JP2009068549A - Large-diameter rubber hose - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a large-diameter rubber hose which can retain adhesive strength between a rubber layer and a reinforcement layer even after long-time vulcanization of 500 to 1000 minutes, which can prevent the peeling of the rubber layer from the reinforcement layer while being used, which has a small change in the diameter of the hose caused by the pressure of a fluid even at the time of transportation of the fluid, and which is excellent in durability and dimensional stability. <P>SOLUTION: The large-diameter rubber hose is formed by using vulcanized rubber which is reinforced by combining fiber fabrics and/or fiber cords which is constituted by composite fiber of aramid fiber and nylon fiber. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a large-diameter rubber hose reinforced by combining a fiber fabric and / or a fiber cord.

  Conventionally, when a large amount of liquid is transported using a hose, for example, when a tanker moored offshore and a land facility are directly connected by a hose to perform cargo handling work such as crude oil, the liquid is transported efficiently. Therefore, a large-diameter hose having an inner diameter of about 300 to 1000 mm is used depending on the transport scale. Since such a large-diameter hose is generally subjected to high pressure when transporting liquid such as crude oil, it has an inner rubber layer on the inner peripheral side and an outer rubber layer on the outer peripheral side, and the inner rubber layer and the outer rubber layer It has a structure in which a reinforcing material layer made of synthetic fiber or wire or the like is laminated between them, and the wall thickness including the inner and outer rubber layers and the reinforcing material layer is very thick at 50 to 100 mm.

  In a normal production, the large-diameter rubber hose is formed by forming the laminated structure including unvulcanized inner and outer rubber layers and a reinforcing material layer, and then combining the inner and outer rubber layers and the reinforcing material layer. It is often produced by vulcanization adhesion. In this case, as described above, the thickness of the hose including the rubber layer and the reinforcing material layer is very thick as 50 to 100 mm, so that the inside is completely vulcanized and cured for 500 to 1000 minutes. Heat vulcanization is performed for a long time.

  On the other hand, as a reinforcing material used for a rubber hose reinforcing material layer, a fiber obtained by twisting a plurality of polyethylene terephthalate (PET) fibers because of its high strength, high elastic modulus, low elongation and excellent dimensional stability. In many cases, a cord or a fiber fabric made of the fiber cord is used. However, this PET fiber does not necessarily have sufficient heat resistance, and when used in the large-diameter hose, it causes thermal deterioration while vulcanizing and curing the rubber over a long time of 500 to 1000 minutes. The problem that the adhesiveness between the layer and the reinforcing material layer is remarkably lowered has become apparent. If the adhesion between the rubber layer and the reinforcing material layer decreases after vulcanization, the rubber layer and the reinforcing material layer peel off due to bending motion or vibration applied to the hose in use, and the hose is damaged early. May be incurred. In addition, due to the heat resistance problem of the PET fiber, it has been difficult to increase the vulcanization temperature to shorten the vulcanization time and improve the productivity.

  In addition, examples of other reinforcing materials include aramid fibers and nylon fibers represented by Kevlar fibers from the viewpoint of strength, heat resistance, etc., but when aramid fibers are used as reinforcing materials for the above large-diameter hoses. Since the elongation of the fiber is small and the fatigue durability is not sufficient, the hose becomes weak against buckling. When nylon fiber is used, the elongation is too large, so that the fluid was passed through the hose. There is a concern that the change in the hose diameter at the time becomes large.

  On the other hand, in Japanese Patent Application Laid-Open No. 2004-108555 (Patent Document 1), the applicant uses a composite fiber woven fabric in which a nylon fiber is combined with a PET fiber as a reinforcing material layer, thereby reducing heat resistance and the like that are insufficient for the PET fiber. We proposed a rubber hose that was supplemented with nylon fibers, maintained the reinforcing effect of PET fibers, prevented thermal deterioration due to long-term vulcanization, and significantly reduced the decrease in adhesive strength between the reinforcing material and rubber. However, due to the composite of nylon fibers, the modulus of the entire composite fiber is reduced, and the problem that the hose diameter is greatly enlarged due to the pressure when the fluid is passed through the hose has become apparent. In use, when the hose diameter is greatly enlarged, the transport pressure of the fluid may be reduced and transport efficiency may be reduced.

