JPH04209629A - Production of polyoxyalkylene polyol - Google Patents

Abstract

PURPOSE:To obtain the title polyol having a low degree of unsaturation and a high molecular weight by using a specified mercaptan compound in obtaining the title polyol by addition-polymerizing a polyfunctional active hydrogen compound with a specified alkylene oxide. CONSTITUTION:A process for producing the title polyol by addition-polymerizing a polyfunctional active hydrogen compound (e.g. a diol prepared by addition- polymerizing dipropylene glycol with propylene oxide) with a 2C or higher alkylene oxide (e.g. propylene oxide) containing propylene oxide in the presence of a catalyst (e.g. KOH), wherein a mercaptan compound (e.g. 2-mercaptoethanol) having at least two active hydrogen groups selected from SH and OH groups at least one of which is an SH group is used.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to a method for producing polyoxyalkylene polyol, and more specifically, a polyoxyalkylene monool with a low content of polyoxyalkylene monool having terminal unsaturated bonds, which is a by-product. ,
That is, the present invention relates to a method for producing a high molecular weight polyoxyalkylene polyol with a low degree of unsaturation.

Polyoxyalkylene polyols are essential as raw materials for manufacturing polyurethane resins and other products.

It is applied in a wide range of fields including foam, elastomers, reflective injection molding, paints, and adhesives.

[Conventional technology]

BACKGROUND ART Conventionally, a method is known in which a high molecular weight polyoxyalkylene polyol is produced by addition-polymerizing an alkylene oxide to a compound having an active hydrogen group such as a hydroxy group or an amine group in the presence of a catalyst.

For example, Japanese Patent Publication No. 45-149 describes alkylene oxides such as propylene oxide, ethylene oxide and butylene oxide, aliphatic alcohols, alkyl-substituted phenols, naphthols, polyalkylene glycols, polyhydric alcohols, organic amines and alkyl A method is described in which a low molecular weight compound having two or more active hydrogen groups, such as a mercaptan, is added by an anionic polymerization method using an alkali metal hydroxide such as potassium hydroxide as a catalyst.

The method of producing high molecular weight polyoxyalkylene polyols by anionic polymerization using an alkali metal hydroxide as a catalyst as described above is still the most commonly used method at present.

Journal of American Chemical Society 4
(Journal of American Che
mical 5ociety) vol, 81.337
4 pages (195!3), Journal of PolymerSc
ience) vol, 44.303 pages (1880),
and “Industrial Chemistry Magazine J! 1489 @ No. 3 501~
On page 505 (1966), in the production of polyether for urethane foam and nonionic surfactant,
When producing a high molecular weight polyoxyalkylene polyol by addition polymerizing propylene oxide using an alkali hydroxide as a catalyst, a portion of the raw material propylene oxide is isomerized to allyl alcohol, and then propylene oxide is addition polymerized to this. Furthermore, it has been reported that a polyoxypropylene monool having an allyl group or a propenyl group at the end is produced by transferring -S of the allyl group in the monol thus produced to a propenyl group.

Since such by-product monools have only one hydroxyl group in their molecular chains, they do not become polymers even when reacted with polyisocyanate, and polyurethane resins obtained by using polyols containing this monool It is known that the quality deteriorates in terms of physical properties and molding. Therefore, high molecular weight polyoxyalkylene polyols have a content of allyl groups and propenyl groups (specifically, JIS K-1
The degree of unsaturation specified in 557, the lower the unsaturation equivalent per Ig of polyoxyalkylene polyol (■eq/g), the better.

Furthermore, in Japanese Patent Application Laid-Open No. 11i3-277236, Zn3
[Go(ON) 612・Znc:I A catalyst is synthesized by reacting a double metal cyanide, typified by the 2 system, with a metal compound such as zinc chloride in the presence of a filter aid, and this catalyst is used to synthesize a catalyst. A method for polymerizing propylene oxide is described. According to this method, a polyoxyalkylene polyol with a low degree of unsaturation can be obtained, but there is a problem that the raw material for the catalyst is very expensive.

