JPH0459823A - Ethylene glycol slurry for polyester addition - Google Patents

Abstract

PURPOSE:To obtain the title slurry having excellent dispersibility by comprising a specific amount of aluminum oxide particles containing a small amount of chlorine element. CONSTITUTION:The objective slurry comprising 5-40wt.%, preferably 10-30wt.% aluminum oxide particles containing 0.20-0.80wt.%, preferably 0.30-0.70wt.% chlorine element.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to an ethylene glycol slurry containing aluminum oxide particles that has excellent dispersibility when added to a polyester manufacturing process.

[Prior art and problems to be solved by the invention] Polyester films, especially biaxially oriented polyester films, have excellent physical and chemical properties and are used in various applications such as base films for magnetic recording media and capacitor dielectrics. used in In particular, films containing aluminum oxide particles have excellent wear resistance, so their range of application is expanding.

However, it has been difficult to stably obtain aluminum oxide particle-containing films having such excellent wear resistance properties.

That is, the particle-containing polyester can be obtained by adding a slurry containing aluminum oxide to the manufacturing process, but the dispersibility of the particles in the slurry is not always sufficient, and coarse agglomerated particles are often produced. This problem becomes more pronounced as the particle size of the particles in the slurry becomes smaller and as the concentration thereof becomes higher.

[Means to solve the problem]

The present inventors conducted intensive studies to improve this point, and found that among aluminum oxide particles, particles containing a specific amount of a specific element have extremely excellent dispersibility in ethylene glycol. This discovery led to the completion of the present invention.

That is, the gist of the present invention is that the chlorine element is 0.20 to 0.8
The present invention relates to an ethylene glycol slurry for adding polyester containing 5 to 40% by weight of aluminum oxide particles containing 0% by weight.

The present invention will be explained in more detail below.

The polyester referred to in the present invention refers to terephthalic acid, 2.6
- It refers to a polyester obtained using an aromatic dicarboxylic acid such as naphthalene dicarboxylic acid or its ester and ethylene glycol as the main starting materials, but it may contain other third components. In this case, the dicarboxylic acid component includes, for example, isophthalic acid, terephthalic acid,
One or more of 2,6 naphthalene dicarboxylic acid, adipic acid, sebacic acid, etc. can be used. As the glycol component, one or more of diethylene glycol, propylene glycol, butanediol, 1,4-cyclohexanedimetatool, neopentyl glycol, etc. can be used.

In any case, the polyester of the present invention refers to a polyester in which 80% or more of repeating structural units have ethylene terephthalate units or ethylene-2,6-naphthalene units.

Such polyester is usually used as a biaxially stretched film, but in order to improve its abrasion resistance, aluminum oxide particles with a primary particle size of 5 to 40 nm are present. Such fine aluminum oxide particles agglomerate to varying degrees during the production stage, so if necessary, they are subjected to dry crushing and classification treatment, followed by crushing and classification to form an ethylene glycol slurry.

As the crushing means, for example, a rod mill, a ball mill, a vibrating rod mill, a vibrating ball mill, a pan mill, a roller mill, an impact mill, an agitation grinding mill, a fluid energy mill, etc. are used.

According to the findings of the present inventors, elemental chlorine is contained in trace amounts, that is, 0.20 to 0.80% by weight, preferably 0.20 to 0.80% by weight.
The aluminum oxide particles containing 30 to 0.70% by weight have excellent dispersibility in ethylene glycol, and a highly concentrated slurry can be stably obtained.

When the chlorine content is less than 0.20% by weight, the effect of improving particle dispersibility is insufficient;
Even if it exceeds this amount, not only will the dispersibility not be further improved, but also corrosion of the equipment will proceed, which is not preferable.

In order to obtain aluminum oxide containing such an amount of elemental chlorine, it is convenient to adopt a method in which, for example, the heating conditions, production rate, etc. are adjusted in a flame hydrolysis method using anhydrous aluminum chloride as a starting material. Alternatively, a method such as reheating the obtained particles to reduce the amount of chlorine element may be adopted.

