JP3073256B2 - Polymer liquid crystal polyurethane - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel thermotropic liquid crystal polyurethane (hereinafter abbreviated as liquid crystal polyurethane).

[0002]

2. Description of the Related Art Since liquid crystalline polymer materials can be used in various fields as industrial materials, many attempts have recently been made to impart high functionality such as high strength and high elastic modulus. Thermotropic liquid crystal polymers have attracted attention as polymer materials that can be highly oriented, but can be broadly classified into two types. One is a main chain type liquid crystal polymer for the purpose of high strength and high elasticity, and the other is a side chain type liquid crystal polymer which can be applied to a recording material. Many of them relate to polyamides, polyesters and vinyl polymers, and very little research has been done on liquid crystal polyurethanes.

For example, Macromol. Chem., 182 , 2569 (1
981). And Polymers, Vol. 43, No. 5, p. 311-314 (198
6). And Macromolecules, 22 , 1467 (1989). Research on liquid crystal polyurethane is described. The liquid crystal polyurethanes described in any of (1) to (4) are all polycondensation-type polymers containing a mesogen having a rigid structure and a flexible spacer in the main chain. And, a thermotropic liquid crystal polyurethane having a relatively low molecular weight is exemplified, and the intrinsic viscosity of the polymer is about 0.2 dl / g, which is not a satisfactory value. However, for the first time, a high-molecular liquid crystal polyurethane is described. Specifically, biphenyl group as the center core, -O- as a spacer (CH _{2) m} - chain, using each containing, 4,4'-bis (6-hydroxy-hexyloxy) biphenyl as the diol component, 2,4 -Liquid crystal polyurethane is synthesized by polyaddition reaction with toluene diisocyanate. However, the intrinsic viscosity is 0.32 d
It is reported that liquid crystallinity is observed in polyurethanes exhibiting l / g, but clear liquid crystallinity is not observed in polyurethanes having a high intrinsic viscosity of about 0.57 dl / g.
These phenomena can be explained by interpreting that as the molecular weight of the polymer increases, the molecular terminal of the polyurethane bends, so that the action by the interaction of mesogen groups weakens.

Incidentally, polyurethane is a urethane bond -NHCO
A polymer containing O- as a repeating unit, generally formed by a polyaddition reaction between a diol component and a diisocyanate component to form a foam, a paint, an adhesive, an elastomer,
It is an important industrial material used as a material such as synthetic leather.

[0005]

An object of the present invention is to provide a polyurethane obtained by a polyaddition reaction between a diol component and a diisocyanate component, which has a thermotropic liquid crystal property even in a certain polymer region or more. To develop a high-molecular liquid crystal polyurethane having the following.

[0006]

Means for Solving the Problems The present inventors have conducted intensive studies in order to achieve the above-mentioned object, and as a result, a polyurethane obtained from bis (ω-hydroxyalkyleneoxy) biphenyl and a diisocyanate compound as raw materials has been obtained. The present invention has been found to have a thermotropic liquid crystallinity even in the molecular region, and it has been found that a polyurethane obtained by using 2,5-toluene diisocyanate exhibits an excellent effect as a high-molecular liquid crystal polyurethane. It was completed. That is, the present invention provides a compound represented by the following general formula (I):

[0007]

Embedded image (Wherein A is the following structural formula (Chemical Formula 7)

[0008]

Embedded image Wherein at least one of R ₁ , R ₂ and R ₃ is
An alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, or a phenyl group, or F, Cl, Br,
It represents a group represented by I or CN and CF ₃ , which may be the same or different from each other. m represents an integer of 2 to 20. The present invention relates to a polyurethane having liquid crystallinity composed of a repeating unit represented by the following formula [II]:

[0009]

Embedded image (Wherein, m represents an integer of 2 to 20). Further, the following formula [III] (Chem. 9)

[0010]

Embedded image (Wherein m represents an integer of 2 to 20), and bis (ω-hydroxyalkyleneoxy) biphenyl represented by the following formula [IV] OCN-A-NCO [IV] (where A is the following structural formula: (Formula 10)

[0011]

Embedded image Wherein at least one of R ₁ , R ₂ and R ₃ is
An alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, or a phenyl group, or F, Cl, Br,
It represents a group represented by I or CN and CF ₃ , which may be the same or different from each other. )), A liquid crystalline polyurethane represented by the formula [I] is reacted with a diisocyanate represented by the formula (III):
-Hydroxyalkyleneoxy) biphenyl and 2,5-toluene diisocyanate are reacted to produce a liquid crystalline polyurethane represented by the formula [II].

