JPH05295079A - Production of epoxy resin - Google Patents

Abstract

PURPOSE:To obtain an epoxy resin having a low viscosity, containing flexible skeleton and giving a cured product having excellent physical properties by reacting an epoxidized isocyanate with a polymer having one or more hydroxyl groups or mercapto groups in the molecule. CONSTITUTION:The objective epoxy resin is produced by compounding (A) an epoxidized isocyanate of formula I to formula III with (B) a polymer containing one or more mercapto groups or OH groups in the molecule and having a number-average molecular weight of preferably 500-20,000 [e.g. polyethylene glycol or polysulfide of formula IV ((n) is 0-20)] at an isocyanato/(OH or mercapto) molar ratio [(NCO/(OH or SH)] of preferably 0.7-1.5 and reacting the components in the presence of a catalyst such as tin octylate at room temperature to 100 deg.C for 3-20hr.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a novel epoxy resin having a urethane bond. The epoxy resin produced by the method of the present invention is a coating material, an adhesive,
It is preferably used as a sealing material, a vibration damping material, an electric potting material, and the like.

[0002]

2. Description of the Related Art Epoxy resins are generally hard and brittle, and therefore have low peel strength when used as an adhesive. In addition, since cracks are likely to occur, they cannot be widely used for structural materials, coating materials and the like. Applications that require flexibility as well as elasticity,
For example, it can be said that it is essentially difficult to use a covering material for a concrete structure, a cushioning material, or a potting material at a portion where internal stress is applied because of its adhesion point.

To compensate for these drawbacks, there is a flexible epoxy resin, which is a resin having a flexible skeleton. Examples of the flexible epoxy resin include glycidyl ester type, polyoxyalkylene glycol type, bisphenol A propylene oxide addition type, urethane modified epoxy resin type, and polybutadiene modified type. Among these, urethane-modified epoxy resins are relatively easy to obtain, and some have been known so far, but those having elasticity have a drawback of high viscosity.

For example, as proposed in Japanese Patent Publication No. 62-53527, an epoxy resin obtained by reacting a polyether polyol with a diisocyanate to synthesize a urethane prepolymer and then reacting this with glycidol has a high viscosity. .. This method causes a problem in use because the viscosity increases due to the increase in the molecular weight due to the reaction between diisocyanate and the polyol. In order to reduce the viscosity, it is necessary to add many reactive diluents and the like, which causes deterioration of the physical properties of the cured product. In addition, the polyol may make it impossible to manufacture due to high viscosity or gelation. For example, epoxidation of a trifunctional compound having a polypropylene oxide skeleton has a high viscosity by this method and is difficult to produce.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for producing a low-viscosity (thio) urethane-modified epoxy resin having a flexible skeleton in terms of physical properties of the cured product.

[0006]

Means for Solving the Problems As a result of intensive studies to achieve the above object, the present inventors have found that a novel epoxy resin obtained by reacting an epoxidized isocyanate having a specific structure with a polymer having a hydroxyl group or a mercapto group It was found that even if the viscosity was low, the tear strength of the cured product was remarkably excellent, and the present invention was completed.

That is, according to the present invention, the following equations (1) to
There is provided a method for producing an epoxy resin, which comprises reacting at least one epoxidized isocyanate represented by (3) with a polymer having one or more hydroxyl groups or mercapto groups in the molecule.

[Chemical 2]

[0008]

[Structure] The structure of the present invention will be described in detail below, but it will be apparent that a more preferable embodiment of the present invention and the advantages based on it will be apparent.

[0009] Epoxy isocyanate of formula used as the starting materials in the epoxidation isocyanate present invention (1) are novel substances, their preparation are described in detail in Japanese Patent Application No. 4-96625 specification filed by the present applicant .. The epoxidized isocyanates of formulas (2) and (3) are also novel substances, but can be obtained by reacting tolylene diisocyanate with glycidol according to the above specification.

Polymer having hydroxyl group or mercapto group
Of the hydroxyl group or mercapto group which is another raw material used in over present invention that include one or more polymers in the molecule, the hydroxyl group-containing polymers, polyethylene glycol,
Polypropylene glycol, polytetrahydrofuran,
Polyether polyols such as copolymers of ethylene oxide and propylene oxide, hydroxyl-terminated polybutadiene, diene-based polyols such as hydrogenated hydroxyl-terminated polybutadiene, polyethylene adipate, polypropylene adipate, polyhexamethylene adipate, polyester polyols such as polybutylene adipate, Examples thereof include celluloses such as polyvinyl alcohol, methyl cellulose, ethyl cellulose, acetyl cellulose, hydroxyethyl cellulose and the like.

Examples of the mercapto group-containing polymer include the following polysulfides. HS (CH ₂ CH ₂ OCH ₂ OCH ₂ CH ₂ SS) _n CH ₂ CH ₂ OCH ₂ OCH ₂ CH ₂ SH (n is 0 to 20)

The number average molecular weight of the above-mentioned hydroxyl group-containing polymer or mercapto group-containing polymer is preferably 500 to 20,000 in consideration of the viscosity and flexibility of the obtained epoxy resin.

