Diepoxides which may be photopolymerized in the presence or absence of a photosensitizer contain a group having conjugated unsaturation attached to a nitrogen heterocycle, such as a hydantoin or barbituric acid residue, forming part of an advanced diepoxide. The resultant photopolymer may be crosslinked by heating in the presence of a curing agent for epoxide resins. The diepoxides are of use in the production of printing plates and printed circuits, especially multilayer printed circuits.

BACKGROUND OF THE INVENTION 
This invention relates to unsaturated diepoxides which polymerise on 
exposure to actinic radiation, to methods of producing such diepoxides and 
of polymerising them by means of actinic radiation, to supports bearing 
thereon such a diepoxide in the polymerisable state, and to supports 
bearing thereon such a diepoxide polymerised by means of actinic 
radiation. 
Substances capable of becoming polymerised on exposure to actinic radiation 
are used in, for example, the preparation of printing plates for offset 
printing and of printed circuits, and for coating metals, such as in the 
manufacture of cans (see, e.g., Kosar, "Light-sensitive systems: Chemistry 
and Applications of non-silver halide Photographic Processes", Wiley, New 
York, 1965; Delzene, "Synthesis and Photocrosslinking of Light-sensitive 
Polymers", European Polym. J., Suppl. 1969, pp. 55-91; Williams, 
"Photopolymerisation and Photocrosslinking of Polymers", Forschr. Chem. 
Forsch., Vol. 13 (2), 227-250). There are various drawbacks in the 
substances presently available which may be polymerised by exposure to 
actinic radiation. Some are so unstable that they must be applied to a 
substrate only immediately prior to exposing them to actinic radiation. 
Others are relatively insensitive and need lengthy exposure to actinic 
radiation in order to become sufficiently polymerised. Others, after being 
polymerised, are not resistant to etching baths used in subsequent 
processes. 
Most previously known substances which polymerise on exposure to actinic 
radiation are used with a photosensitiser such as Michler's ketone 
(bis(p-dimethylamino)benzophenone), benzoin, or an alkyl ether of benzoin, 
to shorten the exposure time required for polymerisation. However, the 
sensitiser alters the electrical properties of the polymer, and may 
volatilise on being heated, so making it unsuitable for use in multilayer 
laminates; in the preparation of these, therefore, the polymer is removed 
after the metal etching process has taken place, which removal adds to the 
cost of the laminates and may cause damage to the surface of the metal. 
DETAILED DISCLOSURE 
We have now found that these drawbacks can be at least substantially 
overcome by the use of certain novel diepoxides, in the 
photopolymerisation of which a photosensitiser is usually not required. 
The aforesaid diepoxides contain a group having conjugated unsaturation 
attached to a nitrogen heterocycle forming part of an advanced diepoxide. 
The new diepoxides which constitute one aspect of this invention may be 
represented by the formula 
##STR1## 
where 
each R.sup.1 represents a residue of formula 
##STR2## 
R.sup.2 represents a carbonyl group, 
R.sup.3 represents a single bond joining the indicated nitrogen atom and 
carbon atom, a carbonyl group, or a methylene or ketomethylene group, 
which may be substituted by halogen atoms, alkyl or alkoxy groups of 1 to 
4 carbon atoms, or hydroxy groups, 
R.sup.4 represents a carbonyl group or a methylene or ketomethylene group, 
which may be substituted by halogen atoms, alkyl or alkoxy groups of 1 to 
4 carbon atoms, or hydroxy groups, 
R.sup.5 represents a group having ethylenic unsaturation or aromaticity in 
conjugation with the indicated double bond attached to the carbon atom 
shown in the heterocyclic ring, 
R.sup.6 represents a divalent aliphatic, aromatic, or heterocyclic group 
which may be interrupted by oxygen or sulphur atoms or secondary or 
tertiary amino groups, 
R.sup.7 and R.sup.8, which may be the same of different, each represent a 
hydrogen atom, an alkyl group of 1 to 6 carbon atoms, or together 
represent a pentamethylene or hexamethylene group, 
R.sup.9 represents a carbonyl group or a ketomethylene group, 
at least one of R.sup.3 and R.sup.4 having a carbonyl group adjacent to the 
indicated carbon atom in the heterocyclic ring and R.sup.3, R.sup.4, and 
R.sup.9 being selected such that the indicated heterocycle is a 5- or 
6-membered ring, 
X represents an oxygen or sulphur atom or a secondary or tertiary amino 
group, 
a represents zero, 1, or 2, 
b represents an integer such that the average molecular weight of the 
diepoxide of formula I is from 500 to 50,000, preferably from 2,000 to 
10,000, and 
both c are zero or, if X represents an oxygen atom, one or both may 
alternatively represent 1. 
