JPH0357932B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a novel polyalkylene ether glycol copolymer. More specifically, the present invention relates to a novel method for producing a polyalkylene ether glycol copolymer, which comprises ring-opening copolymerization of a mixture of 3-methyloxetane and tetrahydrofuran under an acid catalyst.

Conventionally known polyalkylene ether glycols include polyethylene glycol, poly-
1,2- and 1,3-propylene ether glycol, polytetramethylene ether glycol, polyhexamethylene ether glycol, and their copolymers are known, and are useful in operations such as rubber molding, textiles, ceramics, and metal processing. Used as various lubricants and raw materials for industrial use, as important raw materials for cosmetics and pharmaceutical manufacturing, and as raw materials and additives for water-based paints, paper coatings, adhesives, cellophane, printing inks, abrasives, and other surfactants. It is widely used as an agent and as a raw material for resins such as alkyd resins.

On the other hand, in recent years, unlike elastic bodies such as rubber (hereinafter referred to as elastomers) produced by conventional chemical crosslinking,
Thermoplastic elastomers, which have a structure that exhibits elastic properties incorporated into their molecules from the beginning, have been developed and are now widely put into practical use. Thermoplastic elastomers have many features such as simplified processing methods, shortened processing times, ease of scrap use, and ease of developing a wide range of mechanical properties ranging from hard to soft. It is an elastomer that is expected to develop in the future to fill the gap between plastic plastics, thermosetting plastics, and vulcanized rubber. Thermoplastic elastomers currently on the market are broadly classified into poly(styrene-butadiene), polyester, polyacid, polyurethane, and blends of ethylene-propylene copolymer rubber and polypropylene. With the exception of the blend system, all of these copolymers are typical block copolymers in which a soft elastic segment (soft segment) and a hard segment (hard segment) are woven into a linear structure in a block manner during polymerization. As a compound used for such a soft segment, polyalkylene ether glycol is often used in elastomers such as polyester, polyamide, and polyurethane. This is because polyalkylene ether glycol has hydroxyl groups at both ends, so it is easy to form carboxyl groups, isocyanate groups,
Because they react with amino groups to form ester bonds, urethane bonds, and amide bonds, and their skeletons are connected by ether bonds, the resulting polymer has excellent elasticity, low-temperature properties, hydrolysis resistance, salt water resistance, This is because it has advantages such as excellent bacterial resistance. However, the function of polyalkylene ether glycol as a soft segment is closely related to the chemical structure and physical properties of polyalkylene ether glycol. From the viewpoint of this, it is desirable that the hydroxyl groups at both terminals are both primary, and from the viewpoint of elasticity and elastic recovery, it is desirable that the glass transition temperature is low and that it does not crystallize itself even if the molecular weight is high. . However, among the known polyalkylene ether glycols, there is no known glycol that has both such chemical structure and physical properties. For example, polyethylene glycol and polytetramethylene ether glycol, which are often used as soft segments, have primary hydroxyl groups at both ends and are highly reactive, but when the molecular weight increases to about 1500 or more, they crystallize themselves. It becomes impossible to fully demonstrate its function as a soft segment. On the other hand, polypropylene ether glycol and the like are difficult to crystallize even when the molecular weight is high, but one of the terminal hydroxyl groups is secondary and has the disadvantage of poor reactivity. However, polyalkylene ether glycol is known, which is obtained by copolymerizing propylene oxide and ethylene oxide and has primary hydroxyl groups at both ends and is difficult to coagulate even with high molecular weight, but due to its chemical structure, the carbon chain of the repeating unit is rigid. Therefore, sufficient elasticity and elastic recovery effects as a soft segment cannot be exhibited.

As a result of intensive research in view of the current situation, the present inventors have found that a novel polyalkylene ether glycol can be easily produced by ring-opening copolymerization of a mixture of 3-methyloxetane and tetrahydrofuran under an acid catalyst. The present invention has been based on this discovery.

That is, the polyalkylene ether glycol copolymer obtained by the present invention has a 2-methylenepropylene ether group and a tetramethylene ether group as repeating units, and has primary hydroxyl groups at both ends. Therefore, it has a very flexible chemical structure and is difficult to crystallize even with high molecular weight.
It is a new polyalkylene ether glycol copolymer that can fully exhibit the effects of elasticity and elastic recovery, and also easily reacts with carboxyl groups, isocyanate groups, amino groups, etc., and is useful in elastomers such as polyester, polyamide, and polyurethane. Suitable as a soft segment.

The novel polyalkylene ether glycol copolymer of the present invention can be easily obtained by ring-opening copolymerization of 3-methyloxetane and tetrahydrofuran under an acid catalyst. The reaction ratio between 3-methyloxetane and tetrahydrofuran is not particularly limited, but is preferably a molar ratio of 1:99 to 99:1, more preferably 99 to 10:1 to 90. The present production method is characterized in that 3-methyloxetane and tetrahydrofuran are liquid at room temperature, so they are easy to handle, and the ring-opening copolymerization reaction under an acid catalyst proceeds easily.

Also, random or block copolymers can be obtained depending on the polymerization method.

