Paperboard container for solid block detergents

Disclosed is a container 10, 25 for dispensing of detergents and other solid chemicals, and a method for manufacturing the container 10, 25. The container 10, 25 has a paperboard housing 11, 26 which contains a plastic bladder 21, 27. The exposed surface of the solid chemical is covered by a cap 12, 32. A handle 16, 37 is provided. The container 10, 25 is suitable for use in a dispensing device 40.

FIELD OF THE INVENTION 
This invention relates generally to paperboard containers, and more 
particularly to a paperboard container which is insertable in a dispensing 
apparatus for a solid detergent. 
BACKGROUND OF THE INVENTION 
The utilization of automatic dispensers to dispense chemicals used in 
cleaning processes is well known in the art. Cleaning compositions include 
compounds such as detergents, rinse aids, softeners, bleaches and the like 
employed to clean fabrics, dishes and hard surfaces. 
The cleaning composition may be a solid detergent in several different 
forms, including powder, flakes or granular detergent, and pre-shaped 
detergent briquettes. Another form of solid detergent is the "cast" or 
block form, comprising detergent that is cast within a mold or a 
container. Dispensing systems for these solids are known in the art. See, 
for example, U.S. Pat. No. 4,426,362, issued to Copeland et al. and 
commonly owned U.S. Pat. Nos. 4,569,781 and 4,569,780 issued to Fernholz 
et al. The solid detergent is dispensed by spraying a solvent onto the 
detergent block within the container, thereby dissolving the exposed 
surface of the detergent to form a concentrated working solution. The 
concentrated working solution falls into a reservoir or is directed by a 
conduit to the wash tank of a washing apparatus. When a chemical compound 
within the container is completely utilized, the exhausted container is 
discarded, and a fully charged container is placed in the dispenser. 
Solid chemicals used in cleaning processes are preferably cast in a sturdy 
container which can act as a mold, a shipping and storage container, and a 
dispenser housing. The container may either be retained within the 
dispenser as the chemical is being used, or the chemical may be removed 
from the container and placed into the dispenser. However, hazardous 
chemicals used in cleaning processes such as highly alkaline detergents 
are preferably packaged such that they can be dispensed without coming 
into physical contact with the human body. 
The advent of high performance products, stimulated in part by increased 
aesthetic and sanitary standards and a demand for shorter wash times, has 
generally been characterized by the development of more complex detergent 
compositions which are more hazardous to the user, less stable, and more 
difficult to dissolve in a satisfactorily uniform manner. Chemicals used 
in high performance products, particularly for hard surface cleaning (e.g. 
ware washing), include alkali metal hydroxides (e.g. sodium hydroxide), 
phosphates, silicates, chlorine-containing compounds, defoamers and 
organic polyelectrolyte polymers. 
Utilization of solid cleaning compositions has several advantages over the 
use of pre-mixed liquid cleaning compositions. These advantages include 
the fact that the solid detergent is easier and cheaper to ship due to its 
greatly-reduced weight; the solid detergent requires less storage space; 
and the solid detergent improves the safety of the work environment by 
reducing possible splashing of hazardous chemicals. Overall, the solid 
detergent is more convenient for the user, and it permits easy transfer 
from a container to a dispenser, involving no pouring, spilling or 
leftover product. 
In the past, the containers for the solid detergents have been made 
entirely of a molded plastic material such as polyethylene or 
polypropylene. The containers are filled with detergent, stored, shipped 
to the point of use, and placed into a dispenser. The containers are 
subjected to extreme conditions such as high moisture, extremely high and 
low temperatures, and corrosive chemicals. The plastic containers are used 
only a single time, and then are often discarded to a landfill. These 
plastic containers sometimes are recycled, but they typically cannot be 
stacked or collapsed to a compact or flat form. 
