JP6905441B2 - Manufacturing method of laminated tube, composite tube and laminated tube - Google Patents

Description

The present invention relates to a laminated tube, a composite tube, and a method for manufacturing a laminated tube.

Conventional laminated tubes include a fluororesin having excellent resistance to contents and the like, a thermoplastic elastomer having excellent flexibility, and a polyamide resin for obtaining an interlayer adhesive force between the fluororesin and the thermoplastic elastomer. , Are produced by coextruding (see, for example, Patent Document 1).

International Publication No. 2004/110756

However, when the above-mentioned laminated tube is manufactured by actually co-extruding these materials, the laminated tube can maintain its cross-sectional shape in a perfect circular shape immediately after leaving the extrusion molding machine. However, the cross-sectional shape may be crushed. In particular, the inventor of the present application has confirmed that the crushing of the laminated tube as described above is likely to occur when the majority of the laminated tube is occupied by the elastomer in order to ensure flexibility.

An object of the present invention is to provide a laminated tube and a composite tube which are hard to be crushed at the time of manufacturing, and another object of the present invention is a method for manufacturing a laminated tube which can obtain a laminated tube which is hard to be crushed at the time of manufacturing. To provide.

As a result of diligent studies by the inventor of the present application regarding the cause of the cross-sectional shape of the laminated tube being crushed immediately after extrusion as described above, the following new findings have been obtained, and the present invention has been made. Generally, the viscosity of a thermoplastic material or the like decreases as the temperature rises. However, the viscosity characteristics with respect to such a temperature are different for each material, and when a plurality of materials are co-extruded at a predetermined viscosity and extruded, the temperature at which the predetermined viscosity required for extrusion molding may be different for each material. .. In particular, when the material used is a high-viscosity material (for example, a polyamide resin) having a predetermined viscosity at a high temperature, the high-viscosity material must be extruded at a higher temperature than other materials. However, when these materials merge near the extrusion outlet, the heat of the high-viscosity material shifts to a low-viscosity material (for example, a thermoplastic elastomer) that has a predetermined viscosity at a low temperature, and the viscosity of the low-viscosity material further increases. It is unnecessarily lowered, and as a result, the cross-sectional shape immediately after extrusion cannot be maintained in a perfect circular shape and is crushed.

The laminated tube according to the present invention is a laminated tube having at least two layers, an inner layer made of a first material and an outer layer made of a second material, and is arranged adjacent to the inner layer and the outer layer. Further, the first material further has a temperature buffer layer made of a third material, and the first material is a material having the same viscosity as the second material at a temperature different from that of the second material. It is a material having the same viscosity at a temperature intermediate between the temperature of the first material and the temperature of the second material.
According to the laminated tube according to the present invention, the laminated tube is not easily crushed during manufacturing.

In the laminated tube according to the present invention, the first material is preferably a material having the same viscosity at a higher temperature than the second material.
In this case, the laminated tube becomes more practical.

In the laminated tube according to the present invention, the second material is preferably an elastomer.
In this case, the flexibility of the laminated tube can be improved.

In the laminated tube according to the present invention, the first material is preferably a polyamide resin.
In this case, the strength of the laminated tube can be improved, and when another layer is arranged inside the inner layer, the inner layer can function as an adhesive layer.

The laminated tube according to the present invention further has an innermost layer made of a fourth material arranged adjacent to the inside of the inner layer, and the fourth material is preferably a fluororesin.
In this case, the resistance of the laminated tube to the contents and the like can be improved.

In the laminated tube according to the present invention, the first material can be a fluororesin, and the second material can be an elastomer.
In this case, the resistance and flexibility of the laminated tube to the contents and the like can be improved.

In the laminated tube according to the present invention, the third material can be an elastomer.
In this case, when the second material is an elastomer, the adhesiveness with the second material (outer layer) can be improved, and the laminated tube has further excellent flexibility. The elastomer of the third material is an elastomer having different viscosity characteristics from the elastomer of the second material (the temperature at which the viscosity is the same as that of the elastomer of the second material).

In the laminated tube according to the present invention, the third material can be a polyamide resin.
In this case, when the first material is a polyamide resin, the adhesiveness with the second material (inner layer) can be improved, and the laminated tube has further excellent strength. The polyamide resin of the third material is a polyamide resin having a viscosity characteristic different from that of the polyamide resin of the first material (the temperature at which the viscosity is the same as that of the polyamide resin of the first material).

