JP3433750B2 - Method for producing polyester monofilament for screen gauze - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a polyester monofilament for screen gauze. For more details,
The present invention relates to a polyethylene terephthalate monofilament composed of a single component having excellent dimensional stability.

[0002]

2. Description of the Related Art Screen gauze fabrics are widely used for screen printing, filters and the like. Conventionally, natural fibers such as silk and inorganic fibers such as stainless steel have been used as materials. However, in recent years, organic fibers such as nylon and polyester, which have stable quality and are easily available, have been generally used. In particular, screen gauze fabrics made of polyester monofilaments are becoming more widespread because they are less affected by moisture in dimensional stability than nylon, have excellent heat resistance, and are inexpensive.

[0003] For screen mesh fabrics for printing such as electronic circuits which require particularly high precision, it is essential to have high dimensional stability. Therefore, it is desired to increase the dimensional stability of the polyester monofilament itself which constitutes the screen gauze fabric.

As a method for increasing the dimensional stability of this polyester monofilament, the applicant of the present invention has disclosed that in Japanese Patent Application Laid-Open No.
-95895 and Japanese Patent Application Laid-Open No. 2-289120, the elongation of 10% obtained in a constant speed tensile test of 100% / min.
Modulus (strength) at 3.5g / d or more (3.1c
N / dtex or more) is proposed.

The present inventors have found that a monofilament consisting of polyethylene terephthalate as a single component, which does not rely on composite spinning, can be used as a screen gauze with excellent dimensional stability by applying ordinary processing conditions for gauze. It was found that the conventional design based on the modulus at 10% elongation cannot add a stress relaxation element having a relatively long time scale. In particular, it has been found that it does not directly correspond to loosening of the tension of the screen, which occurs over time after the screen is stretched, and distortion of the figure when repeated printing is performed. further,
The modulus at 10% elongation measured by the above-mentioned measuring method is a measure of dimensional stability in the same polymer system and the same yarn making system, but is used as a measure of dimensional stability when the polymer system and the yarn making system are changed. Was found to be inappropriate.

The characteristics required of a monofilament for realizing precision screen printing, which is represented by printing of electronic circuits, are that it has high strength, high elastic modulus, and high tensile tension. Furthermore, a monofilament with small stress relaxation and excellent dimensional stability is required.

[0007]

SUMMARY OF THE INVENTION In view of such conventional drawbacks, the present invention provides a single component polyethylene terephthalate monofilament having excellent dimensional stability,
The purpose is to realize precision screen printing.

[0008]

The above-mentioned object of the present invention is to obtain a monofilament composed of polyethylene terephthalate as a single component, which has a modulus of 1% at an elongation of 2% obtained by a constant rate tensile test of 5% / min. in the method for manufacturing a monofilament made of screen mesh cloth for polyester monofilament, which is a 7 g / d or more (1.5 cN / dtex or higher), after stretching heat-treated undrawn yarn, leading to a non-heating roller, 130-160 ℃
It can be achieved by a method for producing a polyester monofilament for a screen gauze, characterized in that the drawn yarn between the heated drawing roller and the non-heated roller held by is wound while giving a stretch ratio of 0.1 to 10%.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION That is, the present invention provides an elongation of 1 to 4% obtained by a low speed tensile test of polyester monofilament.
It was discovered that a polyester monofilament with small stress relaxation and excellent dimensional stability can be obtained by increasing the modulus in the low elongation region at that time, and completed a material suitable for precision screen printing.

The modulus at the elongation of 1 to 4% depends on the tensile speed in the constant speed tensile test. Since relaxation also progresses simultaneously in the tensioning process, the slower the tensile speed, the greater the contribution of relaxation. Conventionally known JIS-L-1013 (19
In 81), the constant speed tensile test (tensile speed is 100% / min or 50% / min) has a small contribution of relaxation, and cannot be seen to correspond to stress relaxation characteristics.

