A method for synthesizing polyester polyol for solvent-resistant rubber roller

Abstract

The present invention belongs to the technical field of polyester polyol preparation, and specifically relates to a method for synthesizing polyester polyol for solvent-resistant rubber rollers. The polyester polyol is prepared from raw materials in parts by weight: 31-40 parts of diols, 53-63 parts of dibasic acids, 4-6 parts of organosilicon compounds, 2.0-2.5 parts of modification aids, 0.1-0.5 parts of modified nanographene, 0.01-0.05 parts of antioxidant aids, and 0.003-0.008 parts of catalysts. The present invention prepares the polyester polyol for solvent-resistant rubber rollers by reasonably selecting and proportioning the raw materials and dosages, and the components cooperate with each other to jointly improve the comprehensive performance of the prepared polyester polyol material, improve its solvent resistance and service life, and the prepared downstream products have good mechanical properties and solvent resistance; at the same time, the viscosity of the prepared polyester polyol is moderate, which is conducive to improving the degassing problem when producing polyurethane printing rubber rollers.

Description

Technical Field

[0001] The invention belongs to the technical field of polyester polyol preparation, and particularly relates to a method for synthesizing polyester polyol for solvent-resistant rubber rollers. Background Art

[0002] The molecular structure of polyurethane elastomer contains a large number of highly polar urethane groups, urea groups, and ester groups, and a large number of hydrogen bonds are easily formed between molecules, so polyurethane elastomer has excellent mechanical properties, aging resistance, and wear resistance. Printing rubber rollers are an important application field of polyurethane elastomers. Since the inks and coatings used in printing contain a large amount of solvents, in this application field, in addition to requiring polyurethane elastomers to have good mechanical strength, wear resistance, and resilience, they must also have excellent solvent resistance.

[0003] The main raw materials for producing polyurethane elastomers are polyisocyanates and polyester polyols or polyether polyols, as well as chain extenders such as small molecule alcohols and small molecule amines. Among these raw materials, polyester polyols have the greatest impact on the solvent resistance of polyurethane elastomers. Therefore, selecting appropriate raw materials and processes to synthesize solvent-resistant polyester polyols has become an important research direction for improving the solvent resistance of printing rubber rollers.

[0004] The most important factor affecting the solvent resistance of polyester polyols is the ester group content in the molecule. In the past, most solvent-resistant polyester polyols were synthesized mainly with adipic acid, ethylene glycol and 1,2-propylene glycol as raw materials. Since the molecular chain of adipic acid is relatively long, the ester group content of the synthesized polyester polyol is relatively low. Therefore, the printing rubber roller made of such polyester polyols and isocyanate has poor solvent resistance. When the roller is coated with a large amount of toluene, xylene, ethyl acetate, cyclohexanone and other solvents or their mixed solvents, it will swell significantly and become brittle in a very short time, resulting in a very short service life of the rubber roller.

[0005] Therefore, it is necessary to provide a polyester polyol that can effectively improve and enhance the solvent resistance of the polyurethane prepared therefrom. Summary of the invention

[0006] In order to solve the problems existing in the prior art, the object of the present invention is to provide a method for synthesizing polyester polyol for solvent-resistant rubber rollers.

[0007] The technical solution of the present invention is:

[0008] A polyester polyol for a solvent-resistant rubber roller comprises the following raw materials in parts by weight:

[0009] 31-40 parts of diol, 53-63 parts of dibasic acid, 4-6 parts of organosilicon compound, 2.0-2.5 parts of modification aid, 0.1-0.5 parts of modified nanographene, 0.01-0.05 parts of antioxidant aid, and 0.003-0.008 parts of catalyst.

[0010] Furthermore, the polyester polyol for solvent-resistant rubber roller is characterized in that it is prepared from the following raw materials in parts by weight:

[0011] 35 parts of diol, 58 parts of dibasic acid, 5 parts of organosilicon compound, 2.2 parts of modification aid, 0.3 parts of modified nanographene, 0.03 parts of antioxidant aid, and 0.005 parts of catalyst.

