JPH0471945B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for obtaining polyester glycol by ring-opening polymerization of lactone, and more specifically, the present invention relates to a method for obtaining polyester glycol by ring-opening polymerization of lactone. The present invention relates to a method for producing polyester glycol, which comprises ring-opening polymerization of valerolactone. Conventionally, polyester glycols having hydroxyl groups at the terminals obtained by ring-opening polymerization of kraton using a compound having two active hydrogen atoms as an initiator have been used as raw materials for polyurethanes, polyester elastomers, and the like.
As a typical compound thereof, polyester glycol obtained by ring-opening polymerization of ε-caprolactone is used in large quantities today as a raw material for the above polymer. However, polyester glycol obtained by ring-opening polymerization of ε-caprolactone is solid at room temperature and has a problem in ease of handling. In addition, polymer compounds such as polyurethane and polyester elastomer that are obtained using polyester glycol obtained by ring-opening polymerization of kraton as a raw material are generally compared to those made from polyester glycol obtained by condensation polymerization of dicarboxylic acid and diol. Although it has excellent hydrolysis resistance, it is still not sufficient, and when products manufactured from this product are used for a long period of time, hydrolysis occurs and the surface of the polymer compound becomes sticky. This will cause rusting and cracks on the surface. The present inventors conducted research on polyester glycol, which is easy to handle and from which a polymer compound with extremely excellent hydrolysis resistance can be obtained. A lactone-based polyester obtained by ring-opening addition polymerization of β-methyl-δ-valerolactone to a glycol represented by a hydrocarbon group having 2 to 10 carbon atoms in the main chain which may be substituted with a group. It has been found that glycols can achieve the above objectives. Poly(ε-caprolactone) glycol obtained by ring-opening polymerization of ε-caprolactone (hereinafter referred to as
PCL) and polyester glycols obtained by condensation polymerization of dicarboxylic acids and diols are generally solid at room temperature.
β-methyl-δ-valerolactone polyester glycol (hereinafter referred to as PMVL) obtained by the method of the present invention
) is a liquid that is fluid at room temperature, and is far superior to PCL and other polyester glycols in terms of ease of handling. Furthermore, in terms of hydrolysis resistance, PMVL is
Compared to PCL and other polyester glycols,
When made into a polymer compound such as polyurethane or polyester elastomer, it has extremely good hydrolysis resistance. It is already known that polyester can be obtained by ring-opening polymerization of β-methyl-δ-valerolactone alone in the presence of a catalyst (Japanese Patent Publication No. 40-23917). One terminal group is a hydroxyl group and the other is a carboxyl group, so it can be used as a plasticizer for vinyl resins and adhesives, but since both terminals do not have hydroxyl groups, it cannot be used as a raw material for polyurethane, polyester elastomers, etc. do not have. In addition, polyester glycols obtained by ring-opening addition polymerization of alkyl-substituted -δ-valerolactone to glycol include ring-opening addition polymerization of γ.γ-dimethyl-δ-valerolactone to 1,4-butanediol. Although things are known (Industrial
and Engineering Chemistry，Product
Research Development, Vol. 13, No. 3, 1974, 193
), this polyester glycol is fixed at room temperature as specified in the above-mentioned literature, and polyurethane produced using this polyester glycol as one component has a higher elongation than other polyester-based polyurethanes. Because it has a low polyurethane content and is crystalline, it cannot be said to be suitable as a polyurethane that requires properties as an elastomer. In contrast, the method of the present invention obtains
Polyurethane produced using PMVL as one component is amorphous and is not inferior to other polyurethanes in terms of mechanical properties such as elongation. Furthermore, JP-A-55-104315 describes polyester glycol obtained by ring-opening polymerization of lactone to a compound having an active hydrogen atom. β used in the method of the present invention among
Compounds similar to -methyl-δ-valerolactone are β-ethyl-δ-valerolactone and δ-valerolactone without a substituent, β-ethyl-δ-valerolactone.
