JP2003012750A - Curable composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain both a curable composition in which solubility of a catalyst is raised and the catalyst can be activated at a low temperature and which is cured at a medium temperature in a short time by combining a specific curing agent with a catalyst and a curable composition in which foaming can be controlled by a bifunctional epoxide contained. SOLUTION: In a curing system of a polyisocyanate, the polyisocyanate is cured at a medium temperature in a short time by using the combination of the specific curing agent and the catalyst.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a curable polyurethane composition which is excellent in curability, appearance of a coating film after curing, mechanical strength and heat resistance, and an organic polyisocyanate, a hydroxyl group-containing compound, an epoxy-containing compound, and Seed curable resin composition. It also relates to the use of this composition for the production of all types of composite articles and for the production of the most diverse types of coatings and adhesives. The curable composition according to the invention is furthermore also suitable for adhesives which can be used at low temperature energy.

[0002]

Polymers having an isocyanate group are
It is widely used for sealing materials, paints, adhesives, etc. because it easily becomes high molecular weight by reacting with a compound containing active hydrogen or water. These isocyanate group-containing polymers are mixed with polyamines, amino alcohols, glycols, polyols and the like and used as a one-component or two-component curable composition. However, the one-pack curable composition made of a polymer having an isocyanate group has a problem that expansion and foaming occur due to carbon dioxide gas generated during curing. There is also a problem that when the cured product is heated, it softens.

Reaction mixtures of polyepoxys, polyisocyanates, and certain catalysts are known. In this regard, the catalysts used are especially tertiary amines, but mixtures of these tertiary amines as catalysts are either too fast or too slow to give suitable cure rates. Has not been done. If the cure is too fast, it is difficult to avoid shrinkage, crack formation, and bubble formation in the resulting cured reaction resin. On the other hand, the slow curing reaction is not economically preferable. Further, even if a metal halide catalyst was used, a very high temperature of 160 ° C. or higher was required for the curing reaction.

On the other hand, Japanese Patent Application Laid-Open No. 7-304840 proposes that a specific tertiary amine is used as a catalyst to cure in an economically reasonable time without excessive release of heat. However, in this case as well, 130 ° C, 4
The condition of time is necessary.

[0005]

The object of the present invention is to increase the solubility of the catalyst and activate it at a low temperature by combining a specific curing agent (hereinafter also referred to as a cross-linking agent) and the catalyst. A curable composition which can be cured at an intermediate temperature for a short time, and a curable composition in which foaming can be controlled by the contained bifunctional epoxide.

[0006]

The present inventor has found that in a polyisocyanate curing system, if a specific combination of a curing agent (crosslinking agent) and a catalyst is used, it cures at medium temperature in a short time. Invented.

(A) an organic polyisocyanate, and (B)
A curable composition containing an organic compound having a hydroxyl group and / or an epoxy group and at least one selected from the group consisting of (C) metal halides, Lewis acids, organic tins, and quaternary ammonium salts.

The above-mentioned (B) is a curable composition which is glycidol or 4-hydroxymethyl-1-cyclohexene-1,2-epoxide.

The curable composition as described above, wherein (B) is (D) an organic compound having at least two hydroxyl groups or mercapto groups and (E) an organic compound having at least two epoxy groups. is there.

The curable composition further comprises (E) an organic compound having at least two epoxy groups.

The above-mentioned curable composition is treated at room temperature to 150 ° C.
Then, it is a curing method for obtaining a cured product by curing in 10 to 60 minutes.

A cured product obtained by curing the curable composition described above.

A sealing material containing the curable composition described above.

The present invention will be described in detail below. The organic polyisocyanate (A) is a main component of the curable composition of the present invention, and is a compound having at least one isocyanate group as a substituent. Specifically, 2,
4-tolylene diisocyanate, 2,6-tolylene diisocyanate (TDI), diphenylethane-4,4-
Diisocyanate (MDI) and modified products thereof,
1,5-naphthalene diisocyanate (NDI), tolidine diisocyanate (TODI), hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), xylene diisocyanate (XD)
I), 1,4-phenylene diisocyanate, transcyclohexane-1,4-diisocyanate, lysine diisocyanate, triphenylmethane triisocyanate, tris (isocyanatophenyl) thiophosphate, tetramethylxylene diisocyanate (TMXD
I), lysine ester triisocyanate, 1,6,1
1-undecane triisocyanate, 1,3,6-hexamethylene triisocyanate, bicycloheptane triisocyanate, trimethylhexamethylene diisocyanate (TMDI) can be mentioned, and each of these polyisocyanates can be used alone or in addition to two kinds. The above can also be used together. The skeleton of the organic polyisocyanate is preferably aromatic with high reactivity, and more preferably TDI or MDI.

