A method for preparing high-solid content polymer polyol and the obtained polyether polyol and system

Abstract

The present invention discloses a method for preparing a high-solid content polymer polyol and the obtained polyether polyol and system. The preparation method comprises: (1) adding a basic polyether polyol A into a reactor; (2) mixing a vinyl monomer A, a stabilizer, a basic polyether polyol A, a chain transfer agent A and an initiator A to obtain a reaction mixture; (3) continuously conveying the reaction mixture to the reactor through different feeding points to prepare the polymer polyol. The present invention optimizes the feeding method of the monomer mixture of the polymer polyol reaction: by adopting a multi-point dispersed reaction feeding method, the dispersion effect of the monomer mixture in the reactor is improved; the stable particles in the reaction liquid are further played to solve the storage stability problem of the polymer polyol; the viscosity of the polymer polyol is reduced; and the self-polymerization is prevented from being generated at the junction of the monomer mixture feed port and the reactor, which causes the reaction equipment to shut down.

Description

Technical Field

[0001] The invention belongs to the field of polymer polyols, and in particular relates to a method for preparing high-solid content polymer polyols. Background Art

[0002] Polymer polyol (POP), also known as grafted polyether polyol, is a modified polyether variety made by grafting polymerization with polyether polyol as the initiator (or called basic polyether), vinyl monomer as the grafting monomer, and azo or organic peroxide as the initiator. It not only maintains the original flexibility of the polyether main chain, but also has certain characteristics of the vinyl polymer side chain, such as rigidity and flame retardancy, thereby improving the physical properties of polyurethane products and expanding the application range of polyurethane products. It has been widely used in automotive interiors, furniture mattresses and other fields.

[0003] In the early production of polymer polyols, the only vinyl monomer used was acrylonitrile, and the solid content of the product was 5-25%. The polymer polyol was yellow in color and had high viscosity. Its products were accompanied by problems such as core burning, which seriously limited its application. In the 1980s, a mixture of styrene and acrylonitrile was gradually used to prepare polymer polyols, which greatly improved the color, viscosity and other indicators of the product, and the solid content was also increased to 20-30%. In the 1990s, with the promotion of industrial applications, polymer polyols with a solid content of about 40% and a viscosity of less than 6000mPa.s (25°C) were developed. In recent years, my country's polyurethane industry has flourished, and with the continuous improvement of the national economy, the requirements for polymer polyols have become increasingly higher.

[0004] Patent US5364906 discloses a method for preparing polymer polyols by an intermittent process: adding a dispersant, part of an initiator, and part of a base polyether to a reactor and heating it; adding styrene, acrylonitrile, an initiator, a chain transfer agent, and another part of the polyether to a mixing kettle and cooling it to a certain temperature; after the temperature of the reactor reaches a suitable temperature, adding the materials in the mixing kettle; after the monomer reaction is completed, after post-treatment, a polymer polyol is obtained. Compared with the continuous process, the intermittent process has the problems of high product viscosity and large differences between batches, and its industrial application has been gradually eliminated.

[0005] Patent CN1312302A discloses a method for preparing a continuous polymer polyether polyol, in which a dispersant is activated in an activation kettle and then continuously transferred to a seed polymerization kettle by overflow; styrene, acrylonitrile and the activated dispersant are reacted with an initiator to form a seed polymer polyether polyol in a basic polyether medium, which is then continuously overflowed into two polymerization kettles connected in series to polymerize the seed polymer polyether polyol and the vinyl monomer in one step, and finally dried by a flash tank, a distillation tower and an evaporator to obtain a polymer polyol with a solid content of 42% and a viscosity ≥4000mpa.s.

[0006] Patent CN104045773A adopts a continuous process for producing polymer polyols: the method of the present invention comprises the steps of: in a first mixing kettle, mixing a high-activity basic polyether polyol (polyether terminated with ethylene oxide), a vinyl monomer, a macromonomer, a free radical initiator and a chain transfer agent at a temperature lower than the reaction temperature to form a raw material flow; sending the raw material flow to a second mixing kettle for further mixing and storage; and dripping the raw material flow into a reactor to react and form a polymer polyol. The invention does not involve the preparation of ordinary active polymer polyols (polyethers not terminated with ethylene oxide); and does not describe the way in which the reaction monomer mixture enters the reactor.

[0007] Patent CN103408704A uses polyether prepared by DMC catalyst as the basic polyether polyol, and uses a continuous process to prepare polymer polyol production. The basic polyether in this patent uses a non-ethylene oxide terminated basic polyether synthesized by DMC catalyst, but the solid content of the synthesized polymer polyol is relatively low at 40%, and it does not explain how the vinyl monomer mixture enters the reactor to participate in the reaction. Summary of the invention

[0008] The present invention is to solve the problem that in the process of preparing high-solid content (solid content ≥45%) polymerization degree polyol, self-polymerization is generated at the junction of the monomer mixture feed port and the reactor, causing the reaction equipment to shut down; and the problem that the high-solid content polymer polyol product has high viscosity and poor storage stability. The present invention optimizes the polymer polyol reaction monomer mixture feeding method to provide a new polymer polyol mixture dispersed multi-point controllable injection method. The high-solid content polymer polyol prepared by the injection method has the characteristics of low viscosity and good stability.

[0009] One of the objects of the present invention is to provide a method for preparing a high solid content polymer polyol, comprising the following steps:

[0010] (1) adding base polyether polyol A into a reaction kettle;

[0011] (2) mixing vinyl monomer A, stabilizer, base polyether polyol A, chain transfer agent A and initiator A to obtain a reaction mixture A;

[0012] (3) The reaction mixture A is continuously transported to a reactor through different feeding points to prepare a polymer polyol.

