DE1446879A1 - Improvements in or relating to a method for making densified nitrocellulose particles - Google Patents

Description

910 Market Street, Wilmington, Delaware, U.S.A.

"Improvements in or relating to a process for

Production of compacted Hitrooellulose particles "

This invention relates to a process for the production of particles of diluted nitrocellulose which are used for the Solemegieases of fuel grains are suitable.

Relatively large grains of propellant powder which are for driving military rockets and missiles (guided missiles) suitable were after the coup: ^ erJEeqh "ik _v by ^M in situ" Giesse "-Teohniken manufacturers

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provided, in which dry, pre-colloid and compacted particles of a nitrocellulose preparation in a i'orm introduced and a pouring liquid of nitroglycerin and any necessary aids are then introduced into the "mold" to clear the spaces between to cover the dry casting powder particles and to be filled out. The mixture is then hardened in the mold until the particles of nitrocellulose casting powder enter the casting liquid absorb and the mass consolidates into a solid structure.

In-situ casting of propellant grains has a lot Disadvantage; it requires a large inventory of casting powder preparations and long curing times, and it does not itself lead to the production of grains of irregular composition, as they may be required to adapt to certain types of saket engines to create the desired type of ballistic puncture. Furthermore the known manufacturing processes for casting powder are lengthy and expensive because they involve the whole Include steps required to produce smokeless powder granules. Is was therefore suggested to produce large fuel grains by "slurry casting", at which relatively small casting powder particles and a pouring liquid are mixed together to form a pourable or flowable one Sludge, which is then poured into the 3? Οπη

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and the Gemiaoh then in the usual way in the form is hardened to form the propellant grain. Pure this Process, the small particles of colloidized, compacted nitrocellulose should be smooth and rounded, preferably have an ellipsoidal or spheroidal shape, and they should, in order to form a smooth, hard shell or outer wall of colloidized nitrocellulose at the surface of each particle, be sufficiently compacted. The interior of the particles can be like the surface envelope also be completely colloid and condensed, but the porosity associated with a partial Oloid or partially gelled status in the interior of the particles may be more desirable.

The hard shell of the colloidal nitrocellulose on the surface of the particles gives the soles a satisfactory "pot life ¹¹ (service life) by resisting the rapid absorption of the casting liquid and delaying the swelling of the nitrocellulose and the thickening of the sludge during the period of time required for production and is required to mix the slurry uniformly and then pour it into the mold. On the other hand, it is believed that some porosity inside the particles facilitates faster and more uniform curing after pouring.

In general, it will reduce the other factors

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remain essentially the same, the useful life the sludge with the decreasing size of the nitrocellulose particles and when a substantial majority of the mold powder particles are smaller than about 10 million in size.,. the useful life of the slurry, even if the particles are substantially completely compressed, is too short. On the other hand, if the majority of the mold powder particles are substantially larger than about 100 microns in size, especially if they are highly compressed, the! pot life of the sludge too long, whereby the particles da ~ to tend to settle from the sludge after pouring and to prolong the hardening of the grain excessively.

Although numerous manufacturing processes are relatively small particles of densified nitrocellulose are known, are none of them satisfactory? either the manufacture does not result in particles of a desirable combination of shape, size and density, or they are excessively tedious and expensive.

According to the invention is a method for producing compacted nitrooellulose particles which are used for slurry lakes of propellant grains, characterized in that a slurry is formed by stirring water-moist nitrocellulose fibers, which are essentially

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free ran IPaeereggregaten in a volatile mixture of hydrocarbon diluent and a miscible sitrocellulose solvent and in the presence of a "water-soluble protective colloid, the organic liquid emisoh a whitening and swelling agent for the nitrocellulose" fibers, is not able to dissolve them and the solvent is soluble in water to an extent of at least 2.5 öew.ji, the sludge is subjected to high levels of stirring until the softened and swollen fibers expand into smooth, rounded particles, the hardening of the particles is initiated by diluting the sludge with the hydrocarbon diluent while continuing high shear agitation and finally removing substantially all of the nitrocellulose solvent and water by distillation, in the presence of a tJbereohusee of diluent, to complete the hardening and densification of the nitrocellulose particles.

Sa · obig · procedure makes a soleplate harder, smaller, rounded·? and smooth-surfaced particles of compacted Nitrooellulose of essentially ellipsoidal and spheroidal oiter (It forms in the hydrocarbon diluent, from weloiieÄ da · terdlohtete litrooellulose product quickly in eiÄeai coal-fired status, through some-

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a conventional means that can be obtained as by Heavy drainage, centrifugation, suction filtering or similar, represent.

In the preferred process form of this invention, water-moist, fibrous nitrocellulose, after conventional treatments for stabilization and viscosity adjustment, padded with water and put in a Jordan machine or similar f fiber Dutch device smashed to the Breaking up fiber aggregates and shortening the lasers and producing an aqueous slurry of nitrocellulose fibers, which is essentially free of fiber aggregates. The excess water is then drained off, preferably filter by centrifugation or Sau ^, for production water-moist Hitr © cellulosefaser ^ which between about 35 and about 50 wt% sorted water, based on the total weight of the water-moist nitrocellulose fibers, contains. The terms "sorb" and "sorbed" as used herein in the usual manner the ability of nitrocellulose denote a To take in and hold liquid, either by adsorption or absorption, or by a combination of Adsorption and absorption, essentially independent of the gravitational forces. The resulting water moisture Nitrocellulose fibers are then introduced and dis-

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pergoes at essentially room temperature under violent conditions Stir like this by a Cowles Dissolver (Storehouse-C owles, Inc. 1150 San Fernando Road, Los Angeles, California) or the like, into a volatile, organic, liquid mixture of hydrocarbons diluents and nitrocellulose solvents, which is completely miscible with the specified diluent, with · the mixture only a softening and Swelling agent for the nitrocellulose fibers, incapable of dissolving of fibers, and dispersed therein contains a water-soluble one Protective colloid, to form a stirrable slurry of nitrocellulose fibers which essentially is free of fiber aggregates. The water-moist nitrocellulose fibers are converted into the organic, liquid Mixture introduced as fast as the agitator can disperse the fibers, either in small additions or when it is desired continuously. To complete the addition and dispersion of the water-moist The time required by nitrocellulose fibers in the organic liquid mixture is usually quite short and is usually only a few minutes. The softening, swelling and collapse of the nitrocellulose fibers begins as soon as the Fibers are fed into the organic liquid mixture.