In the present invention, the tensile speed in the constant speed tensile test is 5
It is based on the new finding that the modulus at 1 to 4% elongation point of the stress-strain curve (hereinafter referred to as low-speed S-S) obtained at a very low speed of about% / min corresponds well with the stress relaxation characteristic. When the modulus at 1.7% elongation of 2% is 1.7 g / d or more (1.5 cN / dtex or more), the elongation of the obtained screen gauze is small at the time of setting the raw machine, and the gauze frame is covered with the gauze The subsequent tension relaxation is small, the dimensional change during screen printing is small, and a polyester monofilament for screen gauze suitable for electronic circuit printing on a printed circuit board or the like can be obtained.

Even if the modulus at normal high speed S-S is high, the modulus at 1 to 4% elongation point of low-speed S-S is 1.7 g / d (1.5 cN / dte).
When it is smaller than x), the polyester monofilament has a short stress relaxation time. For this reason, when a screen printing plate is used, the printing plate tends to stretch during printing, resulting in a decrease in printing accuracy. Here, the low-speed SS means a sample length of 200 mm,
It is an SS curve measured at a pulling rate of 5% / min.

The low-speed SS curve of the polyester monofilament of the present invention having such physical properties is shown in FIG. 1 in the range of elongation 0 to 5% (breaking strength elongation is not shown). (A) is the polyester monofilament of the present invention. (B) is a conventional polyester monofilament, which is inferior in dimensional stability. In FIG. 1, E2 is 2% elongation,
T2 is the modulus at 2% elongation.

The method for producing the polyester monofilament of the present invention can be obtained by appropriately adjusting the stretching heat treatment conditions of melt-spun polyester. For example, polyethylene terephthalate having an intrinsic viscosity of 0.65 to 1.2 is melt-spun at a temperature of 290 to 300 ° C., and subsequently, while the discharged yarn is cooled and solidified, 60
At the time of drawing at 0 to 1300 m / min, and then drawing heat treatment of the obtained undrawn yarn at a draw ratio of 3 to 5 times, a roller-based drawing device, an example of which is shown in FIG.
And heating the supply roller 3 which is heated to a high temperature, 1 3 0-1 8
It is stretched 3 to 5 times with the heating stretching roller 4 heated to 0 ° C. Temperature of the heating stretching roller 4 is required to be 1 3 0~1 6 0 ℃. 1 3 0 ° C. tight winding of the winding yarn 6 is increased in the following, the solution of the monofilament舒性decreases. On the other hand, when the temperature is 180 ° C or higher, the modulus at the 2% elongation point due to the low speed S-S decreases, so that the dimensional stability becomes low.
It The yarn which is heat-drawing by the upper SL, is guided to the non-heating roller 5 subsequently provide 0.1-10 percent stretch ratio in the stretching yarn between the heating and drawing roller 4 unheated roller 5 It is something that is rolled up. Here, the roller 5 is not heated in order to quickly cool the temperature of the drawn yarn that has exited the heated drawing roller 4 and suppress the instantaneous elastic recovery of the wound yarn. Therefore, the roller 5 needs not be heated.
There is . More preferably, a means such as circulating cooling water may be used.

In the polyester monofilament of the present invention, since the stretching ratio between the heating supply roller and the heating stretching roller can be set to an appropriate ratio, the modulus of the 2% elongation point of the monofilament is 1.7 g / d or more (1.5 cN /
Although it is high (dtex or more), the breaking elongation is 30 to 45.
% Can be obtained, which is also preferable for suppressing scum. Further, it is not necessary to increase the winding tension on the winder, and it is preferable for the unwinding property such as suppressing panning during weaving.

By the way, when 0% to 3% of relaxation is applied between the heated drawing roller and the non-heated roller and the film is wound, the modulus at the 2% elongation point due to the low speed SS is 1.3 to 1.5.
The g / d is small (1.1 to 1.3 cN / dtex), is easily plastically deformed, and lacks in dimensional stability, which is not preferable.

