JPS6131228B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a polyamide monofilament net that has excellent hooking strength at a glance and does not substantially require resin processing to prevent mesh slippage, and is particularly useful for gill nets. Regarding net fabric.

Conventionally, polyamide monofilament fibers have been widely used as net fabric for fishing nets due to their excellent strength properties, transparency, and appropriate flexibility, but the knot strength properties of polyamide monofilament fibers are As a result, the knitted net fabric's instant hooking strength was not sufficient.
In addition, generally knitted nets were usually treated with resin to prevent the knots from slipping.By the way, this resin treatment certainly prevents the mesh from slipping in polyamide monofilament nets. This contributes to improving the strength of the hook at a glance, but it increases the process of manufacturing the net fabric called resin processing, which increases the cost, impairs the transparency of the resulting net fabric, and makes the net fabric more susceptible to contamination. It is said that there are many negative aspects to the above disadvantages.

Under these circumstances, various proposals have been made regarding polyamide monofilaments with high knot strength. Among them, for example, as disclosed in Japanese Patent Publication No. 54-43610, drawn nylon monofilaments have been proposed. There is a monofilament in which a monofilament is treated with a swelling agent or coated with the same or different polymer, and a layer with almost no molecular orientation is provided on the surface layer.

However, the inventors have found that nylon monofilament, which has a surface layer with almost no molecular orientation, has the problem that the knots are difficult to tighten during knitting, and the mesh tends to shift when used as a net. However, they discovered that it cannot be used in practice for nets such as gill nets, where the catch rate of fish is significantly reduced due to misalignment of the mesh. It has arrived.

That is, an object of the present invention is to provide a net fabric useful for gill nets that not only has a high net hooking strength but also has less mesh deviation or turning of the knots. To provide a polyamide monofilament net fabric which is not subjected to resin processing at all or whose resin coating amount is significantly reduced.

As described in the claims, the object of the present invention is to provide a polyamide-based monomer having a surface layer portion with an amorphous molecular orientation of about 0.5 or less and an average birefringence of about 50×10 ^-3 or more. This can be achieved by a net fabric made of filaments whose knots have a triple knot shape.

In the present invention, the degree of amorphous molecular orientation refers to the degree of amorphous molecular orientation in which a monofilament is immersed in a 0.2% aqueous solution of WHITEX-RP for 2 hours at room temperature, washed with water, and air-dried. Bunko Co., Ltd.
The relative fluorescence intensity (I
₀ ) and the relative fluorescence intensity (I ₉₀ ) in the direction perpendicular to the fiber axis of the monofilament, and this I ₀
This is the value (F) calculated from the value of I90 and _I90 using the following formula.

F=(1- _I90 / _I0 ) In addition, the average birefringence is a value measured by the compensator method of a monofilament using a polarizing microscope, and is the average birefringence including the surface layer and inner layer of the monofilament. shows.

Furthermore, the misalignment strength was measured by holding two warp threads (main threads) of the four mesh legs forming one node in the chuck of a tensile tester, and holding the remaining weft threads (bunken threads) in the chuck of a tensile tester. One of them was held in the other chuck of the tensile testing machine, and the measurement was carried out 10 times at a tensile speed of 30 cm/min.
It is the value shown as the average value, and is the value (A/B) g/d obtained by dividing the strength (A) when the weft yarn slips out of the knot by the fineness (B) of the monofilament. The larger the value, the greater the tightening of the nodule and the higher the degree of nodule fixation. In addition, the hooking strength of the net fabric refers to the value tested using the method described in 5-10-5 of JIS L-1043-1958.

The polyamide monofilament constituting the fabric of the present invention is a monofilament obtained from a known polyamide polymer, for example, nylon 6, nylon 66, nylon 610, nylon 12, etc., and has the above-mentioned degree of amorphous molecular orientation. The fiber needs to have a surface layer with a low degree of molecular orientation of 0.5 or less, and an average birefringence of at least 50×10 ⁻³ .
This kind of monofilament was produced in
As described in Publication No. 43610, it can also be manufactured by swelling agent treatment or polymer coating, but swelling agent treatment reduces the transparency and weather resistance of the monofilament, and causes loss of flexibility. Moreover, polymer coating has problems such as the surface layer becoming easy to peel off. The monofilament for gillnets according to the present invention is preferably a polyamide monofilament that is drawn, subjected to a relaxation heat treatment in saturated steam, and then subjected to a high temperature heat treatment in an inert gas or liquid to reduce molecular orientation. It is better to have a surface layer formed on the surface. More specifically, the average birefringence of the fiber after being drawn is 50×
Diameter 0.05~2 with high tensile strength of over 10 ^-3
A polyamide monofilament of 1 kg/cm ² G or more is introduced into a pressure chamber supplied with saturated steam of 1 kg/cm 2 G or more, and subjected to a relaxation heat treatment for 0.05 to 5 seconds at a drawing ratio of 0.7 to 1.0. At this stage, amorphous molecular orientation portions are formed on the surface layer of the filament. The longer this processing time,
The degree of orientation decreases. At the same time, the knot strength and average birefringence of the yarn decrease. Then, in an inert gas at 200-800℃ or a liquid at 150-265℃, a total of 0.05-5
Stretch by 1.1 to 2.5 times while passing for seconds. At the same time, the thickness of the amorphous molecular orientation layer in the surface layer was reduced to 20μ.
Adjust as below. In this way, even though the fiber as a whole has a high molecular orientation with an average birefringence of 50 × 10 ^-3 or more, the surface layer has a low degree of amorphous molecular orientation of 0.5 or less.
Special polyamide-based monofilaments applicable to the present invention can be manufactured.

