JP2006089613A - Dimethylolalkanoic acid solution - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a dimethylolalkanoic acid solution effective for facilitating the handling of a dimethylolalkanoic acid and improving the compatibility and reactivity with a resin and safe to human body, a method for producing a water-based urethane resin proceeding uniform urethanization reaction, an adhesion promoter to increase the adhesiveness of a coating agent to various substrates and a coating agent compounded with the adhesiveness promoter. <P>SOLUTION: The invention provides a dimethylolalkanoic acid solution produced by dissolving a dimethylolalkanoic acid in an alcohol compound having a molecular weight of ≤400, a method for producing a water-based urethane resin by reacting the dimethylolalkanoic acid solution with an organic polyisocyanate and a polyol, a water-based urethane resin produced by the method, an adhesiveness promoter composed of the dimethylolalkanoic acid solution, and a coating agent compounded with the adhesiveness promoter. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a dimethylol alkanoic acid solution, and more specifically, a dimethylol alkanoic acid solution obtained by dissolving dimethylol alkanoic acid in a specific alcohol compound, a method for producing an aqueous urethane resin using a dimethylol alkanoic acid solution, and aqueous The present invention relates to a urethane resin, an adhesion imparting agent, and a coating agent. The dimethylol alkanoic acid solution of the present invention is useful as a modifier for urethane resin raw materials, coating agents such as adhesion imparting agents, aqueous resin raw materials, polyester resin raw materials, and epoxy resins.

  Dimethylol alkanoic acid is widely used mainly as an aqueous material such as aqueous urethane resin. In this case, dimethylol alkanoic acid is usually used as a solid powder, charged separately from other raw materials in a reaction apparatus, and reacted with an organic polyisocyanate to produce an aqueous urethane resin. However, in this method, since dimethylol alkanoic acid is a solid powder, when it is charged into the reactor, the powder moves into the reactor and adheres to the surroundings, or the powder solidifies and dissolves into large lumps. There is a problem that the urethanization reaction is difficult to proceed uniformly. Therefore, it is known to use a high-boiling polar organic solvent such as N-methylpyrrolidone or dimethylformamide in order to make the dimethylolalkanoic acid raw material liquid (see Patent Document 1).

  On the other hand, a laminate between plastic films such as polyethylene, polypropylene, nylon, polyethylene terephthalate, etc., a multilayer structure of a plastic film and a metal foil such as aluminum or a metal vapor-deposited film of plastic, a coated plate provided with a coating layer on a metal substrate, An adhesive made of polyurethane resin, polyester resin, epoxy resin or the like is used for forming a metal can or the like.

As the above-mentioned adhesive, a two-part curable adhesive comprising a polyol having a carboxyl group in the molecular chain through an ester bond and a polyisocyanate curing agent (see Patent Document 2), a polyol and a number average molecular weight of 200 to 5000 are specified A two-component adhesive for dry lamination comprising a dihydroxycarboxylic acid and a polyisocyanate curing agent (see Patent Document 3), a polybasic acid anhydride such as a polyol and pyromellitic acid anhydride, and a polyisocyanate curing agent A composite laminating adhesive (see Patent Document 4) is described.
Japanese Patent Publication No. 4-488 JP-A-3-281589 Japanese Patent Laid-Open No. 8-183943 JP 61-47775 A

  However, the use of a polar organic solvent such as N-methylpyrrolidone or dimethylformamide to make the dimethylolalkanoic acid raw material liquid is not preferable for human health. Further, when it is not desired to leave a solvent in the reaction product, it is difficult to remove the solvent from the reaction product. On the other hand, the above-mentioned adhesive has problems that the compounding conditions of each component are severe or that excellent adhesiveness cannot be obtained unless it is processed at a high temperature. Moreover, it cannot be said that sufficient adhesiveness is exhibited depending on the kind of base material, and its intended use is limited and versatility is poor.

  The present invention has been made in view of such circumstances, and its purpose is to facilitate handling of dimethylolalkanoic acid, to improve compatibility with resins, reactivity, and the like, and to be safe for the human body. A dimethylolalkanoic acid solution is provided.

  Another object of the present invention is to provide a method for producing an aqueous urethane resin in which the urethanization reaction proceeds uniformly and an aqueous urethane resin obtained by the method.

  Another object of the present invention is to provide an adhesion-imparting agent that enhances the adhesion of the coating agent to various substrates and a coating agent containing the same.

  As a result of intensive studies, the inventors of the present invention can easily handle dimethylol alkanoic acid by using a specific low molecular weight alcohol compound as a solvent for dissolving dimethylol alkanoic acid. Improves compatibility, reactivity, etc., and can safely work on the human body, and the obtained dimethylolalkanoic acid solution is a highly concentrated and stable solution state of urethane resin raw materials and adhesion-imparting agents As a result, the present invention has been completed. And this invention consists of a group of related invention, and the summary of each invention is as follows.

  A first gist of the present invention is a dimethylol alkanoic acid solution obtained by dissolving dimethylol alkanoic acid in a solvent, wherein the solvent is an alcohol compound having a molecular weight of 400 or less. Exist.

    The second gist of the present invention resides in a method for producing an aqueous urethane resin characterized by reacting the dimethylolalkanoic acid solution, the organic polyisocyanate and the polyol according to the first gist.

  The third gist of the present invention resides in an aqueous urethane resin produced by the production method of the second gist.

  The fourth gist lies in an adhesion-imparting agent comprising the dimethylol alkanoic acid solution of the first gist.

  The subject matter of the fifth invention resides in a coating agent comprising the adhesion imparting agent of the fourth subject matter described above.

