Process for the preparation of a flexible refractory cable core wrap based on alumina fibers

Abstract

The application discloses a preparation process of an alumina fiber-based flexible fire-resistant cable core wrapping tape, and comprises the following steps: dissolving polyethylene oxide to prepare a solution for standby; dispersing aramid pulp fibers, aramid fibrid fibers, alumina fibers and the polyethylene oxide solution in water to obtain a mixed suspension A; filtering the mixed suspension A through a screen and then performing hot-press drying to form a fiber composite paper; and performing hot-press finishing on the obtained fiber composite paper to obtain the cable core wrapping tape. The cable core wrapping tape prepared through the process has the characteristics of flexibility, fire resistance, flame resistance, non-hygroscopicity and the like, is suitable for special cable manufacturing under high-temperature working conditions, and has the advantages of simple process, environmental protection, controllable cost and the like.

Description

TECHNICAL FIELD

[0001] The application relates to a preparation process of an alumina fiber-based flexible fireproof cable core wrapping tape, and belongs to the technical field of special cable manufacturing. BACKGROUND

[0002] The fireproof cable core wrapping tape can keep the insulation stability of the cable in the presence of open flames, and is a key layer for manufacturing special cables, especially fireproof wire cables. At present, in the field of fireproof core wrapping tapes, domestic products have uneven performance and great formula differences. Although the high-flame-retardant wrapping tapes of the American DuPont Company and the Japanese Toray have excellent performance, the flexibility, aging resistance and fire resistance of the wrapping tapes prepared from silica gel, mica and PET are not outstanding. Meanwhile, most of the existing core wrapping tapes on the market have some problems in the preparation process, such as the need to apply flame retardants and fire retardants, and these substances usually contain halogens. Although the flame-retardant effect is good, secondary pollution gas and smoke will be released in the combustion process. In addition, silica gel is used as the adhesive component, which inevitably uses toluene as a diluent, endangering the life health and environmental safety of the manufacturing process. Therefore, there is no flexible fireproof cable core wrapping tape that can meet the requirements of the rapid development of cables for the manufacture of special cables in the fields of high-speed trains, nuclear power and hydropower at home and abroad. SUMMARY

[0003] The application aims to provide a preparation process of an alumina fiber-based flexible fireproof cable core wrapping tape. The cable core wrapping tape prepared by the process has the characteristics of flexibility, fire resistance, flame retardation and non-hygroscopicity, is suitable for the manufacture of special cables under high-temperature working conditions, and has the advantages of simple process, environmental protection, controllable cost and the like.

[0004] The technical scheme adopted by the application is as follows:

[0005] A preparation process of an alumina fiber-based flexible fireproof cable core wrapping tape, comprising the following steps:

[0006] S1: dissolving and configuring polyethylene oxide into a solution for standby use;

[0007] S2: defibrating and dispersing aramid pulp fibers, aramid fibrid fibers, alumina fibers and the polyethylene oxide solution in water to obtain a mixed suspension A;

[0008] S3: filtering the mixed suspension A on a screen and then hot-pressing and drying to form a fiber composite paper;

[0009] S4: hot-pressing and finishing the obtained fiber composite paper to obtain the cable core wrapping tape.

[0010] Preferably, the polyethylene oxide has a molecular weight of greater than or equal to 100000; and the polyethylene oxide solution has a concentration of 3-10 g / L.

[0011] Preferably, the mass ratio of the aramid pulp fiber, aramid fiber, aluminum oxide fiber and polyethylene oxide solution is (45-55):(25-35):(15-20):(1-6).

[0012] Preferably, the aramid pulp fiber is para-aramid fiber; and the aramid fiber is meta-aramid fiber.

[0013] Preferably, the specific surface area of the aramid fiber is greater than or equal to 6 m 2 / g.

[0014] Preferably, the aluminum oxide fiber comprises fiber segments with lengths of 3mm, 5mm and 7mm, and the mass ratio of the fiber segments with lengths of 3mm, 5mm and 7mm is (25-35):(45-55):(15-25).

[0015] Preferably, the concentration of the mixed suspension A is (2-3)g / L.

[0016] Preferably, in the online filtration, the mesh number is 600-700 meshes; and the gram weight of the fiber composite paper is 60-70g / m 2 .

[0017] Preferably, the hot-pressing drying temperature is 95-110 DEG C, the time is 15-20min, and the pressure is 5-10MPa.

[0018] Preferably, the hot-pressing finishing temperature is 220-250 DEG C, the time is 5-8min, and the pressure is 10-15MPa.

[0019] The present application has the advantages that:

[0020] The preparation process of the cable core wrapping material provided by the present application ensures the rapid forming of the aluminum oxide fiber, and has the production advantages of green environmental protection, low noise, no chemical reagent release and the like in the process.

