JP2000302745A - Polyisocyanate composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a polyisocyanate compound excellent in quick drying property and hypotoxicity and for obtaining the subject non-yellowing composition for a polyurethane resin excellent in high hardness, weather resistance and anti-yellowing property by reaction of lysine triisocyanate with water. SOLUTION: The polyisocyanate is obtained by reaction of lysine triisocyanate with water. The water for the reaction is 0.01-1.5 mol preferably 0.1-1 mol based on 1 mol lysine triisocyanate. As the above mentioned polyisocyanate, a compound of the formula (R1 to R9 are each a single bond, ethylene oxycarbonyl or tetramethylene) having a biuret linkage in the molecule is preferable. The objective polyisocyanate composition is obtained by including the polyisocyanate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to an aliphatic non-yellowing polyisocyanate suitable as a raw material for producing a polyurethane resin, especially a polyurethane resin coating, and more particularly to a novel polyisocyanate which is a reaction product of lysine triisocyanate and water. The present invention relates to a polyisocyanate composition containing an isocyanate compound or a reaction product thereof, and a non-yellowing type polyisocyanate composition containing these for a polyurethane resin paint.

[0002]

2. Description of the Related Art Polyurethane is a generic name of a polymer containing a urethane bond (-NHCOO-) in a molecule, and mainly includes a polyisocyanate having an isocyanate group (-N = C = O) in a molecule and a terminal of the molecule. And a polyol having two or more hydroxyl groups (-OH). Polyurethane resin is tough, excellent in wear resistance, oil resistance, solvent resistance, etc., and has rubber elasticity,
There are many uses such as paints, urethane foams, adhesives, elastic fibers, and synthetic leathers, and they have already been used in various fields. Polyurethane has a wide variety of resin raw materials, and it is well known that the characteristics of the resin vary significantly depending on the raw material used.

[0003] Further, polyurethane resins are roughly classified into a yellowing type, which yellows by light or heat, and a non-yellowing type, which hardly changes according to the type of polyisocyanate used. Classified as a variant. And, as main yellowing type polyisocyanate, toluene diisocyanate (TDI), 4,
Aromatic isocyanates such as 4'-diphenylmethane diisocyanate (MDI) and naphthalene diisocyanate (NDI) can be mentioned. The main non-yellowing isocyanates are hexamethylene diisocyanate (HDI) and isophorone diisocyanate (IPD).
I), aliphatic polyisocyanates such as hydrogenated xylene diisocyanate (HXDI) and lysine triisocyanate (LTI). Further, examples of the non-yellowing isocyanate include xylene diisocyanate (XDI).

[0004] Aromatic polyisocyanates have high activity and excellent drying properties, but are highly toxic.
It is known that monomers, MDI monomers, and the like have a high vapor pressure and are liable to cause health problems. In particular, in the case of TDI-based polyisocyanate, the TDI monomer reacts with moisture in the air during the drying process, and is a carcinogenic substance.
There is also a report that 4-toluenediamine (2,4TDI) is detected. In the lacquer industry, harmfulness to the human body is an important factor, for example, when painting on tableware, it must pass the standards of the Ministry of Health and Welfare Notification No. 20 based on the Food Sanitation Law. Thus, these polyisocyanate compounds are generally used as polyisocyanate derivatives such as adducts with polyols, regenerated polyisocyanates, and isocyanate multimers.

[0005] On the other hand, aliphatic polyisocyanates have low toxicity, but have the drawback of extremely poor drying properties. For example, IPDI-based polyisocyanates have relatively good initial drying properties, but are rarely used singly due to disadvantages such as poor internal curing, brittle brittleness, and easy damage.
It is often used as a modifier, for example, by mixing with a DI polyisocyanate.

As mentioned above, polyurethanes are mainly produced by the reaction of polyisocyanates and polyols. As such polyols, various polyols such as acrylic polyols, polyester polyols, polyether polyols, alkyd polyols, polybutadiene polyols, and fluorine-based polyols are known, and these polyols are also used in the same manner as the polyisocyanate, depending on the application. It is known that the type and the mixing ratio are selected and used.

