Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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TITLE OF INVENTION
ABSORBENT MATERIAL
FIELD OF INVENTION
The present invention relates to absorbent materials,
particularly to absorbent materials which are based on
ground paper.
BACKGROUND TO THE INVENTION
Absorbent materials ingranular form are used for
a variety of industrial and household purposes. Typical
uses include the absorption of oil, grease and chemicals on floors
and elsewhere, in animal toilet applications as a cat box
absorbent, as carriers for chemicals, such as, pesticides
and herbicides, in various agricultural and horticultural
application, and as ground cover.
Such materials have heretofore almost exclusively
consisted of absorbent clay granules, such as Fullers earth,
although more recently it has been suggested in U.S. Patent
No. 4,163,674 to utilize gypsum, in the form of Plaster
of Paris, as a base for granular absorbent materials~ The
product is formed in this prior art patent by forming a
paste or slurry of the gypsum, which may also contain addi-
tives, such as finely divided paper, setting and hardening,
and then grinding and crushing the dried material to granular
form.
The granular product produced by this procedure
consists mainly of gypsum and may contain only up to
20% by weight of the gypsum of o~her additives. The formation
of a paste or slurry of the gyps~ll is essential in this
prior art procedure, so that considerable energy is required
to dry the product.
SUMMARY OF INVENTION
In accordance with the present invention, there
is provided a granular and/or fibrous absorbent material which is based
on ground paper and which optionally may contain Plaster
of Paris and/or other fillers and additives. The ratio
of components in the composition depend on the end use
desired for the product, which may include any of those
end uses for which granular absorbent materials have tra-
ditionally been used.
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The product of the invention in its granular form
is produced by a unique procedure wherein a dry mix of
the components of the product is initially formed and then
is granulated by contact with droplets of water. The resulting
product may be used as such or may be dried to a lesser
moisture content, depending on the desired end use.
The product which is provided by this invention
is highly absorbent, typically possessing about 3 to 4
times the absorbency of conventional clay products on a
volume basis. The product is obtained using relatively
inexpensive materials with little or no waste and with a
much decreased energy consumption, when compared with the
product of U.S. Patent No. 4,163,674. The product is bio-
degradable and utilizes a renewable resource.
GENERAL DESCRIPTION OF INVENTION
As mentioned previously, the present invention
essentially requires the use of ground paper material.
Any available source of paper may be used to form the ground
paper, for example, newsprint, cardboard, clay-loaded paper
and office stationary. The ground paper may be provided
into its particulate fibrous form from waste material or
from unused paper material and usually has a particle size
from about 3 mm to about 20 mm.
The utilization of other optional components with
the ground paper depends on the intended use of the end
product. One optional component is Plaster of Paris, i.e.,
the chemical having the forluia CaSO4 ~H2O. Other optional
components include, sand, f~rtilizer, colourants, oil,
deodorizers, and detergents.
The various components in their chosen relative
proportions are dry-mixed to a homogeneous consistency
by any convenient dry mixing technique, for example, utili-
zing a ribbon or screw type mixer. The relative proportions
of the various components depend on the intended end use
35 of the products. The weight ratio of the components ground
paper: Plaster of Paris: other components usually is
in the range of 1:0:0 to 1:2:1. For example, for the forma-
tion of a product useful as a cat box absorbent, a typical
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weight ratio is 1:0.2:trace (with the other component taking
the form of commercially-available deodorant materials).
The dry mixed material may be oil treated to provide
a product which absorbs oil selectively and rejects water.
In this product, the ground paper is in fibrous form. A
detergent may also be incorporated into this product in
varying proportions. Greater quantities of detergent render
the mixture more water-soluble. Greater quantities of oil
render the mixture more oil selective.
The dry mixed material, when not oil treated,
is contacted with discrete droplets of water, which may
also contain a small amount of wetting agents, if desired,
at a controlled rate of application. The water droplets
usually have a diameter in the range of about 0.1 to about
15 5 mm and preferably about l to 2 mm. The application of the
water droplets causes the formation of granular particles
from the dry mixed material.
Usually water is used in a weight ratio to dry
mixed material in the range of about 0.5:1 to about 2:1.
20;Below the weight ratio of 0.5:1, a large percentage of
fluffy dry material remains which must be recycled while,
above the the weight ratio of 2:1, additional water is
wasteful, increases the evaporative load and often leads
to loss of integrity of the granules. Preferably, the
25 weight ratio of water to dry mixed material is about 1.0:1.
The degree of mixing which is applied to the damp
granules which result from the water application step deter-
mines the density and shape of the particles which are
formed. Shorter periods of mixing form lower density plate-
30 like particles, while longer periods of mixing form moredense and sphere-like particles. The density and shape
of product which is formed depends largely on the desired
end use of the product.
The density of product which is produced also
35 is dependent to some extent on the size of droplet in the
water spray, smaller droplets tending to form lighter pro-
ducts while larger droplets tending to form heavier products.
The density of product produced in all cases is
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significantly lighter than clay absorbents, the actual density
varying depending on the intended end use of the product.
