JPH06254853A - Manufacture of filament reinforced synthetic resin strand - Google Patents

Abstract

PURPOSE:To impregnate filaments with a molten resin as completely as possible by installing an optional number of rollers, which contact the filaments by crossing the track of the running filaments, in a molten resin container in which the filaments are impregnated with the resin and drawing resin impregnated filaments while the rollers being rotated forcedly. CONSTITUTION:A roving 3a led from an inlet nozzle 4 to an impregnation head (molten resin container) 1, after passing through opening and impregnating rollers 6 one after another, is drawn toward an outlet nozzle 5 through a guide roller 7 and a converging roller 8. The opening and impregnating rollers 6 are rotated forcedly. In this way, a high viscosity molten resin is led to the press-contacting part of the roving 3a along with the rotation of the rollers 6 to improve the impregnation with the resin. The rollers 6 are preferably arranged oppositely to hold the roving 3a between them with at least one roller rotated forcedly. Moreover, the roving 3a is preferably drawn while a resin impregnated roving 3b being twisted in order to reduce troubles caused by fluff in the roving 3a.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for efficiently producing a strand-shaped synthetic resin material reinforced with long fibers. The above strand-shaped material can be used as it is, but can also be used after being cut to an arbitrary length according to the purpose of use. An example of the latter is a pellet material used as a raw material for injection molding, injection compression molding, compression molding, etc. In this case, cutting into a length of several mm to a dozen mm is used. It is common. In the present specification, the former is classified as a long fiber reinforced synthetic resin strand (hereinafter sometimes simply referred to as a long fiber strand), and the latter is classified as a long fiber reinforced synthetic resin pellet (hereinafter sometimes simply referred to as a long fiber pellet).

[0002]

2. Description of the Related Art When it is desired to produce a molded product having a desired shape by injection molding a fiber-reinforced resin material, for example, a pellet-shaped raw material containing a reinforcing fiber in a synthetic resin is used.
Reinforcing fibers contained in such pelletized raw material are generally short fibers, but in recent years, long fibers are impregnated with a synthetic resin in one direction, that is, the long fiber pellets have been developed to have high strength. It is evaluated as a raw material for manufacturing injection molded products.

As a method for producing these, a resin of a screw type or a plunger type extruder is provided on the side surface of an impregnation head in which reinforcing fibers (hereinafter sometimes referred to as rovings) are introduced in a bundle and run in an opened state. Impregnation is performed by providing a liquid discharge port and passing the roving through a molten synthetic resin bath formed by being press-fitted into the impregnation head. Then, the resin impregnated roving is taken out from the outlet nozzle of the impregnation head, and while curing the resin material, it is wound into the long fiber strands, which are cut into arbitrary lengths as described above, and the long fiber pellets are obtained. You can also do it.

The most basic requirement in carrying out the above method is to sufficiently impregnate the long fibers and the molten synthetic resin. In the conventional technique, a freely rotating type opening / impregnation is performed in the impregnation head. It has been practiced to provide a plurality of rows of application rollers, and to open the fibers to enhance impregnation by contacting the traveling roving bundle so as to press the rollers. However, since the molten resin is adjusted to a moderate temperature to avoid thermal decomposition, its viscosity is relatively high. Therefore, the impregnability as expected is not obtained even at the contact portion with the roller, much less between the roller and the roller as if the roving passes through the molten resin bath substantially. The section is a part where the progress of impregnation is hardly expected. Therefore, in the conventional impregnation head, either a large number of opening and impregnating rollers should be arranged along the loving traveling path, or the rollers should be arranged in a meandering manner and the tension applied to the roving should be increased to increase the contact pressure to the roller. Was devised. However, the former method does not provide a sufficient impregnation effect commensurate with the size of the impregnation head and the maintenance of the roller becomes troublesome, but the latter method increases the frictional resistance and cuts the roving. Had a problem that a part of the roving was cut off to cause fluffing. Although this fluffing will be described in detail later, due to the various circumstances as described above, a technique capable of sufficiently enhancing the impregnation property has not yet been developed.

