JPH082979B2 - Polyester film and method for producing the same - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a polyester film having a coating layer and having improved surface properties, and a method for producing the polyester film.

[Problems to be improved by conventional technology and invention]

Polyester film is used for magnetic materials, packaging materials, electric
It is widely used in the fields of electronic materials and printing materials, and a surface coating layer such as a coating layer, a printing ink layer or a metal deposition layer is provided in order to give the film an aesthetic appearance and various functions according to these applications. Has been.

In a polyester film having such a surface coating layer (hereinafter referred to as a surface coating polyester film), it is important that the adhesiveness between the surface coating layer and the polyester film is secured under the usage conditions of each application. In order to improve the adhesiveness, an anchor coat layer or a primer layer coated with a solution or dispersion of polyurethane resin, polyester resin, acrylic resin or the like is usually provided. However, at present, there is still no surface-coated polyester film which is satisfactory in terms of adhesiveness, water resistance and weather resistance.

Therefore, an object of the present invention is to provide a polyester film having a coating layer suitable for obtaining a surface-coated polyester film excellent in adhesiveness and water resistance, and an industrially advantageous production method thereof. .

[Means and Actions for Solving the Problems]

The present inventors have found that a polyester film having a coating layer containing a polymer derived from a monomer containing an addition-polymerizable oxazoline as an essential component can achieve the above-mentioned object, and arrived at the present invention. Further, it was found that the target polyester film can be industrially easily produced more effectively than the conventionally known coating agent by applying a coating agent containing the polymer to the polyester film and then performing a stretching operation. Has reached the present invention.

That is, the present invention provides that at least one surface of the polyester film has the general formula (I) (In the formula, R ₁ , R ₂ , R ₃ and R ₄ are each independently hydrogen, halogen, alkyl, aralkyl, phenyl or a substituted phenyl group, and R ₅ is an acyclic organic group having an addition polymerizable unsaturated bond. A coating layer formed by a coating agent containing a polymer obtained by polymerizing the addition-polymerizable oxazoline (a) represented by the formula (1) and optionally at least one other monomer (b). The present invention relates to a polyester film characterized by having:

The present invention also provides a polyester film having at least one surface of the general formula (I). (In the formula, R ₁ , R ₂ , R ₃ and R ₄ are each independently hydrogen, halogen, alkyl, aralkyl, phenyl or a substituted phenyl group, and R ₅ is an acyclic organic group having an addition polymerizable unsaturated bond. A coating agent containing a polymer obtained by polymerizing an addition-polymerizable oxazoline (a) represented by the formula (1) and optionally at least one other monomer (b) is applied, and then the film is stretched. The present invention relates to a method for producing a polyester film, which is characterized by carrying out operations.

The addition-polymerizable oxazoline (a) used in the present invention is represented by the above general formula (I),
Specific examples include 2-vinyl-2-oxazoline, 2-
Vinyl-4-methyl-2-oxazoline, 2-vinyl-
5-methyl-2-oxazoline, 2-isopropenyl-
2-oxazoline, 2-isopropenyl-4-methyl-
2-oxazoline, 2-isopropenyl-5-ethyl-
2-oxazoline etc. can be mentioned, and these 1 type or a mixture of 2 or more types can be used. Among them, 2-isopropenyl-2-oxazoline is industrially easily available and suitable.

The other monomer (b) used in the present invention is not limited as long as it is a monomer copolymerizable with the addition-polymerizable oxazoline (a), and examples thereof include methyl (meth) acrylate, butyl (meth) acrylate, ( (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) acrylonitrile; (meth) Unsaturated amides such as acrylamide and 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; vinyl chloride; Halogen-containing α, β-saturated vinylidene chloride, vinyl fluoride, etc. Monomers; styrene, alpha such as α- methylstyrene, etc. can be mentioned β- unsaturated aromatic monomers, can be used one kind of them or a mixture of two or more.

In order to obtain a polymer using the addition-polymerizable oxazoline (a) 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 such as a method in which a polymerization catalyst, water, a surfactant and a monomer are mixed together for polymerization, a monomer dropping method, a multi-stage polymerization method, a pre-emulsion method and the like can be adopted. As the polymerization catalyst, a conventionally known one can be used, for example, hydrogen peroxide, potassium persulfate, 2,
Typical radical polymerization initiators such as 2'-azobis (2-amidinopropane) dihydrochloride can be mentioned. Also,
Examples of the surfactant include conventionally known anionic, nonionic, cationic and amphoteric surfactants and reactive surfactants. The polymerization temperature is usually 0 to
The temperature is 100 ° C., preferably 50 to 80 ° C., and the polymerization time is usually 1 to 10 hours.

