KR101010895B1 - Protecting film coating methacrylate co-polymer and method of fabricating the same - Google Patents

Abstract

The present invention provides a protective film having excellent elongation and surface appearance and a method of manufacturing the same. The film and method are made by coating two kinds of methacrylates on a base film with a coating solution containing a copolymer of monomers and curing them. In this case, the methacrylate copolymer may be composed of 50 to 80 wt% of glycidyl methacrylate and 20 to 50 wt% of at least one monomer selected from methyl methacrylate, ethyl methacrylate and pentyl methacrylate, and has an average particle diameter. The polymethacrylate microparticles having 0.01 to 0.1 μm may be included in a proportion of 0.1 to 3 wt%.

Methacrylate, polymethacrylate, polyester, UV curing, protective film

Description

Protective film coating methacrylate co-polymer and method of fabricating the same}

The present invention relates to a protective film of a curved product and a method of manufacturing the same, and more particularly to a protective film for protecting a product having a surface shape including a curved and a method of manufacturing the same.

Recently, as the demand for small electronic products such as mobile phones, MP3 players, and PMPs soared, not only their functions but also the appearance of the products have become important. However, since the exterior material of these products is mainly plastic, it is difficult to maintain the appearance as the first time due to light, heat, scratches, and other environmental factors. Accordingly, in order to protect the inside of the product and prevent functional scratches and discoloration of the exterior, coating processes are performed to perform chemical surface treatments such as plating and deposition in order to satisfy both functionality and aesthetics.

However, solvent wastewater or volatile organic compounds (VOCs) generated during the coating process may adversely affect the ecosystem, such as harming the human body and polluting water and air even at low concentrations. Therefore, in order to solve this problem, a new process of manufacturing a printed protective film instead of the above painting process and sticking or bonding it to an injection product has been attempted.

Using a printed protective film, it is possible to reduce the environmental pollution compared to the chemical coating process. In addition, the process of using a protective film can be simplified by gluing and releasing at the same time in the four steps of conventional injection, deposition, adhesion, and attaching an aluminum name plate, thereby reducing production costs. To this end, in order to protect the product from heat, light, and other external factors, a method of coating a functional coating film on both sides based on a film of a soft material, or laminating or bonding other films or papers has been used.

However, these conventional techniques are difficult to apply to various types of injection products. Because, when the film is applied to the curved surface of the injection molded product, the elongation of the protective film is low, so that the coating film is broken or does not adhere to the phenomenon of falling. In addition, when using an ultraviolet curable resin, there is an advantage that can increase the surface hardness compared to the thermosetting resin, but it is more difficult to apply to the curved surface due to the decrease in elongation.

On the other hand, the protective film requires a variety of properties depending on the application. In some cases, application is possible only if the elongation is excellent, but there is a case where the appearance of the coating film including the elongation is simultaneously required. However, the conventional protective film is not excellent in applying the elongation characteristics to the actual product, and furthermore cannot secure the elongation and appearance of the coating film at the same time.

Therefore, the technical problem to be achieved by the present invention is to provide a protective film excellent in elongation. In addition, another technical problem to be achieved by the present invention is to provide a protective film excellent in elongation and appearance of the coating film as necessary. Furthermore, another technical problem to be achieved by the present invention is to provide a method for producing the protective film.

The protective film of the present invention for achieving the above technical problem is made by coating with a coating liquid containing a copolymer of polymerized monomers of two kinds of methacrylate on the base film is cured.

The protective film of the present invention for achieving another technical problem of the present invention is the methacrylate copolymer is selected from 50 to 80wt% of glycidyl methacrylate and methyl methacrylate, ethyl methacrylate and pentyl methacrylate It may consist of 20 to 50wt% of at least one monomer.

In the present invention, the coating liquid may include 5 to 30 wt% of the copolymer resin, and may include polymethacrylate fine particles having an average particle diameter of 0.01 to 0.1 μm at a ratio of 0.1 to 3 wt%.

The manufacturing method of the protective film of the present invention for achieving the above another technical problem is to prepare a base film first. Thereafter, a coating liquid containing a copolymer obtained by polymerizing monomers of two kinds of methacrylates is wet coated on the base film. Next, the coating liquid is cured using ultraviolet rays.

The protective film coated with the methacrylate-based copolymer of the present invention and a method of manufacturing the same are not only excellent in elongation, but also excellent in appearance of the coating film as necessary, and applied to various types of injection products having curvature, thereby injecting products from external factors. It can fully protect the appearance and inside.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described with reference to the accompanying drawings below. The embodiments described below may be modified in various forms, and the scope of the present invention is not limited to the following examples. Embodiments of the present invention are provided to provide a thorough explanation to those skilled in the art.

