Compound containing an oxamic acid group, a process for producing the compound, and a resin composition containing the compound

The present invention relates to compounds containing an oxamic acid group, which show high reactivity and have stability for water and are used as paints, adhesives, and plastic materials etc. in the form of a reaction material or a resin. Since into these compounds an oxamic acid group is introduced in a part of the molecule and the oxamic acid group is an ionic functional group, the compounds show superior solubility and dispersing character in water and also, since the oxamic acid group is a group of a disappearing type with heating, the compounds do not remain, after hardening, in the hardened product. Accordingly, the hardened products obtained from these compounds are superior in water-resistant and anticorrosion properties and in durability.

BACKGROUND OF THE INVENTION 
The present invention relates to a compound containing an oxamic acid group 
which has both the properties of high reactivity and high stability for 
water and, in particular, to a compound containing an oxamic acid group 
which is, as a material having a new function, usable as paints, adhesive 
agents, plastic materials, and the like in a form of reaction material or 
resin, in addition, to a process for producing the compound, and to a 
resin composition containing the compound. 
In a case of that coating by a resin in an organic system is carried out in 
a water medium, it is required to lower viscosity of a solution of the 
resin to facilitate coating by a physical method and thus, a technique to 
dissolve or disperse the resin in an organic system becomes important. 
The dissolving and/or dispersing of the resin in an organic system are 
possible by a quality improvement (character change) of the resin with 
introduction of a hydrophilic group and/or an ionic functional group in a 
part of the resin molecule and/or by dispersion of the resin with use of a 
surface active substance having a hydrophilic and/or an ionic functional 
group, but there has been widely used a method where the ionic functional 
group is introduced in a part of the resin. 
This ionic functional group contributes for dispersion and stabilization of 
the resin into water in a stage of that the resin is in a paint condition, 
as described above, and then in a process of coating followed by 
resin-hardening, sometimes displays a function of an acid catalyst for 
hardening and, furthermore, can give a crosslinking structure by reacting 
with a functional group of other hardening agents. However, the functional 
group remaining in a hardened paint film causes lowering in 
water-resisting and anticorrosion properties and in durability of the 
paint film. 
If an example is cited, in an anionic resin for electrodeposition, while an 
ionic functional group such as a carboxyl group shows an anionic character 
and contributes for stabilization of a resin-dispersing solution, it 
contributes for separating resin on a plate by being neutralized on 
turning of an electric current. However, in a stage of a paint film having 
been hardened with heating, the remainder of said carboxyl group etc. 
lowers anticorrosion and water-resisting properties of the paint film. 
Furthermore, a carboxyl group etc. remaining during a hardening time, 
since it has an anionic character, may lower reactivity of the agent in a 
case of that a hardening agent such as an isocyanate etc. is used. 
SUMMARY OF THE INVENTION 
Under these situations, it is at present wanted to get a functional group 
which remains as an ionic group in a paint (a solution) condition, but 
after transforming into a film or a paint film losts the ionic character. 
More desirable is a functional group of the ionic character if it acts as 
an ionic group as itself or by neutralization with an alkali, but loses 
the ionic character by thermal decomposition with heating during a process 
of conversion into a paint film, that is, if it is an ionic group of an 
ion-disappearing type. 
Accordingly, the first object of the present invention is to provide a high 
molecular weight compound which, is stable in water, has a functional 
group being disappeared with heating, shows superiority in such properties 
as affinity and mutual solubility with other organic compounds and resins 
and as solubility for solvents, and may be used as a composition. 
The second object of this invention is to provide a low molecular weight 
compound which has a functional group of ionic character being disappeared 
with heating and is able to favorably use for synthesis of said high 
molecular weight compound. 
The third object of this invention is to provide a composition being 
transformed into a material of hardening character or a paint by using 
said high molecular weight compound as a component. 
The present inventors looked for an ionic functional group disappearing 
with heat, to achieve these objects. 
Hitherto, as a functional group which varies character with heating and 
undergo decarboxylation, for example, is known the following 
ethoxalylamide (refer to Japanese Official Patent Provisional Publication, 
showa 63-45246, and Japanese Official Patent Provisional Publication, 
showa 63-46209), 
EQU --CONHCOCOOR(R=a hydrocarbon group) 
but this functional group shows poor stability for water and is easily 
hydrolyzed, even if a small amount of water is added, transforming it into 
an amide group (--CONH.sub.2), so that it can not be a stable ionic group 
as itself. 
Also, the compounds having an oxamic acid ester group analogous to the 
above have been reported in U.S. Pat. No. 4,846,710 
EQU --NHCOCOOR(R=a hydrocarbon group) 
as a hardening agent for compounds containing an amino group, but this 
functional group itself is not an ionic functional group. 
On the other hand, the following oxamic acid group is 
EQU --NHCOCOOH 
a stable functional group, and it disappears causing decarboxylation with 
heating. 
On a basis of knowledge of this kind, the present inventors attempted to 
introduce an oxamic acid group in a part of a high molecular weight 
compound. Hereinafter, this high molecular weight compound is called a 
resin modified with oxamic acid. Furthermore, the inventors attempted to 
introduce an oxamic acid group into a part of a low molecular weight 
compound in order to get profitably a high molecular weight compound of 
the above kind and, in addition, to invent a production process to get a 
low molecular weight compound of this kind with facility. Hereinafter, the 
low molecular weight compound is called a monomer containing an oxamic 
acid group. 
The monomer containing an oxamic acid group and the oxamic acid group in a 
resin molecule modified with oxamic acid, relating to the present 
invention, show strong acidity of a proton-releasing type in an aqueous 
solution and are a functional group of high stability for water. 
Therefore, the monomer containing an oxamic acid group and the resin 
modified with oxamic acid relating to this invention and containing one or 
more of the oxamic acid group in the molecule are needless to say soluble 
in organic solvents and also dispersion and disolution in water are 
possible with forming salts by an alkali neutralization, although there is 
a case insoluble by themselves. For example, a salt with amines (shown as 
NR.sub.3) is as follows. 
EQU &gt;N--CO--COO.sup.- NHR.sub.3.sup.+ 
Also, as described above, since the oxamic acid group is strongly acidic 
and has an active hydrogen atom in the carboxylic acid moiety, the group 
is nucleophilic in reaction, so that easily reacts with an electrophilic 
functional group with heating and so on. For example, with an epoxy group 
takes place an addition reaction as follows. 
##STR1## 
Furthermore, the oxamic acid group shows high reactivity an active hydrogen 
atom and, for example, undergoes condensation reaction with an amino group 
(H--N.ltoreq.) as follows. 
EQU &gt;NCOCOOH+HN.ltoreq..fwdarw.&gt;NCOCON.ltoreq. 
Like this, the monomer containing an oxamic acid group and the resin 
modified with oxamic acid relating to this invention have both kinds of 
reactivity with an electrophilic compound and/or resin, and an active 
hydrogen-containing compound and/or resin and, therefore, they have 
various kinds of utility as a crosslinking or hardening agent with a use 
of such reactivities. Particularly, an use for resin-hardening is 
mentioned due to high reactivity of the oxamic acid group. 
Besides, since the monomer containing an oxamic acid group relating to the 
invention involves a group of radical polymerization character in the 
molecule and, due to this group, radical polymerization is possible, for 
example, by performing homopolymerization as the need arises or by 
performing copolymerization with other monomers of addition polymerization 
character, converting it into a high molecular weight compound, and 
furthermore, by introducing a resin residue, it is possible to afford an 
ability to form a film. 
The oxamic acid group also has properties of decomposition and 
disappearance. As described below, it converts into a formamide group by 
decarboxylation at low temperature (with heating for 0.5.about. a few 
hours at about 150.degree..about.200.degree. C.), which has been confirmed 
by acid value (AV), IR, and NMR, and also, into a nitril group by 
decarboxylation, decarbonylation, and dehydrogenation at high temperature 
(with heating for a few seconds at 300.degree. C. or higher), which has 
been confirmed by PGC-MS (gas chromatography with thermal decomposition 
and mass spectrum). 
EQU at low temperature:--NHCOCOOH.fwdarw.--NHCHO 
EQU at high temperature:--CH.sub.2 NHCOCOOH.fwdarw.--C.tbd.N 
Accordingly, in a case of that the resin modified with oxamic acid relating 
to the invention is used as a coating material, can be given a paint film 
of a high degree in properties such as water-resistant and 
alkali-resistant properties. Similarly, due to a property of thermal 
decomposition, the monomer containing an oxamic acid group and the resin 
modified with oxamic acid can be used as an acid catalyst not lowering 
water-resistant and anticorrosion properties. 
Hereinafter, the present invention is explained in detail. 
At first, the monomer containing an oxamic acid group is represented by the 
following general formula. 
