JP2008012821A - Extrusion molding apparatus for plastic multilayer pipe - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable each of an inside pipe and an outside pipe of a multilayer pipe to have a desired quality and a desired precision, when forming the inside pipe and the outside pipe of the multilayer pipe by thermally melting different kinds of first and second resins. <P>SOLUTION: An extrusion molding apparatus 1 is provided with first and second extruding machines 10 and 11 for extruding the mutually different kinds of first and second resins; a die 12 in which an inside path 31 for enabling to form the inside pipe 4 by passing the first resin 8 and an outside path 37 for enabling to form the outside pipe 5 to be fitted onto the inside pipe 4 by passing the second resin 9, and which makes it possible to form the multilayer pipe 2 from the inner and outer side pipes 4 and 5; and a heater 13 for heating the die 12. The heater 13 is provided with a first heater 42 for heating a part 12a of the die 12, where at least a part of the inside path 31 is formed, and a second heater 43 for heating another part 12b of the die 12, where at least a part of the outside path 37 is formed, separately from the first heater 42. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an apparatus for extruding a resin multi-layer pipe, in which a multi-layer pipe is formed and an outer pipe can be molded, and each part of a die in which an outer passage is formed is heated separately from each other. It is.

  Conventionally, there is an apparatus for extruding a resin multilayer pipe as shown in Patent Document 1 below. According to this publication, the extruding device includes first and second extruders that extrude the first and second resins, which are different from each other, by thermally melting them separately, and the first and second extruders that are extruded from the first extruder. An inner passage is formed that allows the inner tube to be molded by allowing one resin to pass, and an outer tube that is externally fitted to the inner tube can be molded by passing the second resin extruded from the second extruder. An outer passage is formed, and includes a die capable of forming a multilayer tube by the inner and outer tubes, and a heater for heating the die.

  When the multilayer pipe is formed by the extrusion apparatus, the first and second resins heated and melted by the first and second extruders are continuously directed toward the upstream end of the inner and outer passages in the die. Extruded. Then, the first and second resins are passed through the inner and outer passages toward the downstream end thereof, thereby forming the inner and outer tubes. Next, the inner and outer tubes are integrally fitted to each other by the die and continuously extruded from the die, thereby forming a target multilayer tube.

During the formation of the multilayer pipe, the heater heats the die to heat and melt the first and second resins passing through the inner and outer passages, and to give them proper fluidity. .
Japanese Patent No. 3514739

  By the way, if the flow of the first and second resins melted by the heating is made laminar in the inner and outer passages, the inner and outer tubes have particularly high thickness dimensions. It is thought that it is formed, that is, a highly accurate multilayer tube is formed.

  However, in the above-described conventional technique, each of the “appropriate melting temperatures” for causing the first and second resins to flow in a more laminar flow and to bring them into an appropriate molten state is the first one. The second resin is different. On the other hand, the heater in the above prior art simply heats the die as a whole. For this reason, it is difficult to make each of the first and second resins have the “appropriate melting temperatures” in the conventional technique.

  Therefore, conventionally, as a first point, when the multilayer pipe is formed, the first and second resins are adjusted so that the “appropriate melting temperatures” of the first and second resins are close to each other. It has been broken. In addition, or together with this, as a second point, the temperature of the first and second resins passing through the inner and outer passages is almost equal to each “appropriate melting temperature” of the first and second resins. Heating is performed by the heater so as to be an average value or to match the value of “appropriate melting temperature” on the higher side than the average value.

  However, in the case of the first point, the degree of freedom in selecting the types of the first and second resins that are the materials of the inner and outer tubes tends to be reduced. In the case of the second point, the temperatures of the first and second resins cannot be brought close to the “appropriate melting temperature” with high accuracy. The flow of one of the second resins is slowed down by the high viscosity based on the excessively low temperature, and the flow of the other resin becomes turbulent due to the low viscosity based on the excessively high temperature. Accuracy tends to decrease.

  Therefore, in the above conventional technique, there is a problem that it is difficult to make the outer and inner tubes of the multilayer tube each have a desired material and desired accuracy.

  The present invention has been made paying attention to the above-described circumstances, and an object of the present invention is to thermally melt different types of first and second resins to form inner and outer tubes, and to In the case of forming a multi-layer tube by using a tube, the outer tube and the outer tube of the multi-layer tube can be made of a desired material and a desired accuracy.