The diol component used in the present invention has the formula [II
I] is a bis (ω-hydroxyalkyleneoxy) biphenyl represented by 4,4′-biphenol and ω-bromo-1
-A compound obtained by a reaction with a hydroxyalkane or the like. The compound represented by the formula [III] is specifically a compound wherein m of the methylene chain is 2 to 20,
4'-bis (ω-hydroxyethyloxy) biphenyl,
4,4'-bis (ω-hydroxypropyloxy) biphenyl, 4,4'-bis (ω-hydroxybutyloxy) biphenyl, 4,4'-bis (ω-hydroxypentyloxy) biphenyl, 4,4'- Bis (ω-hydroxyhexyloxy)
Biphenyl, 4,4'-bis (ω-hydroxyheptyloxy) biphenyl, 4,4'-bis (ω-hydroxyoctyloxy) biphenyl, 4,4'-bis (ω-hydroxynonyloxy) biphenyl, 4,4 '-Bis (ω-hydroxydecyloxy) biphenyl, 4,4'-bis (ω-hydroxyundecyloxy) biphenyl, 4,4'-bis (ω-hydroxydodecyloxy) biphenyl, 4,4'-bis ( ω-hydroxytridecyloxy) biphenyl, 4,4′-bis (ω
-Hydroxytetradecyloxy) biphenyl, 4,4'-
Bis (ω-hydroxypentadecyloxy) biphenyl, 4,4'-bis (ω-hydroxyhexadecyloxy)
Biphenyl, 4,4'-bis (ω-hydroxyheptadecyloxy) biphenyl, 4,4'-bis (ω-hydroxyoctadecyloxy) biphenyl, 4,4'-bis (ω-hydroxynonadecyloxy) biphenyl, 4 , 4'-bis (ω-
(Hydroxyeicosyloxy) biphenyl and the like. Since the melting point of 4,4′-bis (ω-hydroxyalkyloxy) biphenyls tends to decrease with an increase in the number of methylene chains, a diol having m of 2 to 15 is practically used as a liquid crystal polyurethane. It is preferably used as a raw material. It should be noted that the bis (ω-
The hydroxyalkyleneoxy) biphenyl is not necessarily reacted with only one kind, and two or more kinds may be reacted as needed. Further, an unsubstituted biphenyl group of the compound represented by the formula (III) has -CH ₃ group, -OCH ₃
A method of introducing a group, halogen or the like to lower the melting point of the target polymer can be considered, but the present inventors aim at the purpose by changing the number of methylene chains of the compound represented by the formula (III). Could be achieved. These are general phenomena observed also in thermotropic polyester and the like.

Further, the diisocyanate represented by the formula [IV] and a substituted product thereof are compounds which easily have a high orientation from the viewpoint of a three-dimensional structure, and are compounds which can impart high functionality such as heat resistance. Further, specific examples of the diisocyanate compound represented by the formula (IV) include 2-methyl
-1,4-phenylene diisocyanate, 2-ethyl-1,4-
Phenylene diisocyanate, 2-trifluoromethyl-1,
4-phenylenediisocyanate, 2,5-dimethyl-1,4-
Phenylene diisocyanate, 2,6-dimethyl-1,4-phenylene diisocyanate, 2,6-diethyl-1,4-phenylene diisocyanate, 2-methyl-6-bromo-1,4-
Phenylene diisocyanate, 2,5-dichloro-1,4-phenylene diisocyanate, 2,5-dimethoxy-1,4-phenylene diisocyanate, 2,5-diethoxy-1,4-phenylene diisocyanate, There are 2,6-naphthylene diisocyanate and the like. Particularly preferably, 2-methyl-1,4-phenylene diisocyanate (sometimes referred to as 2,5-toluene diisocyanate; hereinafter abbreviated as 2,5-TDI)
It is. These compounds are described in Ann., 562, 75 (1948), J. App.
l. Polym. Sci., 8, 533 (1964) and Industrial Chemistry, 68, 315 (19
It can be produced according to the method described in 65).

