Polymer polyol with good flowing property in presence of dichloromethane

Abstract

The invention provides a polymer polyol with good flowing property in the presence of dichloromethane. The particle size distribution of the polymer polyol is composed of at least two peak values, one peak value is 200-700nm, the other peak value is 2000-7000nm, preferably, the volume ratio of particles with the particle size peak value of 200-700nm of the polymer polyol is greater than or equal to 75%, the volume ratio of particles with the particle size peak value of 2000-7000nm of the polymer polyol is less than or equal to 15%, and the volume ratio of particles with the particle size peak value of less than 200nm is less than or equal to 1%. The polymer polyol has good fluidity in the presence of dichloromethane, and the polymer polyol can obtain polyurethane foam with excellent batch stability.

Description

Technical Field

[0001] The present invention belongs to the technical field of polymer polyols, and particularly relates to a polymer polyol having good flowability in the presence of dichloromethane. Background Art

[0002] Polymer polyol (abbreviation: POP) is an important variety of polyols for polyurethane foam plastics. The initial development of polymer polyol was based on the considerations of cost reduction and improvement of the load-bearing performance of foam plastics. Its preparation process generally uses styrene and acrylonitrile for free radical dispersion polymerization in basic polyether polyols, and there have been many patent literatures reported, such as those introduced in Chinese patents CN00805650.1 and CN201580023607.4.

[0003] Polymer polyols are usually used to prepare polyurethane foams, especially flexible polyurethane foams. In this process, physical or chemical blowing agents are generally used. Among them, physical blowing agents such as dichloromethane as a blowing agent can make the polyurethane foam have a lower density and is currently the most widely used in the industry, as described in CN113912808A. However, with the popularization of automation, large-scale and mechanized foaming requires mixing POP, dichloromethane and various additives into a combined polyether for use. In this process, if high solid content POP is used, such as when the solid content exceeds 46%, when POP is mixed with dichloromethane, it will cause swelling, deformation and adhesion of styrene acrylonitrile polymer particles, resulting in uneven mixing, blocking the conveying pipeline, and even agglomeration and unusability. This phenomenon is generally considered in the industry to be the influence of the particle size of polymer polyols. Previous patents CN115106041A and CN114644733A also introduced the correlation between particle size and the flowability of polymer polyols, but they all focused on the work of filter residue and storage stability, and did not reveal the influence of particle size on the filtration performance in the presence of dichloromethane. There is no report in existing literature patents and the like on how to solve the problem of high viscosity or difficult filtration after mixing with dichloromethane during the preparation of polyurethane foam with high solid content polymer polyols.

[0004] In summary, there is an urgent need to develop a preparation process or method for polymer polyols having good flowability in the presence of dichloromethane. Summary of the Invention

[0005] In order to solve the problem of high viscosity after mixing with dichloromethane during the preparation of polyurethane foam with high solid content polymer polyols, one of the purposes of the present invention is to provide a polymer polyol having good flowability in the presence of dichloromethane, and this polymer polyol can obtain excellent polyurethane foam with good batch stability.

[0006] To achieve the above-mentioned invention purpose, the present invention adopts the following technical scheme:

[0007] A polymer polyol having good flowability in the presence of methylene chloride, wherein the particle size distribution in the polymer polyol consists of not less than two peaks, one peak being 200 nm to 700 nm and one peak being 2000 nm to 7000 nm.

[0008] In the present invention, by regulating the particle size and proportion of too small particles in the polymer polyol, the swelling performance of methylene chloride can be slowed down. For example, small particles below 200 nm, due to their larger specific surface area, will swell and adhere after being mixed with methylene chloride, resulting in poor filtration performance.

