JP3097176B2 - Easy adhesion polyester film - 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. More specifically, the present invention relates to an easily-adhesive polyester film having a coating layer having excellent adhesion, blocking resistance, moisture resistance, and smoothness.
In particular, it is an easily adhesive film suitable for a magnetic recording material and the like.

[0002]

2. Description of the Related Art Polyester biaxially stretched films have excellent properties such as mechanical properties, electrical properties, dimensional stability, transparency and heat resistance. It is widely used as many base films such as photographic materials and graphic arts materials. However, the polyester film surface has high cohesiveness and poor adhesion, so various coatings such as a magnetic paint, a chemical mat paint, a diazo photosensitive paint, a gelatin composition, a heat-sealing composition, When applying ink, etc., in order to strengthen the adhesiveness of the coating layer, physical treatments such as corona discharge treatment, plasma treatment, ultraviolet irradiation treatment, etc. Acetic acid, amine, pheno-
A chemical treatment using a metal or the like, or a treatment method using these in combination is known. Above all, the easy adhesion by the primer treatment of the polyester film surface is widely performed due to the advantages of the treatment process, the safety in operation, and the maintenance of high quality of the film processed product, and in the polyester film production process. A method of performing the primer treatment at a stretch is regarded as promising in terms of process simplification and manufacturing cost, and is being actively implemented. Primer used in the above process
As the treating agent, various aqueous compositions have been proposed, among which a composition containing a polyester resin as a main component, which is excellent in applicability to a polyester substrate and adhesion of a coating layer, abrasion resistance, or an acrylic composition Various studies have been made to form a coating layer made of a resin. (JP-B-47-40873, JP-B-49-10243, JP-B-56-5476, JP-A-52-19786,
JP-A-52-19787, JP-A-54-43017, JP-A-56-8845
And JP-A-61-85436 are known. )

[0003]

However, the above-mentioned prior art has the following problems. That is, since the conventional water-soluble polyester has poor solubility, there are many undissolved components, and there is a problem in filtration property. In addition, pinholes are liable to be generated on the coating surface laminated on the polyester substrate, and the wire bar and the like may be clogged to cause uneven coating. Therefore, when the ratio of the water-soluble dicarboxylic acid component such as 5-sulfoisophthalic acid is increased in order to increase the solubility, the moisture resistance and the blocking resistance are deteriorated, and the adhesion is lowered.

The present invention eliminates these drawbacks, has good hot water solubility, is excellent in adhesion to a polyester substrate, has excellent adhesion to various coating layers provided on a coating layer, and has anti-blocking properties. The present invention provides an easily-adhesive polyester film excellent in properties, solvent resistance, moisture resistance, smoothness and the like.

[0005]

The present invention solves such a problem.
To solve the problem, the following means are adopted. Sand
The easily adhesive polyester film of the present invention contains 5-sodium sulfoisophthalic acid on at least one surface of the polyester film , and comprises 1,1,3-trimethyl
Tyl-3-phenyleneindan-4 ′, 5-dicarboxylic
Acid and / or bisphenol S-ethylene oxide
The glass transition point where the adduct is copolymerized is 30 ° C or higher and 13
0. The in which you characterized in that ℃ by laminating at which adhesive layer comprising a water-soluble copolymerized polyester below.

[0006] The polyester constituting the polyester film in the present invention is a general term for polymers having an ester bond as a main bonding chain, and particularly preferable polyesters are polyethylene terephthalate and polyethylene 2 , 6-naphthalate, polybutylene terephthalate, polyethylene α, β-bis (2-chlorophenoxy) ethane 4,4-dicarboxylate, etc. Among these, the quality and economy are comprehensively evaluated. Considering this, polyethylene terephthalate is most preferred. Therefore, hereinafter, polyethylene terephthalate (hereinafter abbreviated as PET) will be described as a typical example of polyester.

