JPH06262624A - Manufacture of long carbon fiber reinforced synthetic resin strand - Google Patents

Abstract

PURPOSE:To improve electromagnetic and magnetic shielding properties of a molding by a method wherein metal plating is applied to the surface of long carbon fibers running under opening state and then the fibers are introduced in a synthetic resin bath so as to be impregnated with resin. CONSTITUTION:Long carbon fiber rovings 1a and 1b are paralleled and continuously fed to a plating tank 2 so as to run roving bundle 1 under the opening state being immersed in plating liquid 3 in order to plate the surface of the respective long carbon fiber rovings 1a and 1b with metal. Next, the roving bundle 1 is introduced in a drying device 4 so as to remove the electrolyte on the surface of the roving bundle 1 by drying. In succession, the resultant roving bundle 1 is lead in a synthetic resin impregnating device 5 so as to infiltrate molten synthetic resin supplied from a synthetic resin supplying device 5a in the roving bundle 1 running in the impregnating device 5 under opening state. Next, after being post-treated (or solidified by cooling in the case of thermoplastic resin and treated by heating in the case of thermosetting resin) in a post-treating device 6, the roving bundle 1 after being simpregnated with resin is wound up through take-off rolls 7 to a winding-up device 8 in the form of long carbon fiber strand.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing long carbon fiber reinforced synthetic resin strands, and in particular, to the surface of long carbon fibers used as reinforcing fibers for fiber reinforced resin, which is subjected to metal plating, thereby providing a radio wave shielding property. The present invention relates to a method for producing a long carbon fiber reinforced synthetic resin strand capable of obtaining a fiber reinforced resin molded product having characteristics such as magnetic shielding properties and magnetic properties with high productivity.

The strand-shaped material produced by the method of the present invention can be used as it is, or can 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 a carbon long fiber reinforced synthetic resin strand (hereinafter may be simply referred to as carbon long fiber strand), and the latter is a carbon long fiber reinforced synthetic resin pellet (hereinafter may be simply referred to as carbon long fiber pellet). Classify as.

[0003]

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 materials are generally short fibers, but in recent years, long fibers have been aligned in one direction and impregnated with synthetic resin, that is, long fiber pellets have been developed and have high strength injection. It is evaluated as a raw material for manufacturing 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 bundle 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.

On the other hand, the long fiber reinforced resin as described above is widely used as a molding material for casing materials and structural materials of various equipment such as OA equipment and AV equipment. Among them, carbon is used as the reinforced fiber among them. Those using long fibers are
It is known to give excellent properties also in mechanical properties and conductive properties. However, injection molding and compression molding using long carbon fiber reinforced resin cannot provide the radio wave shielding property and magnetic shielding property often required for OA equipment and AV equipment.

Therefore, there has been proposed a method of providing a magnetic shielding property by using metal fibers together with carbon long fibers or by mixing magnetic powder such as metal or metal flakes in an impregnating resin. In this method, there is a problem that the mechanical properties of the molded product deteriorate, or the dispersion of the metal powder becomes non-uniform, so that stable radio wave shielding properties and magnetic shielding properties cannot be exhibited, and OA equipment with ever-increasing performance. It lacks suitability as a constituent material for AV equipment and the like.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and its purpose is to secure the excellent reinforcing effect and conductivity improving effect of carbon long fiber reinforced synthetic resin. At the same time, it is an object of the present invention to provide a method capable of producing a carbon long fiber strand with good productivity, which enables to obtain a molded product having excellent properties in terms of radio wave shielding property and magnetic shielding property.

[0008]

The structure of the manufacturing method according to the present invention which has been able to solve the above-mentioned problems is that the long carbon fibers are aligned and introduced into a synthetic resin bath container, and the long carbon fibers are subjected to the synthesis. In a method for producing a carbon long fiber-reinforced synthetic resin strand by collecting resin-impregnated carbon long fibers from an outlet nozzle of the synthetic resin bath container while impregnating a resin, metal plating is performed while the carbon long fibers are opened and running. Is carried out and then introduced into the synthetic resin bath container for resin impregnation.

