JPH09151233A - Preparation of polyurethane - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prepare a polyurethane which has excellent low-temp. properties and flexibility and not have any tendency for crystallization by using a particular polyol as a polyol component in a reaction of a polyol component with a polyisocyanate component to prepare a polyurethane. SOLUTION: A polycarbonate polyol, having an no. average mol.wt. of 500 to 10000, comprising a diol unit represented by the formula -O-CH2 -CH (CH3 )-(CH2 )4 -CH(CH3 )-CH2 -O and/or the formula -O-CH2 CH(CH3 )-(CH2 )5 -CH(CH3 )- CH2 -O (e.g., a polycarbonate polyol prepd. by reacting 2,7-dimethyl-1,8-octanediol with diphenyl carbonate) is used as a polyol component.

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 polyurethane which is excellent in low-temperature properties, flexibility and the like and has no tendency to crystallize.

[0002]

2. Description of the Related Art Polyurethane is generally manufactured by using a polyol component such as polyether polyol, polyester polyol or polycarbonate polyol, a polyisocyanate component, and a chain extender comprising a low molecular weight compound having an active hydrogen atom, if necessary. It is used. Of these, the polyurethane obtained when a polyester polyol is used as the polyol component is inferior in hydrolysis resistance, and as a result, the surface becomes sticky or cracks occur in a relatively short period of time. Therefore, there are restrictions on usage. Further, the polyurethane obtained when a polyether polyol is used as the polyol component is sufficiently satisfactory in hydrolysis resistance, but on the other hand, it has very poor resistance to oxidative deterioration, and further, strength, elongation, etc. In terms of mechanical properties, abrasion resistance, oil resistance, and solvent resistance, it is not satisfactory.

On the other hand, when a polycarbonate polyol is used as the polyol component, it is said that the above-mentioned problems caused when a polyester polyol or a polyether polyol is used as the polyol component are improved. The low temperature properties and flexibility are not satisfactory. In order to solve these problems, it is known to use a polyester polyol copolymer or a polyester-modified polycarbonate polyol, etc., but it is considered that the obtained polyurethane sufficiently satisfies the required performance as described above. Can't say
The fact is that the introduction of ester groups causes deterioration in hydrolysis resistance, low-temperature properties, and the like.

Therefore, if it is possible to provide a polycarbonate polyurethane excellent in low temperature characteristics and flexibility,
Hydrolysis resistance, heat resistance, abrasion resistance, oil resistance, solvent resistance,
It is possible to improve the physical properties of the polycarbonate-based polyurethane having adhesiveness and the like, and its technical significance is great.

Polycarbonate polyols used in the production of conventional polyurethanes include 1,6-hexanediol polycarbonate polyols obtained by transesterification of linear diol 1,6-hexanediol and diphenyl carbonate. Known,
Such a polycarbonate polyol has a freezing point of about 46 ° C.
And shows a strong tendency to crystallize. In the polyurethane obtained from such a polycarbonate polyol, the polycarbonate polyol portion, which is a soft segment in the molecule, easily undergoes crystal hardening to lose elasticity, and the flexibility is remarkably reduced particularly in cold weather.

The strong tendency of 1,6-hexanediol polycarbonate polyol to crystallize is mitigated by introducing irregularities in the linear molecular structure. This irregularity can be caused by making the chain length of the diol component constituting the polycarbonate polyol irregular or introducing a side chain into the linear molecule portion of the polycarbonate polyol. However, it is important to adjust the degree of such irregularity within a certain range from the viewpoint of physical properties of the obtained polyurethane, particularly low temperature characteristics and flexibility. For example, as a specific example of making the chain length of the diol component irregular, 1,6-hexanediol and 1,5
A polycarbonate polyol obtained from a mixed diol of pentanediol (see JP-A-2-170813 and JP-A-2-170814), 1,4-
Polycarbonate polyols obtained from a mixed diol of butanediol and 1,5-pentanediol (see JP-A-4-7327 and JP-A-5-32754) have been proposed, but they can be obtained from these polycarbonate polyols. Polyurethane has much room for improvement in flexibility in cold weather.

