WO2007007831A1

WO2007007831A1 - Breaker plate and method for granulating thermoplastic resin composition by using the same

Info

Publication number: WO2007007831A1
Application number: PCT/JP2006/313942
Authority: WO
Inventors: Kunihiro Ohuchi; Masayuki Sakka; Masachika Kotaku
Original assignee: Mitsui Chemicals, Inc.; Kawasaki Sanko Kasei Co., Ltd.
Priority date: 2005-07-14
Filing date: 2006-07-13
Publication date: 2007-01-18
Also published as: CN101218086A; JPWO2007007831A1; JP4564534B2

Abstract

A breaker plate with a specific shape, smoothly transferring resin that is plasticized and melted by a screw of an extruder. The resin is transferred to a die without adhering and staying in a resin channel from the head of the screw. As a result, carbide produced in the resin channel from the screw head to the die can be significantly reduced.

Description

Specification

Breaker plate and method for granulating thermoplastic resin composition using the same

[0001] The present invention relates to a breaker plate used by being incorporated in an extruder when granulating a thermoplastic resin composition. The present invention also relates to a method for granulating a thermoplastic resin composition in which the thermoplastic resin composition is granulated using an extruder incorporating the breaker plate.

Background art

[0002] A breaker plate that is incorporated between the tip of the screw and the die when granulating the thermoplastic resin plasticized with a screw extruder by cutting with the die force of the extruder and granulating The barrel (heating cylinder) force is used to improve the degree of resin kneading and limit pressure pulsation by restricting the flow of resin to the die, and to maintain the screen pack when using it. ing.

Conventionally, the breaker plate has a shape in which a large number of small holes through which molten resin passes are provided in a honeycomb shape on the entire surface of the breaker plate. In the conventional granulation method in which this breaker plate is incorporated into an extruder to granulate thermoplastic resin, the tip force of the screw of the extruder is supported by a resin flow path to the die, specifically by an adapter die. The molten resin adheres and stays on the wall surfaces of the upstream and downstream side of the breaker plate extruder, so that the resin deteriorates due to heat to produce carbide, and the carbide is granulated. There are defects in quality such as the wall surface force of the oil flow path peeling off and mixing into the pellets.

[0003] In addition, in order to prevent the carbide from being mixed into the granulated product, it is necessary to frequently stop the granulation operation and disassemble the equipment such as the extruder to perform cleaning, which is a problem in terms of productivity. There is also.

In order to reduce such a problem, Patent Document 1 discloses a breaker plate having a shape in which holes through which the molten resin passes are radially inclined in order to reduce the retention of the molten resin in the resin flow path. Further, Patent Document 2 discloses a breaker plate having a shape in which an end surface facing a screw front end surface is parallel. Such a break Even for car plates, there is a problem that granulation of thermoplastic resin cannot obtain a sufficient effect, especially with a high melting point such as engineering plastics and a high molding temperature.

Patent Document 1: JP-A-10-119116

Patent Document 2: JP-A-9 29816

Disclosure of the invention

Problems to be solved by the invention

[0004] The present invention has been made in view of such a situation, and stayed by adhering to the wall surfaces of the oil passages on the upstream side and the downstream side of the extruder of the breaker plate supported by the adapter die. The resin deteriorates due to heat to generate carbides, which reduces the trouble that the carbides are peeled off from the wall surface of the resin flow channel and mixed into the granulated product, and the carbides to the granulated product An object of the present invention is to provide a breaker plate for an extruder that prevents a reduction in production efficiency due to disassembly and cleaning of the extruder to prevent mixing.

Means for solving the problem

[0005] As a result of intensive studies to achieve the above object, the present inventors have incorporated a breaker plate having a specific shape into an extruder and used it with a screw of a heating and extrusion machine. The plasticized and melted resin can smoothly move to the die without sticking to the resin flow path between the screw tip end of the extruder and staying at the die. The inventors have found that the carbide at the tip of the screw, which is a problem in the breaker plate, can be extremely reduced in carbides generated in the oil flow path between the die and the present invention.

[0006] That is, the breaker plate according to the present invention comprises:

Breaker plate with small holes that are arranged in the resin flow passage on the outlet side of the screw shaft of the screw extruder for extruding the thermoplastic resin composition and penetrate from the upstream side to the downstream side of the extruder Because

A small hole is present in the outer peripheral portion of the breaker plate, and a protrusion is provided at the center of the downstream surface of the breaker plate extruder.

