U.S. patent application number 08/447063 was filed with the patent office on 2003-05-01 for laminated bags for containerization of toxic or hazardous materials.
Invention is credited to CHEN, CHI-YU R., EDWARDS, DAVID B., GOUGE, SAMUEL T., HODAKOWSKI, LEONARD E., MCCARTHY, WILLIAM J., WEBER, PAUL J..
Application Number | 20030080017 08/447063 |
Document ID | / |
Family ID | 27488728 |
Filed Date | 2003-05-01 |
United States Patent
Application |
20030080017 |
Kind Code |
A1 |
EDWARDS, DAVID B. ; et
al. |
May 1, 2003 |
LAMINATED BAGS FOR CONTAINERIZATION OF TOXIC OR HAZARDOUS
MATERIALS
Abstract
A package which comprises a hazardous chemical dissolved or
dispersed in a liquid or gel contained in a water soluble or water
dispersible laminated film. The laminated film construction
provides improved resistance to puncture or breakage thereby
providing an improved containerization system for toxic or
hazardous products.
Inventors: |
EDWARDS, DAVID B.; (ONGAR,
GB) ; MCCARTHY, WILLIAM J.; (ONGAR, GB) ;
HODAKOWSKI, LEONARD E.; (RALEIGH, NC) ; CHEN, CHI-YU
R.; (RALEIGH, NC) ; GOUGE, SAMUEL T.;
(RALEIGH, NC) ; WEBER, PAUL J.; (DURHAM,
NC) |
Correspondence
Address: |
EUGENE C. RZUCIDLO
MORGAN & FINNNEGAN,L.L.P.
345 PARK AVENUE, NEW YORK,
NEW YORK
NY
10154
|
Family ID: |
27488728 |
Appl. No.: |
08/447063 |
Filed: |
May 22, 1995 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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08447063 |
May 22, 1995 |
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08147602 |
Nov 4, 1993 |
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5429242 |
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08447063 |
May 22, 1995 |
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08041521 |
Mar 31, 1993 |
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5280835 |
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08447063 |
May 22, 1995 |
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07713681 |
Jun 11, 1991 |
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08447063 |
May 22, 1995 |
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07680321 |
Apr 4, 1991 |
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08447063 |
May 22, 1995 |
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07679290 |
Apr 2, 1991 |
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08447063 |
May 22, 1995 |
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07554615 |
Jul 18, 1990 |
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5080226 |
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Current U.S.
Class: |
206/484 ;
206/524.7 |
Current CPC
Class: |
B65B 29/10 20130101;
C05G 5/18 20200201; B65D 65/46 20130101; A01C 15/003 20130101; A01N
25/34 20130101; A01N 43/70 20130101; A01N 25/04 20130101; C05G 5/20
20200201; B65B 9/042 20130101; B65D 81/3272 20130101; A01N 39/04
20130101; A01N 37/40 20130101; C05G 5/40 20200201; A01N 53/00
20130101; C05G 5/45 20200201; A01N 37/40 20130101; A01N 2300/00
20130101; A01N 39/04 20130101; A01N 2300/00 20130101; A01N 43/70
20130101; A01N 2300/00 20130101; A01N 53/00 20130101; A01N 2300/00
20130101; C05G 5/45 20200201; C05G 5/20 20200201; C05G 5/18
20200201; C05G 5/45 20200201; C05G 5/20 20200201; C05G 5/45
20200201 |
Class at
Publication: |
206/484 ;
206/524.7 |
International
Class: |
B65D 073/00; B65D
085/84 |
Claims
What is claimed is:
1. A package which comprises a hazardous chemical dissolved or
dispersed in a liquid or gel contained in a water soluble or water
dispersible laminated film.
2. The package according to claim 1, wherein the chemical is an
agrochemical.
3. The package according to claim 1, wherein the hazardous chemical
is dissolved or dispersed in a liquid.
4. The package according to claim 1, wherein the hazardous chemical
is dissolved or dispersed in a gel.
5. The package according to claim 1, wherein the laminated film has
a thickness of from 10 to 250 microns.
6. The package according to claim 1, wherein the laminated film has
a thickness of from 15 to 80 microns.
