U.S. patent application number 15/554309 was filed with the patent office on 2018-03-22 for antimicrobial fibers.
This patent application is currently assigned to MITSUBISHI GAS CHEMICAL COMPANY, INC.. The applicant listed for this patent is MITSUBISHI GAS CHEMICAL COMPANY, INC.. Invention is credited to Akira ITO.
Application Number | 20180080149 15/554309 |
Document ID | / |
Family ID | 56918820 |
Filed Date | 2018-03-22 |
United States Patent
Application |
20180080149 |
Kind Code |
A1 |
ITO; Akira |
March 22, 2018 |
ANTIMICROBIAL FIBERS
Abstract
The invention provides an antimicrobial fiber which exhibits
excellent antimicrobial properties even without the addition of
antimicrobial agents and can remain antimicrobial even after
repeated washing. The antimicrobial fiber comprises a fiber having
on a surface thereof a polyacetal copolymer (X) containing
oxyalkylene groups, the molar amount of oxyalkylene groups in the
polyacetal copolymer (X) being 0.2 to 5 mol % relative to the total
of the molar amount of oxymethylene groups and the molar amount of
oxyalkylene groups.
Inventors: |
ITO; Akira; (Tokyo,
JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
MITSUBISHI GAS CHEMICAL COMPANY, INC. |
Tokyo |
|
JP |
|
|
Assignee: |
MITSUBISHI GAS CHEMICAL COMPANY,
INC.
Tokyo
JP
|
Family ID: |
56918820 |
Appl. No.: |
15/554309 |
Filed: |
March 10, 2016 |
PCT Filed: |
March 10, 2016 |
PCT NO: |
PCT/JP2016/057513 |
371 Date: |
August 29, 2017 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A41D 31/30 20190201;
A63H 3/02 20130101; A41B 2500/30 20130101; A41B 11/00 20130101;
A41D 13/04 20130101; A41D 19/00 20130101; A41D 25/00 20130101; D04B
1/16 20130101; C08L 59/04 20130101; A41B 11/14 20130101; A41B
2400/34 20130101; D03D 15/00 20130101; D04B 21/00 20130101; A41B
15/00 20130101; A41D 31/00 20130101; A41B 2500/10 20130101; C08G
2/22 20130101; A47G 9/0238 20130101; A41B 1/08 20130101; A41D 23/00
20130101; D10B 2321/06 20130101; D01F 6/66 20130101; A41B 2500/20
20130101; D01F 8/16 20130101; D04H 1/4326 20130101; A41B 17/00
20130101; A41D 2600/10 20130101 |
International
Class: |
D03D 15/00 20060101
D03D015/00; C08L 59/04 20060101 C08L059/04; C08G 2/22 20060101
C08G002/22; D01F 8/16 20060101 D01F008/16; D01F 6/66 20060101
D01F006/66; D04B 1/16 20060101 D04B001/16; D04B 21/00 20060101
D04B021/00; A41D 31/00 20060101 A41D031/00 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 18, 2015 |
JP |
2015-054267 |
Claims
1. An antimicrobial fiber comprising a fiber having a polyacetal
copolymer (X) on a surface thereof, the polyacetal copolymer (X)
having oxymethylene groups and oxyalkylene groups of the following
general formula (1), the molar amount of the oxyalkylene groups in
the polyacetal copolymer (X) being 0.2 to 5 mol % relative to the
total of the molar amount of the oxymethylene groups and the molar
amount of the oxyalkylene groups, ##STR00003## wherein R.sub.0 and
R.sub.0', which may be the same as or different from each other,
are each selected from a hydrogen atom, a C.sub.1-8 alkyl group, an
organic group having a C.sub.1-8 alkyl group, a phenyl group and an
organic group having a phenyl group, and m is an integer of 2 to
6.
2. The antimicrobial fiber according to claim 1, wherein the
orientation factor of the polyacetal copolymer (X) is not less than
60%.
3. The antimicrobial fiber according to claim 1, wherein the fiber
having the polyacetal copolymer (X) on a surface thereof is a
monolayer fiber of the polyacetal copolymer (X).
4. The antimicrobial fiber according to claim 1, wherein the fiber
having the polyacetal copolymer (X) on a surface thereof is a
multilayer fiber having a coating of the polyacetal copolymer (X)
on a fiber including a thermoplastic resin.
5. The antimicrobial fiber according to claim 1, wherein the fiber
having the polyacetal copolymer (X) on a surface thereof is a
conjugate fiber having the polyacetal copolymer (X) on a surface of
a fiber including a thermoplastic resin.
6. The antimicrobial fiber according to claim 4, wherein the
thermoplastic resin is one or more selected from polyacetal
homopolymers, polyacetal copolymers other than the polyacetal
copolymer (X), polyolefin resins, polylactic acid resins, nylon
resins, polyester resins, polyvinyl resins and elastomers of these
resins.
7. A nonwoven fabric comprising the antimicrobial fiber according
to claim 1.
8. A filter comprising the nonwoven fabric according to claim
7.
9. A knitted fabric comprising the antimicrobial fiber according to
claim 1.
10. A woven fabric comprising the antimicrobial fiber according to
claim 1.
11. A felt comprising the antimicrobial fiber according to claim
1.
12. A web comprising the antimicrobial fiber according to claim
1.
13. A clothing article comprising one or more selected from the
group consisting of the knitted fabrics, the woven fabrics, the
felts and the webs according to claim 9.
14. A bedding article comprising one or more selected from the
group consisting of the knitted fabrics, the woven fabrics, the
felts and the webs according to claim 9.
15. An interior article comprising one or more selected from the
group consisting of the knitted fabrics, the woven fabrics, the
felts and the webs according to claim 9.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to an antimicrobial fiber
having a polyacetal copolymer on its surface. The invention also
relates to a nonwoven fabric, a knitted fabric, a woven fabric, a
felt and a web which each include the antimicrobial fiber. Further,
the invention relates to a filter including the nonwoven fabric,
and to a clothing article, a bedding article or an interior article
including any one or more selected from the group consisting of the
knitted fabrics, the woven fabrics, the felts and the webs.
BACKGROUND ART
[0002] Polyacetal is an engineering plastic with excellent
mechanical properties, heat resistance, chemical resistance and
electrical characteristics, and is widely used in fields such as
electric appliances, automobiles, machinery and building materials.
Further, polyacetal is easy to fabricate into articles and is used
as fibers, nonwoven fabrics and filters (see, for example, Patent
Literatures 1 to 3).
