Basalt fiber cloth reinforced basalt fiber felt composite heat insulation felt for fireproof cable as well as preparation method and application of basalt fiber cloth reinforced basalt fiber felt composite heat insulation felt

Abstract

The invention relates to a composite heat insulation felt of basalt fiber cloth reinforced basalt fiber felt for a fireproof cable and a preparation method and application of the composite heat insulation felt, and relates to the technical field of fireproof heat insulation materials, the preparation method comprises the following steps: pretreating basalt fibers to obtain first basalt fibers; the basalt fiber cloth is clamped between the two lapping layers of the first basalt fibers, then needling, cutting and rolling are conducted, and the basalt fiber cloth reinforced basalt fiber needled felt is obtained; and adding the basalt fiber cloth reinforced basalt fiber needled felt into a silicon dioxide sol precursor hydrolysate, and carrying out dipping treatment to obtain the basalt fiber cloth reinforced basalt fiber needled felt composite silicon dioxide sol. The basalt fiber cloth reinforced basalt fiber felt composite heat insulation felt for the fireproof cable provided by the invention has the characteristics of high tensile strength, moisture resistance, water resistance, low high thermal conductivity coefficient, no cracking at high temperature, no pulverization and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of fireproof and heat-insulating materials, and in particular to a composite heat-insulating felt of basalt fiber cloth reinforced basalt fiber felt for fireproof cables, and a preparation method and application thereof. Background Art

[0002] At present, fireproof cables are mainly composed of conductors, insulating layers, heat-insulating fire-resistant layers, inorganic filling layers, fire-blocking layers, outer sheaths, etc. Among them, mineral insulated fireproof cables are mainly composed of seamless copper sheaths, copper rod conductors, and magnesium oxide insulating powder filled between the copper conductor and the sheath. The copper rod is fixed in the copper tube by a positioner, and magnesium oxide powder / pre-assembled magnesium oxide porcelain columns are filled, sealed, pre-rolled, drawn, fine-rolled, straightened, tempered, inspected, and rolled. However, due to the limited length of seamless copper tubes, the length of inorganic mineral fireproof insulation cables usually prepared is about 100m, resulting in a large number of intermediate joints in large-scale cable laying. In addition, magnesium oxide powder is easy to absorb moisture and become magnesium hydroxide, resulting in a serious decrease in the insulation of the cable. Magnesium oxide powder needs to be dehumidified and dried before filling, and the cable construction joints need to be strictly moisture-proof and waterproof. The prepared cable has high rigidity, and the specific gravity of magnesium oxide powder is 2.2-2.6. The prepared mineral insulated fireproof cable has a high density.

[0003] Ceramic silicone rubber flexible fireproof cable uses silicone rubber that can be sintered and ceramicized at high temperature as the thermal insulation material, fire-resistant mica tape as the insulation layer, filled with inorganic magnesium hydroxide / aluminum hydroxide composite polyolefin material as the cooling and oxygen-insulating layer, and the outer sheath uses a cross-linked polyethylene low-smoke non-toxic flame-retardant extruded sheath. When a fire occurs in the cable, the ceramicized inorganic powder (zinc borate, mica powder, montmorillonite, low-melting point glass powder, kaolin, etc.) in the ceramic silicone rubber is heated, melted, sintered and ceramicized, forming a hard and porous shell on the outside of the cable, thereby isolating the heat and flame from further damaging the internal insulation layer of the cable, and then causing insulation failure. However, ceramic silicone rubber begins to form an insulating shell at 500-600℃, and the insulating shell is further ceramicized at 600-800℃. However, silicone rubber will produce a certain amount of smoke during the heating process, and the formed insulating shell has a low strength, and is easy to peel off from the cable surface under impact. The thermal conductivity of the insulating shell is high (greater than 0.2W / m·K), and the thermal insulation effect is poor. In order to improve the problem of low strength of ceramic silicone rubber shell under heating, a layer of glass fiber reinforced wrapping tape is usually wrapped outside the ceramic silicone rubber insulation layer. The structure of ceramic silicone rubber fireproof flexible cable is relatively complex, and it is necessary to add a cooling oxygen insulation layer and glass fiber reinforced wrapping tape. Some products cannot pass the fire spray and impact test of BS8491.

[0004] Inorganic mineral flexible fireproof cable uses fire-resistant mica tape wrapped around copper core conductor as heat-resistant insulation layer, and is filled with inorganic fiber rope (alkali-free glass fiber rope) to form a cable. The fire barrier layer uses argon arc welded copper tape corrugated copper sheath, and the outside can be extruded with smokeless and low-toxic cross-linked polyethylene sheath. Mica tape is made of mica paper, silicone adhesive, and electrician-specific unidirectional glass fiber cloth. Mica paper can be divided into white mica paper, phlogopite paper, and synthetic mica paper. White mica paper has a low temperature resistance (about 600℃), phlogopite paper has a heat resistance (about 800℃), and synthetic mica paper has a heat resistance (about 1000℃). However, since synthetic mica contains fluorine, it will be released into the environment under high temperature conditions and is prohibited in certain environments. When inorganic mineral flexible fire-resistant cables are subjected to heat, the adhesive in the mica wrapping tape decomposes due to heat, and the mica paper in the mica paper tape powders and becomes brittle. In the absence of a corrugated copper sheath fire barrier layer, the cable cannot fully pass the C, W, and Z tests of BS 6387, nor can it pass the BS 8491 test. Summary of the invention

[0005] In view of the shortcomings that the magnesium oxide powder in the insulation layer of mineral insulated cables is easy to absorb moisture and hydrolyze and deteriorate, the mica tape in inorganic mineral flexible fire-proof cables is easy to powderize when heated, and the vitrified silicone rubber insulation layer in ceramic silicone rubber flexible fire-proof cables has low vitrified shell strength when heated, high vitrification temperature, and poor thermal insulation performance, the present invention provides a composite insulation felt of basalt fiber cloth reinforced basalt fiber felt for fire-proof cables, as well as a preparation method and application thereof.

