 |
Description  |
|
|
This invention relates to a process for preparing binding agents for
printing inks, in particular printing inks for off-set and letterpress
printing.
It has been proposed to react maleic anhydride with hydrocarbon resins and
to thenreact the adducts with compounds of metals from group II of the
Periodic Table. Such resins do indeed show distinctly more favourable
behaviour in intaglio printing than the starting products, but owing to
their incompatibility with mineral oils rich in aliphatics they are
ill-suited to letterpress printing and offset printing.
It has also been proposed to use adducts of maleic anhydride and
hydrocarbon resins low in indene as binding agents. However these adducts
while again having improved properties over the starting resins are only
suitable for intaglio printing.
In the search for binding agents not only for toluene intaglio printing,
but also for paints and offset printing inks, it has been suggested to
modify hydrocarbon resins with phenol-formaldehyde condensation products,
preferably also incorporating maleic anhydride. In order to obtain a
binding agent which is compatible with mineral oils, the product must,
according to the aforementioned process, be boiled with a quantity of a
drying oil at least equal to the quantity of modified hydrocarbon resin.
Such fatty binding agents are indeed suitable for the preparation of
letterpress and offset printing inks but not for the known offset roller
printing inks.
Binding agents prepared from hydrocarbon resins by reaction with
tert.-butylphenol, diphenylolpropane, formaldehyde and oxalic acid as acid
catalyst have also been described. These binding agents may be used in
toluene intaglio printing inks and in offset printing inks providing they
are sufficiently compatible with mineral oils which are rich in
aliphatics. Offset roller printing inks prepared therefrom adhere more
strongly to paper than many known printing inks consisting of modified
natural resinic acids. However, if such fatty binding agents are highly
cross-linked, they generally show a lack of compatibility with mineral
oils rich in aliphatics.
According to the present invention we now provide a process for the
preparation of a printing ink binding agent having a melting point of
130.degree. to 225.degree. C., preferably 145.degree. to 200.degree. C.,
for use in heat-drying printing inks which comprises simultaneously
reacting (1) a hydrocarbon resin containing a predominant number of units
of cyclopentadiene or derivatives thereof and having a bromine number in
the range 50 to 200, preferably 80 to 160, (2) a phenol-aldehyde component
comprising a phenol-aldeyhde condensation product or precursors therefor,
the phenol content of which consists predominantly of at least one phenol
substituted by a hydrocarbon group and (3) a natural resinic acid or an
ester or metal salt thereof, said reaction mixture being free from
.alpha.,.beta.-olefinically unsaturated dicarboxylic acids or derivatives
thereof. At least one olefinically unsaturated monomer may advantageously
also be incorporated. In general the binding agents prepared according to
the invention not only melt at a relatively high temperature but in
addition are also particularly compatible with aliphatic solvents,
especially mineral oils rich in aliphatics. Compatible mixtures containing
binder: solvent in ratios higher than 1 : 1, for example 1 : 2 and above
have been obtained. Good compatibility with odourless mineral oils (which
are acceptable from an environmental viewpoint) is particularly desirable
for the preparation of printing varnishes. Owing to the good solvent
compatibility of the products, printing varnishes with good flow
properties can be produced, which are suitable, for example, in the
manufacture of offset roller printing inks. Moreover the product are
lighter in colour than would be expected.
The hydrocarbon resin used as starting resin is generally prepared by
thermal polymerisation, and contains units of cyclopentadiene and
derivatives thereof such as methyl-cyclopentadiene and dicyclopentadiene.
The starting resins are generally synthesised from hydrocarbon fractions
boiling in the range from 20.degree. to 180.degree.,preferably 30.degree.
to 165.degree. C. The hydrocarbon fraction after synthesis of the starting
resin often contains olefinically unsaturated monomers, for example
propylene, butene, butadiene, pentene, isoprene, cyclopentene and
cyclohexene, which may if desired, be incorporated into the binding agent.
These monomers, however, should amount to at most 10% by weight referred
to the starting hydrocarbon resin.
Natural resinic acids which may be used are for example colophony, tall oil
resinic acid and wood resin. Natural resinic acids with a bromine number
of 200 to 280, preferably at least 250, are preferred. They are generally
used in amounts of from 3to 300, preferably 40 to 100% by weight, based on
the hydrocarbon resin. The properties of the reaction products according
to the invention for example the viscosity and solubility, may be
controlled by means of the choice and amount of natural resin used.