7. The package according to claim 1, which has a content of
hazardous chemical of from 0.2 to 12 liters.
8. The package according to claim 1, which has a content of
hazardous chemcial of from 0.45 to 6 liters.
9. The package according to claim 1, wherein the water soluble or
water dispersible laminated film is insoluble in the liquid or gel
used to dissolve or disperse the hazardous chemical.
10. The package according claim 1, wherein at least one of the
layers of the film is selected from polyethylene oxide, methyl
cellulose or partially or fully alcoholysed or hydrolysed polyvinyl
acetate.
11. The package according to claim 10, wherein the said at least
one layer is 40-99% alcoholoysed or hydrolysed polyvinyl
acetate.
12. The package according to claim 10, wherein the said at least
one layer is 70-92% alcoholysed or hydrolysed polyvinyl
acetate.
13. The package according to claim 1, wherein at least two of the
layers of the laminated film are made of the same material.
14. The package according claim 1, wherein at least two of the
layers of the laminated film are made of a different material.
15. The package according claim 1, wherein the laminated film
consists essentially of two layers.
16. The package according to claim 15, wherein the ratio of the
thickness of the two layers is from 0.1 to 10.
17. The package according to claim 15, wherein the ratio of the
thickness of the two layers is from 0.5 to 2.
18. The package according to claim 4, wherein the gel has a
viscosity of 500 to 50,000 centipoise.
19. The package according to claim 4, wherein the gel has a
viscosity of 1000 to 12000 centipoise.
20. The package according claim 4, wherein the gel has a phase
difference phi between the controlled shear stress and the
resulting shear strain such that tg(phi) is less than or equal to
1.5.
21. The package according to claim 4, wherein the gel has a phase
difference phi between the controlled shear stress and the
resulting shear strain such that tg(phi) is less than or equal to
1.2.
22. The package according to claim 4, wherein the gel has a
spontaneity less than 75.
23. The package according to claim 4, wherein the gel has a
spontaneity less than 25.
24. The package according to claim 2 wherein the agrochemical is a
pesticide or a plant protection agent or a plant growth
regulator.
25. A process for the production of a package according to claim 1,
which comprises laminating two or more layers together by pressure,
heating, crosslinking, fusion or by means of water to obtain the
laminated film.
26. The package according to claim 1, wherein the package is filled
with the liquid or gel to at least 60% of capacity.
27. The package according to claim 1, wherein the package is filled
with the liquid or gel to at least 70% of capacity.
28. The package according to claim 1, wherein the package is filled
with the liquid or gel to at least 80 to 99% of capacity.
29. The package according to claim 1, wherein the package is filled
with the liquid or gel to at least 85 to 95% of capacity.
Description
[0001] This application is a continuation-in-part of a U.S. patent
application Ser. No. 07/680,321, filed Apr. 4, 1991, which is a
continuation-in-part of U.S. patent application Ser. No.
07/679,290, filed Apr. 2, 1991, and U.S. patent application Ser.
No. 07/554,615, filed Jul. 18, 1990, all of which are incorporated
herein by reference.
BACKGROUND OF THE INVENTION
[0002] I. Field of the Invention
[0003] This invention relates to a package comprising a liquid
chemical or chemical dissolved or dispersed in a liquid or gel
which is contained in an envelope of water soluble or water
dispersible material.
[0004] II. Discussion of the Prior Art
[0005] At present, most hazardous liquids are stored in metal drums
or, where smaller quantities are required, plastic containers.
[0006] Hazardous compounds, especially agrochemical compounds, are
formulated in a variety of ways. It is, however, especially
desirable for farmers to handle such compounds when they are in
liquid form. This facilitates the spreading of such compounds.
There are, however, difficulties and drawbacks in handling liquids.
The liquids can be spilled on the ground or may leak due to holes
in the containers. The containers may also rupture when subjected
to a physical shock.
[0007] It is thus difficult to devise a containerization system
that is suitable for farmers, safe for those handling the
containers and also safe for the environment.