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When all of the ITitrocellulose fibers are uniformly dispersed the sludge will then be passed to the Hochaoherri with a Kady Dispersion Mill (Kady Dispersion Corporation, 95 Botsford Place, Buffalo 16, New York) or similar, Subjected in a jacketed boiler, with cooling water in the jacketed boiler through the jacket to remove at least a portion of the heat generated in the slurry by the high-level stirring, circulates.

This high shear agitation is "significant and necessary as it is finally to soften and swell the nitrocellulose fibers and contributes to the breaking up of the softened and swollen fibers into small fragments ", a plurality the same surprisingly relatively uniform is in size. Sa's high shear stirring is also a significant object that contributes to the crushed fragments into smooth-surfaced rounded particles of. essentially ellipsoidal and spheroidal shapes to shape and the solution and uniform distribution of the water-soluble To facilitate protective colloids over the surfaces of the crushed particles. Although it's not exactly it is known what causes the size reduction, it is assumed that the entire objects or process forms of the invention are important. Hoohscher agitation is continued until substantially all of the fibers are chopped and shaped, and when

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the Beebaolitmi ^ welohe of the samples are taken at intervals, with the aid of magnification, shows t that no further size reduction and shaping will take place and that a substantial balance in the Sonlämme "with regard to örö'ase form and consists of the comminuted particles. Depending on the difficulty of the scaling down, this process can take anywhere from a few minutes to 2 hours or more.

It is believed that the protective colloid present in the slurry forms a thin protective coating or layer around each fragmented particle, thus retaining the fragments from sticking and agglomerating into substantially larger clusters. So hat colloid seems to support the shaping of the fragmented particles into the desirable ellipoidal waä- spaoidal shapes. Regardless of whether the above statements about the action of the antakoaioids are correct or not, the fact remains that the protective colloid is a necessary element of this invention, while in the absence of the Schutakolloida the fragmented particles tend to stick together and in ^ to agglomerate desired larger aggregates and not properly develop into rounded lipoid and phärol-shaped forms.

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When observation is a substantial condition of equilibrium, with regard to existence in terms of size and shape showing the crushed particles, the sludge will be with diluted while the hydrocarbon diluent the high shear stirring to initiate hardening of the crushed and molded objects is continued. The high shear agitation can be several minutes if desired continued to dampen the solvent, water and hydrocarbons from escaping from the slurry, to promote the further initial hardening of the particles to allow.

After the initial hardening of the crushed particles by diluting the slurry with the hydrocarbon diluent is performed, the nitrocellulose solvent and leave substantially all of the sludge by distillation to complete the hardening and compaction of the particles. The sludge should be grown during the distillation stage be stirred, but such stirring is not necessarily required Be high-watcher stirring; any means of payment is sufficient. Because part of the hydrocarbon diluent Likewise with the nitrocellulose solvent and water distilled, sufficient hydrocarbon diluent should be used the sludge, either before or during the distillation, can be added to achieve a greater

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BATH

Excess hydrocarbon diluent in the ensure entire distillation stages. The resulting hardened and densified nitrocellulose particles easily become in a hydrocarbon-rich state by removing the excess hydrocarbon liquid, by any conventional means, such as draining or drying by gravity, suction filtration, Centrifugation or the like obtained.

If desired, various additives such as cellulose stabilizers, Furnace soot and other desirable additives which are in the organic liquid mixture soluble or dispersible, are introduced into the slurry at any suitable point in the process and very uniform in the nitrocellulose product be distributed.

The hydrogen hydride product of this invention is composed of small, hard, compacted, essentially rounded nitrooellulose particles, preferably essentially of ellipsoidal and spheroidal Shapes having a variety of particle sizes with a substantial majority of them between about 20 microns and about 80 microns, preferably between about 40 miorons and about 75 microns in diameter

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Large is between a total range of particle sizes about 1 mioron and about 200 microns. The absolute Density of these small particles on a dry basis is at least about 1.3 g / ccm, the absolute ■ Density of the fully densified nitrocellulose is approximately 1.65 g / com. Are these particles in the magnification considered, they have smooth, dense, glassy surfaces and generally have a degree of porosity, inside the particle. The bulk density of these particles is at least about 40 pounds per cubic foot, preferably at least about 45 pounds per cubic foot on a dry basis. Although somewhat irregular in particle shape, in terms of deviating from the ellipsoidal and spheroidal shapes, are acceptable no more than about 5 $ of such irregularly shaped particles in the form of elongated fiber-like particles.

The small compacted particles of this invention will easily in aqueous or organic, liquid mixtures, for the formation of hydrosol, organosol or plastisol preparations dispersed, which produces uniformly smooth, pourable slurries with a relatively high solidity, stop are. A plastisol mixture of JO parts by weight of compacted Particles of this invention, uniformly mixed with 70 parts by weight of triaoetin, which is a solvent type

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Softener for nitrocellulose, forms a smooth,
Pourable slurry which, after 1 hour at room temperature, is still pourable and has a viscosity less than 4000 oentipoises. This explains an important, satisfactory "pot life" (service life) for the use of the small compacted particles in slurry casting of large blowing agent grains, and this Characteristics, combined with other described properties, with regard to the particle shape, size, density, surface and mass density characteristics, make the small,
compacted particles of this invention are particularly good for
Used in slurry casting of large fuel grains
suitable.

