Underwater flexible optical cable, composite foam material and preparation method thereof

Abstract

The invention belongs to the related field of underwater optical fiber communication technology, and discloses an underwater flexible optical cable which comprises a photoelectric unit, an inner sheath, a tensile element and an outer sheath from inside to outside, the photoelectric unit comprises an optical unit and / or an electric unit, and the optical unit and the electric unit are twisted to form a cable core; the inner sheath can be arranged outside the cable core and is made of a composite foaming material with a forming framework; the tensile element is twisted outside the inner sheath, and the outer sheath is located on the outermost layer and arranged outside the tensile element. The invention further discloses a corresponding composite foaming material and a manufacturing method thereof. According to the invention, the problem that the low density and high pressure resistance of the underwater flexible optical cable cannot be achieved at the same time is well solved, the longitudinal water pressure resistance, tensile strength and other characteristics of the optical cable are remarkably improved, and the photoelectric transmission function of underwater equipment is further ensured.

Description

Technical Field

[0001] The present invention belongs to the field related to underwater optical fiber communication technology, and more specifically, relates to an underwater flexible optical cable, a composite foaming material and a preparation method thereof. Background Art

[0002] With the rapid development of underwater communications, optical cables have achieved rapid development in underwater applications due to their light weight, small outer diameter, large transmission capacity, and good mechanical properties.

[0003] In the prior art, underwater optical cables combine optoelectronic units for underwater transmission, and usually use metal armor or multi-layer non-metal armor structures to meet the requirements of optical cable bending radius and water pressure resistance. However, different underwater applications have different requirements for optical cables. The water pressure resistance of metal armor structures can be greatly improved, but their density is relatively large. When used in deep sea, it will increase the tension requirements of the fixed end and the optical cable, and increase the system cost; although the non-metal armor structure meets the requirements of small bending radius, it mainly provides radial water pressure resistance by the sheath. The radial water pressure resistance of the optical cable meets the requirements through the sheath material, thickness and armor structure, and watertight glue is filled in the gap of the optical cable, but its radial watertight performance can only reach 6.75MPa, which is difficult to be effectively improved.

[0004] Therefore, the technical problem of underwater optical cables requiring both low density and high pressure resistance has not been effectively solved, which has led to restrictions in some application areas and it is difficult to expand the application of underwater optical cables in the short term. Once inappropriate products are used, seawater can directly reach the underwater system and the receiving equipment on the water, causing serious losses. Summary of the invention

[0005] In response to one or more of the above defects or needs of the prior art, the present invention provides an underwater flexible optical cable, a composite foam material and a preparation method thereof, wherein by arranging the foam material in the optical cable structure and making targeted improvements to its material composition, key performance indicators and action mechanism, it can ensure that the underwater flexible optical cable can also produce high-pressure-resistant products under the process requirements of high tensile strength, small bending radius, low density, etc., thereby effectively solving the problem that the underwater flexible optical cable cannot have both low density and high pressure resistance; in addition, by improving the manufacturing process of the underwater flexible optical cable, the longitudinal water pressure resistance and tensile strength of the optical cable can be significantly improved, thereby further ensuring the photoelectric transmission function of the underwater equipment.

[0006] To achieve the above object, according to a first aspect of the present invention, a composite foam material is provided, characterized in that the composite foam material is formed by foaming a foaming polymer on a molded skeleton.

[0007] Among them, by weight, the foaming polymer is 80 to 90 parts; the molding skeleton is 10 to 20 parts.

[0008] As a further preferred embodiment of the present invention, the composite foam material further comprises an interface agent, the interface agent is sprayed on the molding skeleton, and the foaming polymer is foamed on the molding skeleton through the interface agent.

[0009] The interface agent comprises:

[0010] a first molecular chain, which is molecularly entangled with the molecular chain of the foaming polymer and forms a cross-linked three-dimensional structure with the foaming polymer through intermolecular van der Waals forces during the molecular entanglement process;

[0011] The second molecular chain undergoes a complexation reaction or a chemical reaction with the molded skeleton, and forms a cross-linked three-dimensional structure with the molded skeleton through intermolecular van der Waals forces during the reaction.

[0012] As a further preferred embodiment of the present invention, the thickness of the interface agent is less than 10 μm and the surface coverage is greater than 60%. In this way, the bonding strength between the interface agent and the forming skeleton and the foaming polymer can be ensured, and the tensile strength thereof is enhanced, and the actual tensile strength is greater than 3 MPa.

[0013] As a further preferred embodiment of the present invention, the weight ratio of the interface agent is 0.1% to 10%. In this way, sufficient interface agent content can ensure sufficient reaction between the molding skeleton and the foaming polymer, ensure the thickness of the interface layer, and thus increase its interface strength.

[0014] As a further preferred embodiment of the present invention, the interface strength between the molded skeleton and the foamed polymer is not less than 3MPa. In this way, when the interface strength is high, as the inner sheath of the underwater optical cable, it can withstand more radial water pressure, matching the optical cable structure, thereby protecting the internal optical unit and ensuring the stable transmission of the optical signal.

[0015] As a further preferred embodiment of the present invention, the interface agent includes a grafted polymer, a coupling agent, etc.; the first molecular chain includes an olefin group, an ester group, a carboxyl group, an ether group, etc.; the second molecular chain includes a silane bond, a titanate bond, an amino group, a methoxy group, etc.

