JP2009051887A - Polycarbonate diol whose reaction control is easy - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polycarbonate diol which is suitable as a raw material for polyurethanes, thermoplastic elastomers, and the like or as a constituting material for coatings, adhesives and the like. <P>SOLUTION: This polycarbonate diol comprising two kinds of specific repeating units and terminal hydroxyl groups is characterized by having a number-average mol.wt. of 300 to 20,000, a repeating unit ratio of 99:1 to 1:99, and a secondary terminal group index of 0.5 to 5.0%. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a polycarbonate diol suitable as a raw material for polyurethane, thermoplastic elastomer and the like, or as a constituent material for paint, adhesive and the like. More specifically, when producing polyurethane, thermoplastic elastomers, paints, adhesives, etc., this is a polycarbonate diol that can easily control the reaction, and has a good balance of performance such as hydrolysis resistance and heat resistance. Furthermore, the present invention relates to a polycarbonate diol capable of obtaining a polyurethane and a thermoplastic elastomer having further flexibility.

Polycarbonate diol is known as a material excellent in hydrolysis resistance, light resistance, oxidation degradation resistance, heat resistance and the like as a soft segment such as polyurethane and thermoplastic elastomer. However, polycarbonate diol using 1,6-hexanediol as a raw material has crystallinity and is difficult to handle because it is solid at room temperature, and polyurethane using this has the disadvantage of low flexibility and elastic recovery. Had. In order to solve these problems, an aliphatic copolycarbonate diol using 1,6-hexanediol and 1,5-pentanediol (see Patent Document 1) is disclosed.
On the other hand, when polycarbonate diol is used as a raw material for polyurethane, thermoplastic elastomer, urethane elastic fiber, or as a constituent material for paints, adhesives, etc., it reacts with a compound having a functional group that reacts with a hydroxyl group, such as isocyanate. used. Here, controlling the reaction between the compound having a functional group that reacts with a hydroxyl group and the polycarbonate diol is very important for stable production and stabilization of product quality.

Conventionally, polycarbonate diol tends to have a high molecular weight by the above-described reaction, and a high technique for controlling the reaction is required in order to obtain a target molecular weight. In addition, problems such as partial high molecular weight generation and generation of fine gels occurred, giving rise to problems in product quality. Furthermore, since the catalyst used in the production of polycarbonate diol affects the above reaction, the reaction control is made more difficult.
So far, various polycarbonate diols and methods for producing the same have been disclosed for the purpose of controlling the reaction rate in the above reaction. For example, a method of adjusting urethane reactivity by controlling the cooling rate of polycarbonate diol in a high temperature state after completion of the polymerization reaction (see Patent Document 2) is disclosed. This is intended to obtain a diol having a reaction rate according to the purpose without using an additive, but it has been difficult to control the cooling rate industrially. Moreover, the manufacturing method (refer patent document 3) of the reactive stabilized polycarbonate diol which makes the water | moisture content of the carbonate used as a raw material 15 ppm or less is disclosed. In addition to requiring a carbonate dehydration step, this method sometimes fails to provide a sufficient effect for stabilizing the reaction.

  As a method of deactivating the catalyst used for the production of polycarbonate diol so as not to affect the urethane reaction, etc., a method of inactivating the titanium-based catalyst by treating with water and further removing water (Patent Document) 4) and the like. Furthermore, a method for producing a polycarbonate diol containing a urethanization catalyst having a stable and high reactivity by heat-treating a polycarbonate diol containing a transesterification catalyst with a phosphorous acid triester is disclosed (see Patent Document 5). Yes. The above-described method aims to control the reaction rate in the reaction between the polycarbonate diol and a compound having a functional group that reacts with a hydroxyl group such as isocyanate. However, in the above method, particularly when the target molecular weight is in the reaction region where the molecular weight increases remarkably, it is extremely difficult to control the reaction to the target molecular weight, and there is a problem that a gel is formed. Further, if the reaction rate was further lowered in order to reduce it, the reaction time became extremely long and productivity became a problem.

  On the other hand, with respect to the polymer terminal hydroxyl group of the polycarbonate diol, there is a method for producing a polycarbonate diol in which the terminal of the polycarbonate diol is almost completely a hydroxyl group from dialkyl carbonate or diaryl carbonate and a polyhydroxy compound (see Patent Documents 6 and 7). It is disclosed. These methods solve the problem that when a polycarbonate diol is produced using dialkyl carbonate or diaryl carbonate as a carbonate raw material, the alkyl group or aryl group derived from the carbonate remains at the polymer terminal, and the polymer terminal is almost entirely hydroxyl grouped. The purpose is to produce a polycarbonate diol, and the description regarding the type of hydroxyl group at the polymer terminal and the control thereof also describes that the reaction between the polycarbonate diol and the compound having a functional group that reacts with the hydroxyl group is controlled. It has not been done.

