JPH07304086A - Continuous molding method and apparatus for phenolic resin hollow rod - Google Patents

Abstract

(57) [Summary] [Structure] The shaft is inserted into the through hole provided in the shaft core of the screw, the mandrel protruding into the die along the screw axis, and the cross-sectional shape from the inlet side to the outlet side is changed. The inclination of the outside of the flow path is 35 with respect to the screw axis.
Using an extrusion device with a die that is less than or equal to
The heating zone is 120 ~ 135 ℃, the temperature of the die is 15
A hollow rod-shaped body having a modified cross-section of a phenol-based resin, which shapes a phenol-based resin material to an infusible state at 0 to 180 ° C., and a continuous molding device. [Effects] According to the present invention, unlike the conventional method, there is no resin retention or local curing due to a complicated change in the resin flow path, and a phenol-based resin excellent in flame retardancy / heat resistance and dimensional accuracy. It is possible to easily and stably manufacture a rod-shaped body having a resin modified cross section with good productivity.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel extrusion molding method, extrusion molding apparatus and extruded product of a phenolic resin which is a thermosetting resin.

[0002]

2. Description of the Related Art A compression molding method, a transfer molding method, an injection molding method and an extrusion molding method are known as molding methods for thermosetting resins, and an apparatus suitable for each molding method is used. Of these thermosetting resin molding methods, a plunger extrusion molding is generally used as an extrusion molding method. For example, JP-A-48-83155, Plastics Vol. 25, No. 3, P47 shows the manufacture of long products of simple shape such as round bars and pipes.

However, in the plunger extrusion molding apparatus, it is difficult to obtain a uniform molded product and the productivity is low because the extrusion pressure in the die is high and the extrusion is intermittent. Under such circumstances, a molding method using a so-called screw type extrusion molding device is disclosed, for example, in Japanese Patent Laid-Open No. 54-23661 or Japanese Patent Laid-Open No. 49-18949. These use a molding device that extrudes the thermosetting resin kneaded and melted in the extruder from the extruder in the shortest possible time so as not to proceed with the curing reaction, guides it to the mold through an adapter etc. and shapes it into the final shape. Is the way to do it.

However, in such a molding apparatus, the resin flow path is complicatedly changed, and the thermosetting reaction rapidly progresses due to a slight difference in temperature or pressure, or the curing reaction locally proceeds due to the occurrence of retention. Therefore, it was difficult to continuously and stably perform molding. That is, for example, JP-A-5
In the method disclosed in JP-A-4-23661, the resin heated and melted in the cylinder is introduced into a mold through an adapter and shaped into a final shape. In this process, the resin flow is once squeezed by the adapter and re-expanded around the mandrel fixed by the spider, resulting in a complicated change of the resin flow path. Therefore, retention of the resin is likely to occur, causing a problem that the curing reaction locally proceeds, or a thermosetting reaction rapidly occurs due to a slight change in pressure or temperature. Further, in order to extrude the resin while overcoming the resistance due to the complicated flow passage and preventing the resin from staying, a large extrusion pressure is required and a special extrusion device is required. Further, in this type of device, it was not possible to avoid quality problems caused by the spider mark supporting the mandrel or the welded part caused thereby.

Further, as a method for solving these problems, for example, Japanese Patent Application Laid-Open No. 59-178235 proposes a method of using a screw type extruder having a smooth portion at the tip, which is used for the production of a phenolic resin pipe. Has been done. However, in this method, since the smooth portion at the tip of the screw corresponds to the inner diameter of the pipe, considering the wall thickness of the pipe, the outer diameter is 20 mm due to the mechanical strength of the screw.
Molding pipes of less than is difficult.

Further, the adapter and spider are omitted from the extrusion molding apparatus disclosed in Japanese Patent Laid-Open No. 54-23661, and it comprises a feed screw, a cylinder, a die and a mandrel, and the mandrel is formed on the extension of the screw shaft core. An extrusion molding device is disclosed in JP-A-57-128521. This device has been proposed as a pipe forming device for thermoplastic resin. In other words, this device utilizes the property that molten thermoplastic polymer molecules are oriented in that direction when they flow through a narrow passage at high speed, and by aligning the polymer molecules in different directions in the inner and outer layers of the pipe, strength balance is achieved. The present invention relates to a technique for extruding a smooth pipe. It proposes to use an extruder equipped with a torpedo type device as an extension of the feed screw to achieve the orientation in different directions. This device is proposed for a thermoplastic resin as described above.

