JPH011533A - composite film - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a biaxially stretched polyester film having excellent antistatic properties and easy adhesion properties.

[Prior art] Conventionally, methods for imparting antistatic properties and easy adhesion properties include:
The following methods were known. That is, as a method for imparting antistatic properties, as shown in JP-A-52-47071 and JP-A-52-47069, various surfactants such as polyethylene glycol and sodium dodecylbenzenesulfonate are kneaded. As shown in Japanese Patent Application Laid-Open No. 49-73443, a method of applying or applying a vinyl resin containing styrene sulfonic acid or its salt as a drawing component is used. is. In addition, methods for imparting easy adhesion include kneading various easily adhesive substances such as polyester copolymers, acrylic resins, and modified polyolefin resins, or methods such as kneading acrylic A thin film of an easy-to-adhesion layer of resin, polyester copolymer, urethane resin, polyvinyl alcohol resin, modified polyolefin resin, ethylene acid-resistant vinyl copolymer, etc. is applied.

[Problems to be Solved by the Invention] However, when various surfactants are used, the antistatic property is highly dependent on humidity and a stable effect cannot be obtained. When the constituent vinyl resin is kneaded to the extent that it exhibits antistatic properties, it has insufficient affinity with polyester, so the interface peels off during stretching, creating voids and deteriorating transparency. On the other hand, in the case of coating, there was also a drawback that the strength of the coating film, especially the resistance to rubbing, was insufficient because the affinity with polyester was insufficient.

- If a highly adhesive substance is mixed in to the extent that the adhesiveness is improved, the problem is that the holding property deteriorates, whereas if it is applied, the adhesion or kneading resistance is insufficient. There were drawbacks.

The present invention improves these problems and improves antistatic properties, adhesive properties,
The purpose is to provide a composite film with excellent coating strength.

[Means for solving the problems] The composite film of the present invention has sulfone rf in the surface layer:
or the concentration of sulfonate is 0.002-2.0%
On at least one surface of the polyester film, a compound having the general formula (where R is hydrogen or a methyl group, M is hydrogen, an alkali metal, an alkaline earth, or ammonium, R+, R2, R
3, R4 is hydrogen, halogen, alkyl group, or alkoxy group respectively) 5% by weight of a polymer whose main constituent is a repeating unit of
It is characterized in that a layer containing 95% by weight or less is coated and then stretched.

The polyester in the present invention includes ethylene terephthalate, ethylene α, β-bis(2-chlorophenoxy)ethane-4,4-dicarboxylate, ethylene α, β-
The main component is at least one structural unit selected from bis(phenoxy)ethane-4,4-dicarboxylate and ethylene 2,6-naphthalate units.

Further, other components other than those mentioned above may be copolymerized within a range that does not impede the present invention, preferably within 10 mol%.

The film of the present invention has the above-mentioned composition as a main component, but various polymers may be blended within the range that does not impede the purpose of the present invention, and antioxidants, heat stabilizers, lubricants, ultraviolet absorbers, Inorganic or organic additives such as nucleating agents may be added to the extent that they are normally added.

In the present invention, the method of adding sulfonic acid or its salt is not particularly limited, but it is in the form of a polymer, preferably in the form of a polymer with an average molecular weight ff of 11,000 or more, more preferably 1
Preferably, it is added in the form of a polymer of 10,000 or more. Polymers containing sulfonic acid or its salts are not particularly limited, but representative examples include polymers copolymerized with acrylic acid, acrylic esters, methacrylic acid, methacrylic esters, or styrene, or polymers consisting only of styrene; Examples include polymers in which 03X is used as a part or all of the sicalajζ acid of various polyesters.

However, when using a polymer introduced in such a form, the improvement effect is more remarkable, which is probably due to insufficient compatibility with the base polymer polyester, so it is preferable.

However, −X is not particularly limited, but includes H+, Na+, K
These are cationic ions such as ", -NH4+, -Li+, -Ca", etc. Among them, from the viewpoint of thermal stability when mixed with polyester and extruded, NHa", Li+, Ca", K+
However, L i + , K + and Ca'' are particularly preferred.