[0013] In the present invention, the basic polyether polyol is obtained by using polyol as an initiator and epoxy compounds (preferably ethylene oxide and propylene oxide) to undergo a ring-opening reaction in the presence of a catalyst (any catalyst disclosed in the prior art can be used).

[0014] In a preferred embodiment, in step (1), the volume ratio of the added basic polyether polyol A to the reactor is (0.2-0.8):1, preferably (0.3-0.6):1.

[0015] In a preferred embodiment, in the reaction mixture (based on the reaction mixture as 100wt%), the weight content of vinyl monomer A is 30% to 50%, the weight content of stabilizer is 5% to 20%, the weight content of basic polyether polyol A is 35% to 50%, the weight content of chain transfer agent A is 0 to 5%, and the weight content of initiator A is 0.1% to 0.5%.

[0016] In a further preferred embodiment, in the reaction mixture, the weight content of vinyl monomer A is 30% to 45%, the weight content of stabilizer is 13% to 18%, the weight content of basic polyether polyol A is 40% to 50%, the weight content of chain transfer agent A is 0 to 2%, and the weight content of initiator A is 0.1% to 0.3%.

[0017] In a preferred embodiment, the stabilizer is prepared by reacting a reaction mixture B including a vinyl monomer B, a chain transfer agent B, a macromonomer (stabilizer precursor), an initiator B and an optional polyether polyol B.

[0018] In a further preferred embodiment, the macromonomer is a modified polyether polyol containing an unsaturated reactive bond (such as a double bond), preferably a modified polyether polyol containing an unsaturated reactive bond (such as a double bond) at the end of the molecular chain.

[0019] Among them, any polyether polyol containing (preferably at the terminal) an unsaturated reactive bond is within the scope of the macromonomer described in the present invention, and there is no particular limitation on its source and preparation, as long as it is a polyether polyol containing an unsaturated reactive bond.

[0020] Preferably, but not limited to, the macromonomer is obtained by reacting polyether polyol B with an ethylenically unsaturated compound, i.e., a modified polyether polyol having a polymerizable unsaturated reactive bond introduced into polyether polyol B. Preferably, the ethylenically unsaturated compound is selected from at least one of anhydride compounds containing unsaturated reactive bonds, acrylate compounds, and isocyanate compounds containing unsaturated reactive bonds, and more preferably at least one of methyl methacrylate, ethyl methacrylate, maleic anhydride, 3-isopropenyl-α,α-dimethylbenzyl isocyanate, and hydroxyethyl methacrylate.

[0021] When an anhydride compound containing an unsaturated reactive bond is used, an epoxy compound is also required for end-capping.

[0022] When preparing the macromonomer, (1) the molar ratio of polyether polyol B to ethylenically unsaturated isocyanate compound is controlled to be (1-20):1, preferably (2-12):1, wherein the molar amount of polyether polyol B is based on the molar amount of hydroxyl groups therein, and the molar amount of ethylenically unsaturated compound is based on the molar amount of ester groups therein. (2) The reaction is carried out at 40-150° C., preferably 60-130° C. (3) The reaction is carried out in the presence of a catalyst, wherein the catalyst is selected from at least one of triethylamine, triethylenediamine, stannous octoate, dibutyltin dilaurate, tetraisobutyl titanate, lead octoate, and iron octoate.

[0023] In the present invention, the functionality of the polyether polyol B is 3 to 8, the number average molecular weight is 9000 to 15000, preferably 10000 to 13000, and the polyether polyol B is preferably a copolymer of ethylene oxide and propylene oxide, and the ethylene oxide segment accounts for 5% to 20% of the total mass of the basic polyether polyol.

[0024] Preferably, the polyether polyol B is obtained by reacting a starter having a functionality of 3 to 8 with an alkylene oxide in the presence of a catalyst.

[0025] (1) The alkylene oxide is selected from ethylene oxide and propylene oxide, wherein the proportion of ethylene oxide is 5 mol% to 20 mol%. When two alkylene oxides are used, the ethylene oxide can be end-capped or can be randomly copolymerized after being fully mixed with propylene oxide.

[0026] (2) The catalyst is well known in the industry, and is preferably at least one selected from alkaline catalysts (such as potassium hydroxide), phosphazene catalysts, and bimetallic catalysts (such as MMC, DMC catalysts).

[0027] The vinyl monomer B, chain transfer agent B, initiator B and vinyl monomer A, chain transfer agent A, initiator A have the same ranges.

[0028] In a further preferred embodiment, the stabilizer is prepared by a double-kettle continuous process.

[0029] Wherein, the double-kettle continuous method can be adopted as disclosed in the prior art.

[0030] The present invention adopts a two-step continuous process, which is a preparation method generally adopted in the industry: firstly, vinyl monomer B, chain transfer agent B, macromonomer (stabilizer precursor), initiator B and optional polyether polyol B are reacted in a continuous double-kettle series to obtain stabilizer (PFS), and then the stabilizer (PFS) is mixed with basic polyether polyol A, vinyl monomer A, stabilizer (PFS), initiator A and chain transfer agent A to prepare a reaction mixture A.

[0031] In a preferred embodiment, in the reaction mixture B, the weight content of vinyl monomer B is 5% to 20%, the weight content of polyether polyol B is 0 to 7%, the weight content of macromonomer (stabilizer precursor) is 15% to 30%, the weight content of chain transfer agent B is 45 to 70%, and the weight content of initiator B is 0.1% to 0.7%.

