Preparation method of modified C5 petroleum resin and application of modified C5 petroleum resin in hot melt adhesive

Abstract

The invention relates to the field of adhesive preparation, in particular to a preparation method of modified C5 petroleum resin and application of the modified C5 petroleum resin in a hot melt adhesive. According to the method, high-quality synthesis of the C5 petroleum resin under mild conditions is realized by adopting the eutectic solvent catalyst containing AlCl3, so that the softening point of the synthesized petroleum resin is relatively high, and the chromaticity is relatively low; by combining the use of an isoamylene / maleic anhydride combined modifier system, the performance of the C5 resin can be comprehensively improved, and the C5 resin can be more easily matched with the requirements of application scenes, especially the application in hot melt adhesives.

Description

Technical Field

[0001] This invention relates to the field of adhesive preparation, specifically to a method for preparing modified C5 petroleum resin and its application in hot melt adhesives. Background Technology

[0002] In recent years, with the rapid development of the ethylene industry, C5 petroleum resins have attracted much attention in the fields of hot melt adhesives and pressure-sensitive adhesives due to their excellent tackifying properties, weather resistance, and low cost. However, existing technologies still have significant shortcomings in catalyst selection, resin modification processes, and hot melt adhesive performance optimization, specifically in the following aspects: Traditional C5 petroleum resin polymerization often employs Friedel-Crafts catalysts (such as AlCl3 and BF3), but these catalysts suffer from problems such as vigorous reactions and easy gel formation. For example, patent CN1923869A synthesizes resin using a mixed C10-C20 composition, but requires low-temperature polymerization to avoid local overheating, resulting in low raw material utilization and poor product compatibility. Furthermore, hydrogenation catalysts such as the Pt / Pd noble metal system (CN107876056A) are expensive, while nickel-based catalysts (CN102453217B) are prone to resin rearrangement due to surface acidity, leading to a decrease in softening point.

[0003] Existing modification methods mainly rely on chemical grafting and blending, but these methods suffer from complex processes and limited performance improvements. For example, patent CN102153710A, which modifies resins by grafting maleic anhydride, requires high-temperature (100-200℃) addition of the initiator, which can easily lead to a darkening of the resin's color. Physical blending methods (such as CN101659736A, which modifies waste polystyrene) are low-cost but have poor compatibility. Furthermore, while the traditional two-step hydrogenation process (such as patent CN109999820B) can improve color, it is time-consuming and results in significant loss of softening point.

[0004] Unmodified C5 resin lacks polar groups in its molecular structure, resulting in poor compatibility with nonpolar elastomers and short holding time in hot melt adhesives. Existing technologies improve compatibility by introducing aromatic hydrocarbons (such as styrene), but the resin's aromatic hydrocarbon content is insufficient, making it difficult to balance initial tack and holding power. Furthermore, traditional resin waxes have a narrow wax mist range and are prone to softening and failure at high temperatures, limiting their application in industrial adhesives. In summary, existing C5 petroleum resin preparation technologies suffer from drawbacks such as unbalanced catalyst performance, complex modification processes, insufficient product performance, and poor environmental friendliness. There is an urgent need to develop an efficient, low-cost modification method that balances compatibility, thermal stability, and environmental requirements to expand its application in the high-end hot melt adhesive field. Summary of the Invention

[0005] Based on the problems summarized above, this invention provides a method for preparing modified C5 petroleum resin and its application in hot melt adhesives. Its main feature is that by using a eutectic solvent catalyst containing AlCl3, combined with an isopentenyl / maleic anhydride co-modifier system, the comprehensive performance of C5 petroleum resin is improved, making it easier to match the needs of application scenarios, especially in the application of hot melt adhesives.

[0006] The specific technical solution is as follows: A method for preparing modified C5 petroleum resin, using a eutectic solvent containing aluminum trichloride as a catalyst, and using isopentenene and maleic anhydride as modifiers.

