GB2088859A - Polyglycidyl compounds and method for production thereof - Google Patents

Abstract

A novel polyglycidyl compound useful in the preparation of hardened epoxy resins having excellent adhesion, heat resistance and strength has the general formula: <IMAGE> The polyglycidyl compound may be produced by reaction of an epihalohydrin with an appropriate triamine and treatment of the reaction product with a base.

Description

SPECIFICATION Novel polyglycidyl compounds and method for production thereof The present invention relates to novel polyglycidyl compounds and a method for producing same.

More particularly, it relates to polyglycidyl compounds useful especially as polyfunctional epoxy resins and a method for producing same.

Recently, use of polyfunctional epoxy resins as matrix resins for composite materials such as carbon fiber reinforced composite materials has attracted attention and development of the epoxy resins more excellent in adhesion, heat resistance and strength has been demanded.

The inventors have made intensive researches on various derivatives of 1,3,5tris(aminomethyl)benzene (sometimes referred to as "MTA" hereinafter) and 1,3,5- tris(aminomethyl)cyclohexane (sometimes referred to as "H6MTA" hereinafter). As a result, it has been found that polyglycidyl derivatives of these triamines have excellent properties as polyfunctional epoxy resins.

That is, the present invention relates to polyglycidyl compounds represented by the general formula [I]:

(wherein

represents

of

) and a method for producing polyglycidyl compounds represented by the general formula tali:

(wherein

represents

or

), which comprises reacting an epihalohydrin with a triamine represented by the general formula:

(wherein

has the same meanings as defined above) and then treating the reaction product with an alkali.

In the accompanying drawings, Fig. 1 and Fig. 2 show infrared absorbing spectrum of the product obtained in Example 1 and Example 2, respectively.

The compound [I] of the present invention can be produced by reacting 1 ,3,5-tris(aminomethyl) benzene (MTA) or 1 ,3,5-tris(aminomethyl) cyclohexane (H6MTA) with an epihalohydrin, especially, epichlorohydrin and thereafter subjecting the reaction product to dehydrohalogenation treatment in the presence of an alkali. The starting materials MTA and H6MTA may be produced by the methods as disclosed in Japanese Patent Applications No. 67169/79 and No. 67170/79. That is, MTA can be produced by reducing, under the presence of a catalyst such as Raney nickel, a starting material of 1 ,3,5-tricyanobenzene obtained by ammoxydation of mesitylene. H6MTA can be produced by further reducing aromatic ring of the MTA under the presence of a reducing catalyst. H6MTA can also be obtained directly from 1 ,3,5-tricyanobenzene by reducing cyano groups and aromatic ring thereof.

Thus obtained MTA or H6MTA is first reacted with an epihalohydrin. This addition reaction may be carried out in accordance with known methods. For instance, the epihalohydrin is used preferably in an excess amount with respect to MTA or H6MTA, which is ordinarily 6 to 20 moles per 1 mole of these triamines. Reaction temperature is preferably within the range of about 20 to 60"C. These starting materials may be reacted without solvents, but the reaction may also be carried out in solvents such as organic solvents, water and the like to prevent abrupt exothermic reaction. Such addition reaction of the first stage will generally be completed within 2 to 5 hours although it depends on reaction conditions.

Then, an alkali is allowed to act on thus obtained epihaiohydrin addition products to carry out dehydrohalogenation reaction thereby to bring about ring closure to form epoxy groups. Alkali metal hydroxides such as sodium hydroxide, potassium hydroxide or aqueous solutions thereof may be suitably used as alkalis for the ring closure reaction. Generally, the alkalis are used in an excess amount.

After completion of the reaction, excess epihalohydrin and, if necessary, solvents are distilled out under reduced pressure. To the obtained reaction product is added an organic solvent such as benzene, toluene or xylene. Insoluble matter is filtered off and filtrate is washed several times with water or an aqueous sodium chloride solution. Then, the organic solvent is distilled out to obtain an objective product.

The polyglycidyl compounds of the present invention represented by the general formula [I] are especially useful as epoxy resins which provide hardened products having excellent characteristics. For example, the compounds of the present invention are liquid so that they are convenient for working.