In addition, the triple knot referred to in the present invention means that the warp and weft threads forming a knot, or the warp threads and the weft threads, contact and intertwine in a complicated manner, and the warp thread and the weft thread, or the warp threads, are more complex than the conventional double knot. Refers to the number of contact and crossing of each weft thread, for example, Tokoko 49
-7098, JP-A-51-82069, JP-A-52-118056,
The knot type is as described in Japanese Patent Publication No. 53-27392 and Japanese Patent Application Laid-Open No. 54-68469, and preferably the warp thread and the weft thread or the number of contact crossings of the warp thread and the weft thread is 15.
More than once is better.

Generally, the processing steps for making gill nets using monofilament yarn are as follows: knitting net → hot drawing treatment → dyeing →
There is resin processing → finishing set, and the net-making process and conditions are selected appropriately considering the properties of the yarn material used.

However, when gillnets are formed using double knots, which is commonly used as a conventional method for making nets,
In particular, since the knots tend to shift easily, resin processing is essential to prevent slippage and increase hooking strength, and the adhesion rate must also be extremely high.

In general, looking at the relationship between the resin adhesion rate, misalignment, and net hooking strength, in the case of double knots, if the resin adhesion rate is too low, misalignment will occur, and although the net hooking strength is low, the resin adhesion rate will As the amount of resin is increased, the misalignment and hooking strength are improved, and although the level is low, it can be improved to a value close to the highest value compared to the conventional level, but a satisfactory value was not achieved, and when the amount of resin was further increased. This results in a decrease in hook strength and transparency.

This phenomenon is the same even with the monofilament applied to the present invention, and in the case of double-knot knitted net fabric, it is impossible to achieve a gill net that satisfies both transparency and strength. It is something that

However, as a result of studies conducted by the present inventors, it has been found that such problems with resin and knitted mesh processing can be completely resolved and improved without any problems by combining specific fibers and specific knitted mesh processing. In other words, only when a fabric made of a specific polyamide monofilament having a surface layer with an amorphous molecular orientation degree of 0.5 or less is formed using a specific knitting process called triple knot, the resin adhesion rate is 0. Even if there is a problem, it is difficult to cause misalignment and the net hooking strength is high.Furthermore, even when a small amount of resin is attached to such a screen, there is no misalignment and the net hooking strength is the highest. It has been determined that something can be obtained. However, even in the present invention, if the resin adhesion rate is too high, it will cause a decrease in the strength of the mesh although no misalignment will occur, so the amount of resin adhesion is about 0.5wt% or less, as shown in the examples. It is preferable to

The present invention has a surface layer portion in which the degree of amorphous molecular orientation is 0.5 or less, and the average birefringence index of the entire fiber is at least
By combining a special polyamide monofilament with a diameter of 50 x 10 ^-3 or more and a fabric formed by a special knitting process called triple knot, we have created a fabric that is transparent, flexible, and highly strong for the first time. This is what we were able to achieve.

The details of the present invention will be explained below with reference to the drawings. Figure 1 shows one knot E and the net leg A that make up the net fabric.
B, C, and D are shown, A and B represent one continuous weft thread, leg B is clamped by upper chuck G, and C
and D also indicate one continuous warp thread, which is held in the lower chuck F.

Figure 2 shows the relationship between the resin adhesion rate and the leg deviation length shown in Figure 1, where a indicates the degree of amorphous molecular orientation of 0.5.
It has the following surface layer and has an average birefringence of approximately 50×10 ^-3
A net fabric made by knitting and processing a high knot strength monofilament yarn with conventional double knots, b is a fabric having a knot shear strength of 4.0 g/d or more according to the present invention.
In addition, Figure 3 shows the relationship between the resin adhesion rate and the net hooking strength (the value obtained by dividing the hooking strength by the fineness of the legs), and as in Figure 2, a' shows the relationship between the resin adhesion rate and the netting strength (the value obtained by dividing the hooking strength by the fineness of the legs). Net fabric b' indicates a net fabric obtained by knitting and netting with the triple knots of the present invention.

