JPS581727A - Production of easily bondable polyester film - Google Patents

Abstract

PURPOSE:To obtain an easily bondable polyester film having improved adhesiveness, by coating a polyester film before the completion of crystallization and orientation, with an aq. soln. of a specified polyester resin, and then orienting said film. CONSTITUTION:The surface of a polyester film before the completion of crystallization and orientation is coated with an aq. soln., an emulsion or an aq. dispersion of a polyester resin having an organosulfonate salt group in the molecule. Said film is dried, oriented and heat-treated to complete orientation and crystallization. Said polyester film before orientation and crystallization includes unorientated film obtd. by melting a polyester with heating and shaping it into a film, and a monoaxially oriented film obtd. by stretching or tentering said unoriented film. Said sulfonate salt group can be introduced into the molecule of said polyester resin by using Na-5-sulfoisophthalte sulfoisophthalate or methylammonium 4-sulfoisophthalate.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing an easily adhesive polyester film. More specifically, a specific thin layer of primer that improves the adhesion between various coatings and polyester films is applied during the manufacturing process of biaxially stretched polyester films to improve the film image and area: mm. Rather than suppressing adhesion, there are various troubles that can occur during coating processing.
- An easily adhesive polyester film that prevents obstructions, etc. when unrolling a roll.

The object of the present invention is to apply various coatings applied to the base fill 5, such as safe 7 no ink, magnetic paint, gelatin composition, offset ink, electrophotographic toner, chemical matte paint, :) 7zo paint, and heat sealing property. It has excellent adhesion to compositions, inorganic film-forming properties, etc., and prevents troubles due to uneven coating and adhesion caused by static electricity during the coating process. It is an object of the present invention to provide an easily adhesive polyester coated with a specific thin layer of a primer that can exhibit the effect of imparting easy adhesive properties even under manufacturing conditions.

Polyesters polymerized from an aromatic dibasic acid or its ester-forming key conductor and a diol or its ester-forming conductor include, for example, polyethylene terephthalate or its copolymer, polyalkylene naphthalate, and K. It is known to melt-extrude and IIH a blend of this polymer and other resins. This heat-stretched polyester film has better heat resistance, gas barrier properties, electrical properties, and chemical resistance than films made of other resins. However, since the surface is highly crystal oriented, the surface has high cohesiveness and poor receptivity to paints, adhesives, and inks.

Therefore, when providing a synthetic resin layer on the surface of a polynisder film, in order to strengthen the adhesion between the two, the substrate surface is subjected to a discharge treatment, ultraviolet irradiation treatment, plasma treatment, or flame treatment. A method of applying a synthetic resin coating after activating the resin has been applied.

However, although these means for activating the surface of a substrate are expected to improve adhesion to the coating material layer by increasing the secondary bonding force due to wetting, the activity thereof decreases over time. In this way, surface activation means are not necessarily necessary.

As another method for increasing the receptivity of the polyester film substrate surface, etching methods have been proposed in which the surface is swollen or partially dissolved with various agents. This acidifies the surface,
The surface is etched by immersing it in chemicals such as alkali, amine aqueous solution, trichloroacetic acid, or phenols to decompose, dissolve, and relax the crystal orientation near the surface, and at the same time reduce the cohesiveness and improve the adhesion of the binder resin. The effect is the most reliable, and the adhesion between the base material and the synthetic resin coating layer provided thereon is strong. However, some of the chemicals used in this method are harmful and can be dangerous to handle, and volatile substances from the chemicals are emitted into the atmosphere, so thorough measures must be taken to avoid contaminating the working environment. There are various disadvantages in practical terms, such as the need for a large injection volume.

As a method similar to this method, there is a method in which a single layer of primer (undercoat layer) is placed on a substrate in advance, a thin surface layer different from the substrate is formed, and then a desired synthetic resin layer is coated. When forming the undercoat layer, the coating process is generally performed in a process different from the film forming process, so there is a risk that dust such as dirt and debris may be mixed into the process process. For this reason, it is necessary to maintain the fine quality of highly processed film products such as audio magnetic tape, video magnetic tape, computer magnetic tape, X-ray photographic film, printing photographic film, and diazomi lcy film. In certain applications, even if 5 easy-adhesive Q surfaces are formed, if there are surface defects due to dust as a base film, it cannot be used in these applications.

In particular, when finishing a base film into a desired processed product, it would be unreasonable and economically or technically advantageous to provide a primer code treatment step in order to modify the surface into a processable surface. It can not be said.

