Two-component epoxy resin composition

Abstract

To provide a two-pack type epoxy resin composition which is excellent in coating properties such as dryness and curability, while being an aqueous coating material containing no volatile organic solvent, and to provide a two-pack type epoxy resin composition whose characteristics are applicable to other substances other than the coating material.SOLUTION: A two-pack type epoxy resin composition has: a main agent containing at least an epoxy resin, water, and alumina cement in which the hydration reaction is blocked; and a sub agent containing an epoxy resin curing agent for curing the epoxy resin and a basic aqueous solution for releasing the blocking of the hydration reaction of the alumina cement. The two-pack type epoxy resin composition is usable as a resin mortar material, a putty material, an adhesive or a fiber-reinforced plastic, other than a coating material.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a two-component epoxy resin composition. [Background technology]

[0002] Epoxy resin paints, whose main components are aromatic epoxy resins such as bisphenol A epoxy resin and bisphenol F epoxy resin, have traditionally been widely used as factory floor paints due to their excellent durability and chemical resistance. Conventionally, epoxy resin paints have generally been made low viscosity by blending volatile organic solvents to improve paint workability.

[0003] Furthermore, in order to ensure the shelf life (pot life) of epoxy resin paints until use, two-part paint compositions have been proposed and are being used, each containing an epoxy resin and a curing agent that cures the epoxy resin.

[0004] In response to recent demands for low VOC content, calls for a shift to water-based epoxy resin paints has been heard for some time (see, for example, Patent Document 1). However, there is still a high demand for organic solvent-based epoxy resin paints, which offer excellent paint properties such as drying and curing properties, and excellent coating film properties such as durability and chemical resistance.

[0005] Therefore, it is desirable to solve the problems of organic solvent-based epoxy resin paints derived from volatile organic solvents, while also improving paint properties such as poor drying under high humidity conditions, delayed curing at low temperatures, and film thickness reduction due to water evaporation, which are issues that water-based epoxy resin paints have, as well as coating film properties such as durability and chemical resistance.

[0006] In water-based paints, white Portland cement and alumina cement are used as inorganic binders, but they are inferior in physical properties such as thin film formation, stain resistance, and impact resistance, and in handling properties such as paint workability, color matching, and storage stability. For example, they are not commonly used as finishing materials that can be easily applied with a roller or the like. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] International Publication No. 2020 / 110601 Summary of the Invention [Problem to be solved by the invention]

[0008] An object of the present invention is to provide a two-component epoxy resin composition that is a water-based coating material that does not contain volatile organic solvents and yet has excellent coating properties such as drying and curing properties, and another object is to provide a two-component epoxy resin composition whose properties can be applied to products other than coating materials. [Means for solving the problem]

[0009] The above object can be achieved by the following aspects of the present invention. That is, one aspect of the two-component epoxy resin composition of the present invention comprises a base agent containing at least an epoxy resin, water, and a hydration-blocked alumina cement; an epoxy resin curing agent that cures the epoxy resin, and an auxiliary agent containing a basic aqueous solution that unblocks the hydration reaction of the alumina cement; It has.

[0010] In the above aspect, when the coating liquid is prepared by mixing the main agent and the auxiliary agent, the coating liquid preferably has a water content of 5 to 30 mass % and a cured product-forming component content of 85 to 100 mass %.

[0011] In the above aspect, the epoxy resin is preferably a self-emulsifying liquid epoxy resin, and the epoxy resin curing agent is preferably a polyamine.

[0012] The two-component epoxy resin composition of the above embodiment can be used as a coating material.

[0013] Furthermore, by further blending a coarse aggregate into the two-component epoxy resin composition of the above embodiment, it can be used as a resin mortar material.

[0014] Furthermore, by further blending a thickener into the two-component epoxy resin composition of the above embodiment, it can be used as a putty or adhesive.

[0015] In the two-component epoxy resin composition of the above embodiment, a fiber-reinforced plastic can be obtained by mixing the main component and the auxiliary component to prepare a mixed liquid, and then impregnating fibers with the mixed liquid. [Effects of the Invention]

[0016] According to the present invention, a two-component epoxy resin composition can be provided which is a water-based coating material containing no volatile organic solvents and yet has excellent coating properties such as drying properties and curing properties.Furthermore, a two-component epoxy resin composition can be provided which has properties that can be applied to products other than coating materials. [Brief explanation of the drawings]

[0017] [Figure 1] FIG. 1 is a schematic explanatory diagram showing the state of a main component and a sub-component in a two-component epoxy resin composition according to an embodiment of the present invention. [Figure 2] FIG. 2 is a schematic explanatory diagram showing the state of a coating film formed from a coating liquid prepared from the two-component epoxy resin composition according to the present embodiment. [Figure 3] 1 is an optical microscope photograph (100x magnification) of a cross section of a coating film formed with a coating liquid prepared from a two-component epoxy resin composition according to an example. DETAILED DESCRIPTION OF THE INVENTION

[0018] The two-component epoxy resin composition of the present invention was developed for use in coatings, but its unique curing mechanism and properties make it applicable to a variety of uses other than coatings. In the following embodiments, the use as a coating will be mainly described, and applications to other uses will be summarized later.

