JP2000017065A - Polyester composition and film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a polyester compsn. with no contaminant and good color and excellent in moldability, light resistance, gas barrier property, and a film therefrom. SOLUTION: This polyester compsn. comprises 2,6-naphthalene dicarboxylic acid as a main dicarboxylic acid component and 1,3-propanediol as a main glycol component and is obtained by polymerization using a Ti compd. as a polymerization catalyst, and the purity of dicarboxylic acid component is not less than 99.5%, and retention of the Ti compd. in this polyester compsn. is 15-300 ppm as Ti atomic wt. equivalent, and L value and (b) value measured by Lab method satisfy the equations I and II shown below. Equation I: 65<=L-b. Equation II: b<=10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a polyester composition and a film. More specifically, the present invention relates to a polyester composition and a film which contain little foreign matter in polyester and have excellent moldability, light resistance and gas barrier properties.

[0002]

2. Description of the Related Art Polyesters represented by polyethylene terephthalate have excellent mechanical properties, heat resistance, weather resistance, electrical insulation resistance, and chemical resistance, and are widely used as films, fibers, bottles and other molded products. I have. Such polyesters have different required properties in each application, but in the production of aromatic polyesters, a polycondensation catalyst is necessary for smoothly proceeding the reaction, and various metal compounds have been proposed as polycondensation catalysts. . Above all, Sb compounds such as antimony trioxide are widely used as catalysts which are inexpensive and have high polymerization activity. However, these catalysts also have a problem, and the Sb compound is reduced to the metal S
b and other foreign substances, causing the polymer to darken,
It deteriorates the process condition and the quality of the molded product. Various studies have hitherto been made on the reduction of foreign substances in polymers using an Sb compound for these polycondensation catalysts. For example, JP-A-1-275628, JP-A-2-34
No. 20 proposes that an Sb compound is added as a catalyst for both transesterification and polycondensation in the early stage of transesterification reaction with a transesterification polymer, and the amount of polymer in the polymer is reduced by the amount that no other transesterification catalyst is added. It is described that the amount of foreign matter is reduced. However, according to the study of the present researcher, the polymer obtained by such a polymerization method has a low effect on the number of foreign substances caused by the Sb compound used as the polymerization catalyst and has little effect on coloring, and a polymer of good quality is obtained. Things are difficult. JP-A-61-231025 proposes a technique in which an Sb compound is used as a polycondensation catalyst and a small amount of terephthalic acid is added in the latter half of the polymerization to reduce foreign substances deposited on a spinneret during spinning. However, even if this technique is used, foreign matters in the polymer are not sufficiently reduced, and it is difficult to obtain good polymer quality. Further, JP-A-54-3939
0, Japanese Patent Application Laid-Open No. 60-67529 discloses a proposal in which a mixture of an Sb compound and a phosphorus compound which has been heated and mixed under appropriate conditions in advance is used as a polycondensation catalyst. This effect also reduces foreign matter in a spinneret during spinning. Therefore, the effect of reducing foreign matters in the polymer cannot be expected.

[0003]

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 composition which is free of foreign matter, has a good hue, and is excellent in moldability, light resistance and gas barrier properties. And a film comprising the same.

[0004]

As a result of intensive studies on these problems, a specific polyester is used as the polyester resin, a Ti compound is used as the polymerization catalyst, and the purity of the dicarboxylic acid component to be used is used. By controlling the above, it was found that a molded product using the resin composition had less surface defects and had a better hue than ever before, and the present invention was achieved. That is, an object of the present invention is a polyester composition polymerized using 2,6-naphthalenedicarboxylic acid as a main dicarboxylic acid component, 1,3-propanediol as a main glycol component, and a Ti compound as a polymerization catalyst. The purity of the dicarboxylic acid component is 99.5% or more, and the residual amount of the Ti compound in the polyester composition is 15 to
L is 300 ppm and measured by the Lab method.
This is achieved by a polyester composition and a film comprising the polyester composition, wherein the values and b satisfy the following formulas (1) and (2). 65 ≦ L−b (1) b ≦ 10 (2)

Hereinafter, the present invention will be described. The polyester used in the present invention is a polyester containing 2,6-naphthalenedicarboxylic acid as a main acid component and 1,3-propanediol as a main glycol component.

