JP2012192647A - Adapter with back pressure adjusting apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate a flow speed difference of a melted resin, to smooth the flow of the melted resin, to decrease a retention resin in an adapter with a back pressure adjusting apparatus, and to decrease a deteriorated resin caused by the retention resin by suppressing the decrease in the flow speed of the melted resin flowing near a valve rod of a needle valve in the adapter with the back pressure adjusting apparatus provided in the midway of a resin flow path in which the melted resin kneaded and extruded from a screw of an extruder flows.SOLUTION: In the adapter with the back pressure adjusting apparatus, the cross-section orthogonal to the axial direction of the valve rod of the needle valve of the back pressure adjusting apparatus, is made to be an ellipse, to smooth the flow in the adapter, to decrease the retention resin of the melted resin and to decrease the deteriorated resin caused by it.

Description

  The present invention relates to a flow path in an adapter connected to an extruder, and smoothes the resin flow in the adapter by remodeling a cross-sectional shape perpendicular to the valve stem axis direction of a needle valve of a back pressure adjusting device attached to the adapter. Thus, the present invention relates to reducing the retained resin that is the cause of the deteriorated resin.

  An extruder for coating a resin layer on the surface of a thin film substrate such as a resin film or a linear substrate such as a metal wire, or laminating a resin layer between a plurality of substrates, The melted resin, which is kneaded by a screw, is extruded from the outlet of a die having a predetermined cross-sectional shape.

  The extrusion amount of the molten resin is determined by the cylinder and screw volumes, screw shape, and screw rotation speed. When the amount of extrusion increases, the back pressure increases, excessive kneading occurs with the screw, and the dissolved resin generates heat and deteriorates. On the other hand, if the amount is small, the back pressure becomes small and kneading with the screw becomes insufficient. Thus, the back pressure applied to the screw of the extruder affects the quality of the extruded resin. Therefore, a back pressure adjusting device is installed.

  There is an example of using an orifice as a back pressure adjusting device (see, for example, Patent Document 1). A cross-sectional view of a back pressure adjusting device using an orifice is shown in FIG.

  In FIG. 2, reference numeral 2101 denotes a cylinder as a barrel of the extruder. A screw 2102 that is rotated by a drive source (not shown) is disposed in the cylinder 2101. Further, a filtration device 2103 is provided at the front end of the cylinder 2101, and an adapter 2107 having a back pressure adjusting device for bending the flow path of the molten resin pushed out by the screw 2102 at a right angle is attached to the downstream side thereof. Further, a lead-out pipe 2105 connected to a die (not shown) is attached to the adapter 2107. The filtration device 2103 at the tip of the cylinder 2101 is composed of a screen mesh and a breaker plate 2106 that supports the screen mesh, and serves to remove foreign matters mixed in the dissolved resin.

  Next, the flow path will be described. The molten resin extruded to the screw 2102 passes through the flow path 2201 and passes through the breaker plate 2106. After passing through the breaker plate 2106, it passes through the flow path 2202 in the adapter 2107 that is concentric with the screw 2102, the orifice 2203 b of the movable block 2118, the flow path 2204 of the fixed block 2119, the flow path 2205 b of the movable block 2118, and the screw It passes in the order of the flow path 2206 in the adapter 2107 that is orthogonal to the center 2102 and flows to the outlet pipe 2105 connected to a die (not shown).

  The back pressure adjusting device of the adapter 2107 will be described. The movable block 2118 has a handle (not shown), and rotates with respect to the fixed block 2119 by turning the handle. The movable block 2118 is provided with several orifices 2203a to 2203d (in FIG. 2, four types of orifices having different inner diameters are provided). The back pressure adjusting device is performed by adjusting the resistance applied to the dissolved resin by the orifice. Therefore, the back pressure is adjusted by selecting an orifice suitable for the back pressure.

  However, in this system, once the orifice is changed, the previously used orifice cannot be used again. The reason is that the dissolved resin remaining in the orifice becomes a deteriorated resin, and when this adheres to the product, it affects the appearance, mechanical properties and the like. Again, since the movable block 2118 must be exchanged for use, it takes time and effort.

  In addition, since the inner diameter of the orifice processed in the movable block 2118 is determined, it is not possible to perform the minute back pressure adjustment that is required when the operating conditions are changed slightly.

  There is also a method of adjusting the back pressure using a needle valve. FIG. 3 shows a cross-sectional view of an adapter with a back pressure adjusting device using a needle valve 3108.

