JPS61125813A - Manufacture of resin pellet including metallic fiber and device thereof - Google Patents

Abstract

PURPOSE:To produce pellet easily at low cost, while preventing the breakage of fiber by shearing a metallic sheet into a plurality of small guage wires, applying shearing force on both surfaces thereof, after a plurality of continuous longitudinal stripe grooves have been formed on both surfaces of said metallic sheet. CONSTITUTION:The metallic sheet 1 paid out continuously from the coil of metallic sheet is guided by guide rolls 3, and simultaneously a plurality of stripe grooves 2a, 2b.... Are formed on both sides of the sheet by stripe groove forming rolls 5A, 5B opposite to said both sides. The sheet 2A in which the stripe grooves 2a are formed, is shown into small guage wires by a pair of upper and lower shear forming rolls 8A, 8B in between tension rolls 4, 7. The bundled wires 2C bundled by guide rolls 9 is caused to pass through the tow like wire passing path of a composite making device 12. Then, molten resin 13 is supplied to the bundled wires 2C at the intermediate part of the composite making device 12, and the gaps among the bundled wires 2C are impregnated with said resin. The composite wire 2D discharged from a nozzle 12C is forcibly cooled by blown cooling air 16, etc. And the resin is cured. Said composite wire 2D is cut into pellets by the cutter 22 with rotation edges 21.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is directed to a method in which metal fibers are wrapped in a synthetic resin in an impregnated state.
The present invention relates to a method for producing pellets and an apparatus therefor.

As metal fibers, for example, pellets obtained by mixing conductive metal fibers and resin in a resin are molded using, for example, an injection molding machine.

[Prior Art] (Background) Devices that generate high frequencies (10 to 1000 MHz generated in the air) such as digital devices are not regulated by the FCC. Generally, electric cables using digital ICs)
Many devices malfunction when exposed to high frequencies. If the case of the device is made of steel, it has a shielding effect against high frequencies, but cases are increasingly being made of plastic to reduce weight. However, since plastic and casing have almost no electromagnetic shielding effect, one method to improve this problem is to coat the plastic plate with a paint that has an electromagnetic shielding effect, but this requires a coating process and the coating film is It is not practical because it may cause peeling. Therefore, conductive composite plastics in which a conductive material is mixed into plastic have been developed. The conductive material may be in the form of conductive metal powder, flakes, or fibers, but metal fibers are preferable because a shielding effect can be obtained with a small amount of the mixed material.

(Conventional method).

The conventional method for obtaining conductive resin pellets mixed with metal fibers is as follows:
As shown in FIG. 16, resin pellets 101A and conductive metal fibers 1OIB are mixed in a mixer 102 to achieve uniform dispersion, and then a mixture 103 is introduced from a hopper 105 of an extruder 104 and heated 106. While doing this, the mixture is melted and kneaded using the screw 107 and extruded from the small diameter nozzle 108.

Along with this extrusion, the composite resin is cooled in a linear shape 109 to be cured, and finally cut into short lengths by a cutting machine 110 to obtain composite pellets.

Another method is to first melt and knead only the resin, then add the fibers and further cross-mix them to uniformly disperse them, and then pelletize them in the same manner as above.

When obtaining a molded product from the composite pellets obtained in this way, extrusion molding and l'''''iiu・8&
<t-' y) tFGI1mm&Ht,・″゛1
Injection molding involves extruding the material from a diameter nozzle into a mold.

[Problem that the invention seeks to solve]

As mentioned above, in the conventional method, processes such as mixing, crosstalk, and outflow from a narrow nozzle are performed repeatedly.In the mixing process, cylindrical resin pellets with dimensions of 2 to 5 wt in diameter and 2 to 5 m in length are Nominal diameter 20~60μ x length 1~4
Since the 111 metal fibers are mixed into n1 pellets and the positions of the fibers are constantly exchanged, the fibers are repeatedly subjected to large plastic deformations.

In addition, in the crosstalk process, the resin becomes a highly viscous fluid (laminar flow), and in the outflow process from the three elements of shearing, flow separation, and position exchange, it becomes a contraction flow when flowing out, so the shear of the resin The fibers are subjected to repeated tension and bending due to the entanglement of fibers, friction with the nozzle wall, etc.

