JP5299420B2 - Emulsion composition containing blocked isocyanate, method for producing the same, aqueous base treatment agent for porous substrate, and aqueous baking coating composition - Google Patents

Abstract

A polyurethane emulsion for use in water-based one-pack type polyurethane resin coating materials employing a blocked isocyanate compound is improved to further improve the coating film performance of coating materials of the emulsion. This emulsion is used also as a primer. An emulsion composition containing a blocked isocyanate is provided which is produced by: reacting polymeric MDI (a1) with a high-molecular polyol (a2) containing a nonionic polar group; blocking the isocyanate groups with a blocking agent (C) to produce a blocked polyisocyanate ingredient (A); reacting an organic polyisocyanate (b1) with a high-molecular polyol (b2) and a carboxylated anionic low-molecular glycol (b3) in the resultant reaction system to produce a carboxylated isocyanate-terminated urethane prepolymer (B); neutralizing the carboxy groups with a neutralizing agent (D); thereafter emulsifying the reaction mixture in water; and then using a chain extender (E) to conduct a chain extension reaction and thereby yield a highly crosslinked polyurethane resin.

Description

  The present invention relates to a blocked isocyanate-containing emulsion composition, a method for producing the same, an aqueous base treatment agent for a porous substrate, and an aqueous baking type coating composition. More specifically, the emulsion forms a core-shell structure and has a small particle size distribution. By narrowing, it is related to the emulsion composition with excellent water dispersibility and storage stability at room temperature and above, and good performance as a coating agent, etc. In addition, the present invention relates to an aqueous base treatment agent for a porous substrate and an aqueous baking type coating composition which are excellent in coating film performance and the like.

Polyurethane resin compositions are used extensively as coating agents (coating agents), and are widely used as paints in various industrial fields such as vehicles, building materials, home appliances, and furniture.
In recent years, such a coating agent has been emphasized as an aqueous (aqueous) composition that does not use an organic solvent from the viewpoints of environmental protection against air and wastewater and work safety in the manufacturing process and implementation. Since it is not used, it is economically advantageous, and is being used more frequently than organic solvent-based compositions.
However, water-based polyurethane resin coatings generally have lower physical properties such as durability and solvent resistance than organic solvent-based coatings, so that various physical properties equivalent to organic solvent-based coatings can be obtained. Consideration of improvement is continued.
In addition, in an aqueous polyurethane resin composition, generally, dispersibility in an aqueous medium is low, and storage stability is insufficient due to high reactivity of an isocyanate group with water. Therefore, improvement of these performances is also important. Yes.

So far, many improvement proposals have been disclosed to improve these performances. As one of the improvement methods, the isocyanate group-terminated urethane prepolymer introduced with a carboxyl group is neutralized to be water-dispersible. Later, a polyurethane emulsion for an aqueous one-component coating agent containing a urethane prepolymer emulsified in water and subjected to a chain extension reaction and a urethane prepolymer that is incompatible with water is presented (see Patent Document 1). Even if the water dispersibility is improved, the coating properties of the coating agent as a whole are still not sufficient.
Further, as a useful improvement method, an aqueous one-component polyurethane resin coating agent using a so-called blocked isocyanate compound is well known (for example, see Patent Document 2). This type of coating is a so-called one-component baking type coating in which the isocyanate group is blocked (blocked) so that crosslinking curing does not proceed at room temperature, and the block of the isocyanate group is removed by heating and the coating layer is cured. In addition, the storage stability is improved, and the coating layer is generally better in various properties such as water resistance, solvent resistance, durability and adhesion than those of a room temperature dry type. Furthermore, in order to improve the storage stability and the like, a baking type water-based block polyurethane coating using an isocyanate compound having a nonionic hydrophilic group and an ionic surfactant is also known (see Patent Document 3). ).
However, these blocked isocyanate-based baking polyurethane coatings still have sufficient durability, solvent resistance, impact resistance, glossiness, etc. compared to organic solvent-based coatings. Furthermore, water dispersibility and storage stability are not fully satisfied.

A non-anionic (nonionic) polyisocyanate is mixed with a carboxyl group-introduced isocyanate group-terminated urethane prepolymer, all isocyanate groups in the mixture are blocked with a blocking agent, and the carboxyl group is neutralized and then emulsified in water. Furthermore, polyurethane emulsions for aqueous one-component coating agents that have undergone chain extension reaction with diamine or the like are also disclosed (see Patent Documents 4 and 5), and the storage stability and water resistance and solvent resistance of the coating are improved. .
However, since the blocked isocyanate is contained in the water-dispersed resin in advance, the effective isocyanate content is restricted at the time of thermal dissociation of the block, and the improvement in performance as a coating agent or an adhesive has not been sufficiently satisfied. .

JP 7-188371 (Abstract and paragraphs 0011, 0015) JP 2005-522559 A (summary and claim 1) JP 10-330454 A (summary and paragraph 0018) Japanese Patent Laying-Open No. 2005-154673 (summary) Japanese Patent Laying-Open No. 2005-247897 (Summary)

As described above in the background art, the water-based polyurethane resin coatings still have various physical properties such as durability and solvent resistance, or impact resistance and gloss as compared with organic solvent-based coatings. It cannot be said that it is sufficient, and further, performance such as water dispersibility and storage stability has not been sufficiently improved.
Under such circumstances, the present inventors have developed a non-anionic (nonionic) polyisocyanate to a carboxyl group-introduced isocyanate group-terminated urethane prepolymer as an improved technique for an aqueous one-component polyurethane resin coating using a blocked isocyanate compound. A polyurethane emulsion for an aqueous one-component coating agent is prepared by mixing, blocking all isocyanate groups in the mixture with a blocking agent, neutralizing carboxyl groups, emulsifying in water, and further performing chain extension reaction with diamine or the like. Already developed, the polyurethane emulsion for water-based one-component coating agents contains a blocked isocyanate in the water-dispersed resin in advance, so that the effective isocyanate content is restricted during thermal dissociation of the block. The storage stability at room temperature and above is not sufficient A.

  Therefore, the present inventors have improved the polyurethane emulsion for the aqueous one-component coating agent to further improve various film properties, and to further improve the water dispersibility and the storage stability of the emulsion. In addition, a mode in which a blocked isocyanate is contained in the water-dispersed resin, a method for imparting a water-dispersible function, a reaction condition such as a selective combination of various reaction materials and a urethanization reaction, and further conditions such as emulsification in water and chain extension The invention that improves the water dispersibility and storage stability, and improves various film performances expressed in the film near the dissociation temperature of the block body, by considering and taking into consideration, etc. Developed and characterized by the uniqueness of the emulsion manufacturing process and the core-shell structure of the emulsion particles. Also be a requirement coating material keying seen, it was previously filed (Japanese Patent Application No. 2006-223683) as a new invention.