PET is at least 80 mol%, preferably 9 mol%.
At least 5 mol% of ethylene phthalate is used as a repeating unit, but other dicarboxylic acid components and diol components may be used within this limited amount range. Also known additives in this PET, for example, heat stabilizers, oxidation stabilizers, weather stabilizers, ultraviolet absorbers, organic lubricants, pigments, dyes, organic or inorganic fine particles, fillers, antistatic agents, A nucleating agent may be blended. The intrinsic viscosity (measured in orthochlorophenol at 25 ° C.) of the above PET film is 0.4
0 to 1.20 dl / g, preferably 0.50 to 0.80 d
Those in the range of 1 / g are suitable for the content of the present invention. The polyester film of the present invention is preferably biaxially oriented in the state where the easily adhesive layer is laminated, from the viewpoint of mechanical and thermal properties, for example, biaxial orientation when the above PET is used as polyester. The PET film is formed by stretching a non-stretched PET sheet or film in the longitudinal direction and the width direction by about 2.5 to 5 times, respectively. The biaxially oriented pattern is obtained by wide-angle X-ray diffraction. Means to indicate The thickness of the PET film is not particularly limited, but is usually preferably 2 to 500 μm, and may be arbitrarily selected depending on the application.

[0008] Gala of the water-soluble copolymerized polyester of the present invention
Transition point (hereinafter referred to as Tg) is 30 ° C or more and 130 ° C or less
Below, preferably from 50 ° C to 120 ° C, more preferably
Is 70 ° C. or more and 110 ° C. or less. If the Tg is less than 30 ° C., the obtained film will have low heat resistance and insufficient blocking resistance. If the Tg exceeds 130 ° C., the adhesion of the film will be poor. In the present invention, water
As the dicarboxylic acid component of the soluble copolymerized polyester, 5-
Indispensable for copolymerization of sodium sulfoisophthalic acid
The resin is soluble in water by copolymerizing the components.
Become As such a copolymerization ratio, all dicarboxylic acid components
Minutes, preferably 5 to 40 mol%, more preferably 10 to 40 mol%.
-30 mol%, particularly preferably 10-2 mol%.
Is good.

The water-soluble copolymerized polyester of the present invention comprises 1,1,3-tol as a dicarboxylic acid component of the polyester.
Limethyl-3-phenyleneindan-4 ', 5-dical
Boric acid (hereinafter sometimes abbreviated as PIDA), and
And / or bisphenol S-ethyl as a diol component
This is to copolymerize a lenoxide adduct. PI
The copolymerization amount of DA is preferably 5 mol% or more,
0 mol% or less, more preferably 10 mol% or more, 50 mol% or less, particularly preferably 20 mol% or more, 40 mol%
It is desirable that the polyester copolymer contains the following.
When the amount is less than 5 mol%, the effect of improving the blocking is hardly exhibited, and when the amount exceeds 60 mol%, the adhesion becomes poor and the solubility of the polymer becomes extremely poor.

[0010] Other dicarboxylic acid components, if a range that does not impair the effects of the present invention, but are not limited to, the solubility of the water-soluble copolymerized polyester, the adhesion of the resulting easy adhesion film, blocking resistance, etc. Therefore, it is preferable that terephthalic acid (hereinafter, sometimes abbreviated as TPA) is copolymerized as a main monomer. Representative examples of other dicarboxylic acid components include isophthalic acid (hereinafter may be abbreviated as IPA), dimethyladipate (hereinafter may be abbreviated as AA), bis (2-chlorophenoxy) ethane -4,4 'dicarboxylic acid, 2,
Examples thereof include 6-naphthalenedicarboxylic acid, but are not limited thereto. Further, the proportion of the dicarboxylic acid copolymer component is not particularly limited as long as it is within the scope of the present invention.

On the other hand, as a diol component of the water-soluble copolymerized polyester of the present invention, bisphenol S-ethylene oxide adduct (hereinafter, may be abbreviated as BPS-EO) is 5 mol% or more and 60 mol% or less. Mol% or less, preferably 10 mol% or more and 50 mol% or less, more preferably 20 mol% or less.
Desirably, it is a polyester copolymer containing at least 40 mol% and not more than 40 mol%. When the amount is less than 5 mol%, the effect of improving the blocking is hardly exhibited, and when the amount exceeds 60 mol%, the adhesion becomes poor and the solubility of the polymer becomes extremely poor. The remaining diol components include ethylene glycol (hereinafter sometimes abbreviated as EG),
1,4-butanediol, 1,3-propanediol,
Examples thereof include 1,5-pentaneddiol, 1,4-cyclohexanediol, 1,6 hexanediol, and polyalkylene glycol, but are not limited thereto. However, in the present invention, the one in which EG is copolymerized in an amount of 50 mol% or more is preferably used in view of the characteristics of the obtained easily adhesive layer.