[0016] As a further preferred embodiment of the present invention, the foaming degree of the composite foam material is 30% to 90%, and the density is 0.6 g / cm 3 ~1.2g / cm 3 , tensile strength ≥3Mpa.

[0017] As a further preference of the present invention, the foaming polymer is polyethylene foam, polypropylene foam or a mixture of the two; the molding skeleton is one or more of a polymer skeleton, a non-metal skeleton or a light metal skeleton, wherein the polymer skeleton is one or more of polyimide, polyetherimide, and fluoroplastics, the non-metal skeleton is one or more of silica, ceramics, carbide and non-metallic minerals, and the light metal skeleton is one or more of aluminum alloy, titanium alloy, and stainless steel.

[0018] According to the second aspect of the present invention, there is also provided a method for preparing a corresponding composite foam material, the method comprising the following steps:

[0019] Mixing step: mixing the molded skeleton and the foamed polymer to form a mixture, wherein, by weight, the foamed polymer comprises 80 to 90 parts; and the molded skeleton comprises 10 to 20 parts;

[0020] Foaming step: the mixture is extruded through an extruder for foaming.

[0021] As a further preference of the present invention, before the mixing step, the method further comprises:

[0022] Interface agent spraying step: spraying the interface agent on the surface of the molded skeleton, and forming a layer of interface strengthening film on the molded skeleton.

[0023] As a further preferred embodiment of the present invention, in the interface agent spraying step, the temperature of the interface agent is 10°C to 60°C, the temperature of the molding skeleton is greater than 30°C, and the pressure of the interface agent spraying is 0.01MPa to 1Mpa.

[0024] As a further preference of the present invention, in the foaming step, the pressure range of the mixture in the barrel of the extruder is 1 MPa to 20 MPa, the extrusion temperature range is 180°C to 380°C, and the extrusion speed is 0.5 m / min to 100 m / min.

[0025] According to a third aspect of the present invention, there is also provided a low-density, high-pressure underwater flexible optical cable, which comprises, from inside to outside, an optoelectronic unit, an inner sheath, a tensile element and an outer sheath, wherein:

[0026] The optoelectronic unit comprises an optical unit and / or an electrical unit, which are twisted to form a cable core;

[0027] The inner sheath is arranged outside the cable core and is made of any one of the composite foam materials mentioned above;

[0028] The tensile element is twisted outside the inner sheath, and the outer sheath is located at the outermost layer and is arranged outside the tensile element.

[0029] As a further preferred embodiment of the present invention, in the composite foam material, the molded skeleton is used to withstand water pressure, and the foamed polymer plays a role in reducing density.

[0030] As a further preferred embodiment of the present invention, the inner layer of the cable core also includes a central reinforcement member.

[0031] As a further preferred embodiment of the present invention, for the composite foam material, the foaming polymer accounts for 80 to 90 parts by weight, and the molding skeleton accounts for 10 to 20 parts by weight.

[0032] As a further preferred embodiment of the present invention, the overall density of the composite foam material, i.e., the inner sheath, is preferably 0.6 g / cm 3 ~1.2g / cm 3 The strength is preferably ≥3Mpa, and the foaming degree is preferably 30% to 90%.

[0033] As a further preferred embodiment of the present invention, the overall thickness of the composite foam material, ie, the inner sheath, can be controlled according to the density of the optical cable, and is preferably 0.5 mm to 5 mm.

[0034] As a further preferred embodiment of the present invention, the optical cable density range is 0.9 g / m 3 ~1.5g / m 3 .

[0035] As a further preferred embodiment of the present invention, the size of the molded skeleton is 0.1 mm to 1 mm.

[0036] As a further preferred embodiment of the present invention, the molded skeleton is preferably made by using a mold and by extrusion, injection molding or casting.

[0037] As a further preferred embodiment of the present invention, the shape of the molded skeleton can be selected according to the water resistance of the optical cable, and is preferably one or more of a porous spherical shape, a tree branch shape, and a hollow three-dimensional shape.

[0038] As a further preferred embodiment of the present invention, the size of the molded skeleton can be selected according to the water resistance of the optical cable, and is preferably 0.1 mm to 1 mm.

[0039] As a further preferred embodiment of the present invention, the gaps in the underwater flexible optical cable are filled with watertight glue, and the filling rate of the watertight glue in the gaps in the optical cable is preferably above 90%.

[0040] As a further preferred embodiment of the present invention, the watertight glue is preferably coated on the surface of at least one substrate in the underwater flexible optical cable.

[0041] According to a fourth aspect of the present invention, there is provided a method for manufacturing a low-density and high-pressure underwater flexible optical cable, the method comprising the following steps:

[0042] Twisting optical units and / or electrical units to form a cable core;

[0043] selectively wrapping a wrapping tape around the outside of the cable core;

[0044] A mixture of any one of the aforementioned composite foam materials is foamed and extruded outside the wrapping tape or directly outside the cable core by an extruder to form an inner sheath;

[0045] twisting a tensile element outside the inner sheath;

[0046] An outer sheath is arranged outside the tensile element.

