JP5557975B2 - Polyisocyanate composition - Google Patents

Description

  The present invention relates to a polyisocyanate composition comprising a polyisocyanate compound obtained from an aliphatic or alicyclic diisocyanate and a special silane coupling agent.

  A coating film obtained from a two-component polyurethane composition using a polyisocyanate composition obtained from an aliphatic or alicyclic diisocyanate as a curing agent has excellent performance such as weather resistance, chemical resistance, and abrasion resistance. Are widely used as paints, inks and adhesives. In recent years, global environmental problems have become highly conscious, and an aqueous two-component polyurethane composition that does not use an organic solvent or reduces the amount of use has been proposed. However, in the case of an aqueous two-component polyurethane composition, due to the composition of the composition, compared to a solvent-based two-component polyurethane composition, there are many cases where the substrate adhesion is less likely to be exhibited, and the substrate adhesion is improved. There is a need for polyisocyanate compositions that can be used.

  As a method for producing an aqueous two-component polyurethane composition, Patent Document 1 proposes an aqueous two-component polyurethane composition comprising an aqueous polyol having an emulsifying power and an isocyanate compound. Patent Documents 2 and 3 propose a polyisocyanate compound having water dispersibility and an aqueous two-component polyurethane composition using the same. However, as described above, coating films obtained from these aqueous two-component polyurethane compositions are less likely to exhibit substrate adhesion as compared with solvent-based two-component polyurethane compositions. Patent Document 4 proposes a polyisocyanate composition containing a silane coupling agent that does not contain active hydrogen. This is intended to improve the dispersibility in water, and also has a silane having an isocyanate group. No mention is made of coupling agents. Patent Document 5 proposes a polyisocyanate composition containing a silane coupling agent having a mercapto group and an alkoxysilane compound, which is aimed at improving the stain resistance.

Japanese Patent Laid-Open No. 2-105879 JP-A-5-222150 JP-A-9-328654 JP 2000-198920 A JP 2005-263839 A

  An object of this invention is to provide the polyisocyanate composition used as a hardening | curing agent of the two-component polyurethane composition excellent in base-material adhesiveness.

The present inventors have repeatedly studied to solve the above problems, and a polyisocyanate composition containing a polyisocyanate compound obtained from an aliphatic or alicyclic diisocyanate and a specific silane coupling agent is an aqueous two-component solution. It has been found that the above-mentioned problems can be achieved by using it as a curing agent for a type polyurethane composition, and the present invention has been completed.
That is, the present invention is as follows.
(1) (A) Polyisocyanate compound having uretdione structure, isocyanurate structure or polyisocyanate compound having iminooxadiazine dione structure derived from at least one diisocyanate selected from aliphatic diisocyanate and alicyclic diisocyanate , Polyisocyanate compound having biuret structure, polyisocyanate compound having oxadiazine trione structure, polyisocyanate compound having plural urethane groups, polyisocyanate compound having allophanate structure, polyisocyanate compound having acylurea group, having urea structure At least one polyisocyanate compound selected from polyisocyanate compounds , said polyisocyanate compound and alkoxypolyamide A polyisocyanate containing a polyisocyanate compound containing a reaction product with ruylene glycol and (B) a silane coupling agent having an isocyanate group, and used as a curing agent for an aqueous two-component polyurethane composition Composition.
(2) Further, (C) tetraalkyloxysilane represented by the following chemical formula (1), a condensate of tetraalkoxysilane, a tetraalkoxysilane or a part of the alkoxy group of the tetraalkoxysilane condensate is partially substituted with polyalkylene glycol mono The polyisocyanate composition according to (1) above, comprising at least one alkoxysilane compound selected from the group consisting of alkyl ethers and tetraalkoxysilane compounds substituted with polyalkylene glycol monoaryl ethers.

(In the formula, R represents the same or different alkyl group having 1 to 10 carbon atoms or an aryl group.)

When the polyisocyanate composition of the present invention is used as a curing agent for an aqueous two-component polyurethane composition, the aqueous two-component polyurethane composition has excellent adhesion to substrates such as metals, plastics, and old paint films. It has the feature of being. When immersed in water, blisters (coating blisters) are less likely to occur.
Furthermore, when the polyisocyanate composition of the present invention containing a silicate compound is used as a curing agent for an aqueous two-component polyurethane composition used for exterior use, it also has a feature that it is difficult to get dirt such as rain stripe contamination.

The present invention will be specifically described below.
In the present invention, at least one isocyanate compound selected from aliphatic diisocyanate and alicyclic diisocyanate is used.
An aliphatic diisocyanate is a compound having only an aliphatic group in the molecule. On the other hand, alicyclic diisocyanate is a compound having a cyclic aliphatic group in the molecule. Use of an aliphatic diisocyanate is more preferable because the resulting polyisocyanate compound has a low viscosity. Examples of the aliphatic diisocyanate include 1,4-diisocyanatobutane, 1,5-diisocyanatopentane, ethyl (2,6-diisocyanato) hexanoate, 1,6-diisocyanatohexane (hereinafter referred to as HDI), 1 , 9-diisocyanatononane, 1,12-diisocyanatododecane, 2,2,4- or 2,4,4-trimethyl-1,6-diisocyanatohexane and the like. Examples of the alicyclic diisocyanate include 1,3- or 1,4-bis (isocyanatomethyl) cyclohexane (hereinafter referred to as hydrogenated XDI), 1,3- or 1,4-diisocyanatocyclohexane, 3,5. , 5-trimethyl 1-isocyanato-3- (isocyanatomethyl) cyclohexane (hereinafter referred to as IPDI), 4-4′-diisocyanato-dicyclohexylmethane (hereinafter referred to as hydrogenated MDI), 2,5- or 2,6-diisocyanate And natomethylnorbornane. Among these, HDI, IPDI, hydrogenated XDI, and hydrogenated MDI are preferable because they are easily available industrially. Among them, HDI is most preferable because it has excellent weather resistance and flexibility of the coating film. Hereinafter, aliphatic diisocyanate and alicyclic diisocyanate are collectively referred to as diisocyanate.

