JP7682006B2 - Polycarbonate diol and its manufacturing method - Google Patents

Description

The present invention relates to a polycarbonate diol and a method for producing the same.

When polycarbonate diol is industrially produced from diol and carbonate compounds, a transesterification catalyst is generally used. The transesterification catalyst remains in the polycarbonate diol, and when the polycarbonate diol is used as a raw material for polyurethane, thermoplastic elastomer, urethane elastic fiber, etc., it promotes the reaction with isocyanate, making it difficult to control the urethane reaction. For example, when a highly reactive isocyanate compound such as diphenylmethane diisocyanate or naphthalene diisocyanate is used, it becomes extremely difficult to control the urethane reaction, and problems such as high molecular weight and gel formation occur. To completely prevent this, there is a method of separating the transesterification catalyst using an adsorbent, but the process is complicated and there are problems with carrying out this industrially.

Various treatment methods have been disclosed to reduce the effect of the transesterification catalyst on the urethane reaction. For example, a method for producing an aliphatic polycarbonate diol is known, which is characterized by using a phosphoric acid monoester and a phosphoric acid diester in combination with an aliphatic polycarbonate diol polymerized using a transesterification catalyst, dissolving the phosphoric acid monoester and the phosphoric acid diester in a polar solvent in advance, and adding the resulting solution in the polar solvent (see, for example, Patent Document 1). Also known is a polycarbonate diol product containing phosphoric acid and/or phosphorous acid, which is obtained by transesterification in the presence of a transesterification catalyst using a dihydroxy compound and a carbonate compound as raw material monomers (see, for example, Patent Document 2).

Patent No. 4749024 Patent No. 6526943

However, while the method of Patent Document 1 can suppress the effect of the transesterification catalyst on the urethane reaction, depending on the ratio of the phosphoric acid monoester and phosphoric acid diester, the urethane reactivity may change, for example, after three years or more have passed since production. Also, the method of Patent Document 2 has the problem that depending on the amount of phosphoric acid, its corrosiveness limits the material of the reactor.

The present invention aims to reduce the effect of the transesterification catalyst used in the production of polycarbonate diol on the urethane reaction (i.e., excessive promotion of the urethane reaction) and to supply a polycarbonate diol whose urethane reaction reactivity is unlikely to change over time.

As a result of intensive research into solving the above problems, the inventors have discovered that the above problems can be solved by using a specific phosphorus compound in a specific amount and ratio.

That is, the present invention includes the following embodiments.
[1]
A polycarbonate diol polymerized using a transesterification catalyst;
A phosphoric acid monoester represented by the following formula (a),
A phosphoric acid diester represented by the following formula (b),
A phosphate triester represented by the following formula (c),
mixing and heating;
Including,
the ratio of the number of moles of phosphorus to the number of moles of the transesterification catalyst is 0.1 to 5;
The mass ratio of the phosphoric acid monoester, the phosphoric acid diester, and the phosphoric acid triester is
50-90: 3-25: 0.01-5
(Phosphate monoester: Phosphate diester: Phosphate triester)
Satisfy the relationship
Method for producing polycarbonate diol
[In the formula,
R ¹ is an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms,
^R2 's are each independently an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms;
Each ^R3 is independently an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms.
[2]
The mixing step further comprises mixing phosphoric acid;
The mass ratio of the phosphoric acid monoester, the phosphoric acid diester, the phosphoric acid triester, and the phosphoric acid is
50-90: 3-25: 0.01-5: 3-25
(Phosphate monoester: Phosphate diester: Phosphate triester: Phosphate)
Satisfy the relationship
The manufacturing method described in [1].
[3]
The heating is carried out at 70° C. to 170° C. for 15 minutes to 5 hours;
The manufacturing method according to [1] or [2].
[4]
In the mixing, the phosphoric acid monoester, the phosphoric acid diester, the phosphoric acid triester, and the phosphoric acid are dissolved in a solvent having an SP value of 8.0 to 11.0 (cal/cm ³ ) ^1/2 and mixed as such.
The manufacturing method according to [2] or [3].
[5]
A polycarbonate diol polymerized using a transesterification catalyst;
A phosphoric acid monoester represented by the following formula (a),
A phosphoric acid diester represented by the following formula (b),
A phosphate triester represented by the following formula (c),
Including,
the ratio of the number of moles of phosphorus to the number of moles of the transesterification catalyst is 0.1 to 5;
The mass ratio of the phosphoric acid monoester, the phosphoric acid diester, and the phosphoric acid triester is
50-90: 3-25: 0.01-5
(Phosphate monoester: Phosphate diester: Phosphate triester)
Satisfy the relationship
Polycarbonate Diol
[In the formula,
R ¹ is an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms,
^R2 's are each independently an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms;
Each ^R3 is independently an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms.
[6]
Further comprising phosphoric acid,
The mass ratio of the phosphoric acid monoester, the phosphoric acid diester, the phosphoric acid triester, and the phosphoric acid is
50-90: 3-25: 0.01-5: 3-25
(Phosphate monoester: Phosphate diester: Phosphate triester: Phosphate)
Satisfy the relationship
The polycarbonate diol according to [5].

