Rubber bushing sizing material and preparation method thereof

Abstract

The invention belongs to the technical field of rubber blending and vibration reduction damping, and particularly relates to a rubber bushing sizing material and a preparation method thereof. The rubber bushing material is prepared from the following raw materials in parts by mass: 60-100 parts of natural rubber, 0-40 parts of butadiene styrene rubber, 0-40 parts of butadiene rubber, 5-20 parts of ethylene propylene rubber, 20-100 parts of filler, 2-8 parts of zinc oxide, 1-5 parts of a coupling agent, 2-10 parts of a plasticizer, 1-10 parts of an active agent, 2-8 parts of a damping agent, 1-6 parts of a fatty acid processing aid, 2-6 parts of an anti-aging agent, 1-6 parts of a vulcanization accelerator, 1-5 parts of a vulcanization aid and 1-5 parts of a vulcanizing agent. The rubber bushing material prepared by the invention has the characteristics of good processing property, excellent physical and mechanical properties, low compression set, good bonding property with a metal framework and the like, and meanwhile, the product can meet the use requirements of automobile shock absorption and long fatigue life under corresponding working conditions.

Description

Technical Field

[0001] The invention belongs to the technical field of rubber and plastic vibration reduction, and in particular relates to a rubber bushing compound and a preparation method thereof. Background Art

[0002] As one of the important systems in modern cars, suspension connects the frame (or body) and the axle (or wheel) elastically, transmits all forces and moments acting between the wheel and the frame (or body), and mitigates the impact load transmitted to the frame (or body) by uneven roads, attenuates the load-bearing and system vibration caused thereby, and ensures the smooth running of the car. Its performance directly affects the ride comfort and operational stability of the vehicle. In addition to springs and shock absorbers, important force elements in the automobile suspension system also use a large number of elastic elements in the connection of its structural parts, including rubber bushings, rubber buffer blocks, hydraulic bushings and other elastic elements, such as Figure 1 shown.

[0003] The rubber bushings on the automobile suspension generally have corresponding dynamic and static stiffness and damping characteristics in different directions. When the wheel is subjected to force, the change in the six degrees of freedom of the wheel caused by the flexural deformation of the bushing is called compliance; suspension elastic kinematics refers to considering the elastic effect of the bushing and studying the influence of the relationship between the wheel alignment parameters and the wheel runout. The elastic kinematic characteristics of the suspension directly affect the handling stability of the car, and the two are coupled motions. In order to obtain the best multi-motion characteristics, the compliance characteristics should be fully considered when designing the handling stability. Since the bushing has significant nonlinear viscoelastic characteristics, its stiffness and damping performance are not only related to the frequency, but the amplitude also affects the stiffness and damping characteristics of the rubber bushing.

[0004] As a common shock-absorbing and damping material, rubber has the characteristics of easy processing, excellent performance and low price, and can be widely used in rubber bushing products. The main functions of rubber bushings are: sound insulation, vibration reduction, friction reduction, equipment wear and damage prevention, equipment life extension, noise and vibration reduction, and improved operating efficiency.

[0005] Rubber compositions are widely used in a variety of rubber bushing devices. Diolefin elastomers such as natural rubber NR, butadiene rubber BR, styrene butadiene rubber SBR, butyl rubber IIR, chloroprene rubber CR and nitrile rubber NBR are usually used. These rubbers are usually vulcanized by a heat-activated vulcanization system of sulfur and vulcanization accelerators. Rubbers made from these elastomers usually have better shock-absorbing and damping properties.

[0006] The following requirements are usually imposed on the rubber materials used in shock-absorbing bushings: (1) Compared with metal, the elastic modulus of rubber is very small and can effectively isolate vibrations; rubber is incompressible, and the viscoelasticity of rubber can produce a time delay between stress and deformation, exhibiting certain damping characteristics; (2) Due to the unique viscoelasticity of rubber materials, they can be used for vehicle noise reduction; (3) After vulcanization, they can easily bond with metal, and rubber bushings are small in size, light in weight, and have a mature production process; (4) They must meet the needs of elastic kinematics.

[0007] In patent CN111410774B-a high damping rubber material for automobile suspension bushings and its preparation method and application, the rubber bushing material mentioned is carbon black reinforced natural rubber and styrene-butadiene rubber, and only the mechanical properties of the material are mentioned, but the stiffness, bonding performance and fatigue resistance of the product are not involved. In patent CN108727648A-a natural rubber-styrene-butadiene rubber composite material, its preparation method and application, the filler N220 carbon black and the oleamide processing aid TR121 are mentioned. The particle size of N220 carbon black is relatively small, and it is difficult to disperse evenly in the rubber, which affects the long-term fatigue performance of the rubber material; and the oleamide processing aid is easy to migrate to the surface of the rubber material, resulting in poor adhesion between the rubber material and the metal skeleton. In patent CN108102155C-a natural rubber composition for vehicles, the pure carbon black reinforcement system and the sulfur and accelerator vulcanization system are mentioned. This combination leads to low vibration damping and poor high temperature resistance of the rubber material.

[0008] In bushing products, attention should be paid to the bonding between rubber compound and metal frame, as well as compression permanent deformation performance, heat aging resistance, torsional durability, stiffness, retention rate of static stiffness after durability and other properties. Currently, there is no preparation and research on more comprehensive high-performance bushing product performance. Summary of the invention

[0009] In view of some shortcomings of the above-mentioned prior art, the present invention provides a rubber bushing compound and a preparation method thereof. The present invention obtains a more comprehensive high-performance rubber bushing compound by making the compound have good mixing and vulcanization processing properties, high temperature resistance, dynamic fatigue performance, and excellent shock absorption and damping properties.

