JPH08302165A - Antistatic polyester film - Google Patents

Abstract

PURPOSE: To obtain a polyester film excellent in antistatic properties. CONSTITUTION: This film is formed from a polyester resin produced by reacting a dicarboxylic acid component mainly comprising an arom. dicarboxylic acid or its ester-forming deriv. with a diol component mainly comprising ethylene glycol and contains 0.01-5wt.% compd. represented by the general formula: RfSO3 M (wherein Rf is a 3-10C perfluoroalkyl group; and M is an alkali metal).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antistatic polyester film, and more particularly, it has antistatic properties and excellent properties such as mechanical properties, heat resistance, light transmittance, surface gloss and chemical resistance. The present invention relates to a polyester film which is useful as various packaging materials and general industrial materials.

[0002]

2. Description of the Related Art Polyester films containing polyethylene terephthalate as a main component have excellent properties such as mechanical properties, chemical resistance, gas barrier properties, transparency and safety. It is applied to many uses such as recording media use, plate making use, photosensitive etching use, electrical use, and packaging use.

However, the polyester film is
Since the friction coefficient and the specific electric resistance are high, there is a problem in that it is easily charged by static electricity. The electrification of the polyester film causes disadvantages such as squeezing between films and winding around a roll in the film forming step and the slitting step, and this electrification is also preferable in terms of safety such as discharge spark to a device or an operator. is not.

Further, since the charged polyester adheres dust, the dust adheres to the film surface in the printing process and the magnetic band application process, and the adhesion causes a beard to occur, which makes the printed matter good in appearance. It is a cause that it is difficult to manufacture a recording body having good recording characteristics.

As an attempt to prevent electrostatic charging of a polyester film, many techniques have been developed, such as a method of coating an antistatic agent on the film surface and a method of simultaneously extruding a resin having an antistatic effect and a polyester resin. By the method described above, a polyester film having a satisfactory antistatic effect can be obtained.
However, it is difficult to say that these methods are industrially and economically effective because they increase the cost because the film production efficiency is low.

On the other hand, as a method for modifying the polyester resin itself to impart an antistatic ability, for example, Japanese Patent Publication No. 58-
No. 12910 discloses a method of imparting antistatic ability by mixing polyethylene glycol and a sulfonic acid metal salt derivative into polyester, and Japanese Patent Publication No. 63-3895 discloses that polyester has polyethylene glycol and alkyl sulfonic acid. A method for obtaining an antistatic polyester film by adding and mixing the alkali metal salt and the insoluble particles is disclosed.

However, although these methods have some antistatic effect, they are not sufficiently effective as compared with the conventional methods such as the coating method. Furthermore, when a film is actually formed using such a modified resin, the polyester film obtained is oxidatively decomposed or thermally decomposed in the polyalkylene glycol in the drying / melting step of the polyester resin. Mechanical strength of the polyester film is reduced, and the antistatic agent bleeds out on the surface of the polyester film, and the haze of the polyester film is further increased, impairing the excellent properties of the polyester film. There was a drawback. Further, in polyesters to which polyalkylene glycol is added, film breakage frequently occurs due to thermal decomposition of polyalkylene glycol in the polyester composition in the film forming process, and an antistatic agent having good stability has been demanded.

[0008]

The present inventors have arrived at the present invention as a result of earnestly examining the charging property of a polyester film in view of such a situation.

That is, the present invention is a film made of a polyester resin containing a dicarboxylic acid component containing an aromatic dicarboxylic acid or an ester-forming derivative thereof as a main component and a diol component containing ethylene glycol as a main component as constituent components. In the film, the following general formula (I)
The antistatic polyester film is characterized by comprising 0.01 to 5% by weight of the compound represented by.

RfSO ₃ M (I) (In the formula, Rf represents a perfluoroalkyl group having 3 to 10 carbon atoms, and M represents an alkali metal.)

