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Патент USA US2106164

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2,106,164
Patented Jan. 25, 1938 7
UNITED‘ STATES‘ PATENT OFFICE
, cos'rnn FLEXIBLE snnn'r
Walter. Durgin Bowlby, Jersey City, N. 3., use
~signor to Egyptian Lacquer Manufacturing
Company, a corporation or New Jersey
-
No-Drawing. ApplicationAprll 1, loss,
'
Serial No. 73,184
20 Claims.
This invention is concerned with producing
?exible sheets having adherent protective coat
ings and contemplates in particular the produc
tion of novel lacquered papers.
5
In producing lacquered papers and thelike,
Throughout this specification and the append
ed claims, I use the term “base" to describe those
derivatives of carbohydrates, such as nitrooellu- _
lose, cellulose acetate, nitrostarch, etc., which
it is necessary that the dried lacquer ?lm be
are the major‘ ?lm-forming constituents in 6
modern lacquers. By "plasticizers” I mean the
strongly adherent, flexible, and non-tacky. Pref
class of softening agents such as-dibutyl phthal
erably the ?lm should be thermoplastic.
late, etc., which tend to reduce the brittleness of
lacquer ?lms and which remain in the film after
It is
also desirable that this ?lm be formed from a
10 lacquer in which the proportion of ?lm forming
ingredients is relatively high and the proportion
the solvent employed. has evaporated. I employ
of volatile solvents relatively low so that an econ
the term “solvent” to include those organic liq
uids such as aim] acetates, ketones, aromatic hy
omy in the use of solvents is enjoyed. Lastly, it
is desirable that the lacquer employed contain a
drocarbons, aliphatic hydrocarbons, etc., in
relatively large proportion of ?lm forming in
these compounds with each other or with dilu-~
gredients at the same time being sumciently fluid
ents such as alcohol. The term- “film forming
ingredient" is used to include lacquer “bases”,
plasticizers, resins and the like which have in
herent ?lm forming characteristics and remain
in the dried lacquer‘ ?lm after the solvent has
evaporated.- This term does not include pig
ments, ?llers, and like substances which do not
themselves have ?lm forming characteristics‘
even though they remain behind after the lac
quer solvent has evaporated and comprise a por 25
‘ to permit the production of a thick smooth dried
?lm in a single application.
.
As a result of my investigations I have found
2 O that excellent lacquered papers and the like can
be produced by employing nitrostarch as the
principal and preferably substantially the sole
base for the lacquer. Nitrostarch ?lms tend to
25
(Ci. 91-88) ‘
be both weak and brittle. I have found that the
weakness of nitrostarch ?lms used for coating
?exible sheets is relatively unimportant so long
as brittleness is overcome. ’ Nitrostarch ?lms
containing a su?lcient amount of plasticizer are
, very strongly adherent. In fact, 'suchsfilms ad
which nitrostarch is soluble, and mixtures of
tion of the dried ?lm.
_
.
The preferred lacquergof my invention con
talus’ only one base, nitrostarch, and in any
case, 'nitrostarch is the principal base and the
principal ?lm forming ingredient employed. The 30
ber ‘sheets and the like, that ?lm and backing ' addition of other bases, in particular nitrocellu
30 here so strongly to backings such as paper, rub
act almost as a unitary mass, the high tensile . lose, tends to cause segregation in the lacquer,
strength of the backing being sumcient to com
even when the viscosity characteristics of the
pensate for the relatively low strength of the nitrostarch and other base are substantially '
identical. Upon standing, 9. lacquer containing
35 ?lm containing nitrostarch.
I overcome the inherent brittleness of ultranitrostarch and nitrocellulose (both having vis
starch lacquer ?lms by adding a relatively large cosity chcteristics between t and t centi
amount of plasticizer to the lacquer. I have poises) separates into two layers unless a dis
found that in all cases the amount of plasticizer persing agent (such as an alkali soap) is present.
40 incorporated into the-lacquer used for coating This use of a-di'spersing agent to provide com 40
?exible sheets must-be at least ‘,/5 of the weight patibility between the two bases. has been sug-'
of the nitrostarch present. Unless an “anti
g‘ested heretofore, but I have found that such
tack” agent is incorporated into the lacquer the dispersing agents tend to segregate out of the
amount of plasticizer employed should not ex
dried lacquer ?lm, thus spoiling it.
stea
rates,'for example, tend to cause a bloom on the
45 ceed 1/; of the weight of the nitrostarch present;
otherwise the ?nal lacquer ?lm is soft and sticky. dry lacquer ?lm, thus rendering it unattractive.
