U.S. patent application number 10/977150 was filed with the patent office on 2005-05-05 for water dispersible products.
This patent application is currently assigned to HOLLINGSWORTH & VOSE COMPANY. Invention is credited to Choi, Wai Ming, Yu, Howard.
Application Number | 20050092451 10/977150 |
Document ID | / |
Family ID | 34549418 |
Filed Date | 2005-05-05 |
United States Patent
Application |
20050092451 |
Kind Code |
A1 |
Choi, Wai Ming ; et
al. |
May 5, 2005 |
Water dispersible products
Abstract
Water dispersible fiber products are provided. In one
embodiment, a water dispersible fiber sheet is provided and it is
preferably formed from regenerated cellulose fibers, a second fiber
that is adapted to provide strength to the water dispersible fiber
sheet, and a water soluble binder. In use, the fiber sheet can be
formed into a variety of products including, for example, for
labels, packaging, medical and health care products. The fiber
sheet is particularly advantageous in that it is readily
dispersible upon contact with water, yet it will retain its
strength when used with other fluids, such as alcohol and oils. The
biodegradability of the fiber sheet will also allow the fibers to
be consumed naturally by environmental bacteria, thus eliminating
the need for special disposal procedures. In another embodiment,
the water dispersible fiber sheet can be incorporated into a filter
media.
Inventors: |
Choi, Wai Ming; (West
Newton, MA) ; Yu, Howard; (Northborough, MA) |
Correspondence
Address: |
NUTTER MCCLENNEN & FISH LLP
WORLD TRADE CENTER WEST
155 SEAPORT BOULEVARD
BOSTON
MA
02210-2604
US
|
Assignee: |
HOLLINGSWORTH & VOSE
COMPANY
|
Family ID: |
34549418 |
Appl. No.: |
10/977150 |
Filed: |
October 29, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60515480 |
Oct 29, 2003 |
|
|
|
Current U.S.
Class: |
162/146 ;
162/141; 162/158; 162/175; 162/178 |
Current CPC
Class: |
B01D 39/18 20130101;
B01D 2239/064 20130101; C08L 2205/16 20130101; B01D 2239/0266
20130101; B01D 39/1615 20130101; B01D 39/163 20130101; D21H 11/12
20130101 |
Class at
Publication: |
162/146 ;
162/141; 162/158; 162/175; 162/178 |
International
Class: |
D21H 013/00; D21H
017/00 |
Claims
What is claimed is:
1. A water dispersible fiber sheet, comprising: a first fiber
comprising regenerated cellulose; a second fiber adapted to provide
strength to the water dispersible fiber sheet; and a water soluble
binder.
2. The water dispersible fiber sheet of claim 1, wherein the water
dispersible fiber sheet includes about 20% to 90% of the first
fiber, about 10% to 80% of the second fiber, and less than about
10% of the water soluble binder.
3. The water dispersible fiber sheet of claim 1, wherein the second
fiber includes about 10% to 80% of a natural fiber and about 0% to
50% of a synthetic fiber.
4. The water dispersible fiber sheet of claim 1, wherein the water
soluble binder is added to the water dispersible fiber sheet by
applying the water soluble binder to the first and second fibers
after the first and second fibers are formed into a fiber
sheet.
5. The water dispersible fiber sheet of claim 1, wherein the water
soluble binder is added to the water dispersible fiber sheet by
mixing the water soluble binder with the first and second fibers
before the mixture is formed into a water dispersible fiber
sheet.
6. The water dispersible fiber sheet of claim 1, wherein the second
fiber is selected from the group consisting of natural fibers,
synthetic fibers, and combinations thereof.
7. The water dispersible fiber sheet of claim 6, wherein the
natural fibers are selected from the group consisting of softwood
fibers, hardwood fibers, vegetation fibers, and combinations
thereof.
8. The water dispersible fiber sheet of claim 6, wherein the
synthetic fibers are selected from the group consisting of
polyethylene terephthalate fibers, nylon fibers, polyolefin fibers,
synthetic wood pulp fibers, polyvinyl alcohol fibers, acrylic
fibers, modacrylic fibers, vinyl chloride fibers, vinylidene
chloride fibers, acetate fibers, regenerated protein fibers,
polylactide fibers, poly(lactide-co-glycolide- ) fibers, glass
fibers, ceramic fibers, metal fibers, mineral fibers, and
combinations thereof.