##STR2## 
[in the formula, A represents a group of radical polymerization character; 
Y represents an alkylene group of carbon number 1.about.8, but the carbon 
atom can be, in part, replaceable with oxygen atom; and R represents a 
hydrogen atom, an alkyl group of carbon atom 1.about.5, or a benzyl group, 
but be able to have a hydroxyl group.] 
Although a group of radical polymerization character A is not especially 
limited, for example, the following groups are cited. 
##STR3## 
[here, R' represents a hydrogen atom or a methyl group.] 
As seen above, in the monomer containing an oxamic acid group in this 
invention the organic group Y combining a group of radical polymerization 
character A with an oxamic acid group should be the one having carbon 
number of more than one. Although there has been reported a compound 
containing an oxamic acid group in a literature, Makromolekular Chemie 
1970, 131, pp. 247.about.257, 
##STR4## 
this compound has not the above-mentioned organic group Y and solubility 
for organic solvents is very poor. 
Although said monomer containing an oxamic acid is useful for other 
purposes besides the use for synthesis of the resin modified with oxamic 
acid in this invention, if the molecular weight of monomers containing an 
oxamic acid group is too small or too large, in a case of that the 
monomers containing an oxamic acid group are mixed with an optional 
composition as an acid catalyst or a hardening agent, the mutual 
solubility and affinity with other organic compounds and resins become 
poor and the stability and dispersing character in the composition also 
become poor and, as a result, various kinds of addition effects expectable 
as an acid catalyst and as a hardening agent for the oxamic acid group are 
not displayed. Not only this problem, but also other problems are affraid 
in a practical use. 
Although the synthetic method for the monomers containing said oxamic acid 
group is not especially limited, one example is to use that a reaction 
between an amino group and an oxalic acid ester gives an oxamic acid ester 
which is hydrolyzed yielding an oxamic acid group and, in this case, a 
synthesis is treatment of an amino compound having a group of radical 
polymerization character with an equivalent mole or an excess of an oxalic 
acid ester such dimethyl oxalate and diethyl oxalate followed by 
hydrolysis of the produced ester. 
Here, as the amino compounds having a group of radical polymerization 
character are exemplified, for example, polymerizable amines such as 
N-(6-aminohexyl)methacrylamide etc., but there is no limitation with this 
compound. 
The conditions for the reaction between said amino compound and an oxalic 
acid ester are not especially limited, but proper setting is preferred 
depending upon the kind of starting material etc. For example, an amino 
compound diluted with an optional solvent is added dropwise maintaining 
reaction temperature at 20.degree..about.30.degree. C. during 1.5.about.3 
hours into a definite amount of diethyl oxalate and then, further stirring 
of the obtained mixture is recommended to proceed the reaction. In this 
case, if the reaction temperature is too high or the reaction progress is 
too fast, it is afraid that two moles of the amine react with one mole of 
diethyl oxalate, so a high molecular weight compound may be produced. 
Besides, as a diluting agent are cited a low class of alcohols such as 
ethanol and isopropanol etc., aromatic hydrocarbons such as benzene and 
xylene etc., aliphatic hydrocarbons such as hexane and pentane etc., and 
ethers such as diethyl ether and tetrahydrofuran etc. 
Hydrolysis of the obtained oxamic acid esters, for example, can be carried 
out at 20.degree..about.30.degree. C. with adding a necessary amount of 
water and by using an amine (triethylamine etc.) as a catalyst. In this 
case also, if the reaction temperature is too high, an amine isolated with 
hydrolysis reacts with another oxamic acid ester or an oxamic acid salt 
and, for example, forms a bond &gt;NCO--CON&lt;, which may lead to a high 
molecular weight compound. 
Alcohols forming during reaction and excess amines may be removed by 
heating under reduced pressure etc. also, when hydrolysis is carried out 
with addition of a large amount of water, the aimed monomer containing an 
oxamic acid group is obtained in a form being dissolved and dispersed in 
water as an ammonium salt, but if neutralized by an acid, it can be taken 
as crystals insoluble in water. It was confirmed by NMR and IR that the 
hydrolysis from the oxamic acid ester into the forementioned oxamic acid 
has taken place in the C--O bond, and its reaction yield in percentage is 
80% or more. 
The below-described 1 shows an example for the forementioned synthesis, in 
which at first methacrylamide is obtained and this amide treated with an 
oxalic acid ester leading to an ester compound that is hydrolyzed. 
However, the synthesis of a monomer containing an oxamic acid group is not 
limited with this example and also, the below-described methods such as 
such as 2.about.4 can be applied. 
##STR5## 
[in the formulas, X represents hydrogen, halogen, or a monovalent 
hydrocarbon group substituted with a functional group or unsubstituted, 
etc.; R represents a hydrocarbon group substituted with a functional group 
or unsubstituted, etc.] 
Hereinafter, novel examples of the monomers containing an oxamic acid group 
relating to this invention are explained. That is, in said monomers 
containing an oxamic acid group, is explained a monomer containing an 
oxamic acid group, in which at least one 1-substituted 
(unsubstituted)-2-hydroxyethyl group is combined with a nitrogen atom of 
at least one oxamic acid group. Since the monomer 
##STR6## 
[X represents hydrogen, halogen, a hydrocarbon substituted with a 
functional group or unsubstituted, and an optional functional group etc.] 
containing an oxamic acid group has a hydroxyl group besides the oxamic 
acid group, the reactivity is better and, as a result, for example, a 
paint film of improved crosslinking density and stronger hardness can be 
obtained. 
Said monomers containing an oxamic acid group can be prepared by adding a 
necessary amount of water to a morpholine-2,3-dione group substituted with 
a proper organic group having the below-described ethylenic unsaturated 
bond: 
##STR7## 
and then, by performing hydrolysis under presence of an amino compound to 
open the morpholine group. 
Here, said morpholinedione can be prepared, for example, from a reaction of 
the below-described N-hydroxyethylmorpholinedione: 
##STR8## 
with a compound having a polymerizable unsaturated bond. Besides, the 
morpholinedione is obtained from a reaction of diethyl oxalate with 
diethanolamine. Although the compound having a polymerizable unsaturated 
bond is not especially limited, are cited, for example, acryloyl chloride, 
methacryloyl chloride, isocyanatoethyl methacrylate, methacryloyl 
isocyanate, methyl methacrylate, ethyl methacrylate, ethyl acrylate, butyl 
acrylate, m-isopropenyl-.alpha., .alpha.-dimethylbenzyl isocyanate. 
Hydrolysis of the obtained morpholinedione substituted with an organic 
group and ring cleavage of the morpholinedione can be carried out in the 
same way as for hydrolysis of said oxamic acid ester. By the way, 
regarding the ring cleavage reaction of substituted morpholinediones, 
there has been reported in U.S. Pat. No. 4,118,422 a synthesis of polyols 
by a reaction of said morpholine with polyoxypropylamine having a primary 
amine. 
Resins modified with oxamic acid are explained. These are compounds 
containing an oxamic acid group shown by the below general formula (II). 
##STR9## 
[in the formula (II), P represents a polymer residue having a molecular 
weight of 1000 or more, R represents a hydrogen atom, an alkyl group of 
carbon atom 1.about.5, or a benzyl group, and n represents a positive 
integral number. But R may have a hydroxyl group as a substituent.] 
That is, the resins modified with oxamic acid are those chemically modified 
with an oxamic acid group by introducing one or more of an oxamic acid 
group into an optional position in a main or a side chain of resins such 
as acryl resin, polyester resin, polyamide resin, epoxy resin, amino 
resin, polyethylenimine resin, hydrocarbon resin, silicone resin, 
fluororesin, and their modified resins etc., and the bonding position and 
the bonding number are not limited. Concretely, the introducing position 
and number of the oxamic acid group can be optionally combined each other, 
for example, at an end position of the main chain and both ends, a 
specified position in a midway of the main chain or an unspecified 
position, an end position of the side chain, and a specified position in a 
midway of the side chain or an unspecified position. 
For said acryl resin are cited, as good examples, the copolymers between an 
optional polymerizable monomers and a monomer in an acryl series 
containing a hydroxy group or a monomer in acryl series containing an 
epoxy group. As the former polymerizable monomers are cited optional 
acrylic acid esters such as methyl acrylate, ethyl acrylate, and n-butyl 
acrylate etc.; methacryl acid esters such as methyl methacrylate, ethyl 
methacrylate, and n-butyl methacrylate etc.; acid or amide monomers in an 
acryl series such as acrylic, methacrylic, and itaconic acids, and 
acrylamide and diacetoneacrylamide etc.; optional monomers such as styrene 
and vinylstyrene etc. As the latter monomers in a hydroxyl 
group-containing acryl series are cited 2-hydroxyethyl acrylate and 
2-hydroxyethyl methacrylate etc., and as the monomers in an epoxy 
group-containing acryl series are cited glycidyl methacrylate etc. The 
hydroxy and epoxy groups etc. in said resins can be used for introduction 
of an oxamic acid group. It is proper that the hydroxy group values of 
these resins are in a range of 5.about.100, and the acid values in a range 
of 2.about.150, and the molecular weight in a range of 
1,000.about.1,000,000, but the values are not limited within the ranges. 
