A wet mixed rubber containing natural rubber and preparation method thereof

Abstract

The present invention relates to the field of rubber, and provides a wet-mixed rubber containing natural rubber and a preparation method thereof, wherein the wet-mixed rubber containing natural rubber comprises the following raw materials by weight: 90-110 parts of natural rubber, 30-50 parts of filler, 2-4 parts of modified sepiolite, 3-7 parts of antioxidant, and 150-200 parts of deionized water. The wet-mixed rubber containing natural rubber provided by the present invention has good dispersibility, mechanical properties and wear resistance, and has good commercial application value.

Description

Technical Field

[0001] The invention relates to the field of rubber, and in particular to a wet mixed rubber containing natural rubber and a preparation method thereof. Background Art

[0002] The rubber industry is one of the important basic industries of the national economy. It not only provides people with light industrial rubber products such as daily necessities and medical products that are indispensable in daily life, but also provides various rubber production equipment or rubber parts to heavy industries and emerging industries such as mining, automobiles, construction, machinery, and electronics.

[0003] Mixing, as the primary and indispensable step in the preparation of rubber materials, plays a decisive role in the performance of rubber materials and is the key technology to obtain high-quality compound rubber and rubber products. It is mainly divided into dry mixing and wet mixing. At present, the widely used rubber mixing process in China is traditional dry mixing, but dry mixing has problems such as dust pollution and huge energy consumption during mixing, low mixing efficiency, and unsatisfactory dispersion effect of compounding agents. Wet mixing is to complete the mixing and dispersion of fillers and rubber in the liquid phase, which makes it possible to solve the above-mentioned problems of dry mixing.

[0004] Based on the many excellent characteristics of wet mixing, wet mixing has become an important development direction of natural rubber mixing technology. However, there are still some unresolved problems in the wet mixing process of natural rubber. For example, the aggregation of fillers such as silica itself can easily cause their sedimentation in the liquid phase, resulting in the loss of fillers during the flocculation process, which seriously affects the performance stability of the wet mixed natural rubber.

[0005] Patent CN104356444A discloses a highly wear-resistant reinforcing material for tires and a preparation method thereof. The highly wear-resistant reinforcing material is prepared from natural rubber, white carbon black, a silane coupling agent and a solvent by a wet mixing method. The strength and wear resistance of the material are effectively improved without destroying the molecular weight distribution of the natural rubber. However, the application does not solve the problem of sedimentation of white carbon black in the liquid phase due to its own aggregation, which will seriously affect the strength and wear resistance of the highly wear-resistant reinforcing material.

[0006] Therefore, there is an urgent need in the market for a wet-mixed rubber containing natural rubber with good dispersibility, mechanical properties and wear resistance. Summary of the invention

[0007] In view of the problems existing in the prior art, the present invention uses natural rubber as the main component, adds filler, modified sepiolite and antioxidant to synthesize a wet mixed rubber containing natural rubber, which has good dispersibility, mechanical properties and wear resistance.

[0008] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0009] On one hand, the present invention provides a wet-mixed rubber containing natural rubber, which comprises the following raw materials in parts by weight: 90-110 parts of natural rubber, 30-50 parts of filler, 2-4 parts of modified sepiolite, 3-7 parts of antioxidant, and 150-200 parts of deionized water.

[0010] In some embodiments of the present invention, the method for preparing the filler comprises the following steps:

[0011] 1) Mix arginine and ethylene glycol, heat to 60-80° C., stir, and obtain a liquid for later use;

[0012] 2) Add white carbon black into toluene, perform ultrasonication, add the liquid of step 1) and bis-[γ-(triethoxysilyl)propyl]tetrasulfide, heat to 75-85° C., stir, wash, and dry to obtain a filler.

[0013] In some embodiments of the present invention, in step 1), the molar ratio of arginine to ethylene glycol is 1:(5-7).

[0014] Preferably, in step 1), the molar ratio of arginine to ethylene glycol is 1:6.

[0015] In some embodiments of the present invention, in step 2), the mass ratio of white carbon black, liquid and bis-[γ-(triethoxysilyl)propyl]tetrasulfide is 1:(0.08-0.12):(0.15-0.25).

[0016] Preferably, in step 2), the mass ratio of white carbon black, liquid and bis-[γ-(triethoxysilyl)propyl]tetrasulfide is 1:0.1:0.2.

