Fireproof polyvinyl chloride material, preparation method thereof and cable sheath

Abstract

The application relates to the technical field of circuit conveying equipment, in particular to a fireproof polyvinyl chloride material and a preparation method thereof and a cable sheath pipe. The fireproof polyvinyl chloride material comprises the following raw materials in parts by weight: 90-110 parts of polyvinyl chloride, 10-20 parts of a compatilizer, 8-15 parts of ammonium polyphosphate and 5-8 parts of an ultraviolet aging resistant additive, wherein the ultraviolet aging resistant additive is a mixture of N,N"-bis(2,2,6,6-tetramethyl-4-piperidyl)-1,6-hexanediamine and a metal hydroxide. The fireproof polyvinyl chloride has excellent flame retardant performance and ultraviolet aging resistance.

Description

Technical Field

[0001] This application relates to the technical field of circuit transmission equipment, and more specifically, it relates to a fire-resistant polyvinyl chloride material, its preparation method, and a cable conduit. Background Technology

[0002] With the rapid development of the global economy and the increasing awareness of environmental protection, the requirements for the quality and performance of wires and cables in various fields are becoming increasingly stringent, and the safety of cables is receiving more and more attention.

[0003] Because cables are installed outdoors, they are exposed to sunlight for extended periods, causing aging and degradation, which in turn leads to surface cracking. Furthermore, with the increasing frequency of fires, the requirements for the fire resistance of electrical wires and cables are becoming more stringent.

[0004] Therefore, there is an urgent need for a PVC cable conduit that combines excellent aging resistance and flame retardant properties. Summary of the Invention

[0005] To address the shortcomings of polyvinyl chloride (PVC) cable conduits in possessing both excellent aging resistance and flame retardant properties, this application provides a fire-resistant PVC material, its preparation method, and a cable conduit.

[0006] In a first aspect, this application provides a fire-retardant polyvinyl chloride material, employing the following technical solution:

[0007] A fire-retardant polyvinyl chloride material comprises the following raw materials in parts by weight: 90-110 parts polyvinyl chloride, 10-20 parts compatibilizer, 8-15 parts ammonium polyphosphate and 5-8 parts anti-UV aging additive, wherein the anti-UV aging additive is a mixture of N,N"-bis(2,2,6,6-tetramethyl-4-piperidinyl)-1,6-hexanediamine and metal hydroxide.

[0008] Ammonium polyphosphate is an intumescent flame retardant that uses acid, carbon, and gas sources. It is non-toxic, odorless, does not produce corrosive gases, has low hygroscopicity, and high thermal stability.

[0009] The flame retardant mechanism of ammonium polyphosphate lies in the fact that after ammonium polyphosphate is heated and dehydrated, it generates a strong dehydrating agent of polyphosphate. The strong dehydrating agent of polyphosphate promotes the dehydration of organic matter surface to generate carbides. In addition, the generated non-volatile phosphorus oxides and polyphosphate cover the substrate surface, thereby achieving a flame retardant effect by isolating air.

[0010] Furthermore, because ammonium polyphosphate contains nitrogen, its thermal decomposition releases gases such as N2 and NH3. These gases are not easily combustible, thus blocking the oxygen supply and achieving a synergistic effect in flame retardancy. Simultaneously, its synergistic effect gives this flame retardant not only excellent flame retardant properties but also characteristics such as low smoke production, no toxic gas generation, and self-extinguishing properties.

[0011] However, because ammonium polyphosphate has a certain degree of weak acidity, and N,N"-bis(2,2,6,6-tetramethyl-4-piperidinyl)-1,6-hexanediamine is a hindered phenolic anti-UV aging agent, the effectiveness of hindered phenolic anti-UV aging agents is easily deteriorated in acidic environments, resulting in a significant decrease in the UV aging resistance of fire-retardant polyvinyl chloride materials.

