阅读说明：本技术 高阻隔的非填充橡胶组合物及其制备方法 (High-barrier non-filled rubber composition and preparation method thereof ) 是由 张成峰 郭宝春 唐征海 吴思武 张立群 于 2021-10-29 设计创作，主要内容包括：本发明公开了一种高阻隔的非填充橡胶组合物,由50份-200份的高交联橡胶粉末、100份的橡胶生胶、0.8份-2.2份的硫磺A、7份-32份的其它交联助剂制成；高阻隔的非填充橡胶组合物呈海-岛结构；该海-岛结构为由橡胶生胶硫化形成连续的海相结构以及高交联橡胶粉末经过融合取向形成的岛相结构,其长径范围为50nm-50um,长宽比值为1.01-40的岛相结构在所有岛相结构中占比为95％以上。本发明通过引入低渗透系数的高交联橡胶制备高阻隔橡胶材料,提供的制备方法,制备工艺简单,无需对橡胶进行化学改性或添加偶联剂改性填料,不需要任何特殊的加工设备。本发明属于橡胶制备技术领域,适用于提高橡胶的阻隔性能。(The invention discloses a high-barrier non-filled rubber composition which is prepared from 50-200 parts of high-crosslinking rubber powder, 100 parts of raw rubber, 0.8-2.2 parts of sulfur A and 7-32 parts of other crosslinking auxiliaries; the high-barrier non-filled rubber composition is in a sea-island structure; the sea-island structure is a continuous sea phase structure formed by vulcanizing rubber crude rubber and an island phase structure formed by fusing and orienting highly crosslinked rubber powder, wherein the island phase structure with the length-diameter range of 50nm-50um and the length-width ratio of 1.01-40 accounts for more than 95% of all island phase structures. The high-barrier rubber material is prepared by introducing the high-crosslinking rubber with low permeability coefficient, and the preparation method provided by the invention has the advantages of simple preparation process, no need of chemical modification of rubber or addition of coupling agent modified filler, and no need of any special processing equipment. The invention belongs to the technical field of rubber preparation, and is suitable for improving the barrier property of rubber.)

1. The high-barrier non-filled rubber composition is characterized by being prepared from the following raw materials in parts by weight:

50-200 parts of high-crosslinking rubber powder, 100 parts of raw rubber, 0.8-2.2 parts of sulfur A and 7-32 parts of other crosslinking aids;

other crosslinking assistants comprise a promoter A, an activator A and an anti-aging agent A;

the high-crosslinking rubber powder is prepared by crushing high-crosslinking rubber;

the high-barrier non-filled rubber composition is of a sea-island structure; the sea-island structure is a continuous sea phase structure formed by vulcanizing rubber crude rubber and a high cross-linked rubber phase formed by fusing and orienting high cross-linked rubber powder;

the high-crosslinking rubber phase is a dispersed island phase structure, the length-diameter range of the high-crosslinking rubber phase is 50nm-50um, and the island phase structure with the length-width ratio of 1.01-40 accounts for more than 95% of all the island phase structures.

2. The high barrier unfilled rubber composition according to claim 1, wherein the high cross-linked rubber is made from the following raw materials: olefin rubber, an activator B, an anti-aging agent B, an accelerator B and sulfur B;

the olefin rubber is at least one of natural rubber, cis-polyisoprene, trans-polyisoprene, gutta-percha, butadiene rubber, styrene butadiene rubber and nitrile butadiene rubber.

3. The high barrier unfilled rubber composition according to claim 2, wherein the total amount of the olefin rubber to the mixture X, which is a mixture of an activator B, an antioxidant B, an accelerator B and sulfur B, is 100:21 to 100: 52.

4. The high-barrier unfilled rubber composition according to any one of claims 1-3, wherein the highly crosslinked rubber powder has a geometric mean diameter of 10nm to 10um, and D90 of 1 to 30 um;

d90 indicates the value of the diameter on the abscissa corresponding to 90% of the cumulative distribution on the ordinate in a cumulative distribution plot with the ordinate from 0% to 100% of the cumulative particle diameter on the abscissa.

