U.S. patent application number 13/011977 was filed with the patent office on 2011-05-19 for hydrophilic polypropylene fibers having antimicrobial activity.
This patent application is currently assigned to 3M Innovative Properties Company. Invention is credited to Jeffrey F. Andrews, Wayne K. Dunshee, Thomas P. Klun, Debra M. Neu, Kevin R. Schaffer, Matthew T. Scholz.
Application Number | 20110117176 13/011977 |
Document ID | / |
Family ID | 27384701 |
Filed Date | 2011-05-19 |
United States Patent
Application |
20110117176 |
Kind Code |
A1 |
Klun; Thomas P. ; et
al. |
May 19, 2011 |
HYDROPHILIC POLYPROPYLENE FIBERS HAVING ANTIMICROBIAL ACTIVITY
Abstract
Polypropylene fibers and devices that include a fatty acid
monoglyceride added to the polypropylene as a melt additive are
described. A hydrophilic enhancer material can be advantageously
added to the polypropylene as a melt additive to enhance the
hydrophilicity of the fibers and devices. An antimicrobial enhancer
material can be added to the fibers to enhance the antimicrobial
activity.
Inventors: |
Klun; Thomas P.; (Lakeland,
MN) ; Dunshee; Wayne K.; (Maplewood, MN) ;
Schaffer; Kevin R.; (Woodbury, MN) ; Andrews; Jeffrey
F.; (Stillwater, MN) ; Neu; Debra M.; (River
Falls, MN) ; Scholz; Matthew T.; (Woodbury,
MN) |
Assignee: |
3M Innovative Properties
Company
|
Family ID: |
27384701 |
Appl. No.: |
13/011977 |
Filed: |
January 24, 2011 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
10885150 |
Jul 6, 2004 |
7879746 |
|
|
13011977 |
|
|
|
|
09572811 |
May 17, 2000 |
6762339 |
|
|
10885150 |
|
|
|
|
60135381 |
May 21, 1999 |
|
|
|
60153626 |
Sep 13, 1999 |
|
|
|
Current U.S.
Class: |
424/443 ;
264/211; 424/400; 428/220; 442/301; 442/304; 442/414; 502/402;
514/557; 604/372 |
Current CPC
Class: |
A61F 2013/8414 20130101;
D06M 13/207 20130101; Y10T 442/3976 20150401; Y10T 442/2525
20150401; B32B 2535/00 20130101; D01F 6/06 20130101; A61L 2300/21
20130101; B32B 27/02 20130101; A61L 15/24 20130101; B32B 2262/0253
20130101; B32B 2307/7265 20130101; Y10T 442/696 20150401; D01F
1/103 20130101; B32B 2305/08 20130101; B32B 2555/02 20130101; B32B
5/02 20130101; A61F 13/531 20130101; D01F 6/46 20130101; A61L 15/24
20130101; B32B 2307/724 20130101; B32B 2307/728 20130101; D06M
16/00 20130101; D01F 11/06 20130101; D01F 1/10 20130101; A61F
13/8405 20130101; B32B 2307/7145 20130101; A61L 2300/404 20130101;
A61L 15/20 20130101; Y10T 442/40 20150401; D06M 13/184 20130101;
B32B 2323/00 20130101; C08L 23/12 20130101; A61L 15/46
20130101 |
Class at
Publication: |
424/443 ;
502/402; 424/400; 514/557; 442/414; 442/301; 442/304; 428/220;
604/372; 264/211 |
International
Class: |
A01N 25/10 20060101
A01N025/10; B01J 20/26 20060101 B01J020/26; A01N 37/36 20060101
A01N037/36; A01P 1/00 20060101 A01P001/00; D04H 1/00 20060101
D04H001/00; D03D 15/00 20060101 D03D015/00; D04H 1/56 20060101
D04H001/56; B32B 27/02 20060101 B32B027/02; B32B 27/18 20060101
B32B027/18; A61L 15/22 20060101 A61L015/22; D01F 1/10 20060101
D01F001/10 |
Claims
1. An absorbent device comprising: an absorbent layer comprising
hydrophilic polypropylene fibers having incorporated therein a
C.sub.8 to C.sub.16 fatty acid monoglyceride and a hydrophilic
enhancer material.
2. The absorbent device of claim 1 wherein the monoglyceride is
selected from the group consisting of glycerol monocaprylate,
glycerol monocaprate, and glycerol monolaurate.
3. The absorbent device of claim 1 wherein the hydrophilic enhancer
material is incorporated prior to fiber formation in an amount from
about 2 to about 25 weight percent.
4. The absorbent device of claim 1 wherein the hydrophilic enhancer
material is selected from the group consisting of polybutylene,
polybutylene copolymers ethylene/octene copolymers, and atactic
polypropylene.
5. The absorbent device of claim 1 wherein the hydrophilic enhancer
material is selected from the group consisting of sorbitan
monolaurate and sorbitan monopalmitate.
6. The absorbent device of claim 1 wherein the hydrophilic enhancer
material is a mixture of a polybutylene and a sorbitan
monolaurate.
7. The absorbent device of claim 1 wherein the monoglyceride is a
C.sub.8 to C.sub.12 fatty acid monoglyceride.
8. The absorbent device of claim 1 wherein the surface of the
fibers is treated with an effective amount of an antimicrobial
enhancer material such that the fiber is antimicrobial to
Gram-negative bacteria.
9. The absorbent device of claim 8 wherein the antimicrobial
enhancer material is selected from the group consisting of organic
acids and chelating agents.
10. The absorbent device of claim 1, wherein the absorbent layer
absorbs greater than 900% as measured by the Percent Water
Absorbency Test.
11. The absorbent device of claim 1, further comprising an
absorbent additive.
12. The absorbent device of claim 1, wherein the absorbent additive
is selected from the group consisting of wood pulp, cellulose,
cotton, rayon, recycled cellulose, shredded cellulose sponge, and
mixtures thereof.
13. The absorbent device of claim 1, wherein the thickness of the
absorbent layer is from about 0.5 to about 10 mm.
14. An absorbent device comprising: an absorbent layer comprising
hydrophilic polypropylene fibers having incorporated therein an
effective amount of a C.sub.12 fatty acid monoglyceride such that
the fiber is hydrophilic, and an effective amount of an
antimicrobial enhancer material, wherein the fiber is antimicrobial
to Gram-positive bacteria and to Gram-negative bacteria.
15. The absorbent device of claim 14 wherein the polypropylene
fibers additionally have incorporated therein a hydrophilic
enhancer material.
16. The absorbent device of claim 15 wherein the hydrophilic
enhancer material is a selected from the group consisting of
polybutylene, polybutylene copolymers ethylene/octene copolymers,
and atactic polypropylene.
17. The absorbent device of claim 14 wherein the monoglyceride is a
C.sub.8 to C.sub.12 fatty acid monoglyceride.
18. The absorbent device of claim 14 wherein the antimicrobial
enhancer material is selected from the group consisting of organic
acids and chelating agents.
19. The absorbent device of claim 14, wherein the absorbent layer
absorbs greater than 900% as measured by the Percent Water
Absorbency Test.
20. The absorbent device of claim 14, further comprising an
absorbent additive.
21. The absorbent device of claim 20, wherein the absorbent
additive is selected from the group consisting of wood pulp,
cellulose, cotton, rayon, recycled cellulose, shredded cellulose
sponge, and mixtures thereof.
22. The absorbent device of claim 14, wherein the thickness of the
absorbent layer is from about 0.5 to about 10 mm.
23. An absorbent device comprising: (a) an absorbent layer
comprising (i) hydrophilic polypropylene fibers having incorporated
therein an effective amount of a glycerol monolaurate, and the
surface of the fiber is covered by a dry coating containing an
effective amount of lactic acid, wherein the fiber is antimicrobial
to Gram-positive bacteria and to Gram-negative bacteria, and (ii)
an absorbent additive; (b) a liquid-impermeable and moisture
vapor-permeable backing sheet adhered to an outer surface of the
absorbent layer.
24. The absorbent device of claim 23 further comprising a
hydrophilic enhancer material incorporated into the fibers, the
hydrophilic enhancer material being selected from the group
consisting of a polybutylene, a polybutylene copolymer, a sorbitan
monolaurate, a sorbitan monopalmitate, and mixtures thereof.
25. The absorbent device of claim 23, wherein the absorbent
additive is selected from the group consisting of wood pulp,
cellulose, cotton, rayon, recycled cellulose, shredded cellulose
sponge, and mixtures thereof.
26. A fibrous nonwoven, woven or knit web or batt, the web or batt
comprising hydrophilic polypropylene fibers having incorporated
therein a C.sub.8 to C.sub.16 fatty acid monoglyceride and a
hydrophilic enhancer material.
27. The web or batt of claim 26 wherein the monoglyceride is
selected from the group consisting of glycerol monocaprylate,
glycerol monocaprate, and glycerol monolaurate.
28. The web or batt of claim 26 wherein the hydrophilic enhancer
material is incorporated prior to fiber formation in an amount from
about 2 to about 25 weight percent.
29. The web or batt of claim 26 wherein the hydrophilic enhancer
material is selected from the group consisting of polybutylene,
polybutylene copolymers ethylene/octene copolymers, and atactic
polypropylene.
30. The web or batt of claim 26 wherein the surface of the fibers
is treated with an effective amount of an antimicrobial enhancer
material such that the fiber is antimicrobial to Gram-negative
bacteria.
31. A fibrous nonwoven, woven or knit web or batt, the web or batt
comprising hydrophilic polypropylene fibers having incorporated
therein an effective amount of a C.sub.12 fatty acid monoglyceride
such that the fiber is hydrophilic, and an effective amount of an
antimicrobial enhancer material, wherein the fiber is antimicrobial
to Gram-positive bacteria and to Gram-negative bacteria.
32. The web or batt of claim 31 wherein the polypropylene fibers
additionally have incorporated therein a hydrophilic enhancer
material.
33. The web or batt of claim 32 wherein the hydrophilic enhancer
material is a selected from the group consisting of polybutylene,
polybutylene copolymers ethylene/octene copolymers, and atactic
polypropylene.
34. A method of preparing hydrophilic fibers comprising: (a)
preparing a hot melt mixture comprising melted polypropylene and
sufficient amounts of (i) at least one C.sub.8 to C.sub.16 fatty
acid monoglyceride and (ii) a hydrophilic enhancer material that
are effective to impart hydrophilicity to the fibers; and (b)
extruding the mixture into fibers.
35. The method of claim 34 wherein the hydrophilic enhancer
material is selected from the group consisting of a polybutylene, a
polybutylene copolymer, a sorbitan monolaurate, and mixtures
thereof.
36. The method of claim 34 wherein the monoglyceride is a glycerol
monolaurate.
37. A method of preparing fibers that are both hydrophilic and
antimicrobial to Gram-positive and Gram-negative bacteria,
comprising: (a) preparing a hot melt mixture comprising melted
polypropylene and an amount of at least one C.sub.8 to C.sub.12
fatty acid monoglyceride that is effective to impart both
hydrophilicity and antimicrobial activity to Gram-positive bacteria
to the surface of the fiber; (b) extruding the mixture into fibers;
(c) contacting the fibers with a liquid composition comprising at
least one antimicrobial enhancer material, thereby cooling and at
least partially solidifying the fibers to yield an essentially dry
coating of the antimicrobial enhancer material on the surface of
the fibers that is of sufficient concentration and uniformity such
that the fiber surface is antimicrobial to Gram-negative
bacteria.
38. The method of claim 37 further comprising incorporating an
effective amount of a hydrophilic enhancer material in the
polypropylene to enhance the hydrophilicity of the fibers.
39. The method of claim 38 wherein the hydrophilic enhancer
material is selected from the group consisting of a polybutylene, a
polybutylene copolymer, a sorbitan monolaurate, a sorbitan
monopalmitate, and mixtures thereof.
40. The method of claim 37 wherein the monoglyceride is a glycerol
monolaurate.
41. The method of claim 38 wherein the hydrophilic enhancer
material is a sorbitan monolaurate and the antimicrobial enhancer
material is an organic acid or a chelating agent.
42. The method of claim 37 wherein the antimicrobial enhancer
material is a lactic acid.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a division of U.S. patent application
Ser. No. 10/885,150, filed Jul. 6, 2004, now U.S. Pat. No.
