JPS62207356A - Method of improving slipperiness - Google Patents

Abstract

PURPOSE:To obtain a polyester having excellent slipperiness and wear resistance, by adding fine spherical particles of a specified inorg. oxide to a polyester. CONSTITUTION:An alcoholic soln. contg. an organometallic compd. as a metal alkoxide having the formula M(OR)4 (wherein M is Si, Ti or Zr; and R is an alkyl) in an amount of not more than 0.7mol/l is stirred at 0-50 deg.C for 30 min-100hr to hydrolyze the compd. After the separation of the solvent, the product is dried and optionally fired at 300-1,000 deg.C to obtain fine spherical particles of an inorg. oxide which have an average particle size of 0.05-2mum and in which the standard deviation of particle diameters is 1-1.5. 0.01-5wt% said fine spherical particles are added to a polyester.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a method for improving slipperiness.

More specifically, the present invention relates to a slipping property page breaking method in which inorganic oxide spherical fine particles of uniform particle size obtained by a specific manufacturing method are added to polyester film in order to improve the slipping property of the polyester film.

(Prior art) Polyester has excellent physical and chemical properties, and therefore its polyester film is widely used for magnetic tapes, optical photography, vapor deposition, capacitors, packaging, etc. It is used.

However, despite its excellent performance, various undesirable troubles may occur during the manufacturing process. This is thought to be due to the poor cleanliness of the polyester film. Furthermore, when a polyester film is used as a magnetic tape by coating a magnetic layer on its surface, particularly good lubricity is required. this is,
If the slipperiness of the film is poor, scratches and wrinkles will occur on the film surface during film manufacturing, magnetic layer coating, or other film handling, which will cause dropouts and cause problems with the quality of the magnetic tape. . Furthermore, since it is essential for magnetic tapes to have good tape running properties, good slipping properties are required.

Conventionally, as a method of improving the slipperiness of a polyester film, forming irregularities on the film surface to lower the coefficient of friction has been carried out. For this reason, it can be roughly divided into (1)
2.) A method in which part or all of the catalyst, color inhibitor, etc. used during polyester synthesis is precipitated during the reaction process and exists as fine particles, and (2) A method in which inorganic fine particles are added externally at any stage during polyester synthesis. has been done.

However, since method (1) generates particles caused by the catalytic metal compound during the polyester synthesis reaction, it is difficult to control the particle amount and particle size, and the generation of large particles is unavoidable. There were some problems, such as difficulty.

On the other hand, as inorganic fine particles added in method (2), silica, titanium oxide, barium sulfate, silicon oxide-magnesium oxide compound, silica-alumina compound, alumina compound, glass powder, calcium carbonate, clay, mica, talc, calcium phosphate , magnesium phosphate, etc. are known, and those with an average particle size of 0.001 to 10 μm are used depending on the purpose of the polyester film (Japanese Patent Publication No. 59-8216, JP-A No. 52-364).
No. 5, etc.).

However, these conventionally used inorganic fine particles have a wide particle size distribution and most of the particle shapes are amorphous due to their manufacturing method. Taking silica fine particles as an example, the average -
9 silica having a particle size of 0.02 to 0.1 μm, and according to electron microscopic observation, the particle shape was irregular, and even if it was close to spherical, the particle size distribution was very wide.

Furthermore, as polyester films have become thinner in recent years, and this has been further accelerated by the increasing density of magnetic recording, there has been a stronger demand than ever for improvements in the slipperiness and abrasion resistance of polyester films. For this reason, many proposals have been made regarding the method of adding inert fine particles to polyester, but as mentioned above, due to limitations due to the physical properties of the added fine particles, it is difficult to achieve the homogeneous, fine, and high quality required for electromagnetic conversion characteristics. K does not give dense surface irregularities, but satisfies lubricity and abrasion resistance during film manufacturing processes, magnetic tape manufacturing processes, and magnetic tape use.
has not yet been reached.

