JPH0144207B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing an easily slippery biaxially stretched polyester film having a continuous coating film having a large number of microprojections on the film surface. Polyester films, especially biaxially oriented polyethylene terephthalate films, have excellent mechanical properties, heat resistance, and chemical resistance.
As a material for magnetic tape, photographic film, packaging film, metallizing film for capacitors, electrical insulation film, transcription film, etc.
The growth in demand has been particularly remarkable recently. However, in order to smoothly produce polyester films and apply them to the above-mentioned uses, it is necessary to improve the slipperiness of polyester films. In other words, if the slipperiness of the film is insufficient, especially in the case of a thin polyester film, it will cause serious problems in the winding, rewinding, coating, slitting, etc. operations, such as the occurrence of wrinkles during winding or the attraction of dust due to generated static electricity. This results in undesirable phenomena. For example, when various molded products manufactured by applying pressure molding or vacuum forming to unstretched or uniaxially stretched films of polyethylene terephthalate are stacked on top of each other, if the surface smoothness is insufficient, the molded products may overlap each other. It cannot be extracted smoothly, and therefore the ease of assembly line work in the processing process is significantly reduced. Conventionally, as a means to improve the slipperiness of polyester films, films were formed using polyester to which microparticles of various fillers such as silicon oxide, kaolin, talc, calcium carbonate, or alumina were added, and then a biaxial stretching process was performed. Attempts have been made to utilize the fact that the filler protrudes from the film surface as minute protrusions when the film thickness decreases. Similarly, as a technique for improving slipperiness using microprotrusions, a method is also known in which a catalyst used during polyester polymerization is converted into particles insoluble in the polymer. Although these techniques have indeed had some success in improving the slipperiness of the film, the presence of small particles within the film composition naturally reduces the transparency of the film or There are still problems that need to be improved, such as the generation of voids. In particular, for polyester films used as materials for diazo films, metallized films, photographic films, magnetic tape films, etc., reduction in film transparency and formation of voids are serious problems. For example, video magnetic films, whose demand has been increasing rapidly in recent years, are required to have particularly excellent electromagnetic properties in order to prevent undesirable phenomena such as dropout (recording loss) and color noise. Therefore, using a polyester film as a material for such a video magnetic tape, in which filler-based microprotrusions occur almost equally on both sides of the film, improves the slipperiness of the video magnetic tape. Although this may be an improvement, voids are often generated, resulting in dropouts and color noise, which is not desirable. In other words, in a magnetic tape made from a film that has minute protrusions on both surfaces, the magnetic paint layer is formed on the minute protrusions on the surface coated with magnetic paint, so the effect of the minute protrusions is less than the influence of the magnetic paint layer. Although the magnetic coating layer rarely extends to the outer surface and forms a relatively flat magnetic coating layer surface, the microprotrusions are present on the other surface that does not have the magnetic coating layer. Therefore, in the wound magnetic tape, the microprotrusions on the other side are pressed against the relatively flat magnetic paint layer, so it is impossible to completely prevent the microprotrusions from being transferred to the magnetic paint layer. It becomes possible. In addition, films obtained by the method of forming microprotrusions often have relatively coarse protrusions based on relatively coarse particles, and such coarse protrusions are Such transcription will become even more intense. A magnetic tape having an uneven magnetic paint layer causes space loss when it comes into contact with the head of a video hard drive, resulting in dropouts and color noise. In order to improve these defects caused by microprotrusions, efforts have been made to further reduce the particle size of the microparticles, but in the end a compromise between transfer and slipperiness is required. On the other hand, unlike the above method in which microparticles are added to polyester to form microprotrusions on the film surface, a method in which a specific coating liquid is applied to both sides of a film made from polyester that does not contain such microparticles is used. Accordingly, a method has been proposed in which a worm-like film structure is formed on both sides of the film to impart slipperiness to the film. Although this method uses a specific coating solution containing at least one of silicone or styrene-butadiene rubber and a water-soluble polymer compound,
This method differs from the method of imparting slipperiness to a film by adding fine particles to polyester in that it imparts slipperiness to the film through post-treatment. However, the above method has a drawback in that sufficient slipperiness cannot be obtained unless a coating liquid is applied to both sides of the film to form a worm-like film structure on both sides of the film. In other words, as described in Table 1 of the same publication as a comparative example, when a worm-like film structure is formed on only one side of the film, the difference between the surface with and without the worm-like film structure is The coefficient of friction is still large and sufficient slipperiness cannot be obtained. In addition, the patent application filed in 1986-
No. 92789 (Special Publication No. 63-28097) describes the formula Mm (CH ₂ = CHCOO) n・Xi [where M: metal such as Ca, Mg, Al, Sn, Zn, Na, etc. m: number n of 1 and 2. : Number of 1 to 6 X: Cl, -OH i: Number of 0 or 1 to 5. ] An aqueous composition containing an acrylic acid metal salt represented by the formula, polyethylene glycol, and polyethylene glycol diglycidyl ether as solid components is applied to the surface (one side) of a polyester film before crystal orientation is completed, and then stretched, An easily slippery polyester film has been proposed in which the crystal orientation of the film is completed through a heat setting process, and during this process, mountain-like fine folds are formed in the coated layer of the film by reaction of the solid components. An object of the present invention is to provide a novel method for producing an easily slippery biaxially oriented polyester film having, on at least one surface of the film, a coating consisting of a continuous specific composition having a large number of microprotrusions. It's about doing. Another object of the present invention is that the preferred slippery polyester film of the present invention has a continuous coating with a large number of microprotrusions only on one side of the film, and no such coating layer on the other side of the film. An object of the present invention is to provide a method for producing a biaxially oriented polyester film having a dual structure and having no flat surface and the other surface being substantially flat. Still another object of the present invention is to provide an easily slippery biaxially oriented polyester film that does not cause or substantially does not cause transfer to a degree that is a nuisance for various uses such as magnetic tapes. The purpose is to provide a manufacturing method. Still another object of the present invention is to prepare the easily slippery biaxially oriented polyester film of the present invention through a series of consecutive steps of extruding molten polyester through a slit to form an unstretched thin film, uniaxially stretching, and further biaxially stretching. To provide an industrially extremely advantageous manufacturing method by incorporating a procedure for forming a continuous coating layer having a large number of microprotrusions on the film surface without disturbing the continuous flow of the film. It's about doing. Further objects and advantages of the invention will become apparent from the description below. According to the present invention, (A) the following general formula () Here, Me is a divalent to hexavalent metal ion,
R is a hydrogen atom or a methyl group, X is an equivalent of an anion, y is a number from 1 to 6, and z
is a number from 0 to 2, w is a number from 0 to 8,
p is a number equal to the sum of y + 2z + w divided by the valence of Me, provided, however, that when y is a number of 2 or more, multiple R
and when w is a number of 2 or more, the plurality of Xs may be the same or different, and R is a methyl group.