5. The high-barrier unfilled rubber composition according to any one of claims 1-4, wherein the raw rubber is at least one of natural rubber, cis-polyisoprene, trans-polyisoprene, gutta percha, butadiene rubber, styrene butadiene rubber, and nitrile butadiene rubber.

6. A method for preparing the high-barrier unfilled rubber composition according to any one of claims 1 to 5, comprising the steps of: after the high-crosslinking rubber powder, the crude rubber, the sulfur and other crosslinking aids are weighed according to the proportion, blending is completed through an open mill or an internal mixer or a high-speed mixer or a mixing machine, and compression molding is performed to obtain the high-barrier non-filled rubber composition.

7. A process for preparing a high-barrier unfilled rubber composition according to any one of claims 1 to 5, which comprises the following steps in the following order:

s1, weighing other cross-linking auxiliary agents and the rubber crude rubber in proportion, and forming a mixture A in an internal mixer;

s2, weighing the high-crosslinking rubber powder and the sulfur in proportion, putting the mixture in an open mill, blending the mixture with the mixture A, and carrying out compression molding to obtain the high-barrier non-filled rubber composition.

8. A process for preparing a high-barrier unfilled rubber composition according to any one of claims 1 to 5, which comprises the following steps in the following order:

p1, weighing high-crosslinking rubber powder and raw rubber according to a proportion, and premixing a part of the high-crosslinking rubber powder and the raw rubber to obtain a premix A;

p2, mixing the residual high crosslinking rubber powder and the premix A in an open mill to obtain a blend B;

and P3, weighing sulfur and other crosslinking aids in proportion, placing the mixture in an open mill, blending the mixture with the rest raw rubber and the blend B, and carrying out compression molding to obtain the high-barrier non-filled rubber composition.

9. A method of producing a high-barrier unfilled rubber composition according to any one of claims 6 to 8, wherein: and in the compression molding process, the compression molding is carried out according to the positive vulcanization time, and the compression molding pressure is 20-50 MPa.

10. The method for preparing a high-barrier unfilled rubber composition according to any one of claims 6 to 8, wherein: blending of the highly crosslinked rubber powder is carried out using any one of a shearing force, a stretching force, a compression force, ultrasonic energy, electromagnetic energy, thermal energy, or a combination comprising at least two of the foregoing forces or energies.

Technical Field

The invention belongs to the technical field of rubber preparation, relates to rubber with high barrier property, and particularly relates to a high-barrier non-filled rubber composition and a preparation method thereof.

Background

The high-barrier rubber material has the advantages of high elasticity and low permeability coefficient, and has important application in many fields such as aerospace, transportation, biochemical protection and the like. However, due to the loose stacking of rubber molecular chains, a large amount of free volume exists, and the barrier property of unfilled rubber is generally poor, so that the engineering application requirements cannot be met.

The most main method for improving the barrier property of rubber at present is to introduce a high-barrier two-dimensional filler with high specific surface area, but the following defects are difficult to overcome: (1) the kind and source of the high specific surface area two-dimensional filler are limited, and the dependence on the inorganic filler is high; (2) a large amount of filler is generally required to be added, which brings high processing energy consumption and higher product density; (3) rubber material properties are strongly dependent on filler dispersion and filler/rubber interfacial properties, often requiring satisfactory barrier properties to be obtained by optimizing processing conditions and implementing interfacial modifications.

The introduction of special rubber or plastic with low permeability coefficient into the rubber matrix can also modify the gas barrier property of the rubber material. However, considering the problems of high cost and limited sources of high-barrier special rubber, the problems of vulcanization and poor elasticity of rubber-plastic blended materials and the like, the practical application of the methods still has certain difficulty.

Disclosure of Invention

The invention aims to provide a high-barrier non-filled rubber composition, which is prepared by introducing high cross-linked rubber with low permeability coefficient;

it is a further object of the present invention to provide a process for preparing a high barrier unfilled rubber composition.