The small densified nitrocellulose particles of this invention are used at between about $ 10 and about $ 30
Wt. I "sorbed hydrocarbon liquid moistened
and are further characterized by being good
Have fluidity and are relatively incompressible. The chemical properties of the product
of this invention are apparently the same as the conventional nitrocellulose as there is no chemical action in the manufacturing process of this product
is carried out.

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Although the production of small particles of densified nitrocellulose, which for use in casting propellant grains by the slurry casting process of a of the objects of this invention, it is clear that the usefulness of the compacted particles of this invention, is not limited to the use of slurry casting large grains of propellant as these compacted Particles, either in the hydrocarbon wet state or dried, are used in any application where commercially available nitrocellulose is now used, such as varnishes, plastics, paints, adhesives, Coatings, printing inks, impregnating agents and the like. With regard to the small particle size and Form, coupled with high bulk density, are the densified nitrocellulose particles of this invention as well suitable for the production of nitrocellulose wood fillers which are essentially free from any tendency to shrink, if they are coated with nitrocellulose lacquers and other coating materials, which have solvent carriers that are solvents for nitrocellulose. This use is described in more detail below.

The general nature of the invention is illustrated below, and the following examples are specific inventions

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Purpose of the same without restricting the scope of the invention. All parts and percentages are by weight unless otherwise stated.

example 1

Water-damp fibrous nitrocellulose, $ 12.6 nitrogen, based on weight, 5 seconds 5 / 16th of an inch falling ball viscosity, measured according to Military Spec. JAN-N-244, following conventional treatments for stabilization and viscosity grading slurried with water and in a Jordan mill to break up the paser aggregates and shortening the fibers, and a slurry of nitrocellulose fibers which is substantially free of There was a build up of fiber. This slurry was then centrifugally dewatered to $ 63.83 total solids drains.

23.5 parts of this water-moist nitrocellulose, which contained 15 parts of nitrocellulose, dry weight, and 8.5 parts of water, were then mixed in an organic, liquid mixture of 42.8 parts of Laotol spirits, a petroleum, at room temperature with stirring -Kohlenwassers toffraktion having a boiling range between 201 ° and 217 ⁰ F and a Kauri butanol value of 41, and 33.6 parts of methyl ethyl ketone, which in itself dispersed 0.1 part

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containing water soluble methyl cellulose, in a stainless steel Steel kettle fitted with a Cowles dissolver introduced and dispersed. This took about 5 minutes Stir with the Cowles dissolver operating at approximately 4000 revolutions per minute.

The charge was then transferred to a jacketed Kady dispersion mill fitted with a lid, cooling water circulating in the jacket, and was subjected to high shear agitation at about 16,000 revolutions per minute in the covered Kady dispersion mill for about 30 minutes. The temperature of the slurry reached the range between approximately 60 and 64 ⁰ C and was then kept in this temperature range by jacket cooling during this period of high shear stirring. The slurry was then diluted with 11.2 parts by weight of lactol gasolines, the lid of the Kady mill removed, and high shear agitation continued for an additional 30 minutes. During this latter period of high shear agitation, evaporation of the methyl ethyl ketone, water, and lactol gasoline components from the sludge was evident and additional lactol gasoline was added as needed to level the liquid in eggs Maintain mill.

The charge was then continued with Laotol gasoline

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diluted and placed in a distillation kettle equipped with a stirrer of the conventional propeller type wax, where the remaining water and methyl-ethyl-ketone were removed by distillation while stirring the charge. A total of approximately 48.5 parts by weight of additional Laotol gasoline was used for diluting the slurries during the latter period of high-boiling point agitation with the Kady dispersion mill with the lid removed and prior to removing the remaining water and methyl ethyl ketone in used in the distillation kettle. The distillation was stopped when the distillation temperature to boiling point of the Laotol gasolines, about 95 ⁰ O erreionte. The remaining slurry of small, compressed Hitrooellulosepartikeln in Petroleumverdün- nungemittel was then by suction filtration to 80 wt. Fo solids content (total) of liquid drawn off.

The remaining compacted nitrocellulose particles had an absolute density of 1.357 g / com trooken and a bulk density of 52 pounds per cubic foot on the trooken surface. The total particle size was in the range of 40 mlOTon. to 150 microns with a majority of the particles in the range of 50 microns to 75 miorons. The visual examination with the aid of magnification showed that the particles were smoothly rounded and old, dense glassy surfaces

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for the most part had elliptical and spheroidal shapes * The dried material flowed easily like dry sand,

5 parts by weight of dried particles were mixed with 7 parts of triacetin to produce a soft, pourable slurry which was still easy to pour after 5 hours. The viscosity build-up of this slurry was "at the specified time at 2O ⁰ G as follows:

(Minutes) ^{15 5} ° ^{45 60 75 90 105 120 180 24} ° ⁵ °°

viscosity
(centipoises) 102 112 127 145 170 186 210 235 460 1040 2920

These particles were satisfactory and well suited for use in slurry casting large grains of blowing agent.

The viscosity property of the nitrocellulose after the 1/6 th of an inch ball was determined according to the Military Spec. JAN-N-244 for a 10% by weight solution of nitrocellulose with a solvent * composed of 11.1% denatured ethyl alcohol and 88.9% by weight acetone at 25 ^° G, while recording the time in seconds for the 10th inch f pure fall of a 5/16 inch steel ball through the solution, measured.