  The polyisocyanate compound derived from the diisocyanate is a polyisocyanate compound having a uretdione structure obtained by cyclizing and dimerizing two isocyanate groups, and an isocyanurate structure obtained by cyclizing and trimerizing three isocyanate groups. Or a polyisocyanate compound having an iminooxadiazinedione structure, a polyisocyanate compound having a biuret structure obtained by reacting three isocyanate groups and one water molecule, two isocyanate groups and one molecule of carbon dioxide A polyisocyanate compound having an oxadiazine trione structure obtained by reacting a polyisocyanate, a polyisocyanate compound having a plurality of urethane groups obtained by reacting one isocyanate group and one hydroxyl group, and two isocyanates A polyisocyanate compound having an allophanate structure obtained by reacting a group with one hydroxyl group, a polyisocyanate compound having an acylurea group obtained by reacting one isocyanate group and one carboxyl group, one isocyanate group and 1 And polyisocyanate compounds having a urea structure obtained by reacting two primary or secondary amines. These may be used alone or in combination of two or more.

  Among the polyisocyanate compounds, those having a structure such as biuret, isocyanurate, urethane, uretdione, and allophanate in the molecule are preferable. Those having a biuret structure are excellent in adhesiveness, those having an isocyanurate structure are excellent in weather resistance, and those having a urethane structure using an alcohol compound having a long side chain are excellent in elasticity and extensibility. In addition, those having a uretdione structure are characterized by low viscosity. Those having an allophanate structure have the characteristic of imparting the performance (polarity, Tg, etc.) of a compound having an incorporated hydroxyl group in addition to the characteristic of low viscosity.

  From the viewpoint of water dispersibility, the polyisocyanate compound used in the present invention is preferably a water-dispersible polyisocyanate compound modified with a nonionic and / or ionic surfactant. As such a polyisocyanate compound, any hydrophilic group introduced by a conventionally known method can be used without particular limitation, for example, a reaction product of an alkoxy polyalkylene glycol and a polyisocyanate compound, A reaction product of a vinyl polymer containing a nonionic group having isocyanate activity and an isocyanate reactive group (such as a hydroxyl group) and a polyisocyanate compound, a reaction product obtained by reacting a dialkanolamine, A polyisocyanate compound containing a reaction product of a polyisocyanate compound and a compound having a sulfonic acid group and an isocyanate reactive group such as an isethionic acid amine salt can be given. Among these, a polyisocyanate compound containing a reaction product of an alkoxy polyalkylene glycol and a polyisocyanate compound is particularly preferable because of its excellent water dispersibility.

  The introduction amount of the hydrophilic group in the polyisocyanate compound is preferably 1 to 80% by mass. The lower limit of the introduction amount is more preferably 2% by mass, more preferably 3% by mass, and still more preferably 4% by mass. The upper limit is more preferably 60% by mass, still more preferably 40% by mass, and still more preferably 25% by mass. It is preferably 1% by mass or more because of its high water dispersibility. The curability when used as a curing agent for an aqueous two-component polyurethane composition at 80% by mass or less is preferable.

The reaction product of a polyisocyanate compound and an alkoxy polyalkylene glycol that can be suitably used as the polyisocyanate is obtained by combining the polyisocyanate compound (B) and the alkoxy polyalkylene glycol with an isocyanate. It is appropriate to carry out the reaction so that the equivalent ratio of group / hydroxyl group is preferably 1.1 to 50. The lower limit of the equivalent ratio of isocyanate group / hydroxyl group is more preferably 2, more preferably 3, and still more preferably 4. The upper limit is more preferably 30, and even more preferably 25. When the equivalent ratio is in the range of 1.1 to 50, the dispersibility in water and the water resistance of the aqueous two-component polyurethane composition are sufficient. The alkoxy polyalkylene glycol is represented by the following chemical formula (2).
^{R 1 O- (R 2 O)} n-H (2)
(R ¹ preferably represents an alkyl group having 2 to 30 carbon atoms or an aryl group, and R ² preferably represents an alkylene group having 1 to 5 carbon atoms. N is preferably an integer of 3 to 50. (The lower limit of n is more preferably 4, more preferably 4.5, still more preferably 5.0. The upper limit is more preferably 35, still more preferably 25).
When n is 3 to 50, water dispersibility is sufficient, and crystallinity is low and easy to handle.

  Examples of such alkoxypolyalkylene glycols include polymethylene glycol monomethyl ether, polyethylene glycol monomethyl ether, polyethylene glycol monoethyl ether, polyethylene glycol monopropyl ether, polyethylene glycol monolauryl ether, polyethylene glycol phenyl ether. , Polyethylene glycol alkyl phenyl ether, polyethylene glycol phenyl phenyl ether, polyethylene glycol styryl phenyl ether, polyethylene glycol naphthyl ether, polyoxyethylene-oxypropylene (random and / or block) glycol monomethyl ether, polyoxyethylene-oxytetramethylene (random) And / or block ) Glycol polybutylene glycol monomethyl ether, (mono-penta) styrenated phenyl group, mono (or di, tri) styryl-methyl-phenyl group, tribenzylphenyl group, β-naphthyl group, etc. Nonionic surfactants having groups contained above can be exemplified.