The natural resins may be used as such or in the form of their esters or
resinates. The esters may be prepared, for example, by at least partial
esterification with mono-and/or polyhydric alcohols with up to 12 C-atoms,
preferably methanol, ethanol, propanol, the butanols, pentanols, hexanols,
heptanols, octanols, nonanols, dodecanols. diols with 2 to 8 carbon atoms,
such as ethanediol and the propane-, butane-, pentane- and hexane-diols,
glycerol, trimethylolethane, trimethylolpropane and pentaerythritol. The
metal resinates may be prepared for example by at least partial
neutralisation under salt formation with compounds of metals of group II
and/or III of the Periodic Table, e.g. the oxides, hydroxides, carbonates
and acetates of zinc, calcium and/or magnesium. On the other hand, the
acid groups of the natural resin in the binder may be subsequently reacted
in known manner forming resinates and/or esters, but the first-mentioned
possibility is preferred.
An important advantage of the co-use of natural resinic acid components is
that carboxyl groups are introduced which during the reaction in the heat
react with metal salts, for example a catalyst for the phenol-aldehyde
condensation reaction, to form soluble metal resinates. Thus the presence
of insoluble, detrimental salt-like components in the end products which
would have to be removed, for example by washing, is avoided. The presence
of natural resinic acids permits the use as phenol-aldehyde components of
phenol resols which have not been neutralised and thus still contain
catalyst, often in quantities up to 4.5% by weight based on the phenol
content. In addition washing of the reaction product is also avoided and
thus the production of large quantities of waste water detrimental to the
environment is eliminated.
It is also possible to modify resols or their uncondensed components each
being free from catalysts and eventually to esterify and/or neutralize the
natural resin component.
It is further possible to carry out the reaction in the presence of an
alcohol and thus to esterify at least some of the resin acid groups during
the reaction. Alternatively the acid groups may be esterified and/or
neutralised at a later stage.
The phenol-aldehyde component may be for example a novolak or resol which
may be based on phenol, but in a minor amount, or the uncondensed
components of such resins. The phenol component contains at least one
phenol substituted by at least one hydrocarbon group, for example phenols
substituted by alkyl groups containing 1 to 12 carbon atoms, or by aryl or
aralkyl groups, such as the cresols (e.g. m-cresol), 1,3,5-xylenol,
isopropyl-, p-tert.-butyl, amyl, octyl-, and nonyl-phenol, phenylphenol,
cumylphenol and diphenylolpropane, phenols substituted by other
carbocyclic groups such as those obtained by addition of olefinically
unsaturated monomers such as styrene, .alpha.-methyl-styrene,
.alpha.-chlorostyrene, vinyltoluene, or cyclopentadiene to phenols, in
conventional manner, using acid catalysts. The phenol component
advantageously contains a predominant proportion of alkyl or
aralkylphenols, and thus the desired compatibility of the reaction
products with aliphatic hydrocarbons is attained. The preferred resins are
those made from bifunctional phenols, that is, phenols in which two of the
three o- and p-positions to the phenolic hydroxyl group are free and
reactive. Trifunctional and higher functional phenols or the phenol resins
produced therefrom are generally used only together with bifunctional
phenolic components. e.g. the above-named alkylphenols and/or the addition
products of olefinically unsaturated monomers to the phenols. The at least
tri- and higher functional phenols such as phenol, diphenylolpropane, are
generally only used in quantities of at most 10, preferably up to 5 % by
weight, based on the total quantity of phenols. By controlling the content
of trifunctional phenols, the solubility of the end products, particularly
in aliphatic hydrocarbons, can be controlled. On the other hand, by
raising the trifunctional phenol content to 10 %, the solubility of the
products in aromatic hydrocarbons can be increased.
The aldehyde components of the phenol-aldehyde component is preferably an
aldehyde with 1 to 7 C-atoms, particularly formaldehyde in monomeric or
polymeric form. Other aldehydes, such as acetaldehyde, butyraldehyde,
isobutyraldehyde, benzaldehyde and furfural, may also be used. The molar
ratio of phenol:aldehyde in the phenol aldehyde component (including
condensed phenol and aldehyde) may vary within wide limits, e.g. 1: (0.9
to 3.5), preferably 1:(1 to 2.5). Any unreached aldehyde or phenol may be
distilled off at the end of the reaction.