[Formula] can be contained in the molecule in an amount of 2 or less per Me, and (B) a film-forming polymer compound, a monomer thereof, or An aqueous solution or water containing a mixture of, provided that when R in the above general formula () is a hydrogen atom and Z is 0, the film-forming polymer compound is not polyethylene glycol or polyethylene glycol diglycidyl ether. The dispersion is applied to one or both sides of a running polyester film before the crystal orientation is completed, and then, before the crystal orientation is completed, the coating film is heated to form a substantially shape-retaining film. This is achieved by a method for producing an easily slippery biaxially stretched polyester film, which is characterized in that the film surface is transformed into microprotrusions on the surface of the film. In the above general formula (), Me is a divalent to hexavalent metal ion. Such metal ions include:
Ions of metals in periods 3 to 4 of groups 1 to 4 of the periodic table are preferred. Among others, Mg, Ca, Zn, Al, Ti
Or Mn ions are preferred. In the above general formula (), R is a hydrogen atom or a methyl group, preferably a hydrogen atom. In the above general formula (), X is one equivalent of an anion. A monoequivalent anion is not only a monovalent hydroxide ion or a halogen ion such as a chloride ion (Cl ^- ), but also a divalent anion such as 1/2 of a sulfate ion (SO ₄ ^2- ). Alternatively, it can be a trivalent anion, such as 1/3 of a phosphate ion (PO ₄ ^3- ). In the general formula (), y is a number from 1 to 6, preferably 1 to 4, z is a number from 0 to 2, preferably 0, and w is a number from 0 to 7, preferably 0 to 5.
, and p is a number equal to the quotient of the sum of y + 2z + w divided by the valence of Me. In the above formula (), when y is a number of 2 or more, even if multiple R are the same (All R are H or
CH ₃ ) or differently (the plural R is H and
(consisting of CH ₃ ) may be used. Further, when w is a number of 2 or more, the plurality of Xs may be the same (such as when all the Xs are Cl) or different (the plurality of Xs consists of OH and Cl). However, when R is CH ₃ , the group CH ₂ =C(CH ₃ )
COO can be contained in a molecule in an amount of 2 or less per 1 Me. According to the present invention, among the metal salts having the composition of the above general formula (), the following formula ()-a Here, the definition of R is the same as in the above formula (), X ¹ is the same or different and is a hydroxyl group or a chlorine atom, q is 1 to 4, and r is 2 to 5, provided that q + r = 6 A metal salt having the composition, and/or the following formula ()-b Here, Me ¹ is Ca, Mg, Zn, Ti or Mn, and t is equal to the valence of Me ¹ and is a number from 2 to 4. A metal salt having the following composition is preferably used. As the metal salt having the composition of the above formula (),
For example, Al ₂ (CH ₂ = CHCOO) ₄ Cl ₂ , Al ₂ (CH ₂ =
CHCOO) ₃ Cl ₃ , Al ₂ (CH ₂ =CHCOO) ₄ (OH) ₂ ,
Al ₂ (CH ₂ = CHCOO) ₄ (OH)Cl, Al ₂ (CH ₂ =
CHCOO) ₂ (OH) ₂ Cl ₂ , Al(CH ₂ =CHCOO) ₃ ,

[Formula] Mg (CH ₂ = CHCOO) ₂ , Zn (CH ₂ = CHCOO) ₂ ,

[Formula] O) ₂ , Ti (CH ₂ = CHCOO) ₄ , Al ₃ (CH ₂ =
CHCOO) ₄ OCl ₃ , etc. Among these metal salts, some of the aluminum metal salts are already known (Japanese Patent Publication No. 52-32970). The metal salt of the above general formula () is generally water-soluble, but the water solubility generally decreases as y increases. Furthermore, salts in which R is a methyl group generally have lower water solubility than corresponding salts in which R is a hydrogen atom. When R is a hydrogen atom and y is 4 or less, or when R is a methyl group and y is 2 or less, an aqueous solution with a suitable concentration that can be used in the present invention is provided. In the present invention, a film-forming polymer compound, a monomer thereof, or a mixture thereof is used together with the metal salt of the general formula (). However, when R in the above general formula () is a hydrogen atom and Z is 0, the film-forming polymer compound is not polyethylene glycol or polyethylene glycol diglycidyl ether. As the film-forming polymer compound, a substantially linear, water-soluble, water-swellable or water-dispersible compound is preferably used. Examples of water-soluble polymer compounds include polyvinyl alcohol, water-soluble melamine resin, water-soluble urea resin, polyacrylamide, polymethacrylamide, phenol resin (e.g. resol resin), poly(C ₂ - _{C 4} ) alkylene glycol (e.g.
