U.S. patent application number 14/064538 was filed with the patent office on 2014-05-01 for glove.
This patent application is currently assigned to SHOWA GLOVE CO.. The applicant listed for this patent is SHOWA GLOVE CO.. Invention is credited to Hidetoshi KISHIHARA, Kodai KOZUKI, Ryo SAITO.
Application Number | 20140115751 14/064538 |
Document ID | / |
Family ID | 49513812 |
Filed Date | 2014-05-01 |
United States Patent
Application |
20140115751 |
Kind Code |
A1 |
SAITO; Ryo ; et al. |
May 1, 2014 |
GLOVE
Abstract
Disclosed is a glove having a rubber or resin coated on the
surface of a fiber-made glove, wherein a stretchable yarn is
knitted at least into the wrist area of the fiber-made glove, the
stretchable yarn having a rubber or resin coated thereon, and
wherein a difference in level occurring at the boundary portion
between the areas where the stretchable yarn is knitted and where
it is not knitted is 210 .mu.m or less. The glove of the present
invention is a chemical-resistant, support-type glove in which no
cracks or pin holes are formed at the boundary portion between the
areas where the stretchable yarn is knitted and where it is not
knitted, and which is superior in chemical permeation-resistance
property and has a high degree of safety.
Inventors: |
SAITO; Ryo; (Himeji-shi,
JP) ; KOZUKI; Kodai; (Himeji-shi, JP) ;
KISHIHARA; Hidetoshi; (Himeji-shi, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SHOWA GLOVE CO. |
Himeji-shi |
|
JP |
|
|
Assignee: |
SHOWA GLOVE CO.
Himeji-shi
JP
|
Family ID: |
49513812 |
Appl. No.: |
14/064538 |
Filed: |
October 28, 2013 |
Current U.S.
Class: |
2/168 |
Current CPC
Class: |
A41D 19/0065 20130101;
A41D 19/0082 20130101 |
Class at
Publication: |
2/168 |
International
Class: |
A41D 19/00 20060101
A41D019/00 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 31, 2012 |
JP |
2012-240081 |
Claims
1. A glove having a rubber or resin coated on the surface of a
fiber-made glove, wherein a stretchable yarn is knitted at least
into a wrist area of the fiber-made glove, the stretchable yarn
having a rubber or resin coated thereon, and wherein a difference
in level occurring at the boundary portion between the areas where
the stretchable yarn is knitted and where it is not knitted is 210
.mu.m or less.
2. The glove according to claim 1, wherein the difference in level
occurring at the boundary portion between the areas where the
stretchable yarn is knitted and where it is not knitted is 50 .mu.m
or less.
3. The glove according to claim 1, wherein the glove has a sulfuric
acid permeation time of 20 minutes or more in a test for sulfuric
acid permeation in accordance with the method specified in European
Standard EN 374-3.
4. The glove according to claim 1, wherein the glove has a sulfuric
acid permeation time of 30 minutes or more in a test for sulfuric
acid permeation in accordance with the method specified in European
Standard EN 374-3.
5. The glove according to claim 1, wherein a coating layer of a
synthetic rubber or resin is formed on the surface of the
fiber-made glove by coagulation method by use of a coagulant, using
a rubber or resin latex compound comprising 1.0 part by weight or
more of a crack inhibitor per 100 parts by weight of a rubber or
resin solid content.
6. The glove according to claim 5, wherein the crack inhibitor is
at least one selected from the group consisting of titanium
dioxide, silicon dioxide and zirconium dioxide.
7. The glove according to claim 5, wherein the coagulant is an
organic acid-based coagulant.
8. The glove according to claim 7, wherein the organic acid-based
coagulant comprises at least one coagulant selected form the group
consisting of acetic acid, formic acid, propionic acid, citric
acid, and oxalic acid and at least one solvent selected from the
group consisting of water, methanol and ethanol.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a chemical-resistant glove,
and more specifically, relates to a chemical-resistant,
support-type glove in which no cracks or pin holes are formed at
the boundary portion between the areas where a stretchable yarn is
used and where it is not used, and which is superior in chemical
permeation-resistance property and has a high degree of safety.