7,879,746, issuing on Feb. 1, 2011, which is a division of U.S.
patent application Ser. No. 09/572,811, filed May 17, 2000, now
U.S. Pat. No. 6,762,339, issuing on Jul. 13, 2004 which claims the
benefit of U.S. Provisional Application No. 60/135,381, filed May
21, 1999, and U.S. Provisional Application No. 60/153,626, filed
Sep. 13, 1999, the disclosures of which are hereby fully
incorporated by reference herein.
FIELD OF THE INVENTION
[0002] In one aspect, this invention relates to hydrophilic
polypropylene fibers which preferably have antimicrobial activity.
In another aspect it relates to a multilayer absorbent device
suitable as, e.g., a wound dressing, a medical drape, and the
like.
SUMMARY OF THE INVENTION
[0003] Briefly, in one aspect, the invention provides a
polypropylene fiber having incorporated therein a C.sub.8 to
C.sub.16 fatty acid monoglyceride or a mixture of glycerides
containing at least 80 percent by weight of one or more C.sub.8 to
C.sub.16 fatty monoglycerides, and a hydrophilic enhancer material.
The invention includes fibrous nonwoven, woven and knit webs and
batts made from such fibers.
[0004] In another aspect, the invention provides a hydrophilic
polypropylene fiber comprising: (a) polypropylene; (b) an effective
amount of at least one C.sub.8 to C.sub.12 fatty acid monoglyceride
added to the polypropylene as a melt additive to impart both
hydrophilicity and antimicrobial activity to Gram-positive bacteria
to the surface of the fiber; and (c) an effective amount of an
antimicrobial enhancer material such that the surface of the fiber
is antimicrobial to Gram-negative bacteria such as Klebsiella
pneumoniae. Preferred antimicrobial enhancer materials include
organic acids and chelating agents, most preferably lactic
acid.
[0005] In another aspect, the invention provides an absorbent
device comprising: (a) an absorbent layer having upper and lower
opposed, major surfaces and comprising fibers that are hydrophilic
and, preferably, antimicrobial to Gram-positive bacteria; and (b) a
liquid-impermeable and moisture vapor permeable backing sheet
adhered to the upper surface of the absorbent layer. The fibers
comprise polypropylene and an effective amount of at least one
C.sub.8 to C.sub.16 fatty acid monoglyceride added to the
polypropylene as a melt additive to render the surface of the
fibers hydrophilic and, preferably, antimicrobial. In one preferred
embodiment of this invention, the surface of the hydrophilic fibers
are treated with an effective amount of an antimicrobial enhancer
material, such as lactic acid, such that the surface of the fibers
in the absorbent layer are antimicrobial to Gram-negative
bacteria.
[0006] In one embodiment of the absorbent device, the absorbent
layer and backing sheet are substantially coextensive. When the
absorbent device is used as a wound dressing, it can be positioned
over the wound with the absorbent layer positioned adjacent to the
wound. The device is then adhered to the skin around the wound, for
example, by tape. In another embodiment of the absorbent device,
the absorbent layer and the backing sheet are not substantially
coextensive and the backing sheet extends beyond at least a portion
of the outer perimeter of the absorbent layer to form an extended
portion with an upper and lower surface. The lower surface of the
extended portion is adjacent to the absorbent layer and at least a
portion of the lower surface carries an adhesive layer which can be
used to adhere the absorbent device to the skin around the wound.
Optionally, this embodiment can further comprise a release liner
that is substantially coextensive with the backing sheet and
adhered to the backing sheet by the adhesive layer. The release
liner would be removed from the absorbent device prior to
application to a wound.
[0007] A preferred embodiment of the absorbent device further
comprises a liquid-permeable sheet that is substantially
coextensive with, and adhered to, the lower surface of the
absorbent layer. The liquid permeable sheet permits passage of
liquid, e.g., exudate, from the wound into the absorbent layer, and
preferably prevents adherence of the absorbent layer to the wound.
Optionally, the liquid permeable sheet can be hydrophilic or
antimicrobial, or both.
[0008] The invention also provides useful devices made from such
fibers, such as fabrics, webs, batts, and single and multi-layer
nonwoven constructions, which are employed in the manufacture of
wound dressings, medical drapes, surgical gowns, surgical masks,
disposable diapers, filter media, face masks, orthopedic cast
padding/stockinettes, respirators, food packaging, dental floss,
industrial wipes, textiles, and battery separators. In particular,
the absorbent device of the present invention can advantageously be
used as a wound dressing because it can (i) absorb a substantial
quantity of wound exudate when the dressing is worn for an extended
period of time or when the wound produces a large quantity of
exudate, and (ii) retard growth of bacteria in the absorbent layer,
and, in some cases, in the wound. A further advantage of the
absorbent device is that the antimicrobial activity of the device
reduces the sterilization load associated with the wound dressing
when the device is sterilized prior to packaging such as, for
example, by exposure to ethylene oxide.
[0009] The invention further provides a method of preparing fibers
that are both hydrophilic and, preferably, antimicrobial to
Gram-positive and Gram-negative bacteria, the method comprising the
steps of (i) preparing a hot melt mixture comprising melted
polypropylene and an amount of at least one C.sub.8 to C.sub.16
fatty acid monoglyceride that is effective to impart both
hydrophilicity and, preferably, antimicrobial activity to
Gram-positive bacteria to the surface of the fiber; and (ii)
shaping the mixture into the desired shape, for example forming the
fibers by extrusion through a die. When it is desired that the
fibers also be antimicrobial to Gram-negative bacteria, the method
further comprises the step of contacting the shaped mixture with a
liquid composition comprising at least one antimicrobial enhancer
material, thereby cooling and at least partially solidifying the
shaped mixture and, when present, evaporating sufficient solvent or
carrier liquid from the liquid composition to yield an essentially
dry coating of the antimicrobial enhancer material on the surface
of the shaped mixture that is of sufficient concentration and
uniformity such that the extruded surface is antimicrobial to
Gram-negative bacteria. When both hydrophilicity and antimicrobial
activity are desired, preferably the monoglyceride is a C.sub.8 -
C.sub.12 fatty acid monoglyceride, such as, for example, glycerol
monolaurate. Some embodiments of the aforementioned fibers further
incorporate an effective amount of a hydrophilic enhancer material
added to the polypropylene as a melt additive to enhance the
hydrophilicity of the fibers.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] For a better understanding of the invention, reference may
be made to the following description of exemplary embodiments taken
in conjunction with the accompanying drawings, in which:
[0011] FIG. 1 is a schematic cross-sectional view of an absorbent
device according to the invention.
[0012] FIG. 2 is a schematic cross-sectional view of another
absorbent device according to the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0013] As used herein, "hydrophilic", "hydrophilicity" or similar
terminology is used to describe substrates (e.g., fibers, woven or
nonwoven fabrics, webs, knits or fiber batts etc.) that can be wet
by water, by aqueous solutions of acids and bases (e.g., aqueous
potassium hydroxide) and by polar liquids (e.g. sulfuric acid and
ethylene glycol).
[0014] As used herein, "antimicrobial" or "antimicrobial activity"
means that a material has sufficient antimicrobial activity as
measured by American Association of Textile and Color Chemists
(AATCC) Test Method 100-1993 (AATCC Technical Manual, 1997, pp. 143
to 144), to reduce an initial bacterial load by at least 90% over a
24-hour exposure period at 23-24.degree. C.
[0015] The terms "fiber" and "fibrous" as used herein refer to
particulate matter, generally comprising thermoplastic resin,
wherein the length to diameter ratio of the particulate matter is
greater than or equal to about 10. Fiber diameters may range from
about 0.5 micron up to at least 1,000 microns and each fiber may
have a variety of cross-sectional geometries, may be solid or
hollow, and may be colored by, e.g., incorporating dye or pigment
into the polymer melt prior to extrusion.
[0016] The term "nonwoven web" or "nonwoven fabric" means a web or
fabric having a structure of individual fibers which are interlaid,
but not in a regular manner, such as knitting and weaving. Nonwoven
fabrics or webs have been formed from many processes such as, for
example, melt blowing processes, spunbonding processes, and bonded
carded web processes.
[0017] The term "spunbonded fibers" refers to small diameter fibers
which are formed or "spun" by extruding molten thermoplastic
material in the form of filaments from a plurality of fine, usually
circular, capillaries of a spinneret, and then rapidly reducing the
diameter of the extruded filaments, for example, by the methods
described in U.S. Pat. No. 4,340,563 (Appel et al.) and U.S. Pat.
No. 3,692,618 (Dorschner et al.). The "spun" fabric is then passed
between the rolls of a heated calender to bond the fibers together.
Various patterns can be imparted to the fabric by the calender
rolls, but the principle purpose of bonding is to increase the
integrity of the fabric. The bond area in thermal bonding is
usually about 15%, but may vary widely depending on the desired web
properties. Bonding may also be accomplished by needling,
hydroentanglement, or other methods known in the art.
[0018] The term "melt blown fibers" refers to fibers which are
typically formed by extruding the molten thermoplastic material
through a plurality of fine, usually circular, die capillaries as
molten threads or filaments into a high velocity, usually heated
gas (e.g., air) stream which attenuates the filaments of molten
thermoplastic material to reduce their diameter. Thereafter, the
melt-blown fibers are carried by the high velocity gas stream and
are deposited on a collecting surface to form a web of randomly
disbursed melt-blown fibers. Any of the nonwoven webs may be made
from a single type of fiber or two or more fibers which differ in
composition and/or thickness. Alternatively, sheath-core fibers can
be extruded containing different polymer compositions in each
layer, or containing the same polymer composition in each layer but
employing the more hydrophilicity-imparting component in the outer
sheath layer.
[0019] The polymers useful in preparation of the hydrophilic fibers
of the present invention are polypropylenes, including isotactic
polypropylene, syndiotactic polypropylene, and mixtures of
isotactic, atactic and/or syndiotactic polypropylene.
[0020] The monoglycerides useful in the invention are derived from
glycerol and medium to long chain length (i.e., C.sub.8 to
C.sub.16) fatty acids such as caprylic, capric, and lauric acids.
Most preferably, the monoglycerides are derived from C.sub.10 to
C.sub.12 fatty acids and are food grade and Generally Regarded as
Safe ("GRAS") materials. Examples of preferred monoglycerides
include glycerol monolaurate, glycerol monocaprate, and glycerol
monocaprylate. Because the monoglycerides useful in the invention
are typically available in the form of mixtures of unreacted
glycerol, monoglycerides, diglycerides and triglycerides, it is
preferred to use mixtures that contain a high concentration (e.g.,
greater than about 80%, preferably greater than about 85 wt. %,
more preferably greater than about 90 wt. %, and most preferably
greater than about 92 wt. %) of the monoglyceride. A convenient way
to determine whether one of the aforementioned mixtures, or even a
particular monoglyceride, will work in the invention is to
calculate the hydrophilic-lipophilic balance ("HLB value") for the
mixture. Typically, the HLB value of one of the aforementioned
mixtures decreases with increasing fatty acid chain lengths, and
also decreases as the diglyceride and triglyceride content in the
mixture increases. Useful materials (including pure monoglycerides)
typically have HLB values of about 4.5 to about 9, more preferably
from about 5.3 to about 8.5. Examples of particularly useful
commercially available materials include those available from
Med-Chem Laboratories, East Lansing, Mich., under the tradename
LAURICIDIN.TM., Riken Vitamin Ltd., Tokyo, Japan under the
tradename POEM.TM., and Henkel Corp. of Germany under the tradename
"MONOMULS.TM. 90 L-12".
[0021] Generally, it is difficult to impart hydrophilicity to
polypropylene fibers using surfactants. Conventional surfactants
typically must be added to polypropylene at higher concentrations
than are used in polyethylene, and it is difficult to find
effective surfactants that can be used in polypropylene at low
concentrations. The impact of the use of high concentrations of
conventional surfactants is increased cost, in some instances
impairment of the physical properties of the extruded fiber, or
impairment of processability of the extrudable polyolefin mixture
(e.g., screw slippage, see T. Klun, et al., "Hydrophilic Melt
Additives, Synergistic Fluorochemical/Hydrocarbon Surfactant
Mixtures," Proceedings of INDA-TEC '97, Cambridge, Mass., Sep.