Further, the properties of the polyurethane resin vary depending on the bonding mode and the crosslinking density contained therein. For example, polyols (curing agents) having a short chain length between functional groups or polyfunctional polyisocyanates When used, the crosslink density of the formed resin increases and the product becomes hard.When a tertiary amine is used as a curing accelerator, the resin becomes hard with many urea bonds and biuret bonds, but generally the weather resistance is deteriorated. It is also known that when cured with a polyol, it becomes relatively soft because it contains a large number of urethane bonds and the initial drying property is poor. In addition, the polymerization of the polyol component, the combined use of nitrified cotton, etc. improve the initial drying property, but make the meat feel poor, and the combined use of an antiblocking agent such as organic silicon lacks recoating properties such as lacquer work. It is also known that there is.

[0008] In addition, there is known a coating composition mainly comprising a polyurethane resin obtained by reacting lysine triisocyanate as a polyisocyanate with a polyol (Japanese Patent Publication No. 57-20343).
However, the polyurethane resin coating film by this coating composition,
It is not yet sufficient in terms of quick drying, curing degree, weather resistance, coating appearance, and the like.

[0009]

[Problems to be Solved by the Invention] Polyurethane resin paints, which dominate the paint industry such as woodwork, lacquer work, and building materials, have excellent initial drying properties, and excellent physical properties such as high hardness, weather resistance, and yellowing resistance. At the same time, something that has a sense of solidity is always required, and R & D is still ongoing. In order to respond to such user needs, there are many choices such as selection of polyol components, polymerization, combined use of nitrified cotton, addition of drying accelerator, addition of anti-blocking agents such as organic silicon and waxes as abrasion resistance improver. Investigations have been made, and they are often regarded as know-how in the preparation of paints. However, no satisfactory polyurethane resin paints having excellent physical properties described above have been reported yet.

[0010] In particular, with respect to drying properties, the final hardness after aging reaches a practical range regardless of the use of an aromatic polyisocyanate or an aliphatic polyisocyanate. The dried state of the coating film after 1-2 days has a very important industrial significance. Even in the case of heating and drying by a painting line in the fields of automobiles, home appliances, architecture, toys, etc., for example, 70 ° C., 40
In practice, the initial drying property is considered to be extremely important, for example, the quality of the coating is evaluated in the state of the coating film after minutes. In meeting the need for such dryness,
Continuous research is being carried out from both sides of polyols and polyisocyanates.

An object of the present invention is to provide a quick drying, less toxic, high hardness, weather resistance and yellowing resistance as compared with various derivatives such as hexamethylene diisocyanate and isophorone diisocyanate which are generally used as non-yellowing isocyanates. An object of the present invention is to provide a non-yellowing type polyisocyanate composition for a polyurethane resin which is excellent in various physical properties such as modification.

[0012]

The present inventors have conducted intensive studies to solve the problems of the prior art, and as a result, by using a lysine triisocyanate derivative and a polyol, the dryness, hardness, weather resistance and the like have been improved. It has been found that a polyurethane resin paint having excellent physical properties can be produced, and the present invention has been completed.

That is, the present invention provides a polyisocyanate compound produced by the reaction of lysine triisocyanate with water (claim 1) and a polyisocyanate compound represented by the general formula (I) having a biuret bond in the molecule. Isocyanate compound

Embedded image (Wherein, R _{1 to} R ₃ each independently represent a single bond, an ethyleneoxycarbonyl group or a tetramethylene group;
_{4 to} R ₆ and R _{7 to} R ₉ , like R _{1 to} R ₃ , are each different and represent a single bond, an ethyleneoxycarbonyl group or a tetramethylene group. ) (Claim 2) or Claim 1 or 2
A composition for a polyurethane resin coating, comprising the polyisocyanate compound according to claim 3,
The present invention relates to a polyisocyanate composition containing a polyisocyanate compound generated by a reaction between lysine triisocyanate and water (claim 4).

The polyisocyanate composition according to claim 4, which further comprises a polyisocyanate compound represented by the general formula (I) having a biuret bond in the molecule.

