U.S. patent application number 17/637784 was filed with the patent office on 2022-09-08 for wound dressing material and methods of making and using the same.
The applicant listed for this patent is 3M INNOVATIVE PROPERTIES COMPANY. Invention is credited to Saurabh Batra, Rajan B. Bodkhe, Semra Colak Atan, Colby W. Dotseth, Joseph A. Dunbar, Naimul Karim, Petra L. Kohler Riedi, Joseph J. Stoffel.
Application Number | 20220280681 17/637784 |
Document ID | / |
Family ID | 1000006420154 |
Filed Date | 2022-09-08 |
United States Patent
Application |
20220280681 |
Kind Code |
A1 |
Kohler Riedi; Petra L. ; et
al. |
September 8, 2022 |
WOUND DRESSING MATERIAL AND METHODS OF MAKING AND USING THE
SAME
Abstract
A wound dressing material comprises a base fiber web, a
wound-contact scrim, and an antimicrobial layer. The wound-contact
scrim comprises water-sensitive fibers comprising a copolymer
comprising divalent hydroxyethylene monomer units and divalent
dihydroxybutylene monomer units. The antimicrobial layer is
sandwiched between the base fiber web and the wound-contact scrim.
The wounds dressing material may be contacted with an exposed
surface of a wound. A method of making the wound dressing material
is also disclosed.
Inventors: |
Kohler Riedi; Petra L.;
(Minneapolis, MN) ; Batra; Saurabh; (Minneapolis,
MN) ; Karim; Naimul; (Maplewood, MN) ;
Stoffel; Joseph J.; (Hastings, MN) ; Bodkhe; Rajan
B.; (Woodbury, MN) ; Dunbar; Joseph A.;
(Woodbury, MN) ; Dotseth; Colby W.; (Baldwin,
WI) ; Colak Atan; Semra; (St. Louis Park,
MN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
3M INNOVATIVE PROPERTIES COMPANY |
St. Paul |
MN |
US |
|
|
Family ID: |
1000006420154 |
Appl. No.: |
17/637784 |
Filed: |
September 24, 2020 |
PCT Filed: |
September 24, 2020 |
PCT NO: |
PCT/IB2020/058942 |
371 Date: |
February 23, 2022 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62905647 |
Sep 25, 2019 |
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61L 2300/404 20130101;
A61L 15/44 20130101; A61L 15/225 20130101; A61L 15/22 20130101;
C08L 67/02 20130101; A61L 15/225 20130101; C08L 29/04 20130101;
A61L 15/225 20130101; C08L 75/08 20130101 |
International
Class: |
A61L 15/44 20060101
A61L015/44; A61L 15/22 20060101 A61L015/22 |
Claims
1. A wound dressing material comprising: a base fiber web having
first and second opposed major sides; a first wound-contact scrim
comprising first water-sensitive fibers, wherein the first
water-sensitive fibers comprise a first copolymer comprising
divalent hydroxyethylene monomer units and divalent
dihydroxybutylene monomer units; and a first antimicrobial layer
sandwiched between the first major side of the base fiber web and
the first wound-contact scrim.
2. The wound dressing material of claim 1, further comprising a
flexible adhesive barrier film adhered to and proximate to the
second major side of the base fiber web.
3. The wound dressing material of claim 1, further comprising: a
second wound-contact scrim comprising second water-sensitive
fibers, wherein the second water-sensitive fibers comprise a second
copolymer comprising divalent hydroxyethylene monomer units and
divalent dihydroxybutylene monomer units; and a second
antimicrobial layer sandwiched between the second major side of the
base fiber web and the second wound-contact scrim.
4. The wound dressing material of claim 1, wherein the first
water-sensitive fibers are multilayered and further comprise a
polyurethane layer sandwiched between two layers of copolymer
comprising divalent hydroxyethylene monomer units and divalent
dihydroxybutylene monomer units.
5. The wound dressing material of claim 1, wherein the first
water-sensitive fibers have an average fiber diameter of 2 to 100
microns.
6. The wound dressing material of claim 1, wherein the first
wound-contact scrim further comprises secondary fibers comprising
at least one of polyvinyl alcohol, carboxymethyl cellulose, rayon,
cotton, cellulose acetate, thermoplastic polyurethane, chitosan,
polyacrylic acid, sulfonated cellulose, alginate, or cellulose
ethyl sulfonate.
7. The wound dressing material of claim 1, wherein the first
wound-contact scrim further comprises secondary fibers comprising
at least one of polyethylene, polypropylene, polybutylene,
poly(ether ether ketone), poly-4-methylpentene, polyethylene
terephthalate, polyvinyl chloride, polymethyl methacrylate,
polyacrylonitrile, a polyamide, a polyester, polystyrene, a
styrenic block copolymer, a polyurethane comprising polyethers, a
block copolymers of polyether, or polypropylene oxide.
8. The wound dressing material of claim 1, wherein the base fiber
web comprises base fibers comprising at least one of polyolefin,
polyester, polyvinyl chloride, polymethyl methacrylate,
polyacrylonitrile, polyamide, polystyrene, or polyurethane.
9. The wound dressing material of claim 1, wherein the base fiber
web comprises base fibers comprising at least one of polyvinyl
alcohol, carboxymethyl cellulose, rayon, cotton, cellulose acetate,
thermoplastic polyurethane, chitosan, polyacrylic acid, sulfonated
cellulose, alginate, or cellulose ethyl sulfonate.
10. The wound dressing material of claim 1, wherein the first
copolymer further comprises divalent acetoxyethylene monomer
units.
11. The wound dressing material of claim 1, wherein the divalent
dihydroxybutylene monomer units comprise divalent
3,4-dihydroxybutan-1,2-diyl monomer units.
12. The wound dressing material of claim 1, wherein the base fiber
web comprises at least one of polyolefin fibers, polyester fibers,
polyamide fibers, styrenic block copolymer fibers, polyurethane
fibers, metal fibers, ceramic fibers, or natural fibers.
13. The wound dressing material of claim 1, wherein the first
wound-contact scrim is melt-blown or spunbonded.
14. A method of using a wound dressing material, the method
comprising contacting the first wound-contact scrim of the wound
dressing material of claim 1 with an exposed surface of a
wound.
15. A method of using a wound dressing material, the method
comprising contacting the first wound-contact scrim of the wound
dressing material of claim 2 with an exposed surface of a
wound.
16. A method of making a wound dressing material, the method
comprising laminating sequential layers: a) a first wound-contact
scrim comprising water-sensitive fibers, wherein the
water-sensitive fibers comprise a first copolymer comprising
divalent hydroxyethylene monomer units and divalent
dihydroxybutylene monomer units; b) a first antimicrobial layer;
and c) a base fiber web.
17. The method of claim 16, wherein the sequential layers further
comprise: d) a second antimicrobial layer; and e) a second
wound-contact scrim comprising second water-sensitive fibers,
wherein the second water-sensitive fibers comprise a second
copolymer comprising divalent hydroxyethylene monomer units and
divalent dihydroxybutylene monomer units.
18. The method of claim 16, wherein the sequential layers further
comprise d) a flexible adhesive barrier film adhered to and
proximate to the second major side of the base fiber web.
19. The method of claim 16, wherein the sequential layers are
laminated simultaneously.
Description
TECHNICAL FIELD
[0001] The present disclosure broadly relates to antimicrobial
wound dressing materials, to processes suitable for the preparation
of such materials, and to the use of such materials as wound
dressings.
