JPS59124925A - Fully aromatic polyester - Google Patents

Abstract

PURPOSE:A fully aromatic polyester melt-moldable even at below 300 deg.C and capable of forming a molding of excellent mechanical properties (high rigidity and low anisotropy), comprising structural units of four specified aromatic ring groups. CONSTITUTION:A polyester comprising (A) 5-20mol% structural unit of formula I , (B) 35-65mol% structural unit of formula II, (C) 15-45mol% structural unit of formula III, and (D) 5-20mol% structural unit of formula IV (with the proviso that unit A and unit B are present in substantially equimolar amounts) and having a logarithmic viscosity (a value obtained by dividing the natural logarithm of a relative viscosity by the concentration of a sample solution) of at least 0.4dl/g. The above fully aromatic polyester is formed by polymerizing terephthalic acid, p-hydroxybenzoic acid, m-hydroxybenzoic acid, and 1,4-naphthalenediol, each in a necessary amount, at about 250-350 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel wholly aromatic polyester that is melt-polymerizable, melt-moldable, resinous, and has excellent mechanical properties.

In recent years, whether it is fiber, film cut, or molded products,
There is an increasing demand for materials with excellent rigidity, heat resistance, and chemical resistance. Polyester has become widely accepted for use in general molded products, but many polyesters have poor mechanical properties such as flexural modulus, so they are not suitable for applications that require high strength. . In order to improve this mechanical property, it is known to blend reinforcing materials such as calcium carbonate and glass fiber, but this increases the specific gravity of the material, which reduces the lightweight advantage of plastic. During molding, the molding machine is subject to severe wear, which causes many practical problems. No need for reinforcement material
In recent years, liquid crystalline polyester has attracted attention as a polyester suitable for applications requiring high strength. What has attracted particular attention is the Journal of Polymer Science Polymer Chemistry Edition, /4' volume (/q7A) λO'
This is after W. J. Jacquelin published a thermoliquid crystal polymer consisting of polyethylene terephthalate and hydroxybenzoic acid on page 1.3. Among them, Jacran reported that this liquid crystal polymer exhibits more than 3 times the stiffness of polyethylene terephthalate, more than 7 times the strength, and 1.2 times more impact strength than polyethylene terephthalate, opening new possibilities for high-performance resins. showed his sexuality. onwards,! JP-A Showa S3-Mu5guco/(DuPont), JP-A Showa 5ll-Left T9! ;91I (Celanese), special 1)
Showa 5s-2/lI9/ (Engineering OI), JP-A Showa, 5--
soo-ichi (Ros Boulin), Tokukai Sho! ;! -10
622θ (Fiber Industry) and other liquid crystal polyesters are being developed with the aim of achieving both improved strength and rigidity as well as melt moldability. However, although more than 100 types of liquid crystal polyester have already been proposed,
There have been no successful molded products yet. This is because these polymers exhibit a high degree of orientation in the molten state, resulting in large anisotropy in mechanical properties.

The present inventors have arrived at the present invention as a result of intensive studies aimed at alleviating the anisotropy of mechanical properties.

The gist of the present invention is as follows (A), (B), (C) and (
D), the units (A) and (D) are present in substantially equimolar amounts, and the unit (B) is present in substantially equimolar amounts;
Contains 3S~S mol%, Je-Q(0) in /ri~q left molar relationship and unit (Di fri~20 mol%,
The wholly aromatic polyester is characterized by having a logarithmic viscosity of at least o, ti dt7y.

The wholly aromatic polyester of the present invention exhibits liquid crystallinity in a molten state, can be melt-molded, and has the characteristics of having little anisotropy in the physical properties of a molded product.

In the following, the present invention will be described in detail. The fully aromatic polyester of the present invention essentially consists of two structural units (Al
From (B), (C) and (D).