The polyester film of the present invention comprises a polyester film made of the polyester resin having the above-mentioned constitution and containing the compound represented by the general formula (I), that is, an alkali metal salt of perfluoroalkylsulfonic acid. Therefore, the polyester film of the present invention,
It is possible to bring about excellent antistatic property without lowering the thermal stability of the film.

Specific examples of the alkali metal salt of perfluoroalkyl sulfonic acid represented by the above general formula (I) used in the present invention include sodium perfluoropropyl sulfonate, lithium perfluoropropyl sulfonate, and perfluorobutyl sulfonic acid. Potassium, sodium perfluorobutyl sulfonate, lithium perfluorohexyl sulfonate, sodium perfluorohexyl sulfonate, potassium perfluorohexyl sulfonate, lithium perfluorooctyl sulfonate,
Examples thereof include potassium perfluorooctyl sulfonate, sodium perfluorodecyl sulfonate, potassium perfluorodecyl sulfonate, and the like.

In the above general formula (I), when the carbon number of the perfluoroalkyl group is less than 3, the surface activity is small and the antistatic property is not exerted. On the other hand, when it exceeds 10, it is combined with the polyester resin. The compatibility becomes poor and the transparency of the film decreases.

The content of the alkali metal salt of perfluoroalkylsulfonic acid in the polyester film is 0.01.
To 5% by weight, preferably 0.05 to 5% by weight, and if less than 0.01% by weight, there is no antistatic effect.
On the other hand, if the amount exceeds 5% by weight, the characteristics of the film are deteriorated such as whitening of the film.

The polyester resin used to obtain the antistatic polyester film of the present invention comprises a dicarboxylic acid component containing an aromatic dicarboxylic acid or its ester-forming derivative as a main component, and a diol component containing ethylene glycol as a main component. It is composed of

Examples of the aromatic dicarboxylic acid or its ester-forming derivative include terephthalic acid, isophthalic acid, naphthalene-1,4 or 2,6-dicarboxylic acid and its alkyl ester, aryl ester and the like.

The aromatic dicarboxylic acid or its ester-forming derivative in the polyester resin is preferably contained in the total dicarboxylic acid component in an amount of 80 mol% or more, more preferably 85 mol% or more. This is because if the aromatic dicarboxylic acid component is less than 80 mol%, the mechanical strength of the film may decrease and the film-forming stability will also decrease.

Further, in the present invention, as a dicarboxylic acid component other than the above aromatic dicarboxylic acid or its ester-forming derivative, an aliphatic dicarboxylic acid or its ester-forming derivative is contained in an amount of 20 mol% or less in all dicarboxylic acid components,
It may be contained in a range of preferably 15 mol% or less. This is because if it exceeds 20 mol%, the mechanical strength of the film may be lowered.

Examples of the aliphatic dicarboxylic acid or its ester-forming derivative used in the present invention include oxalic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, sebacic acid, azelaic acid and their alkyl or aryl esters. Is mentioned.

The diol component is mainly composed of ethylene glycol. It is necessary that the content of ethylene glycol in all diol components is 50 mol% or more, and preferably 70 mol% or more. This is because when the content of ethylene glycol is less than 50 mol%, the polymerization reactivity is lowered in the resin production stage, which makes it difficult to obtain a resin having a desired degree of polymerization. This is because.

Other diol components which can be used in combination with ethylene glycol include, for example, propylene glycol, butanediol, neopentyl glycol, cyclohexanedimethanol, diethylene glycol, triethylene glycol, and ethylene oxide adducts of bisphenol compounds or their derivatives. Can be mentioned.
These can be used alone or in combination of two or more, and the use is 0 to
It is in the range of 50 mol%.

The ethylene oxide adduct of a bisphenol compound or its derivative is represented by the following general formula (II)
And those represented by (III).

[0023]

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[0024]

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Among these, it is preferable to use an ethylene oxide adduct of bisphenol A having a structure represented by the following general formula (IV).

[0026]

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In addition, it is preferable to contain polyethylene glycol and / or polyoxytetramethylene glycol as a diol component from the viewpoint of crystallinity control. The polyethylene glycol or polyoxytetramethylene glycol is preferably 0.5
Is in the range of up to 5% by weight.