(Problems to be Solved by the Invention) The present inventors have discovered that the problems with the prior art have been added to meet the seemingly contradictory requirements of having a polyester film surface that is smooth and also satisfies lubricity. We believe that this is based on the properties of the fine particles, and as a result of intensive study, we have arrived at the present invention.

(Means and effects for solving the problems) The present invention has the following features:
Inorganic oxide spherical fine particles with an average particle diameter in the range of 0.05 to 2 μm and a standard deviation value of the particle diameter in the range of 1 to 1.5, produced by hydrolyzing an organometallic compound in an alcoholic solution. The present invention relates to a method for improving the slipperiness of a polyester film, which comprises adding 0.01 to 5% by weight of the following to polyester.

The organometallic compound that is the raw material for the inorganic oxide spherical fine particles (hereinafter referred to as spherical fine particles) used in the present invention is a metal compound such as silicon, titanium, or zircon that contains a hydrolyzable organic group. Any material may be used as long as it can be decomposed to form an inorganic oxide, and metal alkoxides are preferably used because they are industrially easily available and inexpensive. They have the general formula M(OR)4 (where M is Si,
Ti or Zr, and R represents an alkyl group. ), but preferably the alkyl group is a lower alkyl group having up to 8 carbon atoms. Specifically, tetramethoxysilane, tetraethoxysilane, tetraisopropoxytitanium, tetrabutoxysilane, tetramethoxytitanium, tetraethoxytitanium, tetraisopropoxytitanium, tetrabutoxytitanium, tetramethoxyzircone, tetraethoxyzircone, tetraisopropoxyzircone. , tetrabutoxyzircon, tetra(2-ethylhexyl)titanate, etc., but compounds having a plurality of alkyl groups such as dimethoxyjethoxysilane, jetoxydibutoxytitanium, etc. may also be used.

Other preferred organometallic compounds include metal alkoxide derivatives. - As an example, the general formula M (O
R) Compounds in which up to three of the flukoxide groups (OR) of 4 are substituted with carboxyl groups or β-dicarbonyl groups, or low condensates obtained by partially hydrolyzing metal alkoxides or the above alkoxide-substituted compounds. etc.

Other organometallic compounds include, for example, titanium or zircon heptacylate compounds such as zirconium acetate, zirconium oxalate, zirconium lactate, titanium lactate; titanium acetylacetonate, zircon acetylacetonate, titanium octylene glycolate, zircon acetylacetonate; Examples include glycols of titanium or zircon such as titanium triethanolaminate, and chelate compounds such as β-diketones, hydroxycarboxylic acids, ketoesters, ketoalcohols, aminoalcohols, and quinolines.

The spherical fine particles (5) are mainly made from the organometallic compound of silicon, titanium, and/or zircon, but also contain sodium, potassium, rubidium, cesium, magnesium, calcium, strontium, barium, and boron. By hydrolysis in the coexistence of organometallic compounds or inorganic salts such as aluminum, gallium, and indium, fine particles of a composite of silicon, titanium, and/or zircon oxides and oxides of the above metals can be obtained. At that time, silicon, titanium and /-1! It is preferable that the proportion of oxide of zircon or zircon be 70% or more in terms of atomic ratio.

The above-mentioned organometallic compound is added and mixed into an alcoholic solution and hydrolyzed, and the addition method can be any method such as all at once or divided. In this case, the final concentration of the solution of the organometallic compound is preferably 0.7 mo I/1 or less.

If this concentration exceeds 0.7 mol/l, it may become impossible to stably obtain spherical fine particles (2) having the particle size range described above, which are effective in the present invention.

As the alcohol in the alcoholic solution, methanol, ethanol, inglobanol, butanol, isoamyl alcohol, ethylene glycol, phlopylene gellicol, etc. are used singly or in a mixture. Dioxane, diethyl ether, ethyl acetate, benzene,
It is also possible to partially mix organic solvents such as toluene and hexane.