In the present invention, the concentration d applied to the film surface layer is 0.
It is necessary to set it to 0.002 to 2.0%. Preferably 0.0
0.06 to 0.8%, more preferably 0.02 to 0.2%. If it is less than 0.002%, the coating film strength is poor,
On the other hand, if it exceeds 2%, the properties of the base polyester will deteriorate.

There are various methods to achieve the concentration in the film surface layer within the range of the present invention, and the concentration is not limited to 1 hour, but representative methods include a method of kneading necessary additives, a method of combining the kneaded layer with the base material, and a method of combining the kneaded layer with the base material. An example of this method is to apply a layer containing specific additives. However, the method of kneading is simple, does not deteriorate the physical properties of the base polyester film, and has excellent coating toughness, and in particular, the method of kneading using the method described below. is excellent. That is, the melt viscosity of the base film at the melt extrusion temperature is 1/2 that of the base polyester.
Hereinafter, a compound having a sulfonic acid or a sulfonate salt, which is preferably 1/3 or less, more preferably 1/8 or less, is added to the so-called compression ratio (feed section and metal ring), which is a parameter indicating the degree of kneading in the extruder. Mixing with a specified polyester using an extruder with a ratio of polymer filling m (cross-sectional area ratio) of 3.8 or more, and the time from the introduction of the polymer until it is discharged from the nozzle is 10 minutes or more, preferably It is preferable to carry out extrusion molding on a cooling drum for a period of 15 minutes or more and 120 minutes or less, followed by stretching and heat treatment. In a film prepared in this way, the concentration of sulfonic acid or sulfonate in the surface layer is particularly high compared to the center of the film, so it is possible to increase the toughness of the coating without deteriorating the properties of the base material. It is necessary because it is possible.

However, in the present invention, the f2 degree of sulfonic acid or sulfonate refers to C in the outermost layer 100 degrees under the measurement conditions shown below using Shimadzu X-ray photoelectron spectroscopy ESCA750.
for S2. Let S be expressed as the relative intensity ratio of .

1. Measurement conditions 1. Excitation X-ray: MC] Kα1,2 ray (1253,6eV)
Feeding crab 8kV, 30mA Temperature: 20'C Vacuum degree: io-"pa Main constituent component is a repeating unit of the general formula (R, M, R1, R2, R3, R4 are as described above) in the present invention A true polymer is a polymeric sulfonic acid salt or a polymeric sulfonic acid containing different rates of introduction of sulfonic groups.There is no restriction on the rate of introduction of sulfonic groups, but from the viewpoint of the effect of improving conductivity and adhesiveness, The ratio is preferably 40 to 100 mol%.More preferably 75 mol% to 100 mol%, still more preferably 90 mol% to 100 mol%.Of course, the above-mentioned compound with the styrene, methacrylic acid, etc. ester),
Symbiotic compounds with acrylic acid (ester) and fumaric acid (ester) are also included in the present invention, but the compound exhibiting the above-mentioned clothing cost is 40 mol% or more, preferably 60-6 or more, more preferably 90% It is preferable from the viewpoint of electrical conductivity that it accounts for 100% or less.

The weight average molecular weight is not particularly limited, but is 1000 to 50
00,000 is preferable, more preferably 2,000 to 1,000,000,
More preferably, it is 10,000 to 500,000.

The coating layer to be provided on the base material is a mixture of a polymer whose main groove component is a repeating unit called -fukuyo, and other resins.

Although the resin to be mixed is not particularly limited, it is preferable to mix it with a water-soluble or water-dispersible resin from the viewpoint of being able to be applied in the form of a water-based paint and from the viewpoint of dispersibility. Water-soluble or water-dispersible resins include polyester resins, acrylic resins, polyamide resins, urethane resins, vinyl resins, butadiene resins, epoxy resins, silicone resins, or mixtures thereof. , thermosetting ↑".

