A tear-resistant resin, its preparation and use

Abstract

The application discloses an anti-tearing resin and a preparation method and application thereof, and relates to the technical field of rubber additives. The anti-tearing resin comprises petroleum resin, modified rosin-based polyester, terpene resin and an initiator. The modified rosin-based polyester is prepared by the following steps: natural rosin is reacted with maleic anhydride to generate maleopimaric anhydride, the maleopimaric anhydride is reacted with polyhydric alcohol to form an ultrabranched structure, and the ultrabranched structure is modified by glycidyl methacrylate and long-chain fatty acid chloride containing C12-C18. According to the scheme, the polarity of the prepared anti-tearing resin can be effectively reduced, the dispersibility and the compatibility of the anti-tearing resin in non-polar rubber are improved, the anti-tearing improvement effect of the anti-tearing resin on the non-polar rubber is improved, and the dynamic working condition requirement of high-end rubber products can be met.

Description

Technical Field

[0001] This invention relates to the technical field of rubber additives, and in particular to a tear-resistant resin, its preparation method, and its application. Background Technology

[0002] In rubber products, especially large rubber products such as tires and conveyor belts that are subjected to dynamic stress, their service life and safety performance are largely limited by the tear resistance and cut resistance of the materials. To improve performance, tear-resistant resins are usually added as modifying agents to non-polar rubber formulations. Currently, tear-resistant resins are widely prepared in industry by copolymerizing C5 and C9 petroleum resins with natural rosin. These copolymers are mainly produced by grafting the abietic acid structure of rosin onto the main chain of petroleum resin and introducing branched side chains, thereby improving the energy dissipation capacity of the non-polar rubber matrix under tear stress. A mature industrial production system has been formed, and it is widely used in non-polar rubber composite systems such as natural rubber, styrene-butadiene rubber, or cis-butadiene rubber.

[0003] However, existing technologies still have some problems in practical applications. On the one hand, natural rosin contains highly polar carboxyl groups, while the non-polar rubber matrix has low polarity, resulting in poor thermodynamic compatibility between the two. This makes it difficult to achieve nanoscale uniform dispersion of the tear-resistant resin during rubber compounding, and it is prone to migration and precipitation during storage and service, causing blooming. This not only affects the appearance of rubber products but also reduces their overall performance, threatening the long-term safety of products such as tires. On the other hand, most existing copolymer modification systems use rosin monomolecule grafting, which results in limited steric hindrance in the constructed branches, making it difficult to meet the tear and cut resistance requirements of high-end all-steel radial tires under high-speed, heavy-load, and stony road conditions.

[0004] To address the aforementioned issues, existing technologies have attempted to improve the situation through methods such as rosin hydrogenation, maleic anhydride grafting, or compounding with epoxidized soybean oil. However, these technologies are either costly and complex, or they introduce new polar groups, further exacerbating the polarity difference with the non-polar rubber matrix. Alternatively, they may only initially alleviate surface blooming and offer only a minor improvement in the tear resistance of non-polar rubber, failing to meet the demands of specific operating conditions. Therefore, optimizing the resin's branched topology while reducing its polarity to achieve a synergistic improvement in compatibility and tear resistance is of significant practical importance for promoting the development of the rubber products industry. Summary of the Invention

[0005] In order to further improve the compatibility and tear resistance of tear-resistant resins, and overcome the problems of poor compatibility with non-polar rubber matrices and easy blooming of finished products caused by the high polarity of existing tear-resistant resins, so as to meet the dynamic working conditions requirements of high-end rubber products, this application provides a tear-resistant resin, its preparation method and application.

[0006] Firstly, the tear-resistant resin provided in this application adopts the following technical solution: A tear-resistant resin, comprising the following raw materials in parts by weight: Petroleum resin: 50-65 parts; Modified rosin-based polyester: 30-40 parts; Terpene resin: 3-10 parts; Initiator: 0.5-2 parts; The modified rosin-based polyester is prepared by reacting natural rosin with maleic anhydride to generate maleic pimecrolic anhydride, then reacting the maleic pimecrolic anhydride with a polyol to form a hyperbranched structure, and then modifying it with glycidyl methacrylate and long-chain fatty acyl chloride containing C12-C18.

