A modified polyether polyol and a method for its preparation, and a polyurethane foam

Abstract

The application discloses a modified polyether polyol and a preparation method thereof, and polyurethane foam. The preparation method of the modified polyether polyol comprises the following steps: 1) reacting polyoxyalkylene polyether polyol initiator and cyclic fatty acid anhydride to obtain a polyether half ester; and 2) adding cyclic carbonate and a catalyst into the polyether half ester, and increasing the temperature to react, so as to obtain the modified polyether polyol. The modified polyether polyol has the characteristics of high primary hydroxyl content and small EO proportion in polyether molecules. Compared with a synthesis process, the method does not use ethylene oxide, has no three waste emissions, can be mass-produced, and is more green, environmentally-friendly, safe and reliable.

Description

TECHNICAL FIELD

[0001] The present invention relates to the synthesis of a modified polyether polyol and its application, more specifically, the present invention relates to the synthesis of a modified polyether polyol with high primary hydroxyl content and its application in polyurethane soft foam. BACKGROUND

[0002] Ordinary polyether polyols have a series of problems such as poor product quality and application performance due to low molecular weight, high unsaturation and insufficient activity, which limits the application field of PPG. When the relative molecular mass of PPG is high, the number of hydroxyl groups decreases, and it is necessary to increase the relative content of primary hydroxyl groups to improve the reaction activity of the product. Polyether polyol with high primary hydroxyl content, i.e. high-activity polyether, can shorten the curing time when foaming and molding, and the products made from it have high elasticity, energy absorption and high load bearing capacity.

[0003] In the prior art, high-activity polyether is generally prepared using an alkaline compound catalyst. First, the initiator is reacted with PO to grow to a certain molecular weight, then EO is continuously added for end-capping. Alternatively, the initiator is reacted with PO in the presence of a double metal cyanide catalyst (DMC double metal catalyst) to prepare a polyoxypropylene polyol, then the DMC double metal catalyst is passivated by adding an alkali metal hydroxide, and then EO is used for end-capping, as described in JP 1990294319A.

[0004] In the prior art, the primary hydroxyl content of polyether polyols is generally about 60-85%. If the primary hydroxyl content is to be further increased, the EO / PO ratio needs to be increased, which leads to an increase in the EO segment (as known in the industry, the EO segment in a polyether molecule refers to a polyethylene glycol segment, and the EO content in a polyether polyol molecule refers to the polyethylene glycol segment content, molar ratio or mass ratio) in the polyether polyol, thereby reducing the hydrolysis resistance and hygrothermal aging resistance of the polyether polyol and the polyurethane material prepared therefrom. To solve this problem, CN102549043B discloses a method for preparing a polyether polyol by ring-opening of a cyclic ether or cyclic ester, cyclic anhydride, or cyclic carbonate using a DMC catalyst, but does not mention the preparation of a high-activity polyether polyol; CN111087597B and CN102369232B disclose a process for preparing a high-activity polyether polyol using a Lewis acid such as B(C6F5)3 and derivatives thereof, but the acidic catalyst produces small-molecule naphthenic by-products, the yield is reduced, and the use of the organic borane catalyst is expensive, and no industrialization has been reported to date; US5070125A and US5114619A disclose a process for preparing a polyether with high primary hydroxyl content and low unsaturation, using barium hydroxide or strontium hydroxide as a catalyst; CN106947074B and CN1061997C provide a solution using cesium hydroxide; and CN110922580A discloses a solution using a phosphazene catalyst, but the above processes all have the problems of high cost of the catalyst used, difficulty in industrialization, or generation of toxic and hazardous solid waste that is difficult to dispose of, and cannot achieve a high primary hydroxyl polyether polyol at a low EO content (e.g., 5%).

[0005] US4487853A discloses a solution using a cyclic anhydride, which can achieve a high primary hydroxyl content polyether polyol at a low EO content. However, it is well known that the explosion limit of EO is 3-100%, which has a high safety requirement for production and equipment. SUMMARY

[0006] Therefore, the present application provides a modified polyether polyol and a preparation method therefor, and a polyurethane foam material. The prepared polyether polyol has a low EO content and a high primary hydroxyl content, the primary hydroxyl content is greater than 90%, and the EO content in the polyether polyol is less than 5%, which has good compatibility with isocyanate and a fast reaction speed, and endows the downstream foam product with more excellent resilience and support performance, significantly improves the elasticity and comfort of the downstream foam product, and better meets the development trend of light weight, comfort, low odor, and low VOC in the automotive industry.

