Preparation process of high-temperature-resistant flame-retardant chloroprene rubber composite material

Abstract

The application discloses a preparation process of high-temperature-resistant and flame-retardant chloroprene rubber composite material and relates to the technical field of chloroprene rubber production. The raw materials are composed of 80-100 parts of chloroprene rubber, 40-60 parts of magnesium hydroxide, 15-25 parts of decabromodiphenyl ethane, 6-10 parts of antimony trioxide, 4-6 parts of zinc oxide, 3-5 parts of magnesium oxide, 0.6-1 part of accelerator NA-22, 1-2 parts of stearic acid, 0.8-1.5 parts of antioxidant 4010NA, 0.8-1.5 parts of antioxidant RD, 30-50 parts of carbon black N330, 8-15 parts of plasticizer DOTP and 5-8 parts of synergistic intermediate. The synergistic antioxidant effect formed by adding the synergistic intermediate into the chloroprene rubber composite material raw materials delays the thermal oxygen degradation of the polymer chain, the micronized wax migrates to the surface to form a physical barrier to effectively isolate oxygen, so that the requirements of high-temperature and high-reliability application scenarios such as automobile engine compartments can be met.

Description

Technical Field

[0001] This invention relates to the field of chloroprene rubber production technology, and more specifically, to a preparation process for a high-temperature resistant and flame-retardant chloroprene rubber composite material. Background Technology

[0002] Chloroprene rubber is widely used in the automotive, electronics, and chemical industries due to its excellent oil resistance, weather resistance, and mechanical properties. It is one of the key basic materials, especially in the seals and pipelines in the automotive engine compartment. However, the automotive engine compartment is a typical high-temperature, high-oxygen, and harsh service environment. It is under continuous high temperature for a long time, accompanied by mechanical vibration and oil and gas corrosion, which puts extremely high requirements on the heat aging resistance of chloroprene rubber composites.

[0003] However, conventional chloroprene rubber composites currently on the market usually rely on single or simply compounded chemical antioxidants to resist thermo-oxidative aging. Although such antioxidant systems can delay material aging in the short term, the antioxidants are easily consumed rapidly under long-term high-temperature action, leading to severe thermo-oxidative degradation of the polymer chains, resulting in problems of low practicality and functionality. Summary of the Invention

[0004] In view of the problems in related technologies, this invention proposes a preparation process for high-temperature resistant and flame-retardant chloroprene rubber composite materials to overcome the above-mentioned technical problems existing in the existing related technologies.

[0005] Therefore, the specific technical solution adopted by the present invention is as follows:

[0006] A high-temperature flame-retardant chloroprene rubber composite material comprises the following raw materials in parts by weight: 80-100 parts chloroprene rubber, 40-60 parts magnesium hydroxide, 15-25 parts decabromodiphenyl ethane, 6-10 parts antimony trioxide, 4-6 parts zinc oxide, 3-5 parts magnesium oxide, 0.6-1 part accelerator NA-22, 1-2 parts stearic acid, 0.8-1.5 parts antioxidant 4010NA, 0.8-1.5 parts antioxidant RD, 30-50 parts carbon black N330, 8-15 parts plasticizer DOTP, and 5-8 parts synergistic intermediates;

[0007] The collaborative intermediate is made by the following steps:

[0008] Step 1: Add antioxidant 445 and micronized wax to a high-speed mixer and mix to obtain a premix.

[0009] Step 2: Slowly add the plasticizer DOTP while maintaining stirring in a high-speed mixer. Increase the speed and continue stirring to form a uniform paste-like pre-dispersion between the premix and the plasticizer DOTP, thus obtaining a synergistic intermediate.

[0010] As a preferred embodiment, the mass ratio of the antioxidant 445 and the micronized wax used in step 1 is 1:3, the stirring mixing speed is 200-300 r / min, and the stirring time is 5 minutes.

[0011] As a preferred embodiment, the mass ratio of the plasticizer DOTP and the antioxidant 445 in step 2 is 8:1, the stirring speed is 800-1000 r / min, and the stirring time is 20-30 minutes.