As the dicarboxylic acid component used in the present invention, dimethyl 2,6-naphthalenedicarboxylate is usually preferably used. In the present invention, the purity of the dicarboxylic acid component needs to be 99.5% or more. . Usually, dimethyl 6-formyl-2-naphthoate is often contained as an impurity in dimethyl 2,6-naphthalenedicarboxylate. However, the inclusion of this impurity causes end-blocking during polymerization. There is a problem that the speed is reduced and the hue is reduced as a result. This 2,6-
The purity of the naphthalenedicarboxylic acid component is preferably at least 99.7%, more preferably at least 99.8%.

In the polyester of the present invention, 2,6-
As a dicarboxylic acid other than naphthalenedicarboxylic acid, 2
In a range of 0 mol% or less, preferably 15 mol% or less, for example, terephthalic acid, isophthalic acid, phthalic acid, 2,7-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 4,4′-diphenylcarboxylic acid, , 2-bis (2-chlorophenoxy) ethane-4,4'-dicarboxylic acid, phenylenedioxydiacetic acid, bis (4-carboxymethoxyphenyl) sulfonic acid and other aromatic dicarboxylic acids or ester-forming derivatives thereof, succinic acid Adipic acid, an aliphatic dicarboxylic acid such as sebacic acid or an ester-forming derivative thereof, an alicyclic dicarboxylic acid such as cyclohexanedicarboxylic acid or an ester-forming derivative thereof, hydroxyacetic acid, oxycarboxylic acid such as 3-hydroxypropionic acid, or It has not been found that such ester-forming derivatives can be used as copolymer components. That. As the ester-forming derivative of the dicarboxylic acid, an ester with a lower alcohol such as methanol or ethanol is generally used, but an ester with a glycol such as ethylene glycol may be used.

The dicarboxylic acid component other than the 2,6-naphthalenedicarboxylic acid is not added to the impurities of the dicarboxylic acid component as long as it is used as a copolymer component, and therefore, a dicarboxylic acid component which lowers the purity of the dicarboxylic acid component. is not.

In the polyester of the present invention, 1,3-
As a glycol component other than propanediol, a range of 20 mol% or less, preferably 15 mol% or less, for example, ethylene glycol, 1,2-propanediol, tetramethylene glycol, hexamethylene glycol, neopentyl glycol, cyclohexane dimethanol, octane Aliphatic glycols such as methylene glycol, 1,4
Alicyclic glycols such as cyclohexane dimethanol,
Aromatic glycols such as 1,3-bis (β-hydroxyethoxy) benzene, bis (β-hydroxyethoxy) bisphenol S, bisphenol A and hydroquinone, and high molecular glycols such as polyethylene glycol and polypropylene glycol are used as copolymer components. You can do it.

[0010] The polyester of the present invention is usually prepared by diesterification of dicarboxylic acid with glycol, ester exchange reaction of dialkyl dicarboxylate with glycol, or reaction of dicarboxylic acid with alkylene oxide. To form a glycol ester and / or a low polymer thereof,
Subsequently, the product is obtained by heating under reduced pressure to polymerize until a predetermined polymerization degree is reached.

The polymerization catalyst used in the polymerization of the polyester composition of the present invention needs to use a titanium compound from the viewpoint of high polymerization catalyst activity and the hue of the obtained polyester. The titanium compound is not particularly limited, and any titanium compound having a polymerization catalytic ability can be used. For example, titanium tetrabutoxide, titanium tetrapropoxide, titanium tetraethoxide, titanium isopropoxyoctylene glycol, titanium butoxyoctylene glycol, and further include a reaction mixture with these anhydrides, among which polymerization activity, From the viewpoint of cost, titanium tetrabutoxide or a reaction product thereof with an anhydride is particularly preferable. The amount of the titanium compound added is preferably such that the amount of the residual titanium compound in the produced resin composition is from 15 to 300 ppm in terms of titanium atoms, and particularly preferably from 20 to 100 ppm. If the amount of residual titanium in the resin composition is less than 15 ppm, sufficient polymerization activity cannot be obtained, which is not preferable for producing a polyester. On the other hand, if the amount of residual titanium in the resin composition exceeds 300 ppm, not only the color of the obtained resin composition becomes yellowish, but also the heat resistance of the obtained polyester decreases, which is not preferable.