Embedded image (Wherein, R _{1 to} R ₃ each independently represent a single bond, an ethyleneoxycarbonyl group or a tetramethylene group;
_{4 to} R ₆ and R _{7 to} R ₉ are also different from each other, and a single bond,
Represents an ethyleneoxycarbonyl group or a tetramethylene group. ) (Claim 5) or a composition for a polyurethane resin coating containing the polyisocyanate composition according to the claim 4 or 5 (Claim 6), or a polyurethane resin coating according to the claim 3 or 6 The present invention relates to a polyurethane resin paint (claim 7), which is prepared from a composition for use and a polyol.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Lysine triisocyanate, which is a raw material of the polyisocyanate compound and the polyisocyanate composition of the present invention, is a derivative derived from lysine, which is a protein component, and is represented by the following formula (II). It is a compound having three isocyanate groups in one molecule.

Embedded image

Since lysine triisocyanate is an aliphatic polyisocyanate having no benzene nucleus, the polyisocyanate compound or polyisocyanate composition of the present invention is produced using the lysine triisocyanate as a raw material, and a polyurethane resin paint is prepared by using these. In production, carcinogenic substances such as 2,4-toluenediamine are not generated during the drying process. Conventional polyisocyanate adducts using hexamethylene diisocyanate as a raw material are said to release highly toxic monomers during storage and storage or during painting, whereas the boiling point of lysine triisocyanate monomer is 135 ° C. /0.1 mmHg, which is very high, and hardly evaporates into the environment.

The polyisocyanate compound of the present invention is produced by a reaction between lysine triisocyanate and water.
And the polyisocyanate compound which is the reaction product of such lysine triisocyanate and water is usually produced as a mixture of various polyisocyanate compounds, that is, as a polyisocyanate compound, but what kind of polyisocyanate compound is produced This depends on the mixing ratio of lysine triisocyanate and water and the reaction conditions.

The amount of water to be reacted with lysine triisocyanate is based on 1 mole of lysine triisocyanate.
The amount is 0.01 to 1.5 mol, preferably 0.1 to 1 mol, particularly preferably 0.2 to 0.5 mol. If the amount of the water to be reacted is too large, the polymerization proceeds, and the compatibility with the polyols becomes poor. If the amount is too small, the amount of the reaction product obtained decreases, and the reaction efficiency decreases. And
When used in an appropriate range, good compatibility with various polyols, excellent drying properties and hardness, and improved weather resistance can be obtained, and good results can be obtained in the properties of a coating film when a paint is formed.

The reaction between lysine triisocyanate and water starts when the isocyanate group in lysine triisocyanate reacts with water as shown by the following reaction formula, and first, an amine compound is formed.

Embedded image

The amino group of this amine compound further reacts with the isocyanate group in lysine triisocyanate as shown by the following reaction formula, and as a result, a compound having the following urea bond is formed. Since the compound having a urea bond has a tetrafunctional isocyanate group, it is included in the polyisocyanate compounds of the present invention.

Embedded image

The urea bond in the compound having a urea bond further reacts with an isocyanate group in lysine triisocyanate as shown by the following reaction formula.
The following compound having a biuret bond is produced. Since the compound having a biuret bond has six isocyanate groups, it is included in the polyisocyanate compounds of the present invention.

Embedded image

Among the polyisocyanate compounds of the present invention having a biuret bond and six isocyanate groups, 3 mol of lysine triisocyanate monomer and 1 mol of water
Examples of the polyisocyanate compounds generated by the reaction of mol include the compounds represented by the general formula (I).

In the compound represented by the general formula (I), one isocyanate group in one molecule of lysine triisocyanate reacts with water to become an amino group, and the amino group is added to the isocyanate group in two molecules of lysine triisocyanate. Is a compound having a biuret bond reacted one by one, and 0.5 mol of water is added to 3 mol of lysine triisocyanate.
By reacting 〜1.2 mol, a compound having a biuret bond represented by this general formula (I) can be produced with high selectivity.

The main reaction product of lysine triisocyanate and water has been described above. Lysine triisocyanate has three isocyanate groups. How many isocyanate groups are converted to amino groups and how much of the total lysine triisocyanate is converted to compounds with amino groups,
The polyisocyanate compounds of the present invention having various urea bonds and biuret bonds are produced depending on the amount of water to be reacted and reaction conditions such as which isocyanate group in the lysine triisocyanate molecule reacts with the generated amino group.

