JPH0390329A - Biaxially oriented thermoplastic resin film - Google Patents

Abstract

PURPOSE:To make the density of particle protrusions high and the height of said protrusions uniform by forming inert particles having a predetermined diameter and inert particles being cohering particles in which many primary particles whose diameter is smaller than the average diameter of said inert particles having a predetermined diameter are linked without having directional properties. CONSTITUTION:A thermoplastic resin A and a film mainly composed of inert particles A, B are co-extruded and laminated on at least one surface of a film mainly composed of a thermoplastic resin B in a thickness of not less than 0.01mum to form a biaxially oriented thermoplastic resin film. The average diameter of the inert particles A is 0.1 to 10 times the thickness of the film layer of said thermoplastic resin A, and the inert particles B are constituted of cohering particles in which many primary particles whose average diameter is smaller than that of the inert particles A are linked without having directional properties. The shape of the inert particles A is not restricted especially; however, particles whose diametral ratio in the film is 1.0 to 1.3, and especially, spherical particles are preferable because such particles allow the surface of the film to be hardly flawed and make abrasion resistance better.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a biaxially oriented thermoplastic resin film, and particularly to a biaxially oriented thermoplastic resin film having a laminated film structure and having improved surface properties.

[Prior art] Biaxially oriented thermoplastic/[4@fat film with improved surface properties] A film in which substantially spherical silica particles derived from colloidal silica are contained in polyester, which is a thermoplastic resin. For example, it is known that
-171623 Publication>.

In such a biaxially oriented thermoplastic resin film,
The contained silica particles can form protrusions on the film surface, lowering the coefficient of friction on the surface and improving handling and running properties.

[Problems to be Solved by the Invention] However, in the conventional biaxially oriented thermoplastic resin film described in J-1, the PJ-containing silica particles are distributed approximately randomly throughout the thickness direction of the film. There is a limit to the increase in the density of protrusions due to the particles contained therein, and the height of the protrusions also varies considerably at random. On the film surface where the L-shaped protrusions are H, the tip surfaces of the protrusions mainly come into contact with the other object (for example, a roll in the processing process), but if the protrusion density is low, the contact area by the tip surfaces becomes small. C
Since the contact surface pressure becomes high, a problem arises in the abrasion resistance of the film surface, and there is a possibility that the film surface becomes easily scraped. In addition, if the height of the protrusions on the film surface is uneven, the high protrusions may be scraped or damaged, resulting in film processing]
Processes, such as printing in packaging applications]: magnetic layer coating/calendering in magnetic recording media applications, or thermal transfer applications in thermal transfer applications. There is a risk of scratches.

In view of the above-mentioned problems, the present invention aims to achieve high density of protrusions and uniform protrusion height when forming protrusions on the surface of a biaxially oriented thermoplastic resin film using contained particles. A further object of the present invention is to make the surface of the film on which the protrusions are formed even more resistant to scraping and damage.

[Means for Solving the Problems] The biaxially oriented thermoplastic resin film of the present invention that meets this objective is produced by coextruding a film containing thermoplastic resin A and inert particles A and B as main components. A two-fold oriented thermoplastic resin film comprising a thin layer of 0.01 μm or more thick on at least one side of a film containing B as a main component,
The average particle size of the inert particles A is 0.1 to 10 times the film layer thickness of the thermoplastic resin A, and the inert particles B have an average particle size larger than the average particle size of the inert particles A. It consists of agglomerated particles in which many small primary particles are connected without directionality.

The thermoplastic resin A constituting the present invention is not particularly limited to polyester, polyolefin, polyamide, polyphenylene sulfide, etc., but in particular, polyester, polyphenylene sulfide, etc.
Among them, the main constituent is at least one structural unit selected from ethylene terephthalate, 1-tylene α, β-bis(2-chlorophenoxy>ethane-4,4′-dicarboxylate), and ethylene 2,6-naphthalate units. It is desirable that the thermoplastic resin constituting the present invention has better abrasion resistance and scratch resistance (also referred to as scratch resistance) when it is crystalline. Crystallinity here means that it is not so-called amorphous, and quantitatively, a cold crystallization temperature of 11tTcc is detected in the crystallization parameter, and crystallinity is extremely desirable. The temperature change parameter ΔTCg is 150°C or less.Furthermore,
It is extremely desirable that the heat of fusion (enthalpy of fusion change) measured by differential scanning calorimetry exhibits crystallinity of 7.5 cal/g or more, as this will further improve the abrasion resistance and scratch resistance. It is particularly preferable to use polyester as a main component because it has even better abrasion resistance and scratch resistance.It should be noted that two or more thermoplastic resins may be mixed as long as the present invention is not impaired. Alternatively, a copolymer may be used.

