JPH03239731A - Biaxially oriented polyester film - Google Patents

Abstract

PURPOSE:To obtain the title film improved in slidability, abrasion resistance and workability during film production by adding two kinds of specified heat- resistant cross-linked polymer particles having a mean particle diameter different from each other to a biaxially oriented polyester film. CONSTITUTION:The purpose biaxially oriented polyester film contains crosslinked polymer particles A containing ethylene glycol units and having a weight loss of 30wt.% or below upon heating at 300 deg.C for 30min and a mean particle diameter of 0.05-3mum and particles B having a mean particle diameter below 0.7 time larger than that of particles A and/or particles C having a mean particle diameter above 1.4 times larger than that of particles A. Particles A can be obtained, for example, by the homopolymerization of a compound of formula I (wherein R<1> is hydrogen or 1-4C linear or branched alkyl; R<2> is hydrogen or a group of formula II; and n is an integer of 1 or greater) or the copolymerization thereof with a copolymerizable compound. As particles B and C, crosslinked polymer particles, particles precipitated in the polyester synthesis reaction system, inorganic particles or the like can be used.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a biaxially oriented polyester film that has excellent flatness and easy sliding properties, abrasion resistance, and improved winding properties.

[Prior art and problems to be solved by the invention] Polyester films have excellent physical and chemical properties and are widely used as industrial materials. In particular, two-wheel oriented polyethylene terephthalate films are prized as base films for magnetic recording media and capacitor dielectrics because of their excellent mechanical strength, dimensional stability, flatness, and the like. Furthermore, due to its excellent transparency, it is widely used in fields such as graphic arts, displays, and packaging materials.

Incidentally, when these films are actually handled, they are required to have excellent running properties and abrasion resistance, but these properties have not always been fully achieved in the past.

For example, when films come into contact with each other or a film and a base material at high speed, friction and abrasion between the two increases, causing scratches on the film and generation of abrasion powder.

This abrasion powder causes a loss of recording signals, that is, dropout, in, for example, magnetic recording applications, and significantly reduces the commercial value of the film.

It is generally known that in order to improve the running properties and abrasion resistance of a film, it is sufficient to appropriately roughen the film surface. In order to achieve this, a method has been adopted in which fine particles are present in the raw polyester, and some have been put into practical use, but a flat film with improved workability and abrasion resistance at the same time I wasn't getting it.

[Means to solve the problem]

In view of these circumstances, the inventors of the present invention have made extensive studies to provide a film with a flat surface, excellent slipperiness and abrasion resistance, and improved workability during film production, especially winding characteristics. The present inventors have found that such required characteristics can be satisfied by including particles having an average particle size different from a certain specific crosslinked polymer particle and the average particle size of the particle, and have completed the present invention.

That is, the gist of the present invention is to provide crosslinked polymer particles (having ethylene glycol units) having a weight loss rate of 30% by weight or less after treatment at 300°C for 30 minutes and an average particle size of 0.05 to 3 μm. A) and particles (B) whose average particle size is less than 0.7 times that of particles (A) and/or particles (C) whose average particle size is 1.4 times or more that of particles (A). It consists in a biaxially oriented polyester film made of

The present invention will be explained in detail below.

The polyester referred to in the present invention refers to terephthalic acid, 2.6
- It refers to a polyester obtained using an aromatic dicarboxylic acid such as naphthalene dicarboxylic acid or its ester and ethylene glycol as the main starting materials, but it may contain other third components. In this case, the dicarboxylic acid component includes, for example, isophthalic acid, phthalic acid, 2.
6-naphthalene dicarboxylic acid, terephthalic acid, adipic acid, sebacic acid, and oxycarboxylic acid components such as p
-Oxyethoxybenzoic acid or the like can be used alone or in combination of two or more. As the glycol component, one or more of diethylene glycol, propylene glycol, butanediol, 1,4-cyclohexane dimetatool, neopentyl glycol, etc. can be used. In any case, the polyester of the present invention refers to a polyester in which 80% or more of repeating structural units have ethylene terephthalate units or ethylene-2,6-naphthalene units.