  First, the part of the needle valve 3108 will be described with reference to FIG.

  The needle valve 3108 comprises a valve body 3117 that changes the volume of the flow path with a conical tip, a valve rod 3116 that is processed with a screw, and 3120 to which a drive device such as a handle is attached.

  Next, the flow path will be described with reference to FIG. The dissolved resin extruded to the screw 3102 passes through the flow path 3201 and the breaker plate 3106 in the flow path in the filtration device 3103. After passing through the breaker plate 3106, it passes through the flow path 3202 in the adapter 3107 concentric with the screw 3102, flows through the flow path 3203 along the valve body of the needle valve 3108, and enters the adapter 3107 concentrically with the screw 3102. It flows through the flow path 3206 and flows to the outlet pipe 3105 connected to a die (not shown).

  A closing member 3109 for closing the flow path is attached to the adapter 3107 on the opposite side of the flow path 3202 between the filtering device 3103 and the adapter 3107. An insertion hole is formed in the closing member 3109, and the needle valve 3108 is inserted into the insertion hole. A nut member 3110 is attached to the closing member 3109, and a male screw formed on a valve rod of the needle valve 3108 is screwed to the nut member 3110. The needle valve 3108 is provided with a handle, expansion / contraction drive means, etc. (not shown). Accordingly, when the operator operates the handle to rotate the needle valve 3108, the needle valve 3108 moves in the axial direction. Reference numeral 3111 denotes a seal member for preventing the molten resin from leaking from the gap between the insertion hole of the closing member 3109 and the outer periphery of the needle valve 3108, and is fixed by a seal pressing member 3112.

  In the back pressure adjusting device, the operator operates the handle to rotate the needle valve 3108 to adjust the back pressure applied to the screw 3102. In this case, when the needle valve 3108 is rotated and moved in the axial direction, the valve body of the needle valve 3108 changes the resin flow path 3203, and the resistance given to the dissolved resin passing through the flow path changes. The dynamic pressure of the dissolved resin changes, and the back pressure applied to the screw 3102 changes. Thereby, the back pressure applied to the screw 3102 can be adjusted to a desired value.

  The flow near the needle valve 3108 will be described in detail.

  As shown in FIG. 5, the resin passing through the resin flow path 3203 is a dissolved resin passing through the upper side of the needle valve 3108 (hereinafter referred to as a dissolved resin α for convenience) and the needle valve as shown in FIG. A distinction is made between dissolved resin passing below 3108 (hereinafter referred to as dissolved resin β for convenience). Since the melted resin α flows while contacting the valve rod 3116 of the needle valve 3108 in the circumferential direction, the flow rate of the melted resin is slow in the vicinity of the valve rod 3116 of the needle valve 3108. On the other hand, the dissolved resin β has a smaller range in contact with the valve rod 3116 of the needle valve 3108 than the resin α, and maintains a flow rate. Therefore, in the resin flow path 3206 where the dissolved resin α and the dissolved resin β merge, there is a difference in the flow rate of the dissolved resin α and the dissolved resin β, and the faster dissolved resin β flows to the outlet pipe (not shown). The dissolved resin α stays in the flow paths 3204 and 3205 in the adapter 3107.

  The retained dissolved resin deteriorates due to heat or the like, becomes a deteriorated resin, and when mixed into the product, it causes the appearance, mechanical characteristics, etc. of the product. The change of the type of resin is switched by extruding the resin remaining in the flow path with a resin that changes. However, if the staying resin remains in the above-mentioned 3204 and 3205, the amount of the extruded resin increases and a switching loss occurs.

JP 2005-1283 A

  An object of the present invention is to reduce the deteriorated resin. More specifically, by suppressing a decrease in flow rate of the dissolved resin α flowing in the vicinity of the valve stem of the dissolved resin needle valve 1108, the dissolved resin α and the resin in the resin path 1206 where the dissolved resin α and the dissolved resin β merge. The flow rate difference of the dissolved resin β is eliminated, the flow of the dissolved resin α and the dissolved resin β becomes smooth, the staying resin in the adapter 1107 with the back pressure adjusting device by the needle valve 1108 is reduced, and the deteriorated resin caused by the staying resin. Reduce.

  The object of the present invention is achieved by making the cross-sectional shape of the needle valve 1108 in the axial direction of the valve stem in the adapter 1107 with the back pressure adjusting device.