[0007] By adopting the above technical solution, the polarity of the tear-resistant resin can be effectively reduced, thereby improving its dispersibility and compatibility in non-polar rubbers. Combined with the hyperbranched structure, this enhances its tear resistance improvement effect on non-polar rubbers. Compared to traditional petroleum-rosin copolymer tear-resistant resins or petroleum-rosin polyol ester copolymer tear-resistant resins, the resulting tear-resistant resin not only significantly improves the tear strength of rubber but also appropriately increases the mechanical modulus such as tensile stress. Simultaneously, it effectively suppresses blooming, thus meeting the comprehensive requirements of high-end tire products for tear resistance, cut resistance, and long-term service stability under dynamic operating conditions.

[0008] Optionally, the polyol includes one or more combinations of ethylene glycol, 1,3-propanediol, glycerol, trimethylolpropane and pentaerythritol, and the molar ratio of the active carboxyl equivalent of the maleic anhydride to the molar amount of the hydroxyl group of the polyol is 1:(1.2-1.4).

[0009] By adopting the above technical solution, controlling the molar ratio of the active carboxyl equivalent of maleic anhydride to the hydroxyl group of the polyol to be 1:(1.2-1.4) enables the formation of a stable hyperbranched structure after the branching polycondensation reaction, while retaining sufficient terminal hydroxyl groups to facilitate subsequent end-capping modification with glycidyl methacrylate and long-chain fatty acyl chloride. Simultaneously, by optimizing the composition and ratio of the polyol, the branching rate of the rosin-based polyester intermediate can be appropriately adjusted, thereby reducing the problem of excessively high branching rate or steric hindrance affecting subsequent end-capping modification. This also prevents the problem of slight blooming of the rubber caused by partially uncapped components leading to high polarity, thus enabling the tear-resistant resin to achieve both high tear resistance and excellent anti-blooming properties.

[0010] Optionally, the long-chain fatty acyl chloride is specifically selected from long-chain fatty acyl chlorides containing C14-C16.

[0011] By adopting the above technical solution and using long-chain fatty acyl chlorides containing C14-C16 for end-capping modification, a non-polar alkyl protective layer of moderate thickness can be formed around the modified rosin-based polyester. This effectively reduces the polarity of the modified rosin-based polyester and improves the compatibility between the tear-resistant resin and the non-polar rubber. Simultaneously, the long side chains impart good physical entanglement ability to the tear-resistant resin, which is beneficial for achieving optimal dispersion and tear-resistant modification effects in the rubber. Furthermore, the heat aging resistance and anti-blooming properties are also superior. Compared to insufficient shielding due to excessively short C12 carbon chains, or the aggravated plasticizing effect and performance decline caused by excessively long C18 carbon chains, the preferred C14-C16 range is conducive to achieving the optimal balance between tear strength, mechanical modulus, and long-term service stability.

[0012] Optionally, the preparation method of the modified rosin-based polyester includes the following steps: A1. Add natural rosin to the reaction vessel, heat it under an inert atmosphere to melt and soften it, add maleic anhydride and acetic acid in batches while stirring, heat to 160-175℃ and keep it at the temperature under reflux for 2-4 hours after the addition is complete, cool to 100-120℃, add acetic acid and stir to mix, cool to crystallize, filter under reduced pressure, wash, and obtain maleic anhydride; A2. Add the maleic anhydride, polyol and catalyst I obtained in A1 to the reactor, heat to 175-190℃ under an inert atmosphere and keep the reaction at this temperature for 1-2 hours, heat to 200-220℃ and control the vacuum degree to 1-100kPa, and continue to keep the reaction at this temperature for 4-6 hours. After the reaction is completed, cool to obtain a rosin-based polyester intermediate containing a hyperbranched structure. A3. The rosin-based polyester intermediate obtained in A2, along with the glycidyl methacrylate, catalyst II, polymerization inhibitor, and solvent I, are added to a reaction vessel. The reaction is carried out at 120-140°C for 4-6 hours under a vacuum of 1-100 kPa. Then, the temperature is lowered to 35-50°C, and the long-chain fatty acyl chloride and acid-binding agent are added. The reaction is continued for 1-2 hours. After the reaction is completed, the mixture is cooled, allowed to stand to separate the organic layer, and then distilled under reduced pressure to obtain the modified rosin-based polyester.

