CN113801381A - High-performance aircraft tire tread rubber and preparation method thereof - Google Patents

Abstract

The invention discloses a high-performance aircraft tire tread rubber and a preparation method thereof, wherein the tread rubber takes domestic natural rubber as a raw rubber system, N234 carbon black and cryptocrystalline graphite as a reinforcing system, and cryptocrystalline graphite is adopted to partially replace carbon black, so that the heat generation of the rubber material is reduced while the heat conductivity and tensile strength of the rubber material are improved, and the tread rubber is matched with auxiliary materials such as white carbon black, a novel silane coupling agent, insoluble sulfur, a sulfonamide vulcanization accelerator and the like, so that the rubber material has good comprehensive performance. The rubber material is used as a tread rubber of an aircraft tire, the tire can not have the quality problems of block falling, internal delamination, tread throwing and the like due to high heat generation of the tread under the harsh high-speed and high-load using conditions, and the tire is safe to use.

Description

High-performance aircraft tire tread rubber and preparation method thereof

Technical Field

The invention relates to the technical field of rubber processing and production, in particular to a high-performance aircraft tire tread rubber and a preparation method thereof.

Background

The aviation tire is used as the only contact part of the airplane and the ground, and bears and transfers dynamic and static loads between the airplane and a runway. It is used under the harsh conditions of high speed and high load, and its design and production technology is called pyramid tip in tyre manufacturing industry. The tread rubber is positioned on the outermost layer of the aircraft tire, is directly contacted with a runway, is greatly abraded, torn and extruded, and is a part of the aircraft tire which bears harsher external stress. In addition, because the tread rubs with the ground for a long time to generate heat, hysteresis heat generation caused by the viscoelastic property of rubber is generated, and the rubber is a poor heat conductor, the comprehensive action of the rubber, the viscoelastic property and the heat generation easily causes heat accumulation in the rubber material of the tread rubber, accelerates the aging of the tread and influences the service life of the tire.

Based on the use condition and the use characteristics of the aircraft tire tread rubber, the aircraft tire tread rubber has the advantages of high impact resistance, tearing resistance, puncture resistance, good fatigue resistance, low heat generation, good thermal conductivity, long service life and the like. The development of the aircraft tire tread rubber with high comprehensive performance has great significance for ensuring the safe running of the airplane and prolonging the service life of the tire.

In the rubber industry, carbon black is the most important rubber reinforcing material, improves the processability of rubber compounds, and endows tires with various performances such as good abrasion resistance, tear resistance, heat resistance and the like. However, carbon black has the defects of large processing pollution, large energy consumption, easy flying during addition and the like, and is not beneficial to realizing the development targets of carbon peak reaching and carbon neutralization, so that the search for a material capable of replacing carbon black is an urgent need of the rubber industry. The aphanitic graphite is an allotrope of carbon black, the carbon black and the aphanitic graphite have similar microstructures and excellent thermal conductivity, and are easy to disperse in a rubber matrix after being subjected to ultrafine grinding, so that the natural aphanitic graphite has excellent potential application value as a novel rubber reinforcing filler. The graphite part replaces carbon black to be used as a reinforcing and toughening material of natural rubber, so that the heat conducting property of the rubber material can be improved, the production cost of the aircraft tire can be greatly reduced, the comprehensive utilization of abundant graphite resources in China can be greatly promoted, and the method has important significance in economy and production.

Disclosure of Invention

The invention aims to provide a high-performance aircraft tire tread rubber and a preparation method thereof aiming at the defects of the prior art, the rubber material takes domestic high-end natural rubber as a main material, cryptocrystalline graphite, N234 carbon black, white carbon black, a novel silane coupling agent, insoluble sulfur and a sulfonamide vulcanization accelerator as main auxiliary materials, and is prepared by a certain process according to a certain proportion, so that the high-performance aircraft tire tread rubber has the effects of low heat generation in compression, high heat conductivity, high tensile strength and tear strength and good processability.

The technical scheme for realizing the purpose of the invention is as follows:

the high-performance aircraft tire tread rubber is prepared from the following raw materials in parts by mass:

100 parts of natural rubber, 5-10 parts of white carbon black, 35-40 parts of N234 carbon black, 10-15 parts of cryptocrystalline graphite, 10-42-3 parts of silane coupling agent KH-845, 2 parts of heat stabilizer HS-801, 4-5 parts of zinc oxide, 2 parts of stearic acid, 2-2.5 parts of anti-aging agent 40202, 1-2 parts of anti-aging agent S-RD, 2-4 parts of aromatic oil, 1.5-2 parts of insoluble sulfur, 0.8-1.3 parts of accelerator NOBS and 0.2-0.3 part of anti-scorching agent CTP.

