JP3105343B2 - Easy adhesion polyester film having improved chargeability and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an easily-adhesive polyester film having improved chargeability and a method for producing the same, and more particularly, to an electrostatic failure (discharge ignition accident) which occurs in the production of magnetic tapes, chemical matte films and the like. The present invention relates to a polyester film having no adhesiveness and excellent adhesion to magnetic paints, chemical matte paints and the like, and a method for producing the same.

[0002]

2. Description of the Related Art Thermoplastic polyesters such as polyethylene terephthalate, poly (1,4-cyclohexylene dimethylene terephthalate), polyethylene naphthalate or copolymers thereof, or blends thereof with a small proportion of other resins, etc. A polyester film obtained by melt-extruding, biaxially stretching, and heat setting is excellent in mechanical strength, heat resistance, chemical resistance, and the like, and is used in various industrial fields. However, since the surface is highly oriented and crystallized, there is a problem that the acceptability of paints, adhesives, inks and the like is poor.

Therefore, as a method for improving the adhesiveness, physical treatments such as corona treatment, ultraviolet treatment, plasma treatment, EB treatment or flame treatment, or chemical treatments such as alkali, amine aqueous solution, trichloroacetate phenols and the like are used. Is known. However,
These methods have practical disadvantages such as deterioration of the adhesive force with time and contamination of the working environment due to the evaporation of the chemical.

As another means, there is known a method in which a primer layer is provided by applying an easily-adhesive coating film to a film surface by a process other than a normal polyester film forming process. However, in this method, an organic solvent is usually used as a solvent for the coating agent, and it is difficult to say that the coating atmosphere is sufficiently clean. There are safety and hygiene problems such as deterioration.

[0005] Therefore, if this primer treatment is carried out in a polyester film forming process using an aqueous coating agent, there is no adhesion of dust in a clean environment, and there is no danger of explosion or deterioration of the environment due to the aqueous solvent. However, it is advantageous in terms of film performance, economy and safety.

However, the resulting easily-adhesive polyester film is presumed to be due to the fact that different kinds of chemicals are laminated on the surface of the base film, but has the drawback that static electricity is easily generated and the chargeability is high. doing.

[0007]

SUMMARY OF THE INVENTION It is an object of the present invention to provide various coatings applied to polyester films, such as offset inks, gravure inks, silk screen inks, UV-rays, which are free from static electricity damage such as discharge ignition fire.
Excellent for magnetic paints, especially inks, magnetic paints, gelatin compositions, adhesives, electrophotographic toners, chemical matte paints, diazo paints, hard coat paints, UV paints, heat sealability-imparting compositions, inorganic film-forming substances, etc. It is an object of the present invention to provide an easily-adhesive polyester film having improved adhesion and improved chargeability and a method for producing the same.

[0008]

SUMMARY OF THE INVENTION The object of the present invention is as follows.
According to the present invention, at least one side of the polyester film has at least 70 mol% of the (1) acid component in terephthalate.
From lactic acid or 2,6-naphthalenedicarboxylic acid component
Comprising aqueous polyester resin, (2) a polyether compound and (3) Antistatic agent (however, except the conductive polymer
To the sum of the components (1), (2) and (3)
75% by weight or more of component (1) per 100% by weight of component
(3) 10% by weight or more of the components (2) and (3)
An easily-adhesive polyester film having improved chargeability, characterized by having a primer layer of a composition containing a total amount of 15 to 25% by weight , and at least one of the polyester films before the completion of the oriented crystal. On one side, (1) at least 70 mol% of the acid component is terephthalic
Acid or 2,6-naphthalenedicarboxylic acid component
That aqueous polyester resin, (2) a polyether compound and (3) Antistatic agent (excluding a conductive polymer)
With the total amount 1 of component (1), component (2) and component (3)
75% by weight or more of component (1) per 00% by weight, component
(3) 10% by weight or more of the components (2) and (3)
An aqueous coating liquid of a composition containing a total amount of 15 to 25% by weight is applied, and then dried, stretched, and further subjected to a heat treatment to complete orientation crystallization. This is achieved by a method for producing an adhesive polyester film.