[0006] In a first aspect, the present invention provides a method for preparing a composite thermal insulation felt of basalt fiber cloth reinforced basalt fiber felt for fireproof cables, the preparation method comprising the following steps:

[0007] Pre-treating the basalt fiber to obtain a first basalt fiber;

[0008] The basalt fiber cloth is sandwiched between the two layers of the first basalt fiber laying layer, and then needle-punched, cut and rolled to obtain the basalt fiber cloth reinforced basalt fiber needle-punched felt;

[0009] The basalt fiber cloth reinforced basalt fiber needle felt is added into a hydrolyzate of a silica sol precursor and subjected to an impregnation treatment to obtain a basalt fiber cloth reinforced basalt fiber needle felt composite silica sol;

[0010] The basalt fiber cloth reinforced basalt fiber needle felt composite silica sol is subjected to aging and surface treatment, supercritical drying and cutting in sequence to obtain the composite thermal insulation felt.

[0011] Furthermore, the step of pretreating the basalt fiber to obtain the first basalt fiber includes the following process:

[0012] The basalt fiber is dried and dehumidified to obtain the first basalt fiber.

[0013] Furthermore, the steps of sandwiching the basalt fiber cloth between the two layers of the first basalt fiber laying layer, and then performing needle punching, cutting and rolling to obtain the basalt fiber cloth reinforced basalt fiber needle felt include the following processes:

[0014] The first basalt fiber is coarsely opened, finely opened and combed in sequence, and then the basalt fiber cloth is clamped between the two layers of the first basalt fiber during the laying process, and then needle-punched, cut and rolled to obtain basalt fiber cloth reinforced basalt fiber needle-punched felt.

[0015] Furthermore, the properties of the basalt fiber cloth include: fiber diameter 5-17 microns, surface density 150-500g / m 2 , the texture styles include but are not limited to plain cloth, satin cloth, twill cloth; the property parameters of the basalt fiber include: fiber diameter 5-17 microns, length 30-80mm; the property parameters of the basalt fiber cloth reinforced basalt fiber needle felt include: thickness 1.2-5.5mm, surface density 200-700g / m 2 .

[0016] Furthermore, the working condition parameters of the impregnation treatment include: the impregnation time is 30-120 seconds, and the content of the silica sol precursor hydrolyzate in the basalt fiber cloth reinforced basalt fiber needle felt composite silica sol is not less than 30wt%.

[0017] Furthermore, the aging and surface treatment steps include the following processes:

[0018] Using silane compounds to perform surface hydrophobic treatment during the aging process of the basalt fiber cloth reinforced basalt fiber needle felt composite silica sol to obtain the aged and surface treated basalt fiber cloth reinforced basalt fiber needle felt composite silica sol;

[0019] Wherein, the silane compound includes at least one of hexamethylsilane, trimethylchlorosilane, methyltriethoxysilane and methyltrimethoxysilane;

[0020] The working condition parameters of the aging and surface treatment include: an aging temperature of 25-45° C. and an aging time of 1-3 hours.

[0021] Furthermore, the supercritical drying step includes the following process:

[0022] Using water and ethanol as solvents, the aged and surface treated basalt fiber cloth reinforced basalt fiber needle felt composite silica sol is dried by carbon dioxide / ethanol supercritical drying method to obtain supercritically dried basalt fiber cloth reinforced basalt fiber needle felt composite silica sol;

[0023] The working condition parameters of the supercritical drying include: temperature of 40-85° C., drying pressure of 10-36 MPa, and the drying medium is carbon dioxide in a supercritical state.

[0024] In a second aspect, the present invention provides a composite thermal insulation felt of basalt fiber cloth reinforced basalt fiber felt for fireproof cables, wherein the composite thermal insulation felt of basalt fiber cloth reinforced basalt fiber felt for fireproof cables is prepared by the preparation method of the composite thermal insulation felt of basalt fiber cloth reinforced basalt fiber felt for fireproof cables as described in any one of the first aspects.

[0025] In a third aspect, the present invention provides the use of a composite thermal insulation felt of basalt fiber cloth reinforced basalt fiber felt for fireproof cables as described in any one of the second aspects in the preparation of fireproof cables and the preparation of thermal insulation refractory materials for fireproof cables.

[0026] In a fourth aspect, the present invention provides a fireproof cable, comprising a conductor, an insulating layer, a thermal insulation and fire-resistant layer, an inorganic filling layer, a fire barrier layer and an outer sheath; the thermal insulation and fire-resistant layer is made of a composite thermal insulation felt reinforced with basalt fiber felt by the basalt fiber cloth for fireproof cables as described in any one of the second aspects.

[0027] The above technical solution provided by the embodiment of the present invention has at least the following advantages compared with the prior art:

[0028] The embodiment of the present invention provides a composite thermal insulation felt of basalt fiber cloth reinforced basalt fiber felt for fireproof cable and a preparation method and application thereof. The fireproof cable thermal insulation composite material prepared by the present invention using basalt fiber cloth reinforced basalt fiber needle felt composited with silica aerogel has high tensile strength, moisture and water resistance, high thermal conductivity and low thermal conductivity, stable performance under high temperature conditions, no cracking, no pulverization, and as a fireproof cable thermal insulation layer material, it can effectively improve the line integrity of the fireproof cable under flame conditions and reduce the voltage drop of the cable under flame conditions. The fireproof cable is easy to process, no toxic and harmful gases are generated under heating conditions, the thermal insulation material has a small specific gravity, and the volume density is ≤500kg / m 3 , significantly lower than magnesium oxide powder (2300kg / m 3 ), mica wrapping tape (1600kg / m 3 ), ceramic silicone rubber (1560kg / m 3 ). Specifically:

[0029] 1. Compared with traditional mineral insulated fireproof cables, the prepared basalt fiber composite material is used as the fireproof cable insulation layer. The prepared fireproof cable insulation layer does not absorb moisture, has good flexibility, and has a small specific gravity. The cable production process is simple, and the high-temperature thermal insulation effect is excellent. Cables of any length can be produced, the cable has good flexibility, and the cable line voltage drop under flame conditions is small.

