JPH068384B2 - Polyester composition - Google Patents

Description

TECHNICAL FIELD The present invention relates to a polyester composition, and more specifically, when formed into a film, it gives a film excellent in abrasion resistance, slipperiness, surface property and transparency. It relates to a polyester composition.

[Problems to be Solved by Prior Art and Invention]

The biaxially stretched polyester film is used as a base film in a wide range of fields such as magnetic tapes, capacitors, packaging materials and photolithography due to its excellent properties.

Generally, the polyester film is required to have good wear resistance, excellent slipperiness, and few surface coarse protrusions. In order to improve these abrasion resistance and slipperiness, a technique of giving fine irregularities to the film surface has been conventionally used. As a method of giving this fine unevenness, a method of forming protrusions on the film surface by adding fine particles (inorganic or organic particles) inert to polyester in the polyester manufacturing step or extrusion step (hereinafter, The "addition particle method" is well known.

When the additive particle method is adopted, what is important is the selection of particles, and the slipperiness, abrasion resistance, number of rough surface projections, transparency, etc. of the film remarkably differ depending on the type of particles. In particular, when a polyester composition containing particles having poor affinity with polyester is biaxially stretched to form a film, a space portion (hereinafter referred to as "internal It is called a "void"), and the particles easily fall off by a slight external force. This phenomenon directly leads to deterioration of the abrasion resistance of the film. Further, since the internal void portion has a large difference in refractive index from the polyester itself, the transparency of the entire film is significantly reduced when the volume and number of internal voids increase.

In the study by the present inventors, as particles to be added, it was revealed that the organic particles have a higher affinity with polyester as compared with the inorganic particles, and a detailed study on the organic particles will be made. As a result, a method for producing particles of a crosslinked polymer having excellent slipperiness, abrasion resistance and transparency when formed into a film was established.

However, the crosslinked polymer particles show cohesiveness due to the interaction of the functional groups on the surface thereof, and particularly when the particle size is small, the cohesiveness is remarkable. Addition of agglomerated particles to polyester is not preferable because it causes rough surface projections when formed into a film, which significantly impairs the quality of the film.

Further, in the composition containing the crosslinked polymer particles, the productivity at the time of forming a film, that is, the increase in the film formation rate has not necessarily been sufficiently achieved in the past, and higher productivity has been desired.

[Means for Solving the Problems]

The inventors of the present invention have made extensive studies in view of the above problems, and comprise crosslinked polymer particles that have been subjected to a specific surface treatment, and the specific resistance during melting is a polyester composition in a specific range. In forming a film, they have found that the particles have excellent affinity to polyester, have few surface coarse protrusions, and have high productivity, and have completed the present invention.

That is, the gist of the present invention is obtained by surface-treating particles composed of a crosslinked polymer with a copolymer containing a vinyl compound unit having a benzene ring in a side chain and an acrylic acid derivative unit, and an average particle size of 0.01 ~ 5μm particles 0.001-1
Contains 0% by weight and has a specific resistance of 1.0 × 10 ⁶ when melted.
˜1.0 × 10 ⁹ Ω · cm.

Hereinafter, the present invention will be described in detail.

In the present invention, the polyester refers to a polyester obtained from an aromatic dicarboxylic acid such as terephthalic acid or naphthalene-2,6-dicarboxylic acid or an ester thereof and ethylene glycol as a main starting material. You may contain the component. The third component is appropriately selected from isophthalic acid as the aromatic dicarboxylic acid, and propylene glycol, tetramethylene glycol, neopentyl glycol, etc. as the glycol component.

The crosslinked polymer particles used in the present invention include, for example, a monovinyl compound (A) having only one aliphatic unsaturated bond in the molecule and two or more aliphatic unsaturated bonds in the molecule as a crosslinking agent. Examples thereof include copolymers with the compound (B). In this case, such a copolymer may have a group capable of reacting with polyester.

As the compound (A) which is one component of the copolymer, acrylic acid, methacrylic acid and their methyl or glycidyl esters, maleic anhydride and its alkyl derivatives,
Examples thereof include vinyl glycidyl ether, vinyl acetate, styrene, and alkyl-substituted styrene. Examples of the compound (B) include divinylbenzene, divinylsulfone, ethylene glycol dimethacrylate and the like. One or more compounds (A) and (B) are used, but a compound having ethylene or a nitrogen atom may be copolymerized. Typical examples of these copolymers include copolymers of methyl methacrylate and divinylbenzene and copolymers of methyl acrylate and divinylbenzene.

