JPS6143446B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing polyarylate molded articles having excellent mechanical properties, and more particularly to a method for producing polyarylate fibers having increased strength and Young's modulus through simplified heat treatment. Conventionally, as described later, for example, Comparative Example 1
For example, by melt-molding a polyarylate having a specific composition as shown by the authors, a fiber or sheet with a high initial Young's modulus can be obtained, and by further heat treatment for a long time, it can be made to have high strength and high strength. It is known to obtain a molded product with a Young's modulus (Japanese Patent Application Laid-Open Nos. 50-158695, 1973-157619).
(see publication). However, in order to obtain high-strength polyarylate molded products, in vacuum or in an inert medium,
It is extremely disadvantageous economically as it requires a long heat treatment including stepwise temperature increases at a high temperature close to the softening temperature of the polymer, and in order to avoid this long heat treatment, the heat treatment should be completed in a short time. If this is the case, problems such as (1) the resulting molded product will have insufficient strength and (2) fusion will occur between the molded products will occur. The inventors of the present invention have conducted intensive research to eliminate the above-mentioned drawbacks and obtain a polyarylate molded product with excellent performance under industrially advantageous conditions. The present invention has been achieved based on the discovery that not only is fusion less likely to occur during heat treatment, but also that fibers with high strength and Young's modulus can be obtained by heat treatment at a relatively low temperature and for a short time. That is, the present invention has the following formulas (A), (B) and (C) Substantially composed of p-oxybenzoic acid residue (A), hydroquinone residue (B) and isophthalic acid residue (C) represented by (A)/(B) (molar ratio) 50/50 to 80／
20, (B)/(C) (molar ratio) is 1, the polymer flow initiation temperature is 280℃ or higher, and the shear rate at 350℃
A polyarylate having an apparent melt viscosity of 500 poise or less at 1000 sec ^-1 and an intrinsic viscosity of 0.5 or more is melt-spun, and the resulting fiber is then heated at 180°C.
This is a method for producing polyarylate fibers having increased strength and Young's modulus, which is characterized by heat treatment at a temperature above. In the present invention, polyarylates have the above formulas (A) and (B).
and (C), that is, a p-oxybenzoic acid residue, a hydroquinone residue, and an isophthalic acid residue, and the (A)/(B) (molar ratio) is
50/50 to 80/20 and (B)/(C) (molar ratio) is 1/
1. Preferably (A)/(B) (molar ratio) is 50/50 to
The ratio is 70/30 and (B)/(C) (molar ratio) is 1/1. In the present invention, the polyarylate to be subjected to the melt molding is prepared by combining p-hydroxybenzoic acid and/or its derivatives with hydroquinone and/or its derivatives, isophthalic acid and/or its derivatives, and heating the polymer at 340°C or lower until the intrinsic viscosity of the polymer reaches 0.5 or higher. It is produced by reacting at high temperatures. Here, the p-hydroxybenzoic acid derivative, the hydroquinone derivative, and the isophthalic acid derivative are represented by the following formulas (1), (2), and (3), respectively. In the above formula, R ₁ , R ₃ , and R ₄ are each independently selected from the group consisting of a lower alkanoyl group having 7 or more carbon atoms and a benzoyl group, and R ₂ , R ₅ , and R ₆ have 6 to 12 carbon atoms.