Therefore, if the process for applying the brimer (undercoat) is carried out in an atmosphere that is as dust-free as possible, that is, during the polyester film forming process, it will be possible to fully support the use of the above-mentioned advanced film processed products.

It is desirable to perform in-line subbing processing in such a film forming process. In the prior art, the method of modifying the surface of a polyester film into an easily adhesive surface by brimer treatment is often achieved by applying a composition dissolved in an organic solvent to the surface layer of the film. I came. When performing such a method on film**,
The use of organic solvents should be kept to a minimum as much as possible, since the fugitive organic solvents contaminate the surrounding environment, cause unfavorable safety and hygiene conditions, and adversely affect the film forming process. Therefore, when performing in-line subbing processing in a film forming process, it is preferable to use a composition that uses water as a solvent.
A number of such water-based primer compositions, which are preferable from economic and safety points of view, have been known for a long time, but when in-line subbing treatment is performed using them, the overcoat composition becomes obscured. Even if it shows a remarkable effect on some substances, it has no effect on others, and there is no substance that has surface receptivity that is sufficiently satisfactory for a wide range of uses.

Furthermore, using a well-known ethyleneimine-based, amine-based, or epoxy-based primer, 18M
When performing in-line subbing processing in a booth, insufficient formation of m* may cause a 7't-tsuking phenomenon, resulting in decreased workability and physical properties of the film such as elongation spots, coloring, and discoloration. There are many defects that significantly deteriorate the appearance.

Polyester film can be used to make the film surface vague, making it easier to manufacture many processed film products without sacrificing the excellent properties of polyester film, such as mechanical strength, heat resistance, transparency, and chemical resistance. It is significant that film suddenly became popular as a general-purpose plastic film, and its functionality is now considered important in high-performance luxury minute hands.

As a result of research into a method that would have a large effect on forming an easily adhesive surface, the inventors of the present invention discovered that a specific positive ester resin aqueous solution was applied to a high melting point, highly crystalline polyester film before crystal orientation was completed. It has been found that the polyester film obtained by subsequent stretching and orientation has excellent adhesive properties.

That is, in the present invention, an aqueous solution, emulsion, or aqueous dispersion of a polyester resin having an organic sulfonate group in the molecule is applied to the surface of a polyester film before oriented crystallization is completed, and if necessary, dried. 1. A method for producing an adhesive polyester film, which comprises stretching the film and then subjecting it to a stretching heat treatment to complete the oriented crystallization.

In the present invention, the polyester forming the film is a flocculent saturated polyester with a high melting point and high crystallinity synthesized from an aromatic dibasic acid or its ester-forming derivative and a diol or its ester-forming derivative. Examples of such polyesters include polyethylene terephthalate, polyethylene isophthalate, polybutylene terephthalate, and polyethylene-2,@-naphthalate, and also includes co-electrometallics or blends of any of these with small proportions of other resins. It will be done. The above kneaded saturated polyester resin is melt extruded and made into a film form by a conventional method,
The polyester film of the present invention is obtained by oriented crystallization and heat treatment crystallization. The crystals of this polyester film are oriented to such an extent that the heat of crystal fusion measured by a scanning calorimeter in a nitrogen stream (at a moderate temperature increase of 10° C./min) is usually 4 −/f or more.

In the present invention, a polyester fill film before the completion of oriented crystallization refers to a stretched film obtained by thermally melting the polymer and made into a film as it is; A uniaxial bidirectional film oriented in one direction; K is oriented in two directions (vertical and horizontal directions) at a low magnification, and i# is finally re-stretched in the vertical or horizontal direction to complete oriented crystallization. This includes biaxially stretched films before stretching.

Even if the film is coated with a primer after it has been heat-set by two-wheel stretching to complete crystal orientation, the adhesion between the primer layer and the base material (film) will not be sufficient, so the primer surface layer and the top coat in contact with this will not be sufficient. Even if the layer has good adhesion, it lacks adhesion to the paste base material and satisfactory results cannot be obtained.

An embodiment of the present invention consists in applying an aqueous solution of a specific positive ester resin to the film surface in state IIIK before the oriented crystallization of the film assembly is completed. Therefore, the coated primer layer can provide great adhesion to the interface between the primer layer and the base material layer through stretching and heat treatment of the base material. Furthermore, it is desirable that the primer layer has excellent adhesion to various coated materials to be processed in the next step.