As a means for solving the above-mentioned problems of the liquid crystal polyurethane, the present inventors have proposed formulas (III) and (IV).
The compound represented by formula (1) is subjected to a polyaddition reaction, thereby enabling the synthesis of a polyurethane exhibiting liquid crystallinity even in a polymer region. As a method for synthesizing the high-molecular liquid crystal polyurethane of the present invention, the diisocyanate component represented by the formula [IV] and the diol component represented by the formula [III] are used in a ratio of 0.8: 1 to
At a ratio corresponding to an NCO / OH equivalent ratio of 1.2: 1, preferably
The reaction is carried out in a proportion corresponding to an NCO / OH equivalent ratio of 0.9: 1 to 1.1: 1, more preferably using an equivalent amount of starting material.
However, it is not limited to these. In the case of the polyaddition reaction, if necessary, a general urethanization catalyst such as dibutyltin dilaurate can be added.
Further, the polymerization reaction is preferably performed in the presence of a suitable solvent, for example, a polar solvent such as dimethylformamide, dimethylacetamide, N-methylpyrrolidone, tetramethylurea, anisole, dioxane, or a mixture of these solvents. The reaction temperature is 20 to 200 ° C, preferably 6
0-160 ° C. The reaction is usually completed in about 4 to 24 hours.

After completion of the reaction, the reaction product is cooled, and then the reaction is stopped by adding a ketone such as acetone, an ether such as diethyl ether, or a diluting solvent such as methanol, and the reaction product is precipitated. Then, this is collected and separated to obtain a desired liquid crystal polyurethane. The liquid crystal polyurethane is separated by a purification method such as a reprecipitation method or a column separation to separate unreacted substances and the like. Thereafter, the polymer liquid crystal polyurethane of the present invention is obtained by drying. The intrinsic viscosity [η] of the polyurethane thus obtained is about 0.4 to 3.
It is in the range of 0 dl / g.

Next, for the purpose of grasping the physical properties of the polyurethane, various studies were conducted on the polymer synthesized according to the above-mentioned method by wide-angle X-ray diffraction, differential scanning calorimetry and the like. As a result, once the polymer synthesized according to the method described above was made into an isotropic fluid and allowed to cool to a solid state, and then subjected to wide-angle X-ray diffraction at room temperature, a clear peak was observed. The polymer was found to be quite crystalline. In addition, as a result of performing differential scanning calorimetry (hereinafter abbreviated as DSC), all the polymers showed an endothermic peak (abbreviated as _Tm ) corresponding to melting and a transition to an isotropic fluid phase during the heating process. Endothermic peak (abbreviated as T _i ), and an exothermic peak during crystallization from the isotropic flow state in the temperature decreasing process. Of these transition states, melting and endothermic phenomena can also be observed with a polarizing microscope.
From these results, all polymers show mesophases,
It became clear that it was a thermotropic liquid crystal polyurethane. It is also surprising that the liquid crystal polyurethane of the present invention has an extremely high intrinsic viscosity [η] of 0.4 to 2.3 dl / g.