"Aromaticity" is used herein the sense of properties associated with 
structures having (4n + 2) .pi. electrons, where n is the number of rings 
in the structure; heterocyclic groups, such as the 2-pyridyl group, which 
exhibit aromatic properties are hence included, as well as benzenoid 
groups such as the phenyl group. 
Another aspect of this invention comprises a process for the preparation of 
diepoxides of formula I which comprises advancement with b mol. of a 
heterocycle having the formula 
##STR3## 
of (b + 1) mol. of a diepoxide having the formula 
##STR4## 
or of b mol. of a diepoxide having the formula 
##STR5## 
with (b + 1) mol. of a compound having the formula where R.sup.1 - 
R.sup.5 and a have the meanings assigned above. 
One class of preferred diepoxides of formula I are those wherein R.sup.1 
represents a group of formula II, in which each X represents an oxygen 
atom, and either each c is zero, and R.sup.6 represents a straight or 
branched chain hydrocarbon group of from 2 to 6 carbon atoms or a group of 
formula 
##STR6## 
where R.sup.10 and R.sup.11, which may be the same or different, each 
represent a hydrogen atom or an alkyl group of 1 to 4 carbon atoms, or 
both c are 1 and R.sup.6 represents a group of formula 
##STR7## 
where R.sup.10 has the meaning previously assigned. 
The second class of preferred diepoxides of formula I are those wherein 
R.sup.1 represents a group of formula III, in which R.sup.9 and R.sup.4 
each represent a carbonyl group and R.sup.3 represents a single bond or a 
carbonyl group. 
Further preferred diepoxides of formula I are those wherein R.sup.5 
represents a monocyclic or bicyclic benzenoid or aromatic heterocyclic 
group, especially phenyl, .alpha.-naphthyl, 2-pyridyl, 3-pyridyl, or 
2-furyl. 
Photopolymerisable diepoxides have previously been described, for example 
in British patent specification No. 1090142 and West German 
Offenlegungsschrift No. 2300542. However, in these specifications the 
photopolymerisable unsaturated groups were attached by reaction with free 
hydroxyl groups resulting from epoxide ring opening or advancement. This 
method of introducing photopolymerisable groups is not completely 
satisfactory since it is difficult to obtain complete substitution on the 
hydroxy groups, leading to variations in photopolymerisable properties 
from batch to batch. Also, there is a risk of chain degradation and loss 
of epoxide functionality due to side reactions. Finally, reactions with 
advanced epoxide resins are difficult to carry out, since they are not 
soluble in many common organic solvents such as ethanol. 
Such problems are not encountered in making the photopolymerisable 
diepoxides of the present invention, since the group inducing 
photopolymerisability is introduced prior to advancement. 
Thus, a nitrogen heterocycle having an active methylene group, of formula 
##STR8## 
may be subjected to a Knoevenagel condensation with an unsaturated 
aldehyde of formula 
EQU R.sup.5 --CH .dbd. CH).sub.a CHO XI 
to form the substituted heterocycle of formula IV, 
where R.sup.2, R.sup.3, R.sup.4, R.sup.5, and a are as hereinbefore 
defined. 