According to the first aspect of the present invention, the first and second extruders 10 and 11 for extruding the first and second resins 8 and 9 of different types from each other are thermally melted separately and extruded from the first extruder 10. An inner passage 31 that allows the inner tube 4 to be molded by allowing the first resin 8 to pass therethrough is formed, and the second resin 9 extruded from the second extruder 11 is allowed to pass through and fitted to the inner tube 4. The outer passage 37 is formed to allow the outer tube 5 to be formed, and includes the die 12 capable of forming the multilayer tube 2 by the inner and outer tubes 4 and 5 and the heater 13 for heating the die 12. In the extrusion equipment for resin multilayer pipes,
The heater 13 includes a first heater 42 that heats a portion 12 of the die 12 in which at least a portion of the inner passage 31 is formed, and another portion 12b of the die 12 in which at least a portion of the outer passage 37 is formed. The first heater 42 includes a second heater 43 that is heated separately.

  In the invention of claim 2, in addition to the invention of claim 1, a heat insulating portion 48 is provided between the part 12a and the other part 12b of the die 12 to prevent heat transfer between the parts 12a and 12b. Is.

  According to the invention of claim 3, in addition to the invention of claim 1 or 2, the mating surface 47 of the part 12a and the other part 12b of the die 12 is formed on a surface orthogonal to the axis 22 of the die 12. The heat insulating portion 48 is interposed between the mating surfaces 47.

  In this section, the reference numerals appended to the above terms are not to be construed as limiting the technical scope of the present invention to the section “Example” described later or the contents of the drawings.

  The effects of the present invention are as follows.

According to the first aspect of the present invention, the first and second extruders for extruding the first and second resins, which are different from each other, are separately melted and extruded, and the first resin extruded from the first extruder is passed through. An inner passage is formed that allows the inner tube to be molded, and an outer passage is formed that allows the outer tube that is externally fitted to the inner tube to pass through the second resin extruded from the second extruder. In the extrusion apparatus for a resin multilayer pipe provided with a die capable of forming a multilayer pipe with the inner and outer pipes and a heater for heating the die,
A first heater that heats a portion of the die in which at least a portion of the inner passage is formed; and another portion of the die in which at least a portion of the outer passage is formed separately from the first heater. And a second heater for heating.

  For this reason, during the formation of the multilayer tube by the extrusion molding apparatus, the heater heats and melts the first and second resins passing through the inner and outer passages by heating the die, and imparts fluidity thereto. .

  A part of the die in which the inner passage is formed is heated by the first heater, and the temperature of the first resin passing through the inner passage is heated to the “appropriate melting temperature”. On the other hand, the other part of the die in which the outer passage is formed is heated by the second heater separately from the first heater, and the temperature in the case of the second resin 9 passing through the outer passage is the “ It is heated so as to have an “adequate melting temperature”.

  Therefore, even if the first and second resins are made of different materials, even if they are different from each other, the first and second resins are more reliably secured by the above-described separate heating. Each is brought to the “appropriate melting temperature”, and a more laminar flow is possible in the inner and outer passages. As a result, the inner and outer tubes are formed with higher accuracy, that is, the multilayer tube is formed with higher accuracy.

  According to a second aspect of the present invention, a heat insulating part for preventing heat transfer between the part and the other part of the die is interposed.

  For this reason, heat exchange between a part of the die and the other part is prevented by the heat insulating part, so that each temperature control between the part of the die and the other part prevents mutual thermal effects. , Each can be accurate.

  Therefore, the first resin in the inner passage formed in a part of the die and the second resin in the outer passage formed in the other part of the die can each be brought to a more “appropriate melting temperature”. As a result, the first and second resins can flow more reliably in a laminar flow, and the effect of claim 1 is promoted.

  According to a third aspect of the present invention, a mating surface between a part of the die and another part is formed on a surface orthogonal to the axial center of the die, and the heat insulating portion is interposed between the mating surfaces. .

  For this reason, the structure in which a part of the die, the other part, and the heat insulating part are linked to each other can be simplified. Therefore, these molding and assembling operations can be facilitated.

  The present invention relates to an apparatus for extruding a resin multi-layer pipe. When different types of first and second resins are heat-melted to form inner and outer pipes, the inner and outer pipes are used to form a multi-layer pipe. The best mode for carrying out the present invention is as follows in order to achieve the object of making the outer tube of the multilayer tube of the desired material and the desired accuracy.

  That is, the extrusion apparatus for the resin multilayer pipe includes the first and second extruders for extruding the first and second resins different from each other by heat melting separately, and the first extruded from the first extruder. An inner passage that allows the inner tube to be molded by allowing the resin to pass therethrough is formed, and an outer tube that is externally fitted to the inner tube can be molded by passing the second resin extruded from the second extruder. An outer passage is formed, and includes a die capable of forming a multilayer tube by the inner and outer tubes, and a heater for heating the die.