[0012] Since metal hydroxides contain hydroxide ions, when metal hydroxides are added to anti-UV aging additives, the hydroxide ions in the metal hydroxides can neutralize excess acid radical ions, effectively improving the effect of acidic environment on the anti-UV aging performance of N,N"-bis(2,2,6,6-tetramethyl-4-piperidinyl)-1,6-hexanediamine.

[0013] Furthermore, the metal cations in metal hydroxides can promote the cross-linking of polyphosphoric acid to form a carbon layer structure with better thermal insulation properties. Simultaneously, the metal cations can improve the thermal stability of polyvinyl chloride (PVC) materials and reduce their maximum heat release rate. Moreover, the combustion of metal hydroxides can release non-flammable water vapor, thereby cooling the solid phase and providing a flame-retardant effect.

[0014] Preferably, the metal hydroxide contains several of the following: titanium dioxide nanotubes, zinc ions, magnesium ions, aluminum ions, and carbonate ions.

[0015] Preferably, the metal hydroxide contains titanium dioxide nanotubes, zinc ions, magnesium ions, aluminum ions, and carbonate ions.

[0016] Titanium dioxide nanotubes have high refractive index and high photoactivity. Moreover, since the electronic structure of titanium dioxide nanotubes consists of conduction bands formed by valence electron bands and empty orbitals, when they are irradiated with ultraviolet light, the ultraviolet light will release energy in the form of heat or fluorescence.

[0017] In addition, titanium dioxide nanotubes can provide skeletal support for the char formation process of the system during the thermal degradation of polymers, which is conducive to the formation of a more stable and dense char layer structure, enhances the barrier effect of the expanded char layer on polymers, heat sources and oxygen, delays the further combustion process of polymers, and improves the flame retardant effect of the expansion barrier system.

[0018] When the metal hydroxide also contains zinc, magnesium, and aluminum ions, a layered inorganic trimetallic layered double hydroxide-doped titanium dioxide nanotube structure will form within it. When the metal hydroxide burns, the free water between the layered double hydroxides decomposes thermally, carrying away some heat. During continuous heating, carbonate ions decompose into carbon dioxide, which escapes along with water vapor, carrying away heat and diluting the oxygen concentration. Furthermore, these metal ions can improve the thermal stability of polyvinyl chloride (PVC) and reduce the heat release rate, indirectly improving its flame-retardant properties.

[0019] Furthermore, due to the presence of the layered inorganic trimetallic hydrotalcite structure, N,N"-bis(2,2,6,6-tetramethyl-4-piperidinyl)-1,6-hexanediamine molecules can be introduced into the interlayer of hydrotalcite, effectively increasing the stability of organic molecules and indirectly improving the UV aging resistance of fire-retardant PVC. Moreover, hydrotalcite containing magnesium, zinc, and aluminum also possesses UV shielding and UV absorption properties, further enhancing the UV aging resistance of fire-retardant PVC.

[0020] Preferably, the method for preparing the metal hydroxide includes the following steps:

[0021] S1. Mix titanium dioxide nanotubes, zinc nitrate, magnesium nitrate, and aluminum nitrate, and then add water to prepare a metal salt solution;

[0022] S2. Heat water to 70-80℃, then gradually add metal salt solution and sodium hydroxide-sodium carbonate aqueous solution, stir and mix, crystallize at 90-100℃ for 24-48h, and finally cool, filter and dry to obtain metal hydroxide.

[0023] When crystallization is performed at the temperature in S2, the formation of metal hydroxides can be faster and more stable.

[0024] Preferably, the mass ratio of the titanium dioxide nanotubes, zinc nitrate, magnesium nitrate, and aluminum nitrate is (1.2-1.6):(0.4-0.8):1:1.

[0025] When titanium dioxide nanotubes, zinc nitrate, magnesium nitrate, and aluminum nitrate are used in the above-mentioned mass ratio, the prepared metal hydroxide has a better effect on improving the flame retardant properties and UV aging resistance of fire-retardant polyvinyl chloride.

[0026] Preferably, the mass ratio of N,N"-bis(2,2,6,6-tetramethyl-4-piperidinyl)-1,6-hexanediamine to metal hydroxide is (2-4):1.

