Environment-friendly belted layer rubber composition

Abstract

The invention relates to the technical field of tire rubber, and discloses an environment-friendly belted layer rubber composition. According to the rubber composition, the modified lignin is used for replacing resorcinol or resorcinol formaldehyde resin, and the modified lignin is lignin modified by glyoxal and eugenol, so that the bonding performance between the belt layer rubber composition and a steel wire can be effectively improved; consumption and use of toxic resorcinol in a belted layer formula can be effectively reduced, and related pollution problems are avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of tire rubber, and specifically, to an environmentally friendly belt layer rubber composition. Background Art

[0002] During driving, tires are subjected to huge challenges, including high loads, high temperatures, high pressures, severe road surface impacts, significant deformations, and high-frequency deformations. To cope with these harsh conditions, tires must have excellent wear resistance, high load-bearing capacity, good deformability resistance, and high-temperature aging resistance. The semi-steel radial tire meets the working performance requirements of the tire through the coordinated work of its precisely designed components, including the tread, base, sidewall, belt layer, cap ply, carcass, and inner liner. Among these components of the semi-steel radial tire, the belt layer plays a crucial role. It is usually composed of cross-arranged steel wires and belt layer rubber, which not only enhances the overall strength of the tire, but also improves wear resistance, handling performance, and vehicle handling stability. The presence of the belt layer is a key factor in ensuring the excellent performance of the tire.

[0003] The belt layer rubber needs to ensure good bonding between the rubber composition and the steel wire, and ensure that it is not easily separated from the steel wire due to external forces. Studies have shown that the resorcinol-methyl donor-cobalt salt system, or the resorcinol-methyl donor-silica-cobalt salt system, can effectively improve the adhesion between the belt layer rubber and the steel wire. With the continuous development of technology, the above systems are also applied by many tire companies. Due to the toxicity problem of resorcinol, tire companies have gradually started to use resorcinol formaldehyde resin to solve the adhesion problem between the belt layer rubber and the steel wire. For example, patents CN201910561432.2, CN 201910562091.0, and CN201910562443.2 use resorcinol formaldehyde resin in combination with a methyl donor and cobalt salt to prepare a cord rubber composition, but resorcinol formaldehyde resin is still a product prepared from resorcinol. In order to further reduce the use of resorcinol, it is urgent to develop a belt layer rubber composition without resorcinol and resorcinol formaldehyde resin. Summary of the Invention

[0004] In view of the deficiencies of the prior art, the present invention provides an environmentally friendly belt layer rubber composition, which does not contain resorcinol and resorcinol formaldehyde resin, ensuring the adhesion between the belt layer rubber and the steel wire while reducing the consumption of toxic resorcinol.

[0005] To achieve the above object, the present invention adopts the following technical solutions: An environmentally friendly belt layer rubber composition, the rubber composition is prepared by mixing raw materials of the following components based on 100 parts by weight of raw rubber: Rubber matrix 100 parts by weight, Carbon black 40 - 60 parts by weight, Modified lignin 1.0 - 2.0 parts by weight, Methylene donor 3 - 4.5 parts by weight, Cobalt salt 0.5 - 1.5 parts by weight, Vulcanizing agent 6.0 - 8.0 parts by weight, Accelerator 0.5 - 1.5 parts by weight; The modified lignin is lignin modified with glyoxal and eugenol.

[0006] Preferably, the rubber composition is prepared by mixing raw materials of the following components based on 100 parts by weight of raw rubber: Rubber matrix 100 parts by weight, Carbon black 50 - 60 parts by weight, Modified lignin 1.4 - 1.8 parts by weight, Methylene donor 3.6 - 4.0 parts by weight, Cobalt salt 0.9 - 1.3 parts by weight, Vulcanizing agent 6.0 - 8.0 parts by weight, Accelerator 0.5 - 1.5 parts by weight, Antioxidant 2.0 - 3.0 parts by weight, Zinc oxide 7.0 - 9.0 parts by weight.

