JP2003055835A - Polyester fiber for tent base fabric and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polyester fiber for tent base fabrics having cotton-like aesthetic sense and excellent gloss and having small single yarn fineness and slight scattering of strength and to provide a method for efficiently producing the fiber. SOLUTION: This polyester fiber for tent base fabric comprises a polyester fiber having properties of 1.8-4.5 dtex single yarn fineness, <=1,000 dtex total fineness, >=6.0 cN/dtex strength, and <=1.0 Uster unevenness (U%). In this method for producing the polyester fiber for tent base fabrics, pressure applied to the rear face of a spinneret discharge hole is kept to 5.8-12 MPa and a spinning draft which is a ratio of discharge linear velocity to take-off roller is kept to <=110 in a step for carrying out melt spinning of a polyester having 0.7-1.3 intrinsic viscosity and a stretching the spun polyester.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyester fiber for a tent base cloth, which has a luster excellent in appearance like cotton, a small single yarn fineness and a small variation in strength, and an efficient production method thereof. is there.

[0002]

2. Description of the Related Art Conventionally, vinylon fibers, polyamide fibers, polyester fibers, etc. have been used as materials for tent base cloths, that is, base cloths constituting tents.
It is manufactured by weaving using these fiber materials.

In general, the properties required of a tent base cloth include structural properties such as water resistance and weather resistance, as disclosed in, for example, JP-A-7-97736.
Conventionally, aesthetics have not been so much demanded.

In recent years, however, aesthetics have been required for tents, especially in the field of eaves tents overhanging the eaves of stores.

In order to give the tent base cloth a luster like cotton for the purpose of improving the aesthetic appearance, the wire diameter of the single yarn constituting the tent base cloth is reduced, and a treatment such as Taslan processing is performed. Although it may be possible to apply it, in the case of tent base fabric using polyester fibers, it is not necessary to twist multiple filaments (single yarn) together during weaving, such as in tire cords, so it is especially necessary to use single yarn. When the fineness yarn has a fineness unevenness that is remarkably recognized, the finer portions may overlap each other as compared with the other portions, so that the base fabric may have a weaker strength portion.

On the other hand, when the single yarn fineness of the polyester fiber is made thin, in the stage of its production, it causes discharge irregularities and fineness irregularities of the undrawn yarn during melt spinning, which causes single yarn breakage. It is known that the quality of the raw yarn is deteriorated because of the occurrence of the above. Further, when the fineness unevenness is large, the strength of the raw yarn varies as described above, and the strength also varies when the base fabric is used, so that it may be broken when used as a tent. There was also the problem of being there.

Conventionally, methods for solving the above problems have been studied, for example, Japanese Patent Laid-Open No. 2000-96335.
In the publication, the ratio (L / D) of the capillary diameter (D) and the capillary length (L) of the die is set to 4 or more, and the draft (DF), which is the ratio of the take-up speed to the discharge linear speed, is set to 3
A method of obtaining a single-filament fine-fineness filament having a high uniformity is proposed by setting the range of 00 ≦ DF ≦ 1250.

However, in the above-mentioned method, when melt-spun polyester having a high viscosity for industrial use, the L / D is large and the pressure applied to the spinning pack is large, which is suitable for operation. In addition to the above, since the draft is high, it tends to be difficult to draw during spinning after spinning, causing an increase in single yarn breakage, and it is difficult to obtain a fiber having sufficient strength as a tent base fabric. was there.

[0009]

SUMMARY OF THE INVENTION In view of the background of the above-mentioned prior art, the present invention has a polyester-like polyester for a tent base cloth, which has an aesthetic luster like cotton, a single yarn fineness and a small strength variation. An object of the present invention is to provide a fiber and an efficient production method thereof.

[0010]

The present invention employs the following means in order to solve the above problems. That is, the polyester fiber for tent base fabric of the present invention has a single yarn fineness of 1.8 to 4.5 dtex and a total fineness of 10
00dtex or less and JIS L-1017 (1
995) has an intensity of 6.0 cN / dt
It is characterized by comprising polyester fibers having ex or more and having a Worcester spot (U%) of 1.0 or less measured according to ASTM D 1425.