[0009] In one embodiment of the present invention, the volume ratio of the particulate matter between the peak particle sizes of 200 nm to 700 nm of the polymer polyol is greater than or equal to 75%, the volume ratio of the particulate matter between the peak particle sizes of 2000 nm to 7000 nm is less than or equal to 15%, and the volume ratio of the particulate matter below 200 nm is less than or equal to 1%; preferably, the volume ratio of the particulate matter between 220 nm and 680 nm is greater than or equal to 83%, the volume ratio of the particulate matter between 2500 nm and 6000 nm is less than or equal to 12%, and the particulate matter below 200 nm is not detected or the volume ratio is less than or equal to 0.5%.

[0010] In the present invention, the content of unsaturated double bonds in the continuous phase of the polymer polyol is affected not only by the inherent unsaturation of the basic polyether polyol, but also by various factors during the synthesis process and changes, such as the influence of unsaturated monomers such as styrene, acrylonitrile, macromonomers, chain transfer agents, etc.; the influence of free radical polymerization temperature on the basic polyether polyol, the generation of oligomeric SAN small molecules, etc. In order to distinguish from the inherent unsaturation of the basic polyether polyol, after the particulate solid phase removal operation for testing the influence of unsaturation of the polymer polyol of the present invention, the content of unsaturated double bonds in the residual liquid phase is 0.002 to 0.01 mmole / g. Therefore, for polymer polyols with small particle sizes, basic polyethers with different synthesis processes and different unsaturations are used for aging and treatment to induce the aggregation of fine particles less than or equal to 200 nm and reduce their content, which can further improve the methylene chloride resistance of POP.

[0011] As is known to those skilled in the art, the particulate solid phase removal operation of the polymer polyol in the present invention is to add insoluble alcohol, and then after centrifuging to remove the lower layer of solids, the upper layer of supernatant is subjected to vacuum removal of insoluble alcohol.

[0012] As an implementable means, the centrifuge speed is 8000 - 20000 revolutions / min, the insoluble alcohol is selected from methanol, ethanol or isopropanol, and the vacuum removal operation is at 80 - 120 °C and 1 - 20 kPa.

[0013] Another object of the present invention is to provide a method for preparing polymer polyol.

[0014] A method for preparing polymer polyol, wherein the polymer polyol is the above-mentioned polymer polyol, and the method comprises the following steps:

[0015] S1: A mixture of an ethylenically unsaturated monomer, polyether polyol 1 and a macromonomer is subjected to free radical polymerization in the presence of a free radical initiator and a transfer agent to obtain a crude product;

[0016] S2: The ethylenically unsaturated monomer and the chain transfer agent in the crude product are removed to obtain a polymer polyol stock solution, which is mixed and aged with polyether polyol 2 to obtain a polymer polyol product.

[0017] S1 is a conventional step for synthesizing POP, and the materials used, their proportions or operating conditions are well known in the art.

[0018] In one embodiment of the present invention, the ethylenically unsaturated monomer in S1 includes one or more of aromatic olefins, unsaturated nitriles, acrylic acid and methacrylic acid esters, preferably includes one or more of styrene, methylstyrene, chlorostyrene, (meth)acrylic acid methyl ester, (meth)acrylic acid ethyl ester, (meth)acrylic acid nonyl ester, acrylonitrile, methacrylonitrile, more preferably one or more of styrene and acrylonitrile, particularly preferably a composition of styrene and acrylonitrile with a mass ratio of 10:90 - 90:10, and most preferably a composition of styrene and acrylonitrile with a mass ratio of 60:40 - 90:10.

[0019] In one embodiment of the present invention, polyether polyol 1 in S1 is a substance commonly used in the art as understood by those skilled in the art, and it can be obtained by reacting a starting compound having multiple active hydrogen atoms with an alkylene oxide (the alkylene oxide is any one or a combination of ethylene oxide, propylene oxide and butylene oxide). Preferably, the number average molecular weight is 2500 - 7000, the hydroxyl functionality is 2 - 4, and the weight content of ethylene oxide chain segment ethylene oxide is 7 - 11 wt%; preferably, polyether polyol 1 is obtained by using glycerol as a starting agent and subjecting ethylene oxide and propylene oxide to ring-opening polymerization under the catalysis of a double metal catalyst;