[0007] Furthermore, the preparation method includes the following steps: S1: The crude C5 fraction is distilled under atmospheric pressure and then further distilled to obtain a multi-component solvent and a distilled C5 fraction; S2: Anhydrous aluminum trichloride and urea are mixed in a certain proportion to obtain a eutectic solvent catalyst; S3: The multi-component solvent obtained in S1 is divided into solvent C and solvent D. 15wt% of toluene is mixed with solvent C to form mixed solvent A. Then, solvent D is mixed with the distilled C5 fraction and isopentenyl modifier obtained in S1 to form mixture B. S4: Add the mixed solvent A obtained in S3 and the eutectic solvent catalyst obtained in S2 to the reactor for ultrasonic pretreatment, and then gradually add the mixture B obtained in S3 to the reactor under constant temperature. The polymerization reaction is carried out under nitrogen atmosphere for 1.5 hours. S5: After the reaction in S4 is completed, water is added to terminate the reaction. After cooling to room temperature, centrifugation is performed to recover the eutectic solvent catalyst. S6: The remaining reactants after S5 catalyst recovery are washed with sodium hydroxide solution, then washed with water until the washing solution is neutral, then an antioxidant is added and distilled, and finally stripped and dried to obtain C5 matrix resin. S7: After pretreatment of the C5 matrix resin and maleic anhydride powder obtained in S6, add them to the reactor in proportion, then add the initiator, heat to 220°C under nitrogen atmosphere, stir at 150 rpm for 2 hours, and after the reaction is completed, quickly cool down to 80°C and add hydroquinone ethanol solution as the terminator and stir for 15 minutes. S8: Using a Soxhlet extractor, the product after the S7 termination reaction was refluxed and extracted for 6 hours with acetone as solvent, and then vacuum dried at 100°C for 4 hours to obtain modified C5 petroleum resin.

[0008] Furthermore, the atmospheric distillation described in S1 has reaction parameters including a reaction pressure of 0.1 MPa and a reaction temperature of 90°C. The distillation described in S1 has reaction parameters including a reaction pressure of -5 kPa and a reaction temperature of 70°C.

[0009] Furthermore, the anhydrous aluminum trichloride and urea described in S2 are stirred and mixed in a ratio of 1:2 molar ratio of anhydrous aluminum trichloride to urea.

[0010] Furthermore, solvent C in S3 accounts for 50-70% of the total amount of the multi-component solvent; The isopentenyl modifier described in S3 is added in an amount of 10-20 wt.

[0011] Furthermore, the eutectic solvent catalyst described in S4 is added in an amount of 1.1–1.5 wt%. The parameters described in S4, which involve gradually adding the solution dropwise into the reactor, include an initial dropping rate of 3–5 mL / min and a dropping time of 100–120 minutes.

[0012] Furthermore, the centrifugal separation described in S5 includes parameters such as a set rotation speed of 8000 rpm and a centrifugation time of 10 minutes.

[0013] Furthermore, the sodium hydroxide solution described in S6 is a solution containing 2 wt% sodium hydroxide; The antioxidant described in S6 is added in an amount of 0.5 wt%. The distillation described in S6 is set at a temperature of 90°C; The stripping process described in S6 has a temperature set at 260°C.

[0014] Furthermore, the proportion of the addition to the reactor as described in S7 is 90-110:1-5 by mass. The addition of the initiator mentioned in S7 specifically refers to the addition of 1,4-di-tert-butylperoxyisopropylbenzene initiator, with an addition amount of 0.1 to 0.5 wt% of the C5 matrix resin mentioned in S7.

[0015] The present invention also provides an application of modified C5 petroleum resin in hot melt adhesives, wherein the modified C5 petroleum resin is prepared by the above preparation method and used as a resin tackifier for hot melt adhesives.

[0016] Compared with the prior art, the present invention has the following beneficial effects: (1) The present invention achieves high-quality synthesis of C5 petroleum resin under mild conditions by using a low eutectic solvent catalyst containing AlCl3, resulting in a higher softening point and lower color of the synthesized petroleum resin; moreover, the low eutectic solvent catalyst generates less waste, is easy to recycle and reuse, and has a lower cost.

[0017] (2) The present invention adopts an isopentenyl / maleic anhydride combined modifier system. Isoprene can adjust the ratio between diene and monoolefin in the system to achieve the purpose of reasonably controlling the molecular weight and molecular weight distribution of petroleum resin, eliminating the negative effects of maleic anhydride modifier on properties such as color, improving the overall performance of the resin, and making it easier to match the needs of application scenarios when the resin is used, especially in the application of hot melt adhesive. Attached Figure Description

[0018] Figure 1 This is a flowchart of a method for preparing modified C5 petroleum resin according to the present invention; Figure 2 This is a Fourier transform infrared spectrum of a modified C5 petroleum resin according to the present invention. Detailed Implementation

[0019] The following embodiments further explain and illustrate the technical solutions of the present invention. It should be specifically noted that each specific embodiment is a concretization and explanation of the technical solution and should not be considered as a limitation on the scope of protection of the present invention. Those skilled in the art still have the right to modify the technical solutions of these embodiments and make equivalent substitutions for some or all of the technical features, and these modifications or substitutions do not change the essence of the corresponding technical solutions, nor do they cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions described in the present invention.