[0003] 2. Description of the Prior Art
[0004] There have been conventionally used, as working gloves,
so-called support-type gloves in which polyvinyl chloride,
polyurethane, a natural rubber, a synthetic rubber (NBR-, SBR-,
chloroprene-, or silicone-based rubber), or the like have been
coated on a fiber-made glove (for example, JP-A-2012-77416).
[0005] In manufacturing these working gloves, a fiber-made glove
cannot sufficiently fit to a dipping hand-mold in a step in which
the fiber-made glove is put on the dipping hand-mold, and wrinkles
may consequently be formed on the fiber-made glove. These wrinkles
cause the formation of cracks, pin holes, and the like on a coating
formed when a rubber or resin is coated onto the fiber-made glove.
Accordingly, in order to allow a fiber-made glove to sufficiently
fit to a dipping hand-mold, and to improve the fitting property to
the hand of a user of the finished glove and the anti-slip property
of the finished glove, it has been conventionally known that a
stretchable yarn (rubber thread) is knitted into a fiber-made glove
(for example, Japanese Patent Nos. 3760441 and 2925543, and
JP-A-2007-9346).
[0006] In addition, there is known a method for producing a glove
in which after a rubber is coated on a fiber-made glove using a
dipping hand-mold, the glove is transferred from the dipping
hand-mold onto a forming hand-mold, followed by heat curing, in
order to form the glove into a glove having a sharper
three-dimensional shape (for example, JP-A-2005-320652). If a
support glove is produced by the method using a fiber-made glove
not including a stretchable yarn, then the fiber-made glove does
not fit to a forming hand-mold, and as a result, the support glove
does not fit to the hand of its user. Also in such a case,
therefore, a fiber-made glove into which a stretchable yarn is
knitted is used.
SUMMARY OF THE INVENTION
[0007] In the case where a rubber or resin is coated on a
conventional fiber-made glove into which a stretchable yarn is
knitted, however, cracks or pin holes are easily formed on the
coating at the boundary portion between the areas where the
stretchable yarn is knitted and where it is not knitted. When such
cracks, pin holes, and the like are formed, water or chemicals
penetrate into the inside of the glove through the cracks or the
like during operation, thereby causing safety impairment and thus
inviting a danger.
[0008] To solve the problems described above, the present inventors
have made extensive studies, and as a result, have found out that
the difference in level occurs at the boundary portion between the
areas where a stretchable yarn is knitted and where it is not
knitted, thereby causing cracks and others at the boundary portion.
Based on this finding, the present inventors have completed the
present invention.
[0009] That is, the present invention aims to solve problems
associated with conventional chemical-resistant gloves, thereby to
provide a chemical-resistant, support-type glove in which cracks or
pin holes are difficult to be formed at the boundary portion
between the areas where a stretchable yarn is knitted and where it
is not knitted and which is superior in chemical
permeation-resistance property and has a high degree of safety.
[0010] An aspect of the present invention relates to a glove having
a rubber or resin coated on the surface of a fiber-made glove,
wherein a stretchable yarn is knitted at least into the wrist area
of the fiber-made glove, the stretchable yarn having a rubber or
resin coated thereon, and wherein a difference in level occurring
at the boundary portion between the areas where the stretchable
yarn is knitted and where it is not knitted is 210 .mu.m or
less.
[0011] Another aspect of the present invention relates to the
glove, wherein a difference in level occurring at the boundary
portion between the areas where the stretchable yarn is knitted and
where it is not knitted is 50 .mu.m or less.
[0012] Another aspect of the present invention relates to the
glove, wherein the glove has a sulfuric acid permeation time of 20
minutes or more in a test for sulfuric acid permeation in
accordance with the method specified in European Standard EN
374-3.
[0013] Another aspect of the present invention relates to the
glove, wherein the glove has a sulfuric acid permeation time of 30
minutes or more in a test for sulfuric acid permeation in
accordance with the method specified in European Standard EN
374-3.