In the present invention, the polyester constituting the polyester film is a linear saturated polyester synthesized from an aromatic dibasic acid or an ester-forming derivative thereof and a diol or an ester-forming derivative thereof. Specific examples of the polyester include polyethylene terephthalate, polyethylene isophthalate, polybutylene terephthalate, poly (1,4-cyclohexylene dimethylene terephthalate), and polyethylene-2,6.
-Naphthalenedicarboxylate and the like, and examples thereof include copolymers thereof and blends thereof with a small proportion of other resins.

[0010] The linear saturated polyester in the present invention comprises:
It may contain an agent for improving the film properties such as a lubricant, an antistatic agent, a coloring agent, a flame retardant, a light-shielding agent, a stabilizer, and an ultraviolet absorber. The lubricant may be either internally precipitated particles or externally added particles, or may be a combination of two or more. As the externally added particles, for example, silica, kaolin, calcium carbonate, calcium phosphate,
Titanium oxide and the like can be mentioned, and as the internally precipitated particles, for example, those precipitated during the production of polyester with a combination of an alkali (earth) metal compound, a phosphorus compound and the like can be mentioned.

The polyester in the present invention is known per se and can be produced by a known method. Inherent viscosity of polyester (O-chlorophenol, 35
C) is preferably from 0.45 to 0.9.

In the present invention, the polyester is melt-extruded by a conventional method and cooled and solidified to obtain an amorphous unstretched film. The unstretched film is first stretched in the longitudinal direction, and then stretched in the transverse direction. These stretchings are performed by running a film. A known means can be used for the stretching means in the longitudinal direction and the transverse direction. For example, in the longitudinal stretching (longitudinal stretching), the unstretched film is heated by a heating roll group,
This is performed using the peripheral speed difference between the low-speed roll and the high-speed roll. At that time, it is preferable to provide an infrared heater between the low-speed roll and the high-speed roll to heat the film to the stretching temperature, or the low-speed roll may heat the film to the stretching temperature.
The stretching in the longitudinal direction is usually performed at a magnification of 2.5 to 4.5 times. The stretching in the transverse direction (transverse stretching) is performed using a tenter-type stretching heat treatment apparatus. This transverse stretching is usually performed in 2.
Perform at a magnification of 5 to 4.5 times. Next, heat treatment is performed at a temperature of 150 to 240 ° C. to complete the oriented crystallization.

The polyester film can be stretched by simultaneous biaxial stretching or multi-stage stretching (vertical-horizontal-vertical, vertical-horizontal-vertical-horizontal, vertical-vertical-horizontal, vertical -side-
Horizontal) can also be used.

In the present invention , at least 70 mol% of the aqueous polyester resin (1) as a primer layer-forming component is used.
Terephthalic acid or 2,6-naphthalenedicarboxylic acid
Is a substantially linear polyester synthesized from a polybasic acid or an ester-forming derivative thereof and a polyol or an ester-forming derivative thereof.

The polybasic acid component of the polyester is
At least 70 mol% of terephthalic acid or 2,6-
Consists of naphthalenedicarboxylic acid, but can be used with this
Examples of the polybasic acid component, isophthalic acid, phthalic acid, 1,
Examples thereof include 4 -cyclohexanedicarboxylic acid, adipic acid, sebacic acid, trimellitic acid, pyromellitic acid, and dimer acid. Two or more of these components can be used. Furthermore, maleic acid,
Unsaturated polybasic acids such as fumaric acid and itaconic acid and P-
Hydroxybenzoic acid, p- (β-hydroxyethoxy)
A small proportion of a hydroxycarboxylic acid such as benzoic acid can be used. The proportion of the unsaturated polybasic acid component or hydroxycarboxylic acid component is at most 10 mol%, preferably 5 mol%.
It is as follows.

The polyol component includes ethylene glycol, 1,4-butanediol, neopentyl glycol, diethylene glycol, dipropylene glycol, 1,6-hexanediol, 1,4-cyclohexanedimethanol, xylylene glycol, dimethylol. Propionic acid, glycerin, trimethylolpropane,
Examples thereof include poly (ethylene oxide) glycol and poly (tetramethylene oxide) glycol. Two or more of these can be used.