The reinforcing fiber is not particularly limited in material, diameter, number of bundles, etc., and for example, glass fiber, carbon fiber, organic fiber, metal fiber, etc. can be freely selected. Also, the synthetic resin material is not limited, and it is said that either a thermoplastic resin or a thermosetting resin can be used.

[0006]

If the impregnation is insufficient, the long fiber strands and long fiber pellets produced will not be sufficiently joined to each other, causing the long fibers to come apart and fall off, resulting in poor handleability. To lower the molding workability.
In addition, when the long fibers are conductive, there is a risk of causing a short circuit accident in the power supply box. Furthermore, when a final product is manufactured using this material by, for example, an injection molding method,
The long fibers insufficiently bonded to the synthetic resin behave in a singular manner and become entangled to form pills, which impairs the moldability and causes a poor appearance of the molded product. Therefore, the most important object of the present invention is to establish a manufacturing technique that allows impregnation of long fibers and molten synthetic resin as completely as possible.

In addition to the above problems, it is also important to ensure continuous productivity in the method of continuously impregnating long fibers while running them. That is, production interruption due to occurrence of trouble is disliked as a reduction in productivity. However, in the actual production process, after the start of production,
Soon after, the take-up resistance of the long fibers increased, and sometimes the take-up became impossible in a few hours, leading to production interruption. In such a case, when the impregnation head is disassembled and inspected, in the impregnation head, the exit nozzle and the upstream side of the impregnation head are filled with a nodule of fibers (for example, a black nodule with a carbon fiber). The nodule is formed by winding an opening / impregnation roller arranged in the impregnation head. Therefore, in order to reuse the impregnating head, it is necessary to completely disassemble and clean it, and even if two or more sets of impregnating heads are prepared and used alternately, the productivity is extremely reduced. It had to be something.

Therefore, the present invention has decided to eliminate such inconvenience as a secondary problem, and studied a method capable of continuously taking up long fibers for a long time without any inconvenience.

[0009]

According to the method of the present invention which has been able to achieve the above object, an arbitrary number of rollers which intersect the running locus of long fibers and come into contact with the long fibers are arranged in a synthetic resin bath container. Then, the gist is to take the resin-impregnated long fiber while positively rotating the roller.

As a technique for achieving the above-mentioned secondary problem, it is possible to propose a method in which the resin-impregnated roving which is taken from the synthetic resin bath container is taken in a twisted state. Also, by imparting such a twist, the force that drives out the air bubbles in the fiber gap and forcibly moves it against the molten resin between the fibers works, so that the effect of enhancing the impregnation property of the resin is also demonstrated. To be done.

[0011]

In the present invention, the opening / impregnation roller against which the roving is pressed is not the free-rotating type as in the past but the positive-rotating type, so that the molten resin existing at the position distant from the roving running position is Due to its high viscosity, it is brought into the pressing contact portion as the roller surface rotates. Therefore, the roving is in a state where the molten resin is brought into the opening gap at the same time as the opening, but this action acts to exert a large resin pressure on the roving due to the high viscosity of the molten resin. To do. Therefore, the molten resin is positively pushed into the opening gap, and the impregnation property is improved at once. The active rotation direction of the fiber opening / impregnation roller is not particularly limited, and may be the direction of rotation against the running direction as long as it does not give a large running resistance to the roving, but the running resistance is possible. From the viewpoint of reducing the number, it is recommended to rotate in the same direction as the traveling direction and at a synchronized speed.

The opening and impregnating rollers may be arranged so as not to prevent the running locus of the roving from forming a straight line, but may be arranged in a zigzag pattern so as to positively meander. In particular, when the roller is synchronously rotated in the same direction as the roving running direction, the running resistance due to the contact pressure with the roller becomes very small, so even if the above-mentioned zigzag arrangement is performed, cutting or fluffing may occur. Is significantly reduced, which is one of the important advantages of the present invention.

