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Printing
lacquer for textiles:
A highly flexible
composition of good covering power suitable for roll printing
on fabrics, that will not "crock" or "dry mark off" is
prepared of the following composition.
| Toluidine toner |
4.75 parts |
| 1/2 sec nitrocellulose |
3.25 parts |
| Dibutyl phthalate |
5.5 parts |
| 5 sec.ethyl cellulose (Ethoxy content
less than 44 %) |
4.0 parts |
| Paraplex rg2 |
8.75 parts |
| Montan wax |
0.5 parts |
| Shellac solution (6 lbs.cut) |
4.5 parts |
| Butyl acetate |
12.25 parts |
| Toluol |
43.5 parts |
| Ethyl alcohol |
1.5 parts |
| Petroleum naphtha |
2.5 parts |
| Ethyl acetate |
9.0 parts |
The first three ingredients are dispersed
in a banbury mixer and thereafter admixed with the rest. The
finished composition has a viscosity of about 300 centipoises.
Paraplex rg2 is a resinous esterification product of
straight chain dibasic acids such as adipic, sebacic etc and
polyhydric alcohols such as glycerol, glycol and the like.
White ink for shellaced kymograph trackings:
Shellac varnish pigmented with titanium dioxide is
very satisfactory as a white ink for use on shellacked
kymograph paper.
Ink for printing on plastics:
A thermoplastic ink for printing on very thin aluminum
or other non fibrous non-theroplastic bases ("carriers") for
later transfer on to plastics has the following composition.
| Dewaxed bleached shellac |
75 parts |
| Nitrocellulose |
25 parts |
The two are dissolved in alcohol to which
a colouring matter id added.
This ink is used to
produce a negative (of the final print required) on the
carrier. When this is to be transferred to a thermoplastic
moulding, it can be done any time when the article is moulded,
as the negative will easily get transferred to the hot
thermoplastic surface, leaving the non thermoplastic carrier.
If the transfer has to be on to a thermosetting plastic, the
moulding of the latter has to be interrupted before the article
is fully cured. While the article is still hot, soft and
tacky, the mould will have to be opened and the print free carrier removed from the moulded article. Alternatively, the
carrier with the print may be placed in the proper place
inside the mould itself and the moulding and transferring
effected in one operation.
Transfer ink:
A solid transfer ink which can be printed in the fused
state on paper which can be transferred, under mild or strong
heat to other surfaces like leather, rubber, silk, cotton
fabrics etc is prepared on the following composition.
| Dewaxed bleached shellac |
5.00 parts |
| Titanium dioxide |
1.000 parts |
| Tricresyl phosphate |
0.50 parts |
| Rosin |
5.00 parts |
| Heavy grade lithographic varnish |
0.50 parts |
The shellac and titanium dioxide are mixed
together and heated and kept in the molten state till the lac
polymerises. The tricresylphosphate is then added and stirred,
followed by the addition of the rosin and the varnish. The
desired colouring matter such as bronze powders, dyes or
pigments are then added and intimately mixed. The mett is then
allowed to cool and solidify.
Printing of this ink on
paper may be transferred to other surfaces with the help of a
hot iron.
Printing compounds for transfer
printing:
Printing compounds especially suitable
for the printing, in high speed presses, of transfer patterns
from which the printed design is to be transferred on to
another surface like textile fabric etc. By moisture or by heat
and moisture are prepared as follows:
| Pure basic dye |
0.50 lb |
| Acetin |
2.00 lb |
| Dewaxed bleached shellac |
1.00 lb |
The shellac is stirred in the cold in the
acetin and the mixture gradually heated to about 340ºF
(171ºC).
When the shellac has melted, the dye is added. For darker
shades, the mixture is maintained at this temperature till all
the dye has melted and got thoroughly mixed in. For light
shades, the temperature may be reduced to 270ºF(132ºC) before
the dye is added.
Methylene yellow, rhodamine, crystal
violet, victoria blue, brilliant green and nigrosine are some
of the dyes that can be used. Water thinned printing inks:
A non inflammable vehicle for printing inks suitable
for use on rotogravure high speed presses is prepared from any
of the following three compositions
| |
I |
II |
III |
| Dewaxed bleached shellac |
10.00 |
10.50 |
15.00 |
| Powdered borax |
5.00 |
6.25 |
7.50 |
| Water |
85.00 |
81.25 |
77.50 |
The ingredients are heated together in a
steam jacketed kettle or other suitable receptacle till a
white foam appears on the surface. This is then allowed to
cool and filtered. The composition should then mixed with
emulsified oil prepared as below.
| Cotton seed oil |
40 parts |
| Powdered acacia |
10 parts |
| Water |
50 parts |
The oil is triturated with the acacia. 4o
parts of the water are then added and triturated followed by
the addition of the remaining water. Pigments may then be
incorporated.
