JPH0970872A - Powder resin extruder and extrusion method using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance extrusion efficiency without generating the mixing with a non-molten resin or vent-up by constituting the screw of the first kneading zone of a biaxial rotary extruder by a combination of two kinds of kneading discs respectively specified in nondimensional pressure gradient. SOLUTION: A powdery resin extruder is set to a biaxial rotary type obtaining sufficient feed force to a powder resin and the screw constitution of a first kneading zone is composed of a combination of kneading discs A, B. In the kneading disc (A), a ratio L/D of the length L and diameter D thereof is set to 0.5-2 and the nondimensional pressure gradient at a time of 0.01 in nondimensional extrusion quantity is set to 0-10. In the kneading disk (B), nondimensional pressure gradient at a time of 0.01 in nondimensional extrusion quantity is set to 0-1,000. By this combination, proper kneading pressure is obtained and extrusion efficiency can be enhanced without generating trouble.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an extruder suitable for melting, kneading and extruding powdery resin, and a method for melting, kneading and extruding powdery resin using this extruder.

[0002]

2. Description of the Related Art Generally, a powdery resin is granulated through an extruder and then used for production of a product by a molding machine.

[0003] By the way, the powder resin has a characteristic that it is less likely to penetrate into the screw of the extruder as compared with the pellet resin. The smaller the apparent specific gravity and the smaller the average particle diameter of the powdery resin, the worse the bite into the screw of the extruder and the lower the productivity of the granulated product. Although such powdery resin extrusion technology is an important technology for molding, few technologies have been published so far.

Conventionally, the following is known as the extrusion technique of the powdery resin.

(1) According to the technical data of the German company Warner & Friedler, when the powdery resin is extruded, the screw constitution of the first kneading zone of the extruder indicates the kneading disk (B) of the present invention. It is disclosed that only those that fall into the category should be included.

(2) "Molding processing Symposia 94 C2
No. 11 ", the first kneading zone is obtained by variously combining a reverse feed screw with a kneading disk (B) in the present invention or a kneading disk (A) in the present invention. The results of examining the plasticizing behavior of the polypropylene powder in the plasticizing zone by changing the screw configuration of No. 3 are disclosed.

(3) "Molding processing Symposia 93 S2
04 ", there are various types of reverse feed screws, including those belonging to the category of the kneading disc (B) of the present invention, those belonging to the category of the kneading disc (A) of the present invention, rotors, and reverse flow kneading discs. The results of studying the plasticizing behavior of the polypropylene powder in the plasticizing zone by changing the screw configuration of the first kneading zone by combining them are disclosed.

[0008]

However, in the case of the screw constitution of the above (1), since a high resin pressure can be obtained in the first kneading zone, the productivity is improved, but the kneading force tends to be insufficient, and the powdery state There is a problem that it is difficult to completely melt the resin, unmelted resin is mixed and extruded, and bent up is likely to occur due to high resin pressure.

The above techniques (2) and (3) are studies on the behavior of the plasticized state in the plasticizing zone, and there is no disclosure about improving the productivity. Also,
Although it is premised that the reverse feed screw is arranged in both cases, according to the knowledge of the present inventor, good productivity cannot be obtained with such a screw configuration.

The present invention improves the extrusion efficiency without causing troubles such as mixing of unmelted resin and vent up, particularly in the powdery resin extrusion process, and the productivity of pelletized resin and the like that is carried out through this extrusion. The purpose is to improve.

[0011]

Therefore, in the present invention, in the present invention, in the twin screw rotary extruder, the screw constitution of the first kneading zone has a dimensionless pressure when the dimensionless extrusion amount is 0.01. The gradient is 0 to -100, and the ratio of length L to diameter D is L / D
Of 0.5 to 2 and a kneading disc (B) having a dimensionless pressure gradient of more than 0 and 1000 or less when the dimensionless extrusion amount is 0.01, or The above-mentioned kneading discs (A) and (B) have a ratio L / D of length L and diameter D of 1.5.
The extruder for powdery resin is configured by further adding the following progressive screw. The present invention also provides an extrusion method suitable for extruding a powdery resin using these powdery resin extruders.

The present invention will be further described with reference to FIGS.

The powdery resin extruder 1 is a twin-screw rotary extruder so that a sufficient conveying force for the powdery resin can be obtained, and it may be a co-rotating type or a counter-rotating type, but in general, Is a co-rotating type.