There is no mention of δ-valerolactone,
Moreover, the same publication does not contain any information regarding the properties of polyester glycols derived from these δ-valerolactones, and it goes without saying that PMVL is liquid at room temperature and that the polymers obtained from PMVL are extremely resistant to hydrolysis. There is no mention of high prices, etc. In addition, methyl-δ-valerolactone includes α-methyl form, β-methyl form, γ-methyl form,
There are four types of δ-methyl forms, but among these, only polyester glycol derived from β-methyl-δ-valerolactone has excellent hydrolysis resistance when made into a polymer compound such as polyurethane. As described above, PMVL is not only a completely new polyester glycol, but also has excellent features that cannot be predicted from the prior literature. β-Methyl-δ-valerolactone used in the method of the present invention is obtained by hydroformylating 3-methyl-3-buten-1-ol as already proposed by some of the present inventors, and the resulting 2-hydroxy- 4
-It can be easily obtained by further dehydrogenating methyltetrahydropyran (Japanese Patent Application No. 134752/1982). Also, 3-methyl-1,5-
It can also be obtained from pentanediol by a known oxidative dehydrogenation reaction. In the present invention, there are many glycols represented by the above general formula, but specifically, ethylene glycol, propylene glycol, 2-methyl-1,3-propanediol,
1,4-butanediol, 1,3-butanediol, 1,5-pentanediol, 3-methyl-
Examples include 1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol, 1,10-decanediol, neopentyl glycol, and the like. In particular, ethylene glycol, propylene glycol, 1,4-butanediol, 1,5-
Pentanediol, 3-methyl-1,5-pentanediol, and the like are preferred in terms of ease of handling. By adjusting the molar ratio of β-methyl-δ-valerolactone and the glycol represented by the above general formula, it is possible to arbitrarily change the molecular weight of PMVL. However, as a raw material for polyurethane and polyester elastomer,
Since the average molecular weight of PMVL is preferably in the range of 300 to 10,000, the ratio of β-methyl-δ-valerolactone and the glycol represented by the above general formula should be determined based on 1 mole of the glycol. The amount of δ-valerolactone is selected to be within the range of about 2.5 to 90 moles. As a matter of course,
As the proportion of β-methyl-δ-valerolactone used increases, the average molecular weight of the produced PMVL increases. When the average molecular weight of PMVL is less than 300, when a polymer compound such as polyurethane is produced using this polyester glycol, the resulting polymer compound has poor low-temperature properties and does not have rubber elasticity. Become something. On the other hand, if the average molecular weight exceeds 10,000, the resulting polymeric material will have poor oil resistance and will have poor strength properties when made into a film. In the present invention, ε-caprolactone or other kratones can also be used in an amount within 50 mol % of the β-methyl-δ-valerolactone used. If the proportion of these lactones used exceeds 50 mol%, it is not preferable because the above-mentioned excellent features of the polyester glycol of the present invention are lost. PMVL is obtained by ring-opening addition polymerization of β-methyl-δ-valerolactone to the glycol represented by the above general formula, but this reaction is usually carried out in the presence of a catalyst. The catalysts used include known catalysts used for ring-opening polymerization of lactones, such as mineral acids such as sulfuric acid and phosphoric acid, lithium,
Alkali metals such as sodium and potassium, alkyl metal compounds such as n-butyllithium, and the like are used. Catalyst is usually 0.001 to lactone
It is desirable to use it within the range of 10 mol%.
Further, this reaction is carried out under an inert gas atmosphere such as nitrogen, helium, argon, or the like. Prior to carrying out this reaction, it is desirable that the moisture content of β-methyl-δ-valerolactone and the glycol represented by the above general formula be reduced as much as possible. The reaction is usually carried out at a temperature of 0°C or higher, but since PMVL cannot necessarily be said to be thermally stable, a temperature condition not exceeding 200°C is preferred. The reaction time is usually selected from a range of about 10 minutes to 50 hours. Further, although the reaction is usually carried out in the absence of a solvent, a solvent inert to the reaction can also be used. Depending on the type of catalyst used to produce PMVL, it may impair the stability of PMVL during storage or cause undesirable side reactions during subsequent production of polymeric materials using PMVL. Because there are things that can cause
It is desirable to wash the PMVL with water to remove catalyst material. In that case, preferably
A method is used in which PMVL is dissolved in a solvent that is immiscible with water, such as chloroform or ether, the solution is washed with water, and after separation, the solvent and water are removed, preferably under reduced pressure. As mentioned above, PMVL obtained by the method of the present invention can be used not only as a raw material for polyurethane and polyester elastomer, but also as a plasticizer for polymeric substances. The present invention will be specifically explained below using Examples. Example 1 A 300 ml separable flask equipped with a stirring device, a dropping funnel, and a gas inlet/outlet was sufficiently purged with dry nitrogen gas, and then 4.30 g of ethylene glycol and 0.09 g of metallic sodium were added to the flask.
was prepared and immersed in a 70°C bath while stirring to completely dissolve the metallic sodium. After that, while keeping the temperature of the bath at 40℃ and stirring vigorously, β-
150 g of methyl-δ-valerolactone was added at once from the dropping funnel. The viscosity of the solution increased immediately. After 1 hour, the stirring was stopped, and the contents of the flask were taken out and dissolved in 600 ml of purified chloroform at room temperature, followed by a washing operation by adding 600 ml of distilled water at the same temperature. After separation, the washing operation was repeated again with 600 ml of distilled water. The chloroform layer was separated and obtained by rotary evaporation at 70°C.
Chloroform and trace amounts of water were completely distilled off under reduced pressure at °C. Through this operation, 133 g of a colorless and transparent viscous liquid was obtained. As measured by 1H-NMR, unreacted β-methyl-δ-
No valerolactone-based absorption was observed. Also, from the chemical shift of 1H-NMR,
This liquid consists of ethylene glycol and β-methyl-
It was confirmed that δ-valerolactone is a polyester glycol obtained by ring-opening addition polymerization. Next, 5 g of this polymer was added to 25 ml of acetic anhydride-pyridine solution (volume ratio 1/9), and the mixture was heated at 90°C for 2 hours.