The (A) organic polyisocyanate is
A urethane prepolymer produced by reacting a polyol and a polyisocyanate can be used. Here, the polyol is a general term for a polyhydroxyl compound having a structure in which a plurality of hydrogens of a hydrocarbon are substituted with a hydroxyl group, and examples thereof include ethylene oxide, propylene oxide, butylene oxide, and tetrahydrofuran. Is a product obtained by addition-polymerizing one kind or two or more kinds of alkylene oxides such as the above to a compound having two or more active hydrogens. As the compound having two or more active hydrogens, ethylene glycol,
Examples include propylene glycol, butanediol, diethylene glycol, glycerin, hexanetriol, trimethylolpropane, pentaerythritol, and polyether-based such as polytetramethylene glycol, polyethylene glycol, polypropylene glycol, polyoxypropylene glycol, and polyoxybutylene glycol. Polyols; Polyolefin polyols such as polybutanediene polyol and polyisoprene glycol; Adipate polyols; Lactone polyols; Polyhydric alcohols such as polyester polyols such as castor oil; Polyhydric phenols such as resorcinol and bisphenol can be used. is there. Each of these polyols can be used alone or in combination of two or more, but in any case, the weight average molecular weight of each polyol is 100 to 10,000, preferably 500 to 10,000. It is preferably about 5,000.

When the polyol and the polyisocyanate are reacted with each other, the ratio of the amounts of both is not more than 1.0 hydroxyl group of the polyol per one isocyanate group of the polyisocyanate, but is 0.4 to 0.6. Is preferred. As the reaction temperature and the reaction pressure, those used in the usual production of urethane rubber can be adopted, and a composition usable in the present invention by reacting a polyol and a polyisocyanate under a normal pressure at a reaction temperature of about 10 to 100 ° C. The urethane prepolymer which is one of the above can be produced.

The organic compound (B) having a hydroxyl group and / or an epoxy group, which is the main component of the curable composition of the present invention, has a hydroxyl group or a thiol group, an epoxy group, or a hydroxyl group and an epoxy group. There is something.
Here, the epoxy group is a general term for a portion of an ethylene oxide bond, and specific examples thereof include bisphenol A type epoxide, bisphenol F type epoxide, and phenol novolac type epoxide. The curable composition is preferably a bisphenol A type epoxide, more preferably glycidol having one hydroxyl group and one epoxy group in one molecule, or 4-hydroxymethyl-1-cyclohexene-1,2-epoxide. is there.

The metal halide (C), Lewis acid, organotin, and quaternary ammonium salt are necessary catalysts for curing the curable composition of the present invention. Specifically, as the metal halide, LiCl, LiBr,
LiI, NaCl, NaBr, NaI, KCl, KB
r and KI. As Lewis acid, BF ₃ , Zn
Examples thereof include Cl ₂ , SnCl ₄ , FeCl ₃ , and AlCl ₃ . Examples of the organotin compound include dibutyltin diacetate, dibutyltin dilaurate, dibutyltin mercurtide, dibutyltin thiocarboxylate, dioctyl mercaptide and dibutyltin dimaleate. As a quaternary ammonium salt, tetraethylammonium bromide, tetraethylammonium iodide, tetraethylammonium hydrogen sulfate, tetra-n-butylammonium bromide, tetra-n-butylammonium chloride, tetra-n-butylammonium iodide, tetrahydrogensulfate Examples include -n-butylammonium and tetra-n-butylammonium nitrate.

Among the catalysts described above, metal halides, quaternary ammonium salts, and organic tin are preferable for curing the curable composition of the present invention. Metal halides, quaternary ammonium salts NaI and KI, and tetra-n-butylammonium iodide salts are preferable, and KI is more preferable, because a cured product can be obtained at medium temperature in a short time. Further, the metal halide or the quaternary ammonium salt is easily dissolved in the compound having a hydroxyl group, and is therefore preferable for curing the curable composition of the present invention.