As said polyester resins can be used the resins obtained from thermal 
polymerization condensation of polyvalents carboxyl acids represented by, 
for example, 2-valent carboxyl acids such as phthalic anhydride, 
isophthalic acid, terephthalic acid, succinic anhydride, adipic acid, 
azelaic acid, hexahydrophthalic anhydride, maleic anhydride, and fumaric 
acid etc., or 3-valent or 4-valent carboxyl acids such as trimellitic 
anhydride and pyromellitic anhydride etc. with polyalcohols such as 
ethyleneglycohol, propyleneglycohol, 1,6-hexanediol, diethyleneglycohol, 
triethyleneglycohol, glycerol, trimethylolpropane, pentaerythritol, and 
dipentaerythrite etc. The hydroxyl and carboxyl groups can be used for 
introduction of an oxamic acid group. Besides, favorable is that these 
have a hydroxyl value in a range of 5.about.150, an acid value in a range 
of 5.about.150, and a molecular weight in a range of 1,000.about.100,000, 
but that is not specially limited within the values. 
As examples for polyamide resins are given compounds represented by the 
following formula: 
##STR10## 
[in the formula, R.sup.1 and R.sup.2 independently represent an alkylene, 
alkenylene, alkynylene, cycloalkylene, or arylene group of 1.about.20 
carbon atoms substituted with a functional group or unsubstituted, and n 
is positive integral number of 2 or more.] As a commercially available 
product is favored `Normex` produced from DuPONT Co. The amino group in 
the resins can be used for introduction of an oxamic acid group. Also, the 
molecular weight is preferred to be in a range of 200.about.100,000, but 
there is no problem even if it is deviated from the range. 
As epoxy resins are favored the resins containing an epoxy group in a main 
and/or side chains and having epoxy equivalents of 180.about.10,000. For 
examples, are cited an epoxy resin of an epibis type, an epoxy resin of a 
novolac type, an epoxy resin of a resorcinol type, an epoxy resin of a 
polyglycohol type (a glycohol ether type), and an epoxy resin of a cyclic 
oxirane type, all of which can be obtained from bisphenol A and 
epichlorohydrin. Introduction of an oxamic acid group is carried out by 
being derived from the epoxy group in these resins. 
As amino resins are favorably used the etherized amino resin etc. which are 
obtained with addition condensation of melamine, guanamine, urea, and 
these derivatives etc. with formaldehyde followed by modification with 
alcohol. More concretely, are cited, as good examples, methylated melamine 
resin, butylated melamine resin, methylated and butylated melamine resins, 
and benzoguanamine resin etc. As commercially available products are 
preferred a melamine resin J-820-60 (molecular weight of 1240 averaged by 
number) made by Dainippon Inki Kagaku Kogyo Co., a melamine resin J-830-60 
(molecular weight of 1120 averaged by number) made by the same company and 
a guanamine resin BL-60 (acid value of 0.5 or less) and BX-3900 (acid 
value of 0.5 or less), both of which are made by Sanwa Chemical Co. The 
imino and methylol groups in these resins can be used for introduction of 
an oxamic group. Also, the molecular weight is not especially limited, but 
a preferred range is in 200.about.100,000. 
As polyethyleneimine resins are, for example, the compounds shown by the 
following general formula, 
##STR11## 
[in the formula, R= 
##STR12## 
a=1.about.100, and b=1.about.100] and so on can be used and, furthermore, 
compounds are preferred, for which the amine values of a primary amine and 
a secondary amine are 5 or more and the molecular weight is in a range of 
600.about.100,000. As commercially available products are exemplified 
Epomine SP-103 (molecular weight of 250), Epomine SP-200 (molecular weight 
of 10,000), Epomine P-1000 (molecular weight of 70,000), and .left 
brkt-top.Epomine SP-018 (molecular weight of 1,800), all of which were 
made from Nippon Shokubai Kagaku Kogyo Co. 
As silicone resins are favorable used the silicone resins, as shown with 
the following formula, having an amino group at both (or one) end 
positions: 
##STR13## 
[in the formula, R and R' independently represent an alkylene, alkenylene, 
alkynylene, cycloalkylene, or arylene group substituted by a functional 
group of carbon number 1.about.20 or unsubstituted, and X.sup.1 
.about.X.sup.4 independently represent hydrogen, or an aryloxy, an alkoxy 
group of carbon number 1.about.20, or an aryl, or an ester bond or an 
urethane bond, or an alkyl group of carbon number 1.about.400 which is 
able to involve a carboxylic acid group, and n represents a positive 
integral number of 2 or more. Here, the end amino group can be used for 
introduction of an oxamic acid group. The molecular weight is preferred to 
be in a range of 200.about.500,000. 
As hydrocarbon resins are exemplified the resins in a butadiene series. As 
the butadiene resins are preferable for use the polybutadienes of a 1,4 
type or 1,2 type (the contents of each structure are optional), and it is 
recommended that at least an end functional group is a hydroxyl, an epoxy, 
an amino, and an isocyanate (--NCO) group etc. As commercially available 
products can be used, for example, a polybutadiene having a hydroxyl group 
at an end position R-45 EPI and a polybutadiene having a NCO group at the 
end position HTP-5MLD, both of which are made from Idemitsu Sekiyu Kagaku 
Co. Also, the molecular weight is preferred to be in a range of 
150.about.50,000, but it is not limited in the range. 
As fluororesins are favorably used the copolymer etc. of fluorinated 
modified resins such as a fluorinated acrylic acid esters and fluorinated 
methacrylic acid esters (for examples, 2,2,2-trifluoroethyl acrylate, 
1,1,1,3,3,3-hexafluoroisopropyl acrylate, and 2,2,2-trifluoroethyl 
methacrylate etc.) or fluorinated styrene (for an example, 
2,3,4,5,6-pentafluorostyrene etc.) with an acrylic acid or an methacrylic 
acid ester monomer containing a hydroxyl or an epoxy group. The hydroxyl 
or epoxy group can be used for introduction of an oxamic acid group. Also, 
the ratio of said fluorinated modified monomer against other monomers in 
an acryl series is 1.about.99/99.about.1 and the molecular weight is 
preferred to be in a range of 500.about.1,000,000. 
The acid value of these oxamic acid-modified resins is wanted to be 2 or 
more from a point of affinity for water. More concretely, it is preferred 
that the acid value is about 5.about.500 and most preferred to be about 
5.about.150. As the acid value increases, the solubility for water or 
dispersion ability in water increase, so that it becomes possible to use 
those as water-soluble coating resin or coating resin for 
electrodeposition. 
Using the resin residue having a functional group (--OH, --COOH, and 
--NH.sub.2 etc.) to introduce an oxamic acid group as mentioned above, a 
resin modified with oxamic acid can be synthesized by introducing an 
oxamic acid group as described below. 
At first, if the functional group to introduce an oxamic acid group is an 
amino group, the modification can be carried out by that the functional 
group itself is allowed to react with an oxalic acid ester and then, the 
oxamic acid ester part is hydrolyzed. If said functional group is a 
hydroxyl group or a carboxyl group, the oxamic acid group can be 
introduced by that a compound half-blocked by a monooxalic acid ester, 
which is obtained by treating a reaction product between hydroxylamine and 
diethyloxalic acid with diisocyanate, is subjected to react with said 
functional group in the resin. For example, for a hydroxyl group in an 
optional resin, the reaction is shown as follows. 
##STR14## 
[in the formulas, R.sup.1 and R.sup.2 independently represent an alkylene 
group of carbon number 1 to 20, an alkenylene, an alkynylene, a 
cycloalkylene, or an arylene group.] 
Furthermore, for a glycidyl group in a resin an amination carried out by 
using a ketimine etc. and then, an oxamic acid group can be introduced. 
Hereinafter, taking an epoxyresin (Ep) as an example, one example for the 
synthetic process is shown with chemical reaction formulas (only an end 
position or a part of the resin is in detail shown here). 
##STR15## 
[in the formulas, X is the same as above, and R.sup.1, R.sup.2, and 
R.sup.3 independently represent a hydrocarbon group etc. substituted with 
a functional group or unsubstituted.] 
Also, if said amino-modified epoxy resin A is treated with an equivalent 
mole of diethyl oxalate, is obtained an epoxy resin modified with oxamic 
acid having a repeating unit, as shown below, on the way of the chain. 
##STR16## 
[in the formula, R.sup.1, X and n are the same as above.] 
