Improvements in or relating to Flour and Starch Pastes, and Processes of Making the same.
Year: 1896

page_text: Date of Application, 6th June, 1896-Accepted, 11th July. 1896
COMPLETE SPECIFICATION.
Improvements in or relating to Flour and Starch Pastes, and
Processes of Making the same.
A communication from CHARLES M. HIGGINS, of Brooklyn, in the County of
Kings and State of New York, United States of America, Manufacturer.
I, ALFRED JULIUS BOULT of 111 Hatton Garden, in the County of Middlesex,
Chartered Patent Agent, do hereby declare the nature of this invention and in what
manner the same is to be performed, to be particularly described and ascertained
in and by the following statement :-
The object of this invention is to produce an improved paste or adhesive
compound directly from common flour or starch which shall possess much greater
adhesive power and tenacity and more homogeneity and durability than any
previous starch or flour paste, and which shall even be superior to pastes made
directly from dextrine and be producible at much less cost and with greater ease
and facility of manufacture.
In making this improved paste the flour or starch is digested directly in hot
water impregnated with a free acid or other digesting agent adapted to dissolve
the gluten and convert or digest the starch into a soluble or partly soluble form,
and the digestion is continued rapidly until the pasty mixture becomes partly or
fully liquefied at or about 190° F., and then the liquid solution is run into jars or
receptacles and allowed to cool and rest until the contained liquid assumes a pasty
form. Previous to running off the liquid solution a neutralizing substance is added
to neutralize the acid, preferring for this purpose borax in excess, or such
ingredients as will form borax in the solution for it is found that while borax
or boracic acid have no action on either raw or boiled starch, they enter into
chemical combination with it as soon as it acquires a soluble or partly soluble
form and render its solubility permanent and greatly add to the adhesiveness and
homogeneity of the resulting paste. This invention therefore cousists mainly in
the features above outlined as hereinafter fully set forth.
In making this improved paste or adhesive compound any of the ordinary cereal
flours made from wheat, rye, rice, corn, etc. or any of the starches from corn,
wheat, potatoes, etc., or any mixture of the same, each material producing
compounds or pastes or individually different qualities adapted for different
purposes as will be understood.
I will therefore now fully describe this novel process of paste manufacture, and will
first give a model formula which may be used with any of the flours or starches,
or with mixtures of the two, and which will epitomize the process and enable it to
be seen in a paragraph.
To one gallon of water add about one fluid ounce of commercial sulphuric acid
and six ounces (avoirdupois) of boric acid ;-Heat this acidulated water to
about 145° F. and add four pounds of the desired flour or starch. Mix
thoroughly and while the mixture is kept continually stirred or agitated continue
the heat and raise it rapidly to about 195° or thereabouts until the resulting pasty
mixture becomes partly or fully liquefied. Then stop the heat and add four to
five fluid ounces of caustic soda lye of 40° Baume which will neutralize both acids
in the solution and give it an alkaline reaction. After the foregoing have been
well mixed, finally add three fluid ounces of aqua ammonia of 20° Baume, which is

page_text: about of the volume of the solution, and mix intimately: then run the hot
neutralized solution directly into jars or other receptacles in which the product is
to be sold, and cool the same and let them rest until the contents assumé a soft or
firm pasty form, according to the consistency desired and the product will be then
ready for the market.
In the above process the acidulated- water should be heated preferably in a
jacketed steam kettle so constructed that a large quantity of heat can be applied
rapidly and steadily to the mass, as rapid and even action of the heat is important
in the process. This cooking kettle should also be provided with an energetic
stirrer or mixer kept in constant motion during the process, and this stirrer should
be very strong and powerful to move the thick pasty mass which is formed when
the temperature reaches 150° to 160°. The complete process described usually
takes from about twenty to forty minutes from the moment when the starch is
added to the time when the solution is neutralized and run off, and its phases are
about as follows; in about three minutes after adding the starch the mass stiffens
into a white dough at about 150°; in six minutes, at 155°, a stiff white jelly is
formed; in ten minutes, at 165°, this changes to a translucent jelly, and in about
fifteen minutes, at 170°, it becomes a soft translucent jelly gradually liquefying
In about twenty minutes this soft jelly becomes fluent at about 180°, and in about
five minutes more changes to a liquid jelly, opalescent in colour at about 185°.
