JP7402648B2 - Polyphenylene sulfide monofilament, its manufacturing method and its package - Google Patents

Description

The present invention relates to a polyphenylene sulfide monofilament, a method for manufacturing the same, and a package thereof.

Currently, mesh fabrics made of polyphenylene sulfide, polyvinylidene fluoride, liquid crystal polyester, etc. are often used for industrial filters due to their chemical resistance, dimensional stability, heat durability, and the like. In particular, polyphenylene sulfide mesh fabrics are widely used because they have excellent chemical resistance, dimensional stability, and cost performance, and are suitable for fields that require high filter performance.
Patent Document 1 describes a polyphenylene sulfide monofilament characterized by having a fineness of 25 dtex or less, a strength of 3.0 cN/dtex or more, and an elongation of less than 30%.
Further, Patent Documents 2 and 3 describe a drum-shaped package made of polyphenylene sulfide monofilament obtained by a direct spinning/drawing method in which the obtained undrawn yarn is drawn continuously without being wound up once and wound up in a winder. has been done.

Patent No. 4844515 W02016-104236 publication JP 2017-101365 Publication

However, when the elongation is less than 30% like the polyphenylene sulfide monofilaments described in Patent Documents 1 to 3, yarn breakage during spinning and warp breakage during weaving are likely to occur, so mesh This may cause a decrease in the yield of textiles or a decrease in performance. Furthermore, as in Patent Document 1, when a thin pirn is rolled and a monofila with an elongation of nearly 20% is rolled, the 5 and/or 10% modulus becomes high, so pirn sink occurs when the innermost layer is unwound, and the quality deteriorates. may be damaged. Further, in the case of a drum-shaped package as described in Patent Documents 2 and 3, the yarn may fall off from the end face of the bobbin (twill drop), resulting in poor unwinding of the yarn or unwinding. Furthermore, bobbins with twill drop may cause problems during weaving.

Therefore, an object of the present invention is to obtain a high-quality polyphenylene sulfide monofilament that is difficult to break, is difficult to cause bobbin collapse and sink marks during unwinding, and is easy to handle during weaving.

The present inventor has developed a polyphenylene sulfide monofilament that has a specific fineness, breaking strength, breaking elongation, 5% modulus, and 10% modulus by setting the heat setting temperature and winding tension in a specific range and specifying the bobbin package. A monofilament was obtained. This monofilament has better spinning operability than conventional monofilaments, prevents the bobbin from collapsing, reduces sink marks during unwinding, is easy to handle during weaving, and is of high quality. It has been found that polyphenylene sulfide monofilaments can be obtained.
That is, the first gist of the present invention is a polyphenylene sulfide monofilament characterized in that the main structural unit is a p-phenylene sulfide unit and satisfies (1) to (5).
(1) Fineness is 6 to 35 dtex
(2) Breaking strength is 3.4 cN/dtex or more (3) Breaking elongation is 30-40%
(4) 5% modulus is 1.0 to 1.6 cN/dtex
(5) 10% modulus is 1.4 to 2.3 cN/dtex
In addition, the second aspect is a purn-like fiber package made of polyphenylene sulfide monofilament.
Then, a polyphenylene sulfide resin whose main constituent unit is p-phenylene sulfide unit is melt-extruded, cooled and solidified, and the resulting undrawn yarn is continuously stretched without being wound up and then wound up with a winder for direct spinning/drawing. The third gist is a method for producing polyphenylene sulfide monofilament by a method, which is characterized by satisfying (1) to (4).
(1) MFR of polyphenylene sulfide resin is 100-250g/ 10 min
(2) When drawing the undrawn yarn, use an unheated pretension roll and two or more heated godet rolls. (3) The temperature of the first godet roll is 95°C to 120°C, and the temperature of the second and subsequent godet rolls is The heat set temperature of the heated godet roll is 120-250℃
(4) Winding tension to the winder is 0.1 to 0.5 cN/dtex
Furthermore, polyphenylene sulfide resin whose main constituent unit is p-phenylene sulfide unit is melt-extruded, cooled and solidified, and the resulting undrawn yarn is continuously stretched without being wound up and directly wound onto a bobbin with a winder. The fourth aspect is a method for manufacturing a fiber package made of polyphenylene sulfide monofilament by a spinning drawing method, which is characterized in that it satisfies (1) to (4).
(1) MFR of homopolyphenylene sulfide resin is 100 to 250 g/ 10 min
(2) When drawing the undrawn yarn, use an unheated pretension roll and two or more heated godet rolls. (3) The temperature of the first godet roll is 95°C to 120°C, and the temperature of the second and subsequent godet rolls is The heat set temperature of the heated godet roll is 120-250℃
(4) Winding tension to the winder is 0.1 to 0.5 cN/dtex