The structure (Earth) is a terephthaloyl group, and terephthalic acid 7 is derived from its derivatives such as alkyl esters. Unit (A) is 5-20 of wholly aromatic polyester
It is present in a molar ratio, preferably g~/molar ratio (degrees), and in an equimolar amount with the structural unit (D).

The structural unit (B) is a p-oxybenzoyl group, and p
- derived from hydroxybenzoic acid or its derivatives such as alkyl esters. Monomer (B) is present in a concentration of 3S to 65 moles of fully aromatic polyester, preferably 73 to 53 moles.

Structural unit (C) is m-oxybenzoyl group, m
- derived from hydroxybenzoic acid or its derivatives such as alkyl esters. unit (C1, 14'5 mole per unit of wholly aromatic polyester, preferably 2s to 35
Exists in molar concentrations.

The structural unit (D) is a /, 4'-dioxynaphthyl group, derived from /, ternaphthalene diol or a derivative thereof such as an alkyl ester.

The unit (D) has a concentration of 3 to 20 mol of the wholly aromatic polyester, preferably g~/left mol, and the structural unit (
A) is present in an equimolar amount.

Structural units (A) and (B) are disparate substitutes, and have the effect of improving the mechanical properties of the wholly aromatic polyester by forming a rigid structure. On the other hand, since the molecular structure of structural units (C) and (D)' is asymmetric with respect to the main chain of fully aromatic polyester, the rigidity of the molecular structure developed from units (A) and (B) is It has a relaxing effect. In other words, a wholly aromatic polyester having a liquid crystal temperature range in which melt molding is possible can be produced.
The m-hydroxyl group in C') has the effect of bending the direction of the main chain from a straight chain to a direction of 60°, and therefore has the effect of reducing the anisotropy of the molded article. Therefore, units (0) and (
By adjusting the concentration ratio of D), it is possible to obtain a polymer that is melt moldable, has high mechanical properties, and has low anisotropy in physical properties. The fully aromatic polyester of the present invention has a logarithmic viscosity of at least 0.4 tdt/r (logarithmic viscosity is the natural logarithm of the relative viscosity divided by the concentration of the sample solution υ; in this measurement, the viscosity solvent is Using a mixed solvent of tetrachloroethane/phenol=/// (weight ratio), it was measured at a concentration of QJ wt%), for example, 0.5 to eight left eLt/? An optical method using polarized light microscopy is suitable for determining whether or not a material can exhibit anisotropy in a molten state with a logarithmic viscosity of 0. That is, optical anisotropy is observed by transmission or reflection under a polarizing microscope equipped with a heat stage. When the temperature is gradually raised from room temperature, polymers that do not exhibit anisotropy are observed to immediately change to an isotropic melt at the melting point, but polymers that exhibit anisotropy generally change from a crystalline state to a certain state. It becomes a liquid crystal state at a certain temperature, and exhibits a stable liquid crystal state over a fairly wide temperature range (temperature range, for example, /θC or higher). Thereafter, the temperature increases and the melt changes to an isotropic melt.

The simplest method is to determine anisotropy by observing such optical anisotropy.

The wholly aromatic polyester of the present invention can be produced by a melt polymerization method. That is, terephthalic acid, p-hydroxybenzoic acid, m-hydroxybenzoic acid, and nitric naphthalene diol (which may be derivatives) are mixed and melted, usually under normal pressure, to a temperature of 1 kOC to 3! ; Polymerize by heating to a temperature of about OC. To promote the polymerization reaction (C4oo% reaction), by-products (acetic acid, acetic ester, etc.)
must be removed from the system, and for this reason, as soon as the by-products stop distilling under normal pressure, j! 'jl ba/mi'I
After reducing the pressure to below H, the polymerization reaction is carried out from the distillation of by-products, and the reaction is terminated when the degree of polymerization of the produced polymer has sufficiently increased to a reaction rate of 11 mm/.00C4. In addition, the fully aromatic polyester of the present invention has a reaction temperature of:
It has the advantage that even a left o'6 to 300C can be used immediately.

