Extrusion molding machine filters

Abstract

To provide a filter for an extruder, which can prevent holding of a molding material that is flowed into a housing and eliminate a risk of deterioration of a quality of a resin film due to the generation of foreign matters.SOLUTION: A filter 20 for an extruder is provided with a melt extruder that extrudes a molding material and a T-die that molds the molding material from the melt extruder into a resin film, and filters the molding material extruded from the melt extruder to the T-die. The filter is provided with a housing that is interposed between the melt extruder that melts and extrudes at least a resin-containing molding material and the T-die, and an element body 28 that is housed in the housing and filters the molding material. A through hole 40 is drilled in a downstream other end 32 of the element body 28 to allow the molding material in a downstream part of the housing to flow therein to prevent holding of the material.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a filter for an extrusion molding machine that filters a molding material flowing from an extrusion molding machine to a die to remove foreign matters.

Background Art

[0002] Conventionally, when molding a molding material 1 into a resin film 2, as shown in FIGS. 5 and 6, a melt extrusion molding machine 10 that melts and extrudes the molding material 1, and a T-die 13 that molds the molding material 1 from the melt extrusion molding machine 10 into a thin resin film 2 are used. A filter 20 that filters the molding material 1 to remove foreign matters is attached between the melt extrusion molding machine 10 and the T-die 13 (see Patent Document 1).

[0003] The molding material 1 is prepared by containing at least a resin such as a polyether ether ketone resin. A connecting pipe 12 for flowing the molding material 1 is inserted into the tip of the melt extrusion molding machine 10. The T-die 13 is supported by the connecting pipe 12, and a filter 20 interposed between the melt extrusion molding machine 10 and the T-die 13 is attached.

[0004] As shown in FIGS. 5 and 6, the filter 20 includes a housing 21 interposed between the melt extrusion molding machine 10 and the T-die 13, and an element body 28 housed in the housing 21 for filtering the molding material 1. The housing 21 includes a main body 22 that houses the central portion of the element body 28 via a gap C, a first lid body 23 attached to the main body 22 and communicating with the melt extrusion molding machine 10, and a second lid body 24 attached to the main body 22 and communicating with the T-die 13. One end portion 31 of the element body 28 is housed in the first lid body 23 via the gap C. A screw hole 26 for the element body 28 is drilled in the central portion of the second lid body 24, and a taper 27 that is inclined toward the T-die 13 and connects to the screw hole 26 is formed on the inner surface of the second lid body 24.

[0005] As shown in Figure 6, the element body 28 is constructed by housing a filtration element 30 in a housing 29. The downstream end 32 is tapered to facilitate installation and approaches the taper 27 of the second lid 24 of the housing 21 via a gap C, while the furthest downstream end 33 is screwed into the screw hole 26 of the second lid 24.

[0006] In the above process, when molding the molding material 1 into a resin film 2, the molding material 1 is extruded in a molten state from the melt extrusion molding machine 10, flows through the connecting pipe 12, and enters the housing 21 and element body 28 of the filter 20, respectively (see arrows in Figure 6). The molding material 1 that has entered the housing 21 flows sequentially through the first lid 23, the main body 22, and the second lid 24, and accumulates in the area where the second lid 24 and the other end 32 of the element body 28 are close together, specifically near the boundary between the screw hole 26 and the taper 27 of the second lid 24, and in the stagnant area S partitioned by the other end 32 of the element body 28.

[0007] In contrast, the molding material 1 that flows into the element body 28 flows sequentially through one end 31 and element 30 of the element body 28, separating any unmelted resin or gel foreign matter. After that, it flows sequentially through the other end 33 and the connecting pipe 12, flowing towards the T-die 13, and is continuously molded into a thin resin film 2. [Prior art documents] [Patent Documents]

[0008] [Patent Document 1] Japanese Patent Publication No. 2022-83576 [Overview of the Initiative] [Problems that the invention aims to solve]

[0009] In conventional extrusion molding machines, the filter 20 is configured as described above, and the stagnant area S partitioned by the second lid 24 and the other end 32 of the element body 28 becomes a dead zone where the molding material 1 does not flow. As a result, the molding material 1 that flows into the housing 21 remains in the stagnant area S, and if more than 24 hours have passed since the start of the molding operation, burning occurs continuously in the stagnant area S, and the stagnant molding material 1 becomes degraded material. Consequently, a large amount of foreign matter (for example, cross-linked gel, etc.) is generated by the degraded material and gradually passes through the filter 20, potentially adversely affecting the resin film 2 and degrading its quality.

