JPH01272630A - Aromatic polyester - Google Patents

Abstract

PURPOSE:To obtain the subject polymer having low melt viscosity and excellent fluidity and enabling precision forming by melt-molding, by copolymerizing a hydroquinone having a specific substituent. CONSTITUTION:The objective polymer having a logarithmic viscosity of 1.0-20.0dl/g can be produced, e.g., by the deacetylation polycondensation of (A) a monosubstituted hydroquinone having a substituent having a molecular weight of >=80, (B) a monosubstituted hydroquinone having a substituent having a molecular weight of >=80 and/or a bivalent aromatic diol, (C) terephthalic acid, (D) a dicarboxylic acid other than the component C and (E) an aromatic hydroxycarboxylic acid. The molar ratio of the component A/B is 20/80-90/10, C/D is 100/0-70/30, E/(A+B) is 2/98-80/20 and (A+B)/(C+D) is 1.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an aromatic polyester that can be melt-molded at temperatures below 400° C. and can give molded articles with excellent fluidity.

<Conventional technology> In recent years, the demand for high performance plastics has increased, and many polymers with various new performances have been developed and put on the market. Optically anisotropic liquid crystal polymers have attracted attention because of their excellent mechanical properties.

Fully aromatic polyesters are widely known as such liquid crystal polymers, and for example, homopolymers of p-hydroxybenzoic acid and copolymers of 4,4-biphenol and heptatalic acid are known.

However, the melting point of these p-hydroxybenzoic acid homopolymers and copolymers is too high and their melt fluidity is poor. Therefore, there is a method of copolymerizing p-hydroxybenzoic acid with various components to lower its melting point. considered,
For example, a method of copolymerizing P-hydroxybenzoic acid with phenylhydroquinone, terephthalic acid and/or 2,6-naphthalene dicarboxylic acid (Publication Patent Publication No. 1982-
500215), p-hydroxybenzoic acid with 2,6-
A method of copolymerizing cyhydroxynaphthalene and prephthalic acid (Japanese Unexamined Patent Publication No. 1983-50594) and a method of copolymerizing P-hydroxybenzoic acid with 2,6-hydroxyanthraquinone and terephthalic acid (U.S. Pat. 224
．． 433 specification), p-hydroxybenzoic acid with 4,4
゛ - Method of copolymerizing dihydroxybiphenyl, terephthalic acid, and isophthalic acid (Japanese Patent Publication No. 57-24407, Japanese Patent Publication No. 60-25046) Method of copolymerizing phenylhydroquinone and terephthalic acid with droxybenzoic acid (U.S. Pat. No. 4,242,496) and the like are known.

Furthermore, as an example of using cyclohexylhydroquinone, a method is known in which cyclohexylhydroquinone and terephthalic acid are copolymerized (U.S. Pat. No. 4,447,593). As an example used, a method of copolymerizing 1-phenylethylhydroquinone, phenylhydroquinone, and terephthalic acid is shown in (Publication Patent Publication No. 501207/1982).

In addition, a method of copolymerizing 1-phenylethylhydroquinone, hydroquinone, and terephthalic acid (Japanese Patent Application Laid-Open No. 59-30
No. 821) is known.

<Problems to be solved by the invention> However, although many of the polyesters obtained by these methods have a relatively low melting point of 400"C or less, they also have insufficient fluidity or heat resistance. Therefore, better fluidity and higher heat resistance are desired.

Among these, polyester consisting of P-oxybenzoic acid, 2,6-dish-droxynaphthalene, and terephthalic acid (Japanese Patent Application Laid-open No. 54-50594) is characterized by good fluidity. , low heat distortion temperature,
It was found that the heat resistance was poor, and that 2,6-cyoxynaphthalene or its derivatives were extremely likely to sublimate during polymerization, making it impossible to obtain a polymer with a uniform composition.

On the other hand, polyesters composed of P-oxybenzoic acid, 4,4-dihydroxybiphenyl, terephthalic acid, and isophthalic acid have relatively good heat resistance, but have poor fluidity during polymerization. It was found that this method has the disadvantage that it is difficult to polymerize only by melt polymerization.

On the other hand, a polymer made by copolymerizing cyclohexylhydroquinone and terephthalic acid (U.S. Pat. No. 4,447.593) and a polymer made by copolymerizing 1-phenylethylhydroquinone, phenylhydroquinone and terephthalic acid (Published Patent Publication No. 1983) Polymers copolymerized with 1-phenylethylhydroquinone, hydroquinone, and phthalic acid (Japanese Patent Laid-Open No. 59-30821) have poor fluidity and moldability compared to the heat resistance of polymers. had shortcomings.

Therefore, the object of the present invention is to obtain an aromatic polyester with improved fluidity.

Means for Solving the Problems> The present inventors have made extensive studies to solve the above problems, and as a result, have arrived at the present invention.