By the nature and quantity of the phenol-aldehyde components in the
starting mixture, the viscosity of the end products can be conveniently
controlled. The use of liquid resols is preferred. The phenol-aldehyde
component may on the other hand comprise mixed condensates of various
phenols or resols modified by reaction with unsaturated monomers, e.g. the
afore-mentioned monomers, in which case, further modification of the
starting resin or of the end product with olefinic monomers is no longer
necessary, but is precluded. However, compatibility with aliphatic
hydrocarbons is reduced by a higher proportion of added monomers. To
guarantee adequate compatibility, the proportion of monomers added to the
phenol resin is therefore preferably not more than 5% by weight. The
phenol content of the binding agent prepared wherein the phenol is
preferably present in a bound form in the phenol resin component is
preferably from 25 to 300% more preferably up to 100% by weight, based on
the starting hydrocarbon resin. Advantageously an alkylphenol-aldehyde
component contains at least 25, preferably at least 75% by weight
(referred to the total phenol content) of butylphenol. The embodiment has
the advantage that especially high-melting products are obtained which are
compatible with mineral oils rich in aliphatics for example in ratios of
at least 1 : 1, and even 1 : 2.
According to the invention, phenol-aldehyde condensation products
especially those of alkylphenols, are preferably reacted in amounts up to
100% by weight, based on the starting hydrocarbon resin. In this way,
adequate solubility of the binding agents, in particular in aliphatic
hydrocarbons, is ensured.
The reaction is preferably effected at elevated temperatures in a melt or
in solution. Any olefinic monomer components may conveniently serve as
solvent.
It is not absolutely necessary to effect the process according to the
invention in the presence of a catalyst, but in general an alkaline
catalyst is present for example one or more of the catalysts
conventionally used in phenol resin technology such as, e.g. sodium,
potassium, magnesium, calcium, barium and zinc hydroxides, and the oxides,
carbonates and acetates of the aforementioned metals and especially of
zinc, magnesium and calcium either alone or in admixture. The amount of
catalyst used is generally up to one gram-equivalent per mol of phenol, in
particular 0.1 to 4.5% preferably 0.2 to 4% by weight, based on the total
phenol content. The presence of alkaline catalysts is also preferred in
the embodiment of the process of the invention according to which a
phenol-aldehyde condensation resin prepared by acid condensation is used
and the reaction is then performed, e.g. in a direct process with the
above mentioned alkaline catalyst.
It is also possible to use as the phenol-aldehyde component resols which
are prepared in the presence of substantially larger amounts of catalyst,
for example one gram-equivalent of potassium hydroxide per mol of phenol.
However such resins should be neutralised after the condensation reaction
and washed free of salt components. If large quantities of phenols in the
form of alkylphenols and/or aralkylphenol-formaldehyde condensates or
their precursors are used, then the reactivity of the phenol resins is
generally suppressed e.g. by condensing with less than the usual amount of
formaldehyde, in order to keep the viscosity of the products within
certain limits.
Conveniently, the reaction is performed in the presence of a solvent.
Suitable solvents include for example the olefinically unsaturated
monomers remaining in the hydrocarbon fraction after the synthesis of the
starting hydrocarbon resin. Other solvents, for example toluene, xylene,
mixtures of aliphatic and/or aromatic hydrocarbons, e.g. in the form of
mineral oils or fractions from the distillations of crude oil, may be used
together with or instead of these unsaturated monomers. However, inert
solvents are preferred. As a rule, the solvent is removed after reaction,
conveniently by distillation. In many cases, however, it may be desirable
to leave at least part of the solvent, particularly mineral oils rich in
aliphatics --e.g. those boiling in the range 240.degree. to 320.degree. C.
in the products, in order to vary the melting point and viscosity of the
resin product as desired. Thus the reaction product may be obtained in the
form of a solid or liquid resin (resin-mineral oil varnish) or as a
solution in mineral oil. On the other hand, it is also possible to dilute
particularly high melting products of the invention after the reaction,
e.g. with mineral oils rich in aliphatics, and thus obtain a lowering of
the melting point and a reduction of viscosity.