The polyisocyanate composition of the present invention is a composition containing the above-mentioned polyisocyanate compounds produced by the reaction of lysine triisocyanate with water. Lysine triisocyanate used as a raw material may be present in addition to the reaction product of water and water. The amount of the lysine triisocyanate as a raw material is preferably less than 50% by weight in consideration of the effect on the film properties when a polyurethane resin coating is used.

The polyurethane resin coating composition of the present invention contains the polyisocyanate compound of the present invention, such as the compound represented by the general formula (I), and the polyisocyanate composition of the present invention. The polyurethane resin paint composition of the present invention can be used in combination with a polyol to prepare a polyurethane resin paint.
Such polyol may be any polyol containing a compound or polymer containing two or more hydroxyl groups per molecule, such as diol, triol, tetraol, pentol, hexitol and these. And polyether polyols, polyester polyols, and polymer polyols containing two or more hydroxyl groups per molecule, and these can be used in combination. Specific examples include the following compounds.

Specific examples of the diol include ethylene glycol, propylene glycol, β, β-dihydroxydiethyl ether (diethylene glycol), dipropylene glycol, 1,4-butylene glycol,
Examples thereof include 3-butylene glycol, polyethylene glycol, polypropylene glycol, polypropylene-polyethylene glycol, and polybutylene glycol.

Specific examples of the polyol include glycerin, trimethylolpropane, pentaerythritol,
Sorbitol, 2-methylglucoside, 1,2,6-
Compounds having two or more hydroxyl groups in one molecule such as hexanetriol can be exemplified.

Specific examples of polyether polyols include preparations obtained by adding propylene oxide, ethylene oxide and the like to a polyhydric alcohol such as glycerin and propylene glycol. Further, a polyether polyol rich in hydroxyl groups obtained by reacting a polyfunctional compound such as ethylenediamine or ethanolamine with ethylene oxide or propylene oxide can also be used.

Specific examples of the polyester polyol include carboxylic acids such as adipic acid, dimer acid, phthalic anhydride and isophthalic acid, and diols such as ethylene glycol, diethylene glycol, propylene glycol, trimethylolpropane and glycerin, and triols. A polyester polyol synthesized by a condensation reaction can be exemplified.

Specific examples of the polymer polyol include:
A polymer polyol which can be prepared by copolymerizing a polymerizable monomer having one or more hydroxyl groups in one molecule and another monomer copolymerizable therewith can be exemplified. Examples of the polymerizable monomer having one or more hydroxyl groups in one molecule include 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxybutyl acrylate, 2-hydroxyethyl methacrylate, and methacrylic acid. 2-hydroxypropyl acid, 3-hydroxypropyl methacrylate, 4-hydroxybutyl methacrylate, 2-hydroxypentyl methacrylate, methacrylic acid monoester, trimethylolpropane acrylic acid monoester, methacrylic acid monoester Examples thereof include esters, 2-hydroxy-3-chloropropyl acrylate, and 2-hydroxy-3-chloropropyl methacrylate.

Next, other monomers copolymerizable with the above-mentioned hydroxyl group-containing acrylate or methacrylate include acrylic acid or acrylates such as methyl, ethyl, propyl, butyl and 2-ethylhexyl. , Methacrylic acid or methyl methacrylate, ethyl, butyl, decyl, 2-ethylhexyl, methacrylic acid esters such as lauryl, or α-methylstyrene, styrene derivatives such as β-chlorostyrene,
Examples thereof include vinyl esters such as vinyl acetate, vinyl propionate and vinyl isopropionate, and nitriles such as acrylonitrile and methacrylonitrile. In addition, a polymerizable adduct formed by an addition reaction of acrylic acid or methacrylic acid with an epoxy compound such as Cardiura E (product of Ciel Chemical) or an epoxy resin such as Epicoat 1001 (product of Ciel Chemical) is also used. .

Among the above-mentioned various monomers, most preferred among the hydroxyalkyl (meth) acrylates are 2-hydroxyethyl methacrylate, 2-hydroxyethyl acrylate, and 2-hydroxypropyl methacrylate; Examples of other monomers include methyl acrylate, ethyl acrylate, butyl acrylate, methyl methacrylate, butyl methacrylate, lauryl methacrylate, acrylic acid, methacrylic acid, styrene, acrylamide, and vinyl acetate.