[0013] By adopting the above technical solution, maleic anhydride is first synthesized from natural rosin via a Diels-Alder addition reaction. Then, it is esterified and polycondensed with a polyol to form a hyperbranched structure. Finally, it is end-capped with bifunctionalized glycidyl methacrylate and long-chain fatty acyl chloride. This process ensures that each step of the reaction is fully and controllably carried out, guaranteeing the complete construction of the hyperbranched structure and the precise introduction of peripheral functional groups. The resulting modified rosin-based polyester has polymerizable double bonds, a nonpolar long-chain alkyl shell, and a rigid hyperbranched core. This facilitates the stable bonding between the modified rosin-based polyester and petroleum resin, and enables the tear-resistant resin to play an efficient and stable tear-resistant reinforcement and stiffening role in nonpolar rubber.

[0014] Optionally, in A3, the amount of glycidyl methacrylate added is 2-3.5% of the mass of the rosin-based polyester intermediate, and the amount of long-chain fatty acyl chloride added is 12-16% of the mass of the rosin-based polyester intermediate.

[0015] By adopting the above technical solution, the addition amount of glycidyl methacrylate is controlled to 2-3.5% of the mass of the rosin-based polyester intermediate, and the addition amount of long-chain fatty acyl chloride is controlled to 12-16% of the mass of the rosin-based polyester intermediate. Maintaining an excess of long-chain fatty acyl chloride is beneficial for introducing an appropriate amount of polymerizable double bonds while ensuring that the secondary hydroxyl groups generated from the ring-opening of glycidyl methacrylate and the unreacted terminal hydroxyl groups of the intermediate are fully capped by the long-chain fatty acyl chloride. An appropriate amount of glycidyl methacrylate helps to appropriately improve the modification effect of the tear-resistant resin and can moderately increase the mechanical modulus of the subsequently modified rubber. The excess of long-chain fatty acyl chloride can passivate the residual terminal hydroxyl groups, reduce the polarity of the modified rosin-based polyester, and thus improve the compatibility of the tear-resistant resin with non-polar rubber, which is beneficial for maintaining good anti-blooming properties.

[0016] Optionally, in A2, catalyst I is stannous oxalate; in A3, catalyst II is stannous octoate, the polymerization inhibitor is p-hydroxyanisole, and the acid-binding agent is triethylamine.

[0017] By adopting the above technical solution, it is beneficial to carry out each step of the reaction efficiently and controllably. While preventing the thermal polymerization of methacrylic acid double bonds during the reaction, it ensures the integrity and functionality of the product structure, thereby facilitating the acquisition of modified rosin-based polyester with stable performance and good reproducibility.

[0018] Optionally, the petroleum resin is one of C5 petroleum resin, or a combination of C5 petroleum resin and C9 petroleum resin.

[0019] By adopting the above technical solution, C5 petroleum resin or C5 / C9 combined petroleum resin is selected as the matrix, which can undergo free radical polymerization with modified rosin-based polyester and terpene resin under initiator conditions and form a stable chemical grafting network. This ensures good compatibility between the tear-resistant resin and the non-polar rubber matrix, which is conducive to the overall uniform dispersion of the tear-resistant resin and further enhances the tear-resistant reinforcement effect brought by its hyperbranched structure.

[0020] Optionally, the initiator is one of azobisisobutyronitrile or benzoyl peroxide.

[0021] By adopting the above technical solution, it is beneficial to initiate the free radical grafting reaction between petroleum resin, terpene resin and modified rosin-based polyester at a suitable temperature, so that stable chemical bonds are formed between the components, thereby ensuring that the obtained tear-resistant resin maintains long-term and stable tear resistance and reinforcement effects in rubber products.

[0022] Secondly, the method for preparing an anti-tear resin provided in this application adopts the following technical solution: A method for preparing a tear-resistant resin includes the following steps: By weight, petroleum resin is heated to 120-150℃ to fully melt and soften it. Modified rosin-based polyester and terpene resin are added. After they are completely melted, softened and mixed, an initiator is added. The mixture is heated to 160-180℃ and stirred for 2-4 hours. After the reaction is completed, the mixture is distilled under reduced pressure to obtain the tear-resistant resin.

