AU2018313404A1 - Knitted item - Google Patents

Description

Description

Title of Invention: KNITTED ITEM

Technical Field

[0001] The present invention relates to a knitted item

exhibiting insect-repelling performance and capable of

suppressing deterioration in mechanical properties.

Background Art

[0002] Patent Literature 1 describes an insect-repellent

fiber having a core-sheath structure. Here, the core

portion contains an insect repellent and is formed with a

thermoplastic resin, and the sheath portion is formed

with a thermoplastic resin. According to the insect

repellent fiber described in Patent Literature 1, insect

repelling performance can be exhibited.

[0003] Patent Literature 2 describes an insect-repellent

net constituted by an insect-repellent yarn which is a

monofilament. Here, the insect-repellent yarn has an

insect repellent-holding portion that holds a liquid

insect repellent; and a release controlling portion that

is disposed on the outer side of the insect repellent

holding portion and releases the insect repellent.

According to the insect-repellent net described in Patent

Literature 2, insect-repelling performance can be

exhibited.

11993082_1 (GHMatters) P112789.AU

Citation List

Patent Literature

[0004]Patent Literature 1

International Publication No. WO 2016/143809

Patent Literature 2

Japanese Utility Model No. 3196082

Summary of Invention

Technical Problem

[0005] According to Patent Literatures 1 and 2, the

insect-repelling performance can be exhibited. However,

the tensile strength and elongation ratio of the insect

repellent fiber or the insect-repellent yarn are liable

to be lowered with the aging degradation of the insect

repellent fiber or the insect-repellent yarn by allowing

the insect-repellent fiber or the insect-repellent yarn

to contain an insect repellent. In this case, there is a

risk that the mechanical properties (tensile strength and

elongation ratio) demanded of an insect-repellent fiber

or an insect-repellent yarn are not satisfied.

[0006] Thus, an object of the present invention is to

provide a knitted item exhibiting insect-repelling

performance and capable of suppressing deterioration in

mechanical properties.

Solution to Problem

11993082_1 (GHMatters) P112789.AU

[0007] The present invention is a knitted item

constituted by a plurality of yarns, wherein out of the

plurality of the yarns, one yarn or each of some yarns is

multifilament constituted by a plurality of monofilaments

and comprising an insect repellent.

[0008] As the knitted item, a knitted item having a

marquisette texture can be used. Here, the one yarn or

each of the some yarns can be used as yarn being other

than a chain stitch yarn in the marquisette texture.

[0009] The monofilaments can be each constituted by a

core-sheath structure having: a core portion containing

an insect repellent and being formed with a thermoplastic

resin; and a sheath portion covering the core portion and

being formed with a thermoplastic resin. The weight

ratio of the core portion to the sheath portion (core

portion: sheath portion) can be set to 1:9 to 9:1,

preferably 1:9 to 5:5, and more preferably 2:8 to 4:6.

The knitted item according to the present invention can

be used as a material for an insect-repellent product.

Advantageous Effects of Invention

[0010] According to the present invention, one yarn or

each of some yarns, out of a plurality of yarns, that

constitutes a knitted item is multifilament containing an

insect repellent and therefore can exhibit insect

repelling performance by releasing the insect repellent

outside the yarns. Moreover, the insect repellent is

11993082_1 (GHMatters) P112789.AU contained only the one yarn or the some yarns, and therefore use of other yarns can secure mechanical properties of the knitted item and suppress deterioration in the mechanical properties.

Brief Description of Drawings

[0011][Figure 1] Figure 1 is a diagram showing a

marquisette texture.

[Figure 2] Figure 2 is a diagram showing knitting of

three yarns that constitute a marquisette texture.

[Figure 3] Figure 3 is a section view of a monofilament

having a core-sheath structure.

[Figure 4] Figure 4 is a graph showing a relationship

between the number of insects having halted in knitted

items of Example 1 and Reference Example 1 and measuring

time.

[Figure 5] Figure 5 is a graph showing a relationship

between the number of insects having halted in knitted

items of Comparative Example 1 and Reference Example 1

and the measuring time.

[Figure 6] Figure 6 is a graph showing a relationship

between a strength retention ratio and the assumed number

of years elapsed for knitted items of Example 1 and

Comparative Example 1.

[Figure 7] Figure 7 is a graph showing a relationship

between an elongation retention ratio and the assumed

11993082_1 (GHMatters) P112789.AU number of years elapsed for knitted items of Example 1 and Comparative Example 1.

Description of Embodiments

[0012] A knitted item according to the present embodiment

is constituted by a plurality of yarns. First, one yarn

or some yarns, out of a plurality of the yarns, that

constitute the knitted item are described. The one yarn

or each of the some yarns is multifilament constituted by

a plurality of monofilaments. It is preferable that

these monofilaments each have a core-sheath structure.