The main component of the curable composition of the present invention (D) is an organic compound having at least two or more hydroxyl groups or mercapto groups. Specific examples of the compound having two or more hydroxyl groups include ethylene. Mention may be made of glycols, trimethylolpropane and polyols.
As the curable composition, ethylene glycol and polyol are preferred, and polyol is more preferred. On the other hand, the compound having a mercapto group is a hydroxyl group,
It is a compound in which an OH group is replaced with a -SH group.

Specific examples of the organic compound having at least two epoxy groups (E), which is the main component of the curable composition of the present invention, include bisphenol A type epoxide, bisphenol F type epoxide, and phenol novolac type. Mention may be made of epoxides. As the curable composition, bisphenol A type epoxide and bisphenol F type epoxide are preferable, and bisphenol A type epoxide is more preferable.

From the above-mentioned (A) organic polyisocyanate, (B) an organic compound having a hydroxyl group and / or an epoxy group, and (C) a metal halide, a Lewis acid, an organic tin, and a quaternary ammonium salt. The curable composition containing at least one selected from the group consisting of and the cured product thereof will be described using the following general formula.

[Chemical 1] (A) TDI urethane prepolymer is used as the organic polyisocyanate, (B) a glycidol having a hydroxyl group and an epoxy group is used as an organic compound having a hydroxyl group and / or an epoxy group, (C) a metal halide, a Lewis acid, Organotin and KI are used as catalysts, which are quaternary ammonium salts, and they are mixed. The composition is cured by heating at medium temperature for a short time to eliminate tack on the surface and inside, and a cured product is obtained. The reaction between the hydroxyl group and the isocyanate group, and the reaction between the epoxy group and the isocyanate group both proceed. In the case of hydroxyl group and isocyanate group, urethane bond occurs,
In the case of an epoxy group and an isocyanate group, the reaction of forming an oxazolidone ring proceeds. In the cured product crosslinked with glycidol, a urethane bond and a bond forming an oxazolidone ring occur.

The organic compound having (B) a hydroxyl group and / or an epoxy group is (D) an organic compound having at least two hydroxyl groups or a mercapto group,
(E) A curable composition comprising an organic compound having at least two epoxy groups and a cured product thereof will be described. (A) As an organic polyisocyanate, TDI
Using a urethane prepolymer, (D) using diethylene glycol as an organic compound having at least two or more hydroxyl groups or mercapto groups, (E) at least 2
As the organic compound having one or more epoxy groups, a bisphenol A type epoxy resin is used, and (C) a metal halide, a Lewis acid, an organic tin, and KI as a catalyst which is a quaternary ammonium salt, and these are mixed. The composition is cured by heating at medium temperature for a short time to eliminate tack on the surface and inside, and a cured product is obtained. Also, in this curing reaction, bisphenol A
The type epoxy resin has an effect of controlling foaming. The cured product crosslinked with difunctional diethylene glycol and / or bisphenol A type epoxy resin has several bonds. The bifunctional diethylene glycol only crosslinked portion is crosslinked by two urethane bonds. Similarly, the cross-linking portion only by the bifunctional bisphenol A type epoxy resin is cross-linked by the bond forming the oxazolidone ring. Further, the diethylene glycol and the bisphenol A type epoxy resin generate an ether bond by a polymerization reaction. The ether bond causes crosslinking by the reaction of the terminal groups of diethylene glycol and bisphenol A type epoxy resin, which are connected to some of them, and the isocyanate groups of the urethane prepolymer. In this case, when the terminal group is a hydroxyl group, it is crosslinked by a urethane bond, and when the terminal group is an epoxy group, it is crosslinked by a bond forming an oxazolidone ring.

