JPH0633334A - Drawing of monofilament for screen gauze - Google Patents

Abstract

PURPOSE:To suppress the fluctuation of drawing tension and obtain a monofilament suitable for high-precision screen gauze by drawing undrawn thermoplastic monofilament yarn with a hot roller under a condition to get a friction coefficient between the running yarn and metallic mirror surface falling within a specific range. CONSTITUTION:Undrawn monofilament yarn A composed of a thermoplastic polymer such as polyethylene terephthalate is hot-drawn in a state wound prescribed turns around a hot feed-roller 3 and a hot drawing roller 4 via respective pairing separate rollers 3a, 4a. The feed-roller has a mirror-polished surface having a surface roughness of 0.1S to 2.0S. In the above process, the friction coefficient of the running yarn to the metallic mirror surface between the hot feed-roller 3 and the hot drawing roller 4 is controlled to 0.2-0.7 under a condition to satisfy the formula 3 deg.<=theta<=15 deg. wherein theta is the angle between the drawn yarn B and the tangential line of the hot feed-roller 3 at the final yarn- separation point Q in the rotational direction of the roller.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for drawing a monofilament. More specifically, it relates to a stretching method capable of obtaining a monofilament for a screen gauze, which has less fineness unevenness, less scum during weaving, and excellent in high-precision printing.

[0002]

2. Description of the Related Art As a screen fabric for printing, a mesh fabric composed of natural fibers such as silk and inorganic fibers such as stainless steel has been widely used. However, recently, with emphasis on flexibility and durability, mesh fabrics made of organic fibers such as nylon and polyester are often used. In particular, a screen gauze made of polyester monofilament is becoming popular because it has less influence on dimensional stability due to moisture absorption and the like, is excellent in heat resistance, and is low in price as compared with nylon.
However, in the recent printing field of electronic circuits,
The demand for improvement in printing accuracy is becoming more and more strict, and a screen gauze having a high strength, a high elastic modulus and a uniform opening, that is, a uniform opening, and a screen gauze having a uniform thickness are required. For this reason, the monofilament to be used inevitably has a high strength and a high elastic modulus, and needs to be a uniform monofilament with no fineness unevenness.

In particular, reducing the fineness unevenness of the monofilament enables the opening of a uniform size to be obtained in the opening portion which is the printing ink passage portion of the screen plate, and makes it possible to increase the line width accuracy of the printed matter. Since the ink thickness can be made uniform by making the thickness of the part uniform, this is an extremely important issue in high precision screen printing.

In general, in order to obtain a drawn yarn having a small fineness unevenness, it is sufficient to reduce the fluctuation of the drawing point in the drawing process of the undrawn yarn. Therefore, many proposals have been made so far. For example, Japanese Examined Patent Publication (Kokoku) No. 45-35805 proposes a stretching device in which an elastic roller that is pressed and rotated is provided on the surface of a heating supply roller, and a hot plate is arranged between the heating supply roller and the stretching roller. In the stretching device, the yarn is pressed by the elastic roller or the stretched yarn is brought into contact with the hot plate, so that the yarn surface is easily scratched. When used as a monofilament for screen gauze, the scratches cause scum during weaving. There is a problem that occurs. Furthermore, since the elastic roller pressed against the heating supply roller gradually deteriorates due to heat and hardens, the maintenance of the functionality of the elastic roller is complicated, and there is a problem that the cost becomes high as an industrial production process. .

Further, Japanese Patent Application Laid-Open No. 48-56917 proposes a stretching method in which the roller surface roughness on the supply roller side is 0.4 S or less. The drawing method prevents slippage during drawing, but there is a problem that the effect is small in the drawing of monofilaments. This is because in the drawing of the monofilament using the heating supply roller, the drawing point accompanied by necking is located slightly upstream of the yarn separation point. The yarn between the drawing point and the yarn separating point runs at a speed higher than the surface speed of the supply roller, and in that sense, slip always occurs on the surface of the supply roller. Therefore, uniform stretching cannot be achieved by simply preventing slippage.