As another method of increasing the modulus of the 2% elongation point by the low speed SS to 1.7 g / d or more (1.5 cN / dtex or more), stretching between the heating supply roller and the heating stretching roller is performed. There is a method to increase the magnification, but in this method, the breaking elongation of the monofilament becomes low,
Scum generation is severe during weaving, which makes it difficult to weave a good screen gauze. Furthermore, the tension is set to 0.
There is also a method of increasing it to 5 g / d or more (0.4 cN / dtex or more), but if the winding tension is made higher, the hardness of the winding yarn wound around the drum, pan, etc. becomes higher and the unwinding tension becomes higher. Therefore, when weaving, so-called pan shrinkage occurs and the quality of the screen gauze is impaired.

The polyester of the present invention is required to be polyethylene terephthalate, which is used in large quantities for clothing and industrial applications in consideration of cost and the like.

The denier of the monofilament is not particularly limited, but is 4 to 50 d (4 to 56 dte).
x) can be applied.

In the present invention, the tensile speed in the constant speed tensile test is 5
It is based on the new finding that the modulus at 1 to 4% elongation point of the stress-strain curve (hereinafter referred to as low-speed S-S) obtained at a very low speed of about% / min corresponds well with the stress relaxation characteristic. Modulus at elongation of 2% is 1.7g
/ D or more (1.5 cN / dtex or more), the elongation of the obtained screen gauze when set to a raw machine is small, and the tension relaxation after it is stretched on the gauze frame is small,
A dimensional change during screen printing is reduced, and a polyester monofilament for screen gauze suitable for electronic circuit printing on a printed circuit board or the like can be obtained.

The dimensional stability referred to in the present invention is described below.
Stress relaxation time (λ _1.25).
The following exponential function is generally used as the stress relaxation equation.
It

Λ = t / 1n (F₀/ Ft) λ: Stress relaxation time (seconds) F₀: Initial stress (g / d) Ft: Stress after relaxation for t seconds (g / d) t: measurement time (seconds) 200mm test length using Tensilon tensile tester
F at speed 5% / min₀= 1.25 g / d (1.10 cN /
When the tension reaches dtex), pulling is stopped and after
Is a constant length and shows the tension after t = 1200 seconds.
Read from, F_{12 00}(G / d) is calculated and λ is calculated from the following formula.
_1.25Was calculated. However, the measurement temperature was 25 ° C.

Λ _1.25 = 1200 / 1n (1.25 / F
₁₂₀₀ ) (sec) Here, the larger λ _1.25 , the better the dimensional stability. The present inventors have found that when the λ _{1.25 of} the polyester monofilament is 5000 seconds, the dimensional accuracy when used for screen printing is good. However, since it takes a long time to measure λ _1.25 , the influence of a minute measurement temperature during the measurement appears and the measured value tends to fluctuate.
Therefore, various studies have been conducted on a simple property that can be substituted for λ _1.25 , and the 2% elongation point modulus by the low speed SS of the present invention has been found. That is, the low speed S
The 2% extension point modulus due to -S has a high correlation with λ _1.25 and is easy to measure. Therefore, the number of measurements n can be increased and a highly accurate measurement value can be obtained.

The 2% elongation point modulus of low-speed SS referred to in the present invention uses an average value of the number of measurement n = 10.
In order to set λ _1.25 to 5000 seconds or more, the modulus at the 2% elongation point due to the low speed SS is 1.7 g / d or more (1.5
cN / dtex or more) is required.

[0025]

Example 1 Granular polyethylene terephthalate having an intrinsic viscosity of 0.8 measured at 35 ° C. in an o-chlorophenol solution was extruded from a spinneret having four holes at a spinning temperature of 300 ° C., solidified by cooling, and then a water emulsion oil agent. Is applied by an oiling roller, and the undrawn yarn is wound into four at a yarn speed of 900 m / min. Subsequently, a single yarn fineness of 1 is obtained by using the drawing device shown in FIG.
A 2d (13 dtex) monofilament was obtained. The stretching device and the stretching conditions are as follows.