[0012] A preparation process of a high-temperature-resistant flame-retardant chloroprene rubber composite material includes the following preparation steps:

[0013] The preparation process includes the following preparation steps:

[0014] S1, the following raw materials are weighed by mass fraction: wherein the raw materials are composed of 80-100 parts of chloroprene rubber, 40-60 parts of magnesium hydroxide, 15-25 parts of decabromodiphenyl ethane, 6-10 parts of antimony trioxide, 4-6 parts of zinc oxide, 3-5 parts of magnesium oxide, 0.6-1 part of accelerator NA-22, 1-2 parts of stearic acid, 0.8-1.5 parts of antioxidant 4010NA, 0.8-1.5 parts of antioxidant RD, 30-50 parts of carbon black N330, 8-15 parts of plasticizer DOTP, and 5-8 parts of synergistic intermediate;

[0015] S2, the magnesium hydroxide and the antimony trioxide are dried in an oven to remove moisture, and the chloroprene rubber is plasticized in an internal mixer, then the synergistic intermediate, the magnesium oxide, the stearic acid, the antioxidant 4010NA, and the antioxidant RD are sequentially added and mixed, after the mixing is completed, the carbon black N330, the magnesium hydroxide, the decabromodiphenyl ethane, the antimony trioxide, and the plasticizer DOTP are added, and the mixing is continued until the temperature reaches 110-120℃, then the rubber compound is discharged, and the rubber compound is obtained;

[0016] S3, the rubber compound is cooled by being thinly passed through an open mill, then is sheeted in a triangle bag, is parked and cooled for 4 hours, then is rolled by an open mill, and then the zinc oxide and the accelerator NA-22 are sequentially added, the left and right knives are cut, and the triangle bag is punched 5-8 times, then the rubber compound is sheeted with a large roller gap after being uniformly mixed, and the final rubber compound is obtained;

[0017] S4, the final rubber compound is placed in a mold of a flat vulcanizing machine for vulcanization molding, the vulcanized product is placed in a blast oven for secondary vulcanization for 4 hours, then is taken out after being cooled with the oven, and a high-temperature-resistant flame-retardant chloroprene rubber composite material is obtained.

[0018] As a preferred embodiment, the drying temperature of the magnesium hydroxide and the antimony trioxide in the oven in S2 is 100-110℃, the drying time is 2 hours, and the mixing time of the synergistic intermediate, the magnesium oxide, the stearic acid, the antioxidant 4010NA, and the antioxidant RD is 2 minutes.

[0019] As a preferred embodiment, the temperature of the thin heat dissipation cooling in S3 is cooled to 50 DEG C, and the parameter setting of the mixing roll mill of the mixing rubber is that the roll temperature is 40+ / -5 DEG C, and the roll gap is 1.0-1.5 mm.

[0020] As a preferred embodiment, the mixing uniformity in S3 is adjusted to increase the roll gap, and the roll gap is adjusted to 2.0-3.0 mm.

[0021] As a preferred embodiment, the temperature of the two-stage vulcanization in S4 is 150+ / -2 DEG C.

[0022] As a preferred embodiment, the temperature of the two-stage vulcanization in S4 is 150+ / -2 DEG C.

[0023] The beneficial effects of the present application are:

[0024] 1. The present application adds a synergistic intermediate to the raw material of the chlorobutyl rubber composite material, wherein the antioxidant 445 forms a synergistic antioxidant effect with the antioxidants 4010NA and RD in the basic formula, delays the thermal oxidative degradation of the polymer chain, and the micronized wax migrates to the surface to form a physical barrier, effectively isolates oxygen, improves the long-term heat aging performance of the chlorobutyl rubber composite material, and better meets the requirements of high temperature and high reliability application scenarios such as automobile engine compartment;

[0025] 2. The micronized wax in the synergistic intermediate migrates to the surface of the material to form a dense physical barrier layer to effectively isolate oxygen and heat invasion, and forms a "physical+chemical" double protection mechanism with the internal chemical antioxidant system, synergistically reduces the consumption rate of the antioxidant, and prolongs the service life of the material in a high temperature environment.

[0026] 3. The synergistic intermediate of the present application uses DOTP as a carrier and perfectly integrates with the whole system, disperses the antioxidants 445, micronized wax and other solid functional additives into fine and uniform paste by high shear in advance, forms a pre-dispersed masterbatch to improve the subsequent distribution uniformity, avoids the performance short board caused by poor local dispersion, and enhances the material processing stability and performance consistency. BRIEF DESCRIPTION OF DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0028] Figure 1A flow chart of a preparation process of a high-temperature-resistant and flame-retardant chloroprene rubber composite material according to an embodiment of the present application. DETAILED DESCRIPTION

[0029] To further illustrate the embodiments, the present application provides accompanying drawings, which are part of the disclosure of the present application, mainly used to illustrate the embodiments, and can be used to explain the operating principle of the embodiments in conjunction with the related description of the specification. Those skilled in the art should understand other possible implementations and advantages of the present application by referring to these contents. The components in the drawings are not drawn to scale, and similar component symbols are generally used to represent similar components.