Embodiments of the present invention will propose a protective film and a method of manufacturing the same applied to a curved product, such as an injection product. In this case, the protective film may be divided into only requiring the elongation characteristics and requiring the coating film appearance characteristics together with the elongation. Therefore, in the embodiment of the present invention will be described by the characteristics of the protective film coated with the methacrylate copolymer.

(Examples for the protective film requiring elongation properties, the first embodiment below)

The base film used for the 1st Example of this invention is a polyester film. Polyester film is widely used for industrial purposes because of its excellent mechanical properties and environmental friendliness. In particular, polyethylene terephthalate (PET) and polyethylene naphthalate (PEN) are excellent in stability of physical properties and excellent chemical resistance in a wide range of temperature range, good surface properties and good uniformity of thickness. In addition, it has the advantage that it can be widely used for various purposes because of its excellent adaptability under various process conditions. For example, it is used for industrial use, medical use, magnetic tape, condenser, packaging, photographic film, labeling, and the like.

In the first embodiment of the present invention, a PET film was used as the polyester film. PET is transparent and easy to process on the surface. As the substrate of the present invention, the polyester film is not necessarily limited, but preferably has a tensile strength of 20 to 40 kgf / mm 2 and a thickness in the range of 50 to 150 μm. Since the physical properties of the polyester change depending on the polymerization conditions, it is preferable to synthesize the polyester under the following conditions.

Polyester polycondenses the acid component which has aromatic dicarboxylic acid as a main component, and the diol component which has alkylene glycol as a main component. Specific examples of aromatic dicarboxylic acids include dimethyl terephthalate, terephthalic acid, isophthalic acid, diphenyl etherdicarboxylic acid, cyclohexane dicarboxylic acid, diphenoxyethane dicarboxylic acid, diphenyl dicarboxylic acid, diphenylether dicarboxylic acid, anthracene dicarboxylic acid and α. , beta -bis (2-chloro phenoxy) ethane-4, 4 '-dicarboxylic acid and the like. Among these, preference is given to using dimethyl terephthalate or terephthalic acid.

Specific examples of the alkylene glycol include ethylene glycol, trimethylene glycol, tetramethylene glycol, pentamethylene glycol, hexamethylene glycol, hexylene glycol, and the like. It is preferable to use ethylene glycol among these.

The polyester of the present invention is composed of polyester, which is a homopolymer composed of ethylene terephthalate at least 60 wt%. 40 wt% or less of a diol compound (diethylene glycol, propylene glycol, neopentyl glycol, polyethylene glycol, P-xylene glycol, 1, 4-cyclohexane dimethanol, 5-sodium sulfolezocin, etc.); Dicarboxylic acids (such as adipic acid, 5-sodium sulfoisophthalic acid) or polyfunctional dicarboxylic acids (such as trimellitic acid and pyromellitic acid) can be copolymerized.

The polyester film is produced in the form of a chip by melting the polyester resin made by the above method in the form of a chip through extrusion, stretching, winding, and at least uniaxially prepared.

Subsequently, in order to produce a protective film having excellent elongation, a coating liquid including a methacrylate copolymer was applied on the base film. The ultraviolet curing step of the copolymer coating film of the present invention was not cured completely but semi-cured so as to have a constant elongation. That is, two or more kinds of methacrylates were copolymerized to satisfy elongation.

The methacrylate type forms a copolymer with a monomer having a methacrylo group as shown in the formula below, and the kinds thereof are glycidyl methacrylate (GMA), methyl methacrylate (dimethyl acrylate) (MMA), and ethyl meta. Methacrylate (EMA), pentyl methacrylate (PMA), and the like.

Surface tension of the polyester film is superior to the adhesion of 39dyne / cm or more, but can be pretreated by a physical method such as corona or chemical methods such as acrylic binder treatment in order to further improve the adhesion. All known wet coating methods are possible, but methods such as gravure roll coating, die coating, and bar coating can be used as necessary. In this case, known photoinitiators, dispersants and the like can be used within the range in which the physical properties of the protective film of the present invention are maintained.

Hereinafter, referring to Table 1, the difference in elongation between the protective film of the present invention coated with the methacrylate copolymer and the protective film coated with methacrylate and other resins is examined. Elongation was measured using an elongation measuring instrument (model name: 4206, manufacturer: Instrong Co., USA) under the conditions of ASTM D 882, an industrial standard. At this time, the average molecular weight of the methacrylate copolymer is preferably in the range of 10,000 to 25,000, the polymerization method may be a bulk polymerization, suspension polymerization, emulsion polymerization, solution polymerization and the like.

