JP3244233B2 - Thermoplastic polyester composition and film - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

FIELD OF THE INVENTION The present invention relates to thermoplastic polyester compositions and films. More specifically, it contains aluminum oxide with a specific crystal structure and specific surface area, and is used to manufacture magnetic tape when it is made into a film.
The present invention relates to a thermoplastic polyester composition having excellent wear resistance .

[0002]

2. Description of the Related Art In general, thermoplastic polyesters such as polyethylene terephthalate have excellent mechanical properties and are widely used as molded articles such as films and fibers. Usually, the polyester is made to contain inert particles for the purpose of imparting lubricity to the molded article, and to impart irregularities to the surface of the molded article. Although there are various types of such inert particles, generally, the inert particles have a problem that they lack affinity for the polyester and are inferior in abrasion resistance.

In order to solve this problem, studies have been made on surface treatments.
No. 58, JP-A-63-280763 (the surface of colloidal silica particles is modified with a glycol group) and JP-A-63-321345 (the surface of colloidal silica particles is modified with a coupling agent). 62-235
No. 353 (surface treatment of calcium carbonate particles with a phosphorus compound) has been proposed.

[0004] However, even when using such a known method, when friction is repeatedly used like a magnetic tape, particles also fall off. For this reason, the use of special particles has recently been proposed. Among them, it is disclosed in Japanese Patent Application Laid-Open Nos. 2-129230 (delta-type aluminum oxide particles) and No. 38444 (aluminum oxide particles).

[0005] However, according to the knowledge proposed in these, the dispersibility of the aluminum oxide particles is insufficient,
As a result, the wear resistance of molded products such as films and fibers
But it is still insufficient.

[0006]

[0007]

[0008]

[0009]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method in which repetitive friction is imposed as in the above-described magnetic tape.
An object of the present invention is to obtain a thermoplastic polyester film having excellent abrasion resistance even under a severe environment .

[0010]

The purpose of the means for solving the problems] The present invention described above, the aromatic dicarboxylic acid as a main acid component, having a thermoplastic polyester and θ-type crystal structure that an aliphatic glycol as a main glycol component, and B . E. FIG. T. To the law
The specific surface area due can be achieved by a thermoplastic polyester compositions and film characterized by containing the aluminum oxide particles is 50 to 200 m ² / g.

Various methods of synthesizing the θ-type aluminum oxide particles in the present invention are known, for example, a method of calcining a carbonate neutralized alum, a method of producing hydroxide obtained by spark discharge of metallic aluminum in water. Examples of the method include a method of firing and a method of firing a hydroxide obtained by hydrolyzing an aluminum alkoxide.

Incidentally, the crystal structure of the θ-type aluminum oxide obtained by the above-mentioned method or the like can be identified by X-ray diffraction analysis.

In addition, the B.I. E. FIG. T. Specific surface by the method
The product is preferably 10 m ² / g or more, more preferably 50 m ² / g.
The above is preferred. Further, it is preferably 600 m ² / g or less.
No. Particularly preferred is 50 to ²⁰⁰ m ² / g .

However, such fine particles are very easy to agglomerate and generally form secondary particles agglomerated in the slurry and the polymer. When such agglomeration proceeds, coarse particles are formed depending on the degree, and when used for a film or a fiber, such a portion is unfavorably disadvantageously cut off and dropped off during contact running.

As a method for obtaining the composition of the present invention, there is a method in which a slurry obtained by subjecting θ-type aluminum oxide particles to wet dispersion treatment in the presence of a solvent is added to a polyester polymerization reaction or the like to complete the reaction.

In the slurry obtained by the wet dispersion treatment, the particles are aggregated to form secondary particles, but the secondary particle diameter is very fine, there is no coarse aggregate, and the particles are well dispersed. State. In addition, the secondary particle diameter here is,
This is the average diameter equivalent to a circle when 1,000 particles are observed with a transmission electron microscope.

When wet dispersion treatment is carried out in the presence of a solvent, the viscosity increases, so that the concentration of the aluminum oxide particles is preferably 1 to 50 wt%, more preferably 3 to 30 wt%.
wt% is preferred.