BACKGROUND
[0002] Traditionally, wet-to-dry gauze has been used to dress
wounds. Dressings that create and maintain a moist environment,
however, are now typically considered to provide optimal conditions
for wound healing. Indeed, highly hydrophilic and absorbent wound
dressing materials are part of the rapidly growing advanced wound
care market. High-gelling fiber wound dressing products are popular
with clinicians and are made of materials which absorb and hold
moisture to create a gel-like environment to maintain moisture at
the wound site. The most common materials used in these products
are alginate and carboxymethyl cellulose.
[0003] Many wound care products include cationic antiseptics, which
kill a wide variety of microorganisms, but are sequestered and/or
deactivated by anionic materials such as alginate and carboxymethyl
cellulose in the wound care product itself. Rayon is another highly
hydrophilic material often used in wound care products, but it
likewise also binds cationic antimicrobial molecules.
[0004] There is a continuing need for materials and articles to
facilitate wound healing.
SUMMARY
[0005] Advantageously, the present disclosure provides antiseptic
wound dressing materials that provide a moist environment while
providing antimicrobial protection, even in the presence of
cationic antiseptics.
[0006] In one aspect, the present disclosure provides a wound
dressing material comprising:
[0007] a base fiber web having first and second opposed major
sides;
[0008] a first wound-contact scrim comprising first water-sensitive
fibers, wherein the first water-sensitive fibers comprise a first
copolymer comprising divalent hydroxyethylene monomer units and
divalent dihydroxybutylene monomer units; and
[0009] a first antimicrobial layer sandwiched between the first
major side of the base fiber web and the first wound-contact
scrim.
[0010] In another aspect, the present disclosure provides a method
of using a wound dressing material, the method comprising
contacting the first wound-contact scrim of a wound dressing
material according to the present disclosure with an exposed
surface of a wound.
[0011] In yet another aspect, the present disclosure provides a
method of making a wound dressing material, the method comprising
laminating sequential layers:
[0012] a) a first wound-contact scrim comprising water-sensitive
fibers, wherein the water-sensitive fibers comprise a first
copolymer comprising divalent hydroxyethylene monomer units and
divalent dihydroxybutylene monomer units;
[0013] b) a first antimicrobial layer; and
[0014] c) a base fiber web.
[0015] As used herein:
[0016] the term "scrim" refers to a lightweight highly porous
fabric that may be woven or nonwoven;
[0017] the term "water-sensitive" means water swellable and/or
water-soluble; and
[0018] the term "wound" refers to an injury to a subject (e.g., a
mammal) which involves a break in the normal skin barrier exposing
tissue below, which is caused by, for example, lacerations,
surgery, burns, damage to underlying tissue such as pressure sores,
or poor circulation. Wounds are understood to include both acute
and chronic wounds.
[0019] Features and advantages of the present disclosure will be
further understood upon consideration of the detailed description
as well as the appended claims
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] FIG. 1 is a schematic side view of an exemplary wound
dressing material 100 according to the present disclosure.
[0021] FIG. 2 is a schematic side view of another exemplary wound
dressing material 200 according to the present disclosure.
[0022] Repeated use of reference characters in the specification
and drawings is intended to represent the same or analogous
features or elements of the disclosure. It should be understood
that numerous other modifications and embodiments can be devised by
those skilled in the art, which fall within the scope and spirit of
the principles of the disclosure. The figures may not be drawn to
scale.
DETAILED DESCRIPTION
[0023] Referring now to FIG. 1, wound dressing material 100
comprises base fiber web 110 having first and second opposed major
sides (112, 114). First wound-contact scrim 120a comprises
water-sensitive fibers comprising a first copolymer divalent
hydroxyethylene monomer units and divalent dihydroxybutylene
monomer units. First antimicrobial layer 130a is sandwiched between
first major side 112 of base fiber web 110 and first wound-contact
scrim 120a. Optional second wound-contact scrim 120b comprises
second water-soluble fibers comprising a second copolymer
comprising divalent hydroxyethylene monomer units and divalent
dihydroxybutylene monomer units. Optional second antimicrobial
layer 130b is sandwiched between second major side 114 of base
fiber web 110 and optional second wound-contact scrim 120b.
[0024] The base fiber web comprises base fibers. The base fibers
may be staple, and/or continuous. For example, the base fiber web
may comprise an entangled staple fiber web, a meltblown fiber web,
or a spunbond fiber web. Staple fibers may be entangled by
needletacking and/or hydroentanglement, for example. The base fiber
web fibers may have any average diameter and/or length, preferably
from 2 to 200 microns and more preferably 2 to 100 microns.
[0025] While the base fiber web may have any basis weight, in many
embodiments, it is preferably in the range of 20 to 500 grams per
square meter (gsm), more preferably 50 to 400 gsm, and more
preferably 75 to 300 gsm.
[0026] In some embodiments, for example, where resistance to
exudate and/or water swellability/solubility is desired, the base
fibers may comprise polyolefin(s) (e.g., polyethylene (HDPE, LDPE,
LLDPE, VLDPE; ULDPE, UHMW-PE), polypropylene, polybutylene,
poly(1-butene), polyisobutylene, poly(1-pentene),
poly(4-methylpent-1-ene), polybutadiene, or polyisoprene),
polyester(s) (e.g., polylactic acid, polybutylene terephthalate,
and polyethylene terephthalate), polyvinyl chloride, polymethyl
methacrylate, polyacrylonitrile and copolymer(s) of acrylonitrile,
polyamide(s) (e.g., polycaprolactam or nylon 6,6), polystyrene(s),
polyphenylene sulfide(s), polysulfone(s), polyoxymethylene(s),
polyimide(s), polyurea(s), hydrophobic thermoplastic
polyurethane(s), styrenic block copolymer(s) (e.g.,
styrene-isoprene-styrene (SIS) block copolymers,
styrene-ethylene-butadiene-styrene (SEBS) block copolymers, or
styrene-butadiene-styrene (SBS) block copolymers), metal (e.g.,
stainless steel, nickel, tin, silver, copper, or aluminum fibers),
glass fibers, ceramic fibers, natural fiber(s) (e.g., cotton
fibers, wool fibers, cashmere fibers, kenaf fibers, jute fibers,
flax fibers, hemp fibers, cellulosic fibers, sisal fibers, coir
fibers), or any combination thereof.
[0027] In some embodiments, for example, where solubility and/or
swellability in exudate and/or water is desired, the base fibers
may comprise polyvinyl alcohol(s), carboxymethyl cellulose, rayon,
cotton, cellulose acetate, hydrophilic thermoplastic
polyurethane(s), chitosan, polyacrylic acid, sulfonated cellulose,
cellulose ethyl sulfonate, alginate, or any combination
thereof.
[0028] Blends of fibers with and without resistance to exudate
and/or water swellability/solubility can also be used for the base
fiber web and/or the first and/or optional second wound-contact
scrims.
[0029] The first and optional second wound-contact scrims may be
the same or different. They comprise water-sensitive fibers that
comprise first and optionally second copolymers (which may be the
same or different), each respective copolymer comprising divalent
hydroxyethylene monomeric units (i.e.,
##STR00001##
and divalent dihydroxybutylene monomer units. In preferred
embodiments, the divalent dihydroxybutvlene monomer units comprise
3,4-dihydroxybutan-1,2-diyl monomer units (i.e.,
##STR00002##
Optionally, but typically, the copolymer furthers comprise
acetoxyethylene divalent monomeric units (i.e., (i.e.,
##STR00003##
The copolymer may be obtained by copolymerization of vinyl acetate
and 3,4-dihydroxy-1-butene followed by partial or complete
saponification of the acetoxy groups to form hydroxyl groups.
