JP7127029B2 - knitting - Google Patents

Description

TECHNICAL FIELD The present invention relates to a knitted fabric capable of suppressing deterioration of mechanical properties while exhibiting insect repellent performance.

Patent Document 1 describes an insect repellent fiber having a core-sheath structure. Here, the core contains an insect repellent and is made of a thermoplastic resin, and the sheath is made of a thermoplastic resin. According to the insect repellent fiber described in Patent Document 1, insect repellent performance can be exhibited.

Patent Literature 2 describes an insect net composed of monofilament insect repellent threads. Here, the insect repellent thread has an insect repellent holding part that holds a liquid insect repellent and a release control part that is arranged outside the insect repellent holding part and releases the insect repellent. According to the insect net described in Patent Document 2, insect repellent performance can be exhibited.

International Publication No. 2016/143809 pamphlet Utility Model Registration No. 3196082

According to Patent Documents 1 and 2, it is possible to exhibit insect repellent performance, but due to the inclusion of the insect repellent, the tensile strength and elongation of the insect repellent fiber and insect repellent thread deteriorate with age. rate tends to decline. In this case, the mechanical properties (tensile strength and elongation) required for the insect repellent fiber or thread may not be satisfied.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a knitted fabric capable of suppressing a decrease in mechanical properties while exhibiting insect repellent performance.

The present invention is a knitted fabric composed of a plurality of yarns, and a part of the yarns of the plurality of yarns is a multifilament composed of a plurality of monofilaments and containing an insect repellent.

As the knitted fabric, a knitted fabric having a marquisette structure can be used. Here, the partial number of yarns can be used as yarns other than chain stitch yarns in the marquisette weave.

The monofilament can have a core-sheath structure containing an insect repellent and having a core made of a thermoplastic resin and a sheath made of a thermoplastic resin covering the core. The weight ratio of the core and the sheath (core:sheath) is 1:9 to 9:1, preferably 1:9 to 5:5, more preferably 2:8 to 4:6. can. The knitted fabric of the present invention can be used as a material for insect repellent products.

According to the present invention, since some of the yarns constituting the knitted fabric are multifilaments containing an insect repellent, the insect repellent is released to the outside of the yarn to exhibit insect repellent performance. can be made In addition, since the insect repellent is contained in only a part of the yarns, it is possible to secure the mechanical properties of the knitted fabric by using other yarns, and to suppress the deterioration of the mechanical properties.

FIG. 13 shows a marquisette organization; Fig. 3 shows the knitting of the three threads that make up the marquisette weave; 1 is a cross-sectional view of a monofilament having a core-sheath structure; FIG. FIG. 2 is a diagram showing the relationship between the number of insects lodged on knitted fabrics of Example 1 and Reference Example 1 and the measurement time. FIG. 3 is a diagram showing the relationship between the number of insects lodged on the knitted fabrics of Comparative Example 1 and Reference Example 1 and the measurement time. FIG. 2 is a diagram showing the relationship between the strength retention rate and assumed elapsed years for the knitted fabrics of Example 1 and Comparative Example 1. FIG. FIG. 2 is a diagram showing the relationship between the elongation retention rate and assumed elapsed years for the knitted fabrics of Example 1 and Comparative Example 1. FIG.

The knitted fabric of this embodiment is composed of a plurality of yarns. First, a partial number of yarns among the plurality of yarns forming the knitted fabric will be described. This partial number of threads is a multifilament composed of a plurality of monofilaments. This monofilament preferably has a core-sheath structure. Next, yarns other than the above-described partial number of yarns (multifilament having a core-sheath structure) among the plurality of yarns constituting the knitted fabric will be described. This other thread is preferably a multifilament, and the monofilaments constituting this multifilament have a single layer structure and do not have a core-sheath structure.

As the knitted fabric, for example, a knitted fabric having a marquisette structure can be used. Marquisette weave is leno weave using twisted yarns. FIG. 1 shows a marquisette weave, and FIG. 2 shows the knitting of each of the three yarns A to C that make up the marquisette weave. Yarn A is a chain stitch, and Yarns B and C are insertion threads that are entwined with Yarn A. By combining the yarns A to C shown in FIG. 2, the marquisette weave shown in FIG. 1 is obtained.

Each of yarns AC is multifilament. Some of the yarns A to C are multifilaments composed of a plurality of monofilaments having a core-sheath structure, and the remaining yarns are composed of a plurality of monofilaments that do not have a core-sheath structure. Multifilament.

