U.S. patent number 3,762,454 [Application Number 05/198,575] was granted by the patent office on 1973-10-02 for disposable garbage container.
Invention is credited to Roy A. Wilkins, Jr..
United States Patent |
3,762,454 |
Wilkins, Jr. |
October 2, 1973 |
**Please see images for:
( Certificate of Correction ) ** |
DISPOSABLE GARBAGE CONTAINER
Abstract
A disposable garbage container is provided which will degrade in
situ in a garbage dump. The container is made of a plastic film,
e.g., a polyvinyl alcohol plastic film which will dissolve in the
presence of moisture at temperatures of at least about
100.degree.F. One embodiment of the invention includes a degradable
garbage container made of a plastic sheet material which comprises
a laminate or a mixture of cold water soluble polyvinyl alcohol and
hot water soluble polyvinyl alcohol.
Inventors: |
Wilkins, Jr.; Roy A.
(Arlington, TX) |
Family
ID: |
22733956 |
Appl.
No.: |
05/198,575 |
Filed: |
November 15, 1971 |
Current U.S.
Class: |
383/1; 383/116;
428/448; 428/913; 405/129.45; 405/129.1; 220/DIG.30; 428/2;
428/500 |
Current CPC
Class: |
B09B
1/00 (20130101); B65F 1/0006 (20130101); C08L
29/04 (20130101); B65D 65/46 (20130101); Y10S
428/913 (20130101); Y10S 220/30 (20130101); Y10T
428/31855 (20150401) |
Current International
Class: |
C08L
29/00 (20060101); B65D 65/46 (20060101); B65F
1/00 (20060101); C08L 29/04 (20060101); B09B
1/00 (20060101); B65f 001/14 (); B32b 005/16 () |
Field of
Search: |
;61/53.66
;161/DIG.5,410,162,168,166 ;150/1 ;220/DIG.30 ;229/3.5R
;117/16,138.8PV |
References Cited
[Referenced By]
U.S. Patent Documents
Other References
Davidson & Sittig, "Water Soluble Resins," 2nd Ed. Reinhold
Book Corp., N.Y., 1968, pp. 109-115, & 123. (Article by Argana
et al.)..
|
Primary Examiner: Lesmes; George F.
Assistant Examiner: Lipsey; Charles E.
Claims
I claim:
1. A flexible garbage container comprising a receptacle having a
closable inlet, said receptacle made of film which comprises hot
water soluble film, and having microencapsulated liquid container
within rupturable microspheres maintained in a fixed contact with
said film, said microencapsulated liquid consisting essentially of
water or an aqueous solution of bacteria which will degrade the
polymer film and being in contact with said film in sufficient
quantities to dissolve said film in contact with said microspheres
when said microspheres are ruptured and said container is heated to
a temperature sufficient to solubilize said film.
2. The flexible garbage container of claim 1 wherein said
microspheres are dispersed within said film.
3. The flexible garbage container of claim 1 wherein said
microspheres are implanted on the surface of said film.
4. The flexible garbage container of claim 1 comprising a tubular
member having opposed sidewalls and sealed at one end and having
said closable inlet at the opposite end thereof.
5. The flexible garbage container of claim 4 wherein said sidewalls
are coated with said microspheres.
6. The flexible garbage container of claim 4 wherein the middle
sidewall portions of said container are coated with
microspheres.
7. The flexible garbage container of claim 4 wherein the lower
sidewall portions of said container are coated with said
microspheres.
8. A flexible garbage container comprising a receptacle having a
closable inlet, said receptacle made of a hot water soluble polymer
film which is water soluble at temperatures of at least about
100.degree.F, and having microencapsulated liquid contained within
rupturable microspheres maintained in fixed contact with said film,
said microencapsulated liquid consisting essentially of water or an
aqueous solution of bacteria which will degrade the polymer film
and being in contact with said film in sufficient quantities to
dissolve said film in contact with said microspheres when said
microspheres are ruptured and said container is heated to at least
about 100.degree.F.