[0010] The problem is that when the molding material 1 consists solely of resin, and this resin is a high-performance thermoplastic resin, such as a polyaryletherketone resin, oligomers and low-molecular-weight components are generated during polymerization, which can become gel foreign matter. As a result, there is a significant risk that foreign matter will be mixed into the thin resin film 2, degrading its quality.

[0011] The present invention has been made in view of the above, and aims to provide a filter for an extrusion molding machine that can suppress the accumulation of molding material that flows into the housing and eliminate the risk of foreign matter generation and deterioration of the quality of the resin film. [Means for solving the problem]

[0012] In order to solve the above problems, the present invention comprises an extrusion molding machine for extruding a molding material, a die for forming the molding material from the extrusion molding machine into a resin film, and a filter for the molding material extruded from the extrusion molding machine into the die. The invention comprises a housing interposed between an extrusion molding machine and a die for melting and extruding a molding material containing at least a resin, and an element body housed in the housing for filtering the molding material, wherein the element body is provided with flow holes that allow the molding material in the housing to flow in and restrict its retention.

[0013] The resin used for molding can be at least one of nylon resin, polyetherimide resin, and polyaryletherketone resin.

[0014] Furthermore, the housing includes a main body that houses the approximate center of the element body with a gap in between, a first lid attached to the main body and communicating with (connecting through) the extrusion molding machine, and a second lid attached to the main body and communicating with the die. One end of the element body is housed in the first lid with a gap in between, and a mounting hole for the element body is provided in the second lid. The inner surface of the second lid has a taper that gradually slopes toward the die direction and connects to the mounting hole. The element body is configured such that the element is housed in a housing, with one end being tapered and the other end being tapered so that it approaches the taper of the second lid of the housing with a gap between them, and the other end being attached to the mounting hole of the second lid.

[0015] Furthermore, either a recess or a protrusion can be formed on the opposing surfaces of the main body, the first lid, and the second lid of the housing, so that the main body, the first lid, and the second lid can be fitted together with a recessed and protruding structure. Furthermore, the main body of the housing can be formed hollow, and its inner surface can be gradually inclined inward as it moves from the direction of the extrusion molding machine towards the direction of the die. Furthermore, the flow-through holes are provided at the other end of the element body, and it is preferable that the hole width is 0.4 mm or more.

[0016] Here, the molding material in the claims may include various fillers in addition to resin. The resin of this molding material is preferably an engineering plastic with heat resistance of 100°C or higher, or a super engineering plastic with heat resistance of 150°C or higher. The resin film may be transparent, opaque, or translucent, and is not limited to any particular application such as medical, industrial, industrial materials, agricultural, packaging, circuit boards, optical, shielding, or diaphragm for small speakers. There may be one or more flow holes. These flow holes can be circular, elliptical, rectangular, polygonal, or grooved.

[0017] According to the present invention, when forming a molding material into a resin film, the molding material is extruded from an extrusion molding machine and flows into the housing of the filter and the element body. The molding material flowing into the housing sequentially flows through the upstream part, the downstream part of the housing, and the flow holes of the element body, and flows into the inside of the element body. Since the molding material flows from the housing into the element body, the molding material is less likely to stay in the downstream part of the housing.

Effect of the Invention

[0018] According to the present invention, there is an effect that it is possible to suppress the retention of the molding material flowing into the housing, and to wipe out the possibility that foreign matter is generated and the quality of the resin film is deteriorated.

[0019] According to the invention described in claim 2, when the resin of the molding material is at least any one of a nylon resin, a polyetherimide resin, and a polyaryl ether ketone resin, it is possible to prevent burning and the generation of foreign matter recognized according to empirical rules.

[0020] According to the invention described in claim 3, since the housing of the filter is constituted by being divided into a main body, a first lid body, and a second lid body, the manufacture and maintenance of the housing are facilitated. Further, since one end portion of the element body is subjected to a necking process, the flow rate of the molding material extruded from the extrusion molding machine can be improved. Further, since the other end portion downstream of the element body is subjected to a necking process, it is possible to easily and surely fix the other end portion to the mounting hole of the second lid body.

