Anti-ozone agent for rubber, preparation method and application of anti-ozone agent and rubber

Abstract

The invention discloses an antiozonant for rubber. The molecular structure of the antiozonant simultaneously contains an arylamine functional group and a carbon-carbon double bond. The invention further discloses a preparation method and application of the antiozonant and rubber. Molecules of the anti-ozone agent for the rubber contain arylamine functional groups and carbon-carbon double bonds, the arylamine functional groups and the carbon-carbon double bonds have a synergistic effect, are migrated to the surface of a rubber product and can react with ozone, rubber molecular chains are prevented from being aged and broken by the ozone to generate cracks, the anti-ozone effect is fully achieved, the continuous action time is long, and the anti-ozone agent has a good anti-ozone effect. And the service life of the rubber is prolonged.

Description

Technical Field

[0001] The invention belongs to the field of rubber materials, and in particular relates to a rubber additive and a preparation method and application thereof, as well as a rubber. Background Art

[0002] As environmental pollution becomes increasingly serious, the concentration of ozone in the atmosphere is gradually increasing. Rubber products, especially rubber products containing unsaturated carbon-carbon double bonds in the molecular chain, are significantly affected by ozone during storage and use, causing discoloration and ozone cracking on the surface of the products, seriously affecting the appearance and function of rubber products.

[0003] As the most commonly used chemical antiozonant in the rubber industry, p-phenylenediamine organic compounds gradually diffuse to the rubber surface and react with ozone after being added to rubber composite materials. Before the ozone is consumed, the rubber will not be attacked by ozone, thus playing a role in protecting against ozone. Commonly used p-phenylenediamine antiozonants include dialkyl-substituted p-phenylenediamine, alkylaryl-substituted p-phenylenediamine and diaryl-substituted p-phenylenediamine. Among them, dialkyl-substituted p-phenylenediamine has good antiozonant effect, but high volatility and unsatisfactory sustained effect; diaryl-substituted p-phenylenediamine has better sustained effect, but the antiozonant effect is not as good as dialkyl p-phenylenediamine; the effect of alkylaryl-substituted p-phenylenediamine is between the two. It is difficult for the antiozonants in the prior art to achieve both good antiozonant effect and long duration of antiozonant effect. Therefore, it is of great significance to design and synthesize an antiozonant with good antiozonant effect and long duration of action. Summary of the invention

[0004] The technical problem to be solved by the present invention is to overcome the deficiencies and defects mentioned in the above background technology and provide an antiozonant for rubber with good anti-ozone effect and long lasting action time, as well as a preparation method and application thereof and a rubber.

[0005] In order to solve the above technical problems, the technical solution proposed by the present invention is: An antiozonant for rubber, wherein the molecular structure of the antiozonant contains both an aromatic amine functional group and a carbon-carbon double bond.

[0006] In the above antiozonants, preferably, the aromatic amine functional group includes one or more of dialkylphenylamine, alkylphenylamine and phenylamine.

[0007] In the above antiozonants, preferably, the carbon-carbon double bond is connected to two aromatic amine functional groups to form a conjugated structure.

[0008] Among the above antiozonants, preferably, the molecular structure of the antiozonant is as follows: ; Among them, R 1 , R2 , R 3 , R 4 is hydrogen, or is the same or different straight or branched chain alkyl group of 1 to 8 carbon atoms. More preferably, R 1 , R 2 , R 3 , R 4 The alkyl groups are straight or branched chain alkyl groups of 1 to 3 carbon atoms, which may be the same or different.

[0009] The antiozonant of the present invention is used for anti-ozone of rubber, and its molecular weight needs to be reasonably controlled to ensure a suitable migration rate. The antiozonant migrates from the inside of the rubber to the surface, and if the migration is too slow, it will not play an anti-ozone role; if the migration is too fast and the volatility is high, the anti-ozone sustained effect is poor. The antiozonant of this structural form is conducive to ensuring a suitable molecular weight by controlling the molecular weight of the terminal branch chain, has an appropriate migration rate and volatility, and can timely maintain the steady-state concentration on the surface of the rubber product, so that the anti-ozone sustained effect is better.