9. The flexible garbage container of claim 8 wherein said hot water
soluble film is polyvinyl alcohol which is at least 98 percent
hydrolyzed.
10. The flexible garbage container of claim 8 wherein said
microspheres are dispersed within said film.
11. The flexible garbage container of claim 8 wherein said
microspheres are implanted on the surface of said film.
12. The flexible garbage container of claim 8 comprising a tubular
member having opposed sidewalls and sealed at one end and having
said closable inlet at the opposite end thereof.
13. The flexible garbage container of claim 12 wherein said
sidewalls are coated with said microspheres.
14. The flexible garbage container of claim 12 wherein the middle
sidewall portions of said container are coated with said
microspheres.
15. The flexible garbage container of claim 12 wherein the lower
sidewall portions of said container are coated with said
microspheres.
Description
This invention relates to disposable containers. In another aspect,
this invention relates to a disposable garbage container which will
degrade in the presence of water and increased temperature.
The increases in population and industry in metropolitan areas have
resulted in corresponding increases in environmental pollution. A
particularly troublesome problem which most cities in the world are
facing is the adequate disposal of solid waste material such as
household garbage. Most areas are still trying to solve the problem
of what to do with mounting piles of solid waste materials which
have been allowed to stagnate over the years. In addition to this,
is the problem of the proper disposal of currently generated solid
waste materials from homes, offices, and factories.
It is estimated that more than 90 percent of all collected solid
waste material ends up in open dump and landfill disposal
sites.
Cities have been perplexed with the problems of both collecting and
disposing of this solid garbage. The practice of directly
depositing garbage into conventional trash cans has resulted in
unsanitary and littered areas, as well as much difficulty in
garbage collection. As a result, many cities have instigated
ordinances requiring each patron of the garbage system to enclose
solid waste and household garbage materials within plastic garbage
bags. These garbage bags are then collected and transferred to the
disposal areas.
While this legislation has resulted in more sanitary conditions
during garbage pickup and delivery to the disposal area, it has
created problems because the plastic garbage bags add to the
mounting piles of nondecomposable garbage rubble and hasten the
occupation of the available landfill areas. In addition, other
problems have been caused by the use of plastic garbage bags. For
example, landfills containing numerous enclosed polyethylene bags
containing household garbage and the like, have actually exploded
due to the buildup of gas pressure caused by the natural
decomposition of the garbage within the polyethylene bags.
Thus, while the use of the plastic garbage bag has imparted many
beneficial factors in the garbage disposal system, it has also
created many problems which contribute to our environmental
pollution problems.
Therefore, one object of this invention is to provide a novel
garbage container.
Another object of this invention is to provide a novel garbage
container which will degrade in situ in a garbage dump and leave no
polluting residue.
A further object of this invention is to provide novel disposable
garbage containers which will degrade in situ in water disposal
areas and in landfill disposal areas to yield no polluting
residue.
According to one embodiment of this invention, a novel garbage
container is provided which comprises a receptacle having a
closable inlet, and is made of a thin plastic sheet material which
is water soluble at temperatures of at least about 100.degree.F.
The preferred plastic material is a polyvinyl alcohol which is at
least 98 percent hydrolyzed.
According to another embodiment of this invention, a novel garbage
container is provided which comprises a receptacle with a closable
inlet, and is made of thin plastic sheet material which comprises
either a mixture or a laminate of a cold water soluble polyvinyl
alcohol and a hot water soluble polyvinyl alcohol.
According to still another embodiment of this invention, the
sidewalls of disposable garbage container of this invention carry
microcapsules of liquid. The microcapsules contain liquid such as
water, perfume, disinfectants, aqueous solutions of bacteria which
will degrade the polymer film, and the like. Rupturing of the
microcapsules results in sufficient moisture and/or bacteria to
degrade the container, or the release of other desirable material
such as perfume.
