JP2555573B2 - High impact aromatic polyester - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Field of Industrial Application> The present invention relates to an aromatic polyester that can be melt-molded at 400 ° C. or lower and can give a molded article having excellent fluidity, heat resistance and impact resistance. is there.

<Prior art> In recent years, there has been an increasing demand for higher performance of plastics, and a number of polymers having various new properties have been developed and marketed. Among them, the polymer is particularly characterized by a parallel arrangement of molecular chains. It has been noted that liquid crystal polymers having optical anisotropy have excellent mechanical properties.

As the liquid crystal polymer, a wholly aromatic polyester is widely known, and for example, a homopolymer and a copolymer of p-hydroxybenzoic acid are known. However,
The p-hydroxybenzoic acid homopolymers and copolymers often have too high melting points and poor melt flow properties. Therefore, a method of copolymerizing various components with p-hydroxybenzoic acid and lowering the melting point thereof has been studied. For example, p-hydroxybenzoic acid is copolymerized with phenylhydroquinone, terephthalic acid and / or 2,6-naphthalenedicarboxylic acid. Method (published patent publication No. 55-50
No. 0215), a method for copolymerizing p-hydroxybenzoic acid with 2,6-dihydroxynaphthalene and terephthalic acid.
54-50594), a method of copolymerizing p-hydroxybenzoic acid with 2,6-dihydroxyanthraquinone and terephthalic acid (US Pat. No. 4,224,433), p-hydroxybenzoic acid with 4,4′-dihydroxybiphenyl. Method of copolymerizing terephthalic acid and isophthalic acid (Japanese Patent Publication No.
JP-B No. 60-25046), and a method of copolymerizing phenylhydroquinone and terephthalic acid with p-hydroxybenzoic acid (US Pat. No. 4,238,600) and the like.

<Problems to be Solved by the Invention> However, many of the aromatic polyesters obtained by these methods have a relatively low melting point of 400 ° C. or less, but have insufficient fluidity, heat resistance or resistance. Since the impact resistance is insufficient, further improvement in good fluidity, higher heat resistance and higher impact resistance are desired.

Of these, polyesters composed of p-hydroxybenzoic acid and 4,4'-dihydroxybiphenyl, terephthalic acid and isophthalic acid have the characteristic of relatively good heat resistance, but on the other hand, they have a fluidity during polymerization. However, it was found that it was difficult to carry out polymerization only by melt polymerization. Moreover, it was also found that the impact resistance was not always sufficient.

On the other hand, it was found that the polyester composed of p-hydroxybenzoic acid, 2,6-dihydroxynaphthalene and terephthalic acid had relatively good fluidity and impact resistance, but poor heat resistance.

Therefore, the present invention aims to obtain an aromatic polyester having excellent fluidity, heat resistance and impact resistance.

<Means for Solving the Problems> As a result of intensive studies to achieve the above object, the present inventors have found that p-hydroxybenzoic acid, t-butylhydroquinone, 4,4′-dihydroxybiphenyl and / or
The inventors have found that an aromatic polyester obtained by copolymerizing an aromatic polyester composed of 2,6-dihydroxynaphthalene and terephthalic acid with a specific aromatic oxycarboxylic acid meets the above-mentioned object, and completed the present invention.

That is, the present invention comprises the following structural units (A) to (D), and the total of the structural units (A) and (B) is 40 to 40 relative to the total of the structural units (A), (B) and (C). 90 mol%, the structural unit (C) is 60 to 10 mol% with respect to the total of the structural units (A), (B) and (C), and the structural unit (B) is composed of the structural units (A) and (B). 1 to 40 mol% of the total, the structural unit (C) and the structural unit (D) are substantially equimolar, and the logarithmic viscosity (measured in pentafluorophenol at a concentration of 0.1 g / dl at 60 ° C.) The high impact aromatic polyester is characterized by being 1.0 to 8.0 dl / g.

O-Y-O (C) (Where X is It is 1 or more types chosen from, and Y shows either of the following-.

In the aromatic polyester of the present invention, the structural unit (A) is a structural unit formed from p-hydroxybenzoic acid, and the structural unit (B) is m-hydroxybenzoic acid, 3
-Shows a structural unit formed from one or more selected from chloro-4-hydroxybenzoic acid and 2,6-hydroxynaphthoic acid.

The structural unit (C) represents a structural unit selected from the following'- '.

Two types of structural units, a structural unit formed from't-butylhydroquinone and a structural unit formed from 4,4'-dihydroxybiphenyl. A structural unit formed from't-butylhydroquinone and a structural unit formed from 2,6-dihydroxynaphthalene. Two structural units of the unit, structural units produced from't-butylhydroquinone,
Three types of structural units, a structural unit generated from 4,4'-dihydroxybiphenyl and a structural unit generated from 2,6-dihydroxynaphthalene, The structural unit (D) is a structural unit generated from terephthalic acid.

