JP3118299B2 - Method for producing polyester carbonate polyol - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a polyester carbonate polyol. For more information,
The present invention relates to a method for producing a polyester carbonate polyol by esterification and transesterification of ethylene carbonate and an organic dicarboxylic acid with a polyhydric alcohol. The polyester carbonate polyol obtained by the production method of the present invention is useful as a raw material for polyurethane.

[0002]

2. Description of the Related Art Polyether-based, polyester-based and polycarbonate-based soft segments have been conventionally known.

[0003] For example, a polycarbonate-based polyurethane is produced using a polycarbonate polyol as one of the starting compounds. This polycarbonate polyol is produced by reacting a carbonate compound as a carbonate source with a polyhydric alcohol.As the carbonate source, it is inexpensive, and there is no residual high-boiling by-product in the produced polycarbonate polyol. Ethylene carbonate is industrially
It is considered suitable. In this method using ethylene carbonate, it is necessary to distill out ethylene glycol generated during the transesterification reaction with the polyhydric alcohol out of the system during the reaction, but ethylene carbonate can azeotrope with ethylene glycol. Therefore, there is a problem that ethylene carbonate is lost simultaneously with the distillation of ethylene glycol. However, this problem is also solved by allowing an azeotropic solvent of ethylene glycol to be present in the reaction system and removing the ethylene glycol out of the system as an azeotropic mixture with the azeotropic solvent (JP-A-51-14).
No. 4492).

On the other hand, recently, as a polyurethane which supplements the disadvantages of the polyester type and the polycarbonate type and has the advantages of both, a polyurethane using a polyester carbonate polyol as a soft segment has been proposed.
For example, polyurethane using polyester carbonate diol simultaneously satisfies flexibility, durability, cold resistance, and mechanical performance, and is particularly useful for elastic fibers.

[0005] Polyester carbonate polyols
The polyester polyol and the polycarbonate polyol can be produced by applying a usual method used for producing the same, basically as it is. For example, a polyester compound polyol can be obtained by charging a carbonate compound, an organic dicarboxylic acid, and a polyhydric alcohol into a reactor at one time, and allowing esterification and transesterification to proceed in parallel.

[0006]

According to the study of the present inventors, the above-mentioned method for producing a polycarbonate polyol using ethylene carbonate and an azeotropic solvent includes a method for producing both a polycarbonate group and an ester group in a molecular main chain. When applied to a method for producing a polyester carbonate polyol containing a random arrangement and reacting a mixture of ethylene carbonate, a polyhydric alcohol and an organic dicarboxylic acid, the reaction between the dicarboxylic acid and the polyhydric alcohol proceeds smoothly, but azeotropic Even if various solvents are selected, ethylene carbonate is distilled off to a considerable extent and is lost.In addition, the reaction itself is significantly slowed down, and even if the reaction time is extremely long, part of the ethylene carbonate remains unreacted. In addition to the low yield based on ethylene carbonate, It has been found that problems such as the molar ratio of Boneto group can not be reproduced is present. In the polyester carbonate polyol, since the abundance ratio of the ester group and the carbonate group greatly affects the properties of the polyurethane, it is necessary to control the reaction conditions so that the desired abundance ratio is strictly reproduced. Therefore, it is difficult to say that the above method is suitable for an industrial manufacturing method.

An object of the present invention is to control the molar ratio of ester groups to carbonate groups to a desired value with good reproducibility, to use a high raw material utilization rate, and to obtain an industrially suitable polyester carbonate having a high reaction rate. It is to provide a method for producing a polyol.

[0008]

According to the present invention, the above object is achieved by reacting ethylene carbonate with a polyhydric alcohol having 3 or more carbon atoms until the conversion of the ethylene carbonate becomes 80% or more. Producing a polyester carbonate polyol, characterized in that the reaction mixture obtained is mixed with an organic dicarboxylic acid and reacted, and during the reaction, ethylene glycol produced is removed from the reaction system as an azeotropic mixture with a solvent. This is achieved by providing a method.

