JPS6044561A - Rapidly-drying coating composition - Google Patents

Abstract

PURPOSE:The titled composition having improved rapidly drying properties and good workability, obtained by blending bisisocyanatoethyl isocyanato glutarate with a specific polyol resin. CONSTITUTION:(A) Bis(2-isocyanatoethyl)2-isocyanato glutarate is blended with (B) a polyol, preferably acrylic polyol resin having 20-300, preferably 20-200 hydroxyl number of resin, 500-30,000, preferably 1,000-25,000 number-average molecular weight, and >=two hydroxyl groups in one molecule in a molar ratio of isocyanate group in the component A to hydroxyl group in the component B of 1/5-2/1, preferably 1/2-3/2 to give the desired composition.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to quick-drying polyurethane coating compositions, more particularly bis(2-incyanatoethyl).
The present invention relates to a quick-drying non-yellowing polyurethane coating composition comprising a resin containing 2-incyanatoglutarate and at least two active hydrogen atoms.

Until now, organic polyisocyanates have been reacted with active hydrogen-containing compounds at room temperature or under heating to form polyurethanes/resins with excellent properties, especially mechanical strength, flexibility, chemical resistance, and gloss. It's fine,
Taking advantage of these excellent properties, polyurethane resins are widely used in paints, adhesive films, foams, elastomers, and sealants.

This polyurethane resin is classified into yellowing type and non-yellowing type depending on the type of polyinsyanate, and is used for applications that take advantage of the characteristics of each type.

Particularly in recent years, non-yellowing polyurethane resins using aliphatic and alicyclic polyisocyanates have shown remarkable growth mainly in the field of exterior applications due to their good weather resistance, light stability, and well-balanced physical properties. In particular, painting of vehicles such as automobiles, ships, aircraft, and railway vehicles, purchased buildings, woodwork, roof tiles, etc.
We have established a solid foothold in the field of exterior coatings for aluminum sashes, plastics, sporting goods, etc.

Conventionally, these non-yellowing polyiso7anates include hexamethylene diisocyanate), 2,2,4-trinotylhexamethylene diisocyanate-1, and inphoron diisocyanate.
Isocyanates, aliphatic or alicyclic diisocyanates such as synchhexylmethane diisocyanate, or derivatives thereof are generally used.

However, these non-yellowing aliphatic and alicyclic polyisocyanates generally have lower reactivity of their incyanate groups than aromatic polyisocyanates, so when reacting with a compound having active hydrogen, the curing rate is low. It has the disadvantage that the curing speed is particularly poor at room temperature or low temperature. This slow curing speed has a major impact on work such as nine layers of coating, color separation, and masking, especially in the painting field, especially in the automotive painting field, where these types of painting operations are common, and in the woodworking field, where quick drying is required. This has become a major problem as it causes a decrease in work efficiency.

Conventionally, in order to improve such normal C crystallinity or poor initial drying properties at low temperatures, for example, a part of aromatic or araliphatic polyisocyanate was blended with aliphatic or alicyclic polyisocyanate to achieve quick drying properties. A method is being used to grant this. However, paints made using this method have significantly lower weather resistance than paints made from aliphatic or alicyclic polyisocyanates, and the physical properties of the paint film, such as compatibility and oxidation resistance, are significantly impaired. It cannot be avoided from deteriorating.

In addition, attempts have been made to increase the apparent initial hardness by mixing alicyclic polyisocyanate with a glass transition temperature (Tg) above room temperature, such as inphorone diisocyanate polyisocyanate, with aliphatic polyinsyanate. In this method, the reactivity of alicyclic polyisocyanate is lower than that of aliphatic polyisocyanate, so although the apparent sensory dryness such as finger touch is increased, the true crosslinking reaction due to the reaction between isocyanate groups and hydroxyl groups is not possible. Wake up very late. As a result, the coating film produced by the above method has a serious drawback in that the development of important physical properties such as solvent resistance, impact resistance, flexibility, and adhesion is delayed. In addition, a method using curing catalyst sound is also proposed as a method to improve drying properties.

Addition of a curing catalyst causes a decrease in the gloss and adhesion of the paint film, and has the drawback of shortening the overall pot life of the paint. In this way, polyurethane resin decomposition, especially two-component polyurethane paints, In the field where good initial drying and curing properties are required, the current situation is that the physical properties of paints and coatings must be greatly influenced.

Therefore, in the polyurethane resin manufacturing industry, especially in the polyurethane resin paint manufacturing industry (( The appearance of polyisocyanates has been strongly desired.

In view of these circumstances, the inventors of the present invention have conducted extensive research to meet the demands of the polyurethane industry.
The present inventors have discovered that the object can be achieved by using a specific polyiso7anate as the iso/anate component and by appropriately selecting the polyol resin content, and have completed the present invention.

