JPS63265929A - Oriented polyester film - Google Patents

Abstract

PURPOSE:To make it possible to form an oriented polyester film markedly excellent in lubricity and abrasion resistance without impairing its flatness at all, by adding specified fine particles and a specified ester compound to a polyester. CONSTITUTION:This oriented polyester film is obtained from a polyester obtained from an acid component based on terephthalic acid and a glycol component based on ethylene glycol and contains 0.005-2pts.wt. fine particles of an average particle diameter of 0.05-3mum and 0.005-2pts.wt. ester compound of an alcohol with an 8C or higher aliphatic monocarboxylic acid. The number of concavities of a major diameter >=5mum on the film surface is 100/cm<2> or smaller, and the number of coarse protrusions of the height >=0.45mum on the film surface is 100/25cm<2> or smaller.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an oriented polyester film, particularly an oriented polyester film having excellent flatness, smoothness and abrasion resistance.

<Prior art and problems to be solved by the invention> Biaxially oriented films of polyester, especially polyethylene terephthalate, have excellent mechanical properties, chemical resistance, dimensional stability, etc. for capacitors,
It is widely used as a base material in many fields, including packaging, spreading plates, electrical insulation, and photographic film.

By the way, when the film is commercialized according to the above-mentioned uses, polyester film is The surface is required to be smooth and flat. However, in general, in order to impart lubricity to a film, there is a method in which part or all of the catalyst and color inhibitor used during polyester synthesis are precipitated during the reaction process and present as fine particles on the film surface (internal particle precipitation method). ) ■ The method of adding inert particles to the polyester synthesis reaction system (external particle addition method) is often rejected, but these methods are difficult to improve because of the flatness of the film surface when trying to improve slipperiness. You lose your sexuality. On the other hand, in recent years, so-called lubricants such as low molecular weight higher aliphatic compounds have been
Various methods have been proposed for adding lubricants to polyester (lubricant addition methods), but their slipping effect is insufficient, and large protrusions or dents (more dents than the film paste) resulting from impurities contained in the lubricant have been proposed. (see Figure 1) may occur, resulting in a film surface with significantly impaired flatness.

Various uses of polyester films require the contradictory properties of slipperiness and flatness, but in addition, in recent years, abrasion resistance has become a strong requirement for base films for magnetic tapes, especially video tapes. Teru.

In other words, playback defects are caused by scraped powder on the surface of the film (hereinafter referred to as "white powder") during processing steps such as the calendering step during magnetic tape manufacturing, and white powder that occurs when the film is run many times in a video deck after being made into a Yamaki tape. Therefore, there is a strong desire to improve wear resistance.

As described above, at present, no means have been established to significantly improve lubricity and abrasion resistance without impairing flatness.

<Means for Solving the Problems> An object of the present invention is to provide a film that eliminates the above-mentioned drawbacks. That is, polyester contains fine particles and an ester compound of higher aliphatic monocarboxylic acid,
Another object of the present invention is to provide an oriented polyester film that has excellent lubricity and abrasion resistance without impairing its flatness at all. That is, the gist of the present invention is as follows. Fine particle O1θQ! ~λ parts by weight and an ester compound of an alcohol and a higher aliphatic monocarboxylic acid having ♂ or more carbon atoms. θO! Contains ~1 part by weight, and the major axis of the surface! Number of dents larger than μm is 100
/cr/i or less, and the surface height θjgμ
The number of coarse protrusions larger than m is /θO pieces/2! - An oriented polyester film characterized by:

Shio J-cho, 7 items/item 1 light 1 nifty T Me-1 te review #1 explanation However, this applies regardless of how it is manufactured. Examples include methods such as (1) performing a transesterification reaction with dimethyl terephthalate and ethylene glycol, followed by a polymerization reaction, and (2) performing a polymerization reaction after esterifying terephthalic acid with ethylene glycol.

