Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Processes of preparing a desired or intentional composition...
Reexamination Certificate
2000-05-09
2002-04-16
Dawson, Robert (Department: 1712)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Processes of preparing a desired or intentional composition...
C528S094000, C528S116000, C528S117000, C528S118000
Reexamination Certificate
active
06372825
ABSTRACT:
TECHNICAL FIELD
The present invention relates to an aqueous solution of a water-soluble epoxy resin, and a solid thereof, as well as a process for preparing the same.
Epoxy resin was conventionally thought to be insoluble in water. In this sense, an aqueous solution of an epoxy resin of the present invention is entirely novel which reverses the common knowledge in the art.
Epoxy resin is widely used as a sealing material, coating composition, adhesive, etc, in a variety of fields such as electricity, electronics, and civil engineering and construction, because a cured product of epoxy resin has excellent electrical insulating properties, moisture proof, heat resistance, soldering resistance, chemical resistance, durability, adhesive property, and mechanical strength.
BACKGROUND ART
Conventionally, the curing of epoxy resin was carried out by adding a curing agent to epoxy resin, followed by heating. Examples of typical curing agents are diethylenetriamine, triethylenetetramine, isophoronediamine, diaminodiphenylmethane, diaminodiphenylsulfone, polyamides, dicyandiamide, hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methyl nadic anhydride, novolac type phenol resin, tertiary amines, imidazoles, and amine complex of boron trifluoride.
Epoxy resin cured by such a curing agent can be dissolved in an organic solvent, however, no such epoxy resin which can be dissolved in water has been heretofore known.
An object of the present invention is to provide a novel aqueous solution of a water-soluble epoxy resin or a solid thereof which can be dissolved in water, as well as a process for preparing the same.
DISCLOSURE OF THE INVENTION
The present invention provides an aqueous solution of an epoxy resin, which is obtained by the following manner that an epoxy compound or a solution of the epoxy compound in organic solvent, and an amine compound of the formula (1), an aqueous solution thereof, a solution of the amine compound in organic solvent, or a solution thereof in a mixture of water and organic solvent, are mixed together so that the epoxy compound and the amine compound are reacted or polymerized to obtain a solution of an epoxy resin, to which water is added and heated to remove the organic solvent and unreacted amine compound
NH
2
N (R
1
) (R
2
) (1)
wherein R
1
and R
2
are the same or different and each is alkyl having 1 to 6 carbon atoms, alkylene having 2 to 11 carbon atoms or a group represented by —R
3
—N(R
4
)—R
5
— which are formed when both are bonded, R
3
and R
5
are the same or different and each is alkylene having 1 to 6 carbon atoms, and R
4
is alkyl having 1 to 6 carbon atoms or amino group. The invention also provides a solid thereof and a process for preparing the same.
An aqueous solution of an epoxy resin of the invention can be prepared, for example, by the following manner that an epoxy compound or a solution thereof in organic solvent, and an amine compound of the formula (1), an aqueous solution thereof, a solution thereof in organic solvent, or a solution thereof in a mixture of water and organic solvent, are mixed together so that the epoxy compound and the amine compound are reacted or polymerized to obtain a solution of an epoxy resin, to which water is added and heated to distill away the organic solvent, water and unreacted amine compound.
Epoxy compound suitably used in the invention is not specifically limited, and it may be hitherto known one. Examples thereof are glycidyl ether type epoxy resin, glycidyl ester type resin and glycidylamine type epoxy resin.
Examples of glycidyl ether type epoxy resin are bisphenol A type, bisphenol F type, brominated bisphenol A type, hydrogenated bisphenol A type, bisphenol S type, bisphenol AF type, biphenyl type, naphthalene type, fluorene type, phenol novolac type, cresol novolac type, DPP novolac type, trifunctional type, tris(hydroxyphenyl)methane type, and tetraphenylolethane type epoxy resins.
Examples of glycidyl ester type resin are phthalate type and hexahydrophthalate type resins.
Examples of glycidylamine type epoxy resin are tetraglycidyldiaminodiphenylmethane, triglycidyl isocyanurate, hydantoin type, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, aminophenol type, aniline type, and toluidine type epoxy resins.