That is, the present invention comprises (a) bis(2--isocyanatoethyl) 2-incyanatogretarate and (b) a resin having a hydroxyl value of 20 to 300 and a number average molecular weight of 500 to 30.
A polyol resin having at least two hydroxyl groups in one molecule of 000 and an isocyanate group in the component (A)←
The present invention provides a quick-drying coating composition in which the molar ratio of hydroxyl groups in the components (1) to 21 is in the range of -5 to 21.

Bis(2-
Incyanatoethyl) 2-incyanatoglutarate is a triisocyanate having the chemical structure shown by the following formula.

ocN-aH2-aH2-oc-CH2-CH2-a
H-c-o-aH2-aH2-Ne.

CO This triisocyanate is obtained by, for example, esterifying glutamic acid or haglutamic acid hydrochloride with ethanolamine hydrochloride by any conventional method and reacting it with phosgene.It has a boiling point of 190°C, 10.1 Hg, and a viscosity at 25°C. It is a colorless and transparent liquid substance with a low viscosity of approximately 50 cps. Since this material has an extremely low vapor pressure at room temperature, it has no odor at all and is virtually non-irritating to the human body. Therefore, it has the advantage that it can be safely handled without being made into a prepolymer or diluting with a solvent. Furthermore, since the triyne/anate used in the present invention does not contain an aromatic group in its molecular skeleton, it is not stable against heat or light per se, and can be obtained as a raw material for the triisozoane). Weather resistance and light stability can be imparted to polyurethane resins. In order to achieve particularly excellent weather resistance, the raw material ethanolamine diester trihydrochloride of glutamic acid must be sufficiently refined to form the final product bis(2-isocyanatoethyl) 2-isocyanatoglutarate. It is desirable to use as component (a) a product with a hydrolyzed chlorine content of 0.3% or less.

Furthermore, the greatest feature of the composition provided by the present invention is its excellent drying properties, and this property is due to the presence of bis(2-incyanatoethyl) 2-isocyanatoglutarate used as component (a). This is based on the knowledge that all three inocyanate groups have an excellent property of being extremely fast in reactivity with hydroxyl groups, compared to ordinary aliphatic isocyanate groups. Therefore, in the composition of the present invention, the reaction rate between incyanate groups and hydroxyl groups is extremely fast compared to other compositions using egg yolk-distorted aliphatic isocyanates, so the apparent drying properties are
A major advantage is that the rate of excitation of the solvent resistance, impact resistance, bending resistance, adhesion, etc. of the coating film is very fast due to the formation of a network groove structure through the cross-linking reaction of the seven-dimensional cross-linking reaction.

Next, in the present invention, the polyol resin used as component (b) is a compound having a resin hydroxyl value of 20 to 300 and at least two hydroxyl groups in one molecule with a number average molecular weight of 500 to 30,000; Examples of such polyols include aliphatic hydrocarbon polyols, polyether polyols, polyester polyols, epoxy resins, and acrylic polyols. Specific examples of aliphatic hydrocarbon polyols include hydroxyl-terminated polybutadiene and hydrogen/additives thereof, and examples of polyether polyols include glycerin, propylene glycol, etc. Polyether polyols, polytetramethylene glycols, which are obtained by adding a single or a mixture of alkylene oxides such as ethylene oxide and propylene oxide to polyhydric alcohols alone or in mixtures; Polyether polyol-r reacted with a 9-functional compound
These include so-called polymer polyols obtained by polymerizing acrylamide and the like using these polyethers as a medium.

Examples of polyester polyols include dibasic acids selected from the group of carboxylic acids such as co-phosphoric acid, adipic acid, sepanonic acid, timer acid, dihydric maleic acid, phthalic anhydride, isophthalic acid, and hexaphthalic acid. and a polyhydric alcohol selected from sheep such as etching glycole, phlopylene gelicol, diethylene glycole, futhylene gelicol, neopentyl glycole, trimethylolpropane, glycerin, etc. Number average molecular weight obtained by condensation reaction: 500-300
00 polyester polyol resins and polycaprolactones such as those obtained by ring-opening polymerization of ε-caprolactone using a polyhydric alcohol.

In addition, examples of epoxy resins include novolak type,
β-methylepicro type, cyclic oxirane type, glycidyl ether type, glycidyl ether type, glycol ether type, epoxidized type of aliphatic unsaturated compound, epoxidized fatty acid ester type, polyvalent carboxylic acid ester type, aminoglycidyl type.

Examples include epoxy resins such as halogenated type and resolnon type.