(Example 1-1)

First, 0.03 g of lauryl mercaptan, 25 g of butyl acetate, 2,2-azobisisobutyronitrile in 30 g of a mixture of 60 wt% of glycidyl methacrylate (GMA) and 40 wt% of methyl methacrylate (MMA) 0.15 g of reel (2,2-azobis-isobutyronitrile; AIBN) is added thereto, heated to a temperature of 90 ° C., and then continuously supplied with nitrogen to stabilize for 1 hour at the above temperature conditions. Next, a mixture of 0.09 g of loryl multantan and 0.5 g of AIBM was added to 20 g of a mixture of 64 wt% of GMA and 36 wt% of MMA. To stabilize for 3 hours. 0.3 g of AIBN was added thereto and stirred at 90 ° C. for 1 hour, and then heated to 120 ° C. and stirred for 2 hours. And it cools to 60 degreeC.

5 g of acrylic acid, 0.03 g of mesoquinone, and 0.2 g of triphenylphosphine (PPh) were added to the material thus synthesized, instead of nitrogen, and stabilized for 8 hours by raising the temperature to 110 ° C. Let's do it. Finally, 0.03 g of mesoquinone is further added to suppress the polymerization reaction.

The copolymer obtained through the three-step reaction process is mixed with ethyl acetate solvent at 20wt% to form a coating solution. The coating liquid prepared by the above method is applied onto a PET film having a thickness of 120 μm at a speed of 150 m / min using the microgravure roll method. The curing apparatus used in the curing process is equipped with four ultraviolet lamps having a 254 nm dominant wavelength and is designed so that the film stays for 5 seconds. The elongation of the film produced by the above procedure was 2.5%.

(Examples 1-2 to 1-5)

A copolymer was prepared in the same manner as in Example 1-1, but when the ratio was 30 wt% GMA and 70 wt% MMA, the elongation of the film was 3.5% (Example 1-2), and the GMA 35 wt% and MMA 65 wt% When the ratio is elongation is 1.5% (Example 1-3), when the ratio of GMA 85wt%, MMA 15wt%, the elongation is 0.7% (Example 1-4), GMA 45wt%, MMA 55wt% When the ratio was set, the elongation was 1.5% (Example 1-5).

(Comparative Example 1-1 and Comparative Example 1-2)

A copolymer was prepared in the same manner as in Example 1-1, except that the copolymerized monomer was 65 wt% of GMA and 35 wt% of styrene, or the copolymerized monomer was composed of 65 wt% of styrene and 35 wt% of propylene. When the ratio was set, the elongation of the film did not appear.

TABLE 1

division Copolymer Properties ingredient ratio
(wt%) ingredient ratio
(wt%) % Elongation

Example
One
1-1 GMA 64 MMA 36 2.5 1-2 GMA 30 MMA 70 3.5 1-3 GMA 35 MMA 65 1.5 1-4 GMA 85 MMA 15 0.7 1-5 GMA 45 MMA 55 1.5 Comparative example
One 1-1 GMA 65 styrene 35 0.0 1-2 styrene 65 propylene 35 0.0

* GMA: glycidyl methacrylate

* MMA: Methyl Methacrylate

It can be seen that the elongation of the protective film using the methacrylate copolymer is high. Specifically, even when the GMA is mixed in a ratio of 30 to 85 wt%, the elongation of the protective film was 0.7 to 3.5%. However, when styrene or propylene is used as the copolymer, elongation could not be secured. Therefore, according to the first embodiment of the present invention, the protective film of the present invention can be applied to products requiring elongation.

(Examples of Protective Films Requiring Elongation Characteristics, Surface Hardness, and Coating Film Appearance Properties, Second Embodiment Hereinafter)

The process for producing the substrate, copolymer and protective film used in the second embodiment is the same as the first embodiment. However, the difference from the first embodiment is to limit the mixing ratio of the copolymer and the amount of PMMA fine particles added to the coating film in order to satisfy the surface hardness, elongation and appearance of the coating film at the same time.

When the fine particles are mixed with the coating liquid and applied to the film, not only the surface hardness can be kept constant, but also the phenomenon of the film falling off during the winding and unwinding of the film can be suppressed. The fine particles may be any known particles having a particle diameter of 0.01 to 0.1 mu m, but in particular, it is preferable to use polymethacrylate (PMMA) (melting point: 340 to 460 DEG C) having excellent compatibility with the methacrylate polymer.

