JP2003002957A - Polyester resin and molded product composed of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polyester resin having excellent flexibility, transparency and heat resistance and a molded product composed of the polyester resin. SOLUTION: This polyester resin is obtained from terephthalic acid as a main dicarboxylic acid component and ethylene glycol as a main diol component and further contains 40-55 wt.% of a polyol compound represented by the formula in the diol component. The molded product obtained from the polyester resin is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyester resin used for extrusion molded articles and injection molded articles, and more specifically, a polyester resin having superior impact resistance to polyethylene terephthalate resin and having transparency and heat resistance. And an extrusion-molded article and an injection-molded article comprising the same.

[0002]

2. Description of the Related Art Polyethylene terephthalate (hereinafter PE
A polyester resin represented by T) is widely used as a bottle, a film, a sheet and a fiber because it has excellent mechanical properties, heat resistance and chemical resistance. In addition, attention has been paid to its excellent transparency, and attempts have been made to use it as extrusion molded products such as corrugated sheets and tubes, and injection molded products such as cosmetic containers, beer glasses, and sundries. However, a general PET resin has high rigidity and is inferior in flexibility, and cannot be used for applications such as extrusion molded products and injection molded products which require flexibility.

On the other hand, a soft polyvinyl chloride resin is a typical resin having flexibility. The soft polyvinyl chloride resin is widely used as an extrusion-molded product such as a sheet, a film, and a tube as a resin having excellent flexibility, transparency, heat resistance, and moldability. However, apart from this excellent property, it is regarded as a problem as a dioxin source during garbage incineration because it contains a large amount of chlorine in the material. The action as an endocrine disrupter is also suspected on plasticizers such as acid esters.

As a flexible resin replacing the soft vinyl chloride resin, there is a polyolefin resin such as polyethylene or polypropylene. Although these resins have excellent flexibility, they cannot obtain the transparency required for extrusion molded products and injection molded products.

Further, JP-A-57-192452 and JP-A-3-252419 propose a flexible polyester resin obtained by copolymerizing dimer acid or dimer diol. The decrease in heat resistance due to the use of group compounds is unavoidable.

The present inventors have been working on the development of a polyester resin having excellent flexibility, transparency and heat resistance,
The present invention has been accomplished by discovering that a transparent heat-resistant polyester resin having excellent flexibility can be obtained by using a specific polyol compound as a diol component.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the prior art and to provide a polyester resin having excellent flexibility, transparency and heat resistance, and a molded article made of the same. is there.

[0008]

The above object is a polyester containing terephthalic acid as a main dicarboxylic acid component and ethylene glycol as a main diol component, wherein the polyol compound represented by the formula (3) is contained in the diol component. It is achieved by a polyester resin characterized by containing ~ 55% by weight.

[0009]

[Chemical 3] (R is an alkyl group)

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The polyester resin of the present invention is obtained by polycondensation by a conventionally known method with terephthalic acid as a main acid component, ethylene glycol as a main diol component, and a predetermined amount of a polyol compound. It is a thing.

The polyol compound contained in the polyester resin of the present invention contains a compound represented by the formula (4) as a main component, and the average molecular weight thereof is preferably 1000 to 1800, and preferably 1500 to 1800. Is more preferable. If the average molecular weight is less than 1000,
The obtained polyester has insufficient flexibility and heat resistance, and when the average molecular weight exceeds 1800, the transparency of the obtained polyester is lowered.

[0012]

[Chemical 4] (R is an alkyl group)

In the polyester resin of the present invention, the content of the polyol compound is 40 to 40 based on the total diol component.
55% by weight. When the content of the polyol compound is less than 40% by weight, the flexibility of the obtained polyester is not sufficient, and when it exceeds 55% by weight, the heat resistance of the obtained polyester is lowered.

The polyester resin of the present invention comprises a raw material comprising terephthalic acid or an ester-forming derivative thereof, ethylene glycol or a derivative thereof, and a polyol compound, and antimony, titanium, germanium, tin,
It is produced by using at least one metal element-containing compound selected from the group consisting of zinc as a catalyst, an esterification reaction step, a liquid phase polycondensation reaction step, a solid phase polymerization reaction step if necessary, and a heat treatment step.

