Resin pipe for microducts

Abstract

To provide a resin pipe for a micro duct which is excellently inserted into an optical fiber cable and is installed.SOLUTION: For a resin pipe (1) for a micro duct in which an optical fiber cable is inserted and installed, at least an inner surface (10) is formed of a polyethylene resin containing 0.01 to 20% by mass of a non-reactive silicone.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a resin pipe for a microduct into which an optical fiber cable is inserted and laid. [Background technology]

[0002] The so-called microduct system method, in which an optical fiber cable is inserted and installed in a small-diameter microduct installed inside a large-diameter main duct, has been widely adopted in Europe and the United States because once the conduit (microduct) is installed, it is possible to add, change, or update the optical fiber cable without large-scale construction work. Generally, the microduct system method applies a method of inserting the optical fiber cable into the microduct by pressurizing it with high-pressure compressed air, or a method that combines air-pressurized pushing and solid-state pushing (see, for example, Patent Document 1).

[0003] In either method, the tube that constitutes the microduct is required to have low friction, be resistant to buckling of the cable, and have good air pumping characteristics. Conventionally, pipes and tubes for air-pressurized optical cables have been made of synthetic resins such as polyethylene (see, for example, Patent Documents 2 and 3). Patent Document 2 proposes a pipe for air-pressurized optical cables that consists of a pipe body made of synthetic resin and a spiral wire that is half-buried in the inner wall surface of the pipe body. Patent Document 3 also proposes a pipe for air-pressurized optical cables that has a Vicat softening point of 120 to 140°C and a density of 0.950 to 0.970 g / cm. 3 Olsen stiffness 7500~13000kg / cm 2 Plastic pipes made of polyethylene have been proposed. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-309519 [Patent Document 2] Japanese Patent Application Publication No. 5-323128 [Patent Document 3] Japanese Patent Application Publication No. 10-62665 Summary of the Invention [Problem to be solved by the invention]

[0005] In recent years, the distances over which optical fiber cables are inserted and installed have become longer, and so there is a demand for resin pipes for microducts that have lower friction and are easier to push in by air pressure or solid state. However, the conventional resin pipes mentioned above have poor sliding properties with the cable, making them unsuitable for long-distance installation.

[0006] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a resin pipe for a microduct that is excellent in the ability to insert and install an optical fiber cable. [Means for solving the problem]

[0007] The resin pipe for a microduct according to the present invention is a resin pipe for a microduct into which an optical fiber cable is inserted and laid, and has an outer diameter of 4 to 40 mm, an inner diameter of 2 to 38 mm, and a thickness of 1 to 3 mm, and is composed of two or more layers, with at least the innermost layer having a substantially circular cross section, Non-reactive silicone gum or non-reactive silicone rubber of 0.05~10 The outermost layer is made of polyethylene resin containing 100% by mass of polyethylene resin, and is formed in close contact with the entire surface of the layer directly below. The innermost layer has a thickness of 5 to 30% of the total thickness, and has a dynamic friction coefficient of 0.2 or less against high-density polyethylene, as measured by a friction coefficient measuring device in accordance with the method specified in JIS K7125, with the dimensions of the contact surface being 63 mm x 63 mm, the load during measurement being 50 g, and the table moving speed being 100 mm / min. The polyethylene resin may contain two or more types of polyethylene having different densities, and may contain polyethylene having at least a density of 0.91 to 0.97 g / cm 3 and polyethylene with a density of 0.91 to 0.93 g / cm 3 In this case, the polyethylene resin may contain high-density polyethylene (HDPE), low-density polyethylene (LDPE) and / or linear low-density polyethylene (LLDPE), and the content of the low-density polyethylene (LDPE) and the linear low-density polyethylene (LLDPE) may be 0.01 to 20% by mass. The outermost layer of the resin pipe for a microduct of the present invention may be formed, for example, from a polyethylene resin that does not contain non-reactive silicone. In this case, one or more intermediate layers may be provided between the innermost and outermost layers, and these intermediate layers may be formed from a polyethylene resin that does not contain non-reactive silicone. Alternatively, one or more intermediate layers may be provided between the innermost layer and the outermost layer, and the intermediate layers may be formed from a polyethylene resin that does not contain non-reactive silicone, while the outermost layer may be formed from a polyethylene resin that contains 0.01 to 20 mass% of any one selected from non-reactive silicone gum, silicone rubber, and silicone oil. The resin pipe for microducts of the present invention can have an oblateness of 10% or less, calculated by measuring the maximum and minimum values ​​of the outer diameter at any position with a vernier caliper and taking the arithmetic mean. [Effects of the Invention]

