KR20170097358A

KR20170097358A - Primer layer having improved adhesive property

Info

Publication number: KR20170097358A
Application number: KR1020160019003A
Authority: KR
Inventors: 김동민; 전용현; 원종선
Original assignee: 주식회사 효성
Priority date: 2016-02-18
Filing date: 2016-02-18
Publication date: 2017-08-28

Abstract

The present invention relates to a polyester film with improved easy adhesion properties. An optical primer layer with improved easy adhesion properties, as a primer layer with improved easy adhesion properties which is coated on a polyester film, comprises: a urethane resin in which two or more selected from the group consisting of an ester-based urethane, a carbonate-based urethane and an ether-based urethane are mixed; a curing agent; a colloid silica of 50 to 140 nm; and one or more surfactants selected from the group consisting of a fluorine-based surfactant, a silicone-based surfactant, and an alcohol-based surfactant. The present invention not only has improved the easy adhesion properties by mixing two or more from the ether-based urethane, ester-based urethane and carbonate-based urethane, thereby applying the mixture to coating, but also has secured appearance and adhesive property of the film by using the curing agent in the primer layer with improved easy adhesion properties which is coated on the polyester film.

Description

The primer layer having an improved optical adhesive property {Primer layer having improved adhesive property}

The present invention relates to a primer applied to a polyester film having improved adhesiveness and a method for producing a polyester film produced by applying the primer, wherein an ether-based, ester-based and carbonate-based polyurethane are mixed and applied to a coating To improve the adhesiveness and to secure the appearance and adhesion of the film by using a curing agent.

In general, the polyester film is excellent in dimensional stability, thickness uniformity and optical transparency, and is widely used not only for display devices but also for various industrial materials. Particularly in recent years, interest in liquid crystal display devices has been rapidly increasing, and research has been actively carried out to replace substrates of these devices with polyester films. The replacement of the polyester film with a polyester film not only reduces the weight of the display device, It is in the spotlight because it has higher productivity than organic substrate.

One of the requirements for use in this application is the adhesion to the substrate and the post-treatment coating solution.

Polyester films generally have poor adhesion to other polymeric materials and add adhesion through surface coatings. Usually, water-dispersed ester resins, acrylic resins, and polyester resins are mainly used as adhesives. However, the polyester-based resin is excellent in adhesion to a polyester-based film, but when it is subjected to post-processing such as a hard coating layer which is another substrate, the adhesion is insufficient. It is also insufficient in heat resistance and water resistance.

In recent years, urethane binders having excellent adhesion and excellent heat resistance and water resistance have been most widely used to solve the above problems.

Korean Published Patent Application No. 2013-0001261

Urethane binders have an OH group, which can be substituted with other polymers, and polyurethane molecules having various physical properties can be produced and applied. Examples thereof include ester-based urethane, carbonate-based urethane and ether-based urethane. Disclosure of Invention Technical Problem [8] Accordingly, the present invention has been made to solve the above-mentioned problems of the prior art, and it is an object of the present invention to provide a coating composition and a primer layer by using ester- The polyester having the water resistance and the heat resistance while maintaining the properties is to produce an adhesive coating film.

In order to achieve the above object, the present invention provides a primer layer improved in adhesion, which is applied to a polyester film,

Wherein the primer layer is a urethane resin in which two or more selected from the group consisting of an ester-based urethane, a carbonate-based urethane and an ether-based urethane are mixed;

Curing agent;

50 to 140 nm colloidal silica; And

The present invention provides an optical primer layer having improved adhesion, which comprises at least one surfactant selected from the group consisting of fluorine-based, silicone-based, and alcohol-based surfactants.

The curing agent is a mixture of one kind selected from the group consisting of an aziridine compound, an epoxy compound and a carbodiimide compound, which is a low-temperature curing agent that reacts at 70 ° C or less, with one kind of isocyanate compound which is a high- .

And the primer layer is applied to one side or both sides of the polyester base film.

The present invention relates to a primer layer applied to a polyester base film having excellent adhesiveness, heat resistance, and water resistance, and more particularly to a primer layer which is stable to UV and does not deteriorate adhesion by UV exposure.