[0047] As a further preferred embodiment of the present invention, the molded skeleton is used to withstand water pressure, and the foamed polymer plays a role in reducing density.

[0048] As a further preferred embodiment of the present invention, in the above manufacturing process, a watertight glue is coated on the surface of at least one substrate in the underwater flexible optical cable.

[0049] As a further preferred embodiment of the present invention, when applying the watertight glue, it is preferred to maintain the corresponding substrate temperature between 15° C. and 35° C., and the glue injection pressure is 0.5 MPa to 1.5 MPa.

[0050] As a further preferred embodiment of the present invention, the coating thickness of the watertight glue is preferably greater than 0.5 mm.

[0051] In general, the above technical solution conceived by the present invention has the following technical advantages compared with the prior art:

[0052] (1) The present invention arranges a composite foam material in the structure of the underwater flexible optical cable and makes targeted improvements to its basic working mechanism, thereby utilizing the low-density characteristics of the foamed polymer, the supporting characteristics of the molded skeleton, and the bonding force between the two, thereby significantly improving the water pressure resistance of the underwater flexible optical cable while reducing the overall cable density. Accordingly, the technical problem that the underwater flexible optical cable cannot have both low density and high pressure resistance in the prior art is solved;

[0053] (2) The present invention also optimizes the specific composition, proportion of ingredients, and some key performance indicators such as skeleton type, skeleton content, skeleton shape and size, interface agent type, interface strength, and foaming degree of the composite foam material, and accordingly obtains a flexible optical cable product that is more suitable for underwater application scenarios; for example, when polyethylene and dendritic non-metal are used as the foaming polymer and the molding skeleton respectively, and chloropropyltrimethoxy is added thereto as an interface agent, the final density can be controlled at 0.8 g / cm 3 Optical cable products with a pressure resistance of more than 10MPa;

[0054] (3) The present invention fills the gaps of the underwater flexible optical cable with watertight glue, which expands after absorbing water to fully fill the gaps. At the same time, due to the high bonding strength between the watertight glue and the substrate, the watertight glue and the substrate do not fall off under high water pressure conditions, and due to the high bonding strength, it has high stability under high water pressure conditions. Accordingly, the underwater flexible optical cable of the present invention can protect the equipment at both ends when used in deep water because its inner sheath plays the role of radial water pressure resistance and low density, thereby reducing the risk of use.

[0055] (4) The present invention further improves the coating position of the watertight glue and key processing parameters in the manufacturing process. Since part or all of the central reinforcement member, the optical unit, the electrical unit, the wrapping tape, and the tensile element are coated with watertight glue, when the optical unit and the electrical unit are twisted and the tensile element is twisted, the gaps are filled with watertight glue under the pressure of the glue injection system, which can ensure that the gaps in the optical cable are filled with sufficient watertight glue. The higher the watertight glue filling rate, the smaller the gaps between the optical cable substrates, and the greater the water absorption expansion ratio. Once water is absorbed, the watertight glue can expand and fill these gaps.

[0056] (5) The underwater flexible optical cable of the present invention has an inner sheath made of a composite foam material in its structure. At the same time, the inner sheath has the low density characteristics of the foamed polymer, the high support characteristics of the molded skeleton, and the high interface bonding force between the two. Many actual tests have shown that the optical cable can withstand the pressure of more than 200m underwater, and its maximum radial water pressure performance can reach 20MPa. In addition, the optical cable does not have any metal layer, has better flexibility, and has better longitudinal water pressure resistance and high tensile strength than existing similar products. It can be repeatedly retracted and extended to meet the requirements of a small bending radius. It can be used in various submarine environments with complex working conditions to ensure the photoelectric transmission of underwater equipment, and thus has good practical value and application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Figure 1 is a structural cross-sectional view of an underwater flexible optical cable according to a preferred embodiment of the present invention;

[0058] Figure 2is a flow chart for exemplarily illustrating the method for manufacturing an underwater flexible optical cable of the present invention;

[0059] In all drawings, the same reference numerals are used to denote the same elements or structures, specifically:

[0060] 1-Central reinforcement; 2-Electrical unit; 3-Optical unit; 4-Tape; 5-Inner sheath; 6-Tensile element; 7-Outer sheath; 8-Watertight glue. DETAILED DESCRIPTION

[0061] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. In addition, the technical features involved in each embodiment of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0062] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0063] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0064] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0065] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0066] Figure 1 1 is a cross-sectional view of the structure of an underwater flexible optical cable according to a preferred embodiment of the present invention, which will be referred to below. Figure 1 To explain the present invention in more detail.

[0067] See also Figure 1 According to a preferred embodiment of the present invention, the underwater flexible optical cable may include an optoelectronic unit, an inner sheath 5, a tensile element 6 and an outer sheath 7 from the inside to the outside, and may also include a central reinforcement member 1 in the innermost layer, that is, the central reinforcement member 1 may exist alone or be replaced by an optoelectronic unit, wherein:

[0068] The optoelectronic unit comprises an optical unit 3 and / or an electrical unit 2, that is, a single optical unit, an electrical unit or a combination of the two, which are twisted around the central reinforcement member 1 to form a cable core;

[0069] The wrapping tape 4 is an optional structure, which is wrapped around the outside of the cable core. The inner sheath 5 is correspondingly arranged on the outside of the wrapping tape 4 and is made of a composite foam material, which is a mixture of a foaming polymer and a molding skeleton, wherein the molding skeleton is used to withstand water pressure, and the foaming polymer plays a role in reducing density;

[0070] The tensile element 6 is twisted on the outside of the inner sheath 5 , and the outer sheath 7 is located at the outermost layer and is arranged on the outside of the tensile element 6 by, for example, extrusion molding.