[0008] According to the present invention, the friction of the inner surface that comes into contact with the optical fiber cable can be reduced, thereby improving the performance of inserting and laying the optical fiber cable. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a cross-sectional view showing an example of the structure of a resin pipe according to an embodiment of the present invention. [Figure 2] 4A and 4B are cross-sectional views showing other structural examples of the resin pipe according to the embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0010] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the accompanying drawings. However, the present invention is not limited to the following embodiments.

[0011] The resin pipe according to an embodiment of the present invention is a resin pipe for a microduct into which an optical fiber cable is inserted and laid, and at least the inner surface is formed of a polyethylene resin containing 0.01 to 20 mass% of non-reactive silicone. The "inner surface" here refers to the hollow surface that comes into contact with the optical fiber cable. The optical fiber cable may be inserted by air pressure pushing, solid pushing, or a combination of these.

[0012] [structure] 1 and 2A and 2B are cross-sectional views showing structural examples of a resin pipe according to an embodiment of the present invention. The resin pipe according to this embodiment may have a single-layer structure consisting of only a single resin layer 11, such as resin pipe 1 shown in FIG. 1; a two-layer structure consisting of an inner layer 21 and an outer layer 22, such as resin pipe 2 shown in FIG. 2A; or a three-layer structure having an inner layer 31, an outer layer 32, and an intermediate layer 33, such as resin pipe 3 shown in FIG. 2B. The intermediate layer 33 shown in FIG. 2B may be composed of multiple layers, and may include a layer formed of a resin or material other than polyethylene.

[0013] In the case of the single-layer resin pipe 1 shown in Fig. 1, the entire resin layer 11 is formed of a polyethylene resin containing 0.01 to 20 mass% of non-reactive silicone. In the case of the two-layer resin pipe 2 shown in Fig. 2A, both the inner layer 21 and the outer layer 22 may be formed of a polyethylene resin containing 0.01 to 20 mass% of non-reactive silicone. However, from the viewpoint of suppressing increases in manufacturing costs, it is preferable to form the outer layer 22 of a polyethylene resin that does not contain non-reactive silicone. This allows for the inner surface 20 to have slidability while reducing manufacturing costs.

[0014] Furthermore, in the case of the three-layered resin pipe 3 shown in Fig. 2B, it is sufficient that at least the inner layer 31 is formed of a polyethylene resin containing 0.01 to 20 mass% of nonreactive silicone. The middle layer 33 and outer layer 32 may also be formed of a polyethylene resin containing 0.01 to 20 mass% of nonreactive silicone, but from the viewpoint of suppressing increases in manufacturing costs, it is preferable that the middle layer 33 be formed of a polyethylene resin that does not contain nonreactive silicone. On the other hand, from the viewpoint of suppressing increases in manufacturing costs, it is preferable that the outer layer 32 be formed of a polyethylene resin that does not contain nonreactive silicone, but by forming it of a polyethylene resin containing 0.01 to 20 mass% of nonreactive silicone, it is possible to impart slidability to the outer surface as well.

[0015] The sizes of the resin pipes 1, 2, and 3 can be appropriately selected depending on the specifications of the microduct, but can be, for example, an outer diameter of 4 to 40 mm, an inner diameter of 2 to 38 mm, and a thickness of 1 to 3 mm. In the case of the two-layer resin pipe 2 shown in FIG. 2A, the thickness of the inner layer 21 is preferably 1 to 50% of the total thickness (total thickness of the inner layer 21 and the outer layer 22), and more preferably 5 to 30%. In the case of the three-layer resin pipe 3 shown in FIG. 2B, the thicknesses of the inner layer 31 and the outer layer 32 are each preferably 1 to 45% of the total thickness (total thickness of the inner layer 31, the outer layer 32, and the intermediate layer 33), and more preferably 5 to 30%.

