JPS60237926A - Flocculated cellulose particle and its production - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION This application is a C-1-P application of U.S. Patent Application No. 482366 filed on April 5, 1983, and U.S. Patent Application No. 482366 was filed on February 2, 1983. This is a C.■.P application of U.S. Patent Application No. 463,100.

This invention was invented by 1.91 Kei Rei, and relates to aggregated cellulose particles which are used particularly as bedding materials for animals, and a method for producing the same.

Commercial cat bedding often contains soil.

This bedding is heavy, dusty, and has the disadvantage of clumping at the bottom of the bedding box after use. In addition, soil bedding has low absorbency, so cat urine tends to accumulate at the bottom of the bedding box, and it also increases the growth of bacteria, causing odor problems.

In an attempt to address the shortcomings of earthen bedding, other commercially available cat bedding materials are made from cellulosic materials such as newspaper and alfalfa. These products contain water-soluble binders and are made by extrusion and petting of extrudates.

However, such products also have drawbacks. In particular, during use, the pellets expand and break, resulting in soiling of the bedding box. Furthermore, these products are dusty despite the presence of binder because the exposed edges of the pellets are not protected by a hardened skin.

Therefore, it is an object of the present invention to provide a lightweight, dust-free, absorbent, easy-to-clean, and free-liquid wick that evaporates absorbed moisture and limits bacterial growth.
The object of the present invention is to provide particles that are particularly useful as bedding materials for animals.

Another object of the present invention is to provide particles that have other uses such as floor cleaning materials, oil absorbents, filler materials, mulches or carriers for other materials such as perfumes, disinfectants, disinfectants, etc. .

Hikarihada Q Overview-i Generally, the present invention relates to agglomerated cellulose particles particularly useful as animal bedding and methods of making the same. The particles of the present invention can be made from fibrous cellulosic waste materials such as waste paper, newsprint, paper mill sludge, and combinations of these cellulosic waste materials, and thus represent a means for converting waste materials into useful products. I will provide a. The particles of the present invention are absorbent, light in weight, can be disposed of in containers, and have very low dust generation. The particles of the present invention maintain their integrity and do not clump together when heavily wetted. Even when immersed in water, these particles maintain their integrity after becoming saturated.

This statement is surprising because the particles are primarily or substantially connected by ribbed hydrogen bonds. This property is particularly advantageous when the particles are used as cat bedding.

More particularly, the present invention provides that the particles consist essentially of agglomerated fibers, aggregates of fibers, and/or fiber-sized pieces of fibrous cellulosic material, said particles comprising protruding fiber ends and/or the substance of fibrils. It has an unusually dense or compacted outer surface or skin. [For purposes herein, "fibers" are irregular aggregates of fibers or fibrous material. (See Figure 9) Because the particles are formed by agglomeration in the presence of water, the particles are essentially held together by hydrogen bonds. Further, since a binder is inherently present in the fibrous cellulose waste material, it can exhibit slight adhesion. Additionally, small amounts (up to about 10 weight percent) of binders such as starch may be added. However, for reasons of cost and especially because the particles of the present invention are relatively dust-free and the integrity of the particles is well maintained without binder, it is preferred to keep the addition of binder to a minimum. The shape of the particles is substantially irregular, but is preferably platelet-like, as explained below. Considering that the particles are formed from fibrous cellulosic material;
The compressed surface is relatively smooth. Depending on the nature of the fibrous cellulosic material used to form the particles, the internal fibers of the particles will vary. For example, about 0.635cm
If shredded waste paper containing small pieces on the order of 1/4 inch (1/4 inch) is agglomerated, the particles will have a distinct lamellar or lamellar structure. On the other hand, if a more finely divided material is used, such as paper mill sludge, a more homogeneous internal structure is obtained. Nevertheless, the rolling action of agglomeration 1-2 imparts a small degree of internal orientation to the particles, even when using very finely divided feedstocks.

This orientation appears to be an inherent feature of the agglomeration method used to create the particles.

In another aspect, the present invention provides a) wet fiber blends, fiber aggregates, and/or waste paper, and/or paper mill slug 7
b) agglomerating fibrous pieces of fibrous cellulosic feed material such as fibrous particles to form individual U condyle; b) compressing the surface of the agglomerated particles to substantially form protruding delicate ends and/or protruding fibrils; C) drying the agglomerated particles. Preferably, the particles are flattened slightly prior to final drying to form platelet-like particles that are less likely to roll. This term is particularly advantageous when the particles are used as animal bedding.

