CN119431915A - Zinc-free vulcanizing accelerator, rubber composition, rubber product and tire - Google Patents

Abstract

The present invention provides a zinc-free vulcanizing agent, a rubber composition, a rubber product and a tire. The zinc-free vulcanizing agent is obtained by the following preparation method: zinc oxide, stearic acid, an antioxidant and a vulcanization system drug are pre-reacted in a solvent, and after the pre-reaction, zinc removal and solvent removal are performed in sequence to obtain the zinc-free vulcanizing agent. The zinc-free vulcanizing agent contains an intermediate that is active after the pre-reaction, and the intermediate has the function of promoting vulcanization and plays the role of an early activation accelerator, so that it can partially or completely replace the role of zinc oxide in a common formula. By using the zinc-free vulcanizing agent, zinc-free rubber products can be prepared, zinc-free emissions can be achieved, and it is environmentally friendly. Moreover, through the effect of the zinc-free vulcanizing agent, the rubber composition can obtain the cross-linking density and hardness, tensile stress, hysteresis and other rubber properties close to those of zinc-containing rubber without zinc.

Description

Zinc-free vulcanization aid, rubber composition, rubber product and tire

Technical Field

The invention relates to the technical field of preparation of tread rubber, in particular to a zinc-free vulcanization aid, a rubber composition, a rubber product and a tire.

Background

In the industry at present, zinc oxide or zinc-containing auxiliary agents are indispensable in tire formulation as rubber vulcanization active agents or functional auxiliary agents. The rubber composition lacking zinc has low stress at elongation, low modulus, low hardness and low crosslinking degree, and especially if it contains no zinc oxide, the diene rubber composition containing natural rubber, isoprene rubber, butyl rubber and the like can generate reversion effect, even the rubber compound has no use value at all. Thus, in general, the zinc oxide in the diene rubber composition used in the manufacture of tires is at least 2phr.

However, zinc oxide in tires can enter the water circulation system with tire wear debris, causing environmental water pollution, both from a "sustainable" and environmental protection perspective. The European Commission 2400/73/EC Command and the SB1260 act by 2016, california, U.S. have proposed restrictions on the use of zinc or zinc oxide in tires.

Thus placing demands on zinc-free production on the tyre manufacturers. However, in the prior art, if zinc is completely removed from a diene rubber composition, the degree of crosslinking is reduced, the hardness and tensile stress of the rubber compound are reduced, hysteresis loss is increased, and the use value of a tire manufactured by using the rubber composition is greatly reduced.

In order to achieve the aim of environmental protection and ensure the performance of the tire at the same time, research and development attempts of zinc-free or low-zinc rubber compositions are carried out at home and abroad. Patent CN109369994B discloses a low zinc rubber composition, and discloses a zinc rubber composition with a content of 0.5-1 phr, which is prepared by replacing zinc oxide with nano zinc oxide with high specific surface area by taking zinc hydroxide particles as a carrier, reducing zinc usage on the basis of high activity and high dispersion, and ensuring good performance of the composition. Patent CN115678038B discloses a method for using lignin zinc salt compound to replace zinc oxide, and using the characteristic of good dispersion to achieve the purpose of reducing zinc oxide application, and applying the zinc oxide to tread rubber of tire, which can ensure wear resistance of tire, reduce rolling resistance of tire and prolong service life of tire. Both patents achieve the purpose of reducing the application by improving the dispersion of zinc, and cannot completely eliminate the harm of zinc to the environment. Patent CN102300917B discloses a rubber composition containing no zinc or less than 0.5phr of zinc and applied to tire manufacturing, which improves processability of the rubber composition due to no zinc (i.e. reducing viscosity and prolonging scorch time) by capping mercaptosilane application, and although the patent can reduce zinc usage and even contain no zinc, it needs to use specific capping mercaptosilane, which may react further to generate mercapto groups during high temperature mixing, has certain irritation and odor, and has safety problems.

Disclosure of Invention

The invention mainly aims to provide a zinc-free vulcanization aid, a rubber composition, a rubber product and a tire, so as to solve the problem that the rubber product for preparing the tire in the prior art contains zinc and has environmental pollution.

In order to achieve the aim, according to one aspect of the invention, a zinc-free vulcanizing aid is provided, which is prepared by the following preparation method that zinc oxide, stearic acid, an anti-aging agent and a vulcanizing system medicine are subjected to pre-reaction in a solvent, and after the pre-reaction, zinc removal by filtration and solvent removal are sequentially carried out, so that the zinc-free vulcanizing aid is obtained.

Further, the reaction temperature of the pre-reaction is 100-190 ℃ and the reaction time is 1-120 min;

preferably, the reaction temperature of the pre-reaction is 110-170 ℃ and the reaction time is 5-50 min.

Further, 10 to 20phr of zinc oxide is added in the pre-reaction, 5-15 phr of stearic acid, 5-15 phr of an anti-aging agent 5-15 phr of vulcanization system medicine.