8-10, 1997). It is quite surprising that the monoglycerides used in
this invention can impart good hydrophilicity to polypropylene at
concentrations of only about 3 weight percent or less, when
typically at least about 5 weight percent of other hydrocarbon
surfactants is required to impart acceptable hydrophilicity to
polypropylene.
[0022] The fibers of this invention can be made by blending or
otherwise uniformly mixing at least one C.sub.8 to C.sub.16 fatty
acid monoglyceride and the solid polypropylene, for example, by
intimately mixing the monoglyceride with pelletized or powdered
polymer, and melt extruding the mixture into a fibrous web using
any of the commonly known processes for producing nonwoven webs,
such as by using the spunbonding techniques or melt-blowing
techniques, or combinations of the two, described above. The
monoglyceride can be mixed per se with the polypropylene, or it can
be mixed with the polymer in the form of a "masterbatch"
(concentrate) of the monoglyceride in the polymer. Masterbatches
can typically contain from about 10% to as much as about 25% by
weight of the monoglyceride. Also, an organic solution of the
monoglyceride can be mixed with the powdered or pelletized polymer,
the mixture dried to remove solvent, then melted and extruded into
the desired shape. Alternatively, the neat form of monoglyceride
can be injected into a molten polymer stream to form a blend just
prior to extrusion into the desired shape. After extrusion, an
annealing step may be carried out to enhance hydrophilicity.
Preferably, the article is annealed at a temperature and for a time
sufficient to increase the amount of monoglyceride at the surface
of the article. Effective time and temperature will bear an inverse
relationship to one another and a wide variety of conditions will
be suitable. Using polypropylene, for example, the annealing
process can be conducted below the melt temperature at about
60.degree. to about 80.degree. C. for a period of about 30 seconds
to about 5 minutes or more. In some cases, the presence of moisture
during annealing can improve the effectiveness of the
monoglyceride. The annealing of a fibrous web can be carried out,
for example, in combination with other processing steps for the web
(e.g., during the warm cycle of an ethylene oxide sterilization
cycle). Hydrophilicity may also be enhanced by contacting the
shaped article with heated surfaces, such as hot rolls at about
60.degree. C. to 100.degree. C. for about 10-60 seconds.
[0023] Melt-blown hydrophilic fibers useful in the present
invention can be prepared as described in U.S. Pat. No. 3,849,241
(Butin et al.) and U.S. Pat. No. 5,064,578 (Insley et al.), or from
microfiber webs containing particulate matter such as those
disclosed, for example, in U.S. Pat. No. 3,971,373 (Braun), U.S.
Pat. No. 4,100,324 (Anderson), and U.S. Pat. No. 4,429,001 (Kolpin
et al.). Multilayer constructions of nonwoven fabrics enjoy wide
industrial and commercial utility and include such uses as fabrics
for medical gowns and drapes. The nature of the constituent layers
of such multilayer constructions can be varied according to the
desired end use characteristics, and can comprise two or more
layers of melt-blown and spun-bond webs in many useful
combinations, such as those described in U.S. Pat. No. 5,145,727
(Potts et al.) and U.S. Pat. No. 5,149,576 (Potts et al.). In
particular, a process similar to that described in Wente, Superfine
Thermoplastic Fibers, 48 INDUS. ENG'G CHEM. 1342(1956), or in Wente
et al., MANUFACTURE OF SUPERFINE ORGANIC FIBERS, (Naval Research
Laboratories Report No. 4364, 1954), can be used for the
preparation of the nonwoven webs of this invention. However,
because of the potential for thermal instability of the glycerol
monoesters employed in the invention as melt additives, it is
preferable to incorporate the monoester into the polymer melt just
before or just after the die, such as is generally described in
U.S. Pat. No. 4,933,229 (Insley et al.) and U.S. Pat. No. 5,064,578
(Insley et al.).
[0024] Preferred hydrophilic enhancer materials include
polybutylene, polybutylene copolymers, ethylene/octene copolymers,
atactic polypropylene, and certain sorbitan monoesters.
Polybutylene and its copolymers, such as, for example, polybutylene
0200, polybutylene 0400, polybutylene 0800, polybutylene DP 8310,
and polybutylene DP 8340 (all available from Shell Chemical Co.),
ethylene/octene copolymers, such as, for example, ENGAGE.TM. 8401
and 8402 (available from DuPont Dow Elastomer), ethylene/butylene
and butylene/ethylene copolymers, for example, EXACT.TM. 4023
(available from Exxon) and MONTELL.TM. dp-8340 (AVAILABLE FROM
Montell), and atactic poly(alpha)olefins, such as APAO-2180-E8
atactic polypropylene, a high molecular weight homopolymer of
polypropylene, available from Rexene Co., may be incorporated as an
additional polymer melt additive to enhance the hydrophilic
properties of the extrudate. Effective concentrations of the
polybutylene homopolymer and copolymers, determined by measuring
the amount incorporated as a melt additive prior to fiber
formation, range from about 2 to about 25% by weight, and
preferably from about 5% to about 15% by weight. The enhancement
effect is seen at polybutylene levels up to about 25% by weight,
and at monoglyceride concentrations as low as 1.0% by weight, based
on the weight of the composition prior to fiber formation.
[0025] C.sub.8 to C.sub.16, preferably C.sub.12 to C.sub.16
sorbitan monoesters such as SPAN.TM. 20 (sorbitan monolaurate) or
SPAN.TM. 40 (sorbitan monopalmitate) for example EXACT.TM. 4023
(available from Exxon) and MONTELL.TM. DP-8340 (available from
Montell), in combination with the monoglyceride, with or without
polybutylene, can further enhance the hydrophilic properties of the
extrudate. These monoesters both enhance the hydrophilicity of the
web and allow the web to maintain its hydrophilicity after aging at
ambient conditions. When these hydrophilic enhancer materials are
used, they may replace from about 10% to about 50% of the
monoglyceride, preferably from about 30% to about 50%.
[0026] In addition to the hydrophilic fibers of the present
invention, the nonwoven webs or fabrics and fiber batts can further
include commonly used hydrophilic fillers such as, for example,
wood pulp, cellulose, cotton, rayon, recycled cellulose, and
shredded cellulose sponge, as well as adhesive binders and
antistats.
[0027] Any of a wide variety of constructions, especially
multilayer constructions such as spunbond/melt-blown/spunbond
("SMS") constructions, may be made from the above-described fibers
and fabrics, and such constructions will find utility in
applications requiring hydrophilicity. Such constructions include
aqueous media absorbent devices such as diapers, feminine care
products, and adult incontinence products, which utilize the fiber
and fabrics as at least a portion of their fluid-absorbing "core"
element. "Absorbent device" as used herein refers to a consumer
product that is capable of absorbing significant quantities of
water and other aqueous fluids (i.e., liquids) such as body fluids.
Examples of aqueous media absorbent devices include wound
dressings, disposable diapers, sanitary napkins, tampons,
incontinence pads, disposable training pants, paper towels,
geofabrics, facial tissues, medical drapes and masks, medical
gowns, and the like. The fabrics of the present invention are
particularly suitable for use in devices like sanitary napkins,
diapers, and incontinence pads.
[0028] Aqueous media absorbent devices frequently will comprise a
substantially aqueous media impervious and moisture vapor-permeable
backing sheet, an aqueous media permeable top sheet, and an aqueous
media absorbent core comprising at least one aqueous media
absorbent layer positioned between said backing sheet and said top
sheet. The aqueous media impervious backing sheets may comprise any
suitable material, such as polyethylene, polypropylene and
polyurethane, preferably having a thickness of at least about 0.020
mm, which will help retain fluid within the absorbent article. The
aqueous media impervious backing sheet may also comprise a fabric
treated with a water repellent material. The aqueous media
permeable top sheets can comprise material, such as polyester,
polyolefin, rayon, and the like, that is substantially porous and
permits aqueous media to readily pass therethrough into the
underlying absorbent core. Suitable materials for both the top
sheets and the backing sheets are well known in the art.
[0029] More detailed descriptions of sanitary napkins and suitable
materials for use therein may be found in U.S. Pat. No. 3,871,378
(Duncan et al.), U.S. Pat. No. 4,324,246 (Smith et al.), and U.S.
Pat. No. 4,589,876 (Van Tillberg).
[0030] Disposable diapers comprising the hydrophilic fabrics of the
invention may be made by using conventional diaper making
techniques, replacing or supplementing the wood pulp fiber core
typically employed with the fabrics comprising hydrophilic fibers
of the present invention. The hydrophilic fibers of the invention
may also be used to input hydrophilicity to the top sheet of such
an article where hydrophilicity is desired. The hydrophilic fabrics
of this invention may thus be used in diapers in single layer or in
multiple layer core configurations. Articles in the form of
disposable diapers are described by U.S. Pat. No. 3,592,194 (Duncan
et al.), U.S. Pat. No. 3,489,148 (Duncan et al.), and U.S. Pat. No.
3,860,003 (Buell).
[0031] Preferably, a liquid composition comprising at least one
antimicrobial enhancer material and optionally a liquid vehicle is
applied by, e.g., dipping, spraying, printing, padding or by brush
or sponge, to a portion of or the entire exterior surface of the
shaped article, namely, fibers, woven and nonwoven fabrics or webs,
and batts. The liquid vehicle is then removed, typically by drying,
from the liquid composition to provide an essentially dry coating
of the antimicrobial enhancer material containing at least about 50
weight percent enhancer material, preferably at least about 75
weight percent enhancer material, and more preferably at least
about 95 wt. % enhancer material on the surface of the article. The
antimicrobial enhancer, when combined in sufficient concentration
and uniformity with a fiber prepared with the monoglyceride melt
additive, enhances either the antimicrobial activity of the article
surface or the spectrum of antimicrobial activity, that is, the
article surface has antimicrobial activity to both Gram-positive
and Gram-negative bacteria. Preferred antimicrobial enhancer
materials are organic acids and chelating agents. Examples of
suitable antimicrobial enhancer materials include: lactic acid,
tartaric acid, adipic acid, succinic acid, citric acid, ascorbic
acid, malic acid, mandelic acid, acetic acid, sorbic acid, benzoic
acid, salicylic acid, sodium acid pyrophosphate, acidic sodium
hexametaphosphate (such as SPORIX.TM. acidic sodium
hexametaphosphate and ethylenediaminetetraacetic acid or EDTA) and
salts thereof. Preferred materials are both food grade and GRAS
materials, and a particularly preferred antimicrobial enhancer
material is lactic acid. Typically, the liquid composition is
prepared by dissolving, dispersing or emulsifying the antimicrobial
enhancer material in a liquid vehicle such as water and/or a lower
alcohol, such as ethanol, to provide a liquid composition
comprising from about 1.0 to about 50 wt. % enhancer material based
on total weight of the liquid composition. A preferred method for
applying the liquid composition to extruded fibers is to spray the
hot fibers as they exit the extrusion die. Typical spray rates of
about 3 kg/hr to about 25 kg/hr of an aqueous lactic acid solution
are suitable for fiber extrusion rates of about 90 to about 100
kg/hr. Undiluted liquid lactic acid or any dilution up to a 1 part
lactic acid per 3 parts water are preferred. Solvent removal, if
necessary, can be accomplished by drying the coated fibers in an
oven.
[0032] Turning now to the drawings, in FIG. 1 there is shown an
absorbent device 10. The device has an absorbent layer 11 which is
substantially conformable and is comprised of one or more layers of
nonwoven or woven fabrics, webs or fiber batts. The layers are
comprised of fibers that are hydrophilic and, preferably, also
antimicrobial to Gram-positive bacteria, and even more preferably,
to Gram-negative bacteria as well. Where more than one layer of
fabric, web or fiber batt is employed to make the absorbent layer,
the layers may be bonded together by melt bonding (e.g., pattern
bonding or radio frequency bonding) or adhesives to form a single,
unitary layer. Suitable adhesives include hot melt spray adhesives
such as HL-1685-X or HL-1710-X, both of which are commercially
available from H.B. Fuller Co., St. Paul, Minn. The hot melt
adhesive can be applied using spiral spray adhesive systems such as
those commercially available from Nordson Corporation, Duluth, Ga.
Typical adhesive application rates using such systems are about 6
to 10 grams/m.sup.2. In addition, the fibers may be combined with
other additives commonly used to prepare absorbent fabrics or
batts, such as wood pulp, cellulose, cotton, rayon, recycled
cellulose, shredded cellulose sponge and binders. Typically, the
thickness of the absorbent layer is from about 0.5 to about 10
mm.
