JPH08169943A - Method for producing ester polyol - Google Patents

Abstract

(57) [Summary] [Structure] Addition of a specific amount of alkylene oxide to a hydroxycarboxylic acid containing a carboxylic acid cyclic compound and a polyvalent active hydrogen compound at a reaction temperature of 80 to 120 using a specific amine compound as a catalyst. C, then 120-150
Perform at ℃. [Effect] By controlling the acid value, viscosity, addition amount of alkylene oxide, etc., an ester polyol having good quality as a resin for producing rigid polyurethane foam and giving good physical properties to the rigid polyurethane foam can be obtained. Was given.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing an ester polyol for producing polyurethane. More specifically, the present invention relates to a method for producing an ester polyol, which uses an amine compound as a catalyst when producing an ester polyol by adding an alkylene oxide to a hydroxycarboxylic acid-containing acid.

[0002]

2. Description of the Related Art In the midst of global freon regulation, when producing rigid polyurethane foam using a blowing agent that replaces freon represented by cyclopentane, etc., the thermal conductivity required for rigid polyurethane foam with conventional polyether polyols. Since it is difficult to maintain physical properties such as rate and strength, in recent years, ester polyols as resin components have attracted attention.

The ester polyol is 300 to 800 mg KO in the same manner as the polyether polyol which is generally used as a resin component in the production of rigid urethane foam.
Not only is a hydroxyl number of H / g required, it is essential that approximately no unreacted carboxylic acid remains. For details, see Japanese Patent Application No. 5-16 filed previously.
No. 7698, the acid value in the ester polyol product when manufacturing a rigid polyurethane foam is 5 mgKOH / g.
The following are described, and lower ones are preferable. That is, when a large amount of unreacted carboxylic acid remains in the ester polyol, problems such as inhibiting the catalytic action of the urethanization catalyst during urethane production and reducing storage stability of the resin occur. .

Conventionally, as a method for producing an ester polyol, a polyhydric alcohol containing a hydroxycarboxylic acid or a polyhydric carboxylic acid obtained from a carboxylic acid cyclic anhydride and a polyhydric alcohol described in JP-A-3-86735. It is known that a dehydration condensation reaction with However, the method for producing an ester polyol by the dehydration condensation method requires high temperature and a long time, and is not necessarily industrially suitable.

On the other hand, when carrying out the addition reaction of carboxylic acid and alkylene oxide, it is a known fact that a catalyst is required. For example, literature (Surface 8-508 (1970), Engineering Journal 61-358, 61-1473, etc.). ), The catalytic performance of alkali metal hydroxides and lower amines has been studied in detail. However, these documents only show reaction examples of monocarboxylic acids and alkylene oxides, and their utility for the production of the ester polyol according to the present invention was unclear. Then, the present inventors have tried to synthesize an ester polyol for producing a rigid urethane foam using these catalysts, and as a result, various unfavorable problems have been clarified.

For example, the method using an alkali metal hydroxide typified by sodium hydroxide and potassium hydroxide is not preferable because a large excess of alkylene oxide is required to reduce the acid value. That is, Japanese Patent Application No. 5
As described in JP-A-167698, an ester polyol having an adduct of an excess of alkylene oxide as a composition reduces the dimensional stability and compressive strength of the foam, and is not preferred for producing a rigid polyurethane foam. Because it is.

[0007] Usually, when an alkali metal catalyst is removed from a product, an appropriate amount of acid and water are required.
It also causes hydrolysis of the ester group, making its purification extremely difficult. When a lower amine catalyst typified by triethylamine is used, problems such as deterioration in product hue, odor and other qualities and influence on reactivity during urethane production occur, which is not preferable as a product.

