阅读说明：本技术 一种定位节点橡胶组合物及其制备方法 (Positioning node rubber composition and preparation method thereof ) 是由 隋世昆 王化景 赵帅 丁天梁 刘云浩 潘志业 于 2020-12-31 设计创作，主要内容包括：本发明提供一种定位节点橡胶组合物,按重量份数计包括：氯丁橡胶40-60份；异戊橡胶20-30份；环氧天然胶10-30份；阿拉伯胶3-5份；硬脂酸1.5-3份；聚乙二醇0.5-2份；防老剂3-9份；微晶蜡1-3份；炭黑N3305-10份；纳米级二氧化硅5-15份；不饱和羧酸5-10份；氧化锌5-15份；氧化镁1-3份；硫磺0.3-1份；促进剂0.5-1.7份；DCP1-2份；氧化钙3-5份,旨在提供一种能同时满足50pphm×40℃×0～20％E动态臭氧试验龟裂发生32h以上和低温脆化温度-50℃以下这两个技术要求的绝缘橡胶组合物,本发明的另一目的是提供一种定位节点橡胶组合物的制备方法。(The invention provides a positioning node rubber composition which comprises the following components in parts by weight: 40-60 parts of chloroprene rubber; 20-30 parts of isoprene rubber; 10-30 parts of epoxy natural rubber; 3-5 parts of Arabic gum; 1.5-3 parts of stearic acid; 0.5-2 parts of polyethylene glycol; 3-9 parts of an anti-aging agent; 1-3 parts of microcrystalline wax; 5-10 parts of carbon black N330; 5-15 parts of nano-scale silicon dioxide; 5-10 parts of unsaturated carboxylic acid; 5-15 parts of zinc oxide; 1-3 parts of magnesium oxide; 0.3-1 part of sulfur; 0.5-1.7 parts of an accelerator; 1-2 parts of DCP; 3-5 parts of calcium oxide, aiming at providing an insulating rubber composition which can simultaneously meet the two technical requirements of crack generation for more than 32 hours in a 50pphm multiplied by 40 ℃ X0-20% E dynamic ozone test and a low-temperature embrittlement temperature below-50 ℃, and the invention also aims at providing a preparation method of the positioning node rubber composition.)

1. A positioning node rubber composition is characterized by comprising the following components in parts by weight: 40-60 parts of chloroprene rubber; 20-30 parts of isoprene rubber; 10-30 parts of epoxy natural rubber; 3-5 parts of Arabic gum; 1.5-3 parts of stearic acid; 0.5-2 parts of polyethylene glycol; 3-9 parts of an anti-aging agent; 1-3 parts of microcrystalline wax; 5-10 parts of carbon black N330; 5-15 parts of nano-scale silicon dioxide; 5-10 parts of unsaturated carboxylic acid; 5-15 parts of zinc oxide; 1-3 parts of magnesium oxide; 0.3-1 part of sulfur; 0.5-1.7 parts of an accelerator; 1-2 parts of DCP; 3-5 parts of calcium oxide.

2. The rubber composition for positioning nodes as claimed in claim 1, wherein the anti-aging agent is a mixture of anti-aging agent 4010NA, anti-aging agent 4020 and anti-aging agent RD, and the weight ratio of the anti-aging agent to the anti-aging agent is 1: 1: 1 are mixed.

3. The positioning node rubber composition of claim 1, wherein the accelerator comprises the following components in parts by weight: accelerant NA-220.1-0.3 parts; 0.1-0.4 part of accelerator DM; 0.2-0.6 part of accelerator CZ; 0.1-0.4 part of accelerator TT.

4. A method for preparing the positioning node rubber composition according to claim 1, comprising the steps of:

(1) weighing: weighing the raw materials according to the proportion in the formula;

(2) pretreatment of raw materials: uniformly mixing the carbon black N330, the nano-scale silicon dioxide and the unsaturated carboxylic acid weighed in the step (1), activating for twenty minutes by microwave, and cooling for later use;

(3) primary pressurizing and mixing: adding chloroprene rubber, isoprene rubber, epoxy natural rubber, Arabic gum, the carbon black N330 treated in the step (1), nano-silicon dioxide, unsaturated carboxylic acid and half of zinc oxide into an internal mixer for mixing, wherein the upper plug pressure is 0.5-0.6MPa, and the mixing time is 3-5 minutes;