[0032] In a further preferred embodiment, in the reaction mixture B, the weight content of vinyl monomer B is 10% to 18%, the weight content of polyether polyol B is 0 to 5%, the weight content of macromonomer (stabilizer precursor) is 20% to 28%, the weight content of chain transfer agent B is 50 to 65%, and the weight content of initiator B is 0.3% to 0.6%.

[0033] In a preferred embodiment, the functionality of the base polyether polyol A is 3 to 8, the number average molecular weight is 2000 to 9000, preferably 2500 to 4000, preferably the base polyether polyol A is a copolymer of ethylene oxide and propylene oxide, and the ethylene oxide segment accounts for 5% to 12% of the total mass of the base polyether polyol; and / or, the functionality of the polyether polyol B is 3 to 8, the number average molecular weight is 9000 to 15000, preferably 10000 to 13000, preferably the polyether polyol B is a copolymer of ethylene oxide and propylene oxide, and the ethylene oxide segment accounts for 5% to 20% of the total mass of the base polyether polyol.

[0034] In a further preferred embodiment, the base polyether polyol A and the polyether polyol B are independently obtained as follows: using a compound containing three or more hydroxyl groups as an initiator and alkylene oxide as a monomer, and performing a polymerization reaction to obtain the base polyether polyol A and the polyether polyol B.

[0035] In a further preferred embodiment, the base polyether polyol A and the polyether polyol B are independently obtained as follows: using a compound containing 3 to 4 or more hydroxyl groups as an initiator and an epoxy compound (preferably ethylene oxide and propylene oxide) as a monomer, and reacting them.

[0036] The initiator may be selected from at least one of glycerol, trimethylolpropane and pentaerythritol, with glycerol being preferred. During the epoxidation reaction, different epoxides react in a block and random copolymerization manner.

[0037] In a preferred embodiment, the vinyl monomer A and the vinyl monomer B are independently selected from a mixture of styrene and acrylonitrile.

[0038] In a further preferred embodiment, in the vinyl monomer A and the vinyl monomer B, the weight ratio of styrene to acrylonitrile is independently (20-70):(70-20), preferably (30-50):(50-30).

[0039] For example, the mass ratio of styrene to acrylonitrile is 1 / 2 to 3 / 1, preferably 1 / 1 to 2.5 / 1.

[0040] In a preferred embodiment, the chain transfer agent A and the chain transfer agent B are independently selected from at least one of toluene, isopropanol, dodecanol, n-butanol, tert-butanol, and n-pentanol;

[0041] In a preferred embodiment, the initiator A and the initiator B are independently selected from hydroperoxides and / or azo compounds, preferably at least one selected from azobisisobutyronitrile, lauroyl peroxide, and tert-amyl peroxypivalate.

[0042] In a preferred embodiment, step (3) is carried out at 100-140° C. and 0.4-0.5 MPa to prepare the polymer polyol.

[0043] In a preferred embodiment, in step (3), the different feed points are selected from at least two (preferably three) of feed point one, feed point two and feed point three, wherein feed point one is located at the bottom of the reactor, feed point two is located at the outlet of the external circulation pump of the reactor, and feed point three is located in the middle of the reactor.

[0044] In the present invention, the inventors have found after a large number of experiments that the best effect is achieved when feeding at the three feeding points mentioned above. If three feeding ports are set at the bottom of the reactor, although the feeding is also separated, it will still lead to too high concentration at the feeding point.

[0045] In a further preferred embodiment, step (3) comprises the following sub-steps:

[0046] (3.1) First open a feeding point to feed;

[0047] (3.2) When the feed amount reaches 3% to 10% of the total amount of the reaction mixture, another feed point is opened and the feed is fed simultaneously with the feed point opened in step (3.1);

[0048] (3.3) When the feed amount reaches 12% to 30% of the total reaction mixture, open the third feed point (feeding at the same time as the first two feed points) or increase the feed flow rate of the two already opened feed points.

[0049] Among them, during the initial feeding, there is only part of the base material in the reactor (for example, a 0.5L reactor only has 0.25L of base material). When the external circulation and stirring are turned on, the reaction liquid cannot be fully mixed with the base material. Therefore, in the early stage of the reaction, different feed ports are gradually opened according to the sum of the total feed amount and the base material amount to make the initial reaction more controllable and reduce the occurrence of excessive local concentration during the initiation of the reaction, which leads to self-aggregation of materials.

[0050] In a preferred embodiment, in step (3.1), the feed rate at the feed point is controlled to be 0 to 8.3 g / min, for example, 1 to 4 g / min.

[0051] In a preferred embodiment, in step (3.2), when two feeding points are fed simultaneously, the total feeding rate of the two is independently controlled to be 0 to 8.3 g / min, for example, 3 to 6 g / min.

[0052] In a further preferred embodiment, in step (3.2), when two feeding points are fed simultaneously, the feeding speed ratio between the two is (0.8-1.2):(0.8-1.2), for example, 1:1.

[0053] In a preferred embodiment, in step (3.3), when two or three feeding points are fed simultaneously, the total feeding rate is controlled to be 0 to 8.3 g / min, for example, 4 to 8.3 g / min.

[0054] In a further preferred embodiment, in step (3.3), when two or three feeding points are fed simultaneously, the feeding speed ratio of any two feeding points is (0.8-1.2):(0.8-1.2), for example, 1:1. The above means that when step (3.3) is fed by two feeding points, the feeding speed ratio of the two is (0.8-1.2):(0.8-1.2), and when step (3.3) is fed by three feeding points, the feeding speed ratio of the three is (0.8-1.2):(0.8-1.2):(0.8-1.2).