According to the invention, the production of the polyester carbonate polyol is carried out in two stages. In the first step, a polyhydric alcohol having 3 or more carbon atoms and ethylene carbonate are azeotropically mixed with ethylene carbonate in a molar ratio of preferably 15: 1 to 1: 2 in the presence of an ethylene glycol azeotropic solvent. The transesterification reaction is carried out while distilling out of the system together with the solvent. As the reaction temperature in the first step, from the viewpoint of achieving a sufficient reaction rate,
120 ° C. or higher is preferable, and 140 ° C. or higher is more preferable. On the other hand, regarding the upper limit of the reaction temperature, from the viewpoint of preventing the loss due to the decomposition of ethylene carbonate, it is preferable that the reaction temperature does not exceed 260 ° C. Further, the loss due to the distillation of ethylene carbonate out of the reaction system is also prevented. It is more preferable that the temperature does not exceed 240 ° C. from the viewpoint of preventing the loss of 220 ° C. from the decomposition and distillation of ethylene carbonate, and 220 ° C. It is even more preferred not to exceed.

In the reaction of the first step, ethylene carbonate may be charged to the reaction system in its entirety from the beginning.
Since ether bonds may be mixed in a small proportion into the molecules of the polyester carbonate polyol as the final product, it is preferable to continuously feed the reaction system from the viewpoint of preventing such mixing. In addition, it is preferable to add the polyhydric alcohol to the reaction system in its entirety from the beginning, since the apparent reaction rate is increased and the reaction time is shortened.

The second step is started by mixing the obtained reaction mixture with an organic dicarboxylic acid and reacting when the reaction rate of ethylene carbonate reaches 80% or more in the reaction of the first step. You.

The conversion of ethylene carbonate in the present invention is the percentage of the actual consumption of ethylene carbonate in relation to the theoretical consumption of ethylene carbonate in a transesterification reaction to give a polycarbonate which can occur between the used ethylene carbonate and the polyhydric alcohol. . The reaction rate of ethylene carbonate can be determined from the amount of ethylene glycol distilled out of the reaction system.
Is more desirable because it is more accurately determined. Proton NMR is measured according to a commonly used method by dissolving a sample in a non-resonant solvent such as deuterated chloroform, and measuring based on an internal standard such as tetramethylsilane. Taken. Ethylene carbonate has a methylene peak characteristically present at a δ value of around 4.5 ppm, and the area intensity of this peak is compared with that of a reference peak such as a polyhydric alcohol peak or a separately inserted internal standard substance peak. Thus, the reaction rate of ethylene carbonate is accurately calculated.

The point where the reaction rate of ethylene carbonate, that is, the consumption rate is 80% or more, is the starting point of the second step. At this time, the reaction mixture obtained in the first step is charged with the organic dicarboxylic acid in total or continuously. To the reaction system. When the organic dicarboxylic acid is reacted at a reaction rate lower than 80%, the reaction of ethylene carbonate is slowed down, and the reaction rate at the final point is also lowered. As a result, unreacted ethylene carbonate remains and the ester group of the polyester carbonate polyol is reduced. Not only does the molar ratio of the carboxylic acid to the carbonate group greatly deviate from the desired one, but also the yield decreases. From the viewpoint of particularly increasing the utilization rate and reaction rate of the used ethylene carbonate, the starting point of the second stage is preferably a point in time at which the reaction rate of ethylene carbonate is 90% or more.

The reaction temperature employed in the second step is from 120 to 26 from the viewpoint of obtaining the desired polyester carbonate polyol in a short reaction time while suppressing decomposition.
It is preferably in the range of 0 ° C, 140 to 240 ° C
Is more preferably within the range.