The shape of the inert particles A in the thermoplastic resin A of the present invention is not particularly limited, but particles having a particle size ratio (longer diameter/breadth diameter of particles) in the film of 1.0 to 1.3, particularly, Spherical particles are desirable because the film surface is less likely to be damaged and the abrasion resistance is even better.

In addition, for inert particles, the single particle index in the film is 0.
．． A value of 7 or more, preferably 0.9 or more is particularly desirable because scratch resistance and abrasion resistance become better all around.

The type of inert particles A used in the present invention is not particularly limited, but in order to satisfy the above preferable particle characteristics, alumina silicate, silica in a state where primary particles are aggregated, internally precipitated particles, etc. are not preferable. . Preferred particles include substantially spherical silica particles derived from colloidal silica, particles made of crosslinked polymers (for example, crosslinked polystyrene), and in particular, at a temperature at 10 wt. Measured using Shimadzu TG-30M. Heating rate 2
It is particularly desirable to use crosslinked polymer particles whose degree of crosslinking is increased to a temperature of 380°C or higher (0°C/min) because the scratch resistance and abrasion resistance will be even better. In addition, in the case of spherical silica derived from colloidal silica, scratch resistance and abrasion resistance are particularly good in the case of substantially spherical silica with low sodium content manufactured by an alkoxide method. desirable. However, other particles, such as particles of calcium carbonate, titanium dioxide, alumina, etc., can also be used satisfactorily with proper control of film thickness and average particle size.

The size of the inert particles is such that the average particle diameter in the laminated film containing the inert particles is 0.1 of the thickness of the laminated film.
The range is 10 times to 10 times, preferably 0.5 to 5 times, more preferably 1.1 to 3 times. The thickness of the laminated film layer is 0.01 μm or more. When it is thinner than this, the film layer tends to be easily inter-walled, resulting in poor scratch resistance. Furthermore, if the ratio between the average particle diameter of the inert particles A and the thickness of the laminated film is smaller than the above range, the effect of forming surface protrusions by the inert particles A will be reduced, and at the same time the height of the protrusions will become non-uniform. , scratch resistance and abrasion resistance are poor, and on the other hand, even if it is large, the shape! This is not preferable because the protrusions that are cut out are likely to be destroyed, resulting in poor scratch resistance and abrasion resistance.

In addition, the average particle size (diameter) of the inert particles A in the thermoplastic resin A in the film is basically larger than the average particle size of the primary particles of the small active particles B described later. is 0.007 to 0.5μ, preferably 0.02 to 0
．． A thickness in the range of 45 μm is desirable because scratch resistance and abrasion resistance become even better.

That is, the laminated film layer t) according to the present invention contains inert particles A having an average particle diameter near or larger than the thickness of the film. In other words, the ultrathin laminated film contains minute inert particles A having an average particle diameter near or larger than the thickness of the film. therefore,
The inert particles A can be distributed in the thickness direction of the biaxially oriented thermoplastic resin film body, concentrating substantially only in the area of the laminated film. As a result, the particle density in the laminated film can be easily increased, and the density of the protrusions on the film surface formed by the particles can also be easily increased. Furthermore, by being contained in the laminated film, the inert particles A are regulated in the thickness direction of the biaxially oriented thermoplastic resin film body, and the thickness of the laminated film is Since the above-mentioned relationship exists between the particle diameter and the average particle diameter, the height of the surface protrusions formed by the particles becomes extremely uniform.

In the film diagram of this thermoplastic resin A, inert particles B are further contained.

The inert particles B basically have an average particle size of the secondary particles that is much smaller than the average particle size of the inert particles A, and have a large number of secondary particles without directionality. It is contained in the film in the form of bead-like or network-like agglomerated particles. The average particle size of the primary particles of the inert particles B is in the range of 5 to 1100n as described above.
This is preferable for forming forest-like or network-like agglomerated particles.