Drawing, line and Indian inks:
Drawing, line and Indian inks are prepared from
dewaxed bleached shellac aqueous solutions using borax. The
pigments are milled in cold water and the dispersion mixed
with the shellac solution.
Water proof drawing
inks:
Water proof drawing inks are based on
shellac solution in water containing ammonia and borax and
synthetic dyes. Composition of the former and typical types
suitable are given below:
| Dewaxed bleached shellac |
50 gram |
| Ammonia (0.90) |
90 ml |
| Water |
360 ml |
| Phenol |
1 gm |
| Borax |
3 gm |
The lac is dissolved in the water
containing the ammonia with gentle heating after which the
remaining ingredients are incorporated. 50 ml of the cooled
solution is then mixed with 50 ml of dye solution containing
any of the following dyes in concentrations shown against
each.
|
For colour |
Dye |
Qty in 50 ml of solution for 100 ml of the ink) |
| Red |
Erythrosine yellowish |
0.50 ml |
| Orange |
Brilliant orange r |
0.60 ml |
| Yellow |
Chloramine milling green b |
0.40 ml |
| Green |
Brilliant milling green b |
1.20 ml |
| Blue |
Wool blue g extra |
0.50 ml |
| Violet |
Methylk violet b |
0.50 ml |
| Brown |
Benzamine brown 3 go |
0.80 ml |
The following dyes may also be used but
the water resistance of the ink will be somewhat inferior.
| Red |
Benzor fast orange s |
0.8 ml |
| Red |
Benzo fast orange s |
0.3 ml |
| |
Brilliant groceine m |
0.3 ml |
| Orange |
Orange r |
0.4 ml |
| Yellow |
Thiazol yellow |
0.8 ml |
| Yellow |
Metanil yellow |
0.8 ml |
| Blue |
New methylene blue n |
0.4 ml |
| Violet |
Crystal violet |
0.4 ml |
| Brown |
Benzo brown g |
0.6 ml |
Fluorescent Ink:
A
fluorescent bright red colouring material (specifically an
ink) is prepared of the following composition
| Dewaxed bleached shellac solution |
250 parts |
| Lithopone mixture |
200 parts |
| Xylene red |
2 parts |
| Quinoline yellow |
3 parts |
| Water |
150 parts |
The shellac solution for the above is
prepared by dissolving 100 parts of dewaxed bleached shellac
in 250 parts of water and 50 parts of borax with the aid of
heat. The lithopone mixture is made by grinding 50 parts
lithopone and 1.5 parts of a dispersing agent ( a salt of a
polymerised sulphonic acid resin) with 60 parts of water in a
ball mill.
Marking Ink for Mica:
A
water resistant mar proof marking ink for use on mica flakes
has the following compositions
|
A |
| Dewaxed bleached lac |
20 gm |
| Spirit |
100 ml |
|
B |
| Dewaxed bleached lac |
20 gm |
| Water |
100 ml |
| Ammonia (0.88) |
25 ml |
Dye (ammonia resistant)
Equal
proportions of A and B are mixed together and then the dye
incorporated.
Ink for making relievo-formes for
printing:
An ink that will swell on heating and
will trius be suitable for producing relievo formes for
printing purposes is produced of the following composition.
| Gum arabic (dry) |
9 parts |
| Commercial water glass |
1 parts |
| Autographic ink |
1 parts |
| Shellac (5%) solution in spirit |
1 parts |
| Venetian soap (dry) |
1 parts |
Colouring matter—water soluble-small
quantity.
Solventless:
Embossing powders:
Dewaxed bleached shellac ground to suitable mesh, in
conjunction with an appropriate pigment is used as an
embossing powder.
Raised or thermographic
printing:- special ink for.
The only resin which
will not crack or peel off from raised printings is shellac.
Special inks that improve the performance of shellac in this
field and usable for raised printing on glass, metal and other
non absorbent surfaces are made of the following compositions.