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Example 2

Water-moist, fibrous nitrocellulose, 11 wt. ^ Nitrogen, approx. 154 seconds ASIM 5/16 inch falling ball viscosity, was slurried with lasser after conventional treatments for stabilization and viscosity adjustment and treated in a Jordan machine to break open the fiber aggregates and shortening the fibers and for Preparing a slurry of nitrocellulose fibers which is essentially free of fiber aggregates. This slurry was then centrifugally drained to $ 64.1 total solids dehydrated content.

The ASTH 5 / i6tel inch falling ball viscosity property of the nitrocellulose was performed on a 12.2 wt. ^ Solution of nitrocellulose in a solvent composed of 55 $ toluene 2596 denatured ethyl alcohol and 20 $ Äthylaoetat, each based on the weight, at 25 ⁰ C, measured, recording the time in seconds for a 5/16 inch steel ball to free fall 10 inches through the solution. 25.1 parts of this water-moist nitrocellulose, which contained 16.1 parts of nitrocellulose on a dry basis and 9 parts of water, were then introduced and dispersed at room temperature with stirring in an organic, liquid mixture of 43 »3 parts of Laotol-Benainen and 31 »5 parts of methyl ethyl ketone, which in itself

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dispersed, 0 _f 1 parts of water-soluble methylcellulose were dispersed in a stainless steel kettle equipped with an Oowles dissolver. This required about 1 minute of agitation with the Gowles dissolver operating at about 40000 revolutions per minute.

The batch was then transferred to a jacketed kady. Dispersion mill fitted with a lid with cooling water circulating through the jacket and was subjected to high shear agitation in the covered Kady Dispersion Mill operating at about 16,000 revolutions per minute for about 30 minutes. The temperature of the slurry reached the range between about 60 and 64 ⁰ C and was then maintained by jacket cooling during this period of high shear agitation. The slurry was then diluted with 7.45 parts by weight of Laotol gasoline and high shear stirring continued for an additional 2 minutes with the lid removed.

The feed was then continued at approximately 48.5 wt. Share Lactol-Gasoline and dilute in one with agitator equipped distillation kettle, where the remaining water and methyl ethyl ketone are removed by distillation became. The distillation was interrupted when the destination temperature reached the boiling point of the Laotol gasoline

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reached, around 95 ⁰ O, and the slurry of hardened, compacted nitrocellulose particles in lactol-gasolines was brewed back into the Kady dispersion mill and subjected to about 1 minute of Hoohsoh agitation to break up some users, aggregates formed in the still kettle. The resulting slurry of small, compacted nitrocellulose particles in petroleum thinner was then removed by suction filtration to a total solids content of 80% by weight.

The resulting densified nitrocellulose particles had an absolute density of 1.570 g / cc and dry a trooken base bulk density of 51.6 pounds per cubic foot. The total particle size was in the range of 25 microns up to 150 microns, with a majority of the particles in the 40 to 60 micron range. The visual inspection with the help of the magnification showed that the eartikel smooth and rounded with dense glassy surfaces. Wanig fiber-like Particles, essentially less than about $ 1 in number, were observed.

The hydrocarbon-moist nitrocellulose particles dieäes Example were used in a wood filling application as follows »

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The following ingredients were mixed and matched together on uniform distribution in a pony mixer, aur manufacturing the wood filler preparation, mixed "

Components Parts by weight hydrocarbons-moistened nitro- cellulose particles (80 wt. fo Ni trocellulose) 14.2 VM&P naphtha 16.1 Methyl abietate 11.2 silver-bonded silicon dioxide (Silver Bond Silica) (Filler quality) 42.0 3 χ asbestine (magnesium silicate) 10.0 Brown iron oxide 0.2 Bus s 0.3

total

94.0

This formulation was made on $ 60 solids with VM&P naphtha thinned and brushed onto open-grain mahogany boards, which are preceded by a nitrocellulose wash-coat with an oily solution of nitrocellulose in added to a conventional nitrocellulose solvent mix and had been dried. The wood filler formulation was allowed to dry quickly for approximately 10 minutes, after which time the excess! filler preparation from the plates in the traditional way, across the grain of the wood with a

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The rag was roughened and the plates were left for about 1 hour let dry. A conventional system of nitrocellulose loosening coatings was then applied by spray coating the filled panels consisting of one Application, or a coating of Mtrooelluloseelaokporenaohliesser and two final orders from Nitrocelluloselaok, taking each coat of paint before applying the next application or the next coating Let dry non-sticky. The painted panels then left to air dry overnight., and she were then tested for the filling effectiveness of the above nitrocellulose filler both before and after polishing observed in direct comparison, to similar plates, which are made with a conventional, commercially available oil type filler, before applying the nitrocellulose release coating, were replenished.

The above nitrocellulose filler formulation filled the Pores of the wood in an effective way, and the extent of the observed! Filling was equivalent to that * which was observed with the conventional commercially available oil type filler.

Examples 3 to 9

Rows of finely divided, densified nitrocellulose particles were produced, essentially using the

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same procedure as described in example 1, followed. The same wasaer-moist nitrocellulose, prepared in the same way as described in Example 1 is, was used in these series »In the Examples 3 to 6 including Laotol gasoline, as a hydrocarbon diluent with methyl ethyl ketone used as nitrocellulose solvent and the ratio of hydrocarbon diluent to nitrocellulose solvent was changed. In Examples 7 to 9, heptane was used as the hydrocarbon diluent with methyl ethyl ketone as Nitrocellulose solvent used and the ratio of hydrocarbon diluent to nitrocellulose solvent was changed.

The following table I gives the relevant data relating to the type and quantity of components used, Process Details Relating to Dispersal Agitation, Highly stir and dilute with hydrocarbon diluent relate and properties of the particles obtained.

The densified particles of any of Examples 3 through 9 were satisfactory and good for use in slurry casting of large grains of blowing agent, as well as for. ^z ' Use for the production of nitrocellulose oil filling

substances suitable.

