Epoxy resin emulsion

Abstract

To provide an epoxy resin emulsion excellent in storage stability.SOLUTION: The modified aromatic hydrocarbon-formaldehyde resin has an ethyleneoxide addition ratio of 40% by mass or more and 90% by mass or less, and the cosolvent has an SP value of 10.8 (cal / cm3) 0.5 or less.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to an epoxy resin emulsion. [Background technology]

[0002] Epoxy resins are widely used in the coatings field, such as anti-corrosion coatings for ships, bridges, and onshore and offshore steel structures; in the civil engineering and construction field, for lining, reinforcement, crack repair materials, sealants, injection materials, primers, screeds, top coats, and FRP reinforcement for concrete structures; in building flooring materials, water and sewerage linings, paving materials, and adhesives; in the electrical and electronics field, for example, for die attach materials and insulating sealants; and in the field of fiber-reinforced plastics. These epoxy resins are usually used as solvent-based epoxy resin compositions using a solvent as a solvent. Meanwhile, in recent years, solvent regulations have been strengthened from the viewpoints of environment and safety, and studies are being conducted to make water-based epoxy resin compositions. For example, water-based epoxy resin compositions can be made by adding an emulsifier and water to an epoxy resin to form an emulsion, and using this water-based epoxy resin as the main component. Regarding such emulsifiers, for example, Patent Document 1 discloses aromatic hydrocarbon formaldehyde resins and modified aromatic hydrocarbon formaldehyde resins obtained by adding alkylene oxide to aromatic hydrocarbon formaldehyde resins and modified aromatic hydrocarbon formaldehyde resins, which exhibit excellent emulsifying properties and can impart tackiness and adhesiveness to water-based acrylic resins, urethane resins, and epoxy resins. Furthermore, Patent Document 2 discloses a modified aromatic hydrocarbon formaldehyde resin having excellent emulsifying properties, which is obtained by reacting an aromatic hydrocarbon formaldehyde resin with a polyether monool or a polyether polyol, and an aqueous epoxy resin composition using the same. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-261815 [Patent Document 2] International Publication No. 2021 / 039512 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the modified aromatic hydrocarbon-formaldehyde resins of Patent Documents 1 and 2 had to be added in large amounts, particularly to emulsify or disperse solid epoxy resins in water at room temperature. Furthermore, a cosolvent may be used to emulsify or disperse solid epoxy resins in water, but Patent Documents 1 and 2 provide insufficient consideration of the relationship between the solubility of the cosolvent and the emulsification or dispersion of solid epoxy resins. Therefore, the epoxy resin emulsions obtained using the modified aromatic hydrocarbon-formaldehyde resins of Patent Documents 1 and 2 often have poor long-term storage stability and insufficient storage stability.

[0005] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an epoxy resin emulsion having excellent storage stability. [Means for solving the problem]

[0006] As a result of extensive research, the present inventors have found that an epoxy resin emulsion containing a solid epoxy resin, a specific modified aromatic hydrocarbon-formaldehyde resin, a specific cosolvent, and water can solve the above-mentioned problems.

[0007] [1] An epoxy resin emulsion containing a solid epoxy resin, a modified aromatic hydrocarbon formaldehyde resin obtained by reacting an aromatic hydrocarbon formaldehyde resin with ethylene oxide, a cosolvent, and water; In the modified aromatic hydrocarbon formaldehyde resin, the reaction mass ratio of ethylene oxide to the aromatic hydrocarbon formaldehyde resin (ethylene oxide / aromatic hydrocarbon formaldehyde resin) is 40 / 60 to 90 / 10; The SP value of the cosolvent is 10.8 (cal / cm 3 ) 0.5 The following is an epoxy resin emulsion. [2] The epoxy resin emulsion according to [1], wherein the aromatic hydrocarbon of the modified aromatic hydrocarbon-formaldehyde resin is at least one selected from the group consisting of xylene, toluene, mesitylene, and pseudocumene. [3] The epoxy resin emulsion according to [1] or [2], wherein the weight average molecular weight of the modified aromatic hydrocarbon formaldehyde resin is 300 or more and 100,000 or less. [4] The epoxy resin emulsion according to any one of [1] to [3], wherein the co-solvent is at least one selected from the group consisting of aliphatic chain ketones, cyclic ketones, and glycol ethers. [5] The epoxy resin emulsion according to any one of [1] to [4], wherein the content of the solid epoxy resin in the epoxy resin emulsion is 30% by mass or more and 70% by mass or less. [6] The epoxy resin emulsion according to any one of [1] to [5], wherein the content of the modified aromatic hydrocarbon formaldehyde resin is 0.1 parts by mass or more and 30 parts by mass or less per 100 parts by mass of the solid epoxy resin. [7] The epoxy resin emulsion according to any one of [1] to [6], wherein the content of the co-solvent is 10 parts by mass or more and 30 parts by mass or less per 100 parts by mass of the solid epoxy resin. [Effects of the Invention]

[0008] According to the present invention, an epoxy resin emulsion having excellent storage stability can be provided. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, a mode for carrying out the present invention (hereinafter simply referred to as "the present embodiment") will be described in detail. The following present embodiment is an example for explaining the present invention, and is not intended to limit the present invention to this embodiment. The present invention can be practiced by appropriately modifying it within the scope of its gist. In this specification, definitions that are considered preferable can be adopted arbitrarily, and it can be said that combinations of preferable things are more preferable. In this specification, the expression "XX to YY" means "XX or more and YY or less."