The polyethylene glycol usable in the present invention preferably has an average molecular weight of 300 to 20,000, more preferably 1,000 to 20,000. The polyoxytetramethylene glycol has an average molecular weight of 300 to 4000, more preferably 500 to 3000.

Further, in the present invention, trivalent or higher polyvalent carboxylic acid and / or polyhydric alcohol is added in an amount of 0.01 to 1 with respect to each of the dicarboxylic acid component and the diol component.
It can be used in the range of mol%. If the amount used is less than 0.01 mol%, the compounding effect cannot be obtained, while 1
If it exceeds mol%, gelation will occur during the polymerization.

Examples of polycarboxylic acids used are:
Examples thereof include trimellitic acid, pyromellitic acid, and anhydrides thereof, and examples of the polyhydric alcohol include trimethylolpropane, pentaerythritol, and glycerin.

These polyester resins can be produced by a known direct polymerization method or transesterification method,
The degree of polymerization is not particularly limited, but the intrinsic viscosity [η] (measured at 25 ° C. in a solution of a mixture of phenol / tetrachloroethane and the like by weight) is determined from the moldability of the raw film.
Is preferably about 0.5 to 1.2 dl / g.

The method for producing the polyester film of the present invention is not particularly limited, but for example, the polyester film is formed by the following method. First, a polyester resin containing a perfluoroalkyl sulfonic acid alkali metal salt represented by the above general formula (I) is produced by a melt mixing method, etc., dried, then melted, extruded from a die, and cast method. Alternatively, a raw film is formed by a calendar method or the like. Then, this raw film is heated at a temperature higher than the glass transition temperature (Tg) of the polyester resin by 3 ° C. or more, preferably 5 ° C. or more in the longitudinal direction or the transverse direction by 1.5 to 5.0 times, preferably 1 .0 to
Stretch 4.8 times. Further, if necessary, 1.0 to 1.8, preferably 1.0 to 1.
Stretch 5 times. This is effective for improving the mechanical strength of the film.

The film is stretched by simultaneous biaxial stretching and sequential 2
It is carried out by a method such as axial stretching or uniaxial stretching, and either longitudinal stretching or lateral stretching may be performed first. The stretched polyester film can be used as a product as it is, but it is 50 ° C from the viewpoint of dimensional stability.
You may perform heat processing for several seconds to several tens of seconds at the temperature of -150 degreeC.

The thickness of the polyester film of the present invention is
Although not particularly limited, those having a range of 1 to 600 μm are practically used. For packaging purposes, particularly packaging of foods, beverages, pharmaceuticals, etc., those having a range of 6 to 380 μm are used. For PET bottles, polyethylene bottles, and glass bottle labels, those in the range of 20 to 70 μm are used.

The polyester film of the present invention comprises 20
C, 50% R.C. Half-life based on the charged voltage when measured with a static Honest meter under H is 1
It is necessary to be within 80 seconds, preferably 150
Within seconds. This is because if the half-life is longer than 180 seconds, there is no effect in preventing the occurrence of whiskers during printing.

The polyester film of the present invention may be subjected to various conventionally known processing treatments or may be blended with suitable additives in order to impart more specific performance. Examples of processing treatments include irradiation with ultraviolet rays, α rays, β rays, γ rays or electron rays, corona treatment, plasma irradiation treatment, flame treatment and the like, resins such as polyvinylidene chloride, polyvinyl alcohol, polyamide and polyolefin. Coating, laminating, vapor deposition of metal, and the like. Examples of additives include polyamide, polyolefin, polymethylmethacrylate, resins such as polycarbonate, silica, talc, kaolin, inorganic particles such as calcium carbonate,
Examples thereof include pigments such as titanium oxide and carbon black, ultraviolet absorbers, release agents, antistatic agents, flame retardants and the like.

[0037]

EXAMPLES The present invention will be described in more detail below with reference to examples and comparative examples. The evaluations in Examples and Comparative Examples were performed using the following methods.

