Aerospace radial tire crown belt strip adhesive and method of making

Abstract

The application belongs to the technical field of rubber, and discloses an aviation radial tire crown strip adhesive and a preparation method thereof. The aviation radial tire crown strip adhesive is prepared by mixing main materials of domestic natural rubber, auxiliary materials of fast extrusion carbon black, high-dispersion white carbon black, white carbon black dispersing agent, silane coupling agent, adhesive, thermal stabilizer, heat-conducting reinforcing agent and anti-reversion agent according to specific weight proportions, and is manufactured into a mixing rubber through processes such as mixing of a density mixer and filtering of a filter. The mixing rubber is manufactured into a rubber semi-finished product in an extrusion mode by using an extruder, and is used for crown strip extrusion. The crown strip adhesive prepared by the application has low heat generation, high tear strength, high adhesive strength and good thermal stability, and is more suitable for the requirements of high speed and high load of new models on tires. The rubber has low shrinkage and good adhesive performance, and the performance retention rate of the rubber is high during use, thereby improving the use safety and service life of the tire.

Description

Technical Field

[0001] This invention relates to aircraft radial tires, specifically a low-shrinkage aircraft radial tire crown belt adhesive and its preparation method. Background Technology

[0002] Because aircraft tires are high-speed, high-load tires, with speeds exceeding 360 km / h being commonplace, they require greater restraint to suppress the enormous centrifugal force generated during high-speed, high-load rotation. The belt layer structure of aircraft radial tires effectively tightens the tire carcass and distributes stress. The belt layer is typically applied using a ply bonding method, which is simple and easy to operate. However, this method has several drawbacks: 1. It easily forms small air bubbles; 2. It is prone to delamination, leading to tire tread slippage during use due to delamination of the bonding surfaces; 3. The ply bonding method results in many fabric ends at the cut points with less adhesive, leading to poor adhesion and easy delamination at the fabric ends under load and high-speed rotation.

[0003] The existing belt layer is calendered, while the crown strip of the winding method is extruded. This places higher demands on the performance of the adhesive. When the belt layer adhesive formulation is extruded, there is a serious shrinkage problem, which makes it unsuitable for winding. This is also the main problem of the existing technology. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a low-shrinkage crown strip adhesive for aircraft radial tires using a belt layer winding method, and its preparation method.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A method for preparing an adhesive for the crown strip of an aircraft radial tire, wherein the adhesive raw materials include domestic natural rubber, reinforcing agent, highly dispersible silica, silica dispersant, silane coupling agent, adhesive, nano zinc oxide, stearic acid, p-phenylenediamine antioxidant 4020, ketone amine antioxidant RD, heat stabilizer, thermal conductivity enhancer and anti-reversion agent, insoluble sulfur HDOT-20, sulfenamide accelerator NS, and scorching inhibitor CTP;

[0007] (1) The adhesive is a mixture of SL3022 and adhesive Y, with the addition of curing agent SL-RA65.

[0008] (2) The binder Y is prepared by ball milling resorcinol, accelerator H and silica in a mass ratio of 1:1:1.2 to 1.6 and drying in an oven at 90 to 110°C for 2 hours. The particle size of the binder Y is 1-3 nm and the ball-to-material ratio is between 8 and 10:1 during the ball milling process.

[0009] (3) The reinforcing agent is one or both of the fast-extrusion carbon black N550 and N660;

[0010] (4) Anti-sulfurization reversion agent WK901 and heat stabilizer HS-80 are used together;

[0011] (5) The reinforcing agent is fast extrusion carbon black N550 and / or N660, and is used in combination with highly dispersible silica;

[0012] (6) The silane coupling agent is silane coupling agent KH550.

[0013] The natural rubber is domestically produced granulated rubber, with GCR rubber being the preferred choice and RTJ rubber as a secondary choice.

[0014] The aviation radial tire crown strip adhesive of this invention uses domestic natural rubber as the main material, and fast-extruded carbon black, highly dispersed silica, silica dispersant, adhesive, silane coupling agent, heat stabilizer, thermal conductivity enhancer and anti-sulfurization reversion agent as auxiliary materials. The materials are mixed according to the following weight ratio (see Table 1), and the mixture is manufactured by internal mixer mixing, filter filtering and other processes. The mixture is then extruded by an extruder to make a semi-finished rubber compound for crown strip extrusion.

[0015] Table 1. Proportions of Components in the Adhesive for Crown Strips of Aviation Radial Tires

[0016] raw material Parts by weight (portions) Natural rubber 100 Reinforcing agent 30～60 Highly dispersible silica 5～15 precipitate dispersant 1～3 Silane coupling agent 1～4 Heat stabilizer HS-80 0.5～3 Thermal conductivity enhancer TB-S 0.5～2 Nano zinc oxide 2～5 stearic acid 0.5～3 p-Phenylenediamine antioxidant 4020 1～4 Ketone amine antioxidants RD 1～4 Adhesive resin SL3022 0.5～3 Adhesive Y 0.5～3 Resin curing agent SL-RA65 0.5～3 Insoluble sulfur HDOT-20 1～4 sulfenamide accelerator NS 0.5～3 Anti-sulfurization reversion agent WK-901 0.5～1 CTP (Catalyst) 0.1～0.4

