JP3148351B2 - Polyethylene naphthalate composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyethylene naphthalate composition, and more particularly, to an improved melt moldability.
The present invention relates to a polyethylene naphthalate molded article excellent in slipperiness, abrasion resistance, transparency, etc., and particularly to a polyethylene naphthalate composition useful for molding films, fibers and the like.

[0002]

2. Description of the Related Art Polyethylene naphthalate is widely used for films, fibers and the like because of its excellent mechanical and chemical properties. However, when producing films or fibers that make full use of their transparency and brilliancy, process defects often occur in the molding and processing steps. The cause is often due to a high coefficient of friction.

Hitherto, as a method of lowering the friction coefficient of polyester, many methods have been proposed in which inert particles are present in polyester, but the affinity between the particles and polyester is not sufficient, and films and fibers Neither slip nor abrasion resistance were satisfactory. This method will be described more specifically. As a means for improving the surface characteristics of polyester, a method of depositing part or all of a catalyst or the like used in polyester synthesis in a reaction step (internal particle deposition method) Many methods of adding particles such as calcium and silicon oxide during or after polymerization (external particle addition method) have been proposed.

[0004] However, the internal particle precipitation method is as follows.
Since the particles are a metal salt of the polyester component, etc., the affinity with the polyester is good to some extent, but since it is a method of generating particles during the reaction, control of the particle amount, particle diameter and prevention of generation of coarse particles, etc. Is difficult.

[0005] On the other hand, in the external particle addition method, if the particle size and the amount of addition are appropriately selected, and if the particles obtained by removing the coarse particles by classification or the like are added, the lubricity will be excellent.

However, when silica fine particles are used, particularly in polyethylene naphthalate, the crystallization speed is increased, the crystallization energy is increased, and as a result, the melting energy at the time of melting the polymer is significantly increased, and the polymer is hardly melted. Would.

When such a polymer is melt-extruded and formed into a film or fiber, unmelted polymer tends to remain, for example, becomes coarse particles in the film, resulting in poor transparency and abrasion resistance. Problem arises.

[0008]

DISCLOSURE OF THE INVENTION In view of the above-mentioned circumstances, the present inventors diligently seek to obtain a polyethylene naphthalate composition suitable for molding a molded article excellent in transparency, slipperiness or abrasion resistance. As a result of the investigation, they have found that a polyethylene naphthalate composition containing a specific amount of silica fine particles and copolymerizing a specific ratio of diethylene glycol has excellent properties, and has reached the present invention.

Accordingly, it is an object of the present invention to provide a molded article excellent in transparency, slipperiness, and abrasion resistance, particularly a polyethylene naphthalate composition capable of forming a film.

[0010]

That is, the present invention provides a method for preparing silica fine particles having an average particle size of 0.05 to 0.2 μm by 0.3 to 0.3 μm.
5% by weight, and 0.8 to 0.8% of diethylene glycol
This is achieved by a polyethylene naphthalate composition copolymerized at 2% by weight.

The polyethylene naphthalate in the present invention is a polyester containing naphthalenedicarboxylic acid as a main acid component and ethylene glycol as a main glycol component, and a diethylene glycol as a part of the glycol component. Of these, polyethylene naphthalate in which 80 mol% or more of the total acid component is 2,6-naphthalenedicarboxylic acid and 80 mol% or more of the total glycol component is ethylene glycol is preferred.

Up to 20 mol% of the total acid component of the polyethylene naphthalate can be an aromatic dicarboxylic acid other than 2,6-naphthalenedicarboxylic acid, an aliphatic dicarboxylic acid, an alicyclic dicarboxylic acid and the like. As the aromatic dicarboxylic acid, for example, terephthalic acid, isophthalic acid,
Biphenylethane dicarboxylic acid, biphenyl dicarboxylic acid, biphenyl ether dicarboxylic acid, biphenyl sulfone dicarboxylic acid, biphenyl ketone dicarboxylic acid, anthracene dicarboxylic acid and the like can be mentioned. Examples of the aliphatic dicarboxylic acid include adipic acid and sebacic acid. Examples of the alicyclic dicarboxylic acid include cyclohexane-1,4-dicarboxylic acid.

Further, 20 mol% or less of the total glycol component of polyethylene naphthalate can be aliphatic glycol other than ethylene glycol, aromatic diol, aliphatic diol having an aromatic ring, polyalkylene glycol and the like. Examples of the aliphatic glycol include trimethylene glycol, tetramethylene glycol, pentamethylene glycol, hexamethylene glycol,
Examples thereof include polymethylene glycol having 3 to 10 carbon atoms such as decamethylene glycol and alicyclic glycol such as cyclohexanedimethanol. Examples of the aromatic diol include hydroquinone, resorcin, 2,2-bis (4-hydroxyphenyl) propane, and the like. Examples of the aliphatic diol having an aromatic ring include 1,4-dihydroxymethylbenzene. Examples of the polyalkylene glycol include polyethylene glycol, polypropylene glycol, polytetramethylene glycol, and the like.

