JPS605537B2 - Glass fiber chopped strand cooling method and device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method and apparatus for cooling a hot chopped strand of glass fibers after drying the wet chopped strand.

Recently, glass fiber-reinforced thermoplastic resin products have been widely used as materials for various high-temperature parts.

These glass fiber-reinforced thermoplastic resin products are generally produced by pelletizing a mixture of thermoplastic resin pellets and chopped glass fiber strands using an extruder, and molding the resulting pellets containing glass fibers using an injection molding machine or the like. Manufactured by Chopped strands of glass fiber, which are the reinforcing material for such glass fiber-reinforced thermoplastic resin products, are made by spinning glass fibers from bushings and winding them into strands, or by pulling the strands together to form rovings in a wet state. Either the wet glass fibers are fed directly to the cutter as strands without winding, cut to the desired length, and then dried. Manufactured by

Generally, wet chopped strands are dried by supplying hot air from above the chopped strands deposited on a conveyor or a container. Therefore, after drying, the chopped strands are heated to a high temperature (for example, about 100 qo). ). For this reason, a cooling step for the high-temperature chopped strands is required, and conventionally the chopped strands from the dryer are placed in a flat container and left as is to perform so-called static cooling. However, ``the conventional static pupil cooling method requires an extremely long time for cooling (for example, 5 to 6 hours) and is extremely inefficient.Furthermore, conventional static pupil cooling only performs cooling; The fluff and fluff in the chopped strands cannot be removed, so in order to obtain high-density chopped strands, the chopped strands must be passed through a fluff removing device after cooling. Since the static cooling method is a batch type, it is difficult to connect it to the drying process and automate it.The present invention aims to solve these drawbacks of the prior art, and is extremely effective compared to the conventional static cooling method. To provide a method and device for cooling chopped strands, which can be continuously cooled in a short time and can remove fuzz, fluff, etc. from the chopped strands at the same time as cooling.

According to the first invention of the present application, a group of chopped strands is transported in a thin layer while giving a cascading action, cooling air is blown onto the chopped strand layer being transported from below, and the chopped strands are A method for cooling chopped glass fiber strands is provided, which comprises cooling through layers.

Furthermore, according to the second invention of the present application, there is provided a casing having a strand supply port at one end and a strand discharge port at the other end, and a porous hole arranged substantially horizontally in the casing and extending from the strand supply port to the strand discharge port. rectifier plate,
a cold air distribution chamber formed below the porous current plate; a cold air supply device that supplies cold air to the cold air distribution room; an exhaust chamber formed above the porous current plate; There is provided a glass fiber chopped strand cooling device characterized by having a transfer means for transferring the strands supplied onto the current plate toward the strand discharge port while deforming the strands.

Hereinafter, preferred embodiments of the present invention will be described in detail as illustrated in the accompanying drawings.

It should be noted that these Examples are merely for illustration of the present invention and are not intended to limit the present invention. In FIGS. 1 and 2, the chopped strand cooling device, designated as a whole by reference numeral 1, has a casing 2. A strand supply port 3 is provided at one end of the casing 2, and a strand discharge port is provided at the end of the casing 2. An outlet 4 is formed.

Inside the casing 2, a porous rectifying plate 5 is arranged substantially horizontally. The porous baffle plate 5 extends from the strand supply port 3 to the strand discharge port 4, and divides the inside of the casing 1 into a cold air distribution chamber 6 below the porous baffle plate 5 and an exhaust chamber 7 above the porous baffle plate 5. Further, the porous rectifier plate 5 has 1 to 5, preferably 2 ribs in diameter distributed almost uniformly over almost the entire surface of its cooling region with a porosity of about 1.5 to 10%, preferably about 2 to 3%. It has ~3 through holes 5A. The cooling distribution chamber 6 has a cold air entrance 8 on its side, and a cold air supply device 10 is connected to the opening □8 via a canvas duct 9.