The above-mentioned polyesters include, for example, an organic sulfonate, a carboxylate, diethylene glycol,
A copolymer obtained by copolymerizing a hydrophilic group-containing compound such as polyethylene glycol and polytetramethylene glycol is advantageous for producing an aqueous dispersion and is preferred. The introduction of this carboxylate usually uses a trifunctional or higher carboxylic acid,
Since the carboxylic acid undergoes branching in the polymerization step and tends to gel, it is desirable to reduce the copolymerization ratio.
In this regard, the introduction of a hydrophilic group using a sulfonate, diethylene glycol, polyalkylene ether glycol, or the like does not cause a problem in the case of a carboxylate, and is more advantageous.

In order to introduce a sulfonate group into the polyester molecule, for example, 5-Na sulfoisophthalic acid, 5-ammonium sulfoisophthalic acid, 4-Na sulfoisophthalic acid, 4-methylammonium sulfoisophthalic acid, It is possible to use an alkali metal salt or an amine sulfonate of a sulfonic acid such as -Na sulfoterephthalic acid, 5-K sulfoisophthalic acid, 4-K sulfoisophthalic acid, 2-K sulfoisophthalic acid, or Na sulfosuccinic acid. preferable. The polyhydric carboxylic acid or polyhydric alcohol having a sulfonic acid salt group accounts for 0.5 to 20 mol%, preferably 1 to 20 mol%, of the total polyhydric carboxylic acid component or polyhydric alcohol component.
Preferably, it accounts for １８18 mol%.

In order to introduce a carboxylate group into the polyester molecule, for example, trimellitic anhydride, trimellitic acid, pyromellitic anhydride, pyromellitic acid,
Compounds such as trimesic acid, cyclobutanetetracarboxylic acid, and dimethylolpropionic acid can be used.
The carboxylate can be obtained by neutralizing the carboxylic acid with an amino compound, ammonia, an alkali metal or the like.

When the hydrophilic group-containing compound is introduced into the polyester molecule, various known methods can be employed. A case where a group of a carboxylate or an organic sulfonate is introduced will be further described. For example, a method of synthesizing a polyester using a compound having a group of a carboxylate or an organic sulfonate in a molecule as one component of a starting material, Such as a method of synthesizing a polyester using a compound having three or more carboxylate therein as a starting material, and then neutralizing a free carboxyl group in the polyester with ammonia, an amine, an alkali metal compound or the like in a medium. There is a way. To further explain the method, for example, a polymer having a free carboxyl group in the side chain is produced using trimellitic anhydride as one component of the polyester raw material, and after the reaction is completed, ammonia water is added to neutralize the aqueous polyester. Can be built. The polyester is preferably produced by a melt polymerization method.

In the present invention, examples of the polyether compound (2) as a primer layer forming component include polyethylene glycol, polypropylene glycol, polyethylene glycol / polypropylene glycol copolymer (block type, random type), and polyethylene glycol / polypropylene glycol copolymer (block). , Random) lower alkyl ethers and self-polymers of aliphatic epoxy compounds. Among them, polyethylene glycol, polyethylene glycol / polypropylene glycol block copolymer, polyethylene glycol / polypropylene glycol random copolymer ether of glycerin, and polyethylene glycol are preferable.

The molecular weight of such a polyether compound, especially polyethylene glycol, is 500 or more, preferably 1000 to 50,000 in weight average molecular weight.

In the present invention, the antistatic agent (3) (excluding the conductive polymer ) of the primer-forming component is preferably an anionic antistatic agent, and among them, sodium sulfonate is preferred. Especially alkyl diphenyl ether disulfonate (lithium, sodium, potassium, etc.)
Is preferred in terms of the function and effect. Since such an antistatic agent also lowers the surface tension of the aqueous coating liquid, a wetting agent for coating the polyester film is often unnecessary. However, when the surface tension lowering ability of the antistatic agent is insufficient, a surfactant may be used in combination. The amount of the surfactant is preferably 1 to 30% by weight, more preferably 2 to 30% by weight based on the total solids of the primer.

