WO2003028911A1

WO2003028911A1 - Methods for producing resin granules densely filled with filler and molded product consisting thereof

Info

Publication number: WO2003028911A1
Application number: PCT/JP2002/009803
Authority: WO
Inventors: Katsuya Yamada; Takuma Yoshisaka; Kazuaki Ikeda
Original assignee: Sumitomo Electric Fine Polymer, Inc.
Priority date: 2001-09-27
Filing date: 2002-09-24
Publication date: 2003-04-10

Abstract

A method for producing resin granules having a filler filled in polymer at a high density. A method for producing a resin molded product by using the produced resin granules densely filled with a filler. A filler having a flat shape is used to process resin granules into a sheet-form molded product having an improved filler orientation, whereby a resin molded product making a good use of the above orientation is produced by a prepreg molding method. A resin molded product using an electromagnetic wave absorbing material as a filler can be universally used for electromagnetic wave absorption in a mobile communications equipment using a pseudo-microwave/ microwave region.

Description

TECHNICAL FIELD The present invention relates to a method for producing a high-filled fat powder granule and a molded product using the same.

TECHNICAL FIELD The present invention relates to a method for producing a resin particle in which a polymer is highly filled with a filler, and a method for producing a molded article using the particle. Background art

Recently, mobile communication devices that use the quasi-microwave to microwave band, such as mobile phones and PHS, are often used. In such devices that use electromagnetic waves, it is necessary to prevent magnetized objects and other magnetic field sources from adversely affecting other objects and electric circuits. There is a need for a material that suppresses the emission, reflection, and scattering of unnecessary electromagnetic waves from these sources, that is, a material that has electromagnetic wave absorption characteristics. Examples of materials having such electromagnetic wave absorption characteristics include a metal plate having a high magnetic permeability, a paint in which a magnetic powder is dispersed in an organic binder, a composition in which a magnetic powder is added to a polymer such as plastic or rubber, and the like. It has been known.

However, a high-permeability metal plate absorbs electromagnetic waves while reflecting electromagnetic waves, and thus has a problem in that it reverberates in the device and the electromagnetic waves are amplified. In addition, when a magnetic powder is dispersed in an organic binder to form a coating, it is necessary to apply the coating to a separately formed film / molded product, and the shape itself cannot be maintained.

The method of adding the magnetic powder into the polymer is convenient because of the flexibility in molding, but if the amount of the magnetic powder is increased to the extent that the electromagnetic wave absorption characteristics are sufficiently exhibited, it becomes difficult to mold, or the molding may become difficult. The problem is that the mechanical strength of the body is weak, brittle, and unfit for practical use.

Instead of the form of paint, it is conceivable to create a compound that combines a polymer and a filler such as a magnetic substance powder, and to freely form a molded body with this. In this case, as a method for highly filling the polymer with a filler such as a magnetic powder, It is common to use open rolls. However, this method requires manual switching of materials during the operation of the open mouth, and is a manufacturing method that relies on human labor. Also, the high-filling compounding of the filler has a problem that if the filler is added at once, the filler cannot enter the polymer and the polymer is peeled off from the roll together with the polymer. As a countermeasure, there is a means to divide the filler in several tens of small steps at a time and disperse it gradually. However, it is very time-consuming. Due to these problems, it can be said that this manufacturing method is not suitable for mass production.

In the case of a polymer mixture in which the amount of filler added is not so large, pelletization can be achieved by extruding with a feeder-ruder or the like. These pellets can be put into molding processes such as extrusion molding machines and injection molding. However, in the case of a high filler filling composition, the resin viscosity becomes extremely high due to a large amount of filler, and it is very difficult to extrude and pelletize it with a filler or the like. Disclosure of the invention

An object of the present invention is to provide a means for efficiently filling an organic polymer with a filler in order to obtain a filler-filled resin powder which can be formed into a free shape by itself. . As a means to do this, first, an organic polymer and additives other than fillers, such as an antioxidant, are mixed under pressure using a pressure kneader or a Banbury mixer, and the filler is added to this mixture using a pressure kneader or a Banbury mixer. Add and mix under pressure.After that, stop the pressurization and continue rotating the rotor of the pressure kneader or Banbury mixer, and pulverize the mixture by rotating the rotor to form a granular material. It is characterized by. The rotor mentioned here refers to a pressurized eder or a metal blade that forcibly agitates the material inside the Banbury mixer.