Entanglement of fibers also occurs during mixing and kneading. When tensile stress is applied in the entangled state, or when tensile stress is applied due to bending and kinking,
Fibers break (break) even under particularly low stress. The breakage shown above is due to low cycle fatigue in all cases.

By the way, when designing a conductive plastic that has the desired conductivity and shielding effect, the smaller the amount of fibers mixed in, the more weight and cost can be achieved without impairing the properties of the resin.

In this respect, it is preferable to use metal fibers as the fibers because, as mentioned above, the amount of metal fibers used can be small. Why is the amount of contamination reduced when using metal fibers? One reason is that, compared to other fillers, there are more opportunities for fibers to come into contact with each other for the same amount of filler, and moreover, it has better conductivity than those with a larger proportion of fibers per unit length. .

Therefore, as for metal fibers, the smaller the nominal diameter d perpendicular to the longitudinal direction of the fibers and the larger the aspect ratio indicated by the ratio L/d of the fiber length to d, the higher the volume mixing rate (vo
l%) may be small.

In this way, the method of using metal fibers as fibers and making full use of the significance of their inclusion is to ensure that the metal fibers do not break during mixing, cross-wiring, or molding, and are evenly mixed in the molded product as the original fibers. However, as mentioned above, in the conventional method, the metal fibers are broken due to causes originating from the manufacturing process, and sufficient performance cannot be obtained.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a method and apparatus for manufacturing resin pellets mixed with metal fibers, which have almost no breakage of metal fibers and are easy to manufacture. Means] The method of the present invention for solving the above-mentioned problems is to divide a long thin metal plate into many parts in the width direction, and to create many metal wires! A thinning process for obtaining I, a focusing process for converging the thin metal wires, a composite process for impregnating the fine wire bundle with molten resin to form a state in which many fine metal wires are aligned in the resin, and a composite wire. This method is characterized by comprising a step of cutting the pellets in the longitudinal direction into short composite pellets.

In addition, the manufacturing apparatus of the present invention has the following features: (a) A large number of grooves that are spaced apart in the width direction on both surfaces of a thin metal sheet that is continuously passed through, the width direction positions of which are the same on both surfaces, and which are continuous in the longitudinal direction. (b) shearing means that applies shearing force to both surfaces of the thin plate on which the grooves are formed and shears each groove as a cutting line to obtain a large number of fine metal wires; (c) (e) an impregnating means for supplying molten resin to the tow-like passageway through which the bundled wire passes; and (e) wrapping the bundled wire in an impregnated state with resin. Means for cooling the composite wire, (to) cooling hardening n
A cutting means for cutting the t'c compound composite short wire is sequentially arranged in tandem.

The main points of the present invention are as follows: 0. It is possible to obtain metal fibers that are difficult to break.
01 [Function] According to the present invention, first, a long thin metal plate is divided into many pieces in the middle direction to obtain thin metal wires. As shown in FIG. With respect to each groove opening divided by each groove by the shearing roll, - for the surface, one groove opening is pressed, and for other surfaces, one groove opening that is different from the other surface is pressed. A large number of metal wires are obtained by applying a shearing force along each groove as a boundary by pressing the opening, and shearing each groove using the groove as a cutting line.

According to such a wire thinning process, an unreasonable force is not applied during wire thinning, there is no work hardening on the cut surface, there is no occurrence of burrs, and it is possible to obtain a thin metal wire that has high strength and is difficult to break.

The metal wires are concentrated in large numbers and prepared for resin impregnation in a subsequent coalescence step.

The focused NFC, 1lIl wire bundle is passed through a tow-like passageway, during which molten resin is supplied, and the thin wire bundle is impregnated with molten resin.0 The molten resin penetrates between each thin wire. At the same time, the thin wire bundle exits the tow-like passageway with the molten resin surrounding it as a whole.

Before or after exiting this tow-like passageway, the molten resin in a softened state is cooled down, and the resin is hardened. As a result, a composite wire in which a large number of metal fibers are aligned in the longitudinal direction in the resin is obtained.The composite wire is then cut into short lengths and made into pellets.In such a manufacturing method and apparatus, There is no mixing or cross-talk required in conventional methods. Therefore, there is almost no tearing or damage to the metal fibers, the mixed metal fibers exhibit their original function, and excellent quality is obtained.