[0007] In addition, the present invention provides a center of the cross section of a resin flow path in which a small-pore force breaker plate that passes from the upstream side to the downstream side of the extruder existing on the outer periphery of the breaker plate is disposed. The distance from the center to the wall surface of the resin flow channel is preferably set at a position of 0.2 to 1, starting from.

[0008] Furthermore, the breaker plate of the present invention preferably has a protrusion at the center of the upstream surface in the extruder of the breaker plate disposed in the resin flow path.

In addition, the granulation method of the thermoplastic rosin composition according to the present invention,

The above-described breaker plate is disposed in the resin flow path on the outlet side of the screw shaft tip of the screw extruder, and the plasticized thermoplastic resin composition flowing on the upstream side of the screw extruder A step of transferring the product to the outer peripheral portion of the breaker plate by a protrusion disposed in the center of the upstream surface of the breaker plate extruder, and the thermoplastic resin composition transferred to the outer peripheral portion of the outer periphery of the breaker plate Passing through the small holes arranged in the section and moving to the downstream side of the breaker plate extruder,

The thermoplastic resin composition that has passed through the small holes is connected to the downstream resin flow path by a protrusion disposed in the center of the downstream surface of the breaker plate extruder. And a step of cutting the extruded thermoplastic resin composition from the small hole cap arranged on the die.

[0009] Here, it is preferable that the thermoplastic resin composition contains a thermoplastic resin having a melting point of 200 to 400 ° C.

Further, it is preferable that the thermoplastic resin contained in the thermoplastic resin composition is at least one selected from polyamide, polyester, polyphenylene sulfide, and liquid crystalline polymer strength.

[ooio] Furthermore, it is preferred that the thermoplastic resin composition comprises a fibrous reinforcement and Z or a flame retardant! /.

The invention's effect

[0011] By using the breaker plate of the present invention, it is possible to remarkably reduce the carbide generated in the resin flow path to the die as well as the screw tip force of the extruder, and by the separation of the adhering carbide from the resin flow path. The quality of the granulated product can be improved because the contamination in the granulated product can be greatly reduced. In addition, the frequency of cleaning by disassembling the extruder can be reduced, enabling continuous production over a long period of time, which is extremely valuable industrially. [0012] Further, according to the granulation method of the thermoplastic resin composition using the breaker plate, an industrially preferable granulated product can be produced.

Brief Description of Drawings

FIG. 1 is a cross-sectional view of the periphery of an adapter die of an extruder incorporating a breaker plate.

[FIG. 2] FIG. 2 is a cross-sectional view of the periphery of the adapter die shown in FIG. 1 in a direction different from FIG. 1 by 90 °.

[FIG. 3] FIG. 3 is a side view of the breaker plate as viewed from the direction of the line AA in FIG.

[FIG. 4] FIG. 4 is a side view of the breaker plate as viewed from the direction of the line BB in FIG.

FIG. 5 is a front view of a breaker plate incorporated in the extruder shown in FIG.

Explanation of symbols

[0014] 1 screw extruder

2 Screw shaft

3 Breaker plate

3a Small hole in breaker plate

3b Projection on the downstream breaker plate surface of the extruder

3c Projection on the upstream breaker plate surface of the extruder

4 Adapter dice

5 Oil flow path on the downstream side of the breaker plate extruder

6 Oil flow path upstream of the breaker plate extruder

7 Dice

7a Small hole in the die

BEST MODE FOR CARRYING OUT THE INVENTION

[0015] The granulation method of the thermoplastic resin composition using the breaker plate according to the present invention and an extruder incorporating the breaker plate will be described below.

[Breaker plate of the present invention] Fig. 1 is a sectional view of the periphery of an adapter die in an extruder incorporating a breaker plate according to an embodiment of the present invention, and Fig. 2 is 90 ° different from Fig. 1 of the periphery of the adapter die shown in Fig. 1. Fig. 3 is a side view of the breaker plate when viewed from the direction A-A in Fig. 2, and Fig. 4 is a side view of the breaker plate when viewed in the direction of the line B-B in Fig. 2. Figures 5 and 5 are front views of the breaker plate incorporated in the extruder shown in FIG.