The powdery resin extruder 1 is generally used to obtain a pellet resin, but the present invention is not limited to this, and a sheet or film can be formed. Good. For example, Warner
To obtain an extruder for powdery resin of the present invention by improving the screw constitution in the first kneading zone such as ZSK series manufactured by And Frederer, TEM series manufactured by Toshiba Machine Co., Ltd., and TEX series manufactured by Nippon Steel Co., Ltd. You can

The length of the powdery resin extruder 1 is such that L / D (L = length, D = screw diameter) is 10 to 60.
It is preferable that the length is When L / D is less than 10, deaeration and side feed are difficult to occur, and when L / D of the present powdery resin extruder 1 is more than 60, the residence time of the resin becomes long and the resin is apt to deteriorate.

In the present invention, the screw structure of the first kneading zone is particularly characteristic. The first kneading zone is a region where the powdery resin supplied from the main hopper 2 shown in FIG. 1 is first heated and kneaded, and depends on the length of the powdery resin extruder 1.
From the center position of the barrel in which the main hopper 2 is provided, the L / D of the extruder for powdery resin is in the range of 4 to 32, and preferably L / D is in the range of 6 to 28.

The screw structure of the first kneading zone in the present invention is a combination of a kneading disc (A) and a kneading disc (B) described later, or in addition to the above kneading discs (A) and (B). It is also a combination of progressive screws.

The kneading disc (A) used in the present invention has a dimensionless pressure gradient in the screw axis direction obtained by a two-dimensional pressure distribution calculation method in the screw axis direction and the radial direction of the kneading disc. Extrusion rate 0.01
It is a kneading disc having a range of 0 to -100 at the time. The two-dimensional pressure distribution is, for example,
"In, published by J.L. White and others.
ten. Polym. Pro (1987) 4 "second
It can be calculated by the pressure distribution calculation of the kneading disk described on page 07. This calculation model is a temperature, non-meshing, two-dimensional model, or Newtonian model.

The dimensionless extrusion rate can be calculated by the following equation. However, DLQ is a dimensionless extrusion rate, Q is an extrusion rate (m ³ / h), D is a screw diameter (m), and n is a screw rotation speed (rps).

DLQ = (Q / 3600) / (D × D ×
D) / (2 × 3.14 × n)

The dimensionless pressure gradient can be calculated by the following equation. However, DLDP is a dimensionless pressure gradient, DPD
Z is the pressure gradient in the screw axial direction (Pa / m), D is the screw diameter (m), η is the viscosity of the resin (Pa / s), and n is the screw rotational speed (rps).

DLDP = DPDZ × D / (η × 2 × 3.14 × n)

The kneading disc (A) has a ratio L / D of the length L to the diameter D (see FIG. 3) of 0.5 to 2
It is in the range of. Kneading disk (A)
The range of the dimensionless pressure gradient is 0 to -100, preferably 0 to -30. If the L / D of the kneading disc (A) is too large or too small, the kneading force will be insufficient, and unmelted resin will be easily mixed and extruded.

Incidentally, as a specific condition which easily satisfies the condition of the kneading disk (A) having a dimensionless pressure gradient of 0 to -100 when the dimensionless extrusion amount is 0.01, two or more blades 3 are used. And, the mutual angle θ of the blades 3 is 90 degrees (neutral), the blade 3 is one, and the blade 3 is
The mutual angle θ of the blades is 0 degree or 180 degrees (wide), the number of the blades 3 is two or more, and the mutual angle of the blades 3 is less than 25 degrees (see FIGS. 2 and 3).

In the present invention, the kneading disc (B) combined with the kneading disc (A) is
The dimensionless pressure gradient when the dimensionless extrusion rate is 0.01 is larger than 0, and the upper limit of this dimensionless pressure gradient is not particularly limited, but generally the upper limit is about 1000. As a concrete condition which is easy to satisfy this condition, FIG.
Is to set the mutual angle θ of the blades 3 to 25 to 75 degrees (kneading light), and generally to set the mutual angle θ of the blades 3 to 30 degrees, 45 degrees or 60 degrees.

The length of the kneading disc (B) is not particularly limited, but the ratio L / D of the length L to the diameter D (see FIG. 3) is about 0.3 to 3. Is preferred.