Further, the solvent is selected from any one or more of butanol, octanol, N-methylpyrrolidone, octane, nonane, decane, toluene and xylene;

And/or the anti-aging agent is p-phenylenediamine anti-aging agent;

And/or the vulcanizing system medicine added in the pre-reaction comprises any one or more of vulcanizing agent and accelerator, wherein the vulcanizing agent comprises any one or more of sulfur and sulfur carrier, the accelerator comprises any one or more of sulfenamide accelerator and thiazole accelerator, and preferably, the accelerator comprises any one or more of CZ, DCBS, MBTS, MBT and TBBS.

Further, the anti-aging agent includes a compound having a structure represented by formula I:

In the formula I, R ¹ is selected from chain alkyl of C ₁-C₁₈, alicyclic alkyl of C ₃-C₁₈ or aromatic hydrocarbon of C ₆-C₁₈, R ²、R³、R⁴、R⁵ is independently selected from chain alkyl of C ₁-C₁₈, R ² and R ³ or R ⁴ and R ⁵ can also form an alicyclic ring respectively or simultaneously, R ⁶ is selected from chain alkyl of H, C ₁-C₁₈, alicyclic alkyl of C ₃-C₁₈ or aromatic hydrocarbon of C ₆-C₁₈, x=0 or 1, y=0 or 1, z=0 or 1, w=0 or 1, at least one of x and w has a value of 1, y and z has at least one value of 1.

Further, the zinc-free vulcanization assistant further comprises 50-150 phr of rubber, and the preparation method of the zinc-free vulcanization assistant comprising the rubber further comprises a first mixing or a second mixing, wherein the first mixing comprises the steps of mixing filtrate obtained after filtering and removing zinc with the rubber and then removing a solvent;

Preferably, the rubber comprises one or more of natural polymers or synthetic polymers, preferably, the rubber is selected from one or more of natural rubber, styrene-butadiene rubber, isoprene rubber, natural gutta percha, polyisoprene rubber, butadiene rubber, halogenated butyl rubber and ethylene propylene diene monomer rubber, preferably, the molecular weight of the rubber is 1 kilo-4000 ten thousand, more preferably 5 kilo-3000 ten thousand, and still more preferably 1 ten thousand-800 ten thousand.

Preferably, the rubber comprises a diene rubber of the structure of formula II:

Wherein a, b, c, d, e and f are each independently integers of 0 or more, and a, b, c, d, e and f are not simultaneously 0.

According to another aspect of the present application, there is provided a rubber composition comprising an elastomer, a filler and a zinc-free vulcanization aid, the zinc-free vulcanization aid being any one of the zinc-free vulcanization aids described above.

Further, the filler comprises any one or more of carbon-based filler, silicon-based filler, carbon-silicon dual-phase filler and clay;

preferably, the specific surface area of the filler is 10 to 500m ²/g, more preferably 30 to 300m ²/g, still more preferably 50 to 300m ²/g.

Further, the rubber composition comprises 100phr of elastomer, 20phr to 170phr of filler, and 10 phr to 50phr of zinc-free vulcanization aid;

Preferably, the rubber composition comprises 3-30 parts of other auxiliary agents, wherein the other auxiliary agents are selected from any one or more of resin, operating oil, vulcanizing agent and silane coupling agent.

According to still another aspect of the present application, there is provided a rubber article prepared from a rubber composition comprising the rubber composition of any one of the above.

According to still another aspect of the present application, there is provided a tire containing the rubber article described above.

By applying the technical scheme of the invention, the zinc-free vulcanization assistant contains an active intermediate generated by pre-reacting an anti-aging agent with a vulcanization system medicine under the catalysis of zinc oxide and stearic acid, and the intermediate has the function of promoting vulcanization and plays a role of activating the accelerator in advance, so that the zinc-free vulcanization assistant can partially or completely replace the zinc oxide in a common formula. The zinc-free vulcanization aid can be used for preparing zinc-free rubber products, realizes zinc-free emission, is environment-friendly, and can obtain the rubber material performances of crosslinking density, hardness, stretching stress, hysteresis and the like close to those of zinc-containing rubber under the condition of no zinc.

Detailed Description

It should be noted that, without conflict, the embodiments of the present application and features of the embodiments may be combined with each other. The present application will be described in detail with reference to examples.

As analyzed by the background art of the present application, the prior art has the problem that the rubber products for preparing tires contain zinc and have environmental pollution, and the lack of zinc in the existing tire rubber formula can cause the great reduction of the rubber performance, so that the use requirement is difficult to meet. In order to solve the problem, the application provides a zinc-free vulcanization aid, a rubber composition, a rubber product and a tire.