In the present invention, when the total ratio of the aqueous polyester resin (1), the polyether compound (2) and the antistatic agent (3) is 100% by weight, 75% by weight of the aqueous polyester resin (1) As described above, it is preferable that the total amount of the antistatic agent (3) is 10% by weight or more and the total amount of the polyether compound (2) and the antistatic agent (3) is 15 to 25% by weight. Water-based polyester resin (1)
If the amount is less than 75% by weight, the adhesion becomes insufficient, the amount of the antistatic agent (3) is less than 10% by weight, or the total amount of the polyether compound (2) and the antistatic agent (3) is 15% by weight
If it is less than 3, the antistatic property is poor, especially in a low humidity atmosphere.

Further, other additives such as an ultraviolet absorber, a pigment, an organic filler, an inorganic filler, a lubricant, an anti-blocking agent, and a crosslinking agent such as melamine, epoxy and aziridine may be used within a range not to lose the effects of the present invention. Can be mixed.

The solid content of the aqueous coating solution is usually 30% by weight.
Or less, and more preferably 10% by weight or less. The amount of coating is preferably 0.5 to ²⁰ g, more preferably 1 to 10 g, per m ² of the running film.

As a coating method, any known coating method can be applied. For example, a roll coating method, a gravure coating method, a reverse coating method, a roll brushing method, a spray coating method, an air knife coating method, an impregnation method, a curtain coating method, or the like may be applied alone or in combination.
The aqueous coating liquid may contain a small amount of an organic solvent for the purpose of assisting the stability of the coating liquid or the coatability of the coating liquid.

The application of the aqueous coating solution may be carried out during the production process of the polyester film, or may be carried out on the polyester film which has been subjected to the biaxial orientation treatment. Of these, it is preferable to carry out the process during the production process of the polyester film, and further to the longitudinally stretched polyester film. However, when the primer is applied before the longitudinal stretching of the roll, heat resistance that can be cut off by the roll stretching is required.

After the application of the aqueous coating solution, a primer layer is formed by drying. If the orientation and crystallization of the polyester film are not completed, for example, a vertically stretched polyester film coated with the aqueous coating solution is used. Is dried and led to processes such as horizontal stretching and heat setting. The longitudinally stretched polyester film to which the aqueous coating solution has been applied is guided to, for example, a stenter, and is transversely stretched and thermally fixed. During this time, the coating solution dries and forms a continuous film on the film. Drying may be performed before or during the transverse stretching.

The low-charging, easily-adhesive polyester film having a primer layer thus obtained is coated with various coatings such as ink for cellophane, magnetic coating, gelatin composition, toner composition for electrophotography, chemical mat coating, It shows high adhesion to a very wide range of paints such as diazo paints and UV inks, especially strong adhesion to magnetic paints and good blocking resistance without tackiness.

[0031]

The present invention will be further described below with reference to examples.

Incidentally, "parts" in the examples means "parts by weight". Each characteristic of the film was measured by the following method.

1. Adhesiveness An evaluation paint is applied to the primer-coated polyester film using a Meyer bar so that the thickness after drying becomes about 4 μm, and dried at 100 ° C. for 3 minutes. After aging at 60 ° C for 24 hours, Scotch tape No. 600 (3
(M company) 12.7 mm wide and 15 cm long were adhered so as to prevent air bubbles from entering, and the top was smoothed with a manual load roll described in JIS C2701 (1975), and the tape was cut into a tape width. The strength when this is peeled 180 degrees is measured.

[Evaluation coating material] In terms of solid content, urethane resin Nipporan 2304 25 parts (Nippon Polyurethane) PVC / vinyl acetate resin Esrec A (Sekisui Chemical) 50 parts Dispersant Ratio P (RIKEN Vitamin) 1 part Agent CTX-860 (Toda Chemical) 500 parts

Is dissolved in a mixed solvent of methyl ethyl ketone / toluene / cyclohexanone to make a 40% solution and dispersed with a sand glider for 2 hours. Thereafter, 25 parts (in terms of solid content) of coronate L as a crosslinking agent are added, and the mixture is stirred well to obtain a magnetic paint.

2. 5cm after blocking the front and back of the polyester film
× 10 cm square, and a weight of 6 kg / cm ² was applied thereto in an atmosphere of 50 ° C. × 70% RH for 17 hours.
Measure cm peel strength. The peeling speed at this time is 100 mm / min.