[0007] Preferably, the preparation method of the modified lignin comprises the following steps: 1) Pre - modification: React glyoxal and lignin under the condition of pH 5, the reaction temperature is 94 - 96 °C, introducing a dihydroxyethyl side chain; 2) Aryl activation: Add eugenol and continue the reaction under alkaline conditions, the reaction temperature is 108 - 112 °C, the allyl side chain undergoes self - condensation with the hydroxyethyl group to form a network structure.

[0008] This reaction system has no free formaldehyde / phenol, and can improve the wet - state adhesion performance of the rubber composition by utilizing the metal - adhesion synergistic effect of eugenol.

[0009] Preferably, the molar ratio of glyoxal, lignin, and eugenol is 4:5:1.

[0010] Preferably, the reaction time of step 1) pre - modification is 40 - 80 min.

[0011] Preferably, the reaction time for aryl activation in step 2) is 100 - 140 min.

[0012] Preferably, the methylene donor is hexamethoxymethylmelamine, and the carrier of hexamethoxymethylmelamine is silica.

[0013] Preferably, the cobalt salt is one or more of cobalt caprylate and cobalt borate.

[0014] Preferably, the cobalt salt is cobalt borate.

[0015] Preferably, the rubber matrix consists of the following rubbers: 90 - 100 parts by weight of natural rubber and 0 - 10 parts by weight of isoprene rubber.

[0016] As the vulcanizing agent, an organic peroxide or a sulfur - based vulcanizing agent can be compounded. As the organic peroxide, for example, benzoyl peroxide, dicumyl peroxide, di - tert - butyl peroxide, tert - butyl cumyl peroxide, methyl ethyl ketone peroxide, cumene hydroperoxide, 2,5 - dimethyl - 2,5 - bis(tert - butylperoxy)hexane, 2,5 - dimethyl - 2,5 - bis(benzoylperoxy)hexane, 2,5 - dimethyl - 2,5 - bis(tert - butylperoxy)hex - 3 - yne, 1,3 - bis(tert - butylperoxypropyl)benzene, di - tert - butyl peroxide diisopropylbenzene, tert - butyl peroxide benzene, 2,4 - dichlorobenzoyl peroxide, 1,1 - di - tert - butylperoxy - 3,3,5 - trimethylsiloxane, n - butyl 4,4 - di - tert - butylperoxypentanoate, etc. can be compounded. Among these organic peroxides, dicumyl peroxide, tert - butyl peroxide benzene, and di - tert - butyl peroxide diisopropylbenzene are preferred. In addition, as the sulfur - based vulcanizing agent, for example, sulfur, morpholine disulfide, etc. can be compounded.

[0017] As the vulcanization accelerator, a sulfenamide - type, thiazole - type, thiuram - type, thiourea - type, guanidine - type, dithiocarbamate - type, aldehyde - amine - type or aldehyde - ammonia - type, etc. can be compounded.

[0018] As the sulfenamide - type, for example, sulfenamide - type compounds such as CBS (N - cyclohexyl - 2 - benzothiazolylsulfenamide), TBBS (N - tert - butyl - 2 - benzothiazolylsulfenamide), N,N - dicyclohexyl - 2 - benzothiazolylsulfenamide, N - oxyethylene - 2 - benzothiazolylsulfenamide, N,N - diisopropyl - 2 - benzothiazolesulfenamide, etc. can be cited.

[0019] As the thiazole - type, for example, MBT (2 - mercaptobenzothiazole), MBTS (dibenzothiazolyl disulfide), sodium salt, zinc salt, copper salt, cyclohexylamine salt of 2 - mercaptobenzothiazole, 2 - (2,4 - dinitrophenyl)mercaptobenzothiazole, 2 - (2,6 - diethyl - 4 - morpholinothio)benzothiazole, etc. can be cited.