Further, the amount of diethylene glycol which constitutes a part of the glycol component of polyethylene naphthalate is 0.1 to the weight of polyethylene naphthalate.
It is 8 to 2% by weight, preferably 1 to 2% by weight. When the amount of diethylene glycol is less than 0.8% by weight,
Since the crystallization of the polymer is not suppressed and the melting energy is increased, the unmelted polymer remains during the film forming, and coarse projections are formed on the film surface, which is not preferable. On the other hand, if the content exceeds 2% by weight, the strength after film formation, for example, the Young's modulus, decreases, and the durability becomes poor.

The polyethylene naphthalate used in the present invention includes a component derived from an oxycarboxylic acid such as an aromatic oxyacid such as hydroxybenzoic acid; an aliphatic oxyacid such as ω-hydroxycaproic acid, and a dicarboxylic acid component. And those which are copolymerized or bonded at 20 mol% or less based on the total amount of the oxycarboxylic acid component are also included.

Further, in the polyethylene naphthalate of the present invention, a tricarboxylic or polyfunctional polycarboxylic acid or polyhydroxy compound, for example, in an amount in a substantially linear range, for example, 2 mol% or less based on the total acid components, for example, Copolymers of trimellitic acid, pentaerythritol and the like are also included.

Furthermore, additives such as pigments, dyes, ultraviolet absorbers, heat stabilizers, light stabilizers, antioxidants, light-shielding agents (eg, carbon black, titanium dioxide, etc.) are added to the polyethylene naphthalate in the present invention. Can be contained as necessary.

In the present invention, the silica fine particles dispersed and contained in polyethylene naphthalate are not particularly limited by the kind and the production method. For example, a dry method or a wet method (a method of removing alkali from sodium silicate, a method of hydrolyzing an alkoxysilane). Decomposition / condensation method).

The fine silica particles may contain 30% or less of aluminum.

The shape of the silica fine particles is not particularly limited, but is preferably as spherical as possible.

The spherical particles are defined by the following volume shape factor φ.

[0022]

(Equation 1)

It is preferable that φ is in the range of 0.30 to π / 6. Also, as φt of the whole particle group,
It is represented by the number average of φ of each particle, and φt is 0.40 to π / 6.
It is preferred that

Further, the relative standard deviation defined below of the spherical particles is preferably 0.7 or less, more preferably 0.5 or less.

[0025]

(Equation 2)

The average particle size of the silica fine particles is 0.05 to 0.1.
2 μm, and preferably 0.05 to 0.15 μm. If the average particle size is smaller than 0.05 μm, the effect of improving the slipperiness and the abrasion resistance is insufficient, which is not preferable. On the other hand, if it is larger than 0.2 μm, the abrasion resistance tends to deteriorate, which is not preferable.

Thus, the average particle size means the "equivalent spherical diameter" of the particle at a point of 50% by weight of all the measured particles. The “equivalent spherical diameter” means the diameter of an imaginary sphere having the same volume as the particle, but when a true spherical particle is used, it becomes the weight average of the diameter. The average particle size can be calculated from an electron micrograph of the particles or measurement by a usual sedimentation method.

The content of the silica fine particles is 0.3 to 5% by weight.
Is preferred. If the content is less than 0.3% by weight, the effect of improving the abrasion resistance is insufficient, which is not preferable. 5
If the amount is more than the weight percentage, coarse projections may be generated on the film surface due to aggregation, which is not preferable.

The silica fine particles are preferably subjected to a purification process to remove coarse particles before being contained in polyethylene naphthalate. As a classification means, for example, a wet or dry centrifugal separator, filter filtration and the like can be mentioned. These means may be used in combination of two or more, and may be purified stepwise.

The silica fine particles may be contained in polyethylene naphthalate at any time and by any method.
A preferred method is to add the powder to the molten polymer after polymerization by using a screw-type twin-screw kneading extruder or a Banbury mixer and kneading. Of course, as a general method, a method may be used in which the compound is added as a glycol slurry before the polymerization reaction during the production of polyethylene naphthalate, particularly before the end of the transesterification or esterification reaction.

Polyester molded articles, for example, fibers and films, are obtained by directly using the above-mentioned polyethylene naphthalate composition.
Alternatively, it can be obtained by diluting with another polyethylene naphthalate (polyethylene naphthalate not containing silica fine particles at a predetermined ratio) and forming a yarn, forming a film, or the like. As other polyethylene naphthalate used for dilution, for example, polyethylene naphthalate containing particles or polyethylene naphthalate containing no particles produced by a conventional precipitation method or addition method can be mentioned.
In any case, it is necessary that the finally obtained polyester molded product contains a predetermined amount of silica fine particles.