Moreover, they can be hardened with known hardening agents. Examples of such hardening agents are aliphatic or aromatic acid anhydrides such as maleic anhydride, succinic anhydride, tetrahydrophthalic anhydride, hexahydrnphthalic anhydride, 3,6-endomethylenetetrahydrophthalic anhydride, dodecenylsuccinic anhydride, phthalic anhydride, etc., aliphatic or aromatic polyamines such as monoethylamine, n-propylamine, iso-propylamine, n-butylamine, hexylamine, benzylamine, ethylenediamine, aniline, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylether, 4,4'diaminodiphenyl sulfone, etc., aniline resin, polyamide resin, imidazoles, mercaptans, BF3 compounds, etc.Furthermore, the polygiycidyl compounds of the present invention have seif-hardening property and can be characteristically hardened without hardening agents.

The hardened products thus obtained have excellent adhesive property and heat resistance and high strength. When the compounds of the present invention are used as epoxy resins, there may be optionally added thereto compounding agents such as extenders, reinforcing agents, fillers, pigments, etc. Furthermore, if necessary, other known epoxy resins may be blended with the present compounds.

When the polyglycidyl compounds of the present invention are used as epoxy resins, the compounds, have excellent characteristics as mentioned above and so can be used as surface treating agents for various fibres such as carbon fiber and as matrix resins of various fiber reinforced resins, and moreover, as crosslinking agents or modifiers for acrylic resins and polyester resins. Furthermore, they are useful as stabilizers for unsaturated polyester resins.

Furthermore, the polyglycidyl compounds of the present invention are excellent in adhesive property and can be bonded to polypropylene films under specific conditions to which the commercially available epoxy resins cannot be bonded.

Reference Example 1 Preparation of 1 ,3,5-tricyanobene 18.2 parts of vanadium pentoxide was added to 1 50 parts of a 33% aqueous solution of oxalic acid and the mixture was heated to about 1 000C on a water bath to dissolve vanadium pento,tide. The solution was referred to as solution A. A solution obtained by dissolving 20 parts of chromium oxide (VI) in 1 50 parts of a 33S/o aqeous solution of oxlaic acid as mentioned above was referred to as solution B. Solutions A and B were homogeneously mixed.

To this mixed solution was added 300 parts oi anatase type titanium oxide powder burned at 8000C and water was evaporated therefrom while they were maced. Thus obtained wet slurry was molded by an extruder into a cylindrical shape having a diameter of 4 mm and a length of 5 mm. Thus obtained molded products were dried at 1 000C for 15 hours and thereafter burned at 5000C for 4 hours in air to obtain a catalyst.

About 200 ml of thus obtained catalyst was packed in an ordinary fixed bed reactor and a mixed gas consisting of 0.5 mole % of mesitylene, 7 mole ,6 of ammonia and 92.5 mole % of air was reacted under normal pressure at a space velocity of 1000 hr-1 (at normal temperature and pressure) while maintaining the temperature of medium in bath at 3600C to obtain 1 ,3,5-tricyanobenzene (MTN) in a yield of 51.2 mole %.

Reference Example 2 Preparation of 1 ,3,5-tris(aminomethyl) benzene 1 5 g of 1 ,3,5-tricyanobenzene (MTN) was charged into a magnetically stirring type autoclave having a 300 ml capacity together with 1 5 g of Raney nickel-chromium catalyst (atomic ratio : Ni : Cr = 49 :1), 27 ml of methanol, 63 ml of m-xylene and 0.18 g of sodium hydroxide. Hydrogen was injected thereinto under an initial pressure of 100 kg/cm2G and reaction was effected at 1 000C to cause absorption of 0.59 mole of hydrogen for 35 minutes. The catalyst was filtered oW and the solvent was distilled out. Then, distillation under reduced pressure was effected to obtain 12.8 g of colorless crystal of 1 ,3,5-tris(aminomethyl) benzene (MTA).

The product had a melting point of 49 to 51 C and a boiling point of 136 to 1 390C/0.4 mmHg.

Reference Example 3 Preparation of 1 ,3,5-tns(aminomethyl) cyclohexane.

30 g of 1 ,3,5-tris(aminomethyl) benzene (MTA) obtained in Reference Example 2 together with 3 g of 5% ruthenium-alumina catalyst (manufactured by Japan Engelhard Co., Ltd.), 60 g of water and 0.75 g of sodium hydroxide were charged in a magnetically stirring type autoclave having a 300 ml capacity. High pressure hydrogen was injected thereinto under an initial pressure of 1 20 kg/cm2G and reaction was effected at 11 50C for 25 minutes to cause adsorption of 0.61 mole of hydrogen.