A polycarbonate diol (see Patent Document 8) having a high primary terminal OH ratio is disclosed. However, when the primary terminal OH ratio is high, the reaction rate is often too fast, and it is difficult to control the reaction to the target molecular weight, particularly in the reaction region where the target molecular weight is significantly increased. There were problems such as gel formation. Further, a polycarbonate diol (see Patent Document 9) in which the ratio of the polymer terminal hydroxyl group is a specific value is disclosed. However, in the disclosed polymer terminal hydroxyl group ratio, high molecular weight polyurethane may not be polymerized, and further, the ratio of the polymer terminal hydroxyl group is only specified, and the hydroxyl group is primary or secondary. It has not been.
As shown above, the conventional technology has a good balance of performance such as hydrolysis resistance and heat resistance, and can obtain polyurethane and thermoplastic elastomers that are more flexible, and the reaction to produce them. There was no polycarbonate diol that could be properly controlled.

Japanese Patent Publication No. 5-29648 Japanese Patent No. 2623550 JP 2006-176704 A Japanese Patent Publication No. 8-26140 JP 2002-30143 Japanese Patent No. 2570300 Japanese Patent No. 3724561 Japanese Patent No. 3874664 JP 2006-104253 A

  An object of this invention is to provide the polycarbonate diol suitable as raw materials, such as a polyurethane and a thermoplastic elastomer, or as structural materials, such as a coating material and an adhesive agent. More specifically, when producing polyurethane, thermoplastic elastomers, paints, adhesives, etc., this is a polycarbonate diol that can easily control the reaction, and has a good balance of performance such as hydrolysis resistance and heat resistance. Another object of the present invention is to provide a polycarbonate diol capable of obtaining a polyurethane and a thermoplastic elastomer which are further rich in flexibility.

As a result of intensive studies to solve the above problems, the present inventor has obtained a secondary hydroxyl group in a polymer terminal hydroxyl group in a polycarbonate diol comprising a repeating unit represented by the following formulas (A) and (B) and a terminal hydroxyl group. It was found that the reactivity of the polycarbonate diol and the compound having a functional group capable of reacting with a hydroxyl group can be controlled by making the ratio of the specific range, and the present invention has been made.
That is, the present invention is a polycarbonate diol comprising a repeating unit represented by the following formulas (A) and (B) and a terminal hydroxyl group,

The number average molecular weight is 300 to 20000, the ratio of the repeating unit (A) to the repeating unit (B) is 99: 1 to 1:99 in molar ratio, and the secondary end group index is 0.5 to 5.0. %, Which provides a polycarbonate diol characterized by

  The present invention provides a polycarbonate diol that is most suitable as a raw material for polyurethane, thermoplastic elastomer, and the like, or as a constituent material for paints, adhesives, and the like. More specifically, there is almost no defect that an ultra-high molecular weight gel that is poorly soluble in a solvent that causes poor appearance such as coating is generated, and if the reaction rate is further lowered to reduce the gel formation, the target molecular weight is achieved. This is a polycarbonate diol that can control the reaction easily with almost no drawbacks of extremely long reaction time and low productivity, and a good balance of performance such as hydrolysis resistance and heat resistance. Furthermore, it has an effect of providing a polycarbonate diol that can obtain a polyurethane and a thermoplastic elastomer having more flexibility.

Hereinafter, the present invention will be specifically described.
When polycarbonate diol is used as a raw material for polyurethane, thermoplastic elastomer, urethane elastic fiber, or as a constituent material for paints, adhesives, etc., it reacts with a compound having a functional group that reacts with a hydroxyl group, such as isocyanate. Is done. The reactivity of these compounds with polycarbonate diol is very important.
Since the primary hydroxyl group is highly reactive, it becomes difficult to control the reaction depending on the type of isocyanate used in the reaction and the reaction conditions, and it cannot be adjusted to the target molecular weight, or a fine high molecular weight gel is formed. Such a problem occurred. Secondary hydroxyl group is less reactive with isocyanate than primary hydroxyl group, as shown in polyurethane stabilization / degradation countermeasures and new modification technology according to purpose (Technical Information Association, 2004, p325) Things are known. However, when the ratio of the secondary hydroxyl group in the polymer terminal hydroxyl group is increased, it takes a long time to obtain the target molecular weight, which causes a problem in productivity. Furthermore, when the reaction temperature was raised to shorten the reaction time, problems such as changes in physical properties of the product obtained by side reactions occurred.