[0014] Another aspect of the present invention relates to the
glove, wherein a coating layer of a synthetic rubber or resin is
formed on the surface of the fiber-made glove by an acid
coagulation method using a rubber or resin latex compound
comprising 1.0 part by weight or more of a crack inhibitor per 100
parts by weight of a rubber or resin solid content and using an
organic acid-based coagulant as a coagulant.
[0015] Another aspect of the present invention relates to the
glove, wherein the crack inhibitor is at least one selected from
the group consisting of titanium dioxide, silicon dioxide and
zirconium dioxide.
[0016] Another aspect of the present invention relates to the
glove, wherein the organic acid-based coagulant comprises at least
one coagulant selected from the group consisting of acetic acid,
formic acid, propionic acid, citric acid and oxalic acid, and at
least one solvent selected from the group consisting of water,
methanol and ethanol.
[0017] According to the present invention, a difference in level
occurring at the boundary portion between the areas where the
stretchable yarn is knitted and where it is not knitted is 210
.mu.m or less, preferably 50 .mu.m or less, so that a
chemical-resistant, support-type glove can be provided in which
cracks or pin holes are not formed at the boundary portion and
which is superior in chemical permeation-resistance property and
has a high degree of safety.
DETAILED DESCRIPTION OF THE INVENTION
[0018] The glove of the present invention is a glove having a
rubber or resin coated on the surface of a fiber-made glove,
wherein a stretchable yarn is knitted at least into the wrist area
of the fiber-made glove, the stretchable yarn having a rubber or
resin coated thereon, and wherein a difference in level occurring
at the boundary portion between the areas where the stretchable
yarn is knitted and where it is not knitted is 210 .mu.m or
less.
[0019] For the fiber-made glove in the present invention, gloves
made of various fibers can be applied, and gloves made by knitting,
in a seamless manner, known filament yarns or spun yarns alone or
in combination, for example, yarns of cotton, polyamide (nylon),
polyester, polyurethane, high-strength stretched polyethylene such
as Dyneema (registered trademark), and aramid such as Kevlar
(registered trademark); gloves made by sewing knitted fabrics,
woven fabrics, and nonwoven fabrics; and the like can be used.
[0020] In the fiber-made glove for use in the present invention, a
stretchable yarn is knitted at least into the wrist area.
[0021] In the present invention, the stretchable yarn refers to a
yarn having rubber elasticity, called a rubber thread, that is, a
yarn in which a yarn of a non-elastic fiber is wound around an
elastic fiber such as spandex, such that it has rubber elasticity
and can be used in common knitting machines. In the present
invention, any stretchable yarn can be used which has rubber
elasticity and can be knitted into the fiber-made glove. Such a
stretchable yarn which is commercial available includes, for
example, LYCRA (registered trademark) (Toray Opelontex Co.,
Ltd.).
[0022] In the present invention, a method for weaving a stretchable
yarn into the fiber-made glove is not limited in particular, and
examples thereof can include a method in which in a knitting
procedure concurrently using two yarns as in knitting with some
yarns together or plating knitting, one of the two yarns is changed
to a stretchable yarn in a predetermined part; and a method in
which in a usual knitting procedure as in plain stitching in which
knitting is performed using one yarn, a stretchable yarn is added
in and knitted into a predetermined part.
[0023] In the present invention, a rubber or resin is coated on the
surface of the fiber-made glove. The rubber or resin is usually
coated on the whole of the glove; however, any glove in which at
least the boundary portion between the areas where a stretchable
yarn is knitted and where it is not knitted is coated with the
rubber or resin is included in the present invention.
[0024] Examples of the rubber for use in the present invention can
include a natural rubber (NR); a diene-based rubber such as a
nitrile-butadiene rubber (NBR), a styrene-butadiene rubber (SBR),
and a butadiene rubber; an isoprene rubber; and a butyl rubber.
Among them, a nitrile-butadiene rubber is particularly preferred
from the viewpoints of economic efficiency, versatility, no
proteins which are likely to cause allergy, and the like. These
rubbers are generally used in an aqueous dispersion latex, though
they can also be used in a solvent solution or a solvent
dispersion.