Of course, these polyesters may be homopolyesters or copolyesters (copolymerized polyesters), and examples of copolymerized components include diethylene glycol, glopylene glycol, neopentyl glycol, polyalkylene glycol, p -xylylene glycol, /, 9t-cyclohexane dimetatool,! -Diol component of sodium sulforesorcinato, adipic acid, sepacic acid, phthalic acid, isofuric acid, 2. t-naphthalene dicarboxylic acid! Examples include dicarboxylic acid components such as -sodium sulfoisophthalic acid, polyfunctional dicarboxylic acid components such as trimellitic acid and pyromellitic acid, and oxycarboxylic acid components such as p-oxyethoxybenzoic acid.

Note that, of course, the above polyester contains known additives,
For example, antistatic agents, heat stabilizers, ultraviolet absorbers, etc.
They may be added in amounts of l and -hi that do not impair the effects of the present invention.

The fine particles in the present invention are at least one type selected from well-known internal particles, inert particles, and organic particles insoluble in polyester.

Internal particles are particles that are produced when a metal compound added during the synthesis of polyester, such as at least one compound such as a calcium compound, a magnesium compound, a lithium compound, or a phosphorus compound, is combined with the components constituting the polyester.

Inert particles are the elements listed in the Periodic Table of Elements No. 1, ■,
It is a chemically inert material selected from oxides or inorganic salts of elements in Groups ■ and ■.For example, synthetic manen is lithium calcium carbonate obtained as a natural product, wet silica (silicon dioxide), and dry silica (silicon dioxide). silicon dioxide), aluminum silicate (kaolinite), barium sulfate, calcium phosphate, talc, titanium dioxide, aluminum oxide, aluminum hydroxide, calcium terephthalate, calcium silicate, etc.

The organic particles insoluble in polyester are not particularly limited in type, and include, for example, fine powders such as fluorine-containing fine particle polymers, calcium oxalate, and crosslinked polymers.

The average particle size of the above fine particles is 0. OJ-~3 μm, preferably 0.7~-μm. 0.
0! In the case of μm thickness, the lubricity of the film is insufficient,
On the other hand, if the thickness is less than 3 μm, agglomeration of particles will occur, and even if an ester compound, which will be described later, is added, the flatness of the film will inevitably deteriorate.

The content of the fine particles is polyester 100N-
For part 1, O1θO! The amount should be ~2 parts by weight, preferably o, o or ~/part by weight, and more preferably 0,0/~0.6 parts by weight. Content is 0
If the amount is less than 2 parts by weight, the coefficient of friction between the film and the film or between the film and the metal will become high, leading to deterioration of slipperiness.On the other hand, if the amount exceeds 2 parts by weight, Particle aggregation occurs and surface roughness increases, and even if an ester compound, which will be described later, is added, the flatness of the film cannot be avoided.

Next, the ester compound of alcohol and higher aliphatic monocarboxylic acid having 2 or more carbon atoms in the present invention will be explained in detail. Note that the number of carbon atoms referred to here refers to the total number of all carbon atoms contained in the higher aliphatic monocarboxylic acid component.

One or more of the above ester compounds may be added as a mixture.

Specific examples include (1) ester compounds obtained by reacting α-olefin-derived higher aliphatic monocarboxylic acids having 2 or more carbon atoms with heptahydric or tetrahydric alcohols; (2) naturally occurring ester compounds; Examples include, but are not limited to, montan wax, carnaupawa wax, beeswax, candelilla wax, wax wax, and talc. Furthermore, the number of carbon atoms? If the ester of higher aliphatic monocarboxylic acid is less than 10%, the lubricity when formed into a film will be insufficient, which is not preferable.

The amount of these ester compounds added must be 0.00 - 2.0 parts by weight, preferably 0.0/~2,0 parts by weight, and more preferably 0.0! ~0.1 part by weight. The above content is 0.00! If the amount is less than 2.0 parts by weight, the film will hardly have lubricity, and if it exceeds 2.0 parts by weight, the surface of the film will become too rough, which is undesirable.

