JPH03132345A - Biaxially oriented laminated film - Google Patents

Abstract

PURPOSE:To obtain a biaxially oriented laminated film having good scratch resistance by laminating a thermoplastic resin A film containing inert particles and specific higher aliphatic carboxylic acid to the single surface of a thermoplastic resin B film. CONSTITUTION:A thermoplastic resin A compounded with inert particles and a predetermined amount of at least one of 10 - 33C higher aliphatic monocarboxylic acid and ester, amide or a metal compound thereof is synthesized. This thermoplastic resin A and a thermoplastic resin B are supplied to an extruder for melt lamination to be extruded into a sheet form from the slit like die thereof and the exrudate is cooled and solidified to obtain a non- stretched film. This non-stretched film is biaxially stretched to form a biaxially oriented laminated film wherein the mean particle size of the inert particles is 0.2 - 5 times the A-layer, the content of the inert fine particles in the A-layer is 2 - 20 wt.% and the thickness of the A-layer is 0.1 - 3mum.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a biaxially oriented laminated film.

[Prior Art] Films with improved running properties are known as biaxially oriented laminated films (for example, Japanese Patent Laid-Open No. 1-17655
Publication No. 6, etc.).

[Problems to be Solved by the Invention] However, in the above-mentioned conventional biaxially oriented laminated film,
For example, as process speeds increase in magnetic layer coating for magnetic media applications, calendering processes, or dubbing finished video tapes to produce soft tapes, etc., the surface of the film may be scratched by contacting rolls or guides. It had the disadvantage of being attached. Furthermore, recently, guide pins used in VTR cassettes are often made of plastic, and their slipperiness and resistance to scratches have become issues. It is an object of the present invention to solve such problems and provide a biaxially oriented laminated film that is particularly resistant to scratches (hereinafter referred to as having excellent scratch resistance) when coming into contact with plastic bottles.

[Means for Solving the Problems] The present invention provides a film containing thermoplastic resin B as a main component (B
The main component is a thermoplastic resin A containing inert particles and at least one compound consisting of a higher aliphatic monocarboxylic acid having 10 to 33 carbon atoms, an ester thereof, an amide thereof, or a metal salt thereof, on at least one side of the layer) A biaxially oriented laminated film formed by laminating films (A layer) in which the average particle diameter of the inert particles is 0. 2 to 5 times, the content of the inert particles in the A layer is 2 to 20% by weight, and the thickness of the A layer is 0.01 to 3 μm. .

The thermoplastic resin A constituting the present invention is not particularly limited to polyester, polyolefin, polyamide, polyphenylene sulfide, etc., but polyester, especially ethylene terephthalate, ethylene α, β-bis(2
- Chlorphenoxy)ethane-4,4'-dicarboxylate and ethylene 2,6-naphthalate units are preferably used as the main constituent because the scratch resistance is even better. .

It is extremely desirable that the thermoplastic resin A constituting the present invention be crystalline or optically anisotropic when melted, since the scratch resistance will be even better.

Crystallinity here indicates that it is not so-called amorphous, and quantitatively, the cold crystallization temperature Tcc in the crystallization parameter is detected, and the crystallization parameter ΔT
The cg is 150°C or more. Furthermore, the heat of fusion (change in enthalpy of fusion) measured with a differential scanning calorimeter is 7
．． When the crystallinity is 5 cal/g or more, the scratch resistance becomes even better, which is extremely desirable. In addition,
Two or more types of thermoplastic resins may be mixed or a copolymer may be used within a range that does not interfere with the present invention.

When the thermoplastic resin A constituting the film of the present invention is polyester, the intrinsic viscosity of the film is 0.60 or more, particularly 0.
．． A value of 70 or more is particularly desirable because the scratch resistance becomes even better.

The inert particles in the thermoplastic resin A of the present invention have a relative standard deviation of 0. A value of 6 or less, preferably 0.5 or less is desirable because the scratch resistance becomes even better.

