JPH04173325A - Method and device for producing fiber reinforcing material - Google Patents

Abstract

PURPOSE: To impregnate a fiber bundle with a liquid resin by introducing a liquid-like resin material between relatively moving approached surfaces by a shearing force to receive a shearing force before impregnating, thereby lowering a viscosity of the material. CONSTITUTION: A web 10 of a glass fiber bundle is supplied from a drum 11 to an impregnation head 18 via a preheating chamber 12 and a width enlarging unit 13. A resin material 16 is supplied from a hopper 17, melted by an extruder 15, and supplied to the head 18. A melted resin of not shearing state is supplied via a supply cavity 23 of the head 18, and supplied to an annular space between two cylindrical surfaces 26 and 27 via a port 25. In the space between the surfaces 26 and 27 rotating at one side, a resin material 29 receives a shearing operation to lower its viscosity. The resin material is supplied to an impregnation region 31 via a supply channel 30, and the web 10 is passed to an impregnation region 31, and the bundle is impregnated with the viscosity lowered melted resin. A resin-impregnated web 10b is sent to a cooling unit 18.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method and apparatus for producing fiber reinforced materials. In particular, the present invention relates to a method and apparatus for producing fiber reinforced materials, which materials are formed from reinforcing fiber bundles in which the individual fibers are surrounded by a resin material and bonded with a matrix-forming resin material.

The main l in manufacturing this kind of product? A FI problem is the high viscosity of certain matrix-forming materials. Because the individual fibers in a fiber bundle are in such close contact with each other, it is difficult to infiltrate the bundle with resin material to surround all of the individual fibers. However, in terms of product properties such as strength, stiffness, chemical resistance, etc., this is a must.

(Conventional technology) Many methods have been tried to solve the above problem.

In one solution, the fiber bundles are passed through a so-called cloth die, where the molten or liquid resin is allowed to penetrate the web of fiber bundles passing through the die. In the so-called powder method, a web of fiber bundles is passed through a bed of thermoplastic resin particles, so that the resin particles stick to the web of fiber bundles and are melted in a subsequent step. In the solvent method, the fiber bundle is immersed in a resin dissolved in a liquid medium.

The cross-to-rad dye method has proven ineffective in impregnating fiber bundles with thermoplastic resin. The reason is that not every fiber is individually surrounded by resin material. Powder methods involve multiple processing steps that are extremely difficult to synchronize, are uneconomical to purchase, operate, and damage the reinforcement. Solvent methods require a drying step, which is uneconomical, creates environmental problems, wastes time, and limits production rates. Furthermore, the quality of the product is also reduced due to the presence of voids remaining after removal of the solvent.

(Problems to be Solved by the Invention) The above-mentioned conventional technology has the above-mentioned problem in that all the fibers constituting the fiber bundle are impregnated with reinforcing resin. , which is a problem to be solved by the present invention.

(Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention provides a method and apparatus for impregnating reinforcing fibers in the form of fiber bundles with a resin, thereby wrapping individual fibers in a bonding resin. The present invention is based on the known phenomenon that pseudoplastic materials subjected to shear forces experience a decrease in viscosity. This phenomenon, known as gradual thinning, is common to a variety of emulsions, dispersions, suspensions, and other materials, including thermoplastic melts and thermoset solutions. The tendency of shear-thinning ribbons varies with the level of shear stress acting on the material. At low stress stages, a small response is obtained, at intermediate shear stress steps the response increases dramatically, and at very high stresses the response decreases as the material approaches its lowest viscosity. , regress to a lower level.

The typical range of viscosity for thermoplastic resin melts is 102 to 106 PaS, and that for thermosetting resin solutions is 100 PaS.
~5000 PaS. In impregnating reinforcing fibers, 1
~10 Pas range is ideal, common magnitude is 10 PaS, and in some cases 10” P
It is also acceptable for aS. Typical shear ranges for polymer melts and solutions are 10-1 to 1061/S, and maximum response ranges are 100 to 1041/S.