In the needle valve 1108 according to the present invention, the diameter of the needle valve valve body and the major axis ratio of the valve stem are preferably 1, and the minor axis ratio to the major axis of the valve stem is preferably 0.7 or less.
Further, it is preferable to attach the long axis of the cross-sectional shape perpendicular to the valve stem axis direction of the needle valve 1108 in parallel with the in-adapter flow path 1206 orthogonal to the concentricity of the screw 1102.

According to the present invention, by making the cross-sectional shape perpendicular to the axial direction of the valve stem of the needle valve 1108 elliptical, it is possible to suppress the difference in flow rate of the molten resin in the vicinity of the valve stem of the needle valve 1108. Further, if the ratio of the diameter of the valve body of the needle valve 1108 to the major axis of the valve stem is 1 and the length ratio of the minor axis to the major axis of the valve stem is 0.7 or less, the needle valve The difference in flow rate of the dissolved resin 1108 can be suppressed. Further, by attaching a long axis having a cross-sectional shape perpendicular to the valve stem axis direction of the needle valve 1108 in parallel to the flow path 1206 in the adapter 1107 perpendicular to the concentricity of the screw 1102, the difference in flow rate of the dissolved resin of the needle valve 1108 is further increased. Can be suppressed. By these, the resin flow in the adapter 1107 becomes smooth, and by reducing the staying resin, it becomes possible to reduce the deteriorated resin caused by the staying resin.
Further, since the staying resin in the flow path is reduced, the amount of extruded resin due to the resin change is reduced, and the switching loss is reduced.

Cross-sectional view of adapter with back pressure adjusting device according to the present invention Adapter sectional view having a back pressure adjusting device using an orifice Conventional adapter with back pressure regulator using needle valve Needle valve part diagram in conventional back pressure regulator Detailed view of the flow path near the needle valve in FIG. Needle valve site diagram according to the present invention AA sectional view in FIG. Detailed view of the flow path near the needle valve in FIG.

  In the present invention, the cross-sectional shape perpendicular to the axial direction of the valve rod of the needle valve 1108 between the horizontal flow path 1202 in the adapter 1107 and the flow path 1206 orthogonal thereto is modified to an elliptical shape, This is to reduce the deterioration resin by smoothing the flow of the dissolved resin and reducing the residence of the dissolved resin.

  First, the shape of the needle valve 1108 according to the present invention will be described.

FIG. 6 shows a needle valve 1108 according to the present invention. The needle valve 1108 includes a valve body 1117 and a valve rod 1116. The valve stem 1116 has a cross-sectional shape perpendicular to the axial direction, which is divided into an elliptical portion 1116b and a circular portion 1116a as shown in FIG. The valve stem 1116a is threaded like a bolt on a cylinder. The ellipse having a cross-sectional shape perpendicular to the axial direction of the valve stem 1116b has a major axis length equal to or less than the diameter of the valve body, and the ellipse minor axis to major axis ratio is less than 1. More preferably, the minor axis ratio to the major axis is in the range of 0.7 to 0.4, and even more preferably, the minor axis ratio to the major axis is from 0.5 to 0.4. When the area in contact with the dissolved resin is smaller, the deteriorated resin is hardly generated. However, when the ratio of the minor axis to the major axis is greater than 0.7, the deterioration of the deteriorated resin is not observed. Further, when the ratio of the minor axis to the major axis was 0.4 and 0.5, there was no significant difference in the decrease in the deteriorated resin. If the ratio of the minor axis to the major axis is less than 0.4, the strength tends to decrease. The valve body 1117 has a conical shape. The valve body 1117 and the valve stem 1116b have an elliptical long and short axis intersection in a range that is 1/3 of the radius away from the center of the circle that is the bottom surface of the valve body 1117, and the valve body This is a relationship in which an elliptical arc always exists inside the circle which is the bottom surface of 1117. More preferably, the intersection of the major axis and the minor axis of the ellipse exists in a range in which the length of 1/5 of the radius is separated from the center of the circle which is the cross section of the valve body 1117, and more preferably This is when the major axis or minor axis of the ellipse that is the cross section of the valve stem 1116b is symmetric with respect to the center line of the circle that is the cross section of the body 1117. If the valve stem 1116b is not in a symmetrical position with respect to the valve body 1117, a wide flow path and a narrow flow path are formed in the flow path, which causes a difference in flow velocity. In addition, when the valve body 1117 and the valve rod 1116b are in a range separated from the center of the circle, which is the bottom surface of the valve body 1117, by a length equal to or longer than the length of the radius ３, the deterioration of the deteriorated resin is not observed.
The valve body 1117 is moved by translating (moving non-rotatingly) the needle valve 1108, and the volume of the resin flow path is changed.