  Therefore, the adhesive force between the rubber layer and the reinforcing material layer is maintained even after vulcanization for a long time, and the rubber layer and the reinforcing material layer do not peel off during use, and the hose by the fluid pressure is also used during fluid transportation. It is desired to develop a large-diameter rubber hose with a small diameter change and excellent durability and dimensional stability.

JP 2004-108555 A

  The present invention was made in view of the above circumstances, the adhesive force between the rubber layer and the reinforcing material layer is maintained even after vulcanization for a long time, and the rubber layer and the reinforcing material layer do not peel off during use. Another object of the present invention is to provide a large-diameter rubber hose that is small in change in hose diameter due to fluid pressure and excellent in durability and dimensional stability during fluid transportation.

  As a result of intensive studies to solve the above problems, the present inventor can compensate the fatigue durability of the aramid fiber by combining the aramid fiber and the nylon fiber, and these fibers can be used as a reinforcing material. By using a fiber woven fabric and / or fiber cord using a composite fiber containing, the reinforcing material does not undergo thermal degradation even after vulcanization for a long time of 500 to 1000 minutes, and the adhesive strength to the rubber layer is increased. Furthermore, since the composite fiber has low elongation and high strength, when a fluid is passed through a hose manufactured using the composite fiber as a reinforcing material, the change in hose diameter due to the pressure of the fluid is small. And the present invention has been reached.

  That is, the present invention relates to a large-diameter rubber hose formed using a vulcanized rubber reinforced by combining a fiber woven fabric and / or a fiber cord, and the fiber woven fabric and / or fiber cord includes an aramid fiber and a nylon fiber. A large-diameter rubber hose comprising a composite fiber of

Since the large-diameter rubber hose of the present invention maintains a sufficient adhesive force between the rubber layer and the reinforcing material layer after prolonged vulcanization and curing, the rubber layer and the reinforcing material layer are peeled off during use. Further, when the fluid is passed through the hose, the change in the hose caliber due to the pressure of the fluid is small, so that the decrease and fluctuation of the transport pressure accompanying the caliber expansion can be suppressed.
Moreover, since the conjugate fiber used in the present invention has high heat resistance, it is possible to shorten the vulcanization time and improve the production efficiency by setting the vulcanization temperature high.

The large diameter rubber hose of the present invention will be described in detail.
The large-diameter rubber hose of the present invention has an inner rubber layer on the inner peripheral side of the hose and an outer rubber layer on the outer peripheral side, and a reinforcing material comprising a fiber fabric and / or fiber cord between the inner rubber layer and the outer rubber layer. It has a laminated structure with layers interposed.

  As the reinforcing material layer, a composite fiber made of aramid fiber and nylon fiber (hereinafter sometimes referred to as aramid / nylon composite fiber) cord and / or a composite fiber fabric obtained by weaving the composite fiber are used. .

  The aramid fiber is a kind of polyamide fiber similar to the nylon fiber, and is a polyamide fiber in which all molecular skeletons are aromatic. The aramid fibers are roughly classified into two types: para-aramid fibers in which the benzene nuclei that form the skeleton are linearly arranged, and meta-aramid fibers in a zigzag manner. Because para-aramid fibers have a rigid molecular structure, they exhibit excellent properties in mechanical properties such as high strength, high elasticity, and low expansion / contraction, and meta-aramid fibers have excellent heat resistance and flame resistance. . In the present invention, a conventionally known aramid fiber can be used in the present invention, and is not particularly limited. However, a para-aramid fiber that is more excellent in mechanical properties such as strength and elastic modulus is preferably used. Can do.