(4) secondary pressurizing and mixing: adding stearic acid, polyethylene glycol, an anti-aging agent, microcrystalline wax and calcium oxide into an internal mixer for mixing, wherein the upper plug pressure is 0.5-0.6MPa, and the mixing time is 1-3 minutes;

(5) thirdly, pressurizing and mixing, namely adding the magnesium oxide, the residual zinc oxide, the sulfur, the accelerant and the DCP into an internal mixer for mixing, wherein the top plug pressure is 0.5-0.6MPa, and the mixing time is 1-3 minutes;

(6) and (3) sheet discharging: and (5) discharging the rubber processed in the step (5) to an open mill, and adjusting the roll spacing to 2mm and lower the sheet.

Technical Field

The invention belongs to the technical field of rubber, and particularly relates to a positioning node rubber composition and a preparation method thereof.

Background

A series of positioning nodes can restrict the mutual positions of the wheel set and the framework, so that the position of the axle box on the bogie and the movement range are limited within a certain range, the load is transmitted and distributed to the wheel set, the wheel set can rotate flexibly, and the bogie can smoothly pass through a curve. A series of positioning nodes are composed of a mandrel and elastic rubber and serve as a motor train type A component, once the rubber performance cannot meet the requirement, problems occur in the running process of a train, the train can be unstable and even derailed, and therefore the rubber formula of the positioning nodes is of great importance.

According to the technical requirements of hardness and tensile strength of products and the application of the rubber as a damping part in practical use, the rubber conventionally used is natural rubber and chloroprene rubber. The natural rubber has good low-temperature resistance but poor ozone resistance, and even if a large amount of anti-aging agent is added, the rubber is cracked in 32 hours in a dynamic ozone test of 50pphm multiplied by 40 ℃ multiplied by 0-20% E; chloroprene rubber has good ozone resistance but poor low-temperature resistance, and even if a large amount of plasticizer is added, the lowest low-temperature embrittlement temperature is-45 ℃; ethylene propylene rubber is used as the natural rubber, and the ethylene propylene rubber does not crack after being tested for 32 hours by 50pphm multiplied by 40 ℃ multiplied by 0-20% E dynamic ozone, but the tensile strength is less than 19.6 MPa; the natural rubber is used together with butadiene rubber or the natural rubber is used together with a small amount of chloroprene rubber, and the rubber is cracked within 32 hours in a dynamic ozone test of 50pphm multiplied by 40 ℃ multiplied by 0-20% E.

The prior art therefore remains to be improved.

Disclosure of Invention

The invention aims to provide a positioning node rubber composition, and aims to provide an insulating rubber composition which can simultaneously meet the two technical requirements of cracking occurrence for more than 32 hours in a 50pphm x 40 ℃ x 0-20% E dynamic ozone test and a low-temperature embrittlement temperature of-50 ℃.

In order to solve the problems, the technical scheme adopted by the invention is as follows:

a positioning node rubber composition comprises the following components in parts by weight: 40-60 parts of chloroprene rubber; 20-30 parts of isoprene rubber; 10-30 parts of epoxy natural rubber; 3-5 parts of Arabic gum; 1.5-3 parts of stearic acid; 0.5-2 parts of polyethylene glycol; 3-9 parts of an anti-aging agent; 1-3 parts of microcrystalline wax; 5-10 parts of carbon black N330; 5-15 parts of nano-scale silicon dioxide; 5-10 parts of unsaturated carboxylic acid; 5-15 parts of zinc oxide; 1-3 parts of magnesium oxide; 0.3-1 part of sulfur; 0.5-1.7 parts of an accelerator; 1-2 parts of DCP; 3-5 parts of calcium oxide;

specifically, considering that a series of positioning node products have the requirements of ozone resistance and fatigue resistance tests, the heat generation and the permanent deformation of isoprene rubber are lower than those of natural rubber, and the fatigue resistance is better; the epoxy natural rubber has low double bond content and good ozone resistance, so the chloroprene rubber and the isoprene rubber are selected and used together.

