JPH07329150A - Method and device for extruding melting resin of powder material - Google Patents

Abstract

PURPOSE:To obtain a melting resin which has attained to a quality standard by directly melting and kneading a powder material without pelletizing it. CONSTITUTION:A powder material 20 supplied into a cylinder 1 enforcedly is melted and kneaded. A surface area of a melting resin 30 is expanded by aggregates 901 and 902 of a pin string having holes. A monomer, an oligomer, etc., are efficiently deaerated from vent ports 71 and 72 so as to obtain the melting resin 30 which has attained to a standard.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for extruding a molten resin using a powder raw material, and in particular, directly melting and kneading the powder raw material in a cylinder without granulating the powder raw material.
The present invention relates to a new improvement for extruding a molten resin for molding a sheet or the like that has achieved a standard such as an oligomer.

[0002]

2. Description of the Related Art As a conventional method for producing this type of sheet, for example, the method disclosed in JP-A-2-219624 can be cited. That is, as disclosed from page 6, line 14 of this publication, a free charge hopper is formed by using pellet raw materials processed into low oligomers by separately provided granulator equipment. Owing to the single-screw one-vent port extruder, T-die and sheet polishing roll stand, a sheet having an oligomer content of 0.4% by weight or less was produced.

[0003]

Since the conventional sheet manufacturing method is configured as described above, there are the following problems. That is, when powder raw material (bulk specific gravity of 0.4 or less) with a residual monomer of about 7,000 PPM is used in the hopper of a conventional single-screw one-vent port extruder, the bulk specific gravity is low and the raw material shape (bead shape) is different. From
The amount of extrusion per screw rotation speed (extrusion efficiency) is remarkably reduced (about 50%), and at the same time, the residual monomer does not reach the target value of 1000 PPM or less, and even if the sheet is directly formed, it does not pass the usage standard, and it is a powder raw material. It was not possible to carry out direct shaping of the sheet by means of a single-screw extruder.

The present invention has been made in order to solve the above problems, and in particular, a sheet in which a powder raw material is directly melted and kneaded in a cylinder without being granulated to achieve a standard such as an oligomer. It is an object of the present invention to provide a molten resin extrusion method and apparatus using a powder raw material for extruding a molten resin for molding the above.

[0005]

A method for extruding a molten resin using a powder raw material according to the present invention is a method in which a powder raw material in a hopper is directly fed to a single screw in a cylinder under heating through a forced feeding means to melt the powder raw material.・ The first step of kneading,
The molten resin obtained in the first step is passed through an aggregate of pin rows with holes provided on the outer periphery of the pin position in the single screw, and the vent of the cylinder located downstream of the aggregate of pin rows with holes. The method comprises a second step of degassing at a port, and is a method of extruding the molten resin from the cylinder to the outside.

More specifically, the powder raw material is A
BS (acrylonitrile, butadiene, styrene), P
S (polystyrene), PP (polypropylene), PA
(Polyamide), PMMA (polymethamethyl acrylate), and LLDPE (linear low density polyethylene).

More specifically, the second step is a method performed a plurality of times in the cylinder.

A molten resin extruding apparatus using a powder raw material according to the present invention has a hopper provided on the upstream side of a cylinder containing one single screw, and a powder raw material provided in the hopper into the cylinder. Forced supply means for supplying, a vent port provided on the outer periphery of the cylinder, and an assembly of pin rows with holes provided on the outer periphery of the pin position in the single screw and located on the upstream side of the vent port. The vent port degasses the molten resin that has passed through the aggregate of pin rows with holes.

More specifically, the first cross-sectional area of the single screw at the pin position where the aggregate of pin rows with holes is provided is the second cross-sectional area of the single screw upstream of the pin position. The configuration is different from.

More specifically, the first cross-sectional area is larger than the second cross-sectional area.

More specifically, the single screw at the pin position where the aggregate of the pin row with holes is provided is not provided with a flight.

More specifically, the aggregate of the pin row with holes is provided in a radial direction orthogonal to the axial direction of the cylinder.

More specifically, the vent port is provided at one or a plurality of locations in the cylinder, and the aggregate of the pin row with holes is located upstream of each vent port.

More specifically, in the aggregate of the holed pin row, a plurality of holed pins are driven in the radial direction of the single screw to form a row of holed pins, and The configuration is one column or a plurality of columns.

More specifically, the direction of the holes of the aggregate of the holed pin rows is upward in the order of the holed pin rows,
The configuration is arranged downward, upward ...

