JP3235909B2 - Method for producing lactone-based polyester polyol - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a polyester polyol by ring-opening polymerization of a lactone. More specifically, the present invention relates to a polyester polyol obtained by ring-opening polymerization of an optionally substituted δ-valerolactone using a compound having two active hydrogen atoms such as ethylene glycol and butanediol as an initiator. And a method for producing the same.

[0002]

2. Description of the Related Art A polyester polyol having hydroxyl groups at both ends obtained by ring-opening polymerization of a substituted or unsubstituted δ-valerolactone using a compound having two active hydrogen atoms as an initiator is ε-caprolactone. Polycaprolactone obtained by ring-opening polymerization of
Like the polyester polyol obtained by polycondensation of a dicarboxylic acid and a diol, the compound is a useful compound as a raw material for a polyurethane or a polyester elastomer.

[0003] Among them, poly (β-methyl-δ-) obtained by ring-opening polymerization of β-methyl-δ-valerolactone.
Valerolactone) polyol (hereinafter abbreviated as PMVL) is a liquid having fluidity at room temperature, and is far superior to other polyester polyols in terms of ease of handling. Further, it is useful as a raw material for providing a soft polyurethane and polyester elastomer having excellent hydrolysis resistance, and is produced on an industrial scale.

[0004]

The reaction for obtaining a polyester polyol by ring-opening addition of a substituted or unsubstituted δ-valerolactone to a compound having two active hydrogen atoms such as ethylene glycol and butanediol is usually carried out. , Sulfuric acid, mineral acids such as phosphoric acid, alkali metals such as lithium, sodium and potassium, hydroxides, carbonates and bicarbonates of alkali metals or alkaline earth metals such as sodium hydroxide, potassium carbonate and calcium oxide, n
Alkyl metal compounds such as -butyllithium, organic acids such as p-toluenesulfonic acid, acidic ion exchange resins, solid acids such as activated clay, tetraisopropyl titanate, tetrabutyl titanate, tetraphenyltin, tetraoctyltin, diphenyltin dilaurate In the presence of a catalyst such as an organic metal. (JP-A-60-55026, JP-A-64-85968) Generally, when the produced polymer is thermally stable, there is no problem even if the catalyst used in the reaction remains. . However, the polyester polyol obtained according to the above-mentioned known method is relatively thermodynamically unstable because it contains a substituted or unsubstituted δ-valerolactone in the molecule, and therefore, the catalyst used in the reaction is used. Residues may impair stability during storage or cause undesirable side reactions when subsequently producing a polymeric substance using the polyester polyol. To prevent this, it is conceivable to remove the catalyst substance by washing the obtained polyester polyol with water or the like, but it is not easy to remove the catalyst component.

When a polyester polyol is produced using a solid acid catalyst such as an acidic ion exchange resin or activated clay, the catalyst can be easily removed by filtration.
Since it is difficult to avoid elution of a trace amount of impurities, the stability of the polyester polyol is also impaired during storage, or an undesired side reaction is caused when a polymer substance is produced by a subsequent polymerization reaction.

Therefore, for example, Japanese Patent Application Laid-Open No. 60-55026
In the case of producing PMVL using a catalyst described in Japanese Patent Application Laid-open No.
After the reaction is carried out using a solvent that dissolves MVL and is immiscible with water, the reaction solution is washed several times with water, or the reaction is carried out in the absence of a solvent. And then separating the solution, and preferably removing the solvent and water under reduced pressure.

However, this method requires a special facility for removing the catalytic substance, or has a drawback such as the necessity of treating an enormous amount of wastewater having a high COD value when removing the catalytic substance. have. Moreover, this method requires equipment for recovering, purifying and storing the solvent used.

The advantage of the ring-opening addition polymer is that unlike the polycondensate, the amount of water contained in the product is small because water is not produced as a by-product during the production, and the dehydration operation at the time of use is not required. However, washing the product with water also eliminates this advantage.

It is an object of the present invention to solve these problems and to provide a method for industrially advantageously producing a polymer from a substituted or unsubstituted δ-valerolactone.

[0010]

Conventionally, when a ring-opening addition reaction of a substituted or unsubstituted δ-valerolactone is carried out using a tertiary amine compound catalyst such as pyridine or quinoline, the reaction is It was not expected to happen. (Lecture on Polymerization Reaction 7, written by Takeo Saegusa) As a result of intensive studies, the present inventors have found that a tertiary amine compound having a pKa value of 11 or more and having no active hydrogen in the molecule is used. Not only does the ring-opening addition reaction of substituted or unsubstituted δ-valerolactone proceed at an industrially satisfactory reaction rate, but also distillation from a polymer containing substituted or unsubstituted δ-valerolactone as one component. It has been found that the catalyst component can be removed more easily, and the present invention has been completed.