Further, the method for producing polyester fiber for tent base cloth of the present invention having the above characteristics has an intrinsic viscosity of 0.
In the process of melt-spinning the polyester of 7 to 1.3 and stretching, the pressure applied to the back surface of the die discharge hole is 5.8.
It is characterized in that the spinning draft, which is the ratio of the linear discharge velocity of the polymer to the take-up roller, is 110 or less.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The present inventors have diligently studied the above-mentioned problems, that is, a polyester fiber for a tent base cloth, which has a luster excellent in aesthetics such as cotton, has a small single yarn fineness and a small variation in strength. However, when a tent base fabric was made by using polyester fibers having specific single yarn fineness, total fineness, strength and Wooster spot, it was clarified that these problems can be solved at once.

The structure and effects of the present invention will be specifically described below.

Examples of the polyester used in the present invention include polyethylene terephthalate, polyethylene naphthalate, polytrimethylene terephthalate and polybutylene terephthalate. Polyesters in which 80 mol% or more of main repeating units are ethylene terephthalate, that is, Polyethylene terephthalate is preferably used.

The polyester may be copolymerized with other acidic components and glycol components as long as the object of the present invention is not impaired. Further, it may be a copolymer of a phosphorus compound or the like as a flame retardant. Specific examples of the acidic component include isophthalic acid and adipic acid, and specific examples of the glycol component include tetramethylene glycol, 1,4-cyclohexanedimethanol and polyethylene glycol, and the phosphorus compound is exemplified. Carboxylphosphinic acid and the like can be mentioned.

Since the tent base cloth is required to have a characteristic that the sheet is not damaged even when a high load is suddenly applied, the polyester fiber for the tent base cloth of the present invention has a luster like cotton. From the viewpoint of obtaining, it is required that the total fineness is small and the single yarn fineness is high, and the strength is high and there is little variation in strength.

That is, the polyester fiber for a tent base fabric of the present invention essentially has the following characteristics.

Single yarn fineness: 1.8 to 4.5 dtex, preferably 1.8 to 3.0 dtex, total fineness: 1000 dtex or less, preferably 850 dt
ex or less, strength: 6.0 cN / dtex or more, preferably 6.6 c
N / dtex or more, Worcester spot (U%): 1.0% or less, preferably 0.7
%Less than.

The strength is JIS L-1017 (1
995), and Worcester's spots (U%) are measured according to ASTM D 1425.

When the total fineness and the single yarn fineness of the polyester fiber for tent base fabric of the present invention exceed the above-mentioned ranges, the surface roughness of the base fabric becomes large, and even if a treatment such as Taslan processing is applied to the raw yarn, It is not preferable because it becomes impossible to obtain gloss like cotton.

On the contrary, if the single yarn fineness of the polyester fiber for tent base fabric is less than the above range, the yarn formability tends to be deteriorated, which is not preferable.

Further, in the polyester fiber for tent base cloth of the present invention, by setting the strength within the above range,
It is possible to maintain the characteristic that the sheet is not damaged even when a high load is applied to the base cloth.

Furthermore, Wooster spots (U%) representing fineness spots
When the value exceeds the above range, the number of single yarn breaks is large and the variation in strength is large, which is not preferable. Not only that, even when the base fabric is used, the thinned portions of the single yarns overlap due to the unevenness of fineness, and the strength of the base fabric also becomes large in the same manner as the variation in the strength of the original yarn, which is not preferable. That is, by setting the Wooster spots (U%) to be within the above range, the variation in the strength of the raw yarn becomes very small,
Even when it is used as a base fabric, the variation in strength is small, and it is possible to exhibit the same strength as the original yarn.

The intrinsic viscosity (I
V) is preferably in the range of 0.70 to 1.30. Here, if the intrinsic viscosity (IV) of the polyester fiber is lower than the above range, the tenacity retention rate of the base fabric after heat treatment is lowered, and it is unsuitable, and if it exceeds the above range, the spinnability is deteriorated. Is deteriorated, fluffing of the raw yarn is likely to occur, and the quality of the base fabric is likely to be impaired, which is not preferable.

The polyester fiber for a tent base cloth of the present invention having the above-mentioned characteristics can be obtained, for example, by the following production method.

That is, a polyethylene terephthalate chip having an intrinsic viscosity (IV) of 1.0 or more is melted, spun from a spinneret attached to a spinning section, and this spun yarn is blown out to a running yarn. It is cooled by cooling air, then an oil agent is applied, and it is taken up at a take-up speed of 300 to 1000 m / min. The method of applying the cooling air to the yarn may be any method conventionally known to those skilled in the art,
For example, a uniflo type or ring type chimney may be used.