Polyethylene glycol, polypropylene glycol, polytrimethylene glycol, polytetramethylene glycol, polyethylene glycol/
polypropylene glycol block copolymer),
Sodium polyacrylate, sodium polymethacrylate, starch, hydroxyalkyl cellulose (e.g. hydroxyethyl cellulose, hydroxypropyl cellulose), polyvinylpyrrolidone, water-soluble alkyd resin, copolyester containing sodium sulfonate group, polyacrylic acid containing hydroxyl group Esters (e.g., copolymers of methyl acrylate and hydroxyethyl arylate), aliphatic mono- or polyglycidyl ethers (e.g., ethylene glycol diglycidyl ether, diethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, etc.), polystyrene sulfonic acid Examples include soda and water-soluble silicone resin. Among these, polymer compounds having aliphatic hydroxyl groups are preferably used. Examples of water-swellable or dispersible polymer compounds include vinylidene chloride copolymers (e.g., vinylidene chloride and vinyl chloride copolymers),
Vinyl chloride copolymers (e.g. copolymers of vinyl chloride and vinylidene chloride), acrylic ester copolymers (e.g. copolymers of methyl acrylate and methyl methacrylate), vinyl acetate copolymers (e.g. vinyl acetate copolymers) and ethylene), carboxyl group-containing copolyesters, sulfonic acid (salt) group-containing copolymers, maleic anhydride copolymers (e.g. copolymers of maleic anhydride and vinyl chloride, vinyl acetate) Alternatively, epoxy resin can be used. These water-soluble, water-swellable or water-dispersible polymer compounds are known per se. Monomers that provide these polymer compounds are also known, and these monomers can also be used in the present invention. Such monomers include, for example, the formula CH ₂ =C
(R ₁ )COOR ₂ , where R ₁ is a hydrogen atom or a methyl group, R ₂ is -(CH ₂ )n-OH, and n is 2 or 3; an acrylic monomer containing a hydroxyl group; formula CH ₂ = C(R ₁ )COON(R ₄ )(R ₅ ),
Here, R ₁ is a hydrogen atom or a methyl group, R ₄ ,
Acrylamide monomers, such as N-hydroxymethylacrylamide and N,N-dihydroxymethylacrylamide, in which R ₅ is the same or different hydrogen atom or hydroxymethyl group; Formula

[Formula] Here, R ₆ is an aliphatic hydrocarbon residue and m is a number from 1 to 4. Epoxy compounds such as glycerin diglycidyl ether, allyl glycidyl ether and trimethylolpropane triglycidyl ether; containing sulfonic acid groups vinyl compounds such as sodium styrene sulfonate or potassium; salts of acrylic acid or methacrylic acid such as sodium acrylate or sodium methacrylate; or vinyl-tris(alkoxyalkoxy)silanes such as vinyl-tris(β-methoxyethoxy)silane, or γ -Ureidopropyltrisethoxysilane and the like. In the present invention, the metal salt (A) having the composition of the above formula () and the above film-forming polymer compound, its monomer, or a mixture thereof (B) are coated on the film surface as an aqueous solution or an aqueous dispersion ( coating) Whether it is an aqueous solution or an aqueous dispersion depends on the metal salt or polymer compound used, the desired concentration, or the prepared concentration, but the important thing is that even if it is in an aqueous dispersion state, it will be dispersed. particles are very small (preferably dried on a film)
(with a particle size of 1.0μ or less). Therefore, their aqueous solutions or dispersions are usually advantageously prepared by applying them to a homogenizer and further applying them to an ultrasonic disperser. In order to make an aqueous solution or dispersion, if necessary, an emulsifier,
A dispersant or the like can also be used. According to the present invention, the aqueous solution or aqueous dispersion thus prepared is continuously applied to the film surface of a running polyester film, that is, a running unstretched or uniaxially stretched polyester film before crystal orientation is completed. be done. The aqueous solution or aqueous dispersion at that time preferably contains the metal salt of formula () in an amount of about 0.1 to about 10% by weight, more preferably about 0.5 to about 5% by weight, and contains a film-forming polymer compound and its monomer. mer or mixture thereof, preferably about
0.05 to about 5% by weight, more preferably about 0.2 to about 2%
Contained in weight%. These aqueous solutions or dispersions are preferably applied in an amount of about 0.5 to about ¹⁰ g, more preferably about 1 to about 5 g per square meter of running film. In other words, in the biaxially stretched film finally obtained, the amount of solid content is about 0.001 to about 0.3 g per 1 m ² of the film surface,
Applicable to films running an aqueous solution or dispersion. According to the present invention, the aqueous solution or aqueous dispersion is applied to a traveling unstretched or uniaxially stretched film. Even if this aqueous solution or aqueous dispersion is applied to a film that has already been biaxially stretched and then heated,
It is not possible to produce the slippery film of the present invention having a large number of microprotrusions on the surface. According to the present invention, the aqueous solution or aqueous dispersion is preferably applied to the uniaxially stretched film immediately before the uniaxially stretched film enters the tenter for biaxial stretching and heat setting. According to the present invention, the above aqueous solution or aqueous dispersion can be applied to one or both sides of an unstretched or uniaxially stretched film. The slippery biaxially stretched film of the present invention obtained by coating on only one side has a dual surface structure in which one side has a large number of microprotrusions and the other side is smooth. , can be particularly suitably used as a material for magnetic tape. Application of the aqueous solution or aqueous dispersion can be carried out using per se known technical means, such as reverse coating (bottom feed 3-reverse, bottom-feed 4-reverse,
This can be carried out by two-roll reverse, top-feed three-roll reverse, etc.), Kissmeyer coating, gravure coating (direct gravure or offset gravure), slot die coating, curtain coating, etc. According to the present invention, the slippery film of the present invention having the above-mentioned dual surface structure preferably rolls the above-mentioned aqueous solution or aqueous dispersion from the lower surface of the uniaxially stretched film that runs substantially horizontally away from the nip roller group. It can be advantageously manufactured by a coating method using a coater. According to the present invention, the aqueous solution or aqueous dispersion coated onto the surface of the polyester film to a uniform thickness by the above method is then expanded in area as the polyester film is stretched, and heated. The water is volatilized and the film is converted into a thin solid coating layer having a large number of microprojections on the surface of the biaxially stretched film, which is firmly fixed on the surface of the biaxially stretched film. According to the present invention, the aqueous solution or