Examples of the solvent that can be used when the solution polymerization method is used include toluene, hexane, methyl ethyl ketone, ethyl cellosolve, ethyl acetate, isopropyl alcohol, and the like. One or a mixture of two or more of these can be used. Can be used. Examples of the polymerization initiator include ordinary radical polymerization initiators such as azobisisobutyronitrile and benzoyl peroxide. The reaction temperature is from room temperature to 200 ° C, preferably 40 to 120 ° C
Range.

When a polymer is obtained by using the addition-polymerizable oxazoline (a) and optionally other monomer (b), the amount of the addition-polymerizable oxazoline (a) used is 0.5
It can be appropriately determined within the range of not less than wt%. When the amount of addition-polymerizable oxazoline (a) used is less than 0.5% by weight, it becomes difficult to form a coating layer having good adhesion from the resulting polymer, and as a result, a polyester film having excellent water resistance and adhesiveness is obtained. Is difficult to obtain. Also,
Considering the compatibility with other resins and the economical efficiency when the obtained polymer is mixed with another coating resin to form a coating agent, the addition-polymerizable oxazoline (a) is used in an amount of 80% by weight based on all monomers. % Or less, and the rest is preferably selected from other monomers and used for polymerization. The polymer thus obtained can be obtained, for example, in the form of an aqueous dispersion by the emulsion polymerization method or in the form of an organic solvent solution by the solution polymerization method, and these polymers can be used as they are as a coating agent.

Further, it can be used in combination with a conventionally known polyurethane resin, polyester resin, acrylic resin or the like as a coating agent. When another coating resin is used in combination, the ratio of the polymer to the known resin is preferably 1/100 or more, more preferably 10/100 or more. When the ratio of the polymer derived from the addition-polymerizable oxazoline (a) is less than 1/100, a coating agent having excellent adhesion to a polyester film may not be obtained depending on the type of known resin used in combination. . Further, if necessary, other known substances capable of controlling light absorption / transmission, lubricants, antistatic agents, water repellents, cross-linking agents, pH adjusting agents, wetting agents, viscosity adjusting agents, etc. are added to the coating agent. Alternatively, it may be appropriately diluted with water or a solvent.

Examples of the polyester resin as a base material of the polyester film of the present invention include dihydric alcohols such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene-2,6-naphthalene dicarboxylate, and aromatic dibasic acids or esters thereof. The thermoplastic polyester resin obtained from can be used.

There is no particular limitation on the method for producing a polyester film having a coating layer of the present invention, a roll coater, a gravure coater, a spray, a film produced by a molding method such as a melt extrusion method or a solution casting method by a conventional method. It can be produced by applying a coating agent using a known coating device such as an air knife coater or a curtain coater so as to have a predetermined film thickness, and drying.

In particular, in order to improve the surface properties of the polyester film as a base material and to form a required minimum thin film excellent in water resistance and adhesiveness, for example, a polyester film which has been melt extruded and has not been stretched is coated with a coating agent. Is advantageously applied by a method of applying (1) and then completing the stretching to a predetermined draw ratio (in-line coating method). Here, the unstretched polyester film includes a non-stretched film, a uniaxially stretched film stretched only in one direction, a low-stretched stretched film having a stretch ratio lower than a predetermined ratio, and the like. A particularly preferred manufacturing method in terms of economy and quality of the coating layer is that the melt-extruded polyester resin is stretched to a predetermined ratio in the vertical direction, then the coating agent of the present invention is applied, and then stretched to a predetermined ratio in the horizontal direction, This is a method of heat fixing.

In the present invention, the form of the coating agent is typically the above-mentioned aqueous dispersion or organic solvent solution, but when the film of the present invention is produced by the in-line coating method, the aqueous dispersion is easy to handle. Liquids are preferred.

〔The invention's effect〕

The polyester film of the present invention is a coating layer formed by a coating agent containing a polymer obtained by polymerizing an addition-polymerizable oxazoline (a) and optionally at least one other monomer (b). In order to have the following, various coating agents, inks,
Since the metal vapor deposition film has excellent adhesiveness, it can be widely and effectively used as a magnetic recording material, packaging material, electrical / electronic-related material, plate-making / printing material, and photographic film material.