[0017] The natural rubber used has good overall properties, low heat generation, high tensile strength, high elongation, and good processing performance. The reinforcing system uses fast-extruded carbon black and highly dispersible silica, with the addition of coupling agents. Coupling agents can improve the tensile strength and tear strength of the rubber compound while reducing heat generation. Heat stabilizers and thermal conductive agents are added to improve the thermal stability and heat dissipation performance of the rubber compound. By adjusting the ratio of sulfur accelerators, the content of monosulfide and polysulfide bonds is adjusted. Polysulfide bonds can improve the elasticity and tear resistance of the rubber compound and reduce heat generation, while monosulfide bonds can improve the aging performance of the rubber compound. Polysulfide bonds have poor stability and are easily degraded. Coupling agents and anti-reversion agents can act as sulfur donors to insert into the polysulfide crosslinking bonds, allowing the modified main chain to be stitched together again.

[0018] The preparation process of the adhesive for the crown strip of the aircraft radial tire in this invention is as follows:

[0019] (1) A stage of mixing

[0020] Add the required parts by weight of natural rubber, nano zinc oxide, stearic acid, adhesive resin SL3022, p-phenylenediamine antioxidant 4020, and ketone amine antioxidant RD to a mixer and mix at a speed of 30-50 rpm. When mixing for 140-160 seconds, add the required parts by weight of reinforcing agent, highly dispersible silica, silane coupling agent KH550, and silica dispersant. Adjust the mixing speed to 70-80 rpm and rapidly raise the mixing temperature to 185-190℃. Raise the top bolt and simultaneously spray cold water onto the outer wall of the mixing chamber for 5-10 seconds to lower the rubber compound temperature to 130-140℃. Lower the top bolt and restore the speed to 30-50 rpm. Continue mixing for 280-300 seconds, and discharge the rubber when the mixing temperature reaches 150-160℃. Let it cool and stand for 8-16 hours to obtain a first-stage compound.

[0021] (2) Two-stage mixing

[0022] Add the first stage of compound rubber to the internal mixer for hot refining at a speed of 20-30 rpm for 160-200 seconds. When the temperature reaches 90-105℃, discharge the rubber and filter it using a filter with a mesh size of 40-80. Let the filtered rubber stand for 8-24 hours to obtain the second stage of compound rubber.

[0023] (3) Three-stage mixing

[0024] Heat stabilizer HS-80, thermal conductivity enhancer TB-S, resin curing agent SL-RA65, adhesive Y, insoluble sulfur HDOT-20, accelerator NS, anti-sulfurization reversion agent WK-901, anti-scorching agent CTP, and the second-stage compound are added to a Banbury mixer and mixed at a speed of 10-25 rpm for 180-220 seconds. The mixing temperature is raised to 95-100℃ and the mixture is discharged. After cooling and standing for 8-16 hours, the third-stage compound is obtained. The compound is then extruded through an extruder to form strips 40-80 mm wide and 10-30 mm thick to obtain crown strip adhesive film.

[0025] (4) The crown band adhesive film obtained in step (3) is extruded and compounded with 4-7 polyamide 66 cords using a twin-screw extruder to obtain the final crown band adhesive strip.

[0026] In step (4), the extrusion temperature of the twin-screw extruder is 75-85℃ and the extrusion speed is 5-15 m / min.

[0027] The adhesive strip prepared using the formulation of the crown strip of this invention exhibits low heat generation, high bonding strength, high tear strength, and good thermal stability, making it more suitable for the high-speed, high-load requirements of aviation radial tires. The rubber compound has low heat generation during compression, good heat transfer, and high bonding strength with the cord. Its performance is less prone to degradation during use, resulting in safer tire operation. Specific performance details are shown in Table 2 below.

[0028] Table 2. Performance of crown strip adhesive strips prepared using the crown strip adhesive formulation of this invention for aircraft radial tires.

[0029] project Performance range Tensile strength, MPa 21.0～28.0 Elongation at break, % 400～550 300% constant tensile stress, MPa 15.0～18.0 Tear strength, kN / m 100～150 Compression fatigue heat generation, ℃ 10～20 Adhesive strength of the adhesive thread, N 200～230 Torque curve change rate of sulfur translucency analyzer at 143℃ for 60 minutes -15～-5 Elongation change rate after aging in hot air at 100℃ for 24 hours -20～-10 Mooney viscosity ML1+4 (100℃) 60～80

[0030] Tensile strength, elongation at break, and stress at 300% constant elongation shall be tested in accordance with GB / T528-2009; tear strength shall be tested in accordance with GB / T529-2009; heat generation during compression fatigue shall be tested in accordance with GB / T1687.3; Mooney viscosity shall be tested in accordance with GB / T1232.1; adhesive strength of the adhesive thread shall be tested in accordance with GB / T2942; sulfurization performance shall be tested in accordance with GB / T16584; and hot air aging test shall be tested in accordance with GB / T3512.