[0012] Furthermore, the diol is composed of ethylene glycol and 1,3-propylene glycol in a weight ratio of 30-35:1-5, preferably 32:3.

[0013] Furthermore, the dibasic acid is a combination of two or more of succinic acid, adipic acid and isophthalic acid.

[0014] Furthermore, the dibasic acid is composed of succinic acid, adipic acid and isophthalic acid in a weight ratio of 32-35:20-25:1-3, preferably 33:23:2.

[0015] Furthermore, the organic silicon compound is polydimethylsiloxane.

[0016] Furthermore, the polydimethylsiloxane is hydroxyl-terminated polydimethylsiloxane.

[0017] Furthermore, the modification aid is perfluorooctanoic anhydride.

[0018] Furthermore, the antioxidant aid is one of the antioxidants PEPQ, triphenyl phosphite, and poly(dipropylene glycol) phenyl phosphite.

[0019] Furthermore, the catalyst is tetraisopropyl titanate.

[0020] Furthermore, the preparation method of the modified nanographene comprises the following steps:

[0021] (1) 5 g of nanographene was dispersed in a mixture of 100 mL of concentrated nitric acid and concentrated sulfuric acid (volume ratio of 1:3), and then stirred for 2 h using a magnetic stirrer while the temperature was controlled at 50 °C. After the reaction was completed, the product was washed with a large amount of deionized water until the pH value of the washing water was neutral, and the washed product was dried in a vacuum drying oven at 60 °C for 12 h to obtain carboxylated nanographene.

[0022] (2) Dissolve KH550 silane coupling agent (CAS No.: 919-30-2) in ethanol at a concentration of 1% (w / v), then add deionized water, stop adding deionized water when the pH value of the solution reaches 5, and stir for 1 hour to hydrolyze; then disperse the carboxylated nanographene obtained in step (1) in the hydrolyzate of KH550 silane coupling agent, and ultrasonically treat for 30 minutes to ensure uniform dispersion of graphene, the ultrasonic power is 200 W, and the ultrasonic frequency is 35kHz; then, stir and react at 50°C for 5 hours; after the reaction, dry the product in a vacuum drying oven at 60°C for 12 hours to obtain modified nanographene.

[0023] The present invention also provides a method for synthesizing the polyester polyol for solvent-resistant rubber roller, comprising the following steps:

[0024] S1. Add diol and dibasic acid, organosilicon compound and antioxidant additive into a reaction kettle, mix and disperse them evenly, then heat them to remove condensation water, and control the temperature at the top of the distillation tower; then increase the kettle temperature and keep the temperature constant for a period of time, continue to heat the reaction, and use nitrogen as the reaction protection gas;

[0025] S2, after the water is discharged, keep the temperature for 1 to 1.5 hours, add the catalyst and continue to keep the temperature for reaction, then add the modification agent, cool down and stir to react; then add the modified nano-graphene, and heat up and stir;

[0026] S3, then gradually evacuate the system after the reaction in step S2. When the acid value and the hydroxyl value reach the designed values, stop evacuating and cool down to obtain polyester polyol.

[0027] Furthermore, in step S1, when the temperature is heated to 135-140°C, the condensation water begins to be removed, and the temperature at the top of the distillation tower is controlled to be lower than 101°C, and then the kettle temperature is raised to 150-160°C and the reaction is carried out at a constant temperature for 2-3 hours; thereafter, the temperature is gradually raised to 220-225°C at a heating rate of 10-15°C per hour, and when the temperature reaches above 200°C, nitrogen is used as a protective gas.

[0028] Furthermore, in step S2, the insulation temperature before adding the catalyst and the reaction temperature after adding the catalyst are both 220-225° C., and the insulation reaction time after adding the catalyst is 1-2 hours; when adding the modification aid, the temperature is lowered to 190-200° C. and stirred for reaction for 1-2 hours; after adding the modified nano-graphene, the temperature is raised to 230-240° C. and stirring is continued for 1-2 hours.

