JPH11189638A - Production of polyurethane - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a process for producing a polyurethane excellent in transparency from a diene polyol. SOLUTION: There is provided a process for producing a polyurethane by reacting a polyol component with a polyisocyanate component, wherein the polyol component used is a mixture comprising (a) 100 pts.wt. hydrogenated liquid diene polymer prepared by hydrogenating at least 50% of the aliphatic carbon-carbon double bonds in the molecular chain of an isoprene-based liquid diene polymer having a number-average molecular weight of 500-5,000 and 1.5-3.5, per molecule, hydroxyl groups and (b) 1-200 pts.wt. castor oil derived polyol.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a polyurethane having excellent transparency and excellent elastic properties.

[0002]

2. Description of the Related Art In recent years, polyurethane has been widely used for application of waterproof sheets, sealing materials, coating materials, potting materials and the like. In particular, in the above applications, it is advantageous from the viewpoint of operability and the like to obtain a polyurethane by using a liquid polymer and curing it at the time of use. Conventionally, polyols such as polyether polyols, polyester polyols, and diene polyols have been used as the above liquid polymer.However, when polyether polyols or polyester polyols are used, the resulting polyurethane has water resistance and hydrolysis resistance. Problems such as poor heat resistance or heat resistance.

[0003] On the other hand, when a diene polyol is used in the above, the resulting polyurethane has the characteristics of good elastic properties and excellent low-temperature characteristics, but the aliphatic carbon-carbon dicarbonate is contained in the molecular chain. Since it has a heavy bond, there is a problem in heat resistance and weather resistance. In order to improve such a problem, use of a hydrogenated liquid diene-based polyol obtained by hydrogenating an aliphatic carbon-carbon double bond in a molecular chain of the diene-based polyol has been proposed.

[0004]

However, conventionally known polyurethanes using a diene-based polyol including a hydrogenated product usually contain a polyether in addition to the diene-based polyol in consideration of physical properties. Polyols and polyester polyols are used in combination, and the transparency is insufficient. Thus, an object of the present invention is to provide a new method for producing a polyurethane having excellent transparency using a diene-based polyol.

[0005]

Means for Solving the Problems The inventors of the present invention have made intensive studies to solve the above-mentioned problems, and as a result, when producing a polyurethane by reacting a polyol component and a polyisocyanate component, a specific diene containing a hydroxyl group was produced. It has been found that the use of a mixture of a hydrogenated polymer and a castor oil-based polyol as a polyol component improves the transparency of the obtained polyurethane, and as a result of further studies, the present invention has been completed.

That is, according to the present invention, when a polyurethane component is produced by reacting a polyol component and a polyisocyanate component, the polyol component has (a) a number average molecular weight of 500 to 5,000 and a molecular weight of 1. 5-
An aliphatic carbon-carbon dimer in a molecular chain of a liquid diene polymer mainly composed of isoprene having 3.5 hydroxyl groups (hereinafter, the polymer before hydrogenation is abbreviated as a hydroxyl group-containing liquid polymer). A method for producing a polyurethane, comprising using a mixture of 100 parts by weight of a liquid diene polymer obtained by hydrogenating at least 50% of heavy bonds and (b) 1 to 200 parts by weight of a castor oil-based polyol. is there.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, "mainly composed of isoprene" means that at least 50 mol% of the structural units constituting the liquid polymer having a hydroxyl group is derived from isoprene (hereinafter referred to as "isoprene"). Abbreviated as isoprene unit).

If the content of the isoprene unit in the structural unit constituting the hydroxyl group-containing liquid polymer is less than 50 mol%, the transparency of the obtained polyurethane is not sufficient.
The content of the isoprene unit in the structural unit constituting the hydroxyl group-containing liquid polymer is preferably at least 60 mol%, and particularly, the content of the isoprene unit is 100 mol%.
In the case of, the transparency of the obtained polyurethane is the most excellent.

The hydroxyl group-containing liquid polymer used in the present invention may contain other structural units in addition to the isoprene units. Such other structural units include, for example, 1,3-butadiene, 1,3-pentadiene,
Structural units derived from conjugated dienes such as 3-dimethylbutadiene and phenylbutadiene; structural units derived from monomers copolymerizable with isoprene such as ethylene, propylene, isobutylene, styrene and α-methylstyrene; However, a structural unit derived from a conjugated diene is preferred, and a structural unit derived from 1,3-butadiene (hereinafter sometimes abbreviated as a butadiene unit) is more preferred. The above other structural units may be of one type or two or more types.