[0017] Silica gel has good high temperature resistance, mechanical properties and wear resistance. It is an important natural rubber additive. It has a good effect on improving the mechanical properties and wear resistance of natural rubber. However, due to the incompatibility between the hydrophilic silanol groups on the surface of silica gel and the non-polar properties of natural rubber, silica gel is easy to agglomerate in the natural rubber system.

[0018] The applicant used arginine and ethylene glycol as raw materials, ethylene glycol as a hydrogen bond donor, and arginine as a hydrogen bond acceptor to prepare a low eutectic solvent (liquid), and by controlling the molar ratio between arginine and ethylene glycol and the heating temperature, the prepared liquid had the characteristics of green environmental protection, low melting point and high thermal stability; further, the applicant modified silica by combining the prepared liquid with a coupling agent bis-[γ-(triethoxysilyl)propyl]tetrasulfide, and a silanization reaction occurred between the coupling agent bis-[γ-(triethoxysilyl)propyl]tetrasulfide and silica, so that the hydroxyl content on the surface of silica was reduced, the degree of networking of the filler was reduced, and the dispersibility of the filler was improved. The amino group in the liquid can promote the silanization reaction, and play a role in synergistically improving the dispersibility together with the coupling agent bis-[γ-(triethoxysilyl)propyl]tetrasulfide.

[0019] In some embodiments of the present invention, the method for preparing the modified sepiolite comprises the following steps:

[0020] (1) mixing sepiolite and oleic acid, ball-milling, and drying to obtain a product for later use;

[0021] (2) adding the product of step (1) into a hydrochloric acid aqueous solution, heating to 60-80° C., ultrasonicating, adding pyrrole, stirring, adding an ammonium persulfate aqueous solution, stirring, centrifuging, washing, and drying to obtain a modified sepiolite.

[0022] In some embodiments of the present invention, in step (1), the mass ratio of sepiolite to oleic acid is 1:(0.2-0.4).

[0023] Preferably, in step (1), the mass ratio of sepiolite to oleic acid is 1:0.3.

[0024] In some embodiments of the present invention, in step (2), the mass ratio of the product to pyrrole is 1:(0.15-0.2).

[0025] Preferably, in step (2), the mass ratio of the product to pyrrole is 1:0.18.

[0026] Because of its high surface area and microfiber properties, sepiolite can effectively adsorb and stabilize particles in the system to prevent them from settling, and can be used as a suspending agent. However, sepiolite still has the defect of being easy to agglomerate, resulting in poor dispersibility.

[0027] On the one hand, the applicant selected oleic acid as a modifier for sepiolite and modified the sepiolite by ball milling. Oleic acid can be grafted onto sepiolite through Si-O or Si-OH groups, thereby improving the lipophilicity of sepiolite, thereby improving the compatibility of the modified sepiolite in the rubber system, and the oleic acid structure can also improve the suspension stability of the modified sepiolite. Furthermore, ball milling can make the sepiolite fibers dissociate well, thereby improving the dispersibility and suspension performance of the modified sepiolite. On the other hand, the applicant uses polypyrrole to coat oleic acid and ball mill the modified sepiolite (product), which can improve the mechanical properties and conductive properties of the modified sepiolite while also opening the fiber structure of the sepiolite to a certain extent, thereby improving the suspension performance of the modified sepiolite.

[0028] In some embodiments of the present invention, the antioxidant is antioxidant 4010 or antioxidant 4020.

[0029] Another aspect of the present invention further provides a method for preparing the wet mixed rubber containing natural rubber described in the above technical solution, comprising the following steps:

[0030] The natural rubber, filler, modified sepiolite, antioxidant and deionized water are mixed, stirred at 30-50°C for 1-3 hours, demulsified and flocculated, flaked, washed, hammer milled and granulated, dehydrated and dried to obtain a wet mixed rubber containing natural rubber.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] (1) The present invention uses natural rubber as the main component, adds filler, modified sepiolite and antioxidant to synthesize a wet-mixed rubber containing natural rubber. Through the synergistic effect of the various components, the wet-mixed rubber containing natural rubber has the advantages of good dispersibility, mechanical properties and wear resistance.