  A first heater that heats a portion of the die in which at least a portion of the inner passage is formed; and another portion of the die in which at least a portion of the outer passage is formed separately from the first heater. And a second heater for heating.

  In order to explain the present invention in more detail, an embodiment thereof will be described with reference to the accompanying drawings.

  In the figure, reference numeral 1 denotes an extrusion molding apparatus. This extrusion molding apparatus 1 has a multilayer pipe 2 made of resin and a metal core 3 housed in the multilayer pipe 2 facing forward indicated by an arrow Fr. Continuous extrusion molding is performed. The multilayer tube 2 includes a circular inner tube 4 and a circular outer tube 5 that is integrally fitted to the inner tube 4.

  The extrusion molding apparatus 1 is made of a thermoplastic first resin, first and second extruders 10 and 11 that are different from each other and are continuously melted and extruded separately separately. A die for continuously extruding the multilayer pipe 2 in which the first and second resins 8 and 9 extruded from the first and second extruders 10 and 11 are passed and the core material 3 is fitted therein. 12, a heater 13 for heating the die 12, a take-up machine (not shown) for taking up the multi-layer pipe 2 and the core material 3 extruded from the die 12, and the multi-layer pipe 2 between the die 12 and the take-up machine And a cooling device (not shown) for cooling the core material 3 to solidify the multilayer tube 2.

  The first resin 8 includes a plurality of (three) different first resins 8a, 8b, and 8c. The first extruder 10 also has a plurality (three) of first extruders 10a, 10b, and 10c. Each of the first extruders 10a, 10b, and 10c allows the first resins 8a, 8b, and 8c to be separately melted and extruded.

  The die 12 includes first to fifth die members 16-20 arranged in a row from the rear side toward the front side, and the first to fourth die members 16- on the axis 22 extending in the front-rear direction. 19 is provided with a mandrel 23 fitted into a die hole formed in 19 and a fastener 24 for detachably fixing the first to fifth die members 16-20 and the mandrel 23 to each other.

  The second die member 17 includes first to third cylindrical bodies 26-28 that are taper-fitted into a plurality of layers on the shaft center 22. The first to third cylindrical bodies 26 to 28 are sequentially arranged from the inner side to the outer side of the second die member 17.

  An inner passage 31 is formed in the die 12 so that the first resin 8 extruded from the first extruder 10 can pass therethrough and the inner tube 4 can be formed in the multilayer tube 2.

  Specifically, cylindrical first to third passages 32 that are independent from each other between the mandrel 23 and the first to third cylindrical bodies 26-28 in the orthogonal direction (radial direction) of the shaft center 22. -34 is formed. These first to third passages 32 to 34 form the rear portion of the inner passage 31. And each 1st resin 8a, 8b extruded from each 1st extruder 10a, 10b, 10c as mentioned above to each rear-end part (upstream end part) of the said 1st-3rd channel | path 32-34, respectively. 8c can be introduced.

  A cylindrical inner passage body 35 is formed between the mandrel 23 and the third die member 18 in the direction perpendicular to the axis 22. The inner passage body 35 forms a front portion of the inner passage 31. The front ends of the first to third passages 32-34 communicate with the rear end of the inner passage body 35 so as to gather together.

  On the other hand, an outer passage 37 that allows the outer tube 5 to be formed in the multilayer tube 2 by passing the second resin 9 extruded from the second extruder 11 is formed in the die 12. Specifically, in the direction perpendicular to the axis 22, a frustoconical cylindrical outer passage 37 is formed between the third and fourth die members 18, 19 so that the radial dimension decreases toward the front. .

  A cylindrical joining passage 38 is formed between the mandrel 23 and the fifth die member 20 in the direction orthogonal to the axis 22. The front end of the inner passage body 35 of the inner passage 31 and the front end of the outer passage 37 are communicated with the rear end of the junction passage 38 so as to gather together. The front end of the merge passage 38 is opened forward from the front surface of the fifth die member 20.

  On the shaft 22, a through hole 40 is formed in the mandrel 23, and the core material 3 can be inserted forward through the through hole 40.

  The heater 13 includes a first heater 42 that heats a portion 12a of the die 12 in which the first to third passages 32-34 that are at least a part of the inner passage 31 are formed, and at least the outer passage 37. A second heater 43 that heats the other part 12 b of the die 12 that is partially formed separately from the first heater 42 is provided.