[0027] When N,N"-bis(2,2,6,6-tetramethyl-4-piperidinyl)-1,6-hexanediamine and metal hydroxide are prepared in the above mass ratio, the resulting fire-retardant polyvinyl chloride has better flame retardant properties and UV aging resistance.

[0028] Preferably, the fire-retardant polyvinyl chloride material further includes 1-2 parts of aminotrimethylene phosphoric acid.

[0029] Aminotrimethylene phosphoric acid is a nitrogen-containing phosphoric acid with a strong complexing ability for metal cations. Therefore, it can combine with metal cations precipitated from metal hydroxides to form aminotrimethylene phosphate, thereby improving the thermal stability of fire-retardant PVC while simultaneously providing synergistic flame retardancy with nitrogen and phosphorus, and reducing the impact of free metal ions on the fire-retardant PVC. Furthermore, because the amount of aminotrimethylene phosphoric acid added is relatively small, its effect on the pH value of fire-retardant PVC is relatively minimal.

[0030] Preferably, the compatibilizer is a mixture of silane coupling agent and titanate coupling agent, and the mass ratio of silane coupling agent to titanate coupling agent is (1-3):1.

[0031] Because metal hydroxides contain titanium dioxide, and titanates are actually alkoxides of titanium, titanates can be more stably attached to metal hydroxides, effectively reducing the possibility of physical loss or extraction of titanates. Furthermore, the organic groups in silane coupling agents can be loaded onto titanates, thereby effectively preventing the physical migration or volatilization loss of organic groups.

[0032] When titanate coupling agents and silane coupling agents are used in combination, the compatibility between the components in fire-retardant PVC and the PVC matrix is ​​better, thereby further improving the flame retardant properties and UV aging resistance of fire-retardant PVC.

[0033] Secondly, this application provides a method for preparing a fire-retardant polyvinyl chloride material, employing the following technical solution:

[0034] A method for preparing a fire-resistant polyvinyl chloride material includes the following steps:

[0035] Polyvinyl chloride, compatibilizer, ammonium polyphosphate and anti-UV aging additives are mixed and stirred, and then extruded and granulated to obtain fire-retardant polyvinyl chloride material.

[0036] Thirdly, this application provides a cable sheath, which adopts the following technical solution:

[0037] A cable sheath made of the aforementioned fire-resistant polyvinyl chloride material.

[0038] In summary, this application has the following beneficial effects:

[0039] 1. Because ammonium polyphosphate has a certain degree of weak acidity, and N,N"-bis(2,2,6,6-tetramethyl-4-piperidinyl)-1,6-hexanediamine is a hindered phenolic anti-UV aging agent, the effectiveness of hindered phenolic anti-UV aging agents is easily deteriorated in acidic environments, which leads to a significant decrease in the UV aging resistance of fire-retardant polyvinyl chloride materials.

[0040] Since metal hydroxides contain hydroxide ions, when metal hydroxides are added to anti-UV aging additives, the hydroxide ions in the metal hydroxides can neutralize excess acid radical ions, effectively improving the effect of acidic environment on the anti-UV aging performance of N,N"-bis(2,2,6,6-tetramethyl-4-piperidinyl)-1,6-hexanediamine.

[0041] 2. The metal cations in metal hydroxides can promote the cross-linking of polyphosphoric acid to form a carbon layer structure with better thermal insulation properties. At the same time, the metal cations can also improve the thermal stability of polyvinyl chloride (PVC) materials and reduce the maximum heat release rate of PVC materials. Moreover, the combustion of metal hydroxides can release non-flammable water vapor, thereby cooling the solid phase and playing a flame-retardant role.

[0042] 3. Titanium dioxide nanotubes can provide skeletal support for the char formation process of the system during the thermal degradation of polymers, which is conducive to the formation of a more stable and dense char layer structure, enhances the barrier effect of the expanded char layer on polymers, heat sources and oxygen, delays the further combustion process of polymers, and improves the flame retardant effect of the expansion system.