The reaction is generally effected at normal pressure, and at temperatures
from 100.degree. to 270.degree. C., preferably 120 to 260.degree. C.,
usually at least 170.degree. C., and especially at 200.degree. to
220.degree. C. The reaction may also be effected under increased or
reduced pressure. Towards the end of the reaction, the temperature is
generally raised to removed any solvent, e.g. the reaction mixture may be
heated to 250.degree. to 270.degree. C.
The products prepared according to the invention are high-melting resins.
They are compatible with mineral oils, generally in ratios of at least
1:1, and often above 1:2, but also release the components of these
solvents quickly. The reaction products according to the invention have a
melting range of 130.degree. to 225.degree. C., preferably 145.degree. to
200.degree. C. The viscosity of the products (in 50% toluene
solution/20.degree. C.) is generally 100 to 600, preferably 150 to 300 cP,
but may if required be above or below this range. Products having a
melting point and viscosity within the given ranges are particularly
adapted for use as printing ink binding agents. Also, products with an
acid number of 10 to 40, preferably 20 to 35 behave particularly
favourably.
Solutions of the products in mineral oils rich in aliphatics may be used as
varnishes for the manufacture of paints and printing inks. For this
purpose they are generally easily processed with alkyd resins, driers,
such as naphthenates or octoates of cobalt, zinc, manganese and lead, and
pigments, and optionally also withgenerally up to 1% by weight -- of
chelate-forming metal compounds, such as titanates and aluminium
alcoholates, to form heat-drying printing inks in particular for offset
roller printing but also for letterpress printing. These inks dry
considerably faster and also dry at lower temperatures than the hitherto
known binding agents for offset roller printing. The presence of
chelate-forming metal compounds serves to control gel formation and thus
also contributes to faster drying and a better stand on the paper.
For letterpress printing inks, the products are preferably modified either
by chemical reaction or more conveniently by simple admixture with a large
quantity of drying oils or alkyd resins or the like, in order to increase
the fatty acid content so that oxidative drying proceeds better. For
intaglio printing inks, particularly toluene intaglio printing inks,
compatibility may, on the other hand, be limited as required by, for
example, incorporating maleic anhydride or a higher proportion of at least
trifunctional phenols, such as diphenylolpropane, phenolformaldehyde
resols or phenol novoalks, or, by adding styrene or dicyclopentadiene.
Limited compatibility may also be achieved by replacing part of the
starting hydrocarbon resin containing cyclopentadiene units used by a
conventional hydrocarbon resin from crude oil fractions.
In the following Examples which serve to illustrate the process according
to the invention % are by weight. The viscosity measurements in cP were,
unless otherwise stated, measured in 50% toluene solution at 20.degree. C.
The viscosity measurements in P were, unless otherwise stated, determined
at 20.degree. C. in 40% solutions in linseed oil and in two mineral oils
with a boiling range of (A) 280.degree. to 320.degree. C. and (B)
240.degree. to 270.degree. C. The mineral oil B is richer in aromatics
than mineral oil A. Moreover, the compatibility of the products with these
mineral oils was ascertained. The melting points given in the Examples are
in each case measured by the capillary method.
EXAMPLE 1
600g of colophony were mixed with 1200 g of a polymer prepared from
cyclopentadiene monomer (bromine number of polymer 125; melting point
75.degree. C.; viscosity 9.9 cP; fully compatible with petroleum ether
with a boiling range of 80.degree. to 110.degree. C.) and 1100 g of a
resol modified with styrene prepared from 1800 g of p-tert.-butylphenol,
737 g of formaldehyde and 150 g of styrene at an elevated temperature in a
4 liter flask with a water separator and reflux cooler. The mixture was
then heated for one hour at 200.degree. C. and for a further hour at
250.degree. C, the water formed being continuously removed and the solvent
being recycled in. The presence in the reaction vessel was reduced to 50
mmHg and the mixture was heated for a further hour at 250.degree. C.
Yield: 2479 g. Characteristics: melting point 169.degree. C.; acid number
30; viscosity in toluene 119 cP, in linseed oil 520 P, in mineral oil A
100 P, in mineral oil B 16 P; compatibility with both mineral oils: more
than 1.2. The resin is suitable for use as a fast drying binding agent for
offset roller printing.
