阅读说明：本技术 一种耐久性阻燃橡胶材料用改性剂及其制备方法、耐久性橡胶材料及其制备方法 (Modifier for durable flame-retardant rubber material, preparation method of modifier, durable rubber material and preparation method of durable rubber material ) 是由 谭莲影 杨瑞蒙 杨军 余海文 王雪飞 程志 谢竞慧 黄良平 吴玲玲 于 2021-09-18 设计创作，主要内容包括：本发明提供了一种耐久性阻燃橡胶材料用改性剂及其制备方法、耐久性橡胶材料及其制备方法,改性剂为3,4-二氨基-(1,1’-联苯)-3,5-二羧酸；橡胶材料的原料按重量份包括：生胶100份；改性剂1-5份；催化剂0.05-1份；补强填充剂30-50份；阻燃剂20-50份；防老剂6-12份；增塑剂11-32份；活性剂3-5份；硫化促进剂12-16份；本发明的耐久性阻燃橡胶材料具有优异的长期耐热氧、耐臭氧以及耐疲劳老化等性能,在静态与动态下皆具有优异的耐久性。(The invention provides a modifier for a durable flame-retardant rubber material and a preparation method thereof, and a durable rubber material and a preparation method thereof, wherein the modifier is 3, 4-diamino- (1, 1' -biphenyl) -3, 5-dicarboxylic acid; the rubber material comprises the following raw materials in parts by weight: 100 parts of raw rubber; 1-5 parts of a modifier; 0.05-1 part of catalyst; 30-50 parts of reinforcing filler; 20-50 parts of a flame retardant; 6-12 parts of an anti-aging agent; 11-32 parts of a plasticizer; 3-5 parts of an active agent; 12-16 parts of a vulcanization accelerator; the durable flame-retardant rubber material has excellent long-term thermal oxygen resistance, ozone resistance, fatigue aging resistance and other performances, and has excellent durability under static and dynamic conditions.)

1. A modifier for durable flame-retardant rubber materials is characterized in that the modifier is 3, 4-diamino- (1, 1' -biphenyl) -3, 5-dicarboxylic acid.

2. A preparation method of a modifier for durable flame-retardant rubber materials is characterized by adding 4-bromo-1, 2-phenylenediamine, 3, 5-dicarboxyphenylboronic acid, a modification catalyst and weak base into a solvent, evaporating the solvent after the reaction is finished, and drying to obtain the modifier.

3. The method for preparing the modifier for durable flame-retardant rubber material according to claim 2, wherein the molar ratio of the 4-bromo-1, 2-phenylenediamine, the 3, 5-dicarboxyphenylboronic acid, the modification catalyst, the weak base and the alcoholic solvent is (1.0): (1.1-1.5):(0.01-0.05): (1.5-3): (30-60).

4. The preparation method of the modifier for durable flame-retardant rubber material as claimed in claim 2, wherein the modification catalyst is palladium acetate, the weak base is carbonate, the solvent is an alcohol solvent, the reaction is a reflux reaction, and the solvent is evaporated by rotary evaporation.

5. The durable flame-retardant rubber material is characterized by comprising the following raw materials in parts by weight:

100 parts of raw rubber;

1-5 parts of a modifier;

0.05-1 part of catalyst;

30-50 parts of reinforcing filler;

20-50 parts of a flame retardant;

6-12 parts of an anti-aging agent;

11-32 parts of a plasticizer;

3-5 parts of an active agent;

5-9 parts of a vulcanization accelerator;

wherein the modifier is 3, 4-diamino- (1, 1' -biphenyl) -3, 5-dicarboxylic acid.

6. The durable flame retardant rubber material of claim 5, wherein the raw rubber comprises one or more of neoprene, natural rubber and chlorinated polyethylene rubber, and the content of chlorine in the chlorinated polyethylene rubber is 30-40% of the mass of the chlorinated polyethylene rubber.

7. The durable flame retardant rubber material as in claim 6, wherein the mass ratio of the chloroprene rubber, the natural rubber and the chlorinated polyethylene rubber in the raw rubber is (65-80): (10-25).