As an alkyl having 1 to 6 carbon atoms which is represented by R
1
or R
2
of an amine compound of the formula (1) in the invention, there are methyl, ethyl, n-propyl, isopropyl, isobutyl, n-butyl, t-butyl, s-butyl, n-pentyl, isopentyl, t-pentyl, neopentyl, n-hexyl and isohexyl.
As an alkylene having 2 to 11 carbon atoms formed when R
1
and R
2
are bonded, there are ethylene, trimethylene, tetramethylene, pentamethylene, hexamethylene, heptamethylene, octamethylene, nonamethylene, decamethylene and undecamethylene.
As a group represented by —R
3
—N(R
4
)—R
5
— formed when R
1
and R
2
are bonded, there are
—(CH
2
)
2
—N (CH
3
)—(CH
2
)
2
—
—(CH
2
)
2
—N (NH
2
)—(CH
2
)
2
—
Examples of alkylene having 1 to 6 carbon atoms represented by R
3
or R
5
, and examples of alkyl having 1 to 6 carbon atoms represented by R
4
, are the same groups as described above.
In the present invention, the above-mentioned NH
2
NR
1
R
2
type amine compound is suitable to the object of the invention. With amine compounds other than this type of amine compound, it is impossible to obtain a water-soluble epoxy resin.
The above-mentioned amine compound is known, and there are, for example, 1-aminopyrrolidine (NR-1), 1-aminohomopiperidine (AHP), 1,1-dimethylhydrazine (UDMH), and N-amino-N′-methylpiperazine (AMPI).
In preparing the above-mentioned epoxy resin of the invention, an epoxy compound and an amine compound are usually employed in epoxy to amine equivalent ratio of 0.5 to 2.0, preferably about 1 to 1.8.
An aqueous solution of an epoxy resin of the invention can be prepared, for example, by the following manner that an epoxy compound or a solution thereof in organic solvent, and an amine compound of the formula (1), an aqueous solution thereof, a solution thereof in organic solvent, or a solution thereof in a mixture of water and organic solvent, are mixed together so that the epoxy compound and amine compound are reacted or polymerized to obtain a solution of an epoxy resin, to which water is added and heated to distill away the organic solvent and unreacted amine compound.
Examples of organic solvent for dissolving an epoxy compound are solvents which can dissolve epoxy compounds other than ketone, aldehyde, ester and halogen type solvents. Examples thereof are aromatic hydrocarbons such as toluene and xylene, and tetrahydrofuran. Especially, it is preferable to use a mixed solvent of an alcohol and one or more kinds of these solvents. Examples of alcohols are methanol, ethanol and isopropyl alcohol. The alcohol contents of a mixed solvent is about 10 to 95% by volume, preferably about 50 to 90% by volume.
The epoxy compound concentration in an organic solvent can be suitably determined depending on the kind of the solvent, the kind of the epoxy compound, and the concentration of an amine compound to be reacted. It is usually 5 to 100% by weight, preferably about 30 to 80% by weight, in terms of solids content. Too high or too low concentration is undesirable because the former would introduce an irreversible hardening reaction, failing to obtain a water-soluble epoxy resin, and the latter would lower the efficiency of preparation.
An organic solvent for dissolving an amine compound can be selected from the wide variety of compounds capable of dissolving amine compounds, except for ketone organic solvent, aldehyde organic solvent, ester organic solvent and halogen organic solvent. Preferred are alcohols such as methanol and ethanol, and tetrahydrofurans.
As an organic solvent which is used for a mixed solvent of water and an organic solvent in dissolving an amine compound, it is possible to employ the same as the organic solvent that can singly dissolve an amine compound as described above. Especially preferred are alcohols such as methanol and ethanol, because they h
Furuichi Tomohiro
Ishikawa Keiichiro
Kitajima Takashi
Nabeshima Akihiro
Tomotaki Yoshihisa
Arent Fox Kintner & Plotkin & Kahn, PLLC
Aylward D.
Dawson Robert
Otsuka Kagaku Kabushiki Kaisha
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