A rubber fireproof block, a preparation process thereof and a cable conduit wall-penetration sealing system

Abstract

The present application relates to a kind of rubber fireproof block and its preparation process and cable conduit wall sealing system, the formula of the fireproof block includes the following mass parts of ingredients: solid ethylene-propylene-diene rubber 75-85 parts, liquid ethylene-propylene-diene rubber 90-105 parts, nano silicon micro powder 18-22 parts, nano silicon carbide ceramic powder 23-27 parts, polytetrafluoroethylene micro powder 7-9 parts, calcined clay 16-20 parts, low temperature ceramic powder 18-22 parts, basic white carbon black 12-17 parts.The fireproof block of the present application has the advantages of good sealing effect, quick assembly, high flexibility, slow temperature conduction, rapid ceramization (rapidly block fire spread) and the like.

Description

Technical Field

[0001] This invention belongs to the field of flame retardancy, specifically relating to a rubber fireproof block, its preparation process, and a cable duct wall-penetrating sealing system using the fireproof block. Background Technology

[0002] The elastic materials used in existing pipeline sealing systems have the following fire-resistant issues:

[0003] 1. Difference in compression set;

[0004] These materials require high compression set to maintain long-term sealing performance. However, due to their high filler content and low glue content, existing materials on the market have relatively high compression set.

[0005] 2. Fast heat conduction.

[0006] Currently, similar materials on the market, after being ablated at 1500℃ for 2.5 hours, have a surface temperature on the back side of the ablated surface exceeding 200℃, indicating excessively rapid heat conduction.

[0007] 3. Slow ceramization speed.

[0008] Currently, all elastic materials rely mainly on the ceramicization of rubber fillers to block and delay flame erosion or corrosion under continuous flame ablation. However, the ceramicization speed of similar materials on the market is too slow. Often, the material has been burned through before a ceramic layer is formed, and open flames have appeared on the back of the ablated surface.

[0009] 4. High ceramization temperature,

[0010] Another important indicator for preventing flame ablation is the ceramization temperature. The lower the ceramization temperature, the sooner the ablation prevention function can be achieved. However, the ceramization temperature of existing materials is too high. Summary of the Invention

[0011] To address the problems of high ceramization temperature and slow speed in existing technologies, this invention provides a rubber fireproof block, its preparation process, and a cable duct wall-penetrating sealing system.

[0012] The technical solution of the present invention is as follows:

[0013] A rubber fireproof block, characterized in that its formula comprises the following components in parts by weight:

[0014] Solid EPDM rubber 75-85 parts, liquid EPDM rubber 90-105 parts, nano-silicon powder 18-22 parts, nano-silicon carbide ceramic powder 23-27 parts, polytetrafluoroethylene powder 7-9 parts, calcined clay 16-20 parts, low-temperature ceramic powder 18-22 parts, and alkaline silica 12-17 parts.

[0015] Preferably, it also includes the following components in parts by weight: 7-9 parts phenolic FRP, 0.3-0.7 parts silicone 69, and 3-5 parts polyethylene glycol.

[0016] Preferably, it also includes the following components in parts by weight: 40-60 parts aluminum hydroxide and / or magnesium hydroxide, 12-18 parts iron oxide red, and 6-10 parts zinc oxide.

[0017] Preferably, the product also includes the following components in parts by weight: 7-9 parts erucamide, 7-9 parts internal release agent, 8-10 parts low molecular weight polypropylene wax, 0.5-0.7 parts 4,4′-dithiodimorpholine (DTDM), 0.5-0.7 parts insoluble sulfur, 0.4-0.6 parts N-cyclohexyl-2-benzothiazole sulfenamide (CZ), 0.5-0.7 parts zinc di-n-butyl dithiocarbamate (BZ), 0.5-0.7 parts tetramethylthiuram disulfide (TT), 0.1-0.3 parts 2,4-di-tert-butyl peroxide (odorless DCP), 0.03-0.07 parts triallyl isocyanurate (TAIC), 14-18 parts halogen-free flame retardant 6003, 18-20 parts halogen-free flame retardant 8006, and 1-3 parts stearic acid.

[0018] Preferably, the formulation of the low-temperature ceramic powder includes: low-temperature glass powder, low-temperature ceramic crystal phase powder, and low-temperature sintering aid;

[0019] The formulation of the low-temperature glass powder includes: 30-60 parts SiO2, 10-30 parts B2O3, 10-30 parts alkali metal or alkaline earth oxides, 5-20 parts Al2O3, and modifier; the low-temperature ceramic phase powder is an alumina-based powder combined with glass additives.