[0043] 4. When the metal hydroxide also contains zinc, magnesium, and aluminum ions, a layered inorganic trimetallic hydrotalcite-doped titanium dioxide nanotube structure will form within the metal hydroxide. When the metal hydroxide burns, the free water between the hydrotalcite layers decomposes thermally, carrying away some heat. During continuous heating, carbonate ions decompose into carbon dioxide, which escapes along with water vapor, carrying away heat and simultaneously diluting the oxygen concentration. Furthermore, these metal ions can improve the thermal stability of polyvinyl chloride (PVC) and reduce the heat release rate, indirectly improving the flame retardant properties of PVC.

[0044] 5. Due to the presence of the layered inorganic trimetallic hydrotalcite structure, N,N"-bis(2,2,6,6-tetramethyl-4-piperidinyl)-1,6-hexanediamine molecules can be introduced into the interlayer of hydrotalcite, effectively increasing the stability of organic molecules and indirectly improving the UV aging resistance of fire-retardant PVC. Furthermore, hydrotalcite containing magnesium, zinc, and aluminum also possesses UV shielding and UV absorption properties, further enhancing the UV aging resistance of fire-retardant PVC.

[0045] 6. Aminotrimethylene phosphoric acid is a nitrogen-containing phosphoric acid, and it has a strong complexing ability for metal cations. Therefore, aminotrimethylene phosphoric acid can combine with the metal cations precipitated in metal hydroxides to form aminotrimethylene phosphate, thereby improving the thermal stability of fire-retardant PVC while simultaneously achieving nitrogen-phosphorus synergistic flame retardancy and reducing the impact of free metal ions on fire-retardant PVC. Detailed Implementation

[0046] The present application will be further described in detail below with reference to Examples 1-18 and Comparative Examples 1-3.

[0047] raw material

[0048] Polyvinyl chloride (PVC) CAS: 9002-86-2; Ammonium polyphosphate CAS: 68333-79-9; N,N"-Bis(2,2,6,6-Tetramethyl-4-piperidinyl)-1,6-hexanediamine CAS: 61260-55-7; Titanium dioxide nanotubes model JK-R0734; Zinc nitrate CAS: 10196-18-6; Magnesium nitrate CAS: 10377-60-3; Aluminum nitrate CAS: 13473-90-0; Sodium hydroxide CAS: 1310-73-2; Sodium carbonate CAS: 497-19-8; Aminotrimethylene phosphate CAS: 6419-19-8; Silane coupling agent model KH-151; Titanate coupling agent model NXH-501.

[0049] Example

[0050] Example 1

[0051] A fire-retardant polyvinyl chloride is prepared by mixing 100 kg of polyvinyl chloride, 15 kg of silane coupling agent, 12 kg of ammonium polyphosphate and 6 kg of anti-UV aging additive at a stirring speed of 15 r / min for 30 min, and then adding it to a twin-screw extruder for co-extrusion granulation.

[0052] The extruder operating conditions are as follows: feeding section 190℃, compression section 185℃, melting section 180℃, metering section 15℃, die section 195℃, and screw speed 120r / min.

[0053] The UV aging inhibitor is a mixture of N,N"-bis(2,2,6,6-tetramethyl-4-piperidinyl)-1,6-hexanediamine and metal hydroxide, with a mass ratio of N,N"-bis(2,2,6,6-tetramethyl-4-piperidinyl)-1,6-hexanediamine to metal hydroxide of 3:1.

[0054] The preparation method of metal hydroxide includes the following steps:

[0055] S1. Mix titanium dioxide nanotubes, zinc nitrate, magnesium nitrate and aluminum nitrate in a mass ratio of 1.4:0.6:1:1, and then add water twice the total mass to prepare a metal salt aqueous solution.

[0056] S2. Mix sodium hydroxide and sodium bicarbonate in a mass ratio of 3:3:1.4:0.6:1:1 for sodium hydroxide, sodium bicarbonate, titanium dioxide nanotubes, zinc nitrate, magnesium nitrate and aluminum nitrate; then add twice the total mass of water to prepare a sodium hydroxide-sodium carbonate aqueous solution.