8. The durable flame-retardant rubber material as claimed in claim 5, wherein the catalyst is potassium iodide, and the mass ratio of the catalyst to the modifier is (1-5): (0.05-1).

9. A durable flame retardant rubber material as in claim 5 wherein said reinforcing filler comprises carbon black and/or white carbon, said flame retardant comprises aluminum hydroxide and/or tetrabromophthalic anhydride, and said active agent is one or more of magnesium oxide and stearic acid.

10. The durable flame retardant rubber material of claim 5, wherein the antioxidant comprises one or more of ODA, 6PPD, N-xylyl p-phenylenediamine, 2-mercaptomethylbenzimidazole zinc salt, and microcrystalline wax.

11. The durable flame retardant rubber material of claim 5, wherein the plasticizer comprises dioctyl sebacate and/or maleic anhydride modified liquid polybutadiene, and the content of maleic anhydride in the maleic anhydride modified liquid polybutadiene is 8% -18% of the mass of the maleic anhydride modified liquid.

12. The durable flame retardant rubber material of claim 11, wherein the mass ratio of dioctyl sebacate to maleic anhydride modified liquid polybutadiene in the plasticizer is (6-12): (5-20).

13. The durable flame-retardant rubber material according to claim 5, wherein the vulcanization accelerator comprises a vulcanizing agent and an accelerator, and the vulcanizing agent is two or more of zinc oxide, magnesium oxide and sulfur; the accelerant is two or more of N, N-m-phenylene bismaleimide, 2-dithio-dibenzothiazyl, N-cyclohexyl-2-benzothiazole sulfenamide, tetramethyl thiuram monosulfide and triazole dimercaptoamine salt.

14. A preparation method of a durable rubber material is characterized by comprising the following steps:

(1) uniformly mixing the raw rubber, adding a modifier and a catalyst, and mixing to obtain modified raw rubber;

(2) adding a reinforcing filler and a flame retardant, mixing, uniformly mixing, cooling, adding an active agent and a plasticizer, and continuously stirring and mixing;

(3) and after uniformly mixing, cooling again, adding a vulcanization accelerator and an anti-aging agent, and mixing to obtain the durable flame-retardant rubber material.

Technical Field

The invention belongs to the field of high polymer materials, and particularly relates to a modifier for a durable flame-retardant rubber material and a preparation method thereof, and a durable rubber material and a preparation method thereof.

Background

In recent years, the fire protection requirements of rail vehicles are more and more strict, and the EN45545 standard newly established and required to be implemented in the European Union clearly provides corresponding fire resistance requirements, so that the requirements of various major host plants on the durability of rubber materials of rail vehicles are more and more strict, the service life requirements are nearly doubled, and the service life of the rubber materials is greatly challenged from 6 years and 8 years to more than 10 years and 12 years. Although neoprene has good durability in common synthetic rubbers, neoprene products (e.g., air springs, air ducts, dust covers, etc.) that are exposed to dynamic environments for extended periods of time still have difficulty meeting long-life requirements, particularly for flame retardant products. In addition, the pure chloroprene rubber has poor low temperature resistance and poor rolling, forming and vulcanizing process performances, and the qualification rate of the air spring air bag and the air conduit of the pure chloroprene rubber is only 50-60 percent, so the cost is high.

In order to improve the durability, a mixed rubber system is adopted as a common method in the industry, but the compatibility between different rubber materials and fillers is poor, the compatibility principle of different rubber materials and filler systems is different, a proper modifier is matched according to the difference of rubber materials of a rubber system, so that a better compatibility effect can be exerted, and the problem of rubber material compatibility is solved by selecting a proper mixed rubber system.

Disclosure of Invention

The invention aims to solve the technical problems that the compatibility of a rubber system is poor, the defects and shortcomings in the background technology are overcome, and the modifier for the durable flame-retardant rubber material and the preparation method thereof, and the durable rubber material and the preparation method thereof are provided.

In order to solve the technical problems, the technical scheme provided by the invention is as follows:

a modifier for durable flame-retardant rubber materials is 3, 4-diamino- (1, 1' -biphenyl) -3, 5-dicarboxylic acid.