In order to achieve the purpose, the invention adopts the following technical scheme:

a high-barrier non-filled rubber composition is prepared from the following raw materials in parts by weight:

50-200 parts of high-crosslinking rubber powder, 100 parts of raw rubber, 0.8-2.2 parts of sulfur A and 7-32 parts of other crosslinking aids;

other crosslinking assistants comprise a promoter A, an activator A and an anti-aging agent A;

the high-crosslinking rubber powder is prepared by crushing high-crosslinking rubber;

the high-barrier non-filled rubber composition is of a sea-island structure; the sea-island structure is a continuous sea phase structure formed by vulcanizing rubber crude rubber and a high cross-linked rubber phase formed by fusing and orienting high cross-linked rubber powder;

the high-crosslinking rubber phase is a dispersed island phase structure, the length-diameter range of the high-crosslinking rubber phase is 50nm-50um, and the island phase structure with the length-width ratio of 1.01-40 accounts for more than 95% of all the island phase structures.

By way of limitation, the highly crosslinked rubber is made from the following raw materials: olefin rubber, an activator B, an anti-aging agent B, an accelerator B and sulfur B;

the olefin rubber is at least one of natural rubber, cis-polyisoprene, trans-polyisoprene, gutta-percha, butadiene rubber, styrene butadiene rubber and nitrile butadiene rubber.

By way of further limitation, the total amount ratio of the olefin rubber to the mixture X, which is a mixture of the activator B, the antioxidant B, the accelerator B and the sulfur B, is 100:21 to 100: 52.

As a second limitation, the geometric mean diameter of the highly crosslinked rubber powder is 10nm to 10um, and D90 is 1 to 30 um;

d90 indicates the value of the diameter on the abscissa corresponding to 90% of the cumulative distribution on the ordinate in a cumulative distribution plot with the ordinate from 0% to 100% of the cumulative particle diameter on the abscissa.

As a third limitation, the raw rubber is at least one of natural rubber, cis-polyisoprene, trans-polyisoprene, gutta percha, butadiene rubber, styrene butadiene rubber and nitrile butadiene rubber.

A preparation method of the high-barrier non-filled rubber composition comprises the following steps: after the high-crosslinking rubber powder, the crude rubber, the sulfur and other crosslinking aids are weighed according to the proportion, blending is completed through an open mill or an internal mixer or a high-speed mixer or a mixing machine, and compression molding is performed to obtain the high-barrier non-filled rubber composition.

Another preparation method of the high-barrier non-filled rubber composition comprises the following steps:

s1, weighing other cross-linking auxiliary agents and the rubber crude rubber in proportion, and forming a mixture A in an internal mixer;

s2, weighing the high-crosslinking rubber powder and the sulfur in proportion, putting the mixture in an open mill, blending the mixture with the mixture A, and carrying out compression molding to obtain the high-barrier non-filled rubber composition.

A further process for preparing the above high-barrier, non-filled rubber composition is carried out in the following order of steps:

p1, weighing high-crosslinking rubber powder and raw rubber according to a proportion, and premixing a part of the high-crosslinking rubber powder and the raw rubber to obtain a premix A;

p2, mixing the residual high crosslinking rubber powder and the premix A in an open mill to obtain a blend B;

and P3, weighing sulfur and other crosslinking aids in proportion, placing the mixture in an open mill, blending the mixture with the rest raw rubber and the blend B, and carrying out compression molding to obtain the high-barrier non-filled rubber composition.

As a limitation: and in the compression molding process, the compression molding is carried out according to the positive vulcanization time, and the compression molding pressure is 20-50 MPa.

As a second limitation: blending of the highly crosslinked rubber powder is carried out using any one of a shearing force, a stretching force, a compression force, ultrasonic energy, electromagnetic energy, thermal energy, or a combination comprising at least two of the foregoing forces or energies.