[0021] According to the invention described in claim 4, since a flow hole is provided at the other end portion of the element body and the hole width of this flow hole is 0.4 mm or more, it is possible to increase the flow rate of the molding material and suppress the retention of the molding material, and it is possible to reduce the number of foreign matters in the resin film.

Brief Description of the Drawings

[0022] [Figure 1] It is an overall explanatory view schematically showing an embodiment of a filter of an extrusion molding machine according to the present invention. [Figure 2]It is a cross-sectional explanatory view schematically showing a housing in an embodiment of a filter of an extrusion molding machine according to the present invention. [Figure 3] It is an explanatory view schematically showing an element body in an embodiment of a filter of an extrusion molding machine according to the present invention. [Figure 4] It is a main part explanatory view schematically showing a flow hole in an embodiment of a filter of an extrusion molding machine according to the present invention. [Figure 5] It is an explanatory view schematically showing a conventional filter of an extrusion molding machine. [Figure 6] It is a cross-sectional explanatory view schematically showing a filter of an extrusion molding machine.

Mode for Carrying Out the Invention

[0023] Hereinafter, referring to the drawings, a preferred embodiment of the present invention will be described. The filter 20 of the extrusion molding machine in this embodiment is, as shown in FIGS. 1 to FIGS. 4 and FIG. 6, at least a melting and extruding melt extrusion molding machine 10 for melting and extruding a molding material 1 containing resin and a housing 21 interposed between the T-die 13, and an element body 28 housed in the housing 21 for filtering the molding material 1. A necessary number of flow holes 40 for allowing the molding material 1 in the housing 21 to flow in and restricting the retention are provided in the element body 28, thereby contributing to the achievement of Goal 9 of the SDGs (Sustainable Development Goals adopted at the United Nations Summit, sustainable development goals consisting of 17 global goals and 169 targets (achievement criteria)).

[0024] The molding material 1 is prepared using at least one of the following as the main component: a predetermined thermoplastic resin, such as nylon (polyamide) resin, polyetherimide resin, or polyaryletherketone resin, which are empirically known to cause burning and the generation of foreign matter. Among these resins, polyaryletherketone (PAEK) resin, specifically polyetherketone (PEK) resin, polyetheretherketone (PEEK) resin, and polyetherketoneketone (PEKK) resin are suitable, and polyetheretherketone resin is the most suitable, as they are super engineering plastics with high molding temperatures (300°C to 450°C) and no preferred antioxidants.

[0025] Polyaryl ether ketone resins may be used individually, as a mixture of two or more types, or as copolymers. These polyaryl ether ketone resins are generally used in powder, granular, or pellet forms suitable for molding. There are no particular limitations on the manufacturing method of polyaryl ether ketone resins, but examples include the method described in the literature [Asahi Research Center Co., Ltd.: Super Engineering Plastics Growing in Advanced Applications - PEEK (Part 1)].

[0026] Polyether ether ketone resin is a crystalline thermoplastic resin composed of arylene groups, ether groups, and carbonyl groups, and exhibits excellent mechanical properties, lightness, electrical insulation properties, hydrolysis resistance, heat resistance, and chemical resistance. This polyether ether ketone resin has a melting point of typically 320°C to 360°C, preferably 335°C to 345°C, and is usually used in powder, granular, or pellet form, which is suitable for molding. Examples of such polyether ether ketone resin products include the Victrex Powder series and Victrex Granules series from Victrex Corporation, the Vestakeep series from Polypla Evonik Corporation, and the Keetasspire PEEK series from Solvay Specialty Polymers Corporation.

[0027] The molding material 1 may consist of resin alone, but various additives may be selectively added as long as they do not impair the objectives of the present invention. For example, nucleating agents, antioxidants, heat stabilizers, lubricants, antistatic agents, antiblocking agents, fillers, viscosity modifiers, color inhibitors, etc., may be added as needed.

[0028] As shown in Figure 1, the melt extrusion molding machine 10 consists of, for example, a single-screw extruder or a twin-screw extruder that melts and kneads the molding material 1 with a screw, and a raw material inlet 11 for the molding material 1, consisting of a hopper, is installed at the rear upper part. An inert gas supply pipe for supplying an inert gas such as helium gas, argon gas, or nitrogen gas is connected to this raw material inlet 11 as needed, and the supply of inert gas by this inert gas supply pipe effectively prevents oxidative degradation, oxygen crosslinking, and thermal crosslinking of the molding material 1. In addition, a connecting pipe 12 for flowing the molding material 1 is horizontally connected to the front of the melt extrusion molding machine 10, and a T-die 13 for forming a thin resin film 2 is attached to the downstream part of this connecting pipe 12, and a replaceable filter 20 interposed between the melt extrusion molding machine 10 and the T-die 13 is attached near the middle part of the connecting pipe 12.