[0030] 2. Compared with ceramic silicone rubber flexible fireproof cable, the prepared basalt fiber composite material is used as the fireproof cable insulation layer. The prepared fireproof cable has a small specific gravity, does not produce toxic and harmful gases under fire conditions, has low organic matter content, good impact resistance, no powder falling, and cracking. The cable line voltage drop under flame conditions is small, and the cable production process is simple.

[0031] 3. Compared with inorganic mineral flexible fireproof cables, the prepared basalt fiber composite material is used as the fireproof cable insulation layer. The prepared fireproof cable does not powder or fall off under flame conditions. It is resistant to water spray and impact in the BS 6387 test, has a small specific gravity, has a small voltage drop under flame conditions, and has a low organic content. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0033] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0034] Figure 1 The present invention provides a flow chart of a method for preparing a composite thermal insulation felt of basalt fiber cloth reinforced basalt fiber felt for fireproof cables provided in an embodiment of the present invention.

[0035] Figure 2 The present invention provides an operational flow chart of a method for preparing a composite thermal insulation felt of basalt fiber cloth reinforced basalt fiber felt for fireproof cables provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0036] 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. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0037] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or prepared by existing methods.

[0038] In a first aspect, the present invention provides a method for preparing a composite thermal insulation felt of basalt fiber cloth reinforced basalt fiber felt for fireproof cables, such as Figure 1 As shown, the preparation method comprises the following steps:

[0039] Pre-treating the basalt fiber to obtain a first basalt fiber;

[0040] The basalt fiber cloth is sandwiched between the two layers of the first basalt fiber laying layer, and then needle-punched, cut and rolled to obtain the basalt fiber cloth reinforced basalt fiber needle-punched felt;

[0041] The basalt fiber cloth reinforced basalt fiber needle felt is added into a hydrolyzate of a silica sol precursor and subjected to an impregnation treatment to obtain a basalt fiber cloth reinforced basalt fiber needle felt composite silica sol;

[0042] The basalt fiber cloth reinforced basalt fiber needle felt composite silica sol is subjected to aging and surface treatment, supercritical drying and cutting in sequence to obtain the composite insulation felt.

[0043] The invention provides a method for preparing a composite thermal insulation felt of basalt fiber cloth reinforced basalt fiber felt for fireproof cables. The fireproof cable thermal insulation composite material prepared by the invention using basalt fiber cloth reinforced basalt fiber needle felt composited with silica aerogel has high tensile strength, moisture and water resistance, high thermal conductivity and low thermal conductivity, stable performance under high temperature conditions, no cracking, no pulverization, and can be used as a fireproof cable thermal insulation layer material to effectively improve the line integrity of the fireproof cable under flame conditions and reduce the voltage drop of the cable under flame conditions. The fireproof cable is easy to process, no toxic and harmful gases are generated under heating conditions, the thermal insulation material has a small specific gravity, and the volume density is ≤500kg / m 3 , significantly lower than magnesium oxide powder (2300kg / m 3 ), mica wrapping tape (1600kg / m 3 ), ceramic silicone rubber (1560kg / m 3 ). Specifically:

[0044] The present invention adopts high temperature resistant basalt fiber as a substrate to prepare a high-efficiency heat-insulating high temperature resistant basalt fiber cloth reinforced basalt fiber needle felt composite silica aerogel composite material, which is used for the flexible fireproof cable insulation layer material. The basalt fiber cloth reinforced basalt fiber needle felt has excellent high temperature resistance (softening point 860-880℃, melting point greater than 1450℃) and excellent infrared shielding ability. In the line integrity test of the fireproof cable under flame conditions (under 950±50℃ flame conditions, heat transfer is mainly infrared radiation and solid heat transfer), due to the infrared shielding ability of the basalt fiber, it can effectively limit the heat from the outside of the cable to the inside of the conductive cable. The basalt fiber cloth reinforced basalt needle felt is used as the substrate, and the sol-gel process is used to composite the high-efficiency heat-insulating high temperature resistant basalt fiber cloth reinforced basalt fiber needle felt composite silica aerogel composite material is used for the flexible fireproof cable insulation layer material. The basalt fiber cloth reinforced basalt fiber needle felt has excellent high temperature resistance (softening point 860-880℃, melting point greater than 1450℃) and excellent infrared shielding ability. In the line integrity test of the fireproof cable under flame conditions (under 950±50℃ flame conditions, heat transfer is mainly infrared radiation and solid heat transfer), the infrared shielding ability of the basalt fiber can effectively limit the heat from the outside of the cable to the inside of the conductive cable. The silica sol is synthesized, and then the supercondensation drying technology is adopted to prepare a basalt fiber cloth reinforced basalt fiber needle felt composite silica aerogel composite material. The composite material has good tensile strength after subsequent cutting. Compared with the mica wrapping tape, the subsequent adhesive bonding process is omitted. The organic matter content of the product is less than 5%, and no toxic and harmful gas will be generated under heating. The obtained product has excellent thermal insulation performance of silica material, good mechanical reinforcement ability of basalt fiber cloth reinforced basalt fiber needle felt, and subsequent gel aging surface hydrophobic modification of the product. The obtained product has low high-temperature thermal conductivity, the thermal conductivity at 500°C is ≤0.06W / m·K, the thermal conductivity at 800 degrees Celsius is ≤0.1W / m·K, the water contact angle on the material surface is ≥120°, and it does not absorb moisture.