[0021] Firstly, in view of the problems of low temperature resistance grade, poor fire resistance and halogen release of the traditional aramid fiber, aramid mica tape and PET-based mica tape cable core wrapping, the present application preferably uses aluminum oxide fiber as the core material, and realizes thinning through the auxiliary forming of aramid fiber and aramid pulp fiber, so as to be used for cable core wrapping and expand the function of aluminum oxide fiber.

[0022] Secondly, the reagents used in the process of the present application are all conventional materials, which are non-toxic, low in price and easy to obtain, and the equipment used is conventional wet forming equipment, which lays a foundation for the marketization of the technical product protected by the present application, controls the manufacturing cost and improves the commodity competitiveness.

[0023] Further, in the manufacturing process of the application, the drying temperature is shortened to the maximum extent on the basis of energy saving and consumption reduction, the thermal bonding process (thermal pressing finishing) can avoid the high-temperature panniculitis of aramid fiber and enhance the bonding, and the aramid pulp fiber can assist in forming a reticular structure to avoid the shedding of aluminum oxide fiber.

[0024] Further, compared with the traditional core wrapping tape, the application preferably uses superfine aluminum oxide fiber as the core material, which has high temperature resistance (above 1000 DEG C), is non-combustible and does not smoke, and the application preferably uses aramid pulp and aramid sediment as auxiliary forming fibers, which have self-extinguishing properties, thereby improving the fire resistance, and the three basic raw fibers have certain flexibility, so that the prepared material also has this property, and the prepared cable core wrapping tape has good flexibility and is convenient for cable processing and manufacturing.

[0025] Further, the application preferably uses commercial aluminum oxide fiber as a fire-resistant and flame-retardant component, which can achieve efficient fire resistance and flame retardance through three mechanisms: (1) the aluminum oxide fiber itself does not have a combustible component, and the aluminum oxide itself is an oxide and does not have the possibility of further combustion, which essentially eliminates combustion and even acts as a fire barrier material; (2) the aluminum oxide fiber accounts for about 50% in the core wrapping tape, which isolates the aramid fiber and avoids heat accumulation in the aramid fiber to cause carbonization; (3) the aluminum oxide fiber itself has good thermal conductivity, which avoids heat accumulation.

[0026] Further, the application adopts a different length aluminum oxide fiber matching strategy, which avoids problems such as uneven dispersion of long fibers in water and weak strength of the core wrapping tape caused by too many short fibers, and lays a foundation for manufacturing high-quality cable core wrapping tapes.

[0027] Finally, the application preferably uses a wet forming method to prepare the aluminum oxide fiber core wrapping tape, which realizes the compounding of fiber types compared with weaving, avoids the cumbersome process of secondary insulation treatment of the fabric, and the disordered interweaving of the fibers avoids the risk of disintegration caused by the fracture of weak stress points, thereby improving the reliability of processing and manufacturing. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 The figure is a process flow chart of the application.

[0029] Figure 2 The figure is a SEM image of the cable core wrapping tape obtained in Example 2. DETAILED DESCRIPTION

[0030] The application will be specifically described below in combination with the drawings and examples.

[0031] The application discloses a preparation process of an aluminum oxide fiber-based flexible fire-resistant cable core wrapping tape material, which comprises the following steps: Figure 1As shown, comprising the following steps:

[0032] S1: The alumina fiber with a diameter of 5 microns is cut into lengths of 3 mm, 5 mm, and 7 mm, and is matched in a mass ratio of 3 mm:5 mm:7 mm at 30%:50%:20%;

[0033] S2: The polyethylene oxide with a molecular weight of 100000 is dissolved in water to prepare a 5g / L solution for standby;

[0034] S3: The alumina fiber, aramid pulp fiber, aramid fiber, and polyethylene oxide solution are added in a ratio of 50wt%, 30wt%, 17wt%, and 3wt% respectively, and are dispersed at 20000 rpm in tap water to obtain a mixed suspension system A with a fiber slurry content of 2g / L;

[0035] S4: The mixed suspension system A is vacuum-assisted filtered and dewatered on a 600 mesh filter screen, and then is hot-pressed and dried at 95°C and 8MPa pressure for 15min to form an alumina fiber / aramid fiber composite paper with a basis weight of 60g / m 2 ;

[0036] S5: The obtained alumina fiber / aramid pulp fiber composite paper is hot-pressed and finished at 220°C and 8MPa pressure for 5min to obtain an alumina fiber-based flexible fire-resistant cable core wrapping tape.

