阅读说明：本技术 阻燃耐低温氯丁混炼胶及其制备方法 (Flame-retardant low-temperature-resistant chloroprene rubber compound and preparation method thereof ) 是由 汪必宽 于 2020-06-28 设计创作，主要内容包括：本发明公开一种阻燃耐低温氯丁混炼胶,由如下重量份原料制成：55-70份改性氯丁橡胶,10-15份复合纳米填料,5-10份乙烯-丙烯共聚物,1-3份防老剂D；本发明还公开了一种阻燃耐低温氯丁混炼胶的制备方法；将改性氯丁橡胶、氧化锌、复合纳米填料和防老剂D混合均匀,加入开炼机中混炼,制得混炼胶；将乙烯-丙烯共聚物在160-170℃的双辊开炼机中熔融塑化,之后加入混炼胶,硫化5-8min,硫化结束后在150-160℃下热压10min,制得阻燃耐低温氯丁混炼胶；氯丁橡胶为结晶型聚合物耐低温性能差,步骤S2中通过化合物A和氯丁橡胶共混,对氯丁橡胶进行改性,能够赋予制成的改性氯丁橡胶优异的耐低温性能。(The invention discloses a flame-retardant low-temperature-resistant chloroprene rubber compound which is prepared from the following raw materials in parts by weight: 55-70 parts of modified chloroprene rubber, 10-15 parts of composite nano filler, 5-10 parts of ethylene-propylene copolymer and 1-3 parts of anti-aging agent D; the invention also discloses a preparation method of the flame-retardant low-temperature-resistant chloroprene rubber compound; uniformly mixing the modified chloroprene rubber, the zinc oxide, the composite nano filler and the anti-aging agent D, and adding the mixture into an open mill for mixing to prepare rubber compound; melting and plasticizing the ethylene-propylene copolymer in a two-roll open mill at the temperature of 160-; chloroprene rubber is a crystalline polymer and has poor low-temperature resistance, and the chloroprene rubber is modified by blending the compound a and chloroprene rubber in step S2, so that the prepared modified chloroprene rubber has excellent low-temperature resistance.)

1. The flame-retardant low-temperature-resistant chloroprene rubber compound is characterized by being prepared from the following raw materials in parts by weight: 55-70 parts of modified chloroprene rubber, 10-15 parts of composite nano filler, 5-10 parts of ethylene-propylene copolymer and 1-3 parts of anti-aging agent D;

the modified chloroprene rubber is prepared by the following method:

step S1, adding isoprene into a beaker filled with 10% potassium hydroxide solution according to the weight ratio of 1: 2, soaking for 10-12h, keeping constant-speed stirring during the soaking process, transferring the isoprene into a three-neck flask after the soaking is finished, then adding zeolite and calcium hydride, heating and refluxing for 5h at 65-70 ℃ to prepare refined isoprene, adding the refined isoprene and a catalyst into a reaction kettle, adding the reaction kettle into an ice water bath to react for 4h, transferring into a constant-temperature water bath at 55-60 ℃ to continue to react for 5h, dropwise adding 1% hydrochloric acid ethanol solution, filtering, washing with absolute ethanol for three times to prepare a compound A, and controlling the weight ratio of the refined isoprene to the catalyst to be 5-8: 1;

and step S2, drying the compound A at 75-80 ℃ for 1h, adding the compound A into an open mill for plasticating, wrapping a roller, controlling the plasticating temperature to be 65-70 ℃, adding chloroprene rubber, performing thin passing for 5 times, uniformly mixing, wrapping the roller, sequentially adding magnesium oxide, stearic acid, phthalic acid ester, an anti-aging agent and zinc oxide, performing left-right cutting for four times, and performing thin passing for 6 times to obtain the modified chloroprene rubber.

2. The flame-retardant low-temperature-resistant chloroprene rubber compound according to claim 1, wherein the catalyst in step S1 is one or both of titanate catalysts PVAC-1 and RTV-1.

3. The flame-retardant low-temperature-resistant chloroprene rubber compound according to claim 1, wherein the weight ratio of the compound a, chloroprene rubber, magnesium oxide, stearic acid, phthalate, antioxidant and zinc oxide in step S2 is controlled to 0.8-1: 2: 0.1: 0.2-0.3: 0.05-0.08: 0.02: 0.1.

4. The flame-retardant low-temperature-resistant chloroprene rubber compound according to claim 1, wherein the antioxidant in step S2 is one or both of N-phenyl- α -aniline and p-phenylenediamine.