Besides, the synthetic method for the resin modified with oxamic acid in 
this invention is not limited by the introduction of an oxamic acid group 
into the resin residue as mentioned above, and for example, a method is 
also adapted that in a monomer stage an introduction of the oxamic acid 
group is carried out to synthesize said oxamic acid monomer and then, this 
monomer alone or together with other polymerizable monomers (vinylic 
compound etc.) is polymerized. Concretely, in a case of an acryl resin 
modified with oxamic acid, are at first synthesized an acrylic acid or a 
methacrylic acid derivative (an oxamic acid monomer), and one kind or more 
of the derivatives is polymerized or copolymerized with a monomer in an 
acrylic acid series or methacrylic acid series not containing an oxamic 
acid group, leading to a synthesis of an acryl resin modified with oxamic 
acid. Also, a modified resin can be gotten by copolymerizing the oxamic 
acid monomer with a polymerizable monomer (butadiene and styrene etc.) 
other than the monomer in the acrylic acid series. 
Furthermore, said resins modified with oxamic acid relating to this 
invention, like said novel monomer containing an oxamic acid monomer, may 
be the compounds containing at least one oxamic acid group combined with 
an 1-substituted or unsubstituted 2-hydroxyethyl group at the nitrogen 
atom. Since the resins modified with oxamic acid of this type have a 
hydroxyl group besides the oxamic acid group, can make a paint film of 
strong hardness. 
Said resins modified with oxamic acid having an oxamic acid group 
substituted with a hydroxylethyl group can be synthesized by a method 
similar to that used for the monomer containing an oxamic acid group, that 
is, hydrolysis of a substituted morpholinedione containing 
intramolecularly a resin residue followed by ring cleavage of the 
morpholine-2,3-dione. Besides, said morpholinedione substituted with a 
resin residue can be obtained by chemical modification of the resin 
resulting from said morpholinedione substituted with an organic group and, 
for this, an optional reactive functional group, if necessary, is 
previously introduced into the morpholinedione substituted with an organic 
group and/or the resin. 
For the forementioned monomers containing an oxamic acid group and the 
resins modified with oxamic acid, although various use can be considered 
with no special limitation, the below-described use can be considered by 
using several kinds of properties being involved in the oxamic acid group. 
At first, since the oxamic acid has nucleophilic reactivity, it can be used 
as a hardening agent for a resin of electrophilic character and, on the 
other hand, from a point of high reactivity of the oxamic acid group with 
an active hydrogen, can be used as a hardening agent for a resin having an 
active hydrogen as represented by melamine resin etc. For use of those 
kinds, among said monomers containing an oxamic acid group and the resins 
modified with oxamic acid, the compounds containing intramolecularly two 
or more of the oxamic acid group are suitable and, a resin composition of 
a hardening type can be prepared by distributing for the above monomers or 
resins a proper hardening resin and, if necessary, an addition agent such 
as a diluting solvent, a filling agent, and a coloring agent etc. A paint 
film of strong hardness can be obtained by applying the composition for a 
surface of proper board material followed by hardening with heating. 
Since any resin modified with an oxamic acid easily reacts with an active 
hydrogen, it can be used as a hardening resin at low temperature, where an 
active hydrogen-containing compound such as a kind of amine or a melamine 
resin is used as a hardening agent, and so it can be put to practical use 
as a resin for coating or a resin for paint. For example, by adding an 
organic solvent and/or water to a resin modified with oxamic acid in this 
invention and, if necessary, by adding a basic compound such as an amino 
compound or a compound capable of a reaction of a mutual type 
(crosslinking) and, if further necessary, by adding an optional additive 
for paint such as an organic or an inorganic sealing agent, a coloring 
agent (an organic, an inorganic, or a metal pigment or dye etc.), a 
viscosity-lowering agent, a leveling agent, an antifoaming agent, and a 
surface-adjusting agent etc., a resin composition for paint is prepared, 
from which a film of high hardness can be obtained in a similar way as 
described above. Besides, in that case a composition ratio between the 
resin modified with oxamic acid (x) and a compound capable of mutually 
reacting with x, is not especially limited, but 
EQU x/y=30.about.100/70.about.0 
the ratio shown by this equation is preferred. 
A compound capable of mutually reacting with the resin modified with oxamic 
acid is, for example, what at least a group chosen from a hydroxyl, an 
amino, and an epoxy groups is involved in the molecule. Since the oxamic 
acid group has a property of facile decomposition and disappearance with 
heating, the resin modified with oxamic acid can be used as a 
water-resistant and alkali-resisting, water-soluble resin for paint. 
Furthermore, from a point of a superior water-dispersing and water-soluble 
character (for example, an amine salt of oxamic acid etc.), the resin 
modified with oxamic acid in this invention is very useful as a resin for 
water paint and electrodeposition paint. 
Similarly, the resins modified with oxamic acid in this invention having 
superior dispersing and soluble characters in water can be used as a 
surface-active agent for an optional resin. For example, by combining the 
resin modified with oxamic acid with at least one or more kinds of an 
oxamic acid derivative combined with an organic acid chosen from acrylic 
resin, polyester resin, polyamide resin, epoxy resin, amino resin, 
polyethyleneimine resin, silicone resin, resin in a butadiene series, 
fluororesin, and their modified resin, is prepared a resin composition of 
high dispersing character. 
Moreover, since the oxamic acid group shows a strong acidity by releasing a 
proton in a water, for example, the monomers containing an oxamic acid 
group and the resins modified with oxamic acid can be used as an acid 
catalyst for hardening of an appropriate resin. In this case, since the 
oxamic acid group disappears after hardening, for example, there needs not 
to worry about a remainder in a hardened paint film which causes lowering 
film capacity. 
The forementioned are representative examples for use, and the use of the 
monomers containing an oxamic acid group and the resins modified with 
oxamic acid is not limited within the forementioned and, for example, 
needless to say, an use as an electrification-protecting agent is 
possible. Also, although an explanation was previously given for the 
hardening resin composition, which contains a resin having an active 
hydrogen or a resin of electrophilic character and contains a monomer 
having an oxamic acid group or a resin modified with oxamic acid in this 
invention having two or more oxamic acid groups in the molecule, the 
reactivity of the oxamic acid group with an active hydrogen or an 
electrophilic functional group does not limit combination of the above 
both. That is, it is not necessary that one hand is a monomer containing 
an oxamic acid group and the other hand is a resin and, for example, a 
paint film of strong hardness can be made by that an active 
hydrogen-containing compound, which is represented by a polyamine 
(diethylenetriamine), is allowed to react with a monomer containing an 
oxamic acid group in this invention having two or more oxamic acid groups 
in the molecule. For a reaction with an electrophilic compound containing 
intramolecularly an epoxy group etc. is the same. 
Next, with respect to an identification method for oxamic acid derivatives 
in this invention, there are cited a structure analysis by instruments 
such as IR, NMR, and GC-MS; molecular weight measurements by GPC (gel 
permeation chromatography) and physical properties measurements such as, 
for example, solubility, SP value, viscosity, hydroxyl group value, and 
acid value etc.; and formation and disappearance of the oxamic acid group 
and identification of a resin residue and other functional groups can be 
carried out by performing qualitative and quantitative analysis in 
combination with the above. 
Hereinafter, as a example, identification results of epoxy resin modified 
with oxamic acid by using .sup.13 C-NMR and IR are described. This 
modified resin was obtained by introducing an oxamic acid group into an 
epoxy resin material; the commercial name of YD-011 (YD-011, a 
commercially available epoxy resin of an epi-bis type having epoxy 
equivalents of 450 made by Touto Kasei Co.) as the below and had a 
structure form of triethylammonium salt derivative. 
In a flask equipped with a stirrer, a thermometer, a nitrogen-inlet tube, 
and a reflux condenser were placed 90 g of an epoxy resin material, and 
then, added 60 g of methyl isobutyl ketone to get a solution, which was 
warmed up to 120.degree. C. under nitrogen atmosphere and to which was 
added 52 g of a ketimine material obtained from a reaction of 
diethylenetriamine with methyl isobutyl ketone. The mixture was subjected 
to a reaction at 120.degree. C. for 1.5 hours and, after the reaction 
finished, cooled to 25.degree. C., and hydrolysis of the ketimine was 
carried out with addition of 5.8 g of water to obtain an epoxy resin 
modified by an amine. Next, the reaction solution containing an 
amine-modified epoxy resin obtained as the above was added dropwise during 
1.5 hours maintaining the reaction temperature at 30.degree. C. to 58 g 
(0.4 moles) of diethyloxalate placed in a flask equipped with a stirrer, a 
thermometer, a dropping funnel, and a reflux condenser flask. After the 
dropping finished, stirring was further continued for 1 hour at 25.degree. 
C. and then, crystals separated were taken by filtration. Then, the 
thus-obtained reaction product and 300 ml of water were placed in a flask 
and a hydrolysis reaction was carried out by adding dropwise 23 g of 
triethylamine (0.22 moles) during 30 minutes to obtain triethylammonium 
salt of an epoxy resin modified with an oxamic acid. 