On the other hand, there is a method for manufacturing metal fibers called Tiller.
r) method, melt extraction (Melt Ex
traction) law, focused traction! There are methods such as punching tkm, chatter cutting, thin plate cutting, etc., but many of the fibers produced by these methods break during mixing and cross-fertilization, making it impossible to obtain the desired performance. The reason why such metal fibers are easy to break is that Al flakes and l
This is because the fibers have low tensile strength and are torn apart by shearing of the resin during compaction or cross-wiring. In addition, fibers made of AJ, brass, mild steel, etc. produced by the vibration vibration cutting method have a cutting surface on the entire surface of the fibers, are extremely work hardened, and have fine notches on the entire surface due to cutting, making them susceptible to notches. Extremely expensive. Therefore, the tensile strength and low cycle fatigue strength are low, and it is easy to break. Even in the thin plate cutting method, the strength of the rolled surface is high, but some cracks occur on the sheared surface and some of its corners, which become notches and reduce the strength.

The metal fiber according to the present invention once forms grooves, and
Since it is sheared as a cutting line, breakage is unlikely to occur. [Specific Examples of the Invention] The present invention will be explained in more detail below with reference to the drawings. Figures 1A and 1B are basic diagrams, and Figures 2 and after These are concrete example diagrams of each process.

1 is a metal thin plate coil, from which a metal thin plate 2 is continuously drawn out. The rolled-out metal thin plate 2 is guided by a guide roll 3 and is placed under tension by a tension roll 4, facing both surfaces.
Grooving roll 5A.

5B, a large number of grooves 2a+ 2a... are formed on both surfaces.
As shown in FIG. 2, the zero groove processing rolls 5A, 5B on which the grooves are formed have a large number of V-shaped wedge-shaped teeth 5a continuous in the circumferential direction at equal intervals in the width direction. As shown in FIG. 3, the O4 rolls 5A and 5B whose teeth 5a are at the same position in the width direction are strongly pressed against the thin plate 2, and as a result, the fourth As shown in the figure, the thin plate 2 has V-shaped grooves 2 a + continuous in the longitudinal direction on both surfaces thereof.
2 a + .
0 g (m) is preferred. Also, the gap CI between the opposing tips of the teeth 5a, 5a is 0.3 to 0.3 based on the thickness t of the thin plate 2゛.
0.8t is desirable. In addition, the thickness t of the thin plate 2 is 7μ to 1
00μ is preferred.

In order to improve groove workability and uniform wear on the tooth surface, roll teeth are preferable as shown in the example above.
As shown in the figure, a large number of knife-like cutters 6 are arranged in parallel, or as shown in Fig. 7, they are arranged in a staggered manner to form a 0-strip groove 2a, which may be processed by cutting into the grooves 2a. 2 people are tension roll 4. While tensilan is applied between the sheets, the wire is sheared into thin wires by a pair of upper and lower shearing rolls 8A and 8B. The rolls 8A and 8B have trapezoidal teeth 8a that are continuous in the circumferential direction and have a flat bottom surface, and have a positional relationship in which the peaks of the teeth of one roll face the troughs of the other roll. Tosaniteru 0 pitch P2
is the same as pitch P1, n1 gap C2 is t C1, height h of zero tooth 8a is t to 1.2t in h, and actual image width E is 0.6t to 0.9t.

The inside of the bottom surface is 0.6t to 1.0t in 1m. Ot is desirable. Such rolls 8A, 8B are strongly suppressed against the two sheet metal members. At that time, when the teeth of one roll are in contact with one of the next areas divided by the grooves 2a, the teeth of the other roll are in a positional relationship with the adjacent area. Therefore, when two thin plates are strongly pressed through each tooth 8a,
Upper and lower corresponding grooves 2 are provided between the two regions and the adjacent region.
a.

A shearing force is applied to the groove 2a, and the shearing force is applied to the groove 2a.
, 2a concentrates on the boundary part, groove 2a + 2a
It is sheared and divided using the cutting line as the cutting line. As a result, a large number of thin metal wires 2B, 2B, . . . are obtained.