Therefore, the method of stretching the monofilament for suppressing the generation of scum and achieving the precision printing, that is, suppressing the fluctuation of the stretching point to obtain the fineness unevenness in the longitudinal direction,
Fibers due to abrasion, dirt, etc. on the roller surface caused by reducing the variation of the SS curve or by eliminating the variation between the weights due to the difference in the processing precision between the rollers due to the roller processing precision, and by the change over time in the stretching It is necessary to solve scratches on the surface and unevenness of stretching at the same time.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the prior art by suppressing the generation of scum, enabling precise printing, and producing a monofilament. Fineness variation in the longitudinal direction, S-
An object of the present invention is to provide a method for stretching a monofilament for a screen gauze, which can reduce variations in the S curve, variations between the weights, and the like, and can enhance the uniformity of the opening.

[0008]

The above-mentioned object of the present invention is to heat a monofilament undrawn yarn made of a thermoplastic polymer with a heating supply roller having a surface finish roughness in the range of 0.1S to 2.0S. The running yarn friction coefficient with respect to the metal mirror surface is 0.2 to
When forming a monofilament drawn yarn in the range of 0.7, the angle θ formed by the yarn at the yarn separation point of the heating supply roller and the tangent in the roller rotation direction is set to 3 ° ≦ θ ≦ 15 °. This is achieved by a method for stretching a monofilament for screen gauze.

The present invention will be described in detail below. Generally, when heat drawing is performed by a drawing system including a heating supply roller and a heating drawing roller, the drawing point is located slightly upstream of the yarn separation point of the final winding of the heating supply roller, and therefore the drawing point and the yarn separation The yarn between the points runs at a high speed within the range of the peripheral speed of the heating / drawing roller, not the peripheral speed of the heating / supplying roller, and therefore runs while slipping between the drawing point and the yarn separating point. . Therefore, the friction coefficient between the roller surface and the yarn is important. However, if the friction coefficient is increased, the stretching tension is difficult to be smoothly transmitted to the stretching point, while if the friction coefficient is reduced, the gripping property of the stretching point is deteriorated, and in any case, there is a problem that uneven stretching is likely to occur. It was Therefore, as a result of earnest studies by the present inventors, the inventors have found a stretching method in which the friction coefficient is increased up to the stretching point and the frictional resistance between the stretching point and the yarn separating point is reduced.

That is, in the present invention, the angle θ between the drawn yarn between the heating supply roller and the heating drawing roller and the tangent line in the roller rotation direction at the yarn separation point of the final winding of the heating supply roller.
By setting (hereinafter simply referred to as angle θ) to 3 ° ≦ θ ≦ 15 °, it becomes possible to reduce the frictional resistance between the drawing point and the yarn separating point.

This is the angle θ between the drawing point and the yarn separation point.
Since the drawn yarn runs along the irregularities (fine polishing grooves formed in the roller circumferential direction) of the mirror surface polishing groove of the heating supply roller and runs toward the yarn separating point, the contact area becomes small,
The frictional resistance decreases between the drawing point and the yarn separating point. Further, since the twisting force acts from the heating supply roller on the yarn traveling from the drawing point to the yarn separating point due to the addition of the angle θ, the vertical drag force is reduced and the distance between the drawing point and the yarn separating point is reduced. Therefore, the frictional resistance is reduced. By reducing the frictional resistance between the drawing point and the yarn separating point, the drawing tension is smoothly transmitted to the drawing point, and the fluctuation of the drawing point position is reduced. As a result, a uniform monofilament with a small fineness unevenness is obtained.

Incidentally, Japanese Patent Publication No. 46-2766 discloses that
In a stretching device provided with two or more Nelson rolls, a device has been proposed in which at least one Nelson roll is attached while being inclined with respect to a reference plane. FIG. 3 of the proposed publication shows an example in which the yarn separation point has an angle of θ ₃ . However, the device is intended to simplify the arrangement and installation area of the device,
With such an apparatus alone, it was not possible to obtain a uniform monofilament with a small fineness unevenness.