The total amount of the structural units (A) and (B) is 40 to 90 with respect to the total amount of the structural units (A), (B) and (C).
Mol%, preferably 60 to 80 mol%, the structural unit (C) is 60 to 60% based on the total of the structural units (A), (B) and (C).
10 mol%, preferably 40 to 20 mol%, structural unit (B)
Is 1 to 40 mol%, preferably 1 to 10 mol%, based on the total of the structural units (A) and (B), and the structural unit (C)
And the structural unit (D) are substantially equimolar. Outside the above composition range, the fluidity is poor and the heat resistance is poor, so that the object of the present invention cannot be achieved.

Also, the heat distortion temperature (ASTM D648) of the injection-molded product obtained from the aromatic polyester composed of the above structural units (18.
A composition in which 56 kg / cm ² ) is 150 ° C. or higher is preferable.

The aromatic polyester of the present invention can be produced according to conventional polycondensation of polyester, and the production method is not particularly limited, but typical production methods include, for example, the following methods (1) to (3). Can be mentioned.

(1) A method of producing an acylated product of an aromatic hydroxycarboxylic acid such as p-acetoxybenzoic acid and a diacylated product of an aromatic dihydroxy compound such as t-butylhydroquinone diacetate, and deacetic acid polycondensation reaction from terephthalic acid.

(2) A method of producing an aromatic hydroxycarboxylic acid such as p-hydroxybenzoic acid, an aromatic dihydroxy compound such as t-butylhydroquinone, terephthalic acid and acetic anhydride or diphenyl carbonate by deacetic acid or dephenol polycondensation reaction . However, 2,6
Only dihydroxynaphthalene preferably uses diacylated products.

(3) A method of producing a phenyl ester of an aromatic hydroxycarboxylic acid such as p-hydroxybenzoic acid and an aromatic dihydroxy compound such as t-butylhydroquinone and diphenylterephthalate by a dephenol polycondensation reaction.

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. It is not always necessary to use it during acetic acid polycondensation.

The logarithmic viscosity of the aromatic polyester of the present invention (measured at 60 ° C. in pentalfluorophenol at a concentration of 0.1 g / dl) is
It is preferably in the range of 1.0 to 8.0 dl / g, particularly 2.0 to 6.0 dl / g.

Further, the melt viscosity of the aromatic polyester of the present invention is 10
It is preferably in the range of 115,000 poise, especially 500 to 10,000 poise.

The melt viscosity is a value measured by a Koka flow tester at a temperature of (liquid crystal starting temperature + 50 ° C) and a shear rate of 3000 (l / sec).

When polycondensing the aromatic polyester of the present invention, in addition to the components constituting the p-acetoxybenzoic acids (A) to (D), isophthalic acid, 2,6-dicarboxynaphthalene, 4,4 ′ -Diphenylcarboxylic acid, 2,2′-diphenyldicarboxylic acid, 1,2-bis (phenoxy) ethane-4,4′-dicarboxylic acid, 1,2-bis (2-chlorophenoxy) ethane-4,4 ′ -Aromatic dicarboxylic acids such as dicarboxylic acids, alicyclic dicarboxylic acids such as hexahydroterephthalic acid, hydroquinone, bisphenol A, bisphenol S, resorcin, 4,4'-dihydroxydiphenyl ether, 4,4'-dihydroxydiphenyl sulfide, etc. Aromatic dihydroxy compounds, and p-aminophenol, p-phenylenediamine, p-aminobenzoic acid, etc. are detrimental to the object of the present invention. It can be allowed to further copolymerization in a small proportion of degree no.

The aromatic polyester of the present invention thus obtained has a melting point of
As low as 400 ℃ or less, it can be used for ordinary melt molding such as extrusion molding, injection molding, compression molding, blow molding, and can be processed into fibers, films, three-dimensional molded products, containers, hoses, etc. is there.

At the time of molding, a reinforcing agent such as glass fiber, carbon fiber, and asbestos, a filler, a nucleating agent, a pigment, an antioxidant, a stabilizer, a plasticizer, a lubricant for the aromatic polyester of the present invention,
Additives such as release agents and flame retardants, and other thermoplastic resins can be added to impart desired properties to the molded article.

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

This heat treatment causes the molded article to be placed in an inert atmosphere (eg, nitrogen,
The heat treatment can be performed at a temperature lower than the melting point of the polymer in an atmosphere containing oxygen (eg, argon, helium or water vapor) or 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 several tens of minutes to several days.

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

<Example> Hereinafter, the present invention will be described in more detail by way of examples.

Example 1 A polymerization test tube was charged with 50.08 g of p-acetoxybenzoic acid (2
7.8 × 10 ⁻² mol), 3-chloro-4-acetoxybenzoic acid 2.15 g (3.72 × 10 ⁻² mol), t-butyl hydroquinone diacetate 9.31 g (3.72 × 10 ⁻² mol), 4,4′- 20.22 g (7.48 × 10 ^-2 mol) of diacetoxybiphenyl and 18.61 g (11.2 × 10 ^-2 mol) of terephthalic acid were charged, and deacetic acid polycondensation was performed under the following conditions.