In yet another aspect, the present invention provides a bed of particles in a container, such as a bedding box, wherein the particles consist essentially of aggregated fibers, fiber aggregates, and/or fibers of fibrous cellulosic material. The present invention relates to a particle bed consisting of size pieces, characterized in that the outer surface of the particles has a dense or compacted skin substantially free of protruding fiber ends and/or protruding fibrils. Preferably, the particles have a platelet-like shape.

As cat bedding, the particles of the present invention produce very low dust generation and minimize adhesion to the bottom of the bedding box during use.

These and other aspects of the invention will be described in more detail with reference to the drawings.

Figure 1 shows in detail the preparation process for the feedstock r1 used in the method of the present invention. FIG. 1 shows an apparatus for producing fibrous cellulosic material that is connected to an IHA feedstock for agglomeration. “Fibrous cellulose material” as the object of this application
and C, it is a fibrous cell material that does not substantially contain natural binders naturally present in the body of plants such as lignin, tar, and pitch. These natural binders are great! This makes the ululose-based material open and non-flexible, which is not preferred for the purpose of the present invention.

These binders are usually removed by extraction during the paper pulping process. Cellular I-su based materials that are digested in bulbized culms are therefore particularly suitable. Such particularly suitable materials include waste paper (including newsprint, cardboard, etc.), paper mill sludge, and It is a mixture of these.

"Paper mill sludge" as used in this application means -
Next Teisosh II! Sludge and papermaking in the king factory-r'
, is a broad term that includes other sludges from 1 to 21, and is passed through the forming wire of the wet papermaking process.
The dehydrated waste from paper mills is defined as 1 mm of 1-su short fibers. Preparation of raw materials shown in Figure 1
1.It is not necessary for all cellulosic fiber materials, such as paper mill sludge, to be directly applied to the culms of the present invention, unless the moisture content is high enough to prevent coagulation. Supplied. However, paper mill sludge can be processed in the process of Figure 1 with other raw materials to the extent that its water content does not particularly adversely affect the fiberization process.

In particular, FIG. 1 shows how a bale of waste paper 5 is conveyed by a belt conveyor 6 to a suitable breaker 7, and by means of a briefing cuff the bale is brought into a shape that is easier to handle. The bale material crushed by the hale breaker 7 is deposited on another conveyor 8, is weighed by a scraping roller 9, and is placed on a third conveyor 8.
is placed on a belt conveyor II and passed through a metal detector 12. This metal detector 12 is used to inform the operator that if any metal is present, it will cause damage to the next device and must be removed. The undesired material is deposited in the transportable box 13 by a suitable device such as a pivotable deflection plate 14.

Next, the fibrous cellulosic material is transferred to a belt conveyor 15.
to one or more fiberizing or milling devices, such as a hammer mill 1G, 17, for example. These fiberizing devices 1G, 17 are designed and operated in a manner known to those skilled in the art of fiberizing technology. The purpose of the hammer mill or other attrition equipment used herein is to grind or fiberize the raw material into fiber-sized pieces (including individual fibers and aggregates of fibers) (for this purpose, ""Fibersize" is approximately 174
inch x 174 inch (approximately 6.35 mm x 6.35 m
m) means the following size. The larger the fiber size particles, the more difficult it is to process the material into smooth surface particles in this application. ). Pressurized air is continuously added to the hammer mill through line 18 to keep the material flowing through the hammer mill. The special fibrous cellulosic material processed through the hammer mill consists of 25% by weight newspaper, 60% by weight clay-coated glue grade waste paper (clay-co
ated glue-grade wastepape
r ) and 15% by weight of primary tissue mill sludge (containing approximately 75% by weight water). A typical paper mill slurry contains about 60-90% water by weight, so if fed in large quantities it can clog the hammer mill and can cause problems. Hammer mills can become clogged if the total moisture content of the fibrous cellulosic material is on the order of about 20% by weight. Therefore, when using paper mill sludge, a dry feedstock must be formulated to "dilute" the moisture. To avoid such problems, paper mill sludge may be added to the system after the hammer mill process. Of course, if the paper mill's Sula 7
If the raw material is used simply as a feedstock, the raw material preparation step shown in FIG. 1 is not necessary.

