CN116265507A - Process for the preparation of polyetherester polyols - Google Patents

Abstract

The invention relates to a preparation method of polyether ester polyol, which mainly solves the problems of large DMC catalyst dosage, low catalytic activity and high product viscosity in the preparation of polyether ester polyol in the prior art, and the invention sequentially comprises the following steps: (a) Adding low molecular weight polyol, caprolactone and DMC catalyst into a reaction kettle for homogenization, wherein the DMC dosage is 30-150 ppm of the total material; (b) heating, degassing, dehydrating and replacing nitrogen; (c) Adding a small amount of propylene oxide to activate the reaction, wherein the addition amount is 2-15% of the total mass of the propylene oxide, and the temperature is 120-130 ℃; (d) The remaining propylene oxide was added dropwise, the molar ratio of caprolactone to total propylene oxide being 1: 1-10, the reaction temperature is 120-140 ℃, and the internal pressure is 1-4 h after the dripping; (e) The technical scheme for vacuumizing and removing the monomer to obtain the polyether ester polyol solves the problems well and can be used in the industrial production of the polyether ester polyol.

Description

Process for the preparation of polyetherester polyols

Technical Field

The invention belongs to the field of polyether esters, and particularly relates to a preparation method of polyether ester polyol.

Background

In the polyurethane industry, the most commonly used polyols are two broad categories, polyether polyols and polyester polyols; the polyurethane materials prepared from the polyether polyols have advantages and disadvantages in performance, wherein the polyether polyols have very excellent hydrolysis resistance, and the polyurethane foam materials prepared based on the polyether polyols have very good low-temperature flexibility, which is mainly due to ether bonds in the molecular structure of the polyether, and the cohesive energy of the ether bonds is relatively low and the polyether polyols are easy to rotate; on the other hand, polyether polyol has low system viscosity, so that the polyether polyol is easy to be mutually dissolved with isocyanate and various assistants, and has good processing performance, but the mechanical performance of polyether-based polyurethane materials is not particularly ideal. The polyurethane material prepared by taking polyester polyol as the base has good mechanical properties, oil resistance and the like, but has poor hydrolysis resistance, poor low-temperature flexibility and harder hand feeling of products compared with the polyurethane material prepared by polyether.

The polyether ester polyol prepared by combining the polyester polyol with the polyether polyol has the characteristics of hydrolysis resistance, low-temperature flexibility, good mechanical property, heat resistance, oil resistance and the like of the polyether polyol, and is required in the market. At present, three modes are mainly adopted to prepare polyether ester polyol, wherein the first method is to blend polyester polyol and polyether polyol physically, but the high viscosity of polyester component often brings inconvenience to operation when the polyester polyol and the polyether polyol are blended simply, and the problem of poor compatibility of polyester and polyether can not be solved, so that the mechanical properties and the like of polyurethane can not reach the expected effect, and the practical operability is poor; the second method is that polyether polyol and carboxylic acid are esterified, and the method of taking part in carboxylic acid esterification of polyether has the problem of low activity of polyether hydroxyl end esterification, and the high temperature condition of esterification reaction is easy to cause side reactions such as decarboxylation, oxidation and the like, so that chain termination is caused, a certain amount of by-products such as short-chain polyester and the like are contained in the system, and the subsequent reaction for preparing polyurethane is influenced. Therefore, if the molecular chain of the polyol contains ether bond and ester group, the polymer obtained by the reaction has the properties of polyether polyol and polyester polyol at the same time, so that the comprehensive performance of the polyurethane foam material is further improved, and the application range of the material is expanded.

The polycaprolactone type polyurethane has the high mechanical properties of the traditional polyester type polyurethane material, excellent wear resistance, oil resistance, thermal stability and other properties, and also has excellent low-temperature flexibility, hydrolysis resistance, weather resistance and other properties; however, the price of caprolactone monomers is relatively high, and polycaprolactone polyols are only used for polyurethane materials with special requirements. If polycaprolactone can be modified to reduce the cost, the types of the oligomer polyol can be further expanded, and the development of the polyurethane industry is promoted.