Various kinds of metal plating materials can be used. Among them, N is particularly preferable for obtaining a molded product excellent in radio wave shielding property and magnetic shielding effect.
In the case of i, the surface of the nickel plating was oxidized and then introduced into the synthetic resin bath container for resin impregnation, the synthetic resin formed by the oxide film formed on the surface of the plating layer. And a molded product having excellent magnetic shielding properties. Further, in carrying out this manufacturing method, if a method is adopted in which the carbon long fibers drawn out from the synthetic resin bath container are twisted and taken up, the drawing of the carbon long fiber strands impregnated with the synthetic resin is smoothly carried out. This is preferable because it can be performed.

[0010]

As described above, in the present invention, the long carbon fibers are aligned and introduced into the synthetic resin bath container, and the long carbon fibers are impregnated with the synthetic resin while the resin impregnation is performed from the outlet nozzle of the synthetic resin bath container. When producing carbon long fiber reinforced synthetic resin strands by taking up carbon long fibers, the surface of the carbon long fibers before resin impregnation is subjected to metal plating in the production line, thereby providing excellent productivity. Below, it is possible to obtain a carbon long fiber strand which gives a molded article having excellent properties in all of mechanical properties, conductive properties, radio wave shielding properties and magnetic shielding properties.

Hereinafter, the structure, operation and effect of the present invention will be described in detail with reference to the drawings showing the embodiments. Figure 1
It is a schematic explanatory drawing which shows the Example of this invention, 1a, 1 in the figure
b, ... are long carbon fiber rovings, 1 is a roving bundle,
2 is a metal plating tank, 3 is a plating solution, 4 is a drying device, 5 is a synthetic resin impregnation device, 5a is a synthetic resin supply device, 6 is a post-treatment device, 7 is a take-up roller, and 8 is a winding device. ing.

As shown in the figure, in the present invention, the carbon long fiber rovings 1a, 1b, ...
Are continuously fed to the plating tank 2 and the carbon long fiber roving bundle 1 is dipped and run in the plating solution 3 in an opened state, so that the carbon long fiber rovings 1a, 1b,
Metal plating is applied to the surface of. In this metal plating process, an electrolytic solution containing a metal such as Ni is used, and the carbon long fiber rovings 1a, 1b ,.・ ・
The metal is deposited on the surface of.

The type of plating metal is not particularly limited, and N
There are various metals such as i, Fe, and Cr, and accordingly, soluble metal compounds containing such metals (chloride, sulfate, acetate, hydroxide, carbonate, etc.) are used as a plating solution. Ni plating is the most preferable in terms of the plating efficiency and the effect of improving the radio wave shielding property and the magnetic shielding property by the plating treatment. Therefore, the most preferable plating solution is Ni such as Ni chloride, sulfate or acetate. It is an aqueous salt solution.

The roving bundle 1 that has undergone the plating process is then introduced into the drying device 4 and dried. This drying device 4
Then, the electrolytic solution adhering to the surface of the roving bundle 2 is dried and removed. However, if this drying is performed in an oxidizing atmosphere, the surface of the plated metal is oxidized and the affinity with the synthetic resin is formed due to the formation of the oxide film. Is improved and the adhesion between the impregnated resin and the carbon long fiber roving is improved, and the performance as a composite material is further enhanced, which is preferable.

After drying, the synthetic resin is continuously guided to the synthetic resin impregnating device 5, and the synthetic resin supplied from the synthetic resin supplying device 5a in this portion runs in the impregnating device 5 in the opened state. The roving bundle 2 is impregnated in a molten state. Then, after post-processing in the post-processing device 6 (cooling and solidification when a thermoplastic resin is used as the synthetic resin, heat treatment for pre-curing when a thermosetting resin is used), the carbon is passed through the take-up roller 7. The long fiber strands are sequentially wound on the winding device 8.

As described above, according to the present invention, metal plating is performed in the middle of a series of steps from alignment of carbon long fiber rovings to impregnation of synthetic resin and winding. By simply adding plating equipment, the metal-plated carbon long fiber strand of the present invention can be obtained with almost no adverse effects on productivity and the like.

Moreover, the strand thus obtained is
As described above, the surface of the carbon long fiber used as the reinforcing fiber is metal-plated, and thereby, in addition to the reinforcing effect and the conductive property originally possessed by the carbon long fiber,
The metal plating also provides the radio wave shielding property and the magnetic shielding property, and can be effectively used as a casing material for various devices such as OA equipment and AV equipment which require the radio wave shielding property and the magnetic shielding performance. Is possible.