  In the prior invention of the polyurethane resin-based blocked isocyanate-containing aqueous emulsion composition and the coating agent using the same, water dispersibility, storage stability of the emulsion, and the coating around the dissociation temperature of the block body are expressed. Various film performances have been sufficiently improved and improved, but the present inventors have aimed to further improve various physical properties in the film of the prior invention and to develop a utilization aspect of the prior invention. This is a problem to be solved by the invention.

In order to solve the problems of the present invention, the present inventors further studied and tried aspects such as containing a blocked isocyanate in a water-dispersed resin and selective combinations of various reaction materials. In the invention, instead of HDI polyisocyanate (polyisocyanate derived from hexamethylene diisocyanate) as the organic polyisocyanate material, MDI polyisocyanate (diphenylmethane diisocyanate polyisocyanate, commonly referred to as polymeric MDI) is used. For example, physical properties such as coating film strength and chemical resistance as paints are further improved, and the impregnation property to porous inorganic base material is improved, which makes it extremely useful as a primer for the base material. It is possible to find out that there is something in the previous invention (prior application invention) This has led to the development of the present invention as a kick-related invention.

  Thus, the basic constitution of the present invention is related to the invention of the prior application, as follows: “Polymeric MDI (a1) and nonionic polar group-containing polymer polyol (a2) are reacted and the isocyanate group is blocked with the blocking agent (C). Then, the block polyisocyanate component (A) is produced, and in the reaction system, the organic polyisocyanate (b1) is reacted with the high molecular polyol (b2) and the carboxyl group-containing anionic low molecular glycol (b3) to produce carboxyl. After producing the group-containing isocyanate group-terminated urethane prepolymer (B) and neutralizing the carboxyl group in the reaction system with the neutralizing agent (D), the reaction mixture is emulsified in water, and the chain extender (E) A block isocyanate-containing emulsion group characterized in that a highly cross-linked polyurethane resin is produced by performing a chain extension reaction with It becomes a thing. ".

That is, the main further features and requirements of the basic invention in the present invention are that a nonionic polar group-containing block polyisocyanate and a carboxyl group-containing isocyanate group-terminated urethane prepolymer are used in combination. A carboxyl group-containing isocyanate group-terminated urethane prepolymer was synthesized in the reaction system in which the block polyisocyanate was produced. As illustrated in FIG. 1A, the nonionic polar group-containing block polyisocyanate is a core component ( Emulsion composition in which a polyurethane resin obtained by neutralizing a carboxyl group-containing isocyanate group-terminated urethane prepolymer and forming a chain is formed into a shell (outer shell portion; black background portion in the figure). It is.
The emulsion is a block-isocyanate-containing emulsion composition having a water-dispersed particle size distribution of 50 to 400 nm and a core / shell weight ratio of 50/50 to 70/30, and the emulsion particle size distribution is very small. As in the invention of the prior application, various film performances such as water dispersibility and storage stability of emulsions at room temperature or higher are sufficiently improved, and film uniformity is exhibited in the film near the dissociation temperature of the block body. Has also been improved.

As an incidental requirement or preferred embodiment in the present invention group, the polymer polyol (b2) has a carbonate skeleton or a phthalate skeleton, the neutralizing agent is an amine compound, the chain extender is a polyamine compound, and an emulsion. The composition is an aqueous one-component baking emulsion.
In addition, as a method for producing the blocked isocyanate-containing emulsion composition of the present invention, the block polyisocyanate component (A) is produced using the polymeric MDI described above in paragraph 0010, and an organic polyisocyanate is used in the reaction system. The main requirement is to produce a carboxyl group-containing isocyanate group-terminated urethane prepolymer (B) by reacting (b1) with a polymer polyol (b2) and a carboxyl group-containing anionic low molecular glycol (b3). It is.
Furthermore, as a main application mode of the blocked isocyanate-containing emulsion composition of the present invention, the blocked isocyanate-containing emulsion composition is used as a curing agent, and the main component contains other resin components such as polyurethane resin, It is an aqueous one-component coating composition, and is an aqueous base treatment agent for porous substrates made of a blocked isocyanate-containing emulsion composition.

By the way, when the present invention is compared with the prior art, it is clear that referring to each patent document described in paragraphs 0003 to 0005 described as the background art and other patent documents in this technical field, Similar to the invention, the present invention is at the tip of the improved technique in the conventional blocked isocyanate-containing emulsion composition, and in the prior inventions of Patent Documents 4 and 5, the emulsion particle size distribution becomes smaller and the water dispersibility and the emulsion are at room temperature or higher. In addition, the storage stability is sufficiently improved, and various film performances such as film strength and film uniformity are further improved.
In the present invention, the nonionic polar group-containing isocyanate derived from the polymeric MDI is blocked to produce a block polyisocyanate, and a carboxyl group-containing isocyanate group-terminated urethane prepolymer is synthesized in the reaction system and emulsified after neutralization. The basic requirements for chain extension and the main feature of emulsion particles having a fine core / shell structure cannot be overstated in each prior art document.

  In the invention of the prior application, as described in the specification of the prior application, the organic polyisocyanate (a1) and the nonionic polar group-containing polymer polyol (a2) are reacted, and the isocyanate group is blocked with the blocking agent (C). When the blocked polyisocyanate component (A) is produced by blocking, HDI polyisocyanate (polyisocyanate derived from hexamethylene diisocyanate) is used as the organic polyisocyanate, as seen in the examples. On the other hand, in the present invention, MDI-based polyisocyanate (diphenylmethane diisocyanate-based polyisocyanate, commonly referred to as polymeric MDI) is used as the organic polyisocyanate. Demonstrated by the examples below Further improvements in physical properties such as coating strength and chemical resistance (organic solvent resistance, alkali resistance and acid resistance) of the roller as well as impregnation, adhesion and water resistance to porous inorganic substrates Therefore, the present invention is an invention different from the prior application invention, and further new compared to the prior application invention. It is obvious that the invention has a remarkable effect.

  In the above, as a means for solving the problems of the present invention, the outline of the present invention was created and the basic configuration and features of the present invention. Therefore, in order to clarify the whole of the present invention, Taking a bird's-eye view of the entire invention, the present invention is composed of the following invention unit groups, the inventions [1] and [2] are the basic inventions, and the inventions below are the basic inventions. Is embodied or embodied. (The invention group as a whole is collectively referred to as “the present invention”.)