  According to the present invention, the dimethylolalkanoic acid solution is easy to handle and blend, and in the production of an aqueous urethane resin, the urethanization reaction proceeds uniformly and can be safely performed on the human body. Further, the dimethylol alkanoic acid solution of the present invention is an organic solvent-type or solvent-free type urethane resin or polyester resin raw material, aqueous urethane resin, aqueous polyester resin, aqueous resin raw material such as electrodeposition paint, coating agent, etc. It can be used in a wide range of applications such as modifiers such as adhesion promoters, modifiers such as epoxy resins, powder coating materials, and antibacterial agents.

  Hereinafter, the present invention will be described in detail. The constituent elements described below are examples (representative examples) of the embodiments of the present invention, and are not specified in these contents.

  Examples of dimethylolalkanoic acid include dimethylolpropionic acid, dimethylolbutanoic acid, dimethylolpentanoic acid, dimethylolheptanoic acid, dimethyloloctanoic acid, dimethylolnonanoic acid, and the like. Among these, dimethylolbutanoic acid is preferred from the viewpoints of solubility in alcohol compounds, reactivity with polyisocyanates, and availability of industrial products.

  Dimethylol butanoic acid is usually a powder, and the particle size is usually 1.0% by weight or less of particles of 1.0 mm or more and 95.0% by weight or more of particles of 800 μm or less from the viewpoint of solubility. Preferably, 1.0 mm or more of particles having a size of 1.0 mm or more and 95.0 wt% or more of particles having a size of 600 μm or less. From the viewpoint of the fluidity of the powder, the angle of repose is usually 20 ° to 80 °, preferably 35 ° to 70 °.

The method for producing dimethylolalkanoic acid is not particularly limited, and is produced by subjecting an aldehyde to an aldol condensation and an oxidation reaction. For example, the production of dimethylolbutanoic acid is carried out by known methods (Japanese Patent Laid-Open Nos. 52-124213, 11-1003009, and 2002-226426). At the time of storage, it is preferable to store in a container made of a material having a moisture permeability of 40 g and a temperature of 5 g / m ² · day or less from the viewpoint of preventing the powder from consolidating.

  The alcohol compound that dissolves dimethylolalkanoic acid is an alcohol compound having at least one hydroxyl group in the molecule. For example, methanol, ethanol, propanol, isopropanol, butanol, isobutyl alcohol, sec-butyl alcohol, tert-butyl alcohol, pentanol, isopentyl alcohol, 2-methyl-1-butanol, 3-methyl-2-butanol, 2- Monoalcohols such as methyl-1-pentanol, hexanol, heptol, octanol, 2-ethyl-1-hexanol, nonanol, decanol, diacetone alcohol, various cellosolves, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, Propylene glycol, dipropylene glycol, tripropylene glycol, 1,4-butanediol, 1,3-butanediol, 1,2-butanediol, 3-methylpentanediol , Glycols such as 1,5-pentanediol, 1,6-hexanediol, triols such as glycerin, 1,2,6-hexanetriol, trimethylolethane, trimethylolpropane, sugars such as erythritol, sorbitol, etc. Is mentioned. You may use these individually or in mixture of 2 or more types.

  The molecular weight of the alcohol compound is usually 30 to 400, preferably 60 to 200, as the number average molecular weight. When the molecular weight exceeds 400, the solubility of dimethylolalkanoic acid and the storage stability of the solution may be deteriorated.

  In use as a raw material for aqueous urethane resins, glycols are preferred among the above alcohol compounds in view of having an appropriate pot life, increasing the molecular weight, and reacting to be incorporated as a resin component. is there. For example, ethylene glycol (freezing point: −13 ° C., boiling point: 197.6 ° C.), diethylene glycol (freezing point: −8 ° C., boiling point: 244.3 ° C.), triethylene glycol (freezing point: −7.2 ° C., boiling point: 287) .4 ° C.), propylene glycol (freezing point: −60 or lower, boiling point: 187.4 ° C.), dipropylene glycol (freezing point: −40 ° C., boiling point: 231.8 ° C.), tripropylene glycol (freezing point: −20 ° C. or lower) , Boiling point: 268 ° C.), 1,4-butanediol (freezing point: 20.1 ° C., boiling point: 228 ° C.), 1,3-butanediol (freezing point: −50 or less, boiling point: 207.5 ° C.), 1, 2-butanediol (freezing point: -114 ° C, boiling point: 194 ° C), 1,5-pentanediol (freezing point: -15.6 ° C, boiling point: 242.4 ° C), 3-methylpentanediol (Freezing point: −50 ° C. or lower, boiling point: 250 ° C.) and glycerin (freezing point: 18.1 ° C., boiling point: 290 ° C.). Among these, ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, 1,4-butanediol, and 1,3-butanediol are preferable.

  In consideration of the storage stability of the dimethylolalkanoic acid solution, alcohol compounds having a freezing point of usually 70 ° C. or lower, preferably 30 ° C. or lower, more preferably 0 ° C. or lower are suitable. When the freezing point exceeds 70 ° C., the solubility of dimethylolalkanoic acid in an alcohol compound is lowered, and the stability of the solution may be deteriorated. The volatility of the alcohol compound is preferably low. As a boiling point of an alcohol compound, Preferably it is 60 degreeC or more, More preferably, it is 100 degreeC or more, More preferably, it is 150 degreeC or more.

  The dimethylolalkanoic acid solution of the present invention may contain a hydroxyalkanoic acid such as glycolic acid, lactic acid, malic acid or the like, if necessary. The dimethylol alkanoic acid in the dimethylol alkanoic acid solution of the present invention may be neutralized with a tertiary amine such as triethylamine or ethanolamine.

  The dimethylol alkanoic acid solution of the present invention is obtained by dissolving dimethylol alkanoic acid in an alcohol compound usually at 20 to 120 ° C. The lower limit of the content of dimethylolalkanoic acid relative to the total amount of the alcohol compound and dimethylolalkanoic acid is usually 5% by weight, preferably 10% by weight, and the upper limit is usually 80% by weight, preferably 70% by weight. %. When the content of dimethylol alkanoic acid is less than 5% by weight, the effect as an adhesion-imparting agent is insufficient, and when the content of dimethylol alkanoic acid exceeds 80% by weight, A methylolalkanoic acid solution may not be obtained.