According to the polyphenylene sulfide monofilament of the present invention, it is difficult to break, has good spinning operability, prevents the bobbin from collapsing, and improves sink marks during unwinding, making it easy to handle during weaving. Become. Furthermore, a polyphenylene sulfide monofilament particularly suitable for a pan-shaped package can be obtained.

The present invention will be explained in detail below.

The polyphenylene sulfide in the present invention is a polyphenylene sulfide resin consisting of a polymer having a phenylene sulfide unit as a main repeating unit. Examples of the phenylene sulfide unit include p-phenylene sulfide unit and m-phenylene sulfide unit. Polyphenylene sulfide may be a homopolymer consisting of p-phenylene sulfide units, m-phenylene sulfide units, etc., or a copolymer containing these units, but from the viewpoint of heat resistance, processability, and economics, Preferred are p-phenylene sulfide repeating units.

Polyphenylene sulfide polymer types include crosslinked types, semi-crosslinked types, and linear types, and linear types are preferred in terms of spinning and stretchability.

In addition, various metal oxides, inorganic substances such as kaolin and silica, colorants, matting agents, flame retardants, antioxidants, ultraviolet absorbers, infrared absorbers, and crystal nucleating agents may be used within the range that does not impair the effects of the present invention. The polyphenylene sulfide may contain small amounts of various additives such as , fluorescent brighteners, terminal group capping agents, and compatibilizers.

The melt flow rate (MFR) of the polyphenylene sulfide resin in the present invention is preferably 100 to 250 g/10 min. More preferably, it is 130 to 200 g/10 min. If it is less than 100 g/ 10 min, the viscosity is too high, causing trouble in spinning. Furthermore, if it exceeds 250 g/ 10 min, the viscosity will be very low and the strength of the fiber will decrease, making it unsuitable for use in mesh fabrics such as filters, as the strength and durability will be greatly reduced. It is.

The moisture content of the polyphenylene sulfide resin pellets before spinning in the present invention is preferably 100 ppm or less, more preferably 10 to 50 ppm. If it exceeds 100 ppm, yarn breakage may occur during spinning, bubbles may be mixed in, and spinning operability may deteriorate.

The polyphenylene sulfide resin pellets in the present invention are preferably pre-dried to remove as much of the low molecular weight components as possible by vacuum drying, and the drying temperature is preferably 130 to 190°C and the drying time is preferably 6 to 12 hours.

Although the cross-sectional shape of the polyphenylene sulfide monofilament of the present invention is not particularly limited, it is preferable that the outer shape of the fiber is circular.

The fineness of the polyphenylene sulfide monofilament of the present invention is preferably 6 to 35 dtex. If it exceeds 35 dtex, it becomes difficult to solidify with cold air, making it difficult to obtain a high-quality monofilament, which causes problems when used as a product such as a filter.

The breaking strength of the polyphenylene sulfide monofilament of the present invention is 3.4 cN/dtex or more, more preferably 3.8 cN/dtex or more, from the viewpoint of the durability of meshes such as filters.