Optimum results are obtained when the plas~ and less resistant to attack.
,
.
ticizer present ranges in amount from 42 to 46%
The nitrostarch which I prefer .to employ in
' of the weight of the nitrostarch in the lacquer.
50 It will be noted that the proportion of plasticizer
employed is greatly in‘ excess of the proportion
of plasticizer customarily incorporated into nitro
cellulose lacquers in which 5 or"10% of plasti
cizer by weight of nitrocellulose is ordinarily
ample.
the practice of my invention has a nitrogen con
tent ranging fromi11.5% to 12.5% and an aver
age viscosity characteristic ranging from 4 to 6
centipoises. Nitrostarch having a nitrogen con- ,
tent below 11.5% by weight tends to produce ex
cessively brittle ?lms. On the other hand, nitro
sta'rcli having a nitrogen content in excess of 55
2,100,164 '
nitrostarch of _ below about 42%. Ifithe ratio of plasticizervto
nitrostarch is above 46%, ?lm's of this thickness
the preferred nitrogen content, and is less read
ily soluble in most commercial lacquer solvents are very flexible and adherent, but are tacky un
12.5% is more combustible
and solvent mixtures.
less small amounts of one or more “anti-tack"
I
By viscosity characteristic, I mean the degree. agents such as petroleum jelly, para?ln, stearic
of viscosity which ‘is measured in a standard acid, or other suitable greasy substance is em
ployed. Usually 2 to 3% by weight of the lacquer
solvent into which a given proportion of a lac
quer base, say nitrostarch, has been dissolved. _ of an anti-tack agent is su?'icient toovercome
tackiness. ‘Films having a thickness approxi
- mating .002 of an inch are comparable in thick
have
reference
to
the
following
well
known
10
ness to the regenerated cellulose ?lms employed
The ?gures given for viscosity characteristic
method:
‘
'
A solution containing 12% by weight of ‘the
- lacquer base (say nitrostarch) in a solution con
sisting of 3 parts butyl acetate and 1 part ethyl
15 alcohol is prepared, and the viscosity of the solu
tion in centipoises at 25° C. is determined, pref
erably in a viscosimeter of the capillary tube
type, or by other standard methods. The result
ing determination in centipoises is taken as the
20 average viscosity characteristic of the lacquer
base undergoing investigation.
’
“
'
‘
aswrappinss.
The best anti-tack agents to employ are greasy
hydrocarbons such as petroleum jelly and paraf
?n. Stearic acid, or other crystalline substances .15
tend to form a bloom if used alone. The tendency
of. these materials to bloom. is inhibited by the
presence of hydrocarbons such as paramn. Thus,
when I employ fatty acids and the like, I also in
corporate substantially equal amounts of hydro 20
carbons in the lacquer.
_
Any suitable plasticizer may be employed, but
When it is realized that the so-called “low vis
cosity" nitrocellulose commonlyemployed in the . I prefer to use dibutyl phthalate, trlethyl citrate,
manufacture of automobile lacquers and the like ethyl phthalyi butyl glycolate, methyl and ethyl
has an average viscosity characteristic in excess
of 150 centipoises as measured in the foregoing
method, it- will be clear that the nitrostarch which
I employ in the practice of my invention has an
exceedingly low viscosity characteristic. It is in
large part due to this low viscosity characteristic
that I am able to put into solution up to 70% by
weight of the nitrostarch without increasing the
visccsitypf the resulting lacquer to a point which
precludes its application by customary methods.
ortho benzoyl benzoate, triphenyl phosphate, tri- I
cresyl phosphate, triacetin, or mixtures of one or
more of these substances. It should be noted
that triacetin, triphenyl phosphate and methyl
ortho benzoyl benzoate which are unsatisfactory
plasticizers for nitrocellulose’ lacquers, give ex 30
cellent results in the nitro-starch lacquers of my
invention.
.