3. Charging single-sided primer coated film (10 μm × 500 mm × 3
000m) Roll at 23 ° C x 75% RH and 23 ° C x 4
The film is rewound at a speed of 150 m / min in an atmosphere of 0% R, and the amount of the peeling charge of the roll is measured using a digital test electricity measuring device Model- manufactured by Hugle Electronics Co., Ltd.
Measure using 203.

[0038]

Examples 1 to 6 and Comparative Examples 1 and 2 The intrinsic viscosity is 0.65
Of polyethylene terephthalate (containing lubricant) at 170 ° C
After drying for 3 hours at room temperature,
The film was melt-extruded at 80 ° C. to obtain an unstretched film having a thickness of 150 μm. Then, the film was longitudinally stretched 3.8 times by the infrared heater method, and then the aqueous primer solution (solid content 4 wt%) shown in Table 1 was stretched by the kiss coat method. Wet2g / m ^{2 on} one side
At a rate of Subsequently, the film was stretched 3.9 times in the transverse direction at 105 ° C., and then heat-set at 215 ° C. for 6 seconds. At this time, the film thickness was 10 μm, and the thickness of the final primer layer was 0.02 μm. Table 2 shows the characteristics of this film.

[0039]

Comparative Example 3 A biaxially oriented film was obtained in the same manner as in Example 1 except that the primer solution was not applied. Table 2 shows the characteristics of this film.

[0040]

[Table 1]

However, the symbols in Table 1 are as follows. TA; terephthalic acid IA; isophthalic acid QA; 2,6-naphthalenedicarboxylic acid K ₂ ; 5-sodium sulfoisophthalic acid EG; ethylene glycol BPA-4; ethylene oxide adduct of bisphenol-A (4 mol) PEG 1000; molecular weight 1000 Polyethylene glycol PEG20000; polyethylene glycol PEG50000 having a molecular weight of 2,000; polyethylene glycol having a molecular weight of 5,000

[0042]

[Table 2]

As is clear from Table 2, the polyester film of the present invention has low chargeability, particularly low chargeability at low humidity, and excellent adhesiveness and blocking property.

[0044]

According to the present invention, various coatings, such as offset inks and gravure inks, exhibit a low chargeability even under low humidity and are applied to a polyester film.
Silk screen inks, UV inks, magnetic paints, gelatin compositions, adhesives, electrophotographic toners, chemical matte paints, diazo paints, hard coat paints, UV paints, heat sealability-imparting compositions, inorganic film-forming substances, etc. The present invention can provide a low-charge, easily-adhesive polyester film having a primer layer exhibiting excellent adhesion to a magnetic paint and having no tackiness, and a method for producing the same.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI // B29K 67:00 B29L 9:00 (56) References JP-A-61-164831 (JP, A) JP-A-5-320390 (JP, A) JP-A-5-271523 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08J ^7/ 00-7/18 B32B 27/00-27/42

Claims (2)

(57) [Claims] 1. At least one side of a polyester film has at least 70 mol% of (1) an acid component in terephthalic acid.
Acid or 2,6-naphthalenedicarboxylic acid component
That aqueous polyester resin, (2) a polyether compound and (3) Antistatic agent (excluding a conductive polymer)
A composition comprising: a component (1), a component (2) and a component
75% by weight of the component (1) per 100% by weight of the total amount of (3)
% Or more, component (3) 10% by weight or more, and component (2)
Component (3) is contained in a proportion of 15 to 25% by weight in total.
Charging for improved highly adhesive polyester film, characterized in that is provided with a free primer layer. 2. At least one side of (1) an acid component is present on at least one side of the polyester film before the oriented crystal is completed.
0 mol% is terephthalic acid or 2,6-naphthalenediene
Aqueous polyester resin comprising a carboxylic acid component , (2)
Polyether compound and (3) Antistatic agent (however, guide
Component (1), component (2) and
75% of component (1) per 100% by weight of the total amount of component (3)
% By weight, component (3) 10% by weight or more, and component
The total amount of (2) and component (3) is 15 to 25% by weight.
A method for producing an easily-adhesive polyester film having improved chargeability, which comprises applying an aqueous coating solution of a composition containing the above components, followed by drying, stretching, and heat treatment to complete oriented crystallization.