JPH0345766A - Polyester net for ground and preparation thereof - Google Patents

Abstract

PURPOSE:To prepare the subject net having a light weight and a high strength by knitting polyester fibers having a specific strength and an elongation into a warp-knitted net. CONSTITUTION:Polyester fibers having a tensile strength of >=8.3g/D, an breaking elongation of 14-20% and an intermediate elongation of >=5.5% at least 4.5g/D are subjected to a warp knitted net-preparing process to provide the objective net. The fibers are preferably knitted into a net in which the ratio between the front and back yarn lengths of the warp-knitted net is 27-32% and the loop number of the raw yarns between the net legs is 11-15 loops/inch.

Description

DETAILED DESCRIPTION OF THE INVENTION FIELD OF INDUSTRIAL APPLICATION The present invention relates to a polyester land net mainly used as a safety net and a method for manufacturing the same.

``Conventional technologyj'' Terrestrial nets such as safety nets have traditionally been made of frogmata knotted nets,
Knotless mesh etc. are used. The fibers used include various synthetic fibers such as vinylon, nylon, polyester, polyethylene, and polypropylene. In recent years, many safety nets have been used to prevent falls, but in addition to being able to withstand the impact force of falling people, these nets also have small mesh sizes to prevent small objects such as bolts from falling through them. was commonly required.

However, when it comes to making a strong net with a small mesh, a large amount of raw yarn is inevitably used, and in particular, the Kajimata knotted net has the disadvantages that it is difficult to be strong and is also heavy, so the amount used has decreased.

In addition, in the case of a penetrating knotless mesh, if the mesh size is small, the knitting efficiency will be poor and there is a limit to the hanging width. For this reason, knotless networks have been unable to adequately meet the needs of consumers. Therefore, safety nets are now made of polyamide fiber (nylon).
Demand for Russell nets using

Among synthetic fibers, polyester &! Ii fibers, mainly polyethylene terephthalate fibers, have the characteristics required for land-use nets, such as good light resistance and good dimensional stability. In this case, there was a problem that the net strength was difficult to produce, and the amount used was small.

That is, polyester fibers have the advantage that they do not become yellow, especially when exposed to sunlight, and nylon tends to yellow. Also, polyester fiber has an official moisture content of 0.5
% [4.5% for nylon], it absorbs water easily, dries easily, does not stretch or shrink even when wet, and has good dimensional stability.

On the other hand, nylon stretches when wet, so even if the net is properly fixed, it has the disadvantage that the net becomes loose when wet.

The following table shows comparative examples of the tensile strength, etc. of polyamide fibers and polyester fibers when made into raw threads and nets.

Table 1 As can be seen from the table above, polyester fibers have a tensile strength of only 1.2% compared to polyamide fibers.
However, when it becomes a vertically knitted net, it becomes 8% lower.

Furthermore, if the net is designed to have the same strength, it is necessary to increase the basis weight by at least 8%, and considering the specific gravity of polyamide fiber, polyester fiber is approximately 30% heavier overall than polyamide fiber. There was a drawback.

``Problems to be Solved by the Invention'' The present invention solves the problem of weight loss when trying to obtain a specified strength that occurs when a land net is manufactured using polyester fibers (hereinafter simply referred to as r-polyester fibers). This was done to eliminate the drawback of becoming heavy.

In other words, the physical properties of the polyester fiber used are adjusted so that it is suitable for the characteristics of a vertically knitted net for land use.
The above-mentioned drawbacks are solved by achieving an optimal balance between the front yarn and the back yarn under the t condition.

The present invention has a tensile strength of 8.3 g/D or more and a cutting elongation of 14%.
This is a polyester track and field net characterized in that it is warp-knitted using polyester fibers having an intermediate elongation of at least 4.5 g/D and 5.5% or more.

In addition, when making a net using polyester fibers having the above-mentioned physical properties, the yarn length ratio of the front yarn and back yarn of the warp knitting net is in the range of 27% to 32%, and the number of raw yarn loops between the legs is 1. This is a polyester track and field net knitted in a range of 11 to 151 threads per inch.

Furthermore, the shape formed by knitting is hexagonal, tortoise shell shape,
This is a polyester land net characterized by a large number of intersections with the net legs.

