JP3136718B2 - Polyester composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyester composition, and more particularly to a polyester composition containing a divinylbenzene / ethylvinylbenzene copolymer and zirconium oxide particles.

[0002]

2. Description of the Related Art Thermoplastic polyesters such as polyethylene terephthalate have excellent mechanical and chemical properties and are widely used as molded articles such as films and fibers.

[0003] However, there is a problem that productivity is reduced due to insufficient slipperiness when processing polyester into a molded article. As a method for solving such a problem, a method of dispersing inert particles in polyester to impart irregularities to the surface of a molded product has been conventionally performed (for example, Japanese Patent Application Laid-Open No. Sho 52-86471, Kaisho 59-17
No. 1623). These methods are effective in solving the problem of slipperiness, but when they are molded products, they have abrasion resistance,
The scratch resistance cannot be set to a satisfactory level.

If the wear resistance of a molded product, for example, a film for magnetic tape, is low, abrasion powder of the film is likely to be generated during the manufacturing process of the magnetic tape, and coating loss occurs in the process of applying the magnetic layer. This causes dropout of magnetic recording. In addition, when using a magnetic tape, in many cases, the magnetic tape is run while being in contact with a recording / reproducing device, so that abrasion powder generated at the time of the contact adheres to the magnetic material, and the magnetic recording loses during recording / reproducing (drop / drop). Out).

If a molded product, for example, a film for magnetic tape has low scratch resistance, foreign matter is generated during the manufacturing process of the magnetic tape, and a scratch is easily formed on the film surface. Drop out) and scratches easily on the film surface when using magnetic tape at high speed.

That is, a film for a magnetic tape needs to have slipperiness, abrasion resistance and scratch resistance both during the manufacturing process and when used as a magnetic tape.

As a technique for improving abrasion resistance, there is a method of containing fine particles. For example, one or more kinds of inert inorganic particles such as calcium carbonate, titanium oxide, colloidal silica, etc. It has been conventionally performed to add a combination of small particles) or to add organic particles such as crosslinked polymer particles. However, in the current situation where the required level of film performance is increasing, the performance required for the film surface is more sophisticated in order to simultaneously satisfy the above contradictory characteristics, and at present, satisfactory results cannot be obtained. It is.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the above-mentioned drawbacks of the prior art. Particularly, when a film is formed, a polyester composition excellent in all of slipperiness, abrasion resistance and scratch resistance is provided. To get things.

[0009]

An object of the present invention is to provide a polyester comprising a difunctional acid component mainly composed of an aromatic dicarboxylic acid and at least one glycol component, and a polyester having an average particle size of 0.01 to 5 μm. Divinylbenzene / ethylvinylbenzene copolymer particles and an average particle size of 0.
This is achieved by a polyester composition comprising zirconium oxide particles of 005 to 3 μm.

[0010] The bifunctional acid component of the polyester of the present invention is mainly composed of an aromatic dicarboxylic acid or an ester-forming derivative thereof.
6-naphthalene dicarboxylic acid, 1,2-bis (2-chlorophenoxy) ethane-4,4'-dicarboxylic acid, dimethyl terephthalate as an ester-forming derivative thereof,
Examples thereof include dimethyl 2,6-naphthalenedicarboxylate and dimethyl 1,2-bis (2-chlorophenoxy) ethane-4,4-dicarboxylate, with terephthalic acid or dimethyl terephthalate being preferred.

The glycol component includes ethylene glycol, butylene glycol, diethylene glycol, propylene glycol, polyethylene glycol,
1,4-cyclohexanedimethanol and the like,
Of these, ethylene glycol is preferred.

These dicarboxylic acids or their ester-forming derivatives and glycol components can be used alone or in combination of two or more. Further, other components may be used as copolymer components.

When terephthalic acid or its ester-forming derivative is used as the difunctional acid component and ethylene glycol is used as the glycol component, specific examples of the copolymerization component include diethylene glycol, propylene glycol, neopentyl glycol, and polyalkylene. Glycol, p-xylylene glycol, 1,4-cyclohexanedimethanol, diol components such as 5-sodium sulforesorcin, adipic acid, sebacic acid, phthalic acid, isophthalic acid, 2,6-naphthalene dicarboxylic acid,
Examples thereof include a dicarboxylic acid component such as 5-sodium sulfoisophthalic acid, a polyfunctional dicarboxylic acid component such as trimellitic acid and pyromellitic acid, and an oxydicarboxylic acid component such as p-oxyethoxybenzoic acid.