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Components 8.5 (Parts by weight) water-methylo-
pulp
nungsm. 0, 1 Tabel I. Procedural details; 11.2 2 Additional sales
thinning d. Nitrocel
lulose
(Sr OQk.
Approved) let 8.5 ethyl
ketone
iT 0, 1 High to high initial high to high
Kadyrüh- dilute, stir n.
, ren d.Sohlämi- initial
* "" Minutes me m.Koh- dilute.
_{> n} lenwas s er-m. removed.
fabric cover
thinimgsiTi tlffinut © !!
s5 * start fl—
hardening 11.2 - Hydrocarbon
dumb matter,
medium z. De
stilling
¹ U »" RTlClltSTtTliTig at
game 15th 8.5 25.7 ₍ 46.6 ⁽¹ ) 0, 1 .Behavior.
Cabbage.what-
dilute, τ
MA
ethyl-
ketone. Jowlei
lührei
linutf 30th 11.2 2 48.5 3 15th 8.5 29.6 44, ε ⁽¹⁾ 0, 1 1.98 5 60 11.2 30th 48.5 4th 15th 00 00
WW
vn vn 31.6 42.6 < ¹ ) 0,
0, 1
1 1.57 1 30th 11.2
11.2 15th
15th 48.5 5 15th 8.5 33.6 40.0 < ² > 0, 1 1.41 5 30th 11.2 10 48.5 £ 15th
15th 34.6
35.5 39.4 (2) 1.27 5 30th
30th 48.5
48.5 V \ co
co
0 »
—A 15th 37.0 1.18
1.13 5
5 15th 48.5 ί ¹ 1.06 5

^ 'means lactol-benzine (iactoi spirits)

(2)

^v 'means heptane

CD CO

Table I (continued) Properties of the compressed particles

absolute
density
dry

Bulk density
Dry basis
Tbs / cu.ft.

Particle size total - majority range range micron micron

Viscosity of 30 wt. $ Ν ·. Sludge
trοck.Particles in Tr iac et in after 2
Hr. At 2O ⁰ C.
Centipoises

Findings regarding particle shape, surface, etc.

1,540

1.621

1.638

47.0

4th 1 , 502 44 , 0 5 1 , 520 50 6th 1 , 357 52 7th 1 , 631 41 , 6

40.2

40.8

25-150 40-70

20-100 40-60

25-150 40-70

40-200 45-75

25-150 30-60

25-150 30-60

25-150 30-60 2.550

smooth, rounded, with dense glassy surfaces :; the majority of the particles are irregular - deviating from ellipsoidal and spheroidal ones To shape.

smooth, rounded, with dense glassy surfaces the particle ellipsoid u * spheroid in shape;

smooth, rounded, mostly with dense glassy surfaces the entire particles are ellipsoidal and spheroidal in shape

smooth, rounded, with dense, glassy surfaces; mostly the entire particle is ellipsoidal and spheroid in shape. '

smooth, rounded, with dense glassy surfaces, majority of the particles are irregular
different from the ellipsoidal and spheroidal forms; very few, less than J $ according to the number, fibrous particles

smooth, rounded, with dense glassy surface- • the majority of the particles' either
ellipsoidal and spheroidal in shape or roughly ellipsoidal and spheroidal shapes

smooth, rounded, with glassy surfaces? mostly the entire particle ellipsoid and
spheroid in shape.

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Examples 10 to 13

Rows of finely divided, compacted nitrooellulose particles were prepared by following essentially the same procedure as described in Example 2. Fibrous nitrocellulose with 11.0 wt. $ Nitrogen and 45 ASTM 5 / 16th ball drop viscosity was in the seconds Examples 10 and 11 used and 11 $ nitrogen and Seconds ASTM viscosity in Example 12 and fibrous nitrocellulose of 11.0 wt. ^ nitrogen and 1/4 of a second ASTM 5/16 inch Ball-Pall viscosity was used in Example 13. IN Examples 10 and 11 was the part of the methyl-ethyl-ketone solvent, which is normally used for the purposes of this invention by anhydrous Butanol replaced.

The following Table II gives relevant data that sioh on the type and amount of the ingredients used, procedural details that sioh on the dispersal stirring, Stir hoohso and dilute with hydrocarbon thinner relate and the properties of the particles obtained.

The densified particles of any of Examples 10-13 were satisfactory and good for use in the manufacture of nitrocellulose wood fillers, as well for use in sole casting of large fuel grains suitable.

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Table II Beatand parts (parts by weight)

Nitrocellulose

Procedural details

At- Ifew. # ASTM Amount Was-Methyl-Bu-Iactoi- wass. Rat. Cowles high initial loss additional loss Stick- 5 / i6inch ser äthyl- tabbenzine soluble lactol- fi carry shear thinning d. thinning d. fabric ball! skirt. ketone nol methyl-benzi- Minut. Kady sludge m.. Sludge m.

Fall viscosity wt. Sec.

cellu-ne too loose methyl ethyl ketone or comm. v. methyl ethyl ketone and butanol

run lactolbenzi-Iactolbenzi-Minut. nen z.Annen z.Distilfang hardness. lation and final hardening

10 11.0

11 11.0

12 11.0 15 11.0

45

4-5

154

16.6 16.6 16.1

1/4 16.1

9.3 19.8

9.3 16.3

9.0 31.5

9.0 16.0

4.5
8.0

49.6
49.6
43.2
58.8

0.1
0.1
0.1
0.1

2 * 04 2.04 1.37 3.67

30 30 50 30

7.45 7.45 7.45 7.45

48.5 48.5 48.5 48.5

O CO OO

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Table II (! Continued) Properties of the compressed particles

At- absolute bulk density particle size

play tight © on dry- total- majority-

I taioolcen- basis area area remarks, regarding Particle shape, surface, etc.