In the second stage, both esterification and transesterification substantially occur. The degree of the esterification can be easily determined by measuring the carboxylic acid end group, that is, the acid value of the reaction mixture. Can be recognized. From the viewpoint of accelerating the reaction, it is preferable that water generated by the esterification reaction be distilled off alone or continuously from the reaction system in the form of an azeotrope with a solvent.

In the present invention, the main purpose of causing the solvent to be present in the reaction system is to selectively remove the formed ethylene glycol out of the reaction system in the form of an azeotrope. It is not particularly necessary for the solvent to be present in the reaction system when it has disappeared. Therefore, in the latter half of the second stage, preferably, when the reaction rate of ethylene carbonate becomes 95% or more, the reaction may be carried out while distilling off the solvent from the reaction system.

In the latter half of the second stage, the reaction is usually carried out while distilling off excess low-boiling substances such as polyhydric alcohols and solvents under reduced pressure to reach the desired molecular weight of the produced polyester carbonate polyol. . The molecular weight of the polyester carbonate polyol can be easily measured by a terminal hydroxyl group determination method or the like.

The polyhydric alcohol having 3 or more carbon atoms used in the production method of the present invention is at least one hydroxy compound such as an aliphatic diol, a cycloaliphatic diol and a trihydric or higher polyhydric alcohol. Examples of the aliphatic diol include 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, and 3-methyl-1,5-
Pentanediol, 1,6-hexanediol, 1,7
-Heptanediol, 1,8-octanediol, 2-
Methyl-1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,12-dodecanediol, neopentyl glycol, and the like,
As the cycloaliphatic diol, 1,3-cyclohexanediol, 1,4-dimethylolcyclohexane and the like are used. Further, when producing a polyester carbonate polyol having a valence of more than two, a trihydric or higher polyhydric alcohol such as trimethylolpropane or decanetriol is used in accordance with the desired number of hydroxyl groups that the polyol should have. Need to be used as at least a part of the polyhydric alcohol.

Examples of the organic dicarboxylic acid for producing the polyester carbonate polyol used in the present invention include aliphatic dicarboxylic acids such as glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid and dodecanedicarboxylic acid. Examples thereof include aromatic dicarboxylic acids such as phthalic acid, terephthalic acid, and isophthalic acid, which can be arbitrarily selected according to physical properties required for a final product such as a polyurethane using a polyester carbonate polyol. These dicarboxylic acids can be used alone or in combination of two or more. The organic dicarboxylic acid can be supplied to the reaction system in any form such as a solid, a molten liquid, and a solution.

In the present invention, a solvent that azeotropes with ethylene glycol is present in the reaction system in order to remove generated ethylene glycol outside the reaction system during the reaction. Such a solvent that azeotropes with ethylene glycol does not adversely affect the reaction, is capable of forming an azeotropic mixture containing ethylene glycol in a high proportion in terms of the ability to remove ethylene glycol, and conforms to a suitable reaction temperature. 100-26
Those satisfying the conditions of having a boiling point of 0 ° C. and being substantially insoluble in ethylene glycol are preferable in that they can be easily collected and recycled. Further, a solvent having not only ethylene glycol but also a property capable of forming an azeotrope with water is more preferable in that the esterification reaction accompanying the generation of water in the second step can be promoted. Examples of such preferred solvents include toluene, xylene, cumene,
Pseudocumene, mesitylene, tetramethylbenzene,
Aromatic hydrocarbons such as cymene, diethylbenzene, diisopropylbenzene and the like can be mentioned. Above all, pseudocumene is preferable in that ethylene glycol removal ability is particularly high, and cumene or xylene is preferable in that the above conditions are highly satisfied and the cost is low. In addition,
In the present invention, the solvent azeotropic with ethylene glycol is usually present in the reaction system in an amount of 5% or more based on the total weight of the ethylene carbonate and the polyhydric alcohol used. From the viewpoint of preventing the incorporation of an ether bond into the molecule of the obtained polyester carbonate polyol, it is preferable that a solvent having a weight of 10% or more is present in the reaction system. For the purpose of achieving a sufficient reaction rate, it is desirable that the amount of the solvent not exceed 1000% on the same basis.