[0010] [Epoxy resin emulsion] The epoxy resin emulsion of the present embodiment is an epoxy resin emulsion containing a solid epoxy resin, a modified aromatic hydrocarbon-formaldehyde resin obtained by reacting an aromatic hydrocarbon-formaldehyde resin with ethylene oxide, a cosolvent, and water, In the modified aromatic hydrocarbon formaldehyde resin, the reaction mass ratio of ethylene oxide to the aromatic hydrocarbon formaldehyde resin (ethylene oxide / aromatic hydrocarbon formaldehyde resin) is 40 / 60 to 90 / 10; The SP value of the cosolvent is 10.8 (cal / cm 3 ) 0.5 The following is the result. The epoxy resin emulsion of this embodiment (hereinafter also simply referred to as "the emulsion of this embodiment") has excellent storage stability. The reason for this is not clear, but is thought to be as follows. The emulsion of the present embodiment contains a modified aromatic hydrocarbon formaldehyde resin in which the reaction mass ratio of ethylene oxide to aromatic hydrocarbon formaldehyde resin (ethylene oxide / aromatic hydrocarbon formaldehyde resin) is 40 / 60 to 90 / 10, and therefore the modified aromatic hydrocarbon formaldehyde resin acts as an emulsifier, improving storage stability. In addition, the SP value of the cosolvent is 10.8 (cal / cm 3 ) 0.5or less, the solid epoxy resin can be dispersed efficiently, and the effect of the aromatic hydrocarbon formaldehyde resin as an emulsifier is further improved, thereby improving the storage stability of the emulsion. From the above viewpoints, it is believed that the epoxy resin emulsion of the present embodiment has excellent storage stability. Furthermore, since the emulsion of this embodiment has the above-mentioned characteristics, it has excellent storage stability, and the resulting cured product also has excellent water resistance and adhesiveness.

[0011] <Solid epoxy resin> In this embodiment, the solid epoxy resin refers to an epoxy resin that is in a solid state at room temperature, and more specifically, refers to an epoxy resin that is in a solid state at 25°C. The solid epoxy resin is not particularly limited, and any of epoxy resins derived from alicyclic alcohols, epoxy resins derived from aromatic alcohols (phenols), and alicyclic epoxy resins can be used. Specific examples include epoxy resins having a glycidyl ether moiety derived from bisphenol A, epoxy resins having a glycidyl ether moiety derived from bisphenol F, and alicyclic aliphatic epoxy resins having an epoxycyclohexyl ring in the molecule.

[0012] From the viewpoint of improving storage stability and improving the water resistance and adhesiveness of the resulting cured product, the epoxy equivalent of the solid epoxy resin is preferably 100 g / eq or more and 800 g / eq or less, more preferably 200 g / eq or more and 700 g / eq or less, even more preferably 300 g / eq or more and 600 g / eq or less, and still more preferably 400 g / eq or more and 550 g / eq or less.

[0013] In the present embodiment, the content of the solid epoxy resin in the epoxy resin emulsion is preferably 30% by mass or more and 70% by mass or less, more preferably 35% by mass or more and 65% by mass or less, and even more preferably 40% by mass or more and 60% by mass or less, from the viewpoint of improving storage stability and improving water resistance and adhesiveness of the obtained cured product.

[0014] <Modified aromatic hydrocarbon formaldehyde resin> In this embodiment, the modified aromatic hydrocarbon-formaldehyde resin is obtained by reacting an aromatic hydrocarbon-formaldehyde resin with ethylene oxide. More specifically, the modified aromatic hydrocarbon-formaldehyde resin can be obtained by reacting an aromatic hydrocarbon-formaldehyde resin with ethylene oxide in the presence of an alkaline catalyst. From the viewpoint of reaction efficiency, potassium hydroxide or the like can be used as the alkaline catalyst when reacting an aromatic hydrocarbon-formaldehyde resin with ethylene oxide. In the present embodiment, the aromatic hydrocarbon formaldehyde resin refers to an unmodified aromatic hydrocarbon formaldehyde resin that is not modified with other functional groups or the like.