[0008] It is known that agrochemicals may be contained in soluble
bags or sachets made from film. However, such films may crack and
break and thus cause spillage of the agrochemicals they contain. In
fact, a variety of defects may be present in films, which lead to
weaknesses of the film and consequently a potential source of
leakage. The presence of air bubbles, dust particles or other
foreign bodies, of gel particles or of thin points on or in the
film are all potential weak points. If a film with such a weak
point is subjected to a lot of handling or physical shock, the film
may fail at that point. This is especially a problem in the
agrochemical industry where containers may be subjected to rough or
unsafe handling by distributors or farmers.
[0009] The weaknesses of films mentioned above are present to a
greater or lesser extent in certain types of films, depending on
their method of manufacture. When films are made by casting, there
may be fewer pinholes, but there are more often tiny pieces of gel
inclusions. When films are made by extrusion, there are more
pinholes.
SUMMARY OF THE INVENTION
[0010] The present invention seeks to provide a new
containerization system for agrochemicals which is safe to
handle.
[0011] The invention further seeks to provide a new
containerization system for agrochemicals which is convenient for
endusers, e.g. farmers, to handle.
[0012] The invention further seeks to provide a new
containerization system for agrochemicals which reduces the risks
of pollution and environmental damage.
[0013] In one aspect, the invention seeks to avoid leakage of
liquid or dissolved chemicals through the pinholes of a film
containerization system. Although pinholes are generally rare, even
the presence of one pinhole in many thousands of containers is
enough to cause damage, since the liquid in the container passes
through the pinhole and contaminates the surrounding
environment.
[0014] Other objects and advantages of the invention will be
apparent from the description which follows.
DETAILED DESCRIPTION OF THE PRESENT INVENTION
[0015] The containerization system of the invention is
characterized in that a hazardous material in a liquid or gel form
is contained in a water soluble or water dispersible bag made of a
laminated film.
[0016] According to a preferred feature of the invention the
hazardous compounds are agrochemicals, e.g. pesticides or plant
protection agents or plant growth regulators.
[0017] The present invention accordingly provides a package which
comprises a hazardous chemical dissolved or dispersed in a liquid
or gel contained in a water soluble or water dispersible laminated
film.
[0018] In this specification the term laminated film means a film
which has been made from two or more originally separated layers
which are joined together. The two layers may be joined together in
the laminate by known methods. For example, the layers of the
laminate may be joined by pressure, heating, crosslinking, fusion,
adhesion or any combination thereof. Adhesion of the two layers may
be obtained through the use of a separate adhesive, or, when
appropriate, water.
[0019] When suitable water soluble or water dispersible layers are
used, a particularly convenient way to obtain a laminated film is
by adhesion of the separate layers, either using adhesive PVA
(generally of low molecular weight) and/or more simply by means of
water.
[0020] Because two or more layers are used to produce the laminated
film, the chance of pinholes occurring in the film is reduced to
almost nil. This is because it is unlikely that two pinholes in
separate layers will overlap. Furthermore, the tensile strength of
a multi (e.g. two) layer film is better than the tensile strength
of a similar film of the same thickness that is made of a single
layer.
[0021] The laminated films used in the invention generally have a
thickness of from 10 to 250 microns, preferably from 15 to 80
microns. The individual layers constituting the laminated films
which are used in the invention are generally each half of this
thickness. When two layers are used, the ratio of thickness of the
two layers is generally from 0.1 to 10, preferably from 0.5 to 2.
Bags or sachets made of laminated films according to the invention
generally have a content of from 0.2 to 12 liters, preferably from
0.45 to 6 liters.
[0022] The materials that may be used in the invention are water
soluble or water dispersible materials which are insoluble in
organic solvents used to dissolve or disperse the chemicals they
are used to contain. Suitable materials include polyethylene oxide
or methyl cellulose, but preferably the material comprises or is
derived from polyvinylalcohol, i.e. partially or fully alcoholysed
or hydrolysed, e.g., 40-99%, preferably 70-92% alcoholysed or
hydrolysed polyvinyl acetate films.
[0023] The layers of the laminated films of the invention may be
made of the same material or of different materials. Films made
from layers of different materials may have advantageous
properties. For example, an inner layer of a package may be made
more resistant to the agrochemical it contains. In addition, the
outer layer of the bag can be selected to have one or more of the
following properties:
[0024] i. to dissolve more quickly (compared to an inner layer or a
single layer package) in water,
[0025] ii. to have improved mechanical properties including
improved resistance to mechanical damage,
[0026] iii. to have improved machinability,
[0027] iv. to have less susceptibility to relative humidity,
[0028] v. to have resistance to freezing and/or high
temperatures.