Further, the polyester film of the present invention refers to a polyester film oriented in two wheels using such a polyester as a starting material, and a known method can be used as a manufacturing method thereof. For example, it is usually melt-extruded into a sheet at 270-320°C, cooled and solidified at 40-80°C to form an amorphous sheet, then finally biaxially stretched or simultaneously stretched in the longitudinal and transverse directions, and then heat-treated at 160-250°C. Methods such as (for example, the method described in Japanese Patent Publication No. 30-5639) can be used. When stretching in the longitudinal and transverse directions, stretching may be carried out in each stage, or if necessary, stretching may be carried out in multiple stages, or a heat treatment section for orientation relaxation may be provided between multi-stage stretching. Also, after biaxial stretching,
It may be stretched again before being subjected to the next heat treatment step.

This re-stretching can be carried out in either the longitudinal or lateral directions, or in both directions.

The purpose of the present invention is to incorporate crosslinked polymer particles (A) containing ethylene glycol units as a first component and having excellent heat resistance and affinity with polyester into polyester, and further improve the film properties. In order to do
The purpose is to contain at least one particle having an average particle diameter different from that of the crosslinked polymer particles (A).

The average particle diameter of the crosslinked polymer particles (A), which is the first component, is 0.
The range is 0.05 to 3 μm, preferably 0.1 to 2 μm.
is within the range of If the average particle size is less than 0.05, the effect of improving the surface properties and abrasion resistance of the film is insufficient. Moreover, if it exceeds 3 μm, the surface roughness of the film becomes too large, the mixture of large particles increases, and the quality of the film deteriorates, which is not preferable.

The average particle diameter of the particles used in combination with particles (A) is the above particle (A).
It is less than 0.7 times or more than 1.4 times the average particle diameter of.

When crosslinked polymer particles containing ethylene glycol units, which are particles of the first commandment, and have excellent heat resistance are used alone, they have good affinity with polyester and have excellent abrasion resistance, but the film Wrapping tends to occur when winding at high speed. Containing particles with different average particle sizes improves the winding characteristics at high speeds, but particles with an average particle size close to the average particle size of the crosslinked polymer particles, which are the first component, do not have the same improvement effect. Even if it is sufficient, winding misalignment remains when winding at high speed.

The total amount of particles contained in the film is 0,005~
1% by weight is preferred, more preferably 0.03-0.6
% by weight.

Next, each particle contained in the film of the present invention will be explained in detail.

The 11th crosslinked polymer particles (A) used in the present invention have two characteristics.

One of them is that the crosslinked polymer particles (A) contain ethylene glycol units (-CH2CH20-). The content of ethylene glycol units in the crosslinked polymer particles is usually in the range of 3 to 38% by weight, preferably in the range of 5 to 25% by weight. If the content of ethylene glycol units is less than 3% by weight, it is not preferable because it aggregates to form secondary particles when blended with polyester.

The inclusion of ethylene glycol units in the particles increases their affinity with polyester, and some of them react with the polyester and can be embedded in the polyester as particles with strong bonds to the polyester. It is possible to significantly improve the drop-off of particles caused by friction and abrasion with the magnetic head, guide bin, etc. during tape running as described in . A further unexpected effect is that the dispersibility of the particles in polyester is dramatically improved.

The second feature of the crosslinked polymer particles (A) used in the present invention is:
It has heat resistance. That is, in the present invention, the weight reduction rate of the crosslinked polymer particles after being treated at 300° C. for 30 minutes is 30% by weight or less, preferably 20% by weight or less. Crosslinked polymer particles whose weight loss rate exceeds 30% by weight are
Melts and decomposes during the manufacturing process of polyester molded products.

Crosslinked polymer particles (A) having such characteristics can be produced, for example, by the method shown below.

That is, it can be produced by polymerizing a compound having an ethylene glycol unit in the molecule, for example, the compound shown in Mon'ena (1) below, or by copolymerizing the compound and a compound copolymerizable with the compound. can.

However, in the above formula, R1 represents a hydrogen atom or a Cl-Ca linear or branched alkyl group, and R1 represents a hydrogen atom or a compound represented by general formula (11), in particular ethylene glycol mono Acrylate, ethylene glycol methacrylate, ethylene glycol diacrylate, ethylene glycol, cold dimethacrylate, etc. are preferably used.

In addition, compounds that can be copolymerized with these compounds include:
Examples include, but are not limited to, acrylic esters such as methyl acrylate and ethyl acrylate, methacrylic esters such as methyl methacrylate and ethyl methacrylate, and aromatic vinyl compounds such as styrene and divinylbenzene.

The crosslinked polymer particles (A) used in the present invention can be obtained by polymerizing the compounds exemplified above, but it is preferable to apply an emulsion polymerization method to the polymerization. The emulsion polymerization method referred to herein refers to emulsion polymerization in a broad sense, including concepts such as soap-free polymerization and seed polymerization.