[0016]

In the molten resin extruding apparatus using the powder raw material according to the present invention, the assembly of the pin row with holes provided on the outer periphery of the pin position of one single screw is the same as the cylinder containing the single screw. Since it is located on the upstream side of the vent port, the powder raw material in the hopper is forcibly supplied into the cylinder under heating by the compulsory supply means, and the molten resin melted and kneaded in this cylinder is stored in the pin row with holes. At the moment of passing through the assembly, a space is generated on the back side of the pin or on the downstream side of the inclined hole of the pin, the surface area of the molten resin is remarkably expanded, and degassing from the vent port is performed with high efficiency. As a result, residual monomers, water, volatile components such as oligomers were sufficiently removed, and the molten resin directly melted from the powder raw material was used to achieve the standard value without using the conventional granulation process. Coatings, laminated hollow containers and injection molded articles can be directly molded.

[0017]

The preferred embodiments of the molten resin extrusion method and apparatus using the powder raw material according to the present invention will be described in detail below with reference to the drawings. A reference numeral 1 in FIGS. 1 and 2 is a long cylinder having an external heater 2 for heating, and in the cylinder 1, one single screw 3 having a flight 4 is rotatably mounted. It is provided.

At the most upstream position of the cylinder 1, a hopper 6 incorporating a well-known forced supply means 5 such as a screw feeder is attached, and a downstream side of the hopper 6 is provided with a predetermined interval at a first vent port. 7 ₁ and a second vent port 7 ₂ are provided.

The single screw 3 comprises first, second and third screw segments 3A, 3B, which are arranged in series with each other.
3C, the first and second screw segments 3
First and second pin positions 3Aa formed downstream of A and 3B
_As shown in FIG. 2, ₁ and 3Aa ₂ are provided with a plurality of pin 9 with holes driven in the radial direction of the single screw 3 and also provided in the axial direction. 9 is formed with an inclined hole 9a shown in FIGS. 1, 2 and 5. A pin 9 is also provided at the second pin position 3Aa ₂ . That is, a plurality of pins 9 are provided at the pin positions (3Aa ₁ , 3Aa ₂ ) on the outer periphery of the screw 3, and the mounting positions of the pins 9 are increased by increasing the number of screw segments 3A. It may be one place or arbitrary plural places. The column 9A ₁ perforated pin by the respective perforated pin 9, 9A _2, constitute ..., column 9A ₁ of a plurality of perforated pins, 9A _2, first independent to each other by ..., Second pin group assembly 90 with holes
₁ , 90 ₂ ... Are respectively configured. Also, cylinder 1
The length of each of the vent ports 7 ₁ , 7 ₂ , ...
The number of ··· is not limited to two, but can be any number of more.

The diameter (that is, the first cross-sectional area) of each of the pin positions 3Aa ₁ and 3Aa ₂ is the upstream position 3a ₁ and 3b ₂ thereof.
Is larger than the diameter (i.e., the second cross-sectional area) of each of the pin positions 3Aa ₁ and 3Aa ₂ , and the flight 4 is not formed by only the pin 9. Note that the size of each cross-sectional area described above is not limited to the above-described relationship, and the case where the relationship is the opposite of the above (first cross-sectional area <second cross-sectional area) can be used. That is, the above-mentioned cross-sectional areas are different from each other. In addition, as a result of various experiments, the first
Even when they are equal to each other, such as the cross-sectional area = the second cross-sectional area,
It was confirmed that it was effective. That is, the first cross section>
In the case of the second cross-sectional area, the pin flow velocity of the molten resin becomes slow. Further, when the first cross-sectional area is smaller than the second cross-sectional area, the flow velocity of the molten resin passing through the pin is high, and when the above is equal, the flow velocity of the molten resin on the pin side is the same as that on the screw side. That is, the kneading effect of the molten resin can be changed by the depth of the flight 4 of the screw 3.

Each of the vent ports 7 ₁ and 7 ₂ is provided with a pump 11 driven by a motor 10, and the action of the pump 11 evacuates the vent ports 7 ₁ and 7 ₂ .

Next, the operation will be described. First, ABS (acrylonitrile, butadiene, styrene) supplied in the hopper 6, P. S (polystyrene), P. The powder raw material 20 made of any one of P (polypropylene), PA (polyamide), PMMA (polymethamethyl acrylate) and LLDPE (linear low density polyethylene) is supplied to the inside of the cylinder 1 under heating by the forced supply means 5. And is melted and mixed. The melted and mixed molten resin 30 is conveyed to the downstream side, passes through the first taper 3X of the single screw 3 and passes through the first hole pin assembly 90 ₁ and then the first hole pin 9 A space is generated on the back side or on the opposite side (downstream side) of the inclined hole 9a, the surface area of the molten resin 30 is remarkably expanded, and deaeration is performed. Residual monomers, water, oligomers, etc. due to this deaeration are generated in the first vent port. Degassed from 7 ₁ .