[0029] One of more of the layers of the laminated film may contain
a plasticiser. A suitable plasticiser content in the inner layer
may improve the sealing properties of the film, and make the film
less likely to stretch. The film will thus be easier to process on
machinery and to seal around the hazardous liquid. A suitable
plasticiser content in the outside layer of the container makes the
outer surface more flexible and thus more resistant to physical
damage from low temperature or shock and movement.
[0030] The layers of the laminated film may be made using different
techniques, e.g., extrusion or casting. A laminate made from layers
produced by different methods may have advantageous properties
including greater flexibility, increased strength and increased
resistance to stretching. The increased strength and/or resistance
to stretching may be in one direction in the film. The laminated
films for use in the present invention are used to produce packages
which avoid the time-consuming and hazardous consequences of prior
art packages which leak in the filling process or during subsequent
handling due to film defects.
[0031] As already said, the bags (or containerization system) may
contain either liquids or gels. A preferred feature of the
invention is the bags or containerization system of the invention
containing a gel.
[0032] According to a particular feature of the invention, the gels
are chosen in such a way that one or more of the following features
are present:
[0033] the resulting gels form a continuous system and/or
[0034] the resulting gels have a viscosity of 500 to 50,000
centipoise, more preferably of 1000 to 12000 centipoise (these
viscosities are Brookfield viscosities measured with a viscosimeter
in form of a flat plate rotating at 20 round per minute)
[0035] the gel has a phase difference phi between the controlled
shear stress and the resulting shear strain such that tg(phi) is
less than or equal to 1.5, preferably less than or equal to 1.2.
Tg(phi) is the tangent of the angle phi (or phase difference). The
measurement of phi is made by means of a rheometer having a flat
fixed plate and a rotating cone above this plate such that the
angle between them is less than 10.degree., preferably less than
4.degree.. The cone is caused to rotate by means of a controlled
speed motor; the rotation is a sinusoidal one, i.e., the torque and
the angular displacement change as a sine function with time. This
angular displacement corresponds to the hereabove mentioned shear
strain; the torque of the controlled speed motor (which causes the
angular displacement) corresponds to the hereabove mentioned
controlled shear stress.
[0036] the gels preferably have a density greater than 1 gm/cc,
preferably greater than 1.1 gm/cc.
[0037] the gels have a spontaneity (as hereafter defined) less than
75, preferably less than 25.
[0038] The spontaneity is assessed according to the following
method: A mixture of 1 ml gel with 99 ml water are put into a 150
ml glass tube which is stoppered and inverted through 180.degree.
(upside down). The number of times required to completely disperse
the gel is called the spontaneity.
[0039] By the wording continuous system, it is meant a material
which is visually homogeneous, that is to say which has the visual
appearance of having only one physical phase; this does not exclude
the possibility of having small solid particles therein, provided
these particles are small enough not to constitute a visible
separate physical phase.
[0040] It is known that a gel is generally a colloid in which the
dispersed phase has combined with the continuous phase to produce a
viscous, jelly-like product; it is also a dispersed system
consisting typically of a high molecular weight compound or
aggregate of small particles in very close association with a
liquid.
[0041] In order to make a bag, the film needs to be shaped
(possibly partially sealed) and then filled with the gel. Generally
the gels are able to flow, even if it is a slow rate due to the
high viscosity. A container which is used to contain the gels
cannot be easily emptied due to this high gel viscosity (that is a
reason why the gels have not been used up to now in agriculture).
When filled, the bag must be finally sealed, generally heat sealed,
to be closed.
[0042] According to another feature, the bag of the invention is
filled to at least 60% of capacity with the agrochemical
composition-containing substance, more preferably at least 70% of
capacity, still more preferably 80 to 99% of capacity and most
preferably 85 to 95% of capacity. The bag is preferably not filled
to complete capacity because the unused capacity gives the bag
shock resistance, i.e., resistance to breakage when dropped,
transported or stored. This unused capacity may or may not contain
air or an inert gas. An absence of air or inert gas in the unused
capacity further improves shock resistance. However, in deciding
how much unused capacity, or absence of air or inert gas, to
provide, the advantages of shock resistance must be balanced
against the need, if any, for shock resistance and the cost of
providing shock resistance. For example, if the bag is stored
and/or transported in a shock absorbing container, then it may not
be as helpful to provide this unused capacity.