[0007] To achieve the above object, the present application employs the following technical solutions:

[0008] A modified polyether polyol, the structural schematic formula of which is:

[0009]

[0010] wherein 4≥n≥2, X is a saturated alkylene group of 3 to 6 carbons, Y is -CH2CH2-, and R is a polyoxyethylene or polyoxypropylene or polyoxyethyleneoxypropylene polyether polyol residue.

[0011] The method for preparing the modified polyether polyol according to the present application comprises the following steps: reacting a polyoxyalkylene polyether polyol with a cyclic anhydride to prepare a polyether half-ester, and further reacting the polyether half-ester with a cyclic carbonate to prepare the modified polyether polyol.

[0012] The primary hydroxyl content according to the present application is the molar ratio of primary hydroxyl groups to all hydroxyl groups in the polyether polyol. The modified polyether polyol according to the present application has a primary hydroxyl content of greater than 90%.

[0013] The EO content according to the present application is the mass fraction of ethylene oxide units relative to the mass of the modified polyether polyol. The modified polyether polyol according to the present application has an ethylene oxide unit mass fraction of not more than 5%.

[0014] As a preferred embodiment, the method according to the present application comprises the following steps:

[0015] (1) reacting a polyoxyalkylene polyether polyol and a cyclic aliphatic anhydride at 80-120°C, and continuing the reaction for 0.5-5.5 hours after the reaction is complete to obtain a polyether half-ester;

[0016] (2) adding a cyclic carbonate and a catalyst to the polyether half-ester, and reacting at 140-165°C for 1.0-6.0 hours to obtain the modified polyether polyol.

[0017] Preferably, the above method is carried out in an inert gas atmosphere, preferably nitrogen.

[0018] Preferably, the polyoxyalkylene polyether polyol in step (1) can be any suitable polymerization product of an alkylene oxide or a reaction product of an alkylene oxide and a polyol. Any suitable alkylene oxide can be used, for example one or more of ethylene oxide, propylene oxide, butylene oxide, propylene oxide.

[0019] Preferably, the polyoxyalkylene polyether polyol is an alkylene oxide addition product of one or more of trimethylolpropane, glycerol, pentaerythritol, propylene glycol, and ethylene glycol.

[0020] Further preferably, the polyoxyalkylene polyether polyol is a trimethylolpropane and / or glycerol initiated polyoxypropylene triol having a molecular weight of 2000 to 10,000, preferably 3000-8000.

[0021] Preferably, step (1) can be carried out without catalyst, or an inorganic base or an organic amine can be used as catalyst, suitable inorganic base can be one or more of potassium hydroxide, lithium hydroxide, sodium hydroxide, and the organic amine can be one or more of trialkyl or triaryl amine or alkyl aryl tertiary amine, such as trimethylamine, triphenylamine, dimethyl phenyl amine.

[0022] Preferably, the cyclic fatty acid anhydride in step (1) is one or more of succinic anhydride, malonic anhydride, glutaric anhydride, adipic anhydride.

[0023] Preferably, the molar ratio of the cyclic fatty acid anhydride to the hydroxyl group of the starter is 0.8-1.2:1, preferably 1-1.1:1.

[0024] Preferably, the cyclic carbonate in step (2) is ethylene carbonate.

[0025] Preferably, step (2) can be carried out without catalyst, or a catalyst can be used. Preferably, it is carried out in the presence of a catalyst, and suitable catalysts are quaternary ammonium salt, phosphonium salt and other catalysts that can catalyze the reaction of carbonate and carboxyl group. Preferably, the quaternary ammonium salt catalyst is tetraethylammonium bromide, tetraethylammonium chloride, tetra-n-butylammonium chloride, tetra-n-butylammonium bromide, triethylbenzylammonium chloride, or any combination thereof. Preferably, the phosphonium salt is triphenylphosphonium, benzyltriphenylphosphonium chloride, hexadecyltriphenylphosphonium bromide, benzylsulfonated triphenylphosphonium, hydroxyethylsulfonated triphenylphosphonium, (1,2-dihydroxy)propylsulfonated triphenylphosphonium, tetra-n-butylphosphonium bromide, tetra-n-butylphosphonium iodide, triethylbenzylphosphonium bromide, or any combination thereof.

[0026] Preferably, the amount of catalyst used in step (2) is 0.1‰-5‰, preferably 0.5-3‰, of the mass of the polyether half-ester.

[0027] Preferably, the amount of cyclic carbonate used is 2%-15%, preferably 3-11%, of the mass of the polyether half-ester.

[0028] The modified polyether polyol of the present application is particularly suitable for use in the preparation of polyurethane foam materials, such as flexible polyurethane foam. Accordingly, the present application also provides a polyurethane foam material obtained by foaming a composition comprising the modified polyether polyol of the present application and a polyisocyanate.