The method according to the invention involves impregnating fiber bundles with a molten or liquid resin in the production of fiber-reinforced materials, where the material consists of one or more fiber bundles and each The present invention involves a method in which the fibers are surrounded by a matrix resin, a continuous web of one or more fiber bundles is impregnated with a molten or liquid resin, and the resin is hardened by cooling or chemical reaction. The method is characterized in that, prior to said impregnation, said molten or liquid resin material is placed between adjacent relatively moving surfaces and subjected to shear forces.

According to an advantageous embodiment according to the invention, one of said surfaces is a fixed surface and the other surface can also be a moving surface. An essential requirement of the invention is that the marking surfaces are close to each other;
They are in a relationship that allows them to move relative to each other.

According to an advantageous embodiment of the method according to the invention, one of the movable surfaces consists of a continuous web of fiber bundles to be impregnated. In this case, the resin to be impregnated is guided between two fixed or movable surfaces, where both surfaces rotate together, only one rotates, or both rotate in different directions relative to each other. In this way, the resin is sheared in the darkness, and the shearing force acting on the impregnated resin reduces the viscosity of the resin, making it easier to wrap individual fibers with the resin.

According to an advantageous embodiment of the invention, both surfaces are cylindrical and the resin flows between the surfaces to provide a settling effect and reduce the viscosity.

With the method of the invention any fiber-reinforced material can be produced, where the fibers are in the form of bundles. The fibers can be any type of fiber that is bonded with a matrix resin. Such products are, for example, fiber-reinforced granules for injection molding or other processes, prepregs or preimpregnated materials for additive processes such as pultrusion, filament winding, tablelaying, etc.

Suitable fibers for the invention are thus glass fibers, carbon fibers and aramid fibers and thermoplastic* fibers. The most common fibers used are bundled glass fiber products, which can be used as single bundles or in the form of woven products, such as glass fiber rovings. The bundle has a diameter of 10-17 μ-
Contains thousands of individual fibers.

The resin materials used to bond fiber reinforced products are thermoplastic or thermoset resins that are melted and impregnated into the fiber bundle, and then cured by heat or chemical reaction.

Suitable thermoplastic resins include, among others, olefin homopolymers and copolymers, vinyl chloride homopolymers and copolymers, polyethylene terephthalate, acrylonitrile polymers and copolymers, polyamides or copolyamides, polymeric redehydes. Thermoplastic polymers, polycarbonates, mixtures of polysulfone and two or more of the aforementioned polymers, or other thermoplastics that generally exhibit a reduction in viscosity on shear action.

The present invention also relates to an apparatus for impregnating reinforcing fibers in the form of fiber bundles in the production of fiber-reinforced materials, the material consisting of one or more bundles, each fiber being made of a matrix resin. The apparatus of the invention is further comprised of means for applying a shearing force to said molten or liquid resin prior to said impregnation into said molten or liquid resin, said means comprising means for applying a shear force to said molten or liquid resin between two adjacent surfaces. said molten or liquid resin being forced through and subjected to shear forces; and means for supplying said molten or liquid resin material between said surfaces.

According to an advantageous embodiment of the device according to the invention, at least one or both of the surfaces are moving surfaces.

According to an advantageous embodiment of the device according to the invention, both surfaces are cylindrical.

According to an advantageous embodiment of the device according to the invention, both surfaces are flat, and the surfaces consist, for example, of two flat-faced discs, both of which rotate in opposite directions, such that both surfaces are planar. Molten or liquid resin is injected between the rotating surfaces of.

According to an advantageous embodiment of the device according to the invention, the two surfaces define an annular space between the two cylindrical surfaces, and one or both of the surfaces are rotatable.

According to an advantageous embodiment of the device according to the invention, the means for contacting the fiber bundle impregnated with resin whose viscosity is reduced by shearing action with the resin has at least one feed channel communicating with the annular space.

