A bio-based polyol and its preparation method and application

Abstract

The present invention belongs to the field of chemical materials and production technology, and relates to a bio-based polyol and a preparation method and application thereof. Epoxy vegetable oil is subjected to a first ring-opening reaction with an acidic catalyst and a first ring-opening reagent to obtain a first reaction liquid; the first reaction liquid is then subjected to a second ring-opening reaction with a second ring-opening reagent to obtain a reaction liquid containing a bio-based polyol; wherein the first ring-opening reagent is erythritol; and the second ring-opening reagent is lactose. The present invention uses two specific types of ring-opening reagents to react in series to obtain a small amount of epoxy value residue, and the prepared vegetable oil polyol has a novel structure, and the hydroxyl value of the polyol is moderate and evenly distributed, and can replace traditional petrochemical polyols. The vegetable oil polyol prepared by the present invention is used to prepare polyurethane rigid foam materials, and the performance is significantly improved.

Description

Technical Field

[0001] The invention belongs to the technical field of chemical materials and production thereof, and relates to a bio-based polyol and a preparation method and application thereof. Background Art

[0002] Polyurethane is a polymer with repeating structural units of carbamate segments made by the reaction of isocyanate and polyol. Polyurethane products are divided into two categories: foamed products and non-foamed products. Foamed products include soft, hard, and semi-hard polyurethane foam plastics; non-foamed products include coatings, adhesives, synthetic leather, soft foams, and elastic fibers.

[0003] Traditional polyether polyols use polyols such as glycerol, diethylene glycol, propylene glycol as initiators, and propylene oxide and ethylene oxide as chain extenders, and contain more than 98% petroleum derivatives. At present, people hope to reduce dependence on petroleum and improve the environment. Compared with petroleum polyols, biomass polyols reduce energy consumption by 23%, non-renewable resource consumption by 61%, and greenhouse gas emissions by 36%. Replacing petroleum-based polyols with them to produce polyurethane has become an important direction for the development of polyurethane materials. Soybean oil, as the cheapest and most abundant vegetable oil, can be used for polyurethane synthesis by molecular modification to make soybean oil-based polyols. The polyurethane products produced in this way are not only safe and hygienic, but also show better mechanical properties, thermal stability and chemical resistance. The development of vegetable oil polyols is considered to be an effective way to develop bio-based materials. As an important monomer of bio-based polyurethane materials, it is derived from vegetable oil as raw material through chemical modification of molecular structure. It is an important renewable resource. It reacts with isocyanate compounds to produce polyurethane. It has potential applications in many fields and is a good substitute for petroleum-based polyols.

[0004] The long-chain groups in the vegetable oil structure replace the repeating units of traditional petrochemical polyol polyethers or polyesters. The basic mother nucleus of triglycerides in the structure has a star-shaped spatial conformation, which gives downstream polyurethane more functional properties and application space. However, vegetable oil polyols often have performance defects. The main reason is that the reaction process is uncontrollable. During the functional group conversion process, multiple epoxy groups and ester groups often participate in multiple side reaction processes, which makes it difficult to construct the designed molecular structure through traditional chemical methods, greatly limiting the quality of polyols. It often needs to be mixed with traditional petrochemical polyols to have a certain application effect. Through the analysis of the reaction mechanism, the main reason is that oil esters often have poor miscibility with reaction reagents, but low reaction activity, resulting in long-term high-intensity reaction. However, the influence of multiple functional groups in the structure makes it difficult to balance the reaction selectivity and conversion rate, and the process controllability is poor, resulting in poor molecular uniformity of the obtained product, high viscosity, and large differences in macroscopic indicators and microscopic indicators of a single molecule. Therefore, even though the price of vegetable oil is often lower than the monomer price of petrochemical repeating units, it is difficult to obtain vegetable oil polyol products with advantages in both cost and quality. It is necessary to control product quality through chemical process control. In this reaction system, the use of micro-reaction technology to intensify the chemical reaction process and continuously and precisely control it is an effective solution.

[0005] Generally speaking, polyurethane products formed by polyester polyols are superior to those formed by polyether polyols in terms of mechanical strength. The possible reason is the potential effect of hydrogen bonds formed between the ester group in the polyol and the amine in the isocyanate. At present, the quality control of polyol products can only be carried out through reaction process control and macro-indicator regulation, as the components of vegetable oils are not single and the structure-activity relationship is unclear. Therefore, controlling the uniformity of products through process control as much as possible is important for the development of new polyol products and downstream applications. Summary of the invention

[0006] The technical problem to be solved by the present invention is to provide a bio-based polyol and a preparation method and application thereof in view of the deficiencies in the prior art.