According to the present invention, it is possible to reduce the effect of the transesterification catalyst used in the production of polycarbonate diol on the urethane reaction, and further to supply polycarbonate diol whose urethane reaction reactivity is unlikely to change over time.

The following is a detailed description of the embodiment of the present invention (hereinafter, abbreviated as "present embodiment"). Note that the present invention is not limited to the following embodiment, and can be modified in various ways within the scope of the gist of the invention.

<Polycarbonate diol and its manufacturing method>
One embodiment of the present invention includes a step of mixing a polycarbonate diol polymerized using an ester exchange reaction catalyst, a phosphoric acid monoester represented by the following formula (a) (hereinafter also referred to as "phosphoric acid monoester (a)"), a phosphoric acid diester represented by the following formula (b) (hereinafter also referred to as "phosphoric acid diester (b)"), and a phosphoric acid triester represented by the following formula (c) (hereinafter also referred to as "phosphoric acid triester (c)"), and heating the mixture,
the ratio of the number of moles of phosphorus to the number of moles of the transesterification catalyst is 0.1 to 5;
The present invention relates to a method for producing a polycarbonate diol, in which the mass ratio of the phosphoric acid monoester, the phosphoric acid diester, and the phosphoric acid triester satisfies the relationship of 50-90:3-25:0.01-5 (phosphoric acid monoester:phosphoric acid diester:phosphoric acid triester), and a polycarbonate diol produced by the method.
[In the formula,
R ¹ is an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms,
^R2 's are each independently an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms;
Each ^R3 is independently an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms.

The polycarbonate diol obtained by the manufacturing method of this embodiment can reduce the effect of the transesterification catalyst on the urethane reaction, and can also suppress changes in urethane reaction reactivity over time.

In this specification, the phosphoric acid monoester (a), the phosphoric acid diester (b) and the phosphoric acid triester (c) are collectively referred to as "phosphate esters", and the phosphoric acid esters and other phosphorus-containing compounds are collectively referred to as "phosphorus compounds".

R ¹ to R ³ in formulas (a) to (c) are each independently an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms, preferably an alkyl group having 3 to 12 carbon atoms, and more preferably an alkyl group having 3 to 8 carbon atoms. Specific examples of the alkyl group include methyl, ethyl, propyl, isopropyl, n-butyl, n-hexyl, 2-ethylhexyl, octyl, lauryl, stearyl, isodecyl, etc. Specific examples of the aryl group include phenyl, etc.

The mass ratio of the phosphoric acid monoester (a), phosphoric acid diester (b), and phosphoric acid triester (c) used in the manufacturing method of this embodiment satisfies the relationship of 50-90:3-25:0.01-5. When the phosphoric acid esters satisfy this relationship, the influence of the transesterification catalyst on the urethane reaction is reduced and the effect is sustained over time. The mass ratio of the phosphoric acid monoester (a) is preferably 60-85. The mass ratio of the phosphoric acid diester (b) is preferably 5-20.

In the manufacturing method of this embodiment, phosphoric acid may be mixed in addition to the phosphoric acid ester. When phosphoric acid is mixed, it is preferable that the mass ratio of the phosphoric acid monoester (a), the phosphoric acid diester (b), the phosphoric acid triester (c), and the phosphoric acid satisfy the relationship of 50-90: 3-25: 0.01-5: 3-25. If the mass ratio of phosphoric acid is 3 or more, the influence of the transesterification reaction catalyst on the urethane reaction can be efficiently reduced in combination with the phosphoric acid ester. If the mass ratio of phosphoric acid is 25 or less, the reactor is less corroded. The mass ratio of phosphoric acid is preferably 5 to 20.