Further, the supply channel may have a circular cross-sectional shape, a rectangular cross-sectional shape,
Others are optional.

According to an advantageous embodiment in the device according to the invention, the feed channel is at least one or more slits leading into the wall of the impregnation head surrounding the annular space.

According to an advantageous embodiment of the device according to the invention, the impregnation head is connected to the outlet of the extruder.

According to an advantageous embodiment of the device according to the invention, the outer surface of the impregnation head is curved or flattened in the region of impregnation.

The invention will be further illustrated, but not limited, with reference to the enclosed drawings, in which: FIG.

(Example) In FIG. 1, a web 10 of glass fiber bundles is attached to a drum 1.
1 is supplied to an impregnation head 18 via a preheating chamber 12 and a widening device 13. In the widening bag 213, the web 10 is threaded through a set of rolls 14, so that the fibrous web is threaded between the top and bottom of said rolls. In this way, the bundled fibers are loosened and widened, thus facilitating impregnation in the impregnation stage. However, this widening device 13 is not essential and does not constitute a requirement of the present invention. The impregnation head 18 is connected to the extruder 15, and the resin material 16 to be impregnated into the extruder
is supplied from the hopper 17. Extruder 15
At , the resin is melted and fed to the impregnation head 18 according to the invention.

The resin-impregnated band or web 10b of fiber bundles is then fed to a cooling unit 19 where the molten resin is hardened by cooling. The curing action is also carried out by a chemical reaction.

The resin-impregnated and hardened fiber bundle is sent from the cooling unit 19 to the chopper 20, where the impregnated web is cut into pieces 21 of appropriate length and packaged or subjected to molding production into molded products. It becomes like this. It is also possible to form continuous fiber-reinforced products with the method and apparatus of the invention, in which case the impregnated web can be cut to the desired length or uncut. be made into a genius.

The web 10 can be conveyed in the apparatus of FIG. 1 by means of suitable tensioning devices. A bell 1-drive tensioning device 22 is shown diagrammatically in FIG.

FIG. 2 shows details of the impregnation head 18 in FIG. 1. Inside the impregnation head 18 is provided a feed cavity 23 through which unsheared molten resin is fed from the extruder 15 . Resin from the cavity 23 is fed via the boat 25 into the annular space between the two cylindrical surfaces 26,27.

In this embodiment, outer surface 26 is a fixed surface, and
The inner surface 27 is the moving surface. This moving surface 27
is constituted by the outer surface of a rotating annular body 28, which rotates in the direction indicated by arrow A. However, this rotational action is not essential. In the annular space between the rotating surfaces 26, 27, one relative to the other, the resin material 29 is subjected to shearing action, reducing its viscosity.

The sheared resin material between the surfaces 26, 27 is then discharged through the feed channel 30 and into the impregnated region 3.
1. The fiber bundle web 10a has an impregnated region 31
There, the molten resin with a reduced viscosity penetrates into the fiber bundle, permeates all the fibers that make up the fiber bundle, and envelops them.

The resin-impregnated fiber bundle web 10b is then sent to the cooling unit 18 shown in FIG.

The viscosity-reducing shearing action shown in FIG. 2 takes place between two surfaces, one of which is stationary and the other rotating. However, it is also possible to make both surfaces rotatable and to rotate one surface 26 in a direction opposite to that of the other surface 27 to supply resin between them. Third
An example of this is shown in the figure.6 The device shown in Fig. 3 differs from the example shown in Fig. 2 in that the shear space is formed between two rotating surfaces 26, 27. In this case, the surface 26 is the inner surface of the annular body 32 and rotates in the direction opposite to the annular body 28 (arrow B), resulting in a more efficient shearing action.

Furthermore, a plurality of shearing spaces can be formed sequentially, and the resin material supplied to the impregnating head 18 in FIGS. 1 to 3 is
Shearing can also be applied by preheating by other means to reduce the viscosity or by passing through a capillary tube.