[0033] The absorbent layer 11 has an upper surface 12 and a lower
surface 13. Adhered to the upper surface 12 is a substantially
conformable and substantially coextensive, liquid-impermeable
backing sheet 14. The backing sheet 14 can be essentially
continuous, or it can be microporous, and preferably it is moisture
vapor-permeable so as to prevent an unacceptable buildup of
moisture within the absorbent device when the absorbent layer 11 is
saturated, for example, with wound exudate. The backing sheet 14 is
typically about 0.02 to about 0.12 mm thick, and can be selected
from a variety of commonly known polymeric films, such as
polyurethane and polypropylene films. A microporous film preferred
for use as a backing sheet can be prepared according to the method
of U.S. Pat. No. 4,726,989 (Mrozinski), and particularly the
procedure described in Examples 1-8 of that patent, without the
solvent extraction of the oil. The backing sheet 14 can be adhered
to the absorbent layer 11 by melt bonding (e.g., pattern bonding or
radio frequency bonding), or by a continuous or discontinuous
adhesive layer (not shown) comprising, for example, one of the
non-cytotoxic adhesives known in the art such as those described
above.
[0034] Optionally, a substantially conformable liquid-permeable
sheet 15 is adhered to the lower surface 13 of the absorbent layer
11. By "adhered" is meant that sheet 15 abuts and extends along the
lower surface 13 and can be, but need not be, attached thereto by
adhesive means. The liquid-permeable sheet 15 is preferably
substantially coextensive with the absorbent layer 11 and adhered
to it either by melt bonding or by an adhesive as described
hereinabove (e.g., a hot melt spray adhesive). Typically, the
liquid-permeable sheet is about 0.05 mm to about 0.075 mm thick,
and is substantially porous to permit free flow of liquid. A
particularly preferred liquid-permeable sheet is the non-stick
netting commercially available from Applied Extrusion Technologies,
Middletown, Del. as Delnet CKX215 P-S or Delnet P530-S.
[0035] Another embodiment of the absorbent device is depicted in
FIG. 2. Shown in FIG. 2 is an absorbent device 20. The device 20
has an absorbent layer 21 with an upper surface 22 and lower
surface 23. Adhered to the upper surface 22 of the absorbent layer
21 is a substantially conformable backing sheet 24. However, in
this embodiment, the backing sheet 24 is not coextensive with the
absorbent layer 21. Instead, the backing sheet 24 extends beyond
the outer perimeter of the absorbent layer 21, preferably
uniformly, to provide an extended portion 25 with a lower surface
26. The lower surface of the extended portion 25 carries an
adhesive layer 27 that can be used to adhere the absorbent device
to the target, such as the skin around a wound. The adhesive 26,
preferably a pressure sensitive adhesive, may be in the extended
portion 25 or may be covering the entire surface 22. Preferred
adhesives include adhesives having good adhesion to skin and
resistance to moisture. Examples of such adhesives are those
described in U.S. Pat. No. 5,648,166 (Dunshee).
[0036] Optionally, the device also includes a substantially
conformable, liquid-permeable sheet 29 adhered to the lower surface
23 of the absorbent layer 21. Most preferably, the liquid permeable
sheet 29 is coextensive with the absorbent layer 21. The device
also optionally includes a release liner 30 that is substantially
coextensive with and adhered to the backing sheet 24 by the
adhesive layer 27. Prior to application of the absorbent device 20
to the target, the release liner 30 is removed from the absorbent
device. Examples of suitable adhesives for adhesive layer 27
include any of the non-cytotoxic adhesives described hereinabove.
Release liner 30 can be any polymeric film, paper or foil known in
the art to be useful as a release liner. Examples of useful release
liners include 50 g/m.sup.2 basis weight SC 501FM40 white Sopal
Flexible Packaging available from Day Cedex, France. The backing
sheet 24, absorbent layer 21, and liquid permeable sheet 29 can be
the same as those elements used in the absorbent device depicted in
FIG. 1. However, moisture vapor-permeable adhesive coated films
like those described in U.S. Pat. No. 4,726,989 can also be used as
the backing sheet 24.
[0037] The invention may also find particular utility as an
antimicrobial face mask, e.g., a surgical mask, or as an
antimicrobial medical drape or gown, e.g., a surgical drape. Face
masks are used as barriers between the wearer and the environment,
and are well described in the art, e.g., in U.S. Pat. No. Re.
28,102 (Mayhew). Through their filtration efficiency, face masks
can remove particulates (organic, inorganic, or microbiological)
from the incoming or out going breath. Face masks are generally not
antimicrobially active even though they are commonly used in a
health care setting as a method of minimizing pathogen transmission
risk. The invention includes a face mask with antimicrobial
activity, that is a mask capable of killing microorganisms that
come into contact with it. This activity extends to antimicrobial
kill of such common organisms like bacteria, fungi, the influenza A
virus, and the rhinovirus, the cause of the common cold. Surgical
drapes may be constructed from single layers of a fibrous web
material or include multi-layered laminates that include one or
more film layers, e.g., as described in U.S. Pat. No. 3,809,077
(Hansen) and U.S. Pat. No. 4,522,203 (Mays). Surgical drapes
require sterilization prior to use and since the drapes generally
do not have inherent antimicrobial activity, any microbial
contamination can remain on the surface of these drapes.
[0038] The invention includes surgical drapes that can be
self-sterilizing through the application of an antimicrobial
coating to the surface of the surgical drape. Active surfaces like
the self-sterilizing surgical drapes of this invention can provide
long term antimicrobial kill of microorganisms coming in contact
with the drape surface. The following examples are offered to aid
in understanding of the present invention and are not to be
construed as limiting the scope thereof. Unless otherwise
indicated, all parts and percentages are by weight.
Glossary
Hydrocarbon Surfactants
[0039] GML: glycerol monolaurate, available from Med-Chem
Laboratories, East Lansing, Michigan under the tradename
"LAURICIDIN.TM.."
[0040] GM-C8: glycerol monocaprylate, available as POEM.TM. M-100
from Riken Vitamin LTD, Tokyo, Japan.
[0041] GM-C10: glycerol monocaprate, available as POEM.TM.-200 from
Riken Vitamin LTD., Tokyo, Japan.
[0042] GM-C12: glycerol monolaurate, prepared as follows: A 250-mL
three-necked flask equipped with thermometer, addition funnel and
nitrogen inlet adapter was charged with 100.16 g (0.5 mol) of
lauric acid (available from. Sigma-Aldrich Co., Milwaukee, Wis.)
and 0.7 g (0.5% with respect to the total weight of reactants) of
benzyl triethylammonium chloride (the catalyst, available from
Sigma-Aldrich Co.). The reaction mixture was heated to an internal
temperature of 114.degree. C. using a silicone oil bath at
119.degree. C. Next, 38.89 g (0.525 mol) of glycidol (available
from Sigma-Aldrich Co.) was added at a constant rate over 22
minutes with the internal temperature rising to a maximum of
130.degree. C. at 20 minutes. Within 1.5 hours, the temperature of
the reaction had fallen to 113.degree. C. At 6.5 hours, the
reaction was stopped and 134.19 g of product was isolated. The
product was analyzed by .sup.1H and .sup.13CNMR spectroscopy, and
the ratios of products were established by assignment and
quantitative integration of the glycerol carbons.
[0043] GM-C14: glycerol monomyristate, prepared as follows: Using a
procedure similar to that described for the preparation of GM-C12,
114.19 g (0.5 mol) of myristic acid (available from Sigma-Aldrich
Co.), 38.9 g (0.525 mol) of glycidol, and 0.77 g of benzyl
triethylammonium chloride were reacted for 18 hours to provide
143.5 g of product.
[0044] GM-C16: glycerol monopalmitate, prepared as follows: Using a
procedure similar to that described for the preparation of GM-C12,
89.75 (0.35 mol) of palmitic acid (available from Sigma-Aldrich
Co.), 27.22 g (0.3675 mol) of glycidol, and 0.58 g of benzyl
triethylammonium chloride were reacted for 6 hours to provide 114.4
g of product.
[0045] GM-C18: glycerol monostearate, prepared as follows: Using a
procedure similar to that described for the preparation of GM-C12,
142.24 (0.5 mol) of stearic acid (available from Sigma-Aldrich
Co.), 36.67 (0.495 g mol) of glycidol, and 0.895 g of benzyl
triethylammonium chloride were reacted for 18.5 hours to provide
approximately 170 g of product.
[0046] GM-C18D: glycerol monostearate, prepared as follows: An
aliquot of about 60 g of GM-C18 was distilled using a single plate
distillation at a head temperature of 240.degree. C. at 0.5 torr to
provide about 25 g of distillate.
[0047] HS-1: glycerol monococoate, available as LUMULSE.TM. GML
from Lambert Technologies, Skokie, Ill.
[0048] HS-2: glycerol monooleate, available as LUMULSE.TM. GMO from
Lambert Technologies.
[0049] HS-3: glycerol monostearate, available as EMEREST.TM. 2400
from Henkel Corp., Organic Products Division, Charlotte, N.C.
[0050] HS-4: glycerol monoisostearate, prepared as follows: A 1-L
3-necked round bottom flask equipped with heating mantle, stirrer,
thermometer, and Dean-Stark apparatus was charged with 284.48 g (1
mol) of isostearic acid (available as EMEREST.TM. 873 from Henkel
Corp.), 92.09 g (1 mol) of glycerol, 2.26 g of p-toluenesulfonic
acid (available from Sigma-Aldrich Chemical Co., Milwaukee, Wis.),
and 131.8 g of toluene. The resulting mixture was stirred and
heated overnight, using Dean-Stark conditions, was allowed to cool
to 80.degree. C., was neutralized with 1.75 g of triethanolamine,
and was filtered through a Buchner funnel containing a pad of
CELITE.TM. filtering medium (available from Aldrich Chemical Co.,
Milwaukee, Wis.). The filtrate was concentrated by removing solvent
at 150.degree. C. and 40 torr pressure to provide an amber liquid
product.
[0051] HS-5: PEG 600 dioleate, available as MAPEG.TM. 600D0 from
BASF Corp., Specialty Chemicals; Mount Olive, N.J.
[0052] HS-6: PEG 400 monotallate, available as MAPEG.TM. 400MOT
from BASF Corp., Specialty Chemicals.
[0053] HS-7: ethoxylated (9.5) octylphenol, available as TRITON.TM.
X-100 from Union Carbide Corp, Danbury, Conn.
[0054] HS-8: polyoxyalkylene (10) oleyl ether, available as
BRIJ.TM. 97 from ICI Surfactants, Wilmington, Del.
[0055] HS-9: a phenoxyaryl alkyl ethoxylate, available as
EMULVIN.TM. from Bayer Corp., Pittsburgh, Pa.
[0056] SPAN.TM. 20: sorbitan monolaurate, 100% active, having an
HLB of 8.6, available from Uniquma (ICI Surfactants), Wilmington,
Del.
[0057] SPAN.TM. 40: sorbitan monopalmitate, 100% active, having an
HLB of 6.7, available from Uniquma (ICI Surfactants), Wilmington,
Del.
[0058] ARLACEL.TM. 60: sorbitan monostearate, 100% active, having
an HLB of 4.3, available from Uniqema (ICI Surfactants).
[0059] ARLACEL.TM. 83: sorbitan sequioleate (11/2 mole adduct),
100% active, having an HLB of 3.7, available from Uniqema (ICI
Surfactants).
Fluorochemical Surfactants
[0060] FS-1: a hydrophilic fluorochemical polymer melt additive for
nonwovens, available as 3M.TM. FC-1802 Protective Chemical from 3M
Company, St. Paul, Minn.