EXAMPLE 2
300 g of colophony and 600 g of the hydrocarbon resin used in Example 1
were melted together and 300 g of p-tert.-butylphenol, 2 g of zinc acetate
and 130 g of paraformaldehyde were added. The mixture was heated under
reflux for 2 hours at 110.degree. C. The reflux cooler was then replaced
by a water separator. The mixture was heated for 1 hour at 200.degree. C.,
the water formed being continuously removed. 45 g of glycerol were added
and the mixture was heated at 250.degree. C., for 4 hours, and then for a
further hour at the same temperature under reduced pressure of 50 mmHg.
Yield: 1175 g. Characteristics: melting point 179.degree. C.; acid number
15; viscosity: in toluene 154 cP, in linseed oil 765 P, in mineral oil A
160 P, in mineral oil B 25 P; compatibility of the resin with both mineral
oils 1:2.
EXAMPLE 3
600 g of wood resin, 600 g of the hydrocarbon resin as in Example 1 and 600
g of p-tert.-butylphenol were melted together and 4 g of zinc acetate, 35
g of pentaerythritol and 196 g of paragformaldehyde were added. The
process was continued as in Example 2.
Yield 1179 g. Characteristics: melting point 165.degree. C.; acid number
42; viscosity: in toluene 150 cP, in linseed oil 422 P, in mineral oil A
135 P, in mineral oil B 20 P. The compatibility of the binding agent with
the two mineral oils were greater than 1:2.
EXAMPLE 4
600 g of tall oil resinic acid and 900 g of the hydrocarbon resin used in
Example 1 were melted together. 400 g of p-tert.-butyl-phenol, 4 g of zinc
carbonate and 196 g of paraformaldehyde were then added and the mixture
was heated under reflux for 4 hours. After replacement of the reflux
cooler by a water separator, the mixture was heated at 250.degree. C. for
2 hours, during which time 30 g of glycerol and 35 g of pentaerythritol
were added. After heating for 3 hours at 250.degree. C., the mixture was
kept for 1 hour at 260.degree. C. at a pressure of 50 mmHg.
Yield: 2105 g. Characteristics: melting point 168.degree. C.; acid number
22; viscosity: in toluene 125 cP, in linseed oil 300 P, in mineral oil A
20.5; compatibility with mineral oil A 1:2.5.
EXAMPLE 5
600 g of Portuguese colophony and 1200 g of the hydrocarbon resin used in
Example 1 were melted together. 600 g of p-tert.-butylphenol, 100 g of
xylene, 2 g of magnesium oxide and 260 g of paraformaldehyde were added
and the mixture was heated under reflux for 4 hours. The reflux cooler was
replaced by a water separator, and the mixture was first heated at
200.degree. C for 1 hour and then at 250.degree. C for 4 hours. It was
then kept for a further hour at this temperature reducing the pressure
down to 50 mmHg.
Yield: 2379 g. Characteristics: melting point 188.degree. C; acid number
30; viscosity; in toluene 222 cP; in linseed oil 1320 P, in mineral oil A
43 P; compatibility with mineral oil 1:2.8.
The resin according to Examples 2 to 5 are suitable as fast drying binding
agents for offset roller printing inks. If a hydrocarbon resin is used as
starting material which contains, in addition to cyclopentadiene and/or
its derivatives, 3% of styrene and 2% of vinyl toluene, there is obtained,
under otherwise identical conditions, a product with a rather lower
melting point but equally good printing properties.
EXAMPLE 6
A resin was prepared analogously to Example 5 except that, instead of
magnesium oxide, 4 g of zinc carbonate were used.
Yield 2349 g. Characteristics: melting point 178.degree. C.; acid number
30; viscosity: in toluene 185 cP, in linseed oil 1420 P, in mineral oil A
440 P, in mineral oil B 34.5 P; compatibility with both mineral oils
greater than 1:2.
The resin prepared above was diluted with 120 g of mineral oil A to yield a
product with a mineral oil content of 5%. It had the following
characteristics: melting point 148.degree. C.; acid number 29; viscosity:
in toluene 103 cP, in linseed oil 346 P, in mineral oil A 100 P, in
mineral oil B 15 P. The compatibility of this product with the two mineral
oils was greater than 1:5.