  The molecular weight of these alkoxypolyalkylene glycols is preferably in the range of 150 to 5,000. The lower limit of the molecular weight is more preferably 194, more preferably 216, and still more preferably 238. The upper limit is more preferably 4000, even more preferably 3000, and still more preferably 2500. When the molecular weight is in the range of 150 to 5000, the water dispersibility is sufficient and the crystallinity is low and easy to handle.

  The polyisocyanate composition having a hydrophilic group used in the present invention is more preferably a polyisocyanate having water dispersibility. Water dispersibility refers to the ability of a polyisocyanate composition to be dispersed in water so that it is O / W type. Add polyisocyanate to water and mechanically stir using a stick or hand mixer. Is the ability to disperse in water.

The polyisocyanate compound used in the present invention may be mixed with an ionic surfactant containing substantially no water. By mixing an ionic surfactant, when dispersed in water, a double protective film is formed on the surface of the polyisocyanate oil droplets, and the dispersion stability of the polyisocyanate oil droplets is remarkably improved. Intrusion into the polyisocyanate oil droplets is prevented. This significantly extends the pot life of the polyurethane composition, reduces the particle size of the polyisocyanate oil droplets, and can further improve the water resistance.
The isocyanate group content of the polyisocyanate compound used in the present invention is preferably 5 to 25% by mass. The lower limit of the isocyanate group content is more preferably 8% by mass, and most preferably 10% by mass. The upper limit is more preferably 24%, and most preferably 23%. In the range of 5 to 25% by mass, the curing speed when used as a curing agent for an aqueous two-component polyurethane composition, or the toughness of a coating such as a coating film can be achieved.

  The number average molecular weight of the polyisocyanate compound is preferably 350 to 10,000. The lower limit of the number average molecular weight is more preferably 400, and most preferably 450. The upper limit is more preferably 7000, and still more preferably 5000. In the range of 350 to 10,000, the crosslinkability when used as a curing agent for an aqueous two-component polyurethane composition is sufficient, and the viscosity is easy to handle.

  The viscosity of the polyisocyanate composition of the present invention is preferably 10 to 40,000 mPa · s (25 ° C.). The lower limit of the viscosity is more preferably 20 mPa.s. s, more preferably 40 mPa.s. s. The upper limit is more preferably 20000 mPa.s. s, more preferably 10,000 mPa.s. s, most preferably 5000 mPa.s. s. If it is the range of 10-20000 mPa * s, the dispersibility to water is sufficient and it does not contain a large amount of diisocyanate and a solvent with low bridge | crosslinking capability.

  The polyisocyanate composition of the present invention can be used with an organic solvent added. The polyisocyanate mixed with the organic solvent has a feature that the viscosity is lowered, so that the water dispersibility is improved, the residual ratio of isocyanate groups at the time of water dispersion is increased, and the pot life is prolonged. In this case, it is necessary that the organic solvent does not have a functional group that reacts with an isocyanate group. The organic solvent must be compatible with the self-emulsifiable polyisocyanate composition of the present invention.

  Examples of the organic solvent added to the polyisocyanate composition of the present invention include ethyl acetate, propyl acetate, isopropyl acetate, butyl acetate, isobutyl acetate, pentyl acetate, methoxypropyl acetate, 3-methoxybutyl acetate, and 2-ethylbutyl acetate. Ester compounds such as 2-ethylhexyl acetate, cyclohexyl acetate, methyl propionate, butyl propionate, butyl butyrate, dioctyl adipate, diisopropyl glutarate, ether compounds such as diisopropyl ether, dibutyl ether, dioxane, diethoxyethane, 2-pentanone, 3-pentanone, 2-hexanone, methyl isobutyl ketone, 2-heptanone, 4-heptanone, diisobutyl ketone, isophorone, cyclohexanone, methylcyclohexane Ketone compounds such as Sanone, aromatic compounds such as benzene, toluene, xylene, ethylbenzene, butylbenzene, and p-cymene, and polyethylene glycol dialkyl ethers such as diethylene glycol dimethyl ether, diethylene glycol diethyl ether, triethylene glycol dimethyl ether, and diethylene glycol dibutyl ether And polyethylene glycol dicarboxylate compounds such as diethylene glycol diacetate.

  The amount of the organic solvent added to the polyisocyanate composition is preferably 1 to 70% by mass with respect to the polyisocyanate composition (including the organic solvent). The lower limit of the addition amount is more preferably 3% by mass, and still more preferably 5% by mass. The upper limit of the addition amount is more preferably 60% by mass, and still more preferably 50% by mass. When it is in the range of 1 to 70% by mass, the polyisocyanate composition is preferable without lowering the viscosity of the polyisocyanate composition and extending the pot life, and without increasing the amount of organic solvent.

The polyisocyanate composition of the present invention contains (B) a silane coupling agent having an isocyanate group.
(B) Content of the silane coupling agent which has an isocyanate group, Preferably it is 0.01-20 mass parts with respect to 100 mass parts of polyisocyanate compounds. The lower limit of the content of the silane coupling agent is more preferably 0.03 parts by mass, still more preferably 0.05 parts by mass, and most preferably 0.1 parts by mass. The upper limit of the content is more preferably 10 parts by mass, more preferably 7.5 parts by mass, and most preferably 5 parts by mass. In the range of 0.01 to 20 parts by mass, sufficient substrate adhesion can be exhibited.

(B) The silane coupling agent having an isocyanate group is not particularly limited as long as it has one or more isocyanate groups and one or more hydrolyzable silyl groups in the molecule. The compound which has a structure represented by Chemical formula (3) is mentioned.
(OCN-R1) _n -Si- (R2) _4-n (3)
(In the formula, n is an integer of 1 to 3, R1 is an aliphatic hydrocarbon group which may have a substituent having 1 to 16 carbon atoms, or an aryl which may have a substituent having 6 to 10 carbon atoms. A cycloalkyl group which may have a substituent having 5 to 6 carbon atoms, n R1s may be the same or different, R2 is an alkoxy group having 1 to 8 carbon atoms, (Selected from an acetoxy group and a hydroxyl group. 4-n R2s may be the same or different.)
In particular, the (B) silane coupling agent having an isocyanate group is preferably a compound in which n = 1 in the chemical formula (3), and more specifically, γ-isocyanatopropyltrimethoxysilane, γ-isocyanatopropyltriethoxy. Silane etc. are mentioned.