The anti-aging agent is a mixture of anti-aging agent 4010NA, anti-aging agent 4020 and anti-aging agent RD, and the weight ratio of the anti-aging agent to the anti-aging agent is 1: 1: 1, mixing;

the accelerant consists of the following components in parts by weight: accelerant NA-220.1-0.3 parts; 0.1-0.4 part of accelerator DM; 0.2-0.6 part of accelerator CZ; 0.1-0.4 part of accelerator TT;

the invention also provides a preparation method of the positioning node rubber composition, which comprises the following steps:

(1) weighing: weighing the raw materials according to the proportion in the formula;

(2) pretreatment of raw materials: uniformly mixing the carbon black N330, the nano-scale silicon dioxide and the unsaturated carboxylic acid weighed in the step (1), activating for twenty minutes by microwave, and cooling for later use;

(3) primary pressurizing and mixing: adding chloroprene rubber, isoprene rubber, epoxy natural rubber, Arabic gum, the carbon black N330 treated in the step (1), nano-silicon dioxide, unsaturated carboxylic acid and half of zinc oxide into an internal mixer for mixing, wherein the upper plug pressure is 0.5-0.6MPa, and the mixing time is 3-5 minutes;

(4) secondary pressurizing and mixing: adding stearic acid, polyethylene glycol, an anti-aging agent, microcrystalline wax and calcium oxide into an internal mixer for mixing, wherein the upper plug pressure is 0.5-0.6MPa, and the mixing time is 1-3 minutes;

(5) thirdly, pressurizing and mixing, namely adding the magnesium oxide, the residual zinc oxide, the sulfur, the accelerant and the DCP into an internal mixer for mixing, wherein the top plug pressure is 0.5-0.6MPa, and the mixing time is 1-3 minutes;

(6) and (3) sheet discharging: and (5) discharging the rubber processed in the step (5) to an open mill, and adjusting the roll spacing to 2mm and lower the sheet.

The invention has the beneficial effects that:

1. the rubber refined by the invention can meet all rubber technical requirements of a series of positioning nodes, the hardness (Share A) is 45 +/-3 HA, the tensile strength is more than 19.6MPa, the elongation at break is more than 450%, the compression permanent deformation is less than 20% at 70 ℃ multiplied by 24 multiplied by 25%, the static ozone test crack at 50pphm multiplied by 40 ℃ multiplied by 20% E is more than 200h, the dynamic ozone test crack at 50pphm multiplied by 40 ℃ multiplied by 0-20% E is more than 32h, the applied voltage is more than 500V, the electric insulation resistance is more than 1.0 multiplied by 108 omega, the low-temperature embrittlement temperature is less than 50 ℃, the thermal aging hardness change point is less than 7 at 70 ℃ multiplied by 96h, the tensile strength is less than 15%, the elongation at break is less than 20%, the product fatigue test can reach more than 600 ten thousand times, compared with other similar products, the rubber HAs better elasticity, good vibration damping effect, smaller dynamic stiffness/static stiffness, small intramolecular friction and small internal loss, the heat generation is low, the fatigue test effect is better, and the service life of the product is longer.

2. According to the invention, unsaturated carboxylic acid, zinc oxide and magnesium oxide are added, a neutralization reaction is carried out in the mixing and shearing process to generate MSUCA monomer particles in situ, MSUCA is grafted to a rubber molecular chain by DCP in the vulcanization process to form a nano ion cluster and ion cross-linked bond structure, when the rubber molecular chain is acted by external stress, the ion cross-linked bond can generate recombination and mechanical relaxation phenomena similar to a polysulfide cross-linked bond, the action not only can effectively relax the external stress, but also can enable the rubber molecular chains to be more orderly arranged through relative sliding, so that the stress is commonly borne, the generation of stress concentration is avoided, the heat generation in the product fatigue process is reduced, and the fatigue resistance of the product is improved.

3. The nano-scale silicon dioxide is added, so that the reinforcing effect is better, the conductivity of the carbon black in the rubber material is reduced, and meanwhile, cations are generated by friction in the mixing process, so that the insulating property of the rubber material is improved, and the insulating requirement of a product is met.

4. Compared with the traditional small material-large material-vulcanizing agent processing technology, the large material-small material-vulcanizing agent processing technology enables MSUCA generated by in-situ reaction to have higher initial dispersion degree and smaller initial particle size in rubber compound, and can obtain higher in-situ polymerization conversion rate, so that rubber has higher ionic bond crosslinking density and mechanical property; compared with the traditional method of adding the sulfur accelerator to the open mill, the method of the invention adds the sulfur accelerator to the internal mixer, thereby avoiding the reduction of the mechanical property of the rubber caused by repeated remixing.

