CN115124788A - High-strength high-toughness modified ethylene propylene diene monomer rubber and preparation method thereof - Google Patents

Abstract

The invention belongs to the field of rubber, and particularly relates to high-strength high-toughness modified ethylene propylene diene monomer and a preparation method thereof, wherein the high-strength high-toughness modified ethylene propylene diene monomer is prepared from the following raw materials in parts by weight: 80-95 parts of ethylene propylene diene monomer, 5-20 parts of epoxidized natural rubber, 15-60 parts of talcum powder, 5-10 parts of zinc oxide, 0.5-5 parts of stearic acid, 0-8 parts of naphthenic oil, 0-1 part of accelerator MBT, 1-3 parts of accelerator TMTD and 1.5 parts of sulfur; the magnesium oxide in the talcum powder and the epoxy group in the epoxidized natural rubber can construct a complex structure in the vulcanization process, so that the adhesive force between the rubber matrix and the talcum powder can be greatly increased; the preparation method is the same as the processing process of rubber, and is convenient for large-scale production; the vulcanization time of the high-strength high-toughness modified ethylene propylene diene monomer rubber compound is greatly shortened, and the tensile strength, the tearing strength and the elongation at break of the vulcanized rubber are greatly improved; the invention effectively increases the application range of the ethylene propylene diene monomer.

Description

A kind of high-strength and high-toughness modified EPDM rubber and preparation method thereof

technical field

The invention belongs to the field of rubber, in particular to a high-strength and high-toughness modified EPDM rubber and a preparation method thereof.

Background technique

EPDM is a copolymer of ethylene, propylene and a small amount of non-conjugated diene. EPDM rubber has lower specific gravity and excellent performance, has great tolerance, and can add a large amount of filler with little effect on its performance. Therefore, it can be widely used in automobile parts, waterproof materials for construction, wire and cable sheathing and other fields.

There are no active groups and polarities on the molecular chain of EPDM rubber, so there are some disadvantages, such as general mechanical properties, poor self-adhesion and mutual adhesion, and slow vulcanization speed of the rubber compound. Improving the mechanical strength of the material can reduce the quality of rubber products, and shortening the vulcanization time can improve the production efficiency of rubber products. At present, the prior art has not disclosed the technology of high-strength and high-toughness modified EPDM rubber.

To this end, the present invention provides a high-strength and high-toughness modified EPDM rubber and a preparation method thereof.

SUMMARY OF THE INVENTION

In order to make up for the deficiencies of the prior art and solve the above problems, the present invention proposes a high-strength and high-toughness modified EPDM rubber and a preparation method thereof.

The technical solution adopted by the present invention to solve the technical problem is as follows: a kind of high-strength and high-toughness modified EPDM rubber according to the present invention is composed of the following raw materials in parts by weight:

Preferably, the epoxidized natural rubber is ENR-50.

Preferably, the particle size of the talc powder is more than 1000 meshes.

Preferably, the accelerator I is selected from 2-thiol benzothiazole (MBT); the accelerator II is selected from N,N-tetramethyldithiodithiocarbamide (TMTD).

A preparation method of high-strength and high-toughness modified EPDM rubber, the preparation method is suitable for the above-mentioned high-strength and high-toughness modified EPDM rubber, and the preparation method comprises the following steps:

S1: heat-bake the EPDM rubber, epoxidized natural rubber and talc powder in the formula amount respectively;

S2: plasticizing the EPDM rubber and epoxidized natural rubber treated by S1 respectively,

S3: blend the EPDM rubber and epoxidized natural rubber treated by S2;

S4: add the stearic acid, zinc oxide, accelerator, talc, naphthenic oil and sulfur of the formula amount in turn, and knead to obtain a kneading colloid;

S5: Vulcanization, ready to use.

Preferably, the thermal drying in S1 refers to thermal drying at 50-60° C. for 1-3 hours.

Preferably, the plasticizing described in S2 refers to: using a two-roll open mill for plasticizing, the current roller temperature is 60-75°C, the rear roller temperature is 85°C, and the EPDM rubber treated by S1 is added for plasticizing. ; Set the temperature of the front roll of the two-roll mill to be 55-60°C, and the temperature of the rear roll to be 50-55°C. When the temperature of the mill reaches the preset temperature, add the epoxidized natural rubber treated by S1, and carry out Plasticizing.

