JPH0260941A - Polyester film and its production - Google Patents

Abstract

PURPOSE:To obtain a surface-coated polyester film of excellent adhesiveness and water resistance in an industrially advantageous manner by coating at least one surface of a polyester film with a (co)polymer of an addition- polymerizable oxazoline and stretching the film. CONSTITUTION:At least one surface of a polyester film is coated with a coating agent containing a polymer obtained by polymerizing an addition-polymerizable oxazoline, (a) of the formula with, optionally, at least another monomer (b). This film is stretched to obtain the purpose polyester film. In the formula, R1, R2, R3 and R4 are each H, a halogen, an alkyl, an aralkyl, a phenyl or a substituted phenyl; and R5 is an acyclic organic group having an addition- polymerizable unsaturated bond. As the addition-polymerizable oxazoline (a) used, 2-isopropenyl-2-oxaxoline is particularly desirable because of its industrial availability.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a polyester film having a coating layer and thus having improved surface properties, and a method for producing the polyester film.

[Prior art and problems to be solved by the invention] Polyester films are widely used in the fields of magnetic materials, packaging materials, electrical/electronic materials, and printing materials. Surface coating layers such as coating layers, printing ink layers, or metal vapor deposition layers are provided for the purpose of imparting various functions.

It is important that the adhesion between the surface coating layer and the polyester film is ensured under the usage conditions of each application, and in order to improve the adhesion, polyurethane resin, polyester resin, acrylic resin, etc. are usually used. An anchor coat layer and a primer layer coated with a solution or dispersion of However, adhesion, water resistance,
At present, there is still no surface-coated polyester film that is satisfactory in all aspects of weather resistance.

An object of the present invention is to provide a polyester film provided with a coating layer and an industrially advantageous manufacturing method thereof.

[Means and Effects for Solving the Problems] It has been discovered that a polyester film having a coating layer having the above-mentioned coating layer can achieve the above object, and the present invention has been achieved. Furthermore, by applying a coating agent containing the polymer to a polyester film and then performing a stretching operation, the desired polyester film can be produced industrially easily and more effectively than conventionally known coating agents. They discovered this and arrived at the present invention.

That is, the present invention provides, on at least one side of a polyester film, a compound having the general formula (I) (wherein R+, R2-Rs, and R4 are each independently hydrogen, halogen, alkyl, aralkyl, and phenylmata is a substituted phenyl group). (C, R, is an acyclic organic group having an addition-polymerizable unsaturated bond.) Addition-polymerizable oxazoline (a) represented by The present invention relates to a polyester film characterized by having a coating layer formed from a coating agent containing the obtained polymer.

The present invention also provides a polyester film having at least one side having the general formula (I) (wherein R1-Rt, Ra, and R4 are each independently hydrogen, halogen, alkyl, aralkyl, and phenylmata is a substituted phenyl group, is an acyclic organic group having an addition-polymerizable unsaturated bond. The present invention relates to a method for producing a polyester film, which comprises applying a coating agent and then stretching the film.

Addition-polymerizable oxazoline (a
) is represented by the general formula (I), and specific examples include 2-vinyl-2-oxazoline, 2-vinyl-4-methyl-2-oxazoline, 2-vinyl-5-
Methyl-2-oxazoline, 2-impropenyl-2-
Oxazoline, 2-infurobenyl-4-methyl-2-
ni++I+)n, 2-isopropenyl-5-ethyl-2
-oxazoline, etc., and one or a mixture of two or more of these can be used. Among them, 2-impropenyl-2-oxazoline is suitable because it is industrially easily available.

Other monomers fb) used in the present invention are not limited as long as they are copolymerizable with the addition-polymerizable oxazoline (a), such as methyl (meth)acrylate, butyl (meth)acrylate, (meth)acrylic acid-
(meth)acrylic acid esters such as 2-ethylhexyl; unsaturated carboxylic acids such as (meth)acrylic acid, itaconic acid, and maleic acid; unsaturated nitriles such as (meth)acryloni; (meth)acrylamide; Unsaturated amides such as N-methylol (meth)acrylamide;
Vinyl esters such as vinyl acetate and vinyl propionate; Vinyl ethers such as methyl vinyl ether and ethyl vinyl ether; α-olefins such as ethylene and propylene; Saturated motsumers; styrene, α
Examples include α,β-unsaturated aromatic resins such as -methylstyrene, and one or a mixture of two or more of these can be used.

To obtain a polymer using addition-polymerizable oxazoline (al and, if necessary, at least one other monomer (b)), polymerization may be performed by a conventionally known polymerization method.