[0057] The water was then heated to 75℃ (70-80℃ is suitable), and then the aqueous solution of metal salt and the aqueous solution of sodium hydroxide-sodium carbonate were gradually added dropwise. The mixture was stirred at 15r / min for 20min, and then crystallized at 95℃ (90-100℃ is suitable) for 36h (24-48h is suitable). Finally, the mixture was cooled, filtered, dried and ground to obtain a metal hydroxide with a particle size of 800 mesh.

[0058] Example 2-3

[0059] The difference from Example 1 is that the amount of each component added to the fire-retardant polyvinyl chloride is different, as shown in Table 1.

[0060] Table 1. Dosage of each component added to fire-retardant polyvinyl chloride in Examples 1-3 (kg)

[0061]

[0062] Examples 4-5

[0063] The difference from Example 1 is that the mass ratio of N,N"-bis(2,2,6,6-tetramethyl-4-piperidinyl)-1,6-hexanediamine to metal hydroxide is different, as shown in Table 2.

[0064] Table 2. Mass ratio of each component in the anti-UV aging additive in Examples 1 and 4-5

[0065]

[0066] Example 6

[0067] The difference from Example 1 is that no titanium dioxide nanotubes are added to the metal hydroxide.

[0068] Example 7

[0069] The difference from Example 1 is that zinc nitrate is not added to the metal hydroxide.

[0070] Example 8

[0071] The difference from Example 1 is that magnesium nitrate is not added to the metal hydroxide.

[0072] Example 9

[0073] The difference from Example 1 is that aluminum nitrate is not added to the metal hydroxide.

[0074] Examples 10-11

[0075] The difference from Example 1 is that the mass ratio of titanium dioxide nanotubes, zinc nitrate, magnesium nitrate, and aluminum nitrate in the metal hydroxide is different, as shown in Table 3.

[0076] Table 3. Mass ratio of each component in Examples 1 and 10-11

[0077] Titanium dioxide nanoparticles Zinc nitrate Magnesium nitrate Aluminum nitrate Example 1 1.4 0.6 1 1 Example 10 1.2 0.8 1 1 Example 11 1.6 0.4 1 1

[0078] Example 12

[0079] The difference from Example 1 is that 1.5 kg of aminotrimethylene phosphoric acid is added to the fire-retardant polyvinyl chloride.

[0080] Example 13

[0081] The difference from Example 12 is that 2 kg of aminotrimethylene phosphoric acid was added to the fire-retardant polyvinyl chloride.

[0082] Example 14

[0083] The difference from Example 12 is that 1 kg of aminotrimethylene phosphoric acid was added to the fire-retardant polyvinyl chloride.

[0084] Example 15

[0085] The difference from Example 12 is that the silane coupling agent is replaced with the same amount of titanate coupling agent.

[0086] Example 16

[0087] The difference from Example 12 is that the silane coupling agent is replaced with a mixture of silane coupling agent and titanate coupling agent in the same amount, and the mass ratio of silane coupling agent to titanate coupling agent is 1:1.

[0088] Example 17

[0089] The difference from Example 16 is that the mass ratio of silane coupling agent to titanate coupling agent is 2:1.

[0090] Example 18

[0091] The difference from Example 16 is that the mass ratio of silane coupling agent to titanate coupling agent is 3:1.

[0092] Comparative Example

[0093] Comparative Example 1

[0094] A polyvinyl chloride (PVC) is prepared by adding 100 kg of PVC to a twin-screw extruder for blending, extrusion, and granulation.

[0095] The extruder operating conditions are as follows: feeding section 190℃, compression section 185℃, melting section 180℃, metering section 15℃, die section 195℃, and screw speed 120r / min.

[0096] Comparative Example 2

[0097] The difference from Example 1 is that no metal hydroxide is added to the anti-UV aging additive.

[0098] Comparative Example 3

[0099] The difference from Example 1 is that ammonium polyphosphate is not added to the fire-retardant polyvinyl chloride, and metal hydroxides are not added to the anti-UV aging additive.

