Environmentally friendly pressure-resistant inner tube and preparation method thereof

Abstract

The present invention provides an environment-friendly pressure-resistant inner tube and a preparation method thereof, the preparation method comprising the following steps: (1) weighing raw materials of a masterbatch, specifically comprising the following components in parts by weight: 60-65 parts of butyl rubber, 35-40 parts of modified waste butyl rubber, 6-11 parts of EVA resin, 5-10 parts of chloroprene rubber, 70-75 parts of carbon black, 4-9 parts of modified filler, 6-12 parts of paraffin oil, 3-6 parts of a cross-linking agent, 1-1.5 parts of stearic acid, and 1.6-1.8 parts of sulfur; (2) adding butyl rubber, modified waste butyl rubber, chloroprene rubber, and EVA resin into a closed rubber mixer and kneading for 5-7 minutes; continuing to add carbon black and modified filler under heat preservation conditions and kneading for 2-3 minutes; finally, adding the remaining components and kneading for 5-7 minutes to obtain a mixed rubber, molding the mixed rubber, and vulcanizing it to obtain an environment-friendly pressure-resistant inner tube. The inner tube of the present invention has excellent comprehensive performance.

Description

Technical Field

[0001] The invention belongs to the technical field of tires, and particularly relates to an environmentally friendly pressure-resistant inner tube and a preparation method thereof. Background Art

[0002] An inner tube, commonly known as a tire, is a donut-shaped elastic tube with a tire valve that maintains pressure inside the tire. The valve is used to inflate and maintain a constant pressure inside the inner tube. Inner tubes are typically made of butyl rubber.

[0003] With the rapid development of butyl inner tubes, a large number of scrapped butyl inner tubes are produced each year. Because they cannot be naturally decomposed, many of them are treated as waste and garbage, which not only pollutes the environment but also causes a large waste of resources. Recycling and reusing scrap automobile inner tubes, processing and reproducing them, and realizing the recycling of scrap inner tubes can solve the problem of environmental pollution and maximize resource utilization.

[0004] Currently, the main treatment for discarded butyl inner tubes is desulfurization. However, the waste butyl rubber after desulfurization is still a highly saturated and relatively inert material. When this material is added to fresh rubber, the chemical bonding ability between it and the fresh rubber is not ideal, and the product cannot meet consumer demand.

[0005] Therefore, there is an urgent need for an environmentally friendly pressure-resistant inner tube and a preparation method thereof. Summary of the Invention

[0006] The purpose of the present invention is to provide an environmentally friendly pressure-resistant inner tube and a preparation method thereof.

[0007] In order to achieve the above object, the present invention provides the following technical solutions:

[0008] A method for preparing an environmentally friendly pressure-resistant inner tube, comprising the following steps:

[0009] (1) Weighing the raw materials of the masterbatch, specifically including the following components in parts by weight: 60-65 parts of butyl rubber, 35-40 parts of modified waste butyl rubber, 6-11 parts of EVA resin, 5-10 parts of chloroprene rubber, 70-75 parts of carbon black, 4-9 parts of modified filler, 6-12 parts of paraffin oil, 3-6 parts of crosslinking agent, 1-1.5 parts of stearic acid and 1.6-1.8 parts of sulfur;

[0010] (2) Butyl rubber, modified waste butyl rubber, chloroprene rubber, and EVA resin are added to a closed rubber mixer and kneaded at 120-130° C. for 5-7 minutes; carbon black and modified fillers are continuously added under heat preservation conditions and kneaded for 2-3 minutes; finally, the remaining components are added and kneaded at 110-120° C. for 5-7 minutes to obtain a mixed rubber, which is molded to obtain a tire tube, and the tire tube is vulcanized to obtain an environmentally friendly pressure-resistant inner tube.