Here, if the angle θ is less than 3 °, the inclination angle of the monofilament from the drawing point to the yarn separating point becomes extremely small, and the effect of reducing the frictional resistance during this time also becomes small. Therefore, the angle θ needs to be 3 ° or more, preferably 4 ° or more. Also, the angle θ
When the angle exceeds 15 °, the stretching point itself starts to move in the angle imparting direction, so that the variation of the stretching point position becomes large. Therefore, the angle θ needs to be 15 ° or less, and preferably 10 ° or less.

Further, according to the method of the present invention, the surface finish roughness (according to the finish roughness symbol of JIS indication) is 0.1 S or more.
It is important to use a mirror-finished heating supply roller in the range of 2.0S. The surface of the heating supply roller in the present invention is fixed to the stable drawing point by increasing the frictional resistance up to the drawing point in the relationship between the surface of the heating supply roller and the friction resistance of the monofilament. On the other hand, the frictional resistance between the drawing point and the yarn separating point is reduced to reduce the stress fluctuation of the drawn yarn. In order to achieve both of these conflicts, it is important to make the surface roughness of the heating supply roller appropriate. If a heating supply roller having a surface roughness of less than 0.1 S is used, the friction coefficient between the surface of the heating supply roller and the monofilament becomes high. Therefore, the effect of the angle θ cannot be obtained, the frictional resistance between the surface of the heating supply roller and the monofilament becomes high between the drawing point and the yarn separating point, and the fixing of the drawing point is hindered, resulting in uneven drawing. Furthermore, when a heating supply roller having a surface roughness of more than 2.0 S is used, the friction coefficient between the surface of the heating supply roller and the monofilament does not reach the friction coefficient enough to receive the drawing tension, and the drawing point is fixed. I cannot get enough friction resistance. Depending on the temperature and the draw ratio, the draw point is not located in the last turn but moves in the upstream direction, and the distance between the draw point and the yarn separation point becomes longer, increasing the abrasion resistance and causing the yarn to sway and stabilize. No stretch point can be obtained. Therefore,
It is necessary to use a heating supply roller having a heating roller surface finish roughness of 0.1S to 2.0S. The range is preferably 0.1S to 1.5S. The surface finishing method of the heating supply roller used in the present invention may be a mirror surface. Further, the roller may be divided into rollers having different surface finish roughness, but at least between the drawing point and the yarn separating point is 0.
It must be kept in the range of 1S to 2.0S.

Further, since the effect of imparting the angle of the present invention varies depending on the friction coefficient between the surface of the heating supply roller and the monofilament, the addition amount of titanium oxide or alumina particles, which is well known as an additive for a thermoplastic polymer, It is advisable to optimize the composition and amount of the spinning oil agent.

The surface finish roughness of the monofilament stretched yarn is 0.2 by attaching a spinning oil agent having a high friction against metal.
When the coefficient of friction of the running yarn with respect to the chrome mirror finishing roller of S is 0.7 or more, even if the angle θ is increased to more than 10 °, it is difficult to fix the stretching point and it is difficult to improve the fineness unevenness. Becomes

Further, a monofilament having a running yarn friction coefficient of more than 0.7 is not preferable because scum is liable to be generated due to rubbing by the yarn guides, the feathers, etc. not only in the yarn making process but also in the weaving process. On the other hand, when the running yarn friction coefficient is less than 0.2, the friction coefficient between the surface of the heating supply roller and the monofilament does not reach the drawing tension, and the frictional resistance for fixing the drawing point cannot be obtained. . Therefore, depending on the temperature of the heating supply roller, the draw ratio, etc., the draw point is not located at the last turn but moves in the upstream direction, the distance between the draw point and the yarn separation point becomes long, and the abrasion resistance increases. For this reason, the yarn swinging on the heating supply roller becomes large, and a stable drawing point cannot be obtained.

Therefore, the addition amount of titanium oxide or alumina particles, which is well known as an additive for thermoplastic polymers,
It is necessary to optimize the composition, amount of adhesion, etc. of the spinning oil agent so that the running yarn friction coefficient of the monofilament drawn yarn with respect to the surface finish roughness 0.2S mirror finish roller is in the range of 0.2 to 0.7. , Preferably 0.2 to 0.6. The method for measuring the running yarn friction coefficient will be described later.