[0010] The hydroxyl group-containing liquid polymer must have a number average molecular weight in the range of 500 to 5,000.
When the number average molecular weight of the hydroxyl group-containing liquid polymer is smaller than 500, the obtained polyurethane does not show good elastic properties. On the other hand, when the number average molecular weight of the hydroxyl group-containing liquid polymer exceeds 5,000, the hydrogenated product of the hydroxyl group-containing liquid polymer does not show good fluidity, and the operability in producing polyurethane becomes poor. Not preferred. The number average molecular weight of the hydroxyl group-containing liquid polymer is 1,000 to 5,
It is preferably in the range of 000.

The hydroxyl group-containing liquid polymer must contain an average of 1.5 to 3.5 hydroxyl groups in one molecule. When the number of hydroxyl groups in one molecule of the hydroxyl group-containing liquid polymer is smaller than 1.5, the strength of the obtained polyurethane is not sufficient. On the other hand, when the number of hydroxyl groups in one molecule of the hydroxyl group-containing liquid polymer exceeds 3.5, the crosslink density becomes too high, and a polyurethane exhibiting good elastic properties cannot be obtained. The average number of hydroxyl groups in one molecule of the hydroxyl group-containing liquid polymer is preferably in the range of 1.8 to 3. The hydroxyl group may be located at the terminal of the molecular chain of the hydroxyl group-containing liquid polymer or in the chain, but is preferably located at the terminal of the molecular chain.

Such a hydroxyl group-containing liquid polymer can be obtained by a known method. For example, i) a method of polymerizing isoprene or a mixture of isoprene and other monomers by anionic polymerization or radical polymerization, and subjecting the obtained polymer to hydroboration or epoxidizing the polymer followed by hydrolysis. Ii) After polymerizing isoprene or a mixture of isoprene and other monomers using a bifunctional anionic polymerization initiator, an alkylene oxide such as ethylene oxide, propylene oxide, or styrene oxide is added to the active terminal of the resulting polymer. A method of reacting epichlorohydrin or the like; iii) a method of polymerizing isoprene or a mixture of isoprene and another monomer using a radical polymerization initiator having a hydroxyl group such as hydrogen peroxide.

In the present invention, the hydroxyl group-containing liquid polymer is used as a constituent component of a polyol component after hydrogenation. It is necessary that the degree of hydrogenation of the aliphatic carbon-carbon double bond in the molecular chain in the hydroxyl group-containing liquid polymer is 50% or more. When the degree of hydrogenation of the aliphatic carbon-carbon double bond in the molecular chain in the hydroxyl group-containing liquid polymer is lower than 50%, the obtained polyurethane has insufficient transparency, and also has insufficient heat resistance and durability. . The hydrogenation ratio of the aliphatic carbon-carbon double bond in the molecular chain of the hydroxyl group-containing liquid polymer is preferably at least 75%.

The hydrogenation of the hydroxyl group-containing liquid polymer can be carried out by using a known method such as a method of performing catalytic hydrogenation using a Ziegler-based homogeneous catalyst or a heterogeneous catalyst. In the above, in the case of performing hydrogenation using a homogeneous catalyst, hexane, a saturated hydrocarbon such as cyclohexane or benzene, toluene, an aromatic hydrocarbon such as xylene as a solvent, at a reaction temperature of normal temperature to 200 ° C., The hydrogenation reaction is performed under a hydrogen pressure of normal pressure to 100 kg / cm ² . As a homogeneous catalyst, a Ziegler catalyst or the like obtained by combining a transition metal halide with an alkylated product such as aluminum, an alkaline earth metal or an alkali metal may be used, with respect to an aliphatic carbon-carbon double bond in a hydroxyl group-containing liquid polymer. It is used in a ratio of about 0.01 to 0.1 mol%. The reaction time is usually 1 to 24 hours.
When hydrogenation is performed using a heterogeneous catalyst in the above, a saturated hydrocarbon such as hexane or cyclohexane or an aromatic hydrocarbon such as benzene, toluene or xylene;
Ethers such as diethyl ether, tetrahydrofuran and dioxane; alcohols such as ethanol and isopropanol or a mixture thereof as a solvent at room temperature to 2
The hydrogenation reaction is carried out at a reaction temperature of 00 ° C. and under a hydrogen pressure of normal pressure to 100 kg / cm ² . As the heterogeneous catalyst, a metal such as nickel, rhodium, palladium, ruthenium, and platinum is used alone or supported on a carrier such as silica, diatomaceous earth, alumina, and activated carbon. It is used at a ratio of about 5 to 10% by weight. The reaction time is usually 1 to 48 hours.

