JPS62184163A - Fishing net and its production - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a fishing net made of synthetic resin monofilament and a method for manufacturing the same. It concerns the manufacturing method.

[Prior art and its problems]

Gill nets, which catch fish by hooking them into the line, have excellent transparency, making it difficult for fish to see the net, high net strength (having a moderate elongation, making the net difficult to tear during fishing, and It is desirable that nets have excellent flexibility and are easy for fish to get stuck or become entangled in the water, are easy to handle on board, and do not bulk up when loaded onto a ship. There is.

Conventionally, synthetic resin monofilament has been used as the main material for gillnets because it has excellent transparency and the strength of the raw thread is high. However, monofilaments have the disadvantage of being stiffer than multifilaments.

Furthermore, although multifilament is flexible and has high fiber strength, it has been pointed out that it is significantly inferior to monofilament in terms of transparency. For this reason, in recent years, monostrand yarns (single thick denier multifilament yarns or fine denier monofilament bundled yarns) that have both the transparency of monofilament and the flexibility of multifilament have been developed.
Gillnets have also been developed, but at present they do not have sufficient properties.

In addition, studies have been conducted on manufacturing methods to obtain transparent, highly strong, and flexible net fabrics, and improvements in elasticity have been seen.

However, with the conventional methods, it has not been possible to obtain a highly strong and flexible net fabric with satisfactory properties.

The reason for this is that increasing the strength of yarn with the same fineness increases the Young's modulus and sacrificing flexibility; on the other hand, fabrics made from flexible yarns have a low strength utilization rate. This is because it has a fundamental drawback that it cannot achieve high strength.

[Purpose of the invention]

The purpose of the present invention is to improve the drawbacks of conventional fishing nets, especially gill nets, and to provide transparent, highly strong, and flexible fishing nets.
The purpose of this invention is to provide a fishing net that is durable, has excellent catchability, and is easy to handle.

[Structure of the invention]

To achieve the above object, the fishing net of the present invention is characterized in that, in a net fabric made of synthetic resin monofilament, the melting point of the net leg portion of the net fabric is lower than the melting point of the knot portion (both are 2°C higher). The manufacturing method is characterized by applying a heat-inhibiting agent to the knotted portions of a synthetic resin monofilament net, and then steaming and setting the net.

Conventionally, the weak point of fishing nets made of synthetic resin, mainly synthetic fibers, has been a decrease in the strength of the knots. This is because, although the strength of the legs of the fishing net increases when it is set with steam during manufacturing, the knots also become highly crystallized by the steam, making them hard and stiff. In the present invention, when setting with steam, a heat inhibitor mainly made of resin is attached to the knots of the fishing net in the form of a film or knots, and this heat preventer prevents the knots from heating, thereby preventing the knots from heating. Improved the strength loss of the parts.

As the material for the synthetic resin monofilament used in the present invention, nylon, polyester, polybutylene terephthalate, polypropylene, polyvinylidene chloride, polyvinyl alcohol, etc. can be used, but nylon is the most preferred in terms of transparency, strength, and flexibility. preferable. Preferred nylons are nylon 6 and nylon 66, which may be homopolymers or copolymers of nylon 6 and 66. Of course, other nylon may also be used.

The structure of the fishing net according to the present invention is not particularly limited, but may include knots and net legs knitted from conventionally known frog knots, double or double frog knots, and various other multiple frog knots. Preferably, it is composed of:

In particular, it is more preferable to have a net structure suitable for use in gillnets.

In other words, it is preferable to use a net fabric with a structure that minimizes the displacement of knots as much as possible, which makes it easier to obtain a highly strong net fabric.

In such general net fabrics, various tensions are applied during normal use, and as a result, the net may break, and most of the broken areas are knots. It is thought that this is because when force is applied to the knot, lateral pressure is applied to the threads inside the knot, causing stress concentration, which causes the knot to break before the web leg. For this reason, when manufacturing the net fabric, the knots are tightened by stretching heat treatment or treated with resin to fix the knots so that they do not shift.

By changing the temperature, stretching (or relaxation) rate, etc. during this stretching heat treatment, the physical properties of the net fabric, particularly the strength and elongation degree and flexibility, can be significantly changed. In other words, when stretched at high temperatures, crystallization,
As the orientation progresses, the legs become thinner and more flexible, and the strength of the net leg portions increases, but the nodules also become brittle as the crystallization progresses due to heat. As mentioned above, the mesh is cut from the knots, so if the mesh is heat-treated at high temperatures and the knots are crystallized, the mesh will be weaker.