[0031] The beneficial effects of the present invention are as follows: the crown belt strip prepared by the crown belt strip rubber compound formulation of the present invention has stable dimensions, good adhesion performance and low heat generation. The belt layer is formed by winding, which reduces the problem of too many ends between the plies, solves the problem of uneven tire stress, and reduces the risk of tire slippage caused by high speed and high load. Detailed Implementation

[0032] The present invention will be further illustrated by the following examples.

[0033] Examples 1-3

[0034] The crown strip adhesive for aircraft radial tires in Examples 1-3 is prepared by mixing the following materials and weight proportions (see Table 3) in an internal mixer to produce a compound. The compound is then extruded into a semi-finished rubber strip using an extruder. The strip is then extruded on a twin-screw extruder and bonded to the cord to produce crown strip adhesive cord, which is used for aircraft radial tire molding.

[0035] Table 3. Weight proportions of each component in the adhesive for the crown strip of aircraft radial tires in Examples 1-3

[0036] raw material Example 1 Example 2 Example 3 Domestic natural rubber GCR-2 100 100 100 Fast-pressed carbon black N550 50 40 60 Highly dispersible silica 8 10 5 Silica dispersant (FS-78) 3 2 1 Silane coupling agent KH550 3 3 1 Heat stabilizer HS-80 1.5 0.5 1 Thermal conductivity enhancer TB-S 1.5 1 0.5 Nano zinc oxide 4 3 3 stearic acid 2 1 1 p-Phenylenediamine antioxidant 4020 2 1 1.5 Ketone amine antioxidants RD 2 1.5 1 Adhesive resin SL3022 1 0.5 2 Adhesive Y 1 2.9 0.5 Resin curing agent SL-RA65 1 0.5 1 Insoluble sulfur HDOT-20 2.5 3 2 sulfenamide accelerator NS 1 0.8 0.5 Anti-sulfurization reversion agent WK-901 1 0.8 0.5 CTP (Catalyst) 0.2 0.1 0.1

[0037] The crown band strip adhesive materials of Examples 1-3 of this invention are prepared using the following method: first, adhesive Y is prepared, then multi-stage mixing is performed using an internal mixer, and the crown band strip adhesive is obtained by extrusion using an extruder; the specific process is as follows:

[0038] 1. Material preparation: Preparation of adhesive Y: Resorcinol (particle size 30-60nm), accelerator H (particle size 3mm-100μm) and silica (particle size 10-20nm) were ball-milled at 80 rpm for 25 minutes in a mass ratio of 1:1:1.44, with a ball-to-material ratio of 9:1. After ball milling, the mixture was dried in an oven at 100℃ for 2 hours to obtain adhesive Y, which has a particle size of 1-3nm.

[0039] 2. The preparation method of the crown strip adhesive is as follows:

[0040] (1) First stage of mixing: The domestic natural rubber GCR-2, nano zinc oxide, stearic acid, adhesive resin SL3022, p-phenylenediamine antioxidant 4020, and ketone amine antioxidant RD required by weight ratio are added to the internal mixer for mixing. The mixing speed is 40 rpm. When the mixing reaches 150 seconds, fast extrusion carbon black N550, high dispersibility silica, silane coupling agent KH550 and silica dispersant FS-78 are added. The mixing speed is adjusted to 75 rpm. The mixing temperature rises rapidly to 187°C. The top bolt is raised and the outer wall of the mixing chamber is sprayed with cold water for 8 seconds to reduce the rubber temperature to 131°C. The top bolt is lowered and the speed is restored to 40 rpm. Mixing continues for 300 seconds. The mixing temperature reaches 160°C and the rubber is discharged. The mixture is cooled and left to stand for 12 hours to obtain the first stage of mixed rubber.

[0041] (2) Two-stage mixing: The first-stage compound is added to the internal mixer for hot mixing. The hot mixing speed is 30 rpm, the hot mixing time is 160 seconds, the hot mixing temperature is 100℃, and the compound is discharged. The compound is filtered using a filter with a mesh size of 60 mesh. The filtered compound is left to stand for 20 hours to obtain the second-stage compound.

[0042] (3) Three-stage mixing: Heat stabilizer HS-80, thermal conductivity enhancer TB-S, resin curing agent SL-RA65, adhesive Y, insoluble sulfur HDOT-20, accelerator NS, anti-sulfurization reversion agent WK-901, anti-scorching agent CTP, and two-stage compound are added to the internal mixer for mixing. The mixing speed is 20 rpm, the mixing time is 200 seconds, and the mixing temperature is 100℃. The rubber is discharged and cooled and left to stand for 16 hours to make the various additives more evenly dispersed in the rubber to obtain three-stage compound. The compound is extruded into a 70mm wide and 20mm thick sheet for later use.

[0043] (4) The spare film obtained in step (3) is extruded and compounded with 6 polyamide 66 cords using a twin-screw extruder. The extrusion temperature is 80℃ and the extrusion speed is 10 m / min to obtain the final crown strip adhesive strip.

[0044] The performance test results of the crown band adhesive strips prepared according to the formulations of Examples 1-3 above are shown in Table 4.

[0045] Table 4. Performance of the adhesive strips for the crown strips of aircraft radial tires prepared according to the formulations in Examples 1-3.