I
| Paracoumarone resin |
100 parts |
| Dibutyl phthalate |
100 parts |
| Cobalt linoleate or acetate |
2.5 parts |
50% of the dibutyl phthalate may be
replaced by an equal amount of butyl stearate. The shellac
powder may be "set" in the printed ink in 100-150 c. When
elastic characters in rounded relief will be obtained.
II
| Boiled Linseed Oil |
73 parts |
| Rosin |
8" |
| Carbon Black |
12" |
| Prussian Blue |
6" |
III
| Glycerine |
1.50 parts |
| Dextrin |
1.00" |
| Anilin Colour |
0.25" |
The amount of glycerin may be varied to
suit the weather conditions.
Dull raised
printing:
In raised printing or thermography,
shellac gives glossed raised rounded prints. If a dull finish
for the raised prints is desired, zinc stearate to the extent
of 6 per cent on the weight of shellac may be incorporated.
The shellac (100 parts) and zinc stearate (6 parts) may be
ground separately to the appropriate mesh, mixed and gently
warmed so that the stearate sticks to the shellac particles
but the mixture does not fuse. Alternatively, the shellac may
be fused with double the quantity, i.e. 12% of zinc stearate
and the fused mass ground to the appropriate mesh.
Aluminium plamitate or megnesia may also be used to
the same extent in place of zinc stearate for the same
purpose.
Moisture or steam set printing inks:
Solutions of shellac in poly hydric alcohols from
excellent vehicles for the formulation of moisture set
printing inks. These inks are stable in press room humidity
and are also fat and grease proof. The following are typical
compositions.
A)Vehicle
| Dewaxed Bleached Shellac |
40 parts |
| Polypropylene Glycol (Boiling Range 230-300ºC) |
60 parts |
B) Inks
| Colour |
Vehicle (a above) by weight |
Pigment |
Parts by Weight |
| Red |
76 |
Lithol Red Toner |
24 |
| Yellow |
40 |
Chrome yellow |
60 |
| Black |
80 |
Carbon black |
20 |
Other water insoluble pigments or dyes may
also be used in appropriate quantities.
| Diethylene glycol |
50 parts |
| "teglac" 127 and /or petrix acid |
40 parts |
| Dewaxed Bleached Shellac |
10 parts |
Teglar 127 is rosin modified by an
unsaturated poly-basic acid. Petrex acid is a terpene
hydrocarbon of the formula c10h16 modified by an unsaturated
polybasic acid.
Iii.press stable, moisture sensitive
printing inks can also be made from vehicles obtained by
dissolving shellac in a liquid polyhydric alcohol and adding
to the solution certain nitrogen containing compounds such as
amides, imides, amines, ammonia or ammonium salts. These inks
are stable to small amounts of water but insoluble in an
unlimited amount of water. typical compositions are indicated
in table 1.
The shellac, polyhydric alcohol and
nitrogenous compound are heated together at the temperature
indicated in column v a till a homogeneous melt is obtained.
Column v b indicates the approximate time taken to reach this
stage. Where this is left blank, this stage is reached by the
time the temperature indicated is reached. In the case of
ammonia (composition 13), the gas is passed through a warm
solution of the shellac in the glycol. The product is then
allowed to cool and forms the vehicle.
For preparing
the inks, these vehicles are milled with the pigments
indicated in column vi c and vi d together with the additional
solvents wherever necessary as indicated in column vi a and
vi b. Needless to say that the pigments are interchangeable.
Appropriate quantities of other desired pigments may also be
used.
Prints from these inks can be heat set or steam
set. The inks may also be used for printing on moist paper
which may then be set by heat.
Printing inks with high
humidity tolerance, capable of being set by steam and useful
for typographic printing with fast or slow operating presses
can also be prepared by esterifying shellac with dicarboxylic
acids or their anhydrides, in the presence or absence of
mutual solvents, and dissolving/di dissolving/dispersing the
product in a polyhydroxy alihatic alcohol. In table 2 shown
typical compositions.
The
shellac and the acid or anhydride are finely powdered and
intimately mixed together, with or without the mutual solvent
(column iii), and heated to the temperature indicated in
column v a and maintained for the period indicated in column v
b. The polyhydric alcohol indicated in column vi is then
gradually added and the product maintained at the temperature
indicated in column vii till dissolved. When a volatile
solvent is used, the heating has to be conducted under a
reflux condenser.
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