[0030] Alternatively, in place of 3,4-dihydroxy-1-butene, a
carbonate such as
##STR00004##
can also be used. After copolymerization, this carbonate may be
hydrolyzed simultaneously with saponification of the acetate
groups. In another embodiment, in place of 3,4-dihydroxy-1-butene,
an acetal or ketal having the formula:
##STR00005##
where each R is independently hydrogen or alkyl (e.g., methyl or
ethyl). After copolymerization, this carbonate may be hydrolyzed
simultaneously with saponification of the acetate groups, or
separately. The copolymer can be made according to known methods or
obtained from a commercial supplier, for example.
[0031] Commercially available copolymers may include those
available under the trade designation Nichigo G-Polymer (Nippon
Gohsei Synthetic Chemical Industry, Osaka, Japan), a highly
amorphous polyvinyl alcohol, that is believed to have divalent
monomer units of hydroxyethylene, 3,4-dihydroxybutan-1,2-diyl, and
optionally acetoxyethylene. Nippon Gohsei also refers to Nichigo
G-Polymer by the chemical name butenediol vinyl alcohol (BVOH).
Exemplary materials include Nichigo G-Polymer grades AZF8035W,
OKS-1024, OKS-8041, OKS-8089, OKS-8118, OKS-6026, OKS-1011,
OKS-8049, OKS-1028, OKS-1027, OKS-1109, OKS-1081, and OKS-1083.
These copolymers are believed to have a saponification degree of 80
to 97.9 mole percent, and further contain an alkylene oxide adduct
of a polyvalent alcohol containing 5 to 9 moles of an alkylene
oxide per mole of the polyvalent alcohol. These materials have
melt-processing properties that are suitable for forming melt-blown
and spunbond webs.
[0032] In some embodiments, the first and/or second water soluble
fibers comprises three-layered fibers that an inner polymer layer
(e.g., a polyurethane layer) sandwiched between two layers of the
copolymer(s) described hereinbefore.
[0033] The first and optional second wound-contact scrims may
contain secondary fibers in addition to the copolymer fibers.
Suitable secondary fiber may include all fibers listed for the base
fiber web hereinbefore. Preferred secondary fibers include fibers
comprising polyvinyl alcohol(s), carboxymethyl cellulose, rayon,
cotton, cellulose acetate, hydrophilic thermoplastic
polyurethane(s), chitosan, polyacrylic acid, sulfonated cellulose,
cellulose ethyl sulfonate, alginate, or any combination
thereof.
[0034] Methods of forming the base fiber web and the wound-contact
scrim(s) will depend on the type of fiber web formed, but will be
well-known to those of skill in the textile arts. Suitable methods
may include airlaying and/or carding of staple fibers followed by
needletacking to densify and strengthen the fiber web; melt-blown;
spunbond; and wet-laid processes. The base fiber web may be
heat-calendered to densify and/or improve the base fiber web
handling properties.
[0035] In some embodiments, nonwoven fiber webs (e.g., the base
fiber web and/or the wound-contact scrim(s) may be made by
air-laying of staple fibers. Air-laid nonwoven fiber webs may be
prepared using equipment such as, for example, that available as a
RANDO WEBBER from Rando Machine Company of Macedon, N.Y. In some
embodiments, a type of air-laying may be used that is termed
gravity-laying, as described e.g., in U. S. Pat. Application
Publication 2011/0247839 (Lalouch). Nonwoven staple fiber webs may
be densified and strengthened, for example, by techniques such as
crosslapping, stitchbonding, needletacking, chemical bonding,
and/or thermal bonding.
[0036] Melt-blowing methods are well-known in the art. As used
herein, the term "melt-blowing" refers to a process in which fibers
are formed by extruding a molten thermoplastic material through a
plurality of fine, usually circular, die capillaries into a high
velocity gas (e.g., air) stream which attenuates the molten
thermoplastic material and forms fibers, which can be to microfiber
diameter, such as less than 10 microns in diameter. Thereafter, the
melt-blown fibers are carried by the gas stream and are deposited
on a collecting surface to form a web of random melt-blown fibers.
Such a process is disclosed, for example, in U.S. Pat. No.
3,849,241 (Butin et al.); U.S. Pat. No. 4,307,143 (Meitner et al.);
and U.S. Pat. No. 4,707,398 (Wisneski et al.).
[0037] Fibers in the wound-contact scrims may be staple and/or
continuous, preferably at least substantially continuous. For
example, the first and/or optional second wound-contact scrims may
comprise a meltblown fiber web or a spunbond fiber web. Fibers in
the wound-contact scrims may have any average diameter and/or
length, preferably from 2 to 200 microns and more preferably 2 to
100 microns.
[0038] The wound-contact scrim may have any basis weight, but in
many embodiments, it is preferably in the range of 5 to 150 gsm,
more preferably 10 to 100 gsm, and more preferably 10 to 75
gsm.
[0039] Optionally, wound-contact scrims may further comprise at
least one of addition of a plurality of staple fibers or addition
of particulates. Suitable methods are described in U.S. Pat. No.
4,118,531 (Hauser), U.S. Pat. No. 6,872,3115 (Koslow), and U.S.
Pat. No. 6,494,974 (Riddell); and in U.S. Pat. Appl. Publ. Nos.
2005/0266760 (Chhabra et al.), 2005/0287891 (Park), and
2006/0096911 (Brey et al.). In other exemplary embodiments, the
optional particulates may be added to a nonwoven fiber stream by
air laying a fiber web, adding particulates to the fiber web (e.g.,
by passing the web through a fluidized bed of particulates),
optionally with post heating of the particulate-loaded web to bond
the particulates to the fibers.
[0040] The antimicrobial layers provide effective topical
antimicrobial activity and thereby treat and/or prevent a wide
variety of afflictions. For example, they can be used in the
treatment and/or prevention of afflictions that are caused, or
aggravated by, microorganisms (e.g., Gram positive bacteria, Gram
negative bacteria, fungi, protozoa, mycoplasma, yeast, viruses, and
even lipid-enveloped viruses) on skin. Particularly relevant
organisms that cause or aggravate such afflictions include
Staphylococcus spp., Streptococcus spp., Pseudomonas spp.,
Enterococcus spp., and Esherichia spp., bacteria, as well as herpes
virus, Aspergillus spp., Fusarium spp., Candida spp., as well as
combinations thereof. Particularly virulent organisms include
Staphylococcus aureus (including resistant strains such as
Methicillin Resistant Staphylococcus aureus (MRSA), Staphylococcus
epidermidis, Sfreptococcus pneumoniae, Enterococcus faecalis,
Vancomycin Resistant Enterococcus (VRE), Pseudomonas aeruginosa,
Escherichia coli, Aspergillus niger, Aspergillus fumigatus,
Aspergillus clavatus, Fusarium solani, Fusarium oxysporum, Fusarium
chlamydosporum, Candida albicans, Candida glabrata, Candida krusei,
and combinations thereof.
[0041] In some embodiments, the antimicrobial layers may be a
surface coating (e.g., a paste or gel) on either or both of the
base fiber web or a wound-contact scrim or it may be a freestanding
layer (e.g., a film).
[0042] In some embodiments, antimicrobial layers, when provided as
a free thin film (i.e., not as a coating on a substrate) have a
basis weight in the range of 20 to 700 gsm, more preferably in the
range of 75 to 600 gsm, and more preferably in the range of 100 to
500 gsm, are typically flexible and can be deformed without
breaking, shattering, or flaking of the antimicrobial layer.