A high-performance aircraft tire tread rubber and a preparation method thereof comprise the following steps:

1) banburying natural rubber in a banbury mixer at a temperature of between 80 and 85 ℃ and between 90 and 95 ℃ to obtain a first banburying material;

2) adding a heat stabilizer, stearic acid, zinc oxide and an anti-aging agent into the first internal mixing material obtained in the step 1) according to a proportion for internal mixing, wherein the internal mixing temperature is increased from 90-95 ℃ to 100-105 ℃, so as to obtain a second internal mixing material;

3) adding white carbon black, a silane coupling agent, N234 carbon black and aphanitic graphite into the second internal mixing material obtained in the step 2) according to a proportion for internal mixing, wherein the internal mixing temperature is 100-105 ℃ and is increased to 140-145 ℃ to prepare a third internal mixing material;

4) discharging the third internal mixing material from the internal mixer, cooling and standing for 24-36 h to obtain a first-stage mixed rubber; the mixing time is about 7 min to 10 min.

5) Adding insoluble sulfur, an accelerant NOBS and an anti-scorching agent into an internal mixer together with the first-stage rubber compound according to a proportion, and mixing at the mixing temperature of 100-105 ℃ to obtain a second-stage rubber compound;

6) and placing the two-stage rubber compound in an open mill, milling a covered roller by 2mm, cutting rubber for 3/4 on the left and right three times respectively, blanking the covered roller by 2mm, and standing for 24-72 h to obtain final rubber compound, namely the tread rubber compound.

The first-stage rubber compound is placed for 16-24 hours before being mixed with insoluble sulfur, an accelerant NOBS and an anti-scorching agent.

According to the high-performance aircraft tire tread rubber and the preparation method thereof, provided by the invention, the high-end domestic natural rubber is used as a raw rubber system, and the high-end domestic natural rubber with the stretching crystallization characteristic shows good impact resistance and has the characteristics of excellent mechanical comprehensive performance and processing performance in the process of large deformation fatigue of rubber materials due to repeated impact. The reinforcing system adopts N234 carbon black and partial aphanitic graphite, the N234 carbon black is super wear-resistant carbon black in a new process high structure, the particles are fine, the structure is high, the internal pores are many, the conductivity is good, the tread rubber added with the N234 carbon black has good fatigue performance and high strength, and the wear resistance and the rebound resilience are obviously improved; the modified aphanitic graphite with rich sections, rough surface and more structural defects is added into rubber to enhance the interface effect of rubber/filler, improve the thermal conductivity and tensile strength of the rubber material and reduce the heat generation of the rubber material. . The white carbon black can obviously improve the tear resistance of the sizing material and reduce the hysteresis heat generation of the sizing material, and the white carbon black and the carbon black are used together to ensure that the sizing material obtains better comprehensive performance. The silane coupling agent KH-845-4 is selected to improve the tensile strength of the rubber, reduce the permanent deformation rate and enhance the wear resistance. The used heat stabilizer HS-80 can inhibit the breakage of polysulfide bonds in vulcanized rubber under severe use conditions, promote the conversion of the polysulfide bonds to disulfide bonds and monosulfide bonds, keep the stable level of the crosslinking density of rubber materials in the use process, improve the retention rate of the physical properties of the vulcanized rubber and prolong the service life of tires. The anti-aging system combining the p-phenylenediamine anti-aging agent 4020 and the ketoamine anti-aging agent S-RD is adopted, the anti-aging agent 4020 has a good protection effect on flex fatigue, thermal oxidation and other aging, the anti-aging agent S-RD has the effects of inhibiting severe oxidation and thermal aging, and has a good protection effect on heat, oxygen, copper, manganese and other harmful metals. The insoluble sulfur is a linear long-chain high-molecular polymer for further processing sulfur, and compared with the common sulfur, the insoluble sulfur can ensure that the adhesive does not frost during the storage process, overcomes the defect of poor adhesive force of the adhesive caused by frost, and is beneficial to forming operation. Aromatic oil is selected as a plasticizer of the sizing material, so that the processing technological performance of the semi-finished product can be improved, and the dimensional stability of the semi-finished product is ensured; the scorch retarder CTP can prolong the scorching time of rubber materials, ensure that the tread rubber materials have sufficient time for mixing and extrusion molding, and greatly improve the processing safety of the rubber materials.