EXAMPLE 7
1000 g of the hydrocarbon resin used in Example 1, 50 g of Protuguese
colophony and 300 g of p-tert.-butylphenol were melted together, and 12 g
of calcium acetate and 150 g of xylene were added. After the addition of
100 g of paraformaldehyde, the mixture was heated under reflux for 4 hours
at 120.degree. C., and then at 250.degree. C. for 3 hours using a water
separator. The mixture was kept at this temperature for 3 hours at normal
pressure and then for a further hour reducing the pressure to 400 mmHg.
Yield: 1260 g. Characteristics: melting point 203.degree. C.; viscosity: in
toluene 167 cP, in linseed oil 1630 P in mineral oil A 96 P, in mineral
oil B 21.6 P; compatibility with the two mineral oils greater than 1:2.
EXAMPLE 8
A resin was prepared analogously to Example 7 but using 3 g of magnesium
oxide instead of 12 g of calcium acetate. A resin with similar good
properties for use as a fast-drying binding agent was obtained.
Yield: 1236 g. Characteristics: melting point 201.degree. C.; acid number
8; viscosity: in toluene 159 cP, in linseed oil 806 P, in mineral oil A
130 P, in mineral oil B 24.4 P; compatibility with the two mineral oils
greater than 1:2.
EXAMPLE 9
A resin was prepared analogously to Example 7 but using 13 g of zinc
acetate instead of 12 g of calcium acetate. A resin with similar good
properties for use as a fast-drying binding agent was obtained.
Yield: 1301 g. Characteristics: melting point 199.degree. C.; acid number
10; viscosity: in toluene 194 cP, in linseed oil 1130 P, in mineral oil A
179 P, in mineral oil B 22.7 P; compatibility with both mineral oils
greater than 1:2.
EXAMPLE 10
240 g of colophony and 480 g of the hydrocarbon resin used in Example 1
were melted together. 50 g of xylene, 100 g of nonylphenol, 28 g of
paraformaldehyde and 398 g of a resol prepared by base catalysed alkaline
condensation of 1800 g of p-tert.-butylphenol and 674 g of formaldehyde
(dry residue 71.5% for 1 hour/135.degree. C) are added. The mixture was
kept at 250.degree. C. for 3 hours the water formed being continuously
removed and then for a further hour at this temperature reducing the
pressure to 450 mmHg.
Yield: 1076 g. Characteristics: melting point 172.degree. C.; acid number
34; viscosity: in toluene 192 cP, in linseed oil 1030 P, in mineral oil A
183 P, in mineral oil B 40.7 P; compatibility with both mineral oils
greater than 1:3.
EXAMPLE 11
300 g of Chinese colophony and 600 g of a polymer from cyclopentadiene
monomer (bromine number 140; melting point 44.degree. C; viscosity 6.9 cP)
were melted together. 300 g of p-tert.-butylphenol, 50 g of xylene, 140 g
of paraformaldehyde and 2 g of zinc carbonate were added and the mixture
was heated under reflux for 4 hours, and then at 250.degree. C. with
continuous removal of the water formed. The mixture was kept at this
temperature for a further hour reducing the pressure to 50 mmHg.
Yield: 1179 g. Characteristics: melting point 170.degree. C.; acid number
34; viscosity: in toluene 160 cP, in linseed oil 869 P, in mineral oil A
592 P, in mineral oil B 61.5 P; compatibility with both mineral oils
greater than 1:2.
EXAMPLE 12
A resin was prepared analogously to Example 11 but using a hydrocarbon
resin with bromine number 136, melting point 59.degree. C. and viscosity
8.2 cP.
Yield: 1161 g. Characteristics: melting point 174.degree. C.; acid number
35; viscosity: in toluene 156 cP, in linseed oil 865 P, in mineral oil A
304 P, in mineral oil B 42 P; compatibility with both mineral oils greater
than 1:2.
EXAMPLE 13
600 g of colophony were added to 1200 g of a molten cyclopentadiene polymer
(melting point 129.degree. C., viscosity 28.6 cP). A water separator was
used when the temperature reached 180.degree. C. 215 g of xylene and
subsequently 975 g of a resol consisting of 1200 g of p-tert.-butylphenol,
880 g of nonylphenol and 719 g of formaldehyde (processing viscosity 2460
cP, dry residue 70.2%/1h/135.degree. C.) were added. The mixture was
heated to 250.degree. C., the water formed being continuously removed. The
temperature was then held at 250.degree. C., and the pressure was reduced
to 50 mmHg, the volatile components being thus distilled off.