The polyphenylene sulfide monofilament of the present invention has a breaking elongation of 30 to 40%. More preferably, it is 30 to 35%. When the elongation at break is less than 30%, thread breakage occurs frequently during spinning, reed scraping occurs during weaving, and weavability deteriorates. When the elongation at break exceeds 40%, the amorphous portion of the filament increases, resulting in poor dimensional stability of the mesh and reduced durability.

The 5% modulus of the polyphenylene sulfide monofilament of the present invention is between 1.0 and 1.6 cN/dtex, preferably between 1.2 and 1.6 cN/dtex. A higher 5% modulus is preferable from the viewpoint of mesh durability, but if it exceeds 1.6 cN/dtex, sink marks occur when the inner layer of the bobbin is unwound, making it impossible to obtain a high-quality mesh. If it is less than 1.0 cN/dtex, the dimensional stability and strength/durability of the mesh will deteriorate, and misalignment will easily occur.

The 10% modulus of the polyphenylene sulfide monofilament of the present invention is 1.4 to 2.3 N/dtex, preferably 1.7 to 2.1 cN/dtex. A higher 10% modulus is preferable from the viewpoint of mesh durability, but if it exceeds 2.3 cN/dtex, sink marks occur during unwinding of the inner layer of the bobbin, making it impossible to obtain a high-quality mesh. If it is less than 1.4 cN/dtex, the dimensional stability and strength/durability of the mesh will deteriorate, and misalignment will easily occur.

The hot water shrinkage rate of the polyphenylene sulfide monofilament of the present invention is preferably 10% or less. More preferably, it is 2 to 8%. It is preferable to lower the hot water shrinkage rate from the viewpoint of dimensional stability of the mesh. If it exceeds 10%, the dimensional stability of the mesh tends to deteriorate, which may result in a filter of poor quality.

The oil adhesion rate is preferably 0.2 to 0.5% by mass from the viewpoint of the ease with which the polyphenylene sulfide monofilament of the present invention can pass through subsequent processes and obtain a mesh fabric of good quality. More preferably, it is 0.25 to 0.35% by mass. If the amount is less than 0.2% by mass, static electricity is likely to be generated and handling properties such as weaving tend to be poor. If it exceeds 0.5% by mass, scum tends to be generated during weaving, which may affect the quality of mesh fabrics and industrial filters, or cause bobbin collapse during the spinning and winding process.

