JPH08169961A - Heat-resistant polyester molding and its production - Google Patents

Abstract

PURPOSE: To obtain a molding which scarecely undergoes a longterm change in properties and is excellent in mechanical strengths, shape retentivity and heat resistance. CONSTITUTION: A polyester molding made of a composition containing a major amount of an aromatic dicarboxylic acid and/or its esterifiable derivative, 1-20mol%, based on the entire dicarboylic acid component, aliphatic dicarboxylic acid and/or its esterifiable derivative, 1-15mol%, based on the entire diol component, dihydroy compound represented by the formula (R1 is a 2-4C alkyl group and R2 , R3 , R4 and R5 are each hydrogen or a 1-4C alkyl group) and at least 85mol%, based on the total diol component, aliphatic diol containing ethylene glycol and/or its esterifiable derivative.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a polyester molded article having excellent heat resistance and a method for producing the same. More specifically, the present invention relates to a molded product which is excellent in aging resistance, is transparent, tough, and can be molded easily, and a method for producing the molded product.

[0002]

2. Description of the Related Art Polyester moldings, particularly ethylene terephthalate moldings, exhibit excellent transparency, light weight and hygiene in products represented by food containers.
It is used in a wide range of fields. However, in these applications, the molded article as described above largely exposes the drawbacks of the polyester molded article that the dimension change occurs after molding due to its weakness with time, and the brittleness reduces the impact resistance and the like. Many efforts have been made to improve this.

In order to improve the resistance to change with time, the thickness of the molded body is increased, the strength of the molded body is improved by increasing the number of layers, the crystallinity is improved by strengthening heat setting, and the residual stress and strain are relaxed by devising the shape of the container. In addition to ethylene terephthalate constituents, a method of blending a component having relatively low stress during molding such as butylene terephthalate to alleviate residual stress and strain during molding has been proposed. It was
As such a method, JP-A-2-30512,
JP-A-4-63836, JP-A-4-368433
As mentioned in the publication, thickening of the molded body, improvement of the strength of the molded body due to multi-layering leads to an increase in the amount of resin used, and strengthening the heat set or changing the shape of the container leads to a complicated molding process, Further, blending other components has drawbacks such as deterioration of transparency and difficulty in recycling.

[0004]

The present inventors believe that it is important to reduce the residual stress in the polymer structure during molding of the molded article in order to improve the change with time. As a result of extensive studies for solving the problem, a specific polyester resin composition was found to be able to solve the above-mentioned drawbacks, and the present invention has been achieved. The object is to obtain a transparent and easily molded product having a low stress and a glass transition temperature necessary for imparting dimensional stability.

[0005]

[Means for Solving the Problems] The above-mentioned object is based on the following (A) as a main component, and the following (B), (C), and
A polyester molded article characterized by comprising a composition containing (D), and (A), (B), (C), (D)
It is achieved by a method for producing a polyester molded article, which comprises using a composition containing (A) aromatic dicarboxylic acid and / or its ester-forming derivative (B) aliphatic dicarboxylic acid and / or its ester-forming derivative in 1 to 100 mol% of all dicarboxylic acid components
20 mol% (C) General formula

Embedded image (R ₁ is an alkyl group having 2 to 4 carbon atoms, R ₂ , R ₃ , R ₄
And R ₅ are independently hydrogen or an alkyl group having 1 to 4 carbon atoms) and a dihydroxy compound represented by total diol component 1
1 to 15 mol% in 00 mol% (D) Aliphatic diol containing ethylene glycol and / or its ester-forming derivative is a total diol component 1
85 mol% or more in 00 mol%

Hereinafter, the present invention will be described in detail. (A) Aromatic dicarboxylic acid (and / or) used in the present invention
Alternatively, the component constituting the ester-forming derivative thereof means a substantially linear copolyester containing a homopolymer of terephthalate. Examples of components include:
Aromatic dicarboxylic acids (and / or their ester-forming derivatives) such as terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, 2,5-dimethylterephthalic acid, 1,4-naphthalenedicarboxylic acid, biphenyldicarboxylic acid, etc. Is mentioned.

Examples of the component (B) aliphatic dicarboxylic acid (and / or ester-forming derivative thereof) include adipic acid, pimelic acid, azelaic acid, sebacic acid and the like (and / or The ester-forming derivative) and the like are mentioned, and the amount of the compound is 1 to 20 mol%, preferably 3 to 15 mol% in 100 mol% of all dicarboxylic acid components. If the amount of the compound is less than 1 mol%, the expected strength against aging resistance cannot be obtained, and if it exceeds 20 mol%, the crystallization rate of the polyester itself becomes small and it cannot be used as a molded product. .

