JP3395383B2 - Polyester polyol and method for producing the same - Google Patents

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to polyester polyols. More specifically, the present invention relates to a polycaprolactone-based polyester polyol having a low melting point, excellent workability when used in various applications such as paints, and excellent in curing characteristics, and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, polycaprolactone-based polyester polyols are easy to control the hydroxyl value and the molecular weight during production, and also have flexibility, water resistance, low temperature characteristics,
Since it has excellent weather resistance and the like, it has been used as a raw material for producing polyurethane in many fields such as foams, adhesives, elastomers and paints along with polyether polyols such as polypropylene glycol. Further, the polycaprolactone-based polyester polyol is used for producing an adhesive, a coating agent, etc., in addition to the use as a raw material for producing polyurethane, in combination with various curing agents having reactivity with the hydroxyl group, such as melamine resin and epoxy resin. It is used to

Conventionally, as a polycaprolactone-based polyester polyol, a polyester polyol having a terminal hydroxyl group obtained by subjecting a dihydric or trihydric polyhydric alcohol as a raw material to ring-opening polymerization of caprolactone is known. Although this type of polyester polyol is excellent in heat resistance, mechanical properties, and water resistance, it has a drawback of having a high melting point (40 to 60 ° C.). That is, conventionally known polyester polyol of this kind,
Usually, since it is a waxy solid at room temperature, it must be melted before using it, which causes a problem of extremely poor workability.

As a solution to the above problem, a polyhydric alcohol having a side chain and a polybasic acid or an anhydride thereof are subjected to a dehydration esterification reaction to obtain a polyester polyol, and then the obtained polyester polyol and ε-caprolactone are esterified. There has been proposed a method for producing a polycaprolactone-based polyester polyol which is liquid at room temperature or has a melting point close to room temperature, which undergoes an exchange reaction (for example, JP-B-3-5
7133). However, since the polyester polyol obtained by this method has a small number of functional groups, it requires a high temperature and a long time to cure a composition using the same, and thus the workability of coating work etc. However, it has another drawback that the work efficiency is extremely poor, and cannot be a fundamental solution.

As another solution to the above problem, a hydroxyl group-containing polyester is produced by reacting an aliphatic polyol (polyhydric alcohol) having 3 or 4 or more hydroxyl groups per molecule with a dicarboxylic acid or an acid anhydride, next,
This polyester is 1 by weight of the resulting polyester
A method for producing a modified polyester by reacting with ε-caprolactone in an amount corresponding to 0 to 60% (for example, JP-A-50-1
35197) has also been proposed. However, in this production method, since the number of functional groups of the polyhydric alcohol used for producing the hydroxyl group-containing polyester is large, there is a big problem that gelation or insolubilization occurs during the esterification reaction.

[0006]

SUMMARY OF THE INVENTION The present invention is intended to solve the above-mentioned conventional technical problems and has a low melting point and good workability when used for various applications such as paints. It is an object of the present invention to provide a polycaprolactone-based polyester polyol having excellent curing properties and a method for producing the same.

[0007]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventors have found that a specific polyester having a hydroxyl group at the end and a polyfunctional alcohol having 3 to 15 carbon atoms and having a valence of 3 or more. In addition, by the ring-opening polymerization of ε-caprolactone, and further by a low melting point polycaprolactone-based polyester polyol obtained by subjecting the ring-opening polymerization product to a transesterification reaction, it was found that the above problems can be solved, and the present invention has been completed. Is.