g / oom lb / cu. ft. micron microm

10

12th

1.556 1.564 1.564 1.540

41.6

50.0

50.7

55.7

25-150 40-70

25-150 40-70

20-150 40-70

15-150 40-60 smooth, rounded, with dense glassy surfaces, mostly the entire particles ellipsoid and spheroidisoh: in the form

smooth, rounded, with dense glassy surfaces, mostly the entire particles ellipsoid and spheroid in the F

smooth, rounded, with dense glassy surfaces, mostly the entire particles ellipsoid and spherical in shape

smooth, rounded, with dense glassy surfaces, mostly the entire particles ellipsoid and spheroid in shape; very few, essentially less than $ 1, in terms of number, fiber-like particles

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- 30 examples 14 "to 18

Rows of finely divided, densified microcellulose particles were prepared by following essentially the same procedure as described in Example 2. These series used nitrocelluloses that were different in both nitrogen content and 1/16 inch ball-eal viscosity property, and the resulting particles in each example were smooth and rounded, with dense glassy surfaces, and for the most part were the particles essentially ellipsoidal and spheroidal in shape. The hydrocarbon-wet Ni tr O ^- solute particles from each of these examples were used in a wood fill application as described in Example 2, with essentially the same desirable results as recorded in Example 2. The following Table III provides relevant data relating to the nitrogen content and the Ball-Pall viscosity properties of the Ixtroeellulose types used, together with the absolute density, bulk density and the particle size range of the particles obtained, and observations with regard to the filling efficiency of the wood filling preparations which are made from the densified nitrocellulose particles.

- 31 909816/0116

Table III Nitrocellulose

_B. Nitrogen- 5 / 16t »l inch ^^ ΧΓ

-ΪΪΙι ^Gew - * Ball-Fall- 252J _n

S ^piel Viekosität * / * °° ^βη

^Ηγ seconds ^ ⁰⁰¹ *

Bulk density particle size

Total dry basis ^
lb / cu. ft. rich
micron

Wood

Majority- flushing area we came-

mioron speed

CO
CD
CO
OO

11

12.6

11

11

11

(2)

₃₂

(D

- 45.7 10-80 11-30 excellent 1,540 47 25-150 40-70 excellent - 51.6 25-150 40-60 excellent 1,540 55.7 15-150 • 40-60 excellent - 50 30-150 40-60 excellent

'' Viscosity measured according to the ASTM method given in Example 2.

(2)

^K ' viscosity measured according to the Military Spec. JAN-iM-244 as given in Example 1.

- 32 Example 19

Finely divided, diluted nitrocellulose particles were produced by following essentially the same procedure described in Example 1, with the exceptions that acetone as a nitrocellulose solvent instead of methyl ethyl ketone, which is used in Example 1 was, and also no Hoehsoherriihren after the Initial dilution of the sole ridge with hydrocarbon dilution. thinning agent for initial hardening. They are like water-moistened nitrocellulose, which is in the prepared in the same manner as described in Example 1, and the same petroleum hydrocarbon diluent, as used in example! have been used in this example.

Relevant seeds, in terms of type and amount of ingredients used, process details related to Bispereal stirring, Hoohsoe stirring and dilution with hydrocarbon diluent, and properties of the particles obtained are summarized in Table IV below. They made particles were satisfactory and well suited for use in invert casting of large grains of propellant.

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/ y

. - 33 Table IY

Nitrocellulose, dry water
acetone

■ Laotolbenaine

water-soluble methyl cellulose ratio: laetolbenzine / acetone Oowlesrüliren
Hoohs oher Kady fees

Initial dilution of the sludge with laotol benzine for initial hardening

Additional dilution of the sludge with laotol benzine for distillation and final hardening
absolute density of the particles, trooken bulk density, trooken basls
Viscosity of the 30 ffew. ^ Igen soles drier

15th Parts 8.5 Parts 20th Parts 56.4 Parts 0.1 Parts 2.82 Parts 2 Minutes 30th Minutes

11.2 parts

48.5 parts

1.459 g / oom 44.2 lb / cu.ft.

Particles in triacetin after 2 hours at 20 ° C

Particle size, total area Particle size, majority area Remarks regarding particle shape. Surface, etc.

1,875 oentipoises

30-150 micron 50- 75 micron

The particles were smooth and rounded, with dense, glassy surfaces and mostly by ellipsoideq? and spheroidal shape.

The small, compacted ffitroisellulose particles of these Invention can be made from any fibrous nitrocellulose obtained by nitriding natural or man-made cellulose fibers, such as cotton, purified Cotton linters, cleaned wood pulp, regenerated Oellulose fibers and the like, in such forms

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like roughened linters, frayed wood pulp, flocked mass linters, finely ground or chopped Fibers, fiber aggregate particles and the like. However it is' It is important that the fibrous nitrocellulose is essentially free of fiber aggregates for use in this invention, because such aggregates prevent their own comminution and lead to the formation of undesirably large particles,

Accordingly, it is both desirable and preferable fibrous nitrocellulose starting from a conventional Jordan crushing process or similar treatment to break up fiber aggregates and generally to shorten the fibers prior to use in this invention. To achieve this will be the water-filled, fibrous nitrocellulose, after conventional treatments for stabilization and viscosity division, with water to the consistency of a conventional one Pulp sludge is slurried on and in a Jordan machine or similar fiber-breaking device beaten to break up and break apart the fiber aggregates and generally to shorten the fibers. The excess water is then removed by any conventional method, preferably by centrifugation or suction filtration to water-moist nitrocellulose fibers produce which is between about 35 and about 50 wt. sorted water, based on; the total weight of the water-moist nitrocellulose fibers,

90981670116,.

