JPH093149A - Production of polyurethane - Google Patents

Abstract

(57) [Summary] [Structure] When a polyol component and a polyisocyanate component are reacted to produce a polyurethane, the following formula (1) —CO—CH ₂ —CH (CH ₃ ) —CH ₂ —CO is used as the polyol component. - (1) polycarboxylic acid units and formula mainly composed of dicarboxylic acid units represented by _{(2) -O-CH 2 -CH} 2 -CH (CH 3) -CH 2 -CH 2 -O- (2 ) A method for producing a polyurethane, comprising using a polyester polyol having a number average molecular weight of 500 to 10000, which is composed of a polyol unit mainly composed of a diol unit represented by: [Effects] According to the present invention, a polyester which is excellent in hydrolysis resistance and flexibility and has no crystallization tendency by using industrially available raw materials, is also excellent in mechanical properties such as strength. A system polyurethane can be manufactured. In addition, the polyester polyol used in the present invention is a liquid having a low viscosity, and is also excellent in processability and workability.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a polyurethane which is excellent in hydrolysis resistance and flexibility and has no crystallization tendency.

[0002]

2. Description of the Related Art In the production of polyurethane, generally, a polyol component such as a polyether polyol or a polyester polyol and a polyisocyanate component, and optionally a chain extender comprising a low molecular weight compound having an active hydrogen atom are used. There is. Among them, as the polyol component, the polyester polyol is superior to the polyether polyol in terms of abrasion resistance, strong elongation, oil resistance, solvent resistance, adhesive performance and the like of the obtained polyurethane. However, when a polyester polyol having the same molecular weight and a polyether polyol having the same molecular weight are compared, the polyester polyol having a large intermolecular cohesive force is a liquid or a solid having a high viscosity. On the other hand, when polyurethane is used as a solvent-free type or high solid for various wide-ranging uses, the polyol component as a raw material is liquid at room temperature, and the one having a low viscosity is excellent in workability, and Polyether polyols, especially polypropylene polyols, are preferred because of their high convenience in adding fillers and pigments.
However, the polyurethane obtained by using polypropylene polyol has very poor light resistance, and has problems in mechanical strength, abrasion resistance and adhesiveness.

In order to solve these problems, it is known to use a polyester polyol copolymer or a polyester-modified polyether polyol, and the obtained polyurethane sufficiently satisfies the above-mentioned required performance. However, the fact is that introduction of ester groups causes deterioration of hydrolysis resistance, flexibility, mold resistance, solvent resistance and the like.

Therefore, if it is possible to provide a polyester polyurethane having excellent hydrolysis resistance and flexibility,
It is possible to improve the physical properties of polyester-based polyurethane with abrasion resistance, oil resistance, solvent resistance, adhesion performance, etc.,
Its technical significance is great.

As a versatile polyester polyurethane having relatively good hydrolysis resistance, polycaprolactone polyol, polyester polyol obtained from 1,6-hexanediol, neopentyl glycol and adipic acid, and 3-methyl have been conventionally used. Polyester polyurethanes using a polyester polyol obtained from -1,5-pentanediol and adipic acid are known, but these polyester polyurethanes are not sufficiently satisfactory in hydrolysis resistance.

As the polyester polyurethane having excellent hydrolysis resistance, a ring-opening polymer or a ring-opening copolymer of β-methyl-δ-valerolactone is used as a polyol component in JP-A-60-26019. The polyester-based polyurethane described above is disclosed in JP-A-61-18552.
In JP-A-0,009, a polyester-based polyurethane using a polyester polyol obtained by reacting a low-molecular-weight polyol mixture of 1,9-nonanediol and a branched alkylenediol with a dicarboxylic acid such as adipic acid or azelaic acid is disclosed. In JP 63-156820 A, 2-methylpentanedioic acid and 2-methyl-
A polyester-based polyurethane using 1,5-pentanediol has been proposed. However, JP-A-60
Since the ring-opening polymer or ring-opening copolymer of β-methyl-δ-valerolactone described in JP-A-26019 is thermodynamically unstable, it causes depolymerization during storage or during production of polyurethane. It is necessary to handle it carefully so that it is complicated in work. In addition, JP-A-61
The polyester polyol obtained by reacting a low molecular weight polyol mixture of 1,9-nonanediol and a branched alkylenediol with a dicarboxylic acid such as adipic acid or azelaic acid, described in JP-A-185520, is in a wax form or a solid form. And when manufacturing polyurethane,
There is a problem that workability and workability are poor. In addition, the method described in JP-A-63-156820
Polyurethanes using polyester polyols derived from methylpentanedioic acid and 2-methyl-1,5-pentanediol are not satisfactory in terms of hydrolysis resistance.