When the dicarboxylic acid component is a dicarboxylic acid, it is subjected to an esterification reaction with glycol, and when the dicarboxylic acid ester is a dicarboxylic acid ester, it is subjected to a transesterification reaction with glycol.
Polyester is obtained by polycondensation under reduced pressure. It is also possible to carry out polycondensation using the prepolymer itself as a starting material.

The composition ratio of the divinylbenzene / ethylvinylbenzene copolymer particles used in the present invention is not particularly limited, but the amount of divinylbenzene units in the particles exceeding 50% by weight in monomer conversion is particularly preferable. 54% by weight with good particle dispersibility during polyester polymerization or melt molding
Those described above are preferred. For example, 100% of commercially available divinylbenzene (containing ethylvinylbenzene and a small amount of diethylbenzene in addition to divinylbenzene) is polymerized,
In the form of particles, divinylbenzene is preferably at least 54% by weight as a pure content in the particles.

The divinylbenzene / ethylvinylbenzene copolymer particles of the present invention may contain other components, such as styrene, polystyrene, or diethylbenzene which is an impurity of commercially available divinylbenzene. And the like.

Further, the divinylbenzene / ethylvinylbenzene copolymer particles used in the present invention are preferably heat-resistant particles having a thermal decomposition temperature (a 10% weight loss temperature) of at least 390 ° C. by a thermobalance. Preferably the pyrolysis temperature is 40
The temperature is 0 ° C. or higher, more preferably 410 ° C. or higher. If the thermal decomposition temperature is lower than 390 ° C., the particles will agglomerate during the polymerization of the polyester or during melt molding, so that the slipperiness and abrasion resistance will deteriorate.

The divinylbenzene / ethylvinylbenzene copolymer particles used in the present invention preferably have a spherical particle shape and a uniform particle size distribution in terms of lubricity and abrasion resistance.

That is, the volume shape factor is 0.35 / π /
6 are preferred, and more preferably 0.45 or more. [However, the volume shape factor f is represented by the following equation. f = V / D ³ , where V is the particle volume (μm ³ ),
D is the maximum diameter (μm) of the particles on the projection surface] For example, in the method of pulverization by pulverization disclosed in Japanese Patent Application Laid-Open No. 55-158937, the particles have an irregular shape and a uniform particle size distribution. Is difficult to obtain, and coarse particles are present. Particularly when the film is formed, it is not preferable because clogging of the filter at the time of film formation and slipperiness and abrasion resistance as a product are impaired. As the divinylbenzene / ethylvinylbenzene copolymer particles of the present invention, those obtained by a known production method can be used. As a known production method, for example, there is a method by emulsion polymerization as described below. (1) A soap-free polymerization method, that is, a method in which an emulsifier is not used or polymerization is performed using an extremely small amount of an emulsifier. (2) A seed polymerization method in which polymer particles are added to a polymerization system prior to emulsion polymerization and emulsion polymerization is performed. (3) A core-shell polymerization method in which a part of the monomer component is emulsion-polymerized and the remaining monomer is polymerized in the polymerization system. (4) JP-A-54-97582 and JP-A-54-97582
No. 126288, a polymerization method using Eugelstatt or the like. (5) A polymerization method using no swelling aid in the method of (4).

In the present invention, in order to improve the affinity between the divinylbenzene / ethylvinylbenzene copolymer particles and the polyester, divinylbenzene / ethylvinylbenzene copolymer particles having an alkali metal salt of a carboxyl group as a functional group are used. Is preferred.

Examples of the alkali metal salt of a carboxyl group include a Na salt, a K salt, and a Li salt. Among them, a Na salt of a carboxyl group is preferable because the affinity is further improved.

The chemical species having a functional group for introducing an alkali metal salt of a carboxyl group may be a monomer or a polymer, and is not particularly limited. Of these, methacrylic acid, acrylic acid, or a polymer thereof is preferable.

