JPH06254856A - Manufacture of filament reinforced synthetic resin strand - Google Patents

Abstract

PURPOSE:To impregnate filaments with a molten resin as completely as possible by installing alternately die members which squeeze and pass the filaments and opening and impregnating rollers in a molten resin container for impregnating the filaments with the resin. CONSTITUTION:Die members 11 which squeeze and pass the filaments and opening and impregnation rollers 6 are installed alternately along the track of the running roving 3a in an impregnation head (molten resin container) 1. The die members 11 accelerate the impregnation by squeezing the molten resin existing in the space in the bundle of the roving 3a, while the opening and impregnating rollers 6 open the roving 3a to help the molten resin enter the openings among the filaments. The squeezing and opening are repeated. Rollers such as flat rollers, rollers with channels attached with partitioning projections, drum type rollers can be used as the opening and impregnating rollers. In order to reduce troubles caused by fluff in the roving 3a, the roving 3a is preferably drawn with a resin impregnated roving 3b 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 impregnate the long fibers with the molten synthetic resin more than sufficiently. In the conventional technique, the fibers are opened in the impregnation head.
It has been performed that a plurality of rows of impregnating rollers are provided and a bundle of traveling rovings is brought into contact with the rollers so as to be pressed to open the fibers to enhance impregnating property. 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]

Means for Solving the Problems The method of the present invention which has been able to achieve the above-mentioned object is a die member for squeezing and passing long fibers into a synthetic resin bath container, and a resin is obtained by opening the long fibers. The gist of the present invention is to impregnate the long fibers with a resin by alternately providing opening and impregnating rollers for promoting impregnation.

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]

[Function] Conventionally, the focus of the research has been to devise the arrangement and shape of the fiber opening / impregnation roller, but in the present invention, the die member and the fiber opening / impregnation roller for narrowing and passing the roving are It adopts a configuration in which it is arranged alternately along the locus of roving. Therefore, the molten resin intervening in the bundle space of the roving is moved within the bundle space by squeezing with a die member, and the impregnation is promoted by the action of pressing it against the surface of each unit fiber, while the squeezed roving is removed. The fibers are spread widely across the roller surface by the fiber opening / impregnation roller to open the roving, and the molten resin is infiltrated into the fiber gap to impregnate and prepare for the next squeezing by the die member. The main point of the present invention is to repeat the above-described narrowing down and development, and the die member and the fiber opening / impregnation roller itself can be freely designed and selected as long as they exhibit the above-mentioned basic actions. For example, the die member may be provided with an operating mechanism such as turning, and the opening / impregnation roller may be changed in shape such as a flat roller, a grooved roller, or a drum-shaped roller, or It is possible to add an operating mechanism such as vibration and positive rotation, and further add a mechanism for decreasing the viscosity such as heating.

The opening and impregnating rollers may be arranged in a single row so as not to prevent the running locus of the roving from becoming substantially linear, but may be in a zigzag arrangement 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. Will be much less.

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, the roving can be opened with a relatively light pressing force by adjusting the gap between the facing rollers. 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, the trouble of taking out the resin-impregnated long fibers does not occur and excellent productivity can be exhibited.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an explanatory view showing the basic constituent parts of the present invention. In the figure, from the top, a flat roller type opening / impregnating roller 6, a squeezing die member 11, the same roller 6, and the same die member are shown. 11, drum-type roller type opening and impregnating rollers 12 are arranged, and the roving 3 is running from the upper side to the lower side. Opening and impregnating rollers 6,1
All of 2 may be flat roller type or all may be drum type roller type, and the selection arrangement thereof is completely free. For convenience of understanding, the partitioning projections 9 provided on the rollers 6 and 12 in FIG.
Therefore, the number of grooves on the rollers 6 and 12 is four, but in order to make the expansion (lateral expansion) effect more conspicuous after narrowing down, the full length of the rollers 6 and 12 is used. It is recommended to provide a large number of partitioning projections 9 over the entire length.

As can be seen from FIG. 1, the traveling distance of the roving 3 traveling on both ends of the roller 6 is longer than that of the roving 3 traveling on the central portion of the roller 6. However, since the roving 3 travels by pulling, there is no inconvenience in impregnation operation. However, when the drum-shaped roller 12 is passed through, the difference in running distance between the both ends (small diameter) and the center (large diameter) is reduced, so that the above problems are greatly reduced.

FIG. 2 is a side view explanatory view conceptually showing an apparatus for carrying out the present invention, and FIG. 3 is a plan view explanatory view. In these figures, 1 is an impregnation head (synthetic resin bath container),
Reference numeral 2 denotes a molten synthetic resin pressure inlet, the roving 3a sent from the arrow A enters the impregnation head 1 from the inlet nozzle 4, and the roving 3a alternately passes through the opening / impregnation roller 6 and the die member 11. After that, it is taken toward the outlet nozzle 5 through the guide roller 7 and the converging roller 8 in which these rollers are arranged orthogonally. On the other hand, since the impregnation head 1 is filled with the molten synthetic resin pressed in from the molten synthetic resin pressure inlet 2 in the direction of the arrow M, the roving 3a is impregnated with the resin while passing through the front rollers 6 and the die member 11. Then, the resin impregnated roving 3b is taken out from the outlet nozzle 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 a result of the good impregnating property obtained by the above-mentioned constitution, the fluffiness of the fiber is reduced, the feedability in the process of manufacturing an injection-molded article using the fiber is improved, and the measuring time in the injection molding machine is improved. Because it's short and stable,
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 troubles due to fluff, the following constitution 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 can be generated by the rubbing of the die member 11 and the outlet nozzle 5 is in the generation / growth process. The exit nozzle 5 gets caught in the twist
Along with the resin-impregnated roving 3b that is drawn from the fiber, it 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.

[0021]

Since the present invention is constructed as described above, the resin impregnation property is 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 an explanatory view showing an implementation concept of the present invention.

FIG. 2 is a side view explanatory diagram showing an apparatus for carrying out the present invention.

FIG. 3 is an explanatory plan view showing an apparatus for carrying out the present invention.

[Explanation of symbols]

 1 Impregnation Head (Synthetic Resin Bath Container) 2 Melt Synthetic Resin Pressure Inlet 3a Roving 3b Resin Impregnation Roving 4 Inlet Nozzle 5 Outlet Nozzle 6 Fiber Opening / Impregnation Roller 7 Guide Roller 8 Converging Roller 11 Die Member 12 Drum Type Fiber Opening Impregnation roller

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Claims (4)

[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 a method for producing a long fiber-reinforced synthetic resin strand, a die member for squeezing and passing the long fibers into the synthetic resin bath container, and opening / impregnation for promoting resin impregnation by opening the long fibers A method for producing a long fiber-reinforced synthetic resin strand, characterized in that the long fibers are impregnated with resin by alternately providing rollers for use. 2. The method for producing a long fiber reinforced synthetic resin strand according to claim 1, wherein the opening / impregnation roller is provided with a partitioning projection provided in a circumferential direction thereof. 3. The method for producing a long fiber-reinforced synthetic resin strand according to claim 1, wherein the fiber opening / impregnation roller is a drum-shaped roller having a large diameter in the central portion in the axial direction. 4. 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.