Assignments of major chemical shifts, .delta.(ppm) in .sup.13 C-NMR, are 
166.2 and 163.3 for C.dbd.O in an oxamic acid group; 158.3, 142. 7, 127.4, 
and 113.9 for a benzene ring in bisphenol A; 59.0 for CH.sub.2 O--, 
&gt;CH--OH, 41.1 for --CH.sub.2 NH--; 30.8 for &gt;C&lt; in bisphenol A; and --14.1 
for --CH.sub.3 in bisphenol A. 
Assignments of major IR absorption spectra (wave number, cm.sup.-1) are 
3400 for O--H stretching vibration in --COOH; 1660 for C.dbd.O stretching 
vibration in --COOH; 1630 for C.dbd.O stretching vibration in --NHCO--; 
1600, 1510, and 1460 for C.dbd.C stretching vibration of a benzene ring in 
bisphenol A; and 1580 for --NH-- deformation vibration. 
Furthermore, hereinafter is shown identification results for the 
below-described ethylenedioxamic acid, HOCOCONHCH.sub.2 CH.sub.2 NHCOCOOH 
, by means of .sup.13 C-NMR and IR. 
Assignments of major chemical shifts, .delta.(ppm) in .sup.13 C-NMR, are 
162.0 and 159.6 for C.dbd.O in an oxamic acid group and 38.5 for 
--CH.sub.2 --. 
Assignments of major IR absorption spectra (wave number, cm.sup.-1) are 
3200 for O--H stretching vibration in --COOH; 1760 for C.dbd.O stretching 
vibration in --COOH; 1680 for C.dbd.O stretching vibration in --NHCO--; 
and 1560 for --NH-- deformation vibration. 
Since the monomers containing an oxamic acid group and the resins modified 
with oxamic acid relating to this invention involve an oxamic acid group 
in the molecule, they show very high stability for water and strong 
acidity and can be dissolved or dispersed in water by forming a salt with 
an amine etc. The oxamic acid group responsible for this speciality easily 
disappears by heating and converts into a functional group of non-ionic 
character. 
Also, said monomers containing an oxamic acid group and the resins modified 
with an oxamic acid have high reactivity for an active hydrogen and a 
functional group of electrophilic character and, in addition, if 
necessary, can contain a resin residue or a functional group which is able 
to lead to a high molecular weight compound. 
Furthermore, said monomers containing an oxamic acid group and the resins 
modified with oxamic acid show a superior affinity with other compounds 
and resins, so that they can make various kinds of composition having 
superior dispersing property. Therefore, by using the monomers containing 
an oxamic acid group and the resins modified with an oxamic acid as a 
hardening agent or an acid catalyser for an active hydrogen-containing 
resin or a resin of electrophilic character, and by using the the resins 
modified with oxamic acid as a hardening resin for various kinds of 
paints, they can make, for example, a paint film of a high anticorrosion 
property etc, where the oxamic acid group has disappeared after hardening.

DESCRIPTION OF THE INVENTION 
Concrete examples of this invention are hereafter explained in combination 
with comparison examples in the following order. 
1 synthesis of the monomers containing an oxamic acid group 
2 polymerization of the monomers containing an oxamic acid group 
3 synthesis of the compounds containing an oxamic acid group and 
transformed into high molecular weight compounds 
4 synthesis of the resins modified with oxamic acid 
5 compositions containing an oxamic acid group-containing compound 
1 Synthesis of the monomers containing an oxamic acid group 
EXAMPLE 1 
To 730.7 g (5 moles) of diethyl oxalate was added dropwise at room 
temperature a solution of 61.1 g (1 mole) of ethanolamine in 500 ml of 
acetone and, after the addition finished, treatment of the mixture by 
distillation under reduced pressure to remove the formed ethanol and the 
acetone and an excess amount of diethyl oxalate yielded ethyl 
2-hydroxyethyloxamate. A mixture of 80.5 g (0.5 moles) of this ethyl 
2-hydroxyethyloxamate, 50.6 g (0.5 moles) of triethylamine (hereinafter, 
referred to as TEA), 20.0 g of water, and 1000 ml of dioxane was warmed 
under reflux for 8 hours and treated with solvent removal followed by 
dehydration yielded a triethylamine salt of 2-hydroxyethyloxamic acid. A 
mixture of 11.7 g (0.05 moles) of this triethylamine salt of 
2-hydroxyethyloxamic acid and 5.1 g (0.05 moles) of TEA was treated with 
dehydration by molecular sieve and then, dissolved with warming into 300 
ml of THF. To this THF solution was added dropwise under a refluxing 
condition during 0.5 hours a solution of 5.2 g (0.05 moles) of methacrylic 
acid chloride in 30 ml of THF and, after the addition finished, the 
mixture was further stirred under the condition for 6 hours and treated 
with fractional extraction to get methacryloyloxyet hyloxamic acid of the 
following structure: 
##STR17## 
Besides, identification of the methacrylolyloxyethyloxamic acid 1 was 
carried out with .sup.13 C-NMR spectra analysis (ppm, in CDCL.sub.3) and 
the results were 17.93 for (2), 38.86 for (6); 62.35 for (5), 120.59 for 
(1), 138.86 for (3), 158.01 for (7), 160.56 for (8), and 167.06 for (4). 
EXAMPLE 2 
In example 1, when the reaction of a triethylamine salt of 
2-hydroxyethyloxamic acid with methacrylic acid chloride was performed, 
5.5 g (0.05 moles) of methacryloylisocyanate were used instead of 
methacrylic acid chloride with no use of TEA and the reaction was carried 
out at room temperature. Except the forementioned, the same procedure as 
for example 1 was carried out to get methacryloylcarbamoyloxyethyloxamic 
acid of the following structure. 
##STR18## 
In example 1, when the reaction of a triethylamine salt of 
2-hydroxyethyloxamic acid with methacrylic acid chloride was performed, 
7.8 g (0.05 moles) of isocyanatethyl methacrylate were used instead of 
methacrylic acid chloride, TEA was not used, and 0.01 g of di-n-butyltin 
dilaurate (hereinafter, referred to as DBTL) was used as a reaction 
catalyst. Except the forementioned, the same procedure as for example 1 
was carried out to get methacryloyloxyethyl carbamoyloxyethyloxamic acid. 
##STR19## 
EXAMPLE 4 
In example 3, except that 10.1 g (0.05 moles) of m-isopropenyl-.alpha., 
.alpha.-dimethylbenzylisocyanate was used instead of isocyanatethyl 
methacrylate, the same procedure as for example 3 was carried out to get 
[N'-(m-isopropenyl-.alpha., .alpha.-dimethylbenzyl) carbamoyloxyethyl] 
oxamic acid of the following structure. 
##STR20## 
EXAMPLE 5 
In example 1, except that 105.1 g (1.0 mole) of 2-(2-aminoethoxy)ethanol 
was used instead of ethanolamine, the same procedure as for example 1 was 
carried out to get methacryloyloxyethyl oxyethyloxamic acid of the 
following structure. 
##STR21## 
EXAMPLE 6 
In example 2, except that 105.1 g (1.0 mole) of 2-(2-aminoethoxy)ethanol 
was used instead of ethanolamine, the same procedure as for example 2 was 
carried out to get methacryloylcarbamoy loxyethyloxyehyloxamic acid of the 
following structure. 
##STR22## 
EXAMPLE 7 
In example 3, except that 105.1 g (1 mole) of 2-(2-aminoethoxy)ethanol was 
used instead of ethanolamine, the same procedure as for example 3 was 
carried out to get methacryloyloxyethyl carbamoyloxyethyloxyethyloxamic 
acid of the following structure. 
##STR23## 
EXAMPLE 8 
In example 4, except that 105.1 g (1.0 mole) of 2-(2-aminoethoxy)ethanol 
was used instead of ethanolamine, the same procedure as for example 4 was 
carried out to get [N'-(m-isopropenyl-.alpha., 
.alpha.-dimethylbenzyl)carbamoyloxyethyloxyethyl] oxamic acid of the 
following structure. 
##STR24## 
EXAMPLE 9 
In a flask equipped with a stirrer, a thermometer, a dropping funnel, and a 
reflux condenser were placed 43 g (0.5 moles) of metacrylic acid and 300 
ml of dichloromethane and to this mixture cooled with ice was added 103.5 
g (0.5 moles) of dicyclohexylcarbodiimide during 15 minutes. After 
stirring for another 15 minutes, this mixture was added dropwise during 1 
hour into a dichloroethane solution of 58 g of 1,6-hexamethylenediamine 
(0.5 moles, 50% by weight), and the reaction mixture obtained was warmed 
to 25.degree. C. with stirring, filtrated to remove floating solid, and 
added into 300 ml of chilled water. Separation of an organic layer 
followed by distillation under reduced pressure to remove solvent yielded 
crystalline N-(6-aminohexyl)methacrylamide. A solution prepared by 
dissolving the crystals into 100 ml of ethanol was added dropwise during 2 
hours maintaining the reaction temperature at 30.degree. C. into 292 g (2 
moles) of diethyl oxalate. After the addition finished, the stirring was 
continued at 25.degree. C. for further 1 hour and then crystals separated 
were taken by filtration. The obtained crystals and 150 ml of water were 
placed in a flask, and hydrolysis was carried out with addition of 51 g 
(0.5 mole) of TEA into the aqueous solution during 30 minutes. To the 
resulting aqueous solution 41 ml of concentrated hydrochloric acid was 
added and then crystals separated was taken by filtration to obtain 
6-methacryloylaminohexyloxamic acid 9. 