That is, in the present invention, a tertiary amine compound having a pKa value of 11 or more and having no active hydrogen in the molecule is represented by the general formula (1) HO-R ¹ -OH (1) Wherein R ¹ represents a hydrocarbon group having 2 to 10 carbon atoms in the main chain, which may be substituted with a lower alkyl group.) With a substituted or unsubstituted δ-valerolactone by ring-opening addition Provided is a method for producing a lactone-based polyester polyol characterized by polymerizing.

Specific examples of the tertiary amine compound used in the present invention include 1,8-diazabicyclo
[ 5.4.0 ] undecene-7 (hereinafter abbreviated as DBU). The preferred amount of the tertiary amine compound used is 0.001 to 10% by weight, preferably 0.01% by weight, based on the weight of the substituted or unsubstituted δ-valerolactone.
1 to 2% by weight.

In the present invention, there are a number of glycols represented by the general formula (1), and specific examples thereof include ethylene glycol, propylene glycol, and 2-glycol.
Methyl-1,3-propanediol, 1,4-butanediol, 1,3-butanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,
6-hexanediol, 1,8-octanediol, 2
-Methyl-1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, neopentyl glycol and the like.

The δ-valerolactone used in the present invention may be substituted, and examples of the substituent in this case are a lower alkyl group such as a methyl group and an ethyl group. Specific examples of δ-valerolactone having these substituents include β-methyl-δ-valerolactone, β-ethyl-
δ-valerolactone, γ, γ-dimethyl-δ-valerolactone and the like.

In the method of the present invention, the molecular weight of the obtained polymer is arbitrarily adjusted by adjusting the molar ratio of the substituted or unsubstituted δ-valerolactone to the glycol represented by the general formula (1). It is possible.

The reaction according to the present invention is usually carried out in an atmosphere of an inert gas such as nitrogen, helium or argon. In carrying out this reaction, it is desirable that the substituted or unsubstituted δ-valerolactone and glycol have as low a water content as possible. Similarly, it is desirable to keep the water content of the tertiary amine compound as low as possible.

This reaction is usually carried out in the presence or absence of a solvent at a temperature of -20 ° C. or higher.
Since valerolactone is not always thermally stable, it is better to select a temperature condition that does not exceed 200 ° C.
More preferable temperature conditions are 20 ° C to 80 ° C.

This reaction is usually carried out without using a solvent, but can be carried out using a solvent. Solvents that can be used for this purpose are organic solvents having no active hydrogen, specifically, benzene, toluene, aromatic hydrocarbons such as xylene, diethyl ether, tetrahydrofuran,
Examples thereof include ethers such as dioxane, and halogenated hydrocarbons such as dichloromethane and chloroform. If these solvents are also used, it is desirable to reduce the water content as much as possible prior to use.

In the present invention, the reaction mixture obtained in the reaction can be used as it is as a starting material for the next reaction. However, the catalyst and unreacted substituted or unsubstituted δ-valerolactone are removed and substituted with glycol. Alternatively, it is desirable to purify and use an unsubstituted δ-valerolactone adduct. The treatment of the reaction mixture can be performed, for example, by treating the reaction mixture as it is under reduced pressure using a thin film evaporator. The unreacted substituted or unsubstituted δ-valerolactone and the tertiary amine compound recovered during the treatment can be directly introduced into the next polymerization system.

The method for producing a lactone-based polyester polyol according to the present invention can be widely applied not only when the initiator is a glycol, but also when the compound has a hydroxyl group such as a monoalcohol or a triol.

Hereinafter, the present invention will be described in detail with reference to examples. Example 1 A 500-ml separable flask equipped with a thermometer, a dropping funnel, a stirrer, and a gas inlet / outlet was sufficiently replaced with dry nitrogen gas, and then 10.4 g of ethylene glycol previously dehydrated in the flask and dehydrated in advance. 400 g of β-methyl-δ-valerolactone was charged and immersed in a 30 ° C. bath with stirring under a nitrogen atmosphere.
Thereafter, 8 g of 1,8-diazabicyclo [ 5.4.0 ] undecene-7 previously dehydrated from the dropping funnel was used.
(Manufactured by San Apro) was added immediately. After completion of the dropwise addition, stirring was further continued at 30 ° C to 35 ° C for 24 hours. The reaction mixture becomes a viscous liquid and the β-methyl-δ
-Valerolactone was analyzed by liquid chromatography and found to be 52.8 g.

[0022] Using the obtained polymer wiped film evaporation apparatus, 180 ° C., and treated under the following conditions 1 torr, to give a liquid 335g viscous colorless transparent.