The reaction according to the invention proceeds in the absence of a catalyst, but is promoted by the catalyst. Suitable catalysts include metals such as lithium, sodium, titanium, tin and magnesium, and alkoxides thereof. Particularly preferred are organometallic compounds of metals such as titanium and tin.

The polyester carbonate polyol obtained in the present invention has an average of two or more hydroxyl groups at the molecular terminals, and has an ester bond (-CO-O-) and a carbonate bond (-O-CO-O-). Both are usually in the molecular backbone
It is a polymer compound introduced in a random sequence. Suitable polyester carbonate polyol varies depending on required physical properties such as polyurethane obtained as a final product,
Generally, the ratio of the number of ester bonds / the number of carbonate bonds is 90
/ 10-20 / 80, and the number average molecular weight is 500-3.
500.

[0023]

The present invention will be described in detail with reference to the following examples. In Examples and Comparative Examples, ¹ H-NMR, the reaction rate of ethylene carbonate, the E / C ratio (the ratio of the number of ester bonds / the number of carbonate bonds), the acid value, and the hydroxyl value (number average molecular weight of the polyester carbonate polyol) Used to determine) and the degree of randomness were measured by the following methods.

¹ H-NMR Measurement was performed using GSX270 (270 MHz) manufactured by JEOL Ltd. with tetramethylsilane as an internal standard.

Ethylene carbonate reaction rate Diphenylmethane (methylene group chemical shift: δ 3.9 ppm) was separately added to the reaction solution as a reference substance.
70 MHz ¹ H-NMR (solvent: CDCl ₃ ) was measured,
It was calculated by comparing the areal intensity of the methylene group signal of ethylene carbonate having a δ value of 4.5 ppm with the areal intensity of the methylene group signal of the diphenylmethane.

Ratio of the number of ester bonds / the number of carbonate bonds (E / C ratio) 270 MHz ^{1 of} polyester carbonate polyol
H-NMR (solvent: CDCl ₃ ) was measured, and the E / C ratio of the polyester carbonate polyol was determined according to the following equation.

E = [2b / (a + b)] × 100 C = [(ab) / (a + b)] × 100

(Where a is δ 4.27 to 4.00 pp
m signals _{(-CH 2 OC (= O)} O- and -CH ₂
Represents the integrated intensity of OC (= O)-), where b is δ 2.29p
pm signal representing the integrated intensity of the _{(-CH 2 C (= O)} O-))

Acid value A sample of the polyester carbonate polyol was accurately measured and dissolved in acetone. Using phenolphthalein as an indicator, titration was performed with a methanol solution of potassium hydroxide. The acid value was calculated by the following equation.

Acid value (mgKOH / g) = [f × (a−
b) × 5.61] / S

(Where a represents the required titration amount (ml), b represents the required titration amount of the blank (ml), f represents the factor of a 0.1 N potassium hydroxide methanol solution, and S represents Represents the weight (g) of the sample)

Hydroxyl value A polyester carbonate polyol sample was accurately measured and dissolved in an esterifying agent. 100 ℃
The mixture was heated in an oil bath with stirring for 1 hour, cooled to room temperature, the excess esterifying agent was decomposed with distilled water, and back titration was performed to determine the hydroxyl value according to the following formula.

Hydroxyl value (mgKOH / g) = acid value + [f
× (ba) × 28.05] / S

(Where a represents the required amount of titration (ml), b represents the required amount of blank titration (ml), f represents the factor of a 0.5 N aqueous potassium hydroxide solution, and S represents the sample. The acid value represents the acid value (mgKOH / g) of the sample.