In order to solve the above-mentioned problems, in the polyester polyol according to claim 1, the polyhydric alcohol having a carbon number of 2 to 10 and / or a trihydric alcohol is reacted with a polybasic acid or an acid anhydride thereof. Obtained with a molecular weight of 20
A ring-opening polymerization of ε-caprolactone (C) is carried out on a polyester (A) having a hydroxyl group at the terminal in the range of 0 to 5000 and a polyfunctional alcohol (B) having 3 to 15 carbon atoms and having a valence of 3 or more. Obtained by subjecting ring-opening polymerization products to transesterification reaction with each other, and having a number average molecular weight of 1,000 to 1
Measures are taken to make the range 0000. In the polyester polyol according to claim 2, the polyfunctional alcohol (B) according to claim 1 has ε-.
It is obtained by subjecting caprolactone (C) to ring-opening polymerization, and subjecting this ring-opening polymerization product (Bc) to the polyester (A) according to claim 1 for transesterification, and having a number average molecular weight of 10
The means for setting the range of 00 to 10,000 is taken. Furthermore, in the polyester polyol according to claim 3, the polyester (A) according to claim 1
Is obtained by subjecting ε-caprolactone (C) to ring-opening polymerization, and subjecting this ring-opening polymerization product (Ac) to a transesterification reaction with the polyfunctional alcohol (B) according to claim 1, and having a number average molecular weight of 1,000 to The means for setting the range to 10,000 is taken. Furthermore, in the polyester polyol according to claim 4, a ring-opening polymerization product (Ac) obtained by subjecting the polyester (A) according to claim 1 to ring-opening polymerization of ε-caprolactone (C), and the polyester polyol according to claim 1. A polyfunctional alcohol (B) is obtained by subjecting a ring-opening polymerization product (Bc) obtained by ring-opening polymerization of ε-caprolactone (C) to a transesterification reaction, and having a number average molecular weight of 1,000 to 1,000.
This means that the range is set to 0.

In the method for producing a polyester polyol according to claim 8, the molecular weight is obtained by reacting a divalent and / or trivalent polyhydric alcohol having 2 to 10 carbon atoms with a polybasic acid or an acid anhydride thereof. Is in the range of 200 to 5000, and ε-caprolactone (C) is subjected to ring-opening polymerization in a mixture of a polyester (A) having a hydroxyl group at the terminal and a polyfunctional alcohol (B) having 3 to 15 carbon atoms and having a valence of 3 or more. Further, a means of transesterifying the obtained ring-opening polymerization products is taken. Further, in the method for producing a polyester polyol according to claim 9, a ring-opening polymerization product (Bc) obtained by subjecting the polyfunctional alcohol (B) according to claim 8 to ring-opening polymerization of ε-caprolactone (C). And the polyester (A) described in claim 8 is transesterified. Furthermore, in the method for producing a polyester polyol according to claim 10, a ring-opening polymerization product (Ac) obtained by subjecting the polyester (A) according to claim 8 to ring-opening polymerization of ε-caprolactone (C), The means for transesterifying the polyfunctional alcohol (B) according to claim 8 is taken. Furthermore, in the method for producing a polyester polyol according to claim 11, a ring-opening polymerization product (Ac) obtained by subjecting the polyester (A) according to claim 8 to ring-opening polymerization of ε-caprolactone (C). The polyfunctional alcohol (B) according to claim 8.
In this method, the ring-opening polymerization product (Bc) obtained by ring-opening polymerization of ε-caprolactone (C) is transesterified.

The present invention will be described in detail below. The first raw material component of each polyester polyol of the present invention is a polyester (A) having a hydroxyl group at the terminal. This polyester (A) is obtained by reacting a divalent and / or trivalent polyhydric alcohol having 2 to 10 carbon atoms with a polybasic acid or an acid anhydride thereof, and has a molecular weight of 200 to 5000. is there.

The polyhydric alcohol used for obtaining the polyester (A) is not particularly limited as long as it is a divalent or trivalent alcohol having 2 to 10 carbon atoms. Specific examples thereof include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, 1,2.
-Butanediol, 1,3-butanediol, 1,4-
Butanediol, 2,3-butanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, neopentyl glycol, 2-methyl-1,3-propanediol, 2-methyl-2-propyl -1,3-
Propanediol, 2-butyl-2-ethyl-1,3-
Propanediol, 1,6-hexanediol, 2-methyl-2,4-pentanediol, 2,2,4-trimethyl-1,3-pentanediol, 2-ethyl-1,3
-Hexanediol, 2,5-dimethyl-2,5-hexanediol, 1,8-octanediol, 2-methyl-1,8-octanediol, 1,9-nonanediol and other aliphatic glycols, bishydroxymethyl Alicyclic glycol such as cyclohexane, xylylene glycol,
A glycol having an aromatic ring such as bishydroxyethoxybenzene, glycerin, trimethylolpropane, trimethylolethane, 1,2,6-hexanetriol,
Examples thereof include 1,2,4-butanetriol, but are not limited to those exemplified here. Among these, aliphatic glycols are preferable, and aliphatic glycols having 6 or less carbon atoms are particularly preferable. These may be used alone or in combination of two or more.