[0029] In the present application, the polyisocyanate used in the production of the polyurethane foam can be any of the known isocyanates allowed to be used in the field of polyurethane production (e.g., isocyanates described in Patent Document US5011908A), and from a practical point of view, one or more of aliphatic polyisocyanates, cycloaliphatic polyisocyanates, and aromatic polyisocyanates are preferred. Examples of the aliphatic polyisocyanates include, but are not limited to, 1,6-hexamethylene diisocyanate and the like; examples of the cycloaliphatic polyisocyanates include, but are not limited to, one or more of 1,6-cyclohexyl diisocyanate, 1-isocyanato-3,5,5-trimethyl-1,3-isocyanatomethylcyclohexane, 2,4- and 2,6-hexahydrotoluene-diisocyanate, 4,4'-, 2,2'- and 2,4'-dicyclohexyl-methane diisocyanate and their corresponding isomer mixtures, and the like; examples of the aromatic polyisocyanates include, but are not limited to, one or more of 2,4- and 2,6-toluene diisocyanate (TDI) and corresponding isomer mixtures, 4,4'-, 2,4'- and 2,2'-diphenylmethane diisocyanate (MDI) and corresponding isomer mixtures, a mixture of 4,4'-, 2,4'- and 2,2'-diphenylmethane diisocyanate and polyphenyl polymethylene polyisocyanate (PMDI), and the like; and one or more of modified polyisocyanates derived from these polyisocyanates containing urethane, carbodiimide, allophanate, urea, biuret or isocyanurate groups, and the like.

[0030] In the present application, the equivalent ratio of the NCO groups in the polyisocyanate to the active hydrogen atoms in the polyol combination (the combination refers to a mixture of other raw material components other than the polyisocyanate raw material) (the equivalent ratio of (NCO groups / active hydrogen atoms) x 100), also referred to as the NCO index, can be appropriately adjusted from the viewpoint of the mechanical properties of the polyurethane, and is preferably 80 to 140, more preferably 85 to 120, and particularly preferably 95 to 115.

[0031] The specific production process of the polyurethane foam can employ the corresponding process known in the art, and a polyurethane catalyst, a crosslinking agent, a blowing agent, a foam stabilizer, and the like are often added to the reaction system.

[0032] The polyurethane catalyst can employ the corresponding catalyst commonly used in the art, and examples include one or more of organometallic compounds such as stannous octoate, stannous oleate, dibutyltin dilaurate, dibutyltin acetate, and dibutyltin diacetate, and the like; and one or more of organic amine catalysts such as di(2,2'-dimethylamino)ethyl ether, trimethylamine, triethylamine, triethylene diamine, and dimethyl ethanol amine, and the like. The amount of the polyurethane catalyst used is usually about 0.1 to 3.0 wt% based on the weight of the polyol combination (the combination refers to a mixture of other raw material components other than the polyisocyanate raw material).

[0033] In the preparation of the polyurethane foam, the crosslinking agent can be the crosslinking agent commonly used in the art, for example, including but not limited to glycerol or / and diethanolamine. If a crosslinking agent is used, the amount of the crosslinking agent can be less than 3% (w / w), preferably 0.2-1.5% (w / w) based on the weight of the polyol combination.

[0034] Examples of suitable blowing agents include, but are not limited to, one or more of water, acetone, carbon dioxide, halogenated hydrocarbons, aliphatic alkanes and cycloalkanes, etc. As is well known in the art, the use of water as a blowing agent produces carbon dioxide by reaction with isocyanate, which can be used as a blowing agent. Aliphatic alkanes and cycloalkanes are developed as alternative blowing agents to CFC compounds. The blowing agent can be used alone or in a mixture thereof. The amount of the blowing agent is, for example, 0.1-20% (w / w) based on the weight of the polyol combination.

[0035] Suitable foam stabilizers are, for example, organopolysiloxane surfactants, and the amount of the foam stabilizer can be 0.4-1% (w / w) based on the weight of the polyol combination.

[0036] According to product requirements, 0.1-50% (w / w) of auxiliary agents, such as flame retardants, fillers, light stabilizers, antioxidants, etc., based on the weight of the polyol combination, are also commonly added, which will not be described one by one.

[0037] The present application also provides an article containing the polyurethane foam material described in the present application.