[0071] According to a preferred embodiment of the present invention, for the composite foam material, the foaming polymer accounts for 80 to 90 parts by weight, and the forming skeleton accounts for 10 to 20 parts by weight.

[0072] According to another preferred embodiment of the present invention, the overall density of the composite foam material, i.e., the inner sheath, is preferably 0.6 g / cm 3 ~1.2g / cm 3 ; Its strength is ≥3MPa, and more preferably between 6MPa and 7MPa; The foaming degree is designed to be 30% to 90%, and preferably ≥80%.

[0073] According to another preferred embodiment of the present invention, the thickness of the composite foam material can be controlled according to the density requirement of the optical cable, and the overall thickness of the composite foam material, ie, the inner sheath, is 0.5 mm to 5 mm, and more preferably about 2 mm.

[0074] According to another preferred embodiment of the present invention, the composite foam material can select the type of skeleton according to the water pressure resistance requirement, and the foam skeleton can select one or more of a polymer skeleton, a non-metal skeleton or a light metal skeleton; wherein the polymer skeleton is preferably one or more of polyimide, polyetherimide, and fluoroplastic, the non-metal skeleton is preferably one or more of silica, ceramics, carbide, and non-metallic minerals, and the light metal skeleton is preferably one or more of aluminum alloy, titanium alloy, and stainless steel.

[0075] According to another preferred embodiment of the present invention, the composite foam material can select a skeleton shape according to the water pressure resistance requirement, and the molded skeleton can select one or more of a porous spherical shape, a tree branch shape, and a hollow three-dimensional shape; in addition, the composite foam material can select a skeleton size according to the water pressure resistance requirement, and the size of the molded skeleton is preferably 0.1mm to 1mm, and more preferably about 0.3mm.

[0076] According to another preferred embodiment of the present invention, the type of the foaming polymer is preferably polyethylene foam, polypropylene foam or a mixture of the two. According to another preferred embodiment of the present invention, an interface agent is preferably added to the composite foam material, and the interface agent is used to strengthen the interface strength between the molded skeleton and the foamed polymer, thereby further improving the water pressure resistance of the entire optical cable. More specifically, the interface agent can be selected from grafted polymers, coupling agents, etc. The first molecular chain in the interface agent, such as olefin groups, ester groups, carboxyl groups, ether groups, etc., is combined with the foaming polymer molecular chain through molecular entanglement to form a molecular level cross-linked structure. At the same time, the second molecular chain of the interface agent forms a metal complex through chemical reaction or forms a metal complex, and forms a cross-linked three-dimensional structure with the molded skeleton through intermolecular van der Waals forces during the reaction process, thereby improving the bonding force between the foaming polymer and the molded skeleton.

[0077] According to another preferred embodiment of the present invention, the gap of the underwater flexible optical cable is filled with watertight glue 8. For example, the gap between the central reinforcement member and the wrapping tape can be filled with watertight glue, or / and the gap between the wrapping tape and the inner sheath, and the gap between the tensile element and the outer sheath can be filled with watertight glue.

[0078] According to another preferred embodiment of the present invention, the filling rate of the watertight glue in the gap of the optical cable is above 90%, preferably above 98%.

[0079] Figure 2This is a flow chart for exemplifying the method for making an underwater flexible optical cable of the present invention. Figure 2 To explain the underwater flexible optical cable manufacturing process of the present invention in more detail.

[0080] First, the optical unit and the electrical unit are twisted together around a central reinforcement member to form a cable core, or the optical unit and the electrical unit are directly twisted together to form a cable core;

[0081] Next, wrapping a wrapping tape around the outside of the cable core;

[0082] Next, on the outside of the wrapping tape, a composite foam material is used to form an inner sheath in a foaming manner, wherein the composite foam material is a mixture of a foaming polymer and a molding skeleton, wherein the molding skeleton is used to withstand water pressure, and the foaming polymer plays a role in reducing density;

[0083] Next, a tensile element is twisted outside the inner sheath;

[0084] Finally, an outer sheath is arranged outside the tensile element.

[0085] More specifically, according to a preferred embodiment of the present invention, in the process of forming the inner sheath by foaming the composite foam material, a small amount of interface agent is preferably added to strengthen the interface strength between the molded skeleton and the foamed polymer.

[0086] According to another preferred embodiment of the present invention, the interface agent is preferably coated on the surface of the molding skeleton by spraying, and the interface strength between the molding skeleton and the foaming polymer reaches above 3 MPa.

[0087] According to another preferred embodiment of the present invention, in the above-mentioned manufacturing process, it is preferred that a surface of at least one substrate in the underwater flexible optical cable, i.e., at least one of the central reinforcement, optical unit, electrical unit, wrapping tape, and tensile element is coated with watertight glue, or in the manufacturing process, each layer of substrate is provided and its surface is coated with watertight glue.