(C) General formula

Embedded image (R ₁ is an alkyl group having 2 to 4 carbon atoms, R ₂ , R ₃ , R ₄
And R ₅ are independently hydrogen or an alkyl group having 1 to 4 carbon atoms). Examples of dihydroxy compound constituents include 9,9-bis- (4-hydroxyethoxyphenyl) -fluorene and 9,9-bis -(4-hydroxypropoxyphenyl) -fluorene, 9,9-bis- (4
-Hydroxybutoxyphenyl) -fluorene and the like are preferable, but 9,9-bis- (4-hydroxyethoxyphenyl) -fluorene is particularly preferable from the viewpoint of moldability and ease of polymerization. The amount of the dihydroxy compound represented by the general formula (1) of the polyester is 1 to 15 mol%, preferably 5 to 10 mol%. If the amount of the compound is less than 1 mol%, the expected heat resistance cannot be obtained, and if it exceeds 15 mol%, the crystallization rate of the polyester itself becomes small, and it cannot be used for a stretch molded product.

9,9-bis- (4-hydroxyethoxyphenyl) -fluorene is, for example, 9,9-bis-
It is obtained by adding ethylene oxide (hereinafter abbreviated as EO) to (4-hydroxyphenyl) -fluorene. At this time, a 2EO adduct obtained by adding one molecule of ethylene oxide to both hydroxyl groups of phenol, (9,9-bis- (4-hydroxyethoxyphenyl) -fluorene)
In addition to 3EO and 4EO
Impurities such as adducts may be contained. 3EO, 4EO
When the amount of such impurities as described above increases, the heat resistance of the polyester polymer decreases. At this time, the purity of the 2EO adduct may be 85% or more, preferably 95% or more.

Examples of 9,9-bis- (4-hydroxypropoxyphenyl) -fluorene and 9,9-bis- (4-hydroxybutoxyphenyl) -fluorene include:
It can be obtained by reacting 9,9-bis- (4-hydroxyphenyl) -fluorene with 3-chloro-propan-1-ol and 4-chloro-propan-1-ol, respectively, under alkaline conditions. The purity at this time may be 85% or more, and preferably 95% or more.

(D) As constituent components of the aliphatic diol containing ethylene glycol and / or its ester-forming derivative, in addition to ethylene glycol, diethylene glycol, polyethylene glycol, polymethylene glycol, tetramethylene glycol, 1,4- Examples include butanediol glycol and the like, and the amount of the compound is 85 mol% or more from the viewpoint of maintaining crystallinity.

The components (A) to (D) described above may each contain one type or two or more types.

The polyester composition comprising the above (A) to (D) of the present invention may be, for example, a melt polymerization method such as a transesterification method or a direct exchange method, a solution polymerization method, an interfacial polymerization method or a resin blending method. It can be produced by selecting an appropriate method from known methods. Examples of the catalyst for the polymerization include germanium dioxide, titanium tetrabutoxide, antimony trioxide, antimony acetate and the like, but germanium dioxide is more preferable because it has an excellent color tone and is safer for food hygiene. These reaction conditions may be the same as conventional ones, and known methods can be used.

Further, as a method for producing a molded article, a conventionally known method can be used except that the composition containing the above (A) to (D) is used. For example, vacuum, compressed air,
Vacuum pressure molding, press molding, blow molding and the like.

[0015]

INDUSTRIAL APPLICABILITY The polyester resin composition of the present invention is a product having good heat resistance, which is not easily affected by changes in physical properties due to aging and is excellent in mechanical strength, shape retention, etc., in applications such as food packaging materials. It is a very useful composition with good moldability without impairing transparency. The produced molded product can be used in a wide range including various-shaped containers such as biaxially stretched bottle containers.

[0016]

EXAMPLES The present invention will be specifically described with reference to the following examples. The glass transition temperature, shrinkage initiation temperature, and impact value of the compositions in the examples were measured by the methods described below. The present invention is not limited to these examples.

(1) Glass transition temperature Using a differential scanning calorimeter (DSC) manufactured by PERKIN-ELMER, about 10 mg of a sample was used, and the heating rate was 1
The glass transition temperature (Tg) at 0 ° C / min was adopted.
The glass transition temperature of the present invention means the glass transition start temperature (Tig) specified in JIS-K7121 in the temperature rising process of differential scanning calorimetry (DSC).

(2) Shrinkage onset temperature Using a thermomechanical analyzer (TMA) manufactured by Rigaku Denki Co., Ltd., a sample having a draw ratio of × 3.2 was pulled at a load of 10 g and a heating rate of 10 ° C./min. The shrinkage initiation temperature in the loading method was adopted.

(3) Impact value Using a graphic impact tester manufactured by Toyo Seiki Co., Ltd., the test height is a draw ratio x1.5 times film: 30 cm,
Stretching ratio x 3.2 times Film: Load at 20 cm, 6.5k
The energy value of crack generation at film breakage at 23 ° C. was adopted.

Method of preparing sample for evaluation A resin-like test piece having a diameter of 130 mm and a thickness of about 500 .mu.m was prepared by melting the resin at 270 to 290.degree. Stretching ratio shall be evaluated under two conditions: stretching (× 1.5 times), stretching (× 3.2 times)
And Preheat at 95 ℃ x 2 minutes, stretching speed 5m / mi
The film was stretched under the condition of n to obtain a film having a thickness of 5 to 100 μm. Then, heat setting treatment was performed at 120 ° C. for 30 seconds.

