JP2590585B2 - Copolyester resin - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial application field> The present invention provides a polymer having a high degree of polymerization by melt polymerization alone, exhibits excellent liquid crystallinity, and has excellent mechanical properties, especially improved properties, which can be molded by a usual molding machine. The present invention relates to a copolymerized polyester having a high weld strength.

<Prior art> In recent years, there has been an increasing demand for higher performance plastics, and many polymers having various novel properties have been developed. Among them, optically anisotropic liquid crystal polymers have excellent mechanical properties. (JP-A-51-8395)
JP, JP-A-49-72393).

As the liquid crystal polymer, for example, a liquid crystal polymer obtained by copolymerizing p-hydroxybenzoic acid with polyethylene terephthalate is known (JP-A-49-72393). However, injection moldings of this polymer have the disadvantages of insufficient heat resistance and poor mechanical properties, and it has been found that injection moldings satisfying both properties cannot be obtained from this polymer. In addition, p-
Needs more than 80 mol% of hydroxybenzoic acid,
At this time, it was found that solidification occurred during polymerization, and that solid-phase polymerization was necessary.

On the other hand, as a means for improving the flowability of such a polymer, improving the melt moldability, and further improving the mechanical properties, for example, as described in JP-A-51-8395, polyethylene A method has been proposed in which terephthalate is copolymerized with p-acyloxybenzoic acid, a dicarboxylic acid and an aromatic diol. In this method, however, the mechanical properties of the injection molded product obtained are improved but the heat resistance is insufficient. I understand. On the other hand, as described in JP-B-47-47870, p-hydroxybenzoic acid
Injection molded products of wholly aromatic polyesters obtained by copolymerizing 4,4'-dihydroxybiphenyl and terephthalic acid have good heat resistance, but have a softening temperature of 400 ° C or higher, which makes melt polymerization difficult, resulting in mechanical properties. It turned out not to be very satisfactory.

As a method for solving these problems, Japanese Patent Application Laid-Open
A polymer obtained by copolymerizing p-hydroxybenzoic acid, a specific aromatic dihydroxy compound and an aromatic dicarboxylic acid with polyethylene terephthalate described in JP-A-63-30523 is satisfactory, although the balance between mechanical properties and heat resistance can be satisfied. It has been found that there remains a problem that the mechanical properties of the product, particularly the strength of the weld portion is slightly low.

<Problems to be Solved by the Invention> The present invention solves the above-mentioned problems, and is excellent in a balance between mechanical properties and heat resistance, and in particular, can provide a molded article having improved weld part strength. It is an object to obtain a resin.

<Means for Solving the Problems> Accordingly, the present inventors have conducted intensive studies to achieve the above object, and as a result, have found that p-hydroxybenzoic acid, 4,4'-dihydroxybiphenyl, a specific aromatic dihydroxy compound, an aromatic dicarboxylic acid, A copolymer obtained by reacting an acid or ethylene glycol with a polyester formed from an aromatic dicarboxylic acid is further reacted with at least one compound selected from aromatic compounds having a trifunctional or tetrafunctional ester-forming reactive group. The present inventors have found that the above objects can be achieved by copolymerization, and have reached the present invention.

That is, the present invention provides the following structural units (I), (II),
(III), (IV) and the following structural units (V), (VI)
Is obtained by copolymerizing at least one structural unit obtained from the polyfunctional compound represented by the formula (1), wherein the total of the structural units (V) and (VI) is structural units (I), (II), (III),
The present invention relates to a copolymerized polyester resin which occupies 0.01 to 5 mol% with respect to the sum of (V) and (VI), and has a logarithmic viscosity of 0.5 to 15 dl / g.

_{O-R 1 -O ... (III} ) CO-R 2 -CO ... (IV) (However, R ₁ in the formula (III) is -CH ₂ CH _2- or -CH ₂
CH ₂ − and and Represents one or more groups selected from Also, in equation (IV)
R ₂ And one or more groups selected from Here, Y represents a chlorine atom or a hydrogen atom. Ar ₁ represents a 3-substituted aromatic residue, and Ar ₂ represents a 4-substituted aromatic residue. X ₁ , X ₂ , X
₃ , X ₄ , X ₅ , X ₆ and X ₇ are each independently a polyester-forming -O- or Is shown. The present invention also provides a molded article comprising the above-mentioned copolymerized polyester resin as an essential component and the above-mentioned molded article wherein the molded article has a weld portion.

