JPH01138221A - Moisture-curable one-package epoxy resin composition and method for curing it - Google Patents

Abstract

PURPOSE:To obtain an one-pack epoxy resin compsn. having excellent storage stability and being curable at ordinary temp. an which is comprised of a polyepoxy compd. and a specified aminosilane compd. CONSTITUTION:The title compsn. comprises a polyepoxy compd. having 2 or more epoxy groups in its molecule (e.g., bisphenol A glycidyl ether type epoxy resins, their deriv., etc.) and an aminosilane compd. having one or more N-Si bond in the molecule which can be easily hydrolyzed with moisture to regenerate a prim. or a sec. amine (which is obtd. by condensation of various alip., alicyclic or arom. prim. or sec. amine compd. and trimethylchlorosilane, e.g., a reaction of formula I or by condensation of the amine compd. and hexamethyl silazane, e.g., a reaction of formula II or III). The title compsn. has excellent storage stability, is cured with moisture in an atmosphere at ordinary temp. and is used for adhesives, paints, coating materials, sealing materials for electronic parts, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to epoxy resin compositions. For more details,
The present invention relates to a novel one-component epoxy resin composition that has excellent storage stability and is cured by atmospheric moisture at room temperature.

Epoxy resins have excellent properties such as adhesiveness, durability, corrosion resistance, strength, and electrical insulation, and are therefore used in a wide variety of applications, including adhesives, paint coatings, casting materials, and laminated materials.

However, most of them are two-component. Therefore, in storage, the epoxy resin base and curing agent are stored separately, and when used, they are mixed, which is inconvenient to store and handle, and problems such as mixing errors and poor mixing are likely to occur.

In addition, work efficiency is poor because the usable time after mixing is limited. Furthermore, special care must be taken when using curing agents that are harmful to the human body.

In order to eliminate these drawbacks, many proposals have been made regarding single-wave epoxy resins. For example, BF
Epoxy resins in which latent curing agents such as triamine complexes, dicyandiamide, imidazole compounds, and organic acid hydrazides are blended have been proposed. However, materials with excellent storage stability after mixing must be heated to high temperatures and cured. On the other hand, those that harden with slight heating have low storage stability and are of little practical use.

Various methods for improving this point have been proposed (Japanese Unexamined Patent Publication No. 1988-
No. 55970, JP-A-59-27914, JP-A-59
-59720). These improved methods improve storage stability, but all require heating for curing and cannot be cured at room temperature.

As a latent curing agent of the room temperature curing type, a ketoimine (ketimine) or aldimine curing agent, which is obtained by reacting an amine with a ketone or an aldehyde, is known as shown in the following formula.

11□N -R-N 11□ + 2 Ctl+C0C
) I3 □ However, when these curing agents and epoxy resins are mixed, a reaction occurs gradually even in a sealed container at room temperature, resulting in gelation after several hours to several days, making it impossible to obtain desired storage stability.

As described above, all of the conventionally proposed curing agents for one-component epoxy resins have had practical difficulties. Therefore, there has been a desire for a one-component epoxy resin composition that has excellent storage stability and can be cured at room temperature upon use. The present invention improves upon the above-mentioned drawbacks of conventional wave-type epoxy resin curing agents.

The present invention is characterized by the use of an epoxy compound having two or more epoxy groups in one molecule, and an N-
A moisture-curable one-component epoxy resin composition containing an aminosilane compound containing one or more Si bonds in one molecule, and this composition is characterized by containing various additives as necessary. This is a moisture-curable liquid epoxy resin composition.

If necessary, an inert solvent, a plasticizer, a filler, a pigment, a thickener or a thixotropy agent, a stabilizer, a catalyst, etc. can be used in combination with the present composition.

Another feature of the invention is a method of curing an epoxy compound in the presence of a silicon compound capable of being hydrolyzed by moisture to regenerate primary or secondary amines.

In general, the present latent curing agent is extremely susceptible to hydrolysis, and moreover, the amine is regenerated by moisture in the air without producing harmful by-products. If the present latent curing agent and various epoxy group-containing compounds are mixed and stored in a sealed container in a moisture-free state, the mixture can be stored stably.

When this mixture is exposed to the atmosphere, the latent curing agent in the mixture is first hydrolyzed by moisture in the atmosphere to regenerate the amine, and then this amine reacts with the epoxy group to form an epoxy compound. harden.

The epoxy resin used in the present invention is not particularly limited as long as it is a polyepoxy compound having two or more epoxy groups in one molecule. For example, bisphenol A glycidyl ether type epoxy resin and its derivatives, glycerin glycidyl ether type epoxy resin, polyalkylene oxide glycidyl ether type epoxy resin, phenol novolac glycidyl ether type epoxy resin,
Examples include dimer acid glycidyl ester type epoxy resin, bisphenol F glycidyl ether type resin, alicyclic type epoxy resin, and the like.

Mixtures of the epoxy resins mentioned above and mixtures with monoepoxy compounds to reduce the viscosity of the epoxy resins can also be used.