The inert particles B made of such aggregated particles extend continuously in large numbers around the small active particles A, thereby increasing the retention strength of the inert particles within the laminated film, and also increasing the strength of the laminated film itself. Reinforce. That is, the inert particles A are mainly responsible for forming protrusions on the film surface, and the inert particles B are responsible for the retention strength of the inert particles and for reinforcing the laminated film base. As a result, the surface protrusions formed with uniform height and high density by incorporating the inert particles A into the ultra-thin laminated film as described above become more difficult to scrape due to the presence of the inert particles B. The abrasion resistance and scratch resistance of the film surface are improved.

The type of inert particles B is not particularly limited as long as it forms beaded or network-like aggregated particles as described above, but preferable examples include δ-alumina, γ-alumina, beaded silica, and network dioxide. One example is titanium.

The content of inert particles B in the laminated film is 0.
A small amount of 0.05 to 1% is sufficient. If the amount is less than this, the above-mentioned reinforcing effect cannot be expected, and if it is more than this, the laminated film layer will become brittle due to the large amount of fine particles contained.
There is a risk that it will be easily scratched.

A film containing inert particles A and B as main components is laminated onto such a thermoplastic resin on at least one side of the film containing thermoplastic resin B as a main component.

Thermoplastic resin B is made of the same material as thermoplastic resin A in the previous book, and thermoplastic resin B and thermo-aT plastic resin A may be of the same type or different.

The film layer made of thermoplastic resin is laminated on both sides or one side of the film layer made of thermoplastic resin B. In other words,
This is a case where the laminated structure is A/B/A1A/B, but of course it may be A/B/C in which a 0 layer with a different surface state from A is provided on the opposite side of A, or it may be a multilayer structure with more than that. , (Here, the types of thermoplastic resins A, B, and C may be the same or different types. Also, at least one surface needs to be the A layer.) As the thermoplastic resin B, Crystalline polymers are desirable. Specific examples include polyester, polyamide, polyphenylene sulfide, and polyolefin, but polyester is particularly desirable because it has better scratch resistance and abrasion resistance. , ethylene terephthalate, ethylene α, β-bis(
It is desirable to have at least one type of structural unit selected from 2-chlorophenoxy)ethane-4,4-dicarboxylate and ethylene 2,6-naphthalate units as the main constituent because the scratch resistance is particularly good.

However, other components may be copolymerized within a range that does not impede the present invention, within a range that does not impair desirable crystallinity, and preferably within 5 mol%.

The thermoplastic resin B of the present invention may also be blended with other types of polymers within the range that does not impede the purpose of the present invention, and organic additives such as antioxidants, heat stabilizers, lubricants, and ultraviolet absorbers may be added. The agent may be added to the extent that it is normally added.

There is no particular need to contain inert particles in the film mainly composed of thermoplastic resin B, but if this film forms one surface of the film, the average particle size is 0.000.
7-2 t17n, especially 0.02-0.45 u rr
t inert↑1 particle is 0.001 to 0.2% by weight, especially 0
．． 005 to 0.15% by weight, and 0.005 to 0.00% by weight.
When the content is 12% by weight, the friction coefficient and scratch resistance are improved. This is extremely desirable because it not only provides a good J but also a good film winding appearance. As for the type of inert particles contained, it is desirable to use those preferably used as inert particles contained in the thermoplastic resin A. The types and sizes of particles contained in thermoplastic resins A and B may be the same or different.

Thermoplastic resin A containing inert particles A and B as described above
and thermoplastic resin B are laminated by coextrusion, formed into a sheet, and then stretched into two wheels to form a -axis oriented thermoplastic resin film. Lamination by coextrusion in the present invention refers to thermoplastic resin A containing inert particles A and B,
Thermoplastic resin B is extruded using different extrusion devices,
This refers to stacking the decoy sheets before discharging them from the nozzle. This lamination may be carried out in the nozzle (for example, a manifold) for forming and discharging into a sheet, but as mentioned above, since the laminated film layer is extremely thin, it is carried out within the polymer tube before introducing it into the nozzle. It is preferable. In particular, it is particularly preferable to form the laminated portion within the polymer tube into a rectangular shape, since this allows uniform lamination in the width direction and facilitates subsequent biaxial stretching. The molten polymer laminated in the rectangular lamination section in the polymer tube is expanded to a predetermined width in the sheet width direction in the manifold in the die, discharged from the die in the form of a sheet, and then stretched into two wheels. Therefore, even if the laminated film layer after two-wheel orientation is extremely thin, the inert particle-containing thermoplastic resin polymer will be laminated to a considerable thickness in the rectangular laminated section inside the polymer tube, making it easy to Can be laminated with high precision.