  The polyisocyanate composition of the present invention is preferably at least one selected from tetraalkoxysilane having a structure represented by the following chemical formula (1), a condensate of tetraalkoxysilane, and a tetraalkoxysilane or a derivative of the condensate thereof. Silicate compounds can be included.

R in a formula is the same or different C1-C10 alkyl group or an aryl group. The upper limit of the carbon number is preferably 8, more preferably 6, still more preferably 4. R is preferably an alkyl group.
When R is an alkyl group, it may be either linear or branched, but is more preferably linear.
When R is an aryl group, it may be monocyclic or polycyclic, but is preferably monocyclic.
By containing a silicate compound, when a coating film is prepared as an aqueous two-component polyurethane composition, the coating film surface becomes hydrophilic and rain-stain stain resistance is exhibited.

  When a tetraalkoxysilane condensate is used, the average degree of condensation is 1.1-100. The lower limit of the average degree of condensation is preferably 2, more preferably 4, and still more preferably 6. The upper limit is preferably 60, more preferably 40, and even more preferably 20. When the average degree of condensation is in the range of 1.1 to 100 and the coating film is prepared, the hydrophilicity of the coating film surface is sufficiently high. The tetraalkoxysilane condensate can be produced by a known method. When using a tetraalkoxysilane condensate as a water-based two-component polyurethane composition, when a coating film is prepared, the silicate compound is more likely to be coordinated on the coating surface, and the surface tends to be hydrophilic due to hydrolysis. Is even more preferable.

  Examples of the silicate compound include tetramethoxysilane, tetraethoxysilane, tetra-n-propoxysilane, tetraisopropoxysilane, tetra-n-butoxysilane, tetraisobutoxysilane, tetra-tert-butoxysilane, dimethoxydiethoxysilane, Examples thereof include tetraphenoxysilane and condensates thereof. Among these, the condensate of tetramethoxysilane and the condensate of tetraethoxysilane are preferable because when the coating film is prepared as an aqueous two-component polyurethane composition, the coating film surface tends to be hydrophilic. In particular, a condensate of tetramethoxysilane is even more preferable because the hydrolysis rate is fast and the surface becomes hydrophilic quickly.

  Furthermore, tetraalkoxysilane in which two or more types of alkoxyl groups having different carbon numbers are mixed and a condensate thereof can be used as the silicate compound. This is a method using tetramethoxysilane or a compound in which 5 to 50 mol% of methoxy group or ethoxy group of tetraethoxysilane is substituted with an alkoxyl group having 3 to 10 carbon atoms. The ratio of substituting the methoxy group and the ethoxy group with an alkoxyl group having 3 to 10 carbon atoms is more preferably 8 to 40 mol%, still more preferably 12 to 35 mol%. The substituted alkoxyl group is preferably a butoxy group, a pentyloxy group, a hexyloxy group, and an octyloxy group, and more preferably an n-butyl group, an isobutyl group, a tert-butyl group, an n-hexyl group, and an n- An octyl group and a 2-ethyl-1-hexyl group.

Tetraalkoxysilane or a derivative of a condensate thereof refers to a silicate compound in which a part of an alkoxy group is substituted with, for example, polyalkylene glycol monoalkyl ether or polyalkylene glycol monoaryl ether. When a coating film is formed as a water-based two-component polyurethane composition, a tetraalkoxysilane substituted by a highly polar group such as polyalkylene glycol monoalkyl ether or polyalkylene glycol monoaryl ether, or a derivative of a condensate thereof, Dispersion in water is easy, and it is more preferable.
In the polyisocyanate composition of the present invention containing a silicate compound, the mass ratio of the polyisocyanate compound and the silicate compound is preferably 5/95 to 95/5. The lower limit of the mass ratio of the polyisocyanate compound and the silicate compound is more preferably 10/90, still more preferably 20/80, and most preferably 30/70. The upper limit is more preferably 90/10, even more preferably 80/20, and most preferably 70/30.

The polyisocyanate composition of the present invention can be used as a curing agent for an aqueous two-component polyurethane composition. The aqueous two-component polyurethane composition is composed of a main agent composition containing an aqueous polyol and a curing agent composition containing the polyisocyanate composition of the present invention.
The aqueous polyol used in the present invention includes all those expressed as latex, emulsion, and water-soluble resin containing a hydroxyl group. For example, polyvinylidene chloride copolymer, polyvinyl chloride copolymer, vinyl acetate copolymer, water-soluble acrylic resin, water-soluble polyester resin, urethane dispersion, acrylic emulsion, fluorine copolymer emulsion, styrene-butadiene copolymer Latex, acrylonitrile butadiene copolymer, rubber latex, polybutadiene copolymer, urethane acrylic emulsion, etc., or copolymers or mixtures thereof.

  The hydroxyl value of the aqueous polyol used in the present invention is preferably 1 to 300 mgKOH / g. The lower limit of the hydroxyl value is more preferably 5 mgKOH / g, still more preferably 10 mgKOH / g. The upper limit is more preferably 200 mgKOH / g, still more preferably 150 mgKOH / g. If it is the range of 1-300 mgKOH / g, the crosslinking point at the time of setting it as an aqueous two-pack type polyurethane composition will be enough, and a flexible and tough aqueous two-pack type polyurethane composition (cured material) can be obtained.

