Preparation method of hydrogenated petroleum resin based on D-A reaction toughening and product thereof

Abstract

The invention belongs to the technical field of petroleum resin preparation, and relates to a preparation method of hydrogenated petroleum resin based on D-A reaction toughening. Specifically, conjugated diene and a dienophile are subjected to a Diels-Alder reaction to generate a prepolymer monomer with a cyclohexene structure, cationic polymerization of the prepolymer is initiated under catalysis of a Lewis acid catalyst, a molecular chain is further increased, a D-A polymer with higher molecular weight and a specific branched structure is obtained, and deep hydrogenation is performed to obtain the high-molecular-weight and high-molecular-weight D-A polymer with a specific branched structure. The fully saturated hydrogenated petroleum resin with a rigid alicyclic structure and a flexible ester group side chain is obtained. The hydrogenated petroleum resin has good thermodynamic properties, mechanical properties and aging resistance which are synergistically optimized, meets the technical requirements of high polymer material additives, and has remarkable strategic development potential and market competitiveness in the field of refined, functionalized and green chemical materials.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of petroleum resin preparation, and relates to a preparation method of hydrogenated petroleum resin based on D-A reaction toughening and a hydrogenated petroleum resin obtained by the preparation method. BACKGROUND

[0002] The hydrogenated petroleum resin has become a key raw material in the fields of high-end adhesives, sanitary products and the like due to its light color, good thermal stability and excellent weather resistance, especially C5 hydrogenated petroleum resin or C9 hydrogenated petroleum resin. However, there are still some technical bottlenecks to be solved in the prior art: 1. the contradiction between “toughness” and “cohesion strength”: in order to obtain sufficient cohesion strength (adhesion), the resin needs a high aromatic ring content or rigid structure, but this will lead to high modulus, poor toughness and stiffness after bonding, and the experience in the scenarios of removable glue and skin glue is poor. Conversely, the pursuit of softness and toughness is insufficient in cohesion strength. 2. the contradiction between hydrogenation depth and cost: deep hydrogenation requires harsh processes of high temperature and high pressure, which is high in energy consumption and cost. If the hydrogenation is not complete, the residual unsaturated bond will become a weak point of material aging, leading to yellowing and performance degradation after long-term use. 3. dependence on plasticizers: the prior art often adds a large amount of mineral oil and other plasticizers to reduce the modulus and increase the toughness, but this will sacrifice the cohesion strength and may cause problems such as plasticizer migration, allergy and pollution. 4. dependence on raw materials: high-quality hydrogenated C9 resin is severely dependent on C9 fraction produced by ethylene cracking, and the composition fluctuation thereof will affect the uniformity and performance of the final product.

[0003] Therefore, there is an urgent need in the art for a completely new resin molecular structure design, which can essentially break the trade-off relationship between “toughness” and “strength”, and realize deep hydrogenation through a more efficient process path, so as to prepare a high-performance and high-environmental-standard petroleum resin. SUMMARY

[0004] Therefore, one of the purposes of the present application is to provide a preparation method of hydrogenated petroleum resin based on D-A reaction toughening, and the second purpose is to provide a hydrogenated petroleum resin obtained by the preparation method.

[0005] To achieve the above-mentioned purposes, the present application provides the following technical solutions:

[0006] 1. A preparation method of hydrogenated petroleum resin based on D-A reaction toughening, comprising the following steps:

[0007] a. under an inert gas atmosphere, dissolving conjugated diene monomers and dienophile monomers in an organic solvent, and reacting at 40-60℃ for 2-6 hours to obtain a D-A addition prepolymer monomer by reduced pressure distillation;

[0008] The application is innovative in the molecular structure of the product, and the introduction of flexible ester groups and other side chains endows the material with essential toughness, so as to achieve performance breakthrough. The cyclic structure generated by D-A reaction itself has excellent rigidity, providing high cohesive strength. Through such "rigidity and flexibility" molecular design, the contradiction between the strength and toughness of hydrogenated petroleum resin is solved from the root.

[0009] b. A solution of 20-50 wt % of D-A addition prepolymer monomer and dry toluene is prepared, cooled to -20℃-0℃, and stirred under inert gas; a Lewis acid catalyst is added, and after 2-4 hours of reaction, the reaction solution is slowly poured into a vigorously stirred methanol / water mixture, filtered to obtain a crude resin, and dried to constant weight to obtain a light yellow to amber solid resin;

[0010] c. The solid resin is dissolved in toluene to form a 10-20 wt % solution, which is added to a high-pressure autoclave, and a Pd / C noble metal catalyst is added for hydrogenation reaction under a hydrogen gas atmosphere;

[0011] Since the precursor is mainly aliphatic ring structure and does not contain polycyclic aromatic hydrocarbons that are difficult to hydrogenate, a hydrogenation degree of >98% can be achieved under relatively mild process conditions, so the hydrogenated petroleum resin obtained by the application has extremely high hydrogenation efficiency and excellent product quality.