  The dimethylol alkanoic acid solution in the present invention can be used for conventional dimethylol alkanoic acid applications, as well as good handleability due to being liquid, compatibility with resins and other raw materials, Utilizing good reactivity, it can be used for a wide range of applications. For example, ordinary urethane resin raw materials, modifiers such as coating agent adhesion-imparting agents, organic solvent- or solvent-free urethane resins and polyester resin raw materials, aqueous urethane resins and aqueous polyester resins, and aqueous resins such as electrodeposition paints It is useful for water-based raw materials, modifiers such as epoxy resins, powder coating materials, antibacterial agents, and emulsifying aids.

  Next, the use of the dimethylol alkanoic acid solution of the present invention as an adhesion promoter for aqueous urethane resin raw materials and coating agents will be described.

  The dimethylol alkanoic acid solution is a composition composed of dimethylol alkanoic acid and an alcohol compound, and is not a reactive substance per se, and is blended with an organic polyisocyanate and a polyol. It is a constituent component of urethane resin.

  The aqueous urethane resin is generally obtained by reacting (1) an organic polyisocyanate, polyol, dimethylolalkanoic acid and, if necessary, glycols as a chain extender in the presence or absence of an organic solvent, and the resulting isocyanate group terminal. A method in which a urethane prepolymer is neutralized and dispersed in water, and then the urethane prepolymer is chain-extended with a diamine or the like, and then, if necessary, a solvent removal treatment. (2) Organic polyisocyanate, polyol, dimethylolalkane The acid, glycols and, if necessary, triols are reacted in the presence of an organic solvent, the resulting high molecular weight polyurethane solution is neutralized with a tertiary amine, etc., dispersed by adding water, and then removed from the solvent. (3) organic polyisocyanate, polyol, dimethylolalkanoic acid and, if necessary, The acrylic monomer solution of the resulting isocyanate group-terminated urethane prepolymer is neutralized and dispersed in water, and the urethane prepolymer is chain-extended with a chain extender. Is produced by a radical polymerization method using a radical initiator.

  In the case of producing an aqueous urethane resin by the method using the chain extender of the above-described method, conventionally, dimethylolalkanoic acid and the chain extender were separately charged, but dimethylolalkanoic acid is a solid powder. Therefore, it is difficult to handle in the reaction apparatus at the time of preparation, and it may not completely dissolve during the reaction and may remain, adhere and aggregate in the reaction apparatus. However, since the dimethylol alkanoic acid solution of the present invention is a uniform liquid and can be used in a state in which dimethylol alkanoic acid is dissolved in advance, it is possible to obtain a high-quality aqueous urethane resin without causing the above-mentioned troubles. Is possible.

  The method for producing the aqueous urethane resin of the present invention is not particularly limited, and can be applied to any known method. For example, when a urethane prepolymer or a high molecular weight polyurethane is produced in the above production method, an alcohol compound solution of dimethylol alkanoic acid is supplied into the reactor instead of charging solid powdery dimethylol alkanoic acid. At that time, when glycols or the like are used as the alcohol compound, the glycols themselves react with the organic polyisocyanate to be finally incorporated into the resin molecular chain, and serve as a chain extender. Of course, glycols as chain extenders can be added as necessary, and chain extenders such as diamines can be used in combination with glycols.

  In the production of the aqueous urethane resin, the equivalent ratio of the NCO group of the organic polyisocyanate to the hydroxyl group of the polyol and dimethylolalkanoic acid solution in the production of the urethane prepolymer of the method (1) is NCO / OH = 1.1 / 1. A range of ˜30 / 1 is preferred. At that time, in order to reduce the viscosity of the prepolymer and facilitate the subsequent emulsification / dispersion operation, it is possible to adjust the concentration to an appropriate level using an organic solvent and react in the organic solvent as necessary. is there.

  As the organic solvent, an organic solvent having a boiling point of 50 to 120 ° C. is preferable so that it can be easily removed after the resin is made aqueous. For example, acetone (boiling point 56.3 ° C), methyl ethyl ketone (boiling point 79.6 ° C), methyl isobutyl ketone (boiling point 117 ° C), tetrahydrafuran (boiling point 66 ° C) 1,4-dioxane (boiling point 101.4 ° C), Examples include ethyl acetate (boiling point 76.8 ° C.) and toluene (boiling point 110.6 ° C.). Among these, considering the good solubility of the polyurethane resin and easy removal, acetone and methyl ethyl ketone are preferable, and acetone is particularly preferable.

  The urethanization reaction temperature is usually 20 to 120 ° C, preferably 40 to 100 ° C, and more preferably 50 to 95 ° C. When the reaction temperature is less than 40 ° C., the raw material has poor solubility and the reaction rate is slow. Moreover, when temperature exceeds 90 degreeC, reaction with a carboxyl group and an isocyanate group will occur easily, a gel-like thing may be produced in a prepolymer, or the whole may gelatinize. The reaction time is not generally determined depending on the reaction temperature, solid content, etc. in the reaction of each stage, but is usually about 1 to 40 hours. In addition, the urethanization reaction may be performed without a catalyst, but in order to accelerate the reaction, for example, an organometallic catalyst such as dibutyltin dilaurate, dibutyltin dioctoate, stannous octoate, a tertiary class such as triethylenediamine, triethylamine, tributylamine, etc. An amine catalyst can be used.