  Next, the adapter 1107 will be described.

  In FIG. 1, a screw 1102 is installed in a cylinder 1101, and there is a filtration device 1103 to which a breaker plate 1106 that supports a screen and a screen mesh is attached downstream of the cylinder 1101, and downstream of the filtration device 1103. An adapter 1107 is attached. The flow path 1202 in the adapter 1107 is also orthogonal to the flow path 1206 in the adapter 1107, and the downstream side is connected in the order of the outlet pipe 1105 and a die (not shown).

  Behind the cylinder 1101 is connected to a driven gear in a gear box (not shown) as a transmission. The driven gear is meshed with a drive gear connected to a rotating shaft of an electric motor (not shown) as a drive source of the screw 1102. Thereby, the rotation of the rotating shaft of the electric motor is decelerated and transmitted to the driven gear, and the screw 1102 is rotated.

  The back pressure adjusting device will be described.

  In FIG. 1, reference numeral 1107 denotes an adapter having a back pressure adjusting device 1104 attached to the side opposite to the flow path 1202, and the molten resin extruded from the tip of the cylinder 1101 circulates therethrough. The needle valve 1108 is installed between the horizontal channel 1202 and the orthogonal channel 1206 in order to adjust the resistance applied to the dissolved resin. The needle valve 1108 adjusts the dynamic pressure of the dissolved resin by adjusting the resistance applied to the dissolved resin that is pushed out from the tip of the cylinder 1101 by the screw 1102 and flows through the resin flow path 1203. The back pressure applied to the screw 1102 is adjusted. Reference numeral 1111 denotes a seal member for preventing the dissolved resin from leaking from the gap between the insertion hole of the closing member 1109 and the outer periphery of the needle valve 1108, and is fixed by a seal pressing member 1112.

  An example of a method for attaching the needle valve 1108 will be described. The needle valve 1108 is inserted into the adapter 1107. At that time, the cross section perpendicular to the axial direction of the valve stem of the needle valve 1108 is elliptical, and its long axis is inserted in a direction parallel to the adapter flow path 1206. By doing so, it is possible to reduce the area in contact with the horizontal direction of the valve stem of the needle valve that hinders the flow in the resin flow direction, and to further reduce the flow rate difference of the resin. As a result, the deteriorated resin can be further reduced. After the needle valve 1108 is inserted, the nut member 1113 is screwed into the threaded portion of the needle valve 1108. Next, the nut pressing plate 1114 is screwed to the support member 1110 with a bolt. By fixing the nut member 1113 connected to the needle valve 1108 with the pressing plate 1114, the needle valve 1108 is fixed so as not to move. The back pressure adjusting device 1104 is performed by changing the volume of the resin flow path 1203 by translating the needle valve 1108 in a non-rotating manner and adjusting the resistance applied to the dissolved resin.

  The flow of the resin will be described.

  The resin is supplied to the cylinder 1101 from a hopper (not shown), and the solid phase raw material resin is rotated by the screw 1102 and is kneaded while being conveyed toward the front of the cylinder 1101. And discharged from the front end of the cylinder 1101 to the flow path 1201. Then, the dissolved resin enters the flow path 1202 concentric with the screw 1102 in the adapter 1107 from the flow path 1201 through the breaker plate 1106. A lead-out pipe 1105 connected to a die (not shown) from the flow path 1202 through the flow path 1203 along the valve body of the needle valve 1108, through the flow path 1206 in the adapter 1107 orthogonal to the screw 1102 concentricity. To flow.

  The flow of resin in the adapter 1107 in the present invention will be described in detail.

