JPS59209839A - Apparatus for extruding hollow article - Google Patents

Abstract

PURPOSE:To make it possible to extrude a hollow article at a high speed stably that is excellent in dimensional stability and uniform in quality, by connecting coaxially a cylinder and a die vertically, and arranging heating means in a mandrel such that the position of the heating means is opposed to the tapered surface section of the inlet of the die. CONSTITUTION:A thermosetting resin 48 is fed into a cylinder 18, and is compressed by the pressing action of a plunger 28 by the actuation of a hydraulic cylinder 30 to be fed into a die 16. In this case, the die 16 transfers the heat from a heating apparatus 14 positioned outside thereof to the resin material 48, and also resin material 48 that is compressed in a compressing zone at the inlet section of the die 16 having a tapered surface 22 is given heat effectively from the inside by a heating apparatus 44 in a mandrel 40, so that the resin material 48 is effectively melted and fluidized.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a continuous extrusion molding apparatus for hollow products using a thermosetting resin as a molding material.

Conventionally, in a plunger-type extrusion molding device for thermosetting resin, molding material powder supplied from a hopper is extruded by a plunger into a die that is externally heated by a heating device, and the hardened resin is extruded into chrome, 7-metal, or It is extruded by the pressure that overcomes the frictional resistance between the inner surface of the nickel-plated die and the resin. In these devices, the molded powder material supplied from the hopper to the cylinder is moved by the plunger to the cross-sectional area of the plunger. Since the plunger is fed into the die with an internal cross-sectional area that is approximately the same as that of This caused problems such as the amount of material supplied becoming unstable and the continuous piston movement of the plunger being obstructed.

For this reason, in Japanese Patent Publication No. 52-17057,
In order to solve this problem, we have developed a cylinder in which a thermosetting resin material is extruded using a plunger, and a cylinder that is connected to the tip of the cylinder, has an internal cross-sectional area smaller than the cross-sectional area of the plunger, and has an inlet portion. and a heating die for giving a predetermined product outer shape with a tapered surface, the resin material is heated by the extrusion action of the plunger.

An apparatus has been disclosed for continuously extruding a predetermined product from the die while it is being cured. By adopting this structure, the molding material is not only compressed and hardened only in the axial direction of the conventional cylinder, but also the cross section suddenly becomes smaller after exiting the cylinder and at the entrance to the die. As a result, the charge pushed by the plunger is compressed in the radial direction, thus creating a shearing action that separates the molding material stuck to the tip of the plunger and prevents the supply of said molding material from being interrupted. This made it possible to effectively solve the stability problem.

However, even with an apparatus having a bending structure, there are still some problems that remain to be solved when extruding hollow products. That is, such a device
Generally, a die and a cylinder are connected horizontally to adopt a horizontal device configuration, and a mandrel or the like for forming a hollow product extending from the side of the cylinder to be bent into the die is arranged concentrically. The mandrel has a structure in which the extrusion molding operation of a predetermined thermosetting resin powder can proceed, but such a mandrel cannot be supported at both ends, and has a cantilever structure that is simply supported at the end on the cylinder side. Due to the structure, it is very difficult to center such a mandrel horizontally and concentrically with the die, and this causes the inherent problem of uneven thickness of the product due to the eccentric arrangement of the mandrel. That's what I'm doing.

In addition, the hollow product extruded from the die is pulled out horizontally, but gravity acts on such horizontal parts, and this tendency exists even if the extruded product is supported by guide rollers in front of the die. However, this was one of the causes of deteriorating the dimensional accuracy of the product.

Furthermore, in an apparatus having such a structure, since the resin material is simply melted by heating from the outside of the die, an uneven flow of molten resin occurs between the mandrel side and the inner side of the die. This caused uneven curing on the inner and outer surfaces of molded hollow products, and the fluidity of the molten resin was also poor, making it difficult to produce hollow products of uniform quality at high speed and stably. It was difficult.

The present invention was developed against the background of the above circumstances, and its purpose is to produce hollow products of uniform quality and excellent dimensional stability at high speed and in a stable manner. An object of the present invention is to provide an apparatus capable of extrusion molding.