The filler used here can be of any kind as long as it is a filler that requires a high filling, but it is preferable to use a powder filler because the finished shape is a granular material. If the intended purpose of the powder is an electromagnetic wave absorber, magnetic powder is used. Here, a description will be given mainly of a magnetic substance powder for an electromagnetic wave absorber, but the present invention is not limited thereto. However, the use of magnetic ¹ biological powder as a filter is This is one of the preferable means for making the invention effective. Further, when the magnetic powder is a flat magnetic powder, the electromagnetic wave absorbing effect is further increased, so that a favorable result can be obtained.

In the case of the filler, high filling leads to adding the inherent properties of the filler to the molded body. Therefore, the higher the filling rate of the filler, the better, but it is preferable that the filler Z polymer> 30Z70 in volume ratio. In the finished molded product, the effect of the filler becomes clear when the content is 30 V o 1% or more.

Another invention of the present invention relates to a method of compressing a filler-filled resin powder produced using a magnetic material powder using an injection molding machine provided with a screw having a compression ratio of 1.5 or less. And heating and pressurizing the magnetic filler and the highly-filled resin powder in a compression molding die.

According to a further aspect of the present invention, there is provided a sheet-shaped molded body using the resin powder granules highly filled with a flat magnetic filler produced by the above-described manufacturing method, wherein the sheet-shaped flat magnetic material filler is formed. This is a method for producing a molded article highly oriented and highly filled with a flat magnetic filler, which is characterized in that a molded article highly oriented and highly filled is pre-prepared at room temperature to 120 ° C.

Still another invention of the present invention is a rubber extruder equipped with a resin powder granule highly filled with a flat magnetic filler, and a screw having the same groove depth and a smaller pitch toward the tip. The present invention is a method for producing a sheet-like molded article in which a flat magnetic filler is highly oriented and highly filled, characterized in that the molded article is rolled using a roll.

Further, a sheet-like molded body highly flattened and highly filled with a flat magnetic filler produced by the method for producing the sheet is subjected to pre-preda molding at room temperature to 120 ° C. It is a manufacturing method. BEST MODE FOR CARRYING OUT THE INVENTION

The polymer used in the present invention may be any polymer as long as it has a function of connecting the fillers and maintaining the shape. Polyol It is preferable to use an elastomer such as a fin or rubber. Particularly, chlorinated polyethylene, polyamide, polybutylene terephthalate, EPDM and the like are preferably used. As long as the filler is a powdery filler, the filler can be used as a highly-filled resin particle, but it has a particularly high electromagnetic wave absorbing property. Fine metal powders such as ferrite powder and permalloy powder, and metal oxides. It is preferable to use sardine powder. Further, it is more preferable that the shape of the powder is flat because the flat magnetic body is highly oriented parallel to the sheet surface by the means of the present invention, and exhibits excellent electromagnetic wave absorption performance. The larger the volume ratio of the filler and the polymer, the better the electromagnetic wave absorption performance as the ratio of the filler is higher, and the filler polymer = 20/80 or more, preferably 40/60 or more, and more preferably 550 or more. I do. In this case, during production, the volume ratio of the filler in the molded product may decrease slightly due to air entrapment or the like.However, when the molded product is formed, the volume of the filler in the total volume is 15% or more. It is preferably at least 30%, more preferably at least 40%.

If the polymer used here is in the shape of a powder or pellet, when the polymer and a large amount of filler are put into a pressure kneader or Banbury mixer at the same time, the rotor of the pressure kneader or Banbury mixer rotates. However, in some cases, the shear is not applied, and the polymer gels and does not enter a state where mixing is performed. In this case, use a pressure kneader or Banbury mixer to primarily mix the polymer and additives other than fillers such as antioxidants to solve this problem. If the polymer is a belt-like rubber, primary mixing is not required.

Next, the pressure kneader or the rotor of a Banbury mixer is turned until the temperature of the mixture obtained by the primary mixing reaches a predetermined temperature due to shearing heat. e / N i: 1: 1 alloy powder, diameter 20 μπι, thickness l / zm, specific gravity 8.35) are added little by little. As a result, the target filler has the highest filling ratio, and the mixture is mixed until the temperature of the mixture reaches a predetermined temperature. After that, the pressure lid is opened, the pressure is released, and the rotor is continuously rotated to form the mixture into a granular form. The filler-highly-filled resin granular material (filler: polymer volume ratio of 40: A mixture powder having a high filler concentration of 60 or more is obtained. Mixing with a pressurized ader or Banbury mixer Kneading progresses by giving a share to the material by the pressure of the rotor and the rotation of the rotor. Since it is very brittle, it is pulverized (depressurized pulverization) by the rotation of the rotor and becomes powdery. In other words, by utilizing the brittleness of the material, it is possible to pulverize the material that had been in a lump immediately after mixing into a fine size that can be put into the next process.