'_
Lacquer modi?ers and agents for producing
special ?nishes, such as pigments, ?llers, metal
85
35 This proportion of base in lacquer is more than - powders, crystallizing agents, resins, dyes, etc,
/ double that of commercial lacquers which have may be added to the lacquer of my invention in
been employed heretofore and enables me to pro
' duce exceptionally thick coats on ?exible sheets in
one appllcation_and at the same time permits a
40 tremendous economy in the amount of solvent
employed.
_
My invention will be more thoroughly under
' stood in the light of the following detailed de
scription.
45
.
Lacquer is prepared according to any of the
suitable conventional methods, but in accordance
_ with one or more of the following rules of formu
lation:
'
‘
The lacquer base is preferably nitrostarch‘
I 50 alone, and in any case nitrostarch is the principal‘
. The nitrostarch base preferably has a nitrogen
content ranging from 11.5 to 12.5% and an aver
' age viscosity characteristic ranging below 6 centi
poises as determined by the method hereinbefore
set forth.
' ,
-
In no case should the plasticirer employed be
less than 20% by weight of the nitrostarch used.
For paper coating compositions from which the
dried ?lms weigh about 5 pounds per 3000 square
feet, 1. e., with a ?lm thickness below .0003'inch,
the ratio of plasticizer to nitrostarch may be kept
between 20% and 42% by weight. Such ?lms are
very thin, comparable in thickness to those for
65 merly produced on paper by spirit varnishes. If
the ratio of plasticizer to nitrostarch in the lac
quer is below 20% the ?lm is too brittle and the
accordance with well recognized conventional
methods of formulation.
For producing thick dried ?lms, the lacquer
preferably should contain 40% by weight of nitro 40
starch. With lacquer containing this proportion
of nitrostarch, a ?lm of the aforementioned thick
ness can beproducedon paper in a single‘- appli
cation. Irrespective of the thickness of ?lm to be
produced, it is desirable, of course, to employ as
high a ratio of solids (materials which remain in
the dry lacquer ?lm) to solvents (vehicles which '
evaporate) as possible, because this tends to de-'
crease loss of solvent. In general, lacquers of my
invention containing 40% and up of nitrostarch,
are to be preferred for applying even very thin
?lms to paper.
,
-
,
In accordance with my invention, the dried ?lm
which‘results from a lacquer in which the plas
ticizer is about 20% of the nitrostarch present will 55
ordinarily be such thatthe nitrostarch is about
83% of the total ?lm forming ingredients. On
the other hand a dried ?lm resulting from a lac
quer in which the plasticizer is equal to 50% of
the weight of the nitrostarch will ordinarily be
such that about 50% of the ?lm forming ingredi-.
cut is nitrostarch. Accordingly, nitrostarch come
prises about 50 to 83% of the ?lm forming ingre¢
dlents in. the dried adherent ?exible lacquer ?lms
on the ?exible sheets of my invention.
' The nitrostarch lacquers may be applied
paper and the like in the same manner that var
nish, etc, customarily are applied. Reverse roll
v
For paper coating compositions from which the machines, knife coaters, and various kinds of rolls
may be
Spray coating and brush applica 70'
-70 dried ?lms weigh about 40 pounds per 3000 square tion also produce satisfactory results. but these
feet, i. e., with a ?lm approximating .002 inch in
thickness the ratio of plasticizer to nitrostarch methods are relatively slow and expensive. '
Any kind of paper, cardboard, rubber and simi
should be between 42 and 46%. Films of this
" thickness tend to crack upon aging of‘ the coated -lar ?exible materials may be employed in the
75 paper if the ratio of plasticizer to nitrostarch is practice of my invention. Thus adherent, tough, 75
coated paper tends to curl.
3
' 9,108,164
where a permanently colorless or transparent
?lm is desired, my invention o?ers a further ad
durable, ?exible, brilliant and thick ?lms may be
produced on such materials with the nitrostarch
lacquers of my invention. I attribute the appar
vantage. Lastly, the lacquered papers of my in
vention are substantially free from any tendency
ent strength, toughness, ?exibility and durability
of these lacquer ?lms on ?exible backings to the
remarkable adhesion developed between the ?exi
to curl, shrink, or wrinkle, and cost less to manu
ble backing and the lacquer ?lm, whereby the
?lm and they backing are enabled to cooperate
teristic. The coatings are thermoplastic, i. e.,
"heat sealable" and impervious to moisture.
and the tensile strength of the backing is, in 'ef
fect, imparted to the whole mass.