[0003] With the social development, plastics have been increasingly
required to be resistant to microbes (to have antimicrobial
properties) in addition to having the properties described above.
Because of their nature as dielectric materials or electrically
insulating materials, however, plastics are prone to attract
airborne dusts and microbes and tend to allow microbes to grow on
their surfaces if the temperature and humidity conditions are
appropriate. The growth of microbes deteriorates the appearance and
causes a bad odor, and microbes contaminate objects that have
touched them. For example, Moraxella osloensis is known to be the
cause of 4-methyl-3-hexenoic acid which is responsible for the
rag-like smell of washed clothes.
[0004] A known approach to improving the antimicrobial properties
of plastics is to knead into the plastics an organic antimicrobial
agent such as 2-(4-thiazolyl)-benzimidazole (thiabendazole) or an
inorganic antimicrobial agent such as a substance containing metal
ions, for example, silver, copper or zinc ions, or to coat the
surface of plastic articles with such an organic antimicrobial
agent or inorganic antimicrobial agent (see, for example, Patent
Literatures 4 and 5).
[0005] Methods which improve antimicrobial properties are also
presented for polyacetal. For example, Patent Literature 4
discloses a resin composition in which a metal ion-containing
substance such as zinc benzoate, zinc sulfate or zinc oxide is
melt-kneaded into polyacetal. Patent Literature 5 discloses a resin
composition in which a poly-.beta.-alanine polymer and an inorganic
antimicrobial zeolite are melt-kneaded into polyacetal. Further,
Patent Literature 6 discloses a resin composition in which a
specific hindered amine substance such as dimethyl
succinate-1-(2-hydroxyethyl)-4-hydroxy-2,2,6,6-tetramethylpiperi-
dine polycondensate is melt-kneaded into polyacetal.
PRIOR ART DOCUMENTS
Patent Documents
[0006] Patent Literature 1: Japanese Patent Laid-Open No.
2008-163505
[0007] Patent Literature 2: Japanese Patent Laid-Open No.
2004-360146
[0008] Patent Literature 3: Japanese Patent Laid-Open No.
2005-13829
[0009] Patent Literature 4: Japanese Patent Laid-Open No.
H5-230325
[0010] Patent Literature 5: Japanese Patent Laid-Open No.
H9-291193
[0011] Patent Literature 6: Japanese Patent Laid-Open No.
H10-265585
SUMMARY OF THE INVENTION
Problems to be Solved by the Invention
[0012] Organic antimicrobial agents frequently have problems in
terms of aspects such as appearance, heat resistance, safety (for
example, carcinogenicity and atopicity) and resin affinity. For
example, the aforementioned thiabendazole, when mixed with
plastics, shows a very high tendency to bleed out and thus cannot
be expected to provide persistent antimicrobial effects
(antimicrobial properties). Further, it is known that bleeding
causes problems such as the surface of articles being white bloomy
or the surface of articles being sticky. From the safety viewpoint,
it is known that the compound is carcinogenic. Furthermore, organic
antimicrobial agents have another problem in that they are easily
decomposed by heat when being melt-kneaded with plastic materials
(see, for example, Patent Literature 4).
[0013] On the other hand, some problems encountered with inorganic
antimicrobial agents are that the antimicrobial agents need to be
added in large amounts (for example, 1 to 2 wt %) to plastics in
order to provide antimicrobial effects, that the antimicrobial
agents are detached from plastics due to friction or the like to
fail to provide persistent effects, and that the antimicrobial
agents are dissolved by contact with water and solvents.
[0014] An object of the present invention is to provide an
antimicrobial fiber which has excellent antimicrobial properties
and can remain antimicrobial even after repeated washing. Another
object is to provide a nonwoven fabric, a knitted fabric, a woven
fabric, a felt and a web which each include the antimicrobial fiber
described above and exhibit excellent antimicrobial properties. A
further object of the invention is to provide a filter including
the nonwoven fabric, and a clothing article, a bedding article or
an interior article which includes any one or more selected from
the group consisting of the knitted fabrics, the woven fabrics, the
felts and the webs.
Means for Solving the Problems
[0015] As a result of extensive studies on the problems discussed
above, the present inventor has found that a fiber which has on its
surface a polyacetal copolymer containing a specific amount of
oxyalkylene groups attains excellent antimicrobial properties and
remains antimicrobial even after repeated washing, thus completing
the present invention.
[0016] Specifically, the present invention pertains to the
following.
[0017] (1) An antimicrobial fiber including a fiber having a
polyacetal copolymer (X) on a surface thereof, the polyacetal
copolymer (X) having oxymethylene groups and oxyalkylene groups of
the following general formula (1), the molar amount of the
oxyalkylene groups in the polyacetal copolymer (X) being 0.2 to 5
mol % relative to the total of the molar amount of the oxymethylene
groups and the molar amount of the oxyalkylene groups,
##STR00001##
[0018] wherein R.sub.0 and R.sub.0', which may be the same as or
different from each other, are each selected from a hydrogen atom,
a C.sub.1-8 alkyl group, an organic group having a C.sub.1-8 alkyl
group, a phenyl group and an organic group having a phenyl group,
and m is an integer of 2 to 6.
[0019] (2) The antimicrobial fiber described in (1), wherein the
orientation factor of the polyacetal copolymer (X) is not less than
60%.
[0020] (3) The antimicrobial fiber described in (1) or (2), wherein
the fiber having the polyacetal copolymer (X) on a surface thereof
is a monolayer fiber of the polyacetal copolymer (X).
[0021] (4) The antimicrobial fiber described in (1) or (2), wherein
the fiber having the polyacetal copolymer (X) on a surface thereof
is a multilayer fiber having a coating of the polyacetal copolymer
(X) on a fiber including a thermoplastic resin.
[0022] (5) The antimicrobial fiber described in (1) or (2), wherein
the fiber having the polyacetal copolymer (X) on a surface thereof
is a conjugate fiber having the polyacetal copolymer (X) on a
surface of a fiber including a thermoplastic resin.
[0023] (6) The antimicrobial fiber described in (4) or (5), wherein
the thermoplastic resin is one or more selected from polyacetal
homopolymers, polyacetal copolymers other than the polyacetal
copolymer (X), polyolefin resins, polylactic acid resins, nylon
resins, polyester resins, polyvinyl resins and elastomers of these
resins.
[0024] (7) A nonwoven fabric including the antimicrobial fiber
described in any one of (1) to (6).
[0025] (8) A filter including the nonwoven fabric described in
(7).
[0026] (9) A knitted fabric including the antimicrobial fiber
described in any one of (1) to (6).
