Insulation layer flame-retardant wire clamp

Abstract

The present application relates to the field of electric power overhaul, in view to the problem of unsafe electric spark generated by wire clamp during work, provide the wire clamp of insulating layer flame retardant, the outer surface of the wire clamp is equipped with insulating layer, the component of the insulating layer includes by weight fraction: base resin 100 parts, load flame retardant sepiolite 20-40 parts, other auxiliary agent 33-65 parts.Sepiolite acts as a filler, also can reduce the amount of lubricant, and the flame retardant is adsorbed in the pore channel of sepiolite, improves the flame retardant performance of flame retardant.

Description

Technical Field

[0001] This invention relates to the field of power maintenance, and in particular to wire clamps with flame-retardant insulation layers. Background Technology

[0002] Wire clamps are tools used for quick wire connections during power maintenance. Because wire connections are live, wire clamps require insulation. For example, patent CN107809011A discloses a temporary wire connection clamp, comprising a handle body with an insulating head at the other end. The insulating head has a first locking head and a second locking head, which can connect to wires inside a cover. An insulating cap can also be fitted onto the insulating head. The first and second locking heads are made of copper-aluminum alloy. This invention's temporary wire connection clamp uses a pressure rod to control the opening and closing of the locking heads, thus easily and securely clamping the wires requiring temporary connection to the line. Disconnection is also convenient, and the entire device is safe to use and not easily detached.

[0003] Considering that the wire joints are exposed during emergency repairs and may generate electrical sparks, it is necessary to further treat the wire clamps with flame retardant to improve the safety of the power maintenance process. Summary of the Invention

[0004] In order to overcome the safety problem of electrical sparks generated during the operation of wire clamps, this invention provides a wire clamp with flame-retardant insulation layer, which has both insulation and flame-retardant properties and is highly safe to use.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A flame-retardant wire clamp with an insulating layer is disclosed. The outer surface of the wire clamp is provided with an insulating layer, the components of which, by weight, include: 100 parts of matrix resin, 20-40 parts of sepiolite loaded with a flame retardant, and 33-65 parts of other additives. Sepiolite acts as a filler and, moreover, can adsorb large amounts of water or polar substances, including low-polarity substances, within its channels and pores. Therefore, sepiolite has a strong adsorption capacity, adsorbing the flame retardant within its pores and improving its flame-retardant properties.

[0007] Preferably, the flame retardant is hexa(1-oxo-1-phospha-2,6,7-trioxabicyclo[2,2,2]octane-4-methylene)cyclotriphosphazene, abbreviated as PEPAP. PEPAP has good thermal stability and excellent char-forming ability. The thermal degradation of PEPAP involves the thermal breakage of phosphate ester bonds to generate phosphoric acid, which catalyzes char formation, dehydrating the char source, and releasing non-flammable gases from the gas source, causing the char layer to expand and foam, ultimately forming a char layer that effectively protects the matrix by providing thermal and oxygen insulation. PEPAP has a good flame retardant effect on resins; the addition of PEPAP can delay the thermal degradation of resins, and the limiting oxygen index and vertical burning rating of the insulation layer are also significantly improved.

[0008] Preferably, the method for preparing the sepiolite loaded with the flame retardant is as follows:

[0009] 1) The sepiolite was ultrasonically treated with hydrochloric acid, filtered, washed and dried;

[0010] 2) Add PEPAP to acetonitrile, heat to 60-80℃ and stir vigorously, add the sepiolite powder treated in step 1), continue stirring for 1-3 hours, let stand overnight, filter and dry to obtain sepiolite loaded with flame retardant.

[0011] Preferably, the mass ratio of sepiolite to PEPAP is 10:(3-5).

[0012] Preferably, the hydrochloric acid in step 1) has a mass fraction of 10-15%, and the ultrasonic time is 10-20 min.