Further, Japanese Unexamined Patent Publication (Kokai) No. 1-98840 describes a useful amine catalyst as a synthetic catalyst for polyether polyols, which does not deteriorate the quality such as hue and odor and does not require purification and filtration steps. However, there is no description of addition of alkylene oxide to carboxylic acid. Further, when the reaction of the hydroxycarboxylic acid-containing acid and the alkylene oxide was carried out by the present inventors using a catalyst generally applicable, the decrease of the acid value was insufficient at a reaction temperature of 120 ° C or lower, and the reaction temperature was 120 ° C. In the above case, dehydration condensation at high temperature occurs simultaneously and the acid value decreases, but the hue of the product deteriorates and the viscosity increases, which is not suitable for producing a rigid polyurethane foam.

[0009]

SUMMARY OF THE INVENTION The object of the present invention is to solve the above-mentioned problems in the prior art in the production of ester polyols, and to produce ester polyols which give rigid polyurethane foam good physical properties. To do. That is, the minimum alkylene oxide is used to reduce the acid value, the reactivity during the production of polyurethane is not adversely affected, and the rigid polyurethane foam is provided with good physical properties, purification and filtration steps are not required, and the hue is The object of the present invention is to produce an ester polyol for rigid polyurethane, which is good in terms of quality such as odor.

[0010]

Means for Solving the Problems The inventors of the present invention have conducted extensive studies to find out a method for producing an ester polyol that solves the above-mentioned problems, and as a result, as a result, an alkylene oxide of alkylene oxide was used in a specific temperature range with a specific catalyst. The present invention has been completed by combining an addition reaction and a condensation reaction.

That is, the present invention is a method for producing an ester polyol by an addition reaction of a hydroxycarboxylic acid-containing acid obtained by a reaction of a carboxylic acid cyclic anhydride with a polyvalent active hydrogen compound and an alkylene oxide. Using an amine compound represented by the formula (I) (Formula 2),

Embedded image (In the formula (I), R1 represents an alkyl group or an alkenyl group having 8 to 18 carbon atoms, and R2 and R3 represent a hydrogen atom or an alkyl group having 1 to 8 carbon atoms.) 1 to 1 mol of a carboxyl group Using 2 moles of alkylene oxide, reaction temperature 80-120 ° C, followed by 120
A method for producing an ester polyol, which comprises reacting at 150 ° C.

The amine compound used as a catalyst in the present invention is dimethyloctylamine, trioctylamine, dimethyldecylamine, dimethyllaurylamine, dimethylstyrylamine, dimethylpalmethylamine, dimethyloleylamine, dimethylstearylamine, dimethyllinoleic. Amine, dimethyl linolenic amine and the like are used. The amount of the catalyst used is not particularly limited, but it is used in an amount of 0.01 to 5.0% by weight, preferably 0.1 to 1.0% by weight, based on the amount of product produced after the reaction.

Examples of the carboxylic acid cyclic anhydride used in the present invention include phthalic anhydride, pyromellitic dianhydride, succinic anhydride, glutaric anhydride, maleic anhydride and tetrachlorophthalic anhydride. These carboxylic acid cyclic anhydrides can be used alone or in combination of two or more, and the mixing ratio can be used in any range.

The polyvalent active hydrogen compound includes ethylene glycol, diethylene glycol, propylene glycol,
Dipropylene glycol, 1,2-butanediol,
Typical examples include diols such as 1,3-butanediol and 1,4-butanediol, triols such as glycerin, trimethylolethane and trimethylolpropane, tetrols such as pentaerythritol and diglycerin, and hexitols such as sorbitol. Aliphatic polyhydroxy compounds, or aromatic hydroxy compounds represented by glucose, lactose, maltose, sucrose, starch and other carbohydrates, bisphenol A, condensates of phenol and formaldehyde, ethanolamine, diethanolamine, triethanolamine, isopropanol Alkanolamines represented by amines, diisopropanolamine, triisopropanolamine and the like are also included. A compound obtained by adding an alkylene oxide to the polyvalent active hydrogen compound as shown above can also be used as the polyvalent active hydrogen compound. These polyvalent active hydrogen compounds can be used alone or in admixture of two or more, and the mixing ratio can be used in any range.