[0007] Invention idea: In order to optimize the mechanical properties of downstream products of polyester polyols, erythritol derived from biomass and having multiple hydroxyls is used as the first ring-opening reagent, and the ring-opening reaction of some epoxy groups is completed through process control, and then lactose containing multiple hydroxyls and a rigid structure is used to carry out a ring-opening reaction on the residual epoxy groups to obtain a bio-based polyol product with a small amount of residual epoxy value. In order to avoid the cross-linking side reaction caused by the non-selective ring opening of secondary hydroxyl groups and other epoxy groups during the ring-opening reaction, the present invention adopts micro-reaction technology and selects a microchannel reaction device as the reaction equipment to further control the ring-opening groups.

[0008] In order to solve the above technical problems, the technical solution adopted by the present invention is as follows:

[0009] The invention discloses a method for preparing a bio-based polyol. The method comprises: performing a first ring-opening reaction on an epoxidized vegetable oil, an acidic catalyst and a first ring-opening reagent to obtain a first reaction liquid. The first reaction liquid is then subjected to a second ring-opening reaction on a second ring-opening reagent to obtain a reaction liquid containing the bio-based polyol.

[0010] Wherein, the first ring-opening reagent is erythritol; the second ring-opening reagent is lactose;

[0011] The first ring-opening reaction and the second ring-opening reaction are carried out in a microchannel reaction device.

[0012] In some embodiments, the epoxidized vegetable oil is any one or a combination of epoxidized olive oil, epoxidized peanut oil, epoxidized rapeseed oil, epoxidized cottonseed oil, epoxidized soybean oil, epoxidized coconut oil, epoxidized palm oil, epoxidized sesame oil, epoxidized corn oil and epoxidized sunflower oil; the acidic catalyst is any one or a combination of fluoroboric acid, phosphoric acid, phosphotungstic acid and lipase CALB.

[0013] In some embodiments, preferably, the epoxidized vegetable oil is epoxidized soybean oil; the acidic catalyst is fluoroboric acid; wherein the fluoroboric acid is in the form of an aqueous solution, and the concentration of the fluoroboric acid in the solution is 40 wt.% to 50 wt.%.

[0014] In some embodiments, the mass ratio of the epoxidized vegetable oil to the acidic catalyst is 1:0.02%~0.10%; the molar ratio of the epoxy group in the epoxidized vegetable oil to the first ring-opening reagent is 1:0.6~0.8; and the reaction temperature of the first ring-opening reaction is 40~80°C.

[0015] In some embodiments, preferably, the mass ratio of the epoxidized vegetable oil to the acidic catalyst is 1: 0.06%~0.10%, and more preferably 0.08%; the molar ratio of the epoxy group in the epoxidized vegetable oil to the first ring-opening reagent is 1: 0.6~0.7; the reaction temperature of the first ring-opening reaction is 50~70°C, and more preferably 60°C.

[0016] In some embodiments, the first ring-opening reaction is carried out in a first solvent, and the first solvent is any one or a combination of water, ethanol, propylene glycol, methanol, pyridine and 1-propanol; the mass volume ratio of the first ring-opening reagent to the first solvent is 1 g: 0.5 mL~2 mL.

[0017] In some embodiments, preferably, the first ring-opening reaction is carried out in a first solvent, and the first solvent is water; the mass volume ratio of the first ring-opening reagent to the first solvent is 1 g: 1.5 mL~2 mL.

[0018] In some embodiments, the molar ratio of the epoxy groups in the epoxidized vegetable oil to the second ring-opening reagent is 1:0.1-0.2; and the reaction temperature of the second ring-opening reaction is 60-100°C.

[0019] In some embodiments, preferably, the reaction temperature of the second ring-opening reaction is 70-100°C, more preferably 80°C.

[0020] In some embodiments, the second ring-opening reaction is carried out in a second solvent, and the second solvent is any one or a combination of water, methanol, ethanol, isopropanol, 1-propanol, 1-butanol, 2-butanol, propionic acid and acetonitrile; the mass volume ratio of the second ring-opening reagent to the second solvent is 1 g: 1 mL~4 mL.

[0021] In some embodiments, preferably, the second ring-opening reaction is carried out in a second solvent, and the second solvent is water; the mass volume ratio of the second ring-opening reagent to the second solvent is 1 g: 1 mL~3 mL.