[0010] As a general technical concept, the present invention also provides a method for preparing the above-mentioned antiozonant, comprising the following steps: reacting a quaternary phosphine salt with a base to generate methylene triphenylphosphine, and subjecting the methylene triphenylphosphine to a Wittig reaction with a first raw material to obtain the antiozonant; Among them, the structural molecular formula of the first raw material is as follows: .

[0011] In the above preparation method, preferably, reacting a quaternary phosphine salt with a base to generate methylene triphenylphosphine comprises the following steps: under the protection of an inert gas, configuring a quaternary phosphine salt and an organic solvent into a mixed solution, adding an alkaline solution with a mass concentration of 2-50wt% (preferably 2-30wt%) under stirring at 0-20°C (preferably 0-10°C), and continuing to stir and react for 0.1-3h (preferably 0.3-2h) to obtain a methylene triphenylphosphine mixed solution; the quaternary phosphine salt comprises one or more of methyl triphenylphosphine chloride, methyl triphenylphosphine bromide and methyl triphenylphosphine iodide, the organic solvent comprises one or more of tetrahydrofuran, dimethylformamide, dimethyl sulfoxide and diethyl ether; the base comprises one or more of potassium tert-butoxide, sodium tert-butoxide, lithium tert-butoxide, sodium hydroxide and sodium carbonate; the molar ratio of the base to the quaternary phosphine salt is (1-2):1 (preferably (1-1.2):1).

[0012] In the above preparation method, preferably, methylene triphenylphosphine and the first raw material are subjected to Wittig reaction, comprising the following steps: under the protection of inert gas, the first raw material is dissolved in an organic solvent, mixed with methylene triphenylphosphine under stirring at 0-20°C (preferably 0-10°C), and the reaction is continued with stirring from room temperature to reflux temperature (preferably at reflux temperature) for 4-48h (preferably 5-12h). After the reaction is completed, the reaction mixture is poured into excess deionized water to separate the organic layer, the organic layer is washed with saturated sodium bicarbonate aqueous solution until neutral, anhydrous magnesium sulfate is added, stirred and dried for a day and night, filtered, and the filtrate is rotary evaporated to obtain a crude product, the crude product is separated by column chromatography, rotary evaporated, and vacuum dried at 10-40°C (preferably 20-35°C) to constant weight to obtain an antiozonant; the organic solvent comprises one or more of tetrahydrofuran, dimethylformamide, dimethyl sulfoxide and diethyl ether; the molar ratio of the quaternary phosphine salt to the first raw material is (1-2):1 (preferably (1-1.6):1).

[0013] As a general technical concept, the present invention also provides a use of the above antiozonant in ozone protection of rubber materials.

[0014] As a general technical concept, the present invention also provides a rubber, including a rubber matrix and an additive, wherein the molecular chain of the rubber matrix contains carbon-carbon double bonds, the additive includes an antiozonant, and the antiozonant is the above antiozonant. The rubber matrix includes natural rubber, styrene-butadiene rubber, butadiene rubber, isoprene rubber, chloroprene rubber, nitrile rubber, and rubbers used in combination in different proportions.

[0015] The aromatic amine functional group in the antiozonant molecule for rubber of the present invention includes a dialkylphenylamine, an alkylphenylamine or a phenylamine, which is easy to react with the electron-withdrawing reagent ozone, consumes ozone and prevents ozone from attacking the unsaturated carbon-carbon double bonds in the rubber molecular chain. In addition, the reaction product forms a charring protective film on the surface of the product to prevent ozone from continuing to penetrate into the rubber inner layer and destroy the rubber molecular chain; the carbon-carbon double bond in the antiozonant molecule can replace the carbon-carbon double bond in the rubber molecular chain and react with ozone, further enhancing the anti-ozone effect. The carbon-carbon double bond in the antiozonant molecule is connected with two aromatic amine functional groups to form a conjugated structure. On the one hand, the structural form is conducive to the synergistic effect of the aromatic amine functional group and the carbon-carbon double bond, and the anti-ozone effect is enhanced through the synergistic effect. On the other hand, the two aromatic amine functional groups contained in the structure can react with the aldehyde group and ketone group generated after the rubber macromolecule is broken due to ozone aging, and play a similar "cross-linking" role, preventing the rubber molecular chain from further degradation and inhibiting the generation of ozone cracking. In addition, the antiozonant of the present invention has a moderate molecular weight, an appropriate migration rate and volatility, and can timely maintain a steady concentration on the surface of the rubber product, so that the antiozonant has a better continuous effect.