In addition, the above polyester track and field net has flame retardant properties,
This is a polyester land net that has been given H flammability.

"Function J When spinning and drawing polyester fibers, generally when the draw ratio is increased, the tensile strength increases, but the elongation decreases. If the draw ratio is lowered to increase the elongation, the tensile strength decreases. By using the polyester fiber of the present invention, which has a tensile strength of 8.3 g/D or more and a breaking elongation in the range of 14% to 20%, the draw ratio and tensile strength can be adjusted in a well-balanced manner, making it easier to knit. It is decided to use raw yarn with a balanced thread, and if the net yarn strength of the net to be knitted is 52 authentic, it will work so that it can be larger than 49, which is a value for boat fishing. It's hard to get strong.

Moreover, since the intermediate elongation is 5.5% or more, it acts so as to be able to sufficiently follow the high-speed behavior of the needles in a warp knitting machine.

In addition, the yarn length ratio of back yarn and front yarn was in the range of 27 to 32%, and the number of loops constituting the legs of the net was within the range of 11 to 15 per inch length of one leg of the net, which was relatively stable. , the required tension of the net is 49%, which is the required tension of a general net.

If the number of loops is below this range, the net structure will become loose and it will not be possible to maintain strength, and if it exceeds this range, the mesh will be too congested and the net will become hard, making it impossible to obtain the required tension of the net. do not have.

In addition, in hexagonal and tortoiseshell shapes, the width of the intersection is long, so the strength increases by about 60% compared to the shape in which the knitting yarns are connected at points.

“Example J First, the invention according to claim 1 will be explained in detail.

Table 2 shows the relationship between tensile strength and elongation of polyester fibers.

Table 2 As can be seen from A and E in this table, it was not possible to increase the strength of the net by simply increasing the tensile strength of the yarn, and it was found that elongation plays an important role. That is, the elongation is also required to be at least 14%. Regarding the upper limit, 2.
An elongation of 0% or less is required.

Furthermore, the experimental results show that the tensile strength of the yarn is at least 8
．． 3 g/D or more was good.

Further, the intermediate elongation of the yarn that follows the high-speed behavior of the needle in warp knitting must be 5.5% or more.

Next, the knitting conditions using the warp knitting machine using the polyester fiber of the invention according to claim 2 will be described.

When knitting with a knitting machine, the present inventor found that the yarn length balance between the front yarn and back yarn in the knitting structure and the number of loops in the legs greatly influence the strength of the net yarn.

FIG. 1(a) shows the outer shape of the net, and FIG. 1(bl) shows an example of its knitting structure.

In this figure, l in the knitting structure represents the front yarn, and 2 represents the back yarn. The back yarn 2 is intertwined with the front yarn to give weft strength, but the balance is usually determined by adjusting the beam brake on the knitting machine.

However, when analyzing the balance, we actually analyzed the network structure, divided the raw yarn into front yarn 1 and back yarn 2, measured the yarn length, expressed it as the ratio of back yarn length / front yarn length, and calculated the back yarn length / The results of measuring the relationship between front yarn length and net strength are shown in the second
As shown in the figure.

The netting used to measure the above relationship was made by making 52 full nets.

According to this result, the ratio of back yarn to front yarn is 30.
A peak is seen at ~31%, which is the best. However, since there are variations in measurements, it has been found that it is best to knit with a balance in the range of at least 27% to 32% of the ratio based on 49 pupils, which is the tension required for general nets.

An additional note is made regarding the 52 full-scale network.

The front yarn is constructed by creating a loop in which one yarn connects, so in order to reinforce the front yarn (in the form of a crossed original yarn), there is a relationship of 3Y (front) + 2X (back), and in the case of polyester fiber Since it is one piece of 250 denier yarn, both the front and back are 250 denier.
If you use denier, you can get at least 5 authentic net fabrics. Therefore, as an example of 52 full-scale net, it is possible to knit the front yarn with 3000 denier and the back yarn with 2000 denier.

FIG. 3 shows the results of measuring the relationship between the number of loops (number of front loops) constituting the legs of the net and the force.

