JP3072530B2 - Method for producing polyester polyol - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a polyester polyol which is widely used for paints, adhesives, and other uses, and in particular, has little coloring and little decomposition by-products.

[0002]

2. Description of the Related Art Dehydration polymerization of a dibasic acid component composed of an aliphatic dibasic acid or an alicyclic dibasic acid or a mixture thereof with an aliphatic diol or a trifunctional or higher functional polyol or an alcohol component composed of a mixture thereof. Polyester polyols having terminal hydroxyl groups, which are condensation products, are used in large quantities as raw materials for urethane resins, melamine resins, and the like. As the aliphatic diol which is a raw material of these polyester polyols, ethylene glycol, propylene glycol, butanediol, neopentyl glycol, 1.6-hexanediol and the like are generally used. In particular, as an aliphatic diol, 2,2-diethyl-1,3-propanediol, 2-butyl-2-
Ethyl-1,3-propanediol and 2-pentyl-
It has been reported that urethane resins and melamine resins obtained from polyester polyols synthesized using 2-propyl-1,3-propanediol have various excellent physical properties. (See Japanese Patent Application Nos. 1-169123, 1-169124, 1-302644, 2-86668 and 2-86669)

[0003]

However, such 2,2-dialkyl-1,3-propanediols are in proportion to the number of carbon atoms of the alkyl group on the quaternary carbon at the 2-position.
It has been pointed out that it has a low binding energy to quaternary carbon and therefore often causes coloring under ordinary reaction conditions, and that it undergoes thermal decomposition to produce by-products such as aldehydes, carboxylic acids, and alcohols. The physical properties of the urethane resin and the melamine resin are reduced by the by-products of these coloring and thermal decomposition, and therefore, their use is restricted and the original use is impossible. Further, antimony trioxide, which is widely used as a catalyst for producing polyethylene glycol terephthalate (PET for short), becomes a heterogeneous reaction when reacted with an aliphatic or alicyclic carboxylic acid, and finally the catalyst is filtered. However, since the catalyst is essentially a transesterification catalyst, its activity is insufficient in a direct polycondensation reaction under atmospheric pressure, and there is a problem in practicality.

That is, an object of the present invention is to provide a polyester polyol using 2,2-dialkyl-1,3-propanediol as a diol component, which is free from coloring, has few by-products, and requires a catalyst removal step. There is no manufacturing method.

[0005]

The inventors of the present invention have conducted intensive studies on these problems, and as a result, when a titanium-based Lewis acid is used as a catalyst, a specific dibasic acid and a specific 2,2-dialkyl-1,3 are used. It has been found that a dehydration-condensation reaction with 1-propanediol easily proceeds, and a polyester polyol with little coloring and with extremely low generation of by-products can be obtained, thereby completing the present invention.

That is, the process for producing the polyester polyol of the present invention comprises the steps of: producing an aliphatic dibasic acid or an alicyclic dibasic acid or a mixture thereof with 2,2-dialkyl-1,2
3-propanediol (alkyl is selected from ethyl, propyl, butyl and pentyl, and the two alkyl groups may be the same or different) or the 2,2-dialkyl-1,3 containing a polyvalent hydroxy compound -
A titanium-based Lewis acid is added to propanediol as a catalyst in a range of 0.001% by weight or more and 0.025% by weight or less, and dehydration polycondensation is performed at a temperature of 200 ° C or more and 235 ° C or less.

The aliphatic dibasic acids used in the method for producing the polyester polyol of the present invention include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid and the like. Can be Examples of the alicyclic saturated dibasic acid include 1,2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, and 1,4-cyclohexanedicarboxylic acid.

[0008] 2,2-Dialkyl-1,3-propanediol includes 2,2-diethyl-1,3-propanediol, 2-butyl-2-ethyl-1,3-propanediol and 2-pentyl- 2-propyl-1,3-propanediol and the like.

Examples of the polyhydric hydroxy compound, that is, a trifunctional or higher polyol include trimethylolpropane, trimethylolethane, glycerin, pentaerythritol and the like.

The titanium-based Lewis acid used as a catalyst in the production method of the present invention includes tetraisopropyl titanate and tetrabutyl titanate. The amount of the catalyst used is 0.001 to 0.025 with respect to the total amount of the reaction components.
If it is 0.001% by weight or less, the reaction rate is low, and it is difficult to complete the reaction within a commercially practical time when obtaining a polyester polyol having a molecular weight exceeding 5,000. On the contrary, when the amount of the catalyst increases, the reaction rate increases. However, when the amount exceeds 0.025% by weight, the reaction rate does not change and the generation of by-products is accelerated, which is not preferable. When the reaction temperature is 200 ° C. or lower, the polycondensation reaction is slow and requires a long time, resulting in the generation of coloring and by-products. When the reaction temperature exceeds 235 ° C., the reaction time is shortened, Produces similar results.