By the way, as can be inferred from the above explanation, V
The main reasons for forming the grooves 2a are, firstly, to ensure accurate shearing at the grooves 2a, secondly to enable shearing with low shearing force, and thirdly to ensure smooth shearing. The purpose is to improve the mechanical properties of the fiber by obtaining a shear plane 2b. Regarding the third point, the chatter vibration cutting method,
When using the thin plate cutting method or when fibers are simply slit using rectangular cross-section teeth, some corners are generated and the corners are
However, if the grooves are formed in advance according to the method of the present invention and then sheared, especially if the 7-shaped grooves are formed, the corners will be rounded. Since there is no n1 burr, the shape is similar to that of a die-drawn wire having a circular cross section, and the mechanical properties are improved.

The reason why the shearing tooth 8a'ft cross section is trapezoidal as in the above example is because, for example, in the rectangular tooth 8'a as shown in FIG. This is because the film will dig into the film, making it difficult to peel it off. For this,
Trapezoidal or substantially trapezoidal teeth provide an escape space for deformation of the fibers during shearing, thereby preventing biting.

Shearing teeth can be formed on the outer periphery of the roll as in the example above, or formed on one end surface of a flat plate.
A method of stacking knives with a pitch of P2 thickness, a method of stacking knives having teeth on the outer periphery, and a method of stacking disks with a pitch of P2 thickness to form a roll shape can be adopted. This last method is also applicable to V-grooving rolls.

Although the above example is an example of a single metal thin plate, if necessary, a laminated thin plate of a plurality of plates can be used as the original plate and subjected to groove processing and shearing processing.

Now, the sheared thin metal wires 2B, 2B, . . . are sorted and bundled in order to mix a predetermined number of wires into the final pellet. In this case, although it is schematically shown as a guide roll 9 in FIGS. 1A and 18, specifically as shown in FIG.
Many guide rolls 9A.

9B and 9C, and after sorting using a knife 101, convergence is performed by a converging roll 11. That is, the strip-shaped thin metal wire 2 coming out from the tension roll 7
Group B is sorted by 10 groups of friend knives, which are sorted by a predetermined number while the width is regulated by guide rolls 9A, 9A, and then collected as a group line by guide rolls 9B, 9C and arranged in a row.Finally, The focusing roll 11 focuses the wires into a focusing wire (fine wire bundle) 2C having a circular cross section. Here, the guide rolls 9A to 9C also serve as focusing means.
It functions as follows.

In this step, if necessary, surface treatment (degreasing, coating, plating, etc.), heat treatment, etc. are performed. Also,
At this stage, each of the focused wires 2C may be wound into a coil and composited at another location. Furthermore, if the number of wires is small, the tension roll 5
After exiting, the focusing process is immediately started.Next, each focused line 2C is composited, then cut and pelletized, but FIGS. 1A and 18 show the processing process for only one focused line. Now, the condensing wire 2C is passed through the tow-like passageway 12a of the composite device 12. At this time, it is connected to the tow-like passageway 12a and the molten resin supply passage 1
Molten resin 13 is supplied from 2b. The composite device 12 is heated 14' by a heater 14, etc., and melts the molten resin 13 at the middle part of the passageway tZa with respect to the bundled wire 2C that enters the passageway 12a from a guide hole slightly larger than the toe diameter. When the molten resin 13 is supplied, the molten resin 13 impregnates the gap in the focusing line 2C and wraps around it. If the impregnating property is suitable, heating is unnecessary.The composite ratio of O fibers is determined by the cross-sectional area of the nozzle outlet. In other words, prepare several nozzles with different exit diameters such that the volume ratio is the cross-sectional area of one metal fiber (am) x the number of focused fibers (n) = Am and the nozzle exit cross-sectional area A, and The fiber mixing rate can be changed by replacing. Further, the mixing rate can also be changed by increasing or decreasing the number of bundled fibers. Furthermore, by changing the shape of the nozzle outlet, pellets' having various cross-sectional shapes can be obtained.

The composite line 2D exiting from the nozzle 12c is connected to the guide roll 15.
At the same time, the resin is forcibly cooled by blowing 16 tons of cold air, etc., and the resin is cured. At the end of the process, it is pulled by one or more pairs of tension rolls 17 and sent to the subsequent cutting process.