[0010] In order to achieve the above object, the technical solution adopted by the present invention is as follows: the rubber bushing rubber material is composed of the following in parts by mass:

[0011]

[0012] Furthermore, natural rubber is mainly solid natural rubber, and natural rubber is film and standard rubber; specifically, smoked sheet rubber, crepe sheet rubber and air-dried sheet rubber, low-viscosity constant-viscosity rubber, constant-viscosity rubber CV60, light-colored rubber, full latex, No. 5 rubber, No. 10 rubber, No. 20 rubber, No. 10 constant-viscosity rubber and No. 20 constant-viscosity rubber. As a preference: for the stability of the rubber bushing product, a standard rubber with a constant Mooney viscosity is preferred, such as a Mooney viscosity [ML1+4 (100°C)] of 60±5MU.

[0013] Furthermore, the styrene butadiene rubber is emulsion styrene butadiene rubber, such as SBR1502, SBR1712 and the like.

[0014] Furthermore, the EPDM is EPDM, including one or more of ENB-EPDM, VNB-EPDM, DCPD-EPDM and HD-EPDM. Preferably, the EPDM is ENB-EPDM, with a Mooney viscosity [ML (1+4) 125°C] of 10 to 100 MU, an ethylene content of 40 to 80%, and a third monomer content of 5 to 15%. Too low a third monomer content will result in inconsistent vulcanization speeds of the blended rubber.

[0015] Furthermore, the filler includes organic and inorganic fillers such as carbon black, white carbon black, diatomaceous earth, calcium carbonate, calcium silicate, hydrotalcite, kaolin, aramid pulp, carbon fiber, etc., and unsaturated carboxylic acid metal salts. The carbon black is a composite of carbon blacks of different particle sizes and different structural degrees; the carbon black is reinforcing carbon black, semi-reinforcing carbon black, medium-particle thermal cracking carbon black, and spray carbon black; preferably, the average particle size of the carbon black is 10 to 200 nanometers, and the nitrogen adsorption specific surface area is 10 to 150 m 2 / g, DBP oil absorption value 50~150cm 3 / 100g; the nitrogen adsorption specific surface area of ​​the white carbon black is 20 to 300m 2 / g, DBP oil absorption value 50~400cm 3 / 100g; the unsaturated carboxylic acid metal salt is zinc acrylate, zinc methacrylate, zinc dimethacrylate, magnesium methacrylate, etc.

[0016] More preferably, the filler is a combination of (carbon black or white carbon black) and an unsaturated carboxylate in a mass ratio of (40 to 70): (10 to 20).

[0017] Furthermore, the plasticizer includes petroleum plasticizers such as paraffin oil, cyclohexane oil, white oil, etc.; the coupling agent is a silane coupling agent such as vinyl silane, amino silane, epoxy silane, mercapto silane and methacryloxy silane, etc.; the fatty acid processing aid is stearic acid, zinc stearate, etc.

[0018] Furthermore, the antioxidant includes one or more combinations of amines, phenols, heterocyclics, phosphites, and protective waxes;

[0019] Further, surfactants include anionic surfactants, cationic surfactants and nonionic surfactants, etc. Anionic surfactants such as fatty acid salts, fatty alcohol ether carboxylates, alkylbenzene sulfonates, fatty alcohol sulfates, fatty alcohol ether sulfates, olefin sulfonates, fatty acid methyl ester sulfonates, amino acid surfactants, fatty alcohol ether succinates and fatty alcohol ether phosphates, etc. Cationic surfactants such as fatty amine hydrochlorides, fatty imidazoline acetates, alkyl trimethyl ammonium chlorides, alkyl dimethyl benzyl ammonium chlorides, imidazole type ammonium salts, polyquaternary ammonium salts, dialkyl dimethyl ammonium chlorides, etc. Nonionic surfactants such as fatty acid diethanolamide, polyoxyethylene ether type, fatty alcohol polyoxyethylene ether type, alkylphenol polyoxyethylene ether, carboxylic acid polyoxyethylene esters, polyol type, glycerol and pentaerythritol fatty acid esters, sucrose fatty acid esters, alkyl glycosides, fatty alcohol amides, etc.

[0020] Furthermore, nonionic surfactants are preferably selected as surfactants.

[0021] Furthermore, the damping agent includes hindered phenols and resins, wherein the resins include one or more combinations of phenolic resins, high styrene resins, petroleum resins, coumarone resins, and terpene resins.

[0022] Furthermore, the vulcanization accelerator includes one or more combinations of thiazoles, thiurams, sulfenamides, guanidines, dithiocarbamates, aldehyde amines, xanthates and thioureas.

[0023] Further, the vulcanization aid includes trimethylolpropane triacrylate (TMPTA), trimethylolpropane trimethacrylate (TMPTAMA), pentaerythritol tetraacrylate (PET4A), pentaerythritol triacrylate (PET3A), ethylene glycol diacrylate (EGDA), ethylene glycol dimethacrylate (EGDMA), N,N′-phenyl bismaleimide (PDM or HVA-2), zinc diacrylate (ZDA), zinc dimethacrylate (ZDMA), triallyl cyanurate (TAC), triallyl isocyanurate (TAIC), 1,2-polybutadiene (1,2-PBR), etc.