In order to achieve such an object, the present invention provides a cylinder configured to extrude a thermosetting resin material using a plunger, and a cylinder that is connected to the lower end of the cylinder and has an inner cross-sectional area smaller than the cross-sectional area of the plunger. and a die with a heating means for giving a predetermined product external shape, which has a tapered surface formed at the inlet part, are coaxially connected and arranged so that their axes are substantially perpendicular, and , a mandrel extending concentrically from the cylinder into the die;
In this apparatus, a predetermined hollow product is continuously extruded through a gap between the die and the mandrel while heating and curing the resin material by the extrusion action of the plunger. In addition to providing two heating means, the second heating means is arranged so as to be located at least in a portion corresponding to the tapered surface forming portion of the die entrance portion.

As described above, according to the present invention, the extrusion device has a vertical structure in which the cylinder and the die are arranged in a substantially vertical direction, and the second heating means is provided in the mandrel, and the heating means around the die is heated. They work together to heat the resin material, and as a result, the resin material pushed from the cylinder into the die is heated from the outside as well as from the inside, so it is heated from the inside. The supply was uniform inside and outside, making it easy to melt and fluidize the resin material (η), and also make the flow of the molten resin laminar (relative flow). This effectively suppresses the occurrence of uneven curing on the inner and outer surfaces of the product, making it possible to extrude a homogeneous hollow product at high speed, and also because the product can be ejected from the die in a downward direction. It is easy to achieve straightness, and problems such as uneven thickness and curvature of the product caused by the action of gravity or eccentricity of the mandrel can be effectively suppressed, and dimensional accuracy can be improved.

Hereinafter, in order to clarify the present invention more specifically, embodiments of the present invention will be described in detail based on the drawings.

First, in FIG. 1 showing an embodiment of the present invention, a base 1
A heating device 14 is installed on the lower press plate 12 attached to the
A die (die cone) 16 is arranged so as to have a substantially vertical axis, and a cylinder 18 is arranged concentrically above the die 16, and its flange portion is tightened with bolts 20. Thus, it is connected to the die 16. The inner cross-sectional area (inner diameter) of the cylinder 18 is larger than the inner cross-sectional area (inner diameter) of the die 16.
A tapered surface 22 is formed at the die inlet that connects to the molding cylinder 18, and the diameter changes smoothly from the inner diameter of the molding cylinder 18 to the smaller inner diameter of the die 16. Sru.

Further, the cylinder 18 is provided with a fluid chamber 24 in the circumferential direction inside the wall thereof, and a predetermined temperature regulating fluid is supplied through the temperature regulating pipes 2 and f6 and circulates within the fluid chamber 24.

By being allowed to flow, the resin material supplied into the cylinder 18 can be cooled or preheated.

A plunger 28 is fitted into the cylinder 18 so as to be slidable in the vertical direction, and the upper end of the plunger 28 is attached to a plunger mounting board of a mounting frame 32 that is moved vertically by a hydraulic cylinder 30. It is attached to 34. The vertical movement of the plunger mounting plate 34, in other words, the mounting frame 32, is performed by the post 3 installed between the lower press plate 12 and the upper press plate 36.
It is designed to be guided by a guide member 39 that slides at 8.

Further, the mandrel 40 is attached to and hangs down from a support frame 42 whose upper end is fixed to the press upper plate 36 fixed to the upper part of the post 38, and the plunger mounting plate 34 and the plunger 2B are arranged concentrically. and extends into the mold. That is, the mandrel 40 extends concentrically from the cylinder 18 into the die 16, and further extends a predetermined length through the exit of the die 16.
It extends forward.

Further, the mandrel 40 has a hollow structure,
A heating device (second) 44 is provided at a predetermined position inside the mandrel.
0 includes a portion corresponding to the tapered surface 22 formed at the entrance of the die 16, and is arranged with a predetermined length so as to extend from the tapered surface 22 toward the die exit side, and is configured to receive power from the external power source 46. By heating the mandrel 40 from within, the amount of heat can be supplied from the inside to the resin material that is compressed and melted at the inlet of the die 16.

A thermosetting resin (usually used in the form of pellets) 48 as a molding material is placed in the cylinder 18.
Two material input devices 50 are arranged facing each other above the cylinder 18 to supply, for example, phenolic resin, melamine resin, urea resin, epoxy resin, diallyl fucrate resin, etc. This material input device 50 has a hopper 52, a supply cylinder 54, and a piston 56,
The thermosetting resin 48 in the supply 1M54 dropped and supplied from the hopper 52 is pushed out of the cylinder 1 by the extrusion action of the piston 56 that slides back and forth within the supply cylinder 54.
The material is fed into the cylinder 18 through an inlet 58 at the top of the material feeder 8 (which is formed oppositely around the cylinder I8 in correspondence with the material feeder 50).