The stretching method of the present invention will be described below with reference to the drawings. The drawings show one embodiment of the stretching method according to the present invention. FIG. 1 is a front view showing the whole, FIG. 2 is a side view showing the main part thereof, and FIG. 3 is an enlarged view of the vicinity of a heating supply roller. . In each figure, 1 is a pressing nip roller,
Reference numeral 2 is a feed roller, 3 is a heating supply roller paired with a 3a separate roller, 4 is a heating drawing roller paired with a 4a separate roller, 5 is a drive roll, and 6 is drawn yarn cheese.

In FIG. 1, the undrawn yarn A is fed at a constant speed by the pressing nip roller 1 and the feed roller 2, and the secondary transition temperature Tg is obtained.
A stretch ratio of 0.2 to 3% is given between the heating supply roller 3 and the heating supply roller 3 heated to a temperature higher by 10 ° C. to 30 ° C. to apply the yarn tension to the undrawn yarn A, and then the heating supply rollers 3 and 120 are used.
The angle θ formed between the drawn yarn and the tangent line in the roller rotation direction at the yarn separation point of the final winding of the heat supply roller between the heated drawing roller 4 heated to 80 ° C. to 180 ° C. is 3 ° ≦ θ ≦ 15 °. The stretched yarn B stretched to 5 times and heated and drawn is
If necessary, apply tension heat treatment to drive roller 5
It shows a state in which the drawn yarn cheese 6 is wound by using. As a winding method, as shown in FIG. 1, the drawn yarn cheese 6 may be wound using the drive roller 5, or may be wound in a pan shape using a twister that uses spindle rotation.

FIG. 2 shows an example of the relationship between the inclined installation positions of the heating supply roller 3 and the heating drawing roller 4 in FIG. 1 and the relationship of the yarn path. Here, the heating supply roller rotating shaft is shown. The drawing shows a state in which an angle θ formed by the drawn yarn and a tangent line in the roller rotation direction at the yarn separation point of the final winding of the heating and supplying roller is provided by inclining with respect to the reference plane. FIG. 3 shows the yarn path of the heating supply roller 3 in FIG. 2, and by installing the heating supply roller 3 at an inclination, the yarn separation point Q deviates from the circumference of the stretching point P and the stretching point The yarn traveling from P to the yarn separating point Q shows a state in which the yarn travels on the surface of the heating and supplying roller 3 while being inclined at an angle θ.

In the present invention, the method for satisfying the specified angle θ is most efficiently achieved by inclining the rotary shaft of the heating supply roller with respect to the reference plane, and it is preferable. It may be attached so as to be inclined with respect to the surface. Further, the heating supply roller and the heating stretching roller may be attached at the same time while being inclined with respect to the reference plane. The method is not limited as long as the angle θ (see FIG. 3) formed between the drawn yarn between the rollers of the present invention and the tangent line of the roller rotation direction at the yarn separation point of the final winding of the heating supply roller is achieved. is not.

In the present invention, the thermoplastic polymer may be nylon 6 or nylon 66 typified by polyamide, and more preferably polyester. The polyester is a polyester in which at least 80 mol% or more of the constitutional unit is ethylene terephthalate or butylene terephthalate, and may be a copolymer of a small amount of aliphatic dicarboxylic acid or polyalkylene glycol. In addition, polyethylene-2,6 having a high elastic modulus
-Naphthalate and the like can also be used.

The drawing method of the present invention can also be applied to a method of drawing a composite-spun undrawn yarn. The fineness of the monofilament is not particularly limited, but the method of the present invention can be applied to 4 to 50 denier. Here, the undrawn yarn is one that is once wound around a drum, but it may be a method in which the yarn is directly stretched without being wound around the drum, and a plurality of monofilaments are formed on the same weight as adjacent yarns. The present invention can also be applied to a method in which the yarns are stretched with a space provided between them so long as the contact resistance between the yarns due to the contact does not occur.