[0024] Furthermore, the vulcanizing agent is one or more combinations of sulfur, sulfur-containing polymer (super vulcanizing agent), peroxide, maleimide, and triazine vulcanizing agents. Preferably, the vulcanizing agent is a combination of sulfur and a sulfur-containing polymer; wherein the mass ratio of sulfur to the sulfur-containing polymer is 1-2:2-4.

[0025] The present invention selects natural rubber and a small amount of other diene rubbers, such as styrene-butadiene rubber, butadiene rubber and ethylene-propylene-diene rubber, as the base elastic material, and then selects carbon black, white carbon black and unsaturated carboxylate salts and other fillers with suitable particle size and structure for mixed filling, and finally prepares the rubber bushing material by adjusting the types and amounts of activators, processing aids, plasticizers and vulcanization systems.

[0026] The method for preparing the rubber bushing compound comprises the following steps:

[0027] (1) First, natural rubber (NR) is put into an internal mixer for plasticization and stirred at a speed of 20 to 40 r / min for 1 to 3 min. Then, the mixed rubber (styrene-butadiene rubber, butadiene rubber and ethylene-propylene-diene rubber) is added and stirred at a speed of 30 to 50 r / min for 3 to 5 min to obtain a uniformly mixed rubber.

[0028] (2) Weigh the fillers (carbon black, white carbon black and unsaturated carboxylate) and mix them evenly in a mixer. Add processing aids, antioxidants, coupling agents, damping agents, half of the fillers and zinc oxide to the blended rubber and continue stirring at a speed of 20 to 50 r / min for 4 to 8 minutes.

[0029] (3) When the mixer surface temperature reaches 70-100°C, add the remaining half of the filler, plasticizer and activator, and stir at a speed of 20-50 r / min until the mixer surface temperature reaches 110-130°C.

[0030] (4) The rubber mixture obtained in step (3) is put into an open mixing mill, the roller speed is adjusted to 20-40 r / min, and the roller distance is adjusted to 0.2-0.6 mm, and the material turning machine swings the material for 3-5 minutes; the roller distance is adjusted to 2-4 mm and the sheet is left for 16-24 hours after being discharged.

[0031] (5) The roller distance of the mixing mill is adjusted to 2-4 mm. After rolling, the vulcanization accelerator, vulcanization aid and vulcanizing agent are added again. The rubber is cut and tamped 2-5 times on the left and right sides respectively. Then, the roller distance is adjusted to 0.2-0.6 mm. The material turning machine swings the material for 3-5 minutes. The roller distance is adjusted to 0.1-0.3 mm. The triangular thinning is performed 5-6 times. Then, the roller distance is adjusted to 2-4 mm. The sheet is discharged, cooled and parked for 12-24 hours to obtain the mixed rubber material.

[0032] (6) The rubber obtained in step (5) is left to stand for 12 to 24 hours and then vulcanized to obtain the rubber bushing rubber, wherein the vulcanization pressure is 10 to 15 MPa, the vulcanization temperature is 150 to 170° C., and the vulcanization time is 5 to 15 minutes.

[0033] Vulcanization is to make the rubber reach a certain degree of cross-linking. According to different product specifications, the vulcanization pressure is selected to be 10-15MPa, the vulcanization temperature is selected to be 150-170℃, and the vulcanization time is determined according to the process positive vulcanization time t90 measured by the vulcanizer, which is usually 5-15min.

[0034] The above rubber bushing compound is used in automobile suspension shock absorption and damping.

[0035] The rubber bushing material obtained by the present invention has excellent mixing processing technology and vulcanization molding technology performance, is resistant to high and low temperatures above -60 to 90°C, is resistant to engine oil and has high damping performance. The product can meet the use of rubber bushings under harsh working conditions.

[0036] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0037] The present invention has found through experiments that adding a certain amount of EPDM rubber and an activator to the rubber material of the rubber bushing can significantly improve the stiffness retention rate of the rubber bushing product after fatigue and the heat aging resistance of the bushing rubber; and the addition of activators such as alkanolamide can act as a vulcanization accelerator and internal plasticizer in natural rubber or other diene rubber compounds filled with carbon black or white carbon black, while improving the dispersion uniformity of the filler in the rubber and the processing performance.

[0038] The present invention can significantly improve the adhesion between the rubber material and the metal skeleton without affecting the processing performance by using the unsaturated carboxylic acid metal salt and the activator in the filler in a specific dosage. The use of multifunctional acrylate can improve the high temperature vulcanization anti-reversion performance of the rubber material and the high temperature aging resistance of the product. The sulfur-containing polymer can significantly improve the heat aging resistance and dynamic fatigue performance of the rubber material by replacing part of sulfur.

[0039] The rubber bushing compound of the present invention has excellent processing performance, dynamic fatigue resistance and good shock absorption and damping performance, and the product made from the rubber bushing compound of the present invention has excellent application performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 This is a picture of a car chassis bushing. DETAILED DESCRIPTION

[0041] The present invention is further described in detail below in conjunction with examples, but the embodiments of the present invention are not limited thereto.