The type of inert particles in the thermoplastic resin A of the present invention is not particularly limited, but in order to satisfy the above preferable particle characteristics, substantially spherical silica particles caused by colloidal silica, particles made of crosslinked polymers (e.g. cross-linked polystyrene)
Alumina silicate, silica in a state where primary particles are aggregated, internally precipitated particles, etc. are not preferred. Especially 10
Scratch resistance is even better in the case of crosslinked polymer particles whose degree of crosslinking is increased until the temperature at weight % weight loss (measured by thermogravimetric analyzer, heating rate 20°C/min, nitrogen atmosphere) is 380°C or higher. This is particularly desirable. Note that in the case of spherical silica derived from colloidal silica, substantially spherical silica with a low sodium content produced by an alkoxide method is particularly desirable because the scratch resistance is even better. However, other particles,
For example, particles of calcium carbonate, titanium dioxide, alumina, etc. can also be used by appropriately controlling the film thickness and average particle size.

The crystallization promotion coefficient of the inert particles in the thermoplastic resin A of the present invention is not particularly limited, but scratch resistance is better when the temperature is -15 to 15°C, preferably -5°C to 10°C. This is particularly desirable.

The size of the inert particles is such that the average particle diameter in the film is 0.0 mm thick of the film (layer A) whose main component is thermoplastic resin A.
2 to 5 times, preferably 0. It needs to be in the range of 5 to 5 times, more preferably 1.1 to 3 times. It is not preferable that the average particle diameter/A layer thickness ratio is smaller than the above range, or conversely, that the ratio is larger than the above range because the scratch resistance becomes poor.

Further, it is preferable that the average particle size of the inert particles is in the range of 0.01 to 0.5 μm1, and more preferably 0.02 to 0.45 μm, because the scratch resistance becomes even better.

The content of inert particles in the thermoplastic resin A of the present invention needs to be 2 to 20% by weight, preferably 3 to 10% by weight, and more preferably 4 to 10% by weight. Even if the content of inert particles is less than the above-mentioned range, it is not preferable that the content is greater than the above range because the scratch resistance becomes poor.

The thermoplastic resin A of the present invention contains 10 to 33 carbon atoms.
At least one compound consisting of a higher aliphatic monocarboxylic acid, its ester, its amide or its metal salt (
(hereinafter referred to as wax).

As the higher aliphatic monocarboxylic acid in the wax consisting of a higher aliphatic monocarboxylic acid having 10 to 33 carbon atoms, its ester, its amide or its metal salt, which is an essential additive component in the thermoplastic resin A of the present invention, ,for example,
Examples include stearic acid, nonadecanoic acid, arachidic acid, carnaubic acid, lignoceric acid, cerotic acid, montanic acid, petroselic acid, oleic acid, erucic acid, linoleic acid, and acid mixtures containing these.
Those of 0 to 33 are preferred.

The higher aliphatic monocarboxylic acid ester in the present invention refers to the above-mentioned higher aliphatic monocarboxylic acid having 2 to 2 carbon atoms.
It is obtained by esterifying part or all of it with a monohydric or dihydric alcohol having 33. Specifically, montanic acid ethylene glycol ester, montanic acid ethyl ester, ceryl montanate, octacosyl lignocerate, mericyl lignocerate, seryl lignocerate, myricyl cerotate, seryl cerotate, etc. are mentioned, and naturally obtained montan wax , carnauba wax, beeswax, candelilla wax, wax wax, prickly wax, and the like are also preferably used.

In the present invention, as for the ester consisting of a higher aliphatic carboxylic acid and an alcohol, the number of carbon atoms of the acid and the alcohol constituting the ester are preferably 18 to 33.
, more preferably a combination of 20 to 32, is particularly desirable since it provides particularly good scratch resistance.

Examples of higher aliphatic monocarboxylic acid amides in the present invention include amides of the above-mentioned higher aliphatic monocarboxylic acids, such as stearic acid amide, oleic acid amide, erucic acid amide,
Examples include behenic acid amide, and erucic acid amide is particularly preferred.

Examples of metal salts of higher aliphatic monocarboxylic acids in the present invention include alkali and/or alkaline earth metal salts of the above-mentioned higher aliphatic monocarboxylic acids, such as lithium, sodium, potassium, barium, magnesium, calcium, and strontium. Particularly preferred compounds include magnesium stearate, calcium montanate, sodium montanate, and sodium erucate.

The main component of the wax in the present invention, ie, 50% by weight or more, is the above-mentioned higher aliphatic monocarboxylic acid or a derivative thereof.