Further, the chemical species having a carboxyl group may be a chemical species having no functional group or a chemical species having a functional group other than the carboxyl group.
In that case, a styrene-based material is preferred in terms of heat resistance.

The method for introducing the alkali metal salt of a carboxyl group is not particularly limited. However, from the viewpoint of the heat resistance of the particles, particles which are to be once highly crosslinked are produced, and the alkali particles of the carboxyl group are formed on the surface of the base particles. Preferably, a metal salt is introduced. For example, in a divinylbenzene-ethylvinylbenzene copolymer as a base particle, a particle highly crosslinked with divinylbenzene is produced, and then,
Carboxyl groups are introduced into the particle surface with methacrylic acid. Then, by setting the inside of the particle production system to the alkali side, a functional group of -COONa is introduced to the particle surface.

The amount of the monomer or polymer for introducing the alkali metal salt of the carboxyl group is preferably from 0.01 to 20% by weight, more preferably from 0.1 to 10% by weight, based on the base particles.

The average particle size of the divinylbenzene / ethylvinylbenzene copolymer particles used in the present invention is 0.01 to 5
μm, and more preferably 0.05-1.
0 μm. If the average particle size is less than 0.01 μm, when the film is formed, the slipperiness decreases. On the other hand, if the average particle size exceeds 5 μm, abrasion resistance and scratch resistance deteriorate due to generation of voids and coarse projections.

The addition amount of the particles is preferably 0.001 to 10 parts by weight, more preferably 0.005 to 5 parts by weight, based on 100 parts by weight of the thermoplastic polyester.

When divinylbenzene / ethylvinylbenzene copolymer particles having an average particle size of 0.01 to 5 μm are used, the first component has an average particle size of 0.01 μm or more and less than 0.1 μm, preferably 0.1 μm or less. 0.01 μm or more and 0.08
μm, more preferably 0.02 μm or more and 0.06
μm and a second component having an average particle size of 0.1 to
It is preferable to use divinylbenzene / ethylvinylbenzene copolymer particles of a two-component system having a particle size of 5 μm, preferably 0.1 to 2 μm, since the lubricity is improved.

Further, when divinylbenzene / ethylvinylbenzene copolymer particles composed of two components are dispersed and contained in polyester, the weight average diameter D _W and the number average diameter D _N
And the value of D _W / D _N is preferably 1.2 or more and 10 or less, more preferably 1.2 or more and 5 or less.

When divinylbenzene / ethylvinylbenzene copolymer particles composed of two components are dispersed and contained in polyester, particles obtained by separately producing two kinds of divinylbenzene / ethylvinylbenzene copolymer particles are used. It may be mixed and dispersed in the polyester,
From the viewpoints of workability, cost, and surface flatness, two steps are required during the production of divinylbenzene / ethylvinylbenzene copolymer particles.
It is preferable to produce particles of the same type at the same time and disperse them in the polyester.

As described above, two components of divinylbenzene.
When ethylvinylbenzene copolymer particles are used, the second
The amount of the divinylbenzene / ethylvinylbenzene copolymer particles added as a component is usually 0.0001 to 10% by weight, more preferably 0.001% by weight, based on the polyester.
To 15% by weight, more preferably 0.01 to 5% by weight. The amount of the divinylbenzene / ethylvinylbenzene copolymer particles as the first component is usually 0.001 to 5% by weight, based on the weight of the second component divinylbenzene / ethylvinylbenzene copolymer particles. Preferably it is 0.01 to 3% by weight, more preferably 0.05 to 2% by weight.

Further, the divinylbenzene / ethylvinylbenzene copolymer particles of the first component and the second component may both have an alkali metal salt of a carboxyl group as a functional group. The benzene / ethylvinylbenzene copolymer particles preferably have a carboxyl group alkali metal salt as a functional group. In order to improve the heat resistance or control the refractive index of the divinylbenzene / ethylvinylbenzene copolymer particles, the divinylbenzene / ethylvinylbenzene copolymer particles are coated with an inorganic substance such as SiO ₂ and TiO ₂ around the particles. Is also good. The zirconium oxide particles of the present invention can be obtained by, for example, a method in which impurities are scattered and removed from zircon sand or baddelite which are natural minerals by melting (dry method), a method in which impurities are removed by washing with water after alkali melting (wet method), or the like. .

