JP2534053B2 - Method for producing lactone polymer - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing a lactone polymer, and more particularly to a method for producing a monodisperse lactone polymer having almost no molecular weight distribution.

(Prior Art) A lactone polymer having a molecular weight of 500 to 5000 is particularly useful as a raw material for polyurethane resins, polyester resins, artificial leather, coating materials and the like.

The lactone polymer is, for example, ε-caprolactone, δ-
It is obtained by ring-opening polymerization of lactones such as valerolactone, but conventionally, an anionic ring-opening polymerization catalyst such as tetrabutyl titanate is used, and the reaction is performed at a high temperature of 100 ° C to 200 ° C. Therefore, not only the molecular weight distribution is wide due to side reactions such as transesterification, but also {weight average molecular weight / number average molecular weight (hereinafter abbreviated as w / n) = 2.5.
.About.3.5}, and a low polymer was also contained in a large amount.

(Problems to be Solved by the Invention) Lactone polymers having a wide molecular weight distribution have many practical problems in terms of physical properties of various resins, high viscosity, molding processability, handling, etc. Was desired. Regarding the improvement of the molecular weight distribution of the lactone polymer, the method disclosed in JP-A-57-155230 has recently been proposed. As shown in the examples, w / n = 1.
It is a lactone polymer with a considerable distribution of 5 to 1.8 and is not satisfactory.

(Means for Solving the Problems) In view of the above circumstances, the present inventors have studied a method for improving the molecular weight distribution of a lactone polymer, and as a result, w / n = 1.0
The inventors have found a method for obtaining a monodispersed lactone polymer having almost no molecular weight distribution of 1.2, and arrived at the present invention.

That is, this is a method of ring-opening polymerization of a lactone at a temperature of 100 ° C. or lower using an inorganic acid catalyst in the presence of one or more active hydrogen atom-containing compounds.

A method for reacting a lactone having 6 or more carbon atoms with an organic compound having an amino group or a hydroxyl group in the presence of an inorganic acid catalyst is described in JP-B-35-497, but the reaction temperature is 60 ° C or higher is preferable because of time. However, the present inventors have examined industrially important molecular weight distribution, and the distribution tends to widen as the reaction temperature increases, and the distribution rapidly widens at a temperature of about 100 ° C. or higher. On the contrary, it was found that a monodisperse lactone polymer having almost no distribution was obtained at a reaction temperature of 60 ° C or lower. An ideal polymer can be obtained at a lower temperature from the tendency of the reaction temperature and the molecular weight distribution, but from an industrial viewpoint, the lower limit is about -20 ° C, and therefore the preferable temperature range is -20 ° C to 60 ° C.
° C.

In the present invention, lactone is a general formula, (Wherein R represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and n represents an integer of 4 to 5), and specific examples include δ-valerolactone and ε. -Caprolactone and alkyl-substituted products of these.

The active hydrogen atom-containing compound is a compound containing a hydroxyl group, an amino group and a mercapto group. Examples of the compound containing a hydroxyl group include methanol, ethanol, propanol, n-butanol, 2-, 3-butanol, allyl alcohol, aliphatic alcohols such as 2-hydroxyethyl methacrylate, benzyl alcohol and phenylmethylcarbinol. Aromatic alcohols, cycloaliphatic alcohols such as cyclohexanol and trimethylhexanol, ethylene glycol, propylene glycol, 1,4
-Butanediol, polyethylene glycol, polypropylene glycol, polyoxytetramethylene glycol, and polyols such as glycerin, trimethylolpropane, cyclohexanediol, xylylene glycol, and other various phenols, organic carboxylic acids, compounds containing amino groups Examples of are primary aliphatic amines such as methyl-, ethyl-, n-propyl-, isopropyl-, n-butyl-, tert- and tert-butyl and their corresponding dialkylamines. 2 aliphatic amines, aniline, triidine, diphenylamine,
Aromatic, alicyclic and heterocyclic amines such as cyclohexylamine, piperidine, ethylenediamine, propylenediamine, hexamethylenediamine, o-, m-, p
-Phenylenediamine, 1,4-cyclohexanediamine, piperazine, diethylenetriamine, 4,4 ', 4 "-
Aliphatic, aromatic, alicyclic and heterocyclic polyamines such as methylidyne trianiline. Examples of the mercapto group-containing compound include aliphatic mercaptans such as methyl-, ethyl-, propyl- and butyl-, aromatic mercaptans such as benzyl mercaptan, ethylene dithioglycol, xylylene dimercaptan, mercaptoethanol and the like.

