JPS6155152A - Thermosetting resin molding material - Google Patents

Abstract

PURPOSE:To provide the titled molding material which has excellent extrudability and gives continuously and stably moldings having excellent surface smoothness, high-temperature rigidity and mechanical strength, by blending a hardener, etc. in such a proportion to give a specified effluent rate in an extrusion flow test. CONSTITUTION:8-20pts.wt. hardener such as hexamine, 100-400pts.wt. filler such as glass fiber, 0.5-2.0pts.wt. lubricant such as stearic acid (salt), 0.2- 2.0pts.wt. plasticizer and 10-20pts.wt. flame retarder such as Sb2O3 are blended with 100pts.wt. thermosetting resin such as novolak phenolic resin in such a proportion as to give an effluent rate of 1-42g in an extrusion flow test (JIS K6911), thus obtaining the titled molding material. The material is fed to an extruder having a screw which is composed of a feed zone 1, a compression zone 2 and a metering zone 3 in which a smooth zone 4 is formed from the end of the feed zone 1 and which has an adjusted diameter enlarged or reduced according to the outer and inner diameters of the desired molding in an L/D ratio of 7-40. The material is extruded at 50-200 deg.C and shaped during the passing thereof through the smooth zone 4 to such an extent that its shape can be self-retained after extrusion, thus obtaining the desired molding.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention is a novel extrusion molding method for thermosetting resins with excellent flame retardancy and heat resistance, which are in strong market demand in the fields of architecture, electricity, electronics, etc. Regarding materials.

[Conventional technology]

Compression molding, transfer molding, injection molding, and extrusion molding are known as methods for molding thermosetting resins, and molding materials suitable for each molding method are used.

Among these methods for molding thermosetting resins, two extrusion methods have been developed: a plunger extrusion method and a screw bottle extrusion method.

[Problem that the invention seeks to solve]

Plunger extrusion is used to produce long extruded products with simple shapes such as round bars and pipes. However, in the plunger extrusion molding apparatus, the extrusion pressure in the mold section is high, and furthermore, because of intermittent extrusion, it is difficult to obtain uniform molded products and the productivity is low.

Under these circumstances, a molding method using a so-called screw extrusion molding device has been developed. This is a molding device that guides thermosetting resin molding material kneaded and melted in an extruder into a mold through an adapter and shapes it into a final shape. However, with conventional thermosetting resin molding materials, the extrusion pressure in the mold section is high, and moreover, because of intermittent extrusion, uniform molded products cannot be produced. In addition, in such molding equipment, the flow path of the molding material changes in a complicated manner, and the curing reaction of the thermosetting resin may proceed rapidly due to a slight difference in temperature or pressure, or the curing reaction may occur locally due to stagnation. No thermosetting resin molding material has been found that can undergo stable molding over a long period of time.

The present inventors have previously provided a new molding method that solves the problems of conventional extrusion and extrusion molding methods. (Special application 1986-1048
91) As for the molding method, for example, a thermosetting resin extrusion molding method is adopted in which a screw having a smooth portion at the tip is used and the smooth portion is shaped to the extent that it can maintain its own shape after extrusion. However, even in this case, conventional thermosetting resin molding materials have poor moldability and are difficult to continuously and stably mold.

Means for Solving Problem C] As a result of various studies on solving the above-mentioned problems of thermosetting resin molding materials, the present inventors have developed a method for extrusion molding of thermosetting resin. We found that controlling the overall flowability is particularly important due to the large amounts of other additives to the thermosetting resin material, and we further conducted an extrusion flow test (JI
The inventors have discovered that a thermosetting resin molding material having a flow rate within a specific range (SK6911) can solve these problems, and have arrived at the present invention.

That is, the present invention uses a screw having a smooth portion at its tip and shapes the material to the extent that it can maintain its own shape after extrusion in the smooth portion, or has a die inlet portion formed from a cylindrical portion of an extruder. This is a molding material for which a die is attached close to the tip of the screw and is shaped within the die to the extent that it can maintain its own shape after extrusion, and the outflow amount in the extrusion flow test (JISK6911) is 1.
g~429 thermosetting resin molding material suitable for continuous extrusion molding (however, the measurement conditions for the extrusion flow test are
5g, temperature 140°C, pressure 150kg/c-).