[0015] (aromatic hydrocarbon formaldehyde resin) Aromatic hydrocarbon-formaldehyde resins are obtained by reacting aromatic hydrocarbons with formaldehyde. Examples of aromatic hydrocarbons include at least one selected from benzene, toluene, xylene, mesitylene, ethylbenzene, propylbenzene, decylbenzene, cyclohexylbenzene, pseudocumene (1,2,4-trimethylbenzene), biphenyl, methylbiphenyl, naphthalene, methylnaphthalene, dimethylnaphthalene, ethylnaphthalene, anthracene, methylanthracene, dimethylanthracene, ethylanthracene, and binaphthyl. Among these, from the viewpoint of improving storage stability and improving the water resistance and adhesiveness of the resulting cured product, the aromatic hydrocarbon is preferably at least one selected from xylene, toluene, mesitylene, and pseudocumene, and more preferably xylene. As formaldehyde, formalin and paraformaldehyde, which are easily available industrially, as well as compounds that generate formaldehyde, such as trioxane, can be used.

[0016] From the viewpoint of improving storage stability and improving the water resistance and adhesiveness of the resulting cured product, the aromatic hydrocarbon formaldehyde resin preferably contains at least one resin selected from the group consisting of a xylene formaldehyde resin obtained by reacting xylene with formaldehyde, a toluene formaldehyde resin obtained by reacting toluene with formaldehyde, a mesitylene formaldehyde resin obtained by reacting mesitylene with formaldehyde, and a pseudocumene formaldehyde resin obtained by reacting pseudocumene with formaldehyde, and more preferably contains a xylene formaldehyde resin.

[0017] The aromatic hydrocarbon-formaldehyde resin may be a commercially available product or may be prepared by a known method. Examples of commercially available products include "Nikanol H" and "Nikanol LL" manufactured by Fudow Co., Ltd. Known methods include, for example, the method described in Japanese Patent Publication No. 37-5747, in which aromatic hydrocarbon and formaldehyde are subjected to a condensation reaction in the presence of a catalyst.

[0018] In this embodiment, the reaction mass ratio of ethylene oxide to aromatic hydrocarbon formaldehyde resin in the modified aromatic hydrocarbon formaldehyde resin (ethylene oxide / aromatic hydrocarbon formaldehyde resin) is 40 / 60 to 90 / 10, preferably 45 / 55 to 85 / 15, and more preferably 50 / 50 to 80 / 20. When the ethylene oxide addition ratio of the modified aromatic hydrocarbon formaldehyde resin is within the above range, the modified aromatic hydrocarbon formaldehyde resin can efficiently function as an emulsifier, and the storage stability of the emulsion of this embodiment is further improved. Furthermore, the water resistance and adhesion of a cured product using the emulsion of this embodiment are further improved.

[0019] In the present embodiment, the number of repeating ethylene oxide-derived structural units in the structure of the modified aromatic hydrocarbon formaldehyde resin is preferably 10 or more and 160 or less, more preferably 20 or more and 150 or less, and even more preferably 30 or more and 140 or less, from the viewpoint of improving storage stability and improving water resistance and adhesion of the obtained cured product. The number of repeating units derived from ethylene oxide can be calculated using the following formula. Number of repeating units derived from ethylene oxide=(hydroxyl group equivalent of aromatic hydrocarbon-formaldehyde resin×feed weight ratio of ethylene oxide) / (molar mass of ethylene oxide×feed weight ratio of aromatic hydrocarbon-formaldehyde resin)

[0020] Examples of the aromatic hydrocarbon of the modified aromatic hydrocarbon formaldehyde resin include at least one selected from benzene, toluene, xylene, mesitylene, ethylbenzene, propylbenzene, decylbenzene, cyclohexylbenzene, pseudocumene (1,2,4-trimethylbenzene), biphenyl, methylbiphenyl, naphthalene, methylnaphthalene, dimethylnaphthalene, ethylnaphthalene, anthracene, methylanthracene, dimethylanthracene, ethylanthracene, and binaphthyl. Of these, from the viewpoint of improving storage stability and improving the water resistance and adhesion of the resulting cured product, the aromatic hydrocarbon is preferably at least one selected from xylene, toluene, mesitylene, and pseudocumene, and more preferably xylene.

[0021] In this embodiment, the weight average molecular weight of the modified aromatic hydrocarbon formaldehyde resin is preferably 300 or more and 100,000 or less, more preferably 700 or more and 30,000 or less, and even more preferably 1,000 or more and 10,000 or less, from the viewpoint of improving storage stability and improving the water resistance and adhesiveness of the resulting cured product. The weight average molecular weight of the modified aromatic hydrocarbon formaldehyde resin can be determined by gel permeation chromatography (GPC) as a value converted into standard polystyrene.

[0022] In the present embodiment, the HLB value (hydrophile-lipophile balance) of the modified aromatic hydrocarbon formaldehyde resin is preferably 10.0 or more and 20.0 or less, more preferably 11.0 or more and 19.0 or less, and even more preferably 12.0 or more and 18.0 or less, from the viewpoint of improving storage stability and improving the water resistance and adhesiveness of the resulting cured product. The HLB value indicates the affinity of the modified aromatic hydrocarbon formaldehyde resin for water and oil, and can be calculated by the Griffin method using the following formula: HLB value = 20 × [(molecular weight of hydrophilic group contained in modified aromatic hydrocarbon formaldehyde resin) / (molecular weight of modified aromatic hydrocarbon formaldehyde resin)] Examples of the hydrophilic group in the above formula include a hydroxy group and ethylene oxide.