The aqueous liquid of a specific polyester resin that can be applied in Zero-Start WIJ is '1m in the molecule! It is an aqueous solution, an emulsifier, or an aqueous dispersion of a polyester resin having sulfonate groups. The wood-philicity of polyester resins having sulfonate groups in the molecule is increased. In order to introduce a sulfonate group into the molecule, K may be used, for example, 5-Na sulfoisophthalic acid, 5-ammonium sulfoisophthalic acid, 4Nm sulfoisophthalic acid, 4-methylammonium sulfoisophthalic acid, 2-Na sulfoterephthalic acid, 5- Sulfo-alkali metal bases or sulfonic acid amine salt compounds such as sulfoiphthalic acid, 4-sulfoisophthalic acid, 2-sulfoterephthalic acid, and Na-sulfophuccinic acid can be used. The polyhydric carboxylic acid or polyhydric alcohol having a sulfonate group is 2 to 60 mol-1, preferably 8 to 25 mol-1 of the total polycarboxylic acid component or polyhydric alcohol component.
Occupy Morch. If it is less than 2 molar, the hydrophilicity is poor, and 60
If the molar content is exceeded, the water resistance will be poor and it will be disadvantageous in the production of the polymer. Other components used as polyhydric carboxylic acids include terephthalic acid, isophthalic acid, phthalic acid, phthalic anhydride,
λ藝-naphthalene dicarboxylic acid, L4-cyclohexa/
Examples include dicarboxylic acid, adipic acid, sebacic acid, tomellitic acid, pyramellitic acid, dimer acid, and itaconic acid.

Ethylene glycol, L4 as a polyhydric alcohol component
-Butanediol, diethylene glycol, dibu-pyrene glycol, L6-hexanediol, L4-cyclohexane dimetatool, xylylene glycol, dimethylbutionic acid, glycerin, trimethylbutane, poly(ethylene oxide) glycol, poly(teF) An example of this is ramethylene oxide). In addition to these components, human-oxycarboxylic acids such as p-hydroxybenzoic acid and p-(/-hydroxybenzoic acid) can also be used.

This polyester resin is synthesized by a known method from the above-mentioned polycarboxylic acid or its ester-forming derivative and the above-mentioned polyhydric alcohol or its ester-forming derivative.

This polyester resin is made into an aqueous solution in order to form a single layer of primer. Water is used as a homogeneous or heterogeneous medium, and there are methods for completely dissolving the resin in water, and methods for creating an emulsion, dispersion, or suspension. In any case, all methods using water as a medium for forming a single layer of primer are included. In preparing the aqueous liquid, water may be mixed with a small amount of other medium such as an organic solvent. The method for making an aqueous liquid is (1) dissolving the polyester resin in water; (2) making an emulsion or sim* by using an emulsifier, a dispersant, a suspension stabilizer, etc. together with the polyester resin and water; 3) Polyester resin is dissolved in a medium other than water and added to water to form an emulsion or suspension, and the medium is removed; (4) Polyester resin is melted by heating and dispersed by contact with water or other medium. (5) Preparing fine particles of polyester resin in advance and dispersing the particles in water to stabilize them.

The aqueous liquid may have an arbitrary concentration (preferably from al to IIvt), and may be used by adding a required amount of surfactant such as an anionic lid surfactant or a nonionic surfactant during coating. An effective surfactant is one that promotes wetting of the polyester film by reducing the surface tension of the aqueous liquid to 40-./aI or less, and many known surfactants can be used. Examples include polyoxyethylene alkylphenyl ether, polyoxyethylene fatty acid ester, rubitan fatty acid ester, glycerin fatty acid ester, fatty acid metal soap, furkyl sulfate, alkyl sulfonate, alkyl sulfosuccinate, quaternary ammonium chloride, alkyl Examples include amine hydrochloride.

Regarding the coating, it is sufficient that the surface layer of the polyester film is completely covered with the coating film to a thickness of one degree.

It is essential that the primer layer be applied before the crystal orientation of the polyester film is completed.

At this time, any known coating method can be used to apply the polynisnal aqueous liquid to the surface of the polyester film before orientation.

For example, roll coating method, gravure coating method, -1 Le Grandche method, spray coating, air knife: ff-),
Impregnation methods, curtain coating methods, etc. may be applied independently or in combination.

The coating process targets the surface layer of the base material immediately after the unstretched film obtained by melt-extruding and casting the polymer, or immediately after stretching in either the vertical or horizontal direction.