In the present invention, in the polycarbonate diol composed of the repeating units represented by the above formulas (A) and (B) and the terminal hydroxyl group, the optimum value of the secondary hydroxyl group ratio in the polymer terminal hydroxyl group is found and causes almost the above problems. As a result, the reaction using the polycarbonate diol can be easily controlled.
The secondary end group index of the present invention is defined as follows. 70 g to 100 g of polycarbonate diol is heated and stirred at a temperature of 160 ° C. to 185 ° C. under a pressure of 0.1 kPa or less to obtain about 1 g of a fraction. This was subjected to gas chromatography analysis (hereinafter referred to as GC analysis), and the secondary end group index was calculated from the following formula (1) using the obtained peak area value. The GC analysis was performed using a gas chromatography 6890 (manufactured by Hewlett-Packard) with DB-WAX (manufactured by J & W) as a column and a hydrogen flame ionization detector (FID) as a detector. The temperature rising profile of the column was raised from 40 ° C. to 220 ° C. at 10 ° C./min and then held at that temperature for 15 minutes. Identification of each peak in the GC analysis was performed using the following GC-MS apparatus. The GC apparatus used 6890 (manufactured by Hewlett-Packard) with DB-WAX (manufactured by J & W) as a column, and the temperature was raised from an initial temperature of 40 ° C. to 220 ° C. at a heating rate of 10 ° C./min. As the MS apparatus, Auto-massSUN (manufactured by JEOL) was used at an ionization voltage of 70 eV, a scan range m / z = 10 to 500, and a photomultiplier gain of 450V.

Secondary end group index = B ÷ A × 100 (1)
A: Sum of GC area of diol
B: Sum of GC area of diol having at least one secondary hydroxyl group The above method is a method for analyzing a terminal compound desorbed from a polymer by condensing polycarbonate diol. When a polymer terminal is a hydroxyl group, it will remove | deviate from a polymer terminal as a diol (refer following formula (a)).

（式中、Ｒは炭化水素を表す。）

(In the formula, R represents a hydrocarbon.)

  On the other hand, when the polymer terminal is a secondary hydroxyl group, a diol having at least one secondary hydroxyl group is removed from the polymer terminal. (See formula (b) below).

（式中、 Ｒ、Ｒ_１、Ｒ_２は炭化水素を表す。）

(In the formula, R, R ₁ and R ₂ represent hydrocarbons.)

Therefore, the ratio of the secondary hydroxyl group in the polymer terminal hydroxyl group can be determined by the total amount of the diol in which at least one hydroxyl group is secondary to the amount of diol to be distilled.
When the secondary end group index is 0.5 to 5.0, when used as a raw material such as polyurethane or thermoplastic elastomer or with a constituent material such as paint or adhesive, the control of the reaction becomes easy and fine. The desired molecular weight can be obtained without producing a high molecular weight gel. When the secondary end group index is less than 0.5, it becomes difficult to control the reaction depending on the type of isocyanate used for the reaction and the reaction conditions. When the secondary terminal group index exceeds 5.0, the reaction rate becomes slow, and it often takes a long time to reach the target molecular weight, resulting in a decrease in productivity. When the secondary end group index is from 0.7 to 4.0, the above problem is less likely to occur, and the control of the reaction is further facilitated. When the secondary end group index is 1.0 to 3.0, the above problem hardly occurs and it is more preferable.

The method for producing the polycarbonate diol of the present invention is not particularly limited. For example, it can be produced by various methods described in Schnell, Polymer Reviews, Vol. 9, p9-20 (1994).
The polycarbonate diol of the present invention uses diol and carbonate as raw materials, but its purity is important. The polycarbonate diol of the present invention may not be obtained depending on the content of impurities such as a diol having a secondary hydroxyl group or a polycarbonate diol to be obtained such as a monoalcohol, the terminal of which is a non-reactive group such as an alkyl group. Therefore, the purity of the raw material used is preferably higher, and is usually 95% by weight or more, preferably 97% by weight or more, and more preferably 98% by weight or more.