Next, the aminosilane compound, which is the latent curing agent used in the present composition, is produced by hydrochloric acid condensation of various aliphatic, alicyclic, and aromatic primary or secondary amine compounds with trimethylchlorosilane, or by hexachlorosilane condensation with trimethylchlorosilane. Obtained by deammonia condensation with methylsilazane, etc.

(C2Hs)+N R-N 112-tei (CH3)3SjCIR-NHSi(
CH3)3◆(cz■5)3N・HCI ・-(1)
28NH5j (CH3) 30N83 ↑ -(
2) The amines include various primary or secondary amines, such as aliphatic alkylamines, 5-alkylene diamines; alicyclic mono- or diamines: aromatic mono- or diamines; nitrogen-containing heterocyclic compounds (the nitrogen atom is bonded to a hydrogen atom). Put the aminosilane compound into the air! When exposed to S, the aminosilane compound is easily hydrolyzed by moisture even at temperatures below room temperature, and the original amine is regenerated.

It is known that this regenerated amine compound can cure epoxy resins at room temperature.

Even if the aminosilane compound is mixed with an epoxy resin at room temperature, the mixture can be stored stably. Mixtures using aliphatic or alicyclic secondary amines or reactants with aromatic amines are particularly stable and can be stored for long periods of time.

Application fields of the room-temperature, moisture-curable, liquid-volume epoxy resin composition of the present invention include adhesives, paints, coating materials, and sealants for electronic components.

In the present invention, if necessary, solvents such as ethyl acetate, methyl ethyl ketone, toluene and xylene, plasticizers such as dioctyl phthalate and tricresyl phosphate, n-
Reactive diluents such as butyl glycidyl ether and phenyl glycidyl ether; fillers such as calcium carbonate, talc, mica, and aluminum oxide; thixotropic agents such as colloidal silica and castor oil-based thickeners; Additives such as foaming agents, leveling agents, tackifiers, and antioxidants can also be used in combination.

Next, the present invention will be explained with reference to Examples, but the present invention is not limited thereto.

In addition, in the examples, parts represent parts by weight.

Synthesis Example 1 m-xylene diamine 13 was placed in a reaction vessel equipped with a reflux condenser, a stirrer, a dropping device, a nitrogen gas inlet, and a thermometer.
6.1 parts of hexamethyldisilazane, 193'□X7 parts, and 6.6 parts of ammonium sulfate were added and heated in a nitrogen gas stream. Ammonia gas began to be generated when the liquid temperature was around 70°C, and reflux started at 102°C. After refluxing for 3 hours, the liquid temperature reached 130°C. - After cooling, 33 parts of trimethylchlorosilane was added dropwise, and the mixture was heated again. The IR of the reaction solution was measured, and the reaction was continued until the absorption of the primary amine at 3300 cm-' disappeared and a single absorption of the secondary amine at 3400 c+s-' was obtained. After filtering the reaction mixture, the filtrate was distilled to give a boiling point of 282-287°C, with no absorption of primary amines by IR.
174 parts of a colorless transparent liquid having a sharp absorption of secondary amine at 3400 cm-' was obtained.

When this liquid was hydrolyzed by adding water and subjected to gas chromatography [FfD, oven temperature 200°C], the production of trimethylsilanol was quantitatively confirmed, confirming that m-xylene diamine was regenerated. did.

Synthesis Example 2> In a reactor similar to Synthesis Example 1, 3.9-(3-aminopropyl)-2,4,8,10-tetrooxapyro(5,
5) Undecane [spiroacetal diamine-ATU manufactured by Ajinomoto ■] 1164.6 parts of hexamethyldisilazane and 3.1 parts of trimethylchlorosilane were added, and the mixture was heated and stirred while flowing nitrogen gas. Liquid temperature 8
Ammonia gas begins to be generated around 5℃, and the temperature rises to 125℃.
Reflux has begun. 9 until the absorption of primary amine at 1600 cm-' and 3350 cm-' disappears when measuring IR.
Reflux was continued for an hour. The liquid temperature at this time was 138°C.

After that, the reflux condenser was removed, excess hexamethyldisilazane was distilled out of the system, and a pale yellow viscous substance with no absorption of primary amines measured by IR measurement and a sharp absorption of secondary amines at 3400 cm-' was obtained. 243 parts of a viscous liquid were obtained.

When this liquid was hydrolyzed by adding water and tested by gas chromatography, the production of trimethylsilanol and hexamethyldisiloxane was quantitatively confirmed, and it was confirmed that the raw material diamine-ATU was regenerated.

Synthesis Example 3 50.4 parts of trimethylchlorosilane was placed in the same reaction vessel as in Synthesis Example 1, nitrogen gas was passed through it, and the mixture was stirred while cooling the outside with ice water. A solution of 19.9 parts of piperazine dissolved in 47.0 parts of triethylamine and 110 parts of chloroform was dropped into the reaction vessel from the dropping funnel over 1 hour while maintaining the liquid temperature at 9 to 13°C. After filtering the reaction mixture, the filtrate was distilled under atmospheric pressure while flowing nitrogen gas until the boiling point was 18.
20.0 parts of a colorless transparent liquid with no secondary amine absorption was obtained at 5 to 196°C and around 3400 crn-' in IR.