In the figure, 1 is a screw extruder, 2 is a screw shaft, 3 is a breaker plate, 4 is an adapter die, 5 is a grease flow path from the downstream side of the breaker plate extruder to the die, 6 is a screw on screw shaft 2 A grease flow path from the end of the element to the upstream side of the extruder of the breaker plate 3, 3a is a small hole arranged on the outer periphery of the breaker plate, 3b is a protrusion at the center of the breaker plate surface on the downstream side of the extruder 3c is a protrusion at the center of the breaker plate surface on the upstream side of the extruder, 7 is a die, and 7a is a small hole arranged in the die.

The breaker plate 3 of the present invention is arranged in the resin flow path on the outlet side from the tip of the screw shaft 2 of the screw extruder 1 for extruding the thermoplastic resin composition, and the breaker plate extruder in which the breaker plate 3 is arranged In the oil flow passage 6 on the upstream side, the center of the cross section of the resin flow passage 6 closest to the breaker plate 3 is set as a starting point (the cross-sectional center position of the resin flow passage 6 is set to 0). When the distance from the central wall to the outer circumferential wall surface of the resin flow path 6 is 1, it is 0.2 to 1, preferably 0.4 to 1, and further to the outer periphery of the breaker plate 3 of 0.5 to 1. A small hole 3a penetrating from the upstream side to the downstream side of the extruder is provided.

The number of small holes 3a provided in the breaker plate 3 is 2 to 40, preferably 4 to 30, more preferably 6 to 20, depending on the type of resin to be granulated and the size of the extruder. In addition, the aperture ratio of the small holes is set to have sufficient strength against the assumed melted resin pressure and the pressure-receiving area force of the breaker plate. It is preferable. If the aperture ratio of the small holes is reduced, sufficient strength can be easily obtained, and if the aperture ratio of the small holes is increased, the portion perpendicular to the flow direction in which the molten resin stays and adheres is reduced, and a sufficient discharge amount is easy. Is obtained. In addition, the distance between the small holes on the upstream surface of the extruder is as small as possible in the plane perpendicular to the flow direction of the resin. It is preferable to gradually increase from the upstream side to the downstream side so as to become larger. Further, it is preferable that the small hole 3a is directed from the upstream side to the downstream side so that the size of the hole gradually decreases.

[0017] Furthermore, a protrusion 3b is arranged on the center of the downstream surface of the breaker plate 3 extruder of the present invention, that is, on the surface on the center side of the breaker plate from the small hole 3a. 3b does not have a small hole 3a penetrating from the upstream side to the downstream side of the extruder

[0018] The shape of the protrusion 3b provided at the center of the downstream surface of the breaker plate 3 in the extruder follows the internal shape of the adapter die 4, and the surface force of the breaker on the downstream side of the extruder is equal to that of the die. It is formed so as to gradually become smaller in the direction of direction 7, for example, a conical shape or a shape shown in FIGS. 3 and 5. Further, the size of the protrusion 3b is such that the volume occupied by the protrusion 3b is 0.1 to 0.6, preferably assuming that the downstream flow from the breaker plate 3 and the volume of the resin flow path 5 to the die 7 is 1. Is preferably 0.1 to 0.5, more preferably 0.2 to 0.4.

[0019] By using the breaker plate 3 of the present invention having the small holes 3a at specific positions on the outer peripheral portion as described above for granulation of the thermoplastic resin composition, the screw tip cover and other dies 7 Residue of the molten resin in the resin flow path up to this can be reduced, and thermal deterioration of the resin can be prevented.

[0020] In addition to the above structure, the breaker plate 3 of the present invention further includes a central portion of the upstream surface in the extruder of the breaker plate 3, that is, the center side of the breaker plate from the small hole 3a. It is preferable to have a protrusion 3c on the surface. Further, it is preferable that the protrusion 3c does not have a small hole 3a penetrating from the upstream side to the downstream side of the extruder.