5. The flame-retardant low temperature-resistant chloroprene rubber compound according to claim 1, wherein the composite nano-filler is prepared by the following method:

(1) uniformly mixing montmorillonite, urea and ethanol according to the weight ratio of 3: 4-5: 1, transferring the mixture into a three-neck flask, heating the mixture in a water bath at 45-55 ℃, stirring the mixture for 2-3 hours at the rotating speed of 140r/min to prepare mixed slurry, performing suction filtration, washing the mixed slurry with deionized water for three times, washing the mixed slurry with absolute ethyl alcohol for three times, drying and grinding the washed mixed slurry to prepare modified montmorillonite;

(2) mixing the modified montmorillonite and the nano-silica, stirring at the rotation speed of 1000-1200r/min for 40-50min to prepare a composite particle precursor, then adding hexamethyldisilazane, magnetically stirring for 15-30min, then adding IFR, heating to 100-110 ℃, reacting for 4-5h at the temperature, filtering, and washing with deionized water for three times to prepare the high-flame-retardant composite filler.

6. The flame-retardant low-temperature-resistant chloroprene rubber compound according to claim 5, wherein the weight ratio of the modified montmorillonite, the nano-silica, the hexamethyldisilazane and the IFR is controlled to be 1: 2: 50-60: 0.2-0.5.

7. The method for preparing a flame-retardant low-temperature-resistant chloroprene rubber compound according to claim 1, comprising the following steps: uniformly mixing the modified chloroprene rubber, the zinc oxide, the composite nano filler and the anti-aging agent D, and adding the mixture into an open mill for mixing to prepare rubber compound; melting and plasticizing the ethylene-propylene copolymer in a two-roll open mill at 160-170 ℃, adding the rubber compound, vulcanizing for 5-8min, and hot-pressing at 150-160 ℃ for 10min after the vulcanization is finished to obtain the flame-retardant low-temperature-resistant chloroprene rubber compound.

Technical Field

The invention belongs to the technical field of rubber preparation, and particularly relates to a flame-retardant low-temperature-resistant chloroprene rubber compound and a preparation method thereof.

Background

Chloroprene rubber is one of important varieties of synthetic rubber, has excellent mechanical properties, heat resistance and corrosion resistance, and is widely used for manufacturing industrial rubber products, such as wire and cable sheaths, oil-resistant rubber tube rubber plates, conveying belts, various adhesive tapes, shoe binders and the like. However, chloroprene rubber has poor cold resistance, presents a glass state below minus 40 ℃, and can age under the influence of oxygen, water, ozone and the like in the long-term use process, and the defects limit the application of the chloroprene rubber in some special fields.

The Chinese invention patent CN105968466A discloses a low-temperature-resistant and aging-resistant chloroprene rubber composite material, which comprises the following raw materials: chloroprene rubber, natural rubber, butadiene rubber, styrene-isoprene block copolymer rubber, polybutylene terephthalate, maleic anhydride graft modified natural rubber, nano zinc oxide, nano magnesium oxide, stearic acid, 2, 5-dimethyl-2, 5-di-tert-butyl hexane peroxide, cyanuric acid, triallyl trimellitate, nano silicon dioxide, precipitated white carbon black, purple carbon black, nano microcrystalline cellulose, silane coupling agent KH-550 modified montmorillonite, an anti-aging agent, an accelerator NA-22, an accelerator TE, an accelerator ZIP, vinyl tri (beta-methoxyethoxy) silane, dioctyl azelate, dioctyl sebacate and titanate coupling agent NDZ-201. The low-temperature-resistant and aging-resistant chloroprene rubber composite material provided by the invention has the advantages of high strength, good low-temperature resistance and excellent aging resistance.

Disclosure of Invention

In order to overcome the technical problems, the invention provides a flame-retardant low-temperature-resistant chloroprene rubber compound and a preparation method thereof. The composite filler can release water vapor and metal oxide when being burnt, the water vapor can reduce the concentration of a subsequent burnt object, and the metal oxide has excellent heat resistance and is coated on the surface of the burnt object to further enhance the flame retardant property, so that the prepared composite filler has excellent flame retardant property and can endow the composite filler with excellent flame retardant property when being mixed with the modified chloroprene rubber.