[0045] The flexible fireproof cable prepared by using the product of the invention as the heat insulation material of the fireproof cable, the mica wrapping tape as the insulation layer, and the argon arc welding copper tape corrugated sheath as the fire barrier layer can pass the C, W, Z grade test in BS 6387 and the BS8491 test, simplifying the production process of the fireproof cable (because the basalt fiber cloth is used as the mechanical reinforcement layer of the material, the mica tape wrapping process can be used to wrap the conductor cable, and the cable manufacturer does not need to upgrade the existing equipment) and improve the safety of the cable. According to the C fire resistance test of 6387, there is no falling, powdering or cracking inside the cable, the insulation layer structure is intact, and there is no mica flake shedding or powdering in the internal mica wrapping tape insulation layer. During the temperature rise process of ordinary fireproof cables due to the rapid increase in the temperature of the internal copper wire, the cable resistance rises rapidly, and the voltage drop of the equipment increases accordingly. When it reaches a certain level (about 10%), the equipment cannot work normally due to the excessive voltage drop of the rated voltage. In view of the excellent high-temperature thermal insulation performance of the insulation layer of the present invention, during the fire process of the cable, the temperature of the internal conductor rises slowly, and the voltage drop at the two ends of the cable is low, which can maintain the normal operation of important fire-fighting equipment when a fire occurs, thereby improving the safety of the fireproof cable.

[0046] In some specific embodiments, the preparation method of the silica sol precursor hydrolyzate includes: selecting orthosilicate and a hydrolyzing agent, mixing, adjusting the pH, and obtaining an aerogel precursor hydrolyzate; the hydrolyzing agent includes deionized water and anhydrous ethanol; the mass ratio of the deionized water and anhydrous ethanol is 10-50:30-85; the mass ratio of the orthosilicate and the hydrolyzing agent is 520:40-125. Specifically, it can be: select 50 grams of orthosilicate and a hydrolyzing agent (100 grams of deionized water and 300 grams of anhydrous ethanol) according to the proportion, mix, first add hydrochloric acid solution to adjust the pH value to 3-5, stir for the first time for 15 minutes, then add ammonia water to adjust the pH value to 7-8, and stir for the second time for 15 minutes.

[0047] In some specific embodiments, Figure 2 As shown, the preparation method of the composite thermal insulation felt of basalt fiber cloth reinforced basalt fiber felt for fireproof cable provided by the present invention includes the following operation process and principle:

[0048] The present invention adopts basalt fiber cloth as the reinforcement of basalt fiber needle felt. In the process of basalt fiber needle felt production and laying, the basalt fiber cloth is clamped between two layers of basalt fiber laying layers, and then the basalt fiber cloth is reinforced by needle cutting of the equipment to prepare the basalt fiber needle felt product. Due to the addition of basalt fiber cloth, compared with ordinary basalt fiber needle felt, it has good mechanical strength, and the longitudinal tensile strength is greater than 100N / cm, which is much higher than the tensile strength of mica wrapping tape, and can meet the tension requirement of the wrapping machine in the subsequent cable wrapping process. The fiber diameter of the basalt fiber cloth used is 5-17 microns, and the surface density is 150-500g / m 2 , including but not limited to plain weave, satin weave, twill weave. The fiber diameter of basalt needle felt is 5-17 microns, the length is 30-80mm, the thickness of basalt fiber cloth reinforced basalt fiber needle felt products is 1.2-5.5mm, and the surface density is 200-700g / m 2 .

[0049] The prepared basalt fiber cloth reinforced basalt fiber needle felt was used as the substrate, and the basalt fiber cloth reinforced basalt fiber needle felt silica composite material was prepared by sol-gel, aging, surface treatment, and supercritical drying technology. Then, the cutting and winding equipment was used to finally prepare the fireproof cable insulation layer wrapping material. The silica sol-gel process uses ethyl orthosilicate as the silicon source, glacial acetic acid as the ethyl orthosilicate hydrolysis catalyst, trimethylchlorosilane as the aged surface hydrophobic treatment surface modifier, water and ethanol as solvents, and the carbon dioxide / ethanol supercritical drying technology is used to dry the gel product. The prepared fireproof cable heat-insulating wrapping material has high tensile strength, with a tensile strength greater than 100N / cm; a hydrophobic surface that does not absorb moisture, with a water contact angle greater than 120°; a low thermal conductivity, with the thermal conductivity at room temperature of 25°C being ≤0.024W / m·K, the thermal conductivity at 300°C being ≤0.04W / m·K, the thermal conductivity at 500°C being ≤0.06W / m·K, and the thermal conductivity at 800°C being ≤0.1W / m·K; an organic matter content being ≤5%, and no toxic or harmful gas being released when heated; and excellent temperature resistance, with a short-term maximum heat resistance temperature of up to 1100°C.