[0012] The fully saturated structure of the product means extremely low odor and VOC, and when further applied to hot melt pressure sensitive adhesive, plasticizers can be greatly reduced or even completely eliminated, avoiding the risk of migration, and being particularly suitable for medical and sanitary products, with significant environmental advantages.

[0013] d. After the reaction is completed, cooling, filtration, and removal of solvents and low molecular weight substances by 2 mmHg-10 mmHg reduced pressure distillation are performed to obtain a water-white hydrogenated petroleum resin.

[0014] Preferably, in step a, the proportion of conjugated diene monomers is 30-55 wt%, and the proportion of dienophile monomers is 45-70 wt%.

[0015] Preferably, the conjugated diene monomer is one of cyclopentadiene, dicyclopentadiene, 1,3-butadiene, and isoprene.

[0016] Preferably, the dienophile monomer is one of acrylate, maleic anhydride, and fumarate.

[0017] The acrylate has a molecular formula CH2=CH-COOR, and R is an electron-donating group such as methyl or ethyl.

[0018] The fumarate can be selected from dimethyl fumarate and diethyl fumarate.

[0019] Preferably, in step a, the reduced pressure distillation condition is 2 mmHg-10 mmHg at 115-125℃.

[0020] Preferably, the Lewis acid catalyst is aluminum trichloride, boron trifluoride, zinc chloride, ferric chloride.

[0021] Preferably, in step c, the average particle size of the Pd / C noble metal catalyst used is 10-20 μm, and the Pd content is 5-10 wt%.

[0022] Preferably, in step c, the hydrogenation reaction is carried out at a temperature of 180-220℃ under a hydrogen pressure of 2.0-5.0 MPa for 4-8 hours.

[0023] The preparation method of the hydrogenated petroleum resin provided by the present application does not completely rely on traditional C5 / C9 fraction, has wide adaptability to raw materials, can flexibly regulate the softening point, polarity, compatibility, etc. of the resin through selection and proportioning of monomers, and has large product design freedom.

[0024] 2. The hydrogenated petroleum resin obtained by the preparation method of the hydrogenated petroleum resin according to any one of the above is also within the protection scope of the present application, the obtained resin is water white, has good thermal stability, has very small color change when tested at 180℃ for 72 hours, and has a yellowing index much lower than that of commercially available products.

[0025] 3. The hydrogenated petroleum resin according to any one of the above, and the hydrogenated petroleum resin obtained by the preparation method, are used in the preparation of hot melt adhesives, pressure sensitive adhesives, tackifiers, and structural adhesives. BRIEF DESCRIPTION OF DRAWINGS

[0026] In order to make the purpose, technical scheme and beneficial effects of the present application clearer, the present application provides the following drawings for illustration:

[0027] Figure 1 The infrared spectrum comparison chart of the reaction raw material mixture and the product. DETAILED DESCRIPTION

[0028] The preferred technical scheme of the embodiments of the present application will be described clearly and completely below in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without making creative efforts are within the protection scope of the present application. The experimental methods not specified in the embodiments are usually carried out according to the conventional conditions or the conditions suggested by the manufacturers. If not otherwise specified, the used equipment and raw materials can be obtained through commercial channels.

[0029] Example 1

[0030] A method for preparing a hydrogenated petroleum resin based on D-A reaction toughening, the specific steps are as follows:

[0031] Step 1, preparing a prepolymer by D-A reaction

[0032] In a 1L three-necked flask, high-purity nitrogen was introduced to replace air three times, and the reaction was continuously carried out under a nitrogen atmosphere; 300g of cyclohexane was added as a solvent into the flask, and then the following was sequentially added: conjugated diene monomer: dicyclopentadiene (DCPD), 75g; dienophile monomer: n-butyl acrylate (BA), 130g.