Use medylol or alkylol resins such as urea-based, melamine-based, acrylamide-based, polyamide-based resins, and epoxy resins as crosslinking agents to improve coating layer consistency (blocking properties), water resistance, solvent resistance, and mechanical strength. The coating layer may contain a reactive compound such as a compound, an aziridine compound, a block polyisocyanate, or a vinyl compound.

The five layers of the coating of the present invention may optionally contain antifoaming agents, properties improvers, thickeners, organic lubricants, inorganic fine particles, antioxidants, ultraviolet absorbers, foaming agents, dyes, Contains pigments etc.
I! You can stop.

To improve the applicability and adhesion of the coating agent to the film,
Although the film may be subjected to chemical treatment or electric discharge treatment before coating and stretching, it is not particularly necessary in the present invention because the affinity with the base film is improved.

Polyurethane as water-soluble or water-dispersible resin,
It is preferable to use polyester or alkyl resin from the viewpoint of adhesiveness and transparency. Specific examples of suitable poly-1-cretanes include those in which the polyurethane has at least one of a carboxylic acid group, a sulfonic acid group, and a sulfuric acid half-ester base, and among these, those in the form of an ammonium salt.

Further, as a specific example of a suitable polyurethane, 0.5 to 20 mol% of 5-sulfosodium isophthalic acid is used.
Copolymerized polyesters can be mentioned. Among them, at least one of terephthalic acid, isophthalic acid, and adipic acid is used as an acid component, and ethylene glycol, hexane glycol, 1,4-
At least one of butanediol, diethylene glycol, neopendel glycol, and tetramethylene glycol
It is particularly preferable to use a polyester having seeds and a viscosity of 3 to 6 cps when diluted by 5% by weight, since not only the adhesive and antistatic properties but also the surface of the composite layer are smooth and the film is excellent in gloss.

Examples of acrylic resins include those containing alkyl acrylate or alkyl methacrylate as a main component, and 30 to 99.9 mol% of this component and a vinyl monomer that is copolymerizable with these and has a functional group. A water-soluble or water-dispersible resin containing 70 to 0.1 mol% of the component is preferred.

Vinyl '41m, which is copolymerizable with alkyl acrylate-1 or alkyl methacrylate and has a functional group, can be used to impart hydrophilicity to the resin and improve the water dispersibility of the resin, or to combine the resin with a polyester film, 11 installed on the undercoat layer! ! It is preferable to have a functional group that improves the adhesion with the coating layer 5. Preferred functional groups include a carboxyl group or a salt thereof, an acid anhydride group, a sulfone 1% or a salt thereof, an amide group, or an alkyl group. Rolled amide groups, amino W (including itff-converted amino groups) or alkyrolled amino groups or salts thereof, hydroxyl groups, epoxy groups, etc. Particularly preferred are carboxyl groups or salts thereof, acid anhydrides. These groups include chemical groups, epoxy groups, etc. Two or more types of these groups may be contained in the resin.

The reason why the content of alkyl acrylate or alkyl methacrylate in the acrylic resin is preferably 30 mol % or more is because coating formability, coating film strength, and blocking resistance are improved. Alkyl acrylate or alkyl methacrylate in acrylic resin is 99.9
The reason why the amount is preferably below mol% is that by introducing a compound having a specific functional group into the acrylic resin as a copolymerization component, it becomes easier to water-solubilize and water-disperse, and the state is stabilized over a long period of time. In addition, it is possible to improve the adhesion between the coating layer and the polyester film layer, improve the strength, water resistance, and chemical resistance of the coating layer by reaction within the coating layer, and further improve the bonding between the film of the present invention and other materials. This is because it can improve adhesion.

Examples of the alkyl group in alkyl acrylate or alkyl metaflerate include methyl group, ethyl group, n-
Propyl group, isopropyl I1. Examples include n-butyl group, isobutyl group, t-butyl group, 2-ethylhexyl group, lauryl group, stearyl group, and cyclohexyl group.

As the vinyl monomer having a functional group copolymerizable with alkyl acrylate or alkyl methacrylate, the following compounds having functional groups such as a reactive functional group, a self-crosslinking functional group, and a hydrophilic group can be used.