[0033] (2) The present invention uses a low eutectic solvent and a coupling agent, bis-[γ-(triethoxysilyl)propyl]tetrasulfide, to modify silica, thereby synergistically improving the dispersibility of silica, thereby making the prepared wet mixed rubber have good dispersibility, mechanical properties and wear resistance.

[0034] (3) The present invention uses sepiolite as the main component, firstly selects oleic acid and ball milling to modify it, and further uses polypyrrole to coat the synthesized modified sepiolite, so that the suspension of the sepiolite is significantly improved, thereby significantly improving the dispersibility of the prepared wet mix, and improving the mechanical properties and wear resistance of the wet mix to a certain extent.

[0035] (4) The wet mixed rubber containing natural rubber prepared by the present invention has good dispersibility, mechanical properties and wear resistance, can be widely used in the rubber field, and has good commercial application value. DETAILED DESCRIPTION

[0036] The present invention will be described below in conjunction with specific embodiments. It should be noted that the following embodiments are examples of the present invention and are only used to illustrate the present invention, but not to limit the present invention. Other combinations and various modifications within the concept of the present invention may be performed without departing from the spirit or scope of the present invention.

[0037] In the following examples and comparative examples, except for fillers and modified sepiolite, the other compound monomers and related reagents used can be purchased from the market, wherein the natural rubber is natural rubber latex purchased from Shandong Gongfa Trading Co., Ltd.

[0038] Preparation Example 1

[0039] The synthetic method of filler A comprises the following steps:

[0040] 1) Mix 0.1 mol arginine and 0.6 mol ethylene glycol, heat to 70°C, and stir for 24 hours to obtain a liquid for use;

[0041] 2) Add 10 g of white carbon black to 300 ml of toluene, ultrasonicate for 20 min, add 1 g of the liquid of step 1) and 2 g of bis-[γ-(triethoxysilyl)propyl]tetrasulfide, heat to 80° C., stir for 12 h, wash with anhydrous ethanol 3 times, and dry at 60° C. for 24 h to obtain filler A.

[0042] Preparation Example 2

[0043] The specific implementation of filler B is the same as that of filler A, except that in step 1), the molar number of ethylene glycol is replaced with 0.047 mol.

[0044] Preparation Example 3

[0045] The specific implementation manner of filler C is the same as that of filler A, except that in step 1), the molar number of ethylene glycol is replaced with 0.072 mol.

[0046] Preparation Example 4

[0047] Filler D, the specific implementation manner is the same as that of filler A, except that: in step 2), the mass of the liquid is replaced with 0.6 g.

[0048] Preparation Example 5

[0049] Filler E, the specific implementation manner is the same as that of filler A, except that in step 2), the mass of bis-[γ-(triethoxysilyl)propyl]tetrasulfide is replaced with 1.2 g.

[0050] Preparation Example 6

[0051] The synthetic method of modified sepiolite A comprises the following steps:

[0052] (1) 10 g of sepiolite and 3 g of oleic acid were mixed, ball-milled at 250 r / min for 20 min, and dried at 60° C. for 12 h to obtain a product for later use;

[0053] (2) 10 g of the product of step (1) was added to 200 ml of 1 mol / L hydrochloric acid aqueous solution, heated to 70° C., ultrasonicated for 6 h, 1.8 g of pyrrole was added, stirred for 30 min, 250 ml of 10 g / L ammonium persulfate aqueous solution was added, stirred for 3 h, centrifuged, washed with anhydrous ethanol and deionized water twice each, and dried at 60° C. for 24 h to obtain modified sepiolite A.

[0054] Preparation Example 7

[0055] The specific implementation method of modified sepiolite B is the same as that of modified sepiolite A, except that in step (1), the mass of oleic acid is replaced with 1.8 g.

[0056] Preparation Example 8

[0057] The specific implementation method of modified sepiolite C is the same as that of modified sepiolite A, except that in step (2), the mass of pyrrole is replaced with 1.3 g.

[0058] Example 1

[0059] A wet mixed rubber containing natural rubber comprises the following raw materials in parts by weight: 100 parts of natural rubber, 40 parts of filler A, 3 parts of modified sepiolite A, 5 parts of antioxidant 4010 and 175 parts of deionized water.