[0030] According to an embodiment of the present application, a preparation process of a high-temperature-resistant and flame-retardant chloroprene rubber composite material is provided.

[0031] The present application will be further described in conjunction with the accompanying drawings and specific embodiments:

[0032] Embodiment 1

[0033] A high-temperature-resistant and flame-retardant chloroprene rubber composite material according to an embodiment of the present application comprises the following raw materials by mass fraction: wherein the raw materials are composed of 80-100 parts of chloroprene rubber, 40-60 parts of magnesium hydroxide, 15-25 parts of decabromodiphenyl ethane, 6-10 parts of antimony trioxide, 4-6 parts of zinc oxide, 3-5 parts of magnesium oxide, 0.6-1 part of accelerator NA-22, 1-2 parts of stearic acid, 0.8-1.5 parts of antioxidant 4010NA, 0.8-1.5 parts of antioxidant RD, 30-50 parts of carbon black N330, 8-15 parts of plasticizer DOTP, and 5-8 parts of synergistic intermediate.

[0034] A preparation method of a high-temperature-resistant and flame-retardant chloroprene rubber composite material comprises the following preparation steps:

[0035] Firstly, the following raw materials are weighed by mass fraction: wherein the raw materials are composed of 80-100 parts of chloroprene rubber, 40-60 parts of magnesium hydroxide, 15-25 parts of decabromodiphenyl ethane, 6-10 parts of antimony trioxide, 4-6 parts of zinc oxide, 3-5 parts of magnesium oxide, 0.6-1 part of accelerator NA-22, 1-2 parts of stearic acid, 0.8-1.5 parts of antioxidant 4010NA, 0.8-1.5 parts of antioxidant RD, 30-50 parts of carbon black N330, 8-15 parts of plasticizer DOTP, and 5-8 parts of synergistic intermediate.

[0036] Step 2: Place magnesium hydroxide and antimony trioxide in an oven and dry at 100-110℃ for 2 hours to remove moisture. Put chloroprene rubber into a mixer and plasticize for 30-60 seconds. Then add the synergistic intermediate, magnesium oxide, stearic acid, antioxidant 4010NA, and antioxidant RD in sequence and mix for 2 minutes. Then add carbon black N330, magnesium hydroxide, decabromodiphenyl ethane, antimony trioxide, and plasticizer DOTP and mix until the temperature reaches 110-120℃. Then discharge the rubber to obtain the compound.

[0037] The third step is to heat the rubber compound on a two-roll mill and cool it to 50°C. Then, make triangular wraps to form sheets and let it cool for 4 hours. After that, set the roller temperature to 40±5°C and the roller gap to 1.0-1.5mm so that the rubber compound wraps around the roller. Then, add zinc oxide and accelerator NA-22 in sequence, cut with left and right cutters, and make triangular wraps 5-8 times. After mixing evenly, increase the roller gap to 2.0-3.0mm and sheet the final rubber compound.

[0038] Step 4: Place the final compounded rubber into the mold of the flat vulcanizing machine, set the vulcanizing temperature of the flat vulcanizing machine to 160±2℃, the vulcanizing pressure to 12-15MPa, and the vulcanizing time to be based on the T90 value measured by the vulcanizer plus 2 minutes for vulcanization molding. Place the vulcanized product into a forced-air drying oven and perform secondary vulcanization at 150±2℃ for 4 hours. After cooling in the oven, remove the product to obtain a high-temperature resistant and flame-retardant chloroprene rubber composite material.

[0039] The collaborative intermediate is made by the following steps:

[0040] Step 1: Add antioxidant 445 and micronized wax to a high-speed mixer and stir at 200-300 r / min for 5 minutes to obtain a premix.

[0041] Step 2: While stirring in a high-speed mixer, slowly add the plasticizer DOTP, increase the speed to 800-1000 r / min, and stir for 20-30 minutes to form a uniform paste-like pre-dispersion between the premix and the plasticizer DOTP, thus obtaining a synergistic intermediate.

[0042] The mass ratio of antioxidant 445 to micronized wax used is 1:3, and the mass ratio of plasticizer DOTP to antioxidant 445 is 8:1. The micronized wax is micronized polyethylene wax with a particle size D50 of 8.0µm.