The fiber size of the resulting fibers, agglomerated fibers and/or fibrous cellulosic material is transferred from the hammer mill 17 through conduit 21 with the aid of additional forced air flowing in line 19 to a fiber settling drum 22 where the material is precipitated. carried.

Fines and dust present in the air space above the settling fibers are drawn out of the fiber settling drum 22 through a conduit 22 and directed to a bag house 24 .

In the bag house 24, fine powder and dust are removed from the air. Filtered and recycled or discarded.

A suitable fan 26 provides a means for drawing air and debris into the bunkhouse. Other debris conveyed through line 2B from a dust hood located in the hopper of the screw feeder of FIG. 2 is also directed to the baghouse.

FIG. 2 illustrates the process of the present invention, i.e., agglomerating fibers, agglomerated fibers, and/or fiber-sized pieces of m-male cellulosic feedstock to form individual agglomerated particles; 3 illustrates a method of compressing the surface of the particles and drying the particles. As will be clear from this specification, it is not necessary to accomplish the steps of agglomeration, surface compaction and drying in three separate parts of the apparatus. Typically, one device may agglomerate the particles and compress the particle surface at the same time, or compress the particle surface and dry the particle at the same time. In fact, one device can accomplish all three process steps, as described in connection with FIG. Referring again to FIG. 2, the fibers, 7 agglomerated fibers, and/or fibers from a suitable source, such as the fiber settling drum 22 of FIG. A feeding device such as a hopper 31 of a screw conveyor 32 is fed.

This screw conveyor 32 serves to meter and feed the feed material to the mixer 33. Additional ingredients such as odor absorbers (e.g., sodium bicarbonate, activated carbon, borax, etc.), antistatic agents, flame retardants, etc. may be added to the extent that such additives are desired as process aids or to impart certain properties to the final product. Optionally, it can also be added at this point in the process to provide additional benefits. Antistatic agents are particularly effective in reducing the tendency of final product particles to stick to animal fur when used as cat bedding. Conventional ammonium salts such as d-coco-dimethyl-ammonium chloride or methylbis(2-hydroxyethyl)cocoammonium nylate are suitable antistatic agents for this purpose and are suitable for the air dry weight of the fibrous cellulosic material. It can be added at a level of about 0.5 to about 5% by dry weight based on B. Dust generated in the hopper can be removed by a suitable ventilated hood system directing the dust into the bag house.

In mixer 33, the fibers, agglomerated fibers, and/or fiber-sized pieces of fibrous cellulosic feed material are thoroughly mixed with a sufficient or nearly sufficient amount of water for aggregation. Agglomeration is a process in which particle size increases around a nucleation site by successive transfers of particles. This movement increases the exposure of the growing particles to small pieces of fibers, agglomerated fibers, and/or fiber sizing of the fibrous cellulosic feedstock, thereby allowing the mechanical twisting and attachment of the fibers to bring them closer together. provide opportunities for contact and growth. It has been found that once a moderate moisture level is achieved for a given mixture of fibrous cellulosic materials, agglomeration occurs very easily. As the moisture level of the mixture is further increased, larger and more agglomerated particles are formed. Of course, if too much moisture is present, a slurry will form and no flocculation will occur. Thus, first, the mixer serves to control the fibrous cellulose feed to the subsequent agglomeration step. In this way, the size of the aggregated particles is somewhat controlled by the moisture level. The mixer consists of a tubular vessel with an inlet 34 and a series of internally rotating teeth or paddles 35 (paddles are illustrated) that mix and move the feed materials toward an outlet 39. If teeth are used, virtually no agglomeration occurs within the mixer. However, it has been found that if paddles are used, some agglomeration occurs within the mixer. This is an advantage since it reduces the work on the subsequent equipment that performs the agglomeration. Preferably, the mixer includes a number of water inlet boats 3G, 37 and 38 as desired to achieve adequate moisture control. Warm water is preferred if available. The reason is that it softens cellulose fibers more easily. A specific device that has been successfully used is manufactured by W Ferrotic (Model 12T35). It has been found to be advantageous to add water at each stage shown to provide good distribution. For example, about 80% of the water to be added to the mixer is
can be added through port 37 and the remainder through port 38.

The moisture content of the mixed material leaving the mixer is from about 50 to about 80% by weight based on the air dry weight of the cellulosic fibers.
However, the level of precision must be optimal for the particular feedstock and particular agglomeration equipment to be used.