According to an exemplary embodiment of the application, a zinc-free vulcanizing aid is provided, which is prepared by a preparation method of zinc oxide, stearic acid, an anti-aging agent and a vulcanizing system medicine in a solvent for pre-reaction, and filtering and removing zinc and the solvent sequentially after the pre-reaction to obtain the zinc-free vulcanizing aid.

The zinc-free vulcanization assistant contains an active intermediate generated by pre-reacting an anti-aging agent with a vulcanization system medicine under the catalysis of zinc oxide and stearic acid, and the intermediate has the function of promoting vulcanization and plays a role of activating the accelerator in advance, so that the zinc-free vulcanization assistant can partially or completely replace the zinc oxide in a common formula. The zinc-free vulcanization aid can be used for preparing zinc-free rubber products, realizes zinc-free emission, is environment-friendly, and can obtain the rubber material performances of crosslinking density, hardness, stretching stress, hysteresis and the like close to those of zinc-containing rubber under the condition of no zinc.

Taking phenylenediamine antioxidants and 2-thiobenzothiazole vulcanization system medicines as examples, the reaction generated in the pre-reaction is shown in the following reaction equation, and the generated active intermediate has the effect of promoting vulcanization.

In some embodiments of the present application, the reaction temperature of the pre-reaction is 100-190 ℃ and the reaction time is 1-120 min, so that the reaction of the anti-aging agent and the vulcanization system medicine can be promoted, and the generated pre-reaction product has a better vulcanization promoting effect, which is favorable for further improving the performance of the rubber composition containing the pre-reaction product. Preferably, the reaction temperature of the pre-reaction is 110-170 ℃, such as 120 ℃, 130 ℃, 140 ℃, 150 ℃, 160 ℃ or 170 ℃, and the pre-reaction is more effective, preferably, the reaction time of the pre-reaction is 5-50 min, such as 10min, 15min, 20min, 25min, 30min, 35min, 40min, 45min or 50min.

The proportion of zinc oxide, stearic acid, an anti-aging agent and a vulcanization system drug added in the pre-reaction can be set according to the proportion of each corresponding component in the existing formula. In some typical embodiments of the application, 10-20 phr of zinc oxide, 5-15 phr of stearic acid, 5-15 phr of anti-aging agent and 5-15 phr of vulcanization system medicine are added in the pre-reaction, and the prepared zinc-free vulcanization assistant has more remarkable promotion effect on improving the crosslinking density and sizing material performance of the composition.

In some embodiments of the application, the anti-aging agent in the pre-reaction described above is a para-phenylenediamine anti-aging agent, for example, any one or more of 4020 (6 PPD), 4010NA (IPPD), and 7 PPD.

In some preferred embodiments of the present application, the anti-aging agent of the zinc-free vulcanization assistant is an environment-friendly p-phenylenediamine anti-aging agent, which has a better effect and is more environment-friendly, and has the following structural formula:

Wherein R ¹ is selected from the group consisting of a chain hydrocarbon group of C ₁-C₁₈, an alicyclic hydrocarbon group of C ₃-C₁₈ and an aromatic hydrocarbon group of C ₆-C₁₈, R ²、R³、R⁴、R⁵ are each independently selected from the group consisting of a chain hydrocarbon group of C ₁-C₁₈, R ² and R ³ or R ⁴ and R ⁵ may also independently or simultaneously form an alicyclic ring, R ⁶ is selected from the group consisting of a chain hydrocarbon group of H, C ₁-C₁₈, an alicyclic hydrocarbon group of C ₃-C₁₈ and an aromatic hydrocarbon group of C ₆-C₁₈, x=0 or 1, y=0 or 1, z=0 or 1, w=0 or 1, and at least one of x and w has a value of 1, y and z has at least one value of 1.

In some embodiments of the present application, the sulfiding system chemicals added in the pre-reaction include any one or more of a sulfiding agent and an accelerator. In other embodiments of the present application, the curing system drug added in the pre-reaction is any one or more of accelerators, and the curing agent is added during the preparation of the rubber article. Preferably, the vulcanizing agent includes any one or more of sulfur and sulfur carriers.

Preferably, the accelerator includes any one or more of a sulfenamide accelerator and a thiazole accelerator. Preferably, the accelerator comprises any one or more of CZ, DCBS, MBTS, MBT and TBBS.

The zinc oxide and stearic acid added in the pre-reaction can be selected from the prior art, and the application has no special requirements.

The solvent in the pre-reaction can dissolve stearic acid, an anti-aging agent and a vulcanizing system drug which participate in the pre-reaction, does not dissolve zinc oxide, has no adverse effect on the reaction of the anti-aging agent and the vulcanizing system drug, and can be selected in the prior art. The addition amount of the solvent can be adjusted according to the solubility of the solvent to the pre-reaction raw materials, and preferably, the solvent is selected from any one or more of butanol, octanol, N-methylpyrrolidone, octane, nonane, decane, toluene and xylene, so that the solvent has good solubility to stearic acid, an anti-aging agent and a vulcanization system medicine, is convenient for subsequent separation, is favorable for pre-reaction, and improves the reaction efficiency.