[0043] Example 2:

[0044] A high-temperature resistant and flame-retardant chloroprene rubber composite material, the specific process and preparation flow are as follows:

[0045] The first step is to weigh the following raw materials according to the following mass percentages: the raw materials consist of 80 parts chloroprene rubber, 40 parts magnesium hydroxide, 15 parts decabromodiphenyl ethane, 6 parts antimony trioxide, 4 parts zinc oxide, 3 parts magnesium oxide, 0.6 parts accelerator NA-22, 1 part stearic acid, 0.8 parts antioxidant 4010NA, 0.8 parts antioxidant RD, 30 parts carbon black N330, 8 parts plasticizer DOTP, and 5 parts synergistic intermediates;

[0046] Step 2: Place 40 parts magnesium hydroxide and 6 parts antimony trioxide in an oven and dry at 110°C for 2 hours to remove moisture. Put 80 parts chloroprene rubber into a mixer and plasticize for 45 seconds. Then add 5 parts synergistic intermediate, 3 parts magnesium oxide, 1 part stearic acid, 0.8 parts antioxidant 4010NA, and 0.8 parts antioxidant RD in sequence and mix for 2 minutes. Then add 30 parts carbon black N330, 40 parts magnesium hydroxide, 15 parts decabromodiphenyl ethane, 6 parts antimony trioxide, and 8 parts plasticizer DOTP and mix until the temperature reaches 110°C. Then discharge the rubber to obtain the compound.

[0047] The third step is to heat the rubber compound on a two-roll mill and cool it to 50°C. Then, make triangular wraps to form sheets and let it cool for 4 hours. After that, set the roller temperature to 45°C and the roller gap to 1.0 mm so that the rubber compound wraps around the roller. Then, add 4 parts of zinc oxide and 0.6 parts of accelerator NA-22 in sequence. Cut the rubber compound with left and right cutters and make triangular wraps 8 times. After mixing evenly, increase the roller gap to 2.5 mm and sheet the rubber compound to obtain the final rubber compound.

[0048] Step 4: Place the final compounded rubber into the mold of the flat vulcanizing machine, set the vulcanizing temperature of the flat vulcanizing machine to 160℃, the vulcanizing pressure to 15MPa, and the vulcanizing time to be based on the T90 value measured by the vulcanizer plus 2 minutes for vulcanization molding. Place the vulcanized product into a forced-air drying oven and perform secondary vulcanization at 150℃ for 4 hours. After cooling in the oven, remove the product to obtain a high-temperature resistant and flame-retardant chloroprene rubber composite material.

[0049] The collaborative intermediate is made by the following steps:

[0050] Step 1: Add antioxidant 445 and micronized wax to a high-speed mixer and stir at 250 r / min for 5 minutes to obtain a premix, wherein the mass ratio of antioxidant 445 to micronized wax is 1:3.

[0051] Step 2: Slowly add plasticizer DOTP while maintaining stirring in a high-speed mixer, increase the speed to 1000 r / min and stir for 30 minutes to form a uniform paste-like pre-dispersion between the premix and plasticizer DOTP, thus obtaining a synergistic intermediate. The mass ratio of plasticizer DOTP to antioxidant 445 is 8:1, and the micronized wax is micronized polyethylene wax with a particle size D50 of 8.0 µm.

[0052] Example 3:

[0053] A high-temperature resistant and flame-retardant chloroprene rubber composite material, the specific process and preparation flow are as follows:

[0054] The first step is to weigh the following raw materials according to the following mass percentages: the raw materials consist of 100 parts chloroprene rubber, 60 parts magnesium hydroxide, 25 parts decabromodiphenyl ethane, 10 parts antimony trioxide, 6 parts zinc oxide, 5 parts magnesium oxide, 1 part accelerator NA-22, 2 parts stearic acid, 1.5 parts antioxidant 4010NA, 1.5 parts antioxidant RD, 50 parts carbon black N330, 15 parts plasticizer DOTP, and 8 parts synergistic intermediates;

[0055] Step 2: Place 60 parts magnesium hydroxide and 10 parts antimony trioxide in an oven and dry at 110°C for 2 hours to remove moisture. Put 100 parts chloroprene rubber into a mixer and plasticize for 45 seconds. Then add 8 parts synergistic intermediate, 5 parts magnesium oxide, 2 parts stearic acid, 1.5 parts antioxidant 4010NA, and 1.5 parts antioxidant RD in sequence and mix for 2 minutes. Then add 50 parts carbon black N330, 60 parts magnesium hydroxide, 25 parts decabromodiphenyl ethane, 10 parts antimony trioxide, and 15 parts plasticizer DOTP and mix until the temperature reaches 110°C. Then discharge the rubber to obtain the compound.