(1) Intrinsic viscosity [η] 25 in a mixed solution of phenol / tetrachloroethane in equal weight
It was measured at ° C.

(2) Haze Measured according to JIS K 6714.

(3) Composition analysis The resin was hydrolyzed with hydrazine and potassium hydroxide, and quantified by gas chromatography and liquid chromatography.

(4) Antistatic property The antistatic property was evaluated at 20 ° C. and 50% R.V. 24 under H
Set the time-adjusted sample on a static Honest meter under the same conditions, and apply a voltage of 10 kV to 3
After applying for a minute, stop the application, measure the change in the electrified voltage from 180 seconds after the electrified immediately after stopping, and determine the time required to reach half the voltage of the electrified voltage immediately after stopping the application as the half-life. did.

The abbreviations in Table 1 indicate the following compounds. TPA: terephthalic acid IPA: isophthalic acid ADA: adipic acid EG: ethylene glycol NPG: neopentyl glycol BPE: bisphenol A ethylene oxide adduct (m + n = 2) TMP: trimethylolpropane PEG: polyethylene glycol PTMG: polyoxytetramethylene glycol DBS: sodium dodecylbenzene sulfonate LS: sodium lauryl sulfonate

Example 1 100 parts by mole of terephthalic acid,
140 mol parts of ethylene glycol was placed in a reaction vessel and polymerized by a direct polymerization method. When a predetermined degree of polymerization was reached, polyethylene glycol (molecular weight 4000) was added in an amount of 5% by weight with respect to the polymer, lithium perfluorooctylsulfonate (C ₈ F ₁₇ SO ₃ Li) to the polymer 0.5
A polyester resin was produced by adding the polymer in an amount of 1% by weight and conducting the polymerization reaction again for a certain period of time. After drying this resin, it is melt extruded at 270 ° C. to prepare a film original fabric, and then this film original fabric is biaxially stretched at 80 ° C. in both longitudinal and transverse directions by 3 times, and a polyester film having a thickness of 30 μm. Got Table 1 shows the analysis results of the resin composition and the evaluation results of the physical properties of the obtained film.

Example 2 100 parts by mole of terephthalic acid,
140 mol parts of ethylene glycol was placed in a reaction vessel and polymerized by a direct polymerization method. When a predetermined degree of polymerization was reached, 3% by weight of polyethylene glycol (molecular weight 10,000) relative to the polymer, potassium perfluorohexyl sulfonate (C ₆ F ₁₃ SO ₃ K) to the polymer at 0.0
5% by weight was added and the polymerization reaction was carried out again for a certain period of time to produce a polyester resin. Then, using this resin, a polyester film having a thickness of 30 μm was obtained in the same manner as in Example 1. Table 1 shows the analysis results of the resin composition and the evaluation results of the physical properties of the obtained film.

Example 3 93 mol parts of terephthalic acid, 7 mol parts of isophthalic acid, and 140 mol parts of ethylene glycol were placed in a reaction vessel and polymerized by a direct polymerization method, and perfluorobutyl was obtained at a stage when a predetermined degree of polymerization was reached. Sodium sulfonate (C ₄ F ₉ SO ₃ Na) was added in an amount of 4% by weight with respect to the polymer, and the polymerization reaction was again carried out for a fixed time to produce a polyester resin. Then, using this resin, a polyester film having a thickness of 30 μm was obtained in the same manner as in Example 1. Table 1 shows the analysis results of the resin composition and the evaluation results of the physical properties of the obtained film.

Example 4 100 parts by mole of terephthalic acid,
140 mol parts of ethylene glycol was placed in a reaction vessel and polymerized by a direct polymerization method. When a predetermined degree of polymerization was reached, polyoxytetramethylene glycol (molecular weight: 1000)
Is added to the polymer in an amount of 3.5% by weight, and sodium perfluorodecylsulfonate (C ₁₀ F ₂₁ SO ₃ Na) is added in an amount of 0.3% by weight to the polymer, and the polymerization reaction is performed again for a certain period of time to produce a polyester resin. did. Then, using this resin, a polyester film having a thickness of 30 μm was obtained in the same manner as in Example 1. Table 1 shows the analysis results of the resin composition and the evaluation results of the physical properties of the obtained film.