The catalyst was filtered off and the solvent was distilled out. Thereafter, distillation under reduced pressure was carried out to obtain 26.8 g of 1 ,3,5-tris(aminomethyl) cyclohexane (H6MTA). This H6MTA was a colorless and transparent liquid of low viscosity which had a boiling point of 127 to 1280C/I mmHg.

Reference Example 4 Preparation of 1 ,3,5-tris(aminomethyl)cyclohexane In a magnetically stirring type autoclave having a 300 ml capacity were charged 20 g of 1 3,5- tricyanobenzene obtained in Reference Example 1 together with 80 ml of 25% aqueous ammonia, 300 mg of sodium hydroxide and 4 g of commercially available 5% rhodium-alumina catalyst and reaction was effected at 1 050C for 70 minutes under high pressure hydrogen having an initial pressure of 120 kg/cm2 to result in absorption of 0.95 mose of hydrogen to obtain H6MTA in which both the nitriles and the nucleus were reduced, in a yield of 45%.

EXAMPLE 1 In a 2 1 four-necked flask provided with a stirrer, a hot dropping funnel and a thermometer were charged 616 g of epichlorohydrin and 32.7 g of water and they were warmed to 350C with stirring. To this solution was dropped 100 9 of 1 ,3,5-tris(aminomethyl)benzene molten at 530C over a period of about 1.5 hour. Since violent heat generation occurs simultaneously with initiation of dropping of 1,3,5tris(aminomethyl)benzene, the flask was cooled and reaction temperature was kept at 35 to 400 C.

Reaction was effected for further 3 hours at the same temperature and thereafter 320 g of 50% aqueous NaOH solution was dropped thereto over a period of about 25 minutes keeping the temperature at 35 to 400 C.

Then, excess epichlorohydrin and water were removed at 400C over a period of 5 hours under a reduced pressure of 10 mmHg to 2 mmHg using a rotary evaporator to obtain a mixture of an oily material and a white crystal. To the mixture was added 600 ml of toluene cooled with ice and then the mixture was filtered. The filtrate was once washed with 100 ml of 3% aqueous NaCI solution and then washed again with 50 ml of water. Toluene was distilled out under a reduced pressure of 10 mmHg to obtain 245 g of slightly yellow transparent liquid which had a viscosity of 11 ,350 centipoises (250C) and an epoxy equivalent of 93.1 (theoretical value 83.6).

Elementary analysis C% H% N% Calcd: 64.65 7.84 8.38 Found: 64.36 7.81 8.11 IR absorption spectrum of the product is shown in Fig. 1. Measurement of NMR spectrum (CDCl3) of the product showed that a signal of singlet due to proton of the aromatic ring appeared at 7.22 ppm and a signal of complicated multiplet due to the other protons appeared at 2.2 to 4.1 ppm and the intensity ratio was 1 to 12.1. From these analytical values and spectra it was confirmed that the product was N,N,N',N',N",N"-hexaglycidyl-1 ,3,5-tris(aminomethyl)benzene.

EXAMPLE 2 Reaction procedure of Example 1 was repeated except that 100 g of 1,3,5tris(aminomethyl)cyclohexane was substituted for 1 ,3,5-tris(aminomethyl)benzene used in Example 1 and 593 g of epichlorohydrin, 32 g of water and 306 g of 50% aqueous solution of sodium hydroxide were used, whereby 227 g of a colorless and transparent liquid was obtained. The product had an epoxy equivalent of 95.5 (theoretical value 84.6) and a viscosity of 9,183 centipoises (250C).

Elementary analysis C% H% N% Calcd: 63.88 8.93 8.28 Found: 63.97 8.94 8.02 IR spectrum of the product is shown in Fig. 2. Furthermore, measurement of NMR spectrum (CDCl3) showed complicated multiplet spectrum at 0.2 to 4.1 ppm composed of the peculiar absorption pattern due to proton of skeleton of H6MTA which overlapped the signal due to proton of glycidyl. It was confirmed therefrom that the product was N,N,N',N',N",N"-hexaglycidyl-1 3,5 tris(aminomethyl)cyclohexane.

Experimental Examples 1-13 The polyglycidyl compounds synthesized in Examples 1 and 2 known epoxy resins were hardened with diaminodiphenylmethane (DMM), methyl nadic anhydride (MNA) or a polyamide by using the conventional procedures. The mechanical and thermal properties of the cast sheet prepared were measured and adhesion test was also carried out. The results are shown in Tables. The hardening was carried out by stepwise elevation of temperature.