In order to further improve the chemical compatibility among sizing material, filling material and flame retardant, the invention provides a small molecule modifier containing double amino and double carboxyl for the first time, 3, 4-diamino- (1, 1' -biphenyl) -3, 5-dicarboxylic acid (marked as DBDA), and the molecular structural formula is shown in figure 1. The surface of the DBDA has active groups, the DBDA is easy to react with raw rubber, a flame retardant, a reinforcing filler and other raw materials, the modification effect on the raw rubber can be well completed, the chemical compatibility among the raw materials is improved, and the durable heat-resistant property of the chloroprene rubber material is further improved.

DBDA is a small molecule modifier, two amino groups are in ortho positions, and a certain steric hindrance exists between the amino groups, so that the modifier is used in a rubber system and cannot cause scorching.

Amino and carboxyl in DBDA are not adjacent, and self-condensation is not easy to occur. According to a benzene ring pi electron resonance structure, double ortho-position groups have low activity, and when the modified chloroprene rubber is used for rubber modification, after amino groups react with chloroprene rubber and natural rubber, the chloroprene rubber and the natural rubber are both high polymers, so that the molecular volume is extremely large, and COOH at ortho-positions directly loses activity due to the influence of steric effect. The amino group and the carboxyl group of DBDA are not adjacent, so that the inactivation caused by steric effect is avoided, and the DBDA is suitable for serving as a modifier of chloroprene rubber and natural rubber.

Under a general technical concept, the invention also provides a preparation method of the modifier for the durable flame-retardant rubber material, which comprises the steps of adding 4-bromo-1, 2-phenylenediamine, 3, 5-dicarboxyphenylboronic acid, a modification catalyst and weak base into a solvent, evaporating the solvent after the reaction is finished, and drying to obtain the modifier.

Preferably, the molar ratio of the 4-bromo-1, 2-phenylenediamine, the 3, 5-dicarboxyphenylboronic acid, the modification catalyst, the weak base and the alcohol solvent is (1.0): (1.1-1.5):(0.01-0.05): (1.5-3): (30-60).

Preferably, the modified catalyst is palladium acetate, the weak base is carbonate, the solvent is an alcohol solvent, the reaction is a reflux reaction, and the solvent is evaporated by rotary evaporation.

Under a general technical concept, the invention also provides a durable flame-retardant rubber material, which comprises the following raw materials in parts by weight:

100 parts of raw rubber;

1-5 parts of a modifier;

0.05-1 part of catalyst;

30-50 parts of reinforcing filler;

20-50 parts of a flame retardant;

6-12 parts of an anti-aging agent;

11-32 parts of a plasticizer;

3-5 parts of an active agent;

5-9 parts of a vulcanization accelerator;

wherein the modifier is 3, 4-diamino- (1, 1' -biphenyl) -3, 5-dicarboxylic acid.

According to the invention, the flame retardant is added into the raw rubber, so that the obtained rubber material has excellent durability and high flame retardant effect.

Preferably, the raw rubber comprises one or more of chloroprene rubber, natural rubber and chlorinated polyethylene rubber, and the chlorine content in the chlorinated polyethylene rubber is 30-40% of the mass of the chlorinated polyethylene rubber; more preferably, the natural rubber is a constant viscosity rubber, and more preferably, the constant viscosity rubber CV-60; the chlorine content of the chlorinated polyethylene rubber is 36% of the mass of the chlorinated polyethylene rubber.

The chloroprene rubber, the general solid natural rubber and the chlorinated polyethylene rubber are used in a combined system, and the low-temperature resistance of the chloroprene rubber and the defects of poor calendering, forming and vulcanizing processes can be improved by adding a proper amount of the general solid natural rubber; compared with chloroprene rubber, the chlorinated polyethylene rubber has a saturated molecular chain structure, and the proper amount of the chlorinated polyethylene rubber can obviously improve the heat resistance, ozone resistance, fatigue resistance and other properties of the rubber material and improve the durability of the rubber material.