[0016] In the present invention, the aromatic amine functional group and the carbon-carbon double bond have a synergistic effect, and the combination of the two needs to be limited. If the above two functional groups are not contained at the same time, such as the aromatic amine functional group is not contained, the anti-ozone effect is reduced; if the carbon-carbon double bond is not contained, the anti-ozone effect cannot be further improved. If the carbon-carbon double bond is not connected to the two aromatic amine functional groups and forms a conjugated structure, on the one hand, the aromatic amine functional group and the carbon-carbon double bond cannot play a synergistic role, and the anti-ozone effect is not ideal. On the other hand, the aromatic amine functional group cannot play a similar "cross-linking" role and cannot inhibit the occurrence of rubber ozone cracking. In the rubber containing carbon-carbon double bonds in the molecular chain, the above three situations cannot achieve better anti-ozone and its sustained effect.

[0017] Compared with the prior art, the advantages of the present invention are: The antiozonant for rubber of the present invention contains an aromatic amine functional group and a carbon-carbon double bond in the molecule, and the two can synergistically act with each other and migrate to the surface of the rubber product, and can react with ozone to prevent the rubber molecular chain from being broken and cracked due to ozone aging, thereby fully realizing the anti-ozone effect, and the continuous action time is long, which is beneficial to prolonging the service life of the rubber.

[0018] The preparation method of the present invention has high universality, is simple and easy to operate, can share organic synthesis instruments and equipment, is easy to realize industrial production, and has good market application value in the rubber industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0020] Figure 1 is the antiozonant A1 (1,1-bis(4-dimethylaminophenyl)ethylene) in Example 1 1 H NMR spectra.

[0021] Figure 2 This is the MS chart of the antiozonant A1 (1,1-bis(4-dimethylaminophenyl)ethylene) in Example 1. DETAILED DESCRIPTION

[0022] In order to facilitate the understanding of the present invention, the present invention will be described more comprehensively and meticulously below in conjunction with the accompanying drawings and preferred embodiments of the present invention, but the protection scope of the present invention is not limited to the following specific embodiments.

[0023] Unless otherwise defined, all the professional terms used below have the same meanings as those generally understood by those skilled in the art. The professional terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention.

[0024] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or prepared by existing methods.

[0025] Embodiment 1: An antiozonant for rubber, the molecular structure is as follows: .

[0026] The preparation method of the above-mentioned antiozonant for rubber comprises the following steps: (1) Under nitrogen protection, weigh 19 g of potassium tert-butoxide and 140 g of tetrahydrofuran to prepare a potassium tert-butoxide solution. Weigh 58 g of methyltriphenylphosphonium bromide and 90 g of tetrahydrofuran into a three-necked round-bottom flask. Add the potassium tert-butoxide solution at 0°C with stirring. Continue stirring for 2 h to obtain a methylenetriphenylphosphine mixed solution.

[0027] (2) Under nitrogen protection, 27 g of 4,4'-bis(dimethylamino)benzophenone and 100 g of tetrahydrofuran were weighed to prepare a solution, which was added to the above methylenetriphenylphosphine mixed solution at 0°C with stirring, and then the temperature was raised to reflux. The reaction mixture was stirred and reacted for 7 h. The reaction mixture was poured into excess deionized water, and the organic layer was separated. The organic layer was washed with a saturated sodium bicarbonate aqueous solution until neutral, and then anhydrous magnesium sulfate was added and stirred to dry for a day and night. The filtrate was filtered and rotary evaporated to obtain a crude product. The crude product was separated by column chromatography, rotary evaporated, and vacuum dried at 35°C to constant weight to obtain the antiozonant of this example, the product name is referred to as A1, and the yield is about 92%.

