CN111681811A - A kind of flexible fireproof cable and preparation method of thermal insulation layer thereof - Google Patents

Abstract

The invention discloses a flexible fireproof cable, comprising twisted copper wires, mica tapes wrapped around the twisted copper wires, and insulating layers extruded and wrapped around the mica tapes. The thermal layer is a mineral composite material; the mineral composite material includes a composite mineral powder and a silicone resin in a mass ratio of 3:1. The composite mineral powder contains 85-90 parts by mass of silicate, 2-3 parts by mass of a sintering agent and 7 parts by mass of an oxide mixture consisting of alumina, potassium oxide, sodium oxide, calcium oxide and iron oxide; the sintering agent is by mass It consists of 70 parts of silicon oxide, 20 parts of calcium oxide and 10 parts of magnesium oxide; the mass percentage content of aluminum oxide, potassium oxide, sodium oxide, calcium oxide and iron oxide in the oxide mixture is not less than 1%. The invention also discloses a preparation method of the thermal insulation layer of the flexible fireproof cable. The flexible fireproof cable of the invention is convenient for laying, the preparation is not limited by the length, and the thermal insulation layer of the mineral composite material is ceramicized to protect the inside of the cable in case of fire.

Description

A kind of flexible fireproof cable and preparation method of thermal insulation layer thereof

technical field

The invention belongs to the field of cables, and in particular relates to a flexible fireproof cable and a preparation method of a thermal insulation layer thereof.

Background technique

When a fire occurs, the normal operation of fire emergency equipment is very important for the safe evacuation of personnel, control of fire spread, and reduction of fire losses. Therefore, the electrical distribution lines of fire emergency equipment ensure that the power supply of the fire equipment is not interrupted in the event of a fire, and it is critical to ensure the duration of the power supply. The traditional fireproof cable is a cable with a seamless copper tube sheath on the outer layer, magnesium oxide crystal powder filled in the middle as an insulating material, and a conductor composed of a single-strand copper rod. The investment cost of this kind of cable production equipment is high, and the product cannot be produced in large lengths. The products are expensive, the joints are susceptible to moisture, and the product has poor bending properties, resulting in difficult construction and large construction workload. And if this kind of cable adopts non-metallic sheath, the sheath is damaged in fire, its fireproof performance cannot be guaranteed, and a large amount of smoke is generated after burning, so it is not suitable for personnel to evacuate safely.

In order to solve the inherent defects of traditional fireproof cables, flexible fireproof cables are more and more recognized by customers and have been used in basic industry and civil construction. The so-called "flexible fireproof cable" in the prior art is actually a derivation of the above-mentioned "fireproof cable", that is, a layer of weldable, embossed copper tape is longitudinally wrapped around the stranded conductor and then wrapped with a ribbon. cable jacket. The structure of the "fireproof cable" has two fatal weaknesses: one is that the insulation layer is made of ribbons. In the event of a fire, the ribbons in the cable will become powder in the fire, and the powder is easy to fall off and lead to the core of the cable. It collides with the core, the core and the copper sheath. Second, the sheath is welded and embossed with copper strip longitudinally, and the copper strip becomes hard after embossing. The weakness of the first one leads to the fact that the cable cannot be annealed to restore the softness of the copper strip, and it becomes hard and irrecoverable after embossing, which is contrary to "flexibility". Based on the current situation of fireproof cables, a real flexible fireproof cable is urgently needed.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a flexible fireproof cable, which has flexibility, is convenient for continuous large-length production, and can effectively prevent damage to the wire core caused by flame combustion.

The technical scheme of the present invention is:

A flexible fireproof cable, comprising twisted copper wires, a mica tape wrapped around the twisted copper wires, an insulating layer extruded outside the mica tape, and an insulating layer is also extruded outside the insulating layer , the thermal insulation layer is a mineral composite material; the mineral composite material comprises a composite mineral powder and a silicone resin with a mass ratio of 3:1;

The composite mineral powder comprises 85-90 parts by mass of silicate, 2-3 parts by mass of sintering agent and 7 parts by mass of an oxide mixture consisting of alumina, potassium oxide, sodium oxide, calcium oxide and iron oxide; wherein : the sintering agent is composed of 70 parts by mass of silicon oxide, 20 parts of calcium oxide and 10 parts of magnesium oxide; the mass percentage contents of aluminum oxide, potassium oxide, sodium oxide, calcium oxide and iron oxide in the oxide mixture are all not less than 1%.