For example, after dissolving a predetermined amount of a water-soluble polymerization initiator in an aqueous medium, the compound represented by the above-mentioned -Momonena (L) and a vinyl compound, which have been previously purified by a conventional method, are mixed uniformly and added. The bath ratio (monomer/water ratio) is usually 1/30.
~115.

A bath ratio of less than 1/30 is not preferred because productivity is poor. Further, if the bath ratio is 115 or more, aggregated particles are likely to be formed, which is not preferable.

Next, polymerization is carried out under stirring at a temperature higher than the decomposition start temperature of the polymerization initiator, preferably 40 to 80°C for 6 to 8 hours.

At this time, some aggregated particles may be formed depending on the seven-dimensional precept, so in this case, a dispersion stabilizer may be added to maintain the dispersion stability of the particles. As the water-soluble polymerization initiator, a redox initiator such as hydrogen peroxide, potassium persulfate, or potassium persulfate-sodium thiosulfate can be used. In this case, since the crosslinked polymer particles (A) are obtained as a uniformly decomposed water slurry, it is preferable to replace them with ethylene glycol slurry for blending with polyester, or to take them out as dry particles.

The crosslinked polymer particles (A) used in the present invention are preferably substantially insoluble and infusible even at the bottom of the polyester or at high temperatures during molding. That is, the crosslinked polymer particles (A) contain alcohols such as methanol and ethanol, ethylene glycol, propylene glycol, 1
, 4-butanediol and other glycols, bis-(β-hydroxyethyl) terephthalate and its oligomers, and even polyesters, it is preferably almost insoluble even at high temperatures.

A typical example of a crosslinked polymer particle, which is one of the particles that can be used as particles (B) and particles (C), is
For example, as described in Japanese Patent Publication No. 59-5216, a monovinyl compound having only one aliphatic unsaturated bond in the molecule and a crosslinking agent containing two or more aliphatic unsaturated bonds in the molecule. Examples include copolymers with compounds having the compound, but are not limited to these, for example, thermosetting phenol resins, thermosetting epoxy resins, thermosetting urea resins, penzoguanine resins, and polyesters. Fine powder of fluororesin such as tetrafluoroethylene can also be used.

In the present invention, when crosslinked polymer particles are used as the second and third components, it is particularly preferable that the particles have the same composition as the crosslinked polymer particles in the first component.

Particles precipitated in a polyester synthesis reaction system can also be used as particles (B) and particles (C) of the present invention,
For example, a transesterification reaction is carried out in the presence of a lithium compound and/or a calcium compound, and after completion of the transesterification reaction, one or more compounds selected from the group consisting of phosphoric acid, phosphorous acid, or their alkyl esters or aryl esters are added. 0.6 for the total amount of these metal compounds
Examples include particles precipitated in polyester obtained by adding ~3 equivalents and subsequently performing a polycondensation reaction.

In this case, the lithium compound used may be any lithium compound as long as it is soluble in the esterification or transesterification reaction product, such as salts of aliphatic carboxylic acids such as acetic acid, propionic acid, butyric acid, benzoic acid, p-methylbenzoic acid, etc. Examples include salts of aromatic carboxylic acids, and lithium glycolates such as ethylene glycol and propylene glycol.

Among these, lithium aliphatic carboxylates, particularly lithium acetate, are preferred. The amount used is preferably 0.03 to 0.4 mol%, particularly 0.1 to 0.3 mol%, based on the aromatic dicarboxylic acid component.

There are no particular restrictions on the calcium compound as long as it dissolves in the esterification or transesterification product, such as salts of aliphatic carboxylic acids such as acetic acid, propionic acid, and butyric acid, benzoic acid, and p-methylbenzoic acid. Examples include salts of aromatic carboxylic acids such as ethylene glycol, propylene glycol, and calcium glycolates. Among these, calcium aliphatic carboxylates, particularly calcium acetate, are preferably used.

Further, the amount of calcium compound is 0.05 to 0.3 mol%, especially 0.08 to 0.15 mol% based on the aromatic dicarboxylic acid component.
Mol% is preferably used.

The phosphorus compound may be one that can react with the above-mentioned metal compound to convert part or all of it into a phosphate or phosphite derivative 6, but in particular phosphoric acid, a trialkyl ester of phosphoric acid, and a phosphorus compound can be used. partial alkyl esters of acids;
Phosphous acid, trialkyl esters of phosphorous acid, and partial alkyl esters of phosphorous acid are preferably used.