[0060] The preparation method of the wet mixed rubber containing natural rubber in this embodiment comprises the following steps:

[0061] The natural rubber, filler A, modified sepiolite A, antioxidant 4010 and deionized water were mixed, stirred at 40°C for 2 hours, demulsified and flocculated, creped, washed with deionized water, granulated by hammer mill, dehydrated and dried at 60°C for 24 hours to obtain a wet mixed rubber containing natural rubber.

[0062] Example 2

[0063] A wet mixed rubber containing natural rubber comprises the following raw materials in parts by weight: 90 parts of natural rubber, 40 parts of filler A, 2 parts of modified sepiolite A, 3 parts of antioxidant 4020 and 150 parts of deionized water.

[0064] The preparation method of the wet mixed rubber containing natural rubber in this embodiment comprises the following steps:

[0065] The natural rubber, filler A, modified sepiolite A, antioxidant 4020 and deionized water were mixed, stirred at 30°C for 3 hours, demulsified and flocculated, creped, washed with deionized water, granulated by hammer mill, dehydrated and dried at 60°C for 24 hours to obtain a wet mixed rubber containing natural rubber.

[0066] Example 3

[0067] A wet mixed rubber containing natural rubber comprises the following raw materials in parts by weight: 110 parts of natural rubber, 40 parts of filler A, 4 parts of modified sepiolite A, 7 parts of antioxidant 4020 and 200 parts of deionized water.

[0068] The preparation method of the wet mixed rubber containing natural rubber in this embodiment comprises the following steps:

[0069] The natural rubber, filler A, modified sepiolite A, antioxidant 4020 and deionized water were mixed, stirred at 50°C for 1 hour, demulsified and flocculated, creped, washed with deionized water, granulated by hammer mill, dehydrated and dried at 60°C for 24 hours to obtain a wet mixed rubber containing natural rubber.

[0070] Example 4

[0071] A wet mixed rubber containing natural rubber comprises the following raw materials in parts by weight: 95 parts of natural rubber, 30 parts of filler A, 3 parts of modified sepiolite A, 4 parts of antioxidant 4010, and 160 parts of deionized water.

[0072] The preparation method of the wet mixed rubber containing natural rubber in this embodiment is the same as that in Example 1.

[0073] Example 5

[0074] A wet mixed rubber containing natural rubber comprises the following raw materials in parts by weight: 105 parts of natural rubber, 50 parts of filler A, 3 parts of modified sepiolite A, 6 parts of antioxidant 4020 and 180 parts of deionized water.

[0075] The preparation method of the wet mixed rubber containing natural rubber in this embodiment is the same as that in Example 1.

[0076] Example 6

[0077] This embodiment provides a wet mixed rubber containing natural rubber and a preparation method thereof. The specific implementation method is the same as that of Example 1, except that filler B replaces filler A in equal amounts.

[0078] Example 7

[0079] This embodiment provides a wet mixed rubber containing natural rubber and a preparation method thereof. The specific implementation method is the same as that of Example 1, except that filler C replaces filler A in equal amounts.

[0080] Example 8

[0081] This embodiment provides a wet mixed rubber containing natural rubber and a preparation method thereof. The specific implementation method is the same as that of Example 1, except that filler D replaces filler A in equal amounts.

[0082] Example 9

[0083] This embodiment provides a wet mixed rubber containing natural rubber and a preparation method thereof. The specific implementation method is the same as that of Example 1, except that filler E replaces filler A in equal amounts.

[0084] Example 10

[0085] This embodiment provides a wet mix rubber containing natural rubber and a preparation method thereof. The specific implementation method is the same as that of Example 1, except that modified sepiolite A is replaced by modified sepiolite B in equal amounts.

[0086] Embodiment 11

[0087] This embodiment provides a wet mix rubber containing natural rubber and a preparation method thereof. The specific implementation method is the same as that of Example 1, except that modified sepiolite C replaces modified sepiolite A in equal amounts.

[0088] Example 12

[0089] This embodiment provides a wet mixed rubber containing natural rubber and a preparation method thereof. The specific implementation method is the same as that of Example 1, except that an equal amount of white carbon black is used to replace filler A.

[0090] Comparative Example 1

[0091] This comparative example provides a wet mixed rubber containing natural rubber and a preparation method thereof. The specific implementation method is the same as that of Example 1, except that an equal amount of sepiolite is used to replace the modified sepiolite A.