The method for producing the polyphenylene sulfide monofilament of the present invention involves spinning and then drawing to obtain a monofilament. At this time, it can be produced by a method such as a direct spinning/drawing method or a conventional method. Alternatively, a method may be used in which a parent thread consisting of a multifilament produced by a direct spinning/drawing method is split later to produce a monofilament.
The polyphenylene sulfide monofilament of the present invention can be obtained through a spinning process in which the polyester phenylene sulfide resin is melt-extruded, followed by a stretching process in which it is stretched and wound using an unheated pretension roll and two or more heated godet rolls. A preferred embodiment of the manufacturing method will be described in detail below.
In the spinning process, polyphenylene sulfide melted by an extruder is weighed and oil is applied to the yarn extruded from a nozzle.In the drawing process using multiple godet rolls, the polyphenylene sulfide is sufficiently crystallized and the fiber is Fix the structure and obtain the drawn yarn. During the drawing process, a relaxing process may be introduced for the purpose of reducing the heat shrinkage rate of the drawn yarn. In this case, the relaxation rate in the relaxing step is preferably 0 to 2% from the viewpoint of easily preventing the occurrence of sink marks. A more preferable range of relaxation rate is 0 to 1%. When the relaxation rate is less than 0%, the tension between the rollers in the stretching process becomes high, so the orientation of the amorphous portion becomes high, and sink marks and bobbin winding are likely to occur frequently. When the relaxation rate exceeds 2%, the orientation of the amorphous portion decreases, so that a high-quality monofilament with a 5% modulus and a 10% modulus within the above range and a breaking strength and breaking elongation that meet the present invention is obtained. There is a risk that it will be difficult to wind the thread, and the thread may become loose and winding may not be possible.
In addition, in the stretching process, for the purpose of eliminating deflection, preliminary stretching is performed at a stretching ratio of 1.01 to 1.05 between the pretension roll and godet roll 1, and then main stretching is performed after godet roll 1. It is preferable. In the main stretching, it is preferable to set the temperature of the godet roll 1 at 95 to 120°C. More preferably it is 100 to 115°C. Thereafter, it is successively guided to a godet roll 2, where it is heat set and stretched. The heat setting temperature of the godet roll 2 is preferably 120 to 250°C, more preferably 130 to 200°C. Thereafter, it may be further guided to new goded rolls 3 and goded rolls 4 and stretched. Further, a relaxation process may be performed by providing a relaxation step as described above. Note that when further heat setting is performed on godet rolls after godet roll 3, the temperature is preferably 120 to 250°C, more preferably 130 to 200°C. The goded rolls after goded roll 3 may be non-heated rolls without being heat set. After passing through each roll, the yarn is wound up with a winder. The winding tension when winding it up in a winder is preferably 0.1 to 0.5 cN/dtex. More preferably, it is 0.2 to 0.3 cN/dtex.
In addition, when the temperature of the godet roll 1 is less than 95° C., knot-like bumps occur in the yarn and yarn breakage occurs frequently due to yarn shaking on the godet roll. Furthermore, if the temperature exceeds 120° C., the yarn sways frequently on the godet roll, breaks, and it is difficult to collect monofilament normally. If the temperature of the godet rolls after the godet roll 2 is set by heat is less than 120°C, it becomes difficult to obtain the monofilament of the present invention. Further, if the temperature exceeds 250°C, the monofilament tends to melt due to heat, making it difficult to wind up the monofilament.
If the winding tension to the winder is less than 0.1 cN/dtex, the tension between the godet roll and the winder is too low, resulting in frequent winding failure of the bobbin and thread breakage, making it difficult to normally obtain a monofilament. If it exceeds 0.5 cN/dtex, the winding of the bobbin will occur and it will be difficult to remove the bobbin from the winder.

The bobbin shape of the polyphenylene sulfide monofilament of the present invention is preferably a pirn shape in which the bobbin is wound into a tapered shape around a paper tube used in a commonly used direct spinning drawing method. In general, the direct spinning and drawing method uses a drum type, but in the case of a drum type, when the monofilament is wound, the thread tends to fall off the end face of the bobbin (twill drop), and in severe cases, the winding collapses. If twill drop occurs, the yarn may get caught on the end surface during unwinding, causing yarn breakage or poor weaving, which may reduce process passability and product quality.