[0020] In one embodiment of the present invention, the macromonomer in S1 includes, but is not limited to, the reaction product of a hydroxy compound and a polymerizable double bond-containing compound, preferably the reaction product of a polyether polyol and a polymerizable double bond-containing compound. The polymerizable double bond-containing compound is preferably acrylic acid, methacrylic acid or their derivatives, isocyanates containing double bonds, maleic anhydride, fumaric acid or their derivatives, cinnamic acid or its derivatives, 2,4-hexadienoic acid or its derivatives, etc. One or more of hydroxypropyl methacrylate, glycidyl methacrylate, isopropenyl dimethylbenzyl isocyanate and maleic anhydride are preferred. The polyether polyol for preparing the macromonomer preferably has a number average molecular weight of 6,000 to 20,000 and a hydroxyl functionality of 3 to 6 polyoxyalkylene polyether polyols. In the preparation process of the macromonomer, the amount of the reactive unsaturated compound is preferably in the range of 0.8 to 1.2 moles per mole of the polyol.

[0021] As an alternative embodiment, the preparation of the macromonomer using maleic anhydride is described in the published patent CN105949408B, the macromonomer prepared using isopropenyl dimethylbenzyl isocyanate is introduced in the patent CN201480016215.0, and the use of glycidyl methacrylate is introduced in CN200880010975.5.

[0022] In one embodiment of the present invention, the radical initiator in S1 is an organic peroxide and / or an azo compound, preferably including one or more of tert-amyl peroxy-2-ethylhexanoate, lauroyl peroxide, butyl peroxy-2-ethylhexanoate, di-tert-butyl cyclohexyl peroxide ether, di-tert-amyl cyclohexyl peroxide ether, dimethyl azoditetramelate, azobisisobutyronitrile (AIBN) and azodimethylbutyronitrile (AMBN), and more preferably one or more of di-tert-butyl cyclohexyl peroxide ether, di-tert-amyl cyclohexyl peroxide ether, tert-amyl peroxy-2-ethylhexanoate and tert-butyl peroxy-2-ethylhexanoate.

[0023] In one embodiment of the present invention, the transfer agent in S1 is selected from one or more of toluene, isopropanol, 2-butanol, dodecyl mercaptan, and isopropanol is preferred; preferably, the mass ratio of the ethylenically unsaturated monomer, polyether polyol 1, macromonomer, radical initiator, and chain transfer agent is (40 - 60):(1 - 5):(30 - 60):(0.05 - 2):(1 - 10), and the preferred mass ratio is (43 - 50):(2 - 4):(40 - 50):(0.1 - 1):(2 - 6).

[0024] In one embodiment of the present invention, the radical polymerization in S1 is carried out by one of batch method, semi-continuous method, and continuous method.

[0025] In one embodiment of the present invention, the temperature in step S1 is 80 - 130 °C, preferably 90 - 110 °C.

[0026] In one embodiment of the present invention, the polyether polyol 2 in S2 is obtained by reacting a starting compound having multiple active hydrogen atoms with an alkylene oxide, wherein the alkylene oxide is one or more of ethylene oxide, propylene oxide, and butylene oxide. Preferably, the number average molecular weight of the polyether polyol 2 is 500 to 14,000, the hydroxyl functionality is 2 to 6, and the weight content of ethylene oxide is 7 to 11 wt%. Preferably, the polyether polyol 2 is obtained by ring-opening polymerization of glycerol as a starting agent with a basic catalyst. Preferably, the basic catalyst is potassium hydroxide and / or a phosphazene base compound.

[0027] In one embodiment of the present invention, the mass ratio of the polyether polyol 2 in S2 to the polymer stock solution is 1 to 10:100.

[0028] In one embodiment of the present invention, the aging temperature of S2 is 30 to 130 °C, preferably 60 to 100 °C.

[0029] In one embodiment of the present invention, the aging time of S2 is 0.5 to 3 h.