Additionally, JP-A-2-115211 describes a method for producing polyurethane foam by reacting a polyoxyalkylene polyol and a polyisocyanate compound in the presence of a blowing agent, a foam stabilizer, a catalyst, and other auxiliary agents. As oxyalkylene polyol, hydroxyl value 34-60,
A method using a material having an unsaturation degree Q of 0.3 rieq/g or less is described. This publication describes that the physical properties of polyurethane 2 ohms are improved by using a polyoxyalkylene polyol with a low degree of unsaturation, but the publication does not describe the method for producing polyoxyalkylene polyols with a low degree of unsaturation. Not listed.

[Problem to be solved by the invention]

Therefore, an object of the present invention is to provide a method for producing a high molecular weight polyoxyalkylene polyol with a low content of by-product polyoxyalkylene monool having an unsaturated bond at the terminal, that is, a low degree of unsaturation. That's true.

[Means to solve the problem]

As a result of intensive research to achieve the above object, the present inventors have discovered that active hydrogen compounds, catalysts, etc. can be used to produce high molecular weight polyoxyalkylene polyols by polymerizing alkylene oxides, mainly propylene oxide. It has been discovered that a polyoxyalkylene polyol with a reduced degree of unsaturation can be obtained by the presence of a specific mercaptan compound in addition to alkylene oxide, and the present invention has been achieved based on this discovery.

That is, the method for producing a polyoxyalkylene polyol of the present invention involves adding and polymerizing an alkylene oxide having two or more carbon atoms, including propylene oxide, to a polyvalent active hydrogen compound using a catalyst to synthesize a polyoxyalkylene polyol. The present invention is characterized in that a mercaptan compound containing two or more active hydrogen groups selected from mercapto groups and hydroxy groups and at least one of which is a mercapto group is present, in which a high molecular weight polyoxy The term alkylene polyol means one having a molecular weight of about 1000.

In the present invention, examples of polyvalent active hydrogen compounds as raw materials include ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol,
Phenol resin obtained by condensation of glycerin, diglycerin, pentaerythritol, nrubitol, sugar, bisphenol A, bisphenol At-JL- and formalin, ethylenediamine, piperazine, aniline, methylenebisaniline, 2,4-diaminotoluene, 2.6 -Diaminotoluene, thioglycol and the like.

In general, the polyhydric active hydrogen compounds mentioned above also include relatively high molecular weight polyols such as polyalkylene polyethers obtained from cyclic ethers such as tetrahydrofuran, or polyester diols obtained by ring-opening polymerization of cyclic lactones.

In addition, in the present invention, when producing a high molecular weight polyoxyalkylene polyol, 1/3 of the final target molecular weight is
A polyoxyalkylene polyol of ~115 is produced in advance in the first stage reaction tank, and this is used as an initiator to further produce a high molecular weight polyoxyalkylene polyol of 3,000 to 7,000 molecules in the second stage reaction tank. be able to. By using this method, it is possible to avoid the problem that when attempting to directly produce a high molecular weight polyoxyalkylene polyol from low molecular weight raw materials, stirring is impossible due to the small amount of raw materials at the initial reaction stage.

The catalyst used in the present invention is primarily an alkali hydroxide. - When propylene oxide is polymerized using alkali hydroxide as a catalyst during boat fishing, propylene oxide undergoes an isomerization reaction and allyl alcohol is produced as a by-product, and propylene oxide is addition-polymerized to this allyl alcohol, resulting in unsaturated terminals. A feature of the present invention is to generate a monool having a bond (allyl group and a propenyl group formed by rearrangement of the allyl group).The feature of the present invention is to add a mercaptan compound to the by-product having an unsaturated bond at the terminal to form a monool. The goal is to convert the into diols. Therefore, the catalyst used in the present invention is a catalyst that produces a monool having an unsaturated bond at the terminal as a by-product, and unless its catalytic performance is deactivated by the coexisting mercaptan compound, it is not a catalyst other than an alkali hydroxide. It can also be used.

As the alkylene oxide used in the present invention, propylene oxide, which tends to produce monools having unsaturated bonds as a by-product, is mainly used. But besides propylene oxide.

Ethylene oxide, butylene oxide, and other alkylene oxides, which are often used in combination with propylene oxide, can also be used.

