JPH04125110A - Manufacture of fiber reinforced resin molding material - Google Patents

Abstract

PURPOSE:To prevent reinforced fiber from scattering into the atmosphere without providing particularly a cutting device for reinforced fiber by feeding the reinforced fiber in the long fiber state into a kneading device while a resin material is kneaded by means of a multi-screw kneading device, cutting the reinforced fiber in the kneading device and dispersing the same into a resin material as the reinforced fiber of short fiber shape. CONSTITUTION:Thermosetting resin and an inorganic filler are fed quantitatively and continuously at the constant ratio into a casing 11 through respective feeding inlets 13a and 13b. Both materials are fed into a filler kneading section M1 while both materials are mixed in a carrying section T1. Then, the both materials are kneaded strongly in a kneading section M1 while being pushed back at a backflow section R1. A kneaded material is fed into a carrying section T2 by the extrusion pressure from the upstream side at the carrying section T1. Further reinforced fiber is fed from a reinforced fiber feeding section 13c provided at the carrying section T2 into the casing 11 continuously. Said materials are kneaded strongly at a reinforced fiber kneading section M2 by the action of a backflow section R2, and a glass roving F is cut into various kinds of dimensions in the casing 11.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for manufacturing a fiber-reinforced resin molding material in which reinforcing fibers are uniformly dispersed. Therefore, the present invention relates to a method for producing a fiber-reinforced resin molding material that can prevent reinforcing fibers from scattering into the outside air.

[Prior art] 8j Greasy material coarsely reinforced fiber (additionally inorganic filler if necessary)
When manufacturing fiber-reinforced resin molding materials, such as BMC (bulk molding compound), in which the resin material is dispersed, it is necessary to disperse The reinforcing I#i fibers in the form of cut short fibers are mixed and kneaded using, for example, a double-arm kneader to uniformly disperse the reinforcing fibers. The above is a method for producing Hatch-2 BMC, but when continuous kneading is used, the above-mentioned material may be quantitatively fed into a screw kneading device and kneaded.

Glass fibers are often used as the reinforcing fibers, and after cutting glass roving brought in from a glass fiber manufacturer into short fibers of arbitrary length using a chopper device, they are charged into the kneading device through a short glass fiber feeder. was common.

However, the conventional method of installing a dedicated chopper for cutting glass rovings increases equipment costs and manufacturing costs.
. . . increased, and more importantly, short fibers were scattered into the air from the chopper device and short glass fiber feeder, which worsened the working environment in the factory.

[Problems to be Solved by the Invention] Therefore, the present inventors have discovered that there is no need to install a chopper device, the short fibers are not scattered into the outside air, and the reinforcing fibers exhibit the expected reinforcing performance. The present invention was completed after repeated research aimed at providing a method for manufacturing a fiber-reinforced resin molding material that is dispersed in a resin material in an appropriate length.

[Means for Solving the Problems] The present invention, which has achieved the above object, has a multi-screw kneading device that kneads a resin material and supplies reinforcing fibers in the form of long fibers to the kneading device. The gist is to cut the fibers in the kneading device and disperse them in the resin material as reinforcing fibers in the form of short fibers.

[Function] In the present invention, since the reinforcing fibers are charged into the kneading device as long fibers, there is no need for a chopper device or a glass short fiber feeder, and the fibers cut into short fibers are There is no longer any scattering. In addition, the above-mentioned long fibers are strongly kneaded in a multi-screw kneading device, so that they are cut and dispersed into short fibers with each panicle length ranging from about 1 mII'1 to several + mm. This method is fully comparable to that of the previous method.

In the multi-screw kneading device mentioned above, it is preferable to use one that is equipped with a backflow screw on the downstream side of the kneading screw.This allows for more reliable cutting of the long fibers and also reduces the amount of damage to the resin material. This enables uniform dispersion.

[Example] Example of the structure of the kneading device used in the present invention. FIG. 1 is a vertical cross-sectional view of a kneading device with two screws, and FIG.
It is a sectional view taken along the line I-II. The kneading device 1 has a casing 11 and rotating screw shafts 15a and 15b arranged in mesh with each other as main components.

A resin material supply section 13a, a filler supply section 13b, and a reinforced i# fiber supply section 13c are formed in the casing 11, and thermosetting resin material, inorganic filler, and reinforcement are supplied via a quantitative supply device, a hopper, etc. (not shown). Fibers (hereinafter also simply referred to as both materials) are quantitatively charged into the casing 11. In the reinforcing fiber supply section 13c, the casing 11 is unwound while the wound glass roving F is unwound.
Continuously supply a fixed amount to the inside. At this time, the glass roving F is fed into the casing 11 so as to be dragged along with the transport flow of the resin material. Therefore, no special supply means are required. Of course, in order to actively insert the glass roving F into the casing 11, the use of a separate supply means such as a roller feeder is not excluded.

Further, a deaeration port 18 and a molding material discharge port 14 are formed on the downstream side of the casing 11 in the material conveyance direction.
8 is connected to a vacuum pump 19, and on the downstream side of the discharge port 14, a shape retaining device 2 is provided to adjust the shape of the molding material if necessary. Furthermore, a water cooling chamber 12 is formed in the casing 11, into which a cooling medium such as water is introduced to prevent deterioration of the thermosetting resin.

