Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – From phenol – phenol ether – or inorganic phenolate
Reexamination Certificate
2001-07-19
2002-11-19
Acquah, Samuel A. (Department: 1711)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
From phenol, phenol ether, or inorganic phenolate
C528S176000, C528S180000, C528S183000, C528S185000, C528S194000, C528S195000, C528S206000, C528S208000, C528S209000, C528S210000, C528S211000, C528S278000, C528S288000, C528S302000, C528S307000, C528S308600
Reexamination Certificate
active
06482915
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method for producing a thermotropic liquid crystalline polymer of high quality at high production yield.
2. Background Art
Thermotropic liquid crystalline polymers are expensive, since the polymers are produced from expensive aromatic monomers. Thus, reduction of the high production costs thereof is a big issue. In order to reduce costs, elevating the production yield of the polymers is considered to be one solution.
In order to increase the yield of such polymers, a technique is proposed in which the temperature of a reactor is elevated during discharging of the produced polymer after polymerization is completed, thereby lowering the melt viscosity of the polymer. However, in the technique, the polymer is discolored due to heat deterioration, forming a black-brown polymer. In addition, more severe heat deterioration produces gases of low boiling components such as phenol (PhOH), benzoic acid (BA), hydroxybenzoic acid (HBA), and a phenol ester thereof (HBA-Ph) and black specks (carbonized matter, abbreviated as BS), thereby affecting the quality of the produced polymer. Furthermore, when the reactor is filled with the low-boiling gases, discharge of the product from the reactor is unstable, resulting in decrease in the recovery ratio.
U.S. Pat. No. 4,720,424 discloses a process for preparing thermotropic LCP comprising units a)-f) in the presence of an acylating agent and catalyst in columns 7-13 and 25. However, as seen from the descriptions at column 11, lines 56-64 and all examples of U.S. Pat. No. 4,720,424, 2.0 to 4.2 percent molar excess of dicarboxylic acid monomer is essential and the range is much larger than the range of equation (1) of the present invention. If the molar excess ratio of the carboxyl group is too excessive to the value of the equation (1), the reaction time is remarkably long, and as a result, productivity lowers.
U.S. Pat. No. 5,155,204 discloses a process for preparing thermotropic LC aromatic copolymers in the presence of acylating agent such as acetic anhydride and catalysts in columns 7-9, 11-13, 15 and 19. However, as seen from the descriptions at column 9, lines 45-47 of U.S. Pat. No. 5,155,204, the molar ratio of the repeating dicarboxy units to the dioxy units is always very close to 1 and in all examples the molar ratio is 1.0 and this 1.0 corresponds to 0 in equation (1) of the present invention, and as a result, evolution of low-boiling gases increases.
In view of the foregoing, an object of the present invention is to provide a method for producing a high-quality thermotropic liquid crystalline polymer at high yield including the recovery ratio of the polymer from a reactor, and further in short production time, which method prevents evolution of low-boiling gases and discoloration due to heat deterioration.
SUMMARY OF THE INVENTION
In order to solve the aforementioned problems, the present inventor has conducted extensive studies, and have found that when the proportions among the amounts of starting monomers, the amount of an acylating agent, and the amount of a catalyst are maintained to specific conditions, then the evolution of low-boiling gases is suppressed, and discharge of a high-quality polymer without discoloration due to heat deterioration from a reactor at a high recovery ratio can be achieved, and further, without production time being prolonged. The present invention has been accomplished on the basis of this finding.