The thermal insulation layer of the flexible fireproof cable of the present invention is a mineral composite material; the mineral composite material comprises composite mineral powder and silicone resin with a mass ratio of 3:1, and the composite mineral powder also contains 85-90 mass parts of silicate and 2-3 parts by mass of sintering agent. In the process of making the cable, the mineral composite material is heated and cross-linked into a network structure and fixed on the outside of the insulating layer during extrusion, and acts as a skeleton to protect the inside of the cable when the cable is in normal use. At high temperature of the material composite material, the silicate, sintering agent, oxide mixture and other substances in the composite mineral powder react rapidly under the action of high temperature to form a hard ceramic shell and fix it on the cable to prevent the flame from continuing to damage the cable. , to ensure that the cable continues to work. In particular, the added sintering agent and the oxide mixture consisting of aluminium oxide, potassium oxide, sodium oxide, calcium oxide and iron oxide, which have a synergistic effect, reduce the ceramization temperature of the silicate and, therefore, accelerate the mineral recombination The thermal insulation layer of the material is ceramicized immediately in case of fire, and the inside of the cable is protected in time. The thermal conductivity of the mineral composite material and its ceramicization is low, which can prevent the external heat from entering the conductive wire core when a fire occurs, and ensure that the current carrying capacity of the conductive wire core will not drop significantly.

The flexible fireproof cable of the present invention can be manufactured by continuously extruding the thermal insulation layer like a normal cable, and the length of the prepared cable is not limited; and the thermal insulation layer of the prepared mineral composite material is flexible, which can be convenient Laying, to meet the convenient construction of different occasions.

Preferably, a glass fiber tape is wrapped around the heat insulating layer, and a low-smoke halogen-free sheath is extruded on the outside of the glass fiber tape. With the addition of glass fiber tape, the thermal insulation layer can be mechanically protected. Using LSZH sheaths can be more environmentally friendly and will not smoke in the event of a fire.

Preferably, the wire core of the stranded copper wire is not larger than 0.5 mm, and the fireproof cable made of such a wire core is more flexible.

Preferably, the mica tape is a multi-layer double-sided synthetic refractory mica tape.

Preferably, the silicate is sodium silicate or calcium silicate.

The present invention also provides a method for preparing the thermal insulation layer of the above-mentioned flexible fireproof cable, comprising the following steps:

Step 1: Prepare compound mineral powder

Weigh 85-90 parts by mass of silicate, 2-3 parts by mass of sintering agent and 7 parts by mass of the oxide mixture consisting of aluminum oxide, potassium oxide, sodium oxide, calcium oxide and iron oxide, and mix to form a composite Mineral powder; wherein: the sintering agent is composed of 70 parts of silicon oxide, 20 parts of calcium oxide and 10 parts of magnesium oxide by mass; in the oxide mixture, aluminum oxide, potassium oxide, sodium oxide, calcium oxide and iron oxide are The mass percentage content is not less than 1%;

Step 2: Kneading and Extrusion

The silicone resin and the silicone resin containing 1-2% cross-linking agent DCP are uniformly stirred and mixed at a mass ratio of 1:0.7-1.5, and the mixing temperature is not more than 25°C; 3 times the mass of the composite mineral powder is added to knead into a mineral. Substance composites are then extruded on a silicone rubber extrusion line.

The beneficial effects of the present invention are:

The flexible fireproof cable of the invention uses the thermal insulation layer of the mineral composite material to protect the cable, avoids the drawbacks caused by the use of the metal sheath, the flexible thermal insulation layer is flexible during the daily use of the cable, and is convenient for laying and construction, and It has a protective effect on the cable; in the event of a fire, the thermal insulation layer of the mineral composite material can be instantly ceramicized to protect the inside of the cable in time. Moreover, the preparation of the flexible fireproof cable of the present invention is not limited by the length, and the preparation is convenient.

Description of drawings

FIG. 1 is a schematic structural diagram of the flexible fireproof cable of the present invention.

In the picture: 1. Stranded copper wire; 2. Mica tape; 3. Insulation layer; 4. Insulation layer; 5. Glass fiber tape; 6. Low-smoke halogen-free sheath.

Detailed ways

The present invention will be described in detail below with reference to the embodiments and accompanying drawings.