9. The water dispersible fiber sheet of claim 1, wherein the water
soluble binder is selected from the group consisting of water
soluble carboxymethyl cellulose, polyethylene oxide, polyvinyl
alcohol, protein, polyacrylic acid, starches, gums, and
combinations thereof.
10. The water dispersible fiber sheet of claim 1, wherein the fiber
sheet will disperse in less than about 20 seconds when agitated in
water.
11. The water dispersible fiber sheet of claim 1, wherein the fiber
sheet will disperse in less than about 10 seconds.
12. The water dispersible fiber sheet of claim 1, wherein the fiber
sheet will disperse in less than about 5 seconds.
13. The water dispersible fiber sheet of claim 1, wherein the fiber
sheet has an MD tensile strength that is at least about 2
lb/inch.
14. The water dispersible fiber sheet of claim 1, wherein the first
fiber has a length in the range of about 1 mm to 10 mm.
15. The water dispersible fiber sheet of claim 1, wherein the
second fiber has a length in the range of about 0.1 mm to 6 mm.
16. The water dispersible fiber sheet of claim 1, wherein the
second fiber has a size that is in the range of about 0.1.mu. to
100.mu..
17. The water dispersible fiber sheet of claim 1, wherein the
second fiber has a length to diameter ratio that is less than about
1000.
18. The water dispersible fiber sheet of claim 1, wherein the
second fiber has a length to diameter ratio that is less than about
500.
19. The water dispersible fiber sheet of claim 1, wherein the
second fiber has a length to diameter ratio that is less than about
200.
20. The water dispersible fiber sheet of claim 1, wherein the fiber
sheet is not soluble in organic liquids.
21. The water dispersible fiber sheet of claim 1, wherein the fiber
sheet is not soluble in alcohol.
22. The water dispersible fiber sheet of claim 1, wherein the water
dispersible fiber sheet forms a first layer of a filter media, the
filter media further comprising a second layer formed from a water
soluble non-woven polymer fiber web.
23. The water dispersible fiber sheet of claim 22, wherein the
water soluble non-woven polymer fiber web is formed from a water
soluble polyether amide.
24. The water dispersible fiber sheet of claim 22, wherein the
second layer is meltblown onto the first layer.
25. The water dispersible fiber sheet of claim 22, wherein the
first and second layers are adhered to one another with a water
soluble polymer.
26. A water dispersible filter media, comprising: a first layer
formed from regenerated cellulose fibers, a second fiber adapted to
provide strength to the water dispersible fiber sheet, and a water
soluble binder; and a second layer formed from a water soluble
non-woven polymer fiber web.
27. The water dispersible filter media of claim 26, wherein the
water soluble binder in the first layer is selected from the group
consisting of water soluble carboxymethyl cellulose, polyethylene
oxide, polyvinyl alcohol, protein, polyacrylic acid, starches,
gums, and combinations thereof.
28. The water dispersible filter media of claim 26, wherein the
water soluble non-woven polymer fiber web is formed by extrusion of
a water soluble polymer.
29. The water dispersible filter media of claim 26, wherein the
water soluble non-woven polymer fiber web is formed from a water
soluble polyether amide.
30. The water dispersible filter media of claim 26, wherein the
second layer is meltblown onto the first layer.
31. The water dispersible filter media of claim 26, wherein the
first and second layers are adhered to one another with a water
soluble polymer.
32. The water dispersible filter media of claim 26, where in the
first and second layer are heat sealed to form a bag.
33. A method for making a water dispersible product, comprising:
forming a first fiber sheet layer from regenerated cellulose
fibers, a second fiber adapted to provide strength to the water
dispersible fiber sheet, and a water soluble binder.
34. The method of claim 33, wherein the step of forming a first
fiber sheet layer comprises: forming a fiber mixture containing the
regenerated cellulose fibers, the second fiber, and water; passing
the mixture through a paper machine to form a fiber sheet; and
applying a water soluble binder to the sheet.
35. The method of claim 33, wherein the step of forming a first
fiber sheet layer comprises forming a fiber mixture containing the
regenerated cellulose fibers, the second fiber, the water soluble
binder, and water, and passing the mixture through a paper machine
to form a fiber sheet.
36. The method of claim 33, further comprising the step of melt
blowing a water soluble non-woven polymer fiber onto the first
layer to form a second fiber sheet layer.