[0019] <Embodiment of Paint Application> Hereinafter, a two-component epoxy resin composition (hereinafter sometimes simply referred to as "resin composition") according to one embodiment of the present invention for use in a coating material will be described. The resin composition according to this embodiment contains the main component and auxiliary components shown below.

[0020] Base material: At least epoxy resin, water, and hydration-blocked alumina cement · Secondary agent: Epoxy resin hardener that hardens the epoxy resin contained in the main agent, and a basic aqueous solution that unblocks the hydration reaction of the alumina cement contained in the main agent.

[0021] In addition to the above-mentioned essential components, other components contained in the resin composition according to this embodiment are appropriately blended in at least one of these components or as a separate component. Hereinafter, the two-component epoxy resin composition consisting of a main component and a secondary component will be mainly described, and the essential components contained in each of the main component and the secondary component will then be described.

[0022] [(1) Main ingredient] The (1) main component in the resin composition according to this embodiment contains, as essential components, an epoxy resin, water, and alumina cement.

[0023] (epoxy resin) Examples of epoxy resins used in this embodiment include bisphenol-type epoxy resins such as bisphenol A, bisphenol F, bisphenol S, and halogenated bisphenol A; biphenyl-type epoxy resins; alicyclic-type epoxy resins; ester-type epoxy resins such as dibasic acid; and terpene diphenol-type epoxy resins. Also usable are phenol novolac epoxy resins; alkylphenol novolac epoxy resins such as cresol novolac epoxy resins; and bisphenol A novolac epoxy resins. These epoxy resins may be used alone or in combination of two or more.

[0024] The method for producing the epoxy resin used in this embodiment is not particularly limited, and examples thereof include a direct synthesis method or an indirect synthesis method for bisphenol A type epoxy resin and bisphenol F type epoxy resin, a method for obtaining a hydroxyl group-introduced epoxy resin by reacting an epoxy resin with an aliphatic monocarboxylic acid, and a method for obtaining a hydroxyl group-introduced epoxy resin by reacting an epoxy resin with a monophenol or the like.

[0025] The epoxy resin used in this embodiment can be either a self-emulsifying epoxy resin or a non-self-emulsifying epoxy resin. When a non-self-emulsifying epoxy resin is used, it can be emulsified by mixing with an emulsifier or a self-emulsifying resin and dispersed in water. However, for reasons such as the need for shear-generating stirring to forcefully emulsify using an emulsifier, which makes the process complicated, and the difficulty of ensuring performance such as water resistance even when forcedly emulsifying using an emulsifier, the use of a self-emulsifying epoxy resin is preferred. Furthermore, since this is the opposite of general emulsification, in which water is dispersed in the epoxy resin, the use of a self-emulsifying epoxy resin is preferred in order to maintain the uniformity of the paint and improve the uniformity of the coating film formed.

[0026] A self-emulsifying epoxy resin is an epoxy resin that spontaneously forms a dispersion or emulsion upon contact with water without the aid or action of special emulsifiers or dispersants. Specific examples of self-emulsifying epoxy resins include epoxy resins with hydrophilic moieties introduced into them, such as epoxy resins with hydrophilic moieties in the molecule. Specific examples of the hydrophilic moieties include ionic hydrophilic group moieties and nonionic polyalkylene oxide skeletons.

[0027] An epoxy resin having a polyalkylene oxide skeleton in the molecule can be obtained, for example, by reacting an epoxy resin with a polyalkylene glycol in an excess epoxy equivalent by a conventional method. The polyalkylene glycol used in this case is not particularly limited, and examples include alkylene glycols such as ethylene glycol, propylene glycol, and butylene glycol, polyethylene glycols such as diethylene glycol and triethylene glycol, and polypropylene glycols with a degree of polymerization of 2 to 10.

[0028] (water) The water used in this embodiment is not particularly limited, and any of tap water, industrial water, river water, groundwater, deionized water, pure water, etc. can be used without any problems as long as the salt content, sulfur content, etc. is not extremely high, but of course, it is preferable that the amount of impurities is low.

[0029] (alumina cement) The alumina cement used in this embodiment is not particularly limited, and for example, any of the alumina cements of types 1 to 5 specified in Japanese Industrial Standards JIS R2511 (abolished in 2000) can be used.

[0030] The alumina cement used in this embodiment is blocked from hydration. A blocking agent (also called a "hydration stopper") is used to block the hydration of alumina cement. It is known that the blocking agent can stop the hydration of alumina cement and stabilize the suspension.

[0031] Blocking agents that block the hydration reaction of alumina cement are substances whose aqueous solutions are acidic. Specific blocking agents include metaphosphoric acid, phosphorous acid, phosphoric acid, phosphonic acid, and phosphorus-containing compounds that can produce these phosphorus compounds by reacting with water; hydroxycarboxylic acids and their salts; polyacrylic acid and its derivatives; salts of acrylic acid; chelating agents; condensed phosphates; aluminum phosphate; and boric acid. These can be used alone or in combination.

