JP7009752B2 - Pack base for melt spinning - Google Patents

Description

The present invention relates to a pack base for melt spinning used in a silk reeling process of a thermoplastic polymer. More specifically, a filament of uniform quality is obtained by equalizing the viscosity unevenness caused by the difference in heat history of the melt spinning pack mouthpiece of the molten polymer and supplying it to the mouthpiece discharge hole. In addition, the present invention relates to a pack base for melt spinning, which suppresses thermal deterioration of the polymer due to a decrease in residence time and makes it possible to obtain good yarn-making properties by merging in a small space.

Generally, in the production of fibers for melt-spinning thermoplastic polymers, the raw material chips are melt-kneaded with an extruder to form a melt-kneaded polymer, and the polymer is applied to the melt-spun pack mouthpiece through the polymer piping installed in the heating box. Guide. The introduced polymer removes foreign matter in the polymer by passing through the filter media and filters laminated in the melt spinning pack mouthpiece, is distributed by a perforated plate, and the polymer is spun from the discharge hole of the mouthpiece to form a filament. obtain.

Such a pack mouthpiece for melt spinning is installed in a heating box in order to maintain the molten state of the polymer, and is heated at a high temperature. Therefore, the temperature of the inner layer portion of the melt spinning pack mouthpiece in contact with the heating box is lower than that of the outer layer portion, and a temperature difference occurs between the inner and outer layers inside the melt spinning pack mouthpiece. As a result, the polymer passing through the inner and outer layers of the pack mouthpiece for melt spinning causes viscosity unevenness due to the difference in heat history, resulting in a non-uniform polymer, which causes a difference in physical properties between the single yarns spun from each discharge hole. It will occur. Further, the molten polymer is thermally deteriorated when the residence time, which is the time affected by heat, becomes long, and the deteriorated polymer causes operational malfunctions such as fluff and yarn breakage, and the yarn-making property is impaired.

Therefore, in order to equalize the viscosity unevenness caused by the heat history difference in the molten polymer passing through the melt spinning pack base, suppress the quality difference, and suppress the thermal deterioration due to the influence of the residence time, the melt spinning pack base is used. Has been studied in various ways.

For example, Patent Document 1 describes a confluence flow path in which a molten polymer is confluent at one location while being contracted at the center of a melt spinning pack mouthpiece, and an equal interval extending downstream from the outlet at the end of the confluence. A plurality of circular tubular flow paths arranged in a circle, an opening at the beginning of which the polyma of the discharge hole group bored evenly on the circumference flows in, and an end opening of the circular tubular flow path are annular. Disclosed is a technique for merging a polymer at the center of a melt spinning pack mouthpiece to make it uniform and reducing a difference in physical properties between single yarns by constructing an annular flow path formed to connect the yarns.

Further, in Patent Document 2, the molten polymer is collected in a single-hole collecting hole and then passed through a stationary kneading element to knead and disperse the molten polymer to make it uniform, between single yarns or by melt spinning. A technique for reducing the difference in physical properties between the pack caps is disclosed.

Japanese Unexamined Patent Publication No. 2010-111977 Japanese Unexamined Patent Publication No. 2008-81860

However, as a result of verifying the spinning pack base for molten spinning described in Patent Document 1, the number of times the polymer is merged is small for the molten polymer which has a high viscosity and is in a laminar flow state only by merging at one place. Therefore, a sufficient polymer mixing effect cannot be obtained. Therefore, the uniformity of the viscosity unevenness caused by the difference in heat history between the inner and outer layers is not sufficient, and the quality difference between the single yarns cannot be eliminated. Regarding the residence time, it is described that the difference in residence time is eliminated by dividing the flow path into a circular tubular flow path and flowing a polymer, but studies are made to reduce the residence time itself and suppress thermal deterioration. Not done.

