A process for the preparation of a high softening point isoprene petroleum resin

Abstract

A preparation method of high softening point isoprene petroleum resin, comprising the following steps: step one, uniformly mixing concentrated isoprene, part of solvent and monoolefin according to proportion to obtain reactant; step two, adding the remaining solvent into a reaction kettle, heating to 75-85 DEG C under stirring, adding catalyst to react, then adding the reactant of step one at a speed of 45-50 g / min to react, controlling the temperature in the reaction kettle at 75-85 DEG C during the feeding process; step three, after the reactant is added completely, continuing to react for 20-30 min under the condition of reaction temperature 75-85 DEG C, then cooling to 20-30 DEG C by opening cooling water to discharge to obtain reaction liquid, carrying out post-treatment on the reaction liquid to obtain isoprene petroleum resin product. The present application can improve the softening point of C5 petroleum resin without introducing heterogeneous monomer, and reduce the cost, avoid the color deepening of the resin and the heavier odor.

Description

Technical Field

[0001] This invention belongs to the field of polymer synthesis technology, specifically relating to a method for preparing a high softening point isoprene petroleum resin. Background Technology

[0002] Isoprene petroleum resin is one of the core categories of C5 petroleum resins. Due to its light color, good tackifying effect, moderate softening point, and good compatibility with a variety of polymers, it is widely used in hot melt adhesives, pressure-sensitive adhesives, coatings, rubber tackifying and other fields.

[0003] Currently, C5 petroleum resins are typically produced using concentrated isoprene, C5 monoolefins, and saturated hydrocarbons as raw materials. These are then subjected to cationic copolymerization using Lewis acid catalysts (such as aluminum trichloride and boron trifluoride). The polymerized product is then washed with water to remove the catalyst, flash-evaporated to remove the solvent, and stripped to remove oligomers, yielding the final product, isoprene petroleum resin. The softening point of this product is generally between 85 and 100°C. However, with the increasing demands for heat resistance in BOPP films and high-temperature hot melt adhesives, the need for C5 petroleum resins with a softening point ≥120°C is becoming increasingly urgent.

[0004] To address the issue of the low softening point of C5 petroleum resin, existing technologies generally involve adding rigid copolymers to the polymerization formulation. For example, the process disclosed in Chinese invention patent No. ZL201110043336.2, "A Method for Preparing a High Softening Point Petroleum Resin" (authorization announcement No. CN102643389B), involves introducing 10%–50% rigid comonomers (dicyclopentadiene, C9 fraction, styrene, α-methylstyrene, indene, etc.) into the C5 fraction, using anhydrous aluminum trichloride as an initiator to prepare a high softening point petroleum resin with a softening point of 125–150°C. For example, the process disclosed in Chinese invention patent No. ZL202211492868.9, "A method for preparing C5 petroleum resin" (authorization announcement No. CN115725021B), uses concentrated isoprene, isopentenene (C5 monoolefin), dicyclopentadiene, α-pinene, and styrene monomers as raw materials, and adopts Lewis acid catalysis and stepwise cationic polymerization process to prepare C5 petroleum resin with a softening point of 110-120℃.

[0005] The above technical solutions have the following main drawbacks: 1) Introducing C9 fraction or dicyclopentadiene to increase the softening point will deepen the resin color, affecting its application in light-colored or transparent products; 2) α-pinene is expensive, and introducing α-pinene will increase production costs; 3) C9 fraction and dicyclopentadiene have strong odors, and resins prepared by introducing C9 fraction or dicyclopentadiene are not suitable for applications such as food packaging that have strict requirements for odor.

[0006] Therefore, it is important to develop a method to increase the softening point of C5 petroleum resin without introducing heterogeneous monomers. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to provide a method for preparing high softening point isoprene petroleum resin in view of the current state of the prior art, so as to improve the softening point of C5 petroleum resin without introducing heterogeneous monomers, and reduce costs, avoid resin color darkening and strong odor.