[0030] Another object of the present invention is to provide a use of a polymer polyol.

[0031] A use of a polymer polyol, wherein the polymer polyol is the polymer polyol prepared by the above method or the above polymer polyol, and the polymer polyol is used as a polymer polyol having good flowability in the presence of dichloromethane, preferably for the field of flexible polyurethane foams.

[0032] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0033] The polymer polyol has a low degree of unsaturation, a reasonable particle size distribution of POP, and excellent flowability after being mixed with the blowing agent dichloromethane during the downstream polyurethane foaming process, and there will be no blockage of the filter. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figures 1 to 3 It is a particle size distribution diagram of the polymer polyol of Examples 1 to 3, wherein the abscissa represents the particle size (nm) and the ordinate represents the scattered light intensity;

[0035] Figure 4 It is a particle size distribution diagram of the polymer polyol of Comparative Example 1, wherein the abscissa represents the particle size (nm) and the ordinate represents the scattered light intensity;

[0036] Figure 5 On the left is the diagram of the residue on the filter screen of the dichloromethane filtration performance test of Example 1, and on the right is the diagram of the residue on the filter screen of the dichloromethane filtration performance test of Comparative Example 1. Detailed Embodiments

[0037] The present invention will be described in detail by way of specific embodiments. The scope of the present invention is not limited by the specific embodiments, but is defined by the claims.

[0038] Viscosity: Measured in millipascal - seconds (mPa·s) at 25 °C using an Anton Paar SVM3000 viscometer.

[0039] Particle size: Measured using a Malvern Nano ZS90 particle size analyzer, a polystyrene detection cell, diluted 10,000 times with ethanol, at 25 °C.

[0040] The abbreviations and meanings of the compounds used in the present invention are described as follows:

[0041] Macromonomer A: Macromonomer polyether polyol, a KOH - catalyzed polyether polyol prepared by reacting glycerol with propylene oxide and ethylene oxide, Wanhua Chemical Group Co., Ltd., F3128, number - average molecular weight 6000, EO content 14 wt%, reacted with maleic anhydride and then end - capped with EO, viscosity 4100 cp@25 °C.

[0042] Macromonomer B: Macromonomer polyether polyol, a phosphazene - base - catalyzed polyether polyol prepared by reacting pentaerythritol with propylene oxide and ethylene oxide, Wanhua Chemical Group Co., Ltd., S6028, number - average molecular weight 8000, EO content 10 wt%, mixed with isopropenyldimethylbenzyl isocyanate and catalyzed with stannous octoate at 80 °C for 2 h to prepare, viscosity 2300 cp@25 °C.

[0043] Macromonomer C: Macromonomer polyether polyol, a phosphazene - base - catalyzed polyether polyol prepared by reacting sorbitol with propylene oxide and ethylene oxide, Wanhua Chemical Group Co., Ltd., F6111, number - average molecular weight 12000, EO content 8 wt%, mixed with hydroxypropyl methacrylate and TDI at 60 °C and stirred for 1 h, then stannous octoate was added and the temperature was raised to 80 °C and reacted for another 2 h to prepare, viscosity 8750 cp@25 °C.

[0044] Polyether polyol 1 - A: Basic polyether polyol, a flexible foam polyether polyol with a functionality of 3 prepared using glycerol as the initiator and reacting with propylene oxide and ethylene oxide via a double - metal catalyst, and the catalyst was not removed. Wanhua Chemical Group Co., Ltd., F3156, hydroxyl value 56.2 mgKOH / g, EO content 8.6 wt%, number - average molecular weight 2994.

[0045] Polyether Polyol 1-B: A basic polyether polyol, a flexible foam polyether polyol with a functionality of 2.8 prepared by reacting glycerol and ethylene glycol as initiators with propylene oxide and ethylene oxide using a double metal catalyst, and the catalyst has not been removed. Wanhua Chemical Group Co., Ltd., F3165, hydroxyl value 65.5 mg KOH / g, EO content 9.0 wt%, number average molecular weight 2400.