The extrusion type flow of the thermosetting extrusion molding material in the present invention is 1
-429 can be achieved by considering combinations of types and amounts of resins, curing agents, fillers, lubricants, flame retardants, colorants, mold release agents, plasticizers, and other additives. Of course, this is possible, but in the case of the same composition, it is generally effective to adjust the heating of rolls, kneaders, coneaters, etc. and the mixing process when manufacturing the molding material. For example, in the case of rolls, it is possible to easily produce a molding material having an extrusion type flow within the above range by changing the temperature and cross-circuiting time of the rolls, as shown in Examples described later.

Thermosetting resins used in the present invention include thermosetting resins such as phenolic resins, melamine resins, urea resins, epoxy resins, unsaturated polyester resins, allyl resins, silicone resins, xylene resins, aniline resins, and crosslinked resins. Examples include thermoplastic resins such as polyethylene, polypropylene, polystyrene, and polyvinyl chloride with added agents. In particular, phenolic resin is suitable for extrusion molding using the extrusion molding machine incorporating the screw of the present invention.

The phenolic resin used in the present invention is a novolak resin obtained by reacting phenols such as phenol, cresol, xylenol, and resorcinol with formaldehydes such as an aqueous formaldehyde solution, halaformaldehyde, and trioxane using an acidic catalyst, or an alkaline catalyst. Any of the resol resins obtained by reacting with can be used.

If necessary, add a curing agent such as hexamine or paraformaldehyde to the above phenol resin.
Add 8 to 20 parts by weight to 0 parts by weight. If the amount of the curing agent is less than 8 parts by weight, the resulting molded product will have poor thermal rigidity;
On the other hand, if it exceeds 26 parts by weight, a large amount of ammonia will be generated during molding, and blisters will occur on the surface of the molded product, which is an undesirable tendency.

To this, a commonly known filler, Kiyone 1j, a mold release agent, a flame retardant and a coloring agent are added, kneaded and pulverized to obtain a phenolic resin molding material for extrusion molding.

All kneading and pulverization can be carried out by known methods. ff1lchi,
For mixing, heat roll, co-kneader, pulverization (speed mill,
A power mill etc. can be used.

The filler is particularly limited and only one car,
Carbon black, colloidal silica, glass powder, magnesia, basic magnesium silicate, magnesium carbonate, aluminum hydroxide, magnesium hydroxide, various silicates, alumina powder, calcium carbonate, cane powder,
Inorganic materials such as kaolin, celite, acid clay, ceramic fibers, asbestos, rock wool, glass fibers, carbon black (-), paper, (loop, cotton,
It can be used in the form of fibrous materials such as organic fibers, woven fabrics, non-woven fabrics, etc.

The lubricants are particularly limited (but include higher fatty acids such as stearic acid and palmitic acid, alkaline earth metal salts of higher fatty acids (calcium salts, magnesium salts), montanic acid wax, and amides of higher fatty acids. can be used.

These lubricants may be added by mixing them with the resin material and others, or, depending on the case, may be added after the molding material is prepared.

As the coloring agent, carbon black, spirisodo black, molybdenum red, phthalocyanine blue, phthalocyanino green, and nonza yellow can be used.

As the plasticizer, commonly used ones such as furfural, alkylphenol glycol, dibutyl phthalate, and p-)luenesulfonamide are effective.

There are no particular restrictions on flame retardants. These are antimony oxide, chlorinated roughin, loropentacyclotecan, tris (β-chloroethyl) phosphate, tris (dichloroglobil) phosphate, tris (2,3-dibromopropyl) phosphate, Tris (bromo, chloropropyl) phosphate, triphenyl phosphate, decabromodiphenyl ether, hexabromodiphenyl ether, red phosphorus, tin oxide, tin hydroxide, molybdenum oxide, ammonium molybdate, zirconium oxide, zirconium hydroxide, barium metaborate, boron Examples include acid zinc, etc.