[0013] First, sepiolite is ultrasonically treated in hydrochloric acid to remove impurities and increase its internal porosity. Then, sepiolite is added to a PEPAP dispersion, stirred vigorously, and allowed to stand. The PEPAP is then adsorbed into the pores of the sepiolite. Compared to directly adding PEPAP to the resin, this invention, by adsorbing PEPAP into the pores of the sepiolite, further enhances its flame-retardant properties. This is because ① PEPAP is an intumescent flame retardant, and its flame-retardant mechanism involves a series of complex physicochemical reactions upon heating to generate an intumescent porous carbon layer, which is a crucial factor in its flame-retardant effect. ② The crystal structure of sepiolite has a continuous silicon-oxygen tetrahedral layer. Each silicon-oxygen tetrahedron shares two vertices connected to three adjacent tetrahedra. The active oxygen in the tetrahedron rotates periodically along the b-axis, thus forming open channels of fixed size parallel to the chain. At the edge of the octahedron, two water molecules combine with magnesium ions, participating in octahedral coordination. ③ PEPAP is adsorbed into the pores of sepiolite. After the first ignition, a large number of expanded non-combustible char layers are formed on the surface of PEPAP. Due to the constraint of sepiolite, the expanded char layer overflows from the pores of sepiolite, forming a structure in which sepiolite and expanded char layer mutually restrain each other. This can further strengthen the strength of the non-combustible char layer, thereby greatly delaying the time of the second ignition and improving the flame retardant performance of the system.

[0014] Preferably, the matrix resin is cross-linked polyethylene. Compared with ordinary polyethylene, cross-linked polyethylene has better heat resistance, insulation properties, mechanical properties and chemical resistance, and is better suited for the application of wire clamps.

[0015] Preferably, the other additives are present in the following proportions by weight: 30-50 parts plasticizer, 3-10 parts stabilizer, and 0-5 parts lubricant. Sepiolite crystals have a layered chain structure and excellent rheological properties, thus reducing or even eliminating the need for lubricant.

[0016] Preferably, the plasticizer is selected from di(2-ethylhexyl) phthalate, diheptyl phthalate, and diisodecyl phthalate; the stabilizer is dibasic lead stearate; and the lubricant is selected from stearic acid and its esters, stearates, polyethylene wax, paraffin wax, stearamide, and oleamide.

[0017] As a preferred method, the preparation method of the insulating layer is as follows: (1) First, add the matrix resin to anhydrous ethanol and mix evenly; then add sepiolite loaded with flame retardant and other additives, and stir to obtain the coating;

[0018] (2) The coating obtained in step (1) is applied to the mold and cured to form an insulating layer.

[0019] Preferably, the stirring temperature in step (1) is 60-80℃ and the stirring time is 8-10h.

[0020] Preferably, the thickness of the insulating layer is 1-3 cm.

[0021] Therefore, the beneficial effects of the present invention are as follows: (1) Sepiolite acts as a filler on the one hand, and reduces or even eliminates the use of lubricant on the other hand. (2) The intumescent flame retardant PEPAP is adsorbed in the pores of sepiolite. After the first ignition, PEPAP expands to form a non-combustible char layer, which cooperates with the silicon-oxygen tetrahedral layer structure of sepiolite to improve the strength of the non-combustible char layer, thereby greatly delaying the time of the second ignition and improving the flame retardant performance of the system. Detailed Implementation

[0022] The technical solution of the present invention will be further described below through specific embodiments.

[0023] In this invention, unless otherwise specified, the raw materials and equipment used can be purchased from the market or are commonly used in the field. The methods in the embodiments, unless otherwise specified, are conventional methods in the field.

[0024] General Implementation Examples

[0025] A flame-retardant wire clamp with an insulating layer, wherein the outer surface of the wire clamp is provided with an insulating layer, the components of which, by weight, include: 100 parts of cross-linked polyethylene, 20-40 parts of sepiolite loaded with flame retardant, 30-50 parts of plasticizer (di(2-ethylhexyl) phthalate, diheptyl phthalate or diisodecyl phthalate), 3-10 parts of stabilizer dibasic lead stearate, and 0-5 parts of lubricant (stearic acid and its esters, stearates, polyethylene wax, paraffin wax, stearamide or oleamide).