##STR25## 
Identification was carried out with IR, which showed absorptions for 
carboxylic acid at 1760 cm.sup.-1, for carbonyl at 1680 cm.sup.-1 and for 
amide at 1560 cm.sup.-1. The acid value and molecular weight were, 
respectively, 215 (calcd. 223) and 252. 
EXAMPLE 10 
In a flask similar to that used for example 9 was placed 146 g (1.0 mole) 
of diethyl oxalate, and to this flask was added dropwise 26 g (0.25 moles) 
of diethanolamine maintaining reaction temperature at 30.degree. C. during 
1 hour. After the dropping finished, the stirring was continued at 
25.degree. C. for further 2 hours and then crystals separated were taken 
by filtration to obtain N-hydroxyethylmorpholine-2,3-dione. 
Next, in a flask equipped with a stirrer, a thermometer, a decanter, a 
nitrogen gas-inlet tube, and a reflux condenser were placed 50 g (0.58 
moles) of methacrylic acid, 0.1 g (0.1% by weight) of hydroquinone, and 
200 ml of methyl isobutyl ketone (hereinafter, referred to as MIBK) and to 
this mixture was added 54 g (0.58 moles) of 
N-hydroxyethylmorpholine-2,3-dione, which was prepared in a way as above. 
Then, the mixture was warmed at 120.degree. C. and the reaction continued 
for 2 hours by removing water being formed during the reaction by the 
decanter by means of azeotropic distillation. Return of the solution 
temperature to room temperature followed by removal of MIBK under reduced 
pressure gave 2-(1-morpholyl-2,3-dione)ethyl methacylate, which was placed 
with 120 ml of water in a flask and hydrolyzed by adding dropwise 59 g 
(0.58 moles) of TEA at 25.degree. C. during 10 minutes to obtain a 
triethylammonium salt of (2-methacryloyloxyethyl)2-hydroxyethyoxamic acid 
10. 
##STR26## 
This ammonium salt was completely soluble in water and identified by IR, 
which showed absorption bands at 1720 cm.sup.-1 for an ester, 1610 
cm.sup.31 1 for a carboxylic acid, and 2400.about.2800 cm.sup.-1 for a 
triethylammonium salt, an acid value of 169 (calcd. 162), and a molecular 
weight of 332. 
2 Polymerization of monomers containing an oxamic acid group 
EXAMPLE 11 
Polymerization of the monomer containing an oxamic acid group 9 (synthesis 
of homopolymer) 
In a flask similar to that used for example 9 were placed 30 ml of 
cellosolve acetate, being warmed at 100.degree. C. To this flask were 
added dropwise 20 g (0.08 moles) of the monomer containing an oxamic acid 
group in the methacylamide series 9, obtained from said example 9, and 0.3 
g of azobisisobutyronitrile (hereinafter, referred to as AIBN) during 3 
hours. Then, further reaction was carried out for 1.5 hours maintaining 
the reaction temperature at 100.degree. C. yielding an oxamic acid polymer 
in a methacrylamide series containing 40% of an unvolatile component. The 
polymer showed a water-soluble property by neutralizing with TEA. 
EXAMPLE 12 
Copolymerization of the monomer containing an oxamic acid group 9 
(synthesis of copolymer) 
A reaction similar to said example 11 was carried out with 20 ml of 
cellosolve acetate, 10.2 g (0.04 moles) of the monomer containing an 
oxamic acid group 9 obtained from said example 9, 3.8 g (0.04 moles) of 
methyl methacrylate, 5.8 g (0.05 moles) of n-butyl acrylate, and 0.9 g of 
AIBN to get an oxamic acid copolymer in a methacrylamide series containing 
50% of an unvolatile component, which showed a water-soluble property by 
neutralizing with TEA. 
EXAMPLE 13 
Polymerization of the monomer containing an oxamic acid group 10 (synthesis 
of homopolymer) 
A polymerization reaction was carried out in a way same to example 11 with 
34.5 ml of cellosolve acetate, 23 g (0.1 mole) of 
2-(1-morpholyl-2,3-dione)ethyl methacrylate obtained from said example 10, 
and 0.35 g of AIBN to get a morpholinedione polymer in a methacryl acid 
ester series containing 40% of unvolatile component. The polymer and 100 
ml of water were placed in a flask and in a similar way as in said example 
10, a hydrolysis reaction was carried out during 10 minutes at 25.degree. 
C. with 10 g (0.1 mole) of TEA yielding a trimethylammonium salt of an 
oxamic acid polymer in a methacrylic acid ester series, wherein the acid 
polymer showed an acid value of 150 and a molecular weight of 4500 
averaged by weight, and the trimethylammonium salt showed a 
water-dispersion property. 
EXAMPLE 14 
Copolymerization of the monomer containing an oxamic acid group 10 
(synthesis of copolymer) 
A reaction was carried out in a way similar to example 11 with 45 ml of 
cellosolve acetate, 6.8 g (0.03 moles) of 2-(1-morpholyl-2,3-dione)ethyl 
methacrylate obtained from said example 10, 10.0 g (0.1 mole) of methyl 
methacrylate, 15.4 g (0.12 moles) of n-butyl acrylate, 10.4 g (0.1 mole) 
of styrene, and 1.1 g of AIBN to obtain a morpholinedione copolymer in a 
methacrylic acid ester series containing 50% of an unvolatile component. 
To this solution were added 50 ml of water and 3 g (0.03 moles) of TEA to 
carry out a hydrolysis reaction and to get a triethylammonium salt of an 
oxamic acid copolymer in a methacrylic acid ester series, wherein the acid 
copolymer showed an acid value of 12 and a molecular weight of 8600 
averaged by weight, and the triethylammonium salt was not soluble in 
water. 
3 Synthesis of compounds containing an oxamic acid group and transformed 
into high molecular weight compound 
EXAMPLE 15 
Conversion of compounds containing an oxamic acid group into high molecular 
weight compounds 
In a flask similar to that used for said example 9 were placed 14.6 g (0.1 
mole) of diethyl oxalate and to this was added at a time a 50% by weight 
solution of 11.6 g (0.1 mole) of 1,6 hexamethylenediamine in ethanol and 
the mixture was stirred until the reaction temperature came to room 
temperature and then, was allowed to react at room temperature for further 
1 hour. After removal of ethanol under reduced pressure, the same 
procedure as used for example 9 gave a reaction product, which was treated 
with 5.1 g (0.05 moles) of TEA and subsequently, with 4.3 ml of 
concentrated hydrochloric acid to lead to an aimed, below-described 
polymer of the compound containing an oxamic acid group, which was 
identified as performed for example 9 by IR. An acid value of 32 and a 
molecular weight of 1753 averaged by weight were shown. 
##STR27## 
Chain-elongation reaction of polymer of the compound containing an oxamic 
acid group 
Into 17.5 g of dimethyl formamide were dissolved 17.5 g (0.01 mole) of said 
obtained polymer of the compound containing an oxamic acid group and to 
the solution obtained were added at a time 2.9 g (0.02 moles) of diethyl 
oxalate. The reaction mixture was stirred until the reaction temperature 
came to room temperature and allowed to react at room temperature for 
further 1 hour. After removal of dimethylformamide under reduced pressure, 
the reaction product obtained was treated with 1.0 g (0.01 mole) of TEA 
and subsequently, with 0.86 ml of concentrated hydrochloric acid in the 
same procedure as that for said example 9 to get an aimed chain-elongated 
polymer of the compound containing an oxamic acid group, which was as 
carried out for example 9 identified by IR and showed an acid value of 40 
and a molecular weight of 2780 averaged by weight. 
EXAMPLE 16 
Conversion of modified epoxy resin into high molecular weight compound 
In a flask equipped with a stirrer, a thermometer, a nitrogen-inlet tube, 
and a reflux condenser were placed 90 g of an epoxy resin (epoxy 
equivalent is 450) obtained from a reaction of bisphenol A with 
epichlorohydrin and then, added 60 g of MIBK to get a solution, which was 
warmed up to 120.degree. C. under nitrogen atmosphere and to which was 
added 52 g of a ketimine material obtained from a reaction of 
diethylenetriamine with MIBK. The mixture was subjected to a reaction at 
120.degree. C. for 1.5 hours and, after the reaction finished, cooled, and 
hydrolysis of the ketimine was carried out with addition of 5.8 g of water 
to obtain an epoxy resin modified by an amine A. 