The average particle diameter of the zirconium oxide used in the present invention is 0.005 to 3 μm, preferably 0.005 to 3 μm.
０．３0.3 μm. When the average particle size is smaller than 0.005 μm, the effects of abrasion resistance and scratch resistance aimed at by the present invention are not exhibited, and when the average particle size is larger than 3 μm, the film is frequently torn during the production of the film, or the film surface roughness is increased. And the electrical properties of the magnetic tape are reduced, which is not preferable.

The addition amount of the particles is preferably 0.01 to 10 parts by weight, more preferably 0.05 to 5 parts by weight, with respect to 100 parts by weight of the thermoplastic polyester.

The divinylbenzene / ethylvinylbenzene copolymer particles and zirconium oxide particles of the present invention are:
The polyester can be added and mixed by various known methods. It may be added to the polyester during the production stage.
The polymer may be added to and mixed with the polymer in a molten state using an extruder having a shaft, a twin-screw or the like, or an extruder having a vent mechanism. When it is added during the polyester production stage, it is particularly preferred from the viewpoint of particle dispersibility that it is added before the start of polyester polymerization and during the polymerization reaction.
The addition of the particles in the precursor stage or the polycondensation stage before the production of the polyester composition is preferably performed as a slurry of ethylene glycol.

The dispersion in a dispersion medium such as ethylene glycol may be performed by using, for example, a high-speed disperser, a sand mill, a roll mill, or the like.

The composition of the present invention may further contain lithium, sodium,
Metal compound catalysts of compounds such as calcium, magnesium, manganese, zinc, antimony, germanium, and titanium, phosphorus compounds as coloring inhibitors, inorganic and organic particles other than divinylbenzene / ethylvinylbenzene copolymer particles and zirconium oxide particles. Molecular fine particles and the like can be appropriately added as needed.

[0038]

The present invention will be described in detail below with reference to examples. In addition, each characteristic value measurement of the obtained polyester composition was performed according to the following method.

A. Particle characteristics (1) Particle size The average particle size was measured by an electron micrograph of the particles.
It was determined by the particle equivalent sphere diameter corresponding to the volume% point. The equivalent sphere diameter is the diameter of a sphere having the same volume as a particle.

Further, the weight average diameter (D _W ) and the number average diameter (D
_N ) is an image analyzer (for example, QTM-90)
0: manufactured by Cambridge Instrument) by numerical processing, and the ratios were obtained.

(2) Thermal Decomposition Temperature of Particles Rigaku Denki TAS-100 under a nitrogen atmosphere at a temperature rising rate of 2
A thermobalance weight loss curve at 0 ° C./min was measured. The 10% weight loss temperature was taken as the pyrolysis temperature.

B. Polymer properties (1) Intrinsic viscosity Measured in orthochlorophenol at 25 ° C.

C. Film characteristics (1) Surface roughness Ra (μm) According to JIS B-0601, using a surfcom surface roughness diameter, needle diameter 2 μm, load 70 mg, measurement standard length 0.25
mm, the center line average roughness measured under the condition of cutoff 0.08 mm was adopted.

(2) Slipperiness (μ _k ) A film was slit to 1/2 inch, and a tape running tester TBT-300 type [manufactured by Yokohama System Laboratory Co., Ltd.]
, And run in a 20 ° C., 60% RH atmosphere, and the initial μ _k was determined by the following equation. The guide diameter is 6mmφ
And the guide material is SUS27 (surface roughness 0.2
S), the winding angle is 180 °, and the running speed is 3.3 cm / sec. μ _k = 0.773 log (T ₁ / T ₂ ) T ₁ : Tension on the outgoing side T ₂ : Tension on the incoming side Those having the above μ _k of 0.35 or less have good slipperiness. Here, slipperiness when mu _k is that the larger the film during processing or product than 0.5 is extremely poor.

(3) Abrasion resistance Using a tape running tester TBT-300 (manufactured by Yokohama System Research Institute Co., Ltd.), the test was performed at 35 ° C. and 60 RH atmosphere.
After running repeatedly 0 times, white shavings (white powder) adhering to the guide portion are visually determined.