When measured by ¹ H-NMR, it was confirmed from the chemical shift that this liquid was a polyester polyol obtained by ring-opening addition polymerization of β-methyl-δ-valerolactone to ethylene glycol.

This has a hydroxyl value of 56.3 mg KOH.
/ G and an acid value of 0.5 mgKOH / g, the molecular weight was 1975.

Further, from the results of elemental analysis, the residual N content was 0.1%.
02%. Example 2 After thoroughly replacing a 500 ml separable flask equipped with a thermometer, a dropping funnel, a stirrer, and a gas inlet / outlet with dry nitrogen gas, 15 g of 1,4-butanediol previously dehydrated was added to the flask. 400 g of dehydrated δ-valerolactone was charged and immersed in a bath at 60 ° C. with stirring under a nitrogen atmosphere. After a while
From the dropping funnel, 4 g of 1,8-diazabicyclo [ 5.4.0 ] undecene-7 (manufactured by San Apro Co.), which had been dehydrated in advance, was quickly added. After the completion of dropping, the temperature is further increased to 60 ° C
Stirring was continued at 65 ° C. for 24 hours. The reaction mixture became a viscous liquid, and δ -valerolactone in the polymer was analyzed by liquid chromatography to find that it was 79.6 g.

[0026] Using the obtained polymer wiped film evaporation apparatus, 180 ° C., and treated under the following conditions 1 torr, to give a liquid 314g viscous colorless transparent.

When measured by ¹ H-NMR, it was confirmed from the chemical shift that the liquid was a polyester polyol obtained by ring-opening addition polymerization of 1,4-butanediol with δ-valerolactone.

This has a hydroxyl value of 56.5 mg KOH
/ G and an acid value of 0.5 mgKOH / g, the molecular weight was 1970.

Further, from the results of elemental analysis, the residual N content was 0.1%.
02%. Comparative Example After sufficiently replacing a 500 ml separable flask equipped with a thermometer, a dropping funnel, a stirrer, and a gas inlet / outlet with dry nitrogen gas, 11 g of ethylene glycol previously dehydrated and β-methyl dehydrated beforehand were added to the flask. -Δ-valerolactone was charged with 425 g,
It was immersed in a bath at 60 ° C. with stirring under a nitrogen atmosphere. Thereafter, 1 ml of a 25% n-butyllithium hexane solution (manufactured by Nippon Alkali Aluminum Co., Ltd.) was quickly added from the dropping funnel. After completion of the dropping, heat generation was observed, but stirring was continued for another 2 hours after the internal temperature reached 60 ° C to 65 ° C.

The reaction mixture became a viscous liquid, and β-methyl-δ-valerolactone in the polymer was analyzed by liquid chromatography to find that it was 78.6 g. 500 ml of toluene was added to the obtained polymerization solution, and 250 ml of water was added.
And washed three times. Waste water generated at the time of this operation is COD 1
Since it was as high as 880 ppm, it was incinerated.

[0031] After the solution after washing with water was distilled off and toluene by a rotary evaporator, using a wiped film evaporation apparatus, 180 ° C., and treated under the following conditions 1 torr,
321 g of a colorless and transparent viscous liquid was obtained. The recovered toluene was incinerated because the acid value was as high as 0.5 KOHmg / g.

The liquid was measured by ¹ H-NMR, and it was confirmed from the chemical shift that the liquid was a polyester polyol obtained by ring-opening addition polymerization of ethylene glycol with β-methyl-δ-valerolactone.

This has a hydroxyl value of 56.0 mg KOH
/ G and an acid value of 0.3 mgKOH / g, the molecular weight was 1993. Further, the Li content was 0.1 ppm or less according to the atomic absorption method.

[0034]

Industrial Applicability According to the present invention, the reaction of ring-opening addition-polymerization of a substituted or unsubstituted δ-valerolactone to glycol is carried out in the presence of a specific tertiary amine compound, thereby achieving industrial satisfaction. And the catalyst component can be easily removed from the lactone-based polyester polyol, which is a polymer, by distillation, so that the stability of the lactone-based polyester polyol decreases during storage, or Can be prevented from causing an undesirable side reaction when producing a polymer substance by the polymerization reaction.

Claims (2)

(57) [Claims] 1. A with a pKa value of 11 or more, and the presence of a tertiary amine compound having no active hydrogen in its molecule, in the general formula ^{(1) HO-R 1 -OH} (1) ( wherein, R ¹ Represents a hydrocarbon group having 2 to 10 carbon atoms in the main chain which may be substituted with a lower alkyl group.), And subjecting the substituted or unsubstituted δ-valerolactone to ring-opening addition polymerization. A method for producing a lactone-based polyester polyol. 2. The method according to claim 1, wherein the substituted or unsubstituted δ-valerolactone is β-methyl-δ-valerolactone.