When added to a film, the above ester compound provides a film with superior lubricity and abrasion resistance compared to other lubricants. Particularly excellent lubricity and wear resistance are obtained when the higher aliphatic monocarboxylic acid has 18 or more carbon atoms and the ester compound has 30 or more carbon atoms in total. However, as will be explained later, in order to reduce the number of dents caused by lubricants, the total number of carbon atoms in the ester must be increased!
It is preferable that it is less than or equal to θ.

That is, a preferred ester compound in the present invention is an ester of a heptavalent or divalent alcohol and a higher aliphatic monocarboxylic acid having 18 or more carbon atoms, and the total number of carbon atoms is 3θ~! It is an ester compound where θ. A more preferable ester compound is an ester of a heptahydric alcohol having 72 or less carbon atoms and a higher aliphatic monocarboxylic acid having 1/2 or more carbon atoms, and the total number of carbon atoms is 3θ~
50 is an ester compound.

However, when the above-mentioned lubricant is added, many dents, bumps, or coarse protrusions may be generated on the film surface, which significantly impairs the flatness and becomes a fatal defect. In such cases, it is necessary to remove components that cause dents and/or large protrusions by the molecular distillation method (e.g., centrifugal, falling film, pot, etc. distillation process) proposed earlier by the present inventors. be.

The polyester film of the present invention has a major axis of 1 on its surface.
A dent of μm or more (the sectional view of the dent is shown in Figure 1).The major axis of the dent is determined by observing the film surface and measuring the longest distance from the pace surface at the dented part.
(see figure). ) is required to be 100 or less per /-, preferably ! θ pieces/cI! ! The number is preferably 30 pieces/- or less. If there are many dents with a major diameter of 1 μm or more, the number of dropouts will increase, and the preferable lx6 value is 0.0 μm on the film surface. ! Coarse protrusions larger than Hiroμm are here! - It is essential that the number is 100 pieces or less, preferably 70 pieces/2 or less, more preferably 70 pieces/2 or less! Q pieces/, 26 dl or less. θ,! ri μ
If the number of coarse protrusions of m or more increases, the number of dropouts will increase, which is not preferable.

As described above, the present invention is ideal for base films for magnetic recording media such as magnetic tapes and flat disks, which require strict flatness, smoothness, and abrasion resistance. , In addition, (1) Capacitor films such as vapor-deposited and metal foil wrapping, (2) Packaging films such as transparent and slippery, (3) Electrical disconnection films, (4) Films for plate making, (5) Photographs. It can also be applied to various uses such as films and (6) printed circuit boards.

In the present invention, the film must be oriented. If the film is not oriented, thickness unevenness, rigidity and dimensional stability will be extremely poor.

The orientation format can be selected from known orientation formats such as -axial orientation and biaxial orientation, but biaxial orientation is particularly desirable, and a normal stretching process is employed for this.

That is, sequential biaxial stretching or simultaneous biaxial stretching (furthermore, K after these).

Re-longitudinal stretching and re-transverse stretching may be added.1. -=) and then heat-treated at a desired temperature (for example,
The method described in Publication No. 6J) will be adopted.

Examples> The present invention will be described in more detail below based on Examples and Comparative Examples, but the present invention is not limited to the following Examples unless the gist thereof is exceeded. The measurement method and evaluation method used in the present invention are as follows.

(1) Measurement of internal particle amount Polyester 10011 and 0-chlorophenol 8 oz.
After adding and heating at 120℃ for 3 hours, ultracentrifuge manufactured by Hitachi Koki ■! Centrifugation is performed using tF-72 at so, ooθrpm for 40 minutes, and the resulting particles are dried at 100°C. When the particles are measured using a scanning differential calorimeter, if a melting peak is observed in the polymer, 0-chlorophenol is added to the particles, heated and cooled, and centrifuged again. When a melting peak is no longer observed, the particles are defined as internal particles. Normally, two centrifugation operations are sufficient.