[0020] The aforementioned manufacturing process for a rubber fireproof block is characterized by comprising the following steps:

[0021] 1) Rubber mixing process,

[0022] The process includes, in sequence: ingredient preparation, mixing in an internal mixer, sheeting out on a two-roll mill, storage, sulfur addition on a two-roll mill, sheeting out on a two-roll mill, and storage.

[0023] 2) Vulcanization process,

[0024] The process includes, in sequence: preforming of rubber compound, molding, venting, vulcanization, and demolding.

[0025] Preferably, in step 1), the discharge temperature of the internal mixer is 100℃-120℃, and the discharge temperature of the open mill is 70℃-90℃.

[0026] Preferably, the vulcanization mold temperature in step 2) is 155℃±5℃. After loading the rubber material obtained in step 1), the air is vented, the mold is pressurized and depressurized, and the pressure and temperature are maintained at 18MPA±2MPA for 900 seconds before demolding.

[0027] The cable conduit wall-penetrating sealing system using the aforementioned rubber fireproof blocks is characterized in that a plurality of the fireproof blocks are sealed in the wall hole, and the pipeline passes through the fireproof blocks and is in close contact with the fireproof blocks.

[0028] The preferred fireproof blocks include those with dimensions of 20*20*60mm, 30*30*60mm, 40*40*60mm, 50*50*60mm, 60*60*60mm, and 90*90*60mm (length*width*depth).

[0029] The technical effects of this invention are as follows:

[0030] This invention provides a novel fireproof block for sealing and sealing through walls of rubber pipes, characterized by rapid ceramization, low ceramization temperature, and the ability to quickly block the spread of fire. It also includes the preparation process of the fireproof block and a cable duct wall-penetrating sealing system utilizing this fireproof block, enabling rapid assembly and effective fire prevention. Through its formulation design, this material also achieves excellent sealing performance (elasticity allowing for compression during installation), rapid assembly (no need for cement, adhesives, or other fixation), high flexibility (perforation diameter and shape are prefabricated standard dimensions), and slow temperature conduction.

[0031] Specifically,

[0032] 1. Low ceramization temperature:

[0033] The working process of the ceramicized flame-retardant system of this invention:

[0034] It begins to decompose and release water of crystallization above 300℃, absorbing heat and cooling down.

[0035] It reaches its dehydration peak at 400℃-450℃ and synergistically retards flame retardants with aluminum hydroxide, magnesium hydroxide and other flame retardants.

[0036] The melting reaction begins at around 550℃.

[0037] When completely melted at 650℃, it can form a low-melting-point glassy substance, and together with the "alumina + magnesium oxide" decomposed from aluminum hydroxide and magnesium hydroxide, it forms a ceramic layer at around 680℃.

[0038] The ceramization temperature of this invention, around 680°C, is significantly lower than that of other materials.

[0039] The ceramicized flame-retardant system of this invention is mainly composed of aluminosilicate materials. Through the blending of nano-silicon powder, nano-silica ceramic powder, and low-temperature ceramic powder, a ceramicization temperature significantly lower than that of existing technologies is achieved. Nano-silicon carbide ceramic powder is used to enhance the strength, wear resistance, and high-temperature resistance of the compound, falling under the category of reinforcing fillers. Low-temperature ceramic powder is a filler that melts and crystallizes into a ceramicized fire-retardant layer when the product is heated, and thus belongs to the category of fire-retardant materials.

[0040] Mechanism of action of ceramic flame retardant system:

[0041] During the melting process, the ceramic flame-retardant system combines with the inorganic and organic decomposition products within the rubber vulcanization and filling system. Upon heating and melting, it forms a dense glassy body, gradually creating a ceramic-structured outer shell. This shell isolates oxygen, prevents further combustion, suppresses smoke and toxic volatiles, and reduces heat transfer, thereby providing functions such as sealing, bonding, flame retardancy, insulation, and protection.

[0042] It works synergistically with flame retardants to prevent fires and reduce losses. Furthermore, it isolates oxygen, thus significantly suppressing smoke and ember combustion, achieving a flame-retardant effect.

[0043] Specific features of the ceramicized flame-retardant system of this invention:

[0044] (1) Low temperature melting. The ceramic flame retardant system begins to melt at around 550°C. The melt is dense and glassy with a glossy appearance. After melting, it can be used as an adhesive and sealing material to seamlessly connect materials with different properties.