As described above, the resin particles which are highly filled with the filler generally do not melt or plasticize only by heating. It also has a very slippery property on glossy metal surfaces such as the inside of molding machines. Therefore, even if the powder is heated and the injection is attempted by the forward force of the screw of the molding machine, the powder will only be clogged at the tip of the molding machine and only go around the same place. Either the screw torque stops above the upper limit of the equipment, or the resin temperature rises due to friction, and the resin is decomposed.

Therefore, it is a feature of the method of the present invention that the screw mainly functions to feed the material into the compression molding die, and the material is heated and pressed in the compression molding die. Therefore, a screw with a compression ratio of 1.5 or less is used. Here, the compression ratio refers to groove depth at the root of the screw / groove depth near the tip of the screw. In the present invention, it is preferable that the groove depth is substantially the same from the root to the tip of the screw.

The set temperature of the heating cylinder of the molding machine varies depending on the type of resin used. In the case of the chlorinated polyethylene used in the examples, the front (supply side) temperature is set at 40 ° C to 120 ° C. C preferably at 50 ° C to 80 ° C, medium 'rear (discharge side) temperature at 10 ° C to 50 ° C, preferably 10 ° C to 30 ° C, like at the tip The lower the temperature, the better. The injection pressure is at least 30 MPa, preferably at least 5 OMPa, more preferably at least 100 MPa.

The heating temperature in the compression mold is preferably from 60 to 120 ° C., and the pressure is preferably from 25 to: L0 OMPa.

In addition, the highly filled magnetic material molded product obtained by the method of the present invention can be improved in heat resistance, strength, toughness and the like by irradiating it with ionizing radiation and crosslinking. .

The ionizing radiation may be a gamma source such as cobalt. It may be a beta ray by a speed gear.

As another molding method, there is pre-preda molding. This means preforms a flat, highly-filled, highly-filled sheet of magnetic material at room temperature to 120 ° C by pre-preda molding.This pre-preda molding refers to the process of once forming a sheet into a compressed air. Molding, vacuum forming, embossing, etc. For example, forming into a box-like shape.

Pre-preda molding can be performed using commercially available equipment. For example, air pressure molding can be carried out using a commercially available embossed carrier tape molding machine with an embossing function.

In normal pre-preda molding, for example, embossed carrier tape processing, the softening point of the polymer and the temperature around the melting point of the crystal are over a hundred. Mold at C level.

In the present invention, the molding temperature of the pre-preda molding is preferably 25 ° C. (room temperature) to 120 ° C., and 25 ° C. (room temperature) to 70 ° C. The temperature is more preferably 25 ° C (room temperature) to 50 ° C. The molding pressure is preferably set to 0.5 to 2.0 MPa.

As a material used for the pre-preda molding, it is preferable that a flat magnetic material filler-highly filled resin is previously formed into a sheet. Although it can be used as a sheet, a desired shape can be obtained by pre-preda molding as a molded body.

To extrude resin particles that are highly filled with flat magnetic filler, use a rubber extruder equipped with a screw that has the same groove depth and a smaller pitch toward the tip. Unless the material is compressed at a pressure of 30MPa or more at the extruder head, it is not possible to form a resin powder or granule highly filled with flat magnetic filler, but the depth of the screw groove shallower toward the tip. If you try to compress the material in the extruder, the material will be clogged in the extruder. To solve this problem, a screw with the same groove depth (compression ratio of approximately 1) and a smaller pitch toward the tip, that is, a variable pitch screw and a die diameter of the head Adjust so that the pressure is an appropriate value. If the lubricating temperature immediately after extrusion exceeds 100 ° C, the cohesive force of the resin will be weakened and it will not be possible to form the beads well, so the temperature should be adjusted so that the resin temperature immediately after extrusion becomes 100 ° C or less. Adjust and extrude.

Next, a rubber extruder is used to highly fill the flat magnetic filler formed into beads. The molded resin is rolled at a predetermined temperature through a pair of rolls having a narrow gap and formed into a sheet. The temperature of the roll is preferably from room temperature to 100 ° C., and the gap between the rolls is preferably from 0.2 to L mm.

The sheet-like formed body highly filled with the flat magnetic filler thus formed is subjected to pre-preda molding at room temperature to 120 ° C. as described above. The sheet obtained in this manner has a flat magnetic filler surface highly oriented parallel to the sheet surface, has excellent radio wave absorption performance, and has mechanical strength sufficient for practical use, and It has flexibility, that is, it has toughness.

