JPH0735437B2 - Polycarbonate - Google Patents

Description

TECHNICAL FIELD The present invention relates to a novel polycarbonate having excellent heat resistance and flame retardancy, and more specifically, it is mainly obtained from an aromatic diol containing a phosphorus atom. The present invention relates to a novel polycarbonate.

(Prior Art) Polycarbonate has been known as a polymer having excellent impact resistance and heat resistance, and is used as an engineering resin in various ways. Generally, polycarbonate resins are roughly classified into aliphatic polycarbonate resins, aliphatic-aromatic polycarbonate resins, and aromatic polycarbonate resins. Among them, polycarbonate resins derived from bisphenol A (Mitsubishi Gas Chemical Co., Ltd., trade name “UPILON”, Mitsubishi Kasei, product name "Novarex", Teijin Kasei, product name "Panlite", etc.) are industrially produced.

In recent years, from the viewpoint of economic efficiency, the wall thickness of molded products has tended to be thin, and therefore workability is required to be improved. Therefore, a polycarbonate resin with improved fluidity (Mitsubishi Gas Chemical Co., Ltd., trade name "UPILON H300" used for molding thin molded products
0 ”) has been proposed and is currently on the market.

Further, in recent years, there has been an increasing demand for flame retardancy of fibers and engineering resins from the viewpoint of fire prevention, and in polycarbonate resins, polycarbonate resins filled with glass fibers to impart flame retardancy (for example, Mitsubishi Gas Chemical Co., Ltd., trade name " Iupilon GS2010M ”) was proposed and is now on the market.

(Problems to be Solved by the Invention) However, in the above-mentioned conventional techniques, not only the improvement of melt processability is still insufficient, but also the polycarbonate resin has a low molecular weight in order to improve the fluidity. However, there is a drawback that impact resistance and stress crack resistance are reduced.

Further, in a polycarbonate resin filled with glass fibers to impart flame retardancy, there is a drawback that the melt processability is deteriorated by filling glass fibers even though flame retardancy can be imparted.

Therefore, the main object of the present invention is to provide a novel polycarbonate resin having excellent melt processability, good heat resistance, and high flame retardancy.

(Means for Solving Problems) The inventors of the present invention have earnestly studied a new polycarbonate resin having no problems as described above, and as a result, found that a phosphorus-containing polycarbonate resin having a specific structural unit has extremely excellent properties. They have found the present invention and reached the present invention.

That is, the subject matter of the present invention is a polycarbonate having an intrinsic viscosity of 0.5 or more, which comprises a structural unit represented by the following structural formula (I), and preferably, an anisotropic molten phase is formed at a temperature of 400 ° C. or less. The gist is a thermotropic liquid crystalline polycarbonate that can be used.

(In the formula, Ar represents a trivalent aromatic group. However, even if the hydrogen atom of the aromatic ring is substituted with a halogen atom, a lower alkyl group having 1 to 20 carbon atoms, an aryl group, an alkoxy group or an aryloxy group. Good.) As Ar in the structural formula (I), a benzene ring and a naphthalene ring are preferable.

The thermotropic liquid crystallinity referred to in the present invention refers to the property that the molecules of the polycarbonate are regularly arranged in one direction in the melt phase to form a liquid crystal called a nematic phase. It can be confirmed by technology.

As the polycarbonate of the present invention, a polycarbonate that can form an anisotropic melt phase that is extremely easy to process at 400 ° C. or less, preferably about 300 ° C. is extremely suitable.

The method for producing the polycarbonate of the present invention is not particularly limited. For example, (1) a bulk polymerization method of a phosphorus-containing aromatic diol and a carbonic acid ester, or (2) a phosphorus-containing aromatic diol and phosgene Although it can be produced by the phosgene method of polymerizing in an alkaline solution, the method (1) is preferable because the phosphorus-containing aromatic diol may have poor alkali resistance.

As the phosphorus-containing aromatic diol used for producing the polycarbonate of the present invention, specifically, the following structural formula (II),
Examples thereof include organic phosphorus compounds such as (III) and (IV) (PHQ, 1,4-PHQ, 2,6-PNQ, respectively).

The carbonic acid ester used for producing the polycarbonate of the present invention includes diphenyl carbonate, dimethyl carbonate,
Diethyl carbonate and the like can be mentioned.

The polycarbonate of the present invention has an intrinsic viscosity [η] of 0.5 or more, preferably 0.5 to 5.0, optimally 0.5 to 2.0,
When [η] is less than 0.5, it is difficult to obtain practical physical properties as a molded product.