The present invention will be explained in detail by giving examples below. Note that the present invention is not limited to the embodiments described below. The physical properties and evaluation of the filaments in Examples were as follows.
A. MFR
JIS K 7210 (1999), the MFR value was measured at a temperature of 315.5° C. and a load of 5000 g.
B. Fineness JIS L 1013, the sample was rolled up at a speed of 120 times/min using a measuring machine with a frame circumference of 1.125 m, and its mass was measured to determine the fineness. This was measured five times and the average value was calculated.
C. Breaking strength, breaking elongation, 5% modulus, 10% modulus JIS L 1013, using an AGS-1KNG Autograph (registered trademark) tensile testing machine manufactured by Shimadzu Corporation, under the conditions of a sample yarn length of 20 cm and a constant tensile speed of 20 cm/min. The value obtained by dividing the highest value of the load on the load-elongation curve by the fineness is defined as the breaking strength (cN/dtex), the elongation rate at that time is defined as the breaking elongation (%), and the strength when the elongation rate is 5% is 5%. % modulus (cN/dtex), and the strength when the elongation rate is 10% is 10% modulus (cN/dtex).
D. Spinning operability The spinning operability was evaluated as ◯ if the process passability was good, △ if the process passability was slightly poor, and × if spinning was impossible.
E. Weavability and Appearance Evaluation Using the obtained polyphenylene sulfide monofilament, weaving was performed using a Sluzer type loom at a rotation speed of 300 rpm, 420 mesh/inch (6 to less than 11 dtex), 225 mesh/inch (11 to less than 21 dtex), and 150 mesh/inch (6 to less than 11 dtex). A mesh fabric of mesh/inch (21-35 dtex) was woven. At that time, weaving properties such as the occurrence of scum on the reed and the state of warp and weft thread breakage, as well as the appearance of the resulting fabric (knots, sink marks, streaks, etc.) were evaluated.
The evaluation was ○ if both weavability and appearance were good, △ if either was bad, and × if both were bad.
F. Mesh performance evaluation Using the obtained polyphenylene sulfide mesh fabric, heat setting was performed at 160° C. for 20 minutes, and the appearance of the processed mesh fabric (before and after heat setting) after being subjected to an elongation recovery cycle was evaluated. The elongation recovery cycle is JIS L 1013, a 10% elongation recovery cycle was performed five times using a Shimadzu AGS-1KNG Autograph (registered trademark) tensile testing machine under the conditions of a sample length of 20 cm, width of 5 cm, and constant tension speed of 20 cm/min. do. The appearance of the mesh fabric at that time was visually observed. Items with no misalignment, distortion, or damage were rated “〇,” items with distortion or slight damage were rated “x,” and items for which the presence or absence of distortion or damage could not be determined were rated “△.”
G. Comprehensive evaluation Regarding the three items of spinning operability, weavability and appearance evaluation, and mesh strength and durability, if all of the items are evaluated as 〇, “〇”, if there is one or more △ and no ×, “△”, If even one item had a cross, it was marked as “x”.

[Example 1]
A p-polyphenylene sulfide resin (moisture content: 20 ppm) with an MFR of 160 g/10 min was prepared and melted at a spinning temperature of 328°C. The molten polyphenylene sulfide was discharged using a spinning nozzle with two holes (L/D=0.65 mm/0.65 mm) at a discharge rate such that the fineness after stretching was 33 dtex. The discharged polyphenylene sulfide yarn is cooled with a uniflow type cooling device, an emulsion oil is applied (OPU = 0.3% by mass), and then the yarn is passed through an unheated pretension roll at a speed of 1040 m/min. After winding up, tension was applied between godet rolls 1 (speed 1058 m/min, 115 °C), main stretching and heat setting were performed with godet roll 2 (speed 3520 m/min, 135 °C), and godet roll 3 (speed 3500 m). Polyphenylene sulfide monofilament of 33 dtex was wound on a winder (speed 3495 m/min) with a winding tension of 0.2 cN/dtex (speed 3495 m/min), and a polyphenylene sulfide monofilament of 33 dtex was placed on a pirn-shaped bobbin with a tapered end surface. I flipped it up.

[Example 2]
A polyphenylene sulfide monofilament of 33 dtex was obtained except that the speed of the pretension roll was 920 m/min, the speed of Goded Roll 1 was 960 m/min, and Goded Roll 3 was not used.

[Comparative Examples 1 and 2]
In Comparative Example 1, a polyphenylene sulfide monofilament of 33 dtex was obtained in the same manner as in Example 2, except that the temperature of Godedroll 2 was changed. Comparative Example 2 was carried out under these conditions.

[Comparative Examples 3 and 4]
In Comparative Example 4, a polyphenylene sulfide monofilament of 33 dtex was obtained in the same manner as in Example 2, except that the speed of the winder and the winding tension were changed. Comparative Example 3 was carried out under these conditions.