[0088] According to another preferred embodiment of the present invention, during coating, the corresponding substrate temperature is preferably maintained between 15 and 35° C., and the coating thickness is greater than 0.5 mm.

[0089] According to another preferred embodiment of the present invention, when injecting the watertight glue, the injection pressure is preferably set to 0.5 MPa to 1.5 MPa.

[0090] The present invention also provides a corresponding composite foam material, characterized in that the composite foam material is formed by foaming a foaming polymer on a forming skeleton.

[0091] Among them, by weight, the foaming polymer is 80 to 90 parts; the molding skeleton is 10 to 20 parts.

[0092] According to a preferred embodiment of the present invention, the composite foam material further comprises an interface agent, the interface agent is sprayed on the molding skeleton, and the foaming polymer is foamed on the molding skeleton through the interface agent.

[0093] The interface agent comprises:

[0094] A first molecular chain, which can be molecularly entangled with the molecular chain of the foaming polymer and form a cross-linked three-dimensional structure with the foaming polymer through intermolecular van der Waals forces during the molecular entanglement process;

[0095] The second molecular chain can undergo a complexation reaction or a chemical reaction with the molded skeleton, and during the reaction process, form a cross-linked three-dimensional structure with the molded skeleton through intermolecular van der Waals forces.

[0096] According to another preferred embodiment of the present invention, the thickness of the interface agent is less than 10 μm and the surface coverage is greater than 60%;

[0097] And / or, the weight ratio of the interface agent is 0.1% to 10%;

[0098] And / or, the interface strength between the molded skeleton and the foamed polymer is not less than 3 MPa.

[0099] According to another preferred embodiment of the present invention, the interface agent includes a grafted polymer, a coupling agent, etc.; the first molecular chain includes an olefin group, an ester group, an ester group, a carboxyl group, an ether group, etc.; the second molecular chain includes a silane bond, a titanate, an amine group, etc.

[0100] According to another preferred embodiment of the present invention, the foaming degree of the composite foam material is 30% to 90%, and the density is 0.6 g / cm 3 ~1.2g / cm 3 , tensile strength ≥3Mpa.

[0101] According to another preferred embodiment of the present invention, the foaming polymer is polyethylene foam, polypropylene foam or a mixture of the two; the molding skeleton is one or more of a polymer skeleton, a non-metal skeleton or a light metal skeleton, wherein the polymer skeleton is one or more of polyimide, polyetherimide, and fluoroplastics, the non-metal skeleton is one or more of silica, ceramics, carbide and non-metallic minerals, and the light metal skeleton is one or more of aluminum alloy, titanium alloy, and stainless steel.

[0102] The present invention also provides a method for preparing the corresponding composite foam material, which comprises the following steps:

[0103] Mixing step: mixing the molded skeleton and the foamed polymer to form a mixture, wherein, by weight, the foamed polymer comprises 80 to 90 parts; and the molded skeleton comprises 10 to 20 parts;

[0104] Foaming step: the mixture is extruded through an extruder for foaming.

[0105] According to a preferred embodiment of the present invention, before the mixing step, the method further comprises the following steps:

[0106] Interface agent spraying step: spraying the interface agent on the surface of the molded skeleton, and forming a layer of interface strengthening film on the molded skeleton.

[0107] According to another preferred embodiment of the present invention, in the interface agent spraying step, the temperature of the interface agent is 10°C to 60°C, the temperature of the molded skeleton is greater than 30°C, and the pressure of the interface agent spraying is 0.01MPa to 1Mpa.

[0108] According to another preferred embodiment of the present invention, in the foaming step, the pressure of the mixture in the barrel of the extruder is in the range of 1 MPa to 20 MPa, the extrusion temperature is in the range of 180°C to 380°C, and the extrusion speed is in the range of 0.5 m / min to 100 m / min.

[0109] In order to better understand the products, applications and preparation methods of the present invention, the following specific examples are provided.

[0110] Embodiment 1:

[0111] In this embodiment, the formula of the composite foam material is as follows, by weight: the foaming polymer is polyethylene foam material, with a weight of 80 parts; the molding skeleton is polyimide polymer, with a weight of 20 parts, the shape is tree-like, and the size is about 0.3 mm; the above-mentioned foaming polymer and the molding skeleton are mixed and foamed, and a grafted polymer is added as an interface agent, wherein the grafted polymer is specifically a copolymer of α-olefin and alkenyl silane, and has a first molecular chain of olefin group and a second molecular chain of silane bond, with a thickness of about 8 μm, a surface coverage of 65%, and a weight ratio of 1%.

[0112] The interface agent is first sprayed on the surface of the molding skeleton to form an interface strengthening film. During the operation, the temperature of the interface agent is controlled at 10°C, the temperature of the molding skeleton is 35°C, and the interface agent spraying pressure is 0.01MPa; followed by a foaming step, during which the pressure range of the above mixture in the barrel of the extruder is 1 MPa, the extrusion temperature range is 180°C, and the extrusion speed is 0.5m / min.

[0113] After the reaction, the desired inner sheath material is obtained, wherein the thickness of the inner sheath is controlled to be 0.5 mm, and the foaming degree is measured to be 30%, and the overall density of the inner sheath is 0.6 g / cm 3 The overall tensile strength is about 4MPa. The density of the final optical cable product is 0.9g / cm3, and the radial water pressure resistance can reach 5MPa.