The screw structure of the first kneading zone in the present invention is a combination of one or more kinds of the above kneading disks (A) and one or more kinds of the above kneading disks (B). It is a thing. By this combination, an appropriate kneading force and an appropriate resin pressure can be obtained, and the extrusion efficiency can be improved without causing trouble such as mixing of unmelted resin and vent-up.

The kneading discs (A) and (B) may be combined as long as they exist, in that order, the number of kneading discs (A) and (B), each kneading disc (A). , (B), the number of blades 3 may be appropriately selected.

In the present invention, a progressive screw is further added to the combination of the kneading discs (A) and (B) within a range in which the ratio L / D of the length L to the diameter D is 1.5 or less. You may combine it. This progressive screw may be a first screw or a second screw.

The length of the screw constituent portion of the kneading disks (A) and (B) in the first kneading zone or a combination of the progressive screw and the forward screw is L / D (L = length, D = Screw diameter) is 2-1
It is preferably in the range of 2. If this is too small, melting of the powdery resin tends to be insufficient, and venting is likely to occur. Conversely, if it is too large, the resin temperature will increase, and the resin will be likely to deteriorate.

The upstream side of the first kneading zone of the present powdery resin extruder 1 is provided with a progressive screw as in a normal extruder. This progressive screw may be a first screw or a second screw.

On the downstream side of the first kneading zone, second, third,
The same kneading zone can be provided as in the ordinary extruder. In particular, when the liquid addition nozzle 5 and the side feeder 6 described below are provided, it is usual that a kneading zone is provided on the downstream side as in the conventional case. In the second and subsequent kneading zones, the reverse feed screw, the kneading light, the kneading disc (kneading left) having the blades 3 having a mutual angle of 100 to 170 degrees, the neutral, the wide, and the blade 3 having a mutual angle of 25 degrees. The kneading disc, the kneading disc (A), the kneading disc (B), the seal ring and the like having a degree of less than 100 degrees can be arbitrarily selected and used.

Further, in the present extruder 1 for powdery resin, a vent port 4, a liquid addition nozzle 5 and / or a side feeder 6 are installed on the downstream side of the first kneading zone, as in a general extruder. You can

The vent port 4 may be provided in one or more, and the direction thereof may be either upward or sideways, and may be either an atmospheric vent or a vacuum vent. At the time of liquid addition, it can be heated according to the viscosity of the liquid to be added,
Either a plunger pump or a gear pump may be used as the liquid supply pump 8 for supplying the liquid from the liquid supply tank 7. The feeders 9 and 10 are of a capacity type,
Although any of a weight type may be used, a weight type is generally preferable.

The present powdery resin extruder 1 has an apparent specific gravity of 0.2 to 0.8 and / or an average particle size of 10 to 500.
Effective for powdery resin of μm. Here, the apparent specific gravity refers to a value measured by a method shown in JIS K6911. In addition, the average particle size is large (50
In the case where the particle size is not less than 50 μm, the value is measured with a Cole counter measuring instrument according to JIS Z8801.

The type of powdery resin is not particularly limited, but specific examples include polyphenylene ether, blends of polyphenylene ether and alkenyl resin, polycarbonate, polyolefin resin (high density polyethylene, medium density polyethylene, low density polyethylene, Linear low density polyethylene, polypropylene, ethylene-propylene copolymers, etc.), homopolyoxymethylene, copolymer polyoxymethylene, polyphenylene sulphonide,
Acrylonitrile-butadiene-styrene copolymer, syndiotactic polystyrene and the like can be mentioned. The present invention is particularly effective for polyphenylene ether or a blend of polyphenylene ether and alkenyl resin. That is, since these resins have good adhesion to the metal forming the extruder and have a high extrusion temperature, they tend to produce whiskers-like deteriorated products called "Meyanii" at the spinneret, which causes strand breakage. But,
By allowing extrusion at a high extrusion rate according to the present invention, the residence time can be shortened and the occurrence of the above-mentioned "eyes" can be suppressed.

Of the above, the alkenyl resin is a homopolymer or copolymer of a vinyl aromatic compound. Examples of the vinyl aromatic compound include strain, α-methylstyrene, α-ethylstyrene, α-methylstyrene-p-methylstyrene, o-methylstyrene, m-methylstyrene and p-methylstyrene.
Each alkyl-substituted styrene such as -methylstyrene, o-chlorostyrene, m-chlorostyrene, p-chlorostyrene, p-bromostyrene, dichlorostyrene, dibromostyrene, trichlorostyrene, each halogenated styrene such as tribromostyrene, etc. Of these, styrene and α-methylstyrene are preferred.