[0046] project Example 1 Example 2 Example 3 Tensile strength, MPa 26.6 23.3 25.2 Elongation at break, % 494 438 501 300% constant tensile stress, MPa 15.9 17.8 15.3 Tear strength, kN / m 132 126 117 Compression fatigue heat generation, ℃ 14 15 16 Adhesive strength of the adhesive thread, N 230 203 219 Torque curve change rate of sulfur translucency analyzer at 143℃ for 60 minutes -7 -12 -10 Elongation change rate after aging in hot air at 100℃ for 24 hours -11 -17 -16 Mooney viscosity ML1+4 (100℃) 65 72 64

[0047] In the formulations of the crown strip adhesive strips in Examples 1-3, a ball-milled compounded adhesive Y is introduced. Ball milling reduces the particle size and makes the particle size distribution more uniform, resulting in more uniform dispersion in the rubber compound during adhesive preparation. This leads to more cross-linking bonds formed during vulcanization. Furthermore, during the mixing process, after adding the reinforcing agent and silane coupling agent KH550 in the first stage of mixing, the rotation speed is increased to increase the shear force during mixing, rapidly incorporating materials such as carbon black and silica into the rubber and improving its dispersibility. Subsequent cooling with cold water rapidly lowers the temperature of the rubber compound, prolonging the mixing time and improving the uniformity of mixing. Simultaneously, the raising of the top plug allows air to enter the mixing chamber, ensuring continuous mixing in an aerobic environment. The presence of oxygen allows for more complete chain scission of rubber macromolecules, resulting in the formation of more "bound rubber" between the rubber and carbon black. The longer mixing time and the greater amount of "bound rubber" endow the compound with superior mechanical properties. The crown belt strips extruded using the formulations and preparation methods of Examples 1-3 exhibit low heat generation, high adhesion, and good dimensional stability. The crown belt strip adhesive strips prepared in Examples 1 / 2 / 3 showed shrinkage rates of 0.8%, 0.9%, and 0.9% respectively at 177℃ for 2 minutes, all less than 1%. After winding the belt layer using an aviation radial two-stage forming machine, 1030×350R500 aviation radial tires were produced. The outer edge dimensions of the finished tire showed no significant change after vulcanization, as detailed in Table 5 below.

[0048] Table 5 shows the outer dimensions of finished tires prepared using the crown strip adhesives prepared in Examples 1-3.

[0049] Tire size standard Example 1 Example 2 Example 3 Inflatable outer diameter, mm 995±10 996 998 987 Inflatable cross-section width, mm 317±8 318 320 315

[0050] Comparative Example 1

[0051] The formulation of the adhesive for the crown strip of the aircraft radial tire in Comparative Example 1 differs from that in Example 1 in that the same amount of resorcinol is used instead of adhesive Y in Example 1. The other components and proportions in the formulation are the same as in Example 1, and the preparation process is the same as in Example 1.

[0052] Comparative Example 2

[0053] The formulation of the aviation radial tire crown strip adhesive in Comparative Example 2 differs from that in Example 1 in that the preparation of adhesive Y is different from that in Example 1, while the other components and proportions in the formulation are the same as in Example 1, and the preparation process is the same as in Example 1.

[0054] The preparation process of adhesive Y in this comparative example is as follows: resorcinol, accelerator H and silica are mixed in a conventional manner at a mass ratio of 1:1:1.44 without ball milling. Other components and proportions in the formulation are the same as in Example 1, and the preparation process is the same as in Example 1.

[0055] Comparative Example 3

[0056] The formulation of the aviation radial tire crown strip adhesive in Comparative Example 3 differs from that in Example 1 in that the ratio of the three components in adhesive Y is different from that in Example 1, while the other components and their ratios are the same as in Example 1, and the preparation process is the same as in Example 1.

[0057] The preparation process of adhesive Y in this comparative example is as follows: resorcinol, accelerator H and silica are ball-milled at 50 rpm for 10 minutes in a mass ratio of 1:1:0.5, with a particle size of 10-15 nm and a ball-to-material ratio of 8:1. After drying in an oven at 100°C for 2 hours, adhesive Y is obtained.

[0058] Comparative Example 4

[0059] The formulation of the low-shrinkage aircraft radial tire crown strip adhesive in Comparative Example 4 differs from that in Example 1 in that the amount of carbon black N500, the amount of silica, and the amount of insoluble sulfur HDOT-20 are different, while the rest are the same as in Example 1, and the preparation process is the same as in Example 1.

[0060] Comparative Example 5

[0061] The formulation of the low-shrinkage aviation radial tire crown strip adhesive in Comparative Example 5 differs from that in Example 1 in that the amount of highly dispersed silica, silica dispersant, and silane coupling agent are different, and the amount of resin curing agent is also different. Otherwise, it is the same as in Example 1, and the preparation process is the same as in Example 1.

[0062] The adhesive formulations for the crown strips of aviation radial tires in Comparative Examples 1-5 are shown in Table 6.