The polybasic acid or its acid anhydride used for obtaining the polyester (A) is not particularly limited as long as it is divalent or higher, and maleic acid, succinic acid, fumaric acid, adipic acid, Examples thereof include sebacic acid, azelaic acid, dodecanedioic acid, phthalic acid, isophthalic acid, terephthalic acid, hexahydrophthalic acid, methylhexahydrophthalic acid, trimellitic acid and the like, and acid anhydrides thereof. It is not limited to the ones.
These may be used alone or in combination of two or more. Among these, aliphatic polybasic acids are preferable, and adipic acid is particularly preferable.

The polyester (A) is obtained by reacting the above-mentioned polyhydric alcohol with a polybasic acid or an acid anhydride thereof, has a terminal hydroxyl group, and has a molecular weight of 200.
Is in the range of up to 5000. When the molecular weight of the polyester (A) is less than 200, the intended low-melting point polyester polyol cannot be obtained, and when the molecular weight of the polyester (A) exceeds 5000, the obtained polyester polyol has high viscosity and poor workability. Therefore, none of them can achieve the object of the present invention.

Such a polyester (A) contains the polyhydric alcohol and the polybasic acid or its acid anhydride, preferably in the presence of an esterification catalyst, in a molar ratio of n + 1.
It can be easily obtained by reacting as (polyhydric alcohol) / n (polybasic acid or acid anhydride thereof). As the esterification catalyst for the above reaction, sulfuric acid, a strong acid such as paratoluenesulfonic acid, an organic titanium compound such as tetramethyl titanate, tetraethyl titanate, tetrapropyl titanate, tetrabutyl titanate, dibutyltin dilaurate, tin octylate, dibutyltin oxide. Known compounds such as organic tin compounds such as dibutyltin acetate, stannous halides such as stannous chloride, stannous bromide and stannous iodide can be used. The number of functional groups per molecule of this polyester (A) (total of hydroxyl group and carboxyl group)
Is preferably 2.5 or less on average in the sense of avoiding gelation of the reaction system during the dehydration esterification reaction.

Further, as the polyester having a hydroxyl group at the terminal and suitable as the polyester (A), Clapol P-2010 (manufactured by Kuraray Co., Ltd., poly-3-methyl-1,5-pentylene adipate) is preferable. , Polylite OD-X-2340 (Dainippon Ink and Chemicals, Inc.)
And polyethylene adipate) are commercially available.

The second raw material component of the polyester polyol of the present invention is a polyfunctional alcohol (B) having 3 to 15 carbon atoms and having a valence of 3 or more, and is not particularly limited as long as it is a polyfunctional alcohol satisfying this requirement. . Specific examples thereof include glycerin, trimethylolpropane, trimethylolethane, 1,2,6-hexanetriol, 1,2,4-butanetriol, erythritol, pentaerythritol, sorbitol, dipentaerythritol and tripentaerythritol. However, the present invention is not limited thereto. These may be used alone or in combination of two or more. Among these, a hexafunctional polyfunctional alcohol is preferable, and dipentaerythritol is particularly preferable.

The polyester polyol according to the present invention is
It is necessary that any one of the following items 1 to 3 and their number average molecular weight be in the range of 1,000 to 10,000. The polyester (A) and the polyfunctional alcohol (B) are subjected to ring-opening polymerization of ε-caprolactone (C),
Further, those obtained by subjecting these ring-opening polymerization products to transesterification reaction, ε-caprolactone (C) is subjected to ring-opening polymerization to the polyfunctional alcohol (B), and this ring-opening polymerization product (Bc) is obtained. A product obtained by subjecting the polyester (A) to a transesterification reaction, and the polyester (A) having ε-caprolactone (C).
Obtained by subjecting the ring-opening polymerization product (A) to transesterification of the ring-opening polymerization product (Ac) and the polyfunctional alcohol (B), or the polyester (A) with ε-caprolactone (C).
By a transesterification reaction between a ring-opening polymerization product (Ac) obtained by ring-opening polymerization of ## STR3 ## and a ring-opening polymerization product (Bc) obtained by ring-opening polymerization of ε-caprolactone (C) in the polyfunctional alcohol (B) What was obtained. Even with the polyester polyol obtained as described above, if the number average molecular weight is less than 1000, a cured resin having sufficient film strength cannot be obtained, and 10000
If it exceeds, the viscosity is high and the workability is inferior, which is not preferable. Number average molecular weight is 1000-
The above-mentioned polyester polyols in the range of 10,000 have low melting points and good workability, and
It is suitable because it has excellent curing characteristics and has the same characteristics. Here, the number average molecular weight means gel permeation
Chromatographic method (hereinafter abbreviated as "GPC method")
It means the number average molecular weight in terms of standard polystyrene measured by.