The fully aromatic polyester of the present invention can be molded into an insect acid mold even at temperatures below 300C, and the molded product has high rigidity (modulus of elasticity). It is useful as a material for electronic material parts such as , bobbins, etc.

EXAMPLES The present invention will be specifically explained below with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist thereof.

Examples/and Comparative Examples/~3 Terephthalic acid/iA f, p-acetoxybenzoic acid 9
0. C2, m-acetoxybenzoic acid 5+', C2 and/or lI-su7talendibenzoic acid, 2 #4 f were charged into a polymerization tube equipped with a stirrer, and after purging with nitrogen three times, the polymerization tube was I put it in a '6 oil bath. The mixture was stirred for 7 hours under a nitrogen stream, during which time most of the acetic acid was distilled off.

Then 0. ! After creating a vacuum of Torr, the mixture was stirred for 30 minutes to complete the polymerization. What is the logarithmic viscosity of this polymer? ,
It was 7j.

This polymer has a temperature range from 6θC to 3jtO, which is the upper limit of the measurement temperature.
It exhibited optical anisotropy in the molten state in the temperature range up to Optical anisotropy was observed using a Nikon polarization microscope QPOH model equipped with a Zeiss heat stage.

The measured modulus values are shown in Table 1 along with the Danitzk modulus values of other polymers. The XI′ nick modulus value is ((
Botoyo Seiki Seisakusho's dynamic modulus tester, Dynamic Modulus, Te5terP
The speed of sound (υ) traveling through the strand-like polymer was measured using P M -''R■, and calculated using Laplace's formula (% formula %):

Table-/ */: Tsubamitsudo/θ10-J, Tsubamitsudo is a registered trademark of Mitsubishi Chemical Industries ■, 2: Toning, 203, Torlon is a registered trademark of Mitsubishi Chemical Industries, Ltd. Registered trademark of strain Example λ~/ll Same as Example/S with different compositions of terephthalic acid, p-acetoxybenzoic acid, m-acetoxybenzoic acid and /, /I-natutalendibenzoic acid, Example/S and comparison. For example, the polymer obtained in Example 1 was made into a strand with a diameter of 3 mm using an extruder, and a 3 rran square tip was cut out from the strand and the compressive strength was measured.

The compression speed is /rrrm 7 seconds and 10% of the initial thickness
Compressive strength was calculated by dividing the maximum load required for deformation by the cross-sectional area (
ASTMD-/Ayu/). The number of test pieces is S in the direction parallel to the strand and in the direction perpendicular to the strand. The measuring equipment used was a Tensilon tester and a groaner (Toyo Baldwin).

Table 3 shows typical liquid crystalline polyesters (manufactured by Mitsubishi Chemical Industries (V)), intrinsic viscosity 1yo, t, t, (tetrachlorethylene/phenol 50/0 (weight ratio) mixed solvent/?, At a concentration of 7 dl, ? o CTiflll constant)
90 moles of polyethylene terephthalate and p-acetoxybenzoic acid. The compressive strength of (produced from the molar ratio) was measured and is also shown.

Table 3; To +: #p Parallel to the strands * Left: * At right angles to the direction Further, the polymer obtained in Example
A flat plate of gO .Shi1Nonda-TemperatureΩ3θ
~2jtOC.

The flat plate was cut into a rectangular shape in the resin flow direction (MD) and the direction perpendicular thereto (TD), and the bending elastic modulus and bending strength were measured (ASTMD7qO). The measuring device used was a Tensilon testing machine (Toyo Baldwigi). Display the results -
As shown in the figure below.

table - group

Claims (1)

[Claims] (1) Consisting of the following formulas (A), fB'l, (C) and (D, l) (・Seizo unit (B) -a, -C) -c - 1, (D) is present in substantially equimolar amounts, with units < A) &-20 molar ratios of 5 units (B) ranging from 35 to 4. t molar coefficient, units (0) in the ratio of 7S to tis molar and units (D) in the ratio of polyester