The castor oil-based polyol used in the present invention includes, for example, castor oil, hydrogenated castor oil, and transesterified castor oil. Commercially available castor oil-based polyols [for example, S-1-160, S-2G-120, I-AS
-2G-160R and HS-3G-250 (both trade names: manufactured by Toyokuni Oil Co., Ltd.)].
The content of the hydroxyl group in the castor oil-based polyol is usually in the range of 30 to 500 mg KO / g, preferably 100 to 200 mg KO / g, as the hydroxyl value. Also, the molecular weight of the castor oil-based polyol is
Usually, it is in the range of 100 to 4,000, preferably 50
The range is from 0 to 2,000. In the present invention, the castor oil-based polyol may use one kind,
Two or more types may be used in combination.

The amount of the castor oil-based polyol to be used must be in the range of 1 to 200 parts by weight based on 100 parts by weight of the hydrogenated liquid diene polymer. When the amount of the castor oil-based polyol is 1 part by weight or less based on 100 parts by weight of the hydrogenated liquid diene-based polymer, the transparency of the obtained polyurethane is not sufficient. The amount of castor oil-based polyol used was 200 parts by weight based on 100 parts by weight of
Exceeding the parts by weight impairs the elastic properties of the resulting polyurethane.

As the polyisocyanate component used in the present invention, polyisocyanates conventionally used in the production of polyurethane can be used. Such polyisocyanates include, for example, 4,
4'-diphenylmethane diisocyanate, tolylene diisocyanate, phenylene diisocyanate, 1,5
-Naphthylene diisocyanate, carbodiimide-modified diphenylmethane diisocyanate, polymethylene polyphenyl isocyanate, xylylene diisocyanate,
Aromatic diisocyanates such as tetramethylxylylene diisocyanate; aliphatic or alicyclic diisocyanates such as hexamethylene diisocyanate, isophorone diisocyanate, dodecane diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, and hydrogenated xylylene diisocyanate; .
One type of these polyisocyanates may be used, or two or more types may be used in combination. If necessary, a blocked polyisocyanate in which the isocyanate group of the above polyisocyanate is blocked with a blocking agent such as phenols, alcohols, oximes, and diethyl malonate can also be used.

The amount of the polyisocyanate used is not particularly limited, but the number of moles of isocyanate groups (which may be blocked) in the polyisocyanate and the hydrogenated liquid diene polymer and castor oil polyol The molar ratio of hydroxyl groups in the mixture (NCO / OH) is 0.5 to
The amount is preferably in the range of 5 and the ratio is 0.1.
More preferably, the amount is in the range of 8 to 3.

In the present invention, an organic metal compound such as dibutyltin dilaurate and dibutyltin diacetate; N, N, N ', N'-tetramethylhexane-1,
Tertiary amines such as 6-diamine and triethylenediamine;
Compounds such as imidazoles such as 1,2-dimethylimidazole can be used as the catalyst.

In the present invention, if necessary, 1,3-butanediol,
1,4-butanediol, 1,2-pentanediol,
1,6-hexanediol, 2,4-hexanediol, 2-ethyl-1,3-hexanediol, 1,4-
Cyclohexanediol, 1,4-bis (β-hydroxyethoxy) benzene, bis (β-hydroxyethyl)
The above hydrogenated liquid dienes such as terephthalate, 1,2-propylene glycol, dipropylene glycol, ethylene glycol, diethylene glycol, trimethylolpropane, etc .; low molecular weight polyols; polyether polyols; polyester polyols; polycarbonate polyols; A polyol different from the base polymer and the castor oil-based polyol can be used in combination as a polyol component or a chain extender.

Furthermore, in the present invention, polybutene, process oil, DOP (dioctyl phthalate), and alkyl phosphates such as tri-2-ethylhexyl phosphate and tricresyl phosphate are plasticized within a range not to impair the gist of the invention. You may use together as an agent. Also, if necessary, fillers, coloring agents, antioxidants, ultraviolet absorbers, light stabilizers, antistatic agents, release agents, flame retardants, foaming agents,
It is also possible to use pigments, dyes and the like in combination.