[Example 5] 75 mol parts of terephthalic acid, 25 mol parts of isophthalic acid, 130 mol parts of ethylene glycol, 5 mol parts of bisphenol A ethylene oxide adduct, polyoxytetramethyl glycol (molecular weight 100
0) 1.5 mol parts and 0.15 mol parts of trimethylolpropane were placed in a reaction vessel and polymerized by a direct polymerization method. When a predetermined degree of polymerization was reached, polyethylene glycol (molecular weight 6000) was added to the polymer in an amount of 1 0.5% by weight, potassium perfluorodecyl sulfonate (C ₁₀ F ₂₁ SO ₃ K)
Was added to the polymer in an amount of 4% by weight, and the polymerization reaction was again carried out for a fixed time to produce a polyester resin. Then, using this resin, a polyester film having a thickness of 30 μm was obtained in the same manner as in Example 1. Table 1 shows the analysis results of the resin composition and the evaluation results of the physical properties of the obtained film.

Example 6 100 parts by mole of terephthalic acid,
140 mol parts of ethylene glycol was placed in a reaction vessel and polymerized by a direct polymerization method. At a stage when a predetermined degree of polymerization was reached, lithium perfluoropropylsulfonate (C ₃ F ₇ SO 4
₃ Li) was added in an amount of 2% by weight with respect to the polymer, and the polymerization reaction was carried out again for a certain time to produce a polyester resin. Then, using this resin, in the same manner as in Example 1, a thickness of 30 μm
A polyester film of m was obtained. Table 1 shows the analysis results of the resin composition and the evaluation results of the physical properties of the obtained film.

Example 7 82 mol parts of terephthalic acid, 11 mol parts of isophthalic acid, 7 mol parts of adipic acid and 140 mol parts of ethylene glycol were placed in a reaction vessel and polymerized by a direct polymerization method to reach a predetermined degree of polymerization. In the step, polyethylene glycol (molecular weight 6000) was added to the polymer in an amount of 1.5% by weight, potassium perfluorooctylsulfonate (C ₈ F ₁₇ SO ₃ K) was added in an amount of 0.05% by weight to the polymer, and dodecylbenzenesulfonic acid was added. 0.05% by weight of sodium was added to the polymer and the polymerization reaction was carried out again for a certain period of time to produce a polyester resin. Then, using this resin, a polyester film having a thickness of 30 μm was obtained in the same manner as in Example 1. Table 1 shows the analysis results of the resin composition and the evaluation results of the physical properties of the obtained film.

Comparative Example 1 100 parts by mole of terephthalic acid,
140 mol parts of ethylene glycol was placed in a reaction vessel and polymerized by a direct polymerization method to produce a polyester resin.
Then, using this resin, a thickness of 3 is obtained in the same manner as in Example 1.
A 0 μm polyester film was obtained. Table 1 shows the analysis results of the resin composition and the evaluation results of the physical properties of the obtained film.

Comparative Example 2 100 parts by mole of terephthalic acid,
140 mol parts of ethylene glycol was placed in a reaction vessel and polymerized by a direct polymerization method. When a predetermined degree of polymerization was reached, 3% by weight of polyethylene glycol (molecular weight 10,000) was added to the polymer, sodium perfluoroethylsulfonate (C ₂ F ₅ SO ₃ Na) relative to the polymer.
3% by weight was added and the polymerization reaction was again carried out for a certain period of time to produce a polyester resin. Then, using this resin, a polyester film having a thickness of 30 μm was obtained in the same manner as in Example 1. Table 1 shows the analysis results of the resin composition and the evaluation results of the physical properties of the obtained film.