[Comparative example 5]
A polyphenylene sulfide monofilament of 33 dtex was obtained in the same manner as in Example 1, except that p-polyphenylene sulfide resin with an MFR of 300 g/10 min was used and the speeds of the pretension roll and godet roll 1 were changed.

[Comparative example 6]
A polyphenylene sulfide monofilament of 33 dtex was obtained in the same manner as in Example 2, except that p-polyphenylene sulfide resin with an MFR of 65 g/10 min was used and the speeds of the pretension roll and godet roll 1 were changed.

[Example 3]
A p-polyphenylene sulfide resin having an MFR of 160 g/10 min was prepared and melted at a spinning temperature of 328°C. The molten polyphenylene sulfide was discharged using a spinning nozzle with two holes (L/D=0.35 mm/0.31 mm) at a discharge rate such that the fineness after stretching was 10 dtex. The discharged polyphenylene sulfide yarn was cooled with a uniflow type cooling device, an emulsion oil was applied, and the same procedure as in Example 1 was carried out except that the conditions listed in Table 1 were applied, such as a pretension roll, godet rolls 1 and 2, 3 and wound up into a winder to obtain a polyphenylene sulfide monofilament of 10 dtex.

[Example 4]
A p-polyphenylene sulfide resin having an MFR of 160 g/10 min was prepared and melted at a spinning temperature of 328°C. The molten polyphenylene sulfide was discharged using a spinning nozzle having two holes (L/D=0.4 mm/0.37 mm) at a discharge rate such that the fineness after stretching was 13 dtex. The discharged polyphenylene sulfide yarn was cooled with a uniflow type cooling device, an emulsion oil was applied, and the same procedure as in Example 1 was carried out except that the conditions listed in Table 1 were applied, such as a pretension roll, godet rolls 1 and 2, 3 and wound up into a winder to obtain a polyphenylene sulfide monofilament of 14 dtex.

[Example 5]
A polyphenylene sulfide monofilament of 33 dtex was obtained in the same manner as in Example 1, except that the heat setting temperature of Goded Roll 3 was 190°C.

[Comparative Examples 7 and 8]
Polyphenylene sulfide monofilament was produced in the same manner as in Example 1, except that the temperature of Godedroll 1 was changed as shown in Table 1.

[Comparative example 9]
A polyphenylene sulfide monofilament of 33 dtex was obtained in the same manner as in Example 1, except that the elongation was 22% by lowering the speed of the pretension roll and godet roll 1 in Example 1, and the temperature of godet roll 2 was 150 ° C. .

[Comparative Example 10]
A polyphenylene sulfide monofilament of 33 dtex was prepared in the same manner as in Example 1, except that the elongation was 50% by increasing the speed of the pretension roll and goded roll 1 in Example 1, and the temperature of goded roll 2 was set at 150°C. Obtained.

[Comparative Example 11]
A polyphenylene sulfide monofilament of 33 dtex was obtained in the same manner as in Example 2, except that the temperature of the goded roll 2 was changed to 190° C. and the winding tension was changed to 0.6 cN/dtex.

[Comparative example 12]
A polyphenylene sulfide monofilament of 33 dtex was obtained in the same manner as in Example 2, except that the temperature of the godet roll 2 was 110° C. and the bobbin package was changed to a drum type.

Table 1 shows the manufacturing conditions, yarn physical properties, and results of each evaluation (spinning operability, weavability and appearance evaluation, mesh performance evaluation and comprehensive evaluation) of polyphenylene sulfide monofilaments of Examples 1 to 5 and Comparative Examples 1 to 12. show.

