阅读说明：本技术 一种含有牺牲键的高撕裂高定伸应力的橡胶及其制备方法和应用 (Rubber containing sacrificial bonds and having high tearing strength and high stress at definite elongation, and preparation method and application thereof ) 是由 相益信 风源 宋庆平 李现府 林英 高建纲 王其来 于 2021-07-20 设计创作，主要内容包括：本发明提供了一种含有牺牲键的高撕裂高定伸应力的橡胶及其制备方法和应用,原料：异戊橡胶或者天然橡胶80-95份、环氧化天然橡胶5-20份、滑石粉15-60份、氧化锌5-10份、硬脂酸0.5-5份、环烷油0-8份、促进剂1-3份、硫磺2份。滑石粉中的氧化镁与环氧化天然橡胶中的环氧基团在硫化过程能够构筑可逆牺牲键网络,本发明制备方法,与橡胶的加工过程相同,便于大规模的生产。本发明的含有牺牲键的异戊橡胶虽然断裂伸长率略微下降,定伸应力和撕裂强度都显著提高,有效的增加了其应用范围。(The invention provides a rubber with high tearing and high stress at definite elongation containing a sacrificial bond, a preparation method and application thereof, wherein the rubber comprises the following raw materials: 80-95 parts of isoprene rubber or natural rubber, 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, 1-3 parts of accelerator and 2 parts of sulfur. The magnesium oxide in the talcum powder and the epoxy group in the epoxidized natural rubber can construct a reversible sacrificial bond network in the vulcanization process. Although the elongation at break of the isoprene rubber containing the sacrificial bonds is slightly reduced, the stress at definite elongation and the tear strength are both obviously improved, and the application range of the isoprene rubber is effectively enlarged.)

1. The rubber with high tearing and high tensile stress and containing the sacrificial bonds is characterized by comprising the following raw materials in parts by mass:

2. the rubber with high tearing strength and high tensile stress containing sacrificial bonds as claimed in claim 1, wherein the particle size of the talc powder is 1000 meshes or more.

3. High tear, high stress at elongation containing a sacrificial bond rubber according to claim 1, characterized in that the accelerator is selected from the group consisting of the accelerators 1, 2-ethylenethiourea (NA22) or N-tert-butyl-2-benzothiazolesulfenamide (NS).

4. A method for preparing a rubber with high tearing and high stress at definite elongation containing a sacrificial bond according to any of claims 1 to 3, characterized in that the method comprises the following steps:

1) respectively carrying out hot baking on the isoprene rubber or the natural rubber, the epoxidized natural rubber and the talcum powder in the formula ratio;

2) respectively plasticating the isoprene rubber or the natural rubber and the epoxidized natural rubber treated in the step 1),

3) blending the isoprene rubber or the natural rubber treated in the step 2) and the epoxidized natural rubber;

4) 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;

5) and (4) vulcanizing to obtain the product.

5. The preparation method according to claim 4, wherein the baking in step 1) is performed at 50-60 ℃ for 1-3 h.

6. The method according to claim 4 or 5, wherein the mastication in step 2) is: plasticating by adopting a double-roller open mill, wherein the temperature of a front roller is 55-60 ℃, the temperature of a rear roller is 50-55 ℃, and adding the natural rubber treated by the step 1) for plasticating.

7. The preparation method according to claim 4 or 5, wherein the step 3) is specifically: 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 ℃, and adding the isoprene rubber or the natural rubber and the epoxidized natural rubber treated in the step 2) for blending when the temperature of the open mill reaches a preset temperature.

8. The preparation method according to claim 4 or 5, wherein the step 4) is specifically: 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, naphthenic oil 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.

9. The preparation method according to claim 4 or 5, characterized in that the vulcanization of step 5) is in particular: and standing the rubber compound for 24 hours, and vulcanizing the rubber compound on a flat vulcanizing machine at the vulcanization temperature of 150 ℃ and 170 ℃ for 5-30 min.

10. Use of a high tear, high stress at elongation rubber containing sacrificial bonds according to any of claims 1 to 3 for the manufacture of rubber articles.

Technical Field

The invention belongs to the field of rubber, and particularly relates to high-tear high-stress-at-elongation rubber containing a sacrificial bond, and a preparation method and application thereof.