aqueous dispersion is converted into a solid coating film having a large number of microprojections as described above by heating. Therefore, the fact that such a solid coating film is obtained even when using a monomer of a film-forming polymer compound suggests that the heating described above is accompanied by some kind of reaction. It will be done. Although such a reaction is not clear, it is probably a reaction involving a metal salt (A) and a film-forming polymer compound or its monomer (B), and a polymerization reaction of the monomers, and in some cases It is presumed that this reaction involves the polyester that forms the polyester film base. In any case, according to the present invention, it is a certain fact that the solid coating layer formed on the surface of the polyester film is composed of the metal salt (A) of the above formula () and the film-forming polymer compound (B). Contains at least According to the research of the present inventor, heating is absolutely necessary to form the large number of microprotrusions described above. For example, when the above aqueous solution or aqueous dispersion is applied to a uniaxially stretched film and then air-dried without heating, It was revealed that it was not possible to form a large number of microprotrusions that had substantially shape-retentive properties. According to the invention, said heating is preferably about 100
The process is carried out at a temperature of about 240° C. for about 1 to about 20 seconds.
The fact that these temperatures and times are included in the temperatures and times actually employed in the normal series of steps for producing biaxially oriented polyester, particularly in the heat-setting step, makes the implementation of the present invention extremely advantageous industrially. It shows that there is. Furthermore, according to the research conducted by the present inventors, the formation of a solid coating layer having a large number of microprotrusions may vary depending on, for example, the stretching ratio, the composition of the aqueous solution or aqueous dispersion applied to the film, or the coating amount. It has also been shown that it is influenced by For example, focusing on the shape of a large number of microprotrusions, solid coatings having microprotrusions include, for example, rock plate-like protrusions, that is, those with a lamellar structure, those with a mountain range shape,
These include those that have crepe-like folds, and those that have small grains dotted within an elliptical crettering to form protrusions. A solid coating layer having a lamellar structure is formed by a combination of a metal salt of the formula () and a certain type of water-soluble film-forming polymer compound, such as a combination of a metal salt of the formula () and a polyoxyethylene glycol with a molecular weight of 6,000 or more. It is easy to produce by using a combination of oxyethylene glycol diglycidyl ethers. The solid coating layer having mountain-like aggregation can be formed by combining, for example, Ti( _CH2 =CHCOO) ₄ and/or Al( _CH2 =CHCOO) ₃ as a metal salt of the formula () and a water-soluble film-forming polymer compound. It can be easily produced by using a combination of polyvinyl alcohol or methylolated melamine resin. The easily slippery biaxially stretched polyester film of the present invention, which has such a solid coating layer having mountain-like aggregates and a large number of microprotrusions, exhibits particularly excellent slipping properties. In particular, when the metal salt is contained in an amount of 54 to 87% by weight based on the solid content,
A coating surface having mountain range-like collections can be produced very easily. The solid coating layer with crepe-like folds can be made of, for example, Al ₂ (CH ₂ =CHCOO) ₃ Cl ₃ and eg vinyl-tris(β-methoxyethoxy)silane, γ-glycidoxypropyltrimethoxysilane, γ-amino It can be easily produced by using a combination with a silane compound such as propyltriethoxysilane. In particular, Al ₂ (CH ₂ =
When CHCOO) ₃ Cl ₃ is contained in an amount of 35 to 72% by weight based on the solid content, a coating layer with good slipperiness having crepe-like folds can be formed very easily. Furthermore, the coating surface has protrusions with small particles scattered within the circular crater, for example, Zn
(CH ₂ =CHCOO) ₂ and methylated polysiloxane or dimethyl polysiloxane diglycidyl ether, and a lubricant filler (described later) such as polytetrafluoroethylene fine particles can be easily produced. be able to. In particular, Zn (CH ₂ =
When CHCOO) ₂ is contained in an amount of 25 to 84% by weight based on the solid content, a coating having the above shape with good slip properties can be produced very easily. In the present invention, the aqueous solution or aqueous dispersion applied between the films can contain various additives in addition to the components (A) and (B). Such additives include lubricant fillers added for the purpose of providing better lubricity, and lubricant fillers (A), (B), or lubricant fillers for the purpose of improving their solubility or dispersibility, as well as their wettability with polyester films. These include surfactants, crosslinking agents, polymerization catalysts, and stabilizers such as heat stabilizers and ultraviolet absorbers. These additives are known per se. For example, lubricant fillers include fine powders of organic fillers such as polytetrafluoroethylene, polyvinylidene fluoride, polyethylene or polyacrylonitrile, or silica, titanium dioxide, alumina, kaolin, talc, graphite, calcium carbonate, feldspar or A fine powder of an inorganic filler such as molybdenum disulfide; a surfactant such as a nonionic surfactant such as polyoxyethylene nonyl phenyl ether; or a polymerization catalyst such as '-azobis(2-amidinopropane) hydrochloric acid Examples include radical polymerization catalysts such as salts, ammonium persulfate, potassium persulfate, and sodium persulfate. Since these additives do not need to be present in large amounts in the aqueous solution or dispersion used in the present invention, their particle size does not matter if they are water-soluble. However, in the case of a generally water-insoluble solid substance such as the above-mentioned lubricant filler, an average particle size of about 0.005 to 1 μm is preferably used. Additionally, these water-insoluble solid materials preferably have a specific gravity of about 3 or less to avoid settling in the aqueous dispersion. The aqueous dispersion containing the fine powder lubricant filler as described above contains protrusions based on the fine powder as part of the large number of microprotrusions on the easily slippery biaxially stretched polyester film obtained by the method of the present invention. Generates a coating surface. Such protrusions based on fine powder often provide better sliding properties than those without fine powder. Such fine powder is usually about 0.1 to about 3% by weight based on the above aqueous solution or dispersion.