[0026] The preparation method of the insulating layer is as follows: (1) Sepiolite is ultrasonically treated with hydrochloric acid of mass fraction 10-15% for 10-20 min, filtered, washed and dried; PEPAP is added to acetonitrile, the mass ratio of sepiolite to PEPAP is 10:(3-5), heated to 60-80℃ and stirred vigorously, the treated sepiolite powder is added and stirred for 1-3 h and then left to stand overnight, filtered and dried to obtain sepiolite loaded with flame retardant;

[0027] (2) According to the above proportion, first add the base resin to anhydrous ethanol and mix evenly; then add the sepiolite, plasticizer, stabilizer and lubricant loaded with flame retardant, and stir at 60-80℃ for 8-10h to obtain the coating.

[0028] (3) The coating agent is applied to the mold and cured to obtain an insulating layer with a thickness of 1-3cm.

[0029] Example 1

[0030] A flame-retardant wire clamp with an insulating layer, wherein the outer surface of the wire clamp is provided with an insulating layer, and the components of the insulating layer by weight are: 100 parts of cross-linked polyethylene, 30 parts of sepiolite loaded with flame retardant, 40 parts of di(2-ethylhexyl) phthalate plasticizer, 5 parts of dibasic lead stearate stabilizer, and 3 parts of stearic acid lubricant.

[0031] The method for preparing the insulating layer is as follows:

[0032] (1) The sepiolite was ultrasonically treated with 10% hydrochloric acid for 20 min, filtered, washed and dried; PEPAP was added to acetonitrile, the mass ratio of sepiolite to PEPAP was 10:4, heated to 70°C and stirred vigorously, the treated sepiolite powder was added and stirred for 2 h, then left to stand overnight, filtered and dried to obtain sepiolite loaded with flame retardant.

[0033] (2) According to the above proportion, first add cross-linked polyethylene to anhydrous ethanol and mix evenly; then add the sepiolite loaded with flame retardant, plasticizer, stabilizer and lubricant, and stir at 70°C for 9 hours to obtain the coating.

[0034] (3) The coating agent is applied to the mold and cured to obtain an insulating layer with a thickness of 2cm.

[0035] Example 2

[0036] A flame-retardant wire clamp with an insulating layer, wherein the outer surface of the wire clamp is provided with an insulating layer, and the components of the insulating layer by weight are: 100 parts of cross-linked polyethylene, 40 parts of sepiolite loaded with flame retardant, 30 parts of diheptyl phthalate plasticizer, and 3 parts of dibasic lead stearate stabilizer.

[0037] The method for preparing the insulating layer is as follows:

[0038] (1) The sepiolite was ultrasonically treated with 10% hydrochloric acid for 20 min, filtered, washed and dried; PEPAP was added to acetonitrile, the mass ratio of sepiolite to PEPAP was 10:3, heated to 60℃ and stirred vigorously, the treated sepiolite powder was added and stirred for 3 h, then left to stand overnight, filtered and dried to obtain sepiolite loaded with flame retardant.

[0039] (2) According to the above proportion, first add the base resin to anhydrous ethanol and mix evenly; then add the sepiolite loaded with flame retardant, plasticizer and stabilizer, and stir at 60°C for 10h to obtain the coating.

[0040] (3) The coating agent is applied to the mold and cured to obtain an insulation layer with a thickness of 1 cm.

[0041] Example 3

[0042] A flame-retardant wire clamp with an insulating layer, wherein the outer surface of the wire clamp is provided with an insulating layer, and the components of the insulating layer by weight are: 100 parts of cross-linked polyethylene, 20 parts of sepiolite loaded with flame retardant, 50 parts of diisodecyl phthalate plasticizer, 10 parts of dibasic lead stearate stabilizer, and 5 parts of stearamide lubricant.