Further, a thick product of a hollow rod having a modified cross section such as a toothed pulley cannot be injection-molded, and even if it is thick enough to be injection-molded, its axial length is 1
Only a short product of about 0 mm could be formed. In order to manufacture a rod-shaped body having a length longer than that, it is necessary to cut out irregular shapes such as gears by cutting. As described above, with the conventional thermosetting resin molding techniques, it has been impossible to easily and stably produce a hollow rod-shaped body having a highly accurate irregular cross section, for example, a toothed pulley.

[0008]

SUMMARY OF THE INVENTION To solve the above problems, it is an object of the present invention to provide a method and apparatus for molding a hollow rod having a highly accurate irregular cross section, for example, a toothed pulley. .

[0009]

DISCLOSURE OF THE INVENTION The present inventors have studied the above-mentioned apparatus based on the technique disclosed in Japanese Patent Application Laid-Open No. 59-178235 previously disclosed by one of the present inventors, and as a result, A screw comprising a compression section and a metering section, a supply section, a cylinder section having a heat supply function corresponding to the compression section and a metering section, a die having a heat supply function attached to the tip of the cylinder, and a shaft core of the screw. Insert the shaft into the through hole and let it protrude into the die on the screw axis, or use an extrusion molding device consisting of a mandrel that is firmly attached to the tip of the screw, and use a phenol resin in the die. An extrusion molding method of a phenolic resin is adopted, which advances the curing reaction of the material and shapes it to an infusible state where it can maintain its self-shape. It found Rukoto.

That is, the present invention comprises a feed screw, a cylinder, a die and a mandrel, and the mandrel is inserted into a through hole provided in the screw shaft core so as to protrude into the die on the screw axis line, and from the inlet side to the outlet side. Extrusion device comprising a flow path changing part having a flow path transition to the side cross-sectional shape of 35 degrees or less with respect to the screw axis, and a die having a flow path having a cross section equal to the outlet side of the flow path changing part The temperature of the heating zone of the cylinder in front of the die inlet is set to 120 to 135 ° C., and the temperature of the die part is set to 150 to 180 ° C. to shape the phenolic resin material to an infusible state. A method for continuously molding a hollow rod-shaped body having a modified cross section made of a phenolic resin, which is a feature.

Still another object of the present invention is to provide a screw consisting of a supply part, a compression part and a metering part, a cylinder part having a heat supply function corresponding to the supply part, the compression part and the metering part, and a tip of the cylinder. It consists of a die with a heat supply function installed and a mandrel that is inserted into the through hole provided in the shaft core of the screw and protrudes into the die on the screw axis, or is firmly attached to the tip of the screw. The phenol resin extrusion molding apparatus is characterized in that the inclination of the outer side of the flow path that transitions from the inlet side to the outlet side of the die is 35 degrees or less with respect to the axis of the screw.

Still another object of the present invention is to include a feed screw, a cylinder, a die and a mandrel, wherein the mandrel is inserted into a through hole provided in the screw shaft core, and the mandrel is projected into the die on the screw axis. , The temperature of the cylinder heating zone in front of the die entrance is 120 ~
The temperature of the die is 150-180.
It is a hollow rod-shaped body having a modified cross section of a phenolic resin obtained by shaping a phenolic resin material to an infusible state at 0 ° C.

The extruder used in the method of the present invention is not only a single-screw extruder but also a twin-screw or multi-screw extruder, the tip of which is finally integrated into a single screw. Any of the extrusion equipment can be used. As the internal structure of these extruders used in the present invention,
There is no problem in providing a deaeration hole or a special kneading structure between the supply section of the extruder and the measuring section at the tip. Further, a device having a cross section that is slightly smaller than the die outlet may be attached to the tip of the die so that the back pressure applied to the resin can be adjusted. Further, the screw is usually a screw used for extrusion molding of synthetic resin, and may be a full flight type having a flight to the tip, or a torpedo type having a smooth portion at the tip of the screw, and the shape of the tip may be cylindrical. It may be conical.