37. The method of claim 36, wherein the water soluble non-woven
polymer fiber is formed from a water soluble polyether amide.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority from U.S. Provisional
Patent Application Ser. No. 60/515,480, filed on Oct. 29, 2003,
entitled "Water Dispersible Products," which is hereby expressly
incorporated by reference in its entirety.
FIELD OF THE INVENTION
[0002] The present invention relates to water dispersible
products.
BACKGROUND OF THE INVENTION
[0003] With the increasing concern for the environment, it is
desirable to provide products that can be easily disposed of and/or
recycled. The products should have sufficient strength while they
are dry, and they should be capable of dissolving upon contact with
water. While some water dispersible products are available, they
are limited to certain uses and/or they require expensive and
time-consuming manufacturing techniques. Accordingly, there remains
a need for a water dispersible product that can be used for a
variety of purposes, that readily dissolves upon contact with
water, and that is efficient to produce.
SUMMARY OF THE INVENTION
[0004] The present invention provides water dispersible products
for use in a variety of applications. In one embodiment, a water
dispersible fiber sheet is provided and it is formed from at least
two types of fibers: regenerated cellulose fibers, and a second
fiber that is adapted to provide strength to the water dispersible
fiber sheet. The water dispersible fiber sheet also preferably
includes a water soluble binder, i.e., a binder that is adapted to
lose strength upon coming into contact with water. An exemplary
water soluble binder is carboxymethyl cellulose (CMC). In use, the
fiber sheet is adapted to disperse upon contact with water. In an
exemplary embodiment, the fiber sheet is used for labels,
packaging, medical and health care products, such as wipes and
identification markers, or for industrial and personal use. In
another embodiment, the water dispersible fiber sheet forms part of
a filter media. In an exemplary embodiment, the filter media
includes a first layer formed from a water dispersible fiber sheet,
and a second layer formed from a water soluble meltblown non-woven
fiber web. The water soluble meltblown non-woven fiber web can be
formed from, for example, a polymer containing a polyether amide.
The filter media can be used in a variety of air filtration
applications, such as vacuum filters, filter bags, face masks,
organic liquid filters, and ASHRAE filtration applications. When
the filter media is disposed of, it is adapted to disperse upon
contact with water.
[0005] The present invention also provides a method for preparing a
water dispersible fiber sheet by combining regenerated cellulose
fibers, a second fiber adapted to provide strength to the water
dispersible fiber sheet, and a water soluble binder. The sheet is
then formed from the fibers and the binder, preferably using
standard paper-making techniques, and the sheet is adapted to
disperse upon contact with water. The sheet can also be combined
with one or more layers of a meltblown fiber web to form a filter
media.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] The invention will be more fully understood from the
following detailed description taken in conjunction with the
accompanying drawing, in which:
[0007] FIG. 1 is a photograph of one embodiment of a water
dispersible fiber sheet in the dry form according to the present
invention;
[0008] FIG. 2 is a photograph of the water dispersible fiber sheet
shown in FIG. 1 after being sprayed with water for about three (3)
seconds;
[0009] FIG. 3 is a photograph of the water dispersible fiber sheet
shown in FIG. 1 after being sprayed with water for about five (5)
seconds;
[0010] FIG. 4 is a photograph of a pleated filter media; and
[0011] FIG. 5 is a photograph of a heat sealed filter bag.
DETAILED DESCRIPTION OF THE INVENTION
[0012] The present invention generally provides a water dispersible
fiber sheet that, in an exemplary embodiment, is formed from
regenerated cellulose fibers, a second fiber that is adapted to
provide strength to the water dispersible fiber sheet, and a water
soluble binder. In use, the fiber sheet can be formed into a
variety of products including, for example, medical and health
products such as packaging and labels. In another embodiment, the
fiber sheet can be incorporated into a filter media. The fiber
sheet is particularly advantageous in that it is readily
dispersible upon contact with water, yet it will retain its
strength when used with non-aqueous fluids, such as alcohol, oils,
and organic solvents. The biodegradability of the fiber sheet will
also allow the fibers to be consumed naturally by environmental
bacteria, thus eliminating the need for special disposal
procedures. In the case of a dispersible sheet which does not need
to be biodegradable, synthetic fiber can be used in place of the
regenerated cellulose.
[0013] A variety of different types of regenerated cellulose fibers
can be used to form the fiber sheet of the present invention.