[0056] The third step is to heat the rubber compound on a two-roll mill and cool it to 50°C. Then, make triangular wraps to form sheets and let it cool for 4 hours. After that, set the roller temperature to 45°C and the roller gap to 1.0 mm so that the rubber compound wraps around the roller. Then, add 6 parts of zinc oxide and 1 part of accelerator NA-22 in sequence. Cut the rubber compound with left and right cutters and make triangular wraps 8 times. After mixing evenly, increase the roller gap to 2.5 mm and sheet the rubber compound to obtain the final rubber compound.

[0057] Step 4: Place the final compounded rubber into the mold of the flat vulcanizing machine, set the vulcanizing temperature of the flat vulcanizing machine to 160℃, the vulcanizing pressure to 15MPa, and the vulcanizing time to be based on the T90 value measured by the vulcanizer plus 2 minutes for vulcanization molding. Place the vulcanized product into a forced-air drying oven and perform secondary vulcanization at 150℃ for 4 hours. After cooling in the oven, remove the product to obtain a high-temperature resistant and flame-retardant chloroprene rubber composite material.

[0058] The collaborative intermediate is made by the following steps:

[0059] Step 1: Add antioxidant 445 and micronized wax to a high-speed mixer and stir at 250 r / min for 5 minutes to obtain a premix, wherein the mass ratio of antioxidant 445 to micronized wax is 1:3.

[0060] Step 2: Slowly add plasticizer DOTP while maintaining stirring in a high-speed mixer, increase the speed to 1000 r / min and stir for 30 minutes to form a uniform paste-like pre-dispersion between the premix and plasticizer DOTP, thus obtaining a synergistic intermediate. The mass ratio of plasticizer DOTP to antioxidant 445 is 8:1, and the micronized wax is micronized polyethylene wax with a particle size D50 of 8.0 µm.

[0061] Comparative Example 1:

[0062] By removing the synergistic intermediate from Example 2, a high-temperature resistant and flame-retardant chloroprene rubber composite material was prepared according to the following steps:

[0063] A high-temperature resistant and flame-retardant chloroprene rubber composite material, the specific process and preparation flow are as follows:

[0064] The first step is to weigh the following raw materials according to their mass percentages: 80 parts chloroprene rubber, 40 parts magnesium hydroxide, 15 parts decabromodiphenyl ethane, 6 parts antimony trioxide, 4 parts zinc oxide, 3 parts magnesium oxide, 0.6 parts accelerator NA-22, 1 part stearic acid, 0.8 parts antioxidant 4010NA, 0.8 parts antioxidant RD, 30 parts carbon black N330, and 8 parts plasticizer DOTP;

[0065] Step 2: Place 40 parts magnesium hydroxide and 6 parts antimony trioxide in an oven and dry at 110°C for 2 hours to remove moisture. Put 80 parts chloroprene rubber into a mixer and plasticize for 45 seconds. Then add 3 parts magnesium oxide, 1 part stearic acid, 0.8 parts antioxidant 4010NA, and 0.8 parts antioxidant RD in sequence and mix for 2 minutes. Then add 30 parts carbon black N330, 40 parts magnesium hydroxide, 15 parts decabromodiphenyl ethane, 6 parts antimony trioxide, and 8 parts plasticizer DOTP and mix until the temperature reaches 110°C. Then discharge the rubber to obtain the compound.

[0066] The third step is to heat the rubber compound on a two-roll mill and cool it to 50°C. Then, make triangular wraps to form sheets and let it cool for 4 hours. After that, set the roller temperature to 45°C and the roller gap to 1.0 mm so that the rubber compound wraps around the roller. Then, add 4 parts of zinc oxide and 0.6 parts of accelerator NA-22 in sequence. Cut the rubber compound with left and right cutters and make triangular wraps 8 times. After mixing evenly, increase the roller gap to 2.5 mm and sheet the rubber compound to obtain the final rubber compound.

[0067] Step 4: Place the final rubber compound into the mold of the flat vulcanizing machine, set the vulcanizing temperature of the flat vulcanizing machine to 160℃, the vulcanizing pressure to 15MPa, and the vulcanizing time to be based on the T90 value measured by the vulcanizer + 2 minutes for vulcanization molding. Place the vulcanized product into a forced-air drying oven and perform secondary vulcanization at 150℃ for 4 hours. After cooling in the oven, take it out to obtain a high-temperature resistant flame-retardant chloroprene rubber composite material.