The hydroxycarboxylic acid-containing acid obtained by the reaction of a carboxylic acid cyclic anhydride and a polyvalent active hydrogen compound is not particularly limited in its production method, but is 0.5 to 2.0 with respect to 1 mol of the carboxylic acid cyclic anhydride. It is preferable to carry out a ring-opening addition reaction with a mole of a polyvalent active hydrogen compound. If it is 0.5 mol or less, the viscosity of the product will be high, and if it is 2.0 mol or more, the acid value will not be sufficiently lowered, and thus both are not preferable. Also,
The resulting hydroxycarboxylic acid-containing compound may be a mixture with a polyhydric active hydrogen compound and a hydroxyamide-containing compound obtained when at least one of ethanolamine and diethanolamine is used in an arbitrary mixing ratio. The alkylene oxide includes ethylene oxide, propylene oxide, butylene oxide, styrene oxide and the like,
Each can be used alone or in combination of two or more.

The method for producing an ester polyol of the present invention is as follows, in which a hydroxycarboxylic acid-containing acid and a predetermined amount of catalyst are charged, and 1 to 2 mol of alkylene oxide per 1 mol of carboxyl group is gradually added and reacted. If it is 1 mol or less, the acid value will not decrease, and if it is 2 mol or more, the physical properties such as dimensional stability and compression strength of the rigid polyurethane foam will be deteriorated, which is not preferable.

The reaction temperature is 80 to 120 ° C., and the addition reaction of the carboxyl group and the alkylene oxide is mainly carried out.
If the temperature is lower than 80 ° C, the reaction progresses extremely slowly and is not industrially suitable. On the other hand, at 120 ° C. or higher, the condensation reaction between the carboxylic acid and the hydroxyl group in the reaction system causes an excessive increase in the molecular weight, which increases the viscosity of the final product, which is not preferable. The pressure during the reaction is not particularly limited, but is preferably 10 kg / cm 2 or less. The reaction time is not particularly limited, but the decrease in the internal pressure of the reactor is 0.01 to 0.2 kg / cm 2/30 mi.
A reaction time of about n is preferable. Continue to 120
The temperature is raised to ˜150 ° C., and the condensation reaction between the residual carboxylic acid and the hydroxyl group existing in the reaction system and the addition reaction between water and alkylene oxide by-produced by the condensation reaction are mainly performed. At this time, if the temperature is 120 ° C. or lower, the condensation reaction is extremely slow and it takes a long time to reduce the acid value, which is not industrially suitable. Further, if it is 150 ° C. or higher, the viscosity is increased and the hue is deteriorated, which is not preferable. The acid value of the product is preferably 5 mgKOH / g or less, more preferably 1 mgKOH / g or less.

[0018]

EXAMPLES The present invention will be described more specifically below with reference to examples. The results of Examples, Comparative Examples and Reference Examples are
Shown in Tables 1-3.

[0019]

[Table 1]

[0020]

[Table 2]

[0021]

[Table 3]

Example 1 6.689 kg of phthalic anhydride, 2.034 kg of glycerin, 2.081 kg of 1,4-butanediol and 67.5 g of dimethylpalmitylamine in an internal volume of 30 l
Was charged into the reactor. 3kg after replacing the reactor with dry nitrogen
/ Pressure to 1 cm2 / G to raise the temperature, and after reacting at 100 ° C for 1 hour, make the inside of the reactor normal pressure and set to 100 ° C so that the internal pressure of the reactor is kept below 4.0 kg / cm2G. 4.194 kg of propylene oxide were added. After that, the internal pressure of the reactor dropped by 0.05 kg / cm2 / 30
It stirred for 5 hours until it became min, and heated up at 120 degreeC.
Then, the mixture was stirred for 5 hours until no decrease in internal pressure was observed. After completion of the reaction, the remaining propylene oxide was removed by reduced pressure, the internal temperature was cooled to 80 ° C., and the contents were taken out. The obtained product was 14.503 kg, which was a light yellow transparent liquid, had no acid value and had a hydroxyl value of 423.
The mgKOH / g and the viscosity were 25000 cps / 25 ° C.