In, say, thirty minutes the mass becomes a sirupy opalescent liquid at about 190°,
and from 1900 to 200°, within a total of thirty-five to forty minutes, the liquid
becomes a little thinner but is yet opalescent.
It will be noted that by heating the acidulated water as high as possible, but
below or about the temperature of the paste formation, and theu adding the dry
starch or flour directly thereto, and mixing vigorously while continued heat is
applied, that the operations of mixing and digesting are simplified and the process
rendered rapid, direct, and continuous, and active on the whole mass of starch at
once, which is important for this purpose. On the contrary if the starch were
separately mixed in a milky fluid with a portion of water which was then poured
into the main portion of highly heated acid water, as is usually done in making
glucose, the operation would be more indirect and troublesome, and consume much
more time, and the first part of the starch would receive more heat action than the
last and the starch would remain much longer under the converting action which
would cause it to pass completely over into the dextrine or glucose state which it is
important to avoid in this process. Instead, however, of first heating the acidulated
water to about 1450 and then adding the starch, the starch may he added to the
acidulated water when cold and the heat and agitation then applied continuously
until the process is completed as described.
Any other digesting substance or acid may be used in lieu of the sulphuric but
this is considered much preferable as less of it is required, and its action is much
quicker and its neutralization forms simple and harmless sulphates in the final
product which are in no way objectionable, for it will be noted that in this process
the products of neutralization remain in the finished product. If sulphurous acid
be used as the digester a sulphite will be left in the product which will act as an
antiseptic and be actually advantageous. Malt may be also used as the digesting
agent but with this the temperature has to be carefully kept at or below 165°, and
it is more likely to develop the sugar or glucose state immediately and to form a
thinner and darker product, and acids are therefore preferred as set forth.
The boracic acid while having no action on raw or boiled starch as before
stated, acts in the presence of the sulphuric acid to assist in the digesting action,
and what is still more important enters into chemical combination with the starch
as soon as it becomes changed to a soluble or partly soluble form, and holds it
in this state and renders its solubility permanent. When this boric acid is
subsequently neutralized by the caustic soda it becomes changed into borax which
makes still mure energetic combination with the digested starch and renders it
much more adhesive and tenacious, greatly increases the bly of the solution,

page_text: and renders it more smooth and homogeneous. This combination of the boron-
compound takes place only at a high temperature and not in the cold, that is
not below 90° or 100° F. The ammonia, or other caustic alkali, added after the
formation of the borax acts to produce a still further thickening effect and
further increases the adhesiveness of the compound and also renders it perfectly
proof to decay while the presence of the volatile alkali is not objectionably
apparent to the senses. This action of the ammonia, or other caustic alkali,.
however, will take place at a hot or cold temperature, but my correspondent
prefers to add it at about 150°.
Another effect of the boron compound in the presence of alkali is to
prevent the alkali from darkening the colour of the paste, for, if the boron
compound were omitted, great care would have to be used in adding the
nentralising alkali so that exact neutrality was reached as the slightest excess
of the caustic alkali would render the paste very brownish or yellowish, whereas
in the presence of the boron compound a small excess of alkali which is really
desirable has no effect on the colour, which in this case remains creamy in the
flour pastes and pure white in starch pastes, which is a most important advantage.
The proportion of ingredients may of course be altered where a thicker or
thinner paste or adhesive is required, as about the average proportion is given:
in the model formula. But the flour or starch may vary from say, three or less
to seven or more pounds to the gallon of water, two to seven being about the
extremes while four to five is the medium. The proportion of other ingredients
should vary to correspond with the starch or flour except the digesting acid,
which is preferably increased a little, but need not necessarily increase in pro-
portion to the increase of flour or starch, but should always increase where the
proportion of the water increases.
Where the amount of acid is reduced or the proportion of starch is increased
from that set forth in the model formula the time required to complete the
process will be longer than thirty or forty minutes, and may extend to sixty
minutes, more or less, according to the proportions of starch cad acid, as will be,
understood.
