JPH08207098A - Molding of resin material incorporating glass long fiber and device thereof - Google Patents

Abstract

PURPOSE: To form a molding with excellent impact resistance property by using a long fibrous pellet consisting of a resin containing a glass long fiber. CONSTITUTION: A long fibrous pellet 32 consisting of a resin containing a glass long fiber is supplied to a plasticizing cylinder 12 with a conical cylinder hole 12a from a hopper 14. In addition, the long fibrous pellet 32 is caught into a screw groove by a screw 16 formed to a larger screw groove depth than the length in an axial direction of the long fibrous pellet 32, and moves through the screw groove. Thus, the long fibrous pellet 32 is fused and kneaded, then is extruded from the plasticizing cylinder 12 into a material storage chamber M in an injection cylinder 21, and a specified amount of a molten material is stored by moving an injection plunger 22 in the injection cylinder 21 backward. Thus, the injection plunger 22 is forcibly moved forward. Further, the molten material is injected into opened dies 38, 40 or the dies 38, 40 in the process of closing. Finally, the dies are clamped and a compression force is applied to the molten material for molding.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for molding a resin material containing long glass fibers.

[0002]

2. Description of the Related Art As a conventional molding method using a resin material containing long glass fibers, a stampable sheet which has been molded into a sheet shape in advance is supplied to a press molding machine and molded into a predetermined shape by pressing. There is something. As a result, a molded article having high impact resistance characteristics making use of the characteristics of long glass fibers is manufactured.

[0003]

However, in such press forming using a conventional stampable sheet, it is necessary to prepare a stampable sheet separately, or the sheet is automatically formed in the press forming machine with its shape adjusted. There is a problem that it is difficult to carry in.
Therefore, using an injection molding machine that is easy to fully automate,
If such molded products can be manufactured, it is expected that production efficiency will be improved and cost reduction will be facilitated. As an injection molding machine, the screw is rotated to plasticize and store the molding material, and then the screw is axially moved with the screw stopped to inject the stored molding material into a mold. Such an in-line screw type injection molding machine is generally used. However, even if an attempt is made to plasticize and mold a resin material containing long glass fibers using such a conventional in-line screw type injection molding machine, the long glass fibers in the molding material will be damaged during plasticization and weighing. There is a problem in that it is easily received and the impact resistance of the molded product is likely to deteriorate. The present invention aims to solve such problems.

[0004]

The present invention uses a plasticizing device equipped with a conical screw, a plunger type metering / injecting device, and a mold clamping device to determine the screw groove depth on the screw supply side. A plasticizing device formed deeper than the length of the pellet melts and kneads the molding material, and a plunger-type metering / injection device that can increase the cross-sectional area of the flow path measures the molten material, and the mold is not completely closed. The above-mentioned problem is solved by injecting the molten material into the mold and performing the mold clamping after the injection is completed. That is, the method for molding the resin material containing long glass fibers according to claim 1 of the present invention is
Long fiber pellets made of resin containing long glass fibers are supplied from a hopper to a plasticizing cylinder with a conical cylinder hole, and then a conical screw is rotated in the plasticizing cylinder to supply long fiber pellets. The depth of the groove on the side is larger than the axial length of the long fiber pellet, and it is bitten into the screw groove and moves in the screw groove where the screw groove depth gradually decreases from the supply side to the discharge side. To melt and knead, then extrude the molten material from the plasticizing cylinder into the injection cylinder by a predetermined amount, store the injection plunger in the injection cylinder by retracting it, and then forcibly advance the injection plunger. By injecting the molten material into the mold that is not completely closed, and then closing and closing the mold to melt It is characterized by compression molding into a predetermined shape charge. The apparatus according to claim 2 for carrying out the method according to the invention also comprises a hopper (14), a plasticizing cylinder (12) integral therewith, and a screw (16) rotatably fitted thereto. The plasticizing device (10), the injection cylinder (21), the injection plunger (22) axially movably fitted to the injection cylinder (21), and the nozzle (2) provided at the front of the injection cylinder (21).
The object is to have a metering / injecting device (20) having 6) and a mold clamping device (30) having molds (38 and 40), and the plasticizing cylinder (12) is The cylinder hole (12a) is formed in the shape of a conical hole whose diameter gradually decreases from the supply side toward the extrusion side, and the screw (16) has a contour formed by the outer periphery of the flight portion (16b) as a cylinder hole ( 12a) has a conical shape corresponding to that of the screw groove (16
In c), the groove depth (hf) of the supply section is set to be larger than the axial dimension (L) of the long fiber pellet (32) made of a resin containing long glass fibers, and the flight section (16b). ) Except the shaft part (16a) is formed with a constant outer diameter over the entire length, and the screw groove depth is formed so as to gradually decrease from the supply side to the extrusion side. The injection device (20) performs measurement by retracting the injection plunger (22) by the molten material extruded from the plasticizer (10), and after the completion of the measurement, the injection plunger (22) is forced to advance. As a result, the molten material can be ejected from the nozzle (26), and the mold clamping device (30) is a measuring / injecting device (20) when the molds (38 and 40) are not completely closed. Melt from Material is injected into the mold (38 and 40), after the completion of injection, it is characterized in that it is configured to compress molding the molten material into a predetermined shape by performing mold closing, mold clamping. The reference numerals in parentheses indicate the corresponding members of the embodiment.

