JPH04164838A - Production of chopped strand - Google Patents

Abstract

PURPOSE:To prevent the lowering of productivity and quality of strand caused by the thermal imbalance of a bushing induced by the breakage of a strand by providing a glass fiber chopping device for each one of plural spinning furnaces. CONSTITUTION:Glass fibers spun by plural spinning furnaces are collected and immediately cut to obtain chopped strand. Each spinning furnace (e.g. bushings 10a, 10b, 10c) is provided with one chopping device (e.g. 20a, 20b, 20c) and the obtained wet chopped strands (e.g. 30a, 30b, 30c) are dried (50). The wet chopped strands are charged into a dryer 50 preferably by a vibration transfer apparatus (e.g. 40a, 40c) having a though for the vibration transfer of chopped strands at a trough-inclination angle of 20-60 deg., a vibration frequency of 1200-1600 Hz and a vibration amplitude of 0.2-3mm.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for producing chopped glass fiber strands by spinning molten glass, applying a coating agent, and cutting the molten glass immediately after convergence.

[Prior art] Conventionally, a strand formed by gathering glass fibers pulled out from a spinning furnace and coated with a coating agent is not wound up and dried (but immediately cut to produce chopped strands). A manufacturing method called direct cut is used.

FIG. 2 shows a conventional example of such a manufacturing method.
It is disclosed in the publication No.-163136.

In the conventional production of chopped glass fiber strands by direct cutting, it is believed that reducing the number of equipment used in the cutting and drying process of strands containing a large number of filaments will lead to improved efficiency and lower costs. Several strands drawn from the spinning furnace are cut using one large cutting device.

The manufacturing process involves applying a coating agent to the glass fibers pulled out from multiple spinning furnaces using an applicator mechanism installed below the spinning furnace, converging them into strands, and passing these multiple strands through a guide mechanism to feed rollers. The strand is stretched and cut into chopped strands of a certain length by a cutter roller, which is a known cutting device, and is pressed against the surface of the feed roller. The cut wet chopped strands are conveyed on a belt conveyor,
Alternatively, the product is transported to a drying device or storage container using a vibrating conveyor, etc., and is then dried as a product.

[Problems to be Solved by the Invention] However, there are various problems with the manufacturing method in which a plurality of strands are cut using one large-sized cutting device to obtain chopped strands.

For example, breakage of glass fiber strands occurs at the nozzle part, the coating agent application roller part, and the glass fiber strands are also cut by winding around the guide, sample measurement, and the like.

At this time, the thermal balance is disrupted at the nozzle surface of the spinning furnace that broke, and even when spinning is restarted, the diameter of the filament that is drawn out increases, and a product of desired quality cannot be obtained immediately, and this portion is discarded. In addition, reconnecting broken strands is dangerous under high-speed operation, so the cutting equipment must be stopped or rotated at low speed. The amount of fiber drawn out is also the same as that of the spinning furnace that broke, and the same thermal history fluctuation occurs, and the fiber diameter changes in all the strands from the spinning furnace, resulting in poor quality and a problem with the product quality. Not.

However, when a spinning furnace and a cutting device are combined as one set as in the present invention, the effect of breakage is limited to that spinning furnace.
- Even if one spinning furnace stops, other spinning furnaces are unaffected and can produce products of good quality. As a result, not only the lost operation time but also the amount of inferior quality products are significantly reduced.

Further, the number of glass fiber filaments constituting the chopped strand is usually about 800 to 2,000. Therefore, for example, when strands spun from a 3,000-hole bushing attached to each spinning furnace are collected and cut simultaneously, the cutting device section divides the strands into 6 to 10 strands and cuts them. necessarily become wider and larger.

When cut wet chopped strands are fed into a drying device or storage container using a conveyor, vibrating conveyor, etc. that is commonly used as a conveyance means, the wet chopped strands adhere to the belt or trough, and the adhering material peels off and becomes part of the product. This can cause problems such as stains appearing on the surface of glass fiber-reinforced plastic products.

The present invention aims to prevent a decrease in production volume and quality caused by thermal imbalance in the bushing part due to strand breakage that occurs in the chopped strand manufacturing process using the direct cut method, and to prevent product deposits from adhering to the conveying device. The purpose is to prevent contamination.