[0045] (2) High temperature resistance. Compared with traditional flame-retardant rubber materials, ceramic flame-retardant systems have a high durability temperature and can withstand more severe high-temperature environments.

[0046] (3) Insulation. The ceramic flame retardant system has good dielectric properties and resistance to electrical breakdown, and can achieve good application results in high and low voltage cables and electronic devices.

[0047] (4) Flame retardancy. When the ambient temperature is not high enough, the ceramic flame retardant system is flame retardant by the synergistic flame retardant. When the ambient temperature exceeds the working temperature of the synergistic flame retardant, it begins to melt. The melt isolates the flammable material from oxygen and thus achieves the flame retardant effect, preventing the spread of combustion.

[0048] (5) Acid and alkali resistance. Low-temperature ceramic powder has good resistance to acid and alkali and chemical corrosion. In addition, it also has the characteristics of weather resistance, water boiling resistance and ultraviolet radiation resistance.

[0049] 2. Slow heat conduction speed:

[0050] The material of this invention, by adding fillers with low thermal conductivity such as nano-silicon powder, nano-silicon carbide ceramic powder, polytetrafluoroethylene powder, and calcined clay ceramic powder, effectively reduces the heat transfer rate without affecting performance. In the test, after 3 hours of ablation, the surface temperature on the ablated side was below 150°C. Simultaneously, the use of synergistic flame retardants such as aluminum hydroxide, zinc oxide (which also functions as an activator), and iron oxide red acts as a heat sink within the rubber, rapidly transferring heat away and preventing heat accumulation, internal expansion, and thermal failure. This combination of fast and slow heat transfer ensures system stability and safety.

[0051] 3. Fast ceramization speed:

[0052] The material of this invention can be heated to 800°C in 20 minutes in an oxyacetylene flame, and can still maintain a certain thickness and good sealing after being ablated at 1500°C for 3 hours, indicating that the ceramization temperature is very fast and prevents the further spread of the flame.

[0053] Furthermore, this invention uses solid EPDM rubber as the main component of the rubber formulation, while liquid EPDM rubber, being liquid, is primarily used as a softening plasticizer. Generally, plasticizers are mostly oil-based and easily volatilize at high temperatures. Liquid EPDM rubber can not only replace plasticizers to achieve the same effect, but also, compared to other plasticizers, has better compatibility with solid EPDM rubber, a higher flash point, and can not only increase the filling amount of the rubber compound and prevent compounding agents from spraying out, but also increase the product's ignition point and make the system more stable.

[0054] This invention uses halogen-free flame retardant 6003 and halogen-free flame retardant 8006 together as synergistic flame retardants. While ensuring overall performance, the amount added can exceed that of existing technologies, effectively covering all temperature stages before ceramization.

[0055] The addition of nano-silicon powder, nano-silicon carbide ceramic powder, and ceramic powder in the stage before ceramization can effectively improve the initial heat resistance of the product while improving the processing performance and flowability of the adhesive. It also increases the product's structural density and strength, reduces material wear rate, and enhances erosion resistance.

[0056] Phenolic FRP primarily serves a reinforcing function. This formulation, designed for fire resistance and ceramicization, has a high filler ratio and low rubber content. Adding this material effectively increases strength without compromising fire resistance and heat resistance. However, the compounding process is somewhat unique because phenolic FRP has poor shear resistance and is prone to breakage. High-strength fiber-reinforced polymer / plastic (FRP) composites have high tensile strength; the tensile strength of FRP is significantly higher than that of steel bars, comparable to that of high-strength steel wire, and generally 2 to 10 times that of steel bars. It also features a low coefficient of thermal expansion, similar to that of concrete, corrosion resistance, fatigue resistance, insulation, heat insulation, and electromagnetic wave transmission. The blending of alkaline silica, silicon 69, and phenolic FRP results in low compression set.

[0057] This invention preferably uses silicon 69 and ethylene glycol as structure control agents. The structure problem of silica (SiO2) refers to the fact that due to the large number of silanol groups (Si-OH) on its surface, silica (SiO2) forms strong hydrogen bonds with rubber molecules during the mixing and storage of rubber (especially silicone rubber), constructing a three-dimensional network, leading to hardening of the rubber compound, decreased plasticity, and poor flowability. Using structure control agents can prevent this structure problem. Basic silica itself has relatively reduced structure, and it also solves the problems of slow vulcanization, interfered crosslinking, and low modulus caused by ordinary acid silica, while retaining its reinforcing properties. Attached Figure Description

[0058] Figure 1 This is a schematic diagram of the wall cross-section of the environment in which the cable duct wall-penetrating sealing system of Example 4 is used.