[0005]

The long-fiber pellets, which are supplied to the plasticizing cylinder and are made of a resin containing long-fibers and have a longer length than usual, are bite into the screw grooves of the supply section. At this time, since the screw groove depth of the supply portion is formed to be larger than the length dimension of the long fiber pellet, even the long fiber pellet can be supplied to the screw without being damaged. . The molten material plasticized in the plasticizing cylinder is supplied to a plunger type metering / injecting device, but it is necessary to pass it through an annular channel with a small cross section like an inline screw during metering. Since it does not exist, even a molten material containing long fibers can be weighed without being damaged. After the measurement, the molten material is injected into the mold with the mold not completely closed,
After the injection is completed, the mold is closed and the mold is clamped. As a result, it is possible to efficiently and inexpensively manufacture a molded article having excellent impact resistance characteristics without preparing a pre-processed molding material such as a stampable sheet.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention is shown in FIGS. The screw pre-plasticizer (hereinafter, simply referred to as a plasticizer) 10 includes a plasticizer cylinder 12, a hopper 14 integrally fixed to the plasticizer cylinder 12, and a conical shape rotatably fitted to the plasticizer cylinder 12 having a conical shape. Screw 16 of. The plasticizing cylinder 12 is formed with a conical cylinder hole 12a, a supply port 12b, and an extrusion port 12c. The supply port 12b is in communication with the hopper 14, and the extrusion port 12c is in communication with a flow path 21a of the injection cylinder 21 described later. The hopper 14 has a long fiber pellet 3 made of a resin containing long glass fibers.
2 is supplied. Long fiber pellet 32
Has a length dimension L larger than that of a normal pellet in order to exhibit the characteristics of the long glass fiber.
The shape of the screw 16 will be described in detail later. The screw 16 is rotated by a motor (not shown). A plunger type measuring / injecting device (hereinafter, simply referred to as a measuring / injecting device) 20 is attached to the plasticizing device 10. The measuring / injecting device 20 includes a pressurizing cylinder 18, an injection cylinder 21 fixed integrally with the pressurizing cylinder 18, an injection plunger 22, and a rod 2.
3, a ram 24, a nozzle 26, and a check valve. The injection cylinder 21 has a flow passage 21a and a plunger hole 21b formed therein. The nozzle 26 is attached to the front end portion (left end portion in the drawing) of the injection cylinder 21, and the check valve is the flow passage 21a.
It is located at the inner position 28. An injection plunger 22 is fitted in the plunger hole 21 b of the injection cylinder 21. A pressure cylinder 18 is integrally fixed to the right end portion of the injection cylinder 21 in the figure. A ram 24 is fitted to the pressure cylinder 18. The injection plunger 22 and the ram 24 are integrally connected via a rod 23. The mold clamping device 30 includes a fixed platen 34 and a movable platen 3.
6, the fixed-side mold 38 and the movable-side mold 40. The movable platen 36 is arranged at a position facing the fixed platen 34 so as to be movable in the left-right direction in the drawing. A fixed mold 38 is fixed to the fixed plate 34, and a movable mold 40 is fixed to the movable plate 36. A cavity E is formed by the molds 38 and 40. The movable plate 36 is
It is adapted to be driven by a mold clamping cylinder (not shown). The long fiber pellets 32 are bitten into the plasticizing cylinder 12 from the hopper 14 of the plasticizing device 10 and then melted and kneaded into a molten material, which is extruded from the hopper 14 of the measuring / injecting device 20 in the injection cylinder 21. It is measured, injected through the nozzle 26 of the injection cylinder 21 into the cavity E of the mold clamping device 30, and compression-molded by mold clamping.