  Examples of the para-aramid fiber include polyparaphenylene terephthalamide (PPTA), which is a polycondensate of terephthalic acid dichloride and paraphenylenediamine, which is made into a fiber by a dry spinning method, and terephthalic acid dichloride and paraphenylenediamine. Examples of the three components include 3,4-diaminodiphenyl ether (3,4-DDA) added, copolymerized, and fiberized by a wet spinning method. One type alone or two or more types can be appropriately selected and used. Good. Moreover, these can use a commercial item and can mention "Kevlar" by Du Pont, "Technola" by Teijin Ltd., "Twaron" by Akzo, etc. In the present invention, Kevlar fibers can be suitably used.

  As the nylon fiber, conventionally known fibers can be used, and are not particularly limited, and specific examples include 6,6-nylon, 6-nylon, 4,6-nylon, MXD6 nylon and the like. It can be used individually by 1 type or in combination of 2 or more types. In the present invention, 6,6-nylon can be preferably used.

  In the present invention, the aramid fiber and the nylon fiber are combined to form an aramid / nylon composite fiber cord and a composite fiber fabric. The composite fiber cord is obtained by twisting together a predetermined number of aramid fibers and nylon fibers, each of which is individually twisted, and the composite fiber fabric is usually formed using the composite fiber cord. It is obtained by making it into a woven fabric according to the law.

  The total fineness D (decitex: dtex) of the aramid fiber and the nylon fiber constituting the aramid / nylon composite fiber cord is determined by the required strength of the composite fiber cord, but is usually 2000 to 11000 dt, particularly 3000 to 5500 dt. It is preferable that If it is less than 2000 dt, the strength of the composite fiber cord may be reduced and sufficient pressure resistance may not be obtained. If it exceeds 11000 dt, the assembly efficiency will be reduced, making it difficult to obtain sufficient cord strength for the thickness. Economically unfavorable. Furthermore, the woven fabric becomes thick, and there is a possibility that the workability of laminating the reinforcing material layer is lowered.

  Further, the ratio of the fineness of the aramid fiber to the fineness of the entire aramid / nylon composite fiber cord (fineness of the aramid fiber / total fineness of the entire composite fiber × 100 (%)) is usually 35 to 80%, particularly 44 to 71%. It is preferable that When the fineness ratio is less than 35%, the strength and creep may be increased, and when it exceeds 80%, the bending fatigue resistance of the hose may be decreased.

  The upper twist coefficient of the aramid / nylon composite fiber cord is usually 1440 to 2400, particularly preferably 1600 to 1950. If the upper twist coefficient is less than 1440, the bending fatigue resistance may be lowered, and if it exceeds 2400, sufficient strength may not be obtained, and the elongation and creep may be increased.

The above-mentioned upper twist coefficient is a numerical value calculated by the following equation from the total fineness D (dt) of the fibers constituting the fiber cord and the upper twist number G (times / 10 cm). The larger the fiber cord, the greater the elongation of the fiber cord as a whole.

  Further, the number of lower twists is usually the same as the number of upper twists, but it is not always necessary to be the same, and can be appropriately determined according to the required characteristics of the composite fiber. For example, the elongation of the entire composite fiber can be increased by reducing the number of lower twists of the nylon fiber relative to the number of upper twists. In the present invention, the number of lower twists is preferably in the range of 0.5 to 1 times the number of upper twists.

  The aramid / nylon composite fiber fabric can be produced by weaving the fiber cord of the aramid / nylon composite fiber according to a conventional method. At this time, the composite fiber fabric may be composed of only the above-mentioned aramid / nylon composite fiber cord, and the above-mentioned composite fiber cord is a main constituent cord and includes an aramid fiber cord and / or a nylon fiber cord. Also good.

  The weaving method of the composite fiber fabric is not particularly limited, and a known weaving method such as plain weaving, straight warp weaving, twill weaving, and weaving weaving may be employed. Moreover, there is no restriction | limiting in particular also in the number of cords which comprise a composite fiber fabric, etc., It determines suitably according to the required characteristic of the large diameter rubber hose obtained.

  In a normal case, the composite fiber fabric is a weave weave in which aramid / nylon composite fiber cords as warp yarns are arranged in parallel at a predetermined angle with respect to the length direction of the large-diameter rubber hose and bundled with weft yarns. Generally, cotton yarn, rayon, PET, PET / cotton blended yarn or the like is used. The number of aramid / nylon composite fiber cords as warp yarns is appropriately determined according to the fineness and required characteristics of the large-diameter rubber hose to be obtained, but is usually 30 to 70 / 5cm.