When the above powdery resin is charged from the main hopper 2 of the powdery resin extruder 1, melted, kneaded, and extruded, the temperature of the barrel is set to the glass transition point Tg + 30 of the powdery resin. ℃ or more 350
℃ or less or melting point Tm of the powdery resin above 350 °
It is preferable to set the following. If the temperature of the barrel is too low, the molten and kneaded state of the resin tends to deteriorate, and productivity cannot be improved easily. On the contrary, if the temperature is too high, the resin tends to deteriorate.

When the powdery resin as described above is melted, kneaded and extruded by the present powdery resin extruder 1, other additional components may be added. For example, antioxidants, weather resistance improvers, nucleating agents for polyolefins, slip agents, various colorants, antistatic agents, release agents, monomer components (maleic anhydride, styrene, acrylic acid, etc.), peroxides (perhexin). 25B, perbutyl D, perhexin 25B, etc.) may be added alone or in combination of two or more.
These may be charged together with the powdery resin from the main hopper 2 or the side feeder 6.

In the present extruder for powdery resin having the side feeder 6, as the material supplied from the side feeder 6, for example, polystyrene, high-impact polystyrene, styrene-butadiene copolymer and its hydrogenated product, nylon 6, One or more resins such as nylon 66 and aromatic polyamide, talc, mica,
Examples thereof include one or more fillers such as glass beads, and one or more fillers such as glass fibers, carbon fibers, Kepler fibers, stainless fibers, and copper fibers.

In the present extruder for powdery resin having the liquid addition nozzle 5, examples of the liquid supplied from the liquid addition nozzle 5 include mineral oil, phosphoric acid ester, and silicone oil. What is mineral oil?
For example, paraffin-based, naphthene-based, aromatic-based oils and phosphates include, for example, triphenyl phosphate, 2,2-bis- {4- (bis (methylphenoxine) phosphoryloxy) phenyl} propane, and phosphoric acid. −
The silicone oil such as (3-hydroxyphenyl) diphenyl is, for example, dimethyl silicone oil, methylphenyl silicone oil, methylhydrogen silicone oil or the like, and one kind or two or more kinds can be used at the same time.

[0042]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, the first embodiment and the first comparative example will be described.
The kneading disk, forward feed screw and reverse feed screw used in the kneading zone and the second kneading zone are shown in Table 1 below.
As shown in. In the type column of Table 1, "A" is a kneading disc (A), "B" is a kneading disc (B), unmarked kneading discs other than "A" and "B", "order" ”Is a progressive screw,“ reverse ”
Means a reverse feed screw, and the fractional part of the symbol is (screw pitch) / (screw length) in mm.
Means

[0043]

[Table 1]

As the extruder, a twin-screw co-direction extruder as shown in FIG. 4 (“ZSK-40” manufactured by Warner & Freidler, L / D = 46, 11 barrels)
Based on the above, the experiment was conducted mainly by changing various screw configurations of the first kneading zone. As for the temperature of each barrel, unless otherwise noted, as shown in FIG. 4, the barrel (1) was at 50 ° C. and the barrels (2) to (5) were at 2 ° C.
The temperature was 80 ° C., and the barrels (6) to (11) were 340 ° C. Screw rotation is 295 rpm unless otherwise specified. The vent was an atmospheric vent. However, only in Example 1 and Comparative Example 2, a vacuum vent pulled by a vacuum of 50 mmHg was performed. Further, the most upstream position of the most upstream kneading disk in the first kneading zone is L / D = 8.1.

Example 1 Reduced viscosity 0.44, Tg = 220 ° C. (measured by DSC
Method), polyphenylene ether (PPE) having an apparent specific gravity of 0.694 and an average particle size of 23.1 μm was main-fed, and the extrusion amount, the presence or absence of vent up, and the presence or absence of unmelted resin in the strand were observed. The screw configuration of the first kneading zone is KR60 × 1, KR40 × 1, KR20 ×
1, KN40 × 1.

The extrusion rate was 75 kg / h. After operating for 3 hours at this extrusion rate, neither venting nor mixing of unmelted resin into the strands occurred. Also,
Even when the vent was a vacuum vent of 50 mmHg, vent up did not occur.