[0042] Among them, the tensile properties are tested according to GB / T 528-2009 "Determination of tensile stress-strain properties of vulcanized rubber or thermoplastic rubber"; the tear strength is tested according to GB / T 529-2008 "Determination of tear strength of vulcanized rubber or thermoplastic rubber"; the hot air aging properties are tested according to GB / T 3512-2014 "Hot air accelerated aging and heat resistance test of vulcanized rubber or thermoplastic rubber"; the compression permanent deformation is tested according to GB / T 7759.1-2015 "Determination of compression permanent deformation of vulcanized rubber or thermoplastic rubber Part 1: At room temperature or high temperature conditions"; the low temperature brittleness is tested according to GB / T 15256-2014 "Determination of low temperature brittleness of vulcanized rubber or thermoplastic rubber (multiple specimen method)"; the ozone resistance test is tested according to GB / T7762-2014 "Static tensile test of ozone cracking resistance of vulcanized rubber or thermoplastic rubber"; the glass transition temperature of rubber is tested according to GB / T The test is carried out in accordance with GB / T 29611-2013 "Determination of glass transition temperature of raw rubber - Differential scanning calorimetry (DSC)"; the dynamic performance loss factor tanδ of rubber is tested in accordance with GB / T 9870.2-2008 "Determination of dynamic properties of vulcanized rubber or thermoplastic rubber" at a temperature range of -30℃ to 120℃ and a frequency of 100Hz; the stiffness of rubber is tested in accordance with GB / T7759-2009 "Determination of compressive stress-strain properties of vulcanized rubber or thermoplastic rubber".

[0043] Table 1-1 Raw materials mass fractions of Example A1 series and Comparative Example B1 series

[0044]

[0045]

[0046] Remark:

[0047] ①Malaysia constant viscosity standard rubber SMR CV60, Mooney viscosity [ML1+4 (100℃)] is 60±5MU;

[0048] ② Sinopec emulsion polybutadiene styrene rubber SBR1502, Mooney viscosity [ML1+4 (100℃)] about 16.5MU, glass transition temperature -30℃;

[0049] ③ Sinopec butyl rubber BR9000, Mooney viscosity [ML1+4 (100℃)] is 45±4MU;

[0050] ④ ARLANXEO's EPDM Keltan 6950C, ethylene content is 44%, Mooney viscosity [ML1+4 (125°C)] is 65MU, and the third monomer content is 9%;

[0051] ⑤ EPDM CO 054 from ENI, Italy, ethylene content 41%,

[0052] ⑥ ARLANXEO's EPDM Keltan 2450, ethylene content is 48%, Mooney viscosity [ML1+4 (125°C)] is 28MU, third monomer content is 4.1%; Mooney viscosity [ML1+4 (125°C)] is 44MU, third monomer content is 0;

[0053] ⑦Cabot N774 carbon black, particle size 80-170 nanometers, nitrogen adsorption surface area of ​​about 25-35m 2 / g; DBP oil absorption value is about 72cm 3 / 100g;

[0054] ⑧Cabot N330 carbon black, particle size 28-36 nanometers, nitrogen adsorption surface area of ​​about 80m 2 / g; DBP oil absorption value is about 102cm 3 / 100g;

[0055] ⑨Evonik Degussa’s Ultrasil VN3GR, a granulated silica product, has a nitrogen adsorption surface area of ​​approximately 180 m 2 / g;

[0056] ⑩Zinc dimethacrylate ZDMA from Qingdao Zhongxiang Company;

[0057] Piccolyte A115 terpene resin from Pinova, USA, softening point 62-64°C;

[0058] Qixiang Chemical's super vulcanizing agent PSO-35 is a sulfur-containing polymer with a sulfur content of 35%.

[0059] Example A1-1

[0060] The method for preparing the rubber bushing compound comprises the following steps:

[0061] (1) First, natural rubber NR is put into an internal mixer for plasticization and stirred at a speed of 20 r / min for 2 min. Then, a mixed rubber such as styrene-butadiene rubber and EPDM rubber is added and stirred at a speed of 40 r / min for 3 min to obtain a uniformly mixed blend.

[0062] (2) After weighing the fillers (carbon black, white carbon black and unsaturated carboxylate), mix them evenly in a blender, then add processing aids, antioxidants, coupling agents, damping agents, half of the fillers and zinc oxide to the blended rubber, and continue stirring at a speed of 40 r / min for 4 minutes;

[0063] (3) When the mixer temperature reaches 70°C, add the remaining half of the filler, plasticizer and activator, and stir at a speed of 40 r / min until the mixer temperature reaches 110°C;

[0064] (4) The rubber mix obtained in step (3) is put into an open mixing mill, the roller speed is adjusted to 20 r / min, the roller distance is adjusted to 0.2 mm, and the material is turned over by a material turning machine for 3 minutes; the roller distance is adjusted to 2 mm and the sheet is left for 16 hours after being discharged.

[0065] (5) The roller distance of the mixing mill is adjusted to 2 mm. After rolling, the vulcanization accelerator, vulcanization aid and vulcanizing agent are added again. The rubber is cut and tamped 3 times on the left and right sides respectively. Then, the roller distance is adjusted to 0.2 mm. The material is turned over by the material turner for 3 minutes. The roller distance is adjusted to 0.1 mm. The triangular thinning is performed 6 times. Then, the roller distance is adjusted to 4 mm. The rubber is discharged, cooled and left for 12 hours to obtain the mixed rubber material.

[0066] (6) The rubber material obtained in step (5) is left to stand for 12 hours and then vulcanized to obtain the rubber bushing rubber material.

[0067] The vulcanization pressure is 15 MPa, the vulcanization temperature is 165°C, and the vulcanization time is determined according to the process positive vulcanization time t90 measured by the vulcanizer.

[0068] The obtained rubber bushing compound and product performance test are shown in Table 2-1.

[0069] Examples A1-2 and A1-3

[0070] The preparation method is the same as that of Example A1-1, except that the amount of EPDM rubber (Keltan 6950C) added in the first step is different, and the total amount of rubber is kept constant. The performance test of the obtained rubber compound product is shown in Table 2-1.