In order to form a single layer of primer and at least exhibit its effectiveness, it is necessary to dry the coating just before undergoing heat fixation, and then heat the coating film for at least 2 seconds at a temperature of at least 120°C. preferable. In addition, coating one layer of ply 1 @ 4-1, take an unsagi stretched film or a -axis stretched film in advance, apply and dry it outside the film production line, and then apply biaxial stretching or -axial stretching. Although heat setting can be carried out in a row 5, it is preferable to apply it in a film production line from the viewpoint of primer treatment effect and economy.

Coated J & adhesive filter 7-7 ink of the present invention, magnetic paint, gelatin composition, amide oil offset ink, toner composition for electrophotography, chemical matte paint, diazo paint, heat-F sealing property imparted It exhibits an extremely wide range of adhesion performance for compositions, inorganic coating-forming substances, and metal vapor deposition substances.

Hereinafter, a detailed explanation will be given with reference to examples.

Note that the measurement items in the examples were measured by the following methods.

1. Adhesive primer coating treatment The upper polyester film was coated with various top coats under the specified conditions, and Scotch tape was used...
- Adhesive so that there are no air bubbles, and then IJI! g
Using a manual load rail described in , cty・1 (l5tS), this sample was peeled off at 7 characters between the bonded laminated parts 55 using Tensilon UM-■ manufactured by Toyo Bold Cane Co., Ltd. at a head speed of 306-. The peel strength at this time is determined, and this is divided by the tape width to obtain a - value. In addition, in the figure 7 peeling, the laminate is placed with the tape side facing down, and the distance between the take-up chucks is 5 mm.

2. Temperature the surfaces coated with surface slippery primer and those not coated with primer. 20℃
The static friction coefficient is measured at a humidity of 60 degrees RH using a constant Sliverley tester manufactured by Toyo Tester Co., Ltd.

1. Plucking resistance Layer two films (15 pixels x 16~) treated side and untreated side together, and this is K! Ky'd pressure t'go
After 24 hours in an atmosphere of °C Two films were peeled off at a speed of 1 cm/min, and the peeling force at that time was determined.If this value exceeds 1 oof/lo in some countries, troubles occur more frequently during film processing.

degree increases.

Table Haze (cloudiness) Japanese dyeing crafts as an integrating sphere type light transmission chapter measurement device -〇N
Using the DH-2 type, total transmittance (〒t) and diffuse transmittance 8 (
Td) Find, Td/'rt x 1o.

The haze value was determined.

In addition, the various top paints used in line 5 for adhesion evaluation are as follows! I did it.

[Preparation of paint for evaluation]

(1) Lacquer thinner K for magnetic paints 2) F cell p-s BSt
/l [: Isobu/<7-L25-containing flake Tycel #] was melted to prepare a 40 ton solution, 419 parts of acid solution was added, and then polyester resin (Desmofene $1,700) was added. (manufactured by Inil Co., Ltd.) 32s part, lithium dioxide 60 gr, soybean oil fatty acid (Region P; manufactured by Riken Vita I 7m) as a dispersant/wetting agent, cationic activator (cationic yABF 1 bottle oil and fat) Put 1 part each of squalene (manufactured by Mikuni) and squalene (shark liver oil), part aS and 8 parts α into a ball mill.Methyl ethyl ketone (hereinafter abbreviated as MEK) / hexanone / toluene W
Further, 282 parts of a mixed solution consisting of 3/4/3 (weight ratio) was further mixed and sufficiently pulverized to form a mother liquor paint (45 wt%
). To 5 parts of this mother liquor, add 48 il of an addition reaction product of trimethylolpurpane and tolurein diincyanate (Coronet L: manufactured by Nippon Polyurethane Industries) to butylacetate, 2 + ot of the xtzs part, and 1 final K of 4.
! ? A 5w1% magnetic paint for evaluation was obtained.

(2)) Gravure printing ink Commercially available gravure ink for cellophane printing whose main binder is cellulose and p-zine oil/fat: CL8
-709 White (manufactured by Dainippon Ink ■) 2 parts of I liquid, toluene/ethyl vinegar/methyl ethyl) 7w 1/
It was diluted with 1 part of a 1/1 mixed solvent to prepare a paint for evaluation.

(3) Gelatin paint Photographic gelatin 10 parts (Nitta Gelatin), Sabonino 1 part 1. In addition to 539 parts of III water, 2 pieces of gelatin paint for simple evaluation were obtained.