Thereafter, the hardened composite wire 2D is sent between the fixed blade 19 and the guide 20 by the guide roll 18. The wire diameter (of the composite wire) plus 0.05
They are arranged with a gap of about 0.2 mm and have a flat plate shape. At the outlet, a cutting machine 22 is provided which has a plurality of rotary blades 21 arranged radially at equal intervals around the outer circumference of a rotary disk. An example of the shape of the pellet 2E is shown in FIG. 15, which is preferably determined by changing the rotation speed of the blade 21. The pellet length l is 1.0 to 5.0 mm, and the diameter φ is 1.0 to 5 The obtained FT7'C composite pellets are mixed with about 100 to 2,200 metal fibers fi. 〇〇〇〇〇〇〇〇〇〇〇〇〇〇〇〇〇〇A brass foil with a thickness of 50 μm and a mild steel foil with a thickness of 30 μm were used as metal thin plates to form resin pellets mixed with metal fibers using the same method and equipment as in the above specific example. First, coiled brass (6-4 brass plate) thin strip plate (50 μt x 21.5 m width)
The zero-groove processing roll, which is unwound from the coil and bitten into the groove processing rolls 5A and 5B through a guide roll and a guide guide (arranged on both sides, not shown) 3, has a diameter of 50ioaφ and an outer periphery. To the depth of approximately 3WIL, cemented carbide is molded, and teeth with a wedge-shaped cross section are formed on the outer periphery of the tooth. The grooved rolls 5A, 5B and the tension roll 4.4 with urethane rubber pasted on the outer periphery are driven by a separate roll drive device with a depth of 50 μm and a rounded radius of the tooth tips of approximately 1.5 μm. V-shaped grooves are provided on the front and back sides of the thin plate 1. At this time, the groove processing roll 5A.

Gap C1t between 5B - 0.3t to 0.8 of metal thin plate thickness t
You can process it without any problem even if you change it arbitrarily between t. Since the mill rigidity coefficient was set to 5001w/μm, the roll tooth profile was slightly widened due to the gap expansion and spring spring.1 dimension is a slightly rough groove dimension, and 2fc was the number of 0 grooves without any problem. In addition, a thin metal plate with KV-shaped grooves on the front and back sides was sheared at the bottom of the groove.
Shearing rolls 8A and 8B are used for shearing, and the outer periphery of the shearing rolls 8A and 8B is a groove processing roll 5.
Similar to A and 5B, the teeth are made of cemented carbide and have a trapezoidal cross section.The pitch P2 of the fCo teeth is 50μ, and the other dimensions are! 〒
=30μ, 1B=30μ, and h=60μ. Roll 8A for zero-shear processing has an outer diameter of the tooth convex portion of 50 m.

8B was installed in a roll stand and driven, and at the same time, a tension rolla with urethane rubber attached to the surface was driven, and 7 was pulled and sheared to obtain a large number of metal fibers. At this time, a shearing roll was used. Gap C between 8A and 8B
A large number of parallel brass wires, which could be sheared at t-Cs, were divided by a wooden metal knife 10. The two knives at both ends were provided to remove two or three wires with defective dimensions due to meandering during feeding of the metal fibers. A large number of urethane resin rolls were arranged to perform guiding and focusing, and the brass wire was collected into a tow shape.

The composite device was made of tempered steel, and the inner wall of the hole was finished with chrome plating. The diameter of the fiber bundle guide hole is 1 mm φ, the nozzle exit diameter is 3 mm φ, and the distance from the inlet to the outlet is 50 m. The maximum inner diameter of the 0-through line is 6 mm φ, and the diameter decreases as it approaches the nozzle exit. Make sure to squeeze it. Molten resin is injected from the molten resin injection port, filling the composite chamber of the passageway, and passing through the metal fiber bundle to form a metal fiber-mixed resin wire. The resin used is flame-retardant ABS resin (flow characteristic: 0.5 cc/
Temple, 210℃, 30yu/d).

The metal fiber-containing resin wire composited by the composite machine is forcibly cooled by cold air on the line, and the metal fiber-containing resin is hardened by two pairs of steel tension rolls 17 with 1.5R grooves. Pull the wire and pass it through the guide roll (made of steel) with a fixed blade (made of high speed steel).