[0021] The shape of the protrusion 3c provided in the central portion of the upstream surface of the breaker plate 3 extruder is such that the molten resin that has also been transported by the screw groove force exits from the tip of the screw shaft 2 and is lubricated. Upstream of the extruder along the internal shape of the oil flow channel 6, which is preferably formed to travel the shortest distance, i.e., as linear as possible, to the small hole 3 a of the breaker plate It is preferable to form it so that it gradually decreases from the breaker plate surface on the side toward the tip of the screw shaft 2, for example, a conical shape, FIG. 4 and FIG. 5. The shape represented by is mentioned.

Further, the size of the protrusion 3c is such that the terminal element of the screw element of the screw shaft 2 is also removed from the oil passage 6 to the upstream side of the extruder of the breaker plate 3 except for the volume occupied by the screw shaft 2. When the volume of the flow path is 1, it is preferable that the volume of the protrusions is 0 to 0.2.

[0022] In particular, when granulation is performed by blending a reinforcing material such as glass fiber without incorporating a screen pack into the extruder, a protrusion 3c is formed at the center of the breaker plate surface on the upstream side of the extruder. Is preferably arranged. In this way, it is possible to more effectively prevent the degradation of the resin from adhering to the wall surface of the upstream resin channel 6 in the extruder of the breaker plate 3.

[Thermoplastic resin composition]

The breaker plate 3 of the present invention can be used by being arranged in the resin flow path on the outlet side from the tip of the screw shaft of the screw extruder when granulating the thermoplastic resin composition. As a product, addition of reinforcing agents, flame retardants, lubricants, antiblocking agents, antifoaming agents, pigments, dyes, nucleating agents, plasticizers, thickeners, heat stabilizers, weathering stabilizers, etc. What mix | blended the agent can be used conveniently.

[0023] For example, examples of the reinforcing agent used by adding to the thermoplastic resin composition include reinforcing agents having various shapes such as fibrous, powdery, plate-like, needle-like, cloth-like, and mat-like. However, inorganic fibers such as glass fiber, potassium titanate fiber, metal-coated glass fiber, ceramic fiber, wollastonite, carbon fiber, metal carbide fiber, and metal-cured fiber are preferred for fibrous reinforcing agents. Fibers or organic fibers are used. The surface of these fibrous fillers may be surface treated with a silane compound or the like. Among these, inorganic fibers, particularly glass fibers are preferable from the viewpoint of heat resistance. Depending on the type and purpose of the thermoplastic resin used, the addition amount of the reinforcing agent is 0.01-400 parts by mass, preferably 0.1-200 parts by mass, with respect to 100 parts by mass of the thermoplastic resin. By doing so, the rigidity and heat resistance of the thermoplastic resin can be improved satisfactorily.

[0024] Further, as the flame retardant, an organic flame retardant and an inorganic flame retardant can be used as long as the flame retardant can be imparted to the resin. Organic flame retardants include brominated flame retardants, salts Preferred inorganic flame retardants such as elemental flame retardants, phosphorus flame retardants, and nitrogen flame retardants are hydrated metal compounds, metal compounds, metal oxides, and the like.

[0025] Further, flame retardant aids that may be used in combination with brominated flame retardants or chlorinated flame retardants include antimony compounds such as acid antimony and sodium antimonate. Metal oxides such as magnesium oxide, metal borates such as zinc borate, zinc compounds such as zinc oxide, zinc stannate and zinc phosphate, molybdenum compounds, and the like. Sodium antimonate and zinc borate are preferred. Although depending on the type and purpose of the thermoplastic resin used, the amount of the flame retardant added is 10 to 200 parts by mass, preferably 20 to: LOO parts by mass with respect to 100 parts by mass of the thermoplastic resin. When added, good flame retardancy can be obtained. Furthermore, you may use an anti-drip agent etc. together with these flame retardants.

[0026] The additives mentioned above can be selected depending on the purpose, and can be used within the range without impairing the object of the present invention.

[Thermoplastic resin]

The thermoplastic resin contained in the thermoplastic resin composition is not limited as long as it is plastic resin that is plasticized by the application of shearing heat or heat. For example, polyethylene, polypropylene, ethylene vinyl acetate copolymer Polyolefin resin such as coalescence, polyvinyl chloride, polyvinyl chloride-polyene, acrylonitrile styrene copolymer, polystyrene, (meth) acrylic resin, polyamide, polycarbonate, polyacetal, polybulal alcohol, thermoplastic polyester These include thermoplastic elastomers, polyphenylene sulfide, liquid crystal polymers, and the like. These resins may be used alone or in combination of two or more.

