyanate with respect to each molecule of trimethylolpropane or glycerin, and further, The compound which has an isocyanurate ring formed with hexane diisocyanate can be mentioned.

    In some cases, the toughness of the coating film can be improved by copolymerizing a diol compound, an aminoalcohol compound, or a diamine compound with the copolymer polyurethane resin of the present invention. Examples of the diol compound include various glycols exemplified as the constituent components of the sulfonic acid metal base-containing segment. Relatively low molecular weight compounds such as ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 2-methylpropylene glycol, neopentyl glycol, N-methylmonoethanolamine, and ethylenediamine have a relatively high biomass degree. It can be kept high, which is preferable.

    In addition, the copolymer polyurethane resin of the present invention is copolymerized with a polyol compound such as trimethanolpropane, triethanolamine, pentaerythritol and the like within a range in which the obtained copolymer polyurethane resin does not gel, thereby obtaining a molecular weight of the copolymer polyurethane resin. It is possible to improve the reactivity with the curing agent. Among these polyols, trimethylolpropane having a low molecular weight is preferable because the degree of biomass can be kept relatively high. The copolymerization ratio of the polyol compound is the sum of the polylactic acid diol (A), the sulfonic acid metal base-containing diol (B), and the diol (C) other than (A) (B) constituting the copolymer polyurethane resin of the present invention. On the other hand, it is preferably from 0.1 mol% to 5 mol%, more preferably from 0.5 mol% to 3 mol%.

    The average particle diameter of the water-based emulsion particles formed by the copolymer polyurethane resin of the present invention is preferably 200 nm or less. When the average particle diameter exceeds 200 nm, the storage stability of the emulsion liquid is poor, and the resin is likely to precipitate during storage. Also, the coating suitability is lowered, and a transparent and smooth coat layer is hardly formed.

    The number average molecular weight of the copolymer polyurethane resin of the present invention is preferably 5000 or more and less than 40000. More preferably, it is 8000 or more and less than 30000, More preferably, it is 10,000 or more and less than 25000. If it is less than 5000, the sulfonic acid metal base concentration in one molecule is low, and stable emulsion particles cannot be formed. Moreover, the coating film obtained by coating becomes brittle. On the other hand, when it exceeds 40,000, the coating suitability of the emulsion is lowered and it becomes difficult to form a smooth coat layer.

<Method for producing sustained-release biodegradable coating>
Although the manufacturing method of the sustained release biodegradable coating of the present invention is not particularly limited, it is preferably manufactured via the aqueous dispersion of the copolymer polyurethane resin of the present invention. The component to be coated is dissolved or dispersed in an aqueous dispersion, and then the aqueous dispersion itself is sprayed to evaporate the water to form particles, or sprayed in the presence of some carrier to adhere to the carrier surface and / or the inside of the carrier. This is because a biodegradable coating can be easily obtained by applying to some adherend and forming a coating film, which is convenient. Moreover, if the polylactic acid-based biodegradable resin is a self-emulsifying agent that can form an aqueous dispersion without the addition of a surfactant, the surfactant is released into the environment during the biodegradation process. This is more preferable because the environmental load is less. Further, if the aqueous dispersion does not contain an organic solvent or uses a small amount of the organic solvent, the organic solvent will not be released into the environment in both the manufacturing process of the covering and the use of the covering, or Less, more less environmental impact, more preferable.

    The aqueous dispersion of the copolymer polyurethane resin of the present invention is obtained, for example, by first polymerizing the copolymer polyurethane resin in a methyl ethyl ketone (hereinafter sometimes abbreviated as MEK) solution in the first stage and then in the second stage. The method can be prepared by mixing water in the MEK solution of the resin and then distilling off MEK from the system, but is not limited to this method.

    The copolymer polyurethane resin of the present invention can be stably stored as a dispersion liquid in which polymer particles are dispersed in 100% water and can be applied to a substrate. However, as a co-solvent, lower monomonomers such as methanol, ethanol, n-propanol, and isopropanol are used. Alcohols, or acetates such as ethyl acetate and butyl acetate, and amide solvents such as dimethylformamide and dimethylacetamide may be blended at an arbitrary concentration to further improve the coating suitability for a specific substrate.

    Hereinafter, the present invention will be described in more detail with reference to examples. These are all included in the technical scope of the present invention. In the following examples and comparative examples, unless otherwise specified, parts represent parts by weight.

The measurement and evaluation methods employed in this specification are as follows.
(1) Number average molecular weight A water permeation gel permeation chromatograph (GPC) 150C was used, tetrahydrofuran was used as a carrier solvent, and a differential refractometer (RI) detector was used and measured at a flow rate of 1 ml / min. Three columns, Shodex KF-802, KF-804, and KF-806, manufactured by Showa Denko K.K., were connected as columns, and the column temperature was set to 30 ° C. A polystyrene standard was used as the molecular weight standard sample.