[0059] The labels in the diagram are listed below:

[0060] 1-Rubber block, 2-Pipeline, 3-Wall. Detailed Implementation

[0061] To better understand the present invention, the present invention will be further explained below with reference to specific embodiments.

[0062] Examples 1-3

[0063] Examples 1-3 illustrate a rubber fireproof block provided by the present invention. The formulations for each example are as follows:

[0064]

[0065] Low-temperature ceramic powder is a type of ceramic powder that can be densified at temperatures far below those of traditional ceramics (typically <1000℃, commonly 600–900℃). The low-temperature ceramic powder formulation used in this invention is as follows:

[0066] I. Core Components (Classified by System)

[0067] 1. Low-temperature glass powder

[0068] Basic systems: borosilicate (B2O3–SiO2), boroaluminosilicate, lithium borosilicate (LBS), lead borosilicate (low lead / lead-free).

[0069] Typical formulation: SiO2 (50%) + B2O3 (20%) + Na2O (or other alkali metal / alkaline earth oxides such as Li2O, K2O, CaO, BaO, 20%) + Al2O3 (5%) + small amount of modulators such as ZnO, ZrO2, TiO2, etc.

[0070] Function: With a low melting point (around 500-600℃), it softens and fills the gaps between particles, promoting densification, which is key to achieving low-temperature sintering.

[0071] 2. Low-temperature ceramic crystalline phase powder (main crystalline phase)

[0072] It uses alumina-based nano / ultrafine Al2O3, combined with glass additives, and can be sintered at 800–950℃.

[0073] Alternatively, lead zirconate titanate / niobate-based piezoelectric / ferroelectric ceramics such as PZT, PMN–PT, and NBT can be used, sintered at 850–950℃ after adding glass sintering depressant; or microwave dielectric ceramics such as Li–Nb–Ti and ZnO–B2O3; or low-temperature ceramics based on kaolin / feldspar / clay, mainly composed of feldspar, kaolin, and quartz, with the addition of flux (such as talc and spodumene), and fired at 800–1000℃.

[0074] 3. Low-temperature sintering aid (general purpose)

[0075] Oxides: Bi2O3, V2O5, CuO, ZnO, Li2CO3, Na2CO3, B2O3, etc.

[0076] Fluorides: LiF, NaF, CaF2 (strong fluxing agent, lowers sintering temperature).

[0077] Nanoparticles: nano ZrO2 and nano MgO, which promote the formation of necks in low-temperature sintering through high surface energy.

[0078] The preparation processes for each embodiment are as follows:

[0079] 1) Rubber mixing process,

[0080] The process includes, in sequence: ingredient preparation, mixing in an internal mixer, sheeting out on a two-roll mill, resting, sulfurizing on a two-roll mill, sheeting out on a two-roll mill – resting.

[0081] The discharge temperature of the internal mixer is 100℃-120℃, and the discharge temperature of the open mill is 70℃-90℃.

[0082] 2) Vulcanization process,

[0083] The process includes, in sequence: preforming of the rubber compound, molding, venting, vulcanization, and demolding.

[0084] The rubber fireproof block products of each embodiment were obtained by applying a temperature of 155℃±5℃*18PMA±2MPA*900S±30S.

[0085] After testing, all embodiments met the following results:

[0086] 1. Compression set properties:

[0087] The test method and standard are ASTM D395, compression deformation below 33% (100℃*70H, compression 15%).

[0088] 2. During the test, after 3 hours of ablation, the surface temperature on the back side of the ablation site was below 150℃.

[0089] 3. The oxyacetylene flame reaches 800℃ in 20 minutes, and after 3 hours of burning at 1500℃, it can still maintain a certain thickness, providing good sealing and quickly preventing the further spread of the flame.

[0090] (The ablation test in the above embodiments was conducted at the National Institute of Fire Protection. The test standard sample was a rubber wall. Temperature was measured on the outer back side, but ablation occurred on the inner side. The actual ceramicization progress could not be observed. However, based on the heat insulation effect and sample thickness, it can be known that the ceramicization speed must be very fast, and a complete ceramic layer can be formed within at least 20 minutes.)