Further, the rollers may be in contact with the traveling roving from only one direction or may be alternately contacted from both directions, but most preferably, the traveling roving is pressed from both sides so as to sandwich the traveling roving. In such an arrangement, by adjusting the gap between the opposed rollers, the roving can be opened and impregnated with a relatively light pressure contact force. That is, it becomes possible to improve the impregnating property without increasing the take-up resistance of the roving. In the case of such an opposed sandwiching arrangement, either both of the opposed rollers may be actively driven, or only one may be actively rotated and the other may be freely rotated. In the case of the former both positive rotation type, it is general that both of them are made to coincide with the roving traveling direction, but an implementation system in which one is made the same direction and the other is made the opposite direction is also included in the present invention.

Next, a means for solving the above-mentioned secondary problem will be described. The present inventors used an impregnation head made of a transparent material and investigated from various angles in order to investigate the cause of the fact that the take-up resistance of long fibers increased during continuous production and finally the take-up became impossible. As a result, fluffing occurs from the long fiber bundle due to friction or ironing during the process of passing through the fiber opening / impregnation roller or when being drawn from the exit nozzle of the impregnation head, and this fluff is attracted immediately before the exit nozzle. It was found that the nodules were entangled with each other, and these grew one after another in a short time to form the nodule.

Therefore, as a means for solving this, there are two possible ways to prevent the occurrence of fluffing and to devise so that the generated fluff is taken out of the impregnation head together with the take-up filament without any inconvenience. However, here we decided to take a solution in the latter direction. That is, in the present invention, the roving take-up member provided on the downstream side of the impregnating head is provided with a twist imparting mechanism (for example, a rotating mechanism), and the resin impregnated long fibers are twisted and taken up. When such a twist is applied, the twist is transmitted to the inside of the impregnation head through the outlet nozzle hole, and the fluff that starts to be entangled immediately before the outlet nozzle is taken into the twist and pulled out from the outlet nozzle. Is demonstrated. As a result, the formation of the nodule immediately before the exit nozzle is prevented, and even if continuous operation is performed for a long time, no trouble occurs in taking the resin-impregnated long fiber, and excellent productivity can be exhibited.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a side view explanatory diagram conceptually showing an apparatus for carrying out the present invention, and FIG. 2 is a plan view explanatory diagram. In these figures, 1 is an impregnation head (synthetic resin bath container), 2
Indicates a molten synthetic resin pressure inlet, and the roving 3a sent from the arrow A enters the impregnation head 1 from the inlet nozzle 4 and has a grooved opening / impregnation alternately arranged on one side across the traveling locus of the roving 3a. After passing sequentially through the application roller 6a and a normal fiber-opening / impregnation roller 6b having no groove (both of which are positive rotation type), the guide roller 7 and the convergence of these rollers arranged orthogonally to each other. It is taken out toward the outlet nozzle 5 through the roller 8 for use. On the other hand, since the molten synthetic resin pressed in from the molten synthetic resin pressure inlet I in the direction of the arrow M is filled in the impregnation head 1, the roving 3a receives the resin impregnation in the process of passing through the rollers and the outlet nozzle. The resin-impregnated roving 3b is taken out from 5 in the direction of arrow B. The supply amount of the roving 3a and the press-fitting amount of the molten synthetic resin are controlled so as to keep a balance, but when the latter becomes excessive, it is pushed out in the direction of arrow N in FIG.

As the grooved opening / impregnation roller 6a,
In addition to the flat roller type as shown in the figure, a drum type roller type having a large axial center portion may be used, but in the present invention, it is a positive rotation type, which results in an excellent opening / impregnation effect. can get. Incidentally, FIG. 3 shows the facing arrangement type described above, and the flat roller type is preferably used here, and the presence or absence of the groove can be freely selected.
In any case, with such a positive rotation roller, a sufficiently satisfactory degree of impregnation was achieved. As a result of obtaining such good impregnability, fluffing of the fiber is reduced, the supplyability in the process of manufacturing an injection molded product using the fiber is improved, and the measuring time in the injection molding machine is shortened and stabilized. Therefore, effects such as reduction of residence time and stability of physical properties and product dimensions were obtained.