The polyphenylene sulfide monofilaments obtained in Examples 1 to 5 were high-strength, high-quality monofilaments with few knots. In addition, the mesh fabrics using the monofilaments obtained in Examples 1 to 5 do not generate scum, do not have warp or weft yarn breakage, and their appearance does not include streaks, thick yarns, or luster due to sink marks or other factors. It was of good quality with no abnormalities. Furthermore, it has sufficient strength and good dimensional stability, making it highly durable and of good quality when used as a filter. Among them, the mesh fabrics obtained from the monofilaments of Examples 1 and 5 had particularly excellent fiber properties, no sink marks, no streaks, etc.
The mesh fabric obtained from the polyphenylene sulfide monofilament obtained from Comparative Example 1, which had a low heat setting temperature, had low dimensional stability, misalignment was observed, had low strength and durability, and was of poor quality. This is probably because the strength of the polyphenylene sulfide monofilament obtained from Comparative Example 1 was low and the hot water shrinkage rate was high.
In the polyphenylene sulfide monofilament obtained from Comparative Example 2, which had a high heat setting temperature, the yarn on the godet roll 2 suffered from fusing, yarn breakage, and shaking, and the monofilament could not be collected into a bobbin.
In the polyphenylene sulfide monofilament obtained in Comparative Example 3, in which the winding tension to the winder was lowered, the thread loosened between the godet roll 2 and the winder, frequently winding it onto the godet roll 2 and unwinding it on the bobbin, and the monofilament did not function normally. It was not possible to collect the sample into the bobbin.
The polyphenylene sulfide monofilament obtained in Comparative Example 4, which had a high winding tension on the winder, had a high winding tension, so if the amount of winding exceeds 1 kg, the winding becomes tight and cannot be removed from the winder, so mass production is not possible. It was not suitable for In addition, regarding the weavability of the mesh fabric obtained by thin winding, the 5% modulus and 10% modulus were high, so sink marks occurred in the inner layer of the bobbin, streaks appeared in the mesh fabric, and the quality was poor. . In addition, the mesh fabric was stretched during heat setting during weaving, causing misalignment and other problems, resulting in poor quality.
The polyphenylene sulfide monofilament obtained from Comparative Example 5 using a polyphenylene sulfide resin with a high MFR had a very low viscosity, and even when the elongation was close to 30%, the strength was only 3.2 cN/dtex. As a result, the strength and durability of the mesh fabric deteriorated, resulting in poor quality.
The polyphenylene sulfide monofilament obtained in Comparative Example 6 using a polyphenylene sulfide resin with a low MFR has a very high viscosity, tends to generate unmelted substances and gels, causes frequent yarn shaking on the gogged roll, and almost no monofilament is produced. could not be collected. Because monofilament has knots, warp threads frequently break during weaving. The resulting mesh fabric had lines and knots caused by sink marks, and was of poor quality, resulting in a considerably low quality product.
The polyphenylene sulfide monofilament obtained from Comparative Example 7 in which the preheating temperature of godet roll 1 was lowered was about 10°C lower than the glass transition temperature of polyphenylene sulfide, so that the stretching between godet rolls 1 and 2 caused a mixture of unstretched parts. After Gode Roll 2, the yarn path was shaking so much that it was almost impossible to wind the monofilament onto the bobbin.
The polyphenylene sulfide monofilament obtained in Comparative Example 8 in which the preheating temperature of goded roll 1 was increased is about 40°C higher than the glass transition temperature of polyphenylene sulfide, so the yarn on goded roll 1 loosened, causing large yarn sway. However, due to frequent thread breakage, monofilament could not be obtained.
The polyphenylene sulfide monofilament obtained from Comparative Example 9, in which the elongation of the monofilament was lowered to 22%, had a low elongation and was likely to break during spinning. Further, even if the bobbin was relaxed, the 5% modulus and 10% modulus became high, so sink marks occurred when the bobbin was unwound. The mesh fabric using this monofilament had streaks due to sink marks and was of poor quality. In terms of performance, the factors that occurred during weaving were inherited, resulting in inferior performance and poor appearance.
The polyphenylene sulfide monofilament obtained from Comparative Example 10, in which the elongation of the monofilament was increased to 50%, had good spinning runnability, but the strength and 5% and 10% modulus were considerably low. The dimensional stability of the mesh fabric was very poor. Mesh fabrics also suffer from misalignment due to stretching, resulting in extremely poor strength and durability.
The polyphenylene sulfide monofilament obtained from Comparative Example 11, in which the heat setting temperature was 190°C and the winding tension was 0.6 cN/dtex, had a high winding tension, so winding tightness occurred when the winding amount exceeded 1 kg. , it was not suitable for mass production because it could not be removed from the winder. In addition, in the weavability evaluation of the mesh fabric when rolled thinly, sink marks occurred in the inner layer of the bobbin when it was unrolled, and streaks appeared in the fabric, resulting in poor quality. This is probably due to the high 10% modulus.
The polyphenylene sulfide monofilament obtained from Comparative Example 12, which had a low heat set temperature of 110° C. and a drum-shaped bobbin package, had a low heat set temperature, low breaking strength, and high hot water shrinkage rate. Furthermore, during weaving, since the bobbin was shaped like a drum, threads fell off the end face of the bobbin (twill drop). As a result, thread breakage occurs due to poor unwinding of the bobbin during weaving, the dimensional stability of the mesh fabric decreases, the strength and durability of the mesh fabric decreases, and the quality of the mesh fabric deteriorates.