[0023] By adopting the above technical solution, it is beneficial for the components to be fully integrated and form a structurally stable tear-resistant resin. At the same time, the process is simple and the conditions are controllable, which is conducive to realizing industrial mass production and ensuring that the tear-resistant resin can stably reproduce the comprehensive properties such as tear resistance, stiffening and anti-blooming in non-polar rubber.

[0024] Thirdly, the application of the tear-resistant resin provided in this application adopts the following technical solution: An application of a tear-resistant resin as an additive to improve the tear resistance of non-polar rubber.

[0025] In summary, the technical solution of this application has at least one of the following beneficial effects: 1. By modifying natural rosin with maleic anhydride and polyol to form a hyperbranched structure, and then combining it with glycidyl methacrylate and long-chain fatty acyl chloride for end-capping modification, the resulting modified rosin-based polyester is reacted with petroleum resin and terpene resin through an initiator to form a tear-resistant resin. This effectively reduces the polarity of the tear-resistant resin, which is beneficial to improving its dispersibility and compatibility in non-polar rubbers, and enhances its tear resistance improvement effect on non-polar rubbers.

[0026] 2. By optimizing the composition and ratio of polyols, the branching rate of rosin-based polyester intermediates can be appropriately adjusted, thereby alleviating the problem of limited end-capping due to excessive branching rate or excessive steric hindrance. This helps prevent the problem of slight blooming of modified rubber caused by high polarity due to some uncapped parts.

[0027] 3. By controlling the addition amount of glycidyl methacrylate to 2-3.5% of the mass of rosin-based polyester intermediate and the addition amount of long-chain fatty acyl chloride to 12-16% of the mass of rosin-based polyester intermediate, the long-chain fatty acyl chloride is kept in excess. This is beneficial to ensure that the secondary hydroxyl groups generated by the ring opening of glycidyl methacrylate and the terminal hydroxyl groups of the intermediate that have not been fully reacted can be fully capped by the long-chain fatty acyl chloride while introducing an appropriate amount of polymerizable double bonds, thereby reducing the overall polarity of the tear-resistant resin. Detailed Implementation

[0028] The present application will be further described in detail below with reference to preparation examples, embodiments and comparative examples.

[0029] Both C5 and C9 petroleum resins were purchased from Yunlin Chemical. The grade of C5 petroleum resin is C-110, and the grade of C9 petroleum resin is L-120.

[0030] The terpene resin was purchased from Yunlin Chemical Co., Ltd., and its brand name is T-110.

[0031] The natural rosin was purchased from Xiamen Weier Chemical Co., Ltd., brand name X, with an ester content of ≤165mgKOH / g.

[0032] The pentaerythritol rosin was purchased from Xiamen Weier Chemical Co., Ltd., brand name WR-100, with an acid value ≤16mgKOH / g. Preparation Example

[0033]

Preparation Example 1

[0034] A2. Add 50 kg of maleic pine anhydride, polyol and 0.7 kg of catalyst I obtained in A1 to the reactor, heat to 190 °C under nitrogen atmosphere and keep the temperature for 1 h, then heat to 200 °C and control the vacuum degree to 50 kPa, continue to react for 6 h, cool after the reaction to obtain rosin-based polyester intermediate with hyperbranched structure. In this preparation example, the polyol is a composition of trimethylolpropane and 1,3-propanediol, and the molar ratio of the active carboxyl equivalent of maleic anhydride to the polyol is controlled to be 1:1.2. Specifically, the molar ratio of maleic anhydride, trimethylolpropane and 1,3-propanediol is 1:0.6:0.9, that is, the polyol includes 10 kg of trimethylolpropane and 8.5 kg of 1,3-propanediol; catalyst I is stannous oxalate.