(2) Acid value of sulfonate group-containing diol oligomer 0.2 g of 80% toluene solution was dissolved in 20 ml of tetrahydrofuran, and then measured with phenolphthalein as an indicator in a 0.1 N NaOH ethanol solution. The measured value was shown by the equivalent in 10 ⁶ g of resin solid content.

(3) Acid value of polylactic acid oligomer 0.5 g of the resin was dissolved in 20 ml of a mixed solution of chloroform / methanol = 3/1, and phenolphthalein was measured with 0.1N sodium methoxide methanol solution as an indicator. The measured value was shown by the equivalent in 10 ⁶ g of resin solid content.

(4) Glass transition temperature 5 mg of a sample was put in an aluminum sample pan and sealed, and the temperature was increased to 200 ° C. at a rate of temperature increase of 20 ° C./min using a differential scanning calorimeter DSC-220 manufactured by Seiko Instruments Inc. Measured and determined at the temperature of the intersection of the baseline extension below the glass transition temperature and the tangent indicating the maximum slope at the transition.

(5) Polymer composition A resin was dissolved in chloroform-d, and a resin composition ratio was determined by ¹ H-NMR using a nuclear magnetic resonance analyzer (NMR) “Gemini-200” manufactured by Varian.

(6) Average particle diameter of emulsion particles The arithmetic average diameter based on volume particle diameter was measured using HORIBA LB-500 and adopted as the average particle diameter of emulsion particles.

Hereinafter, the abbreviations of the compounds shown in the text and tables in the examples indicate the following compounds, respectively.
NPG: Neopentyl glycol TMP: Trimethylolpropane MDI: 4,4′-diphenylmethane diisocyanate HDI: Hexamethylene diisocyanate PEG # 1000: Polyethylene glycol, number average molecular weight 1000
MEK: Methyl ethyl ketone IPA: Isopropyl alcohol

Production example of polylactic acid diol N1 As a catalyst, L-lactide 900 parts, D-lactide 100 parts, neopentyl glycol 55 parts in a 2 L glass four-necked flask equipped with a stir bar, thermometer and Liebig condenser 0.14 parts of tin octylate was charged, dried in a dry nitrogen gas stream at room temperature for 30 minutes, and further dried under reduced pressure for 30 minutes, and the flask was heated to 180 ° C. After reacting for 3 hours with uniform stirring at 180 ° C., the system was depressurized at the same temperature, and unreacted monomers were distilled off. The decompression was completed in 30 minutes, and the contents were poured out into a release heat-resistant bat. The resulting polylactic acid diol N1 had an acid value of 12 equivalents / ton and a number average molecular weight of 2300.

Production Example of Sulfonate Group-Containing Polyester Diol S1 291 parts of 5-sodium sulfoisophthalic acid and 918 parts of 2,2-dimethyl are added to a 2-liter glass four-necked flask equipped with a stir bar, thermometer and Liebig condenser. -3-Hydroxypropyl-2 ′, 2′-dimethyl-3′-hydroxypropanoate, 0.16 parts of tetrabutyl titanate as a catalyst and 15 parts of triethylamine as a stabilizer were added, and the temperature was raised to 180 ° C. The reaction temperature was gradually raised while distilling off the generated methanol, and the temperature was raised to 230 ° C. in 3 hours. After confirming the completion of the distillation of methanol, the reaction temperature was further raised to 250 ° C. After the temperature reached 250 ° C., the system was decompressed for 10 minutes to complete the reaction. When the obtained reaction product was cooled to 100 ° C. or less under a dry nitrogen gas stream, it was diluted with toluene so that the concentration of the produced polymer component was 80% by weight, and uniformly stirred and dissolved. After cooling, moisture absorption was avoided and the product was stored in a sealed container.

Production Example of Copolymer Polyurethane Resin P1 In a 1 L glass four-necked flask equipped with a stirrer, a thermometer, and a condenser, 100 parts of polylactic acid diol N1, 32.5 parts of sulfonate group-containing polyester diol S1 and 100 parts of MEK was charged and dissolved uniformly. It was then heated to 50 ° C. and 40 parts of 4,4′-diphenylmethane diisocyanate (MDI) was added. After further reaction at 70 ° C. for 30 minutes, 19 parts of polyethylene glycol (PEG # 1000) was added. After 30 minutes, 0.04 parts of dibutyltin dilaurate was added as a catalyst, reacted at 70 ° C. for a further 2 hours, diluted with 184 parts of MEK, and then 4 parts of trimethylolpropane were added. After 2 hours, 152 parts of MEK was added to dilute to a solid content concentration of 30% by weight to complete the reaction. The number average molecular weight of the obtained copolymer polyurethane resin P1 was 23700.