[Means for Solving the Problems] The present inventor has considered various methods to solve these problems, but the method of cutting multiple strands coming out of multiple spinning furnaces with one large cutting device is the most efficient method. Contrary to the common sense that it is a common idea that a single cutting device is attached to multiple spinning furnaces to cut and dry glass fiber strands, these problems can be solved and productivity and product quality can be improved. The present invention was completed after various studies under the heading.

In the present invention, for example, as shown in FIG. 1, one unit of the chopped strand manufacturing apparatus includes a bushing 10a, a coating agent application roller 12a, a focusing roller 13a, and a cutting device 20a.
The surface of the guide roller 21a1 is rubber; the feed roller 22a is made of synthetic resin and can rotate freely.
, a cutter roller 23a which is in pressure contact with the feed roller 22a and is driven by a motor and has a large number of cutter blades protruding radially from the surface thereof, and other components necessary for spinning, such as a chopped strand vibration conveyance device 40a. It consists of additional equipment not shown. These equipments may be the same as those used in the conventional direct cutting method, and the cutting device 20a includes a guide roller 2
Since the 1a1 feed rollus 2a1 cutter roller 23a can be made narrow and small, the entire apparatus becomes a compact facility.

The operation of these facilities is as follows.

The glass fibers pulled out from the bushing 10a are coated with a coating agent (sometimes referred to as a sizing agent or sizing agent) by a coating roller 12a, and then divided into the required number of glass fibers, which are then bundled by a converging roller 13a into strands. 14a.

The strand 14a passes through a guide roller 21a and is wound around a feed roller 22a. Feed roller 22
A is rotated by a cutter roller 23a which is pressed, and the glass fiber drawn out from the bushing 10a is stretched, and the strand 14a is cut into a length determined by the distance between the cutter blades by the cutter blade biting into the surface of the feed roller at the pressure contact point. A pud strand 30a is formed. Chopped strands 30a typically contain about 10-15% water by weight based on the glass fibers.

The other two sets of production equipment shown in Figure 1 are operated in a similar manner, and in this figure the wet chopped strands produced from the three sets of glass fiber strand production equipment are collected into one set. Although the case where the glass fiber chopped strands are put into one drying device is shown in the example, it is also possible to further increase the number of production facilities for the chopped glass fiber strands.

Since the glass fiber strands from each spinning furnace are cut by separate cutting devices, the resulting wet chopped strands must be fed into the drying device 50 from the input port 51 by some conveying means for drying. As the conveyance device and drying device, known devices such as a belt conveyor and an aeration drying device can be used. However, in the present invention, it is preferable to use a vibration conveying device as described below as the conveying device, thereby preventing the glass fibers or coating material from adhering to or accumulating on the conveying device and being mixed into the product, resulting in higher quality products. products can be obtained.

A vibratory conveying device installed at the bottom of the cutting device 20a, in which the installation angle of the trough is 20-60 degrees, the frequency is 1200-1600 H2, and the amplitude is 0.2-3 mm for vibrating and conveying the equally wet chopped strands. 40a, the wet chopped strands 30a that fall after cutting are fed into the vibration drying device 50 through the feeding port 51 without being deposited.

If the trough attachment angle is less than 20 degrees, the fibers will adhere to the trough, and if it is greater than 60 degrees, the wet chopped strand, which is an aggregate of filaments, will undergo a "slip" phenomenon, resulting in poor morphology, which is undesirable.

If the frequency is low, the fibers will stick to the trough, and if the frequency is high, the wet chopped strands will easily come apart. In addition, if the amplitude is less than 0.2 mm, there will be a problem with the conveying ability;
Above this, the wet chopped strands tend to come apart.

Although the shaking and conveying device may be individually vibrated by a known vibrating means, it is effective to downsize the device if the vibration source is shared with the vibrating aeration drying device.

One vibration drying device 50 is attached to each of the plurality of chopped strand manufacturing devices.

Example An embodiment of the present invention will be described below with reference to FIG.

A glass fiber filament with a fiber diameter of 13 μm is pulled out from a bushing with a 2800-hole nozzle and coated with an Evokin resin binder using a coating roller, and is divided into three by a converging roller below the coating roller, each having approximately 900 glass fiber strands 3. Introduced to the book cutting device and 1100m/
Cut the strand into chopped strands with a length of 3 mm while pulling at a speed of 3.0 mm.