The ratio of the number of moles of phosphorus to the number of moles of the transesterification catalyst is 0.1 to 5, preferably 0.5 to 3.5, and more preferably 0.5 to 2.5. The phosphorus in the "number of moles of phosphorus" is not limited to phosphorus derived from phosphate esters, but also includes, for example, phosphorus derived from phosphoric acid. If the ratio is 0.1 or more, the effect of the transesterification catalyst on the urethanization reaction can be reduced. If the ratio is 5 or less, the promotion of the urethanization reaction due to excess phosphorus can be suppressed. The ratio is calculated from the analytical values of the catalyst metal and phosphorus obtained by elemental analysis using inductively coupled plasma (ICP) as described in the examples below.

The amount of transesterification catalyst in the aliphatic polycarbonate diol can be calculated based on the amount of catalyst charged when heat treatment is performed following the production of the aliphatic polycarbonate diol, and when a commercially available polycarbonate diol is used, it is calculated by determining the amount of catalytic metal contained in the polycarbonate diol.

The compatibility of phosphorus compounds with aliphatic polycarbonate diols is not necessarily good. Depending on the phosphorus compound added, it may be difficult to disperse it in the aliphatic polycarbonate diol, and it may be necessary to increase the heat treatment temperature or extend the heat treatment time. If the phosphorus compound is dissolved or dispersed in a solvent beforehand and then added, it becomes easier for the phosphorus compound to dissolve or disperse in the aliphatic polycarbonate diol, and it becomes possible to perform the treatment at a lower heat treatment temperature for a shorter period of time than when no solvent is used.

The solvent used preferably has an SP value (solubility parameter) of 8.0 to 11.0 (cal/cm ³ ) ^1/2 . Examples of the solvent used in the present invention include 1,4-dioxane, 1-butanol, butyl acetate, ethyl acetate, acetone, 2-ethylhexanol, and diethylene glycol monobutyl ester. From the viewpoint of being less subject to restrictions on the temperature at which the solvent is added, the boiling point of the solvent is preferably 100° C. or higher, and more preferably 150° C. or higher.

In order not to affect the urethane reaction, it is preferable to use a small amount of solvent. Usually, the mass of the solvent used is 0.5 to 5 times, preferably 0.5 to 3 times, and more preferably 0.5 to 2 times the mass of the phosphorus compound.

Although the phosphorus compound can be added to the aliphatic polycarbonate diol in a state where it is dispersed in a solvent, it is more preferable to add the phosphorus compound dissolved in the solvent, since this allows a specified amount of the phosphorus compound to be added and makes it easier for the phosphorus compound to dissolve or disperse in the aliphatic polycarbonate diol.

As a method for producing the aliphatic polycarbonate diol of the present invention, a phosphorus compound may be added and heat-treated following polymerization of the aliphatic polycarbonate diol. Alternatively, a phosphorus compound may be added to an aliphatic polycarbonate diol produced without taking measures to reduce the effect of the transesterification catalyst on the urethane reaction, such as adding a phosphorus compound, and then the aliphatic polycarbonate diol may be heat-treated again.

The manufacturing method of this embodiment will be described by taking as an example a method of performing heat treatment following polymerization of an aliphatic polycarbonate diol. After a predetermined degree of polymerization is reached, a phosphorus compound calculated based on the amount of the transesterification catalyst charged is added to the reactor and heated and stirred. The heat treatment temperature is preferably 70°C to 170°C. If necessary, the phosphorus compound is added after cooling from the temperature at the end of polymerization to a predetermined heat treatment temperature. If the heat treatment temperature is 70°C or higher, the heat treatment time is not long, which is economical. If the heat treatment temperature is 170°C or lower, the aliphatic polycarbonate diol is less likely to be colored and the added phosphorus compound is less likely to decompose. If the heat treatment temperature is 75°C to 160°C, the possibility of the above problems occurring is reduced, and if it is 75°C to 155°C, it is even more preferable. The heat treatment time is the time required to achieve a predetermined urethane reaction rate, and varies depending on the heat treatment temperature and treatment method, but is usually 15 minutes to 5 hours. If the heat treatment time is 15 minutes or more, the treatment is less likely to be insufficient, and if it is 5 hours or less, there is no problem with productivity.