[1] Polymeric MDI (a1) is reacted with a nonionic polar group-containing polymer polyol (a2), and an isocyanate group is blocked with a blocking agent (C) to produce a blocked polyisocyanate component (A). In the reaction system, the organic polyisocyanate (b1) is reacted with the polymer polyol (b2) and the carboxyl group-containing anionic low molecular glycol (b3) to produce a carboxyl group-containing isocyanate group-terminated urethane prepolymer (B), After neutralizing the carboxyl group in the reaction system with the neutralizing agent (D), the reaction mixture was emulsified in water and subjected to chain extension reaction with the chain extender (E) to produce a highly crosslinked polyurethane resin. The block isocyanate containing emulsion composition characterized by the above-mentioned.
[2] The blocked isocyanate content in [1], wherein the block polyisocyanate component (A) has a core-shell structure in which a core portion is formed and a highly cross-linked polyurethane resin forms a shell portion Emulsion composition.

[3] The blocked isocyanate content in [1] or [2], wherein the emulsion has a water-dispersed particle size distribution of 50 to 400 nm and a core / shell weight ratio of 50/50 to 70/30 Emulsion composition.
[4] The blocked isocyanate-containing emulsion composition according to any one of [1] to [3], wherein the polymer polyol (b2) has a carbonate skeleton or a phthalate skeleton.
[5] The blocked isocyanate-containing emulsion composition according to any one of [1] to [4], wherein the neutralizing agent (D) is an amine compound and the chain extender (E) is a polyamine compound.
[6] The blocked isocyanate-containing emulsion composition according to any one of [1] to [5], wherein the emulsion composition is an aqueous one-component baking type emulsion.

  [7] Polymeric MDI (a1) is reacted with a nonionic polar group-containing polymer polyol (a2), and an isocyanate group is blocked with a blocking agent (C) to produce a blocked polyisocyanate component (A). In the reaction system, the organic polyisocyanate (b1) is reacted with the polymer polyol (b2) and the carboxyl group-containing anionic low molecular glycol (b3) to produce a carboxyl group-containing isocyanate group-terminated urethane prepolymer (B), After neutralizing the carboxyl groups in the reaction system with a neutralizing agent (D), the reaction mixture is emulsified in water and subjected to chain extension reaction with polyamine (E) to produce a highly crosslinked polyurethane resin. The method for producing a blocked isocyanate-containing emulsion composition according to any one of [1] to [6] .

[8] An aqueous base treatment agent for a porous substrate, comprising the blocked isocyanate-containing emulsion composition according to any one of [1] to [6].
[9] An aqueous base treatment agent for a porous substrate, characterized in that the blocked isocyanate-containing emulsion composition according to any one of [1] to [6] is used as a curing agent and a polyurethane resin is used as a main agent.
[10] An aqueous one-component coating composition comprising the blocked isocyanate-containing emulsion composition according to any one of [1] to [6] as a curing agent and a polyurethane resin as a main component.
[11] An aqueous one-part or two-part composition comprising the blocked isocyanate-containing emulsion composition according to any one of [1] to [5] as a curing agent, and a polyurethane resin as a main component and a coating additive. Liquid baking type coating composition.

In the present invention, in the blocked isocyanate-containing emulsion composition, since the emulsion particles have a fine core / shell structure, the emulsion particle size distribution is reduced, and thus (i) a uniform emulsion free of impurities, and (ii) Water dispersibility and storage stability of emulsion above room temperature are sufficiently improved. (Iii) Various coating performances such as coating strength, coating uniformity and appearance appearing near the dissociation temperature of the block can be improved. It is very useful as an aqueous paint or primer that does not use organic solvents.
In addition, the aqueous emulsion composition of the present invention (iv) can form a uniform film that is not affected by the environmental temperature, and (v) is aqueous, so that it is environmentally safe with respect to the atmosphere and drainage, and in the manufacturing process and enforcement. Work safety is high, and handling (handling) is also good. Furthermore, the aqueous emulsion composition of the present invention has (vi) a simple production process and good productivity, and (vii) excellent compatibility with the main agent of a coating material such as polyurethane resin.
Furthermore, the present invention is (viii) a further improvement in physical properties such as coating strength and chemical resistance (organic solvent, alkali resistance and acid resistance) and drying properties as compared to the prior invention. In addition, the impregnation property, adhesion property, and water resistance to the porous inorganic base material are improved, and it is very useful as a base treatment agent (primer) for the base material.

It is the schematic sectional drawing (a) which shows the core-shell structure in this invention, and the schematic sectional drawing (b) which shows the emulsion structure in the comparative composition A.

Although the present invention has been described in accordance with the basic configuration and features of the present invention as means for solving the problems, the embodiments of the invention of the present invention group described above will be specifically described below in detail. explain.

1. About Blocked Isocyanate-Containing Emulsion Composition (1) Blocked Isocyanate-Containing Emulsion Composition The basic composition in the present invention group, the blocked isocyanate-containing emulsion composition, is a water-based emulsion using a blocked isocyanate compound and its one-component polyurethane. In the invention of the resin coating agent, and in the prior invention (Japanese Patent Application No. 2006-223683), which is a highly crosslinked self-emulsifying aqueous emulsion containing a thermal dissociation type blocked isocyanate, as an organic polyisocyanate material Instead of HDI polyisocyanate (polyisocyanate derived from hexamethylene diisocyanate), MDI polyisocyanate (diphenylmethane diisocyanate polyisocyanate, polyisocyanate) (Limelic MDI).
The emulsion composition of the present invention is further improved in physical properties such as coating film strength and solvent resistance as a coating material by using polymeric MDI, and a porous inorganic substrate. This is a related invention in the previous invention (the invention of the prior application), which has been found to be excellent in impregnation into and very useful as a base treatment agent (primer) for this substrate.

By the way, in the prior art, when preparing a water-based thermally dissociated blocked isocyanate into a paint or an adhesive composition, a high viscosity product is mainly used and water dispersibility and handling properties are poor. Further, when the ratio of the blocked isocyanate was increased to improve the performance, the emulsion was separated at 35 ° C. or higher because nonionic hydrophilic groups were mainly used. Furthermore, film formability and appearance tend to deteriorate due to film repelling and phase separation, and those containing a blocked isocyanate group in the water-dispersed resin in advance have an effective isocyanate content during thermal dissociation of the block. It is limited, and water dispersibility and the storage stability of emulsions at 35 ° C and above are not sufficient, so that sufficient film performance cannot be obtained, and the range of design as a coating composition becomes narrow. It was.
Therefore, the present invention is a technique for solving such conventional problems as in the prior invention.

