JP2658058B2 - Method for producing polycarbonate polyol - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial application field) The present invention has a terminal hydroxyl group which is excellent in heat resistance and hydrolysis resistance and is economically less colored and suitable for producing high-quality polyurethane. The present invention relates to a method for producing a polycarbonate polyol having the same.

(Prior art and its problems) Conventionally, carbonate compounds used for producing polycarbonate polyols include dimethyl carbonate, diethyl carbonate, di-n-butyl carbonate, ethylene carbonate, 1,2-propylene carbonate, diphenyl carbonate, and the like. . These carbonate compounds are usually produced by reacting phosgene with alcohol or phenol, but halogen compounds formed as a by-product of this phosgenation reaction, especially polycarbonates due to alkyl or aryl chloroformates remaining due to incomplete reaction. There is a problem that the polyol or the polyurethane is colored or other side reactions unfavorable for the production are caused, and the heterogeneous reaction hinders the production of a high-quality polycarbonate polyol or a polyurethane. However, in these production methods, if an alkali or alkaline earth metal or a metal compound thereof is used as a transesterification catalyst, the influence of halogen can be reduced. In order to accelerate the decomposition of the compound and cause an abnormal reaction with the isocyanate during the production of the polyurethane, post-treatment such as washing with water or neutralization is required.

Also, Japanese Patent Application Laid-Open No. 60-181125 discloses that coloring is reduced by adding an epoxy compound at the time of transesterification, but since a chlorine atom hardly comes out of the system, it is fundamental. Coloring is not improved, and the effect of improvement is small. Further, when the added amount of the epoxy compound is increased, there is a disadvantage that the epoxy compound reacts with the polyhydroxy compound to form an ether bond, thereby lowering the durability of the polyol.

(Problems to be Solved by the Invention) In order to solve these problems, the present inventors have conducted intensive studies, and as a result, have found a method for rapidly producing a high-quality polycarbonate polyol with little coloring, and Reached.

(Means for Solving the Problems) That is, the present invention relates to a method for producing a polycarbonate polyol by subjecting a dialkyl carbonate, a diaryl carbonate or an alkylene carbonate to a transesterification reaction with a polyhydroxy compound. An object of the present invention is to provide a method for producing a polycarbonate polyol, comprising using a dialkyl carbonate, a diaryl carbonate or an alkylene carbonate purified by a treatment.

(Constitution) As the dialkyl carbonate, diaryl carbonate or alkylene carbonate used in the present invention, dimethyl carbonate, diethyl carbonate, di-n-
Butyl carbonate, di-iso-butyl carbonate,
Diphenyl carbonate, ethylene carbonate, trimethylene carbonate, tetramethylene carbonate,
1,2-propylene carbonate, 1,2-butylene carbonate, 1,3-butylene carbonate, 2,3-butylene carbonate, 1,2-pentylene carbonate, 1,3-pentylene carbonate, 1,4-pentylene Carbonate, 1,5
-Pentylene carbonate, 1,5-pentylene carbonate, 2,3-pentylene carbonate and 2,4-pentylene carbonate.

The adsorbent used in the method of the present invention is an inorganic adsorbent, for example, activated clay, diatomaceous earth, acid clay, synthetic magnesium silicate, synthetic aluminum silicate, aluminum hydroxide, aluminum oxide, magnesium hydroxide, oxide Magnesium, magnesium hydroxide alumina, and activated carbon,
Examples include fluorite (zeolites, crystalline aluminosilicates), boraxite, A-type zeolites, faujasite, soda fluorite, mordenite, kihuite and the like. The average particle size of these adsorbents is widely used from several microns to several tens of mm and is not particularly limited. Preferably average pore size 20 to 100
Å, having a specific surface area of 10 to 600 m ² / g.

In the present invention, since the purpose is to adsorb trace halogen components in the raw material carbonate compound, for example, acid adsorbents such as acid clay, aluminum hydroxide, aluminum oxide, magnesium hydroxide, magnesium oxide, aluminum magnesium hydroxide, etc. Used effectively. These adsorbents can be used alone or as a mixture.
When the adsorbent is used by being added to the raw material carbonate compound, preferably, about 0.1 to 10% by weight of the adsorbent is added to the raw material carbonate compound.

As the polyhydroxy compound used in the method of the present invention, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 8-octanediol,
2-ethyl-1,6-hexanediol, 2-methyl-1,3
-Propanediol, neopentyl glycol, 1,3-
Cyclohexanediol, 1,4-cyclohexanediol, 2,2'-bis- (4-hydroxycyclohexyl)
-Propane, p-xylenediol, p-tetrachloroxylenediol, 1,4-dimethylolcyclohexane, bis-hydroxymethyltetrahydrofuran, di (2-hydroxyethyl) dimethylhydantoin, diethylene glycol, triethylene glycol, polyethylene glycol, dipropylene Glycol, polypropylene glycol, polytetramethylene glycol, thioglycol, trimethylolethane, trimethylolpropane, hexanetriol, pentaerythritol and the like. These polyhydroxy compounds can be used alone or as a mixture.