There is no limitation on the diameter or the number of filaments of the carbon long fibers used in the present invention, and it may be adjusted arbitrarily according to the required characteristics of the intended molded article, but it is the most common as a composite material for molding. This is a method of aligning and using a plurality of rovings composed of 3000 to 96000 carbon long fibers having a fiber diameter of 6 to 20 μm. In addition, the amount of metal plating coating is not particularly limited, but if the amount of plating is insufficient, satisfactory radio wave shielding properties and magnetic shielding effects will not be obtained, while if the amount of plating is too large, carbon long fibers will be reinforced. Since the properties of the composite molding material used as a material, particularly elasticity and lightness, may be impaired, the amount of metal plating deposited is 10 to 100 parts by weight, and more preferably 20 to 100 parts by weight with respect to 100 parts by weight of carbon long fiber roving. It is preferable to set it in the range of 50 parts by weight.

There is no particular limitation on the type of synthetic resin used for impregnation, and for example, epoxy, unsaturated polyester,
Thermosetting resin such as vinyl ester, phenol, polyimide, polyethylene, polypropylene, polystyrene,
Although various synthetic resins such as ABS, polyamide, polycarbonate, polyethylene terephthalate, polybutylene terephthalate, polyacetal, polyacrylate, polyphenylene oxide, polyphenylene sulfide, polyether sulfone, polyether ketone, polyether imide and the like can be used, The most common of them are epoxy resins, polyester resins, polyamide resins, acrylic resins, polycarbonate resins, etc., although the impregnation amount is not limited,
Generally, 50 to 10,000 parts by weight, more generally 100 to 100 parts by weight, relative to 100 parts by weight of carbon long fiber roving is used.
It is in the range of 2000 parts by weight.

By the way, when continuous impregnation with a long carbon fiber strand is carried out by the above-mentioned method, friction during the process of passing the strand through a fiber-spreading / impregnation roller or the like, or withdrawing from the exit nozzle of the impregnation head. A fluffing may be generated from the roving bundle due to ironing and the like, and the fluff may be attracted and entangled immediately before the exit nozzle, and the fluffs may grow one after another in a short time to form the nodule.

Therefore, as a result of studying a solution to this problem, a twisting mechanism (for example, a rotation mechanism) is provided on the downstream side of the impregnation head 9 in the impregnation device 5, and the twisted resin impregnated strand is taken up. By doing so, the fluff that has begun to be entangled immediately before the outlet nozzle is taken into the twist and is pulled out to the outside of the outlet nozzle, and as a result, the formation of the nodule immediately before the outlet nozzle is achieved. Prevented, even when performing a continuous operation for a long time, without causing trouble of taking the resin-impregnated strand,
It was found that excellent productivity was obtained.

Furthermore, by imparting such a twist, the bubbles in the fiber gap are expelled, and the forced moving force acts on the impregnated resin, so that the resin impregnability is enhanced.

In the long fiber strand produced as described above, however, the roving bundle is contained in a twisted state (helical state), so that the tensile elastic modulus is not as large as expected. For example, this is a stampable sheet. There is a problem in using it as a unidirectional reinforcing material. Further, when applied to the filament winding method, it is desired to form a strip-shaped long fiber strand, but the long fibers contained in the twisted state as described above do not form a smooth surface even when flattened and flattened on the surface. Therefore, the product obtained by, for example, winding in a pipe shape does not become uniform over the entire length, resulting in non-uniform strength in the product, quality variation among products, and the like.

Therefore, when adopting such a twisting method, the once produced strand is reheated to restore plasticity, and in that state, twisting in a direction opposite to the twisting direction is applied to elongate the long fiber. It is desired to return to the state. Then, the one that is re-cured in such an extended state has an improved tensile elastic modulus, and the one that is flattened and crushed and re-cured becomes a smooth strip-shaped strand, so that the above-mentioned problems can be solved. Moreover, the long fiber strands obtained by performing the untwisting in this manner have a high tensile elastic modulus because the carbon long fibers are present in a state of maintaining the straightness, and exhibit excellent physical properties as a unidirectional reinforcing material. . When applied to the filament winding method, a smooth strip-shaped long fiber strand can be obtained, and a filament winding product having uniform and good physical properties can be produced.

[0025]

EXAMPLES Hereinafter, the constitution and effects of the present invention will be described in more detail with reference to examples, but the present invention is not limited by the following examples and may be adapted to the gist of the preceding and following. It is of course possible to appropriately change and implement the range, and all of them are included in the technical scope of the present invention.