  In order to obtain the polycarbonate diol having the secondary end group index of the present invention, for example, the content of diol having a secondary hydroxyl group contained in 1,5-pentanediol or 1,6-hexanediol as a raw material is controlled. There is a way. There is also a method of adding a diol having a secondary hydroxyl group as required. The diol having a secondary hydroxyl group can be added to the raw material, added during the production of the polycarbonate diol, or added after reaching a predetermined molecular weight. When adding to the raw material or in the middle of the reaction, there is no need to change the polymerization conditions of the polycarbonate diol, but the diol and carbonate composition ratio, catalyst amount, reaction temperature, reaction time, etc. may be changed as necessary. Also good. In the method in which a diol having a secondary hydroxyl group is added to the obtained polycarbonate diol and subjected to heat treatment, the heat treatment temperature is 120 ° C to 190 ° C, preferably 130 ° C to 180 ° C. When the heating temperature is lower than 120 ° C., the reaction is slow and processing time is required, which is economically problematic. The heat treatment time varies depending on the reaction temperature and the treatment method, but is usually 15 minutes to 10 hours. Examples of diols having secondary hydroxyl groups include 1,2-propanediol, 1,3-butanediol, 1,2-pentanediol, 1,4-pentanediol, 1,2-hexanediol, and 1,5-hexanediol. Having primary and secondary hydroxyl groups such as 2-ethyl-1,3-hexanediol, 1,2-octanediol, 1,2-decanediol, 1,2-cyclopentanediol, 1,3-cyclo Two secondary compounds such as pentanediol, 1,3-cyclohexanediol, 1,4-cyclohexanediol, 2,3-butanediol, 2,4-pentanediol, 2,5-hexanediol, 3,5-heptanediol, etc. Those having a hydroxyl group, those having one secondary hydroxyl group and one tertiary hydroxyl group such as 2-methyl-2,4-pentanediol It is. These diols are used alone or in combination of two or more. In selecting a diol having a secondary hydroxyl group, the reactivity of the secondary hydroxyl group is important in addition to having a small effect on the polymerization reaction of the polycarbonate diol. The distance between the primary hydroxyl group and the secondary hydroxyl group is preferably large, and it is preferable that the steric hindrance to the secondary hydroxyl group is small. The reactivity of the secondary hydroxyl group is greatly influenced by steric hindrance to the secondary hydroxyl group. For example, when X in the following formula (c) is an alkyl group, the reactivity of the secondary hydroxyl group is greatly inhibited as the methylene chain length increases. If the alkyl group is a methyl group or an ethyl group, the steric hindrance to the secondary hydroxyl group is small and preferable. Furthermore, a methyl group is more preferable as the diol having a secondary hydroxyl group of the present invention. In the case of a hydroxyl group bonded to a cyclohexyl ring, it is preferable that the mutual hydroxyl group is in the ortho position.

HO-R-CH (OH) -X (c)
From the above viewpoint, 1,5-hexanediol or 1,4-cyclohexanediol is preferable as the diol having a secondary hydroxyl group. The proportion of 1,5-hexanediol and / or 1,4-cyclohexanediol in the diol having a secondary hydroxyl group (hereinafter referred to as 1,5HD / 1,4CHD index) is the above-mentioned secondary end group index. Analysis is performed by the method shown in the definition of, and using the result, the following equation (2) is obtained. In the present invention, the 1,5HD / 1,4CHD index is preferably 50% or more. Further, it is more preferably 85% or more.

1,5HD / 1,4CHD index = C / B × 100 (2)
B: Sum of GC areas of diols having at least one secondary hydroxyl group C: Sum of GC areas of 1,5-hexanediol and / or 1,4-cyclohexanediol Polymer ends are hydroxyl groups such as alkyl groups and aryl groups. In the case of a group that does not react, when the polyurethane is polymerized using the polycarbonate diol, the desired molecular weight is often not obtained, and many low molecular weight substances are present, so that the mechanical properties of the obtained polyurethane may be lowered. It was. The polycarbonate diol of the present invention preferably has a hydroxyl group at the polymer end. For example, the analysis is performed by the method shown in the definition of the secondary terminal group index, and the terminal hydroxyl index determined by the following formula (3) using the result is preferably 97.0 or more.
Furthermore, it is more preferable that the terminal hydroxyl index is 98.5 to 99.8.

Terminal hydroxyl index = A ÷ D × 100 (3)
A: Sum of GC area of diol
D: Sum of GC area of monoalcohol and diol In the method shown in the definition of the secondary terminal group index, when the polymer terminal is not a hydroxyl group, it is removed from the polymer terminal as a monoalcohol (see the following formula (d)).

（式中、Ｒは上記と同じであり、Ｘは特に限定しないが、水酸基以外であり水素または炭化水素を表す。）

(In the formula, R is the same as above, and X is not particularly limited, but is other than a hydroxyl group and represents hydrogen or hydrocarbon.)

Therefore, the ratio of the polymer terminal which is a hydroxyl group can be determined from the amount of diol and monoalcohol in the fraction.

