JPH0615193B2 - Extrusion molding method and apparatus for thermosetting resin - Google Patents

Description

TECHNICAL FIELD The present invention relates to a novel extrusion molding method and apparatus for thermosetting resins.

Specifically, since it has excellent flame retardancy, heat resistance, etc., a method of extrusion molding a molded product made of a thermosetting resin that is widely used in the fields of construction, electricity, electronics, etc. with high quality and with high productivity, and Regarding the device.

[Conventional technology]

As a molding method of the thermosetting resin, a compression molding method, a transfer molding method, an injection molding method and an extrusion molding method are known,
An apparatus suitable for each molding method is used.

Of these thermosetting resin molding methods, a plunger extrusion method is generally used as an extrusion molding method, and a long-shaped extruded product having a simple shape such as a round bar or a pipe is produced. However, in the plunger extrusion method,
Since the extrusion pressure in the die part is high and the extrusion is intermittent, it is difficult to obtain a uniform molded product and the productivity is low.

Under such circumstances, a molding method using a so-called screw type extrusion molding method has been developed, and for example, Japanese Patent Publication No. 46-22595 discloses an extruder used for the method.
The method using the apparatus is a molding method in which a thermosetting resin kneaded and melted in an extruder is introduced into a mold through an adapter and shaped into a final shape. However, in such a molding method, 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 occurrence of retention. Therefore, it was difficult to continuously and stably perform molding.

Further, this type of method cannot avoid a quality problem due to the presence of the spider portion supporting the mandrel or the weld portion due to the spider mark. Further, it has been difficult to adjust the extrusion pressure appropriately to the molding material and to stably manufacture a molding having uniform quality.

[Problems to be Solved by the Invention]

The object of the present invention is to solve the above problems, prevent a local curing reaction during extrusion molding, and adjust the extrusion pressure appropriately according to the molding material, whereby a molded product having a uniform quality. It is to provide a method and an apparatus for manufacturing a product with high productivity.

[Means for Solving the Problems]

The present inventors have made various studies on solving the above-mentioned problems, a cylinder having a constant inner diameter, and
Using a screw with a specific shape, by shaping the thermosetting resin in the gap between the smooth part of the screw tip and the cylinder to such an extent that the self-shape can be maintained after extrusion, uniform quality is obtained. The present invention has been accomplished by finding that a molded product having the same can be continuously shaped with good productivity.

That is, the first aspect of the present invention is a cylinder having a constant inner diameter, and all or part of the measuring portion has an inclination angle of 1/1000 to 30/1000 with respect to the screw axial direction, and Using an extruder equipped with a screw having a smooth portion at the tip, in the gap between the smooth portion of the screw and the cylinder at that portion, after shaping into a tubular shape to the extent that it can retain its self-shape after extrusion, the cylinder Phenolic resin characterized by being continuously extruded from the tip,
It is an extrusion molding method of a melamine resin, a urea resin or an epoxy resin.

Further, the second aspect of the present invention, in the extrusion molding apparatus having a temperature control mechanism in each part of the cylinder corresponding to the screw supply section, compression section and metering section, the extrusion molding apparatus, (1) constant inner diameter And (2) all or part of the measuring part is 1000 in the axial direction of the screw.
Equipped with a screw having an inclination angle of 1/30 to 1/30 and having a smooth portion at the tip, which promotes the curing reaction in the gap between the smooth portion of the screw and the cylinder at that portion, and after extrusion, This is an extrusion molding apparatus for phenol resin, melamine resin, urea resin or epoxy resin, which is shaped and cured into a tubular shape to the extent that the shape can be retained and then continuously extruded from the tip of the cylinder.

Examples of the thermosetting resin used in the present invention include phenol resin, melamine resin, urea resin, unsaturated polyester resin, epoxy resin, silicone resin, allyl resin, xylene resin, and aniline resin. Phenol resin, melamine resin, urea resin or epoxy resin is preferable, and among them, it is suitable for molding phenol resin and melamine resin.

Thus, these thermosetting resins may optionally contain fillers, mold releasing agents, and the like, which are generally used in the molding of thermosetting resins.
A thickener, a colorant, a dispersant, a foaming agent, or a polymerization initiator, a curing accelerator, a polymerization inhibitor, etc. can be added. Further, various kinds of polymers or organic or inorganic fibrous substances such as glass fibers can be added.