Thus, the present invention basically uses a nonionic polar group-containing block polyisocyanate and a carboxyl group-containing isocyanate group-terminated urethane prepolymer mainly for the purpose of improving the storage stability and water dispersibility of the emulsion composition. Therefore, the main feature is that a carboxyl group-containing isocyanate group-terminated urethane prepolymer is synthesized in a reaction system in which a nonionic polar group-containing block polyisocyanate is produced, and emulsification and chain extension are carried out after neutralization.
Specifically, the polymeric MDI (a1) and the nonionic polar group-containing polymer polyol (a2) are reacted, and the isocyanate group is blocked with a blocking agent (C) to produce a blocked polyisocyanate component (A). In the reaction system, the organic polyisocyanate (b1) is reacted with the polymer polyol (b2) and the carboxyl group-containing anionic low molecular glycol (b3) to obtain a carboxyl group-containing isocyanate group-terminated urethane prepolymer (B). After the production and neutralization of the carboxyl group in the reaction system with the neutralizing agent (D), the reaction mixture is emulsified in water and subjected to chain extension reaction with the chain extender (E) to obtain a highly crosslinked polyurethane resin. It is a block isocyanate-containing emulsion composition that has been produced.

(2) Core / Shell Structure in Emulsion Composition As described above in paragraphs 0007 to 0008, the block isocyanate-containing emulsion composition of the present invention has a fine core / shell structure (structure that can be said to be a nanocapsule). As shown in FIG. 1A, the nonionic polar group-containing block polyisocyanate serves as a core component (core portion), and neutralizes the carboxyl group-containing isocyanate group-terminated urethane prepolymer. Thus, the dispersion is stable in an emulsion composition in which a strong and flexible highly cross-linked anionic polyurethane having a chain extended to form a shell (outer shell portion).

The emulsion has a water-dispersed particle size distribution of 50 to 400 nm and a weight ratio of core / shell of 50/50 to 70/30, which is a blocked isocyanate-containing emulsion composition. The dispersibility and the storage stability of the emulsion above room temperature are sufficiently improved, and it does not separate over a long period of time. Furthermore, various film performances such as film strength and film uniformity and appearance that are developed around the dissociation temperature of the block can be further improved, and a uniform film can be formed without being affected by the environmental temperature. It is also excellent in compatibility with the main ingredients of coating agents such as modified polyolefin resins.
In FIG. 1 (b), for comparison, a nonionic polar group-containing block polyisocyanate dispersion corresponding to the prior invention described in paragraph 0006 and the like serves as a core component, and a carboxyl group-containing isocyanate group-terminated urethane. The state in which the polyurethane resin obtained by neutralizing the prepolymer and extending the chain partially adheres to the periphery of the core portion is illustrated.

(3) Properties due to the core-shell structure By constituting the core-shell structure, the emulsion composition of the present invention produces a uniform emulsion without impurities in the particle size (particle size) distribution state, Additional features of the present invention are also formed. This specific feature is described above as effect (i) in paragraph 0020.

2. Raw material in block isocyanate-containing emulsion composition (1) Organic polyisocyanate (a1)
As the organic polyisocyanate component (a1) used in the production of the block polyisocyanate component (A) of the present invention, specifically, polymeric MDI is exclusively used as described in paragraph 0009 and the like.
That is, in the prior invention, instead of HDI polyisocyanate (polyisocyanate derived from hexamethylene diisocyanate) as the organic polyisocyanate material, MDI polyisocyanate (polymeric MDI which is diphenylmethane diisocyanate polyisocyanate) is used.

Polymeric MDI is commonly used as a polyisocyanate raw material for polyurethane resins. The commonly known polymeric MDI is binuclear MDI (diphenylmethane diisocyanate) and trinuclear or higher polynuclear (MDI condensation). Body)) (polyphenylene polymethylene polyisocyanate).
Polymeric MDI can be obtained by converting the amino group of the condensation mixture (polyamine) obtained by the condensation reaction of aniline and formalin to an isocyanate group by phosgenation, etc. By changing, the composition (nuclear distribution and isomer composition ratio) of the finally obtained polymeric MDI can be controlled.

Polymeric MDI (a1) used in the present invention includes reaction conditions such as a reaction liquid after conversion to an isocyanate group, a crude product obtained by removing the solvent from the reaction liquid, and a bottom liquid obtained by distilling and separating a part of MDI. Several different mixtures such as separation conditions may be used. The MDI content of the polymeric MDI (a1) is 50% or less, preferably 20 to 40%. If the MDI content exceeds 50%, the average number of functional groups of the polymeric MDI is lowered, and it is difficult to obtain a film having sufficient physical properties. The MDI content is determined by performing gel permeation chromatography (GPC) analysis of the polymeric MDI, and the MDI peak area ratio in the total area of the peaks of all the polymeric MDI components.
The MDI contained in the polymeric MDI (a1) has two benzene rings and two isocyanate groups in one molecule, and is a so-called binuclear body. The isomers constituting MDI are 2,2′-diphenylmethane diisocyanate (2,2′-MDI), 2,4′-diphenylmethane diisocyanate (2,4′-MDI), 4,4′-diphenylmethane diisocyanate (4,4). 4′-MDI). The isomer composition ratio of MDI is not particularly limited, but the 4,4′-MDI content is preferably 70% by mass or more, and preferably 90 to 99.9% by mass because the strength of the resulting coating is improved. . The MDI content of polymeric MDI (a1) and the isomer composition ratio of MDI can be obtained from a calibration curve based on the area percentage of each peak obtained by GPC or gas chromatography.
Moreover, the average number of functional groups of polymeric MDI (a1) is 2.3 or more, and preferably the number of functional groups is 2.3 to 3.1. The isocyanate content is 28 to 33% by mass, preferably 28.5 to 32.5% by mass.
From the viewpoint of storage stability and reactivity of the polyisocyanate composition, the acidity of the polymeric MDI (a1) is preferably 0.001 to 0.2% by mass, and more preferably 0.003 to 0.15% by mass. is there. When the acidity is less than 0.001% by mass, the polyisocyanate composition tends to thicken during storage, and when it exceeds 0.2% by mass, the reaction with the polyol is slowed and curing failure tends to occur. Here, the acidity is a value obtained by converting an acid component that reacts with alcohol at room temperature and liberated into hydrogen chloride, and is a value measured by JISK-1603.

In the polymeric MDI (a1) of the present invention, if necessary, a polyisocyanate other than the polymeric MDI can be used in combination.
For example, urethanized product, urea product, allophanate product, burette product, carbodiimidide product, uretoniminate product, uretdione product, isocyanurate product obtained by reacting MDI or polymeric MDI with active hydrogen group-containing compound, tetramethylene diisocyanate, Aliphatic diisocyanates such as hexamethylene diisocyanate, aliphatic diisocyanates such as 3-methyl-1,5-pentane diisocyanate, lysine diisocyanate, isophorone diisocyanate, hydrogenated tolylene diisocyanate, hydrogenated xylene diisocyanate, hydrogenated diphenylmethane diisocyanate, 2, 4-tolylene diisocyanate, 2,6-tolylene diisocyanate, xylene-1,4-diisocyanate, xylene 1,3-diisocyanate, tetramethyl xylene diisocyanate, m- phenylene diisocyanate, aromatic diisocyanates such as p- phenylene diisocyanate. Furthermore, urethanized products obtained by reacting these isocyanates with active hydrogen group-containing compounds, urea products, allophanate products, burette products, carbodiimidized products, ureton iminate products, uretdione products, isocyanurate products, etc. A mixture of two or more of these may be used.
In the present application, in order to avoid complicated description of the specification, the essential part of the invention is the main description, and in order to simplify the specification, the exemplary list of each compound is concise. Naturally, the essence and extension are not affected.