If the number of carbon atoms in the aliphatic monocarboxylic acid moiety of the main component of these waxes is less than 10, it will bleed out to the film surface severely and cause poor calendar staining, while if it exceeds 33, the scratch resistance will be poor. So I don't like it. Wax content is thermoplastic resin A10
It is preferably 0.005 to 2 parts by weight, more preferably 0.01 to 1 part by weight, even more preferably 0.05 to 0.5 parts by weight. It is not preferable that the above content is less than 0.005 parts by weight, or conversely, if it exceeds 2 parts by weight, the scratch resistance will be poor.

In the present invention, when the A layer containing the above-mentioned specific wax has a specific particle size/A layer thickness ratio and content, and A layer thickness, the synergistic effect provides remarkable scratch resistance and resistance. This provides dubbing properties.

Although the surface particle concentration ratio of at least the surface of layer A of the present invention is not particularly limited, it is particularly desirable that it is 1/10 or less, particularly 1150 or less, since the scrubbing and sowing resistance will be even better.

In terms of scratch resistance, the film of the present invention has at least the A layer at a depth of 3.5 mm from the surface. In the concentration distribution of inert particles measured up to OOOnm, the depth (distance from the surface) where the particle concentration is 10 times the surface particle concentration a (nm
) and the depth b (nm
) (baa) preferably satisfies the following formulas (i) and (ii).

10≦b-a≦1500 --- (i) 5≦a
≦500 (ii) The thermoplastic resin A of the present invention usually contains organic additives such as antioxidants, heat stabilizers, lubricants, and ultraviolet absorbers within the range that does not impede the purpose of the present invention. It may be added to the extent that it is added.

The film of the present invention is a film in which the above composition is biaxially oriented. - Axial or non-oriented films are not preferred because they have poor scratch resistance. The degree of this orientation is not particularly limited, but the Young's modulus, which is a guideline for the degree of molecular orientation of polymers, is 350 kg/m in both the longitudinal and width directions.
If it is m2 or more, the scratch resistance will be even better, so it is extremely desirable. The upper limit of Young's modulus, which is a measure of the degree of molecular orientation, is not particularly limited, but is usually 1500.
The manufacturing limit is around kg/mm2.

Furthermore, even if the Young's modulus of the film of the present invention is within the above range, a portion of the thickness and direction of the film, for example, the orientation of the polymer molecules near the surface layer is non-oriented or -axially oriented. That is, it is particularly preferable that the molecular orientation in the entire thickness direction is biaxial because the scratch resistance becomes even better. In particular, when the molecular orientation measured by Atsube refractometer, laser refractometer, total internal reflection laser Raman method, etc. is biaxially oriented on both the front and back surfaces, the scratch resistance becomes even better. desirable.

Further, the thermoplastic resin A is a crystalline polyester, and the total reflection Raman crystallization index of the surface thereof is 20 cm-' or less,
Preferably, the thickness is 18 cm-' or less, and more preferably 17 cm-' or less, since the scratch resistance becomes even better.

The thickness of layer A of the present invention is 0.01 to 3 μm, preferably 0.
．． 02~1μm1 More preferably 0°03~0.5μm
It is necessary that m. It is not preferable if the thickness of layer A is smaller than the above range, or conversely, if it is larger than the above range, the scratch resistance will be poor.

The average protrusion height on the surface of at least A layer of the present invention is 5 to 5o.
onm, preferably 10 to 300 nm.

More preferably, the range of 15 to 200 nm is particularly desirable because the scratch resistance becomes even better. The average distance between protrusions on the surface of at least layer A of the present invention is 6 μm
Hereinafter, it is particularly preferable that the thickness is 4 μm or less because the scratch resistance becomes even better.

In terms of scratch resistance, the film of the present invention desirably has a surface roughness parameter Rt/Ra of at least one side of 8.0 or less, particularly 7.5 or less.

In terms of scratch resistance, the film of the present invention desirably has a surface roughness parameter Rx/R1 of at least one side of 0.85 or more and an Sm of 6.0 μm or less.

The lamination combination of the laminated film of the present invention is not particularly limited, but A/B, A/B/A, A/B/C, etc. are preferably used. Here, it is desirable to use thermoplastic resins B and C that are desirably used for thermoplastic resin A. Furthermore, the thermoplastic resins A, B, and C may be the same type or different types.

It is not particularly necessary to contain inert particles in the film (layer B) mainly composed of thermoplastic resin B of the present invention, but
Average particle size is 0.01 to 2 μm, especially 0.02 to 0.45
It is extremely desirable to contain 0.001 to 0.15% by weight, particularly 0.005 to 0.05% by weight, of inert particles having a diameter of .mu.m, since this further improves the scratch resistance.