[0022] In some embodiments, a microchannel reaction device is used to prepare bio-based polyols, comprising the following steps:

[0023] (1) mixing epoxidized vegetable oil with an acidic catalyst to obtain a first mixed solution; dissolving a first ring-opening reagent in a first solvent to obtain a second mixed solution; and simultaneously pumping the first mixed solution and the second mixed solution into a first microreactor of a microchannel reaction device to perform a first ring-opening reaction to obtain a first reaction solution;

[0024] (2) dissolving a second ring-opening reagent in a second solvent to obtain a third mixed solution; and simultaneously pumping the third mixed solution and the first reaction solution obtained in step (1) into a second microreactor of a microchannel reaction device to perform a second ring-opening reaction to obtain a reaction solution containing bio-based polyols.

[0025] In some embodiments, the epoxidized vegetable oil is any one or a combination of epoxidized olive oil, epoxidized peanut oil, epoxidized rapeseed oil, epoxidized cottonseed oil, epoxidized soybean oil, epoxidized coconut oil, epoxidized palm oil, epoxidized sesame oil, epoxidized corn oil and epoxidized sunflower oil; the acidic catalyst is any one or a combination of fluoroboric acid, phosphoric acid, phosphotungstic acid and lipase CALB.

[0026] In some embodiments, the mass ratio of the epoxidized vegetable oil to the acidic catalyst is 1:0.02%~0.10%; the molar ratio of the epoxy group in the epoxidized vegetable oil to the first ring-opening reagent is 1:0.6~0.8; and the reaction temperature of the first ring-opening reaction is 40~80°C.

[0027] In some embodiments, the first ring-opening reaction is carried out in a first solvent, and the first solvent is any one or a combination of water, ethanol, propylene glycol, methanol, pyridine and 1-propanol; the mass volume ratio of the first ring-opening reagent to the first solvent is 1 g: 0.5 mL~2 mL.

[0028] In some embodiments, the molar ratio of the epoxy groups in the epoxidized vegetable oil to the second ring-opening reagent is 1:0.1-0.2; and the reaction temperature of the second ring-opening reaction is 60-100°C.

[0029] In some embodiments, the second ring-opening reaction is carried out in a second solvent, and the second solvent is any one or a combination of water, methanol, ethanol, isopropanol, 1-propanol, 1-butanol, 2-butanol, propionic acid and acetonitrile; the mass volume ratio of the second ring-opening reagent to the second solvent is 1 g: 1 mL~4 mL.

[0030] In some embodiments, in step (1), the first ring-opening reaction has a reaction residence time of 5 min to 4 h; and the volume of the first microreactor is 5 mL to 2 L.

[0031] In some embodiments, preferably, in step (1), the first ring-opening reaction has a reaction residence time of 5 min to 2 h, more preferably 5 min to 30 min, more preferably 5 min to 15 min, and most preferably 10 min; the volume of the first microreactor is 5 mL to 1 L, more preferably 5 mL to 400 mL, more preferably 5 mL to 20 mL, and most preferably 10 mL.

[0032] In some embodiments, in step (2), the second ring-opening reaction has a reaction residence time of 5 min to 4 h; and the volume of the second microreactor is 5 mL to 2 L.

[0033] In some embodiments, preferably, in step (2), the second ring-opening reaction has a reaction residence time of 5 min to 2 h, more preferably 5 min to 1 h, more preferably 5 min to 40 min, and most preferably 10 min to 15 min; the volume of the second microreactor is 5 mL to 1 L, more preferably 5 mL to 400 mL, more preferably 5 mL to 30 mL, and most preferably 10 mL to 15 mL.

[0034] In some embodiments, the microchannel reaction device includes a connecting pipeline, a first feed pump, a second feed pump, a third feed pump, a first micromixer, a second micromixer, a first microreactor, a second microreactor and a receiver; the first feed pump and the second feed pump are connected to the first micromixer in parallel through a pipeline; the first micromixer is connected to the first microreactor; the first microreactor and the third feed pump are connected to the second micromixer in parallel through a pipeline; the second micromixer is connected in series with the second microreactor and the receiver through pipelines.

[0035] Wherein, the inner diameter of the connecting pipe is 300 μm~10 mm, preferably 300 μm.

[0036] Wherein, the model of the feed pump is L0107-1A.

[0037] Wherein, the micro mixer is a Y-type mixer or a T-type mixer.

[0038] The microreactor is of Vapotech model and uses a coaxial heat exchanger with a microstructure.