Further, the present invention provides the following (A) to (C) and (D) to
(E) reacting with acetic anhydride in the presence of the following (F) in the presence of the following (F) to acetylate the hydroxyl group, followed by a deacetic acid polycondensation reaction to produce the above-mentioned copolymerized polyester resin. This is a method for producing a copolymerized polyester resin.

(A) p-hydroxybenzoic acid (B) (b-1) 4,4'-dihydroxybiphenyl or (b-2) 4,4'-dihydroxybiphenyl, hydroquinone, 2,6-dihydroxynaphthalene, 4 1,4'-dihydroxydiphenyl ether, t-butylhydroquinone, phenylhydroquinone, 3,3 ', 5,5'-tetramethyl-4,4'-dihydroxybiphenyl
(C) terephthalic acid, isophthalic acid, 4,4'-diphenyldicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 1,2-
Bis (phenoxy) ethane-4,4'-dicarboxylic acid, 1,2
At least one aromatic dicarboxylic acid selected from -bis (2-chlorophenoxy) ethane-4,4'-dicarboxylic acid and 4,4'-diphenyletherdicarboxylic acid; (D) an aromatic having a trifunctional polyester-forming reactive group. Group compounds (E) Aromatic compounds having a tetrafunctional polyester-forming reactive group (F) Terephthalic acid, isophthalic acid, 4,4'-diphenyldicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 1,2-
Bis (phenoxy) ethane-4,4'-dicarboxylic acid, 1,2
One or more aromatic dicarboxylic acids selected from one or more aromatic dicarboxylic acids selected from -bis (2-chlorophenoxy) ethane-4,4'-dicarboxylic acid and 4,4 'diphenyl ether dicarboxylic acid and ethylene glycol The reaction of a liquid crystal polyester with a polyfunctional compound having three or more reactive functional groups is disclosed in JP-A-62-70419. However, this is the purpose of adding a large amount of polyfunctional compound to the liquid crystal polyester and reacting to cross-link and fix the liquid crystal polyester. It is completely different from the present invention in that the addition enhances the weld strength without impairing the flowability of the liquid crystal polyester. Things.

The structural unit (I) is a structural unit of a polyester formed from (A) p-hydroxybenzoic acid, and the structural unit (II) is a structural unit formed from (B) 4,4'-dihydroxybiphenyl. (III) is ethylene glycol, or ethylene glycol and hydroquinone,
2,6-dihydroxynaphthalene, 4,4'-dihydroxydiphenyl ether, t-butylhydroquinone, phenylhydroquinone, 3,3 ', 5,5'-tetramethyl-4,4'
-A structural unit formed from one or more dihydroxy compounds selected from dihydroxybiphenyl, and the structural unit (IV) is terephthalic acid, isophthalic acid, 4,4'-diphenyldicarboxylic acid, 2,6-naphthalenedicarboxylic acid,
1,2-bis (phenoxy) ethane-4,4'-dicarboxylic acid, 1,2-bis (2-chlorophenoxy) ethane-4,4 '
And structural units formed from one or more aromatic dicarboxylic acids selected from -dicarboxylic acid and 4,4'-diphenyletherdicarboxylic acid.

Of these, R ₁ is -CH ₂ CH _2- , and R ₂ is Is particularly preferred.

Further, the structural unit (V) is a structural unit generated from an aromatic compound having a trifunctional polyester-forming reactive group, and Ar ₁ represents a tri-substituted aromatic residue, tri-substituted benzene, tri-substituted naphthalene, Examples include trisubstituted biphenyl and the like.

Examples of the polyester-forming reactive group of the compound constituting the structural unit (V) include a hydroxyl group, an acetoxy group, a carboxyl group, and a carboxyphenyl group.
A compound in which two adjacent carboxyl groups form an acid anhydride can also be preferably used.

Preferred specific examples of the compound having a trifunctional polyester-forming reactive group constituting the structural unit (V) include trimellitic acid, trimesic acid, hemimellitic acid, trimellitic anhydride, hemimellitic anhydride, -Hydroxyisophthalic acid, 2,3-dihydroxybenzoic acid, 2,4-dihydroxybenzoic acid, 2,5-dihydroxybenzoic acid, 2,6
-Dihydroxybenzoic acid, 1,2,4-benzenetriol, 1,4-dihydroxy-2-naphthoic acid, 3,5-dihydroxy-2-naphthoic acid, 3,7-dihydroxy-2-naphthoic acid and ester derivatives thereof And the like.