The drawn yarn is guided to the drawing process without being wound or after being once wound.
Stretching is performed by multi-stage stretching of two or more stages, and the draw ratio is 2.0.
It may be set in the range of up to 5.0 times. 15 at the same time as stretching
After heat setting at a temperature of 0 ° C. or higher, preferably 200 ° C., it is relaxed by a relaxing roll at a relaxation rate of 1.0 to 3.5% and wound at a winding speed of 2500 m / min or more.

In the above, an important point in the present invention is to set the spinneret under appropriate conditions. That is,
By adjusting the discharge hole diameter D and the discharge hole length L to appropriate values, the discharge linear velocity of the polymer, the value of the spinning draft that is the ratio of the take-up roller, and the back pressure applied to the back surface of the spinneret discharge hole are set to appropriate values. is important.

A proper value of the back pressure is 5.8 to 12 MPa,
Particularly, the value of 7.5-11.0 MPa, the spinning draft is 11
It is 0 or less, particularly 90 or less.

In ordinary melt spinning, it is preferable to make the back pressure at a lower value and the spinning draft at a higher value because of the cost advantage, but it is preferable to use a single fiber like the present invention. In the case of a multifilament having a fineness of yarn, when the back pressure is lower than the above range, the polymer does not evenly reach all the discharge holes in the die, resulting in unevenness of the single yarn fineness. Also, if the back pressure is higher than the above range, it is not appropriate in consideration of the pressure resistance of the pack.

On the other hand, if the spinning draft exceeds the above range, the crystal orientation of the undrawn yarn becomes large, which makes it difficult to draw, and many single yarn breaks occur, which is not preferable.

The polymer discharged from the mouthpiece discharge hole is gradually cooled and solidified by a heating cylinder attached immediately below the mouthpiece and a heat insulating cylinder connected to the heating cylinder. It is well known to those skilled in the art that the yarn fluctuation in the spinning portion near the spinneret has a great influence on Wooster spots, and the Wooster spots can be reduced by adjusting the heating barrel temperature and the heat insulating barrel length to appropriate values. Can be made.

In ordinary melt spinning, the heating cylinder temperature is set to 3
It is preferable that the length of the heat-insulating cylinder, which is a slow cooling zone, is set to 300 mm or more, which is a gradual cooling region following the heating cylinder at 00 ° C. or less, from the viewpoints of yarn-forming property and cost. As the cooling speed increases with
The heating cylinder temperature is 300 to 340 ° C, and the heat insulation cylinder length is 10
0 to 300 mm. The heating cylinder temperature is preferably 32
0 ° C, the length of the heat insulating cylinder is preferably 200 mm,
It may be further shortened as long as it does not affect the operation.

The polyester fiber for a tent base fabric of the present invention thus obtained has a single yarn fineness of 4.5 dtex or less, which is smaller than ever before, for a tent base fabric, and is heat treated such as Taslan processing. In addition to giving cotton-like luster when added as a base fabric, the fineness irregularity represented by Wooster spots (U%) has a value of 1.0 or less, which is lower than conventional values, and the original yarn strength And the variation in the strength of the base cloth is low.

[0035]

EXAMPLES The present invention will be described more specifically below with reference to examples.

Various measured values in the examples are measured by the following methods. [Intrinsic viscosity (IV)]: Using an Ostwald viscometer,
The relative viscosity ηrp of the solution in which 8 g of the sample was dissolved in 100 ml of orthochlorophenol was measured at 25 ° C., and the intrinsic viscosity (IV) was calculated by the following approximate expression.

IV = 0.0242 ηrp + 0.2643 where ηrp = (t × d) / (t0 × d0) where t: drop time of solution (seconds), t0: drop time of orthochlorophenol, d: solution Density of (g / cm
3). [Strength (T)]: Measured based on JIS L-1017 (1995). That is, the Tensilon tensile tester manufactured by Orientec was used to obtain an S-S curve under the conditions of a sample length of 25 cm and a pulling speed of 30 cm / min.
The value was read from the curve. [Variation of strength (σ)]: As described above, JIS L
The strength is measured 10 times according to -1017 (1995),
The standard deviation σ was determined from these measured values. [Wooster spots (U%)]: Measured based on ASTM D 1425. That is, the fineness unevenness was measured by a half inert test using a Wuster yarn unevenness measuring device manufactured by Zellvega, Switzerland. [Single yarn break]: The number of single yarn breaks in the drawn yarn of 3000 m was counted. [Appearance of base fabric (gloss)]: The filament was subjected to Taslan processing and then woven. After that, the appearance of the base fabric was evaluated by 10 people. In the evaluation, the surface of the base fabric having a gloss close to that of cotton was evaluated as ◯, the one having a surface close to that of cotton was evaluated as Δ, and the one having a gloss less than that of cotton was evaluated as x.