  In order to disperse the urethane prepolymer in water, it is necessary to neutralize the carboxyl group derived from dimethylolalkanoic acid and form an ionic group to impart self-emulsifying properties. Examples of the neutralizing agent to be used include tertiary amines such as triethylamine, monoethanolamine, diethanolamine, triethanolamine, triethylenediamine and dimethylaminoethanol, and alkali metal compounds such as sodium hydroxide and potassium hydroxide. The neutralization rate with respect to a carboxyl group is 50-50 mol% normally. The temperature of the urethane prepolymer for neutralization is preferably in the range of 20 to 60 ° C.

  As a method of dispersing the neutralized urethane prepolymer in water, a dispersion treatment with a normal stirrer can be mentioned. Examples of a method for obtaining a uniform aqueous dispersion having a finer particle diameter include dispersion treatment using a homomixer, a homogenizer, a disper, a line mixer, and the like. Addition of water is performed by methods such as batch preparation, divided preparation, dropping preparation, forced injection, etc., but considering the reaction between the terminal isocyanate group of the urethane prepolymer and water, the addition of water should be performed within 1 hour. preferable. A chain extender such as diamine, which will be described later, is added to the obtained aqueous dispersion of urethane prepolymer, and a chain extension reaction is usually performed at 20 to 50 ° C. to produce polyurethane. Examples of the method for removing the organic solvent used in the production of the urethane prepolymer from the system include a method of expelling with an air or nitrogen, a method of distilling off under reduced pressure and a method of evaporating a thin film.

  Organic polyisocyanates used for the production of aqueous urethane resins include aromatic (yellowing type) and aliphatic or alicyclic (non-yellowing type). For example, aromatic polyisocyanates include 2,4-tolylene diisocyanate and a mixture thereof with 2,6-tolylene diisocyanate (abbreviated as TDI), 4,4′-diphenylmethane diisocyanate (MDI), 1,4- Examples include phenylene diisocyanate and 1,5-naphthalene diisocyanate (NDI). Examples of the aliphatic polyisocyanate include hexamethylene diisocyanate (HMDI) and trimethylhexamethylene diisocyanate. Examples of the alicyclic polyisocyanate include isophorone diisocyanate (IPDI), cyclohexane-1,4-diisocyanate, 4, Examples thereof include 4'-dicyclohexylmethane diisocyanate (H12MDI), a hydrogenated product of TDI, and the like. Furthermore, xylylene diisocyanate (XDI), tetramethyl xylylene diisocyanate and the like can be mentioned. These can be used individually or in mixture of 2 or more types. If necessary, a small amount of a polyfunctional isocyanate which is a reaction product with a trimer such as TDI, HMDI, or IPDI, or trimethylolpropane may be used in combination.

  The polyol is not particularly limited as long as it has two or more hydroxyl groups in one molecule, and examples thereof include polyether polyol, polyester polyol, polycarbonate polyol, polybutadiene polyol, and hydrogenated polybutadiene polyol. . Specific examples of the polyether polyol include polyethylene glycol, polypropylene glycol, poly (ethylene / propylene) glycol, and polytetramethylene ether glycol. Polyester polyols include those obtained by polycondensation of a low molecular weight diol and a dibasic acid and those obtained by a ring-opening reaction using a low molecular weight diol as an initiator. Examples of the low molecular weight diol polycondensed with the former dibasic acid include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, 1,4-butanediol, 3-methyl-1,5-pentanediol, and 1,6-hexane. Examples of the dibasic acid include adipic acid, azelaic acid, sebacic acid, isophthalic acid, and terephthalic acid.

  Examples of the latter low molecular weight diol initiator include poly ε-caprolactone, poly β-methyl-δ-valerolactone, and the like. Examples of the polycarbonate polyol include 1,6-hexanediol polycarbonate polyol, 3-methyl-1,5-pentanediol polycarbonate polyol, and mixed diol polycarbonate polyol having 4 to 6 carbon atoms. Examples of the polybutadiene polyol include a polyol composed of 1,4-polybutadiene and 1,2-polybutadiene. Hydrogenated polybutadiene polyol is a hydrogenated polybutadiene polyol having a paraffin skeleton. Among these polyols, amorphous and liquid are more preferable from the viewpoint of ease of handling. Moreover, you may use together high molecular polyols and the said low molecular weight diol, or triols, such as a trimethylol propane and glycerol, as needed. The above polyols may be used alone or in combination of two or more.

  The average molecular weight of the polyol is usually 500 to 10,000, preferably 500 to 4,000. When the average molecular weight is less than 500, the function as a polyol is not exhibited, and when the average molecular weight exceeds 10,000, the viscosity of the obtained urethane prepolymer becomes high, and aggregates are generated or dispersed during water dispersion. May cause defects.

  Examples of the chain extender used for the chain extension of the urethane prepolymer in the above method (1) include diamines such as ethylenediamine, hexamethylenediamine, cyclohexanediamine, cyclohexylmethanediamine, and isophoronediamine, hydrazine, and dicarboxylic acid dihydrazide. And water. The amount of these chain extenders is preferably such that the equivalent ratio of urethane prepolymer to isocyanate groups is in the range of NCO / active hydrogen = 1 / 0.8 to 1 / 1.2.

  In the above method (2), when a high molecular weight polyurethane is produced in an organic solvent, after the urethane prepolymer is produced, a chain extender such as glycols or triols is added as necessary to increase the molecular weight. There is a method of performing a reaction, or a method of performing a high molecular weight reaction from the beginning by adding an organic polyisocyanate, a polyol, a dimethylolalkanoic acid solution and, if necessary, another chain extender. The neutralization, water dispersion, and solvent removal are the same as in the method (1). The amount of the chain extender used for chain extension is preferably such that the equivalent ratio of the urethane prepolymer to the isocyanate group is in the range of NCO / active hydrogen = 1 / 0.8 to 1 / 1.2.