Comparative Example 1 The screw structure of the first kneading zone was KR60 × 1, KR4.
The same measurements and observations were carried out as in Example 1 except that 0 × 1, KR20 × 1 and KL20 × 1 were used.

The extrusion rate was 35 kg / h. When the extrusion rate exceeded 35 kg / h, a powdery resin pool was produced in the main feeder. Neither vent-up nor mixing of unmelted resin into the strands occurred.

Comparative Example 2 The screw structure of the first kneading zone was KR60 × 1, KR4.
The same measurements and observations were performed as in Example 1 except that 0 × 2 and KR20 × 1 were used.

When operated at an extrusion rate of 75 kg / h for 3 hours, the resin bent up once every 10 minutes, and unmelted resin was mixed in the strand. Further, when the vent was a vacuum vent of 50 mmHg, vent up occurred, the vent port was closed, and the extrusion rate dropped at 50 kg / h.

Comparative Example 3 The screw constitution of the first kneading zone was KR60 × 1, KR4.
The same measurements and observations were performed as in Example 1 except that 0 × 1, KN40 × 1 and KL20 × 1 were used.

The extrusion rate was 35 kg / h. When the extrusion rate exceeded 35 kg / h, a powdery resin pool was produced in the main feeder. Neither vent-up nor mixing of unmelted resin into the strands occurred.

Comparative Example 4 The screw constitution of the first kneading zone was KR60 × 1, KR4.
Similar measurements and observations were made in the same manner as in Example 1 except that 0 × 1, KR20 × 1 and KN40 × 1 were used and the barrel temperature was set to 200 ° C.

The extrusion rate was 40 kg / h. When the extrusion rate exceeded 40 kg / h, venting up and mixing of unmelted resin into the strand occurred frequently, and stable operation could not be performed.

Example 2 The screw constitution of the first kneading zone was changed to KR60 × 1 and KR4.
The same measurements and observations were made as in Example 1 except that the temperatures of the barrels (6) to (11) were set to 280 ° C., while setting to 0 × 1, KR20 × 1 and KN40 × 1.

Extrusion rate 60 kg / h (torque 60 kg / h
However, neither venting up nor mixing of the unmelted resin in the strand occurred.

Example 3 The screw constitution of the first kneading zone was changed to KR60 × 1 and KR4.
The same measurement and observation were performed as in Example 1 except that 0 × 1, KN40 × 1 and KR20 × 1 were used.

It was operated for 3 hours at an extrusion rate of 75 kg / h,
Neither venting up nor incorporation of unmelted resin into the strands occurred.

Example 4 The screw constitution of the first kneading zone was changed to KR60 × 1, KN4.
The same measurement and observation were performed as in Example 1 except that 0 × 1, KR20 × 1 and KR40 × 1 were used.

It was operated for 3 hours at an extrusion rate of 75 kg / h,
Neither venting up nor incorporation of unmelted resin into the strands occurred.

Example 5 The screw constitution of the first kneading zone was changed to KR60 × 1, KN4.
The same measurement and observation were performed as in Example 1 except that 0 × 1, KR20 × 1 and KW40 × 1 were used.

It was operated for 3 hours at an extrusion rate of 75 kg / h,
Neither venting up nor incorporation of unmelted resin into the strands occurred.

Example 6 The screw constitution of the first kneading zone was changed to KR60 × 1, KN4.
The same measurements and observations were performed as in Example 1 except that 0 × 1, KR20 × 1 and KN40 × 1 were used.

It was operated for 3 hours at an extrusion rate of 70 kg / h,
Neither venting up nor incorporation of unmelted resin into the strands occurred.

Example 7 The screw constitution of the first kneading zone was changed to KR60 × 1,60 /
The same measurements and observations were carried out as in Example 1 except that 60 × 1, KR20 × 1 and KN40 × 1 were used.

It was operated at an extrusion rate of 75 kg / h for 3 hours,
Neither venting up nor incorporation of unmelted resin into the strands occurred.

Example 8 The screw constitution of the first kneading zone was changed to KR60 × 1, KN4.
The same measurements and observations were performed as in Example 1 except that 0 × 2 and KR20 × 1 were used.

It was operated for 3 hours at an extrusion rate of 65 kg / h,
Neither venting up nor incorporation of unmelted resin into the strands occurred.