Due to the adoption of the technical scheme, compared with the prior art, the invention has the technical progress that:

(1) according to the invention, the cross-linking density of the cross-linked rubber is improved, so that the spacing of rubber molecular chains can be reduced, the chain segment movement is restrained, and the free volume content is reduced, so that the gas permeability coefficient of the rubber is reduced;

(2) the preparation method provided by the invention has simple preparation process, does not need to carry out chemical modification on rubber or add coupling agent to modify the filler, and does not need any special processing equipment;

(3) the invention can realize the regulation and control of the barrier property of the rubber material by changing the dosage and the morphological structure of the high crosslinking density crosslinked rubber, the crosslinking density (the dosage of sulfur and accelerant) of the high crosslinking density crosslinked rubber and the crosslinking density (the dosage of sulfur and accelerant) of the rubber matrix;

(4) according to the invention, by preparing the multiphase rubber composition with the sea-island structure, the sea-island structure can well inhibit the micro-crack expansion of the high-crosslinking rubber, and the barrier property of the rubber composition is obviously improved under the condition of keeping good elongation;

(5) in the invention, the molding pressure of the vulcanization treatment is related to the length-diameter ratio of the island phase, and the high molding pressure is favorable for having a larger length-diameter ratio to form a remarkable tortuous effect, thereby improving the barrier property of the material.

The invention belongs to the technical field of rubber preparation, and is suitable for improving the barrier property of rubber.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention and not to limit the invention.

In the drawings:

fig. 1 is a schematic diagram of an island phase structure in embodiment 1 of the present invention.

Detailed Description

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for purposes of illustration and explanation only and are not intended to limit the present invention.

Example 1 preparation of a high Barrier, unfilled rubber composition

The process for preparing the high barrier unfilled rubber composition of this example was carried out in the following order of steps:

preparation of mono-and highly crosslinked rubber powder

100kg of natural rubber, 5kg of zinc oxide, 2kg of stearic acid, 1kg of age inhibitor 6PPD, 4kg of accelerator CZ and 12kg of sulfur are added into an open mill and stirred at 25 DEG^oC, mixing for 10 min; molding the obtained rubber compound by a flat vulcanizing machine at 143 ℃ for positive vulcanization time, wherein the molding pressure is 15MPa, and obtaining the high-crosslinking rubber a;

crushing the high-crosslinking rubber a on an open mill to obtain high-crosslinking rubber powder with the geometric mean size of 100nm-10um, wherein D90 is 1-30 um; d90 is the diameter value of the abscissa corresponding to 90% of the cumulative distribution of the ordinate in the cumulative distribution graph with the ordinate of 0% -100% and the abscissa of the particle diameter;

preparation of two-component high-barrier non-filled rubber composition

Adding the obtained high-crosslinking rubber powder, natural rubber, zinc oxide, stearic acid, age inhibitor 6PPD, accelerator CZ and sulfur into an internal mixer according to the formulas of sample 1, sample 2 and sample 3 in the table 1 respectively, and internally mixing for 10min at 60 ℃; the resulting rubber compound was molded at 143 ℃ for a positive cure time with a press vulcanizer at a mold pressure of 25MPa to obtain high barrier unfilled rubber compositions corresponding to sample 1, sample 2 and sample 3, respectively.

The obtained high-barrier non-filled rubber composition has a sea-island structure in a transmission electron microscope picture; the sea-island structure is a continuous sea phase structure formed by vulcanizing rubber crude rubber and a high cross-linked rubber phase formed by fusing and orienting high cross-linked rubber powder.

The high cross-linked rubber phase is in a dispersed island phase structure, the length diameter range of the high cross-linked rubber phase is 50nm-50um, the high cross-linked rubber phase has a certain length-width ratio, and the island phase structure with the length-width ratio of 1.01-40 accounts for more than 95% of all the island phase structures, as shown in figure 1.

The method for testing the length-width ratio of the island phase structure comprises the steps of introducing a shot transmission electron microscope image into Photoshop or Nano measurer image processing software, and testing the software by comparing a scale in the transmission electron microscope image to obtain the specific major axis of the island phase structure and the specific width in the direction perpendicular to the major axis; and dividing the measured length diameter of the island phase structure by the width diameter perpendicular to the length diameter direction to obtain the length-width ratio of the island phase structure.