[0043] Each antimicrobial layer comprises at least one
antimicrobial compound. Exemplary antimicrobial compounds include
antibiotics (e.g., amoxicillin, bacitracin zinc, doxycycline,
cephalexin, ciprofloxacin, clindamycin, metronidazole,
azithromycin, sulfamethoxazole, trimethoprim, or levofloxacin), and
antiseptics such as chlorhexidine and its salts (e.g.,
chlorhexidine digluconate and chlorhexidine diacetate),
antimicrobial lipids, phenolic antiseptics, cationic antiseptics,
iodine and/or an iodophor, peroxide antiseptics, antimicrobial
natural oils, alkane-1,2-diols having 6 to 12 carbon atoms, silver,
silver salts and complexes, silver oxide, copper, copper salts, and
combinations thereof. Preferred antimicrobial compounds include
antimicrobial quaternary amine compounds (e.g., benzalkonium
chloride) and salts thereof, cationic surfactants (e.g.,
cetylpyridinium chloride or cetyltrimethylammonium bromide),
polycationic compounds such as octenidine or a salt thereof,
biguanide compounds (e.g., chlorhexidine,
polyhexamethylenebiguanide (PHMB) or a salt thereof, 1,2-organic
diols having 6 to 12 carbon atoms (e.g., 1,2-octanediol),
antimicrobial fatty acid monoester compounds, and combinations
thereof.
[0044] Wound dressing materials according to the present disclosure
may have broad-spectrum antimicrobial activity. However, the wound
dressing materials are typically sterilized; for example, by
sterilized by a variety of industry standard techniques. For
example, it may be preferred to sterilize the wound dressing
materials in their final packaged form using electron beam. It may
also be possible to sterilize the sample by gamma radiation,
nitrogen dioxide sterilization and/or heat. Other forms of
sterilization may also be used. It may also be suitable to include
preservatives in the formulation to prevent growth of certain
organisms Suitable preservatives include industry standard
compounds such as parabens (e.g., methylparaben, ethylparaben,
propylparaben, isopropylparaben, or isobutylparaben); 2 bromo-2
nitro-1,3-diol; 5 bromo-5-nitro-1,3-dioxane, chlorbutanol,
diazolidinyl urea; iodopropyl butyl carbamate, phenoxyethanol,
halogenated cresols, methylchloroisothiazolinone; and combinations
thereof.
[0045] Many preferred antimicrobial layers comprise an effective
amount of a polycarboxylic acid chelator compound, alone or in
combination with any of the foregoing antimicrobial compounds. The
amount is effective to prevent growth of a microorganism and/or to
kill microorganisms on a surface to which the composition is
contacted.
[0046] In certain embodiments, the polycarboxylic acid chelator
compound, whether aliphatic, aromatic, or a combination thereof,
comprises at least two carboxylic acid groups. In certain
embodiments, the polycarboxylic acid chelator compound, whether
aliphatic, aromatic or a combination thereof, comprises at least
three carboxylic acid groups. In certain embodiments, the
polycarboxylic acid chelator compound, whether aliphatic or
aromatic, comprises at least four carboxylic acid groups.
[0047] Polycarboxylic acid-containing chelator compounds suitable
for use in antimicrobial layer include aliphatic polycarboxylic
acids, aromatic polycarboxylic acids, compounds with both one or
more aliphatic carboxylic acids and one or more aromatic carboxylic
acids, salts thereof, and combinations of the foregoing.
Nonlimiting examples of suitable polycarboxylic acid-containing
chelator compounds include citric acid, glutaric acid, glutamic
acid, maleic acid, succinic acid, tartaric acid, malic acid,
ethylenediaminetetraacetic acid, phthalic acid, trimesic acid, and
pyromellitic acid.
[0048] Preferred salts include those formed from monovalent
inorganic bases and include cations such as K.sup.+, Na.sup.+,
Li.sup.+, and Ag.sup.+, and combinations thereof. In some
compositions polyvalent bases may be appropriate and include
cations such as Ca.sup.2+, Mg.sup.2+, Zn.sup.2+, Alternatively, the
salt of the polycarboxylic acid may be formed using an organic base
such as a primary, secondary, tertiary, or quaternary amine.
[0049] In many embodiments, the polycarboxylic acid-comprising
chelator compound may be present in the antimicrobial layer at
relatively high concentrations (on a weight basis) while the
composition remains surprisingly nonfrangible. The minimum
effective amount of chelator compound in the antimicrobial layer is
related to the number of carboxyl groups in the chelator compound.
For example, succinic acid (with two carboxyl groups) is generally
more efficacious than glutamic acid having the same number of
carboxylic acid groups since in glutamic acid carboxyl group forms
a zwitterion with an amino group.
[0050] Mucic acid is another example with 2 carboxyl groups. Mucic
acid is not as efficacious as succinic acid since the carboxyl
groups are further apart and sterically hindered. In certain
embodiments, efficacy of the composition can be improved by using
thicker (greater basis weight) antimicrobial layers. Efficacy may
depend on the amount of acid in the antimicrobial layer as well as
the total amount (mass) of the antimicrobial layer. Thus, in some
embodiments, the chelator compound comprises at least about 5, 10,
15, 20, 25, 30, 35, 40, 45, 50, 55, or even at least 60 percent by
weight of an essentially solvent-free antimicrobial layer. The term
"essentially solvent-free" is understood to mean that the
antimicrobial layer has been processed to remove most of the
solvent (e.g., water and/or organic solvent) or has been processed
in such a way that no solvent (e.g., water and/or organic solvent)
was required. This is generally the article for sale, e.g., before
it has been applied to a patient. Generally, solvents are
relatively volatile compounds having a boiling point at one
atmosphere pressure of less than 150.degree. C. Solvent may be used
to process (e.g., coat or film-form) the antimicrobial layer, but
is preferably substantially removed to produce the final article
for sale. For example, certain precursor compositions used to form
the antimicrobial layer are first combined with water as a vehicle
to form a solution, emulsion, or dispersion. These precursor
compositions are coated and dried on a substrate (e.g., a release
liner, the base fiber web, and/or the wound-contact scrim(s)) such
that the water content of the antimicrobial layer is less than 10
percent by weight, preferably less than 5 percent by weight, and
more preferably less than 2 percent by weight.
[0051] In some embodiments, the chelator compound comprises up to
about 15, 20, 25, 30, 35, 40, 45, 50, 55, or even up to about 60
percent by weight of the essentially dry antimicrobial layer on a
weight basis.
[0052] In certain embodiments, wherein the polycarboxylic
acid-comprising chelator compound comprises two aliphatic
carboxylic acid groups (e.g., succinic acid), the chelator compound
comprises at least about 10 percent by weight of the essentially
dry antimicrobial layer on a weight basis. In certain embodiments,
wherein the polycarboxylic acid-comprising chelator compound
comprises three aliphatic carboxylic acid groups (e.g., citric
acid), the chelator compound comprises at least about 10 percent by
weight of the essentially dry antimicrobial layer on a weight
basis. In certain embodiments, wherein the polycarboxylic
acid-comprising chelator compound comprises four aliphatic
carboxylic acid groups (e.g., ethylenediaminetetraacetic acid), the
chelator compound comprises at least about 5 percent by weight of
the essentially dry antimicrobial layer on a weight basis.
[0053] When preparing antimicrobial layers of the present
disclosure, the polycarboxylic acid-containing chelator compound
may be dissolved and/or dispersed in a water-soluble plasticizer
component and optionally a solvent such as water. The plasticizer
component has a boiling point greater than 105.degree. C. and has a
molecular weight of less than 5000 daltons. Preferably, the
plasticizer component is a liquid at 23.degree. C. Typically, but
not necessarily, the plasticizer component is the most abundant
solvent in the antimicrobial layer in which the polycarboxylic
acid-containing chelator compound is dissolved and/or dispersed. In
certain embodiments wherein water is used to prepare the
antimicrobial layer, substantially all of the water is subsequently
removed (e.g., after the antimicrobial layer has been coated onto a
substrate).