[0020] As for the thiuram series, for example, TMTD (tetramethylthiuram disulfide), tetraethylthiuram disulfide, tetramethylthiuram monosulfide, dipentamethylenethiuram disulfide, dipentamethylenethiuram monosulfide, dipentamethylenethiuram tetrasulfide, dipentamethylenethiuram hexasulfide, tetrabutylthiuram disulfide, pentamethylenethiuram tetrasulfide, etc. can be cited.

[0021] As for the thiourea series, for example, thiourea compounds such as thiocarbamide, diethylthiourea, dibutylthiourea, trimethylthiourea, di-o-tolylthiourea, etc. can be cited.

[0022] As for the guanidine series, for example, guanidine compounds such as diphenylguanidine, di-o-tolylguanidine, triphenylguanidine, o-tolylbiguanide, diphenylguanidine phthalate, etc. can be cited.

[0023] As for the dithiocarbamic acid series, for example, zinc ethylphenyldithiocarbamate, zinc butylphenyldithiocarbamate, sodium dimethyldithiocarbamate, zinc dimethyldithiocarbamate, zinc diethyldithiocarbamate, zinc dibutyldithiocarbamate, zinc dipentyldithiocarbamate, zinc dipropyldithiocarbamate, coordination salt of zinc pentamethylenedithiocarbamate and piperidine, zinc hexadecylisopropyldithiocarbamate, zinc octadecylisopropyldithiocarbamate, zinc dibenzyldithiocarbamate, sodium diethyldithiocarbamate, piperidine pentamethylenedithiocarbamate, selenium dimethyldithiocarbamate, tellurium diethyldithiocarbamate, cadmium dipentyldithiocarbamate, etc. can be cited.

[0024] As for the aldehyde-amine series or aldehyde-ammonia series, for example, acetaldehyde-aniline reactant, butyraldehyde-aniline condensate, hexamethylenetetramine, acetaldehyde-ammonia reactant, etc. can be cited.

[0025] The types of antioxidants are not particularly limited, and commonly used antioxidants can be used. Amines, phenols, and heterocyclic antioxidants can be cited, and they can be used alone or in combination of two or more.

[0026] As amine antioxidants, examples include N-phenyl-N'-isopropyl-p-phenylenediamine (4010NA), N-phenyl-N'-sec-butyl-p-phenylenediamine (4020), N-1,3-dimethylbutyl-N'-phenyl-p-phenylenediamine (6PPD), N-cyclohexyl-N'-phenyl-p-phenylenediamine (CPPD), the condensate of p-phenylenediamine and diphenylamine (H-8), the condensate of p-phenylenediamine and acetone (AP), 4-aminodiphenylamine (RT base), N-(1-methylheptyl)-N'-phenyl-p-phenylenediamine (7PPD), N-(1-methylheptyl)-N'-(4-chlorophenyl)-p-phenylenediamine (7PCPD), N-(1-methylheptyl)-N'-(3-chlorophenyl)-p-phenylenediamine (7MCPD), etc.

[0027] As phenolic antioxidants, examples include 2,6-di-tert-butyl-4-methylphenol (BHT), pentaerythritol tetrakis [β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (1010), tris(2,4-di-tert-butylphenyl) phosphite (168), 2-(2-hydroxy-5-methylphenyl) benzotriazole (UV-P), 2-(2-hydroxy-4-methoxyphenyl) benzotriazole (UV-9), etc.

[0028] As heterocyclic antioxidants, examples include 2-mercaptobenzimidazole (MBI), zinc 2-mercaptobenzimidazole (MBZ), 2-(2-hydroxyphenyl) benzimidazole (HPBI), 2-(2-aminophenyl) benzimidazole (APBI), 2-(2-methoxyphenyl) benzimidazole (MPBI), 2-(2-dodecyloxyphenyl) benzimidazole (DDPI), 2-(2-benzyloxyphenyl) benzimidazole (BOPI), 2-(2-phenoxyphenyl) benzimidazole (POPI), etc.

[0029] Preferably, the carbon black is high abrasion furnace black; and / or, the vulcanizing agent is insoluble sulfur; and / or, the accelerator is a sulfenamide accelerator; and / or, the antioxidant is one or a mixture of antioxidant 6PPD and antioxidant TMQ.