The amount of the filler used is usually 100 to 400 parts by weight, preferably 150 to 250 parts by weight, per 100 parts by weight of the novolac type phenolic resin material. The lubricant is usually 0.5 to 2 parts per 100ii parts of novolac type phenolic resin.
．． 0 parts by weight are used. The amount of plasticizer used is usually 0.00 parts by weight per 100 parts by weight of novolac type phenolic resin.
It is 2 to 2.0 parts by weight. Furthermore, the amount of flame retardant used is usually 10 to 100 parts by weight of novolac type phenolic resin.
The range is 2 Oi parts.

The thermosetting resin molding material of the present invention is suitable as a molding material for the following continuous extrusion molding method for thermosetting resins.

The special feature of the first molding method lies in the structure of the tip of the extruder, and in particular the use of a screw having a smooth portion at the tip. As the extruder to be used, not only a single screw extruder but also a twin screw extruder or a multi-screw extruder in which the tip end is finally consolidated into a single screw extruder can be used. As for the internal structure of these extruders that can be used, there is no problem in providing a deaeration hole or a special cross-wire structure between the supply section and the measuring section at the tip of the extruder.

A typical screw is a screw C (hereinafter referred to as special screw) which has a smooth portion 4 at its tip as shown in Fig. 1. Consists of part 3. The smooth part 4 is the first
It may be of a type that starts from the end of the supply section as shown in the figure, from the end of the compression section as shown in FIG. 2, or from the middle of the metering section as shown in FIG.

In addition, the diameter of the screw in the smooth part 4 or the inner diameter of the cylinder in that part can be expanded or reduced in accordance with the outer diameter and inner diameter of the desired molded product, independently of the diameter of the screw bottom in the part with flights or the inner diameter of the cylinder. can be adjusted.

The special screw glue 4) has a compression ratio of usually 7 to 40, preferably 10 to 35, more preferably 15 to 25, and a compression ratio of 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 ID-15D, preferably 2D to 10D, more preferably 2D to It can be appropriately selected from the range of 7D. If the length of the smooth part at the tip of the screw is less than ID,
Deformation occurs in the molded product obtained after extrusion, making it difficult to continuously obtain good molded products. Also, the length of the smooth part is 15D
If the pressure is higher than that, the molding pressure becomes high and it is not practical from the viewpoint of mechanical strength of the extruder.

The compression ratio of the screw and the length of the smooth part are subject to various restrictions depending on the gap between the screw and the barrel in the smooth part, in other words, the thickness of the molded product, the extrusion speed, the characteristics of the material used, etc. The larger or smaller the compression ratio of the screw and the length of the smooth portion, the larger or smaller the back pressure applying function.

Too much back pressure is undesirable because excessive cross-talk occurs in the portions having flights, resulting in excessive heat generation and hardening of the material. On the other hand, if the back pressure is too small, compression and filling of the material and crosstalk will become insufficient, which is likewise undesirable. Adequate back pressure is necessary for compaction filling of the material and adequate cross-crossing.

That is, in order to achieve stable extrusion and a good product, an appropriate compression ratio of the screw and a suitable length of the smooth portion are required.

The larger or smaller the gap between the screw and the barrel in the smooth part, the lower or higher the extrusion speed, the lower or higher the viscosity of the material used, the lower or higher the curing speed of the material used, the lower or higher the extrusion speed. , the compression ratio of the screw and the length of the smooth part need to be increased or decreased.

The temperature settings for each part of the extruder will naturally vary depending on the combination of the characteristics of the material used, the compression ratio of the screw, the gap between the screw smooth part and the nozzle, the length of the smooth part, the extrusion speed, etc. The temperature setting of one part of the cylinder corresponding to the measuring part and the smooth part is usually in the range of 50 to 200°C, preferably 60 to 150°C. If the set temperature is below 50°C, the curing reaction of the resin will not proceed sufficiently, making it difficult to obtain a good molded product;
Thermosetting resins commonly used are sufficiently thermoset at temperatures up to 50°C, so there is no need to increase the temperature above that temperature.