It can be contained in an amount of Thus, according to the method of the present invention described above, according to the present invention, a film containing at least a metal salt having the composition of the above formula () and a film-forming polymer compound and having substantially shape retention properties is obtained. There is provided an easily slippery biaxially oriented polyester film having a continuous coating film having a large number of microprotrusions on at least one surface of the film over substantially the entire surface of the film. The term "microprotrusions that substantially retain shape" means microprotrusions whose shape is substantially retained by a frictional force that is applied to the film during use. In the present invention, microprotrusions having substantially shape-retentive properties are more specifically determined by the following formula F={1- (μk)A-(μk)B/(μk)B}×100 Here, F represents the form retention rate (%),
(μk) A is the coefficient of kinetic friction at the 20th sliding, (μk)
B is the coefficient of dynamic friction at the first time of sliding, and is defined by the form retention rate (F, %) expressed as: The microprotrusions of the film of the present invention preferably include:
It has a form retention rate (F) of 100 to about 75%. A continuous coating surface does not refer to a coating in which independent microprotrusions are formed directly on the film surface of a polyester base film, but rather a coating in which microprotrusions are formed directly on the film surface of a polyester base film. It is to be understood that it refers to the coated surface as if another continuous underlying coating layer were present. Therefore, the substantially continuous coating surface having microprojections of the present invention includes a substantially continuous base layer in contact with the film surface of the polyester film and a large number of microprojections projecting outward from this layer. It consists of Of course, the base layer and the large number of microprotrusions mentioned above are formed integrally by one application of an aqueous dispersion or an aqueous solution according to the method of the present invention. The easily slippery biaxially oriented polyester film of the present invention has a continuous coating surface having the above-mentioned microprotrusions of about 2.5 to about 200 mg, more preferably about 5 mg/m ² of the film.
~ in an amount of about 150 mg. The above continuous coating surface has an average particle size of approximately 0.005 to approximately 1μ.
When the water-insoluble solid substance preferably contains fine powder of a lubricant filler, the protrusions based on the fine powder together with the protrusions based on the metal salt and the film-forming polymer compound having the composition of formula () form the film surface. It is possible to reduce the contact area and the adhesive shearing force when the two contact with each other, thereby providing the easily slippery biaxially oriented polyester film of the present invention which has even better slip properties. The polyester base film of the easily slippery biaxially stretched polyester film of the present invention contains aromatic dibasic acids such as terephthalic acid and isophthalic acid as the main acid component and aliphatic diols having 2 to 6 carbon atoms such as ethylene glycol, trimethylene glycol, etc. It consists of an aromatic homo- or copolymer polyester containing tetramethylene glycol or hexamethylene glycol as the main glycol component, preferably polyethylene terephthalate. Techniques for making films from these polyesters are already known in the art. The easily slippery biaxially stretched polyester film of the present invention has extremely excellent slip properties, as will be explained later using specific data in Examples, and can be used in various fields where excellent slip properties are required. It is especially suitable for use as a material for magnetic tape. Hereinafter, the present invention will be explained in more detail with reference to Examples. Before that, we describe the measurement methods and definitions of various values. Various values herein are measured and defined as follows. (1) PV value: The roughened film was measured using a stylus surface roughness tester (Surcom3B) manufactured by Tokyo Seihi Co., Ltd. under the conditions of a needle radius of 2 μ and a load of 0.19 r for a film reference length of 26 mm. Magnify the longitudinal direction by 50 times and the surface roughness direction by 20,000 times, draw a chart, and draw a chart that passes through the bottom of the first valley from the highest among the straight lines parallel to the average line of the section cut out by the standard length from the cross-sectional curve. The value obtained by dividing the distance between these two straight lines by the vertical magnification is expressed in microns, and the average value of these 10 PV values is expressed. (2) CAL value Obtain a film roughness curve using the same device as in (1), cut out a part of measurement length L (reference length 2 mm) in the direction of its center line, and mark the center line of this cut out part with
The roughness curve is Y= with the direction of vertical magnification as the Y axis.