On the other hand, as the polyol component, for example, 1,
A polycarbonate-based polyurethane using a polycarbonate polyol having excellent hydrolysis resistance such as 6-hexanediol polycarbonate has also been proposed, and the above-mentioned drawbacks caused when a polyether polyol is used as a polyol component are improved. It is said that
Polycarbonate polyol is extremely expensive and has a problem of poor cold resistance.

[0008]

DISCLOSURE OF INVENTION Problems to be Solved by the Invention As a result of repeated research to provide a polyester-based polyurethane having excellent hydrolysis resistance using industrially available raw materials,
3-methylpentanedioic acid, ethylene glycol, 1,
Polyester polyurethane using polyester polyol obtained by reaction with glycols such as 4-butanediol and 1,6-hexanediol (Japanese Patent Laid-Open Publication No. 6-58242).
No. 0-26018) and a polyester-based polyurethane using a polyester polyol obtained by the reaction of 3-methylpentanedioic acid with 1,9-nonanediol (see JP-A-5-262842), which has already been patented. I am applying.

These polyester-based polyurethanes are
In addition to being excellent in hydrolysis resistance, it can solve the problems pointed out above. However, even with these polyurethanes, flexibility was insufficient and room for improvement was recognized.

Therefore, it is an object of the present invention to provide a polyester-based polyurethane which is excellent in hydrolysis resistance and flexibility and does not have a tendency to crystallize by using industrially available raw materials.

[0011]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventors have found that branched glycols are used as a diol component to be combined with 3-methylpentanedioic acid which is a dicarboxylic acid component. It was found that the use of the polyester-based polyurethane can improve the flexibility without impairing the hydrolysis resistance of the polyester-based polyurethane, and as a result of further study, the present invention has been completed.

That is, in the present invention, when a polyurethane is produced by reacting a polyol component and a polyisocyanate component, the following formula (1) —CO—CH ₂ —CH (CH ₃ ) —CH ₂ —CO is used as the polyol component. - (1) polycarboxylic acid units and formula mainly composed of dicarboxylic acid units represented by _{(2) -O-CH 2 -CH} 2 -CH (CH 3) -CH 2 -CH 2 -O- (2 ) A method for producing a polyurethane, which comprises using a polyester polyol having a number average molecular weight of 500 to 10,000, which is composed of a polyol unit mainly composed of a diol unit represented by:

According to the present invention, it is possible to produce a polyester-based polyurethane which is excellent in hydrolysis resistance and flexibility, and has no mechanical tendency such as crystallization so that it is also excellent in mechanical properties such as strength. The polyester-based polyurethane obtained by the present invention is extremely useful for a wide variety of uses. In addition, the polyester polyol used in the present invention is a low-viscosity liquid and has the feature of being excellent in processability and workability.

In the present invention, "mainly composed of a dicarboxylic acid unit represented by the formula (1)" means that at least 50 mol% or more of the polycarboxylic acid units constituting the polyester polyol are represented by the formula (1). Is a dicarboxylic acid unit, i.e. a 3-methylpentanedioic acid unit.