The thermoplastic resin film of the present invention oriented in two wheels preferably has a Young's modulus of 4008 g/mrrt" or more in the width direction, and more preferably has a Young's modulus of 400 in both the width and length directions for videotape applications. /(!i
It is preferable that F/a2 or more. By laminating the above-mentioned rectangular stacked portions in a J #i polymer tube, uniform lamination is possible, and even if the laminated film layer is an a-layer, at least 3 times the width direction stretching ratio can be obtained. Therefore, the Young's modulus in the width direction of 400 Ky/M2 or more can be easily achieved.

If the Young's modulus is lower than the above value, when a wide film is slit into a narrow width according to the intended use, the properties of powder falling from the edge of the slit film will be poor, and the generated film powder may cause various problems. Because of this, I don't like it. In addition, the Young's modulus in the width direction and longitudinal direction is above fl
If it is lower than i, the dubbing resistance as a videotape is
This is not preferable because there is a risk that the dropout characteristics will deteriorate.

Further, in the biaxially oriented thermoplastic resin film of the present invention, it is preferable that the particle concentration ratio of the inert particles A in the surface layer on the side of the laminated film containing the inert particles A and B is 0°1 or less. This surface layer particle concentration ratio is shown in the measurement method described below.
This shows how the inert particles forming the film surface protrusions are covered with a thin film of thermoplastic resin on the film surface, and the degree to which the particles are substantially directly exposed to the film surface is high. Although the culm surface layer particle concentration ratio is high and surface protrusions are formed, the higher the degree to which the culm is covered with a thin film of thermopJ plastic resin, the lower the surface layer particle concentration ratio is. In the present invention, inert particles A mainly form protrusions on the film surface, but because the inert particles A are covered with a thin film of thermoplastic resin A due to the effect of rectangular lamination, the inert particles A are Even if the particles are distributed at high density in the ultra-thin laminated film layer, the particles are firmly held in the laminated film layer and, ultimately, in the base film layer of thermoplastic resin B. Therefore, by setting the surface layer particle concentration ratio to the above value or more, drop-off of particles, etc. is prevented, and the scratch resistance and abrasion resistance of the film surface are maintained high. Such a surface particle flU ratio can be achieved by laminating by coextrusion. Incidentally, it is possible to use a coating method to create a film similar to the present invention, that is, to coat a base film layer with an extremely thin resin layer and to contain inert particles within the resin layer. □□ The particle 11 degree ratio is significantly higher (that is, the degree to which the particles are substantially directly exposed to the surface is significantly higher), resulting in an extremely brittle surface compared to the film of the present invention.

In the film of the present invention, the height of the surface protrusions formed by the inert particles A is not particularly limited, but in order to obtain the desired effect of improving slipperiness (reducing the coefficient of friction), the average height of the protrusions must be The height is 0.3 of the average particle size to inert particles
It is preferable to set the average particle diameter of the inert particles and the thickness of the laminated film of the thermoplastic resin A so that the average particle size of the inert particles is at least twice as large. Further, in order to obtain uniform and high-density protrusions, it is preferable that the standard deviation of the particle size distribution of the inert particles A themselves is 0.5 or less.

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

First, the inert particles A and B can be incorporated into the thermoplastic resin A after, during, or before polymerization. , B are mixed in at the same time, which is effective for obtaining a film having a surface morphology within the range of the present invention. In addition, as a method for adjusting the particle content, a high concentration master is prepared by the above method, and then diluted with a thermoplastic resin that does not substantially contain inert particles during film formation to reduce the Ml content of the particles. Control methods are effective for obtaining films with surface morphologies within the range of the present invention. Furthermore, a method in which the melt viscosity, copolymerization components, etc. of this particle-high concentration master polymer are adjusted to keep its crystallization parameter ΔTCg in the range of 30 to 80°C will not cause tearing during stretching and will produce a film with a surface morphology within the range of the present invention. It is effective for obtaining

Thus, pellet 8 containing inert particles A and B →
- After drying for 2 minutes, it is supplied to a known melt extruder and melted at a temperature above the melting point of the thermoplastic resin and below the decomposition point, and the other thermoplastic resin B (the type is non-containing) containing substantially no inert particles. The thermoplastic resin (which may be the same as or different from the thermoplastic resin containing the active particles) is fed to the above-mentioned loading device, extruded into a sheet from a slit die, and cooled and solidified on a casting roll. Make an unstretched film. These thermoplastic resins are then laminated using two or three extruders, two or three layer merging blocks, or ferrules. When using the confluence block method, the laminated portion should be rectangular as described above, and the difference in melt viscosity (absolute value) between the two thermoplastic resins should be in the range of O to 2000 voids, preferably O to 1000 voids. is effective for industrially producing a film having a surface morphology within the scope of the present invention stably and without unevenness in the width direction.