This invention can be more easily understood from a study of the
drawings in which:
FIG. 1 is a perspective view of a preferred garbage container of
the subject invention;
FIG. 2 is a schematic view showing the garbage container of the
subject invention degrading in situ in a landfill;
FIG. 3 is a partial sectional view of a sidewall of a garbage
container of the subject invention having a laminated
structure;
FIG. 4 is a partial sectional view of the sidewall of a garbage
container of the subject invention having fiber reinforcement;
and
FIG. 5 is a partial sectional view of a sidewall of a garbage
container of the subject invention which carries microcapsules of
liquid thereon.
Now referring to the drawings and in particular to FIG. 1, a
preferred form of the disposable garbage container of the subject
invention is illustrated in perspective. As shown, container 10
comprises a plastic tube infolded at areas 12, and sealed along
bottom 14 thereof to yield a receptacle having a closable inlet
16.
Container 10 is formed of a plastic sheet material which is soluble
in water at a temperature of at least about 100.degree.F, and
preferably is soluble at a temperature within the range of from
about 100.degree.F to about 140.degree.F. The preferred sheet
material used in container 10 is a polyvinyl alcohol. It is to be
noted that other polymeric materials which are soluble in water at
a temperature of at least about 100.degree.F can be used as
construction material for container 10. However, this embodiment
will be described in relation to the preferred container 10 used in
the scope of this invention which is made of polyvinyl alcohol
sheet material.
The polyvinyl alcohol sheet material used in this embodiment is a
conventional polyvinyl alcohol which is derived from the process of
hydrolyzing at least about 98 mole percent of the acetate groups of
polyvinyl acetate. Thus, as used in the scope of this invention the
terms "percent hydrolysis" or "percent hydrolyzed" shall mean the
mole percent of the acetate groups of polyvinyl acetates which have
been hydrolyzed and thereby replaced by hydroxyl groups. Therefore,
a 98 percent hydrolyzed polyvinyl alcohol is understood to mean
polyvinyl acetate which has been hydrolyzed to the extent that 98
mole percent of the acetate groups have been replaced by hydroxyl
groups.
The molecular weight of the polyvinyl alcohol to be used in the
scope of this invention need only be sufficient to yield a polymer
which is formable into a thin plastic film of at least about 1 mil
and generally from 1 to 3 mils in thickness. Generally, it is
preferred that the polyvinyl alcohol which is used in the scope of
this invention have a viscosity of at least about 25 centipoises
when measured in a 4 percent aqueous solution of the polymer at
20.degree.C by any conventional technique such as the Hoeppler
falling ball method or other techniques, such as with a Brookfield
viscometer, LVF (No. 1 spindle - 60 rpm - 20.degree.C). Generally,
any polyvinyl alcohol which is hydrolyzed from about 98-100 percent
and has a viscosity of from about 25 to about 135 centipoises
measured in a 4 percent aqueous solution at 20.degree.C can be
utilized in the scope of this embodiment of the subject invention.
Such material will hereinafter be referred to as "hot water soluble
polyvinyl alcohol."
It is genrally preferred that container 10 have a wall thickness of
from about 1 to 3 mils. The resulting container is relatively high
tensile strength and tear-resistance, and is insoluble in cold
water.
The polyvinyl alcohol film can be formed into a suitable tube in
the manufacture of container 10 by conventional methods such as
extrusion. Thus, container 10 can be manufactured by longitudinally
infolding opposed regions of an extruded tube, sequentially
severing the infolded tube to obtain a number of tube segments, and
heat sealing one open end of each tube segment. Alternately, a
suitable container can be formed by folding a sheet of polyvinyl
alcohol in half and sealing such as by heat sealing edges of the
open side and one end of the resulting folded material to yield a
container comprising a receptacle with a closable end. Any other
suitably shaped container configuration can be used in the scope of
this invention. Other methods of forming the polyvinyl alcohol film
can be utilized as desired, such as by casting the film from water
solutions of the polyvinyl alcohol.
It is to be understood that minor quantities of materials such as
plasticizers, deodorants, colorants, and the like can be present in
the polyvinyl alcohol film. Examples of suitable plasticizers
include high boiling water soluble organic compounds containing
hydroxyl, amide, or amino groups; glycerine; ethylene; glycol; low
molecular weight polyoxyethylene glycol; sorbitol; formamide; and
urea. Suitable colorants include conventional pigments and dyes.