That is, the present invention uses a monosubstituted hydroquinone residue having a substituent having a molecular weight of 80 or more as the structural unit (I), a monosubstituted hydroquinone residue having a substituent having a molecular weight of 80 or less, and/or a divalent aromatic diol residue. is the structural unit (
IV), terephthalic acid residue in #1m exposed position ■, dicarboxylic acid residue except terephthalic acid residue in structural unit (IV),
The structural unit ■/(II) is an aromatic hydroxycarboxylic acid residue with or without a substituent as the structural unit ■.
The molar ratio of MA building units ■/(II) is 20/80 to 90/1 (III), and the molar ratio of MA building units ■/(II) is 10010 to 70/3 (II
I), the molar ratio of structural units ■/[■+■] is 2/98 to 8
0/20, ((I) 10] and [■-←■] are in substantially equimolar proportions, and dissolved in pentafluorophenol at 60°C at 0.1 g/d j! When the logarithmic viscosity is 1,0 to 1 (III), Od j! /
f is an aromatic polyester. Examples of the monosubstituted hydroquinone residue having a substituent having a molecular weight of 80 or more, which is a structural unit, include those shown by the following structural units.

A molecule that is C6H5C6H5 structural unit ■! Examples of the monosubstituted hydroquinone residue and/or divalent aromatic diol residue having a substituent of E80 or less include those shown by the following structural units.

The terephthalic acid residue, which is #1 unit (■), is shown by the following structural unit.

Examples of the dicarboxylic acid residue other than terephthalic acid, which is the structural unit (2), include those having the following structural unit.

Examples of the aromatic hydroxycarboxylic acid residue with or without a substituent which is the structural unit (■) include the following r
Examples include those shown as 4 units.

Structural unit (I), ■ is derived from the corresponding diol, structural unit O, @ is derived from the corresponding dicarboxylic acid, conceptual unit ■ is derived from the corresponding hydroxycarboxylic acid, and each structural unit is used in combination or in combination. .

In the present invention, the molar ratio of the structural unit ■/(II) is 20
/80 to 90/10, preferably 25/75 to 9
It is 0/10. Structural unit ■ has a good balance between thermal properties and fluidity, but because it has large and bulky substituents,
If used in excess, heat resistance will deteriorate. Therefore, it is preferably used in combination with the structural unit (2). The structural unit is a)
/(II) molar ratio is 10010 to 70/30,
Preferably it is 10010 to 80/20.

The molar ratio of the structural unit ■7/[■+■] is 2/98 to 80/
20 is used. If it is higher than 2/98, the high heat resistance characteristic of the structural unit (■) will not be exhibited, and if it is lower than 80/20, the characteristics of (■) will not be exhibited.By copolymerizing these in a preferred ratio, fluidity This makes it possible to create a polymer with a good balance of heat resistance and heat resistance.

Further, [■+■] and [■+■] are substantially equimolar, and when they are equal, a polymer with a high molecular weight can be obtained.

The aromatic polyester of the present invention can be produced according to the conventional polycondensation method for polyester, and there are no particular restrictions on the production method, but typical production methods include, for example, the following (1) to
(4) One example is the law.

(1) Acylated products of dihydroxycarboxylic acids such as p-acetoxybenzoic acid, acylated products of aromatic dihydroxy compounds such as cyclohexylhydroquinone diacetate, 4,4"-diacetoxybiphenyl, and aromatic compounds such as terephthalic acid. A method of producing from dicarboxylic acid by deacetic acid polycondensation reaction.

(2) Acetic acid depolycondensation from hydroxycarboxylic acids such as P-hydroxybenzoic acid, cyclohexylhydroquinone, aromatic dihydroxy compounds such as 4,4-monodihydroxybiphenyl, aromatic dicarboxylic acids such as terephthalic acid, and acetic anhydride. A method of manufacturing by reaction.

(3) Removal of phenyl esters of hydroxycarboxylic acids such as P-hydroxybenzoic acid, aromatic dihydroxy compounds such as cyclohexylhydroquinone and 4,4-dioxybiphenyl, and diphenyl esters of aromatic dicarboxylic acids such as terephthalic acid. Phenol [method of production using a stand.

(4) After reacting a desired amount of diphenyl dicarbonate with a p-hydroxycarboxylic acid such as p-hydroxybenzoic acid and an aromatic dicarboxylic acid such as terephthalic acid to form a phenyl ester, cyclohexylhydroquinone, 4, A method in which an aromatic dihydroxy compound such as 4'-dihydroxybiphenyl is added and a phenol-depleted polycondensation reaction is performed.

Typical catalysts used in the polycondensation reaction are metal compounds such as stannous acetate, tetrabutyl titanate, lead acetate, antimony trioxide, magnesium, sodium acetate, potassium acetate, and trisodium phosphate, but non-catalytic But it doesn't matter.

Further, the melt viscosity of the aromatic polyester of the present invention is 50 to
25,000 voices is preferred, especially 100-10.0
00 voids is more preferred.

Note that this melt viscosity is a value measured using a Koka type flow tester under conditions of (liquid crystal start temperature + 30° C.) and a slip rate of 1,000 (1/sec).