Yield: 2426 g. Characteristics: melting point 177.degree. C.; acid number
32.5; viscosity: in toluene 550 cP, in linseed oil 6730 P, in mineral oil
A 1410 P, in mineral oil B 125 P; compatibility with both mineral oils
1:2. The resins prepared in Examples 10 to 13 are suitable as binding
agents for fast drying offset roller printing inks.
EXAMPLE 14
A resol was prepared from 1500 g of p-tert.-butylphenol, 440 g of
nonylphenol and 719 g of formaldehyde (dry residue 67.4%/1 h/135.degree.
C.), and was reacted with 600 g of colophony at 150.degree. C. while the
water formed was continuously removed. At 160.degree. C., 1200 g of the
hydrocarbon resin used in Example 1 and 50 g of xylene were added. The
mixture was heated at 250.degree. C. for 2 hours and then for a further 40
minutes at this temperature reducing the pressure to 50 mmHg.
Yield: 2378 g. Characteristics: melting point 188.degree. C.; acid number
25.7; viscosity: in toluene 321 cP, in linseed oil 1520 P, in mineral oil
A 435 P, in mineral oil B 51 P; compatibility with both mineral oils
greater than 1:2.
EXAMPLE 15
240 g of Portuguese colophony and 27 g of mineral oil A were heated to
200.degree. C. and 480 g of the hydrocarbon resin used in Example 1 were
added thereto. 410 g of a resol (dry residue 70%/1 h/135.degree. C.)
prepared by base catalysed condensation of 1800 g of p-tert.-butylphenol
and 710 g of formaldehyde were then added to the melt at 160/170.degree.
C. The mixture was finally heated at 250.degree. C. for 3 hours.
Yield: 1053 g. Characteristics: melting point 168.degree. C.; acid number
27; viscosity: in toluene 177 cP; in linseed oil 825 P, in mineral oil A
239 P; in mineral oil B 28.7 P; compatibility with both oils greater than
1:2.
The products of Examples 14 and 15 were suitable for use as binding agents
for fast drying offset roller printing inks.
EXAMPLE 16
100 g of Portuguese colophony and 500 g of the hydrocarbon resin used in
Example 1 were melted together. 400 g of resol prepared by alkaline
condensation of p-tert.-butylphenol and formaldehyde in a mol ratio of
1:1.3 (dry residue 63.7%/1 h/135.degree. C.) were added to the mixture at
180.degree. C. The mixture was heated to 250.degree. C., the water formed
being removed, and after 3 hours the volatile components were removed at
250.degree. C. under reducing pressure, until a pressure of 50 mmHg was
attained.
Yield 859 g. Characteristics: melting point 179.degree. C.; acid number
22.4; viscosity: in toluene 135 cP, in linseed oil 531 P, 45% solution in
mineral oil (boiling range 240.degree. to 270.degree. C., deodorised,
lower aromatics content than mineral oil A) 485 P; compatibility with this
mineral oil 1:3.
The product was suitable for use as a binding agent for offset roller
printing inks, or as a correcting resin for highly viscous binding agents
to lower the viscosity of printing varnishes prepared therefrom.
EXAMPLE 17
600 g of p-tert.-butylphenol, 600 g of colophony, 60 g of glycerol and 600
g of the hydrocarbon resin used in Example 1 were melted together and 4 g
of zinc carbonate were added. The mixture was condensed with 178 g of
paraformaldehyde by heating under reflux. The cooler was then removed and
the mixture was heated at 250.degree. C. for 4 hours. The pressure was
then allowed to fall to 50 mmHg, while holding the temperature at
250.degree. C.
Yield: 1832 g. Characteristics: melting point 174.degree. C.; acid number
30; viscosity: in toluene 169 cP, in linseed oil 650 P, in mineral oil A
(33.3%) 70.5 P; compatibility with mineral oil A 1:2.4; compatibility with
petroleum ether (boiling point 80/110.degree. C.) 1:3.9. The resin may be
used with good results as a binding agent for both offset roller printing
and for letterpress printing and offset block printing.
