JP2017113926A - Breaker plate for extruder, extruder and manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a breaker plate for extruder capable of further suppressing residence of a resin composition.SOLUTION: A breaker plate 1 has a plurality of pores 2 penetrating from one surface 1A toward another surface 1B, a boundary 3 dividing neighboring pores 2 has a taper shape from one surface 1A toward another surface 1B and height of a first boundary 3A with a first direction (X direction) as a longer direction (length of a Z direction) and height of a second boundary 3B with a second direction (Y direction) as the longer direction are different. The breaker plate 1 is suitable for applications for obtaining a polyacetal resin composition from an outlet of a screw extruder by supplying a polyacetal resin, thermoplastic polyurethane of 1 pt.wt. to 60 pts.wt. based on the polyacetal resin and a polyvalent isocyanate compound of 1 pt.wt. to 10 pts.wt. based on the polyacetal resin to an inlet of the extruder.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a breaker plate for an extruder, an extruder, and a method for producing a polyacetal resin composition.

  FIG. 4 is an example showing a general extruder 10. The extruder 10 includes an inlet 20 for supplying the resin raw material, a flow path 30 through which the resin raw material passes, a screw 40 for extruding the resin raw material inside the flow path 30 while plasticizing the resin raw material, and an outlet side from the tip 41 of the screw. In order to remove various foreign substances contained in the plasticized resin composition, the breaker plate 50 provided with a screen (not shown) on the upstream side and the plasticized resin composition are discharged. And an outlet (not shown).

  FIG. 5 is a schematic diagram showing an example of a commonly used breaker plate 50. The breaker plate 50 has a hole 51 penetrating from one surface 50A toward the other surface 50B. A plurality of holes 51 are provided via the boundary portion 52.

  However, as shown in FIG. 6, the breaker plate 50 is arranged so that one surface 50A of the breaker plate 50 is on the inlet 20 side of the extruder 10 and the other surface 50B is on the outlet side, and the resin raw material is fed into the inlet 20. When the extruder 10 is operated by being supplied to, the resin composition stays on the other surface 50 </ b> B of the breaker plate 50, particularly on the back surface of the boundary portion 52.

  FIG. 7 is a schematic diagram showing a state of the other surface 50B in the region R ′ of the breaker plate 50 after a predetermined time has elapsed since the operation of the extruder 10. When the resin composition continues to stay on the back surface of the boundary portion 52, the resin composition is carbonized with the passage of time and becomes solid carbide C. Then, as the solid carbide C continues to accumulate, the carbide C blocks the periphery of the hole 51. Carbide C is not preferable because it can be a foreign substance to the resin composition and can hinder the fluidity of the plasticized resin composition.

  Therefore, at the production site of the resin composition, the hue of the resin composition discharged from the outlet of the extruder 10 is confirmed. When a change in hue is recognized, the operation of the extruder 10 is stopped and the inside of the extruder 10 is stopped. Is disassembled and cleaned. However, since disassembly cleaning leads to a decrease in the operation rate and an increase in product cost, it is preferable to minimize the frequency of disassembly cleaning.

  Various breaker plates have been proposed in order to prevent the resin composition from staying on the back surface of the boundary portion 52. For example, in the vicinity of the end surface of the breaker plate, an expanded portion with a gradually increasing diameter is provided toward the end surface, and the cross-sectional shape V-shaped or U-shaped along each concentric circle of the metal disk In addition, the gap at the bottom of the groove between the adjacent enlarged hole portions and the enlarged hole portion and the gap at the end surface of the adjacent groove and the groove are each equal to or less than 2 mm on the same circumference. Has been proposed (see Patent Document 1).

  In addition, it has been proposed to provide a tapered protrusion at the center of both surfaces of the plate-like body and provide a plurality of through holes in the plate-like body around the protrusion (see Patent Document 2).

  Further, it has been proposed that a hole through which a material passes is inclined radially from the inlet to the outlet toward the outer periphery, and a protrusion is provided at the center of the outlet (see Patent Document 3).

  Further, it has been proposed to arrange the holes provided closer to the outer edge of the breaker plate so as to have a larger diameter than the holes provided closer to the center of the breaker plate (Patent Document 4). reference).

  Further, it has been proposed that a small hole exists in the outer peripheral portion of the breaker plate, and that a protrusion is provided at the center of the downstream surface of the breaker plate extruder (see Patent Document 5).