[0035] A3. 50 kg of rosin-based polyester intermediate obtained in A2, 1.8 kg of glycidyl methacrylate, 0.55 kg of catalyst II, 0.1 kg of polymerization inhibitor and 200 kg of solvent I were added to a reactor and reacted at 120 °C for 6 h under a vacuum of 50 kPa. Then the temperature was lowered to 35 °C, 7.5 kg of long-chain fatty acyl chloride and 10 kg of acid-binding agent were added, and the reaction was continued for 2 h. After the reaction was completed, the mixture was cooled, allowed to stand to separate the organic layer, and then distilled under reduced pressure to obtain the modified rosin-based polyester.

[0036] In this preparation example, catalyst II is stannous octoate; polymerization inhibitor is p-hydroxyanisole; solvent I is N,N-dimethylformamide; long-chain fatty acyl chloride is tetradecyl chloride; and acid-binding agent is triethylamine.

[0037]

Preparation Example 2

[0038] A2. Add 50 kg of maleic pine anhydride, polyol and 0.65 kg of catalyst I obtained in A1 to the reactor, heat to 175 °C under nitrogen atmosphere and keep the reaction at this temperature for 2 h, then heat to 220 °C and control the vacuum degree to 50 kPa, continue the reaction for 4 h, cool after the reaction is completed to obtain rosin-based polyester intermediate with hyperbranched structure. In this preparation example, the polyol is specifically a composition of pentaerythritol, glycerol, and ethylene glycol, and the molar ratio of the active carboxyl equivalent of maleic anhydride to the polyol is controlled to be 1:1.3. Specifically, the molar ratio of maleic anhydride, pentaerythritol, glycerol, and ethylene glycol is 1:0.2:0.5:0.8, that is, the polyol includes 3.4 kg of pentaerythritol, 5.75 kg of glycerol, and 6.2 kg of ethylene glycol; catalyst I is stannous oxalate.

[0039] A3. 50 kg of rosin-based polyester intermediate obtained in A2, 1.75 kg of glycidyl methacrylate, 0.52 kg of catalyst II, 0.1 kg of polymerization inhibitor and 200 kg of solvent I were added to a reaction vessel and reacted at 135 °C for 4 h under a vacuum of 50 kPa. Then the temperature was lowered to 50 °C, 6 kg of long-chain fatty acyl chloride and 12 kg of acid-binding agent were added, and the reaction was continued for 1 h. After the reaction was completed, the mixture was cooled, allowed to stand to separate the organic layer, and distilled under reduced pressure to obtain the modified rosin-based polyester.

[0040] In this preparation example, catalyst II is stannous octoate; polymerization inhibitor is p-hydroxyanisole; solvent I is N,N-dimethylformamide; long-chain fatty acyl chloride is dodecyl chloride; and acid-binding agent is triethylamine.

[0041]

Preparation Example 3

[0042] In this preparation example, the polyol is a composition of pentaerythritol, trimethylolpropane, and ethylene glycol, and the molar ratio of the active carboxyl equivalent of maleic anhydride to the polyol is maintained at 1:1.2. Specifically, the molar ratio of maleic anhydride, pentaerythritol, trimethylolpropane, and ethylene glycol is 1:0.1:0.8:0.4, that is, the polyol includes 1.7 kg pentaerythritol, 13.4 kg trimethylolpropane, and 3.1 kg ethylene glycol.

[0043]

Preparation Example 4

[0044] In this preparation example, the polyol is a combination of pentaerythritol and trimethylolpropane, and the molar ratio of the active carboxyl equivalent of maleic anhydride to the polyol is maintained at 1:1.2. Specifically, the molar ratio of maleic anhydride, pentaerythritol and trimethylolpropane is 1:0.3:0.8, that is, the polyol includes 5.1 kg of pentaerythritol and 13.4 kg of trimethylolpropane.

[0045]

Preparation Example 5

[0046] In this preparation example, the polyol is a combination of pentaerythritol and trimethylolpropane, and the molar ratio of the active carboxyl equivalent of maleic anhydride to the polyol is maintained at 1:1.2. Specifically, the molar ratio of maleic anhydride, pentaerythritol and trimethylolpropane is 1:0.6:0.4, that is, the polyol includes 10.2 kg of pentaerythritol and 6.7 kg of trimethylolpropane.

[0047]

Preparation Example 6

[0048] In this preparation example, the amount of glycidyl methacrylate added is 4% of the mass of the rosin-based polyester intermediate, that is, 2 kg of glycidyl methacrylate is added in step A3 of the preparation method.

