JPS61272230A - Production of polycarbonate - Google Patents

Abstract

PURPOSE:To obtain a polycarbonate, having a constant molecular weight and quality, and containing terminal hydroxyl groups and suitable for an intermediate, modifier or plasticizer, etc., for various polymers. CONSTITUTION:(B) A hydroxy compound, e.g. diethylene glycol, in an amount satisfying the formula [a is the hydroxyl number of the component (A); b is the hydroxyl number of the aimed polycarbonate; m is the molecular weight of the component (B); X is the weight of the component (A); Y is the weight of the component (B)] is added to (A) a polycarbonate having a high molecular weight, e.g. 500-50,000, and the resultant mixture is reacted, e.g. at 50-300 deg.C under reduced pressure for 2hr to afford the aimed polycarbonate with good reproducibility.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for producing a polycarbonate having a low molecular weight and having terminal hydroxyl groups.

/+ Prior Art] Polycarbonates having terminal hydroxyl groups, especially aliphatic polycarbonate geo-p, are useful as polymer intermediates, and when used as soft segments of elastomers, for example, they have excellent performance in energizing properties and hydrolysis resistance. Elastomers can be obtained.

Polycarbonates having terminal hydroxyl groups have conventionally been produced by the so-called phosgene method using a hydroxy compound and phosgene, and by the transesterification method using a hydroxy compound and a carbonate ester. Methods for producing polycarbonate using the phosgene method and the transesterification method are known, but it has been difficult to obtain polycarbonates with arbitrary molecular weights with good reproducibility. That is, conventionally, the molecular weight by the phosgene method was controlled by the molar ratio of the hydroxy compound and phosgene, but due to the hydrolysis reaction of phosgene, the molar ratio could not be precisely controlled and a polycarbonate with a constant molecular weight could not be obtained. In addition, the transesterification method usually involves heating the hydroxyl compound and ethyl carbonate in the presence of a catalyst, distilling off the by-produced hydroxyl compound under reduced pressure, and gradually increasing the reaction temperature and degree of vacuum to allow the reaction to proceed until the final temperature is reached. 200～
The reaction was completed at 250° C. and a reduced pressure of 1 to 5 tnHy. For this reason, it was difficult to strictly control the reaction time, reaction temperature, and degree of pressure reduction, and polycarbonate having a constant molecular weight could not be obtained, resulting in inconsistent quality. The molecular weight can also be controlled using a molecular weight regulator 4, such as a -valent hydroxy compound, but this method does not yield a polycarbonate containing terminal hydroxyl groups. Therefore, the present inventors conducted intensive studies on a method for producing polycarbonate of any molecular weight with good reproducibility, and finally established the method and completed the present invention.

[Structure and effects of the invention]

The present invention is a method for producing polycarbonate, which comprises reacting a high molecular weight polycarbonate with a droxy compound to produce a low molecular weight polycarbonate containing terminal hydroxyl groups.

More specifically, high molecular weight polycarbonate can be obtained by the phosgene method or the transesterification method.

The phosgene process involves introducing phosgene into a mixture of a hydroxy compound, a concentrated alkaline solution and a solvent, introducing phosgene and an alkaline solution simultaneously and through separate tubes into a solution or suspension of a hydroxy compound, or combining a hydroxy compound and phosgene. A high molecular weight polycarbonate can be obtained by either of the methods of reacting in an anhydrous solvent and then adding an alkaline solution. In the transesterification method, a hydroxy compound and a carbonate ester are reacted at a molar ratio of 1:10 to 10:1, preferably 1:3 to 3:1, using a catalyst if necessary. The reaction temperature is 100 to 300°C, preferably 150 to 250°C, and the by-produced hydroxy compound is heated to 0.1 to 300 mHy, preferably 1 to 150 r.
By distilling off with nxHy, a high molecular weight polycarbonate is obtained. The high molecular weight referred to here may be any value as long as it is larger than the molecular weight of the polycarbonate to be finally produced, but the molecular weight of polycarbonate is usually 50°.

~s　o　o　o　o are preferred.

Next, a hydroxy compound is added to the high molecular weight polycarbonate and reacted at a temperature of 50 to 300°C, preferably 150 to 250°C, under reduced pressure, normal pressure, or increased pressure to produce a polycarbonate of a desired molecular weight. The reaction is usually completed within 2 hours. For example, at a reaction temperature of 220°C, 30
Finish within minutes. The hydroxyl compound added here may be the same as that used in the production of the high molecular weight polycarbonate, or may be different.The amount to be added is determined by the following formula.

a: Hydroxyl value of high molecular weight polycarbonate b = Hydroxy value of polycarbonate to be finally produced m: Molecular weight of hydroxy compound to be added X: Weight of high molecular weight polycarbonate Y: Weight of hydroxy compound to be added However, in this formula, both ends are hydroxyl This is a case where a divalent hydroxy compound is added to a polycarbonate which is ``, and if it is more polyvalent, a similar formula can be derived accordingly.