The type of inert particles contained in thermoplastic resins B and C is A
It is desirable to use what is desirable for the layer. The types and sizes of particles contained in layer A, layer B, and layer C may be the same or different.

The film of the present invention is a laminated film made of the above composition. Ordinary single-layer films are not preferred because they not only do not have satisfactory scratch resistance, but also suffer from calender scraping during the above-mentioned processing steps.

Next, a method for producing the film of the present invention will be explained.

First, as a method for incorporating inert particles into a thermoplastic resin, when the thermoplastic resin is polyester, ethylene glycol, which is a diol component, is dispersed in the form of a slurry, and this ethylene glycol is mixed with a predetermined dicarboxylic acid. Polymerization with other components is effective in obtaining a film having the relationship between film thickness and average particle size, content within the range of the present invention, and orientation state within the desired range. In addition, a method of controlling the melt viscosity, copolymerization components, etc. of polyester containing inert particles to keep its crystallization parameter ΔTcg in the range of 40 to 65°C is based on the film thickness and average particle size within the range of the present invention. It is effective to obtain a film having a desired relationship, content, and orientation state within a desired range.

Additionally, a slurry of ethylene glycol of inert particles was added to
The method of heat treatment at a temperature of 40 to 200°C, especially 180 to 200°C for 30 minutes to 5 hours, especially 1 to 3 hours, is based on the relationship between the film thickness and average particle size within the range of the present invention, the content, the orientation state in the desired range, This is effective in obtaining a film with a surface layer particle concentration ratio.

Another method for incorporating inert particles into a thermoplastic resin is to prepare particles in ethylene glycol at a concentration of 140 to 200%.
℃, especially at a temperature of 180 to 200℃ for 30 minutes to 5 hours, especially 1 to 3 hours, and then mixed with a thermoplastic resin in the form of a slurry in which the solvent has been replaced with water, and then mixed with a thermoplastic resin in a vent type twin screw extrusion machine. The method of kneading and kneading into a thermoplastic resin also has the following characteristics: the relationship between film thickness and average particle diameter within the range of the present invention, the content, the orientation state within the desired range, the surface layer particle concentration ratio, and the average protrusion height. It is extremely effective.

A method for adjusting the particle content is to prepare a high-concentration master using the above method, and then dilute it with a thermoplastic resin that does not substantially contain inert particles during film formation to adjust the particle content. The method is valid.

Next, as a method for laminating a film mainly composed of thermoplastic resin A on at least one side of a film mainly composed of thermoplastic resin B, the following method is effective.

Thermoplastic resin A and thermoplastic resin B containing a predetermined amount of inert particles and wax are dried as necessary, and then supplied to a known extruder for melt lamination and extruded into a sheet from a slit-shaped die. It is cooled and solidified on a casting roll to form an unstretched film. That is, the thermoplastic resin A1B is laminated using two or three extruders, a two or three layer manifold or a merging block, two or three layers of sheets are extruded from the die, cooled with a casting roll, and unstretched. make a film. In this case, the method of installing a static mixer and a gear pump in the polymer flow path of thermoplastic resin A is based on the relationship between the film thickness and average particle size within the range of the present invention, the content, the orientation state in the desired range, the average protrusion height, the surface layer It is effective in obtaining a film with a particle concentration ratio. In addition, it is recommended that the melting temperature of the extruder on the thermoplastic resin A side be 10 to 40°C higher than that on the thermoplastic resin B side to maintain the relationship between the film thickness and average particle size within the range of the present invention, the content, and the desired range. It is effective in obtaining a film with good orientation, average protrusion height, surface particle concentration ratio, and total reflection Raman crystallization index.

Next, this unstretched film is biaxially stretched and biaxially oriented. As the stretching method, a sequential biaxial stretching method or a simultaneous biaxial stretching method can be used. However, by using a sequential biaxial stretching method that first stretches in the longitudinal direction and then in the width direction, the longitudinal stretching is divided into three or more stages, and the total longitudinal stretching ratio is 3.
The method carried out at a magnification of ~9 times is effective for obtaining a film having the relationship between film thickness and average particle diameter, content, orientation state and surface layer particle concentration ratio within the desired range of the present invention. However, when the thermoplastic resin is a molten optically anisotropic resin, a longitudinal stretching ratio of 1.0 to 1.1 times is appropriate. The longitudinal stretching temperature varies depending on the type of thermoplastic resin and cannot be generalized, but usually the first stage is 50 to 130°C, and the second stage is 50 to 130°C.
It is effective to make the thickness higher than that in the subsequent stages to obtain a film having the relationship between film thickness and average particle diameter, content, orientation state, average protrusion height, and surface layer particle concentration ratio within the desired range of the present invention. . However, in this case, the stretching temperature must be set based on thermoplastic resin B. Moreover, the longitudinal direction stretching speed is preferably in the range of 5,000 to 50,000%/min. A common method for stretching in the width direction is to use a stick.