[0025]

EXAMPLES The present invention will now be described in more detail by way of examples. The physical properties in the examples were measured as follows. (A) Fineness unevenness It was measured using a yarn unevenness tester manufactured by Zellbeger Worcester. The measurement conditions are shown below. Measured yarn feeding speed: 200 m / min Measured yarn length: 200 m / min Range scale: ± 12.5% Thread tension: 0.3 g / d Suction air pressure: 7 kg / cm ² Fineness unevenness is indicated by a normal measurement value.

(B) Variation in tenacity at 10% elongation Tensileon tensile tester manufactured by Orientec Co., Ltd. was used to determine from the load elongation curve. The measurement was performed by dividing a continuous sample into 30 cm and making it continuous in the longitudinal direction.
It was measured up to m. (Repeated measurement number of times: 50) The measurement conditions are shown below. Measurement sample length: 20 cm Tension speed: 20 cm / min Chart speed: 30 cm / min Load range: Rated 5 kgf / full scale 0.1
kgf

(C) Uniformity of opening The processed gauze is observed by a transmission microscope and the opening distance (distance between adjacent weft threads and weft threads or warp threads and warp threads forming the gauze) is n = Each of 100 pieces was measured, and the standard deviation was obtained for each. The smaller the obtained standard deviation was, the more uniform the opening was, and the more accurate the gauze was judged to be. By setting the fineness unevenness to 0.6% or less, a gauze with uniform opening and good accuracy can be obtained. Further, the quality of the gauze is observed by observing the fibrous scum woven into the gauze, and the number of scum per 1 m of gauze is 0.2 or less, and those without the fibrous scum are judged as good gauze.

(D) Coefficient of friction of running yarn It was expressed as a coefficient of friction μ when measured under the following conditions using a mirror-finished chrome pin of 35 mmφ and 0.2S. Traveling yarn entry side tension: T1 = 10g Traveling yarn exit side tension: T2 = measured value Contact angle: 90 ° Threading speed: 2.5m / min μ = (2 / π) ・ ln (T1 / T2)

Examples 1 to 5 and Comparative Examples 1 to 3 Granular polyethylene terephthalate having an intrinsic viscosity of 0.8 measured with an o-chlorophenol solution at 35 ° C. and containing 0.5% by weight of titanium oxide was used at a spinning temperature of 295. Extruded from a spinneret with a circular cross-section of 4 holes at ℃ (hole diameter 0.4 mmφ),
After cooling and solidification, 0.3% by weight of the following oil agents A, B, C, and D was applied to the fiber, and the yarn was divided into 4 at a speed of 1000 m / min to obtain a single yarn fineness of 48 denier and fineness variation of 0.5%. The monofilament undrawn yarn was wound on a drum. The unstretched yarn was stretched between the feed roller and the heating supply roller at 95 ° C. by a stretch ratio of 0.5%, and then the heating supply roller was heated under the conditions of roughness and yarn angle shown in Table 1. 130
Draw at a draw ratio of 4.0 times with a heating draw roller at 0 ° C., and draw the resulting drawn yarn at a draw speed of 800 between a heated draw roller and a non-heated roller at a stretch ratio of 1%.
12 d of monofilaments for screen gauze having different running yarn friction coefficients were obtained under the condition of / min. Table 1 shows the running yarn friction coefficient μ, the fineness variation, the tenacity variation CV% at the elongation of 10%, and the opening uniformity of the obtained monofilament for screen gauze. The breaking strength of this monofilament was 6 g / d, the breaking elongation was 32%, the initial tensile resistance was 125 g / d, and the strength at an elongation of 2% was 2.2 g / d.
It was a high-strength, high-modulus monofilament. Oil agent A: running filament friction coefficient of monofilament μ = 0.15 Oil agent B: 〃 = 0.25 Oil agent C: 〃 = 0.50 Oil agent D ： 〃 = 0.75

[Table 1] As is clear from Table 1, when the running filament friction coefficient μ of the monofilament is within the range of the present invention, the fineness unevenness is 0.7%.
Shown below is a drawing method capable of reducing the standard standard knitting difference CV% at an elongation of 10%, and the obtained screen gauze has good opening uniformity and no scum. . On the other hand, when the running yarn friction coefficient μ exceeds 0.7 or is less than 0.2, it is difficult to reduce the fineness unevenness to 0.7% or less.