Here, the guide diameter is 80 mmφ, the guide material is SUS27 (surface roughness 0.2 S), the winding angle is 180 °, and the running speed is 3.3 cm / sec. The evaluation criteria are as follows. 1st grade: not adhered at all 2nd grade: slightly adhered 3rd grade: heavy adhesion 4th grade: adhered to the whole surface

(4) Scratch resistance A film obtained by slitting a film into a tape having a width of 1/2 inch is run on guide pins (surface roughness: 0.1 μm in Ra) using a tape running tester. (Running speed: 1,000 m / min, running frequency: 20 passes, winding angle: 60
°, running tension 65g). At this time, the scratches in the film were observed with a microscope. The number of scratches with a width of 2.5 μm or more per tape width was less than 2 grades; 10 or more were rated as 4th grade.

EXAMPLE 1 Zircon sand, a natural mineral, was alkali-melted and then impregnated.
The substance was removed to obtain zirconium oxide particles. Next, 10 parts by weight of zirconium oxide particles, ethylene glycol 9
0 parts by weight were mixed and stirred with a dissolver at room temperature for 1 hour to obtain a zirconium oxide particle / ethylene glycol slurry (A). The slurry is then granulated in a sand mill
The diameter was adjusted.

Next, 100 parts by weight of dimethyl terephthalate, 62 parts by weight of ethylene glycol, and 0.06 parts by weight of magnesium acetate were added to carry out a transesterification reaction, and 6 parts by weight of the slurry (A) prepared above was added. Divinylbenzene / ethylvinylbenzene copolymer particles having a thermal decomposition temperature of 405 ° C dispersed as an ethylene glycol slurry [commercially available divinylbenzene 100% (Aldo
Rich product number 16,909-9) (55% divinylbenzene, 40% ethylvinylbenzene, 5% diethylvinylbenzene) polymerized. 0.05 parts by weight and 0.
A polycondensation reaction was performed by adding 03 parts by weight of antimony oxide to obtain a polyethylene terephthalate composition having an intrinsic viscosity of 0.600. The average particle diameters of the zirconium oxide particles and the divinylbenzene / ethylene vinylbenzene copolymer particles in the polymer were 0.1 μm and 0.6 μm, respectively.

The polyethylene terephthalate composition obtained here was melt-extruded at 290 ° C. to obtain an unstretched film. Further, this was stretched three times in the vertical and horizontal directions at 90 ° C. and heat-treated at 220 ° C. for 10 seconds to obtain a film having a thickness of 15 μm. As a result of evaluating the film properties, it was found that the sliding property, abrasion resistance and scratch resistance were all good. (Table 1) Examples 2 to 7 The zirconium oxide particles and divinylbenzene / ethylvinylbenzene copolymer particles shown in Table 1 obtained in the same manner as in Example 1 were used with the average particle size and the amount added being changed. A polyester composition and a biaxially stretched film were obtained in the same manner as in Example 1.

Table 1 shows the evaluation results. It can be seen that the obtained film has good sliding properties, abrasion resistance and scratch resistance.

Comparative Examples 1 to 6 In the case where zirconium oxide particles or divinylbenzene / ethylvinylbenzene copolymer particles as shown in Table 2 were used alone, or when other particles were used, the polyester was produced in the same manner as in Example 1. A composition and a biaxially stretched film were obtained.

Table 2 shows the evaluation results. None of the obtained films could simultaneously satisfy the slipperiness, abrasion resistance and scratch resistance.

[0054]

[Table 1]

[Table 2]

[0055]

When the thermoplastic polyester composition of the present invention is formed into fibers, films or other molded products, it exhibits an effective effect on slip, abrasion resistance and scratch resistance. It is suitable for magnetic tapes.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) C08L 67/00-67/03

Claims (1)

(57) [Claims] 1. A polyester comprising a difunctional acid component mainly composed of an aromatic dicarboxylic acid and a glycol component, divinylbenzene / ethylvinylbenzene copolymer particles having an average particle size of 0.01 to 5 μm, and an average particle size. 0.005-
A polyester composition comprising 3 μm zirconium oxide particles.