[0049]

Preparation Example 7

[0050] In this preparation example, the amount of glycidyl methacrylate added is 2% of the mass of the rosin-based polyester intermediate, that is, 1 kg of glycidyl methacrylate is added in step A3 of the preparation method.

[0051]

Preparation Example 8

[0052] In this preparation example, the long-chain fatty acyl chloride is selected as dodecyl chloride.

[0053]

Preparation Example 9

[0054] In this preparation example, the long-chain fatty acyl chloride is selected as hexadecyl chloride.

[0055]

Preparation Example 10

[0056] In this preparation example, the long-chain fatty acyl chloride is octadecyl chloride. Example

[0057]

Example 1

[0058] In this embodiment, the petroleum resin is C5 petroleum resin, the modified rosin-based polyester is prepared from [Preparation Example 1], and the initiator is azobisisobutyronitrile.

[0059] A method for preparing a tear-resistant resin includes the following steps: By weight, petroleum resin is heated to 140°C to fully melt and soften it. Modified rosin-based polyester and terpene resin are added. After they are completely melted, softened and mixed, an initiator is added. The mixture is heated to 180°C and stirred for 2 hours. After the reaction is completed, the mixture is distilled under reduced pressure to obtain the tear-resistant resin.

[0060] An application of a tear-resistant resin as an additive to improve the tear resistance of non-polar rubber.

[0061]

Example 2

[0062] In this embodiment, the petroleum resin is a composition of C5 and C9 petroleum resins, specifically comprising 50 kg of C5 petroleum resin and 15 kg of C9 petroleum resin. The modified rosin-based polyester was prepared according to [Preparation Example 2]. Benzoyl peroxide was selected as the initiator.

[0063] A method for preparing a tear-resistant resin includes the following steps: By weight, petroleum resin is heated to 140°C to fully melt and soften it. Modified rosin-based polyester and terpene resin are added. After they are completely melted, softened and mixed, an initiator is added. The mixture is heated to 180°C and stirred for 2 hours. After the reaction is completed, the mixture is distilled under reduced pressure to obtain the tear-resistant resin.

[0064] An application of a tear-resistant resin as an additive to improve the tear resistance of non-polar rubber.

[0065]

Example 3

[0066] In this embodiment, the modified rosin-based polyester was prepared from [Preparation Example 3].

[0067]

Example 4

[0068] In this embodiment, the modified rosin-based polyester was prepared from [Preparation Example 4].

[0069]

Example 5

[0070] In this embodiment, the modified rosin-based polyester was prepared from [Preparation Example 5].

[0071]

Example 6

[0072] In this embodiment, the modified rosin-based polyester was prepared from [Preparation Example 6].

[0073]

Example 7

[0074] In this embodiment, the modified rosin-based polyester was prepared from [Preparation Example 7].

[0075]

Example 8

[0076] In this embodiment, the modified rosin-based polyester was prepared from [Preparation Example 8].

[0077]

Example 9

[0078] In this embodiment, the modified rosin-based polyester was prepared from [Preparation Example 9].

[0079]

Example 10

[0080] In this embodiment, the modified rosin-based polyester was prepared from [Preparation Example 10]. Comparative Example

[0081] Comparative Example 1 A tear-resistant resin, which differs from [Example 1] in that it does not contain modified rosin-based polyester.

[0082] In this comparative example, commercially available natural rosin was used to replace the modified rosin-based polyester in equal amounts.

[0083] Comparative Example 2 A tear-resistant resin, which differs from [Example 1] in that it does not contain modified rosin-based polyester.

[0084] In this comparative example, commercially available pentaerythritol rosin was used to replace the modified rosin-based polyester in equal amounts. Performance testing

[0085] Sample preparation: Tear-resistant resins were prepared in advance according to the various examples and comparative examples as samples for some tests. Then, rubber samples were prepared according to the formulations in Table 1. The thickness of the rubber samples was 5 mm. The raw materials in Table 1 are all commonly used raw materials in the tire industry. The tear-resistant resins in test examples 1-10 correspond to the tear-resistant resins prepared by examples 1-10. The tear-resistant resins in comparative test examples 1-2 correspond to the tear-resistant resins prepared by comparative examples 1-2. The blank test example is a control group without the addition of tear-resistant resin.

