JP2923853B2 - Extrusion method and extrusion equipment for heterogeneous multilayer pipe - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for extruding a heterogeneous multi-layered tube for simultaneously molding integrally a rubber and a thermoplastic synthetic resin having greatly different extrusion temperatures.

[0002]

2. Description of the Related Art A flexible tube generally called a hose is made by extruding rubber or synthetic resin. In order to enhance the oil resistance, gasoline resistance, gas permeation resistance, etc. of the hose, the outer layer is made of rubber and the inner layer is made of synthetic resin according to the purpose. As an example of the prior art,
FIG. 4 shows a process for manufacturing a heterogeneous multilayer pipe in which the inner layer is a synthetic resin having a thickness of about 0.02 to 0.2 mm and the outer layer is a rubber having a thickness of 1 to 4 mm.
(A) and (B). (A) is a first step, and (B) is a second step. Long core material (mandrel) in the first step
Is wound with a synthetic resin layer covered thereon, and in a second step, a rubber layer is covered thereon and wound. This is put into a kettle, vulcanized, and then the core material is removed.

[0003] Reference numeral 1 in FIG. 4 (A) is a core material feeder. Since this core material forms the inner surface of the tube, the uniformity of the outer diameter in the longitudinal direction, roundness, and surface roughness are reduced. Strict, high heat-softening points, and sufficient tensile strength must be provided for the number of types of inner diameter dimensions of the product. Moreover, it is a troublesome core material (not necessary in the present invention) that uses nerves to prevent surface scratches during handling. Now, after passing through the feeder 2 of FIG. 4 (A), the core material is coated with a release agent that makes it easy to peel off the multi-layer tube covering the core material while passing through the release agent applicator 3,
The synthetic resin layer can be covered by a resin extruder 4 having a cross head with a gear pump. The core material C is provided below the core material feeder 1.
And a cross section of a core material C in which a synthetic resin P is covered below the extruder 4. In FIG. 4A, 5 is a mist-type cooling tank, 6 is a take-up machine, and 7 is a winder.

In FIG. 4B showing the second step, reference numeral 8 denotes a feeder, 9 denotes a feeder, 10 denotes a rubber extruder having a crosshead, and a core material C having a rubber G applied to an outer layer below the extruder. 2 shows a cross section of FIG. 11 is a cooling water tank, 12 is a take-up machine, and 13 is a winding machine. The subsequent steps are (powder) → (winding) →
(Vulcan vulcanization) → (pulling core material) → (cutting), but if necessary, an adhesive layer is provided on the outer rubber layer before vulcanization to provide a reinforcing braid or spiral. In some cases, vulcanization is performed after a blade is formed, and the outside is further covered with rubber.

[0005]

A two-layer tube can be made with a conventional two-layer co-extrusion head even if the type is different between rubber and rubber, or resin and resin. FIG. 5 is an explanatory view of an extrusion head for making a two-layer tube by stacking two kinds of synthetic resins, and FIG. 6 is a production drawing of a tip of an extrusion head for making a two-layer tube with two kinds of rubber. The resin A entering from the right entrance in FIG. 5 moves leftward along the outer peripheral passage a of the spindle-shaped inner guide member 40 and exits into the gap between the nipple 41 and the die 42. The resin B entered from the lower entrance of FIG. 5 passes through the passage b in the gap between the intermediate die 43 surrounding the outer periphery of the passage a and the exit die 42, and overlaps the resin B coming from the passage a near the exit. It is extruded together as a two-layer tube from between the exit die 42 and the nipple 41. Reference numeral 44 denotes an air inlet for internal pressure for making the extruded double-layer pipe a perfect circle.