[0028] Figure 1 is the antiozonant A1 in Example 1 1 H NMR spectrum, Figure 2 is the MS diagram of the antiozonant A1 in Example 1, Figure 1 and Figure 2 It can be seen that the target product antiozonant A1 (1,1-bis(4-dimethylaminophenyl)ethylene) was synthesized in this embodiment.

[0029] Embodiment 2: An antiozonant for rubber, the molecular structure is as follows: .

[0030] The preparation method of the above-mentioned antiozonant for rubber comprises the following steps: (1) Under nitrogen protection, weigh 15 g of sodium tert-butoxide and 55 g of tetrahydrofuran to prepare a sodium tert-butoxide solution. Weigh 43 g of methyltriphenylphosphine chloride and 90 g of tetrahydrofuran into a three-necked round-bottom flask. Add the sodium tert-butoxide solution at 4°C and continue stirring for 1 h to obtain a methylenetriphenylphosphine mixed solution.

[0031] (2) Under nitrogen protection, 32 g of 4,4'-bis(diethylamino)benzophenone and 100 g of tetrahydrofuran were weighed to prepare a solution, which was added to the above methylenetriphenylphosphine mixed solution under stirring at 4°C, and then the temperature was raised to reflux. The reaction mixture was stirred for 6 h, and the reaction mixture was poured into excess deionized water to separate the organic layer. The organic layer was washed with a saturated sodium bicarbonate aqueous solution until neutral, and then anhydrous magnesium sulfate was added to stir and dry for a day and night, filtered, and the filtrate was rotary evaporated to obtain a crude product. The crude product was separated by column chromatography, rotary evaporated, and vacuum dried at 23°C to constant weight to obtain the antiozonant of this example, the product name is abbreviated as A2, and the yield is about 90%.

[0032] Application Example 1: The rubber compound was prepared according to the formula shown in Table 1. 1#, 2#, 3# and 4# were all prepared according to the conventional mixing process. No antiozonant was added to 1#, and antiozonant 6PPD containing only aromatic amine functional groups and antiozonant AFS containing only carbon-carbon double bonds were added to 2# and 3#, respectively, in contrast to 4# in which antiozonant A1 was directly added. Comparing the properties of the rubber compounds obtained from the four formulas, it can be proved that the antiozonant A1 has an antiozonant effect. If it does not contain aromatic amine functional groups or carbon-carbon double bonds, the antiozonant effect is poor.

[0033] Table 1: Basic formula of natural rubber composite materials (parts by weight)

[0034] The rubber compound prepared according to the formula shown in Table 1 was vulcanized at 150°C for 15 minutes, and the properties of the obtained vulcanized rubber are shown in Table 2. As can be seen from Table 2, without adding antiozonant A1 or adding antiozonant AFS, ozone cracking appeared in the vulcanized rubber after 24 hours; adding antiozonant 6PPD, ozone cracking appeared in the vulcanized rubber after 48 hours; adding antiozonant A1, the vulcanized rubber still did not show ozone cracking after 168 hours. It can be seen that antiozonant A1 has a good anti-ozone effect on natural rubber composites, can effectively improve the ozone resistance of vulcanized rubber, and has a good anti-ozone continuous effect.

[0035] Table 2: Properties of natural rubber vulcanizates

[0036] Application Example 2: The rubber compound was prepared according to the formula shown in Table 3, and both 5# and 6# were mixed according to the conventional mixing process.

[0037] Table 3: Basic formula of styrene-butadiene rubber composite materials (parts by mass)

[0038] The rubber compound prepared according to the formula shown in Table 3 was vulcanized at 150°C for 15 minutes, and the properties of the obtained vulcanized rubber are shown in Table 4. As can be seen from Table 4, the antiozonant A2 has a good anti-ozone effect on the styrene-butadiene rubber composite material, can effectively improve the ozone resistance of the vulcanized rubber, and has a good continuous anti-ozone effect.

[0039] Table 4: Properties of Styrene Butadiene Rubber Vulcanizate

[0040] Application Example 3: The rubber compound was prepared according to the formula shown in Table 5, and both 7# and 8# were mixed according to the conventional mixing process.