Suitable types of regenerated cellulose fibers include, for
example, viscose rayon, cuprammonium rayon, high wet modulus rayon,
polynosic rayon, saponified acetate, and cellulose triacetate. In
one embodiment, the regenerated cellulose fibers can be present in
the fiber sheet in the range of about 20% to 90% by weight. In an
exemplary embodiment, however, the regenerated cellulose fibers are
present in the fiber sheet in the range of about 30% to 70% by
weight. The fibers are preferably relatively short, and in
particular they preferably have a length in the range of about 1 mm
to 10 mm. This allows the fibers to disperse more readily when
placed into contact with water.
[0014] The second fiber used to form the fiber sheet can also be
present in a variety of forms. In an exemplary embodiment, however,
the second fiber is a natural fiber that is biodegradable. The
second fiber can, however, also include synthetic fibers. Natural
fibers such as softwood fibers and hardwood fibers are preferred,
but other suitable fibers include, for example, synthetic fibers
such as polyethylene terephthalate fibers, nylon fibers, polyolefin
fibers, synthetic wood pulp fibers, polyvinyl alcohol fibers,
acrylic fibers, modacrylic fibers, vinyl chloride fibers,
vinylidene chloride fibers, acetate fibers, regenerated protein
fibers, polylactide fibers, poly(lactide-co-glycolide) fibers,
glass fibers, ceramic fibers, metal fibers, mineral fibers, and
combinations thereof. Other suitable fibers include non-wood
vegetation fibers such as cotton, seed flax, hemp, abaca,
eucalyptus, sisal, bamboo, kenaf, jute, esparto, papyrus, sugar
cane base, corn straw, wheat straw, rice straw, ramie, and
combinations thereof.
[0015] When used to form a fiber sheet, the second fiber is
effective to provide tensile strength and/or to control the density
of the sheet. In one embodiment, the second fiber can be present in
the fiber sheet in the range of about 10% to 75% by weight, and
more preferably the second fiber includes natural fibers that are
present within the sheet in the range of about 10% to 80% by
weight, and synthetic fibers that are present within the sheet in
the range of about 0% to 50% by weight. In an exemplary embodiment,
however, the second fiber is present in the fiber sheet in the
range of about 30 to 60% by weight. The size of the second fiber
can also vary, especially for the natural fibers. In an exemplary
embodiment, the second fiber has a diameter that is in the range of
0.1.mu. to 100.mu., and more preferably that is in the range of
about 0.3.mu. to 70.mu., and most preferably that is in the range
of about 0.3.mu. to 40.mu., and they have a length that is in the
range of about 0.1 mm to 6 mm. The second fiber can also have a
length to diameter ratio that is less than about 1000, and more
preferably that is less than about 500, and most preferably that is
less than about 200. The short length of the fibers is particularly
advantageous in that it allows the fibers to more readily disperse
when placed into contact with water.
[0016] As previously stated, the fiber sheet also includes a binder
that is effective to bind the regenerated cellulose fibers and the
second fiber to one another. A variety of binders can be used, but
the binder should be water soluble to allow the fiber sheet to
readily disperse upon coming into contact with water. Suitable
binders include, for example, carboxylmethyl cellulose (CMC),
polyvinyl alcohol, protein, polyethylene oxide, polyacrylic acid,
starches, gums and combinations thereof. The binder should be
present within the fiber sheet in the range of about 0.05% to 10%
by weight. In an exemplary embodiment, the binder is water soluble
sodium CMC, which has ideal adsorption, adhesion, water binding,
film forming, viscosifying, and dispersing properties. An exemplary
water soluble CMC binder is manufactured by Hercules Incorporated,
in Wilmington, Del., and it is sold under the name Aqualon.RTM.
CMC, which is an anionic water soluble polymer.
[0017] A person skilled in the art will appreciate that the water
dispersible fiber sheet can include a variety of other components,
in addition to the regenerated cellulose fibers, the second fiber,
and the binder. By way of non-limiting example, the fiber sheet can
include wetting agents, additives, mineral fillers such as titanium
oxide, calcium carbonate, silica and silicates. While the amount of
wetting agent present in the composition will vary depending on the
type of wetting agent and the composition of the fiber sheet, in an
exemplary embodiment the wetting agent is present in the range of
about 0.01% to 1.0% by weight. One example of a suitable wetting
agent is sulfonated oil.