The polyethylene naphthalate composition of the present invention can be formed into a molded product such as a film or a fiber by a known method.

In the case of a film, the film is formed by a known method, for example, melt extrusion at a temperature of 280 to 300 ° C. into a sheet, and quenching and solidification to form an amorphous sheet. A method of successively biaxially stretching in the longitudinal direction, a method of simultaneously biaxially stretching in the longitudinal and transverse directions, and the like can be employed.

In the case of fibers, the yarn is formed by a known method, for example, melt extrusion at a temperature of 280 to 300 ° C.
After spinning at a speed of / min, for example, drawing or false twisting,
Alternatively, a heat treatment method or the like can be adopted.

The polyethylene naphthalate composition of the present invention suppresses an increase in crystallization energy due to silica fine particles and prevents the formation of an unmelted polymer during melt molding, and has transparency, slipperiness, A molded product excellent in abrasion resistance, abrasion resistance and the like can be formed and can be used for various purposes. In particular, it can be preferably used in the film field and the fiber field, which require slipperiness, abrasion resistance, abrasion resistance, and transparency.

[0036]

The present invention will be further described with reference to the following examples. In the examples, “parts” means parts by weight. The measurement of each characteristic value in the examples was performed according to the following method.

(1) Average particle size of particles The particle size distribution is determined by the sedimentation method, and is indicated by the “equivalent spherical diameter” of the particles at a point of 50% by weight of all the particles.

(2) Sharpness The sharpness of the running surface of the film is evaluated using a five-stage mini super calendar. The calender is a five-stage calender of a nylon roll and a steel roll. The processing temperature is 80 ° C., the linear pressure applied to the film is 200 kg / cm, and the film speed is 50 m / min. The running film is evaluated for the sharpness of the film by the dirt adhering to the top roller of the calendar when the running film runs for a total length of 6000 m. <4-stage judgment> ◎ Nylon roll dirt completely ○ Nylon roll dirt almost × Nylon roll gets dirty XX Nylon roll gets very dirty

(3) Haze (degree of haze) The haze of the film is determined by an integrating sphere HTR meter manufactured by Nippon Seimitsu Optical Co., Ltd. in accordance with JIS-K674.

(4) After drying the dispersible polyester at 180 ° C., it is formed into a sheet by an extruder.
The film was biaxially stretched to 3.5 times in longitudinal stretching and 4.0 times in transverse stretching, and then heat-fixed to form a film having a thickness of 15 μm. The film is observed with a microscope under polarized light, and the following judgment is made using fish having foreign matter (scale) particles at the place where the polarized light is applied as fish eyes. Special grade: 5 fish eyes / less than 50 cm ² First grade: 6-1 fish eyes
0 / 50cm ² Class 2: Fish Eye 10-20 / 50cm ² Class 3: Fish Eye 20 / 50cm ²
In addition, the first grade or higher is put to practical use.

Examples 1 to 5 100 parts of dimethyl-2,6-naphthalate and 70 parts of ethylene glycol (hereinafter abbreviated as EG) were esterified according to a conventional method using 0.035 part of manganese acetate tetrahydrate as a catalyst. After the exchange reaction, 0.03 part of trimethyl phosphate was added, and silica fine particles having an average particle diameter shown in Table 1 were further added with stirring as an EG slurry so as to have a concentration shown in Table 1. Further, diethylene glycol was added to the amount shown in Table 1. Thereafter, 0.03 part of antimony trioxide was added, and a polycondensation reaction was carried out in a usual manner under a high temperature and high vacuum to obtain a modified polyethylene-2,6 having an intrinsic viscosity (orthochlorophenol, 35 ° C) of 0.60 dl / g. -Naphthalate was obtained.

Next, the resulting modified polyethylene-2,
After drying 6-naphthalate at 180 ° C, it is formed into a sheet by a melt extruder, and subsequently at 120 ° C, a longitudinal stretching ratio of 3.5 times,
The film was biaxially stretched to a transverse stretching ratio of 4.0 and then heat-fixed to form a film having a thickness of 15 μm. Table 1 shows the characteristics of this film. Both the dispersibility and the scraping property of the obtained film were good.

Comparative Example 1 A film containing 0.8% by weight (based on polymer) of spherical silica having an average particle diameter of 0.1 μm was obtained in the same manner as in Example 1. However, the co-weight of diethylene glycol is set to 0.1.
5% by weight (based on polymer).