For example, at least one of the yarns B and C other than the chain stitch yarn A can be a multifilament composed of a plurality of monofilaments having a core-sheath structure. In this case, as the thread A, a multifilament composed of monofilaments having no core-sheath structure is used. Preferably, only yarn C can be a multifilament composed of a plurality of monofilaments having a core-sheath structure. In this case, the yarns A and B are multifilaments composed of monofilaments that do not have a core-sheath structure.

As will be described later, in a monofilament having a core-sheath structure, since the insect repellent is contained in the core part, the insect repellent can be released to the outside of the monofilament. As shown in FIG. 2, the yarns B and C are wider in the lateral direction of FIG. 2 than the yarn A, so at least one of the yarns B and C is composed of a plurality of monofilaments having a core-sheath structure By forming the multifilament into a multifilament, it becomes easy to release the insect repellent from the entire surface of the knitted fabric, and it becomes easy to exhibit the insect repellent performance.

In addition, the knitted fabric of the present invention is not limited to a knitted fabric having a marquisette structure. That is, the knitted fabric is composed of a plurality of yarns, and among the plurality of yarns, a part of the yarns may be a multifilament composed of a plurality of monofilaments, as described above. It preferably has a core-sheath structure. The knitted fabric of the present invention is used as a material for insect repellent products. Insect control products include, for example, agricultural insect screens, panel screens, roll screens, accordion screens, mosquito nets, clothing, hats, and mufflers. Insect nets, screen doors, and mosquito nets are preferably made by flame-retardant processing or hard finishing depending on the intended use. In the case of flame retardant processing, organic (organic phosphorus, bromine (halogen), etc.) and / or inorganic (metal hydroxide, inorganic phosphorus, boron, silica, etc.) Flaming agents can be used. In the case of hard finishing, the resin is not particularly limited, acrylic resin, polyester resin, glyoxal resin, melamine resin, urea resin, phenol resin, polyurethane resin, silicone resin, alkyd resin, vinyl chloride resin, fluorine resin. , cellulose-based resins, UV curable resins, and the like can be used.

Next, a monofilament having a core-sheath structure will be described with reference to FIG.

A monofilament 1 has a core portion 2 and a sheath portion 3 . The core 2 is made of a thermoplastic resin, and the insect repellent 4 is held by the core 2 while being dispersed inside the core 2 . The sheath 3 is made of a thermoplastic resin, and is in contact with the outer surface of the core 2 to cover the core 2 . After moving from the core 2 to the sheath 3 , the insect repellent 4 is released from the outer surface of the sheath 3 to the outside of the monofilament 1 . The monofilament 1 having a core-sheath structure can improve sustained release properties.

The thermoplastic resin constituting the core 2 and the sheath 3 is not particularly limited as long as it can maintain the shapes of the core 2 and the sheath 3 and release the insect repellent 4 to the outside of the monofilament 1. Here, the thermoplastic resins forming the core portion 2 and the sheath portion 3 may be the same or different.

Examples of thermoplastic resins include polyester, polyethylene, polypropylene, polyvinyl chloride, polyethylene terephthalate, polybutylene terephthalate, polytetramethylene terephthalate, nylon, acrylic, polyvinylidene fluoride, polyethylene tetrafluoroethylene, polytetrafluoroethylene, polyvinyl Alcohol, Kevlar®, polyacrylic acid, polymethyl methacrylate, rayon, cupra, Tencel®, polynosic, acetate, triacetate.

Among these thermoplastic resins, a crystalline thermoplastic resin can be used as the thermoplastic resin forming the core portion 2 and the sheath portion 3 from the viewpoint of ensuring the strength of the core portion 2 and the sheath portion 3. . Specific examples of crystalline thermoplastic resins include polyethylene, polypropylene, polyethylene terephthalate, polybutylene terephthalate, nylon, and polyvinylidene fluoride. Among these, polyethylene, polypropylene, polyethylene terephthalate, polybutylene terephthalate, and the like are more preferable as the thermoplastic resin that facilitates melt spinning of the monofilament 1 .