The aqueous polyol used in the present invention is more preferably expressed as latex, emulsion, or dispersion. These are characterized by excellent operability and water resistance. Among them, acrylic emulsion, fluorocopolymer emulsion, urethane dispersion, or these copolymers are extremely excellent in weather resistance, gloss, and toughness when a coating film is prepared as an aqueous two-component polyurethane composition. Is preferable.
The particle diameter in the case of using an aqueous polyol expressed as latex, emulsion, or dispersion is preferably 5 nm (nanometers) to 1.0 μm. The lower limit of the particle diameter is more preferably 10 nm, still more preferably 40 nm. The upper limit is more preferably 500 nm, and still more preferably 300 nm. If it is the range of 5 nm-1.0 micrometer, the gloss when a coating film is created as an aqueous two-pack type polyurethane composition is high, and water resistance is also excellent. Moreover, the stability as latex, emulsion, and dispersion is sufficient.

  When the polyisocyanate composition of the present invention is used as a curing agent for an aqueous two-component polyurethane composition, the isocyanate group / hydroxyl group equivalent ratio of the polyisocyanate composition and the aqueous emulsion is preferably 0.3 to 5.0. . The lower limit of the equivalent ratio is more preferably 0.5, and still more preferably 0.6. The upper limit is more preferably 3.0, and even more preferably 2.5. If the equivalent ratio is in the range of 0.3 to 5.0, the crosslinking point when the coating film is prepared as the aqueous two-component polyurethane composition is sufficient, and the flexibility and toughness are sufficient.

The polyisocyanate composition of the present invention or the main agent composition used in the present invention includes, for example, a thickener, a leveling agent, a thixotrope as various known and commonly used paint additives depending on the use and method of use. Agent, antifoaming agent, freezing stabilizer, matting agent, crosslinking reaction catalyst, anti-skinning agent, dispersant, wetting agent, light stabilizer, antioxidant, UV absorber, filler, plasticizer, lubricant Additives such as reducing agents, antiseptics, antifungal agents, deodorants, anti-yellowing agents, antistatic agents, or charge control agents are appropriately selected within a range that does not interfere with the effects of the present invention. Can be used.
For the main agent composition used in the present invention, if necessary, for imparting various functions such as coloring, concealment, coating film hardness, drying properties, substrate adhesion, UV blocking and design properties. In addition, known and commonly used pigments can be used.

When the polyisocyanate composition of the present invention is used as a curing agent for an aqueous two-component polyurethane composition, the aqueous two-component polyurethane composition has excellent adhesion to substrates such as metals, plastics, and old paint films. It has the feature of being. When immersed in water, blisters (coating blisters) are less likely to occur.
Furthermore, when the polyisocyanate composition of the present invention containing a silicate compound is used as a curing agent for an aqueous two-component polyurethane composition used for exterior use, it also has a feature that it is difficult to get dirt such as rain stripe contamination.
Therefore, the aqueous two-component polyurethane composition using the polyisocyanate composition of the present invention can be used as a raw material for paints, inks, adhesives, inks, casting materials, elastomers, foams, and plastic materials. Among them, it can be used for paints for buildings, paints for heavy anticorrosion, paints for automobiles, paints for home appliances, paints for information devices such as personal computers and mobile phones. It is particularly suitable for building exterior paints and heavy anticorrosion paints.

Examples are shown below. In the examples, “%” and “part” indicate “% by mass” and “part by mass”.
<Preparation of aqueous coating composition>
A predetermined amount of the polyisocyanate composition was added to the aqueous polyol, and the mixture was prepared by stirring at 600 rpm × 10 min.
<Isocyanate group content>
The isocyanate group content was determined by back titration with 1N hydrochloric acid after adding 10 ml toluene to about 2 g of the sample and neutralizing the isocyanate group with an excess of 2N amine (toluene solution).

<Viscosity>
The viscosity was measured at 25 ° C. with an E-type viscometer (manufactured by Tokimec Co., Ltd.).
A standard rotor (1 ° 34 ′ × R24) was used. The number of revolutions is as follows.
100 rpm (when less than 128 mPa · s)
50 rpm (in the case of 128 mPa · s to 256 mPa · s)
20 rpm (in the case of 256 mPa · s to 640 mPa · s)
10 rpm (from 640 mPa · s to 1280 mPa · s)
5 rpm (in the case of 1280 mPa · s to 2560 mPa · s)
2.5 rpm (in the case of 2560 mPa · s to 5120 mPa · s)