Hereinafter, the present invention will be described.

The present invention relates to a primer layer having improved adhesiveness applied to a polyester film,

Curing agent;

50 to 140 nm colloidal silica; And

The primer layer of the present invention is preferably 0.01 to 2 탆. If it is less than 0.01 mu m, the adhesiveness is deteriorated. If it exceeds 2 mu m, transparency and coating properties are deteriorated.

The urethane resin used in the present invention is a urethane resin in which two or more kinds selected from the group consisting of ester-based urethane, carbonate-based urethane and ether-based urethane are mixed. The ester-based urethane resin means an ester-based polyol and isocyanate, the carbonate-based urethane resin is a carbonate-based polyol and isocyanate, and the ether-based urethane resin is a resin containing urethane units formed by reacting an ether-based polyol and isocyanate respectively .

The isocyanate may be a compound having two or more NCO groups without limitation, for example, 2,4-hexamethylene diisocyanate, 2,6-hexamethylene diisocyanate and the like.

The polyester-based polyol is synthesized by a chemical reaction with a dicarboxylic acid and a glycol. Wherein the dicarboxylic acid is selected from the group consisting of adipic acid, sebacic acid, isophthalic acid, dimethylterephthalic acid, terephthalic acid, isophthalic acid, naphthalene dicarboxylic acid, cyclohexanedicarboxylic acid, diphenoxyethanedicarboxylic acid, di Phenyl dicarboxylic acid, diphenyl ether dicarboxylic acid, anthracene dicarboxylic acid or?,? - bis (2-chloropetoxy) ethane-4,4'-dicarboxylic acid. The glycol may be at least one member selected from the group consisting of ethylene glycol, methylene glycol, tetramethylene glycol, pentamethylene glycol, hexamethylene glycol, hexylene glycol, 1,2-propylene glycol, 1,3-butanediol, Diethylene glycol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, trimethylpropane, and the like.

Examples of the ester-based polyol include polyethylene glycol, polypropylene glycol, polyoxypropylene triol, and polytetramethylene glycol.

On the other hand, the polycarbonate-based polyol can be obtained by reacting a compound having a carbonate group with a polyol component, and examples of the compound having a carbonate group include diphenyl carbonate, dialkyl carbonate, alkylene carbonate and the like.

In the case where the urethane resin used in the present invention is selected by mixing two kinds of resins selected from the group consisting of ester-based urethane, carbonate-based urethane and ether-based urethane, the ratio between the resins is preferably from 10:90 to 90:10 , Preferably 20:80 to 80:20 by weight.

When the urethane resin used in the present invention is prepared by mixing both the ester-based urethane, the carbonate-based urethane and the ether-based urethane, it is preferable that each resin is contained in a proportion of 5 to 90% by weight relative to the total urethane resin.

When the ratio is out of the above range, it is difficult to obtain the adhesive property and the appearance of the film which are the object of the present invention.

In the present invention, at least one selected from the group consisting of an aziridine compound, an epoxy compound, a carbodiimide compound, and an isocyanate compound which is a high-temperature curing agent reacting at 100 ° C or higher can be used as the curing agent, .

In the present invention, the curing agent is a mixture of one kind selected from the group consisting of an aziridine compound, an epoxy compound and a carbodiimide compound, which is a low-temperature curing agent which reacts at 70 ° C or less, with an isocyanate compound which is a high- .

Examples of aziridine compounds that can be used include N, N'-toluene-2,4-bis (1-aziridine carboxamide), N, N'-diphenylmethane-4,4'- Triethylenemelamine, bisisopropanoyl-1- (2-methyl aziridine), and tri-1-aziridinylphosphine oxide.

Examples of carbodiimide compounds that can be used include carbodiimide and polycarbodiimide.