The above-mentioned (A) organic polyisocyanate,
(B) an organic compound having a hydroxyl group and / or an epoxy group, (E) an organic compound having at least two epoxy groups, and (C) a metal halide, a Lewis acid, an organic tin, and a quaternary ammonium salt. The curable composition by the mixture to which the catalyst is added, and its cured product will be described. (A) As an organic polyisocyanate, TDI
Using a urethane prepolymer, (B) an organic compound having a hydroxyl group and / or an epoxy group, a polyol having a hydroxyl group and an epoxy group, and (E) an organic compound having at least two epoxy groups,
A bisphenol A type epoxy resin is used, and (C) a metal halide, a Lewis acid, an organic tin, and KI are used as a catalyst which is a quaternary ammonium salt, and these are mixed. The composition is cured by heating at medium temperature for a short time to eliminate tack on the surface and inside, and a cured product is obtained. Further, in this curing reaction, the bisphenol A type epoxy resin has an effect of controlling foaming. The cured product crosslinked with a polyol and / or a bisphenol A type epoxy resin has some bonds. The cross-linking part with only polyol is 2
Crosslinked by two urethane bonds. Similarly, the cross-linking portion only by the bifunctional bisphenol A type epoxy resin is cross-linked by the bond forming the oxazolidone ring. Further, the polyol and the bisphenol A type epoxy resin generate an ether bond by a polymerization reaction. The ether bond causes cross-linking by the reaction between the end groups of the polyol and the bisphenol A type epoxy resin connected to some and the isocyanate group of the urethane prepolymer.
In this case, when the terminal group is a hydroxyl group, it is crosslinked by a urethane bond, and when the terminal group is an epoxy group, it is crosslinked by a bond forming an oxazolidone ring.

In curing by the above-mentioned crosslinking, (B) an organic compound having a hydroxyl group and / or an epoxy group,
(D) an organic compound having at least two or more hydroxyl groups or mercapto groups, and (E) a hydroxyl group, a mercapto group, or an epoxy group in an organic compound having at least two or more epoxy groups, and (A) an organic polyisocyanate A curing method in which the ratio of isocyanate groups is 0.5 to 1.5, preferably 0.7 to 1.2, more preferably 1.0.

(A) Organic polyisocyanate, (B) hydroxyl group and // which are the main components of the above-mentioned curable composition.
Alternatively, an organic compound having an epoxy group, (D) an organic compound having at least two or more hydroxyl groups or a mercapto group, (E) an organic compound having at least two or more epoxy groups, and a catalyst (C) a metal halide , A Lewis acid, an organotin, and a quaternary ammonium salt are mixed according to the above-mentioned combination, and the mixture is mixed at room temperature to 15
It is a curing method of obtaining a cured product by curing at 0 ° C. for 10 to 60 minutes. The curing temperature is preferably room temperature to 100 ° C, more preferably 70 to 80 ° C. The curing time is preferably 10 to 60 minutes, more preferably 10 to 60 minutes.
30 minutes.

In the above curing method, the catalyst (C) metal halide, Lewis acid, organic tin, and quaternary ammonium salt are contained in an amount of 1 to 20 mol%, preferably 1 to 20 mol% based on the isocyanate group content of the organic polyisocyanate (A). Is a curing method of 10 mol%.

In order to use the curable composition of the present invention as a sealing material, it is necessary to add an inorganic filler and a plasticizer in addition to the curable composition of the present invention. The purpose of compounding the inorganic filler is to reduce cost, improve physical properties, and adjust viscosity. Activity of the filler, particle shape, pH,
Depending on the presence or absence of surface treatment, it has a great influence on storage stability, curing speed, physical properties, and foaming, and it is necessary to be careful in determining the type and amount. Generally, calcium carbonate, talc,
Silica, carbon black, etc. are used. Plasticizers are used for adjusting viscosity and physical properties. Any plasticizer which is inert to isocyanate groups and has good compatibility without bleeding can be used. Generally, dioctyl phthalate, dibutyl phthalate, dioctyl adipate and the like are used. In addition, the above-mentioned sealing materials are used in factories (automobiles,
In order to use it as an adhesive in a building material line with low heat energy, it is necessary to further add an adhesion-imparting agent such as tempel resin, phenol resin or rosin resin.

The composition of the present invention comprises, in addition to the above-mentioned essential components, a curing catalyst, a filler, and a curing catalyst within a range that does not impair the effects of the present invention.
A plasticizer, a thixotropy-imparting agent, a pigment, a dye, an antioxidant, an antioxidant, an antistatic agent, a flame retardant, an adhesion-imparting agent, a dispersant, a solvent and the like may be added to the curable composition.

[0030]

The present invention will be described in detail with reference to the following examples. However, the present invention is not limited to this. The results are shown in Table 1 below. The TDI urethane prepolymer used here was synthesized by mixing trifunctional polypropylene glycol (PPG) and TDI so that (isocyanate group / hydroxyl group) was 2.15. The weight average molecular weight of PPG is 3,000. Example 1 5 g of TDI urethane prepolymer (2.1
Glycidol 0.1 g (NCO content 5% NCO content)
0.5 equivalent to the content, and potassium iodide (K
I) 0.05 g (10 mol% based on NCO content)
And were mixed in a flask. This composition is 8
At 0 ° C for 15 minutes, the tack on the surface and inside disappeared and the resin was cured.