The degree of randomness of the polyester carbonate polyol is as follows:
500 MHz ¹ H-NMR (using JEOL GX-500) was measured, and 3-methyl-1,
It was determined by analyzing the signal of the methyl group of the component derived from 5-pentanediol. The following five types of constituent parts derived from 3-methyl-1,5-pentanediol are present in the polymer molecule. Table 1 shows the chemical structures of the five types of constituent parts and the chemical shift values (δ values) of the signals of the respective methyl groups.

[0036]

[Table 1]

These signals were separated, and the area intensities of the signals of the respective methyl groups of the structures a, b and c in Table 1 were determined, and the degree of randomness was determined by the following equation.

Randomness = [(0.5 × B) / (A +
0.5 × B)] + [(0.5 × B) / (C + 0.5 ×
B)]

(Where A represents the area intensity of the signal of the methyl group of the structure a, B represents the area intensity of the signal of the methyl group of the structure b, and C represents the area intensity of the signal of the methyl group of the structure c. Represent)

The chemical substances used may be indicated by the abbreviations shown in Table 2.

[0041]

[Table 2]

Example 1 A 1000-ml three-necked flask equipped with a Higrew-type fractionating tube (φ30 × H700 mm) equipped with a condenser at the top via a layer separation tube, a stirring blade and a dropping funnel was used as a reactor.

The MPD (165 g, 1.4 mol) was added to the flask.
l) and pseudocumene (pCu, 145 g) were charged and the mixture was heated in an oil bath (205 ° C.) with stirring at a speed of 500 rpm. Solvent pC
When u begins to reflux at a rate of about 0.5 kg / h with a layer separation tube at the top of the fractionation tube (pCu retained here is 27 g at maximum) and a cooler, EC (22 g, 0.25 mol) is removed. Add all at once from the dropping funnel, and then add E from the dropping funnel.
C (22 g, 0.25 mol) was added dropwise over 3 hours in a molten state. During this time, the solvent was refluxed at a rate of about 0.5 kg / h, generated intermittently by the EC reaction, and intermittently extracted ethylene glycol which was azeotropic with pCu and accumulated in the layer separation tube. The reaction continues even after the completion of EC dropping,
When the EC reaction rate reached 90% (after 6 hours), AZ
(94 g, 0.5 mol; charged composition (value when all reacted): number of carbonate bonds / number of ester bonds = 33
/ Equivalent) was added all at once as a solid. Thereafter, water generated by the AZ esterification reaction and azeotropic with pCu and accumulated in the layer separation tube was intermittently extracted. A
Two hours after Z addition, the catalyst tetraisopropyl titanate (15 ppm based on the total weight of MPD, EC and AZ used) was added. Then, normal pressure (up to 3 hours after AZ addition) and 100 mmHg (3 hours after AZ addition)
The pCu was distilled off (from the hour to the 5th hour). At this point, the acid value of the reaction mixture was 0.1 or less. At this time, the reaction rate of EC had already reached 100%. After removing the entire amount of pCu, excess M was added at 1 mmHg.
The PD was distilled off to obtain a polyester carbonate diol having a number average molecular weight of 2680 (having the following ¹ H-NMR), which has both an ester bond and a carbonate bond in the molecule and a hydroxyl group at both ends. .

¹ H-NMR (270 MHz, CDC
l ₃ ), (multiplicity, relative intensity): δ 4.27-4.00
(M, 22.0), δ 3.7 (m, 2.0), δ 2.2
9 (t, 11.2), δ 1.83-1.38 (m, 4
5.5), δ 1.32 (m, 19.5), δ 0.96
(M, 18.0)

Table 3 summarizes the production conditions, composition, molecular weight and the like of the obtained polyester carbonate diol.
As is clear from Table 3, the ratio of the number of ester bonds in the molecule of the polyester carbonate diol to the number of carbonate bonds was 68/32, which was almost a value close to the composition ratio of the charged raw materials. No ether bond due to a side reaction of ethylene carbonate was observed. Further, the degree of randomness of the ester bond and the carbonate bond was 0.95, which was almost close to 1, and both bonds were almost completely introduced at random.