[0043] The method for preparing the insulating layer is as follows:

[0044] (1) The sepiolite was ultrasonically treated with 15% hydrochloric acid for 10 min, filtered, washed and dried; PEPAP was added to acetonitrile, the mass ratio of sepiolite to PEPAP was 10:5, heated to 80°C and stirred vigorously, the treated sepiolite powder was added and stirred for 1 h, then left to stand overnight, filtered and dried to obtain sepiolite loaded with flame retardant.

[0045] (2) According to the above proportion, first add the base resin to anhydrous ethanol and mix evenly; then add the sepiolite, plasticizer, stabilizer and lubricant loaded with flame retardant, and stir at 80°C for 8 hours to obtain the coating.

[0046] (3) The coating agent is applied to the mold and cured to obtain a 3cm thick insulation layer.

[0047] Example 4

[0048] The difference from Example 1 is that the mass ratio of sepiolite to PEPAP in step (1) is 10:7.

[0049] Example 5

[0050] The difference from Example 1 is that the mass ratio of sepiolite to PEPAP in step (1) is 10:1.

[0051] Comparative Example 1

[0052] A flame-retardant wire clamp with an insulating layer, wherein the outer surface of the wire clamp is provided with an insulating layer, and the components of the insulating layer by weight are: 100 parts of cross-linked polyethylene, 30 parts of sepiolite, 40 parts of plasticizer di(2-ethylhexyl) phthalate, 5 parts of stabilizer dibasic lead stearate, and 3 parts of lubricant stearic acid.

[0053] The method for preparing the insulating layer is as follows:

[0054] (1) The sepiolite was ultrasonically treated with 10% hydrochloric acid for 20 minutes, filtered, washed and dried to obtain the treated sepiolite;

[0055] (2) According to the above proportion, first add cross-linked polyethylene to anhydrous ethanol and mix evenly; then add the treated sepiolite, plasticizer, stabilizer and lubricant, and stir at 70°C for 9 hours to obtain the coating.

[0056] (3) The coating agent is applied to the mold and cured to obtain an insulating layer with a thickness of 2cm.

[0057] Comparative Example 2

[0058] A flame-retardant wire clamp with an insulating layer, wherein the outer surface of the wire clamp is provided with an insulating layer, and the components of the insulating layer by weight are: 100 parts of cross-linked polyethylene, 9 parts of flame retardant PEPAP, 21 parts of sepiolite, 40 parts of plasticizer di(2-ethylhexyl) phthalate, 5 parts of stabilizer dibasic lead stearate, and 3 parts of lubricant stearic acid.

[0059] The method for preparing the insulating layer is as follows:

[0060] (1) According to the above proportion, first add cross-linked polyethylene to anhydrous ethanol and mix evenly; then add flame retardant, sepiolite, plasticizer, stabilizer and lubricant, and stir at 70°C for 9 hours to obtain coating.

[0061] (2) The coating agent is applied to the mold and cured to obtain an insulating layer with a thickness of 2cm.

[0062] Performance testing

[0063] Mechanical properties, insulation properties, and flammability tests were conducted on the insulation layers of each embodiment and comparative example, and all met the requirements. The flammability test is described in detail below. The test method was as follows: identical portions of the insulation layers were placed under the same flame source to initiate combustion, and the time at which combustion began was recorded. After burning for 10 seconds under the flame source, the wire clamps were removed, and the time from removal of the wire clamps to complete extinguishing of the flames was recorded. The results are shown in the table below.

[0064] Example 1 Example 2 Example 3 Example 4 Example 5 Comparative Example 1 Comparative Example 2 Start of combustion time / s 8.5 8 8.3 8.3 8 4.2 7.1 Extinguishing time / s 1.3 1.9 1.4 1.4 2.6 16.7 8.3