[0023] In this embodiment, it is difficult to identify the structure of the aromatic hydrocarbon formaldehyde resin (unmodified aromatic hydrocarbon formaldehyde resin) by analysis. Similarly, it is also difficult to identify the structure of the modified aromatic hydrocarbon formaldehyde resin that is made from the aromatic hydrocarbon formaldehyde resin (unmodified aromatic hydrocarbon formaldehyde resin) by analysis.

[0024] In the present embodiment, the content of the modified aromatic hydrocarbon formaldehyde resin in the emulsion is preferably 0.1 parts by mass or more and 30 parts by mass or less, more preferably 1 part by mass or more and 20 parts by mass or less, even more preferably 1.5 parts by mass or more and 15 parts by mass or less, and still more preferably 2 parts by mass or more and 12 parts by mass or less, relative to 100 parts by mass of the solid epoxy resin, from the viewpoint of improving storage stability and improving the water resistance and adhesiveness of the resulting cured product.

[0025] <Co-solvent> The emulsion of this embodiment contains a cosolvent, and therefore has improved storage stability. In this embodiment, the SP value (solubility parameter) of the cosolvent is 10.8 (cal / cm3 ) 0.5 It is preferably 6.0 (cal / cm 3 ) 0.5 More than 10.8(cal / cm 3 ) 0.5 Less than 7.0 (cal / cm 3 ) 0.5 More than 10.7(cal / cm 3 ) 0.5 More preferably, 8.0 (cal / cm 3 ) 0.5 More than 10.7(cal / cm 3 ) 0.5 When the SP value of the co-solvent is within the above range, the solid epoxy resin can be dispersed efficiently, and the effect of the aromatic hydrocarbon-formaldehyde resin as an emulsifier is further improved, resulting in further improved storage stability. In this embodiment, the SP value of the cosolvent is a value calculated by the Hildebrand solubility parameter formula below. (Hildebrand solubility parameter equation) SP value (solubility parameter) = (ΔH V -RT) 0.5 / V 0.5 ΔH V : Enthalpy of evaporation of cosolvent R: gas constant T: Temperature V: Molar volume of the cosolvent

[0026] In this embodiment, the boiling point of the cosolvent is preferably 80° C. or higher and 280° C. or lower, more preferably 100° C. or higher and 260° C. or lower, and even more preferably 110° C. or higher and 260° C. or lower, from the viewpoint of improving storage stability.

[0027] In this embodiment, the co-solvent is preferably at least one selected from aliphatic chain ketones, cyclic ketones, and glycol ethers, from the viewpoint of improving storage stability and improving the water resistance and adhesiveness of the resulting cured product. The aliphatic chain ketone is preferably at least one selected from methyl ethyl ketone (SP value 8.9) and methyl isobutyl ketone (SP value 8.3), and more preferably methyl isobutyl ketone. The cyclic ketone is preferably at least one selected from cyclopentanone (SP value 10.1) and cyclohexanone (SP value 9.9), and more preferably cyclopentanone. Glycol ethers include ethylene glycol monopropyl ether (SP value 10.5), ethylene glycol monoisopropyl ether (SP value 10.2), ethylene glycol mono(2-ethylhexyl) ether (SP value 9.3), ethylene glycol dimethyl ether (SP value 8.7), diethylene glycol dimethyl ether (SP value 8.9), diethylene glycol dibutyl ether (SP value 8.3), triethylene glycol dimethyl ether (SP value 9.0), propylene glycol monomethyl ether (SP value 10.7), propylene glycol monoethyl ether (SP value 10.2 ... At least one selected from ethylene glycol monopropyl ether (SP value 9.8), propylene glycol monobutyl ether (SP value 9.7), dipropylene glycol butyl ether (SP value 9.4), ethylene glycol monopropyl ether acetate (SP value 8.9), and propylene glycol monomethyl ether acetate (SP value 9.9) is preferred, and at least one selected from ethylene glycol mono(2-ethylhexyl) ether, diethylene glycol dibutyl ether, propylene glycol monobutyl ether, propylene glycol monopropyl ether, and propylene glycol monomethyl ether is more preferred. In this embodiment, the co-solvent is more preferably at least one selected from the group consisting of methyl isobutyl ketone, cyclopentanone, ethylene glycol mono(2-ethylhexyl) ether, diethylene glycol dibutyl ether, propylene glycol monobutyl ether, propylene glycol monopropyl ether, and propylene glycol monomethyl ether.

[0028] In the present embodiment, the content of the co-solvent in the emulsion is preferably 10 parts by mass or more and 30 parts by mass or less, more preferably 12 parts by mass or more and 28 parts by mass or less, and even more preferably 16 parts by mass or more and 24 parts by mass or less, relative to 100 parts by mass of the solid epoxy resin, from the viewpoint of improving storage stability and improving the water resistance and adhesion of the resulting cured coating film.