(Effects of the Invention) As described above, according to the present invention, since a fiber-reinforced molded article is molded, the reinforcing fibers can be completely impregnated with resin, and the reinforcing fibers are not made in a resin-poor state. It is possible to produce reinforced fiber materials that can be molded into high-quality fiber-reinforced molded objects.

[Brief explanation of drawings]

FIG. 1 is a main drawing of an apparatus according to the invention applied to the continuous production of fiber-reinforced granules. 2 and 3 are respectively schematic cross-sectional views of an apparatus for impregnating a web of glass fiber bundles with matrix resin according to the invention. lO... Web 10a... Fiber bundle web 10b... Resin-impregnated web 11... Drum 12... Preheating chamber 13... Widening device 14... Roll 15...Extruder 16...Resin material 17...Hopper 18...One impregnation head...Cooling unit 20...Chopper 21...- ...Piece 22...Tensioning device 23...Feeding cavity 25...Boat 26.27...Surface carrying out shearing action 28.32...
- Annular body 29... Resin material 31... Supply channel

Claims (15)

[Claims] (1) A method in which fiber bundles are impregnated with molten or liquid resin when producing fiber-reinforced materials, and the material consists of one or more fiber bundles, and each fiber is made of matrix resin. A continuous web (10; 10a) of one or more fiber bundles is impregnated with a molten or liquid resin (32, 33), and the resin is hardened by cooling or a chemical reaction. A method characterized in that, before impregnation, said molten or liquid resin material (29) is fed between two adjacent surfaces (26, 27) in relative movement and subjected to shear forces. 2. A method according to claim 1, characterized in that one of said surfaces is a fixed surface (26) and the other surface is a movable surface (27). (3) A method according to any one of claims 1 to 3, characterized in that both said surfaces (26, 27) are movable surfaces. (4) A method according to any one of the preceding claims, characterized in that both of the surfaces (26, 27) are cylindrical surfaces. (5) A method according to any of the preceding claims, characterized in that the resin matrix is a thermoplastic material. (6) Thermoplastic matrix materials include olefin homopolymers and copolymers, vinyl chloride homopolymers and copolymers,
polyethylene terephthalate, acrylonitrile polymers and copolymers, polyamides or copolyamides, thermoplastic polymers of formaldehyde, polycarbonates,
7. Process according to claim 6, characterized in that it is selected from the group consisting of polysulfone and a mixture of two or more of the abovementioned polymers. (7) A device for impregnating fiber bundles with molten or liquid resin (24, 29) in producing fiber-reinforced materials, the material being composed of one or more fiber bundles, Each fiber is surrounded by a matrix resin, and prior to said impregnation operation, means are provided for applying a shearing force to said molten or liquid resin (29), said means comprising two adjacent surfaces in relative movement. (26, 27) and the surface (
26, 27), the melted or liquid resin (29)
said molten or liquid resin is injected between said surfaces and a shearing force is applied during impregnation. (8) Device according to claim 7, characterized in that at least one or both of said surfaces (26, 27) are movable. (9) Device according to claims 7 to 8, characterized in that the surfaces (26, 27) are cylindrical surfaces. 10. Device according to claims 7 to 9, characterized in that the surfaces (26, 27) define an annular space between two cylindrical surfaces, one or both of which rotate. (11) The means for bringing the fiber bundle into contact with the molten resin, which has already been subjected to shearing forces and whose viscosity has been reduced to a certain extent, includes one or more feed channels (30
), the channel communicating with the annular space. 12. Device according to claim 11, characterized in that the feed channel (30) has a circular, square or other cross-sectional shape. (13) The supply channel (30) comprises one or more slits cut in the wall of the impregnation head (18) surrounding the annular space. Apparatus according to paragraph 12. (14) The impregnation head (18) is connected to the extruder (1).
Claim 1 characterized in that it is connected to the outlet of 5).
Device according to Section 3. 15. Device according to claim 13, characterized in that the impregnation head (18) is curved or flat in the impregnation area (31).