[0100] Application Examples

[0101] Application Examples 1-18

[0102] A cable sheath made of polyvinyl chloride as described in Examples 1-18.

[0103] Application of comparative examples

[0104] Application Comparative Examples 1-3

[0105] A cable sheath made of polyvinyl chloride in comparative proportions 1-3.

[0106] Performance testing

[0107] Detection methods

[0108] I. Flame retardant performance test

[0109] Three 10cm samples were taken from each of the application examples 1-18 and the comparative examples 1-3. Then, referring to GB / T2406-93 "Test Method for Burning Performance of Plastics - Oxygen Index Method", the igniter was inserted into the polyvinyl chloride sheath, and then the oxygen content was adjusted. If the burning time was greater than 180s, the oxygen content was reduced; if the burning time was less than 160s, the oxygen content was increased. Finally, the average value of the oxygen content was taken as the oxygen index.

[0110] II. UV Aging Resistance Test

[0111] Referring to GB / T16422.3-1997UV "Laboratory Light Source Exposure Test Method for Plastics" Part 3: Fluorescent Ultraviolet Lamps, six 10cm long samples were cut from the sheaths of Application Examples 1-20 and Comparative Examples 1-5 respectively.

[0112] Three samples were subjected to tensile testing according to GB / T1040-1992 "Test Method for Tensile Properties of Plastics", and the tensile strength before aging was measured. The other three samples were placed in an ultraviolet aging chamber for 6 days of aging treatment at an ultraviolet intensity of 210 W / m. 2 The aging temperature is 60℃, and then a tensile test is performed to measure the tensile strength after aging. Finally, the aging retention rate is calculated and the average value is taken.

[0113] Aging retention rate = tensile strength after aging / tensile strength before aging * 100%.

[0114] Test results: The test results of Application Examples 1-18 and Application Comparative Examples 1-3 are shown in Table 5.

[0115] Table 5 shows the test results of application examples 1-18 and comparative examples 1-3.

[0116]

[0117]

[0118] Referring to Application Examples 1-3 and Application Comparative Example 1, and in conjunction with Table 5, it can be seen that, compared to Comparative Example 1, the flame retardant oxygen index and aging retention rate of Examples 1-3 are significantly improved. This indicates that the addition of ammonium polyphosphate and anti-UV aging additives can effectively improve the flame retardant properties and UV aging resistance of polyvinyl chloride.

[0119] Compared to Application Example 1, the flame retardant oxygen index and aging retention rate of Application Examples 2-3 are slightly lower. This indicates that when the components in the fire-retardant PVC are in the same mass ratio as in Application Example 1, the fire-retardant PVC has better flame retardant properties and UV aging resistance.

[0120] Referring to Comparative Examples 1-3 and Table 5, it can be seen that compared to Comparative Example 1, Comparative Example 3 shows a slight improvement in the oxygen index of its flame retardant properties and a significant improvement in its aging retention rate. This is because, in addition to its compatibility with the components of fire-retardant PVC, the silane coupling agent also has a certain flame retardant performance enhancement effect. Furthermore, N,N"-bis(2,2,6,6-tetramethyl-4-piperidinyl)-1,6-hexanediamine exhibits extremely excellent UV aging resistance enhancement effects.

[0121] Compared to Comparative Example 3, Comparative Example 2 showed a significant improvement in the oxygen index of its flame-retardant properties, but its aging retention rate actually decreased slightly. The reason for this is that while ammonium polyphosphate has an excellent flame-retardant performance enhancement effect, it is weakly acidic. N,N"-bis(2,2,6,6-tetramethyl-4-piperidinyl)-1,6-hexanediamine is a hindered phenolic UV aging inhibitor, and the effectiveness of hindered phenolic UV aging inhibitors deteriorates easily in acidic environments, leading to a significant decrease in the UV aging resistance of the fire-retardant polyvinyl chloride material.