Further, the irregularity achieved by introducing a side chain can effectively eliminate the crystallization tendency of the polycarbonate polyol, but it causes deterioration of physical properties such as low temperature characteristics and flexibility of the obtained polyurethane. Cheap. Thus, it can be said that it is very difficult to obtain a polycarbonate-based polyurethane excellent in low temperature characteristics and flexibility.

[0008]

DISCLOSURE OF INVENTION Problems to be Solved by the Invention As a result of repeated research to provide a polycarbonate-based polyurethane excellent in low-temperature characteristics and flexibility, the present inventors have found that 3-methyl-1,
Polycarbonate polyurethane using a polycarbonate polyol obtained from 5-pentanediol (see JP-A-60-195117) and polycarbonate polyurethane using a polycarbonate polyol obtained from 2-methyl-1,8-octanediol (see (See Japanese Laid-Open Patent Publication No. 62-22817), and has already applied for a patent.

These polycarbonate-based polyurethanes are excellent in physical properties such as hydrolysis resistance and heat resistance, and can solve the problems pointed out above. However, even with these polyurethanes, there was room for further improvement in terms of low temperature properties and flexibility. Then
An object of the present invention is to provide a polycarbonate-based polyurethane which has excellent low-temperature properties and flexibility and has no tendency to crystallize.

[0010]

Means for Solving the Problems The inventors of the present invention have made extensive studies for the purpose of solving the above problems, and as a result, completed the present invention.

That is, according to the present invention, when a polyurethane is produced by reacting a polyol component and a polyisocyanate component, the following formula (1) -O-CH ₂ -CH (CH ₃ )-(CH _{2) 4 -CH (CH 3)} -CH 2 -O- (1) and / or the following formula _{(2) -O-CH 2 -CH} (CH 3) - (CH 2) 5 -CH (CH 3) - Number average molecular weight 500 containing diol unit represented by CH ₂ -O- (2)
A method for producing a polyurethane, which comprises using from 1 to 10,000 polycarbonate polyols.

According to the present invention, it is possible to produce a polycarbonate-based polyurethane which is excellent in low-temperature properties and flexibility, is excellent in physical properties such as hydrolysis resistance and heat resistance, and has no crystallization tendency. . Moreover, the polycarbonate polyol used in the present invention is a low-viscosity liquid, and is characterized by excellent workability and workability.

In the present invention, a diol unit represented by the formula (1) and / or the formula (2), that is, a 2,7-dimethyl-1,8-octanediol unit [corresponding to the formula (1)] and / or Alternatively, the 2,8-dimethyl-1,9-nonanediol unit [corresponding to the formula (2)] may be used in any proportion in the polyol unit constituting the polycarbonate polyol, but is usually a polyol constituting the polycarbonate polyol. It is used in a proportion of 20 mol% or more in the unit. From the viewpoint of the low temperature characteristics and flexibility of the obtained polycarbonate-based polyurethane, the formula (1) and /
Alternatively, the diol unit represented by the formula (2) is preferably used in a proportion of 50 mol% or more in the polyol unit constituting the polycarbonate polyol. Above all, the total amount of polyol units is 2,7-dimethyl-1,8-octanediol unit or 2,8-dimethyl-1,9-nonanediol unit or 2,7-dimethyl-1,8-octanediol unit and 2 When it is a mixed unit of 8,8-dimethyl-1,9-nonanediol units, the resulting polyurethane has the best low-temperature characteristics and flexibility.

The 2,7-dimethyl-1,8-octanediol constituting the diol unit represented by the formula (1) is, for example, 2,7-octadiene-, which is easily mass-produced and easily available.
It can be industrially produced by hydrogenating a product obtained by reacting 2-methyl-1,8-octanedial derived from 1-ol with formalin.

Further, 2,8-dimethyl-1,9-nonanediol constituting the diol unit represented by the formula (2) is similarly mass-produced and easily available 2,7-octadiene-1-. It can be industrially produced by hydrogenating the product obtained by reacting 1,9-nonanedial derived from oar with formalin.