[0029] Furthermore, the vacuum degree of the vacuum reduction in step S3 is -0.095 to -0.099 MPa, and the vacuum reduction time is 1 to 3 hours.

[0030] Furthermore, the molecular weight of the polyester polyol prepared in step S3 is controlled to be 1420-1540, the acid value is less than 0.8 mgKOH / g, the hydroxyl value is 73-79 mgKOH / g, and the water content is less than 0.03%.

[0031] The raw material for preparing the polyester polyol for solvent-resistant rubber roller provided by the present invention is compared with the prior art. By adjusting the types and proportions of dibasic acids and diols in the raw materials, succinic acid and ethylene glycol are mainly used, and a small amount of adipic acid, 1,3-propylene glycol and isophthalic acid are added. In particular, the proportion of short-chain dibasic acids is increased. The molecular chain of succinic acid is shorter than that of adipic acid. Succinic acid is used to replace a part of adipic acid. The ester group content in the synthesized polyester polyol is significantly increased. The solvent resistance of the polyester polyol is significantly better than that of the polyester polyol synthesized entirely from adipic acid. The service life of the polyurethane printing rubber roller prepared by using the polyol will be significantly increased.

[0032] Furthermore, in addition to the main raw materials such as dibasic acid and diol, a specific amount of organic silicon compound, antioxidant additive, catalyst, modification additive, modified nanographene and other components are added in the present invention. The added organic silicon compound is hydroxyl-terminated polydimethylsiloxane, in which the siloxane segment can increase the steric hindrance between molecules and reduce the interaction between molecules, thereby reducing the viscosity of the obtained polyester polyol and improving the flexibility and chemical resistance of the material; the fluorine group of the added perfluorooctanoic anhydride has extremely high hydrophobicity and oleophobicity, which can enhance the surface properties of the material and make it more solvent-resistant. At the same time, the added modified nanographene can be used as a barrier layer to improve the barrier properties of the material, and can effectively enhance the mechanical properties and thermal stability of the obtained polyester polyol; the added modified nanographene, by introducing polar groups and coupling agent molecules on the surface of nanographene, greatly enhances the compatibility of graphene with polar polymers such as polyester polyols and improves their dispersibility and interface interaction. This enables the modified graphene to be more evenly and stably dispersed in the polymer matrix to form a composite material with excellent performance; the added antioxidant is PEPQ, which can solve the problem of oxidation and yellowing during the synthesis process and improve the color of downstream products. The combination of various components can synergistically improve the overall performance of the prepared polyester polyol.

[0033] Furthermore, according to the synthesis method of the polyester polyol described in the present invention, each component is added to a reaction kettle according to a specific ratio, and an appropriate amount of a stepwise heating method is added to strictly control the reaction temperature and the central control indexes. When the acid value and the hydroxyl value meet the standards, the temperature is reduced and the product is packaged to obtain the polyester polyol.

[0034] In the synthesis process of the present invention, the gradual heating method adopted plays an important role in the preparation process of polyester polyols. By controlling the process steps and parameters in the synthesis method and controlling the temperature at different stages, the reaction process can be accelerated and the reaction rate can be improved. The gradual heating is conducive to the removal of by-products. At the same time, the molecular weight distribution and viscosity can be controlled, the product performance can be improved, the energy can be reasonably used, and the production efficiency can be improved. The prepared polyester polyols have lower viscosity, better solvent resistance and higher mechanical properties.