Structural unit (VI) is a structural unit generated from an aromatic compound having a tetrafunctional polyester-forming reactive group, and Ar ₂ represents a tetrasubstituted aromatic residue, and is represented by tetrasubstituted benzene, tetrasubstituted naphthalene, Examples include 4-substituted biphenyl.

The polyester-forming reactive group of the compound providing the structural unit (VI) is the same as in the case of the structural unit (V). Preferred specific examples of the compound providing the structural unit (VI) include pyromellitic acid, 1,4 , 5,8-Naphthalenetetracarboxylic acid, 3,4,3 ', 4'-biphenyltetracarboxylic acid and acid anhydrides and ester derivatives thereof.

On the other hand, among the above structural units, the total of the structural units (V) and (VI) is the sum of the structural units (I), (II), (III),
(V) and (VI) should be 0.1-5 mol%). Structural unit (V)
And the sum of (VI) is the structural unit (I), (II), (II)
If the total amount of I), (V) and (VI) is less than 0.01 mol, the effect of the present invention is not remarkable, and the improvement in weld strength is not sufficient. Also, if it is more than 5 mol%,
Either case is not preferable because the melt fluidity tends to decrease.

The sum of the structural units (I) and (II) is (I),
It is preferably from 75 to 95 mol%, more preferably from 82 to 93 mol%, particularly preferably from 85 to 90 mol%, based on the total of (II) and (III).

The structural units (III) are represented by (I), (II) and (II)
It is preferably from 25 to 5 mol%, more preferably from 18 to 7 mol%, particularly preferably from 15 to 10 mol%, based on the total of I).

Further, the molar ratio of the structural units (I) and (II) [(I) /
(II)] is preferably 75/25 to 95/5, more preferably 78/22 to 93/7.

Also, the sum of the structural units (II) and (III) [(II)
+ (III)] and the structural unit (IV) are preferably substantially equimolar, but in the present invention, since an aromatic compound having a trifunctional or tetrafunctional ester-forming reactive group is copolymerized, The polymerization may be performed at a composition ratio as shown in the following formula.

0.9 <[(II) + (III)] / (IV) <1.1 The method for producing the copolymerized polyester resin of the present invention is not particularly limited, and it can be produced according to a known polyester polycondensation method. For example, in the presence of a polyester or oligomer composed of an aromatic dicarboxylic acid such as terephthalic acid and ethylene glycol, or an bis (β-hydroxyethyl) ester of an aromatic dicarboxylic acid (F),
-Hydroxybenzoic acid (A), aromatic hydroxy compound (B) such as 4,4'-dihydroxybiphenyl, aromatic dicarboxylic acid (C) such as terephthalic acid, and trifunctional or tetrafunctional such as trimellitic anhydride. A particularly preferable example is a method in which acetic anhydride is allowed to act on the aromatic compounds (D) to (E) having a polyester-forming reactive group to acetylate a hydroxyl group, followed by a deacetic acid polycondensation reaction.

A catalyst may be used for the polycondensation reaction, and examples thereof include metal compounds such as stannous acetate, tetrabutyl titanate, potassium acetate, antimony trioxide, magnesium, and sodium acetate.

The melt viscosity of the copolymerized polyester resin of the present invention is 10
〜15,000 poise is preferred, and 20-5,000 poise is more preferred.

The melt viscosity is a value measured by a Koka type flow tester under the condition of a liquid crystal start temperature + 40 ° C. and a shear rate of 1,000 (1 / second).

On the other hand, the logarithmic viscosity of the copolymerized polyester resin of the present invention is
The value measured in pentafluorophenol at a concentration of 0.1 g / dl and 60 ° C. is 0.5 to 15 dl / g. The structural unit (II
When I) contains —CH ₂ CH ₂ — as R ₁ , it is 1.0 to 3.0 d
l / g is preferred.

In the polycondensation of the copolymerized polyester resin of the present invention, 3,3′-diphenyldicarboxylic acid and 2,2′-diphenyldicarboxylic acid other than the components constituting the structural units (I) to (IV) are used. Aromatic dicarboxylic acids such as aromatic dicarbanoic acid, adipic acid, azelaic acid, sebacic acid, dodecanedioic acid, alicyclic dicarboxylic acids such as hexahydroterephthalic acid, chlorohydroquinone, aromatic dihydroxy compounds such as methylhydroquinone, 1,4-
Aliphatic, alicyclic diols such as butanediol, 1,6-hexanediol, neopentyl glycol, 1,4-dichlorohexanediol, 1,4-cyclohexanedimethanol, and m-hydroxybenzoic acid, 2,6-hydroxy An object of the present invention is to provide an aromatic hydroxycarboxylic acid such as naphthoic acid and an aromatic imide dicarboxylic acid, an aromatic imide dihydroxy compound, an aromatic imide hydroxy carboxylic acid, etc., having an imide bond in the molecule and capable of forming a polyester. Can be further copolymerized within a small proportion that does not impair the above.