[0027] (10) A woven fabric including the antimicrobial fiber
described in any one of (1) to (6).
[0028] (11) A felt including the antimicrobial fiber described in
any one of (1) to (6).
[0029] (12) A web including the antimicrobial fiber described in
any one of (1) to (6).
[0030] (13) A clothing article including one or more selected from
the group consisting of the knitted fabrics, the woven fabrics, the
felts and the webs described in (9) to (12).
[0031] (14) A bedding article including one or more selected from
the group consisting of the knitted fabrics, the woven fabrics, the
felts and the webs described in (9) to (12).
[0032] (15) An interior article including one or more selected from
the group consisting of the knitted fabrics, the woven fabrics, the
felts and the webs described in (9) to (12).
Effects of Invention
[0033] According to the present invention, an antimicrobial fiber
can be provided which has excellent antimicrobial properties and
can remain antimicrobial even after repeated washing. The
antimicrobial fiber of the invention can be fabricated into a
nonwoven fabric, a knitted fabric, a woven fabric, a felt and a web
which exhibit excellent antimicrobial properties. Thus, the
invention can provide a filter, a clothing article, a bedding
article and an interior article which each include any of the above
fabricated products and have excellent antimicrobial
properties.
EMBODIMENTS TO CARRY OUT THE INVENTION
[0034] <Antimicrobial Fibers>
[0035] The present invention will be described in detail
hereinbelow. An aspect of the invention resides in an antimicrobial
fiber which comprises a fiber having a polyacetal copolymer (X) on
a surface thereof. The polyacetal copolymer (X) has oxymethylene
groups and oxyalkylene groups of the general formula (1) described
later. The molar amount of the oxyalkylene groups in the polyacetal
copolymer (X) is 0.2 to 5 mol % relative to the total of the molar
amount of the oxymethylene groups and the molar amount of the
oxyalkylene groups. That is, the antimicrobial fiber of the
invention is characterized in that the fiber has on a surface
thereof a polyacetal copolymer (X) which contains 0.2 to 5 mol % of
oxyalkylene groups of the general formula (1) described later
relative to the total of the molar amount of oxymethylene groups
and the molar amount of oxyalkylene groups.
[0036] The antimicrobial fiber of the invention is a fiber having
the polyacetal copolymer (X) on a surface thereof. The fiber may
have the polyacetal copolymer (X) on a surface thereof in any
configuration without limitation. Preferably, the fiber is [A] a
monolayer fiber of the polyacetal copolymer (X), [B] a multilayer
fiber having a coating of the polyacetal copolymer (X) on a fiber
comprising a thermoplastic resin, or [C] a conjugate fiber having
the polyacetal copolymer (X) on a surface of a fiber comprising a
thermoplastic resin.
[0037] The monolayer fiber [A] of the polyacetal copolymer (X) is a
fiber comprising the polyacetal copolymer (X). The monolayer fiber
may be obtained by melt-spinning the polyacetal copolymer (X) and
optionally drawing the fiber as required.
[0038] In the multilayer fiber [B] having a coating of the
polyacetal copolymer (X) on a surface, the core may be a fiber
comprising a thermoplastic resin. The type of the thermoplastic
resin is not particularly limited. Examples of the thermoplastic
resin include polyacetal homopolymers, polyacetal copolymers other
than the polyacetal copolymer (X) (for example, polyacetal
copolymers containing more than 5 mol % of oxyalkylene groups of
the general formula (1) relative to the total of the molar amount
of oxymethylene groups and the molar amount of oxyalkylene groups),
polyolefin resins, polylactic acid resins, nylon resins, polyester
resins, polyvinyl resins and elastomers of these resins. These
thermoplastic resins may be used singly, or two or more may be used
as a stack or a compatibilized resin. The term "coating" used in
the present invention means that the entirety or a portion of the
surface of the core fiber parallel to the fiber direction is
covered. The proportion of the coating on the surface is not
particularly limited, but a higher proportion is more preferable
because excellent antimicrobial properties are attained.
[0039] The multilayer fiber may be obtained by melt-spinning the
polyacetal copolymer (X) and the aforementioned thermoplastic resin
and optionally drawing the fiber as required. The resultant
multilayer fiber has a sheath-core structure in which the
polyacetal copolymer (X) covers the entirety or a portion of the
periphery of a fiber comprising the thermoplastic resin as the core
fiber.
[0040] In the conjugate fiber [C] having the polyacetal copolymer
(X) on a surface of a fiber comprising a thermoplastic resin, the
type of the thermoplastic resin is not particularly limited and may
be similar to the thermoplastic resin in the multilayer fiber
configuration described above. The thermoplastic resins may be used
singly, or two or more may be used as a stack or a compatibilized
resin.
[0041] The conjugate fiber having the polyacetal copolymer (X) on a
surface of a fiber comprising a thermoplastic resin may be obtained
by melt-spinning a mixture of the polyacetal copolymer (X) and the
aforementioned thermoplastic resin, and optionally drawing the
fiber as required. The resultant conjugate fiber may be such that
the polyacetal copolymer (X) is exposed on the fiber surface on the
polymer molecular level by being compatibilized with the
thermoplastic resin, or such that the polyacetal copolymer (X) is
exposed on the fiber surface while forming an islands-sea structure
or other dispersed phases derived from such a structure, or such
that the polyacetal copolymer (X) and the thermoplastic resin are
exposed on the surface side by side. The proportion in which the
polyacetal copolymer (X) is exposed on the surface of the conjugate
fiber is not particularly limited, but a higher proportion is more
preferable because excellent antimicrobial properties are
attained.
[0042] In the antimicrobial fiber of the invention, the orientation
factor of the polyacetal copolymer (X) is not particularly limited,
but is preferably not less than 60%, more preferably not less than
70%, and particularly preferably not less than 80%. The reason for
this preference is that the antimicrobial properties are enhanced
with increasing orientation factor of the polyacetal copolymer (X).
As will be described later, the antimicrobial properties of the
polyacetal copolymer (X) are correlated with the amount of
oxyalkylene groups contained in the copolymer, and the polyacetal
copolymer (X) tends to decrease its antimicrobial properties as the
content of oxyalkylene groups is increased. However, the
orientation factor comes to have a greater impact on the
antimicrobial properties as the content of oxyalkylene groups in
the polyacetal copolymer (X) is higher. Because of this
characteristic, a higher orientation factor provides higher
antimicrobial properties when the polyacetal copolymer (X) has a
high content of oxyalkylene groups. The orientation factor of the
polyacetal copolymer (X) may be efficiently increased by drawing
the fiber that has been melt-spun.