[0050] The middle reinforcement layer is made of glass fiber cloth. After the final product is subjected to the Class C fire resistance test of BS6387, the internal insulation composite material has a low softening point of glass fiber (450-600℃). After being heated at 1000℃ for 2h, the strength of the glass fiber cloth decreases significantly and no longer has structural strength. The insulation layer is easily detached under impact and cannot meet the impact test in BS6387. Basalt fiber cloth is used alone as the insulation layer of the fireproof cable. Due to the high test flame of 1000℃, the strength of the basalt fiber cloth decreases after heating. It is powdered and falls off under impact conditions and cannot meet the impact test in BS6387. At the same time, due to the denseness of basalt fiber cloth products and the high thermal conductivity under high temperature conditions, the internal temperature of the fireproof cable increases under flame conditions, and the resistivity of the insulation layer decreases, which eventually leads to electrode breakdown of the fireproof cable after 30-60min of fire, which cannot meet the line integrity test of the fireproof cable under flame conditions (Class C test in BS6387). The basalt fiber needle felt with a fiber diameter of 13 microns, 11 microns, and 9 microns is used as the raw material for the preparation of basalt fiber cloth reinforced basalt fiber needle felt, and its thickness is relatively large. The basalt fiber with a diameter of 13 microns is used to produce basalt fiber cloth reinforced basalt fiber needle felt with a thickness of 6.5-7.5mm, the basalt fiber with a diameter of 11 microns is used to produce basalt fiber cloth reinforced basalt fiber needle felt with a thickness of 5.5-6.5mm, the basalt fiber with a diameter of 9 microns is used to produce basalt fiber cloth reinforced basalt fiber needle felt with a thickness of 4.5-5.5mm, and the basalt fiber with a diameter of 7 microns is used to produce basalt fiber cloth reinforced basalt fiber needle felt with a thickness of 1.5-3.5mm. Due to the large thickness of basalt needle felt reinforced by basalt fiber cloth, the subsequent thickness of silica aerogel composite felt is too thick, and the overlap of the insulation layer during the wrapping process of the fireproof cable insulation layer is incomplete at the overlap, and the overlap height is too large to show a corrugated convex shape. Due to the incomplete overlap of the insulation layer, it is easy to cause the insulation to fail under flame conditions, and ultimately cause the cable line integrity to fail under flame conditions. The corrugated convex insulation layer causes the copper sheath size to increase, the material consumption increases, and the cable weight increases. Basalt fiber cloth is made of plain, twill, and satin cloth, with a surface density of 150-350g / m 2 , of which the surface density is 150g / m 2 The basalt fiber cloth is used as the reinforcement layer. The tensile strength of the prepared basalt fiber needle-punched composite felt is low, and the wrapping tape breaks during the wrapping of the fireproof cable insulation layer. 2 The basalt fiber cloth can achieve good mechanical strength of the fireproof cable insulation layer while maintaining a low thickness of the insulation layer. The surface density is 260-250g / m 2In the process of producing basalt fiber needle felt, basalt fiber cloth is used as the reinforcing layer material. Due to the high density of basalt fiber cloth, the needles of the needle punching machine cannot effectively pierce the basalt fiber cloth. The surface of the prepared basalt fiber cloth reinforced basalt fiber needle felt has many burrs and poor flatness.

[0051] The surface hydrophobicity of basalt fiber cloth reinforced basalt fiber needle punched felt composite silica aerogel composite material is treated. During the aging process, hexamethyl silane, trimethyl chlorosilane, methyl triethoxy silane, methyl trimethoxy silane and the like are used for surface hydrophobic treatment. The surface water contact angle of basalt fiber cloth reinforced basalt fiber composite silica aerogel felt after hexamethyl silane hydrophobic treatment is 140°-147°, the surface water contact angle of basalt fiber cloth reinforced basalt fiber composite silica aerogel felt treated with trimethyl chlorosilane as a hydrophobic treatment agent is 130°-138°, and the surface water contact angle of basalt fiber cloth reinforced basalt fiber composite silica aerogel felt treated with methyl triethoxy silane / methyl trimethoxy silane as a hydrophobic treatment agent is 120°-128°.

[0052] In a second aspect, the present invention provides a composite thermal insulation felt of basalt fiber cloth reinforced basalt fiber felt for fireproof cables, wherein the composite thermal insulation felt of basalt fiber cloth reinforced basalt fiber felt for fireproof cables is prepared by the preparation method of the composite thermal insulation felt of basalt fiber cloth reinforced basalt fiber felt for fireproof cables as described in any one of the first aspects.

[0053] In a third aspect, the present invention provides the use of a composite thermal insulation felt of basalt fiber cloth reinforced basalt fiber felt for fireproof cables as described in any one of the second aspects in the preparation of fireproof cables and the preparation of thermal insulation refractory materials for fireproof cables.

[0054] In a fourth aspect, the present invention provides a fireproof cable, comprising a conductor, an insulating layer, a thermal insulation and fire-resistant layer, an inorganic filling layer, a fire barrier layer and an outer sheath; the thermal insulation and fire-resistant layer is made of a composite thermal insulation felt reinforced with basalt fiber felt by the basalt fiber cloth for fireproof cables as described in any one of the second aspects.

[0055] It should be noted that the composite thermal insulation felt of basalt fiber cloth reinforced basalt fiber felt for fireproof cable provided by the embodiment of the present invention and the component raw materials involved in the preparation method and application thereof can directly adopt commercial products unless otherwise specified or specified. At the same time, the operation steps involved, if not specifically specified, such as preparing the composite thermal insulation felt of basalt fiber cloth reinforced basalt fiber felt for fireproof cable reinforced basalt fiber cloth reinforced basalt fiber felt, can refer to the existing technology such as patent number CN 113860850 A or use existing equipment.

[0056] The present invention will be further described below in conjunction with specific examples. It should be understood that these examples are intended only to illustrate the present invention and are not intended to limit the scope of the present invention. The experimental methods in the following examples that do not specify specific conditions are usually measured according to national standards. If there is no corresponding national standard, then the conditions recommended by the manufacturer are followed.