[Examples 1 to 3] A polyethylene terephthalate chip having an intrinsic viscosity of 1.21 was used at a polymer temperature of 300 ° C.
Was melted, and spun from a 192-hole spinneret having the conditions shown in Table 1 attached to the spinning section, passed through a heating cylinder heated to 320 ° C., and a 200 mm heat insulating cylinder, and then 635 m / min. It is taken up at a speed, hot-stretched 4.8 times with multiple godet rollers without winding once, and relaxed by 3.0% and wound up 560
detex-192 filament (single yarn fineness 2.9 dt
ex) polyester fiber was obtained.

Table 1 also shows the discharge hole diameter of the die, the die hole depth, the L / D, the spinning draft, the back pressure and the evaluation results of the obtained polyester fiber under each condition.

Examples 4 to 5 Polyester filaments were obtained under the same conditions as in Examples 1 to 3 above. However, the spinneret used was 830 dtex-192 filaments (single yarn fineness 3.9 dtex) and 560 dtex-.
288 filaments (single yarn fineness 1.9 dtex) were selected.

Table 1 also shows the ejection hole diameter of the die, the die hole depth, the L / D, the spinning draft, the back pressure and the evaluation results of the obtained polyester fiber under each condition.

[Comparative Examples 1 to 4] Spinning was carried out by the same method as the manufacturing method of Examples 1 to 5, but the spinneret of the spinning section was changed as shown in Table 1.

Table 1 also shows the discharge hole diameter of the die, the die hole depth, the L / D, the spinning draft, the back pressure and the evaluation results of the obtained polyester fiber under each condition.

[Comparative Examples 5 to 6] Spinning was performed in the same manner as in Comparative Examples 1 to 4, but the spinneret spinner was changed as shown in Table 1 to obtain 560 dtex-384 filaments (single yarn fineness 1 0.5 dtex) and 560 dtex-96 filaments (single yarn fineness 5.8 dtex).

Table 1 also shows the discharge hole diameter of the die, the die hole depth, the L / D, the spinning draft, the back pressure and the evaluation results of the obtained polyester fiber under each condition.

[0046]

[Table 1]

As is clear from the results shown in Table 1, Example 1
The polyester fibers for tent base fabric of Comparative Examples 1 to 5 are Comparative Examples 1 to 6.
Compared to the above, the yarn has a smaller single yarn fineness, has an aesthetic luster like cotton, has less fineness unevenness, and has less variation in strength. I understand.

[0048]

EFFECTS OF THE INVENTION According to the present invention, the single yarn fineness is smaller than before and gives a luster like cotton, and the fineness unevenness has a lower value than before, and the variation in the original yarn strength and the base fabric strength is achieved. It is possible to efficiently provide the polyester fiber for the tent base cloth having a low value.

Continued front page    F-term (reference) 4L035 BB31 BB36 BB40 BB52 BB91                       DD20 EE08 FF01

Claims (4)

[Claims] 1. A single yarn fineness of 1.8 to 4.5 dtex, a total fineness of 1000 dtex or less, and JIS L-1.
The intensity measured based on 017 (1995) is 6.0.
A polyester fiber for a tent base fabric, which is made of a polyester fiber having a Worcester spot (U%) of 1.0 or less at cN / dtex or more as measured according to ASTM D 1425. 2. The polyester fiber for a tent base fabric according to claim 1, wherein the Worcester spot (U%) is 0.7% or less. 3. The polyester fiber for a tent base cloth according to claim 1, wherein the polyester fiber is composed of polyester in which 80 mol% or more of repeating units are ethylene terephthalate units. 4. In the step of melt spinning and stretching a polyester having an intrinsic viscosity of 0.7 to 1.3, the pressure applied to the back surface of the die discharge hole is set to 5.8 to 12 MPa, and a polymer discharge line is used. The method for producing a polyester fiber for a tent base cloth according to any one of claims 1 to 3, wherein the spinning draft, which is the ratio of the speed to the take-up roller, is 110 or less.