The following formulae are intended to be
merely illustrative ‘of suitable paper coating com
positions made in accordance with my invention.
It will be understood that I do not limit myself
I claim:
lacquer ?lm in which the principal base is nitro
starch ‘and containing an amount of plasticizer
equal at least to 20% by weight of the nitrostarch
in the ?lm.
etc. given in the examples.
Formula 1
25
starch.
viscosity characteristic 4-6 centipoises___ 40
Para?in ________________________________ __
1
33
I
'
4. A ?exible'sheet having an adherent ?exible 25
dry ?lm oi lacquer in which the principal base
is nitrostarch having an average viscosity char
1 acteristic of from 4 to 6 centipoises, and con
Formula 2
taining a plasticizer in amount exceeding 20% by
.
Parts by weight
30
Nitrostarch'. ____________________________ __
?lm of lacquer containing at least 50 to 83%‘ by '
weight of nitrostarch and one or more plasticizers
Triacetin _______________________________ __
10
Methyl ortho benzoyl benzoate ___________ __
l0
Ethyl acetate ___________________________ __
30
...._...._ 190 ',
.
Formula 3
‘
Parts by weight
Nitrostarch
>
~
_30
Ethyl ortho benzoyl benzoate ___________ __
12
9
1.3
Ethyl acetate __________________________ __
Soluble_.._
25.0
13.7
Total
_ 100
3
'
Nitrostarch
Formula 4
Parts ‘by weight
____
'
5
17
Stearic acid __ ________________ __' ________ ..
1
Petroleum jelly _________________________ __
1
Butyl acetate______-_ _____________________ .._
15
Zyloi ___________________________ -_ ______ __
14
_..__
' 7. ~A ?exible ?brous sheet having an adherent
?exible ?lm of lacquer weighing‘ about 5 pounds
per 3000 square feet and containing nitrostarch 45
as its principal base, said ?lm also cpntaining a
plasticizer in proportions ranging from 20 .to
8. A ?exible ?brous sheet having an adherent
?exible ?lm of lacquer weighing about 40 pounds
per 3000 square feet and containing nitrostarch
so
2 -'as its principal base. said ?lm also containing
Triacetin _______________________________ __
Total
trlphenyl phosphate and .triacetin.
6. A ?exible ?brous sheet having an adherent
?exible ?lm of lacquer in which nitrostarch is 40
the principal base and containing from 42 to
42% by weight of the nitrostarch in the ?lm.
>
~
consisting in dibutyl phthalate, ethyl phthalyl
butylfglycolate, methyl ortho benzoyl benzoate,
. 46% by weight of the nitrostarch, of a plasticizer.
Triethyl citrate ________________________ __
Anti-tack agent (paramn) _____________ __
7 Percent solids-61.3
55
in excess of 20% by weight of the nitrostarch,
. said plasticizers being selected from the group 35
Total
50
30
5. A ?exible sheet having an adherent ?exible
Percent solids-70
45
weight of the nitrostarch. .
50
35
.
20'
amount exceeding 20% of the nitrostarch.
_‘_.
Total ______________________________ __ 100
Percent solids-62
“
3. A ?exible sheet having an adherent dry
?lm oi’ lacquer in which at least 95% of the base
is nitrostarch, and containing a plasticizer, in
5
Solvent mixture ________________________ _.~
15'
'
2. A ?exible sheet having an adherent lac
quer ?lm in which substantially all of the base
is nitrostarch, said ?lm containing a plasticizer
in amount equal to at least 20% of the nitro
Parts by weight
Nitrostarch, nitrogen content 11.5%-12.5%
Ester gum _____________________________ __
Dlbutyl phthalate ______________________ __
-10
‘
1. A ?exible sheet having an adherent ?exible
15 to the particular plasticizers, solvents, pigments,
20v
5
facture because nitrostarch is much cheaper than
nitrocellulose having a similar viscosity charac
100 _
an amount of plasticizer exceeding 42% of the
weight-o! the nitrostarch in the ?lm.