[0055] Preferably, from step (3.1) to step (3.3), the feed rate is controlled to increase gradually. If the initial reaction rate is too fast, the conversion rate of the reaction monomers such as styrene and acrylonitrile will be reduced, and there is a tendency for self-polymerization. If the total feed rate remains unchanged and is always low, the residence time of the reaction monomers in the reactor will be prolonged, and the viscosity of the product will increase. Therefore, the reaction rate is generally adopted from slow to fast in the process.

[0056] In the present invention, by optimizing the steps and methods for the monomer mixture to enter the reactor, the dispersion effect of the monomer mixture in the reactor can be improved, the stable particles in the reaction liquid can further play a role, the viscosity of the high solid content (45-50%) polymer polyol is reduced, and its stability is improved. At the same time, the shutdown of the reaction equipment caused by the generation of self-polymers at the connection between the feed pipe and the reactor can be avoided.

[0057] In a preferred embodiment, the preparation method is carried out by a double-kettle continuous process, comprising the following steps:

[0058] Step 1, adding the basic polyether polyol A' into the first reaction kettle, then starting the stirring and external circulation pump of the first reaction kettle and heating up;

[0059] Step 2, preheating the second reaction kettle and the de-singling tank, and setting the vacuum degree of the de-singling tank;

[0060] Step 3, continuously conveying the reaction mixture to the first reaction kettle through the different feeding points;

[0061] Step 4, after the first reactor is full, the reaction liquid in the first reactor flows into the second reactor from the bottom of the second reactor through a nozzle located above the reactor in an overflow manner, and the stirring of the second reactor is started at the same time;

[0062] Step 5, automatically adjusting the pressure of the first reactor by using an automatic pressure regulating valve provided on the second reactor, and continuously discharging the reaction liquid from the second reactor;

[0063] Step 6: The reaction liquid discharged from the second reactor enters the preheated single-drying reactor, and the stirring and vacuum of the single-drying reactor are turned on to carry out single-drying treatment;

[0064] Step 7: Cooling and filtering the material after removing the single-solid content to obtain the finished polymer polyol with high solid content.

[0065] In a preferred embodiment, the reaction mixture is obtained before step 3: the base polyether polyol A is cooled to ≤40°C, and then the vinyl monomer A, stabilizer, and chain transfer agent A are added, stirred and mixed thoroughly, and cooled to ≤25°C; then the initiator A is added, stirred and mixed thoroughly, and set aside.

[0066] In a preferred embodiment, in step 1, the stirring and external circulation pump of the first reaction kettle are turned on and the temperature is raised to 100-140°C, preferably 110-135°C.

[0067] In a preferred embodiment, in step 1, the second reactor is preheated to 100-140°C, preferably 110-135°C, the desulfurization tank is preheated to 140-160°C, and the vacuum setting value of the desulfurization tank is ≤0.0095MPa.

[0068] In a preferred embodiment, in step 5, an automatic pressure regulating valve is provided behind the top outlet pipeline of the second reactor, and the regulating valve forms a loop with the pressure of the first reactor, and the reaction liquid is continuously discharged from the second reactor by automatically adjusting the pressure of the first reactor to 0.4-0.5 MPa.

[0069] In a preferred embodiment, in step 6, the single-cell removal treatment is performed for 4 to 6 hours.

[0070] In a preferred embodiment, in step 7, the material after the removal of single crystals is cooled to ≤80° C. in a cooler, and filtered through 120 mesh to obtain the high-solid content polymer polyol product.

[0071] The second object of the present invention is to provide a high solid content polymer polyol obtained by the preparation method described in the first object of the present invention.

[0072] The third object of the present invention is to provide a system for preparing high-solid content polymer polyols, which is used to carry out the preparation method described in one of the objects of the present invention, wherein the system includes a first reactor, a second reactor and a depolymerization reactor connected in sequence, and an external circulation pump is provided on the first reactor for realizing external circulation of the reactor liquid, and multiple feeding points are provided on the first reactor.

[0073] In a preferred embodiment, the multiple feeding points are selected from at least two of feed point one, feed point two and feed point three, wherein feed point one is arranged at the bottom of the reactor, feed point two is arranged at the outlet of the external circulation pump of the reactor, and feed point three is arranged in the middle of the reactor.

[0074] In a preferred embodiment, a pipe opening is arranged above the first reaction kettle and connected to the bottom of the second reaction kettle.

[0075] When the first reactor is full, the reaction liquid in the first reactor flows through the nozzle located above the reactor in an overflow manner and enters the bottom of the second reactor with stirring.

[0076] In a preferred embodiment, an automatic pressure regulating valve is provided behind the top outlet pipeline of the second reactor, and the automatic pressure regulating valve forms a loop with the pressure of the first reactor, and the reaction liquid is continuously discharged from the second reactor by automatically adjusting the pressure of the first reactor.

[0077] In a preferred embodiment, the system further comprises a cooler and a filter, which are sequentially arranged after the single-removal tower.

[0078] The endpoints and any values ​​of the scope disclosed in the present invention are not limited to the precise scope or value, and these scopes or values ​​should be understood to include values ​​close to these scopes or values. For numerical ranges, the endpoint values ​​of each scope, the endpoint values ​​of each scope and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be regarded as specifically disclosed in this article. Hereinafter, in principle, each technical solution can be combined with each other to obtain a new technical solution, which should also be regarded as specifically disclosed in this article.