Usually, the density varies from about 2 to about 20
lb/cu.ft., products at the lower end of the density scale
being useful as thermal insulation products while products
at the higher end of the density scale are useful as floor
cleaning materials. Products of intermediate to higher
density, such as about 10 to 20 lb/cu.ft. are useful as
animal box absorbents.
The damp granular material resuIting from the
water treatment step may be bagged as such for use as a
garden mulch or as a general ground cover. Alternatively,
the damp granular material may be dried to a lower moisture
level, usually below about 20% by weight and typically
about 10 to about 15 wt.~. The drying operation may be
commenced immediately following completion of the mixing
step, or may be deferred to permit Plaster of Paris, if
present, to be fuIly or partially hydrated. Fully hydrated
Plaster of Paris (i.e., CaSO4.2H2O) is often preferred
when the granular product is to be used for oil absorption
from shop floors and the like while partially hydrated
Plaster of Paris is often preferred when the granular product
is to be used in cat or other animal boxes, since it possesses
sanitizing properties in this form.
The dried granular material is classified, such
as by sieving or by using an air flow separator, to provide
granuIes of a ,ize range desired for the intended end use
of the product. Fines usually are recycled to the dry
mixing step while coarse particles maybe crushed to the
particle size desired for end use or the crushed material
may be recycled to the dry mixing step. The fines also
may be used as filler material in celluIosic insulation.
The essential use of ground paper in the product
of this invention provides a high absorbency of a variety
35 of liquid materials, typically about 3 to 4 times the absor-
bency (as determined by volume pick-up) of clay materials.
At the same time, this substantially increased absorbency
is attained at densities which are considerably less (typic-
ally about l/3rd) than those of clay products. The products
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of the invention maintain a satisfactory granuIar form
in use and do not tend to powder, create dust or otherwise
degrade.
One particularly useful application of the product
of the invention is an absorbent in animal boxes. The
product has a lowPr density and greater absorbency than
existing clay products, and is readily disposed of when
used, in that the product is capable of ready passage through
existing sewer lines of homes and municipalities and is
biodegradable.
As will be seen from the above description of
the invention, the procedure for formation of granular
material does not involve the formation of a slurry in
water and only minimal drying since granules are formed
15 directly in the water application step. This procedure
contrasts with that of U.S. Patent No. 4,163,674. In addition,
the present invention essentially requires the presence
of ground paper, in all cases greater than about 25% by
weight of the final product (on a dry weight basis). In
20:contrast, in the product of U.S. Patent No. 4,163,674,
ground paper is an optional component which is never present
in more than 20% by weight of the product (on a dry weight
basis).
EXAMPLES
Samples of granular product were formed utilizing
varying proportions of ground clay paper (i.e., magazine
stock), Pl.ster of Paris and water. The ground clay paper
of 6 mm mesh size was dry mixed with Plaster of Paris in
a conventional mortar mixer for one minute to form an intim-
ate admixture of the components.
Water droplets of 1 mm size were sprayed onto the
mixture over a period of two minutes to form granuIes.
Mixing was continued for a further two minutes to form
substantially spherical granules. The granuIes were dried
to a moisture content of about 15 wt.% by heating in a
stream of hot air at a temperature of about 60C for about
100 minutes.
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The components of the products which were prepared
are set forth in the follcwing Table I:
TABLE I
Product Components
No.Clay Paper Plaster Water
of
Paris (oz )
1 10 0 17
2 10 1 17
10: 3 10 3 18
4 10 5 20
0 9*
*Note: The water included half a cup of detergent.
The products in each case were tested for density,
15 water absorbency and oil absorbency and compared`with the
properties of proprietary clay product known as "Oil-Dri".
The resuIts of the wa~er absorbency tests are set forth
in Table II while those for the oil absorbency tests are
set forth in Table III:
TABLE II
Water Absorbency Tests
Product Density Quantity Quantity Wt.Ratio of
(lb/ft3) of of ~ter Product:Water
Product Absorbed (Surface Damp
( OZ ) ~Z )Product)
1 10.6 5 10 2: 1
2 10.6 6 10 1.67:1
3 12.2 5 8 1.6:1
4 12.6 8 13 1.6:1
30 Oil-Dri 32.416 8 0.5:1
TABLE III
Oil Absorbency Tests
ProductDensity Quantity Quantity Wt.Ratio of
(lb/ft3) Of of Oil Product:Oil
Product Absorbed(Surface damp
(OZ) (OZ)Product
1 10.6 8 10 1.25:1
2 10.6 8 9 1.12:1
3 12.2 8 8 1:1
4 12.6 8 8 1:1
Oil-Dri 32.416 4 0.25:1
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It will be seen from the results set forth in
Tables II and III that the product of the invention exhibits
considerably greater water and oil absorbency than the
clay-based product and further has a considerably lower
5 density than the clay-based product.
SUMMARY OF DISCLOSURE
In summary of this disclosure, the present invention
provides a novel granular and/or fibrous absorbent material
having a wide variety of end uses and which is based on
ground paper. Modifications are possible within the scope
of this:invéntion.