JP-A-6-315967 Japanese Utility Model Publication No. 7-015323 Japanese Patent Laid-Open No. 10-119116 JP 2006-312242 A International Publication No. 2007/007831 Pamphlet

  However, when the target resin is a thermoplastic resin having a high melting point and a high molding temperature such as engineering plastics, carbonization of the resin staying on the back surface of the breaker plate proceeds in a short time. Improvement is required.

  By the way, for the purpose of having high toughness, it is required to provide a polyacetal resin composition containing thermoplastic polyurethane. However, because the polarity of thermoplastic polyurethane is higher than that of polyacetal resin, thermoplastic polyurethane tends to stick to metal materials compared to polyacetal resin, and as the operating time of the extruder passes, It has the property of being selectively carbonized. For this reason, when the thermoplastic resin composition to be dealt with is a polyacetal resin composition containing thermoplastic polyurethane, further improvement for retention prevention is required.

  An object of this invention is to provide the breaker plate for extruders which can suppress the residence of a resin composition much less.

  As a result of intensive studies to achieve the above-mentioned problems, the present inventor made the boundary part separating adjacent holes into a tapered shape and the first direction which is an arbitrary direction parallel to one surface and the other surface. The height of the boundary portion that is the longitudinal direction and the height of the boundary portion that is parallel to the one surface and the other surface and that has the second direction that is another direction different from the first direction as the longitudinal direction It was found that the above-mentioned object can be achieved by differentiating and the present invention has been completed. More specifically, the present invention provides the following.

  (1) The present invention has a plurality of holes penetrating from one surface to the other surface, and a boundary portion separating adjacent holes is tapered from the one surface to the other surface. Yes, any one direction parallel to the one surface and the other surface is defined as the first direction, and the other one direction different from the first direction is parallel to the one surface and the other surface. When the second direction and the direction from the one surface to the other surface is the height direction, the height of the boundary portion having the first direction as the longitudinal direction and the second direction as the longitudinal direction It is a breaker plate for extruders in which the height of the said boundary part differs.

  (2) Moreover, this invention is a part breaker plate for extruders as described in (1) whose shape of the said hole is substantially square shape.

  (3) Moreover, this invention is a breaker for extruders as described in (2) whose said substantially square shape is substantially rectangular shape or substantially square shape, and whose said 1st direction and said 2nd direction are substantially perpendicular | vertical. It is a plate.

  (4) Moreover, this invention is equipped with a screw and the breaker plate for extruders in any one of (1) to (3), The said breaker plate for extruders is an exit side rather than the front-end | tip of the said screw. In the flow path, the extruder is disposed such that the one surface is on the inlet side and the other surface is on the outlet side.

  (5) Further, the present invention provides a polyacetal resin, 1 to 60 parts by weight of thermoplastic polyurethane with respect to the polyacetal resin, and the polyacetal resin at the inlet of the extruder according to (4). 1 part by weight or more and 10 parts by weight or less of a polyvalent isocyanate compound is supplied to obtain a polyacetal resin composition from the outlet of the screw extruder.

  The breaker plate for an extruder according to the present invention has a plurality of holes penetrating from one surface to the other surface, and a boundary portion separating adjacent holes is directed from the one surface to the other surface. Taper. The extruder breaker plate is arranged so that the one surface is on the inlet side and the other surface is on the outlet side in the flow path on the outlet side of the tip of the screw in the extruder. And a raw material is supplied to the inlet_port | entrance of an extruder and an extruder is operated. When the resin composition that passes through the flow path of the extruder passes through the holes of the breaker plate, it forms a tapered flow that is the shape of the boundary that separates adjacent holes from the inlet side toward the outlet side. Therefore, it is possible to prevent the resin composition from staying on the back surface of the boundary portion.

  Also, any one direction parallel to one surface of the breaker plate (surface on the inlet side of the extruder) and the other surface (surface on the outlet side of the extruder) is defined as the first direction, and the surface on the inlet side and the surface on the outlet side , A second direction that is different from the first direction is the second direction, and a direction from the inlet side surface to the outlet side surface is the height direction. The height of the portion is different from the height of the boundary portion whose longitudinal direction is the second direction. Therefore, when the resin composition passes through the holes of the breaker plate, the flow of the resin composition can be disturbed on the back surface of the breaker plate, and as a result, the resin composition is agitated. Therefore, it is possible to further prevent the resin composition from staying on the back surface of the boundary portion.

  Therefore, according to this invention, the breaker plate for extruders which can suppress the residence of a resin composition still more less can be provided.