For example, in the emulsion polymerization method, various methods can be employed, such as a method in which a polymerization catalyst, water, a surfactant, and a monomer are mixed all at once and polymerized, a monomer dropping method, a multistage polymerization method, and a pre-emulsion method. Conventionally known polymerization catalysts can be used, such as hydrogen peroxide, potassium persulfate, 2,
Common radical polymerization initiators such as 2'-azobis(2-amidinopropane) dihydrochloride can be used. Also,
Examples of the surfactant include conventionally known anionic, nonionic, cationic, amphoteric surfactants and reactive surfactants. The polymerization temperature is usually 0 to 1.
00°C1 Preferably 50 to 80°C, polymerization time is usually 1
-10 hours.

In addition, examples of solvents that can be used when employing the solution polymerization method include toluene, hexane, methyl ethyl ketone, ethyl cellosolve, ethyl acetate, and isopropyl alcohol. can be used. Further, examples of the polymerization initiator include common radical polymerization initiators such as azobisin butyronitrile and benzoyl peroxide. The reaction temperature ranges from room temperature to 200'C1, preferably from 40 to
The range is 120°C.

When obtaining a polymer using addition-polymerizable oxazoline (a) and other monomers (b) as necessary, the amount of addition-polymerizable oxazoline (a) used is 0.5 of the total monomers.
The law can be set as appropriate within the range above the weight limit. If the amount of addition-polymerizable oxazoline fa) used is less than 0.5 wt-fi%, it will be difficult to form a coating layer with good adhesion from the resulting polymer, resulting in poor water resistance and adhesive properties. It becomes difficult to obtain a polyester film with excellent properties. In addition, when considering the compatibility with other resins and economic efficiency when mixing other coating resins with the obtained polymer and using it as a coating agent, addition polymerizable oxazoline (a
) is preferably used in an amount of 80 itfL% or less based on all monomers, and the remainder is preferably selected from other monomers and used in the polymerization. The polymers thus obtained are obtained, for example, in the form of an aqueous dispersion in emulsion polymerization, and in the form of an organic solvent solution in solution polymerization, but these polymers can be used as they are as a coating agent.

It can also be used in combination with conventionally known polyurethane resins, polyester resins, acrylic resins, etc. as coating agents. In addition, when using other coating resins together, the ratio of the polymer to the known resin is preferably 1/100 or more, more preferably 10/100 or more. If the ratio of the polymer derived from addition-polymerizable oxazoline fa) is less than 1/100, a coating agent with excellent adhesion to polyester films may not be obtained depending on the type of known resin used in combination. Furthermore, if necessary, other known substances capable of controlling the transmission of light absorption, lubricants, antistatic agents, water repellents, crosslinking agents, pH adjusters, wetting agents, viscosity modifiers, etc. are added to the coating agent. It can also be diluted with water or a solvent as appropriate.

The polyester resin serving as the base material of the polyester film of the present invention includes dihydric alcohols and aromatic dibasic acids or esters thereof, such as polyethylene terephthalate, polybutylene terephthalate, polyethylene-2,6-naphthalene dicarboxylate, etc. It is possible to use thermoplastic polyester resins obtained from.

There are no particular limitations on the method for producing the polyester film having the coating layer of the present invention, and the film produced by a conventional molding method such as melt extrusion or solution casting may be coated with a roll coater, gravure coater, spray, or air. It is necessary to improve the quality and have excellent water resistance and adhesion by applying a coating agent to a predetermined film thickness using a known coating device such as a knife coater or curtain coater and drying it. In order to form a minimally thin film, for example, a coating agent is applied to a polyester film that has been melt-extruded and has not yet been stretched, and then the stretching is completed to a predetermined magnification (
Advantageously, it is produced by an in-line coating method). Here, the polyester film that has not been completely stretched includes an unstretched film, a uniaxially stretched film that is stretched only in one direction, and a low-magnification stretched film that is stretched at a lower magnification than the predetermined magnification.

A particularly preferred manufacturing method in terms of economy and quality of the coating layer is to stretch the melt-extruded polyester resin in the vertical direction to a predetermined magnification, apply the coating agent of the present invention, and then stretch it in the horizontal direction to a predetermined magnification. This is a method of heat fixing.

In the present invention, typical forms of the coating agent include the above-mentioned aqueous dispersion and organic solvent solution.
When producing the film of the present invention by an in-line coating method, an aqueous dispersion is preferred from the viewpoint of ease of handling.

〔Effect of the invention〕

The polyester film of the present invention has a coating layer formed by a coating agent containing a polymer obtained by polymerizing addition-polymerizable oxazoline (al and optionally at least one other monomer fb). Because of this, it has excellent adhesion for various coating agents, inks, deposited films, magnetic recording materials, packaging materials, electrical and electronic related materials,
It can be widely and effectively used as a plate-making/printing material and a photographic film material.