When expressed as f(x), the value given by the following equation is expressed in units of μ. RCLA=1/L∫ ^L ₀ |f(x)|dx In this measurement, the standard length is 0.25 mm, 8 measurements are taken, 3 are excluded from the direction with the largest value, and the average value of the 5 is expressed. (3) Coefficient of Dynamic Friction (Running Properties) Figure 1 is a schematic diagram for measuring the coefficient of kinetic friction μk for evaluating film running properties (device used: Japan Automatic Control K.KNJS101 model). In the drawing, 1 is the feed reel, 2 is the tension control,
3, 5, 6, 8, 9, 11 are freerolls, 4
Reference numeral indicates a tension detector (inlet), 7 a chrome-plated fixing pin (5 mmφ), 10 a tension detector (outlet), 12 a guide roller, and 18 a take-up reel. As shown in Part 1, under an atmosphere of 20℃ and 60%RH,
The film was passed through the film so that the smoothed surface was in contact with a fixed pin with an outer diameter of 5 mm at (152/180) k radians, and friction was applied at a speed of 33 cm/sec. Then, when the tension controller 2 is adjusted so that the inlet tension is 30 gr, the outlet tension T ₂ and 10 are determined, and the dynamic friction coefficient μk is calculated using the following formula. μk=0.868logT ₂ /30 The tape length to be detected was 89.1 m. (4) Scrapability While measuring the coefficient of dynamic friction, we observed whether the running condition was good or not, and at the same time observed whether there was any material deposited when the film came into contact with the fixed pin. ○ if no deposits are observed, △ if there is evidence of adhesion, × if there is a lot of deposits
(test length 891m). (5) Film friction coefficient The friction coefficient between the coated surface and the polyethylene terephthalate (untreated) film was measured using a slit parry measuring device manufactured by Toyo Tester Co., Ltd. (6) Shape retention of microprotrusions The following formula F obtained from the dynamic friction coefficient measured using a reciprocating wear tester is defined as the shape retention rate. F={1-(μk)A-(μk)B/(μk)B}×100
(%) Here F represents the form retention rate (%),
(μk)A is the coefficient of kinetic friction at the 20th sliding,
(μk)B is the coefficient of kinetic friction at the first time of sliding. Example 1 (1) 30% aqueous solution of Al ₂ (CH ₂ =CHCOO) ₃ Cl ₃ (manufactured by Asada Chemical Industry Co., Ltd., trade name P-3) 60 parts by weight (as solid content), Ti (CH ₂ =CHCOO) 10% aqueous solution of ₄
15 parts by weight (as solid content), 10 parts by weight of polyvinyl alcohol (manufactured by Shin-Etsu Chemical Co., Ltd., trade name Poval A), molybdenum dioxide (manufactured by Nippon Acheson Co., Ltd.,
Product name DAG-206) 5 parts by weight and polyoxyethylene nonyl phenyl ether (HLB=
A coating composition was prepared by sufficiently mixing 10 parts by weight of 12.8 (manufactured by Nippon Oil & Fats Co., Ltd., trade name HS208.5) first with a homogenizer and then with an ultrasonic disperser.
This coating composition was dissolved in ion-exchanged water with a pH of 7 to form a coating solution with a total solids concentration of 2% by weight. (2) Polyethylene terephthalate (heat of crystallization
9.8cal/g) was extruded from the nozzle using an extruder, and this was made into an extruded film with a thickness of 152μ while applying electrostatic charge on a drum cooled to 40℃, and then this was extruded on a metal roll heated to 93℃. It was stretched 3.6 times in the longitudinal direction. Then, just before the uniaxially stretched film reached the tenter, the above coating liquid was uniformly applied onto one side of the film from a coater head consisting of three rolls. The coating amount of the coating liquid was approximately 2.3 g per 1 m ² of the above-mentioned uniaxially stretched film.
equivalent to approximately 0.0129 g per ^m2 ). The uniaxially stretched film that has been coated on one side is then led into a tenter and stretched 3.5 times in the transverse direction at 101℃, and then
It was heat-set at 225°C for 6.3 seconds (corresponding to a total of 11 seconds of heating time for the film coated with the coating solution). Thus, the biaxially stretched film could be wound with a tension of 9.8 kg without wrinkles. The film thus obtained (the film of the present invention) was microslit to a width of 1/2 inch to produce 52 tapes of 500 mg each. During this time, the film was successfully slit without any trouble. Table 1 shows the surface properties, runnability, etc. of the film of the present invention. As is clear from the comparison with the film obtained in the comparative example (without the coating liquid applied),
It can be seen that the film of the present invention has extremely excellent basic properties, especially as a base film for magnetic tape. Example 2 (1) 66 parts by weight of an aqueous solution containing Al ₂ (CH ₂ =CHCOO) ₃ Cl ₃ and polyacrylamide with a solid content concentration of 8.4% (manufactured by Asada Chemical Industry Co., Ltd., trade name KAL#13) water-soluble melamine condensate containing methylolated melamine as the main component (manufactured by Dainippon Ink Industries, Ltd., trade name Watersol S-695) 7
Part by weight, quarternized polyethylene (Daikin Industries, Ltd.)