[0114] Example 2

[0115] In this embodiment, the formula of the composite foam material is as follows: the foaming polymer is polyethylene foam material, which is 90 parts by weight; the molding skeleton is polyetherimide polymer, which is 10 parts by weight, has a tree-like shape and a size of about 1 mm; the foaming polymer and the molding skeleton are mixed and foamed, and a grafted polymer is added as an interface agent, wherein the grafted polymer is, for example, o-hydroxyphenylethylamine, and has a first molecular chain of a carboxyl group and a second molecular chain of an amine group, and has a thickness of about 6 μm, a surface coverage of 70%, and a weight ratio of 5%.

[0116] The interface agent is first sprayed on the surface of the molding skeleton to form an interface strengthening film. During the operation, the temperature of the interface agent is controlled at 30°C, the temperature of the molding skeleton is 40°C, and the interface agent spraying pressure is 0.1MPa; followed by a foaming step, during which the pressure range of the above mixture in the barrel of the extruder is 5 MPa, the extrusion temperature range is 250°C, and the extrusion speed is 5m / min.

[0117] After the reaction, the desired inner sheath material is obtained, wherein the thickness of the inner sheath is controlled to be 1 mm, and the foaming degree is measured to be 60%, and the overall density of the inner sheath is 0.9 g / cm 3 The overall tensile strength is about 6MPa. The density of the final optical cable product is 1.0g / cm3, and the radial water pressure resistance can reach 7MPa.

[0118] Example 3

[0119] In this embodiment, the formula of the composite foam material is as follows: the foaming polymer is 85 parts by weight of polypropylene foaming material; the molding skeleton is 15 parts by weight of silicon dioxide, the shape is porous round, and the size is about 0.5 mm; the above-mentioned foaming polymer and the molding skeleton are mixed and foamed, and a coupling agent is added as an interface agent, wherein the coupling agent is specifically, for example, trimethoxy chloropropyl, and has a first molecular chain of an olefin group and a second molecular chain of a methoxy group, its thickness is about 8 μm, the surface coverage is 80%, and the weight ratio of the interface agent is 0.8%.

[0120] The interface agent is first sprayed on the surface of the molding skeleton to form an interface reinforcement film. During the operation, the interface agent temperature is controlled at 50°C, the molding skeleton temperature is 40°C, and the interface agent spraying pressure is 0.5MPa; followed by a foaming step, during which the pressure range of the above mixture in the barrel of the extruder is 10 MPa, the extrusion temperature range is 200°C, and the extrusion speed is 20m / min.

[0121] After the reaction, the required inner sheath material is obtained, wherein the inner sheath thickness is controlled to be 2 mm, and the foaming degree is measured to be 70%. The overall density of the inner sheath is 1.0 g / cm3, and the overall tensile strength is about 8 MPa. The final optical cable product has a density of 1.1 g / cm3 and a radial water pressure resistance of 12 MPa.

[0122] Example 4

[0123] In this embodiment, the formula of the composite foam material is as follows, by weight: the foaming polymer is a polypropylene foam material, with a weight of 90 parts; the molding skeleton is a ceramic, with a weight of 10 parts, a porous round shape, and a size of about 0.3 mm; the foaming polymer and the molding skeleton are mixed and foamed, and a coupling agent is added as an interface agent, and the coupling agent is specifically, for example, a phthalate ester, and has a first molecular chain and a second molecular chain, wherein the ester group as the first molecular chain is entangled with the carbon-hydrogen bond in the foaming polymer, and the phthalic acid bond as the second molecular chain chemically reacts with the silicon-oxygen bond in the ceramic, wherein the thickness of the interface agent is 6 μm, the surface coverage is 90%, and the weight ratio of the interface agent is 1.2%.

[0124] The interface agent is first sprayed on the surface of the molding skeleton to form an interface strengthening film. During the operation, the temperature of the interface agent is controlled at 60°C, the temperature of the molding skeleton is 40°C, and the interface agent spraying pressure is 1MPa; followed by a foaming step, during which the pressure range of the above mixture in the barrel of the extruder is 20 MPa, the extrusion temperature range is 380°C, and the extrusion speed is 100m / min.

[0125] After the reaction, the desired inner sheath material is obtained, wherein the thickness of the inner sheath is controlled to be 0.5 mm, and the foaming degree is measured to be 60%, and the overall density of the inner sheath is 1.2 g / cm 3 The overall tensile strength is about 10MPa. The final optical cable product density is 1.5g / cm3 and the radial water pressure resistance is 14MPa.

[0126] Embodiment 5:

[0127] In this embodiment, the formula of the composite foam material is as follows, by weight: the foaming polymer is polyethylene foam material, with a weight of 80 parts; the molding skeleton is lightweight aluminum alloy, with a weight of 20 parts, and the shape is tree-like, with a size of about 0.2 mm; the foaming polymer and the molding skeleton are mixed and foamed, and an etheramine polymer dissolved in an ethanol solvent is added as an interface agent, wherein the ether group of the interface agent is intertwined with the carbon-hydrogen bond in the foaming polymer polyethylene as the first molecular chain, and the amine group is complexed with the metal in the aluminum alloy as the second molecular chain to form a complex, the thickness of which is about 8 μm, the surface coverage is 65%, and the weight ratio is 1%.