[0079] Compared with the prior art, the present invention has the following beneficial effects: the present invention optimizes the feeding method of the monomer mixture of the polymer polyol reaction, and by adopting a dispersed multi-point reaction feeding method, the divergence effect of the monomer mixture in the reactor is improved, so that the stable particles in the reaction liquid can further play a role, and the storage stability problem of the polymer polyol is solved; at the same time, the viscosity of the polymer polyol is reduced, and the self-polymerization at the junction of the monomer mixture feed port and the reactor is prevented, which may cause the reaction equipment to shut down. DETAILED DESCRIPTION

[0080] The present invention is described in detail below in conjunction with specific embodiments. It is necessary to point out that the following embodiments are only used to further illustrate the present invention and cannot be understood as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made to the present invention by those skilled in the art based on the contents of the present invention still fall within the scope of protection of the present invention.

[0081] It should also be noted that the various specific technical features described in the following specific embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0082] In addition, the various embodiments of the present invention may be arbitrarily combined as long as they do not violate the concept of the present invention. The technical solutions thus formed belong to part of the original disclosure of this specification and also fall within the protection scope of the present invention.

[0083] The raw materials used in the examples and comparative examples, unless otherwise specified, are disclosed in the prior art, for example, they can be directly purchased or prepared according to the preparation methods disclosed in the prior art.

[0084] In the embodiments and comparative examples, the products were tested as follows:

[0085] Determination of viscosity: according to method B specified in GB / T12008.7-2010;

[0086] Determination of solid content: carried out in accordance with the method specified in GB / T31062-2014;

[0087] Determination of free acrylonitrile and styrene: according to the method specified in GB / T31062-2014.

[0088] The process of preparing the stabilizer PFS-1 in the present invention is as follows:

[0089] 580g of vinyl monomer (mixture of styrene and acrylonitrile, the mass ratio of the two is 50 / 50), 760g of macromonomer, 2000g of isopropanol, and 16g of initiator are prepared into a stabilizer PFS mixed solution. The initiator is azobisisobutyronitrile.

[0090] The macromonomer is obtained as follows: sorbitol is used as an initiator to react with ethylene oxide and propylene oxide (ethylene oxide content is 15 mol%) to obtain a polyether polyol with a molecular weight of 12000, and 3-isopropenyl-α,α-dimethylbenzyl isocyanate is used to graft the obtained polyether polyol to introduce unsaturated double bonds to obtain the macromonomer; wherein the molar ratio of the polyether polyol to the 3-isopropenyl-α,α-dimethylbenzyl isocyanate is 1:0.9, and the grafting reaction is carried out at 105° C. in the presence of a catalyst, stannous octoate.

[0091] The preparation of the stabilizer PFS adopts a two-pot series reaction similar to that of the polymer polyol, and the stabilizer PFS-1 obtained by the reaction is cooled to <30°C for storage.

[0092] [Example 1]

[0093] Add 1200g of the basic polyether polyol PPG-1 cooled to below 40°C into the mixing tank; add 340g of acrylonitrile, 710g of styrene, 430g of stabilizer PFS-1, and 5g of isopropanol; cool to 25°C while stirring; add 9.6g of initiator azobisisobutyronitrile; mix and stir until the azobisisobutyronitrile is completely dissolved and mixed evenly;

[0094] Add 250mL of basic polyether polyol PPG-1 to the 0.5L first reactor, start stirring the reactor, start the external circulation pump, and heat to 120°C; set the reaction temperature to 120°C, set the reaction pressure of the first reactor to 0.45MPa, accurately measure the delivery amount of the mixed liquid through the metering pump, and the mixed liquid enters the first reactor through the feed point located at the bottom of the first reactor in the dispersed multi-point, and initially participates in the reaction at a flow rate of 4 grams per minute; when the reaction amount of the mixed liquid reaches 200g, turn on the external circulation pump of the first reactor, open the dispersed multi-point feed point located at the outlet of the external circulation pump of the reactor Point feed point two, the mixed liquid at feed point two is mixed with the external circulation material through a static mixer and then enters the reactor at the top of the reactor, and feed points one and two are kept in equal proportion and fed simultaneously, with a total feed amount of 6g per minute; when the cumulative reaction total amount of the reaction liquid reaches 400g, open feed point three, which is located in the middle of the reactor, so that the mixed liquid reacts with the base liquid in the reactor through feed point one, feed point two and feed point three, and keep the instantaneous total flow rate of feed point one, feed point two and feed point three at 8.3g per minute, and the instantaneous flow ratio of feed point one, feed point two and feed point three is 1:1:1. The reaction mixture reacts to 1500g (intermediate reaction point), and a crude sample is taken at 80°C after the reactor is cooled, and the free styrene and acrylonitrile contents in the sample are analyzed; when the cumulative reaction amount reaches 2000g, the crude product at the outlet of the second reactor is sent to a monomer removal tank preheated to 150°C, with a vacuum degree of ≤-0.095MPa and stirring to remove free monomers. The monomer removal operation is performed for 5 hours, and the sample is cooled to 80°C through a heat exchanger. Finally, the filtrate obtained by filtering through a 120-mesh filter is the finished polymer polyol POP-1. According to the analytical test method mentioned in the invention, the free acrylonitrile and styrene content, viscosity and solid content are analyzed. The structure is shown in Table 1.