[0008] The technical solution adopted by this invention to solve the above-mentioned technical problems is: a method for preparing a high softening point resorcinol petroleum resin, characterized by comprising the following steps:

[0009] Step 1: Mix concentrated isoprene, a portion of the solvent, and mono-olefin in a specific ratio to obtain the reaction mixture.

[0010] Step 2: Add the remaining solvent into the reactor and heat it to 75℃~85℃ while stirring. Then add the catalyst to react. Next, add the reactants from Step 1 at a rate of 45g / min~50g / min to react. During the addition process, control the temperature inside the reactor at 75℃~85℃.

[0011] Step 3: After all the reactants have been added, continue the reaction at a temperature of 75℃~85℃ for 20min~30min, then cool down to 20℃~30℃ and discharge the material to obtain the reaction solution. The reaction solution is then post-processed to obtain the isoprene petroleum resin product.

[0012] In this embodiment, by weight, the amount of concentrated isoprene is 4.2 to 4.9 parts, the amount of mono-olefin is 1.6 to 2.0 parts, and the mono-olefin is 2-methyl-2-butene, the amount of catalyst is 0.03 to 0.05 parts, and the catalyst is a Lewis acid, the total amount of solvent is 3.1 to 4.0 parts, and the ratio of the amount of solvent in step one to the amount of solvent remaining in step two is 1.2 to 2.3:4, and the solvent is a mixture of cycloalkanes and straight-chain alkanes.

[0013] Preferably, the purity of the 2-methyl-2-butene is 93.5%.

[0014] Preferably, the catalyst is aluminum trichloride.

[0015] Preferably, the solvent is a polymerization reaction cycle solvent, and its main components are at least one of cyclopentane, n-pentane, and isopentane.

[0016] Preferably, the concentration of the concentrated isoprene is 65wt% to 70wt%.

[0017] Preferably, in step two, the temperature inside the reactor is higher than 75°C.

[0018] In the above schemes, preferably, the method for post-treating the reaction solution in step three is as follows:

[0019] Pure water and defoamer are added to the reaction solution. The temperature of the pure water is 50℃~60℃ and the pure water accounts for 8%~15% of the weight of the reaction solution to dissolve the catalyst and prevent the reaction solution from foaming. Then, the water containing the catalyst is separated from the reaction solution using a separatory funnel. After separation, the reaction solution is desolventized by flash evaporation and stripped to remove oligomers to obtain isoprene petroleum resin product.

[0020] Preferably, the softening point of the isoprene petroleum resin product is 120°C to 125°C.

[0021] Preferably, the molecular weight Mz of the isoprene petroleum resin product is 0.6 to 0.7 million.

[0022] Preferably, the Gardner color number of the isoprene petroleum resin product is lower than 3.5.

[0023] Compared with the prior art, the advantages of the present invention are as follows: The C5 petroleum resin prepared by the present invention uses concentrated isoprene, 2-methyl-2-butene and recycled solvent as raw materials and Lewis acid (such as aluminum trichloride) as catalyst. Under the premise of appropriately increasing the polymerization temperature, the softening point of the product can be increased, while overcoming the defects of the prior art such as increased production cost, darker resin color and increased odor.

[0024] In this invention:

[0025] 1) The C5 monoolefin in the polymerization formulation is changed from ordinary mixed monoolefins (1-pentene, 2-pentene, cyclopentene and isopentene, etc.) to 2-methyl-2-butene. The significant steric hindrance effect of the trisubstituted double bond of 2-methyl-2-butene and its high activity in cationic polymerization are utilized to enhance the rigidity of the polymer chain segments, thereby increasing the softening point of C5 petroleum resin without introducing any heterogeneous monomers.

[0026] 2) Appropriately increasing the polymerization temperature to 75℃~85℃ increases intermolecular cyclization. Cationic polymerization of isoprene can undergo intramolecular cyclization, increasing the rigidity of the resulting polymer chain segments and raising the softening point.