[0035] Compared with the prior art, the polyester polyol for solvent-resistant rubber roller and the synthesis method provided by the present invention have the following advantages:

[0036] The present invention prepares the various raw materials and dosages of the polyester polyol for solvent-resistant rubber roller by reasonable selection and proportioning, and the various components cooperate with each other to jointly improve the comprehensive performance of the prepared polyester polyol material. The prepared polyester polyol has a narrow molecular weight distribution, and the molecular weight can be controlled at 1420-1540. At the same time, it has a higher ester group content, especially in an environment containing solvents such as toluene, xylene, ethyl acetate, cyclohexanone or their mixed solvents. The solvent resistance and service life are improved, and the prepared downstream products have good mechanical properties and solvent resistance; at the same time, the viscosity of the prepared polyester polyol is moderate, which is conducive to improving the degassing problem when producing polyurethane printing rubber rollers, and effectively improves its performance in practical applications. DETAILED DESCRIPTION

[0037] The present invention is further illustrated below through the description of specific implementation methods, but this is not a limitation of the present invention. Those skilled in the art can make various modifications or improvements based on the basic idea of ​​the present invention, but as long as they do not deviate from the basic idea of ​​the present invention, they are all within the protection scope of the present invention.

[0038] In the following examples and comparative examples, reagents not otherwise specified are conventional reagents and can be purchased from conventional reagent production and sales companies. The methods used, unless otherwise specified, are all existing technologies. Information such as some raw material manufacturers is as follows:

[0039] Hydroxyl-terminated polydimethylsiloxane, CAS number 63148-60-7, purchased from Henan Alpha Chemical Co., Ltd., product number A148607;

[0040] Perfluorooctanoic anhydride, CAS No. 33496-48-9, purchased from Guangdong Wengjiang Chemical Reagent Co., Ltd.;

[0041] Antioxidant PEPQ, CAS No. 119345-01-6, purchased from Hubei Jusheng Technology Co., Ltd.;

[0042] Nanographene, CAS number 1034343-98-0, was purchased from A343980 from Zhengzhou Huiju Chemical Co., Ltd.

[0043] Example 1

[0044] A polyester polyol for a solvent-resistant rubber roller is prepared from the following raw materials in parts by weight:

[0045] 31 parts of diol, 53 parts of dibasic acid, 4 parts of hydroxyl-terminated polydimethylsiloxane, 2.0 parts of perfluorooctanoic anhydride, 0.1 parts of modified nanographene, 0.01 parts of triphenyl phosphite, and 0.003 parts of tetraisopropyl titanate.

[0046] The diol is composed of ethylene glycol and 1,3-propylene glycol in a weight ratio of 30:5.

[0047] The dibasic acid is composed of succinic acid, adipic acid and isophthalic acid in a weight ratio of 32:20:3.

[0048] The preparation method of the modified nano-graphene comprises the following steps:

[0049] (1) 5 g of nanographene was dispersed in a mixture of 100 mL of concentrated nitric acid and concentrated sulfuric acid (volume ratio of 1:3), and then stirred for 2 h using a magnetic stirrer while the temperature was controlled at 50 °C. After the reaction was completed, the product was washed with a large amount of deionized water until the pH value of the washing water was neutral, and the washed product was dried in a vacuum drying oven at 60 °C for 12 h to obtain carboxylated nanographene.

[0050] (2) Dissolve KH550 silane coupling agent (CAS No.: 919-30-2) in ethanol at a concentration of 1% (w / v), then add deionized water, stop adding deionized water when the pH value of the solution reaches 5, and stir for 1 hour to hydrolyze; then disperse the carboxylated nanographene obtained in step (1) in the hydrolyzate of KH550 silane coupling agent, and ultrasonically treat for 30 minutes to ensure uniform dispersion of graphene, the ultrasonic power is 200 W, and the ultrasonic frequency is 35kHz; then, stir and react at 50°C for 5 hours; after the reaction, dry the product in a vacuum drying oven at 60°C for 12 hours to obtain modified nanographene.