[0039] Wherein, the microreactor is heated by an oil bath.

[0040] Wherein, the inner diameter of the internal pipe of the microreactor is 300 μm~10 mm, preferably 300 μm.

[0041] The reaction solution containing the bio-based polyol obtained above is washed with a sodium bicarbonate solution and water in sequence, and the organic phase is dried and concentrated to obtain the bio-based polyol.

[0042] The bio-based polyols prepared by the above-mentioned preparation method are also within the protection scope of the present invention.

[0043] The use of the above-mentioned bio-based polyols in the preparation of bio-based rigid polyurethane foams is also within the protection scope of the present invention.

[0044] Specifically, the application of the bio-based polyol in the preparation of bio-based polyurethane rigid foam and the method for preparing bio-based polyurethane rigid foam using the bio-based polyol can refer to the prior art, and can also be prepared according to the following method:

[0045] Material A: 100 parts of bio-based polyol, 3 parts of foaming agent pentane, 2 parts of cashew nut shell oil diluent, 2 parts of silicone foam stabilizer, 0.4 parts of ethanolamine and organotin, 15 parts of flame retardant Pyrol99; Material B is composite isocyanate. Add material A and material B into the mixing chamber of the sprayer, stir at 50~80℃, 200~300 rpm, spray and foam after mixing, and solidify within 2 minutes after spraying to obtain spray-type polyurethane rigid foam.

[0046] Beneficial effects:

[0047] (1) The present invention uses a novel biomass-derived ring-opening reagent to complete the ring-opening reaction of some epoxy groups through process control, and introduces a rigid structure into the prepared vegetable oil polyol, thereby increasing the mechanical properties of the polyurethane material.

[0048] (2) The present invention uses two specific types of ring-opening reagents to react in series to leave a small amount of epoxy value remaining. The prepared vegetable oil polyol has a novel structure and a moderate and evenly distributed hydroxyl value. It can replace traditional petrochemical polyols. The performance of polyurethane rigid foam materials prepared by the vegetable oil polyol prepared by the present invention is significantly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments, and the above and / or other advantages of the present invention will become more clear.

[0050] Figure 1 Schematic diagram of the microchannel reaction device used in the embodiment of the present invention. DETAILED DESCRIPTION

[0051] The present invention can be better understood according to the following examples. However, it is easy for those skilled in the art to understand that the contents described in the examples are only used to illustrate the present invention, and should not and will not limit the present invention described in detail in the claims.

[0052] The experimental methods described in the following examples are conventional methods unless otherwise specified; the reagents and materials described are commercially available unless otherwise specified.

[0053] Unless otherwise specified, the embodiments of the present invention and the accompanying Figure 1 The vegetable oil polyols in the invention are all the above-mentioned bio-based polyols.

[0054] The relevant determination methods of the prepared vegetable oil polyol and polyurethane material of the present invention are as follows:

[0055] (1) Measure the hydroxyl value according to GB / T 12008.3-2009;

[0056] (2) Measure viscosity according to GB / T 12008.7-2010;

[0057] (3) Measure the epoxy value according to GB / T 1677-2008;

[0058] (4) Determine the apparent density according to GB / T 6243-2009;

[0059] (5) Compression properties are measured according to GB / T 8813-2020.

[0060] Figure 1 This is a schematic diagram of a microchannel reaction device used in an embodiment of the present invention, wherein the microchannel reaction device comprises a connecting pipeline, a first feed pump (pumping epoxidized vegetable oil and an acidic catalyst), a second feed pump (pumping a first ring-opening reagent and a first solvent, wherein the first ring-opening reagent is erythritol), a third feed pump (pumping a second ring-opening reagent and a second solvent, wherein the second ring-opening reagent is lactose), a first micromixer, a second micromixer, a first microreactor, a second microreactor and a receiver; the first feed pump and the second feed pump are connected in parallel to the first micromixer through a pipeline; the first micromixer is connected to the first microreactor; the first microreactor and the third feed pump are connected in parallel to the second micromixer through a pipeline; the second micromixer and the second microreactor and the receiver are connected in series in sequence through pipelines.

[0061] Wherein, the inner diameter of the connecting pipe is 300 μm.

[0062] Wherein, the model of the feed pump is L0107-1A.

[0063] Wherein, the micro mixer is a Y-type mixer.

[0064] The microreactor is of Vapotech model and uses a coaxial heat exchanger with a microstructure.

[0065] Wherein, the microreactor is heated by an oil bath.