Compounds of formula IV are, in general, known. 
This reaction may be effected by the usual method for a Knoevenagel 
condensation, i.e., in the presence of a basic catalyst such as pyridine, 
an alkali metal hydroxide, or an alkali metal salt of an organic acid in 
solution in that acid, especially sodium acetate in acetic acid. 
Usually, in the advancement reaction, the diepoxide of formula V is heated 
with the heterocycle of formula IV at a temperature of from 100.degree. to 
200.degree. C., and especially 120.degree. to 170.degree. C., and 
preferably for a period of from 1/2 to 20 hours, especially from 1 to 6 
hours. 
The reaction can be accelerated by adding a catalyst for the advancement. 
Such catalysts are, for example, alkali metal hydroxides such as sodium 
hydroxide; alkali metal halides such as lithium chloride, potassium 
chloride, or sodium chloride, bromide, or fluoride; tertiary amines such 
as triethylamine, tri-n-propylamine, N-benzyldimethylamine, 
N,N-dimethylaniline, and triethanolamine; quaternary ammonium bases such 
as benzyltrimethylammonium hydroxide; quaternary ammonium salts such as 
tetramethylammonium chloride, tetraethylammonium chloride, 
benzyltrimethylammonium chloride, benzyltrimethylammonium acetate, and 
methyltriethylammonium chloride; and hydrazines having a tertiary nitrogen 
atom, such as 1,1-dimethylhydrazine, which can also be employed in their 
quaternised form. 
An inert solvent may also be present. 2-Ethoxyethanol is particularly 
suitable. 
Depending on the choice of the starting substances, the reaction in some 
cases takes place quantitatively so rapidly that no addition of catalyst 
is necessary. Whilst the starting materials are generally mixed with one 
another at room temperature and are then brought to the reaction 
temperature, it is advantageous in the case of very reactive components if 
the diepoxide of formula V is first introduced and heated by itself to the 
requisite reaction temperature and the heterocycle of formula IV is then 
gradually added in small portions. The progress of the reaction up to the 
end product having a defined epoxide group content which essentially 
remains constant can be followed by titration of the epoxide groups using 
samples taken during the reaction. 
Such advancement reactions are known (see, e.g., British patent 
specifications Nos. 1230889 and 1237610). 
As examples of suitable diepoxides of formula V may be mentioned various 
diglycidyl compounds such as diglycidyl esters obtainable by reaction of a 
compound containing two carboxylic acid groups per molecule with 
epichlorohydrin or glycerol dichlorohydrin in the presence of an alkali. 
These diglycidyl esters may be derived from aliphatic carboxylic acids, 
e.g., glutaric acid, adipic acid, pimelic acid, suberic acid, azelic acid, 
sebacic acid, or dimerised linoleic acid; from cycloaliphatic carboxylic 
acids such as tetrahydrophthalic acid, 4-methyltetrahydrophthalic acid, 
hexahydrophthalic acid, and 4-methylhexahydrophthalic acid; and from 
aromatic carboxylic acids such as phthalic acid, isophthalic acid, and 
terephthalic acid. 