[0016] The lengths of the resin pipes 1, 2, and 3 are not particularly limited and can be appropriately selected depending on the specifications of the microduct, production facilities, etc. The inner and / or outer surfaces of the resin pipes 1, 2, and 3 may be subjected to surface treatment such as unevenness or spiraling.

[0017] [Non-reactive silicone] In the resin pipes 1, 2, and 3 of this embodiment, the polyethylene resin constituting the inner surfaces 10, 20, and 30 contains non-reactive silicone in an amount ranging from 0.01 to 20% by mass. If the non-reactive silicone content is less than 0.01% by mass, the effect of improving the sliding properties of the inner surfaces 10, 20, and 30 cannot be obtained. Furthermore, even if the content exceeds 20% by mass, further improvement in sliding properties cannot be expected, resulting in increased manufacturing costs and reduced moldability (shapeability). From the viewpoint of balancing the sliding properties of the inner surfaces 10, 20, and 30 and manufacturing costs, the amount of non-reactive silicone in the polyethylene resin is preferably 0.05 to 10% by mass.

[0018] The non-reactive silicone used in the resin pipes 1, 2, and 3 of this embodiment may be any silicone that does not have a reactive functional group, and examples thereof include non-reactive silicone gum, silicone rubber, silicone oil, and silicone powder.

[0019] [Polyethylene resin] The polyethylene resin constituting the inner surfaces 10, 20, and 30 of the resin pipes 1, 2, and 3 is not particularly limited as long as it is a resin whose main component is polyethylene, but from the viewpoint of improving sliding properties, an HDPE resin whose main component is high-density polyethylene (HDPE) is preferred. Furthermore, in the case of the single-layer resin pipe 1 shown in Fig. 1, from the viewpoint of ease of insertion of an optical fiber cable, the flexural modulus of the polyethylene resin is preferably 600 to 1800 MPa when the main component is high-density polyethylene (HDPE), 100 to 400 MPa when the main component is low-density polyethylene (LDPE), and 150 to 600 MPa when the main component is linear low-density polyethylene (LLDPE).

[0020] On the other hand, from the viewpoint of improving the dispersibility of the non-reactive silicone and imparting flexibility, it is preferable to form the inner surfaces 10, 20, 30 from a polyethylene resin containing two or more types of polyethylene with different densities. When the polyethylene resin contains two types of polyethylene, for example, 3 and polyethylene with a density of 0.91 to 0.93 g / cm 3The polyethylene may be used.

[0021] It is more preferable that the polyethylene resin constituting the inner surfaces 10, 20, and 30 contains high-density polyethylene (HDPE), low-density polyethylene (LDPE), and / or linear low-density polyethylene (LLDPE). In this case, the content of low-density polyethylene (LDPE) and linear low-density polyethylene (LLDPE) in the polyethylene resin can be appropriately selected depending on the amount of non-reactive silicone blended and the physical properties required of the resin pipes 1, 2, and 3, such as flexibility, but can be, for example, 0.01 to 20 mass%.

[0022] In the case of the two-layered resin pipe 2 shown in Fig. 2A, the polyethylene resin forming the inner layer 21 and the polyethylene resin forming the outer layer 22 may be the same or different. In the case of the three-layered resin pipe 3 shown in Fig. 2B, the polyethylene resin forming the inner layer 31, the polyethylene resin forming the outer layer 32, and the polyethylene resin forming the intermediate layer 33 may be the same or different.

[0023] The resin pipes 1, 2, and 3 of this embodiment may be appropriately colored by adding pigments or dyes to the polyethylene resin described above. Weathering agents, heat resistance agents, and the like may also be added to the polyethylene resin. Furthermore, other additives may be added to the polyethylene resin as needed, as long as they do not impair the effects of the present invention. Examples of other additives that may be added to the polyethylene resin include processing heat stabilizers, light stabilizers, UV absorbers, antioxidants, lubricants, colorants, antistatic agents, flame retardants, water repellents, waterproofing agents, hydrophilic agents, electrical conductivity agents, thermal conductivity agents, electromagnetic wave shielding agents, translucency adjusters, fluorescent agents, sliding agents, transparency agents, antiblocking agents, metal deactivators, and antibacterial agents.