The composite pipe according to the present invention has the laminated tube according to any one of the above, a reinforcing layer covering the laminated tube, and an outer cover covering the reinforcing layer.
According to the composite tube according to the present invention, the laminated tube becomes a composite tube that is not easily crushed during manufacturing.

The method for manufacturing a laminated tube according to the present invention is a method for manufacturing a laminated tube for obtaining any of the above-mentioned laminated tubes, wherein the first material, the second material, and the third material. It has a step of co-extruding at least three materials.
According to the method for manufacturing a laminated tube according to the present invention, a laminated tube that is not easily crushed during manufacturing can be obtained.

According to the present invention, it is possible to provide a laminated tube and a composite tube that are not easily crushed during manufacturing. Moreover, according to this invention, it is possible to provide the manufacturing method of the laminated tube which can obtain the laminated tube which is hard to be crushed at the time of manufacturing.

It is a perspective view which shows the composite tube which concerns on one Embodiment of this invention in a partial cross section which used the laminated tube which concerns on one Embodiment of this invention. It is sectional drawing of the laminated tube shown in FIG. 1A. It is a graph which illustrates the characteristic of viscosity with respect to temperature in each material used for the laminated tube of FIG. 1A and FIG. 1B.

Hereinafter, with reference to the drawings, a laminated tube, a composite tube, and a method for manufacturing the laminated tube according to an embodiment of the present invention will be described.

In FIGS. 1A and 1B, reference numeral 10 is a laminated tube according to an embodiment of the present invention. The laminated tube 10 has at least two layers, an inner layer 1 made of the first material M1 and an outer layer 2 made of the second material M2.

Further, the laminated tube 10 has a temperature buffer layer 3 made of a third material M3. As shown in FIGS. 1A and 1B, the temperature buffer layer 3 is arranged adjacent to the inner layer 1 and the outer layer 2. More specifically, the temperature buffer layer 3 is arranged between the inner layer 1 and the outer layer 2 adjacent to each of the inner layer 1 and the outer layer 2.

Further, in the present embodiment, the laminated tube 10 has an innermost layer 4 made of a fourth material M4. The innermost layer 4 is arranged adjacent to the inside of the inner layer 1. More specifically, the innermost layer 4 is arranged inside the inner layer 1 and adjacent to the inner layer 1.

The laminated tube 10 according to the present embodiment has an innermost layer 4, an inner layer 1, a temperature buffer layer 3, and an outer layer 2 in this order from the inside of the laminated tube 10. That is, the laminated tube 10 is a four-layer laminated tube.

The laminated tube 10 according to the present embodiment is molded by a coextrusion method using an extrusion molding machine (not shown) (hereinafter, also simply referred to as “extrusion molding”). In the present embodiment, the first material M1, the second material M2, the third material M3, and the fourth material M4 each have the characteristics shown in FIG.

FIG. 2 is a graph illustrating the characteristics of the viscosity η with respect to the temperature T (hereinafter, also simply referred to as “viscosity characteristics”) in each of the first material M1 to the fourth material M4. In the graph of FIG. 2, the horizontal axis represents the temperature T (° C), and the vertical axis represents the viscosity η (Pa · s) with respect to the temperature T of each material of the first material M1 to the fourth material M4.

The graph of FIG. 2 is a semi-logarithmic graph in which the viscosity η is shown logarithmically. In the present embodiment, the viscosity η is the viscosity when measured at a shear rate of 270 (mm / s) based on JIS K7199 “Plastic flow characteristic test method using a plastic-capillary rheometer and a slit direometer”.

In FIG. 2, the graph of the white triangular plot shows the viscosity characteristic P4 of the fourth material M4. As represented by the viscosity characteristic P4, the viscosity η (≡η4) of the fourth material M4 decreases as the temperature T (≡T4) of the fourth material M4 increases. That is, the fourth material M4 is a material whose viscosity η4 decreases as the temperature T4 rises.

The fourth material M4 forms the innermost layer 4. In the laminated tube 10 according to the present embodiment, the innermost layer 4 functions as a pipe for circulating the contents (fluid such as liquid or gas). Examples of the fourth material M4 include fluororesins having excellent resistance to contents and the like, such as chemical resistance, gas barrier property, and heat resistance.