Next, the other yarns excluding the above-described one

yarn or some yarns (multifilament having a core-sheath

structure) of a plurality of the yarns that constitute

the knitted item are described. It is preferable that

these other filaments each be a multifilament, and the

monofilaments that constitute this multifilament each

have a single-layered structure and do not have a core

sheath structure.

[0013] As the knitted item, for example, a knitted item

having a marquisette texture can be used. The

marquisette texture is such that twisted yarns are used

and made into leno weave. Figure 1 shows a marquisette

texture, and Figure 2 shows knitting of each of three

yarns A to C that constitute the marquisette texture.

The yarn A is chain-stitched, and the yarns B and C are

each an insertion yarn entangled with the yarn A. By

11993082_1 (GHMatters) P112789.AU combining the yarns A to C shown in Figure 2, the marquisette texture shown in Figure 1 is obtained.

[0014] Each of the yarns A to C is a multifilament. One

yarn or each of some yarns, out of the yarns A to C, is a

multifilament constituted by a plurality of monofilaments

each having a core-sheath structure, and the other yarns

are each a multifilament constituted by a plurality of

monofilaments not having a core-sheath structure.

[0015] For example, at least one of the yarns B and C,

which are other than the chain stitch yarn A, can be a

multifilament constituted by a plurality of monofilaments

each having a core-sheath structure. In this case, as

the yarn A, a multifilament constituted by monofilaments

not having a core-sheath structure is used. Preferably,

only the yarn C can be a multifilament constituted by a

plurality of monofilaments each having a core-sheath

structure. In this case, as the yarns A and B,

multifilaments each constituted by monofilaments not

having a core-sheath structure are used.

[0016] As will be described later, an insect repellent is

contained in the core portion of the monofilament having

a core-sheath structure, and therefore the insect

repellent can be released outside the monofilament. As

shown in Figure 2, the yarns B and C extend in the

transverse direction in Figure 2, as compared to the yarn

A. Therefore, when at least one of the yarns B and C is

a multifilament constituted by a plurality of

11993082_1 (GHMatters) P112789.AU monofilaments each having a core-sheath structure, releasing the insect repellent from the whole surface of the knitted item is thereby made easy. As a result, the insect-repelling performance can be easy to be exhibited.

[0017] The knitted item according to the present

invention is not limited to a knitted item having a

marquisette texture. That is, the knitted item according

to the present invention may be a knitted item

constituted by a plurality of yarns, wherein one yarn or

each of some yarns out of a plurality of the yarns is

multifilament constituted by a plurality of

monofilaments, as described above, and it is preferable

that the monofilaments each have a core-sheath structure.

The knitted item according to the present invention is

used as a material for an insect-repellent product.

Examples of the insect-repellent product include an

agricultural insect-repellent net, a panel screen door, a

roll screen door, an accordion type screen door, a

mosquito net, clothes, a hat, and a muffler. When an

insect-repellent net, a screen net, or a mosquito net is

made, flameproofing or hard-finishing is preferably

performed depending on the desired application. When

flameproofing is performed, an organic (such as organic

phosphorus-based or bromine (halogen)-based) and/or an

inorganic (such as metal hydroxide-based, inorganic

phosphorus-based, boron-based, or silica-based)

flameproofing agent can appropriately be used. When

11993082_1 (GHMatters) P112789.AU hard-finishing is performed, there is no particular limitations on resins, and acrylic resins, polyester resins, glyoxal-based resins, melamine resins, urea resins, phenol resins, polyurethane resins, silicon resins, alkyd resins, vinyl chloride resins, fluororesins, cellulose-based resins, UV curable resins, and the like can be used.

[0018]

Next, the monofilament having a core-sheath

structure will be described with reference to Figure 3.

[0019] A monofilament 1 has a core portion 2 and a sheath

portion 3. The core portion 2 is composed of a

thermoplastic resin, and an insect repellent 4 is held by

the core portion 2 in a state where it is dispersed

inside the core portion 2. The sheath portion 3 is

composed of a thermoplastic resin and is in contact with

the outer surface of the core portion 2, thereby covering

the core portion 2. The insect repellent 4 is released

outside the monofilament 1 from the outer surface of the

sheath portion 3 after moving from the core portion 2 to

the sheath portion 3. When this monofilament 1 has a

core-sheath structure, sustained releasability can

thereby be improved.

[0020] The thermoplastic resins that constitute the core

portion 2 and the sheath portion 3 are not particularly

limited as long as they can keep the shapes of the core

portion 2 and the sheath portion 3 and can release the

11993082_1 (GHMatters) P112789.AU insect repellent 4 outside the monofilament 1. Here, the thermoplastic resins that constitute the core portion 2 and the sheath portion 3 may be the same or different.