Examples of compounds having a carboxyl group or a salt thereof, or an acid anhydride group include acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, metal salts of these carboxylic acids with sodium, ammonium salts, etc. Examples include maleic anhydride.

Examples of compounds containing 1% sulfone or a salt thereof include vinyl sulfonic acid, styrene sulfonic acid, metal salts of these sulfonic acids with sodium, and ammonium salts.

Examples of compounds having an amide group or an alkylolated amide group include acrylamide, methacrylamide, N-methylmethacrylamide, methylolated acrylamide, methylolated methacrylamide, ureido vinyl ether, β-ureido isobutyl vinyl ether,
Examples include ureidoethyl acrylate.

Examples of compounds having amino groups or alkylolated amino groups or salts thereof include dimethylaminoethyl vinyl ether, 2-aminoethyl vinyl ether, 3-aminopropyl vinyl ether, 2-aminobutyl vinyl ether, dimethylaminoethyl methacrylate, dimethyl Examples include aminoethyl vinyl ether, those obtained by methylolizing their amino groups, alkyl halides, and those obtained by chlorinating dimethyl (12) with sultone or the like.

Examples of compounds having a hydroxyl group include β-hydroxyethyl acrylate, β-hydroxyethyl methacrylate,
β-hydroxypropyl acrylate, β-hydroxypropyl methacrylate, β-hydroxy vinyl ether, 5-hydroxypentyl vinyl ether, 6-hydroxyhexyl vinyl ether, polyethylene glycol monoacrylate, polyethylene glycol monomethacrylate, polypropylene glycol monoacrylate, polypropylene glycol monoacrylate Examples include methacrylate.

Examples of compounds having an epoxy group include glycidyl acrylate and glycidyl methacrylate.

In addition to the above compounds, the following compounds may be used in combination. i.e. acrylonitrile, methacrylaterile,
Styrenes, butylene vinyl ether, mono- or dialkyl maleic acid esters, mono- or dialkyl fumaric acid esters, mono- or dialkyl itaconic acid esters, methyl monyl ketone, vinyl chloride, vinylidene chloride, vinyl acetate, vinylpyridine, vinylpyrrolidone, vinyltrimethoxysilane Examples include, but are not limited to, these.

Acrylic resins may contain surfactants, but the low-molecular-weight star surfactants contained in acrylic resins condense during the film-forming process and accumulate at the interface between particles, or the coating layer This may cause problems with the mechanical strength, water resistance, and adhesion of the coating layer to the laminate. In such a case, a polymer obtained by so-called soap-free polymerization that does not contain a surfactant can be used.

However, among these, water-dispersible acrylic in which the copolymer of methyl methacrylate and methyl acrylate at a molar ratio of 35/65 to 65/35 is used as a polymer and 1 to 5% by weight of each of -COOHl-CH20H is introduced is particularly preferred. be.

In the coating layer of the present invention, as explained above, -
Small aggregates whose main constituent is a repeating unit called clothing is 5%.
It is necessary that the content be 95% by weight or less.

If the amount is less than 5% by weight, the adhesion improving effect and antistatic property will be insufficient, which is undesirable. On the other hand, if it is more than 95% by weight, the toughness of the coating film will be poor. Especially when it is 10% by weight to 30% by weight, adhesiveness,
It is preferable because it has a good balance between coating film toughness and antistatic properties.

The thickness of the coating layer after stretching is not particularly limited, but is usually 0.
．． 001 to 5 μm. Preferably 0°01-0.4
μm, more preferably 0.04 to 0.2 μm, from the viewpoint of adhesiveness and antistatic properties.

Further, inorganic particles may be added to the coating layer if necessary, but to give a typical example, the above-mentioned inorganic particles have an average particle diameter of 1 μm or less, more preferably 0.5 μm or less, and particularly preferably is 0.2 μm or less, and specific examples include kaolin, silica, silica sol, calcium carbonate, titanium oxide, barium salts, alumina, molybdenum sulfide, carbon black, and zirconiums, but are not limited to these. do not have.