FIG. 1 is a flexible fireproof cable of the present invention, which includes stranded copper wire 1, mica tape 2 wrapped around the stranded copper wire 1, and an insulating layer 3 extruded and wrapped outside the mica tape. The insulating layer 3 is also extruded with a heat insulating layer 4, and the heat insulating layer 4 is a mineral composite material; the mineral composite material comprises a composite mineral powder and a silicone resin with a mass ratio of 3:1;

The composite mineral powder comprises 85-90 parts by mass of silicate, 2-3 parts by mass of sintering agent and 7 parts by mass of an oxide mixture consisting of alumina, potassium oxide, sodium oxide, calcium oxide and iron oxide; wherein: The sintering agent is composed of 70 parts by mass of silicon oxide, 20 parts of calcium oxide and 10 parts of magnesium oxide; the mass percentage contents of aluminum oxide, potassium oxide, sodium oxide, calcium oxide and iron oxide in the oxide mixture are all different. less than 1%.

The preparation method of the thermal insulation layer of the above-mentioned flexible fireproof cable in the present invention comprises the following steps:

Step 1: Prepare compound mineral powder

Weigh 85-90 parts by mass of silicate, 2-3 parts by mass of sintering agent and 7 parts by mass of the oxide mixture consisting of aluminum oxide, potassium oxide, sodium oxide, calcium oxide and iron oxide, and mix to form composite mineral powder ; wherein: the sintering agent is composed of 70 parts of silicon oxide, 20 parts of calcium oxide and 10 parts of magnesium oxide by mass; the mass percentages of aluminum oxide, potassium oxide, sodium oxide, calcium oxide and iron oxide in the oxide mixture The content is not less than 1%.

Step 2: Kneading and Extrusion

Mix the silicone resin and the silicone resin containing 1-2% cross-linking agent DCP in a planetary mixer at a mass ratio of 1:0.7-1.5, and fully dissipate heat during mixing to ensure that the mixing temperature is not greater than 25 °C. Then, add 3 times the mass of the composite mineral powder to the mixed silicone resin on a kneader with a vacuum function for kneading, and then extrude it into a mineral composite material on a silicone rubber extrusion line. When fireproofing the cable, it is extruded on the outside of the cable insulation layer to form a thermal insulation layer.

Example 1

To make a flexible fireproof cable, the method is as follows:

Step 1: Prepare compound mineral powder

1. Preparation of sintering agent: 70 parts by mass of silicon oxide powder, 20 parts by mass of calcium oxide powder and 10 parts by mass of magnesium oxide powder are mixed uniformly, which is a sintering agent.

2. Preparation of oxide mixture: Take 1 part of alumina, 30 parts of potassium oxide, 30 parts of sodium oxide, 30 parts of calcium oxide and 9 parts of iron oxide by weight, and mix them evenly.

3. Preparation of composite mineral powder: Weigh 85 parts by mass of calcium silicate, 3 parts by mass of the sintering agent prepared above and 7 parts by mass of the oxide mixture prepared above, and mix them uniformly to form a composite mineral powder.

Step 2: Kneading and Extrusion

Mix the silicone resin and the silicone resin containing 1% cross-linking agent DCP in a planetary mixer at a mass ratio of 1:1, fully dissipate heat during mixing, and ensure that the mixing temperature is not greater than 25°C. Then, add 3 times the mass of the composite mineral powder to the above-mentioned mixed silicone resin on a kneader with a vacuum function, and knead it to prepare a mineral composite material.

Step 3: Make the Cable

When making the cable, first coat the double-sided synthetic refractory mica tape on the stranded copper wire with 0.5mm core; then extrude the insulating layer, and then extrude the outer periphery of the above-mentioned insulating layer on the silicone rubber extrusion line The mineral composite material prepared above is an insulating layer, which is vulcanized in hot air at 200°C to 300°C. Then, a glass fiber tape can also be wrapped around the heat insulation layer, and the glass fiber tape is extruded and wrapped with a low-smoke halogen-free sheath.

Example 2

To make a flexible fireproof cable, the method is as follows:

Step 1: Prepare compound mineral powder

1. The sintering agent was prepared by the same method as in Example 1.

2. Preparation of oxide mixture: take 30 parts of alumina, 1 part of potassium oxide, 9 parts of sodium oxide, 30 parts of calcium oxide and 30 parts of iron oxide by weight, and mix them evenly.