Preferably, S3 is specifically: setting the temperature of the front roll of the two-roll mill to be 55-60°C, and the temperature of the rear roll to be 50-55°C, when the temperature of the mill reaches the preset temperature, adding the three Ethylene propylene rubber and epoxidized natural rubber are made of tamping, rolling, and triangular wrapping to make the glue evenly and continuously wrapped on the front roller, leaving an appropriate amount of accumulated glue above the roller distance. After 2-3 minutes of rolling, Turning and refining to form a smooth and gapless roll rubber.

Preferably, S4 is specifically as follows: uniformly adding the remaining ingredients of the formula along the axis of the roller in sequence, after each feeding, after all the ingredients are eaten, the left and right 3/4 knives are cut twice each, and the interval between the two knives is 20 seconds. Clock; feeding sequence: stearic acid, zinc oxide, accelerator, talcum powder, sulfur; finally cut and remove the rubber compound, adjust the roller distance to add the rubber compound thin pass, and make a triangle bag, thin pass 5 times, to obtain a mixed Refined rubber.

Preferably, in S5, the vulcanization is specifically as follows: the mixed rubber is parked for 24 hours and then vulcanized on a flat vulcanizer, the vulcanization temperature is 150-170°C, and the vulcanization time is 5-30min.

The beneficial effects of the present invention are as follows:

1. In the present invention, EPDM rubber and epoxidized natural rubber have better compatibility, and phase separation does not occur during the mixing process. The epoxy group in the epoxidized natural rubber can form a complex structure with the magnesium oxide in the talc powder, and this complex structure becomes the strong interfacial adhesion between the matrix and the talc powder in the EPDM rubber. . Each talc particle forms multiple complex structures with the rubber matrix, and the complex structures are destroyed one by one when the material is stressed, and the tensile strength, elongation at break and tear strength of the modified EPDM rubber are greatly increased. improvement.

2. The preparation method provided by the present invention shortens the vulcanization time of the modified rubber compound, but improves the fluidity of the modified rubber compound, and the tensile strength, elongation at break and tear strength of the modified rubber compound are all improved. There is a substantial improvement. This is because the complex structure in the modified EPDM protects the main chain by increasing the cross-linking density of the rubber, lowering the fracture of the main chain when subjected to external force, consuming energy to avoid stress concentration and releasing the hidden length of fracture, and improving the material's performance. strength and elongation at break. Compared with the EPDM rubber containing the same amount of talc (without epoxidized natural rubber), the modified EPDM rubber has a maximum increase of 52.4% in tear strength, a maximum increase in tensile strength of 140%, and a maximum elongation at break. Up to 190% increase.

3. Compared with the prior art, the modified EPDM rubber provided by the present invention has short vulcanization time, excellent mechanical properties, simple and practical preparation method, easy industrialization, and can be directly combined with the existing production technology of rubber products.

Description of drawings

The present invention will be further described below in conjunction with the accompanying drawings.

Fig. 1 is the strain dependence of the storage modulus (G') of the EPDM/ENR rubber compound with different talc contents in Example 1;

Fig. 2 is the strain dependence of the storage modulus (G') of the EPDM rubber compound of different talc content of Comparative Example 1;

Detailed ways

In order to make it easy to understand the technical means, creation features, achieved goals and effects of the present invention, the present invention will be further described below with reference to the specific embodiments.

Example 1

A high-strength and high-toughness modified EPDM rubber, comprising the following raw material components by weight: 90 parts of EPDM EPDM, 10 parts of epoxidized natural rubber ENR, 5 parts of zinc oxide, stearic acid 2 parts, 0.5 part of accelerator (MBT), 1.5 part of accelerator (TMTD), 1.5 part of sulfur, 10 parts, 20 parts, 30 parts and 50 parts of talc powder (5000 mesh), respectively marked as sample 1# , 2#, 3#, 4#.