  In the method of neutralizing the acrylic monomer solution of the urethane prepolymer of the above method (3), dispersing in water, chain-extending the urethane prepolymer with a chain extender, and radical polymerizing the acrylic monomer with a radical initiator The urethane prepolymer is basically produced under the same conditions as in (1) above. However, since an acrylic monomer is used in place of the organic solvent, it is preferable to add a suitable amount of a polymerization inhibitor such as methylethylhydroquinone and react in the presence of oxygen in order to prevent thermal polymerization of the acrylic monomer.

  Examples of the acrylic monomer used in the reaction of the urethane prepolymer include acrylic monomers that basically have no group that reacts with an isocyanate such as a hydroxyl group, a carboxyl group, a silanol group, an amino group, or a glycidyl group. For example, (meth) acrylic acid alkyl ester as methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, (meth) acrylic acid Pentyl, hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, octyl (meth) acrylate, nonyl methacrylate, lauryl (meth) acrylate, methoxyethyl (meth) acrylate, methoxy (meth) acrylate Examples include butyl and ethoxybutyl (meth) acrylate. In addition, monomers having an amide group such as acrylamide, N-butoxymethyl (meth) acrylamide, N-methylacrylamide, N, N-dimethylacrylamide, N-isopropylacrylamide, diacetoneacrylamide, N-vinylformamide, N, N- Contains tertiary amino group monomers such as dimethylaminoethyl methacrylate, N, N-diethylaminoethyl methacrylate, N, N-dimethylaminopropyl methacrylate, nitrogen such as N-vinylpyrrolidone, N-vinylimidazole, N-vinylcarbazole Monomer, cyclopentyl (meth) acrylate, cyclohexyl (meth) acrylate, cycloaliphatic monomer such as isobornyl (meth) acrylate, styrene, α-methylstyrene, phenyl methacrylate Aromatic monomers such as vinyl triethoxysilane, silicon-containing monomers such as γ-methacryloyloxypropyltrimethoxysilane, and fluorine-containing monomers such as octafluoropentyl (meth) acrylate and perfluorocyclohexyl (meth) acrylate. . Other examples include monomers having a polyfunctional unsaturated double bond such as divinylbenzene and trimethylolpropane triacrylate.

  When an acrylic polymer is grafted onto a polyurethane molecular chain, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, glycerin mono (meta) is used during the prepolymer reaction. ) It is performed by adding a small amount of a monomer containing an active hydrogen group such as a hydroxyl group-containing monomer such as acrylate and introducing an unsaturated double bond group into the polyurethane terminal or molecular chain.

  These acrylic monomers are not necessarily good solvents for urethane prepolymers as compared with ordinary organic solvents, and since the solution viscosity becomes high and thus it is difficult to disperse in water, the average molecular weight of the urethane prepolymer is preferably 10,000. Hereinafter, it is more preferable to set it to 6,000 or less. The average molecular weight is a number average molecular weight calculated by measuring the NCO group content. As needed, you may use an organic solvent together in the range which does not exceed the meaning of this invention. In addition, in order to improve the film-forming property at the time of drying the coating film of the resin and improve the flexibility and elongation of the coating film, phthalic acid ester type, adipic acid ester type, phosphoric acid ester type, polyester type, epoxy type, etc. A plasticizer may be added.

  The ratio of urethane prepolymer to acrylic monomer is urethane prepolymer: acrylic monomer = 10: 90 to 90:10 (weight ratio), more preferably urethane prepolymer: acrylic monomer = 20: 80 to 80:20. Is preferred. When the weight ratio of the urethane prepolymer is less than 10, it is difficult to obtain mechanical properties, adhesion to a substrate, wear resistance, flexibility, and the like, which are characteristics of urethane. When the weight ratio of the urethane prepolymer exceeds 90, the weather resistance, which is a characteristic of the acrylic monomer polymer, may not be sufficiently obtained.

  The additional time when an acrylic monomer is further added to the acrylic monomer solution of the urethane prepolymer is not particularly limited, and may be any time before, during or after the neutralization step of the urethane prepolymer described later. Can be added. Further, after the neutralized urethane prepolymer is dispersed in water, an acrylic monomer can be added to the dispersion.

  In order to disperse the acrylic monomer solution of the urethane prepolymer in water, a neutralizing agent is added in the same manner as in the above method (1) to impart self-emulsifying properties to the urethane prepolymer. The ionic group content is preferably such that the average molecular weight of the urethane prepolymer per ionic group is 500 to 4000. When this value is less than 500, film properties and water resistance of the resulting resin may be deteriorated. On the other hand, if it exceeds 4000, the self-emulsifying property of the urethane prepolymer is insufficient, the average particle size of the dispersed particles is increased and the dispersion stability is deteriorated, and a dense film may be difficult to form. It is preferable not to use an external emulsifier also from the viewpoint of the water resistance of the resulting resin coating and the adhesion to the substrate, but the stability of the aqueous dispersion of the acrylic monomer solution of the urethane prepolymer or when polymerizing it. A small amount of an external emulsifier or reactive activator may be used in combination to increase stability. (Here, the external emulsifier means an emulsifier added in addition to the self-emulsifying urethane prepolymer.)

  The method for dispersing the acrylic monomer solution of the urethane prepolymer in water is the same as the method (1) described above. After obtaining the aqueous dispersion, the urethane prepolymer is chain-extended, and then the polymerization is started. The acrylic monomer is polymerized by adding an agent. Either the chain extension of the urethane prepolymer or the polymerization of the acrylic monomer may be performed first or simultaneously. As the chain extender used for the chain extension of the urethane prepolymer, those shown in the above method (1) can be used, and the chain extension conditions are also the same.

  A known polymerization method can be applied to the polymerization of the acrylic monomer in the aqueous dispersion. The radical polymerization initiator can be used together with a water-soluble initiator or an oil-soluble initiator. When using an oil-soluble initiator, it is preferable to add it to the acrylic monomer solution of the urethane prepolymer. These polymerization initiators are usually 0.05 to 5% by weight with respect to the acrylic monomer, and the polymerization temperature is usually 20 to 100 ° C. When a redox initiator is used, a polymerization temperature of 75 ° C. or lower is sufficient.