[0033] Stirring was started to fully dissolve the monomers. The reaction system was slowly heated to 60°C, and kept at this temperature for 4 hours. After the reaction was completed, Fourier transform infrared spectroscopy (FT-IR) was used for monitoring, as shown in the infrared spectrum comparison chart of the reaction raw material mixture and the product, it was found that the characteristic absorption peak of conjugated diene near 1640 cm⁻¹ was significantly weakened, and a strong absorption peak of ester carbonyl near 1720 cm⁻¹ appeared, indicating that the Diels-Alder (D-A) reaction was basically completed, and a D-A addition prepolymer containing cyclohexene structure and ester side chain was generated. The D-A addition prepolymer monomer was obtained by vacuum distillation at 2 mmHg-10 mmHg, 115-125°C. Figure 1

[0034] Step 2, cationic polymerization

[0035] In the reaction bottle, 50g of D-A addition prepolymer monomer and 150g of dry toluene were added, the system was cooled to -20°C to 0°C, stirring was started, and nitrogen was introduced; 0.5g of AlCl3 was dissolved in 10g of dry toluene, and was slowly added to the D-A addition prepolymer reaction solution through a constant pressure dropping funnel. During the addition process, it was observed that the viscosity of the system increased significantly. After the addition was completed, the reaction was continued at low temperature for 2-3 hours. The reaction solution was slowly poured into a vigorously stirred methanol / water (mass ratio of methanol to water was 3:1-5:1) mixture, and the crude resin was obtained by filtration. The crude resin was dried to constant weight in a vacuum oven at 60-80°C to obtain a light yellow to amber solid resin.

[0036] Step 3, deep hydrogenation

[0037] 10g of the solid resin obtained in step 2 was dissolved in 50g of toluene to form a solution, which was completely transferred to a high-pressure reaction kettle. 0.5g of a supported palladium catalyst (Pd / C, palladium content 5%) was added to the kettle. After replacing the air in the kettle with hydrogen three times, hydrogen was filled to a pressure of 3.0 MPa. Stirring was started and the temperature was raised, and the reaction temperature was controlled at 200°C for 6 hours of hydrogenation reaction. The hydrogen pressure was kept constant during the reaction.

[0038] ​Step 4, post-treatment: after the reaction is completed, cool to room temperature, recover the catalyst by filtration, and then remove the solvent and low molecular weight substances by distillation under reduced pressure of 2 mmHg-10 mmHg to obtain the final water-white hydrogenated petroleum resin. The sample of this example is denoted as Resin A.

[0039] In some embodiments, the conjugated diene monomer accounts for 30-55 wt%, and can be any one of cyclopentadiene, 1,3-butadiene, or isoprene.

[0040] In some embodiments, cyclohexane can also be replaced with toluene.

[0041] In some embodiments, the dienophile monomer accounts for 45-70 wt%, and can be any one of an acrylate (CH2=CH-COOR, R is a methyl group, an ethyl group, or other electron-donating group), maleic anhydride, or a fumarate (dimethyl fumarate, diethyl fumarate).

[0042] In the step 1 D-A reaction, the conjugated diene monomer and the dienophile monomer are dissolved in the solvent at a solute to solvent mass ratio of 1:0.54-1.22, and the reaction is carried out at 40-60°C for 2-6 hours.

[0043] In the step 2 cationic polymerization reaction, a solution of 20-50 wt% of the addition prepolymer monomer and dry toluene can be prepared, and 0.5-1.0 wt% (relative to the mass of the monomer) of a Lewis acid catalyst (such as aluminum trichloride, boron trifluoride, zinc chloride, or iron trichloride) is added to initiate cationic polymerization of the prepolymer, further growing the molecular chain, to obtain a D-A polymer with a higher molecular weight and a specific branched structure.

[0044] In the step 3 deep hydrogenation, the resin of step 2 is dissolved in toluene to form a 10-20 wt% solution, which is transferred to an autoclave, and 1-5 wt% of a Pd / C noble metal catalyst (relative to the resin) is added. The average particle size of the catalyst used can be 10-20 μm, and the Pd content in the Pd / C noble metal catalyst can be 5-10 wt%. The reaction is carried out at a mild temperature of 180-220°C and a hydrogen pressure of 2.0-5.0 MPa for 4-8 hours, which can completely saturate the unsaturated double bonds in the polymer.

[0045] Example 2: Resin preparation by adjusting the monomer ratio and type

[0046] This example aims to demonstrate that by adjusting the monomer ratio and type within a certain range, the resin performance can be flexibly controlled. The operation steps are basically the same as those of Example 1, except that the monomer feeding of step 1 is changed: conjugated diene monomer: cyclopentadiene (CPD), 75 g; dienophile monomer: diethyl fumarate (DEF), 175 g (70 wt%).