Example 1
A 2 L glass four-necked flask equipped with a stir bar, thermometer, and Liebig condenser was charged with 500 parts of a 30 wt% MEK solution of copolymer polyurethane resin P1 and 90 parts of isopropyl alcohol (IPA), and stirred at 40 ° C. to dissolve. did. Next, 300 parts of deionized water was gradually poured and stirred at 40 ° C. until the system was uniform. The system was then depressurized while maintaining the temperature at 40 ° C., and a total of 460 parts of MEK, IPA and water were distilled off. The obtained aqueous dispersion E1 had a solid content concentration of 35% by weight, an average particle diameter of 71 nm, a number average molecular weight of 20,600, and a glass transition temperature (Tg) of 44 ° C. Next, a nitrogen-based granular fertilizer component having an average particle diameter of 4 mm is spray-coated with a water dispersion E1 using a jet coating apparatus, and moisture is evaporated and dried with hot hot air to form a coated granular sustained-release biodegradable coating body H1 was obtained.
An aqueous dispersion E1 is spray-coated on a nitrogen-based granular fertilizer component having an average particle diameter of 4 mm using a jet coating apparatus, and moisture is evaporated and dried with hot hot air to form a coated granular sustained-release biodegradable coating H1. Obtained.
The aqueous dispersion E1 was coated on a polypropylene film, dried in a hot air dryer at 60 ° C., and then peeled off from the polypropylene sheet to prepare a sheet made of a copolymer polyurethane resin P1 having a dry thickness of about 20 μm. Using this sheet, biodegradability in an aerobic dark place was evaluated. The specific evaluation method was based on ASTM-D5338. The evaluation results are shown in Table 1. The decomposition rate of this sheet was faster than that of a sheet made of copolymer polyurethane resin P2 described later, but was found to be slower than that of cellulose. The copolymer polyurethane resin P1 is suitable for a coating material and a coated body that exhibit a sustained release property and wants to finish the release of the component to be coated in a relatively short period of time.

Production example of polylactic acid diol N2 In the same manner as polylactic acid diol N1, except that the amount of neopentyl glycol charged was changed to 36 parts to obtain polylactic acid diol N2. The acid value of N2 was 14 equivalents / ton, and the number average molecular weight was 3400.

Production Example of Copolymer Polyurethane Resin P2 A glass four-necked flask equipped with a stirrer, a thermometer, and a condenser was charged with 50 parts of polycalolactone diol (PCL), 21 parts of sulfonate group-containing polyester diol S1 and 100 parts of MEK was charged and dissolved uniformly. It was then heated to 50 ° C. and 22 parts of hexamethylene diisocyanate (HDI) was added. After a further 30 minutes of reaction at 70 ° C., 100 parts of polylactic diol N2 was added. After 30 minutes, 0.04 part of dibutyltin dilaurate was added as a catalyst, reacted at 70 ° C. for another 2 hours, diluted with 194 parts of MEK, and 3 parts of trimethylolpropane was added. Two hours later, 158 parts of MEK was added to dilute to a solid concentration of 30% by weight to complete the reaction. The number average molecular weight of the obtained copolymer polyurethane resin P2 was 23900.

Example 2
A 2 L glass four-necked flask equipped with a stir bar, thermometer, and Liebig condenser was charged with 500 parts of a 30 wt% MEK solution of copolymer polyurethane resin P2 and 90 parts of isopropyl alcohol (IPA) and uniformly dissolved at 40 ° C. . Next, 300 parts of deionized water was gradually poured and stirred at 40 ° C. until the system was uniform. The system was then depressurized while maintaining the temperature at 40 ° C., and a total of 470 parts of MEK, IPA and water were distilled off. The obtained aqueous dispersion E2 had a solid content concentration of 36% by weight, an average particle size of 108 nm, a number average molecular weight of 22500, and a glass transition temperature (Tg) of 0 ° C.
A nitrogen-based granular fertilizer component having an average particle size of 4 mm is spray-coated with a water dispersion E2 using a jet coating apparatus, and moisture is evaporated and dried with hot hot air to form a coated granular sustained-release biodegradable coating H2. Obtained.
The aqueous dispersion E2 was coated on a polypropylene film, dried in a hot air dryer at 60 ° C., and then peeled off from the polypropylene sheet to prepare a sheet made of copolymer polyurethane P2 having a dry thickness of about 20 μm. Using this sheet, biodegradability in an aerobic dark place was evaluated. The specific evaluation method was based on ASTM-D5338. The evaluation results are shown in Table 1. The biodegradation rate of this sheet is relatively slow and is suitable for coatings and coatings where release of the coated component over a relatively long period is required.