The feature of the present invention resides in the structure of the tip of the screw of the extruder, in particular, a screw having a smooth portion at the tip, and a screw having a specific inclination angle with respect to the axial direction in all or part of the measuring portion. The point is to use the resin to cure and shape the resin in the gap between the smooth portion and the cylinder, and then continuously extrude from the tip of the cylinder.

As an extruder to be used, not only a single-screw extruder but also a twin-screw or multi-screw extruder in which the tip end is finally integrated into a single screw can be used.

As the internal structure of these extruders that can be used in the present invention,
There is no problem in providing a deaeration hole or a special kneading structure between the feeding section of the extruder and the measuring section at the tip. There is no problem with making multiple flights or changing the pitch.

The typical screw used in the present invention is the first
As shown in the figure, it is a screw having a smooth portion 4 at its tip (hereinafter abbreviated as a special screw), and this screw comprises, for example, a supply unit 1, a compression unit 2, and a measuring unit 3. The smoothing section 4 may be of a type such that it starts from the end of the supply section as shown in FIG. 1, the end of the compression section as shown in FIG. 2 or the middle of the metering section as shown in FIG. .

Further, the screw diameter of the smooth portion 4 can be adjusted by enlarging or reducing it in accordance with the desired inner diameter of the molded product, separately from the diameter of the screw bottom portion of the portion having the flight. The inner diameter of the cylinder at the smooth portion 4 can be adjusted by enlarging or reducing it according to the outer diameter of the molded product. The inner diameter of the cylinder of the smooth part 4 can be adjusted by enlarging or reducing it according to the outer diameter of the molded product, but in order to prevent resin retention, it is the same as the inner diameter of the cylinder of other parts. It is preferable that

Therefore, all or part of the screw surface of this measuring unit is
It has an inclination angle with respect to the screw axial direction, and the inclination angle can be appropriately selected from the range of usually 1/1000 to 30/1000, preferably 1/1000 to 10/1000.

The L / D of the special screw used in the present invention is usually 7
-40, preferably 10-35, more preferably 15-
25, the compression ratio is 1.0 to 5.0, preferably 1.2 to
4.0, more preferably 1.5 to 3.0, the length of the smooth portion of the screw tip is 1D to 15D, preferably 2D to
It can be appropriately selected from the range of 10D, more preferably 2D to 7D.

With a normal full flight screw having no smooth portion at the tip, a pipe-shaped molded product cannot be obtained, but only a spiral-shaped molded product can be obtained. Further, when the length of the smooth portion is less than 1D, the molded product obtained after extrusion is deformed and it is difficult to continuously obtain a good molded product. The length of the smooth part is 1
When it is 5D or more, the molding pressure becomes large, and it is not practical in terms of the mechanical strength after extrusion.

The compression ratio of the screw and the length of the smooth part are the gap between the screw and the cylinder of the smooth part, in other words, the wall thickness of the molded product,
There are various limitations due to the combination of the extrusion rate and the characteristics of the materials used. As the compression ratio of the screw and the length of the smooth portion become larger or smaller, the back pressure applying function becomes larger or smaller.

If the back pressure is too large, excessive kneading will occur in a portion having a flight, resulting in excessive heat generation and curing of the material, which is not preferable. On the other hand, if the back pressure is too small, compression filling and kneading of the material will be insufficient, which is also not preferable. Moderate back pressure is required for compressive filling of the material and proper kneading. That is, in order to obtain stable extrusion and a good product, an appropriate screw compression ratio and smooth part length are required.

The larger or smaller the clearance between the screw and the cylinder in the smooth part, the smaller or the larger the extrusion speed, the smaller or the larger the viscosity of the material used, and the smaller or the larger the curing speed of the material used. It is necessary to increase or decrease the compression ratio of the screw and the length of the smooth portion.

By providing all or part of the screw surface of the measuring section with an inclination angle with respect to the screw axial direction, the effect of reducing the frictional resistance between the screw or cylinder and the resin in the measuring section or the compression and pressure bonding effect of the resin can be obtained. Have.

That is, for example, if the screw surface is inclined in such a direction that the screw diameter becomes smaller toward the tip, it becomes possible to reduce the frictional resistance between the screw and the resin, and as a result, excessive pressure is applied to the molten resin. It has the effect of reducing the pressure in the case where it is applied.

The tilt angle is usually 1/1000 to 30/1000.
The range is good, and if it is less than 1/1000, the effect is the same as when there is no inclination. Further, when it exceeds 30/1000, it is not necessary because the contact between the screw and the resin is limited to a short distance.