FIG. 6 shows only a tip portion of an extrusion head in which a two-layer tube is formed using two types of rubbers A 'and B'. The rubbers A 'and B' travel along the paths a 'and b', respectively. The rubber A 'is wrapped in the rubber B' of the passage b 'coming out of the gap between the intermediate die 43 and the exit die 42 when the passage a' comes out of the gap between the nipple 41 and the intermediate die 43, and has two layers. Go to the exit as a tube. A temperature control jacket 45 surrounds the entire extrusion head to circulate cold or hot water. The extrusion head for synthetic resin shown in FIG.
An electric heating band (not shown) is wound on the entire peripheral surface to maintain the temperature at 400 ° C. Temperature control is an important control item.

Since the extrusion temperature of rubber is between 40 ° C. and 120 ° C., the difference between the extrusion temperature of rubber and the resin is generally about 10 ° C.
There are also 0 ° C or higher. Therefore, both are sent to the extrusion head of FIG. 5 or 6 and extruded at the respective required molding temperatures.
It is obviously impossible to integrate them as inner and outer layers. For that reason, as described above, it was necessary to use a complicated and expensive manufacturing method. SUMMARY OF THE INVENTION The present invention has dared to address the difficult problem of simultaneously forming a multi-layer pipe made of a plurality of materials having significantly different extrusion temperatures, similarly to conventional multi-layer pipes.

[0008]

As a result of research, the present invention has ensured that the extrusion temperature of both materials can be maintained by completely separating the passage to the outlet of the inner and outer layer materials. Then, both material outlets are separated, and at the position where the rubber in the outer layer comes out of the outlet and the expansion due to the reduced pressure is finished, the synthetic resin which is higher than 100 ° C. or more is sprayed from the outlet inserted into the inner circumference of the rubber. To be extruded. Thus, the difficult problem of extruding different types of rubber and resin multi-layer tubes at once can be solved.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The method for extruding a heterogeneous multi-layer pipe according to the present invention is a method of simultaneously molding a multi-layer pipe using rubber for an outer layer and a synthetic resin for an inner layer by an extruder. When extruded into a tube, the outlet of the tip of the synthetic resin extrusion head is inserted into a position surrounded by the inner periphery of the rubber, and during the extrusion of the tubular rubber, the synthetic resin is extruded from the synthetic resin extrusion head into the tubular rubber. It is characterized in that it is extruded radially so as to be pressed against the inner periphery to form an inner layer tube.

The apparatus for extruding a heterogeneous multi-layer pipe according to the present invention is an apparatus for simultaneously and integrally molding a multi-layer pipe using rubber for an outer layer and synthetic resin for an inner layer by an extruder. The extrusion head is equipped with a nipple and a die for extruding a rubber tube of the required dimensions and a synthetic resin tube that forms the inner layer, a nipple for the synthetic resin tube, a nipple for the rubber tube at the tip of the die, and a central portion of the die penetrating in the extrusion direction. Then, the extruded rubber tube is inserted into the position surrounded by the inner periphery, and the synthetic resin outlet at the tip of the extruded rubber tube spreads diagonally outward in the extrusion direction, and the extruded synthetic resin is It is characterized by being pressed against the inner circumference of the rubber tube.

The nipple for a synthetic resin pipe of the above-mentioned extruder has a spout at the end thereof, and the spout is for sending out a gas having a pressure effective for bringing the synthetic resin pipe into close contact with a rubber pipe on the outer periphery. If so, the joining of the inner and outer layers becomes more reliable.

[0012] At least one of the rubber pipe and the synthetic resin pipe nipple and die of the above-mentioned extruder is a multi-layer nipple for simultaneously forming the same kind of multilayer pipe, and a three-layer pipe when the die is formed.
A four-layer tube can be easily manufactured.

[0013]

FIG. 1 shows an example of a production line for a heterogeneous multilayer pipe of rubber and synthetic resin to which the present invention is applied. Reference numeral 21 denotes a synthetic resin extruder, to which an extrusion head 21a having a nipple and a die is attached. This is a so-called straight head, which is directed in the extrusion direction (arrow t) of the multilayer pipe as a product. Reference numeral 22 in the figure denotes a rubber extruder, which is perpendicular to the extrusion direction t of the multilayer pipe as a product. The extrusion head 22a is a so-called crosshead, which is orthogonal to the direction of the rubber extruder 22 and opposite to the multilayer tube extrusion direction t. FIG. 1 encloses the vicinity of these two heads with a rectangular dashed line, and FIG. 2 is an enlarged cross-sectional view thereof. 1 is a well-known cooling water tank, 12 is a take-up machine, and 13 is a winder.