[0066] Wherein, the inner diameter of the internal pipe of the microreactor is 300 μm.

[0067] Example 1: Preparation of vegetable oil polyols

[0068] 100 g of epoxidized soybean oil (epoxy value 6.7%) and 200 mg of fluoroboric acid aqueous solution (40 wt%, containing 80 mg of fluoroboric acid) were mixed to obtain a first mixed solution; 35.8 g of erythritol was dissolved in 70 mL of water to obtain a second mixed solution; the temperature of the first microreactor was adjusted to 60°C, and the first mixed solution and the second mixed solution were simultaneously pumped into the first microreactor of the microchannel reaction device at a rate of 0.5 mL / min and 0.5 mL / min, respectively, to carry out a first ring-opening reaction with a reaction residence time of 10 min to obtain a first reaction solution, wherein the volume of the first microreactor was 10 mL.

[0069] 21.5 g lactose was dissolved in 40 mL water to obtain a third mixed solution. The temperature of the second microreactor was adjusted to 80°C, and the third mixed solution was pumped into the second microreactor of the microchannel reaction device at a rate of 0.25 mL / min simultaneously with the first reaction solution for a second ring-opening reaction. The reaction residence time was 12 min to obtain a second reaction solution, wherein the volume of the second microreactor was 15 mL. After the reaction, the second reaction solution was washed with sodium bicarbonate solution (30 mL, 10 wt.%) and water (30 mL×2) in sequence, and the organic phase was dried and concentrated to obtain soybean oil polyol with a hydroxyl value of 253 mg KOH / g, an epoxy value of 0.2, and a viscosity of 2105 mPa•s.

[0070] Example 2: Preparation of vegetable oil polyols

[0071] 100 g of epoxidized soybean oil (epoxy value 6.7%) and 200 mg of fluoroboric acid aqueous solution (40 wt%, containing 80 mg of fluoroboric acid) were mixed to obtain a first mixed solution; 38.4 g of erythritol was dissolved in 76 mL of water to obtain a second mixed solution; the temperature of the first microreactor was adjusted to 60°C, and the first mixed solution and the second mixed solution were simultaneously pumped into the first microreactor of the microchannel reaction device at a rate of 0.51 mL / min and 0.49 mL / min, respectively, to carry out a first ring-opening reaction with a reaction residence time of 10 min to obtain a first reaction solution, wherein the volume of the first microreactor was 10 mL.

[0072] 28.7 g lactose was dissolved in 56 mL water to obtain a third mixed solution. The temperature of the second microreactor was adjusted to 80°C, and the third mixed solution was pumped into the second microreactor of the microchannel reaction device at a rate of 0.36 mL / min simultaneously with the first reaction solution for a second ring-opening reaction. The reaction residence time was 11 min to obtain a second reaction solution, wherein the volume of the second microreactor was 15 mL. After the reaction, the second reaction solution was washed with sodium bicarbonate solution (30 mL, 10 wt.%) and water (30 mL×2) in sequence, and the organic phase was dried and concentrated to obtain soybean oil polyol with a hydroxyl value of 246 mg KOH / g, an epoxy value of 0.1, and a viscosity of 2009 mPa•s.

[0073] Example 3: Preparation of vegetable oil polyols

[0074] 100 g of epoxidized soybean oil (epoxy value 6.7%) and 200 mg of fluoroboric acid aqueous solution (40 wt%, containing 80 mg of fluoroboric acid) were mixed to obtain a first mixed solution; 40.9 g of erythritol was dissolved in 80 mL of water to obtain a second mixed solution; the temperature of the first microreactor was adjusted to 60°C, and the first mixed solution and the second mixed solution were simultaneously pumped into the first microreactor of the microchannel reaction device at a rate of 0.5 mL / min and 0.5 mL / min, respectively, to carry out a first ring-opening reaction with a reaction residence time of 10 min to obtain a first reaction solution, wherein the volume of the first microreactor is 10 mL.

[0075] 14.3 g lactose was dissolved in 28 mL water to obtain a third mixed solution. The temperature of the second microreactor was adjusted to 80°C, and the third mixed solution was pumped into the second microreactor of the microchannel reaction device at a rate of 0.18 mL / min simultaneously with the first reaction solution for a second ring-opening reaction. The reaction residence time was 12.7 min to obtain a second reaction solution, wherein the volume of the second microreactor was 15 mL. After the reaction, the second reaction solution was washed with sodium bicarbonate solution (30 mL, 10 wt.%) and water (30 mL×2) in sequence, and the organic phase was dried and concentrated to obtain soybean oil polyol with a hydroxyl value of 272 mg KOH / g, an epoxy value of 0.1, and a viscosity of 2416 mPa•s.