Specifically, when producing a polyoxyalkylene polyol, propylene oxide may be first addition-polymerized, and then ethylene oxide may be addition-polymerized.
Furthermore, ethylene oxide and/or butylene oxide may be added before or after propylene oxide, or ethylene oxide or butylene oxide may be added after nifrohylene oxide, and then propylene oxide may be added. Other alkylene oxides may be added.

The mercaptan compound used in the present invention is a compound having two or more active hydrogen groups selected from a mercapto group and a hydroxy group, at least one of which is a mercapto group, and specifically, for example, 2-mercaptoethanol, 3-mercaptopropertool, 4-
Mercaptobutanol, monothioglycerol, dithioglycerol, 2,3-dimercapto-1-propatol, ethylene glycol-monomercaptoacetate,
Ethylene glycol mono(β-mercaptopropionate), diethylene glycol mono(β-mercaptopropionate), trimethylolpropane mono(β-mercaptopropionate)
-mercaptopropionate), neopentyl glycol-mono(β-mercaptopropionate), 1.4-
Examples include phthanesithiol, 1,8-cymercapto-3,6-sioxaoctane, and cy(2-mercaptoethyl) ether, and one or more of these can be selected and used.

Among them, 2-mercaptoethanol and 3-mercaptoethanol are particularly preferred.
Mercaptopropertool, 4-mercaptophthanol,
These are monothiocrycerol, ethylene glycol monomercaptoacetate, ethylene glycol mono(β-mercaptopropionate), and diethylene glycol mono(β-mercaptopropionate).

In the present invention, the raw material composition ratio when producing the polyoxyalkylene polyol is mercaptan equivalent to 1 mole to 5 times the mole of unsaturated bonds produced by the usual method of polymerizing alkylene oxide without feeding mercaptan. Add. More preferably, it is 1 to 3 times the mole.

There are two ways to add mercaptan: one is to add the alkylene oxide in advance, and the other is to add it continuously during the polymerization.

The polyoxyalkylene polyol obtained by the above method becomes a raw material for producing polyurethane resin. The method for producing the polyurethane resin is not particularly limited, and may be a known method.

〔Example〕

Specific examples of the present invention will be described below, but the embodiments of the present invention are not limited thereto.

[Compound used] 2-Mercaptoethanol A product of Toyo Kasei ■ was used. Boiling point 157.1”C/7
42m layer Hg, purity 88 by gas chromatography
% or more, viscosity 3.43 cp/25°C.

MDO 1,8-dimercapto-3,6-thioxaoctane, product rDMDOJ of Nisso Maruzen Chemical Co., Ltd., boiling point 225°C
, purity 99.7%.

Dial-1000 rDiol-1000J manufactured by Mitsui Toatsu Chemical Co., Ltd.
A diol with a molecular weight of approximately 1000 obtained by addition polymerizing propylene oxide to dipropylene glycol.

[Analytical Measurement Method] Measurement of degree of unsaturation (vinyl content) The method described in Section 6.7 "Total degree of unsaturation" in 1557R polyether test method for polyurethane j of the Japanese Industrial Standards (JIS) was followed.

Item 6.4 “Hydroxyl value” in “K 1557 r Polyether Test Method for Polyurethane” of Japanese Industrial Standards (JIS)
I followed the method.

Method for Measuring Mercaptan Concentration The copper flukylphthalate method, which is one of the methods for quantifying mercaptan, described in "Method for Confirming Trace Amounts of Organic Compounds" (Baifukan, 1957) was used. 0.1-0.3g of mercaptan
Weigh the sample containing the sample and make a 50% solution of butanol in a 125-ohm Erlenmeyer flask.

Add the 0.IN copper phthalate standard solution little by little, and the end point is the point at which the blue-green color of the titrant remains without disappearing. Perform a blank test and subtract this value from the above titration value to determine the mercaptan concentration.

Example 1 423g of D i OI-1000 and 4.76g
40 g of water in which potassium hydroxide was dissolved was charged into a 1-liter round-bottomed flask, and dehydrated at 105° C. and 8 to IQ mmHg for 4 hours. After transferring this to a 2-liter autoclave and adding 9.05 g of 2-mercaptoethanol.