It is a schematic plan view which shows an example of the breaker plate 1 for extruders of this embodiment. It is a schematic diagram which shows the relationship between the hole 2 and the boundary part 3 in the area | region R of FIG. It is a schematic diagram which shows the flow of the resin composition when operating an extruder using the breaker plate 1 of this embodiment. 1 is a schematic diagram illustrating an example of a general extruder 10. It is a schematic diagram which shows an example of the breaker plate 50 used widely. It is a schematic diagram which shows the flow of the resin composition when operating the extruder 10 using the breaker plate 50 used widely. It is the schematic which shows the state of the other surface 50B in area | region R 'of FIG. 5 after predetermined time passes, after operating the extruder 10. FIG.

  Hereinafter, specific embodiments of the present invention will be described in detail. However, the present invention is not limited to the following embodiments, and may be implemented with appropriate modifications within the scope of the object of the present invention. can do.

<Breaker plate for extruder>
FIG. 1 is a schematic plan view showing an example of the breaker plate 1 for an extruder according to the present embodiment. The breaker plate 1 has a hole 2 penetrating from one surface 1A to the other surface 1B. A plurality of holes 2 are provided via the boundary 3.

  The material of the breaker plate 1 is not particularly limited as long as it does not deform at a temperature at which the target resin composition can be melt-kneaded. For example, SUS440C, SUS420J2, etc. are mentioned.

  The number of holes 2 depends on the type of resin to be granulated and the size of the extruder, but is preferably 2 to 40, preferably 4 to 30, more preferably 6 to 20, and the aperture ratio of the small holes is It is preferably set so as to have sufficient strength against the resin pressure received by the breaker plate calculated from the assumed molten resin pressure and the pressure receiving area of the breaker plate. If the aperture ratio of the hole 2 is reduced, sufficient strength can be easily obtained, and if the aperture ratio of the hole 2 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.

  FIG. 2 is a schematic diagram showing the relationship between the hole 2 and the boundary portion 3 in the region R of the breaker plate 1. The boundary part 3 (generic name for 3A and 3B) is tapered from one surface 1A to the other surface 1B.

  The tapered shape is not particularly limited as long as it is tapered from one surface 1A to the other surface 1B. The magnitude of the taper angle θ is not particularly limited, but is preferably 30 degrees or more and 90 degrees or less, and more preferably 45 degrees or more and 70 degrees or less. If the taper angle θ is too small, it may be damaged. When the taper angle θ is too large, it is not possible to sufficiently obtain the resin composition retention suppressing effect, the operating time of the extruder elapses, and the resin composition is carbonized on the other surface 1B of the breaker plate 1, Solid carbides can accumulate. As solid carbide continues to accumulate, the carbide plugs the periphery of the hole 2. The carbide can be a foreign substance for the resin composition and can hinder the fluidity of the plasticized resin composition.

  Further, an arbitrary one direction parallel to one surface 1A and the other surface 1B is defined as a first direction (X direction), which is parallel to one surface 1A and the other surface 1B, and is different from the first direction. When one direction is the second direction (Y direction) and the direction from one surface 1A to the other surface 1B is the height direction (Z direction), the first boundary 3A has the first direction as the longitudinal direction. The height is different from the height of the second boundary portion 3B having the second direction as the longitudinal direction. When the resin composition passes through the holes 2 of the breaker plate 1 due to the difference in height between the first boundary portion 3A and the second boundary portion 3B, the resin on the outlet side in the traveling direction of the resin composition in the flow path of the extruder The flow of the composition can be disturbed, and as a result, the resin composition is agitated. Therefore, it is possible to further prevent the resin composition from staying on the back surface of the boundary portion.

  The first boundary portion 3A and the second boundary portion 3B are not particularly limited as long as they have different heights. The first boundary portion 3A may be higher than the second boundary portion 3B, and the second boundary portion 3B may be higher than the first boundary portion 3A.

Of the first boundary portion 3A and the second boundary portion 3B, lower the ratio to the height _{H High} the higher boundary of height _{H Low} boundary portion _{(H Low /} H _High) is 0.3 or more It is preferably 0.9 or less, and more preferably 0.5 or more and 0.8 or less. Breaker plate in which, when H _Low / H _High is too small, the lower boundary part of the first boundary part 3A and the second boundary part 3B removes various foreign substances contained in the plasticized resin composition. 1 There is a possibility that the original function cannot be exhibited. If H _Low / H _High is too large, the flow of the resin composition cannot be disturbed on the outlet side of the resin composition in the flow path of the extruder, and the resin composition stays behind the boundary portion. As a result, as the operation time of the extruder elapses, the resin composition is carbonized on the other surface 1B of the breaker plate 1, and solid carbide can be accumulated.