When the phosphorus compound is dissolved in a solvent beforehand and added to the aliphatic polycarbonate diol, the heat treatment temperature can be lowered to 70 to 150°C, and even if it is 70 to 125°C, the effect can be achieved by heat treatment for 30 minutes to 4 hours.

Because aliphatic polycarbonate diol may become discolored during heat treatment, it is preferable to replace the atmosphere in the treatment container with an inert gas such as nitrogen before treatment.

The treatment method of the present invention is not particularly limited, and for example, the mixture may be heated and stirred in a reactor equipped with a heater and a stirrer, or the mixture may be continuously heated in an in-line mixer or static mixer.

The aliphatic polycarbonate of the present invention is obtained from a dihydro compound and a carbonate compound using an ester exchange reaction catalyst.

The dihydro compound used in the method for producing polycarbonate diol of this embodiment is not particularly limited, but examples thereof include diols having no side chains, such as 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-dodecanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,13-tridecanediol, 1,14-tetradecanediol, and 1,15-pentadecanediol; 2-methyl- Examples of the diols include diols having a side chain such as 1,8-octanediol, 2-ethyl-1,6-hexanediol, 2-methyl-1,3-propanediol, 3-methyl-1,5-pentanediol, 2,4-dimethyl-1,5-pentanediol, 2,4-diethyl-1,5-pentanediol, 2-butyl-2-ethyl-1,3-propanediol, and 2,2-dimethyl-1,3-propanediol; and cyclic diols such as 1,4-cyclohexanedimethanol, 2-bis(4-hydroxycyclohexyl)-propane, and 1,4-cyclohexanediol. One or more of the diols may be used as the dihydro compound. When one or more diols having no side chains are used as dihydro compounds, the chemical resistance and mechanical strength of the coating film are increased, which is preferable. When one or more diols selected from 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, and 1,9-nonanediol are used as dihydro compounds, it is more preferable. When two diols selected from 1,4-butanediol, 1,5-pentanediol, and 1,6-hexanediol are used as raw materials for polycarbonate diol, it is even more preferable. When 1,5-pentanediol and 1,6-hexanediol are used as dihydro compounds, it is particularly preferable.

When two or more kinds of diols are used as dihydro compounds, the ratio of those diols is not particularly limited, but it is preferable to set the ratio of the raw materials used so that the resulting polycarbonate diol is liquid at room temperature. When two kinds of diols are used as raw materials, it is preferable to set the charge amount between 20/80 and 80/20 in molar ratio. If it is within this range, the resulting polycarbonate diol will be liquid. It is more preferable to set it to 30/70 to 70/30, and more preferably to set it to 40/60 to 60/40, since it will be liquid even at temperatures below 0°C.

Furthermore, compounds having three or more hydroxyl groups in one molecule, such as trimethylolethane, trimethylolpropane, hexanetriol, and pentaerythritol, can also be used as raw materials for polycarbonate diol, as long as the performance of the polycarbonate diol of this embodiment is not impaired. If too much of these compounds having three or more hydroxyl groups in one molecule are used as raw materials for polycarbonate diol, crosslinking occurs during the polymerization reaction of polycarbonate, causing gelation. Therefore, even when a compound having three or more hydroxyl groups in one molecule is used as a raw material for polycarbonate diol, it is preferable that the compound is 0.1 to 5 mol% relative to the number of moles of the diol used as a raw material for polycarbonate diol. This ratio is more preferably 0.1 to 1 mol%.

The carbonate compound used in the method for producing polycarbonate diol of this embodiment is not particularly limited, but examples thereof include dialkyl carbonates such as dimethyl carbonate, diethyl carbonate, dipropyl carbonate, and dibutyl carbonate; diaryl carbonates such as diphenyl carbonate; and alkylene carbonates such as ethylene carbonate, trimethylene carbonate, 1,2-propylene carbonate, 1,2-butylene carbonate, 1,3-butylene carbonate, and 1,2-pentylene carbonate. Among these, one or more carbonates can be used as raw materials for polycarbonate diol. From the viewpoints of ease of availability and ease of setting polymerization reaction conditions, it is preferable to use dimethyl carbonate, diethyl carbonate, diphenyl carbonate, dibutyl carbonate, and ethylene carbonate.