Comparative Example 1

A EPDM rubber, comprising the following raw material components by weight: 100 parts of EPDM EPDM, 5 parts of zinc oxide, 2 parts of stearic acid, 0.5 part of accelerator (MBT), and accelerator (TMTD) 1.5 parts, 1.5 parts of sulfur, 10 parts, 20 parts, 30 parts and 50 parts of talc powder (5000 mesh), respectively marked as samples 5#, 6#, 7#, and 8#.

The preparation method of the above-mentioned high-strength and high-toughness modified EPDM rubber is:

S1. Put the EPDM rubber, epoxidized natural rubber, and talc powder in the formula amount into an oven to bake for 2 hours, and set the oven temperature to 55°C;

S2. Set the temperature of the front roller of the double-roll mill to 55°C and the temperature of the rear roller to 50°C. When the temperature of the mill reaches the preset temperature, add the epoxidized natural rubber and masticate through S1. The temperature of the current roll is 60～75℃, the temperature of the rear roll is 85℃, and the EPDM rubber treated by S1 is added for plasticizing;

S3. Set the temperature of the front roll of the double-roll mill to 55°C and the temperature of the back roll to 50°C. When the temperature of the mill reaches the preset temperature, add the EPDM rubber treated by S2, epoxidized natural The rubber is rolled to make the glue evenly and continuously wrapped on the front roller, and a proper amount of accumulated glue is left above the roller distance.

S4. Add various compounding agents of the formula evenly along the axis of the roller in turn. After each feeding, after all of them are eaten, the left and right 3/4 knives are cut twice each, and the interval between the two cutting knives is 20 seconds; feeding Sequence: stearic acid, zinc oxide, accelerator, talc, sulfur. Cut and remove the rubber compound, adjust the roller distance, add the rubber compound thinly, make a triangular bag, and thinly pass it 5 times to obtain the mixed rubber;

S5. After parking the mixed rubber for 24 hours, vulcanize it on a flat vulcanizing machine. The vulcanization temperature is 160°C, and the vulcanization time is t ₉₀ .

The dynamic mechanical properties of the mixed rubber samples prepared by S4 were tested with RPA3000 (High-speed Railway Company). The test conditions for strain scanning are: temperature: 60° C.; frequency: 1 Hz; strain: 0-280%. The strain dependence of dynamic mechanical properties of filled rubber is often referred to as the Payne effect. This effect is related to the dispersion of the filler and the interaction between the filler and the rubber matrix. Fig. 1 is the variation curve of the storage modulus (G') of the rubber compound of Example 1 with strain, and Fig. 2 is the variation curve of the storage modulus (G') of the rubber compound of Comparative Example 1 with the strain. The storage modulus (G') of the rubber compound of Example 1 is smaller than that of the rubber compound of Comparative Example 1, which indicates that the Payne effect of the modified EPDM rubber in Example 1 is weakened.

The isothermal vulcanization curve prepared by S5 was tested with a rubber processing analyzer (RPA3000, High Speed Rail Corporation). Tensile property test: According to the GB/T 528-2009 standard, the test size of the dumbbell-shaped sample is 2×4×20mm ³ . The test speed is 500mm/min. The data are shown in Table 1 below:

Table 1 Properties of different samples prepared in Example 1 and Comparative Example 1

It can be seen from the data in Table 1 that the positive vulcanization time (t ₉₀ ) of the materials (1#, 2#, 3#, 4#) in Example 1 is much lower than that of Comparative Example 1 (5#, 6#, 7#, 8#); the maximum torque (M _H ) of the materials (1#, 2#, 3#, 4#) in Example 1 is much lower than that of Comparative Example 1 (5#, 6#, 7#, 8#); wherein the maximum torque (M _H ) of the 3# compound is 39.4% of that of the 7# material. The tensile strength, tear strength and elongation at break of the material of Example 1 (1#, 2#, 3#, 4#) are much higher than those of Comparative Example 1 (5#, 6#, 7#) with the corresponding talc content , 8#), in which the tensile strength of 1# material is 2.4 times that of 5# material, the tear strength is 1.52 times that of 5# material, and the elongation at break is 2.77 times that of 5# material.

The foregoing has shown and described the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above-mentioned embodiments, and the descriptions in the above-mentioned embodiments and the description are only to illustrate the principle of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have Various changes and modifications fall within the scope of the claimed invention. The claimed scope of the present invention is defined by the appended claims and their equivalents.