[0027] 3) In the cationic polymerization process, the C5 monoolefins that do not participate in the polymerization reaction exist as chain transfer agents, making the molecular weight of the product controllable during the polymerization process. In this invention, after replacing the low-activity common mixed monoolefins with the highly active 2-methyl-2-butene, the chain transfer agent in the system is reduced. At this time, in order to make the molecular weight of the product controllable during the polymerization process, this invention increases the reaction temperature to increase the activity of the chain transfer agent in the system, thereby effectively controlling the molecular weight of the product.

[0028] This invention increases the polymerization temperature to 75℃~85℃ and changes the C5 monoolefin in the polymerization formula from ordinary mixed monoolefins (1-pentene, 2-pentene, cyclopentene and isopentene, etc.) to 2-methyl-2-butene. This effectively increases the softening point of C5 petroleum resin without introducing heterogeneous monomers, and the molecular weight of the product is controllable.

[0029] Through the above adjustments, the softening point of isoprene petroleum resin can be increased to above 120℃, while maintaining excellent properties such as light resin color (Gardner color number ≤3.0), low odor, and moderate molecular weight without increasing production costs, thus meeting the requirements of high-performance applications such as high-temperature hot melt adhesives. Detailed Implementation

[0030] Example 1:

[0031] A method for preparing a high softening point isoprene petroleum resin, comprising the following steps:

[0032] Add 134g of circulating solvent, 800g of concentrated isoprene, and 316g of 2-methyl-2-butene to the raw material tank, mix well to obtain the reaction material, and set aside for use.

[0033] Add 400g of circulating solvent to a 5L reactor, start stirring, and raise the temperature. When the reactor temperature reaches 80℃, add 6.6g of aluminum trichloride catalyst, immediately start the feed pump, and add the reactants from the raw material tank into the reactor. Control the feed rate at about 45g / min. Throughout the reaction process, maintain the reaction temperature at 80℃.

[0034] After all the materials in the raw material tank have been added, continue the reaction at a controlled temperature of 80℃ for another 30 minutes.

[0035] After the reaction is complete, the material is discharged and subjected to water washing to remove the catalyst, flash evaporation to remove the solvent, and stripping to remove the oligomers to obtain the isoprene petroleum resin product. Specifically, pure water and defoamer are added to the reaction solution. The temperature of the pure water is 50℃~60℃, and the pure water accounts for 8%~15% of the weight of the reaction solution to dissolve the catalyst and prevent the reaction solution from foaming. Then, the water containing the catalyst is separated from the reaction solution using a separatory funnel. After separation, the reaction solution is subjected to flash evaporation to remove the solvent and stripping to remove the oligomers to obtain the isoprene petroleum resin product. The same applies below.

[0036] According to gel permeation chromatography, the molecular weight (Mz) of the isoprene petroleum resin product is 0.69 million; according to the softening point tester, the softening point of the isoprene petroleum resin product is 124℃; according to the yellow index tester, the Gardner color number of the isoprene petroleum resin product is 2.8.

[0037] Example 2:

[0038] A method for preparing a high softening point isoprene petroleum resin, comprising the following steps:

[0039] Add 257g of circulating solvent, 700g of concentrated isoprene, and 293g of 2-methyl-2-butene to the raw material tank, mix well to obtain the reaction material, and set aside for use.

[0040] Add 400g of circulating solvent to a 5L reactor, start stirring, and raise the temperature. When the reactor temperature reaches 80℃, add 6.6g of aluminum trichloride catalyst, immediately start the feed pump, and add the reactants from the raw material tank into the reactor. Control the feed rate at about 45g / min. Throughout the reaction process, maintain the reaction temperature at 80℃.

[0041] After all the materials in the raw material tank have been added, continue the reaction at 80℃ for another 30 minutes. After the reaction is complete, discharge the material, wash away the catalyst with water, remove the solvent by flash evaporation, and strip away the oligomers to obtain the isoprene petroleum resin product.