An embodiment of the present invention will be described below with reference to FIG. 2 and FIG. 3 which is an enlarged view of a main part thereof. FIG.
Reference numerals 3 to 3 denote embodiments in which the present invention is adopted most naturally, and the synthetic resin extruder 21 and its extrusion head 21a are oriented in the same direction as the extrusion direction t of the multilayer tube T to be molded. 21b is an extrusion cylinder, 21c is a screw, 21d is a heating part. The rubber extruder 22 is oriented in a direction perpendicular to the extrusion direction t of the multilayer tube T, and its extrusion head 22a initially advances the material rubber g in a direction opposite to the multilayer tube extrusion direction t, and then reverses near the outlet to extend the extrusion direction. A nipple 23 and a die 24 having a special shape to be provided as a tubular rubber G in the same direction as t are attached. The nipple usually forms the inner circumference of the tube, and the die forms the outer circumference. In this case, the reverse operation is performed because the raw rubber g is inverted. I do not stick to the name. 22b is a cylinder liner, 22c is a temperature control jacket.

In the case of multiple extrusion molding, the extruder for the outer layer is orthogonal to the extruder for the inner layer as shown in FIG.
It is common for the latter extrusion head to be a crosshead. However, the reason why the extrusion head 22a has a special shape in which the extrusion head 22a is not oriented in the extrusion direction t of the heterogeneous multi-layer pipe to be a product but is oriented in the opposite direction and is inverted near the outlet is that a resin is formed in the center of the rubber outlet. This is for receiving the nipple 25 of the extrusion head 21a and the tip end outlet of the die 26. It is a form that sticks out the mouth and accepts the other party's mouth. If the rubber extrusion head 22a is oriented in the extrusion direction t with common sense, it is difficult to maintain a high resin extrusion temperature even if the nipple 25 and the die 26 of the resin extrusion head 21a are elongated.

Although the enlarged FIG. 3 is easier to see, the nipple 23 and the die 24 on the rubber side surround the inside and outside of the material rubber g.
After turning in the direction opposite to the multilayer pipe extrusion direction t, the pipe is bent sharply, and the rubber outlet 27 is turned in the direction of t.
The tip of the die 24 inside the ring-shaped outlet 27 has a thin ring shape and forms an opening for receiving the ends of the resin-side nipple 25 and the die 26. Therefore, the rod-shaped tip of the resin-side nipple 25 and the cylindrical tip of the die 26 can be easily connected to the rubber-side die 24.
And the outlet 28 of the material resin P is located at a position further advanced in the extrusion direction than the rubber outlet 27. And the tip of the resin side nipple 25 spreads to the outer periphery,
The resin outlet 28 is spread obliquely outward in the extrusion direction t.

The material rubber g coming out of the rubber outlet 27 is several meters.
The expansion deformation due to the release from the pressure in the cylinder is completed during the advance of m, and a stable tubular rubber, that is, an outer rubber tube G is formed, and advances straight in the extrusion direction t. And several meters beyond the rubber outlet 27
m high-temperature resin P coming out from the resin outlet 28
Spreads out at the end, is pressed against the inner periphery of the stable rubber tube G, and joins to form an inner resin tube. The rubber-side extrusion head 22a holds the nipple 23 having a special shape with the nipple holder 32 and the core bar 33 (FIG. 2), and holds the die 24 with the die 29, the die holder 30, the flow guide 31, and the extrusion head 22a with the water-cooling jacket 22c. And so on.

As shown in FIG. 3, the resin-side extrusion head 21a is fixed by screwing the base 25a of the nipple 25 having a special shape into the tip of the nipple holder 34, and the nipple holder 34 is a radial leg that traverses the passage of the material resin P. The portion 34a is fitted in a concave portion of the main body of the head 21a, and the die 26 and the die 26 are fixed together by a die holder 36 via a flow guide 35 fitted in the same concave portion and the base 26a of the die 26.