each independently selected from the group consisting of an aryl group and a lower alkyl group having 6 or less carbon atoms. In the present invention, specific examples of the compounds represented by formulas (1), (2), and (3) are p-formyloxybenzoic acid,
p-acetoxybenzoic acid, p-propoxybenzoic acid, p-benzoyloxybenzoic acid, phenyl p-oxybenzoate, tolyl p-oxybenzoate,
p-Butylphenyl p-oxybenzoate, β-naphthyl p-oxybenzoate, methyl p-oxybenzoate, ethyl p-oxybenzoate, phenyl p-acetoxybenzoate, 1,4-diacetoxybenzene, 1,4 -dipropoxybenzene, 1.4
- Dibenzoyloxybenzene, diphenyl isophthalate, ditolyl isophthalate, diphenyl isophthalate, diphenyl isophthalate, diphenyl isophthalate, diα-naphthyl isophthalate, dimethyl isophthalate, diethyl isophthalate, dipropyl isophthalate, etc. I can do it. In the present invention, a preferred method for producing polyarylate is (1) heating and polymerizing phenyl p-oxybenzoate, hydroquinone, and diphenyl isophthalate (2) polymerizing p-acetoxybenzoic acid, 1,4-diacetoxybenzene, and isophthalic acid. Heat polymerization reaction (3) After adding an aryl carbonate such as diphenyl carbonate to p-oxybenzoic acid and isophthalic acid and carrying out an esterification reaction by heating, (p-oxybenzoic acid and isophthalic acid are each substantially (4) A reaction product of p-oxybenzoic acid and an aryl carbonate such as diphenyl carbonate or p- Add phenyl oxybenzoate and polymerize by heating. (5) Add p-oxybenzoic acid and an aryl carbonate such as diphenyl carbonate to an esterified product of isophthalic acid and phenol and/or hydroquinone, heat to perform an esterification reaction, and then heat polymerize. be. Examples of the aryl carbonate include diphenyl carbonate, ditolyl carbonate, bis p-hydroxyphenyl carbonate,
Examples include monocarbonates such as phenyltolyl carbonate and phenyl p-hydroxyphenyl carbonate, as well as polycarbonates such as polyphenylene carbonate. In the present invention, p-oxybenzoic acid phenyl,
Aryl esters of p-oxybenzoic acid or isophthalic acid such as diphenyl isophthalate can be produced by conventionally known methods. For phenyl p-oxybenzoate, (a) React p-oxybenzoic acid and diphenyl carbonate (b) React p-oxybenzoic acid and phenyl acetate in the presence of hydrochloric acid (c) p-acetoxybenzoic acid It can be obtained by methods such as (d) reacting acid and phenol with methyl p-oxybenzoate and phenol using a transesterification catalyst, among which the raw material p obtained by method (a) - Particular preference is given to using oxybenzoic acid. On the other hand, phenyl isophthalate is obtained by (e) esterification reaction between isophthalic acid and phenol (f) reaction between isophthalic acid and phenyl acetate in the presence of hydrochloric acid (g) titanium-based esterification reaction between dimethyl isophthalate and phenyl acetate. Although it can be obtained by a method such as reaction using a catalyst, the method (e) is particularly preferred. In the above-mentioned esterification reaction between isophthalic acid and phenol and/or hydroquinone, the hydroxyl group of phenol and/or hydroquinone is 1 times or more in mole relative to the carboxyl group of isophthalic acid, preferably
1.1 to 4 times the mole, particularly preferably 1.2 to 2 times the mole, 230 to 400°C, preferably 240 to
The reaction is carried out while heating to 360°C and distilling water produced as a result of the esterification reaction out of the reaction system. The esterification reaction usually takes 1 to 12 hours, and if necessary ~10 hours.