- 50 -

H46879

produce, and these water-damp fibers are immediately ili the 'inventive method used because the water to dissolve and uniform distribution of the water-soluble Protective colloid over the surfaces of the shredded fiber fragments is required. These water-humid ones Hitrocellulose fibers feel moist and contain sufficient water for the purpose of this invention. Although Uitrooellulose fibers, which a larger amount Water as indicated above could be used, no benefit is thereby gained. Moreover, it is because Water removed in the process of this invention is economically undesirably more water than indicated above to use.

nitrocellulose fibers, softened with one of the lower alkanols, such as methanol, ethanol, propanol, isopropanol, butanol, Isobutanol, sea-butanol or tert-butanol dehydrated can be used in this invention. In these cases, however, the alcohol causes dehydration not in the place of the water, which for the second This invention has been indicated as necessary, and an amount of water, as outlined above, should dehydrate the alcohol Hitrοcellulose, preferably before dispersing added to the nitrocellulose in the organic, liquid swelling and white raw medium. Replaced for it dehydrating alcohol is an effective nitrocellulose solvent, approximately weight part for weight part.

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H46879

All commercially available types are available for loan and grades of fibrous nitrocellulose for the purposes this invention suitable, which nitrogen contents of have about 10.9 "to about 15» 5% by weight nitrogen " and some viscosity property of the very low Viscosity, from the 10 oentipoise type to the extraordinary High viscosity types such as dynamite nitrocellulose.

The heated nitrocellulose fibers are introduced and dispersed in an organic liquid bulking and swelling medium of this invention with vigorous agitation Formation of a uniformly smooth, easily agitated sludge ι the upper practical grense of the amount of nitrocellulose fibers in the mud, «Luroh's ability becomes the To stir sludge effectively is intended. In general, slurries ranging from about 10 to about 20 wt. ^ Fibrous nitrocellulose, based on the dry weight, contained, used and preferably between about 14 and about 18 sewing. $ nitrocellulose. Although softening consistencies of any concentration below about 10 wt. # Can be used, «· not regarded as economical, · ο to proceed.

The organic liquid öemisoh, which is used as a medium for the reduction and compression of nitrocellulose is used, is a mixture of CARBON hydrogen diluent

909816/0116 - 37 -

solvent and nitrocellulose solvent, which in perfect. Way is miscible with the designated diluent. It is important and necessary that the ratio of the hydrocarbon diluent and nitrocellulose solvent in the mixture is such that the Q-emisoh is only a swelling and wetting agent for the nitrocellulose fibers, but is incapable of dissolving the specified IPaaern. Suitable proportions of hydrocarbon diluent and nitrocellulose solvent to achieve this end depend primarily on the particular hydrocarbon diluent and nitrocellulose solvent chosen and on the nitrogen content and viscosity properties of the nitrocellulose to be shrunk and densified. If, for example, mixtures of lactolbenzines and methyl-ethyl-ketone are used as a medium for the reduction and compression of the nitro-cellulose fibers with a nitrogen content of 12.6 $ and about 5 seconds 5/16 of an inch Ball-Pall viscosity, the ratio of the Laotolbenzine to methyl-ethyl -ketone iia mixture between about 1.25 and about 2.0 Q-parts. If heptane is substituted for the aotolbenzine and methyl-ethyl-ketone and the same nitrocellulose are used, the ratio of heptane to ethyl-ethyl-ketone in a mixture can vary between about 1.0 and about 1.2% by weight . If you use mixtures of Irtiotolbenzinen and acetone as a medium for

909816/0116 - ₃₈ -

Crushing and compaction of nitrocellulose from Stiokatoff and 5 seconds viscosity, the ratio of Xaotolbenzine to acetone in the Geinisoh can be between approximately 2.6 and about 3 * 3 weight cords wakefulness. Used one mixtures of laotolbenzinen and methyl-ethyl-ketone as a medium for crushing nitrocellulose from $ 11 Nitrogen and 45 seconds viscosity, the ratio of Laotol "benzines to methyl-ethyl-ketone in the mixture alternate between about 1.3 and about 2.1 parts by weight. If you use nitrocellulose from $ 11 nitrogen and 1/4 of a second viscosity with mixtures of Laotolbenzines and methyl-ethyl-ketone, the ratio can be Change Laotolbenzine to methyl ethyl ketone in a mixture between approximately 3.3 and approximately 3.9 parts by weight.

However, it is with any particular selection of hydrocarbon diluent and nitrocellulose solvent a simple means a preliminary experiment to be carried out by slurrying the desired nitrocellulose in the selected hydrocarbon diluent B-medium and then progressively adding the selected nitrocellulose solvent with stirring until the point is reached where the Gemisoh begins to swell the fibers the above examples can serve as a guide. It is then a simple matter of performing of this invention is small in the ratio of hydrocarbon diluent to nitrocellulose solvent

909816/0116

'- to make or reductions, _f to the desired en forms Diohte bulk density range of particle sizes and the like to obtain.

Any volatile hydrocarbon, which is liquid at ordinary temperatures and atmospheric pressure can be used for the purposes of this invention Solely aliphatic, cycloaliphatic, aromatic

sohe, arylaliphatic and aliphatic-aryl hydrocarbons, and mixtures of any of these. Some typical hydrocarbons are poured in by way of example, Hexane, heptane, octane, isootane, nonane and similar, various protected petroleum distillates of various boiling ranges such as textile gasoline,! test gasoline, Laotol gasoline, YM 4 P naphtha, gasoline, kerosene and similar, oyolopentane, oyoloheian, methyl-oyolohexane, benzene, (toluene, xylene, Ethyl-benzene, styrene, alpha-methyl-styrene, various Protected aromatic hydrocarbon distillates of various boiling ranges, mixtures of aliphatic and aromatic hydrocarbons and the like. The preferred hydrocarbons for the purposes of this invention are aliphatic hydrocarbons which boil in the range of heptane or higher.