The extrusion molding method of the phenolic resin material will be described with reference to FIG. In FIG. 1, the phenolic resin material supplied from the hopper 1 is heated and melted by the heater 3 in the cylinder 2, and is sent forward by the rotation of the screw 4 and introduced into the die 6 in a molten state. The material at the inlet of the die has a temperature in the heating zone of the cylinder in front of the inlet of the die of 120 to 135 ° C., preferably 12
By setting the temperature to 5 to 130 ° C., a uniform molten state suitable for changing the flow path is obtained. If the heating temperature is lower than 120 ° C., there is a fear that the material is uniformly melted, and if the heating temperature is higher than 135 ° C., partial curing of the material may occur, and it may be difficult to smoothly change the flow path of the material. Next, the material is extruded into a shaped product which is heated to 150 to 180 ° C., preferably 150 to 170 ° C. in the die part to accelerate the curing, and is shaped to an infusible state after extrusion.

The heating temperature in the die part is appropriately controlled by the combination of the wall thickness of the hollow rod and the extrusion rate, but if it is lower than 150 ° C., the curing reaction does not proceed sufficiently and the phenolic resin is Since it cures sufficiently at temperatures up to 200 ° C, it is not necessary to heat it further. The resin flow path in the die has a structure that changes smoothly during this period. Furthermore, the inclination of the flow path changing portion 5 that transitions from the inlet side to the outlet side of the die is 3 with respect to the axial direction.
It is 5 degrees or less, preferably 30 degrees or less. If the temperature exceeds 35 degrees, the flow path is changed rapidly, and the resin cannot flow smoothly. Further, as for the mandrel 7 in the die, for example, as shown in FIG. 2, the shaft is inserted into a through hole 8 provided in the shaft core of the screw so that the screw axis is projected into the die. The spider that supports the mandrel used in the die is unnecessary, and there is no obstacle to the flow path of the molten resin.

The resin introduced into the die moves along a smoothly changing flow path in a molten state, and is shaped and extruded into a die in a flow path having a cross section equal to the cross section of the exit to reach the die exit. It Here, the length of the flow path having a cross section equal to the exit cross section needs to be changed depending on the combination of the wall thickness, the viscosity of the material used, the characteristics such as the curing rate, and other molding conditions. ~ 15D (where D is the inner diameter of the die), preferably 2D ~ 1
It can be appropriately selected from 3D, and more preferably from 3D to 10D. If the length of this flow path is less than 1D, it tends to be difficult to sufficiently cure and a good molded product tends to be difficult to obtain, and if it exceeds 15D, the back pressure tends to be too large and extrusion tends to be difficult. is there.

In the method of the present invention, after the screw tip of the extruder, there is almost no rapid change in the resin flow path, so there is no resin retention, and there is no local curing reaction or rapid curing reaction due to pressure or temperature changes. Will not cause. The product extruded by the method of the present invention can be sufficiently shape-cured by controlling the molding conditions to such an extent that the product already retains its self-shape at the time of extrusion and is not easily deformed by external force. Therefore, when used, it does not cause warping, bending, or swelling. However, there is no problem in further post-curing treatment if necessary. in this case,
The heat distortion temperature can be improved, for example 200 ℃
It can be made suitable for use at high temperatures as described above.

If necessary, the phenolic resin material used in the present invention may be a filler, a mold release agent, a thickener, a lubricant, a colorant, a dispersant, which is commonly used in molding phenolic resins. A foaming agent, a curing accelerator, etc. can be added. Further, other kinds of polymers or organic or inorganic fibrous substances such as glass can be added. Regarding the fluidity of the phenolic resin material used in the present invention, the outflow amount is preferably in the range of 0.05 to 15 g in the JIS K6911 extrusion type flow test. However, test mold temperature 140 ° C, extrusion pressure 150 kg / cm
^Depends on condition ² . If the outflow amount is less than 0.05, uniform melting tends to be impaired in the cylinder portion, and if it exceeds 15 g, melting tends to be easy but curing at the die portion tends to be slow, which is not preferable. . The hollow rod-shaped body having a modified cross section in the present invention has a modified cross section such as a gear, and specific examples thereof include a toothed pulley. Further, the hollow rod-shaped body according to the present invention is excellent in smoothness, and a device using the hollow rod-shaped body can reduce noise.