Each polyester polyol of the present invention has ε
-The content of the caprolactone component is preferably in the range of 30 to 90% by weight. If the content of ε-caprolactone component is less than 30% by weight, the cured resin obtained by using this will have poor low temperature properties such as water resistance, low temperature strength and elongation, and 90% by weight. If the amount exceeds the above range or the melting point is high due to the crystallinity of polycaprolactone, both are not preferable. Furthermore, the polyester polyols of the present invention are not limited to those obtained by ring-opening polymerization of ε-caprolactone (C) alone, and ε-caprolactone and other cyclic lactones such as β-methyl-δ-valerolactone may be used. It also includes those used in combination for ring-opening polymerization. In this case, the content of the other cyclic lactone component is preferably in the range of 50% or less of the total content of the lactone component.

Each polyester polyol of the present invention has an average number of functional groups (f) in one molecule defined by the following formula (1).
Is preferably 2.5 or more, more preferably in the range of 3.5 to 6.

[0020]

## EQU00002 ## f = (ax + by) / (x + y) (1) In the formula (1), f is the average number of functional groups of the polyester polyol, a is the number of functional groups of the polyester (A), and b is polyfunctional. The number of functional groups of alcohol (B), x is
The number of moles of polyester (A) and y mean the number of moles of polyfunctional alcohol (B), respectively. Here, the functional group mainly refers to a hydroxyl group, and has an acid value of 5 KOHm described below.
Carboxyl groups are also included in the functional groups in the range of g / g or less. When f is less than 2.5, the curing speed is slow, and when it is more than 6, the pot life is extremely short, and thus both are not preferable.

The above-mentioned polyester polyols of the present invention are obtained by any of the first to fourth production methods of the present invention described below, and the polyester polyol (A) and polyfunctional alcohol (B) used as raw materials are used. Type and quantity,
In addition, by varying the amount of ε-caprolactone relative to these and the like, the molecular weight of the polyester polyol finally obtained, the ε-caprolactone component content and the average number of functional groups (f) are adjusted to the target values. Can be easily obtained.

Next, the method for producing the polyester polyol according to the present invention will be described. In each of the production methods of the present invention, the specific polyester (A) having a hydroxyl group at the terminal, the specific polyfunctional alcohol (B), and ε-caprolactone (C) are used as raw materials.

The polyester polyols of 1 to 4 of the present invention can be produced by the first to fourth production methods described below, respectively. In the first manufacturing method (the invention of claim 8), first,
The polyester (A) and the polyfunctional alcohol (B) were charged in a predetermined amount into a reactor, and a predetermined amount of ε-caprolactone (C) was further added thereto, and ε-caprolactone was subjected to ring-opening polymerization at each hydroxyl group. It is necessary to transesterify the obtained ring-opening polymerization products. In this production method, the transesterification reaction is preferably performed in the range of 180 to 250 ° C, more preferably 1
The temperature is in the range of 90 to 230 ° C. If the temperature for the transesterification reaction is lower than 180 ° C., the transesterification reaction is not sufficiently carried out, and if it is higher than 250 ° C., the depolymerization reaction of the ester chain is likely to occur, so that the above temperature range is preferable. The temperature condition during the ring-opening polymerization is usually in the range of 130 to 250 ° C., preferably 150 to
The range is 230 ° C. At this time, the types of polyester (A) and polyfunctional alcohol (B), the charging amount, the charging amount of ε-caprolactone relative to these, etc., are the characteristics of the polyester polyol to be finally obtained, particularly the molecular weight,
It can be appropriately determined in consideration of the ε-caprolactone component content, the average number of functional groups (f), and the like.