[0032] The mechanism by which the hydration reaction of alumina cement is blocked by the blocking agent is thought to be as follows: When alumina cement comes into contact with water, it immediately reacts to form Ca 2+ and Al 3+ As ions are dissolved, the pH of the water rises. At a certain pH level, alumina cement hydrate precipitates. However, if an acidic blocking agent is present, the dissolved Ca 2+ is trapped, preventing the pH from rising and maintaining the water at a weak acidity, thereby inhibiting the progress of the alumina cement hydration reaction.

[0033] On the other hand, the hydration reaction of alumina cement causes gelation of aluminum hydroxide. This gelled aluminum hydroxide deposits and coats the surface of the alumina cement, and remains stable on the surface of the alumina cement when the water is kept acidic. Therefore, it is presumed that the hydration reaction of the alumina cement has stopped. Note that this mechanism of action for stopping hydration is merely presumed, and the present embodiment is not limited by this mechanism of action.

[0034] In this embodiment, the amount of blocking agent added mainly depends on the acidity of the blocking agent and the amount of alumina cement in the base material. In practice, the amount of blocking agent added is adjusted so that the pH of the base material is preferably 2 to 7, and more preferably 3 to 6.

[0035] If the pH of the base agent becomes too high, there is a concern that the hydration stopping effect will be insufficient, and the shelf life may be insufficient. On the other hand, if the pH of the base agent becomes too low, the base agent may generate heat and enter a pseudo-setting state, which also tends to result in insufficient shelf life. This pseudo-setting phenomenon is thought to be caused by a direct chemical reaction between alumina cement and acid.

[0036] The main component in the resin composition according to this embodiment can be prepared by mixing the above-mentioned essential components with other components that are appropriately blended as described below, and thoroughly stirring the mixture with, for example, a general rotary mixer so as to prevent uneven concentration.

[0037] [(2) Adjuncts] The auxiliary agent (2) in the resin composition according to this embodiment contains, as essential components, an epoxy resin curing agent and a basic aqueous solution.

[0038] (epoxy resin hardener) As the epoxy resin curing agent (hereinafter sometimes simply referred to as "curing agent") used in this embodiment, those typically used as curing agents for epoxy resins can be used as they are. Specific curing agents include, for example, polyamidoamines, polyamines such as aliphatic polyamines and modified polyamines, epoxy resin amine adducts, aromatic amines, hydrazides, dicyandiamide, imidazole, tertiary amines, acid anhydrides, phenolic resins, urea resins, resol resins, amino resins, ketimines, acid-terminated polyester resins, isocyanates, and blocked isocyanates. A combination of these curing agents may be used depending on the purpose. Among these, polyamines are preferred as curing agents for use in this embodiment in terms of the reaction rate with the epoxy resin at room temperature and its control, the mixing viscosity with the epoxy resin and its control, and the mixing stability with an alkaline aqueous solution.

[0039] (basic aqueous solution) The basic aqueous solution used in this embodiment is a material that unblocks the hydration reaction of the alumina cement contained in the main agent and restores the progress of the hydration reaction, and can be called a hydration initiator in contrast to the blocking agent contained in the main agent.

[0040] The basic aqueous solution may be at least one selected from the group consisting of aluminates, hydroxides, carbonates, nitrites, silicates, and borates of alkali metals, and oxides and hydroxides of alkaline earth metals. The type and amount of the hydration initiator may be selected according to the type and amount of the blocking agent contained in the base agent.

[0041] The auxiliary agent in the resin composition according to this embodiment can be prepared by mixing the above-mentioned essential components with other components that are appropriately blended as described below, and thoroughly stirring the mixture with, for example, a general rotary mixer so as to prevent uneven concentration.

[0042] The components contained in the main agent and auxiliary agent described above are commercially available either as they are or in a state where they are blended with water and other components, and are easily available from the market. The resin composition according to this embodiment can be prepared by procuring each component individually, or can be prepared by appropriately using a commercially available composition with a blend and adjusting the blend of the individual components.

[0043] [Other ingredients] In addition to the above-mentioned essential components, the resin composition according to the present embodiment may contain other components as needed, specifically, various additives such as pigments, aggregates such as glass beads, kansui stone, and silica sand powder, anti-precipitation agents, diluents, surface conditioners, and curing accelerators for epoxy resins.

[0044] Examples of pigments include pigments commonly used in paints, and are not particularly limited as long as they do not impair the stability of the resin composition. Examples include various coloring pigments, such as inorganic pigments such as titanium dioxide, yellow lead, iron oxide, and red iron oxide, and organic pigments such as azo pigments and phthalocyanine pigments, as well as extender pigments such as calcium carbonate, talc, alumina, mica, baryte, and precipitated barium sulfate. Aggregates such as glass beads, kansui stone, and silica sand powder can also be used to improve nighttime visibility, thicker coating thickness, and durability. The content of pigments and aggregates is not particularly limited, but is preferably set to a level that does not significantly affect the properties of the final coating film when used as a paint.

[0045] These other components may be contained in either the main agent or the auxiliary agent, or in both. Alternatively, a separate additive (which may be a liquid or a solid such as a powder) containing these other components may be prepared. Furthermore, to adjust the viscosity or concentration, the separate additive may contain water, or the additive may consist solely of water. One or more such separate additives may be used.