[0076] Example 4: Preparation of vegetable oil polyols

[0077] 100 g of epoxidized soybean oil (epoxy value 6.7%) and 200 mg of fluoroboric acid aqueous solution (40 wt%, containing 80 mg of fluoroboric acid) were mixed to obtain a first mixed solution; 33.2 g of erythritol was dissolved in 66 mL of water to obtain a second mixed solution; the temperature of the first microreactor was adjusted to 60°C, and the first mixed solution and the second mixed solution were simultaneously pumped into the first microreactor of the microchannel reaction device at a rate of 0.56 mL / min and 0.44 mL / min, respectively, to carry out a first ring-opening reaction with a reaction residence time of 10 min to obtain a first reaction solution, wherein the volume of the first microreactor was 10 mL.

[0078] 28.7 g lactose was dissolved in 56 mL water to obtain a third mixed liquid. The temperature of the second microreactor was adjusted to 80°C, and the third mixed liquid was pumped into the second microreactor of the microchannel reaction device at a rate of 0.39 mL / min simultaneously with the first reaction liquid for a second ring-opening reaction. The reaction residence time was 10.8 min to obtain a second reaction liquid, wherein the volume of the second microreactor was 15 mL. After the reaction, the second reaction liquid was washed with sodium bicarbonate solution (30 mL, 10 wt.%) and water (30 mL×2) in sequence, and the organic phase was dried and concentrated to obtain soybean oil polyol with a hydroxyl value of 239 mg KOH / g, an epoxy value of 0.2, and a viscosity of 1830 mPa•s.

[0079] Example 5: Preparation of vegetable oil polyols

[0080] 100 g of epoxidized soybean oil (epoxy value 6.7%) and 200 mg of fluoroboric acid aqueous solution (40 wt%, containing 80 mg of fluoroboric acid) were mixed to obtain a first mixed solution; 30.7 g of erythritol was dissolved in 60 mL of water to obtain a second mixed solution; the temperature of the first microreactor was adjusted to 60°C, and the first mixed solution and the second mixed solution were simultaneously pumped into the first microreactor of the microchannel reaction device at a rate of 0.57 mL / min and 0.43 mL / min, respectively, to carry out a first ring-opening reaction with a reaction residence time of 10 min to obtain a first reaction solution, wherein the volume of the first microreactor was 10 mL.

[0081] 21.5 g lactose was dissolved in 40 mL water to obtain a third mixed solution. The temperature of the second microreactor was adjusted to 80°C, and the third mixed solution was pumped into the second microreactor of the microchannel reaction device at a rate of 0.29 mL / min simultaneously with the first reaction solution for a second ring-opening reaction. The reaction residence time was 11.6 min to obtain a second reaction solution, wherein the volume of the second microreactor was 15 mL. After the reaction, the second reaction solution was washed with sodium bicarbonate solution (30 mL, 10 wt.%) and water (30 mL×2) in sequence, and the organic phase was dried and concentrated to obtain soybean oil polyol with a hydroxyl value of 247 mg KOH / g, an epoxy value of 0.2, and a viscosity of 1993 mPa•s.

[0082] Example 6: Preparation of vegetable oil polyols

[0083] 100 g of epoxidized soybean oil (epoxy value 6.7%) and 200 mg of fluoroboric acid aqueous solution (40 wt%, containing 80 mg of fluoroboric acid) were mixed to obtain a first mixed solution; 40.9 g of erythritol was dissolved in 80 mL of water to obtain a second mixed solution; the temperature of the first microreactor was adjusted to 60°C, and the first mixed solution and the second mixed solution were simultaneously pumped into the first microreactor of the microchannel reaction device at a rate of 0.5 mL / min and 0.5 mL / min, respectively, to carry out a first ring-opening reaction with a reaction residence time of 10 min to obtain a first reaction solution, wherein the volume of the first microreactor is 10 mL.