Here, the definition of high orientation was determined as follows. An SEM photograph of the cross section of the sheet sample was taken, and 12 particles were extracted at equal intervals from one field of view, the angle of inclination with respect to the horizontal was measured, and the standard deviation of the 12 points was taken as the degree of non-orientation. Measurement result 1 From the data of 19 lots, the average of 119 lots of standard deviation is 2.8 °, and the standard deviation of 119 lots of standard deviation is 1.8 °. Therefore, from (average of σ) +3 = 8.1 °, the degree of non-orientation of 10 ° or less was defined as high orientation.

In addition, heat resistance, strength, and toughness can be improved by irradiating the sheet with an electron beam to crosslink.

(Example 1: Highly filled resin powder and granular material)

Using a 10-litre kneader DS-10 manufactured by Moriyama Co., Ltd., 100 parts by weight of chlorinated polyethylene powder Eraslen 301 (registered trademark manufactured by Showa Denko KK) was used as a stabilizer. 5 parts by weight of lead sulfate) and 0.5 parts by weight of Irganox 1076 (registered trademark of Ciba Geigy Corporation) as an antioxidant were added, and primary mixing was performed.

Next, an appropriate amount is taken out of the mixture obtained by the primary mixing, and is again put into the pressure kneader. The rotor is rotated until the polymer temperature reaches 80 ° C, and the flat permalloy powder (F e ^/ Ni is 1 alloy powder, diameter 20 πι, thickness l ^ urn) was added little by little, and finally, flat permalloy powder was added to 100 parts by weight of chlorinated polyethylene until it reached 1118 parts by weight. The mixture was further mixed until the polymer temperature reached 160 ° C. After that, open the pressure lid, release the pressure, and rotate the rotor. By continuing the inversion, the mixture was formed into a granular form, and as a result, the filler-filled resin particulate was obtained.

As described above, the filler obtained as a particulate form by depressurizing and pulverizing the highly-filled resin powder has a proportion of flat permalloy powder in the whole powder which is measured. The volume filling ratio was about 50%, and the molded body using the powdery granules had strong electromagnetic wave absorption characteristics, that is, characteristics of converting electromagnetic waves into heat energy.

(Example 2: Injection molding)

The filler-highly filled resin powder obtained in Example 1 was formed into a molded product using the following injection molding machine and conditions. The key points are the compression ratio of the screw and the temperature before and after the heating cylinder. Equipment: M-70C-TS, a precision injection molding machine for thermosetting resin manufactured by Meiki Seisakusho, Ltd. Working conditions: The cylinder has a diameter of 36 mm. The compression ratio of the screw is 1. The screw back pressure is 3.5 MPa and the resin is conveyed. The temperature at the front of the heating cylinder (supply side) was 55 ° C. The temperature inside and behind the heating cylinder (injection side) was kept at room temperature. The injection pressure was set at 155 MPa.

(Comparative Example 1)

The same conditions as in Example 2 were used except that the screw compression ratio was set to 2.

(Comparative Example 2)

The conditions were the same as in Example 2 except that the temperature at the front of the heating cylinder (supply side) was set at 20 ° C.

(Comparative Example 3)

The conditions were the same as in Example 2 except that the temperature at the rear (injection side) in the heating cylinder was set to 55 ° C.

However, under the conditions of Comparative Example 1, Comparative Example 2, and Comparative Example 3, the flat permalloy powder high-filled resin particles could not be fed well, and material clogging occurred on the way.

Under the conditions of Example 2, the flat permalloy powder-filled resin particles could be smoothly fed into the compression mold.

Then, after the flat permalloy powder highly-filled material powder is sent to the compression molding die, the flat permalloy powder high-filled material powder is heated to 55 ° C in the compression molding die, and the pressure is reduced to 0.5 ° C. By applying a pressure of 5 ton / cm ² (49 MPa), a molded article having electromagnetic wave absorption characteristics and excellent mechanical strength was obtained.

(Example 3: Sheet molding)

Next, a rubber extruder (screw diameter 60 mm, L / D: 12) manufactured by Mitsuba Seisakusho Co., Ltd. was connected to a variable pitch screw with a low compression ratio (the groove depth was almost the same [that is, the compression ratio force S was almost 1] Then, the flat permalloy powder-filled resin particles obtained in Example 1 were extruded and formed into beads.

The resulting bead was rolled with two 7-inch rolls with the gap between the rolls set to 0.5 mm and the temperature adjusted to 50 ° C. As a result, a flexible, flat permalloy powder-filled sheet was obtained. Obtained.