[0054] In certain embodiments, the chelator compound comprises an
aliphatic and/or aromatic polycarboxylic acid, in which two or more
of the carboxylic groups are available for chelation without any
zwitterionic interaction. Although potential zwitterionic
interactions (e.g., such as in L-glutamic acid) may decrease
antimicrobial efficacy relative to similar compounds (e.g.,
glutaric acid, succinic acid) that do not comprise a-amino groups,
such zwitterionic compounds also exhibit antimicrobial activity. In
addition, two or more carboxylic acid groups in the polycarboxylic
acid-containing chelator compounds should be disposed in the
chelator compound in sufficient proximity to each other or the
compound should be capable of folding/conforming to bring the
carboxylic acids sufficiently close to facilitate chelation of
metal ions.
[0055] In certain embodiments, the chelator compound comprises an
aliphatic polycarboxylic acid or a salt thereof, an aromatic
polycarboxylic acid or a salt thereof, or a combination thereof. In
certain embodiments, the chelator compound comprises an aliphatic
portion. In certain embodiments, the chelator compound comprises an
aliphatic portion. The carboxylic acids may be disposed on the
aliphatic portion and/or on the aromatic portion. Nonlimiting
examples of chelator compounds that comprise an aliphatic portion
with a carboxylic acid group disposed thereon and an aromatic
portion with a carboxylic acid group disposed therein include
3-(2-carboxyphenyl)propionic acid, 3-(4-carboxyphenyl)propionic
acid, and 4-[(2-carboxyphenyl)amino]benzoic acid.
[0056] In certain embodiments, efficacy of the antimicrobial layer
can be improved by depositing a higher amount of dried
antimicrobial layer. Efficacy is dependent on concentration of
chelator compound in the antimicrobial layer as well as total
amount of the antimicrobial layer.
[0057] The antimicrobial layer may contain plasticizer. Suitable
plasticizers may include, for example, glycerol, a polyglycerol
having 2-20 glycerin units, polyglycerols partially esterified with
C.sub.1-C.sub.18 alkylcarboxylic acids having at least two free
hydroxyl groups (e.g., hexaglycerol monolaurate, decaglycerol
monolaurate, polyglyceryl-6 caprate, polyglyceryl-4 oleate,
polyglyceryl-10 trilaurate and the like), polyethylene oxide,
polyethylene glycol, polyethylene glycols initiated by any of the
glycols discussed herein such as polyethylene glycol glyceryl
ether, propylene glycol, dipropylene glycol, tripropylene glycol,
2-methyl-1,3-propanediol, sorbitol, dimethylisosorbide,
pentaerythritol, trimethylolpropane, ditrimethylolpropane, a random
ethylene oxide/propylene oxide (EO/PO) copolymer or oligomer, a
block EO/PO copolymer or oligomer, and combinations thereof.
[0058] Plasticizer may be present in the antimicrobial layer at
relatively high concentrations (on a weight basis). In some
embodiments, plasticizer comprises at least about 10 percent by
weight of the antimicrobial layer. In some embodiments, plasticizer
comprises at least about 10, 15, 20, 25, 30, 35, 40, 45, 50, 55,
60, 65, 70, or even at least 75 percent by weight of the
antimicrobial layer. In certain embodiments, the plasticizer
component can act as a humectant. Advantageously, this can maintain
a moist environment in a wound to help promote healing of wound
tissue.
[0059] Advantageously, the relatively high concentration of
plasticizer and/or water-soluble or water-dispersible polymer in
the antimicrobial layer can function as a controlled-release
modulator that facilitates delivery of the antimicrobial(s) over an
extended period of time. In some embodiments, the plasticizer
component can also function as an antimicrobial component.
[0060] Antimicrobial layers according to the present disclosure are
preferably solid at 25.degree. C. In certain embodiments, the
antimicrobial layer may comprise a solvent having a normal boiling
point of less than or equal to 100.degree. C. Nonlimiting examples
of such solvents include water and lower (C.sub.2-C.sub.5)
alcohols. Preferably, before use, the antimicrobial layer comprises
very little solvent (e.g., less than or equal to about 10 percent
by weight) having a normal boiling point of less than or equal to
100.degree. C. In some embodiments, the antimicrobial layer
comprises less than 5 percent by weight, less than 4 percent by
weight, less than 3 percent by weight, less than 2 percent by
weight, or even less than 1 percent by weight (by weight) of a
solvent having a normal boiling point of less than or equal to
100.degree. C. In certain embodiments, the antimicrobial layer may
be substantially free (before use) of such solvents or any
compounds having a normal boiling point of less than 100.degree.
C.
[0061] In many preferred embodiments, the antimicrobial layer(s)
comprise a water-soluble or water-dispersible polymer as a binder.
The water-soluble or water-dispersible polymer has a Tg greater
than or equal to 20.degree. C. In use, the polymer can function to
form the antimicrobial layer into a cohesive shape such as a film
while also absorbing wound exudate and to maintain a moist
environment that can facilitate healing of the tissue at a wound
site.
[0062] Exemplary water-soluble and/or water-dispersible polymers
that are suitable for use in a antimicrobial layer according to the
present disclosure include polyvinylpyrrolidone; polyvinyl alcohol;
copolymers of vinyl alcohol; polybutylenediol; polysaccharides
(e.g., starch); guar gum; locust bean gum; carrageenan; hyaluronic
acid; agar; alginate; tragacanth; gum arabic; gum karraya; gellan;
xanthan gum; hydroxyethylated, hydroxypropylated, and/or cationic
derivatives of the foregoing; modified cellulose polymers (e.g.,
hydroxyethylcellulose, hydroxypropyl methylcellulose,
carboxymethylcellulose, or cationic cellulose such as polyquaterium
4); copolymers of polyvinylpyrrolidone and vinyl acetate;
water-soluble and water-swellable polyacrylates (e.g., based on
hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate,
(meth)acrylic acid, (meth)acrylamide, PEG (meth)acrylates, methyl
(meth)acrylate), and combinations thereof. As used herein the term
"(meth)acryl" refers to acryl and/or methacryl. In certain
embodiments, the water-soluble or water-dispersible polymers can
comprise a polyquaternium polymer.
[0063] In some embodiments, the water-soluble or water-dispersible
polymer comprises at least about 5 percent by weight of the
antimicrobial layer. In some embodiments, the water-soluble or
water-dispersible polymer comprises up to about 65 percent by
weight of the antimicrobial layer.
[0064] The antimicrobial layers according to the present disclosure
preferably adhere well to the base fiber web and the wound-contact
scrim(s).
[0065] When contacting a wound site, the antimicrobial layer and/or
articles of the present disclosure are hydrated by the tissue
fluids and wound exudate Antimicrobial layers according to the
present disclosure comprise polycarboxylic acid chelator compounds
that, in an aqueous environment, have antimicrobial properties at
an acidic pH. Thus, antimicrobial layers of the present disclosure
comprise appropriate quantities of acidic components (e.g., the
free acid of the polycarboxylic acid chelator compound) and basic
components (e.g., NaOH or a salt of a polycarboxylic acid chelator
compound) such that the antimicrobial layer, when mixed well with
deionized water at a 1:9 mass ratio, forms an aqueous mixture
having a pH of about 2.5 to 5.5. In certain embodiments, the pH of
the resulting aqueous mixture is at least 2.5, 3.0, 3.5, 4.0, 4.5,
5.0, or even at least 5.5.
[0066] A variety of other ingredients may be added to the
antimicrobial layers according to the present disclosure for
desired effect. These include, but are not limited to, surfactants,
skin emollients and humectants such as, for example, those
described in U.S. Pat. No. 5,951,993 (Scholz et al.), fragrances,
colorants, and/or tackifiers.