[0084] 21.5 g of lactose was dissolved in 40 mL of water to obtain a third mixed solution. The temperature of the second microreactor was adjusted to 80°C, and the third mixed solution was pumped into the second microreactor of the microchannel reaction device at a rate of 0.25 mL / min simultaneously with the first reaction solution for a second ring-opening reaction. The reaction residence time was 12 min to obtain a second reaction solution, wherein the volume of the second microreactor was 15 mL. After the reaction, the second reaction solution was washed with sodium bicarbonate solution (30 mL, 10 wt.%) and water (30 mL×2) in sequence, and the organic phase was dried and concentrated to obtain soybean oil polyol with a hydroxyl value of 260 mg KOH / g, an epoxy value of 0.1, and a viscosity of 2262 mPa•s.

[0085] Comparative Example 1: Preparation of vegetable oil polyols using conventional reactor

[0086] 100 g of epoxidized soybean oil (epoxy value 6.7%), 200 mg of fluoroboric acid aqueous solution (40 wt%, containing 80 mg of fluoroboric acid), 40.9 g of erythritol and 80 mL of water were reacted at 60°C for 6 h. Subsequently, 14.3 g of lactose and 28 mL of water were added to the reaction system and reacted at 100°C for 4 h. After the reaction, the reaction solution was cooled to room temperature and washed with sodium bicarbonate solution (30 mL, 10 wt.%) and water (30 mL×2) in sequence. The organic phase was dried and concentrated to obtain soybean oil polyol with a hydroxyl value of 184 mgKOH / g, an epoxide value of 0.2 and a viscosity of 2883 mPa•s.

[0087] Comparative Example 2: Preparation of vegetable oil polyols

[0088] 100 g of epoxidized soybean oil (epoxy value 6.7%) and 200 mg of fluoroboric acid aqueous solution (40 wt%, containing 80 mg of fluoroboric acid) were mixed to obtain a first mixed solution; 28.7 g of lactose was dissolved in 60 mL of water to obtain a second mixed solution; the temperature of the first microreactor was adjusted to 80°C, and the first mixed solution and the second mixed solution were simultaneously pumped into the first microreactor of the microchannel reaction device at a rate of 0.57 mL / min and 0.43 mL / min, respectively, for a ring-opening reaction. The reaction residence time was 10 min to obtain a first reaction solution, wherein the volume of the first microreactor was 10 mL; after the reaction, the first reaction solution was washed with sodium bicarbonate solution (30 mL, 10 wt.%) and water (30 mL×2) in sequence, and the organic phase was dried and concentrated to obtain soybean oil polyol with a hydroxyl value of 182 mg KOH / g, an epoxy value of 0.7, and a viscosity of 2546 mPa•s.

[0089] Comparative Example 3: Preparation of vegetable oil polyols

[0090] 100 g of epoxidized soybean oil (epoxy value 6.7%) and 200 mg of fluoroboric acid aqueous solution (40 wt%, containing 80 mg fluoroboric acid) were mixed to obtain a first mixed solution; 35.8 g of erythritol was dissolved in 70 mL of water to obtain a second mixed solution; the temperature of the first microreactor was adjusted to 60°C, and the first mixed solution and the second mixed solution were simultaneously pumped into the first microreactor of the microchannel reaction device at a rate of 0.53 mL / min and 0.47 mL / min, respectively, for a ring-opening reaction. The reaction residence time was 10 min to obtain a first reaction solution, wherein the volume of the first microreactor was 10 mL; after the reaction, the first reaction solution was washed with sodium bicarbonate solution (30 mL, 10 wt.%) and water (30 mL×2) in sequence, and the organic phase was dried and concentrated to obtain soybean oil polyol with a hydroxyl value of 270 mg KOH / g and a viscosity of 2682 mPa•s.

[0091] Example 7: Preparation of Bio-based Rigid Polyurethane Foam

[0092] The plant oil polyols prepared in Examples 1 to 6 and Comparative Examples 1 to 3 were used to prepare bio-based polyurethane rigid foams, respectively. The bio-based polyurethane rigid foams were prepared according to the following method:

[0093] Material A: 100 parts of vegetable oil polyol, 3 parts of foaming agent pentane, 2 parts of cashew nut shell oil diluent, 2 parts of organosilicon foam stabilizer, 0.4 parts of ethanolamine and organotin, 15 parts of flame retardant Pyrol99; Material B is composite isocyanate. Add material A and material B into the mixing chamber of the sprayer, stir at 50~80℃, 200~300 rpm, spray and foam after mixing, and solidify within 2 minutes after spraying to obtain spray-type polyurethane rigid foam.

[0094] The performance indicators of the bio-based polyurethane rigid foams prepared using the vegetable oil polyols prepared in Examples 1 to 6 and Comparative Examples 1 to 3 as raw materials are shown in Table 1.