The polycarbonate polyol used in the present invention may contain other polyol units in addition to the diol unit represented by the formula (1) and / or the formula (2). As the polyol unit, a low molecular weight polyol unit is preferably used, and examples thereof include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, 1,3-propanediol, 2-methyl-1,3-propanediol, 1,3.
-Butylene glycol, 1,4-butanediol, 2-
Methyl-1,4-butanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,
6-hexanediol, 2-methyl-1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 2,2-diethyl-1,3-propanediol, 1,4-cyclohexanediol, Examples thereof include low molecular weight diol units such as cyclohexanedimethanol. Among these, 1,4-butanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, 2-methyl-1,8-
Octanediol, 1,9-nonanediol, 1,10
-Decandiol and the like are particularly preferable because they do not deteriorate the low-temperature characteristics, flexibility and other properties of the resulting polyurethane. These low molecular weight polyol units may be used alone or in combination of two or more. Also, trimethylolpropane, trimethylolethane, glycerin, 1,2,6-hexanetriol, 1,2,4-
A unit composed of a trifunctional or higher functional low molecular weight polyol such as butanetriol may be contained.

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

The polycarbonate 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,
On the other hand, when the number average molecular weight is more than 10,000, the resulting polyurethane has poor mechanical properties such as flexibility and mechanical strength. It is more preferable that the number average molecular weight of the polycarbonate polyol is in the range of 700 to 6000.

The method for producing the polycarbonate polyol used in the present invention is not particularly limited, and known polycarbonate synthesizing means can be applied. For example, 2,7-dimethyl-1,8-octanediol or 2,8-dimethyl-1,9-nonanediol, or 2,7-dimethyl-1,8-octanediol and 2,8
A mixture of dimethyl-1,9-nonanediol, or 2,7-dimethyl-1,8-octanediol and / or
Or a method of reacting a low-molecular diol mixture containing 2,8-dimethyl-1,9-nonanediol with phosgene in a predetermined ratio, 2,7-dimethyl-1,8-octanediol or 2,8-dimethyl- 1,9-nonanediol or 2,7-dimethyl-1,8-octanediol and 2,8
A mixture of dimethyl-1,9-nonanediol, or 2,7-dimethyl-1,8-octanediol and / or
Or a low-molecular diol mixture containing 2,8-dimethyl-1,9-nonanediol and ethylene carbonate,
A method in which alkylene carbonate such as propylene carbonate is charged at a desired ratio and transesterified, 2,7-dimethyl-1,8-octanediol or 2,8-dimethyl-1,9-nonanediol, or 2,7- Dimethyl-1,8-octanediol and 2,8
A mixture of dimethyl-1,9-nonanediol, or 2,7-dimethyl-1,8-octanediol and / or
Alternatively, a low-molecular diol mixture containing 2,8-dimethyl-1,9-nonanediol and dimethyl carbonate,
Examples thereof include a method in which a dialkyl carbonate such as diethyl carbonate or a diaryl carbonate such as diphenyl carbonate is charged at a desired ratio and transesterified.

In the present invention, as the polyol component to be reacted with the polyisocyanate component, in addition to the polycarbonate polyol containing the diol unit represented by the formula (1) and / or the formula (2), other polyether polyol, polyester polyol, etc. It is also possible to add and use the polyol. These other polyols are usually used in the range of 40% by weight or less based on the total polyol component.

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. Also, if necessary,
It is also possible to use tri- or higher functional polyisocyanates such as triisocyanates. 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, Diols such as 1,4-bis (β-hydroxyethoxy) benzene, 1,4-cyclohexanediol, bis (β-hydroxyethyl) terephthalate, hydrazine, ethylenediamine, propylenediamine, butanediamine, hexamethylenediamine, xylylenediamine. , Isophoronediamine, piperazine, phenylenediamine, tolylenediamine, adipic acid dihydrazide, isophthalic acid dihydrazide and the like.
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 desired polyurethane, etc., but is usually 10 mol or less, preferably 0. It is in the range of 2 to 6 mol. Further, in the present invention, optional components such as a catalyst, a reaction accelerator, a foaming agent, an internal mold release agent, a filler, a reinforcing agent, a face dye, a stabilizer and the like which are usually used in the production of polyurethane are used as necessary. Can be used.