At this stage of the process, the water-containing material exhibits some agglomeration, but overall the material can be described as a very loose and brittle material with little clumps of individual particles.

The wet fiber blend, fiber aggregates, and fiber-sized pieces of fibrous cellulosic feed material exiting the compounder are then placed into a rotating mechanical agglomeration device 41. This equipment primarily serves to roll the wet material into agglomerated particles and to complete the agglomeration that occurs in the compounder. 1 Agglomeration can be achieved in a suitable rotating device such as a rotating disc type agglomerator or a horizontally rotating drum. For example, ferotic (F
A disk-type agglomeration device manufactured by erro Tech, Inc., having a 3 foot (91,44 cm) diameter disk pinched at a 47° angle and rotating horizontally at approximately 27 r, p, m, has been found to be suitable. I understand. However, a substantially horizontal rotating drum is preferred. This is because the drum is not expensive and provides good agglomeration while compressing the surface of the particles to form a dense skin as described below. A drum 5.5 feet long (167,640I11) with an internal diameter of 23 inches <58.42 cm rotating at 22r, p, m produces approximately 50 pounds (22,5 kg) of air-dried cellulosic fiber per hour. has been found to be sufficient for aggregation purposes.

Although a substantially horizontal rotating drum is the preferred level,
The drum is tilted slightly to increase or decrease the average residence time of the particles as desired. The ends of the drum are open except for the circumferential wall at the inlet end to prevent material from falling out. Movement of particles from one end of the rotating drum to the other naturally occurs as the particles go to the lowest level and fall out the exit end of the drum. The space occupied by the particles within the rotating drum is relatively small based on the internal volume of the drum. Typically, the particles occupy only about 2% to about 5% by volume. This allows particles to slide up the inside of the drum during rotation,
When it reaches a certain point, it is dropped to the bottom of the drum or reversed,
This creates a mixing or rolling action. If necessary, additional water 42 can be added to the flocculation device to further enhance the flocculation process. For example, it is advantageous to add some water at this point if it cannot be removed.We have found that additional water of about 0 to about 30% by weight is advantageous. This can be easily achieved with an injection nozzle positioned at , preferably close to the drum inlet, in order to give the material to be agglomerated the necessary agglomeration wetness as quickly as possible.The moisture content of the material at this point is approximately Should not exceed 85% by weight and preferably should not exceed about 80% by weight if cat bedding is the desired end use of the particles.A high wet size would result in a particle composition that is too large for this purpose. can be caused.

The agglomerated particles 43 exiting the aggregator typically have a moisture content of about 75 to 80% by weight. Particle size typically ranges from about 1732 inches (0,079 cn+) to about 5
/8 inches (1,59 cm) or more. The particles are separated with a vibrating Expandisoto metal screen 46 to remove particles larger than 5/8 inch (1,59 cm), which are recycled through conduit 47 to the hammer mill. These particles are preferably removed because they are too large for side bedding and are more difficult to dry than smaller particles. However, the particles retained for further processing end up shrinking in size by about 30% by the time they dry. Therefore, particles larger than the desired final size can be retained at this stage of the process.

The agglomerated particles exiting the aggregation device also contain a large number of protruding fiber ends and/or fibrils. These exposed fiber ends and fibrils are undesirable if the particles are ultimately to be used as cat bedding.

This is because these exposed fiber ends and fibrils allow these particles to stick to the cat's fur and thus be carried out of the litter box. Therefore, it is necessary that the surface of the aggregated particles be substantially smooth (see Figure 5).

One way to achieve this is to compress the particle surface, for example by rolling or bouncing the wet particle in a vibrating fluidized bed dryer, in which the particle surface is partially dried. It is compressed with only Similar surface compaction can also be achieved, for example, in a substantially horizontally rotating drum. In fact, it is preferred to use a substantially horizontal rotating drum in which the agglomeration is effected by a second substantially horizontal rotating drum which provides the surface compaction. The second drum surface is preferably Teflon coated to improve surface compaction by preventing particles from sticking to the inner walls. The particles undergo a stage of surface compaction at least about 1
This surface compaction step not only helps reduce the number of protruding fiber ends and fibrils, but also improves fiber-to-fiber bonding at the surface. Increase the strength of hydrogen bonds on the particle surface by increasing the bond. Compaction gives particles a smooth surface and also resists dust formation,
and gives the particles a denser skin that allows them to retain their integrity when heavily moistened.