Further, for example, inclining the screw surface in the direction in which the screw diameter increases toward the tip has the effect of improving the compression and compression effect on the resin. The inclination angle may be in the range of 1/1000 to 30/1000, and 1
If it is less than 1/000, the effect is the same as when there is no inclination,
In addition, if the inclination angle exceeds 30/1000 over the entire measuring section, the compression effect becomes excessive, and as a result,
This is not preferable because the resin pressure becomes excessive. Further, when the inclination angle of a part of the weighing unit exceeds 30/1000, it is considered as a modification of the compression unit.

In carrying out the method of the present invention, the temperature of the extruder corner is set such that the characteristics of the material used, the compression ratio of the screw, the size of the gap between the screw smooth part and the cylinder, the length of the smooth part, the extrusion speed, etc. The temperature setting of the cylinder part corresponding to the compression part, the measuring part and the smooth part of the screw is usually 50 to 200 ° C., preferably 60 to
It is in the range of 150 ° C.

When the set temperature is 50 ° C or lower, it is difficult to obtain a good molded product because the curing reaction of the resin does not proceed sufficiently. On the other hand, thermosetting resins that are usually used at temperatures up to 200 ° C are not sufficient. It does not need to be heated to a higher temperature as it is heat-cured.

Further, the screw type extrusion molding apparatus of the present invention is a temperature control mechanism including a temperature detection device, a heat supply device having a predetermined heat capacity, and a cooling device, etc., in each part of the cylinder so that molding can be performed at such a set temperature. Set up. The type of the temperature control mechanism is not particularly limited and may be one used in a usual extruder for thermosetting resins.

For example, a thermocouple type thermometer is exemplified as the temperature detecting device, an electric heater (heater) having a predetermined calorific value is exemplified as the heat supplying device, and an air cooling device or a circulating device for water or the like is exemplified as the cooling device device. Is exemplified.

As a temperature control method, if the temperature of the cylinder falls below the set temperature, increase the amount of current supplied to the electric heater to enhance heating, and conversely, if it rises above the set temperature,
A method of controlling each part of the cylinder to a predetermined set temperature by reducing the amount of current, circulating a cooling medium such as water in the jacket of the cylinder, or cooling the outside of the cylinder by air is exemplified. .

In the screw-type extrusion-molding apparatus of the present invention, the curing reaction of the resin is promoted in the gap between the smooth part of the screw and the cylinder at that portion, and the curing reaction is advanced at least to the extent that the molded article after extrusion can maintain its self-shape. During this time, the final molded product or a shape close to it is formed.

The present invention will be described below with reference to the drawings.

1 to 3 are side views showing an example of a screw having a smooth portion at the tip used in the present invention.

FIG. 1 shows a screw in which the compression portion and the measuring portion of the screw are smooth portions, and shows an example in which a part of the diameter of the measuring portion has an inclination angle in a direction increasing toward the tip.

FIG. 2 shows a screw in which the entire measuring portion of the screw is a smooth portion, and shows an example in which the entire diameter of the measuring portion is provided with an inclination angle in a direction increasing toward the tip.

Fig. 3 shows that a part of the measuring part of the screw has a smooth part,
An example is shown in which a part of the diameter of the measuring portion has an inclination angle in a direction that increases toward the tip.

Fig. 4 shows that a part of the measuring part of the screw has a smooth part,
An example in which an inclination angle is provided in the direction in which the diameter decreases toward the tip over the entire measuring portion is shown.

FIG. 5 shows an example in which a part of the measuring part of the screw has a smooth part and a diameter of part of the measuring part has an inclination angle in a direction increasing toward the tip.

FIG. 6 shows an example of a preferred extrusion apparatus for carrying out the method of the present invention, including a perspective view of the screw portion. In the figure, the thermosetting resin material supplied from the hopper 7 is heated and melted by the heater 9 in the cylinder 8, and moves from the flight tip of the screw 10 to the smooth part 4 in a spiral shape, and the friction resistance with the cylinder is increased. As a result, the gap portion generated by the screw flight is narrowed and finally pressure-bonded. Next, the fusion-bonding resin is shaped to such an extent that the self-shape can be maintained after extrusion while moving through the smooth portion of the screw, and is extruded as a continuous pipe-shaped molded product 11 from the tip of the cylinder.