[0095] [Example 2]

[0096] Add 1205g of the basic polyether polyol PPG-1 cooled to below 40°C into the mixing tank; add 346g of acrylonitrile, 713g of styrene, 425g of stabilizer PFS-1, and 6g of isopropanol; cool to 25°C while stirring; add 9.8g of initiator azobisisobutyronitrile; mix and stir until the azobisisobutyronitrile is completely dissolved and mixed evenly;

[0097] Add 250mL of basic polyether polyol PPG-1 to the 0.5L first reactor, start stirring the reactor, start the external circulation pump, and heat to 120°C; set the reaction temperature to 120°C, set the reaction pressure of the first reactor to 0.45MPa, accurately measure the delivery amount of the mixed liquid through the metering pump, and the mixed liquid enters the first reactor through the feed point located at the bottom of the first reactor in the dispersed multi-point, and initially participates in the reaction at a flow rate of 4 grams per minute; when the reaction amount of the mixed liquid reaches 200g, start the first reactor. Open the external circulation pump, and turn on the dispersed multi-point feeding point 2 located at the outlet of the external circulation pump of the reactor. The mixed liquid at the feeding point 2 is mixed with the external circulation material in the static mixer and then enters the reactor at the top of the reactor. Keep feeding at the feeding point 1 and the feeding point 2 in equal proportions, and the total feeding amount is 6g per minute. When the cumulative total reaction amount of the reaction liquid reaches 400g, increase the feeding flow rate of the feeding point 1 and the feeding point 2 in equal proportion, so that the instantaneous total flow rate of the two is 8.3g per minute, and the instantaneous flow rate ratio of the feeding point 1 to the feeding point 2 is 1:1. The reaction mixture reacts to 1500g (intermediate reaction point), and a crude sample is taken at 80°C after the reactor is cooled, and the free styrene and acrylonitrile contents in the sample are analyzed; when the cumulative reaction amount reaches 2000g, the crude product at the outlet of the second reactor is sent to a monomer removal tank preheated to 150°C, with a vacuum degree of ≤-0.095MPa and stirring to remove free monomers. The monomer removal operation is performed for 5 hours, and the sample is cooled to 80°C through a heat exchanger. Finally, the filtrate obtained by filtering through a 120-mesh filter is the finished polymer polyol POP-2. According to the analytical test method mentioned in the invention, the free acrylonitrile and styrene content, viscosity and solid content are analyzed. The structure is shown in Table 1.

[0098] [Example 3]

[0099] Add 1210g of the basic polyether polyol PPG-1 cooled to below 40°C into the mixing tank; add 336g of acrylonitrile, 717g of styrene, 422g of stabilizer PFS-1, and 5g of isopropanol; cool to 25°C while stirring; add 9.3g of initiator azobisisobutyronitrile; mix and stir until the azobisisobutyronitrile is completely dissolved and mixed evenly;

[0100] Add 250mL of basic polyether polyol PPG-1 to the 0.5L first reactor, start the reactor to stir, start the external circulation pump, and heat to 120°C; set the reaction temperature to 120°C, set the reaction pressure of the first reactor to 0.45MPa, accurately measure the mixed liquid delivery amount through the metering pump, and the mixed liquid enters the first reactor through the feed point two located at the outlet of the external circulation pump of the first reactor in the dispersed multi-point, and initially participates in the reaction at a flow rate of 4 grams per minute; when the reaction amount of the mixed liquid reaches 200g, turn on the feed point three, keep the feed points two and three in equal proportions and feed at the same time, and the total feed amount is 6g per minute; when the cumulative reaction amount of the reaction liquid reaches 400g, increase the instantaneous reaction flow rate of each feed point respectively, keep the instantaneous total flow rate of feed point two and feed point three at 8.3g per minute, and the instantaneous flow rate ratio of feed point two and feed three is 1:1. The reaction mixture reacts to 1500g (intermediate reaction point), and a crude sample is taken at 80°C after the reactor is cooled, and the free styrene and acrylonitrile contents in the sample are analyzed; when the cumulative reaction amount reaches 2000g, the crude product at the outlet of the second reactor is sent to a monomer removal tank preheated to 150°C, with a vacuum degree of ≤-0.095MPa and stirring to remove free monomers. The monomer removal operation is performed for 5 hours, and the sample is cooled to 80°C through a heat exchanger. Finally, the filtrate obtained by filtering through a 120-mesh filter is the finished polymer polyol POP-3. According to the analytical test method mentioned in the invention, the free acrylonitrile and styrene content, viscosity and solid content are analyzed. The structure is shown in Table 1.

[0101] [Example 4]

[0102] Add 1208g of the basic polyether polyol PPG-1 cooled to below 40°C into the mixing tank; add 348g of acrylonitrile, 721g of styrene, 441g of stabilizer PFS-1, and 5g of isopropanol; cool to 25°C while stirring; add 9.8g of initiator azobisisobutyronitrile; mix and stir until the azobisisobutyronitrile is completely dissolved and mixed evenly;

[0103] Add 250mL of basic polyether polyol PPG-1 to the 0.5L first reactor, start the reactor stirring and external circulation pump, and heat to 120°C; set the reaction temperature to 120°C, set the reaction pressure of the first reactor to 0.45MPa, accurately measure the mixed liquid delivery amount through the metering pump, and the mixed liquid enters the first reactor through the feed point one located at the bottom of the first reactor among the dispersed multiple points, and initially participates in the reaction at a flow rate of 4 grams per minute; when the reaction amount of the mixed liquid reaches 200g, open the feed point three located in the middle of the reactor, keep the feed point one and the feed point three in equal proportion and feed simultaneously, and the total feed amount is 6g per minute; the cumulative reaction amount of the reaction liquid reaches 400g, increase the reaction flow rate, so that the instantaneous total flow rate of the feed point one and the feed point three is 8.3g per minute, and the instantaneous flow rate ratio of the feed point one and the feed three is 1:1. The reaction mixture reacts to 1500g (intermediate reaction point), and a crude sample of the reactor is taken at 80°C after cooling, and the free styrene and acrylonitrile contents in the sample are analyzed; when the cumulative reaction amount reaches 2000g, the crude product at the outlet of the second reactor is sent to a monomer removal tank preheated to 150°C, with a vacuum degree of ≤-0.095MPa and stirring to remove free monomers. The monomer removal operation is performed for 5 hours, and the sample is cooled to 80°C through a heat exchanger. Finally, the filtrate obtained by filtering through a 120-mesh filter is the finished polymer polyol POP-4. According to the analytical test method mentioned in the invention, the free acrylonitrile and styrene content, viscosity and solid content are analyzed. The structure is shown in Table 1.