The rubber system in the invention is Chloroprene Rubber (CR), Natural Rubber (NR), chlorinated polyethylene rubber (CM) and carbon black, white carbon black and aluminum hydroxide, and the solubility parameter delta of NR and CR is about 16 (J/CM)³)^1/2On the left and right, and the main chain structures of NR and CR are the same, therefore, CR can be regarded as a polar high polymer after partial methyl on the side chain of NR is substituted by chlorine, and comprehensive analysis shows that NR and CR can achieve limited compatibility. CM is a polar polymer with a high chlorine content and chlorine does not have hydrogen bonding, CM and CR are only limitedly compatible according to similar compatibility rules. NR and CR are of limited compatibility, CR and CM are of limited compatibility, CR provides a bridge between the non-polar NR and the polar CM, and thus a physically limited portion of the compatibility between NR, CR and CM is achieved, which is the basis for the preparation of the system.

The sulfurization active sites of NR are on the carbon chain and those of CR and CM are on the chlorine of the side chain. The patent adopts DBDA containing amino to modify CR and CM, so that the chlorine on the side chains of CR and CM is replaced by amino. Chlorine is an electron-withdrawing group, and amino is a strong electron-donating group, so that the entering of amino can improve the pi electron cloud density on the double bond of the CR and CM main chains, and the activity of the double bond on the CR and CM main chains is improved, which means that CR and CM can share a vulcanization promoting system with NR after being modified by DBDA, and on the basis of physical limited compatibility, the compatibility of a raw rubber system is further improved by activating the activity of the double bond of CR and CM and adopting the vulcanization promoting system, and the modification effect is fully exerted.

In the filler part, because carbon black, white carbon black and aluminum hydroxide are all nano-scale particle molecules, the blending between the filler and the rubber material is difficult to realize only through physical and mechanical actions. The raw rubber parts NR, CR and CM are compatible through physical and chemical actions, two amino groups in DBDA react with chlorine, the high-activity m-dicarboxyl on the other side can react with hydroxyl in the filler through condensation reaction, and the raw rubber and the filler are tightly combined through chemical covalent bonds. The reason for using small molecule substances containing diamino and dicarboxy is to increase the reaction probability and thus the crosslinking density.

The chlorinated polyethylene rubber has over-high chlorine content, over-high polarity, no elasticity and property similar to that of polyvinyl chloride; too low a chlorine content, easy to crystallize and cause loss of elasticity, properties close to those of polyethylene, and both of them cause deterioration of the properties of the chlorinated polyethylene rubber.

Preferably, the mass ratio of the chloroprene rubber, the natural rubber and the chlorinated polyethylene rubber in the raw rubber is (65-80): (10-25).

Preferably, the catalyst is potassium iodide, and the mass ratio of the catalyst to the modifier is (1-5): (0.05-1).

Preferably, the reinforcing filler comprises carbon black and/or white carbon black, the flame retardant comprises aluminum hydroxide and/or tetrabromophthalic anhydride, and the active agent is one or more of magnesium oxide and stearic acid.

Preferably, the antioxidant comprises one or more of ODA, 6PPD, N-xylyl p-phenylenediamine, 2-thiol methyl benzimidazole zinc salt and microcrystalline wax.

The ODA and the microcrystalline wax mainly play a role in the aging protection of the rubber material in the early stage and the middle stage; the 2-thiol methyl benzimidazole zinc salt is matched with 6PPD and N, N-xylyl p-phenylenediamine for use, so that a synergistic protection effect is achieved, and the durability of the rubber material is further improved.

Preferably, the plasticizer comprises dioctyl sebacate and/or maleic anhydride modified liquid polybutadiene, wherein the content of maleic anhydride in the maleic anhydride modified liquid polybutadiene is 8% -18% of the mass of the maleic anhydride modified liquid, and more preferably, the content of maleic anhydride is 15% of the mass of the maleic anhydride modified liquid;

on one hand, the maleic anhydride modified liquid polybutadiene selected by the invention can replace part of conventional plasticizers, improve the compatibility between polymers and fillers (such as carbon black), promote the uniform dispersion of the fillers and improve the physical and mechanical properties of rubber materials; on the other hand, the compatibility of the chloroprene rubber and the general solid natural rubber can be improved, so that the rubber compound is more uniform; secondly, the Tg of the neoprene modified by the dioctyl sebacate is very low, and the low-temperature resistance of the neoprene modified by the dioctyl sebacate can be obviously improved, so that the temperature range of the neoprene modified by the dioctyl sebacate is wider.