Additionally, when net fabric is relaxed and set in high-pressure steam, the moisture in the steam acts as a plasticizer, making nylon soft. However, the high temperature steam setting weakens the knots in the same manner as described above.

As a result of intensive investigation into this problem, the inventor of the present invention processed the knots of the mesh fabric with resin and covered it with a resin that has excellent heat and water resistance.
The legs of the net were heat set at a high temperature using high pressure steam or the like without being coated with resin. The nodules are coated with a heat-resistant and water-resistant resin, so they are not directly affected by heat and moisture. Therefore, the nodules do not crystallize, so the strength decreases even after heat setting. There isn't.

Furthermore, after resin-processing the knots, the net fabric is subjected to high-temperature heat treatment.
If the heat conditions of the normal finishing set are applied again to high-stretching, the warp and weft yarns that make up the knots will be aligned, and the knots will also be tightened, resulting in high strength. It becomes more flexible due to its narrower diameter.

The net fabric of the present invention thus obtained has different characteristics between the knot portion and the net leg portion. The knots of the net fabric are not straight and have large curves, and their length is extremely short, so it is difficult to use them for physical property tests. There are clear differences in properties between the nodule and the net leg, especially in terms of specific gravity and melting point. There is a proportional relationship between specific gravity and melting point, and the higher the specific gravity of the same material, the more crystallized it will be, and therefore the higher the melting point.In the present invention, the difference between the nodule and the net leg is particularly important in terms of melting point. It has been found that net fabrics with a temperature of 2°C or higher have excellent physical properties such as strength and flexibility.

In other words, the melting point of the knots is lower than that of the net legs, which are affected by heat and moisture, because they are completely covered with resin and are not affected by direct heat or moisture during steam setting. If the difference in melting point is 2°C or more, there is no decrease in the strength of the fabric due to heat setting, and it becomes flexible, especially when relaxed set. If the difference in melting point between the knots and the net legs is less than 2°C, the difference in the effect of heat received during heat treatment between the knots and the net legs is small, and only a less strong or stiff net fabric can be obtained. do not have. Furthermore, even if the difference in melting point between the nodule and the net leg is 2°C or more, the melting point of the nodule is 225°C or more.
If the temperature exceeds ℃, the crystallization of the nodules will progress too much and the strength will be weak (unfavorable).

In other words, in a preferred embodiment of the present invention, in the knots and the net legs constituting the net fabric, the difference between the melting point A of the knots and the melting point B of the net legs is B-A≧2°C, and A≦225℃
It can be said that it satisfies the following.

The melting point here refers to the effect of oxygen in the air using a commonly used differential thermal measurement device after removing the adhered resin etc. with a solvent, water, etc. that does not affect the properties of the material. The melting point at the peak of the endothermic curve (melting point at the end of melting) was determined. The melting point at the end of melting is approximately 10° C. higher than the melting point at the start of melting for each sample, but the melting point at the end of melting is easier and more convenient to measure even when the amount of sample is small. Further, the knotted portion was defined as a portion where warp threads and weft threads or each thread overlapped.

In order to have a melting point difference between the net legs and the nodules as in the present invention, it is necessary to apply a heat-inhibiting agent to the nodules in advance. It is fine as long as it can cause a difference in melting point in the process of 0.
For example, when treating fabric with chemicals, it is sufficient to use a treatment agent that is not affected by the chemicals, and when using only heat setting, it is necessary to control only the conditions without attaching resin in advance. But it is possible.

As the resin to be applied to the nodule, for example, acrylic resin, epoxy resin, phenol resin, rosin resin, etc. are preferable, and each resin may be used alone, but a mixture of two or more resins may be used. May be used. As for the method of coating only the nodules, the commonly used spot processing method, which takes advantage of the difference between the thickness of the nodules and the thickness of the net legs, is faster and more uniform. However, other methods are also possible. Also,
Originally, it is preferable for the properties to be attached only to the nodule, but it is acceptable if some amount is attached to the net leg part near the nodule.

In addition, it is preferable that the resin adhesion rate is high, but if it is too low, it will not be possible to sufficiently cover the nodules from the effects of heat and moisture during heat setting with saturated steam, and the strength of the net fabric after heat setting will decrease. Only weak netting will be obtained.

Although it varies depending on the characteristics of the resin, particularly heat resistance, water resistance, adhesiveness, etc., a deposition rate of at least 1.0% or more, preferably 2% or more is preferred.