A monofilament that does not have a core-sheath structure can also be made of the thermoplastic resin described above. In this embodiment, only the core 2 contains the insect repellent 4, but only the sheath 3 contains the insect repellent 4, or both the core 2 and the sheath 3 contain the insect repellent 4. You can let

In the present embodiment, the degree of crystallinity of the thermoplastic resin forming the sheath 3 can be made equal to or less than the degree of crystallinity of the thermoplastic resin forming the core 2 . The degree of crystallinity of a thermoplastic resin depends on the material of the thermoplastic resin, and the heating temperature and draw ratio when heat drawing is performed after melt spinning. Therefore, if the relationship between the degree of crystallinity, the material of the thermoplastic resin, and the heating temperature and draw ratio when heating and drawing after melt spinning is determined in advance, the degree of crystallinity of the thermoplastic resin that constitutes the sheath portion 3 can be adjusted to the core. The material of the thermoplastic resin, and the heating temperature and draw ratio for heat drawing after melt spinning can be set so that the crystallinity of the thermoplastic resin constituting the portion 2 is less than or equal to that of the thermoplastic resin.

In addition, when the heat stretching is not performed, the thermoplastic resin material is adjusted so that the crystallinity of the thermoplastic resin constituting the sheath 3 is equal to or lower than the crystallinity of the thermoplastic resin constituting the core 2. should be set. Also, the crystallinity of the thermoplastic resin forming the core 2 and the sheath 3 can be measured, for example, by a powder X-ray diffraction method. The crystallinity of the thermoplastic resin constituting the core 2 is the same as the crystallinity of the thermoplastic resin constituting the core 2 (fiber) of the single-layer structure formed under the same conditions as the conditions for forming the core 2. can be considered identical.

When the crystallinity of the thermoplastic resin forming the sheath 3 is less than or equal to the crystallinity of the thermoplastic resin forming the core 2, the insect repellent 4 is moved mainly in the amorphous portion of the sheath 3. It is possible to release the insect repellent 4 to the outside of the monofilament 1. Thereby, insect repellent performance can be demonstrated. Here, if the crystallinity of the thermoplastic resin forming the sheath 3 is higher than the crystallinity of the thermoplastic resin forming the core 2, the insect repellent 4 becomes difficult to move through the sheath 3, and the monofilament Since it becomes difficult to be discharged to the outside of 1, the insect repellent performance tends to deteriorate.

The crystallinity of the thermoplastic resin forming the core 2 is preferably 10% or more and 100% or less, more preferably 40% or more and 100% or less. The degree of crystallinity of the thermoplastic resin that constitutes the sheath 3 may be equal to or less than the degree of crystallinity of the thermoplastic resin that constitutes the core 2, and specifically, within the range of 10% or more and 100% or less. , More preferably, the crystallinity of the thermoplastic resin constituting the core 2 (10% or more and 100% or less) or less, and within the range of 40% or more and 100% or less, the heat constituting the core 2 More preferably, the degree of crystallinity (40% or more, 100% or less) of the plastic resin or less. Even more preferably, the crystallinity of the thermoplastic resin forming the sheath 3 can be 10% or more and 80% or less, and even more preferably 40% or more and 80% or less.

The weight ratio of the core 2 and the sheath 3 (core 2:sheath 3) may be 1:9 to 9:1. In this embodiment, the core 2 contains the insect repellent 4 , but the weight of the core 2 here means the weight of the core 2 excluding the insect repellent 4 . When the weight ratio of the core 2 and the sheath 3 is outside the upper limit (1:9) of the above range, the weight of the sheath 3 relative to the weight of the core 2 (in other words, the diameter of the core 2) (In other words, the thickness of the sheath portion 3) becomes too large, making it difficult to release the insect repellent 4 contained in the core portion 2 to the outside of the monofilament 1. On the other hand, if the weight ratio of the core portion 2 and the sheath portion 3 deviates from the lower limit (9:1) of the above range, the weight of the sheath portion 3 becomes too small with respect to the weight of the core portion 2, and the core The insect repellent 4 contained in the portion 2 is released excessively to the outside of the monofilament 1. - 特許庁The weight ratio of the core part 2 and the sheath part 3 is preferably 1:9 to 5:5, more preferably 2:8 to 4:6.

The insect repellent 4 held in the core 2 is not particularly limited as long as the insect repellent 4 remains on the core 2 of the monofilament 1 when the monofilament 1 is melt-spun, and can be appropriately selected by those skilled in the art. For example, a microencapsulated insect repellent 4 can be used, or the insect repellent 4 can be supported on a porous material.