  The aramid / nylon composite fiber cord may be an aramid / nylon core-sheath fiber cord in which a nylon coating layer is formed on the outer periphery of an aramid fiber according to a conventional method, and may be appropriately selected according to the required characteristics of a large-diameter rubber hose. .

  On the other hand, the rubber composition constituting the rubber body of the large-diameter rubber hose of the present invention is not particularly limited as long as it is usually used in this field. Specifically, natural rubber (NR), Styrene butadiene rubber (SBR), nitrile rubber (NBR), chloroprene rubber (CR), chlorosulfonated polyethylene (CSM), urethane rubber (U), acrylic rubber (ACN, ANM), ethylene propylene rubber (EPM, EPDM), Ethylene acrylic rubber (AEM), butyl rubber (IIR), butadiene rubber (BR) and the like can be used singly or in combination of two or more. In the present invention, NR, SBR, BR and the like can be suitably used. The rubber composition used in the inner rubber layer and outer rubber layer can be appropriately selected according to the type and temperature of the fluid to be transported, the use environment of the hose, required characteristics, and the like.

  Further, vulcanizing agents, vulcanization accelerators, anti-aging agents, carbon, zinc white (ZnO), waxes ordinarily used in the rubber industry within the range not impairing the object of the present invention. In addition, additives such as antioxidants, fillers, foaming agents, plasticizers, lubricants, tackifiers, petroleum resins, ultraviolet absorbers, and dispersants can be appropriately blended.

  In the large-diameter rubber hose of the present invention, a normal production method for this type of rubber hose can be applied. For example, an inner rubber layer made of an unvulcanized rubber composition appropriately blended with the above rubber components and additives, and Between the outer rubber layers, the necessary number of fiber woven fabrics and / or fiber cords composed of aramid fibers and nylon fibers coated with adhesive rubber are laminated and arranged as a reinforcing material layer, and vulcanized according to conventional methods. By doing so, it can be easily manufactured. At this time, NR, SBR, BR or the like can be suitably used as the adhesive rubber covering both surfaces of the reinforcing material. Further, the vulcanization conditions are not particularly limited since the thermal deterioration of the reinforcing material does not substantially occur, and can be selected from a wide range of conditions such as 120 to 160 ° C. and 300 to 1000 minutes. In particular, even when vulcanized for a long time of 500 to 1000 minutes, there is no problem of thermal deterioration of the reinforcing fiber and a decrease in adhesion due to the thermal deterioration, it has good bending fatigue resistance, and dimensional stability. A large-diameter rubber hose that excels in quality can be manufactured easily and reliably.

Before the composite fiber fabric and / or the composite fiber cord is coated on both sides with the adhesive rubber as described above, the method is not particularly limited, but in the present invention, the composite fiber fabric and / or the composite fiber cord is used. It is possible to employ a method of dipping in an adhesive, drying, and heat treatment. For example, as an adhesion / heat treatment process, after immersion-drying-heat treatment in an ordinary manner with an aqueous solution of an epoxy compound (Denacol EX313, EX314, EX421 manufactured by Nagase Sangyo Co., Ltd.) in the first bath, the RFL solution ( Similarly, a method of adhering an adhesive by immersing, drying and heat-treating with a resorcin / formalin / latex solution) can be preferably used. Thereby, the adhesive force between the composite fiber fabric (cord) and the adhesive rubber layer when the composite fiber fabric and / or the composite fiber cord is disposed between the unvulcanized rubber layers and vulcanized can be improved. .
In addition, the solid content adhesion amount in that case is 5-12 mass% normally with respect to a composite fiber fabric and / or a composite fiber cord.

  EXAMPLES Hereinafter, although an Example and a comparative example are given and this invention is demonstrated in detail, this invention is not restrict | limited to the following Example.