[0043] The orientation factor of the antimicrobial fiber may be
determined using a wide angle X-ray diffractometer as will be
described in Examples in the present specification.
[0044] The acceptable monofilament fineness of the antimicrobial
fiber of the invention is variable depending on the purpose of use,
and thus the monofilament fineness is not particularly limited.
When the fiber is used as a filter, the fineness is preferably not
more than 10 dtex (unit: decitex) because of the need of increasing
the filtration accuracy while reducing the pressure loss of the
fluid.
[0045] In the case of Staphylococcus aureus known as a bacterium
responsible for food poisoning, the bacteriostatic activity of the
antimicrobial fiber of the invention, as measured by an
antimicrobial test in accordance with JIS L 1902 (Testing for
antibacterial activity and efficacy on textile products) is usually
not less than 2.2, preferably not less than 2.4, and particularly
preferably not less than 2.7. This activity value qualifies for the
certification as being antimicrobial and deodorant finished that is
established by Japan Textile Evaluation Technology Council. The
antimicrobial fiber of the invention is also characterized by its
high bactericidal activity on Staphylococcus aureus. Another
outstanding characteristic is that such antimicrobial properties
persist even after repeated washing as compared to antimicrobial
fibers obtained by kneading antimicrobial substances into
polyacetal fibers.
[0046] The antimicrobial fiber of the invention exhibits high
bacteriostatic activity also on Moraxella osloensis which causes a
bad smell. The bacteriostatic activity on Moraxella osloensis is
usually not less than 1.8, preferably not less than 2.0, and
particularly preferably not less than 2.2. The antimicrobial fiber
of the invention is also characterized by its high bactericidal
activity on Moraxella osloensis. Another outstanding characteristic
is that such antimicrobial properties persist even after repeated
washing as compared to antimicrobial fibers obtained by kneading
antimicrobial substances into polyacetal fibers.
[0047] <Methods for Producing Antimicrobial Fibers>
[0048] The antimicrobial fiber of the invention may be produced by
a known fiber production method. For example, the fiber may be
produced by melt-spinning, for example, pellets of the polyacetal
copolymer (X). During the production, it is preferable to draw the
fiber that has been melt-spun so as to increase the orientation
factor described hereinabove. The drawing may be performed by a
known method under known conditions. The draw ratio is preferably 3
times or more from the point of view of orientation factor. The
upper limit of the draw ratio is not limited from the point of view
of orientation factor, but is 15 times to ensure stability during
production (to prevent filament breakage) and to prevent excessive
fibril formation. The apparatuses for melt-spinning and drawing may
be conventional apparatuses.
[0049] <Polyacetal Copolymers (X)>
[0050] The polyacetal copolymer (X) present on a surface of the
antimicrobial fiber of the invention has, in the molecule,
oxymethylene groups (--CH.sub.2--O--) and oxyalkylene groups having
a structure of the following general formula (1):
##STR00002##
[0051] In the formula, R.sub.0 and R.sub.0', which may be the same
as or different from each other, are each selected from a hydrogen
atom, a C.sub.1-8 alkyl group, an organic group having a C.sub.1-8
alkyl group, a phenyl group and an organic group having a phenyl
group. The letter m is an integer of 2 to 6. Preferably, R.sub.0
and R.sub.0' may be the same as or different from each other and
are each selected from a hydrogen atom, a C.sub.1-4 alkyl group, a
C.sub.1-4 alkoxy group, a phenyl group and a benzyl group, and m is
an integer of 2 to 4. More preferably, R.sub.0 and R.sub.0' are
each selected from a hydrogen atom and a C.sub.1-4 alkyl group, and
m is 2.
[0052] Examples of the C.sub.1-8 alkyl groups include methyl group,
ethyl group, propyl group, isopropyl group, butyl group, isobutyl
group, pentyl group, hexyl group and cyclohexyl group. Examples of
the organic groups having a C.sub.1-8 alkyl group include methoxy
group, ethoxy group, propoxy group, isopropoxy group and butoxy
group. Examples of the organic groups having a phenyl group include
benzyl group and phenethyl group.
[0053] Preferred oxyalkylene groups are oxyethylene groups,
oxypropylene groups and oxybutylene groups. Oxyethylene groups are
particularly preferable.
[0054] A single kind, or two or more kinds of the oxyalkylene
groups may be present in the polyacetal copolymer (X). That is, the
polyacetal copolymer (X) of the invention may be a binary copolymer
or a multicomponent copolymer.
[0055] The polyacetal copolymer (X) of the invention may be a
polyacetal copolymer which further has a block structure other than
the oxymethylene groups and the oxyalkylene groups, or may be a
polyacetal copolymer which further has a branch structure in the
molecule. Examples of such polyacetal copolymers include a
polyacetal copolymer which is obtained using as a chain transfer
agent a thermoplastic resin or an oligomer that has an active
hydrogen-containing functional group such as a hydroxyl group at a
molecular end or within the molecule and which has the structure of
the chain transfer agent introduced at a molecular end; and a
polyacetal copolymer which is obtained by polymerization reaction
in the presence of a compound that contains, in the main chain, a
copolymerizable cyclic formal moiety such as polyvinyl formal.
[0056] The polyacetal copolymer (X) of the invention may be one
produced using a termonomer such as an epoxy compound, for example,
glycidyl ether, or allyl ether, or the polyacetal copolymer may
have a structure derived from such a compound.
[0057] The range of the content of oxyalkylene groups (the molar
amount of oxyalkylene groups) in general polyacetal copolymers is
as wide as from 0.01 to 20 mol % relative to the total of the molar
amount of oxymethylene groups and the molar amount of oxyalkylene
groups. In contrast, the content of oxyalkylene groups (the molar
amount of oxyalkylene groups) in the inventive polyacetal copolymer
(X) is usually 0.2 to 5 mol % relative to the total of the molar
amount of oxymethylene groups and the molar amount of oxyalkylene
groups, and is preferably 0.2 to 3.0 mol %, more preferably 0.2 to
2.0 mol %, and particularly preferably 0.2 to 1.0 mol %. When the
content of oxyalkylene groups is not less than 0.2 mol % and not
more than 5 mol %, the copolymer attains excellent antimicrobial
properties and exhibits high bacteriostatic activity which shows
antimicrobial properties, and is resistant to a decrease in
bacteriostatic activity even when subjected to repeated washing.