[0025] Examples of the resin for use in the present invention can
include polyvinyl chloride, polyurethane, an ethylene-vinyl alcohol
copolymer, polyvinyl acetate, and modifications thereof. These are
used alone or in combination of two or more as necessary.
[0026] A rubber or resin latex can have one or more of a metal
oxide, a vulcanization accelerator, sulfur, a surfactant, an
antioxidant, a pH adjusting agent, a plasticizer, a filler, and the
like compounded therein.
[0027] A specific method for coating the rubber or resin on the
fiber-made glove is not limited in particular, and examples thereof
can include a method in which the fiber-made glove is put on a
hand-mold, then dipped into a solution of a coagulant, pulled out
of the solution, dried, thereafter, dipped into a rubber or resin
latex, pulled out of the latex after a given period of time, and
dried. The hand-mold for use in this method is not limited in
particular, and any hand-mold made of metal, ceramic, wood,
plastic, or the like can be used.
[0028] The coagulant for use in the present invention may be one
usually used. Specifically, an acid such as formic acid, acetic
acid, propionic acid, citric acid, oxalic acid or sulfuric acid; or
a salt such as sodium chloride, aluminum sulfate, or calcium
nitrate can be used. Among them, an inorganic salt of a divalent
alkaline earth metal, which is represented by calcium nitrate, is
preferable in terms of its high capability of coagulation. A
solvent in which these coagulants can be dissolved is not limited
in particular. While water, methanol, ethanol, or the like is
usually used, methanol is preferable in that it is volatile and is
easy to be dried out.
[0029] In the present invention, it is preferable that a crack
inhibitor is added, in order to enhance the chemical
resistance.
[0030] The crack inhibitor for use in the present invention is a
metallic oxide containing a tetra-valent element, and preferable
examples thereof include titanium dioxide (TiO.sub.2), silicon
dioxide (SiO.sub.2) and zirconium dioxide (ZrO.sub.2), which can be
used alone or in combination.
[0031] Titanium dioxide and silicon dioxide are known as fillers.
For example, JP-A-2011-32590 and JP-A-2011-231448 also describe
that these can be compounded in a latex. However, titanium dioxide
is used for the purposes of masking and of preventing coagulation
by crushing it into smaller pieces than other fillers, and silicon
dioxide is used for the purposes of preventing sagging, surface
modification and of improving the anti-slip property. These
purposes are quite different from the purpose of improving the
chemical resistance in the present invention.
[0032] The crack inhibitor is used in an amount of 1.0 part by
weight or more per 100 parts by weight of the synthetic rubber or
resin solid content. When the crack inhibitor is used in an amount
of less than 1.0 part by weight, it does not exhibit a satisfactory
crack-inhibiting effect. The upper limit for the crack inhibitor is
not defined in particular; however, it is preferably approximately
10 parts by weight or less from the viewpoint that a satisfactory
crack-inhibiting effect is achieved, more preferably 5 parts by
weight or less from the viewpoint of the stability of a compound,
and preferably 2 parts by weight or less from the viewpoint of
cost.
[0033] The particle size of the crack inhibitor is not limited in
particular, and is preferably 20 .mu.M or less and more preferably
10 .mu.m or less from the viewpoint that no aggregates are formed
in a rubber compounding system and the like. Regarding the type and
shape of the crack inhibitor, when the crack inhibitor is titanium
dioxide, it is preferably one having a rutile-type crystal
structure, and when the crack inhibitor is silicon dioxide, it is
preferably one produced by a wet method, among those which are
amorphous silica not having a particular crystal structure.
[0034] When the crack inhibitor is added in the present invention,
the coagulant is preferably an organic acid, so that a superior
crack-inhibiting effect is achieved by a synergetic effect of the
crack inhibitor and the coagulant. Examples of such an organic acid
can include acetic acid, formic acid, propionic acid, citric acid
and oxalic acid. As a solvent in which these organic acids can be
dissolved, water, methanol, ethanol or the like is usually used,
and methanol is preferable in that it is volatile and is easy to be
dried out.