9. A ?exible ?brous sheet having an adherent 55
?exible ?lm of lacquer weighing about 40 pounds
per 3000 square feet and containing nitrostarch
as its principal base, said ?lm also containing a
plasticizer in amount ranging from 42 to 46% of
the weight of the ‘nitrostarch in the ?lm.
00
60 Percent solids-71
10. A ?exible ?brous sheet having an adherent I
By putting both petroleum jelly and stearic I '?exible ?lm comprising at least one coatv of lac
acid into this lacquer, tackiness is prevented, and
petroleum jelly prevents stearic acid from form
ing a “bloom” on the dried ?lm.
-
My invention, in addition to o?’ering a lac
quered paper on which the lacquer film is adhe
sive, ?exible, durable and tough, possesses~ out
standing advantages in that very thick ?lms may
be formed at a single application with the expen
70 diture of a small amount of solvent. Moreover,
65
quer about .002 of an inch thick in which the
principal base is nitrostarch, said coat also con
taining at least 42% by weight of a plasticizer 65
and a relatively small amount of a greasy sub
stance.
.
,
.
11. A ?exible sheet comprising paper having an
adherent ?exible coating in which the principal
base is nitrostarch, the coating also containing 70
the nitrostarch coating is substantially unadect
plasticizer in excess of 20% of the weight of the _
ed by actinic rays, so that it does not discolor
appreciably even after long exposure to strong
sunlight. In this respect my nitrostarch lacquer.
nitrostarch.
75 is superior to other paper ?nishes. Consequently
_
.12. A flexible sheet comprising paper having an
adherent ?exible coating in which the principal
base is nitrostarch having a nitrogen content 75
2,106,164
ranging from 11.5 to 12.5% as its principal ?lm
!ormingingredient, and containing a plasticizer
equal in amount to at least 20% of the weight
of the nitrostarch.
13. A ?exible sheet comprising paper having an
adherent ?exible coating containingnitrostarch
as its principal ?lm-forming ingredient and also
containing a plasticizer in amount equal to at
. least 20% by weight of the nitrostarch in the
10 coating.
14. A ?exible sheet comprising paper having an A
adherent coating containing nitrostarch as its
principal ?lm-forming ingredient and containing
a plasticizer in amount ranging from V5 to 1/z
'
15. the weight of the nitrostarch.
15. A ?exible ?brous sheet having an adherent
?exible dry lacquer ?lm in which 50 to 83% of
the ?lm-forming ingredients is nitrostarch, said
?lm containing an amount of plasticizer not less
20
_
_
equal, to at least V5 of the weight of the nitro
starch present.
17. A ?exible ?brous sheet having adhering
thereto a ?exible dry lacquer ?lm comprising one
-or more coats about 0.002 of an inch thick in
which from 60 to ‘70% oi’ the ?lm-forming in
gredients is nitrostarch having an average vis
cosity characteristic ranging from 4 to 6 centi
poise's, said coats containing a plasticizer in
amount'equal to at least 42%, oi’ the weight oi
the nitrostarch present.
10'
'
18. A ?exible sheet having- an adherent ?exible
lacquer ?lm at least .0003 of aninch thick in
which the principal base is nitrostarch, said ?lm
containing an amount of plasticizer equal at least 15
to 20% by weight of the nitrostarch in the ?lm.
19. A ?exible sheet having an adherent ?exible
lacquer ?lm of a thickness ranging from .0003
of an. inch to .002 of an inch in which nitro
starch is the principal base,v said ?lm containing 20
than % of ‘the weight of the nitrostarch in the an amount of plasticizer ranging from 20% to
46% by weight oi’ the nitrostarch in the ?lm.
20. A ?exible sheet having an adherent ?exible
thereto a ?exible dry lacquer ?lm comprising one lacquer ?lm at least .002 of an inch thick in
16. A ?exible ?brous sheet having adhering
25 or more coats about .0003 of an inch thick in ' which the principal base is nitrostarch, said ?lm 25
which from 60 to ‘83% v0! the ?lm-forming in
containing an amount of plasticizer which is at
gredients is nitrostarch having an average vis
least 42% by weight 01' the nitrostarch in the
cosity characteristic ranging from 4 to 6 centi
?lm.
'
WALTER
BOWLBY.
poise's, said coat containinga plasticizer in amount ~
1)
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