The isocyanate curing agent which reacts at a usable temperature of 100 ° C or higher is formed by reacting an isocyanate with a blocking agent of a low molecular weight substance. Examples of the blocking agent include 3, 5-dimethylpyrazole, phenol, 2-pyridinol, N-hydroxysuccinimide, N-hydroxysuccinimide, N-hydroxysuccinimide, N-hydroxysuccinimide, N-methylpyrrolidone, 2-ethylhexylhydroxybenzoate, p-cresol formaldehyde, 2 - [(dimethylamino) thiophenol, mercaptoethanol, ) Methyl] phenol, pyrazole, 3-methylpyrazole, 1,2,4-triazole and the like can be used. Particularly, 3, 5-dimethylpyrazole is preferable.

The curing agent is preferably contained in an amount of 0.1 to 10% by weight based on the total coating liquid. If it is less than 0.1%, it is difficult to improve the adhesive strength, and if it exceeds 10% by weight, the haze of the film is increased and it is not suitable as a film.

The isocyanate compound which is a high-temperature curing agent which reacts at 100 ° C or higher with one kind selected from the group consisting of an aziridine compound, an epoxy compound and a carbodiimide compound, which is a low-temperature curing agent, When used, the ratio of the low temperature curing agent to the high temperature curing agent is preferably from 10:90 to 90:10 by weight, preferably from 20:80 to 80:20 by weight.

The colloidal silica used in the present invention is intended to improve the winding of the polyester film and to prevent blocking, and colloidal silica of 50-140 nm may be contained in an amount of 1 to 5% by weight based on the coating liquid applied to the primer layer. If the colloidal silica particles are less than 50 nm, the anti-blocking effect is deteriorated. If the colloidal silica particle exceeds 140 nm, the transparency is lowered.

The surfactant is for preventing uncoating, and may include at least one of a fluorine-based, silicone-based or alcohol-based surfactant in an amount of about 10% or less of the coating liquid applied to the primer layer.

Examples of the fluorochemical surfactant include perfluorinated acid, perfluorinated carboxylate, perfluorinated sulfonate, and the like.

As the silicone surfactant, it is preferable to include a polyether-modified polydimethylsiloxane compound. Commercially available products include BYK306, 333, 337 and 341 of BYK-Chmie.

As the alcohol surfactant, polyoxyethylene alkyl ether or the like may be used.

Example 1 -8

For the production of the polyester film constituting the primer layer of the present invention, the unstretched polyester film was used as a base film and the coating liquid for forming the primer layer was composed of 70% by weight of water, 15% by weight of an ester-based urethane binder according to Table 1 20 wt% of a mixed urethane resin aqueous dispersion containing 15 wt% of a carbonate-based urethane binder (Example 1-4) or an ether-based urethane binder (Examples 5-8), 70 wt% of water, 5% by weight of a curing agent aqueous dispersion consisting of 30% by weight of a curing agent and 63.9% by weight of water were mixed, and 1.0% by weight of a surfactant aqueous dispersion composed of 90% by weight of water and 10% by weight of a fluorine- And 70 wt% of colloidal silica particles consisting of 70 nm colloidal silica particles, and a remaining amount of water to prepare a coating liquid. Then, the coating liquid was applied to the unstretched polyester base film having a thickness of 100 mu m to prepare a polyester Le film. The application of the coating liquid was applied using a # 3 wire bar. The thickness of the adhesive layer thus produced is 0.1 mu m.

This adhesive layer constitution bookbinder Hardener A B C D E F G Comparative Example 1 O O Comparative Example 2 O O O Comparative Example 3 O O O Comparative Example 4 O O O Example 1 O O O Example 2 O O O O Example 3 O O O O Example 4 O O O O Example 5 O O O Example 6 O O O O Example 7 O O O O Example 8 O O O O

(A: ester-based urethane, B: carbonate-based urethane, C: ether-based urethane, D: an aziridine compound as a low-temperature curing agent reacting at 70 캜 or lower, E: F: a carbodiimide compound which is a low-temperature curing agent which reacts at 70 ° C or less, G: an isocyanate compound blocked with 3,5-dimethyl pyrazole which is a high-

(The proportion of the compound constituting the hardener was prepared in the same ratio)