[0021] Examples of the thermoplastic resins include

polyesters, polyethylene, polypropylene, polyvinyl

chloride, polyethylene terephthalate, polybutylene

terephthalate, polytetramethylene terephthalate, nylon,

acrylics, polyvinylidene fluoride, poly(ethylene-co

tetrafluoroethylene), polytetrafluoroethylene, polyvinyl

alcohol, Kevlar (registered trademark), polyacrylic acid,

poly(methyl methacrylate), rayon, cupra, Tencel

(registered trademark), polynosic, acetates, and

triacetates.

[0022] Among these thermoplastic resins, as the

thermoplastic resins that constitute the core portion 2

and the sheath portion 3, crystalline thermoplastic

resins can be used from the viewpoint of securing the

strength of the core portion 2 and the sheath portion 3.

Specific examples of the crystalline thermoplastic resins

include polyethylene, polypropylene, polyethylene

terephthalate, polybutylene terephthalate, nylon, and

polyvinylidene fluoride. Among these, as the

thermoplastic resin which is easily melt-spun into the

monofilament 1, polyethylene, polypropylene, polyethylene

terephthalate, polybutylene terephthalate, and the like

are more preferably used.

11993082_1 (GHMatters) P112789.AU

[0023] A monofilament not having a core-sheath structure

can also be formed with the above described thermoplastic

resin. Moreover, in the present embodiment, the insect

repellent 4 is contained only in the core portion 2, but

the insect repellent 4 can be contained only in the

sheath portion 3, or the insect repellent 4 can be

contained in both of the core portion 2 and the sheath

portion 3.

[0024] In the present embodiment, the degree of

crystallinity of the thermoplastic resin that constitutes

the sheath portion 3 can be set to equal to or less than

the degree of crystallinity of the thermoplastic resin

that constitutes the core portion 2. The degree of

crystallinity of a thermoplastic resin depends on the

material of the thermoplastic resin, and the heating

temperature and stretch ratio in performing heat

stretching after melt-spinning. Accordingly, when the

relationship among the degree of crystallinity, the

materials of the thermoplastic resins, and the heating

temperature and stretch ratio in performing heat

stretching after melt-spinning is determined in advance,

the materials of the thermoplastic resins, and the

heating temperature and stretch ratio in performing heat

stretching after melt-spinning can be set so that the

degree of crystallinity of the thermoplastic resin that

constitutes the sheath portion 3 will be equal to or less

11993082_1 (GHMatters) P112789.AU than the degree of crystallinity of the thermoplastic resin that constitutes the core portion 2.

[0025] When the heat-stretching is not performed, the

materials of the thermoplastic resins may be set so that

the degree of crystallinity of the thermoplastic resin

that constitutes the sheath portion 3 will be equal to or

less than the degree of crystallinity of the

thermoplastic resin that constitutes the core portion 2.

Moreover, the degree of crystallinity of the

thermoplastic resins that constitute the core portion 2

and the sheath portion 3 can be measured by, for example,

a powder X-ray diffraction method. The degree of

crystallinity of the thermoplastic resin that constitutes

the core portion 2 can be regarded as the same as the

degree of crystallinity of the thermoplastic resin that

constitutes a core portion 2 (fiber) of a single-layered

structure formed under the same conditions as the

conditions under which the core portion 2 is formed.

[0026] When the degree of crystallinity of the

thermoplastic resin that constitutes the sheath portion 3

is equal to or less than the degree of crystallinity of

the thermoplastic resin that constitutes the core portion

2, the insect repellent 4 is easily allowed to move

mainly in an amorphous portion of the sheath portion 3,

so that the insect repellent 4 can be released outside

the monofilament 1. Thereby, the insect-repelling

performance can be exhibited. Here, when the degree of

11993082_1 (GHMatters) P112789.AU crystallinity of the thermoplastic resin that constitutes the sheath portion 3 is larger than the degree of crystallinity of the thermoplastic resin that constitutes the core portion 2, it is difficult for the insect repellent 4 to move in the sheath portion 3, making the insect repellent 4 less likely to be released outside the monofilament 1 difficult, so that the insect-repelling performance is liable to be deteriorated.

[0027] The degree of crystallinity of the thermoplastic

resin that constitutes the core portion 2 is preferably

10% or more and 100% or less, and more preferably 40% or

more and 100% or less. The degree of crystallinity of

the thermoplastic resin that constitutes the sheath

portion 3 may be equal to or less than the degree of

crystallinity of the thermoplastic resin that constitutes

the core portion 2, and, specifically, is preferably set

to be equal to or less than the degree of crystallinity

(10% or more and 100% or less) of the thermoplastic resin

that constitutes the core portion 2 within a range of 10%

or more and 100% or less, and more preferably set to be

equal to or less than the degree of crystallinity (40% or

more and 100% or less) of the thermoplastic resin that

constitutes the core portion 2 within a range of 40% or

more and 100% or less. Still more preferably, the degree

of crystallinity of the thermoplastic resin that

constitutes the sheath portion 3 can be set to 10% or

11993082_1 (GHMatters) P112789.AU more and 80% or less, and further still more preferably

40% or more and 80% or less.