The amount of these phosphorus compounds added is 0.6 to 3 times equivalent, preferably 0.8 to 2 times equivalent, and more preferably 0.9 to 1.5 times equivalent relative to the total amount of metal compounds.

Note that the equivalent ratio of the phosphorus compound to the metal compound is expressed by the following formula % (in the formula, P, Ca, and Li represent the number of moles of the phosphorus compound, calcium compound, and lithium compound, respectively).

By using the metal compound and the phosphorus compound in combination as described above, precipitated particles containing the metal element and the element used in the particles can be obtained. Of course, part or all of the lithium compound or calcium compound may be added after the transesterification reaction is completed.

The amount of precipitated particles is determined as follows.

Quantification of precipitated particles in polyester film: 1.0-chlorophenol to 100 g of polyester. Add Ol and 12
After heating at 0°C for 3 hours, use a Beckman ultracentrifuge L3-5.
Centrifugation is carried out at 30.00 rpm for 40 minutes using 0.05 cm, and the resulting particles are vacuum dried at 100°C. When the particles are measured with a scanning differential calorimeter, if a melting peak corresponding to the polymer is observed, 0-chlorophenol is added to the particles, heated and cooled, and then centrifuged again.

When the melting peak is no longer observed, the particles are treated as precipitated particles and the weight ratio to the polyester is calculated.

In addition, inorganic particles also include particles (B) and particles (C) of the present invention.
Specific examples include kaolin, talc, carbon, molybdenum sulfide, gypsum, rock salt, calcium carbonate, barium sulfate, lithium fluoride, calcium fluoride, zeolite, calcium phosphate, silicon dioxide, titanium dioxide, etc. I can do it. However, although these inorganic particles are usually obtained by crushing or crushing natural minerals, coarse particles and aggregated particles may be mixed therein.

If coarse particles and large particles due to agglomeration coexist in polyester, they may clog the filter during the extrusion process, break the film during film formation, and cause dropouts in magnetic tape due to minute defects called fish eyes in the film. This causes problems such as poor withstand voltage in capacitors and capacitors. Particularly in the field of magnetic tape in recent years, there has been a desire for precision through miniaturization, longer operation times, and higher image quality. Therefore, it is necessary to make the unevenness on the film surface more uniform and fine.

For this purpose, a method has been proposed in which inert inorganic particles are pulverized and classified in advance to remove coarse particles. For example, the powder obtained by crushing natural raw stone or the powder obtained by crushing is further subjected to a dry or wet crushing process,
A method is known in which the material is then subjected to dry or wet classification treatment.

The method of adding particles used in the present invention to polyester is not particularly limited, and any known method may be employed.
For example, it may be added as an ethylene glycol slurry at any stage of the polyester manufacturing process, preferably after the end of esterification or transesterification but before the start of the polycondensation reaction, to proceed with the polycondensation reaction, or particles and polyester chips You can also directly blend them.

〔Example〕

EXAMPLES Hereinafter, the present invention will be explained in more detail with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist thereof. In the examples and comparative examples, "parts" indicate "parts by weight."

Furthermore, the measurement method used in the present invention is as follows.

Ethylene glycol unit What is the ethylene glycol unit in the crosslinked polymer particle?-C4
1,-C12-0-, and its ratio was determined from the following formula.

Proportion of ethylene glycol units (wt%) = average particle size For particles precipitated in the reaction system, the polyester containing the precipitated particles is dissolved using a phenol/tetrachloroethane-2/3 solvent, and then microtrunk ( (manufactured by Nikkiso Co., Ltd.) to determine the average particle size.

The particle sizes of other particles were measured using an electron microscope. The average particle size was calculated as the particle size (diameter) at a point where the weight fraction of the equivalent sphere was 50%.

Using a thermal analyzer DT-20Bs type manufactured by Shimadzu Corporation, the temperature was measured from room temperature to 10°C under nitrogen gas flow (200 ml/min).
The weight loss rate of the crosslinked polymer particles after heating to 300° C. at a heating rate of /mtn and holding at 300° C. for 30 minutes was determined from the following formula.