Examples of the "fluororesin" include ETFE (tetrafluoroethylene / ethylene copolymer), PVDF (polyvinylidene fluoride (difluoride)), FEP (tetrafluoroethylene / hexafluoropropylene copolymer) and the like. Can be mentioned.

In FIG. 2, the graph of the black circle plot shows the viscosity characteristic P1 of the first material M1. As represented by the viscosity characteristic P1, the viscosity η (≡η1) of the first material M1 decreases as the temperature T (≡T1) of the first material M1 rises. That is, the first material M1 is also a material whose viscosity η1 decreases as the temperature T1 rises.

The first material M1 forms the inner layer 1. The inner layer 1 is arranged adjacent to the innermost layer 4. In the laminated tube 10 according to the present embodiment, the inner layer 1 functions as an adhesive layer that adheres the innermost layer 4 and the temperature buffer layer 3, and thus the innermost layer 4 and the outer layer 2. Examples of the first material M1 include a polyamide resin.

Examples of the "polyamide resin" include nylon such as nylon 6, nylon 12, nylon 11, nylon 66, and nylon 610, and aramid.

On the other hand, in FIG. 2, the graph of the black rhombus plot shows the viscosity characteristic P2 of the second material M2. As represented by the viscosity characteristic P2, the viscosity η (≡η2) of the second material M2 also decreases as the temperature T (≡T2) of the second material M2 rises. That is, the second material M2 is also a material whose viscosity η2 decreases as the temperature T2 rises.

The second material M2 forms the outer layer 2. In the laminated tube 10 according to the present embodiment, the outer layer 2 functions as an elastic layer that imparts flexibility to the laminated tube 10. Examples of the second material M2 include elastomers.

In the present specification, the "elastomer" refers to a material having rubber properties (rubber elasticity) without being crosslinked (vulcanized). In other words, as used herein, the term "elastomer" is an "elastomer" in the industrial sense. Examples of the "elastomer" include thermoplastic elastomers. Examples of the "thermoplastic elastomer" include polyolefin-based thermoplastic elastomer (TPO), polystyrene-based thermoplastic elastomer (TPS), polyamide-based thermoplastic elastomer (TPA), polyurethane-based thermoplastic elastomer (TPU), and polyester-based thermoplastic elastomer. Examples thereof include elastomer (TPC) and vinyl chloride-based thermoplastic elastomer.

When a laminated tube is manufactured by co-extruding these three fourth material M4, the first material M1 and the second material M2, the laminated tube has a cross-sectional shape immediately after leaving the extrusion molding machine. It cannot be held in a perfect circular shape, and the cross-sectional shape may be crushed. Such crushing of the laminated tube is likely to occur when the majority of the laminated tube is occupied by an elastomer, or when the laminated tube has a large diameter. As a specific example of the case where most of the laminated tube is occupied by the elastomer, for example, the wall thickness d4 of the innermost layer 4 is 0.2 mm, the wall thickness d1 of the inner layer 1 is 0.2 mm, and the wall thickness of the outer layer 2 is 0.2 mm. A laminated tube having d2 of 1.0 mm can be mentioned. Further, as a specific example when the laminated tube has a large diameter, for example, the inner diameter of the laminated tube 10 (φ1 in FIG. 1B) is 12 mm or more, and the outer diameter of the laminated tube 10 (φ2 in FIG. 1B) is 15 mm or more. Then, a thin laminated tube having a wall thickness d10 of the laminated tube 10 (d10 = (φ2-φ1) / 2 in FIG. 1B) of 1.5 mm or less can be mentioned.