Further, the pack mouthpiece for melt spinning described in Patent Document 2 is a stationary system in order to obtain a sufficient polymer mixing effect and to ensure the kneading property so that the viscosity unevenness caused by the difference in thermal history between the inner and outer layers can be made uniform. It is necessary to lengthen the kneading element. Therefore, the residence time increases due to the increase in the length of the polymer flow path due to the lengthening of the pack base member for melt spinning, which tends to cause thermal deterioration of the polymer and impairs the silk-reeling property. Further, there is a problem that the space for installing another pack base member for melt spinning is limited by the required length of the stationary kneading element.

The present invention solves the problems of the prior art, and in melt spinning of a thermoplastic polymer, when the molten polymer flows through the pack mouthpiece for melt spinning, the melt viscosity unevenness caused by the difference in heat history between the inner and outer layers of the pack mouthpiece for melt spinning is caused. By making it uniform and supplying it to the mouthpiece discharge hole, it is possible to obtain a filament of uniform quality. In addition, it is an object of the present invention to provide a pack base for melt spinning, which can suppress thermal deterioration of a polymer due to a decrease in residence time and obtain good yarn-making property by merging a plurality of times in a small space.

That is, the present invention has the following configuration.
(1) In a pack mouthpiece for melt spinning in which filter sand, a filter, a perforated plate, a merging plate, and a mouthpiece for spinning a thermoplastic molten polymer are arranged in this order.
The merging plate has a plurality of flow path holes in the upstream part in the polymer spinning path direction, and the flow path holes merge multiple times as the flow path holes move toward the downstream in the polymer spinning path direction to form one flow path hole in the most downstream direction. Multiple multi-stage merging microchannels are formed , and the flow path volume of each multi-stage merging microchannel is the same. One flow path hole located at the most downstream in the direction of the polymer spinning path of the flow path is a pack mouthpiece for melt spinning that communicates with each discharge hole of the mouthpiece.
(2 ) The pack mouthpiece for melt spinning according to (1 ) , wherein the plurality of flow path holes in the upstream portion of the multi-stage merging fine flow path in the polymer spinning path direction are formed on the radius line of the merging plate.
( 3 ) The pack mouthpiece for melt spinning according to (1) or (2) , wherein the confluence plate has a thickness of 2 mm or more and 60 mm or less.

According to the present invention, in the melt spinning of a thermoplastic polymer, when the melt polymer flows through the pack mouthpiece for melt spinning, the unevenness in melt viscosity caused by the difference in heat history of the pack mouthpiece for melt spinning is made uniform and supplied to the mouthpiece discharge hole. This makes it possible to obtain filaments of uniform quality. In addition, by merging a plurality of times in a small space, it is possible to provide a pack base for melt spinning, which suppresses thermal deterioration of the polymer due to a decrease in residence time and makes it possible to obtain good yarn-making properties.

It is a schematic normal sectional view schematically illustrating the melt spinning pack mouthpiece of this invention. It is a schematic normal sectional view (enlarged view) which schematically exemplifies the merging plate and the mouthpiece of this invention. It is a schematic isometric view (semi-cross-sectional view) which schematically exemplifies the arrangement of the merging plate multi-stage merging microchannels of this invention.

Embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic cross-sectional view schematically illustrating the pack mouthpiece for melt spinning of the present invention. In FIG. 1, 1 is a spinning pack mouthpiece, 2 is a polymer introduction hole, 3 is a filter layer portion, 4 is a filter medium, 5 is a filter, 6 is a perforated plate, 7 is a confluence plate, 8 is a mouthpiece, and 9 is a discharge hole. show.

The flow of the polymer of the pack base for melt spinning of the present invention will be described. The spinning pack base 1 of FIG. 1 is installed in a high-temperature heating box in order to maintain the molten state of the polymer, and the melted polymer is supplied to the spinning pack base 1 through the polymer introduction hole 2. The supplied polymer passes through the filter medium 4 made of fine sand or the like in the filter layer portion 3 and the filter 5 made of wire mesh or sintered porous metal, so that foreign matter in the polymer can be removed. Remove it. After that, the polymer from which the foreign matter has been removed is distributed by the perforated plate 6, passes through the confluence plate 7 that merges the flow path holes through which the polymer flows a plurality of times, and the discharge hole 9 of the base 8, and is spun out as a filament.