Chinese patent CN101243119B discloses a process for producing polyester ether poly (mono) polyol, comprising adding an initiator and a DMC catalyst to a pressure-resistant reaction vessel, heating to a predetermined reaction temperature, introducing a cyclic ester compound and an alkylene oxide into the reaction vessel simultaneously or sequentially or in combination of both, and copolymerizing the cyclic ester compound and the alkylene oxide under heating and stirring; however, the DMC catalyst added in the catalyst reaches 1189ppm, the dosage is large, a large amount of metal ions remain in the product, which can cause poor performance of downstream products, and the polyester ether prepared by copolymerization of caprolactone and PO has the viscosity of 700-1100 mpa.s/25 ℃, large viscosity and inconvenient later operation.

U.S. patent No. 5032671a discloses a method for preparing a lactone polymer by using a DMC catalyst, wherein a poly (-caprolactone/propylene oxide) copolymer is prepared by using caprolactone and PO as monomers, and a polyester ether product with a target molecular weight is obtained, but the solvent tetrahydrofuran is added in the preparation, the reaction steps are complicated and long, the solvent removal operation is required, the molecular weight of the obtained product is distributed between 1.3 and 1.75, the distribution is wide, the uniformity of the product is poor, the DMC catalyst is used in an amount of 980-1000 ppm, and the defects that the catalyst is large and the performance of a downstream product is poor due to the fact that metal ions remain in the product are also present.

Disclosure of Invention

The invention aims to solve the technical problems of large DMC catalyst dosage, low catalytic activity and high product viscosity in the preparation of polyether ester polyol in the prior art, and provides a preparation method of polyether ester polyol.

In order to solve the technical problems, the technical scheme provided by the invention is as follows: a preparation method of polyether ester polyol sequentially comprises the following steps:

(a) Adding a low molecular weight polyol starter, caprolactone and DMC catalyst into a reaction kettle for homogenization, wherein the dosage of the DMC catalyst in the whole reaction system is 30-150 ppm, and obtaining a material I;

(b) Heating the material I for degassing and dehydrating at 100-140 ℃ for 0.5-1.0 h, and replacing nitrogen until the oxygen content is less than or equal to 100ppm to obtain a material II;

(c) Adding a small amount of propylene oxide into the material II to activate the catalytic reaction, wherein the excitation temperature is 120-130 ℃, the addition amount of the propylene oxide is 2-15% of the total mass of the propylene oxide, and obtaining a material III after the pressure in the reaction kettle is observed to be reduced and stabilized;

(d) Continuously dropwise adding the rest propylene oxide into the material III, wherein the molar ratio of the caprolactone to the total propylene oxide is 1: 1-10, wherein the pressure in the reaction kettle is less than or equal to 0.5MPa in the dripping process, the reaction temperature is 120-140 ℃, the dripping is finished, the internal pressure reaction is continued for 1-4 h, and the internal pressure is less than or equal to 0.1MPa, so as to obtain a material IV;

(e) And vacuumizing the material IV, and removing unreacted monomers to obtain a polyether ester polyol product.

In the above technical scheme, preferably, the functionality of the low molecular weight polyol initiator in the step (a) is 1-6, and the number average molecular weight is 50-2000.

In the above technical scheme, preferably, the functionality of the low molecular weight polyol initiator in the step (a) is 2 to 4.

In the above technical scheme, preferably, the molar ratio of the low molecular weight polyol to caprolactone in the step (a) is 0.01-0.80: 1.

in the above technical scheme, preferably, the DMC catalyst is a cobalt/zinc double metal cyanide complex catalyst, and the DMC catalyst dosage in the whole reaction system is 30-120 ppm.

In the above technical scheme, preferably, the degassing and dehydrating temperature in the step (b) is 100-120 ℃.

In the above technical scheme, preferably, the degassing and dehydrating temperature in the step (b) is 100-110 ℃.