Tension of unstretched yarn 1: 0.2 g / d
(0.18 cN / dtex) (unstretched single yarn fineness) Temperature of heating supply roller 3: 92 ° C. Temperature of heating stretching roller 4: 140 ° C. Temperature of non-heating roller 5: Room temperature Winding yarn tension 6: 0. 25 g / d (0.22c
N / dtex) (Wind single yarn fineness) Draw ratio between the heating supply roller 3 and the heating drawing roller 4: 4
Stretching ratio between the double heating stretching roller 4 and the non-heating roller 5:
2% Stretching speed (speed of unheated roller 5): 800 m / min The modulus of 2% elongation point in the low speed SS of the polyethylene terephthalate monofilament obtained above is 1.9 g / d (1.7 cN / dtex), The stress relaxation time λ _1.25 was 7500 seconds, and a monofilament excellent in dimensional stability could be obtained. The monofilament was also well unwound from the drum.

Comparative Example 1 In Example 1, the tension of the winding yarn 6 was 0.25 g / d without removing the non-heating roller 5 and applying stretch.
A monofilament having a single yarn fineness of 12 d (13 dtex) was wound at (0.22 cN / dtex) (winding single yarn fineness). The obtained polyethylene terephthalate monofilament had a modulus of 2% elongation at low speed SS of 1.5 g / d (1.3 cN / dtex) and a stress relaxation time λ _1.25 of 4500 seconds and was inferior in dimensional stability. .

Example 2 In Example 1, the speed of the heated stretching roller 4 was changed to change the stretch ratio between the heated stretching roller 4 and the non-heated roller 5. Table 1 shows the modulus of 2% elongation point, the stress relaxation time λ _1.25 , the dimensional stability, and the unwinding property of the monofilament from the drum of the obtained 12d (13dtex) polyethylene terephthalate monofilament at low speed SS.

[0029]

[Table 1] As is clear from Table 1, the 2% elongation point modulus due to the low speed S-S and the stress relaxation time λ _1.25 have a high correlation, and the stretching ratio of the heating roller and the non-heating roller is 0.1 to 1.
It is important to set the content to 0%, and the monofilament obtained by the method of the present invention has a large modulus at the 2% elongation point in low-speed SS and is excellent in dimensional stability.
Further, the unwinding property of the monofilament was also satisfactory.

[0030]

The polyester monofilament for screen gauze obtained by the production method of the present invention has excellent dimensional stability. Therefore, when it is used for screen printing, the dimensional stability is good and the printing accuracy is improved. You can Therefore, it is suitable for screen mesh printing, such as an electronic circuit, which requires high precision.

[Brief description of drawings]

FIG. 1 is a low-speed SS curve, (A) is an example of the polyester monofilament of the present invention,
(B) is an example of a conventional polyester monofilament.

FIG. 2 is a diagram showing an example of a stretching device for obtaining the polyester monofilament of the present invention.

[Explanation of symbols]

E2: 2% elongation T2: Modulus at 2% elongation 1: Undrawn yarn 2: Supply roller 3: Heating supply roller 4: Heat stretching roller 5: Non-heated roller 6: drawn yarn

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Claims (2)

(57) [Claims] 1. A method for producing a monofilament comprising polyethylene terephthalate as a single component, wherein an undrawn yarn is drawn and heat treated, and then introduced to a non-heated roller, and 130-1
A method for producing a polyester monofilament for a screen gauze, which comprises winding a stretched yarn between a heated stretching roller and a non-heated roller held at 60 ° C while giving a stretch ratio of 0.1 to 10%. 2. The modulus at 1% elongation obtained by a constant rate tensile test of 5% / min by the manufacturing method according to claim 1 is 1.
A method for producing a polyester monofilament for a screen gauze, which comprises obtaining a monofilament having a weight of 7 g / d or more (1.5 cN / dtex or more).