Even if the molecular weight of polycarbonate containing terminal hydroxyl groups produced by the phosgene method or transesterification method according to the present invention is not reproducible as in the past, it is possible to obtain terminal hydroxyl groups of a desired molecular weight by adding a calculated amount of a hydroxy compound to the polycarbonate and reacting it. Have, po, capo awn? It has become possible to manufacture it with good reproducibility, and its quality has become constant.

Hydroxy compounds suitable for use in the present invention include diethylene glycol, triethylene glycol, polyethylene glycol, 1,3-propanediol, 2-methyl-1,3-, propanediol, 2,2-dimethyl-1,3 -Propanediol, 2-ethyl-1,3-propanediol, 1.4-butanediol, 1゜5-bentanediol, 1.6-hexanediol, 1.8-
Aliphatic diols such as octanediol, 2-ethyl-1,6-hexanediol, 2.2.4-trimethyl-1,6-hexanediol, 1,1o-decanediol, 1,12-dodecanediol, 1, 3-cyclohexanediol, 1,4-cyclohexanediol, cyclohexane-1,4-dimetatool, 212-bis(
4-hydroxychlorohequinyl)-pho/<n, 2,
Cycloaliphatic diols such as 2,4.4-tetramethylcycloptan-1,3-diol, aliphatic triols such as glycerin, trimethylolethane, and trimethylolpropane, pentaerynritol, cichentaerythritol, diglycerin, Aliphatic polyols such as sorbitol 4.4'-dihydroxydiphenol, 2.2-bis-(4-hydroxyphenyl)-propane% 2.2
-bis-(4--(2-hydroxyethoxy)phenyl)-propane, 2.4-bis-(4-hydroxypheny/Lz)-2-methylbutane, 1.1-bis-(4
-hydroxyphenyl)-cyclohexane, α,α-bis-(4-hydroxyphenyl)-propane, 2,2-
Pinu (3,4-dichloro-4-hydroxyphenyl)
-f loba, n, 2,2-pinu (3,5-dibromo-4
-Hydroxyphenyl)-propane and other aromatic hydroxy compounds alone or in mixtures.

Carbonic esters suitable for use in the transesterification reaction of the present invention include dimethyl carbonate, diethyl carbonate, digtyl carbonate, ethylene carbonate, trimethylene carbonate, tetramethylene carbonate,
1.2-propylene carbonate, 1,2-ethylene carbonate, 1.3-butylene carbonate, 2.3-
Ethylene carbonate, 1,2-pentylene carbonate, 1,3-pentylene carbonate, 1,4-pentylene carbonate, 2,3-bentylene carbonate,
Examples include 2,4-pentylene carbonate and diphenyl carbonate, with dimethyl carbonate, diethyl carbonate, digtyl carbonate, ethylene carbonate and diphenyl carbonate being particularly suitable.

In the transesterification reaction of the present invention, a catalyst may or may not be used. If used, any substance that promotes transesterification can be used, but particularly suitable are tetramethyl titanate, tetraethyl titanate, tetra n-globyl titanate, tetra iso-propyl titanate, tetraethyl titanate. titanium compounds such as, tin compounds such as diptyltin dilaurate, diptyltin oxide, digtyltin diacetate, organic acid salts such as magnesium, calcium, cerium, barium, zinc, etc., or combinations with the above titanium compounds. The amount of catalyst used is from 1 to 10,000 ppm, preferably from 10 to 1,000 ppm, based on the weight of the starting materials.
It is pm. .

The polycarbonate having terminal hydroxyl groups produced according to the present invention can be used for various purposes. For example, various resins such as vinyl chloride-vinyl acetate resin, natural rubber,
It can be used as a plasticizer for GRS rubber and its copolymer resins. It is also particularly useful as an intermediate and modifier for various polymers, and when used as a soft segment for elastomers such as polyurethane, polyester, and polyamide, elastomers with excellent heat resistance and hydrolysis resistance can be obtained. Furthermore, by modifying or adding or blending epoxy resins, acrylic resins, alkyd resins, unsaturated polyester resins, etc., it can be used to modify and improve the performance of various paints and thermosetting resin molded products.