As shown in FIG. 2, the screw 16 of the plasticizer 10 has a depth dimension hf of the screw groove 16c of the supply section A on the right side of the figure, and the depth dimension hf of the long fiber pellet 3 used.
It is set to be larger than the dimension L of 2 in the axial direction. In the screw 16, the shaft portion 16a (a portion excluding the flight portion 16b) has a constant diameter dimension d from the supply portion A to the discharge portion C on the left side in the drawing, and the flight portion 16b
However, the diameter is gradually reduced from the supply section A (outer diameter D1) to the discharge section C (outer diameter D2). That is, the outline shape of the screw 16 is a cone shape. The screw groove 16c has a supply portion A (groove depth hf)
Since the groove depth gradually decreases from the discharge portion C (groove depth hm), the cross-sectional area of the screw groove 16c gradually increases from the supply portion A (cross-sectional area Vf) to the discharge portion C (cross-sectional area Vm). It is configured to be small. When these relationships are expressed by mathematical expressions, hf = (D1-d) / 2≤Lhm = (D2-d) / 2 CR = Vf / Vm.apprxeq.2-4. Here, CR is a compression ratio, and is determined using an empirical formula or the like based on the bulk specific gravity of the long fiber pellets 32 used. As the axial dimension L of the long fiber pellet 32, a length dimension of 12 to 48 mm may be used in the future. With the above-described configuration, even when the long fiber pellets 32 having a long axial dimension L are used, the long fiber pellets 3 are provided in the supply unit A.
2 can be bitten into the screw groove 16c without breaking, and the compression ratio CR can be easily set to a large value, so that the long fiber pellets 32 are entangled with each other and the bulk density is small (material Even when the material is supplied in a state in which the filling degree is low, it is possible to gradually increase the filling degree of the material from the supply section A to the compression section B. This improves the heat transfer characteristics of the material and makes it easier to receive heat from the outside.
It becomes possible to accelerate the melting of the long fiber pellets 32.

Next, the operation of this embodiment will be described. The long fiber pellets 32 are supplied to the hopper 14 and a motor (not shown) is rotated to rotate the screw 16. As a result, the long fiber pellets 32 are inserted into the screw groove 16c of the screw 16 through the supply port 12b of the plasticizing cylinder 12. At this time, the screw groove 16c has a groove depth dimension hf of the supply portion A thereof,
Since the length L of the long fiber pellet 32 is larger than the length L of the long fiber pellet 32, the long fiber pellet 32 is hardly damaged in the supply section A and is not damaged by the screw groove 16c.
Will fall inside. With the rotation of the screw 16, the long fiber pellets 32 are sequentially supplied to the supply section A (cross-sectional area Vf
) To the discharge portion C (cross-sectional area Vm), the cross-sectional area of the screw groove 16c is gradually reduced, so that the screw groove 16c is forcibly compressed, so that the bulk specific gravity is gradually increased, and the heat from the outside is effectively absorbed. Upon receipt, heat generated by shearing is melted and kneaded to produce a molten material containing long glass fibers. The molten material reaches the discharge portion C, and is extruded from the extrusion port 12c of the plasticizing cylinder 12 into the material storage chamber M through the check valve and the flow passage 21a arranged at the position 28 of the injection cylinder 21. As a result, the injection plunger 22 is retracted to the right in FIG. 1, and the molten material is measured. When a predetermined amount of molten material is stored in the material storage chamber M, the rotation of the screw 16 is stopped.
Then, as shown in FIG. 1, the nozzle 2 of the plasticizer 10
6 penetrates the stationary platen 34 and is pressed against the stationary side mold 38, the ram 24 is pressed leftward in the drawing, and the injection plunger 22 is forcibly moved leftward in FIG. 1 via the rod 23. As a result, the molten material in the material storage chamber M is injected into the cavity E in the state where the mold is closed but the mold is not clamped, as shown in the figure. At this time, the valve body of the check valve arranged at the position 28 is pushed in the direction of closing the extrusion port 12c by the injection pressure, so that the molten material does not flow backward from the material storage chamber M to the plasticizing cylinder 12. Absent. After the injection is completed, the movable platen 36 is driven to the right in the drawing by a mold clamping cylinder (not shown) to perform mold clamping. During the mold clamping operation, the ram 24 exerts a force to the left in the drawing. This prevents the molten material in the cavity E from flowing back into the material storage chamber M.
After molding, the mold is opened, the molded product is taken out, and the same operation as above is repeated, whereby the injection compression molded product can be repeatedly molded.