[0035] The ratio of the organic acid to the solvent is preferably 2
to 6 parts by weight of the organic acid per 100 parts by weight of
the solvent. When the organic acid is used in an amount of less
than 2 parts by weight, there is a tendency that groove-like cracks
are formed. When the organic acid is used in an amount of more than
6 parts by weight, on the other hand, there is a tendency that the
coating easily peels from the fiber-made glove.
[0036] In the case where the solvent is water, the pH of the
aqueous coagulant solution is preferably from 2 to 2.7, and more
preferably from 2.2 to 2.6. At a pH of less than 2, there is a
tendency that peeling is caused between the fiber-made glove and
the coating layer. At a pH of more than 2.6, on the other hand,
there is a tendency that sufficient coagulation is not
achieved.
[0037] In the case where the solvent is not water, it is preferable
that when the solvent is replaced with the same weight of water,
the pH is within the above-described range.
[0038] After the rubber or resin is coated on the fiber-made glove,
the glove is subjected to heat curing. Conditions for the heat
curing are those usually used in the art. Specifically, heat curing
is carried out at 100 to 150.degree. C. for 0.15 to 1 hour,
preferably at 120 to 140.degree. C. for 0.25 to 0.5 hours. However,
when the coated glove is subjected to heating immediately under the
above conditions, water contained in the glove rapidly vaporizes
within the coating, which adversely affects the quality of the
glove and may give rise to a so-called blistering phenomenon.
Therefore, it is preferable that before the heat curing at high
temperatures, heating is performed at 60 to 90.degree. C. for 0.5
to 1 hour, preferably at 60 to 80.degree. C. for 0.5 to 0.75 hours,
so as to reduce the water content in the coating.
[0039] After the heat curing, the glove is removed from the
hand-mold and then optionally subjected to washing with water and
drying, to obtain a glove of the present invention.
[0040] The glove of the present invention is characterized in that
the difference in level occurring at the boundary portion between
the areas where a stretchable yarn is knitted and where it is not
knitted is 210 .mu.m or less, and preferably 50 .mu.m or less. The
smaller the difference in level occurring at the boundary portion,
the more desirable it is. For example, the area of the fiber-made
glove, where a stretchable yarn is to be knitted, is allowed to
have a thickness reduced in advance by a degree corresponding to
the thickness of the stretchable yarn to be knitted, so that the
difference in level can be 0 .mu.m.
[0041] A method for reducing to a given value or less, the
difference in level occurring at the boundary portion is not
limited in particular, and examples thereof include a method in
which the stretchable yarn is selected so as to reduce the
difference in level between the areas where the stretchable yarn is
knitted and where it is not knitted.
[0042] Specifically, in the case of a method in which in a knitting
procedure concurrently using two yarns as in knitting with some
yarns together or plating knitting, one of the two yarns is changed
to a stretchable yarn in a predetermined part, it is preferable
that the weights per unit length (hereinafter referred to as
"denier number") of the knitting yarn before changed and of the
stretchable yarn are as close as possible. For example, the denier
number of the stretchable yarn is preferably 30 to 300%, and more
preferably 50 to 250%, of that of the knitting yarn before
changed.
[0043] In the case of a method in which in a usual knitting
procedure in which knitting is performed using one yarn, a
stretchable yarn is added and only a predetermined part is knitted
using two yarns, on the other hand, the finer the stretchable yarn
to be used, the more desirable it is. For example, the stretchable
yarn preferably has a denier number of 140 deniers or less, more
preferably 90 deniers or less.
[0044] A method for determining, in the glove of the present
invention, the difference in level occurring at the boundary
portion between the areas where a stretchable yarn is knitted and
where it is not knitted is carried out as described below.
[0045] The boundary portion is cut in the direction perpendicular
to that of knitting of the stretchable yarn, and its cross-section
is subjected to observation by a microscope (Model VHX-900,
manufactured by KEYENCE CORPORATION) with the rubber or resin
coating in an upward direction and the portion of the fiber-made
glove in a downward direction. After the observation, a straight
line A is drawn horizontally passing the outermost of the coating
of the rubber or resin with which the area comprising no
stretchable yarn is coated, and a straight line B is drawn in
parallel to the line A, passing the outermost of the coating of the
rubber or resin with which the area comprising a stretchable yarn
is coated. The distance between these lines A and B is determined
and defined as the difference in level. When the measurement is
carried out for a plurality of boundary portions, the maximum value
of all measurements is defined as the difference in level.