When the content of oxyalkylene groups is not less than 0.2 mol %
and not more than 3.0 mol %, the copolymer attains higher
antimicrobial properties and exhibits higher bacteriostatic
activity which shows antimicrobial properties, and is more
resistant to a decrease in bacteriostatic activity even when
subjected to repeated washing.
[0058] The polyacetal copolymer (X) of the invention that is used
may be a single such copolymer or may be a combination of two or
more polyacetal copolymers having different kinds of oxyalkylene
groups or a combination of two or more polyacetal copolymers having
different contents of oxyalkylene groups. When two or more
polyacetal copolymers having different kinds of oxyalkylene groups
or different contents of oxyalkylene groups are used in
combination, these polyacetal copolymers may be in the
compatibilized state, may form an islands-sea structure or other
dispersed phases derived from such a structure, or may have a
side-by-side configuration or the like.
[0059] The polyacetal copolymer (X) of the invention preferably has
an MVR (melt volume rate) in accordance with ISO 1133 of not more
than 100 cm.sup.3/10 min. While a higher MVR value is more suited
for the production of fine fibers by melt-spinning, 100 cm.sup.3/10
mm or less melt volume rate ensures that the obtainable fiber
attains excellent mechanical properties (in particular,
toughness).
[0060] <Methods for Producing Polyacetal Copolymers (X)>
[0061] The polyacetal copolymer (X) of the invention may be
produced by any method that is known and conventional. For example,
a polyacetal resin having oxymethylene groups and C.sub.2-4
oxyalkylene groups as structural units may be produced by
copolymerizing a cyclic acetal formed by oxymethylene groups such
as formaldehyde trimer (trioxane) or tetramer (tetraoxane), with a
cyclic acetal containing a C.sub.2-4 oxyalkylene group such as
ethylene oxide, 1,3-dioxolane, 1,3,6-trioxocane or 1,3-dioxepane.
In particular, the polyacetal copolymer (X) of the invention is
preferably a copolymer of a cyclic acetal such as trioxane or
tetraoxane, and ethylene oxide or 1,3-dioxolane, and is
particularly preferably a copolymer of trioxane and
1,3-dioxolane.
[0062] For example, the polyacetal copolymer (X) of the invention
may be obtained by bulk polymerization of a cyclic acetal formed by
oxymethylene groups with a cyclic acetal comonomer containing a
C.sub.2-4 oxyalkylene group in the presence of a polymerization
catalyst. A reaction terminator may be used as required to
deactivate the polymerization catalyst and the growing ends of the
polymer. Further, a molecular weight modifier may be used as
required to control the molecular weight of the polyacetal
copolymer. The types and amounts of the polymerization catalyst,
the reaction terminator and the molecular weight modifier which may
be used in the production of the polyacetal copolymer (X) of the
invention are not particularly limited as long as the advantageous
effects of the invention are not impaired. Any known polymerization
catalysts, reaction terminators and molecular weight modifiers may
be used appropriately.
[0063] The polymerization catalysts are not particularly limited.
Examples thereof include Lewis acids such as boron trifluoride, tin
tetrachloride, titanium tetrachloride, phosphorus pentachloride,
phosphorus pentafluoride, arsenic pentafluoride and antimony
pentafluoride, and complex compounds or salt compounds of these
Lewis acids. Examples further include protonic acids such as
trifluoromethanesulfonic acid and perchloric acid; protonic acid
esters such as esters of perchloric acid with lower aliphatic
alcohols; and protonic acid anhydrides such as mixed anhydrides of
perchloric acid with lower aliphatic carboxylic acids. Examples
further include triethyloxonium hexafluorophosphate,
triphenylmethyl hexafluoroarsenate, acetyl hexafluoroborate,
heteropoly acids or acidic salts thereof, isopoly acids or acidic
salts thereof, and perfluoroalkylsulfonic acids or acidic salts
thereof. In particular, compounds containing boron trifluoride are
preferable, and coordination complexes thereof with ethers,
specifically, boron trifluoride diethyl etherate and boron
trifluoride dibutyl etherate are particularly preferable.
[0064] The amount of the polymerization catalyst is not
particularly limited, but is usually in the range of
1.0.times.10.sup.-8 to 2.0.times.10.sup.-3 mol per 1 mol of all the
monomers including trioxane and comonomer(s), and is preferably
5.0.times.10.sup.-8 to 8.0.times.10.sup.-4 mol, and particularly
preferably 5.0.times.10.sup.-8 to 1.0.times.10.sup.-4 mol.
[0065] The reaction terminator is not particularly limited.
Examples thereof include trivalent organic phosphorus compounds,
amine compounds, and hydroxides of alkali metals or alkaline earth
metals. These reaction terminators may be used singly, or two or
more may be used in combination. In particular, trivalent organic
phosphorus compounds, tertiary amines and hindered amines are
preferable.
[0066] The amount of the reaction terminator is not particularly
limited as long as the amount is sufficient to deactivate the
polymerization catalyst. The molar ratio thereof to the
polymerization catalyst is usually in the range of
1.0.times.10.sup.-1 to 1.0.times.10.sup.1.
[0067] The molecular weight modifier is not particularly limited.
Examples thereof include methylal, methoxymethylal,
dimethoxymethylal, trimethoxymethylal and oxymethylene di-n-butyl
ether. In particular, methylal is preferable. The amount of the
molecular weight modifier is determined appropriately in accordance
with the target molecular weight. The amount is usually controlled
in the range of 0 to 0.1 mass % relative to all the monomers.
[0068] <Optional Components and Additional Components which May
be Present in Polyacetal Copolymer (X)>
[0069] When carrying out the present invention, hindered phenol
compounds, hindered amine compounds, amino-substituted triazine
compounds, phosphorus stabilizers, and metal-containing compounds
represented by the group consisting of hydroxides, fatty acid
salts, inorganic acid salts or alkoxides of alkali metals and
alkaline earth metals, may be added to the polyacetal copolymer (X)
of the invention while still achieving the original objects. In the
present specification, the "hindered phenol compounds, hindered
amine compounds, amino-substituted triazine compounds, phosphorus
stabilizers, and metal-containing compounds represented by the
group consisting of hydroxides, fatty acid salts, inorganic acid
salts or alkoxides of alkali metals and alkaline earth metals"
described above are sometimes written as "optional components"
hereinbelow. Such optional components may be conventional.