The ratio of the phosphorus-containing aromatic diol to the carbonic acid ester used in the production of the polycarbonate of the present invention is usually 30/70 to 50/50, and optimally 40/60 to 50/50 in terms of equivalent ratio.

The temperature conditions and reaction time for producing the polycarbonate of the present invention are as follows. First, in a transesterification reaction between a phosphorus-containing aromatic diol and a carbonic acid ester, usually in a nitrogen atmosphere at 100 to 200 ° C. for 0.5 to 4 hours, preferably 120 to 190 ° C for 1 to 3 hours, optimally 120 to 170 ° C for 1.5 to 2 hours. Then, the pressure inside the reaction system was reduced to 100 to 50 mmHg, and the temperature was raised to 2
The reaction is carried out at 30 to 260 ° C, preferably 250 to 260 ° C for 1 to 6 hours, preferably 2 to 4 hours. Furthermore, the condensation reaction is carried out under reduced pressure (usually 0.01 to 10 mmHg) at 280 to 350 ° C for 1 to 8 hours, preferably 290 to 340 ° C for 2 to 6 hours, optimally 300 to 330 ° C.
2 to 4 hours.

Usually, a catalyst is used in the reaction, but various metal compounds are used as the catalyst for obtaining the polycarbonate of the present invention. As the metal compound, compounds such as antimony, titanium, germanium, tin, zinc, aluminum, magnesium, calcium, manganese, sodium and cobalt are used. The catalyst is added in an amount of 1 mol of polycarbonate constitutional unit,
Usually 1 × 10 ⁻⁵ to 1 × 10 ⁻² mol, preferably 5 × 10 ^{−5 to} 5
× 10 ^-3 mol, optimally 1 × 10 ^-4 to 1 × 10 ^-3 mol is used.

(Examples) Hereinafter, the present invention will be described in more detail with reference to Examples.

In addition, the intrinsic viscosity [η] of the polymer in the examples was determined from the solution viscosity measured at 20 ° C. in a mixed solvent such as phenol-ethane tetrachloride by weight. The softening point was measured with a softening point measuring device (AMPI type manufactured by Yanagimoto Seisakusho) at a heating rate of 2 ° C / min.
In addition, the flame retardancy is based on UL94 standard (HB, V-2, V
-1, V-0) and the limiting oxygen index (LOI) according to JIS K 7201 standard. The impact strength was evaluated by Izod impact strength (notched) after forming an impact test piece specified in ASTM D256. The melt viscosity was measured by using a Koka type flow tester (Shimadzu FT-500 type) under the conditions of temperature 280 ° C, nozzle 1mmφ × 10mmL, pressure 40kg / cm ² and used as a measure of melt processability. On the other hand, the polycarbonate of the present invention was identified by infrared absorption spectrum and elemental analysis. Also, thermotropic liquid crystal property is with hot stage
Confirmed with a Leitz polarization microscope.

Example 1 A reactor was charged with PHQ and diphenyl carbonate at an equivalent ratio of 45/55, and zinc acetate as a catalyst was added at 4 × 10 ⁻⁴ mol per 1 mol of repeating unit of polycarbonate, and the mixture was heated at 160 ° C. under a nitrogen atmosphere at 160 ° C. The ester conversion reaction was carried out for 2 hours. Then, the pressure in the reaction system was reduced to 100 to 50 mmHg, the temperature was raised to 250 ° C. over 1 hour, and the reaction product was reacted for 3 hours to distill the produced phenol. Furthermore, the temperature is 300 ℃ over 1 hour.
The pressure was gradually reduced to 1 mmHg and the reaction was performed for 3 hours. The obtained polymer had an [η] of 0.72, a softening point of 183 ° C., UL94 standard V-0 grade, a limiting oxygen index of 60, and was excellent in color tone and transparency.

When this polymer was analyzed by infrared absorption spectrum and elemental analysis, the following results were obtained, and it was confirmed that the polymer was a polycarbonate having the following repeating units.

That is, in the infrared absorption spectrum, the absorption based on C = O of the aromatic carboxylic acid ester was 1770 κ and 720
Absorption of para-substituted aromatics was observed at κ and 760κ, and absorption of asymmetric tri-substituted aromatics was observed at 840κ. On the other hand, the elemental analysis results show that C = 64.97% (theoretical value 65.15%), H = 3.21% (theoretical value 3.
17%), P = 8.69% (theoretical value 8.84%). As a result of observation with a Leitz polarization microscope with a hot stage, it was confirmed that the obtained polymer was thermotropic liquid crystalline polycarbonate.