Furthermore, the residual monomer could not be degassed with the first vent port ₇₁ is inside the molten resin in the first vent port ₇₁ portion is re-kneaded by a single screw 3 until ₂ second vent port 7 The volatile components, residual monomer water, oligomers, etc., which have been used, are exposed through the second pin-port aggregate 90 ₂ and the second vent port 7 _{2 and} are deaerated again. Therefore, as shown in FIG. 6, the molten resin sheet 30A discharged from the die 40 of the cylinder 1 is stretched to the sheet 30B which has achieved the reference value of residual monomer and the like through the well-known polishing roller 41 and stretching roller 42. .

[0024]

[Experimental example] In addition, according to the experimental result by the applicant, ABS
At the tip of a 2 vent port single screw extruder (r / D = 34) with powder material (residual monomer content 7100PPM) set to 1st vent port 7 vacuum degree 640mmAg, 2nd vent port 8 vacuum degree 705mmAg A gear pump and a T-die sheet polishing roll stand fixed length cutting machine were attached to form a 3MM thick sheet for refrigerators, and residual monomer was measured and calculated by a gas chromatography test, and it was confirmed that the average was reduced to 965 PPM. done. Further, when a powder raw material having a high residual monomer content ratio among powder raw materials is used or when the residual monomer content ratio in the sheet is further reduced, a third vent port 7 ₃ can be provided. It is also effective to increase the deaeration time without sealing the molten resin between the vent port 7 ₁ and the second vent port 7 ₂ .

The above-mentioned aggregate of pin rows with holes 90 ₁ , 9
0 ₂ part of the arrangement, each pin position 3A single screw 3
The case where the flight 4 is not formed in the a ₁ and 3Aa ₂ has been described. However, as shown in FIG. 3, the pins 9 are arranged along the axial direction between the flights 4 and 4 and in the axial direction. And a configuration in which each pin 9 is arranged so as to be perpendicular to the plane of the flight 4 between the flights 4 and 4, as shown in FIG. The pin 9 is provided on each holding plate 60 that is detachably attached to the cylinder 3, and the holding plate 60 is detached from the cylinder 3 to facilitate cleaning after use. The action of can be obtained. In addition, each pin 9 described above is connected to each vent port 7 ₁ ,
Are provided a plurality of rows on the circumference of the 7 ₂ just before the screw 3, but the direction of the inclined holes 9a of the pin 9, column 9A ₁ of each perforated pins as shown in FIGS. 1 and 5 above, 9A ₂ is not limited to the upward and downward mixed configuration, but all may be upward or downward, but in any configuration,
The final row of pins 9A ₁ , 9A ₂ , of each of the plurality of pins 9
The direction of the inclined hole 9a must be upward.
Further, although not shown, each pin 9 is not limited to the structure in which the single screw 3 is driven in the radial direction, and may be driven in a direction other than the radial direction.

[0026]

The molten resin extruding method and apparatus using the powder raw material according to the present invention expands the surface area of the molten resin obtained by melting the powder raw material through each pin, and increases the surface area of the molten resin by the vent port. In order to efficiently degas oligomers and the like, it is possible to mold sheets, films, wire coatings, laminated hollow containers, injection molded products, etc., using molten resin of quality standards, which was previously impossible with single-screw extruders. It can be obtained by omitting the granulation process, and the electricity cost, cooling water cost, labor cost, consumable cost, and equipment depreciation cost that have been required in the conventional granulation process can be saved. In addition, according to a trial calculation by the applicant, the extrusion amount is 800 kg.
The granulation amount of / H is about 850 yen / kg. Therefore, a facility that produces sheets with an extrusion rate of 800 kg / hr for one year (72
00Hr) Assuming that it operates, the saving cost is 80
0 kg / H × 7200 Hr × 50 yen / kg ≈ 288 million yen / year. For the time being, considering the initial equipment cost, the equipment difference between the twin-screw vent extruder, the quantitative feeder, the single-screw multi-vent extruder, and the screw feeder becomes about 20,000 in the 800 kg / H production line using ABS raw material.
From 1,000 yen to 30,000,000 yen, and in the case of molding a four-kind five-layer sheet using three extruders, an effect such as a facility difference of about 50,000,000 yen can be obtained.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a molten resin extrusion apparatus using a powder raw material according to the present invention.

FIG. 2 is an enlarged cross-sectional view showing a main part of FIG.

FIG. 3 is a sectional view showing another embodiment.

FIG. 4 is a sectional view showing another embodiment.

FIG. 5 is a cross-sectional view of another embodiment.

FIG. 6 is a schematic configuration diagram for manufacturing a sheet.