[0061] FS-2: MeFOSA/TRITON.TM. X-100 adduct, made by the
condensation reaction of TRITON.TM. X-100 chloride with MeFOSA
amide (C.sub.8F.sub.17SO.sub.2NH.sub.2) as follows:
[0062] First, TRITON.TM. X-100 chloride was made according to the
following procedure: To a 3-necked round bottom flask equipped with
overhead stirrer, thermometer, reflux condenser and two attached
gas washing bottles (the second bottle containing a 10% aqueous
solution of sodium hydroxide) was charged 646 g (1.0 mol) of
TRITON.TM. X-100 and 12.9 g of CELITE.TM. filtering medium. The
resulting mixture was heated to 60.degree. C., then 142.76 g (1.2
mol) of thionyl chloride was added via an addition funnel over a
period of about 22 minutes, raising the reaction mixture
temperature to 75.degree. C. Then nitrogen was bubbled through the
reaction mixture for 4 hours, during which time the mixture
temperature varied from 68-71.degree. C. The reflux condenser and
gas washing bottles were replaced by a still head, and the reaction
mixture was stirred while a vacuum of about 50 torr absolute
pressure was applied. After the reaction was shown to be complete
by .sup.13C and .sup.1H NMR analysis, the reaction mixture was
filtered hot through a C-porosity fitted glass Buchner funnel to
yield a light yellow product, TRITON.TM. X-100 chloride.
[0063] The TRITON.TM. X-100 chloride was then reacted with MeFOSA
using the following procedure. To a 3-necked round bottom flask
equipped with overhead stirrer, reflux condenser and nitrogen inlet
adapter was charged 125 g (0.244 eq) of MeFOSA (which can be made
as described by Brice et al. in U.S. Pat. No. 2,732,398), 177.80 g
of TRITON.TM. X-100 chloride, 30.18 (0.2794 eq) of sodium carbonate
and 2.46 g (0.0149 eq) of potassium iodide. The resulting reaction
mixture was heated to 120.degree. C. for 8 hours, at which time the
MeFOSA had disappeared according to gc analysis. After cooling to
95.degree. C., the reaction mixture was washed with 157 g of 10%
aqueous sulfuric acid, followed by 157 g of deionized water. The
washed reaction mixture was concentrated by evaporation on a rotary
evaporator at 70.degree. C. and 50 torr absolute pressure to give
252.6 g of a brown liquid (92.2% yield). The structure of the
desired product was confirmed by .sup.13C and .sup.1H NMR
spectroscopy.
Silicone Surfactant
[0064] SS-1: NUWET.TM. 500 silicon ethoxylate, available from Osi
Specialties, Inc., Danbury, Conn.
Thermoplastic Polymers
[0065] PP 3505: ESCORENE.TM. PP3505 polypropylene, having a 400
melt index flow rate, available from Exxon Chemical Co., Baytown,
Tex.
[0066] PP 3746: ESCORENE.TM. PP3746 polypropylene, having a 1400
melt index flow rate, available from Exxon Chemical Co.
[0067] EOD 96-36: FINA.TM. EOD-96-36 polypropylene, having a 750
melt flow index, available from Fina Corp., La Porte, Tex.
[0068] 3960X: FINA.TM. 3960X polypropylene, having a 350 melt flow
index, available from Fina Corp., LaPorte, Tex.
[0069] 3155: EXXON.TM. 3155 polypropylene, having a 35 melt flow
index, available from Exxon Chemical co.
[0070] 4023: EXACT.TM. 4023 ethylene/butylene copolymer, containing
a majority by weight of ethylene, available from Exxon Chemical
Co.
[0071] PB 0400: MONTELL.TM. 0400 1-butylene homopolymer, having a
20 nominal melt index, available from Montell, Houston, Tex.
[0072] DP-8910: MONTELL.TM. DP-8910 polybutylene, containing
peroxide, available from Montell.
[0073] DP-8340: MONTELL.TM. DP-8340 1-butylene/ethylene copolymer,
having a melt flow index of 35, available from Montell.
[0074] 8401: ENGAGE.TM. 8401, an ethylene/octene copolymer
containing 19% octene by weight, having a melt flow index of 30,
available from DuPont Dow Elastomer.
[0075] 8402: ENGAGE.TM. 8402, an ethylene/octene copolymer
containing 13.5% octene by weight, having a melt flow index of 30,
available from DuPont Dow Elastomer.
Antimicrobial Enhancer Material
[0076] LA: Lactic acid, USP, commercially available from J. T.
Baker, Phillipsburg, N.J.
Analyses and Test Methods
[0077] Analyses and Calculated Hydrophilic-Lipophilic Balance (HLB)
Values of Glycerol Monoesters
[0078] Table 1 provides the weight percent of monoglycerides,
diglycerides, triglycerides, and glycerol present in a number of
the materials described in the glossary. The mole percent values of
the materials were established by assignment and quantitative
integration of the glycerol carbons in the .sup.13C NMR spectrum of
each material, and the mole percent values were translated into
weight percent values. The amounts of 1- and 2-substituted
monoglycerides as well as the amounts of the 1,2- and
1,3-diglycerides were combined to determine, respectively, the
weight percent fractions of monoglycerides, and diglycerides
presented in the table.
[0079] Also presented in Table 1 are calculated HLB values for each
material. The HLB values for each monoglyceride, diglyceride and
triglyceride present in the materials were calculated using a group
contribution method. The HLB value for glycerol was also
calculated. In this method, HLB values are derived using the
relation:
HLB=7+.SIGMA. (hydrophilic group number)-.SIGMA.(hydrophobic group
number).
The group numbers for the particular monoglycerides, diglycerides
and triglycerides as well as glycerol are given in Tables I-IV on
page 374 of the reference: J. T. Davies and E. K. Rideal,
Interfacial Phenomena, Second Edition, Academic Press, London,
1963.
[0080] The HLB value for each material was then calculated using
the weight fraction of glycerol and each monoglyceride, diglyceride
and triglyceride component in the material using the following
equation:
HLB mixture=(wt. fraction monoglyceride).times.(HLB
monoglyceride)+(wt. fraction diglyceride).times.(HLB
diglyceride)+(wt. fraction triglyceride).times.(HLB
triglyceride)+(wt. fraction glycerol).times.(HLB glycerol)
TABLE-US-00001 TABLE 1 Monoglyceride # Carbons in Calculated
Glossary Component of Monoglyceride Monoglycerides Diglycerides
Triglycerides Glycerol Weight % HLB Designation Surfactant Fatty
Acid (wt. %) (wt. %) (wt. %) (wt. %) Total Mixture GM-C8 Glycerol 8
88.8 7.4 0.0 3.8 100 8.3 monocaprylate GM-C10 Glycerol 10 89.1 6.5
0.0 4.4 100 7.4 monocaprate GML Glycerol 12 94.0 5.7 0.0 0.3 100
6.3 monolaurate GM-C12 Glycerol 12 90.5 8.3 0.0 1.1 100 6.2
monolaurate HS-1 Glycerol 12 44.5 38.0 .3 8.3 100 4.3 monococoate
GM-C14 Glycerol 14 88.4 6.8 1.2 3.6 100 5.3 monomyristate GM-C16
Glycerol 16 93.8 4.3 0.0 1.8 100 4.5 monopalmitate GM-C18 Glycerol
18 87.7 6.4 2.7 3.2 100 3.0 monostearate GM-C18D Glycerol 18 92.3
4.5 0.0 3.2 100 3.6 monostearate HS-3 Glycerol 18 56.5 35.1 2.0 6.4
100 1.2 monostearate HS-2 Glycerol 18 50.9 41.1 4.2 3.9 100 0.2
monooleate
Effective Fiber Diameter (EFD) Measurement
[0081] EFD measurements were made according to the procedure
outlined in Davies, C.N., "The Separation of Airborne Dust and
Particles", Institute of Mechanical Engineers, London, Proceedings
1B, 1952.
Melt-Blown Extrusion Procedure A
[0082] This melt-blown extrusion procedure was the same as
described in U.S. Pat. No. 5,300,357 (Gardiner), at column 10. A
Brabender 42 mm conical twin screw extruder was used, with a
maximum extrusion temperature of 255.degree. C. and distance to the
collector of 12 inches (30 cm). Monoglyceride and polypropylene
mixtures were prepared by blending the monoglyceride and
polypropylene in a paperboard container using a mixer head affixed
to a hand drill for about one minute until a visually homogeneous
mixture was obtained. The process condition for each mixture was
the same, including the melt blowing die construction used to blow
the microfiber web. The basis weight of the resulting webs, unless
otherwise stated, was 50.+-.5 g/m.sup.2 (GSM), and the targeted
diameter of the microfibers was 7 to 12 micrometers. The width of
the web was about 12 inches (30.5 cm). Unless otherwise stated, the
extrusion temperature was 255.degree. C., the primary air
temperature was 258.degree. C., the pressure was 124 KPa (18 psi),
with a 0.076 cm air gap width, and the polymer throughput rate was
about 180 g/hr/cm.
[0083] The measured average effective fiber diameter for each type
of polymer used in the Examples was as follows: [0084] PP 3505: 7.5
to 12.0 microns [0085] EOD 96-36 polypropylene: 7.4 to 11.4
microns
Melt-Blown Extrusion Procedure B
[0086] This Procedure B is basically the same as Procedure A
described above, except that the extrusion temperature was 280 to
350.degree. C., the polymer throughput rate was about 66 kg/hr, and
the monoglyceride was incorporated into the polymer melt stream
just before the die, as described in U.S. Pat. No. 4,933,229
(Insley et al.) and U.S. Pat. No. 5,064,578 (Insley et al.). The
monoester throughput rate was about 2 kg/hr and the die width was
about 152 cm.
Spunbond Extrusion Procedure
[0087] The extruder used was a Reifenhauser Extruder Model Number
RT 381 (available from Reifenhauser Co., Troisdorf, Nordrheim
Westfalen, Germany), 2.34 m in length.times.1.335 m in
width.times.1.555 m in height, weighing 2200 kg. The extruder was
driven by an infinitely variable shunt wound DC motor, 37.3 kW and
2200 rev/min max. The maximum screw speed was reduced to 150
rev/min. The screw was 70 mm in diameter and 2100 mm in length. The
extruder had five 220 V heating zones using a total of 22.1 kW of
heating power. The metering pump delivered 100 cm.sup.3 of polymer
melt per revolution. The die had seven adjacent heating zones. The
spinneret was approximately 1.2 meters wide and had 4036 holes,
each hole of 0.6 mm diameter and 2.4 mm in length. The extrusion
temperature reported was the temperature in the die block before
the polymer melt stream was distributed along the die. The maximum
throughput of the die was 104 kg/h, or 0.43 g/hole/min. The cooling
chamber operated with an air temperature of 18.3.degree. C. and a
cooling air speed of 1000 to 3000 m/min.
[0088] The bonder used to bond the spunbond fibers into a fabric
was a Kusters Two-Bowl-Thermobonding-Calender (available from
Kusters Corp., Nordrheim Westfalen, Germany). The effective bonding
width was 1.2 m. The upper patterned metal roll had a 14.66%
bonding area and a temperature of 270-285.degree. F.
(132-141.degree. C.), while the lower rubber roll had a slick
surface and a temperature of 265-280.degree. F. (129-138.degree.
C.). The bonding nip pressure was 57-750 pounds force per linear
inch (3000-41000 J/cm). The heating of the rolls was done by
convection from a continuously circulating furnace oil. The
temperature of the nips was 200-300.degree. F. (93-149.degree. C.).
The speed of the bonder was directly synchronized to the speed of
the collection belt that had a range of 3.6 to 65 linear meters per
minute.
[0089] The basis weight for each nonwoven fabric (g/m.sup.2) was
calculated by multiplying the speed of the spin pump (rev/m) times
the constant 71. For all examples, the basis weight used was
approximately 20 g/m.sup.2.
Hydrophilicity Test
[0090] The Hydrophilicity Test was run by holding the outside
surface (side opposite the collector) a rectangular nonwoven web
sample approximately 8.times.11 inches (20.times.28 cm) under a
stream of either hot (approximately 45.degree..+-.2.degree. C.) or
cold (approximately 25.degree..+-.2.degree. C.) tap water with a
volume output of approximately 200 ml/min at a distance of about 1
inch (2.5 cm) from the water spigot. The nonwoven web sample was
held with thumbs downward on top of the center of each 8 inch (20
cm) side edge and fingers upward underneath the web sample pointed
toward the center of the sample for support, and tilting the web
slightly so that the far 11 inch (28 cm) edge was slightly higher
than the near 11 inch (28 cm) edge. Each nonwoven web sample had a
basis weight of 50.+-.5 g/m.sup.2, an effective fiber diameter of 8
to 13 microns (as calculated according to the method set forth in
Davies, C. N., "The Separation of Airborne Dust and Particulates,"
Institution of Mechanical Engineers, London, Proceedings 1B, 1952),
and a web solidarity of 5 to 15%. The following number scale was
used to rate the hydrophilicity of each web sample: [0091] 1
immediate wetting (web sample goes from being completely opaque to
completely translucent); [0092] 2 wetting delayed for about 0.5 to
2.0 seconds (web sample goes from being completely opaque to
completely translucent); [0093] 3 wetting delayed from greater than
2.0 seconds to about 10 seconds (web sample goes from being
completely opaque to completely translucent); [0094] 4 wetting
delayed from greater than 2.0 seconds to about 10 seconds, but
wetting occurs only where the web sample contacts the hand placed
under the sample; [0095] 5 no wetting at all (i.e., the web sample
remains opaque). Where the degree of wetting varied across the
width of the web sample, a set of several number values was
recorded, representing values measured in a direction perpendicular
to the machine direction from one side of the web sample to the
other. For example, in one case, the first 40% of the distance
across the web sample showed a reading of "1", the next 20% of the
distance across the web sample showed a reading of "5", and the
final 40% of the distance across the web sample showed a reading of
"2". The reported rating for this web would be the weighted average
of the values or (0.40)(1)+(0.20)(5)+(0.40)(2)=2.2.