Water necessary for hydrolysis is included in the alcoholic solution! Let them coexist. This water content affects the shape and diameter of the particles, so it needs to be controlled to a preferable amount.
It varies depending on the type of metal in the organometallic compound and the type of compound. Further, this water and alcohol solution is added to the above-mentioned alcoholic solution, and the mixture is stirred at a temperature of 0 to 50°C, preferably at room temperature, for 30 minutes to 100 hours.

At that time, for the purpose of controlling the hydrolysis rate, NH
4. Cations such as Na, 804', H2P
Anionic catalyst components such as O4- can be added.

In this way, if an organometallic compound is hydrolyzed in an alcoholic solution under appropriate conditions, spherical microparticles will be precipitated in the solution as spherical and very small inorganic oxide microparticles with a particle size distribution. do.

Some of the organic groups derived from the raw materials may remain and bond to these precipitated particles. The precipitated particles can be separated from the solution by conventionally known methods such as filtration, centrifugation, and solvent evaporation, and then dried or optionally calcined at 9300 to 1000°C to obtain the desired spherical fine particles. . Also,
In order to improve the dispersibility of the spherical fine particles in the polyester, it is important to prevent agglomeration between the particles as much as possible and to achieve monodispersion.

For this purpose, a crusher,
It is effective to loosen agglomerated particles using a conventional method such as a ball mill or a jet pulverizer.

The spherical particle diagram obtained in this way has an average particle size of 0.05
~2μm range and standard deviation value of particle size is 1~1.5
, more preferably one with a very sharp particle size distribution in the range of 1 to 1.3. If the particle size is smaller than 0.05 μm, the effect of improving slipperiness by addition is small;
If it is larger than 2.0 μm, the surface unevenness will be too large for a thin film, causing a problem.

The polyester in the present invention is a polyester having terephthalic acid or its ester-forming derivative as the main dicarboxylic acid component and a diglycol such as ethylene glycol or 1,4-butanediol or its ester-forming derivative as the main glycol component. However, the composition
It is not limited to the manufacturing method, and may be one in which loose polyester is blended.

The spherical particles may be added to the polyester before or during the polyester polymerization, or during pelletization after the end of the polymerization, or even during melt extrusion.

Spherical microparticles are usually added in powder form, but if they are added to polyester before or during polyester polymerization, they can be added in advance to some or all of the polyester raw materials that are liquid at the time of polymerization, such as ethylene glycol. It is preferable to mix and highly disperse the above-mentioned fine particles and add them in the form of a slurry or sol, since this will also result in a high degree of dispersion in the polyester, resulting in uniform dispersion and formation of uniform irregularities in the film. In order to highly disperse the fine particles in the liquid polyester raw material, conventionally known methods such as wet ball milling and ultrasonic waves are used.

Further, when added to polyester, a silane coupling agent, a titanium coupling agent, a surfactant, etc. may be used to improve dispersibility.

The amount of spherical particles added is 0.0 to polyester.
The range is 1 to 5 fiks. Added amount is 0.01 weight t
If the amount is less than 5% by weight, the effect on slip properties is insufficient, and if it is more than 5% by weight, the physical properties such as the breaking strength of the film may deteriorate, which is not preferable.

Note that the average particle diameter and standard deviation value as used in the present invention were determined by the following method.

The particle size of 100 arbitrary particles in an image taken with an electron microscope at a magnification of 100,000 times was determined by actual measurement, and the average particle size and standard deviation value were determined using the following formula.

(However, Xi indicates the b-th particle diameter, and Le is 100.) (Effect of the invention) Inorganic particles with spherical particles and a very sharp particle size distribution obtained by the specified manufacturing method According to the method of the present invention, which is characterized in that oxide spherical fine particles are added to polyester, homogeneous fine irregularities can be reliably and easily formed on the surface of a polyester film, and the surface is substantially smooth and slippery. A polyester film with excellent properties can be obtained.