manufactured by Lubron L-2, average particle size 0.2μ) 13
Parts by weight and nonionic surfactants NS208.514
Using parts by weight, a coating solution having a total solids concentration of 1.5% by weight was produced in the same manner as in Example 1 (1). (2) Other than using this coating liquid and applying this coating liquid to one side of a uniaxially stretched film in an amount of about 3 g/m ² (this amount corresponds to about 0.0129 g per 1 m ² for a biaxially stretched film) A biaxially stretched film of the present invention was produced in exactly the same manner as in Example 1 (2). Similar to the film of the present invention in Example 1, this biaxially stretched film could be wound with a tension of 9.8 kg without wrinkles. Furthermore, the film could be slit without any trouble. The surface characteristics, running properties, etc. of the film of the present invention are shown in Table 1. Example 3 (1) 40 parts by weight of a 30% aqueous solution of Al ₂ (CH ₂ =CHCOO) ₃ Cl ₃ (as solid content), vinyl-tris (β-methoxyethoxy) silane (manufactured by Nippon Unitika Co., Ltd.,
Product name A-172) 33 parts by weight, γ-ureidopropyltriethoxysilane (manufactured by Nippon Unitika Co., Ltd.,
15 parts by weight of product name A-1160), 2 parts by weight of 2,2'-azobis(2-amidinopropane) hydrochloride (manufactured by Wako Pure Chemical Industries, Ltd., product name V-50) and nonionic surfactant. Using 10 parts by weight of NS208.5, a coating liquid having a total solids concentration of about 2% by weight was produced in the same manner as in Example 1 (1). (2) Using this coating liquid, apply this coating liquid to one side of a uniaxially stretched film in an amount of approximately 2.4 g/m ² (equivalent to approximately 0.0135 g/m ² per 1 m ² for a biaxially stretched film). Except for this, a biaxially stretched film of the present invention was produced in exactly the same manner as in Example 1 (2). Similar to the film of the present invention in Example 1, this biaxially stretched film could be wound with a tension of 9.8 kg without wrinkles. Furthermore, this film could be slitted without any trouble. The surface characteristics and running characteristics of the film of the present invention are shown in Table 1. Example 4 (1) 30% aqueous solution of Al ₂ (CH ₂ =CHCOO) ₄ (OH) ₂ (manufactured by Asada Chemical Industry Co., Ltd., trade name P-8) 60 parts by weight (as solid content), polyvinyl alcohol Using 10 parts by weight of (Poval A), 5 parts by weight of molybdenum disulfide, and 5 parts by weight of the nonionic surfactant NS 208.5, the total solid content concentration was approximately 2.5% by weight in the same manner as in (1) of Example 1. A coating solution was prepared. (2) Except for using this coating liquid and applying this coating liquid to a uniaxially stretched film in an amount of about 4.1 g/m ² (this amount corresponds to about 0.0286 g per 1 m ² for a biaxially stretched film). A biaxially stretched film of the present invention was produced in exactly the same manner as in Example 1 (2). This biaxially stretched film, like the film of the present invention in Example 1, could be wound up well. The surface characteristics, running properties, etc. of the film of the present invention are shown in Table 1. Comparative Example 1 A biaxially stretched film was produced in the same manner as in Example 1 (2) without applying the coating liquid. however,
This biaxially stretched film could not be wound with a tension of 9.8 kg. In other words, wrinkles occur due to poor mutual slippage between the films, and once these wrinkles occur, they propagate and concentrate one after another to the surface layer, resulting in one side of the roll end becoming hard and the center becoming soft. It was wrapped in a shape that could hardly be considered a product. Therefore, I tried to set the winding tension to the maximum and wind it at 4.68 kg, but the ends were not even and there were wrinkles in the winding, so I still couldn't get a perfectly rolled shape. I also tried to make a microslit with a width of 1/2 inch, but it was impossible.

【table】

【table】 Example 5 (1)

30% aqueous solution of [Formula] (manufactured by Asada Chemical Industry Co., Ltd., no product name) 60 parts by weight (as solid content), polyethylene glycol (PEG200)
Same as Example 1 (1) using 25 parts by weight, 10 parts by weight of polyoxyethylene diglycidyl ether (NER010), 5 parts by weight of molybdenum disulfide, and 5 parts by weight of nonionic surfactant (NS208.5). A coating liquid having a total solids concentration of about 2.5% by weight was produced. (2) Other than using this coating liquid and applying this coating liquid to a uniaxially stretched film in an amount of about 4.1 g/m ² (this amount corresponds to about 0.0286 g per 1 m ² for a biaxially stretched film) A biaxially stretched film of the present invention was produced in exactly the same manner as in Example 1 (2). The results are shown in Table 2. Example 6 (1) 40% aqueous solution of Mg (CH ₂ =CHCOO) ₂ (manufactured by Asada Chemical Industry Co., Ltd., no trade name) 55 parts by weight (as solid content),

20 parts by weight (as solid content) of a 50% aqueous solution of [Formula] (manufactured by Asada Chemical Industry Co., Ltd.), 10 parts by weight of polyvinyl alcohol (Poval A)
A coating solution with a total solids concentration of about 2% by weight was prepared in the same manner as in (1) of Example 1 using 5 parts by weight of molybdenum disulfide and 10 parts by weight of a nonionic surfactant (NS208.5). was manufactured. (2) Other than using this coating liquid and applying this coating liquid to a uniaxially stretched film in an amount of about 2.4 g/m ² (this amount corresponds to about 0.0135 g/m ² for a biaxially stretched film) A biaxially stretched film of the present invention was produced in exactly the same manner as in Example 1 (2).
The results are shown in Table 2. This biaxially stretched film could be well wound up with a tension of 9.8 kg, and it was also possible to form microslits into 1/2″ width. Interference micrograph (×
400) showed numerous microprotrusions. Example 7 (1) 60 parts by weight of a 30% aqueous solution of Al ₃ (CH ₂ -CHOO) ₄ OCl ₃ (as solid content), 10 parts by weight of polyvinyl alcohol (Poval A), 5 parts by weight of molybdenum disulfide
Parts by weight, 10 parts by weight of polyoxyethylene diglycidyl ether (manufactured by Nagase Sangyo Co., Ltd., trade name NER 010) and nonionic surfactant NS 208.5 5
Using parts by weight, a coating liquid having a total solids concentration of about 2.5% by weight was produced in the same manner as in Example 1 (1). (2) Biaxial stretching of the present invention was carried out in the same manner as in (2) of Example 1, except that this coating liquid was used and the coating liquid was applied to the uniaxially stretched film in an amount of about ^4.1 g/m 2 . produced a film. This biaxially stretched film, like the film of the present invention in Example 1, could be wound up well. The results are shown in Table 2. Example 8 (1) 70 parts by weight (as solid content) of a 30% aqueous solution of Al ₂ (CH ₂ =CHCOO) ₂ (OH) ₂ Cl ₂ (manufactured by Asada Chemical Industry Co., Ltd.), water-soluble copolyester (large japan ink
Co., Ltd., product name FINETEX-ES 650) 5 parts by weight,
Using 10 parts by weight of polyvinyl alcohol (Poval A), 5 parts by weight of molybdenum disulfide, and 10 parts by weight of a nonionic surfactant (NS208.5), the total solid concentration was determined in the same manner as in (1) of Example 1. A coating solution of about 2% by weight was produced. (2) Other than using this coating liquid and applying this coating liquid to a uniaxially stretched film in an amount of about 2.35 g/m ² (this amount corresponds to about 0.0132 g/m ² for a biaxially stretched film) A biaxially stretched film of the present invention was produced in exactly the same manner as in Example 1 (2). The results are shown in Table 2. This biaxially stretched film could be successfully wound with a tension of 9.8 kg. We were also able to successfully form microslits with a width of 1/2". A differential interference microscope photograph (x400) of the treated surface of this film after aluminum vapor deposition showed many microscopic protrusions.