  In the polycarbonate diol of the present invention, 1,5-pentanediol and 1,6-hexanediol are used as the diol. Furthermore, ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-, as long as the properties of the polycarbonate diol of the present invention are not impaired. Non-side diols such as nanodiol, 1,10-dodecanediol, 1,11-undecanediol, 1,12-dodecanediol, 2-methyl-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, Side chains such as 2-butyl-2-ethyl-1,3-propanediol and 2,2-dimethyl-1,3-propanediol With diols, 1,4-cyclohexanedimethanol, 2-bis (4-hydroxycyclohexyl) - cyclic diols such as propane, may be added to one or more kinds of diol as a raw material. The addition amount is 0.1 to 10% by weight, preferably 0.1 to 3% by weight, based on the total amount of 1,5-pentanediol and 1,6-hexanediol. A small amount of a compound having three or more hydroxyl groups per molecule, for example, trimethylolethane, trimethylolpropane, hexanetriol, pentaerythritol and the like can be used. When too many compounds having three or more hydroxyl groups in one molecule are used, gelation occurs due to crosslinking during the polymerization reaction of the polycarbonate. Therefore, the compound having 3 or more hydroxyl groups in one molecule is preferably 0.1 to 5% by weight based on the total amount of 1,5-pentanediol and 1,6-hexanediol. More preferably, it is 0.1 to 2% by weight.

  The polycarbonate diol of the present invention includes, as carbonates, dialkyl carbonates such as dimethyl carbonate, diethyl carbonate, dipropyl carbonate, and dibutyl carbonate, diaryl carbonates such as diphenyl carbonate, ethylene carbonate, trimethylene carbonate, 1,2-propylene carbonate, 1, Examples thereof include alkylene carbonates such as 2-butylene carbonate, 1,3-butylene carbonate, and 1,2-pentylene carbonate. From the viewpoint of easy availability and ease of setting conditions for the polymerization reaction, it is preferable to use dimethyl carbonate, diethyl carbonate, diphenyl carbonate, or ethylene carbonate.

  In the production of the polycarbonate diol of the present invention, a catalyst may or may not be added. When adding a catalyst, it can select freely from a normal transesterification catalyst. For example, lithium, sodium, potassium, rubidium, cesium, magnesium, calcium, strontium, barium, zinc, aluminum, titanium, cobalt, germanium, tin, lead, antimony, arsenic, cerium and other metals, salts, alkoxides, organic compounds Used. Particularly preferred are titanium, tin and lead compounds. Moreover, the usage-amount of a catalyst is 0.00001 to 0.1% of polycarbonate diol weight normally.

Ratio of repeating units derived from 1,5-pentanediol (formula (A)) and repeating units derived from 1,6-hexanediol (formula (B)) in the molecule (hereinafter referred to as copolymerization ratio). The above formula (A): represented by the above formula (B)) is 99: 1 to 1:99 in molar ratio. A copolymerization ratio of 75:25 to 25:75 is preferable because flexibility is improved. When it is 70:30 to 30:70, flexibility appears most remarkably.
The copolymerization ratio in the present invention was determined by the following method. 1 g of a sample is taken into a 100 ml eggplant flask, 30 g of ethanol and 4 g of potassium hydroxide are added, and reacted at 100 ° C. for 1 hour. After cooling to room temperature, add 2-3 drops of phenolphthalein to the indicator and neutralize with hydrochloric acid. After cooling in the refrigerator for 1 hour, the precipitated salt was removed by filtration, and 1,5-pentanediol and 1,6-hexanediol were quantified using GC. GC analysis was performed using gas chromatography GC-14B (manufactured by Shimadzu Corporation) with DB-WAX (manufactured by J & W) as a column, diethylene glycol diethyl ester as an internal standard, and a detector as FID. The temperature rising profile of the column was maintained at 60 ° C. for 5 minutes and then heated to 250 ° C. at 10 ° C./min. The copolymerization ratio is represented by a molar ratio of 1,5-pentanediol and 1,6-hexanediol.