[0029] <Water> In the emulsion of this embodiment, the solid epoxy resin is dispersed in water and a co-solvent via the modified aromatic hydrocarbon formaldehyde resin. The water may be purified water such as pure water, distilled water, or ion-exchanged water (deionized water), tap water, or industrial water.

[0030] In the present embodiment, the water content in the epoxy resin emulsion is preferably from 20% by mass to 60% by mass, more preferably from 25% by mass to 50% by mass, and even more preferably from 30% by mass to 40% by mass, from the viewpoint of improving storage stability and improving water resistance and adhesiveness of the resulting cured product.

[0031] <Other ingredients> The epoxy resin emulsion of this embodiment and the epoxy resin composition described below may contain additives such as antifoaming agents, preservatives, dispersion stabilizers, pH adjusters, leveling agents, tackifiers, silane coupling agents, rust inhibitors, lubricants, curing catalysts, water absorbents, moisture absorbents, and hydrolysis inhibitors, as needed, within the range that does not impair the properties of this embodiment.

[0032] The epoxy resin emulsion of the present embodiment is preferably an oil-in-water emulsion. By using an oil-in-water emulsion, the epoxy resin emulsion has better handleability, can be easily produced, and has improved storage stability.

[0033] <Method for producing epoxy resin emulsion> From the viewpoints of efficient production and improved storage stability, the method for producing the epoxy resin emulsion of the present invention is preferably a production method comprising the following steps 1 and 2 in this order. Step 1: Mixing a solid epoxy resin, a modified aromatic hydrocarbon formaldehyde resin, and a co-solvent under heating to obtain an epoxy resin mixture. Step 2: Adding water to the mixture, stirring, and subjecting it to phase inversion emulsification to obtain an epoxy resin emulsion.

[0034] (Process 1) Step 1 is a step of mixing a solid epoxy resin, a modified aromatic hydrocarbon-formaldehyde resin, and a co-solvent while heating to dissolve the solid epoxy resin and the modified aromatic hydrocarbon-formaldehyde resin, thereby obtaining an epoxy resin mixture. In step 1, the order of mixing the solid epoxy resin, modified aromatic hydrocarbon-formaldehyde resin, and co-solvent is not particularly limited, and the solid epoxy resin, modified aromatic hydrocarbon-formaldehyde resin, and co-solvent may be simultaneously blended and mixed. Furthermore, in step 1, the above-mentioned other components may be further blended and mixed, if necessary.

[0035] In step 1, the raw materials can be mixed using a known stirring device such as a disper.

[0036] In step 1, the temperature of the epoxy resin mixture is preferably 70°C or higher and 130°C or lower, more preferably 80°C or higher and 120°C or lower, and even more preferably 90°C or higher and 110°C or lower, from the viewpoints of sufficiently dissolving the solid epoxy resin and making the mixture more easily dispersible in water in step 2.

[0037] (Process 2) Step 2 is a step of adding water to the mixture obtained in step 1, stirring the mixture, and subjecting it to phase inversion emulsification to obtain an epoxy resin emulsion. In step 2, water is preferably added to the mixture obtained in step 1 while stirring the mixture. Water may be added continuously or in portions, and is preferably added in portions from the viewpoint of making the mixture more easily dispersible in water. When water is added in portions, the number of portions added is preferably 2 to 20 times, more preferably 3 to 15 times, and even more preferably 5 to 10 times, from the viewpoint of improving storage stability. Furthermore, when water is added in portions, the amount of water added in one addition is preferably 1 part by mass or more and 20 parts by mass or less, more preferably 3 parts by mass or more and 15 parts by mass or less, relative to 100 parts by mass of the epoxy resin, from the viewpoint of improving storage stability.

[0038] In step 2, a known stirring device such as a disper can be used as the stirring device. Also, a known emulsifying device such as a high-pressure emulsifying device or an ultrasonic emulsifying device may be used.

[0039] In step 2, water is preferably added after cooling the epoxy resin mixture. In step 2, the temperature of the epoxy resin mixture after cooling is preferably 35°C or higher and 65°C or lower, more preferably 40°C or higher and 60°C or lower, and even more preferably 45°C or higher and 55°C or lower, from the viewpoint of making the mixture more easily dispersible in water.

[0040] [Epoxy resin composition] The epoxy resin composition of the present embodiment contains the above-described epoxy resin emulsion of the present embodiment and an epoxy resin curing agent. The epoxy resin curing agent is not particularly limited, but examples thereof include amine-based epoxy resin curing agents, polyfunctional phenolic epoxy resin curing agents, acid anhydride-based epoxy resin curing agents, amide-based epoxy resin curing agents, etc. Among these, it is preferable to use amine-based epoxy resin curing agents from the viewpoint of improving the water resistance and adhesiveness of the resulting cured product. As the epoxy resin curing agent, from the viewpoint of reaction efficiency and improving the water resistance and adhesiveness of the resulting cured product, a water-based epoxy resin curing agent is preferred, and a water-soluble epoxy resin curing agent and an aqueous emulsion-based epoxy resin curing agent are more preferred.