The temperature of each part of the cylinder corresponding to the corner parts of the supply part, compression part, metering part and smooth part of the screw 10 is measured by the thermometer 1.
The temperature of each part of the cylinder is controlled by the temperature control mechanism 13 so that the temperature of each part of the cylinder is maintained at each set temperature. When the temperature of each cylinder tends to fall below the set temperature, the current flowing through the heater of each part is increased to enhance heating. When the temperature of each cylinder tends to be higher than the set temperature, reduce the current flowing through the heater of each part. If cooling is required,
A cooling medium such as water may be passed through a jacket separately installed in the cylinder, or the cylinder may be air-cooled from the outside by using a blower or the like. The cooling device and the heater are automatically operated by the temperature adjusting mechanism 13.

As described above, according to the screw type extrusion molding method and apparatus for thermosetting resin of the present invention, a long extruded product of thermosetting resin excellent in flame retardancy and heat resistance can be easily produced with high productivity. be able to.

Hereinafter, the present invention will be described in more detail with reference to Examples. In Examples and Comparative Examples, L is the length of the cylinder, D is the inner diameter of the cylinder, and C _n is each part of the cylinder.

Example 1 A caliber provided with a water-cooling jacket in a length of 2D from the bottom of the hopper, and subsequently, a heating heater of 2 kW and a temperature control mechanism in each of 3D to 10D, 11D to 16D, 17D to 20D and 21D to 24D. 40 mmφ, L / D =
With an extruder having 24 cylinders, a feeding section 5D,
The compression part 12D, the tip following the measuring part with a diameter of the screw bottom of 35 mm. Has a smooth part with a length of 160 mm (4D), and the measuring part (including the smooth part) from the screw tip to 1
Using a screw having a compression ratio of 2.0, which has a tilt angle of 5/1000 in a direction in which the diameter decreases toward the tip of the screw over a length of 20 mm (3D), a phenol resin (Sumitomo Bakelite) is used as a molding material. Molding was performed using a trade name: PM-635J manufactured by Co., Ltd.

The temperature of each part of the cylinder is C ₁ (0 to 2D) ……………… Water cooling C ₂ (3D to 10D) ……… 60 ° C C ₃ (11D to 16D) …… 90 ° C C ₄ (17D to 20D) …… set _{110 ℃ C 5 (21D~24D) ......} 120 ℃, was extruded under the conditions of a screw rotation speed of 27 rpm.

The molding result and the result of the hydraulic test of the obtained pipe are first
Shown in the table.

Comparative Example 1 By means of an extruder with the cylinder used in Example 1,
The diameter of the supply section 5D, the compression section 12D and the screw bottom is 35
35 mm in diameter and 160 m in length at the tip part following the measuring part of mm
Molding was carried out in the same manner as in Example 1 using a screw having a compression ratio of 2.0 and having a smooth portion of m (4D).

The molding result and the result of the hydraulic test of the obtained pipe are first
Shown in the table.

Example 2 By means of the extruder with the cylinder used in Example 1,
The diameter of the supply section 5D, the compression section 12D and the screw bottom is 3
120 mm in length (3 mm
D) having a smooth portion, and in the measuring portion (including the smooth portion) at a position from 80 mm to 160 mm from the screw tip, in the direction in which the diameter increases toward the screw tip, 1000
Cutting edge 80mm (2D) with a tilt angle of 10 minutes
Was molded using a phenol resin (manufactured by Nippon Gohsei Kako Co., Ltd., trade name Nikkalite 950-J) as a molding material using a screw with a compression ratio of 1.5 that does not have an inclination angle. .

The temperature of each part of the cylinder is C ₁ (0 to 2D) ……………… Water cooling C ₂ (3D to 10D) ……… 60 ° C C ₃ (11D to 16D) …… 90 ° C C ₄ (17D to 20D) …… 110 ° C. C ₅ (21D to 24D) ... 125 ° C. was set, and extrusion was performed at a screw rotation speed of 27 rpm.

The molding result and the result of the hydraulic test of the obtained pipe are first
Shown in the table.

Comparative Example 2 By the extruder having the cylinder used in Example 1,
The diameter of the supply section 5D, the compression section 12D and the screw bottom is 35
The diameter of the tip part following the measuring part of mm is 35 mm and the length is 120 m.
Molding was performed in the same manner as in Example 2 using a screw having a compression ratio of 1.5 and having a smooth portion of m (3D).