[0042] According to gel permeation chromatography, the molecular weight (Mz) of the isoprene petroleum resin product is 0.65 million; according to the softening point tester, the softening point of the isoprene petroleum resin product is 120℃; according to the yellow index tester, the Gardner color number of the isoprene petroleum resin product is 2.7.

[0043] Example 3:

[0044] A method for preparing a high softening point isoprene petroleum resin, comprising the following steps:

[0045] Add 260g of circulating solvent, 710g of concentrated isoprene, and 280g of 2-methyl-2-butene to the raw material tank, mix well to obtain the reaction material, and set aside for use.

[0046] Add 400g of circulating solvent to a 5L reactor, start stirring, and raise the temperature. When the reactor temperature reaches 70℃, add 8.25g of aluminum trichloride catalyst, immediately start the feed pump, and add the reactants from the raw material tank into the reactor. Control the feed rate at about 50g / min. Throughout the reaction process, maintain the reaction temperature at 70℃.

[0047] After all the materials in the raw material tank have been added, continue the reaction at a controlled temperature of 70°C for another 30 minutes. After the reaction is complete, discharge the material, wash away the catalyst with water, remove the solvent by flash evaporation, and strip away the oligomers to obtain the isoprene petroleum resin product.

[0048] According to gel permeation chromatography, the molecular weight (Mz) of the isoprene petroleum resin product is 0.69 million; according to the softening point tester, the softening point of the isoprene petroleum resin product is 122℃; according to the yellow index tester, the Gardner color number of the isoprene petroleum resin product is 2.7.

[0049] Example 4:

[0050] A method for preparing a high softening point isoprene petroleum resin, comprising the following steps:

[0051] Add 130g of circulating solvent, 790g of concentrated isoprene, and 330g of 2-methyl-2-butene to the raw material tank, mix well to obtain the reaction material, and set aside for use.

[0052] Add 400g of circulating solvent to a 5L reactor, start stirring, and raise the temperature. When the reactor temperature reaches 85℃, add 5.5g of aluminum trichloride catalyst, immediately start the feed pump, and add the reactants from the raw material tank into the reactor. Control the feed rate at about 48g / min. Throughout the reaction process, maintain the reaction temperature at 85℃.

[0053] After all the materials in the raw material tank have been added, continue the reaction at a controlled temperature of 85℃ for another 30 minutes. After the reaction is complete, discharge the material, and after washing away the catalyst with water, flash evaporation to remove the solvent, and stripping to remove the oligomers, obtain the isoprene petroleum resin product.

[0054] According to gel permeation chromatography, the molecular weight (Mz) of the isoprene petroleum resin product is 0.64 million; according to the softening point tester, the softening point of the isoprene petroleum resin product is 122℃; according to the yellow index tester, the Gardner color number of the isoprene petroleum resin product is 2.8.

[0055] Comparative Example 1:

[0056] This comparative example is basically the same as Example 1, except that the 2-methyl-2-butene in Example 1 is replaced with an equal amount of C5 monoolefin (the monoolefin obtained by the C5 separation device, whose main components are 1-pentene, 2-pentene, cyclopentene and isopentenene, etc.).

[0057] According to gel permeation chromatography, the molecular weight (Mz) of the isoprene petroleum resin product prepared in this comparative example is 0.67 million; according to the softening point tester, the softening point of the isoprene petroleum resin product prepared in this comparative example is 113℃; according to the yellow index tester, the Gardner color number of the isoprene petroleum resin product prepared in this comparative example is 2.8.

[0058] Therefore, under the same process conditions, replacing C5 monoolefins with 2-methyl-2-butene can increase the resin softening point by about 11°C.

[0059] Comparative Example 2:

[0060] This comparative example is basically the same as Example 1, except that the 2-methyl-2-butene in Example 1 is replaced with an equal amount of C9 fraction (the main components are dicyclopentadiene, methylstyrene, indene, etc.).