[0063] Table 6. Weight proportions of each component in the adhesive for the crown strip of aircraft radial tires in Comparative Examples 1-5

[0064] raw material Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Domestic natural rubber GCR-2 100.00 100.00 100.00 100.00 100.00 Fast-pressed carbon black N550 50．00 50.00 50.00 25.00 50.00 Highly dispersible silica 8.00 8.00 8.00 20.00 4.00 precipitate dispersant 3.00 3.00 3.00 3.00 0.80 Silane coupling agent 3.00 3.00 3.00 3.00 0.50 Heat stabilizer HS-80 1.50 1.50 1.50 1.50 1.50 Thermal conductivity enhancer TB-S 1.50 1.50 1.50 1.50 1.50 Nano zinc oxide 4.00 4.00 4.00 4.00 4.00 stearic acid 2.00 2.00 2.00 2.00 2.00 p-Phenylenediamine antioxidant 4020 2.00 2.00 2.00 2.00 2.00 Ketone amine antioxidants RD 2.00 2.00 2.00 2.00 2.00 Adhesive resin SL3022 1.00 1.00 1.00 1.00 0.20 Adhesive Y 0 1.00 1.00 1.00 0.20 Adhesive resorcinol 1.00 0 0 0 0 Resin curing agent SL-RA65 1.00 1.00 1.00 1.00 4.00 Insoluble sulfur HDOT-20 2.50 2.50 2.50 4.50 2.50 sulfenamide accelerator NS 1.00 1.00 1.00 1.00 1.00 Anti-reversion agent WK-901 1.00 1.00 1.00 1.00 1.00 CTP (Catalyst) 0.20 0.20 0.20 0.20 0.20

[0065] The preparation method of the crown strip adhesive film of Comparative Examples 1-5 is the same as that of Examples 1-3. The internal mixer is still used for multi-stage mixing to produce a compound. The compound is then extruded into a semi-finished rubber strip by an extruder. The strip is then extruded on a twin-screw extruder and bonded to the cord to produce a crown strip adhesive composition cord for use in the molding of aviation radial tires. The preparation parameters are the same as those of Examples 1-3.

[0066] The performance test results of the crown band adhesive strips prepared in Comparative Examples 1-5 are shown in Table 7.

[0067] Table 7 Performance of the adhesive strips for the crown strips of aircraft radial tires in Comparative Examples 1-5

[0068] project Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Tensile strength, MPa 24.6 22.3 21.2 18.2 22.1 Elongation at break, % 374 368 407 346 413 300% constant tensile stress, MPa 17.9 13.8 9.7 16.3 10.8 Tear strength, kN / m 88 96 91 65 77 Compression fatigue heat generation, ℃ 35 39 22 52 32 Adhesive strength of the adhesive thread, N 150 143 156 117 123 Torque curve change rate of sulfur translucency analyzer at 143℃ for 60 minutes -18 -25 -19 -28 -26 Elongation change rate after aging in hot air at 100℃ for 24 hours -24 -32 -26 -36 -27 Mooney viscosity ML1+4 (100℃) 75 54 65 85 75

[0069] The crown belt strips extruded using the formulations and preparation methods of Comparative Examples 1-5 exhibited high heat generation, poor adhesion, and significant dimensional changes. The shrinkage rates of the crown belt strip adhesive strips prepared in Comparative Examples 1-5 at 177℃ for 2 minutes were 2.1%, 3.5%, 4.8%, 4.1%, and 3.9%, respectively. After winding the belt layer using an aviation radial two-stage forming machine, 1030×350R500 aviation radial tires were produced. After vulcanization, the outer dimensions of the finished tires changed significantly, with a smaller outer diameter and narrower cross-sectional width, failing to meet tire design requirements (see Table 8 for details).

[0070] Table 8 Outer dimensions of finished tires prepared using the crown strip adhesives prepared in Comparative Examples 1-5

[0071] Tire size standard Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Inflatable outer diameter, mm 995±10 981 978 968 973 979 Inflatable cross-section width, mm 317±8 305 298 301 294 302

[0072] Analysis of Examples 1-3 and Comparative Examples 1-5 shows that, compared with Comparative Examples 1-5, the adhesive bonding strength, tear strength, heat generation, and Mooney viscosity of the examples are high, and the outer edge dimensions of the finished tires meet the standard requirements. In contrast, the adhesive bonding strength, tear strength, and heat generation of the comparative examples are low, and the Mooney viscosity is either too high or too low. As a result, the outer diameter and cross-sectional width of the finished tires are too small and cannot meet the requirements.

[0073] Comparative Example 6

[0074] 1. The formulation of the crown strip adhesive is the same as that in Example 1, and the preparation of adhesive Y is the same as that in Example 1;

[0075] 2. The preparation method of the crown strip adhesive is as follows:

[0076] (1) First stage of mixing: domestic natural rubber GCR-2, nano zinc oxide, stearic acid, adhesive resin SL3022, p-phenylenediamine antioxidant 4020, and ketone amine antioxidant RD are added to the internal mixer for mixing. The mixing speed is 40 rpm. When the mixing reaches 150 seconds, fast extrusion carbon black N550, high dispersibility silica, silane coupling agent KH550 and silica dispersant FS-78 are added. The mixing continues until 260 seconds. The mixing temperature is 160℃ and the rubber is discharged. After cooling and standing for 12 hours, the first stage of mixed rubber is obtained.