SUMMARY OF THE INVENTION 
The present invention is a detergent-containing article of commerce, 
comprising a bladder made of a plastic material; a solid chemical within 
the bladder such as a detergent; a paperboard housing surrounding the 
bladder; and a cap which is removably attached to the housing. In the 
preferred embodiment, the exposed surface of the detergent has a 
water-soluble coating. Additionally, one end of the container has a 
handle. The bladder and housing are attached such that they can be 
separated from each other after the container has been used. 
Another aspect of the invention is a method for manufacturing the 
container. This method comprises the steps of: attaching a bladder within 
a paperboard housing, filling the bladder with detergent or other solid 
chemical, applying a water-soluble coating to the eroding surface of the 
detergent, and affixing a cap to the housing so as to cover the eroding 
surface of the detergent. 
A particular advantage of the present invention is that the container can 
be disposed of in an environmentally sound manner. The container of the 
present invention has less plastic than prior containers employed for 
similar purposes. Portions of the package are recyclable. The container's 
bladder can be made from recycled polymers such as polyethylene, or water 
dispersible polymers, such as polyvinyl alcohol or ethylene acrylic acid. 
The paperboard components of the package are separable from the recyclable 
portions of the package so that these two components can be sent to 
different destinations after the container has been used. Furthermore, the 
package can be crushed into a compact configuration after use, thereby 
reducing space requirements for the user. 
Another advantage of the container is that the container can be fabricated, 
filled with the detergent, stored in a warehouse, and shipped to the 
intended destination in a simple and efficient manner. The invention 
reduces storage and handling requirements, because the housing walls, 
bottom disks and top closures can be shipped flat. The bladders can be 
nested. As a result, a minimal amount of storage space is necessary. This 
results in cost savings for the manufacturer, and reduces labor and space 
requirements. The finished containers are stackable and weigh less than 
conventional containers. 
Yet another advantage of the present invention is that the container is 
able to be filled with highly corrosive detergent products. The container 
maintains its structural integrity throughout the storage, shipping and 
dispensing steps, and there is no leakage which could expose the user to 
potentially hazardous chemicals. Even if the outer paperboard housing were 
to tear or be damaged, the detergent product would still be contained 
within an interior bladder. Also, the detergent does not come in contact 
with the user because of the container's design and because of the 
presence of a water soluble coating on the detergent's exposed surface. 
Yet another advantage of the present invention is that it can be utilized 
with conventional dispensing apparatus which have in the past utilized 
plastic containers. Thus, no retrofitting or replacement of the relatively 
expensive dispensing equipment is necessary in order to use the containers 
of the present invention. 
These features, along with other advantages, will become subsequently 
apparent, based on the details of construction and operation as more fully 
described hereinafter, reference being made to the accompanying drawings, 
wherein like numerals refer to like parts throughout.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
A first embodiment of the container 10 for solid chemicals is illustrated 
in FIGS. 1-3 and 7. The container 10 serves as a mold for the solid 
detergent, a shipping and storage container, and a housing for the 
detergent while it is being dispensed. The container 10, as positioned 
within a dispensing device 40, is illustrated in FIG. 7. The container 10 
is inverted and placed in a detergent dispenser reservoir 44. Water from a 
conduit 45 enters the dispensing device 40, and is directed toward spray 
means (such as a spray nozzle) within the dispenser 40. An 
upwardly-directed water spray dissolves the detergent from the container 
10 in an amount as needed. The dissolving apparatus 40 need not be 
physically removed from the washing machine. Indeed, it is a common 
practice to mount dissolving/dispensing devices 40 directly above--or on 
the side wall of--the wash tank of the cleaning machine. 
The container 10 has a housing 11 which has a cylindrical side wall 41 and 
bottom end member or disk 14. The side wall 41 and disk 14 of the housing 
11 are made of a paperboard material. In the preferred embodiment, a 
plastic film or coating (not shown) is applied to both the outer and inner 
surfaces of the housing 11. Alternatively, the film could be applied to 
either the inside surface or the outside surface. The coating is 
preferably made of a polyethylene material, and it is applied to the 
paperboard with either a laminating or cascading process. The film 
provides additional stability and durability to the container 10 by 
protecting the container 10 from excessive moisture. 