  As a polymerization initiator, azo compounds such as azobisisobutyronitrile and azobisisobutylvaleronitrile, benzoyl peroxide, isobutyryl peroxide, octanoyl peroxide, cumyl peroxyoctate, t-butylperoxy-2 -Organic peroxides such as ethyl hexanoate, t-butyl hydroperoxide, t-butyl peroxyacetate, lauryl peroxide, di-t-butyl peroxide, di-2-ethylhexyl peroxydine carbonate, persulfuric acid Examples thereof include inorganic peroxide compounds such as potassium, ammonium persulfate, and hydrogen peroxide. The organic or inorganic peroxide compound may be used as a redox initiator in combination with a reducing agent. Examples of the reducing agent include L-ascorbic acid, L-sorbic acid, sodium metabisulfite, ferric sulfate, ferric chloride, Rongalite and the like. The combination and addition method of the polymerization initiator at this time can be arbitrarily selected. Moreover, you may use a well-known chain transfer agent, for example, an octyl mercaptan, a lauryl mercaptan, 2-mercaptoethanol, dodecyl mercaptan, a thioglycerin etc., in order to adjust the molecular weight in the polymerization of an acrylic monomer.

  When the dimethylol alkanoic acid solution of the present invention is used for the production of an aqueous urethane resin, glycols are preferred as alcohol compounds in order to appropriately increase the molecular weight by reaction with an organic polyisocyanate. The carboxyl group content introduced by the dimethylol alkanoic acid for emulsifying the urethane resin is usually 0.5 to 7% by weight in the resin solids, but the dimethylol alkanoic acid content in the dimethylol alkanoic acid solution. The amount to be added is appropriately adjusted according to the balance. In this case, the glycols function as a chain extender for the urethane resin. In order to adjust the physical properties of the resin, other glycols and diamines can be used in combination.

  The aqueous urethane resin obtained has a solid content of usually 15 to 60% by weight. The average particle diameter is usually in the range of 10 to 1000 nm. The aqueous urethane resin can be used for paints, coating agents, adhesives, various binders, impregnating agents and the like.

  The molecular weight of the aqueous urethane resin is usually 5,000 to 500,000 in terms of number average molecular weight in consideration of mechanical properties such as strength and elongation of the dried film. The viscosity is usually 5 to 5,000 mPa · s / 25 ° C. from the viewpoint of ease of handling.

  The dimethylolalkanoic acid solution of the present invention is also useful as an adhesion promoter for coating agents.

  When the coating agent contains an organic solvent capable of dissolving dimethylolalkanoic acid, dimethylolalkanoic acid that is a solid powder can be added as it is. However, in order to dissolve dimethylol alkanoic acid uniformly, sufficient mixing and stirring are required over time, and heating is necessary when dissolution is difficult. In any case, it is difficult to uniformly dissolve the solid powder of dimethylolalkanoic acid in a short time. It is also possible to add dimethylol alkanoic acid dissolved in a normal organic solvent, but because the solubility of dimethylol alkanoic acid is small, only a low-concentration dimethylol alkanoic acid solution can be obtained. As a result, a large amount of organic solvent is mixed into the coating agent, causing problems such as restrictions on the degree of freedom of blending and an increase in volatile organic compounds (VOC).

  On the other hand, since the dimethylol alkanoic acid solution of the present invention is a high concentration alcohol compound solution in advance, it can be easily incorporated into a coating agent. In particular, when glycols or triols are used as the alcohol compound, VOC is reduced because there are almost no volatile components and it can be directly blended into a solventless or coating agent with a small amount of organic solvent, which is preferable.

  The dimethylol alkanoic acid solution of the present invention is suitable as an adhesion imparting agent for urethane-based coating agents using a synthetic resin and / or polyol which may have active hydrogen and a polyisocyanate curing agent which may be blocked. is there. The urethane-based coating agent may take any form such as a one-component type, a two-component type, and a three-component type, but a two-component type coating agent is preferable. In this case, a synthetic resin which may have active hydrogen and / or a two-component solution composed of a polyol and a dimethylolalkanoic acid solution and a polyisocyanate curing agent, or a reaction between an organic polyisocyanate and a polyol. Examples thereof include a two-pack type coating agent comprising a component comprising an isocyanate group-terminated prepolymer and a dimethylolalkanoic acid solution. An organic solvent is mentioned as an arbitrary component in such a coating agent. The urethane-based coating agent includes all coating agents that utilize the reaction between active hydrogen and polyisocyanate. Moreover, said coating agent is not limited to a coating agent, As long as coating operation is included, it is a concept including an adhesive agent, a coating material, printing ink, etc., for example.

  Synthetic resins optionally having active hydrogen include synthetic resins having active hydrogen atoms in the molecule such as polyurethane resin, polyester resin, epoxy resin and acrylic resin, and active in the molecule such as vinyl chloride resin. And a synthetic resin having no hydrogen atom. As the synthetic resin, a resin obtained by reacting or polymerizing raw materials in an organic solvent can also be used. Further, a bulk reaction or polymerized resin, or a solid resin obtained by emulsion polymerization or suspension polymerization in water can be used without solvent or dissolved in an organic solvent. These resins may be thermoplastic resins or thermosetting resins.

  The number average molecular weight of the synthetic resin is usually 100 to 2,000,000, preferably 500 to 1,000,000. When the number average molecular weight is less than 100, the film forming property is poor, and physical properties such as the strength of the cured coating film are insufficient. In addition, when the number average molecular weight exceeds 2,000,000, the compatibility with the dimethylolalkanoic acid solution and the polyisocyanate curing agent is deteriorated as the solubility of the synthetic resin in the organic solvent is reduced, and good adhesion is achieved. It is difficult to get sex.