[0011] Furthermore, the preparation method of the modified waste butyl rubber comprises the following steps:

[0012] (1) washing the waste butyl rubber, drying it, and crushing it using a crusher to obtain rubber particles of 60-100 mesh;

[0013] (2) mixing 16-20 parts by weight of a softener, 1-3 parts of an activator, and 100 parts by weight of rubber particles, stirring the mixture evenly, placing the mixture into a desulfurization device, desulfurizing the mixture at 200-220° C. for 10-15 minutes, and cooling the mixture to obtain a desulfurized rubber material;

[0014] (3) 100 parts by weight of desulfurized rubber material, 10-13 parts by weight of unsaturated ester containing hydroxyl group and 1-3 parts by weight of benzoyl peroxide are mixed, stirred at 120-130° C. for 2-3 hours, and cooled to room temperature to obtain modified waste butyl rubber.

[0015] Furthermore, the softener is a mixture of rapeseed oil, cottonseed oil and rubber seed oil in a weight ratio of 1: (1.2-1.4): (0.5-0.8).

[0016] Furthermore, the activator is stearic acid.

[0017] Furthermore, the hydroxyl-containing unsaturated ester includes pentaerythritol diacrylate monostearate, polydipentaerythritol pentaacrylate and pentaerythritol triacrylate in a weight ratio of 1:(1.2-1.4):(0.5-0.7).

[0018] Pentaerythritol diacrylate monostearate, CAS: 92092-01-8, was purchased from Shanghai Jizhi Biochemical Technology Co., Ltd.

[0019] Polydipentaerythritol pentaacrylate, CAS: 60506-81-2. Hubei Qiniu Chemical Technology Co., Ltd.

[0020] Pentaerythritol triacrylate, CAS: 3524-68-3.

[0021] Furthermore, the cross-linking agent is selected from one or more of hexamethylene diisocyanate, isophorone diisocyanate, and methylene diphenyl diisocyanate.

[0022] In the prior art, the desulfurization process of waste butyl rubber is to increase the plasticization degree of the waste rubber by destroying its cross-linking network, so as to facilitate better fusion with fresh rubber and other materials. However, the use effect of the waste butyl rubber after desulfurization treatment is not ideal. The present invention uses stearic acid as an activator to make the desulfurization more thorough, and at the same time uses a hydroxyl-containing unsaturated ester to modify the desulfurized rubber material, and mixes it with the remaining components to improve the tensile strength of the environmentally friendly pressure-resistant inner tube. The analysis shows that after the hydroxyl active group is introduced into the desulfurized rubber material by grafting, a cross-linking network can be formed with the cross-linking agent in the system. At the same time, the complex molecular chain of the hydroxyl-containing unsaturated ester can further increase the complexity of the cross-linking network, and through synergistic effect, the tensile strength of the environmentally friendly pressure-resistant inner tube is improved. However, the elongation at break under this condition is not ideal.

[0023] Furthermore, the vulcanization conditions are: vulcanization temperature 170-180° C., vulcanization time 5-8 minutes, and pressure 0.6-0.9 MPa.

[0024] Furthermore, the EVA resin comprises EVA resin No. 1, EVA resin No. 2 and EVA resin No. 3 in a weight ratio of 1: (1.3-1.5): (0.4-0.7); the vinyl acetate content of EVA resin No. 1 is 5 wt%, and the melt flow rate is 1.2 g / 10 min (190° C. / 2.16 kg). DowDuPont, ELVAX TM EVA, model 3120; No. 2 EVA resin has a vinyl acetate content of 8 wt%, a melt flow rate of 3 g / 10 min (190°C / 2.16 kg), DowDuPont, ELVAX TM EVA, model 265. The vinyl acetate content of EVA resin No. 3 is 25wt%, and the melt flow rate is 19g / 10min (190℃ / 2.16kg), DowDuPont, ELVAX TM EVA, model 350.

[0025] The present invention improves the elongation at break of inner tubes by adding EVA resin to the masterbatch. EVA resin, due to its vinyl acetate monomer content, has a certain degree of flexibility. Adding EVA to butyl rubber can enhance the flexibility of the composite material, thereby improving its elongation at break. EVA also has good compatibility with butyl rubber and can be well dispersed in the butyl rubber matrix. This good compatibility helps to more evenly distribute stress within the material when subjected to external forces, reducing stress concentration and thereby improving elongation at break. The tear strength of the inner tube can also be improved.