  The shape of the hole 2 is not particularly limited. Examples of the shape of the hole 2 include a substantially square shape, a substantially hexagonal shape, and a substantially circular shape. Among them, the difference between the height of the first boundary portion 3A and the second boundary portion 3B is caused, and the flow of the resin composition in the flow direction of the resin composition in the flow path of the extruder tends to be disturbed, The shape of the hole 2 is preferably a substantially square shape. Moreover, the shape of the hole 2 is a substantially rectangular shape or a substantially square shape, and it is more preferable that the first direction and the second direction are substantially vertical.

<Extruder>
The extruder of the present embodiment is the same as the conventionally known extruder 10 described in FIG. 4 except that the shape of the breaker plate is the breaker plate 1 described above. An extruder 10 shown in FIG. 4 includes a screw 40 uniaxially, biaxially or more, or a combination thereof, and a breaker plate 1. At that time, the breaker plate 1 is such that one surface 1A is on the inlet side of the extruder 10 and the other surface 1B is on the outlet side of the extruder 10 in the flow path 30 on the outlet side of the tip 41 of the screw 40. Placed in.

  In the case of two shafts, the rotation directions of the screws may be opposite or the same in each shaft, and may be meshing type or non-meshing type. Further, the shape of the shaft may be a parallel type or a conical type, and in addition, a tandem system in which screw extruders are combined in multiple stages may be used.

<Method for producing polyacetal resin composition>
In the present embodiment, the type of the polyacetal resin composition is not particularly limited, and the resin composition is formed at the inlet of the extruder 10 that is replaced with the breaker plate 1 of the present embodiment from the conventionally known breaker plate 50. It will not be specifically limited if a raw material is supplied and a resin composition is obtained from the exit of the extruder 10. FIG.

  A thermoplastic resin composition is mentioned as a resin composition supplied to the extruder 10. The thermoplastic resin contained in the thermoplastic resin composition is not limited as long as it is a resin that is plasticized by application of shearing heat or heat, in addition to polyacetal (also referred to as polyoxymethylene, abbreviated as POM), Olefin resin, polyvinyl chloride, polyvinylidene chloride, acrylonitrile styrene copolymer, polystyrene, acrylic resin, methacrylic resin, polyamide, polycarbonate, polyvinyl alcohol, thermoplastic polyester, thermoplastic elastomer, polyphenylene sulfide, liquid crystal polymer, etc. Can be mentioned. These resins may be used alone or in combination of two or more.

  Among these, the extruder incorporating the breaker plate 1 of the present embodiment is particularly preferably used for granulation of a thermoplastic resin composition containing a thermoplastic polyurethane that easily adheres to a metal material as compared with a resin. Can do. For example, a thermoplastic resin composition comprising a polyacetal resin, 1 to 60 parts by weight thermoplastic polyurethane with respect to the polyacetal resin, and 1 to 10 parts by weight polyisocyanate compound with respect to the polyacetal resin. It can be used suitably for the granulation of a thing.

<Operation of this embodiment>
Hereinafter, the operation of the present embodiment will be described with reference to FIG. The breaker plate 1 has a plurality of holes 2 penetrating from one surface 1A toward the other surface 1B, and a boundary portion 3 separating adjacent holes 2 is directed from one surface 1A toward the other surface 1B. Tapered. In the flow path 30 on the outlet side of the tip 40 of the screw 40 in the extruder 10, the breaker plate 1 is disposed so that one surface 1A is on the inlet side and the other surface 1B is on the outlet side. And a raw material is supplied to the inlet 20 of the extruder 10, and the extruder 10 is operated. When the resin composition passing through the flow path 20 of the extruder 10 passes through the holes 2 of the breaker plate 1, the resin composition tapers according to the shape of the boundary portion 3 separating the adjacent holes 2 from the inlet side toward the outlet side. Form a stream. Therefore, it is possible to prevent the resin composition from staying on the back surface of the boundary portion 3.