[0086] Table 1 Formulation of the rubber sample to be tested

[0087] 1. Tear resistance modification effect: The tear strength of each rubber sample was tested in accordance with GB / T 529-2008 Determination of tear strength of vulcanized rubber or thermoplastic rubber (trouser-shaped, right-angled and crescent-shaped specimens). The uncut right-angled specimen in Method B was used for testing, and the tear strength (kN / m) of each test case was recorded.

[0088] 2. Aging tear strength: Each rubber sample to be tested was placed in an oven at 105℃ for heat aging, which lasted for 48h and 72h respectively, and then its tear strength (kN / m) was retested.

[0089] 3. Tensile stress at a constant elongation: Each rubber sample was tested in accordance with GB / T 528-2009 Determination of tensile stress-strain properties of vulcanized rubber or thermoplastic rubber. The tests were conducted at 200% and 300% tensile strength, and the tensile stress (MPa) of each test case was recorded.

[0090] 4. Long-term bloom resistance test: Each rubber sample was tested in accordance with the "HG / T 4620-2014 Test method for bloom resistance of rubber parts of footwear". The test was conducted using the constant temperature and humidity method of method B, and the test time was 168 hours. The surface bloom level of each test case was observed and recorded.

[0091] Table 2 Performance test data of each rubber sample to be tested

[0092] Combining the data from Test Example 1, Comparative Test Examples 1-2, the blank test example, and Table 2, it can be seen that by sequentially modifying natural rosin with maleic anhydride and polyol to form a hyperbranched structure, and then combining it with glycidyl methacrylate and long-chain fatty acyl chloride end-capping modification, the resulting modified rosin-based polyester, compared with traditional petroleum-rosin tear-resistant resins or petroleum-rosin polyol ester tear-resistant resins, not only has a better tear resistance improvement effect in the modification of non-polar rubber, but also retains a relatively excellent tear resistance effect after heat aging. In addition, it can slightly increase the mechanical modulus of rubber, and the blooming of rubber is easier to control, making it more suitable for tear resistance modification of non-polar rubber for tires.

[0093] Combining the data from Test Examples 1 and 3-5 and Table 2, it can be seen that adjusting the composition and ratio of the polyol can change the branching rate of the rosin-based polyester intermediate. Increasing the proportion of components with a functionality ≥3 in the polyol helps to further improve the tear resistance modification effect of the prepared resin. However, if the proportion of pentaerythritol is too high, it may lead to excessively high branching rate and steric hindrance between branches in the rosin-based polyester intermediate, affecting the subsequent grafting and end-capping modification of glycidyl methacrylate and long-chain fatty acyl chloride, resulting in increased polarity of the final modified rosin-based polyester, thus exhibiting a slight blooming problem.

[0094] Combining the data from Test Examples 4 and 6-7 and Table 2, it can be seen that the amount of glycidyl methacrylate added affects the amount of double bond grafting in the modified rosin-based polyester, thereby affecting the crosslinking properties of the resin with petroleum resin and in the rubber system. Appropriately increasing the amount of glycidyl methacrylate added is beneficial for appropriately increasing the tensile stress of the rubber system; however, excessive addition will reduce the tear resistance improvement effect of the resin and may also easily lead to slight blooming.

[0095] Combining the data from Test Examples 4 and 8-10 and Table 2, it can be seen that the carbon chain length of long-chain fatty acyl chlorides affects the polarity and compatibility of the modified resin. Increasing the carbon chain length of long-chain fatty acyl chlorides helps reduce the polarity of the modified rosin-based polyester, thereby improving its compatibility with non-polar rubbers, and also enhancing the tear resistance modification effect. However, when the carbon chain length increases to C18, although the tear resistance of the tested rubber sample remains at a good level, its performance is lower than that with long-chain fatty acyl chlorides containing C14 or C16, and it is also prone to causing slight blooming. Overall, when tetradecyl chloride or hexadecyl chloride is used for secondary end-capping modification, the modification effects of the tear-resistant resin in all aspects can reach a superior level.