[0020] This invention proposes a method for preparing modified C5 petroleum resin and its application in hot melt adhesives, as shown in the appendix. Figure 1 The diagram shows a process for preparing modified C5 petroleum resin, with detailed preparation steps as follows: 1. Raw material preparation and pretreatment: 1.1 Raw material selection The main raw material for resin synthesis is the C5 fraction produced by ethylene cracking, whose main components are isoprene, dicyclopentadiene, isoprene, and cyclopentene. The active monomer enrichment fraction after distillation is used as the main raw material for synthesis, and the fraction after removing dienes is used as the solvent to maximize utilization. The catalyst system is selected as a eutectic solvent containing AlCl3, and the modifiers are isoprene and maleic anhydride.

[0021] 1.2 Crude fraction distillation pretreatment Primary distillation column impurity removal: Atmospheric distillation is carried out at a pressure of 0.1 MPa and a temperature of 80-100℃ to separate light components with boiling points <35℃, including low-boiling-point impurities such as isopentane and cyclopentane.

[0022] Extraction of active components by distillation column: Distillation pressure set to -5 kPa, temperature set to 60-80℃, and collection of active monomer enriched fractions with boiling point range of 100-140℃.

[0023] Stabilization treatment: Add 0.05 wt% of hydroquinone, a polymerization inhibitor, to the fraction to prevent self-polymerization.

[0024] After pretreatment, the C5 fraction is separated into two parts: a multi-component solvent fraction and a purified C5 fraction. The main components of these fractions are as follows: Table 1 Main components of multi-component solvents Components content(%) Components content(%) isopentane 22.12 2-Methylpentane 1.82 n-Pentane 20.18 transpentadiene-1,3 1.51 Cyclopentane 15.03 cispentene-2 1.18 3-Methylpentane 11.74 n-Hexane 0.93 cyclopentene 8.72 malebutene-2 0.51 1-Pentene 3.19 3-Methyl-1-butene 0.41 transpentene-2 2.93 Butadiene-1,2 0.36 cispentadiene-1,3 1.91 Isoprene 0.30 other 7.16 Table 2. Main components of the C5 fraction from distillation Components Content (wt%) Components Content (wt%) transpentadiene 1,3 33.76 transpentene-2 0.28 cispentadiene 1,3 25.12 Dicyclopentadiene 0.26 cyclopentene 19.45 cyclopentadiene 0.21 Cyclopentane 8.01 Isoprene 0.18 2-Methyl-1-pentene 6.21 1-Pentene 0.021 1-Hexene 1.37 other 4.35 3-Methyl-1-pentene 0.41 n-Pentane 0.37 1.3 Preparation of eutectic solvent (DES) catalysts Raw material ratio: Weigh anhydrous aluminum trichloride (AlCl3, purity ≥99%) and urea precisely at a molar ratio of 1:2; where AlCl3 acts as a hydrogen bond acceptor and urea acts as a hydrogen bond donor.

[0025] Mixing process: Place urea in a dry reactor and heat it to 60°C to melt it. Slowly add AlCl3 powder while stirring at 200 rpm. Then raise the temperature to 80°C and continue stirring for 2 hours until the system changes from turbid to a transparent and homogeneous liquid. Finally, seal and store the prepared DES catalyst in a dry nitrogen environment to avoid moisture absorption and failure.

[0026] In the above steps, the -NH2 in urea and the Cl⁻ in AlCl3 combine through hydrogen bonds to form a [AlCl3·2urea]⁻ complex structure, releasing H⁺ to provide an acidic environment (pH≈1.5). Compared with AlCl3 alone, a traditional Lewis acid catalyst, the DES catalyst has a milder reaction and is less likely to cause side reactions. The DES catalyst has high dispersibility and can be uniformly distributed in the reaction system, avoiding local overheating. AlCl3 alone requires a large amount, which can easily generate a large amount of wastewater and result in a dark resin color and high ash content after the reaction. In addition, the DES catalyst can be recycled and reused.

[0027] 2. Catalytic polymerization 2.1 Preparation of Solvents and Mixtures Mix 15 wt% toluene with the pretreated multi-component solvent from the previous step to form mixed solvent A, wherein the amount of multi-component solvent added is 50-70% of the total amount added in the reaction; then mix the remaining multi-component solvent with the pretreated distillation C5 fraction from the previous step and 10-20 wt% isopentenyl modifier to form mixture B.