Using the apparatus as shown in FIG. 1, a Ni-plated carbon long fiber strand was produced under the following conditions, and the obtained strand was cut into a length of 6 mm to produce a carbon long fiber pellet. . Then, injection molding was carried out using the pellets under the following conditions, and the physical properties of the obtained injection-molded product were examined, and the results shown in Table 1 were obtained.

(Conditions for producing long carbon fiber strands) Carbon fiber roving: 12 K roving with a diameter of 7 μm
(12000) 2 metal plating: Ni plating (plating solution composition: NiSO ₄ · 7H ₂ O 150kg
/ M ³ , NH ₄ Cl 15 kg / m ³ , H ₃ BO ₄ 15 kg / m ³ , plating conditions: current density 50 kg /
m ³ , electrode Ni, coating weight: 0.2-0.3 g / m (carbon fiber 100
Corresponding to 30 to 40 parts by weight of Ni relative to parts by weight) Impregnating resin: Polycarbonate resin (trade name "Panlite L1250" manufactured by Teijin Chemicals Ltd.) Impregnation amount ... 400 parts by weight (100 parts by weight of carbon long fiber) Impregnation condition: Resin temperature 300 to 310 ° C. Pulling speed 5 m / min Nozzle diameter 2.2 mmφ

(Injection molding conditions) Molding machine "SG220" manufactured by Sumitomo Heavy Industries, Ltd. Cylinder temperature 280 to 330 ° C Mold temperature 120 ° C Screw rotation speed 50 rpm Screw diameter 45 mmφ Injection speed 100 mm / sec Cooling time 30 sec

(Molded product shape) 150 mm wide x 150 mm deep x 20 mm deep lunch box type wall thickness 1.2 mm (Performance test method) Bending test (bending strength, bending elastic modulus): test piece width 10 mm x length 50 mm × Thickness 1.2m
m Crosshead speed 4mm / min Roundness of support part 2.5mmR Roundness of presser part 5.0mmR Span between support parts 40mm Conductivity: SRIS2301 Voltage / current method Radio wave shielding property: KEC (Kansai Electronics Industry Promotion Center) method Magnetic wave shielding property: KEC (Kansai Electronics Industry Promotion Center) method

[0030]

[Table 1]

As is clear from Table 1, according to the present invention, it is possible to produce carbon long fiber reinforced resin strands excellent in mechanical properties and radio wave shielding property and magnetic shielding property with good productivity.

[0032]

EFFECTS OF THE INVENTION The present invention is configured as described above, and in the production line of fiber reinforced resin, the surface of the carbon long fiber used as the reinforcing fiber is metal-plated, which results in high strength and good conductivity. It is possible to manufacture the carbon long fiber reinforced synthetic resin strand with good productivity, which can obtain a fiber reinforced resin molded product having characteristics such as radio wave shielding property and magnetic shielding property.

[Brief description of drawings]

FIG. 1 is a schematic explanatory view illustrating a manufacturing method according to the present invention.

[Explanation of symbols]

 1a, 1b, ... Carbon long fiber roving 1 Roving bundle 2 Metal plating tank 3 Metal plating solution 4 Drying device 5 Synthetic resin impregnation device 5a Synthetic resin supply device 6 Post-processing device 7 Take-up roller 8 Winding device

Claims (4)

[Claims] 1. A carbon long fiber is aligned and introduced into a synthetic resin bath container, and the resin-impregnated carbon long fiber is drawn from an outlet nozzle of the synthetic resin bath container while impregnating the carbon long fiber with the synthetic resin. Thereby, in the method for producing a carbon long fiber reinforced synthetic resin strand, the carbon long fiber is subjected to metal plating on the surface while being opened and spread, and then the resin is impregnated by introducing it into the synthetic resin bath container. A method for producing a long carbon fiber reinforced synthetic resin strand, comprising: 2. The metal plating is Ni plating.
The method for producing a carbon long fiber-reinforced synthetic resin strand according to 1. 3. The carbon long fiber reinforced synthetic resin according to claim 1, wherein after the metal plating is applied, the surface of the plating layer is oxidized and then introduced into the synthetic resin bath container for resin impregnation. Strand manufacturing method. 4. The production of a carbon long fiber reinforced synthetic resin strand according to claim 1, wherein the resin-impregnated carbon long fibers drawn out from the synthetic resin bath container are taken in a twisted state. Method.