[0096] A value (either single or weighted average) of no greater
than 3 for both hot and cold water is preferred.
Percent Wet Pickup Test
[0097] A 12 inch (30 cm) long.times.8 inch (20 cm) wide by 2 inch
(5 cm) deep pan was filled with 2 liters of tap water having a
temperature of 25.+-.2.degree. C. Nonwoven melt blown fabric web
samples having a target basis weight of 9 to 10 grams per square
meter were each cut to a rectangular shape of 6.5.+-.0.5 inches by
11.5.+-.1 inch and weighed 2.4.+-.0.3 grams. Each rectangular web
sample was weighed to the nearest hundredth gram on a balance to
give the Fabric Dry Weight. The web sample was placed flat upon the
water surface for 5.+-.2 seconds, then was removed from the water
surface and was allowed to drip excess water for 5.+-.2 seconds.
The wetted, drained web sample was weighed again to the nearest
0.01 gram to give the Fabric Wet Weight. The Percent Wet Pickup was
calculated using the formula:
Percent Wet Pickup = ( Fabric Wet Weight - Fabric Dry Weight )
Fabric Dry Weight .times. 100 ##EQU00001##
The test was repeated on five different samples for each test web,
so that each Percent Wet Pickup value reported is the average of
five replications. The standard deviation is given for each set of
five replications.
Percent Water Absorbency Test
[0098] Evaluation of the percent water absorbency of various
materials of this invention was measured using the following test
procedure. For each test, a 7.62 cm.times.7.62 cm sample having a
target basis weight of 9 to 10 grams per square meter was weighed,
placed on the surface of tap water at 32.degree..+-.2.degree. C.
for one minute, and then removed from the surface of the water by
holding up a corner of the pad with the smallest possible area.
When the sample used was a pad having a waterproof side, the
absorbent side (i.e., netting side) of the pad was placed down on
the water surface. The excess water was allowed to drip off from
one corner of the pad for 30.+-.2 seconds, still holding a corner
of the pad with the smallest possible area. The sample was then
weighed again. The percent water absorbency of the sample was then
calculated using the formula:
Percent Water Absorbancy = ( Wet Sample Weight - Dry Sample Weight
) Dry Sample Weight .times. 100 ##EQU00002##
[0099] Each Percent Water Absorbency reported value is the average
of 8-10 replications.
Drop Wetting Test
[0100] The hydrophilicity of the outside surface (side opposite the
collector belt) of spunbond fabrics was measured using the
following drop wetting test procedure. A 10 cm by 20 cm piece of
spunbond fabric, having a basis weight of approximately 20
g/m.sup.2 unless otherwise noted, was placed on a double folded
paper towel, and the fabric was smoothed by hand to be in as
intimate contact as possible with the paper towel. Next, 10 drops
of 0.9% aqueous NaC1 having a temperature of 25.+-.3.degree. C. and
about 6-8 mm in diameter were gently placed on the fabric at least
8 mm apart. After 10 seconds, the number of drops that are
completely absorbed from the surface of the nonwoven into the paper
towel was recorded. Values provided in the examples are each an
average of three such drop absorption trials.
Antimicrobial Test
[0101] The materials of this invention were cut into 3.8
cm.times.3.8 cm square samples and evaluated for antimicrobial
activity according to the American Association of
[0102] Textile and Color Chemists (AATCC) Test Method 100-1993, as
published in the AATCC Technical Manual, 1997, pages 143-144.
Modifications to the Test Method included the use of Tryptic Soy
Broth as the nutrient broth and for all dilutions and Tryptic Soy
Agar as the nutrient agar. Letheen Broth (VWR Scientific Products,
Batavia, Ill.) was used as the neutralizing solution.
EXAMPLES
Examples 1-13 and Comparative Examples C1-C15
[0103] In Examples 1 to 7, the initial wettability of nonwoven webs
prepared using Melt-Blown Extrusion Procedure A to extrude EOD
96-36 polypropylene with various melt additives was determined.
[0104] Examples 1 to 7 were prepared using concentrations of GML
varying from 1 to 4% by weight (based on polymer weight). Examples
8-13 were prepared using various monoglycerides of relatively high
purity at 3% by weight. Comparative Example C1 was prepared using
glycerol monostearate at 3% by weight. Comparative Examples C5 to
C8 were prepared using less pure grades of glycerol monoesters.
Comparative Examples C2 and C3 were prepared using different
fluorochemical nonionic surfactants and Comparative Example C4 was
prepared using a silicone surfactant. Comparative Examples C9 to
C13 were prepared using various other hydrocarbon surfactants,
including PEG di- and monoesters, an alkylphenol ethoxylate, an
alcohol ethoxylate, and a phenoxy aryl alkylphenol ethoxylate.
Comparative Examples C14 and C15 were prepared without a melt
additive. It should be noted that Examples 8-10 and Comparative
Example C15 were prepared using the same Melt-Blown Extrusion
Procedure A outlined above, but at an extrusion temperature of
220.degree. C. instead of 255.degree. C. A rating of hydrophilicity
for each nonwoven web was determined using the Hydrophilicity Test.
A description of the samples and their Hydrophilicity Test results
are summarized in Table 2.
[0105] Also included in Table 2 is an analysis of weight percent
monoglyceride, where applicable, for each additive.
TABLE-US-00002 TABLE 2 Surfactant 1 Monoglyceride in Cold Water Hot
Water Ex. (wt. %) Surfactant 1 (wt. %) Rating Rating 1 GML (1.0%)
94 5.0 3.4 2 GML (1.25%) 94 4.4 1.9 3 GML (1.5%) 94 2.3 1.3 4 GML
(2.0%) 94 1.4 1.0 5 GML (2.5%) 94 1.3 1.0 6 GML (3.0%) 94 1.0 1.0 7
GML (4.0%) 94 1.0 1.0 8* GML (3.0%) 94 1.0 1.0 9* GM-C8 (3.0%) 88.8
1.7 1.4 10* GM-C10 (3.0%) 89.1 1.0 1.0 11 GM-C12 (3.0%) 90.5 1.2
1.0 12 GM-C14 (3.0%) 88.4 2.7 1.0 13 GM-C16 (3.0%) 93.8 4.4 1.0 C1
GM-C 18 (3.0%) 87.0 5.0 3.2 C2 FS-1 (1.25%) N/A 1.0 1.0 C3 FS-2
(1.25%) N/A 3.0 1.0 C4 SS-1 (3.0%) N/A 5.0 3.0 C5 HS-1 (3.0%) 44.5
5.0 4.6 C6 HS-2 (3.0%) 50.9 5.0 5.0 C7 HS-3 (3.0%) 56.5 5.0 5.0 C8
HS-4 (3.0%) N/M 5.0 5.0 C9 HS-5 (3.0%) N/A 5.0 5.0 C10 HS-6 (3.0%)
N/A 5.0 3.3 C11 HS-7 (3.0%) N/A 5.0 5.0 C12 HS-8 (3.0%) N/A 5.0 4.0
C13 HS-9 (3.0%) N/A 5.0 5.0 C14 -- N/A 5.0 5.0 C15* -- N/A 5.0 5.0
N/M: means not measured N/A: means not applicable because material
did not contain monoglyceride *means extruded at 220.degree. C.
rather than the usual 270-280.degree. C.
[0106] The data in Table 2 show that samples prepared using GML
provided good wettability even at GML levels as low as 1.5% in the
polymer. At the 3% level, excellent wettability to both cold and
hot water resulted, and the overall performance of the sample
favorably compared to samples prepared using FS-1, a more expensive
hydrophilic fluorochemical additive. Even at some levels less than
3%, GML outperformed SS-1, a hydrophilic silicone surfactant.
[0107] The data also show that materials containing monoglycerides
derived from C.sub.8, C.sub.10, C.sub.10, C.sub.12, C.sub.14 and
C.sub.16 carboxylic acids (HLB values of 8.3, 7.4, 6.3, 6.2, 5.3
and 4.5 respectively) also imparted improved wettability to
nonwoven webs. However, materials containing monoglycerides derived
from C.sub.18 carboxylic acid provided only slightly better hot
water wetting than the control.
[0108] The effect of the concentration of monoglyceride in the
surfactant material is illustrated by comparing Examples 6 and 11
(prepared from GML and GM-C12, which have glycerol monolaurate
contents of 94 and 90.5% and calculated HLB values of 6.3 and 6.2,
respectively) with Comparative Example C5 (prepared with HS-1
having a glycerol monolaurate content of 44.5% and a calculated HLB
value of 4.3). The samples shown in Examples 6 and 11 provided
improved wettability over the control. However, the Comparative
Example C5 sample did not. In part, this was attributable to the
lower concentration of monoglyceride in the Comparative C5 sample.
Also, even quite pure materials, like GM-C18 (87% glycerol
monomyristate, HLB value of 3.0), are not as effective at imparting
wettability to the nonwoven web as monoglycerides derived from
carboxylic acids with optimum chain lengths. Thus, the HLB value
which accounts for both monoglyceride content and type of
monoglyceride can be an excellent predictor of whether commercially
available monoglyceride, diglyceride, triglyceride and glycerol
mixtures will function at the concentrations most desired for cost
effectiveness and processability. The data show that additive
materials containing monoglycerides and having HLB values of about
4.5 to 9.0 will improve wettability over the control.
[0109] HS-5 and HS-6 which are mixtures of di- and mono-fatty acid
esters of polyethylene glycol, did not significantly improve the
wettability of nonwoven webs over the control.
Examples 14 to 18 and Comparative Examples C16 to C20
[0110] In Examples 14 to 18 and Comparative Examples C16 to C20,
polybutylene (PB 0400) was evaluated as a hydrophilic enhancer for
various hydrocarbon surfactants. In all Examples and Comparative
Examples, polypropylene EOD 96-36 and the Melt-Blown Extrusion
Procedure A were used to prepare the nonwoven web samples and the
Hydrophilicity Test was used to evaluate the initial wettability of
each of the nonwoven webs.
[0111] A description of the samples and their results from the
Hydrophilicity Test are presented in Table 3.
TABLE-US-00003 TABLE 3 Hydrocarbon PB 0400 Cold Water: Hot Water:
Ex. Surfactant (wt. %) (wt. %) Rating Rating 14 GML (1.0%) 5 3.6 1
14 GML (1.0%) -- 5 3.4 control 15 GML (1.5%) 5 1 1 15 GML (1.5%) --
2.3 1.3 control 16 GML (2.0%) 5 1 1 16 GML (2.0%) -- 1.4 1 control
C16 HS-1 (1.5%) + HS-7 5 5 4.8 (1.5%) C16 HS-1 (1.5%) + HS-7 -- 5 5
Control (1.5%) C17 HS-3 (1.5%) + HS-7 5 5 2.9 (1.5%) C17 HS-3
(1.5%) + HS-7 -- 5 4.4 Control (1.5%) C18 HS-1 (3.0%) 5 5 2.3 C18
HS-1 (3.0%) -- 5 4.3 Control 17 GM-C12 (2.0%) 5 1 1 18 GM-C14
(3.0%) 5 2 1 C19 GM-C 18D (2.0%) 5 4.5 2 C20 HS-7 (3.0%) -- 5 5
Control C20 HS-7 (3.0%) 5 5 5
[0112] The data in Table 3 show that polybutylene enhanced the
wettability of the polypropylene webs containing glycerol
monoesters with HLB values ranging from 5.3 to 8.3 versus the
controls (no polybutylene). Polybutylene did not significantly
enhance wettability when combined with glycerol monoesters having
HLB values of less than 5 in combination with an ethoxylated
alkylphenol surfactant. Polybutylene also did not enhance the
wettability of webs prepared using only an ethoxylated octylphenol
surfactant.