The container 10 has a cap 12 on the top end 38 of the housing 11. The cap 
12 has a circular shape, with an optional raised center portion 13 for a 
label or graphics, surrounded by one or more annular ledge portions 33. 
The raised portion 13 and ledge portion(s) 33 facilitate stacking of 
several containers 10. The cap 12 has an annular lip 14 which is slightly 
larger than the size of the housing 11, so that the cap 12 can be snap-fit 
into place on the housing 11. Instead of a snap-fit cap, the cap 12 could 
be removably attached to the housing 11 in other ways, such as by 
utilizing a tearaway strip (not shown). 
FIG. 2 illustrates a bottom view of the housing 11, i.e., the end opposite 
the cap 12. The end wall or disk 14 is preferably adhered to the side wall 
41 of the housing 11 by a suitable adhesive. Suitable adhesives include 
poly (vinyl alcohol-acetate) blends, dextrin, animal glue, polyethylene, 
and hot melts. The paperboard of the side wall 41 is folded over and 
crimped, so as to form a pleated border 15 around the edge of the disk 14. 
In this manner, the outer periphery of the disk 14 is sealed to the inner 
periphery of the housing 11. The disk 14 is preferably made of paperboard, 
and the disk 14 may or may not have a plastic coating on one or both 
sides. Preferably, the paperboard material for the disk 14 contains a wet 
strength additive. This additive prevents degradation of the container 10 
due to exposure to water or chemicals. 
A handle 16 may be formed in the disk 14. Preferably, a pair of curved 
score lines 19 in the disk 14 enable the user to tear away and fold a pair 
of flaps 20 inwardly. This forms a pair of semi-circular finger holes 17 
separated by a bridge 18. As shown in FIG. 3, the flaps 20 extend into the 
interior of the housing 11. The holes 17 allow the user's thumb and finger 
to be inserted in the opposite hollows of the handle 16 to permit ease of 
holding and removal of the container 10 from the dispenser housing 40. 
As shown in the exploded view of FIG. 3, there is a bladder or liner 21 
which is insertable within the housing 11. The bladder 21 has a 
cylindrical side wall, a first closed end 22, and an opposite open end 23. 
The bladder 21 has a lip 34 which fits over the rim 24 of the housing 11. 
Preferably, the lip 23 is attached to the rim 24 with a ring of hot-melt 
adhesive. Alternatively, a heat-sealing process could be used to adhere 
the bladder 21 to the housing 11. 
The liner 21 is made of a lightweight plastic material, preferably 
low-density, medium-density, or high-density polyethylene or 
polypropylene. Other resins such as PET (polyethylene terephthalate) or 
polyvinyl chloride could also be used. The bladder 21 can be manufactured 
using a thermoforming, injection-molding or blow-molding process. The 
liner 21 is made of either a semi-rigid or flexible material. 
In the preferred embodiment, the liner's side wall has a ring 35 proximate 
its upper end. The upper portion of the liner's side wall (above the ring 
35) has a slightly larger diameter than the remainder of the liner's side 
wall, thus forming the ledge or ring 35. The rings 35 facilitate the 
stacking or nesting of many liners 21 before the liners 21 are filled with 
the detergent during the manufacturing process. 
The detergent composition is normally formed by mixing and heating the 
composition in an aqueous solution, thickening the solution and preferably 
also cooling it, pouring the solution into the bladder 21 which serves as 
a mold, and allowing the mixture to solidify. The cast detergent 
composition is preferably left in the bladder 21 during the dispensing 
process. Alternatively, the detergent block could be popped out of the 
bladder 21 onto a screen in the dispensing device 40. The detergent may 
have a wide variety of applications, such as rinse aids, softeners, 
bleaches, and cleaning compositions for cleaning fabrics, dishes and/or 
hard surfaces. An eroding surface of the solid detergent is proximate the 
open end 23 of the bladder 21. As used in the claims, the term "eroding 
surface" is the detergent surface's position when the article 10, 25 is 
full. It is to be understood that the position of the eroding surface will 
change as the detergent level recedes. 