Further examples of suitable diglycidyl compounds are glycidyl ethers 
obtainable by reaction of a compound containing two alcoholic hydroxyl or 
phenolic hydroxyl groups per molecule with epichlorohydrin or glycerol 
dichlorohydrin under alkaline conditions, or, alternatively, in the 
presence of an acidic catalyst and subsequent treatment with alkali. These 
ethers may be made from acyclic alcohols such as ethylene glycol, 
diethylene glycol, and higher poly(oxyethylene) glycols, propane-1,2-diol 
and poly(oxypropylene) glycols, propane-1,3-diol, butane-1,4-diol, 
poly(oxytetramethylene) glycols, pentane-1,5-diol, and hexane-1,6-diol; 
from cycloaliphatic alcohols such as resorcitol, quinitol, 
bis(4-hydroxycyclohexyl)methane, 2,2-bis(4-hydroxycyclohexyl)propane, and 
1,1-bis(hydroxymethyl)cyclohex-3-ene; and from alcohols having aromatic 
nuclei, such as N,N-bis(2-hydroxyethyl)aniline and 
p,p'-bis(2-hydroxyethylamino)diphenylmethane. Or they may be made from 
mononuclear phenols, such as resorcinol and hydroquinone, and from 
polynuclear phenols, such as bis(4-hydroxyphenyl)methane, 
4,4'-dihydroxydiphenyl, bis(4-hydroxyphenyl)sulphone, 
2,2-bis(4-hydroxyphenyl)propane (otherwise known as bisphenol A), and 
2,2-bis(3,5-dibromo-4-hydroxyphenyl)propane. 
Suitable di(N-glycidyl) compounds include those obtained by 
dehydrochlorination of the reaction products of epichlorohydrin with 
amines containing two amino-hydrogen atoms, such as aniline, n-butylamine, 
and bis(4-methylaminophenyl)methane; and N,N'-diglycidyl derivatives of 
cyclic ureas, such as those of hydantoins, uracils, dihydrouracils, 
parabanic acid, bis(hydantoin-1-yl)alkanes, ethyleneureas 
(imidazolidin-2-ones), and 1,3-propyleneureas 
(hexahydro-2H-pyrimidin-2-ones). 
Examples of suitable di(S-glycidyl) compounds are di-S-glycidyl derivatives 
of dithiols such as ethane-1,2-dithiol and bis(4-mercaptomethylphenyl) 
ether. 
Epoxide resins having the glycidyl groups attached to different kinds of 
hetero atoms may be employed, e.g., the glycidyl ether-glycidyl ester of 
salicylic acid and 
N-glycidyl-N'-(2-glycidyloxypropyl)-5,5-dimethylhydantoin. 
Alternatively, heterocycles of formula IV are converted into 
N,N'-diglycidyl compounds of formula VI (which are believed to be, in 
general, novel) by methods known per se for the formation of their 
N,N'-diglycidyl derivatives from hydantoins and similar heterocycles and, 
as already indicated, b mol of such a diepoxide is advanced by means of a 
compound of formula VII. The advancement may be carried out in a similar 
manner to that of the diepoxide of formula V with the heterocycle of 
formula IV; thus, the compounds of formulae VII and VI may be heated 
together at a temperature of from 100.degree. to 200.degree. C., 
especially from 120.degree. to 170.degree. C., and preferably from 1/2 to 
20 hours, especially 1 to 6 hours, and preferably an advancement catalyst 
such as those specified above is employed. 
The unsaturated diepoxides of the present invention are polymerised by 
exposure to actinic radiation, preferably of wavelength 200-600 nm. If 
desired, the irradiated material may then be crosslinked through the 
epoxide groups by reaction with a polycarboxylic acid anhydride or other 
heat-curing agent for expoxide resins, expecially a latent curing agent, 
i.e., one which has little or no effect at room temperature but which 
rapidly induces crosslinking when a certain threshold temperature is 
exceeded, e.g., dicyandiamide, a boron difluoride chelate, or a complex of 
a tertiary amine with boron trifluoride or with boron trichloride. Such 
additional cross-linking often enhances the adhesion of the polymerised 
composition to the support. 
The unsaturated diepoxides of this invention are of particular value in the 
production of printing plates and printed circuits, especially multilayer 
printed circuits which can be prepared without removal of the 
photopolymerised diepoxide. A layer of the diepoxide may be applied to a 
support by coating the support with a solution of the diepoxide in any 
convenient solvent, e.g., cyclohexanone, 2-ethoxyethanol, or a mixture of 
toluene and acetone or ethyl methyl ketone, and allowing or causing the 
solvent to evaporate; the layer may be applied by dipping, spinning or 
spin-coating (a process in which the material in put on a plate which is 
then rotated at high speed to distribute the material over it), spraying, 
or by means of a roller. 