[0077] (2) Two-stage mixing: The first-stage compound is added to the internal mixer for hot mixing at a speed of 30 rpm for 160 seconds. The compound is discharged when the temperature reaches 100°C. The compound is then filtered using a filter with a mesh size of 60. The filtered compound is left to stand for 20 hours to obtain the second-stage compound.

[0078] (3) Three-stage mixing: Heat stabilizer HS-80, thermal conductivity enhancer TB-S, resin curing agent SL-RA65, adhesive Y, insoluble sulfur HDOT-20, accelerator NS, anti-sulfurization reversion agent WK-901, anti-scorching agent CTP, and two-stage compound are added to the internal mixer for mixing. The mixing speed is 20 rpm, the mixing time is 200 seconds, and the mixing temperature is 100℃. The rubber is discharged and cooled and left to stand for 16 hours to make the various additives more evenly dispersed in the rubber to obtain three-stage compound. The compound is extruded into rubber strips with a width of 70mm and a thickness of 20mm by an extruder for later use.

[0079] (4) The spare film obtained in step (3) is extruded and compounded with 6 polyamide 66 cords using a twin-screw extruder. The extrusion temperature is 80℃ and the extrusion speed is 10 m / min to obtain the final crown strip adhesive strip.

[0080] Comparative Example 7

[0081] 1. The formulation of the crown strip adhesive is the same as that in Example 1, and the preparation of adhesive Y is the same as that in Example 1;

[0082] 2. The preparation method of the crown strip adhesive is as follows:

[0083] (1) First stage of mixing: The domestic natural rubber GCR-2, nano zinc oxide, stearic acid, adhesive resin SL3022, p-phenylenediamine antioxidant 4020, and ketone amine antioxidant RD required by weight ratio are added to the internal mixer for mixing. The mixing speed is 40 rpm. When the mixing reaches 150 seconds, fast extrusion carbon black N550, high dispersibility silica, silane coupling agent KH550 and silica dispersant FS-78 are added. The mixing speed is adjusted to 75 rpm. The mixing temperature rises rapidly to 175°C. The top bolt is raised and the outer wall of the mixing chamber is sprayed with cold water for 8 seconds to reduce the rubber temperature to 125°C. The top bolt is lowered and the speed is restored to 40 rpm. Mixing continues for 300 seconds. The mixing temperature reaches 150°C and the rubber is discharged. The mixture is cooled and left to stand for 12 hours to obtain the first stage of mixed rubber.

[0084] (2) Two-stage mixing: The first-stage compound is added to the internal mixer for hot mixing at a speed of 30 rpm for 160 seconds. The compound is discharged when the temperature reaches 80°C. The compound is then filtered using a filter with a mesh size of 60. The filtered compound is left to stand for 20 hours to obtain the second-stage compound.

[0085] (3) Three-stage mixing: Heat stabilizer HS-80, thermal conductivity enhancer TB-S, resin curing agent SL-RA65, adhesive Y, insoluble sulfur HDOT-20, accelerator NS, anti-sulfurization reversion agent WK-901, anti-scorching agent CTP, and two-stage compound are added to the internal mixer for mixing. The mixing speed is 20 rpm, the mixing time is 200 seconds, and the mixing temperature is 80℃. The rubber is discharged and cooled and left to stand for 16 hours to make the various additives more evenly dispersed in the rubber to obtain three-stage compound. The compound is extruded into strips with a width of 70mm and a thickness of 20mm by an extruder for later use.

[0086] (4) The spare film obtained in step (3) is extruded and compounded with 6 polyamide 66 cords using a twin-screw extruder. The extrusion temperature is 80℃ and the extrusion speed is 10 m / min to obtain the final crown strip adhesive strip.

[0087] Comparative Example 8

[0088] 1. The formulation of the crown strip adhesive is the same as that in Example 1, and the preparation of adhesive Y is the same as that in Example 1;

[0089] 2. The preparation method of the crown strip adhesive is as follows:

[0090] (1) First stage of mixing: The domestic natural rubber GCR-2, nano zinc oxide, stearic acid, adhesive resin SL3022, p-phenylenediamine antioxidant 4020, and ketone amine antioxidant RD required by weight ratio are added to the internal mixer for mixing. The mixing speed is 40 rpm. When the mixing reaches 150 seconds, fast extrusion carbon black N550, high dispersibility silica, silane coupling agent KH550 and silica dispersant FS-78 are added. The mixing speed is adjusted to 85 rpm. The mixing temperature rises rapidly to 195℃. The top bolt is raised and the outer wall of the mixing chamber is sprayed with cold water for 8 seconds to reduce the rubber temperature to 145℃. The top bolt is lowered and the speed is restored to 40 rpm. Mixing continues for 300 seconds. The mixing temperature reaches 165℃ and the rubber is discharged. The mixture is cooled and left to stand for 12 hours to obtain the first stage of mixed rubber.