Comparative Example 1 The same reactor as in Example 1 was used. Further, the charged composition was the same as in Example 1.

When the solvent pCu starts refluxing at a rate of about 0.5 kg / h in the layer separation tube at the top of the fractionating tube and the condenser, EC (molten state) and AZ (molten state) are simultaneously conducted for 3 hours each. And dropped. During this time, the solvent is 0.5kg
/ H, reflux at a rate of about / h, produced by the reaction of EC,
Ethylene glycol and water azeotroped with pCu and accumulated in the layer separation tube were intermittently extracted. At the end of AZ dropping, tetraisopropyl titanate (15 ppm) as a catalyst
Was added. The reaction was continued after completion of the dropwise addition of EC and AZ. Seven hours after the start of the reaction, the acid value became 0.1 or less, and the reaction of AZ was substantially completed.
It has been consumed since 8%. Start reaction 1
Four hours later, pCu was distilled off at normal pressure for 1 hour and then at 100 mmHg for 1 hour. 1mm after pCu distillation
It was distilled off excess MPD in Hg, several polyester carbonate diol having an average molecular weight 2590 ⁽¹ H-NMR are as follows) was obtained.

¹ H-NMR (270 MHz, CDC
l ₃ ), (multiplicity, relative intensity): δ4.27-4.00
(M, 22.0), δ 3.7 (m, 1.8), δ 2.2
9 (t, 13.2), δ 1.83-1.38 (m, 4
4.5), δ 1.32 (m, 18.3), δ 0.96
(M, 17.2)

Table 3 summarizes the production conditions, composition, molecular weight and the like of the obtained polyester carbonate diol.
The polyester carbonate diol has hydroxyl groups at both molecular ends, and has ester bonds and carbonate bonds substantially randomly introduced (degree of randomness:
0.97), but the ratio of the number of ester bonds to the number of carbonate bonds in the molecule is 80/20, and the charged value (6
7/33).

Comparative Example 2 Polyester carbonate diol was produced in the same manner as in Comparative Example 1 except that AZ was charged all at once in the initial stage of the reaction. Table 3 shows the production conditions and results. Also in this method, a polyester carbonate diol having a hydroxyl group at the molecular terminal and having ester bonds and carbonate bonds substantially randomly introduced (randomness: 1.02) was obtained, but the final reaction attainment rate of ethylene carbonate was obtained. Remained at 87%. Therefore, the ratio of the number of ester bonds to the number of carbonate bonds is 82/18, and the charge value (6
7/33).

Examples 2 to 5 Polyester carbonate diols were produced using the same reaction apparatus as used in Example 1 and by the composition and production method shown in Table 3 or Table 4. As shown in Tables 3 and 4, the ultimate reaction rate of ethylene carbonate was almost 100%, and the E / C was very close to that of the charged amount in each case.

Comparative Example 3 Using the same reactor as used in Example 1, polyester carbonate diol was produced according to the composition and production method shown in Table 4. The final reaction rate of ethylene carbonate is only 92%, and the E / C ratio is 60/40.
The value was significantly different from the charged value (50/50).

[0053]

[Table 3]

[0054]

[Table 4]

[0055]

As is clear from the above examples, according to the production method of the present invention, the reaction rate of ethylene carbonate can be increased, and a polyester carbonate polyol having a desired monomer composition ratio can be produced with good reproducibility. It is possible to do. Therefore, the present invention is suitable as an industrial production method of a polyester carbonate polyol.

Claims (1)

(57) [Claims] 1. The reaction of ethylene carbonate with a polyhydric alcohol having 3 or more carbon atoms and a reaction rate of the ethylene carbonate of 8 or more.
0% or more, and then reacting the resulting reaction mixture with an organic dicarboxylic acid. During the reaction, ethylene glycol formed during the reaction is removed from the reaction system as an azeotrope with a solvent. A method for producing a polyester carbonate polyol.