Ushida acrylic polyols are obtained by copolymerizing a polymerizable monomer having one or more active hydrogens in one molecule and other monomers that can be copolymerized therewith. Examples of such substances include acrylic esters with active hydrogen such as 2-acrylate and droxyethyl, 2-hydroxypropyl acrylate, and 2-hydroxybutyl acrylate, 2-hydroxyethyl methacrylate, and methacrylate. Methacrylic acid esters with active hydrogen such as 2-hydroxypropyl acid and 2-hydroxybutyl methacrylate, acrylic acid monoesters or methacrylic acid monoesters of glycerin, acrylic acid monoesters or methacrylic acid monoesters of trinotyrolpropane Individually or in mixtures selected from the group of methyl acrylate, ethyl acrylate, isopropyl acrylate, n-butyl acrylate, acrylic acid 2-
Acrylic acid esters such as ethylhexyl.

A single or mixed methacrylate ester selected from the group of methacrylic acid esters such as methyl methacrylate, ethyl methacrylate, inopropyl methacrylate, -butyl methacrylate, isobutyl methacrylate, n-hexyl methacrylate, and lauryl methacrylate. The proboscis is unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, itaconic acid, unsaturated amides such as acrylamide, N-methylolacrylamide, diacetone acrylamide, and methacrylic (ef+) cidyl, styrene, vinyltoluene, vinyl acetate. , a number average molecular weight of 500 obtained by polymerization in the presence or absence of a single or a mixture of other polymerizable monomers such as acrylonitrile.
~30,000 acrylic polyol resins.

Among the polyols that can be used as the component (@) of the present invention, particularly preferred are those having a resin hydroxyl value of 20 to 200.
and acrylic polyols having a number average molecular weight of 500 to 30,000. If the hydroxyl value is less than 20, the density of crosslinking due to the reaction with triisonoanate will decrease, and the properties required for polyurethane resin, especially solvent resistance, will be extremely poor. On the contrary, the crosslinking density increases, and the mechanical properties of the polyurethane resin, especially impact resistance and elongation, become significantly low, which is not preferable. In addition, if the number average molecular weight is less than 500, it will not be possible to obtain a polyurethane resin with a good balance between hardness and elasticity.On the other hand, if the number average molecular weight is 30,000 or more, the viscosity of the polyol resin will increase and a large amount of solvent will be required. If it is not used, it will not be compatible with triisonoanate, making it impossible to obtain a homogeneous polyurethane resin, and will significantly reduce workability, which is not desirable. In order to obtain a polyurethane resin with excellent appearance and gloss and well-balanced physical properties, the resin should have a hydroxyl value of 20 to 200 and a number average molecular weight of 100 to 25.00.
Particularly preferred is the use of acrylic polyol resins having 0.

In the composition of the present invention, the molar ratio of isocyanate groups in component (a) to hydroxyl groups in component (b) is 15 to 2.
1, preferably l2 to l32.

If the molar ratio is 15 or more and there is an excess of hydroxyl groups, the solvent properties will be extremely poor, and if the molar ratio exceeds 2'1 and the isocyanate groups are in excess, the mechanical strength will deteriorate, which is undesirable.

In the composition of the present invention), when mixing both components, a suitable solvent such as benzene, toluene, xylene, cyclohexane, mineral spirit,
Depending on the purpose and use, use the appropriate one selected from the group of hydrocarbons such as naphtha, ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone, and esters such as left methyl acetate, n-butyl acetate, and cellosolve acetate. can do. These solvents may be used alone or in combination.

Furthermore, depending on the purpose and use, various additives commonly used in the technical field, such as catalysts, pigments, leveling agents, antioxidants, plasticizers, and surfactants, may be mixed and used.

The polyurethane resin formed from the composition of the present invention has weather resistance and yellowing resistance comparable to that of polyurethane resins using aliphatic polyino/anate, which has been highly evaluated conventionally, and at the same time has It has unparalleled drying and curing properties. therefore,
Coating materials, especially two-component polyurethane paints, for a wide range of coated objects such as metals, plastics, rubber, leather, concrete, and wood, automobiles, railway surfaces, aircraft, equipment, buildings, building materials, woodwork, and plastic products. It can be applied to a wide range of applications such as

EXAMPLES The present invention will be explained in more detail with reference to Examples below, but the present invention is not limited to these Examples in any way.

Reference Example 1 In a four-eye flask equipped with a stirrer, a temperature side, a waste inlet tube, and a Dean-Stark trap, glutamate hydrochloride 275F, ethanolamine hydrochloride soo fI, and toluene 150-m were placed, and hydrogen chloride gas was blown into the flask. The mixture was heated under reflux at 110° C. for 24 hours until water no longer azeotroped. The resulting viscous reaction mixture was mixed with methanol/
Recrystallized in ethanol mixed solvent, melting point 168-172
Bis(2-aminoethyl)glutamate trihydrochloride 2 °C
7Of I got everything.