[0104] [Comparative Example 1]

[0105] Add 1202 grams of basic polyether polyol PPG-1 cooled to below 40°C into the mixing tank; add 344 grams of acrylonitrile, 715 grams of styrene, 436 grams of stabilizer PFS-1, and 5 grams of isopropanol; cool to 25°C while stirring; add 9.6 grams of initiator azobisisobutyronitrile; mix and stir until the azobisisobutyronitrile is completely dissolved and mixed evenly;

[0106] Add 250mL of basic polyether polyol to the 0.5L first reactor, start the reactor stirring, start the external circulation pump, and heat to 120°C; set the reaction temperature to 120°C, set the reaction pressure of the first reactor to 0.45MPa, accurately measure the mixed liquid delivery amount through the metering pump, and the mixed liquid enters the reactor through the bottom of the first reactor to participate in the reaction (same as the dispersed feeding point one), and starts to participate in the reaction at a flow rate of 4 grams per minute; when the cumulative total amount of the mixed liquid reaction reaches 200g, adjust the reaction flow rate to 6g per minute; when the total reaction amount reaches 400g, adjust the reaction flow rate to 8.3g per minute. The reaction mixture reacts to 1500g (intermediate reaction point), and a crude sample is taken at 80°C after cooling the reactor, and the free styrene and acrylonitrile contents in the sample are analyzed; when the cumulative reaction amount reaches 2000g, the crude product at the outlet of the second reactor is sent to a monomer removal tank preheated to 150°C, with a vacuum degree of -0.095MPa and stirring to remove free monomers. The monomer removal operation is performed for 5 hours, and the sample is cooled to 80°C through a heat exchanger. Finally, the filtrate obtained by filtering through a 120-mesh filter is the finished polymer polyol C-1. According to the analytical test method mentioned in the invention, the free acrylonitrile and styrene content, viscosity and solid content are analyzed. The structure is shown in Table 1.

[0107] [Comparative Example 2]

[0108] Add 1216 grams of basic polyether polyol PPG-1 cooled to below 40°C into the mixing tank; add 347 grams of acrylonitrile, 710 grams of styrene, 431 grams of stabilizer PFS-1, and 5 grams of isopropanol; cool to 25°C while stirring; add 9.6 grams of initiator azobisisobutyronitrile; mix and stir until the azobisisobutyronitrile is completely dissolved and mixed evenly;

[0109] Add 250mL of basic polyether polyol to the 0.5L first reactor, start the reactor stirring, start the external circulation pump, and heat to 120°C; set the reaction temperature to 120°C, set the reaction pressure of the first reactor to 0.45MPa, accurately measure the mixed liquid delivery amount through the metering pump, and the mixed liquid is mixed with the material at the outlet of the external circulation pump of the first reactor and enters the reactor to participate in the reaction (same as the dispersed feeding point two), and starts to participate in the reaction at a flow rate of 4 grams per minute; when the reaction amount of the mixed liquid reaches 200g, adjust the reaction flow rate to 6g per minute; when the total reaction amount reaches 400g, adjust the reaction flow rate to 8.3g per minute. The reaction mixture reacts to 1500g (intermediate reaction point), and a crude sample is taken from the reactor after cooling to 80°C, and the free styrene and acrylonitrile contents in the sample are analyzed; when the cumulative reaction amount reaches 2000g, the crude product from the outlet of the second reactor is sent to a monomer removal tank preheated to 150°C, -0.0956MPa, and with stirring to remove free monomers. The monomer removal operation is performed for 5 hours, and the sample is cooled to 80°C through a heat exchanger. Finally, the filtrate obtained by filtering through a 120-mesh filter is the finished polymer polyol C-2. According to the analytical test method mentioned in the invention, the free acrylonitrile and styrene content, viscosity and solid content are analyzed. The structure is shown in Table 1.

[0110] Table 1:

[0111]

[0112] The present invention has been described in detail above in conjunction with specific implementations and exemplary examples, but these descriptions cannot be understood as limiting the present invention. Those skilled in the art understand that, without departing from the spirit and scope of the present invention, a variety of equivalent substitutions, modifications or improvements may be made to the technical solution of the present invention and its implementation methods, all of which fall within the scope of the present invention. The scope of protection of the present invention shall be subject to the attached claims.

Claims

1. A method for preparing a high solid content polymer polyol, comprising the following steps: (1) Adding base polyether polyol A into the reactor; (2) mixing vinyl monomer A, stabilizer, basic polyether polyol A, chain transfer agent A and initiator A to obtain a reaction mixture A; in step (2), in the reaction mixture A, the weight content of vinyl monomer A is 30% to 50%, the weight content of stabilizer is 5% to 20%, the weight content of basic polyether polyol A is 35% to 50%, the weight content of chain transfer agent A is 0% to 5%, and the weight content of initiator A is 0.1% to 0.5%; (3) continuously conveying the reaction mixture A to a reactor through different feed points to prepare a polymer polyol; the different feed points are selected from feed point 1 and feed point 2, or the different feed points are selected from feed point 2 and feed point 3, wherein feed point 1 is located at the bottom of the reactor, feed point 2 is located at the outlet of the external circulation pump of the reactor, and feed point 3 is located in the middle of the reactor; Step (3) includes the following sub-steps: (3.1) first open a feed point for feeding; (3.2) when the feed amount reaches 3% to 10% of the total reaction mixture, open another feed point and feed simultaneously with the feed point opened in step (3.1); (3.3) when the feed amount reaches 12% to 30% of the total reaction mixture, open the third feed point or increase the feed flow rate of the two opened feed points; in step (3.2), the feed speed ratio of the two is (0.8 to 1.2): (0.8 to 1.2); in step (3.3), the feed speed ratio of any two feed points is (0.8 to 1.2): (0.8 to 1.2).