〔Example〕

EXAMPLES Hereinafter, the present invention will be specifically explained with reference to Examples, but these are not intended to limit the present invention in any way. Note that parts and percentages in the following examples are based on weight. Further, the molecular weight in the examples was calculated using the following formula, and the hydroxyl value was measured according to JIS K1557.

Example 1 740 parts of honugen are introduced into a suspension of 590 parts of 1,6-hexanediol in methylene chloride at a temperature of 10 DEG to 15 DEG C. and with vigorous stirring. An aqueous solution of 600 parts of sodium hydroxide is then added dropwise, while the mixture is cooled and maintained at a temperature of 5-10°C. After adding 0.5 part of triethylamine, the temperature is raised to 30° C. and further heated to reflux. water 100
The organic layer was separated, washed with water, dried over sodium sulfate, and the solvent was distilled off under reduced pressure to obtain 690 parts of polycarbonate diol, which had a hydroxyl value of 39.5 (molecular weight: 2,840). To 200 parts of this polycarbonate diol, 17 parts of 1,6-hexanediol. T37+
.

0.2 parts, 1% hexane solution of tetrabutyl titanate
When 2 parts were added and the reaction was carried out at 200°C, the reaction was completed in 2 hours, and the resulting polycarbonate diol had a hydroxyl value of 112.2 and a molecular weight of 1. OOO was obtained.

Example 2 Hydroxyl value 39.5 obtained in Example 1 (molecular weight 2g40
) to 200 parts of polycarbonate diol, 8.07 parts of 1,6-hexanediol, and 1% of tetofugtyl titanate.
When 21 parts of hexane solution α was added and the reaction was carried out at 220° C. and normal pressure, the reaction was completed in 30 minutes, and the resulting polycarbonate diol had a hydroxyl value of 74.6 and a molecular weight of 1,504.

Example 3 Hydroxyl value obtained in Example 1: 39.5 (molecular weight: 2840)
2.50 parts of polycarbonate diol and 1.6-hexanedio-/l/465 parts of tetofuptyl titanate.
% hexane solution was added and the reaction was carried out at 220° C. and normal pressure, and the reaction was completed in 30 minutes.

The hydroxyl group of the produced polycarbonate diol is 56.0
A product with a molecular weight of 2004 was obtained.

Example 4 740 parts of ethylene carbonate, 709 parts of 6-hexanediol, and 5 parts of a 1% hexane solution of tetrabutyl titanate were placed in a reaction vessel and reacted at 200°C and normal pressure, and then the pressure was reduced to 80 to 100 ffHf to produce The resulting ethylene glycol was distilled off. After that, the reaction temperature was increased to 220°C.
The pressure was increased to 20-5 QmHp and the reaction was continued until the final 4
The pressure was reduced to mrHy to distill off the remaining ethylene glycol unreacted raw material. The obtained polycarbonate diol was 755 parts and had a hydroxyl value of 18.9 (molecular weight 5940).
Met. 1 for 120 parts of this polycarbonate diol
, 6-hexanedio-/l/13.37 parts and 2QO
When the reaction was carried out at ℃ and normal pressure, the reaction was completed in 5 hours.
The hydroxyl value of the produced polycarbonate diol is 112
．． A product with a molecular weight of 1000 was obtained.

Example 5 Hydroxyl value 18.9 (molecular weight 5940) obtained in Example 4
) 8.33 parts of 1,6-hexanediol was added to 200 parts of polycarbonate diol and reacted at 200°C and normal pressure. The reaction was completed in 2 hours, and the hydroxyl value of the polycarbonate diol produced was 56.0. A product with a molecular weight of 2004 was obtained.

Example 6 740 parts % of ethylene carbonate, 709 parts of 1.6-hexanediol, and 5 parts of a 1% hexane solution of tetrabutyl titanate were placed in a reaction vessel, reacted at 200°C and normal pressure, and then heated to 80 to 100 parts mHy. The pressure was reduced and the produced ethylene glycol was distilled off. Then 25-50mH
The reaction was continued by reducing the pressure to 5 ff HI, and finally the pressure was reduced to 5 ff HI to distill off residual ethylene glycol and unreacted raw materials. The obtained polycarbonate diol weighed 684 parts and had a hydroxyl value of 49.4 (molecular weight 2270). 1,6-hexanediol 5 to this polycarbonate diol
When 131 g was added and the reaction was carried out at 200° C. and normal pressure, the reaction was completed in 2 hours, and the resulting polycarbonate diol had a hydroxyl value of 112.2 and a molecular weight of 1000.