Accordingly, the present invention provides a method for producing a thermotropic liquid crystalline polymer, which method comprises polymerizing starting monomers in the presence of an acylating agent,
said starting monomers comprising a carboxyl group-containing compound, a hydroxyl group-containing compound, an amino group-containing compound, an ester derivative thereof, and/or an amide derivative thereof, which are selected from the group consisting of compounds represented by the following components I, II, III, and IV:
(I) an aromatic hydroxycarboxylic acid and an ester derivative thereof;
(II) an aromatic dicarboxylic acid and an alicyclic dicarboxylic acid;
(III) an aromatic diol, an alicyclic diol, an aliphatic diol, and an ester derivative thereof; and
(IV) an aromatic hydroxyamine, an aromatic diamine, an ester derivative thereof, and an amide derivative thereof,
wherein the starting monomers, the acylating agent, and a catalyst are charged so as to satisfy the following equations (1) to (4):
0.0015≦((
A
)−(
B
))/((
A
)+(
B
))≦0.006 (1);
1.01≦(
D
)/(
C
)≦1.08 (2);
0≦(
E
)≦40 (3);
and
(
D
)/(
C
)≧−0.002×(
E
)+1.04 (4),
wherein
(A) denotes the total amount by equivalent (with respect to a carboxyl group) of starting monomers I and/or II;
(B) denotes the total amount by equivalent (with respect to a hydroxyl group, an amino group, an ester derivative group thereof, and an amide derivative group thereof) of starting monomers I, III, and/or IV;
(C) denotes the total amount by equivalent (with respect to a hydroxyl group and an amino group) of starting monomers I, III, and/or IV;
(D) denotes the amount by equivalent of an acylating agent; and
(E) denotes the amount of a catalyst (as reduced to amount by weight of metal, unit: ppm).
In the method for producing a thermotropic liquid crystalline polymer of the present invention, (I) an aromatic hydroxycarboxylic acid and an ester derivative thereof comprises the following composition:
(Ia) hydroxybenzoic acid and an ester derivative thereof, and
(Ib) hydroxynaphthoic acid and an ester derivative thereof,
wherein molar ratio of (Ia)/((Ia)+(Ib))≧0.9, and the catalyst is charged so as to satisfy the following equation (3′):
0≦(
E
)≦20 (3′).
Preferably, in the method for producing a thermotropic liquid crystalline polymer, all of the starting monomers I, II, III, and IV are aromatic compounds.
Preferably, in the method for producing a thermotropic liquid crystalline polymer, all of the starting monomers, the acylating agent, and the catalyst are charged into the same reactor, and the resultant mixture is caused to react.
Preferably, in the method for producing a thermotropic liquid crystalline polymer, hydroxyl groups and/or amino groups of the starting monomers I, III, and/or IV are acylated by the acylating agent, and subsequently, the acylated product is caused to react with the starting monomer II.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
The thermotropic liquid crystalline polymer of the present invention is produced from starting monomers comprising a carboxyl group-containing compound, a hydroxyl group-containing compound, an amino group-containing compound, an ester derivative thereof, and/or an amide derivative thereof, which are selected from the group consisting of compounds represented by the following components I, II, III, and IV:
(I) an aromatic hydroxycarboxylic acid and an ester derivative thereof;
(II) an aromatic dicarboxylic acid and an alicyclic dicarboxylic acid;
(III) an aromatic diol, an alicyclic diol, an aliphatic diol, and an ester derivative thereof; and
(IV) an aromatic hydroxyamine, an aromatic diamine, an ester derivative thereof, and an amide derivative thereof.
In the method for producing a thermotropic liquid crystalline polymer of the present invention, as the component (I), a specific composition of an aromatic hydroxycarboxylic acid and an ester derivative thereof, which comprises
(Ia) hydroxybenzoic acid and an ester derivative thereof, and
(Ib) hydroxynaphthoic acid and an ester derivative thereof,
(wherein molar ratio of (Ia)/((Ia)+(Ib))≧0.9), is used.
Examples of aromatic hydroxycarboxylic acids serving as the aforementioned component (I) include aromatic hydroxycarboxylic acids such as 4-hydroxybenzoic acid, 3-hydroxybenzoic acid, 6-hydroxy-2-naphthoic acid, and 6-hydroxy-1-naphthoic acid; alkyl-substituted aromatic hydroxycarboxylic acids such as 3-methyl-4-hydroxybenzoic acid, 3,5-dimethy
Acquah Samuel A.
Nixon & Vanderhye P.C.
Polyplastics Co. Ltd.
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