[0026] Furthermore, the preparation method of the modified filler comprises the following steps: by weight,

[0027] (1) mixing nano-silicon dioxide, nano-calcium carbonate and nano-zinc oxide to obtain a mixed nano-filler;

[0028] (2) uniformly mixing a mixed filler, anhydrous ethanol, and a silane coupling agent KH550 in a weight ratio of 1:(8-10):(0.1-0.2), reacting at 40-45° C. for 3-5 hours, filtering, washing, and vacuum drying to obtain an aminosilane-modified filler;

[0029] (3) Mixing aminosilane modified filler, anhydrous ethanol, glycidyl methacrylate and azobisisobutyronitrile in a weight ratio of 30: (80-90): (2.2-2.5): (0.15-0.2), stirring at 60-65 ° C for 4-6 hours, cooling to room temperature, standing for 25-30 hours, filtering, washing, and drying to obtain a modified filler.

[0030] Furthermore, the weight ratio of nano-silicon dioxide, nano-calcium carbonate and nano-zinc oxide is (0.2-0.4):1:(1.5-1.7).

[0031] Furthermore, the particle size of nano-silicon dioxide is 10-25nm, the average particle size is 20nm, and the specific surface area is 150-200m 2 / g; the particle size of nano calcium carbonate is 40-70nm, the average particle size is 50nm, and the specific surface area is 40-60m 2 / g; the particle size of nano zinc oxide is 20-40nm, the average particle size is 34nm, and the specific surface area is 10-20m 2 / g.

[0032] To improve the thermal tensile deformability of inner tubes, the present invention attempted to add modified fillers, but the results were unsatisfactory. The present invention improves the thermal tensile deformability of inner tubes by modifying the fillers. Analysis shows that by mixing nano-silica, nano-calcium carbonate, and nano-zinc oxide, a composite filler with multiple performance advantages can be obtained. Glycidyl methacrylate can react with active groups on the filler surface, enhancing the interaction between the filler and the rubber matrix. The modified filler can improve the dispersibility of the filler, making it more evenly distributed in the butyl rubber system, thereby improving the thermal tensile deformability of the material.

[0033] When a car is used in different seasons and regions, the ambient temperature can vary greatly. Especially in summer or tropical regions, the high external ambient temperature, coupled with the heat generated during vehicle operation, can cause the temperature inside the inner tube to rise. High temperatures can accelerate the aging process of the rubber material, leading to performance degradation. Under high temperature conditions, the inner tube needs to maintain its mechanical properties; otherwise, the inner tube may become fragile and malfunction. The use of EVA resin with specific parameters and filler with specific parameters in the system of the present invention can improve the heat-resistant air aging performance of the inner tube. This is because the EVA resin and filler with specific parameters form a stable composite network structure in the butyl rubber matrix. This structure can maintain good stability at high temperatures and is not prone to degradation or aging.

[0034] The present invention also provides an environmentally friendly pressure-resistant inner tube prepared by the preparation method.

[0035] Compared with the prior art, the advantages and beneficial effects of the present invention are:

[0036] 1. The present invention uses stearic acid as an activator to make desulfurization more thorough, and uses a hydroxyl-containing unsaturated ester to modify the desulfurized rubber material, thereby improving the tensile strength of the environmentally friendly pressure-resistant inner tube.

[0037] 2. The present invention can improve the elongation at break of the inner tube by adding EVA resin to the masterbatch, and can also improve the tear strength of the inner tube.

[0038] 3. The present invention can improve the thermal tensile deformation of the inner tube by modifying the filler with a specific ratio.

[0039] 4. The use of EVA resin with specific parameters and filler with specific parameters in the system of the present invention can improve the hot air aging resistance of the inner tube. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 This is a physical picture of the environmentally friendly pressure-resistant inner tube prepared in Example 1. DETAILED DESCRIPTION

[0041] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0042] The raw materials used in the following examples of the present invention are all commercially available commodities:

[0043] Neoprene, brand: Covestro (Lanxess), model Neoprene 320-1.

[0044] Paraffin oil, Shandong Mingyue Chemical Co., Ltd., model MY white oil.

[0045] Butyl rubber, brand: Jingboju, grade IIR1953.

[0046] Waste butyl rubber, waste butyl rubber automobile inner tube.