The mutual matching of the materials ensures that the rubber material has good comprehensive performance. The rubber material is used as a tread rubber of an aircraft tire, the tire can not have the quality problems of block falling, internal delamination, tread throwing and the like due to high heat generation of the tread under the harsh high-speed and high-load using conditions, and the tire is safe to use.

Compared with the prior art, the invention has the beneficial effects that:

1. the tread rubber for the aircraft tire prepared by the invention has the characteristics of low heat generation, high thermal conductivity, excellent physical and mechanical properties, easiness in processing and the like, improves the production safety and the production efficiency, and reduces the production cost and the energy consumption.

2. The invention adopts domestic high-end natural rubber, thus solving the problem of localization of the use of raw materials; the prepared tread rubber can meet the performance requirements of high speed and high load of novel aviation tires in the future.

3. The cryptocrystalline graphite used in the invention has wide sources and low price, and when the cryptocrystalline graphite is applied to an aircraft tire rubber material, the rubber material has excellent mechanical comprehensive performance, low heat generation and good heat conduction performance, and the application field of the cryptocrystalline graphite is expanded, so that the production cost of the aircraft tire is reduced.

Drawings

FIG. 1 is an SEM image of cryptocrystalline graphite; FIG. 2 is an SEM image of a vulcanizate prepared according to the formulation of example 1.

Detailed Description

The present invention will be further illustrated with reference to the following examples, but is not limited thereto.

Example (b):

by adopting the raw materials in the technical scheme, the following examples 1-3 and comparative example 1 are prepared in parts by mass:

TABLE 1 amount of each raw material used in examples and comparative examples

Name of raw material	Example 1	Example 2	Example 3	Comparative example 1
					Domestic high-end natural rubber	100	100	100	100
White carbon black	5	8	10	8
					N234 carbon Black	40	38	35	50
Cryptocrystalline graphite	10	10	15	0
					Silane coupling agent KH-845-4	2	3	3	2
Heat stabilizer HS-80	1.0	1.0	1.5	1.0
					Zinc oxide	5	4	5	4
Stearic acid	2	2	2	2
					Anti-aging agent 4020	2.5	2.5	2.0	2.5
Anti-aging agent S-RD	1.0	1.4	2.0	1.4
					Aromatic oil	4	2	2	2
Insoluble sulfur	2	1.8	1.5	1.8
					Accelerant NOBS	0.8	1.0	1.3	1.0
Scorch retarder CTP	0.2	0.3	0.3	0.3

Preparing the raw materials listed in the above examples 1-3 and comparative example 1 into an aircraft tire tread rubber material according to the following steps:

first-stage mixing:

(1) adding the natural rubber plasticated rubber into an internal mixer, wherein the mixing temperature is increased from 80-85 ℃ to 90-95 ℃;

(2) putting the heat stabilizer, stearic acid, zinc oxide and the anti-aging agent into an internal mixer according to a proportion, mixing and banburying, wherein the mixing temperature is increased from 90-95 ℃ to 100-105 ℃;

(3) adding white carbon black, a silane coupling agent, N234 carbon black and aphanitic graphite into an internal mixer according to a ratio, mixing and banburying, wherein the mixing temperature is increased from 100-105 ℃ to 140-145 ℃;

(4) discharging the mixture from the internal mixer to the upper and lower sheets of the tablet press when the mixing temperature reaches 140-145 ℃, cooling, and standing for 24-36 h at 25 ℃, wherein the rubber is a section of rubber compound; the mixing time is about 7 min to 10 min.

And (3) second-stage mixing:

(1) placing the first-stage rubber compound for 16-24 h (placing for a period of time after mixing is favorable for rubber and carbon black to form a combined rubber and improve the performance of the rubber compound), putting the insoluble sulfur, the accelerator NOBS and the scorch retarder into an internal mixer together with the first-stage rubber compound according to the proportion, and mixing and internally mixing to 100-105 ℃;

(2) discharging the mixture from the internal mixer to an open mill, carrying out 2mm open mill roll wrapping, carrying out rubber tapping for 3/4 on the left and the right three times respectively, carrying out sheet cutting on the 2mm roll wrapping, standing at 25 ℃ for 24-72 h, and obtaining final rubber, namely: a tread mix.