[0028] 2.2 Addition of catalyst At room temperature, first add mixed solvent A into the reactor, then add 1.1 to 1.5 wt% of DES catalyst into the reaction system. At this time, turn on the ultrasonic dispersion device, set the frequency to 40 kHz and the power to 100 W, and perform ultrasonic pretreatment for 10 minutes to ensure uniform dispersion of the catalyst.

[0029] 2.3 Polymerization reaction Heat the reactor to 45°C using a constant temperature water bath and maintain the temperature. Then, replace the air in the reactor with nitrogen three times to maintain a slight positive pressure (0.05 MPa) to prevent oxygen from entering. At this time, gradually add the mixture B to the reactor using a constant pressure funnel. The initial dropping rate is 3-5 mL / min, and the dropping time is controlled at 100-120 minutes. After the dropping is completed, maintain the temperature for polymerization reaction for 1.5 hours.

[0030] 2.4 Termination and Catalyst Recovery: The reaction was terminated by adding water. After cooling to room temperature, the DES catalyst was recovered by centrifugation at a speed of 8000 rpm for 10 minutes.

[0031] 2.5 Washing, distillation and stripping treatment The catalyst-recovered material was washed with a 2 wt% NaOH solution. After alkaline washing, it was washed with water 3–5 times to remove residual alkali until the pH of the washing solution was neutral. Then, 0.5 wt% antioxidant 330 was added to the washed material, and distillation was carried out at 90°C to remove the solvent and unreacted monomers. Finally, steam was introduced, and stripping was performed at 260°C. After drying, C5 matrix resin was obtained.

[0032] In the above steps, the addition of isopentenyl is used to modify and adjust the ratio between dienes and monoolefins in the system, so as to achieve reasonable control of the molecular weight and molecular weight distribution of petroleum resin. Combined with the use of eutectic solvent, it prepares for subsequent maleic anhydride grafting modification, eliminates the negative effects of maleic anhydride on properties such as color after its addition to the system, and improves the overall performance of the resin.

[0033] 3. Ester grafting modification 3.1 Preparations before grafting reaction Pretreatment of matrix resin: The obtained C5 matrix resin is crushed into particles with a particle size ≤2 mm and vacuum dried at 80℃ for 4 hours to reduce its moisture content to ≤0.1%; this treatment can increase the surface area of ​​the resin, ensure uniform contact with maleic anhydride, and avoid local overheating that could lead to side reactions.

[0034] Maleic anhydride (MAH) activation: Maleic anhydride powder is melted into a liquid at 60°C, and 0.1 wt% of hindered phenolic antioxidant BHT is added to inhibit the self-polymerization of MAH into oligomers at high temperature, ensuring an effective grafting rate.

[0035] 3.2 Grafting reaction The prepared C5 matrix resin and maleic anhydride were added to a reactor at a mass ratio of 90-110:1-5, and the initiator 1,4-bis-tert-butylperoxyisopropylbenzene (BIPB) was added at a dosage of 0.1-0.5 wt% of the C5 matrix resin. The air in the reactor was purged with high-purity nitrogen three times to ensure that the oxygen content was <50 ppm. The temperature was increased to 220°C at a rate of 5°C / min, and the stirring rate was maintained at 150 rpm for 2 hours. After the reaction was completed, the temperature was rapidly reduced to 80°C, and 0.5 wt% hydroquinone ethanol solution as a terminator was added and stirred for 15 minutes.

[0036] A Soxhlet extractor was used to reflux extract with acetone as solvent for 6 hours to remove unreacted MAH and homopolymer, ensuring that the residual MAH content was ≤0.3%. Finally, the purified ester-grafted C5 resin was obtained by vacuum drying at 100℃ for 4 hours.

[0037] In the above steps, to adapt to the application scenarios of hot melt adhesive tackifying resins, it is necessary to improve the poor compatibility between the C5 matrix resin and polar polymers. Maleic anhydride grafting modification can introduce anhydride groups into the resin molecular chain, significantly enhancing its polarity and improving the dispersibility of the resin in the hot melt adhesive system, thereby increasing the bonding strength. Maleic anhydride grafting modification increases the rigidity and crosslinking density of the molecular chain, which can raise the softening point of the resin to match the application environment of hot melt adhesives. Although maleic anhydride modification increases color, the color of the matrix resin can be greatly reduced by the modification of isopentenene and the use of eutectic solvent catalysts in the aforementioned steps, which can compensate for the negative impact of maleic anhydride.