It can be carried out under pressure of Kg/cm ² . At this time, the esterification rate is 50% or more, preferably 70% or more, particularly preferably 85% or more. Here, the esterification rate is determined from the following formula. Esterification reaction rate (%) = Amount of ester groups newly generated in the reaction system by the esterification reaction (equivalent) / Amount of free carboxyl groups initially present in the reaction system (equivalent) x 100 In the esterification reaction, the catalyst is not necessarily Preferably, but not necessarily, a catalyst is used. Such catalysts include titanium tetrabutoxide, titanyl oxalate, stannous acetate, stannous chloride, dibutyltin oxide, lead oxide, antimony trioxide, antimony pentoxide, bismuth trioxide, cerium acetate, lanthanum oxide, lithium oxide, Examples include titanium such as sodium metal, potassium benzoate, zinc carbonate, metals such as tin, lead, antimony bismuth, cerium, lanthanum, lithium, sodium, potassium, zinc, and compounds containing these metals. The amount of these catalysts used is 0.005 to 0.5 mol%, preferably 0.01 to 0.1 mol%, based on the dicarboxylic acid. In the polyarylate production methods (3), (4) and (5) of the present invention, oxybenzoic acid is reacted with an aryl carbonate. When isophthalic acid or an esterified product of isophthalic acid containing a free carboxyl group is present during this reaction, the free carboxyl group reacts with the aryl carbonate. Therefore, the amount of aryl carbonate to be added is 0.8 to 1.1 times the mole of carbonate bonds contained in the aryl carbonate per the total amount of free carboxyl groups contained in the reaction system containing oxybenzoic acid.
Preferably, the amount should be approximately 1 molar. The reaction between the aryl carbonate and oxybenzoic acid, a mixture of oxybenzoic acid and isophthalic acid, or an ester thereof is carried out at a temperature of 200 to 300°C, preferably 220 to 260°C, and carbon dioxide gas is generated by the reaction. Continue until the process is substantially completed. This reaction is suitable for 1 to 6 hours and is preferably catalyzed. As this catalyst, the same catalyst as used in the esterification reaction can be used in a range of 0.005 to 0.5 mol % based on the carboxylic acid component as in the case of the esterification reaction. The polymerization reaction of polyarylate is carried out using the same catalyst as the esterification catalyst, particularly preferably a soluble tin catalyst, at a temperature range of 250 to 340°C, preferably 290 to 320°C. It is particularly preferable to carry out the initial stage of polymerization in a molten state.
In (1), (3), (4), and (5), phenol and/or hydroquinone produced in the polymerization reaction is used, and in polyarylate production method (2), lower aliphatic carboxylic acid or aromatic carboxylic acid is used. Remove from the reaction system. Therefore, the reaction pressure may be around normal pressure at the beginning of the polycondensation reaction, but at the final stage it may be around 100 mm.
It is preferably below Hg (50 to 0.01 mmHg). According to the above-described preparation, oxybenzoic acid and/or its derivatives, isophthalic acid and/or its derivatives are not significantly lost by decomposition. On the other hand, a portion of hydroquinone and/or its derivatives is distilled out of the polymerization reaction system during polymerization. Therefore, the charging ratio of raw materials in the production of polyarylate can be expressed by the following formula. 0.5≦(NA/NA+NC)≦0.8 1≦NB/NC [In the formula, NA, NB, and NC are respectively oxybenzoic acid and/or its derivatives (A) hydroquinone and/or its derivatives (B) isophthalic acid and (or) indicates the number of moles of its derivative (C). ] Here, the particularly preferable ratio of NB to NC is:
Although it varies depending on the manufacturing method of polyarylate, in the above manufacturing method (2), NB/NC≒1, in the above manufacturing methods (1) and (3), 1≦NB/NC≦1.2, and in the above manufacturing methods (4) and (5), phenol and When hydroquinone is used in the esterification reaction, 1≦NB/NC≦1.2 When only hydroquinone is used in the esterification reaction in the above production methods (4) and (5), 1≦NB/NC≦2. If the amount of NB used relative to NC is too small or too large, it will be difficult to obtain a high polymer. As the method for producing the polyarylate of the present invention, the above-mentioned production methods (1), (3), (4), and (5) are preferable. Manufacturing method (1), (3), (4)
,
This is because in the case of (5), highly strong polyarylate fibers can be obtained with shorter heat treatment. Polymers obtained by the above methods exhibit various flow characteristics depending on the polymerization conditions, but the flow initiation temperature varies.