[0096] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this specific embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A tear-resistant resin, characterized in that, Includes the following quantities of raw materials: 50-65 parts petroleum resin, 30-40 parts modified rosin-based polyester, 3-10 parts terpene resin, and 0.5-2 parts initiator; The modified rosin-based polyester is prepared by reacting natural rosin with maleic anhydride to generate maleic pimecrolic anhydride, then reacting the maleic pimecrolic anhydride with a polyol to form a hyperbranched structure, and then modifying it with glycidyl methacrylate and long-chain fatty acyl chloride containing C12-C18.

2. The tear-resistant resin according to claim 1, characterized in that: The polyol includes one or more combinations of ethylene glycol, 1,3-propanediol, glycerol, trimethylolpropane and pentaerythritol, and the molar ratio of the active carboxyl equivalent of the maleic anhydride to the molar amount of the hydroxyl group of the polyol is 1:(1.2-1.4).

3. The tear-resistant resin according to claim 1, characterized in that: The long-chain fatty acyl chloride is specifically selected from long-chain fatty acyl chlorides containing C14-C16.

4. The tear-resistant resin according to claim 1, characterized in that: The preparation method of the modified rosin-based polyester includes the following steps: A1. Add natural rosin to the reaction vessel, heat it under an inert atmosphere to melt and soften it, add maleic anhydride and acetic acid in batches while stirring, heat to 160-175℃ and keep it at the temperature under reflux for 2-4 hours after the addition is complete, cool to 100-120℃, add acetic acid and stir to mix, cool to crystallize, filter under reduced pressure, wash, and obtain maleic anhydride; A2. Add the maleic anhydride, polyol and catalyst I obtained in A1 to the reactor, heat to 175-190℃ under an inert atmosphere and keep the reaction at this temperature for 1-2 hours, heat to 200-220℃ and control the vacuum degree to 1-100kPa, and continue to keep the reaction at this temperature for 4-6 hours. After the reaction is completed, cool to obtain a rosin-based polyester intermediate containing a hyperbranched structure. A3. The rosin-based polyester intermediate obtained in A2, along with the glycidyl methacrylate, catalyst II, polymerization inhibitor, and solvent I, are added to a reaction vessel. The reaction is carried out at 120-140°C for 4-6 hours under a vacuum of 1-100 kPa. Then, the temperature is lowered to 35-50°C, and the long-chain fatty acyl chloride and acid-binding agent are added. The reaction is continued for 1-2 hours. After the reaction is completed, the mixture is cooled, allowed to stand to separate the organic layer, and then distilled under reduced pressure to obtain the modified rosin-based polyester.

5. The tear-resistant resin according to claim 4, characterized in that: In A3, the amount of glycidyl methacrylate added is 2-3.5% of the mass of the rosin-based polyester intermediate, and the amount of long-chain fatty acyl chloride added is 12-16% of the mass of the rosin-based polyester intermediate.

6. The tear-resistant resin according to claim 4, characterized in that: In A2, catalyst I is stannous oxalate; in A3, catalyst II is stannous octoate, the polymerization inhibitor is p-hydroxyanisole, and the acid-binding agent is triethylamine.

7. The tear-resistant resin according to claim 1, characterized in that: The petroleum resin is one of C5 petroleum resin, or a combination of C5 petroleum resin and C9 petroleum resin.

8. The tear-resistant resin according to claim 1, characterized in that: The initiator is one of azobisisobutyronitrile or benzoyl peroxide.

9. A method for preparing a tear-resistant resin, used to prepare the tear-resistant resin as described in any one of claims 1-8, characterized in that, Includes the following steps: By weight, petroleum resin is heated to 120-150℃ to fully melt and soften it. Modified rosin-based polyester and terpene resin are added. After they are completely melted, softened and mixed, an initiator is added. The mixture is heated to 160-180℃ and stirred for 2-4 hours. After the reaction is completed, the mixture is distilled under reduced pressure to obtain the tear-resistant resin.

10. An application of a tear-resistant resin, suitable for use with the tear-resistant resin as described in any one of claims 1-8, characterized in that: Used as an additive to improve the tear resistance of non-polar rubber.

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