In the polycarbonate diol of the present invention, the molecular weight is 300 to 20000 in terms of number average molecular weight. When the number average molecular weight is less than 300, the flexibility and low temperature characteristics of the obtained thermoplastic polyurethane are often poor, and when it exceeds 20000, the molding processability of the obtained thermoplastic polyurethane is often lowered, which is not preferable. The number average molecular weight is preferably in the range of 450 to 5000. More preferably, it is 500-3000.
The number average molecular weight of the present invention is determined by determining the hydroxyl value by “neutralization titration method (JIS K 0070-1992)” in which acetic anhydride and pyridine are used and titrated with an ethanol solution of potassium hydroxide. Used to calculate.
Number average molecular weight = 2 / (OH value × 10 ⁻³ /56.1) (4)

  The polycarbonate diol used by 1,5-pentanediol and 1,6-hexanediol as the diol has a good balance of performance such as hydrolysis resistance and heat resistance and is liquid at room temperature due to its low crystallinity. Compared with polycarbonate diol using only 1,6-hexanediol, it is possible to obtain polyurethane and thermoplastic elastomer having excellent flexibility and elastic recovery. In addition to the above characteristics, the polycarbonate diol of the present invention also has a characteristic that its reaction can be easily controlled in the production of urethane and the like, and is used as a raw material for polyurethanes, thermoplastic elastomers, etc., or paints and adhesives. It can be said that the polycarbonate diol is suitable as a constituent material.

Next, the present invention will be described with reference to examples and comparative examples.
1. Evaluation of Reactivity In the present invention, the reaction stability of polycarbonate diol was evaluated by the following method. 75 g of polycarbonate diol was placed in a 1 L separable flask equipped with a stirrer, a condenser, and a thermometer. While reducing the pressure at about 2.5 kPa, the mixture was heated and stirred at 100 ° C. for 3 hours to dry the polycarbonate diol. After adding 25 g of toluene and 0.006 g of dibutyltin dilaurate, confirm that the inside of the flask is at 80 ° C., add 2 times the molar amount of disoylhexylmethane diisocyanate of polycarbonate diol, and at 80 ° C. React for 3 hours to obtain a prepolymer. After adding 350 ml of dimethylformamide, the reaction rate of the isocyanate is measured. After cooling to 30 ° C., ethylenediamine corresponding to 90% of the amount required for the isocyanate reaction rate to be 100% from the measured isocyanate reaction rate is added to carry out chain extension reaction. After stirring for 10 minutes, a sample (hereinafter referred to as sample A) is collected. Thereafter, ethylenediamine corresponding to 40% of the amount required for the isocyanate reaction rate to be 90% to 100% is added, and the chain extension reaction is continued. After stirring for 3 minutes, a sample (hereinafter referred to as sample B) is collected. Further, the sample is stirred for 7 minutes (hereinafter referred to as sample C) and collected. Put the sample in a transparent sample bottle and visually check the properties and the presence or absence of gels. Using a viscometer (B8L, manufactured by TOKIMEC) The viscosity was measured. Based on the measured values, the A value and the B value represented by the following formulas (5) and (6) were determined, and the reactivity was evaluated.
A value = (viscosity of sample B) / (viscosity of sample A) (5)
B value = (viscosity of sample C) / (viscosity of sample B) (6)

2. Analysis of raw diol 1,5-hexanediol and 1,6-hexanediol used as diol raw materials were analyzed by gas chromatography. The conditions were gas chromatography GC-14B (manufactured by Shimadzu Corporation) with DB-WAX (manufactured by J & W) as a column, diethylene glycol diethyl ester as an internal standard, and a detector as FID. The temperature rising profile of the column was maintained at 60 ° C. for 5 minutes and then heated to 250 ° C. at 10 ° C./min. A diol having a secondary hydroxyl group in which 1,5-hexanediol is 1.2% by weight in 1,5-pentanediol and 1,4-cyclohexanediol is 0.6% by weight in 1,6-hexanediol. Was identified as an impurity. Monoalcohol was not detected as an impurity in 1,6-hexanediol and 1,4-cyclohexanediol monoalcohol.

[Example 1]
In a 2 L glass flask equipped with a rectification column packed with a regular packing and a stirrer, 504 g (5.6 mol) of dimethyl carbonate, 312 g (3.0 mol) of 1,5-pentanediol, 1,6-hexane The diol was charged in 307 g (2.6 mol). As a diol having a secondary hydroxyl group, 1.8 g of 1,4-cyclohexanediol, 2.8 g of 1,5-hexadiol and 0.085 g of titanium tetrabutoxide as a catalyst were added, and the mixture was stirred and heated at normal pressure. While gradually increasing the reaction temperature from 150 ° C. to 210 ° C., the reaction was carried out for 5 hours while distilling off the resulting mixture of methanol and dimethyl carbonate. Thereafter, the pressure was reduced to 15 kPa, and the mixture was further reacted at 210 ° C. for 5 hours while distilling off a mixture of methanol and dimethyl carbonate. When the obtained polycarbonate diol was analyzed, the number average molecular weight was 1854, the copolymerization ratio was 1,5-pentanediol: 1,6-hexanediol = 53: 47, and the secondary end group index was 2.3. It was. Further, the terminal hydroxyl group index was 98.8.

