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Патент USA US2256253

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Patented
2,256,253
16, 1941
UNITED STATES PATENT ’ OFFICE
2,256,253 _
PRODUCTION OF PROTEIN-CONTAINING
UBEA-FORMALDEHYDE PLASTICS
Oscar Neuss, Berlin-Charlottenburg, Germany
No Drawing. Application April 6, 1938, Serial No.
200,422. In Germany August 11, 1933
10 Claims.
'
(Cl- 260-6)
the 'same poor homogeneity as the previously
described products since the albumen material
is only admixed in the urea condensation prod
ucts instead of being distributed in the course
The object of the invention is a process for
the production of albuminoid-containingplastic
masses from urea or its, derivatives and formal
dehyde as well as products obtained according
to this process. An important feature of the 5 of the condensation. The albumen material thus
invention consists in the fact that there is ob- . behaves in the pressed product as sand behaves
in concrete and the result of such non-homoge
tained by a relatively simple process, hardenable
neous masses is non-uniform swelling by the
masses which can be formed by pressing, the
action of moisture and unattractive surfaces.
pressed bodies obtained as products in this .way
having great homogeneity, good properties as 10 Further the pressed bodies are brittle and crack
on boring. Finally, it has also been proposed,
regards machinability, considerable elasticity,
in order to secure better removal of water from
permanence and resistance against atmospheric
the reaction mixture of-urea and formaldehyde I
influences and water.
with heating, to admix therewith or to knead
It is known to impregnate natural horn meal
v15
dehyde and to dry, mill and to press the same.
These condensates have been producedIin neu
tral media or in the presence of ‘saturated am
monia solutions. The horn meal, however, is in
part'attacked by the additions of alkalis and a 20
with urea or thiourea or both and with formal
partial break-down of the keratin results. The
hot water.
3
‘
_
It is also known to mix horn meal with a re
action product of urea and formaldehyde in
molten condition. In this case, however,v the
horn meal is non-plastic by reason of the heat
albumen containing materials, casein or wheat
gluten. When in such a process horn meal is
employed as the carrier material there arises
as a result of the hardening of the horn albu
men by heat and the formaldehyde, a non-plas
tic horn material which cannot be used in a
subsequent moulding operation. This action of
formaldehyde upon albumen, in particular kera
products so obtained show coloration and poor
characteristics in particular after contact with
therewith a swelling carrier material such as
tin,‘ as a coagulating and hardening agent is
25 known. Pressed bodies of horn meal for exam
ple can by treatment in formaldehyde be sub- a
sequently hardened. The formaldehyde forms
an outer hard surface on the keratin, which how-‘
ever hinders deeper penetration into the inner
and the considerable formaldehyde liberation
.
caused thereby and the products obtained from a0 parts of the pressed bodies.
Also the use of formaldehyde-binding sub
stances as additions to urea horn meal condensa
tion products does not, as has been described
In‘ order to avoid these dif?culties, horn meal
above, give satisfactory results, since these are
has been added to aminoplast subsequently as
filling material in the completed urea condensa 35 only stable in weakly alkaline media, but in acid
solution, however, formaldehyde splits oil.’ and
tion. The subsequent admixture of horn meal
keratin must be moulded in acid medium. The
with aminoplast products however, does not lead
pressing of horn in alkaline medium leads to a
to suf?oiently homogeneous bodies. The horn
darkening of the pressed bodies and renders them
meal remains as an extraneous body in the
aminoplast and homogeneity is lacking which is 40 of less value due to the attack upon the albumen
of the keratin by alkalis;
,
very undesirable when for example such ?nished
It has now been found that all these disad
pressed bodies come into contact with water.
vantages, in particular also the attack of the
The individual particles swell in differing degrees
alkali upon the albumen substances of the horn
and the object is unutilisable. It is similarly
the case in further known processes according 45 meal and the decomposition of the keratin occa-.
sioned thereby, can be avoided and press masses
to which the albumen material is pressed to
and pressed bodies of great homogeneity and
gether in the hot with urea formaldehyde con
these masses crack on boring and mechanical P
working and have a poor appearance.
a
good properties can be obtained if the manufac
densation products such as methylol derivatives
ture .of protein- or albuminold-containing' plas
of urethane, methylolurea or methylolamides
which only in the hot pressing process split of! 50 tic masses from formaldehyde and urea com
pounds is carried out in such manner that the
formaldehyde and thereby eil‘ect hardening.