The solvent used at this time is not particularly limited.
In consideration of the subsequent addition to the polyester, a glycol component such as a main component of the polyester and a copolymer component is preferred. Specifically, ethylene glycol, tetramethylene glycol, hexamethylene glycol, diethylene glycol, propylene glycol, butanediol, neopentyl glycol, polyoxyalkylene glycol, p-xylylene glycol, 1,4-cyclohexanedimethanol, 5-sodium Sulforesorcin and the like. In this case, the distributed processing includes
Examples include ordinary stirring treatment, ultrasonic treatment, and medium-type dispersion treatment, and among others, medium-type dispersion treatment represented by a sand grinder and the like is preferable.

As described above, when the θ-type aluminum oxide is wet-dispersed in the presence of a solvent, the dispersibility is extremely improved, and the secondary particle size thereof can be arbitrarily determined according to the purpose of the molded article from the thermoplastic polyester composition. You can also choose. When used for a film or a fiber, if it is too large, coarse projections are formed on a molded product.
m or less, and more preferably 3.0 μm or less. Further, the thickness is preferably 0.01 μm or more. Particularly preferred is 0.01 to 1 μm.

The amount of addition is determined for the same reason. In other words, when used for films or fibers, if too much addition is made, coarse projections will occur on the molded product,
The total amount of the aluminum oxide particles is preferably 0.01 to 30 parts by weight, more preferably 0.05 to 20 parts by weight, based on 100 parts by weight of the thermoplastic polyester. Particularly preferred is 0.05 to 10 parts by weight.

In the present invention, the aromatic dicarboxylic acid is
Specifically, terephthalic acid, isophthalic acid, naphthalene-
Examples thereof include 2,6-dicarboxylic acid and 5-sodium sulfoisophthalic acid. On the other hand, the aliphatic glycol in the present invention specifically includes ethylene glycol, diethylene glycol, propylene glycol, butanediol, tetramethylene glycol, hexamethylene Glycol, neopentyl glycol, polyoxyalkylene glycol and the like.

Specific examples of the thermoplastic polyester comprising an aromatic dicarboxylic acid and an aliphatic glycol include polyethylene terephthalate, polybutylene terephthalate, and polyethylene-2,6-naphthalate. The polyester may be a homopolyester or a copolyester containing a copolymer component in a small amount.Examples of the copolymer component at this time include:
Dicarboxylic acid components such as adipic acid, sebacic acid, phthalic acid, isophthalic acid, naphthalene-2,6-dicarboxylic acid and 5-sodium sulfoisophthalic acid; polycarboxylic acid components such as trimellitic acid and pyromellitic acid; Examples of the diol component include methylene glycol, hexamethylene glycol, diethylene glycol, propylene glycol, neopentyl glycol, polyoxyalkylene glycol, p-xylylene glycol, 1,4-cyclohexanedimethanol, and 5-sodium sulforesorcin.

As the degree of polymerization of such a thermoplastic polyester, [η] is preferably 0.30 or more as an intrinsic viscosity measured by dissolving it in o-chlorophenol. The carboxyl terminal group in the thermoplastic polyester is preferably 20 eq / t to 100 eq / t.

In order to improve the antioxidant and the running property at the time of film formation and processing, the winding property, etc., if necessary, known particles are added as long as the effects of the present invention are not impaired. Is also good. Examples of particles for improving handling properties such as running properties and winding properties include calcium carbonate, kaolin, talc, magnesium carbonate, barium carbonate, calcium carbonate, barium sulfate, lithium phosphate, calcium phosphate, magnesium phosphate, and silicon oxide. , One or more metal compounds selected from terephthalates such as titanium oxide, lithium fluoride, calcium oxalate, Ca, Ba, Zn, Mn, and divinylbenzene, styrene, acrylic acid and methacrylic acid or alkyl esters thereof And the like, and particles of a crosslinkable polymer obtained from homopolymerization or copolymerization of a vinyl monomer such as phenol, and particles of phenol and urea.

The addition of the slurry obtained by wet-dispersing the θ-type aluminum oxide particles in the presence of a solvent to the thermoplastic polyester polymerization reaction system may be carried out at any time until the completion of the polymerization reaction. However, the time is preferably from before the transesterification reaction to the start of the polycondensation reaction under reduced pressure.