In the resin processing of the present invention, after the knitted fabric is vertically set (continuously set in the direction of the knitted mesh), the knots may be resin-processed, but it is easier to perform resin processing while vertically setting. This method is convenient, reduces uneven adhesion of the resin, and can be completed in one step, including the drying process, which is preferable.

The net fabric with resin applied to the knots dries and undergoes the traditional dyeing process, then the stitches are picked up and dyed in the horizontal direction (opposite to the direction of the knitted net).
and attach it to the shrinkage treatment machine in an unstretched state so that the eye can be maintained at a constant length, that is, after the dyeing process, or in a relaxed state so that the eye after shrinking is smaller than after dyeing. Also, the material is subjected to heat treatment in a free state.

The shrinkage treatment may be performed using any commonly used high-pressure steamer 1 or thread steamer that can set raw steam under pressure.

In particular, from the standpoint of relaxing setting, etc., a high-pressure steamer whose setting length can be freely changed within the can is preferable. The temperature varies depending on the characteristics of the yarn used, such as its diameter and whether it is a homopolymer or a copolymer, but 125
The optimum temperature is appropriately selected from the range of 140°C to 140°C. That is, if the temperature is lower than 125°C, the net legs will not have flexibility, whereas if the temperature is higher than 140°C, the net legs will devitrify and lose transparency.

In addition, if the temperature rises further, the net legs become molten and the net fabric strength cannot be obtained.

The heat treatment time is appropriately selected in the range of 3 to 20 minutes depending on the temperature.

The net fabric that has been subjected to shrinkage setting may be left as is, or it may be further subjected to stretch setting using a conventional method. The higher the stretching ratio at the time of stretching finishing setting, the thinner the net legs after stretching and the more flexible the net fabric, which is preferable.
If it exceeds 1.10 times the 4th stitch, the rate of cutting of the mesh will increase, so it is preferably 1.10 times or less.

The higher the heat treatment temperature during finishing setting, the better the setting properties of the net fabric, but the above-mentioned problems such as devitrification and melting occur, so the temperature is set at 140°C.
It is necessary to do the following. Further, the usual time for finishing setting is about 3 to 5 minutes.

〔Effect of the invention〕

As mentioned above, since the knots of the net fabric obtained according to the present invention are coated with resin in advance, even those finished with only a high-temperature steam set can block the effects of heat and moisture, and the strength of the knots will not deteriorate. The result is a fabric that is as strong and flexible as ever.

Furthermore, since resin processing is applied only to the knots, the transparency of the net leg portions is not impaired by the resin, and a net fabric with excellent transparency can be obtained. Therefore, the fishing net obtained from the above-mentioned net fabric can be made to withstand long-term use, to be small in bulk, and to be excellent in handling workability and fishing performance.

〔Example〕

Example 1 Nylon yarns of sizes 3 and 5 (770 denier), which had a copolymerization ratio of nylon 6 and 66 of 95:5 and were spun using a normal spinning and drawing method, were knitted with double frog knots to obtain a net. The resulting net fabric was processed with resin only at the knots using a regular spot resin processing machine. The resin used is UN-81 (Dainippon Ink ■, acrylic resin), processed with a solid content of 20%, and dried with dry heat at 13
After processing at 0°C for 20 seconds at a stretching rate of 3%, the nodules were re-processed with resin using Nylofix 550-20H (rosin resin) manufactured by Ota Kaken ■ with a solid content of 20%, and dried under the same drying conditions as before. did. Steam this net fabric using a thread steamer at a temperature of 13
A treatment was carried out for 5 minutes at 5° C. to obtain the net fabrics shown in Table 1.

Example 2 The net fabric obtained in Example 1 was further dyed using a regular dyeing machine at a temperature of 85°C for 30 minutes, air-dried for 12 hours or more, and then stretched to the knitted mesh bar at a steam temperature of 120°C for 3 minutes. Batch setting was performed to obtain the net fabrics shown in Table 1.

Comparative Example 1゜ The fabric after knitting used in Example 1 was heated to 90°C and set in the knitting direction (vertical direction) at a constant length for 3 minutes, and after air drying for 12 hours or more, it was set in the knitting direction (vertical direction) using a horizontal intermediate machine. The film was stretched by 3% in the opposite direction, heat-set at 95° C. for 3 minutes, air-dried again, and dyed under the same conditions as in Example 2, followed by air-drying. Furthermore, Ota Kaken■
The sample was immersed for 3 minutes in a 1% solids solution of Nylon Fix 350-20H manufactured by Co., Ltd., followed by centrifugal dehydration and air drying again. Steam this fabric using a steam setter at a temperature of 1
Stretch it at 20℃ for 3 minutes to 0.98 of Akebono mesh metal.
The front mesh fabric was obtained.