Next, this multilayer unstretched film is biaxially stretched and biaxially oriented. The biaxial stretching method may be either simultaneous biaxial stretching or sequential two-wheel stretching, but in the case of sequential biaxial stretching in which the film is stretched in the longitudinal direction and then in the width direction, the film having the surface morphology within the range of the present invention can be stabilized. , there is no unevenness in the width direction, and it is effective for industrial manufacturing. In the case of sequential biaxial stretching, the stretching in the longitudinal direction is divided into three stages, especially four or more stages, and the stretching is carried out at 40 to 150°C.
A method of stretching 3 to 6 times at a stretching speed of 1,000 to 50,000%/min is effective for obtaining a film having a surface morphology within the range of the present invention. The stretching temperature and speed in the width direction are 80 to 170°C, 1000 to 20000%/
A range of minutes is preferred. The stretching ratio is preferably 3 to 10 times. Further, if necessary, it can be further stretched in at least one of the longitudinal direction and the width direction.

In any case, the key point of the present invention is to provide an extremely thin layer containing inert particles A and B, and then stretch the layer to an areal stretching ratio (longitudinal magnification x width magnification) of 9 times or more. Next, this stretched film is heat treated.

In this case, the heat treatment conditions are preferably 140 to 280°C, preferably 160 to 220°C for 0.5 to 60 seconds in any state of relaxation, slight stretching, or constant length in the width direction. However, it is desirable to use microwave Calothermy in combination with the heat treatment because it becomes easier to obtain a film having a surface morphology within the range of the present invention.

The manufacturing method of the film of the present invention is characterized by using a highly concentrated particle polymer having a specific range of thermal properties prepared by a special method.
This method involves two-wheel stretching of the film after forming an extremely thin layer containing inert particles.In the film-forming process, the film is uniaxially stretched, then coated, etc. and roughly stretched, or biaxially stretched film. The performance of the laminated film produced by coating the film is not even close to the performance of the film of the present invention, and the film of the present invention is also superior in terms of cost.

[Method of Measuring Physical Properties and Evaluating Effects] The methods of measuring the properties and evaluating the effects of the present invention are as follows.

(1) Polyester is removed from a film of average particle size by plasma low-temperature ashing process (
For example, the particles are removed using a model PR-503 manufactured by Yamato Kagaku Co., Ltd.) to expose the particles. The processing conditions are selected so that the polyester is incinerated but the particles are not damaged. SE this
Observe with a scanning electron microscope (Scanning Electron Microscope) and use an image analyzer (for example, Cambridge Instrument MQTM900
), change the observation point and increase the number of particles to 5000fli.
The following equation 116 is performed for i1 or more, and the number average diameter I) obtained thereby is taken as the average particle diameter.

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

For inert particles B, the average particle diameter of the primary particles is 81
1 set.

(2> Particle content Select a solvent that dissolves polyester but not particles, centrifuges the particles from the polyester, and defines the particle content as the ratio (weight %) to the total weight of the particles. Depending on the case, It is also effective to use infrared spectroscopy.

(3) Crystallization parameter △TC9 Measured using DSC (differential scanning calorimeter) type ■ manufactured by Birx Elmer Co., Ltd. The measurement conditions of DSC are as follows. That is, sample 10q was set in the DSC device. , 30
After melting for 5 minutes at a temperature of 0° C., it is quenched in liquid nitrogen. This rapidly cooled sample was heated at a rate of 10°C/min, and the glass transition point T
9 is detected. The temperature was continued to rise gradually, and the peak temperature of crystallization exotherm from the glass state was defined as the cold crystallization temperature TCC. The difference between TCC and Tg (TCC-Tg>) is defined as a crystallization parameter ΔTCg.