[0038] Example 1 A method for preparing modified C5 petroleum resin is as follows: S1: The C5 fraction from ethylene cracking by-products is subjected to atmospheric distillation at a pressure of 0.1 MPa and a temperature of 90°C to separate the light components with a boiling point <35°C; then, it is subjected to rectification distillation at a pressure of -5 kPa and a temperature of 70°C. After the rectification, 0.05 wt% of the polymerization inhibitor hydroquinone is added to the fraction. After the pretreatment, a multi-component solvent and the rectification C5 fraction are obtained.

[0039] S2: Accurately weigh anhydrous aluminum trichloride and urea at a molar ratio of 1:2. Place the urea in a dry reaction vessel and heat it to 60°C to melt it. Slowly add AlCl3 powder while mixing with a stirring rate of 200 rpm. Then raise the temperature to 80°C and continue stirring for 2 hours until the system changes from turbid to a transparent and homogeneous liquid, thus obtaining the DES catalyst.

[0040] S3: Mix 15 wt% toluene with 60% of the total reaction amount of multi-component solvent to form mixed solvent A. Then mix the remaining multi-component solvent with distilled C5 fraction and 15 wt% isopentenyl modifier to form mixture B.

[0041] S4: At room temperature, first add mixed solvent A to the reactor, then add 1.3 wt% DES catalyst to the reaction system, sonicate for 10 minutes, set the frequency to 40 kHz and the power to 100 W; then heat the reactor to 45°C using a constant temperature water bath and maintain it, replace the air in the reactor with nitrogen three times, and gradually add the mixture B dropwise to the reactor using a constant pressure funnel, with an initial drop rate of 4 mL / min and a drop time controlled at 110 minutes. After the drop is completed, maintain the temperature for polymerization reaction for 1.5 hours.

[0042] S5: Add water to terminate the reaction. After cooling to room temperature, recover the DES catalyst by centrifugation at a speed of 8000 rpm for 10 minutes.

[0043] S6: Wash the remaining material with 2 wt% NaOH solution, and then wash with water until the pH of the washing solution is neutral; add 0.5 wt% antioxidant 330 to the washed material and distill at 90℃; finally, pass steam through and strip at 260℃, and dry to obtain C5 matrix resin.

[0044] S7: The prepared C5 matrix resin was pulverized into particles with a particle size ≤2 mm and vacuum dried at 80℃ for 4 hours. Then, maleic anhydride powder was melted into liquid at 60℃, and 0.1 wt% of hindered phenolic antioxidant BHT was added. After pretreatment, it was added to the reactor at a mass ratio of 100:3, and 0.3 wt% of initiator BIPB of C5 matrix resin was added. The air in the reactor was replaced three times with high-purity nitrogen. The temperature was raised to 220℃ at a rate of 5℃ / min, and the stirring rate was maintained at 150 rpm for 2 hours. After the reaction was completed, the temperature was rapidly reduced to 80℃, and 0.5 wt% of hydroquinone ethanol solution as a terminator was added and stirred for 15 minutes.

[0045] S8: Modified C5 petroleum resin was obtained by reflux extraction with acetone as solvent using a Soxhlet extractor for 6 hours, and finally vacuum drying at 100℃ for 4 hours.

[0046] Example 2 The preparation method is the same as in Example 1, except that: In step S3, 15 wt% of toluene is mixed with 50% of the total reaction amount of multi-component solvent to form mixed solvent A. Then, the remaining multi-component solvent is mixed with distilled C5 fraction and 10 wt% isopentenyl modifier to form mixture B.

[0047] In step S4, 1.1 wt% of DES catalyst is added to the reaction system. The initial dropping rate was 3 mL / min, and the dropping time was controlled at 100 minutes.

[0048] In step S7, after pretreatment, the resin is added to the reactor at a mass ratio of 90:1, along with 0.1 wt% of BIPB initiator for the C5 matrix resin.

[0049] All other specific steps are the same.

[0050] Example 3 The preparation method is the same as in Example 1, except that: In step S3, 15 wt% of toluene is mixed with 70% of the total reaction amount of the multi-component solvent to form mixed solvent A. Then, the remaining multi-component solvent is mixed with the C5 fraction of distillation and 20 wt% of isopentenyl modifier to form mixture B.

[0051] In step S4, 1.5 wt% of DES catalyst is added to the reaction system. The initial dropping rate was 5 mL / min, and the dropping time was controlled at 120 minutes.

[0052] In step S7, after pretreatment, the resin is added to the reactor at a mass ratio of 110:5, along with 0.5 wt% of BIPB initiator for the C5 matrix resin.

[0053] All other specific steps are the same.

[0054] Example 4 The preparation method is the same as in Example 1, except that: In step S3, 15 wt% of toluene is mixed with 50% of the total reaction amount of multi-component solvent to form mixed solvent A. Then, the remaining multi-component solvent is mixed with distilled C5 fraction and 20 wt% isopentenyl modifier to form mixture B.