The stretching ratio is 3 to 5 times, and the stretching speed is 1,000 to 20.
000%/min and the temperature is preferably in the range of 80 to 160°C. Next, this stretched film is heat treated. The heat treatment temperature in this case is 170-200°C1, especially 170-190°C
, the time is preferably in the range of 0.5 to 60 seconds, but in the heat treatment process of the two-layer laminated film, the temperature of the hot air blown onto the thermoplastic resin A layer is 3 to 20 ° C lower than that of the thermoplastic resin B and 1. This is particularly effective for obtaining a film with the relationship between film thickness and average grain size, content, orientation state within the desired range, average protrusion height, surface layer particle concentration ratio, and total reflection Raman crystallization index within the range of the present invention. be.

[Method for Measuring Physical Properties and Evaluating Effects j The method for measuring characteristic values and evaluating the effects of the present invention are as follows.

(1) Average particle size of particles Polyester is removed from the film by plasma low-temperature ashing treatment to expose particles. The processing conditions are selected so that the polyester is incinerated but the particles are not damaged.

This is observed with a scanning electron microscope (SEM), and the image of the particles is processed with an image analyzer. The following numerical processing is performed when the number of particles is 5000 or more while changing the observation location, and the number average diameter obtained thereby is taken as the average particle diameter.

D=ΣD, /N Here, D is the equivalent circle diameter of the particles, and N is the number of particles.

(2) Relative standard deviation of particle size Standard deviation σ(=(Σ(D+
D)' /N)1/2) divided by the average diameter (
It was expressed as σ/D).

(3) Particle content A solvent is selected that dissolves the polyester but does not dissolve the particles, centrifuges the particles from the polyester, and defines the particle content as the ratio (weight %) to the total weight of the particles. In some cases, infrared spectroscopy may also be effective.

(4) Crystallization parameter ΔT c g, heat of fusion was measured using a differential scanning calorimeter (D SC).

The DSC measurement conditions are as follows. That is, sample 1
0111g was set in a DSC device, melted at a temperature of 300°C for 5 minutes, and then rapidly cooled in liquid nitrogen.

This rapidly cooled sample was heated at a rate of 10°C/min, and the glass transition point Tg
Detect. The temperature was further increased, and the exothermic peak temperature of crystallization from the glass state was defined as the cold crystallization temperature Tcc.

The temperature was further increased, and the heat of fusion was determined from the melting peak. Here, the difference between Tcc and Tg (Tea-Tg) is defined as a crystallization parameter ΔTcg.

(5) Crystallization acceleration coefficient Measure ΔTcg (I) of a polyester containing 1% by weight of particles by the method described in (4) above, and ΔTcg (n) of a polyester of the same viscosity from which particles have been removed.
The difference between g(II) and ΔTcg (I) [ΔTcg(n)−
ΔTcg(I)] was taken as the crystallization promotion coefficient.

(6) Young's modulus 2 using an Instron type tensile tester according to the method specified in J I 5-Z-1702.
Measurement was performed at 5° C. and 65% RH.

(7) Surface molecular orientation (refractive index) Measured using an Atsube refractometer using sodium D line (589 nm) as a light source. Methylene iodide was used as the mounting solution, and the measurement was performed at 25° C. and 65% RH. The biaxial orientation of the polymer has a refractive index of N in the longitudinal direction, width direction, and thickness direction.
, , N2, N3, the absolute value of (N, -N2) is 0.07 or less, and N3 / [(N, +N2 ) /
2] is 0.95 or less. Alternatively, the refractive index may be measured using a laser refractometer. Furthermore, if measurement is difficult with this method, total internal reflection laser Raman method can also be used.