[0046] [Mixing ratio] The resin composition according to this embodiment is prepared in a state that can be used as a coating liquid by mixing the main agent, the auxiliary agent, and, if additives are prepared separately, all of the additives in a predetermined mixing ratio, and thoroughly stirring the mixture with, for example, a general rotary mixer so as to prevent uneven concentration.

[0047] The amount of each component constituting the resin composition according to this embodiment is determined so that the final coating solution contains an appropriate amount of each component. Therefore, the amount of each component varies depending on the mixing ratio of the main component and the auxiliary component.

[0048] In this embodiment, when the term "when the main component and auxiliary component are mixed to prepare a coating liquid" or "in the coating liquid" is used, it means that the main component and auxiliary component are mixed, and if there are any separate additives, the additives are also mixed to prepare the final "coating liquid." Hereinafter, the final coating liquid may be simply referred to as the "coating liquid."

[0049] In this embodiment, the amount of epoxy resin and epoxy resin curing agent blended is preferably within the range of 25 to 85% by mass, and more preferably within the range of 45 to 75% by mass, of the coating liquid. If the amount of epoxy resin and epoxy resin curing agent is too large, the amount of water that can be blended becomes too small to be considered a water-based coating, and if the amount is too small, the water and alumina cement cannot be properly dispersed in the mixture of epoxy resin and epoxy resin curing agent, which are both undesirable.

[0050] In this embodiment, the amount of epoxy resin curing agent to be added cannot be generalized because it varies depending on the type of epoxy resin curing agent used, the combination with the epoxy resin, and the desired paint or coating film properties. Generally, the amount of epoxy resin curing agent added is such that the equivalent weight of the epoxy resin curing agent (the amine equivalent if the epoxy resin curing agent is an amine) is approximately the same as the epoxy equivalent weight of the epoxy resin. However, depending on the desired coating film properties, it is also acceptable to add an excess amount of either the epoxy equivalent weight or the equivalent weight of the epoxy resin curing agent.

[0051] In this embodiment, the amount of alumina cement blended in the coating liquid is preferably within the range of 7.5 to 50 mass %, and more preferably within the range of 15 to 35 mass %. If the amount of alumina cement is too large, the water and alumina cement cannot be properly dispersed in the mixture of epoxy resin and epoxy resin curing agent, and if it is too small, the amount of water that can be blended becomes so small that it cannot be called an aqueous coating, and both are undesirable.

[0052] In this embodiment, the amount of basic aqueous solution to be added should be an amount sufficient to neutralize the acid of the blocking agent contained in the base agent or more. When the pH at the alumina cement interface becomes 8 or higher through neutralization, the hydration reaction of the alumina cement resumes. To obtain an appropriate hydration rate, a pH of 9 or higher is preferable.

[0053] Furthermore, because the basic aqueous solution is blended with the curing agent, it is preferable that the concentration be such that it completely dissolves in the epoxy resin curing agent, such as the amine, used. More preferably, a basic aqueous solution with a pH of approximately 13-14 is blended with the curing agent, and the blending amount is such that the pH is maintained so that the hydration rate matches the curing rate of the resin mixture after mixing with the base resin. That is, if the blending amount of the basic aqueous solution is too small, hydration may not be complete, resulting in a water-containing cured resin, which may hinder the proper resin performance. If the blending amount is too large, hydration may proceed too quickly, resulting in a reduction in the intended usable life and a deterioration in the finished surface, both of which are undesirable. As mentioned above, the specific appropriate blending amount of the basic aqueous solution varies depending on the type and blending amount of the alumina cement, blocking agent, and epoxy resin curing agent.

[0054] In this embodiment, the water content in the coating solution is preferably within the range of 5 to 30% by mass, and more preferably within the range of 10 to 20% by mass. If the amount of water relative to the alumina cement is too high, excess water will be generated that is not consumed in the hydration reaction. This excess water must be evaporated during curing of the coating film, which reduces the benefits of the present invention, such as resistance to the effects of humidity and temperature, as described below, and resistance to film thickness reduction due to water evaporation. Furthermore, if the amount of water and dispersed alumina cement is too high, hydrates will be dispersed in the epoxy resin, which may result in a loss of the characteristics of the resulting cured product. On the other hand, if the amount of water is too low, the coating solution will not be suitable for being called aqueous, and the viscosity of the coating solution will not be sufficiently reduced, which may result in reduced paintability, which is undesirable.

[0055] The above water amounts are the conditions for a typical trowel-applied epoxy resin-based floor paint that requires a certain coating thickness (for example, about 1000 μm or more), but by using an excess amount of water that exceeds the above range (for example, a water content of more than 30% by mass and not more than 60% by mass in the coating solution), the viscosity can be further reduced, making roller application possible and the coating film thinner (for example, about 100 μm or less).In this case, the excess water must be removed by evaporation, so it is important to note that the time until the coating film hardens depends on the amount applied and the coating environment.

[0056] In this embodiment, the content of the cured product-forming component in the coating liquid is preferably 85 to 100% by mass, more preferably in the range of 95 to 100% by mass, and particularly preferably close to 100% by mass.

