JP2003137986A - Polyester resin and molded article made thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polyester resin having excellent impact resistance and flexibility and high transparency and heat-resistance and provide a molded article made of the polyester resin. SOLUTION: The polyester resin contains 25-75 mol% 2,6- naphthalenedicarboxylic acid and 25-75 mol% dimer acid based on the total dicarboxylic acid component and contains 1,4-cyclohexanedimethanol as a main diol component. The polyester resin has excellent impact resistance and flexibility and high transparency and heat-resistance and, accordingly, it is widely usable as extrusion molded articles and injection molded articles.

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 an extrusion molded article and an injection molded article, and more specifically, it is superior in impact resistance and flexibility to polyethylene terephthalate resin, and has transparency and heat resistance. The present invention relates to a polyester resin having the same, an extrusion molded article and an injection molded article made of 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, 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, since it contains a large amount of chlorine in the material, it is regarded as a problem as a source of dioxin during incineration,
Further, it is suspected that a phthalate ester and other plasticizers, which are added in a large amount to give flexibility, act as environmental hormones.

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 inventors have found that a transparent heat-resistant polyester resin having excellent flexibility can be obtained by using naphthalene dicarboxylic acid and dimer acid as main dicarboxylic acid components and 1,4-cyclohexanedimethanol as main 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 to obtain 2,6-naphthalenedicarboxylic acid 2 based on all dicarboxylic acid components.
It is achieved by a polyester resin characterized by being a polyester containing 5-75 mol% and 25-75 mol% dimer acid and having 1,4-cyclohexanedimethanol as a main diol component.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The dicarboxylic acid component used in the polyester resin of the present invention is 25 to 75 mol% of 2,6-naphthalenedicarboxylic acid based on the total dicarboxylic acid component.
And 25-75 mol% of dimer acid.
When the ratio of 2,6-naphthalenedicarboxylic acid is less than 25 mol%, heat resistance is lowered and it becomes difficult to obtain a solid polymer at room temperature (25 ° C.). On the other hand, when the proportion of dimer acid is less than 25 mol%, the flexibility of the obtained polyester resin decreases.

In the polyester resin of the present invention, a small amount of another dicarboxylic acid component may be used in addition to the above two kinds of dicarboxylic acids. Specifically, aliphatic dicarboxylic acids such as adipic acid, oxalic acid, malonic acid, succinic acid, azelaic acid and sebacic acid, aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid and diphenyldicarboxylic acid, cyclohexanedicarboxylic acid and the like. Examples thereof include alicyclic dicarboxylic acid. These may be used alone or in combination of two or more, but it is preferably 20 mol% or less of the total dicarboxylic acid component.

The diol component used in the polyester resin of the present invention is mainly 1,4-cyclohexanedimethanol, but a small amount of other glycol component may be used. Specific examples thereof include ethylene glycol, diethylene glycol, butanediol, neopentyl glycol, propylene glycol, hexamethylene glycol, polyalkylene glycol, and a bisphenol A or bisphenol S diethoxy compound. These may be used alone or in combination of two or more, but it is preferably 20 mol% or less of the whole diol component.

The polyester resin of the present invention comprises a raw material containing 2,6-naphthalenedicarboxylic acid, dimer acid and 1,4-cyclohexanedimethanol as main components, and a group consisting of antimony, titanium, germanium, tin and zinc. It is produced by an esterification reaction step, a liquid phase polycondensation reaction step, and if necessary, a solid phase polymerization reaction step, using at least one metal element-containing compound selected from the above as a catalyst.

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 carried out at a temperature of 50 to 300 ° C. under a reduced pressure of 10 to 650 Pa. 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. Of these, titanium compounds are preferable in terms of polymerization reaction rate. The polycondensation reaction catalyst is added as an aqueous solution or 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 0.80 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 40 ° C. or higher measured by a DSC (differential scanning calorimeter) at a temperature rising rate of 10 ° C./min.
It is more preferably 50 ° C. or higher. When the glass transition temperature is lower than 40 ° C., the obtained molded product is likely to be deformed even at room temperature and its heat resistance 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 1.3 MPa, more preferably less than 1.0 MPa. If the flexural modulus is 1.3 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.

[0021]

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

[0022]

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 is dissolved in a mixed solution of trifluoroacetic acid-d and deuterated chloroform in a ratio of 1: 1 (weight ratio), and tetramethylsilane is mixed as a standard product, and FT-N manufactured by Varian is manufactured.
It measured using MR (type 300MG).

(4) Flexibility (flexural modulus) After drying the polyester resin of the present invention, the width is 6.0 ± 0.4.
mm, height 13.0 mm, length 130 mm, bending-molded into a bending test piece and subjected to JIS K 7171 by a tensile tester (Tensilon model RTM-500 manufactured by Orientec Co., Ltd.).
It was measured according to. ○: Bending elastic modulus less than 1.3 MPa ×: Bending elastic modulus of 1.3 MPa or more

(5) Transparency (sheet haze) After drying the polyester resin of the present invention, it is melt-molded into a sheet having a thickness of 0.3 mm, and a haze meter (manufactured by Nippon Denshoku Co., Ltd.)
It was measured according to JIS K7105 with a haze meter 300A). ◯: Haze less than 1.0% x: Haze 1.0% or more

(6) 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 8 and Comparative Examples 1 to 8 Polyester Production Process In a stainless steel autoclave, the predetermined amounts of the dicarboxylic acid component and the diol component shown in Table 1 were used, and the glycol component and the acid component had a molar ratio of 1. Prepared to be 8 and 250
The esterification reaction was carried out at 300 ° C. and 300 kPa. After completion of the esterification reaction, a predetermined amount of titanium tetrabutoxide was added as a polycondensation catalyst, and the polycondensation reaction was carried out under a reduced pressure of 285 ° C. and 133 Pa. Titanium tetrabutoxide is 2. Added as a wt% glycol 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.

In Comparative Examples 1 and 5, a polymer in a solid state at room temperature could not be obtained, and the physical properties of molded articles could not be evaluated. Further, in Comparative Example 8, the polymer was easily crystallized, and the glass transition temperature was not found by DSC measurement.

[0031]

[Table 1]

[0032]

[Table 2]

Claims (2)

[Claims] 1. The total dicarboxylic acid component is 2,6-
A polyester resin comprising 25 to 75 mol% of naphthalenedicarboxylic acid and 25 to 75 mol% of dimer acid, and a polyester having 1,4-cyclohexanedimethanol as a main diol component. 2. Based on all dicarboxylic acid components, 2,6-
A molded article made of a polyester resin, which is a polyester containing 25 to 75 mol% of naphthalenedicarboxylic acid and 25 to 75 mol% of dimer acid and containing 1,4-cyclohexanedimethanol as a main diol component.