In this embodiment, the nipple 25 for the synthetic resin tube of the inner layer has a spout 37 at its tip.
The holder 34, the air passage 38 in the main body of the extrusion head 21a, and the compressed air receiving port 39 communicate with a compressed air source (not shown). At the time of manufacturing a general plastic hose, compressed air is similarly sent into the pipe to maintain the roundness of the pipe, but it is a minute pressure enough to make the pipe round. In the case of the present invention, the internal pressure at which the inner layer resin pipe P and the outer layer rubber pipe G are joined to each other.
Air at a suitable pressure between

The embodiment of the different kind of multi-layer pipe in which the inner layer resin pipe P and the outer layer rubber pipe G are joined and integrated has been described above. For two or three layer head, for resin two or more
A three-layer head may be used. The design of the conventional multiple nipples and dies for forming the same type of multi-layer pipe of rubber or resin is changed. For rubber, it is easy to make the multiple rubber tubes go straight in the extrusion direction by turning them in the reverse direction like the nipple 23 and the die 24 in FIG. Multiple nipples and dies for resin have multiple outlets as shown in Fig. 3.
5. It is easy to change the design such that the rubber-side nipple is penetrated into the center of the die like the die 26, and the extruded multiple resin spreads out and joins to the rubber tube on the outer periphery. In addition, it goes without saying that the present invention can be variously changed and applied in accordance with the conditions of implementation and the ingenuity of the practitioner.

The synthetic resins and rubbers used in the present invention are described below. As the thermoplastic resin, tetrafluoroethylene (PTFE), tetrafluoroethylene
Fluoroalkyl vinyl ether copolymer (PFA),
Polyvinylidene fluoride (PVDF), tetrafluoroethylene-hexafluoropropylene-vinylidene fluoride copolymer (THV), tetrafluoroethylene-hexafluoropropylene mapoloma (FEP),
Tetrafluoroethylene-ethylene copolymer (ETF
E) and other fluororesins, nylon-6, nylon-
Resins currently commonly used for extrusion molding, such as polyamide resins such as 6,6, nylon-11 and nylon-12, and polyolefin resins such as polyethylene (PE) and polypropylene (PP) can be used. (The molding temperature is generally in the range of 150 to 400 ° C.)
NR, EPDM, IR, SBR, NBR, CR, CH
C, CSM, IIR, and other general rubbers generally subjected to extrusion molding, and thermoplastic elastomers (TPE) such as TPO can be targeted. (The molding temperature is generally in the range of 40 to 120 ° C for rubber, and is generally in the range of 150 to 250 ° C for TPE.)

[0022]

The present invention has succeeded for the first time in forming a heterogeneous multilayer pipe in which rubber and synthetic resin having different extrusion molding temperatures by 100 ° C. or more are integrated by simultaneous extrusion. Although the conventional two-layer tube is overlapped with two layers before exiting the extrusion head, the present invention first releases the relatively low temperature rubber to the outside air.
While traveling in the outside air by several mm, the rubber has completed expansion and deformation due to reduced pressure and proceeds in a stable state. Therefore, the resin is radially extruded outward from the resin outlet that has been inserted into the inner position. The high-temperature resin that has spread out is pressed and joined to the inner periphery of the rubber tube like spraying to form an inner layer of a heterogeneous multilayer tube.

That is, the present invention has solved the problem by a novel method in which a relatively low temperature rubber is discharged from an extrusion head and a high temperature synthetic resin is pressed at a stabilized place. Also disclosed is an apparatus suitable for an unprecedented configuration in which the resin-side nipple and the exit of the die are inserted into the rubber-side nipple and the die. Furthermore, in order to bond the resin of the inner layer to the rubber of the outer layer, it has been proposed to increase the internal pressure for maintaining a perfect circle of the conventional pipe to the internal pressure for bonding.