This will be explained below using figures. 1 to 3 are side views showing an example of a screw having a smooth portion at its tip.

FIG. 4 shows one example of a preferred extrusion device, including a perspective view of a portion of the screw.

In the figure, the thermosetting resin material supplied from the hopper 5 is heated and melted by the heater 7 in the cylinder 6, and moves from the tip of the flight of the screw 8 in a helical shape to the smooth part 4, where the frictional resistance with the cylinder As a result, the gap created by the screw flight is narrowed and finally pressure fused. Next, the fused resin is shaped to the extent that it can maintain its own shape after extrusion while moving through the smooth part of the screw, and is extruded as a continuous pipe-shaped molded product 9 from the tip of the cylinder.

Normally, in the extrusion molding method for thermosetting resins, the resin is heated and melted in a cylinder, then introduced into the mold through an adapter and shaped into the final shape. Because the flow path of the resin changes in a complicated way, such as being squeezed with an adapter and re-expanded around a mandrel fixed with a spider, resin tends to stagnate, causing a localized curing reaction or a slight Changes in pressure and temperature can cause problems such as rapid curing reactions. In addition, in order to overcome the resistance caused by the complicated flow paths and extrude the resin while preventing stagnation, a large extrusion pressure is required and a special extrusion device is required. However, when using such a molding method, the extrusion speed is at most about 30 cm/min, and it is difficult to obtain a product with good roundness and thickness distribution.

According to the above method, the smooth part of the screw and the part of the cylinder in that part play the role of a mold, and the resin flow path is only the gap between the cylinder and the screw, so there is no stagnation of resin at all and only local It does not cause a rapid curing reaction due to changes in curing reaction, pressure, or temperature. In addition, since the smooth screw part, which corresponds to the no mandrel in the mold in general molding methods, is rotating, the frictional resistance between the hardened resin and the metal part is relatively small, and the extrusion pressure is the same as that obtained with a normal screw extruder. is sufficient. When such a method is used, an extrusion rate of 80 crIL/min can be easily obtained. The second molding method is characterized by the fact that the die, which is formed by a cylindrical part with an inner diameter approximately equal to the inner diameter of the cylinder of the extruder and a cylindrical part with an outer diameter approximately equal to the outer diameter of the bottom of the screw tip, is placed close to the tip of the screw. This is an extrusion molding method for thermosetting resin, in which the resin is mounted and shaped inside the die to the extent that it can maintain its own shape after extrusion.

This method is characterized by the structure of the die attached to the tip of the extruder and the method of attaching the die, and the extrusion device used can be the same as the one described above.

The screw may be a full-flight type screw that is normally used for extrusion molding of synthetic resins and has a flight all the way to the tip, or a torpedo type screw with a smooth part at the tip, and the shape of the tip may be cylindrical or conical. Figure 5 shows an example of a preferred device.

It is desirable that the distance between the screw tip and the cylindrical part of the die be as close as possible, but it is usually 0. (15 is also shown, and consists of a cylindrical part with an inner diameter equal to y on the cylinder inner diameter, a cylindrical part with an outer diameter equal to y on the bottom outer diameter of the screw tip, and a spider that fixes the cylindrical part. After passing through a part of the spider in a molten state, the resin introduced into the
It is shape-hardened before exiting. The length from the die inlet to the sparder is preferably as short as possible, as long as it is sufficient to sufficiently fix the cylindrical part of the die to prevent the formation of meat on the molded product. In addition, the length of the dice after the spider is usually ID-10D, preferably 2D to 7
D, more preferably selected from the range of 2D to 5D (here, D indicates the diameter of the cylinder).

If the length after the spider is less than ID, curing may be insufficient or the resin may not be sufficiently fused, making it impossible to obtain a good molded product. Moreover, when it exceeds 100, the back pressure becomes too large and extrusion becomes difficult.