[0028] The weight ratio of the core portion 2 to the

sheath portion 3 (core portion 2: sheath portion 3) may

be 1:9 to 9:1. In the present embodiment, the insect

repellent 4 is contained in the core portion 2, and the

weight of the core portion 2 as referred to herein is the

weight of the core portion 2 excluding the insect

repellent 4. When the weight ratio of the core portion 2

to the sheath portion 3 is out of the upper limit value

(1:9) of the above-described range, the weight of the

sheath portion 3 (in other words, thickness of sheath

portion 3) is too large relative to the weight of the

core portion 2 (in other words, diameter of core portion

2). Therefore, the insect repellent 4 contained in the

core portion 2 is less likely to be released to the

outside of the monofilament 1. On the other hand, when

the weight ratio of the core portion 2 to the sheath

portion 3 is out of the lower limit value (9:1) of the

above-described range, the weight of the sheath portion 3

is too small relative to the weight of the core portion

2, so that the insect repellent 4 contained in the core

portion 2 is released excessively outside the

monofilament 1. The weight ratio of the core portion 2

to the sheath portion 3 is preferably 1:9 to 5:5, and

more preferably 2:8 to 4:6.

11993082_1 (GHMatters) P112789.AU

[0029] The insect repellent 4 held in the core portion 2

is not particularly limited as long as the insect

repellent 4 is left in the core portion 2 of the

monofilament 1 in performing melt-spinning the

monofilament 1, and can appropriately be selected by

those skilled in the art. For example, a

microencapsulated insect repellent 4 can be used, or the

insect repellent 4 can be carried on a porous material.

[0030] In the present embodiment, the microencapsulated

insect repellent 4 is preferably used. The

microencapsulated insect repellent 4 is such that the

insect repellent 4 is filled as a liquid compound in a

microcapsule. When the monofilament 1 is melt-spun using

a crystalline thermoplastic resin, the insect repellent 4

migrates into an amorphous portion of the thermoplastic

resin, and the insect repellent 4 that cannot halt in the

amorphous portion bleeds out onto the outer surface of

the monofilament 1. Therefore, tackiness (adhesiveness)

occurs to make weaving difficult, and the insect

repellent 4 in an amount that is more than necessary is

needed at the time of melt-spinning. The use of the

microencapsulated insect repellent 4 allows the insect

repellent 4 as a liquid compound to halt in the

microcapsule at the time of melt-spinning, and can

suppress the migration of the insect repellent 4 into the

amorphous portion of the thermoplastic resin. Therefore,

the bleed-out of the insect repellent 4 onto the outer

11993082_1 (GHMatters) P112789.AU surface of the monofilament 1 can be less likely to occur. This can make the tackiness less likely to occur and can suppress the use of the insect repellent 4 in an amount that is more than necessary.

[0031] Moreover, in the present embodiment, an insect

repellent 4 carried on an inorganic compound that

controls the release of the insect repellent 4 is

preferably used. Examples of the inorganic compound that

controls the release of the insect repellent 4 include

inorganic compounds which are particulate, fibrous,

plate-like, scale-like, or layered. Moreover, these

inorganic compounds are further desirably porous

materials in order to increase the surface area in which

the insect repellent 4 can be carried. The use of the

insect repellent 4 carried on the inorganic compound that

controls the release of the insect repellent 4 can make

the bleed-out of the insect repellent 4 onto the outer

surface of the monofilament 1 less likely to occur. This

can make the tackiness less likely to occur and can

release the insect repellent 4 in a minimum amount that

is necessary for enabling the insect-repelling

performance to be exhibited.

[0032] The insect repellent 4 of the present embodiment

is preferably contained as a liquid compound in the

monofilament 1. The use of the insect repellent 4 being

a liquid compound enables adding the insect repellent 4

in the core portion 2 at a high concentration in a stable

11993082_1 (GHMatters) P112789.AU state and makes it easy to adjust the diffusion speed of the insect repellent 4 in the inside of the monofilament

1. Moreover, the main component of the insect repellent

4 is not particularly limited, but is preferably in the

form of liquid at normal temperature. Specific examples

of the main component of the insect repellent 4 include

pyrethroid-based insect repellents such as pyrethrin,

cinerin, jasmoline, allethrin, resmethrin, fenvalerate,

and permethrin; cyclic diene-based insect repellents such

as toxaphene and benzoepin; organic phosphorus-based

insect repellents such as malathion and fenitrothion; and

carbamate-based insect repellents such as carbaryl,

methomyl, and promecarb. These insect repellents can be

used singly or in combinations of two or more thereof.