A greater proportion of acid may be used than that stated, but my correspondent
prefers to limit it to the lowest practicable, and it is desired to avoid the full
conversion of the starch into dextrine and glucose which is likely to happen if
much acid is used and if the heat and digesting action are continued long, or
if the temperature be very high. It is therefore preferred not only to have
the digesting action as direct and rapid as possible and uniformly on the whole
mass of starch at once as described, but to arrest this action just when actual
digestion takes place, that is, when the starch changes from the gelatinous to
the fluent form, but while it is still whitish or opalescent and before transparent
or clear, thin, fluidity occurs, which preferred condition will occur in this process
as described in from twenty to thirty minutes or thereabouts after the starch is
added, thus making the process as rapid and simple, if not more so, that the
common process of boiling a simple starch or flour paste.
Instead of adding boracic acid to the acidulated water, it may be omitted
altogether, but afterwards add borax to the digested solution in place of the
caustic soda which will then neutralize the digesting acid and combine with the
digested starch. In the formula given the correct proportion of borax would be
about fourteen ounces, a large excess over neutrality being desirable to combine
with the digested starch, and this should be added before the starch becomes fully
liquefied and while in the state of a soft fluent jelly at about 175° to 185°. When
added at this point the borax has the effect of thinning the solution and renders
the starch more soluble and combines with it to make it permanently soluble.
The borax may be added later, say, from 190° to 200°, but if added to late, say,
beyond 2000, it would be likely to reuder the product too thin or liquid as it
seems to exert an actual digesting action on the starch after this action has been,
started by the digesting acid. But, of course, where a very thin product is desired"

page_text: the heat can be continued and the borax added later. In the same way if the
heat and digesting action were continued too long, or much above 195° and much
over thirty or forty minutes unless the proportion of starch were very large or
of acid were very small, the starch would have passed over too much into the
state of veritable dextrine or glucose, and the product when finished would not be
a more or less fluent paste of great adhesive power and good body or viscosity,
but rather a thin liquid of diminished adhesive power which it is desirable to
avoid. Hence by conducting the process rapidly and uniformly and arresting the
digestion before the state of veritable dextríne is reached and at the point where
the starch becomes soluble, or partly so, and where it is capable of combining with
the boron compound, a very novel paste or adhesive compound of great value is
produced for it possesses far more adhesive power, more body and viscosity than,
is possessed by any paste that can be made from dextrines, for in this case it seems
that the starch simply loses its gelatinous insoluble form and acquires a state of
white glutinous viscid solubility which may be said to be a distinct state.
it is preferred to arrest the digestion as before stated at the point where the starch
ceases to be pasty or gelatinous and where it becomes fluent but before it has lost
its white or opalescent colour, while it still gives a blue, violet, or purple colour
with iodine, before it becomes transparent and thin and before it gives the decided
reddish or claret wine colour with the iodine.
By arresting the digesting action earlier or later, that is anywhere between the
point where the mixture becomes a fluent jelly to the point where it becomes
a thin liquid, different degrees of body or consistency can be imparted to the
finished product which is an important advantage of this process as will be
understood.
A firmer consistence can also be imparted to the finished product by a forcible
or continued cooling or refrigeration of the solution when run into the jars
on the principle set forth in my correspondent's U.S. Patent No. 546401 of
September 17, 1895. In the aforesaid patent the consistency of a dextrine paste
is regulated and determined by limiting the heat in making the solution and in
afterwards applying continued cold or refrigeration to the liquid when bottled or
sealed. But this will not be necessary in the present process unless the digestion
has been carried too far because by arresting the digestion at the desired point
when the solution is neutralised and run into the jars a simple rapid cooling will
usually set the paste into the desired consistency which is a further advantage of
this process.