The molding result and the result of the hydraulic test of the obtained pipe are first
Shown in the table.

As shown in Table 1, when a material with high resin pressure and difficult to mold is used, molding is facilitated by providing the screw metering section with an inclination angle in the direction in which the screw diameter decreases toward the tip of the screw. I found out that
Also, when the resin pressure becomes low and it is difficult to obtain a dense molded product, a precise molding with excellent mechanical strength can be achieved by providing the screw measuring section with an inclination angle in the direction in which the screw diameter increases toward the tip of the screw. You can see that the product is obtained.

〔The invention's effect〕

According to the present invention, a thermosetting resin such as a phenol resin can be molded in the gap between the smooth portion of the screw and the cylinder at that portion without using an adapter and a mold, so that the resin flow path is complicated. Never changes. Therefore, the local curing reaction can be prevented, and the quality of the obtained molded product becomes uniform.

Further, since a screw having an inclination angle with respect to the axial direction is used for all or part of the measuring unit, it becomes possible to appropriately adjust the friction resistance between the screw or cylinder and the resin, and the extrusion pressure can be adjusted according to the molding material. Can be increased or decreased. Therefore, the quality of the obtained molded product can be made more uniform, and a molded product having excellent mechanical strength can be obtained.

[Brief description of drawings]

1, 2, and 3 are cross-sectional views showing a part of a screw having a smooth portion at the tip used in the present invention. FIG. 1 shows an example of a screw in which the compression part and the metering part of the screw are smooth parts, and shows an example in which a part of the diameter of the metering part has an inclination angle in a direction increasing toward the tip. FIG. 2 shows an example of a screw in which the entire measuring portion of the screw is a smooth portion, and shows an example in which an inclination angle is given to the diameter of the entire measuring portion in a direction increasing toward the tip. FIG. 3 shows an example in which a part of the measuring part of the screw is provided with a smooth part, and an example in which a part of the measuring part is provided with an inclination angle in a direction increasing toward the tip. FIG. 4 shows an example in which a part of the measuring part of the screw is provided with a smooth part, and an example in which an inclination angle is provided in the direction in which the diameter becomes smaller toward the tip over the entire measuring part. FIG. 5 shows an example in which a part of the measuring part of the screw is provided with a smooth part, and an example in which the diameter of part of the measuring part is provided with an inclination angle in a direction increasing toward the tip. is there. FIG. 6 shows an example of a preferred extrusion apparatus for carrying out the method of the present invention, including a perspective view of the screw portion. 1 ... Supply section, 2 ... Compression section, 3 ... Measuring section 4 ... Smooth section, 5 ... Slope angled section, 6 ... No tilt section, 7 ... Hopper, 8 ... Cylinder, 9 ...... Heater, 10 ...... Screw, 11 ...... Molded product, 12 ...... Thermometer, 13 ...... Temperature control mechanism,

 ─────────────────────────────────────────────────── ─── Continuation of the front page Judgment panel Judge General Yasuo Hori Judge Hiroyuki Sugino Judge Akihiro Wataya (56) References Japanese Patent Publication No. )

Claims (2)

[Claims] 1. A cylinder having a constant inner diameter, and
All or part of the measuring part is 10 in the axial direction of the screw.
An extruder having a screw having a tilt angle of 1/00 to 30/1000 and a smooth portion at the tip is used, and extrusion is performed in the gap between the smooth portion of the screw and the cylinder at that portion. An extrusion molding method of a phenol resin, a melamine resin, a urea resin or an epoxy resin, which is characterized in that after being shaped into a tube to such an extent that the rear self-shape can be retained, it is continuously extruded from the tip of a cylinder. 2. An extrusion molding apparatus having a temperature control mechanism in each part of a cylinder corresponding to a screw supply section, a compression section and a metering section, wherein the extrusion molding apparatus comprises (1) a cylinder having a constant inner diameter, and ( 2) All or part of the measuring unit is 1/1000 to 1000 in the axial direction of the screw.
A screw having an inclination angle of 30/0 and a smooth portion at the tip is provided, and the curing reaction can be promoted in the gap between the smooth portion of the screw and the cylinder at that portion, and the self-shape after extrusion can be maintained. An extrusion molding device for phenol resin, melamine resin, urea resin or epoxy resin, which is shaped and cured into a tubular shape to some extent and then continuously extruded from the tip of a cylinder.