(Synthesis example 1 of aqueous polyol)
Prepare a reaction vessel equipped with a stirrer, reflux condenser, two dripping tanks, and a thermometer. The two dripping tanks are filled with a Y-shaped tube (100 mesh metal mesh is packed at the outlet of the Y-shaped tube. Filled with molecular sieves 3A (product name: manufactured by Wako Pure Chemical Industries, Ltd.) to the point where the liquid is mixed, the pre-emulsion liquid containing the radical polymerizable monomer and the hydrolyzable silane can be mixed gently. It was assembled so that it could flow into the reaction system via 600 parts of water, 5 parts of an anionic reactive surfactant containing an alkylene oxide group (product name: Aqualon KH-1025, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), the temperature was raised to 80 ° C. A 15% aqueous solution was added and stirred for 5 minutes.
Subsequently, 14 parts of methyl methacrylate, 400 parts of cyclohexyl methacrylate, 10 parts of n-butyl methacrylate, 250 parts of n-butyl acrylate, 18 parts of 2-hydroxyethyl methacrylate, 8 parts of methacrylic acid, Aqualon KH-1025 3 parts, 10 parts of alkyl sulfosuccinate surfactant (product name: Aerosol OT-75, manufactured by Nippon Cytec Industries Co., Ltd.), an anionic surfactant containing an alkylene oxide group (product name: Newcor 707SF, 14 parts of Nippon Emulsifier Co., Ltd.), 10 parts of a hindered amine light stabilizer (product name: TINUVIN123, Ciba Specialty Chemicals Co., Ltd.), 75 parts of a 2% aqueous solution of ammonium persulfate, and 400 parts of water are added and mixed. Made by mixing the liquid for 5 minutes with a homomixer 135 minutes of the pre-emulsified liquid and the mixed liquid consisting of 3 parts of γ-methacryloxypropyltrimethoxysilane, 40 parts of methyltrimethoxysilane and 12 parts of diphenyldimethoxysilane from the separate dropping tank through the Y-shaped tube. Overflowed. The pH during the silicone modification reaction was maintained at 4 or less. During the inflow, the temperature in the reaction vessel was kept at 80 ° C. After the inflow was completed, the temperature in the reaction vessel was raised to 80 ° C. and kept for 30 minutes.
Next, 159 parts methyl methacrylate, 60 parts n-butyl acrylate, 75 parts 2-hydroxyethyl methacrylate, 6 parts acrylic acid, 1 part dodecyl mercaptan, 3 parts Newcor 707SF, 2% aqueous solution of ammonium persulfate 35 And 200 parts of water were added, and a pre-emulsion prepared by mixing the mixed solution for 5 minutes with a homomixer was allowed to flow into the reaction vessel from the dropping tank over 90 minutes. During the inflow, the temperature in the reaction vessel was kept at 80 ° C. After the inflow was completed, the temperature in the reaction vessel was raised to 80 ° C. and maintained for 90 minutes.
After cooling to room temperature, the hydrogen ion concentration was measured and found to be pH 2.6. A 25% aqueous ammonia solution was added to adjust the pH to 8.5, followed by filtration through a 100 mesh wire net. The dry mass of the filtered aggregate was as little as 20 ppm with respect to the obtained solid content mass. The number average particle diameter of the obtained aqueous polyol was 120 nm, and the solid content was 43.2%.

(Synthesis Example 2 of aqueous polyol)
Prepare a reaction vessel equipped with a stirrer, reflux condenser, two dripping tanks, and a thermometer. The two dripping tanks are filled with a Y-shaped tube (100 mesh metal mesh is packed at the outlet of the Y-shaped tube. The molecular sieves 3A were filled up to the point where they were mixed, and adjusted so that the pre-emulsified liquid containing the radical polymerizable monomer and the hydrolyzable silane could be mixed gently.) It was assembled so that it could flow. 500 parts of water, 5 parts of Aqualon KH-1025, 17 parts of an anionic reactive surfactant containing an alkylene oxide group (product name: Adekaria Soap SR-1025, manufactured by Asahi Denka Kogyo Co., Ltd.) and a temperature of 80 parts After raising the temperature to 20 ° C., 20 parts of a 2% aqueous solution of ammonium persulfate was added and stirred for 5 minutes.
Subsequently, 20 parts of cyclohexyl methacrylate, 107 parts of n-butyl methacrylate, 150 parts of n-butyl acrylate, 20 parts of 2-hydroxyethyl methacrylate, 3 parts of acrylic acid, 8 parts of Aqualon KH-1025, ADEKA rear soap 14 parts of SR-1025, 30 parts of a 2% aqueous solution of ammonium persulfate and 120 parts of water were added, and a pre-emulsion prepared by mixing the mixture for 5 minutes with a homomixer, and γ-methacryloxypropyltrimethoxysilane 3 Part mixture, 30 parts of methyltrimethoxysilane, and 20 parts of diphenyldimethoxysilane were allowed to flow from separate dropping tanks over 105 minutes through the Y-shaped tube. The pH during the silicone modification reaction was maintained at 4 or less. During the inflow, the temperature in the reaction vessel was kept at 80 ° C. After the inflow was completed, the temperature in the reaction vessel was raised to 80 ° C. and kept for 30 minutes.
Next, 270 parts of methyl methacrylate, 100 parts of cyclohexyl methacrylate, 100 parts of n-butyl acrylate, 220 parts of 2-hydroxyethyl methacrylate, 10 parts of acrylic acid, 2.1 parts of dodecyl mercaptan, 11 parts of Aqualon KH-1025 20 parts of Adekaria soap SR-1025, 70 parts of a 2% aqueous solution of ammonium persulfate, and 450 parts of water were added, and the pre-emulsified liquid prepared by mixing the mixed solution for 5 minutes with a homomixer was put into a reaction vessel. It was made to flow in from a dripping tank over 210 minutes. During the inflow, the temperature in the reaction vessel was kept at 80 ° C. After the inflow was completed, the temperature in the reaction vessel was raised to 80 ° C. and maintained for 90 minutes.
After cooling to room temperature, the hydrogen ion concentration was measured and found to be pH 2.7. A 25% aqueous ammonia solution was added to adjust the pH to 8.5, followed by filtration through a 100 mesh wire net. The dry mass of the filtered aggregate was as little as 20 ppm with respect to the obtained solid content mass. The number average particle diameter of the obtained aqueous polyol was 125 nm, and the solid content was 45.1%.

(Preparation of pigment dispersion)
Dispersant: Pig. Disperser MD20
(Product name, manufactured by BASF Japan Ltd.) 5.35 parts Ammonia water 0.50 parts Propylene glycol 23.50 parts Water 147.50 parts Taipei CR-97 (trade name, manufactured by Ishihara Sangyo Co., Ltd.) 333.50 parts Foam: SN deformer 1310
(Trade name, manufactured by San Nopco Co., Ltd.) 2.85 parts The above-mentioned composition was dispersed in a tabletop sand mill for 20 minutes to obtain a pigment dispersion.