The hollow product 60, which is formed by being melted and hardened between the die 16 and the mandrel 40, and is pulled out downward from the outlet located at the lower part of the die 16, is cut to a predetermined length by a cutter or the like (not shown). It is cut into pieces and taken out by a taking out device 62.

Therefore, in the extrusion device having such a configuration, a predetermined thermosetting resin 48 is supplied into the cylinder 18 from the material input device 50, and is extruded by the extrusion action of the plunger 28 operated by the hydraulic cylinder 30. The resin material 48 is compressed and fed into the die 16, and at this time, the die 16 transfers the heat from the outer heating device 14 provided on the outer periphery to the resin material 4B.
The 4IA fat material is compressed in the compression zone at the inlet of the die 16 by an inner heating device 44 disposed within the mandrel 4o corresponding to the tapered surface 22 forming portion at the inlet of the die 16. 48 may be subjected to effective heating from the inside, thereby effectively melting, fluidizing, and hardening the darning resin material 48 as it travels through the die 16. As a result, a predetermined hollow product 60 is extruded from the gap between the die 16 and the mandrel 4o.

According to such a configuration, the resin material 48 compressed at the inlet of the die 1G is heated from the outside by the heating device 14 provided on the die 16, and from the inside by the inside of the mandrel 40. Heating device (second) installed in
44, the resin material 48 located inside the mandrel 40 is effectively melted and fluidized by heating, thereby making the flow of the molten resin into a laminar flow as shown in FIG. (relative flow between the inside and outside), and can effectively eliminate curing unevenness on the inside and outside surfaces of the hollow product 60 obtained.
This made it possible to mold homogeneous hollow products.

In addition, FIG. 3 shows the resin surface temperature of 16 dies and the mandrel when extrusion was performed in the case (A) where the heating device 44 was provided in the mandrel 40 and the case (B) in which it was not provided. The results show the resin surface temperature on the ridge-to-mandrel 40 side, and when the heating device 44 is installed inside the mandrel 40, the resin temperature on the ridge-to-mandrel 40 side is significantly raised (see solid line A), which causes melting. The fluidity of the resin has been effectively increased, and therefore high-speed molding has become possible. Incidentally, according to experiments conducted by the present inventor, when the heating device 44 is not provided in the mandrel 40, the extrusion molding speed is at most about 2.0 to 2.5 m/Hr, whereas the heating device 44 5.0 to 7.0 m/
Extrusion speeds of Hr could be achieved. In addition, when performing such high-speed molding, in order to improve the dimensional accuracy of the hollow product 60 obtained, the die 1 is
It is recommended to increase the axial length of No. 6 to provide a dimensional stability range compatible with high speeds.

Further, according to such a configuration, the mandrel 40 is not arranged in a horizontal cantilever structure as in the past, but only needs to be hung down, so that the mandrel 40
The concentricity between the die 16 and the die 16 is maintained well, so that the hardened hollow product 60 extruded from between the die 16 and the mandrel 40 will not have uneven thickness, and furthermore, the hollow product 60 to be formed will not have uneven thickness. Since the product 60 naturally comes out downward from the die 16 and is taken up by a take-up roller or the like, gravity that causes bending does not act on the hollow product 60, thereby effectively maintaining its straightness. It became possible to release it. Incidentally, the hollow product obtained by the apparatus according to the present invention has a roundness of 0.
02. Cylindricity is 0.05° Straightness is 0.05mm150
The result is 0R.

Note that in this exemplary device, the thermosetting resin 48 is supplied into the cylinder 18 using two material input devices 50 provided around the cylinder 18 at an equal distance apart.
．． 50, there is an advantage that the resin material 48 can be charged more evenly around the mandrel 40 in the cylinder 18, and moreover, during such charging, the resin material 48 is prevented from falling by the mandrel 40. There is nothing that can be prevented.

The resin material 48 thus charged and evenly accumulated in the cylinder 18 from below is evenly pushed into the die 16 by the extrusion action of the plunger 28.

Next, another embodiment of the present invention will be described based on FIG. 4, in which the same parts as in the previous example are given the same numbers and detailed explanation will be omitted.