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 polycarbonate 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. As a specific example of the method for producing the polyurethane of the present invention, a polycarbonate polyol and a low molecular weight compound having an active hydrogen atom (chain extender, etc.) are mixed to give a mixture of 40 to 10
The mixture was heated to 0 ° C., and the resulting mixture had a molar ratio of active hydrogen atoms to isocyanate groups of 1: 1 to 1: 1.
A method for producing polyurethane by adding polyisocyanate in an amount of 1.5 and stirring for a short time, and then heating to, for example, 50 to 160 ° C., a polycarbonate polyol, a mixture of a low molecular compound having an active hydrogen atom and a polyisocyanate For example 1
A method of producing polyurethane by kneading at a high temperature of 80 to 260 ° C., a polycarbonate polyol, a low molecular compound having an active hydrogen atom, a polyisocyanate, etc. are continuously supplied to an extruder such as a multi-screw extruder, and for example, 18
A method of producing polyurethane by continuous melt polymerization at a high temperature of 0 to 260 ° C., a polycarbonate polyol, a method of performing a polyurethane forming reaction of a low molecular weight compound having an active hydrogen atom and polyisocyanate in an organic solvent, and the like.

Among these, when the concentration of the polycarbonate polyol, the low molecular weight compound having an active hydrogen atom and the polyisocyanate is controlled when the polyurethane is produced by the above-mentioned method, a high molecular weight polyurethane can be easily produced. it can. At this time, the concentration of the polycarbonate polyol, the low molecular weight compound having an active hydrogen atom and the polyisocyanate is 10 to 40% by weight.
It is preferable to be within the range. 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 according to the present invention is excellent in low-temperature properties and flexibility, and is also excellent in physical properties such as hydrolysis resistance and heat resistance. Therefore, various binders, paints, coating agents and adhesives are used. , Fiber treatment agent, sheet, film, roll, gear, solid tire, belt, hose, tube, packing material, anti-vibration material, shoe sole,
It can be used in a wide variety of applications such as sports shoes, machine parts, automobile parts, sports equipment, elastic fibers, artificial leather and the like.

[0028]

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 polycarbonate polyol, low temperature characteristics and mechanical performance (flexibility) of the obtained polyurethane [100% modulus (hereinafter, abbreviated as M ₁₀₀ ) ), 200% modulus (hereinafter abbreviated as M ₂₀₀ ), 300% modulus (hereinafter abbreviated as M ₃₀₀ ), 400% modulus (hereinafter abbreviated as M ₄₀₀ )] are evaluated as follows. By the method.

◎ Measurement of number average molecular weight It was calculated based on the hydroxyl value of the polycarbonate polyol. ◎ Evaluation of low temperature characteristics A polyurethane film of about 10 mg was formed, and this film was analyzed by a differential scanning calorimetry (DSC) device to obtain -15
The glass transition temperature (° C) was obtained by raising the temperature from 0 ° C at a rate of 10 ° C / min and used as an index of low temperature characteristics. The lower the glass transition temperature, the better the low temperature properties. ◎ Evaluation of mechanical performance (flexibility) Evaluation was performed 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, using an Instron universal testing machine (manufactured by Instron), at room temperature, a pulling speed of 50
It was measured M _100, M _200, M ₃₀₀ and M ₄₀₀ in cm / min.

Reference Example 1 (Production of Polycarbonate Polyol) 2,7-Dimethyl-1,8-octanediol 1890
g and 2140 g of diphenyl carbonate were charged into a reactor and heated to 200 ° C. under a normal pressure and a nitrogen atmosphere to carry out an ester exchange reaction while distilling generated water out of the system. After gradually raising the reaction temperature to 210 to 220 ° C. and distilling most of the produced phenol out of the reaction system, the reaction was continued while reducing the pressure to 6 to 10 mmHg with a vacuum pump,
The phenol was completely distilled off. As a result, the hydroxyl value is 5
A polycarbonate polyol having a value of 6.1 KOHmg / g, an acid value of 0.2 KOHmg / g and a number average molecular weight of 2000 (hereinafter abbreviated as polycarbonate polyol A) was obtained.