[0057] Example 1

[0058] This example provides a composite thermal insulation felt of basalt fiber cloth reinforced basalt fiber felt for fireproof cables, and the preparation method thereof comprises the following steps:

[0059] Step 1: Fiber diameter is 5 microns and surface density is 150g / m 2 , basalt fiber plain cloth, and basalt fiber chopped yarn with a diameter of 7 microns to prepare basalt fiber cloth reinforced felt, with a thickness of 1.5-2mm and a surface density of 200g / m 2 ;

[0060] Step 2: The basalt fiber cloth reinforced felt described in step 1 is compounded with silica sol using the technology described in Example 1 of "Patent No. CN 113860850 A is a composite insulation mat and its production process" to prepare a composite insulation felt of basalt fiber cloth reinforced basalt fiber felt for fireproof cables, specifically including: 2.1, preparing aerogel precursor hydrolyzate: select 50 grams of orthosilicate and hydrolyzing agent (100 grams of deionized water and 300 grams of anhydrous ethanol) in proportion, mix them, first add hydrochloric acid solution to adjust the pH value to 3-5, stir for the first time for 15 minutes, then add ammonia water to adjust the pH value to 7-8, stir for the second time for 15 minutes, and obtain aerogel precursor hydrolyzate; 2.2, impregnation substrate: place The winding machine places a 1mm thick basalt fiber needle felt substrate in an aerogel precursor hydrolyzate and immerses it for 30 seconds. Then, the basalt fiber needle felt substrate impregnated with the aerogel precursor hydrolyzate is squeezed and rolled up by a winder to obtain a sol-like basalt fiber needle felt, in which the content of aerogel precursor hydrolyzate in the sol-like basalt fiber needle felt is not less than 30%, and the diameter of the felt roll is not more than 0.5m; 2.3. Obtaining the finished product: The sol-like basalt fiber needle felt is aged at 25 degrees Celsius for 1 hour, microwave dried, and supercritically dried at 40 degrees Celsius and 10MPa for 1 hour to obtain the finished product.

[0061] Example 2

[0062] This example provides a composite thermal insulation felt of basalt fiber cloth reinforced basalt fiber felt for fireproof cables, and the preparation method thereof comprises the following steps:

[0063] Step 1: Fiber diameter is 7 microns and surface density is 200g / m 2The basalt fiber plain cloth is made of basalt fiber chopped yarn with a diameter of 7 microns to prepare basalt fiber cloth reinforced felt with a thickness of 2-3.5mm and a surface density of 250g / m 2 ;

[0064] Step 2: Compound the basalt fiber cloth reinforced felt described in step 1 with silica sol using the technology described in Example 1 of "Patent No. CN 113860850 A is a composite thermal insulation mat and its production process" to prepare a composite thermal insulation felt of basalt fiber cloth reinforced basalt fiber felt for fireproof cables.

[0065] Example 3

[0066] This example provides a composite thermal insulation felt of basalt fiber cloth reinforced basalt fiber felt for fireproof cables, and the preparation method thereof comprises the following steps:

[0067] Step 1: Fiber diameter is 9 microns and surface density is 300g / m 2 , basalt fiber twill fabric, and basalt fiber chopped yarn with a diameter of 9 microns to prepare basalt fiber cloth reinforced felt, with a thickness of 4.5-5.5mm and a surface density of 450g / m 2 .

[0068] Step 2: Compound the basalt fiber cloth reinforced felt described in step 1 with silica sol using the technology described in Example 1 of "Patent No. CN 113860850 A is a composite thermal insulation mat and its production process" to prepare a composite thermal insulation felt of basalt fiber cloth reinforced basalt fiber felt for fireproof cables.

[0069] Example 4

[0070] This example provides a composite thermal insulation felt of basalt fiber cloth reinforced basalt fiber felt for fireproof cables, and the preparation method thereof comprises the following steps:

[0071] Step 1: Basalt fiber satin cloth with a fiber diameter of 11 microns and a surface density of 450g / m2 is used to prepare basalt fiber cloth reinforced felt with a thickness of 5.5-6.5mm and a surface density of 650g / m2. 2 .

[0072] Step 2: Compound the basalt fiber cloth reinforced felt described in step 1 with silica sol using the technology described in Example 1 of "Patent No. CN 113860850 A is a composite thermal insulation mat and its production process" to prepare a composite thermal insulation felt of basalt fiber cloth reinforced basalt fiber felt for fireproof cables.

[0073] Example 5

[0074] This example provides a composite thermal insulation felt of basalt fiber cloth reinforced basalt fiber felt for fireproof cables, and the preparation method thereof comprises the following steps:

[0075] Step 1: Fiber diameter is 13 microns and surface density is 450g / m 2 , basalt fiber satin cloth, and basalt fiber chopped yarn with a diameter of 13 microns to prepare basalt fiber cloth reinforced felt, with a thickness of 6.5-7.5mm and a surface density of 700g / m 2 .

[0076] Step 2: Compound the basalt fiber cloth reinforced felt described in step 1 with silica sol using the technology described in Example 1 of "Patent No. CN 113860850 A is a composite thermal insulation mat and its production process" to prepare a composite thermal insulation felt of basalt fiber cloth reinforced basalt fiber felt for fireproof cables.

[0077] Comparative Example 1:

[0078] The only difference between this example and Example 1 is that 9-micron basalt fiber twill cloth is directly used as the flame-retardant and heat-insulating material for cables; the fiber cloth surface density is 300 g / m2 and the thickness is 0.3 mm.

[0079] Comparative Example 2

[0080] The only difference between this example and Example 1 is that 9-micron basalt fiber needle felt is used directly as the flame-retardant heat-insulating material for cables; the needle felt has a surface density of 150 g / m2 and a thickness of 2.5 mm.