In the present invention, it is of course possible to carry out the reaction in a system in the absence of a catalyst, but usually, in order to smoothly proceed the esterification, an inorganic acid or an organic acid; Li, Na, K, Rb, Ca, M
g, Sr, Zn, Al, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Z
chlorides, oxides, hydroxides or salts of fatty acids such as acetic acid, oxalic acid, octylic acid, lauric acid, or naphthenic acid such as r, Pd, Sn, Sb or Pb; sodium methylate, sodium ethylate, Alcoholates such as aluminum triisopropoxide, isopropyl titanate, n-butyl titanate or octyl titanate; phenolates such as sodium phenolate; or other metals such as Al, Ti, Zn, Sn, Zr or Pb It is desirable to use all the catalysts used for ordinary esterification and transesterification, such as organometallic compounds. The amount of the catalyst used at that time is in the range of 0.000001 to 5% by weight based on the weight of the starting material, preferably 0.00001%.
It is in the range of 0.1%.

The method for purifying the dialkyl carbonate, diaryl carbonate or alkylene carbonate with the adsorbent in the present invention is not particularly limited, but usually the adsorbent is added to the raw material carbonate compound, and after adsorbing for a certain time,
For example, a method in which the raw material carbonate compound is passed through the adsorbent pre-coated with excess, or a method in which the raw material carbonate compound is passed through the cylinder filled with the adsorbent by applying pressure from above or below as necessary.

The use ratio of the dialkyl carbonate, diaryl carbonate, dialkylene carbonate and polyhydroxy compound of the present invention is not particularly limited, but in order for the terminal of the obtained polycarbonate polyol to be almost completely a hydroxyl group, it is necessary to use a dialkyl carbonate. Slightly stoichiometric excess to carbonate or diaryl carbonate, preferably 1-30%, more preferably 5-25%
Excess polyhydroxy compound is used.

The reaction conditions in the present invention are not particularly limited, but are usually
Perform transesterification at a low temperature of 180 ° C. or lower for about 1 to 4 hours, and further 150 to 280 ° C., preferably 180 to 240 ° C.
Reaction for about several hours, then finally at the same temperature 20mmHg
The reaction is carried out for several hours at the following pressure.

A feature of the present invention resides in that a raw material carbonate compound produced from phosgene is subjected to an adsorption treatment with an adsorbent, purified, and used to obtain a high-quality polycarbonate diol without coloring.

By reacting the hydroxyl-terminated polycarbonate polyol produced by the present invention with diisocyanate, it is possible to provide a polyurethane resin having extremely excellent wet resistance and hydrolysis resistance.

Next, examples of the present invention will be described, but the present invention is not limited thereto. “Parts” and “%” in the text are based on weight.

EXAMPLE 1 stirrer, ethyl alcohol and diethyl carbonate 1000 parts of aluminum hydroxide-magnesium produced by the reaction of phosgene glass reaction vessel equipped with a device thermometer _{(2.5MgO · Al 2 O 3 ·} xH 2 O ) 10 parts were charged, stirred at 100 ° C for 1 hour, and then passed through paper (10μ).

Next, 750 parts of the above-mentioned diethyl carbonate, 1,000 parts of 1,6-hexanediol and 1,000 parts of tetra-iso-propyl titanate were placed in a glass reaction vessel equipped with a stirrer, a thermometer, and a distillation tower.
Add 0.055 part, heat and distill off the ethyl alcohol generated by transesterification at 125 ° C.
Hold for hours. Further, the temperature was gradually raised to 180 ° C., kept at this temperature for 2 hours, and then raised to 200 ° C. and kept for 2 hours. Then gradually increase the degree of vacuum while maintaining the temperature at 200 ° C,
After reacting at a pressure of mHg for 2 hours, the temperature was raised to 220 ° C and 1,6-
A part of hexanediol was distilled off to obtain a polycarbonate polyol having a molecular weight of about 2,000. This polyol had a hydroxyl value of 54.2 and a melt color (APHA) at 75 ° C. of 60.

Example 2 In a glass reactor equipped with a stirrer and a thermometer, 1000 parts of ethylene carbonate produced by the reaction of ethylene glycol and phosgene and synthetic aluminum silicate 10
After stirring at 100 ° C. for 1 hour, the mixture was passed through paper (10 μ).

Next, a stirrer, a thermometer, a glass reaction vessel equipped with a distillation tower 704 parts of ethylene carbonate, 944 parts of 1,6-hexanediol and 0.4 parts of tetra-iso-propyl titanate.
055 parts were charged, heated under reduced pressure, and distilled at 150 ° C. while distilling ethylene glycol produced by the transesterification reaction.
For 8 hours. Further, the temperature was gradually raised to 180 ° C., kept at this temperature for 2 hours, and then raised to 200 ° C. and kept for 2 hours.
Thereafter, the degree of vacuum was gradually increased while maintaining the temperature at 200 ° C, and finally the reaction was performed at a pressure of 10 mmHg for 2 hours.
Distill a part of 1,6-hexanediol to obtain a molecular weight of about 2000
Was obtained. This polyol has a hydroxyl value of 55.9 and a melt color (APHA) at 75 ° C of 11
It was 0.