Background

Isoprene Rubber (IR) is a synthetic rubber, and has the same chemical structure as Natural Rubber (NR). The two rubbers are non-polar rubbers, the intermolecular force is small, and the rubber has excellent elasticity; the two materials have stress-induced crystallization phenomenon during stretching, and the material has self-reinforcing effect and shows good tensile strength. The two rubber materials have wide application in tires, seals, shock absorbers, and the like.

But the stress at definite elongation and the tearing strength of the isoprene rubber and the natural rubber are not high, and the quality of rubber products can be reduced by improving the stress at definite elongation and the tearing strength of the material. The prior art does not disclose the technology of isoprene rubber with high tearing and high stress at definite elongation at present.

Disclosure of Invention

The invention aims to provide a rubber containing a sacrificial bond and having high tearing strength and high stress at definite elongation and a preparation method thereof, and the rubber has high product modulus, high tearing strength and simple and convenient preparation method.

The invention also aims to provide application of the rubber with high tearing strength and high stress at definite elongation containing the sacrificial bonds, which is used for producing rubber products and can be directly combined with the existing production process of the rubber products.

The specific technical scheme of the invention is as follows:

a rubber containing a sacrificial bond and having high tearing and high stress at definite elongation comprises the following raw materials in parts by mass:

the rubber containing the sacrificial bonds and having high tearing and high stress at definite elongation comprises the following raw materials in parts by mass:

the particle size of the talcum powder is more than 1000 meshes;

the accelerator is selected from accelerator 1, 2-ethylene thiourea (NA22) or N-tertiary butyl-2-benzothiazole sulfonamide (NS);

the invention provides a preparation method of rubber with high tearing and high stress at definite elongation, which comprises the following steps:

1) respectively carrying out hot baking on the isoprene rubber or the natural rubber, the epoxidized natural rubber and the talcum powder in the formula ratio;

2) respectively plasticating the isoprene rubber or the natural rubber and the epoxidized natural rubber treated in the step 1),

3) blending the isoprene rubber or the natural rubber treated in the step 2) and the epoxidized natural rubber;

4) 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;

5) and (4) vulcanizing to obtain the product.

The step 1) of baking refers to baking for 1-3 hours at 50-60 ℃;

the plastication in the step 2) refers to: plasticating by adopting a double-roller open mill, wherein the temperature of a front roller is 55-60 ℃, the temperature of a rear roller is 50-55 ℃, and adding the natural rubber treated by the step 1) for plasticating.

The step 3) is specifically as follows: 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 ℃, and adding the isoprene rubber or the natural rubber and the epoxidized natural rubber treated in the step 2) for blending when the temperature of the open mill reaches a preset temperature.

The step 3) is specifically as follows: 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 the isoprene rubber or natural rubber and epoxidized natural rubber treated in the step 2) when the temperature of the open mill reaches a preset temperature, uniformly and continuously wrapping the rubber on the front roller by adopting one or more modes of rubber smashing, rolling or triangular wrapping, reserving a proper amount of stacking rubber above the roller distance, and rolling and turning for 2-3 minutes to form the smooth gapless roller wrapping rubber.

The step 4) is specifically as follows: 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, naphthenic oil 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.

Step 5) the vulcanization is specifically as follows: the mixed rubber is placed for 24 hours and then vulcanized on a flat vulcanizing machine, and the vulcanization temperature is 150 ℃ and 170 ℃. The vulcanization time is 5-30 min.

The invention provides application of isoprene rubber with high tearing strength and high stress at definite elongation, which contains a sacrificial bond, and is used for manufacturing rubber products.