The island phase structure proportion test method with the length-width ratio of 1.01-40 refers to that a plurality of transmission electron microscope images in different regions are obtained by random shooting, the length-width ratio of each island phase structure in the transmission electron microscope images is obtained by measuring the length-width ratio of the island phase structure one by the method for measuring the length-width ratio of the island phase structure, the length-width ratio of 500 specific island phase structures is obtained by random measurement, and the island phase structure proportion with the length-diameter ratio of 1.01-40 is divided by 500 to obtain the island phase structure proportion with the fixed length-width ratio range.

The internal mixer in the second step can be replaced by an open mill, a high-speed mixer or a mixer.

Preparation of comparative sample 1: adding natural rubber, zinc oxide, stearic acid, antioxidant 6PPD, accelerator CZ and sulfur into an internal mixer according to the formula of a reference sample 1 in Table 1, and internally mixing for 10min at 60 ℃; the resulting rubber compound was molded at 143 ℃ for a positive vulcanization time with a press vulcanizer at a mold pressure of 15MPa to obtain a normally crosslinked natural rubber, comparative example 1.

Preparation of comparative sample 2: adding natural rubber, zinc oxide, stearic acid, antioxidant 6PPD, accelerator CZ and sulfur into an internal mixer according to the formula of a comparison sample 2 in Table 1, and internally mixing for 10min at 60 ℃; the resulting rubber compound was compression molded at 143 ℃ for a positive vulcanization time using a press vulcanizer to obtain homogeneous highly crosslinked natural rubber, the compression molding pressure was 15MPa, i.e., control 2.

Preparation of comparative sample 3: adding natural rubber, organic clay, zinc oxide, stearic acid, age inhibitor 6PPD, accelerator CZ and sulfur into an internal mixer according to the formula of a comparison sample 3 in Table 1, and internally mixing for 10min at 60 ℃; the resulting rubber compound was molded at 143 ℃ for a positive vulcanization time by a press vulcanizer at a molding pressure of 15MPa to obtain a natural rubber filled with 10 parts of an organoclay, comparative example 3.

Preparation of comparative sample 4: adding uncrushed high-crosslinked rubber a, natural rubber, zinc oxide, stearic acid, age inhibitor 6PPD, accelerator CZ and sulfur into an internal mixer according to the formula of a comparison sample 4 in Table 1, and internally mixing for 10min at 60 ℃; the resulting rubber composition was molded at 143 ℃ for a positive vulcanization time with a press vulcanizer at a molding pressure of 25MPa to obtain a natural rubber containing uncrushed crosslinked rubber A of high crosslinking density, namely comparative example 4.

Preparation of comparative sample 5: adding the obtained high-crosslinking rubber powder, natural rubber, zinc oxide, stearic acid, age inhibitor 6PPD, promoter CZ and sulfur into an internal mixer according to the formula of the comparison sample 5 in the table 1, and internally mixing for 10min at 60 ℃; the resulting rubber compound was molded at 143 ℃ for a positive vulcanization time by means of a press vulcanizer at a molding pressure of 15MPa to obtain a rubber composition which was not subjected to high-pressure molding, namely comparative example 5.

TABLE 1

The units for each material in table 1 are in kilograms. The performance test conditions of the samples in table 1 are shown in table 2.

TABLE 2

As can be seen from Table 2, the nitrogen gas permeation of the rubber continued to decrease with increasing powder of the highly crosslinked rubber as compared with the normally crosslinked natural rubber (comparative example 1). The gas permeation coefficient of the high barrier unfilled rubber composition (sample 3) with similar crosslink density decreased more than that of the homogeneous highly crosslinked natural rubber (comparative 2), and the heterogeneous structure of sample 3 maintained good elongation. When 100 parts of the highly crosslinked rubber powder was added, the barrier properties were similar to those of 10 parts of the organoclay-filled natural rubber (comparative sample 3), and the barrier properties of the highly crosslinked rubber powder-containing natural rubber were comparable to those of the rubber composite. The natural rubber containing high-barrier rubber powder (sample 2) having the same content of the high-crosslinked rubber powder had a lower nitrogen gas permeability coefficient than the natural rubber containing non-pulverized high-crosslinked rubber a (comparative sample 4). The nitrogen gas permeability coefficient of the high-pressure-molded natural rubber containing the high-barrier rubber powder (sample 2) was lower than that of the natural rubber containing the high-barrier rubber a powder (comparative sample 5) which was not high-pressure-molded.