[0017]

EXAMPLES The present invention will be described more specifically with reference examples and examples. However, the present invention is not limited to these specific examples. REFERENCE EXAMPLE 1 Production of 2,5-toluene diisocyanate (hereinafter abbreviated as 2,5-TDI) Four 2 l of 122.2 g (1.00 mol) of 2,5-toluenediamine, 450 g of isoamyl acetate, and 1800 g of orthodichlorobenzene were prepared. Put in a mouth flask and stir, 10 ℃ ~ 30
In a temperature range of ℃, hydrogen chloride gas at a rate of 430 ml / min,
Blowing was continued for 2 hours to complete the salt formation reaction. This salt formation reaction proceeded very smoothly without generating agglomerates of hydrochloride particles, and a slurry of uniform fine particles was obtained. After completion of the salt formation reaction, the temperature in the flask was raised from 25 ° C to 16 ° C.
While the temperature was raised to 0 ° C. in about 1 hour, phosgene was gradually blown in from 80 ° C. to start the phosgenation reaction. While adjusting the internal temperature to 155 to 160 ° C, blow phosgene 5
It continued for 6 hours at a rate of 0-60 g / h. The phosgene gas used was about 1.7 times the theoretical amount. Thereafter, nitrogen gas was blown into the reaction solution in the flask at a rate of 1.3 l / min for 80 minutes to perform degassing. During this time, the liquid temperature was 160 ± 1 ° C. The degassed reaction solution was cooled and then filtered to remove insoluble components. After desolvation of this filtrate, under reduced pressure
By rectification, 97.8 g of a 120-122 ° C / 4 Torr fraction was obtained. The obtained fraction is analyzed by elemental analysis, mass spectrometry, infrared spectrum,
It was confirmed to be 2,5-TDI from the results of nuclear magnetic resonance spectrum and the like.

Reference Example 2 Synthesis of 4,4'-bis (ω-hydroxyalkyleneoxy) biphenyl 4,4'-bis (ω-ω) having 2, 3, 5, 6, 8, 11, and 12 methylene groups (Hydroxyalkyleneoxy) biphenyl (DHB, DHPRB, DH respectively)
PEB, DHHB, DHOB, DHUB and DHDB
Was abbreviated as described in Reaction Scheme (a) (Chemical Formula 11).

[0019]

Embedded image DHOB will be described as a typical synthesis example. Sodium hydroxide (5.6 g, 0.140 mol) in ethanol (80 ml)
Dissolved in 4,4'-biphenol (6.5 g, 0.035 mo
l) was added with stirring. After refluxing for 1 hour, 8-bromo-1-octanol (29.3 g, 0.140 m
ol) was slowly added dropwise and the reaction mixture was refluxed with stirring for 24 hours. After completion of the reaction, the content was cooled and put into water to form a precipitate, and the precipitate was filtered and washed with water. The crude product was purified by recrystallization three times from isopropanol for DHB, DHPRB and DHPEB and from a mixture of ethanol and DMF (3: 1) for DHHB, DHOB, DHUB and DHDB. Table 1 shows the synthesis results.
The results are shown in (Table 1).

[0020]

[Table 1] Reference Example 3 Synthesis of 4,4′-bis (4-hydroxybutyleneoxy) biphenyl (DHBB) 4,4′-bis (4-hydroxybutyleneoxy) biphenyl (DHBB) was prepared by converting the hydroxyl group of 4-chloro-1-butanol. Protected and synthesized by the route shown in Reaction formulas (b) to (d).

[0021]

Embedded image 3,4-Dihydro-2-pyran (63 g, 0.78 mol) was added to a mixture of 4-chloro-1-butanol (50 g, 0.46 mol) and concentrated hydrochloric acid (0.5 ml) cooled to 0 ° C. Thereafter, the mixture was stirred at room temperature for 20 hours. Sodium carbonate (5 g) was added to the reaction solution, and the mixture was neutralized and filtered. The reaction product was distilled under reduced pressure (bp
(108-109 ° C / 8 Torr). The yield is 63% (56.0
g). 4,4 '-(Tetrahydro-2-pyranyloxybutyloxy) biphenyl is 4- (tetrahydro-2-pyranyloxy) -1-chlorobutane (56.06 g, 0.29 mol)
Using 4,4'-biphenyldiol (27.1 g, 0.145 mol), it was carried out in the same manner as in the synthesis of DHOB. 45% yield
(32.3 g). This product (32.0 g, 0.064 mol) was dissolved in hot methanol, concentrated sulfuric acid (5 ml) was added, and the mixture was stirred under reflux for 0.5 hour. The reaction was cooled, the precipitate was filtered, and the resulting crude product was washed with ethanol followed by water and finally purified by recrystallization from isopropanol.