Among these insect repellents, pyrethroid-based insect

repellents having excellent insect-repelling performance

and fast acting property and being less likely to show

acute toxicity are suitable. Moreover, among the

pyrethroid-based insect repellents, permethrin and

etfenprox, which easily exhibit the insect-repelling

performance at a low concentration and by which safety to

humans and animals are easily secured, are suitable.

[0033] In the present embodiment, the insect repellent 4

contained in the core portion 2 passes through the sheath

portion 3 in the monofilament 1 having the core portion 2

and the sheath portion 3 and is released outside the

monofilament 1, and therefore the release of the insect

11993082_1 (GHMatters) P112789.AU repellent 4 can be adjusted in the sheath portion 3.

Diffusion of the insect repellent 4 outside the

monofilament 1 can also be suppressed, so that the safety

to humans and animals can be secured, and the duration of

the insect-repelling performance can be extended.

[0034] The monofilament 1 in the present embodiment

contains the insect repellent 4 in the core portion 2,

and the insect repellent 4 passes through the sheath

portion 3, and therefore the bleed-out of the insect

repellent 4 on the surface of the monofilament 1 can be

suppressed, so that the tackiness can be made less likely

to occur. Therefore, when a knitted item is knit using

multifilaments each composed of a plurality of

monofilaments 1, the knitted item is knitted easily.

[0035] Moreover, when the tackiness is liable to occur on

the surface of the monofilament, dust or the like is

liable to adhere to the surface of the monofilament. The

dust or the like that has adhered to the surface of the

monofilament is not preferable because it inhibits the

release of the insect repellent from the monofilament to

deteriorate the insect-repelling performance. Moreover,

when the monofilament is washed (for example, washed with

water) in order to remove the dust or the like that has

adhered to the monofilament, the insect repellent is

removed together with the dust or the like and the

release of the insect repellent from the monofilament is

11993082_1 (GHMatters) P112789.AU facilitated, so that the duration of the insect-repelling performance is shortened.

[0036] On the other hand, in the present embodiment, the

bleed-out of the insect repellent 4 on the surface of the

monofilament 1 can be suppressed, as described above, and

therefore adhesion of the dust or the like to the surface

of the monofilament 1 can easily be suppressed, and the

inhibition of the release of the insect repellent 4 by

the dust or the like can be suppressed. Moreover, the

number of times of washing the monofilament 1 is

suppressed, and therefore the removal of the insect

repellent 4 due to washing can be suppressed, so that the

duration of the insect-repelling performance can be

extended.

[0037] The method for producing the monofilament 1 can

appropriately be selected by those skilled in the art and

is not particularly limited. For example, as a

reasonable and inexpensive method for producing the

monofilament 1, there is a method in which the insect

repellent 4 is filled in a thermoplastic resin that

constitutes the core portion 2 of the monofilament 1, and

the core portion 2 and the sheath portion 3 are then

melt-spun. Specifically, a master batch pellet is

produced in advance with a pellet such as a thermoplastic

resin containing a liquid insect repellent 4, and a

pellet of the same thermoplastic resin as the master

batch pellet is mixed with the master batch pellet in a

11993082_1 (GHMatters) P112789.AU certain ratio to produce the core portion 2.

Subsequently, a pellet of a thermoplastic resin is used

as the sheath portion 3 to produce the monofilament 1

using a known core-sheath spinning apparatus.

[0038] After the monofilament 1 is spun, heat-stretching

can be performed. By controlling the heating temperature

in performing heat-stretching and the stretch ratio by

heat-stretching, the degree of crystallinity of the

thermoplastic resin, the outer diameter of the

monofilament 1, and the like can be controlled.

[0039] In the present embodiment, the content rate of the

insect repellent 4 in the monofilament 1 is preferably

0.1% by mass or more and 10% by mass or less based on the

monofilament 1. When the content rate of the insect

repellent 4 is less than 0.1% by mass, the insect

repelling performance is deteriorated and the duration of

the insect-repelling performance is shortened, as

compared to the case where the content rate of the insect

repellent 4 is 0.1% by mass or more. When the content

rate of the insect repellent 4 exceeds 10% by mass, the

mass% of the resin of the core portion 2 and the sheath

portion 3, which make the skeleton of the monofilament 1,

is lowered, so that the strength of the monofilament 1 is

lowered, as compared to the case where the content rate

of the insect repellent 4 is 10% by mass or less.