Claims (10)

1. A high-strength high-toughness modified ethylene propylene diene monomer is characterized in that: the composition is characterized by comprising the following raw materials in parts by weight:

2. the high-strength high-toughness modified ethylene propylene diene monomer rubber as claimed in claim 1, wherein: the epoxidized natural rubber is ENR-50.

3. The high-strength high-toughness modified ethylene propylene diene monomer rubber as claimed in claim 1, wherein: the particle size of the talcum powder is more than 1000 meshes.

4. The high-strength high-toughness modified ethylene propylene diene monomer rubber as claimed in claim 1, wherein: the accelerator I is selected from 2-thiol benzothiazole (MBT); the promoter II is selected from N, N-tetramethyl dithio-amine (TMTD).

5. A preparation method of high-strength high-toughness modified ethylene propylene diene monomer, which is suitable for the high-strength high-toughness modified ethylene propylene diene monomer described in any of claims 1 to 4, and is characterized in that: the preparation method comprises the following steps:

s1: respectively carrying out heat drying on the ethylene propylene diene monomer, the epoxidized natural rubber and the talcum powder according to the formula ratio;

s2: respectively plasticating the ethylene propylene diene monomer and the epoxidized natural rubber which are treated by the S1,

s3: blending the ethylene propylene diene monomer treated by the S2 and the epoxidized natural rubber;

s4: sequentially adding stearic acid, zinc oxide, an accelerant, talcum powder, naphthenic oil and sulfur according to the formula ratio, and mixing to obtain a mixed colloid;

s5: and (4) vulcanizing to obtain the product.

6. The preparation method of the high-strength high-toughness modified ethylene propylene diene monomer according to claim 5, wherein the preparation method comprises the following steps: the baking in S1 refers to baking at 50-60 ℃ for 1-3 h.

7. The preparation method of the high-strength high-toughness modified ethylene propylene diene monomer according to claim 5, wherein the preparation method comprises the following steps: the plastication in S2 means that: plasticating by adopting a double-roller open mill, adding the ethylene propylene diene monomer treated by S1 to plasticate when the temperature of a front roller is 60-75 ℃ and the temperature of a rear roller is 85 ℃; and setting the temperature of a front roller of a double-roller open mill to be 55-60 ℃ and the temperature of a rear roller of the double-roller open mill to be 50-55 ℃, and adding the epoxidized natural rubber processed by S1 to plasticate when the temperature of the open mill reaches a preset temperature.

8. The preparation method of the high-strength high-toughness modified ethylene propylene diene monomer according to claim 5, wherein the preparation method comprises the following steps: s3 specifically includes: the method comprises the steps of setting the temperature of a front roller of a double-roller open mill to be 55-60 ℃, setting the temperature of a rear roller to be 50-55 ℃, adding ethylene propylene diene monomer and epoxidized natural rubber processed by S2 when the temperature of the open mill reaches a preset temperature, uniformly and continuously wrapping the rubber on the front roller by adopting glue smashing, rolling and triangular wrapping, reserving a proper amount of accumulated rubber above a roller distance, and rolling and turning for 2-3 minutes to form the smooth gapless roller wrapping rubber.

9. The preparation method of the high-strength high-toughness modified ethylene propylene diene monomer according to claim 5, wherein the preparation method comprises the following steps: s4 specifically includes: adding the rest raw materials according to the formula amount uniformly along the axial direction of the roller in sequence, after all the raw materials are added, cutting the raw materials twice by using a left cutter and a right cutter 3/4 respectively, wherein the interval between the two cutters is 20 seconds; the charging sequence is as follows: stearic acid, zinc oxide, accelerant, talcum powder and sulfur; and finally cutting off and taking down the rubber material, adjusting the roller distance, adding the rubber material for thin passing, and packaging in a triangular bag for thin passing for 5 times to obtain the rubber compound.

10. The preparation method of the high-strength high-toughness modified ethylene propylene diene monomer according to claim 5, wherein the preparation method comprises the following steps: in S5, the vulcanization is specifically as follows: standing the rubber compound for 24 hours, and vulcanizing on a flat vulcanizing machine at the vulcanizing temperature of 150 ℃ and 170 ℃; the vulcanization time is 5-30 min.

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