[0043] Also, the capacity to which the bag is filled, and whether
the unused capacity does or does not contain air or inert gas, is
affected by whether it is desired to have the bag sink or float.
Whether the bag sinks or floats will depend not only on the unused
capacity, but also on the density of the bag contents.
[0044] Further information may be found in the following copending
applications, the disclosures of which are incorporated herein by
reference: application of Leonard E. Hodakowski, Chi-Yu R. Chen,
Samuel T. Gouge and Paul J. Weber for "Gel Formulations for Use in
Toxic or Hazardous Product Containerization Systems" filed Jun. 11,
1991; application of Samuel T. Gouge, Leonard E. Hodakowski, Paul
J. Weber and Chi-Yu R. Chen for "Gel Formulations for Hazardous
Products" filed Jun. 11, 1991; application of Leonard E.
Hodakowski, Chi-Yu R. Chen, Samuel T. Gouge and Paul J. Weber for
"Water Dispersible Gel Formulations" filed Jun. 11, 1991;
application of Leonard E. Hodakowski, Ricky W. Couch, Samuel T.
Gouge and Robert C. Ligon for "Gel Formulations" filed Jun. 11,
1991; and application of Samuel T. Gouge and James E. Shue for "Bag
In A Bag For Containerization of Toxic or Hazardous Material" filed
Jun. 11, 1991.
[0045] The following Examples are given by way of illustration and
should not be understood to restrict the scope of the
invention.
EXAMPLE 1
[0046] A film in a roll form is constructed from two thinner films
by lamination: both films are made from a 88% hydrolysed polyvinyl
alcohol (cold water soluble), each 25 microns thick; one has a 17%
plasticiser content, the other has a 15% plasticiser content. The
two films are laminated together with heat (100.degree. C.) and
pressure to form one film of 50 microns thickness.
[0047] The film is then used to produce 1 liter sachets containing
a solvent based liquid herbicide (mixture of ioxynil and bromoxynil
esters) by using "form-and-fill" methods. The herbicide is a
solution in a C10 aromatic hydrocarbons mixture as solvent.
[0048] The film is placed on the machine so that the high
plasticiser layer is produced on the outside of the sachets. The
film is thus easy to process.
[0049] No leak is observed during the manufacture, handling, land
transporting of 500 sachets.
EXAMPLE 2
[0050] A gel is made by stirring at 50.degree. C. a mixture of:
[0051] Active ingredient: 2,4-D phenoxy benzoic acid isooctyl
ester): 64.8%
[0052] Solvent: aromatic solvent with flash point of 65.degree. C.:
24.2%
[0053] Surfactant: a mixture of
[0054] a non ionic/sulfonate blended emulsifier 4% and calcium
alkylbenzene sulfonate 1%
[0055] Gelling agent: mixture of dioctylsulfosuccinate salt and
sodium benzoate: 6%
[0056] The mixture is stirred and shaken until each component is
dissolved or dispersed.
[0057] During stirring, a dissolution appears, and thereafter a
gellation. Gellation is increased during the cooling at room
temperature (20.degree. C.).
[0058] The brookfield viscosity of the gel is 3000 centiposise.
[0059] The emulsion stability is good in the above described
test.
[0060] 1100 g of this gel are put in a 1 liter bag made of a film
of PVA similar to the film of example 1. The bag, which is almost
full (about 95% v/v), is heat sealed. The density both of the gel
and of the bag containing the gel is 1.1.
[0061] The bag is then dropped 10 times from 1.2 m onto the ground.
No breaking or leakage is observed.
[0062] Another bag made in the same way as the previous one is
tested for pinhole protection. A needle (diameter: 0.6 mm) is
passed through the bag. It is observed that a small droplet forms
at the locus where the needle passed, but this droplet was small
enough not to drop from the bag and not to flow along the bag.
* * * * *