The technical problems to be solved by the invention are as follows:

chloroprene rubber is a crystalline polymer, has a high molecular chain regularity, is easily crystallized and hardened to lose its elasticity, and has poor low-temperature resistance because the rubber undergoes a morphological transition from a rubbery state to a glassy state when the temperature is lowered.

The purpose of the invention can be realized by the following technical scheme:

the flame-retardant low-temperature-resistant chloroprene rubber compound is prepared from the following raw materials in parts by weight: 55-70 parts of modified chloroprene rubber, 10-15 parts of composite nano filler, 5-10 parts of ethylene-propylene copolymer and 1-3 parts of anti-aging agent D;

the modified chloroprene rubber is prepared by the following method:

step S1, adding isoprene into a beaker filled with 10% potassium hydroxide solution according to the weight ratio of 1: 2, soaking for 10-12h, keeping constant-speed stirring during the soaking process, transferring the isoprene into a three-neck flask after the soaking is finished, then adding zeolite and calcium hydride, heating and refluxing for 5h at 65-70 ℃ to prepare refined isoprene, adding the refined isoprene and a catalyst into a reaction kettle, adding the reaction kettle into an ice water bath to react for 4h, transferring into a constant-temperature water bath at 55-60 ℃ to continue to react for 5h, dropwise adding 1% hydrochloric acid ethanol solution, filtering, washing with absolute ethanol for three times to prepare a compound A, and controlling the weight ratio of the refined isoprene to the catalyst to be 5-8: 1;

and step S2, drying the compound A at 75-80 ℃ for 1h, adding the compound A into an open mill for plasticating, wrapping a roller, controlling the plasticating temperature to be 65-70 ℃, adding chloroprene rubber, performing thin passing for 5 times, uniformly mixing, wrapping the roller, sequentially adding magnesium oxide, stearic acid, phthalic acid ester, an anti-aging agent and zinc oxide, performing left-right cutting for four times, and performing thin passing for 6 times to obtain the modified chloroprene rubber.

Step S1, adding isoprene into a beaker of 10% potassium hydroxide solution, soaking for 10-12h to remove residual polymerization inhibitor in the isoprene production process, adsorbing with zeolite and calcium hydride to obtain refined isoprene, adding catalyst, polymerizing isoprene under catalysis to generate compound A with a large amount of double bonds, and has a trans-structure and excellent elasticity and cold resistance, when compounded with chloroprene rubber in step S2, the chloroprene rubber is a crystalline polymer, has high molecular chain regularity, is easy to crystallize and harden to cause the loss of elasticity, and when the temperature is reduced, the rubber undergoes a form transition from a rubbery state to a glassy state, therefore, the low temperature resistance is poor, and the compound a and the chloroprene rubber are blended in step S2 to modify the chloroprene rubber, so that the resulting modified chloroprene rubber can be provided with excellent low temperature resistance.

Further, the catalyst in step S1 is one or two of titanate catalysts PVAC-1 and RTV-1.

Further, in step S2, the weight ratio of the compound A, the chloroprene rubber, the magnesium oxide, the stearic acid, the phthalic acid ester, the anti-aging agent and the zinc oxide is controlled to be 0.8-1: 2: 0.1: 0.2-0.3: 0.05-0.08: 0.02: 0.1.

Further, in step S2, the anti-aging agent is one or two of N-phenyl-alpha-aniline and p-phenylenediamine.

Further, the composite nanofiller is made by the following process:

(1) uniformly mixing montmorillonite, urea and ethanol according to the weight ratio of 3: 4-5: 1, transferring the mixture into a three-neck flask, heating the mixture in a water bath at 45-55 ℃, stirring the mixture for 2-3 hours at the rotating speed of 140r/min to prepare mixed slurry, performing suction filtration, washing the mixed slurry with deionized water for three times, washing the mixed slurry with absolute ethyl alcohol for three times, drying and grinding the washed mixed slurry to prepare modified montmorillonite;

(2) mixing the modified montmorillonite and the nano-silica, stirring at the rotation speed of 1000-1200r/min for 40-50min to prepare a composite particle precursor, then adding hexamethyldisilazane, magnetically stirring for 15-30min, then adding IFR, heating to 100-110 ℃, reacting for 4-5h at the temperature, filtering, and washing with deionized water for three times to prepare the high-flame-retardant composite filler.