[0041] Table 5: Basic formula of butadiene rubber composite materials (parts by mass)

[0042] The rubber compound prepared according to the formula shown in Table 5 was vulcanized at 150°C for 20 minutes, and the properties of the obtained vulcanized rubber are shown in Table 6. As can be seen from Table 6, the antiozonant A1 has a good anti-ozone effect on the butadiene rubber composite material, can effectively improve the ozone resistance of the vulcanized rubber, and has a good continuous anti-ozone effect.

[0043] Table 6: Properties of butadiene rubber vulcanizate

[0044] Application example 4: The rubber compound was prepared according to the formula shown in Table 7, and both 9# and 10# were mixed according to the conventional mixing process.

[0045] Table 7: Basic formula of isoprene rubber composite materials (parts by mass)

[0046] The rubber compound prepared according to the formula shown in Table 7 was vulcanized at 150°C for 15 minutes, and the properties of the obtained vulcanized rubber are shown in Table 8. As can be seen from Table 8, the antiozonant A2 has a good anti-ozone effect on the isoprene rubber composite material, can effectively improve the ozone resistance of the vulcanized rubber, and has a good continuous anti-ozone effect.

[0047] Table 8: Properties of isoprene rubber vulcanizates

[0048] Application Example 5: The rubber compound was prepared according to the formula shown in Table 9, and 11# and 12# were mixed according to the conventional mixing process.

[0049] Table 9: Basic formula of chloroprene rubber composite materials (parts by mass)

[0050] The rubber compound prepared according to the formula shown in Table 9 was vulcanized at 150°C for 30 minutes, and the properties of the obtained vulcanized rubber are shown in Table 10. As can be seen from Table 10, the antiozonant A1 has a good anti-ozone effect on the chloroprene rubber composite material, can effectively improve the ozone resistance of the vulcanized rubber, and has a good continuous anti-ozone effect.

[0051] Table 10: Properties of chloroprene rubber vulcanizate

[0052] Application Example 6: The rubber compound was prepared according to the formula shown in Table 11. 13#, 14#, 15# and 16# were mixed according to the conventional mixing process.

[0053] Table 11: Basic formula of nitrile rubber composite materials (parts by weight)

[0054] The rubber compound prepared according to the formula shown in Table 11 was vulcanized at 150°C for 40 minutes, and the properties of the obtained vulcanized rubber are shown in Table 12. As can be seen from Table 12, the antiozonant A2 has a good anti-ozone effect on the nitrile rubber composite material, can effectively improve the ozone resistance of the vulcanized rubber, and has a good continuous anti-ozone effect.

[0055] Table 12: Properties of Nitrile Rubber Vulcanizate

[0056] Application Example 7: The rubber compound was prepared according to the formula shown in Table 13, and both 17# and 18# were mixed according to the conventional mixing process.

[0057] Table 13: Basic formula of natural rubber, butadiene rubber and chloroprene rubber composite materials (mass parts)

[0058] The rubber compound prepared according to the formula shown in Table 13 was vulcanized at 150°C for 20 minutes, and the properties of the obtained vulcanized rubber are shown in Table 14. As can be seen from Table 14, the antiozonant A1 has a good anti-ozone effect on the natural rubber, butadiene rubber and chloroprene rubber composite material, can effectively improve the ozone resistance of the vulcanized rubber, and has a good continuous anti-ozone effect.

[0059] Table 14: Properties of natural rubber, butadiene rubber and chloroprene rubber vulcanizates

[0060] Application Example 8: The rubber compound was prepared according to the formula shown in Table 15, and both 19# and 20# were mixed according to the conventional mixing process.

[0061] Table 15: Basic formula of rubber composite materials made of nitrile rubber and styrene butadiene rubber (parts by mass)

[0062] The rubber compound prepared according to the formula shown in Table 15 was vulcanized at 150°C for 30 minutes, and the properties of the obtained vulcanized rubber are shown in Table 16. As can be seen from Table 16, the antiozonant A2 has a good anti-ozone effect on the rubber composite material of nitrile rubber and styrene-butadiene rubber, can effectively improve the ozone resistance of the vulcanized rubber, and has a good continuous anti-ozone effect.