First, after reacting in a nitrogen gas atmosphere at 250 to 340 ° C. for 3 hours, the pressure was reduced to 1.1 mmHg, and further polycondensation reaction was performed at 340 to 350 ° C. for 0.3 hour to obtain a brown polymer.

Further, 5 batches of polycondensation were carried out under the same conditions as above, and the polymer was pulverized by a pulverizer manufactured by Toho Co., Ltd.

The theoretical structural formula of this polymer is as follows, and the elemental analysis results of the aromatic polyester showed good agreement with the theoretical values as shown in Table 1.

l / m / n / o / p = 69.5 / 2.5 / 9.3 / 18.7 / 28m / (l + m) = 3.5 mol% However, O (%) = 100 (%)-C (%)-H (%)
Calculated from -Cl (%).

When the logarithmic viscosity of this aromatic polyester was measured in pentafluorophenol (0.1g / dl concentration, 60 ° C)
It was 3.8 dl / g.

In addition, when this aromatic polyester was placed on the sample stage of a polarizing microscope and the temperature was raised to check the optical anisotropy,
Good optical anisotropy was exhibited at 6 ° C or higher.

This aromatic polyester was supplied to Sumitomo Nestal injection molding machine Promat 40/25 (Sumitomo Heavy Industries, Ltd.),
Cylinder temperature 350 ℃, mold temperature 30 ℃, 1/8 ″
Thick, x 1/2 "wide x 5" long test piece and 1/8 "thick,
A mold notch impact test piece of × 2 · 1/2 ″ width × 2 ″ length was prepared.

Using a test piece made of Toyo Baldwin's Tensilon UTM-100, strain rate 1 mm / min, span distance
The flexural modulus measured under the condition of 50 mm was 13 GPa. Izod impact value (mold notch) is 32 kg / cm / c
It showed a high value of m.

Also, using a thermal deformation measuring device manufactured by Toyo Seiki Co., Ltd.
The heat distortion temperature of an 8 ″ thick test piece was measured to be 223 ℃ (1
It had excellent heat resistance of 8.56 kg / cm ² ).

The melt viscosity of this aromatic polyester is 350 ° C,
The shear rate was 3000 (l / sec) and the porosity was 2,500 and the flowability was good.

Examples 2-5, Comparative Examples 1-4 In a round bottom flask, p-hydroxybenzoic acid (I), m
-Hydroxybenzoic acid (II), 3-chloro-4-hydroxybenzoic acid (III), 2,6-hydroxynaphthoic acid (I
V), t-butylhydroquinone (V), 4,4′-dihydroxybiphenyl (VI), 2,6-diacetoxynaphthalene (VII) and terephthalic acid (VIII), (V), (V
I) and (VII) and (VIII) were equimolar so that the composition shown in Table 2 was added, and acetic anhydride was further added to double the total of (V) and (VI). I), (II), (III) and (IV) were added in an amount of 1.05 times the total amount added, and deacetic acid polycondensation was carried out under the following conditions.

First, the reaction was carried out at 130 to 280 ° C. for 3 hours in a nitrogen gas atmosphere, and then at 280 to 340 ° C. for 1 hour. afterwards
The pressure was reduced to 1.5 mmHg or less, and the polycondensation reaction was further performed at 340 to 350 ° C. for 0.8 hours to obtain a brown polymer.

The liquid crystal starting temperature and logarithmic viscosity of this polymer were measured, and injection molding was performed at (liquid crystal starting temperature + 50 ° C), and Izod impact value (mold notch) and heat distortion temperature (18.56kg /
cm ²⁾ was measured.

 The results are shown in Table 2.

As is clear from Examples 2 to 5, the aromatic polyester of the present invention has excellent impact resistance and heat resistance.

On the other hand, polymers other than the present invention have a heat resistance of 145
Lower than ℃ (Comparative Example 3), impact resistance is 20kgcm / c
m was inferior to the present invention (Comparative Example 4) and had poor fluidity during polymerization (Comparative Examples 1 and 2).

The melt viscosities of the aromatic polyesters of Examples 2 to 5 were (liquid crystal starting temperature + 50 ° C, shear rate 3000 (1 /
Seconds)), and had a good fluidity of 1000 to 5000 poise.

<Effect of the Invention> The aromatic polyester of the present invention can be melt-molded at 400 ° C. or lower, and has good fluidity, heat resistance, and mechanical properties typified by Izod impact strength. It can be used for precision molded products.

Claims (1)

(57) [Claims] 1. The following structural units (A) to (D), wherein the total of the structural units (A) and (B) is the structural unit (A),
40 to 90 mol% based on the total of (B) and (C), 60 to 10 mol% of the structural unit (C) based on the total of structural units (A), (B) and (C), and the structural unit (B) is 1 to 40 mol% with respect to the total of the structural units (A) and (B), the structural unit (C) and the structural unit (D) are substantially equimolar, and
A high-impact aromatic polyester having a logarithmic viscosity (measured at 60 ° C. in pentafluorophenol at a concentration of 0.1 g / dl) of 1.0 to 8.0 dl / g. O-Y-O (C) (Where X is It is 1 or more types chosen from, and Y shows either of the following-.