[0038] The technical solution provided by the present application has the following beneficial effects:

[0039] (1) The modified polyether polyol product prepared by the present application has a primary hydroxyl content of more than 90%, and the ratio of EO in the polyether molecule is less than or equal to 5%;

[0040] (2) Compared with the traditional synthesis process of high molecular weight and high activity polyether polyol, the method of the present application does not use ethylene oxide, has no three wastes emission, can be produced on a large scale, and is more green, environmentally friendly, safe and reliable;

[0041] (3) The ester group in the modified polyether polyol prepared by the present application is located at the end of the polyol molecule, and the polyether molecule does not contain ester groups inside, which has better compatibility with isocyanate, gives the polyurethane foam excellent uniform foaming performance, reduces the internal stress of the polyurethane foam, and has uniform opening, fine cells and excellent hydrolysis resistance. DETAILED DESCRIPTION

[0042] In order to better understand the technical solutions of the present application, the content of the present application will be further described below in combination with examples, but the content of the present application is not limited to the following examples only.

[0043] The following describes the raw materials involved in the examples or comparative examples:

[0044] Polyoxyalkylene polyether polyol A: polyether polyol prepared by reacting glycerol with propylene oxide and ethylene oxide, molecular weight 3000, Wanhua Chemical Group Co., Ltd. F3156.

[0045] Polyoxyalkylene polyether polyol B: DMC-catalyzed, ring-opening reaction product of glycerol with propylene oxide, molecular weight 5000.

[0046] Polyoxyalkylene polyether polyol C: DMC-catalyzed, ring-opening reaction product of glycerol with propylene oxide, molecular weight 8000.

[0047] Polyether polyol D: high primary hydroxyl polyether polyol prepared by reacting glycerol with propylene oxide and then using ethylene oxide to cap, molecular weight 5000, primary hydroxyl content 80-85%, Wanhua Chemical Group Co., Ltd. F3135.

[0048] Polymer polyol E: polymer polyol containing styrene, acrylonitrile polymer, Wanhua Chemical Group Co., Ltd. POP2140.

[0049] A33: polyurethane catalyst, 33% triethylenediamine and 67% dipropylene glycol solution, American Gas Chemicals.

[0050] A1: polyurethane catalyst, 70% bis(dimethylaminoethyl) ether in dipropylene glycol solution, 33% triethylenediamine and 67% dipropylene glycol solution, American Gas Chemicals.

[0051] Cell opener: polyol with number average molecular weight 2000-10000 and average functionality 2-4, Wanhua Chemical Group Co., Ltd. F5342.

[0052] 8001: modified MDI (diphenylmethane diisocyanate), Wanhua Chemical Group Co., Ltd.

[0053] B-8715: foam stabilizer, Gohsmit Chemical Co., Ltd.

[0054] Other raw materials involved in the following examples, such as no special instructions, are purchased from Aldrich.

[0055] The following describes the detection methods involved in the examples or comparative examples:

[0056] Hydroxyl value: GB 12008.3-2009 Plastics - Polyether polyols - Part 3: Determination of hydroxyl number;

[0057] Viscosity: GB 12008.7-2010 Plastics - Polyether polyols - Part 7: Determination of viscosity;

[0058] Primary hydroxyl content: ASTM D4273-23 Standard Test Method for Polyurethane Raw Materials: Determination of Primary Hydroxyl Content of Polyether Polyols;

[0059] EO segment content in polyether: Carbon 13 nuclear magnetic resonance spectroscopy (13C NMR) measurement, Bruker Ascend-400.

[0060] Examples 1-3 and Comparative Examples 1-3

[0061] Step (1) reacting the polyether polyol initiator and the cyclic fatty acid anhydride at 80-120°C, and continuing to react for 0.5-5.5h after the reaction is complete, to obtain a polyether half ester;

[0062] Step (2) adding a cyclic carbonate and a catalyst to the polyether half ester, and reacting at 140-165°C for 1.0-6.0h to obtain a modified polyether polyol.

[0063] The specific preparation process parameters are shown in Table 1, and the product indexes are shown in Table 2.

[0064] Table 1 Preparation process parameters

[0065]

[0066] Table 2 Product indexes

[0067] Viscosity cp Acid value mgKOH / g Primary hydroxyl content / % EO segment / % Example 1 850 0.26 95％ 4.50％ Example 2 1200 0.24 96％ 2.70％ Example 3 4200 0.23 96％ 1.70％ Comparative Example 1 1610 0.24 95％ 2.60％ Comparative Example 2 4500 0.25 95％ 3％ Comparative Example 3 1310 1.07 ＜3％ ＜1％

[0068] To illustrate the beneficial aspects of the present application, the downstream application performance foaming evaluation of the polyether polyol was carried out. Since the molecular weight of the polyether affects the hydroxyl value and the corresponding isocyanate R value, it is necessary to select polyether polyols of the same type (such as molecular weight) for foaming test, and then select Examples 2, Comparative Examples 1, 2, 3 and commercially available polyether polyol D for comparison.