Mixing montmorillonite, urea and ethanol according to the weight ratio of 3: 5: 1 in the step (1) to perform intercalation modification on the montmorillonite, wherein urea is used as an intercalating agent, so that on one hand, the interlayer spacing of the montmorillonite can be increased, and a space is provided for other molecules to enter the montmorillonite, and on the other hand, ammonia gas can be decomposed when the prepared modified montmorillonite is combusted, so that the combustion process is hindered; in the step (2), the modified montmorillonite and the nano-silica are mixed, modification is carried out through hexamethyldisilazane, hydroxyl on the surface of the silica can be subjected to dehydration condensation reaction with the hexamethyldisilazane, the silica is uniformly adsorbed on the surface of the modified montmorillonite to form a modified montmorillonite core, the nano-silica is a shell micron/nano core-shell structure, IFR is added, P element in the IFR and N element in the modified montmorillonite can be subjected to synergistic flame retardance, water vapor and metal oxide can be released when the composite filler is combusted, the concentration of a subsequent combustion product can be reduced through the water vapor, the metal oxide has excellent heat resistance and is coated on the surface of the combustion product to further enhance the flame retardance, and therefore the prepared composite filler has excellent flame retardance.

Further, the weight ratio of the modified montmorillonite to the nano-silica to the hexamethyldisilazane to the IFR is controlled to be 1: 2: 50-60: 0.2-0.5.

The preparation method of the flame-retardant low-temperature-resistant chloroprene rubber compound comprises the following steps: uniformly mixing the modified chloroprene rubber, the zinc oxide, the composite nano filler and the anti-aging agent D, and adding the mixture into an open mill for mixing to prepare rubber compound; melting and plasticizing the ethylene-propylene copolymer in a two-roll open mill at 160-170 ℃, adding the rubber compound, vulcanizing for 5-8min, and hot-pressing at 150-160 ℃ for 10min after the vulcanization is finished to obtain the flame-retardant low-temperature-resistant chloroprene rubber compound.

The invention has the beneficial effects that:

(1) the flame-retardant low-temperature-resistant chloroprene rubber compound takes modified chloroprene rubber, composite nano filler and the like as raw materials, isoprene is firstly added into a beaker of 10 percent potassium hydroxide solution to be soaked for 10 to 12 hours in the step S1 in the preparation process of the modified chloroprene rubber, the residual polymerization inhibitor in the isoprene production process is removed, then refined isoprene is prepared by adsorption of zeolite and calcium hydride, a catalyst is added, the isoprene is polymerized by itself under the catalysis action of the catalyst to generate a compound A, the compound A has a large number of double bonds and a trans-structure and has excellent elasticity and cold resistance, when the compound A is mixed with the chloroprene rubber in the step S2, the chloroprene rubber is a crystalline polymer, has high molecular chain regularity and is easy to crystallize and harden to cause the loss of elasticity, and when the temperature is reduced, the rubber is subjected to form transition and is changed from a rubber state to a glass state, therefore, the low temperature resistance is poor, and the compound a and the chloroprene rubber are blended in step S2 to modify the chloroprene rubber, so that the resulting modified chloroprene rubber can be provided with excellent low temperature resistance.

(2) In the preparation process of the composite nano filler, montmorillonite, urea and ethanol are mixed according to the weight ratio of 3: 5: 1 in the step (1), the montmorillonite is subjected to intercalation modification, and urea is used as an intercalating agent, so that on one hand, the interlayer spacing of the montmorillonite can be increased, a space is provided for other molecules to enter the montmorillonite, and on the other hand, ammonia gas can be decomposed when the prepared modified montmorillonite is combusted, so that the combustion process is hindered; in the step (2), the modified montmorillonite and the nano-silica are mixed and modified by hexamethyldisilazane, hydroxyl on the surface of the silica can be subjected to dehydration condensation reaction with the hexamethyldisilazane, the silica is uniformly adsorbed on the surface of the modified montmorillonite to form a micron/nano core-shell structure with the modified montmorillonite as a core and the nano-silica as a shell, and the P element in the IFR and the N element in the modified montmorillonite can be added to carry out synergistic flame retardance, when the composite filler is burnt, water vapor and metal oxide can be released, the water vapor can reduce the concentration of the subsequent combustion substances, the metal oxide has excellent heat resistance and is coated on the surface of the combustion substances to further enhance the flame retardant property, therefore, the prepared composite filler has excellent flame retardant property, and when the composite filler is mixed with the modified chloroprene rubber, the composite filler can be endowed with the excellent flame retardant property.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.