FIG. 2 is a schematic forward sectional view (enlarged view) schematically illustrating the merging plate 7 and the base 8 installed in the melt-spun pack base of the present invention. In FIG. 2, the multi-stage merging fine flow path 7a is composed of an inner layer portion multi-stage merging fine flow path hole group 7b and an outer layer portion multi-stage merging fine flow path hole group 7c, and the base 8 is a discharge hole flow to the discharge hole 9. It has a road 8a.

The pack mouthpiece for melt spinning of the present invention is provided with a merging plate 7 between the perforated plate 6 and the base 8, and the merging plate 7 has a plurality of flow path holes in the upstream portion in the direction of the polymer spinning path. As the channel holes merge toward the downstream in the direction of the polymer spinning path, they merge a plurality of times, and a plurality of fine multi-stage merging channels forming one channel hole at the most downstream are formed. With this configuration, when the polymer passes through the merging plate 7, the polymer flowing from each flow path hole is gradually merged in the multi-stage merging fine flow path 7a. Further, the polymers gradually and repeatedly merged are finally aggregated and merged into one channel hole to form a uniform polymer. Further, since the polymer merging is performed a plurality of times, even a polymer in a laminar flow state having a high viscosity can be surely mixed.

Next, the number of multi-stage merging fine flow paths 7a of the merging plate 7 is the same as that of the discharge holes 9 of the mouthpiece, and the flow path holes at the most downstream in the polymer spinning path direction of each multi-stage merging fine flow path are in the mouthpiece 8. It is preferable that it is formed so as to communicate with the discharge hole 9 through a certain discharge hole flow path 8a. With such a configuration, the volume of the flow path between the merging plate 7 and the base 8 can be shortened, so that thermal deterioration of the polymer can be suppressed, and the filament can be spun out with the minimum residence time. Further, by forming a multi-stage merging fine flow path having the same flow path volume in each discharge hole, the difference in thermal history of the polymer can be eliminated, and the difference in physical properties between single yarns can be further suppressed.

The multi-stage merging fine flow path 7a of the merging plate 7 has a group of fine flow path holes in the outer layer portion (a group of multi-stage merging fine flow path holes in the outer layer portion) among a plurality of flow path holes located upstream in the direction of the polymer spinning path. , The microchannel holes in the inner layer (multi-stage confluence microchannels in the inner layer 7b) are gradually merged toward the downstream in the direction of the polymer spinning path, and one channel hole is formed at the most downstream. It is preferable that a multi-stage merging fine flow path is formed. As the polymer passes through this fine multi-stage merging flow path, the polymer with different thermal history differences between the inner layer and the outer layer is gradually merged and kneaded, and finally merged into one channel hole. As a result, a uniform polymer with more uniform viscosity can be obtained, and filaments of uniform quality can be obtained.

Further, in order to obtain a uniform polymer with more uniform viscosity, it is more preferable to increase the number of flow path holes in the multi-stage merging fine flow path 7a and increase the number of repeated merging. Although FIGS. 1 to 3 show a small number of merging stages for a simple explanation, it is further provided that the number of merging stages is 5 or more for one multi-stage merging fine flow path 7a so that the merging is performed 5 times or more. preferable.

FIG. 3 is a schematic isometric diagram (semi-cross-sectional view) schematically illustrating the arrangement of the multi-stage merging microchannels of the merging plate 7 of the present invention. In FIG. 3, 7d indicates a multi-stage merging fine flow path group, 10 indicates a merging plate radius line, and 11 indicates an angle between the radius lines.

Regarding the arrangement of the multi-stage merging fine flow paths of the merging plate 7, the polymers having different thermal history differences between the inner layer part and the outer layer part of the pack mouthpiece for melt spinning are efficiently merged and kneaded to obtain a more uniform polymer with more uniform viscosity. In order to obtain the multi-stage merging fine flow path group 7d on the merging plate radius line 10, and in order to suppress the difference in physical properties between the discharge holes, the merging plate radius in which the multi-stage merging fine flow path group 7d is located. It is preferable to arrange the multi-stage merging fine flow path group 7d so that the radius line angle 11 indicated by the merging plate radius line 10 adjacent to the line 10 and the radius line center angle becomes equal.