Although the various polyols have been specifically exemplified above, the polyol of the present invention is not limited thereto, and can form a urethane bond by reacting with the polyisocyanate compound or the polyisocyanate composition of the present invention. Any polyol can be used as long as it is a polyol, and various combinations of polyols can be selected.

The polyurethane resin is synthesized from the above-mentioned various polyols and the polyisocyanate compound or polyisocyanate composition of the present invention, and includes various polyurethanes including films, coatings, elastomers, foams, curing agents, adhesives and the like. It can be a product, but a polyurethane resin paint is particularly suitable.

NCO / O in polyol type and composition
By adjusting the H ratio, etc., various properties and properties of the polyurethane resin such as the strength, flexibility, chemical resistance, and solvent resistance of the coating can be changed over a wide range. it can. For example, NC in the composition of the present invention
Compositions having an O / OH ratio (molar ratio) in the range of 0.5 to 2.0 are suitable for producing films and coatings. 0.5 to 1.2 NCO / OH for polyurethane coatings
Is preferred. Those having an NCO / OH ratio of 0.5 to 1.0 are useful in the field of electric insulation or in the field of encapsulation, and in cast products. Further, the NCO / OH ratio is 0.1 to 0.1.
The case of 7 is preferable for the production of a high-grade adhesive or curing agent, while the case of a large NCO / OH ratio is suitable for the production of a foam. Foaming can be effected by introducing a certain amount of water or a blowing agent into the reaction product by known foaming techniques.

The polyurethane resin paint obtained according to the present invention can be applied to a wide range of uses in a usual use form as a two-pack type or a one-pack type. For example, in the case of a two-pack type polyol curing type, a coating film is formed by urethane bonds generated by an addition reaction between an isocyanate group and a hydroxyl group of the polyol. As the polyol component, a polyester polyol composed of a polybasic acid and a hydroxyl compound, a polyether polyol composed of a diol or triol type propylene oxide polymer, an acrylic polyol composed of a copolymer of an acrylic monomer having a hydroxyl group, and the like are preferable. Depending on the type and combination of the polyisocyanate compounds and polyols, a flexible to hard and tough coating film or a coating film having excellent weather resistance, water resistance, chemical resistance and stain resistance can be obtained. Such two-component curing types include metal, non-ferrous metal, plastic, rubber,
It has excellent adhesion to objects to be coated such as leather and concrete, and has a wide range of applications such as building materials, automobiles, machines, equipment, aircraft, railway vehicles, ships, and wood products.

In the two-part curing type, since the reaction proceeds even at room temperature, the pot life of the paint, that is, the pot life becomes a problem. In such a case, a one-component heat curing type is usually used. In the case of this one-component heat curing type, for example, the isocyanate group of a polyisocyanate compound is blocked with a blocking agent, and the blocking agent is dissociated by heating to regenerate the isocyanate group. It is formed. This method is suitable for applications requiring storage stability at room temperature, such as automotive line coating. And
As the polyol to be combined with the block-type polyisocyanate prepolymer, a polyester polyol and an acrylic polyol are mainly preferred.

Examples of the blocking agent for masking free isocyanate groups of the polyisocyanate compound of the present invention include phenol, m-nitrophenol, p-chlorophenol, catechol, ethyl malonate, acetylacetone, ethyl acetoacetate, cresol, ε
-Caprolactam, methyl ethyl ketoxime, cyclohexanone oxime, butyl mercaptan, methanol,
Commonly used blocking agents such as ethanol and ethylene chlorohydrin can be used. The dissociation temperature of such a blocking agent varies depending on its type, but generally requires at least 120 ° C. Due to the need for baking at a relatively high temperature, this type is mainly used in the fields of electric wires, but new developments such as application to powder coatings and aqueous emulsion coatings based on polyurethane resin are expected. Is done.