Next, using a reaction apparatus similar to that used for said example 9, 
both compounds of 33 g (0.03 moles) of an amine-modified epoxy resin A, 
obtained in a way as above, and 4.4 g (0.03 moles) of diethyl oxalate were 
added at a time and allowed to react for 1 hour at room temperature. The 
reaction product obtained was treated with 2.0 g (0.02 moles) of TEA and 
subsequently, with 1.7 ml of concentrated hydrochloric acid in the same 
procedure as that for said example 9 to get an aimed epoxy resin polymer 
containing the below-described repeating structure unit: 
##STR28## 
Identification was carried out in the same way as for example 9 by IR and 
an acid value of 5 and a molecular weight of 11220 averaged by weight were 
indicated. 
4 Synthesis of the resins modified with oxamic acid 
EXAMPLE 17 
Synthesis of epoxy resin (I) modified by oxamic acid 
The reaction solution containing an amine-modified epoxy resin A, which was 
obtained after hydrolysis of the ketimine in said example 16, was added 
dropwise during 1 hour maintaining the reaction temperature at 30.degree. 
C. to 58 g (0.4 moles) of diethyloxalate placed in another flask. After 
the dropping finished, stirring was further continued for 1 hour at 
25.degree. C. and then, under reduced pressure, MIBK was removed. Then, 
the thus-obtained reaction product and 300 ml of water were placed in a 
flask and a hydrolysis reaction was carried out by adding dropwise 23 g of 
TEA (0.22 moles) during 30 minutes. To this aqueous solution was added 23 
ml of concentrated hydrochloric acid to perform reaction and an 
water-insoluble product formed was taken by decantation as a wanted 
product, that is an epoxy resin modified by oxamic acid (I) having the 
below-described structure moiety: 
##STR29## 
This modified resin (I) was neutralized with 50% TEA and, as a result, 
showed a water-soluble character. Identification was carried out with IR 
and NMR, where IR showed absorption bands at 1760 cm.sup.-1 for a 
carboxylic acid, at 1680 cm.sup.-1 for a carbonyl substituent and at 1560 
cm.sup.-1 for an amide and NMR signals appeared at 163.34 ppm and 166.17 
ppm for a carbonyl carbon. There was shown an acid value of 171 (calcd. 
160) and a molecular weight of 1392 averaged by weight. 
EXAMPLE 18 
Synthesis of epoxy resin modified with oxamic acid (II) 
To 80 ml of MIBK were dissolved 150 g of the same epoxy resin as used for 
said example 16 in the same way and the solution was warmed up to 
80.degree. C. under nitrogen atmosphere. Then, to this solution were added 
dropwise during 10 minutes 35 g (0.33 moles) of diethanolamine. This 
reaction mixture was subjected to further reaction for 3 hours at 
80.degree. C. to obtain the modified epoxy resin B which has a primary 
hydroxyl group at a terminal carbon of the epoxy resin. 
Separately, in another flask same as used for said example 9 were placed 
148 g of isophoronediisocyanate (0.67 moles), 5.1 g of DBTL, and 65 ml of 
MIBK, and the mixture obtained was warmed up to 80.degree. C. under 
nitrogen atmosphere, to which was added dropwise during 1 hour a solution 
of 106 g of N-hydroxyethylmorpholine-2,3-dione, which was obtained in the 
same procedure as that for example 10, in hot MIBK, and it was further 
subjected to reaction for 5 hours at 80.degree. C. Then, into the MIBK 
solution of above-prepared modified epoxy resin B was added dropwise 
during 30 minutes at 80.degree. C. said reaction solution of morpholine 
compound and the mixture thus-prepared was allowed to react for 2 hours at 
100.degree. C. and then, treated with distillation under reduced pressure 
to remove solvent and hydrolyzed with addition of 68 g (0.67 moles) of TEA 
and 2 liters of water to obtain a triethylammonium salt of the 
water-soluble epoxy resin modified with oxamic acid having the 
below-described modified structure moiety (II). Identification was carried 
out by IR, where showed absorption bands at 2400.about.2800 cm.sup.-1 for 
a triethylammonium salt, 1700 cm.sup.-1 for an urethane, and 1620 
cm.sup.-1 for a carboxylic acid. There were shown an acid value of 58 
(calcd. 72) and a molecular weight of 3110 averaged by weight. 
##STR30## 
EXAMPLE 19 
Synthesis of silicone resin modified with oxamic acid 
using an apparatus similar to that used for example 9, into a flask placed 
with 73 g (0.5 moles) of diethyl oxalate was added dropwise during 1.5 
hours an ethanol solution of 380 g of silicone oil (KF 864 made from 
Sinetsu Silicone Co., LTD.) maintaining reaction temperature at 30.degree. 
C. and then, the reaction mixture was stirred for 1 hour at 25.degree. C. 
to get a resin modified with an oxamic acid ester. To this ester was added 
30 ml of water and dropped 10.2 g (0.1 mol) of TEA during 30 minutes to 
carry out a hydrolysis reaction. The aqueous solution thus-obtained was 
treated with 8.3 ml of concentrated hydrochloric acid getting a wanted 
silicone resin modified with oxamic acid. Identification was carried out 
in the same way as described in example 9. The acid value was 10. 
EXAMPLE 20 
Synthesis of amino resin modified with oxamic acid 
In a similar way as used for said example 19, a reaction of 146 g (1.0 
mole) of diethyl oxalate with 89 g of a melamine resin (J-820-60 produced 
from Dainippon Inki Kagaku Kogyo Co., Ltd., molecular weight of 1960) was 
carried out to get a resin modified with an oxamic acid ester, which was 
treated with 20.4 g (0.2 moles) of TEA, water, and 16.6 ml of concentrated 
hydrochloric acid to obtain an aimed amino resin modified with oxamic 
acid. Identification was carried out by IR and the acid value was 134. 
EXAMPLE 21 
Synthesis of polyester resin modified with oxamic acid 
A reaction apparatus similar to that for example 9 was used. In a flask 
were placed 105 g of a polyester resin, which showed a hydroxyl group 
value of 220 and a molecular weight of 2100, 91.4 g (0.41 moles) of 
isophoronediisocyanate, and 300 ml of acetone and, furthermore, added 1 g 
of DBTL and the mixture was allowed to react at 60.degree. C. for 1 hour. 
The reaction product obtained was added dropwise to a mixture solution 
composed of 100 ml of acetone, 20 g of sulfuric acid, and 50 g of water 
during 30 minutes and, after addition, allowed to react for further 1 hour 
to obtain a solution of polyester resin modified with an amine, in which 
the amine moiety had a sulfuric acid salt form. Then, to this solution was 
added a mixture solution of 15.6 g of calcium hydroxide and 150 g of water 
and the mixture obtained was allowed to react at 60.degree. C. for 2 hours 
and treated with solvent removal yielding 128 g of a polyester resin 
modified with an amine, which showed an amine value of 160 and had a 
molecular weight of 3700 averaged by weight. This resin was dissolved in 
200 ml of ethanol and this solution was added dropwise in the way same as 
used for example 9 into a flask, where 292 g (2.0 moles) of diethyl 
oxalate were placed, and the mixture was allowed to react yielding an 
oxamic acid ester and then, treated with 37 g (0.37 moles) of TEA, water, 
and 30.8 ml of concentrated hydrochloric acid to get an aimed polyester 
resin modified with oxamic acid, which was identified by IR and had an 
acid value of 145. 
EXAMPLE 22 
Synthesis of polybutadiene resin modified with oxamic acid 
In the same way as for said example 19, a reaction was carried out between 
73 g (0.5 moles) of diethyl oxalate and 30 g of a polybutadiene resin 
modified with an amine, which had an amine value of 187 and a molecular 
weight of 1200, to obtain a resin modified with an oxamic acid ester, 
which was treated with 10.2 g (0.1 mole) of TEA, water, and 8.3 g of 
concentrated hydrochloric acid leading to an aimed polybutadiene resin 
modified with oxamic acid, that was identified by IR and had an acid value 
of 180. 
EXAMPLE 23 
Synthesis of polyethyleneimine resin modified with oxamic acid 
In the same way as for said example 19, a reaction was carried out between 
73 g (0.5 moles) of diethyl oxalate and 40 g of polyethyleneimine resin 
(EPOMIN P-1000 produced from Nippon Shokubai Kagaku Kogyo Co., Ltd. and 
molecular weight of 70,000) to obtain a resin modified with an oxamic acid 
ester, which was treated with 20.4 g (0.2 moles) of TEA, water, and 16.6 
ml of concentrated hydrochloric acid to obtain an aimed polyethyleneimine 
resin modified with oxamic acid, that was identified by IR and had an acid 
value of 275. 