Because zinc oxide is insoluble in the solvent, after the pre-reaction is finished, the zinc oxide in a product system obtained after the pre-reaction can be removed by filtration, other effective components can be remained in the filtrate, and the zinc oxide is well separated, so that zinc residues are avoided.

In some typical embodiments of the application, 50-150 phr of rubber is further included in the zinc-free vulcanization aid, and the preparation method of the zinc-free vulcanization aid comprising rubber further comprises a first mixing or a second mixing, wherein the first mixing comprises the steps of mixing filtrate obtained after zinc removal by filtration with rubber and removing solvent, and the second mixing comprises the steps of removing solvent from filtrate obtained after zinc removal by filtration and mixing with rubber. The zinc-free vulcanization aid containing rubber is a master batch type aid, and has better effect in subsequent application because of realizing dispersion in rubber, and is more beneficial to the exertion of the crosslinking density and the sizing material lifting effect of an active intermediate generated by the pre-reaction of the anti-aging agent and the vulcanization system medicine. In particular, the filtrate obtained after the filtration and the dezincification can be uniformly mixed with the rubber by a simpler method, such as stirring, and the rubber therein can be more fully and uniformly mixed with other components, and in the second mixing, the filtered dezincification product with the solvent can be mixed with the rubber by a mixing mode in the prior art, such as mixing.

Further, the rubber includes any one or more of a natural polymer or a synthetic polymer. Among them, natural polymers include, but are not limited to, natural gums, gutta percha, guayule, and the like. Synthetic polymers include, but are not limited to, those obtained by polymerizing monomers in solution (i.e., solution polymerized rubber), those obtained by polymerizing monomers in emulsion (i.e., emulsion polymerized rubber), and those obtained by polymerizing monomer entities. The solution polymerization rubber is a homo-or copolymer polymer of vinyl, propylene, butylene, pentene, hexene, heptene, diene with 4 to 7 carbon atoms or triene with 6 to 7 carbon atoms, or vinyl monomers containing other atoms or functional groups, including any one or more of silicon atoms, fluorine atoms, chlorine atoms, nitrogen atoms, oxygen atoms, sulfur atoms, ester groups, amino ester groups and cyano groups, and also includes homopolymers and copolymers containing the above monomers, including but not limited to polybutadiene, polyisoprene, styrene-butadiene rubber, ethylene-propylene rubber, butyl rubber, nitrile rubber, neoprene, silicone rubber, fluororubber, polyurethane rubber, chlorosulfonated polyethylene rubber, acrylate rubber, and the like.

The rubber in the zinc-free vulcanization assistant is preferably one or more of natural rubber, styrene-butadiene rubber, isoprene rubber, natural gutta percha, polyisoprene rubber, butadiene rubber, halogenated butyl rubber and ethylene propylene diene monomer rubber.

In some embodiments of the present application, the rubber in the zinc-free vulcanization assistant is preferably diene rubber, preferably, the diene rubber structure contains branched chains and/or side groups, and the branched chains and/or side groups contain alkenyl double bonds and/or aromatic groups.

In some embodiments of the present application, the rubber in the zinc-free vulcanization aid is a diene rubber comprising the structure of formula II;

In formula II, a, b, c, d, e and f are each independently integers of 0 or more, and a, b, c, d, e and f are not both 0.

Preferably, at least two of a, b, c, d, e and f are other than 0. Wherein the repeating units are randomly distributed.

In some preferred embodiments of the present application, the diene rubber having the structure of formula II, a, b, c are 0, d, e, f are not 0, or a, b, c are not 0, d, e, f are 0, or a, b, c, d are 0, e, f are not 0, and the diene rubber having the structure has a higher crosslink density.

Further, the sum of the number of alkenyl double bonds and aromatic groups on the side and side chains of the diene-based rubber of formula II is 15% or more, such as 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 90% or any range therebetween, of the sum of the number of alkenyl double bonds and aromatic groups of the rubber. Those skilled in the art will appreciate that the structure of formula II may contain only pendant or branched groups, or may contain only alkenyl double bonds or aromatic groups on the pendant or branched groups, and that the number of alkenyl double bonds or aromatic groups on the pendant or branched groups may be greater than 15% of the total number of all alkenyl double bonds and aromatic groups in the diene rubber molecular structure.

Preferably, the molecular weight of the structural rubber in the formula II is 10000-4000000.

Further, the structural rubber of formula II is 35% or more by weight of the diene rubber, preferably 60% or more by weight of the diene rubber, for example, the weight content of the structural rubber of formula II is 65%, 70%, 75%, 80%, 85%, 90%, 95% or 100% by weight of the diene rubber.