In this embodiment, it is preferable to use a microencapsulated insect repellent 4 . The microencapsulated insect repellent 4 is a microcapsule filled with the insect repellent 4 as a liquid compound. When the monofilament 1 is melt-spun using a crystalline thermoplastic resin, the insect repellent 4 migrates to the amorphous part of the thermoplastic resin, and the insect repellent 4 that does not stay in the amorphous part is on the outer surface of the monofilament 1. Bleed out. As a result, tackiness (adhesiveness) is generated, making it difficult to weave, and more mothball 4 than necessary is required during melt spinning. If the microencapsulated insect repellent 4 is used, the insect repellent 4 as a liquid compound can be retained in the microcapsules during melt spinning, and migration of the insect repellent 4 to the amorphous portion of the thermoplastic resin can be suppressed. Therefore, the insect repellent 4 is less likely to bleed out to the outer surface of the monofilament 1. - 特許庁As a result, tackiness is less likely to occur, and the use of more than the required amount of insect repellent 4 can be suppressed.

Moreover, in the present embodiment, it is preferable to use the insect repellent 4 supported by an inorganic compound that controls the release of the insect repellent 4 . Examples of inorganic compounds that control the release of the insect repellent 4 include particulate, fibrous, plate-like, scale-like, and layer-like inorganic compounds. Moreover, it is more desirable that these inorganic compounds are porous substances in order to increase the surface area capable of supporting the insect repellent 4 . By using the insect repellent 4 supported by an inorganic compound that controls the release of the insect repellent 4 , the insect repellent 4 can be made difficult to bleed out to the outer surface of the monofilament 1 . As a result, it is possible to make the tackiness less likely to occur and to release the minimum amount of the insect repellent 4 necessary to exhibit the insect repellent performance.

The insect repellent 4 of this embodiment is preferably contained in the monofilament 1 as a liquid compound. By using the liquid compound insect repellent 4, the insect repellent 4 can be added to the core 2 in a stable state at a high concentration, and the diffusion rate of the insect repellent 4 inside the monofilament 1 can be easily adjusted. . Although the main component of the insect repellent 4 is not particularly limited, it is preferably liquid at room temperature. Main components of insect repellent 4 include pyrethroid insect repellents such as pyrethrin, synerin, jasmolin, allethrin, resmethrin, fenvalerate and permethrin, cyclic diene insect repellents such as toxaphene and benzoepine, malathion and fenitrothion. and carbamate insect repellents such as carbaryl, methomyl and promecarb. These insect repellents can be used singly or in combination of two or more. Among these insect repellents, pyrethroid-based insect repellents are preferable because they have excellent insect repellent performance and quick-acting properties and are less likely to exhibit acute toxicity. Moreover, among the pyrethroids, permethrin and etofenprox are preferable because they easily exhibit insect repellent performance at low concentrations and easily ensure safety for humans and animals.

In this embodiment, in the monofilament 1 having the core portion 2 and the sheath portion 3, the insect repellent 4 contained in the core portion 2 passes through the sheath portion 3 and is released to the outside of the monofilament 1. , the release of the insect repellent 4 can be adjusted. In addition, it is possible to suppress the insect repellent 4 from diffusing to the outside of the monofilament 1, thereby ensuring safety for humans and animals, and extending the duration of the insect repellent performance.

In the monofilament 1 of the present embodiment, the insect repellent 4 is contained in the core 2, and the insect repellent 4 passes through the sheath 3. Therefore, bleeding out of the insect repellent 4 on the surface of the monofilament 1 can be suppressed, and tackiness can be improved. It can be made difficult to occur. Therefore, when knitting a knitted fabric using a multifilament composed of a plurality of monofilaments 1, the knitted fabric is easy to knit.

Further, if the surface of the monofilament tends to be tacky, dust and the like tend to adhere to the surface of the monofilament. Dust or the like adhering to the surface of the monofilament is not preferable because it inhibits the release of the insect repellent from the monofilament and lowers the insect repellent performance. In addition, when the monofilament is washed (for example, washed with water) to remove dust, etc. adhering to the monofilament, the insect repellent is removed together with the dust, etc., and the release of the insect repellent from the monofilament is accelerated. is shortened.

On the other hand, in the present embodiment, as described above, bleeding out of the insect repellent 4 on the surface of the monofilament 1 can be suppressed. Inhibition of the release of the agent 4 can be suppressed. In addition, since the number of times the monofilament 1 is washed can be reduced, removal of the insect repellent 4 during washing can be suppressed, and the duration of the insect repellent performance can be extended.