As a result, many unmelted materials were found in the film, and satisfactory results were not obtained in both dispersibility and scraping properties.

[Comparative Examples 2 and 3] A film to which spherical silica having an average particle diameter of 0.04 µm (Comparative Example 2) or 0.23 µm (Comparative Example 3) was added was obtained in the same manner as in Example 1. However, the co-weight of diethylene glycol was changed as shown in Table 1.

When the average particle size of the spherical silica was 0.04 μm, the particle size was too small, and in the evaluation of the abrasion property, the portion of the background other than the projections due to the particles on the film surface was shaved, and was rejected. On the other hand, when the average particle size of the spherical silica is 0.23 μm,
The particle size was too large, the protruding portion due to the particles dropped off, and the result was inferior abrasion.

Comparative Example 4 A film containing 6.0% by weight (based on polymer) of spherical silica having an average particle diameter of 0.1 μm was obtained in the same manner as in Example 5.

When this film was evaluated, it was found that particles were agglomerated and the shaving property was poor.

Comparative Example 5 A film containing 0.8% by weight (based on polymer) of spherical silica having an average particle diameter of 0.1 μm was obtained in the same manner as in Example 1. However, the diethylene glycol content was 2.3% by weight.

A film having reduced Young's modulus and heat resistance was obtained and could not be produced.

[0051]

[Table 1]

The silica fine particles in the table were prepared by the following method.
Was prepared. (A) Spherical silica fine particles having an average particle size of 0.1 μm These fine particles are described in JP-A-63-64911.
It was prepared according to the method described. That is, the catalyst chemical industry
Oscar 1725 (Average particle size = 45 mμ, spherical)
Silica) as a seed solution raw material, and sodium silicate
Solution (SiO2 concentration 20% by weight) and pure water
A seed solution is prepared, and the seed solution is supplied to a reflux device, a stirrer, and a heating device.
10 liter stainless steel container equipped with a heating device
And the temperature is raised to a predetermined temperature as shown in Table 2,
While maintaining the temperature, add the acidic silicic acid solution at a constant rate.
In addition, build-up for growing the particle diameter was performed.
After completion of the addition, the mixture is kept at the same temperature for about 1 hour, and then cooled,
Condensed to a specified concentration by an ultrafiltration device and shown in Table 2.
Such fine silica particles (silica sol liquid) were obtained. Acid ke
For the acid solution, dilute a commercially available sodium silicate solution with pure water,
This is passed through a column filled with hydrogen-type cation exchange resin.
Thus, it was prepared by dealkalization. (B) Spherical silica fine particles having an average particle size of 0.05 μm
6.8 by the method described in Example 4 of JP-A-63-45114.
mμ spherical particles are prepared, and the resulting particles are
Other than changing the build-up conditions as shown in Table 2
Is to prepare spherical silica fine particles in the same manner as in (a) above.
Was. (C) Catalyst formation of spherical silica fine particles having an average particle size of 0.2 μm
Oscar 1727 manufactured by Kogyo Co., Ltd. (Average particle size = 120 m
μ, spherical silica) as a raw material for the seed solution.
Except for changing the build-up conditions as described above,
In the same manner as described above, silica fine particles were prepared. (D) Lumpy silica fine particles having an average particle diameter of 0.1 μm
Change the build-up conditions as shown in Table 2.
Except for the above, silica fine particles were prepared in the same manner as in (a) above.
Was. (E) Spherical silica fine particle seed having an average particle size of 0.04 μm
Change the conditions for building up liquid particles as shown in Table 2.
Except for the above , spherical silica fine particles were prepared in the same manner as in the above (b). (F) Spherical silica fine particles having an average particle diameter of 0.23 μm Oscar 1727 manufactured by Kasei Kogyo Co., Ltd. (average particle diameter = 1
20mμ, spherical silica) as a raw material for the seed liquid,
Except for changing the build-up conditions as shown in Table 2,
Silica fine particles were prepared in the same manner as in (a).

[0053]

[Table 2]

[0054]

According to the present invention, by appropriately containing diethylene glycol, transparency, slipperiness and shaving can be obtained without generating unmelted matter in polyethylene naphthalate caused by inclusion of silica particles. The present invention can provide a polyethylene naphthalate composition suitable for molding a molded article having excellent properties and the like.

Continuation of front page (58) Field surveyed (Int.Cl. ⁷ , DB name) C08L 67/00-67/02

Claims (2)

(57) [Claims] 1. A polyethylene naphthalate composition containing 0.3 to 5% by weight of silica fine particles having an average particle size of 0.05 to 0.2 μm and copolymerizing 0.8 to 2% by weight of diethylene glycol. 2. The polyethylene naphthalate composition according to claim 1, wherein the silica fine particles are monodispersed spherical silica fine particles.