[0068] Comparative Example 2:

[0069] The synergistic intermediate in Example 3 was removed, and the high-temperature flame-retardant chloroprene rubber composite material was prepared according to the following steps:

[0070] The first step is to weigh the following raw materials according to their mass percentages: 100 parts chloroprene rubber, 60 parts magnesium hydroxide, 25 parts decabromodiphenyl ethane, 10 parts antimony trioxide, 6 parts zinc oxide, 5 parts magnesium oxide, 1 part accelerator NA-22, 2 parts stearic acid, 1.5 parts antioxidant 4010NA, 1.5 parts antioxidant RD, 50 parts carbon black N330, and 15 parts plasticizer DOTP;

[0071] Step 2: Place 60 parts magnesium hydroxide and 10 parts antimony trioxide in an oven and dry at 110°C for 2 hours to remove moisture. Put 100 parts chloroprene rubber into a mixer and plasticize for 45 seconds. Then add 5 parts magnesium oxide, 2 parts stearic acid, 1.5 parts antioxidant 4010NA, and 1.5 parts antioxidant RD in sequence and mix for 2 minutes. Then add 50 parts carbon black N330, 60 parts magnesium hydroxide, 25 parts decabromodiphenyl ethane, 10 parts antimony trioxide, and 15 parts plasticizer DOTP and mix until the temperature reaches 110°C. Then discharge the rubber to obtain the compound.

[0072] The third step is to heat the rubber compound on a two-roll mill and cool it to 50°C. Then, make triangular wraps to form sheets and let it cool for 4 hours. After that, set the roller temperature to 45°C and the roller gap to 1.0 mm so that the rubber compound wraps around the roller. Then, add 6 parts of zinc oxide and 1 part of accelerator NA-22 in sequence. Cut the rubber compound with left and right cutters and make triangular wraps 8 times. After mixing evenly, increase the roller gap to 2.5 mm and sheet the rubber compound to obtain the final rubber compound.

[0073] Step 4: Place the final rubber compound into the mold of the flat vulcanizing machine, set the vulcanizing temperature of the flat vulcanizing machine to 160℃, the vulcanizing pressure to 15MPa, and the vulcanizing time to be based on the T90 value measured by the vulcanizer + 2 minutes for vulcanization molding. Place the vulcanized product into a forced-air drying oven and perform secondary vulcanization at 150℃ for 4 hours. After cooling in the oven, take it out to obtain a high-temperature resistant flame-retardant chloroprene rubber composite material.

[0074] Experimental Example 1:

[0075] The high-temperature flame-retardant neoprene rubber composites obtained in Examples 2 and 3 and Comparative Examples 1 and 2 were subjected to performance tests, including tensile strength and elongation at break tests, hardness tests, hot air aging tests, and vertical ignition rating tests. The test results are shown in Tables 1 and 2.

[0076] Table 1: Initial Physical and Mechanical Properties and Flame Retardancy Test Table

[0077]

[0078] For the tensile strength and elongation at break tests, the vulcanized rubber compounds obtained in Comparative Examples 1 and 2, as well as Examples 2 and 3, were cut into dumbbell-shaped specimens using a standard cutter. The specimens were clamped in the upper and lower clamps of a universal testing machine and stretched at a uniform speed of 500 mm / min until they broke. The maximum force value and the length change rate at break were recorded. Five specimens were tested for each formulation and the average value was taken.

[0079] The hardness test was performed by stacking the vulcanized rubber sheets obtained in Comparative Examples 1 and 2 and Examples 2 and 3 into a flat test piece with a thickness of 6 mm. The indenter was pressed vertically and quickly onto the surface of the sample using a Shore A hardness tester. After the pointer stabilized, the scale value was read to obtain the Shore A hardness. The test was performed 5 times at different positions on the sample surface and the average value was taken.

[0080] The oxygen index test involved preparing strip-shaped samples with dimensions of 100mm × 6.5mm × 3mm from the rubber compounds obtained in Comparative Examples 1 and 2, as well as Examples 2 and 3. The samples were vertically fixed in a combustion chamber, and a nitrogen + oxygen mixture was introduced into the chamber with an upward flow. The top of the sample was attempted to be ignited starting from an oxygen concentration of 25%, and its combustion behavior was observed. The oxygen concentration was adjusted using the "lifting method" based on whether the sample continued to burn for more than 3 minutes or the burning length exceeded 50mm. The lowest oxygen concentration percentage was calculated to obtain the limiting oxygen index (LOI). Five samples were tested for each formulation, and the average value was taken.