Returning to the second point, particles of acceptable size that pass through the screen 46 have their surfaces compressed or further compressed to reduce moisture content, preferably about 30% by weight.
The hot air is then directed to a fluidized bed dryer 48 to reduce the amount of air to a minimum. The particular dryer found suitable is 32 square feet (2,94 m2) with 3% open area.
with a vibrating floorboard surface of 16 feet in length (4,8
8m). Agglomerated particles enter the dryer at inlet 49 and exit the dryer through outlet 51. Approximately 380F (90”
c) hot air (standard 6700 cubic feet per minute);
(187,6rrr/+win) enters the entrance 52,
6 of the floor plate is directed upward through a number of orifices.

Air is exhausted at outlet 53. Particle residence times of about 30 seconds to 60 seconds have been found to be suitable.

This is approximately 172 inches (
This corresponds to a fluidized bed height of 1.27 cm (at rest). In operation, the fluidized bed of particles has a very low density. actual,
Small particles can be placed about 1 foot (30,48 cm) above the floorboards.
) can rise to a height of Larger particles will only tend to roll along the surface of the floorboard, being urged towards the outlet by the vibratory movement provided by a suitable vibratory device connected to the floorboard. The dust contained in the output from the dryer can be directed to a bunkhouse for disposable or recirculating use.

The surface-compacted agglomerated particles exiting the first fluidized bed dryer 48 typically have a moisture content of about 30% by weight. A moisture content of about 15 to about 50% by weight is believed to be adequate to provide good surface compaction and still maintain particle integrity during subsequent processing. The shape of the agglomerated particles at this stage of the process is generally spherical,7 but not uniform or irregular. However, the surface of aggregated particles is smooth. If desired, the surface-compressed agglomerated particles 55 may be sieved with a second vibrating screen 56 or IJ.
Large and/or small unnecessary size particles 57 can be removed.

The acceptable particles 58 are then directed to a final drying device, such as a second vibrating fluidized bed dryer 60, where the particles are dried to less than about 10% by weight moisture, preferably about 5% by weight. Inhibits bacterial growth which is enhanced by high moisture levels. Since the purpose of this fluidized bed dryer is simply to dry the particles, it is economically advantageous to operate the fluidized bed at a much higher density than in the first dryer. Typically, the floor height is approximately 1 or 2 inches (2.54 cm or 5.08 cm) during operation, so the amount of air supplied to the bed through conduit 61 is approximately It's less compared to that. By way of example, approximately 3000 cubic feet per minute (8.4 nl/ml) of hot air (475'F (119C)) is typically supplied to the final dryer. The final dryer should be physically identical to the first dryer. Further, the residence time of the particles is preferably approximately the same as the residence time of the particles in the first dryer, but can vary widely as desired. Obviously, the design of both dryers can be varied by those skilled in the art to meet the needs of a particular device.

The dried and surface-compacted agglomerated particles 70 exiting the second dryer are preferably transferred to a third vibratory screening device 7.
1 to remove particles that are too large or too small for the desired end use. These particles can be recycled to the hammer mill. The preferred screening device shown includes l/16 inch (0,16
Particles with diameters up to 72 and 378 inches (0,96 cm)
A double screen is used which recirculates particles 73 with a diameter of cm) or larger. (As used herein, "diameter" refers to the maximum length dimension of a particle, and is not intended to mean that the particle has a true circular or spherical shape. (Not intended.) This size classification has been found to be preferred for animal bedding9. As shown, the allowable particles 75 exiting the central portion of the screen can be recovered as the final product if desired;
It is placed in a bag and packed. During packaging, fragrances, such as encapsulated fragrances or oils, can be mixed with the dried particles to improve product acceptance.

FIG. 3 shows an optional stage suitable for the process of FIG. 2 in which surface compacted particles are transferred to a fluidized bed dryer
After partial drying and sieving at 8, the particles 58 are shaped into platelets in suitable equipment.

This can be accomplished, for example, by conveying particles 58 into a nip between press roll 80 and conveyor belt surface 81 to flatten the particles. The conveyor belt is driven and supported by rolls 82 and 83. This changes the shape of the particles from approximately spherical to what is referred to herein as "platelet" (see Figure 6). This is advantageous because the platelet-like particles are less likely to roll off when scattered on the floor during use, thereby confining the particles to a small area for cleaning. This stage keeps the particles in a wet state (
It is important that the process be carried out on particles of about 15% to about 50% water (by weight). On the other hand, in wet conditions, particles tend to adhere to each other if pressed together under sufficient pressure.