The copolymerized polyester resin of the present invention thus obtained can obtain a polymer having a high degree of polymerization only by melt polymerization, and exhibits excellent melt fluidity, excellent mechanical properties with improved weld strength and heat resistance, and is extruded and injection-molded. It can be subjected to ordinary melt molding such as compression molding, blow molding, etc., and can be processed into fibers, films, three-dimensional molded products, containers and hoses.

In addition, with respect to the copolyester resin of the present invention, glass fiber, carbon fiber, reinforcing agents such as asbestos, fillers, lubricants, release agents, nucleating agents, plasticizers, flame retardants, heat stabilizers, ultraviolet absorbers, pigments , Dyes and other thermoplastic resins can be added as needed to impart desired properties.

Fillers, additives to the copolymerized polyester resin of the present invention,
Means for compounding a reinforcing agent or the like is optional, but for example, a screw extruder or the like can be preferably used.

In addition, the strength of the injection-molded article obtained in this manner can be increased by heat treatment, and the elastic modulus can also be increased in some cases.

This heat treatment can be performed by heat treating the injection molded article in an inert atmosphere (eg, nitrogen, argon, helium, or water vapor) or an oxygen-containing atmosphere (eg, air) at a temperature equal to or lower than the melting point of the polymer. This heat treatment may or may not be under tension and can take place in tens of minutes to several days.

<Example> Hereinafter, the present invention will be further described with reference to examples.

Example 1 In a reaction vessel equipped with a stirrer and a distilling tube, 994 g (7.2 mol) of p-hydroxybenzoic acid, 134 g (0.72 mol) of 4,4'-dihydroxybiphenyl, 112 g (0.675 mol) of terephthalic acid, and 970 g of acetic anhydride (9.5 mol), 216 g (1.125 mol) of polyethylene terephthalate having an intrinsic viscosity of about 0.6 and 8.64 g (0.045 mol) of trimellitic anhydride were subjected to deacetic acid polymerization under the following conditions.

First, under nitrogen atmosphere, 100 ~ 250 ℃ for 5 hours, 250 ~ 3
After reacting at 20 ℃ for 1.5 hours, 0.5mmHg at 320 ℃ for 1 hour
The reaction was further reduced for 1.0 hour to complete the polycondensation. As a result, an almost theoretical amount of acetic acid was distilled off, and a polymer having the following theoretical structural formula was obtained.

k / l / m / n / o = 80/8 / 12.5 / 20 / 0.5 The polyester was placed on a sample stage of a polarizing microscope and the temperature was raised to confirm the optical anisotropy. Was 283 ° C., showing good optical anisotropy.

The obtained polymer is supplied to Sumitomo Nestal injection molding machine Promat 40/25 (manufactured by Sumitomo Heavy Industries, Ltd.), and the cylinder temperature is 320 ° C. and the mold temperature is 90 ° C., 1/8 ″ × 1/2. ″ ×
5 "test pieces and ASTM No. 4 dumbbells were molded. ASTM No. 4 dumbbells consist of a standard mold (dumbbell I) with a gate at one end of the dumbbell and a weld mold (dumbbell) with gates at both ends of the dumbbell. The molded article was molded using both of the above two methods, and the deflection temperature under load [HDT] (18.6 kgf / cm ² ) of a 1/8 ″ thick test piece was measured in accordance with the ASTM D648 standard. In addition, the breaking strength of ASTM No. 4 dumbbell was measured according to the ASTM D638 standard, and the dumbbell against dumbbell I was measured.
The ratio of the breaking strength of II was defined as the weld strength retention.

As a result, HDT226 ° C, strength of dumbbell I (non-weld) 1120 kgf / cm ² , strength of dumbbell II (weld) 195 kg
f / cm ² , and the weld strength retention was 17.4%.

The logarithmic viscosity of this polymer (in pentafluorophenol at 60 ° C.) is 1.92 dl / g, and the melt viscosity is a shear rate of 1,000.
The fluidity was very good at 1900 poise (1 / sec).

Comparative Example 1 An experiment similar to that of Example 1 was performed on a polymer having a composition not containing the structural units (V), (VI), and (VII) in the present invention.