5. The calcium oxide is added and serves as an alkaline substance, so that the calcium oxide can neutralize redundant acid, provide an alkaline environment for rubber materials, promote vulcanization of rubber, improve mechanical properties of the rubber, and serve as a defoaming agent to improve density of the rubber.

6. The gum arabic is added, is a natural gum and is environment-friendly, safe and harmless; the rubber is heated to be softened at normal temperature, so that heat generated by rubber deformation can be absorbed in the product fatigue test process, and meanwhile, the rubber plays a role of a plasticizer after being heated and softened, so that heat generation is reduced, and the fatigue resistance of the product is improved.

7. Before mixing, the carbon black N330, the nano-scale silicon dioxide and the unsaturated carboxylic acid are subjected to microwave activation treatment, and the unsaturated carboxylic acid can be fully and uniformly mixed with the carbon black N330 and the nano-scale silicon dioxide during activation, so that corrosion to mixing equipment is avoided; the dispersibility of the unsaturated carboxylic acid is improved, the in-situ polymerization reaction efficiency is further improved, and the ionic crosslinking density is improved, so that the fatigue resistance of the rubber is improved; the microwave activation increases the surface active groups of the nano-scale silicon dioxide, and improves the dispersibility and the reinforcing effect of the nano-scale silicon dioxide in the rubber material.

Detailed Description

In order to clearly illustrate the technical features of the present solution, the present solution is explained below by way of specific embodiments.

Example one

The positioning node rubber composition comprises the following components in parts by weight:

40 parts of chloroprene rubber; 30 parts of isoprene rubber; 30 parts of epoxy natural rubber; 2 parts of stearic acid; 1 part of polyethylene glycol; 2 parts of anti-aging agent 4010 NA; 40202 parts of an anti-aging agent; 2 parts of an anti-aging agent RD; 3 parts of microcrystalline wax; 5 parts of calcium oxide; 5 parts of Arabic gum; carbon black N33010 parts; 5 parts of nano-scale silicon dioxide; 10 parts of unsaturated carboxylic acid; 3 parts of magnesium oxide; 15 parts of zinc oxide; 1 part of sulfur; accelerant NA-220.1 parts; 0.4 part of accelerator DM; 0.6 part of accelerator CZ; 0.4 part of accelerator TT; 1 parts of DCP;

the preparation method comprises the following steps:

(3) weighing: weighing the raw materials according to the proportion in the formula;

(4) pretreatment of raw materials: uniformly mixing the carbon black N330, the nano-scale silicon dioxide and the unsaturated carboxylic acid weighed in the step (1), activating for twenty minutes by microwave, and cooling for later use;

(3) primary pressurizing and mixing: adding chloroprene rubber, isoprene rubber, epoxy natural rubber, Arabic gum, the carbon black N330 treated in the step (1), nano-silicon dioxide, unsaturated carboxylic acid and 7.5 parts of zinc oxide into an internal mixer for mixing, wherein the top plug pressure is 0.5-0.6MPa, and the mixing time is 5 minutes;

(4) secondary pressurizing and mixing: adding stearic acid, polyethylene glycol, an anti-aging agent, microcrystalline wax and calcium oxide into an internal mixer for mixing, wherein the upper plug pressure is 0.5-0.6MPa, and the mixing time is 3 minutes;

(5) thirdly, pressurizing and mixing, namely adding the magnesium oxide, the rest 7.5 parts of zinc oxide, sulfur, the accelerant and the DCP into an internal mixer for mixing, wherein the top plug pressure is 0.5-0.6MPa, and the mixing time is 3 minutes;

(6) and (3) sheet discharging: and (5) discharging the rubber processed in the step (5) to an open mill, and adjusting the roll spacing to 2mm and lower the sheet.

Comparative example 1

A node rubber composition was the same as in example except that 30 parts by weight of isoprene rubber and 30 parts by weight of epoxidized natural rubber were replaced with 60 parts by weight of natural rubber.

Comparative example No. two

The formula and the preparation method of the positioning node rubber composition are the same as those of the first embodiment, and only the nano-scale silicon dioxide is lacked.