  A part 12 a of the die 12 corresponds to the second die member 17 and a rear portion of the mandrel 23 fitted in the second die member 17. The first heater 42 is inserted into the external heater 45 that heats the second die member 17 from the outer surface side and the through hole 40, and is attached to the second die member 17 in the axial direction of the die 12. And an internal heater 46 for heating the corresponding mandrel 23 from the inner surface side. On the other hand, the other part 12b of the die 12 corresponds to the third to fifth die members 18-20. And the said 2nd heater 43 heats the 3rd-5th die member 18-20 from the outer surface side. The internal heater 46 heats the mandrel 23 where the inner passage body 35 is formed.

  A mating surface 47 where the second die member 17 which is a part 12a of the die 12 and the third die member 18 which is the other part 12b face each other is formed on a surface orthogonal to the axis 22 of the die 12. ing. Between the mating surfaces 47, a heat insulating portion 48 for interposing heat between the part 12a and the other part 12b of the die 12 is interposed.

  The said heat insulation part 48 is demonstrated. An annular groove 49 centering on the axis 22 is formed on the mating surface 47 (front surface) of the second die member 17. On the other hand, on the mating surface 47 (rear surface) of the third die member 18 corresponding to the annular groove 49, a plurality (three) of annular cooling grooves 50 centering on the shaft center 22 are formed. These cooling grooves 50 are formed by bending one groove. A lid plate 52 is provided which is fixed to the mating surface 47 (rear surface) of the third die member 18 by a fastener 51 and uses the cooling groove 50 as a sealed passage. Communication passages 53 and 54 are formed for opening each end of the cooling groove 50 to the outside of the third die member 18. The lid plate 52 is formed of a metal plate, but may be formed of a heat insulating material such as ceramic.

  An air pump 56 is provided for supplying cooling air 55 to one end of the cooling groove 50 through one of the communication passages 53, 54. The air 55 supplied to one end of the cooling groove 50 flows through the cooling groove 50, reaches the other end, and is discharged to the outside of the third die member 18 through the other communication path 54. The heat exchange between the second and third die members 17 and 18 and the air 55 insulates the part 12a and the other part 12b of the die 12 from each other.

  When the multilayer pipe 2 is formed by the extrusion molding apparatus 1, the first and second extruders 10 and 11 and the take-up machine are driven, and the die 12 is heated by the heater 13. The first resins 8a, 8b, 8c extruded by driving the first extruders 10a, 10b, 10c sequentially pass the first to third passages 32-34 and the inner passage body 35 of the inner passage 31. Through this, the multilayered (three layers) inner tube 4 is formed. On the other hand, the second resin 9 extruded by driving the second extruder 11 is passed through the outer passage 37, whereby the outer pipe 5 is formed.

  Next, the inner tube 4 and the outer tube 5 are passed through the joining passage 38, whereby the multilayer tube 2 is formed. A tensile stress is generated in the multilayer pipe 2 by the pulling force of the take-up machine, and the pipe is contracted in the radial direction and is externally fitted so as to be in close contact with the core material 3. Thereafter, the multilayer tube 2 and the core material 3 are cooled, and the multilayer tube 2 as the final product is formed.

  During the formation of the multilayer tube 2, the heater 13 heats the die 12 to heat and melt the first and second resins 8 and 9 passing through the inner and outer passages 31 and 37. It is supposed to give liquidity.

  In each of the inner and outer passages 31 and 37, the first and second resins 8 and 9 are made to flow in a laminar flow, and each “appropriate melting temperature for making them into an appropriate molten state”. "Is greatly different for each of the first and second resins 8 and 9. The “appropriate melting temperatures” of the first resins 8a, 8b, and 8c are substantially the same.

  More specifically, the first resin 8 is an acrylic resin, and the “appropriate melting temperature” is 230 ° C. ± 10 ° C. On the other hand, the second resin 9 is a vinyl chloride resin, and its “appropriate melting temperature” is 160 ° C. ± 5 ° C. The difference between these “appropriate melting temperatures” is 50 ° C. or more, which is a large difference. For this reason, the part 12a of the die 12 in which the inner passage 31 is formed is heated to be higher in temperature than the other part 12b of the die 12 in which the outer passage 37 is formed, so that the first and second resins are formed. 8 and 9 are each controlled to be more “appropriate melting temperature”. Such temperature control is achieved by a temperature sensor (not shown) or a control device (not shown) that electronically controls the heater 13 based on detection signals of these sensors.