〔Example〕

The present invention will be described in detail below with reference to Examples, but the scope of the present invention is not limited only to these Examples.

In addition, in the examples, unless otherwise noted, the terms "wt%" and "parts" mean parts by weight, respectively.

Reference Example 1 In a flask equipped with a stirrer, reflux condenser, nitrogen inlet tube, thermometer and dropping funnel, adjust the pH to 9 to 9.5 with deionized water and a suitable amount of aqueous ammonia (28%), and slowly add nitrogen to the flask. It was heated to 70'C with flowing gas. 64 parts of a 5% aqueous solution of potassium persulfate was injected therein, followed by monomers of 139.5 parts of butyl acrylate, 436.5 parts of styrene, and 64 parts of 2-impropenyl-2-oxazoline, which had been prepared in advance. The mixture was added dropwise over a period of 3 hours.

During the reaction, nitrogen gas was blown into the reactor to maintain the internal temperature at 70±1°C. After the dripping was completed, the temperature was kept at the same temperature for 2 hours, and then the internal temperature was raised to 8.
The temperature was raised to 0°C and stirring was continued for 1 hour to complete the reaction. Thereafter, it was cooled to obtain an aqueous resin dispersion [1] with a nonvolatile content of 39.8%.

Reference Examples 2 to 3 In Reference Example 1, the same operation as in Reference Example 1 was repeated except that the composition of the polymerizable monomer mixture was changed to the same value as shown in Table 1, and an aqueous resin dispersion [2 ] and [3] were obtained.

Reference Example 4 In a flask similar to Reference Example 1, 200 parts of ethyl acetate, 16.9 parts of styrene, 13.1 parts of butyl acrylate, and 2
- 30 parts of isopropenyl-2-oxazoline was charged,
It was heated to 80° C. while slowly flowing nitrogen gas. 36 parts of azobisisobutyronitrile 10% ethyl acetate solution was injected there, followed by styrene 6 parts prepared in advance.
A monomer temperature mixture of 7.7 parts of butyl acrylate, 52.3 parts of butyl acrylate, and 120 parts of 2-impropenyl-2-oxazoline was added dropwise over 2 hours. During the reaction, nitrogen gas was blown into the reactor to maintain the internal temperature at 80°C±1°C. After dropping, add 10% of azobisisobutyronitrile while keeping the same temperature.
% ethyl acetate solution was added dropwise over 4 hours. Thereafter, stirring was continued for another 1 hour to complete the reaction, and the mixture was cooled to obtain a resin solution [1] with a nonvolatile content of 53.7%.

Comparative Reference Example 1 Comparative aqueous resin dispersion [1 ] was obtained.

Example 1 5% of Kurarayhohar 117 (manufactured by Kuraray ■, polyvinyl alcohol) was added to the aqueous resin dispersion [1] obtained in Reference Example 1.
After adding 20 parts of the aqueous solution to 100 parts of the nonvolatile content in the aqueous resin dispersion [1], an appropriate amount of deionized water was added to adjust the nonvolatile content to 3% to obtain a coating agent [1].

Coating agent [1] was applied in a biaxially stretched film having a thickness of 10 μm and heated at 110° C. for 1 minute to obtain a PET film having a coating layer.

The PET film with the resulting coating layer and the untreated PET film were coated with cellulose butyrate acetate lacquer (
Non-volatile content 4(I) was coated with a bar coater to a dry film thickness of 5μ.
The test film was coated on the film and dried at 110° C. for 1 minute to obtain a test film.

The obtained test film was tested for adhesion and hot water resistance. The results are shown in Table 2.

Adhesion: After adhering a cellophane tape to the coating surface, it was peeled off at once in the 90' direction, and evaluated from 10 points (no peeling) to 1 point (full peeling) depending on the degree of peeling of 1 meter of coating.

Hot water resistance: 90-9 for coated PET film
After being immersed in hot water at 5° C. for 30 minutes, the water on the surface was wiped off and an adhesion test was conducted in the same manner as above.

Example 2 A coating agent [2] was obtained by using the aqueous resin dispersion [2] obtained in Reference Example 2 instead of the aqueous resin dispersion [1] used in Example 1. Using this coating agent [2],
A test film was obtained by repeating the same operation as in Example 1.

Using the obtained test film, the adhesion and hot water resistance tests were conducted in the same manner as in Example 1.

The results are shown in the second coat.

Example 3 A coating agent [3] was obtained by using the aqueous resin dispersion [3] obtained in Reference Example 3 instead of the aqueous resin dispersion [1] used in Example 1. Using this coating agent [3],
A test film was obtained by repeating the same operation as in Example 1.

Using the obtained test film, the adhesion and hot water resistance tests were conducted in the same manner as in Example 1.

The results are shown in Table 2.