The esterification reaction step is at 240 to 280 ° C.
At a pressure of 20-300 kPa. At this time, only water generated by the esterification reaction between terephthalic acid and the diol component is released out of the system. In this esterification reaction step, when a small amount of a basic compound is added, a polyester with few side reaction products is obtained. Examples of such basic compounds include triethylamine, tributylamine, benzylmethylamine and the like.
Examples thereof include quaternary amines such as secondary amines, tetraethylammonium hydroxide, tetrabutylammonium hydroxide, and trimethylbenzylammonium hydroxide.

The liquid phase polycondensation reaction step is carried out in the presence of at least one metal element-containing compound catalyst selected from the group consisting of antimony, titanium, germanium, tin and zinc.
It is performed under a reduced pressure of 13.3 to 665 Pa at a temperature of 50 to 300 ° C. In the liquid phase polycondensation reaction step, the unreacted diol component is distilled out of the system from the low-order condensate of terephthalic acid and the diol component obtained in the esterification reaction step.

Examples of the polycondensation reaction catalyst used in the present invention include germanium compounds such as germanium dioxide, germanium tetraethoxide and germanium tetrabutoxide, antimony compounds such as antimony trioxide, antimony pentoxide, antimony tartrate and antimony acetate.
Examples thereof include titanium compounds such as tetrabutyl titanate, tin compounds such as tin acetate, and zinc compounds such as zinc acetate. Among them, germanium compounds are preferable in terms of color tone and transparency of the obtained resin. The polycondensation reaction catalyst is added as an aqueous solution or ethylene glycol solution having a predetermined catalyst concentration.

In the liquid phase polycondensation reaction step, a stabilizer may be added to prevent side reactions such as thermal decomposition of the polyester resin. As a stabilizer, trimethyl phosphate,
Examples thereof include phosphoric acid esters such as triethylphosphoric acid and triphenylphosphoric acid, phosphorus compounds such as phosphorous acid and polyphosphoric acid, and hindered phenol compounds.

The intrinsic viscosity of the polyester resin obtained in the liquid phase polycondensation reaction step of the present invention is 0.40 to 0.70 dl.
/ G. If necessary, a polyester resin having an intrinsic viscosity of 0.60 to 1.00 dl / g can be obtained by solid phase polycondensation reaction. Solid phase polycondensation reaction is 180-2
At a temperature of 20 ° C, under reduced pressure or in an inert gas atmosphere, 5
~ 40 hours.

The polyester resin of the present invention preferably has a glass transition temperature of 50 ° C. or higher measured with a DSC (differential scanning calorimeter) at a temperature rising rate of 10 ° C./min.
It is more preferably 60 ° C. or higher. When the glass transition temperature is lower than 50 ° C, the heat resistance of the obtained molded product is insufficient.

The polyester resin of the present invention is JIS K
7171 “Plastics-Bending property test method” has a flexural modulus of preferably less than 1.5 MPa, more preferably less than 1.0 MPa. If the flexural modulus is 1.5 MPa or more, the flexibility is insufficient.

The polyester resin of the present invention is molded into an extrusion molded product and an injection molded product by a known method. For example, a sheet extruded product is obtained by supplying a polyester resin to a sheet extruding machine with a vent, extruding the polyester resin onto a sheet from a predetermined T die at a melting temperature of the resin, and cooling and solidifying with a cooling roll. Also, the injection molded product has a moisture content of 100 pp when dried on a polyester resin.
After being made m or less, it is supplied to an injection molding machine, injection-molded into a mold having a predetermined shape at the melting temperature of the resin, and then cooled and solidified in the mold to obtain the resin.

[0023]

The polyester resin of the present invention has excellent flexibility, and since it has transparency and heat resistance, it can be widely used as an extrusion molded product and an injection molded product.

[0024]

The present invention will be described in detail below with reference to examples. The measurement and evaluation of each physical property were according to the following methods.