[0095] Table 1 Performance indicators of bio-based polyurethane rigid foams prepared in Examples 1 to 6 and Comparative Examples 1 to 3

[0096]

[0097] The present invention provides a bio-based polyol and its preparation method and application ideas and methods. There are many methods and ways to implement the technical solution. The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the protection scope of the present invention. All components not specified in this embodiment can be implemented by existing technologies.

Claims

1. A method for preparing a bio-based polyol, characterized in that: The epoxidized vegetable oil is subjected to a first ring-opening reaction with an acidic catalyst and a first ring-opening reagent to obtain a first reaction liquid; the first reaction liquid is then subjected to a second ring-opening reaction with a second ring-opening reagent to obtain a reaction liquid containing a bio-based polyol; Wherein, the first ring-opening reagent is erythritol; the second ring-opening reagent is lactose; The first ring-opening reaction and the second ring-opening reaction are carried out in a microchannel reaction device; The molar ratio of the epoxy group in the epoxidized vegetable oil to the first ring-opening reagent is 1:0.6-0.8; The molar ratio of the epoxy groups in the epoxidized vegetable oil to the second ring-opening reagent is 1:0.1-0.

2.

2. The preparation method according to claim 1, characterized in that: The epoxidized vegetable oil is any one of epoxidized olive oil, epoxidized peanut oil, epoxidized rapeseed oil, epoxidized cottonseed oil, epoxidized soybean oil, epoxidized coconut oil, epoxidized palm oil, epoxidized sesame oil, epoxidized corn oil and epoxidized sunflower oil, or a combination thereof; the acidic catalyst is any one of fluoroboric acid, phosphoric acid, phosphotungstic acid and lipase CALB, or a combination thereof.

3. The preparation method according to claim 1, characterized in that: The mass ratio of the epoxidized vegetable oil to the acidic catalyst is 1:0.02%-0.10%; the reaction temperature of the first ring-opening reaction is 40-80°C; The first ring-opening reaction is carried out in a first solvent, and the first solvent is any one or a combination of water, ethanol, propylene glycol, methanol, pyridine and 1-propanol; the mass volume ratio of the first ring-opening reagent to the first solvent is 1g:0.5mL~2mL.

4. The preparation method according to claim 1, characterized in that: The reaction temperature of the second ring-opening reaction is 60-100°C; The second ring-opening reaction is carried out in a second solvent, and the second solvent is any one or a combination of water, methanol, ethanol, isopropanol, 1-propanol, 1-butanol, 2-butanol, propionic acid and acetonitrile; the mass volume ratio of the second ring-opening reagent to the second solvent is 1 g: 1 mL~4 mL.

5. The preparation method according to claim 1, characterized in that: The steps include: (1) mixing epoxidized vegetable oil with an acidic catalyst to obtain a first mixed solution; dissolving a first ring-opening reagent in a first solvent to obtain a second mixed solution; and simultaneously pumping the first mixed solution and the second mixed solution into a first microreactor of a microchannel reaction device to perform a first ring-opening reaction to obtain a first reaction solution; (2) dissolving a second ring-opening reagent in a second solvent to obtain a third mixed solution; and simultaneously pumping the third mixed solution and the first reaction solution obtained in step (1) into a second microreactor of a microchannel reaction device to perform a second ring-opening reaction to obtain a reaction solution containing bio-based polyols.

6. The preparation method according to claim 5, characterized in that: In step (1), the first ring-opening reaction has a reaction residence time of 5 min to 4 h; and the volume of the first microreactor is 5 mL to 2 L.

7. The preparation method according to claim 5, characterized in that: In step (2), the second ring-opening reaction has a reaction residence time of 5 min to 4 h; and the volume of the second microreactor is 5 mL to 2 L.

8. The preparation method according to claim 5, characterized in that: The microchannel reaction device comprises a connecting pipeline, a first feed pump, a second feed pump, a third feed pump, a first micromixer, a second micromixer, a first microreactor, a second microreactor and a receiver; the first feed pump and the second feed pump are connected to the first micromixer in parallel through a pipeline; the first micromixer is connected to the first microreactor; the first microreactor and the third feed pump are connected to the second micromixer in parallel through a pipeline; the second micromixer, the second microreactor and the receiver are connected in series in sequence through pipelines.

9. The bio-based polyol prepared by the preparation method according to any one of claims 1 to 8.

10. Use of the bio-based polyol according to claim 9 in the preparation of bio-based rigid polyurethane foam.

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