By forming the thermoplastic composition thus obtained into a film by a known method, the film intended for the present invention can be obtained. At this time, all the layers may be films composed of the composition of the present invention , or at least one surface may be a composite film of two or more layers composed of the composition of the present invention.

[0027]

Next, the present invention will be specifically described with reference to Examples and Comparative Examples.

(1) Evaluation of specific surface area of aluminum oxide particles E. FIG. T. It was measured according to the method (m ² / g).

(2) Evaluation of Secondary Particle Diameter of Aluminum Oxide Particles Aluminum oxide particles are blended in polyester,
After cutting into an ultra-thin section having a thickness of 0.2 μm, the section was observed with a transmission electron microscope, and evaluated by an area average diameter (μm) of 1000 secondary particles in an aggregated state.

(3) Evaluation of abrasion resistance The obtained polyester composition was formed into a biaxially stretched film by the method described in Examples, and a tape-shaped roll slit into a narrow width was fixed to a guide roll made of stainless steel SUS-304 at a constant tension. in high-speed, rubbing long, given rank as follows by white powder amount generated in the guide roll surfaces, primary and
Grade 2 was accepted. 1st class: no white powder generated 2nd class: slightly generated white powder 3rd class: fairly white powder generated

(4) Evaluation of Surface Irregularity The obtained polyester composition was formed into a biaxially stretched film by a usual method, using a Surfcom surface roughness meter according to JIS B-0601, a needle diameter of 2 μm, a load of 70 mg, and a measurement reference length. The center line average roughness (Ra) was measured under the conditions of 0.25 mm and cutoff 0.08 mm.

[0032]

Example 1 B. E. FIG. T. 10 parts by weight of the θ-type aluminum oxide particles having a specific surface area of 146 m ² / g and 90 parts by weight of ethylene glycol were mixed, and the mixture was dispersed using a sand grinder.
100 parts by weight of the aluminum oxide particles / ethylene glycol slurry (A) were obtained.

On the other hand, a transesterification reaction was conducted by adding 0.05 parts by weight of magnesium acetate as a catalyst to 100 parts by weight of dimethyl terephthalate and 64 parts by weight of ethylene glycol , and then the slurry (A) prepared above was added to the reaction product.
2.5 parts by weight, 0.03 part by weight of antimony oxide as a catalyst, and 0.03 part by weight of trimethyl phosphate as a heat stabilizer
The polycondensation reaction was performed by adding a weight part, and the limiting viscosity was 0.61.
Thus, a polyethylene terephthalate composition of No. 9 was obtained. The secondary particle diameter measured by a transmission electron microscope was 0.22 μm.

The polyethylene terephthalate composition was melt-extruded at 290 ° C., stretched at 90 ° C. three times vertically and horizontally, and then heat-treated at 220 ° C. for 15 seconds to obtain a biaxially stretched polyethylene terephthalate film having a thickness of 15 μm. .

When this film was evaluated, Ra =
0.011Myuemu, comprehensive evaluation in abrasion resistance evaluation 2 grade was very good.

Example 2 10 parts by weight of calcite-type calcium carbonate particles having an average particle diameter of 0.63 μm and 90 parts by weight of ethylene glycol were mixed and dispersed using a sand grinder.
Filtration was performed with a filter having an absolute filtration accuracy of 5 μm to obtain 100 parts by weight of calcite-type calcium carbonate particles / ethylene glycol slurry (B).

In Example 1, B.I.
E. FIG. T. The specific surface area was changed from 146 m ² / g to 85 m ² / g, and the slurry (B) 2 obtained above
A biaxially stretched film was obtained in the same manner except that parts by weight were added simultaneously with the θ-type aluminum oxide / ethylene glycol slurry.

When this film was evaluated, Ra =
0.017 micrometer, comprehensive evaluation in abrasion resistance evaluation 2 grade was very good.

Example 3 Coextruded using polyethylene terephthalate having an intrinsic viscosity of 0.622 containing no particles and the polymer of Example 1,
A 14 μm-thick biaxially oriented laminated film in which the polymer of Example 1 having a thickness of 1 μm was laminated on both sides of polyethylene terephthalate containing no particles was obtained.

When this film was evaluated, Ra =
0.010, comprehensive evaluation in abrasion resistance evaluation 2 grade was very good.