When the content of the dicarboxylic acid unit represented by the formula (1) in the polycarboxylic acid unit constituting the polyester polyol is less than 50 mol%, the resulting polyester polyurethane has hydrolysis resistance and flexibility. descend. The content of the dicarboxylic acid unit represented by the formula (1) in the polycarboxylic acid unit constituting the polyester polyol is preferably 60 mol% or more, and above all, the content of the dicarboxylic acid unit represented by the formula (1) is When the content is 100%, that is, when the total amount of polycarboxylic acid units is 3-methylpentanedioic acid units, the resulting polyurethane has the best hydrolysis resistance and flexibility.

Here, the dicarboxylic acid unit of the formula (1) is 3
-Derived from methylpentanedioic acid or an alkyl ester of 3-methylpentanedioic acid. 3-Methylpentanedioic acid is produced in large quantities and is easily available.
It can be industrially produced from 1,5-pentanediol, β-methyl-δ-valerolactone or 2-hydroxy-4-methyltetrahydropyran by an oxygen oxidation method.

The polyester polyol used in the present invention may contain other polycarboxylic acid units in addition to the dicarboxylic acid unit represented by the formula (1).
Examples of the polycarboxylic acid unit include those represented by the following formula (3) —CO—R—CO— (3) [wherein, R is a divalent saturated aliphatic hydrocarbon group having 2 to 20 carbon atoms (provided that it is 2-methyl). A carboxylic acid group other than a propylene group), a saturated alicyclic hydrocarbon group or an aromatic hydrocarbon group is represented], and examples thereof include succinic acid, methylsuccinic acid, glutaric acid, adipic acid, suberic acid and methylhexane. Saturated aliphatic dicarboxylic acid units such as diacids, azelaic acid and sebacic acid, saturated alicyclic dicarboxylic acid units such as cyclohexanedicarboxylic acid, phthalic acid,
Examples thereof include aromatic dicarboxylic acid units such as terephthalic acid and isophthalic acid. Among these, saturated aliphatic dicarboxylic acid units such as adipic acid, azelaic acid, methylhexanedioic acid and sebacic acid are particularly preferable because they do not significantly reduce the hydrolysis resistance and flexibility of the resulting polyurethane. The content of the dicarboxylic acid unit represented by the formula (3) is
It is desirable that the amount is less than 50 mol% with respect to the total amount of polycarboxylic acid units constituting the polyester polyol.

The polycarboxylic acid unit to be coexisted with the dicarboxylic acid unit represented by the formula (1) may be one kind or two or more kinds. It is also possible to contain a polycarboxylic acid unit having a functionality of 3 or more.

Further, in the present invention, "mainly composed of a diol unit represented by the formula (2)" means at least 5 out of the polyol units constituting the polyester polyol.
It means that 0 mol% or more consists of a diol unit represented by the formula (2), that is, a 3-methyl-1,5-pentanediol unit. When the content of the diol unit represented by the formula (2) in the low-molecular-weight polyol unit constituting the polyester polyol is less than 50 mol%, the resulting polyester-based polyurethane has hydrolysis resistance, flexibility, mechanical properties, and the like. Physical properties of. Formula (2) in the polyol unit constituting the polyester polyol
The content of the diol unit represented by is preferably 60 mol% or more, and above all, the content of the diol unit represented by the formula (2) is 100 mol%, that is, the total amount of the polyol unit is 3-methyl- When it is a 1,5-pentanediol unit, the resulting polyurethane has the best hydrolysis resistance and flexibility.

3-Methyl-1,5-pentanediol which constitutes the diol unit represented by the formula (2) is a compound which has been produced in a large amount and is easily available.

The polyester polyol used in the present invention may contain other polyol units in addition to the diol unit represented by the formula (2). A low-molecular-weight polyol unit is preferably used as the polyol unit, and examples thereof include 1,4-butanediol, 2-methyl-1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, and 2; -Methyl-1,8-
Octanediol, 1,9-nonanediol, 1,10
And low molecular weight diol units such as decanediol and 2,2-diethyl-1,3-propanediol. These low molecular weight polyol units may be used alone,
Two or more kinds may be used as a mixture. Moreover, you may contain the unit which consists of trifunctional or more low-molecular-weight polyols, such as trimethylol propane.