[0055] In step S4, 1.2 wt% of DES catalyst is added to the reaction system. The initial dropping rate was 3 mL / min, and the dropping time was controlled at 120 minutes.

[0056] In step S7, after pretreatment, the resin is added to the reactor at a mass ratio of 95:2, along with 0.2 wt% of BIPB initiator for the C5 matrix resin.

[0057] All other specific steps are the same.

[0058] Example 5 The preparation method is the same as in Example 1, except that: In step S3, 15 wt% of toluene is mixed with 70% of the total reaction amount of the multi-component solvent to form mixed solvent A. Then, the remaining multi-component solvent is mixed with the C5 fraction of distillation and 10 wt% of isopentenyl modifier to form mixture B.

[0059] In step S4, 1.4 wt% of DES catalyst is added to the reaction system. The initial dropping rate was 5 mL / min, and the dropping time was controlled at 100 minutes.

[0060] In step S7, after pretreatment, the resin is added to the reactor at a mass ratio of 105:4, along with 0.4 wt% of BIPB initiator for the C5 matrix resin.

[0061] All other specific steps are the same.

[0062] Comparative Example 1 The preparation steps are the same as in Example 1, except that DES catalyst is not prepared in step S2; in step S4, 1.5 wt% AlCl3 catalyst is added to the reaction system, the temperature of the constant temperature water bath heating reactor is increased to 55°C, and the time of constant temperature polymerization reaction is extended to 2 hours; all other steps are the same.

[0063] Comparative Example 2 The preparation steps are the same as in Example 1, except that 15 wt% isopentenyl modifier is not added in step S3, while the other steps are the same.

[0064] Comparative Example 3 The preparation steps are the same as in Example 1, except that steps S7 and S8 are omitted.

[0065] Application Example 1 The resins prepared in Examples 1-5 and Comparative Examples 1-3 were used to prepare hot melt adhesives. The formulation composition included (parts by weight): 40 parts of the prepared resin, 45 parts of SIS block copolymer, 5 parts of polyα-methylstyrene resin, 0.6 parts of antioxidant, and 12 parts of paraffinic oil plasticizer. The preparation process includes: melting paraffin-based oil plasticizer and antioxidant at 160°C, adding SIS block copolymer and poly-α-methylstyrene resin, stirring until completely melted; adding the prepared resin, vacuum degassing at 180°C for 30 minutes, and extruding and granulating.

[0066] Experimental Example 1 Samples of the C5 matrix resins prepared in step S6 of Example 1, Comparative Example 1, and Comparative Example 2 were taken respectively, and the softening point and Gardner color of the samples were measured, specifically in accordance with the national standards GB / T 24138-2022 "Petroleum Resins" and GB / T22295-2008 "Method for Determination of Color of Transparent Liquids (Gardner Color)". As shown in Table 3, the test results indicate that the use of AlCl3 catalyst instead of DES catalyst in Comparative Example 1 resulted in a deeper color, while Comparative Example 2, which did not add isopentenyl modifier, had a certain impact on both color and softening point. It is evident that DES catalyst and isopentenyl modifier have a significant effect on improving the color and softening point properties of C5 matrix resin.

[0067] Table 3. Comparison of softening point and Gardner colorimetric results of C5 matrix resins prepared in Example 1, Comparative Example 1, and Comparative Example 2. experimental group Softening point (°C) Chromaticity (Ga) Example 1 91 3- Comparative Example 1 97 4- Comparative Example 2 86 3 Experiment Example 2 The modified C5 petroleum resin prepared in Example 1 was used as a sample for testing the maleic anhydride grafting rate. The analysis and calculation were performed using chemical titration. The specific steps are as follows: The sample was heated under reflux with xylene for 2 hours to ensure complete hydrolysis; excess KOH-ethanol standard solution was added, and the remaining alkaline solution was back-titrated with HCl-isopropanol using phenolphthalein as an indicator; the calculation formula is: ,in, V 0 The blank titration volume is... V For the sample titration volume, M MAH =98.06 g / mol. After testing, the grafting rate of maleic anhydride in the sample of Example 1 was 12.8%, which meets the requirements for hot melt adhesive tackifier applications, maintaining a balance between initial tack and holding power.

[0068] The modified C5 petroleum resin prepared in Example 1 was used as a sample for molecular weight distribution testing. Gel permeation chromatography (GPC) was used for the testing, and the testing method is as follows: Preparation of standard samples: Select polystyrene (PS) standards (molecular weight range 300-200,000), dissolve them in tetrahydrofuran (THF), and prepare a solution of 0.5-2 mg / mL.

