JPH02245056A - Polyester composition - Google Patents

Abstract

PURPOSE:To prepare a polyester compsn. which gives a film excellent in the abrasion resistance, slipperiness, surface properties, and transparency by compounding specific org. particles into a polyester, thereby keeping the specific resistance of the polyester, when it is fused, in a specified range. CONSTITUTION:0.001-10wt.% particles with a mean particle diameter of 0.01-5mum obtd. by coating the surface of particles comprising a crosslinked polymer (e.g. a polymer of methyl methacrylate, divinylbenzene, and etylvinylbenzene) with a copolymer having in its side chain a vinyl monomer unit with a benzene ring (e.g. styrene) and an acrylic acid deriv. unit (e.g. polyammonium acrylate) is compounded into a polyester (e.g. polyethylene terephthalate), and thus the specific resistance of the polyester, when it is fused, is kept in 1.0X10<6>-1.0X10<9>OMEGA.cm.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a polyester composition, and more particularly, to a polyester composition that, when formed into a film, provides a film with excellent abrasion resistance, easy sliding properties, surface properties, and transparency. The present invention relates to polyester compositions.

[Prior Art and Problems to be Solved by the Invention] Due to its excellent properties, biaxially oriented polyester film is used as a base film in a wide range of fields such as magnetic tapes, capacitors, packaging materials, and photolithography.

Such polyester films are required to have - good abrasion resistance for boat fishing, excellent slipperiness, and a small number of rough protrusions on the surface. In order to improve these abrasion resistance and slipperiness, a method of providing fine irregularities on the film surface has been used. As a method for providing these fine irregularities, a method (hereinafter referred to as (referred to as the "added particle method") is well known.

When employing the additive particle method, the important thing is the selection of particles, and the slipperiness, abrasion resistance, number of coarse protrusions on the surface, transparency, etc. of the film vary significantly depending on the type of particles. In particular, when a polyester composition containing particles that have poor affinity with polyester is biaxially stretched to form a film, due to the effect of stretching stress, the particle surface and the polyester peel off near the particle surface, resulting in spaces (hereinafter referred to as "internal"). (referred to as "voids"), and particles easily fall off due to a slight external force. This phenomenon is directly linked to deterioration of the abrasion resistance of the film. Furthermore, since the refractive index of the internal voids is significantly different from that of the polyester itself, as the volume and number of internal voids increases, the transparency of the entire film decreases significantly.

The inventors' study revealed that organic particles have a better affinity with polyester than inorganic particles, and a detailed study on organic particles was conducted. As a result, we established a method for producing crosslinked polymer particles that have excellent slipperiness, abrasion resistance, and transparency when formed into a film.

However, crosslinked polymer particles exhibit aggregation properties due to interactions between functional groups on their surfaces, and the aggregation properties are particularly noticeable when the particle size is small. Adding aggregated particles to polyester is not preferable because it causes rough protrusions on the surface when formed into a film, significantly impairing the quality of the film.

Furthermore, compositions containing crosslinked polymer particles have not always been able to sufficiently increase the productivity when forming into a film, that is, the film forming speed, and higher productivity has been desired.

[Means to solve the problem]

As a result of intensive studies in view of the above-mentioned problems, the present inventors have found that a polyester composition containing crosslinked polymer particles subjected to a certain surface treatment and having a specific resistance when melted is within a certain range. They found that the particles have excellent affinity for polyester, have few rough surface protrusions, and have high productivity when formed into a film, and have completed the present invention.

That is, the gist of the present invention is to obtain particles with an average particle size of 0.01 that are obtained by surface treating particles made of a crosslinked polymer with a copolymer containing a vinyl compound unit having a benzene ring in the side chain and an acrylic acid derivative unit. 0.001 ~5μm particles
Contains ~10% by weight, and the specific resistance value when melted is 0X
A polyester composition characterized by having a resistance of 10 6 to 1.0×10 9 Ω·.

The present invention will be explained in detail below.