A method for manufacturing the monofilament 1 can be appropriately selected by those skilled in the art, and is not particularly limited. For example, as a rational and inexpensive method of manufacturing the monofilament 1, there is a method in which the thermoplastic resin constituting the core 2 of the monofilament 1 is filled with an insect repellent 4, and the core 2 and the sheath 3 are melt-spun. be. Specifically, a masterbatch pellet is prepared in advance from pellets of a thermoplastic resin containing the liquid insect repellent 4, and the same thermoplastic resin pellets as the masterbatch pellet are mixed at a constant ratio with the masterbatch pellet. A core 2 is manufactured. Next, a monofilament 1 is manufactured using a known core-sheath spinning device using pellets of a thermoplastic resin as the sheath 3 .

Here, after the monofilament 1 is spun, it can be heated and drawn. Here, the degree of crystallinity of the thermoplastic resin, the outer diameter of the monofilament 1, and the like can be controlled by controlling the heating temperature during heating and stretching and the draw ratio of the heating and stretching.

In this embodiment, the content of the insect repellent 4 in the monofilament 1 is preferably 0.1% by mass or more and 10% by mass or less with respect to the monofilament 1 . If the content of the insect repellent 4 is less than 0.1% by mass, the insect repellent performance will be lower and the duration of the insect repellent performance will be shorter than when the content of the insect repellent 4 is 0.1% by mass or more. do. When the content of the insect repellent 4 exceeds 10% by mass, the mass of the resin of the core 2 and the sheath 3, which serve as the skeleton of the monofilament 1, is lower than when the content of the insect repellent 4 is 10% by mass or less. % decreases and the strength of the monofilament 1 decreases. Furthermore, tackiness is likely to occur, making it difficult to knit a knitted fabric. In addition, although it depends on the thickness of the sheath 3, the higher the content of the insect repellent 4, the more the insect repellent 4 is released from the surface of the monofilament 1, and the more the insect repellent 4 is ingested by humans and animals. end up The content of the insect repellent 4 in the monofilament 1 is more preferably 0.1 mass % or more and 5 mass % or less with respect to the monofilament 1 . When the content of the insect repellent 4 is 0.1% by mass or more and 5% by mass or less, tackiness is less likely to occur, and knitting becomes easier. Furthermore, the insect repellent 4 is less likely to be released excessively, making it easier to ensure safety for humans.

Moreover, the monofilament 1 and the monofilament having a monolayer structure may contain a component for imparting an arbitrary function as a functional material. Such functional materials include titanium dioxide and silica as matting agents, calcium stearate as lubricants, fine particles such as silica and alumina, hindered phenol derivatives as antioxidants, colorants such as pigments, and stabilizers. In addition to additive materials such as dispersants, there are functional materials such as ultraviolet shielding agents, near-infrared shielding agents, antibacterial agents, antifungal agents, antistatic agents, flame retardants, weathering agents, and various catalysts. When the functional material is included in the monofilament 1, the functional material may exist dispersedly in the core portion 2 together with the insect repellent 4, may exist dispersedly in the sheath portion 3, or may exist dispersedly in the sheath portion 3. It is sufficient if it adheres to the surface of the Moreover, when the functional material is included in the monofilament having a single-layer structure, the functional material may be dispersed inside the monofilament or attached to the surface of the monofilament.

Further, 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 monolayer structure. By forming minute unevenness, it becomes difficult for dust and the like floating in the air to adhere to the surface of the monofilament. Also, even if dust or the like adheres to the surface of the monofilament, the dust can be easily removed with water or the like without removing the insect repellent 4 exposed on the surface of the monofilament. For this reason, a monofilament having excellent dust resistance can be obtained.

The cross-sectional shape of the monofilament 1 and the cross-sectional shape of the single-layer monofilament can be circular, flattened, triangular, hollow, star-shaped, or other irregular shapes. Among the cross-sectional shapes described above, the cross-sectional shape of the monofilament is preferably circular from the viewpoint of abrasion resistance, posture stability, and smoothness.

Examples of the present invention will be described below.