Reference Examples 2 to 9 Reference Example 1 except that the low molecular weight diols shown in Table 1 were used.
A transesterification reaction was carried out in the same manner as above to obtain a polycarbonate polyol (hereinafter, the polycarbonate polyols obtained in Reference Examples 2 to 9 are abbreviated as polycarbonate polyols B to I, respectively). Among Polycarbonate Polyols A to I, Polycarbonate Polyol A
.About.F and I were liquid at room temperature (25.degree. C.), and polycarbonate polyols G and H were waxy or solid at room temperature (25.degree. C.).

[0032]

[Table 1]

In Table 1, low molecular diols are indicated by the following abbreviations. DMOD: 2,7-dimethyl-1,8-octanediol DMND: 2,8-dimethyl-1,9-nonanediol MOD: 2-methyl-1,8-octanediol ND: 1,9-nonanediol MPD: 3-methyl-1,5-pentanediol

Examples 1-5 and Comparative Examples 1-4 Polycarbonate polyol A obtained in Reference Examples 1-9
Polyurethane was produced by the following method using each of the compounds I to I. That is, each of 0.05 mol (100 g) of polycarbonate polyols A to I, 0.10 mol (9 g) of 1,4-butanediol, 0.15 mol (37.5 g) of 4,4′-diphenylmethane diisocyanate and dimethylformamide. 340 g of (DMF) was added and reacted at 80 ° C. for 6 to 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, the low-temperature characteristics and mechanical performance (flexibility) were evaluated by the methods described above. Table 2 shows the results.

[0035]

[Table 2]

From the results of Table 2, the diol unit represented by the formula (1) and / or the formula (2) (that is, 2,7-dimethyl-1,8-octanediol unit and / or 2,8-dimethyl- Polycarbonate polyols A to E containing 1,9-nonanediol units) (Examples 1 to 5) and polycarbonate polyol F containing no diol unit represented by formula (1) or formula (2) It is clear that the physical properties of the obtained polyurethanes differ as follows when compared with the cases of using ~ I (Comparative Examples 1 to 4).

That is, the polyurethanes obtained in Examples 1 to 5 have a low glass transition temperature and excellent low-temperature characteristics as compared with the polyurethanes obtained in Comparative Examples 1 to 4. Further, the polyurethanes obtained in Examples 1 to 5 are 100 to 4
In the stress (M ₁₀₀ , M ₂₀₀ , M ₃₀₀ and M ₄₀₀ ) with respect to a strain of 00%, the polyurethane obtained in Comparative Example 1 or 4 shows a value which is almost equal to or slightly smaller than that of the polyurethane obtained in Comparative Example 1 or 4 (M ₁₀₀ and M
₂₀₀ ) and shows a small value in a large strain region (M ₃₀₀ and M ₄₀₀ ), which is excellent in flexibility. Further, as compared with the crystalline polyurethane obtained in Comparative Example 2 or 3, the stress (M ₁₀₀ ,
The values of M ₂₀₀ , M ₃₀₀ and M ₄₀₀ ) are all small, and the flexibility is excellent.

[0038]

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to produce a polycarbonate-based polyurethane which is excellent in low-temperature characteristics and flexibility and has no crystallization tendency by using industrially available raw materials. Moreover, the polycarbonate polyol used in the present invention is a low-viscosity liquid, and is characterized by excellent workability and workability.

Claims (1)

[Claims] 1. When a polyurethane is produced by reacting a polyol component and a polyisocyanate component, the following formula (1) —O—CH ₂ —CH (CH ₃ ) — (CH ₂ ) ₄ — _{CH (CH 3) -CH 2 -O-} (1) and / or the following formula _{(2) -O-CH 2 -CH} (CH 3) - (CH 2) 5 -CH (CH 3) -CH 2 -O -Number average molecular weight 500 containing diol unit represented by (2)
A method for producing a polyurethane, which comprises using from 1 to 10,000 polycarbonate polyols.