In the above technical solution, preferably, the molar ratio of the caprolactone to the total propylene oxide in the step (d) is 1:1.3 to 6.

In the above technical scheme, preferably, the reaction temperature in the step (d) is 125-135 ℃ and the internal pressure time is 2-4 h.

In the above technical scheme, preferably, the number average molecular weight of the obtained polyether ester polyol is 500-10000.

The preparation method of the polyether ester polyol adopts DMC catalytic ring-opening polymerization process, wherein the low molecular weight polyol, caprolactone and DMC catalyst are homogenized in the same reaction kettle, and no additional storage tank is needed, thus being beneficial to industrialized implementation; moreover, the production process is simple, the reaction time is short, the dosage of the added DMC catalyst is only 30-150 ppm of the total amount of materials, the dosage is small, the product quantity obtained by the unit catalyst in unit time is large, the catalytic activity is high, the production efficiency is improved, the production cost is saved, and meanwhile, the adverse effect on the performance of downstream products caused by a large amount of metal ions remained in the catalyst in the polyether ester polyol product is avoided; the finally prepared polyether ester polyol also has the advantages of low viscosity, narrow molecular weight distribution and few byproducts; in addition, according to the difference of the content of the caprolactone in the molecular chain segment of the polyether ester polyol and the difference of the functionality, the polyether ester polyol product with various performances can be prepared, more optional spaces are provided for polyol selection of downstream polyurethane products, and good technical effects are achieved.

The performance index test method of the polyether ester polyol prepared by the invention comprises the following steps:

number average molecular weight (Mn) and molecular weight distribution (Mw/Mn): the hydroxyl-containing low molecular weight polyol starter referred to herein, and the polyether ester polyol produced, have number average molecular weights (Mn), weight average molecular weights (Mw) and molecular weight distributions (Mw/Mn) determined by GPC, i.e., gel permeation chromatography; when the initiator is composed of only molecules of the same molecular weight as the low molecular alcohol, the molecular weight obtained from the chemical formula is referred to as the number average molecular weight (Mn);

viscosity: GB/T12008.7-2010;

hydroxyl number: GB/T12008.3-2009.

The present invention is further illustrated by, but not limited to, the following examples.

Detailed Description

Low molecular weight polyol initiator:

low molecular weight polyol a: functionality 1, number average molecular weight 74, manufacturer MACKLIN;

low molecular weight polyol B: functionality is 2, number average molecular weight is 400, and manufacturer is Changhua chemical technology Co., ltd;

low molecular weight polyol C: functionality is 3, number average molecular weight is 700, and manufacturer is Changhua chemical technology Co., ltd;

low molecular weight polyol D: functionality is 4, number average molecular weight is 1200, and manufacturer is Changhua chemical technology Co., ltd;

low molecular weight polyol E: functionality is 6, number average molecular weight is 2000, manufacturer is Changhua chemical technology Co., ltd;

polyether diol F: functionality is 2, number average molecular weight is 1400, manufacturer is Changhua chemical technology Co., ltd;

polyether triol TMN-350: functionality is 3, number average molecular weight is 480, and manufacturer is the middle petrochemical Tianjin petrochemical company;

caprolactone: the manufacturer is Allatin;

propylene Oxide (PO): the manufacturer is Hensman;

DMC catalyst: the manufacturer is Changhua chemical technology Co., ltd;

tetrahydrofuran (THF): chromatographic grade, fisher's manufacturer.