In producing the polyester composition of the present invention, other additives such as a tinting agent, an antioxidant, an ultraviolet absorber, an antistatic agent and a flame retardant may be used, if necessary.
After completion of the melt polycondensation, the mixture is melt-extruded, cooled in a suitable cooling medium such as water, cut into a suitable size, and formed into chips. The tip may be a rectangular parallelepiped, a cylinder, a die, or a sphere. Further, if necessary, solid-state polymerization can be performed to obtain a predetermined intrinsic viscosity.

Although the intrinsic viscosity of the polyester composition is not particularly limited, it is generally in the range of 0.4 to 1.5 from the viewpoint of moldability and processed product strength.

In the polyester of the present invention, the L value and the b value measured by the Lab method must satisfy the following conditions.
In the following formula, the value of Lb is preferably 65 or more, more preferably 70 or more. The b value is preferably 8 or less, more preferably 6 or less. The larger the value of L, the better the whiteness, and the larger the value of b, the more yellowish the color becomes. When the resin composition does not satisfy the following formula conditions, it is further colored yellow by the heat history at the time of melt extrusion molding into a film or the like. It is not preferable because the willingness to purchase is reduced. Means for controlling the hue of the polyester resin composition so as to satisfy the following formula is not particularly limited. For example, the amount of Ti metal derived from the Ti compound catalyst remaining in the polyester composition is 15 to 30.
It can be achieved by adjusting the polymerization temperature and polymerization time appropriately to 0 ppm. 65 ≦ L−b (1) b ≦ 10 (2)

Further, the biaxially stretched film produced by using the polyester composition is a uniaxially stretched film obtained by heating and stretching the unstretched film obtained by melting the resin composition and cooling it on a drum in the longitudinal direction. Then, it can be obtained by heating, stretching in the lateral direction, heat setting and / or heat relaxation. The thickness of such a biaxially stretched film is 1
It is preferably from 300 to 300 µm, particularly preferably from 1 to 150 µm. Thickness 1
If it is less than μm, the thickness is too small to stabilize the film forming process, and in extreme cases, the film is cut. If the thickness exceeds 300 μm, the quality becomes excessive and uneconomical. Although the stretching ratio varies depending on the application, it is preferable that both the longitudinal stretching and the transverse stretching ratio be in the range of 2 to 6 times. When the stretching ratio is 2 times or less, the orientation of the film is insufficient and mechanical strength is not provided. On the other hand, when the stretching ratio exceeds 6 times, the stretching ratio is too high, so that film formation becomes difficult and the quality becomes excessive.

The biaxially stretched film using the polyester resin composition of the present invention may be provided with lubricity as required. The means for imparting lubricity is not particularly limited, but for example, SiO ₂ , BaSO ₄ , C
Examples thereof include a method of dispersing a lubricant such as aCO ₃ , alumina, alumina silicate, and crosslinked organic particles in a resin composition, and a method of providing a layer having lubricity on the surface of a film.

[0017]

The present invention will be described below in more detail with reference to examples. In addition, each characteristic value in an example was measured by the following method. In the examples, “parts” means “parts by weight”.

(1) Intrinsic viscosity Measured at 35 ° C. in a phenol / tetrachloroethane (weight ratio: 6: 4) mixed solvent.

(2) Measurement of metal content X-ray fluorescence (Rigaku Electric Industry Co., Ltd. X-ray fluorescence type 3270)
The amount of metal in the polymer (unit pp)
m) was measured. (3) Hue The polymer was heat-treated in a dryer at 160 ° C. for 60 minutes and dried.
Measure at 01 DP. (4) Measurement of foreign matter size 1 g of the chip was thoroughly washed with acetone and then with chloroform, and dissolved in a solution of hexafluoroisopropanol (hereinafter referred to as HFIP) / chloroform = 1/1. Filtration was performed with a membrane filter, and the collected material was observed with an optical microscope (× 200), and the number of foreign substances having a major axis of 10 μm or more was counted.