[0067] Optionally a flexible adhesive barrier film is adhered to
and proximate to the second major side of the base fiber web.
Referring now to FIG. 2, wound dressing material 200 comprises base
fiber web 110 having first and second opposed major sides (112,
114). First wound-contact scrim 120a comprises copolymer fibers
comprising divalent hydroxyethylene monomer units and divalent
dihydroxybutylene monomer units. First antimicrobial layer 130a is
sandwiched between first major side 112 of base fiber web 110 and
first wound-contact scrim 120a. Flexible adhesive barrier film 140
is adhered to and proximate to second major side 114 of base fiber
web 110. In the particular embodiment shown, flexible adhesive
barrier film 140 extends beyond the periphery of the other
components such as the first wound contact scrim 120a, first
antimicrobial layer 130a, and base fiber web 110 so that it may
stick to the skin surrounding the wound, however this is not a
requirement. In this embodiment, the exposed adhesive side of the
adhesive barrier film may be protected by a disposable protective
releasable liner 160.
[0068] Commercially available suitable flexible adhesive barrier
films are marketed by 3M Company under the trade designation
TEGADERM (e.g., 3M TEGADERM Transparent Film Roll), by Johnson
& Johnson Company, New Brunswick, N.J. under the trade
designation BIOCLUSIVE, and by T. J. Smith & Nephew, Hull,
England under the trade designation OP-SITE.
[0069] Wound dressing materials according to the present disclosure
may have any basis weight, thickness, porosity, and/or density
unless otherwise specified. In some embodiments, the wound dressing
materials comprise a lofty open nonwoven fiber web.
[0070] Wound dressing materials according to the present disclosure
may have any desired thickness. In many embodiments, the thickness
is in the range of 0.5 to 6 mm, more preferably 0.75 to 5 mm, and
more preferably 1 to 4 mm. In many embodiments, the basis weight is
in the range of 100 to 1000 gsm, more preferably 150 to 900 gsm,
and more preferably 200 to 800 gsm. Likewise, the base fiber web
may have any basis weight, but in many embodiments, it is
preferably in the range of 20 to 500 gsm, more preferably 50 to 400
gsm, and more preferably 75 to 300 gsm.
[0071] The wound dressing material may be provided in roll form, or
it may be converted into sheets or bandages (optionally further
comprising a peripheral supporting frame).
[0072] Preferably, to maintain a low relative humidity, the wound
dressing material should be packaged in a package with a low
moisture vapor transmission rate (MVTR) such as, for example, a
Techni-Pouch package (Technipaq, Inc., Crystal Lake, Ill.) with a
PET/Aluminum Foil/LLDPE material construction.
[0073] Wound dressing materials according to the present disclosure
can be made by any suitable method, including, for example,
sequential or simultaneously pressure and/or heat lamination of the
wound-contact scrim(s), antimicrobial layer(s), fiber web, and
optional flexible adhesive barrier film. In some embodiments, the
antimicrobial layers may be coated (e.g., spray coated, roll
coated, curtain coated, or gravure coated), typically with an
associated drying step, onto either or both of the wound-contact
scrim(s) and the base fiber web. Such manufacturing techniques will
be apparent to those of ordinary skill in the art.
[0074] Wound dressing materials according to the present disclosure
are useful, for example, for covering a wound. Typically, exposed
surface of the wound is cleaned and/or treated with antiseptic (if
necessary) and then contacted with the first wound-contact scrim of
the wound dressing material, although this is not a requirement. In
some embodiments, the wound dressing material can be covered with a
secondary wound dressing.
Select Embodiments of the Present Disclosure
[0075] In a first embodiment, the present disclosure provides a
wound dressing material comprising:
[0076] a base fiber web having first and second opposed major
sides;
[0077] a first wound-contact scrim comprising first water-sensitive
fibers, wherein the first water-sensitive fibers comprise a first
copolymer comprising divalent hydroxyethylene monomer units and
divalent dihydroxybutylene monomer units; and
[0078] a first antimicrobial layer sandwiched between the first
major side of the base fiber web and the first wound-contact
scrim.
[0079] In a second embodiment, the present disclosure provides a
wound dressing material according to the first embodiment, further
comprising a flexible adhesive barrier film adhered to and
proximate to the second major side of the base fiber web.
[0080] In a third embodiment, the present disclosure provides a
wound dressing material according to the first or second
embodiment, further comprising:
[0081] a second wound-contact scrim comprising second
water-sensitive fibers, wherein the second water-sensitive fibers
comprise a second copolymer comprising divalent hydroxyethylene
monomer units and divalent dihydroxybutylene monomer units; and
[0082] a second antimicrobial layer sandwiched between the second
major side of the base fiber web and the second wound-contact
scrim.
[0083] In a fourth embodiment, the present disclosure provides a
wound dressing material according to any of the first to third
embodiments, wherein the first water-sensitive fibers are
multilayered and further comprise a polyurethane layer sandwiched
between two layers of copolymer comprising divalent hydroxyethylene
monomer units and divalent dihydroxybutylene monomer units.
[0084] In a fifth embodiment, the present disclosure provides a
wound dressing material according to any of the first to fourth
embodiments, wherein the first water-sensitive fibers have an
average fiber diameter of 2 to 100 microns.
[0085] In a sixth embodiment, the present disclosure provides a
wound dressing material according to any of the first to fifth
embodiments, wherein the first wound-contact scrim further
comprises secondary fibers comprising at least one of polyvinyl
alcohol, carboxymethyl cellulose, rayon, cotton, cellulose acetate,
thermoplastic polyurethane, chitosan, polyacrylic acid, sulfonated
cellulose, alginate, or cellulose ethyl sulfonate.
[0086] In a seventh embodiment, the present disclosure provides a
wound dressing material according to any of the first to fifth
embodiments, wherein the first wound-contact scrim further
comprises secondary fibers comprising at least one of polyethylene,
polypropylene, polybutylene, poly(ether ether ketone),
poly-4-methylpentene, polyethylene terephthalate, polyvinyl
chloride, polymethyl methacrylate, polyacrylonitrile, a polyamide,
a polyester, polystyrene, a styrenic block copolymer, a
polyurethane comprising polyethers, a block copolymers of
polyether, or polypropylene oxide.
[0087] In an eighth embodiment, the present disclosure provides a
wound dressing material according to any of the first to seventh
embodiments, wherein the base fiber web comprises base fibers
comprising at least one of polyolefin, polyester, polyvinyl
chloride, polymethyl methacrylate, polyacrylonitrile, polyamide,
polystyrene, or polyurethane.
[0088] In a ninth embodiment, the present disclosure provides a
wound dressing material according to any of the first to seventh
embodiments, wherein the base fiber web comprises base fibers
comprising at least one of polyvinyl alcohol, carboxymethyl
cellulose, rayon, cotton, cellulose acetate, thermoplastic
polyurethane, chitosan, polyacrylic acid, sulfonated cellulose,
alginate, or cellulose ethyl sulfonate.
[0089] In a tenth embodiment, the present disclosure provides a
wound dressing material according to any of the first to ninth
embodiments, wherein the first copolymer fibers further comprise
divalent acetoxyethylene monomer units.
[0090] In an eleventh embodiment, the present disclosure provides a
wound dressing material according to any of the first to tenth
embodiments, wherein the divalent dihydroxybutylene monomer units
comprise divalent 3,4-dihydroxybutan-1,2-diyl monomer units.
[0091] In a twelfth embodiment, the present disclosure provides a
wound dressing material according to any of the first to eleventh
embodiments, wherein the base fiber web comprises at least one of
polyolefin fibers, polyester fibers, polyamide fibers, styrenic
block copolymer fibers, polyurethane fibers, metal fibers, ceramic
fibers, or natural fibers.