[0069] Chromatographic conditions: Chromatographic column: silica gel column; Mobile phase: tetrahydrofuran (flow rate 1.0 mL / min, column temperature 30~35℃); Detector: Differential refractive index detector (RI).

[0070] Sample preparation: Dissolve C5 resin in THF, filter, and then inject for analysis.

[0071] Data processing: Molecular weight distribution parameters are calculated using the standard curve equation.

[0072] After testing, the sample of Example 1 had a weight-average molecular weight of 2731, a number-average molecular weight of 1134, a Z-average molecular weight of 4925, and a molecular weight distribution of 2.16, which meets the application scenarios where hot melt adhesives have high flowability requirements.

[0073] The modified C5 petroleum resin prepared in Example 1 was used as a sample for Fourier transform infrared spectroscopy (FTIR) analysis. The experimental method referred to the national standard GB / T 32199-2015: "General Rules for Qualitative Analysis Techniques of Infrared Spectroscopy"; as attached. Figure 2 The image shows the Fourier transform infrared spectrum of the modified C5 petroleum resin. The stretching vibration absorption peak of the methyl C-H single bond is at 2952 cm⁻¹. -1 The absorption peak of deformation vibration is 1463 cm⁻¹. -1 The stretching vibration absorption peak of the methylene carbon-hydrogen single bond is at 2864 cm⁻¹. -1 The absorption peak of the double bond stretching vibration is at 1660 cm⁻¹. -1 The stretching vibration absorption peak of the benzene ring is at 1600 cm⁻¹. -1 The characteristic peak of the carboxyl group in maleic anhydride is at 1750 cm⁻¹. -1 Based on the information given in the figure, it matches the modification treatment performed in the preparation method.

[0074] Experimental Example 3 The C5 resins prepared according to the preparation methods of Examples 1-5 and Comparative Examples 1-3 were tested for softening point, color, thermal stability, wax fog point and melt viscosity at 200℃, and the overall performance of the resins was evaluated by comparison.

[0075] The softening point and color were tested according to the method described in Experimental Example 1 above. The thermal stability was tested by heating the resin continuously in flowing air at 150°C for 16 hours, followed by a measurement of its Gardner color, which was also performed using the method described above. The wax fog point was measured according to the wax fog point determination method recorded in Appendix A of the national standard GB / T 24138-2022 "Petroleum Resins". The melt viscosity at 200°C was measured using a rotational viscometer to determine the actual viscosity of the corresponding sample resin. The test comparison results are shown in Table 4.

[0076] Table 4. Comparison of experimental results of Example 3 between Examples 1-5 and Comparative Examples 1-3

[0077] The comparison results show that Comparative Example 1, using an AlCl3 catalyst, resulted in higher resin color and affected wax mist point; Comparative Example 2, lacking an isopentenyl modifier, did not achieve an ideal ratio between dienes and monoolefins, leading to a poor molecular weight distribution of the petroleum resin and affecting various performance indicators such as softening and color of the final resin; Comparative Example 3, without graft modification, resulted in lower rigidity and crosslinking density of the molecular chains, leading to a lower softening point and poorer thermal stability of the resin.

[0078] Experiment Example 4 Using the C5 resins prepared according to the preparation methods of Examples 1-5 and Comparative Examples 1-3 as raw materials, hot melt adhesives were prepared using the preparation method of Example 1, and the initial tack strength, holding strength and 180° peel strength of the hot melt adhesives were tested respectively.

[0079] Initial tack strength was tested according to national standard GB / T 31125-2014 "Test Method for Initial Tack of Adhesive Tapes (Ring Method)"; holding strength was tested according to national standard GB / T 4851-2014 "Test Method for Holding Strength of Adhesive Tapes"; 180° peel strength was tested according to national standard GB / T 2792-1998 "Test Method for 180° Peel Strength of Pressure-Sensitive Adhesive Tapes". The test comparison results are shown in Table 5.

[0080] Table 5. Comparison of experimental results of Examples 1-5 and Comparative Examples 1-3, Example 4.

[0081] The comparison results above, combined with those of Experiment 3, show that the softening point, wax fog point, and melt viscosity of Comparative Examples 1-3 were not within a suitable range, resulting in an imbalance between their initial tack strength and holding strength, ultimately leading to low peel strength. The excessively high softening point and wax fog point of Comparative Example 1 resulted in a large gap between initial tack strength and holding strength, while the excessively low softening point and wax fog point of Comparative Examples 2 and 3 resulted in low overall performance indicators.