3. Preparation of composite mineral powder: Weigh 90 parts by mass of sodium silicate, 2 parts by mass of the sintering agent prepared above and 7 parts by mass of the oxide mixture prepared above, and mix to form a composite mineral powder.

Step 2: Kneading and Extrusion

Mix the silicone resin and the silicone resin containing 2% cross-linking agent DCP in a planetary mixer at a mass ratio of 1:0.7, fully dissipate heat during mixing, and ensure that the mixing temperature is not greater than 25°C. Then, add 3 times the mass of the composite mineral powder to the above-mentioned mixed silicone resin on a kneader with a vacuum function, and knead it to prepare a mineral composite material.

Step 3: Make the Cable

Using the same method as Example 1, the mineral composite material prepared in this example is extruded into a thermal insulation layer to manufacture a flexible fireproof cable.

Example 3

To make a flexible fireproof cable, the method is as follows:

Step 1: Prepare compound mineral powder

1. The sintering agent was prepared by the same method as in Example 1.

2. Preparation of oxide mixture: take 30 parts of alumina, 30 parts of potassium oxide, 1 part of sodium oxide, 9 parts of calcium oxide and 30 parts of iron oxide by weight, and mix them evenly.

3. Preparation of composite mineral powder: Weigh 90 parts by mass of calcium silicate, 2 parts by mass of the sintering agent prepared above and 7 parts by mass of the oxide mixture prepared above, and mix them uniformly to form a composite mineral powder.

Step 2: Kneading and Extrusion

Mix the silicone resin and the silicone resin containing 1.5% cross-linking agent DCP in a planetary mixer at a mass ratio of 1:1.5, fully dissipate heat during mixing, and ensure that the mixing temperature is not greater than 25°C. Then, add 3 times the mass of the composite mineral powder to the above-mentioned mixed silicone resin on a kneader with a vacuum function, and knead it to prepare a mineral composite material.

Step 3: Make the Cable

Using the same method as Example 1, the mineral composite material prepared in this example is extruded into a thermal insulation layer to manufacture a flexible fireproof cable.

Example 4

To make a flexible fireproof cable, the method is as follows:

Step 1: Prepare compound mineral powder

1. The sintering agent was prepared by the same method as in Example 1.

2. Preparation of oxide mixture: take 30 parts of alumina, 9 parts of potassium oxide, 30 parts of sodium oxide, 1 part of calcium oxide and 30 parts of iron oxide by weight, and mix them evenly.

3. Preparation of composite mineral powder: Weigh 85 parts by mass of sodium silicate, 3 parts by mass of the sintering agent prepared above and 7 parts by mass of the oxide mixture prepared above, and mix uniformly to form a composite mineral powder.

Step 2: Kneading and Extrusion

Mix the silicone resin and the silicone resin containing 1.5% cross-linking agent DCP in a planetary mixer at a mass ratio of 1:1.2, fully dissipate heat during mixing, and ensure that the mixing temperature is not greater than 25°C. Then, add 3 times the mass of the composite mineral powder to the above-mentioned mixed silicone resin on a kneader with a vacuum function, and knead it to prepare a mineral composite material.

Step 3: Make the Cable

Using the same method as Example 1, the mineral composite material prepared in this example is extruded into a thermal insulation layer to manufacture a flexible fireproof cable.

Example 5

To make a flexible fireproof cable, the method is as follows:

Step 1: Prepare compound mineral powder

1. The sintering agent was prepared by the same method as in Example 1.

2. Preparation of oxide mixture: take 9 parts of alumina, 30 parts of potassium oxide, 30 parts of sodium oxide, 30 parts of calcium oxide and 1 part of iron oxide by weight, and mix them evenly.

3. Preparation of composite mineral powder: Weigh 85 parts by mass of calcium silicate, 3 parts by mass of the sintering agent prepared above and 7 parts by mass of the oxide mixture prepared above, and mix them uniformly to form a composite mineral powder.

Step 2: Kneading and Extrusion

Mix the silicone resin and the silicone resin containing 2% cross-linking agent DCP in a planetary mixer with a mass ratio of 1:0.9, fully dissipate heat during mixing, and ensure that the mixing temperature is not greater than 25°C. Then, add 3 times the mass of the composite mineral powder to the above-mentioned mixed silicone resin on a kneader with a vacuum function, and knead it to prepare a mineral composite material.