[0041] When an amine-based epoxy curing agent is used as the epoxy resin curing agent, the molar ratio of the epoxy groups of the solid epoxy resin contained in the epoxy resin composition to the amount of amines in the amine-based epoxy curing agent contained in the epoxy resin composition (epoxy group amount / amine amount) is preferably 0.8 or more and 1.2 or less, more preferably 0.9 or more and 1.1 or less, and even more preferably 1.0, from the viewpoint of improving the water resistance and adhesiveness of the obtained cured product.

[0042] <Method of producing epoxy resin composition> The method for producing the epoxy resin composition of the present invention is not particularly limited, and the composition can be produced by mixing the epoxy resin emulsion of the present invention, the epoxy resin curing agent, water as a solvent, and other components as necessary using known methods and devices. There is no particular limit to the order in which the components that serve as raw materials for the epoxy resin composition are mixed, and the composition may be prepared by simultaneously mixing the epoxy resin emulsion of the present invention, the epoxy resin curing agent, water as a solvent, and other components.

[0043] <Application> The epoxy resin emulsion and epoxy resin composition of the present embodiment have the above-mentioned characteristics and are therefore suitable for use in various paints such as anticorrosion paints, adhesives, flooring materials, sealants, polymer cement mortars, gas barrier coatings, primers, screeds, top coats, sealants, crack repair materials, concrete materials, etc. Anticorrosion paints are used, for example, for painting buildings such as ships, bridges, and factories, as well as other iron structures on land and at sea.

[0044] [Cured product of epoxy resin composition] A cured product of the epoxy resin composition of this embodiment (hereinafter simply referred to as "cured product") can be obtained by curing the above-mentioned epoxy resin composition by various known methods, and may be cured at room temperature or by heating. When curing at room temperature, the curing time may be about 1 to 14 days. The heating conditions may be appropriately selected depending on the solid epoxy resin and the content of each component, but are preferably selected from the range of 60 to 120°C for 90 to 150 minutes, and more preferably from the range of 70 to 90°C for 100 to 140 minutes.

[0045] The form of the cured product of the present invention is not particularly limited and can be selected depending on the application. For example, when the epoxy resin composition is a paint, the cured product of the epoxy resin composition is usually a film-like cured product (cured coating film). A film-like cured product of the present invention is preferred in that it can exhibit excellent water resistance. [Example]

[0046] The present invention will be explained in more detail below with reference to examples and comparative examples, but the present invention is not limited to these examples in any way. The evaluation methods employed in the present examples and comparative examples are as follows.

[0047] <Production of modified aromatic hydrocarbon formaldehyde resin> Production Example 1 (Production of Modified Aromatic Hydrocarbon Formaldehyde Resin 1) A heat-resistant vessel equipped with a thermometer, a stirrer, a nitrogen inlet pipe, a condenser, and an alkylene oxide inlet pipe was charged with 100 parts by mass of Nikanol LL (xylene formaldehyde resin, manufactured by Fudow Co., Ltd., weight-average molecular weight: 556, hydroxyl value: 40 mgKOH / g, viscosity (25°C): 4700 mPa·s, hydroxyl equivalent: 1320 g / eq, state (25°C): liquid) and 0.1 parts by mass of potassium hydroxide, and a reaction was carried out under conditions of a reaction temperature of 155°C and a pressure of 0.2 to 0.4 MPa while intermittently feeding 100 parts by mass of ethylene oxide thereto. After the reaction, acetic acid was added to the reaction solution, and the pH of the reaction solution was adjusted to a range of 6.0 to 6.5 to terminate the reaction, thereby obtaining modified aromatic hydrocarbon formaldehyde resin 1 (weight average molecular weight: 1750, melting point: 48°C, HLB value: 13.2, reaction mass ratio (ethylene oxide / aromatic hydrocarbon formaldehyde resin): 50 / 50, number of repeating ethylene oxide-derived structural units: 30, state (25°C): solid).

[0048] Production Example 2 (Production of Modified Aromatic Hydrocarbon Formaldehyde Resin 2) A heat-resistant vessel equipped with a thermometer, a stirrer, a nitrogen inlet tube, a condenser, and an alkylene oxide inlet tube was charged with 100 parts by mass of Nikanol LL (xylene formaldehyde resin, manufactured by Fudow Co., Ltd., weight-average molecular weight: 556, hydroxyl value: 40 mgKOH / g, viscosity (25°C): 4700 mPa·s, hydroxyl equivalent: 1320 g / eq, state (25°C): liquid) and 0.1 parts by mass of potassium hydroxide, and a reaction was carried out under conditions of a reaction temperature of 155°C and a pressure of 0.2 to 0.4 MPa while intermittently feeding 396 parts by mass of ethylene oxide thereto. After the reaction, acetic acid was added to the reaction solution, and the pH of the reaction solution was adjusted to a range of 6.0 to 6.5 to terminate the reaction, thereby obtaining modified aromatic hydrocarbon formaldehyde resin 2 (weight average molecular weight: 6000 to 7000, melting point: 56°C, HLB value: 17.7, reaction mass ratio (ethylene oxide / aromatic hydrocarbon formaldehyde resin): 80 / 20, number of repeating ethylene oxide-derived structural units: 119, state (25°C): solid).