[0018] A variety of techniques can be used to form a water
dispersible fiber sheet in accordance with the present invention,
but preferably the regenerated cellulose fibers, the second fiber,
e.g., hardwood and/or softwood fibers, and the binder are all
combined and formed into a fiber sheet using standard paper-making
techniques. The binder can be added to the fiber sheet using a
beater-addition process, or it can be coated, sprayed, saturated or
foamed saturated onto the fiber sheet during formation of the
sheet. An exemplary method for making a fiber sheet in accordance
with the present invention will be discussed in more detail
below.
[0019] In use, the fiber sheet can be formed into a variety of
products including, for example, labels, packaging, components for
medical, personal and industrial use, embroidery backing, paper
bags, printing and/or writing paper, decorative paper, pouches,
alcohol wipes, polishing wipes, industrial wipes, automotive and
aerospace wipes, filters, fragrance sheets for bathing, publication
inserts, seeding beds, cotton swabs, test paper, backing paper,
toiletries, paper core, paper box, wipes, applicators and strips
for health care, cosmetic and personal care, home care wipes,
packaging for baby, adult diapers and feminine hygiene, etc.
[0020] In an exemplary embodiment of the present invention, the
water dispersible fiber sheet has a breaking strength when dry of
about 8 lb/in, but the sheet is adapted to disperse upon coming
into contact with water such that it has no breaking strength when
wet. This is illustrated in FIGS. 1-3. FIG. 1 shows a dry fiber
sheet, FIG. 2 shows the sheet after being spraying with water for
less than 3 seconds, and FIG. 3 shows the sheet after being spray
with water for about 5 seconds. As shown, the fibers in the sheet
begin to disperse after 3 seconds, and the sheet falls apart after
5 seconds. This is particularly advantageous in that it allows the
user to simply place the sheet into contact with water.
[0021] In another embodiment of the present invention, the water
dispersible fiber sheet can be incorporated into a filter media to
form a water dispersible filter media. While the filter media can
have a variety of configurations, and it can be formed using any
number of layers of fiber webs formed from various polymeric
materials, in one exemplary embodiment the filter media includes a
first layer formed from a water dispersible fiber sheet as
previously described, and a second layer formed a water soluble
non-woven meltblown polymer fiber web. The first and second layers
can be mated to one another using a variety of techniques known in
the art, but in an exemplary embodiment the layers are adhered
together using a water soluble adhesive, such as a water soluble
polymer.
[0022] The non-woven meltblown polymer fiber web can be formed from
virtually any water soluble polymeric material. In an exemplary
embodiment, the non-woven polymer fiber web is formed from a water
soluble polyether amide. One method for producing the polyether
amide is by reacting at least one polyalkylene glycol diamine with
at least one dicarboxylic acid or ester. The polyalkylene glycol
diamine preferably has the formula
NH2--(CH2)x--(OCH2--CH2)y--O--(CH2)Ox--NH2, where x ranges from 2
to 3 and y ranges from 1 to 2. An exemplary water soluble polyether
amide resin for use with various embodiments of the present
invention is Hydromelt.TM., available from H.B. Fuller, Inc.
[0023] The resin can be formed into a non-woven meltblown polymer
fiber web by extruding the resin into fibers. An exemplary process
for forming a meltblown polymer fiber web is described in more
detail in U.S. Pat. No. 6,780,226, which is incorporated herein by
reference in its entirety. In an exemplary embodiment, the fibers
are meltblown onto the first layer, i.e., the water dispersible
fiber sheet, which functions as a support layer for the meltblown
fibers. The resulting fiber web can be comprised of fibers having a
relatively broad distribution of fiber diameters, and the fiber
diameter can be adjusted during the extrusion process to form a
filter media having a desired filtration efficiency as needed based
on the intended use. In one exemplary embodiment, the average fiber
diameter can be in the range of about 5.mu. to 20.mu., and more
preferably about 1.mu. to 15.mu.. The basis weight of the meltblown
polymer fiber web can also vary, especially considering the
intended application. In general, higher web basis weights yield
better filtration, but there exists a higher resistance, or
pressure drop, across the filter barrier when the filter media has
a higher basis weight. For most applications, the basis weight can
be in the range of about 10 g/m.sup.2 to 520 g/m.sup.2, and more
preferably from about 30 g/m.sup.2 to 200 g/m.sup.2. One of
ordinary skill in the art can readily determine the optimal web
basis weight, considering such factors as the desired filter
efficiency and permissible levels of resistance. Furthermore, the
number of plies of the polymer fiber web used in any given filter
application can also vary. Each ply of the polymer fibrous web can
be of a different fiber diameter. One of ordinary skill in the art
can readily determine the optimal number of plies to be used.