[0047] Rapeseed oil, rapeseed oil, commercially available.

[0048] Example 1

[0049] like Figure 1 As shown, this embodiment provides an environmentally friendly pressure-resistant inner tube, and its preparation method includes the following steps: by weight,

[0050] (1) Weigh the raw materials of the masterbatch, specifically including the following components in parts by weight: 62 parts of butyl rubber, 38 parts of modified waste butyl rubber, 9 parts of EVA resin, 7 parts of chloroprene rubber, 72 parts of carbon black, 7 parts of modified filler, 9 parts of paraffin oil, 5 parts of crosslinking agent hexamethylene diisocyanate, 1.2 parts of stearic acid, and 1.7 parts of sulfur;

[0051] (2) Butyl rubber, modified waste butyl rubber, chloroprene rubber, and EVA resin are added to a closed rubber mixer and kneaded at 125° C. for 6 minutes; carbon black and modified fillers are continuously added under heat preservation conditions and kneaded for 3 minutes; finally, the remaining components are added and kneaded at 115° C. for 6 minutes to obtain a kneaded rubber, which is molded to obtain a tire tube, which is vulcanized under the following vulcanization conditions: a vulcanization temperature of 175° C., a vulcanization time of 7 minutes, and a pressure of 0.7 MPa to obtain an environmentally friendly pressure-resistant inner tube.

[0052] The preparation method of the modified waste butyl rubber comprises the following steps:

[0053] (1) washing the waste butyl rubber, drying it, and crushing it using a crusher to obtain rubber particles of 60-100 mesh;

[0054] (2) 18 parts by weight of a softener, 2 parts of an activator, and 100 parts by weight of rubber particles were mixed, stirred uniformly, loaded into a desulfurization device, desulfurized at 210° C. for 12 minutes, and cooled to obtain a desulfurized rubber material; the softener was a mixture of rapeseed oil, cottonseed oil, and rubber seed oil in a weight ratio of 1:1.3:0.7. The activator was stearic acid.

[0055] (3) 100 parts by weight of desulfurized rubber material, 12 parts by weight of hydroxyl-containing unsaturated ester and 2 parts by weight of benzoyl peroxide were mixed, wherein the hydroxyl-containing unsaturated ester included pentaerythritol diacrylate monostearate, polydipentaerythritol pentaacrylate and pentaerythritol triacrylate in a weight ratio of 1:1.3:0.6, and the mixture was stirred at 125°C for 2.5 hours and cooled to room temperature to obtain modified waste butyl rubber.

[0056] The EVA resin comprises EVA resin No. 1, EVA resin No. 2 and EVA resin No. 3 in a weight ratio of 1:1.4:0.6; the vinyl acetate content of EVA resin No. 1 is 5 wt %, and the melt flow rate is 1.2 g / 10 min (190° C. / 2.16 kg). DowDuPont, ELVAX TM EVA, model 3120; No. 2 EVA resin has a vinyl acetate content of 8 wt%, a melt flow rate of 3 g / 10 min (190°C / 2.16 kg), DowDuPont, ELVAX TM EVA, model 265. The vinyl acetate content of EVA resin No. 3 is 25wt%, and the melt flow rate is 19g / 10min (190℃ / 2.16kg), DowDuPont, ELVAX TM EVA, model 350.

[0057] The preparation method of the modified filler comprises the following steps: by weight,

[0058] (1) Nano-silicon dioxide, nano-calcium carbonate and nano-zinc oxide are mixed in a weight ratio of 0.3:1:1.6 to obtain a mixed nano-filler; the particle size of the nano-silicon dioxide is 10-25 nm, the average particle size is 20 nm, and the specific surface area is 150-200 m 2 / g; the particle size of nano calcium carbonate is 40-70nm, the average particle size is 50nm, and the specific surface area is 40-60m 2 / g; the particle size of nano zinc oxide is 20-40nm, the average particle size is 34nm, and the specific surface area is 10-20m 2 / g.