[0081] The vertical burning test involved preparing strip-shaped samples with dimensions of 125mm × 13mm × 3mm from the rubber compounds obtained in Comparative Examples 1 and 2, as well as Examples 2 and 3. The lower end of the sample was burned with a Bunsen burner flame for 10 seconds. After removing the flame, the flaming burning time of the sample was recorded. If the sample extinguished, it was burned again for 10 seconds. The flaming burning time and the non-flaming burning time were recorded again after removing the flame. The grade was determined based on the sum of the two flaming burning times and whether the degreased cotton was ignited.

[0082] Table 1 shows that, compared with the unadded Comparative Examples 1 and 2, Examples 2 and 3 with the addition of the synergistic intermediate showed a slight increase in initial tensile strength, elongation, and hardness, but this increase was not significant. This indicates that the main function of the synergistic intermediate was not to significantly improve the initial strength, but rather to act as a functional additive. In terms of flame retardant performance, the oxygen index (LOI) of the examples was about 3 percentage points higher than that of the comparative examples, and the vertical burning rating was improved from V-1 to V-0. This suggests that the micronized wax in the synergistic intermediate may have promoted the formation of a denser char layer during combustion, producing a synergistic effect with the main flame retardant system and further improving the flame retardant efficiency.

[0083] Table 2: Thermal Aging Performance Test Table

[0084]

[0085] The hot air aging test involved preparing the initial samples for tensile strength and hardness testing obtained from Comparative Examples 1 and 2, as well as Examples 2 and 3, and measuring the initial values. The samples were then suspended in a preheated oven at 150°C for 72 hours. After removal, the samples were cooled at standard laboratory temperature for 16 hours. The tensile strength, elongation at break, and hardness of the samples were measured again. The performance change rate was calculated by (post-aging value - pre-aging value) / pre-aging value × 100%.

[0086] Table 2 shows that Comparative Examples 1 and 2 exhibited severely degraded performance, with tensile strength decreasing by over 20% and elongation plummeting by 30%, becoming harder and more brittle. This indicates that the materials have aged and lost their usability under prolonged high temperatures. Examples 2 and 3, on the other hand, maintained good performance, with tensile strength decreasing by approximately 8%, elongation decreasing by approximately 16%, and hardness slightly increasing. The antioxidant 445 in the synergistic intermediate, together with antioxidants 4010NA and RD in the base formulation, formed a synergistic antioxidant effect, delaying the thermo-oxidative degradation of the polymer chains. Simultaneously, the physical barrier formed by the migration of micronized wax to the surface effectively isolated oxygen, thus constituting a dual chemical and physical protection, enhancing the material's performance. It has a long service life with high temperature resistance. After the antioxidant captures a free radical, it becomes a less active free radical. At this time, another antioxidant can react with this less active antioxidant free radical, regenerating it and restoring it to its active form, thus continuing to play a role and extending the effective life of the antioxidant system. Through the decomposition of hydrogen peroxide by RD, 445 and 4010NA synergistically terminate the growth of free radical chains, forming a three-dimensional, multi-layered chemical protection system that synergistically resists thermo-oxidative aging. After vulcanization, the micronized wax gradually migrates to the surface of the rubber product, forming a dense and continuous protective film to isolate oxygen and block the impact of heat.

[0087] In summary, this invention adds a synergistic intermediate to the chloroprene rubber composite material raw material. The antioxidant 445 therein forms a strong synergistic antioxidant effect with the antioxidants 4010NA and RD in the basic formulation, which delays the thermo-oxidative degradation of the polymer chain. At the same time, the micronized wax migrates to the surface to form a physical barrier, effectively isolating oxygen and improving the long-term heat aging resistance of the chloroprene rubber composite material, so that it can better meet the requirements of high-temperature and high-reliability application scenarios such as automotive engine compartments.

[0088] By migrating the micronized wax in the synergistic intermediate to the material surface to form a dense physical barrier layer, it effectively isolates oxygen and heat from intrusion. At the same time, it forms a "physical + chemical" dual protection mechanism with the internal chemical anti-aging system, synergistically reducing the consumption rate of anti-aging agents and extending the service life of materials in high-temperature environments.