[0046] Polyether Polyol 2-A: A basic polyether polyol, a flexible foam polyether polyol with a functionality of 3 prepared by reacting glycerol as an initiator with propylene oxide and ethylene oxide using a KOH catalyst, neutralized with phosphoric acid and filtered through magnesium silicate adsorption. Wanhua Chemical Group Co., Ltd., F3160, hydroxyl value 60.10 mg KOH / g, EO content 9.6 wt%, number average molecular weight 2800.

[0047] Polyether Polyol 2-B: A basic polyether polyol, a flexible foam polyether polyol with a functionality of 2.9 prepared by reacting glycerol and ethylene glycol as initiators with propylene oxide and ethylene oxide using a phosphazene base catalyst, neutralized with phosphoric acid and filtered through magnesium silicate adsorption. Wanhua Chemical Group Co., Ltd., F3135A, hydroxyl value 35 mg KOH / g, EO content 10.5 wt%, molecular weight 4650.

[0048] Initiator E: tert-Amyl peroxy 2-ethylhexanoate, Nouryon Chemicals Co., Ltd.;

[0049] Initiator F: Di-tert-amyl cyclohexyl peroxide ether, Nouryon Chemicals Co., Ltd.;

[0050] Initiator G: tert-Butyl peroxy 2-ethylhexanoate, Nouryon Chemicals Co., Ltd.;

[0051] Isopropanol: Aladdin reagent;

[0052] 2-Butanol: Aladdin reagent;

[0053] Unsaturation: Take 5 g of polymer polyol, dilute it with 500 ml of absolute ethanol, ultrasonically disperse for 30 min, then centrifuge at 8000 rpm for 30 min, take the supernatant, remove ethanol under vacuum, and measure the unsaturation. Refer to GBT 12008.6-2010 Plastics - Polyether polyols - Part 6: Determination of unsaturation;

[0054] Dichloromethane filtration performance test: Take 100 g of polymer polyol, add 10 g of dichloromethane at 20 °C, stir and mix for 2 min, then let it stand for 30 minutes, and filter through a 60-mesh metal filter for 20 min, and observe the residue on the filter.

[0055] Preparation steps of polymer polyol:

[0056] In a stirred tank reactor, place the macromonomer and polyether polyol 1 at the bottom of the tank. After purging with nitrogen, mix them thoroughly. Keep the polymerization temperature controlled at 90 - 110 °C. Add a mixture of fully mixed styrene, acrylonitrile, polyether polyol 1, chain transfer agent, and initiator from the top of the tank at a certain flow rate. Control the pressure at 5 bar during the reaction process. After the dropping is completed, raise the temperature to 120 °C. After aging for 2 h, connect to a vacuum system and maintain the vacuum at 10 kPa for 1 h. Introduce 2S steam for bubbling, keep the steam flow rate at 1 m / s, and continue to remove monomers for 2 h. Mix with polyether polyol 2 at a certain temperature for a certain time, and then cool down to obtain the polymer polyol product.

[0057] Examples 1 - 5

[0058] The data is shown in the following table.

[0059] Comparative Example 1

[0060] The difference from Example 1 is that polyether polyol 1 is used during the aging process.

[0061] Comparative Example 2

[0062] The difference from Example 1 is that polyether polyol 2 is used for synthesizing the polymer stock solution.

[0063] Comparative Example 3

[0064] The difference from Example 1 is that polyether polyol 2 is used for synthesizing the polymer stock solution and polyether polyol 1 is used during the aging process.

[0065] The specific parameters and indicators are shown in Tables 1 and 2 below

[0066] Table 1 Polymer polyol synthesis parameters

[0067]

[0068] Table 2 Polymer polyol indicators

[0069]

[0070] Note: In Table 2, "√" indicates good filtration effect, and the number of solid residues on the filter screen ≤ 20; "×" indicates poor filtration effect, and the number of solid residues on the filter screen > 20.