[0128] The interface agent is first sprayed on the surface of the molding skeleton to form an interface strengthening film. During the operation, the interface agent temperature is controlled at 60°C, the molding skeleton temperature is 45°C, and the interface agent spraying pressure is 1MPa; followed by a foaming step, during which the pressure range of the above mixture in the barrel of the extruder is 5 MPa, the extrusion temperature range is 350°C, and the extrusion speed is 60m / min.

[0129] After the reaction, the desired inner sheath material was obtained, wherein the thickness of the inner sheath was controlled to be 5 mm, and the foaming degree was measured to be 90%, and the overall density of the inner sheath was 1.1 g / cm 3 The overall tensile strength is about 4MPa. The density of the final optical cable product is 1.2g / cm3 and the radial water pressure resistance is 8MPa.

[0130] Embodiment 6:

[0131] In this embodiment, the formula of the composite foam material is as follows, by weight: the foaming polymer is polyethylene foam material, with a weight of 80 parts; the molding skeleton is lightweight aluminum alloy, with a weight of 20 parts, a tree-like shape, and a size of about 0.2 mm; the foaming polymer and the molding skeleton are mixed and foamed, and an etheramine polymer dissolved in an ethanol solvent is added as an interface agent, wherein the ether group of the interface agent is intertwined with the carbon-hydrogen bond in the foaming polymer polyethylene as the first molecular chain, and the amine group is complexed with the metal in the aluminum alloy as the second molecular chain to form a complex, wherein the thickness of the interface agent is 8 μm, the surface coverage is 80%, and the weight ratio of the interface agent is 0.6%.

[0132] The interface agent is first sprayed on the surface of the molding skeleton to form an interface strengthening film. During the operation, the temperature of the interface agent is controlled at 60°C, the temperature of the molding skeleton is 45°C, and the interface agent spraying pressure is 0.8MPa; followed by a foaming step, during which the pressure range of the above mixture in the barrel of the extruder is 5 MPa, the extrusion temperature range is 180°C, and the extrusion speed is 0.5m / min.

[0133] After the reaction, the required inner sheath material is obtained, wherein the inner sheath thickness is controlled to be 3mm, and the foaming degree is measured to be 60%. The overall density of the inner sheath is 1g / cm3, and the overall tensile strength is about 8MPa. The final optical cable product has a density of 1.05g / cm3 and a radial water pressure resistance of 18MPa.

[0134] The following is a detailed description of the method for making an underwater flexible optical cable of the present invention, which may include the following steps:

[0135] A 1.5mm diameter shielded twisted pair, four 1.2mm optical units, four 0.6mm 2 The electrical unit is placed on the pay-off frame, the pay-off tension is 5N, and the cable core is twisted by the twisting machine. During the twisting, watertight glue is filled through the glue injection system, and the injection pressure is 0.5MPa.

[0136] Wrap a layer of non-woven tape with a thickness of 0.25mm and a width of 10mm around the cable core, then place it on a pay-off rack with a pay-off tension of 20N, and extrude a layer of inner sheath on the tape; foaming is performed during the extrusion process of the inner sheath, a high-density polyethylene foaming agent is selected for the inner sheath, and a porous spherical skeleton is added, with a skeleton ratio of 20%.

[0137] The zones from the feed port to the die of the extruder are set in sequence as: feed port, barrel zone 1, barrel zone 2, barrel zone 3, barrel zone 4, barrel zone 5, machine neck and die, and the temperature of each zone is set as follows: feed port 120±5℃, barrel zone 1 155±10℃, barrel zone 2 160±10℃, barrel zone 3 175±10℃, barrel zone 4 185±10℃, barrel zone 5 190±10℃, machine neck and die 195±10℃; the cooling area set at the die outlet adopts segmented cooling, the first cooling section connected to the die adopts a warm water cooling tank with a cooling temperature of 50±10℃, and the remaining sections are cooled by normal temperature water.

[0138] Twenty-four 3220dtex aramid fibers (tensile elements) are twisted outside the inner sheath. When the aramid fibers are twisted, watertight glue is filled through the glue injection system, and the injection pressure is 0.6MPa.

[0139] After the glue is injected, it enters the extruder through the guide wheel for extrusion molding of the outer sheath; the zones from the extruder material port to the die are set in sequence as follows: feed port, barrel zone 1, barrel zone 2, barrel zone 3, barrel zone 4, barrel zone 5, machine neck and die, and the temperature of each zone is set as follows: feed port is 150±5℃, barrel zone 1 is 165±10℃, barrel zone 2 is 180±10℃, barrel zone 3 is 195±10℃, barrel zone 4 is 195±10℃, barrel zone 5 is 205±10℃, machine neck and die are 205±10℃; the cooling area set at the die outlet adopts segmented cooling, the first cooling section connected to the die adopts a warm water cooling tank with a cooling temperature of 50±10℃, and the remaining sections are cooled by normal temperature water.

[0140] Finally, the watertight glue is cured at a temperature of 15 to 35° C. for 5 to 10 hours to produce the required underwater flexible optical cable.