As a result of diligent studies on the cause of the above-mentioned crushing, the inventor of the present application has obtained the following new findings and has come to the present invention. As shown in the viscosity characteristics P4, P1 and P2 of FIG. 2, in general, the viscosity η of a thermoplastic material or the like decreases as the temperature T increases. However, the viscosity characteristics P4, P1 and P2 with respect to the temperature T are different for each of the fourth material M4, the first material M1 and the second material M2, as shown in FIG. When a plurality of materials of the fourth material M4, the first material M1 and the second material M2 are co-extruded at a predetermined viscosity ηx, as shown in FIG. 2, the fourth material M4, the first material M1 and the second material are used. The temperature of the first material M1 (the first material M1 at the time of coextrusion molding) at which the material M2 has the same viscosity (predetermined viscosity required for extrusion molding) ηx (for example, ηx = 300 as shown in FIG. 2). (T1x), the temperature of the second material M2 (the temperature of the second material M2 at the time of coextrusion) T2x, the temperature of the fourth material M4 (the temperature of the fourth material M4 at the time of coextrusion) T4x may be different. be. In particular, when the material used is a high-viscosity material such as the first material M1, the first material M1 must be extruded at a temperature higher than that of the second material M2 by ΔT = T1x−T2x. However, when the fourth material M4, the first material M1 and the second material M2 merge near the extrusion outlet, the heat of the first material M1 is transferred to the adjacent second material M2, and the viscosity η2 of the second material M2. Is further unnecessarily reduced, and as a result, the cross-sectional shape immediately after extrusion cannot be maintained in a perfect circular shape and is crushed. In particular, in the case of FIG. 2, as is clear from comparing the viscosity characteristic P1 of the first material M1 and the viscosity characteristic P2 of the second material M2, the viscosity η2 of the second material M2 suddenly increases as the temperature T increases. The rate of decrease is larger than the decrease in viscosity η1 of the adjacent first material M1.

Therefore, in the present invention, when the first material M1 is a material having the same viscosity ηx as the second material M2 at a temperature T1x different from the temperature T2x of the second material M2, it is adjacent between the inner layer 1 and the outer layer 2. , A temperature buffer layer 3 made of a third material M3 is arranged. The third material M3 is a material having the same viscosity ηx at a temperature T3x intermediate between the temperature T1x of the first material M1 and the temperature T2x of the second material M2 (the temperature of the third material M3 at the time of coextrusion molding). be. That is, T2x <T3x <T1x, or T1x <T3x <T2x.

In the laminated tube 10 according to the present embodiment, as represented by the viscosity characteristics P1 and P2 in FIG. 2, the first material M1 is a material having the same viscosity ηx at a temperature T1x higher than that of the second material M2. .. That is, T2x <T3x <T1x.

In FIG. 2, the graph of the white round plot shows the viscosity characteristic P3 of the third material M3. As represented by the viscosity characteristic P3, the viscosity η (≡η3) of the third material M3 also decreases as the temperature T (≡T3) of the third material M3 rises. That is, the third material M3 is also a material whose viscosity η3 decreases as the temperature T3 rises.

The third material M3 forms the temperature buffer layer 3. In the laminated tube 10 according to the present embodiment, the temperature buffer layer 3 makes it difficult to transfer the heat from the first material M1 (inner layer 1) to the second material M2 (outer layer 2) when the laminated tube 10 is extruded. It functions as a layer or a layer that prolongs the time required to transfer the heat. Referring to FIG. 2, the third material M3 is a material having the same viscosity ηx at a temperature T3 (T3 = T3x) intermediate between the temperature T1 of the first material M1 and the temperature T2 of the second material M2. be. That is, in FIG. 2, the third material M3 has the viscosity at an intermediate temperature T3x between the temperature T1x of the first material M1 having the same viscosity ηx and the temperature T2x of the second material M2 having the same viscosity ηx. It is a material that becomes ηx.

According to the laminated tube 10 according to the present embodiment, when the laminated tube 10 is extruded with the same viscosity ηx, the third material M3 (temperature buffering layer 3) becomes the first material M1 (inner layer 1) and the second material M1 (inner layer 1). By interposing with the material M2 (outer layer 2), the temperature T1x from the first material M1 is not directly transmitted to the second material M2 (outer layer 2). In addition, the third material M3 (temperature buffer layer 3) is a material having the same viscosity ηx at a temperature T3x intermediate between the temperature T1x of the first material M1 and the temperature T2x of the second material M2. It is harder to soften than the second material M2 (outer layer 2). Therefore, the cross-sectional shape of the laminated tube 10 can be maintained in a perfect circular shape even after co-extrusion from the extrusion molding machine and until it is put into cooling water, for example.