  Each material of the first resin 8 and the second resin 9 may be reversed from the above, and in this case, the outer passage is more than the part 12a of the die 12 in which the inner passage 31 is formed. The other part 12b of the die 12 in which 37 is formed is heated to a high temperature.

  The portion 12a of the die 12 in which the inner passage 31 is formed is heated by the first heater 42 so that the temperature of the first resin 8 passing through the inner passage 31 becomes the “appropriate melting temperature”. Heated. Meanwhile, the other portion 12 b of the die 12 in which the outer passage 37 is formed is heated by the second heater 43 separately from the first heater 42, and the temperature of the second resin 9 passing through the outer passage 37. Is heated to the “appropriate melting temperature”.

  Therefore, even if the first and second resins 8 and 9 are made of desired materials, the first and second resins 8 and 9 are different from each other. By heating separately from each other, it is possible to more surely reach the “appropriate melting temperature”, and a more laminar flow is possible in the inner and outer passages 31 and 37. As a result, the inner and outer tubes 4 and 5 are formed with higher accuracy, that is, the multilayer tube 2 is formed with higher accuracy.

  Further, as described above, the heat insulating portion 48 is provided between the part 12a and the other part 12b of the die 12 to prevent the heat transfer between the parts 12a and 12b.

  For this reason, heat exchange between the portion 12a and the other portion 12b of the die 12 is prevented by the heat insulating portion 48. Therefore, the temperature control of the portion 12a and the other portion 12b of the die 12 is mutually controlled. While preventing the heat effect of each, it is possible to accurately each.

  Therefore, the first resin 8 in the inner passage 31 formed in the portion 12a of the die 12 and the second resin 9 in the outer passage 37 formed in the other portion 12b of the die 12 are each more “appropriate melting temperature”. Can be made. As a result, the first and second resins 8 and 9 can flow more reliably in a laminar flow.

  Further, as described above, the mating surface 47 of the part 12 a and the other part 12 b of the die 12 is formed on a surface orthogonal to the axis 22 of the die 12, and the heat insulating portion is interposed between the mating surfaces 47. 48 is interposed.

  For this reason, the structure in which the part 12a, the other part 12b, and the heat insulating part 48 of the die 12 are linked to each other can be simplified. Therefore, the molding and assembling work of these 12a, 12b, and 48 can be facilitated.

  Although the above is based on the illustrated example, the inner passage 31 may be single, and the outer passage 37 may have a plurality of passages like the illustrated inner passage 31. Further, when the values of the “appropriate melting temperatures” of the first resins 8a, 8b, and 8c are greatly different from each other, such as 50 ° C. or more, another heat insulation is provided between the first to third passages 32-34. The part 48 may be provided.

  In the illustrated example, only the rear portion of the inner passage 31 is formed in the portion 12 a of the die 12. However, almost the entire inner passage 31 may be formed in the portion 12 a of the die 12. .

It is side surface sectional drawing of an extrusion molding apparatus. It is the elements on larger scale of FIG. FIG. 3 is a partial cutaway view taken along line III-III in FIG. 1.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Extrusion molding apparatus 2 Multilayer pipe 4 Inner pipe 5 Outer pipe 8 1st resin 9 2nd resin 10 1st extruder 11 2nd extruder 12 Die 12
12a Part 12b Other part 13 Heater 22 Axle 31 Inner passage 37 Outer passage 38 Merge passage 42 First heater 43 Second heater 48 Heat insulation part

Claims (3)

The first and second extruders, which are different from each other, are melted and extruded separately, and the first resin extruded from the first extruder is passed through to allow the inner tube to be molded. An inner passage is formed, and an outer passage is formed that allows the second resin extruded from the second extruder to pass therethrough to form an outer tube that is externally fitted to the inner tube. In a resin multilayer tube extrusion molding apparatus comprising a die capable of forming a multilayer tube and a heater for heating the die,
A first heater that heats a portion of the die in which at least a portion of the inner passage is formed; and another portion of the die in which at least a portion of the outer passage is formed separately from the first heater. A resin multilayer pipe extrusion molding apparatus comprising a second heater for heating.   The apparatus for extruding a resin multilayer pipe according to claim 1, wherein a heat insulating part for preventing heat transfer between the part and the other part of the die is interposed.   The mating surface of a part of the die and another part is formed on a surface orthogonal to the axial center of the die, and the heat insulating portion is interposed between the mating surfaces. Or the extrusion molding apparatus of the resin multilayer pipe | tube of 2.

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