[0024] The following non-limiting examples serve to further
illustrate the present invention.
EXAMPLE 1
[0025] A cellulose binder spray was made with 1889 g of Hercules
Aqualon.RTM. CMC in 50 gallons of water. The solution was mixed
until the CMC was completely dissolved. Trax H-10 wetting agent,
produced by Nippon Yushi, was then added to the solution, which was
set aside. 8 lbs. of Prince George bleached softwood pulp and 300
gallons of water were combined in a hydropulper and agitated until
the pulp was dispersed. 32 lbs. of Minifiber Rayon 0.8
denier.times.2 mm was then added to the hydropulper and agitated
until the fibers were dispersed. The fiber mixture was then
transferred to a tank with a total of 1200 gallons of water and
stock. A fiber sheet was then formed on a fourdrinier paper
machine, and the sheet was sprayed with the CMC solution, and dried
to form a water dispersible fiber sheet.
[0026] The resulting fiber sheet had a basis weight of about 32
lb/3000 ft.sup.2, a thickness of about 0.012 in., a tensile
strength of about 8 lb/in, and a peak elongation of about 1.6%.
EXAMPLE 2
[0027] A first layer was formed by combining 30 lbs. of Primacell
eucalyptus pulp, 6 lbs. of Prince George bleached softwood pulp, 12
lbs. of Minifiber Rayon 0.8 denier.times.2 mm, 18 lbs. of Diawabo
Rayon 0.6 denier.times.3 mm, and 50 lbs. of Hercules Aqualon.RTM.
CMC in 1500 gallons of water. The fiber mixture was then passed
through a fourdrinier paper machine and dried to form a water
dispersible fiber sheet having a basis weight of 60 g/m.sup.2.
[0028] A second layer of a water soluble non-woven meltblown
polymer fiber web was then formed by meltblowing H.B. Fuller
Hydromelt NP2116 onto the first layer. The basis weight of the
second layer was 40 g/m.sup.2. The resulting filter media is
referred to below as Sample 1.
[0029] The above process was repeated to form a second filter
media, referred to below as Sample 2, having a first layer with a
basis weight of 60 g/m.sup.2 and a second layer with a basis weight
of 80 g/m.sup.2.
[0030] Table 1 illustrates the resulting properties of the first
layer, Sample 1, and Sample 2.
1TABLE 1 Basis MD MD 0.3.mu. DOP Air weight Tensile elongation
efficiency Resistance SAMPLE (g/m.sup.2) (lbs/in) (%) (%) (mm
H.sub.2O) First Layer 60 4.16 1.17 98.1 0.8 Sample 1 100 5.31 1.65
92.7 1.1 Sample 2 140 4.64 1.74 84.6 1.5
[0031] The filter media can optionally be formed into a pleated
filter, as shown in FIG. 4, or it can be formed into a filter bag
by heat seat, as shown in FIG. 5.
EXAMPLE 3
[0032] A water dispersible paper was formed by combining 30 lbs. of
Primacell eucalyptus pulp, 6 lbs. of Prince George bleached
softwood pulp, 12 lbs. of Minifiber Rayon 0.8 denier.times.2 mm, 18
lbs. of Diawabo Rayon 0.6 denier.times.3 mm, and 50 lbs. of
Hercules Aqualon.RTM. CMC in 1200 gallons of water. The fiber
mixture was then passed through a fourdrinier paper machine and
dried to form a water dispersible fiber sheet having a basis weight
of 60 g/m.sup.2.
[0033] The resulting sheet has a tensile in excess of 4 lbs./in and
it can be easily processed using a paper converting process, such
as printing, die cutting, sheeting, etc. The resulting sheet can be
easily dispersed in water within 20 seconds.
EXAMPLE 4
[0034] A water dispersible paper was formed by combining 30 lbs. of
Primacell eucalyptus pulp, 6 lbs. of Prince George bleached
softwood pulp, 12 lbs. of Minifiber Rayon 0.8 denier.times.2 mm, 18
lbs. of Diawabo Rayon 0.6 denier.times.3 mm, and 50 lbs. of
Hercules Aqualon.RTM. CMC in 1200 gallons of water. The fiber
mixture was then passed through a fourdrinier paper machine and
dried to form a water dispersible fiber sheet having a basis weight
of 60 g/m.sup.2. The paper was sprayed with an Eastman AQ
copolyester having an intrinsic viscosity of about 0.2. The AQ
copolyesters are soluble in water, but they are not soluble in
saline or body fluids. The resulting paper can be used for hospital
wipes, after which they can be placed in water and eventually
dissolved for disposal.