Further, in order to suppress the occurrence of a residence time difference between each single yarn, the flow path volumes of the multi-stage merging fine flow path shapes are the same so that the pressure loss due to the difference in the flow path volume does not differ in each multi-stage merging fine flow path 7a. It is preferable to form a flow path.

The thickness of the merging plate 7 is preferably 2 mm to 60 mm. It is more preferably 2 mm to 40 mm, still more preferably 2 mm to 10 mm. With such a configuration, the length of the polymer flow path can be shortened, the residence time can be reduced, thermal deterioration can be suppressed, and good silk reeling properties can be obtained.

Since the merging plate used for the pack mouthpiece for melt spinning of the present invention forms a plurality of fine multi-stage merging flow paths inside, it is very difficult to cut out and form the internal flow paths by ordinary machining. As a manufacturing method, for example, a merging plate can be divided perpendicularly to the polymer spinning path direction axis, a flow path is processed and manufactured on the divided plate, and the divided plates are laminated to form the merging plate. For machining each divided plate, each machining such as drilling, machining, and laser machining is used. By laminating a plurality of divided plates manufactured by these processing methods, it is possible to manufacture a multi-stage merging fine flow path having a merging number of times inside with a merging plate thickness of 2 mm to 60 mm. By making the merging plate thinner and shortening the polymer flow path length as compared with the prior art, it is possible to reduce the residence time and suppress thermal deterioration. In addition, since the merging plate can be made thin, even when it is additionally incorporated into an existing pack, there is little change in other members because the installation space is small, and it has the advantage of being easy to incorporate.

The pack mouthpiece for melt spinning of the present invention can obtain a more remarkable effect in a fine fineness variety having a single yarn fineness of 6 to 30 dtex and a variety having a small number of filaments. This is because the fineness varieties and varieties with a small number of filaments have a smaller amount of polymer discharged, so that the amount of heat carried by the polymer into the pack mouthpiece for melt spinning is smaller, and the heat history differs between the inner layer and outer layer of the pack. The temperature unevenness of the polymer that it has tends to increase, and the effect of viscosity unevenness tends to appear. Further, the amount of polymer inflow per discharge hole is small, the residence time is likely to increase, and the effect of thermal deterioration is likely to be increased accordingly.

The thermoplastic polymer used in the present invention is not particularly limited as long as it is a thermoplastic resin that can be melt-spun. For example, polyester represented by polyethylene terephthalate, polytrimethylene terephthalate, polybutylene terephthalate, polylactic acid, polyethylene naphthalate, etc., and polyamide represented by nylon 6, nylon 66, etc. can be exemplified.

Further, the pack mouthpiece for melt spinning of the present invention is not limited to the homogenization of the single component polymer. For example, when applied to a composite polymer using two or more types of polymers, it is possible to knead the polymers by repeating the merging, and it is also possible to promote the compounding of the polymers. Further, by changing the number of merging of the multi-stage merging fine flow paths, it is possible to easily control the kneading degree of the composite polymer.

Hereinafter, the present invention will be described in more detail with reference to examples. The method for measuring the characteristic value in the examples is as follows.

(1) Fineness 1. Set the fiber sample on a measuring instrument with a circumference of 125 m / circumference, rotate it 400 times to make a loop-shaped skein, dry it with a hot air dryer (105 ± 2 ° C x 60 minutes), and then balance. The fineness was calculated from the value obtained by measuring the skein mass and multiplying by the official moisture content. The official moisture content was 4.5%.