In the method for producing polycarbonate diol of this embodiment, an ester exchange reaction catalyst is added. Examples of the catalyst include, but are not limited to, alcoholates, hydrides, oxides, amides, carbonates, hydroxides, nitrogen-containing borates, and basic alkali metal salts and alkaline earth metal salts of organic acids of alkali metals such as lithium, sodium, and potassium, and alkaline earth metals such as magnesium, calcium, strontium, and barium. Examples of the catalyst include, but are not limited to, metals, salts, alkoxides, and organic compounds of aluminum, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, gallium, germanium, zirconium, niobium, molybdenum, ruthenium, rhodium, palladium, silver, indium, tin, antimony, tungsten, rhenium, osmium, iridium, platinum, gold, thallium, lead, bismuth, and ytterbium. One or more catalysts can be selected and used from these. When one or more catalysts are used from among metals, salts, alkoxides, and organic compounds of sodium, potassium, magnesium, potassium, titanium, zirconium, tin, lead, and ytterbium, the polymerization of polycarbonate diol is favorable and there is little effect on the urethane reaction using the resulting polycarbonate diol, so this is preferred. It is even more preferred to use metals, salts, alkoxides, and organic compounds of titanium, ytterbium, tin, zirconium, and magnesium as the catalyst.

The polycarbonate diol of this embodiment can be produced by various methods described, for example, in Schnell, Polymer Reviews, Vol. 9, pp. 9-20 (1994).

A specific example of the method for producing the polycarbonate diol of this embodiment is shown below. The method for producing the polycarbonate diol of this embodiment is not particularly limited, but can be carried out, for example, in two stages. A dihydro compound and a carbonate compound are mixed in a molar ratio (dihydro compound:carbonate compound) of, for example, 20:1 to 1:10, and the first stage reaction is carried out at normal pressure or reduced pressure at 100 to 250°C. When dimethyl carbonate is used as the carbonate compound, the produced methanol can be removed as a mixture with dimethyl carbonate to obtain a low molecular weight polycarbonate diol. When diethyl carbonate is used as the carbonate compound, the produced ethanol can be removed as a mixture with diethyl carbonate to obtain a low molecular weight polycarbonate diol. Also, when ethylene carbonate is used as the carbonate compound, the produced ethylene glycol can be removed as a mixture with ethylene carbonate to obtain a low molecular weight polycarbonate diol. Next, in the second stage reaction, the reaction product from the first stage is heated under reduced pressure at 120 to 250°C to remove unreacted diol and carbonate, and the low molecular weight polycarbonate diol is condensed to obtain a polycarbonate diol of a specified molecular weight.

The number average molecular weight of the polycarbonate diol obtained by the manufacturing method of this embodiment is preferably 300 to 5000. If the number average molecular weight of the polycarbonate diol is 300 or more, the low temperature properties of the resulting polyurethane are good. If the number average molecular weight of the polycarbonate diol is 5000 or less, when it is used as a constituent material of a paint, there is no restriction on the paint solids concentration, and the moldability of the resulting polyurethane is not reduced, so this is preferable. The number average molecular weight of the polycarbonate diol is more preferably 450 to 3000.

Next, the present invention will be described with reference to examples and comparative examples.
The following examples are provided to illustrate the present invention and are not intended to limit the scope of the invention in any way.

The physical properties shown in the following examples and comparative examples were measured by the following methods.
1) Reaction rate of polycarbonate diol 75g of polycarbonate diol was placed in a 1L separable flask equipped with a stirrer, a cooling tube, and a thermometer. The polycarbonate diol was dried by heating and stirring at 80°C for 3 hours while reducing the pressure to about 2.5kPa. After confirming that the temperature of the polycarbonate diol in the flask was 80°C, diphenylmethane diisocyanate was added in an amount twice the molar amount of the aliphatic polycarbonate diol. After reacting at 80°C for 30 minutes, the reaction rate was measured from the reaction rate of the isocyanate.

2) Stability over time Polycarbonate diol was placed in a container, and the inside of the container was replaced with nitrogen, and then the container was sealed and left to stand in a thermostatic chamber at 50°C for 4 weeks. Thereafter, the reaction rate was measured by the method of 1) above, and the urethane reaction rate ratio was calculated using the following formula (1), which was used as an index of the stability of the inhibitory effect against the transesterification catalyst. It is assumed that 4 weeks at 50°C corresponds to about 3 years at room temperature (23°C). In addition, when the inhibitory effect against the ester catalyst does not change at all over time, the reaction rate ratio in formula (1) is 1. If the reaction rate ratio is 0.85 to 1.15, it is rare that the urethane reaction conditions need to be changed regardless of the storage time, and if it is 0.90 to 1.10, it is almost unnecessary to change the urethane reaction conditions. It is more preferable that the reaction rate ratio is 0.95 to 1.05.
Reaction rate ratio = B / A (1)
A: Reaction rate when using aliphatic polycarbonate diol before standing at 50°C for 4 weeks B: Reaction rate when using aliphatic polycarbonate diol after standing at 50°C for 4 weeks