In addition, if a crosslinked polymer having these alkyl ester groups is saponified or methacrylic acid is used instead of methacrylic acid ester, and acrylic acid is used instead of acrylic acid ester, copolymerization is easily performed, and the crosslinked polymer having a carboxyl group is easily increased. The molecule can be obtained.

Further, a copolymer of styrene and divinylbenzene can also be preferably used.

These particles may be porous, for which, when the compound (A) and the compound (B) are copolymerized, they are polymerized in the presence of the compound (C), and then the compound (C) is mixed with an organic solvent. In general, the method of removing by. Examples of the compound (C) include n-hexane, n-heptane,
Examples thereof include hydrocarbon compounds such as cyclohexane, kerosene, toluene and xylene, alcohol compounds such as n-butanol, n-hexanol and propyl alcohol, polystyrene, polyvinyl alcohol, polyalkylene oxide and the like.

In addition, as a polymerization initiator for copolymerizing the compound (A) and the compound (B), a well-known chemical radical initiator,
For example, azoisobutyronitrile, benzoyl peroxide, t
-Butyl peroxide, cumene hydroperoxide or the like is used, or the ultraviolet irradiation method is simple, but the polymerization may be initiated simply by heating.

In any case, these copolymers have a crosslinked structure,
It is preferable that the polyester is substantially insoluble and infusible even at a high temperature during the production or molding of polyester and has heat resistance.

Next, the surface treatment method of particles in the present invention will be described. As the surface treatment agent, it is necessary to use a copolymer containing a vinyl compound unit having a benzene ring in its side chain and an acrylic acid derivative unit. Vinyl compounds having a benzene ring in the side chain include styrene, divinylbenzene,
Examples thereof include, but are not limited to, stilbene. The benzene ring may be substituted with a halogen atom, an alkyl group, a hydroxyl group or the like. Styrene is particularly preferably used in the present invention. Examples of acrylic acid derivatives include acrylic acid, methacrylic acid, metal salts of these acids, ammonium salts, and esters. Among these, metal salts and ammonium salts are particularly preferably used in the present invention.

A copolymer containing these units is added to water or a crosslinked polymer particle slurry such as ethylene glycol, and sufficiently dispersed and mixed by a stirring and dispersing device (homomixer, homogenizer, etc.), or after the copolymer is added. By performing the wet pulverization treatment, the surface treatment of the crosslinked polymer particles can be performed.

The amount of the surface treatment agent added is not particularly limited, but is preferably 0.1 to 5% by weight with respect to the total amount of particles. If it is less than 0.1% by weight, the surface treatment effect is often insufficient, and if it exceeds 5% by weight, aggregation of the treatment agent itself occurs, which is not preferable.

The preparation conditions of the crosslinked polymer particles are controlled so that the average particle size of the obtained particles is in the range of 0.01 to 5 μm, or treatments such as pulverization, classification and filtration are performed. Average particle size is 0.01 μm
When it is less than 5 μm, the slipperiness and abrasion resistance when formed into a film are insufficient, and when it exceeds 5 μm, the surface roughness of the film becomes excessive, which is not preferable.

The addition amount of the surface-treated crosslinked polymer thus obtained in the polyester composition must be in the range of 0.001 to 10% by weight. When the amount added is less than 0.001% by weight, the slipperiness and abrasion resistance are insufficient when formed into a film. Further, if the addition amount exceeds 10% by weight, the surface roughness of the film becomes excessive, which is not preferable.

In the production of the polyester composition of the present invention, the additive particles are preferably added during the polyester synthesis reaction. In particular, it is preferable to add before the transesterification reaction or the esterification reaction, during the transesterification reaction or the esterification reaction, or after the completion of the transesterification reaction or the esterification reaction and before the start of the polycondensation reaction.

In addition to the surface-treated crosslinked polymer particles, fine particles of titanium dioxide, silica, kaolin, calcium carbonate or the like may be used in combination with the polyester composition of the present invention.

In addition to such fine particles, internal particles deposited by the reaction of the catalyst residue and the phosphorus compound in the polycondensation reaction system of polyester may be used in combination.

Further, the polyester composition of the present invention is required to have a specific resistance when melted of 1 × 10 ⁶ to 1 × 10 ⁹ Ω · cm, and particularly 3 × 10 ^{6 to} 5 × 10 ⁷ Ω · cm. The range of is desirable. If the specific resistance is less than 1 × 10 ⁶ Ω · cm, the thermal stability of the polymer deteriorates and it becomes difficult to form a film.