[0046] The present invention will be described in more detail below
with reference to Examples, which are not intended to limit the
present invention thereto in any way.
Example 1
[0047] Plating knitting is carried out using two polyester
twin-folded yarns of 75 deniers (82.5 dtex) as ground knitting
yarns and one polyester twin-folded yarn of 75 deniers (82.5 dtex)
as an appending yarn. In the wrist area, the appending yarn was
changed to a stretchable yarn having one wooly nylon single yarn of
70 deniers (77 dtex) wound around a spandex of 20 deniers (22
dtex), which in turn was subjected to knitting, to produce a
fiber-made glove comprising an area where the stretchable yarn was
knitted and a flat-knit area where it was not knitted. The plating
knitting was carried out such that the ground knitting yarns were
on the face side and the appending yarn was on the wrong side.
[0048] The fiber-made glove was put on a dipping hand-mold. Then,
the dipping hand-mold was dipped in a bath containing a coagulant
including 5 parts by weight of acetic acid and 100 parts by weight
of methanol, and pulled out of the bath after 5 seconds.
[0049] The glove dipped into the coagulant was dried at 30.degree.
C. for 45 seconds. Then, the entire of the fiber-made glove was
dipped in a bath containing an NBR latex compound shown in Table 1,
pulled out of the bath, and dried at 70.degree. C. for 30 minutes.
After that, the glove dried was removed from the dipping hand-mold
and subjected to leaching in warm water at 30.degree. C. for 1
hour.
[0050] After the leaching, water was removed from the glove. Then,
the glove was put on a setting hand-mold (hand-mold with a natural
shape of the human's hand) and subjected to heat curing. The heat
curing was carried out first by heat drying at 70.degree. C. for 60
minutes and then by heating at 120.degree. C. for 20 minutes.
[0051] After the heat curing, the glove was removed from the
setting hand-mold, to obtain a glove of the present invention.
[0052] It was found that for the resulting glove, the difference in
level occurring at the boundary portion between the areas where the
stretchable yarn was knitted and where it was not knitted was 32.4
.mu.m.
TABLE-US-00001 TABLE 1 Added parts Trade name Name of Material
Maker (by wt.) Nipol (Registered NBR latex ZEON CORPORATION 100
trademark) LX550 KOH pH adjusting agent KANTO CHEMICAL CO., INC.
0.5 S Vulcanizing agent KANTO CHEMICAL CO., INC. 1.5 ZnO
Crosslinking agent KANTO CHEMICAL CO., INC. 2 BZ Vulcanization
accelerator OUCHI SHINKO CHEMICAL 0.5 INDUSTRIAL CO., LTD BKF
Antioxidant Lanxess 0.5 TiO2 Metallic oxide Ishihara Sangyo Kaisha,
Ltd. 2 A-7075 Thickening agent Toagosei Co., Ltd. 0.2 Water 35
Example 2
[0053] A glove of the present invention was produced in the same
way as in Example 1, except that as the fiber-made glove, a glove
was used which was knitted by flat knitting using two polyester
twin-folded yarns of 75 deniers (82.5 dtex) and in which only the
wrist area was knitted using three yarns including a stretchable
yarn of a covering yarn having one wooly nylon single yarn of 70
deniers (77 dtex) wound around a spandex of 20 deniers (22
dtex).
[0054] It was found that for the resulting glove, the difference in
level occurring at the boundary portion between the areas where the
stretchable yarn was knitted and where it was not knitted was 40.7
.mu.m.
Example 3
[0055] A glove of the present invention was produced in the same
way as in Example 2, except that as the stretchable yarn, a
stretchable yarn of a covering yarn having one wooly nylon single
yarn of 70 deniers (77 dtex) wound around a spandex of 70 deniers
(77 dtex) was used.
[0056] It was found that for the resulting glove, the difference in
level occurring at the boundary portion between the areas where the
stretchable yarn was knitted and where it was not knitted was 200.5
.mu.m.