(2) Nonionic polar group-containing polymer polyol (a2)
In order to impart hydrophilicity to the block polyisocyanate component (A), the polymer polyol compound forming the block polyisocyanate in the present invention uses a polyol compound containing a nonionic polar group, for example, a nonionic polar group. A polyalkylene ether polyol containing a normal alkoxy polar group is used.
Ordinary nonionic polar group-containing polyester polyols and polycarbonate polyols are also used.
As the polymer polyol, those having a number average molecular weight of 500 to 10,000, particularly 500 to 5,000 are preferably used.

(3) Block agent (C)
The blocking agent (C) used in the present invention is not particularly limited, and one or more blocking agents can be appropriately selected from known ones. Examples of the blocking agent include phenolic, alcoholic, active methylene, mercaptan, acid amide, lactam, acid imide, imidazole, urea, oxime, and amine compounds.

More specifically, for example, phenol compounds such as phenol, cresol and ethyl phenol, alcohol compounds such as propylene glycol monomethyl ether, ethylene glycol, benzyl alcohol, methanol and ethanol, and active methylene compounds such as dimethyl malonate and acetylacetone. , Mercaptan compounds such as butyl mercaptan and dodecyl mercaptan, acid amide compounds such as acetanilide and acetic acid amide, lactam compounds such as ε-caprolactam and δ-valerolactam, and acid imide compounds such as succinimide and maleic imide Oxime compounds such as acetoaldoxime, acetone oxime, methyl ethyl ketoxime, and amine compounds such as diphenylaniline, aniline, ethyleneimine Can be mentioned.
In the present invention, among the above-described blocking agents, methyl ethyl ketoxime, ε-caprolactam, and 2-ethylhexanol are preferable from the viewpoint of easy availability and workability.

(4) Organic polyisocyanate (b1)
As the organic polyisocyanate component (b1) used in the production of the carboxyl group-containing isocyanate group-terminated urethane prepolymer (B) of the present invention, a bifunctional organic diisocyanate compound is preferably used. The usual ones are used and are not particularly defined. In order to avoid yellowing of the coating film due to ultraviolet rays, aliphatic or alicyclic diisocyanates are preferred over aromatic diisocyanates.

Specifically, tetramethylene diisocyanate, hexamethylene diisocyanate, lysine diisocyanate, 2-methylpentane-1,5-diisocyanate, 3-methylpentane-1,5-diisocyanate, 2,2,4-trimethylhexamethylene-1, Examples include aliphatic diisocyanates such as 6-diisocyanate, 2,4,4-trimethylhexamethylene-1,6-diisocyanate, and isophorone diisocyanate, cyclohexyl diisocyanate, hydrogenated xylylene diisocyanate, hydrogenated diphenylmethane diisocyanate, hydrogenated trimethylxylylene diene. Illustrative are alicyclic diisocyanates such as isocyanate. These diisocyanates are used individually by 1 type or in mixture of 2 or more types.
Furthermore, these adduct modified products, carbodiimide modified products, allophanate modified products, burette modified products, uretdione modified products, uretoimine, such as allophanate modified polyisocyanates obtained from hexamethylene diisocyanate and monools having 1 to 6 carbon atoms. Modified products, isocyanurate modified products, and the like can also be used.

  As aromatic diisocyanates, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, xylene-1,4-diisocyanate, xylene-1,3-diisocyanate, 4,4'-diphenylmethane diisocyanate, 2, 4'-diphenylmethane diisocyanate, 4,4'-diphenyl ether diisocyanate, 2,2'-diphenylpropane-4,4'-diisocyanate, 3,3'-dimethyldiphenylmethane-4,4'-diisocyanate, m-phenylene diisocyanate, p Examples include -phenylene diisocyanate and naphthylene-1,4-diisocyanate.

(5) Polymer polyol (b2)
The polymer polyol (b2) used in the production of the carboxyl group-containing isocyanate group-terminated urethane prepolymer in the present invention is a polyester polyol or polyesteramide having a normal number average molecular weight of 500 to 10,000, preferably 500 to 5,000. Polyols, polyether polyols, polyether ester polyols, polycarbonate polyols, polyolefin polyols and the like are used, and these polymer polyols may be used in combination.
In consideration of the water resistance of the shell portion, the polymer polyol preferably has a carbonate skeleton or a phthalate skeleton.

  Polyester polyols and polyester amide polyols include polycarboxylic acid derivatives such as polycarboxylic acids, acid esters, acid anhydrides, acid halides, low molecular polyols having a number average molecular weight of less than 500, low molecular polyamines, low molecular amino alcohols, and the like. It is obtained by the reaction of

(6) Carboxyl group-containing anionic low molecular weight glycol (b3)
The carboxyl group-containing anionic low molecular weight glycol used in the production of the carboxyl group-containing isocyanate group-terminated urethane prepolymer (B) of the present invention is obtained by reacting the active hydrogen groups of the hydroxyl groups at both ends with isocyanate groups. Since it is incorporated into the main chain and the free carboxyl group is hydrophilic, it acts to increase the water dispersibility of the prepolymer. The carboxyl group is neutralized to increase the hydrophilicity.
Examples of the carboxyl group-containing anionic low molecular weight glycol include dimethylolpropionic acid and dimethylolbutanoic acid having two terminal hydroxyl groups, other reaction products of polyamine and acid anhydride, dimethylolpropionic acid and dimethylol. Lactone adducts and the like using butanoic acid as an initiator are also used as appropriate.

(7) Neutralizing agent (D)
A normal thing is arbitrarily used as a neutralizing agent of this invention. For example, organic amines such as ethylamine, trimethylamine, triethylamine, triisopropylamine, triethanolamine, triisopropanolamine, morpholine, N-methylmorpholine are preferably used, and inorganic alkalis such as sodium hydroxide and potassium hydroxide, and ammonia Are also illustrated.
In order to improve the weather resistance and water resistance after drying, a highly volatile one that is easily dissociated by heat or an amino alcohol that reacts with a polyisocyanate curing agent is more preferred.

(8) Chain extender (E)
The chain extender is not particularly limited, but the diamine or polyamine compound is more advantageous in physical properties such as water resistance, solvent resistance, and stain resistance because it is more highly crosslinked than a diol compound as a chain extender.
Specific examples of these amine compounds, ethylenediamine diamine (EDA), isophorone diamine (IPDA) is illustrated in the _{polyamine, H 2 N- (C 2 H} 4 NH) n -C 2 H 4 NH 2 (n = 1-8), diethylenetriamine (DETA), triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine and the like are exemplified.