The reaction product before the transesterification reaction consists of the ε-caprolactone ring-opening polymer of the polyester (A) and the ε-caprolactone ring-opening polymer of the polyfunctional alcohol (B). The mixture of caprolactone ring-opening polymers has a high melting point and cannot be the intended polyester polyol. In this manufacturing method,
A mixture of two ε-caprolactone ring-opening polymers,
A low-melting random copolyester having a structure in which caprolactone chains and other polyester chains are randomly arranged by heating and stirring under the temperature condition of the above range to sufficiently carry out intramolecular and intermolecular transesterification reaction. The polyol can be obtained. Further, in this case, a polycondensation reaction accompanied by elimination and distillation of a low-molecular-weight glycol component may occur in parallel with the transesterification reaction, but this does not affect the practical properties of the obtained polyester polyol.

A ring-opening reaction catalyst is usually used for the ring-opening polymerization of ε-caprolactone, and the purpose is to prevent coloring of the resulting polyester polyol during ring-opening polymerization of ε-caprolactone and transesterification. Then, it is preferable to pass an inert gas such as nitrogen gas into the reaction system. As the ring-opening reaction catalyst, for example, tetramethyl titanate, tetraethyl titanate, tetrapropyl titanate, an organic titanium compound such as tetrabutyl titanate, dibutyltin dilaurate, tin octylate, dibutyltin oxide, an organic tin compound such as dibutyltin acetate,
Stannous halide compounds such as stannous chloride, stannous bromide, stannous iodide and the like can be mentioned. Furthermore, acetylacetonate compounds of various metals and organic carboxylic acid metal salts can also be used. Of these, organotitanium compounds are preferable because they exhibit sufficient catalytic activity for transesterification. The amount of catalyst added is usually,
It is in the range of 0.01 to 1000 ppm, preferably 0.1 to 100 ppm.

The second to fourth manufacturing methods of the present invention (claim 9)
~ Invention of claim 11 is as follows, and one or both of the ring-opening polymerization product (Bc) and the ring-opening polymerization product (Ac) are separately provided from the first production method. The ring-opening polymerization product (Bc) and the polyester (A) separately obtained, and the ring-opening polymerization product (A
c) and the polyfunctional alcohol (B), or the separately obtained ring-opening polymerization product (Bc) and ring-opening polymerization product (Ac) are subjected to transesterification reaction. Second production method: ε-in the polyfunctional alcohol (B)
A method of transesterifying a ring-opening polymerization product (Bc) obtained by ring-opening polymerization of caprolactone (C) and the polyester (A) having a hydroxyl group at the terminal. Third Production Method: A ring-opening polymerization product (Ac) obtained by ring-opening polymerization of ε-caprolactone (C) on the polyester (A) having a hydroxyl group at the terminal and the polyfunctional alcohol (B). Method of transesterification. Fourth production method: A ring-opening polymerization product (Ac) obtained by ring-opening polymerization of ε-caprolactone (C) on the polyester (A) having a hydroxyl group at the terminal and the polyfunctional alcohol (B). A method of subjecting a ring-opening polymerization product (Bc) obtained by ring-opening polymerization of ε-caprolactone (C) to a transesterification reaction.

Also in each of these production methods, the ring-opening polymerization of ε-caprolactone to the hydroxyl group of the polyester (A) or the polyfunctional alcohol (B) and the transesterification reaction of each of the above are both carried out in the first production method. The same temperature condition as can be used.

In each of the production methods of the present invention, the paragraph [0
023], the molecular weight, the ε-caprolactone component content, and the average number of functional groups (f) of the polyester polyol finally obtained are different from those of the polyester (A) and the polyfunctional alcohol (B) used as raw materials. It can be adjusted by variously changing the charged amount and the charged amount of ε-caprolactone relative to these. In each production method of the present invention, the number average molecular weight of the obtained polyester polyol is 1000 to 100.
00, the content of the caprolactone component is 30 to 90
It is preferable that the weight% range and the average number of functional groups (f) be 2.5 or more, and particularly 3.5 to 6.

The polyester polyol of the present invention reacts with a polyisocyanate compound and can be suitably used as a raw material for producing urethane coatings, adhesives, urethane foams, spandex fibers, etc.
It has reactivity with melamine resins and epoxy resins, and can be applied to adhesives, coating agents, etc. in combination with these resins.