It has the property that the apparent melt viscosity at a shear rate of 1000 sec ^-1 is 500 poise or less at a temperature of 280 °C or higher, and preferably a flow start temperature of 285 °C or higher and an apparent melt viscosity of 400 poise or lower at a shear rate of 1000 sec ^-1 . It has a property of over 100 poise. Having this property is preferable because the polymer can be heat-treated after spinning to yield high-strength polyarylate fibers. Regarding the influence of polymerization conditions on the flow characteristics of polyarylate, the influence of polymerization temperature is the most important.If the polymerization temperature is too high (for example, if the temperature exceeds 340℃ when the intrinsic viscosity is less than 0.5, the polymerization temperature will increase even if the intrinsic viscosity is the same. The apparent melt viscosity of the coalesce increases.If the apparent melt viscosity of a polymer is too high, even if the fibers are heat-treated after spinning, it will not be possible to obtain a molded article with sufficiently high strength, and the Young's modulus of the fibers will also be low, which is preferable. The intrinsic viscosity of the polyarylate of the present invention is 0.5 or more, preferably 0.6 or more and 1.5 or less, particularly preferably 0.7 to 1.5.
It is 1.4. If the intrinsic viscosity is too low, the strength of the polyarylate fiber before heat treatment tends to be low and it becomes difficult to handle. On the other hand, if the intrinsic viscosity is too high, the polyarylate fiber will not have good spinnability, which is one of the objectives of the present invention, and It becomes difficult to produce polymers that give high strength fibers upon heat treatment. Regardless of the method described above, a polymer obtained by polymerization for a long time in the presence of a heat medium according to a conventional method, for example, has the same composition as that of the present invention, but has an apparent shear rate of 1000 sec ^-1 at 350°C. The disadvantage is that the melt viscosity is greater than 500 poise, and the fibers obtained from such polymers do not have sufficient strength even after heat treatment. The polyarylate of the present invention can be easily melt-spun using a conventional method, for example, at 300-380°C.
Fibers can be obtained by melt-spinning preferably at a temperature of 320 to 370°C and winding at a draft rate of 5 or more, preferably 10 to 100. The fibers obtained here usually have Young's modulus, strength, and elongation of 180 to 300 g/de, 3 to 6 g/de, and 1 to 3%, respectively.
It is. The polyarylate fibers described above, compared to polyarylate fibers according to the prior art, (1) provide fibers with sufficiently increased strength, Young's modulus, etc. by heat treatment at relatively low temperatures; and (2) have a tendency to fuse during heat treatment. It has the characteristic that it can provide fibers with the above properties with little heat treatment and short heat treatment.When considering commercialization, the biggest obstacle from the viewpoint of production cost was heat treatment (inert media). This makes it possible to greatly simplify the process (medium, high temperature, long time). The polyarylate fiber of the present invention may be heat-treated at normal pressure or in air under vacuum, but preferably in an inert gas such as nitrogen at a temperature of 180°C or higher, preferably 200 to 300°C, particularly in the range of 220 to 280°C. Do it with The heat-treated polyarylate fiber obtained by the present invention has Young's modulus, strength, and elongation of 300 each.
-600g/de, 15-25g/de, 3-6%, and has excellent heat and humidity resistance, so it is useful as a high Young's modulus and high strength fiber when used in industrial applications. In the present invention, the flow start temperature (Ts) is determined by measuring the pore size using a Koka type flow tester (manufactured by Shimadzu Corporation).
The polymer was placed in a heating furnace equipped with a nozzle with a diameter of 0.5 mm and a hole length of 4 mm, and was heated at a rate of about 5 per minute under a pressure of 100 Kg/ ^cm2.
It is measured as the temperature at which the polymer starts to flow out from the nozzle. Further, the shear rate (γa) and the apparent melt viscosity (ηa) were measured using the same Koka type flow tester at a measurement temperature of 350° C., and were calculated using the following formula. γa=4Q/πγ ³ ηa=πPγ ⁴ /8lQ [where Q: discharge rate (cc/sec), γ: capillary radius (cm), P: extrusion pressure (dyne/cm ² ), l: capillary length (cm)] The method of the present invention will be explained below with reference to Examples and Comparative Examples. In addition, the intrinsic viscosity (ηinh) in the examples is for the polymer.