(Example 1)
(Manufacturing of insect repellent thread)
A masterbatch pellet consisting of a highly crystalline homopolypropylene resin containing permethrin (an insect repellent) was prepared. Pellets made of highly crystalline homopolypropylene resin were prepared. The masterbatch pellets and the highly crystalline homopolypropylene resin were melted and mixed to obtain a mixture containing permethrin at a predetermined content. The obtained mixture and the prepared pellets were each melted using a melt extruder provided in the melt spinning apparatus.

The melted mixture and pellets were discharged from a core-sheath type composite fiber spinneret provided in a melt spinning apparatus, and taken up at a predetermined speed while being cooled in a water tank to obtain a monofilament with a core-sheath structure. The obtained monofilament was stretched while passing through hot water (stretching bath) heated to a predetermined temperature, and stretched to a predetermined draw ratio. The drawn monofilament was passed through a setting tank and wound on a bobbin to obtain a monofilament with a core-sheath structure in which the weight ratio of the core to the sheath (core:sheath) was 3:7. Here, the core of the monofilament is made of highly crystalline homopolypropylene (PP) resin containing permethrin, and the sheath of the monofilament is made of polyethylene terephthalate (PET) resin. This monofilament was used to produce an insect repellent yarn that was multifilament (75 denier, 24 filaments). The content of permethrin in the obtained insect repellent thread was 1% by mass.

(Manufacturing knitted fabric)
Using the obtained insect repellent yarn, a marquisette knitted fabric consisting of three yarns was produced. Here, the obtained insect repellent yarn was used as yarn C among the three yarns A to C shown in FIG. As the yarns A and B, multifilaments (75 denier, 24 filaments) composed of monofilaments having a single-layer structure were used. A monofilament with a single layer structure was manufactured using polyethylene terephthalate (PET) resin.

(Comparative example 1)
The insect-repellent yarn obtained in Example 1 was used as the three yarns forming the marquisette structure. A marquisette knitted fabric was produced using the three insect repellent yarns.

(Reference example 1)
Threads made of polyethylene terephthalate (PET) resin were used as the three threads forming the marquisette structure. These threads are multifilaments (75 denier, 24 filaments) composed of a plurality of monofilaments (single layer structure) made of PET resin. Then, a marquisette knitted fabric was produced using the three yarns described above.

(Method for evaluating insect repellent performance)
The knitted fabrics of Example 1, Comparative Example 1, and Reference Example 1 were used as insect nets, and their insect repellent performance was evaluated. The evaluation method of insect repellent performance is as follows.

A screen door frame (frame size: 43 cm × 37 cm, insect net size: 34 cm × 33 cm) equipped with each insect net was installed outdoors, and the number of insects that had stopped on each insect net for 5 seconds or longer was visually counted. Here, the insect screens of Example 1 and Reference Example 1 were arranged in the same place and left for 5 days. Also, the insect screens of Comparative Example 1 and Reference Example 1 were arranged in the same place and left for 5 days. The periods (months and days) during which the insect screens of Example 1 and Reference Example 1 are left are different from the periods (months and days) during which the insect screens of Comparative Example 1 and Reference Example 1 are left.

Insect counts were performed three times a day at fixed times (10:00, 15:00, 17:30). On each measurement day, if the total number of insects that stayed on the insect screen for 5 seconds or longer was 1 or more, the insect repellent performance was evaluated as x, and the total number of insects that stayed on the insect screen for 5 seconds or longer was 0. When , the insect repellent performance was evaluated as ◯.

(Evaluation result of insect repellent performance)
The results of measuring the number of insects are shown in FIGS. 4 and 5. FIG. 4 shows the measurement results of the insect screens of Example 1 and Reference Example 1, and FIG. 5 shows the measurement results of the insect screens of Comparative Example 1 and Reference Example 1. FIG. In each of FIGS. 4 and 5, the vertical axis represents the number of insects that remained for 5 seconds or longer (referred to as the number of insects), and the horizontal axis represents the date and time of measurement.

In Reference Example 1, the number of insects was 0 depending on the time of measurement, but the total number of insects per day was 1 or more. In Example 1 and Comparative Example 1, the number of insects was 0 on all measurement days regardless of the measurement time. From this, it was found that the insect repellent nets of Example 1 and Comparative Example 1 are excellent in insect repellent performance. Moreover, according to the evaluation method described above, the evaluation results shown in Table 1 below were obtained.