On the other hand, when the specific resistance exceeds 1 × 10 ⁹ Ω · cm, it is produced even by using the electrostatic applied cooling method (an excellent method for producing an unstretched sheet described in JP-B-37-6142). It becomes difficult to increase the film speed, and the productivity of the film is extremely deteriorated. The specific resistance of the melting degree is adjusted by solubilizing a metal compound in polyester. Usually, after completion of the transesterification reaction, the transesterification reaction catalyst, for example, magnesium compound, lithium compound, etc.
It is carried out by adding 1.0 times equivalent, preferably 0.4 to 0.8 times equivalent of a phosphorus compound.

The polyester composition of the present invention is melt-extruded to form an unstretched sheet in the form of a rotary cooling drum (preferably in combination with the above-mentioned electrostatic charge cooling method), and the temperature is 2 to 10 in the longitudinal direction at 80 to 130 ° C.
60 to 2 after being stretched at a time of 2 to 10 times in the transverse direction at 80 to 140 ° C.
A film can be formed by heat treatment at 40 ° C., but the method is not limited to this method, and the film forming conditions are appropriately selected depending on the intended use of the film.

〔Example〕

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.

The methods for evaluating physical properties and characteristics in the present invention are shown below.

(1) Average particle diameter of crosslinked polymer particles The particle diameter was measured by a centrifugal sedimentation method using Shimadzu SA-CP3.

(2) Sliding property of film Sliding property was evaluated by measuring the friction coefficient according to the method of ASTM D1894-63.

(3) Abrasion resistance of the film The abrasion resistance was evaluated by using the running system shown in FIG.
After running over a length of 000 m, the amount of adhesion on the 6 mmφ pin (surface finish 0.2S of SUS420J2) indicated by 1 due to abrasion was visually evaluated and represented by the following ranks. The traveling speed of the film is 10 m / min,
The tension is about 500g, and the winding angle (θ) with the pin is 135.
It was °.

O: Almost no adhesion

Δ: A little adhered.

X: A large amount of adhesion.

(4) Number of Coarse Protrusions Aluminum was vapor-deposited on the surface of the film and measured using a two-beam interference microscope. The number of n-th order interference fringes at the measurement wavelength of 0.54 μm is shown per 25 cm ² . The number of protrusions of 4th order or higher is shown as F ₄ , and the number of protrusions of 3rd order or higher is shown as F ₃ .

(5) Surface roughness (Ra) It was measured by the method described in JIS B0601-1976.

For measurement, manufactured by Kosaka Laboratory, surface roughness measuring instrument model SE-3
Using F, stylus diameter 2μ, stylus load 30 mg, cut-off value
It was set to 0.08 mm.

(6) Affinity of Additive Particles and Polyester As an evaluation of the affinity between the additive particles and polyester, the size of voids around the particles inside the film was observed with a polarizing microscope and represented by the following ranks.

○ ... Voids are not seen in most particles.

Δ: The number of particles with voids is slightly large.

X: Very large voids are found in the majority of particles.

(7) Haze inside film According to the method of ASTM D1003-61, liquid paraffin was applied and measured on both surfaces of the film using a turbidimeter NDH-2A manufactured by Nippon Denshoku Co., Ltd.

(8) Specific resistance of polyester when melted British Journal of Applied Physics (Brit.J.Appl.Phys) Vol. 17, 1149-1
The method described on page 154 (1966) was followed.
However, in this case, the melting temperature of the polymer composition is 290.
The value immediately after applying a DC voltage of 3000 V was taken as the specific resistance during melting.

In the examples, "part" or "%" means "part by weight" or "% by weight" unless otherwise specified.

Example 1 [Synthesis of Crosslinked Polymer Particles] Methyl methacrylate 100 parts, divinylbenzene 25
Parts, ethyl vinyl benzene 22 parts, benzoyl peroxide 1
Part, a uniform solution of 100 parts of toluene was dispersed in 700 parts of water.

Then, polymerization was carried out in a nitrogen atmosphere while stirring at 80 ° C. for 4 hours. The average particle size of the obtained crosslinked polymer particles having an ester group was about 10 μm. The produced polymer was washed with demineralized water and extracted twice with 500 parts of toluene to remove a small amount of unreacted monomer linear polymer.

[Surface Treatment Step] In the ethylene glycol slurry of the above crosslinked polymer,
As a surface treatment agent, a copolymer of polystyrene and ammonium polyacrylate was added to the particles in an amount of 1.0%, and then pulverized using a sand grinder,
A particle slurry having an average particle size of 1.2 μm was obtained. This slurry is wet-classified and filtered to obtain an average particle size of 1.0 μm, 20%.
A concentration slurry was obtained.