Example 7 400 parts of diphenyl carbonate, 237 parts of 1,6-hexanediol, and 13 parts of diptyltin oxide α0 were placed in a reaction vessel and reacted at 150°C and normal pressure.
The pressure was reduced to mHy and phenol was distilled off. then 10-5
Continue the reaction by reducing the pressure to 0flHg and finally lower the reaction temperature to 2.
The remaining phenol and unreacted raw materials were distilled off at a temperature of 00° C. and a reduced pressure of 3 mtH9. The obtained polycarbonate diol was 257 parts and had a hydroxyl value of 35.0 (molecular weight 32
10). This polycarbonate diol contains 1,
6-hexanediol 23,. Add 70 parts and 2゛20℃
When the reaction was carried out at normal pressure, the reaction was completed in 1 hour, and the hydroxyl value of the polycarbonate diol produced was 112.0.
A product with a molecular weight of 1002 was obtained.

Example 8.

428.4 parts of diphenyl carbonate, 243.8 parts of diethylene glycol, and 0.034 parts of digtyltin oxide were placed in a reaction vessel and reacted at 160°C and normal pressure.
The pressure was reduced to 11HH9 to distill off the phenol. After that 20
The reaction was continued by reducing the pressure to ~50 flHg, and finally the reaction temperature was 200°C and the degree of vacuum was 4tniH9 to distill off the remaining phenol and unreacted raw materials. The obtained polycarbonate diol was 256.8 parts and the hydroxyl value was 27.8.
(molecular weight 4040). Add 2293 parts of diethylene glycol to this polycarbonate diol,
At 00°C and normal pressure, a product with a reaction rate of 112 and a molecular weight of 1000 was obtained.

As can be seen from the above examples, according to the present invention, even if a polycarbonate having a terminal hydroxyl group with a desired molecular weight cannot be obtained by the phosgene method or transesterification method, the desired amount can be obtained by adding a calculated amount of a hydroxy compound to the polycarbonate and causing the reaction. It can be seen that products with a molecular weight of

Patent applicant Daicel Chemical Industries, Ltd. procedural amendment (
Spontaneous) 1985? June 1st, Director General of the Patent Office Mr. Michibe Uga 1. Display of the case, 1985 Patent Application No. 114576. 2. Name of the invention 3. Person making the amendment. Relationship with the case. Patent applicant postal code 590. 4. Subject of the amendment. Specification. Detailed description of the invention in column O (1
) In the fifth line from the top of page 3 of the specification, “Pressure degree 1” was corrected to “Pressure degree na 1” (2) In the fifth line from the fourth purchase of the specification, “Su, get” was changed to “Pressure degree 1”
(3) Page 7 of the specification, line 1 from the bottom, “Polyol 4,
41-” was corrected to “Polyol, 4,4'-J” (4)
7th line from the top of page 11 of the specification 1” JIS+KJ is replaced by “J
Corrected Is-Kl and added "The purpose of this example is to produce a polycarbonate diol with a molecular weight of 1,000" in the 10th line from the top of the same page.

(5) In the 11th line from the 12th line of the specification, "The purpose of this example is to produce a polycarbonate diol with a molecular weight of 1.500." was added, and in the 6th line from the bottom of the same page, "Department title" was added. ” was corrected to “bu, te” (6)
In the 1st line from the 13th purchase of the specification, it says, ``This example has a molecular weight of 2.
．． 000 polycarbonate diol. ” was added in the 5th line from the same purchase, “bu te” was changed to “bu, te”. In the 9th line from the same purchase, “kiwa” was changed to “base price wa”. In the 11th line from the top of the same page, “this implementation The example is aimed at producing a polycarbonate diol with a molecular weight of 1,000'.
Added ``Le unreacted'' in the first line from the bottom of the same page was corrected to ``Le, unreacted.'' In the third line from the bottom of the same page, ``The molecular weight of this example is i, oo.

(8) In the 5th line from the bottom of page 15 of the specification, ``The purpose of this example is to manufacture a polycarbonate diol with a molecular weight of 1.000'' was added. ” was added.

Claims (1)

[Claims] 1. A method for producing polycarbonate, which comprises reacting a high molecular weight polycarbonate with a hydroxy compound to produce a low molecular weight polycarbonate containing terminal hydroxyl groups. 2. The molecular weight of high molecular weight polycarbonate is 500 to 5.
0,000. 3. The molecular weight of low molecular weight polycarbonate is 200-2
0,000.