[0027] Among these, the extruder incorporating the breaker plate of the present invention is particularly suitable for granulation of thermoplastic resin having a high melting point and a high molding temperature such as engineering plastics. As the thermoplastic resin having a high melting point, a thermoplastic resin having a melting point of 200 to 450 ° C, preferably 210 to 400 ° C, more preferably 220 to 350 ° C, specifically, Polyamide, polyester, polyphenylene sulfide, liquid crystal polymer is preferred, but polyamide is preferred as polyamide 6, polyamide 66, polyamide 12, aliphatic polyamide such as polyamide 612, polyamide 46, etc. , Polyamide 6T, polyamide 61, polyamide 9Τ, polyamide 10Τ, semi-aromatic polyamide such as polyamide MXD6 and their copolymerization The body can be mentioned.

[Granulation method of the thermoplastic resin composition of the present invention]

The extruder used for the granulation of the thermoplastic resin composition of the present invention is an extruder having a single screw, two or more screws, or a combination of these. It can be either the opposite or the same axis, but it can also be a mold, a mold, a non-match, or a mold. In addition, the shaft shape can be either a parallel type or a coral type, and a tandem system in which a single screw extruder is combined in multiple stages is also acceptable. The composition can be granulated.

Specifically, powdered, pelletized, thermoplastic resin obtained by pulverizing solidified resin once melted, and stabilizers, fillers, flame retardants, pigments, etc. are added to the Henschel mixer according to the purpose. After mixing using a tumbler, a blender, etc., the mixture is supplied to a screw extruder 1 incorporating a breaker plate 3 having a specific structure of the present invention. The thermoplastic resin heated by the extruder 1 and plasticized by the screw shaft 2 moves to the screw tip by the rotation of the screw shaft 2 of the extruder, and passes through the resin flow path 6 to the breaker plate 3 of the present invention. By passing through the small hole 3a arranged in the outer peripheral portion, the resin passage ₅ is moved downstream of the breaker plate ₃ along the outer peripheral portion of the resin flow passage ₆ . Next, the extruded product is extruded from a small hole 7a of a die arranged in a die 7 connected to the resin flow path 5, and is cut with a cutter to obtain a granulated product of the thermoplastic resin composition.

[Example]

Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited thereto.

[Breaker plate of the present invention]

A breaker plate having the shape shown in FIGS. 3 to 5 was used.

A breaker plate having a shape in which a small hole 3a is provided on the outer peripheral portion of the breaker plate surface, and protrusions 3b and 3c are arranged on both sides closer to the center than the small hole 3a of the breaker plate. The position of the small hole 3a on the upstream side of the machine is 0.5 to 1.0 starting from the center of the resin flow path 6, and the position of the small hole 3a on the downstream side of the extruder is the center of the resin flow path 5. From 0.6 to 1.0, opening rate of breaker plate 3 20%, under breaker plate 3 As for the flow side force, the volume occupied by the protrusion 3b is 0.3 when the volume of the resin flow path 5 up to the die 8 is 1, and the terminal force of the measuring part of the screw shaft 2 is also upstream of the extruder of the breaker plate 3. The volume of the protrusion 3c is 0.04 when the volume of the grease channel excluding the volume occupied by the screw shaft from the grease channel 6 to the side surface is 1.

[Evaluation of the number of granules containing black carbide]

5 kg of the pellets were spread on a white decora plate and visually observed for 10 minutes, and the number of pellets containing black foreign matters having a diameter of 0.6 mm or more was measured.

[Example 1]

To the raw material hopper of the twin-screw extruder (Werner & Pfleiderer ZSK 58) equipped with the breaker plate of the present invention, modified polyamide 6T (extreme viscosity 1. Odl / g, melting point 320 ° C) 42 parts by weight , Brominated flame retardant 24 parts by mass, sodium antimonate 4 parts by mass, a mixture containing 30 parts by mass of side feeders and glass fiber reinforced flame retardant The product is granulated at a discharge rate of 250 kgZ hours, immediately after the start of granulation, at the time of 1 ton production, 2 ton production and 3 ton production, 5 kg of granulated pellets are used. The obtained granulated pellets were spread and observed visually for 10 minutes, and the number of granulated pellets containing black carbide due to deterioration of the resin was measured. The evaluation results are shown in Table 1.