[0030]

EXAMPLES Next, the present invention will be explained more specifically with reference to Examples and Comparative Examples, but the present invention is not limited to the description of these Examples unless it exceeds the gist. In addition, in the following description (including Table 1 and Table 2),
"Parts" means parts by weight and "%" means% by weight. The hydroxyl value and acid value of the obtained polyester, and the hydroxyl value, acid value, number average molecular weight, and melting point of the polyester polyol were measured and displayed by the methods described below. The f value of the polyester polyol is calculated by the formula (1) from the number of functional groups of the used polyester (A) and polyfunctional alcohol (B) and the charged amount, and the ε-caprolactone content is the polyester (A). ), Polyfunctional alcohol (B), and ε-caprolactone.

(1) Hydroxyl value (KOHmg / g) The hydroxyl value was measured by the phthalic anhydride-pyridine method in accordance with JIS K1557 (6.4). (2) Acid value (KOHmg / g) 1 / 50N based on JIS K1557 (6.6)
-Measured by an indicator titration method using a KOH methanol solution. (3) GPC method HLC-8 manufactured by Tosoh Corp. by number average molecular weight GPC method
Model 020 (Column: G3000HXL / G4000HX
L / G6000HXL) and the number average molecular weight in terms of standard polystyrene. The molecular weight of the polyester (A) having a hydroxyl group at the terminal was determined by the terminal group quantification method. (4) Melting point differential scanning calorimeter (DSC-2 manufactured by Seiko Instruments Inc.)
0) using a temperature rising rate of 20 ° C./min.
The measurement was performed in the temperature range of 0 ° C., and the melting curve obtained was shown in the temperature range from the endothermic start to the end.

Synthesis Example 1: Adipic acid 14 was added to a four-necked flask equipped with a stirrer, a thermometer, a cooling tube and a nitrogen introducing tube.
76.6 parts, 1,4-butanediol 1000.1 parts,
Then, 0.02 part of tetrabutyl titanate was charged, and a dehydration esterification reaction was carried out at a temperature of 150 to 220 ° C. for 24 hours while flowing nitrogen into the reaction system to obtain a polyester having a hydroxyl group at the terminal. Each item of the obtained polyester was measured by the above-mentioned method, and as a result, the molecular weight was 2004, the acid value was 0.5 KOHmg / g, and the hydroxyl value was 56.
It was 0 KOHmg / g.

Example 1: In a three-necked flask equipped with a stirrer, a thermometer, and a nitrogen introduction tube, 600.0 parts of the polyester having a hydroxyl group at the end obtained in Synthesis Example 1 and 121.7 parts of dipentaerythritol. , Ε-caprolactone 1
678.3 parts, and tetrabutyl titanate 0.02
Then, the reaction system was charged with nitrogen, and the mixture was heated and stirred at 210 ° C. for 6 hours while flowing nitrogen into the reaction system to carry out ring-opening polymerization of ε-caprolactone and a transesterification reaction to obtain a target polyester polyol. The obtained polyester polyol was measured for each item by the above method. The result is the kind of raw materials used,
The amount and the reaction conditions are shown in Table 1.

Example 2: In the example described in Example 1,
A desired polyester polyol was obtained in the same manner as in the same example except that the amounts of the raw materials and the like used and the reaction time were changed as shown in Table 1. The obtained polyester polyol was measured for each item by the same method as in the same example. The results are also shown in Table 1.

Example 3: In the example described in Example 1,
Polyester (A) as poly-3-methyl-1,5-pentylene adipate (molecular weight 2003, acid value 0.6 KO
Hmg / g, hydroxyl value 56.1 KOHmg / g, Kuraray Co., Ltd., Kurapol P-2010) were used, except that the amounts of each raw material and the reaction time were changed as shown in Table 1. Similarly, the intended polyester polyol was obtained. The obtained polyester polyol was measured for each item by the same method as in the same example. The results are also shown in Table 1.

Example 4: In the example described in Example 1,
Polyethylene adipate (molecular weight 1972, acid value 0.6 KOHmg / g, hydroxyl value 5 as polyester (A))
6.9 KOHmg / g, manufactured by Dainippon Ink and Chemicals, Inc.
Polylite OD-X-2340) was the same as in the same example except that trimethylolpropane was used as the polyfunctional alcohol (B) and the amounts of each raw material and the like, the reaction temperature, and the reaction time were changed as shown in Table 1. The desired polyester polyol was obtained. The obtained polyester polyol was measured for each item by the same method as in the same example. The results are also shown in Table 1.