Comparative Example 1 6.689 kg of phthalic anhydride, 2.034 kg of glycerin, 2.081 kg of di1,4-butanediol and 67.5 g of dimethylpalmitylamine in an internal volume of 30.
After charging to the reactor of 1 and carrying out hydroxycarboxylic acid-containing oxidation by the same operation as in Example 1, the temperature was set to 100 ° C. and 4.474 kg of propylene oxide was added. Then, the mixture was stirred for 10 hours until no decrease in the internal pressure of the reactor was observed, and after the reaction was completed, the remaining propylene oxide was removed by reduced pressure, the internal temperature was cooled to 80 ° C., and the contents were taken out. The obtained product was 14.763 kg, which was a light yellow transparent liquid and had an acid value of 7.2 mgKOH / g.
Hydroxyl number is 400mgKOH / g, viscosity is 250
It was 00 cps / 25 ° C.

Comparative Example 2 6.689 kg of phthalic anhydride, 2.034 kg of glycerin, 2.081 kg of 1,4-butanediol and 67.5 g of dimethylpalmitylamine were used in an internal volume of 30 l.
After carrying out the hydroxycarboxylic acid-containing oxidation by the same operation as in Example 1, the temperature was set to 130 ° C., and 4.474 kg of propylene oxide was added.
Then, the mixture was stirred for 6 hours until no decrease in internal pressure of the reactor was observed. After completion of the reaction, the remaining propylene oxide was removed by reduced pressure, the internal temperature was cooled to 80 ° C., and the contents were taken out. The obtained product was 14.895 kg, which was a dark brown liquid, had no acid value and had a hydroxyl value of 40.
The viscosity was 8 mgKOH / g and the viscosity was 75,000 cps / 25 ° C. In Comparative Example 1, the acid value remains, and in Comparative Example 2, the viscosity is increased due to the high molecular weight due to the condensation reaction. In Example 1, by carrying out the reaction in two steps of addition and condensation of alkylene oxide to carboxylic acid, it is possible to control acid value reduction and viscosity increase using a minimum amount of alkylene oxide. Effectiveness is recognized as the most suitable ester polyol production method for foam production.

COMPARATIVE EXAMPLE 3 6.689 kg of phthalic anhydride, 2.034 kg of glycerin, 2.081 kg of 1,4-butanediol and 45 g of potassium hydroxide were charged into a reactor having an internal volume of 30 l, and an example was obtained. By the same operation as in 1., 4.194 kg of propylene oxide was added. After that, the internal pressure of the reactor is 1
The mixture was stirred for 8 hours until it reached kg / cm 2. After the reaction,
The residual propylene oxide was removed by reduced pressure, the internal temperature was cooled to 80 ° C, and the product taken out was 14.298 kg.
It was a pale yellow transparent liquid. The acid value of this product is 81.7.
mg KOH / g, hydroxyl number is 326.6 m
It was gKOH / g. As can be seen from this Comparative Example 3,
With potassium hydroxide catalyst, the acid value is 81.7 mgKOH / g
The addition of alkylene oxide to carboxylic acid was insufficient.

Comparative Example 4 6.689 kg of phthalic anhydride, 2.034 kg of glycerin, 2.081 kg of 1.4-butanediol and 67.5 g of triethylamine were charged into a reactor having an internal volume of 30 liters, and 4. The same operation as in Example 1 was carried out using 194 kg of propylene oxide. The product is 14.37
It is a dark brown liquid at 5 kg with no acid value remaining, a hydroxyl value of 438 kg and a viscosity of 67,000 cps / 25.
° C.