[0011]

The present invention will be described more specifically below with reference to examples and comparative examples. The characteristic values of the synthesized polyester polyol were measured by an analytical method according to JIS-K0070 (Test method for acid value, saponification value, ester value, iodine value, hydroxyl value and unsaponifiable product of chemical products).

Example 1 In a 1-liter four-necked flask equipped with an oil-water separator equipped with a reflux condenser, a nitrogen inlet tube, a thermometer and a stirrer, 116.8 g of adipic acid, 2-butyl-2-ethyl- 173.3 g of 1,3-propanediol and 0.013 g of tetraisopropyl titanate as a catalyst were charged and reacted at a temperature of 220 ° C. for 6.5 hours. The water generated during this time was continuously taken out of the reaction system by an oil-water separator. After completion of the reaction, residual water and low boiling substances were removed at 120 ° C. for 1 hour under reduced pressure of 10 mmHg to obtain a polyester polyol. Its hue was colorless and transparent.

Example 2 131.4 g of adipic acid, 2-butyl-2-ethyl-
A target polyester polyol was obtained in the same manner as in Example 1 except that 169.2 g of 1,3-propanediol and 0.013 g of tetraisopropyl titanate as a catalyst were used, the temperature was 220 ° C., and the reaction time was 9.0 hours.
Its hue was colorless and transparent.

Example 3 146.0 g of adipic acid, 2-butyl-2-ethyl-
A target polyester polyol was obtained in the same manner as in Example 1, except that 178.7 g of 1,3-propanediol and 0.014 g of tetraisopropyl titanate as a catalyst were used at a temperature of 220 ° C. and a reaction time of 10.0 hours. Its hue was colorless and transparent.

Example 4 146.0 g of adipic acid, 2-butyl-2-ethyl-
173.7 g of 1,3-propanediol and 0.014 g of tetraisopropyl titanate as a catalyst, a temperature of 220 ° C. and a reaction time of 11.3 hours were obtained in the same manner as in Example 1 to obtain a target polyester polyol. Its hue was colorless and transparent.

Example 5 146.0 g of adipic acid, 2-butyl-2-ethyl-
A target polyester polyol was obtained in the same manner as in Example 1, except that 171.6 g of 1,3-propanediol and 0.014 g of tetraisopropyl titanate as a catalyst were used at a temperature of 220 ° C. and a reaction time of 12.5 hours. Its hue was colorless and transparent.

Example 6 146.0 g of adipic acid, 2,2-diethyl-1,3-
170.5 g of propanediol and 0.014 g of tetraisopropyl titanate as a catalyst at a temperature of 220
The target polyester polyol was obtained in the same manner as in Example 1 except that the reaction time was 13.0 ° C. and the reaction time was 13.0 hours. Its hue was colorless and transparent.

Example 7 156.7 g of adipic acid, 2,2-diethyl-1,3-
161.9 g of propanediol and 0.014 g of tetraisopropyl titanate as a catalyst at a temperature of 220
The desired polyester polyol was obtained in the same manner as in Example 1 except that the reaction time was 22.0 ° C. and the reaction time was 22.0 hours. Its hue was colorless and transparent.

Example 8 146.0 g of adipic acid, 218.4 g of 2-pentyl-2-propyl-1,3-propanediol and 0.016 g of tetraisopropyl titanate as a catalyst, at a temperature of 220 ° C. and a reaction time of 15.0 hours The desired polyester polyol was obtained in the same manner as in Example 1. Its hue was colorless and transparent.

Example 9 150.6 g of 1,4-cyclohexanedicarboxylic acid, 2
-Butyl-2-ethyl-1,3-propanediol 15
4.6 g and the desired polyester polyol were obtained in the same manner as in Example 1, except that 0.016 g of tetraisopropyl titanate was used as the catalyst, the temperature was 220 ° C., and the reaction time was 44.0 hours. Its hue was single yellow and transparent.

Example 10 146.0 g of adipic acid, 2-butyl-2-ethyl-
171.6 g of 1,3-propanediol and 0.014 g of tetraisopropyl titanate as a catalyst, a temperature of 205 ° C., and a reaction time of 16.5 hours were obtained in the same manner as in Example 1 to obtain a target polyester polyol.
Its hue was colorless and transparent.