[0057] The term "hardened product-forming components" as used here refers to all components of the coating solution that become hardened through the epoxy resin curing reaction and through the alumina cement hydration reaction. Regarding water, the amount consumed by the alumina cement hydration reaction to become hardened corresponds to the hardened product-forming components, while the excess water not used in the hydration reaction does not correspond to the hardened product-forming components. Experimentally, the amount of hydration of alumina cement is affected by factors such as the concentration and amount of the basic aqueous solution used to unblock the block and the extender pigment used. However, empirically, it is estimated that approximately 90% of the water by mass of the alumina cement mixed is fixed within the coating film through hydration (i.e., corresponds to the hardened product-forming components).

[0058] In this embodiment, part or all of the water that contributes to the coating suitability of the coating solution is used in the hydration reaction of the alumina cement and becomes a hardened product-forming component. Therefore, the content of the hardened product-forming component in the coating solution can be made 100 mass % or approach 100 mass %, which makes it possible to suppress a decrease in film thickness due to evaporation of the solvent.

[0059] The content of the cured product-forming component in the coating liquid can be determined by producing a cured product and measuring the change in weight. In this embodiment, as an example, the content of the cured product-forming component was determined by the following method.

[0060] A mold (e.g., a polypropylene mold) with a depth of 4 mm and a diameter of 65 mm was prepared, from which the cured product would be easily removed. The mass a (g) of the mixture that would result in a thickness of 4 mm was calculated from the specific gravity of the mixture, and this mass a of the mixture was poured into the mold to produce a cured product. Since the weight loss would be calculated as a percentage later, an accuracy of ±5% for the poured mass was sufficient. The mixture was then kept in a constant environment (temperature 23°C, humidity 50% RH) and after one month, the mass b (g) was measured. The content S (%) of the cured product-forming components was calculated from this measurement and the mass a of the mixture poured into the mold using the following formula (1): S=b / a×100 (1)

[0061] [Coating of resin composition] The resin composition according to this embodiment is used for coating in the form of the coating solution prepared as described above. The coating solution may be applied using a coating tool suitable for the coating thickness and the object to be coated, such as a trowel, spatula, brush, roller, or applicator, or by a known method such as a spray method using a lysine gun or a universal gun.

[0062] [Coating film formation mechanism] Fig. 1 is a schematic explanatory diagram showing the state of the main agent and auxiliary agent (separate agent) in the resin composition according to this embodiment. As shown in Fig. 1, the main agent is in the form of a w / o emulsion in which water droplets (w) are dispersed within an epoxy resin that exhibits hydrophobicity (o). The water droplets contain alumina cement whose hydration reaction has been blocked by a blocking agent. The auxiliary agent is an aqueous liquid containing an epoxy resin curing agent and a basic aqueous solution.

[0063] When the main and secondary agents are mixed and stirred well, first, as shown by arrow a in Figure 1, the epoxy resin in the main agent reacts with the epoxy resin curing agent in the secondary agent, and the epoxy resin curing reaction progresses. At the same time, as shown by arrow b in Figure 1, the blocking agent in the main agent reacts with the basic aqueous solution of the secondary agent, neutralizing the blocking agent. This releases the block on the hydration reaction caused by the blocking agent, and a hydration reaction begins between the alumina cement in the main agent and water, as shown by arrow c1 in Figure 1. Furthermore, as shown by arrow c2 in Figure 1, the alumina cement in the main agent also undergoes a hydration reaction with the water contained in the secondary agent.

[0064] The coating solution prepared by mixing the main agent and the auxiliary agent is in a state where the above-mentioned curing reaction of the epoxy resin and the hydration reaction of the alumina cement proceed simultaneously. Before these reactions proceed, the coating solution is subjected to the coating operation. The coating film formed in this way is formed by the progress of these two reactions.

[0065] FIG. 2 is a schematic explanatory diagram showing the state of a coating film formed from a coating liquid prepared from the resin composition according to this embodiment (hereinafter sometimes abbreviated as "a coating film formed according to this embodiment"). As shown in FIG. 2, the coating film formed according to this embodiment is in a state in which hardened alumina cement hydrate is dispersed in a cured product of the epoxy resin and the epoxy resin curing agent. Furthermore, a small amount of a neutralized product of the blocking agent and the base in the basic aqueous solution remains within the alumina cement hydrate. The neutralized product is present in only a trace amount and is neutral or weakly alkaline, so it has almost no effect on the alumina cement hydrate or the cured epoxy resin.

[0066] The coating film formed by this embodiment as described above is less susceptible to the effects of humidity and temperature because the curing reaction does not involve water evaporation and the curing reaction proceeds inside the coating film. This means that the coating film formed by this embodiment is less susceptible to the effects of humidity and temperature and is less susceptible to film thickness reduction due to water evaporation. Therefore, the coating film formed by this embodiment significantly alleviates problems that occur with general water-based paints, such as poor drying under high humidity conditions, delayed curing at low temperatures, and film thickness reduction due to water evaporation.