According to another aspect of the present application, there is provided a rubber composition comprising an elastomer, a filler and a zinc-free vulcanization aid, wherein the zinc-free vulcanization aid is any one of the zinc-free vulcanization aids described above.

The rubber composition adopts the zinc-free vulcanization assistant, wherein the anti-aging agent and the vulcanization system medicine generate an active intermediate through pre-reaction under the catalysis of zinc oxide and stearic acid, and the intermediate has the function of promoting vulcanization and plays the role of activating the accelerator in advance, so that the rubber composition can partially or completely replace the function of zinc oxide in a common formula. The zinc-free vulcanization assistant can be used for preparing zinc-free rubber products, realizes zinc-free emission, is environment-friendly, and can obtain the rubber material performances of crosslinking density, hardness, stretching stress, hysteresis and the like which are close to those of the zinc-free rubber composition under the condition of no zinc.

The elastomer in the rubber composition may be selected in the prior art, may be the same as or different from the rubber in the zinc-free vulcanization aid, and has no special requirements and will not be described here.

The filler in the rubber composition comprises any one or more of carbon-based filler, silicon-based filler, carbon-silicon dual-phase filler and clay, preferably, the specific surface area of the filler is 10-500 m ²/g, more preferably 30-300 m ²/g, still more preferably 50-300 m ²/g, and the rubber composition is beneficial to improving the sizing performance of the rubber composition.

In some exemplary embodiments of the present application, to better exert the synergistic effect of the components, the rubber composition comprises 100phr of elastomer, 20phr to 170phr of filler, and 10 phr to 50phr of zinc-free vulcanization aid. Preferably, the rubber composition comprises 100phr of elastomer, 50phr to 130phr of filler, and 20phr to 35phr of a zinc-free vulcanization aid.

The rubber composition of the present application may contain a vulcanizing agent, and the vulcanizing agent may be added as one of the vulcanization system chemicals to the pre-reaction for preparing the zinc-free vulcanization aid, or may be contained in the rubber composition alone.

In some preferred embodiments of the present application, the rubber composition includes 3 to 30 parts of other auxiliary agents selected from any one or more of resins, process oils, vulcanizing agents and silane coupling agents.

According to still another exemplary embodiment of the present application, there is provided a rubber article prepared from a rubber composition, wherein the rubber composition comprises any one of the rubber compositions described above.

The rubber product is prepared from the zinc-free rubber composition, not only realizes zinc-free emission, but also has the rubber material performances of crosslinking density, hardness, stretching stress, hysteresis and the like which are close to those of the zinc-containing rubber composition.

The method for preparing the rubber product by mixing the rubber composition can be selected from the prior art, and the application has no special requirement.

In some preferred embodiments of the application, the vulcanization system medicine added in the pre-reaction for preparing the zinc-free vulcanization aid is used as an accelerator, the zinc-free vulcanization aid is used for preparing the rubber product by (a) mixing the elastomer, the filler, the zinc-free vulcanization aid and optional other aids one or more times in a kneading manner, discharging the rubber at the mixing temperature of 125-200 ℃ to form a primary master batch, (b) carrying out one or more times of thermo-mechanical kneading on the primary master batch, maintaining the mixing temperature of 125-180 ℃ for 0-1200 s to form a secondary master batch, adding the filler, the antioxidant all at the stage one or more times if other aids are remained, and (C) carrying out mixing in an internal mixer on the secondary master batch and the vulcanization system together, wherein the mixing temperature is less than or equal to 120 ℃ to obtain the final rubber. In the method, the performance of the prepared rubber product can be further improved by adopting specific mixing conditions according to the zinc-free vulcanization assistant. Preferably, the final rubber prepared by the process is vulcanized on a flat vulcanizing machine to obtain vulcanized rubber.

According to still another exemplary embodiment of the present application, there is provided a tire containing the rubber article described above. The tire adopts the rubber product, so that the performance is better, the zinc emission can be reduced to zero or greatly, and the tire has better application prospect.

The advantageous effects that can be achieved by the present application will be further described below with reference to examples and comparative examples.

The sources or technical parameters of the raw materials or reagents used in the examples and comparative examples are as follows:

IR, green island evans new materials limited;

white carbon black, NEWSIL-MP, tin-free, is known as silicon industries, inc.;

carbon black, N234, midoak polymer materials limited in shandong;

Silane coupling agent Si69, nanjing dawn chemical Co., ltd;

SSBR, soliton petrochemical (25% styrene, 64% vinyl);

SBR, oleaginous ESBR1502 (styrene content 23.5%);

BR, qilu petrochemical BR9000 (nickel series high cis-cis 97%);

NR, xishuangbanna middling rubber, SCR5;

Stearic acid, PF1808, malaysia stand as a company, inc;

zinc oxide, large continuous zinc oxide plant;

anti-aging agent 4020, jiangsu san Orthochemistry Co., ltd;