In the U.S. Patent No. 466239 of December 29, 1891, is described and
claimed a combination of dextrine with a boron compound combined in hot aqueous
solution, with an alkali afterwards added thereto. It will be noted that this present
invention covers the boron compound united directly with starch while being
digested, or in a soluble state, or as it is approaching incipient or nascent dextrine,
which is a new discovery of great advantage as it enables an adhesive compound to
be produced directly from common flour or starch which is far superior to that
which can be produced from dextrine and at far less cost. Indeed so much is this
the fact that by this new process three or four pounds of starch to one gallon of
water may be made to produce a paste of greater body and adhesive power than
can be produced with five to six pounds of dextrine and at about one-thind the cost
thus producing most valuable results. In addition to this advantage of body,
adhesiveness and cost the pastes made by the new process are far superior in
appearance, in possessing a much lighter and purer colour, and are much more
uniform in quality, and their consistencies and other properties can be more
readily and uniformly regulated at will than is the case with pastes made from
dextrines.
A great variety of pastes or adhesive compounds can be produced by this system
adapted for almost all purposes, and at costs to suit all purposes from the lightest to
the strongest work by the use of different flours or starches or mixtures of them, and
of greater or less densities according to the proportions used, and as I have fully set

page_text: forth the process and the best conditions for the manufacture, and the best pro-
portions and variations, it will not be necessary to specifically describe each.
individually different product which might be produced. I will mention however,
that some most remarkable adhesives can be produced by this process which can be
readily substituted for glues and gelatines in many kinds of work. For example-
when from five to seven pounds of corn starch to the gallon of water is used in the
formula given, a glue like paste is produced which is almost equal to the best
animal glues and has the most extraordinary cementing power for fibrous and.
absorbent substances as it will unite wood to wood nearly as firmly as gelatine,
that is, the joint cannot be separated without breaking the wood at some point,.
and it will also unite leather to leather, or leather to wood, so that the leather will.
tear or laminate in attempting to separate the joints. This paste is of a pure creamy.
white, slightly translucent, and in general qualities it could be readily mistaken for
a solution of the best gelatine except that it has a much whiter and more opaque
colour and has about the same consistency and flowing qualities in the cool that a
strong solution of gelatine or isinglass has when hot, that is, it will spread with
great ease and smoothness, does not sink into absorbents, and adheres at once and.
with great tenacity to almost all substances and is so very glutinous and tenacious
that it will draw or spin out into ropy or silky threads when manipulated so much so
that it would be difficult to convince the ordinary observer that it was not a
remarkable white and fine glue instead of being purely a starch cement.
In the case of simple flour pastes made by this process not only is the cost no-
greater than in the usual process of making common flour pastes, but a flour paste
of most unique and superior qualities is produced. It will be noted that in this
process not only is the starch of the flour rendered soluble, but so also is the gluten
which becomes dissolved by the weak digesting acid at the outset, and also by
the borax and alkali afterwards added. Hence both ingredients of the flour,
representing in the case of wheat 67 and 33 per cents. respectively, become changed,
into a soluble tenacious form and united in perfect combination or solution in the
water of the paste, whereas in ordinary flour paste the 67 per cent. of starch is
always more or less iuert and separable. Hence this new flour paste is not only.
homogeneous and permanent, but has unusual body density and adhesive power,
is very smooth and spreads easily, does not show watery separation, and is.
practically proof to decay, and thus presents a great advance in the art of paste.
manufacture.
As the process herein described of making an adhesive paste from flour or starch,.
with or without the boron compound, is novel, my correspondent does not of course
limit himself to the inclusion of the borax or other boron compound and hence any
other suitable substance may be used in neutralizing the digesting acid, or this
substance may be sometimes omitted for purposes where a small trace of acid in,
the paste will not be objectionable.
Having now particularly described and ascertained the nature of the said inven-
tion as communicated to me by my foreign correspondent, and in what manner
the same is to be performed, I declare that what I claim is.-
1. The improved process of making a flour paste consisting in digesting the flour
in hot water impregnated with a digesting substance until the gluten is dissolved:
and the starch rendered soluble, or partly so, and the mass thereby liquefied, then
arresting the digesting action and cooling the liquefied mass and allowing it
to rest till it sets into a semi-fluid or pasty form, substantially, as herein set
forth.