The content of ethanolamine hydrochloride in this product is 5 M%
Met. (This is hereinafter referred to as raw material A.) This was heated at 60°C with a methanol/ethanol mixture and dried to obtain a tribasic acid salt having a melting point of 173 to 176°C. The content of ethanolamine hydrochloride in this product was reduced to 1.5%. The reaction was carried out at 135° C. for 13 hours while blowing at a high speed.

The reaction product was filtered and then concentrated under reduced pressure.
54 g of 2-incyanatogretarate was obtained. This product had an NCO content of 39.8% and a hydrolyzable chlorine content of 0.08%.

Reference Example 2 The reaction and purification were carried out in the same manner as in Reference Example 1 except that raw material A' (i) was used instead of raw material f-" and B, and the NCO content was 39
．． Section 4, bis(2-isonoanatoethyl) 2-isonoanatoglutarate having a hydrolyzable chlorine content of 0.4% was obtained.

Reference Example 3 The acrylic monomer composition shown in Table 1 was used as an initiator.
ert-butylperoxy-2-ethylhexanoe-1
1 and polymerized by a solution polymerization method to obtain an acrylic polyol. Solvent L-1; l:) toluene/
A butyl acetate (1/1) mixture was used. The physical properties of the obtained acrylic polyol are also shown in Table 1. (The following polyols in Table 1 (il-A, B, O, D, F
It is written as ) Reference Example 4 Using trimethylolpropane 1342 and ε-caprolactone 228t'ft tetrabutyl titanate as catalysts, ring-opening polymerization was carried out according to a conventional method to obtain 330 for number average molecules,
With OH (obtained from illi 510 polyester polyol):.

Examples 1 to 5, Comparative Examples 1 to 2 The polyincyanate shown in Reference Example 1 and the polyol resin solution were blended so that the isocyanate groups/hydroxyl groups were equal in amount, and acetic acid-r-f fluoride was added as a thinner to this. Add a mixed solvent of /toluene/butyl acetate/xylene/cellosolve acetate (overlapping ratio -30/30/20/1515),
The temperature was adjusted to 7725° C. for 20 seconds using a Ford cup 414 to obtain a coating composition of the present invention.

Use this with an air spray gun (IWATA W-61 type,
Paint with a nozzle diameter of 101m0 on iron plates, tinplate plates, and glass plates to a dry film thickness of 50μ, at 20℃/65%.
Changes over time under RH and physical properties after standing for 1'O days were measured.

In addition, for comparison with conventional products, two types of commercially available aliphatic polyisocyanates were added to the triiso/anate solution, namely: 1) frumodor N (manufactured by Bayer AG, hexamethylene diisosoanate burette) 2) Coronate H.L.
(manufactured by Nippon Polyurethane Industry ■, hexamethylene diisocyanate/trimethylolpropane adduct) was also subjected to all similar tests. The performance of the composition and the physical properties of the coating film are all shown in Table 2.

As is clear from Table 2, the composition of the present invention was the same as that of Comparative Example 1.
Comparison with the conventional product No. 2 (-) shows the same excellent general physical properties and surface 1 weatherability, and is significantly superior in coating film curing properties.

Comparative Example 3.4 Table 3 shows the results of blending, coating, and evaluation in the same manner as Examples 1 to 5 except for changing the polyol resin Table 3 Comparative Example 5 Acrylic acid 1 obtained under Reference Example 3 Using norpolyol, polyisocyanate of reference IZI 1 and NC010H = 1
．． When mixed at 0, the solution became cloudy due to poor compatibility between the two components, making it unsuitable for use as a paint.

Examples 6 and 7 Comparative Examples 6 and 7 Using the polyisocyanate of Reference Example 1 and the polyol resin of Reference Example 3-B, coating and evaluation were performed while changing the NC010H ratio. The results are shown in Table 1.

/''x'/' Example 8. Comparative Example 8 Using the same polyisocyanates as Reference Row 1 and Reference Example 2, a weather resistance test was conducted by QUV.

The results are shown in Table 5.

Table 5

Claims (1)

[Scope of Claims] 1 (a) bis(2-incyanatoethyl) 2-incyanatoglutarate; (0) resin hydroxyl value 20 to
300 and a number average molecular weight of 500 to 30,000 and a polyol resin having at least two hydroxyl groups in one molecule, the molar ratio of the in7anate groups in component (a) to the hydroxyl groups in component (b) is 1. A quick-drying coating composition which is blended so that it falls within the range of 5 to 2.1. 2. The composition according to claim 1, wherein the middle component is an acrylic polyol resin having a resin hydroxyl value of 20 to 200 and a number average molecular weight of 1,000 to 25,000. 3. The composition according to claim 1 or 2, wherein the molar ratio of isocyanate groups in component (a) to hydroxyl groups in component (b) is 12 to 32. 4. The composition according to claim 1 or 2, wherein component (a) is bis(2-incyanatoethyl)2-incyanatoglutarate containing 0.3% or less of hydrolyzable chlorine.