Chopped strands of similar bushings are manufactured in the same manner, and these three bushings are made into one manufacturing unit, and a vibrating ventilation drying device is placed directly below the central bushing. This vibrating ventilation drying device was placed directly below the cutting device located in the center, and vibrating troughs were installed below the cutting devices located on the left and right sides as conveying devices for feeding the wet chopped strands into the drying device. The vibrating trough has a length of 660 mm and a width of 240 mm, and is installed at an angle of 30 degrees below the horizontal direction at the input port of the drying device.The rotary vibrators installed on the left and right sides of the drying device have the same amplitude of 2 mm as the vibrating ventilation drying device. Frequency 145
It was vibrated at 0Hz.

The wet chopped strands with a moisture content of 12% by weight, which were cut by the cutting devices located on the left and right sides of the drying device, were fed into the drying device without falling and accumulating in the vibrating trough installed 1000 mm below the cutting point. Also, the wet chopped strands cut by the cutting device located directly above the drying device were input from directly above the drying device.

The drying device is a vibration/ventilation type, with a porous rectifier plate having a porosity of 3%.
The amplitude was 2 mm, the frequency was 1450 Hz, the air velocity through the small hole was 5 m/sec, and the heated air temperature was set at 160°C.

The wet chopped strands supplied from each cutting device had a weight of 60 kg/hr, and were dried, cooled, and taken out as a product.

Comparative Example The glass fiber strands pulled out from three bushings were collected and cut by one large cutting device, and after the strands were broken, the cutter operation was stopped and the reconnection was carried out.
Other conditions were the same as in the examples.

Table 1 shows the results of measuring the number of breaks, product yield, and chopped strand characteristics of Examples and Comparative Examples.

As can be seen from this result, the product yield is good despite the fact that the number of breaks is greater than that of the conventional method.

It has a high bulk density and good fluidity.

U effect In the present invention, a cutting device is installed for each spinning furnace, so unlike conventional manufacturing methods, the spinning furnaces that stop cutting are limited to those where the glass fiber has broken, and other spinning furnaces are not used. Since production can be carried out continuously in the furnace without being affected by this, the product yield is improved, and since the number of strands to be cut by - cutter rollers is small, the cutting device can be downsized, allowing narrow spinning. The working environment can be improved.

Furthermore, since the installation angle and amplitude of the vibrating trough are set to specific conditions, there is no accumulation of glass fibers or coating material adhering to the trough, and no deposits are mixed into the product.

Table 1 Note 1 = Product yield; Product yield/Theoretical yield (Spinning amount Open the fibers.

After the rotation has stopped, take out the sample inside the container and sieve it using a 2.5 mesh standard sieve. good.

Note 3: Upper opening is 20x20cm, lower opening is 2-5
A vibration of 300 Hz and an amplitude of 2 mm is applied to the upper part of a pyramid-shaped hopper measuring 2.5 cm x 15 cm in height, 100 g of chopped strand is introduced, and the time until it is completely discharged is measured. Discharge per second Expressed in grams, the larger the better.

[Brief explanation of the drawing]

FIG. 1 is a front view of an embodiment of the present invention. The second figure is a front view of the conventional manufacturing method. 10a...Bushing 20a...Feed roller (lower part of spinning furnace) 23a...Cutter roller 11a
...Filament 30a...Moist chopped 12
a... Application roller strand 13a...
・Focusing roller 40a... Vibration conveyance device 14a...
- Strand 50... Drying device 20a... Cutting device 51... Input port 21a... Guide roller 52... Rotary type % type %

Claims (1)

[Claims] 1) In the production of chopped strands in which glass fibers are spun from a plurality of spinning furnaces, bundled, and immediately cut, one cutting device is disposed in each spinning furnace, and the resulting wet chopped strands are Method for producing chopped glass fiber strands characterized by drying 2) The installation angle of the trough for vibrationally conveying the wet chopped strands is 20-60 degrees, and the frequency of vibration is 1,200-1.
2. The method for producing chopped glass fiber strands according to claim 1, wherein the chopped glass fiber strands are fed into the drying device using a vibrating conveying device having a vibration frequency of 0.2 to 3 mm at 600 Hz and an amplitude of 0.2-3 mm.