[0051] The method for synthesizing the polyester polyol for the solvent-resistant rubber roller comprises the following steps:

[0052] S1. Add diol and dibasic acid, hydroxyl-terminated polydimethylsiloxane and triphenyl phosphite into a reaction kettle, use a high-speed stirrer to mix the raw materials evenly to ensure that the raw materials are evenly dispersed, and then heat them. When the temperature rises to 135°C, condensation water begins to be removed, and the temperature at the top of the distillation tower is controlled to be lower than 101°C; then slowly raise the kettle temperature to 150°C, and react at a constant temperature for 3 hours, and then gradually raise the temperature to 220°C at a heating rate of 10°C per hour. When the temperature reaches above 200°C, nitrogen is used as a protective gas;

[0053] S2. After the water is discharged, continue to keep the temperature at 220°C for 1.5h, add tetraisopropyl titanate, and continue to keep the temperature for 1h; then add perfluorooctanoic anhydride, cool to 190°C, and stir to react for 1h; then add modified nano-graphene, and heat to 230°C, and continue to stir for 1h to ensure that the modified nano-graphene is evenly dispersed;

[0054] S3. Then, the system after the reaction in step S2 is gradually evacuated. When the vacuum degree of the evacuation is -0.095 MPa and the reaction time is 1 h, when the acid value is <0.8 mgKOH / g and the hydroxyl value is 73-79 mgKOH / g, the evacuation is stopped and the temperature is started to be lowered. When the temperature drops below 120°C, re-sampling is performed and all indicators are qualified, and the polyester polyol is packaged to obtain the polyester polyol.

[0055] Example 2

[0056] A polyester polyol for a solvent-resistant rubber roller is prepared from the following raw materials in parts by weight:

[0057] 35 parts of diol, 58 parts of dibasic acid, 5 parts of hydroxyl-terminated polydimethylsiloxane, 2.2 parts of perfluorooctanoic anhydride, 0.3 parts of modified nanographene, 0.03 parts of antioxidant PEPQ, and 0.005 parts of tetraisopropyl titanate.

[0058] The diol is composed of ethylene glycol and 1,3-propylene glycol in a weight ratio of 32:3.

[0059] The dibasic acid is composed of succinic acid, adipic acid and isophthalic acid in a weight ratio of 33:23:2.

[0060] The preparation method of the modified nano-graphene is the same as that in Example 1.

[0061] The method for synthesizing the polyester polyol for the solvent-resistant rubber roller comprises the following steps:

[0062] S1. Add diol and dibasic acid, hydroxyl-terminated polydimethylsiloxane and antioxidant PEPQ into a reactor, use a high-speed stirrer to mix the raw materials evenly to ensure that the raw materials are evenly dispersed, and then heat them. When the temperature rises to 138°C, condensation water begins to be removed, and the temperature at the top of the distillation tower is controlled to be lower than 101°C; then slowly raise the reactor temperature to 155°C, and react at a constant temperature for 2.5 hours, and then gradually raise the temperature to 223°C at a heating rate of 13°C per hour. When the temperature reaches above 200°C, nitrogen is used as a protective gas;

[0063] S2. After the water is discharged, continue to keep the temperature at 223°C for 1.5 hours, add tetraisopropyl titanate, and continue to keep the temperature for 1.5 hours; then add perfluorooctanoic anhydride, cool to 195°C, and stir to react for 1.5 hours; then add modified nano-graphene, and heat to 235°C, and continue to stir for 1.5 hours to ensure that the modified nano-graphene is evenly dispersed;

[0064] S3. Then, the system after the reaction in step S2 is gradually evacuated. When the vacuum degree of the evacuation is -0.097 MPa and the reaction time is 2 h, when the acid value is <0.8 mgKOH / g and the hydroxyl value is 73-79 mgKOH / g, the evacuation is stopped and the temperature is lowered. When the temperature drops below 120° C., re-sampling is performed and all indicators are qualified, and the polyester polyol is packaged to obtain the polyester polyol.