[0092] In a thirteenth embodiment, the present disclosure provides
a wound dressing material according to any of the first to twelfth
embodiments, wherein the first wound-contact scrim is melt-blown or
spunbonded.
[0093] In a fourteenth embodiment, the present disclosure provides
a method of using a wound dressing material, the method comprising
contacting the first wound-contact scrim of a wound dressing
material according to any of the first to thirteenth embodiments
with an exposed surface (also including tissue exposed by surgery,
incision wounds, and tunneling wounds) of a wound.
[0094] In a fifteenth embodiment, the present disclosure provides a
method of making a wound dressing material, the method comprising
laminating sequential layers:
[0095] a) a first wound-contact scrim comprising water-sensitive
fibers, wherein the water-sensitive fibers comprise a first
copolymer comprising divalent hydroxyethylene monomer units and
divalent dihydroxybutylene monomer units;
[0096] b) a first antimicrobial layer; and
[0097] c) a base fiber web.
[0098] In a sixteenth embodiment, the present disclosure provides a
method of making a wound dressing material according to the
fifteenth embodiment, wherein the sequential layers further
comprise:
[0099] d) a second antimicrobial layer; and
[0100] e) a second wound-contact scrim comprising second
water-sensitive fibers, wherein the second water-sensitive fibers
comprise a second copolymer comprising divalent hydroxyethylene
monomer units and divalent dihydroxybutylene monomer units.
[0101] In a seventeenth embodiment, the present disclosure provides
a method of making a wound dressing material according to the
fifteenth embodiment, wherein the sequential layers further
comprise d) a flexible adhesive barrier film adhered to and
proximate to the second major side of the base fiber web.
[0102] In an eighteenth embodiment, the present disclosure provides
a method of making a wound dressing material according to any of
the fifteenth to seventeenth embodiments, wherein the sequential
layers are laminated simultaneously.
[0103] Objects and advantages of this disclosure are further
illustrated by the following non-limiting examples, but the
particular materials and amounts thereof recited in these examples,
as well as other conditions and details, should not be construed to
unduly limit this disclosure.
EXAMPLES
[0104] Unless otherwise noted, all parts, percentages, ratios, etc.
in the Examples and the rest of the specification are by
weight.
Preparation of Fiber Webs 1-14
[0105] Multicomponent blown microfiber (BMF) webs were made using a
melt-blowing process similar to that described in V. A. Wente,
"Superfine Thermoplastic Fibers" in Industrial Engineering
Chemistry, Vol. 48, pages 1342 et seq. (1956). The extruder feeding
molten (co)polymer to the melt-blowing die was a STEER 20-mm
twin-screw extruder (commercially available from the SteerAmerica
Corporation, Uniontown, Ohio), equipped with two weight loss
feeders to control the feeding of the (co)polymer resins to the
extruder barrel and a melt pump to control the (co)polymer melt
flow to a melt-blowing die. The die had a plurality of circular
smooth surfaced orifices (10 orifices/cm) with a 5:1 diameter ratio
as generally described in are described in, e.g., U.S. Pat. No.
5,232,770 (Joseph et al.).
[0106] The extruder was equipped with a multi-layer feed block
configured to produce multi-component blown micro-fibers that
exhibit an axial cross-sectional structure, when the fiber is
viewed in axial cross-section, consisting of three layers. BMF web
was made with each fiber having 3 layers. The inner layer of the
fiber was made of TECOPHILIC TPU TG2000 polyether polyurethane
(obtained from the Lubrizol Corporation, Wickliffe, Ohio) and the
outer layers were made using Nichigo G-Polymer butanediol vinyl
alcohol copolymer (BVOH) pellets (obtained as Nichigo G-Polymer OKS
8112) from the Mitsubishi Chemical Corporation, Tokyo, Japan.
[0107] The two extruders were kept at the same temperature at
210.degree. C. to deliver the melt stream to the melt-blowing die
(maintained at 210.degree. C.). The gear pumps were adjusted to
obtain either a 75/25 ratio or a 50/50 ratio of TECOPHILIC TPU
TG2000/BVOH. A total polymer throughput rate of 0.178 kg/hour/cm
die width (1.0 lb/hour/inch die width) was maintained at the
melt-blowing die. The primary air temperature was maintained at
approximately 325.degree. C.
[0108] The resulting web was collected at a BMF die to collector
distance of 58.4 cm. The resulting fibers had average fiber
diameters in the range of 5 to 30 micrometers.
[0109] Fiber webs 4-9 and 13-14 (Table 1) also contained
polyethylene terephthalate (PET) staple fibers (obtained from
Invista, Wichita, Kans.). The staple fibers were crimped with a
38.1 mm length and 3.3 dtex. Sufficient staple fibers were
dispensed in between the BMF die and the collector so as to
constitute either 10% or 30% by weight of the final nonwoven web.
Fiber webs 1-14 are further described in Table 1.
TABLE-US-00001 TABLE 1 NOMINAL BASIS PET WEIGHT STAPLE OF THE
3-LAYER FIBER FIBERS, COLLECTOR RESULTING Middle layer Outer Layers
% of SPEED, NONWOVEN FIBER wt. % wt. % nonwoven web ft/min WEB, WEB
TG2000 BVOH by weight (m/min) g/m.sup.2 1 75 25 0 4.7 (1.4) 207 2
75 25 0 9.4 (2.9) 112 3 75 25 0 18.8 (5.7) 56 4 75 25 10 5.5 (1.7)
205 5 75 25 10 11 (3.4) 93 6 75 25 10 22 (6.7) 45 7 75 25 30 6.8
(2.1) 186 8 75 25 30 13.6 (4.1) 91 9 75 25 30 27.2 (8.3) 45 10 50
50 0 4.5 (1.4) 193 11 50 50 0 9 (2.7) 105 12 50 50 0 18 (5.5) 50 13
50 50 30 6.6 (2.0) 141 14 50 50 30 13 (4.0) 90
Preparation of Fiber Web 15
[0110] A melt-blown (blown microfiber, BMF) nonwoven fiber web was
made using Nichigo G-Polymer butanediol vinyl alcohol copolymer
(BVOH) pellets (obtained as Nichigo G-Polymer OKS 8112 from the
Mitsubishi Chemical Corporation, Tokyo, Japan). A conventional
melt-blowing process was employed similar to that described in V.
A. Wente, "Superfine Thermoplastic Fibers" in Industrial
Engineering Chemistry, Vol. 48, pages 1342 et seq. (1956).
[0111] More particularly, the melt-blowing die had circular smooth
surfaced orifices, spaced 10 to the centimeter, with a 5:1 length
to diameter ratio. Molten (co)polymer was delivered to the die by a
20 mm twin screw extruder (commercially available from the
SteerAmerica Corporation). The extruder was equipped with two
weight loss feeders to control the feeding of the (co)polymer
resins to the extruder barrel, and a gear pump to control the
(co)polymer melt flow to a die. The extruder temperature was at
about 210.degree. C. and it delivered the melt stream to the BMF
die, which itself was maintained at 210.degree. C. The gear pump
was adjusted so that a 1.0 lb/hour/inch die width (0.18 kg/hour/cm
die width) (co)polymer throughput rate was maintained at the die.
The primary air temperature of the air knives adjacent to the die
orifices was maintained at approximately 325.degree. C. This
produced a web on a rotating collector spaced 10 cm from the die.
The speed of the collector was 7.1 meters/minute. The web had a
basis weight of approximately 40 gsm and a fiber diameter range of
5-25 micrometers.