[0029] As shown in Figure 1, the T-die 13 is configured to extrude the molding material 1 that has flowed through the manifold with high precision from the lip, which is the discharge port, and functions to continuously extrude a strip-shaped resin film 2 downwards. Below the T-die 13, a pair of rolls 14 are rotatably supported, spaced apart and facing each other, sandwiching the high-temperature resin film 2. One of these rolls 14 serves as a cooling roll for the resin film 2, and the other roll 14 serves as a pressing roll that presses the resin film 2 against the cooling roll. A metal roll or the like is used as the cooling roll, and a metal elastic roll or the like, in which a rubber layer such as silicone rubber or fluororubber is covered on the circumferential surface of a metal roll, is used as the pressing roll.

[0030] The pair of rolls 14 adjust the thickness of the resin film 2, which is preferably 3 μm to 1000 μm, more preferably 10 μm to 500 μm, and more preferably 50 μm to 300 μm. This is because if the thickness is less than 3 μm, the tensile strength of the resin film 2 decreases significantly, making it prone to breakage during manufacturing and reducing manufacturing efficiency. On the other hand, if the thickness exceeds 1000 μm, the tensile tension becomes excessive.

[0031] Downstream of the pair of rolls 14, a winding machine 15 is installed to wind the resin film 2 onto a rotatable winding tube. Between the winding machine 15 and the pair of rolls 14, tension rolls 16 are rotatably supported in the necessary number of positions to apply tension to the resin film 2 for smooth winding. In addition, a vertically movable slitting blade is selectively positioned between the pair of rolls 14 and the winding machine 15 to form slits in the longitudinal direction along the sides of the resin film 2.

[0032] As shown in Figures 2 and 6, the housing 21 of the filter 20 comprises, from the viewpoint of facilitating manufacturing and disassembly, a hollow body 22 that accommodates the approximately central part of the element body 28, excluding both ends, with a small gap C; a first lid 23 that is attached to the opening of the body 22 and communicates with the upstream melt extrusion molding machine 10 via a connecting pipe 12; and a second lid 24 that is attached to the opening of the body 22 and communicates with the downstream T-die 13 via a connecting pipe 12. The body 22 located in the middle, the first lid 23 located on the upstream side, and the second lid 24 located on the downstream side are each made of stainless steel or the like.

[0033] The main body 22 has a hollow section with the same diameter upstream and downstream. However, if it is desired to improve the flow velocity of the molding material 1, the inner surface of the hollow section is formed to gradually slope inward from upstream to downstream. The first and second lids 23 and 24 are each formed with a recessed, roughly mortar-shaped cross section, and a communication port 25 is drilled in the center of each to connect to the connecting pipe 12. The first lid 23 has a roughly funnel-shaped cavity, in which one end 31 of the element body 28 is housed with a small gap C. The second lid 24 has a screw hole 26 drilled in the center for the element body 28 that communicates with the communication port 25, and a skirt-shaped taper 27 is formed on the inner surface of the second lid 24, which gradually slopes inward toward the T-die 13 and connects to the periphery of the screw hole 26.

[0034] As shown in Figures 3, 4, and 6, the element body 28 of the filter 20 is configured in a roughly cylindrical shape with a filtration element 30 housed in a roughly hollow cylindrical housing 29. The upstream end 31, which has good flow, is drawn into a roughly conical shape with a reduced diameter to increase the flow velocity of the molding material 1, and this end 31 is housed in the first lid 23 of the housing 21 with a small gap C. The element 30 is not particularly limited, but for example, a screen with many meshes or metal fibers can be used. The other downstream end 32 of the element body 28 is drawn into a reduced diameter and approaches the taper 27 of the second lid 24 of the housing 21 with a small gap C, and is integrated with the other end 33, which is a roughly cylindrical shape with a reduced diameter and communicates with the element 30. This other end 33 is located at the downstream end and is screwed into the screw hole 26 of the second lid 24.