[0069] Preparation of polyurethane foam:

[0070] The raw materials and weight parts shown in Table 3 were prepared to prepare a combination, and the combination and isocyanate raw materials were respectively thermostated for 3 hours. Then 100g of the combination was taken, and 60g of isocyanate 8001 The components were mixed in a blender (rotation number 3000 rpm) for 6 seconds. The mixed mixture was then quickly poured into an aluminum open mold (size: length 300 mm, width 300 mm, thickness 50 mm) preheated to 60°C to foam the mixture. After 7 minutes, the foam was removed, and a polyurethane foam was obtained.

[0071] Table 3 Formulation of the combination

[0072]

[0073] The foaming performance of the prepared polyurethane foam was tested and is shown in Table 4 below:

[0074] Table 4 Foaming performance of polyurethane

[0075]

[0076] From the foaming performance of the polyurethane foams of Example 4 and Comparative Examples 4-7, the foams prepared using the high-activity polyether of the present application are superior to the foams prepared using the high-activity polyether of Comparative Example 1 in terms of foaming height, foaming rate, and collapse height, and are superior to the foams prepared using the commercially available product and the polyether of Comparative Examples 2-3. However, the polyether prepared in Comparative Example 1 has a higher viscosity than the high-activity polyether of the present application.

[0077] Those skilled in the art can understand that, under the teaching of the present specification, some modifications or adjustments can be made to the present application. These modifications or adjustments should also be within the scope defined by the claims of the present application.

Claims

1. A modified polyether polyol having the structural formula: ###0001### 4 > n > 2, X is a saturated alkylene group of 3 to 6 carbons, Y is -CH2CH2-, and R is a polyethylene oxide or polypropylene oxide or polyethylene oxide propylene oxide polyether polyol residue. wherein The primary hydroxyl content is greater than 90% and the mass fraction of ethylene oxide segments in the modified polyether polyol is not greater than 5%.

2. The modified polyether polyol of claim 1, wherein, 3. A method of preparing the modified polyether polyol of claim 1 comprising the steps of: (1) reacting a polyalkylene oxide polyether polyol initiator with a cyclic aliphatic acid anhydride at a temperature of 80 to 120°C, and continuing the reaction for 0.5 to 5.5 hours after the reaction is complete to produce a polyether half-ester; and (2) adding a cyclic carbonate and a catalyst to the polyether half-ester and reacting at a temperature of 140 to 165°C for 1.0 to 6.0 hours to produce the modified polyether polyol. The polyalkylene oxide polyether polyol of step (1) is an alkylene oxide polymer or an alkylene oxide reaction product of a polyol; and the alkylene oxide is one or more of ethylene oxide, propylene oxide, and butylene oxide. The polyalkylene oxide polyether polyol of step (1) is an alkylene oxide addition product of one or more of trimethylolpropane, glycerol, pentaerythritol, propylene glycol, and ethylene glycol. The polyalkylene oxide polyether polyol is a trimethylolpropane and / or glycerol initiated polyoxypropylene triol having a molecular weight of 2000 to 10,000.

4. The method of claim 3, wherein, The polyalkylene oxide polyether polyol is a trimethylolpropane and / or glycerol initiated polyoxypropylene triol having a molecular weight of 3000 to 8000.

5. The method of claim 3, wherein, The cyclic aliphatic acid anhydride of step (1) is one or more of succinic anhydride, malonic anhydride, glutaric anhydride, and adipic anhydride.

6. The method of claim 3, wherein, The molar ratio of the cyclic aliphatic acid anhydride to the hydroxyl groups of the initiator is 0.8 to 1.2:

1.

7. The method of claim 3, wherein, The molar ratio of the cyclic aliphatic acid anhydride to the hydroxyl groups of the initiator is 1 to 1.1:

1.

8. The method of claim 3, wherein, The cyclic carbonate of step (2) is ethylene carbonate.

9. The method of claim 3, wherein, The mass ratio of the cyclic carbonate to the polyether half-ester is 2% to 15%.

10. The method of claim 3, wherein, The mass ratio of the cyclic carbonate to the polyether half-ester is 3% to 11%.

11. The method of claim 3, wherein, 14. A polyurethane foam prepared by foaming a composition of the modified polyether polyol of claim 1 or 2 or the modified polyether polyol prepared by the method of any one of claims 3 to 13 and a polyisocyanate.

12. The method of claim 3, wherein, ​ 13. The method of claim 3, wherein, ​ ​

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