[0122] Compared to Comparative Example 2, Application Example 1 showed a significant improvement in both the flame retardant oxygen index and aging retention rate. This is because the metal hydroxide contains hydroxide ions. When metal hydroxide is added to the anti-UV aging additive, the hydroxide ions in the metal hydroxide can neutralize excess acid radical ions, effectively improving the effect of the acidic environment on the anti-UV aging performance of N,N"-bis(2,2,6,6-tetramethyl-4-piperidinyl)-1,6-hexanediamine.

[0123] Furthermore, the metal cations in metal hydroxides can promote the cross-linking of polyphosphoric acid to form a carbon layer structure with better thermal insulation properties. Simultaneously, the metal cations can improve the thermal stability of polyvinyl chloride (PVC) materials and reduce their maximum heat release rate. Moreover, the combustion of metal hydroxides can release non-flammable water vapor, thereby cooling the solid phase and providing a flame-retardant effect.

[0124] Based on Application Examples 1, 4-5, and Table 5, it can be seen that, compared to Application Example 1, the oxygen index of the flame retardant performance in Application Example 4 is slightly improved, but the aging retention rate of Application Example 4 is slightly decreased. Compared to Application Example 1, the oxygen index of the flame retardant performance in Application Example 4 is slightly decreased, but the aging retention rate of Application Example 5 is slightly improved.

[0125] Therefore, taking all factors into consideration, when the components in the anti-UV aging additive are used in the mass ratio of Application Example 1, the fire-retardant polyvinyl chloride has superior flame retardant properties and UV aging resistance.

[0126] Based on Application Examples 1, 6-9, and Table 5, it can be seen that compared to Application Example 1, the flame retardant oxygen index and aging retention rate of Application Examples 6-9 are slightly lower. This indicates that when the raw material of the metal hydroxide is a mixture of titanium dioxide nanotubes, zinc nitrate, magnesium nitrate, and aluminum nitrate, the fire-retardant polyvinyl chloride has better flame retardant properties and UV aging resistance.

[0127] The reason for this is that titanium dioxide nanotubes can provide skeletal support for the char formation process of the system during the thermal degradation of polymers, which is conducive to the formation of a more stable and dense char layer structure, enhances the barrier effect of the expanded char layer on polymers, heat sources and oxygen, delays the further combustion process of polymers, and improves the flame retardant effect of the expansion system.

[0128] When the metal hydroxide also contains zinc, magnesium, and aluminum ions, a layered inorganic trimetallic layered double hydroxide-doped titanium dioxide nanotube structure will form within it. When the metal hydroxide burns, the free water between the layered double hydroxides decomposes thermally, carrying away some heat. During continuous heating, carbonate ions decompose into carbon dioxide, which escapes along with water vapor, carrying away heat and diluting the oxygen concentration. Furthermore, these metal ions can improve the thermal stability of polyvinyl chloride (PVC) and reduce the heat release rate, indirectly improving its flame-retardant properties.

[0129] Furthermore, due to the presence of the layered inorganic trimetallic hydrotalcite structure, N,N"-bis(2,2,6,6-tetramethyl-4-piperidinyl)-1,6-hexanediamine molecules can be introduced into the interlayer of hydrotalcite, effectively increasing the stability of organic molecules and indirectly improving the UV aging resistance of fire-retardant PVC. Moreover, hydrotalcite containing magnesium, zinc, and aluminum also possesses UV shielding and UV absorption properties, further enhancing the UV aging resistance of fire-retardant PVC.

[0130] Based on Application Example 1, Application Examples 10-11 and Table 5, it can be seen that, compared with Application Example 1, the flame retardant oxygen index and aging retention rate of Application Examples 10-11 are slightly lower. This indicates that when the components of the metal hydroxide are in the same mass ratio as in Application Example 1, the fire-retardant polyvinyl chloride has better flame retardant properties and UV aging resistance.