Production Example of Copolymer Polyurethane Resin P3 100 parts of polylactic acid diol N1 and 100 parts of MEK were charged and uniformly dissolved in a 1 L glass four-necked flask equipped with a stirrer, a thermometer, and a condenser. Then, 23 parts of 4,4′-diphenylmethane diisocyanate (MDI) was added at 50 ° C. and reacted at 70 ° C. for 30 minutes, and then 20 parts of polyethylene glycol (PEG # 1000) was added. After 30 minutes, 0.02 part of dibutyltin dilaurate was added as a catalyst, reacted at 70 ° C. for another 2 hours, diluted with 122 parts of MEK, and then 4 parts of trimethylolpropane were added. After 2 hours, 124 parts of MEK was added to dilute to a solid concentration of 30% by weight to complete the reaction. The number average molecular weight of the obtained copolymer polyurethane resin P3 was 24200.

Production Example of Copolymer Polyurethane Resin P4 75 parts of polycalolactone diol (PCL) and 50 parts of MEK were charged in a glass four-necked flask equipped with a stirrer, a thermometer, and a condenser, and dissolved uniformly. Next, 20 parts of hexamethylene diisocyanate (HDI) was added at 50 ° C. and reacted at 70 ° C. for 30 minutes, and then 100 parts of MEK and 100 parts of polylactic acid diol N 2 were added. After 30 minutes, 0.05 parts of dibutyltin dilaurate was added as a catalyst, reacted at 70 ° C. for another 2 hours, diluted with 225 parts of MEK, and then 4.5 parts of trimethylolpropane was added. Two hours later, 208 parts of MEK was diluted to a solid concentration of 30% by weight to complete the reaction. The number average molecular weight of the obtained copolymer polyurethane resin P4 was 26300.

Comparative Examples 1 and 2
A 2 L glass four-necked flask equipped with a stir bar, thermometer, and Liebig condenser was charged with 500 parts of a 30 wt% MEK solution of copolymer polyurethane resins P3 and P4 and 90 parts of isopropyl alcohol (IPA) and dissolved at 40 ° C. did. Next, 300 parts of deionized water was gradually poured and stirred at 40 ° C., but the system was not uniform and an aqueous dispersion could not be obtained.

    The sustained-release biodegradable covering in the present invention is gradually decomposed by organisms such as microorganisms in the natural environment such as the surface and the inside of soil, river lakes, and the ocean, etc. It exhibits the effect of continuously releasing over a long period. For this reason, by selecting an appropriate component to be coated, it can be used as a sustained-release agricultural chemical, a slow-release fertilizer, a bioadhesive coating agent, and the like.

Claims (13)

  A sustained-release biodegradable coating agent comprising a copolymer polyurethane resin having a polylactic acid segment and a sulfonate group-containing segment in the molecule.   The sustained-release biodegradable coating agent according to claim 1, wherein the sulfonate group-containing segment comprises a copolymerized polyester.   The sustained-release biodegradable coating agent according to claim 1 or 2, wherein the sulfonate group is one or more of a sulfonate metal base, a sulfonate quaternary ammonium base, or a sulfonate quaternary sulfonium base. . Polylactic acid diol (A),
Sulfonate group-containing diol (B),
(A) Diol (C) other than (B),
Is a sustained-release biodegradable coating agent comprising a copolymerized polyurethane resin having a structure in which is bonded by a polyaddition reaction with a diisocyanate compound (D).   The sustained-release biodegradable coating agent according to any one of claims 1 to 4, wherein a concentration of the sulfonate group is 50 eq / ton or more and 500 eq / ton or less.   The sustained-release biodegradable coating agent according to claim 4, wherein the diol (C) contains 2,2-dimethyl-3-hydroxypropyl-2 ', 2'-dimethyl-3'-hydroxypropanate.   The sustained-release biodegradable coating agent according to claim 4, wherein the diol (C) contains a polyether diol.   The sustained-release biodegradable coating according to claim 4, wherein 0.1 mol% or more and 5 mol% or less of the total of the diols (A), (B), and (C) is substituted with a trifunctional or more functional polyol. Agent.   The sustained-release biodegradable coating agent according to claim 4, wherein 0.1 mol% or more and 5 mol% or less of the diisocyanate compound (D) is substituted with a trifunctional or higher polyisocyanate.   The molar ratio (L / D) of L-lactic acid and D-lactic acid constituting the diol (A) is 1 to 9, and the total weight of the L-lactic acid residue and the D-lactic acid residue with respect to the diol (A) The sustained-release biodegradable coating agent according to claim 4, wherein the fraction is 50% by weight or more.   The sustained-release biodegradable coating body which coat | covered the to-be-coated component with the biodegradable coating agent in any one of Claims 1-10.   The sustained-release biodegradable covering according to claim 11, wherein the component to be coated has one or more functions of insecticidal, herbicidal, sterilizing, antifungal, biological attraction and biological repellent. The sustained-release biodegradable coating according to claim 11, wherein the component to be coated has one or more functions of physiological activity, growth promotion, and nutritional supplementation for living organisms.