Dissolve 50mg in 10ml of parachlorophenol and heat at 50°C.
The relative viscosity (ηa) was determined using the following formula. ηinh=lnηr/C where C is the polymer concentration (g/de). Moreover, Ta and ηa are measured values defined in the text. Furthermore, parts refer to parts by weight. Example 1 Phenyl p-oxybenzoate 128.4 parts, hydroquinone 46.2 parts, diphenyl isophthalate 127.2 parts
and 0.10 parts of stannous acetate were placed in a polymerization kettle equipped with a stirrer, an inlet and an outlet for nitrogen gas, and heated to 250°C with a gentle flow of nitrogen gas. The temperature was raised to ℃. Next, while raising the temperature to 310°C, the pressure inside the system was gradually reduced to 0.3 mmHg after 30 minutes, and the reaction was continued for an additional 10 minutes. The obtained polymer had an intrinsic viscosity (ηinh) of 0.91, a flow start temperature (Ts) of 304℃,
The apparent melt viscosity at a shear rate of 1000 sec ^-1 is
It was 230 poise. This polymer was extruded through a spinneret having a hole diameter of 0.3 mmφ and 10 holes at a spinning temperature of 350° C. at a rate of 16.0 g/min, and wound at a speed of 450 m/min. The obtained fiber has a single yarn fineness of 31.0 de, strength of 3.5 g/de, and elongation of 1.6.
%, and the initial Young's modulus was 240 g/de. This fiber was heated from 240℃ to 280℃ for 10℃/hr in a nitrogen gas stream.
The heat treatment was performed while increasing the temperature at a rate of . The obtained fiber has no fusion between single yarns, single yarn fineness of 29.8 de, and strength.
The yarn showed physical properties of 21.8 g/de, elongation of 4.1%, and initial Young's modulus of 550 g/de. Example 2 149.8 parts of phenyl p-oxybenzoate, 34.6 parts of hydroquinone, 95.4 parts of diphenyl isophthalate, and 0.10 parts of stannous acetate were reacted under the same conditions as in Example 1. The intrinsic viscosity (η
inh) was 1.01, the flow start temperature (Ts) was 287°C, and the apparent melt viscosity at a shear rate of 1000 sec ^-1 was 320 poise. This polymer was extruded from a spinneret having a hole diameter of 0.3 mmφ and 10 holes at a spinning temperature of 350° C. at a rate of 7.5 g/min and wound at a speed of 200 m/min. The obtained fiber had a single yarn fineness of 33.2 de, strength of 5.2 g/de, elongation of 2.7%,
The initial Young's modulus was 230 g/de. This fiber was heat-treated in a nitrogen gas stream while increasing the temperature to 240°C at a rate of 10°C/hr. The obtained fiber had no fusion between single filaments, single filament fineness of 31.8 de, strength of 17.7 g/de, elongation of 4.7%, and initial Young's modulus of 378 g/de. Comparative example 1 116.2 parts of terephthalic acid, naphthalene-2.6-
64.8 parts of dicarboxylic acid and 228.5 parts of 5-chloro-1,4-diacetoxybenzene were charged into a polymerization kettle together with 1500 parts of partially hydrogenated terphenyl, and the mixture was heated to 270 parts in a nitrogen stream.