[0059] (2) Mixing the mixed filler, anhydrous ethanol and silane coupling agent KH550 in a weight ratio of 1:9:0.15, reacting at 42°C for 4 hours, filtering, washing and vacuum drying to obtain an aminosilane-modified filler;

[0060] (3) Aminosilane modified filler, anhydrous ethanol, glycidyl methacrylate and azobisisobutyronitrile in a weight ratio of 30:85:2.3:0.17 were mixed, stirred at 62°C for 5 hours, cooled to room temperature, allowed to stand for 28 hours, filtered, washed and dried to obtain a modified filler.

[0061] Example 2

[0062] This embodiment provides an environmentally friendly pressure-resistant inner tube, and a preparation method thereof comprises the following steps: by weight,

[0063] (1) Weigh the raw materials of the masterbatch, specifically including the following components in parts by weight: 60 parts of butyl rubber, 40 parts of modified waste butyl rubber, 6 parts of EVA resin, 10 parts of chloroprene rubber, 70 parts of carbon black, 9 parts of modified filler, 6 parts of paraffin oil, 6 parts of crosslinking agent hexamethylene diisocyanate, 1.5 parts of stearic acid, and 1.6 parts of sulfur;

[0064] (2) Butyl rubber, modified waste butyl rubber, chloroprene rubber, and EVA resin are added to a closed rubber mixer and kneaded at 130° C. for 5 minutes; carbon black and modified fillers are continuously added under heat preservation conditions and kneaded for 3 minutes; finally, the remaining components are added and kneaded at 110° C. for 7 minutes to obtain a kneaded rubber, which is then molded to obtain a tire tube, which is then vulcanized under the following vulcanization conditions: a vulcanization temperature of 170° C., a vulcanization time of 8 minutes, and a pressure of 0.6 MPa to obtain an environmentally friendly pressure-resistant inner tube.

[0065] The preparation method of the modified waste butyl rubber comprises the following steps: by parts by weight,

[0066] (1) washing the waste butyl rubber, drying it, and crushing it using a crusher to obtain rubber particles of 60-100 mesh;

[0067] (2) 16 parts by weight of a softener, 3 parts of an activator, and 100 parts by weight of rubber particles were mixed, stirred uniformly, loaded into a desulfurization device, desulfurized at 220° C. for 10 minutes, and cooled to obtain a desulfurized rubber material; the softener was a mixture of rapeseed oil, cottonseed oil, and rubber seed oil in a weight ratio of 1:1.2:0.8. The activator was stearic acid.

[0068] (3) 100 parts by weight of desulfurized rubber material, 10 parts by weight of hydroxyl-containing unsaturated ester and 3 parts by weight of benzoyl peroxide were mixed, wherein the hydroxyl-containing unsaturated ester included pentaerythritol diacrylate monostearate, polydipentaerythritol pentaacrylate and pentaerythritol triacrylate in a weight ratio of 1:1.4:0.5, stirred at 120°C for 3 hours, and cooled to room temperature to obtain modified waste butyl rubber.

[0069] The EVA resin comprises EVA resin No. 1, EVA resin No. 2 and EVA resin No. 3 in a weight ratio of 1:1.3:0.7; the vinyl acetate content of EVA resin No. 1 is 5 wt %, and the melt flow rate is 1.2 g / 10 min (190° C. / 2.16 kg). DowDuPont, ELVAX TMEVA, model 3120; No. 2 EVA resin has a vinyl acetate content of 8 wt%, a melt flow rate of 3 g / 10 min (190°C / 2.16 kg), DowDuPont, ELVAX TM EVA, model 265. The vinyl acetate content of EVA resin No. 3 is 25wt%, and the melt flow rate is 19g / 10min (190℃ / 2.16kg), DowDuPont, ELVAX TM EVA, model 350.

[0070] The preparation method of the modified filler comprises the following steps: by weight,

[0071] (1) Nano-silicon dioxide, nano-calcium carbonate and nano-zinc oxide are mixed in a weight ratio of 0.2:1:1.7 to obtain a mixed nano-filler; the particle size of the nano-silicon dioxide is 10-25 nm, the average particle size is 20 nm, and the specific surface area is 150-200 m 2 / g; the particle size of nano calcium carbonate is 40-70nm, the average particle size is 50nm, and the specific surface area is 40-60m 2 / g; the particle size of nano zinc oxide is 20-40nm, the average particle size is 34nm, and the specific surface area is 10-20m 2 / g.