Further, the tackiness is liable to occur, and therefore

a knitted item is difficult to knit. Moreover, although

11993082_1 (GHMatters) P112789.AU it depends on the thickness of the sheath portion 3, the higher the content rate of the insect repellent 4, the larger the amount of the insect repellent 4 released at the surface of the monofilament 1 is. As a result, the intake of the insect repellent 4 by humans and animals increases. The content rate of the insect repellent 4 in the monofilament 1 is more preferably 0.1% by mass or more and 5% by mass or less based on the monofilament 1.

When the content rate of the insect repellent 4 is 0.1%

by mass or more and 5% by mass or less, the tackiness is

less likely to occur, so that a knitted item is knitted

easily. Further, the insect repellent 4 is less likely

to be released excessively, so that the safety to humans

and the like can be made to be secured easily.

[0040] Moreover, the monofilament 1 or the monofilament

having a single-layered structure may contain as a

functional material a component for imparting an

arbitrary function. The functional material include

titanium dioxide and silica as delustering agents;

calcium stearate as a lubricant; fine particles such as

silica and alumina; hindered phenol derivatives as

antioxidants; a colorant such as a pigment; additive

materials such as a stabilizer and a dispersant; and

other functional materials such as an ultraviolet ray

shielding agent, a near infrared shielding agent, an

antibacterial agent, an anti-mold agent, an anti-static

agent, a flame retardant, a weatherproofing agent, and

11993082_1 (GHMatters) P112789.AU various catalysts. When a functional material is contained in the monofilament 1, the functional material may exist in the core portion 2 by being dispersed with the insect repellent 4, may exist in the sheath portion 3 by being dispersed, or may adhere to the surface of the monofilament 1. Moreover, when a functional material is contained in the monofilament having a single-layered structure, the functional material may exist inside the monofilament by being dispersed, or may adhere to the surface of the monofilament.

[0041] Moreover, fine unevenness may be formed by

chemically bonding inorganic fine particles to the

surface of the monofilament 1 or the surface of the

monofilament having a single-layered structure. By

forming the fine unevenness, dust or the like floating in

the air is made less likely to adhere to the surface of

the monofilament. Moreover, even when the dust or the

like has adhered to the surface of the monofilament, only

the dust can easily be removed with water or the like

without removing the insect repellent 4 exposed at the

surface of the monofilament. Therefore, a monofilament

having an excellent dustproof property can be made.

[0042] The sectional shape of the monofilament 1 or the

sectional shape of the monofilament having a single

layered structure can be a modified shape such as a

circle, flat, triangle, hollow, or modified shape such as

star shape. Among the above-described sectional shapes,

11993082_1 (GHMatters) P112789.AU the sectional shape of the monofilament is preferably circular from the viewpoint of wear resistance, attitude stability, and smoothness.

[0043] Hereinafter, Examples of the present invention

will be described.

[0044](Example 1)

(Production of Insect-repelling Yarn)

A master batch pellet composed of a highly

crystalline homo polypropylene resin containing

permethrin (insect repellent) was prepared. A pellet

composed of a highly crystalline homo polypropylene resin

was prepared. The master batch pellet and a highly

crystalline homo polypropylene resin were melted and

mixed to obtain a mixture containing a predetermined

content rate of permethrin. The obtained mixture and the

prepared pellet were each melted using a melt-extruder

provided in a melt-spinning apparatus.

[0045] The molten mixture and pellet were ejected from a

spinneret for core-sheath type composite fiber, the

spinneret provided in the melt-spinning apparatus, and

taken up at a predetermined speed while being cooled in a

water tank, thereby obtaining a monofilament having a

core-sheath structure. The obtained monofilament was

drawn while being allowed to pass through a warm water

(stretching bath) heated at a predetermined temperature,

and was thereby stretched to a predetermined stretch

ratio. The stretched monofilament was allowed to pass

11993082_1 (GHMatters) P112789.AU through a set tank and wound around a bobbin to obtain a monofilament having a core-sheath structure, the monofilament having a weight ratio of the core portion to the sheath portion (core portion: sheath portion) of 3:7.

Here, the core portion of the monofilament is composed of

the highly crystalline homo polypropylene (PP) resin

containing permethrin, and the sheath portion of the

monofilament is composed of a polyethylene terephthalate

(PET) resin. An insect-repelling yarn being a

multifilament (75 denier, 24 filaments) was produced

using this monofilament. The content rate of permethrin

based on the obtained insect-repelling yarn was 1% by

mass.

[0046](Production of Knitted Item)

A knitted item having a marquisette texture composed

of three yarns was produced using the obtained insect

repelling yarn. Here, the obtained insect-repelling yarn

was used as the yarn C of the three yarns A to C shown in

Figure 2. A multifilament (75 denier, 24 filaments)

composed of a monofilament having a single-layered

structure was used as the yarns A and B. The

monofilament having a single-layered structure was

produced using a polyethylene terephthalate (PET) resin.