[0067] While water-based epoxy resin paints inevitably have poor water resistance, the base agent of the resin composition of this embodiment is composed of water-insoluble raw materials, and the curing agent is mixed with the base agent. As the hydration of alumina cement and neutralization of alkali progress, the water-soluble amine becomes hydrophobic. Furthermore, the curing reaction with the epoxy resin hardly reduces the water resistance of the resulting coating film. The resin composition of this embodiment retains the performance of the cured product of an oil-based liquid epoxy resin paint whose viscosity is adjusted with an organic solvent, while allowing viscosity adjustment with water instead of an organic solvent, and significantly reduces volume loss after curing due to volatilization. Therefore, the coating liquid of this embodiment has a low viscosity, and the coating film formed by this coating liquid has a high solids content after curing.

[0068] The coating film formed by this embodiment mainly exhibits the performance of the cured epoxy resin. In addition, since the alumina cement hydrate is dispersed as a cured product inside the cured epoxy resin, and the alumina cement hydrate functions as a filler, the coating film is expected to have excellent mechanical strength (for example, abrasion resistance).

[0069] The resin composition according to this embodiment is an aqueous agent containing no organic solvents in either the main or secondary agent, and therefore is free from the risk of being subject to various regulations under the Fire Service Act, and is easy to handle.

[0070] <Application to other uses> The resin composition according to this embodiment can be used in applications other than coating applications, such as the applications listed below, due to its unique curing mechanism and properties.

[0071] (Resin mortar material) By further blending coarse aggregate into the resin composition according to this embodiment, it becomes possible to use it as a resin mortar material. In this case, it is preferable to blend the coarse aggregate after preparing a mixed liquid by mixing the main agent and the auxiliary agent. The resin mortar material obtained in this manner is excellent as a resin mortar material in that it has the property of having little volume loss upon hardening.

[0072] The coarse aggregate to be mixed when used as a resin mortar material may be contained in either the main agent or the auxiliary agent, or in both, as with the "other components" already mentioned, or may further be contained in a separately prepared additive.

[0073] The amount of coarse aggregate to be mixed depends on the particle size of the aggregate mixed depending on the required thickness; for example, if a thickness of about 5 mm is desired, silica sand No. 5 or aggregate of a similar particle size should be used in an amount about four times by mass the total amount of the main agent and auxiliary agent of the resin composition according to this embodiment; and if a thickness of about 10 mm is desired, silica sand No. 4 should be used in an amount about five times the total amount. Naturally, the amount can be adjusted or aggregates of various particle sizes can be used in combination depending on the properties desired of the resin mortar material, such as handleability, surface finish, and adhesion to the base material.

[0074] (putty or adhesive) By further blending a thickener into the resin composition according to this embodiment, it becomes possible to use it as a putty or adhesive. In this case, it is preferable to blend the thickener after preparing a mixed solution by mixing the main component and the auxiliary component. The putty or adhesive obtained in this manner has the property of reducing volume loss upon curing, making it excellent as a putty because it is less likely to crack or insufficiently fill gaps or irregularities due to shrinkage. Furthermore, it is excellent as an adhesive because it is less likely to cause a lack of adhesive strength between adherends due to shrinkage.

[0075] The type of thickener is not particularly limited, and any of the general thickeners used in preparing putty materials or adhesives can be used.

[0076] The amount of thickener to be added cannot be generally determined depending on the type and properties of the thickener. However, from the viewpoint of imparting properties as a thickener and maintaining the functionality of the resin composition according to this embodiment, it is desirable that the amount be within the range of 0 to 30 mass % in the coating liquid, and more preferably within the range of 0 to 20 mass %.

[0077] (fiber reinforced plastic) The resin composition according to this embodiment can be used as a fiber-reinforced plastic by further adding fibers. In this case, it is preferable to mix the main component and the auxiliary component to prepare a mixed solution, and then impregnate the fibers with the mixed solution. The fibers may be immersed in or added to the mixed solution.

[0078] The resin composition according to the present embodiment has a low viscosity, which allows it to be easily impregnated into fibers, making it easy to process. Furthermore, the resin composition according to the present embodiment has the property of causing little volume loss upon curing, which makes it difficult for peeling to occur between the resin composition and fibers, making it easy to ensure strength.

[0079] The fibers contained in the resin composition according to this embodiment may be general fibers such as nylon, polyester, hemp, cotton, etc., as well as general reinforcing fibers such as carbon fiber, glass fiber, boron fiber, aramid fiber, etc. The fibers may be woven or nonwoven, and may be formed by impregnating an aggregate of loose fiber particles with the resin composition or by dispersing fiber particles in the resin composition. [Example]

[0080] The present invention will be described below with reference to examples, but the present invention is not limited to the following examples.

[0081] (Example 1: Example of paint application) Example 1 is an example of a floor paint (finishing material) that is applied with a trowel.

[0082] <Preparation of Coating Solution of Example 1> (1) Preparation of the main agent As the epoxy resin, a self-emulsifying epoxy resin, AW-1000 (bisphenol A type liquid epoxy resin, solid content 100%, epoxy equivalent weight 215, manufactured by Chori GLEX Co., Ltd.) was used. In addition, Exalt (manufactured by Kerneos) was used as the alumina cement. Exalt is a water-dispersed product in which the hydration reaction is blocked.