[0061] According to gel permeation chromatography, the molecular weight (Mz) of the isoprene petroleum resin product prepared in this comparative example is 0.85 million; according to the softening point tester, the softening point of the isoprene petroleum resin product prepared in this comparative example is 121℃; according to the yellow index tester, the Gardner color number of the isoprene petroleum resin product prepared in this comparative example is 3.5.

[0062] Therefore, under the same process conditions, replacing the C9 fraction with 2-methyl-2-butene can reduce the Gardner color number of the resin by 0.7.

[0063] Comparative Example 3:

[0064] This comparative example is basically the same as Example 2, except that the reaction temperature in this comparative example is 55°C (the reaction temperature in Example 2 is 80°C).

[0065] According to gel permeation chromatography, the molecular weight (Mz) of the isoprene petroleum resin product prepared in this comparative example is 0.80 million; according to the softening point tester, the softening point of the isoprene petroleum resin product prepared in this comparative example is 112℃; according to the yellow index tester, the Gardner color number of the isoprene petroleum resin product prepared in this comparative example is 2.7.

[0066] Therefore, it can be seen that, with the same raw material composition and catalyst dosage, increasing the reaction temperature can raise the softening point of the product and reduce its molecular weight.

Claims

1. A method for preparing a high softening point isoprene petroleum resin, characterized in that... Includes the following steps: Step 1: Mix concentrated isoprene, a portion of the solvent, and mono-olefin in a specific ratio to obtain the reaction mixture. Step 2: Add the remaining solvent into the reactor and heat it to 75℃~85℃ while stirring. Then add the catalyst to react. Next, add the reactants from Step 1 at a rate of 45g / min~50g / min to react. During the addition process, control the temperature inside the reactor at 75℃~85℃. Step 3: After all the reactants have been added, continue the reaction at a temperature of 75℃~85℃ for 20min~30min, then cool down to 20℃~30℃ and discharge the material to obtain the reaction solution. The reaction solution is then post-processed to obtain the isoprene petroleum resin product. In this embodiment, by weight, the amount of concentrated isoprene is 4.2 to 4.9 parts, the amount of mono-olefin is 1.6 to 2.0 parts, and the mono-olefin is 2-methyl-2-butene, the amount of catalyst is 0.03 to 0.05 parts, and the catalyst is a Lewis acid, the total amount of solvent is 3.1 to 4.0 parts, and the ratio of the amount of solvent in step one to the amount of solvent remaining in step two is 1.2 to 2.3:4, and the solvent is a mixture of cycloalkanes and straight-chain alkanes.

2. The preparation method according to claim 1, characterized in that: The purity of the 2-methyl-2-butene is 93.5%.

3. The preparation method according to claim 1, characterized in that: The catalyst is aluminum trichloride.

4. The preparation method according to claim 1, characterized in that: The solvent is a circulating solvent for the polymerization reaction, and its main components are at least one of cyclopentane, n-pentane, and isopentane.

5. The preparation method according to claim 1, characterized in that: The concentration of the concentrated isoprene is 65wt%~70wt%.

6. The preparation method according to claim 1, characterized in that: In step two, the temperature inside the reactor is above 75°C.

7. The preparation method according to any one of claims 1 to 6, characterized in that: The method for post-processing the reaction solution in step three is as follows: Pure water and defoamer are added to the reaction solution. The temperature of the pure water is 50℃~60℃ and the pure water accounts for 8%~15% of the weight of the reaction solution to dissolve the catalyst and prevent the reaction solution from foaming. Then, the water containing the catalyst is separated from the reaction solution using a separatory funnel. After separation, the reaction solution is desolventized by flash evaporation and stripped to remove oligomers to obtain isoprene petroleum resin product.

8. The preparation method according to claim 7, characterized in that: The softening point of the isoprene petroleum resin product is 120℃~125℃.

9. The preparation method according to claim 7, characterized in that: The molecular weight (Mz) of the isoprene petroleum resin product is 0.6 to 0.7 million.

10. The preparation method according to claim 7, characterized in that: The Gardner color number of the isoprene petroleum resin product is less than 3.5.