Filler materials such as clay and calcium carbonate and the like
can also be present in the film. A suitable bactericide includes
hexachlorophene. Other such conventional materials can be utilized
in minor quantities in the polyvinyl alcohol film. In addition, for
heavy duty operations, the polyvinyl alcohol film can contain
reinforcing fibers, preferably cellulose fibers or polyvinyl
acetate fibers. The fibers can be randomly dispersed within the
polyvinyl alcohol film, or can comprise a knitted network which is
encapsulated with polyvinyl alcohol.
Examples of suitable commercially available polyvinyl alcohols
which can be used to form the plastic sheet material for container
10 of the subject invention include the polyvinyl alcohols
manufactured by Du Pont de Nemours and sold under the trademark of
"ELVANOL." Specific suitable ELVANOL materials include ELVANOL
72-60, and ELVANOL 71-30. Other suitable commercially available
polyvinyl alcohols which can be used to form container 10 of the
subject invention are manufactured by Air Reduction Chemical &
Carbide Company of New York, N.Y. and sold under the trademark of
"VINOL." Specific compounds include VINOL 125 and VINOL 165.
Examples of other suitable commercially available "hot" water
soluble materials (soluble at a temperature of at least about
100.degree.F) which can be used in the scope of this invention as
the construction material for container 10 include the polyethylene
oxides sold under the trademark of WSR N-80 and WSR N-10 by Union
Carbide.
In use, container 10 is filled with disposable solid material, for
example, household garbage, and then inlet 16 is closed by suitable
means such as tie wire 18 (FIG. 2). The enclosed container can then
be deposited within an earthen excavation at an appropriate garbage
dump area and covered with earth in the conventional manner.
Preferably, before the garbage is covered, the bags of the subject
invention are lightly sprayed with water. The temperature of the
decomposing garbage within enclosed container 10 in such a landfill
will heat container 10 to a temperature well above 100.degree.F.
This increased temperature together with moisture within the
landfill as well as the moisture generated on the interior of the
bag, which condenses on the inside wall thereof due to the
decomposition of the garbage material, will dissolve portions 20 of
the sidewalls of container 10, as illustrated in FIG. 2. This
degradation of portions 20 of the sidewalls of container 10 will
cause the decomposing garbage to flow normally from container 10
and will allow gases formed in the decomposition of the garbage to
be released from container 10 and slowly diffuse into the soil. The
dissolved polyvinyl alcohol will remain in aqueous solution, and
the resulting aqueous solution is nondeleterious to the
environment. In addition, the resulting polyvinyl alcohol is
biodegradable by common bacteria in garbage fill. Tests show that
such polyvinyl alcohol has a very low biochemical oxygen demand
during decomposition. Container 10 will finally become totally
degraded in the garbage fill and will thereby not contribute to the
residual indestructible solid waste material which is ever present
in garbage landfill areas.
According to another embodiment of the subject invention, a
degradable garbage container is provided which is suitable for sea
disposal in that portions of the bag will degrade in relatively
cold water to release the contents of the bag in the disposal area.
As is well known, many cities around seaport areas dispose of solid
waste material in ocean dumping grounds. The use of conventional
plastic garbage bags in these areas for containing solid waste
material such as household garbage, is undesirable because such
bags have a tendency to float due to entrapped air. In addition,
the plastic material is nondegradable by the seawater and
constitutes an added source of ocean pollution. In accordance with
this embodiment of the subject invention, a plastic garbage
container which can have a similar configuration to that of
container 10 is made from a plastic film material which is composed
of a mixture of cold water soluble polymeric material and a
non-cold water soluble polymeric material. Examples of suitable
cold water soluble polymeric materials which can be used in the
scope of this invention include methyl cellulose, hydroxy
cellulose, hydroxypropyl cellulose, starch, polyvinyl alcohol, and
the like. Examples of suitable non-cold water soluble polymeric
materials which can be used in the scope of this invention include
the above-described "hot water soluble polyvinyl alcohols" and
polyethylene oxides.