[0019]

【Example】

[Example 1] An extruder having a diameter of 30 mm and L / D = 12 was used to supply a feeding section 7D, a compressing section 1D, a measuring section 4D, and a compression ratio of 1.
The outer diameter of the full flight screw of 5 is 5 mm
Insert the mandrel of, and the pitch diameter 1 at the tip of the cylinder.
Extrusion molding was carried out by mounting a die having a tip diameter of 9.26 mm, an outer diameter of 18.75 mm, a number of teeth of 30, a length of 100 mm, and a flow path changing portion having an inclination angle of 15 degrees. Regarding the flow characteristics of the phenolic resin material used, the outflow amount in the JISK 6911 extrusion type flow test was 2.8 g (however, the test mold temperature 1
The conditions are 40 ° C. and an extrusion pressure of 150 kgf / cm ² .
Hereinafter referred to simply as the outflow). The temperature of each part of the device is C1 (0D to 2D) ... water cooling C2 (3D to 6D) ... 80 ° C. C3 (7D to 10D) ... 105 ° C. C4 (11D to 12D) ... 130 ° C. Dice ... ........................ It was set at 155 ° C. and extrusion was performed at a screw rotation speed of 10 rpm. A toothed hollow rod having an outer diameter of the tip of 18.59 mm and good smoothness was stably and continuously extruded. It was possible to manufacture a toothed pulley by cutting it to an appropriate length.

[Embodiment 2] Embodiment 1 except that the pitch diameter is 16.37 mm, the tooth tip outer diameter is 14.42 mm, the number of teeth is 34, the length is 100 mm, and the dice having a flow path changing portion with an inclination angle of 25 degrees is changed.
Extrusion was performed in exactly the same manner as in. Outer diameter of tooth tip 15.59m
m, the toothed hollow rod having good smoothness was continuously and stably extruded. It was possible to manufacture a toothed pulley by cutting it to an appropriate length.

Example 3 A phenolic resin material having an outflow amount of 0.5 g in a flow test was used, and the mandrel had an outer diameter of 8 mm, a pitch diameter of 21.58 mm, and a tooth tip outer diameter of 2
Example 1 except that the die having 1.03 mm, the number of teeth of 45, and the length of 200 mm and the screw rotation speed were changed to 15 rpm.
Extrusion was performed in exactly the same manner as in. Outer diameter of tooth tip 20.85m
m, the toothed hollow rod having good smoothness was continuously and stably extruded. It was possible to manufacture a toothed pulley by cutting it to an appropriate length.

[Embodiment 4] The outflow amount is 4 in the flow test.
g of phenolic resin material, caliber 50mm,
L / D = 12 extruder, supply unit 7D, compression unit 1
D, metering section 4D, a mandrel with an outer diameter of 10 mm is inserted into the axis of a full flight type screw with a compression ratio of 1.5,
Extrusion molding was carried out by mounting a die having a pitch diameter of 32.10 mm, an outer diameter of a tooth tip of 31.59 mm, a number of teeth of 50, a length of 200 mm, and an inclination angle of 15 degrees of a flow path changing portion at the tip of the cylinder. The temperature of each part of the device is C1 (0D to 2D) ... water cooling C2 (3D to 5D) ... 80 ° C. C3 (6D to 8D) ... 95 ° C. C4 (9D to 10D) ... 100 ° C. C5 (11D) ~ 12D) ... 130 ° C. Die: The temperature was set to 165 ° C., and extrusion was performed at a screw rotation speed of 10 rpm. A toothed hollow rod having an outer diameter of the tip of 31.32 mm and good smoothness was stably and continuously extruded. It was possible to manufacture a toothed pulley by cutting it to an appropriate length.

[Embodiment 5] The outflow rate in the flow test is 1
0 g of phenolic resin material is used, and the pitch diameter is 38.
53 mm, tip outer diameter 38.01 mm, number of teeth 60, length 4
Extrusion was performed in exactly the same manner as in Example 4 except that the die was changed to 00 mm. A toothed hollow rod having an outer diameter of the tip of 37.69 mm and good smoothness was stably and continuously extruded. It was possible to manufacture a toothed pulley by cutting it to an appropriate length.