Examples of the Lewis acid of the catalyst used in the present invention include boron trifluoride, phosphorus pentafluoride, antimony pentafluoride, antimony pentachloride, aluminum chloride, titanium tetrachloride, tin tetrachloride, and other metal or non-metal halides. To be Examples of the solid acid include silicon dioxide, titanium dioxide, zirconium dioxide, aluminum oxide, and heteropoly acid. Further, examples of the form when these catalysts are used include complexes of boron trifluoride, antimony pentachloride and the like with chain and cyclic ethers such as diethyl ether and tetrahydrofuran.

A preferred polymerization reaction temperature for carrying out the present invention is 100.
℃ or less, particularly preferably -20 ℃ ~ 60 ℃,
The optimum temperature is determined depending on the kind of the initiator, the amount used, the quality of the desired polymer, the molecular weight, etc., and is usually 0 ° C to 60 ° C. The polymerization reaction can be carried out in an inert organic solvent. In bulk polymerization at a relatively low temperature, crystallization tends to occur as the polymerization progresses, so it is preferable to carry out in an inert organic solvent such as benzene, toluene, xylene. 100 ° C
At a temperature exceeding 1, the molecular weight distribution is extremely widened and the quality deterioration due to side reaction, for example, coloration is remarkable. On the other hand, the polymerization reaction time is related to the reaction rate and changes depending on the temperature, the type of initiator, the amount used, and the like. Generally, it is set to 2 to 10 hours or more. In this polymerization system, it is preferable to carry out the polymerization until the unreacted lactone disappears, in order to simplify the purification operation of the polymer and improve the quality, and it is necessary to carry out aging sufficiently.

In the present invention, the polymerization reaction completed liquid is obtained by removing the catalyst component by a known method such as alkali neutralization-washing with water or adsorption filtration to purify the polymer.
It is also possible to use an inert organic solvent as described above in the purification step, and these are distilled and recovered and reused.

The lactone polymer obtained by the method of the present invention is w /
n = 1.0 to 1.2, which is close to monodisperse, does not contain a low polymer, and has a low viscosity. Therefore, it is very useful as a raw material for spandex, urethane elastomer, urethane adhesive, urethane paint, polyester elastomer, etc. in terms of physical properties, processability, handling and the like.

(Example) Next, the present invention will be described in more detail with reference to examples.
The following examples do not limit the present invention in any case.

The yield in the examples is percent by weight and the hydroxyl number is in units of mgKOH / g according to the pyridine-acetic anhydride method. In addition, gel permeation chromatography (GP
C) uses high performance liquid chromatography (8000 series) manufactured by Toyo Soda Industry Co., Ltd., column: TSK-G2500HX / G400
It was carried out under the conditions of 0HX, solvent; tetrahydrofuran. GPC
Number average molecular weight (n), weight average molecular weight (w)
Based on a commercially available polyethylene glycol standard reagent,
Furthermore, the ratio of w and n showing the molecular weight distribution was determined. 60 ° C
The bulk viscosity in was measured with an E-type viscometer manufactured by Tokyo Keiki.

Example 1 A 500 cc four-necked separable flask was charged with 114 g (1 mol) of ε-caprolactone and 4.5 g (0.05 mol) of 1,4-butanediol, and a thermometer, a N ₂ seal, and a stirrer were attached and mixed with stirring. It was kept at 20 ° C in a constant temperature bath. To this, 3.5 g (0.025 mol) of boron trifluoride-tetrahydrofuran complex was added by a 50 cc dropping funnel, and then reacted at 20 ° C. for 5 hours. Next, 100 cc of toluene and 20 g of diatomaceous earth were added to this reaction mixture.
Was added and mixed well, and the mixture was filtered with a filter aid. Toluene was removed from the filtrate by vacuum distillation to obtain 112 g of polymer.
I got The analysis results are shown in Table-1.

Examples 2 to 4 and Comparative Example Polymerization reaction temperature is 40 ° C., 60 ° C., 80 ° C., 120 ° C. (Comparative Example)
Polymerization reaction was carried out under the same conditions and operations as in Example 1, except that The analysis results of the obtained polymer are summarized in Table 1.

As is clear from the above, the polymer obtained in the present invention had a distribution of 1.06 to 1.20 and was extremely excellent in viscosity and color number.

According to the production method of the present invention, the _w / _n value of the obtained lactone polymer is 1.0 to 1.2, which is close to monodisperse and therefore has a low viscosity. As a result, it has become possible to improve the physical properties, processability, handling, etc., which are problems that conventional lactone polymers have as raw materials for polyurethane and polyester.

Claims (2)

(57) [Claims] 1. A general formula (In the formula, R represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and n represents an integer of 4 to 5.) A lactone represented by an organic compound having at least one active hydrogen atom A method for producing a monodisperse lactone polymer, which comprises polymerizing at a temperature of 100 ° C. or lower in the presence of a Lewis acid or a solid acid as a catalyst. 2. The method according to claim 1, wherein the active hydrogen atom-containing compound is a compound containing a hydroxyl group, an amino group and a mercapto group.