Anti-aging agent 4010NA, shandong Shunshun chemical Co., ltd;

Anti-aging agent 7PPD, jiangsu san o chemical company, inc;

An anti-aging agent A which is synthesized by self and has the structural formula of

An anti-aging agent B which is synthesized by self and has the structural formula of

An anti-aging agent C which is synthesized by self and has the structural formula of

An anti-aging agent D which is synthesized by self and has the structural formula of

An anti-aging agent E which is synthesized by self and has the structural formula of

An anti-aging agent F which is synthesized by self and has the structural formula of

Promoter CZ, shandong Shun chemical Co., ltd;

promoter TBBS, shandong Shun chemical Co., ltd;

The accelerator MBTS is available from Korea Nakagaku Ming Co., ltd;

accelerator DPG, shandong Cheng Kogyo Co., ltd;

sulfur, wudi Chemicals, inc.

Example 1

10Phr of stearic acid, 17.5phr of zinc oxide, 10phr of antioxidant 4020 and 10phr of vulcanization accelerator TBBS are mixed in decane, the reaction is carried out for 30min at 160 ℃, the zinc oxide is removed by filtration after the room temperature is recovered, and the filtrate is dried and then mixed with 96.3phr of SSBR and 30phr of BR to obtain the zinc-free vulcanization aid;

The compounds were prepared according to the formulation in table 1, as follows:

Adding SSBR and BR into an internal mixer, kneading, adding carbon black N234 and the zinc-free vulcanization assistant, continuing kneading until the mixture is uniform, and controlling the temperature at 150-160 ℃ during kneading;

Adding sulfur, kneading, wherein the temperature during kneading is not more than 110 ℃;

and vulcanizing the obtained rubber composition to obtain vulcanized rubber, and testing the physical properties of the rubber material.

Comparative example 1

The compounds were prepared according to the formulation in table 1, as follows:

adding SSBR and BR into an internal mixer, kneading, adding carbon black N234, stearic acid, zinc oxide, an anti-aging agent 4020 and an accelerator TBBS, and continuously kneading until the materials are uniformly mixed, wherein the temperature is controlled at 150-160 ℃ during kneading;

Adding sulfur, kneading, wherein the temperature during kneading is not more than 110 ℃;

and vulcanizing the obtained rubber composition to obtain vulcanized rubber, and testing the physical properties of the rubber material.

Example 2

Mixing 10phr of stearic acid, 17.5phr of zinc oxide, 12.5phr of an anti-aging agent A and 11.5phr of a vulcanization accelerator CZ in dimethylbenzene, pre-reacting for 40 minutes at 130 ℃, filtering to remove zinc oxide after recovering room temperature, drying filtrate, and mixing with 100phr of IR to obtain a zinc-free vulcanization aid;

The compounds were prepared according to the formulation in table 1, as follows:

Adding white carbon black, si69 and the zinc-free vulcanization assistant into an internal mixer after IR kneading, and continuously kneading until the mixture is uniformly mixed, wherein the temperature is controlled at 150-160 ℃ during kneading;

adding sulfur and DPG, kneading, wherein the temperature during kneading is not more than 120 ℃;

and vulcanizing the obtained rubber composition to obtain vulcanized rubber, and testing the physical properties of the rubber material.

Comparative example 2

The compounds were prepared according to the formulation in table 1, as follows:

Adding white carbon black, si69, stearic acid, zinc oxide, an anti-aging agent A and an accelerator CZ into an internal mixer for IR kneading, and continuously kneading until the mixture is uniformly mixed, wherein the temperature is controlled at 150-160 ℃ during kneading;

adding sulfur and DPG, kneading, wherein the temperature during kneading is not more than 120 ℃;

and vulcanizing the obtained rubber composition to obtain vulcanized rubber, and testing the physical properties of the rubber material.

Zero zinc blank comparative examples 0-1 and comparative examples 0-2 were set, and unlike comparative examples 1 and 2, neither comparative examples 0-1 nor comparative examples 0-2 added zinc oxide.

Table 1 sizing formulation (Unit: phr)

The zinc content in the rubber material is measured according to SN/T2945-2011 rubber and an inductively coupled plasma atomic emission spectrometry for measuring the content of lead, cadmium, chromium, copper, manganese and zinc in products thereof, and the test result is shown in Table 2.

The rubber vulcanization characteristics were measured according to GB/T16584-1996 non-rotor vulcanizing Property for rubber, and the test results are shown in Table 3.

Physical properties (tensile strength, elongation at break, 100% elongation stress, 300% elongation stress) of the compounds were measured according to GB/T528-2009 test for tensile stress strain properties of vulcanized rubber or thermoplastic rubber, and the results are shown in Table 3.

The rubber hardness was measured according to GB/T531.1-2008 method for testing indentation hardness of vulcanized rubber or thermoplastic rubber part 1 Shore durometer (Shore hardness), and the test results are shown in Table 3.