[0131] Combining Application Examples 1, Application Examples 12-14, and Table 5, it can be seen that compared with Application Example 1, the flame retardant performance, oxygen index, and aging retention rate of Application Example 12 are significantly improved. The reason for this is that aminotrimethylene phosphate has a strong complexing ability for metal cations. Therefore, aminotrimethylene phosphate can combine with the metal cations precipitated in metal hydroxides to form aminotrimethylene phosphate, thereby improving the thermal stability of fire-retardant PVC while simultaneously achieving nitrogen-phosphorus synergistic flame retardancy and reducing the impact of free metal ions on the UV aging resistance of fire-retardant PVC.

[0132] Compared to Application Example 12, the flame retardant oxygen index of Application Example 13 remained basically unchanged, but the aging retention rate of Application Example 13 decreased significantly. The reason for this is that the excessive addition of aminotrimethylene phosphoric acid will cause the fire-retardant polyvinyl chloride system to become too acidic, thereby significantly affecting the UV aging resistance of N,N"-bis(2,2,6,6-tetramethyl-4-piperidinyl)-1,6-hexanediamine.

[0133] Compared to Application Example 12, the flame retardant performance, oxygen index, and aging retention rate of Application Example 14 are significantly lower, indicating that the amount of aminotrimethylene phosphoric acid added in Application Example 14 is relatively small.

[0134] Based on Application Examples 12, 15-18 and Table 5, it can be seen that compared with Application Example 16, the flame retardant oxygen index and aging retention rate of Application Examples 12 and 15 are significantly reduced. This indicates that the mixed use of silane coupling agent and titanate coupling agent can significantly improve the flame retardant performance and UV aging resistance of fire-retardant polyvinyl chloride.

[0135] In Application Examples 16-18, the flame retardant oxygen index and aging retention rate of Application Example 17 are relatively high. This indicates that when the mass ratio of silane coupling agent to titanate coupling agent is used as in Application Example 17, the fire-retardant polyvinyl chloride has better flame retardant properties and UV aging resistance.

[0136] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A fire retardant polyvinyl chloride material, characterized by, The fireproof PVC material comprises the following raw materials by weight: 90-110 parts of PVC, 10-20 parts of a compatibilizer, 8-15 parts of ammonium polyphosphate, and 5-8 parts of an anti-UV aging additive, which is a mixture of N,N'-bis(2,2,6,6-tetramethyl-4-piperidyl)-1,6-hexanediamine and a metal hydroxide; The metal hydroxide contains titanium dioxide nanotubes, zinc ions, magnesium ions, aluminum ions, and carbonate ions; The preparation method of the metal hydroxide comprises the following steps: S1, mixing titanium dioxide nanotubes, zinc nitrate, magnesium nitrate, and aluminum nitrate, and then adding water to prepare a metal salt solution; S2, heating water to 70-80℃, then gradually adding the metal salt solution and a sodium hydroxide-sodium carbonate aqueous solution, and then stirring and mixing, crystallizing at 90-100℃ for 24-48h, and finally cooling, filtering, and drying to obtain the metal hydroxide; The mass ratio of the titanium dioxide nanotubes, zinc nitrate, magnesium nitrate, and aluminum nitrate is (1.2-1.6):(0.4-0.8):1:1; The mass ratio of the N,N'-bis(2,2,6,6-tetramethyl-4-piperidyl)-1,6-hexanediamine and the metal hydroxide is (2-4):

1.

2. The fire resistant polyvinyl chloride material according to claim 1, wherein: The fireproof PVC material further comprises 1-2 parts of aminotri(methylene)phosphonic acid.

3. The fire resistant polyvinyl chloride material of claim 1, wherein: The compatibilizer is a mixture of a silane coupling agent and a titanate coupling agent, and the mass ratio of the silane coupling agent and the titanate coupling agent is (1-3):

1.

4. A method for producing the fireproof polyvinyl chloride material according to any one of claims 1 to 3, characterized by, The method comprises the following steps: Mixing PVC, a compatibilizer, ammonium polyphosphate, and an anti-UV aging additive, and then extruding and granulating to obtain the fireproof PVC material.

5. A cable jacket characterized by: The cable sheath is made of the fireproof PVC material according to any one of claims 1-3.

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