[ example 1 ]

A preparation method of polyether ester polyol sequentially comprises the following steps:

(a) Low molecular weight polyol B:450g, caprolactone: 1050g, DMC catalyst: 0.25g was charged into a 5L stainless steel reaction vessel for homogenization, wherein the molar ratio of low molecular weight polyol B to caprolactone was 0.122:1, the DMC catalyst dosage in the whole reaction system is 83.3ppm, and a material I is obtained;

(b) Heating the material I for degassing and dehydrating, wherein the temperature is 105 ℃, the time is 0.5h, and nitrogen is replaced for five times until the oxygen content is less than or equal to 100ppm, so as to obtain a material II;

(c) Slowly adding 100g of propylene oxide into the material II to activate the catalytic reaction, wherein the excitation temperature is 125 ℃, and obtaining a material III after the pressure in the reaction kettle is observed to be reduced and stabilized;

(d) Continuously dripping the rest 1400g of propylene oxide into the material III, wherein the pressure in the reaction kettle is less than or equal to 0.5MPa in the dripping process, the reaction temperature is 125 ℃, the dripping is finished, the internal pressure reaction is continued for 2 hours, and the internal pressure is less than or equal to 0.1MPa, so as to obtain a material IV;

(e) Vacuumizing the material IV to remove unreacted monomers to obtain a polyether ester polyol product, wherein the performance index data are as follows: the functionality is 2, the number average molecular weight (Mn) is 2500, the molecular weight distribution (Mw/Mn) is 1.05, the viscosity at 25 ℃ is 278 mPa.s, propylene oxide and caprolactone monomers are not basically recovered in the process of monomer removal, the reaction is complete, and the mass percentage of caprolactone in the obtained polyether ester polyol product is 35%.

Examples 2 to 5

Examples 2 to 5 were carried out according to the steps of example 1, except that the reaction raw materials, the raw material ratios and the reaction conditions were different, and are specifically shown in table 1; the performance index data of the polyether ester polyol obtained are also shown in Table 1.

TABLE 1 examples 1-5 raw material quality and reaction conditions in the preparation of polyetherester polyols

[ comparative example 1 ]

Referring to the procedure of example 2 in chinese patent CN101243119B, a polyetherester polyol was prepared as follows:

(1) 1000g of polyether glycol F and 2.440g of DMC catalyst as a starter were charged into a 10L stainless steel reactor, nitrogen substitution was performed, and the temperature was raised to 140 ℃;

(2) 50g of propylene oxide is supplied into the reactor under stirring, and the reaction is catalyzed and activated;

(3) Confirming the pressure drop in the reactor, after the catalyst is activated, feeding 300g of propylene oxide and 650g of caprolactone into the reactor at a speed of about 80g/h under stirring, continuously stirring for 1h, keeping the temperature in the reactor at 140 ℃, keeping the stirring speed at 500 revolutions per minute, and carrying out polymerization reaction; the prepared polyether ester dihydric alcohol has the performance index data of Mw/Mn=1.15, mn=2705, the viscosity at 25 ℃ is 889 mPa.s, and the mass percent of caprolactone in the product is 32.5 percent.

[ comparative example 2 ]

The polyetherester polyols were prepared by reference to the procedure of example 2 of U.S. patent No. 5032671a, and are described in detail as follows:

(1) Into a 1L reactor was charged 78.9g of polyether triol TMN-350,0.575g of DMC catalyst and 60mL of tetrahydrofuran;

(2) Mixing caprolactone with propylene oxide to obtain caprolactone/PO mixture containing caprolactone 120g and propylene oxide 377 g;

(3) Purging the reactor with nitrogen several times, then pressurizing to about 5psi, stirring and heating to 90 ℃ for 1.5 hours, adding 37g of caprolactone/PO mixture to the reactor, and activating the catalytic reaction;

(4) After about 1h a pressure drop was observed indicating that the catalyst had been activated, the remaining caprolactone/PO mixture was added over 10h and heated at 90 ℃ for a further 8h;

(5) Cooled, discharged from the reactor, and filtered through celite; removing tetrahydrofuran using a rotary evaporator;

(6) Residual caprolactone monomers are removed by a wiped film evaporator under vacuum at 150 ℃ to obtain polyether ester triol, wherein the performance index data are as follows: the hydroxyl value is 52.8mg KOH/g, mn=3188, mw/Mn=1.71, the viscosity at 25 ℃ is 1419 mPa.s, and the mass percent of caprolactone in the product is 20.8%.