Comparative Example 1 In place of the aqueous resin dispersion [1] used in Example 1, the aqueous resin dispersion [1] obtained in Comparative Reference Example 1 was used to obtain a comparative coating agent (I). Using this comparative coating agent [1], the same operation as in Example 1 was repeated to obtain a test film.

Using the obtained test film, the adhesion and hot water resistance tests were conducted in the same manner as in Example 1.

The results are shown in Table 2.

Example 4 Pyronal (water-dispersible polyester manufactured by Toyobo,
87.9 parts of the aqueous resin dispersion (I) obtained in Reference Example 1 was added to 22.1 parts (nonvolatile content: 35%).

Then, the non-volatile content in the resulting aqueous dispersion was reduced to 3% by 100 parts.
Coating agent [4] was obtained. A test film was obtained by repeating the same procedure as in Example 1, except that coating agent [4] was used instead of coating agent [1] in Example 1.

Using the obtained test film, tests for adhesion and hot water resistance were conducted in the same manner as in Example 1.

The results are shown in Table 2.

Example 5 In place of the water-dispersible polyester used in Example 4, Merck 585 (manufactured by Toyo Polymer, water-dispersible polyurethane,
A coating agent [5] was obtained using 22.1 parts (non-volatile content: 35%). Using this coating agent [5], the same operations as in Example 1 were repeated to obtain a test film.

Using the obtained test film, the adhesion and hot water resistance tests were conducted in the same manner as in Example 1.

The results are shown in Table 2.

Comparative Example 2 A comparative coating agent [2] was obtained by repeating the same operations as in Example 4 except that the aqueous resin dispersion [1] was not added to the water-dispersible polyester. Using this comparative coating agent [2], a test film was prepared in the same manner as in Example 1, and its adhesion and hydrothermal properties were tested. The results are shown in Table 2.

Comparative Example 3 A comparative coating agent [3] was obtained by repeating the same procedure as in Example 5, except that the aqueous resin dispersion [1] was not added to the water-dispersible polyurethane. Using this comparative coating agent [3], a test film was prepared in the same manner as in Example 1, and its adhesion and hot water resistance were tested. The results are shown in Table 2.

Example 6 Ethyl acetate was added to the resin solution (I) obtained in Reference Example 4 to adjust the nonvolatile content to 3% to obtain a coating agent [6]. Using this coating agent [6], the same operations as in Example 1 were repeated to obtain a test film. Adhesion and hot water resistance tests were conducted in the same manner as in Example 1 using the obtained test film. The results are shown in Table 2.

Example 7 Using the coating agent [1] obtained in Example 1, a PET film having a coating layer was manufactured by the in-line coating method described below.

In-line coating method: Polyethylene terephthalate is melt-extruded, cast onto a cooling rotating drum, then stretched 3.5 times in the extrusion direction (vertical direction), and then coated with a coating agent using a roll coater.
Stretched 3.5 times laterally (horizontal direction) at 5°C, 200
Heat setting was performed at 0C to obtain a PET film having a film thickness of approximately 12 μm and 5 coating layers each having a thickness of approximately 0.05 μm.

A PE↑ film having a coating layer was produced by repeating the same operation as in Example 7.

Using the obtained PET film, a test film was prepared in the same manner as in Example 7, and tests for adhesion and hot water resistance were conducted. The results are shown in Table 3.

3 A test film coated with cellulose butyrate acetate lacquer was prepared in the same manner as in Table 1, and tested for adhesion and hot water resistance. The results are shown in Table 3.

Examples 8-11 and Comparative Examples 4-6

Claims (1)

[Claims] 1. On at least one side of the polyester film, there is a general formula (I) ▲mathematical formula, chemical formula, table, etc.▼(I) (in the formula, R_1, R_2, R_3, R_4 each independently represent hydrogen, addition-polymerizable oxazoline (a) represented by halogen, alkyl, aralkyl, phenyl or substituted phenyl group, and R_5 is an acyclic organic group having an addition-polymerizable unsaturated bond; and at least one kind as necessary A polyester film comprising a coating layer formed from a coating agent containing a polymer obtained by polymerizing other monomers (b). 2. The film according to claim 1, which is a stretched polyester film. 3. At least one side of the polyester film has the general formula (
I) ▲There are mathematical formulas, chemical formulas, tables, etc.▼(I) (In the formula, R_1, R_2, R_3, R_4 are each independently hydrogen, halogen, alkyl, aralkyl, phenyl or substituted phenyl group, and R_5 is an addition polymerization It is an acyclic organic group having a sexually unsaturated bond.) Contains a polymer obtained by polymerizing addition-polymerizable oxazoline (a) represented by A method for producing a polyester film, which comprises applying a coating agent and then stretching the film.