As described above, the polyphenylene sulfide monofilaments obtained in Examples 1 to 5 are of high quality with almost no occurrence of streaks due to sink marks, reed scraping, scum, knots, or yarn breakage during weaving, and are strong. there were. The obtained mesh fabrics before and after processing have almost no appearance abnormalities such as lines due to misalignment or sink marks, and have excellent dimensional stability and strength, making them highly suitable for use in high-performance filter applications. It was a thing of dignity.

Claims (4)

A polyphenylene sulfide monofilament whose main structural unit is a p-phenylene sulfide unit and which satisfies (1) to (5).
(1) Fineness is 6 to 35 dtex
(2) Breaking strength is 3.4 cN/dtex or more (3) Breaking elongation is 30-40%
(4) 5% modulus is 1.0 to 1.6 cN/dtex
(5) 10% modulus is 1.4 to 2.3 cN/dtex A yarn-like fiber package comprising the polyphenylene sulfide monofilament according to claim 1. A direct spinning/drawing method is used in which polyphenylene sulfide resin whose main constituent unit is p-phenylene sulfide is melt-extruded, cooled and solidified, and the resulting undrawn yarn is continuously stretched without being wound up and wound in a winder. A method for producing polyphenylene sulfide monofilament according to claim 1, characterized in that (1) to (4) are satisfied.
(1) MFR of polyphenylene sulfide resin is 100-250g/ 10 min
(2) When drawing the undrawn yarn, use an unheated pretension roll and two or more heated godet rolls. (3) The temperature of the first godet roll is 95°C to 120°C, and the temperature of the second and subsequent godet rolls is The heat set temperature of the heated godet roll is 120-250℃
(4) Winding tension to the winder is 0.1 to 0.5 cN/dtex A polyphenylene sulfide resin whose main constituent unit is p-phenylene sulfide is melt-extruded, cooled and solidified, and the resulting undrawn yarn is continuously stretched without being wound up and wound onto a bobbin using a winder. Direct spinning/drawing 4. A method for manufacturing a fiber package made of polyphenylene sulfide monofilament by a method according to claim 2 or 3, characterized in that (1) to (4) are satisfied.
(1) MFR of polyphenylene sulfide resin is 100-250g/ 10 min
(2) When drawing the undrawn yarn, use an unheated pretension roll and two or more heated godet rolls. (3) The temperature of the first godet roll is 95°C to 120°C, and the temperature of the second and subsequent godet rolls is The heat set temperature of the heated godet roll is 120-250℃
(4) Winding tension to the winder is 0.1 to 0.5 cN/dtex