Weight reduction rate (weight %) = Surface roughness is defined as weight loss before heating and center line average roughness Ra (μm),
It was determined as follows using a surface roughness measuring machine (SE3F) manufactured by Koita Research Institute. That is, a part of the reference length (2.5 m5) is extracted from the film cross-sectional curve in the direction of its center line, and the roughness curve y=f ( x), the value given by the following formula is expressed in [μm]. The centerline average roughness was determined by determining 10 cross-sectional curves from the surface of the sample film, and was expressed as the average value of the centerline average roughness of the sampled portions determined from these cross-sectional curves. The tip radius of the stylus is 2 μm, the load is 30μ, and the cutoff value is 0.0.
It was set to 8m.

Using the device shown in Figure 1, the film is wrapped around a fixed hard chrome metal roll (diameter 61 m) at an angle of 135°.
(θ), apply a load of 53 g (Tz) to one end, run it at a speed of 1 m/min, measure the resistance force (T + (g)) at the other end, and calculate the friction during running using the following formula. The coefficient (μd) was determined.

The film was run for 200 m using the running system shown in FIG. 2, and the amount of abrasion white powder adhering to a fixed bottle made of hard chrome with a diameter of 6 u was visually evaluated and evaluated according to the ranks shown below. The film speed was 10+/a+in, the tension was about 200 g, and θ=135°.

Rank A: No adhesion at all Rank C: A small amount of adhesion Rank C: A small amount of adhesion (more than rank B) Rank D: Extremely large amount of adhesion Large number of protrusions Aluminum is vapor-deposited on the surface of the film, and an interference microscope is used to deposit three light beams. Measured using the method. The number of protrusions exhibiting third-order or higher-order interference fringes at a measurement wavelength of 0.54 μm was determined by measuring for 25 days.

1. The appearance of the roll surface and roll end surface when the film was rolled up into a roll was evaluated in the following three grades.

A roll with almost no wrinkles or burr-like defects on the roll surface and a uniform roll end face ○ A roll with almost no wrinkles on the roll surface but some burr-like defects and a slightly uneven roll end face △ A roll with wrinkles on the roll surface or roll end faces are irregular ×Example 1 <Crosslinked polymer particles containing ethylene glycol units (
Production of a) 0 parts of water-soluble polymerization initiator potassium persulfate in 100 parts of demineralized water
．． After adding 0.004 parts of Emar O (sodium lauryl sulfate; manufactured by Kako Atlas Co., Ltd.) as a dispersion stabilizer and uniformly dissolving the mixture, a homogeneous solution of 9 parts of styrene and 1 part of divinylbenzene was added.

Next, the temperature was raised to 70°C while stirring in a nitrogen gas atmosphere.
Time polymerization was performed. The average particle size of the obtained crosslinked polymer particles was 0.77 μm. Additionally, add 300 g of demineralized water to the reaction system.
parts, 2.1 parts of ethylene glycol dimethacrylate,
A homogeneous mixture of 0.6 parts of methyl methacrylate and 0.3 parts of divinylhenzea was added, and polymerization was carried out at 70°C for 6 hours. The reaction yield was 99%, and the average particle size of the particles obtained was 0.
．． It was 82 μm, and the weight reduction rate after heat treatment at 300° C. for 30 minutes under nitrogen was 13%.

240 parts of ethylene glycol was added to the resulting water slurry of crosslinked polymer particles, heated, and water was distilled off under reduced pressure.

(Production of cross-linked polymer particles (BL)) Add 0 potassium persulfate, a water-soluble polymerization initiator, to 120 parts of demineralized water.
．． After adding 32 parts of Emar O (sodium lauryl sulfate: Kako Atlas Co., Ltd.) as a dispersion stabilizer and 4 parts of OOO and uniformly dissolving it, 7 parts of ethylene glycol dimethacrylate, 2 parts of methyl methacrylate and 1 part of divinylbenzene were added. solution was added.

Next, the temperature was raised to 70°C while stirring under a nitrogen gas atmosphere,
Polymerization was carried out at 70°C for 6 hours. The reaction rate was 99%, and the average particle diameter of the crosslinked polymer particles obtained was 0°30 μm.

190 parts of ethylene glycol was added to the resulting water slurry of crosslinked polymer particles, and water was distilled off under heating and reduced pressure.

(Manufacture of polyester film) 100 parts of dimethyl terephthalate, 60 parts of ethylene glycol, and 0.09 parts of magnesium acetate tetrahydrate were placed in a reactor, heated to raise the temperature, and methanol was distilled off to perform a transesterification reaction. It took 4 hours 2
The temperature was raised to 30°C, and the transesterification reaction was substantially completed.