[0072] (2) Mixing the mixed filler, anhydrous ethanol and silane coupling agent KH550 in a weight ratio of 1:10:0.2, reacting at 45°C for 3 hours, filtering, washing and vacuum drying to obtain an aminosilane-modified filler;

[0073] (3) Aminosilane modified filler, anhydrous ethanol, glycidyl methacrylate and azobisisobutyronitrile in a weight ratio of 30:90:2.5:0.2 were mixed, stirred at 65°C for 6 hours, cooled to room temperature, allowed to stand for 30 hours, filtered, washed and dried to obtain a modified filler.

[0074] Comparative Example 1

[0075] The difference between this comparative example and Example 1 is that the raw materials of the masterbatch body are weighed, specifically including the following components in parts by weight: 70 parts of butyl rubber, 30 parts of modified waste butyl rubber, 2 parts of EVA resin, 14 parts of chloroprene rubber, 72 parts of carbon black, 7 parts of modified filler, 9 parts of paraffin oil, 5 parts of cross-linking agent hexamethylene diisocyanate, 1.2 parts of stearic acid and 1.7 parts of sulfur.

[0076] Comparative Example 2

[0077] The difference between this comparative example and Example 1 is that the modified waste butyl rubber is only subjected to vulcanization treatment.

[0078] The preparation method of the modified waste butyl rubber comprises the following steps:

[0079] (1) washing the waste butyl rubber, drying it, and crushing it using a crusher to obtain rubber particles of 60-100 mesh;

[0080] (2) 18 parts by weight of a softener, 2 parts of an activator and 100 parts by weight of rubber particles are mixed, wherein the softener is a mixture of rapeseed oil, cottonseed oil and rubber seed oil in a weight ratio of 1:1.3:0.7, and the activator is stearic acid. After stirring evenly, the mixture is loaded into a desulfurization device, desulfurized at 210°C for 12 minutes, and cooled to obtain modified waste butyl rubber.

[0081] Comparative Example 3

[0082] The difference between this comparative example and Example 1 is that the EVA resin comprises EVA resin No. 1, EVA resin No. 2, and EVA resin No. 3 in a weight ratio of 1:1:1; the vinyl acetate content of EVA resin No. 1 is 5 wt %, and the melt flow rate is 1.2 g / 10 min (190° C. / 2.16 kg). DowDuPont, ELVAX TM EVA, model 3120; No. 2 EVA resin has a vinyl acetate content of 8 wt%, a melt flow rate of 3 g / 10 min (190°C / 2.16 kg), DowDuPont, ELVAX TM EVA, model 265. The vinyl acetate content of EVA resin No. 3 is 25wt%, and the melt flow rate is 19g / 10min (190℃ / 2.16kg), DowDuPont, ELVAX TM EVA, model 350.

[0083] Comparative Example 4

[0084] The difference between this comparative example and Example 1 is that the vinyl acetate content of EVA resin No. 1 is 9.5 wt %, the melt flow rate is 0.8 g / 10 min (190° C. / 2.16 kg), DowDuPont, ELVAX TM EVA, model 770; No. 2 EVA resin has a vinyl acetate content of 12 wt%, a melt flow rate of 0.35 g / 10 min (190°C / 2.16 kg), DowDuPont, ELVAX TM EVA, model 670. The vinyl acetate content of EVA resin No. 3 is 40wt%, and the melt flow rate is 3g / 10min (190℃ / 2.16kg). DowDuPont, ELVAX TM EVA, model 40L-03.

[0085] Comparative Example 5

[0086] The difference between this comparative example and Example 1 is that nano-silicon dioxide, nano-calcium carbonate and nano-zinc oxide are mixed in a weight ratio of 1:1:1.

[0087] Comparative Example 6

[0088] The difference between this comparative example and Example 1 is that the particle size of nano calcium carbonate is 150-200nm, the average particle size is 165nm, and the specific surface area is 10-20m 2 / g; the particle size of nano zinc oxide is 70-100nm, the average particle size is 85nm, and the specific surface area is 5-10m 2 / g; the particle size of nano-silicon dioxide is 45-60nm, the average particle size is 55nm, and the specific surface area is 100-140m 2 / g.