[0083] In addition, ET base color (product name "ET 3W 114 White", a white pigment manufactured by Dainichiseika Color & Chemicals Mfg. Co., Ltd.) was blended as a pigment, ERISYS AED-16L (1,6-hexanediol glycidyl ether manufactured by Huntsman Advanced Materials) as a diluent, and FLOWLEN AC-326F (vinyl ether polymer manufactured by Kyoeisha Chemical Co., Ltd.) as a surface conditioner (antifoaming agent). The composition of the base agent is as shown in Table 1 below.

[0084] [Table 1]

[0085] All of the components (total amount 100) other than the alumina cement in the above formulation were mixed and stirred until uniform, and then the alumina cement was added to prepare the main component of Example 1.

[0086] In this example, only the white ET base color is used as the pigment. However, to achieve a desired color, other ET base colors can be used alone, or multiple ET base colors can be mixed by adjusting the color type and blending amount. If the color development or other finished state is not as desired, additives such as dispersants, color-stabilizing agents, and antifoaming agents can be added to achieve the required quality. Considering the hydration blocking state of the alumina cement, non-basic additives are preferred for the stability of the composition.

[0087] When mixing ET base colors in the formulation of this example, the total blending ratio of all ET base colors used in the blending is 10, and the finish state of the coating film can be adjusted by adding 0.5 to 1 part by mass of AFCONA 6226 (manufactured by Afcona Japan Co., Ltd.) and 0.3 to 0.8 parts by mass of Floren NAF250 (manufactured by Kyoeisha Chemical Co., Ltd.) as additives in an external ratio of 150 (parts by mass).

[0088] (2) Preparation of auxiliary agents The auxiliary agent of Example 1 was prepared by adding 10 parts by mass of a 5% by mass aqueous solution of sodium hydroxide to 30 parts by mass of Fujicure 8167-D (manufactured by T&K TOKA Corporation, modified amine-based curing agent, amine value: 395 to 435, standard compounding equivalent: 85 g / eq) as an epoxy resin curing agent, and mixing them uniformly.

[0089] (3) Preparation of coating solution The main and auxiliary components of each color obtained as described above were mixed in a mixing ratio of main component:auxiliary component = 15:4, and the mixture was thoroughly stirred using a propeller stirrer to make it uniform, thereby preparing the coating solution of Example 1. The specific gravity of the resulting coating solution was 1.35.

[0090] (4) Painting and evaluation test a) Measurement of coating thickness and gloss 10.5 g (1 kg / m²) of the coating solution of Example 1 was applied to a glass plate (float glass plate, 70 × 150 × 3 mm) using a spatula under an environment of 23°C temperature and 50% RH humidity so that the film thickness immediately after application (film thickness before curing) was theoretically 0.75 mm, and the plate was left to stand under the same environment for 20 hours. The gloss (JIS K5600-4-7) of the formed coating film was measured at three points at measurement angles of 20°, 60°, and 85°, and the average values ​​were 62.5, 96.3, and 91.0, respectively, indicating a glossy coating surface.

[0091] The formed coating film was peeled off from the glass plate, its cross section was cut out with a cutter, and the exposed cross section of the coating film was photographed under an optical microscope (100x magnification). The optical microscope photograph of the coating film cross section is shown in Figure 3. In the photograph of Figure 3, the layer in the center of the image is the cross section of the coating film, and the lower surface is the surface that was attached to the glass plate. Note that in the photograph of Figure 3, there is empty space above and below the coating film. When the film thickness was measured from the cross section of the coating film in the photograph, it was approximately 0.76 mm, and the theoretical value and the measured value were almost the same.

[0092] b) Hardness and thickness reduction of the coating film (cured film) 18.0 g of the coating solution of Example 1 (a mass that would result in a thickness of 4 mm calculated from the specific gravity) was poured into a polypropylene mold with a diameter of 65 mm and a depth of 4 mm at a temperature of 23°C and a humidity of 50% RH, and allowed to stand for 20 hours under the same conditions. The mass of the resulting cured film was measured and found to be 18.0 g (mass loss of 0%). The durometer hardness of this cured film (Type D durometer hardness according to JIS K7215; the same applies below) was HDD65, which was sufficiently hard for use as a coating film.

[0093] The samples left under the above conditions were then left to stand (cured) for one month under the same environment (23°C, 50%RH). The mass of the cured film after standing (curing) was measured and found to be 17.6g on average (mass loss 2.22%). This confirmed that most of the coating liquid constituted the cured film.

[0094] c) Reduction in hardness and thickness of coating film (cured film) in high humidity environments 18.2 g of the coating liquid of Example 1 was poured into a mold with a diameter of 65 mm and a depth of 4 mm in an environment of 23°C and 100% RH, and allowed to stand in the same environment for 20 hours. The mass of the resulting cured film was measured and found to be 18.2 g (mass loss 0%). The durometer hardness of this cured film was HDD65, which was the same even in a high humidity environment as in an environment of 23°C and 50% RH.

[0095] (Example 2: Example of putty and adhesive applications) To the coating solution of Example 1, 15% by mass of a zeolite thickener, Milcon MS-2 (manufactured by Showa KDE Co., Ltd.), was added and thoroughly stirred. The mixture exhibited good mixability, and the composition of Example 2, which can be used as an adhesive or putty with good workability, was obtained.