Next, an ethylene glycol slurry containing 0.04% of crosslinked polymer particles FAL with an average particle size of 0.82 μm was added, and then 0.04 parts of ethyl acid phosphate and 0.035 parts of antimony trioxide were added, and the mixture was heated for 4 hours. Polyethylene terephthalate with an intrinsic viscosity of 0.66 (
1) was obtained.

Perform the transesterification reaction in the same manner as in the production of raw material (1),
Next, after adding ethylene glycol slurry containing 0.40% of crosslinked polymer particles with an average particle diameter of 0.30 μm, polycondensation was performed in the same manner as raw material (1) to obtain polyethylene terephthalate with an intrinsic viscosity of 0.66. (■) was obtained.

Next, raw materials (I) and (II) were mixed in a blender at a weight ratio of 50,150 and dried at 285°C.
Melt extrusion was performed to obtain an amorphous film with a thickness of 185 μm.

Next, the film was stretched 3.5 times in the longitudinal and transverse directions, heat-set at 190° C., and then cooled to obtain a two-wheel stretched film with a thickness of 15 μm.

Example 2 100 parts of dimethyl terephthalate, 70 parts of ethylene glycol, 0.10 parts of calcium acetate hydrate, and 0.17 parts of lithium acetate dihydrate were placed in a reactor and heated to raise the temperature, and methanol was distilled off to perform a transesterification reaction. The temperature was raised to 230° C. about 4 hours after the start of the reaction, and the transesterification reaction was substantially completed.

Next, after heating this reaction product to 235°C, 0.30 part of triethyl phosphate (1.2 times equivalent to the metal compound) was added, and then 0.05 part of antimony trioxide was added. Polymerized according to the method, average particle size 0.45μm
Polyester (I) containing 0.4 parts mt% of precipitated particles of
[[] was obtained, and then mixed with polyester (I) at a weight ratio of 50,150, and further in the same manner as in Example 1 to obtain a polyester film.

Example 3 In Example 1, instead of the particles -), heavy calcium carbonate particles (b) with an average particle diameter of 0.43 μm that had been subjected to wet grinding, wet classification, and filtration were used, and the same procedure as in Example 1 was carried out. A polyester film was obtained by the method.

Example 4 In Example 1, the crosslinked polymer particles (a) in polyester (I) were changed to crosslinked polymer particles (bl), and the content was changed to 0.
4 wt%, and the crosslinked polymer particles ('b) in polyester (II) were changed to heavy calcium carbonate particles (C) with an average particle diameter of 0.80 μ which were subjected to known wet grinding, wet classification and filtration treatment, A polyester film was obtained in the same manner as in Example 1 except that the content was 0.04 wt%.

Comparative Example 1 A polyester film was obtained in the same manner as in Example 3 except that the crosslinked polymer particles (a) were not contained.

Comparative Example 2 Example 4 was repeated except that the average particle size of the second precept (C1) was changed to 0.30 μm.
A polyester film was obtained in the same manner.

Comparative Example 3 In Example 1, the crosslinked polymer particles in polyester (1) + a) were replaced by heavy calcium carbonate particles with an average particle size of 0.43 μm! A polyester film was obtained in the same manner as in Example 1, except that in d), the crosslinked polymer particles (b) in polyester (II) were replaced with spherical silica having an average particle size of 0.75 μm.

The results obtained above are summarized in Table 1 below.

〔Effect of the invention〕

The film of the present invention has good properties of crosslinked polymer particles, especially excellent flatness and ease of winding without losing abrasion resistance, and can be suitably used for various applications.
Its industrial value is high.

[Brief explanation of drawings]

Figure 1 shows a running system for evaluating the coefficient of dynamic friction with metal.
(1) is a 6nφ hard chrome plating fixing pin, (n) is an inlet tension meter, (III) is an outlet tension meter, and θ is 135". Figure 2 shows the running system for evaluating wear resistance. , (TV) is a fixed bottle made of hard chrome with a diameter of 611 m, (V) is a tension meter, and θ is 135°.

Claims (1)

[Claims] (1) Crosslinked polymer particles (A) having ethylene glycol units, which have a weight loss rate of 30% by weight or less after treatment at 300°C for 30 minutes and have an average particle size of 0.05 to 3 μm; 2 containing particles (B) whose average particle size is less than 0.7 times that of particles (A) and/or particles (C) whose average particle size is 1.4 times or more that of particles (A). Axially oriented polyester film.