[Production of Polyester Composition] 100 parts of dimethylene terephthalate, 60 parts of ethylene glycol, and 0.09 part of magnesium acetate / tetrahydrate are placed in a reactor, heated and heated, and methanol is distilled off to carry out a transesterification reaction. After 4 hours from the start of the reaction, the temperature was raised to 230 ° C., and the transesterification reaction was substantially completed. Then, ethyl acid phosphate 0.0
After adding 4 parts (in this case, 0.7 times the equivalent of the phosphorus compound to the magnesium compound will be added), the ethylene glycol slurry having the above average particle diameter of 1.0 μm
Addition of 1.5 parts (the particle content is 0.3% based on the obtained polyester resin), and antimony trioxide is added.
0.04 part was added and polycondensation was carried out for 4 hours to obtain a polyethylene terephthalate polymer. The specific resistance of the obtained polymer when melted was 5 × 10 ⁶ Ω · cm.

[Production of Film] The obtained polymer is heated and dried at 180 ° C. in a nitrogen atmosphere for 6 hours, melt-extruded by an extruder, and a 220 μm sheet-like material is formed by an electrostatic cooling method, and then 85 ° C. in the longitudinal direction. The film is stretched 3.7 times in the transverse direction and further stretched 4 times in the transverse direction at 90 ° C, and then heat treated at 220 ° C for 5 seconds to give a thickness of 15 μm.
A biaxially stretched polyethylene terephthalate film was obtained.

At this time, the speed at which a film can be formed without binding bubbles by the electrostatic applied cooling method, that is, the maximum rotation speed of the cooling drum is 6
It was possible to achieve a high speed of 0 m / min, and the film productivity was good.

Example 2 A polyester composition was obtained in the same manner as in Example 1 except that 2% of the surface treatment agent was used and the average particle diameter of the added particles was 0.3 μm. A film having a thickness of 15 μm was obtained in the same manner as in.

Comparative Example 1 A polyester composition was obtained in the same manner as in Example 1 except that the average particle size of the crosslinked polymer particles to be added was 1.0 μm and no surface treatment was added and no surface treatment was carried out to obtain a polyester composition.
A film having a thickness of 15 μm was obtained in the same manner as in.

Comparative Example 2 A polyester composition was obtained in the same manner as in Example 1 except that the amount of the crosslinked polymer particles added was 0.0005% by weight. 1
A film of 5 μm was obtained.

Comparative Example 3 A polyester composition was obtained in the same manner as in Example 1, except that the addition amount of the crosslinked polymer particles to be added was 15% by weight, and a film was formed in the same manner as in Example 1 to have a thickness of 15 μm.
I got a film of.

Comparative Example 4 Example 1 was repeated except that the amount of ethyl acid phosphate added after the completion of the transesterification reaction was 0.2 part.
A polyester composition was obtained in the same manner as in.

The specific resistance of the obtained composition at the time of melting was as high as 5 × 10 ⁹ Ω · cm, and then a biaxially stretched film was produced in the same manner as in Example 1, but at that time, a film was formed without binding bubbles. The speed that can be achieved, that is, the maximum number of rotations of the cooling drum was as slow as 20 m / min, and the productivity of the film was poor.

The results obtained above are summarized in Table 1.

[Effects of the Invention] The polyester composition containing the crosslinked polymer particles subjected to the special surface treatment of the present invention has a high affinity between the polyester and the particles, and the dispersibility of the particles is extremely improved. . A film using such a polyester composition has very few particles falling off, has excellent abrasion resistance, has few internal voids, and thus has high transparency and has very few rough surface protrusions.

Therefore, the polyester composition of the present invention can be applied to a wide variety of films such as magnetic tapes, capacitors, packaging materials, and photolithography, and its industrial value is high.

[Brief description of drawings]

FIG. 1 is a schematic diagram of a running system for evaluating the abrasion resistance of the film, and (I) in the figure is 6 mmφ SUS420-J2 0.2.
A fixed pin with S surface finish, (II) is a tension pickup. Further, the film winding angle θ of the fixed pin is 135 °.

Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display area C08L 33:02) B29K 67:00 4F B29L 7:00 4F

Claims (1)

[Claims] 1. An average particle diameter of 0.01 to 5 μm obtained by surface-treating particles of a crosslinked polymer with a copolymer containing a vinyl compound unit having a benzene ring in a side chain and an acrylic acid derivative unit. It contains particles in an amount of 0.001 to 10% by weight, and has a specific resistance of 1.0 × 10 ^{6 to} 1.0 × 10 ⁹ when melted.
A polyester composition characterized in that it is Ω · cm.