This invention also includes a plate sensitive to actinic radiation 
comprising a support, which may be of, for example, copper, aluminum or 
other metal, paper, synthetic resin, or glass, carrying a layer of such a 
diepoxide, admixed if desired with a heat-curing agent for epoxide resins, 
also a support bearing upon its surface such a diepoxide which has been 
polymerised by exposure to actinic radiation, and further, if desired, 
crosslinked by means of a heat-curing agent for epoxide resins. It also 
provides a method of polymerising such a diepoxide which comprises 
subjecting a plate carrying a layer of the diepoxide to actinic radiation, 
optionally imagewise as through a negative, and removing the unpolymerised 
portions, if any, of the diepoxide by means of a solvent. 
The coating of the diepoxide should be applied to the support so that, 
uppon drying, its thickness will be in the range of from about 1 to 250 
.mu.m. The thickness of the polymerisable layer is a direct function of 
the thickness desired in the relief image, which will depend on the 
subject being reproduced and particularly on the extent of the 
non-printing areas. The wet polymer coating may be dried by air drying or 
by any other known drying technique, and the polymerisable system may then 
be stored until required for use. 
The polymerisable coatings can be insolubilised by exposure to actinic 
radiation through an image-bearing transparency consisting of 
substantially opaque and transparent areas. Suitable sources of actinic 
radiation include carbon arcs, mercury vapour arcs, fluorescent lamps with 
phosphors emitting ultra-violet light, argon and xenon glow lamps, 
tungsten lamps, and photographic flood lamps. Of these, mercury vapour 
arcs, particularly sun lamps, fluorescent sun lamps, and metal halide 
lamps are most suitable. The time required for the exposure of the 
diepoxide will depend upon a variety of factors which include, for 
example, the individual diepoxide being utilised, the thickness of the 
coating, the type of light source, and its distance from the coating. 
Subsequent to the exposure the coatings are "developed" by being washed 
with a suitable liquid, such as perchloroethylene, methylene chloride, 
ethylene dichloride, chloroform, actone, ethyl methyl ketone, 
cyclohexanone, n-propanol, ethanol, toluene, benzene, ethyl acetate, 
dimethylformamide, and mixtures thereof, to dissolve and remove that 
portion of the coating which was not polymerised by exposure to actinic 
radiation. Liquids used for this operation must be selected with care 
since they should have good solvent action on the unexposed areas yet have 
little effect upon either the polymerised diepoxide or the substrate. The 
developing solvent should normally be allowed to remain in contact with 
the coating for from about 30 seconds to 3 minutes, depending upon which 
solvent is utilised. The developed polymer coating should next be rinsed 
with fresh solvent and dried. 
If appropriate, such as in the production of printed circuits where the 
support is of copper or of other suitable electrically-conducting metal, 
the exposed metal is etched in a conventional manner using, e.g., ferric 
chloride or ammonium persulphate solutions. 
As already indicated, the diepoxide is preferably crosslinked through its 
epoxide groups after exposure to actinic radiation. To crosslink the 
composition it is heated after development, generally at a temperature of 
from 100.degree. to 200.degree. C.

The following Examples illustrate the invention. All temperatures are in 
degrees Celsius. Epoxide contents were measured by titration against a 
0.1N solution of perchloric acid in glacial acetic acid in the presence of 
excess of tetraethylammonium bromide, crystal violet being used as the 
indicator. By the term `solids content` is meant the percentage of 
material left after a 2g sample has been heated in an open dish at 
120.degree. for 3 hours. 