Preferably, the mass ratio of dioctyl sebacate to maleic anhydride modified liquid polybutadiene in the plasticizer is (6-12): (5-20).

Preferably, the vulcanization accelerator comprises a vulcanizing agent and an accelerator, wherein the vulcanizing agent is two or more of zinc oxide, magnesium oxide and sulfur; the accelerant is two or more of N, N-m-phenylene bismaleimide, 2-dithio-dibenzothiazyl, N-cyclohexyl-2-benzothiazole sulfenamide, tetramethyl thiuram monosulfide and triazole dimercaptoamine salt.

Under a general technical concept, the present invention also provides a method for preparing a durable flame retardant rubber material, comprising the steps of:

(1) uniformly mixing the raw rubber, adding a modifier and a catalyst, and mixing to obtain modified raw rubber;

(2) adding a reinforcing filler and a flame retardant, mixing, uniformly mixing, cooling, adding an active agent and a plasticizer, and continuously stirring and mixing;

(3) and after uniformly mixing, cooling again, adding a vulcanization accelerator and an anti-aging agent, and mixing to obtain the durable flame-retardant rubber material.

Preferably, the mixing temperature of the modifier and the catalyst added in the step (1) is 40-80 ℃, and the time is 5-10 min; in the step (2), the temperature is reduced to be below 100 ℃; in the step (3), the temperature is reduced to below 50 ℃.

Compared with the prior art, the invention has the beneficial effects that:

(1) the invention provides a modifier DBDA for a durable flame-retardant rubber material, wherein the surface of the DBDA has active groups, the DBDA is easy to react with raw rubber, a flame retardant, a reinforcing filler and other raw materials, the modification effect on the raw rubber can be well completed, the chemical compatibility among the raw materials is improved, and the durable heat-resistant property of the rubber material is further improved.

(2) The durable flame-retardant rubber material comprehensively improves the compatibility of a rubber system through DBDA, has excellent long-term thermal oxygen resistance, ozone resistance, fatigue aging resistance and other properties, and has excellent durability under static and dynamic conditions. The rubber material can be used for outer layer rubber of an air spring, a fireproof/dust hood, an air conduit and other protective layers to play an excellent long-acting protective role, and the risk of aging and cracking in the operation of the original rubber material, especially cracking in the dynamic operation is overcome.

(3) The durable flame-retardant rubber material has excellent durability and can meet the flame-retardant requirement of EN 45545R 9 HL 2.

(4) The durable flame-retardant rubber material has excellent low-temperature resistance and wider use temperature range; meanwhile, the durable material has good forming and vulcanizing process performances.

(5) The durable flame-retardant rubber material prepared by the invention has the advantages of simple method and mixing process, high equipment universality, lower cost and stable performance.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.

FIG. 1 is the structural formula of the 3, 4-diamino- (1, 1' -biphenyl) -3, 5-dicarboxylic acid modifier of example 1;

FIG. 2 is an IR spectrum of a 3, 4-diamino- (1, 1' -biphenyl) -3, 5-dicarboxylic acid modifier of example 1;

FIG. 3 is a chemical reaction formula for the preparation of 3, 4-diamino- (1, 1' -biphenyl) -3, 5-dicarboxylic acid modifier in example 1;

FIG. 4 is the mechanism of modification of raw rubber by the 3, 4-diamino- (1, 1' -biphenyl) -3, 5-dicarboxylic acid modifier of example 1;

FIG. 5 shows the reaction mechanism of the modified crude rubber, carbon black, white carbon black, aluminum hydroxide and tetrabromophthalic anhydride in example 1.

Detailed Description

In order to facilitate understanding of the invention, the invention will be described more fully and in detail with reference to the accompanying drawings and preferred embodiments, but the scope of the invention is not limited to the specific embodiments below.

Unless otherwise defined, all terms of art used hereinafter have the same meaning as commonly understood by one of ordinary skill in the art. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of the present invention.

Unless otherwise specifically stated, various raw materials, reagents, instruments, equipment and the like used in the present invention are commercially available or can be prepared by existing methods.

The rubber materials of example 1, example 2, example 3 and comparative example were prepared from the chemical raw materials in table 1, respectively.