3) Determination of Number Average Molecular Weight of Polycarbonate Diol The number average molecular weight of an aliphatic polycarbonate diol was calculated using the following formula (2) by determining the hydroxyl value (OH value) by the "neutralization titration method (JIS K0070-1992)" in which acetic anhydride and pyridine are used and titrated with an ethanol solution of potassium hydroxide.
Number average molecular weight = 2 / (OH value × 10-3 / 56.1) (2)

4) Analysis of contained elements (catalytic metal and phosphorus) by inductively coupled plasma (ICP) The elements contained in the aliphatic polycarbonate diol were analyzed as follows. First, the sample was weighed into a Teflon (registered trademark) decomposition container, and high-purity nitric acid (manufactured by Kanto Chemical) was added and decomposed using a microwave decomposition device (manufactured by Milestone General Co., Ltd., ETHOS TC). The sample was completely decomposed, and the decomposition liquid obtained was colorless and transparent. Pure water was added to the decomposition liquid to obtain a test liquid. The obtained test liquid was quantified using an inductively coupled plasma analyzer (manufactured by Thermo Fisher Scientific Co., Ltd., iCAP6300 Duo) based on the standard solution of each element.

[Preparation of Phosphate Ester Composition]
A phosphate ester composition was prepared in the proportions shown in Table 1 below.

[Example 1]
10.6 kg (90 mol) of 1,6-hexanediol and 7.9 kg (90 mol) of ethylene carbonate were charged into a 20 L reactor with a heating jacket, equipped with a rectification column with 10 theoretical plates packed with structured packing, a condenser, and a stirrer, and 1.6 g of titanium tetraisopropoxide was added as a catalyst. The reactor was depressurized to 1 kPa, nitrogen was introduced, and the pressure was returned to atmospheric pressure. This operation was repeated three times to replace the inside of the reactor with nitrogen.

Heating was started by passing a heat medium through the jacket, the pressure was adjusted to 7-8 kPa, and heating was continued for 3 hours at a reaction temperature of 160°C. No extraction was performed from the distillation column during this time.

Then, the reaction was continued for 15 hours while removing the mixture of ethylene glycol and ethylene carbonate produced. The reaction was continued for 5 hours without using a distillation column, at a pressure of 0.3 to 0.6 kPa and a reaction temperature of 160 to 175°C, while removing all of the distilled components. After returning to normal pressure, a solution of 1.5 g of phosphoric acid ester composition 1 added to 1.8 g of 2-ethylhexanol and stirred to make it uniform was added, and the mixture was stirred at 120°C for 3 hours while passing nitrogen through, to obtain an aliphatic polycarbonate diol (hereinafter abbreviated as PC-1) with a number average molecular weight of 1987 that is a white solid at room temperature.

[Examples 2 to 7]
Aliphatic polycarbonate diols (hereinafter, each of them is abbreviated as PC-2 to PC-7) were obtained by the method shown in Example 1, except that the phosphoric acid ester compositions shown in Table 2 were used and added in the amounts shown in Table 2. The amount of 2-ethylhexanol was adjusted so as to have the weight ratio to the phosphoric acid ester composition shown in Example 1.

[Comparative Examples 1 to 6]
Aliphatic polycarbonate diols (hereinafter, each of them is abbreviated as PC-21 to PC-26) were obtained by the method shown in Example 1, except that the phosphoric acid ester compositions shown in Table 2 were used and added in the amounts shown in Table 2. The amount of 2-ethylhexanol was adjusted so as to have the weight ratio to the phosphoric acid ester composition shown in Example 1.

[Example 8]
10.6 kg (90 mol) of 1,6-hexanediol and 7.9 kg (90 mol) of ethylene carbonate were charged into the apparatus used in Example 1, and 0.9 g of titanium tetrabutoxide was added as a catalyst. The reactor was reduced in pressure to 1 kPa, nitrogen was introduced, and the pressure was returned to atmospheric pressure. This operation was repeated three times to replace the inside of the reactor with nitrogen.