(4) Average height of surface projections Two-detector scanning electron microscope [ESM-3200,
Elionix (manufactured by Il) and cross section measuring device [PMS-1,
The height measurement value of the protrusion was measured using an image processing device [I BAS2000. The image of the protrusions on the film surface is reconstructed on an image processing device. Next, a circular equivalent diameter is determined from the area of each protrusion obtained by binarizing the protrusion portion using this surface protrusion image, and this is taken as the average diameter of the protrusion. Furthermore, 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 value of the heights of all the measured protrusions was taken as the average height. Further, the magnification of the scanning electron microscope is selected to be between 1000 and 8000 times. In some cases, height information obtained using a high-precision optical interference type three-dimensional surface analysis device (TOPO-3D manufactured by WYKO, objective lens: 40 to 200 times, effective to use a high-resolution camera) may be used in the above-mentioned SEM. It may be used instead of the value of .

(5> Surface layer particle m degree ratio Using secondary ion mass spectrometry (SIMS:), the concentration ratio of the element with the highest concentration among the elements caused by particles in the film and the carbon element of the polyester is set to 11 degrees of the particle. , conduct an analysis in the thickness direction.

The ratio of the particle m degree A at the outermost particle m degree measured by SIMS (point at depth O) and the maximum concentration B obtained by further analysis in the depth direction, A/B is defined as the surface layer particle concentration ratio did. The measuring device and conditions are as follows.

■ Measuring device Secondary ion mass spectrometer (SIMS) DIDA3000 made by TOHIK 8, West Germany ■
Measurement conditions Primary ion species: 02" Primary ion acceleration voltage: 12KV Primary ion current: 200n raster area: 400117n analysis area 2 gates 30% Measurement vacuum degree: 6.OxlO' TorrE-GLJ
N: 0.5 KV-3, OA <6> Single particle index A cross section of the film is photographed and observed using a transmission electron microscope (Die EM) to detect particles. If the observation magnification is set to about 100,000 times, a single particle that cannot be separated any further can be observed. When the total area occupied by particles is A, and the area occupied by aggregates of 2 m or more of aggregates is B, (A-8>/A is defined as a single particle index.T
The EM conditions are as follows: 1 field of view area: 2 μm
Change the location of 811 constants and measure 500 visual fields.

・Equipment: JEOL JEM-1200EX ・Observation magnification:
100,000 times Section thickness: Approximately 1,000 angstroms (7> Particle size ratio In the measurement of (1) above, the average length of each particle is 11
/ is the ratio of the average value of the short axis.

That is, it can be obtained using the following formula.

Long axis = ΣDlt/N Short axis - ΣD2i/N Dli, D2+ are respectively (long axis (maximum diameter), short axis (shortest diameter), N is the total number of solid particles.

(8) Young's modulus according to the method specified in JIS-Z-1702,
25°C using an Instron type tensile tester.
, measured at 65°C.

(9) Thickness of thermoplastic resin layer A in the laminated film. Using a secondary ion transport spectrometer (SIMS), we determined the thickness of the thermoplastic resin A layer in the laminated film. The particle concentration is defined as the 11 degree ratio (M''/C+) of the carbon element in polyester, and analysis is performed in the depth (thickness) direction from the surface of the thermoplastic resin A layer.In the surface layer, the particle concentration is The particle S degree increases as it moves away from the surface.In the case of the film of the present invention, the particle S degree once reached a maximum value at the depth El] begins to decrease again. Depth to 1/2 of m degree [■
] (Here, n>i> is the v1 layer thickness.

The conditions are the same as in the measurement method (5>).

Note that if the particles that are present in large quantities in the film are polymeric particles, measurement using SIMS is complicated, so XPS (X-ray photoelectron spectroscopy) is performed while etching from the surface.
The depth profile of the particle concentration may be measured using an IR (infrared spectroscopy) a5 or a confocal microscope @, and the lamination thickness may be determined by the same method as described above.

In general, the laminated thickness of the thermoplastic resin A may be determined not from the depth profile of the particle concentration described above, but by observing the cross section of the film, using a thin film step measuring device, or the like.

(10) Using a tape running tester, the scratch-resistant film was slit into a 1/2 inch wide tape and run over a guide bin (surface roughness It: Ra at 10,100 nm (running speed: 111,000 m/min). , 10 passes, wrapped around corners:
60°, running crab 20g>. At this time, the scratches in the film were observed under a microscope, and if there were less than 2 grains per tape width of 2.5 μm or more, it was considered good, and if there were less than 110 grains per tape width, it was good.
0 or more were determined to be defective. Excellent is desirable, but good is still usable for practical purposes.