Example 4
[0057] The procedure was carried out in the same way as in Example
1, before the glove was pulled out of the bath containing the NBR
latex formulation solution. After that, the glove was dried at
25.degree. C. for 7 minutes and then at 75.degree. C. for 5
minutes. Subsequently, the glove dried was subjected to leaching in
warm water at 50.degree. C. for 2 minutes, and then pulled out of
warm water and dried until water droplets on the surface
disappeared, thereby forming a first layer of coating.
[0058] The glove having the first coating layer formed thereon was
subjected to dipping for 5 seconds into the same latex formulation
solution as shown in Table 1, except that the NBR latex was changed
to Lx-551 and the amount of the thickening agent A-7075 was changed
to 0.3 parts by weight. Then, the glove was dried, subjected to
leaching, and dried again in the same way as for the first layer,
thereby forming a second layer of coating.
[0059] Subsequently, the glove having the second coating layer
formed thereon was subjected to dipping for about 5 seconds in a
bath containing the same latex formulation solution as for the
second layer, pulled out of the bath, and then dried until water
droplets on the surface disappeared, thereby forming a third layer
of coating.
[0060] Then, the glove was dried at 70.degree. C. for 40 minutes.
The glove was removed from the hand-mold and dipped into water at
25.degree. C. for leaching for 1 hour.
[0061] After the leaching, water was removed from the glove. Then,
the glove was put on a setting hand-mold and subjected to heat
curing. The heat curing was carried out first by heating at
70.degree. C. for 60 minutes and then by heating at 130.degree. C.
for 20 minutes. After the heat curing, the glove was removed from
the setting hand-mold, to obtain a glove of the present
invention.
[0062] It was found that for the resulting glove, the difference in
level occurring at the boundary portion between the areas where the
stretchable yarn was knitted and where it was not knitted was 15.1
.mu.m.
Example 5
[0063] A glove of the present invention was produced in the same
way as in Example 1, except that the crack inhibitor TiO.sub.2 was
changed to SiO.sub.2 was used.
[0064] It was found that for the resulting glove, the difference in
level occurring at the boundary portion between the areas where the
stretchable yarn was knitted and where it was not knitted was 31.9
.mu.m.
Example 6
[0065] A glove of the present invention was produced in the same
way as in Example 1, except that the crack inhibitor TiO.sub.2 was
not used.
[0066] It was found that for the resulting glove, the difference in
level occurring at the boundary portion between the areas where the
stretchable yarn was knitted and where it was not knitted was 32.1
.mu.m.
Example 7
[0067] A glove of the present invention was produced in the same
way as in Example 1, except that 5 parts by weight of acetic acid
was changed to 5 parts by weight of citric acid.
[0068] It was found that for the resulting glove, the difference in
level occurring at the boundary portion between the areas where the
stretchable yarn was knitted and where it was not knitted was 33.5
.mu.m.
Example 8
[0069] A glove of the present invention was produced in the same
way as in Example 1, except that 5 parts by weight of acetic acid
was changed to 5 parts by weight of calcium nitrate.
[0070] It was found that for the resulting glove, the difference in
level occurring at the boundary portion between the areas where the
stretchable yarn was knitted and where it was not knitted was 31.5
.mu.m.
Comparative Example 1
[0071] A glove was produced in the same way as in Example 2, except
that as the stretchable yarn, used was a stretchable yarn of a
covering yarn having one wooly nylon twin-folded yarn of 70 deniers
(77 dtex) wound around a spandex of 70 deniers (77 dtex).
[0072] It was found that for the resulting glove, the difference in
level occurring at the boundary portion between the areas where the
stretchable yarn was knitted and where it was not knitted was 222.4
.mu.m.
Comparative Example 2
[0073] A glove was produced in the same way as in Example 2, except
that as the stretchable yarn, used was a stretchable yarn of a
covering yarn having two wooly nylon twin-folded yarns of 70
deniers (82.5 dtex) wound around a spandex of 280 deniers (308
dtex).