The preferred cold water soluble polymeric materials are polyvinyl
alcohols which are less than 98 percent hydrolyzed and will
completely dissolve in water at temperatures less than about
100.degree.F, e.g., about 70.degree.F. Preferably, the cold water
soluble polyvinyl alcohol for use in this embodiment is from 87 to
about 89 percent hydrolyzed; however, polyvinyl alcohols with both
lower and higher degrees of hydrolysis can be utilized. Generally
the cold water soluble polyvinyl alcohol is at least about 70
percent hydrolyzed. Commercially available polyvinyl alcohols which
can be used in the scope of this embodiment include the material
sold by Du Pont under the trademark ELVANOL 50-42; and ELVANOL
52-22.
It is only necessary that the cold water soluble polymeric material
have a molecular weight sufficient to enable it to be molded by
suitable techniques such as extrusion, to form a thin plastic film
having a uniform thickness of between about 1 to about 3 mils. It
is preferred that the cold water soluble polymeric material have a
viscosity of at least about 25 centipoises, as measured in a 4
percent aqueous solution of the polymer at 20.degree.C by any
conventional method as hereinbefore described.
The preferred method of producing a sea disposable garbage
container of the subject invention includes initially forming a
blend of cold and hot water soluble polyvinyl alcohols and
thereafter forming a plastic sheet material which is then formed
into suitable garbage containers. Specifically, the polymer blend
can be produced by admixing from about 5 to about 65 parts by
weight of the cold water soluble polyvinyl alcohol with from about
95 to about 35 parts by weight of the hot water soluble polyvinyl
alcohol. More preferably, the blend is produced by admixing from
about 10 to about 50 parts by weight of the cold water soluble
polyvinyl alcohol with from about 90 to about 50 parts by weight of
the hot water soluble polyvinyl alcohol. The cold and hot water
polyvinyl alcohols can be admixed in powdered form and blended
thoroughly and thereafter melted and extruded in conventional
machinery.
The resulting container formed from the blend of cold and hot water
soluble polyvinyl alcohols possess sufficient structural integrity
and moisture-resistance to withstand normal household handling, and
handling during garbage pickup and delivery to a sea disposal
barge, for example. However, once the garbage container is
deposited in the ocean, water will readily dissolve the cold water
soluble polyvinyl alcohol, release the entrapped air from the bag
and thoroughly engulf the enclosed garbage to thereby allow natural
decomposition thereof. It is to be understood that any other
polymeric material which is compatible with the cold water soluble
polyvinyl alcohol can be used in place of the hot water soluble
polyvinyl alcohol in the scope of this embodiment, e.g.,
polyethylene oxide. However, because the hot water soluble
polyvinyl alcohol is biodegradable and has a low biochemical oxygen
demand, its use in this embodiment is highly preferred.
As an alternate to a container material which comprises a blend of
the cold water soluble polyvinyl alcohol and the hot water soluble
polyvinyl alcohol, suitable undersea degradable garbage bags can be
produced from laminated structures, such as illustrated in FIG. 3.
FIG. 3 is a partial sectional view of a sidewall of a suitable
laminated structure which can be utilized in accordance with this
invention. As shown, the sidewalls 30 of the container comprise a
layer 32 which is laminated by conventional techniques with layer
34. Layer 32 which serves as the substructure for sidewall 30 is
made of the aforementioned non-cold water soluble polymeric
material and preferably a hot water soluble polyvinyl alcohol.
Layer 34 comprises a cold water soluble polymeric material, e.g.,
the aforementioned cold water soluble polyvinyl alcohol material.
Furthermore, layer 32 carries a series of apertures 36
therethrough. The two films 32 and 34 can be produced by any
conventional film forming technique, and apertures 36 can be made
through film 34 either during the forming technique or afterwards
in a hole-punching operation. The number and size and configuration
of apertures 36 can be varied as desired. The two films are then
laminated together by suitable heat sealing techniques to yield a
composite laminate which generally comprises a double wall
thickness material except in areas of apertures 36. A container
made from the laminated material will maintain its structural
integrity during normal handling operations and in the presence of
minor amounts of moisture. However, when it is utilized in ocean or
fresh water disposal, film 34 will dissolve in the ocean water and
allow water to flow to the interior of the container via apertures
36. Thus, the container functions in the same manner as the
container made with the above-described blend of cold water soluble
polymer with a non-cold water soluble polymer.