[0049] [Production of epoxy resin emulsion] Example 1 A heat-resistant container equipped with a thermometer, a stirrer (BL600, manufactured by Shinto Scientific Co., Ltd.), and a condenser was charged with 100 parts by mass of solid epoxy resin (Nippon Steel Chemical & Material Co., Ltd., "Epotohto YD-011," an epoxy resin containing glycidyl ether moieties derived from bisphenol A, epoxy equivalent weight 440-510 g / eq), 19 parts by mass of methyl isobutyl ketone, and 10 parts by mass of modified aromatic hydrocarbon formaldehyde resin 1. The mixture was heated with stirring at 300 rpm to dissolve the solid epoxy resin and reach a liquid temperature of 100°C, yielding a mixture. The mixture was then cooled to 50°C, and 71 parts by mass of pure water was added in seven portions while stirring at 700 rpm, yielding the epoxy resin emulsion of Example 1 (non-volatile content 55% by mass). In Example 1, the amount of water added in each divided addition was 10 parts by mass in the first to sixth additions, and the remaining 11 parts by mass was added in the seventh addition.

[0050] (Examples 2 to 11, Comparative Examples 1 to 4) Epoxy resin emulsions were obtained in the same manner as in Example 1, except that the types and amounts of the modified aromatic hydrocarbon formaldehyde resin and cosolvent, and the amount of water added were changed as shown in Table 1. In Examples 2 to 10 and Comparative Examples 1 to 3, water was added in seven divided additions, as in Example 1. In Example 11 and Comparative Example 4, 64.9 parts by mass of water was added in seven divided additions, with 10 parts by mass added in each of the first to sixth additions, and the remaining 4.9 parts by mass added in the seventh addition.

[0051] [A. Evaluation of Epoxy Resin Emulsion] The epoxy resin emulsions of the examples and comparative examples were evaluated as follows. The evaluation results are shown in Table 1. (A-1) Phase inversion emulsification from W / O to O / W In the production of the above epoxy resin emulsion, pure water was added in portions while stirring the mixture at high speed, and an emulsion sample for measurement was taken when the torque of the stirrer increased. A few drops of the emulsion sample were dispersed in approximately 10 mL of water, and the state was visually observed and evaluated according to the following criteria. (Evaluation criteria) A: The emulsion sample was dispersed in water. B: The emulsion sample did not disperse in water.

[0052] (A-2) Non-dispersed matter in emulsion When the epoxy resin emulsions in the Examples and Comparative Examples were produced, it was confirmed whether or not any undispersed solid matter remained on the wall surface of the heat-resistant container after the production was completed, and the result was evaluated according to the following evaluation criteria. (Evaluation criteria) A: No undispersed solid matter adheres to the wall of the heat-resistant container B: Undispersed solid matter adheres to the wall of the heat-resistant container

[0053] (A-3) One-day static stability of emulsion The epoxy resin emulsions of the Examples and Comparative Examples were left to stand in a dryer at 23°C and 50% RH for one day, and the state at that time was visually inspected and evaluated according to the following evaluation criteria. (Evaluation criteria) A: The epoxy resin emulsion was uniformly dispersed. B: Separation of the water layer and oil layer, or floating on the liquid surface was confirmed.

[0054] [Table 1]

[0055] From Table 1, the reaction mass ratio of ethylene oxide to aromatic hydrocarbon formaldehyde resin in the modified aromatic hydrocarbon formaldehyde resin (ethylene oxide / aromatic hydrocarbon formaldehyde resin) is 40 / 60 to 90 / 10, and the SP value of the cosolvent is 10.8 (cal / cm 3 ) 0.5The epoxy resin emulsions of Examples 1 to 11 below were confirmed to have excellent storage stability. On the other hand, the SP value of the cosolvent is 10.8 (cal / cm 3 ) 0.5 It was confirmed that the epoxy resin emulsions of Comparative Examples 1 to 4, which had larger values, had poor storage stability.