  The dissolved resin passing through the resin flow path 1203 is the same as the adapter with a back pressure adjusting device using a conventional needle valve, as shown in FIG. 8, and the dissolved resin α passing above the needle valve 1108 and the needle valve 1108. It is distinguished by dissolved resin β that passes through the lower side. The dissolved resin α flows while contacting the valve rod 1116b of the needle valve 1108 in the circumferential direction. Since the cross-sectional shape perpendicular to the axial direction of the needle valve 1108 according to the present invention is an ellipse, the dissolved resin and the needle valve 1108 are compared to the conventional needle valve in which the cross-sectional shape perpendicular to the axial direction of the conventional valve stem is a circle. The contact area of the valve stem is reduced. Therefore, a decrease in the flow rate of the melted resin α in the vicinity of the valve rod 1116b of the needle valve 1108 can be suppressed from the conventional product, that is, a needle valve having a circular cross-sectional shape perpendicular to the axial direction. By suppressing a decrease in the flow rate of the dissolved resin α, the difference in flow rate between the dissolved resin α and the dissolved resin β is reduced in the in-adapter flow path 1206 where the dissolved resin α and the dissolved resin β merge. In both cases, the flow in the adapter internal flow path 1206 becomes smooth, and the staying resin in the adapter internal flow paths 1204 and 1205 decreases. By reducing the staying resin, it is possible to reduce the deteriorated resin resulting therefrom. Furthermore, by reducing the length ratio of the minor axis to the length of the major axis of the ellipse, the contact area between the melted resin and the valve stem of the needle valve is reduced, and the flow rate difference between the melted resin α and the melted resin β is further reduced. This can reduce the deteriorated resin. Further, since the staying resin in the adapter flow paths 1204 and 1205 is reduced, the amount of the extruded resin due to the resin change is reduced, and the switching loss is reduced.

  As for the mechanism for translating the needle valve 1108, a linear motion carriage is attached to the needle valve 1108, and a drive member such as a gear is provided so that the carriage moves linearly. The needle valve 1108 is translated and inserted by an actuator, a handle, etc. The length may be adjustable. Further, a control device that feeds back the insertion length of the needle valve 1108 with the measurement pressure of the resin using a resin pressure gauge may be used.

  The operation in the present invention will be described.

Coating is performed under the condition of extruding a constant amount of resin per hour, and a deteriorated resin of 0.2 mm or more is counted with a laser inspection device every 1000 m ² . The major axis of the valve stem of the needle valve is fixed at the same length as the diameter of the valve body of the needle valve, and the length of the minor axis is changed.
As a result, the cross-sectional shape perpendicular to the axial direction of the valve stem of the conventional needle valve is a circle, that is, the ratio of the number of deteriorated resins per 1000 m ² when the ratio of the major axis to the minor axis is 1: 1. Then, the cross-sectional shape perpendicular to the axial direction of the valve stem is elliptical, and the ratio of the number of deteriorated resins when using a needle valve whose major axis to minor axis ratio is 10: 7 is 0.84, It improves. More preferably, when a needle valve having an elliptical cross-sectional shape perpendicular to the axial direction of the valve stem and having a major axis / minor axis ratio of 2: 1 is used, the ratio of the number of deteriorated resins is 0.73. Thus, further generation of deteriorated resin can be suppressed. As described above, the present invention can suppress the deteriorated resin.

1101 Cylinder 1102 Screw 1103 Filtration device 1104 Back pressure adjustment device 1105 Outlet tube 1106 Breaker plate 1107 Adapter 1108 Needle valve 1109 Closure member 1110 Support member 1111 Seal member 1112 Seal retainer 1113 Nut member 1114 Nut retainer plate 1116 Valve rod 1117 Valve body 1201 In-cylinder flow path 1202 In-adapter flow path 1203 In-adapter flow path 1204 In-adapter flow path 1205 In-adapter flow path 1206 In-adapter flow path 2107 Adapter 2118 having a back pressure adjustment device Movable block 2119 Fixed block 3104 Back pressure adjustment device 3107 Adapter 3108 Needle valve

Claims (3)

  An adapter with a back pressure adjusting device disposed in the middle of a resin flow path through which melted resin that is kneaded and extruded from an extruder screw circulates, and has an elliptical cross-sectional shape perpendicular to the valve stem axis direction of the needle valve An adapter with a back pressure adjusting device.   2. The adapter with a back pressure adjusting device according to claim 1, wherein a ratio of a major axis of the needle valve valve body to a major axis of the valve stem is 1 and a ratio of a minor axis to a major axis of the valve stem is 0.7 or less.   The adapter with a back pressure adjusting device according to claim 1 or 2, wherein a long axis having a cross-sectional shape perpendicular to the valve stem axis direction of the needle valve is attached in parallel to the in-adapter flow path 1206 orthogonal to the concentricity of the screw.

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