[0081] Comparative Example 3

[0082] This example differs from Example 1 only in that:

[0083] Step 1: Fiber diameter is 7 microns and surface density is 200g / m 2 , glass fiber plain cloth, and glass fiber chopped yarn with a diameter of 7 microns to prepare glass fiber cloth reinforcement mat, with a thickness of 2-3.5mm and a surface density of 250g / m 2 ;

[0084] Step 2: The glass fiber cloth reinforced felt described in step 1 is compounded with silica sol using the technology described in Example 1 of "Patent No. CN 113860850 A is a composite thermal insulation mat and its production process" to prepare a composite thermal insulation felt of basalt fiber cloth reinforced basalt fiber felt for fireproof cables.

[0085] Comparative analysis:

[0086] Comparative Example 2 is compared with Implementation 2: Implementation 2 uses basalt fiber cloth as the reinforcement of basalt fiber needle felt. During the production and laying process of basalt fiber needle felt, the basalt fiber cloth is clamped between the two layers of basalt fiber laying layers. Subsequently, the basalt fiber cloth-reinforced basalt fiber needle felt product is prepared by needle-punching and cutting of the equipment. Due to the addition of basalt fiber cloth, compared with ordinary basalt fiber needle felt, it has good mechanical strength, and the longitudinal tensile strength is greater than 100N / cm, which is much higher than the tensile strength of mica wrapping tape, and can meet the tension requirements of the wrapping machine in the subsequent cable wrapping process. The thermal conductivity is low, the thermal conductivity at room temperature of 25℃ is ≤0.024W / m·K, the thermal conductivity at 300℃ is ≤0.04W / m·K, the thermal conductivity at 500℃ is ≤0.06W / m·K, and the thermal conductivity at 800℃ is ≤0.1W / m·K; the organic content is ≤5%, and no toxic or harmful gas is released when heated; the temperature resistance is excellent, and the short-term maximum heat resistance temperature can reach 1100℃.

[0087] Comparative Example 1 is compared with Example 2:

[0088] Basalt fiber cloth is used alone as the thermal insulation layer of fireproof cable. Due to the test flame as high as 1000℃, the strength of basalt fiber cloth decreases after heating, and it powders and falls off under impact conditions, which cannot meet the impact test in BS6387 test. At the same time, due to the density of basalt fiber cloth products and high thermal conductivity under high temperature conditions, the internal temperature of the fireproof cable increases under flame conditions, and the resistivity of the insulation layer decreases, which eventually leads to electrode breakdown of the fireproof cable after 30-60 minutes of fire, which cannot meet the line integrity test of the fireproof cable under flame conditions (Class C test in BS6387).

[0089] Comparative Example 3 is compared with Example 2:

[0090] The middle reinforcement layer is made of glass fiber cloth. After the final product is subjected to the Class C fire resistance test of the BS6387 test, the internal insulation composite material has a significant decrease in strength due to the low softening point of glass fiber (450-600℃). After being heated at 1000℃ flame for 2 hours, the glass fiber cloth no longer has structural strength. The insulation layer is easily detached when impacted, and cannot meet the impact test in the BS6387 test.

[0091] Implement column 1, 2, 3, 4, 5 analysis

[0092] The basalt fiber needle felt with a fiber diameter of 13 microns, 11 microns, and 9 microns is used as the raw material for the needle felt to prepare the basalt fiber cloth reinforced basalt fiber needle felt, and the thickness is relatively large. The basalt fiber cloth reinforced basalt fiber needle felt produced by the basalt fiber with a diameter of 13 microns has a thickness of 6.5-7.5mm. Due to the excessive density of the basalt fiber cloth, the needles of the needle punching machine cannot effectively pierce the basalt fiber cloth. The prepared basalt fiber cloth reinforced basalt fiber needle felt has more burrs on the surface and poor flatness. The thickness of basalt fiber cloth reinforced basalt fiber needle felt produced by basalt fiber with a diameter of 11 microns is 5.5-6.5mm, and the thickness of basalt fiber cloth reinforced basalt fiber needle felt produced by basalt fiber with a diameter of 9 microns is 4.5-5.5mm. Since the thickness of basalt fiber cloth reinforced basalt needle felt is too large, and the thickness of the subsequent composite silica aerogel composite felt is too thick, the overlap of the insulation layer during the wrapping process of the fireproof cable insulation layer, the insulation layer with a relatively large thickness is incomplete at the overlap, and the height of the overlap is relatively large and presents a corrugated convex shape. Due to the incomplete overlap of the insulation layer, it is easy to cause the insulation failure under flame conditions, and ultimately lead to the failure of the cable line integrity under flame conditions. The corrugated and convex insulation layer causes the copper sheath size to become larger, the material consumption increases, and the cable weight increases.

[0093] The thickness of basalt fiber needle felt reinforced with basalt fiber cloth produced by 5 micron basalt fiber is 1.5-3.5mm. The basalt fiber cloth adopts plain, twill and satin cloth with a surface density of 150-350g / m2. The basalt fiber cloth with a surface density of 150g / m2 is used as the reinforcement layer. The tensile strength of the prepared basalt fiber needle composite felt is low, and the wrapping tape breaks in the wrapping of the fireproof cable insulation layer.

[0094] The basalt fiber cloth reinforced with 7-micron basalt fiber is produced. The basalt fiber cloth with a surface density of 250g / m2 can achieve good mechanical strength of the fireproof cable insulation layer while maintaining a low thickness of the insulation layer.

[0095] Various embodiments of the present invention may be presented in the form of a range; it should be understood that the description in the form of a range is only for convenience and brevity, and should not be understood as a rigid limitation on the scope of the present invention; therefore, the range description should be considered to have specifically disclosed all possible sub-ranges and single numerical values ​​within the range. For example, the range description from 1 to 6 should be considered to have specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as single numbers within the range, such as 1, 2, 3, 4, 5 and 6, which apply regardless of the range. In addition, whenever a numerical range is indicated herein, it is meant to include any cited number (fractional or integer) within the indicated range.