The content of these low molecular weight polyol units is
It is desirable that the amount is less than 20 mol% with respect to the total amount of polyol units constituting the polyester polyol.

The polyester polyol used in the present invention may have a partial structure such as a polyether polyol unit or a polycarbonate polyol unit in the molecule, as long as the gist of the present invention is not impaired.

The polyester polyol used in the present invention is required to have a number average molecular weight of 500 to 10,000. If the number average molecular weight is less than 500, the resulting polyurethane will have poor low-temperature properties, while if it is greater than 10,000, the resulting polyurethane will have poor mechanical properties. It is more preferable that the number average molecular weight of the polyester polyol is in the range of 700 to 6000.

The method for producing the polyester polyol used in the present invention is not particularly limited, and a known polyester polycondensation method can be applied. For example, 3-methylpentanedioic acid or its alkyl ester or a dicarboxylic acid mixture containing it, and 3-methyl-1,5-
By charging pentanediol or a diol mixture containing it at a desired ratio, an esterification or transesterification reaction is carried out, and the obtained reaction product is further polycondensed at high temperature in a vacuum in the presence of a polycondensation catalyst. Polyester polyols can be produced.

In the present invention, as the polyol component to be reacted with the polyisocyanate component, other polyols such as polyether polyol and polycarbonate polyol may be added and used in addition to the above polyester polyol. These polyether polyols and polycarbonate polyols are usually used in the range of 40% by weight or less based on all the polyol components.

The polyisocyanate component used in the present invention is not particularly limited, and any polyisocyanate conventionally used in the production of polyurethane can be used. Examples of such polyisocyanates include 4,4'-diphenylmethane diisocyanate, tolylene diisocyanate, phenylene diisocyanate, 1,5-naphthylene diisocyanate, 3,
Aromatic diisocyanates such as 3'-dichloro-4,4'-diphenylmethane diisocyanate, xylylene diisocyanate and toluylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, hydrogenated xylylene diisocyanate and other fats Examples thereof include group or alicyclic diisocyanates.
These polyisocyanates may be used alone or in combination of two or more. Further, if necessary, triisocyanate or another polyfunctional isocyanate having a functionality of 3 or more can be used. In this case a thermosetting polyurethane is formed.

Further, in the present invention, a chain extender can be used if necessary. As the chain extender, it is preferable to use a low molecular weight compound having two or more active hydrogen atoms. Examples of such a low molecular weight compound include ethylene glycol, 1,4-butanediol, 1,6-hexanediol, 1,4-bis (β-hydroxyethoxy)
Benzene, 1,4-cyclohexanediol, bis (β
-Hydroxyethyl) terephthalate and other diols,
Hydrazine, ethylenediamine, propylenediamine,
Examples include butanediamine, hexamethylenediamine, xylylenediamine, isophoronediamine, piperazine, phenylenediamine, tolylenediamine, adipic acid dihydrazide, and isophthalic acid dihydrazide. These low molecular compounds may be used alone or in combination of two or more. The amount of the chain extender used is not particularly limited and is appropriately selected according to the hardness to be imparted to the target polyurethane, etc., but is usually in the range of 10 mol or less per mol of the polyester polyol, and 0.2 to It is desirable to set it in the range of 6 mol.

Further, in the present invention, a catalyst, a reaction accelerator, a foaming agent, which are usually used in the production of polyurethane,
Any components such as an internal mold release agent, a filler, a reinforcing agent, a face dye, and a stabilizer can be used if necessary.

In the present invention, when a polyurethane is produced by reacting a polyol component and a polyisocyanate component, the polyisocyanate component is used for the total amount of active hydrogen atoms contained in the polyester polyol, the chain extender and other components. It is preferable to use it in such a ratio that the number of moles of the isocyanate group per 1 mol of the active hydrogen atom is 0.9 to 1.5 mol, and it is more preferable to use in such a ratio that it is about 1 mol. .