(9) Curing catalyst and curing agent Resinization catalyst (urethanization catalyst) as a curing catalyst (polymerization catalyst) for urethane reaction is used as necessary, and is a metal catalyst such as dibutyltin dilaurate or zinc naphthenate or triethylenediamine. Ordinary curing catalysts such as amine catalysts such as N-methylmorpholine are used, and the reaction rate can be increased and the reaction temperature can be lowered.
As a curing agent for curing the polyurethane resin, hexamethylene diisocyanate (H
DI) or isophorone diisocyanate (IPDI) is used as a trimer or adduct having 3 or more NCO groups in one molecule.

3. Method for Producing Blocked Isocyanate-Containing Emulsion Composition (1) Basic Requirements In the present invention, the method for producing a block isocyanate-containing emulsion composition basically includes polymeric MDI (a1) and nonionic polar group-containing polymer polyol (a2). ), And the isocyanate group is blocked with a blocking agent (C) to produce a blocked polyisocyanate component (A). In the reaction system, organic polyisocyanate (b1), polymer polyol (b2) and carboxyl The group-containing anionic low molecular glycol (b3) was reacted to produce a carboxyl group-containing isocyanate group-terminated urethane prepolymer (B), and the carboxyl group in the reaction system was neutralized with the neutralizing agent (D). After that, the reaction mixture is emulsified in water and added to the chain extender (E) polyamine. By performing a chain extension reaction.
In particular, the non-ionic polar group-containing isocyanate is blocked to form a blocked polyisocyanate, and the emulsion particles have a fine core / shell structure due to the basic requirement of synthesizing the carboxyl group-containing isocyanate group-terminated urethane prepolymer in the reaction system. And the effects of the inventions (i) to (iii) described in paragraph 0020 are brought about.

(2) Reaction conditions The blocking reaction can be carried out according to normal blocking reaction conditions of 20 to 100 ° C, preferably 30 to 90 ° C. At this time, a known urethanization catalyst may be used. The blocking rate is preferably 20 mol% or more, particularly preferably 30 to 50 mol%. If the blocking rate is too low, the strength and durability of the coating tends to be insufficient.
A known urethanization catalyst may be used during the production of the carboxyl group-containing isocyanate group-terminated urethane prepolymer. The reaction temperature is preferably 0 to 100 ° C, particularly preferably 20 to 90 ° C. At this time, it is preferable from the viewpoint of stirring efficiency and the like that it is diluted to an arbitrary solid content with an organic solvent that is inert to the isocyanate group. Examples of the organic solvent include aromatic solvents such as toluene and xylene, aliphatic hydrocarbon solvents such as hexane, alicyclic hydrocarbon solvents such as cyclohexane and isophorone, ketone solvents such as acetone and methyl ethyl ketone, and acetic acid. Ester solvents such as ethyl and butyl acetate, glycol ether ester solvents such as ethylene glycol monoethyl ether acetate and propylene glycol monomethyl ether acetate, glycol ether solvents such as ethylene glycol dimethyl ether, diethylene glycol dibutyl ether and propylene glycol dibutyl ether used.
Neutralization can be carried out according to normal neutralization reaction conditions of 20 to 50 ° C. with any neutralizing agent described in paragraph 0041.

4). Aqueous polyurethane resin emulsion coating composition
(1) Main agent and curing agent The aqueous polyurethane resin coating composition in the present invention is an application mode of the blocked isocyanate-containing emulsion composition which is the basic invention in the present invention, and is used as a coating agent (paint).
The coating composition is basically composed of a main agent and a curing agent, and a blocked isocyanate-containing emulsion composition is used as a curing agent, and a normal polyurethane resin or modified polyolefin resin is appropriately used as the main agent.
Although it is used in a one-component type in which the main agent and the curing agent are mixed in advance, it may be a two-component type in which the main agent and the curing agent are mixed at the time of use in coating construction.

(2) Usage mode The coating composition is applied to various base materials such as metal, plastic, wood, and inorganic materials as a coating agent, and then the coating layer is heated to form a block body. Dissociates, and a high crosslinking reaction occurs between the isocyanate group and the active hydrogen, which is cured and baked.

(3) Function and effect In coating compositions, particularly in the usage mode as paints, various coating performances such as coating strength, coating uniformity and appearance, which are developed near the dissociation temperature of the block, are further improved. A uniform film that is not affected by temperature can be formed.

(4) Additives In order to enhance physical properties and add various other physical properties, as various additives, arbitrarily, flame retardants, plasticizers, antioxidants, ultraviolet absorbers, dyes, pigments, Fillers, internal mold release agents, reinforcing materials, matting agents, conductivity imparting agents, charge control agents, antistatic agents, lubricants, and other processing aids can be used.

5. Aqueous surface treatment agent for porous substrate (1) Surface treatment agent The aqueous surface treatment agent for porous substrate in the present invention is a second application mode of the block isocyanate-containing emulsion composition which is the basic invention in the present invention. It is used as an aqueous surface treatment agent (primer) for porous substrates, particularly for inorganic porous substrates.

(2) Aspect of Use As a base treatment agent, a blocked isocyanate-containing emulsion composition alone or a mixture of a polyurethane resin as a main component and a blocked isocyanate-containing emulsion composition as a curing agent is used as a porous substrate, particularly a slate. It is applied as an undercoat (primer) to an inorganic porous substrate such as a plate, cement plate, calcium silicate plate or gypsum plate, and the surface is sealed. Usually, since a paint or a coating is applied onto the primer, the sealing improves the workability of painting.
The above-mentioned inorganic porous substrate is porous and brittle, and the surface is easily powdered. Since it is a basic substance, the alkaline substance is easily dissolved and eluted on the surface to be coated. When the paint is applied, the paint film is peeled off when the curing tape is removed or when water penetrates or freezes and melts over time, and the surface of the paint film is whitened due to dissolution and dissolution of alkaline substances in the base material. Cause deterioration of the coating film. Therefore, the application | coating process of a surface treating agent like the blocked isocyanate containing emulsion composition of this invention becomes inevitable.

(3) Function and effect The blocked isocyanate-containing emulsion composition of the present invention is practically higher in impregnation and adhesion to the surface of the porous substrate than demonstrated in ordinary resin-based emulsions, as demonstrated in the examples below. It is rich in nature.
Further, as demonstrated in the examples described later, the blocking property (adhesiveness) immediately after drying is low and easy to handle, and the water resistance after aging is also rich.

  In the following, the present invention will be described in more detail by comparing the comparative examples with examples, the configuration of the present invention will be clarified, the rationality and significance of each requirement of the configuration of the present invention, and Demonstrate the superiority of the present invention over the prior art.