This process is always difficult since the urea
formaldehyde condensate added to the albumen
material must previously-be made as such and
urea compounds and a greater than equimolecu- ‘ '
lar proportion of formaldehyde are allowed ,to
react upon each other in an aqueous ammoniacal
isolated. Further ~the finished products show 55 solution reacting weakly alkaline toward litmus,
2 -,
2,256,253
without external heating (pm-condensation),
and thereafter the mixture made weakly acid
toward litmus (the reaction product being still
in the water-soluble state) and treated with the
protein or albuminous material, whereupon the
condensation mixture is dried and pressed hot
at temperatures above 100° C. For, in the ?eld
of urea formaldehyde systems there exist partic-i ._
ular compounds that is to say condensates, which
fundamentally the horn meal is thoroughly
soaked through and after attaining the necessary
degree of dryness is pressed; Instead of the addi
tion of acid also a weakly acid horn meal that
is to say horn meal bleached with S0: can be
used. The faintly acid character of a horn meal
bleached with $02 su?ices in some circumstances
to give to the labile ammoniacal resin condensate
a quite weakly'acid character without causing,
can be mixed with keratin even in weakly acid 10 by a‘ too acid reaction, a precipitation and
solutions without any noticeable proportions of, hardening of the mass. - The keratin does not
free formaldehyde acting in a coagulating man
‘coagulate prior to the pressing and the material
ner upon the pressed material but which, how
can be readily formed into cakes and shows a
ever, in the subsequent hot pressing process on
considerable plasticity in the hot pressing
the one hand lead to resin formation and on the
process. The hardening of the pressed goods is
other hand to the splitting-off of formaldehyde
and therewith hardening of the keratin, albumen.
Primarily acid or neutral urea-formaldehyde
splitting o? ofvformaldehyde by the high tem
perature and simultaneously the high pressure
condensates are excluded in this connection as
utilised.
effected in the pressing process by the partial
these, even at ordinary pressure and temperature 20
conditions, split o? formaldehyde and unfavour
ably influence the albumen by prematurely hard- .
.
Instead of urea also urea derivatives, for ex
ample, thiourea or mixtures of - urea with urea
derivatives can be employed. Also other al
bumens can be used‘ which,-as in the case of
ening it.‘ Further, such urea-formaldehyde mix
tures separate out solid precipitates of conden
keratin, must be protected from the premature
sates in a short time. On the other hand, suit 25 action of free formaldehyde prior to the pressing.
able ammoniacal condensates practically do not
In the present process it is thus not a question
show this precipitationv even after addition of
of a known mixing. process in which. all possible
acid or, if they do, only after a disproportionally
substances, among which keratin and albumens
long period of action since they bind the free
can also be included, can be distributed as ?ll
formaldehyde and even after subsequent weak 30 ing materials in the aminoplast material or in
acidi?cation, and this is the decisive point, even
which inverted aminoplasts are admixed with
with mineral acid in the cold, no precipitate re
such press material. Rather it is a question of
sults. Accordingly it is thus possible for the
a condensation or hardening process of the
production of binding and hardening materials
aminoplast combined with a hardening process
for keratin to commence with a weakly ammo
niacal urea-formaldehyde condensation mixture
35 for the keratin, that is to say an improvement
of the properties thereof by the exchange action
of particular suitable labile acid, bodies of the
formaldehyde urea condensation system upon
the albumen material to be bound, and thus par
the horn meal in the pressing process itself. In
ticularly the horn meal, is intimately admixed 40 the same way the present process has nothing to
.or steeped with acidi?cation, is then dried and
do with. the known proposal to dissolve casein
if desired milled and the ?nal binding of the
in urea with or without additions of alkali then
constituents is then effected only by the conclu
to pour in free formaldehyde and by subsequent sion, in the hot pressing, of the previously in
strong acid precipitation of the solution to obtain
' completely e?ected condensation of the pressed
the solid condition. The disadvantages of this
material in faintly acid condition. The main .45 method of operation are threefold, namely, the
tenance of the molecular proportion on the one
destruction of the albumen by the attack of
hand and the hydroxyl and hydrogen ion con
alkalis in the solution, the addition of free forms
centrations on the other hand is always of de
aldehyde whereby coagulation of the albumen
cisive signi?cance as regards the labile charac
cannot be avoided and ?nally the use of a solu
50
ter of the condensate to be employed for the
tion which is not labile and which is caused to
hardening.