Comparative example No. three

The formula is consistent with the embodiment, the difference is that the preparation method of the positioning node rubber composition is different, the embodiment adopts the traditional process of small material-large material-vulcanizing agent, and the preparation method is as follows:

(1) weighing: weighing the raw materials according to the proportion in the formula;

(2) pretreatment of raw materials: uniformly mixing the carbon black N330, the nano-scale silicon dioxide and the unsaturated carboxylic acid weighed in the step (1), activating for twenty minutes by microwave, and cooling for later use;

(3) primary pressurizing and mixing: chloroprene rubber, isoprene rubber, epoxy natural rubber, stearic acid, polyethylene glycol, an anti-aging agent, microcrystalline wax and calcium oxide are added into an internal mixer for mixing, the top plug pressure is 0.5-0.6MPa, and the mixing time is 5 minutes;

(4) secondary pressurizing and mixing: adding Arabic gum, carbon black N330, nano-scale silicon dioxide, unsaturated carboxylic acid and 7.5 parts of zinc oxide into an internal mixer for mixing, wherein the upper plug pressure is 0.5-0.6MPa, and the mixing time is 3 minutes;

(5) and (3) sheet discharging: discharging the rubber material obtained in the step (3) onto an open mill, turning over the rubber material on the open mill for 4 times, then uniformly adding magnesium oxide, the remaining 7.5 parts of zinc oxide, sulfur, an accelerant and DCP, turning over for 4 times, finally adjusting the roll gap of the open mill to be 0.5mm, and adjusting the roll gap to be 2mm after 5 times of thin passing, and then cooling the sheet.

Comparative example No. four

A positioning node rubber composition is as in the examples in parts by weight.

The preparation method of the positioning node rubber composition is the same as that of the first embodiment, and only the calcium oxide is absent.

Comparative example five

A positioning node rubber composition is as in the examples in parts by weight.

The preparation method of the positioning node rubber composition is the same as that of the first embodiment, and only the Arabic gum is absent.

Comparative example six

A positioning node rubber composition is as in the examples in parts by weight.

A method for preparing a positioning node rubber composition is the same as that of example one, except that step (2) is omitted.

The rubber materials of the embodiment 1 and the comparative examples 1 to 6 are subjected to performance test, wherein the rubber hardness is tested according to a method specified in GB/T531, and the tensile strength and the elongation at break are tested according to a method specified in GB/T528; the compression set was measured according to the method specified in GB/T7759, the ozone resistance was measured according to the method specified in GB/T7762, the electric insulation resistance was measured according to the method specified in GB/T1692, the low-temperature embrittlement temperature was measured according to the method specified in GB/T1682, and the heat aging property was measured according to the method specified in GB/T3512, and the results of the measurements are shown in Table 1.

Table 1:

from the comparison of example 1 with comparative example 1, it can be seen that 20 to 30 parts of isoprene rubber in combination with 10 to 30 parts of epoxy natural rubber and with 40 to 60 parts of chloroprene rubber are much better in dynamic ozone resistance and fatigue resistance than 40 to 60 parts of natural rubber and with 40 to 60 parts of chloroprene rubber.

By comparing example 1 with comparative example 2, it can be seen that the addition of nano-sized silica can significantly improve the tensile strength and electrical insulation properties of the rubber.

By comparing example 1 with comparative example 3, it can be seen that the processing technique employed in the present invention can significantly improve the tensile strength and fatigue resistance of the rubber compared to the conventional processing technique.

By comparing example 1 with comparative example 4, it can be seen that the addition of calcium oxide can significantly improve the tensile strength and fatigue resistance of the rubber because the addition of calcium oxide promotes vulcanization of the rubber, increasing the crosslink density of the rubber.

By comparing example 1 with comparative example 5, it can be seen that the addition of gum arabic can significantly improve the fatigue resistance of the rubber.

By comparing example 1 with comparative example 6, it can be seen that the tensile strength and fatigue resistance of the rubber can be significantly improved by subjecting carbon black N330, nano-silica, and unsaturated carboxylic acid to microwave activation.

The foregoing is only a preferred embodiment of the present invention, and it will be apparent to those skilled in the art that various modifications and improvements can be made without departing from the principle of the invention, and such modifications and improvements are also considered to be within the scope of the invention.