Claims

1. A method for preparing modified C5 petroleum resin, characterized in that, A eutectic solvent containing aluminum trichloride was used as a catalyst, and isopentenene and maleic anhydride were used as modifiers.

2. The method for preparing modified C5 petroleum resin as described in claim 1, characterized in that, Includes the following steps: S1: The crude C5 fraction is distilled under atmospheric pressure and then further distilled to obtain a multi-component solvent and a distilled C5 fraction; S2: Anhydrous aluminum trichloride and urea are mixed in a certain proportion to obtain a eutectic solvent catalyst; S3: The multi-component solvent obtained in S1 is divided into solvent C and solvent D. 15wt% of toluene is mixed with solvent C to form mixed solvent A. Then, solvent D is mixed with the distilled C5 fraction and isopentenyl modifier obtained in S1 to form mixture B. S4: Add the mixed solvent A obtained in S3 and the eutectic solvent catalyst obtained in S2 to the reactor for ultrasonic pretreatment, and then gradually add the mixture B obtained in S3 to the reactor under constant temperature. The polymerization reaction is carried out under nitrogen atmosphere for 1.5 hours. S5: After the reaction in S4 is completed, water is added to terminate the reaction. After cooling to room temperature, centrifugation is performed to recover the eutectic solvent catalyst. S6: The remaining reactants after S5 catalyst recovery are washed with sodium hydroxide solution, then washed with water until the washing solution is neutral, then an antioxidant is added and distilled, and finally stripped and dried to obtain C5 matrix resin. S7: After pretreatment of the C5 matrix resin and maleic anhydride powder obtained in S6, add them to the reactor in proportion, then add the initiator, heat to 220°C under nitrogen atmosphere, stir at 150 rpm for 2 hours, and after the reaction is completed, quickly cool down to 80°C and add hydroquinone ethanol solution as the terminator and stir for 15 minutes. S8: Using a Soxhlet extractor, the product after the S7 termination reaction was refluxed and extracted for 6 hours with acetone as solvent, and then vacuum dried at 100°C for 4 hours to obtain modified C5 petroleum resin.

3. The method for preparing modified C5 petroleum resin as described in claim 2, characterized in that, The atmospheric distillation described in S1 has reaction parameters including a reaction pressure of 0.1 MPa and a reaction temperature of 90°C. The distillation described in S1 has reaction parameters including a reaction pressure of -5 kPa and a reaction temperature of 70°C.

4. The method for preparing modified C5 petroleum resin as described in claim 2, characterized in that, The anhydrous aluminum trichloride and urea described in S2 are mixed in a ratio of 1:2 molar ratio of anhydrous aluminum trichloride to urea.

5. The method for preparing modified C5 petroleum resin as described in claim 2, characterized in that, The solvent C described in S3 accounts for 50-70% of the total amount of the multi-component solvent; The isopentenyl modifier described in S3 is added in an amount of 10-20 wt.

6. The method for preparing a modified C5 petroleum resin as described in claim 2, characterized in that, The eutectic solvent catalyst described in S4 is added in an amount of 1.1–1.5 wt%. The parameters described in S4, which involve gradually adding the solution dropwise into the reactor, include an initial dropping rate of 3–5 mL / min and a dropping time of 100–120 minutes.

7. The method for preparing modified C5 petroleum resin as described in claim 2, characterized in that, The centrifugal separation described in S5 has parameters including a set rotation speed of 8000 rpm and a centrifugation time of 10 minutes.

8. The method for preparing a modified C5 petroleum resin as described in claim 2, characterized in that, The sodium hydroxide solution described in S6 is a solution containing 2 wt% sodium hydroxide; The antioxidant described in S6 is added in an amount of 0.5 wt%. The distillation described in S6 is set at a temperature of 90°C; The stripping process described in S6 has a temperature set at 260°C.

9. The method for preparing a modified C5 petroleum resin as described in claim 2, characterized in that, The proportion of S7 added to the reactor is 90-110:1-5 by mass. The addition of the initiator mentioned in S7 specifically refers to the addition of 1,4-di-tert-butylperoxyisopropylbenzene initiator, with an addition amount of 0.1 to 0.5 wt% of the C5 matrix resin mentioned in S7.

10. The application of a modified C5 petroleum resin in hot melt adhesives, characterized in that, The modified C5 petroleum resin prepared by any one of the modified C5 petroleum resin preparation methods as described in any one of claims 1 to 9 is used as a resin tackifier for hot melt adhesives.

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