A solvent is usually used for the polyurethane resin paint. As such a solvent, a solvent having no active hydrogen atom is preferable. Therefore, a solvent that does not react with the isocyanate group is also preferable as a solvent for dissolving the polyol, and hydrocarbon solvents such as benzene, toluene, xylene, and aromatic naphtha, ethyl acetate, butyl acetate, cellosolve, hexyl acetate, amyl acetate, and propionic acid ethyl,
Ester solvents such as butyl propionate; ketone solvents such as acetone, methyl ethyl ketone, methyl isopropyl ketone, methyl isobutyl ketone, diethyl ketone and cyclohexanone; and glycol ester solvents such as ethylene glycol monoethyl ether acetate and diethylene glycol monoethyl ether acetate. preferable.

The reaction temperature for producing a polyurethane product is preferably in the range of 20 to 160 ° C. A desirable reaction is a reaction between an isocyanate group and a hydroxyl group that forms a urethane bond, but a reaction between an isocyanate group and an active hydrogen atom other than the hydroxyl group can also be performed. Such active hydrogen donors include
Examples include amines, acids, substituted ureas, urethanes, amides, and the like. Specifically, the isocyanate group further reacts with the -NH group of the urethane bond formed by the reaction with the hydroxyl group at a relatively high temperature to form an allophanate bond. Similarly, a biuret bond is formed from a urea bond and an isocyanate group, and an acylurea bond is formed from an amide bond and an isocyanate group. In this way, a wide variety of reactions are possible, which can be utilized depending on the intended use. If necessary, auxiliaries commonly used in the art such as antioxidants, pigments, plasticizers, catalysts, surfactants and the like can be added to the reactants.

When the polyisocyanate composition of the present invention is coated with various polyols such as acrylic polyols and polyester polyols to form a coating, it is rapidly dried to have high hardness, excellent weather resistance and compatibility with most polyols. Is presumed to be due to its composition and chemical structure. That is, while a conventional polyisocyanate such as lysine triisocyanate or HDI is a trifunctional compound, for example, a compound represented by the general formula (I) (hereinafter referred to as “LTI biuret”) is a hexafunctional compound. This is probably because a coating film having a high crosslinking density was obtained.

It is well known that a dried coating film has high hardness in practice and, if it does not have a certain degree of flexibility, causes chalking to promote deterioration of the coating film. Needless to say, the flexibility of the polyurethane resin depends on the properties of the polyol and the polyisocyanate, but the latter is often affected by the latter. In general, the flexibility of a polyisocyanate is larger in the biuret form than in the adduct form, which is derived from the number of methylene bonds in the structure. Therefore, the lysine triisocyanate (hereinafter referred to as “LTI”) monomer has a lower LT
It is presumed that I-biuret has better weather resistance due to its chemical structure.

[0044]

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. Example 1 Synthesis of LTI Biuret In a four-necked flask equipped with a thermometer, a reflux condenser, a nitrogen gas inlet tube, and a stirrer, 801 g (3 mol) of LTI monomer and 80 g of cellosolve acetate were charged, and water was added to 14.4 g of water.
g (0.8 mol), acetone 14.4 g, MEK90
g and 90 g of cellosolve acetate are gradually added at 65 to 70 ° C. over 1 hour while stirring with a dropping funnel. The temperature is further maintained at 65 to 70 ° C. for 5 hours to complete the reaction. The product has a heating residue of 74.8% and an NCO of 28.
9% (theoretical 26.4%). 1 and 2 show the results of IR analysis before and after the reaction, respectively. FIG.
From the comparison between FIG. 2 and FIG. 2, after the reaction, 3,300, 1,65
Absorption of NH and the like newly appears at ⁰ and 1,560 cm ^-1 . In addition, the ¹³ C-NMR (DMSO) analysis result 120
~130ppm (-N C O), 170~175ppm
(- C OO -), 150~160ppm (-N C ONH
−).

2. Preparation of paints As shown in Table 1, in addition to the LTI biuret of the present invention, conventional isocyanates were used as comparative examples as isocyanates. The polyols described in Table 2 were used. Also, polyisocyanates and polyols are NCO: OH =
The mixture was mixed at a ratio of 1: 1 to prepare a polyurethane resin paint by a conventional method.

[0046]

[Table 1]

[0047]

[Table 2]

3. Various test methods (1) Compatibility The LTI biuret of the present invention and various polyols are mixed, and this mixture is applied to a glass plate with a 250 μ applicator. .