[0065] As can be seen from the table above, the insulating layers prepared in each embodiment of the present invention have good flame retardant properties. Compared with Example 1: ① In Example 2, no lubricant was used, and the flame retardant properties only decreased slightly, with little impact on mechanical and insulating properties, indicating that the presence of sepiolite can indeed reduce or even eliminate the need for lubricant. ② In Example 4, the amount of PEPAP exceeded the preferred range, which had little impact on the initial combustion time, but prolonged the extinguishing time. Therefore, from a cost perspective, it is unnecessary to increase the amount of PEPAP. From a principle perspective, PEPAP is adsorbed into sepiolite. After the first ignition, PEPAP expands to form a non-combustible char layer, which then interacts with the silicon-oxygen tetrahedral layer structure of sepiolite to improve the strength of the non-combustible char layer, thereby greatly delaying the second ignition time and improving the flame retardant properties of the system. Therefore, the best effect can only be achieved when the amounts of PEPAP and sepiolite are matched. Excessive PEPAP does not have enough sepiolite to match, and the gain effect is no longer obvious. ③ In Example 5, the amount of PEPAP was lower than the preferred range, resulting in a decrease in flame retardant properties. ④ In Comparative Example 1, no flame retardant was added, and the flame retardancy of cross-linked polyethylene alone was clearly insufficient to meet the flame retardant requirements. ⑤ In Comparative Example 2, PEPAP was not loaded inside the sepiolite, and the two components were directly added and mixed. The flame retardant performance was far inferior to that of Example 1, especially in terms of the effect on extinguishing time. This proves that the synergy between the two components after PEPAP was loaded into sepiolite achieved a better flame retardant effect.

[0066] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A method for preparing an insulating layer for the outer surface of a wire clamp, characterized in that, By weight, the steps include: (1) Add 100 parts of the base resin to anhydrous ethanol. The base resin is cross-linked polyethylene. Mix evenly. Then add 20-40 parts of sepiolite loaded with flame retardant and 33-65 parts of other additives. Stir to obtain the coating. The method for preparing the sepiolite loaded with flame retardant is as follows: 1) The sepiolite is ultrasonically treated with hydrochloric acid, filtered, washed and dried; 2) Add PEPAP to acetonitrile. PEPAP is hexa(1-oxo-1-phospha-2,6,7-trioxabicyclo[2,2,2]octane-4-methylene)cyclotriphosphazene. Heat to 60-80℃ and stir vigorously. Add the sepiolite powder treated in step 1) and continue stirring for 1-3 hours. Let stand overnight. The mass ratio of sepiolite to PEPAP is 10:3-5. Filter and dry. (2) Apply the coating obtained in step (1) to the mold, cure and form to obtain an insulating layer.

2. The method for preparing the insulating layer for the outer surface of a wire clamp according to claim 1, characterized in that, The mass ratio of sepiolite to PEPAP is 10:

3.

3. The method for preparing the insulating layer for the outer surface of a wire clamp according to claim 1, characterized in that, The mass ratio of sepiolite to PEPAP is 10:

4.

4. The method for preparing the insulating layer for the outer surface of a wire clamp according to claim 1, characterized in that, The mass ratio of sepiolite to PEPAP is 10:

5.

5. The method for preparing an insulating layer for the outer surface of a wire clamp according to claim 1, characterized in that, Step 1) The hydrochloric acid has a mass fraction of 10-15%, and the ultrasonic time is 10-20 min.

6. The method for preparing an insulating layer for the outer surface of a wire clamp according to claim 1, characterized in that, The other additives are present in the following proportions by weight: 30-50 parts plasticizer, 3-10 parts stabilizer, and 0-5 parts lubricant.

7. The method for preparing an insulating layer for the outer surface of a wire clamp according to claim 6, characterized in that, The plasticizer is selected from di(2-ethylhexyl) phthalate, diheptyl phthalate, and diisodecyl phthalate; the stabilizer is dibasic lead stearate; and the lubricant is selected from stearic acid and its esters, stearates, polyethylene wax, paraffin wax, stearamide, and oleamide.

8. The method for preparing an insulating layer for the outer surface of a wire clamp according to claim 1, characterized in that, The stirring temperature in step (1) is 60-80 ℃ and the stirring time is 8-10 h.

9. The method for preparing an insulating layer for the outer surface of a wire clamp according to claim 1 or 8, characterized in that, The thickness of the insulating layer in step (2) is 1-3 cm.