After heating for a period of time, the hydroxyl value was measured by titration using a conventional method and found to be 48.4. In addition, 5 g of this polymer was added to diethyl ether.
It was dissolved in 40 ml of ethanol (volume ratio 1/1) and the acid value was measured by a conventional method and found to be 0.27. From this, the molecular weight of this polymer is calculated to be 2327. In addition, the ratio of the weight average molecular weight to the number average molecular weight (M/
m) was 1.46. Examples 2 to 4 By the same operation as in Example 1, the presence of the initiator and catalyst described in Table 1 under the conditions of the molar ratio of the initiator and β-methyl-δ-valerolactone described in Table 1 PMVL was synthesized below. All of the polymers obtained were colorless viscous liquids.
Table 1 shows the hydroxyl value, acid value, and molecular weight calculated from these values of the polymer.

[Table] Example 5 β-methyl-δ was added to the flask used in Example 1.
- After 150 g of valerolactone and 4.5 g of ethylene glycol were charged and the inside of the flask was sufficiently purged with dry nitrogen gas, the flask was immersed in a bath at 40°C, and 0.4 ml of sulfuric acid was added with vigorous stirring.
After 5 hours, stirring was stopped, and the obtained polymer was washed with water and dried in the same manner as in Example 1. Through this operation, a colorless and transparent viscous polymer was obtained. The acid value of this polymer was 0.51, and the hydroxyl value was 53.1 (molecular weight: 2130). Example 6 Polyester was produced in the same manner as in Example 1, except that a mixture of 100 g of β-methyl-δ-valerolactone and 50 g of ε-caprolactone was used in place of 150 g of β-methyl-δ-valerolactone. Synthesized glycol. The resulting polymer is a colorless, viscous liquid;
It did not crystallize even after long-term storage at room temperature. The hydroxyl value and acid value of the obtained polymer are respectively
They were 48.1 and 0.29. Reference Example Polyurethane was produced using PMVL obtained in Example 1, and polycaprolactone (molecular weight
2300, acid value 0.21, hereinafter abbreviated as PCL) in terms of hydrolysis resistance. That is, PMVL or PCL and PMVL or PCL
4,4'-diphenylmethane diisocyanate in an amount of 5 moles relative to the total amount was reacted at 60°C under nitrogen. The obtained prepolymer was dissolved in dimethylformamide to a concentration of 25% by weight. next,
1,4 times 4 moles of PMVL or PCL
-Butanediol was added to the above prepolymer solution and reacted by stirring at 70°C for 10 hours to obtain a dimethylformamide solution of polyurethane. After adjusting the polyurethane concentration of this solution to 10% by weight, this solution was cast onto a glass plate, dried and thickened.
A dry coating of 50μ was obtained. I got it like this
The hydrolysis resistance of polyurethanes containing PMVL and PCL as one component was compared by the following young angle test. That is, the above polyurethane film was left at 70°C and 95% relative humidity for 28 days,
Hydrolysis resistance was evaluated based on the tensile strength retention of the film before and after the Youngle test. As a result, the strength retention rate of polyurethane made from PMVL was 81%, while that of polyurethane made from PCL was only 34%. Thus, it can be seen that the hydrolysis resistance of polyurethane made from PMVL is extremely superior to that of conventional polyurethane made from PCL. Comparative Reference Examples 1 and 2 Specified lactone-based polyester glycol (initiator: ethylene glycol; lactone raw material: α-
Methyl-δ-valerolactone or γ-methyl-
δ-valerolactone (average molecular weight: about 2000) was reacted with 4,4'-diphenylmethane diisocyanate in an amount 5 times the mole of the lactone polyester glycol under nitrogen at 60°C. The obtained prepolymer was dissolved in dimethylformamide to a concentration of 25% by weight. Next, 4 times the mole of 1,
4-Butanediol was added to the above prepolymer solution and reacted by stirring at 70°C for 10 hours to obtain a dimethylformamide solution of polyurethane. After adjusting the polyurethane concentration of this solution to 10% by weight, this solution was cast onto a glass plate, dried and thickened.
A dry coating of 50μ was obtained. The obtained polyurethane film was left for 28 days at a temperature of 70°C and a relative temperature of 95%. The hydrolysis resistance of polyurethane was evaluated based on the tensile strength retention rate of the polyurethane film before and after this jungle test.
The evaluation results are shown in Table 2.

【table】

Claims (1)

[Claims] 1 General formula HO-R-OH (where R has 2 to 2 carbon atoms in the main chain, which may be substituted with a lower alkyl group)
A method for producing a lactone-based polyester glycol, which comprises carrying out ring-opening addition polymerization of β-methyl-δ-valerolactone to a glycol represented by 10 (representing a hydrocarbon group).