The cold air supply/mixing device 10 includes a blower 10A, a damper (not shown), a filter (not shown), etc., and functions to suck in outside air and supply it to the cold air distribution chamber 6. If necessary, an air cooler may be provided within the cold air supply device. On the other hand, the exhaust chamber 7 has an exhaust 〇1 1 above it, and an exhaust duct 1 is connected to the exhaust low 1 via a canvas duct 12.
3 is connected. The exhaust duct 13 is, for example, a Siku.
It is connected to an exhaust system (not shown) having a dust collector, damper, and exhaust fan, such as a dust collector. Casing 2
is connected to the support column 1 via a vibration absorbing device 14 such as a spring.
5, and can vibrate together with the internal porous rectifying plate 5.

A vibration generator 16 is attached to the side surface of the casing 2 to vibrate the casing 2 and the porous rectifying plate 5. The vibration generator 16 vibrates the porous rectifying plate as described above, thereby forming the strands 17 supplied from the strand supply port 3 into a thin strand layer 18 on the porous rectifying plate 5, and passing the strands through the strand discharge port while hawking. 4. Therefore, the vibration generator 16 constitutes a strand conveying means. As the vibration generator 16, a known device can be used, such as an electromagnetic vibration generator that generates vibration by causing parallel reciprocating motion in a spring using an electromagnet, or a mechanical type that generates vibration by circular motion using an unbalanced rotating weight. A vibration calendar is preferred. A conveyor 20 for conveying the chopped strands from the drying device is provided near the strand supply port 3 of the chopped strand cooling device 1, while a known sorting device 30 and a metal sorting device 30 are provided near the strand discharge port 4. A removal device 31, a product storage container 32, and a removal container 33 are arranged.

Next, the operation of the above device will be explained. The high temperature chopped strands conveyed by the conveyor 20 are supplied onto the porous rectifying plate 5 from the strand supply port 3 of the cooling device 1.
Since the porous rectifying plate 5 is vibrated by the vibration generator 16, the chopped strands on the porous rectifying plate 5 form a thin strand layer 18 while jumping, and are naturally and continuously transferred toward the strand discharge port 4. be done. For proper layering and transport of such chopped strands,
The porous rectifying plate 5 preferably has a voltage of about 500 to 3000 Hz, preferably about 1
000 to 2000 days 2 frequency and number side, for example 1.5 to
It is appropriate to vibrate with an amplitude on the 3.0 side. In addition,
Depending on the amount of chopped strands supplied and the cooling air jet velocity, effective stratification and transport can be achieved with values outside the above range. On the other hand, the cold air supply device 1 supplies cold air to the cold air distribution chamber 6, and this cold air is ejected upward through the through holes 5A of the porous rectifier plate 5, passes through the strand layer 18 on the porous rectifier plate, and becomes chopped strands. to cool down.

The chopped strands are transported by the vibration of the porous rectifier plate 5 while jumping and being hawked, so that all the chopped strands are uniformly blown with cold air and extremely quickly. , and cooling is performed uniformly. Although the blowing speed of the cold air is not particularly limited, it is preferably selected so as to slightly float the chopped strands on the porous rectifying plate and exert a mixing effect on them. For good cooling, the layer thickness of the chopped strands should be approximately 0.5 to 10 mm thick, preferably about 1 to 8 mm thick. The jetting rate of the cooling air is approximately 1 to low per second, preferably about 4 to 6 skins per second. The cold air that has passed through the chopped strand layer 18 cools the chopped strands, removes fluff, fluff, etc. attached to the chopped strands, and enters the exhaust chamber 7 with them. , exhaust row 1, exhaust duct 1
It is discharged through 3.

The chopped strands cooled and fluff removed on the porous rectifying plate 5 are dropped from the strand outlet 4 into the sorting device 30, and miscut chopped strands and other defective chopped strands are sorted out as waste. The metal is sent to the removal container 33, and the rest is sent to the product storage container 32 via the metal removal device 31. In the above embodiment, the porous rectifying plate 5
are arranged almost horizontally, but if it is possible to transport the chopped strands, it may be arranged at a slight inclination.