[0047](Comparative Example 1)

The insect-repelling yarn obtained in Example 1 was

used as the three yarns that constitute the marquisette

11993082_1 (GHMatters) P112789.AU texture. A knitted item having a marquisette texture was produced using the three insect-repelling yarns.

[0048](Reference Example 1)

A yarn composed of a polyethylene terephthalate

(PET) resin was used as the three yarns that constitute

the marquisette texture. These yarns are multifilaments

(75 denier, 24 filaments) each constituted by a plurality

of monofilaments (single-layered structure) each composed

of the PET resin. A knitted item having a marquisette

texture was produced using the above-described three

yarns.

[0049](Method for Evaluating Insect-repelling

Performance)

The insect-repelling performance was evaluated using

each of the knitted items of Example 1, Comparative

Example 1, and Reference Example 1 as an insect-repellent

net. The method for evaluating the insect-repelling

performance is as follows.

[0050] A screen door frame having each insect-repellent

net installed separately therein (frame size: 43 cm x 37

cm, insect-repellent net size: 34 cm x 33 cm) was

installed outdoor, and the number of insects which had

halted on each insect-repellent net for 5 seconds or more

was measured visually. Here, the insect-repellent nets

of Example 1 and Reference Example 1 were placed side by

side at the same place and left to stand for 5 days.

Moreover, the insect-repellent nets of Comparative

11993082_1 (GHMatters) P112789.AU

Example 1 and Reference Example 1 were placed side by

side at the same place and left to stand for 5 days. The

period (date) during which the insect-repellent nets of

Example 1 and Reference Example 1 are left to stand and

the period (date) during which the insect-repellent nets

of Comparative Example 1 and Reference Example 1 are left

to stand are different from each other.

[0051] The measurement of the number of insects was

carried out three times a day at fixed time (10:00,

15:00, 17:30). When the total number of insects which

have halted on the insect-repellent net for 5 seconds or

more is at least one in each measurement day, the insect

repelling performance is rated as poor, and when the

total number of insects which have halted on the insect

repellent net for 5 seconds or more is zero, the insect

repelling performance is rated as good.

[0052](Results of Evaluating Insect-repelling

Performance)

Figure 4 and Figure 5 show the results of measuring

the number of insects. Figure 4 shows the measurement

results with respect to the insect-repellent nets of

Example 1 and Reference Example 1, and Figure 5 shows the

measurement results with respect to the insect-repellent

nets of Comparative Example 1 and Reference Example 1.

In each of Figure 4 and Figure 5, the vertical axis shows

the number of insects which have halted for 5 seconds or

more (referred to as the number of insects), and the

11993082_1 (GHMatters) P112789.AU horizontal axis shows the measurement day and the measurement time.

[0053] With respect to Reference Example 1, the number of

insects was sometimes zero depending on the measurement

time, but the total number of insects per day was at

least one. With respect to Example 1 and Comparative

Example 1, the number of insects was zero irrespective of

the measurement time in all of the measurement days.

From this fact, it was found that the insect-repellent

nets of Example 1 and Comparative Example 1 have

excellent insect-repelling performance. Moreover,

according to the above-described evaluation method, the

evaluation results shown in Table 1 below were obtained.

[0054]

[Table 1]

Insect-repelling performance Example 1 Good Comparative Example 1 Good Reference Example 1 Poor

[0055](Method for Evaluating Weatherability)

The weatherability of the insect-repellent nets of

Example 1 and Comparative Example 1 was evaluated. As

the testing method for the weatherability, the insect

repellent nets were irradiated with ultraviolet rays in a

laboratory under conditions specified in JIS A1415(2013).

The tensile strength [N] and the elongation ratio [%] of

the insect-repellent nets were measured before and after

11993082_1 (GHMatters) P112789.AU the weatherability test by the tensile test in accordance with JIS L1096. In the weatherability test, two assumed numbers of years elapsed (two years and six years) were set by changing the irradiation time with the ultraviolet rays.

[0056](Results of Evaluating Weatherability)

The ratio of tensile strengths (Example

1/Comparative Example 1) and the ratio of elongation

ratios (Example 1/Comparative Example 1) for the insect

repellent nets of Example 1 and Comparative Example 1

before carrying out the weatherability test are shown in

Table 2 below. As can be seen from Table 2 below, the

tensile strength of the insect-repellent net of Example 1

was 2 times the tensile strength of the insect-repellent

net of Comparative Example 1. Moreover, the elongation

ratio of the insect-repellent net of Example 1 was 1.3

times the elongation ratio of the insect-repellent net of

Comparative Example 1.