[0037] Example 1

[0038] The embodiment discloses a preparation process of an alumina fiber-based flexible fire-resistant cable core wrapping tape material, comprising the following steps:

[0039] S1: The alumina fiber with a diameter of 8 microns is cut into lengths of 3 mm, 5 mm, and 7 mm, and is matched in a mass ratio of 3 mm:5 mm:7 mm at 30%:50%:20%;

[0040] S2: The polyethylene oxide with a molecular weight of 100000 is dissolved to prepare a 5g / L solution for standby;

[0041] S3: The alumina fiber, aramid pulp fiber, aramid fiber, and polyethylene oxide solution are added in a ratio of 50wt%, 30wt%, 17wt%, and 3wt% respectively, and are dispersed at 20000 rpm in tap water to obtain a mixed suspension system A with a fiber slurry content of 2.5g / L;

[0042] S4: The mixed suspension system A is vacuum-assisted filtered and dewatered on a 600-900 mesh filter screen, and then is hot-pressed and dried at 100°C and 8MPa pressure for 18min to form an alumina fiber / aramid fiber composite paper with a basis weight of 65g / m 2 ;

[0043] S5: The obtained alumina fiber / aramid pulp fiber composite paper is hot-pressed at a high temperature of 230°C and a pressure of 9MPa for 7min to obtain an alumina fiber-based flexible fire-resistant cable core wrapping tape.

[0044] Example 2

[0045] The present embodiment discloses a preparation process of an alumina fiber-based flexible fire-resistant cable core wrapping tape material, comprising the following steps:

[0046] S1: The alumina fibers with a diameter of 12 microns are cut into lengths of 3mm, 5mm, and 7mm, and are matched according to a mass ratio of 3mm:5mm:7mm of 30%:50%:20%;

[0047] S2: The polyethylene oxide with a molecular weight of 100000 is dissolved and configured into a solution of 5g / L for standby;

[0048] S3: The alumina fibers, aramid pulp fibers, aramid fibrid fibers, and polyethylene oxide solution are added in proportions of 50wt%, 30wt%, 17wt%, and 3wt%, respectively, and are dispersed at 20000rpm with tap water to obtain a mixed suspension system A with a fiber slurry content of 3g / L;

[0049] S4: The mixed suspension system A is subjected to vacuum-assisted filtration dewatering on a 600-900 mesh filter screen, and then is hot-pressed and dried at 110°C and a pressure of 8MPa for 15min to form an alumina fiber / aramid fiber composite paper with a basis weight of 70g / m 2 ;

[0050] S5: The obtained alumina fiber / aramid pulp fiber composite paper is hot-pressed at a high temperature of 250°C and a pressure of 12MPa for 8min to obtain an alumina fiber-based flexible fire-resistant cable core wrapping tape.

[0051] Example 3

[0052] The present embodiment discloses a preparation process of an alumina fiber-based flexible fire-resistant cable core wrapping tape material, comprising the following steps:

[0053] S1: The alumina fibers with a diameter of 10 microns are cut into lengths of 3mm, 5mm, and 7mm, and are matched according to a mass ratio of 3mm:5mm:7mm of 30%:50%:20%;

[0054] S2: The polyethylene oxide with a molecular weight of 100000 is dissolved and configured into a solution of 5g / L for standby;

[0055] S3: alumina fiber, aramid pulp fiber, aramid fiber, polyethylene oxide solution were added in tap water in the ratio of 50wt%, 30wt%, 17wt%, 3wt%, and dispersed at 20000rpm to obtain a mixed suspension system A with fiber slurry content of 3g / L;

[0056] S4: the mixed suspension system A was vacuum-assisted filtered and dewatered on a 600-900 mesh filter screen, and then hot-pressed and dried at 100℃ and 8MPa pressure for 19min to form an alumina fiber / aramid fiber composite paper with a basis weight of 70g / m 2 ;

[0057] S5: the obtained alumina fiber / aramid pulp fiber composite paper was hot-pressed and finished at 250℃ and 12MPa pressure for 8min to obtain an alumina fiber-based flexible fire-resistant cable core wrapping tape.

[0058] Example 4

[0059] The present embodiment discloses a preparation process of an alumina fiber-based flexible fire-resistant cable core wrapping tape material, comprising the following steps:

[0060] S1: alumina fibers with a diameter of 7 microns were cut into lengths of 3mm, 5mm, and 7mm, and were matched in a mass ratio of 3mm:5mm:7mm at 30%:50%:20%;

[0061] S2: polyethylene oxide with a molecular weight of 100000 was dissolved to prepare a 5g / L solution for standby;

[0062] S3: alumina fiber, aramid pulp fiber, aramid fiber, polyethylene oxide solution were added in tap water in the ratio of 50wt%, 30wt%, 17wt%, 3wt%, and dispersed at 20000rpm to obtain a mixed suspension system A with fiber slurry content of 2.5g / L;

[0063] S4: the mixed suspension system A was vacuum-assisted filtered and dewatered on a 900 mesh filter screen, and then hot-pressed and dried at 95℃ and 8MPa pressure for 18min to form an alumina fiber / aramid fiber composite paper with a basis weight of 70g / m 2 ;

[0064] S5: the obtained alumina fiber / aramid pulp fiber composite paper was hot-pressed and finished at 240℃ and 11MPa pressure for 7min to obtain an alumina fiber-based flexible fire-resistant cable core wrapping tape.