2. The improved process of making a starch or flour paste consist in dissolving
the flour or starch directly in hot water impregnated with a digesting substance,.
arresting the digesting action when the mixture becomes fluent but before it.
becomes converted into dextrine and while still in a white or opalescent soluble
starchy state & then running said opalescent liquid into jars or receptacles and

page_text: allowing the same to cool and rest until set into a semi-fluid or pasty form,
substantially as herein set forth.
3. The process described of making a starch or flour paste consisting in heating
a mixture of starch or flour with water impregnated with a digesting acid rapidly
to or about 190°, arresting the heat and digesting action when the mixture becomes
liquefied, but while still in a white or opalescent state, adding a neutralising
substance to the solution, and allowing the same to cool and rest until set into a
semi-liquid or pasty form, substantially as herein set forth.
4. The process of making an improved starch or flour paste in the manner and
proportions described, viz., adding to a given mass of water about one half of
one per cent. of digesting acid and a mass of starch or flour equal to half, or more,
of the weight of the water, keeping the mass constantly agitated and applying heat
to the whole mass uniformly at once for about thirty minutes till it reaches 190° or
thereabouts, and becomes an opalescent liquid, and finally cooling the said liquid,
substantially as and for the purpose herein set forth.
5. The improved process of making a starch or flour paste herein described
consisting in digesting starch or flour in hot water impregnated with a digesting
substance till it becomes soluble and liquefied and finally running the liquid into
jars or receptacles, and applying continued cold or refrigeration to the same until
the liquid contents are set into a pasty form, substantially as herein set forth.
6. The improved process of making a starch or flour paste consisting in digesting
the starch or flour in hot water impregnated with a digesting acid till it becomes
soluble and liquefied, then adding to the acid solution an alkaline sodium compound
in excess to neutralize the acid and give the solution an alkaline reaction, and then
cooling the solution until set into a semi-liquid or pasty form, substantially as
herein set forth.
7. An improved adhesive compound made from starch, water, and a digesting
agent heated together until the mixture becomes fluid and the starch becomes
soluble or partly so but not converted into dextrine, and having the digestion
arrested and the liquid cooled at this point, substantially as and for the purpose
set forth.
8. An improved adhesive compound made from starch, water, and a digesting
acid heated together until the mixture becomes fluid and the starch becomes
soluble, but not converted into dextrine, having the digestion arrested and the
liquid cooled at this point, and having an alkaline neutralising substance incorporated
in the solution, substantially as herein set forth.
9. An improved adhesive compound composed of starch converted into a soluble
form but still white or opalescent and before it reaches the state of actual dextrine
and then combined at a hot temperature with water and a boron compound,
substantially as herein set forth.
10. An improved adhesive compound composed of starch converted into a soluble
state but before reaching the state of actual dextrine combined at a hot temperature
with water and a boron compound with a caustic alkali afterwards added thereto,
substantially as berein set forth.
11. An improved adhesive compound formed of starch, hot water and a con-
verting substance and combined with borax or boracic acid, substantially as herein
set forth.
12. An improved adhesive compound formed of starch, hot water, and a con-
verting substance combined with a boron compound and an alkali, substantially as
herein set forth.
13. The improved adhesive paste or compound formed by heating a mixture of
starch and water with a converting acid in the presence of dissolved boracic acid
until liquefied and then adding caustic soda to neutralize both acids and form borax
in said solution, substantially as set forth.
14. The specific process therein described for making an improved paste directly
from starch or flour, viz. mixing the dry starch or flour with acidulated water at a

page_text: temperature below or about the paste formation and keeping the mixture constantly
agitated while the heat is applied, continuing the heat and agitation till the pasty
mixture becomes liquid and attains a temperature of 190° F., or thereabouts,
adding a neutralizing substance to the solution, discontinuing the heat and running
the hot neutralised solution into jars or packages and causing the same to cool and
rest until the liquid assumes a semi-liquid or pasty form, substantially as herein
set forth.
15. An improved adhesive compound, the product of the process herein described
having the qualities set forth, substantially as herein specified.
Dated this 6th day of June 1896.
BOULT & WADE,
Agents for the Applicant.