The device shown in FIG. 4 differs significantly from the previous example in the shape of the mandrel 66. That is, in the mandrel 66, at a position corresponding to the tapered surface 22 forming portion at the inlet of the die 16, a portion transitioning from the small diameter portion of the cylinder 18 example to the large diameter portion on the die 16 side is different from the tapered surface 22 of the die 16. Reverse tapered surface 6
8, and a heating device (second) 44 is disposed within the mandrel 66 corresponding to the position where the tapered surface 68 is formed.

According to the structure of the mandrel 66 of this embodiment, the resin material 48 pushed in by the plunger 28 is inserted into the die 16.
is compressed from the outside by the tapered surface 22 at the inlet of the mandrel 66, and is also compressed from the inside by the tapered surface 68 provided on the mandrel 66, and at the same time, the heating device 14 on the outside and the inside The molten resin is melted and fluidized by the heating action from the heating device 44, but by forming the tapered surface 68 on the inside in this way, the flow of the molten resin along the mandrel 66 is effectively delayed. In other words, the flow unevenness on the resin surface can be effectively improved.
As a result, uniform curing can be performed, making it possible to obtain hollow products of even better quality.

In the devices of these embodiments, the inner CV heating device 44 is disposed within the mandrel 40 or 66 at a portion corresponding to the portion where the tapered surface 22 is formed at the entrance portion of the die 16; Dice 1
It is also possible to extend a predetermined length from the inlet portion of the resin material 48 toward the outlet portion of the resin material 48 to more effectively perform the melting, curing, and molding operations of the resin material 48. Also, as the heating device 44,
Although it is most common to insert an electrical heating device into the mandrel, as illustrated, heating means of other constructions may be used instead.

Furthermore, the material charging device 50 provided around the cylinder 18 may be provided in one or more than two pieces as in the above example; 50 are arranged around the cylinder 18 at equal intervals, the predetermined resin material 48
There is an advantage that the material can be evenly charged into the cylinder 18, and furthermore, as the structure of the material charging device 50, it is possible to adopt various material charging structures in addition to the above example.

In addition, the present invention includes, based on the knowledge of those skilled in the art,
Various modifications may be made without departing from the spirit of the present invention.
It goes without saying that changes, improvements, etc. can be made, and that the present invention includes such forms within its scope.

[Brief explanation of drawings]

FIG. 1 is a front sectional view showing an example of the apparatus according to the present invention, FIG. 2 is an enlarged sectional view of the main part illustrating the flow of resin material in such an apparatus, and FIG. It is a graph showing the temperature on the die side and the mandrel side of the resin material to be extruded, and FIG. 4 is a front main part sectional view showing another example of the apparatus according to the present invention. 12 Nibbles lower plate 14: Heating device 16: Die 18 Niji cylinder 22: Tapered surface 28: Plunging middle 30: Hydraulic cylinder 36: Press upper plate 40: Mandrel 44: Heating device 48: Thermosetting resin 50: Material feeding device 52: Honova 54: Supply cylinder 56: Piston 58: Inlet 60: Hollow product 62: Take-out device 66: Mandrel 68: Tapered surface Applicant: Tokai Rubber Industries Co., Ltd. No. 2! ',,'U 60 Figure 3

Claims (1)

[Claims] (11) A cylinder configured to extrude a thermosetting resin material using a plunger, connected to the lower end of the cylinder,
A die with heating means that has an internal cross-sectional area smaller than the cross-sectional area of the plunger and has a tapered surface formed at the inlet portion and gives a predetermined product external shape, so that the axes of the die are in a substantially vertical direction. A mandrel is provided that is coaxially connected and arranged and extends concentrically from the cylinder into the die, and the extrusion action of the plunger heats and hardens the resin material while passing through the gap between the die and the mandrel. The apparatus is configured to continuously extrude a predetermined hollow product, and a predetermined second heating means is provided within the mandrel, and the second heating means is connected to the tapered surface forming portion of the die inlet. 1. An extrusion molding device for hollow products, characterized in that the extrusion molding device is arranged so as to be located at least in a portion corresponding to the above. (2) A portion of the mandrel located within the die has a larger diameter than a portion located within the cylinder, and a portion of the mandrel corresponding to the tapered surface forming portion of the die entrance has a smaller diameter on the cylinder side. 2. The device according to claim 1, wherein a tapered surface is formed to connect the large diameter portion on the die side. (3) A plurality of material charging means are provided around the cylinder, and the resin material is charged into the cylinder through the plurality of material charging means.
2. The device according to item 2 or item 2.