[0024] As described above in detail, the resin pipe of this embodiment has at least the inner surface formed of polyethylene resin containing 0.01 to 20 mass % of non-reactive silicone, thereby reducing friction on the surface that comes into contact with the optical fiber cable and improving sliding properties. As a result, a microduct that is excellent in optical fiber cable insertion and installation performance and allows for long-distance installation can be realized. [Example]

[0025] EXAMPLES The effects of the present invention will be specifically described below with reference to Examples and Comparative Examples. In these Examples, resin pipes were produced by the following method, and their shaping properties and sliding properties were evaluated.

[0026] <Preparation of evaluation samples> (1) Raw materials Polyethylene resin A: High-density polyethylene resin Polyethylene resin B: Low-density polyethylene resin Non-reactive silicone: silicone gum

[0027] (2) How to make resin pipes The raw materials described above were blended and kneaded in the proportions shown in Table 1 below, and the resulting mixture was molded using an extruder equipped with a pipe die to obtain resin pipes of the Examples and Comparative Examples. The molding conditions were a rotation speed of 26.7 rpm, pipe die nozzle dimensions of 18 mm outer diameter and 12 mm inner diameter, and molding speed of 3 m / min. The dimensions of the resin pipe were an outer diameter of 12 mm, an inner diameter of 8 mm, and a wall thickness of 2 mm.

[0028] <Evaluation> (1)Formability The formability of the resin pipes in the examples and comparative examples was evaluated by the roundness calculated from the flattening ratio. Specifically, for each resin pipe prepared by the above-mentioned method, the maximum and minimum values ​​of the outer diameter at any position were measured with a vernier caliper, and the flattening ratio was calculated by the arithmetic mean. As a result, those with a flattening ratio of 10% or less were evaluated as acceptable (○), and those with a flattening ratio of more than 10% were evaluated as unacceptable (×).

[0029] (2) Sliding properties The kneaded material was placed in a 150 mm × 150 mm × 2 mm mold, and a load of 10 MPa was applied for 3 minutes using a hot press at 220 °C to form a sheet. The resulting sheet was cut into a 63 mm width to prepare evaluation test pieces (150 mm long, 2 mm thick). The dynamic friction coefficient of each test piece was measured according to the method specified in JIS K7125. A friction coefficient measuring device was used for the measurement, which included a table movable parallel to the installation surface, a reinforcing plate for fixing the test piece to the table, a mating material placed on the test piece, a weight for pressing the mating material against the test piece with a constant load, and a load cell connected to the mating material.

[0030] The mating material was polyethylene resin A, which was used for the test piece, and the dimensions of the contact surface of the mating material with the test piece were 63 mm x 63 mm, the weight of the weight (load during measurement) was 50 g, and the table movement speed was 100 mm / min. As a result, those with a dynamic friction coefficient of 0.2 or less were rated as pass (○), and those with a dynamic friction coefficient of more than 0.2 were rated as fail (×).

[0031] (3) Overall evaluation A sample that was evaluated as acceptable (◯) for both the shapeability and the sliding property was evaluated as passed (◯), and a sample that was evaluated as unacceptable (×) for even one of the items was evaluated as unacceptable (×). The results are shown in Table 1 below.

[0032] [Table 1]

[0033] As shown in Table 1 above, Comparative Example 1, which was made of a polyethylene resin containing no non-reactive silicone, had poor sliding properties. Furthermore, Comparative Example 2, which used a polyethylene resin containing more than 20% by mass of non-reactive silicone, had poor formability. In contrast, Comparative Example 2, which used a polyethylene resin containing 0.01 to 20% by mass of non-reactive silicone as its inner surface, had poor formability. Reference Examples 1 and 2 and Examples 3 and 4 The composition had good shaping properties and sliding properties.

[0034] From the above results, it was confirmed that the present invention can realize a resin pipe for a microduct that has excellent performance for inserting and laying optical fiber cables.