2. The preparation method according to claim 1, characterized in that: In step (1), the volume ratio of the added basic polyether polyol A to the reactor is (0.2-0.8):

1.

3. The preparation method according to claim 2, characterized in that In step (1), the volume ratio of the added basic polyether polyol A to the reactor is (0.3-0.6):1; and / or In step (2), in the reaction mixture A, the weight content of vinyl monomer A is 30% to 45%, the weight content of stabilizer is 13% to 18%, the weight content of basic polyether polyol A is 40% to 50%, the weight content of chain transfer agent A is 0 to 2%, and the weight content of initiator A is 0.1% to 0.3%.

4. The preparation method according to claim 1, characterized in that: The stabilizer is prepared by reacting a reaction mixture B including a vinyl monomer B, a chain transfer agent B, a macromonomer, an initiator B and an optional polyether polyol B.

5. The preparation method according to claim 4, characterized in that: The macromonomer is a modified polyether polyol containing unsaturated reactive bonds.

6. The preparation method according to claim 4, characterized in that: The functionality of the base polyether polyol A is 3 to 8, and the number average molecular weight is 2000 to 9000; and / or The functionality of the polyether polyol B is 3 to 8, and the number average molecular weight is 9,000 to 15,000.

7. The preparation method according to claim 6, characterized in that: The number average molecular weight of the base polyether polyol A is 2500-4000; and / or The number average molecular weight of the polyether polyol B is 10,000 to 13,000.

8. The preparation method according to claim 4, characterized in that The vinyl monomer A and the vinyl monomer B are independently selected from a mixture of styrene and acrylonitrile; and / or The chain transfer agent A and the chain transfer agent B are independently selected from at least one of toluene, isopropanol, dodecanol, n-butanol, tert-butanol, and n-pentanol; and / or The initiator A and the initiator B are independently selected from hydroperoxides and / or azo compounds.

9. The preparation method according to claim 8, characterized in that In the vinyl monomer A and the vinyl monomer B, the weight ratio of styrene to acrylonitrile is independently (20-70):(70-20); and / or The initiator A and the initiator B are independently selected from at least one of azobisisobutyronitrile, lauroyl peroxide, and tert-amyl peroxypivalate.

10. The preparation method according to claim 9, characterized in that: In the vinyl monomer A and the vinyl monomer B, the weight ratio of styrene to acrylonitrile is independently (30-50):(50-30).

11. The preparation method according to claim 1, characterized in that In step (3.1), the feed rate at the feed point is controlled to be 0-8.3 g / min; and / or In step (3.2), when two feeding points are fed simultaneously, the total feeding rate of the two feeding points is controlled to be 0-8.3 g / min; and / or In step (3.3), when two or three feeding points are feeding simultaneously, the total feeding rate is controlled to be 0~8.3g / min.

12. The preparation method according to any one of claims 1 to 11, characterized in that: The preparation method adopts a double-kettle continuous method, comprising the following steps: Step 1, adding basic polyether polyol A into the first reaction kettle, then starting the stirring and external circulation pump of the first reaction kettle and heating; Step 2: preheat the second reaction kettle and the de-singling tank, and set the vacuum degree of the de-singling tank; Step 3, continuously conveying the reaction mixture to the first reaction kettle through the different feeding points; Step 4, after the first reactor is full, the reaction liquid in the first reactor flows into the second reactor from the bottom of the second reactor through a nozzle located above the reactor in an overflow manner, and the stirring of the second reactor is started at the same time; Step 5, automatically adjusting the pressure of the first reactor by using an automatic pressure regulating valve provided on the second reactor, and continuously discharging the reaction liquid from the second reactor; Step 6: The reaction liquid discharged from the second reactor enters the preheated single-removal reactor, and the stirring and vacuum of the single-removal reactor are turned on to carry out single-removal treatment; Step 7: Cooling and filtering the material after removing the single-solid content to obtain the finished polymer polyol with high solid content.

13. A high solid content polymer polyol obtained by the preparation method according to any one of claims 1 to 12.

14. A system for carrying out the preparation method according to any one of claims 1 to 12, wherein: The system comprises a first reactor, a second reactor and a de-monomerization reactor which are connected in sequence, an external circulation pump is arranged on the first reactor to realize external circulation of the liquid in the first reactor, and a plurality of feed points are arranged on the first reactor; the plurality of feed points are selected from feed point one and feed point two, or the plurality of feed points are selected from feed point two and feed point three, wherein feed point one is arranged at the bottom of the reactor, feed point two is arranged at the outlet of the external circulation pump of the reactor, and feed point three is arranged in the middle of the reactor.

15. The system according to claim 14, characterized in that A pipe opening is provided above the first reaction kettle and connected to the bottom of the second reaction kettle; and / or An automatic pressure regulating valve is arranged behind the top outlet pipeline of the second reactor. The automatic pressure regulating valve forms a loop with the pressure of the first reactor, and the reaction liquid is continuously discharged from the second reactor by automatically regulating the pressure of the first reactor.

16. The system according to any one of claims 14 to 15, characterized in that: The system further comprises a cooler and a filter, which are sequentially arranged after the single-removal tower.

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