[0091] (2) Two-stage mixing: The first-stage compound is added to the internal mixer for hot mixing at a speed of 30 rpm and a temperature of 110°C. After hot mixing for 160 seconds, the compound is discharged and filtered using a filter with a mesh size of 40-80. The filtered compound is left to stand for 20 hours to obtain the second-stage compound.

[0092] (3) Three-stage mixing: Heat stabilizer HS-80, thermal conductivity enhancer TB-S, resin curing agent SL-RA65, adhesive Y, insoluble sulfur HDOT-20, accelerator NS, anti-sulfurization reversion agent WK-901, anti-scorching agent CTP, two-stage compound rubber and other materials are added to the internal mixer for mixing. The mixing speed is 20 rpm, the mixing time is 200 seconds, the mixing temperature is 110℃ and the rubber is discharged. After cooling and standing for 16 hours, the various additives are more evenly dispersed in the rubber to obtain the three-stage compound rubber. The compound rubber is extruded into rubber strips with a width of 70mm and a thickness of 20mm by an extruder for later use.

[0093] (4) The spare film obtained in step (3) is extruded and compounded with 6 polyamide 66 cords using a twin-screw extruder. The extrusion temperature is 80℃ and the extrusion speed is 10 m / min to obtain the final crown strip adhesive strip.

[0094] The performance test results of the adhesive strips for the crown strips of aircraft radial tires prepared in Comparative Examples 6-8 are shown in Table 9.

[0095] Table 9. Performance of the adhesive strips for radial tire crown strips prepared in Comparative Examples 6-8

[0096] project Comparative Example 6 Comparative Example 7 Comparative Example 8 Tensile strength, MPa 21.3 20.9 21.6 Elongation at break, % 372 364 397 300% constant tensile stress, MPa 16.1 15.2 10.7 Tear strength, kN / m 73 81 68 Compression fatigue heat generation, ℃ 33 35 37 Adhesive strength of the adhesive thread, N 157 134 151 Torque curve change rate of sulfur translucency analyzer at 143℃ for 60 minutes -19 -24 -22 Elongation change rate after aging in hot air at 100℃ for 24 hours -28 -30 -28 Mooney viscosity ML1+4 (100℃) 81 83 58

[0097] The crown belt adhesive strips extruded using the preparation methods of Comparative Examples 6-8 exhibited high heat generation, poor adhesion, and significant dimensional changes. The shrinkage rates of the crown belt adhesive strips prepared in Comparative Examples 6-8 at 177℃ for 2 minutes were 3.7%, 4.5%, and 2.3%, respectively. After winding the belt layer using an aviation radial two-stage forming machine, 1030×350R500 aviation radial tires were produced. After vulcanization, the outer dimensions of the finished tires changed significantly, with a smaller outer diameter and narrower cross-sectional width, failing to meet tire design requirements (see Table 10 for details).

[0098] Table 10 shows the outer edge dimensions of the finished tires prepared using the crown strip adhesives prepared in Comparative Examples 6-8.

[0099] Tire size standard Comparative Example 6 Comparative Example 7 Comparative Example 8 Inflatable outer diameter, mm 995±10 979 977 983 Inflatable cross-section width, mm 317±8 307 299 303

[0100] Analysis of Examples 1-3 and Comparative Examples 6-8 shows that conventional mixing methods and adjustments to the mixing temperature during mixing can affect the performance of the final crown strip adhesive and the changes in the outer edge dimensions of the finished tire. Compared with Comparative Examples 6-8, the adhesive lines in the examples have high bonding strength, high tear strength, low heat generation, and moderate Mooney viscosity, resulting in tires with outer edge dimensions that meet standard requirements. In contrast, Comparative Examples 6-8 have low bonding strength, low tear strength, high heat generation, and excessively high or low Mooney viscosity, resulting in tires with smaller outer diameters and cross-sectional widths that fail to meet the required specifications.

[0101] Analysis of Examples 1-3 and Comparative Examples 6-8 shows that conventional mixing methods and adjustments to the mixing temperature during mixing can affect the performance of the final crown strip adhesive and the changes in the outer edge dimensions of the finished tire. Compared with Comparative Examples 6-8, the adhesive lines in the examples have high bonding strength, high tear strength, low heat generation, and moderate Mooney viscosity, resulting in tires with outer edge dimensions that meet standard requirements. In contrast, Comparative Examples 6-8 have low bonding strength, low tear strength, high heat generation, and excessively high or low Mooney viscosity, resulting in tires with smaller outer diameters and cross-sectional widths that fail to meet the required specifications.