Hereinafter, referring to Table 2, the surface hardness, elongation, and coating film appearance characteristics of the fine particles of the present invention to which the methacrylate copolymer is applied will be described. At this time, the surface hardness of the present invention was measured using a pencil hardness tester (model name: 221-D, manufacturer: ITOH, Japan). Specifically, the pencil of 6B-9H is measured while contacting the film surface at an angle of 45 kPa, and the hardness grade of the pencil damaging the film surface becomes the hardness value of the film surface. The same sample was repeatedly measured five times under the same conditions and determined as an average value. The average surface hardness is 2H or more.

Elongation was measured by using an elongation measuring device (model name: 4206, manufacturer: Instrong Co., USA) under the conditions of ASTM D 882. The appearance of the coating film was evaluated by the dispersion state and the protrusion generation state of the coating film, and the surface state was observed under a microscope to evaluate the dispersibility by the observed number of protrusions per area of 10 cm × 10 cm. If the number of protrusions is one or less, the evaluation is good.

(Example 2-1)

In the same manner as in Example 1-1, a copolymer was prepared with a copolymer of GMA 64 wt% and MMA 36 wt%, and then mixed with ethyl acetate solvent at 20 wt% of a copolymer, and having a particle diameter of 0.08 μm. ) 0.5 wt% of the fine particles to prepare a coating liquid. The method of coating and curing the prepared coating solution on a PET film is carried out in the same manner as in Example 1-1. From the physical properties of the film produced by the above method, the glass transition temperature of the copolymer was 162 占 폚, the thickness of the coating film was 2.8 µm, the surface hardness was 2.3H, the elongation was 2.5%, and the appearance of the coating film was good.

(Example 2-2)

The protective film manufacturing process was the same as in Example 2-1, and the copolymer ratio was 55 wt% of GMA and 45 wt% of MMA, and PMMA having a particle size of 0.08 μm was used at a concentration of 0.8 wt% in a solvent. At this time, the glass transition temperature of the copolymer was 155 ° C, the thickness of the coating film was 1.7 µm, the surface hardness was 2.9H, the elongation was 2.3%, and the appearance of the coating film was good.

(Example 2-3)

The protective film production process is the same as in Example 2-1, the copolymer ratio is 75 wt% of GMA, 25 wt% of PMA, and PMMA having a particle size of 0.06 μm is used at a concentration of 1.7 wt% in a solvent. At this time, the glass transition temperature of the copolymer was 168 ° C, the thickness of the coating film was 3.1 µm, the surface hardness was 2.1H, the elongation was 3.3%, and the appearance of the coating film was good.

(Example 2-4)

The protective film manufacturing process is the same as in Example 2-1, and the copolymer ratio is 60 wt% of GMA, 40 wt% of MMA, and PMMA having a particle size of 0.04 µm is used at a concentration of 0.2 wt% in a solvent. At this time, the glass transition temperature of the copolymer was 159 ° C, the thickness of the coating film was 5.0 µm, the surface hardness was 2.5H, the elongation was 2.1%, and the appearance of the coating film was good.

(Example 2-5)

The protective film manufacturing process was the same as in Example 2-1, and the copolymer ratio was 53 wt% of GMA and 47 wt% of MMA, and PMMA having a particle size of 0.02 µm was used at a concentration of 2.8 wt% in the solvent. At this time, the glass transition temperature of the copolymer was 152 ° C, the thickness of the coating film was 1.1 µm, the surface hardness was 3.1H, the elongation was 4.1%, and the appearance of the coating film was good.

(Comparative Example 2-1)

The protective film production process is the same as in Example 2-1, the copolymer ratio is 85 wt% of GMA, 15 wt% of MMA, and PMMA having a particle diameter of 0.05 μm is used at a concentration of 0.7 wt% in a solvent. At this time, the glass transition temperature of the copolymer was 175 ° C, the thickness of the coating film was 3.1 μm, the surface hardness was 3.8H, the elongation was 0.5%, and the appearance of the coating film was poor.

(Comparative Example 2-2)

The protective film production process is the same as in Example 2-1, the ratio of the copolymer is GMA 60wt%, EMA 40wt%, PMMA having a particle size of 0.3㎛ is used as a concentration of 4.5wt% in the solvent. At this time, the glass transition temperature of the copolymer is 161 ℃, the thickness of the coating film is 3.9㎛, the surface hardness is 2.6H, the elongation is 0.3% and the appearance of the coating film was poor.