[0071] Comparative Example B1-1

[0072] The preparation method is the same as that of Example A1-1, except that no EPDM rubber is used in the natural rubber in the first step. The performance test of the obtained rubber compound product is shown in Table 2-1.

[0073] Comparative Example B1-2

[0074] The preparation method is the same as that of Example A1-1, except that 30 parts of EPDM rubber are used in the first step. The properties of the obtained rubber compound are shown in Table 2-1.

[0075] Comparative Example B1-3

[0076] The preparation method is the same as that of Example A1-1, except that EPDM rubber is used in the first step. The properties of the obtained rubber compound product are shown in Table 2-1.

[0077] Table 2-1 Rubber bushing compound and product performance test

[0078]

[0079]

[0080] Remark:

[0081] ◎Excellent

[0082] ○Good

[0083] △Qualified

[0084] × Poor

[0085] It can be seen from Table 1-1 and Table 2-1 that:

[0086] (1) Examples A1-1 to A1-3 illustrate that the performance of EPDM in an amount of 5 to 20 parts can meet the performance and use requirements. By comparing Example A1-1 with Comparative Example B1-1, the B1-1 formula does not use EPDM, and the thermal aging performance and dynamic torsion durability performance are greatly different. The static stiffness of the B1-1 rubber material changes greatly after the durability test, and the mixing process and vulcanization process performance of the rubber material are slightly poor, and the product cannot meet the use requirements. The B1-2 rubber material uses 30 parts of EPDM, and the amount used is relatively high, which makes it difficult to blend evenly with natural rubber, so the mechanical properties of the material are significantly reduced, and the durability of the product is poor, which cannot meet the use requirements. The B1-3 rubber material uses EPDM, but because it does not contain a third monomer containing double bonds, it cannot be cross-linked with natural rubber, which also causes the mechanical properties of the material and the product performance to fail to meet the use requirements.

[0087] Table 1-2 Raw materials mass fractions of Example A2, A3 series and Comparative Example B2, B3 series

[0088]

[0089] Example A2

[0090] The method for preparing the rubber bushing compound comprises the following steps:

[0091] (1) First, natural rubber NR was put into an internal mixer for plasticization and stirred at a speed of 25 r / min for 2 min. Then, butadiene rubber and ethylene propylene diene rubber were added and stirred at a speed of 40 r / min for 3 min to obtain a uniformly mixed blend.

[0092] (2) After weighing the fillers (carbon black and unsaturated carboxylate), mix them evenly in a blender, then add processing aids, antioxidants, coupling agents, damping agents, half of the fillers, and zinc oxide to the blended rubber, and continue to stir at a speed of 30 r / min for 5 min;

[0093] (3) When the mixer temperature reaches 80°C, add the remaining half of the filler, plasticizer and activator, and stir at a speed of 30 r / min until the mixer temperature reaches 115°C;

[0094] (4) The rubber mix obtained in step (3) is put into an open mixing mill, the roller speed is adjusted to 20 r / min, and the roller distance is adjusted to 0.2 mm, and the material is turned over by a material turning machine for 3 minutes; the roller distance is adjusted to 2 mm and the sheet is left for 24 hours after being discharged.

[0095] (5) The roll distance of the open mixing mill is adjusted to 2 mm. After the rolls are wrapped, the vulcanization accelerator, the auxiliary cross-linking agent (vulcanization aid) and the vulcanizing agent are added again. The rubber is tapped and tamped 3 times on the left and right sides respectively. Then, the roll distance is adjusted to 0.2 mm. The material is turned over by the material turning machine for 3 minutes. The roll distance is adjusted to 0.1 mm. The triangular thinning is performed 6 times. Then, the roll distance is adjusted to 4 mm. The sheet is discharged, cooled and parked for 12 hours to obtain the mixed rubber material.

[0096] (6) The rubber material obtained in step (5) is left to stand for 12 hours and then vulcanized to obtain the rubber bushing rubber material.

[0097] The vulcanization pressure is 15 MPa, the vulcanization temperature is 165°C, and the vulcanization time is determined according to the process positive vulcanization time t90 measured by the vulcanizer.

[0098] The obtained rubber bushing compound and product performance test are shown in Table 2-2.

[0099] Example A3-1

[0100] The method for preparing the rubber bushing compound comprises the following steps:

[0101] (1) First, natural rubber NR was put into an internal mixer for plasticization and stirred at a speed of 30 r / min for 3 min. Then, styrene-butadiene rubber and ethylene-propylene-diene rubber were added and stirred at a speed of 50 r / min for 3 min to obtain a uniformly mixed rubber.

[0102] (2) After weighing the fillers (carbon black, white carbon black and unsaturated carboxylate), mix them evenly in a blender, then add processing aids, antioxidants, coupling agents, damping agents, half of the fillers and zinc oxide to the blended rubber, and continue to stir at a speed of 50 r / min for 4 minutes;

[0103] (3) When the mixer temperature reaches 100°C, add the remaining half of the filler, plasticizer and activator, and stir at a speed of 50 r / min until the mixer temperature reaches 130°C;

[0104] (4) The rubber mixture obtained in step (3) is put into an open mixing mill, the roller speed is adjusted to 30 r / min, and the roller distance is adjusted to 0.4 mm, and the material is turned over by a material turning machine for 4 minutes; the roller distance is adjusted to 4 mm and the sheet is left for 24 hours after being discharged.