[0092] Performance Testing

[0093] The dispersibility, mechanical properties and wear resistance of the wet mixed rubber containing natural rubber of the above Examples 1-12 and Comparative Example 1 were tested. The test results are shown in Table 1.

[0094] (1) Dispersibility

[0095] The dispersion level is used to represent the quality of dispersion, with level "9-10" being "very good"; level "8" being "good"; level "7" being "acceptable"; level "5-6" being "uncertain"; level "3-4" being "poor"; and level "1-2" being "very poor", referring to GB / T6030-2006.

[0096] (2) Mechanical properties

[0097] The judgment is made by testing the tensile strength and elongation at break, referring to GB / T 1701-2001.

[0098] (3) Wear resistance

[0099] The judgment is made by testing DIN wet abrasion, referring to GB / T 9867-2008.

[0100] Table 1

[0101]

[0102]

[0103] As can be seen from the data in Table 1, the wet mixed rubber containing natural rubber in Examples 1-5 of the present invention has good dispersibility, mechanical properties and wear resistance as a whole. Among them, Examples 6-9 respectively changed the addition ratio of the main components in the filler synthesis process, so that the dispersibility of the filler was not well improved, resulting in a certain degree of decrease in the dispersibility of the wet mixed rubber containing natural rubber, and a significant decrease in mechanical properties and wear resistance; Examples 10-11 changed the modification ratio of oleic acid and pyrrole to sepiolite in the modified sepiolite, so that the fiber structure of sepiolite was not completely opened, and then the dispersibility of the wet mixed rubber containing natural rubber was significantly decreased, and the mechanical properties and wear resistance decreased to a certain extent; Example 12 and Comparative Example 1 respectively selected white carbon black and sepiolite to replace filler A and modified sepiolite A in equal amounts, and the test found that the dispersibility, mechanical properties and wear resistance of the wet mixed rubber containing natural rubber all showed poor results.

[0104] The above implementation modes are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with this technology to understand the content of the present invention and implement it, and they cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A wet mix containing natural rubber, characterized in that: The wet mixed rubber containing natural rubber comprises the following raw materials by weight: 90-110 parts of natural rubber, 30-50 parts of filler, 2-4 parts of modified sepiolite, 3-7 parts of antioxidant, and 150-200 parts of deionized water; The preparation method of the filler comprises the following steps: 1) Mix arginine and ethylene glycol, heat to 60-80°C, stir, and obtain a liquid for later use; 2) adding white carbon black into toluene, ultrasonicating, adding the liquid of step 1) and bis-[γ-(triethoxysilyl)propyl]tetrasulfide, heating to 75-85° C., stirring, washing, and drying to obtain a filler; In the step 1), the molar ratio of arginine to ethylene glycol is 1:(5-7); In the step 2), the mass ratio of white carbon black, liquid and bis-[γ-(triethoxysilyl)propyl]tetrasulfide is 1:(0.08-0.12):(0.15-0.25); The preparation method of the modified sepiolite comprises the following steps: (1) Mixing sepiolite and oleic acid, ball-milling, and drying to obtain a product for later use; (2) adding the product of step (1) into a hydrochloric acid aqueous solution, heating to 60-80° C., ultrasonicating, adding pyrrole, stirring, adding an ammonium persulfate aqueous solution, stirring, centrifuging, washing, and drying to obtain a modified sepiolite; In the step (1), the mass ratio of sepiolite to oleic acid is 1:(0.2-0.4); In the step (2), the mass ratio of the product to pyrrole is 1:(0.15-0.2).

2. The wet mix containing natural rubber according to claim 1, characterized in that: The natural rubber is natural rubber latex.

3. The wet mix containing natural rubber according to claim 1, characterized in that: The antioxidant is antioxidant 4010 or antioxidant 4020.

4. A method for preparing a wet mixed rubber containing natural rubber according to any one of claims 1 to 3, characterized in that: The following steps are involved: The natural rubber, filler, modified sepiolite, antioxidant and deionized water are mixed, stirred at 30-50°C for 1-3 hours, demulsified and flocculated, flaked, washed, hammer milled and granulated, dehydrated and dried to obtain a wet mixed rubber containing natural rubber.

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