In addition, as the porous current plate 5, a plate material with a large number of circular through holes 5A is used; however, the present invention is not limited to this, and a plate material with a large number of elongated through holes may also be used. Furthermore, in the above embodiment, the porous rectifying plate is vibrated as a means for transporting the chopped strands while hawking them, but the present invention is not limited to this, and can be modified as appropriate. It is.

3 and 4 show an embodiment using a chopped strand conveying means different from those in FIGS. 1 and 2, and in this embodiment, the casing 2 and the porous rectifying plate 5 are The vibration generator 1 shown in FIG.
6 is not used. Instead, a rotary transfer device 40 is provided above the porous rectifying plate 5. This rotary transfer device 40' is an endless belt 4 with a large number of pins 41 installed as a shield.
2, and the movement of the belt 42 causes the pin 41 to plunge into the chopped strand layer 18, moving the chopped strand while moving. This belt 42 allows the air ejected from the porous rectifying plate 5 and passed through the strand layer 18 to pass through it well, and for example, a chain belt is used. Instead of an endless belt 42, the rotation has radial pins 44, as shown in FIG. A large number of controllers 45 may be provided. In these embodiments as well, while the chopped strands are being transported while being cut open, cold air is blown from below to quickly cool them and remove the fluff. As explained above, according to the present invention, the high-temperature chopped strands after drying are formed into a thin layer, transferred while giving a fly attracting effect, and cooling air is blown from below to the chopped strands. By passing through the layers, the cooling air uniformly contacts all parts of the chopped strands, resulting in extremely rapid and uniform cooling.

Moreover, since the cooling air also has the effect of removing fluff from the chopped strands, the fluff content in the cooled chopped strands is extremely low, and high-quality chopped strands can be obtained. There is no need to pass through a fluff removal device as in the case of Furthermore, since continuous cooling is possible in the present invention, it has the advantage that it can be automated in combination with a conventional continuous drying device. The specific effects of cooling according to the present invention will be shown below using experimental examples.

Experimental Example 80 From a bushing equipped with a nozzle plate having a tip nozzle made by Kawabata, a filament of diameter 1 mm was spun, collected and wound according to a conventional method, and the package was dried to obtain a stride dry cake.

Each strand is pulled out from the dry cake 7, put together and coated with water, then fed into a regular cutter and cut into 3 lengths, and the resulting wet chopped strand is placed directly under the cutter. It was deposited on a conveyor provided and then continuously dried by running it in a hot air dryer at 130°C. Drying time is 2 hours.
The chopped strands coming out of the dryer are conveyed and supplied to the cooling device 1 by a conveyor 20' extending to the cooling device 1 shown in FIG. It was cooled down and taken out as a product. In this cooling process, the supply rate of the chopped strands was approximately 85 k9/hr, and the layer thickness of the chopped strands on the multi-hole rectifying slope was approximately 50 to 6 k9 under the cooling air jetting conditions described below. . In the cooling device 1,
The porous rectifying plate 5 has a size of 40 mm wide x 1500 mm wide, and has small holes 5A of 2 diameters uniformly distributed over its entire surface with an open area ratio of 3%.

The vibration conditions of the porous rectifier plate were a frequency of 1450 days and an amplitude of 2 to 3 degrees, and the vibration was generated by the mechanical vibration generator described above. Room temperature air was used as the cooling air for cooling the chopped strands on the porous rectifier plate, and the jet speed from the small holes of the porous rectifier plate was set to about 5 m/sec.
Table 1 shows the cooling time and the percentage of fluff removed when cooling was performed according to this specification, and Table 2 shows the characteristics of the chopped strands obtained. For comparison, the dried chopped strands that had passed through the dryer were cooled in a conventional container, and the chopped strands were cooled in a container and cooled, and the chopped strands were further cooled through a conventional wind ray removal device. The case where wind line removal processing is performed is also shown. Note that the removed wind ray rate in Table 1 is expressed as the ratio of the removed wind ray amount to the amount of chopped strands to be processed.