[Comparative Example 3] 100 parts by mole of terephthalic acid,
140 mol parts of ethylene glycol was placed in a reaction vessel and polymerized by a direct polymerization method. At a stage when a predetermined degree of polymerization was reached, 2% by weight of polyethylene glycol (molecular weight 20000) with respect to the polymer, potassium perfluorooctylsulfonate (C ₈ F ₁₇ SO ₃ K) to 0.0
A polyester resin was produced by adding 05% by weight and conducting the polymerization reaction again for a certain period of time. Then, using this resin, a polyester film having a thickness of 30 μm was obtained in the same manner as in Example 1. Table 1 shows the analysis results of the resin composition and the evaluation results of the physical properties of the obtained film.

[Comparative Example 4] 93 mol parts of terephthalic acid, 7 mol parts of isophthalic acid and 140 mol parts of ethylene glycol were placed in a reaction vessel and polymerized by a direct polymerization method, and when a predetermined degree of polymerization was reached, polyethylene glycol ( Molecular weight 2
0000) was added to the polymer in an amount of 5 wt% and lithium perfluorohexyl sulfonate (C ₆ F ₁₃ SO ₃ Li) was added in an amount of 7 wt% to the polymer, and the polymerization reaction was again performed for a certain period of time to produce a polyester resin. Then, using this resin, a polyester film having a thickness of 30 μm was obtained in the same manner as in Example 1. Table 1 shows the analysis results of the resin composition and the evaluation results of the physical properties of the obtained film.

Comparative Example 5 100 parts by mole of terephthalic acid,
140 mol parts of ethylene glycol and 1.5 mol parts of polyoxytetramethylene glycol (molecular weight 1000) were placed in a reaction vessel and polymerized by a direct polymerization method. When a predetermined degree of polymerization was reached, sodium perfluorododecylsulfonate (C ₁₂ F ₂₅ SO ₃ Na) was added to the polymer in an amount of 1% by weight, and the polymerization reaction was performed again for a certain period of time to produce a polyester resin. Then, using this resin, a polyester film having a thickness of 30 μm was obtained in the same manner as in Example 1.
Table 1 shows the analysis results of the resin composition and the evaluation results of the physical properties of the obtained film.

[Comparative Example 6] 100 parts by mole of terephthalic acid,
30 mol parts of neopentyl glycol and 120 mol parts of ethylene glycol were placed in a reaction vessel and polymerized by a direct polymerization method. When a predetermined degree of polymerization was reached, polyethylene glycol (molecular weight 20000) was added to the polymer in an amount of 3% by weight and dodecyl. Sodium benzenesulfonate was added to the polymer in an amount of 0.2% by weight and sodium laurylsulfonate was added in an amount of 0.3% by weight to the polymer, and the polymerization reaction was performed again for a certain period of time to produce a polyester resin. Then
Using this resin, a polyester film having a thickness of 30 μm was obtained in the same manner as in Example 1. Table 1 shows the analysis results of the resin composition and the evaluation results of the physical properties of the obtained film.

[0056]

EFFECT OF THE INVENTION The polyester film of the present invention has excellent antistatic properties without impairing transparency, and has excellent properties such as prevention of whiskers during printing and dust adhesion after coating shrinkage. Since it has the above, it is extremely useful as a shrink wrapping material, other various wrapping materials, and a film material for general industry.

[Table 1]

Front Page Continuation (72) Inventor Seisuke Tanaka 2-1, Ushikawa-dori, Toyohashi-shi, Aichi Sanryo Rayon Co., Ltd. Toyohashi Plant

Claims (2)

[Claims] 1. A film comprising a polyester resin containing a dicarboxylic acid component containing an aromatic dicarboxylic acid or an ester-forming derivative thereof as a main component and a diol component containing ethylene glycol as a main component as constituent components.
A compound represented by the following general formula (I) is blended in the film in an amount of 0.01 to 5% by weight, which is an antistatic polyester film. RfSO ₃ M (I) (In the formula, Rf represents a perfluoroalkyl group having 3 to 10 carbon atoms, and M represents an alkali metal.) 2. A 20 ° C., 50% R.D. Half-life at H is 18
The antistatic polyester film according to claim 1, which is 0 seconds or less.