3-Methyloxetane used in the present invention is produced by, for example, using 2-methyl-1,3-propanediol as a starting material and reacting it with acetyl chloride.
After obtaining 3-chloro-2-methylpropyl acetate, it is obtained by ring closure under alkali melting. In addition, the acid catalyst for ring-opening copolymerization used is:
HCl, HBr, H ₂ SO ₄ , H ₃ PO ₄ , HClO ₄ , acetic acid,
Hydrogen acid catalysts such as chlorosulfonic acid, florsulfonic acid, and benzenesulfonic acid may be used.

The polyalkylene ether glycol copolymer with a molecular weight of less than 1500 obtained by the present invention can be used not only as a soft segment for elastomers such as polyester, polyamide, and polyurethane, but also for various applications where conventional polyalkylene ether glycols are used. Lubricants and their raw materials, cosmetics, raw materials for pharmaceutical manufacturing, water-based paints,
It can also be widely used as a raw material or additive for paper coatings, adhesives, cellophane, printing inks, abrasives, surfactants, etc., and as a raw material for resins such as alkyd resins.

EXAMPLES The present invention will be described in detail below with reference to Examples, but the present invention is not limited thereto. In addition,
Parts in the examples mean parts by weight, and the substances were identified by the following measurement method.

1 Nuclear magnetic resonance spectrum JEOL, nuclear magnetic resonance apparatus JNM-C-
Measured using 60HL.

2 Infrared absorption spectrum Diffraction grating infrared spectrophotometer IRA- manufactured by JASCO Corporation
2 was used for measurement.

3 Hydroxyl value Measured according to Japanese Industrial Standard K1557.

Example 1 100 parts of 2-methyl-1,3-propanediol and 101 parts of acetyl chloride were mixed and heated at 100°C for 8 hours to obtain 151 parts of 3-chloro-2-methylpropyl acetate in a yield of 90%. Ta. Furthermore, 3-chloro-
When 100 parts of 2-methylpropyl acetate was treated under a potassium hydroxide-sodium hydroxide solution, 31 parts of ring-closed 3-methyloxetane was obtained in a yield of 58%. 3-Methyloxetane 15 thus obtained
85 parts of tetrahydrofuran purified by distillation, 70%
Mix 2 parts of perchloric acid and cool the reaction vessel with dry ice-methanol cryogen while stirring, and adjust the internal temperature to -10 to -15°C. Next, slowly drop 10 parts of 28% oleum. After the addition is complete, the reaction mixture is kept at -10°C for 24 hours. 50 parts of distilled water and 100 parts of a 5% by weight aqueous sodium hydroxide solution are sequentially added to this, and the mixture is heated under reflux for 1 hour. The reaction mixture is transferred to a separatory funnel and the organic layer (upper layer) and aqueous layer are separated. Then use n-butanol to
After extraction from the recycled aqueous layer, it is combined with the organic layer and dried. Furthermore, n-butanol was distilled off using an evaporator to obtain 71 parts of a transparent oil with a yield of 71%.

The infrared absorption spectrum and nuclear magnetic resonance spectrum of the polyether copolymer thus obtained are shown in FIG. 1 and FIG. 2, respectively. The structure and composition of the obtained copolymer was determined by elemental analysis, infrared absorption spectrum, and nuclear magnetic resonance spectrum to be a copolymer containing 19 mol% of 2-methyl-propylene ether groups and 81 mol% of tetramethylene ether groups. It was confirmed.

The average molecular weight calculated from the hydroxyl value was 970.

Elemental analysis Actual value Calculated value C 65.27% 65.40% H 11.21% 11.18% Example 2 35 parts of 3-methyloxetane obtained in the same manner as Example 1 and 65 parts of tetrahydrofuran purified by distillation
1 part and 2 parts of 70% perchloric acid, and while stirring, cool the reaction vessel with a dry ice-methanol cryogen, and adjust the internal temperature to -10 to -15°C. Next, slowly drop 15 parts of 28% oleum. After the addition is complete, the reaction mixture is kept at -10°C for 24 hours. Termination of the reaction and purification were carried out in the same manner as in Example 1 to obtain 69 parts of a transparent oily substance in a yield of 69%.

The composition of the polyether copolymer thus obtained was confirmed by nuclear magnetic resonance spectroscopy to be a copolymer containing 47 mol% of 2-methyl-propylene ether groups and 53 mol% of tetramethylene ether groups. . The infrared absorption spectrum was not significantly different from Example 1.

The average molecular weight calculated from the hydroxyl value was 1430.

Elemental analysis Actual value Calculated value C 65.47% 65.79% H 11.31% 11.18%

[Brief explanation of drawings]

FIG. 1 shows an infrared absorption spectrum of the polyether copolymer obtained in Example 1, and FIG. 2 shows its nuclear magnetic resonance spectrum.

Claims (1)

[Claims] 1 A mixture of 3-methyloxetane and tetrahydrofuran in a molar ratio of 99 to 10:1 to 90 under an acid catalyst,
A method for producing a novel polyalkylene ether glycol copolymer having a molecular weight of less than 1500, which is characterized by carrying out ring-opening copolymerization.