[0089] Comparative Example 7

[0090] The difference between this comparative example and Example 1 is that the preparation method of the modified filler comprises the following steps: by weight,

[0091] (1) Nano-silicon dioxide, nano-calcium carbonate and nano-zinc oxide are mixed in a weight ratio of 0.3:1:1.6 to obtain a mixed nano-filler; the particle size of the nano-silicon dioxide is 10-25 nm, the average particle size is 20 nm, and the specific surface area is 150-200 m 2 / g; the particle size of nano calcium carbonate is 40-70nm, the average particle size is 50nm, and the specific surface area is 40-60m 2 / g; the particle size of nano zinc oxide is 20-40nm, the average particle size is 34nm, and the specific surface area is 10-20m 2 / g.

[0092] (2) The mixed filler, anhydrous ethanol and silane coupling agent KH550 in a weight ratio of 1:9:0.15 were mixed evenly, reacted at 42°C for 4 hours, filtered, washed and vacuum dried to obtain a modified filler.

[0093] Performance Testing

[0094] The environmentally friendly pressure-resistant inner tubes prepared in Examples 1-2 and Comparative Examples 1-7 were subjected to performance tests.

[0095] A GT-AT-3000 universal tensile testing machine manufactured by Taiwan High Speed Rail was used to test tensile stress-strain properties according to GB / T528-2009, tear strength according to GB / T529-2008, and resistance to hot air aging (100°C x 72h) according to GB / T3512-2001. Tensile strength retention was calculated as follows: tensile strength after aging / tensile strength before aging x 100%; elongation at break retention = elongation at break after aging / elongation at break before aging x 100%. Hot tensile deformation was measured according to GB / T7036.1-2009.

[0096] Table 1 Performance test results

[0097]

[0098] From the above performance test results, it can be seen that the environmentally friendly pressure-resistant inner tubes of Examples 1-2 have excellent comprehensive performance, especially the comprehensive performance of Example 1 is the most outstanding, which is mainly due to the synergistic effect of multiple components.

[0099] However, the comparative examples were significantly worse than the examples in terms of corresponding performance tests because they did not adopt the necessary technical solutions. In comparative example 1, the composition of the raw materials of the masterbatch was changed, and it can be seen that the comprehensive effects of the inner tubes were reduced to varying degrees, proving that the scheme of compounding specific components has an important influence on the performance of the inner tubes. In comparative example 2, the modified waste butyl rubber was only vulcanized, resulting in a decrease in tensile strength. In comparative example 3, the composition ratio of the EVA resin was different, resulting in a decrease in elongation at break and tear strength. In comparative example 4, the parameters of EVA resin No. 1, EVA resin No. 2, and EVA resin No. 3 were different, resulting in a decrease in heat-resistant air aging performance. In comparative example 5, the ratios of nano-silicon dioxide, nano-calcium carbonate, and nano-zinc oxide were different, resulting in a decrease in heat-resistant air aging performance. In comparative example 6, the parameters of the filler were different, resulting in a decrease in heat-resistant air aging performance. In comparative example 7, the modification method of the filler was different, resulting in a decrease in heat-resistant air aging performance. The above experimental results further demonstrate the importance of the technical solutions defined in the present invention for its technical effects.