EXAMPLE 1 
A solution of hydantoin (40 g), freshly distilled cinnamaldehyde (50 g), 
and fused sodium acetate (80 g) in acetic acid (160 ml) was heated to 
reflux for 11/2 hours. The solution was poured into cold water (1.5 l) to 
precipitate the orange product, which was removed by filtration. This 
product was washed with water until neutral and then with cold ethanol to 
give 69 g (85% theoretical yield) of virtually pure product. Before use, 
the product was recrystallised from ethanol to give yellow crystals of 
5-cinnamylidenehydantoin, m.p. 268.degree.-270.degree. (decomp.), the 
infra-red spectrum of which showed the expected main peaks at 1750, 1700, 
1640, 1390, 1350, 1020, 970, 895, 825, 750, 690, and 655 cm.sup.-1. 
Found: C, 67.05%, H, 4.52%; N, 12.8%. C.sub.12 H.sub.10 N.sub.2 O.sub.2 
requires C, 67.29%; H, 4.67%; N, 13.08%. 
The structure assigned was confirmed by C.sup.13 NMR data. 
A mixture of 5-cinnamylidenehydantoin (20 g), 1,3-diglycidyl-5, 
5-dimethylhydantoin of epoxide content 8.12 equiv./kg (24 g), 
tetramethylammonium chloride (0.2 g), and 2-ethoxyethanol (66 g) was 
stirred at 120.degree. for 5 hours, by which time the epoxide content of 
the product was 0.55 equiv./kg (based on the solids content of the 
solution). 
The product is substantially of formula I in which R.sup.1 denotes a group 
of formula 
##STR9## 
R.sup.2 and R.sup.4 denote carbonyl groups, R.sup.3 denotes a single bond, 
R.sup.5 denotes a phenyl group, a is 1, and b is an integer of average 
value 8. 
A copper-clad laminate was coated with a portion of the solution, and the 
solvent was allowed to evaporate, leaving a film about 10 .mu.m thick. 
This film was irradiated for 3 minutes through a negative using a 500 watt 
medium pressure mercury lamp at a distance of 230 mm. After irradiation, 
the image was developed by washing with 2-ethoxyethanol at 20.degree., 
which removed the unexposed areas of the film. Uncoated copper areas were 
then etched using an aqueous solution of ferric chloride (60% w/v 
FeCl.sub.3) containing concentrated hydrochloric acid (10% v/v), leaving a 
good relief image. 
EXAMPLE 2 
A mixture of 5-cinnamylidenehydantoin (4.0 g), 
2,2-bis(4-glycidyloxyphenyl)propane of epoxide content 5.3 equiv./kg (7.0 
g), tetramethylammonium chloride (0.02 g), and 2-ethoxyethanol (16.6 g) 
was stirred at 120.degree. for 3 hours, by which time the epoxide content 
of the product was 0.51 equiv./kg (based on the solids content of the 
solution). 
The product is substantially of formula I in which R.sup.1 denotes a group 
of formula 
##STR10## 
R.sup.2 and R.sup.4 both denote carbonyl groups, R.sup.3 denotes a single 
bond, R.sup.5 denotes a phenyl group, a is 1, and b is an integer of 
average value 7. 
The product was tested as described in Example 1, and a good relief image 
was obtained after 6 minutes' irradiation and development in 
2-ethoxyethanol. 
EXAMPLE 3 
A solution of hydantoin (10 g), fused sodium acetate (20 g), and freshly 
distilled furfural (12 g) in acetic acid (40 ml) was heated under reflux 
for 11/4 hours. The dark solution was poured into cold water (400 ml) to 
precipitate the dark green/yellow product, which was washed with water 
until neutral and then with cold ethanol to give 14 g (80% theoretical 
yield) of 5-furfurylidenehydantoin m.p. 232.degree.-5.degree. (decomp.) 
(H. L. Wheeler and C. Hoffman, Amer. Chem. J., 1911, 45, 368, quote m.p. 
232.degree..) The material was used without further purification. 