[0102] Table 11 Manufacturer's Brand of Raw Materials Used in Examples 1-3 and Comparative Examples 1-8

[0103] raw material factory Domestic natural rubber GCR-2 Rubber Research Institute, Chinese Academy of Tropical Agricultural Sciences Fast-pressed carbon black N550 Jiangxi Black Cat Carbon Black Co., Ltd. Highly dispersible silica ZJ1333 Fujian Sanming Zhengyuan Chemical Co., Ltd. Silica dispersant (FS-78) Qingdao Angji Rubber & Plastic Technology Co., Ltd. Silane coupling agent KH550 Nanjing Shuguang Silane Chemical Co., Ltd. Heat stabilizer HS-80 Dalian Tianbao Chemical Industry Co., Ltd. Thermal conductivity enhancer TB-S Dalian Tianbao Chemical Industry Co., Ltd. Nano zinc oxide Shandong Xingya New Materials Co., Ltd. stearic acid Wilmar Oils & Fats Technology Co., Ltd. p-Phenylenediamine antioxidant 4020 Saint-Austen Chemical Technology Co., Ltd. Ketone amine antioxidants RD Comay Chemical Co., Ltd. Adhesive resin SL3022 Huachi (China) Chemical Co., Ltd. resorcinol Dandong Chaoguan Chemical Industry Co., Ltd. Accelerator H Shandong Runyin Biochemical Co., Ltd. Resin curing agent SL-RA65 Huachi (China) Chemical Co., Ltd. Insoluble sulfur HDOT-20 Weilin New Materials Technology Co., Ltd. sulfenamide accelerator NS Comay Chemical Co., Ltd. Anti-reversion agent WK-901 Wuhan Jiyesheng Chemical Co., Ltd. CTP (Catalyst) Haiteng Additives Co., Ltd.

Claims

1. A method for preparing an adhesive for the crown strip of an aircraft radial tire, characterized in that, The weight ratio of each component of the adhesive raw material is as follows: Natural rubber 100 Reinforcing agent 30-60 Highly dispersible silica 5-15 Silica dispersant 1-3 Silane coupling agent 1-4 Heat stabilizer HS-80 0.5~3 Thermal conductivity enhancer TB-S 0.5~2 Nano zinc oxide 2-5 Stearic acid 0.5-3 p-Phenylenediamine antioxidant 4020 1-4 Ketoamine antioxidants RD 1-4 Adhesive resin SL3022 0.5~3 Adhesive Y 0.5~3 Resin curing agent SL-RA65 0.5~3 Insoluble sulfur HDOT-20 1~4 sulfenamide accelerator NS 0.5-3 Anti-sulfurization reversion agent WK-901 0.5~1 CTP (Chemical Inhibitor) 0.1-0.4 g / L The binder Y is prepared by ball milling resorcinol, accelerator H and silica in a mass ratio of 1:1:1.2-1.6 and drying in an oven at 90-110℃ for 2 hours; the particle size of binder Y is 1-3 nm. The silane coupling agent is silane coupling agent KH550; The preparation method of the adhesive for the crown strip of the aviation radial tire includes the following steps: (1) A stage of mixing Add the required amounts of natural rubber, nano zinc oxide, stearic acid, adhesive resin SL3022, p-phenylenediamine antioxidant 4020, and ketone-amine antioxidant RD to a mixing mill and mix at a speed of 30-50 rpm. After mixing for 140-160 seconds, add the required amounts of reinforcing agent, highly dispersible silica, silane coupling agent KH550, and silica dispersant. Adjust the mixing speed to 70-80 rpm and rapidly raise the mixing temperature to 185-190℃. Simultaneously, lift the top bolt and spray cold water onto the outer wall of the mixing chamber for 5-10 seconds to lower the rubber compound temperature to 130-140℃. Lower the top bolt and restore the speed to 30-50 rpm. Continue mixing for 280-300 seconds, until the mixing temperature reaches 150-160℃. Discharge the rubber compound and allow it to cool and stand for 8-16 hours to obtain a first-stage compound. (2) Two-stage mixing Add the first stage of compound rubber to the internal mixer for hot refining at a speed of 20-30 rpm for 160-200 seconds. When the refining temperature reaches 90-105℃, discharge the rubber and filter it using a filter. Let the filtered rubber stand for 8-24 hours to obtain the second stage of compound rubber. (3) Three-stage mixing Add the required heat stabilizer HS-80, thermal conductivity enhancer TB-S, resin curing agent SL-RA65, adhesive Y, insoluble sulfur HDOT-20, accelerator NS, anti-sulfurization reversion agent WK-901, anti-scorching agent CTP, and two-stage compound into an internal mixer and mix at a speed of 10-25 rpm for 180-220 seconds. Discharge the compound at a temperature of 95-100℃ and allow it to cool and stand for 8-16 hours to obtain three-stage compound. The three-stage compound rubber is extruded into strips with a width of 40-80mm and a thickness of 10-30mm using an extruder to obtain crown strip adhesive film; (4) The crown band adhesive film obtained in step (3) is extruded and compounded with 4-7 polyamide 66 cords using a twin-screw extruder to obtain the final crown band adhesive strip.

2. The method for preparing the adhesive for the crown strip of an aircraft radial tire according to claim 1, characterized in that, The reinforcing agent is one or both of fast-extrusion carbon black N550 and N660.

3. The method for preparing the adhesive for the crown strip of an aircraft radial tire according to claim 1, characterized in that, In step (2), the filter screen mesh size is 40-80 mesh. In step (4), the extrusion temperature of the twin-screw extruder is 75-85℃ and the extrusion speed is 5-15 m / min.

4. An adhesive for the crown strip of an aircraft radial tire prepared by any of the preparation methods described in claims 1-3.