(Formulation example 1 of aqueous polyol composition)
Under stirring, CS-12 (trade name, 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate, Chisso Corporation) was added to 100 parts of the aqueous polyol obtained in Synthesis Example 1 of aqueous polyol. An aqueous polyol composition was obtained by adding 10 parts. (Formulation example 2 of aqueous polyol composition)
To 100 parts of the aqueous polyol obtained in Synthesis Example 2 of aqueous polyol, under stirring, 4 parts of CS-12, 4 parts of 50% aqueous solution of 2-butoxyethanol, New Coal 2399S (product name, manufactured by Nippon Emulsifier Co., Ltd., 3 parts of a 25% aqueous solution of HLB = 19.2), 57 parts of pigment dispersion, and 0.3 part of a 10% aqueous solution of Adecanol UH-438 (trade name, manufactured by Asahi Denka Kogyo Co., Ltd.) are added to obtain an aqueous polyol composition. Got.

(Synthesis example 1 of polyisocyanate compound)
Methoxypolyethylene glycol (MPG-130, ethylene oxide repeating unit = 9, manufactured by Nippon Emulsifier Co., Ltd.) and sodium dialkylsulfosuccinate (Newcol 290M, solid content 70%, manufactured by Nippon Emulsifier Co., Ltd.) in a solid content weight ratio of 3 1 and mixed to remove water and solvent by distillation under reduced pressure. The inside of a four-necked flask equipped with a stirrer, a thermometer, and a condenser tube was replaced with nitrogen, and 800 g of isocyanurate type polyisocyanate (Duranate TPA-100, manufactured by Asahi Kasei Chemicals Corporation) and methoxypolyethylene glycol obtained from the above 200 g of a mixture of sodium dialkylsulfosuccinate was mixed and subjected to urethanization reaction at 120 ° C. for 3 hours. The obtained hydrophilic polyisocyanate composition was a pale yellow liquid, the isocyanate group content was 16.5%, and the viscosity was 1800 mPa · s. The obtained polyisocyanate composition had dispersibility in water. This polyisocyanate compound is designated as a-1.

(Synthesis example 2 of polyisocyanate compound)
Methoxypolyethylene glycol (MPG-081, ethylene oxide repeating unit = 15, manufactured by Nippon Emulsifier Co., Ltd.) and sodium dialkylsulfosuccinate (Newcol 290M, solid content 70%, manufactured by Nippon Emulsifier Co., Ltd.) at a solid content weight ratio of 2 1 and mixed to remove water and solvent by distillation under reduced pressure. 1000 g of biuret type polyisocyanate (Duranate 24A-100, manufactured by Asahi Kasei Chemicals Co., Ltd.) and 300 g of the mixture of methoxypolyethylene glycol and sodium dialkylsulfosuccinate obtained above were mixed and subjected to urethanization reaction at 90 ° C. for 2 hours. The obtained hydrophilic polyisocyanate composition was a pale yellow liquid, the isocyanate group content was 16.5%, and the viscosity was 4500 mPa · s. The obtained polyisocyanate composition had dispersibility in water. This polyisocyanate compound is designated as a-2.

[Examples 1-7]
11.1 parts of propylene glycol monomethyl ether acetate (PMA), KBE9007 (trade name, γ-isocyanatopropyltriethoxy) with respect to 100 parts of polyisocyanate compound a-1 obtained in Synthesis Example 1 of polyisocyanate compound Silane, manufactured by Shin-Etsu Chemical Co., Ltd.) 0.1, 0.5, 1.0, 2.0, 2.5, 3.0, 5.0 parts with respect to a-1, and polyisocyanate composition b -1 to b-7 were obtained.
[Example 8]
To 100 parts of the hydrophilic polyisocyanate composition a-2 obtained in Synthesis Example 2 of a polyisocyanate compound, with stirring, a partial hydrolysis condensate of tetramethoxysilane (trade name: MKC silicate MS56, manufactured by Mitsubishi Chemical Corporation, 20 parts of average molecular weight = 1100-1300), 1 part of KBE-9007 (trade name, γ-isocyanatopropyltriethoxysilane, manufactured by Shin-Etsu Chemical Co., Ltd.), 40 parts of diethylene glycol dibutyl ether (DBDG) are added, and transparent Polyisocyanate composition b-8 was obtained.

[Comparative Example 1]
11.1 parts of propylene glycol monomethyl ether acetate (PMA) was added to 100 parts of the polyisocyanate compound a-1 obtained in Synthesis Example 1 of the polyisocyanate compound to obtain a polyisocyanate mixture c-1. .
[Comparative Example 2]
11.1 parts of propylene glycol monomethyl ether acetate (PMA), KBM503 (trade name, γ-methacryloxypropyltrimethoxy) with respect to 100 parts of polyisocyanate compound a-1 obtained in Synthesis Example 1 of polyisocyanate compound 1.0 part of Silane (manufactured by Shin-Etsu Chemical Co., Ltd.) was added to a-1 to obtain a polyisocyanate mixture c-2.

[Comparative Example 3]
11.1 parts of propylene glycol monomethyl ether acetate (PMA) and GF80 (trade name, 3-glycidoxypropyltri) with respect to 100 parts of polyisocyanate compound a-1 obtained in Synthesis Example 1 of polyisocyanate compound 1.0 part of methoxysilane, manufactured by Asahi Kasei Wacker Silicone Co., Ltd.) was added to a-1 to obtain a polyisocyanate mixture c-3.
[Comparative Example 4]
11.1 parts of propylene glycol monomethyl ether acetate (PMA) was added to 100 parts of the hydrophilic polyisocyanate composition a-2 obtained in Synthesis Example 2 of the polyisocyanate compound with stirring to obtain a transparent polyisocyanate. A mixture c-4 was obtained.
Table 1 shows the compositions of the polyisocyanate compositions obtained in Examples 1 to 8 and the polyisocyanate mixtures obtained in Comparative Examples 1 to 4.