Example 9 The screw constitution of the first kneading zone was changed to KR60 × 1, KR4.
0 × 1, KR20 × 1, KN40 × 1, and a liquid addition nozzle (“CR741C” manufactured by Daiichi Kagaku Co., Ltd.) attached to the intermediate plate between the barrels (5) and (6), and the second kneading zone. Screw configuration of KR40 × 2, KR20 ×
Example 1 except 2, KN40 × 1, KL20 × 2
The same measurement and observation were performed in the same manner as described above.

PPE is 70 kg / h, liquid addition nozzle is 30
At kg / h, neither venting up nor incorporation of unmelted resin into the strand occurred.

Example 10 The screw constitution of the first kneading zone was changed to KR60 × 1 and KR4.
Example 1 except that 0x1, KR20x1, and KN40x1 were used, a side feeder was attached to the barrel (5), and high-impact polystyrene (HIPS: "Polystyrene H-433" manufactured by Asahi Kasei Corporation) was side-fed. Similar measurements and observations were made in the same manner as in.

The PPE extrusion rate was 65 kg / h (75 kg / h → 65 kg / h for torque over) and the HIPS extrusion rate was 35 kg / h, and neither vent up nor mixing of unmelted resin in the strand occurred. .

Example 11 The screw constitution of the first kneading zone was changed to KR60 × 1 and KR4.
The same measurements and observations were made in the same manner as in Example 1 except that 0 × 1, KR20 × 1 and KN40 × 1 were used and the vent was closed.

It was operated for 3 hours at an extrusion rate of 50 kg / h,
Neither venting up nor incorporation of unmelted resin into the strands occurred.

Comparative Example 5 The screw structure of the first kneading zone was KR60 × 1, KR4.
The same measurements and observations were made in the same manner as in Example 1 except that 0x1, KR20x1, and KL20x1 were used and the vent was closed.

The extrusion rate was 30 kg / h. After operating for 3 hours at this extrusion rate, neither venting nor mixing of unmelted resin into the strands occurred.

Example 12 90 parts by weight of PPE as in Example 1 and polystyrene (“Asahi Kasei Polystyrene 685” manufactured by Asahi Kasei Kogyo KK: length about 5)
(mm pellets) 10 parts by weight was blended as the main feed, and the screw constitution of the first kneading zone was KR60 × 1, KR40 × 1, KR20 × 1, KN4.
The same measurements and observations were performed as in Example 1 except that the value was 0 × 1.

After operating for 3 hours at an extrusion rate of 100 kg / h, neither venting up nor mixing of unmelted resin into the strand occurred.

Comparative Example 6 The screw constitution of the first kneading zone was changed to KR60 × 1 and KR4.
The same measurements and observations were performed as in Example 12, except that 0 × 1, KR20 × 1, and KL20 × 1 were used.

The extrusion rate was 42 kg / h. When the extrusion rate exceeded 42 kg / h, powdery resin was collected in the main feeder. Neither venting up nor incorporation of unmelted resin into the strands occurred.

Example 13 Tg = 150 ° C., apparent specific gravity 0.54, average particle size 85 μ
Polycarbonate (PC) of m was mainly fed, and the extrusion amount, the presence or absence of vent up, and the presence or absence of unmelted resin in the strand were observed in the same manner as in Example 1. Further, the screw configuration of the first kneading zone is KR60 × 1, KR40 × 1,
KR20 × 1 and KN40 × 1 are used, the vent is an atmospheric vent, and barrels (2) to (11) are 230 ° C.
And

The extrusion rate was 72 kg / h. After operating for 3 hours at this extrusion rate, neither venting nor mixing of unmelted resin into the strands occurred.

Comparative Example 7 The screw constitution of the first kneading zone was KR60 × 1, KR4.
The same measurements and observations were performed as in Example 13 except that 0 × 1, KR20 × 1, and KL20 × 1 were used.

The extrusion rate was 33 kg / h. When the extrusion rate exceeded 33 kg / h, powdery resin was collected in the main feeder. Neither venting up nor incorporation of unmelted resin into the strands occurred.

Example 14 A high-density polyethylene (HDPE) having Tm = 131 ° C. and an average particle size of 310 μm was fed as a main feed, and the extrusion amount, the presence of vent up, and the presence of unmelted resin in the strand were obtained as in Example 1. Was observed. The screw configuration of the first kneading zone is KR60 × 1, KR40 × 1, KR20 ×
1, KN 40 × 1, the vent was an atmospheric vent, and the barrels (2) to (11) were set to 180 ° C.