[0056] [B. Evaluation of cured coating film (cured product)] As described below, paints for cured coating films and cured coating films were prepared using the epoxy resin emulsions of Examples 9 to 11 and Comparative Example 4, and then evaluated. The evaluation results are summarized in Table 2. (Preparation of paint for cured coating film) 100 parts by mass of the epoxy resin emulsions of Examples 9 to 11 and Comparative Example 4, 74 parts by mass of WD11M60 (an amine-based epoxy resin curing agent, solids concentration 59% by mass, amine equivalent (as is): 701 g / eq, manufactured by Mitsubishi Chemical Corporation) as an epoxy curing agent, and 73 parts by mass of pure water were mixed using a planetary centrifugal mixer (ARE-310, manufactured by Thinky Corporation) to obtain a coating material for curing a coating film. The molar ratio of the number of epoxy groups in the solid epoxy resin to the amount of amine in the amine-based epoxy resin curing agent (amount of epoxy groups / amount of amine) in the coating material for curing a coating film was adjusted to 1 / 1.

[0057] (B-1) Viscosity of the coating material for hardened coating film The viscosity of the resulting coating material for cured coating film was measured using a B-type viscometer (rotor No. 1, manufactured by Tokyo Keiki Co., Ltd.) at a sample temperature of 25°C and a rotation speed of 3 rpm or 30 rpm. The ratio of the viscosity at a rotation speed of 3 rpm to the viscosity at a rotation speed of 30 rpm was defined as the thixotropy ratio.

[0058] (B-2) Water resistance The obtained coating material for cured coating film was applied to a substrate (SPCC zinc phosphate treated steel plate (manufactured by Paltec Co., Ltd.)) using an applicator so that the thickness after application was 200 μm, and then dried and cured at a temperature of 23°C and a humidity of 50% RH for 7 days to obtain a cured coating film. A drop of pure water was placed on the resulting cured coating film, the water drop was covered with a glass cap (2 cm in diameter), and the film was left to stand for 1 day at 23°C and 50% RH. Immediately after wiping off the water drop, the film was observed and evaluated according to the following criteria. (Evaluation criteria) A: The liquid traces were only on the wetted area. B: The liquid stain extended to the contact area of ​​the glass cap.

[0059] (B-3) Adhesiveness The obtained coating material for cured coating film was applied to a substrate (SPCC zinc phosphate treated steel plate (manufactured by Paltec Co., Ltd.)) using an applicator so that the thickness after application was 200 μm, and then dried and cured at a temperature of 23°C and a humidity of 50% RH for 7 days to obtain a cured coating film. A cross-cut peel test was conducted in accordance with JIS K 5600-5-6:1999. A test sample was prepared by cutting 25 squares at 2 mm intervals into the cured coating film. Cellophane tape was firmly pressed onto the test sample in an atmosphere of 23°C, and the edge of the tape was quickly peeled off at a 45° angle. The number of squares remaining on the substrate was visually confirmed. The test results, based on a six-level classification from 0 to 5 as specified in JIS K 5600-5-6:1999, are shown in Table 1. Classification "0" is the best and "5" is the worst.

[0060] [Table 2]

[0061] From Table 2, it was confirmed that the cured coating films (cured products) of Examples 9 to 11 had excellent adhesiveness. In particular, it was confirmed that Examples 10 and 11 also had excellent water resistance. On the other hand, it was confirmed that Comparative Example 4 had poor adhesion and poor performance as a cured coating film.

Claims

1. solid epoxy resin, a modified aromatic hydrocarbon formaldehyde resin obtained by reacting an aromatic hydrocarbon formaldehyde resin with ethylene oxide; co-solvents, and water An epoxy resin emulsion comprising: In the modified aromatic hydrocarbon-formaldehyde resin, the reaction mass ratio of ethylene oxide to the aromatic hydrocarbon-formaldehyde resin (ethylene oxide / aromatic hydrocarbon-formaldehyde resin) is 40 / 60 to 90 / 10; The SP value of the cosolvent is 10.8 (cal / cm ３ ) ０．５ The following is an epoxy resin emulsion.

2. 2. The epoxy resin emulsion according to claim 1, wherein the aromatic hydrocarbon of the modified aromatic hydrocarbon-formaldehyde resin is at least one selected from the group consisting of xylene, toluene, mesitylene, and pseudocumene.

3. 3. The epoxy resin emulsion according to claim 1, wherein the weight average molecular weight of the modified aromatic hydrocarbon formaldehyde resin is 300 or more and 100,000 or less.

4. The epoxy resin emulsion according to any one of claims 1 to 3, wherein the co-solvent is at least one selected from the group consisting of aliphatic chain ketones, cyclic ketones, and glycol ethers.

5. The epoxy resin emulsion according to any one of claims 1 to 4, wherein the content of the solid epoxy resin in the epoxy resin emulsion is 30% by mass or more and 70% by mass or less.

6. 6. The epoxy resin emulsion according to claim 1, wherein the content of the modified aromatic hydrocarbon formaldehyde resin is 0.1 parts by mass or more and 30 parts by mass or less per 100 parts by mass of the solid epoxy resin.

7. The epoxy resin emulsion according to any one of claims 1 to 6, wherein the content of the cosolvent is 10 parts by mass or more and 30 parts by mass or less per 100 parts by mass of the solid epoxy resin.

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