[0089] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A high-temperature resistant, flame-retardant chloroprene rubber composite material, characterized in that, The raw materials include the following parts by weight: 80-100 parts chloroprene rubber, 40-60 parts magnesium hydroxide, 15-25 parts decabromodiphenyl ethane, 6-10 parts antimony trioxide, 4-6 parts zinc oxide, 3-5 parts magnesium oxide, 0.6-1 part accelerator NA-22, 1-2 parts stearic acid, 0.8-1.5 parts antioxidant 4010NA, 0.8-1.5 parts antioxidant RD, 30-50 parts carbon black N330, 8-15 parts plasticizer DOTP, and 5-8 parts synergistic intermediates; The preparation method of this high-temperature resistant and flame-retardant chloroprene rubber composite material is as follows: S1. Weigh the following raw materials by mass: the raw materials consist of 80-100 parts chloroprene rubber, 40-60 parts magnesium hydroxide, 15-25 parts decabromodiphenyl ethane, 6-10 parts antimony trioxide, 4-6 parts zinc oxide, 3-5 parts magnesium oxide, 0.6-1 parts accelerator NA-22, 1-2 parts stearic acid, 0.8-1.5 parts antioxidant 4010NA, 0.8-1.5 parts antioxidant RD, 30-50 parts carbon black N330, 8-15 parts plasticizer DOTP, and 5-8 parts synergistic intermediates; The collaborative intermediate is made by the following steps: Step 1: Add antioxidant 445 and micronized wax in a mass ratio of 1:3 into a high-speed mixer and mix to obtain a premix. Step 2: Slowly add plasticizer DOTP while maintaining stirring in a high-speed mixer. Increase the speed and continue stirring to form a uniform paste-like pre-dispersion between the premix and plasticizer DOTP, thus obtaining a synergistic intermediate. The mass ratio of plasticizer DOTP to antioxidant 445 is 8:

1. In step 1, the stirring speed of the antioxidant 445 and the micronized wax is 200-300 r / min and the stirring time is 5 minutes. In step 2, the stirring speed is 800-1000 r / min and the stirring time is 20-30 minutes. S2. Place magnesium hydroxide and antimony trioxide in an oven to dry to remove moisture. Put chloroprene rubber into a mixer for plasticizing. Then, add the synergistic intermediate, magnesium oxide, stearic acid, antioxidant 4010NA, and antioxidant RD in sequence and mix. After mixing, add carbon black N330, magnesium hydroxide, decabromodiphenyl ethane, antimony trioxide, and plasticizer DOTP. Mix until the temperature reaches 110-120℃ and then discharge the rubber to obtain the compound. The drying temperature of magnesium hydroxide and antimony trioxide in S2 in the oven is 100-110℃, the drying time is 2 hours, and the mixing time of the synergistic intermediate, magnesium oxide, stearic acid, antioxidant 4010NA and antioxidant RD is 2 minutes. S3. After cooling the rubber compound on a two-roll mill, roll it out in a triangular shape and let it cool for 4 hours. Then, roll the rubber compound through the two-roll mill to wrap the rollers. Then, add zinc oxide and accelerator NA-22 in sequence. Cut the rubber compound with left and right cutters and roll it in a triangular shape 5-8 times. After mixing evenly, adjust the roller gap and roll it out to obtain the final rubber compound. S4. Place the final rubber compound into the mold of the flat vulcanizing machine for vulcanization molding. Place the vulcanized product into the blower oven for secondary vulcanization for 4 hours. After cooling in the oven, take it out to obtain high temperature resistant flame retardant chloroprene rubber composite material.

2. The high-temperature resistant and flame-retardant chloroprene rubber composite material according to claim 1, characterized in that, The temperature of the thin-walled heat dissipation cooling in S3 is 50℃, and the parameters of the mixing rubber roll open mill are set as roll temperature 40±5℃ and roll gap 1.0-1.5mm.

3. The high-temperature resistant and flame-retardant chloroprene rubber composite material according to claim 1, characterized in that, After the mixture in step S3 is homogenized, the roller gap is increased to produce the sheet, wherein the roller gap is increased to 2.0-3.0 mm.

4. The high-temperature resistant and flame-retardant chloroprene rubber composite material according to claim 1, characterized in that, The S4 flat vulcanizing machine has a vulcanization temperature of 160±2℃, a vulcanization pressure of 12-15MPa, and a vulcanization time of 2 minutes based on the T90 value measured by the vulcanizer.

5. The high-temperature resistant and flame-retardant chloroprene rubber composite material according to claim 1, characterized in that, The temperature for the second stage of vulcanization in S4 is 150±2℃.

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