(Comparative Example 2-3)

The protective film manufacturing process was the same as in Example 2-1, and the copolymer ratio was 53 wt% of GMA and 47 wt% of PMA. As the fine particles, silica having a particle diameter of 0.1 μm was used at a concentration of 0.3 wt% in the solvent. do. At this time, the glass transition temperature of the copolymer was 154 ° C, the thickness of the coating film was 2.9 µm, the surface hardness was 2.1H, the elongation was 0.8%, and the appearance of the coating film was poor.

(Comparative Example 2-4)

The protective film manufacturing process was the same as in Example 2-1, and the copolymer ratio was 45 wt% of GMA and 55 wt% of MMA, and PMMA having a particle size of 0.09 μm was used at a concentration of 0.6 wt% in a solvent. At this time, the glass transition temperature of the copolymer was 150 ° C, the thickness of the coating film was 0.6 µm, the surface hardness was 1.0H, the elongation was 3.4%, and the appearance of the coating film was normal.

TABLE 2

division
Example 2 Comparative Example 2 2-1 2-2 2-3 2-4 2-5 2-1 2-2 2-3  2-4 Public
coalescence

ingredient GMA GMA GMA GMA GMA GMA GMA GMA GMA Ratio wt% 64 55 75 60 53 85 60 53 45 ingredient MMA EMA PMA MMA MMA MMA EMA PMA MMA Ratio wt% 36 45 25 40 47 15 40 47 55 Coating liquid


Public
coalescence t _g
(℃) 162 155 168 159 152 175 161 154 150 ratio
wt% 20 16 25 7 29 23 49 25 32 Particulate
ingredient PMMA PMMA PMMA PMMA PMMA PMMA PMMA silica PMMA Particle diameter㎛ 0.08 0.08 0.06 0.04 0.02 0.05 0.3 0.1 0.09 ratio
wt% 0.5 0.8 1.7 0.2 2.8 0.7 4.5 0.3 0.6 film
Properties

Coating film thickness μm 2.8 1.7 3.1 5.0 1.1 3.1 3.9 2.9 0.6 Surface Hardness H 2.3 2.9 2.1 2.5 3.1 3.8 2.6 2.1 1.0 Elongation% 2.5 2.3 3.3 2.1 4.1 0.5 0.3 0.8 3.4 Coating film appearance Good Good Good Good Good Bad Bad Bad Bad

* PMMA: Polymethacrylate

As shown, when the polymerization ratio of the glycidyl methacrylate is 80wt% or more, the glass transition temperature of the copolymer is increased to 170 ℃ or more showed a relatively low elongation. Therefore, when the protective adhesion, adhesion to the curved surface of the injection molded product appeared to fall off the substrate. In addition, when the polymerization ratio of the glycidyl methacrylate is 50wt% or less, the elongation is good, but the surface strength is poor, so that the product cannot be sufficiently protected from external factors.

In addition, the concentration of the fine particles in the coating solution is 0.1 to 3wt%. If it is 0.1 wt% or less, the mixing effect of this invention cannot be acquired, and if it is 3 wt% or more, the elongation of a film will fall. Moreover, the particle diameter of microparticles | fine-particles has the preferable range of 0.01-0.1 micrometer. If it is smaller than 0.01 mu m, there is no mixing effect. If it is larger than 0.1 mu m, projections occur on the surface of the coating film, resulting in poor appearance. The elongation was relatively low even when the fine particles were made of silica rather than PMMA.

Claims (8)

5 to 30 wt% of methacrylate copolymer resin consisting of 50 to 80 wt% of glycidyl methacrylate and at least one monomer selected from methyl methacrylate, ethyl methacrylate and pentyl methacrylate to 20 to 50 wt% A protective film comprising a methacrylate copolymer coated with a coating liquid containing polymethacrylate particles having an average particle diameter of 0.01 to 0.1 μm in a ratio of 0.1 to 3 wt%. The protective film coated with a methacrylate copolymer according to claim 1, wherein the base film is a polyester film. delete The protective film coated with a methacrylate copolymer according to claim 1, wherein the copolymer has a glass transition temperature of 150 to 170 ° C. delete Preparing a base film; 5 to 30 wt% of methacrylate copolymer resin consisting of 50 to 80 wt% of glycidyl methacrylate and 20 to 50 wt% of at least one monomer selected from methyl methacrylate, ethyl methacrylate and pentyl methacrylate; Wet coating the base film with a coating liquid comprising a polymethacrylate fine particles having an average particle diameter of 0.01 to 0.1㎛ in a ratio of 0.1 to 3wt%; And Method of producing a protective film coated with a methacrylate copolymer comprising the step of curing the coating liquid using ultraviolet light. delete delete