The SEM image of the aphanitic graphite used in examples 1 to 3 is shown in fig. 1, and it can be seen from the figure that the aphanitic graphite used in the present invention has rich cross section, rough surface, obvious graphite lamellar structure and many structural defects, and the addition of the graphite to rubber can enhance the rubber/filler interface effect.

The SEM image of the tread rubber prepared in example 1 is shown in FIG. 2, and it can be seen from the SEM rubber prepared by the process that the filler is uniformly dispersed, and the aphanitic graphite is completely embedded in the rubber matrix and shows strong interface action with the rubber matrix.

The performance test of the rubber compound prepared in the above examples 1 to 3 and comparative example 1 is performed, and the results are shown in the following table 2:

table 2 comparative tables of rubber properties of examples and comparative examples

Item	Single position	Example 1	Example 2	Example 3	Comparative example 1
						Tensile strength	MPa	29	30	31	28
Elongation at break	%	560	589	600	541
						Tear strength	MPa	115	118	120	95
Compression fatigue temperature rise	℃/25min	31	30	28	33
						Thermal conductivity	W/（m﹒K）	0.31	0.33	0.34	0.23
Akron abrasion loss	cm3/1.61km	0.10	0.13	0.15	0.11
						Cutting reduction	g	0.95	1.11	1.20	0.89

From the performance results, compared with vulcanized rubber reinforced by only using carbon black, the prepared aircraft tire tread rubber has higher tensile strength, elongation at break and tearing strength, lower heat generation, obviously improved heat conducting performance and better puncture resistance by partially replacing the carbon black with the cryptocrystalline graphite.

Claims (3)

1. The high-performance aircraft tire tread rubber is prepared from the following raw materials in parts by mass:

100 parts of natural rubber, 5-10 parts of white carbon black, 35-40 parts of N234 carbon black, 10-15 parts of cryptocrystalline graphite, 10-42-3 parts of silane coupling agent KH-845, 2 parts of heat stabilizer HS-801, 4-5 parts of zinc oxide, 2 parts of stearic acid, 2-2.5 parts of anti-aging agent 40202, 1-2 parts of anti-aging agent S-RD, 2-4 parts of aromatic oil, 1.5-2 parts of insoluble sulfur, 0.8-1.3 parts of accelerator NOBS and 0.2-0.3 part of anti-scorching agent CTP.

2. The high-performance aircraft tire tread rubber and the preparation method thereof as claimed in claim 1, wherein the preparation method of the tread rubber comprises the following steps:

1) banburying natural rubber in a banbury mixer at a temperature of between 80 and 85 ℃ and between 90 and 95 ℃ to obtain a first banburying material;

2) adding a heat stabilizer, stearic acid, zinc oxide and an anti-aging agent into the first internal mixing material obtained in the step 1) according to a proportion for internal mixing, wherein the internal mixing temperature is increased from 90-95 ℃ to 100-105 ℃, so as to obtain a second internal mixing material;

3) adding white carbon black, a silane coupling agent, N234 carbon black and aphanitic graphite into the second internal mixing material obtained in the step 2) according to a proportion for internal mixing, wherein the internal mixing temperature is 100-105 ℃ and is increased to 140-145 ℃ to prepare a third internal mixing material;

4) discharging the third internal mixing material from the internal mixer, cooling and standing for 24-36 h to obtain a first-stage mixed rubber; the mixing time is about 7 min to 10 min;

5) adding insoluble sulfur, an accelerant NOBS and an anti-scorching agent into an internal mixer together with the first-stage rubber compound according to a proportion, and mixing at the mixing temperature of 100-105 ℃ to obtain a second-stage rubber compound;

6) and placing the two-stage rubber compound in an open mill, milling a covered roller by 2mm, cutting rubber for 3/4 on the left and right three times respectively, blanking the covered roller by 2mm, and standing for 24-72 h to obtain final rubber compound, namely the tread rubber compound.

3. The high-performance aircraft tire tread rubber and the preparation method thereof as claimed in claim 2, wherein the first-stage rubber compound is parked for 16-24 h before being mixed with insoluble sulfur, an accelerator NOBS and a scorch retarder.

Images