Comparative Example 1 -4

For the production of the polyester film constituting the primer layer of the present invention, the unstretched polyester film is used as the base film and the coating liquid for forming the primer layer is a urethane resin containing 70% by weight of water and 30% by weight of ester- 20% by weight of an aqueous dispersion, 5% by weight of a curing agent aqueous dispersion composed of 70% by weight of water and 30% by weight of a curing agent according to Table 1, and 63.9% by weight of water were mixed and mixed with 90% by weight of water and 10% , 5 wt% of an inorganic particle water dispersion composed of 30 wt% of water and 70 wt% of silica particles, and the remaining amount of water to prepare a coating liquid. Then, the non-drawn To a polyester base film to prepare a polyester film. The application of the coating liquid was applied using a # 3 wire bar. The thickness of the adhesive layer thus produced is 0.1 mu m.

Experimental Method

Physical properties of the polyester films of Examples 1 to 8 and Comparative Examples 1 to 4 were measured by the following experimental examples and the results are shown in Table 2 below.

1. Adhesiveness at room temperature

The adhesion between the substrate and the primer layer of the polyester film prepared in Examples 1 to 8 and Comparative Examples 1 to 4 was measured. After exposing the polyester film coated with the primer layer to UV for 30 minutes, a prism top coating was applied to the surface to which the primer layer was adhered by using a # 20 wire bar, and then the film coated with the primer layer Cut lines are created and 1 mm x 1 mm squares are placed in a 10 x 10 matrix. A cellophane tape (No. 205, made by NICHIBAN, 24 mm wide) was attached to the cut line film, and the tape was rubbed with a velvet to strongly adhere to the polyester film, and then the tape was vertically peeled off. The area of the primer layer remaining on the adhesive layer was visually observed, and the adhesive force was calculated by the following equation (1) (average after 3 times)

Equation 1

2. Exposure to adhesive

In order to test the adhesiveness between the substrate and the primer layer of the polyester film produced in Examples 1 to 8 and Comparative Examples 1 to 4, a polyester film coated with a primer layer was coated with UV 30 Minute, a prism top coating was applied to the surface to which the primer layer was adhered by using a # 20 wire bar. After the prism top coated surface was exposed to water vapor for about 30 minutes, the water was removed and the adhesion was confirmed by the same method at room temperature.

3. Alkali-resistant adhesive

The adhesion of the alkali resistance between the substrate and the primer layer of the polyester film produced in Examples 1 to 8 and Comparative Examples 1 to 4 was measured. The polyester film coated with the primer layer was exposed to UV for about 30 minutes, and then a prism top coating was applied to the surface to which the primer layer was adhered using a # 20 wire bar. Then, the specimens were immersed in 5% aqueous NaOH solution for about 30 minutes, and the water was removed.

The adhesion (%) Room temperature expose Alkali Comparative Example 1 50 55 45 Comparative Example 2 56 60 52 Comparative Example 3 55 55 52 Comparative Example 4 45 45 40 Example 1 78 66 76 Example 2 99 98 97 Example 3 99 98 97 Example 4 99 98 97 Example 5 56 80 70 Example 6 97 98 96 Example 7 99 99 98 Example 8 99 97 96

Claims

In this primer layer having improved adhesiveness applied to a polyester film,
Wherein the primer layer comprises a urethane resin mixed with at least two selected from the group consisting of an ester-based urethane, a carbonate-based urethane and an ether-based urethane;
Curing agent;
50 to 140 nm colloidal silica; And
Wherein the surfactant is at least one selected from the group consisting of a fluorine-based, silicone-based, and alcohol-based surfactant.

The curing agent according to claim 1, wherein the curing agent is an isocyanate compound 1 which is a high-temperature curing agent which reacts with at least one selected from the group consisting of an aziridine compound, an epoxy compound and a carbodiimide compound, Wherein the primer layer is an optical primer layer having improved adhesion.

A polyester film having improved adhesion property, characterized in that the optical primer layer having improved adhesiveness according to claim 1 or 2 is applied to one side or both sides of a polyester base film.