Claims

1. A polymer polyol having good flow properties in the presence of dichloromethane, characterized in that, The particle size distribution in the polymer polyol consists of no less than two peaks, one peak being 200 nm to 700 nm and the other peak being 2000 nm to 7000 nm; Preferably, the volume proportion of the particulate matter between the particle size peaks of 200 nm to 700 nm in the polymer polyol is greater than or equal to 75%, the volume proportion of the particulate matter between the peaks of 2000 nm to 7000 nm is less than or equal to 15%, and the volume proportion of the particulate matter below 200 nm is less than or equal to 1%; preferably, the volume proportion of the particulate matter between 220 nm to 680 nm is greater than or equal to 83%, the volume proportion of the particulate matter between 2500 nm to 6000 nm is less than or equal to 12%, and the volume proportion of the particulate matter below 200 nm is less than or equal to 0.5%.

2. The polymer polyol according to claim 1 or 2, characterized in that, After the polymer polyol undergoes the operation of removing the solid phase of the particulate matter that affects the unsaturation test, the content of unsaturated double bonds in the residual liquid phase is 0.002 to 0.01 mmol / g; Preferably, the operation of removing the solid phase of the particulate matter is to add an insoluble alcohol, and then after centrifuging to remove the lower-layer solid, perform the operation of vacuum-removing the insoluble alcohol on the upper-layer supernatant.

3. A method for preparing a polymer polyol, wherein the polymer polyol is the polymer polyol according to claim 1 or 2, characterized in that, The method comprises the following steps: S1: A mixture of an ethylenically unsaturated monomer, polyether polyol 1, and a macromonomer undergoes free radical polymerization in the presence of a free radical initiator and a transfer agent to obtain a crude product; S2: Remove the ethylenically unsaturated monomer and the chain transfer agent from the crude product to obtain a polymer polyol stock solution, mix and age it with polyether polyol 2 to obtain a polymer polyol product.

4. The method according to claim 3, wherein The polyether polyol 1 in S1 is obtained by reacting a starting compound having multiple active hydrogen atoms with an alkylene oxide, wherein the alkylene oxide is one or more of ethylene oxide, propylene oxide, and butylene oxide; preferably, the number average molecular weight of polyether polyol 1 is 2500 to 7000, the hydroxyl functionality is 2 to 4, and the weight content of the ethylene oxide link ethylene oxide is 7 to 11 wt%; Preferably, polyether polyol 1 is obtained by using glycerol as a starting agent and subjecting it to ring-opening polymerization of ethylene oxide and propylene oxide catalyzed by a double metal catalyst.

5. The method according to claim 3, characterized in that, The polyether polyol 2 in S2 is obtained by reacting a starting compound having multiple active hydrogen atoms with an alkylene oxide, wherein the alkylene oxide is one or more of ethylene oxide and propylene oxide; preferably, the number average molecular weight of polyether polyol 2 is 500 to 14000, the hydroxyl functionality is 2 to 6, and the weight content of ethylene oxide is 7 to 11 wt%; Preferably, polyether polyol 2 is obtained by using glycerol as a starting agent and subjecting it to ring-opening polymerization of ethylene oxide and propylene oxide catalyzed by a base; Preferably, the base catalyst is potassium hydroxide and / or a phosphazene base compound; And / or, the mass ratio of polyether polyol 2 to the polymer stock solution in S2 is 1 to 10:100; And / or, the aging temperature in S2 is 30 to 130 °C, preferably 60 to 100 °C; And / or, the aging time in S2 is 0.5 to 3 h.

6. Use of a polymer polyol, wherein the polymer polyol is the polymer polyol prepared by the method according to claim 1 or 2, or is the polymer polyol according to any one of claims 3-5, characterized in that The polymer polyol is used as a polymer polyol having good flowability in the presence of dichloromethane, and is preferably used in the field of flexible polyurethane foams.

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