In carrying out this method, the temperature settings for each part of the extrusion device are substantially the same as those described above, and the temperature setting for the die is usually in the range of 50 to 200°C, preferably 60 to 150°C. According to this method, there is almost no change in the flow path of the resin after the tip of the screw of the extruder, so there is no stagnation of resin at all, and localized curing reactions or rapid curing reactions due to changes in pressure or temperature are not caused. There is no.

As a modification of the second molding method described above, the cross section of the resin inlet is made equal to the circumferential cross section formed by the cylinder and screw tip of the extruder, and the subsequent resin flow path is smoothly changed, and the cross section of the outlet is A die designed to guide the material into a desired shape, such as an irregular shape such as a square, is installed close to the tip of the screw, and the material is shaped within the die to the extent that it can maintain its own shape after extrusion. You can also do it.

[Effect]

The feature of the present invention is that in continuous extrusion molding of thermosetting resin using a screw, by using a molding material prepared to have an extrusion flow in the range of 1 to 42 g, the appearance of the molded product is good, and it is continuously stable. The point is that it can be molded.

The molding material of the present invention has an extrusion flow of 1 to 42 g, preferably 1 to 38 g, particularly preferably 1 to 35 g. When the extrusion flow is less than 1 q, the surface of the molded product becomes rough and cavities occur. If the number is 42 or more, the molded product will swell and deform, and stable continuous molding over a long period of time will not be possible, and in some cases, the molded product will harden in the extrusion barrel, making molding impossible.

The thermosetting resin molding material for continuous extrusion molding using a screw according to the present invention has excellent extrudability, and the molded product has excellent surface smoothness. Furthermore, the molded product has high thermal rigidity and mechanical strength, and can be used for extruded tubes. , extrusion plates, and extrusion rods can be continuously and stably formed.

The present invention will be explained below with reference to Examples and Test Examples.

〔Example〕

Example 1 Novolac resin (Mitsui Toatsu Chemical Co., Ltd. #9000, softening point 95°C), hexamine, glass fiber (chopped strand), clay, asbestos, spirit black, stearic acid, magnesium stearate, silane cup Ring agent (Nippon Unicar Co., Ltd., product name A-LL)
on (hereinafter abbreviated as A-11(')O) was mixed at the blending ratio shown in Table 1.

The resulting mixture was roll-kneaded for 8 minutes under the temperature conditions of a front roll temperature of 95 to 100°C and a rear roll temperature of 55 to 60°C.

The mixed material was pulverized and sized using a power mill (screen 4rrL/m). The extrusion flow of the resulting granular molding material is
It was 2.09.

Example 2 A molding material was produced under the same conditions as in Example 1, except that the kneading time was changed to 4 minutes.

The extrusion flow of this was 30.09.

Example 3 Novolac resin (manufactured by Mitsui Toatsu Chemical Co., Ltd. #2000,
Hexamine, glass fiber (chopped strand), spirit black, stearic acid, and magnesium stearate were mixed in the proportions shown in Table 1.

After roll kneading the obtained mixture for 10 minutes at a temperature of 1OQ-110°C for the front roll and 55-60°C for the rear roll,
It was pulverized and sized using a power mill (using a 4m/m screen). The extrusion flow rate of the molding material obtained was 41.59.

Comparative Example 1 A molding material was produced under the same conditions as in Example 1 except that the crosstalk time was 9 minutes. The extrusion flow of this is 0
．． It was 59.

Comparative Example 2 A molding material was produced in the same manner as in Example 3, except that the crosstalk time was 8 minutes. The extrusion type flow of this is 43
．． It was 59.

Example 4 Bisphenol A type epoxy resin (manufactured by M Tokasei Co., Ltd.)
D-011, epoxy equivalent 475), ortho-cresol novolac type epoxy resin (Tobu Kasei (M) YDC
N-22OL, epoxy equivalent: 225), 4.4I-diaminodiphenylmethane, silica powder, montan wax, and carbon black were sufficiently mixed in a kneader at the blending ratios shown in Table 1.