In the laminated tube 10 according to the present embodiment, T2x <T3x <T1x. When T3x <T2x, the third material M3 is unnecessarily softened and the object cannot be achieved. When T1x <T3x, the temperature T3x at which the third material M3 has the same viscosity ηx becomes too high, and the object cannot be achieved either. Further, in the laminated tube according to the present invention, T1x <T3x <T2x can be set. This is the same reason as above.

Further, in the laminated tube 10 according to the present embodiment, the third material M3 is arranged at a position adjacent to the first material M1 or the second material M2. When the third material M3 is not adjacent to the first material M1 or the second material M2, that is, between the first material M1 and the third material M3, or between the third material M3 and the second material M2. In addition, when another layer made of another material is interposed, there is a possibility that the purpose cannot be achieved depending on the other material.

Therefore, according to the laminated tube 10 according to the present embodiment, the laminated tube is not easily crushed during manufacturing.

In particular, in the laminated tube 10 according to the present embodiment, the first material M1 is a material having the same viscosity ηx at a temperature T1x higher than that of the second material M2. In this case, the inner layer 1 is less likely to be softened than the outer layer 2 even if the temperature T rises, so that the inner layer 1 becomes a more practical laminated tube.

In particular, in the laminated tube 10 according to the present embodiment, the second material M2 is an elastomer. In this case, the flexibility of the laminated tube 10 can be improved. Therefore, according to the laminated tube 10 according to the present embodiment, the laminated tube has flexibility and is not easily crushed during manufacturing. In other words, according to the laminated tube 10 according to the present embodiment, the laminated tube has both flexibility and moldability.

Further, in the laminated tube 10 according to the present embodiment, the first material M1 is a polyamide resin. In this case, the strength of the laminated tube (for example, the strength against tension, compression, bending, impact, etc.) can be improved. In particular, in the laminated tube 10 according to the present embodiment, the first material M1 can function as an adhesive layer for adhering the innermost layer 4 and the temperature buffer layer 3, and thus the innermost layer 4 and the outer layer 2. Therefore, according to the laminated tube 10 according to the present embodiment, the innermost layer 4 and the outer layer 2 are bonded to each other by adhesion.

Further, the laminated tube 10 according to the present embodiment further has an innermost layer 4 made of a fourth material M4 arranged adjacent to the inside of the inner layer 1, and the fourth material M4 is a fluororesin. In this case, the resistance of the laminated tube 10 to the contents and the like can be improved.

By the way, in the laminated tube 10 according to the present embodiment, the third material M3 can be an elastomer. If the third material M3 is an elastomer, the ratio of the elastomer to the laminated tube 10 can be increased. In this case, the laminated tube has more excellent flexibility. Further, if the third material M3 is an elastomer, the outer layer 2 and the temperature buffer layer 3 are made of the same material, so that the outer layer 2 can be easily adhered to the temperature buffer layer 3. Therefore, when the outer layer 2 is made of an elastomer as in the laminated tube 10 according to the present embodiment, the adhesiveness with the outer layer 2 can be improved. The elastomer of the third material M3 is an elastomer having different viscosity characteristics from the elastomer of the second material M2 (the temperature at which the viscosity is the same as that of the elastomer of the second material M2 is higher). Further, as the "elastomer" of the third material M3, for example, an elastomer harder than the elastomer of the outer layer 2 (elastomer having a viscosity η3 higher than the viscosity η2 of the elastomer of the outer layer 2) and the like can be mentioned.

Alternatively, in the laminated tube 10 according to the present embodiment, the third material M3 can be a polyamide resin. If the third material M3 is a polyamide resin, the ratio of the polyamide resin to the laminated tube 10 can be increased. In this case, the laminated tube has even higher strength. Further, if the third material M3 is a polyamide resin, the inner layer 1 and the temperature buffer layer 3 are made of the same material, so that the inner layer 1 can be easily adhered to the temperature buffer layer 3. Therefore, when the inner layer 1 is made of a polyamide resin as in the laminated tube 10 according to the present embodiment, the adhesiveness with the innermost layer 4 can be improved. The polyamide resin of the third material M3 is a polyamide resin having different viscosity characteristics from the polyamide resin of the second material M2 (the temperature ηx is higher than that of the polyamide resin of the second material M2). .. Examples of the "polyamide resin" of the third material M3 include polyamides softer than the polyamide of the inner layer 1 (polyamide resin having a viscosity η3 higher than the viscosity η1 of the polyamide resin of the inner layer 1).