[Examples 1-9, Comparative Examples 1-6]
Reinforcing the weave of the number of placements shown in Table 1 using the fiber cords shown in Table 1 (polynosic 300 dt / 1 (one twist, 300 dt as weft), and number of placements of 4/5 cm) The evaluation body was produced with the following method using the fiber fabric, and the characteristic was evaluated. The evaluation results are shown in Table 2.

-Adhesive heat treatment anti-adhesive heat treated adhesive fabric (epoxy compound aqueous solution and RFL solution) is dipped in an adhesive solution (drying and heat treatment), dried and heat-treated to produce an adhesive heat treatment anti-adhesive solution, and the following (1 ) To (4).
(1) Strength (N / piece) and elongation (%)
In accordance with JIS L1017, one fiber cord was tested under the conditions of a grip interval of 25 cm and a tensile speed of 30 cm / min, and the strength and elongation at the time of cutting were measured.
(2) Dry heat shrinkage (%)
In accordance with JIS L1017 (Method B), a fiber cord whose yarn length was accurately measured was left in a dryer at a set temperature of 180 ° C. for 30 minutes, then removed from the dryer and left for 30 minutes to measure the yarn length. The dry heat shrinkage was calculated.
(3) Strength (g / d)
The strength value measured in the item (1) was converted from N units to g units and calculated by dividing by the total denier number of the fiber cord (0.9 d (denier) = 1.0 dt (decitex)).
(4) Creep (%)
In accordance with JIS L1017, after accurately measuring the yarn length of the fiber cord, a load of 0.88 cN / dt (for example, 1670 × 2 × 0.88 / 100 in the case of a structure in which two yarns of 1670 dt are twisted together) 29.4 N), the yarn length after standing at room temperature for 30 minutes was measured, and the creep rate was calculated.

-Properties after vulcanization As properties after vulcanization of the present invention, the strength retention after bending, the strength retention and adhesiveness were evaluated by the following methods (1) to (3).
(1) Strength retention after bending (%)
Between the two NR / SBR-based unvulcanized rubber sheets (thickness: 4.5 mm), three sheets of the above-mentioned adhesive heat treatment coated on both sides with a 0.6 mm-thick NR / SBR-based unvulcanized rubber were laminated. , 1.5 MPa and 145 ° C. for 30 minutes by heating and pressurizing for vulcanization adhesion and integration.
The evaluation body was put on a pulley and subjected to a bending test under the following conditions. Then, the reinforcing fiber woven fabric of the innermost layer at the time of bending was taken out, and the strength was measured in the same manner as the strength measurement method for the adhesive heat treatment, and the retention rate ( The strength after bending ÷ strength before bending × 100) was calculated.
Pulley diameter: 100mm
Load: 5% of strength at break
Number of flexing: 200,000 times (2) Strength retention (%)
Between the two NR / SBR-based unvulcanized rubber sheets (thickness: 4.5 mm), three sheets of the above-mentioned adhesive heat treatment coated on both sides with a 0.6 mm-thick NR / SBR-based unvulcanized rubber were laminated. , 1.5 MPa and 145 ° C. under the condition of heating and pressurizing for 1440 minutes to obtain a vulcanized and integrated product.
The reinforcing fiber woven fabric was taken out from the evaluated body, and the strength was measured in the same manner as the above-described method for measuring the strength of the adhesive heat treatment, and was calculated as the ratio of the strength after vulcanization to the strength of the adhesive heat treatment before vulcanization.
(3) Adhesiveness (peeling test)
Between two strips of NR / SBR unvulcanized rubber sheet (thickness 2 mm, width 25 mm ± 0.5 mm, length 100 mm), NR / SBR unvulcanized rubber with a thickness of 0.6 mm Two sheets of the above-mentioned adhesive heat treatment coated on both sides are laminated and vulcanized and bonded by heating and pressing at 145 ° C. for 30 minutes or 1440 minutes as an evaluation body, 50 mm / min in accordance with JIS K6256-1999 A peel test between two reinforcing fiber fabrics was carried out at a speed of At this time, the adhesive strength (N / 25 mm width) is obtained from the force required for peeling, and the ratio of the adhesive strength of the evaluation body with a vulcanization time of 1440 minutes to the adhesive strength of the evaluation body with a vulcanization time of 30 minutes is the adhesive strength retention rate. Calculated as (%).