(2) Fineness difference The fineness of each single yarn obtained from one mouthpiece was measured according to (1), and the difference between the maximum fineness value and the minimum fineness value was taken as the fineness difference. 2% or less with respect to the standard fineness was evaluated as ◯, and when it exceeded 2%, it was evaluated as ×. (3) Sulfuric acid relative viscosity 0.25 g of polyamide chips were dissolved so as to be 1 g in 100 ml of sulfuric acid having a concentration of 98% by mass. , The flow time (T1) at 25 ° C. was measured using an Ostwald viscometer. Subsequently, the flow time (T2) of sulfuric acid having a concentration of 98% by mass was measured. The ratio of T1 to T2, that is, T1 / T2, was defined as the relative viscosity of sulfuric acid.

(4) Silk-reeling property Regarding the thread breakage per ton when producing synthetic fibers, 1.0 times or less was evaluated as ◯, and more than 1.0 times was evaluated as x.

[Example 1]
Nylon 6 chips with a relative sulfuric acid viscosity of 2.73 were melted at 285 ° C., and a plurality of filter media (filter sand), filters, perforated plates, and multi-stage confluence microchannels shown in FIG. 1 were formed at a discharge rate of 22.5 g / min. A pack mouthpiece for melt spinning in which existing merging plates and caps are arranged in order (number of discharge holes 48, number of threads 6, number of multi-stage merging fine flow paths 48, number of merging stages for one multi-stage merging microchannel, 5 stages of merging plate thickness) Using a 50 mm radius line angle of 7.5 °, etc.), yarn was produced by a conventional method to obtain a standard fineness of 11 dtex, 8 filament nylon 6 multifilaments, and 6 yarns.

As a result of measuring the fineness of nylon 6 multifilament and 6 threads, the fineness difference was 2% or less (○ judgment). That is, it can be seen that there is no quality difference between the single yarns spun from between the discharge holes because they are repeatedly merged in the merging plate five times and arranged in the discharge holes in a uniform state. In addition, the yarn breakage in 1 ton production was 0.5 times (○ judgment), and the yarn-making property was good.

[Example 2]
Nylon 6 chips with a relative sulfuric acid viscosity of 2.73 were melted at 285 ° C., and a plurality of filter media (filter sand), filters, perforated plates, and multi-stage confluence microchannels shown in FIG. 1 were formed at a discharge rate of 22.5 g / min. A pack mouthpiece for melt spinning in which existing merging plates and caps are arranged in order (number of discharge holes 48, number of threads 6, number of multi-stage merging fine flow paths 48, number of merging stages for one multi-stage merging microchannel, 5 stages of merging plate thickness) Using a 30 mm, radius line angle of 7.5 °, etc.), yarn was produced by a conventional method to obtain a standard fineness of 11 dtex, 8 filament nylon 6 multifilament, and 6 yarns.

As a result of measuring the fineness of nylon 6 multifilament and 6 threads, the fineness difference was 2% or less (○ judgment).

In addition, the yarn breakage in 1 ton production was 0.2 times (○ judgment), and the yarn-making property was good. Since the thickness of the merging plate is thinner than that of Example 1, the residence time of the polymer is shorter than that of Example 1, thread breakage is suppressed, and the yarn-making property is improved.

[Example 3]
Nylon 6 chips with a relative sulfuric acid viscosity of 2.73 were melted at 285 ° C., and a plurality of filter media (filter sand), filters, perforated plates, and multi-stage confluence microchannels shown in FIG. 1 were formed at a discharge rate of 22.5 g / min. A pack mouthpiece for melt spinning in which existing merging plates and caps are arranged in order (number of discharge holes 48, number of threads 6, number of multi-stage merging fine flow paths 48, number of merging stages for one multi-stage merging microchannel, 5 stages of merging plate thickness) Using a 2 mm radius line angle of 7.5 ° equal distribution), yarn was produced by a conventional method to obtain a standard fineness of 11 dtex, 8 filament nylon 6 multifilament, and 6 yarns.

As a result of measuring the fineness of nylon 6 multifilament and 6 threads, the fineness difference was 2% or less (○ judgment).

In addition, there was no thread breakage in 1-ton production (○ judgment), and the thread-making property was good. Since the thickness of the merging plate is thinner than that of Examples 1 and 2, the residence time of the polymer is the shortest, no yarn breakage occurs, and the best yarn-making property is shown.