In the following printing ink tests, the suitability of the resins
according to the present invention as binding agents for offset roller
printing inks is compared with that of known binding agents. In particular
the drying speeds of the inks under the influence of heat were compared.
PREPARATION OF THE PRINTING INKS
Varnishes were prepared from 40% by weight of resin according to Examples 1
to 15 and 60% by weight of mineral 60% by weight of mineral oil, and were
adjusted either by further dilution with mineral oil or by using
correspondingly larger quantities of resin, to an overflow time of 260 to
300 seconds at 20.degree. C. in a 4 mm DIN cup. A quantity of each mixture
which contained 10g of solid resin was mixed with 1 g of linseed oil, 0.15
g of polyethylene wax, 1.825 g of a commercial organic dye
["Hostapermblau"(registered Trade Mark of Hoechst Aktiengesellschaft)B 3
G] and 0.125 g of driers (mixture of cobalt octoate and manganese
octoate). Offset roller printing inks were then prepared by passing the
mixture six times over a triple roller.
PRINTING TESTS
0.1 g of each of 4 printing inks was applied to a sheet of coated paper
weighing 120g/m.sup.2. The inks to be tested were applied at separations
of 15 mm with a 12 mm diameter steel rod. Immediately after the inks had
been applied to the paper base, the paper was suspended vertically in a
drying chamber heated with a blow torch to 150.degree. C. and was then
removed after 10 seconds. The paper was covered with a clean DIN A5 sheet
of the same paper and was weighted down with a pressure of 45 kg/cm.sup.2
above each strip of ink by means of a block testing apparatus developed by
(Epprecht). If the ink was completely dry, no imprint was left on the
upper sheet of paper and the test was designated the figure 0. If the ink
was still very tacky and therefore a large amount of ink was transferred
to the upper sheet of paper, the test was designated 5. Intermediate
stages of the drying process were accorded figures between 0 and 5, the
lower numbers indicating more complete drying. The test described was
performed in similar manner four times in all with each ink, each time the
drying time being increased by 5 seconds. Thus each ink was tested after
having been dried at 150.degree. C. for 10, 15, 20 and 25 seconds
respectively.
For comparison purposes, the same test was conducted with the following
three commercial resins used as binding agents for offset roller printing.
Control resin A is a phenol resin modified by natural resin.
Characteristics: melting point/capillary method 155.degree. C., acid
number 17, viscosity 150 cP.
Control resin B is a resin prepared from dimerised colophony by reacting
with phenol-formaldehyde condensation products and with .alpha.,
.beta.-unsaturated dicarboxylic acids and polyhydric alcohols.
Characteristics: melting point 164.degree. C., acid number 30, viscosity
190 cP.
Control resin C is a high-melting polymer resin from cyclopentadiene.
Characteristics: melting point 190.degree. C., acid number 0, viscosity 85
cP. The results of the tests are assembled in the following Table I which
lists
(1) the outflow viscosity of the varnish ink/mineral oil
(2) the quantity of each varnish having an outflow time in a 4 mm DIN cup
in the range 260-300 seconds, which contains 10g of solid resin, and
(3) the drying rates of the inks applied.
Addition of the four drying figures for each ink tested gives a total
figure which may be used to compare the drying properties of the inks. The
lower the total, the faster is the drying of the ink at 150.degree. C.
Table 1
__________________________________________________________________________
heat drying
quantity of varnish
of inks at total of
varnish outflow
containing 10 g
150.degree. C.
Columns
Example time in sec/20.degree.
solid resin
10"
15"
20"
25"
4-7
__________________________________________________________________________
INVENTION
1 300 25 5 2 1 0 8
2 303 25 5 2 1 0 8
3 290 27.9 3 1 0 0 4
4 280 27.2 3 1 0 0 4
5 308 26.1 3 1 0 0 4
6 288 26.7 4 2 0 0 6
7 288 25.99 5 2 2 0 9
8 300 25.3 4 1 0 0 5
9 280 25.5 5 1 0 0 6
10 302 26.3 5 2 2 0 9
11 300 26.3 4 4 0 0 8
12 284 26.0 4 0 0 0 4
13 304 28.6 5 1 0 0 6
14 300 26.7 5 2 0 0 7
15 270 26.5 3 1 1 0 5
COMPARISON
resin A 312 26.5 4 4 2 0 10
resin B 284 25 5 5 | | |