The reason why such aluminum oxide particles containing chlorine element have excellent dispersibility in slurry is not clear, but it is because the electronegativity of this element is particularly strong, so that stable cations exist on the particle surface. It is estimated to be. This seems to correspond to the high zeta potential of the particles of +20 to +50 mV.

In the present invention, the form in which the chlorine element exists is not necessarily clear, and it is thought that it probably exists in a state combined with aluminum or other metal elements, or in a state in which it is adsorbed as hydrogen chloride or chlorine gas. In any case, the effects of the present invention are specifically exhibited in the case of aluminum oxide particles containing a specific amount of nuclear elements.

The effects of the present invention are brought about by preventing the aggregation of small particles that are newly generated when secondary agglomerated particles are crushed during the crushing process, but it is not always necessary to completely disperse them into primary particles. There isn't.

Note that the aluminum oxide particles used in the present invention include:
In consideration of the abrasion resistance of the final film and damage to the base material that comes into contact with the film, aluminum oxide containing delta type or gamma type, particularly delta type in an amount of 70% by weight or more, is preferably used. In this case, a portion of the aluminum oxide, for example less than 10% by weight, is composed of St, Ti, Fe.
, Na, etc. may be substituted.

In the present invention, the aluminum oxide particles are dispersed, crushed, pulverized,
Perform processing such as classification and filtration. The particle concentration in the slurry is 5
If it is less than % by weight, the amount of ethylene glycol used increases,
The basic unit of ethylene glycol is too thick (too much, which is undesirable.Also, in the case of a slurry with a particle concentration exceeding 40% by weight, a tendency to agglomerate is observed in the slurry, and the dispersibility in the polymer also deteriorates. In addition, the ethylene glycol slurry referred to in the present invention contains water, methanol, diethylene glycol, etc. in an amount of about 20% by weight or less, and small amounts of phosphorus compounds, silica, carbon dioxide, calcium carbonate, etc., within a range that does not impair the gist of the present invention. It may also contain fine particles such as.

The slurry is added to the polyester synthesis reaction step, but it is particularly preferable to add it after the end of the transesterification reaction or esterification reaction and before the start of the polycondensation reaction from the viewpoint of operation and dispersibility.

〔Example〕

Hereinafter, the present invention will be explained in more detail with reference to Examples. In addition, "parts" in Examples and Comparative Examples indicate "parts by weight." Furthermore, the measurement method used in the present invention is as follows.

(1) Measurement of -order particle size The particle size was measured using an electron microscope, and the particle size (diameter) at a point where the volume fraction was only 50% in equivalent sphere terms was defined as the -order particle size.

(2) Content sample of chlorine element in aluminum oxide
The sample was heated to 000''C to gasify and collect the chlorine element in the sample, which was quantified by coulometric titration.

(3) Dispersion stability of particles in slurry Evaluation was made according to the following two methods.

Measurement of average particle size: Using a centrifugal sink type particle size distribution analyzer (Shimadzu Corporation 5A-CP3), the volumetric particle size distribution of the particles was determined by a sedimentation method based on Stotkus' drag law, and the average particle size was calculated.

Filtration: Wire mesh type filter (mesh #3600
), the ethylene glycol slurry was suction-filtered under certain conditions shown below, and the filtration rate was evaluated from the filtration rate or the degree of filter clogging.

(4) Dispersibility of particles in polymer was evaluated using two methods. First, the state of dispersion of particles in the polymer was evaluated by observing its cross section using an electron microscope. That is, a 10 μm 2 cross section of the chip was observed, and the maximum diameter of particles existing within that range was measured at 10 locations, and the third largest particle diameter was determined.

Note that the measurement conditions are as follows.

Furthermore, polyester containing aluminum oxide particles was made into a film, and the dispersibility of the particles was evaluated by measuring the maximum height of protrusions on the film surface.