[0063] Table 16: Properties of vulcanized rubber blended with nitrile rubber and styrene butadiene rubber

[0064] It can be seen from the above implementation and application examples that the antiozonant containing aromatic amine functional groups and carbon-carbon double bonds provided by the present invention has a good anti-ozone effect on rubber composite materials containing carbon-carbon double bonds in the molecular chain, significantly improves the ozone resistance of vulcanized rubber, and has a good continuous anti-ozone effect.

Claims

1. An antiozonant for rubber, characterized in that: The molecular structure of the antiozonant contains both an aromatic amine functional group and a carbon-carbon double bond.

2. The antiozonant according to claim 1, characterized in that The aromatic amine functional group includes one or more of a dialkylphenylamine group, an alkylphenylamine group and a phenylamine group.

3. The antiozonant according to claim 1, characterized in that The carbon-carbon double bond is connected to two aromatic amine functional groups to form a conjugated structure.

4. The antiozonant according to claim 1, characterized in that The molecular structure of the antiozonant is as follows: ； Among them, R 1 , R 2 , R 3 , R 4 is hydrogen, or is the same or different straight or branched chain alkyl group having 1 to 8 carbon atoms.

5. The antiozonant according to claim 4, characterized in that R 1 , R 2 , R 3 , R 4 The alkyl groups are straight or branched chain alkyl groups of 1 to 3 carbon atoms, which may be the same or different.

6. A method for preparing the antiozonant according to claim 4 or 5, characterized in that: The method comprises the following steps: reacting a quaternary phosphine salt with a base to generate methylene triphenylphosphine, and subjecting the methylene triphenylphosphine to a Wittig reaction with a first raw material to obtain an antiozonant; Among them, the structural molecular formula of the first raw material is as follows: 。 7. The preparation method according to claim 6, characterized in that: The method comprises reacting a quaternary phosphine salt with a base to generate methylene triphenylphosphine, comprising the following steps: under the protection of an inert gas, preparing a quaternary phosphine salt and an organic solvent into a mixed liquid, adding a base solution with a mass concentration of 2-50wt% under stirring at 0-20° C., and continuing to stir and react for 0.1-3h to obtain a methylene triphenylphosphine mixed liquid; the quaternary phosphine salt comprises one or more of methyl triphenylphosphine chloride, methyl triphenylphosphine bromide and methyl triphenylphosphine iodide; the organic solvent comprises one or more of tetrahydrofuran, dimethylformamide, dimethyl sulfoxide and diethyl ether; the base comprises one or more of potassium tert-butoxide, sodium tert-butoxide, lithium tert-butoxide, sodium hydroxide and sodium carbonate; and the molar ratio of the base to the quaternary phosphine salt is (1-2):

1.

8. The preparation method according to claim 6, characterized in that: The method comprises the following steps: dissolving the first raw material in an organic solvent under the protection of an inert gas, mixing the first raw material with the methylene triphenylphosphine under stirring at 0-20°C, and continuing to stir and react for 4-48 hours at room temperature to reflux temperature; after the reaction is completed, pouring the reaction mixture into excess deionized water to separate an organic layer; washing the organic layer with a saturated sodium bicarbonate aqueous solution until neutral; adding anhydrous magnesium sulfate, stirring and drying; filtering; and rotary evaporating the filtrate to obtain a crude product; and separating the crude product by column chromatography, rotary evaporating, and vacuum drying at 10-40°C to constant weight to obtain an antiozonant; the organic solvent comprises one or more of tetrahydrofuran, dimethylformamide, dimethyl sulfoxide and ether; and the molar ratio of the quaternary phosphine salt to the first raw material is (1-2):

1.

9. Use of the antiozonant according to any one of claims 1 to 5 or the antiozonant prepared by the preparation method according to any one of claims 6 to 8 in ozone protection of rubber materials.

10. A rubber comprising a rubber matrix and an additive, characterized in that: The molecular chain of the rubber matrix contains carbon-carbon double bonds, and the additive comprises an antiozonant, which is the antiozonant described in any one of claims 1 to 5 or the antiozonant prepared by the preparation method described in any one of claims 6 to 8.

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