(2) Average particle diameter ρ (μm) of fine particles Measured by optical microscope or electron micrograph! It was determined by the equivalent spherical diameter of the particle at the point of θ weight. The equivalent spherical diameter is
It is expressed as the diameter of a sphere with the same volume as the particle.

(3) Average protrusion height Ra (μm) From J, BOdθ/-/9'; The method described in # was followed. The measurement was carried out using a surface roughness measuring machine model 5E-3 made by Koita Research Wr.
F was used. Stylus diameter 2μ, stylus pressure 30■, cutoff value 0.0? The rhyme and measurement length were 2.5 meters. The measurement is 7.2
Dotwise, cut the maximum value and minimum value respectively, 70
It is shown as the average value of points.

(4) Measurement of dents Aluminum is deposited on the film and observed with a differential interference microscope to obtain a plurality of photographs with a photographic magnification of 100 times. Next, the major axis can be visually observed on this photo! μm or more (second
Count the dents in Figure 1 (Figure 1) and convert to the number per -.

(5) Coefficient of kinetic friction of metal (F/Me-μd) Fixed hard chrome-plated metal roll (diameter ∆) with width 70
Wrap a sample film with a length of 300 mm in layers/35
0(θ) and apply a load of -5″3pc″r2) to one end.A, 7-7--. □degrees. The resistance force at the other end ('r1 (J)) was measured, and the coefficient of friction during running was determined using the following formula. Measurement was at 3℃ and humidity! θ
It was done under the hood.

(6) Film-film dynamic friction coefficient (F/F-μc
L) ABTM D-//Referring to the method of Tagu 63, @
/J-TlrN, length/! θ A tape-shaped sample was pulled at a speed of 2 at a temperature of 23°C and a humidity of 0%.
0 dragon/min, chart speed 7.2θ north/min, applied load 103. The film-film kinetic friction coefficient was measured under the following conditions:

(Evaluation of abrasion resistance) A film with a width of 10 cm was run over a length of 200 m using the running system shown in Fig. The amount of wear on the fixing pin was detected visually (If) using a tension pickup, and the initial tension was about 3009, and the angle θ of the wrapping between the film and the pin was /350.

Rank (to) layering is not recognized at all.

Rank: ○ Very little layering is observed, but there is no problem in practical use.

Rank Δ The amount of adhesion is somewhat large and may cause problems if used for a long time.

Rank X: The amount of adhesion is large and it is difficult to use it practically.

(8) Height 0. ! Measurement of the number of coarse protrusions of Z μm or more Aluminum was deposited on the surface of the film and measured using a three-beam interference microscope. Measurement wavelength 0! The number of interference fringes of the first order or higher in μm is shown in terms of 2J (per J). However, in the case of dents (Fig. 1), these were excluded as confirmation waves using a differential interference microscope.

(9) Formation of magnetic layer (forming into a-air tape) First, a polyester film dimagnetic layer was coated by a conventional method. Namely, 20,250 parts by weight of γ-Fθ, ¥0 parts by weight of polyurethane resin, 1 part by weight of nitrose/L/l:l-su/j, 20 parts by weight of vinyl chloride-hinyl acetate copolymer, 7 parts by weight of lecithin, methyl ethyl ketone. 2. Mix O heavy cover part 2 and acetic acid butyl λ70 heavy cover part 2 and mix in a ball mill.
After kneading for several hours, 72 parts by weight of a polyisocyanate compound was added to form a magnetic paint, which had a dry thickness of μmK.
It was applied to the film to make it look like this.

Next, when the paint was not sufficiently dry, it was magnetically oriented using a conventional method, and then placed in an oven for drying and curing. The magnetic tape thus obtained was subjected to supercalender treatment and slit into tapes with a width of % inch.

α1 Electromagnetic conversion characteristics of magnetic tape (VTR head NV-
The following magnetic tape characteristics were regularly evaluated using a 37θθ video deck.

ot Electromagnetic Conversion Characteristics VTR Head Output) The VTR head output at a measurement frequency of Z megahertz was measured using a herring scope and evaluated on a graded basis.