However, among these, when using a layered silicate exhibiting swelling properties, it is preferable from the viewpoint of easy slipping and coating film toughness. Examples of layered silicates that exhibit swelling properties include montmorillonite, vermiculite, hectorite, duolite, and tetrasilicic mica, but from the viewpoint of transparency, synthesized taeniolite, hectorite, and tetrasilicic mica are preferred. is preferred.

Next, a typical manufacturing method of the present invention will be described, but it is not limited thereto.

First, polyester pellets containing a compound containing a sulfonic acid or sulfonate salt and various other additives as necessary are thoroughly dried, and then put into a known extruder, preferably a melt extruder with a compression ratio of 3.8 or higher. The pellets are supplied, melted and extruded into a sheet through a slit die at a temperature higher than the temperature at which the pellets melt and at a temperature higher than the temperature at which the polymer is heated, and solidified by cooling to form an unstretched sheet. After providing a predetermined coating layer on the unstretched sheet or a film obtained by stretching the unstretched sheet 3 to 8 times at 80 to 105°C,
0'C, and when using an unstretched film, the longitudinal direction is 3~
Simultaneous biaxial stretching is carried out by 6 times, 3 to 6 times in the transverse direction, or 3 to 6 times in the transverse direction when using a -axially stretched film.

Further, if necessary, heat treatment is performed at 150''C to 250C for 0 to 10 seconds while giving 0 to 10% relaxation.

Further, if necessary, the film may be stretched again in the longitudinal direction by 1.1 to 1.7 times.

It goes without saying that coating may also be carried out on a composite of a polyester to which a compound containing sulfonic acid or a sulfonic acid salt has been added and ordinary polyester.

If necessary, a corona discharge treatment may be performed in air in a very fine atmosphere before coating on a film. Anchor treatment may also be performed using a known anchor treatment agent such as urethane resin or epoxy resin, but this is usually not necessary.

The coating method is not particularly limited, and extrusion lamination and melt coating methods may be used; however, gravure coating, which uses a paint dispersed in water or various solvents, is preferred because it is possible to coat a thin film at high speed. It is preferable to reverse coat, spray coat, hard coat, coat coat, or metallize bar two.

[Function] In the present invention, on a polyester film in which the concentration of sulfone M9 or sulfonate in the surface layer is within a predetermined range, a polymer having a repeating unit of the formula % as a main groove component is applied. Since the layer containing the film was stretched after being applied, the affinity with the paint film was improved without deteriorating the properties of the base film, resulting in an easily adhesive and antistatic film with excellent paint film toughness. It was possible.

[Method for evaluating properties and effects] (1) The film with adhesion strength 17 was rubbed by hand 10 times to examine the adhesion state of the five coated layers. If there is no peeling at all, ``◎'', 5
Those with less than % peeling were rated "○", and the others were rated "x".

(2) Transparency S E P -14-2 type turbidity meter (Japan Seimitsu Kogaku ■)
If the upper value of the haze value (%) determined based on J Is-6714-58 is 20% or less compared to the case without the addition of the sulfonic acid salt compound, it is marked as "○", and it is marked as "○". If it is large, it is marked as "×".

(3) Antistatic super insulation resistance meter MODEL-VE-40 (Kawaguchi Electric Industry Co., Ltd.
! 1) 20'C60%RH at 100V pressure applied
The surface resistivity was measured.

(4) Adhesion The following four types of coatings a), b), C) and d) were individually applied to the coating layer surface of the biaxially oriented polyester film, dried or crosslinked, and then applied 10 times by hand. After peeling, a commercially available cellophane adhesive tape was applied with Chiban (manufactured by Taiyo) and peeled off in the 90' direction, and the state of peeling of the coating layer after peeling was evaluated. Those that did not peel off at all were rated "◎", those that hardly peeled off were rated "U○", and the others were rated rXJ. Note that the table below shows the evaluation results when using Shino, which had the worst adhesiveness among the four types of paints.

a) Ultraviolet curable ink (UV ink)... Toyo Ink (FDO (ink) made by Taiyo is applied to a thickness of about 5 μm using a gravure coater, irradiation output is 180 W/cm, and irradiation distance is 10 cm.
was processed for 8 seconds.

b) Polyvinyl alcohol (PVA) having a degree of polymerization of 1500 and a degree of saponification of 90% was dissolved in water and coated to give a coating thickness of 5 μm after drying. 130' after coating 5
Drying was performed at C for 2 minutes.