[0096] <Adhesive evaluation test> The adhesive strength of the composition of Example 2 as an adhesive was evaluated in accordance with the Coating Floor Adhesion Strength Test Method NNK-005 (2020) (established by the Technical Committee of the Japan Coating Floor Industry Association). Note that Coating Floor Adhesion Strength Test Method NNK-005 is essentially the same as the test method specified in JIS K5600-5-7 (Mechanical Properties of Coating Film Adhesion (Pull-off Method)) (whereas the JIS uses a cylindrical jig, a square jig was used).

[0097] A concrete slab (30 cm x 30 cm x 6 cm) specified in JIS A 5371 "Precast Unreinforced Concrete Products" was thoroughly sanded with #40 grit sandpaper to remove laitance, and then bonded to a steel jig (4 cm x 4 cm) for adhesive strength testing using the composition of Example 2. The applied amount of the composition of Example 2 (before hardening) was 1.2 kg / m. 2 The test was carried out under an environment of 23°C temperature and 50% RH humidity.

[0098] After confirming that the adhesive had fully hardened three days after bonding, a notch was made around the steel jig, and the testing machine was attached to measure the maximum tensile load. The test was carried out five times, and the fracture surface and adhesive strength were calculated. The test results showed that the adhesive strength (unit: N / mm) was significantly higher than that of the steel material, accompanied by cohesive failure of the substrate. 2 ) was 1.46 on average (minimum 1.04, maximum 2.05), confirming a consistent adhesive strength.

[0099] <Evaluation test as putty material> The composition of Example 2 as a putty was applied to the surface of the same concrete flat plate (30 cm x 30 cm x 6 cm) as used in the <Evaluation test as an adhesive> using a spatula in an amount of 2 kg / m 2This was done in an environment with a temperature of 23°C and a humidity of 50% RH.

[0100] After 4 hours had passed since application under the same conditions, and it was confirmed that the surface had hardened to the extent that it could be overcoated, the coating solution of Example 1 was applied using a spatula so that the film thickness immediately after application (film thickness before hardening) was theoretically 0.75 mm, and the surface was left to stand for 20 hours. All of the processes from application to standing were carried out under the same conditions (temperature 23°C, humidity 50% RH).

[0101] When the cured coating surface was inspected, it was found to be smooth and free of any dents or pinholes caused by the underlying coating.

[0102] The adhesion between layers was confirmed using the same test method as in the <Evaluation test as an adhesive>. However, the square jig was adhered to the surface of the coating film made from the coating liquid of Example 1 with an epoxy resin adhesive (trade name "Bond Quick Mender", manufactured by Konishi Co., Ltd.). The test was carried out five times, and the fracture surface and adhesive strength were calculated. The test results all showed cohesive failure of the test substrate, and the adhesive strength (unit: N / mm 2 ) was 3.76 on average (minimum 3.52, maximum 4.09), confirming that it has high performance as a putty material. [Industrial Applicability]

[0103] As explained above, the two-component epoxy resin composition of the present invention is preferably used as a paint, given the circumstances under which it was developed for paint applications, but it can also be used as a resin mortar material by blending coarse aggregate therewith, as a putty material or adhesive by blending a viscosity agent therewith, and as a fiber-reinforced plastic by impregnating fibers. Of course, applications other than paints are also included in the implementation of the two-component epoxy resin composition of the present invention.

Claims

1. A base agent containing at least an epoxy resin, water, and an alumina cement whose hydration reaction has been blocked by a blocking agent, and which is in a w / o emulsion state in which water droplets (w) are dispersed in the epoxy resin (o); an epoxy resin curing agent that cures the epoxy resin, and an auxiliary agent containing a basic aqueous solution that unblocks the hydration reaction of the alumina cement; and A two-component epoxy resin composition, in the state of a coating liquid containing the main agent and the auxiliary agent, wherein the blending amounts of the epoxy resin and the epoxy resin curing agent are within a range of 25 to 85 mass %, the blending amount of the alumina cement is within a range of 7.5 to 50 mass %, and the blending amount of the basic aqueous solution is an amount sufficient to neutralize the acid of the blocking agent or more.

2. 2. The two-component epoxy resin composition according to claim 1, wherein the coating liquid prepared by mixing the main component and the auxiliary component has a water content of 5 to 30 mass % and a cured product-forming component content of 85 to 100 mass %.

3. 2. The two-component epoxy resin composition according to claim 1, wherein the epoxy resin is a self-emulsifying liquid epoxy resin.

4. 2. The two-part epoxy resin composition of claim 1, wherein the epoxy resin curing agent is a polyamine.

5. The two-component epoxy resin composition according to claim 1, which is used as a coating material.

6. 2. The two-component epoxy resin composition according to claim 1, further comprising coarse aggregate, and used as a resin mortar material.

7. 2. The two-component epoxy resin composition according to claim 1, further comprising a thickener, and used as a putty or adhesive.

8. 2. The two-component epoxy resin composition according to claim 1, further comprising fibers and used as a fiber-reinforced plastic.

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