[0105] (5) The roll distance of the open mixing mill is adjusted to 4 mm. After the rolls are wrapped, the vulcanization accelerator, the auxiliary cross-linking agent (vulcanization aid) and the vulcanizing agent are added again. The rubber is tapped and pounded 4 times on the left and right sides respectively. Then, the roll distance is adjusted to 0.2 mm. The material is turned over by the material turning machine for 3 minutes. The roll distance is adjusted to 0.1 mm. The triangular thinning is performed 6 times. Then, the roll distance is adjusted to 4 mm. The sheet is discharged, cooled and parked for 12 hours to obtain the mixed rubber material.

[0106] (6) The rubber material obtained in step (5) is left to stand for 16 hours and then vulcanized to obtain the rubber bushing rubber material.

[0107] The vulcanization pressure is 15 MPa, the vulcanization temperature is 160°C, and the vulcanization time is determined according to the process positive vulcanization time t90 measured by the vulcanizer.

[0108] The obtained rubber bushing compound and product performance test are shown in Table 2-2.

[0109] Example A3-2

[0110] The preparation method of rubber bushing compound is the same as A3-1, with the following differences: the amount of active agent is 5 parts, the amount of naphthenic oil is reduced to 2 parts, and the total amount of liquid oil in the formula system is kept at 7 parts; the amount of coupling agent used with white carbon black is 1.5 parts. The obtained rubber bushing compound and product performance test are shown in Table 2-2.

[0111] Comparative Example B2-1 and Comparative Example B2-2

[0112] The preparation method is the same as A2, except that: B2-1 filler does not contain unsaturated carboxylate; B2-2 filler contains 30 parts of unsaturated carboxylate, which is a higher amount. Other operations are the same as A2. The obtained rubber bushing compound and product performance test are shown in Table 2-2.

[0113] Comparative Example B3-1

[0114] The preparation method is the same as A3-1, except that B3-1 does not add the active agent fatty acid diethanolamide in the third step, and the other operations are the same as A3-1. The obtained rubber bushing compound and product performance test are shown in Table 2-2.

[0115] Comparative Example B3-2

[0116] The preparation method is the same as A3-2, except that the 5 parts of active agent added in the third step of B3-2 is an anionic active agent sodium lauryl sulfate. The other operations are the same as A3-2. The obtained rubber bushing compound and product performance test are shown in Table 2-2.

[0117] Table 2-2 Rubber bushing compound and product performance test

[0118]

[0119]

[0120] It can be seen from Table 1-2 and Table 2-2 that:

[0121] By comparing Example A2 and Comparative Example B2-1, zinc dimethacrylate ZDMA is used in the A2 material formula, which can form ionic crosslinking points in the rubber material, so the tensile strength of the material is significantly higher than that of the B2-1 material. The dynamic durability and static stiffness retention rate of the B2-1 material after durability are poor. Moreover, because ZDMA can increase the bonding performance of rubber materials and metal materials, the product bonding performance of the B2-1 material is poor and cannot meet the performance requirements of the product.

[0122] By comparing A2 and B2-2, more zinc dimethacrylate is added to the B2-2 material, and the mechanical properties of the material, such as tensile strength, are significantly improved, but the material has a high compression value, resulting in poor durability of the product, which does not meet the product use requirements. At the same time, due to the large amount of unsaturated metal carboxylates, more ionic cross-linking bonds will be formed during the vulcanization process of the rubber material, resulting in severe adhesion between the rubber material and the metal, and poor processing performance, which cannot meet production needs.

[0123] By comparing A3-1 with B3-1, since B3-1 does not add any activator, its improvement in the dispersion performance of the filler is not significant, so its mechanical properties are lower than those of A3-1, resulting in poor durability of the product of comparison example B3-1, which cannot meet the product usage requirements.

[0124] By comparing A3-2 and B3-2, since B3-2 uses an anionic surfactant, the mechanical properties of the material and the fatigue durability of the product are poor, indicating that the effect of the surfactant on filler dispersion and improvement of rubber material performance is not as good as the non-ionic surfactant used in A3-2.

[0125] Table 1-3 Raw materials mass fractions of Example A4, A5 series and Comparative Example B4, B5 series

[0126]

[0127] Example A4

[0128] The method for preparing the rubber bushing compound comprises the following steps:

[0129] (1) First, natural rubber NR was put into an internal mixer for plasticization and stirred at a speed of 40 r / min for 1 min. Then, styrene-butadiene rubber and ethylene-propylene-diene rubber were added and stirred at a speed of 50 r / min for 5 min to obtain a uniformly mixed rubber.

[0130] (2) After weighing the fillers (carbon black, white carbon black and unsaturated carboxylate), mix them evenly in a blender, then add processing aids, antioxidants, coupling agents, damping agents, half of the fillers and zinc oxide to the blended rubber, and continue to stir at a speed of 20 r / min for 8 minutes;

[0131] (3) When the mixer temperature reaches 100°C, add the remaining half of the filler, plasticizer and activator, and stir at a speed of 45 r / min until the mixer temperature reaches 120°C;

[0132] (4) The rubber mix obtained in step (3) is put into an open mixing mill, the roller speed is adjusted to 30 r / min, the roller distance is adjusted to 0.3 mm, and the material is turned over by a material turning machine for 5 minutes; the roller distance is adjusted to 4 mm and the sheet is left for 24 hours after being discharged.

