JPH06254855A - 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 cross the track of the running filaments and contact the filaments in a molten resin container for impregnating the filaments with the resin and conducting the impregnation while the container and/or the rollers or the molten resin itself being vibrated. CONSTITUTION:Either one of opening and impregnating rollers 6a, 6b or both of them which press an impregnation head (molten resin container) 1 and a roving 3a are made to be vibrant, a vibrating plate is placed in the impregnation head 1, ultrasonic waves are applied, or some other methods are employed in order to vibvrate the molten resin itself. In this way, the impregnation of the filaments with the resin can be improved. In order to reduce troubles caused by fluff in the roving 3a, the roving 3a is preferably drawn while a resin impregnated roving 3b being twisted.

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. In addition, it is a gist to impregnate the long fibers with resin while vibrating either or both of the container and the roller or directly vibrating the synthetic resin bath itself.

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, one or both of the impregnation head containing the molten resin and the opening / impregnation roller against which the roving is pressed are vibration type instead of the static type as in the conventional case. Alternatively, a vibrating plate or the like is placed in the impregnation head, or ultrasonic waves are applied to directly vibrate the molten resin itself, so that the molten resin and / or the roller vibrates and the resin impregnability is increased. Is improved. That is, the vibration of the roller promotes the opening of the roving, and the vibration of the molten resin has the effect of increasing the number of collisions with the roving due to its own flow and further promoting the pressure penetration into the roving gap. Therefore, if a configuration is adopted in which both the molten resin and the roller are vibrated, the molten resin is brought into the opening gap at the same time when the roving is opened, and a synergistic effect is exhibited. Moreover, this carry-in acts so as to exert a large resin pressure on the roving because the molten resin has a high viscosity. Therefore, the molten resin is positively pushed into the opening gap, and the impregnation property is improved at once. The opening and impregnating rollers may be arranged in a single row so as to prevent the running locus of the roving from becoming substantially straight, but may be arranged in a zigzag pattern so as to positively meander.

Further, the rollers may be in contact with the traveling roving from only one direction, or may be in contact with each other alternately from both directions. Most preferably, the rollers are lightly pressed from both sides so as to sandwich the traveling roving. It is an array that does. The vibration direction of the opening and impregnating roller is one of the axial direction of the roller, the orthogonal direction (including the vertical direction and the horizontal direction), or the circumferential direction, or a combination thereof. When arranging the rollers so that they come into pressure contact with each other, it is recommended to vibrate in alternating directions in the case of axial vibration, and to vibrate in the directions of orthogonal vibration. It Such direction control can be performed when vibration is applied by mechanical means, and in addition, when vibration is applied by using ultrasonic waves, when the molten resin has thixotropic properties, it contributes to a decrease in resin viscosity. The impregnating property can be further enhanced.

Next, 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 of preventing fluffing from occurring and devising the fluff to be 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 outlet nozzle is prevented, and even if continuous operation is performed for a long time, the trouble of taking out the resin-impregnated long fibers does not occur and excellent productivity can be exhibited.

[0015]

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, the impregnation head 1 is filled with the molten synthetic resin that is pressed in from the molten synthetic resin pressure inlet 2 in the direction of the arrow M. The impregnating head 1 and / or the rollers 6a and 6b are vibrated by a vibrating mechanism (not shown), or the resin itself is vibrating by a vibrating plate (not shown), so that the roving 3a passes through the rollers. The resin is impregnated upon receiving the reliable fiber opening, and is taken out from the outlet nozzle 5 in the direction of arrow B as the resin impregnated roving 3b. 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, other than the flat roller type shown in the figure, a drum type roller type having a large diameter in the central portion in the axial direction may be used.

FIG. 3 shows the facing arrangement type described above. The type used here is preferably the flat roller type, and the presence or absence of the groove can be freely selected. In any case, by applying the vibration as described above, a sufficiently satisfactory degree of impregnation can be 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.

[0018]

EFFECTS OF THE INVENTION Since the present invention is constructed as described above, the opening of rovings is promoted, or the number of collisions of resin and roving is increased, and the resin impregnation property becomes very good. . 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

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Reference number within the agency FI technical display location // B29K 105: 08 (72) Inventor Koichi Hashimoto 1-5-5 Takatsukadai, Nishi-ku, Kobe-shi, Hyogo Issue Kobe Steel Works, Ltd. Kobe Research Institute (72) Inventor Takehiko Ashinaga 1-5-5 Takatsukadai, Nishi-ku, Kobe-shi, Hyogo Kobe Steel Works Kobe Research Institute

Claims (2)

[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 any one of the container and the rollers. A method for producing a long fiber-reinforced synthetic resin strand, which comprises impregnating the long fibers with a resin while vibrating one or both of them or directly vibrating the synthetic resin bath itself. 2. 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.