Example 3 1000 parts of diphenyl carbonate produced by the reaction of phenol and phosgene and 10 parts of activated clay were charged into a glass reaction vessel equipped with a stirrer and a thermometer, and stirred at 100 ° C. for 1 hour. ).

Next, 944 parts of the above diphenyl carbonate, 635 parts of 1,4-cyclohexanedimethanol and 0.055 part of tetra-iso-propyl titanate were charged into a glass reaction vessel equipped with a stirrer, a thermometer, and a distillation tower, heated and transesterified. 210 ° C while distilling off the phenol produced by the reaction
The temperature rose. After maintaining at this temperature for 10 hours while passing a small amount of nitrogen to help phenol distillation, 220
The temperature was raised to ° C. and kept for 2 hours. While maintaining the temperature, the degree of vacuum was gradually increased, and finally a part of 1,6-hexanediol was distilled off at a pressure of 10 mmHg to obtain a polycarbonate polyol having a molecular weight of 1,000. The hydroxyl value of this polyol is 11
At 5.0, the melt color at 75 ° C. (APHA) was 100.

[Comparative Example 1] In a glass reactor equipped with a stirrer, a thermometer and a distillation tower, diethyl carbonate 771 not purified by an adsorbent produced by the reaction of ethyl alcohol and phosgene was added.
, 991 parts of 1,6-hexanediol and 0.071 parts of tetra-iso-propyl titanate were charged, heated and maintained at 125 ° C. for 1 hour while distilling off ethyl alcohol produced by the transesterification reaction. Further, the temperature was gradually raised to 180 ° C., kept at this temperature for 2 hours, and then raised to 200 ° C. and kept for 2 hours. Thereafter, the degree of vacuum was gradually increased while maintaining the temperature at 200 ° C, and finally the reaction was performed at a pressure of 10 mmHg for 2 hours.
Then, a part of 1,6-hexanediol was distilled off to obtain a polycarbonate polyol having a molecular weight of about 2,000. This polyol had a hydroxyl value of 54.2 and a melt color (APHA) at 75 ° C. of 400.

Comparative Example 2 771 parts of diethyl carbonate produced by the reaction of ethyl alcohol and phosgene was placed in a glass reactor equipped with a stirrer, a thermometer and a distillation tower, and propylene oxide.
1.8 parts, 991 parts of 1,6-hexanediol and tetra-iso-
0.071 part of propyl titanate was charged, heated, and kept at 125 ° C. for 1 hour while distilling off ethyl alcohol produced by the transesterification reaction. Further, the temperature was gradually raised to 180 ° C., kept at this temperature for 2 hours, and then raised to 200 ° C.
Time kept. Thereafter, the degree of vacuum was gradually increased while maintaining the temperature at 200 ° C., and finally the reaction was performed at a pressure of 10 mmHg for 2 hours.
The temperature was raised to ° C to distill a part of 1,6-hexanediol to obtain a polycarbonate polyol having a molecular weight of about 1,000. This polyol had a hydroxyl value of 110.2 and a melt color (APHA) at 75 ° C. of 200.

Comparative Example 3 Diethyl carbonate produced by the reaction of ethyl alcohol and phosgene was purified by distillation at a boiling point of 126 to 127 ° C. under normal pressure in a glass reactor equipped with a packed column.

In a glass reaction vessel equipped with a stirrer, thermometer and distillation tower, 694 parts of the above-mentioned diethyl carbonate, 892 parts of 1,6-hexanediol and 0.064 of tetra-iso-propyl titanate were placed.
The mixture was heated at 125 ° C. for 1 hour while distilling out ethyl alcohol produced by the transesterification reaction. Further, the temperature was gradually raised to 180 ° C. and maintained at this temperature for 2 hours, and then raised to 200 ° C. and maintained for 2 hours. Then 200 ℃
After gradually increasing the degree of vacuum while maintaining the pressure, and finally reacting at a pressure of 10 mmHg for 2 hours, the temperature was raised to 220 ° C to distill a part of 1,6-hexanediol to obtain a polycarbonate polyol having a molecular weight of about 2,000. I got The hydroxyl value of this polyol is
At 55.1, the melt color at 75 ° C. (APHA) was 350.

Examples 1 to 3 and Comparative Examples 1 to 3 obtained as described above.
3 times each in a 500 ml glass bottle
Collect 100g at a time, cover with a little ventilation to 200 ℃
Was left in an oven for 5 days to compare the change in coloring.
The results are shown in Table 1.

Claims (1)

(57) [Claims] 1. A process for producing a polycarbonate polyol by subjecting a dialkyl carbonate, diaryl carbonate or alkylene carbonate to a transesterification reaction with a polyhydroxy compound, wherein the dialkyl carbonate, diaryl carbonate or alkylene is purified in advance by an adsorption treatment with an adsorbent. A method for producing a polycarbonate polyol, comprising using a carbonate.