The three types of paints described above were applied to the two-wheel polyester film that had completed the crystal orientation described above (for No. 11, the temperature was 80°C).
After drying for 1 minute, apply KI:I coating so that the coating thickness when drying is 60U 24 hr'j:- 5j on average, and (2) for K, the coating thickness when drying at 80℃XLJ minutes is on average L2μ. Naruyo 5 gravure coating, (
Regarding 2), a 112-layer coating was applied so that the coating thickness after drying for 2 minutes at 110 DEG C. was an average of a6j, and the adhesion of these top coats was measured and the results of the first fitting were obtained.

Table 1 Example 1 (a) Preparation of aqueous polyester liquid Terephthalic acid (80 mol%) 5 parts m-sulfoiphthalic acid (20 mol)-ethylene glycol copolyester (molecular weight gzoo)s.

f and nonionic external image activator polyoxyethylene nonylphenyl ether (HLB t L-nonion N820
5■: Nippon Oil & Fats @ 9F ion-exchanged water 3oooFK
A coating solution was prepared by heating and dissolving the solution and then cooling it.

佽) Production of easily adhesive film Melt extrusion of polyethylene terephthalate with a polymer intrinsic viscosity o of 65 measured in 0-liq p7 enol at 26°C onto a rotary drum topsoil maintained at about 20°C 1511
An unstretched film of MikuPun was obtained, which was then stretched 15 times in the machine direction, and then the coating solution prepared in (a) was applied to one side of the uniaxially stretched film by a kiss coating method. After that, it passes through a preheating zone at 98℃, and then passes through a preheating zone at 105℃.
It was stretched 9 times in the transverse direction. Subsequently, the film was heated at 200° C. for 2 seconds to obtain a biaxially stretched ply 1-coated ester film having an average coating weight of 1001 μm and a thickness of 122 μm. Table 2 shows the results of measuring the adhesiveness, surface smoothness, P7 Young resistance and haze of the treated surface of this film.

IIz Table Example 2 Prephthalic acid (8 mol%) in fal of Example 1
-5Nm-sulfoimphthal (20 mol) -terephthalic acid (77 mol%) instead of ethylene glycol copolyester -5Nm-sulfoimphthal (21 mol) -ethylene glycol copolymer (molecular weight 120G)
Table 3 shows the evaluation results of the primer-treated film obtained in the same manner as in Example 1 except that O) was used.

Example 3 In (a) of Example 1, the amount of copolyester was changed to 6
Table 3 shows the evaluation results of the filter of the present invention, which was obtained in the same manner as in Example 1 except that the film was changed from 09 to 35f.

Example 4 Table 3 shows certain results of the film of the present invention obtained in the same manner as in Example 1 except that the amount of copolymerized polyester in the (a) VC of Example 1 was changed from 60p to 45F.

Example 5 In (i) of Example 1, the amount of copolyester was 6
Table S shows the evaluation results of a film obtained in the same manner as in +1 Example 1 except that 0f was changed to 55f.

Example 6 In Example 1, the amount of copolymerized polyester was 6
Table 3 shows the measurement results of the film obtained in the same manner as in Example 1 except that 02 was changed to tot.

Example 1 Example 1f) (Table 8 shows the measurement results of a film obtained in the same manner as in Example 1 except that the al was changed from copolymerized Posinisdel's edible got to 9 oil.

Example 8 The amount of copolymerized polyester in (al) of Example 1 was 6
Table 3 shows the evaluation results of the film of the present invention obtained in the same manner as in Example 1 except for changing the angle from 0f to 12of.

Example 9 The measurement results of a polyester film obtained in the same manner as in Example 1 except that the amount of copolymerized polyester in (a) VC of Example 1 was changed from 6Of to 14OfK are shown in Table 3.

Example 10 In Example 10-), the amount of nonionic surfactant was 9
Table 3 shows the measurement results of a film obtained in the same manner as in Example 1 except that f was changed to 6 f.

Example 11 The measurement results obtained in the same manner as in Example 1 are shown in Table 3, except that instead of heat treatment at 200 °C for 2 seconds in Example 1, heat treatment was performed at 185 °C for 8 seconds. Indicated.

Table 3

Claims (1)

[Claims] 1) On the surface of the polyester film before orientation crystallization is completed, a water, emulsion, or aqueous dispersion of a polyester resin having an organic sulfonate group in the molecule is applied, dried, and then A method for producing an easily adhesive polyester film, which comprises completing oriented crystallization by heat stretching treatment.