It is therefore preferred to deposit the particles on the conveyor heald in substantially a single layer to avoid combining several individual particles into large single clumps. If the size or height of the particles varies significantly between the particles present at this point in the process, it is advantageous to separate and flatten the small, medium and large particles separately. Otherwise, for example, if the nip gap is set for large particles, small particles will pass through without being sufficiently flattened.

FIG. 4 shows another alternative embodiment of the method of the invention, in which some of the journeys shown in FIGS. 2 and 3 are omitted. The method is accomplished by using a single, nearly horizontal, rotating drum to carry out several steps: agglomeration, compaction of the surface, and partial drying. The method can be carried out by extending the length of the rotating drum sufficiently to accommodate the functionality of the method. As shown, as in the previously illustrated embodiments, a suitable fibrous cellulosic material is deposited in a hopper 31 which transfers the material to a screw feeder 32.
supply to The materials are metered into the inlet 34 of a blender 33, preferably of the rotating web type to allow for a certain degree of pre-agglomeration. As already shown, the web 35 is supported on an axial rotational shaft which mixes and moves the materials to the outlet 39. Water addition is provided through the inlets 36.37.38 as previously described.

The wet formulation material is thus deposited in a more or less horizontal rotating drum 41, which is similar except for its length to the rotating drum already described. For a production rate of approximately 79 kg (approximately 175 pounds) of air-dried cellulosic fiber per hour,
Approximately 366cm (approximately 12 feet) in length, approximately 58cm in inner diameter
(approximately 23 inches) and a rotational speed of approximately 25 r, p, m seems suitable. Inside the drum, near the inlet, a series of optional water injection nozzles 90 are suitably placed to provide the necessary additional flocculating water as previously described. The two nozzles are suitably connected to a water source 91.

At a location near the outlet of the drum, hot air from a suitable source 93 can be directed onto the particles by suitable nozzles 96. Alternatively or additionally, the surface of the drum or a portion thereof may be externally heated. In such an embodiment, the drum has a second
Coagulation takes place in the first zone, as already explained in connection with the figure. In the second zone, after addition of water and agglomeration, the particles are continuously rolled over each other to compact and/or further compact the surfaces of the particles. Third
In the zone, the particles are partially dried by hot air, preferably to about 30-50% moisture 3, and the surface is further compacted.

The partially dried particles 98 emerging from the rotating drum are screened by a vibrating screen 46 as previously described, dried in a fluidized bed dryer 60 as previously described, and dried as previously described. If necessary, they are screened again on the vibrating screen 71. Optionally, the particles exiting the screen 46 can be flattened into platelets prior to final drying, as described in connection with FIG.

FIG. 5 is an enlarged photograph (approximately 4.5x) of a representative particle of the present invention, which appears to have an irregular, round spherical shape for the purposes of the present invention. . As can be easily seen from this photo, the surface of the particle consists of large bumps (b
ump), but the surface of this nub is relatively smooth and there are fiber ends or fibrils with almost no visible protrusions.

FIG. 6 is a photograph similar to FIG. 5, showing representative particles of the present invention, which particles appear to have a platelet-like shape in accordance with object 4 of the present invention. These particles are simply particles similar to those shown in FIG. 5 that have been slightly crushed or flattened so as not to reduce their spherical shape as explained above. To illustrate the flattened size, the platelets in this photo are
Attached at the edges, showing a flattened form. These same particles, when viewed from the above photo where the particles are on a flat surface, appear rounded and look very similar to the particles in Figure 5.

FIG. 7 is an enlarged photograph (8x magnification) of a cross section of a representative particle of the present invention, which consists of 25% newsprint, 60%
The clay coated glue grade wastepaper is formed from a feedstock consisting of 15% tesos to create a sludge as previously described. As you can see from the photo,
In fact, the internal structure, which is somewhat layered, is less dense in the center of the particle as opposed to the dense outer surface or skin that completely surrounds the particle. The presence of a dense skin is very important to maintain the integrity of the particles and minimize the formation of lumps when highly moist. Skin formation is due to surface compaction caused by rolling action during and after agglomeration.