The other screw shaft 15a is disposed so as to mesh with the other in parallel.
, 15b are formed with conveying blades 16A, kneading blades 16B, and backflow blades 16C. The conveying blade 16A transfers the entertainer material or molding material to the discharge port 14 by rotation of the screw shaft.
It is a spiral blade that is moved in the direction of the installation position (see Fig. 3). Further, the kneading blades 16B are in the form of an elliptical or polygonal plate as shown in FIG. 4, and the kneading blades 16B, 16B that are meshed with each other strongly knead the material so as to crush the material. Furthermore, as shown in FIG. 5, the backflow blade 16C is a spiral blade that runs in the opposite direction to the conveyance blade 16A, and conveys the molding material, etc. in the opposite direction to the conveyance of the conveyance blade 16A, that is, in the direction of pushing it back. This results in a very large kneading effect.

In the example of FIG. 1, the conveying blade i6A, the kneading blade 16B, the backflow blade 16C, the conveyance blade 16A, the kneading blade 16B, the backflow blade 16C, and the conveyance blade 16A are arranged in order from the left side, and the arrangement position of each blade is The transport section T1, the filler kneading section M1, the backflow section R8 and the transport section T2, the reinforcing fiber kneading section M2, the backflow section R2 and the transport section T are constructed. The above-mentioned conveyance section, kneading section, and backflow section may be arranged in any order, or may be omitted in any order.

Note that the shapes of the blades 16A to 16C on the rotating screw shafts 15a and 15b are not limited to those shown in FIGS. 3 to 5, and the pitch, height, width, etc. of the blades can be changed as desired depending on the desired degree of kneading. It may be changed to . The helical direction of each screw shaft 15a, 15b may be the same direction as shown in FIG. 6(^) or the different direction as shown in FIG. 6(B). (different direction).

Examples of Materials Used in the Invention As the thermosetting resin, for example, a mixture of a polymer having radical polymerization activity, a radical polymerizable polymer, and a radical polymerization initiator can be used. Examples of the polymer having radical polymerization activity include, but are not limited to, unsaturated polyesters, epoxy-modified poly(meth)acrylates, and the like. The radical polymerizable polymers include, but are not limited to, aromatic vinyl compounds such as styrene, vinyltoluene, α-methylstyrene, methyl (meth)acrylate,
- (meth) such as hydroxyethyl (meth)acrylate
Acrylic acid ester etc. are recommended. The mixing ratio of these is preferably such that 50 to 90 fI amount % of the polymer having radical polymerization activity, 50 to 10 weight % of the radical polymerizable monomer, and a trace amount of the radical polymerization initiator are included. Add thickening agent, coloring agent, mold release agent, etc. However, there is no limit to the type of resin material that can be used in the present invention.

On the other hand, examples of inorganic fillers include powders of calcium carbonate, clay, aluminum hydroxide, glass, silica, etc., or mixtures thereof. On the other hand, non-limiting examples of reinforcing fibers include glass fibers, carbon fibers, aramid fibers, etc., and the number of fiber bundles is arbitrarily selected depending on the manufacturing speed of the molding material. Note that there are no restrictions on the types of these auxiliary materials.

EXAMPLE OF MOLDING MATERIAL PRODUCTION METHOD An example of manufacturing a bulk molding compound (hereinafter referred to as BMC) using the kneader 1 shown in FIG. 1 will be described below. The above thermosetting resin and inorganic filler are continuously and quantitatively charged into the casing 11 at a constant ratio through the respective supply ports 13a and 13b. In the conveyance section T, both materials are mixed and fed to the filler kneading section M1. Next, both materials are strongly kneaded in the filler kneading section M1 while being pushed back in the backflow section R1. The kneaded material is then sent to the transport section T2 by extrusion pressure from the upstream side of the transport section T1. Furthermore, reinforcing fibers are continuously charged into the casing 11 at a rate of 20 to 300 kg per 1000 kg of molding material from the reinforcing fiber supply section 13c provided in the conveying section T2. These materials are strongly kneaded in the reinforcing fiber kneading section M under the action of the backflow section R2 in the same manner as described above, and the glass roving F is cut into various sizes within the casing 11. Then, as the molded material 1, the conveying section T3 is adjusted slightly and the discharge port 1 is
Moved in 4 directions. In addition, degassing 01 in the transport section T3
It is recommended that the kneaded material be exposed to a reduced pressure atmosphere in the degassing section S provided with the molding material No. 8 to evacuate the air mixed in the kneaded material to obtain a molding material with fewer bubbles. The molding material continuously discharged from the discharge port 14 is processed into a lump or sheet shape through the shape retaining device 2 and recovered as a molding resin material.

[Effects of the Invention] Since the present invention is constructed as described above, the entire kneading device can be made compact, and the scattering of short fibers into the air can be completely prevented, thereby preventing deterioration of the environment. . Furthermore, reinforcing fibers of each ear length are uniformly dispersed in the molding material, making it possible to produce a molding resin material with stable strength.

[Brief explanation of drawings]

Fig. 1 is a side sectional view showing the implementation of the kneading machine used in the present invention, Fig. 2 is a sectional view taken along the line II-II in Fig. 1, and Figs. 3, 4, and 5 are kneading blades. An explanatory diagram showing an example of the shape of
FIGS. 6(A) and 6(CB) are explanatory plan views showing examples of combinations of kneading blades on the rotating screw shaft. 1...Kneading device 2...Shape retaining device 11...
Casing 15a, 15b... Rotating screw shaft] 8... Deaeration port 19... Vacuum pump applicant Nippon Shokubai Chemical Co., Ltd.

Claims (1)

[Claims] While kneading the resin material with a multi-screw kneading device, reinforcing fibers are supplied in the form of long fibers to the kneading device, and the reinforcing fibers are cut in the kneading device to form reinforcing fibers in the form of short fibers in the resin material. A method for producing a fiber-reinforced resin molding material, which comprises dispersing the material.