By the way, in the laminated tube 10 according to the present embodiment, the third material M3 has the viscosity characteristic P3 of FIG. When the third material M3 is a material having the viscosity characteristic P3 of FIG. 2, the same viscosity (predetermined viscosity required for extrusion molding) ηx is at least 100 (Pa · s) ≦ ηx ≦ 300 (Pa · s). Within the range satisfying (see FIG. 2), the third material M3 has the same viscosity ηx at a temperature T3x intermediate between the temperature T1x of the first material M1 and the temperature T2x of the second material M2. Therefore, in the case of the present embodiment, if the laminated tube 10 is extruded within the above range (100 (Pa · s) ≦ ηx ≦ 300 (Pa · s)), the laminated tube 10 is crushed at the time of manufacture. It becomes a difficult laminated tube.

On the other hand, as a range of the predetermined viscosity ηx required for extrusion molding, for example, a range of 100 (Pa · s) ≦ ηx ≦ 600 (Pa · s) can be mentioned. In the laminated tube 10 according to the present embodiment, the same viscosity ηx is the viscosity η within the range (100 (Pa · s) ≦ η ≦ 600 (Pa · s)).

According to the present invention, the third material M3 is a material having the same viscosity ηx at a temperature T3 intermediate between the temperature T1 of the first material M1 and the temperature T2 of the second material M2. The third material M3 shown is exemplary. Therefore, according to the present invention, when extrusion molding is performed with a viscosity ηx other than the above range (100 (Pa · s) ≦ ηx ≦ 300 (Pa · s)) according to the present embodiment, the temperature of the first material M1 By selecting a material having the viscosity ηx at a temperature T3 intermediate between T1x and the temperature T2x of the second material M2 as the new third material M3, a laminated tube that is not easily crushed during manufacturing can be obtained. Further, in the viscosity characteristics P1 to P4 of FIG. 2, the portion where the viscosity characteristic is not disclosed can be easily measured.

That is, according to the laminated tube according to the present invention, the third material M3 of the temperature buffer layer 3 is not limited to the material represented by the viscosity characteristic P3 shown in FIG. The third material M3 is a material that can be appropriately selected depending on the relationship with the viscosity characteristics of each material as illustrated in FIG. As long as T2x <T3x <T1x or T1x <T3x <T2x is satisfied, the first material M1, the second material M2, and the third material M3 can be appropriately selected.

Next, the laminated tube according to another embodiment of the present invention will be described. According to the present invention, as the laminated tube according to another embodiment of the present invention, for example, the first material M1 can be a fluororesin and the second material M2 can be an elastomer. In the following description, the parts substantially the same as those in FIGS. 1A, 1B, and 2 have the same reference numerals, and the description thereof will be omitted.

The laminated tube according to the other embodiment is arranged adjacent to the inner layer 1 made of the first material M1 (fluororesin), the outer layer 2 made of the second material M2 (elastomer), and the inner layer 1 and the outer layer 2. It has three layers with the temperature buffer layer 3 made of the third material M3. That is, in the laminated tube according to the other embodiment, in the laminated tube 10 of FIGS. 1A and 1B, the inner layer 1 made of polyamide resin, which is arranged adjacent to the innermost layer 4 and the temperature buffering layer 3, is omitted. This is a three-layer laminated tube.

In the laminated tube according to the present embodiment, the inner layer 1 is made of the first material M1 similar to the fourth material M4 in the above-described embodiment. The second material M2 and the third material M3 in the present embodiment are the same materials as the second material M2 and the third material M3 in the above-described embodiment, respectively. Referring to FIG. 2, the third material M3 has a temperature T3 (FIG. 2) intermediate between the temperature T4 of the fourth material M4 (in this embodiment, the temperature T1 of the first material) and the temperature T2 of the second material M2. Then, T3 = T3x), and the materials have the same viscosity ηx. In other words, also in this embodiment, the third material M3 is the same as the temperature T1x of the first material M1 having the same viscosity ηx (the temperature T4x of the fourth material M4 in the above-described embodiment shown in FIG. 2). It is a material having a viscosity ηx at a temperature T3x intermediate with the temperature T2x of the second material M2 having a viscosity ηx. In this case, the resistance and flexibility of the laminated tube to the contents and the like can be improved.