Determination of dynamic Properties of vulcanized rubber or thermoplastic rubber according to GB/T9870.1-2006 part 1 general rule the elastic modulus of the rubber compound at 20℃was determined and the compound tan delta max was determined by means of a rotarheometer, the test results being shown in Table 3.

TABLE 2

As can be seen from the results of Table 2, the zinc content of the rubber composition containing the zinc-free vulcanization aid was comparable to that of the zero zinc blank without zinc oxide, and was significantly lower than that of the conventional zinc-containing formulation.

In table 3 and the following tables of physical property test results, for comparison, the test data of each example are index values obtained based on the corresponding comparative example having the same composition except zinc oxide, for example, in table 1, the value of MH of example 1 is the ratio of the measured value to the measured value of MH of comparative example 1, 100, and the larger the value, the higher the index.

TABLE 3 physical Property test results

From the results in Table 3, it can be demonstrated that the compounds prepared from the zinc-free rubber compositions of the present invention (examples 1, 2) have a cross-linking density, modulus, stress, hardness, mechanical properties, hysteresis properties close to those of conventional zinc-containing compounds (corresponding to examples 1,2, respectively), and can be used in rubber articles and tires.

Zinc-free vulcanizing aids numbered #3 to #9 are prepared, the amounts of the specific components involved in the preparation process are shown in the following table 4, and the process parameters are shown in the following table 5. The preparation process includes mixing stearic acid, zinc oxide, antioxidant and vulcanization accelerator in solvent, pre-reacting for some time, recovering room temperature, filtering to eliminate zinc oxide, eliminating solvent from the filtrate, mixing with rubber (# 5- # 9), or eliminating solvent (# 3- # 4) after liquid phase mixing with rubber, and obtaining zinc-free vulcanization assistant. The zinc content of the zinc-free vulcanization aids #3 to #9 is 0 according to the measurement.

Zinc-free curing aids #10 to #14 were prepared in the same formulation and preparation process as example zinc-free curing aid #6, except for the pre-reaction parameters set forth in Table 5. The zinc content of the zinc-free vulcanization aids #10 to #14 is 0 according to the measurement.

TABLE 4 Table 4

TABLE 5

Examples 3 to 9 in the same manner as in example 1, comparative examples 3 to 9 were prepared as final rubber compounds and vulcanized rubber in the same manner as in comparative example 1, and the formulations thereof are shown in tables 6 and 7 below.

Table 6 sizing formulation (Unit: phr)

Table 7 sizing formulation (Unit: phr)

The formulations of examples 10 to 14 were the same as those of example 6 except that the zinc-free vulcanization aids were zinc-free vulcanization aids #10 to #14, respectively, and final rubber compounds and vulcanized rubber were prepared in the same manner as in example 1.

Examples 3 to 14 and comparative examples 3 to 9 were tested in the same test method as in example 1, and the results are shown in tables 8 and 9.

TABLE 8 physical Property test results

TABLE 9 physical Property test results

TABLE 10 physical Property test results

In tables 8 and 9, the rubber compound containing zinc-free vulcanization assistant (examples 3-9) prepared by the invention and the conventional zinc-containing rubber compound (corresponding to the corresponding examples 3-9 respectively) meet the requirements on the performance parameters of the rubber compound after vulcanization test, and can be applied to rubber products and tire production and manufacture. The vulcanized rubber compounds of the examples 2 and 5-14 are aged and then extracted, and the extractive solution is detected by ultra-high performance liquid chromatography-high resolution tandem mass spectrometry (UPLC-HRMS/MS), and no quinone compound is detected, so that the environment-friendly p-aniline anti-aging agents A-F used by the method do not generate high-toxic quinone conversion products in rubber residues, and the environment-friendly p-aniline anti-aging agent A-F is an environment-friendly rubber auxiliary agent.

In Table 10, when preparing the zinc-free vulcanizing aid, the higher temperature and the proper pre-reaction time are beneficial to improving the performance of the zinc-free vulcanizing aid, so that the rubber compound containing the zinc-free vulcanizing aid has better performance.

From the above description, it can be seen that the above embodiment of the present invention achieves the technical effect that the zinc-free vulcanization assistant contains an active intermediate formed by pre-reacting an anti-aging agent with a vulcanization system drug under the catalysis of zinc oxide and stearic acid, and the intermediate has the effect of promoting vulcanization and plays a role of activating the accelerator in advance, so that the zinc oxide can be partially or completely replaced in the conventional formulation. The zinc-free vulcanization aid can be used for preparing zinc-free rubber products, realizes zinc-free emission, is environment-friendly, and can obtain the rubber material performances of crosslinking density, hardness, stretching stress, hysteresis and the like close to those of zinc-containing rubber under the condition of no zinc.