Example 2 A reactor was charged with PHQ and dimethyl carbonate in an equivalent ratio of 45/55, and zinc acetate as a catalyst was added at 4 × 10 ⁻⁴ mol to 1 mol of repeating units of polycarbonate, and 120 ° C. under a nitrogen atmosphere. Transesterification was carried out for 2 hours. Then, the pressure inside the reaction system was reduced to 100 to 50 mmHg, and the temperature was changed for 1 hour.
The temperature was set to 50 ° C., and the phenol produced by reacting for 3 hours was distilled off. Further, the temperature is raised to 290 ° C over 1 hour,
The pressure was gradually reduced to 1 mmHg and the reaction was performed for 3 hours. The obtained polymer had an [η] of 0.69, a softening point of 181 ° C, UL94 standard V-
It was a polymer with 0 grade and a limiting oxygen index of 58. The results of infrared absorption spectrum, elemental analysis, and Leitz polarization microscope observation were the same as in Example 1, and it was confirmed that the substance was a thermotropic liquid crystalline polycarbonate.

As a result of carrying out in the same manner as in Example 1 except that 1,4-PNQ or 2,6-PNQ was used instead of PHQ in Examples 3 and 4, respectively, the obtained polymer had [η] in Example 3. 0.70, softening point 188 ℃, UL9
4 standard V-0 class, limiting oxygen index 62, in Example 4 [η] 0.98, softening point 186 ° C, UL94 standard V-0 class, limiting oxygen index 60, all excellent in color tone and transparency. . When the polymer of Example 3 was analyzed by infrared absorption spectrum and elemental analysis, the following results were obtained, and it was confirmed that the polymer had the following repeating unit.

That is, in the infrared absorption spectrum, the absorption based on C = 0 of the aromatic carboxylic acid ester at 1770 κ was 746.
Absorption of para-substituted aromatics was observed at κ and 763κ, and absorption at 1630κ was based on the naphthalene ring. On the other hand, in the elemental analysis results, C = 69.51% (theoretical value 69.02%), H = 3.18% (theoretical value 3.
27%) and P = 7.69% (theoretical value 7.74%). As a result of observation with a Leitz polarization microscope with a hot stage, it was confirmed that the obtained polymer was thermotropic liquid crystalline polycarbonate. In addition, the polymer of Example 4 was also able to obtain almost the same result.

Example 5 The same procedure as in Example 1 was carried out except that the equivalence ratio of PHQ to diphenyl carbonate was 30/70. As a result, the polymer obtained had [η].
0.67, softening point 183 ℃, UL94 standard V-0 class, limiting oxygen index 59
It was a thermotropic liquid crystalline polycarbonate with excellent color tone and transparency.

Example 6 Instead of using PHQ alone as the phosphorus-containing aromatic diol,
Example 1 was repeated except that PHQ and 1,4-PNQ were used in a molar ratio of 70/30. The obtained polymer was a polycarbonate having a [η] of 0.61, a softening point of 181 ° C., UL94 standard V-0 grade, a color tone with a limiting oxygen index of 54, and excellent transparency at 400 ° C. and having no thermotropic liquid crystallinity.

Comparative Examples 1 and 2, except that the equivalent ratio of PHQ to diphenyl carbonate was changed to 10/90 or 80/20, the results were the same as in Example 1, and the obtained polymer had [η] of 0.31 and 0.27, respectively. ， It was very brittle.

(Effect of the invention) The polycarbonate of the present invention has excellent moldability and heat resistance,
Moreover, it is a heat-resistant polymer with a high degree of flame retardancy and is extremely useful as a material for film and molding.

Claims (2)

[Claims] 1. A polycarbonate having an intrinsic viscosity of 0.50 or more, which comprises a structural unit represented by the following structural formula (I). (In the formula, Ar represents a trivalent aromatic group. However, even if the hydrogen atom of the aromatic ring is substituted with a halogen atom, a lower alkyl group having 1 to 20 carbon atoms, an aryl group, an alkoxy group or an aryloxy group. Good.) 2. The polycarbonate according to claim 1, which has a thermotropic liquid crystallinity capable of forming an anisotropic melt phase at a temperature of 400 ° C. or lower.