Total reflection laser Raman measurement involves measuring the total reflection Raman spectrum. For example, in the case of polyethylene terephthalate (hereinafter abbreviated as PET), 1615 Cm-' (skeletal vibration of benzene ring) and 1730 cm-' (stretching vibration of carbonyl group) are measured. ) Polarization measurement ratio of band intensity ratio (YY/X
X ratio etc. Here, YY: Set the polarization direction of the laser to Y,
This method utilizes the fact that the detection of man light parallel to Y (XX: detection of man light parallel to X when the polarization direction of the laser is set to X) corresponds to the molecular orientation. The biaxial orientation of a polymer can be determined by converting the parameters obtained from Raman measurement into refractive indices in the longitudinal direction and width direction, and based on their absolute values, differences, etc. The measurement conditions in this case are as follows.

■Light source Argon ion laser (5145A) ■Setting the sample The surface of the film is pressed against a total reflection prism, and the incident angle of the laser to the prism (angle with the film thickness direction) is 60°.
°.

■Detector PM: RCA31034/Photon C
own system (llsma+utsa
C1230) (supp1716QOV) ■Measurement conditions 5LIT 1000μm LASER] 0
0mW GATE TIME 1.0secSCAN 5
PEED 12cn+-'/minSAMPL
ING INTERVAL O, 2cm -'REPE
AT TIME 6 (8) Total reflection Raman crystallization index The total reflection Raman spectrum was measured, and the half width of 1730 cm-1, which is the stretching vibration of the carbonyl group, was taken as the total reflection Raman crystallization index of the surface. Measurement conditions are as above (7)
It is similar to The measurement depth is 500 to 1,000 mm from the surface.
Approximately 0 people.

(9) Intrinsic viscosity [η] (unit: d!/g) A value calculated from the following formula from the solution viscosity measured at 25° C. in orthochlorophenol is used. That is, η,,/C= [η]+K[η]2 ・With a smile, η5p
= (solution viscosity/solvent viscosity) -1, C is the weight of dissolved polymer per 100ml of solvent (g/100ml, usually 1.2)
, K is the Huggins constant (C, 343). In addition, solution viscosity and solvent viscosity were measured using an Ostwald viscometer.

(10) Surface layer particle concentration, surface layer particle concentration ratio The secondary ion mass spectrum (S IMS) was determined by J”11J,s, and the concentration of the element with the highest concentration among the elements caused by particles in the film and the carbon element in the polyester The particle concentration is defined as the particle concentration, and analysis is performed in the thickness direction.Particle concentration A (defined as surface layer particle concentration) at the outermost layer particle concentration (point of depth O) measured by SMS and further analysis in the depth direction A/B, the ratio of the maximum concentration B obtained by continuously obtaining , was defined as the surface layer particle concentration ratio.

The measuring device and conditions are as follows.

Primary ion species: 02 Primary ion acceleration voltage: 12KV Primary ion current: 200nA Raster area: 400μm Mouth analysis area: Gate 30% Measurement vacuum level: 6. OX 10-9 Tor
rE-GUN: 0.5KV-3,0A (11
) Average height of surface protrusions, number of protrusions, average protrusion spacing Using a two-detector force type scanning electron microscope, image processing is performed on the measured values of protrusion height when scanning with the height of the flat surface of the film surface as 0. and reconstruct the film surface protrusion image on the image processing device.

Next, the highest value among the binarized individual protrusion portions is determined as the height of the protrusion, and this value is determined for each protrusion. This measurement was repeated 500 times at different locations to determine the number of protrusions, and the average height of all the measured protrusions was taken as the average height. The magnification of a scanning electron microscope is 1,000
Choose a value between ~8.000x. The average distance between protrusions was determined from the number of protrusions.

In addition, in some cases, a high-precision optical interference type three-dimensional surface analysis device (TOPO-3D manufactured by WYKO, objective lens = 40~
200 times) may be read and used as the above-mentioned SEM value.

(12) Surface roughness parameter Ra (center line average roughness),
Rt (maximum height), Rz (10 point average roughness), Sm (protrusion spacing), and Rp (center line depth) were measured using a surface roughness meter. The conditions were as follows, and the average value of 20 measurements was taken as the value.