The epoxidized natural rubber has better compatibility with isoprene rubber or natural rubber, and has no phase separation phenomenon in the mixing process. The epoxy group and the talcum powder in the epoxidized natural rubber are well crosslinked to form reversible sacrificial bonds in a rubber crosslinking network. Epoxy groups in the epoxidized natural rubber can form a complex structure with magnesium oxide in the talcum powder, and the complex structure constructs reversible sacrificial bonds in the isoprene rubber or the natural rubber. The reversible sacrificial bond is a sacrificial functional bond which is broken in preference to the main chain of the polymer under the action of external force and consumes energy to play a role in strengthening and toughening. The reversible sacrificial bond is formed by that under the action of external force, the bond consumes energy after being broken and can be recovered through a certain recovery time. The reversible sacrificial bond has dynamic property, can be continuously reconstructed when being damaged, and continuously consumes energy; after unloading, the cross-linking point is regenerated after a period of time, and the performance of the material is recovered. The reversible sacrificial bond is broken in preference to the main chain covalent bond in the stretching process due to low bond energy, and the consumed energy plays a role in reinforcement; the broken cross-linking points will break and reconstruct in the continuous stretching process; the breaking of the cross-linking points brings about the release of free segments and of hidden molecular chains. When the bond is broken, the non-reconstructed secondary bond short chain can be regarded as a released free chain segment, and the entropy value of the elastomer is effectively increased.

The preparation method provided by the invention reduces the vulcanization time of the rubber material, but improves the fluidity of the rubber compound, and obviously improves the tearing strength and the stress at definite elongation of the vulcanized rubber material; the elongation at break is reduced slightly, and the modulus is greatly improved. The rubber containing the sacrificial bond is the sacrificial bond constructed by the crosslinked network of the talcum powder and the epoxidized natural rubber. The sacrificial bond protects the main chain by improving the crosslinking density of the rubber, breaking the main chain before external force, consuming energy to avoid stress concentration and releasing hidden length by breaking, and improving the tearing strength and the stress at definite elongation of the material. The rubber with high tearing and high tensile stress and containing sacrificial bonds formed by the epoxidized natural rubber has the tearing strength increased by 64 percent at most, the 100 percent tensile stress increased by 182 percent at most and the 300 percent tensile stress increased by 152 percent at most compared with the rubber (without the epoxidized natural rubber) containing the same part of talcum powder.

Compared with the prior art, the rubber containing the sacrificial bond provided by the invention has the advantages of high modulus, high tearing strength, simple and practical preparation method, easy industrialization and capability of being directly combined with the existing production process of rubber products.

Drawings

FIG. 1 is the strain dependence of the storage modulus (G') of IR/ENR mixtures of example 1 with different talc contents;

FIG. 2 is a graph showing the strain dependence of the storage modulus (G') of IR gels of comparative example 1 with different talc contents;

FIG. 3 is a graph showing the strain dependence of the storage modulus (G') of IR/ENR mixtures of example 2 with different talc contents.

Detailed Description

Example 1

The isoprene rubber with high tearing and high stress at definite elongation contains the following raw material components by weight: 90 parts of isoprene rubber IR, 10 parts of epoxidized natural rubber ENR, 5 parts of zinc oxide, 2 parts of stearic acid, 1.2 parts of accelerator (NA22), 2 parts of sulfur and 20 parts, 30 parts and 50 parts of talcum powder (5000 meshes) which are sequentially marked as samples No. 1, No. 2, No. 3 and No. 3 respectively,

Comparative example 1

The isoprene rubber comprises the following raw material components in parts by weight: 100 parts of isoprene rubber, 5 parts of zinc oxide, 2 parts of stearic acid, 1.2 parts of an accelerator (NA22), 2 parts of sulfur, 20 parts of talcum powder, 30 parts of talcum powder and 50 parts of talcum powder, which are sequentially marked as samples No. 4, No. 5 and No. 6 respectively.

The preparation method of the isoprene rubber containing the sacrificial bonds and having high tearing and high stress at definite elongation comprises the following steps:

1) placing the isoprene rubber, the epoxidized natural rubber and the talcum powder in the formula ratio into an oven to be dried for 2 hours, and setting the temperature of the oven to be 55 ℃;

2) setting the front roller temperature of a double-roller open mill at 55 ℃ and the rear roller temperature at 50 ℃, and when the temperature of the open mill reaches the preset temperature, respectively adding the isoprene rubber and the epoxidized natural rubber treated in the step 1) for plastication.

3) Setting the front roller temperature of a double-roller open mill to be 55 ℃, setting the rear roller temperature to be 50 ℃, adding the isoprene rubber and the epoxidized natural rubber processed in the step 2) when the temperature of the open mill reaches the preset temperature, uniformly and continuously wrapping the rubber on the front roller by adopting rolling, reserving a proper amount of stacking rubber above the roller distance, and rolling and turning for 2 minutes to form the smooth gapless roller wrapping rubber.