[0035] The present invention can also take the following forms. [1] A resin pipe for a microduct into which an optical fiber cable is inserted and laid, A resin pipe for a microduct, at least the inner surface of which is formed from a polyethylene resin containing 0.01 to 20% by mass of non-reactive silicone. [2] The resin pipe for microducts according to [1], wherein the polyethylene resin contains two or more types of polyethylene having different densities. [3] The resin pipe for microducts according to [1] or [2], wherein the polyethylene resin contains high-density polyethylene (HDPE) and low-density polyethylene (LDPE). [4] The resin pipe for a microduct according to any one of [1] to [3], wherein the non-reactive silicone is silicone gum, silicone rubber, silicone oil or silicone powder. [5] It consists of two layers, an inner layer and an outer layer, the inner layer is formed of a polyethylene resin containing 0.01 to 20% by mass of non-reactive silicone, The resin pipe for a microduct according to any one of [1] to [4], wherein the outer layer is formed of a polyethylene resin that does not contain non-reactive silicone. [6] It has an inner layer, a middle layer, and an outer layer, the inner layer is formed of a polyethylene resin containing 0.01 to 20% by mass of non-reactive silicone, the intermediate layer is formed of a polyethylene resin that does not contain non-reactive silicone; The resin pipe for microducts according to any one of [1] to [4], wherein the outer layer is formed of a polyethylene resin containing 0.01 to 20% by mass of non-reactive silicone or a polyethylene resin containing no non-reactive silicone. [Explanation of symbols]

[0036] 1~3 Resin pipe 10, 20, 30 inner surface 11 Resin layer 21, 31 inner layer 22, 32 outer layer 33 Middle Class

Claims

1. A resin pipe for a microduct into which an optical fiber cable is inserted and laid, The outer diameter is 4 to 40 mm, the inner diameter is 2 to 38 mm, and the thickness is 1 to 3 mm; It consists of two or more layers, At least the innermost layer has a substantially circular cross section and is formed from a polyethylene resin containing 0.05 to 10% by mass of a non-reactive silicone gum or a non-reactive silicone rubber; The outermost layer is formed in close contact with the entire surface of the layer directly below. The innermost layer is The thickness is 5 to 30% of the total thickness, The dynamic friction coefficient against high density polyethylene measured using a friction coefficient measuring device in accordance with the method specified in JIS K7125, with the contact surface dimensions of 63 mm x 63 mm, a load of 50 g during measurement, and a table movement speed of 100 mm / min, is 0.2 or less. Resin pipe for microducts.

2. The polyethylene resin contains two or more types of polyethylene having different densities, At least a density of 0.91 to 0.97 g / cm ３ and polyethylene with a density of 0.91 to 0.93 g / cm ３ The resin pipe for a microduct according to claim 1, which contains polyethylene of the formula:

3. The polyethylene resin contains high-density polyethylene (HDPE), low-density polyethylene (LDPE) and / or linear low-density polyethylene (LLDPE), and the content of the low-density polyethylene (LDPE) and the linear low-density polyethylene (LLDPE) is 0.01 to 20 mass%. The resin pipe for microducts according to claim 2.

4. A resin pipe for a microduct described in any one of claims 1 to 3, wherein the outermost layer is formed of a polyethylene resin that does not contain non-reactive silicone.

5. one or more intermediate layers are provided between the innermost layer and the outermost layer, The intermediate layer is formed of a polyethylene resin that does not contain non-reactive silicone. The resin pipe for a microduct according to claim 4.

6. one or more intermediate layers are provided between the innermost layer and the outermost layer, the intermediate layer is formed of a polyethylene resin that does not contain non-reactive silicone; The outermost layer is formed of a polyethylene resin containing 0.01 to 20% by mass of any one selected from non-reactive silicone gum, silicone rubber, and silicone oil. The resin pipe for a microduct according to any one of claims 1 to 3.

7. The resin pipe for microducts according to any one of claims 1 to 3, wherein the maximum and minimum values ​​of the outer diameter at any position are measured with a vernier caliper and the flattening ratio calculated as the arithmetic average is 10% or less.

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