The extrusion rate was 97 kg / h. After operating for 3 hours at this extrusion rate, neither venting nor mixing of unmelted resin into the strands occurred.

Comparative Example 8 The screw constitution of the first kneading zone was KR60 × 1, KR4.
The same measurement and observation were performed as in Example 14 except that 0 × 1, KR20 × 1 and KL20 × 1 were used.

The extrusion rate was 60 kg / h. When the extrusion rate exceeded 60 kg / h, powdery resin was collected in the main feeder. Neither venting up nor incorporation of unmelted resin into the strands occurred.

Example 15 Homopolyoxymethylene (POM) having Tm = 162 ° C. and an average particle size of 300 μm was fed as a main feed, and the extrusion amount, the presence or absence of vent up, and the unmelted resin in the strand were measured in the same manner as in Example 1. The presence or absence was observed. The screw configuration of the first kneading zone is KR60 × 1, KR40 × 1, KR20 ×
1, KN 40 × 1, the vent was an atmospheric vent, and the barrels (2) to (11) were set to 180 ° C.

The extrusion rate was 105 kg / h. After operating for 3 hours at this extrusion rate, neither venting nor mixing of unmelted resin into the strands occurred.

Comparative Example 9 The screw constitution of the first kneading zone was KR60 × 1, KR4.
The same measurements and observations were performed as in Example 15, except that 0 × 1, KR20 × 1 and KL20 × 1 were used.

The extrusion rate was 65 kg / h. When the extrusion rate exceeded 65 kg / h, powdery resin was collected in the main feeder. Neither venting up nor incorporation of unmelted resin into the strands occurred.

Example 16 Tm = 275 ° C., apparent specific gravity 0.50, average particle size 100
Polyphenylene sulphonide (PPS) of μm was main-fed, and the extrusion amount, the presence or absence of vent up, and the presence or absence of unmelted resin in the strand were observed in the same manner as in Example 1. Further, the screw configuration of the first kneading zone is KR60 × 1, K
R40 × 1, KR20 × 1 and KN40 × 1 were used, the vent was an atmospheric vent, and barrels (2) to (11) were set to 290 ° C.

The extrusion rate was 110 kg / h. After operating for 3 hours at this extrusion rate, neither venting nor mixing of unmelted resin into the strands occurred.

Comparative Example 10 The screw constitution of the first kneading zone was KR60 × 1, KR4.
The same measurements and observations were performed as in Example 16 except that 0 × 1, KR20 × 1 and KL20 × 1 were used.

The extrusion rate was 81 kg / h. When the extrusion rate exceeded 81 kg / h, powdery resin was collected in the main feeder. Neither venting up nor incorporation of unmelted resin into the strands occurred.

Example 17 Tg = 100 ° C., 50 parts by weight of acrylonitrile / styrene copolymer (AS) having an average particle size of 35 μm, and Tg = 10.
At 0 ° C., a blended product with 50 parts by weight of an acrylonitrile-butadiene-styrene copolymer (ABS) having an average particle size of 30 μm was fed as a main feed, and the extrusion amount was the same as in Example 1.
The presence or absence of vent up and the presence or absence of unmelted resin in the strand were observed. The screw configuration of the first kneading zone is K
R60 x 1, KR40 x 1, KR20 x 1, KN40 x
1, the vent was an atmospheric vent, and the barrels (2) to (11) were set to 230 ° C.

The extrusion rate was 90 kg / h. After operating for 3 hours at this extrusion rate, neither venting nor mixing of unmelted resin into the strands occurred.

Comparative Example 11 The screw structure of the first kneading zone was KR60 × 1, KR4.
The same measurement and observation were performed as in Example 17, except that 0 × 1, KR20 × 1 and KL20 × 1 were used.

The extrusion rate was 50 kg / h. When the extrusion rate exceeded 50 kg / h, powdery resin was collected in the main feeder. Neither venting up nor incorporation of unmelted resin into the strands occurred.

Example 18 Syndiotactic polystyrene (SPS) having Tm = 270 ° C. and an average particle size of 25 μm was main-fed, and the extrusion amount, the presence or absence of vent up, and the unmelted resin in the strand were measured in the same manner as in Example 1. The presence or absence was observed. The screw configuration of the first kneading zone is KR60 × 1, KR40 × 1, KR.
20 × 1, KN 40 × 1, vents were atmospheric vents, and barrels (2) to (11) were 280 ° C.