[0065] Example 5

[0066] The present embodiment discloses a preparation process of an alumina fiber-based flexible fire-resistant cable core wrapping tape material, comprising the following steps:

[0067] S1: Cut alumina fibers with a diameter of 8 micrometers into lengths of 3mm, 5mm, and 7mm, and mix them in a mass ratio of 3mm:5mm:7mm of 30%:50%:20%.

[0068] S2: Dissolve polyethylene oxide with a molecular weight of 100,000 to prepare a 5 g / L solution for later use;

[0069] S3: Alumina fiber, aramid pulp fiber, aramid precipitated fiber, and polyethylene oxide solution are added to tap water in proportions of 50wt%, 30wt%, 17wt%, and 3wt% and dispersed at 20,000 rpm to obtain a mixed suspension system A with a fiber pulp content of 3 g / L.

[0070] S4: The mixed suspension system A was vacuum-assisted filtered and dehydrated on an 800-mesh filter, followed by hot-pressing and drying at 100℃ and 8MPa pressure for 20 minutes to form a product with a basis weight of 70g / m³. 2 Alumina fiber / aramid fiber composite paper;

[0071] S5: The obtained alumina fiber / aramid pulp fiber composite paper is hot-pressed at 225℃ and 7MPa pressure for 7 minutes to obtain alumina fiber-based flexible fire-resistant cable core wrapping tape.

[0072] The performance of the cable core wrappings obtained in Examples 1-5 was tested, and the results are shown in Table 1.

[0073] Table 1. Performance parameters of the cable core wrapping obtained in Examples 1-5

[0074]

[0075] As can be seen from the above results, the cable core wrapping tape provided by the present invention exhibits excellent temperature resistance. This is because alumina fiber itself does not contain combustible components. Alumina itself is an oxide and does not have the possibility of re-combustion, thus essentially eliminating combustion and even acting as a fireproof material. Furthermore, alumina fiber accounts for about 50% of the core wrapping tape, isolating aramid fiber and preventing heat from accumulating in the aramid fiber and causing carbonization. In addition, because alumina fiber itself has good thermal conductivity, it can prevent heat accumulation.

[0076] The SEM image of the cable core wrapping obtained in Example 2 is shown below. Figure 2 As shown, by Figure 2 It can be seen that the surface of the cable core tape obtained after hot pressing does not show sheepskin-like appearance and has good bonding effect; among them, the aramid pulp fiber helps to form a mesh structure, which avoids the shedding of alumina fiber.

[0077] The above merely describes the preferred embodiments of the present application, and it should be noted that, for those skilled in the art, some improvements and refinements can be made without departing from the principles of the present application, and these improvements and refinements should also be considered as the protection scope of the present application.

Claims

1. A process for the preparation of a flexible refractory cable core wrap based on alumina fibers, characterized in that, The method comprises the following steps: S1: dissolving polyethylene oxide with a molecular weight of ≥100000 to prepare a solution with a concentration of 3-10 g / L for standby; S2: dispersing alumina fibers, aramid pulp fibers, aramid fibrid fibers and polyethylene oxide solution in water at a ratio of 50wt%, 30wt%, 17wt% and 3wt% to obtain a mixed suspension A with a concentration of 2-3 g / L; The alumina fibers comprise fiber segments with lengths of 3 mm, 5 mm and 7 mm, and the mass ratio of the fiber segments with lengths of 3 mm, 5 mm and 7 mm is (25-35):(45-55):(15-25); S3: after filtering the mixed suspension A, hot-press drying at 95-110 ℃ and 5-10 MPa for 15-20 min to form a fiber composite paper; S4: hot-press finishing the obtained fiber composite paper at 220-250 ℃ and 10-15 MPa for 5-8 min to obtain a cable core wrapping tape.

2. The process for preparing a cable core wrap according to claim 1, characterized in that, The aramid pulp fibers are para-aramid fibers; and the aramid fibrid fibers are meta-aramid fibers.

3. Process for the production of a cable core wrapping according to claim 1 or 2, characterized in that, The specific surface area of the aramid fibrid is ≥ 6 m 2 / g.

4. The process for preparing a cable core wrap of claim 1, wherein, The mesh number is 600-700 meshes; the gram weight of the fiber composite paper is 60-70 g / m 2 .

Images