~
precipitate by addition of acid. In this solidi?ca
In the initially ammoniacal mixtures, for ex-, tion further free formaldehyde is split off which
ample, one molecule of urea is dissolved in about
can react in a coagulating manner upon the al
1.2 molecules of formaldehyde in aqueous solu
bumen even before the hot pressing. According
tion. Free formaldehyde is rendered non
to' the process of the present invention, on the
which for each molecule of urea contains more
than one molecule of formaldehyde. With this '
deleterious by ammonia, that is to say, is only _ other hand, the albumen is in no case dissolved.
so far neutralized that the solutionris faintly
By the solution of horn in urea (possibly under
alkaline and the free formaldehyde is‘ rendered
pressure,_with alkalis etc.) a breakdown of the
inactive by the ammonia. Hexamethylenetetra
keratin
occurs which results in considerable de
mine is therefore not suitable. An unnecessary 60 terioration in the water resistance of the ?nished,
excess of ammonia is not recommended since in
pressed objects. Such pressed objects acquire
the pressing operation the amines developed
blemishes even by the action of cold water for
thereby. unsatisfactorily in?uence the keratin. I a long time. In boiling water the surface there
The solutions after standing in the cold for some
of becomes rough to wholly deformed. It is thus
days should no longer smell or taste of formal
important in the present process that on the one
hand the albumen prior to coagulation is to a
for .use since the horn meal on pressing in.
far reaching extent‘ protected from free formal
. alkaline medium subsequently darkens, becomes I
dehyde and on the other hand from the attack
brown, and suffers considerably from the action
of free alkaline components (urea and ammonia)
of the alkali under heat and pressure. .The con 70 of the labile condensation solution by acidi?ca-‘
,densate must therefore be slightly acidi?ed.
tion. Finally the solution must be so labilethat
Even the slight acidi?cation in. the cold should
a mild acidi?cation under usual conditions can
not give any precipitate. - With such a solution
bring about no solidi?cation of the aminoplast
the. horn meal‘is mixed in such proportion that 75 condensate, the polymerisation and hardening
dehyde. , Such a solution is however not suitable
3
2,256,253
process taking place exclusively in the hot press
product dried and, if desired after milling, sub
itself.
jected to the hot pressing.
.
.
I
Example 5.--50 grs. of urea and 10 grs. of
thiourea are dissolved in 150 grs. of 40% formal
dehyde and then neutralised with ammonia un
til the solution reacts faintly alkaline towards
litmus. The solution is allowed to stand for
Prior to or during the condensation, ?lling
materials, plasticising materials, colouring mate
rials and other additions can be introduced into
the reaction mass. .Also certain proportions of .
phenols can be employed as components of the
condensation. The horn meal can ?rst be swollen
in water and then added to the components of
3 hours. Then 160 grs. of this solution which is
faintly acidi?ed with phosphoric acid is mixed
the aminoplast. It is possible, however, also 10 with 25 grs. of gelatine, the product dried and
then, if desired after milling, subjected to the
to proceed by allowing the-horn meal to swell
in the solution of urea and then ‘adding the form
hot pressing.
aldehyde. The working up to the dried products
Example 6.—50 grs. of urea and 10 grs.
thiourea are dissolved in 150 grs. of 40% formal
is effected in the usual manner. From the mass
'
obtained after drying, ?nished products can be 15 dehyde and then neutralised with ammonia un
til the solution reacts faintly alkaline towards
obtained in a single operation by hot pressing. litmus. The solution is allowed to stand for 3
It is also possible, however, to proceed by ?rst
hours. 160 grs. of this solution which is faintly
pressing or forming into cakes at ordinary or
acidi?ed with phosphoric acid is mixed with 50
moderate temperature so as not to cause thermo
setting, followed by a ?nal pressing in the hot 20 grs. of commercial defatted casein powder, the
press.
product dried and, if desired after milling, sub- '
The process can be conducted with or
jected to the hot pressing.
As already indicated hereinabove, there may
be employed in my improved process urea itself
without the presence of ?lling materials.
In the following, a number of examples are
given by way of illustration. In the, hot press
the press material resulting can be formed into 25 and thiourea, as well as other urea derivatives
whose condensation reaction with formaldehyde
is substantially equivalent to that of urea and
all kinds of objects, for example knobs, umbrella
handles or the like.
'
'
Example 1.—60 grs. of urea are dissolved in‘ ’
thiourea.
.
-
.
120 grs. of 30% aqueous formaldehyde solution.
I claim:
It is then neutralised with ammonia until the 30
1. Process for the manufacture of plasti
solution shows a faint alkalinity towards litmus.
The solution is allowed to'stand for 3 hours.