[Production of blocked isocyanate-containing emulsion composition]
Polymeric MDI (a1) and nonionic polar group-containing polymer polyol (a2) are reacted, and the isocyanate group is blocked with a blocking agent (C) to produce a blocked polyisocyanate component (A). And reacting the organic polyisocyanate (b1) with the polymer polyol (b2) and the carboxyl group-containing anionic low-molecular glycol (b3) to produce a carboxyl group-containing isocyanate group-terminated urethane prepolymer (B). After neutralizing the carboxyl group in the neutralizing agent (D), the reaction mixture is emulsified in water, and a chain extension reaction is carried out with the polyamine of the chain extender (E).

(Name of component)
(I) Polyisocyanate A: HDI isocyanurate-modified polyisocyanate NCO = 21.2% Average functional group number = 3.7 Made by Nippon Polyurethane Industry Product name: Coronate (registered trademark) HX
(Ii) Polyisocyanate B: Polymeric MDI NCO = 31.1% MDI content = 40% Average functional group number = 2.7 Made by Nippon Polyurethane Industry Brand name: Millionate (registered trademark) MR200
(Iii) Isocyanate A: Isophorone diisocyanate (iv) Polyol A: Polycarbonate diol obtained from 1,6-hexanediol and diethyl carbonate Mn = 2,000
(V) Glycol A: Trimethylolpropane (vi) Anionic hydrophilic group component: 2,2-dimethylolpropionic acid (vii) Chain extender: Diethylenetriamine (viii) Neutralizer: Triethylamine (ix) Nonionic hydrophilic group component : Ethylene glycol monomethyl ether Mn = 800 (x) high boiling point solvent A: dipropylene glycol dimethyl ether (xi) high boiling point solvent B: diethylene glycol diethyl ether (xii) blocking agent: methyl ethyl ketoxime

(Synthesis example of blocked isocyanate-containing emulsion);
Into a 1 L four-necked separable flask equipped with a stirrer, thermometer, and condenser equipped with an impeller blade, 141 g of isocyanate B, 22.5 g of polyol (nonionic hydrophilic group component), and 117 g of high boiling point solvent B were charged at 80 ° C. The mixture was heated and mixed for 2 hours to cause urethanization reaction. Then, it stood to cool and maintained at 50 degreeC. 86.6 g of blocking agent was placed in a dropping funnel and added dropwise to this reaction over 1 hour. Subsequently, the reaction was terminated at 65 ° C. for 1 hour. The NCO content at this time was measured and confirmed to be 0.1 wt% or less.

Subsequently, 164 g of polyol A, 1.6 g of low molecular glycol, and 10.8 g of an anionic hydrophilic group component were added to the obtained blocked isocyanate intermediate, and the mixture was stirred and dissolved at 80 ° C. for 1 hour. After cooling to 70 ° C., 58.0 g of isophorone diisocyanate was added thereto, and the mixture was stirred at 80 ° C. for 4 hours to be reacted. After confirming that the equivalent of the hydroxyl group and the isocyanate group had reacted, the mixture was allowed to cool to 65 ° C., and 11.7 g of polyisocyanate A was added. After stirring for about 30 minutes, 8.2 g of a neutralizing agent was added, and the mixture was continuously stirred for about 30 minutes and maintained at 55 ° C.
Into this mixed solution, 518 g of water at normal temperature was dropped and dispersed at a stirring speed of 250 rpm for 2 minutes. 30 minutes after the dispersion, 30 g of a normal temperature triethylamine aqueous solution prepared in advance was added dropwise. Thereafter, high-speed stirring was maintained for 1 hour to obtain a milky white target product. Furthermore, it returned to the normal stirring speed (about 100 rpm), and stirred at 40 degreeC for 3 hours. Furthermore, 4.5 g of chain extender diethylenetriamine was added.
It was confirmed by FT-IR that there was no residual NCO assigned peak. As a result, the non-volatile content of the target product was 43%, the viscosity was 30 mPa · s (25 ° C.), and the average dispersed particle size was 256 nm. The results of the above production examples are shown in Table 1. Similarly, other compositions were made and listed in Table 1.

(Production of aqueous polyurethane resin emulsion coating composition)
Aqueous polyurethane dispersion A (manufactured by Nippon Polyurethane Industry Co., Ltd., polycarbonate-based non-yellowing type; viscosity 60 mPa · s (25 ° C.), non-volatile content 35 wt%, dispersed particle size 70 nm) 100 g and each emulsion listed in Table 1. And 0.15 g of a leveling agent (manufactured by Polyflow KL • 280, Kyoei Chemical Co., Ltd.) were mixed with a mixer at room temperature to obtain a coating composition.

[Coating agent evaluation test]
A steel plate ([SPEC-SB Co., Ltd., SPCC-SB) was coated with an applicator on 100 μm / wet, dried at room temperature for 5 minutes, and then heated at 100 to 200 ° C. with a temperature gradient drying apparatus (Gardner / gradient-even). For 5 minutes and 15 minutes.
(Observation of appearance) The appearance of the film dried and baked at each temperature shown in Table 2 was visually observed and evaluated for appearance such as having tack, matte, clear and rough.
(MEK rubbing test) In the coating film dried and baked at each temperature shown in Table 2, the absorbent cotton lightly dipped in methyl ethyl ketone MEK was reciprocated on the coating film, and the number of reciprocations until the coating film was scratched or peeled off was measured. It was measured.
(Alkali Resistance Test) A 5% NaOH aqueous solution was dropped on the coating film dried and baked at each temperature shown in Table 2 and allowed to stand at room temperature for 6 hours, and then the appearance of the coating film was visually observed and evaluated.
(Acid Resistance Test) 0.5N hydrochloric acid was dropped onto a coating film dried and baked at each temperature shown in Table 2 at room temperature and allowed to stand for 6 hours, and then the appearance of the coating film was visually observed and evaluated.
The results of the above [Evaluation of coating materials] are shown in Table 2.

[Evaluation test as a surface treatment agent]
The surface treatment agent was applied to a slate plate at 100 μm · wet with an applicator, dried at room temperature for 5 minutes, and then dried at 130 ° C. for 15 minutes.
Each of the impregnation property and adhesion property of the surface treatment agent, the blocking property immediately after drying, and the water resistance (50 ° C., 1 week immersion) was evaluated by appearance, and the results are shown in Table 3.