[0057]

[Table 2]

Ratio of tensile Ratio of elongation strengths ratios Example 1/Comparative Example 1 2.0 1.3

[0058] On the other hand, the strength retention ratio

with respect to the tensile strength of the insect

repellent net and the elongation retention ratio with

respect to the elongation ratio of the insect-repellent

11993082_1 (GHMatters) P112789.AU net were calculated for Example 1 and Comparative Example

1.

[0059] The strength retention ratio refers to a ratio of

the tensile strength of the insect-repellent net after

the weatherability test to the tensile strength of the

insect-repellent net before the weatherability test.

When the tensile strength of the insect-repellent net is

not changed before and after the weatherability test, the

strength retention ratio is 100 [%]. On the other hand,

when the tensile strength of the insect-repellent net is

lowered depending on the degradation of the insect

repellent net over time, the strength retention ratio is

lowered to less than 100 [%].

[0060] The elongation retention ratio refers to a ratio

of the elongation ratio of the insect-repellent net after

the weatherability test to the elongation ratio of the

insect-repellent net before the weatherability test.

When the elongation ratio of the insect-repellent net is

not changed before and after the weatherability test, the

elongation retention ratio is 100 [%]. On the other

hand, when the elongation ratio of the insect-repellent

net is lowered depending on the degradation of the

insect-repellent net over time, the elongation retention

ratio is lowered to less than 100 [%].

[0061] Figure 6 shows the results of calculating the

strength retention ratio at two assumed numbers of years

elapsed (two years and six years) for Example 1 and

11993082_1 (GHMatters) P112789.AU

Comparative Example 1. In Figure 6, the vertical axis

shows the strength retention ratio, and the horizontal

axis shows the assumed number of years elapsed.

According to Figure 6, it was found that the strength

retention ratio of the insect-repellent net of Example 1

is less likely to be lowered as compared to that of the

insect-repellent net of Comparative Example 1.

[0062] The strength retention ratio of the insect

repellent net of Comparative Example 1 was extremely

lowered to about 40% when the assumed number of years

elapsed reached two years, but the strength retention

ratio of the insect-repellent net of Example 1 was 80% or

more even when the assumed number of years elapsed

reached two years. Moreover, when the assumed number of

years elapsed reached six years, the strength retention

ratio of Example 1 was 67%, but the strength retention

ratio of Comparative Example 1 was 25%. As can be seen

from this fact, according to the insect-repellent net of

Example 1, lowering the tensile strength is easily

suppressed.

[0063] Figure 7 shows the results of calculating the

elongation retention ratio at two assumed numbers of

years elapsed (two years and six years) for Example 1 and

Comparative Example 1. In Figure 7, the vertical axis

shows the elongation retention ratio, and the horizontal

axis shows the assumed number of years elapsed.

According to Figure 7, it was found that the elongation

11993082_1 (GHMatters) P112789.AU retention ratio of the insect-repellent net of Example 1 is less likely to be lowered as compared to that of the insect-repellent net of Comparative Example 1.

[0064] The elongation retention ratio of the insect

repellent net of Comparative Example 1 was extremely

lowered to about 20% when the assumed number of years

elapsed reached two years, but the elongation retention

ratio of the insect-repellent net of Example 1 was 80% or

more even when the assumed number of years elapsed

reached two years. Moreover, when the assumed number of

years elapsed reached six years, the elongation retention

ratio of Example 1 was 54%, but the elongation retention

ratio of Comparative Example 1 was 8%. As can be seen

from this fact, according to the insect-repellent net of

Example 1, lowering the elongation ratio is easily

suppressed.

Reference Signs List

[0065] 1: Monofilament

2: Core portion

3: Sheath portion

4: Insect repellent

11993082_1 (GHMatters) P112789.AU

Claims (6)

1. Claims

   [Claim 1]

   A knitted item constituted by a plurality of yarns,

   wherein

   out of the plurality of the yarns, one yarn or each

   of some yarns is multifilament constituted by a plurality

   of monofilaments and comprising an insect repellent.
2. [Claim 2]

   The knitted item according to claim 1, having a

   marquisette texture.
3. [Claim 3]

   The knitted item according to claim 2, wherein the

   one yarn or each of the some yarns is yarn being other

   than a chain stitch yarn in the marquisette texture.
4. [Claim 4]

   The knitted item according to any one of claims 1 to

   3, wherein the monofilaments each have a core-sheath

   structure having:

   a core portion comprising the insect repellent and

   being formed with a thermoplastic resin; and

   a sheath portion covering the core portion and being

   formed with a thermoplastic resin.
5. [Claim 5]

   The knitted item according to claim 4, wherein a

   weight ratio of the core portion to the sheath portion is

   1:9 to 9:1.

   11993082_1 (GHMatters) P112789.AU
6. [Claim 6]

   The knitted item according to any one of claims 1 to

   5, wherein the knitted item is for use as a material for

   an insect-repellent product.

   11993082_1 (GHMatters) P112789.AU