[0141] In summary, the underwater flexible optical cable according to the present invention sets a foaming material in the optical cable structure and makes targeted improvements to its basic working mechanism, and further optimizes the specific composition, proportion of ingredients, and some key performance indicators of the composite foaming material, which accordingly solves the problem that the underwater flexible optical cable in the prior art cannot have both low density and high pressure resistance, and can obtain a flexible optical cable product that is more suitable for underwater application scenarios; in addition, the present invention can ensure high stability under high water pressure conditions by filling the gap of the underwater flexible optical cable with watertight glue in an appropriate manner, and further improve its longitudinal water pressure resistance. The underwater flexible optical cable according to the present invention does not have any metal layer, has better flexibility, and has better longitudinal water pressure resistance, high tensile strength and other characteristics compared with existing similar products. It can be repeatedly retracted and released, and can be used in various complex working conditions in the seabed environment to ensure the photoelectric transmission of underwater equipment, so it has good practical value and application prospects.

[0142] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A composite foam material, characterized in that: The composite foam material is formed by foaming a foaming polymer on a forming skeleton. Among them, by weight, the foaming polymer is 80 to 90 parts; the molding skeleton is 10 to 20 parts.

2. The composite foam material according to claim 1, characterized in that: The composite foaming material further comprises an interface agent, which is sprayed on the molding skeleton, and the foaming polymer is foamed on the molding skeleton through the interface agent. The interface agent comprises: a first molecular chain, which is molecularly entangled with the molecular chain of the foaming polymer and forms a cross-linked three-dimensional structure with the foaming polymer through intermolecular van der Waals forces during the molecular entanglement process; The second molecular chain undergoes a complexation reaction or a chemical reaction with the molded skeleton, and forms a cross-linked three-dimensional structure with the molded skeleton through intermolecular van der Waals forces during the reaction.

3. The composite foam material according to claim 2, characterized in that: The thickness of the interface agent is less than 10 μm and the surface coverage is greater than 60%; and / or, The weight ratio of the interface agent is 0.1% to 10%; and / or, The interface strength between the molded skeleton and the foamed polymer is not less than 3MPa; and / or, The composite foam material has a foaming degree of 30% to 90% and a density of 0.6 g / cm 3 ~1.2g / cm 3 , tensile strength ≥3Mpa.

4. The composite foam material according to claim 2, characterized in that: The interface agent includes a grafted polymer, a coupling agent, etc.; wherein the first molecular chain includes an olefin group, an ester group, a carboxyl group, an ether group, etc.; and the second molecular chain includes a silane bond, a titanate bond, an amine group, etc.

5. The composite foam material according to any one of claims 1 to 4, characterized in that: The foaming polymer is polyethylene foam, polypropylene foam or a mixture of the two; the molding skeleton is one or more of a polymer skeleton, a non-metal skeleton or a light metal skeleton, wherein the polymer skeleton is one or more of polyimide, polyetherimide, and fluoroplastics; the non-metal skeleton is one or more of silicon dioxide, ceramics, carbide, and non-metallic minerals; and the light metal skeleton is one or more of aluminum alloy, titanium alloy, and stainless steel.

6. A method for preparing a composite foam material according to any one of claims 1 to 5, characterized in that: The following steps are involved: Mixing step: mixing the molded skeleton and the foamed polymer to form a mixture, wherein, by weight, the foamed polymer comprises 80 to 90 parts; and the molded skeleton comprises 10 to 20 parts; Foaming step: the mixture is extruded through an extruder for foaming.

7. A method for preparing a composite foam material as claimed in claim 6, characterized in that: Before the mixing step, the method further comprises: Interface agent spraying step: spraying the interface agent on the surface of the molded skeleton, and forming a layer of interface strengthening film on the molded skeleton.

8. The method for preparing a composite foam material according to claim 6 or 7, characterized in that: In the interface agent spraying step, the temperature of the interface agent is 10° C. to 60° C., the temperature of the molded skeleton is greater than 30° C., and the pressure of the interface agent spraying is 0.01 MPa to 1 MPa; and / or, In the foaming step, the pressure of the mixture in the chamber of the extruder is in the range of 1 MPa to 20 MPa, the extrusion temperature is in the range of 180° C. to 380° C., and the extrusion speed is in the range of 0.5 m / min to 100 m / min.

9. An underwater flexible optical cable, characterized in that: The optical cable comprises, from the inside to the outside, an optoelectronic unit, an inner sheath (5), a tensile element (6) and an outer sheath (7), wherein: The optoelectronic unit comprises an optical unit (3) and / or an electrical unit (2), which are twisted to form a cable core; The inner sheath (5) is arranged outside the cable core and is made of the composite foam material according to any one of claims 1 to 5; The tensile element (6) is twisted outside the inner sheath (5), and the outer sheath (7) is located at the outermost layer and is arranged outside the tensile element (6).

10. The underwater flexible optical cable according to claim 9, characterized in that: The composite foam material, i.e. the inner sheath (5), has a thickness of 0.5 mm to 5 mm, and / or The optical cable density range is 0.9g / m 3 ~1.5g / m 3 , and / or, The size of the molded skeleton is 0.1 mm to 1 mm, and / or, The shape of the molded skeleton is one or more of a porous spherical shape, a branch shape, and a hollow three-dimensional shape.

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