Comparative Example 5 6.689 kg of phthalic anhydride, 2.034 kg of glycerin, 2.081 kg of 1.4-butanediol and 67.5 g of pentamethyldiethylenetriamine were charged into a reactor having an internal volume of 30 liters, The same operation as in Example 1 was carried out using 4.194 kg of propylene oxide.
The product weighs 14.789 kg and is a dark brown liquid with no residual acid value, hydroxyl value of 410 kg and viscosity of 520.
It was 00 cps / 25 ° C. In Comparative Examples 3 and 4, although the acid value of the product does not remain, it is a brown liquid and has a strong amine odor, which is extremely intolerable when actually used in the production of rigid polyurethane foam.
The results obtained in Example 1 and Comparative Example are shown in Table-1.

Examples 2 to 4 Ester polyols were produced in the same manner as in Example 1. However, as the catalyst, dimethyloctylamine, dimethyllaurylamine, and dimethyllinoleic amine were used.

Example 5 6.689 kg of phthalic anhydride, 2.034 kg of glycerin, 2.081 kg of 1,2-butanediol and 67.5 g of dimethylpalmitylamine in an internal volume of 30 l
The reactor was charged and the same operation as in Example 1 was performed using 4.194 kg of propylene oxide. The obtained product was 14.789 kg, which was a pale yellow transparent liquid, had no acid value remaining, had a hydroxyl value of 412 mgKOH / g and a viscosity of 35000 cps / 25 ° C.

Example 6 5.2226 kg phthalic anhydride, 6.497 kg ethanolamine propylene oxide adduct (hydroxyl number 975 mg KOH / g) and 67.5 g dimethylpalmitylamine are charged to a reactor having an internal volume of 30 l. And 4.
The same operation as in Example 1 was performed using 718 kg of propylene oxide. The obtained product was 14.289 kg, which was a pale yellow transparent liquid, had no acid value remaining, had a hydroxyl value of 431 mgKOH / g and a viscosity of 52000 cps /
It was 25 ° C.

Example 7 6.343 kg of phthalic anhydride, 1.929 kg of 1,
2-Butanediol, 2.250 kg of diethanolamine and 67.5 g of dimethylpalmitylamine were charged into a reactor having an internal volume of 30 l, and the same operation as in Example 1 was carried out using 4.478 kg of propylene oxide. The obtained product was 14.763 kg, which was a pale yellow transparent liquid, had no acid value and had a hydroxyl value of 420 mgKO.
The H / g and the viscosity were 45,000 cps / 25 ° C.

Example 8 5.179 kg of succinic anhydride, 2.385 kg of glycerin, 2.330 kg of 1,2-butanediol, and 67.5 g of dimethylpalmitylamine in an internal volume of 30.
It was charged in a reactor (1), and the same operation as in Example 1 was performed using 5.106 kg of propylene oxide. The product obtained was 14.892 kg, a light yellow transparent liquid,
No acid value remains, hydroxyl value is 484 mgKOH /
The viscosity was 12000 cps / 25 ° C.

Example 9 6.009 kg pyromellitic dianhydride, 4.190
Charge propylene glycol (kg) and dimethyl palmitylamine (67.5 g) into a reactor having an internal volume of 30 l,
The same operation as in Example 1 was carried out using 4.798 kg of propylene oxide. The product obtained is 14.578
It is a pale yellow transparent liquid in kg, has no acid value, has a hydroxyl value of 413 mgKOH / g and a viscosity of 65,000.
cps / 25 ° C.

Example 10 7.093 kg phthalic anhydride, 2.204 kg glycerin, 1.486 kg ethylene glycol and 6
7.5 g of dimethylpalmitylamine was charged to a reactor having an internal volume of 30 l. Replace the reactor with dry nitrogen to 3 kg /
After pressurizing to cm2G and raising the temperature and reacting at 100 ° C for 1 hour, the inside of the reactor was set to 2 kg / cm2G, the reaction temperature was set to 100 ° C, and the internal pressure of the reactor was 4.0 kg / cm2.
4.194 kg ethylene oxide was added over 5 hours to keep it below G. After that, the internal pressure of the reactor is 3 kg
The mixture was stirred for 1 hour until the temperature reached / cm @ 2, further heated to 120 DEG C., and reacted for 3 hours. After completion of the reaction, residual ethylene oxide was removed by reduced pressure, the internal temperature was cooled to 80 ° C., and the contents were taken out. The product obtained is 14.78.
It is a light yellow transparent liquid at 6 kg, has no acid value, has a hydroxyl value of 448 mgKOH / g and a viscosity of 1480.
It was 0 cps / 25 ° C.