In the present invention, as a component of the water-soluble copolymerized polyester, dicarboxylic acid PIDA alone or diol BPS-EO alone may be used.
And BPS-EO may be used for the copolymer component.

In the present invention, the main feature is to apply a coating solution composed of the above-mentioned water-soluble copolymerized polyester, and after drying, heat-treat the coating film stretched in at least one direction at a high temperature. It has been found that the performance of the film is dramatically improved.

The degree of orientation of the coating film according to the present invention is 1.03 to 1.0.
It is preferably 5. When the degree of orientation is larger than 1.5, the coating film has insufficient adhesion and the cleavage is easily caused inside the coating film. On the other hand, when it is smaller than 1.03, the moisture resistance, blocking resistance and solvent resistance of the coating film become insufficient, and swelling or whitening easily occurs, which is not preferable. In particular, when the degree of orientation is from 1.1 to 1.40, the characteristics are well balanced, which is preferable. Also,
The thickness of the coating film is 0.001 μm to 2 μm, preferably 0.1 μm to 2 μm.
01 μm to 1 μm, more preferably 0.06 μm to 0.1 μm.
Desirably, it is 5 μm. This means that the thickness is 0.00
When the thickness is less than 1 μm, the effect of improving the adhesiveness is not obtained, and when the thickness is more than 2 μm, the moisture resistance, the blocking resistance, the solvent resistance and the like are unpreferably deteriorated. The thickness of the coating film can be measured by various methods. It can also be obtained from the step.

The limiting viscosity of the water-soluble copolymerized polyester (2
(Measured in orthochlorophenol at 5 ° C.)
1.20 dl / g, preferably 0.60 to 0.90 dl /
Those in the range of g are suitable for the content of the present invention. Further, it is preferable to add a crosslinking agent such as oxazoline to the water-soluble copolymerized polyester of the present invention from the viewpoint of improving blocking resistance, and the effect of the present invention is not impaired in the water-soluble copolymerized polyester coating liquid. Antistatic agent in the range,
Various additives such as a surfactant may be added without any problem. The method of applying the water-soluble copolymerized polyester of the present invention during the production process of the polyester film and stretching it together with the substrate is most preferred. For example, the melt-extruded polyester film before crystal orientation is 2.5-5 mm long in the longitudinal direction.
The film is stretched about twice, and a surface to be continuously applied is subjected to corona discharge treatment, and a coating liquid is applied to the treated surface. The applied film is dried while passing through a stepwise heated zone and stretched about 2.5 to 5 times in the width direction. Further, it is obtained by a method of being continuously guided to a heating zone at 150 to 250 ° C. to complete the crystal orientation. The coating solution used in this case is preferably an aqueous solution in view of environmental pollution and explosion-proof properties. As a method of coating on the substrate film, a known coating method, for example, a reverse coating method, a gravure coating method, a rod coating method, a die coating method, a wire bar method, or the like can be used. Known additives such as heat stabilizers, oxidation stabilizers, weathering stabilizers, ultraviolet absorbers, organic lubricants, and the like in the coating layer (easily adhesive layer) as long as the effects of the present invention are not impaired.
Pigments, dyes, organic or inorganic fine particles, fillers, antistatic agents, nucleating agents and the like may be added.

Next, a method for producing the easily adhesive polyester film of the present invention will be described, but the present invention is not limited thereto.