[0070] When carrying out the present invention, in addition to the
optional components described above, various additives such as
stabilizers, nucleating agents, release agents, fillers, pigments,
dyes, lubricants, plasticizers, antistatic agents, oil agents,
sizing agents, UV absorbers, flame retardants, flame retardant
aids, antifungal agents and antiviral agents, as well as other
resins, elastomers or the like may be added as required
appropriately to the polyacetal copolymer (X) of the invention
while still achieving the original objects. In the present
specification, the "various additives such as stabilizers,
nucleating agents, release agents, fillers, pigments, dyes,
lubricants, plasticizers, antistatic agents, oil agents, sizing
agents, UV absorbers, flame retardants, flame retardant aids,
antifungal agents and antiviral agents, as well as other resins,
elastomers or the like" are sometimes written as "additional
components" hereinbelow. Examples of the fillers include mineral
fillers and glass fibers such as glass fibers, glass flakes, glass
beads, wollastonite, mica, talc, boron nitride, calcium carbonate,
kaolin, silicon dioxide, clay, asbestos, silica, diatomaceous
earth, graphite and molybdenum disulfide, inorganic fibers such as
middle fibers, potassium titanate fibers and boron fibers, organic
fibers represented by carbon fibers and aramid fibers, potassium
titanate whisker, carbon black, and pigments.
[0071] The above-mentioned optional components and additional
components may be added to the polyacetal copolymer (X) by any
methods without limitation. For example, the polyacetal copolymer
(X), and the optional components and/or the additional components
which are added as required may be mixed and kneaded together in
any order. The mixing and kneading conditions such as temperature
and pressure may be selected appropriately from those conditions
adopted in the production of conventional polyacetal copolymers.
For example, the kneading may take place at or above the melting
point of the polyacetal copolymer, and is preferably carried out at
not less than 180.degree. C. and not more than 260.degree. C. The
apparatus for the production of the polyacetal copolymer is not
particularly limited and may be a mixer, a kneader or the like
conventionally used for the production of this type of polyacetal
copolymers. The above-mentioned optional components and additional
components may be separately mixed with, caused to penetrate,
adsorbed to or attached to the fiber containing the polyacetal
copolymer (X).
[0072] <Use Applications of Antimicrobial Fibers>
[0073] The antimicrobial fiber of the invention can be fabricated
into a nonwoven fabric, a woven fabric, a knitted fabric, a felt, a
web or the like in accordance with the use application. To take
advantage of its antimicrobial properties, a filter comprising such
a nonwoven fabric is particularly suited. Such a nonwoven fabric,
woven fabric, knitted fabric, felt and web have the same level of
antimicrobial properties as the antimicrobial fiber of the
invention, and have outstanding characteristic that antimicrobial
properties persist even after repeated washing. Further, the
inventive fibers do not suffer problems during fabrication in terms
of heat resistance or discoloration and have excellent safety as
compared to conventional antimicrobial fibers containing organic
antimicrobial agents or inorganic antimicrobial agents, thus
finding a wide range of suitable applications. In particular, the
nonwoven fabrics of the present invention may be suitably used as
filters. Such a filter has the same level of antimicrobial
properties as the antimicrobial fiber of the invention, and has
outstanding characteristic that antimicrobial properties persist
even after repeated washing. The woven fabrics, the knitted
fabrics, the felts and the webs of the present invention may be
suitably used in applications including clothing articles such as
underwear, shirts, sportswear, aprons, socks, stockings, tights,
pantyhose, Japanese tabi socks, Japanese dress goods, neckties,
handkerchiefs, scarves, headgears, gloves, masks and diapers,
bedding articles such as pillow covers, blankets, sheets and futon
or bed batting, interior articles such as curtains, carpets, mats,
rugs, wall hangings, wall upholsteries, tablecloths and moquette,
and miscellaneous goods such as towels, kitchen towels, scrub
brushes, mops and batting in stuffed toys. These clothing articles,
bedding articles, interior articles and miscellaneous goods also
have the same level of antimicrobial properties as the
antimicrobial fiber of the invention, and have outstanding
characteristic that antimicrobial properties persist even after
repeated washing.
[0074] While the antimicrobial fibers of the invention alone may be
fabricated into products such as nonwoven fabrics, woven fabrics,
knitted fabrics, felts and webs, the antimicrobial fibers of the
invention may be conjugated with synthetic fibers such as nylons,
polyesters and polyurethanes, natural fibers such as cotton and
silk, carbon fibers, glass fibers or the like so as to form twisted
yarns, covered yarns or braids which are then fabricated into
products such as nonwoven fabrics, woven fabrics, knitted fabrics,
felts and webs. Alternatively, the inventive fibers may be mixed or
mix-spun with synthetic fibers such as nylons, polyesters and
polyurethanes, natural fibers such as cotton and silk, carbon
fibers or glass fibers and may be fabricated into products such as
nonwoven fabrics, woven fabrics, knitted fabrics, felts and webs.
The inventive antimicrobial fibers or products such as woven
fabrics or knitted fabrics fabricated in accordance with use
applications may be further subjected to dyeing and various finish
treatments (such as crease resistant treatment, antifouling, flame
retarding, mothproofing, mildew proofing, deodorization,
hygroscopic treatment, waterproofing, lustering and anti-pilling)
to impart functions other than antimicrobial properties.
[0075] The antimicrobial nonwoven fabric of the invention may be
produced by any method without limitation. A known method such as a
dry process, a wet process, a spunbonding process or a meltblowing
process may be used. During the process, it is preferable that the
fibers be sufficiently bonded or entangled together to prevent
detachment of the fibers. Examples of such methods include thermal
bonding, chemical bonding, needle punching, spunlacing (waterjet
entangling), stitch bonding and steam jetting. In particular,
thermal bonding can achieve sufficient bonding and is thus
preferable.
[0076] The polyacetal copolymer (X) may be used also in a frame
member that supports the above nonwoven fabric filter. In this
manner, the product attains excellent antimicrobial properties and
recycling properties.
EXAMPLES
[0077] Hereinbelow, embodiments and advantageous effects of the
present invention will be described in detail by presenting
Examples and Comparative Examples. The scope of the invention is
not limited to such Examples.
[0078] <Polyacetal Copolymers>
[0079] The polyacetal copolymers used in Examples and Comparative
Examples are described below. The content of oxyethylene groups
(the molar amount of oxyethylene groups) in the polyacetal
copolymer (X) is a value relative to the total of the molar amount
of oxymethylene groups and the molar amount of oxyethylene
groups.