[0030] The beneficial effects of the present invention are as follows: By using modified lignin to replace resorcinol or resorcinol formaldehyde resin, the adhesion performance between the belt layer rubber composition and steel wire can be effectively improved, and the consumption of toxic resorcinol in the belt layer formulation can be effectively reduced, avoiding related pollution problems. Detailed implementation manners

[0031] Combined with the embodiments of the present invention, the technical solutions in the embodiments will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0032] The ingredient ratios of the rubber compositions of the examples, comparative examples and reference examples are shown in Table 1, and the unit of the raw material addition amount is parts by weight.

[0033] Table 1 Reference Ratio Comparative Example Example 1 Example 2 Example 3 Example 4 Example 5 NR 100 100 100 90 100 100 100 IR / / / 10 / / / N326 56 56 56 56 56 56 56 Zinc Oxide 8 8 8 8 8 8 8 Antioxidant 6PPD 1.5 1.5 1.5 1.5 1.5 1.5 1.5 Antioxidant TMQ 1 1 1 1 1 1 1 Resorcinol - 80*1 1.4 / / / / / / SL - 3020*2 / 1.6 / / / / / Modified Lignin / / 1.6 1.6 1.6 1.4 1.8 RA - 65*3 3.8 3.8 3.8 3.8 3.8 3.8 3．8 Cobalt Caprylate 1.1 1.1 1.1 1.1 / 1.1 1.1 Cobalt Borate / / / / 1 / / OT - 20 7 7 7 7 7 7 7 DZ 1 1 1 1 1 1 1 Sources of raw materials: 1. Resorcinol - 80: R - 80, Tongcheng New Materials Group Co., Ltd.; 2. Resorcinol formaldehyde resin: SL - 3020, Tongcheng New Materials Group Co., Ltd.; 3. Hexamethoxymethylmelamine: RA - 65, with a hexamethoxymethylmelamine content of 65% and the carrier being silica; The rest of the products are all commercially available products.

[0034] The preparation method of the modified lignin is as follows: 1) Pre - modification: React 0.8 mol of glyoxal and 1.0 mol of lignin at pH 5 and 95 °C for 1 h to introduce bis - hydroxyethyl side chains; 2) Aryl activation: Then add 0.2 mol of eugenol and continue to react at 110 °C under alkaline conditions for 2 h. The allyl side chain and the hydroxyethyl group undergo self - condensation to form a network structure.

[0035] The preparation method of the rubber composition is as follows: 1) First - stage mixing: Use a tangential - type internal mixer for mixing; add the rubber matrix, carbon black, and fine materials other than sulfur and accelerators, heat up to 130 - 175 °C, mix for 1 - 3 min, discharge the rubber and press it into sheets, and cool to room temperature to obtain the first - stage masterbatch; 2) Second - stage mixing: Use a tangential - type internal mixer for mixing; add the first - stage masterbatch, heat up to 140 - 175 °C, mix for 20 - 60 s, discharge the rubber and press it into sheets, and cool to room temperature to obtain the second - stage masterbatch; 3) Final stage mixing: Use a tangential mixer for mixing; add second-stage masterbatch, sulfur, and accelerator; heat up to 95 - 105 °C, mix for 20 - 50 s, and discharge and press into sheets.

[0036] The rubber compositions obtained from the reference ratio, comparative ratio, and examples were subjected to sheet testing. The adhesion performance between the rubber composition and steel wire was characterized by adhesion. The adhesion before aging (Group A), the adhesion after aging at 100 °C for 48 h (Group B), and the adhesion after aging in 5% brine for 7 days (Group C) were measured respectively. The higher the adhesion, the better the adhesion performance. The results are shown in Table 2.