TABLE 1

Heat distortion *3 Hardening *2 temperature Adhesion Experimental agent Hardening of cast sheet tp polyester Examples Epoxy resins DDM conditions ASTM D-648 film 1 Polyglycidyl compound obtained 59.3 A more than in Example 1 phr 200 C 2. # 2 Polyglycidyl compound obta ined 58.6 A more than in Example 2 200 C # 3 Tetrafunctional eposy resin *1 50 A 190 C O from meta-xylylene-diamine 4 Epikote 828 38 B 155 C X (eposy value 188.7) phr: parts per hundred parts of resin.

*2 ...... PGA-X manufactured by Mitsubishi Gas Chemical Company incorporated, N,N,N',N'-tetraglycidyl metha-xylylene-diamine.

*3 ...... Hardening condition A: (80 C, 3 hr) + (15 C, 3 hr) + (180 C, 3 hr).

Hardening condition B: (80 C, 3 hr) + (150 C, 3 Hr) *3 ...... # Not separable at all.

O Separable with difficulty.

X Separable with ease.

@ The word 'EPIKOTE' is a registered trade mark.

TABLE 2

Bending strength of cast sheet (JIS K-6911 which is a Heat Hardening method based on ASTM D-790-71) distortion agents temperature *5 Modulus of of cast sheet Experimental Epoxy Amount Hardening Bending strength elasticity ASTM D-648 Examples resins Kind (phr) condition kgf/mm kgf/mm ( C) 5 Polyglycidyl compound obtained in Example 1 DDM 59.3 C 12.9 465 234 6 " " 29.6 " 13.2 476 246 7 " *4 171 " 11.0 429 234 MNA 8 PGA-X DDM 49.1 " 12.7 398 190 9 " MNA 158 " 10.4 342 186 *4 ...... Methyl nadic anhydride manufactured by Hitachi Chemical Co., Ltd.

*5 ...... Hardening condition C: (80 C, 5 hr) + (150 C, 2 hr) + (180 C, 2 hr).

TABLE 3

Hardening agents Adhesion to polypropyelen film *6 Experimental Amount Hardening Back-side*6 Examples Epoxy resins Kind (phr) conditions Surface *7 (kgf/25 mm) 10 Epikote 828 DDM 26.4 100 C, 3 hr # X (0.1) 11 PGA-X " 49.1 " # # (0.2) 12 Polyglycidyl compound obtained in " 58.7 " # # (at least 2.0) Example 1 13 Epikote 828 *9 43 " # # (0.4) G-740 *6 ...... 180 peeling test in accordance with JIS K-6854 which is a method based on ASTM D-903-49 using RXC-5 having a thickness of 50 manufactured by Tokyo Cellophane Paper Co., Ltd.

*7 ...... The surface was subjected to corona discharge treatment. "#" means that no separation occurred and breakage of material (film) occurred.

*8 ...... The back-side was subjected to no treatment.

# Not separable at all and breakage of material (film) occurred.

# Separable.

X Easily separable.

*9 ...... Goodmide G470 which is a polyamide manufactured by Toto Chemical Co., Ltd.

Experimental Example 14 Two iron plates (100 x 25 x 1.6 mm) surfaces of which were subjected to abrasive treatment and washed with tirchloroethylene were bonded under the pressure of 9 kgf/cm2 using the polyglycidyl compound produced in Example 1 by self-hardening of the compound at 1 400C for 12 hours. Tensile adhesive shear strength thereof was 1 62 kgf/cm2 (JIS--K6850 which is based on ASTM D-1 002-64).

Similarly, two iron plates were bonded using the polyglycidyl compound produced in Example 2.

Tensile adhesive shear strength of thus bonded iron plates was 1 65 kgf/cm2 (JIS--K6850).

Claims (6)

1. A polyglycidyl compound which is represented by the general formula:

wherein

represents

2. A polyglycidyl compound according to claim 1 substantially as described in Example 1 or 2.

3. A method for producing a polyglycidyl compound as claimed in claim 1, which comprises reacting an epihalohydrin with a triamine represented by the general formula:

wherein

is as defined in claim 1, and then treating the reaction product with a base.

4. A process according to claim 3 substantially as described by reference to example 1 or 2.

5. A curable composition comprising, as epoxy resin, a polyglycidyl compound as claimed in claim 1 or 2 and a hardening agent.

6. A hardened product of a polyglycidyl compound as claimed in claim 1 or 2, or of a curable composition as claimed in claim 5.