[Reference Examples 1 to 4 and Reference Examples 5 to 7 (Comparative)]
Polyisocyanate compositions b-1, b-2, b-3, b-5 obtained in Examples 1, 2, 3, 5 and polyisocyanate mixtures c-1, c obtained in Comparative Examples 1-3 The aqueous polyol composition obtained in Formulation Example 1 of -2, c-3 and the aqueous polyol composition was mixed at an isocyanate group / hydroxyl group equivalent ratio = 1.0 to obtain an aqueous coating composition. This aqueous coating composition was applied to a glass plate so as to have a thickness of 40 μm (at the time of a dry coating film), cured for 7 days at 23 ° C. and 55% RH, and a water-resistant adhesion test was performed.
(Water adhesion test)
The sample was immersed in water for 24 hours and then visually observed.
Judgment was made based on the state of blisters formed between the glass substrate and the coating film.
The results are shown in Table 2.

[Reference Examples 8-11 and Reference Examples 12-14 (Comparative)]
Polyisocyanate compositions b-1, b-2, b-3, b-6 obtained in Examples 1, 3, 4, 6 and polyisocyanate mixtures c-1, c obtained in Comparative Examples 1-3 The aqueous polyol composition obtained in Formulation Example 1 of -2, c-3 and the aqueous polyol composition was mixed at an isocyanate group / hydroxyl group equivalent ratio = 1.0 to obtain an aqueous coating composition. This aqueous coating composition is applied to a substrate so as to be 40 μm (at the time of a dry coating film), cured for 7 days at 23 ° C. and 55% RH, and subjected to an aluminum adhesion test and a coating adhesion test under the following conditions. went.
(Aluminum adhesion test)
An aluminum plate (JIS H 4000 Allodin # 1000 treatment) was used as a substrate. The test was performed by a cross cut method of 100 squares, and the determination was made based on the number of squares that were not peeled off.
The results are shown in Table 3.
(Coating adhesion test)
A general-purpose solvent-based two-component polyurethane paint (white) was applied to an aluminum plate and sufficiently cured, and then treated with # 1000 sandpaper as a base material.
The adhesion test method and determination were performed in the same manner as the aluminum adhesion test.
The results are shown in Table 3.

[Reference Example 15]
The aqueous polyol composition obtained in Formulation Example 2 of the polyisocyanate composition b-8 obtained in Example 8 and the aqueous polyol composition was mixed at an isocyanate group / hydroxyl group equivalent ratio = 1.0 to obtain an aqueous coating composition. I got a thing.
This aqueous coating composition was applied to an alumite sulfate plate so as to have a dry film thickness of 100 g / m ² , cured for 4 weeks at 23 ° C. and 55% RH, and subjected to a rain stripe contamination test.
[Reference Example 16 (Comparison)]
The polyisocyanate mixture c-4 obtained in Comparative Example 4 and the aqueous polyol composition obtained in Formulation Example 2 of the aqueous polyol composition were mixed at an isocyanate group / hydroxyl group equivalent ratio = 1.0 to obtain an aqueous coating composition. Got.
This aqueous coating composition was applied to an alumite sulfate plate so as to have a dry film thickness of 100 g / m ^2, and cured for 4 weeks at 23 ° C. and 55% RH to perform rain stripe contamination.
(Rain-stain contamination test)
On the anodized sulfuric acid plate, the blends of Examples and Comparative Examples were applied with a wire coater so as to have a dry film thickness of 100 g / m ^2, and dried at room temperature for 4 weeks to obtain test specimens. The test specimen was fixed outdoors on the ground so that the coating surface was vertical and northward, and rain stain contamination was visually determined about 3 months after the start of exposure.

  The aqueous two-component polyurethane composition using the polyisocyanate composition of the present invention can be used as a raw material for paints, inks, adhesives, inks, casting materials, elastomers, foams, and plastic materials. Among them, it can be used for paints for buildings, paints for heavy anticorrosion, paints for automobiles, paints for home appliances, paints for information devices such as personal computers and mobile phones. It is particularly suitable for building exterior paints and heavy anticorrosion paints.

Claims (2)

(A) A polyisocyanate compound having a uretdione structure, a polyisocyanate compound having an isocyanurate structure or an iminooxadiazinedione structure, a biuret structure, which is derived from at least one diisocyanate selected from aliphatic diisocyanates and alicyclic diisocyanates. Polyisocyanate compound having oxadiazine trione structure, polyisocyanate compound having plural urethane groups, polyisocyanate compound having allophanate structure, polyisocyanate compound having acylurea group, polyisocyanate compound having urea structure At least one polyisocyanate compound selected from the group consisting of the polyisocyanate compound and alkoxy polyalkylene A polyisocyanate composition containing a polyisocyanate compound containing a reaction product with glycol and (B) a silane coupling agent having an isocyanate group, and used as a curing agent for an aqueous two-component polyurethane composition object. Further, (C) a tetraalkoxysilane represented by the following chemical formula (1), a tetraalkoxysilane condensate, a tetraalkoxysilane or a part of the alkoxy group of the tetraalkoxysilane condensate is a polyalkylene glycol monoalkyl ether, The polyisocyanate composition according to claim 1, comprising at least one alkoxysilane compound selected from the group consisting of tetraalkoxysilane compounds substituted with polyalkylene glycol monoaryl ethers.

(In the formula, R represents the same or different alkyl group having 1 to 10 carbon atoms or an aryl group.)