[0035] As shown in Figure 4, the flow holes 40 consist of small-diameter, round through holes drilled radially in the other end 32 of the housing 29 of the element body 28. They function to allow the molding material 1 to flow into the housing 29 through the small gap C between the taper 27 of the second lid 24 of the housing 21 and the other end 32 of the element body 28, thereby restricting stagnation in the stagnation area S. The number of these flow holes 40 is not particularly limited, but is one or more, preferably one, two, three, or four.

[0036] When there are multiple flow holes 40, the flow holes 40 are drilled at intervals of 180°, 120°, 90°, etc., from the viewpoint of evenly distributing the inflow points. Furthermore, the diameter of the flow holes 40 is preferably 0.4 mm or more, more preferably 0.4 mm or more and 1.5 mm or less, more preferably 0.45 mm or more and 1.2 mm or less, and even more preferably 0.5 mm or more and 1.0 mm or less, from the viewpoint of increasing the flow velocity of the incoming molding material 1. This is because if the diameter of the flow holes 40 is less than 0.4 mm, the flow velocity of the molding material 1 will decrease, and there is a risk of stagnation.

[0037] In the above configuration, when the molding material 1 is molded into a resin film 2 by melt extrusion molding, the molding material 1 is extruded in a molten state from the melt extrusion molding machine 10, flows through the connecting pipe 12, and flows into the housing 21 and element body 28 of the filter 20, respectively. The molding material 1 that has flowed into the housing 21 flows sequentially through the small gap C in the first lid 23, the small gap C in the main body 22, the small gap C in the second lid 24, and the flow hole 40 of the element body 28, and flows into the other end of the element in the element body 28. Since the molding material 1 flows into the bypass flow hole 40, the molding material 1 does not accumulate near the boundary between the screw hole 26 and the taper 27 of the second lid 24, and in the stagnant area S partitioned by the other end 32 of the element body 28.

[0038] The molding material 1 that flows into the element body 28 flows sequentially through one end 31 and the central element 30 of the element body 28, separating any unmelted resin or gel foreign matter. After that, it flows sequentially through the other end 33 and the connecting pipe 12, flowing towards the T-die 13, and is continuously molded into a thermoplastic thin film resin film 2. When the molding material 1 is polyetheretherketone resin, the resin film 2 is melt-extruded to a crystallinity of 1% to 15%, preferably 2% to 12%, and more preferably 5% to 10%. This is because if the crystallinity is less than 1%, it becomes difficult to manufacture the resin film 2, and if it exceeds 15%, the stretch tension becomes excessive, making the resin film 2 prone to tearing, uneven stretching, pinholes, etc.

[0039] With the above configuration, the molding material 1 downstream of the housing 21 flows into the flow holes 40 of the element body 28, eliminating dead zones where the molding material 1 does not flow. Even if 8 hours or more have passed since the start of the molding process, burning due to stagnation does not occur continuously, and the stagnant molding material 1 does not deteriorate. Therefore, the risk of a large amount of foreign matter being generated, gradually passing through the filter 20, and adversely affecting the resin film 2 and degrading its quality can be effectively eliminated.

[0040] The effect is extremely significant because, when the molding material 1 consists solely of resin, and this resin is a high-temperature super engineering plastic, specifically polyaryletherketone resin, polyether resin, polyetheretherketone resin, or polyetherketoneketone resin, there is less risk of foreign matter being mixed into the resin film 2 and degrading its quality.

[0041] In the above embodiment, a T-die 13 was attached to the connecting pipe 12, but a round die or the like may also be attached. Also, in the above embodiment, a filter 20 was attached to the connecting pipe 12, but by attaching a gear pump to the connecting pipe 12, the molding material 1 that has been melted and kneaded by the melt extrusion molding machine 10 may be transferred to the downstream filter 20 at a constant flow rate and with high precision. Furthermore, in the above embodiment, one roll 14 of the pair of rolls 14 was used as a cooling roll and the other roll 14 was used as a compression roll, but this is not the only way to go. For example, the pair of rolls 14 may be used as compression rolls, and the number of cooling rolls necessary to cool the resin film 2 may be rotatably supported between this pair of compression rolls and the winding machine 15.