Re-Testing of Selected Webs from Tables 1 and 2 after Aging at Room
Temperature
[0113] The nonwoven webs from Examples 6, 8, 10, 14, 15, 16 and 17
were reevaluated for wettability using the Hydrophilicity Test
after aging under ambient lab conditions for a period of 4-5 months
(also after 2 months for Examples 6 and 15). The wetting values,
initially and after aging, are presented in Table 4.
TABLE-US-00004 TABLE 4 Cold Water (initial and Hot Water (initial
Hydrocarbon PB 0400 after aging) and after aging) Ex. Surf. (wt. %)
(wt. %) Init. 2 mos. 4-5 mos Init. 2 mos. 4-5 mos. 6 GML (3.0%) --
1 3 4 1 1 1 8* GML (3.0%) -- 1 N/R 5 1 N/R 1 10* GM-C10 -- 1 N/R 3
1 N/R 1 (3.0%) 14 GML (1.0%) 5.0 3.6 N/R 4 1 N/R 1 15 GML (1.5%)
5.0 1 4 4 1 1 1 16 GML (2.0%) 5.0 1 N/R 4 1 N/R 1 17 GM-C12 5.0 1
N/R 5 1 N/R 1 (2.0%) *means extruded at 220.degree. C. rather than
the usual 270-280.degree. C. N/R: means not recorded
[0114] The data in Table 4 show that the wettability of the
polypropylene webs to cold water decreased after storage for 4-5
months, even when polybutylene was present.
Examples 19-23 and Comparative Examples C21-C23
[0115] A series of experiments was run to investigate the effect of
using SPAN.TM. 20 (sorbitan monolaurate) or SPAN.TM. 40 (sorbitan
monopalmitate) in combination with GML and polypropylene to improve
the hydrophilicity of the extruded webs after aging. In all
Examples and Comparative Examples, polypropylene EOD 96-36 and the
Melt-Blown Extrusion Procedure A were used to prepare the nonwoven
web samples and the Hydrophilicity Test was used to evaluate the
wettability of each nonwoven web, both initially and after aging
for 23 days under ambient conditions.
[0116] Results from the Hydrophilicity Test are presented in Table
5.
TABLE-US-00005 TABLE 5 Cold Hot Water Water: After After wt %:
Aging Aging Ex. wt % GML Span 20 Span 40 Init. 23 days Init. 23
days C21 -- -- -- 5 5 5 5 19 3 -- -- 1 4 1 1 20 2.25 0.75 -- 1 1 1
1 21 1.5 1.5 -- 5 2.7 1 1 C22 -- 3.0 -- 5 4 1.7 1 22 2.25 -- 0.75 1
1 1 1 23 1.5 -- 1.5 2.7 1 2 1 C23 -- -- 3.0 5 3.3 5 4
[0117] The data in Table 5 show that GML in combination with either
SPAN.TM. 20 or SPAN.TM. 40 produced nonwoven webs with superior
hydrophilicity after aging. Optimum hydrophilicy before and after
aging occurred at 25% replacement of the GML with either SPAN.TM.
20 or SPAN.TM. 40. Also, SPAN.TM. 20 and SPAN.TM. 40 acted as an
extender, allowing for 25% substitution of the more expensive GML
component.
Examples 24-32 and Comparative Examples C24-C25
[0118] A series of experiments was run to investigate mixtures of
PB 0400 polybutylene, various sorbitan esters, and GML as polymer
melt additives for polypropylene. In all Examples and Comparative
Examples, polypropylene EOD 96-36 and the Melt-Blown Extrusion
Procedure A were used to prepare the nonwoven web samples, and the
Hydrophilicity Test was used to evaluate the wettability of each
nonwoven web, both initially and after aging under ambient
conditions. The web samples containing SPAN.TM. 20 (sorbitan
monolaurate) were aged for 10 days at room temperature, while the
web samples containing ARLACEL.TM. 60 (sorbitan monostearate) and
ARLACEL.TM. 83 (sorbitan sequioleate) were aged for 7 days at room
temperature.
[0119] Results from the Hydrophilicity Test are presented in Table
6.
TABLE-US-00006 TABLE 6 Sorbitan Ester (SPAN .TM./ Cold Hot ARLACEL
.TM.): PB0 Water: Water: GML Product 400 After After Ex. wt %
Number wt % wt % Init. Aging Init. Aging 24 1.8 20 0.2 -- 1.7 3.7 1
1 25 1.8 20 0.2 5 1 3 1 1 26 1.4 20 0.6 -- 1.7 3.7 1 1.7 27 1.4 20
0.6 5 1 2 1 1 28 2.1 20 0.9 -- 1 3 1 1 29 2.1 20 0.9 5 1 2 1 1 30
1.05 60 0.45 5 3.3 4 1 1 C24 -- 60 1.5 5 5 5 5 5 31 1.05 83 0.45 5
3.3 4 1 1 C25 -- 83 1.5 5 3.7 5 2 2 32 1.05 20 0.45 11.58 1 N/R 1
N/R 32A 0.975 20 0.525 7.5 2 N/R 1.2 N/R 32B 0.975 20 0.525 3.5 3.7
N/R 3 N/R 14 1 -- -- 5 3.6 -- 1 -- N/R = not run
[0120] The data in Table 6 show that the addition of 5%
polybutylene to blends of GML and SPAN.TM. 20 generally improved
the cold water hydrophilicity of the web, both before and after
aging. Neither ARLACEL.TM. 60 or ARLACEL.TM. 83 appeared to offer
any particular benefit when incorporated with the GML (compare
initial results from Examples 30 and 31 with Example 14 included
for reference). GML levels could be reduced to nearly 1% when the
PB 0400 level was increased to greater than 10% and the SPAN.TM. 20
level was under 0.5% (Example 32).
[0121] The aged webs from Example 30 and Comparative Example C24
were tested again according to the Hydrophilicity Test after aging
for a total of about 7 months. Hot water values were 2 and 5,
respectively, while cold water values were 5 and 5,
respectively.
Examples 33-49 and Comparative Example C26
[0122] A series of experiments was run to investigate the optimum
weight ratio of GML to SPAN.TM. 20 or SPAN.TM. 40 when used in
conjunction with 5% PB 0400 polybutylene as a polymer melt additive
to polypropylene. In all Examples and the Comparative Example,
polypropylene EOD 96-36 and the Melt-Blown Extrusion Procedure A
were used to prepare the nonwoven web samples and the
Hydrophilicity Test was used to evaluate the wettability of each
nonwoven web, both initially and after aging for 10 days under
ambient conditions.
[0123] Results from the Hydrophilicity Test are presented in Table
7.
TABLE-US-00007 TABLE 7 GML + SPAN .TM. GML to Cold Water: Hot
Water: SPAN .TM. monoester SPAN .TM. After After monoester Product
monoester PB 0400 Aging Aging Ex. wt % No. Ratio wt % Init. 10 days
Init. 10 days C26 -- -- -- -- 5 5 5 5 33 3 -- infinite -- 1 3.8 1 1
34 2 20 90/10 5 1 3.8 1 1 35 2 20 70/30 5 1 1 1 1 36 1.75 20 90/10
5 1 5 1 1 37 1.75 20 50/50 5 1 1 1 1 38 1.5 20 70/30 5 1 1 1 1 39
1.5 20 50/50 5 1 1 1 1 40 1 20 90/10 5 1 4 1 1 41 1 20 70/30 5 1 1
1 1 42 1 20 50/50 5 1 1 1 1 43 2 40 90/10 5 1 2 1 1 44 2 40 50/50 5
3 4 1 1 45 1.75 40 90/10 5 1 2.7 1 1 46 1.75 40 70/30 5 1 3 1 1 47
1.5 40 90/10 5 1 4 1 1 48 1.5 40 70/30 5 1 1.7 1 1 49 1.5 40 50/50
5 2 2.7 1 1
[0124] The data in Table 7 shows that, in a 1-2% concentration
range of GML plus SPAN.TM. 20 monoester, replacement of GML with
10% of SPAN.TM. 20 monoester does not greatly improve the cold
water hydrophilicity after aging of the meltblown webs. However,
replacement of GML with 30% or 50% of SPAN.TM. 20 monoester clearly
enhances the cold water hydrophilicity after aging of the webs.
Additionally, SPAN.TM. 20 monoester is more effective than SPAN.TM.
40 monoester in improving the cold water hydrophilicity after aging
of the webs.
Examples 50-69 and Comparative Examples C27-C29
[0125] A ladder experiment was run to determine the effective use
levels of GML, SPAN.TM. 20 (SML) and PB 0400 polybutylene (PB) in
EOD 96-36 polypropylene. GML levels were varied from 0-2% and
SPAN.TM. 20 levels were varied from 0-2% so that the total of the
two levels was kept at 2%. Meanwhile, the level of PB was kept
constant at 7.5% in all cases except for Comparative Example C29,
which was run with polypropylene alone. Extrusion was done using
Melt-Blown Extrusion Procedure A, and the resulting webs were
evaluated for hydrophilicity using the Hydrophilicity Test (both
Cold Water and Hot Water) and the Percent Wet Pickup Test, both
described above. Web samples were evaluated initially and after
aging for 2000 hours at room temperature. Results from these
evaluations are presented in Table 8.
TABLE-US-00008 TABLE 8 Percent Wet Cold Hot Pickup: Water: Water:
Ex. % GML % SML % PB Initial Aged Init. Aged Init. Aged 50 2.0 --
7.5 745 .+-. 44 238 .+-. 23 1 4 1 1 51 1.9 0.1 7.5 809 .+-. 30 276
.+-. 70 1 4 1 1 52 1.8 0.2 7.5 773 .+-. 33 174 .+-. 34 1 4 1 1 53
1.7 0.3 7.5 749 .+-. 24 369 .+-. 41 1 3 1 1 54 1.6 0.4 7.5 751 .+-.
22 298 .+-. 47 1 3 1 1 55 1.5 0.5 7.5 749 .+-. 32 268 .+-. 23 1 3 1
1 56 1.4 0.6 7.5 753 .+-. 30 490 .+-. 48 1 2 1 1 57 1.3 0.7 7.5
1004 .+-. 17 666 .+-. 64 1 2 1 1 58 1.2 0.8 7.5 711 .+-. 14 627
.+-. 46 1 1 1 1 59 1.1 0.9 7.5 838 .+-. 104 709 .+-. 23 1 1 1 1 60
1.0 1.0 7.5 800 .+-. 28 615 .+-. 15 1 1 1 1 61 0.9 1.1 7.5 831 .+-.
25 563 .+-. 18 1 1 1 1 62 0.8 1.2 7.5 878 .+-. 40 644 .+-. 16 2 1 1
1 63 0.7 1.3 7.5 868 .+-. 37 641 .+-. 20 1 2 1 1 64 0.6 1.4 7.5 737
.+-. 112 665 .+-. 38 4 1.7 2 1 65 0.5 1.5 7.5 626 .+-. 55 655 .+-.
27 4 1 2 1 66 0.4 1.6 7.5 229 .+-. 36 605 .+-. 16 4 1.3 3 1 67 0.3
1.7 7.5 188 .+-. 43 706 .+-. 17 5 1.3 3 1 68 0.2 1.8 7.5 247 .+-.
68 568 .+-. 10 5 2.3 3 1.3 69 0.1 1.9 7.5 162 .+-. 31 659 .+-. 43 5
3 5 1.7 C27 -- 2.0 7.5 118 .+-. 37 381 .+-. 15 5 4.3 4 2 C28 -- --
7.5 6 .+-. 4 11 .+-. 8 5 5 5 5 C29 -- -- -- 9 .+-. 6 15 .+-. 20 5 5
5 5
[0126] Based on the results from both tests, the data in Table 8
show that substitution of GML with at least 15% SPAN.TM. 20 led to
improvement in cold water absorption after the web sample had aged.