In the preferred embodiment, a water-soluble coating is poured or sprayed 
onto the exposed surface of the detergent. This coating or membrane seal 
increases the stability of the detergent and provides safety for the user 
by preventing contact with the highly alkaline, caustic detergent. The 
barrier coating substantially covers the surface of the detergent mass and 
prevents the absorption of environmental water from the atmosphere into 
the surface of the detergent mass. That is, the water soluble covering 
protects the hands of the person who handles the container 10. The 
water-soluble film may be of polyvinylalcohol, or of the type described in 
U.S. Pat. No. 5,316,688 to Gladfelter et al. 
The coating comprises a continuous layer covering substantially the entire 
exposed face of the detergent mass. The coating preferably has a thickness 
of about 0.1 to 12 millimeters, most preferably about 0.5 to 3 
millimeters. The coating should be chemically stable with respect to the 
chemical constituents of the detergent mass. The coating can be introduced 
onto the detergent mass using any conventional coating technique such as 
coextrusion, spray coating, curtain coating, immersion, surface molding 
and others. Combinations of coating processes can also be used to ensure 
that a complete coating is formed. For example, an initial coating can be 
coextruded surrounding an extruded detergent mass core. Such a process 
would leave open, uncoated ends on the detergent mass. Such an article can 
be further coated using spraying, curtain coating, etc. to seal the ends. 
Coating compositions can comprise materials that are applied in the form of 
liquids. Such liquids can be room temperature solids that can be applied 
in the form of a heated melt or in the form of a solvent-based solution or 
dispersion. Such dispersions could be made using water as a liquid base or 
using other solvents such as ethanol, methanol, propanol, petroleum ether, 
benzene toluene, etc. Preferably solvent-based materials are applied in 
the form of aqueous dispersions for reasons of cost and safety. Preferred 
dispersion materials can be sprayed or otherwise coated on the detergent 
mass, leaving a coating after the aqueous or other vehicle has evaporated. 
Such dispersions preferably comprise 10-80 wt-% solids, the balance being 
water stabilizers and other functional ingredients. The dispersion should 
have a viscosity that permits ease of coating but should maintain 
sufficient solids to rapidly coat the detergent mass. Suitable dispersions 
for use in the coatings of the composition include 
poly(ethylene-co-vinylacetate), poly(ethylene-co-acrylic acid), 
poly(ethylene-co-methylacrylate), acrylic homopolymers such as polyacrylic 
acid, polymethacrylic acid, polymethylmethacrylate, 
styrene-butadiene-styrene copolymers, styrene-acrylic copolymers. 
The coatings can also be applied in the form of an aqueous solution of 
materials. Soluble materials can include soluble polymeric materials such 
as soluble surfactants, soluble cellulosic materials, soluble salts, etc. 
Examples of such materials include polyethylene glycol (polyethylene 
oxide), polyethylene oxide, polypropylene oxide, block copolymers, 
polyacrylic acid, etc. 
The water-soluble coating could also be applied in the form of a melt 
material. Such materials are commonly substantially organic compositions 
having a melting point greater than about 30.degree. C., preferably about 
35.degree.-55.degree. C., have a melt viscosity that can obtain a 
continuous, uniform coating at about 30.degree.-60.degree. C., can and are 
stable to the presence of the alkaline materials in the detergent mass. 
Among the useful coatings include waxy materials. Such waxes include low 
molecular weight (e.g. 1000-6000 molecular weight) polyethylenes having a 
softening point of about 66.degree. to about 150.degree. C., petroleum 
waxes such as paraffin wax having a melting point of from about 60.degree. 
to about 100.degree. C., microcrystalline wax having a melting point from 
about 60.degree. to about 100.degree. C., and synthetic waxes made by 
polymerizing carbon monoxide and hydrogen such as Fisher-Tropsch wax. 