[Comparative Example 1] Extrusion was carried out in the same manner as in Example 1 except that a phenolic resin material having an outflow amount of 4 g was used, the temperature of the cylinder C3 was 115 ° C, and the temperature of the die was 135 ° C. I tried. After the start of extrusion, the extrusion load gradually increased, and after about 10 minutes, molding could not be performed.

Comparative Example 2 Extrusion molding was tried in the same manner as in Example 2 except that the inclination angle of the flow path changing portion was changed to 40 degrees.
The extrusion load was not stable and it became impossible to obtain a molded product of uniform quality.

[0026]

EFFECTS OF THE INVENTION According to the present invention, unlike the conventional method, there is no resin stagnation or local curing due to complicated changes in the resin flow path, flame retardancy, heat resistance, smoothness and dimensional accuracy. It is possible to easily and stably produce a toothed hollow rod-shaped body of a phenolic resin excellent in productivity with high productivity.

[Brief description of drawings]

FIG. 1 is one of the preferred devices used in the method of the present invention.
Example.

[FIG. 2] 1 of attachment method of detachable mandrel
Example.

[Explanation of symbols]

 1 Hopper 2 Cylinder 3 Heater 4 Screw 5 Flow path changing part 6 Die 7 Mandrel 8 Through hole

Continuation of front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display area // B29K 61:04 B29L 15:00 23:00

Claims (9)

[Claims] 1. A cross section from an inlet side to an outlet side, which comprises a supply screw, a cylinder, a die and a mandrel, and the mandrel is inserted into a through hole provided in a screw shaft core and protrudes into the die on the screw axis. Using an extrusion molding device composed of a die having a flow passage changing part in which the inclination of the flow passage changing to a shape is 35 degrees or less with respect to the axis of the screw and a flow passage having a cross section equal to the outlet side of the flow passage changing part. The temperature of the heating zone of the cylinder just before the entrance of the die is set to 120 to 135 ° C, and the temperature of the die is set to 15
A continuous molding method of a hollow rod-shaped body having a modified cross section made of a phenolic resin, which comprises shaping the phenolic resin material to 0 to 180 ° C. to an infusible state. 2. The method for continuously molding a rod-shaped body according to claim 1, wherein the modified cross section has a gear shape. 3. Phenolic resin material JIS K69
11 Extrusion type flow rate is 0.05 to 15g
The extrusion molding method according to claim 1 or 2. 4. The extrusion molding method according to claim 1, wherein the temperature of the heating zone of the cylinder before the die inlet is 125 to 130 ° C., and the temperature of the die part is 150 to 170 ° C. 5. The extrusion molding method according to claim 1 or 2, wherein the inclination of the portion that transitions from the inlet side to the outlet side of the die is 35 degrees or less with respect to the axial direction. 6. The length of the flow passage having the same cross section as the outlet side of the flow passage changing portion is 1D to 15D, where D is the inner diameter of the die.
The extrusion molding method according to claim 1 or 2, wherein 7. The length of a flow path having a cross section equal to the cross section of the exit of the die is 2D to 1 where D is the inner diameter of the die.
The extrusion molding method according to claim 6, which is in a range of 3D. 8. A screw having a supply part, a compression part, and a metering part, a cylinder part having a heat supply function corresponding to the supply part, the compression part, and the metering part, and a heat supply function attached to the tip of the cylinder. The shaft is inserted into the through hole provided in the axis of the die and screw, and consists of a mandrel that protrudes into the die on the screw axis. A continuous molding device for a rod-shaped body having a hollow irregular cross section made of a phenolic resin, characterized in that the outer inclination is 35 degrees or less with respect to the axis of the screw. 9. A feed screw, a cylinder, a die, and a mandrel, wherein the mandrel is inserted into a through hole provided in the screw shaft core and protrudes into the die on the screw axis line, and the die side from the inlet side to the outlet side. Using an extrusion molding device in which the inclination of the outer side of the flow path that transitions to the cross-sectional shape of is not more than 35 degrees with respect to the axis of the screw, the temperature of the heating zone of the cylinder in front of the die inlet is 120
The temperature of the die is 150-180.
A hollow rod-shaped body having a modified cross section made of a phenolic resin obtained by shaping a phenolic resin material to an infusible state at 0 ° C.