The high specific gravity in Table 2 was expressed by adding 200 mm chopped strands uniformly into a 1000 mm measuring cylinder, reading the volume, and expressing it in terms of numbers.

Experience has shown that the larger the bulk specific gravity, the less fluff and the higher the density of the product. The flow value is a chopped strand with a value of 500 mm, and the length of one side of the entrance part is 20 arcs and the height is 1
Put the chopped strands into a pyramidal hopper with 5 skins, open the 2.5 skin square outlet under the vibration of 3000 Hz and 2 skin amplitude at the entrance, and all the chopped strands will fall and be discharged from the hopper outlet. It is expressed in seconds/500 evenings.

The smaller this value is, the less fluff there is, meaning that it is a high-density product. The fluff content is the ratio (%) of the original weight of the fine filaments and strands separated by dropping the chopped strands from the same hopper as above and blowing air from the side during the fall. It means less fiber.

Table 1 Table 2 From the above results, it will be understood that the cooling time in the embodiment of the present invention was much shorter than in the conventional static calendar cooling.

Moreover, the obtained product is extremely superior in fluidity value and fluff content compared to products that have only been subjected to conventional stationary cooling, and is also superior to products that have been subjected to fluff removal. Further, in the above example, although the fluff content was lower than that in the case where the fluff removal operation was performed, the removed wind ray rate was small. This indicates that in addition to monofilament fly fluff, relatively thin strands that are effective as products were also removed in the secondary fluff removal operation.
Therefore, in the embodiments of the present invention, the product yield is also improved.

[Brief explanation of the drawing]

FIG. 1 is a side sectional view showing one embodiment of the present invention, FIG. 2 is a partially sectional front view of the embodiment shown in FIG. 1, and FIG. 3 is different from the embodiment shown in FIG. 1. Fig. 1 and a side cross-sectional view of the same aircraft show another embodiment, Fig. 4 is a front view showing a partial cross section of the embodiment of Fig. 3, and Fig. 5 shows a rotation of the embodiment of Fig. 3. FIG. 7 is a side view showing a modification of the transfer device. 1... Cooling device, 2... Casing, 3...
... Strand supply port, 4 ... Strand discharge port, 5 ... Porous rectifying plate, 5A ... Through hole, 6 ... Cold air distribution chamber, 7. ...exhaust chamber,
10...Cold air supply device, 16...Vibration generator, 17...Chopped strand, 18.
...Strand layer, 40...Rotary transfer device. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5

Claims (1)

[Scope of Claims] 1. A group of chopped strands is transferred in a thin layer while being stirred, cooling air is blown onto the layer of chopped strands being transferred from below, and the chopped strands are A method for cooling chopped glass fiber strands, characterized by cooling the chopped strands by penetrating the layers. 2. A casing having a strand supply port at one end and a strand discharge port at the other end, a porous rectifier plate disposed approximately horizontally within the casing and extending from the strand supply port to the strand discharge port, and a cold air distribution chamber formed below; a cold air supply device that supplies cold air to the cold air distribution chamber; an exhaust chamber formed above the porous current plate; and a strand supply port that supplies cold air onto the porous current plate. A cooling device for chopped glass fiber strands, comprising a transfer means for transferring the chopped strands toward the strand discharge port while stirring the strands. 3. The glass fiber chopped strand cooling device according to claim 2, wherein the transfer means is a vibration generator that vibrates the porous rectifying plate. 4. The transfer means comprises a rotary transfer device disposed above the porous rectifier plate, and the rotary transfer device plunges into the chopped strand layer on the porous rectifier plate and transfers the chopped strands. The glass fiber chopped strand cooling device according to claim 2, characterized in that it has a large number of moving pins.