Reference Example 1 and Comparative Reference Examples 1 and 2 A rigid polyurethane foam was prepared using the ester polyol obtained in Example 1 and a physical property test was conducted. Silicone foaming agent L-542 on 100 g of the above ester polyol
0 (product of Nippon Unicar) 1.0 g, Freon 11B (product of Mitsui DuPont Fluorochemicals) 17.5 g, tetramethylhexamethylenediamine 2.3 g, and pure water 0.5 g were added and mixed well to obtain a resin solution. After that, diphenylmethane diisocyanate (NCO content 30.8%) was added 1.05 times as much as the amount that reacts with the active hydrogen of the resin solution as standard, and stirred vigorously to measure 25 cm in length × 25 cm in width × 18 cm in height. It was poured into a cardboard box.

After measuring the rise time by the foaming (initiation time) and the time for the foam surface to lose its stickiness (tack free time), after aging at room temperature for 24 hours, the physical properties of the obtained rigid polyurethane foam were tested. The physical property test methods are as follows. (1) Specific gravity; according to ASTM D-1622 59T. (2) Compressive strength: According to ASTM D-1621 59T. (3) Dimensional stability: A 100 × 100 × 100 mm foam was allowed to stand under the conditions shown in Table 3, and the rate of change in the length after standing with respect to the length before standing was determined.

Physical properties of the foam are shown in Table 3. For comparison in Table 3, the acid value is 7.2 in the reaction at 100 ° C. in Comparative Example 1.
And the viscosity of 750 in the reaction of Comparative Example 2 at 130 ° C.
The foaming characteristics and foam physical properties using the one having a temperature of 00 cps / 25 ° C. are also shown. From Table 3, the foaming characteristics of the ester polyol produced by the method of the present invention were good.
In Comparative Example 1, the reactivity was low, and the isocyanate and the resin phase were separated during foaming. In Comparative Example 2, the mixing property was poor and the operation during mixing was difficult.

[0038]

According to the method of the present invention, in the production of ester polyol, the reaction is carried out in two steps of addition and condensation of alkylene oxide to carboxylic acid, thereby using a minimum amount of alkylene oxide to lower the acid value and increase the viscosity. In addition, it has the characteristics that the product can be controlled, the number of purification steps is small, and a product with stable quality can be obtained. Therefore, it is recognized as effective as a method for producing an ester polyol most suitable for producing a polyurethane foam. In addition, the product obtained by the present production method has excellent hue as a raw material for a rigid polyurethane foam and has a light hue and little offensive odor.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroshi Takayanagi 1190 Kasama-cho, Sakae-ku, Yokohama-shi, Kanagawa Mitsui Toatsu Chemical Co., Ltd.

Claims (1)

[Claims] 1. A method for producing an ester polyol by an addition reaction of a hydroxycarboxylic acid-containing acid obtained by reacting a carboxylic acid cyclic anhydride with a polyvalent active hydrogen compound, and a method of producing an ester polyol, wherein the following general formula (I) is used as a catalyst. Using the amine compound represented by (Chemical formula 1), (In the formula (I), R1 represents an alkyl group or an alkenyl group having 8 to 18 carbon atoms, and R2 and R3 represent a hydrogen atom or an alkyl group having 1 to 8 carbon atoms.) 1 to 1 mol of a carboxyl group Using 2 moles of alkylene oxide, reaction temperature 80-120 ° C, followed by 120
A method for producing an ester polyol, which comprises reacting at 150 ° C.