Reaction Method The reaction between the epoxidized isocyanate and the hydroxyl group- or mercapto group-containing polymer is carried out when the molar ratio of isocyanate group to hydroxyl group or mercapto group (NCO / OH, SH) is 0.1.
It is preferably 5 to 2.0, and particularly preferably 0.7 to 1.5 from the viewpoint of obtaining an epoxy resin excellent in appropriate viscosity and storage stability.

In the reaction, a known catalyst used for the reaction of isocyanate with a hydroxyl group or a mercapto group can be used. Specific catalysts include organic metal compounds such as tin octylate and dibutyltin dilaurate,
Preferable examples include tertiary amines such as 1,4-diaza-2,2,2-bicyclooctane, triethylamine, dimethylcyclohexylamine, diazabicycloundecane and diethylbenzylamine.

The reaction between the epoxidized isocyanate and the hydroxyl group- or mercapto group-containing polymer can be carried out by reacting in the presence or absence of an inert solvent at room temperature to 100 ° C. for 3 to 20 hours. Specific examples of usable inert solvents include solvents such as hexane, pentane, benzene, toluene, xylene, methylene chloride, chloroform, tetrahydrofuran, dioxane, acetone, and methyl ethyl ketone.

It is also possible to produce the epoxidized isocyanate by using a solvent, use it as it is as the epoxidized isocyanate-containing solution, and add the hydroxyl group- or mercapto group-containing polymer to carry out the reaction.

The reaction is carried out until the isocyanate groups have substantially disappeared, after which the solvent is removed if necessary to obtain the novel epoxy resin of the present invention.

Further, the above reaction can be carried out in the presence of a liquid epoxy resin. By doing so, a mixture of the novel epoxy resin produced by the method of the present invention and another type of liquid epoxy resin can be obtained in one operation, which is economical.

The liquid epoxy resin that can be used at this time may be any liquid epoxy resin at room temperature. For example, ethylene glycol diglycidyl ether, diethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexane glycol diglycidyl ether, vinylcyclohexene dioxide, bisphenol A diglycidyl ether, phenylglycidyl ether. Butyl glycidyl ether.

The new epoxy resin thus obtained usually has an epoxy equivalent of 500 to 5000, preferably 600 to 3000, and has a viscosity at room temperature of usually 5000 to 70,000 c.
ps is preferably 5000 to 40,000 cps.

Curing Method and Use The novel epoxy resin produced by the method of the present invention can be used alone, but other epoxy resins, diluents, pigments, fillers and other additives may be added as required. May be added. The curing reaction can be performed at room temperature or lower depending on the type of curing agent used. In addition, depending on the use, it may be heat-cured, or a catalyst may be used in combination to accelerate the curing. Examples of the curing agent include aromatic amines, aliphatic amines, alicyclic amines, polyamides, amino resins, acid anhydrides and aromatic modified polyamines. In particular,
When an aliphatic amine such as isophoronediamine or 1,3-bis (aminomethyl) cyclohexane is used, the curing reaction is quick and the workability is good. The compounding amount of the curing agent in the present invention is 0.1 to the epoxy group of the epoxy resin of the present invention.
An equivalence ratio of 1.2, preferably 0.5 to 1.0 is good.

The novel epoxy resin produced by the method of the present invention has a low viscosity, and its cured product has large tear strength and flexibility, so that it is used as a covering material for concrete structures,
It can be suitably used for applications such as cushioning materials and potting materials.

[0023]

EXAMPLES The present invention will be specifically described below with reference to examples.

Example 1 100 g of dried polytetrahydrofuran having a molecular weight of about 2000 and a hydroxyl value of 56.1 (corresponding to 2 hydroxyl groups per molecule) was added to the formula (1) containing epoxidized isocyanate as a main component. 24.82 g of the mixture of 1) to (3), dibutyltin dilaurate 0.0
1 g was added and stirred at 80 ° C. for 3 hours to obtain an epoxy resin. The obtained resin had an isocyanate group content of 0% and an epoxy equivalent of 1255. Next, 100 g of this resin
2.8 g of 1,3-bis (aminomethyl) chlorohexane
Was added and left in an oven at 100 ° C. for 1 hour to cure. The basic physical properties are shown in Table 1.

Example 2 100 g of dried polytetrahydrofuran having a molecular weight of about 3000 and a hydroxyl value of 37.4 (corresponding to 2 hydroxyl groups per molecule) was added to the formula (1) containing epoxidized isocyanate of the formula (1) as a main component. )-(3) mixture 16.5g and dibutyl tin dilaurate 0.01g were added, and it stirred at 80 degreeC for 3 hours, and obtained the epoxy resin. The resin obtained had an isocyanate group content of 0% and an epoxy equivalent of 1
It was 758. Next, add 100 g of this resin to 1,3-
1.9 g of bis (aminomethyl) cyclohexane was added,
It was left to cure in an oven at 100 ° C. for 1 hour. The basic physical properties are shown in Table 1.