The PET is dried according to a conventional method, melt-extruded, and the extruded sheet-like melt is cooled and solidified to produce an unstretched PET film. 80 ~ 12
The film is heated to 0 ° C and stretched 2.0 to 5.0 times in the longitudinal direction to obtain a uniaxially oriented film. One surface of the film is subjected to a corona discharge treatment, and an aqueous coating material of the present invention diluted to a predetermined concentration with water is applied to the treated surface. Next, the coated film is stretched 2.5 to 5.0 times in the width direction while being heated to 90 to 140 ° C., and subsequently 160 to 240 ° C.
And heat-treated for 1 to 10 seconds.
During this heat treatment, a relaxation treatment of 3 to 12% may be performed in the width direction as necessary. By applying a coating agent according to the application on the coating layer side of the thus obtained easily adhesive polyester film, various ink printing such as magnetic recording material, cellophane ink, offset ink, ultraviolet curable ink, etc. It is suitably used as a base film for inorganic coatings such as an adhesive for electrophotographic toner, an adhesive for a chemical mat paint, an adhesive for a diazo paint, and an evaporation.

[0018]

[Method for measuring and evaluating characteristic values] The method for measuring characteristics and the method for evaluating effects in the present invention are as follows.

(1) Hot water solubility The copolymerized polyester is stirred and dissolved in hot water at 80 ° C. for 2 hours and at 90 ° C. for 1 hour, cooled, and filtered with a 5 μm filter. From the presence or absence of undissolved components at that time and the filtration rate, the quality of hot water solubility was determined as follows. In addition, since the subsequent evaluation cannot be performed for those that are not dissolved in hot water, they are indicated by (-). ：: No undissolved component and high filtration rate △: Dissolution or problem in filtration properties ×: No dissolution or a large amount of undissolved component and slow filtration rate

(2) Glass transition point (Tg) Differential scanning calorimeter (DS manufactured by PERKIN ELMER)
A sample (10 mg) was set in C-2), and the temperature was increased at a rate of 10 ° C./min, and the top of the endothermic peak was defined as Tg of the polymer.

(3) Adhesion The following coating material is applied on a film (the coating layer is laminated on the coating layer) to form a coating layer, and a cellophane adhesive tape (Nichiban (Nichiban)) is provided on the coating layer. After passing through a nipple with a linear pressure of 50 kg / cm.
It peels off rapidly in the degree direction. The area of the coating layer adhered to the cellophane adhesive tape at that time was determined according to the following criteria. In the following criteria, [基準] or more was regarded as good adhesiveness. ◎: less than 10% ：: 10% or more and less than 20% △: 20% or more and less than 40% ×: 40% or more

[Diferacoat] ・ Diferacoat VD1654 (manufactured by Dainichi Seika Kogyo Co., Ltd.) 100 parts by weight ・ Sumidur N75 (manufactured by Sumitomo Bayer Co., Ltd.) 1 part by weight It was then coated with a bar coater to a thickness of 6 μm and dried at 100 ° C. for 5 minutes.

(4) Moisture resistance The film provided with the coating layer prepared in the above (3) is heated at 50 ° C.
After being left for one week in a 90% RH atmosphere, the same adhesive property evaluation as in the above (3) was performed.

(5) Blocking resistance A film having an easy-adhesion layer provided on the easy-adhesion layer surface (A) and an easy-adhesion layer surface and a biaxially oriented PET film (B) (overlap area) ： 3cm × 4
cm) with a load of 500 g / 12 cm ² at 50 ° C.
After standing for 24 hours in 5% RH, the shear stress at the overlapped portion was measured using a Tensilon tensile tester at a pulling speed of 20%.
It was measured at cm / min and judged according to the following criteria. ○: 0 kg / cm ² or more and less than 1 kg / cm ² △: 1 kg / cm ² or more and less than 3 kg / cm ² ×: 3 kg / cm ² or more

(6) Solvent resistance Ethyl acetate, toluene,
Methyl ethyl ketone, acetone, isopropyl alcohol
And the degree of cloudiness of the easily adhesive layer was determined by the haze-up ratio. A haze-up rate of less than 3% was rated as (○), less than 5% as (△), and 5% or more as (x).

(7) Adhesion between the easy-adhesion layer and the substrate film A cross cut is made on the easy-adhesion layer (100 / c).
m ² ), a cellophane tape (manufactured by Nichiban Co., Ltd.) was adhered to the cross-cut surface, and pressure-bonded with a nipple with a linear pressure of 50 kg / cm ^2. The adhesion was evaluated to the extent that the adhesive layer was transferred to cellophane tape. When the peeled area was less than 5% (○), 5% or more and less than 10% (△), and 10% or more (x).