[Consideration of results of Examples and Comparative Examples]
In Table 1, “Comparison Intermediate A-1: Emulsion not having polyurethane resin (shell component) obtained by neutralizing a carboxyl group-containing isocyanate group-terminated urethane prepolymer and extending the chain Comparative Intermediate A-2: Block Emulsion having no polyisocyanate component (core component) Comparative composition A: Simple mixture of comparative intermediate A-1 and comparative intermediate A-2 Comparative composition B: Emulsion of prior invention without using polymeric MDI is there.
By contrasting each Example and each Comparative Example in Table 1, the block isocyanate-containing emulsion composition (Example Compositions A and B) of the present invention has a good liquid appearance even after 1 week at 50 ° C. and water dispersibility. In Comparative Composition A (cold blend that does not produce a core / shell in the same reaction system), a precipitate is formed, and Comparative Intermediate A-1 does not have a shell portion. Two layers of separation occur, each lacking water dispersibility because the average particle size of the emulsion is not micro.
In Table 2, performances such as appearance, MEK rubbing (organic solvent resistance), and chemical resistance as a coating film are well expressed in Examples 1 to 3 corresponding to the aqueous one-component coating composition of the present invention. ing. In Example 2, the average particle size of the emulsion is the smallest compared to Examples 1 and 3, so the appearance is clear and not matte. In Example 3, the drying time is slightly shorter (5 minutes), so the organic solvent resistance is , 2 (drying time 15 minutes) is slightly lower, but quick drying performance is apparent.

Comparative Example 1 uses Comparative Composition A (cold blend emulsion that does not produce a core and shell in the same reaction system), so that coating film cracking occurs even when applied, and coating film performance cannot be measured. It cannot be used as a paint.
Since Comparative Examples 2 and 3 use Comparative Composition B (emulsion according to the invention of the prior application that does not use polymeric MDI), performances such as MEK rubbing and chemical resistance are somewhat inferior to those of the present invention. Rather, it should be said that the emulsion of the present invention is more excellent than the emulsion of the invention of the prior application having various performances.

Further, considering the performance as a surface treatment agent in Table 3, in Examples 1 and 2 of the examples in which the emulsion of the present invention was applied to the surface treatment agent, the impregnation property and adhesion property of the surface treatment agent, blocking property, and water resistance Is excellent.
On the other hand, since Comparative Example 1 uses Comparative Composition A (cold blend emulsion that does not produce a core and shell in the same reaction system), all the performances are poor, and Comparative Example 2 shows Comparative Composition B ( Since the emulsion of the invention of the prior application that does not use polymeric MDI is used, the performance is slightly inferior. Rather, it should be said that the emulsion of the present invention is more excellent than the emulsion of the invention of the prior application having various performances.

From the comparison and discussion of the data results of each of the above Examples and Comparative Examples, and further considering the specificity of the micro particle size in the core-shell structure of the present invention, It can be said that the significance is demonstrated and it is clear that the present invention has a remarkable superiority as compared with the prior art.
Further, in the emulsion of the present invention, the chemical resistance of the coating film as a coating material is maintained while maintaining the various performances compared to the prior application invention which is excellent in various performances by pushing mainly the polymeric MDI. Further improvements in physical properties such as (organic solvent resistance, alkali resistance and acid resistance), and improved impregnation, adhesion and water resistance to the porous inorganic base material. Since the present invention is very useful as a (primer), the present invention is an invention different from the invention of the prior application, and an invention that exhibits further new and remarkable effects as compared with the invention of the prior application. It can be said that it has been clarified.

Industrial application fields

In the present invention, in the blocked isocyanate-containing emulsion composition, since the emulsion particles have a fine core / shell structure, the emulsion particle size distribution is reduced, and thus (i) a uniform emulsion free of impurities, and (ii) Water dispersibility and storage stability of emulsion above room temperature are sufficiently improved. (Iii) Various coating performances such as coating strength, coating uniformity and appearance appearing near the dissociation temperature of the block can be improved. (Iv) Impregnation, adhesion and water resistance to a porous inorganic base material are improved, and it is industrially very useful as a water-based paint or a base treatment agent (primer) which does not use an organic solvent.

Claims (11)

Polymeric MDI (a1) and nonionic polar group-containing polymer polyol (a2) are reacted, and the isocyanate group is blocked with a blocking agent (C) to produce a blocked polyisocyanate component (A). And reacting the organic polyisocyanate (b1) with the polymer polyol (b2) and the carboxyl group-containing anionic low-molecular glycol (b3) to produce a carboxyl group-containing isocyanate group-terminated urethane prepolymer (B). After neutralizing the carboxyl group of the product with a neutralizing agent (D), the reaction mixture was emulsified in water and subjected to a chain extension reaction with a chain extender (E) to produce a highly crosslinked polyurethane resin. A blocked isocyanate-containing emulsion composition. 2. The blocked isocyanate-containing composition according to claim 1, wherein the block polyisocyanate component (A) has a core-shell structure in which a core portion is formed and a highly crosslinked polyurethane resin forms a shell portion. Emulsion composition. 3. The blocked isocyanate-containing composition according to claim 1, wherein the emulsion has a water-dispersed particle size distribution of 50 to 400 nm and a core / shell weight ratio of 50/50 to 70/30. Emulsion composition. The block isocyanate-containing emulsion composition according to any one of claims 1 to 3, wherein the polymer polyol (b2) has a carbonate skeleton or a phthalate skeleton. The blocked isocyanate-containing emulsion composition according to any one of claims 1 to 4, wherein the neutralizing agent (D) is an amine compound, and the chain extender (E) is a polyamine compound. The blocked isocyanate-containing emulsion composition according to any one of claims 1 to 5, wherein the emulsion composition is an aqueous one-component baking type emulsion. Polymeric MDI (a1) and nonionic polar group-containing polymer polyol (a2) are reacted, and the isocyanate group is blocked with a blocking agent (C) to produce a blocked polyisocyanate component (A). And reacting the organic polyisocyanate (b1) with the polymer polyol (b2) and the carboxyl group-containing anionic low-molecular glycol (b3) to produce a carboxyl group-containing isocyanate group-terminated urethane prepolymer (B). After neutralizing the carboxyl group of the product with a neutralizing agent (D), the reaction mixture is emulsified in water and subjected to chain extension reaction with polyamine (E) to produce a highly crosslinked polyurethane resin, Production of a blocked isocyanate-containing emulsion composition according to any one of claims 1 to 6. Law. An aqueous ground treatment agent for a porous substrate, comprising the blocked isocyanate-containing emulsion composition according to any one of claims 1 to 6. An aqueous ground treatment for a porous substrate, characterized in that the blocked isocyanate-containing emulsion composition according to any one of claims 1 to 6 is used as a curing agent, and a polyurethane resin is contained as a main agent. An aqueous one-part coating composition comprising the blocked isocyanate-containing emulsion composition according to any one of claims 1 to 6 as a curing agent and a polyurethane resin as a main component. An aqueous one-component or two-component composition comprising a block isocyanate-containing emulsion composition according to any one of claims 1 to 5 as a curing agent, and a polyurethane resin as a main agent and a coating additive. Liquid baking type coating composition.

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