These aromatic polyesters have a concentration of 0.1! in pentafluorophenol at 60°C. It is necessary that the logarithmic viscosity when dissolved at a concentration of % by weight is 1.0 to 20.0 d 1 /g, and particularly preferably 2.0 to 10.0 d 1 /g.

When polycondensing the aromatic polyester of the present invention, aromatic dihydroxy compounds such as bisphenol A, bisphenol S, resorcinol, and 4,4゛-dihydroxydiphenyl sulfide are used in addition to the components constituting the above (I) to Further, P-aminophenol, P-aminobenzoic acid, etc. can be further copolymerized in a small proportion so as not to impair the object of the present invention.

The aromatic polyester of the present invention thus formed has a melting point of 40
It has a low temperature of 0°C or less, and can be subjected to ordinary melt molding such as extrusion molding, injection molding, compression molding, and blow molding, and can be processed into fibers, films, three-dimensional molded products, containers, hoses, etc. .

In addition, during molding, for the aromatic polyester of the present invention,
Reinforcing agents for glass fiber, carbon fiber, asbestos, etc., fillers, nucleating agents, pigments, antioxidants, stabilizers, plasticizers, lubricants,
Additives such as mold release agents and flame retardants and thermoplastic resins can be added to impart desired properties to the molded article.

Note that the strength of the thus obtained molded article can be increased by heat treatment, and the elastic modulus can also be increased in many cases.

This heat treatment involves leaving the molded part in an inert atmosphere (e.g. nitrogen,
This can be done by heat treatment at a temperature below the melting point of the polymer in an oxygen-containing atmosphere (eg air) or under reduced pressure. This heat treatment may or may not be under tension, and can be carried out for a period of several tens of minutes to several days.

The molded article obtained from the aromatic polyester of the present invention has good optical anisotropy and heat resistance due to its parallel molecular arrangement, and has extremely excellent fluidity.

<Example> The present invention will be explained in more detail with reference to Examples below.

Example 1 131.3 g of cyclohexylhydroquine diacetate (Ia) (47.5X
10-2 mol), phenylhydroquinone diacetate (IIc) 128.4g (47゜5X10-2 mol), terephthalic acid (III) 157゜8g (95.0
X 10-2 mol hp-acetoxybenzoic acid (Va) 9
．． 0+r (5X10-2 mol) and reacted at 250 to 350°C for 3 hours in a nitrogen gas atmosphere.
2 at 50°C. When the pressure was reduced to OIffIHg and further reduced for 1 hour, an almost stoichiometric amount of acetic acid was distilled out, and a tough polymer was obtained.

The theoretical structural formula of this polymer is shown below.

The elemental analysis results were in good agreement with the theoretical structural formula.

R/rn/n=5/47.5/47
．． 5 The liquid crystal initiation temperature (temperature showing optical anisotropy) of this polymer was measured using a melting point microscope and found to be 315°C. Also, 6 at a concentration of 0.1 t/dβ of the polymer
The solution viscosity in pentafluorophenol at 0°C is 3
．． It was 1 d1/t.

When the melt viscosity of this polymer was measured using a high-low flow tester, it showed very good fluidity of 2.000 voids at 345° C. and a shear rate of 1.000<1/sec).

Examples 2 to 8, Comparative Examples 1 to 3 As in Example 1, 1-phenylethylhydroquinone diacetate (Ib), (1-)uni-1-methyl)ethylhydroquinone diacetate (Ic), 4. 4
---Diacetoxybiphenyl (IIa), hydroquinone diacetate (nb), t-butylhydroquinone diacetate-(nd), 2,6-diacedoxynaphthalene (■e), isophthalic acid (IVa) as raw materials Additionally, polymerization was evaluated. Further, the melt viscosity was measured under the conditions of (liquid crystal starting temperature + 30° C.) and a shear rate of 1,000 (1/sec). These results are summarized in Table 1.

It can be seen that all of the examples have lower melt viscosity than Comparative Examples 1 to 3, and are polymers with excellent fluidity that can be particularly precisely molded.

<Effects of the Invention> The aromatic polyester of the present invention has a relatively low melt viscosity and good fluidity, especially '! It is a polymer that can be molded into l# dense molding.

Claims (1)

[Scope of Claims] Structural unit (I) is a mono-substituted hydroquinone residue having a substituent with a molecular weight of 80 or more, a mono-substituted hydroquinone residue having a substituent with a molecular weight of 80 or less and/or a divalent aromatic diol residue structural unit (II), terephthalic acid residue as structural unit (III), dicarboxylic acid residue other than terephthalic acid residue as structural unit (IV), aromatic hydroxycarboxylic acid residue with or without substituents is the structural unit (V), the molar ratio of structural units (I) / (II) is 20/80 to 90/10, the molar ratio of structural units (III) / (IV) is 100/0 to 70/30, Structural unit (V)/[
The molar ratio of (I) + (II)] is 2/98 to 80/20, and [(I) + (II)] and [(III) + (IV)] are in substantially equal molar proportions. An aromatic polyester having a logarithmic viscosity of 1.0 to 20.0 dl/g when dissolved at 0.1 g/dl in pentafluorophenol at 60°C.