[0042] Furthermore, the pair of rolls 14 may have the same diameter or different diameters. Also, recesses or protrusions can be formed on the opposing surfaces of the main body 22, the first lid 23, and the second lid 24 of the housing 21, and these can be fitted together to prevent the first lid 23 or the second lid 24 from falling off. In addition, the main body 22 of the housing 21 and the first lid 23 or the second lid 24 can be integrated to divide the housing 21 into two parts, or the housing 21 can be divided into two parts in the vertical direction of Figure 1. Furthermore, the element body 28 can be configured in the shape of a polygonal column, for example. [Examples]

[0043] The following describes examples of the filter for an extrusion molding machine according to the present invention, along with comparative examples. [Example 1] To manufacture the resin film, a commercially available polyetheretherketone resin was first prepared. This polyetheretherketone resin was then placed in a dehumidifying dryer heated to 160°C and dried for more than 12 hours to obtain the molding material. The polyetheretherketone resin used was Keetasspire PEEK KT-851NL SP [manufactured by Solvays Pestilute Polymers: product name].

[0044] Next, a melt extrusion molding machine consisting of a single-screw extruder with a T-die, as shown in Figure 1, was prepared. A connecting pipe for flowing the molding material was horizontally connected to the tip of the single-screw extruder, a T-die was mounted downstream of this connecting pipe, and a filter interposed between the single-screw extruder and the T-die was mounted in the middle of the connecting pipe. The filter had the configuration shown in Figures 2 to 4 and 6, consisting of a housing interposed between the single-screw extruder and the T-die, and a substantially cylindrical element body housed in this housing for filtering the molding material. A single flow hole with a diameter of 1 mm was drilled in the radial direction at the other end of the housing that constitutes the element body to restrict the accumulation of the molding material.

[0045] After preparing a melt extrusion molding machine equipped with a T-die, the molding material was set in the melt extrusion molding machine and melted and kneaded. This melted and kneaded molding material was continuously extruded from the T-die and cooled by being sandwiched between a pair of rolls adjusted to a temperature of 150°C, thereby extruding a 100 μm thick resin film into a strip shape. At this time, the temperature of the melt extrusion molding machine was adjusted to 380°C to 400°C, the temperature of the T-die was adjusted to 400°C, and the temperature of the connecting pipe linking the melt extrusion molding machine and the T-die was also adjusted to 400°C. The temperature of the molten molding material was measured by taking the resin temperature at the T-die inlet, which was found to be 397°C.

[0046] Next, the continuous resin film was sequentially wound onto the winding tube of a winding machine. After 24 hours, the number of foreign objects in a 1000m length of resin film was measured, and the quality evaluation results were summarized in Table 1 using the format ◎○×. For measuring foreign objects, a CCD camera and light source were used, and the area projected onto the resin film was 0.8mm². 2 The shadows (dark defects) described above were defined as foreign matter. In addition, the quality evaluation results indicate the following: ◎ indicates a significant improvement in the quality of the resin film, ○ indicates an improvement in the quality of the resin film, and × indicates a decrease in the quality of the resin film.

[0047] [Example 2] The procedure was basically the same as in Example 1, but four 1 mm diameter flow holes were drilled in the radial direction of the other end of the housing constituting the element body. The four flow holes were drilled at 90° intervals in the circumferential direction of the other end of the housing. The continuous resin film was wound sequentially onto the winding tube of a winding machine, and after 24 hours, the number of foreign objects in the 1000 m length of resin film was measured, and the quality evaluation results were summarized in Table 1 in the format ◎○×.

[0048] [Example 3] The procedure was basically the same as in Example 1, but one 0.5 mm diameter flow hole was drilled in the other end diameter direction of the housing constituting the element body. The continuous resin film was sequentially wound onto the winding tube of a winding machine, and after 24 hours, the number of foreign objects in the 1000 m length of resin film was measured, and the quality evaluation results were summarized in Table 1 in the format ◎○×.

[0049] [Example 4] The procedure was basically the same as in Example 1, but four 0.5 mm diameter flow holes were drilled in the radial direction of the other end of the housing constituting the element body. The four flow holes were drilled at 90° intervals in the circumferential direction of the other end of the housing. The continuous resin film was wound sequentially onto a winding machine, and after 24 hours, the number of foreign objects in the 1000 m length of resin film was measured, and the quality evaluation results were recorded in Table 1 using the format ◎○×.

[0050] [Comparative Example] To manufacture the resin film, a commercially available polyetheretherketone resin was prepared and dried in a dehumidifying dryer heated to 160°C for more than 12 hours to obtain the molding material. The polyetheretherketone resin was the same as in Example 1.