[0096] In the description of the specification of the present invention, the terms "including", "comprising", etc. mean "including but not limited to". In this article, relational terms such as "first" and "second", etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. In this article, "and / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. Wherein A and B can be singular or plural. In this article, "at least one" means one or more, and "plurality" means two or more. "At least one", "at least one of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, "at least one of a, b, or c", or "at least one of a, b, and c", can both mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, c can be single or plural, respectively.

[0097] The foregoing is merely a specific embodiment of the present invention, which enables those skilled in the art to understand or implement the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A method for preparing a composite thermal insulation felt of basalt fiber cloth reinforced basalt fiber felt for fireproof cables, characterized in that: The preparation method comprises the following steps: Pre-treating the basalt fiber to obtain a first basalt fiber; The basalt fiber cloth is sandwiched between the two layers of the first basalt fiber laying layer, and then needle-punched, cut and rolled to obtain the basalt fiber cloth reinforced basalt fiber needle-punched felt; The basalt fiber cloth reinforced basalt fiber needle felt is added into a hydrolyzate of a silica sol precursor and subjected to an impregnation treatment to obtain a basalt fiber cloth reinforced basalt fiber needle felt composite silica sol; The basalt fiber cloth reinforced basalt fiber needle felt composite silica sol is subjected to aging and surface treatment, supercritical drying and cutting in sequence to obtain the composite insulation felt.

2. The method for preparing the composite thermal insulation felt of basalt fiber cloth reinforced basalt fiber felt for fireproof cable according to claim 1, characterized in that: The step of pre-treating the basalt fiber to obtain the first basalt fiber includes the following process: The basalt fiber is dried and dehumidified to obtain the first basalt fiber.

3. The method for preparing the composite thermal insulation felt of basalt fiber cloth reinforced basalt fiber felt for fireproof cable according to claim 2, characterized in that: The steps of sandwiching the basalt fiber cloth between the two layers of the first basalt fiber laying layer, and then needle punching, cutting and rolling to obtain the basalt fiber cloth reinforced basalt fiber needle felt include the following processes: The first basalt fiber is coarsely opened, finely opened and combed in sequence, and then the basalt fiber cloth is clamped between the two layers of the first basalt fiber during the laying process, and then needle-punched, cut and rolled to obtain basalt fiber cloth reinforced basalt fiber needle-punched felt.

4. The method for preparing the composite thermal insulation felt of basalt fiber cloth reinforced basalt fiber felt for fireproof cable according to claim 1, characterized in that: The properties of the basalt fiber cloth include: fiber diameter 5-17 microns, surface density 150-500g / m 2 , the texture styles include but are not limited to plain cloth, satin cloth, twill cloth; the property parameters of the basalt fiber include: fiber diameter 5-17 microns, length 30-80mm; the property parameters of the basalt fiber cloth reinforced basalt fiber needle felt include: thickness 1.2-5.5mm, surface density 200-700g / m 2 .

5. The method for preparing the composite thermal insulation felt of basalt fiber cloth reinforced basalt fiber felt for fireproof cable according to claim 1, characterized in that: The working condition parameters of the impregnation treatment include: the impregnation time is 30-120 seconds, and the content of the silica sol precursor hydrolyzate in the basalt fiber cloth reinforced basalt fiber needle felt composite silica sol is not less than 30wt%.

6. The method for preparing the composite thermal insulation felt of basalt fiber cloth reinforced basalt fiber felt for fireproof cable according to claim 1, characterized in that: The aging and surface treatment steps include the following processes: Using silane compounds to perform surface hydrophobic treatment during the aging process of the basalt fiber cloth reinforced basalt fiber needle felt composite silica sol to obtain the aged and surface treated basalt fiber cloth reinforced basalt fiber needle felt composite silica sol; Wherein, the silane compound includes at least one of hexamethylsilane, trimethylchlorosilane, methyltriethoxysilane and methyltrimethoxysilane; The working condition parameters of the aging and surface treatment include: an aging temperature of 25-45° C. and an aging time of 1-3 hours.

7. The method for preparing the composite thermal insulation felt of basalt fiber cloth reinforced basalt fiber felt for fireproof cable according to claim 6, characterized in that: The supercritical drying step includes the following process: Using water and ethanol as solvents, the aged and surface treated basalt fiber cloth reinforced basalt fiber needle felt composite silica sol is dried by carbon dioxide / ethanol supercritical drying method to obtain supercritically dried basalt fiber cloth reinforced basalt fiber needle felt composite silica sol; The working condition parameters of the supercritical drying include: temperature of 40-85° C., drying pressure of 10-36 MPa, and the drying medium is carbon dioxide in a supercritical state.

8. A composite thermal insulation felt of basalt fiber cloth reinforced basalt fiber felt for fireproof cable, characterized in that: The composite thermal insulation felt of basalt fiber cloth reinforced basalt fiber felt for fireproof cable is prepared by the preparation method of the composite thermal insulation felt of basalt fiber cloth reinforced basalt fiber felt for fireproof cable according to any one of claims 1 to 7.

9. Use of the composite thermal insulation felt of the basalt fiber cloth reinforced basalt fiber felt for fireproof cables according to claim 8 in the preparation of fireproof cables and the preparation of thermal insulation refractory materials for fireproof cables.

10. A fireproof cable, characterized in that: The fireproof cable comprises a conductor, an insulating layer, a heat-insulating fire-resistant layer, an inorganic filling layer, a fire-blocking layer and an outer sheath; the heat-insulating fire-resistant layer is made of a composite heat-insulating felt of basalt fiber cloth reinforced with basalt fiber felt for fireproof cables as claimed in claim 8.

Images