(2) Coating film hardness (drying property) After being diluted with a thinner to 16-18 seconds of Iwata cup, 1
After applying to a glass plate with a 50μ applicator,
-15 ° C), and the change over time in pencil hardness is measured with a pencil scratch tester (manufactured by Honji Co., Ltd.). The pencil hardness is (soft) 1 of 6B-B, HB, F, H-9H (hard).
Seven types were adopted.

(3) Yellowing test A 150 × 70 × 0.8 mm mild steel plate was polished with # 180 abrasive paper, and then coated with a non-yellowing type polyurethane resin paint white (manufactured by Saito Co., Ltd.). After spray coating the paint (clear) to a coating thickness of 35-40 μm,
After drying at ℃ for 14 days, the color difference (△ E) was measured at regular intervals using a color difference meter (manufactured by Nippon Denshoku Co., Ltd.) using a sunshine carbon arc lamp type weather resistance tester (manufactured by Suga Test Instruments Co., Ltd.).
Was measured and evaluated. ΔE indicates that the larger the value, the greater the discoloration.

(4) Weathering Acceleration Test A test piece was prepared on a 150 × 70 × 13 mm U.S. pine muk wood by the following coating process, and coated with a sunshine carbon arc lamp type weathering tester (manufactured by Suga Test Instruments Co., Ltd.). The change with time of the film gloss was measured. The gloss remaining ratio as the coating film gloss was measured using a 60-degree specular gloss meter (manufactured by Murakami Color Materials Co., Ltd.)
The state of the coating film (appearance) was visually determined. Two test pieces were prepared for each test piece, and the average value was used as the test result. (Coating process) Base adjustment: Polishing with sandpaper # 180 Undercoating: # 1010 wood sealer (manufactured by Saito Co.) Middle coating: ¥ 3,000 clear (manufactured by Saito Co.) Polishing: Polishing with # 400 Coating: Coating test material # 3000 clear, 5 minutes (Saito Co., Ltd.)

4. Test Results (Compatibility) The compatibility between the LTI biuret of the present invention and various commercially available polyols shown below was good. Acrylic polyol Acridic A-801 (manufactured by Dainippon Ink and Chemicals, Inc.) Acrydic BU-955 (manufactured by Dainippon Ink and Chemicals, Inc.) Hitaloid D-1004 (manufactured by Hitachi Chemical Co., Ltd.) Polyester polyol Takerac U-25 (Manufactured by Takeda Pharmaceutical Co., Ltd.) Desmochen D-1300-75 (manufactured by Sumitomo Bayer Co., Ltd.) Alkyd polyol ST-190 (manufactured by Toshin Yushi Co., Ltd.) Haripol F-16 (manufactured by Harima Chemicals Co., Ltd.) Fluoropolyol Lumiflon LF300 (made by Asahi Glass Co., Ltd.)

(Coating film hardness) Table 3 shows the test results of coating film hardness (drying property). From Table 3, when the LTI biuret of the present invention was used as the polyisocyanate, the LTI monomer, HDI biuret (24A-90PX), IPD
It turns out that the drying property of the polyurethane resin paint, especially the initial drying property, is superior to the case where I adduct (D-140N) is used.

[0054]

[Table 3]

(Yellowing Test) Table 4 shows the results of a yellowing test in the case where Hitaloid D-1004 was used as a polyol and this was combined with various polyisocyanates. Table 4 shows that LT of the present invention was used as a polyisocyanate.
When I biuret is used, the yellowing of the polyurethane resin paint is as high as that when the LTI monomer is used.
Color difference (ΔE) compared to the case using I biuret (24A-90PX) or IPDI adduct (D-140N)
Is small and excellent. When D-750, which is an aromatic polyisocyanate, is used, the color difference (ΔE) is large, and it can be seen that yellowing appears strongly.

[0056]

[Table 4]

(Weather Resistance Acceleration Test) First, the surface of a polyurethane resin paint prepared by using an LTI monomer and HDI biuret (Duranate 24A-90PX) as a polyisocyanate and using 3,000 clear (manufactured by Saito Co., Ltd.) as a polyol was used. After 5 minutes, the gloss remaining ratio (%) and the change in appearance of both were measured over time.
The results are shown in Table 5 and FIG. From Table 5 and FIG.
It can be seen that the coating film using HDI biuret is more excellent in gloss retention (%) and appearance than using the monomer.