〔Example〕

Hereinafter, the present invention will be described in detail with reference to Examples, but the scope of the present invention is not limited to these Examples. In the examples, unless otherwise indicated,% means% by weight, and part means part by weight.

Reference Example 1 A flask equipped with a stirrer, a reflux condenser, a nitrogen inlet tube, a thermometer and a dropping funnel was charged with 782.4 parts of deionized water and Hitenol N-08 (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) 15% aqueous solution. Charge 128 parts, pH 9 with an appropriate amount of ammonia water (28%)
Adjust to ~ 9.5, 70 ° C while slowly flowing nitrogen gas
Heated to. 64 parts of a 5% aqueous solution of potassium persulfate was injected into it, followed by the previously prepared butyl acrylate 13
9.5 parts, styrene 436.5 parts and 2-isopropenyl-2
-64 parts of oxazoline monomer mixture was added dropwise over 3 hours. During the reaction, nitrogen gas was continuously blown in and the internal temperature was 70 ± 1.
Kept at ℃. After keeping the same temperature for 2 hours after the dropping,
The internal temperature was raised to 80 ° C. and stirring was continued for 1 hour to complete the reaction. After cooling, an aqueous resin dispersion [1] having a nonvolatile content of 39.8% was obtained.

Reference Examples 2 to 3 In Reference Example 1, the composition of the polymerizable monomer mixture is first
Aqueous resin dispersions [2] and [3] were obtained by repeating the same operation as in Reference Example 1 except that the conditions shown in the table were used.

Reference Example 4 A flask similar to that of Reference Example 1 was charged with 200 parts of ethyl acetate, 16.9 parts of styrene, 13.1 parts of butyl acrylate and 30 parts of 2-isopropenyl-2-oxazoline, and heated to 80 ° C. while gently flowing nitrogen gas. did. Inject 36 parts of 10% ethyl acetate solution of azobisisobutyronitrile,
Subsequently, a previously prepared monomer mixture of 67.7 parts of styrene, 52.3 parts of butyl acrylate and 120 parts of 2-isopropenyl-2-oxazoline was added dropwise over 2 hours. Nitrogen gas is continuously blown in during the reaction and the internal temperature is 80 ℃ ± 1 ℃.
I kept it. After the dropping was completed, 36 parts of an azobisisobutyronitrile 10% ethyl acetate solution was added dropwise over 4 hours while maintaining the same temperature. Then, the mixture was further stirred for 1 hour to complete the reaction and then cooled to obtain a resin solution [1] having a nonvolatile content of 53.7%.

Comparative Reference Example 1 A comparative aqueous resin dispersion [1] was obtained by repeating the same procedure as in Reference Example 1, except that the composition of the polymerizable monomer mixture was changed as shown in Table 1 in Reference Example 1. .

Example 1 Kuraray Poval 117 (Kuraray Co., Ltd., polyvinyl alcohol) was added to the aqueous resin dispersion [1] obtained in Reference Example 1.
After adding 20 parts of a 5% 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]. .

The coating agent [1] was applied to a biaxially stretched polyethylene terephthalate film (PET film) having a thickness of 10 μm using a bar coater so that the dry film thickness would be 2 μm.
The PET film having a coating layer was obtained by heating at 0 ° C. for 1 minute.

Cellulose acetate lacquer (40% non-volatile content) was applied to a PET film having a coating layer and an untreated PET film to a dry film thickness of 5μ using a bar coater and dried at 110 ° C for 1 minute for testing. I got a film for it.

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

Adhesion: After applying cellophane tape to the coating surface
It was peeled off at once in the 90 ° direction, and 10 points (no peeling) to 1 point (total peeling) were evaluated according to the degree of peeling of the coating layer.

Hot water resistance: The coated PET film was dipped in hot water at 90 to 95 ° C for 30 minutes, wiped off the water on the surface, and tested for adhesion 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], 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 carried out in the same manner as in Example 1. The results are shown in Table 2.

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], 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 carried out in the same manner as in Example 1. The results are shown in Table 2.

Comparative Example 1 A comparative coating agent [1] was obtained by using the comparative aqueous resin dispersion [1] obtained in Comparative Reference Example 1 instead of the aqueous resin dispersion [1] used in Example 1. 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 carried out in the same manner as in Example 1. The results are shown in Table 2.