(5) Evaluation of surface defects of the biaxially stretched film 1 g of the obtained biaxially stretched film was observed with a deflection microscope.
Those having a major axis of a surface defect exceeding 50 μm were evaluated according to the following criteria. ◎: No number of foreign substances whose major axis exceeds 50 μm per 1 g of biaxially stretched film ○: Number of foreign substances whose major axis exceeds 50 μm per 1 g of biaxially oriented film 1 to 5 △: Per 1 g of biaxially oriented film 6 to 10 foreign substances whose major axis exceeds 50 μm ×: 10 or more foreign substances whose major axis exceeds 50 μm per 1 g of biaxially stretched film

Examples 1-3, Comparative Examples 1 and 2 100 parts of dimethyl naphthalene-2,6-dicarboxylate, 1,3-
Transesterification was carried out according to a conventional method using titanium tetrabutoxide as a catalyst so that 46.7 parts of propanediol and the amount of titanium in the obtained polyester became the amount shown in Table 1. Subsequently, a polycondensation reaction was carried out at a polymerization temperature shown in Table 1 under a high temperature and a high vacuum in a conventional manner to obtain poly- (1,
(3-Propylene) -2,6-naphthalate was obtained. The quality of this polymer was as shown in Table 1.

After drying the polyester pellet at 160 ° C. for 4 hours, it was supplied to an extruder popper and melted at a melting temperature of 25 ° C.
Melted at 0 ° C, surface temperature of 40 ° C through slit die
To obtain an unstretched film.
The unstretched film thus obtained is preheated at 80 ° C., and further heated between low-speed and high-speed rolls by an IR heater.
The film was heated to 10 ° C. and stretched 3.0 times in the machine direction, then supplied to a stenter, and stretched 3.3 times in the transverse direction at 110 ° C. The obtained biaxially oriented film was heat-set at a temperature of 145 ° C. for 5 seconds to obtain a 25 μm-thick polyester film. The evaluation results of the film surface defects were as shown in Table 1.

Comparative Examples 3 and 4 100 parts of dimethyl naphthalene-2,6-dicarboxylate and 46.7 parts of 1,3-propanediol were used, and 0.03 part of manganese acetate tetrahydrate was used as a transesterification catalyst. After transesterification according to a conventional method, trimethyl phosphate 0.023 was added.
Then, the transesterification reaction was substantially terminated.

Next, antimony trioxide was added as a polymerization catalyst so that the amount of antimony in the produced resin composition became the amount shown in Table 1, and was continuously added at a polymerization temperature shown in Table 1 at high temperature and high vacuum. Polycondensation reaction by the
(1,3-propylene) -2,6-naphthalate was obtained. The quality of this polymer was as shown in Table 1.

The obtained polymer was formed into a film in the same manner as in Example 1. The evaluation results of the film surface defects were as shown in Table 1.

[0026]

[Table 1]

[0027]

According to the present invention, a polyester film having less hue and surface defects can be provided. This polyester film can be used as a film for various packaging materials.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Masahiko Kosuge 77-family Kitayoshida-cho, Matsuyama-shi, Ehime Teijin Limited Matsuyama Works F-term (reference) 4F071 AA45 AB06 AC18A AE06A AF08 AF54 AF57 AH04 BA01 BB06 BB08 BC01 BC10 4J029 AA01 AB01 AC01 AC02 AD01 AD10 AE03 BA01 BA04 CC05A CC06A HA01 HB01 JF321

Claims (2)

[Claims] 1. A polyester composition polymerized by using 2,6-naphthalenedicarboxylic acid as a main dicarboxylic acid component, 1,3-propanediol as a main glycol component, and a Ti compound as a polymerization catalyst. The purity of the acid component is 99.5% or more, the residual amount of the Ti compound in the polyester composition is 15 to 300 ppm in terms of Ti atomic weight, and the L value and the b value measured by the Lab method are represented by the following formula ( A polyester composition satisfying (1) and (2). 65 ≦ L−b (1) b ≦ 10 (2) 2. A film obtained by subjecting the polyester composition according to claim 1 to melt biaxial stretching.