The extrusion rate was 110 kg / h. After operating for 3 hours at this extrusion rate, neither venting nor mixing of unmelted resin into the strands occurred.

Comparative Example 12 The screw structure of the first kneading zone was KR60 × 1, KR4.
The same measurements and observations were made as in Example 18 except that 0 × 1, KR20 × 1 and KL20 × 1 were used.

The extrusion rate was 75 kg / h. When the extrusion rate exceeded 75 kg / h, powdery resin was collected in the main feeder. Neither venting up nor incorporation of unmelted resin into the strands occurred.

Comparative Example 13 The screw constitution of the first kneading zone was KR60 × 1, KR4.
The same measurement and observation were performed as in Example 1 except that 0 × 1, KR 20 × 1, and 40 / 20L were used.

The extrusion rate was 30 kg / h. After operating for 3 hours at this extrusion rate, neither venting nor mixing of unmelted resin into the strands occurred.

Examples 1 to 18 and Comparative Examples 1 to 13 described above
Table 2 and Table 3 show the outline and results.

Example 19 In the same manner as in Example 2, the extrusion rate was 35 kg / h, 48 k.
In each case of g / h and 60 kg / h, the state of occurrence of "Meyani" was observed. The results are shown below. In addition, the following evaluation is based on the number of occurrences of "Meyani", in which ◯ is 1 time / 1 hour or less, Δ is 2 to 4 times / h,
X means 5 times / h or more, and vent up and unmelted matter did not occur at any extrusion amount.

When the extrusion rate is 60 kg / h: Evaluation ○ When the extrusion rate is 48 kg / h: Evaluation Δ When the extrusion rate is 35 kg / h: Evaluation ×

From the above results, it can be seen that the extrusion rate of about 50 kg / h or more is preferable in order to suppress the occurrence of "meaya".

[0111]

[Table 2]

[0112]

[Table 3]

[0113]

Industrial Applicability The present invention is as described above, and in the powdery resin extrusion treatment, the extrusion efficiency is improved without causing troubles such as mixing of unmelted resin and vent up, and this extrusion is performed. It is possible to improve the productivity of the pellet-shaped resin or the like that is subsequently performed.

[Brief description of drawings]

FIG. 1 is an explanatory view showing an outline of an extruder for powdery resin according to the present invention.

FIG. 2 is a front view of a kneading disc (A) or (B).

FIG. 3 is a plan view of a kneading disk (A) or (B).

FIG. 4 is an explanatory diagram of an extruder used in Examples and Comparative Examples.

[Explanation of symbols]

 1 Extruder for powdery resin 2 Main hopper 3 Blade 4 Vent port 5 Liquid addition nozzle 6 Side feeder 7 Liquid addition tank 8 Liquid addition pump 9,10 Feeder

Claims (6)

[Claims] 1. A twin-screw rotary extruder, wherein the screw configuration of the first kneading zone has a dimensionless pressure gradient of 0 to −100 and a length L and a diameter when the dimensionless extrusion rate is 0.01. A kneading disc (A) having a D ratio L / D of 0.5 to 2;
An extruder for powdery resin, characterized in that the dimensionless pressure gradient when the dimensionless extrusion amount is 0.01 is larger than 0 and is configured in combination with the kneading disk (B) of 1000 or less. 2. The screw structure of the first kneading zone further comprises a progressive screw having a ratio L / D of length L to diameter D of 1.5 or less. Extruder for powdery resin. 3. An extruder for powdery resin, characterized in that the length of the screw constituent portion in claim 1 or 2 is in the range of L / D of 2-12. 4. An apparent specific gravity of 0.2 to 0.8 and / or an average particle diameter of 10 to 500 μm from the main hopper of the powdery resin extruder according to claim 1.
m powdered resin is supplied, and the barrel temperature of the extruder is set to a glass transition point Tg of this powdered resin + 30 ° C. or more 35
0 ° C or lower or melting point Tm of this powdery resin or higher 350
An extrusion method characterized by kneading and extruding at a temperature of ℃ or less. 5. The extrusion method according to claim 4, wherein the powdery resin is polyphenylene ether or a blend of polyphenylene ether and an alkenyl resin. 6. The extruder according to claim 1, wherein the uppermost stream position of the first kneading zone is L / D = 4 to 32 from the center of the main feed barrel.