Example 1 In a 100 ml three-necked round-bottomed flask equipped with a reflux tube, 1.258 g (4.593 mmol) of 4,4'-bis (ω-hydroxyethoxy) biphenyl (abbreviated as DHB) and 2,5 -0.8 g (4.593 mmol) of toluene diisocyanate (2,5-TDI) and 15 ml of anhydrous DMF as a solvent were added under nitrogen atmosphere at 80 ° C.
A time reaction was performed. After the reaction, 30 ml of DMF was added to the product, which was poured into 150 ml of methanol to obtain a precipitate. The resulting precipitate is thoroughly washed with methanol and then
It dried under reduced pressure for 24 hours. The structure of the obtained polymer is ¹ H-N
As a result of analysis by MR and infrared spectra, 2,5-TDI and DHB
Has a chemical structure as a reaction product with. The thermal properties and liquid crystallinity were examined by DSC and polarizing microscope. As a result, the melting point (hereinafter abbreviated as _Tm ) of the polymer and the transition point to the isotropic fluid phase (hereinafter T
_i ) at 274 ° C. and 284 ° C., respectively. In the cooling process, an exothermic peak due to crystallization was also measured, and T _i and T _m were 230 ° C and 22 ° C, respectively.
The temperature dropped to 0 ° C and a supercooling phenomenon of about 50 ° C was observed. Also, once the isotropic fluid was allowed to cool to a solid state and then measured at room temperature by wide-angle X-ray diffraction, 2θ = 17.8 °, 19.5 °, 23.8 ° clear diffraction The peak was confirmed, indicating that the liquid crystal polyurethane was considerably rich in crystallinity.

Examples 2 to 8 In the same manner as in Example 1, 2,5-TDI and 4,4'-bis (ω-
(Hydroxyalkyleneoxy) biphenyl derivative. Table 2 (Table 2) and Table 3 (Table 3) show the synthesis conditions and various physical properties of the obtained polyurethane as a high-molecular liquid crystal polyurethane, respectively.

[0024]

[Table 2]

[0025]

[Table 3]

[0026]

The polyurethane obtained according to the present invention is a polyurethane having liquid crystallinity containing a mesogen having good orientation. From this, in addition to the polyurethane resin modifying material, alone or as a composition, film, fiber,
It is easy to mold and process into various forms such as thin films.
In addition, a wide range of modification is possible by applying a general modification method for a polymer substance such as copolymerization, blending with another component, or alloying.

Claims (4)

(57) [Claims] [Claim 1] The following general formula [I] (Chemical formula 1) (Wherein A is the following structural formula (Chemical Formula 2) Wherein at least one of R ₁ , R ₂ and R ₃ is
An alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, or a phenyl group, or F, Cl, Br,
It represents a group represented by I or CN and CF ₃ , which may be the same or different from each other. m represents an integer of 2 to 20. Polyurethane exhibiting liquid crystallinity, comprising a repeating unit represented by ()). 2. The following formula [II] (Chem. 3) (In the formula, m represents an integer of 2 to 20.) A polyurethane having a liquid crystallinity, comprising a repeating unit represented by the following formula: 3. The following formula [III] (Chem. 4) (Wherein m represents an integer of 2 to 20), and bis (ω-hydroxyalkyleneoxy) biphenyl represented by the following formula [IV] OCN-A-NCO [IV] (where A is the following structural formula: (Formula 5) Wherein at least one of R ₁ , R ₂ and R ₃ is
An alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, or a phenyl group, or F, Cl, Br,
It represents a group represented by I or CN and CF ₃ , which may be the same or different from each other. The method for producing a polyurethane having liquid crystallinity according to claim 1, wherein the diisocyanate represented by the formula (1) is reacted. 4. The production of a liquid crystalline polyurethane according to claim 2, wherein bis (ω-hydroxyalkyleneoxy) biphenyl represented by the formula [III] is reacted with 2,5-toluene diisocyanate. Method.