POM-1: polyacetal copolymer having a content of oxyethylene groups
of 0.4 mol % and an MVR of 8 POM-2: polyacetal copolymer having a
content of oxyethylene groups of 1.6 mol % and an MVR of 8 POM-3:
polyacetal copolymer having a content of oxyethylene groups of 3.0
mol % and an MVR of 8 POM-4: polyacetal copolymer having a content
of oxyethylene groups of 4.7 mol % and an MVR of 8 POM-5:
polyacetal copolymer having a content of oxyethylene groups of 5.7
mol % and an MVR of 8
[0080] <Other Thermoplastic Resins>
PLA (polylactic acid resin): TERRAMAC (registered trademark) TE2000
manufactured by UNITIKA LTD. was used as such. PET (polyethylene
terephthalate resin): multifilaments having a monofilament fineness
of 2 decitex were used as such.
[0081] <Measurement of MVR>
[0082] The MVR (cm.sup.3/10 min) of the polyacetal copolymers was
measured in accordance with ISO 1133.
[0083] <Measurement of Content of Oxyethylene Groups in
Polyacetal Copolymers>
[0084] The polyacetal copolymers used in Examples and Comparative
Examples were each dissolved into hexafluoroisopropanol (d2) to
give NMR measurement samples. The measurement samples were analyzed
to record NMR spectra, from which the contents of oxyethylene
groups in the polyacetal copolymers were measured.
[0085] <Measurement of Fiber Fineness>
[0086] To determine the fiber fineness [dtex (decitex)], the fiber
diameter of a monofilament was measured using an optical
microscope, and the fineness was calculated assuming that the
density was 1.40 g/cm.sup.3. The average of fifty fibers was
obtained as the fiber fineness.
[0087] <Measurement of Orientation Factor Fc (%) of
Fibers>
[0088] The measurement was performed with a wide angle X-ray
diffractometer (DP-D1 manufactured by Shimadzu Corporation), using
CuK.alpha. (a Ni filter was used) as the radiation source (output
45 KV, 40 mA). The orientation factor (fc) was determined with
respect to (100) plane observed at near 2.theta.=22.2.degree. using
the equation (1) below wherein FWHM was the full-width at
half-maximum (.degree.) of a diffraction intensity distribution
curve (an azimuthal distribution curve) obtained by scanning in the
circumferential direction.
fc (%)=((180.degree.-FWHM)/180.degree.).times.100 Equation (1)
[0089] <Fabrication of Fiber Samples>
[0090] The temperature of a cylinder and a nozzle portion was
increased to 200.degree. C. A molten resin was ejected through a
nozzle having 48 holes 0.6 mm in diameter, at a rate of 1.2 kg/h.
In the case of sheath-core conjugate fibers, the rate of ejection
from the nozzle was 0.6 kg/h for each of the resin for the core and
the resin for the sheath. During the process, the as-ejected fibers
were continuously collected at a constant take-off speed of 100
m/min, and the as-ejected fibers were subsequently guided to a
thermal drawing step in which the fibers were drawn at a roll
temperature of 120 to 140.degree. C. A fiber sample was thus
fabricated.
[0091] <Fabrication of Nonwoven Fabrics and Filters>
[0092] The drawn fibers obtained above were crimped and were cut to
a length of 51 mm. The fibers were then formed into a web with a
carding machine (manufactured by Kyowa Kizai Seisakusho) and were
entangled with a needle punching machine (manufactured by Daiwa
Kikou) into a needle punched nonwoven fabric.
[0093] <Antimicrobial test (bacteriostatic activity,
bactericidal activity, retention of bacteriostatic activity after
10 times of washing, and retention of bactericidal activity after
10 times of washing)>
[0094] In accordance with JIS L 1902 (Testing for antibacterial
activity and efficacy on textile products), the antimicrobial
properties were evaluated by a quantitative test (a bacterial
liquid absorption method). A fiber sample of standard cotton cloth,
and a fiber sample of any of Examples and Comparative Examples
(hereinafter, written as the measurement sample), each weighing 0.4
g, were placed into respective vial containers and were inoculated
with 0.2 ml of a test bacterial liquid. The bacteria were cultured
at 37.+-.2.degree. C. for 18.+-.1 hours. The bacteria were then
washed out from the samples by the addition of 20 ml of
physiological saline containing 0.2% nonionic surfactant. The
bacterial count in the spent washing liquid was measured by a pour
plate culture method (a colony method), and the bacteriostatic
activity was calculated using the equation (2) below. The larger
the value of bacteriostatic activity, the more excellent the
antimicrobial properties. Incidentally, 2.2 or higher
bacteriostatic activity on Staphylococcus aureus corresponds to the
SEK mark (blue: antimicrobial and deodorant finished) certified by
Japan Textile Evaluation Technology Council. Further, the
bactericidal activity was calculated using the equation (3) below.
The larger the value of bactericidal activity, the more excellent
the antimicrobial properties. More than 0 activity means that
bacteria are reduced in number between before and after the
antimicrobial test.
Bacteriostatic activity={log(viable bacterial count after culture
in standard cotton cloth)-log(viable bacterial count immediately
after inoculation on standard cotton cloth)}-{log(viable bacterial
count after culture in measurement sample)-log(viable bacterial
count immediately after inoculation on measurement sample)}
Equation (2)
Bactericidal activity=log(viable bacterial count immediately after
inoculation on standard cotton cloth)-log(viable bacterial count
after culture in measurement sample) Equation (3)
[0095] The retentions of bacteriostatic activity and bactericidal
activity after 10 times of washing were determined in the following
manner. The washing method was in conformity with JIS L 0217, No.
103, and the detergent was JAFET standard detergent. After being
washed repeatedly 10 times, the samples were subjected to the above
antimicrobial testing, and the retention [unit: %] of
bacteriostatic activity after 10 times of washing was calculated
using the equation (4) below. Further, the retention [unit: %] of
bactericidal activity after 10 times of washing was calculated
using the equation (5) below. In each case, the closer the value to
100%, the higher the antimicrobial properties.
Retention of bacteriostatic activity (%)=(bacteriostatic activity
after 10 times of washing/bacteriostatic activity before washing
treatment).times.100 Equation (4)
Retention of bactericidal activity (%)=(bactericidal activity after
10 times of washing/bactericidal activity before washing
treatment).times.100 Equation (5)
[0096] The bacteriostatic activity, the bactericidal activity, and
the retentions of bacteriostatic activity and bactericidal activity
after 10 times of washing were measured on Staphylococcus aureus
and Moraxella osloensis.