In the present invention, polyester refers to a polyester obtained using an aromatic dicarboxylic acid such as terephthalic acid or naphthalene-2,6-dicarboxylic acid or an ester thereof and ethylene glycol as main starting materials; It may contain ingredients. The third component is appropriately selected from isophthalic acid as an aromatic dicarboxylic acid, and propylene glycol, tetramethylene glycol, neopentyl glycol, etc. as a 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 a monovinyl compound (A) having two or more aliphatic unsaturated bonds in the molecule as a crosslinking agent. Examples include copolymers with compound ('B) having In this case, such copolymers may have groups capable of reacting with the 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 include vinyl glycidyl ether vinyl acetate, styrene, and alkyl-substituted styrene. Further, examples of the compound (B) include divinylbenzene, divinyl sulfone, ethylene glycol dimethacrylate, and the like. One or more types of each of compounds (A) and (B) are used, but a compound having ethylene or a nitrogen atom may be copolymerized. Typical examples of these copolymers include:
Examples include copolymers of methyl methacrylate and divinylbenzene, and copolymers of methyl acrylate and divinylbenzene.

In addition, if these crosslinked polymers having alkyl ester groups are saponified or copolymerized using methacrylic acid instead of methacrylic esters and acrylic acid instead of acrylic esters, crosslinked polymers having carboxyl groups can be easily obtained. molecules can be obtained.

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

These particles may be porous, and for that purpose, when copolymerizing compound (A) and compound (B), the polymerization is carried out in the presence of compound (C), and then compound (C) is dissolved in an organic solvent. Generally, the method of removing Compound (C
), for example, hydrocarbon compounds such as n-hexane, n-hebutane, cyclohexane kerosene, toluene, xylene, alcohol compounds such as n-butanol, n-hexanol propyl alcohol, and polystyrene,
Examples include polyvinyl alcohol and polyalkylene oxide.

In addition, as a polymerization initiator for copolymerizing compound (A) and compound (B), well-known chemical radical initiators,
For example, azoisobutyronitrile benzoyl peroxide, t-
Butyl peroxide.

Although cumene hydroperoxide or the like or ultraviolet irradiation is convenient, polymerization may also be initiated simply by heating.

In any case, these copolymers have a crosslinked structure,
It is preferable to use a material that is substantially insoluble, infusible, and heat resistant even at high temperatures during production or molding of polyester.

Next, the method for surface treatment of particles in the present invention will be explained. As the surface treatment agent, it is necessary to use a copolymer containing a vinyl compound unit having a benzene ring in the side chain and an acrylic acid derivative unit.

Examples of the vinyl compound having a benzene ring in a side chain include, but are not limited to, styrene, divinylbenzene, and stilbene.

Note that the benzene ring is a halogen atom or an alkyl group.

It may be substituted with a hydroxyl group or the like. Styrene is particularly preferably used in the present invention.

Also, as an acrylic acid derivative, acrylic acid.

Examples include methacrylic acid, metal salts of these acids, and ammonium salt 7 esters. Among these, metal salts and ammonium salts are particularly preferably used in the present invention.

Add the copolymer containing these units to a slurry of crosslinked polymer particles such as water or ethylene glycol, and thoroughly disperse and mix with a stirring dispersion bag W (homomixer, homogenizer, etc.), or add the copolymer. Thereafter, the crosslinked polymer particles can be surface-treated by performing a wet pulverization treatment.

There is no particular restriction on the amount of the surface treatment agent added, but it is preferably 0.1 to 5% by weight based on 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, the treatment agent itself will aggregate, 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 the pulverization
Treatments such as classification 5 filtration are performed.

If the average particle diameter is less than 0.01 μm, the slipperiness and abrasion resistance when formed into a film are insufficient, and if it exceeds 5 μm, the surface roughness of the film becomes excessive, which is not preferable.

The amount of the surface-treated crosslinked polymer obtained as described above added in the polyester composition is 0°001 to 10
Must be within the range of % by weight.

If the amount added is less than 0.001% by weight, the slipperiness and abrasion resistance will be insufficient when formed into a film. Also, the amount added is 1
If it exceeds 0% by weight, the surface roughness of the film will become excessive, which is not preferable.

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

The polyester composition of the present invention contains titanium dioxide and silica in addition to surface-treated crosslinked polymer particles.

Fine particles of kaolin, calcium carbonate, etc. may be used in combination.