The method for measuring the maximum height of the protrusion is as follows.

(5) Corrosion of the device was evaluated by the amount of decrease in test pieces. That is, a test piece of 5O3304 was held in a second stage polymerization apparatus for polyester, and the amount of decrease was measured after 100 batches of polyester containing 1% by weight of aluminum oxide particles were continuously polymerized by a batch method.

Example 1 10 parts of aluminum oxide, which is an aggregate of primary particles containing 0.51% by weight of elemental chlorine and having an average particle size of 0.02 μm, produced by flame hydrolysis, was dispersed in 90 parts of ethylene glycol.

Next, the mixture was stirred at 10.00 rpm for 30 minutes using a homomixer (T, Nihomo mixer manufactured by Tokushu Kika Kogyo ■), and then an ultrasonic disperser (US-300, 20kHz manufactured by Nippon Seiki ■).
When a dispersion treatment was carried out for 10 minutes using a solution, the apparent average particle size was 0.50 μm.

Next, a sand grinder (manufactured by Igarashi Kikai ■) was manufactured under the following conditions: media; glass beads with a diameter of 2 mm; amount of media; 1.
The slurry was 6 times the weight, the rotation speed was 200 rpm, and the crushing time was 40 minutes. After the crushing treatment, the average particle diameter of the obtained particles was sufficiently small as 0.05 μm, and the slurry containing the particles had good permeability.

The resulting slurry was then added to the polyester polymerization process. That is, 10 parts of the slurry was added to 130 parts of a transesterification reaction product mainly consisting of bis(β-hydroxyethyl) terephthalate obtained using magnesium acetate tetrahydrate as a transesterification catalyst, and then ethyl was added as a stabilizer. Acid phosphate and antimony trioxide were added as a polymerization catalyst to obtain polyethylene terephthalate by a conventional method.

The intrinsic viscosity of the polymer containing 1% by weight of aluminum oxide particles obtained after 4 hours was 0.65, the particles therein were almost uniformly dispersed, and the large particle size was 0.15 μm.
Met.

Next, a biaxially stretched film was produced using the polyester. That is, after melt-extruding polyester at 290°C to form an amorphous sheet,
The film was stretched 3.5 times in the transverse direction at 105°C and heat treated at 220°C to obtain a film with a thickness of 15 am. The maximum height of the obtained film was measured to be 0.013 μm, and it had a uniform and fine surface structure.

Example 2 Using aluminum oxide particles with a chlorine content of 0.65% by weight, the concentration of ethylene glycol slurry was 20%.
A slurry was obtained in the same manner as in Example 1, except that the characteristics thereof were evaluated. The particles in the slurry showed excellent dispersibility, and the state of dispersion in the polymer was also good.

Comparative Examples 1 and 2 Ethylene glycol slurries were obtained in the same manner as in Example 1, except that aluminum oxide particles having different chlorine contents were used as shown in Table 1, and their properties were evaluated. In the case of Comparative Example 1, in which the chlorine content is low, the particle dispersibility in the slurry and polymer is insufficient, while in the case of Comparative Example 2, in which this amount exceeds the amount specified in the present invention, corrosion of the equipment was observed and the equipment was not used. It was difficult.

Comparative Example 3 A slurry was obtained in the same manner as in Example 1 except that the slurry concentration was changed to 45%, and its characteristics were evaluated.

The resulting slurry showed a tendency to agglomerate, and the dispersibility of particles in the polymer obtained by adding the slurry was also insufficient.

The results obtained above are summarized in Table 1 below.

〔Effect of the invention〕

Aluminum oxide particles containing a specific amount of a specific element exhibit excellent dispersibility in ethylene glycol, and also have excellent dispersibility when added to and blended with polyester, so their industrial value is high.

Claims (1)

[Claims] (1) Ethylene glycol slurry for addition to polyester, containing 5 to 40% by weight of aluminum oxide particles containing 0.20 to 0.80% by weight of elemental chlorine.