Still a further embodiment of this invention is illustrated in FIG.
4. As shown, FIG. 4 is a partial sectional view of a portion of the
sidewall of a suitable container which can be used in the scope of
this invention, and is particularly useful for undersea disposal.
Sidewall 40 comprises a woven fiber innerlayer 42 which serves as a
substructure for sidewall 40 and is encapsulated by plastic layer
44. Layer 42 can comprise any knitted or woven reinforcing fibrous
material, but preferably a fibrous material which is made from the
aforementioned hot water soluble polyvinyl alcohol which is a
biodegradable material. Fiber layer 42 is encapsulated by layer 44
of the aforementioned cold water soluble polymeric material and
preferably polyvinyl alcohol. A garbage container made of this
material will function in undersea disposal in a similar manner as
a container made of the material illustrated in FIG. 3.
According to still another embodiment of this invention, either the
hot water soluble degradable garbage container of the invention
which is used in standard landfills or the underwater disposable
garbage container can carry suitable amounts of microencapsulated
liquid. For example, as shown in FIG. 5, microcapsules 50
containing liquid (microspheres) can be affixed to the surface of
container 10 by suitable techniques. One particularly suitable
technique for affixing the microencapsulated liquid to the surface
of container 10 involves the use of an annular nozzle or a ring of
nozzles positioned in alignment with an extruder die for a tube
such that the extruded tube passes therethrough. A gaseous stream
such as air or nitrogen carrying conventional microspheres
containing a suitable liquid is emitted from the nozzle means and
directed inwardly to impinge upon the extruded tube passing from
the extruder die. The impingement of the gaseous stream containing
the entrained microspheres upon the soft extruded tube implants the
microspheres in the soft sidewalls, and thereafter hardens the
sidewalls. The entire sidewall portion or preferably the lower or
middle sidewall portion of container 10 can be coated with
microencapsulated liquid such as water, for example. If desired,
only the upper sidewall portion for example, about the upper 10 to
30 percent of the container adjacent opening 11 can be treated with
suitable microspheres containing a microencapsulated liquid such as
a deodorant or disinfectant. When using a container made by this
process, the act of affixing tie wire 18 to the upper portion of
container 10 will burst the microspheres and release the liquid.
When container 10 carries microspheres containing water, heating or
special treating of the container during the garbage disposal will
burst the microspheres and moisten the polyvinyl alcohol to hasten
the degradation thereof. In addition, if desirable, minor amounts
of bacteria which will degrade the polymer film can be included
within the microencapsulated liquid. For example, conventional
bacteria normally found in a garbage disposal area can be used in
microspheres affixed to container 10 made of polyvinyl alcohol.
Alternately, if desired, the microencapsulated liquid can be molded
within the body of the film which forms container 10 by admixing
the microspheres with the polyvinyl alcohol before the film is
made. The microspheres containing liquid can be produced by any
conventional technique and can be made from any suitable
encapsulating material such as glass, epoxy resins, phenolic
resins, waxes, or polyvinyl alcohol. The conventionally produced
microspheres generally have diameters in the range of from about 5
to 5,000 microns and are preferably from about 20 to 150 microns in
diameter. These microspheres are conventionally utilized in the
manufacture of carbonless paper and sample paper containing various
microencapsulated odors. The microspheres can be ruptured by any
suitable method, depending upon the composition of the
encapsulating material. Suitable techniques include heat, pressure,
or techniques such as subjecting the container to high frequency
radio waves or ultraviolet or infrared radiation.
While this invention has been described in relation to its
preferred embodiments, it is to be understood that various
modifications thereof will now be apparent to one skilled in the
art upon reading this specification and it is intended to cover
such modifications which fall within the scope of the appended
claims.
* * * * *