[0051] Next, a melt extrusion molding machine consisting of a single-screw extruder with a T-die, as shown in Figure 1, was prepared. A connecting pipe for flowing the molding material was inserted into the tip of the single-screw extruder, and the T-die was supported at the downstream end of this connecting pipe. A filter interposed between the single-screw extruder and the T-die was attached to the connecting pipe. The filter had the configuration shown in Figure 6, which included a housing interposed between the single-screw extruder and the T-die, and an element body housed in this housing for filtering the molding material. Unlike the embodiment, no flow holes were drilled at the other end of the element body.

[0052] A melt extrusion molding machine equipped with a T-die was prepared. The molding material was set in the melt extrusion molding machine and melted and kneaded. This melted and kneaded molding material was continuously extruded from the T-die and cooled by being sandwiched between a pair of rolls adjusted to a temperature of 150°C, thereby extruding a 100 μm thick resin film into a strip shape. At this time, the temperature of the melt extrusion molding machine was adjusted to 380°C to 400°C, the temperature of the T-die was adjusted to 400°C, and the temperature of the connecting pipe linking the melt extrusion molding machine and the T-die was also adjusted to 400°C. The temperature of the molten molding material was measured by measuring the resin temperature at the T-die inlet, which was found to be 397°C.

[0053] Next, the continuous resin film was wound sequentially onto the winding tube of the winding machine. After 24 hours, the number of foreign objects in the 1000m length of resin film was measured, and the quality evaluation results were recorded in Table 1 using the format ◎○×. The measurement of foreign objects and the quality evaluation results were the same as in Example 1.

[0054] [Table 1]

[0055] 〔evaluation〕 In each of the embodiments, flow holes were perforated in the filter element to prevent the accumulation of the molding material, resulting in a reduction of the number of foreign particles in the resin film to eight or fewer, thus improving the quality of the resin film. In particular, in embodiments 3 and 4, the number of foreign particles in the resin film was reduced to three or fewer, demonstrating a significant improvement in the quality of the resin film. In contrast, in the comparative example, a conventional filter was used, and the flow holes in the element body were omitted, resulting in 10 foreign particles in the resin film. This led to a decrease in the quality of the resin film and raised doubts about its practicality. [Industrial applicability]

[0056] The filter for an extrusion molding machine according to the present invention is used in the field of resin film manufacturing. [Explanation of symbols]

[0057] 1 Molding material 2. Resin film 10. Melt extrusion molding machine (extrusion molding machine) 12 Connecting pipe 13 T-Dice (Dice) 20 filters 21. Enclosure 22 Main unit 23 The first lid 24 The second lid 26 Screw holes (mounting holes) 27 Taper 28 Element Body 29 Housing 30 elements 31 One end 32 Other end 33 The other end 40 Flow hole C Gap S retention part

Claims

1. An extrusion molding machine comprising an extrusion molding machine for extruding a molding material and a die for forming the molding material from the extrusion molding machine into a resin film, wherein the filter for filtering the molding material extruded from the extrusion molding machine into the die, A filter for an extrusion molding machine, comprising a housing interposed between an extrusion molding machine and a die for melting and extruding a molding material containing at least a resin, and an element body housed in the housing for filtering the molding material, wherein the element body is provided with flow holes for allowing the molding material in the housing to flow in and restricting its retention.

2. The filter for an extrusion molding machine according to claim 1, wherein the resin of the molding material is at least one of nylon resin, polyetherimide resin, and polyaryletherketone resin.

3. The housing includes a main body that houses the approximate center of the element body with a gap between it and the main body, a first lid attached to the main body and communicating with the extrusion molding machine, and a second lid attached to the main body and communicating with the die. One end of the element body is housed in the first lid with a gap between it and the second lid, and a mounting hole for the element body is provided in the second lid. The inner surface of the second lid has a taper that gradually slopes toward the die and connects to the mounting hole. The filter for an extrusion molding machine according to claim 1 or 2, wherein the element body is configured such that the element is housed in a housing, one end of which is drawn and the other end of which is drawn so as to approach the taper of the second lid of the housing with a gap between them, and the other end of which is attached to the mounting hole of the second lid.

4. The filter for an extrusion molding machine according to claim 3, wherein the flow holes are provided at the other end of the element body and the hole width is 0.4 mm or more.

Images