[Example 2] Bisphenol A was added to 5 g of TDI urethane prepolymer (content of NCO of 2.15%).
Type (hereinafter abbreviated as bis A type) epoxy resin 0.45g
(1 equivalent to NCO content), 0.07 g of diethylene glycol (0.25 equivalent to NCO content), and 0.05 g of potassium iodide (KI) (10 mol% to NCO content) And were mixed in a flask.
The composition cured in an oven at 80 ° C. for 15 minutes with no tack on the surface or inside.

[Example 3] TDI urethane prepolymer 5 g (NCO content of 2.15%), bis A type epoxy resin 0.45 g (1 equivalent to NCO content) and 3
0.12 g of functional polyol (trade name PLACCEL305 (manufactured by Daicel Chemical Industries)) (based on NCO content,
0.33 equivalent) and 0.05 g of potassium iodide (KI)
(10 mol% with respect to NCO content) is mixed in a flask. The composition cured in an oven at 80 ° C. for 15 minutes with no tack on the surface or inside. The weight average molecular weight of the trifunctional polyol is 300 to 10,000.
Is preferable, and more preferably 300 to 3000.

[Example 4] TDI urethane prepolymer 5 g (2.15% NCO content) to 0.23 g of bis A type epoxy resin (0.5 equivalent to NCO content)
And glycidol 0.05 g (for NCO content,
0.25 equivalent) and 0.05 g of potassium iodide (KI)
(10 mol% with respect to NCO content) was mixed in a flask. The composition cured in an oven at 80 ° C. for 15 minutes with no tack on the surface or inside.

Comparative Example 1 5 g of TDI urethane prepolymer (content of NCO of 2.15%) and 0.1 g of bis-A type epoxy resin (0.23 equivalent to NCO content)
And 0.034 g (commercial name DMP-30 (manufactured by Kayaku Akzo)) of tertiary amine 2,4,6-tris (dimethylaminomethyl) phenol (5 m relative to NCO content).
ol%) in a flask. 130 of this mixture
A cured product was obtained by heating at ℃ for 4 hours.

[Table 1]

[0035]

EFFECTS OF THE INVENTION By using the curable composition of the present invention, it is possible to cure at medium temperature for a short time, and it can be used as an adhesive in a factory (automobile, building material) line with low heat energy.

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 4H017 AA04 AA24 AB03 AC03 AD06                 4J034 BA02 BA09 CA01 CA02 CA05                       CA32 CA34 CC26 CC52 CC61                       CC65 DK00 DK01 DK02 FA01                       HA01 HA06 HA07 HA08 HB02                       HB15 HC01 HC02 HC03 HC09                       HC11 HC12 HC13 HC16 HC22                       HC46 HC47 HC52 HC54 HC61                       HC63 HC64 HC65 HC66 HC67                       HC71 HC73 HD00 JA41 JA42                       KA00 KA01 KB02 KB04 KC02                       KC08 KC13 KC17 KC35 KD02                       KD12 KD21 KD24 KD25 KE01                       KE02 QD00 RA08 SA01 SA02                       SE01 SE03

Claims (7)

[Claims] 1. An organic polyisocyanate (A) and (B)
A curable composition containing an organic compound having a hydroxyl group and / or an epoxy group, and at least one selected from the group consisting of (C) a metal halide, a Lewis acid, an organic tin, and a quaternary ammonium salt. 2. The curable composition according to claim 1, wherein the (B) is glycidol or 4-hydroxymethyl-1-cyclohexene-1,2-epoxide. 3. The curing according to claim 1, wherein (B) is (D) an organic compound having at least two or more hydroxyl groups or mercapto groups and (E) an organic compound having at least two or more epoxy groups. Sex composition. 4. The curable composition according to claim 1, further comprising:
(E) A curable composition comprising an organic compound having at least two epoxy groups. 5. A curing method for obtaining a cured product by curing the curable composition according to any one of claims 1 to 4 at room temperature to 150 ° C. for 10 to 60 minutes. 6. A cured product obtained by curing the curable composition according to claim 1. 7. A sealing material containing the curable composition according to claim 1.