From the above analysis, it can be seen that, by the island phase structure of the highly crosslinked rubber in the rubber composition formulation, the barrier property of the rubber composition can be significantly improved without affecting the ductility thereof when the ratio of the length to the width of the island phase structure is 1.01 to 40 at 90% or more and 90% or more.

Example 2 preparation of a high-Barrier, non-filled rubber composition

The process for preparing the high barrier unfilled rubber composition of this example was carried out in the following order of steps:

preparation of mono-and highly crosslinked rubber powder

Styrene butadiene rubber, zinc oxide, stearic acid, age inhibitor 6PPD, accelerant CZ and sulfur are respectively added into an internal mixer according to the formula of the high cross-linked rubber B1, B2 and B3 in the table 3, internal mixing is carried out for 15min at 80 ℃, the obtained mixed rubber is molded by a flat vulcanizing machine at 150 ℃ according to the normal vulcanization time, the molding pressure is 15MPa, and the high cross-linked rubber B1, the high cross-linked rubber B2 and the high cross-linked rubber B3 are obtained;

respectively crushing the high cross-linked rubber B1, the high cross-linked rubber B2 and the high cross-linked rubber B3 in a freezing ball mill, wherein the vibration speed is 1600r/mim, the crushing time is 4min, and high cross-linked rubber B1 powder, high cross-linked rubber B2 powder and high cross-linked rubber B3 powder are obtained, the geometric mean size range of the powder is 10nm-2um, and D90 is 1-30 um;

preparation of two-component high-barrier non-filled rubber composition

Adding the high-crosslinking rubber B1 powder/high-crosslinking rubber B2 powder/high-crosslinking rubber B3 powder, styrene-butadiene rubber, zinc oxide, stearic acid, antioxidant 6PPD, accelerator CZ and sulfur into an open mill according to the formulas of sample 4, sample 5 and sample 6 in Table 4 respectively, and adding the mixture into the open mill at 25 DEG^oOpen milling for 10min under C; the resulting rubber compound was compression molded at 150 ℃ for a positive cure time with a compression molding pressure of 25MPa using a press vulcanizer to obtain high barrier unfilled rubber compositions corresponding to sample 4, sample 5 and sample 6, respectively.

The obtained high-barrier non-filled rubber composition has a sea-island structure in a transmission electron microscope picture; the sea-island structure is a continuous sea phase structure formed by vulcanizing rubber crude rubber and a high cross-linked rubber phase formed by fusing and orienting high cross-linked rubber powder.

The high cross-linked rubber phase is in a dispersed island phase structure, the length-diameter range of the high cross-linked rubber phase is 50nm-50um, the high cross-linked rubber phase has a certain length-width ratio, and the island phase structure with the length-width ratio of 1.01-40 accounts for more than 95% of all the island phase structures.

Preparation of sample 7: adding styrene butadiene rubber, zinc oxide, stearic acid, antioxidant 6PPD, accelerator CZ and sulfur into an internal mixer according to the formula of a sample 7 in the table 4, and internally mixing for 10min at 80 ℃ to form rubber compound; weighing high-crosslinking rubber powder B1 and sulfur according to the formula of sample 7 in Table 4, adding the high-crosslinking rubber powder B1 and sulfur and the rubber compound into an open mill, and milling for 10min at 80 ℃; the resulting rubber compound was compression molded at 150 ℃ for a positive cure time using a press vulcanizer at a compression molding pressure of 25MPa to give a high barrier unfilled rubber composition, sample 7.