[0047] Similarly, through D-A reaction (60 °C, 4 h), cationic polymerization (AlCl3, -20 °C to 0 °C, 2.5 h) and deep hydrogenation (Pd / C catalyst, 200 °C, 3.0 MPa, 6 h) and post-treatment, the product was obtained, denoted as resin B.

[0048] Example 3: Comparative resin preparation without cationic polymerization step

[0049] This example is used for comparison to illustrate the impact of omitting the cationic polymerization step on product performance. The operation steps are basically the same as Example 1, but the cationic polymerization step in step 2 is omitted. That is, after the end of the D-A reaction in step 1, the prepolymer solution is directly subjected to the hydrogenation reaction in step 3 and the post-treatment in step 4, and the obtained product is denoted as resin C.

[0050] Comparative Example 1: Traditional hydrogenated C9 petroleum resin

[0051] A commercially available high-performance hydrogenated C9 petroleum resin (softening point about 100 °C) is selected, denoted as resin D, for performance comparison.

[0052] Comparative Example 2: Application comparison of Example 1 resin with plasticizer

[0053] In subsequent application tests, resin A prepared in Example 1 (70 wt%) is blended with 30 wt% paraffin oil, a commonly used plasticizer, to prepare adhesive sample E, which is used to demonstrate the advantages of the resin of the present application without plasticizer.

[0054] Example 4: Performance testing and characterization

[0055] The basic performance tests of the above prepared resins A, B, C, D are shown in Table 1.

[0056] Test methods:

[0057] Softening point: determined according to GB / T 4507-2014 (ring and ball method).

[0058] Degree of hydrogenation: calculated by the disappearance of olefinic hydrogen through ¹H-NMR.

[0059] Color (Gardner): determined according to GB / T 22295-2008.

[0060] Thermal stability (yellowing index YI): each resin was heated in a blast oven at 180 °C for 72 hours, and its yellowing index (Yellowness Index, YI) was measured after cooling, determined according to ASTM E313.

[0061] Table 1: Comparison table of basic properties of resins

[0062]

[0063] Results analysis:

[0064] 1. As shown in Table 1, the resins A and B prepared by the method of the present application achieved very high hydrogenation degree (>98%) under relatively mild hydrogenation conditions, much higher than the traditional hydrogenated C9 resin D.

[0065] 2. The very high hydrogenation degree brought about excellent initial color and thermal stability. The initial color of resins A and B was water white (Gardner <1), and after 180℃ / 72h thermal aging, the yellow index (YI) was much lower than that of the comparative resin D, proving the excellent thermal oxidation resistance.

[0066] 3. As shown by the comparison of resins A, B and C, resins A and B containing the cationic polymerization step had higher softening point, which indicated that the step effectively increased the molecular weight, thus helping to improve the cohesive strength of the final adhesive.

[0067] Example 4: Preparation and performance test of hot melt pressure sensitive adhesive

[0068] The above resins were used as tackifying resins to prepare environmentally friendly hot melt pressure sensitive adhesive (HMPSA), and their performances were tested. The basic formula of HMPSA (mass parts) was as follows:

[0069] Thermoplastic elastomer: styrene-isoprene-styrene block copolymer (SIS, 1105), 100 parts;

[0070] Tackifying resin: test sample (resin A, B, C, D), 120 parts;

[0071] Plasticizer: none (unless otherwise specified, such as sample E);

[0072] Antioxidant: 1010, 1 part.

[0073] Preparation method: SIS, tackifying resin and antioxidant were added to a melt mixer with heating and stirring function, and melt blended at 160-170℃ for about 1.5 hours until a uniform viscous liquid was formed, discharged and made into standard test sample.

[0074] Test method:

[0075] Tack (Tack): determined according to GB / T 31125-2014 (ball method), the larger the steel ball number, the better the initial tack.

[0076] Holding Power: According to GB / T 4851-2014, the adhesive tape is attached to the standard steel plate, and a 1kg weight is hung at the lower end. The time (minute) for the adhesive tape to fall off at 25℃ is recorded. The longer the time, the higher the cohesive strength.

[0077] Peel Strength: According to GB / T 2792-2014, the peel strength between the adhesive tape and the adherend surface is measured (N / 25mm).

[0078] The test results are shown in Table 2.