[Comparative Example 1]
Pack base for melt spinning (number of discharge holes 48, number of yarns 6, 1-hole confluence plate thickness) having a configuration according to Patent Document 1 in which a filter medium (filter sand), a filter, a perforated plate, a single-hole confluence plate, and a base are arranged in this order. The yarn was spun in the same manner as in Example 1 except that 30 mm) was used to obtain nylon 6 multifilament with a standard fineness of 11 dtex, 8 filaments, and 6 yarns.

As a result of measuring the fineness of nylon 6 multifilament and 6 threads, the fineness difference exceeded 3% (× judgment). That is, unlike the pack mouthpiece that merges a plurality of times of the present invention, it is arranged in each discharge hole after being merged once in the merging plate, so that viscosity unevenness occurs due to the difference in thermal history of the polymer, and each discharge hole. It is considered that there is a quality difference between the single yarns spun from between. Thread breakage in 1 ton production exceeded 1 time (x judgment). In the one-hole merging plate, the polymers of all the flow paths are integrated into one hole and then guided to each discharge hole, so the length of the polymer flow path becomes long and the residence time increases, causing thermal deterioration of the polymer. Conceivable.

[Comparative Example 2]
A pack mouthpiece for melt spinning (number of discharge holes 48, yarn) having a structure according to Patent Document 1 in which a filter medium (filter sand), a filter, a perforated plate, a one-hole confluence plate on which a stationary kneading element is formed, and a mouthpiece are arranged in order. Threads were produced in the same manner as in Example 1 except that the number of threads was 6 and the thickness of the one-hole confluence plate was 100 mm) to obtain nylon 6 multifilaments with a standard fineness of 11 dtex, 8 filaments, and 6 threads.

As a result of measuring the fineness of nylon 6 multifilament and 6 threads, the fineness difference exceeded 2% (× judgment). That is, unlike the pack mouthpiece that is merged a plurality of times of the present invention, it is considered that the polymer is made uniform by the static kneading element, but it is arranged in each discharge hole after being merged once in the merging plate. Therefore, it is considered that the viscosity unevenness occurs due to the difference in the thermal history of the polymer, and the quality difference between the single yarns spun from each discharge hole occurs. Thread breakage in 1 ton production exceeded 2 times (x judgment). It is considered that the thickness of the one-hole confluence plate in addition to the uneven viscosity causes the residence time to increase due to the increase in the length of the polymer flow path, which causes further thermal deterioration of the polymer.

1: Spinning pack mouthpiece 2: Polymer introduction hole 3: Filter layer part 4: Filter material 5: Filter 6: Perforated plate 7: Confluence plate 7a: Multi-stage merging fine flow path 7b: Inner layer part Multi-stage merging fine flow path hole group 7c: Outer layer Multi-stage merging fine flow path hole group 7d: Multi-stage merging fine flow path group 8: Base 8a: Discharge hole flow path 9: Discharge hole 10: Confluence plate Radius line 11: Angle between radius lines

Claims (3)

In the pack mouthpiece for melt spinning in which the filter sand, filter, perforated plate, merging plate, and mouthpiece for spinning the thermoplastic molten polymer are arranged in this order.
The merging plate has a plurality of flow path holes in the upstream portion in the direction of the polymer spinning path, and the flow path holes merge multiple times as the flow path holes move toward the downstream in the direction of the polymer spinning path, and one flow path hole is located at the most downstream. Multiple multi-stage merging microchannels are formed, and the flow path volume of each multi-stage merging microchannel is the same. One flow path hole located at the most downstream in the direction of the polymer spinning path of the flow path is a pack mouthpiece for melt spinning that communicates with each discharge hole of the mouthpiece. The pack mouthpiece for melt spinning according to claim 1 , wherein the plurality of flow path holes in the upstream portion of the multi-stage merging fine flow path in the direction of the polymer spinning path are formed on the radial line of the merging plate. The pack base for melt spinning according to claim 1 or 2 , wherein the thickness of the merging plate is 2 mm or more and 60 mm or less.

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