The above description is only of the preferred embodiments of the present invention and is not intended to limit the present invention, but various modifications and variations can be made to the present invention by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (11)

1. A zinc-free vulcanization accelerator, characterized in that the zinc-free vulcanization accelerator is obtained by the following preparation method: zinc oxide, stearic acid, an antioxidant, and a vulcanization system chemical are pre-reacted in a solvent, and after the pre-reaction, zinc is removed by filtering and the solvent is removed in sequence to obtain the zinc-free vulcanization accelerator. 2. The zinc-free vulcanization aid according to claim 1, characterized in that the reaction temperature of the pre-reaction is 100-190°C and the reaction time is 1min-120min; Preferably, the reaction temperature of the pre-reaction is 110-170° C., and the reaction time is 5 min-50 min. 3. The zinc-free vulcanization aid according to claim 1, characterized in that 10 to 20 phr of zinc oxide, 5 to 15 phr of stearic acid, 5 to 15 phr of antioxidant, and 5 to 15 phr of vulcanization system chemicals are added into the pre-reaction. 4. The zinc-free vulcanization aid according to any one of claims 1 to 3, characterized in that the solvent is selected from any one or more of butanol, octanol, N-methylpyrrolidone, octane, nonane, decane, toluene and xylene; And/or, the antioxidant is a p-phenylenediamine antioxidant; And/or, the vulcanization system chemicals added in the pre-reaction include any one or more of vulcanizing agents and accelerators, the vulcanizing agent includes any one or more of sulfur and sulfur carriers, the accelerator includes any one or more of sulfonamide accelerators and thiazole accelerators, preferably, the accelerator includes any one or more of CZ, DCBS, MBTS, MBT and TBBS. 5. The zinc-free vulcanization aid according to claim 4, characterized in that the antioxidant comprises a compound having a structure shown in Formula I: In formula I, ^R1 is selected from a C1 _{- C18} chain hydrocarbon group, a _C3 - _C18 alicyclic hydrocarbon group or a _C6 - _C18 aromatic hydrocarbon group, ^R2 , ^R3 , ^R4 and ^R5 are each independently selected from a _C1 - _C18 chain hydrocarbon group, ^R2 and ^R3 or ^R4 and ^R5 may also separately or simultaneously form an aliphatic ring, ^R6 is selected from H, a _C1 - _C18 chain hydrocarbon group, a _C3 - _C18 alicyclic hydrocarbon group or a _C6 - _C18 aromatic hydrocarbon group; x＝0 or 1, y＝0 or 1, z＝0 or 1, w＝0 or 1, and at least one of x and w is 1, and at least one of y and z is 1. 6. The zinc-free vulcanization accelerator according to any one of claims 1 to 3, characterized in that the zinc-free vulcanization accelerator further comprises 50 to 150 phr of rubber, and the preparation method of the zinc-free vulcanization accelerator comprising the rubber further comprises a first mixing or a second mixing, wherein the first mixing comprises: mixing the filtrate obtained after filtering and removing zinc with the rubber and then removing the solvent; the second mixing comprises: removing the solvent from the filtrate obtained after filtering and removing zinc and then mixing with the rubber; Preferably, the rubber includes any one or more of natural polymers or synthetic polymers, preferably, the rubber is selected from any one or more of natural rubber, styrene-butadiene rubber, isoprene rubber, natural eucommia gum, polyisoprene rubber, butadiene rubber, halogenated butyl rubber and EPDM rubber; preferably, the molecular weight of the rubber is 1,000 to 40 million, more preferably 5,000 to 30 million, and more preferably 10,000 to 8 million; Preferably, the rubber comprises a diene rubber having a structure shown in Formula II: Wherein, a, b, c, d, e and f are each independently an integer greater than or equal to 0, and a, b, c, d, e and f are not 0 at the same time. 7. A rubber composition, characterized in that it comprises: an elastomer, a filler and a zinc-free vulcanization accelerator, wherein the zinc-free vulcanization accelerator is the zinc-free vulcanization accelerator according to any one of claims 1 to 6. 8. The rubber composition according to claim 7, characterized in that the filler comprises any one or more of a carbon-based filler, a silicon-based filler, a carbon-silicon dual-phase filler and clay; Preferably, the specific surface area of the filler is 10 to 500 m ² /g, more preferably 30 to 300 m ² /g, and even more preferably 50 to 300 m ² /g. 9. The rubber composition according to claim 7, characterized in that the rubber composition comprises 100 phr of elastomer, 20 phr to 170 phr of filler and 10 to 50 phr of zinc-free vulcanization aid; Preferably, the rubber composition comprises 3 to 30 parts of other additives, and the other additives are selected from any one or more of resin, process oil, vulcanizing agent and silane coupling agent. 10. A rubber product prepared from a rubber composition, characterized in that the rubber composition comprises the rubber composition according to any one of claims 7 to 9. 11. A tire, characterized by comprising the rubber product according to claim 10.