Based on the Hydrophilicity Test results, overall optimum wetting
seemed to occur when about 40-60% of the GML was substituted with
SPAN.TM. 20. Interestingly, hydrophilicity often improved after
aging in web samples containing higher percentages of SPAN.TM.
20.
Examples 70 to 72
[0127] In Examples 70 to 72, compositions containing both GML and
HS-1 (glycerol monolaurates of high and low purity, respectively)
at various weight ratios were evaluated in polypropylene EOD 96-36
using Melt-Blown Extrusion Procedure A. The Hydrophilicity Test was
used to evaluate the wettability of each nonwoven web. A
description of the hydrocarbon surfactant compositions, their
monoglyceride content, calculated HLB values and wettability data
are presented in Table 9.
TABLE-US-00009 TABLE 9 Hydrocarbon Surfactants and Mono- Cold Hot
HLB Amounts glyceride Water Water Value Example (wt. %) (wt. %)
Rating Rating Surfactant 70 (1.5%) GML + 69.25 4.5 2 5.3 (1.5%)
HS-1 71 (2.25%) GML + 81.625 2.2 1 5.8 (0.75%) HS-1 72 (2.44%) GML
+ 84.71 2 1 5.93 (0.56%) HS-1
[0128] The data in Table 9 show that very good cold water
wettability can be achieved using the described combinations of
surfactants provided the overall HLB values of the surfactant
combinations were kept between about 5.8 and 5.93 (corresponds to a
monoglyceride content of at least 81.6 wt. % and 84.7 wt. %
respectively).
Examples 73 to 75 and Comparative Example C30
[0129] Four films were produced from the nonwoven webs of Examples
6 and 15, and Comparative Examples C5 and C15. The fabrics were
melted at 200.degree. C. in a platen press and then pressed with an
applied force of ten tons for about 45 seconds. The samples were
then allowed to air cool under the same pressure. The resulting
films were all seven mils (0.3 mm) thick.
[0130] A test was run to determine the anti-fog properties of the
four sample films. The test was performed as follows: Firstly, four
four-ounce glass jars were filled with warm water (approximately
30.degree. C.) to just below the neck. A silicone sealant (Cling 'n
Seal RTV silicone adhesive/sealant) was applied to the top of the
jar. Each film sample was placed on top of a jar to act as a lid,
and then the four jars were left for fifteen minutes at ambient
conditions to let the sealant set up. All of the film samples with
jars were then placed into an oil-bath that was heated to
50.degree. C. Data were then collected periodically as to amount of
water that had collected on the bottom of each film. Results are
shown in Table 10.
TABLE-US-00010 TABLE 10 Film Sample Condensation on Film at
Designated Time Example Components and Amounts (wt. %) 5 min. 30
min. 1 hr. 2 hrs. C30 (100%) Polypropylene Control Fogged over Fine
drops Small drops Small drops with vapor 73 (97%) Polypropylene +
(3%) HS-1 Very fine drops Small drops Large drops Large drops 74
(97%) Polypropylene + (3%) GML Small drops Large drops Large drops
Large drops 75 (93.5%) Polypropylene + (1.5%) GML + (5%) Large
drops Large drops Large drops Large drops Polybutylene PB 0400
[0131] The data in Table 10 show that one cannot distinguish the
anti-fog properties in films containing HS-1 at 3%, GML at 3%, and
GML at 1.5%+5% Shell PB0400 polybutylene. However, data on the cold
water wettability of webs prepared using the same extrudable
compositions (see Table 2) show that the wettability of webs
prepared from compositions containing 3% GML or 1.5% GML+5%
Polybutylene PB 0400 had a significantly better cold water wetting
rating (i.e., 1) than a web prepared from a composition containing
3% HS-1 (i.e., 5).
Example 76
[0132] This Example illustrates the preparation of an absorbent
device according to the invention. A melt-blown nonwoven web of
polypropylene was prepared from a polymer/monoester blend of Fina
3960X polypropylene and 3.0% by weight of GML using the Melt Blown
Extrusion Process B, described herein. The resulting web (basis
weight 130 g/m.sup.2) was combined with cellulose pulp (basis
weight 40 g/m.sup.2) commercially available from International Tray
Pads and Packaging, Inc. of Aberdeen, N.C. as 7 ply Hibulk Paper
Web using a process similar to that described in U.S. Pat. No.
4,100,324 (which disclosure is incorporated by reference herein) to
give a finished nonwoven absorbent web material.
[0133] A three-layer absorbent device was then prepared by
laminating together the above finished web material with a
liquid-impermeable polypropylene backing sheet prepared according
to the method described in U.S. Pat. No. 4,726,989 (Mrozinski),
(Example 1 without the solvent extraction of the oil) on one side
and a liquid-permeable non-stick netting (CKX215 P-S Netting,
commercially available from Applied Extrusion Technologies,
Middletown, Del.) on the other side. The lamination was carried out
using hexagonal honeycomb patterned rolls heated to 132.degree. C.
and gapped at 0.12 to 0.25 mm. The dressing was observed to
immediately absorb body-temperature water on the side with the
non-stick netting.
Examples 77 to 81
[0134] These Examples illustrate the antimicrobial activity of
nonwoven webs used to prepare the absorbent devices.
[0135] Melt-blown nonwoven webs were prepared using PP3505
polypropylene and various amounts of GML using a process similar to
the Melt-Blown Extrusion Process B except with a flow rate of 0.45
Kg/hr and a temperature range of 250.degree. C. to 280.degree. C.
In the case of Example 77, the resulting web was further combined
with cellulose pulp using a process and a material similar to that
described in Example 76. In Example 81, following extrusion of the
hot polymeric fibers, an aqueous solution of LA was sprayed onto
the fibers to achieve a level of 1.5% (based on the total weight of
the coated and dried web). The heat of the polymer evaporated the
water and left the lactic acid intimately in contact with the
GML-containing fibers.
[0136] The resulting webs were then evaluated for antimicrobial
activity using the Antimicrobial Test and Staphylococcus aureus.
The concentrations of GML used to prepare the Examples, the web
basis weights and the web antimicrobial activities are summarized
in Table 11. The antibacterial data in Table 11 are percent
reductions in bacterial colony forming units (CFU) after a 24-hour
exposure time at 23-24.degree. C. These data show that all test
samples possessed bactericidal activity although the material
treated with lactic acid after extrusion showed the greatest
percent kill of S. aureus.
TABLE-US-00011 TABLE 11 GML Lactic Acid Reduction of Bacterial Web
Basis Example (%) (%) CFU (%) Wt. (g/m.sup.2) 77 2.0 0 98.63 103 78
2.0 0 99.91 68 79 1.0 0 96.83 52 80 1.5 0 94.48 52 81 2.0 1.5 99.99
65
Examples 82-86
[0137] These Examples illustrate the degree of water absorbency of
various nonwoven web constructions of this invention.
[0138] In Examples 82-84, melt-blown polypropylene nonwoven webs
were prepared using PP3505 polypropylene and various amounts of GML
using a process similar to the Melt-Blown Extrusion Process B,
except that the monoester throughput rate was about 6.8 kg/hr and
the die width was about 51 cm.
[0139] In Example 85, a melt-blown polypropylene nonwoven web was
prepared using PP3746 polypropylene, 7.5% PB 0400 polybutylene, and
2.0% GML using a process similar to the Melt-Blown Extrusion
Process B, except that the monoester throughput rate was about 9.1
kg/hr and the die width was about 51 cm.
[0140] In Example 86, a sample of the three-layer absorbent device
prepared as generally described in Example 76 was employed. The
nonwoven polypropylene web component was made using 3.0% GML and
had a resulting basis weight of 130 g/m.sup.2. The average dry
weights of the individual components of a 7.62 cm.times.7.62 cm
sample of the device were 0.16 g (netting), 0.13 g (film backing),
and 0.96 g (absorbent polypropylene/cellulose pulp core).
[0141] The amount of water absorbed, and the percent water
absorbency of 7.62 cm x 7.62 cm samples of Examples 82-86 were
measured according to the Percent Water Absorbency Test described
above. Results are provided in Table 12.
TABLE-US-00012 TABLE 12 GML Water Absorbed Percent Water Example
(%) (g) Absorbency (%) 82 3.0 10.29 1278 83 4.0 9.62 1177 84 5.0
10.14 1254 85 2.0 9.90 1127 86 3.0 11.47 919* *Percent Water
Absorbency = 1211% based on dry weight of the device less the dry
weight of netting and film components.
[0142] The data in Table 12 show that all samples were highly water
absorbent with each sample capable of absorbing over ten times its
own weight with water. For these Examples, there was not a
significant correlation between % water absorbency and levels of
GML present in the samples.
Examples 87-89 and Comparative Example C31
[0143] These examples illustrate the hydrophilicity of various
spunbond fabrics of this invention.
[0144] Using the Spunbond Extrusion Procedure with minor
modifications, spunbond fabrics containing various percentages of
GML, PB 0400 polybutylene and/or SPAN.TM. 20 in EXXON.TM. 3155
polypropylene were prepared.
[0145] In Example 87, the extruded polymer mixture consisted of
93.5% 3155, 1.5% GML and 5% PB 0400.
[0146] In Example 88, the extruded polymer mixture consisted of
88.5% 3155, 1.05% GML, 0.45% SPAN.TM. 20 and 10% PB 0400.
[0147] In Example 89, the extruded polymer mixture consisted of
86.2% 3155, 1.65% GML, 0.85% SPAN.TM. 20 and 11.33% PB 0400.
[0148] In Comparative Example C31, the extruded polymer mixture
consisted of 95% 3155 and 5% PB 0400 (no hydrophilic additive).
[0149] The fabrics were tested for hydrophilicity using the Drop
Wetting Test. Results from these tests are shown below in Table
13.
TABLE-US-00013 TABLE 13 Processing Conditions: Ex. 87 Ex. 88 Ex. 89
C. Ex. C31 Melt Temp. (.degree. C.) 199 207 227 196 Throughput
(g/hole/min) 0.15 0.15 0.25 0.15 Basis Weight (g/m.sup.2) 20 20 17
20 No. of Drops/10 Absorbed 3 5 4 0
[0150] The data in Table 13 show that all of the spunbond samples
containing GML (Examples 87-89) demonstrated hydrophilicity, while
the sample without the GML (Comparative Example C31) was
hydrophobic.
Examples 90-109 and Comparative Example C32
[0151] These examples illustrate the use of various polymer
additives at the 10% level to improve the hydrophilicity of
melt-blown web samples made of EOD 96-36 polypropylene containing
GML and 70/30 blends of GML/SPAN.TM.. Extrusion was done using
Melt-Blown Extrusion Procedure A, and the resulting web samples
were evaluated for initial hydrophilicity to hot and cold water
using the Hydrophilicity Test. Results from these evaluations are
presented in Table 14.
TABLE-US-00014 TABLE 14 Polymer Cold Hot Ex. % GML % SPAN .TM. 20
Additive Water Water C32 -- -- -- 5 5 90 1 -- -- 4.3 5 91 1.25 --
-- 4.3 3.6 92 1.5 -- -- 2 3 93 2 -- -- 1.3 1.7 94 2 -- PB 0400 1 1
95 1.25 -- PB 0400 1 1 96 1.25 -- DP-8340 1 1 97 1.25 -- 8401 1 1
98 1.25 -- 8402 1 1 99 1.25 -- 4023 1 1 100 1.25 -- 8910 1 1 101
1.4 0.6 -- 2 2.3 102 1.23 0.52 -- 2.3 3 103 1.05 0.45 -- 2.3 3 104
1.05 0.45 PB 0400 1 1 105 1.05 0.45 DP-8340 1 1.2 106 1.05 0.45
DP-8910 1 1 107 1.05 0.45 4023 1 1 108 1.05 0.45 8401 1 1 109 1.05
0.45 8402 1 1
The data in Table 14 shows that the polyolefinic hydrophilic
enhancers all improved the hydrophilicity of the nonwoven web
samples.
[0152] The complete disclosures of the patents, patent documents,
and publications cited herein are hereby incorporated by reference
in their entirety as if each were individually incorporated.
Various modifications and alterations to this invention will become
apparent to those skilled in the art without departing from the
scope and spirit of this invention. It should be understood that
this invention is not intended to be unduly limited by the
illustrative embodiments and examples set forth herein and that
such examples and embodiments are presented by way of example only
with the scope of the invention intended to be limited solely by
the claims set forth herein as follows.
* * * * *