Examples 6 to 13 Granular polyethylene terephthalate having an intrinsic viscosity of 0.7 measured with an o-chlorophenol solution at 35 ° C. and containing 0.1% by weight of titanium oxide was used at a spinning temperature of 290 ° C. and a 4-hole spinneret. Further extruded, after cooling and solidification, apply the oil agent B,
A monofilament unstretched yarn having a single yarn fineness of 47 denier and a fineness unevenness of 0.5% was wound up on a drum by dividing into 4 at a speed of 1000 m / min. The undrawn yarn was fed to a feed roller at 90 ° C.
After a stretch ratio of 0.5% is applied between the heating supply roller and the heating supply roller, the heating supply roller and the heating stretching roller at 130 ° C. are heated under the conditions of the surface roughness of the heating supply roller and the angle θ of the yarn shown in Table 2. Between the heated stretching roller and the non-heated roller by 1.5%
Was added to obtain a 12d monofilament for screen gauze at a stretching rate of 800 / min. Fineness variation and elongation of the obtained monofilament for screen gauze 1
Table 2 shows the variation ratio CV% of the strength at 0% and the uniformity of the opening. The running yarn friction coefficient μ of each monofilament obtained here was about 0.45.

[0031]

[Table 2] As is clear from Table 2, the monofilament produced by the stretching method of the present invention shows a stretching method capable of reducing the unevenness of fineness and the standard knitting difference CV% of tenacity at an elongation of 10%. The uniformity was good and no scum was generated.

Examples Comparative Examples 4 to 9 Stretching was carried out under the conditions of Example 2 except that the unstretched yarn of Example 2 was used and the surface roughness and yarn angle of the heating supply roller were changed as shown in Table 3. The evaluation results are shown in Table 3.

[0033]

[Table 3] As is clear from Table 3, the object of the present invention could not be achieved if either the surface roughness of the heating supply roller or the angle θ of the yarn deviates from the range of the present invention in each of the comparative examples.

[0034]

The monofilament drawing method for screen gauze of the present invention suppresses fluctuations in the drawing tension, and has a fineness variation in the longitudinal direction and a variation variation of the SS curve in the longitudinal direction, which is a measure of quality uniformity. A uniform stretch with a small variation in the weight difference is applied, which can improve the uniformity of the opening, and a stable stretch of gauze that satisfies the characteristics required for high-precision screen printing of electronic circuits etc. You can

[Brief description of drawings]

FIG. 1 is a front view showing an embodiment of a stretching device according to the present invention.

FIG. 2 is a side view showing the main part of FIG.

FIG. 3 is an enlarged view of the vicinity of a heating supply roller according to the present invention.

[Explanation of symbols]

1: pressing nip roll 2: feed roller 3: heating supply roller 3a: separate roller 4: heating stretching roller 4a: separate roller 5: non-heating roller 5a: separate roller 6: drive roller 7: stretched yarn cheese A: unstretched yarn B : Stretched filament P: Stretched point Q: Thread separation point θ: Angle between the yarn at the point Q and the tangent to the roller rotation direction

Claims (1)

[Claims] 1. A monofilament unstretched yarn comprising a thermoplastic polymer is heat-stretched in a stretching system comprising a heating supply roller and a heating stretching roller having a surface finish roughness in the range of 0.1S to 2.0S, When forming a monofilament stretched yarn having a running yarn friction coefficient of 0.2 to 0.7 with respect to a metal mirror surface, the angle θ formed by the yarn at the yarn separation point of the heating supply roller and the tangent line in the roller rotation direction is 3 °. ≤ θ ≤ 15
A method for stretching a monofilament for a screen gauze, which is characterized in that