In the above description of the embodiment, it is assumed that the molds 38 and 40 inject while the molds are stopped at a predetermined halfway position of the mold closing, but the invention is not limited to this.
The injection may be performed at the mold opening position or at an appropriate timing during the mold closing operation. Although the dies 38 and 40 are of the horizontal type, the present invention can be applied to a vertical type, that is, a vertical compression molding apparatus.

[0010]

As described above, according to the present invention,
It contains long fibers such as glass long fibers, and even when using long fiber pellets whose length dimension of the pellet is considerably longer than normal one, melting, kneading, in a state in which there is little breakage of long fibers, Since there is no need to separately prepare a stampable sheet or automatically load the sheet into the compression molding machine with the shape adjusted, a molded product with excellent impact resistance can be efficiently manufactured at low cost. Can be manufactured well.

[Brief description of drawings]

FIG. 1 is a sectional view of an injection compression molding apparatus according to an embodiment of the present invention.

FIG. 2 is a diagram showing a screw embodying the present invention.

[Explanation of symbols]

 10 Screw Pre-Plastic Type Plasticizer (Plasticizer) 12 Plasticizing Cylinder 12a Cylinder Hole 12b Supply Port 12c Extrusion Port 14 Hopper 16 Screw 18 Pressurizing Cylinder 20 Plunger Type Measuring / Injecting Device (Measuring / Injecting Device) 21 Injection Cylinder 21a Flow path 22 Injection plunger 26 Nozzle 30 Mold clamping device 32 Long fiber pellet 34 Fixed plate 36 Movable plate 38 Mold (fixed side mold) 40 Mold (movable side mold) E Cavity M Material storage chamber

Claims (2)

[Claims] 1. A long fiber pellet made of a resin containing long glass fibers is supplied from a hopper to a plasticizing cylinder having a conical cylinder hole, and then a conical screw is rotated in the plasticizing cylinder. The long groove depth of the long fiber pellets bites into the screw groove formed so that the groove depth dimension on the supply side is larger than the axial length of the long fiber pellets, and the screw groove depth gradually decreases from the supply side to the discharge side. It is melted and kneaded by moving in the screw groove, then the molten material is extruded from the plasticizing cylinder into the injection cylinder by a predetermined amount and stored by retracting the injection plunger in the injection cylinder, then the injection plunger. Injecting molten material into a mold that is not completely closed by forcibly advancing, then closing and clamping the mold A method for molding a resin material containing long glass fibers, characterized in that the molten material is compression-molded into a predetermined shape according to. 2. A plasticizer (10) having a hopper (14), a plasticizing cylinder (12) integral therewith, and a screw (16) rotatably fitted thereto, an injection cylinder (21), A metering / injecting device (20) having an injection plunger (22) axially movably fitted thereto and a nozzle (26) provided at the front of the injection cylinder (21), and a mold (38 and A mold clamping device (30) provided with 40), and a molding device for a resin material containing long glass fiber, comprising: the plasticizing cylinder (12) having a cylinder hole (1
2a) is formed in the shape of a conical hole having a diameter that gradually decreases from the supply side toward the extrusion side. The screw (16) has a conical shape of the cylinder hole (12a) formed by the outer periphery of the flight part (16b). The screw groove (16c) has a conical shape corresponding to the shape, and the groove depth (hf) of the feeding portion is such that the axial dimension of the long fiber pellet (32) made of a resin containing long glass fibers ( L), the shaft portion (16a) excluding the flight portion (16b) is formed to have a constant outer diameter over the entire length, and the screw groove depth extends from the supply side to the extrusion side. The measuring / injecting device (20) is formed by a molten material extruded from the plasticizing device (10) to form an injection plunger (2).
2) is retracted to perform the measurement, and after the completion of the measurement, the injection plunger (22) is forcibly advanced so that the molten material can be injected from the nozzle (26). ) Is a state in which the molds (38 and 40) are not completely closed, the molten material is injected into the molds (38 and 40) from the measuring / injecting device (20), and the molds are closed after the injection is completed. A molding device for resin material containing long glass fibers, which is configured to perform compression molding of a molten material into a predetermined shape by performing mold clamping.