Further, hydrogenated animal or vegetable fats or oils can also be used for 
the water-soluble coating if they possess the appropriate melting points 
and melt viscosity. Such oils include lard, hydrogenated soy bean oil, 
hydrogenated cotton seed oil, and hydrogenated castor oil. Further, 
hydrogenated fatty acids obtained from the oils discussed above can also 
be used as coating materials. Further derivatives of the fatty acids set 
forth above can be used as coating materials. Preferred fatty acid 
derivatives include fatty acid amides made by reacting the fatty acid with 
nitrogen bases. Preferred nitrogen bases include ammonia and an amine. 
Preferred amines include methyl amine, dimethyl amine, ethyl amine diethyl 
amine, monoethanol amine, diethanol amine, and other reactive amines 
providing at least one active hydrogen on the amine nitrogen for reaction 
with the fatty acid carboxylic acid group. Preferred coating materials for 
use in a melt coating composition of the invention include hydrogenated 
and non-hydrogenated coco fatty acid, hydrogenated and non-hydrogenated 
stearic acid, hydrogenated and non-hydrogenated stearic acid monoethanol 
amide, hydrogenated and non-hydrogenated stearic acid diethanol amide, 
paraffin wax, polyethylene glycol having a molecular weight ranging from 
about 1000 to 10,000, pluronic block copolymers comprising at least one 
polyethylene oxide block and at least one polypropylene oxide block having 
molecular weights of about 1000 to 10,000. 
The coating composition formed on the detergent mass can comprise a single 
layer comprising the organic material. Further, the coating can comprise a 
single layer of organic material with inorganic materials used as diluents 
or as materials that can promote the solubility or other removal of the 
coating. Such organic coatings can contain as an inorganic component, 
sodium chloride, sodium sulfate, sodium carbonate, sodium acetate, sodium 
metasilicate, sodium phosphate, trisodium phosphate, trisodium 
polyphosphate, sodium acrylic polymers and others. The organic coatings 
that optionally can contain some proportion of inorganic material can also 
be used with other coating layers. The organic coating can be formed over 
a wholly inorganic coating comprising materials discussed above or can be 
used with a separate distinct organic coating as discussed above. When the 
container 10 is in place in the dispensing device 40, the coating or seal 
automatically dissolves upon being sprayed with water. 
To manufacture the first embodiment of the container 10, a long paperboard 
blank is formed around a mandrel and heat sealed at the side seam. A 
plastic coating and any desired graphics have been applied prior to this 
forming process. The plastic coating applied to the inner and/or outer 
surface of the paperboard acts as the adhesive when activated by high 
temperature heaters. The circular disk 14 is placed in the tube 11 and 
sealed to the sidewalls 41 of the container 10. The bladder 21 is 
preferably made by a thermoforming process. A ring of hot-melt adhesive is 
applied to the bottom disk 14, and the bladder 21 is inserted within the 
housing 11 so as to adhere the bottom of the bladder 22 to the disk 14. 
The bladder's rim 34 is heat sealed to the rim 24 of the housing 11. The 
bladder 21 is then filled with the molten detergent, which is allowed to 
cool and solidify. The water soluble membrane or coating (not shown) is 
poured or sprayed onto the exposed surface of the detergent. The lid 12 is 
then snap-fit into place. 
The second embodiment of the container is illustrated generally at 25 in 
FIGS. 4-6. This embodiment has a housing 26, a bladder 27, and a cap 32. 
The second embodiment 25 is also suitable for use with the dispensing 
device 40 as shown in FIG. 7. With each embodiment, the housing 11, 26 is 
approximately 6.5 inches (16.5 centimeters) in diameter and 5.5 inches 
(14.0 centimeters) in length. The bladder 27 is made of any suitable 
material that is capable of withstanding exposure to highly caustic 
detergent. The bladder 27 has a ring 56 to facilitate nesting. 
With the design illustrated, the housing 26 is produced by a spiral winding 
method. A web of paperboard and a web of label are treated with adhesive 
and wound continuously on a reciprocating mandrel. The resulting tube is 
trimmed to the appropriate length according to the desired size of the 
housing 26. The seam lines 29 of the housing 26 are held in abutment by 
heat sealing. 