Preparation of Fiber Web 16
[0112] A multicomponent BMF web was made using a melt blowing
process similar to that described in V. A. Wente, "Superfine
Thermoplastic Fibers" in Industrial Engineering Chemistry, Vol. 48,
pages 1342 et seq. (1956). The extruder feeding molten (co)polymer
to the melt-blowing die was a STEER 20-mm twin screw extruder
(commercially available from the SteerAmerica Corporation),
equipped with two weight loss feeders to control the feeding of the
(co)polymer resins to the extruder barrel and a melt pump to
control the (co)polymer melt flow to a melt-blowing die. The die
had a plurality of circular smooth surfaced orifices (10
orifices/cm) with a 5:1 diameter ratio as generally described in
are described in, e.g., U.S. Pat. No. 5,232,770 (Joseph et
al.).
[0113] The extruder was equipped with a multi-layer feed block
configured to produce multi-component blown micro-fibers that
exhibit an axial cross-sectional structure, when the fiber is
viewed in axial cross-section, consisting of three layers. A blown
microfiber (BMF) web was made with each fiber having 3 layers. The
inner layer of the fiber was made of TECOPHILIC TPU TG2000
(obtained from the Lubrizol Corporation) and the outer layers were
made using a blend of Dow DNDA 1081 Linear low-density polyethylene
(LLDPE) (obtained from the Dow Chemical Company, Midland, Mich.)
and UNITHOX 490 ethoxylate (obtained from the Baker Hughes Company,
Houston, Tex.).
[0114] The two extruders were kept at the same temperature at
210.degree. C. to deliver the melt stream to the BMF die
(maintained at 210.degree. C.). The gear pumps were adjusted to
obtain a 75/25 ratio of TECOPHILIC TPU TG2000/(LLDPE+6% UNITHOX 490
ethoxylate blend). The gear pump was adjusted so that a 0.178
kg/hour/cm die (1.0 lb/hour/inch die width) (co)polymer throughput
rate was maintained at the die. The primary air temperature of the
air knives adjacent to the die orifices was maintained at
approximately 325.degree. C. The BMF fibers were directed to a drum
collector and PET staple fibers were dispensed in between the BMF
die and drum collector. The staple fibers were crimped with a 38.1
mm length and 3.3 dtex (obtained from Invista, Wichita, Kans.).
Sufficient staple fibers were dispensed so as to constitute 30% by
weight of the final nonwoven web. The resulting web was collected
at a BMF die to collector distance of 58.4 cm and a collection rate
of 3.2 meters/minute. The web had a basis weight of approximately
116 gsm and a fiber diameter range of 5-30 micrometers.
Preparation of Fiber Web 17
[0115] Fiber Web 17 was prepared using the same procedure as
described for Fiber Web 15 with the exception that the collector
speed was 13.95 meters/minute, instead of 7.1 meters/minute. The
web had a basis weight of approximately 20 gsm and a fiber diameter
range of 5-25 micrometers. The web was compressed using a smooth
steel calendar operating at 200 psi (1.38 MPa), 1.5 meters/minute,
and 93.degree. C.
Preparation of Antimicrobial Composition for the Antimicrobial
Layer
[0116] An antimicrobial composition was prepared in a 100 g batch
using the components listed in Table 2. All of the components
except the L-PVPK60 were added to a MAX 100 mixing cup (Flacktec
Incorporated, Landrum, S.C.) and mixed at 3500 rpm (revolutions per
minute) for 1 minute using a DAC 400 FVZ SPEEDMIXER instrument
(Flacktec). The L-PVPK60 aqueous mixture was added to the cup and
the contents were mixed for 1 minute at 3500 rpm.
[0117] The viscous composition was knife-coated onto a release
liner using a gap of 254 micrometers. The coating was then dried at
80.degree. C. for 10 minutes in a convection oven to produce a
coating with a basis weight of 100 gsm.
TABLE-US-00002 TABLE 2 WEIGHT COMPONENT PERCENT SOURCE Glycerol 19
Cargill Corporation, Wayzata, Minnesota Linear polyvinylpyrrolidone
50 Ashland Incorporated, K60, 47% in water (L-PVPK60) Covington,
Kentucky Benzalkonium chloride 50% 0.3 Novo Nordisk Pharmatech,
(BAC) Koge, Denmark Capryl glycol (Hydrolite 8) 0.6 Symrise AG,
Holzminden, Germany Sterile water 12.6 Rocky Mountain Biologicals,
Missoula, Montana Sodium Citrate 10 MilliporeSigma, St. Louis,
Missouri Citric acid monohydrate 7.5 MilliporeSigma
Example 1
[0118] A section of Fiber Web 8 (Table 1), having a basis weight of
91 gsm and a fiber diameter range of 5-30 micrometers, was used as
the base fiber web in the wound dressing construction. The dried
antimicrobial composition (described above) was transferred from
the release liner to both sides of Fiber Web 8. The resulting Fiber
Web 8 coated on each side with an antimicrobial composition layer
was sandwiched between two sections of Fiber Web 9 (Table 1),
having a basis weight of 45 gsm and a fiber diameter range of 5-30
micrometers, to form a layered construction. The two sections of
Fiber Web 9 served as scrim components in the construction. The
layered sections were laminated together using hand pressure and
then needled using a Dilo DI-Loom OD-I 6 needle loom (DiloGroup,
Eberbach, Germany with Groz-Beckert 15.times.17.times.36.times.3 BA
needles (Groz-Beckert KG, Albstadt, Germany). The needling was
conducted at 8 feet/minute (2.4 meters/minute) with a 5% draw ratio
and 175 strokes/minute. The resulting needled construction was cut
into square sections (10.2 cm by 10.2 cm) to provide finished wound
dressing materials.
Example 2
[0119] A section of Fiber Web 16 (described above) was used as the
base fiber web in the wound dressing construction. The dried
antimicrobial composition (described above) was transferred from
the release liner to both sides of Fiber Web 16. The resulting
Fiber Web 16 coated on each side with an antimicrobial composition
layer was sandwiched between two sections of Fiber Web 15
(described above) to form a layered construction. The two sections
of Fiber Web 15 served as scrim components in the construction. The
layered sections were laminated together using hand pressure and
then needled using a Dilo DI-Loom OD-I 6 needle loom (DiloGroup,
Eberbach, Germany with Groz-Beckert 15.times.17.times.36.times.3 BA
needles (Groz-Beckert KG, Albstadt, Germany). The needling was
conducted at 8 feet/minute (2.4 meters/minute) with a 5% draw ratio
and 175 strokes/minute. The resulting needled construction was cut
into square sections (10.2 cm by 10.2 cm) to provide finished wound
dressing materials.
Example 3
[0120] A section of Fiber Web 16 (described above) was used as the
base fiber web in the wound dressing construction. The dried
antimicrobial composition (described above) was transferred from
the release liner to one side of Fiber Web 16. A section of Fiber
Web 17 (described above) was placed over the antimicrobial coated
surface of Fiber Web 16. Fiber Web 17 served as scrim component in
the construction. The layers were laminated together using hand
pressure and the construction was cut into square sections (10.2 cm
by 10.2 cm) to make finished wound dressing materials
Example 4
[0121] A finished wound dressing material from Example 3 was placed
on a hard flat surface with the scrim layer of the construction
facing the surface. A 6 inch by 6 inch square section of
transparent barrier film was cut from a roll of 6 inch wide 3M
TEGADERM transparent barrier film (obtained from 3M Company) and
the backing layer was removed to expose the adhesive surface of the
barrier film. The barrier film was centered with respect to the
wound dressing material and adhesively adhered to base fiber web
surface of the wound dressing material (i.e., adhesive surface of
the ILGADERM barrier film in contact with the base fiber web). In
this construction, the barrier film extended beyond the outer edges
of the scrim and the base fiber web.
* * * * *