Comparative Example 1: In the example described in Example 1,
A polyester polyol was obtained in the same manner as in the example except that the polyfunctional alcohol (B) was not charged and the amounts of the other raw materials and the like and the reaction time were changed as shown in Table 1. Regarding the obtained polyester polyol,
Each item was measured by the same method as in the same example. The results are also shown in Table 1.

Comparative Example 2: In the three-necked flask used in Example 1, 284.0 parts of 1,4-butanediol, 419.0 parts of adipic acid, and 121.7 of dipentaerythritol.
Parts, ε-caprolactone 1678.3 parts, and tetrabutyl titanate 0.02 parts were charged all at once, and the mixture was heated and stirred at 150 to 210 ° C. for 6 hours while flowing nitrogen into the reaction system to carry out dehydration esterification reaction, and Attempts were made to carry out ring-opening polymerization of ε-caprolactone and transesterification, but the reaction system as a whole gelled and the target polyester polyol could not be obtained.

[0039]

[Table 1]

Furthermore, coating compositions were prepared by blending the polyisocyanate curing agents with the polyester polyols obtained in Examples 1 to 4 and Comparative Example 1 above, and their curing characteristics (curing time and pot life) were prepared. ) Was evaluated. The method for preparing each coating composition and the method for evaluating the curing characteristics are as follows. The obtained results are shown in Table 2 below together with the composition and the like.

(1) Preparation of coating composition Each polyester polyol and hexamethylene diisocyanate trimer obtained in Examples 1 to 4 or Comparative Example 1 (polyisocyanate curing agent manufactured by Mitsubishi Kasei Co., Ltd., trade name: Mitec NY730A,) was blended at a ratio (parts by weight) as shown in Table 2 so that the equivalent ratio of isocyanate group / hydroxyl group was 1.1 / 1. (2) Evaluation of curing characteristics a. Curing time Each coating composition prepared was applied to the surface of a polyethylene sheet, left under curing conditions at a temperature of 60 ° C., and the time until no stickiness was felt when touched with a finger (min.)
Was the curing time. B. Pot life The time until each of the coating compositions immediately after compounding is left under the condition of a temperature of 23 ° C. and the viscosity measured under the condition of a temperature of 25 ° C. becomes twice the viscosity of the composition immediately after the compounding (hr ..)
Was the pot life of each composition. In addition, the viscosity is a rotational viscometer (manufactured by Tokyo Keiki Co., Ltd., VISCONIC EHD-
R) was used, and the rotation speed was 20 to 100 rpm and the measurement was performed using a standard rotor (1 ° 34 ′).

[0042]

[Table 2]

From the above Examples and Comparative Examples, the following is clear. (1) The polyester polyols obtained in Examples 1 to 4 have a low melting point and are liquid at room temperature, whereas those obtained in Comparative Example 1 are solid (wax-like). (2) In Examples 1 to 4, low-melting point polyester polyols were obtained, whereas in Comparative Example 1 in which no polyfunctional alcohol was used, only high-melting point polyester polyols were obtained, and the polyesters In Comparative Example 2 in which the raw material compound is used instead of (A), the intended polyester polyol cannot be obtained. (3) From the polyester polyols obtained in Examples 1 to 4, excellent coating compositions having sufficiently long pot life and short curing time can be obtained. On the other hand, the coating composition obtained from the polyester polyol of Comparative Example 1 has a long curing time.

[0044]

The polyester polyol of the present invention is
(1) To form a coating film having a low melting point and excellent workability, and (2) a combination of various curing agents such as polyisocyanate, melamine resin, and epoxy resin, which has excellent chemical resistance and weather resistance. In addition, (3) it can be applied to an adhesive, a coating agent, etc. in combination with the above various curing agents, and according to the production method of the present invention, a specific polyester (A) having a hydroxyl group at the end is used as a raw material Since a specific polyfunctional alcohol (B) is used, ε-caprolactone is subjected to ring-opening polymerization to these, and the obtained ring-opening polymerization products are subjected to transesterification reaction, formation of microgel during the reaction is suppressed, and Thus, it is possible to easily produce a polyester polyol having a high melting point and a low melting point and excellent curing characteristics. As described above, the present invention has the advantageous effect of providing a polycaprolactone-based polyester polyol having a wide range of applications and a method for producing the same.