◎ Very good ○ Good Δ Defective × Totally defective 0 Number of dropouts: The number of dropouts in μ5ec-λOclB was measured for about -0 minutes, and the comparative example sample in Table 1 was set at 80, and the relative values are displayed.

The more the better.

■ Orbitability of magnetic tape As a measure of the running stability of the videotape obtained by the method (9) above, the static friction coefficient of the diamagnetic north surface is A',
STM D-//94t-f? It was measured by the method of

Measurements were made using a regular deck, and here are the results! Evaluated in stages.

! Very good Z Better than normal 3 Normal. Can withstand use for video.

-Less than normal. For video use I can't stand it for use.

/　Marita〈Inferior.

Example / 10 θ parts by weight of dimethyl terephthalate, 70 M parts by ethylene glycol, 0.7 parts by weight of lithium acetate and 0.02 parts by weight of calcium acetate hydrate were placed in a reactor and heated to raise the temperature, and methanol was distilled off to form an ester. An exchange reaction was performed. The reaction starting temperature is /! Set the temperature to θ℃ and the time required to reach the reaction starting temperature is 23! ℃ to substantially complete the transesterification reaction.

Next, an ethylene glycol solution containing 0.03 part by weight of triethyl osphate θ and 0.03 part by weight of phosphoric acid was added, and then 4t! of antimony trioxide O6θ! After adding parts by weight, a polymerization reaction was carried out according to a conventional method.

That is, after adding antimony trioxide, the temperature of the reaction system was gradually increased to reach 2rj''C, and the pressure was gradually reduced from normal pressure to finally reach H9. After a period of time, the pressure in the system was reduced to normal pressure. to obtain polyester chips (polyester A
).

Polyester A contained 0.2 parts by weight of fine particles (average particle size 0, μm 1, containing calcium element, lithium element, and phosphorus element) per 10 parts by weight of polyester. Next, 100 parts by weight of the following compound (1) was added to 00 parts by weight of chip-shaped polyester Al, and kneaded.
Extrusion was performed to obtain a high concentration master chip (polyester B).

a, c(oHt-), aH(am,)coo(c4),
, an.

(Mixture consisting of n-/ri, 2/, , 2j, 27) (1) The polyesters A and B thus obtained were selected in appropriate amounts and combined and blended according to the composition shown in Table 1. , dried.

Next, this polyester composition was extruded into a sheet from an extruder at 220° C., and an amorphous sheet was obtained using an electrostatic cooling method.

After obtaining the amorphous sheet, it was stretched by 3.2 times in the longitudinal direction and by a, O times in the transverse direction, and heat treated at 1.2/J-'C until the thickness/! A biaxially stretched film of μm was obtained.

The obtained results are shown in Table 1 (the same applies to the following examples).

EXAMPLE 2 parts by weight of the following compound (It) were added to 1 part of polyester hioOM'J in the form of cochips, and the mixture was kneaded and extruded to obtain high-density master chips (polyester C).

H,O(0H2-)In(H(OHs)Coo (C!
H2), (H.

(Mixture consisting of m-j/, j3, 31.j)
(■) Select appropriate amounts of each of the polyesters A and O obtained in this way to have the composition shown in Table 1, combine and blend them, dry, and then proceed in the same manner as in Example 1. A μm thick film was obtained.

Example 3 8 parts by weight of dimethyl terephtasy, 60 parts by weight of ethylene glycol, and vinegared rice magnesium/tetrahydrate o, o
9z parts were placed in a reactor, heated to raise the temperature, methanol was distilled off, and transesterification was carried out. After a while from the start of the reaction, the temperature was raised to 230°C, and the transesterification reaction was substantially completed. . Next, 0.6% by weight of carbonate Lucicum particles with an average particle size θ of 2 μm, which had been previously crushed, classified, and filtered, were added, and o and o y parts by weight of ethyl acid phos were added, followed by a polycondensation reaction in the evening. A polyester chip was obtained (Polyester D).