Metal mixed on HRC60, 1010X10X40 Here, the torque of the shearing roll and tension roll is transmitted from separately provided rotary power via a powder clutch, and metal is mixed at any position. The thin plate and metal fibers were placed under tension. Therefore, the movement speed at the beginning and end of the entire process is the same. The maximum moving speed was 2.0 rrL/SeC, but it can be further increased by improving each part.

Table 1 shows an example of the metal fiber-containing resin pellets produced through the process described above.

Table 1 In Table 1 1' above, 2. Knead the pellets with a slow 4 injection molding machine and mold them into a 2 amt x 30 mi + x 30 dragon plate. For comparison, a similar plate was produced using a conventional method and using pellets. The results are shown in Table 2.

Table 2 As described above, the molded plate obtained by injection molding of the resin pellets mixed with metal fibers obtained by the method of the present invention has only one crosstalk during injection molding. Compared to molded plates made of resin pellets (in the conventional method, crosstalk occurs twice, once during the production of the resin pellets and once during molding), the metal fiber breakage rate is lower, and the volume resistivity is lower.
The 7-rode effect is also good.

In addition to brass and mild steel, alloy steel, 5US304%
Stainless steel such as 5US430, Zn or Sn
It has become clear that it can be similarly easily manufactured using plated steel plates such as, aluminum plates, etc. as raw materials.

〔Effect of the invention〕

As described above, according to the present invention, fiber breakage can be prevented as much as possible and pellets can be easily produced.

[Brief explanation of the drawing]

FIG. 1A is a schematic front view showing an example of the present invention, FIG. 1B is a plan view thereof, FIG. 2 is a diagram showing the arrangement of upper and lower teeth of the groove processing roll, FIG. 3 is a diagram showing the groove processing state, and FIG. Fig. 4 is a perspective view showing a state in which grooves are processed f'L'fc, Fig. 5 is a schematic front view of another example of groove processing using a knife, and Figs. 6 and 7 are examples of the arrangement thereof. A plan view, FIG. 8 is a diagram of the arrangement of the upper and lower teeth of the shearing roll, FIG. 9 is a diagram of the shearing state, FIG. 10 is a perspective view of the thinning state after shearing, and FIG.
The figure is a shear state diagram due to unsuitable rectangular teeth, Figure 12 is a plan view of the sorting/focusing process, Figure 131 is a schematic front view of the compounding process, Figure 14 is a schematic front view of the cutting process, and Figure 15 is a schematic front view of the compositing process. The shape of the composite pellet is shown, (a) is a plan view, (b)
) is a front view, (C) is an end view, and FIG. 16 is a schematic explanatory diagram of the conventional method. 2a...Groove 5A, 5B...Roll for groove processing 8A
, 8B... Rolls for shearing 9A to 9C... Guide (focusing) roll 10... Knife for sorting 11... Focusing roll 12...
Composite device 12a...Tow-shaped passageway 16...Cold air
19...Fixed blade 21...Rotary blade 22...Cutting machine

Claims (2)

[Claims] (1) A thinning process to obtain a large number of thin metal wires by dividing a long thin metal plate into many pieces in the width direction, a convergence process for converging the thin metal wires, and a process of impregnating the thin wire bundle with molten resin. a compounding process in which a large number of thin metal wires are aligned;
A method for producing resin pellets mixed with metal fibers, comprising the step of cutting a composite wire in the longitudinal direction to obtain short composite pellets. (2) An apparatus for manufacturing metal fiber resin pellets, characterized in that the following means are sequentially arranged in tandem. (b) Groove forming means for forming a large number of grooves that are spaced apart in the width direction on both surfaces of a thin metal sheet that is continuously passed through, the width direction positions are the same on both surfaces, and the grooves are continuous in the longitudinal direction; (b) A shearing means that applies shearing pressure to both surfaces of the thin plate on which the grooves are formed and shears each groove as a cutting line to obtain a large number of thin metal wires; (c) A focusing means that collects a large number of the thin metal wires. , (d)
an impregnating means for supplying molten resin to a tow-like passageway through which the bundled wire is passed; (e) a means for cooling the softened composite wire wrapped in resin while the bundled wire is impregnated; (f) cooling hardening. A cutting means for cutting the composite wire into short lengths.