Next, a method for manufacturing a laminated tube according to an embodiment of the present invention will be described. The method for manufacturing a laminated tube according to the present embodiment is a manufacturing method for obtaining the above-mentioned laminated tube 10. In the following description, the parts substantially the same as those described above have the same reference numerals, and the description thereof will be omitted.

The method for manufacturing a laminated tube according to the present embodiment is a third method in which an inner layer 1 made of a first material M1, an outer layer 2 made of a second material M2, and an inner layer 1 and an outer layer 2 are arranged adjacent to each other. This is a method for manufacturing a laminated tube 10 having four layers, that is, a temperature buffer layer 3 made of a material M3 and an innermost layer 4 made of a fourth material M4 arranged adjacent to the inside of the inner layer 1.

The method for producing a laminated tube according to the present invention includes a step of co-extruding at least three materials of a first material M1, a second material M2, and a third material M3. The present embodiment has a step of co-extruding the first material M1 to the fourth material M4. In the step, these four first material M1 to fourth material M4 are co-extruded from the extrusion molding machine. As the extrusion molding machine, for example, the extrusion temperature of each of the first material M1 to the fourth material M4 (the temperature T1x to T4x of each material M1 to M4 at the time of coextrusion molding) is the temperature T2x (= 210) of the second material M2. (° C)) The above extrusion molding machine can be used. More specific extrusion temperatures include, for example, temperatures in the range of 250 ° C to 280 ° C. The four materials of the first material M1 to the fourth material M4 merge near the extrusion outlet, and the third material M3 is arranged adjacent to the first material M1 and the second material M2, and the fourth material M3 is arranged adjacent to each other. The material M4 is arranged adjacent to the inside of the first material M1. As a result, the laminated tube 10 having four layers, the innermost layer 4, the inner layer 1, the temperature buffer layer 3, and the outer layer 2, is extruded from the extrusion molding machine in this order from the inside. It should be noted that the viscosities η (= ηx) when extruding each of the first material M1 to the fourth material M4 (before merging) do not necessarily have to be the same. For example, if the viscosities η when the materials of the first material M1 to the fourth material M4 merge have the same viscosity ηx, the extrusion molding machine allows the viscosity η at the time of extrusion (before merging). They can be different from each other within the range of viscosity η.

In the method for manufacturing a laminated tube according to the present embodiment, for the first material M1 to the fourth material M4, for example, a material satisfying the viscosity characteristics P1 to P4 shown in FIG. 2 is used.

In the above step, as described above, the first material M1 has a temperature different from the temperature of the second material M2 (the temperature of the second material M2 at the time of coextrusion) T2x (the temperature of the first material M1 at the time of coextrusion). It is a material having the same viscosity ηx as the second material M2 at T1x. In the method for manufacturing a laminated tube according to the present embodiment, the first material M1 is a material having the same viscosity ηx at a temperature T1x higher than that of the second material M2. Further, as described above, the third material M3 also has the temperature T1 of the first material M1 (the temperature of the first material M1 at the time of coextrusion molding) and the temperature of the second material M2 (the temperature of the second material M1 at the time of coextrusion molding). (Temperature) The material has the same viscosity ηx at T3, which is an intermediate temperature with T2 (the temperature of the third material M3 at the time of coextrusion molding).

According to the method for manufacturing a laminated tube according to the present embodiment, the third material M3 is arranged adjacent to the first material M1 and the second material M2, so that the third material M3 is placed between the inner layer 1 and the outer layer 2. The temperature buffer layer 3 is arranged adjacent to each other. Therefore, according to the method for manufacturing a laminated tube according to the present embodiment, it is possible to obtain a laminated tube 10 that is not easily crushed during manufacturing. When obtaining a three-layer laminated tube according to another embodiment of the present invention, in the above step, the first material M1 made of fluororesin, the second material M2 made of elastomer, and the elastomer or polyamide resin are used. The third material M3 is co-extruded.

In particular, in the method for manufacturing a laminated tube according to the present embodiment, the first material M1 is a material that achieves the same viscosity ηx at a temperature T1x higher than that of the second material M2. In this case, a more practical laminated tube 10 can be obtained.