  The synthetic resin can be used in any form such as solid, solvent-free liquid, solution, dispersion, sol, and powder. And since the preferable form needs to be liquid in the case of reaction of film formation, it is liquid, such as a solution, a dispersion liquid, and sol. In this case, the resin medium may be an organic solvent or water, but is preferably an organic solvent. In this case, the solid content of the synthetic resin is usually 10 to 100% by weight, preferably 20 to 90% by weight, and more preferably 20 to 80% by weight.

  Examples of the organic solvent include ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone, aromatic solvents such as toluene and xylene, ester solvents such as ethyl acetate and butyl acetate, the alcohol solvents described above, and cellosolve. , N-methyl-2-pyrrolidone, dimethylformamide, dimethylacetamide, dimethyl sulfoxide, tetrahydrofuran, methylene dichloride and the like. These solvents may be used alone or in combination of two or more. Aliphatic dibasic acid esters such as phthalic acid ester, trimellitic acid ester, adipic acid ester, citric acid ester, maleic acid polyester, phosphoric acid ester, epoxy ester, paraffin ester, etc. Other plasticizers can also be used.

  Of these synthetic resins, polyurethane resins are preferred. The polyurethane resin may be in any form such as foam, casting elastomer, sealing material, solution type resin, etc. Among them, a solvent type polyurethane resin dissolved in an organic solvent is preferable. The solvent-type polyurethane resin is produced from the aforementioned organic polyisocyanate, polyol, and, if necessary, a chain extender and a molecular weight or viscosity modifier such as monoalcohol, monoamine, alkanolamine. The average molecular weight of the obtained solvent-type polyurethane resin is usually 5,000 to 500,000, and the solid content of the obtained polyurethane resin solution is usually 15 to 60% by weight.

  As a polyol, what is used as said urethane resin raw material can be used as it is.

  Examples of the polyisocyanate curing agent that may be blocked include terminal isocyanate adducts of the organic polyisocyanates and glycols or triols, dimers or trimers of organic polyisocyanates, and organic polyisocyanates. Examples include a burette body, or a solvent-free type organic solvent solution or a plasticizer solution such as a compound in which the terminal isocyanate group is blocked with an oxime compound or a phenol compound.

  In the present invention, when a dimethylol alkanoic acid solution is used as an adhesion-imparting agent, the content of dimethylol alkanoic acid in the coating agent is usually 0.1 to 20% by weight, preferably 0.5 to 10% by weight, based on the solid content. It is.

  In addition, the coating agent may contain additives such as various pigments, colorants, antioxidants, light stabilizers, and curing accelerators as necessary.

  Base materials to which each of the above coating agents is applied include polyolefins such as polyethylene and polypropylene, and surface treated products thereof, polyesters and surface treated products thereof, polystyrene, vinyl chloride, nylon, ABS, polycarbonate, acrylic resins, and the like, and A metal vapor deposition plastic etc. are mentioned. Further, steel and its surface treated products, metals such as copper and aluminum, pre-coated metals, electrodeposition coated plates, glass, ceramics, mortar, concrete, paper, wood and the like can be mentioned.

  EXAMPLES Hereinafter, although an Example demonstrates this invention still in detail, this invention is not limited to a following example, unless the summary is exceeded. Hereinafter, “part” means “part by weight”, and “%” means “% by weight”.

Example 1:
A 1 L separable flask was charged with 233.3 parts of 1,4-butanediol and 100 parts of dimethylolbutanoic acid (hereinafter abbreviated as DMBA), heated and mixed at 70 ° C. for 2 hours, and uniformly containing 30% DMBA. Solution was obtained. The resulting solution was allowed to stand at 25 ° C. for 30 days, but was stable without precipitation or separation. The obtained DMBA solution is designated as composition A.

Examples 2-5
Propylene glycol (Example 2), ethylene glycol (Example 3), glycerin (Example 4) and dipropylene glycol (Example 5) were used as the polyhydric alcohol in the same manner as in Example 1, and propylene was used. Glycol, ethylene glycol and glycerin each obtained a solution containing 50% DMBA, and dipropylene glycol obtained a uniform solution containing 30% DMBA. The resulting solution was allowed to stand at 25 ° C. for 30 days, but was stable without precipitation or separation. Let these solutions be the composition B, the composition C, the composition D, and the composition E, respectively. The results of Examples 1 to 5 are shown in Table 1.

Comparative Example 1:
200 parts of polytetramethylene ether glycol ("PTMG1000" (trade name) average molecular weight 1000, manufactured by Mitsubishi Chemical Corporation) and 17.5 parts of DMBA were charged, mixed in the same manner as in Example 1, and 8% DMBA at 70 ° C. A homogeneous solution containing was obtained. When this solution was allowed to stand at 25 ° C. for 30 days, most of DMBA was precipitated. The dissolved DMBA content was 3%. This solution is referred to as composition F.

Comparative Example 2:
200 parts of polybutylene adipate (“OD-X-668” (trade name) average molecular weight 2000, manufactured by Dainippon Ink and Chemicals, Inc.) 200 parts and 6.2 parts of DMBA were charged, mixed in the same manner as in Example 1, and mixed at 70 ° C. To obtain a homogeneous solution containing 6% DMBA. When this solution was allowed to stand at 25 ° C. for 30 days, most of DMBA was precipitated. The DMBA content in the dissolved part was 2%. This solution is referred to as composition G.

Comparative Example 3:
200 parts of polypropylene glycol ("EXCENOL 2020" (trade name) average molecular weight 2000, manufactured by Asahi Glass Urethane Co., Ltd.) 200 parts and 8.4 parts of DMBA are charged, mixed in the same manner as in Example 1, and contain 4% DMBA at 70 ° C. A homogeneous solution was obtained. When this solution was allowed to stand at 25 ° C. for 30 days, most of DMBA was precipitated. The dissolved DMBA content was 2%. This solution is referred to as composition H. The results of Comparative Examples 1 to 3 are shown in Table 2.