Preparation of sample 8: push-watch4, weighing the high-crosslinking rubber powder B1 and the styrene-butadiene rubber according to the formula of the sample 8, adding half of the high-crosslinking rubber powder B1 and the styrene-butadiene rubber into an internal mixer, and internally mixing for 5min at 80 ℃ to form rubber compound; the resulting rubber mix was charged to an open mill with the remaining highly crosslinked rubber powder B1 at 25^oOpen milling for 5min under C; adding the obtained rubber compound, residual styrene butadiene rubber, zinc oxide, stearic acid, an anti-aging agent 6PPD, an accelerator CZ and sulfur into an open mill according to the formula of a sample 8 in the table 4, and milling for 10min at 25 ℃; the resulting rubber compound was compression molded at 150 ℃ for a positive cure time using a press vulcanizer at a compression molding pressure of 25MPa to give a high barrier unfilled rubber composition, sample 8.

Preparation of comparative sample 6: styrene butadiene rubber, zinc oxide, stearic acid, age inhibitor 6PPD, accelerator CZ and sulfur were added to the open mill according to the formula of comparative sample 5 in Table 4, 25^oC, open milling for 10 min; the resulting rubber compound was compression molded at 150 ℃ for a positive vulcanization time with a compression molding pressure of 15MPa using a press vulcanizer to obtain a normally crosslinked styrene-butadiene rubber, comparative sample 5.

Preparation of comparative example 7: styrene butadiene rubber, zinc oxide, stearic acid, age inhibitor 6PPD, accelerator CZ and sulphur were added to the mill according to the formula of comparative sample 6 in Table 4, 25^oC, open milling for 10 min; the obtained rubber compound was molded at 150 ℃ for a positive vulcanization time with a press vulcanizer at a molding pressure of 15MPa to obtain homogeneous highly crosslinked styrene-butadiene rubber, i.e., comparative sample 6.

Preparation of comparative sample 8: styrene butadiene rubber, organic clay, zinc oxide, stearic acid, age inhibitor 6PPD, accelerator CZ and sulfur were added to the mill according to the formula of comparative sample 8 in Table 4, 25^oC, open milling for 10 min; the resulting rubber compound was compression molded at 150 ℃ for a positive vulcanization time with a compression molding pressure of 15MPa using a press vulcanizer to obtain a normally crosslinked styrene-butadiene rubber, comparative sample 8.

TABLE 3

The units for each material in table 3 are in kilograms.

TABLE 4

The units for each material in table 4 are in kilograms. The performance test conditions of the samples in this example are shown in Table 5.

TABLE 5

As can be seen from Table 5, the gas permeation of the rubber continued to decrease as the amount of sulfur and accelerators in the high barrier unfilled rubber composition increased as compared to the conventional crosslinked styrene-butadiene rubber (control 6). High barrier unfilled rubber compositions prepared by different mixing processes maintained similar barrier properties under the same formulation (samples 4,7 and 8). Compared with homogeneous highly crosslinked styrene-butadiene rubber (comparative sample 7) of similar crosslinking density, sample 6 to which highly crosslinked rubber B3 powder was added had a significantly reduced nitrogen permeation coefficient and maintained good elongation; the barrier properties of sample 6 with the addition of the highly crosslinked rubber B3 powder were significantly better than 10 parts of organoclay-filled styrene-butadiene rubber (control 8).

The same test results were obtained when the natural rubber and styrene-butadiene rubber in examples 1 and 2 were replaced with either cis-polyisoprene, trans-polyisoprene, gutta percha, cis-butadiene rubber or nitrile rubber, or with a mixture of two or more of natural rubber, cis-polyisoprene, trans-polyisoprene, gutta percha, cis-butadiene rubber, styrene-butadiene rubber and nitrile rubber.

In conclusion, the addition of the high-barrier powder prepared from the high-crosslinking-density crosslinked rubber to the sulfur-vulcanized olefin rubber can significantly improve the barrier property of the rubber composition, is significantly superior to that of homogeneous high-crosslinking rubber materials, and reaches or even is superior to that of the traditional organic clay filled rubber materials. Therefore, the addition of the highly crosslinked rubber in the present invention can give an unfilled rubber composition having high barrier properties.