Alternatively a convolute process may be used to form the housing 26, 
wherein the paperboard blank is coated with adhesive and entered onto a 
turning mandrel in a discontinuous process. The blank may be precut to the 
desired length before being entered onto the mandrel, or the cutting may 
be done after a long tube has been formed. 
The tube or housing 26 has a first, open end 30, which remains open during 
use of the container; and a second, open end 31 which is covered with a 
removable cap 32. The cap 32 is similar to the cap 12 of the first 
embodiment. (There is no end member on the second embodiment of the 
container 25 which is similar to the disk 14 on the first embodiment of 
the container 10). 
In the container's second embodiment, the bottom end 33 of the liner 27 may 
have a handle 37. Preferably, the handle 37 is integral with the bladder's 
body and molded as a single piece. The handle 37 is preferably formed as a 
longitudinal rib which extends outwardly from the end surface of the 
bladder 27. The user can position a thumb and finger(s) on each side of 
the rib in order to easily hold the container 25, and to insert and remove 
the container 25 from the dispenser housing 40. 
Although the housings 11, 26 are illustrated as being cylindrical, they 
could have a rectangular, oval, or other shape, so long as the housing 11, 
26 is able to fit securedly in the dispensing apparatus 40. 
Although the first end 38, 31 of each container 10, 25 is shown as being 
completely open across its entire width, it is possible for the first end 
38, 31 to have an annular end member with a central aperture (not shown). 
The annular end member could be flat or funnel-shaped. The aperture in the 
end member would permit passage of the water spray to the detergent's 
exposed face and the dispensing of the use solution. 
To manufacture the second embodiment of the container 25, the paperboard is 
wrapped on a mandrel. The paperboard may be precut before being wrapped on 
the mandrel, or the cutting step may be performed at a later point. The 
tube edges are heat sealed to form the seam lines 29 of the housing. Any 
desired labels are applied to the tube. The label (not shown) may be made 
of coated papers, foil/kraft laminates and film constructions based on 
polyethylene or polypropylene. A label may also be applied to the raised 
surface 28 of the cap 32. The bladder 27 is preferably made by 
thermoforming process. A ring of hot-melt adhesive is applied to the rim 
39 of the housing 26, and the bladder 27 is inserted within the housing 26 
so that the bladder's lip 55 fits over the rim 39. (Alternatively, the lip 
55 of the liner 27 may be heat-sealed to the rim 39 of the housing 26). 
The bladder 27 is then filled with the molten detergent which is allowed 
to cool and solidify. The water soluble membrane or coating is applied to 
the exposed surface of the detergent, and the lid 32 is snap-fit into 
place. 
In operation of either of the embodiments 10, 25 of the container, the cap 
12, 32 is removed, and the container 10, 25 is inverted and placed within 
the dispensing device 40. The operator uses the handle 17, 37 to lower the 
container 10, 25 into the dispensing device 40. 
After the operator has lowered the lid 46 of the dispensing device 40 into 
position, then water enters the dispensing device 40 through the water 
inlet conduit 45. An upwardly-directed water spray dissolves the 
water-soluble coating which is on the exposed face of the detergent. The 
water spray also dissolves the exposed face of the solid detergent to form 
a use solution. When the detergent has been exhausted from the container 
10, 25, the operator removes the empty container 10, 25 and replaces it in 
the dispensing device 40 with a full container. The operator can separate 
the bladder 21, 27 from the rest of the container 10, 25 by simply pulling 
the bladder 21, 27 out of the container 10, 25. The housing 11, 26 can 
then be disposed of in a suitable manner, while the bladder 25, 27 can be 
recycled. 
While two preferred embodiments of the invention have been shown and 
described, it should be apparent that many modifications can be made 
without departing from the spirit and scope of the invention. Accordingly, 
the invention is not limited by the foregoing description, but is only 
limited by the scope of the claims.