Table 1 parts by mass of raw materials of example 1, example 2, example 3 and comparative example

Example 1:

the modifier used in this example was 3, 4-diamino- (1, 1' -biphenyl) -3, 5-dicarboxylic acid.

The modifier DBDA is prepared from 4-bromo-1, 2-phenylenediamine and 3, 5-dicarboxyphenylboronic acid, and palladium acetate (Pd (OAc)₂) As modified catalyst, carbonate as weak base and alcohol as solvent, and through Suzuki coupling reaction, 4-bromo-1, 2-phenylenediamine (0.1 mo) is added into the reaction tubel,18.7g), 3, 5-dicarboxyphenylboronic acid (0.12mol,21.2g), palladium acetate (0.002mol,0.45g), potassium carbonate (0.2mol,27.6g) and 500mL of an ethanol solvent were refluxed for 10 hours. And after the reaction is finished, spin-drying the solvent and drying to obtain the DBDA.

The raw materials of the durable flame-retardant rubber material of this example are shown in Table 1.

The preparation method of the durable flame-retardant rubber material in the embodiment comprises the following steps:

adopting the raw materials and the proportion shown in the table 1, uniformly mixing chloroprene rubber, general solid natural rubber and chlorinated polyethylene rubber in an open mill or an internal mixer at the temperature of 40-80 ℃, adding modifiers DBDA and KI, and mixing for 5-10 min; after the modification of the crude rubber is finished, adding carbon black, white carbon black, aluminum hydroxide and tetrabromophthalic anhydride, and mixing for 2-5 min; cooling to below 100 deg.C after feeding completely, sequentially adding activator (magnesium oxide, stearic acid) and plasticizer (dioctyl sebacate), and stirring for 2-5 min; cooling to below 50 deg.C after mixing, adding vulcanization accelerator (zinc oxide, sulfur, DM, CBS, NA-22) and antioxidant (ODA, 6PPD, N-xylyl p-phenylenediamine, microcrystalline wax), and making into durable flame retardant rubber material.

FIG. 3 shows the chemical reaction formula for preparing modifier DBDA of this example.

Fig. 1 is a molecular structural formula of a modifier DBDA in this example, and fig. 2 is an infrared spectrum of the modifier DBDA in this example.

Fig. 4 shows the modification mechanism of the modifier DBDA in this embodiment for neoprene, general solid natural rubber, and chlorinated polyethylene rubber, where the amino group in the DBDA can perform a substitution reaction with chlorine in the neoprene and the chlorinated polyethylene rubber under the catalysis of a potassium iodide catalyst.

FIG. 5 is a reaction mechanism of the modified crude rubber, carbon black, white carbon black, aluminum hydroxide and tetrabromophthalic anhydride of example 1; the surface of the carbon black contains hydroxyl and carboxyl, the surface of the white carbon black contains hydroxyl, the surface of the aluminum hydroxide contains hydroxyl, the tetrabromophthalic anhydride contains high-activity anhydride, and DBDA and raw rubber, carbon black, white carbon black, aluminum hydroxide and tetrabromophthalic anhydride can generate complex chemical reaction, so that the overall compatibility of a rubber system is improved, and the specific action mechanism is as follows:

(1) the amino in DBDA can generate substitution reaction with chlorine in chloroprene rubber and chlorinated polyethylene rubber under the catalysis of a catalyst;

(2) carrying out amidation reaction on amino in DBDA and anhydride in tetrabromophthalic anhydride;

(3) carboxyl in DBDA and hydroxyl on the surfaces of carbon black and white carbon black are subjected to esterification reaction;

(4) and carrying out esterification reaction on carboxyl white carbon black on the surface of the carbon black and hydroxyl on the surface of the aluminum hydroxide.

Example 2:

the modifier DBDA of this example and its preparation were the same as in example 1.

The raw materials of the durable flame-retardant rubber material of this example are shown in Table 1.