Blending of the highly crosslinked rubber powder with other materials in examples 1 and 2 is carried out using any one of shear force, extensional force, compressive force, ultrasonic energy, electromagnetic energy, thermal energy, or a combination comprising at least two of the foregoing forces or energies. Blending involving the aforementioned forces may be performed in a machine such as a single or multiple screw extruder, Buss kneader, henschel mixer, screw mixer, Ross mixer, internal mixer, roll mill, molding machine, or a combination comprising at least two of the foregoing machines. Wherein the molding machine may be an injection molding machine, a vacuum molding machine, or a blow molding machine.

The process of pulverizing the highly crosslinked rubber in examples 1 and 2 can be carried out in any one of an internal mixer, a high-speed ball mill, or an automatic mill.

Example 3 preparation of a high Barrier, unfilled rubber composition

The process for preparing the high barrier unfilled rubber composition of this example was carried out in the following order of steps:

preparation of mono-and highly crosslinked rubber powder

100kg of natural rubber, 5kg of zinc oxide, 2kg of stearic acid, 1kg of age inhibitor 6PPD, 4kg of accelerator CZ and 12kg of sulfur are added into an open mill and stirred at 25 DEG^oC, mixing for 10 min; molding the obtained rubber compound by a flat vulcanizing machine at 143 ℃ for positive vulcanization time, wherein the molding pressure is 15MPa, and obtaining high cross-linked rubber c;

crushing the high cross-linked rubber C in an automatic grinding instrument at a vibration speed of 1600r/mim for 4min to obtain high cross-linked rubber C1 powder, wherein the geometric average size range of the powder is 60nm-1um, and D90 is 1-10 um;

preparation of two-component high-barrier non-filled rubber composition

S1, weighing 100kg of styrene butadiene rubber, 1kg of zinc oxide, 2kg of stearic acid, 2kg of antioxidant 6PPD and 2kg of accelerator CZ, and forming a mixture M1 in an internal mixer;

s2, weighing 100kg of high-crosslinking rubber powder c and 0.8kg of sulfur, putting the high-crosslinking rubber powder c and the sulfur into an open mill, blending the mixture with the mixture M1, and carrying out compression molding under the mold pressing pressure of 20MPa to obtain the high-barrier non-filled rubber composition.

The high-barrier unfilled rubber compositions prepared in this example were tested to have the same properties as the high-barrier unfilled rubber compositions prepared in examples 1 and 2.

Example 4 preparation of a high Barrier, unfilled rubber composition

The process for preparing the high barrier unfilled rubber composition of this example was carried out in the following order of steps:

preparation of mono-and highly crosslinked rubber powder

100kg of butadiene rubber, 5kg of zinc oxide, 2kg of stearic acid, 6kg of antioxidant 6PPD, 4kg of accelerator CZ and 12kg of sulfur are added into an open mill at 25 DEG^oC, mixing for 10 min; molding the obtained rubber compound at 143 ℃ for positive vulcanization time by using a flat vulcanizing machine, wherein the molding pressure is 15MPa, and obtaining high cross-linked rubber d;

crushing the high-crosslinked rubber D in an automatic grinding instrument at a vibration speed of 1600r/mim for 4min to obtain high-crosslinked rubber D1 powder, wherein the geometric mean size range of the powder is 80nm-5um, and the D90 is 1-20 um;

preparation of two-component high-barrier non-filled rubber composition

P1, weighing 200kg of high-crosslinking rubber powder d and 100kg of butadiene rubber;

premixing 70kg of high-crosslinking rubber powder d with 60kg of butadiene rubber to obtain a premix M2;

p2, mixing the residual 130kg of high crosslinking rubber powder d with the premix M2 in an open mill to obtain a blend M3;

p3, weighing 2.2kg of sulfur, 8kg of zinc oxide, 5kg of stearic acid, 6kg of anti-aging agent 4010NA, 9kg of accelerator CZ and 4kg of accelerator DM, placing the materials in an open mill, blending the materials with the rest 40kg of butadiene rubber and the blend M3, and carrying out compression molding at the die pressing pressure of 50MPa to obtain the high-barrier non-filled rubber composition.

The high-barrier unfilled rubber compositions prepared in this example were tested to have the same properties as the high-barrier unfilled rubber compositions prepared in examples 1 and 2.