As the method for producing the polyurethane in the present invention, any known urethanization reaction technique can be used, and either the prepolymer method or the one-shot method may be used. A specific example of the method for producing the polyurethane of the present invention is as follows. A polyester polyol and a low molecular weight compound having an active hydrogen atom (such as a chain extender) are mixed to obtain 40 to 100 ° C.
The resulting mixture is heated to a molar ratio of active hydrogen atoms to isocyanate groups of 1: 1 to 1: 1.
After adding a polyisocyanate in an amount of 5 and stirring for a short time, for example, a method of producing polyurethane by heating to 50 to 160 ° C., a polyester polyol, a mixture of a low molecular compound having an active hydrogen atom and a polyisocyanate is, for example, 180
A method for producing polyurethane by kneading at a high temperature of ˜260 ° C., polyester polyol, a low molecular compound having an active hydrogen atom, polyisocyanate, etc. are continuously fed to an extruder such as a multi-screw type extruder, and for example, 180 ~
Examples include a method of producing polyurethane by continuous melt polymerization at a high temperature of 260 ° C., a method of carrying out a polyurethane-forming reaction of a polyester polyol, a low molecular weight compound having an active hydrogen atom and polyisocyanate in an organic solvent.

Among these, polyester polyol,
By controlling the concentrations of the low molecular weight compound having an active hydrogen atom and the polyisocyanate, a high molecular weight polyurethane can be easily produced. At this time, the concentrations of the polyester polyol, the low molecular weight compound having an active hydrogen atom and the polyisocyanate are preferably in the range of 10 to 40% by weight. As the organic solvent, dimethylformamide, dimethylacetamide, dimethyl sulfoxide, tetrahydrofuran, toluene, methyl ethyl ketone, ethyl acetate, isopropanol, ethyl cellosolve and the like can be used. These solvents may be used alone or in combination of two or more.

The polyurethane obtained by the present invention is excellent in hydrolysis resistance and flexibility, and is also excellent in mechanical properties such as strength. Sheets, films, rolls, gears, solid tires, belts and hoses. Wide range of applications such as tubes, packing materials, anti-vibration agents, shoe soles, sports shoes, machine parts, automobile parts, sporting goods, elastic fibers, artificial leather, fiber treatment agents, adhesives, coating agents, binders, paints, etc. Can be used for

[0034]

EXAMPLES The present invention will be described below in more detail with reference to examples, but the present invention is not limited to these examples.

In the following examples, comparative examples and reference examples, the number average molecular weight of polyester polyol, the mechanical performance of polyurethane (breaking strength and breaking elongation), and hydrolysis resistance were evaluated by the following methods. went. ◎ Measurement of number average molecular weight It was calculated based on the hydroxyl value of the polyester polyol. ◎ Evaluation of mechanical performance Evaluation was made according to the method specified in JIS K7311. That is, a polyurethane film having a thickness of 100 μm was formed, and a dumbbell-shaped test piece was produced from this film. Using the obtained test piece, the breaking strength and the breaking elongation were measured at a tensile speed of 50 cm / min using an Instron universal testing machine (manufactured by Instron). ◎ Evaluation of hydrolysis resistance A 100 μm thick polyurethane film was formed, and this film was allowed to stand in hot water at 100 ° C. for 7 days, and the breaking strength of the film was measured at a tensile speed of 50 cm / min. The retention rate (%) of the breaking strength was calculated according to the following formula and used as an index of hydrolysis resistance.