Heating was started by passing a heat medium through the jacket, the pressure was adjusted to 7-8 kPa, and heating was continued for 3 hours at a reaction temperature of 160°C. No extraction was performed from the distillation column during this time.

Then, the reaction was continued for 15 hours while removing the mixture of ethylene glycol and ethylene carbonate produced. The reaction was continued for 5 hours at a pressure of 0.3-0.6 kPa and a reaction temperature of 160-175°C without using a distillation column while removing all of the distilled components. After the pressure was returned to normal, a solution of 0.6 g of phosphoric acid ester composition 9 added to 0.7 g of 2-ethylhexanol and stirred to make it homogenous was added, and the mixture was stirred at 120°C for 3 hours while passing nitrogen through, to obtain an aliphatic polycarbonate diol (hereinafter abbreviated as PC-8).

[Example 9]
5.0 kg of 1,5-pentanediol, 5.5 kg of 1,6-hexanediol, and 8.3 kg of ethylene carbonate were charged into the apparatus used in Example 1, and 1.6 g of titanium tetraisopropoxide was added as a catalyst. The reactor was reduced in pressure to 1 kPa, nitrogen was introduced, and the pressure was returned to atmospheric pressure. This operation was repeated three times to replace the inside of the reactor with nitrogen.

Heating was started by passing a heat medium through the jacket, the pressure was adjusted to 7-8 kPa, and heating was continued for 3 hours at a reaction temperature of 160°C. No extraction was performed from the distillation column during this time.

Then, the reaction was continued for 15 hours while removing the mixture of ethylene glycol and ethylene carbonate produced. The reaction was continued for another 5 hours at a pressure of 0.3-0.6 kPa and a reaction temperature of 160-175°C without using a distillation column while removing all of the distilled components. After the pressure was returned to normal, a solution of 1.4 g of phosphoric acid ester composition 10 added to 1.7 g of 1-butanol and stirred to make it homogenous was added, and the mixture was stirred at 120°C for 3 hours while passing nitrogen through, to obtain an aliphatic polycarbonate diol (hereinafter abbreviated as PC-9).

[Example 10]
6.9 kg of 1,4-butanediol, 3.0 kg of 1,6-hexanediol, and 8.9 kg of ethylene carbonate were charged into the apparatus used in Example 1, and 1.8 g of titanium tetrabutoxide was added as a catalyst. The reactor was reduced in pressure to 1 kPa, nitrogen was introduced, and the pressure was returned to atmospheric pressure. This operation was repeated three times to replace the inside of the reactor with nitrogen.

Heating was started by passing a heat medium through the jacket, the pressure was adjusted to 7-8 kPa, and the reactor was heated at an internal temperature of 140°C for 3 hours. No discharge was made from the distillation column at this time.

Then, the reaction was continued for 15 hours while removing the mixture of ethylene glycol and ethylene carbonate produced. The reaction was continued for another 5 hours at a pressure of 0.3-0.6 kPa and a reaction temperature of 160-175°C without using a distillation column while removing all of the distilled components. After the pressure was returned to normal, 1.8 g of phosphoric acid ester composition 9 was added to a solvent mixture of 2.0 g of 2-ethylhexanol and 0.1 g of 1-butanol, which was stirred to make a homogenous solution, and the mixture was stirred at 120°C for 3 hours while passing nitrogen through, to obtain an aliphatic polycarbonate diol (hereinafter abbreviated as PC-10).

<Stability over time>
The stability over time of PC-1 to PC-5, PC-8 to PC-10, PC-21 to PC-23, and PC-26 was evaluated by the method of "2) Stability over time" above. The results are shown in Table 2.

<Reaction rate>
For PC-2, PC-6, PC-7, PC-24, and PC-25, the reaction rate was measured by the method of "1) Reaction rate of polycarbonate diol" above. If the effect of the transesterification catalyst on the urethane reaction is not reduced, the reaction rate of the isocyanate exceeds 45% in 10 minutes when the reaction rate is measured by the method of "1) Reaction rate of polycarbonate diol". (When all the hydroxyl groups of the polycarbonate react, the reaction rate of the isocyanate is 50%), making it difficult to control the urethane reaction. On the other hand, if the isocyanate reaction rate in 30 minutes is 8 to 20%, it is easy to control the urethane reaction, which is preferable. When PC-2 is used, the isocyanate reaction rate is in the above range, and the effect of the transesterification catalyst on the urethane reaction can be reduced. The results when the reaction rate of PC-2 is set to 1 are summarized in Table 2. The reaction rate is preferably 1.3 or less.