[0133] (5) The roll distance of the open mixing mill is adjusted to 4 mm. After the rolls are wrapped, the vulcanization accelerator, the auxiliary cross-linking agent (vulcanization aid) and the vulcanizing agent are added again. The rubber is cut and pounded 5 times on the left and right sides respectively. Then, the roll distance is adjusted to 0.5 mm. The material is turned over by the material turning machine for 3 minutes. The roll distance is adjusted to 0.1 mm. The triangular thinning is performed 5 times. Then, the roll distance is adjusted to 4 mm. The sheet is discharged, cooled and parked for 24 hours to obtain the mixed rubber material.

[0134] (6) The rubber obtained in step (5) is left to stand for 16 hours and then vulcanized to obtain the rubber bushing rubber, wherein the vulcanization pressure is 15 MPa, the vulcanization temperature is 170° C., and the vulcanization time is determined according to the process positive vulcanization time t90 measured by the vulcanizer.

[0135] The obtained rubber bushing compound and product performance test are shown in Table 2-3.

[0136] Example A5

[0137] The method for preparing the rubber bushing compound comprises the following steps:

[0138] (1) First, natural rubber NR was put into an internal mixer for plasticization and stirred at a speed of 40 r / min for 3 min. Then, EPDM rubber was added and stirred at a speed of 40 r / min for 5 min to obtain a uniformly mixed rubber.

[0139] (2) After weighing the fillers (carbon black, white carbon black and unsaturated carboxylate), mix them evenly in a blender, then add processing aids, antioxidants, coupling agents, damping agents, half of the fillers and zinc oxide to the blended rubber, and continue stirring at a speed of 30 r / min for 6 min;

[0140] (3) When the mixer temperature reaches 90°C, add half of the filler, plasticizer and activator and stir at a speed of 45 r / min until the mixer temperature reaches 120°C;

[0141] (4) The rubber mix obtained in step (3) is put into an open mixing mill, the roller speed is adjusted to 30 r / min, the roller distance is adjusted to 0.3 mm, and the material is turned over by a material turning machine for 5 minutes; the roller distance is adjusted to 4 mm and the sheet is left for 24 hours after being discharged.

[0142] (5) The roller distance of the open mixing mill is adjusted to 4 mm. After the rollers are wrapped, the accelerator, the co-crosslinking agent and the vulcanizing agent are added again. The rubber is tapped and pounded 5 times on the left and right sides respectively. Then, the roller distance is adjusted to 0.5 mm. The material is turned over by the material turning machine for 3 minutes. The roller distance is adjusted to 0.1 mm. The triangular thinning is performed 5 times. Then, the roller distance is adjusted to 4 mm. The sheet is discharged, cooled and parked for 24 hours to obtain the mixed rubber material.

[0143] (6) The rubber material obtained in step (5) is left to stand for 16 hours and then vulcanized to obtain the rubber bushing rubber material.

[0144] The vulcanization pressure is 15 MPa, the vulcanization temperature is 170°C, and the vulcanization time is determined according to the process positive vulcanization time t90 measured by the vulcanizer.

[0145] The obtained rubber bushing compound and product performance test are shown in Table 2-3.

[0146] Comparative Examples B4-1 and B4-2

[0147] The preparation method is the same as A4, except that B4-1 does not add the vulcanization aid PET4A in step (5). The other operations are the same as A4.

[0148] The preparation method is the same as A4, except that B4-2 adds 6 parts of vulcanization aid PET4A in step (5). Other operations are the same as A4.

[0149] The obtained rubber bushing compound and product performance test are shown in Table 2-3

[0150] Comparative Examples B5-1 and B5-2

[0151] The preparation method is the same as A5, except that B5-1 does not add the sulfur-containing polymer PSO-35 in step (5), but uses all insoluble sulfur calculated based on the sulfur content. Other operations are the same as A5.

[0152] The preparation method is the same as A5, except that in step (5), B5-2 uses all sulfur-containing polymer PSO-35 converted according to the sulfur content, and the other operations are the same as A5.

[0153] The obtained rubber bushing compound and product performance test are shown in Table 2-3

[0154] Table 2-3 Rubber bushing compound and product performance test

[0155]

[0156] It can be seen from Table 1-3 and Table 2-3 that:

[0157] By comparing Example A4 and Comparative Example B4-1, A4 uses liquid pentaerythritol tetraacrylate, which can significantly improve the material's anti-vulcanization reversion performance and high temperature aging resistance. For thick products, the material can be vulcanized at a higher temperature without excessive surface vulcanization. B4-1 does not use pentaerythritol tetraacrylate, so the material's thermal aging performance changes greatly, the static stiffness of the bushing product is too large, and the bushing product does not meet the use requirements. A large amount of vulcanization aid pentaerythritol tetraacrylate is added to the B4-2 material formula, which causes more new cross-linking systems to be triggered after the polysulfide bonds in the cross-linked network of the rubber material are broken, and the stiffness value and fatigue durability index of the product do not meet the use requirements.

[0158] By comparing Example A5 and Comparative Example B5-1, the A5 formula material uses a super vulcanizer containing a sulfur polymer and insoluble sulfur. The sulfur-containing polymer can replace part of the sulfur to form bridging crosslinking points during the vulcanization crosslinking process. The dynamic performance is equivalent to that of polysulfide crosslinking bonds, but the heat aging resistance is better than that of the bridging crosslinking points formed by polysulfide bonds. Therefore, the compression permanent deformation performance and heat aging resistance of the rubber material are significantly better than those of the B5-1 formula material. The torsional durability and static stiffness change rate of the B5-1 formula rubber bushing product are large, which does not meet the product application requirements.