Example 4 To 22.1 parts of Bayronal (water-dispersible polyester manufactured by Toyobo Co., Ltd., nonvolatile content 35%) was added 87.9 parts of the aqueous resin dispersion [1] obtained in Reference Example 1. Then, after adding 20 parts of a 5% aqueous solution of Kuraray Poval 117 (manufactured by Kuraray Co., Ltd.) to 100 parts of the nonvolatile content in the obtained aqueous dispersion,
Deionized water was added to adjust the nonvolatile content to 3% to obtain a coating agent [4]. Coating agent of Example 1 [1]
A test film was obtained by repeating the same procedure as in Example 1 except that the coating agent [4] was used instead of.

Using the obtained test film, the adhesion and hot water resistance tests were carried out in the same manner as in Example 1. The results are shown in Table 2.

Example 5 Instead of the water-dispersible polyester used in Example 4, 22.1 parts of Merci 585 (manufactured by Toyo Polymer Co., Ltd., water-dispersible polyurethane, nonvolatile content 35%) was used to obtain a coating agent [5]. Using this coating agent [5], 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 carried out in the same manner as in Example 1. The results are shown in Table 2.

Comparative Example 2 The same procedure as in Example 4 was repeated except that the aqueous resin dispersion [1] was not added to the water-dispersible polyester to obtain a comparative coating agent [2]. Using this comparative coating agent [2], a test film was prepared in the same manner as in Example 1 and tested for its adhesion and hot water resistance. 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 tested for its adhesion and hot water resistance. The results are shown in Table 2.

Example 6 Ethyl acetate was added to the resin solution [1] 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 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 7 Using the coating agent [1] obtained in Example 1, a PET film having a coating layer was produced by the in-line coating method described below.

In-line coating method: Polyethylene terephthalate is melt extruded, cast on a cooling rotary drum, and then stretched 3.5 times in the extrusion direction (vertical direction), and then a coating agent is applied by a roll coater, and then 105 ° C.
Was laterally (horizontally) stretched 3.5 times and heat-set at 200 ° C. to obtain a PET film having a coating layer with a film thickness of about 12 μm and a coating layer thickness of about 0.05 μm.

A test piece (15 × 20 cm) was cut out from the obtained PET film having a coating layer, and a test film coated with cellulose butyrate acetate racker was prepared in the same manner as in Example 1 to test the adhesion and hot water resistance. I went. The results are shown in Table 3.

Examples 8-11 and Comparative Examples 4-6 Instead of using the coating agent [1] in Example 7, the coating agents [2]-[5] obtained in Examples 2-5 and Comparative Examples 1-3 and The same operation as in Example 7 was repeated except that each of the comparative coating agents [1] to [3] was used, and PET having a coating layer was used.
A film was produced.

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

Continuation of the front page (51) Int.Cl. ⁶ Identification number Reference number within the agency FI Technical display location B29L 9:00 C08L 67:00 (72) Inventor Masashi Izumibayashi 5-8 Nishimitabicho Suita City Osaka Prefecture In the Central Research Laboratory of Nippon Shokubai Chemical Industry Co., Ltd. (72) Inori Sano, No. 5-8 Nishimitabicho, Suita City, Osaka Prefecture In the Central Research Laboratory of Nippon Shokubai Chemical Industry Co., Ltd. (56) Reference JP-A-62-156140 (JP, A) JP-A-59-49242 (JP, A)

Claims (3)

[Claims] 1. A film of the general formula (I) on at least one side of a polyester film. (In the formula, R ₁ , R ₂ , R ₃ and R ₄ are each independently hydrogen, halogen, alkyl, aralkyl, phenyl or a substituted phenyl group, and R ₅ is an acyclic organic group having an addition polymerizable unsaturated bond. A coating layer formed by a coating agent containing a polymer obtained by polymerizing the addition-polymerizable oxazoline (a) represented by the formula (1) and optionally at least one other monomer (b). A polyester film having: 2. A stretched polyester film.
The described film. 3. A polyester film having the general formula (I) on at least one side thereof. (In the formula, R ₁ , R ₂ , R ₃ and R ₄ are each independently hydrogen, halogen, alkyl, aralkyl, phenyl or a substituted phenyl group, and R ₅ is an acyclic organic group having an addition polymerizable unsaturated bond. A coating agent containing a polymer obtained by polymerizing an addition-polymerizable oxazoline (a) represented by the formula (1) and optionally at least one other monomer (b) is applied, and then the film is stretched. A method for producing a polyester film, which comprises performing an operation.