150 grs. of the solution are then mixed with 50‘
grs. of horn meal which has been treated with
4
~
masses from a urea and formaldehyde and con
taining protein material, comprising causing a.
urea and a molecular excess of formaldehyde to
‘ react upon each other without external heating
sulphurous acid, and the paste dried carefully 35 in an aqueous ammoniacal solution which is
weakly alkaline towardlitmus, acidifying the re
in the air or at moderate temperatures, the dried
action mixture until it is weakly acid toward
product, if desired after milling, being subjected
litmus, mixing the same with a protein material,
to hot pressing at temperatures above 100° C.,
and thereafter drying the reaction mixture.
preferably at 130° C. If desired, the ground
2. Process according to claim 1, wherein the
product can ?rst be subjected to a slight pressure 40
protein component is. horn meal.
at relatively low temperature to form it into 2
3. Process according to claim 1, wherein the
coherent, but not yet hardened cake, after which
it may be shaped and hot-pressed as stated, the
?nal condensation taking place during such hot
pressing.
'
protein component is horn meal which has been -
caused to swell in water prior to mixing with
45 the other reaction components.
4. Process according to claim 1, wherein the
Example 2.—-60 grs. of urea are dissolved in
reaction under acid conditions is conducted with
150 grs. of 40% aqueous formaldehyde solution
cooling of the reaction'mass.
and then neutralised with ammonia until the
5. Process according to claim 1, wherein the
solution reacts faintly alkaline towards litmus.
The solution is allowed to stand for 3 hours. 50 protein component comprises bleached horn
meal containing suf?cient $02 to impart to the
:Thereupon 160 grs. of this solution which, in de
reaction mixture a weakly acid reaction toward
pendence upon the character of the horn meal
utilisedj has been acidi?ed to give an acid re
6. A thermo-setting, protein-containing mold
action to litmus, is mixed with 50 grs. of horn
litmus.
meal, the product dried and, if desired after mill
ing subjected to the ‘hot pressing process de
scribed above.
Emample 3.-—50 grs. of urea and 10 grs. of
thiourea are dissolved in 150 grs. of 40% aqueous
.
-
'
55 ing composition capable of resisting the action of
hot water when in the hardened condition and
comprising the dried acidi?ed mixture of a pro
tein material and an initial, water-soluble con
densate of a urea and a greater than equimolec
formaldehyde solution and then neutralised with 60 ular proportion of formaldehyde in weakly
ammonia until the solution shows a faint alkaline
ammoniacal solution, substantially no degrada
tion of the protein material having taken place,
reaction towards litmus. The solution is allowed
said protein material being in the substantially
to stand for three hours. 160 grs. of this solu
tion which is faintly acidi?ed with phosphoric
unhardened condition, said composition being
acid is then mixed with 50 grs. of horn meal, 65 capable on molding at elevated temperature and
pressure of causing hardening of the protein
the product dried, and, if desired after milling,
is subjected to the hot pressing as above.
material by release of excess formaldehyde and
Example 4.-—40 grs. of urea and 20 grs. of
thiourea are dissolved in 150 grs. of 40% aqueous
' becoming infusible and insoluble.
7. A thermo-setting molding composition con
formaldehyde, then neutralised with ammonia 70 taining keratinous material uniformly distributed
therein and capable of resisting the action of hot
until the solution has a faintly alkaline reaction
towards litmus. The solution is allowed to stand
for 3 hours. Then 160 grs. of this solution,
water when in the hardened condition and com
prising the dried acidi?ed mixture of horn meal
and an initial, water-soluble condensate of urea
which is acidi?ed faintly with phosphoric acid,
is mixed with 50 grs. of defatted horn meal, the 75 and a greater than equimolecular proportion of
'4
2,256,253
Iormaldehyde‘in a. weakly alkaline ammoniacal
solution, the horn meal being substantially un
a?’ected by the ammonia and being in the sub-‘
stantially unhardened condition, said composi
tion, being capable on molding at elevated tem
perature and pressure of liberating su?icient free
formaldehyde to e?ect hardening of the kerati
‘ ' nous'material and becoming infusible and. in
soluble.
vproportion of formaldehyde to urea is approxi
mately 1.2:1.
9. Process according to claim 1, vwherein the
' initial condensation of the urea and formalde- -
hyde in the aqueous ammoniacal solution is con
ducted‘ for about three hours.
'
l
l
_ 10. A composition as set forth in claim 6,
wherein the urea is urea itself and wherein the
molecular proportion .of formaldehyde to urea
8. Process according to claim 1, wherein the '10 is approximately 1.2:1.
urea is urea itself and wherein the .molecular
- -
OSCAR NEUss.
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