(8) Thickness of Coating Layer Using a transmission electron microscope (HU-12) manufactured by Hitachi, Ltd., an ultra-thin section of the laminated film was observed to determine the thickness.

(9) Surface roughness (Ra) According to JIS-B-0601, using a stylus type surface roughness meter BE-3E manufactured by Kosaka Laboratory Co., Ltd., a cutoff of 0.0
The average surface roughness Ra (μm) was measured at 25 mm and a measurement length of 4 mm.

(10) Degree of orientation of coating film This is carried out by the infrared polarization ATR method. As the apparatus, an apparatus in which an auxiliary device for polarization ATR measurement (manufactured by Bio-Rad Digilab) is attached to a Bruker FT-IR (IFS-113V) is used. This ATR device has a square Inte having a thickness of 3 mm and a side of 25 mm having a symmetrical edge.
Attach rnal Preference Element and measure absorption in two directions parallel and perpendicular to the stretching direction. The incident direction of the light is set to the flowing direction of the film, and the speckles on the coat surface and the non-coat surface are measured using polarized light perpendicular to the incident surface, and are respectively designated as SMC and SMP. In addition, the incident direction of the light is taken in the width direction of the film, and the speckles on the coat surface and the non-coat surface are measured using polarized light perpendicular to the incident surface,
These are STC and STP, respectively. However, when there is no non-coated surface, the coated surface is wiped with various solvents, water and the like, and then the substrate surface is measured. The difference spectrum between the coated surface and the non-coated surface is determined by the following procedure. As an internal reference band for calculating the difference speckle, an absorption band of a base film observed in a wave number region close to the absorber of the coat layer required for analysis is selected. Determine the coefficient so that the absorbance of the internal reference absorption band becomes 0,
A difference spectrum obtained by subtracting the spectrum of the non-coat surface from the spectrum of the coat surface is obtained for each polarization component, and Sv (SMC−
SMP) and Sp (STC-STP). On the difference spectrum obtained in this manner, points at two predetermined wave numbers are connected as a base line, and the peak of the absorption band is determined from the base line.
The height up to the peak is defined as the absorbance Av (relative to Sv) and Ap (relative to Sp) of the coat layer absorption band. The degree of orientation P is calculated from the absorbances Av and Ap of the coat layer thus obtained. P = | Av-Ap | / (Av + Ap) +1

[0030]

According to the present invention, the coating film having a specific composition as an easy-adhesion layer is applied to at least one surface of the polyester film, dried and then formed into an easily-adhesive polyester film having a stretched coating film. It has the effect that it has.

(1) The adhesiveness to various coating layers is excellent, and the decrease in adhesiveness is extremely small even under high temperature and high humidity.

(2) It also has excellent blocking resistance, good storage stability under high temperature and high humidity, and the solubility is further improved by copolymerizing the component of the present invention. Since the amount is extremely small, it can be suitably used for various applications, particularly for easily adhesive films such as magnetic materials requiring surface smoothness.

[0033]

Next, the present invention will be described with reference to examples, but is not necessarily limited thereto.

Example 1 0.4% of colloidal silica having an average particle size of 0.12 μm and 0.03% of calcium carbonate having an average particle size of 0.8 μm
PET pellets contained (intrinsic viscosity 0.62 dl / g)
After sufficiently dried in a vacuum, supplied to an extruder, melt-extruded at 280 ° C., filtered with a 10 μm-cut metal sintered filter, extruded through a T-type die into a sheet form, and dried.
It was wound around a cooling drum at ℃ and cooled and solidified. In order to improve the adhesion between the sheet and the surface of the cooling drum during this time, a wire electrode was arranged on the sheet side and a DC voltage of 6000 V was applied. The unstretched PET film thus obtained was heated to 95 ° C. and stretched 3.5 times in the longitudinal direction to obtain a uniaxially stretched film. One surface of this film was subjected to corona discharge treatment in an air atmosphere, and the following water-based paint for forming an easily adhesive layer was applied to the treated surface by a gravure coat method. The coating thickness is 0.15 for the easily adhesive layer after biaxial stretching.
μm.