[0058]

[Table 5]

Similarly, the LTI biuret of the present invention and HDI biuret (Duranate 24A-90PX) were used as the polyisocyanate, and the polyol was # 30.
The gloss retention (%) and the change in appearance of the coated surface of the polyurethane resin paint prepared using 00 Clear (manufactured by Saito Co., Ltd.) were also measured over time. The results are shown in Table 6 and FIG. From Table 6 and FIG. 4, it can be seen that when the LTI biuret was used, excellent gloss retention (%) and the state of the coating film (appearance) were exhibited in the same manner as when the HDI biuret was used.

[0060]

[Table 6]

[0061]

As described above, the polyisocyanate composition of the present invention comprises:
Polyurethane resin coatings which are excellent in compatibility with various polyols and prepared using the polyisocyanate composition of the present invention are faster drying and more durable than conventional polyurethane resin coatings using a non-yellowing type polyisocyanate. It is excellent in film hardness and has properties comparable to HDI biuret and the like, which are currently considered to be the best in weather resistance and yellowing resistance, so that it can satisfy user needs in woodworking, lacquer work, building materials related industries and the like.

LTI biuret, which is a main component of the polyisocyanate composition of the present invention, is a derivative of LTI derived from lysine, which is a protein component, belongs to aliphatic non-yellowing isocyanates, and has a benzene nucleus. Therefore, carcinogenic substances such as 2.4 toluenediamine are not generated in the drying process. In addition, HDI
It is said that the conventional polyisocyanate adducts and the like which are used as starting materials release highly toxic monomers during storage and storage or during painting, whereas the LTI monomer has a boiling point of 135 ° C./0.1 mmHg. And it is extremely safe in handling work.

[Brief description of the drawings]

FIG. 1 is a view showing an IR analysis result of an LTI monomer.

FIG. 2 is a view showing an IR analysis result of LTI biuret.

FIG. 3 shows LTI monomer and HD in accelerated weathering test
It is a figure showing the comparison result at the time of using I biuret.

FIG. 4 is a diagram showing a comparison result in the case of using an LTI biuret and an HDI biuret of the present invention in a weather resistance acceleration test.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kenji Komiyama 420-1 Nedo, Kashiwa-shi, Chiba corp. Nobuhara Kowa 272-1 Goi, Ichihara-shi, Chiba Pref. DF22 DG03 DG04 DG05 DG08 DG09 DP03 DP13 DP18 HA01 HA08 HA09 HA11 HB08 HC03 HC08 JA02 QA03 RA07 RA08 RA14 4J038 DG031 DG261 DG262 DG271 DG272 DG291 DG292

Claims (7)

[Claims] 1. A polyisocyanate compound formed by reacting lysine triisocyanate with water. 2. The polyisocyanate compound according to claim 1, which is represented by the general formula (I) having a biuret bond in the molecule. Embedded image (Wherein, R _{1 to} R ₃ each independently represent a single bond, an ethyleneoxycarbonyl group or a tetramethylene group;
_{4 to} R ₆ and R _{7 to} R ₉ , like R _{1 to} R ₃ , are each different and represent a single bond, an ethyleneoxycarbonyl group or a tetramethylene group. ) 3. A composition for a polyurethane resin coating, comprising the polyisocyanate compound according to claim 1 or 2. 4. A polyisocyanate composition containing a polyisocyanate compound formed by reacting lysine triisocyanate with water. 5. The polyisocyanate composition according to claim 4, comprising a polyisocyanate compound having a biuret bond in the molecule and represented by the general formula (I). Embedded image (Wherein, R _{1 to} R ₃ each independently represent a single bond, an ethyleneoxycarbonyl group or a tetramethylene group;
_{4 to} R ₆ and R _{7 to} R ₉ are also different from each other, and a single bond,
Represents an ethyleneoxycarbonyl group or a tetramethylene group. ) 6. A composition for a polyurethane resin coating, comprising the polyisocyanate composition according to claim 4. Description: 7. A polyurethane resin paint prepared from the polyurethane resin paint composition according to claim 3 or 6 and a polyol.