As can be seen from Table 1, the preparation method of polyether ester polyol in examples 1-5 of the invention has simple process steps, is beneficial to industrialized implementation, has small dosage of DMC catalyst, has high catalytic activity in unit time, improves production efficiency, saves production cost, and avoids adverse effect on downstream product performance caused by a large amount of metal ions remained in the catalyst in polyether ester polyol products; meanwhile, compared with comparative example 1, the example 1 has the functionality of 2 and the number average molecular weight of the polyether ester polyol products are similar, but the viscosity of the comparative example 1 at 25 ℃ is 889 mPas and is obviously larger than 278 mPas of the invention; example 2 compared with comparative example 2, both polyether ester polyol products had a functionality of 3 and a similar number average molecular weight, but comparative example 2 had a viscosity of 1419 mPas at 25℃which is significantly greater than 983 mPas of the present invention and a molecular weight distribution of 1.71 which is greater than example 2; therefore, the preparation method of the invention has the advantages of simple process steps, high catalytic activity of the catalyst, low viscosity of the polyether ester polyol product and narrow molecular weight distribution, achieves good technical effects, and can be used in the industrial production of the polyether ester polyol.

Claims (10)

1. A preparation method of polyether ester polyol sequentially comprises the following steps:

(a) Adding a low molecular weight polyol starter, caprolactone and DMC catalyst into a reaction kettle for homogenization, wherein the dosage of the DMC catalyst in the whole reaction system is 30-150 ppm, and obtaining a material I;

(b) Heating the material I for degassing and dehydrating at 100-140 ℃ for 0.5-1.0 h, and replacing nitrogen until the oxygen content is less than or equal to 100ppm to obtain a material II;

(c) Adding a small amount of propylene oxide into the material II to activate the catalytic reaction, wherein the excitation temperature is 120-130 ℃, the addition amount of the propylene oxide is 2-15% of the total mass of the propylene oxide, and obtaining a material III after the pressure in the reaction kettle is observed to be reduced and stabilized;

(d) Continuously dropwise adding the rest propylene oxide into the material III, wherein the molar ratio of the caprolactone to the total propylene oxide is 1: 1-10, wherein the pressure in the reaction kettle is less than or equal to 0.5MPa in the dripping process, the reaction temperature is 120-140 ℃, the dripping is finished, the internal pressure reaction is continued for 1-4 h, and the internal pressure is less than or equal to 0.1MPa, so as to obtain a material IV;

(e) And vacuumizing the material IV, and removing unreacted monomers to obtain a polyether ester polyol product.

2. The process for producing polyether ester polyol according to claim 1, wherein the low molecular weight polyol initiator in the step (a) has a functionality of 1 to 6 and a number average molecular weight of 50 to 2000.

3. The process for preparing a polyetherester polyol of claim 2, wherein the low molecular weight polyol starter in step (a) has a functionality of from 2 to 4.

4. The method of claim 1, wherein the molar ratio of low molecular weight polyol to caprolactone in step (a) is from 0.01 to 0.80:1.

5. the method for preparing polyether ester polyol according to claim 1, wherein the DMC catalyst is a cobalt/zinc double metal cyanide complex catalyst, and the DMC catalyst is used in an amount of 30 to 120ppm in the whole reaction system.

6. The process for producing polyether ester polyol according to claim 1, wherein the degassing and dehydrating temperature in the step (b) is 100 to 120 ℃.

7. The process for producing polyether ester polyol according to claim 1, wherein the degassing and dehydrating temperature in the step (b) is 100 to 110 ℃.

8. The method of claim 1, wherein the mole ratio of the caprolactone to the total propylene oxide in the step (d) is 1:1.3 to 6.

9. The method for preparing polyether ester polyol according to claim 1, wherein the reaction temperature in the step (d) is 125-135 ℃ and the internal pressure time is 2-4 hours.

10. The method for preparing polyether ester polyol according to claim 1, wherein the number average molecular weight of the polyether ester polyol product is 500 to 10000.