[0065] Example 3

[0066] A polyester polyol for a solvent-resistant rubber roller is prepared from the following raw materials in parts by weight:

[0067] 40 parts of diol, 63 parts of dibasic acid, 6 parts of hydroxyl-terminated polydimethylsiloxane, 2.5 parts of perfluorooctanoic anhydride, 0.5 parts of modified nanographene, 0.05 parts of poly(dipropylene glycol) phenyl phosphite, and 0.008 parts of tetraisopropyl titanate.

[0068] The diol is composed of ethylene glycol and 1,3-propylene glycol in a weight ratio of 35:1.

[0069] The dibasic acid is composed of succinic acid, adipic acid and isophthalic acid in a weight ratio of 35:25:1.

[0070] The preparation method of the modified nano-graphene is the same as that in Example 1.

[0071] The method for synthesizing the polyester polyol for the solvent-resistant rubber roller comprises the following steps:

[0072] S1. Add diol and dibasic acid, hydroxyl-terminated polydimethylsiloxane and poly(dipropylene glycol) phenyl phosphite into a reaction kettle, use a high-speed stirrer to mix the raw materials evenly to ensure that the raw materials are evenly dispersed, and then heat them. When the temperature rises to 140°C, condensation water begins to be removed, and the temperature at the top of the distillation tower is controlled to be lower than 101°C; then slowly raise the kettle temperature to 160°C, and react at a constant temperature for 2h, then gradually raise the temperature to 225°C at a heating rate of 15°C per hour, and start using nitrogen as a protective gas when the temperature reaches above 200°C;

[0073] S2. After the water is discharged, continue to keep the temperature at 225°C for 1 hour, add tetraisopropyl titanate, and continue to keep the temperature for 2 hours; then add perfluorooctanoic anhydride, cool to 200°C, and stir to react for 2 hours; then add modified nano-graphene, and heat to 240°C, and continue to stir for 2 hours to ensure that the modified nano-graphene is evenly dispersed;

[0074] S3. Then, the system after the reaction in step S2 is gradually evacuated. When the vacuum degree of the evacuation is -0.099 MPa and the reaction time is 3 h, when the acid value is <0.8 mgKOH / g and the hydroxyl value is 73-79 mgKOH / g, the evacuation is stopped and the temperature is lowered. When the temperature drops below 120 degrees Celsius, re-sampling is performed and the results are filtered and packaged after all the indicators are qualified to obtain polyester polyol.

[0075] Comparative Example 1

[0076] Compared with Example 2, the difference is that the dibasic acid does not contain succinic acid, that is, the dibasic acid is composed of adipic acid and isophthalic acid in a weight ratio of 56:2, and the other components and preparation method are the same as those in Example 2.

[0077] Comparative Example 2

[0078] Compared with Example 2, the difference is that the dibasic acid does not contain succinic acid and isophthalic acid, that is, the dibasic acid is adipic acid, and the added amount is 58 parts. Other components and preparation methods are the same as those in Example 2.

[0079] Comparative Example 3

[0080] Compared with Example 2, the difference is that no hydroxyl-terminated polydimethylsiloxane is added in step S2, and other components and preparation methods are the same as those in Example 2.

[0081] Comparative Example 4

[0082] Compared with Example 2, the difference is that no perfluorooctanoic anhydride is added in step S3, and the specific steps are as follows:

[0083] S3, after the water is discharged, continue to keep the temperature at 223 ° C for 1 hour, add tetraisopropyl titanate, and continue to keep the temperature for 1.5 hours; then add modified nano-graphene, and heat to 235 ° C, continue to stir for 1.5 hours to ensure that the modified nano-graphene is evenly dispersed. Other components and preparation methods are the same as those in Example 2.