[Table] Example 9 Polyethylene terephthalate containing no inorganic filler with an intrinsic viscosity of 0.62 measured in orthochlorophenol at 25°C (heat of crystal fusion 9.8 cal/g)
Use an extruder to extrude it from the base and make it 40
An extruded film with a thickness of 1545μ was obtained while applying electrostatic charge on a drum cooled to ℃, and then this was
It was stretched 3.6 times using a metal roll heated to 93°C.
The same coating liquid as produced in Example 2 (1) was applied to the uniaxially stretched film according to the method described in Example 1 (2), and the coating amount was 0.0129 g/m ² (as solid content).
A biaxially stretched film (polyethylene terephthalate film thickness: 125 μm) was obtained. On the other hand, for comparison, a biaxially stretched film (blank) was produced in exactly the same manner as above without applying the coating liquid. In this comparative example, winding became possible only after the tension was made considerably smaller. When this film (blank) was stored as a wound roll, Newton rings due to adhesion were formed here and there in the areas where the films were in close contact with each other, and were observed as a stain-like pattern. Such a pattern was not observed in the biaxially stretched film of the present invention. Cut each film into B4 size and display on TV.
150 videos were drawn in the same way, stacked on top of each other, and viewed through from directly above, about 60 cm away from the top sheet. When a comparison film (blank) was used, a partially wet stain-like pattern was observed. When I took a photo, this pattern appeared vaguely. On the other hand, such a pattern was not observed in the film using the film of the present invention. It was found that the film of the present invention has sufficient optical properties as a projection material for animation.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of an apparatus for measuring the coefficient of dynamic friction. In the drawing, 1 is a feed reel, 13 is a take-up reel, and the coefficient of dynamic friction can be calculated from the tension at tension detectors 4 and 10.

Claims (1)

[Claims] 1 (A) The following general formula () Mep (CH ₂ = CRCOO) y (O) z (X) w ... () where Me is a divalent to hexavalent metal ion,
R is a hydrogen atom or a methyl group, X is an equivalent of an anion, y is a number from 1 to 6, and z
is a number from 0 to 2, w is a number from 0 to 8,
p is a number equal to the quotient of the sum of y+2z+w divided by the valence of Me, provided, however, that when y is a number of 2 or more, multiple R
When w is a number of 2 or more, the plurality of Xs may be the same or different, and the group [formula] where R is a methyl group has two A metal salt having the following composition, and (B) a film-forming polymer compound, a monomer thereof, or a mixture thereof, provided that R in the above general formula () is a hydrogen atom. ,z
is 0, the film-forming polymer compound is not polyethylene glycol or polyethylene glycol diglycidyl ether. The film is coated on one or both sides of the film, and then, before completing the crystal orientation, the film is heated to convert the film into a large number of microprotrusions having substantially shape-retentive properties on the film surface. A method for producing an easily slippery biaxially stretched polyester film. 2. The manufacturing method according to claim 1, wherein the metal salt having the composition represented by the above general formula () is water-soluble. 3. The manufacturing method according to claim 1, wherein in the general formula (), Me is a metal in periods 3 to 4 of groups 1 to 4 of the periodic table. 4 In the above general formula (), Me is Mg, Ca,
Claim 1 which is Zn, Al, Ti or Mn
Manufacturing method described in section. 5. The manufacturing method according to claim 1, wherein in the general formula (), R is a hydrogen atom. 6. The manufacturing method according to claim 1, wherein in the general formula (), X is a hydroxyl group or a chlorine atom. 7 As a metal salt having the composition of the above general formula (), the following formula ()-a Here, the definition of R is the same as in the above formula (), X ¹ is the same or different and is a hydroxyl group or a chlorine atom, q is 1 to 4, and r is 2 to 5, provided that q + r = 6 Claim 1 using a metal salt represented by
Manufacturing method described in section. 8 As a metal salt having the composition of the above general formula (), the following formula ()-b Here, Me ¹ is Ca, Mg, Zn, Ti or Mn, and t is equal to the valence of Me ¹ and is a number from 2 to 4.
Manufacturing method described in section. 9. The production method according to claim 1, wherein the film-forming polymer compound is substantially linear water-soluble, water-swellable or water-dispersible. 10 Claim 1 or 9 in which the film-forming polymer compound has an aliphatic hydroxyl group
Manufacturing method described in section. 11. The manufacturing method according to claim 1, which comprises applying the aqueous solution or aqueous dispersion to a uniaxially stretched polyester film. 12. Claim 1 or 11, wherein the aqueous solution or aqueous dispersion is applied using a roll coater on the lower surface of the uniaxially stretched film that is substantially running after leaving the nip roller. Manufacturing method described.