A mixture of 5-furfurylidenehydantoin (5.0 g), 
1,3-diglycidyl-5,5-dimethylhydantoin of epoxide content 8.2 equiv./kg (7.0 
g), tetramethylammonium chloride (0.02 g), and 2-ethoxyethanol (20.0 g) 
was stirred at 120.degree. for 2 hours, by which time the epoxide content 
of the product (based on the solids content of the solution) was 0.6 
equiv./kg. 
The product is substantially of formula I in which R.sup.1 denotes a group 
of formula XII, R.sup.2 and R.sup.4 both denote carbonyl groups, R.sup.3 
denotes a single bond, R.sup.5 denotes a 2-furyl group, a is zero, and b 
is an integer of average value 8. 
The solution was tested as described in Example 1, and a good relief image 
was obtained after 6 minutes' irradiation and development in a 1:1 (v/v) 
mixture of 2-ethoxyethanol and dimethylformamide. 
EXAMPLE 4 
Barbituric acid (10.0 g) was dissolved in water (150 ml) at reflux, and the 
solution was stirred vigorously and maintained at just below refluxing 
point while freshly distilled cinnamaldehyde (10.3 g) was added slowly: a 
yellow precipitate formed almost immediately. After the addition, the 
mixture was stirred and maintained at just below refluxing point for 1 
hour to complete the reaction. The product was filtered off, washed 
several times with hot water and then with cold ethanol, and then dried to 
give yellow 5-cinnamylidenebarbituric acid (18 g, 96% theoretical yield) 
m.p. 268.degree.-70.degree. (decomp). 
Found: C, 64.19%; H, 4.41%; N, 11.50%. C.sub.13 H.sub.10 N.sub.2 O.sub.3 
requires C, 64.46%; H, 4.13%; N, 11.57%. 
I.r. spectrum (main peaks): 1750, 1660, 1600, 1575, 1430, 1410, 1390, 1315, 
1220, 1178, 1000, 795, 752, 685 cm.sup.-1. 
The structure assigned was confirmed by C.sup.13 NMR data. 
The material was pure enough to use without further purification. 
A mixture of 5-cinnamylidenebarbituric acid (6.0 g), butane-1,4-diol 
diglycidyl ether of epoxide content 9.12 equiv./kg (5.4 g), 
tetramethylammonium chloride (0.02 g), 2-ethoxyethanol (17 g), and 
dimethylformamide (2.0 g) was stirred at 130.degree. for 51/2 hours, by 
which time the epoxide content of the product was 0.7 equiv./kg (based on 
the solids content of the solution). 
The product is substantially of formula I in which R.sup.1 denotes a group 
EQU --O--(CH.sub.2).sub.4 --O-- XIV 
r.sup.2, r.sup.3, and R.sup.4 all denote carbonyl groups, R.sup.5 denotes a 
phenyl group, a is 1, and b is an integer of average value 6. 
The solution was tested according to Example 1, and a good relief image was 
obtained after 6 minutes' irradiation and development in 2-ethoxyethanol. 
EXAMPLE 5 
To 2 g of the resin solution prepared in Example 1 was added dicyandiamide 
(0.04 g). A copper-clad laminate was coated with the composition, and the 
solvent was allowed to evaporate, leaving a film. This film was irradiated 
through a negative, as described in Example 1, and developed in 
2-ethoxyethanol to give a good relief image. The plate was heated at 
180.degree. for 2 hours: the coating of the polymer in the image areas had 
very good adhesion to the copper, and very good solvent resistance; thus, 
it passed the standard acetone rub test, i.e., twenty rubs with a 
cotton-wool swab soaked in acetone did not remove any of the coating. 
EXAMPLE 6 
A mixture of 5-cinnamylidenehydantoin (2.1 g; prepared as described in 
Example 1), diglycidyl hexahydrophthalate of epoxide content 6.5 equiv./kg 
(3.5 g), tetramethylammonium chloride (0.02 g), and 2-ethoxyethanol (13.0 
g) was stirred at 130.degree. for 6 hours, by which time the epoxide 
content of the product was 0.2 equiv./kg (based on the solids content of 
the solution). 