EXAMPLE 5
[0035] A water dispersible paper was formed by combining 30 lbs. of
Primacell eucalyptus pulp, 6 lbs. of Prince George bleached
softwood pulp, 12 lbs. of Minifiber Rayon 0.8 denier.times.2 mm, 18
lbs. of Diawabo Rayon 0.6 denier.times.3 mm, and 50 lbs. of
Hercules Aqualon.RTM. CMC in 1200 gallons of water. The fiber
mixture was then passed through a fourdrinier paper machine and
dried to form a water dispersible fiber sheet having a basis weight
of 60 g/m.sup.2. The fiber sheet is then laminated to another layer
of paper using an adhesive, such as Hydromelt NP2116. The adhesive
can be coated onto the paper at a weight ranging from 0.1 g/m.sup.2
to 20 g/m.sup.2. The resulting paper can be formed into a disposal
bag, such as a shopping bag, leaf bag, or commercial bags for
powder, pellets, flakes and granular materials such as sugar,
chemicals, resin, etc. After use, the bag can be disposed of in the
environment where exposure to rain and moisture will dissolve the
bag. The bag can also easily be recycled into a usable fiber in the
paper making process.
EXAMPLE 6
[0036] Several samples of water dispersible papers were formed from
2.41 grams of Primacell eucalyptus pulp, 0.48 grams of Prince
George bleached softwood pulp, 2.41 grams of Minifiber Rayon 0.8
denier.times.2 mm in 1000 ml of water, along with various amounts
of Hercules Aualon.RTM. CMC. The CMC of different degrees of
substitution and molecular weight, and levels was either added to
the mixture, passed through a handsheet mold, and dried to form a
water dispersible fiber sheet, or it was sprayed onto the sheet
after the sheet was formed and dried to form a water dispersible
fiber sheet. The samples were vacuumed and dried on photodryers,
and the resulting samples were tested for tensile strength using a
tensile machine which showed results of about 1.5 to 3 lb./in. The
basis weight was 35 lb./3000ft.sup.2. The dispersing time was
measured by the time it takes for a 2 inch strip to tear apart from
being sprayed by a spray bottle three inches away. The results are
listed below in Table 2.
2 TABLE 2 Dispersing Furnish Spray Basis weight time Runs 7MT 7MT_1
7H 9H (lb/3000 ft.sup.2) Tensile (lb/in) (sec) 1 0.000% 0.000%
0.000% 0.000% 32 1.42 4 2 0.010% 0.050% 0.000% 0.000% 34 2.07 5 3
0.020% 0.000% 0.000% 0.000% 34 1.43 6 4 0.010% 0.000% 0.000% 0.000%
35 1.46 6 5 0.020% 0.050% 0.000% 0.000% 34 2.37 7 6 0.000% 0.100%
0.000% 0.000% 36 2.32 4 7 0.000% 0.050% 0.000% 0.000% 36 2.07 5 8
0.010% 0.100% 0.000% 0.000% 35 2.98 11 9 0.020% 0.100% 0.000%
0.000% 35 2.81 5 10 0.010% 0.000% 0.050% 0.000% 35 2.37 8 11 0.020%
0.000% 0.050% 0.000% 34 2.15 9 12 0.000% 0.000% 0.100% 0.000% 35
2.73 11 13 0.000% 0.000% 0.050% 0.000% 34 1.89 8 14 0.010% 0.000%
0.100% 0.000% 36 2.79 11 15 0.020% 0.000% 0.100% 0.000% 34 2.72 14
16 0.010% 0.000% 0.000% 0.050% 35 1.95 9 17 0.020% 0.000% 0.000%
0.050% 34 1.96 14 18 0.000% 0.000% 0.000% 0.100% 35 2.81 14 19
0.000% 0.000% 0.000% 0.050% 34 1.87 6 20 0.010% 0.000% 0.000%
0.100% 34 2.99 22 21 0.020% 0.000% 0.000% 0.100% 34 2.86 14
EXAMPLE 7
[0037] A water dispersible paper was formed by combining 40%
eucalyptus pulp, 10% softwood pulp, 50% of Minifiber Rayon 0.8
denier.times.2 mm and passing the mixture through a fourdrinier
paper machine. The resulting sheet was saturated with CMC with a
basis weight of 35 lb./3000 ft.sup.2. The original caliper or
thickness of the sheet was 0.0083 inches, and with calendaring a
caliper of 0.0021 inches could be achieved. Table 3 shows the
calendaring conditions and the resulting caliper. The caliper
reduction can be as high as 5 to 1.