[0084] Comparative Example 5

[0085] Compared with Example 2, the difference is that in S3, the perfluorooctanoic anhydride and the modified nano-graphene in step S3 are added to the reactor at the same time for reaction, and the specific steps are as follows:

[0086] S3, after the water is discharged, continue to keep the temperature at 223 ° C for 1 hour, add tetraisopropyl titanate, and continue to keep the temperature for 1.5 hours; then add perfluorooctanoic anhydride and modified nanographene, and heat to 235 ° C, continue to stir for 2 hours to ensure that the modified nanographene is evenly dispersed. Other components and preparation methods are the same as those in Example 2.

[0087] Test Example 1: Performance index detection of polyester polyol for solvent-resistant rubber roller prepared by the present invention

[0088] The hydroxyl value (mg KOH / g), acid value (mg KOH / g), water content (%), viscosity (mPa·s) and molecular weight of the polyester polyols of the solvent-resistant rubber rollers prepared in Examples 1 to 3 and Comparative Examples 1 to 5 of the present invention were tested respectively, and the results are shown in Table 1.

[0089] Table 1

[0090] Group Hydroxyl value (mg KOH / g) Acid value (mg KOH / g) Water content (%) Viscosity (mPa·s) Example 1 79 0.37 0.02 2600 Example 2 73 0.33 0.01 2500 Example 3 75 0.41 0.01 2500 Comparative Example 1 98 0.46 0.01 2900 Comparative Example 2 93 0.53 0.02 2800 Comparative Example 3 82 0.43 0.01 3600 Comparative Example 4 77 0.38 0.01 2700 Comparative Example 5 75 0.46 0.02 2600

[0091] As shown in Table 1, the polyester polyols for solvent-resistant rubber rollers prepared by using the raw materials and synthesis methods of Examples 1 to 3 of the present invention have an acid value of less than 0.8 mgKOH / g, a hydroxyl value of 73 to 79 mgKOH / g, a water content of less than 0.03%, a moderate viscosity, and comprehensive indicators that are better than the polyester polyols prepared by Comparative Examples 1 to 5, indicating that the use of the raw materials and synthesis methods provided by the present invention can jointly improve the comprehensive performance of the prepared polyester polyols. At the same time, the prepared polyester polyols have a moderate viscosity, which is beneficial to improving the degassing problem in the production of polyurethane printing rubber rollers.

[0092] Test Example 2: Application Performance Test of the Polyester Polyol Prepared by the Present Invention

[0093] The polyester polyols prepared in Example 2 and Comparative Examples 1 to 5 were used as raw materials, respectively, and a polyurethane elastomer was prepared by a prepolymerization method, including the following components in weight percentage:

[0094] Example 2, Comparative Examples 1 to 5: 85% of the polyester polyol and 15% of 2,4-diisocyanatotoluene (TDI-100) were reacted at 85° C. for 3 hours under nitrogen protection to obtain a prepolymer with an NCO content of 3.5-4.5%. 20% of the weight of trioctyl trimellitate was added to the obtained prepolymer, and then trimethylolpropane was added at 85° C. (the weight ratio of the prepolymer to the trimethylolpropane was 100:5) and stirred evenly. The mixture was poured into a mold, placed in an oven at 110° C. for 15 hours, taken out of the mold, and then placed in an oven at 90° C. for aging for 12 hours to obtain a solvent-resistant polyurethane elastomer sample with a hardness of 30 to 60 shore A.

[0095] The prepared sample can be used for testing after being placed at room temperature for 72 hours.

[0096] The hardness (Shore A), elongation at break (%), tensile strength (MPa) and solvent resistance of the solvent-resistant polyurethane elastomers prepared in Example 2 and Comparative Examples 1 to 5 were tested respectively.

[0097] The solvent resistance detection method is as follows: take the polyurethane elastomer prepared in each group, record the initial mass, then soak in toluene, ethyl acetate, and cyclohexanone for 24 hours at a soaking temperature of 25°C, record the mass after soaking, and calculate the weight increase percentage (%) of the polyurethane elastomer samples prepared in each group in different organic solvents. The results are shown in Table 2.