FIG. 8 is an enlarged (8x) cross-sectional photograph of representative particles of the present invention formed from a feedstock consisting of tissue manufacturing sludge as previously described. Similar to the particles shown in FIG. 7, these particles also have a densified surface compaction skin around their less dense interior. Although the internal structure does not form layers like the particle shown in FIG. 7, there is some directionality in the internal structure that appears to run approximately parallel to the surface of the particle.

Figure 9 is an enlarged (approximately 4.5x) photograph of the fibrous cellulose-based feed material exiting the formulation before the first agglomeration stage. As is evident from the photograph, some agglomeration has already occurred at this point in the process, but optimally the surface of what is referred to as large agglomerates of material is not densified and is dominated by free fiber ends and fibrils. covered. These six types of structures should be avoided. However, in large-scale production, only a small amount of particles with protruding fibers or fibrils may be present in the product. However, these problems involve quality control and are outside the scope of the present invention.

As mentioned above, the agglomerated particles of the present invention are metric and highly absorbent. Typically about 0.2 per l c+J
Agglomeration density from g to approx. 0.3 g and approx. 2 g per gram of particles
It has the absorbency to absorb approximately 2.5g of water. These properties will, of course, vary depending on the nature of the materials supplied, process conditions, the presence of additives, etc. Furthermore, when used as cat bedding, the particles of the present invention produce less dust than commercially available soil-based cat bedding.

To illustrate this point regarding dust, a test was conducted to measure the amount of dust produced by pouring a bag of cat bedding particles into a bedding box. (The weight measurements of the duram units collected in this test can be referred to as the “Dust Level Index”7).
8.1 cm (15 inches) high by 12.7 cm (5 inches) long plastic cat bedding box, 55.9 x 38.1 square centimeters wide and 17.8 cm (high inches) A Plexiglas(TM) cover was specially fitted to measure the volume of the sample.

The cover has a hole at one end measuring an area of 15.2 cn+ (6 inches) in diameter. Large capacity sampler with tarred glass fiber filter [Mine Safety Appliance (Mine 5a)
A Fixt Flo collector manufactured by Fety Appliance was attached to this hole. The opposite side of the cover has a series of small holes that create airflow from one end to the other inside the assembly. The top surface of the cover also includes a diameter 20 mm for injecting the test sample.
．． A 3 cm (8 inch) hole was made. In the test, the sample air sampler was first turned on. The volumetric flow rate of air through the sampler is 0.61128 n/min? (21
, 6 cubic feet). A bag of particles to be tested (approximately 6035.2 nf (368 cubic inches)) was inserted into the bedding box through an 8 inch diameter hole in the top of the cover. Pour and use your hands to spread the bedding evenly over the bottom of the bedding box. The hole on the top of the cover was plugged. The sample air sampler was run for 5 minutes on each sample to collect all airborne particles.

To determine the amount of dust collected (taking into account background indoor dust levels), sampler filters were dried overnight and weighed. Trademark [Pidy-Cat 3J 4.536 kg (10 lb) bag of cat bedding (6035, 2n)
? ) of bedding material, approximately 276 g net of dust was collected. On the other hand, for the same volume of particles according to the invention, only about 4 g of dust was collected. The dust level index of the particles according to the invention was therefore 1760 of that of commercial clay bedding. Generally, particles according to the invention will exhibit a dust level index of about 10 or less, preferably about 5 or less as explained above.

9 It should be recognized that the above-described examples, which are given by way of illustration only, are not to be construed as limiting the scope of the invention.

[Brief explanation of drawings]

FIG. 1 is a schematic flow chart showing how to prepare the feedstock used in the method of the invention. FIG. 2 is a schematic flow diagram of one embodiment of the present invention showing the agglomeration, surface compaction, and drying steps of the present invention. FIG. 3 is a schematic flow chart showing steps similar to FIG. 2, but including the additional step of flattening the particles to form platelets. FIG. 4 is a schematic flow chart showing a simplified process for agglomerating particles and partially drying and compacting the surface of the particles using a single rotating drum. FIG. 5 is a photograph showing several representative dry particles of the present invention that are irregular but generally spherical. FIG. 6 is a photograph showing several representative particles of the present invention flattened into platelets. FIG. 7 is a photograph showing a cross section of a typical particle of the present invention. FIG. 8 is a photograph showing a cross-section of representative particles of the present invention formed simply from paper mill sludge. Figure 9 is a photograph of the formulation before the first agglomeration step;
It is a photograph showing the appearance of protruding fibrils and fiber ends. 5... Waste paper, 7... Breaker, 12... Metal detector. 1