4) Adding various compounding agents according to the formula amount uniformly along the axial direction of the roller in sequence, after all the compounding agents are added each time, cutting the left and right 3/4 knives twice respectively, wherein the interval between the two cutting knives is 20 seconds; the charging sequence is as follows: stearic acid, zinc oxide, accelerant, talcum powder and sulfur. 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.

5) Will be provided withStanding the rubber compound for 24h, and vulcanizing on a flat vulcanizing machine at the vulcanization temperature of 160 ℃ according to t₉₀And (4) vulcanizing for time.

The dynamic mechanical properties of the compounded rubber sample prepared in step 4) were tested with RPA3000 (high-speed rail). The test conditions for the strain sweep were: temperature: 60 ℃; frequency: 1 Hz; strain: 0 to 280 percent. The strain dependence of the dynamic mechanical properties of filled rubbers is often referred to as Payne effect. This effect is related to the dispersibility of the filler and the interaction of the filler with the rubber matrix. FIG. 1 is a plot of storage modulus (G ') versus strain for the compound of example 1, and FIG. 2 is a plot of storage modulus (G') versus strain for the compound of comparative example 1. After the talcum powder is added into the IR rubber, G' is slightly reduced along with the increase of the using amount of the talcum powder due to the weak agglomeration effect and the weak interface effect with a matrix of the talcum powder. In example 1, the G' is gradually increased with the increase in the amount of talc, which indicates that the force between the talc and the rubber base is gradually increased.

The isothermal vulcanization curve prepared in step 5) was tested using a rubber processing analyzer (RPA3000, high-speed rail). And (3) testing tensile property: according to GB/T528-2009 standard, the test size of the dumbbell-shaped test sample is 2X 4X 20mm³. The test speed was 500 mm/min. The data are shown in table 1 below:

table 1 properties of different samples prepared according to example 1, comparative example 1 and example 2

The data in Table 1 show that the tear strength of the material (1#, 2#, 3 #) in example 1 is much higher than that of the comparative example 1(4#, 5#, 6#, etc.) with the corresponding talcum powder content, wherein the tear strength of the material 2# is 1.54 times that of the material 5 #. The stress at elongation of the material of example 1(1#, 2#, 3 #), is much higher than that of comparative examples 1(4#, 5#, 6#) with corresponding talc content, wherein the stress at elongation of 100% of the material of 3# is 2.12 times that of the material of 6# and the stress at elongation of 300% is 2.52 times that of the material of 6 #.

Example 2

The isoprene rubber with high tearing and high stress at definite elongation contains the following raw material components by weight: 80 parts of isoprene rubber, 20 parts of epoxidized natural rubber, 2 parts of stearic acid, 5 parts of zinc oxide, 1.2 parts of an accelerator (NA22), 2 parts of sulfur and 20 parts, 30 parts and 50 parts of talcum powder (5000 meshes) which are sequentially marked as samples No. 7, No. 8 and No. 9 respectively.

The preparation method of the isoprene rubber with high tearing and high stress at definite elongation containing the sacrificial bonds in the embodiment 2 is the same as that in the embodiment 1.

FIG. 3 is a plot of storage modulus (G ') versus strain for the compound of example 2, and FIG. 2 is a plot of storage modulus (G') versus strain for the compound of comparative example 1. After the talcum powder is added into the IR rubber, G' is slightly reduced along with the increase of the using amount of the talcum powder due to the weak agglomeration effect and the weak interface effect with a matrix of the talcum powder. In example 2, when the amount of talc was 20 parts, G' was the smallest; the G' is gradually increased along with the increase of the dosage of the talcum powder, which shows that the acting force of the talcum powder and the rubber matrix is gradually increased. Example 2 the G' of each compound was greater than the corresponding amount of talc in the compound of example 1.

From the data in table 1, it can be seen that the tear strength of the material of example 2 is much higher than that of comparative example 1 with the corresponding talc content, wherein the tear strength of the material # 9 is 1.60 times that of the material # 6. The stress at elongation of the material of example 2 was much higher than that of comparative example 1 with the corresponding talc content, wherein the stress at 100% elongation of the material # 9 was 2.82 times that of the material # 6, and the stress at 100% elongation was 3.27 times that of the material # 6.