[0036]

[Equation 1]

Reference Example 1 (Production of Polyester Polyol) 560 g of 3-methyl-1,5-pentanediol and 452 g of 3-methylpentanedioic acid were charged in a reactor, and water produced at 200 ° C. under normal pressure was taken out of the system. The esterification reaction was performed while distilling off. When about 100 g of water was distilled, 15 mg of tetraisopropyl titanate was added, and 200
The reaction was continued while reducing the pressure to １００100 mmHg. When the acid value reached 1.0 KOHmg / g, the degree of vacuum was gradually raised by a vacuum pump to complete the reaction. As a result, a hydroxyl value of 56.1 KOHmg / g and an acid value of 0.2 KOHmg / g
Polyester polyol having g and number average molecular weight of 2000 (hereinafter, abbreviated as polyester polyol A)
I got

Reference Examples 2 to 6 An esterification reaction and a polycondensation reaction were carried out in the same manner as in Reference Example 1 except that the dicarboxylic acid and the low molecular weight diol shown in Table 1 were used, and a polyester polyol (hereinafter referred to as Reference Example 2 The polyester polyols obtained in Example 6 were respectively referred to as polyester polyols B to F).

In Table 1, dicarboxylic acids and low molecular weight diols are shown by the following abbreviations.

MGA: 3-methylpentanedioic acid A D: adipic acid MPD: 3-methyl-1,5-pentanediol N D: 1,9-nonanediol B D: 1,4-butanediol

[0041]

[Table 1]

Examples 1 and 2 and Comparative Examples 1 to 4 Polyester polyols A to F obtained in Reference Examples 1 to 6
Each polyurethane was manufactured by the following method. That is, each of 0.05 mol (100 g) of polyester polyols A to F, 0.10 mol (9 g) of 1,4-butanediol, 0.15 mol (37.5 g) of 4,4′-diphenylmethane diisocyanate and dimethylformamide. Add 340 g of (DMF), 80 ° C
At room temperature for 8 hours to obtain a DMF solution of polyurethane (nonvolatile content 30%). The obtained DMF solution of polyurethane was cast on a glass plate and dried to obtain a dry film having a thickness of 100 μm. Using this film, mechanical performance and hydrolysis resistance were evaluated by the methods described above. The results are shown in Table 2 below.

[0043]

[Table 2]

From the results shown in Table 2, the dicarboxylic acid unit represented by the formula (1) (3-methylpentanedioic acid unit) and the diol unit represented by the formula (2) (3-methyl-1,5-).
Both of the case where polyester polyols A to C mainly composed of (pentanediol unit) are used (Examples 1 to 3) and the dicarboxylic acid unit represented by the formula (1) and the diol unit represented by the formula (2) When the polyester polyols D to F which do not contain (Comparative Examples 1 to 3) are compared, it is clear that the physical properties of the obtained polyurethane are different as follows.

That is, it is apparent that the polyurethanes obtained in Examples 1 to 3 have an increased breaking elongation and improved flexibility as compared with the polyurethanes obtained in Comparative Examples 1 to 3. Further, regarding the breaking strength, the polyurethanes obtained in Examples 1 to 3 are comparable to the polyurethanes obtained in Comparative Examples 1 to 3, and it is understood that the breaking strength is not impaired. Further, when using 3-methylpentanedioic acid (Examples 1 to 3 and Comparative Example 2), polyurethanes having excellent hydrolysis resistance were obtained, and the polyurethanes obtained in the present invention were obtained. It can be seen that the hydrolysis resistance of is not impaired.

[0046]

Industrial Applicability According to the present invention, industrially available raw materials have excellent hydrolysis resistance and flexibility, and since they have no tendency to crystallize, they have excellent mechanical properties such as strength. Polyester-based polyurethane can be produced. In addition, the polyester polyol used in the present invention is a liquid having a low viscosity, and is also excellent in processability and workability.

Claims (1)

[Claims] 1. When a polyurethane is produced by reacting a polyol component and a polyisocyanate component, the following formula (1) —CO—CH ₂ —CH (CH ₃ ) —CH ₂ —CO— (1) is used as the polyol component. Is represented by the following formula (2) —O—CH ₂ —CH ₂ —CH (CH ₃ ) —CH ₂ —CH ₂ —O— (2) A method for producing a polyurethane, which comprises using a polyester polyol having a number average molecular weight of 500 to 10,000, which is composed of a polyol unit mainly containing a diol unit.