From this result, the number of loops is 11 per inch length of one net leg.
When the net was within the range of 15, it was able to maintain a relatively stable net tension of 49 kg or more, which is the required tension of the net. Below this range, the structure will become loose and it will not be possible to maintain strength, and above this range, the structure will be too congested and the net will become hard, making it difficult to produce strength.

It has been found that the balance between the front and back of the raw yarn constructed in this way and the number of hits to the legs are important factors for the strong retention of the net, and this relationship becomes clear from 52 Honkaku. 60 has passed through the most serious nets.

Next, we will discuss the relationship between the size of the intersection of the legs of the net and the strength. The first image is the external view of the net when it is spread out horizontally.
In the figure, A is the crossing length of the net, and B is the length when the net is pulled in the vertical direction. The net shape resulting from changing the size of the crossing length is shown in Figure 4 (al (bl (C
Shown in 1.

In FIG. 4 (83), its shape is approximately rhombic.

In this case, the ratio of the intersection A to the vertical eye B is 0%, and the vigorous force is as small as 0.62 kg/1 full force.

Figure 4 (In BL, the intersection is slightly longer than in the above fat,
In this example, the ratio of intersection A to vertical stitch B is 4.9%.

At this time, the strength was 0.96kg/1 full-scale (54% more strength than AT).

In the example of FIG. 4(C), the ratio of intersection A to vertical stitch B is 9.
This example shows an example in which the phase strength is 1.2%.
0 kg/1 full-scale, and the strength of the tongue has improved by 1% compared to fa).

The above relationship is shown in FIG.

According to this figure, the strength is constant in the area where the ratio of the intersection A to the vertical eye B is 10% or more. That is, the net shape based on this ratio is a hexagonal shape and a tortoiseshell shape.

Note that the polyester track and field net shown in this example can be made into the desired high-strength net as long as it has the above-mentioned yarn performance and knitting conditions, and it may be dyed later.
Alternatively, it may be manufactured using undiluted colored yarn.

Furthermore, when it comes to flame-retardant and flame-retardant finishing for use on land and safety nets, even if processed with normal finishing agents,
It was found that there was almost no decrease in strength. For example, phosphate esters, halogenated phosphate esters, halogen compounds, etc.
No phosphorus-containing polyol! No particular problem occurred with any of the formulations such as a-products.

Effects of the Invention 1 Conventional vertically knitted land nets made of polyester fibers are
Due to the need to increase the total number of yarns used to achieve strong strength, they were heavy and difficult to handle in practical use, but when knitted based on the raw yarn performance and knitting conditions of the present invention, they are lightweight and It has excellent effects such as being able to provide a land net with high strength.

[Brief explanation of drawings]

Figure 1 (al is an external view of the net manufactured by vertical knitting, Figure F
Figure 2 is an explanatory diagram showing the relationship between back thread length/front thread length and force, and Figure 3 is an enlarged organizational diagram of the intersection of the same net. An explanatory diagram showing the relationship between the number of loops constituting 1 m and the strength, Figure 4 fal, (b) and (C) are external views of nets manufactured by changing the length of the intersection part by vertical knitting,
FIG. 5 is an explanation X showing the relationship between the ratio of the intersection A and the vertical mesh B of the mesh and the force. l is the front thread, 2 is the back thread

Claims (5)

[Claims] (1) Using polyester fibers having a tensile strength of 8.3 g/D or more, a breaking elongation in the range of 14% to 20%, and an intermediate elongation of at least 4.5 g/D of 5.5% or more. A polyester track and field net characterized by a vertically knitted net. (2) A method for producing a polyester track and field net, which is produced by vertically knitting a polyester fiber having the physical properties described in claim 1. (3) A polyester fiber having the physical properties described in claim 1, in which the yarn length ratio of the front yarn and back yarn of the warp knitting net is in the range of 27% to 32%, and the number of raw yarn loops between the legs is in the range of 27% to 32%. A polyester track and field net characterized by being knitted with 11 to 15 pieces per inch. (4) The polyester land net according to Claims 1 and 3, characterized in that the knitted shape is hexagonal or tortoise-shell shaped, and the number of intersections with the net legs is increased. (5) A polyester track and field net according to any one of claims 1, 3 and 4, characterized in that the polyester track and field net is imparted with flameproofing and flame retardant properties.