After raising the temperature to 115°C, propylene oxide was continuously charged and the polymerization reaction was carried out at 5 atm for 3.5 hours. After stopping the charging of propylene oxide, the reaction was carried out for another 4 hours, and after one reaction was completed, the weight of the produced polyoxyalkylene diol was measured and found to be 1585 g. After removing residual propylene oxide under reduced pressure for 1 hour at 0.10-15 mHg, 10.3 g of 85% phosphoric acid and 80 g of water were added and a neutralization reaction was carried out at 100°C for 40 minutes. After adding a filter aid, the mixture was dehydrated at 100° C. and 10 to 201 mHg for 2 hours, and filtered to purify the polyoxyalkylene diol.

The analytical values of the product were as follows. The degree of unsaturation was clearly lower (better) than Comparative Example 1 shown below.

Comparative Example 1 When the same polymerization as in Example 1 was carried out without adding 2-mercaptoethanol, the following results were obtained.

The degree of unsaturation was clearly higher than in Example 1 and was 1 (poor).

Example 2 423 g of Dio
Dehydrated for hours.

Transfer this to a 2 liter autoclave, 8.70g
After adding DMDO, the temperature was raised to 115°C, propylene oxide was charged, and the polymerization reaction was carried out at 5 atm.
Time went. After stopping the charging of propylene oxide, the reaction was continued for another 4 hours, and after one reaction was completed, the weight of the produced polyoxyalkylene diol was measured and found to be 1595 g. This is further heated to 100℃, 10~
After removing the residual propylene oxide under reduced pressure at 15% Hg for 1 hour, add 10.3 g of 85% phosphoric acid and 80 g of water, perform a neutralization reaction at 100°C for 40 minutes, and then remove the filter aid. 100°C, 10-1
The polyoxyalkylene diol was purified by dehydration at 5+*mHg for 2 hours and filtration.The analytical values of the product were as follows. The degree of unsaturation was clearly lower than that of Comparative Example 1 and was rated as X (good).

Example 3 425g of Dial-1000 and 4.8
Pour 40 g of water in which 0 g of potassium hydroxide was dissolved into a 1 liter round bottom flask, and heat at 105°C, 8 to IO mmHg.
Dehydrated for 4 hours. This was transferred to a 2-liter autoclave, heated to 15°C, propylene oxide mixed with 2-mercaptoethanol was continuously charged, and a polymerization reaction was carried out at 5 atm for 3.5 hours. After stopping the charging of propylene oxide, the reaction was carried out for another 4 hours, and after the reaction was completed, the weight of the polyoxyalkylene diol produced was measured and found to be 1585 g. The total amount of 2-mercaptoethanol added to the polymerization reaction system was 9.28. Add this to 10 more
After removing residual propylene oxide under reduced pressure at 0°C and 10 to 15++ nHg for 1 hour, 10.4 g of 85
% phosphoric acid and 80 g of water were added to carry out a neutralization reaction at 100°C for 40 minutes, and after adding a filter aid, the mixture was heated at 100°C for 1 hour.
The polyoxyalkylene diol was purified by dehydration at 0-15 mmHg for 2 hours and filtration. The analytical values of the product were as follows. The degree of unsaturation was clearly lower (better) than Comparative Example 1 shown below.

〔Effect of the invention〕

According to the present invention, the content of polyoxyalkylene monool having terminal unsaturated bonds, which is a by-product, is low.
That is, it is possible to provide a method for producing a high molecular weight polyoxyalkylene polyol with a low degree of unsaturation.

Patent applicant Mitsui Toatsu Chemical Co., Ltd.

Claims (1)

[Claims] When synthesizing a polyoxyalkylene polyol by addition polymerizing an alkylene oxide having 2 or more carbon atoms, including propylene oxide, to a polyhydric active hydrogen compound using a catalyst, an active hydrogen group selected from a mercapto group and a hydroxy group is added. A method for producing a polyoxylalkylene polyol, which comprises coexisting a mercaptan compound having two or more mercaptan compounds, at least one of which is a mercapto group.