[0091] Example 4

[0092] This embodiment describes a cable duct wall-penetrating sealing system using the product prepared in Example 1, such as... Figure 1 As shown, at the opening location where a pipe 2 or cable needs to pass through the wall 3, rubber blocks 1 of appropriate size and quantity are selected as needed, and the pipe 2 or cable passes through the rubber blocks 1. In this embodiment, the length, width, and depth dimensions of the rubber block 1 are 20*20*60mm, but different modules with lengths and widths of 20, 30, 40, 60, 90mm, etc., are also available, facilitating assembly and offering high flexibility. Due to the elasticity of the rubber block 1, it can achieve a good seal while also serving as a flame retardant and barrier.

[0093] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention in any other way. Any person skilled in the art may make changes or equivalent modifications based on the above-disclosed technical content. 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 content of the technical solution of the present invention shall still fall within the protection scope of the technical solution of the present invention.

Claims

1. A rubber fire block, characterized in that The formula includes the following ingredients in parts by weight: Solid EPDM rubber 75-85 parts, liquid EPDM rubber 90-105 parts, nano-silicon powder 18-22 parts, nano-silicon carbide ceramic powder 23-27 parts, polytetrafluoroethylene powder 7-9 parts, calcined clay 16-20 parts, low-temperature ceramic powder 18-22 parts, basic silica 12-17 parts, aluminum hydroxide and / or magnesium hydroxide 40-60 parts.

2. A fire block according to claim 1, characterised in that It also includes the following components in parts by weight: 7-9 parts phenolic FRP, 0.3-0.7 parts silicone 69, and 3-5 parts polyethylene glycol.

3. The fireproof block according to claim 1, characterized in that... It also includes the following components by weight: 12-18 parts iron oxide red and 6-10 parts zinc oxide.

4. The fireproof block according to claim 1, characterized in that... It also includes the following components in parts by weight: 7-9 parts erucamide, 7-9 parts internal release agent, 8-10 parts low molecular weight polypropylene wax, 3-5 parts polyethylene glycol, 0.5-0.7 parts 4,4′-dithiodimorpholine, 0.5-0.7 parts insoluble sulfur, 0.4-0.6 parts N-cyclohexyl-2-benzothiazole sulfenyl, 0.5-0.7 parts zinc di-n-butyl dithiocarbamate, 0.5-0.7 parts tetramethylthiuram disulfide, 0.1-0.3 parts 2,4-di-tert-butyl peroxide isopropylbenzene, and 0.03-0.07 parts triallyl isocyanuric acid.

5. The fireproof block according to claim 1, characterized in that... The formulation of the low-temperature ceramic powder includes: low-temperature glass powder, low-temperature ceramic crystal phase powder, and low-temperature sintering aid; The formulation of the low-temperature glass powder includes: 30-60 parts SiO2, 10-30 parts B2O3, 10-30 parts alkali metal or alkaline earth oxides, 5-20 parts Al2O3, and modifier; the low-temperature ceramic phase powder is an alumina-based powder combined with glass additives.

6. The preparation process of a rubber fireproof block according to any one of claims 1-5, characterized in that... Includes the following steps: 1) Rubber mixing process, The process includes, in sequence: ingredient preparation, mixing in an internal mixer, sheeting out on a two-roll mill, resting, sulfurizing on a two-roll mill, sheeting out on a two-roll mill, and resting. 2) Vulcanization process, The process includes, in sequence: preforming of rubber compound, molding, venting, vulcanization, and demolding.

7. The process according to claim 6, characterized in that... In step 1), the discharge temperature of the internal mixer is 100℃-120℃, and the discharge temperature of the open mill is 70℃-90℃.

8. The process according to claim 6, characterized in that... In step 2), the vulcanization mold temperature is 155℃±5℃. After loading the rubber material obtained in step 1), the air is vented, and the mold is pressurized and depressurized. Under a pressure of 18MPA±2MPA, the pressure and temperature are maintained for 900 seconds before demolding.

9. A cable duct wall-penetrating sealing system using any one of the rubber fireproof blocks described in claims 1-5, characterized in that... Several fireproof blocks are sealed in the wall holes, and pipelines pass through the fireproof blocks and are in close contact with the fireproof blocks.

10. The cable duct wall-penetrating sealing system according to claim 9, characterized in that... The fireproof blocks are available in sizes of 20*20*60mm, 30*30*60mm, 40*40*60mm, 50*50*60mm, 60*60*60mm, and 90*90*60mm (length*width*depth).

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