With conventional double knots, when the resin adhesion rate is low, that is, when the resin adhesion rate is C or less in Figures 2 and 3, the mesh is sampled as shown in Figure 1 and the sample is chucked. After installation, when the chuck F is moved downward and a displacement test is performed, point H on leg A shifts downward and point I on leg B shifts upward.
In this case, as shown in FIG. 2, the length of deviation becomes large, and as shown in FIG. 3, the net hooking strength is low, which is not desirable as a gill net. In addition, the resin adhesion rate is C
As the number increases further to d in Figures 2 and 3, as shown in Figure 2, even with the conventional double-knot net fabric a, the leg deviation length becomes considerably small, and in that case, the net hooking strength of a' has the highest value at point f. If the resin adhesion rate is further increased to e, the displacement length becomes 0 and the legs do not displace, but instead, the third
As seen in the figure, the net hooking strength decreases as seen in a' at the resin adhesion rate of e. On the other hand, for b' with a misalignment strength of 4.0 g/d or more, even if the resin adhesion rate is 0%, the deviation length is small, and the resin adhesion rate is 0%.
The hooking strength of the net fabric also showed almost the maximum value f′ when the method of the present invention was used, and even though no resin was attached, the length of leg deviation was small and the hooking strength of the net fabric was almost at the maximum value. It shows something.

Also, Figure 4 shows an example of a tribble knot,
A' and B' indicate one continuous weft thread, C' and D' indicate one continuous warp thread, and g to w indicate the contact between the warp thread and the weft thread, or the warp thread and the weft thread, respectively. Indicates a point of intersection. Next, the present invention will be explained in more detail with reference to Examples.

Example 1 A nine-six monofilament yarn melt-spun in a conventional manner was drawn in warm water at 90°C, and then subjected to pressure
In order to treat the monofilament in saturated steam of 3.0 kg/cm ² , it passed through a steam treatment tube in a relaxed state to remove moisture adhering to the surface of the monofilament, and then passed through a dry heating furnace at 400°C while being stretched 1.59 times. A high knot strength monofilament having an average birefringence of 54×10 ⁻³ , a degree of amorphous molecular orientation of 0.22, and a wet knot strength of 6.5 g/d was obtained by applying oil in a conventional manner. This monofilament yarn was knitted by the method described in JP-A No. 52-118056, and then heat-stretched and tightened with steam at 100°C for 7% stretching for 3 minutes, then dyed at 85°C for 60 minutes and air-dried. rear,
Steam the stretched mesh to 0.98 of the mesh size when knitting.
Finish setting was carried out for 3 minutes at 120°C to obtain a net fabric as a final product. When this fabric was measured using the method described above, the slippage strength was 5.0g/d, and the fabric hooking strength was
It was 8.3 g/d, and a high-strength mesh fabric with no misalignment was obtained. Under the same conditions, heat-stretched, dyed, and resin processed using Nylofix S50 manufactured by Ota Kaken Co., Ltd.
The double-knot mesh fabric was processed for 20 hours to have an adhesion rate of 0.5%, and then stretched with steam at 120°C for 3 minutes to a knit mesh ratio of 0.98. The hooking strength was 6.9 g/d.

Example 2 The monofilament yarn obtained in Example 1 with an average birefringence of 54×10 ^{-3 and} a degree of amorphous molecular orientation of 0.22 and a wet knot strength of 6.5 g/d was knitted by the method of JP-A-52-118056. This net fabric was stretched by 3% and placed in steam at 100℃.
After tightening for 1 minute, dyeing at 85℃ for 60 minutes, air drying, and stretching to a mesh size of 0.98 of the knitted mesh.
Finish setting in 120℃ steam for 3 minutes,
Furthermore, rosin resin nylon fixings S50-20H
(manufactured by Ohta Kaken) was dipped in a 0.5% aqueous solution to obtain a net fabric with a resin adhesion rate of 0.1% after drying. This mesh fabric had a shear strength of 5.2 g/d and was cut without any shear, and a hooking strength of 8.6 g/d.

With conventional double knots, the mesh fabric that was tightened, dyed, finished set, and treated with resin under the same conditions had a shear strength of 1.2 g/d and a net hooking strength of 5.0 g/d.

[Brief explanation of the drawing]

Figure 1 shows an enlarged view of the nodule. Figure 2 is a diagram showing the relationship between resin adhesion rate and leg deviation, Figure 3 is a diagram showing the relationship between resin adhesion rate and mesh hooking strength, and Figure 4 is a plan view showing an example of a triple knot. Yes, A, B, A', B' are weft yarns, C, D, C'D' are warp yarns, a, a' are double knot net fabrics, b, b' are tribble knot net fabrics, c, d , e are resin adhesion rates, f and f' are maximum hooking strengths, and g to w are triple knot contact and intersection points.

Claims (1)

[Claims] 1. has a surface layer portion with an amorphous molecular orientation degree of 0.5 or less,
A polyamide monofilament net fabric comprising a polyamide monofilament having an average birefringence of at least about 50×10 ^-3 and having a triple knot shape. 2. The polyamide monofilament net fabric according to claim 1, wherein the knot shear strength is at least 4.0 g/d or more.