The preparation method of the durable flame-retardant rubber material in the embodiment comprises the following steps:

uniformly mixing chloroprene rubber, general solid natural rubber and chlorinated polyethylene rubber in an open mill or an internal mixer at the temperature of 40-80 ℃, adding modifiers DBDA and KI, and mixing for 5-10 min; after the modification of the crude rubber is finished, adding carbon black, white carbon black, aluminum hydroxide and tetrabromophthalic anhydride, and mixing for 2-5 min; cooling to below 100 deg.C after feeding completely, sequentially adding activator (magnesium oxide, stearic acid), plasticizer (dioctyl sebacate, and maleic anhydride modified liquid polybutadiene), and stirring for 2-5 min; cooling to below 50 deg.C after mixing, adding vulcanization accelerator (zinc oxide, sulfur, DM, TMTM, FSH) and antioxidant (ODA, 6PPD, N-xylyl-p-phenylenediamine, 2-thiol methyl benzimidazole zinc salt, microcrystalline wax), and making into durable flame-retardant rubber material.

Example 3:

the modifier DBDA of this example and its preparation were the same as in example 1.

The raw materials of the durable flame-retardant rubber material of this example are shown in Table 1.

The preparation method of the durable flame-retardant rubber material in the embodiment comprises the following steps:

uniformly mixing chloroprene rubber, general solid natural rubber and chlorinated polyethylene rubber in an open mill or an internal mixer at the temperature of 40-80 ℃, adding modifiers DBDA and KI, and mixing for 5-10 min; after the modification of the crude rubber is finished, adding carbon black, white carbon black, aluminum hydroxide and tetrabromophthalic anhydride, and mixing for 2-5 min; cooling to below 100 deg.C after feeding completely, sequentially adding activator (magnesium oxide, stearic acid), plasticizer (dioctyl sebacate, and maleic anhydride modified liquid polybutadiene), and stirring for 2-5 min; cooling to below 50 deg.C after mixing, adding vulcanization accelerator (zinc oxide, sulfur, HVA-2, DM, TMTM, FSH) and antioxidant (ODA, 6PPD, N-xylyl p-phenylenediamine, 2-thiol methyl benzimidazole zinc salt, microcrystalline wax), and taking down the sheet to obtain the durable flame-retardant rubber material.

Comparative example 1

The preparation method of comparative example 1 includes the following steps:

chloroprene rubber and general solid natural rubber are added into an internal mixer to be mixed uniformly, and the temperature is controlled to be 40-80 ℃; then adding an active agent (magnesium oxide and stearic acid) for mixing for 3 minutes; then adding reinforcing filler (carbon black N550 and white carbon black), flame retardant (aluminum hydroxide and tetrabromophthalic anhydride ester) and plasticizer (dioctyl sebacate), and continuously mixing for 5 minutes, wherein the mixing temperature is controlled at 50-110 ℃; cooling the mixed rubber to below 50 ℃, adding the vulcanization accelerator (zinc oxide, sulfur, DM, CBS, NA-22) and the anti-aging agent (ODA, 6PPD and microcrystalline wax) into an internal mixer for mixing, and discharging rubber when the temperature of the rubber material reaches above 100 ℃.

TABLE 2 results of measuring properties of rubber materials in examples and comparative examples

The durable flame-retardant rubber material prepared according to the formula shown in Table 1 was vulcanized at 150 ℃ for 30 minutes, and the properties of the vulcanized rubber are shown in Table 2. From the test results in table 2, it can be seen that compared with comparative example 1, the durable flame retardant rubber material of the present invention has more excellent long-term thermal oxygen resistance, ozone resistance, fatigue aging resistance, and simultaneously has better low temperature resistance and adhesion performance; has good processing fluidity, scorching safety and better processing performance.

The durable flame-retardant rubber material disclosed by the invention has the fire resistance meeting the HL2 grade requirement in EN45545-2, solves the technical problem that the durability, the flame retardance and the functionality of chloroprene rubber cannot be simultaneously considered, can be used for outer layer rubber of an air spring, a fireproof/dust cover, an air conduit and other protective layers to play an excellent long-acting protection role, and overcomes the risks of aging and cracking in the operation of the original rubber material, especially cracking in the dynamic operation.

In addition to the above embodiments, the present invention also includes other embodiments, and any technical solutions formed by equivalent transformation or equivalent replacement should fall within the scope of the claims of the present invention.