Example 11 146.0 g of adipic acid, 2-butyl-2-ethyl-
171.6 g of 1,3-propanediol and 0.014 g of tetrabutyl titanate as a catalyst, temperature 205
The desired polyester polyol was obtained in the same manner as in Example 1 except that the reaction time was 16.5 ° C. and the reaction time was 16.5 hours. Its hue was colorless and transparent.

Example 12 146.0 g of adipic acid, 2-butyl-2-ethyl-
The same procedure as in Example 1 was repeated except for using 170.4 g of 1,3-propanediol, 8.75 g of trimethylolpropane, 0.028 g of tetraisopropyl titanate as a catalyst, a temperature of 215 ° C., and a reaction time of 24.0 hours. A polyester polyol was obtained. Its hue was colorless and transparent.

Comparative Example 1 146.0 g of adipic acid, 2-butyl-2-ethyl-
173.7 g of 1,3-propanediol and 0.12 g of antimony trioxide as a catalyst, 0.137 g of calcium acetate monohydrate, a temperature of 235 ° C. to 238 ° C., and a reaction time of 7.0 hours were the same as those in Example 1. The reaction was performed in the manner described. After the completion of the reaction, the reaction product was grayish brown and cloudy. The catalyst was removed by several pressure filtration operations.

Comparative Example 2 146.0 g of adipic acid, 2-butyl-2-ethyl-
173.7 g of 1,3-propanediol and 0.14 g of tetraisopropoxytitanate as catalyst, temperature 2
The reaction was carried out in the same manner as in Example 1, except that the reaction time was 25 ° C. and the reaction time was 15.0 hours. After the completion of the reaction, the reaction product was yellow.

Comparative Example 3 146.0 g of adipic acid, 2-butyl-2-ethyl-
The reaction was carried out in the same manner as in Example 1, except that 173.7 g of 1,3-propanediol, 0.014 g of tetraisopropoxytitanate as a catalyst, a temperature of 245 ° C., and a reaction time of 20.0 hours were used. After the completion of the reaction, the reaction product was orange-yellow.

Comparative Example 4 146.0 g of adipic acid, 2-butyl-2-ethyl-
In the same manner as in Example 1 except that 173.7 g of 1,3-propanediol and 0.028 g of FASCAT-4100 (a tin-based catalyst manufactured by M & T Chemicals, USA) as a catalyst, a temperature of 235 ° C., and a reaction time of 10.5 hours were used. The reaction was performed. After the completion of the reaction, the reaction product was yellow.

Tables 1, 2 and 3 show the characteristic values of various polyester polyols synthesized in the following Examples and Comparative Examples. The decomposition product is a value obtained by quantifying the total amount of low-boiling substances other than the raw materials by gas chromatography. The abbreviations of the reaction components in Tables 1, 2 and 3 are as follows. Diol component DMH: 2-butyl-2-ethyl-1,3-propanediol DMP: 2,2-diethyl-1,3-propanediol DMN: 2-pentyl-2-propyl-1,3-propanediol Polyol component TMP : Trimethylolpropane dibasic acid component AA: adipic acid CHDA: 1,4-cyclohexanedicarboxylic acid catalyst TPT: tetraisopropyl titanate TBT: tetrabutyl titanate Sb ₂ O ₃ : mixed catalyst of antimony trioxide and calcium acetate monohydrate FASCAT: FASCAT-4100

[0029]

[Table 1]

[Table 2]

[Table 3]

[0030]

According to the process for producing a polyester polyol of the present invention, 2,2-dialkyl-1,3 is used as a diol component.
-It is a production method which solves problems such as coloring and generation of by-products, which have been problems in the production of polyester polyols using propanediol. That is,
This is a very practical production method that has no coloring, produces very few by-products, and does not require a catalyst removal operation because the reaction system is homogeneous.

────────────────────────────────────────────────── (56) References US Patent 4,845,266 (US, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08G 18/42 C08G 63/85

Claims (1)

(57) [Claims] An aliphatic dibasic acid or an alicyclic dibasic acid or a mixture thereof and 2,2-dialkyl-1,3
-Propanediol (alkyl is selected from ethyl, propyl, butyl, pentyl, and the two alkyl groups may be the same or different) or the 2,2-dialkyl-1,3- Polyester polyol characterized by adding a titanium-based Lewis acid as a catalyst in a range of 0.001% by weight or more and 0.025% by weight or less to propanediol and performing dehydration polycondensation at a temperature of 200 ° C or more and 235 ° C or less. Manufacturing method.