(1) Intrinsic viscosity (IV) Polyester resin is phenol / tetrachloroethane =
Dissolve it in a mixed solution of 60/40 (weight ratio), and use an automatic viscosity measuring device (SS-270LC manufactured by Shibayama Kagaku) at 20 ° C.
It was measured at.

(2) Glass transition temperature It was measured at a temperature rising rate of 10 ° C./min using a DSC (differential scanning calorimeter) manufactured by Perkin Elmer.

(3) Determination of polyester constituents (NM
R measurement) A polyester resin was dissolved in a mixed solution of trifluoroacetic acid and chloroform at a ratio of 1: 1 (weight ratio), and tetramethylsilane was mixed as a standard product, and FT-NMR manufactured by Varian.
(Model 300MG).

(4) Flexibility (flexural modulus) After drying the polyester resin of the present invention, the width is 6.0 ± mm,
A bending test piece having a height of 13.0 mm and a length of 130 mm was melt-molded and measured by a bending tester (TENSILON model RTM-500 manufactured by Orientec Co., Ltd.) according to JIS K7171. ○: Bending elastic modulus less than 1.5 MPa ×: Bending elastic modulus of 1.5 MPa or more

(5) Transparency (Plate haze) After drying the polyester resin of the present invention, it is melt-molded on a flat plate having a thickness of 6 mm, and JIS K7105 is measured by a haze meter (Haze meter 300A manufactured by Nippon Denshoku Co., Ltd.).
It was measured according to. ◯: Haze less than 1.0% x: Haze 1.0% or more

(6) Heat resistance (heat distortion temperature) After drying the polyester resin of the present invention, the width is 6.0 ± mm,
Melt-molded into a bending test piece with a height of 13.0 mm and a length of 130 mm, and use a load deflection temperature tester (heat distortion tester model S3-MH manufactured by Toyo Seiki Seisakusho)
It was measured according to IS K7207. (Temperature increase rate 120
° C / hour, load 45.1 N / cm ² ) ◯: Heat distortion temperature of 50 ° C or higher. X: Heat distortion temperature of less than 50 ° C.

(7) Impact resistance (Izod impact strength) After drying the polyester resin of the present invention, the thickness is 6.35 mm.
It was melt-molded into an Izod impact test piece and measured by an Izod impact tester (UF impact tester manufactured by Ueshima Seisakusho) according to JIS K7110.

Examples 1 to 4 and Comparative Examples 1 to 4 Polyester Production Process In a stainless steel autoclave, the predetermined amounts of the terephthalic acid component and ethylene glycol shown in Table 1 were used. Prepared to be 2,
Further, by adding a predetermined amount of the polyol compound,
The esterification reaction was performed at 300 kPa. After completion of the esterification reaction, a predetermined amount of germanium dioxide was added as a polycondensation catalyst, and the polycondensation reaction was carried out under a reduced pressure of 285 ° C. and 133 Pa. Germanium dioxide was added as a 0.8% by weight aqueous solution. The polyester after the polycondensation reaction was extruded into a gut shape and then cut using an underwater cutter.
Tables 1 and 2 show the composition and physical property evaluation results of the obtained polyester resin analyzed by NMR.

[0033]

[Table 1]

[0034]

[Table 2]

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 4F071 AA47 AF20 AF23 AF30 AF45                       AH19 BA01 BB05 BB06 BC01                       BC07 BC17                 4J029 AA03 AB01 AB07 AC02 AE01                       AE03 BA03 BF26 CB06A                       JA091 JA253 JB131 JB171                       JB193 JC413 JC453 JE182                       JF321 JF361 JF371 JF471

Claims (2)

[Claims] 1. A polyester comprising terephthalic acid as a main dicarboxylic acid component and ethylene glycol as a main diol component, wherein the diol component contains 40 to 55% by weight of the polyol compound represented by the formula (1). Characteristic polyester resin. [Chemical 1] (R is an alkyl group) 2. A polyester resin containing terephthalic acid as a main dicarboxylic acid component and ethylene glycol as a main diol component, wherein the diol component contains 40 to 55% by weight of the polyol compound represented by the formula (2). A molded product consisting of. [Chemical 2] (R is an alkyl group)