[0159] Compared with A5 and B5-2, B5-2 uses sulfur-containing polymers in the vulcanizing agent, which leads to low cross-linking efficiency and degree of cross-linking of the material, large elongation and compression set value of the material. The durability and stiffness changes of the product exceed the product index requirements and do not meet the product usage requirements.

[0160] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A high performance rubber bushing compound, characterized in that: The rubber bushing rubber material is composed of the following raw materials in terms of mass fractions: The EPDM rubber is EPDM; and the filler contains unsaturated carboxylate.

2. The high performance rubber bushing compound according to claim 1, characterized in that: The natural rubber is one of film and standard rubber; the film is a mixture of one or more of smoked rubber, crepe rubber and air-dried rubber; the standard rubber is a mixture of one or more of viscose rubber, light-colored rubber, full latex, No. 5 rubber, No. 10 rubber and No. 20 rubber.

3. The high performance rubber bushing compound according to claim 1, characterized in that: The styrene butadiene rubber is emulsion polymerized styrene butadiene rubber.

4. The high performance rubber bushing compound according to claim 1, characterized in that: The EPDM rubber is specifically one of ENB-EPDM, VNB-EPDM, DCPD-EPDM and HD-EPDM.

5. The high performance rubber bushing compound according to claim 1, characterized in that: The filler is one or more of carbon black, white carbon black, diatomaceous earth, calcium carbonate, calcium silicate, hydrotalcite, kaolin, aramid pulp, and carbon fiber mixed with an unsaturated carboxylic acid metal salt; the unsaturated carboxylic acid metal salt is one of zinc acrylate, zinc methacrylate, zinc dimethacrylate, and magnesium methacrylate.

6. The high performance rubber bushing compound according to claim 1, characterized in that: The coupling agent is a silane coupling agent; the plasticizer is an oil-based plasticizer; the damper is one or more combinations of phenolic resin, high styrene resin, petroleum resin, coumarone resin, and terpene resin; the fatty acid processing aid is stearic acid; the antioxidant is one or more combinations of amines, phenols, heterocyclics, phosphites, and protective waxes.

7. The high performance rubber bushing compound according to claim 1, characterized in that: The active agent is a surfactant, specifically one or more combinations of anionic surfactants, cationic surfactants and nonionic surfactants.

8. The high performance rubber bushing compound according to claim 1, characterized in that: The vulcanization accelerator is one or more combinations of thiazoles, thiurams, sulfenamides, guanidines, dithiocarbamates, aldehyde amines, xanthates and thioureas; The vulcanization aid is one or more combinations of trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, pentaerythritol tetraacrylate, pentaerythritol triacrylate, ethylene glycol diacrylate, ethylene glycol dimethacrylate, N,N′-p-phenyl bismaleimide, triallyl cyanurate, triallyl isocyanurate, and 1,2-polybutadiene; The vulcanizing agent is a mixture of one or more of sulfur, sulfur-containing polymers, peroxides, maleimide, and triazine vulcanizing agents.

9. The high performance rubber bushing compound according to claim 1, characterized in that: The surfactant is a nonionic surfactant; the vulcanizing agent is a combination of sulfur and a sulfur-containing polymer.

10. The method for preparing the rubber bushing compound according to any one of claims 1 to 9, characterized in that: The preparation method steps are as follows: (1) First, natural rubber is put into an internal mixer for plasticization, and stirred at a speed of 20 to 40 r / min for 1 to 3 minutes, and then styrene-butadiene rubber, butadiene rubber, and ethylene-propylene-diene rubber are added, and stirred at a speed of 30 to 50 r / min for 3 to 5 minutes to obtain a uniformly mixed rubber; (2) Weigh the filler and mix it evenly in a blender; then add fatty acid processing aid, antioxidant, coupling agent, damping agent, half of the filler and zinc oxide to the blended rubber, and continue to stir at a speed of 20 to 50 r / min for 4 to 8 minutes; (3) When the internal mixer reaches 70-100°C, add the remaining half of the filler, plasticizer and surfactant, and stir at a speed of 20-50 r / min until the mixer surface temperature reaches 110-130°C; (4) putting the rubber mix obtained in step (3) into an open mill, adjusting the roller speed to 20-40 r / min, adjusting the roller distance to 0.2-0.6 mm, and turning the material over for 3-5 minutes; adjusting the roller distance to 2-4 mm, and leaving the sheet for 16-24 hours after it is produced; (5) The roll gap of the open mixing mill is adjusted to 2-4 mm. After the rolls are wrapped, the vulcanization accelerator, the vulcanization aid and the vulcanizing agent are added again. The rubber is cut and tamped 2-5 times on the left and right sides respectively. Then, the roll gap is adjusted to 0.2-0.6 mm. The material turning machine swings the material for 3-5 minutes. The roll gap is adjusted to 0.1-0.3 mm. The triangular wrapping is performed 5-6 times. Then, the roll gap is adjusted to 2-4 mm. The sheet is discharged, cooled and parked for 12-24 hours to obtain the mixed rubber material. (6) The mixed rubber material obtained in step (5) is left to stand for 12 to 24 hours and then vulcanized to obtain the rubber bushing rubber material; wherein the pressure of the first stage of vulcanization is 10 to 15 MPa, the vulcanization temperature is 150 to 170° C., and the vulcanization time is 5 to 15 min.

11. Application of the rubber bushing compound according to any one of claims 1 to 9 in automobile suspension shock absorption and damping.

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