As the aging treatment condition for promoting the change with time, the film was left in the air at 40 ° C. × 65% RH × 1 week.

(Example 1) Dimethyl terephthalate 95
Parts by weight, dimethyl adipate 5 parts by weight, 9,9-bis- (4-hydroxyethoxyphenyl) -fluorene
10 parts by weight and 90 parts by weight of ethylene glycol were used as raw materials, and 0.025 parts by weight of calcium acetate was used as a catalyst. These were put into a reaction tank and gradually heated from 180 ° C. to 230 ° C. according to a conventional method with stirring. Transesterification was carried out. After extracting a predetermined amount of methanol out of the system, the polymerization catalyst germanium dioxide 0.01
5 parts by weight and trimethyl phosphate to prevent coloring
0.008 parts by weight was added, the temperature was raised and the pressure was gradually reduced, and the heating tank temperature was 280 ° C. and the degree of vacuum was 1 Torr or less while removing the generated ethylene glycol. While maintaining this condition, waiting for the increase in viscosity, the reaction was terminated when the torque applied to the stirrer reached a predetermined value, and the reaction product was extruded into water to obtain pellets. The pellets thus obtained are chipped with a cutter, and 220 ° C x 1
Solid phase polymerization was carried out under reduced pressure of 2 Hr × 5 Torr or less.

The glass transition temperature of this composition after solid state polymerization was 82 ° C. When the shrinkage initiation temperature of the stretched film after the heat setting treatment was measured according to the above-described evaluation sample preparation method, the temperature was 98 ° C., and the impact value (crack generation energy) was a draw ratio × 1.5 times: 1.8 J, The draw ratio was 3.2 times: 2.7J. After that, the measured values of the sample film which has been aged over time due to the aging treatment were 98 ° C., 1.6 J and 2.9 J, respectively. Table 1 shows the above measurement results.

Example 2 The physical properties before and after the change with time were evaluated in the same manner as in Example 1 except that the raw material composition ratio was changed as shown in Table 1. Table 1 shows the measurement results.

Comparative Examples 1 to 5 Physical properties before and after the change with time were evaluated in the same manner as in Example 1 except that the raw material composition ratio was changed as shown in Table 1. Table 1 shows the measurement results.

As is clear from Table 1, in Examples 1 and 2, even after the aging treatment, the brittleness was not detected in the portion having a low stretch ratio such as stretching, and the variation in strength depending on the stretch ratio was excellent. It can be seen that the physical properties are maintained. On the other hand, in Comparative Examples 1 to 5, weakening, amorphization and the like of the low draw ratio portion were observed due to aging, and impacts such as a reduction in impact resistance, deterioration of moldability and deterioration of thermal stability were exhibited. .

From the above, it can be seen that the composition according to the present invention has good stability with respect to aging, heat resistance and transparency, and is also excellent in moldability.

[Table 1]

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[Procedure amendment]

[Submission date] April 26, 1995

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0020

[Correction method] Change

[Correction content]

Method for preparing sample for evaluation A resin-like test piece having a diameter of 130 mm and a thickness of about 500 μm was prepared by melting the resin at 270 to 290 ° C. and vacuum press forming in an N ₂ atmosphere. Stretching ratio shall be evaluated under two conditions: stretching (× 1.5 times), stretching (× 3.2 times)
And Preheat at 95 ℃ x 2 minutes, stretching speed 5m / mi
The film was stretched under the condition of n to obtain a film having a thickness of 50 to 100 μm. Then, heat setting treatment was performed at 120 ° C. for 30 seconds.

Claims (4)

[Claims] 1. A polyester molded article comprising a composition containing the following (A) as a main component and further containing the following (B), (C), and (D). (A) aromatic dicarboxylic acid and / or its ester-forming derivative (B) aliphatic dicarboxylic acid and / or its ester-forming derivative in 1 to 100 mol% of all dicarboxylic acid components
20 mol% (C) General formula: (R ₁ is an alkyl group having 2 to 4 carbon atoms, R ₂ , R ₃ , R ₄
And R ₅ are independently hydrogen or an alkyl group having 1 to 4 carbon atoms) and a dihydroxy compound represented by total diol component 1
1 to 15 mol% in 00 mol% (D) Aliphatic diol containing ethylene glycol and / or its ester-forming derivative is a total diol component 1
85 mol% or more in 00 mol% 2. The polyester molded article according to claim 1, wherein the dihydroxy compound represented by the general formula (1) is 9,9-bis- (4-hydroxyethoxyphenyl) -fluorene. 3. When the polyester resin composition is molded to produce a polyester molded article, the polyester resin composition as described in (A). (B). (C).
A method for producing a polyester molded article, which comprises using a composition containing (D). 4. The method for producing a polyester molded article according to claim 3, wherein the dihydroxy compound represented by the general formula (1) is 9,9-bis- (4-hydroxyethoxyphenyl) -fluorene. .