In addition to such fine particles, internal particles precipitated by a reaction between a catalyst residue and a phosphorus compound in a polyester polycondensation reaction system can also be used.

The polyester composition of the present invention further needs to have a specific resistance during melting of 1×10 6 to 1×10 9 Ω・ctn, and in particular, a range of 3×10 6 to 5×10″ Ω・0 is desirable. Ratio If the resistance is less than 10 6 Ω·Cl 11 , the thermal stability of the polymer deteriorates, making it difficult to form a film.

On the other hand, if the specific resistance exceeds lXl0'Ω·, the film forming rate will increase even if the electrostatic cooling method (an excellent manufacturing method for unstretched sheets described in Japanese Patent Publication No. 37-6142, etc.) is used. It becomes difficult to raise the temperature, and the productivity of the film becomes extremely poor. The specific resistance of this melting degree is adjusted by solubilizing a metal compound in polyester, and usually after the completion of the transesterification reaction, the specific resistance of the transesterification reaction catalyst, such as a magnesium compound, a lithium compound, etc., is 0.3%.
This is carried out by adding 1.0 to 1.0 times the equivalent, preferably 0.4 to 0.8 times the equivalent of the phosphorus compound.

The polyester composition of the present invention is melt-extruded, turned into an unstretched sheet on a rotating cooling drum (preferably in combination with the above-mentioned electrostatic application cooling method), and heated for 2 to 10 minutes in the machine direction at 80 to 130°C.
Stretched 2 to 10 times in the transverse direction at 80 to 140°C, one after another or simultaneously, stretched again if necessary, and then stretched to 160 to 140°C.
Although it can be formed into a film by heat treatment at 240°C, the method is not limited to this, and the film forming conditions are appropriately selected depending on the use of the film.

〔Example〕

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

A method for evaluating physical properties and characteristics in the present invention is shown below.

(1) Average particle size of crosslinked polymer particles The particle size was measured by centrifugal sedimentation using Shimabara Seisakusho 5A-CP3.

(2) Sliding property of the film Sliding property was evaluated by measuring the coefficient of friction according to the method of ASTM D1891-63.

(3) Abrasion resistance of the film The abrasion resistance was evaluated using the running system shown in Figure 1.
The test piece was run over a length of 1,000 m, and the amount of adhesion due to abrasion on the 6 mmφ pin (SUS420J2 surface finish 0.23) indicated by 1 was visually evaluated and expressed in the following ranking.

The running speed of the film is 10 m/mjn, the tension is approximately 500 g, and the angle (θ) of the wrapping around the pin is 135°.
And so.

O... There is almost no adhesion.

△... Slight adhesion.

×...The amount of adhesion is large.

(4) Number of coarse protrusions Aluminum was deposited on the film surface and measured using a three-beam interference microscope. The number of n-th order interference fringes at a measurement wavelength of 0.54 μn is shown in terms of number per 25c+fl.

The number of protrusions of 4th or higher order is indicated as F4. The number of protrusions of 3rd or higher order is indicated as F.

(5) Surface roughness (Ra) Measured by the method described in JIS BO601-1976.

For measurement, a surface roughness measuring machine model 5E-3 manufactured by Koita Research Institute was used.
F was used, the stylus diameter was 2 μ, the stylus load was 30 mg, and the cutoff value was 0.08 mn+.

(6) Affinity between additive particles and polyester To evaluate the affinity between additive particles and polyester, the size of voids around the particles inside the film was observed using a polarizing microscope.
The ranking is shown below.

O... No voids are observed in the majority of particles.

Δ...The number of particles with voids is slightly higher.

×...Extremely large voids are seen in the majority of particles.

(7) Film internal haze It was measured by coating both sides of the film with liquid paraffin using a turbidimeter NDH-2A manufactured by Nippon Heavy Industries Ltd. according to the method of ASTM D1003-61.

(8) Resistivity of polyester when melted Prtinsch Journal of Applied Physics (Brit, J., Appl, Phys.)
17, pp. 1149-1154 (1966). However, in this case, the temperature at the time of melting of the polymer composition was 290°C, and the value immediately after applying a direct current of 3000 V was taken as the specific resistance at the time of melting.