Example 3 100 g of dried hydroxyl-terminated polybutadiene having a hydroxyl value of 44.2 (corresponding to 2 hydroxyl groups per molecule) was added to 1 g of epoxidized isocyanate 1 of the formula (1).
9.6 g and 0.01 g of dibutyltin dilaurate were added and stirred at 80 ° C. for 3 hours to obtain an epoxy resin. The resulting resin had an isocyanate group content of 0% and an epoxy equivalent of 1580. Next, 100 g of this resin
2.8 g of 3-bis (aminomethyl) cycloxane was added and left in an oven at 100 ° C. for 1 hour to cure.
The basic physical properties are shown in Table 1.

(Example 4) TDI (80% of 2,4-body was added to 15 g of neopentyl glycol diglycidyl ether).
13.7 g) was added, 0.05 g of dibutyltin dilaurate was added, and the mixture was ice-cooled and then glycidol 5.85 was added.
g was slowly added dropwise. After stirring for 30 minutes, the hydroxyl value is 44.
100 g of the dried hydroxyl-terminated polybutadiene of 2 was added and reacted at 80 ° C. for 4 hours. The obtained resin had an isocyanate group content of 0% and an epoxy equivalent of 846. Next, 6.0 g of isophoronediamine was added to 100 g of this resin, and the mixture was left to cure in an oven at 100 ° C. for 1 hour. The basic physical properties are shown in Table 1.

Example 5 Dry trifunctional propylene oxide-ethylene oxide copolymer 10 having a molecular weight of about 6000 and a hydroxyl value of 28 (corresponding to 3 hydroxyl groups per molecule).
02.4 g of epoxidized isocyanate of formula (1) 12.4
g, dibutyltin dilaurate 0.01 g,
The mixture was stirred at 0 ° C for 3 hours to obtain an epoxy resin. The obtained resin has an isocyanate group content of 0% and an epoxy equivalent of 230.
It was 0. Next, 1.5 g of isophoronediamine was added to 100 g of this resin, and the mixture was left in an oven at 100 ° C. for 1 hour to be cured. The basic physical properties are shown in Table 1.

EXAMPLE 6 35.0 g of neopentyl glycol diglycidyl ether was added with 8 parts of TDI (2,4-form).
Dissolve 35.7 g (containing 0%), add 0.05 g of dibutyltin dilaurate, cool with ice, and then add glycidol 1
5.2 g was slowly added dropwise, and after stirring for 30 minutes, the molecular weight was 10
1 of polysulfide of 00 (Toray Thiokol, LP3)
00g and triethylamine 0.05g were added, and it was added at 60 ° C for 4
Reacted for hours. The obtained resin had an isocyanate content of 0% and an epoxy equivalent of 482. 2.5 g of 1,3-bis (aminomethyl) cyclohexane on this resin
Was added and left in an oven at 100 ° C. for 1 hour to cure.

Comparative Example 1 100 g of dried hydroxyl-terminated polybutadiene having a hydroxylation of 44.2 was added with TDI (2,4-).
13.8 g (containing 80% of the body) and 0.01 g of dibutyltin dilaurate were added, and the mixture was reacted at 80 ° C. for 4 hours, then 5.8 g of glycidol was added, and the mixture was further reacted for 4 hours. Next, add 1,3-bis (aminomethyl) to this resin.
2.8 g of cyclohexane was added and left in an oven at 100 ° C. for 1 hour to cure.

(Comparative Example 2) Molecular weight 2000, hydroxyl value 5
To 100 g of dried polytetrahydrofuran of 6.1 (corresponding to two hydroxyl groups per molecule), 17.4 g of TDI (containing 80% of 2,4-form) and 0.01 g of dibutyltin dilaurate were added, and the mixture was heated at 80 ° C. for 4 hours. After the reaction, 7.42 g of glycidol was added, and the reaction was further continued for 4 hours. Next, add 1,3-bis (aminomethyl) to this resin.
2.8 g of cyclohexane was added and left in an oven at 100 ° C. for 1 hour to cure.

The results of the above Examples and Comparative Examples are shown in Table 1. Each physical property was measured by the following methods. JIS hardness: Made according to JIS K6301 Tensile strength: Made according to JIS K6301 Tensile elongation: Made according to JIS K6301 Tear strength: Made according to JIS K6301

[0033]

[Table 1]

[0034]

EFFECTS OF THE INVENTION The production method of the present invention provides a novel (thio) urethane-modified epoxy resin having a viscosity lower than that of the conventional method. The physical properties of the cured product thereof are excellent particularly in tear strength and flexibility. Is also excellent.

Claims (1)

[Claims] 1. An epoxy resin characterized by reacting at least one epoxidized isocyanate represented by the following formulas (1) to (3) with a polymer containing at least one hydroxyl group or mercapto group in the molecule. Production method. [Chemical 1]