アラミド繊維：デュポン社製ケブラー繊維
Ｎ６６：６，６−ナイロン繊維
ＰＥＴ：ポリエチレンテレフタレート繊維

Aramid fiber: DuPont Kevlar fiber N66: 6,6-nylon fiber PET: Polyethylene terephthalate fiber

  From the results of Table 1 and Table 2, in the large-diameter hose using the aramid / nylon composite fiber of the present invention as a reinforcing material, the composite fiber does not undergo thermal degradation even during long-term vulcanization for 1440 minutes. It has been confirmed that the decrease in the adhesive strength due to the above has been prevented, and the elongation of the anti-adhesion heat treatment is low, and the expansion of the hose diameter can be suppressed. Therefore, even when vulcanized for a long time, the adhesive force between the rubber layer and the reinforcing material layer is sufficiently secured, and since the dimensional stability is excellent, the reinforcing effect and durability can be excellent. Recognize.

Next, Table 3 shows the results obtained by measuring the elongation (intermediate elongation) of the composite fiber fabric described in Table 1 according to the above method at a predetermined load. The results of strength and elongation at break are also shown.

From the results of Table 3 above, the PET fiber cord of Comparative Example 2 has an intermediate elongation equivalent to that of the conjugate fiber of the present invention, but the conjugate fiber cord of the present invention is superior in strength and elongation at the time of cutting. . Further, in the nylon / PET composite fiber cord of Comparative Example 6, the heat resistance is improved as compared with Comparative Example 2 using a fiber cord of only PET fibers (see Tables 1 and 2), but the intermediate elongation is The modulus of the composite fiber as a whole is low. Therefore, it can be seen that although the heat resistance is improved, the diameter of the hose is greatly enlarged during transportation of the fluid, which may cause a decrease in transportation pressure.
From the above, it was confirmed that the reinforcing material using the aramid / nylon composite fiber of the present invention was excellent in the reinforcing effect and dimensional stability.

Table 4 shows the evaluation results of the adhesive strength of an evaluation body produced by using the composite fiber fabric described in Table 1 and changing the vulcanization temperature to 155 ° C.

  From the results of Table 4 above, when the aramid / nylon composite fiber of the present invention is used, even if the vulcanization temperature is increased to 155 ° C., the adhesive force after vulcanization for a long time does not decrease and is maintained in a high state. It was confirmed that Therefore, it was confirmed that by increasing the vulcanization temperature, it is possible to shorten the vulcanization time and improve the productivity of the large-diameter hose.

Claims (7)

  In a large-diameter rubber hose formed using a vulcanized rubber reinforced by combining a fiber fabric and / or fiber cord, the fiber fabric and / or fiber cord is composed of a composite fiber of an aramid fiber and a nylon fiber. Large-diameter rubber hose characterized by   The large-diameter rubber hose according to claim 1, wherein in the composite fiber, the total fineness of the aramid fiber and the nylon fiber is 2000 to 11000 dt.   The large-diameter rubber hose according to claim 1 or 2, wherein in the composite fiber, the ratio of the fineness of the aramid fiber to the total fineness of the aramid fiber and the nylon fiber is 35 to 80%.   The large-diameter rubber hose according to any one of claims 1 to 3, wherein the aramid fiber is a para-aramid fiber.   The large diameter rubber hose according to claim 4, wherein the aramid fiber is a Kevlar fiber.   The large-diameter rubber hose according to any one of claims 1 to 5, wherein each of the composite fibers is formed by first twisting aramid fibers and nylon fibers, each having a lower twist, and having an upper twist coefficient of 1440 to 2400.   7. The composite fiber according to any one of claims 1 to 6, wherein the composite fiber is obtained by twisting aramid fiber and nylon fiber, each of which is twisted, and the number of twists is 0.5 to 1 times the number of twists. Large-diameter rubber hose as described.