Further, the present invention provides two or three layers of one or both of a resin layer and a rubber layer of a heterogeneous multi-layer tube, so that the hose has mechanical strength, heat resistance, oil resistance, gasoline resistance and gas permeation resistance. To meet the demands of various functions such as characteristics, a wider range of functions can be developed than before by using multiple layers of different materials. This invention is ideal for the production of low pressure fuel hoses, evaporative hoses, and breather hoses used in the fuel piping system of automobiles for the time being, but it can improve the performance of various hoses and dramatically reduce the production cost. The effect of promoting the development and utilization of high-performance hoses in various areas is enormous.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a heterogeneous multilayer pipe production line to which the present invention is applied.

FIG. 2 is an enlarged cross-sectional view in a portion surrounded by a broken line in FIG.

FIG. 3 is an enlarged view of a main part of FIG. 2;

FIG. 4A is a first step partial explanatory view of a conventional heterogeneous multilayer pipe production line. (B) is a partially explanatory view of the second step.

FIG. 5 is an explanatory sectional view of a conventional extrusion head for a two-layer resin pipe.

FIG. 6 is a sectional view of a conventional extrusion head outlet portion for a two-layer rubber tube.

[Explanation of symbols]

 Reference Signs List 21 resin extruder 21a resin extrusion head 22 rubber extruder 22a rubber extrusion head 23 rubber nipple 24 rubber die 25 resin nipple 26 resin die g material rubber P material resin T heterogeneous multi-layer pipe

──────────────────────────────────────────────────続 き Continuation of the front page (51) Int.Cl. ⁶ Identification symbol FIB29L 23:00 (56) References JP-A-9-239807 (JP, A) JP-A-52-129765 (JP, A) JP-A-4-241926 (JP, A) JP-A-59-152828 (JP, A) JP-A-61-175015 (JP, A) JP-A-2-80427 (JP, U) JP-A-2-112417 (JP JP, U) Japanese Utility Model Hei 3-26525 (JP, U) (58) Fields surveyed (Int.Cl. ⁶ , DB name) B29C 47/00-47/96 B32B 1/08

Claims (1)

(57) [Claims] 1. An apparatus for simultaneously molding a rubber and a synthetic resin in a multilayer tube using an extruder and an extrusion head for a rubber and a synthetic resin, respectively. head is provided with a nipple for extruding a synthetic resin tube composed of its inner layer and the rubber tube of the required size, the die, the extruder and the extrusion head of the synthetic resin, a multilayer pipe extrusion direction
The rubber extruder and the extrusion head are provided in the same direction as the plastic resin extruder.
And a synthetic tree placed in the extrusion head
The extruder and extrusion head for fat are completely separated, and the extruder for rubber is arranged in a direction perpendicular to the extrusion direction of the multilayer tube.
And location, the extrusion head of the rubber is perpendicular to the direction of the extruder rubber
Orientation as a crosshead and push from the rubber extruder.
The extruded material rubber is first extruded in the direction opposite to the extrusion direction of the multilayer tube, and then the nipple for the inverted rubber tube,
Extruded in the extrusion direction of the multilayer pipe by a die, extruded as a tubular rubber from the rubber outlet formed by the tip of the inverted rubber pipe nipple, die, the nipple for the synthetic resin pipe, the tip of the die, the nipple for the inverted rubber pipe, the die Penetrates the center of the rubber pipe and enters the position surrounded by the inner circumference of the rubber pipe extruded from the rubber outlet. The synthetic resin outlet formed by the synthetic resin pipe nipple and the tip of the die is obliquely outward in the extrusion direction. Spreading in a radiant manner, the extruded synthetic resin is pressed against the inner circumference of the rubber tube, and the nipple for the synthetic resin tube has a spout at its tip,
An extruding apparatus for a heterogeneous multi-layer pipe, characterized in that the blowing port sends out a gas having a pressure effective for bringing the synthetic resin pipe and the outer rubber pipe into close contact with each other.