In addition, in the examples, "1 part" or "c%" means "unless otherwise specified".
"parts by weight" or "% by weight".

Example 1 [Synthesis of crosslinked polymer particles] A homogeneous solution of 100 parts of methyl methacrylate, 25 parts of divinylbenzene, 22 parts of ethylvinylbenzene, 1 part of benzoyl a oxide, and 100 parts of toluene was dispersed in 700 parts of water.

Next, polymerization was carried out under a nitrogen atmosphere at 80°C with stirring for 4 hours. The average particle size of the obtained crosslinked polymer particles having ester groups was about 10 μm. The resulting 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 at a concentration of 1.0%, and then ground using a sand grinder to form a particle slurry with an average particle size of 1.2 μm. I got it. This slurry was subjected to wet classification and filtration to obtain a slurry having a concentration of 20 parts and an average particle size of 1.0 μm.

[Manufacture of polyester composition] 100 parts of dimethylene 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 from the start of the reaction to raise the temperature to 230°C, and the transesterification reaction was substantially completed. Next, after adding 0.04 part of ethyl acid phosphate (at this time, 0.7 times equivalent amount of phosphorus compound to the magnesium compound is added), the above particle ethylene glycol having an average particle size of 1.0 μm is added. (If 1.5 parts of slurry is added, the particles will be contained in an amount of 0.3% based on the resulting polyester resin) Furthermore, 0.04 parts of antimony trioxide is added and polycondensation is carried out for 4 hours to obtain a polyethylene terephthalate polymer. Ta. The specific resistance of the resulting polymer when melted was 5×10 bΩ·.

[Manufacture of film] The obtained polymer was heated and dried at 180°C for 6 hours in a nitrogen atmosphere, then melt-extruded using an extruder, and a 220 μm sheet was created using an electrostatic cooling method. After stretching 3.7 times at 90°C and 4 times in the transverse direction at 90°C, heat treatment was performed at 220°C for 5 seconds to obtain a biaxially stretched polyethylene terephthalate film with a thickness of 15 μm.

In addition, at this time, the speed at which a film can be formed without trapped air bubbles using the electrostatic application cooling method, that is, the maximum rotational speed of the cooling drum is 6.
It was possible to achieve a high speed of 0 m/min, and the productivity of the film was good.

Example 2 A polyester composition was obtained in the same manner as in Example 1 except that the amount of surface treatment agent was 2% based on the particles and the average particle size of the particles added was 0.3 μm. A film with a thickness of 15 μm was obtained in the same manner as above.

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, no surface treatment agent was added, and no surface treatment was performed. A film with a thickness of 15 μm was obtained in the same manner.

Comparative Example 2 A polyester composition was obtained in the same manner as in Example 1, except that the amount of crosslinked polymer particles added was 0.0005% by weight, and a film was formed in the same manner as in Example 1. A film with a thickness of 15 μm was obtained.

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

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

The specific resistance of the obtained composition when melted was as high as 5×10 9 Ω·mark. Next, a biaxially stretched film was produced in the same manner as in Example 1, but the speed at which the film could be formed without trapped air bubbles, that is, cooling The maximum rotation speed of the drum was slow at 20 m/min, and the productivity of the film was poor.

The results obtained above are summarized in Table 1.

〔Effect 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 extremely improved dispersibility of the particles. A film made using such a polyester composition has extremely few particles falling off, excellent abrasion resistance, high transparency due to few internal voids, and extremely few rough protrusions on the surface.

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

[Brief explanation of drawings]

Figure 1 is a schematic diagram of the running system for evaluating the abrasion resistance of the film.
, 2S surface finish fixing pin, (IT) is tension link up. Further, the angle θ of the winding of the film around the fixed bottle is 135°.

Claims (1)

[Claims] (1) A particle with an average particle size of 0.5 mm obtained by surface treating particles made of a crosslinked polymer with a copolymer containing a vinyl compound unit having a benzene ring in the side chain and an acrylic acid derivative unit.
Contains 0.001 to 10% by weight of particles of 01 to 5 μm,
And the specific resistance value when melted is 1.0 x 10^6 ~ 1.0 x 1
A polyester composition characterized by having a resistance of 0^9Ω·cm.