Step 3: Make the Cable

Using the same method as Example 1, the mineral composite material prepared in this example is extruded into a thermal insulation layer to manufacture a flexible fireproof cable.

Fire performance test:

The flexible fireproof cables produced in Examples 1 to 5 were tested for fire resistance, and they all passed the national standard GB/T12666-2008 Class A 950℃ 90min test; also passed the IA class 950℃- 1000 ℃ test; also passed the test specified in British BS6387-1994 for A grade 650 ℃ 3h, B grade 750 ℃ 3h, C grade 950 ℃ 3h test, and the flexible fireproof cable prepared in the above embodiments of the present invention also Resistant to water spray and mechanical impact. It can be seen that the flexible fireproof cable prepared by the present invention has excellent fireproof performance. In addition, using the method of the present invention to prepare the flexible fireproof cable, the thermal insulation layer is flexible and extruded on the production line, so it can be continuously produced, and the length of the finished product can be produced on demand without limitation. The flexible fireproof cable of the invention has a bending radius of up to 7D (D is the outer diameter of the cable), has excellent bending performance, and the cable ends do not need to use special terminal knots, which is convenient for laying, not easy to absorb moisture, and has a simple structure. Small size, convenient production and low price.

In addition, by using the method of the present invention, the insulating layer of the flexible fireproof cable of the present invention can also be extruded and wrapped outside the insulating layer of the multi-core cable, thereby making a multi-core flexible cable. The same length of the multi-core flexible cable can also be used as required. Production is not limited, and it can be continuously produced in large lengths.

It should be noted here that the descriptions of these embodiments are used to help the understanding of the present invention, but do not constitute a limitation of the present invention. In addition, the technical features involved in the various embodiments of the present invention described above can be combined with each other as long as there is no conflict with each other. In addition, the above are only some embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work belong to the present invention. scope of protection.

Claims (6)

1. a flexible fireproof cable, comprising stranded copper wire, mica tape wrapped outside the stranded copper wire, and an insulating layer extruded outside the mica tape, characterized in that outside the insulating layer The heat insulating layer is extruded and wrapped, and the heat insulating layer is a mineral composite material; the mineral composite material comprises a composite mineral powder and a silicone resin with a mass ratio of 3:1; The composite mineral powder comprises 85-90 parts by mass of silicate, 2-3 parts by mass of sintering agent and 7 parts by mass of an oxide mixture consisting of alumina, potassium oxide, sodium oxide, calcium oxide and iron oxide; Wherein: the sintering agent is composed of 70 parts by mass of silicon oxide, 20 parts of calcium oxide and 10 parts of magnesium oxide; the mass percentage content of aluminum oxide, potassium oxide, sodium oxide, calcium oxide and iron oxide in the oxide mixture are not less than 1%. 2 . The flexible fireproof cable according to claim 1 , wherein a glass fiber tape is wrapped around the heat insulating layer, and a low-smoke halogen-free sheath is extruded on the outside of the glass fiber tape. 3 . 3 . The flexible fireproof cable according to claim 1 , wherein the core of the stranded copper wire is not larger than 0.5 mm. 4 . 4. The flexible fireproof cable according to claim 1, wherein the mica tape is a multi-layer double-sided synthetic fire-resistant mica tape. 5. The flexible fireproof cable according to claim 1, wherein the silicate is sodium silicate or calcium silicate. 6. The preparation method of the thermal insulation layer of the flexible fireproof cable according to one of claims 1 to 5, characterized in that, comprising the steps of: Step 1: Prepare compound mineral powder Weigh 85-90 parts by mass of silicate, 2-3 parts by mass of sintering agent and 7 parts by mass of the oxide mixture consisting of aluminum oxide, potassium oxide, sodium oxide, calcium oxide and iron oxide, and mix to form composite mineral powder ; wherein: the sintering agent is composed of 70 parts of silicon oxide, 20 parts of calcium oxide and 10 parts of magnesium oxide by mass; the mass percentages of aluminum oxide, potassium oxide, sodium oxide, calcium oxide and iron oxide in the oxide mixture The content is not less than 1%; Step 2: Kneading and Extrusion The silicone resin and the silicone resin containing 1-2% cross-linking agent DCP are uniformly stirred and mixed at a mass ratio of 1:0.7-1.5, and the mixing temperature is not more than 25°C; 3 times the mass of the composite mineral powder is added to knead into a mineral. Substance composites are then extruded on a silicone rubber extrusion line.

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