When this liquid was hydrolyzed by adding water and tested by gas chromatography in the same manner as in Synthesis Example 1, the production of trimethylsilanol and hexamethyldisiloxane was quantitatively confirmed, confirming that piperazine was regenerated. .

<Synthesis Example 4> 89.1 parts of diaminodiphenylmethane, 109.0 parts of hexamethyldisilazane and 1.1 parts of trimethylchlorosilane were placed in the same reaction vessel as in Synthesis Example 1, and stirred and heated while flowing nitrogen gas. did. Ammonia gas began to be generated when the liquid temperature was around 76°C, and reflux started at 125°C. Refluxing was continued for 8 hours until the primary amine was no longer absorbed at 3450 cm-' by IR. The final liquid temperature was 177℃
Met. After that, the flow condenser was removed, excess hexamethyldisilazane was distilled out of the system, and 3450'
cm-,' has no absorption of primary amine, 3400cl'
146.2 parts of a pale brown transparent viscous liquid with sharp absorption of secondary amine was obtained.

When this liquid was hydrolyzed by adding water and tested by gas chromatography in the same manner as in Synthesis Example 1, the production of trimethylsilanol and hexamethyldisiloxane was quantitatively confirmed, indicating that diaminodiphenylmethane was regenerated. confirmed.

<Example 1> While flowing nitrogen gas into a container equipped with a stirrer, a bisphenol A type epoxy resin having an epoxy weight i of 172 to 178 (Epicoat 82 manufactured by Yuka Shell Epoxy Co., Ltd.) was added.
5) 70 copies and a synthesis example! After adding 28 parts of the reaction product obtained in step 1 and mixing thoroughly, the mixture was defoamed under reduced pressure to obtain a moisture-curable one-component epoxy resin composition.

The shear adhesive strength of the composition was tested using zinc steel plates, stainless steel plates, FRP, surface-treated aluminum plates, and glass as bonded materials.

A storage stability test was also conducted on the composition in a sealed container. The results are shown in Table-2.

<Example 2, 3.4> The same procedure as in Example 1 was used except that the aminosilane latent curing agent of Synthesis Example 1 used in Example 1 was substituted with each predetermined amount of the latent curing agent of Synthesis Examples 2 and 3.4. A moisture-curable, corrugated epoxy resin was prepared.

Its composition is shown in Table 1.

Further, the adhesion test results of the composition of Example 2.3 are shown in Table 2, and the coating test results of Example 4 are shown in Table 3.

Table-1 Table-2 *Destruction of material to be adhered (Note) 1) Curing time is the time required to reach the tensile shear adhesive strength of wood of 30 kgf/cm2 under standard conditions (20°C-60% RH).

2) The test specimen for tensile shear adhesive strength is 14 in the standard state.
Tested after hardening soil for days.

3) Storage stability is determined by sealing the resin materials shown in Table 1 and storing them at 50℃7.
The condition was observed after several days, and those in good condition were marked with an O mark.

Next, the composition of Example 4 was applied onto the mortar to a thickness of 211111 mm.
I applied it and cured it. A hard, glossy and smooth coating film was obtained.

Table 3 shows the curing time of the coating film under standard conditions and the test results of the coating film cured after being left to stand for 14 days under standard conditions.

Table 3 [Note] l) Curing time is the time when the coating film does not deform even if you press it strongly with your fingertips after application under standard conditions (dry/rue time) 2) Heat resistance test is after curing the coating film for 14 days and then heating it to 100℃ After heating for 7 days, the film was returned to room temperature and the pencil hardness of the coating film was measured.

3) For the water resistance test, test specimens after curing similar to (2) were tested for 50
After standing in warm water at ℃ for 7 days, it was dried and the pencil hardness was measured.

4) For the alkali resistance test, the same cured coating film as in (2) was immersed in a saturated aqueous solution of slaked lime at 20°C for 7 days, and then measured in the same manner as before.

5) Solvent resistance test was carried out in the same manner as before after immersing the cured test specimen in toluene at 20° C. for 7 days in the same manner as in (2).

6) In the adhesion test, mortar was used as the material to be adhered, and after curing the specimen at 20° C. for 4 days, a tensile shear test was conducted, but the mortar material was destroyed.

7) In the storage stability test, the composition of Example 4 was placed in a closed container.
A storage test was conducted at 20°C, and it was stable even after 6 months.

Claims (1)

[Claims] 1. A polyepoxy compound having two or more epoxy groups in one molecule, and an N- compound that can be hydrolyzed by moisture to regenerate primary or secondary amino groups. 1 Si bond
A moisture-curable one-component epoxy resin composition containing one or more aminosilane compounds in the molecule. 2. Curing the epoxy compound in the presence of an aminosilane compound containing one or more N-Si bonds in each molecule that can be hydrolyzed by moisture to regenerate primary or secondary amino groups. Method.