The obtained mixture was pulverized and sized using a power mill to obtain a molding material. The extrusion flow of this product was 34.0 mm.

Example 5 Melamine formaldehyde resin liquid (formaldehyde/
Melamine ratio 2:1, solid content 90%) and cut dissolving pulp (α-cellulose) were placed in a mixer and mixed at 50° C. for 30 minutes. After drying this, zinc stearate and hexamine were added, and the mixture was ground using a ball mill to obtain a molding material.

The extrusion flow of this was 30.09.

The blending ratios and extrusion flows of Examples 1 to 5 and Comparative Examples 1 to 2 are summarized in Table 1 below.

Extrusion molding test example 1 A screw with a screw reduction ratio of 2.0 was used in an extruder with a diameter of 30 mA and a L/D = 22, and the molding materials shown in Table 1 were used. I molded my extrusion pipe and conducted various tests.

The extruder conditions are room temperature for 2D from the bottom of the hopper, then 60°C for IOD for 3, 80°C for 1l-14D, and 15S-18.
Extrusion was performed under the following conditions: D was set at 100°C, 19-22D was set at 140°C, and the screw rotation speed was 35 rpm.

The test results are shown in Table 2.

') 01- Various test methods Notes 1) Roundness: Hold the obtained pipe with a micrometer and find the difference (1) between its maximum diameter and minimum diameter. Also, insert a micrometer inside the hole and find the difference (2) between the maximum value and the highest value. Display the larger of (1) and (2) Note 2) Unbalanced meat: Measured according to JIS K 6911 Note 3)
Acetone extraction rate: The amount extracted by pulverizing the obtained pipe into approximately 100 meshes and extracting 5.0 ml of the pulverized material with 200 cc of tetrahydrofuran using a Soxhlet extractor for 6 hours.

Note 4) Heat treatment: The obtained pipe was treated at 1°C for 4 hours.

Extrusion Test Example 2 Supply section 3D by an extruder with a diameter of 40 mm and L/'D ==24.

Using a screw with a compression ratio of 2.0, which has a compression part 16D, a bottom diameter of 34mm, and a measuring part with a length of 5D, the cross section of the resin inlet has an outer diameter of 40mm and an inner diameter of 34mm. The cross section has an outer diameter of 46 mm, an inner diameter of 40 mm, and a length of the flow path that has the same cross section as the outlet side is 120 mm and a total length of 180 mm.
A die was installed at a position 0.5 mm from the tip of the screw, and using the molding materials shown in Table 1, pipes were molded and various tests were conducted.

The extruder conditions are: 2D from the bottom of the hopper is water-cooled, 3-10
D is 70℃, 11-16D is 85℃, 17-20D is 9
5℃, 21-24D is 105℃ and the die part is 30℃.
℃, and extrusion molding was performed at a screw rotation speed of 30 rpm.

The test results are shown in Table 3.

[Brief explanation of drawings]

FIGS. 1, 2, and 3 show an example of a screw having a smooth portion at the tip used for molding the thermosetting resin molding material of the present invention, and FIGS. 4 and 5 shows an example of a device suitable for the molding.

Claims (1)

[Claims] A screw with a smooth part at the tip is used, and the smooth part is shaped to such a degree that it can maintain its own shape after extrusion, or a cylindrical part with an inner diameter approximately equal to the inner diameter of the cylinder of the extruder and the bottom of the screw tip. A die having a die inlet formed by a cylindrical part having an outer diameter approximately equal to the outer diameter is installed close to the tip of the screw, and the product is shaped within the die to the extent that it can maintain its own shape after extrusion. It is a molding material for extrusion type flow test (JISK69
11) A thermosetting resin molding material suitable for continuous extrusion molding with a flow rate of 1 g to 42 g (however, the measurement conditions for the extrusion type flow test are a charging amount of 55 g, a temperature of 140°C, a pressure of 1
50kg/cm^2).