Next, polyester chips were obtained (polyester E) without adding calcium carbonate and using the same conditions as those for producing polyester D (polyester E).

Next, 2M parts of the above compound (I) was added to the chip-shaped polyester D/θOM NH, and the mixture was kneaded and extruded.
A high-concentration master chip was obtained. Appropriate amounts of each were selected and combined and blended so as to have the composition shown in Table 1. After drying, a film with a thickness of !μm was obtained in the same manner as in Example.

Comparative Example/ 2 parts by weight of sodium stearate was added to 00 parts by weight of chip-shaped polyester Al, and the mixture was kneaded and extruded to obtain a high concentration master chip (Polyester G).

Appropriate amounts of each of the polyesters A and G obtained in this manner are selected and combined to give the composition shown in Table 1, and after drying, the same procedure as in Example 1 is carried out. A μm thick film was obtained.

Comparative Example 2 parts by weight of sodium montanate were added to 00 parts by weight of cochip-shaped polyester Al, and the mixture was mixed and extruded to obtain a high concentration master chip (Polyester H).

The polyesters A and H obtained by smelting were selected and blended in appropriate amounts so as to have the compositions shown in Table 7. After drying, a film with a thickness of /j ltm was obtained in the same manner as in Example /. Ta.

Comparative Example 3 After drying polyester A in the form of chips, the procedure was carried out in the same manner as in Example /! A μm thick film was obtained.

Comparative Example Polyesters D and E were selected and blended in appropriate amounts so as to have the compositions shown in Table 1. After drying, the same procedure as in Example 1 was carried out. A μm thick film was obtained.

The following can be seen from the table. First, by comparing Comparative Example / and Comparative Example 3, and Comparative Example - and Comparative Example 3, it can be seen that a film with improved flatness, smoothness, and abrasion resistance has not been obtained. On the other hand, the film of the present invention has flatness, slipperiness,
It can be seen that it has excellent wear resistance and is extremely useful especially as a magnetic recording medium.

〔Effect of the invention〕

As detailed above, the oriented polyester film of the present invention has extremely excellent flatness, lubricity, and abrasion resistance, and is suitable for various uses, particularly as an oriented polyester film for magnetic recording media.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing depressions and protrusions on the surface of the polyester film of the present invention. In the figure, / represents the base surface, and = represents the protrusion. FIG. 2 is a diagram showing the major axis of the indentation of the polyester of the present invention. In the figure, the hatched area represents a recessed area, and the white area indicated by a slash (/) represents a protruding area. FIG. 3 is a schematic diagram showing a traveling system for evaluating wear resistance, in which (1) is a fixed bottle and (II) is a Tensilon pickup. Applicant Diafoil Co., Ltd. Agent Patent Attorney Hase - Others/Names

Claims (3)

[Claims] (1) Obtained from a polyester containing terephthalic acid as the main acid component and ethylene glycol as the main glycol component, 0.005 to 2 parts of fine particles with an average particle size of 0.05 to 3 μm are added to 100 parts by weight of the polyester. Contains 0.005 to 2 parts by weight of an ester compound of alcohol and a higher aliphatic monocarboxylic acid having 8 or more carbon atoms, and has a long diameter of 5 μm on the surface.
The number of the above dents is 100 pieces/cm^2 or less, and the number of coarse protrusions with a surface height of 0.54 μm or more is 10
An oriented polyester film characterized in that the number of pieces is 0 pieces/25 cm^2 or less. (2) A patent characterized in that the ester compound is an ester of a monovalent or tetravalent alcohol and a higher aliphatic monocarboxylic acid having 18 or more carbon atoms, and has a total number of carbon atoms of 30 to 50. The oriented polyester film according to claim 1. (3) The ester compound is an ester of a monohydric alcohol having 17 or less carbon atoms and a higher aliphatic monocarboxylic acid having 18 or more carbon atoms, and the total number of carbon atoms is 3.
The oriented polyester film according to claim 1, wherein the polyester film has a molecular weight of 0 to 50.