Claims (1)

Claims: (1) A compacted outer surface consisting essentially of cohesive fibers, fiber aggregates, and/or fiber particles of fibrous cellulosic material and substantially free of protruding fibrils. A particle characterized by having (2) The particles according to claim (1), characterized in that they have an irregular and substantially spherical shape. (3) Particles according to claim (1), characterized in that they have a platelet shape. (4) The particles according to claim (1), wherein the particles are bonded together substantially only by hydrogen bonds. (5) The particles according to claim 1, having an agglomerate density of about 0.2 g/cJ to about 0.3 g/cJ. (6) The particles according to claim (1), which have a water absorption of 2 g of fishing rod per 1 g of particles. (7) The particles according to claim (1), wherein the fibrous cellulosic material is sludge from a paper mill. (8) The particles according to claim (1), wherein the fibrous cellulose material is waste paper. (9) consisting essentially of fiber-sized pieces of fibrous cellulosic material selected from the group consisting of agglomerated fibers, fiber aggregates, waste paper and tissue mill sludge, and combinations thereof; Particles having a plate-like shape and having a compressed outer surface substantially free of protruding fibrils. (10) Particles according to claim (9), characterized in that the particles are bonded essentially only by hydrogen bonds. (11) The particles according to claim 10, characterized in that they have a dust level index of about 10 or less. (12) Approximately 1/lG inch to approximately 3/8 inch (approximately 0.1
Particles according to claim 11, characterized in that they have a diameter of 5875 cm to about 0.9525 cm. (13) About 0.2 g/cIIl to about 0.3 g/c
Claim No. 1 characterized in that it has an agglomeration density of J and a water absorption of 2 g of fishing per 1 g of particles.
Particles described in section 2). (14) a) a) agglomerating fiber-sized pieces of a wet blend of fibers, fiber aggregates, and/or fibrous cellulosic feedstock to form individual agglomerated particles; and b) compressing the surface of the agglomerated particles. to form a high-density skin substantially free of protruding fibrils, and C) drying the aggregated particles. (15) The manufacturing method according to claim (14), wherein the particles are agglomerated using a rotating disk type aggregation device. (16) The surface of the aggregated particles is compressed by bouncing or rolling the aggregated particles in a fluidized bed supported by upwardly flowing air. Production method. (1,7) a) agglomerating a wet blend of fibers, fiber aggregates, and fiber-sized pieces of fibrous cellulosic feed material to form individual aggregate particles, said wet blend having a particle size of about 75 b) compacting the surface of the particles; C) partially drying the particles to about 30 to about 50% moisture by weight; d) reducing the partially dried particles to a A method for producing cellulose particles, comprising: forming the particles into a plate, and e) drying the particles to a moisture content of about 10% by weight or less. (18) The manufacturing method according to claim (17), wherein the particles are agglomerated using a rotating disk type aggregation device. (19) Claim (18) characterized in that the particles are surface compressed and partially dried in a fluidized bed dryer.
Manufacturing method described in section. (20) Manufacture according to claim (19), characterized in that the partially dried particles are placed on a moving belt and flattened in two pieces between the moving belt and a pressure roll. Method. (21) The manufacturing method according to claim (20), characterized in that the flattened particles are dried in a fluidized bed dryer to a moisture content of about 5% by weight. (22) a bed of particles provided within a container, said particles consisting essentially of aggregated fibers, fiber aggregates, and/or fiber-sized pieces of fibrous cellulosic material;
A bed characterized by having a compressed outer surface substantially free of protruding fibrils. (23) A head according to claim (22), characterized in that the particles have the shape of a small cane. (24) The fibrous cellulosic material is selected from the group consisting of waste paper, paper mill sludge, and a combination of waste paper and paper mill sludge. Bed as described. (25) The bed according to claim 24, wherein the particles have a diameter of about 1/16 inch to about 378 inches (about 0.15875 cm to about 0.9525 cm). 26. The bed of claim 25, wherein the particles further include an antistatic agent in an amount sufficient to reduce the tendency of the particles to stick to -1111 bristles. (27) The bed of claim 25, wherein the particles have a dust level index of about 10 or less.