[Reference example 1]
In a separable flask, 110 g of aliphatic polycarbonate diol PC-1, 55 g of diphenylmethane-4,4-diisocyanate, 100 g of N,N-dimethylformamide, and 0.02 g of dibutyltin dilaurate as a catalyst were charged, and reacted at 80°C for 2 hours to obtain a urethane prepolymer. Then, 9.9 g of 1,4-butanediol and 308 g of N,N-dimethylformamide were dropped as chain extenders, and the reaction was continued for another 4 hours to obtain a polyurethane resin solution. The obtained polyurethane resin solution was cast on a glass plate, left at room temperature for 30 minutes to evaporate the solvent, and then dried in a 100°C dryer for 2 hours to obtain a polyurethane film.

[Reference example 2]
40 g of aliphatic polycarbonate diol PC-9, 0.75 g of BYK-331 (manufactured by BYK Chemicals) as a leveling agent, 1.25 g of dibutyltin dilaurate solution dissolved in thinner (xylene/butyl acetate = 70/30 (mass ratio)) to a concentration of 2 mass%, and 40 g of thinner were mixed and stirred to obtain a base paint. 7.5 g of organic polyisocyanate (Duranate TPA-100, manufactured by Asahi Kasei Chemicals, isocyanate (NCO) content: 23.1%) as a curing agent was added to the obtained base paint to prepare a coating composition application liquid.

The polycarbonate diol of the present invention is suitable as a raw material for polyurethanes, thermoplastic elastomers, urethane elastic fibers, etc.

Claims (6)

an aliphatic polycarbonate diol polymerized using a transesterification catalyst;
A phosphoric acid monoester represented by the following formula (a),
A phosphoric acid diester represented by the following formula (b),
A phosphate triester represented by the following formula (c),
mixing and heating;
Including,
the ratio of the number of moles of phosphorus to the number of moles of the transesterification catalyst is 0.1 to 5;
The mass ratio of the phosphoric acid monoester, the phosphoric acid diester, and the phosphoric acid triester is
50-90: 3-25: 0.01-5
(Phosphate monoester: Phosphate diester: Phosphate triester)
Satisfy the relationship
Method for producing aliphatic polycarbonate diol
[In the formula,
R ¹ is an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms,
^R2 's are each independently an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms;
Each ^R3 is independently an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms. The mixing step further comprises mixing phosphoric acid;
The mass ratio of the phosphoric acid monoester, the phosphoric acid diester, the phosphoric acid triester, and the phosphoric acid is
50-90: 3-25: 0.01-5: 3-25
(Phosphate monoester: Phosphate diester: Phosphate triester: Phosphate)
Satisfy the relationship
The method of claim 1 . In the mixing, the phosphoric acid monoester, the phosphoric acid diester, the phosphoric acid triester, and the phosphoric acid are dissolved in a solvent having an SP value of 8.0 to 11.0 (cal/cm ³ ) ^1/2 and mixed as such.
The method according to claim 2 . The heating is carried out at 70° C. to 170° C. for 15 minutes to 5 hours;
The method according to any one of claims 1 to 3. an aliphatic polycarbonate diol polymerized using a transesterification catalyst;
A phosphoric acid monoester represented by the following formula (a),
A phosphoric acid diester represented by the following formula (b),
A phosphate triester represented by the following formula (c),
Including,
the ratio of the number of moles of phosphorus to the number of moles of the transesterification catalyst is 0.1 to 5;
The mass ratio of the phosphoric acid monoester, the phosphoric acid diester, and the phosphoric acid triester is
50-90: 3-25: 0.01-5
(Phosphate monoester: Phosphate diester: Phosphate triester)
Satisfy the relationship
Aliphatic Polycarbonate Diol
[In the formula,
R ¹ is an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms,
^R2 's are each independently an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms;
Each ^R3 is independently an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms. Further comprising phosphoric acid,
The mass ratio of the phosphoric acid monoester, the phosphoric acid diester, the phosphoric acid triester, and the phosphoric acid is
50-90: 3-25: 0.01-5: 3-25
(Phosphate monoester: Phosphate diester: Phosphate triester: Phosphate)
Satisfy the relationship
The aliphatic polycarbonate diol according to claim 5 .