3 TABLE 3 Top Load Cell Bottom Load Cell Thickness Interval psi psi
inches B NA NA 0.0083 8 2,500 NA 0.0052 7 3,000 NA 0.0051 6 3,000
56,000 0.0031 5 3,000 68,000 0.0024 4 3,000 80,000 0.0031 3 3,000
100,000 0.0023 2 3,000 150,000 0.0036 1 3,000 200,000 0.0021
EXAMPLE 8
[0038] A water dispersible paper was formed by combining 47.5%
eucalyptus pulp, 5% softwood pulp, 47.5% of Minifiber Rayon 0.8
denier.times.2 mm. The composition was saturated with CMC with a
basis weight of 35 lb./3000ft.sup.2, and then passed through a
handsheet mold. Table 4 shows that with an increasing level of
CMC-7MT added to the composition before it is formed into a sheet
and/or sprayed onto the resulting sheet after it is formed, the
tensile strength increases but the dispersion time remains less
than 6 seconds.
4 TABLE 4 7MT 7MT Tensile Disperse time Mold Spray (lb/in) (sec)
0.02% 0.50% 6.3 5 0.00% 0.50% 5.8 4 0.02% 0.25% 3.9 5 0.00% 0.25%
2.9 5 0.01% 0.25% 2.9 6 0.01% 0.50% 4.8 4
EXAMPLE 9
[0039] A water dispersible paper was formed by various combinations
of eucalyptus pulp, softwood pulp and rayon fibers of different
deniers for the base composition. The pulp can also be refined to a
lower Canadian Standard Freeness (CSF) such as the Prince George
pulp at 600 CSF. The composition was passed through a handsheet
mold. A 1.5% CMC solution was made up with various CMC, such as
Aqualon.RTM. CMC-7MT, Noviant Finnfix.RTM. 30G, 300 and 700. The
compositions was saturated with CMC to a basis weight of 38
lb./3000 ft.sup.2.
[0040] Table 5 shows the type and level of both pulp and CMC
solution. The samples were tested using Dispersion Time Test A,
which is the time it takes for the sample to fall apart while hand
spraying a strip of about 1".times.2" sample with cold water from
about 3 inches away, and using Dispersion Time Test B, which is the
time it takes for a 1".times.1" sample to fall apart in 300 ml of
water using a VWR Dynadual.RTM. 942009 magnetic stir plate and a
magnetic stir rod at a stir setting of 5.
5TABLE 5 1.5% CMC Minifiber Diawabo Prince George (g) Crestbrook
(g) Primacell (g) Suzano (g) Dip Rayon (g) Rayon (g) A 0.00 1.27
0.00 1.76 30G 1.47 2.41 B 0.00 1.27 0.00 1.76 300 1.47 2.41 C 0.00
1.27 0.00 1.76 700 1.47 2.41 D 0.00 1.27 0.00 1.76 7MT 1.47 2.41 E
0.294 or 15 ml 0.00 2.65 0.00 7MT 1.47 2.41 (600CSF) F 0.294 or 15
ml 0.00 2.65 0.00 300 1.47 2.41 (600CSF) G 1.18 0.00 1.76 0.00 300
1.47 2.41 Dispersion Dispersion Thickness Basis weight Tensile
Elongation Time Test Time Test B Air Perm (inches) (#/ream) (lb/in)
(%) A (sec) (sec) (cfm) A 0.0106 38 16.5 2.3 2 4 56.7 B 0.0095 39
18.3 3.4 3 6 44.9 C 0.0087 39 24.1 4.0 2 7 43.6 D 0.0089 38 18.4
4.4 3 5 49.7 E 0.0084 37 25.3 4.0 2 6 32.7 F 0.0099 42 20.5 3.8 2 4
61.6 G 0.0097 38 18.1 4.3 2 5 63.6
[0041] One skilled in the art will appreciate further features and
advantages of the invention based on the above-described
embodiments. Accordingly, the invention is not to be limited by
what has been particularly shown and described, except as indicated
by the appended claims. All publications and references cited
herein are expressly incorporated herein by reference in their
entirety.
* * * * *