[0037] Table 2 Reference Ratio Comparative Example Example 1 Example 2 Example 3 Example 4 Example 5 Group A 100% 102% 106% 105% 108% 105% 106% Group B 100% 103% 105% 105% 111% 104% 106% Group C 100% 102% 107% 106% 109% 105% 107% It can be observed from Table 2 that using modified lignin to replace resorcinol or resorcinol formaldehyde resin can also effectively improve the adhesion performance between the belt layer rubber composition and steel wire. Among the examples, Example 3 is the best example, indicating that the utility of cobalt borate is better than that of cobalt caprylate.

[0038] The above is the description of the embodiments of the present invention. Through the above description of the disclosed embodiments, those skilled in the art can implement or use the present invention. Various modifications to these embodiments will be obvious to those skilled in the art. The general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to these embodiments shown herein, but will conform to the widest scope consistent with the principles and novel points disclosed herein.

Claims

1. An environment-friendly belt layer rubber composition, characterized in that, The rubber composition is prepared by mixing the following raw materials based on 100 parts by weight of raw rubber: Rubber matrix: 100 parts by weight, Carbon black: 40 - 60 parts by weight, Modified lignin: 1.0 - 2.0 parts by weight, Methylene donor: 3 - 4.5 parts by weight, Cobalt salt: 0.5 - 1.5 parts by weight, Vulcanizing agent: 6.0 - 8.0 parts by weight, Accelerator: 0.5 - 1.5 parts by weight; The modified lignin is lignin modified with glyoxal and eugenol.

2. The environmentally friendly belt layer rubber composition according to claim 1, characterized in that, The rubber composition is prepared by mixing the following raw materials based on 100 parts by weight of raw rubber: Rubber matrix: 100 parts by weight, Carbon black: 50 - 60 parts by weight, Modified lignin: 1.4 - 1.8 parts by weight, Methylene donor: 3.6 - 4.0 parts by weight, Cobalt salt: 0.9 - 1.3 parts by weight, Vulcanizing agent: 6.0 - 8.0 parts by weight, Accelerator: 0.5 - 1.5 parts by weight, Antioxidant: 2.0 - 3.0 parts by weight, Zinc oxide: 7.0 - 9.0 parts by weight.

3. The environmentally friendly belt layer rubber composition according to claim 1 or 2, characterized in that, The preparation method of the modified lignin includes the following steps: 1) Pre - modification: React glyoxal and lignin under the condition of pH 5, the reaction temperature is 94 - 96 °C, introducing dihydroxyethyl side chains; 2) Aryl activation: Add eugenol and continue the reaction under alkaline conditions, the reaction temperature is 108 - 112 °C, and the allyl side chain undergoes self - condensation with the hydroxyethyl group to form a network structure.

4. An environment-friendly belt layer rubber composition according to claim 3, characterized in that, The molar ratio of glyoxal, lignin, and eugenol is 4:5:

1.

5. An environment-friendly belt layer rubber composition according to claim 3, characterized in that, The reaction time of step 1) pre - modification is 40 - 80 min; and / or, the reaction time of step 2) aryl activation is 100 - 140 min.

6. The environmentally friendly belt layer rubber composition according to claim 1 or 2, characterized in that, The methylene donor is hexamethoxymethylmelamine, and the carrier of hexamethoxymethylmelamine is silica.

7. An environmentally friendly belt layer rubber composition according to claim 1 or 2, characterized in that, The cobalt salt is one or more of cobalt caprylate and cobalt borate.

8. An environmentally friendly belt layer rubber composition according to claim 1 or 2, characterized in that, The cobalt salt is cobalt borate.

9. An environment-friendly belt layer rubber composition according to claim 1 or 2, characterized in that, The rubber matrix is composed of the following rubbers: 90 - 100 parts by weight of natural rubber, 0 - 10 parts by weight of isoprene rubber.

10. The environmentally friendly belt layer rubber composition according to claim 1 or 2, characterized in that, The carbon black is high - abrasion furnace black; and / or, the vulcanizing agent is insoluble sulfur; and / or, the accelerator is a sulfenamide accelerator; and / or, the antioxidant is one or a mixture of antioxidant 6PPD and antioxidant TMQ.