[0074] It was found that for the resulting glove, the difference in
level occurring at the boundary portion between the areas where the
stretchable yarn was knitted and where it was not knitted was 643
.mu.m.
[0075] The gloves obtained in Examples 1 to 8 and Comparative
Examples 1 to 2 were subjected to visual observation for the
presence or absence of the occurrence of cracks or pin holes at the
boundary portion, and in addition, to an air leakage test (in
accordance with EN 374-2).
[0076] Further, in order to evaluate the chemical resistance of the
coatings, a test for sulfuric acid permeation was carried out based
on the specification of European Standard EN 374-3 "gloves for
chemical protection." The testing was carried out by holding the
outer surface side of the coating in contact with sulfuric acid
(having a concentration of 96%) and passing, on the other side, 0.1
M KCl as a carrier to measure the pH of the carrier.
[0077] Specifically, the pH value measured was used to calculate
the concentration of hydrogen ion, which in turn was used to
calculate the concentration of sulfuric acid. The concentration of
sulfuric acid thus obtained was used to calculate the amount of
permeation of sulfuric acid per minute, based on the amount,
calculating the time (in minutes) to take until the amount of
permeation of sulfuric acid per minute exceeded 1 .mu.g/cm.sup.2,
which was defined as the measurement value. The results are shown
in Table 2.
[0078] As apparent from Table 2, the gloves of Examples 1 to 8
having a difference in level at the boundary portion of 210 .mu.m
or less were ascertained to have no detectable cracks or pin holes,
whereas the gloves of Comparative Examples 1 and 2 having a
difference in level at the boundary portion of more than 210 .mu.m
were ascertained to have cracks or pin holes. Additionally, when
the gloves of Examples 1 and 2 were compared with that of Example
3, the gloves of Examples 1 and 2 were found to be superior to that
of Example 3 in uniform adhesion of the rubber latex.
[0079] Further, from the comparison of the gloves of Examples 1, 5
and the glove of Example 6, the gloves of Examples 1, 5 using the
crack inhibitor is superior in chemical resistance to that of
Example 6 not using the crack inhibitor.
[0080] Furthermore, from the comparison of the gloves of Examples
1, 7 and the glove of Example 8, when the crack inhibitor is used,
the gloves of Example 1, 7 using the organic acid as the coagulant
is superior in chemical resistance to that of Example 8 using
calcium nitrate as the coagulant.
TABLE-US-00002 TABLE 2 Difference Chemical in level Crack Crack or
resistance (.mu.m) inhibitor Coagulant pin hole (min.) Example 1
32.4 TiO.sub.2 acetic acid absence 22 Example 2 40.7 TiO.sub.2
acetic acid absence 22 Example 3 200.5 TiO.sub.2 acetic acid
absence 20 Example 4 15.1 TiO.sub.2 acetic acid absence 45 Example
5 31.9 SiO.sub.2 acetic acid absence 22 Example 6 32.1 -- acetic
acid absence 20 Example 7 33.5 TiO.sub.2 citric acid absence 24
Example 8 31.5 TiO.sub.2 calcium nitrate absence 20 Comp. 222.4
TiO.sub.2 acetic acid presence 1 Example 1 Comp. 643 TiO.sub.2
acetic acid presence 1 Example 2
[0081] As mentioned above, according to the present invention, the
difference in level occurring at the boundary portion between the
areas where a stretchable yarn is knitted and where it is not
knitted is reduced to 210 .mu.m or less, thereby making it possible
to provide a chemical-resistant, support-type glove in which no
cracks or pin holes are formed at the boundary portion between the
areas where the stretchable yarn is knitted and where it is not
knitted, and which is superior in chemical permeation-resistance
property and has a high degree of safety.
[0082] Further, from the comparison of the glove of Example 1 and
the glove of Example 6, the glove of Example 1 using the crack
inhibitor is superior in chemical resistance to that of Example
6.
[0083] Furthermore, from the comparison of the glove of Example 1
and the glove of Example 8, when the crack inhibitor is used, the
glove of Example 1 using the organic acid (acetic acid) as the
coagulant is superior in chemical resistance to that of Example 8
using calcium nitrate as the coagulant.
* * * * *