EXAMPLES AND COMPARATIVE EXAMPLES
[0097] Table 1 shows Examples of monolayer fibers of a polyacetal
copolymer having an oxyethylene content in the prescribed range,
multilayer fibers of polyacetal copolymers having an oxyethylene
content in the prescribed range, and multilayer fibers of PLA and a
polyacetal copolymer having an oxyethylene content in the
prescribed range, and Comparative Examples of polyester fibers and
monolayer fibers of a polyacetal copolymer having an oxyethylene
content exceeding the prescribed range.
[0098] The table describes the oxyethylene content in the
polyacetal copolymer, the monofilament fineness, the orientation
factor, the viable bacterial count (unit: colonies) after culture
in the aforementioned antimicrobial test, the increase ratio before
and after the antimicrobial test, the bacteriostatic activity, the
retention of bacteriostatic activity after 10 times of washing, the
bactericidal activity, and the retention of bactericidal activity
after 10 times of washing obtained in each of Examples and
Comparative Examples.
[0099] From Examples 1 to 6 and Comparative Examples 1 and 2, it
has been shown that excellent bacteriostatic activity, bactericidal
activity and retention of bactericidal activity after washing are
attained when the oxyethylene content in the polyacetal copolymer
is 0.2 to 5 mol %. Examples 4 to 6 show that the bacteriostatic
activity, the bactericidal activity and the retention of
bactericidal activity after washing are further enhanced when the
polyacetal copolymer in the fibers has a high orientation
factor.
TABLE-US-00001 TABLE 1 Ex. 1 Ex. 2 Ex. 3 Ex. 4 Ex. 5 Raw materials
of fibers POM-1 POM-2 POM-3 POM-4 POM-4 Oxyethylene content in
polyacetal copolymer [mol %] 0.4 1.6 3.0 4.7 4.7 Melting point of
polyacetal copolymer [.degree. C.] 170 166 160 155 155 Draw
temperature [.degree. C.] 140 135 130 125 125 Draw ratio 5.2 5.2
5.2 5.2 8.3 Monofilament fineness [dtex] 8 8 8 8 5 Orientation
factor of fibers [%] 87 84 84 82 93 Addition of antimicrobial agent
No No No No No Antimicrobial test Staphylococcus Viable bacterial
count after culture [colonies] 1.00.E+04 1.58.E+04 3.16.E+04
3.98.E+04 2.51.E+04 aureus Increase ratio(*3) before and after
antimicrobial test 0.5 0.8 1.6 2.0 1.3 Bacteriostatic activity(*1)
2.9 (2.9) 2.7 2.4 2.3 2.5 Retention of bacteriostatic activity
after 10 times 100 (100) 100 100 99 100 of washing [%](*1)
Antimicrobial and deodorant finished certification(*2)
.largecircle. .largecircle. .largecircle. .largecircle.
.largecircle. Bactericidal activity(*1) 0.3 (0.3) 0.1 -0.2 -0.3
-0.1 Retention of bactericidal activity after 10 times 100 (100)
100 100 97 100 of washing(*1) Moraxella Viable bacterial count
after culture [colonies] 1.00.E+05 1.26.E+05 1.58.E+05 2.00.E+05
2.00.E+05 osloensis Increase ratio(*3) before and after
antimicrobial test 5.0 6.3 7.9 10.0 10.0 Bacteriostatic
activity(*1) 2.3 (2.3) 2.2 2.1 2.0 2.0 Retention of bacteriostatic
activity after 10 times 100 (100) 100 100 99 100 of washing [%](*1)
Bactericidal activity(*1) -0.7 (-0.7) -0.8 -0.9 -1.0 -1.0 Retention
of bactericidal activity after 10 times 100 (100) 100 100 91 97 of
washing(*1) Comp. Comp. Ex. 6 Ex. 7 Ex. 8 Ex. 1 Ex. 2 Raw materials
of fibers POM-4 POM-1 PLA PET POM-5 (core)/ (core)/ POM-4 POM-4
(sheath) (sheath) Oxyethylene content in polyacetal copolymer [mol
%] 4.7 0.4/4.7 --/4.7 -- 5.7 Melting point of polyacetal copolymer
[.degree. C.] 155 170/155 --/155 -- 147 Draw temperature [.degree.
C.] 125 130 130 -- 125 Draw ratio -- 5.2 5.2 -- -- Monofilament
fineness [dtex] 42 8 8 2 42 Orientation factor of fibers [%] 63 85
84 -- 72 Addition of antimicrobial agent No No No No No
Antimicrobial test Staphylococcus Viable bacterial count after
culture [colonies] 5.01.E+04 3.16.E+04 3.16.E+04 -- 7.94.E+04
aureus Increase ratio(*3) before and after antimicrobial test 2.5
1.6 1.6 -- 4.0 Bacteriostatic activity(*1) 2.2 2.4 2.4 0.6 2.0
Retention of bacteriostatic activity after 10 times 92 99 98 93 82
of washing [%](*1) Antimicrobial and deodorant finished
certification(*2) .largecircle. .largecircle. .largecircle. X X
Bactericidal activity(*1) -0.4 -0.2 -0.2 -- -0.6 Retention of
bactericidal activity after 10 times 91 100 100 -- 89 of
washing(*1) Moraxella Viable bacterial count after culture
[colonies] 3.16.E+05 2.00.E+05 2.00.E+05 -- 6.31.E+05 osloensis
Increase ratio(*3) before and after antimicrobial test 15.8 10.0
10.0 -- 31.6 Bacteriostatic activity(*1) 1.8 2.0 2.0 0.7 1.5
Retention of bacteriostatic activity after 10 times 89 99 98 91 83
of washing [%](*1) Bactericidal activity(*1) -1.2 -1.0 -1.0 -- -1.5
Retention of bactericidal activity after 10 times 88 98 97 -- 81 of
washing(*1) *(1)The numbers in parenthesis indicate results of
evaluation as nonwoven fabrics. The numbers without parenthesis
indicate results of fiber samples simply bundled. *(2).largecircle.
and X indicate that the product corresponded and did not
correspond, respectively, to the SEK mark (blue: antimicrobial and
deodorant finished) certified by Japan Textile Evaluation
Technology Council. *(3)Increase ratio before and after
antimicrobial test = viable bacterial count after culture/viable
bacterial count immediately after inoculation Bacteriostatic
activity = {log(viable bacterial count after culture in standard
cotton cloth) - log(viable bacterial count immediately after
inoculation on standard cotton cloth)} - {log(viable bacterial
count after culture in measurement sample) - log(viable bacterial
count immediately after inoculation on measurement sample)}
Bactericidal activity = log(viable bacterial count immediately
after inoculation on standard cotton cloth) - log(viable bacterial
count after culture in measurement sample)
* * * * *