The fabric strength and elongation listed in Table 1 and Table 2 below are JI
It was measured by the method described in SL-1043-5-10-5 (b). The measuring device is Shimadzu Autograph 5D1.
00 was used, and the tensile rate was measured at 30 (Jl/min).

In addition, flexibility was determined by placing a trial sample from three countries with the net legs cut off with scissors on the center of a chrome-plated iron ring with a ring diameter of 11. When the sample is pushed in, the resistance applied to the presser bar is detected by a load cell and read from the chart of the tensile tester. The larger the number, the greater the resistance to pushing the sample. In other words, this indicates that the sample is stiff. Melting point measurements were made by cutting out the nodules and net legs of each sample with scissors, washing them in xylene solution to remove the attached resin, and air-drying them for over 12 hours. The temperature at the end of melting at the peak of the endothermic curve was measured using a differential thermogravimetry simultaneous measuring device, 5SC1560GH (TO/DTA).

As shown in Table 1, Examples 1 and 2 have a difference in melting point between the knot part and the net leg part of 3°C or more, indicating that they are stronger and more flexible than Comparative Example 1.

(Margins below this page) Table 1 Example 3 Monofilament yarn No. 6 (1320 denier) with a copolymerization ratio of nylon 6 and nylon 66 of 95:5 and obtained by ordinary spinning and drawing methods was used. The net fabric obtained by knitting with Yuri 155 Dragon at the nodules of the heavy frog is subjected to vertical heat treatment for 3 minutes at a temperature of 90°C, and after air drying for over 12 hours, the nodules are knitted with a regular spot resin processing machine. , acrylic resin UN-8
1 (manufactured by Dainippon Ink ■) with a solid content of 20% and dried at 130°C for 20 seconds.
It was reprocessed with 0% liquid and dried. The resin adhesion rate of this net fabric was 2.55%. This net fabric was heat-treated with high pressure steam at 130℃ for 5 minutes in a free state using a thread steamer.
The net fabric shown in the table was obtained.

Example 4 After air-drying the net fabric used in Example 3 after setting the length using moist heat, it was treated with a 30% solids solution of Sumikaflex 751 (ethylene vinyl acetate resin) manufactured by Sumitomo Chemical Co., Ltd. using a spot resin processing machine. After processing with resin, dry heat at 130℃ for 20
The resin adhesion rate of the screen fabric dried for seconds was 3.1%. This fabric was heat-treated with high-pressure steam at 125°C for 5 minutes in a free state using a thread steamer, and then heated using a high-pressure steam setter for 1
The knitted fabrics were set at 20° C. for 3 minutes in a state where they were stretched to a lily shape to obtain the net fabrics shown in Table 2.

Comparative Example 2 The net fabric used in Example 3.4 after the wet heat vertical stretching was stretched at 95°C for 3 minutes at a stretching ratio of 3 as in the normal process.
% (159.6 m mesh) and air-dried, then immersed in a 1% solids solution of Nylon Fix 350-20H manufactured by Ota Kaken ■ for 3 minutes, centrifugally dehydrated, and air-dried.

The resin adhesion rate of this net fabric was 0.28%. This net fabric was heated to 120℃ for 3 minutes using a high-pressure steam setter at 152W.
Finish setting was performed according to the grain, and the net fabric shown in Table 1 was obtained.

As shown in Table 2, it can be seen that the fabric of Example 3.4 of the present invention is stronger and more flexible than that of Comparative Example 2.

(Margins below this page) Table 2

Claims (1)

[Claims] 1. In a net fabric made of synthetic resin monofilament,
The melting point of the net legs of the net fabric is at least 2 times higher than the melting point of the knots.
A fishing net characterized by high temperature. 2. The fishing net according to claim 1, wherein the synthetic resin is nylon. 3. A method for manufacturing a fishing net, which comprises applying a heat-preventing resin to the knots of a net made of synthetic resin monofilament, and then steaming and setting the net. 4. The method for producing a fishing net according to claim 3, in which the steaming treatment is performed at 125° C. or higher. 5. The method for manufacturing a fishing net according to claim 3, wherein the synthetic resin is nylon.