Therefore, the polyester film obtained by the method of the present invention has excellent abrasion resistance and coatability of the magnetic layer when it is made into a magnetic tape, and is particularly suitable for manufacturing magnetic tapes with excellent electromagnetic conversion characteristics. It is.

(Examples) Hereinafter, the present invention will be explained in detail with reference to Examples, but the scope of the present invention is not limited by these Examples in any way.

Reference Example 1 161 parts of ethanol and 2.7 parts of a 28% ammonia aqueous solution were placed in a 301 glass reactor equipped with a stirrer, a dropping port, and a thermometer.
i<9 was added and mixed. The mixture was heated to 20°C±0.
While adjusting the temperature to 5°C and stirring, add tetraethoxysilane 1.
A solution prepared by diluting 0 U of ethanol with 21 L of ethanol was added dropwise from the dropping port over a period of 1 hour, and stirring was continued for 2 hours after the addition to effect hydrolysis and obtain a suspension.

At this time, the concentration of each raw material with respect to the total amount of the final solution was 0.22 mol/l of tetraethoxysilane and 2.02 mol/l of -ymmonia.
Mol/l ice water, 91 mol/l. Next, the suspension was transferred to an evaporator, and ammonia, water and ethanol were distilled off under reduced pressure at a temperature of 40° C. to obtain powdery silica particles (1a). The silica particles (1a) were fired in air at 500°C to obtain silica particles (1b).

The average particle diameter, particle diameter, standard deviation of particle diameter, and specific surface area of the obtained silica fine particles (1a) and (1b) were measured, and the results are shown in Table 1.

Moreover, according to these electron microscope images, they were spherical fine particles.

Reference Examples 2 to 6 Silica fine particles ( 2) to (3), titania fine particles (4), zirconia fine particles (5), and titania-zirconia compound fine particles (6) were obtained.The physical property measurement results such as the average particle diameter of these fine particles are shown in Table 1. .

Example 1 Silica fine particles (1a) and (2) obtained in Reference Examples 1 to 6
, (3), titania fine particles (4), zirconia fine particles (
0.5 parts by weight of each of 5) and titania-zirconia compound fine particles (6) were added to 100 parts by weight of ethylene glycol, and the mixture was ball milled to obtain a high dispersion of fine particles of ethylene glycol. Next, dimethyl terephthalate 1
0.01 parts by weight of zinc acetate was added to 0.00 parts by weight and 801 parts by weight of fine particle ethylene glycol high dispersion, and the temperature was raised to 280°C under final reduced pressure to perform polycondensation.
It was formed into a sheet using an extruder set at .degree. C., then stretched 3.5 times in the longitudinal and transverse directions at 100.degree. C., and heat-treated at 210.degree. C. for 10 seconds to obtain a polyester film with a thickness of 40 .mu.m.

Furthermore, regarding the silica fine particles (1b) obtained in Reference Example 1, 0.05 parts by weight of r-aminopropyl was added to 0.5 parts by weight of the silica fine particles (Ib) before making it into an ethylene glycol dispersion. A polyester film containing inorganic oxide spherical fine particles was obtained in the same manner as above except that it was treated with triethoxysilane.

About these polyester films, ASThi
When the static friction coefficient was measured according to the -D-1894B method, all the coefficients of static friction were 1.0 or less, indicating excellent slipperiness.

Claims (1)

[Claims] 1. A product produced by hydrolyzing an organometallic compound in an alcoholic solution and having an average particle diameter in the range of 0.05 to 2 μm and a standard deviation value of the particle diameter of 1 to 1.5. Inorganic oxide spherical fine particles within the range of 0.01 to 5
A method for improving the slipperiness of a polyester film, characterized by adding % by weight. 2. The method for improving slipperiness according to claim 1, wherein the organometallic compound is a metal alkoxide or a derivative thereof. 3. Slip properties according to claim 1, wherein the organometallic compound is mainly composed of a compound of silicon, titanium and/or zircon, and the main component is an inorganic oxide silica, titania, zirconia or a composite oxide thereof. Improvement method.