In addition, after producing 3 tons of the resin composition, the inside of the twin-screw extruder is purged with polystyrene having a molecular weight of 240,000 to 260,000, and then the adapter die supporting the breaker plate is opened and the resin flow path is opened. When the inside was visually confirmed, a very small amount of carbide was confirmed on the wall of the adapter die located upstream of the extruder against the breaker plate supported by the adapter die. Downstream adapter die Carbide was not observed on the wall.

[Comparative Example 1]

Except for using a breaker plate that has been commonly used in the past, with a small hole penetrating from the upstream side to the downstream side of the extruder concentrically around the central axis. Granules were produced in the same manner as in Example 1, and the number of granules containing black carbide due to deterioration of the resin was measured. Table 1 shows the evaluation results. [0030] Further, after purging the inside of the extruder as in Example 1, the adapter die supporting the breaker plate was opened and the inside of the resin flow path was visually confirmed. As a result, the adapter die was supported. 10-20mm black carbide adhered to the entire circumferential wall surface of the adapter die located upstream of the extruder against the breaker plate. In addition, black carbide with a thickness of 5 to: LOmm was also attached to the entire circumferential wall of the adapter die on the downstream side.

[0031] [Table 1]

Industrial applicability

[0032] The breaker plate having a specific structure of the present invention has a high-melting point, particularly high-melting-point resin, and the upstream and downstream sides of the breaker plate. Resin adheres and stays in the flow path, and it is possible to prevent the carbide generated by the thermal deterioration of the retained resin from being separated from the resin flow path and mixed into the pellet. Furthermore, the frequency of disassembly and cleaning of equipment such as extruders can be reduced, and this is extremely industrially valuable.

Claims

The scope of the claims

[1] A small hole is provided in the resin flow path on the outlet side from the tip of the screw shaft of the screw extruder for extruding the thermoplastic resin composition and penetrates from the upstream side to the downstream side of the extruder. Breaker plate,

A breaker plate characterized in that a small hole is present in the outer peripheral portion of the breaker plate, and a protrusion is provided at the center of the downstream surface of the breaker plate extruder.

[2] A small hole penetrating from the upstream side to the downstream side of the extruder on the outer periphery of the breaker plate starts from the center of the cross-section of the resin flow path where the breaker plate is arranged. 2. The breaker plate according to claim 1, wherein the breaker plate is located at a position of 0.2 to 1 when the distance to the wall surface of the oil flow path is 1.

[3] The breaker plate according to claim 1 or 2, wherein the breaker plate has a protrusion at the center of the upstream surface of the breaker plate extruder disposed in the resin flow path.

[4] The breaker plate according to any one of claims 1 to 3 is arranged in the oil passage on the outlet side of the screw shaft of the screw extruder, and flows on the upstream side of the screw extruder. Transferring the plasticized thermoplastic resin composition to the outer periphery of the breaker plate by a protrusion disposed in the center of the upstream surface of the breaker plate extruder,

The thermoplastic resin composition that has moved to the outer peripheral portion passes through the small holes disposed on the outer peripheral portion of the breaker plate and moves to the downstream side of the breaker plate extruder, and the thermoplastic resin that has passed through the small holes. The oil composition is led to a die connected to the downstream oil flow path by a protrusion disposed at the center of the downstream surface of the breaker plate extruder, and a small hole disposed in the die. A granulation method of a thermoplastic resin composition, comprising a step of cutting the extruded thermoplastic resin composition.

[5] A thermoplastic resin composition is

5. The method for granulating a thermoplastic resin composition according to claim 4, comprising a thermoplastic resin having a melting point of 200 to 400 ° C.

[6] The thermoplastic resin contained in the thermoplastic resin composition is

6. The method for granulating a thermoplastic resin composition according to claim 4 or 5, wherein at least one selected from polyamide, polyester, polyphenylene sulfide and liquid crystalline polymer strength is used.

[7] A thermoplastic resin composition is

The method for granulating a thermoplastic resin composition according to any one of claims 4 to 6, comprising a fibrous reinforcing material and Z or a flame retardant.