[Explanation of symbols]

1 Cylinder 3 Single screw 3Aa, 3Ba Pin position 4 Flight 5 Forced supply means 6 Hopper 7 ₁ , 7 ₂ Vent port 9 Hole pin 20 Powder raw material 30 Molten resin 9A ₁ , 9A ₂ , ... Row of pin pins 90 ₁ , 90 ₂ , ... Assembly of pin rows with holes

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display area B29K 33:00 77:00

Claims (11)

[Claims] 1. A powder raw material (20) in a hopper (6) is directly supplied to a single screw (3) in a heated cylinder (1) through a forced supply means (5) for melting and kneading. A set of a pin row with holes in which the first step and the molten resin (30) obtained in the first step are provided on the outer periphery of the pin positions (3Aa ₁ , 3Aa ₂ , ...) In the single screw (3). body (90 _1, 90 _2, ...) collection of the perforated pin rows with passing (90 _1, 90 _2,...) the vent port of the cylinder (1) located downstream of (7 _1, 7 _2, becomes more and second step of performing degassing at..), was used powder material, characterized in that to said extruded molten resin (30) from the cylinder (1) to the outside melt Resin extrusion method. 2. The powder raw material (30) is made of ABS (acrylonitrile, butadiene, styrene), PS (polystyrene), PP (polypropylene), PA (polyamide), PMMA (polymetamethyl acrylate) and LLDPE (linear). 2. A method for extruding a molten resin using a powder raw material according to claim 1, which is made of an olefin-based resin made of any one of low density polyethylene). 3. The molten resin extrusion method using a powder raw material according to claim 1, wherein the second step is performed a plurality of times in the cylinder (1). 4. A hopper (6) provided upstream of a cylinder (1) containing one single screw (3), and a powder raw material (20) provided in the hopper (6). Forced supply means (5) for supplying into the cylinder (1), and vent ports (7 ₁ , 7 ₂ ...) provided on the outer periphery of the cylinder (1)
And the pin position (3Aa ₁ , 3Aa in the single screw (3)
₂ , ...) provided on the outer circumference of the vent port (7 ₁ , 7 ₂ , ...)
An assembly of pin rows with holes (90 ₁ , 90 ₂ , ...
.), And the aggregate of pin rows with holes (90 ₁ , 90 ₂ , ...
・) Degassing of the molten resin (30) that has passed through
₁ , 7 ₂ , ...), and a molten resin extrusion apparatus using a powder material. 5. The aggregate of pin rows with holes (90 ₁ , 90 ₂ , ...
The first cross-sectional area of the single screw (3) at the pin positions (3Aa ₁ , 3Aa ₂ , ...) provided with () is the pin positions (3Aa ₁ , 3Aa ₂ ,
The second cross-sectional area of the single screw (3) on the upstream side (3a ₁ , 3a ₂ , ...) of (...) Is configured to be different. Molten resin extrusion equipment using powder raw materials. 6. The molten resin extrusion apparatus using a powder raw material according to claim 5, wherein the first cross-sectional area is larger than the second cross-sectional area. 7. The aggregate of pin rows with holes (90 ₁ , 90 ₂ , ...
5. The single screw (3) at the pin position (3Aa ₁ , 3Aa ₂ , ...) provided with () is provided with no flight (4). 7. A molten resin extrusion device using the powder raw material according to any one of items 1 to 6. 8. An aggregate of the pin row with holes (90 ₁ , 90 ₂ , ...
) Is provided in the radial direction at right angles to the axial direction of the cylinder (1), and the molten resin extrusion apparatus using the powder raw material according to any one of claims 4 to 7. 9. The vent port (7 ₁ , 7 ₂ , ...) Is provided in the cylinder (1) at one location or at a plurality of locations, and the aggregate of pin rows with holes (90 ₁ , 90 ₂ , ...・ ・) Is each vent port
(7 _1, 7 _2,...) Molten resin extrusion apparatus using the powder material according to any one of claims 4 to 8, characterized in that positioned upstream of. 10. The aggregate of pin rows with holes (90 ₁ , 90 ₂ , ...
・ ・) Is a single screw (3) with multiple pin (9)
Row of pin with holes (9A ₁ , 9A ₂ , ...) is formed by driving in the radial direction of, and the row of pin with holes (9A ₁ , 9A ₂ , ...) is 1
The molten resin extrusion apparatus using the powder raw material according to any one of claims 4 to 9, wherein the molten resin extrusion apparatus is configured by a row or a plurality of rows. 11. An assembly (90 ₁ , 90 ₂ , ...) Of the pin row with holes.
..) are arranged in the order of the row of pins with holes (9A ₁ , 9A ₂ , ...) In the order of upward, downward, upward ... A molten resin extrusion apparatus using the powder raw material according to any one of 4 to 10.