Further, in the present invention, in order to further reduce the occurrence of troubles due to fluff, the following structure is added. That is, the resin-impregnated roving 3b which is taken out in the direction of the arrow B as described above is moved by the twist generator (not shown) to the arrow C.
The twist formed by the rotation is indicated by the arrow B.
And proceeds in the opposite direction to reach the converging roller 8. Therefore, in the resin-impregnated roving 3b, the twist is generated and grows from the downstream side of the converging roller 8 as a starting point. Therefore, the fluff that is generated in the impregnation head 1 and is attracted toward the outlet nozzle 5 as the roving 3a travels, or the fluff that is generated by the sliding friction with the outlet nozzle 5 is caught in the twist in the generation / growth process. The resin-impregnated roving 3b is drawn from the outlet nozzle 5 and is drawn out of the outlet nozzle 5 to produce a long fiber strand. Therefore, no fluff is left in the impregnation head 1 and no fiber agglomeration occurs.

[0019]

EFFECTS OF THE INVENTION Since the present invention is constituted as described above, the resin impregnating property becomes very good without increasing the take-up resistance of the roving. As a result, there was no loss of fibers and the resulting troubles in the molding process, and productivity was improved. Furthermore, it has become possible to stably manufacture a molded product having good physical properties without appearance defects such as fluffing. Even if the resin-impregnated long fibers are taken at a higher speed to cause fluffing, the long-fiber fluff is taken into the twist and taken out of the impregnation head. The entanglement of fibers does not grow inside. Therefore, it is possible to maintain excellent productivity for a long period of time without increasing the take-up resistance due to the agglomeration of the fibers or causing the take-off failure.

[Brief description of drawings]

FIG. 1 is a side view explanatory diagram of an apparatus for carrying out the present invention.

FIG. 2 is an explanatory plan view of an apparatus for carrying out the present invention.

FIG. 3 is a side view explanatory view showing another embodiment for carrying out the present invention.

[Explanation of symbols]

 1 Impregnation Head (Synthetic Resin Bath Container) 2 Molten Synthetic Resin Pressure Inlet 3a Roving 3b Resin Impregnation Roving 4 Inlet Nozzle 5 Outlet Nozzle 6 Fiber Opening / Impregnation Roller 6a Grooved Fiber Opening / Impregnation Roller 6b Fiber Opening / Impregnation Roller 7 Guide roller 8 Converging roller

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Claims (6)

[Claims] 1. A long fiber is aligned and introduced into a synthetic resin bath container, and the resin-impregnated long fiber is taken out from an outlet nozzle of the synthetic resin bath container while impregnating the long fiber with the synthetic resin. In the method for producing a long fiber-reinforced synthetic resin strand, in the synthetic resin bath container, an arbitrary number of rollers that intersect the running locus of the long fibers and come into contact with the long fibers are arranged, and the resin is positively rotated while the rollers are being positively rotated. A method for producing a long fiber-reinforced synthetic resin strand, which comprises collecting impregnated long fibers. 2. The method for producing a long fiber reinforced synthetic resin strand according to claim 1, wherein the rollers are arranged so as to face each other so as to sandwich the long fiber. 3. The method for producing a long fiber reinforced synthetic resin strand according to claim 2, wherein one or both of the rollers arranged to face each other is positively rotated. 4. The method for producing a long fiber-reinforced synthetic resin strand according to claim 2, wherein both of the rollers arranged to face each other are positively rotated in the same direction or in the opposite direction. 5. The method for producing a long fiber reinforced synthetic resin strand according to claim 1, wherein the roller is eccentrically arranged so that the long fibers meander along the traveling direction. 6. The method for producing a long fiber reinforced synthetic resin strand according to claim 1, wherein the long fibers drawn out from the synthetic resin bath container are taken in a twisted state.