Example 4 The procedure of Example 3 was repeated, except that the polymer of Example 2 was laminated on both sides of the particle-free polyethylene terephthalate in place of the polymer of Example 1 to a thickness of 14 μm.
m was obtained.

The result of the evaluation of this film, comprehensive evaluation in abrasion resistance evaluation level 2 was excellent.

Example 5 A slurry of 10 parts by weight of spherical organic particles having an average particle diameter of 0.45 μm (divinylbenzene / vinylbenzene = 80/20 copolymer) / 90 parts by weight of water was used in a twin-screw kneader equipped with a vent. At the time of melt-kneading polyethylene terephthalate, and finally the content of the above-mentioned spherical organic particles is 1% by weight.
A polyethylene terephthalate composition was obtained.

Next, in Example 1, θ-type aluminum oxide was added to B.I. E. FIG. T. 80 parts by weight of the polyethylene terephthalate composition obtained in exactly the same manner except that the specific surface area was changed from 146 m ² / g to 85 m ² / g, and 20 parts by weight of the polyethylene terephthalate composition containing 1% by weight of the organic particles. Was melt mixed. Next, the obtained molten mixture was melt-formed into a film in the same manner as in Example 1 to a thickness of 14 μm.
m was obtained.

As a result of evaluating this film, Ra = 0.
019Myuemu, comprehensive evaluation in abrasion resistance evaluation 2 grade was very good.

Example 6 The procedure of Example 3 was repeated except that the polymer of Example 1 was replaced with a melt mixture of the two polyethylene terephthalate compositions of Example 5 on both sides of the particle-free polyethylene terephthalate. Thus, a film having a thickness of 14 μm was obtained.

As a result of evaluating this film, Ra = 0.
018Myuemu, comprehensive evaluation in abrasion resistance evaluation 2 grade was very good.

Comparative Example 1 B. E. FIG. T. A mixture of 10 parts by weight of δ-type aluminum oxide particles having a specific surface area of 108 m ² / g and 90 parts by weight of ethylene glycol is subjected to a dispersion treatment using a sand grinder,
100 parts by weight of aluminum oxide particles / ethylene glycol slurry (C) were obtained.

On the other hand, after transesterification was conducted by adding 0.05 parts by weight of magnesium acetate as a catalyst to 100 parts by weight of dimethyl terephthalate and 64 parts by weight of ethylene glycol, 5 parts by weight of the slurry (C) previously prepared was added to the reaction product. And 0.03 parts by weight of antimony oxide as a catalyst and 0.03 parts by weight of trimethyl phosphate as a heat stabilizer were added to carry out a polycondensation reaction to obtain a polyethylene terephthalate composition having an intrinsic viscosity of 0.619. The secondary particle diameter measured by a transmission electron microscope was 0.18 μm. This polyethylene terephthalate composition was melt-extruded at 290 ° C., stretched at 90 ° C. three times each in the length and width directions, and then heat-treated at 220 ° C. for 15 seconds to obtain a biaxially stretched polyethylene terephthalate film having a thickness of 15 μm.

When this film was evaluated, Ra =
0.011Myuemu, were abrasion resistance evaluation grade 2 but comprehensive evaluation was bad.

Comparative Example 2 The same procedure as in Comparative Example 1 was repeated except that
A biaxially stretched film was obtained in the same manner except that the gamma-type aluminum oxide was changed to 8 m ² / g. Results of evaluation of the films was the wear resistance evaluation grade 2 but comprehensive evaluation was bad.

A molded article such as a film or a fiber obtained from the thermoplastic polyester composition of the present invention exhibits excellent durability in applications subject to strong shearing force, and particularly has excellent abrasion resistance during the production of a magnetic tape. Therefore, it can be preferably used as a support for a magnetic tape.

Continuation of the front page (56) References JP-A-2-185533 (JP, A)

Claims (2)

(57) [Claims] 1. A thermoplastic polyester having an aromatic dicarboxylic acid as a main acid component and an aliphatic glycol as a main glycol component, a thermoplastic polyester having a θ-type crystal structure, and B.I.
E. FIG. T. A thermoplastic polyester composition containing aluminum oxide particles having a specific surface area of 50 to 200 m ² / g by a method. 2. A film comprising the thermoplastic polyester composition according to claim 1.