The product is substantially of formula I where R.sup.1 denotes a group of 
formula 
##STR11## 
R.sup.2 and R.sup.4 both denote carbonyl groups, R.sup.3 denotes a single 
bond, R.sup.5 denotes a phenyl group, a denotes 1, and b denotes an 
integer of average value 21. 
The solution was tested according to Example 1, and a good relief image was 
obtained after 15 minutes' irradiation and development in cyclohexanone. 
EXAMPLE 7 
A mixture of hydantoin (5.0g), sorbaldehyde (4.8g), water (30 ml), and 
ethanol (30 ml) was stirred and heated to 70.degree., giving a clear 
solution. Ethanolamine (4.6g) in ethanol (10 ml) was added dropwise at 
70.degree., and after a few minutes the solution had turned deep red. 
After the addition, the solution was stirred at 85.degree. for 4 hours. 
Concentrated hydrochloric acid was then added to the solution until its pH 
was approximately 4, and on cooling a yellow product crystallized; this 
was removed by filtration. The product was recrystallized from ethanol to 
give yellow 5-(2',4'-hexadienylidene)hydantoin m.p. 234.degree.-5.degree.. 
I.r. spectrum (main peaks): 1720, 1650, 1615, 1585, 1360, 1320, 1210, 1090, 
980, 880, 760, 700, 645 cm.sup.-1. 
A mixture of 5-(2',4'-hexadienylidene)hydantoin (2.2 g), 
1,3-diglycidyl-5,5-dimethylhydantoin of epoxide content 8.12 equiv./kg 
(3.1 g), tetramethylammonium chloride (0.02 g), and 2-ethoxyethanol (12.4 
g) was stirred at 130.degree. for 4 hours and at 105.degree. for 16 hours, 
by which time the epoxide content of the product was 0.80 equiv./kg (based 
on the solids content of the solution). 
The product is substantially of formula I where R.sup.1 denotes a group of 
formula XII, 
R.sup.2 and R.sup.4 both denote carbonyl groups, R.sup.3 denotes a single 
bond, R.sup.5 denotes a group --CH.dbd.CH--CH.sub.3, a is 1, and b is an 
integer of average value 6. 
Michler's ketone (0.02 g) was dissolved in 2 g of the solution and the 
composition was tested as described in Example 1. A good relief image was 
obtained after 20 minutes' irradiation and development in cyclohexanone. 
EXAMPLE 8 
To a suspension of 5-cinnamylidenehydantoin, (9.0 g; prepared as described 
in Example 1) in epichlorohydrin (200 g) was added a solution of 
tetramethylammonium chloride (0.06 g) in water (0.1 g). The mixture was 
stirred vigorously and heated, and the pressure was reduced so that the 
solvent refluxed at 55.degree.. Sodium hydroxide (3.9g) in 50% aqueous 
solution was added dropwise over a period of 2 hours, and water formed 
during condensation was removed from the azeotropic mixture. Refluxing was 
continued at 55.degree. for a further 2 hours. 
The product was washed several times with water until clear and neutral, 
and then dried (MgSO.sub.4). Removal of the solvent gave 
1,3-diglycidyl-5-cinnamylidenehydantoin (12.5 g) of epoxide content 5.3 
equiv./kg, as a dark orange solid. 
A mixture of the above product (3.6 g), 5,5-dimethylhydantoin (1.0 g), 
tetramethylammonium chloride (0.01 g), and 2-ethoxyethanol (9 g) was 
stirred at 130.degree. for 4 hours, by which time the epoxide content of 
the product was 0.65 equiv./kg (based on the solids content of the 
solution) 
The product is substantially the same as that described in Example 1, but 
in which b is an integer of average value 6. 
The solution was tested as described in Example 1, and a relief image was 
obtainted after 15 minutes' irradiation and development in chloroform.