(Weather resistance evaluation method)
The insect screens of Example 1 and Comparative Example 1 were evaluated for weather resistance. As a test method for weather resistance, an insect screen was irradiated with ultraviolet rays in a laboratory under the conditions specified in JIS A1415 (2013). Before and after the weather resistance test, the tensile strength [N] and elongation [%] of the insect net were measured by a tensile test according to JIS L1096. In the weather resistance test, two assumed elapsed years (2 years and 6 years) were set by changing the UV irradiation time.

(Weather resistance evaluation results)
Regarding the insect screens of Example 1 and Comparative Example 1 before the weather resistance test, the tensile strength ratio (Example 1/Comparative Example 1) and the elongation ratio (Example 1/Comparative Example 1) are shown below. Table 2 shows. As can be seen from Table 2 below, the tensile strength of the insect screen of Example 1 was twice the tensile strength of the insect screen of Comparative Example 1. Moreover, the elongation rate of the insect screen of Example 1 was 1.3 times that of the insect screen of Comparative Example 1.

On the other hand, for Example 1 and Comparative Example 1, the strength retention rate related to the tensile strength of the insect screen and the elongation retention rate related to the elongation rate of the insect screen were calculated.

The strength retention rate is the ratio of the tensile strength of the insect screen after the weather resistance test to the tensile strength of the insect screen before the weather resistance test. If the tensile strength of the insect net does not change before and after the weather resistance test, the strength retention rate is 100[%]. On the other hand, when the tensile strength of the insect net decreases due to deterioration of the insect net over time, the strength retention rate drops below 100[%].

Elongation retention is the ratio of the elongation of the insect screen after the weather resistance test to the elongation of the insect screen before the weather resistance test. Before and after the weather resistance test, if the elongation rate of the insect screen did not change, the elongation retention rate would be 100[%]. On the other hand, when the elongation rate of the insect screen decreases due to aging deterioration of the insect screen, the elongation retention rate decreases below 100[%].

FIG. 6 shows the calculation results of the strength retention rate for Example 1 and Comparative Example 1 at two assumed elapsed years (2 years and 6 years). In FIG. 6, the vertical axis is the strength retention rate, and the horizontal axis is the assumed elapsed years. According to FIG. 6, it was found that the insect screen of Example 1 was less likely to lose its strength retention rate than the insect screen of Comparative Example 1.

In the insect screen of Comparative Example 1, when the assumed elapsed years reached 2 years, the strength retention rate drastically decreased to about 40%, but in the insect screen of Example 1, the assumed elapsed years reached 2 years. However, the strength retention rate was 80% or more. Further, when the assumed elapsed years reached 6 years, the strength retention rate of Example 1 was 67%, while the strength retention rate of Comparative Example 1 was 25%. From this, according to the insect screen of Example 1, it becomes easy to suppress the decrease in tensile strength.

FIG. 7 shows the calculation results of the retention rate of elongation for Example 1 and Comparative Example 1 at two assumed elapsed years (2 years and 6 years). In FIG. 7, the vertical axis is the elongation retention rate, and the horizontal axis is the assumed elapsed years. According to FIG. 7, it was found that the insect screen of Example 1 is less likely to lower the elongation retention rate than the insect screen of Comparative Example 1.

In the insect screen of Comparative Example 1, when the assumed elapsed years reached 2 years, the elongation retention rate was extremely reduced to about 20%, but in the insect screen of Example 1, the assumed elapsed years reached 2 years. However, the elongation retention rate was 80% or more. Further, when the assumed elapsed years reached 6 years, the elongation retention rate of Example 1 was 54%, whereas the elongation retention rate of Comparative Example 1 was 8%. For this reason, according to the insect screen of Example 1, it becomes easier to suppress the decrease in the elongation rate.

1: monofilament, 2: core, 3: sheath, 4: insect repellent

Claims (4)

In a knitted fabric consisting of multiple threads,
Among the plurality of threads, a part of the threads is a multifilament composed of a plurality of monofilaments and containing an insect repellent ,
The knitted fabric has a marquisette weave,
The knitted fabric, wherein the partial number of yarns are yarns other than chain stitch yarns in the marquisette weave . The monofilament is
a core containing the insect repellent and formed of a thermoplastic resin;
a sheath covering the core and formed of a thermoplastic resin;
The knitted fabric according to claim 1, which has a core-sheath structure. The knitted fabric according to claim 2 , wherein the weight ratio of the core part and the sheath part is 1:9 to 9:1. The knitted fabric according to any one of claims 1 to 3 , wherein the knitted fabric is used as a material for insect repellent products.

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