[0079] Table 2: Comparison of properties of hot melt pressure-sensitive adhesive

[0080]

[0081] A higher softening point endows the adhesive prepared from the hydrogenated petroleum resin with strong cohesive strength, which is manifested by a holding power higher than 7000 minutes, and can effectively resist creep and damage even under continuous stress conditions, providing a durable and reliable bonding effect. The hydrogenated petroleum resin prepared by the present application has good compatibility with various polymer matrices (such as SIS, SEBS, EVA, etc.), and can form strong interfacial bonding force, and has excellent performance in the application of preparing hot melt adhesive, pressure-sensitive adhesive, tackifier, structural adhesive, etc. Its unique rigid-flexible balanced molecular structure provides high cohesive strength while exhibiting excellent 180° peel strength, ensuring that the adhesive layer can firmly adhere to the substrate and effectively dissipate stress, achieving strong and durable bonding.

[0082] By deep hydrogenation, the hydrogenated petroleum resin prepared by the present application has a highly saturated molecular structure, low color and extremely low yellowing index. The highly saturated structure means that there are few residual unsaturated double bonds and polar substances, and the hydrogenated petroleum resin has excellent chemical stability and extremely low odor, and is particularly suitable for fields with extremely high requirements for purity and safety, such as medical and sanitary products. This feature ensures that the industrial application products (especially light-colored or transparent products) can still maintain a fresh appearance after long-term use, have excellent UV resistance and antioxidant aging resistance, and greatly extend the service life and aesthetic appearance of the products.

[0083] Finally, it should be pointed out that the above preferred embodiments are only used to illustrate the technical solutions of the present application and not to limit it. Although the present application has been described in detail through the above preferred embodiments, those skilled in the art should understand that various changes can be made in form and details without departing from the scope defined by the claims of the present application.

Claims

1. A process for the preparation of D-A reaction based toughened hydrogenated petroleum resin, characterized by, The method comprises the following steps: a. Dissolve the conjugated diene monomer and the dienophile monomer in an organic solvent under an inert gas atmosphere, and distill the D-A addition prepolymer monomer under reduced pressure after reacting at 40-60℃ for 2-6 hours; b. Prepare a solution of 20-50 wt % of the D-A addition prepolymer monomer and dry toluene, cool to -20℃-0℃, start stirring, and introduce inert gas; add a Lewis acid catalyst, and after reacting for 2-4 hours, slowly pour the reaction solution into a vigorously stirred methanol / water mixture, filter the crude resin, and dry to constant weight to obtain a light yellow to amber solid resin; c. Dissolve the solid resin in toluene to form a 10-20 wt % solution, and add a Pd / C noble metal catalyst to a high-pressure autoclave, and perform hydrogenation reaction under a hydrogen gas atmosphere; d. After the reaction is completed, cool, filter, and remove the solvent and low molecular weight substances by distillation under reduced pressure of 2 mmHg-10 mmHg to obtain a water-white hydrogenated petroleum resin.

2. The process for the preparation of hydrogenated petroleum resins according to claim 1, characterized in that, In step a, the proportion of the conjugated diene monomer is 30-55 wt%, and the proportion of the dienophile monomer is 45-70 wt%.

3. The process for the preparation of hydrogenated petroleum resins according to claim 1, characterized in that, The conjugated diene monomer is one of cyclopentadiene, dicyclopentadiene, 1,3-butadiene, and isoprene.

4. The process for the preparation of hydrogenated petroleum resins according to claim 1, characterized in that, The dienophile monomer is one of an acrylic ester, maleic anhydride, and fumarate, wherein the acrylic ester has a molecular formula CH2=CH-COOR, and R is an electron-donating group such as a methyl group or an ethyl group.

5. The process for the preparation of hydrogenated petroleum resins according to claim 1, characterized in that, In step a, the distillation under reduced pressure is performed at 115-125℃ under a pressure of 2 mmHg-10 mmHg.

6. The process for the preparation of hydrogenated petroleum resins according to claim 1, characterized in that, The Lewis acid catalyst is aluminum chloride, boron trifluoride, zinc chloride, or iron trichloride.

7. The process for the preparation of hydrogenated petroleum resins according to claim 1, characterized in that, In step c, the Pd / C noble metal catalyst used has an average particle size of 10-20μm and a Pd content of 5-10 wt%.

8. The process for the preparation of hydrogenated petroleum resins according to claim 1, characterized in that, In step c, the hydrogenation reaction is performed at a temperature of 180-220℃ and a hydrogen pressure of 2.0-5.0 MPa for 4-8 hours.

9. The hydrogenated petroleum resin obtained by the method for preparing the hydrogenated petroleum resin according to any one of claims 1-8.

10. Use of the hydrogenated petroleum resin obtained by the method for preparing the hydrogenated petroleum resin according to any one of claims 1-8 or the hydrogenated petroleum resin according to claim 9 in preparing hot melt adhesives, pressure-sensitive adhesives, tackifiers, and structural adhesives.

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