[0098] Table 2

[0099]

[0100] As can be seen from Table 2, the polyurethane elastomer prepared using the polyester polyol prepared in Example 2 of the present invention as a raw material has suitable elongation at break and tensile strength, and can also improve its solvent resistance and service life, especially in an environment containing solvents such as toluene, xylene, ethyl acetate, cyclohexanone or their mixed solvents, and effectively improves its performance in practical applications.

[0101] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical ideas disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A polyester polyol for a solvent-resistant rubber roller, characterized in that: The invention comprises the following raw materials in parts by weight: 31-40 parts of diol, 53-63 parts of dibasic acid, 4-6 parts of organosilicon compound, 2.0-2.5 parts of modification aid, 0.1-0.5 parts of modified nanographene, 0.01-0.05 parts of antioxidant aid, 0.003-0.008 parts of catalyst; The diol is composed of ethylene glycol and 1,3-propylene glycol in a weight ratio of 30-35:1-5; The dibasic acid is composed of succinic acid, adipic acid and isophthalic acid in a weight ratio of 32-35:20-25:1-3; The organosilicon compound is polydimethylsiloxane siloxane; the modification aid is perfluorooctanoic anhydride; The method for preparing the polyester polyol for the solvent-resistant rubber roller comprises the following preparation steps: S1. Add diol and dibasic acid, organosilicon compound and antioxidant additive into a reaction kettle, mix and disperse them evenly, then heat them to remove condensation water, and control the temperature at the top of the distillation tower; then increase the kettle temperature and keep the temperature constant for a period of time, continue to heat the reaction, and use nitrogen as the reaction protection gas; S2, after the water is discharged, keep the temperature for 1-1.5 h, add the catalyst and continue to keep the temperature for reaction, then add the modification agent, cool down and stir to react; then add the modified nano-graphene, and heat up and stir; S3, then gradually evacuate the system after the reaction in step S2, and when the acid value and the hydroxyl value reach the designed values, stop evacuating and cool down to obtain polyester polyol; In the step S2, the insulation temperature before adding the catalyst and the reaction temperature after adding the catalyst are both 220-225° C., and the insulation reaction time after adding the catalyst is 1-2 h; when adding the modification aid, the temperature is lowered to 190-200° C. and stirred for reaction for 1-2 h; after adding the modified nano-graphene, the temperature is raised to 230-240° C. and stirring is continued for 1-2 h.

2. The polyester polyol for solvent-resistant rubber roller according to claim 1, characterized in that: It is prepared from the following raw materials in parts by weight: 35 parts of diol, 58 parts of dibasic acid, 5 parts of organosilicon compound, 2.2 parts of modification aid, 0.3 parts of modified nanographene, 0.03 parts of antioxidant aid, and 0.005 parts of catalyst.

3. The polyester polyol for solvent-resistant rubber roller according to claim 1 or 2, characterized in that: The antioxidant aid is one of antioxidant PEPQ, triphenyl phosphite and poly(dipropylene glycol) phenyl phosphite; and the catalyst is tetraisopropyl titanate.

4. The polyester polyol for solvent-resistant rubber roller according to claim 1 or 2, characterized in that: In the step S1, when the temperature is heated to 135-140°C, the condensation water is removed, and the temperature at the top of the distillation tower is controlled to be lower than 101°C, and then the kettle temperature is raised to 150-160°C and the reaction is carried out at a constant temperature for 2-3 hours; thereafter, the temperature is gradually raised to 220-225°C at a heating rate of 10-15°C per hour, and when the temperature reaches above 200°C, nitrogen is used as a protective gas.

5. The polyester polyol for solvent-resistant rubber roller according to claim 1 or 2, characterized in that: The vacuum degree of the vacuum reduction in step S3 is -0.095 to -0.099 MPa, and the vacuum reduction time is 1 to 3 h; the acid value is less than 0.8 mgKOH / g, and the hydroxyl value is 73 to 79 mgKOH / g.

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