In a reaction vessel similar to that in Example 1, 994 g (7.2 mol) of p-hydroxybenzoic acid and 4,4'-dihydroxybiphenyl 12
6 g (0.675 mol), 960 g (9.4 mol) of acetic anhydride, 112 g (0.675 mol) of terephthalic acid and 216 g (1.125 mol) of polyethylene terephthalate having an intrinsic viscosity of about 0.6 were charged. A polymer having the following theoretical structural formula was obtained.

k / l / m / n = 80 / 7.5 / 12.5 / 20 Also, as a result of placing this polyester on a sample stage of a polarizing microscope and raising the temperature to check the optical anisotropy, the liquid crystal onset temperature was 294 ° C. there were.

This polymer was molded in the same manner as in Example 1 to obtain an HD.
A result of measuring the T and breaking strength, HDT231 ℃, the strength of the dumbbell I (non-weld) 1200kgf / cm ^2, the intensity of the dumbbell II (Weld) 150kgf / cm ^2, weld strength retention in Examples and 12.5% It turned out to be lower than that.

<Effect of the Invention> The polymerized polyester of the present invention can obtain a polymer having a high degree of polymerization only by a melt polymerization method. From this polymer, the heat resistance and the mechanical properties are excellently balanced, and the mechanical properties, particularly the strength of the weld portion, are improved. Since a molded article can be obtained, it can be used for various applications such as a metal substitute plastic.

Claims (4)

(57) [Claims] 1. The following structural units (I), (II), (III),
(IV) and at least one structural unit obtained from the polyfunctional compound represented by the following structural units (V) and (VI) are copolymerized, and the total of the structural units (V) and (VI) is Units (I), (II), (III), (V) and (V)
Copolymerized polyester resin having a logarithmic viscosity of 0.5 to 15 dl / g in an amount of 0.01 to 5 mol% based on the total of I). _{O-R 1 -O ... (III} ) CO-R 2 -CO ... (IV) (However, R _{1 in} (III) is -CH ₂ CH _2- or -CH ₂ CH
₂ -and and And one or more groups selected from R ₂ in the formula (IV) is Represents one or more groups selected from Here, Y represents a chlorine atom or a hydrogen atom. Ar ₁ represents a 3-substituted aromatic residue, and Ar ₂ represents a 4-substituted aromatic residue. X ₁ , X ₂ ,
X ₃ , X ₄ , X ₅ , X ₆ and X ₇ are each independently a polyester-forming -O- or Is shown. ) 2. A molded article comprising the copolymerized polyester resin according to claim 1 as an essential component. 3. The molded article according to claim 2, wherein the molded article has a weld portion. 4. A hydroxyl group is acetylated by reacting the following (A) to (C) and one or more selected from (D) to (E) with acetic anhydride in the presence of the following (F): 2. A method for producing a copolymerized polyester resin according to claim 1, wherein the copolymerized polyester resin according to claim 1 is produced by a subsequent deacetic acid polycondensation reaction. (A) p-hydroxybenzoic acid (B) (b-1) 4,4'-dihydroxybiphenyl or (b-2) 4,4'-dihydroxybiphenyl, hydroquinone, 2,6-dihydroxynaphthalene, 4 1,4'-dihydroxydiphenyl ether, t-butylhydroquinone, phenylhydroquinone, 3,3 ', 5,5'-tetramethyl-4,4'-dihydroxybiphenyl
(C) terephthalic acid, isophthalic acid, 4,4'-diphenyldicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 1,2-
Bis (phenoxy) ethane-4,4'-dicarboxylic acid, 1,2
At least one aromatic dicarboxylic acid selected from -bis (2-chlorophenoxy) ethane-4,4'-dicarboxylic acid and 4,4'-diphenyletherdicarboxylic acid; (D) an aromatic having a trifunctional polyester-forming reactive group. Group compounds (E) Aromatic compounds having a tetrafunctional polyester-forming reactive group (F) Terephthalic acid, isophthalic acid, 4,4'-diphenyldicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 1,2-
Bis (phenoxy) ethane-4,4'-dicarboxylic acid, 1,2
One or more aromatic dicarboxylic acids selected from one or more aromatic dicarboxylic acids selected from -bis (2-chlorophenoxy) ethane-4,4'-dicarboxylic acid and 4,4 'diphenyl ether dicarboxylic acid and ethylene glycol Or a bis (β-hydroxyethyl) ester of the aromatic dicarboxylic acid