C) Cellulose acetate butyrate (CAB) with a degree of acetylation of 13% and a degree of butylation of 37% is dissolved in water and a coating film [Si, 150
'C for 2 minutes.

d) Magnetic paint...The thickness of the following composition after drying is approximately 2.
It was applied to a thickness of 5 μm and dried at 150°C for 2 minutes.

・7'-Fe203 powder 68 parts by weight ・Carbon black 7 parts by weight ・Vinyl chloride-vinyl acetate-vinyl alcohol copolymer 26 parts by weight ・Acrylonitrile to butadiene copolymer 5 parts by weight ・Polyisocyanate 1 to 2 parts by weight・Methyl isobutyl ketone
75 parts by weight/Toluene 75 parts by weight [Example] The present invention will be explained using the following Examples and Comparative Examples, but the present invention is not limited to these Examples.

Examples 1 to 6, Comparative Examples 1 to 3 In polyethylene terephthalate with an intrinsic viscosity of 0.61,
Terephthalic acid 82 mol% and isophthalic acid 8 mol% as acid components
A resin prepared by mixing various amounts of a polyester copolymer with a molecular weight of about 30,000 and using ethylene glycol as a diol component (the surface layer of the resin S in
2. /C1S shown in the table was melted at 285°C using a scricoe with a compression ratio of 3.8, and the surface temperature was 50'C.
It was extruded onto a cold J-11 drum. At this time, the time from polymer injection to polymer discharge was 18 minutes. After stretching the thus prepared film 4 times in the longitudinal direction at 85°C, the main component was a 50:50 copolymer of methyl methacrylate-1 and methyl acrylate, and carboxyl groups were used as the functional bases. , as a water-dispersible acrylic resin with a number average molecular weight of 500,000, into which 2.5 mol% of each mediroll was introduced, and the X+ ion of SOq O-X+).
VER8A-TL72 (manufactured by Kanebo NSC) was used as a sulfonated polystyrene with a weight average molecular weight of about 70,000 and the solid content ratio was changed (the ratio is shown in the table).Size 5 The coated layer was stretched 3.5 times in the transverse direction at 110°C while drying, and then stretched at 215°C.
The heat treatment was performed while relaxing by 5%. The thickness of the film obtained at this time was 14 μm, and the thickness of the J5 layer was 0.07 μm.

As shown in the table, it can be seen that only when the composition falls within the range of the present invention, an excellent balance between adhesion, adhesion and transparency can be achieved.

Example 7 Sulfonated polystyrene (in the form of sodium salt) was added as a compound to be mixed with polyethylene terephthalate. Film formation was evaluated in the same manner as in Example 1. It can be seen that it also exhibits excellent transparency and adhesion.

[Effects of the invention] In the present invention, the agricultural degree of sulfonic acid or sulfonate in the surface layer of the base polyester film is set to 0.00.
By binding 2% to 2.0% by weight, the following excellent effects could be obtained.

(1) Adhesion to the base material, especially kneading resistance, was improved.

(2) The resulting film showed excellent transparency.

(3) Shows excellent antistatic properties.

(4) Improved adhesion with inks and various binders.

Claims (1)

[Claims] (1) On at least one surface of the polyester film, the concentration of sulfonic acid or sulfonate in the surface layer is 0.002 to 2.0%, there is a general formula ▲ mathematical formula, chemical formula, table, etc. ▼ (However, R is hydrogen or methyl group, M is hydrogen, alkali metal, alkaline earth or ammonium, R_1, R_2,
R_3 and R_4 are each hydrogen, halogen, alkyl group, or alkoxy group) 5% by weight of a polymer whose main constituent is a repeating unit
A composite film characterized in that a layer containing 95% by weight or more is applied and then stretched.