(11) Press one blade perpendicularly against a tape-like slit of abrasion-resistant film 1/2 inch wide, push it further 0.5M, and run it for 201J (travel tension 500g, running speed: 6. 7CIR/sec>. At this time, the height of the scraped material on the film surface attached to the tip of the single blade is read with a microscope, and the amount of scraped material is measured in units of μrrt>. When the amount of powder abrasion was 10 μm or less on at least one side, the abrasion resistance was determined to be good, and when it exceeded 10 μm, the abrasion resistance was determined to be poor.

This amount of abrasion: 116, called ioμ, is the critical point for determining whether or not problems with the process and product performance will occur due to abrasion of the film surface during processing steps such as printing and calendering. .

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

Examples 1 to 6, Comparative Examples 1 to 5 Crosslinked polystyrene particles with different average particle sizes as inert particles A, silica particles resulting from colloidal silica force, and beaded silica and reticulated titanium dioxide as inert particles B Prepare an ethylene glycol slurry containing each of
After heat treatment for 1.5 hours at
Polyethylene terephthalate (hereinafter referred to as PE) containing 6% by weight
I made a beret (abbreviated as T). That is, inert particles A and B were added at the same time during the polymerization stage. Thermoplastic resin A was prepared using the pellets, and PEIIJn containing substantially no inert particles was prepared by a conventional method to obtain thermoplastic resin B. 180% of each of these polymers
Dry for 3 hours at 30°C (3T).

r "〉Shita. Thermoplastic resin A is fed to extruder 1 and 310
Further, the thermoplastic resin E3 is supplied to the extruder 2, melted at 280°C, these polymers are merged and laminated in a confluence block equipped with a rectangular MH part, and the surface is coated using an electrostatic casting method. It was wound around a casting drum at a temperature of 30°C and cooled and solidified to produce an unstretched film with a 2] cross-section structure. At this time, 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 4.0 times in the width direction at 100°C using a stenter at a stretching speed of 20% (20%) for 7 minutes, and then heat-treated at 200'C for 5 seconds under a constant length.
Total thickness 15μ door, thermoplastic resin A layer thickness 0.008~3
A μml biaxially oriented laminated film was obtained. The parameters of the present invention for these films are as shown in Table 1, and when the parameters of the present invention were within the range, the scratch resistance and abrasion resistance showed good values as shown in Table 1. However, in other cases, a film having both properties could not be obtained.

[Effects of the Invention] As explained above, when the biaxially oriented thermoplastic resin film of the present invention is used, the inert particles contained in the laminated film layer form a desired shape on the film surface with a uniform height and high density. Inert particles B capable of forming protrusions and in agglomerated particle state
Since the projections and the film surface itself can be reinforced, the scuff resistance and abrasion resistance of the film surface can be significantly improved.

In addition, the film of the present invention is a film made by direct composite@completion by coextrusion without any operations such as coating during the film forming process, and compared to laminated films made during the film forming process or by coating afterward. Since the molecules in the outermost layer are also biaxially oriented, the strength of both the top and bottom of the film as a whole is extremely high, which is advantageous in terms of cost and quality stability.

Claims (1)

[Claims] 1. Co-extrusion of a film containing thermoplastic resin A and inert particles A and B as main components to produce a film containing thermoplastic resin B as a main component with a thickness of 0.01 μm or more on at least one side. A biaxially oriented thermoplastic resin film laminated with a laminate, wherein the average particle diameter of the inert particles A is 0.1 to 10 times the film layer thickness of the thermoplastic resin A, and the inert particles B
is a biaxially oriented thermoplastic resin film characterized in that it is agglomerated particles in which a large number of primary particles having an average particle size smaller than that of the inert particles A are connected without directionality. 2. The average particle size of the primary particles of the inert particles B is 5 to 10
The biaxially oriented thermoplastic resin film according to claim 1, which has a thickness of 0 nm. 3. The biaxially oriented thermoplastic resin film according to claim 1, wherein the content of the inert particles B in the film layer of the thermoplastic resin A is 0.05 to 1% by weight. 4. The biaxially oriented thermoplastic resin film according to claim 1, which has a Young's modulus in the width direction of 400 Kg/mm^2 or more. 5. The particle concentration ratio of the inert particles in the surface layer on the side of the laminated film containing the inert particles A and B is 0.1 or less.
The biaxially oriented thermoplastic resin film described. 6. Claim 1, wherein the thermoplastic resin A is a crystalline resin.
The biaxially oriented thermoplastic resin film described.