Next, the composite pipe according to the embodiment of the present invention will be described. In FIG. 1, reference numeral 100 is a composite tube according to an embodiment of the present invention. The composite pipe 100 according to the present embodiment has a laminated tube 10, a reinforcing layer 5 that covers the laminated tube 10, and an outer cover 6 that covers the reinforcing layer 5. According to the composite tube 100 according to the present embodiment, the laminated tube 10 becomes a composite tube that is not easily crushed during manufacturing.

Examples of the reinforcing layer 5 include a reinforcing layer made of polyester fibers such as polyethylene terephthalate (PET) fiber. Further, examples of the jacket 6 include the above-mentioned elastomer, rubber (in the present specification, one having rubber properties by cross-linking (vulcanization)) and the like.

As described above, the laminated tube is crushed when, for example, the inner diameter φ1 of the laminated tube 10 is 12 mm or more, the outer diameter φ2 of the laminated tube 10 is 15 mm or more, and the wall thickness of the laminated tube 10 is thin (laminated). The wall thickness d10 of the tube 10 is 1.5 mm or less). That is, it tends to occur when the inner diameter φ1 and the outer diameter φ2 of the laminated tube 10 are large and the wall thickness d10 of the laminated tube 10 is thin. Therefore, in the laminated tube 10 according to the present embodiment, when the outer diameter φ2 of the laminated tube 10 is 15 mm or more, the inner diameter φ1 of the laminated tube 10 is 13 mm or more, and the wall thickness d10 of the laminated tube 10 is thin (thickness). It is effective that d10 is set to 1.5 mm or less).

Further, as shown in FIG. 1B, in the laminated tube 10, the wall thickness d1 of the inner layer 1, the wall thickness d2 of the outer layer 2, the wall thickness d3 of the temperature buffer layer 3 and the wall thickness d4 of the innermost layer 4 are the wall thickness d4 of the laminated tube 10. It can be set as appropriate according to the application. For example, the wall thickness d1 = 0.25 mm, the wall thickness d2 = 1 mm, the wall thickness d3 = 0.25 mm, and the wall thickness d4 = 0.25 mm.

1: Inner layer, M1: First material, P1: Viscosity characteristics of the first material, T1: Temperature of the first material, T1x: Temperature of the first material having the same viscosity, 2: Outer layer, M2: Second material, P2: Viscosity characteristics of the second material, T2: Temperature of the second material, T2x: Temperature of the second material having the same viscosity, 3: Temperature buffer layer, M3: Third material, P3: Viscosity characteristics of the third material , T3: Temperature of the third material, T3x: Temperature of the third material having the same viscosity, 4: Inner layer, P4: Viscosity characteristics of the fourth material, M4: Fourth material, T4: Temperature of the fourth material, T4x: Temperature of the fourth material having the same viscosity, 5: Reinforcing layer, 6: Cover, 10: Laminated tube, 100: Composite tube, η: Viscosity, ηx: Same viscosity, T: Temperature

Claims (8)

An inner layer made of a first material, and an outer layer made of a second material, said inner layer and disposed between and adjacent to the outer layer, has a temperature buffer layer made of a third material, wherein the first The material is a material having the same viscosity as the second material at a temperature different from that of the second material, and the third material is a temperature intermediate between the temperature of the first material and the temperature of the second material. A method for manufacturing a laminated tube for obtaining a laminated tube, which is a material having the same viscosity.
A method for producing a laminated tube, which comprises a step of co-extruding at least three materials of the first material, the second material, and the third material . The method for manufacturing a laminated tube according to claim 1, wherein the first material is a material having the same viscosity at a temperature higher than that of the second material. The method for producing a laminated tube according to claim 2, wherein the second material is an elastomer. The method for producing a laminated tube according to claim 2 or 3, wherein the first material is a polyamide resin. The laminated tube further has an innermost layer made of a fourth material arranged adjacent to the inside of the inner layer.
The method for manufacturing a laminated tube according to claim 3 or 4, wherein the fourth material is a fluororesin. The method for producing a laminated tube according to claim 2, wherein the first material is a fluororesin and the second material is an elastomer. The method for producing a laminated tube according to any one of claims 3 to 6, wherein the third material is an elastomer. The method for manufacturing a laminated tube according to any one of claims 3 to 6, wherein the third material is a polyamide resin.

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