[Comparative Example 1]
Polymerization was carried out by the method shown in Example 1 except that the amount of diol having a secondary hydroxyl group was 13.2 g of 1,5-hexanediol and 5.3 g of 1,4-cyclohexanediol. When the obtained polycarbonate diol was analyzed, the number average molecular weight was 1862, the copolymerization ratio was 1,5-pentanediol: 1,6-hexanediol = 53: 47, and the secondary end group index was 5.2. Met. Moreover, the terminal hydroxyl index was 98.6.

[Example 2]
Polymerization was carried out under the conditions shown in Example 1, and the reaction was conducted while distilling off a mixture of methanol and dimethyl carbonate for 5 hours. When the obtained polycarbonate diol was analyzed, the number average molecular weight was 2890, the copolymerization ratio was 52:48, and the secondary end group index was 2.5. The terminal hydroxyl index was 97.8.

[Example 3]
Polymerization was carried out using the apparatus shown in Example 1. 720 g (6.1 mol) of diethyl carbonate, 225 g (2.2 mol) of 1,5-pentanediol, and 370 g (3.1 mol) of 1,6-hexanediol were charged. As a diol having a secondary hydroxyl group, 2.2 g of 1,4-cyclohexanediol and 2.0 g of 1,5-hexadiol were added, and 0.10 g of titanium tetrabutoxide was added as a catalyst, followed by stirring and heating at normal pressure. While gradually raising the reaction temperature from 150 ° C. to 200 ° C., the reaction was carried out for 3 hours while distilling off the resulting mixture of ethanol and diethyl carbonate. Thereafter, the pressure was reduced to 15 kPa, and the mixture was further reacted at 200 ° C. for 4 hours while distilling off a mixture of ethanol and diethyl carbonate. When the obtained polycarbonate diol was analyzed, the number average molecular weight was 1042, and the copolymerization ratio was 1,5-pentanediol: 1,6-hexanediol = 41: 59, secondary end group index was 1.9. Met. The terminal hydroxyl group index was 97.4.

[Comparative Example 2]
Polymerization was carried out using the apparatus shown in Example 1. 750 g (6.4 mol) of diethyl carbonate, 225 g (2.2 mol) of 1,5-pentanediol, and 370 g (3.1 mol) of 1,6-hexanediol were charged. After adding 17.2 g of 1,4-cyclohexanediol and 7.0 g of 1,5-hexadiol as a diol having a secondary hydroxyl group and 0.10 g of titanium tetrabutoxide as a catalyst, the reaction was conducted under the conditions of Example 3. Went. When the obtained polycarbonate diol was analyzed, the number average molecular weight was 953, the copolymerization ratio was 1,5-pentanediol: 1,6-hexanediol = 41: 59, and the secondary end group index was 5.5. Met. Further, the terminal hydroxyl group index was 96.4.

[Example 4]
Polymerization was carried out using the apparatus shown in Example 1. 720 g (6.1 mol) of diethyl carbonate, 225 g (2.2 mol) of 1,5-pentanediol, and 370 g (3.1 mol) of 1,6-hexanediol were charged. 0.10 g of titanium tetrabutoxide was added as a catalyst, and the mixture was stirred and heated at normal pressure. While gradually raising the reaction temperature from 150 ° C. to 200 ° C., the reaction was carried out for 7 hours while distilling off the resulting mixture of ethal and diethyl carbonate. Thereafter, the pressure was reduced to 15 kPa, and the mixture was further reacted at 200 ° C. for 4 hours while distilling off a mixture of ethanol and diethyl carbonate. When the obtained polycarbonate diol was analyzed, the number average molecular weight was 1920, and the copolymerization ratio was 1,5-pentanediol: 1,6-hexanediol = 40: 60, and the secondary end group index was 1.4. Met. The terminal hydroxyl index was 97.7.

[Example 5]
700 g (8.0 mol) of ethylene carbonate, 420 g (4.0 mol) of 1,5-pentanediol, 1,6-hexane in a 2 L glass flask equipped with a rectification column packed with a regular packing and a stirrer Diol 470 g (4.0 mol) was charged. As a catalyst, 0.18 g of titanium tetrabutoxide was added and stirred and heated at normal pressure. While gradually raising the reaction temperature from 150 ° C. to 180 ° C., the reaction was carried out for 18 hours while distilling off the mixture of ethylene glycol and ethylene carbonate to be produced. Thereafter, the pressure was reduced to 15 kPa, and the reaction was further carried out at 180 ° C. for 10 hours while distilling off the diol and ethylene carbonate. When the obtained polycarbonate diol was analyzed, the number average molecular weight was 2058, and the copolymerization ratio was 1,5-pentanediol: 1,6-hexanediol = 49: 51, secondary end group index was 1.3. Met. Further, the terminal hydroxyl group index was 99.4.