Example 6 (use example as a water-based urethane resin raw material):
200 g of polytetramethylene ether glycol (“PTMG2000” (trade name) average molecular weight 2000, manufactured by Mitsubishi Chemical Corporation), 59.2 g of the composition B obtained in Example 2, tin-based catalyst (Nitto Kasei) “Neostan U-8” (trade name) 0.1 g and 576.9 g of acetone were charged. These raw materials were heated to 50 ° C., mixed and stirred, and uniformly dissolved. Next, 125.4 g of tolylene diisocyanate (“T-80” (trade name) manufactured by Nippon Polyurethane Industry Co., Ltd.) was added, and 5.0 g of triethylamine was gradually added while the exotherm was observed, and reacted at 60 ° C. for 8 hours. And cooled to 40 ° C. The resin solution was uniformly transparent.

  Further, after adding and mixing 9.1 g of triethylamine, 883.3 g of demineralized water was gradually added to disperse the urethane resin in water, and acetone was removed under reduced pressure to obtain a milky white aqueous urethane resin having a solid content of 30%. This was a uniform dispersion without aggregates. The dimethylol alkanoic acid composition of the present invention was liquid and easy to handle, and was suitable as a raw material for producing a high-quality aqueous urethane resin.

Comparative Example 4:
In place of the composition B obtained in Example 2, 29.6 parts of DMBA and 29.6 parts of propylene glycol were charged separately, and reacted in acetone in the same manner as in Example 1, but the DMBA mass was Part of the resin remained on the stirring blade and the inner wall, and the resulting resin solution was slightly turbid. What dispersed this in water contained many aggregates.

Example 7 (use example as adhesion promoter):
The following evaluation was performed assuming a two-component urethane adhesive. 10 parts of the composition A obtained in Example 1 and 53.5 parts of methyl ethyl ketone were added to 100 parts of a polyester bifunctional polyol (“Desmophen 1700” (trade name) average molecular weight 2540, manufactured by Sumika Bayer Urethane Co., Ltd.). The solution was uniformly dissolved to obtain a solution A.

  88.2 parts of TDI / trimethylolpropane adduct polyisocyanate curing agent (Mittech GP105A (trade name) solid content 75 wt%, solvent: ethyl acetate) manufactured by Mitsubishi Chemical Corporation (NCO / OH = 1/1 equivalent) The liquid B was weighed. And A liquid and B liquid were mixed and used for the coating agent. The adhesion was evaluated by the following method. The results are shown in Table 3.

  A corona discharge-treated polyethylene terephthalate (PET) film (thickness 0.1 mm), nylon 6 film (thickness 0.3 mm), untreated aluminum plate (thickness 0.1 mm) is used as the base material. The above solution is applied using a 200 μm doctor blade and dried at 80 ° C. for 1 hour, and then the same base material is bonded together and heat-cured at 80 ° C. for 24 hours for adhesion test. It was a piece. Next, after being left in an environment of 23 ° C. and 60% RH for one day, the test piece was cut to a width of 25 mm, and a tensile tester (“Tensilon RTM-500” (trade name) manufactured by Orientec Co., Ltd.) under the same environment. Was used to measure the peel strength at a speed of 50 mm / min and evaluate the adhesion.

Comparative Example 5:
In the same manner as in Example 7, except that DMBA of composition A obtained in Example 1 was used alone instead of 1,4-butanediol of the same equivalent, Liquid A Was prepared. The B solution of the polyisocyanate curing agent was weighed so that the NCO / OH = 1/1 equivalent ratio with respect to the total OH groups of the A solution, to give a two-component coating agent, and evaluated in the same manner as in Example 7. Went. The results are shown in Table 3.

  In the table, PTMG1000 is manufactured by Mitsubishi Chemical Corporation, polytetramethylene glycol (average molecular weight 1000), OD-X668 is manufactured by Dainippon Ink and Chemicals, polybutylene adipate (average molecular weight 2000), and Exenol 2020 is Asahi Glass. Polyurethane glycol (average molecular weight 2000) manufactured by Urethane Co., Ltd. was used.

  As is clear from Examples 1 to 5 in Table 1 and Comparative Examples 1 to 3 in Table 2, the dimethylol alkanoic acid solution of the present invention contains dimethylol alkanoic acid at a high concentration and is stable as a solution. Good properties. Further, as is clear from Example 6 and Comparative Example 4, it can be seen that the dimethylolalkanoic acid solution of the present invention is useful as a raw material for the aqueous urethane resin. The results of the use examples of the dimethylol alkanoic acid solution of the present invention as an adhesion-imparting agent are shown in Table 3. From Example 7 and Comparative Example 5, the urethane resin was blended with the dimethylol alkanoic acid solution of the present invention. The effect which improves the adhesiveness with respect to the base material is recognized.

Claims (7)

  A dimethylolalkanoic acid solution obtained by dissolving dimethylolalkanoic acid in a solvent, wherein the solvent is an alcohol compound having a molecular weight of 400 or less.   The dimethylolalkanoic acid solution according to claim 1, wherein the dimethylolalkanoic acid is dimethylolbutanoic acid.   The dimethylolalkanoic acid solution according to claim 1 or 2, wherein the alcohol compound is a polyhydric alcohol having two or more hydroxyl groups in the molecule.   A method for producing an aqueous urethane resin, comprising reacting the dimethylolalkanoic acid solution according to any one of claims 1 to 3, an organic polyisocyanate, and a polyol.   An aqueous urethane resin produced by the production method according to claim 4.   It consists of a dimethylol alkanoic acid solution in any one of Claims 1-3, The adhesion imparting agent characterized by the above-mentioned.   A coating agent comprising the adhesion-imparting agent according to claim 6.