[0100] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A method for preparing an environmentally friendly pressure-resistant inner tube, characterized in that: The method comprises the following steps: by weight, (1) Weigh the raw materials of the masterbatch, which specifically include the following components: 60-65 parts of butyl rubber, 35-40 parts of modified waste butyl rubber, 6-11 parts of EVA resin, 5-10 parts of chloroprene rubber, 70-75 parts of carbon black, 4-9 parts of modified filler, 6-12 parts of paraffin oil, 3-6 parts of crosslinking agent, 1-1.5 parts of stearic acid and 1.6-1.8 parts of sulfur; (2) Add butyl rubber, modified waste butyl rubber, chloroprene rubber, and EVA resin into a closed rubber mixer and mix them at 120-130°C for 5-7 minutes; continue to add carbon black and modified filler under heat preservation conditions and mix them for 2-3 minutes; finally, add the remaining components and mix them at 110-120°C for 5-7 minutes to obtain a mixed rubber, shape the mixed rubber to obtain a tire tube, and vulcanize the tire tube to obtain an environmentally friendly pressure-resistant inner tube; The preparation method of modified waste butyl rubber comprises: (1) Wash the waste butyl rubber, dry it, and crush it using a crusher to obtain rubber particles of 60-100 mesh; (2) Mix 16-20 parts of softener, 1-3 parts of activator and 100 parts of rubber particles, stir evenly, put into a desulfurization device, desulfurize at 200-220°C for 10-15 minutes, cool, and obtain desulfurized rubber material; (3) Mix 100 parts of desulfurized rubber material, 10-13 parts of hydroxyl-containing unsaturated ester and 1-3 parts of benzoyl peroxide, stir and react at 120-130°C for 2-3 hours, and cool to room temperature to obtain modified waste butyl rubber; The hydroxyl-containing unsaturated ester comprises pentaerythritol diacrylate monostearate, polydipentaerythritol pentaacrylate and pentaerythritol triacrylate in a weight ratio of 1: (1.2-1.4): (0.5-0.7); The cross-linking agent is selected from one or more of hexamethylene diisocyanate, isophorone diisocyanate, and methylene diphenyl diisocyanate; The EVA resin includes EVA resin No. 1, EVA resin No. 2 and EVA resin No. 3 in a weight ratio of 1: (1.3-1.5): (0.4-0.7); the vinyl acetate content of EVA resin No. 1 is 5wt%, and the melt flow rate at 190℃ / 2.16kg is 1.2g / 10min; the vinyl acetate content of EVA resin No. 2 is 8wt%, and the melt flow rate at 190℃ / 2.16kg is 3g / 10min; the vinyl acetate content of EVA resin No. 3 is 25wt%, and the melt flow rate at 190℃ / 2.16kg is 19g / 10min.

2. The method for preparing an environmentally friendly pressure-resistant inner tube according to claim 1, characterized in that: The softener is a mixture of rapeseed oil, cottonseed oil and rubber seed oil in a weight ratio of 1: (1.2-1.4): (0.5-0.8).

3. The method for preparing an environmentally friendly pressure-resistant inner tube according to claim 1, characterized in that: The activator is stearic acid.

4. The method for preparing an environmentally friendly pressure-resistant inner tube according to claim 1, characterized in that: The preparation method of the modified filler comprises the following steps: by weight, (1) Mixing nano-silicon dioxide, nano-calcium carbonate and nano-zinc oxide to obtain a mixed nano-filler; (2) Mix the mixed filler, anhydrous ethanol and silane coupling agent KH550 in a weight ratio of 1: (8-10): (0.1-0.2) evenly, react at 40-45 ° C for 3-5 hours, filter, wash and vacuum dry to obtain aminosilane modified filler; (3) Mix aminosilane modified filler, anhydrous ethanol, glycidyl methacrylate and azobisisobutyronitrile in a weight ratio of 30: (80-90): (2.2-2.5): (0.15-0.2), stir and react at 60-65 ° C for 4-6 hours, cool to room temperature, stand for 25-30 hours, filter, wash and dry to obtain a modified filler.

5. The method for preparing an environmentally friendly pressure-resistant inner tube according to claim 4, characterized in that: The weight ratio of nano silicon dioxide, nano calcium carbonate and nano zinc oxide is (0.2-0.4):1:(1.5-1.7).

6. The method for preparing an environmentally friendly pressure-resistant inner tube according to claim 5, characterized in that: The particle size of nano-silicon dioxide is 10-25nm, the average particle size is 20nm, and the specific surface area is 150-200m 2 / g; the particle size of nano calcium carbonate is 40-70nm, the average particle size is 50nm, and the specific surface area is 40-60m 2 / g; the particle size of nano zinc oxide is 20-40nm, the average particle size is 34nm, and the specific surface area is 10-20m 2 / g.

7. An environmentally friendly pressure-resistant inner tube prepared according to the preparation method according to any one of claims 1 to 6.

Images