・Stylus tip radius = 0.5μm ・Stylus load: 5mg ・Measurement length: 1mm ・Cutoff value: 0.08mm (13) Tape made by slitting a scratch-resistant film into a 1/2 inch wide tape. Using a runability tester, run on a plastic guide pin (running speed 1゜000m/min)
, number of trips IQpass, wrapping is Kakuji 60, running tension crab 65g). At this time, the scratches in the film were observed under a microscope, and less than 2 scratches with a width of 2.5 μm or more per tape width were determined to be good, 2 or more and less than 10 scratches were determined to be good, and 10 or more scratches were determined to be poor. Excellent is desirable, but good is still usable for practical purposes.

(14) Calendar stain Test the film coated with the magnetic layer using a small calender device (steel roll/nylon roll, 5-stage type, nylon roll in contact with the base film) 70°C, linear pressure 200
Calendar in kg/cm. 7000 times the above processing
After continuing for 0 m, white powder generated by the Kono treatment and attached to the nylon roll is observed and ranked as follows.

Rank C: Almost no white powder is attached.

Rank B: A slight amount of white powder adheres, but it does not cause problems in the processing process or product performance.

Rank C: There is a lot of white powder adhesion, which causes problems in the processing process and product performance, so it cannot be used.

Ranks A and B are ○, rank C is ×.

[Example] The present invention will be explained based on examples.

Examples 1 to 4, Comparative Examples 1 to 4 Ethylene glycol slurry containing crosslinked polystyrene particles with different average particle sizes and silica particles derived from colloidal silica was prepared, and after heat treatment at 190 ° C. for 1.5 hours. , polycondensed after transesterification with dimethyl terephthalate and containing 1.0 to 15% by weight of the particles.
I made ET pellets. At this time, the polycondensation time was adjusted so that the intrinsic viscosity was 0.70. A predetermined amount of master polymer containing various waxes was mixed with this (thermoplastic resin A
). Further, PET having an intrinsic viscosity of 0.62 and containing substantially no inert particles was produced by a conventional method, and was designated as thermoplastic resin B. Each of these polymers was dried under reduced pressure (3 Torr) at 180° C. for 3 hours.

Thermoplastic resin A was supplied to extruder 1 and melted at 310°C,
Furthermore, thermoplastic resin B is supplied to extruder 2, melted at 280°C, these polymers are merged and laminated in a merged block (feed block), and cast with a surface temperature of 30°C using an electrostatic casting method. It was wound around a drum and cooled and solidified to produce an unstretched film with a two-layer structure. At this time, an unstretched film was prepared with a ratio of die slit gap/unstretched film thickness of 10. In addition, the total thickness and the thickness of the thermoplastic resin A layer were adjusted by adjusting the discharge amount of each extruder. This unstretched film was stretched 4.5 times in the longitudinal direction at a temperature of 80°C. This stretching was carried out in four stages with a difference in peripheral speed between two sets of rolls.

This -axially stretched film was stretched using a stenter at a stretching speed of 2.
Stretched 4.0 times in the width direction at 00096/min at 100°C, heat treated at 200°C for 5 seconds under constant length, to a total thickness of 15
A biaxially oriented laminated film having a thickness of 0.05 to 5 μm for thermoplastic resin A layer was obtained. The parameters of the present invention for these films are as shown in Table 1. When the parameters of the present invention were within the range, the scratch resistance was excellent as shown in Table 1, but otherwise. A film satisfying scratch resistance was not obtained.

Claims (5)

[Claims] (1) Film whose main component is thermoplastic resin B (B layer)
on at least one side of the inert particles and 10 carbon atoms.
A biaxially oriented film formed by laminating a film (A layer) whose main component is a thermoplastic resin A containing at least one of compounds consisting of ~33 higher aliphatic monocarboxylic acids, their esters, their amides, or their metal salts. A laminated film, wherein the average particle size of the inert particles is 0.2 to 5 times that of layer A, the content of the inert particles in layer A is 2 to 20% by weight, and
A biaxially oriented laminated film characterized in that the layer thickness is 0.01 to 3 μm. (2) The biaxially oriented laminated film according to claim (1), wherein the A layer is provided only on one side of the B layer. (3) The biaxially oriented laminated film according to claim (1), wherein the A layer is provided on both sides of the B layer. (4) A film containing the A layer on one side of the B layer and a thermoplastic resin C containing inert particles on the opposite side (
The biaxially oriented laminated film according to claim 1, further comprising a layer C). (5) The biaxially oriented laminated film according to any one of claims (1) to (4), wherein the B layer has an average particle size of 0.01 to
A biaxially oriented laminated film containing 0.001 to 0.15% by weight of inert particles of 2 μm.