℃ for 1 hour, 310℃ for 2 hours, 330℃ for 1 hour,
The intrinsic viscosity obtained by heating polymerization at 350℃ for 2 hours is
1.62, flow start temperature 265℃, shear rate 1000sec ^-1
A polymer with a melt viscosity of 240 poise at 320°C was obtained,
The polymer was spun under the same conditions as in Example 1 except that the spinning temperature was 320°C. The obtained fiber had a single yarn fineness of 29.3 de, a strength of 4.8 g/de, an elongation of 1.3%, and an initial Young's modulus of 440 g/de. This fiber was heat-treated in a nitrogen gas stream while increasing the temperature from 240°C to 320°C at a rate of 10°C/hr. The obtained fiber had a single filament fineness of 28.2 de, strength of 22.3 g/de, elongation of 6.1%, and initial Young's modulus of 400 g/de, but considerable fusion between the single filaments was observed. Example 3 and Comparative Example 2 The untreated fibers obtained in Example 1 and Comparative Example 1 were heat treated in a nitrogen gas stream at a heating rate of 20°C/hr from 220°C. When samples were taken out sequentially at a predetermined temperature, the strength of the obtained fibers (g/d
e) was as shown in the following table.

[Table] Example 4 The unheat-treated fiber obtained in Example 1 was heat-treated for 30 minutes while increasing the temperature from 260°C to 280°C in a nitrogen gas stream. The obtained fiber has a single yarn fineness of 30.0 de and strength.
The yarn showed physical properties of 19.2 g/de, elongation of 4.0%, and initial Young's modulus of 480 g/de. Comparative Example 3 When the unheat-treated fiber obtained in Comparative Example 1 was heat-treated under the same conditions as in Example 4, the obtained fiber had a single yarn fineness of 28.5 de, strength of 8.1 g/de, and elongation of 2.1.
%, and the initial Young's modulus was 460 g/de, and considerable fusion between the single yarns was observed. Also from 280℃
When I tried to heat treat it while raising the temperature to 320℃,
The single yarn was fused and a good heat-treated yarn could not be obtained. Example 5 The unheated fiber obtained in Example 1 was heated from 240°C to 260°C in 30 minutes in an air stream, and then further heated.
Heat treatment was continued at 260°C for 30 minutes. The obtained fiber had a single yarn fineness of 30.5 de, strength of 17.1 g/de, elongation of 3.4%,
The initial Young's modulus was 480 g/de. Examples 6 to 11 and Comparative Examples 4 to 8 The raw materials were prepared in the same manner as in Example 1, and polymerization conditions were varied as shown in the following table to obtain polymers having an intrinsic viscosity of about 0.7 to 1.2. Polymer intrinsic viscosity (ηinh), flow start temperature (Ts), shear rate at 350℃
The apparent melt viscosity (ηa) at 1000 sec ^-1 is shown in the following table. This was spun under spinning conditions similar to Example 1 (Example 2 for those with ηa of 350 poise or more). The obtained fibers are placed in a nitrogen gas stream.
Heat treatment was performed while increasing the temperature from 250°C to 280°C at a rate of 20°C/hr. (Heat treatment time 1.5 hours). The results were as shown in the following table.

[Table] From the table above, melt viscosity at flow start temperature of 280℃ or higher
It can be seen that high strength fibers can be produced in a short time only by using polymers that meet the conditions of 500 poise or higher. In addition, no fusion was observed in any of the polymers of the present invention during heat treatment.

Claims (1)

[Claims] 1 The following formulas (A), (B) and (C) It consists essentially of p-oxybenzoic acid residue (A), hydroquinone residue (B) and isophthalic acid residue (C) represented by (A)/(B) (molar ratio) of 50/50. ~
80/20, (B)/(C) (molar ratio) is 1, flow start temperature is
Polyarylate having an apparent melt viscosity of 500 poise or less at a shear rate of 1000 sec ^-1 at 280°C or higher and 350°C and an intrinsic viscosity of 0.5 or higher is melt-spun, and the resulting fibers are then heat-treated at a temperature of 180°C or higher. increased strength, characterized by
A method for producing polyarylate fiber having Young's modulus. 2 The polyarylate before melt spinning has an intrinsic viscosity of
The method according to claim 1, characterized in that the polyarylate is polymerized at a temperature of 340° C. or lower until the polyarylate reaches 0.5 or higher.