[Water-based paint for easy adhesion layer formation] As a dicarboxylic acid component of the water-soluble copolymerized polyester, 55 mol% of TPA, 15 mol% of SI, 30 mol% of PIDA,
The ester exchange was carried out by heating under stirring in an autoclave using 0.09% of calcium acetate with respect to the acid component as a catalyst at a composition ratio of 100 mol% of EG as the toluene component, and then preventing coloration. 0.04% of trimethyl phosphate was added as an agent and polycondensed to obtain a water-soluble copolymerized polyester of the present invention. The obtained water-soluble copolymerized polyester had an intrinsic viscosity of 0.73 dl / g. When this polymer was used as a 6% by weight aqueous paint, the transparency was excellent and the insoluble content was extremely small. The uniaxially stretched film coated with the water-based paint is guided to a preheating zone heated to 95 ° C., and after drying the water, it is continuously gripped by clips with a heating zone at 100 ° C. and the width is 3 mm. .5 stretching, followed by 225
5% relaxation treatment in the width direction with a heating zone of 10 ° C.
Heat treatment was performed for 2 seconds to obtain a 75 μm-thick easily-adhesive polyester film having an easily-adhesive layer thickness of 0.15 μm.
Tables 1 and 2 show the evaluation results of this easily adhesive polyester film. The adhesion of the various coating layers provided on the easy adhesion layer side of this film was extremely good, and there was no decrease in adhesion even under high temperature and high humidity, and the blocking resistance was also good.

Example 2 P of the polyester copolymer dicarboxylic acid component of Example 1
Instead of IDA, BPS-EO was used as a diol component, and 87.5 mol% of TPA was used as a dicarboxylic acid component.
The thickness of the easily adhesive layer was 0.12 μm in the same manner as in Example 1 except that the polymerization was carried out at a copolymer composition ratio of 12.5 mol%, EG as a diol component, and 70 mol% of BPS-EO.
Was obtained, and an easily adhesive polyester film having a thickness of 75 μm was obtained. The results showed good characteristics as shown in Tables 1 and 2.

Examples 3 and 4 The results are shown in Tables 1 and 2, respectively, but those within the scope of the present invention all showed good characteristics.

Comparative Examples 1 to 3 The results are shown in Tables 1 and 2, respectively, but those out of the scope of the present invention had extremely poor adhesion to the coating layer and poor blocking resistance. In Comparative Example 3, the easy-adhesion layer was not applied at all on the polyester film substrate, and as a matter of course, the adhesion to the coating layer was extremely poor.

[0039]

[Table 1]

[0040]

[Table 2]

Continuation of front page (56) References JP-A-61-164831 (JP, A) JP-A-61-254637 (JP, A) JP-A-61-295037 (JP, A) JP-A-58-1727 (JP) , A) JP-A-60-11358 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B32B 1/00-35/00 C08J 7/04

Claims (3)

(57) [Claims] Claims: 1. A polyester film containing 5-sodium sulfoisophthalic acid on at least one surface thereof .
1,1,1,3-trimethyl-3-phenyleneindan
-4 ', 5-dicarboxylic acid and / or bisphenol
Glass copolymerized with S-ethylene oxide adduct
An easily-adhesive polyester film, wherein an easily-adhesive layer made of a water-soluble copolymerized polyester having a transition point of 30 ° C. or more and 130 ° C. or less is laminated. 2. The 1,1,3-trimethyl-3-phenyl
Renindan-4 ', 5-dicarboxylic acid and / or
Copolymerization of bisphenol S-ethylene oxide adduct
The ratio is 5 mol% or more and 60 mol% or less.
Highly adhesive polyester film of the mounting. 3. After coating and drying a coating solution consisting of the water-soluble copolymerized polyester onto a polyester film, it is stretched in at least one direction, the orientation degree of the coating film 1.03～
3. The easily adhesive polyester film according to claim 1, wherein the polyester film has a thickness of 1.5 to 0.001 to 2.0 [mu] m.