Hitrooellulose solvents which are used for the purposes of these Invention are suitable, are the Niedermolekulargewiohtketone, Esters, GKLycolether alcohols and GKLyoolether esters

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- 40 -

which in water to an extent of at least approximately 2.5% by weight are soluble. Some typical nitrocellulose solvents, welohe for the implementation of this

finding are suitable, include, for example, Methyl formate, ethyl formate, methyl acetate, ethyl aoetate, Isopropyl acetate, methyl propionate, acetone, meishyl ethyl ketone, Diethyl ketone, ethylene glyool monomethyl ether, Ethylene-glyool-monoethyl-ether, methoxyethyl-aoetat and similar. Preferably this should be nitrocellulose solution. medium a boiling point below the boiling point of the hydrocarbon diluent, have or should have a minimum boiling azeotropic mixture with the carbon

form with hydrogen diluent and / or water; Methyl ethyl ketone is particularly useful for the purposes of this invention suitable because in addition to suitable solubility in water and formation of a boiling point Mixtures with water and also free from the slope is to hydrolyze.

Bs has already been stated above that a water-soluble Protective colloid for. the practice of this invention requires and essentially any water-soluble soot colloid of this invention can be used. Some typical suitable water-soluble protective colloids an exemplary water-soluble alkyl ether of cellulose, hydroxyalkyl ethers of cellulose, mixed ι Alkyl-hydroxyalky1-ether of Oellulos ·, «1 · Methyloelluloee,

9 0 9 816/0116 j

- 41 -

■ - 41 -

Ä-fekyloellulost, Hydroxyätiiyloelluloae, Hydroxypropyloellulose, Methyl-hydroxyethyl-oellulose, Btethyl-hydroxypropyl-oelluloee, Ethyl-hydroxyethyl-oellulose and similar water-soluble alkyl ethers of starch, hydroxyalkyl ethers of starch, mixed alkyl-hydroxyalkyl ethers of Starch, such as methyl starch, ethyl starch, hydroxyethyl starch, Hydroxypropyl starch, methyl hydroxyethyl starch, Methyl hydroxypropyl starch and similar alkali metal and ammonium salts of alginic acid, such as sodium alginate, Ammonium alginate, potassium alginate and similar} alkali metal and ammonium salts of eaphthalene sulfonic acid and lignobulfonic acid j alkali metal and ammonium salts of G-luouron- ,. Salaoturonic, Manuronic and related acid-S structures, which is present in various vegetable glues, pectins and gumsj polyoxyalkylene-glyoole, such as polyoxyethylene glycol, polyoxypropylene glycol and the like Addukt® from ethylene oxide and Honyl phenol and others ... In the present case, water-soluble methyl cellulose is preferred to water-soluble protective colloids.

The water-soluble soot colloid can either be in dry » powdered or granulated form or as a water solution aeapsel'ben are added. Anyhow it is preferred to add the protective colloid in trooked form, because that is present in the water-heated nitrocellulose fibers Water to effect dissolution and uniformity Yerieilung the water solution protective colloid over

909816 / 01t6 ₄₂

H46879

- 42 the surface of the crushed particles is sufficient.

The amount of water-soluble protective colloid used should not be greater than is compatible with the ability of the colloid to coat the crushed particles with a thin but effective protective film and will ' generally between about 0.1 and about 0.5 weight percent based on the total weight of the slurry. Amounts, are substantially less than about $ 0.1 generally insufficient for the purposes of this invention, and amounts greater than about 0.55%, although they are effective in coating the crushed particles with a protective layer, unnecessarily increasing the presence of a water-sensitive component in End product.

Although a Kady dispersion mill in the examples, was used as an agent, the nitrocellulose fibers high Subjecting shear stirring, the invention is hereby in no way limited in this direction, because any high speed abrasive mill is effective is, for example, a Premier Oolloid Mill

or similar device.

- 43 -909816/0116

Claims (1)

- 43 claims Δ Process for the production of compacted particles of nitrocellulose, suitable for the sole casting of Ireibmittelköraern, characterized in that a SoTiT amme is formed by. Stirring water-moist nitrooellulose fibers, which are essentially free of fiber aggregates, in a volatile mixture of a Kohl enwas a he st off diluent and a miscible nitrooellulose solvent and in the presence of a water-soluble skin colloid, the organic liquid mixture being a white and swelling agent for the nitrooellulose fibers and is incapable of dissolving the same and the solvent is soluble in water to an extent of at least 2 »5 wt It is initiated by diluting the sludge with the hydrocarbon diluent while continuing to stir the hydrocarbon, and until essentially all of the ifitrooellulose solvent and water are removed by distillation in the presence of excess diluent, to the end the hardening and compression of the nitrocellulose particles. 2 · Method according to claim 1 daduroh! 909816/0116 - 4-4 - that a petroleum hydrocarbon diluent is used and the nitrocellulose solvent methyl ethyl ketone is. 3. The method according to claim 2, characterized in that the petroleum hydrocarbon diluent boils ^{between 190 and 24O 0 P.} 4. The method according to claim 3 »characterized in that that the diluent boils between 201 and 217 ° F. 5. Verfanren according to claim 4, characterized in that the diluent is heptane. 6. Verfa ^ en according to claim 2 or 3, characterized in that that the nitrocellulose has a nitrogen content of about 11% by weight. 7. The method according to claim 2, characterized in that that the nitrocellulose is a rough type with a nitrogen content of at least 12.6 G-ewo ^ S. 8. The method according to any one of the preceding claims, characterized in that the initial ratio of hydrocarbon diluent to nitrocellulose solvent in the sludge is between 1.25 and 2.0 parts by weight. Q- method according to claim 8, characterized in that that the "designated initial ratio between 1.0 and 1.2 G-ew · 909816/0116