The production of the polyurethane according to the present invention can be carried out by using a known urethane-forming technique, and any one of a one-shot method and a prepolymer method may be used. A specific example of the one-shot method is as follows. That is, using a mixer, a kneader, an extruder, or the like, an additive other than the hydrogenated liquid diene-based polymer, the castor oil-based polyol and the polyisocyanate component optionally used together is added at room temperature to 200 ° C, preferably 40 to 150 ° C C. for 5 seconds to 20 hours, preferably 10 seconds to 10 hours at a temperature in the range of C. Then, the polyisocyanate component is added to the resulting mixture and reacted at a temperature in the range described above to obtain a polyurethane. Get.

Further, specific examples of the prepolymer method are as follows. That is, a mixture of a hydrogenated liquid diene polymer and a castor oil-based polyol and a polyisocyanate component are reacted within a range where the molar ratio of isocyanate groups to hydroxyl groups (NCO / OH) is 0.5 to 10 to form a prepolymer. To manufacture. The reaction temperature at this time is in the same range as in the one-shot method, and the reaction time is usually 0.5 to 5 hours.
Next, other components such as additives are blended with the obtained prepolymer, and mixed at the above reaction temperature and reaction time to obtain a polyurethane.

The polyurethane obtained by the present invention is excellent in transparency and mechanical performance such as elasticity and strength, and is used for electric and electronic parts or their protective materials, coating materials, sealing materials, waterproofing agents. It can be used for a wide range of applications, such as paints.

[0025]

EXAMPLES Hereinafter, the present invention will be described specifically with reference to examples, but the present invention is not limited to these examples.

Reference Example (Production of Hydrogenated Liquid Diene Polymer) A number average molecular weight of 2,40 obtained by polymerizing isoprene using hydrogen peroxide as a polymerization initiator was obtained.
0, liquid polyisoprene having 2.5 hydroxyl groups per molecule in cyclohexane using 5% ruthenium carbon as a catalyst at a hydrogen pressure of 50 kg / cm ² .
Hydrogenation was performed at 0 ° C. to obtain hydrogenated liquid polyisoprene (A) in which 98% of the aliphatic carbon-carbon double bonds in the liquid polyisoprene were hydrogenated. The number of hydroxyl groups per molecule of the hydrogenated liquid polyisoprene (A) was 2.5.
Further, under the same conditions as above, the above liquid polyisoprene is hydrogenated to form aliphatic carbon-
There was obtained a hydrogenated liquid polyisoprene (B) [the number of hydroxyl groups per molecule: 2.5] in which 80% of the carbon double bonds were hydrogenated.

Examples 1 to 3 and Comparative Examples 1 and 2 The hydrogenated liquid polyisoprene (A) or (B) obtained in the Reference Examples shows the castor oil-based polyols shown in Table 1 and other components. And the resulting mixture was mixed in Table 1
Was added at a ratio shown in Table 1 [an amount at which the molar ratio of isocyanate groups to hydroxyl groups (NCO / OH) becomes 1], and the mixture was stirred at 60 ° C. for 2 minutes and mixed. Next, the obtained mixture was 180 mm × 200 mm × 2 mm
, And pressed at 120 ° C. for 1 hour, and further aged at 60 ° C. for 24 hours in a nitrogen atmosphere to obtain a sheet-like molded body. Table 1 shows the transparency of the obtained molded product by a Haze value.

[0028]

[Table 1]

[0029]

According to the present invention, a polyurethane excellent in transparency can be produced by using a diene-based polyol.

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Masao Ishii 2-28 Kurashiki-cho, Nakajo-cho, Kitakanbara-gun, Niigata Pref.

Claims (1)

[Claims] When producing a polyurethane by reacting a polyol component and a polyisocyanate component, the polyol component has (a) a number average molecular weight of 500 to 50,000.
50, wherein 50% or more of the aliphatic carbon-carbon double bonds in the molecular chain of the liquid diene polymer mainly composed of isoprene having 1.5 to 3.5 hydroxyl groups per molecule are hydrogen. A method for producing a polyurethane, comprising using a mixture of 100 parts by weight of a hydrogenated liquid diene polymer added and (b) 1 to 200 parts by weight of a castor oil-based polyol.