─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) C08G 63/00-63/91

Claims (12)

(57) [Claims] 1. A divalent and / or 3 having 2 to 10 carbon atoms.
Obtained by the reaction of a polyhydric polyhydric alcohol with a polybasic acid or an acid anhydride thereof and having a hydroxyl group-terminated polyester (A) having a molecular weight in the range of 200 to 5,000 and a trivalent or higher valence of 3 to 15 carbon atoms To the polyfunctional alcohol (B), ε-
It is obtained by subjecting caprolactone (C) to ring-opening polymerization, and further subjecting these ring-opening polymerization products to transesterification reaction,
A polyester polyol having a number average molecular weight in the range of 1,000 to 10,000. 2. The polyfunctional alcohol (B) according to claim 1.
Is obtained by subjecting ε-caprolactone (C) to ring-opening polymerization, and subjecting the ring-opening polymerization product (Bc) to the polyester (A) according to claim 1 for transesterification, and having a number average molecular weight of 1,000 to 10,000. A polyester polyol having a range. 3. The polyester (A) according to claim 1, wherein
-Caprolactone (C) is subjected to ring-opening polymerization, and the ring-opening polymerization product (Ac) is transesterified with the polyfunctional alcohol (B) according to claim 1 to obtain a number average molecular weight of 1,000 to 10,000. A polyester polyol having a range. 4. The polyester (A) according to claim 1 having ε
A ring-opening polymerization product (Ac) obtained by ring-opening polymerization of caprolactone (C), and the polyfunctional alcohol (B) according to claim 1.
A polyester polyol obtained by subjecting a ring-opening polymerization product (Bc) obtained by ring-opening polymerization of ε-caprolactone (C) to an ester exchange reaction, and having a number average molecular weight in the range of 1,000 to 10,000. 5. The content of ε-caprolactone component is 30 to
It is in the range of 90% by weight, and the polyester polyol according to any one of claims 1 to 4. 6. The average functional group number (f) defined by the following formula (1) is 2.5 or more.
~ The polyester polyol according to claim 5. F = (ax + by) / (x + y) (1) In the formula (1), f is the average number of functional groups of the polyester polyol, a is the number of functional groups of the polyester (A), and b is polyfunctional. The number of functional groups of alcohol (B), x is the number of moles of polyester (A), and y is the number of moles of polyfunctional alcohol (B). 7. The polyester polyol according to any one of claims 1 to 6, wherein the polyfunctional alcohol (B) is dipentaerythritol. 8. A divalent and / or 3 having 2 to 10 carbon atoms.
Obtained by the reaction of a polyhydric polyhydric alcohol with a polybasic acid or an acid anhydride thereof and having a hydroxyl group-terminated polyester (A) having a molecular weight in the range of 200 to 5,000 and a trivalent or higher valence of 3 to 15 carbon atoms A method for producing a polyester polyol, characterized by subjecting a mixture with a polyfunctional alcohol (B) to ring-opening polymerization of ε-caprolactone (C), and further subjecting the obtained ring-opening polymerization products to transesterification reaction. 9. The polyfunctional alcohol (B) according to claim 8.
A method for producing a polyester polyol, which comprises subjecting the polyester (A) according to claim 8 to a transesterification reaction with the ring-opening polymerization product (Bc) obtained by subjecting ε-caprolactone (C) to ring-opening polymerization. . 10. A ring-opening polymerization product (Ac) obtained by ring-opening polymerization of ε-caprolactone (C) on the polyester (A) according to claim 8, and a polyfunctional alcohol (B) according to claim 8. ) Is transesterified. 11. A ring-opening polymerization product (Ac) obtained by ring-opening polymerization of ε-caprolactone (C) on the polyester (A) according to claim 8, and a polyfunctional alcohol (B) according to claim 8. ) Is subjected to a ring-opening polymerization with ε-caprolactone (C) to give a ring-opening polymerization product (Bc), which is subjected to a transesterification reaction. 12. The transesterification reaction is performed in the range of 180 to 250.
The method for producing a polyester polyol according to any one of claims 8 to 11, which is carried out under temperature conditions in the range of ° C.