EXAMPLE 24 
Synthesis of polyamide resin modified with oxamic acid 
In the same way as for said example 19, a reaction was carried out between 
173 g (1.2 moles) of diethyl oxalate and 90 g of a polyamide resin 
(molecular weight of 4500) to obtain a resin modified with an oxamic acid 
ester, which was similarly treated with 5.1 g (0.05 moles) of TEA, water, 
and 3.5 ml of concentrated hydrochloric acid to obtain an aimed polyamide 
resin modified with oxamic acid, that was identified by IR and had an acid 
value of 30. 
EXAMPLE 25 
Synthesis of fluororesin modified with oxamic acid 
Except that 60 g of a fluororesin modified with acrylamide (molecular 
weight 2,000) was used instead of the polyamide resin, the procedure same 
as used for example 24 gave an aimed fluororesin modified with oxamic 
acid, that was identified by IR and had an acid value of 40). 
5 Compositions containing an oxamic acid group-containing compound 
EXAMPLE 26 
Application of water-soluble resin for thermally hardening reaction (1) 
The epoxy resin modified with oxamic acid (I), 10 g, obtained from said 
example 17, 6.3 g of blockisocyanate prepared from 3 mole equivalents of 
trilenediisocyanate and 1 mole equivalent of trimethylolpropane, and 1.5 g 
of TEA were dissolved into 18 ml of water. This solution was applied on a 
tinplate and warmed at 190.degree. C. for 30 minutes to get a film having 
a thickness of 20 .mu.m. A part of this film was taken for IR measurement, 
where the carboxylic acid absorption at about 1760 cm.sup.-1 and the 
carbonyl absorption at about 1680 cm.sup.-1 observed before heating 
disappeared and, instead, a new absorption was observed at 1630 cm.sup.-1 
assignable for a formamide group. This result indicates that the oxamic 
acid, that is an ionic group, disappeared from the film after the thermal 
treatment. 
EXAMPLE 27 
Application of water-soluble resin for thermally hardening reaction 
Blockisocyanate, 9.8 g, same to that used for said example 26, and 20 g of 
the epoxy resin modified with oxamic acid (II) obtained from said example 
18 were dissolved into 20 ml of water and the procedure same as for 
example 26 gave a film having a thickness of 20 .mu.m. A part of the film 
was taken for IR measurement, where the carboxylic acid absorption at 
about 1620 cm.sup.-1 observed before heating disappeared and a new 
absorption was observed at 1660 cm.sup.-1 assignable for a formamide 
group. This result indicates that the oxamic acid, that is an ionic group, 
disappeared from the film after the thermal treatment. 
EXAMPLE 28 
Hardening reaction at low temperature with polyamine 
A mixture of 15 g of an oxamic acid copolymer in a methacrylamide series, 
obtained from said example 12, and 2.1 g of diethylenetriamine was applied 
on a tinplate and warmed for 20 minutes at 50.degree. C. to get a film 
having a thickness of 20 .mu.m. A pencil hardness examination for this 
film was carried out and the result indicates formation of a strong, solid 
film of pencil hardness H. 
EXAMPLE 29 
Application for resin composition of an organic solvent form 
A resin composition of an organic solvent form was obtained by dissolving 
into 40 parts of an organic solvent (N,N-dimethylformamide) 30 parts of an 
epoxy resin polymer modified with oxamic acid, which was obtained from 
said example 16 and had a molecular weight of 11220 and an acid value of 
5, and 10 parts of a methylated and butylated melamine resin (Nikarakku MX 
40 made from Nippon Carbide Kogyo Co., LTD). 
Said composition was applied for a plate treated with zinc phosphate so as 
to make a film of thickness 20 .mu.m. A hardened film (pencil hardness of 
2H) was obtained by baking it at 150.degree. C. for 30 minutes. 
Water-resistant and anticorrosion properties for this film was examined. 
The water-resistant property was evaluated by examining presence or 
absence of chalking and swelling for a film treated with soaking in water 
of 50.degree. C. for 48 hours. The anticorrosion property was evaluated by 
examining exfoliated width due to a tape exfoliation from a cutting part 
after a salt spray examination was carried out for 150 hours. The results 
indicate that there is no chalking and swelling for the film after soaking 
in warm water for 48 hours and that the exfliated width due to tape 
exfliation was 3 mm after salt-spray examination during 150 hours. 
Accordingly, it was found that the film obtained has a sufficient 
crosslinking density and superior water-resistant and anticorrosion 
properties. 
EXAMPLE 30 
Use as an electrodeposition coating resin 
In a flask equipped with a stirrer, a thermometer, a dropping funnel, and a 
reflux condenser were placed 50 g of the epoxy resin modified with oxamic 
acid (I), obtained from said example 17, 31.5 g of blockisocyanate as a 
hardening agent which was similar to example 26, 0.1 g of 
dibutyltin-oxide, and 7.5 g of TEA, and to this mixture was added dropwise 
504 g of water during 1 hour at 80.degree. C. to get a resin-dispersed 
solution for electrodeposition coating. This resin-dispersed solution did 
not show, after standing for 1 month at room temperature, abnormalities 
such as viscosity increase and separation and also, still had superior 
dispersion stability. 
Next, said resin-dispersed solution was placed in a stainless steel beaker 
(an anode) and, using as a cathode a test pannel plate (a cold rolling 
steel plate) deoiled with xylene, an electrodeposition experiment was 
carried out with 100 voltage and, as a result, a water-insoluble product 
was separated out on the cathode. 
Furthermore, the separated resin was heated for hardening for 30 minutes at 
190.degree. C. to obtain an uniformly electrodeposited film having a 
thickness of 25 .mu.m. The pencil hardness for this film was 2H and the 
results from capacity experiments carried out similarly to the case of 
said example 29 showed superior water-resistant, anticorrosion, and 
solvent-resisting properties. 
Use as a hardening agent for an epoxy resin 
EXAMPLE 31 
As an electrophilic resin, was used 9.3 g of an epoxy resin, obtained from 
a reaction between bisphenol A was dissolved in 15 g of MIBK with a 40% 
solution of 32 g of a homopolymer of the monomer containing an oxamic acid 
group 9, obtained from example 11, in cellosolve acetate. This solution 
was applied on a tinplate and warmed at 140.degree. C. for 3 hours to get 
a paint film of thickness 20 .mu.m. The results obtained from a pencil 
hardness examination for the paint film confirmed formation of a strong 
film of pencil hardness 2H. 
Thus, it was confirmed that a polymer of a monomer containing an oxamic 
acid group can be used as a hardening agent for an electrophilic resin. 
EXAMPLE 32 
Application as an acid-catalyst for resin hardening 
To a clear lacquer for finishing for metallics composed of 30 weight parts 
(hereinafter, referred to as .left brkt-top.part .right brkt-bot.) of an 
acryl resin of a thermally hardening type (molecular weight of 8000, an 
acid value of 10, hydroxl group value of 80), 10 parts of methylated and 
butylated melamine resin (same as for example 29), and 60 parts of an 
organic solvent (a mixture solution of xylene and isobutyl alcohol) was 
added a 40% cellosolve solution of 1.5 parts of a homopolymer ammonium 
salt of the monomer containing an oxamic acid group 9, obtained from 
example 11, to get a resin composition of an organic solvent type. 
The composition was applied on an iron plate treated with zinc phosphate to 
make a film of thickness 20 .mu.m and baked at 150.degree. C. for 30 
minutes to form a hardened paint film. 
The pencil hardness and the water-resistant and anticorrosion properties 
for this paint film obtained were evaluated as for said example 29. 
COMISON EXAMPLE 
In example 32, except that 0.5 parts of an acid hardening catalyst of an 
ammonium salt type of dodecylbenzenesulfonic acid was used instead of an 
oxamic acid derivative, a similar procedure gave a resin composition of an 
organic solvent type. 
Furthermore, in a similar way as the above, a paint film was formed from 
the composition, and property examination was similarly carried out for 
the film. Results obtained are shown in table 1. 
TABLE 1 
______________________________________ 
Example 32 
Comparison Example 
______________________________________ 
Pencil hardness 
2H 2H 
After soaking 
no change delustering observed 
in warm water 
Tape-exfoliated 
2 mm 6 mm 
width 
______________________________________ 
As seen in table 1, it was observed that the paint film, where the oxamic 
acid derivatives were used as an acid hardening catalyst, has sufficient 
crosslinking density and superior water-resistant and anticorrosion 
properties. In contrast, regarding the paint film in comparison example, 
although chalking and swelling were not observed in the film after 
treatment with soaking in warm water, delustering was found and the 
exfoliated width due to tape exfoliation after treatment with 
salt-spraying was so big as 6 mm and, therefore, it was clarified that, 
although the paint film was sufficiently crosslinked, the water-resistant 
and anticorrosion properties were lowered due to the fact that the acid 
catalyst was remaining in the paint film.