The flat permalloy powder is highly oriented parallel to the surface of the sheet, has excellent radio wave absorption performance, and has sufficient strength, mechanical strength to withstand practical use, and flexibility. That is, it was tough.

(Example 4: Pre-preda molding)

Extrusion of rubber with the flat permalloy powder-filled resin granules obtained in Example 1 fitted with a screw with the same groove depth used in Example 3 and with a smaller pitch toward the tip It was supplied to a machine and formed into beads. Subsequently, the bead was rolled with two 7-inch rolls adjusted at a spacing of 0.8 mra and a temperature of 50 ° C to obtain a soft, highly flat sheet of permalloy powder and a highly oriented sheet. Obtained.

This sheet is pressure-formed using a prototype machine with an embossing function added to the embossing taper HVT32DEV manufactured by Hagiwara Kogyo Co., Ltd., and has a length of 10 ram, a width of 15 ran and a depth of 3 mm. Formed into a shape. The conditions of the pressure forming were set as follows. The compressed air temperature is 25 ° C (room temperature). The compressed air forming pressure is 1.0 MPa. The embossing temperature is 60 ° C. Cooling temperature after embossing is 25 ° C (room temperature).

As a result, a highly filled and highly oriented molded article of flat perm mouth powder which maintained the flexibility of chlorinated polyethylene was obtained. This compact is a flat-shaped package filled in the compact. The flat surface of the one-malloy powder was oriented parallel to the surface of the molded body, was excellent in electromagnetic wave absorption, and had sufficient mechanical strength and flexibility for practical use. Industrial applicability

According to the production method of the present invention, a resin molded product utilizing characteristics of a filler can be obtained by highly filling a polymer with a filler having various characteristics.

Highly-filled resin particles obtained by combining a magnetic powder and a polymer have electromagnetic wave absorption characteristics, that is, characteristics of converting electromagnetic waves into heat energy, and are provided by a roll, an extruder, an injection molding machine, or the like. Since it can be formed into a free shape by itself, it can be used in casings of mobile communication devices such as mobile phones and PHS, which use the quasi-microwave to microwave band, and other devices that use electromagnetic waves. It has high utility value. ADVANTAGE OF THE INVENTION According to the method of this invention, a magnetic substance powder can be highly filled in an organic polymer, and the molded object molded using the obtained resin powder has a strong electromagnetic wave absorption characteristic, and Excellent mechanical strength. In particular, since a flat magnetic powder can be used and oriented parallel to the surface of the molded body, a molded body having excellent electromagnetic wave absorption performance can be obtained.

Claims

The scope of the claims

1. Using a pressure-mixer or a Banbury mixer, first mix the polymer and additives other than the filler under pressure, and add a filler to the mixture using a pressure kneader or a Banbury mixer. The mixture is depressurized and pulverized to a powdery state by stopping the pressurization and continuing to rotate the pressurized kneader or the rotor of a Banbury mixer. A method for producing a highly filled resin powder.

2. The method according to claim 1, wherein the filler is a magnetic filler.

3. The method according to claim 2, wherein the filler is a flat magnetic filler.

4. The method for producing a filler-highly filled resin powder according to any one of claims 1 to 3, wherein the filler is a filler Z polymer> 30/70 in a volume ratio.

5. The magnetic material filler produced by the method of claim 2 and the highly filled resin particles are fed into a compression molding die using an injection molding machine provided with a screw having a compression ratio of 1.5 or less. A method for producing a molded article highly filled with a magnetic filler, characterized by heating and pressurizing a magnetic filler—a highly filled resin powder in a compression mold.

6. A sheet-shaped molded article having a highly oriented and highly filled flat magnetic filler, which is made of a resin powder and a highly filled flat magnetic filler prepared by the manufacturing method of claim 3, A method for producing a molded product in which a flat magnetic filler is highly oriented and highly filled, which is characterized by performing pre-preda molding at room temperature to 120 ° C.

7. A resin powder and granular material, which is highly filled with a flat magnetic filler, prepared by the manufacturing method of claim 3, is a rubber with a screw having the same groove depth and a smaller pitch toward the tip. A method for producing a sheet-shaped, flat magnetic filler highly oriented and highly filled with a sheet-shaped, flat magnetic filler, wherein the molded body is supplied to an extruder for use, molded and rolled using a roll.

8. The flattened sheet produced by the manufacturing method according to claim 7, wherein the sheet-shaped formed body highly oriented and filled with the flat magnetic filler is pre-preda molded at room temperature to 120 ° C. A method for producing a molded article in which a highly magnetic filler is highly oriented and highly filled.