  Further, an arbitrary one direction parallel to one surface 1A (surface on the extruder inlet side) and the other surface 1B (surface on the extruder outlet side) of the breaker plate 1 is defined as a first direction (X direction), and the inlet side The other direction different from the first direction is the second direction (Y direction), and the direction from the inlet side surface to the outlet side surface is the height direction (Z Direction), the height of the first boundary portion 3A having the first direction as the longitudinal direction is different from the height of the boundary portion having the second direction as the longitudinal direction. Therefore, when the resin composition passes through the hole 2 of the breaker plate 1, the flow of the resin composition can be disturbed on the back surface of the breaker plate 1, and as a result, the resin composition is agitated. Therefore, it is possible to further prevent the resin composition from staying on the back surface of the boundary portion 1.

<Effect of this embodiment>
Therefore, according to this embodiment, the breaker plate 1 for extruders which can suppress the residence of a resin composition still more less can be provided.

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

<Examples and Comparative Examples>
[Example 1]
The breaker plate 1 described in this embodiment (with a 100 mesh screen installed on the upstream side) was attached to the same direction meshing type twin screw extruder (TEX30 manufactured by Nippon Steel Works). Using this extruder, a polyacetal resin (polyacetal copolymer obtained by copolymerizing 96.7% by mass of trioxane and 3.3% by mass of 1,3-dioxolane, melt index (measured at 190 ° C., load 2160 g) ): 9 g / 10 min) 86.6% by weight, thermoplastic polyurethane (product name: Milactolan P480NAT, manufactured by Tosoh Corporation) 10% by weight, polyvalent isocyanate compound (product name: Bestanat T1890, manufactured by Degussa Japan) 1.0 weight %, And a polyacetal resin composition containing a hindered phenol-based antioxidant (Irganox 1010, manufactured by BASF). The polyacetal resin composition discharged from the extruder was pelletized using a strand cutter. The throughput of the extruder was set to 10 kg / hr, the screw rotation speed was set to 130 rpm, and the temperature in the flow path was set to 200 ° C.

[Comparative Example 1]
The same conditions as in Example 1 except that the breaker plate 1 has a conventionally known specification (the shape of the boundary portion is not tapered and the height of the first boundary portion and the second boundary portion is the same). A polyacetal resin composition was produced.

[Comparative Example 2]
Instead of the breaker plate 1, the boundary portion has a tapered shape, but under the same conditions as in Example 1 except that a breaker plate having the same height of the first boundary portion and the second boundary portion is used. A polyacetal resin composition was produced.

<Evaluation>
The hue of the polyacetal resin composition was visually confirmed every 10 minutes from the start of operation of the twin screw extruder. The time from the start of operation of the twin screw extruder to the first time the presence of carbide was recognized was taken as the continuous operation time of the twin screw extruder.

  As a result, the continuous operation time of Example 1 was 130 hours. On the other hand, the continuous operation time of Comparative Example 1 was 50 hours, and the continuous operation time of Comparative Example 2 was 100 hours.

  From this result, if the breaker plate 1 having the shape described in the present embodiment is used, it is possible to further reduce the retention of the resin composition. As a result, the frequency with which the inside of the extruder is disassembled and cleaned can be minimized, and the economy is excellent.

DESCRIPTION OF SYMBOLS 1 Breaker plate for extruder 1A One side 1B The other side 2 Hole 3 Boundary part 3A 1st boundary part 3B 2nd boundary part

Claims (5)

Having a plurality of holes penetrating from one surface to the other surface;
The boundary part separating adjacent holes is tapered from the one surface to the other surface,
Any one direction parallel to the one surface and the other surface is defined as a first direction, and the other one direction that is parallel to the one surface and the other surface and is different from the first direction is defined as a second direction. And when the direction from the one surface to the other surface is the height direction, the height of the boundary portion having the first direction as the longitudinal direction and the boundary having the second direction as the longitudinal direction Breaker plate for extruder with different height.   The part breaker plate for an extruder according to claim 1, wherein the hole has a substantially square shape. The substantially square shape is a substantially rectangular shape or a substantially square shape,
The breaker plate for an extruder according to claim 2, wherein the first direction and the second direction are substantially perpendicular. Screw,
A breaker plate for an extruder according to any one of claims 1 to 3,
The extruder breaker plate is an extruder in which the one surface is on the inlet side and the other surface is on the outlet side in the flow path on the outlet side of the tip of the screw.   The inlet of the extruder according to claim 4, polyacetal resin, 1 to 60 parts by weight of thermoplastic polyurethane with respect to the polyacetal resin, and 1 to 10 parts by weight with respect to the polyacetal resin. A method for producing a polyacetal resin composition, wherein the polyacetal resin composition is obtained by supplying a polyacetal resin composition from the outlet of the screw extruder.

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