[Example 6]
0.44 g of 1,4-cyclohexanediol as a diol having a secondary hydroxyl group was added to 300 g of the polycarbonate diol obtained in Example 5, and the mixture was stirred at 150 ° C. for 7 hours at normal pressure. When the obtained polycarbonate diol was analyzed, the number average molecular weight was 2008, and the copolymerization ratio was 1,5-pentanediol: 1,6-hexanediol = 49: 51, the secondary end group index was 2.1. Met. Moreover, the terminal hydroxyl index was 99.3.
The starting diol was purified by distillation. As a result of analyzing raw material diol by GC, 1,5-hexanediol was found to be an impurity of diol having a secondary hydroxyl group in 1,5-pentanediol. In 7% by weight of 1,6-hexanediol, 0.4% by weight of 1,4-cyclohexanediol was confirmed. Thereafter, in Comparative Examples 3, 4 and Example 7, a diol obtained by distillation purification was used as a raw material.

[Comparative Example 3]
620 g (7.0 mol) of ethylene carbonate, 208 g (2.0 mol) of 1,5-pentanediol, 1,6-hexane in a 2 L glass flask equipped with a rectification column packed with a regular packing and a stirrer 590 g (5.0 mol) of diol was charged. 0.020 g of lead acetate trihydrate was added as a catalyst, and the mixture was stirred and heated at normal pressure. While gradually increasing the reaction temperature from 150 ° C. to 175 ° C., the reaction was carried out for 15 minutes while distilling off the mixture of ethylene glycol and ethylene carbonate to be produced. Thereafter, the pressure was reduced to 15 kPa, and the reaction was further performed at 175 ° C. for 10 hours while distilling off the diol and ethylene carbonate. When the obtained polycarbonate diol was analyzed, the number average molecular weight was 795, and the copolymerization ratio was 1,5-pentanediol: 1,6-hexanediol = 29: 71, secondary end group index was 0.4. Met. Moreover, the terminal hydroxyl index was 99.8.

[Example 7]
Polymerization was carried out by the method shown in Comparative Example 4 except that 1,4-cyclohexanediol was added to the 9.3 g raw material as a diol having a secondary hydroxyl group. When the obtained polycarbonate diol was analyzed, the number average molecular weight was 784, the copolymerization ratio was 1,5-pentanediol: 1,6-hexanediol = 28: 72, and the secondary end group index was 1.8. Met. The terminal hydroxyl index was 99.7.

[Comparative Example 4]
Polymerization was carried out using the apparatus shown in Example 1. 503 g (5.6 mol) of dimethyl carbonate, 310 g (3.0 mol) of 1,5-pentanediol, and 308 g (2.6 mol) of 1,6-hexanediol were charged. As a diol having a secondary hydroxyl group, 1.8 g of 1,4-cyclohexanediol, 2.8 g of 1,5-hexadiol and 0.085 g of titanium tetrabutoxide as a catalyst were added, and the mixture was stirred and heated at normal pressure. While gradually increasing the reaction temperature from 150 ° C. to 210 ° C., the reaction was carried out for 5 hours while distilling off the resulting mixture of methanol and dimethyl carbonate. Thereafter, the pressure was reduced to 15 kPa, and the mixture was further reacted at 210 ° C. for 5 hours while distilling off a mixture of methanol and dimethyl carbonate. When the obtained polycarbonate diol was analyzed, the number average molecular weight was 1866, and the copolymerization ratio was 1,5-pentanediol: 1,6-hexanediol = 52: 48, secondary end group index was 0.3. It was. Moreover, the terminal hydroxyl index was 98.6.
Table 1 below shows the results of reactivity evaluation and visual inspection of the polycarbonate diols of the above Examples and Comparative Examples.

−：粘度測定可能 微細ゲルの生成など特記事項がない

-: Viscosity can be measured.

  It can be used as a raw material such as polyurethane and thermoplastic elastomer having excellent balance of physical properties such as hydrolysis resistance, heat resistance and flexibility, or as a constituent material such as paint and adhesive.

Claims (1)

A polycarbonate diol comprising a repeating unit represented by the following formulas (A) and (B) and a terminal hydroxyl group,

The number average molecular weight is 300 to 20000, the ratio of the repeating unit (A) to the repeating unit (B) is 99: 1 to 1:99 in molar ratio, and the secondary end group index is 0.5 to 5.0. A polycarbonate diol characterized by