TW201934597A - Acryl film - Google Patents

Abstract

The present invention relates to an acryl film produced by controlling the amount of a residual solvent by adding a specific additive and provides an acryl film including: an acryl resin consisting of 70 to 96 parts by weight of methyl methacrylate units and 4 to 30 parts by weight of alkyl (meth) acrylate units excluding methyl methacrylate; and one selected from the group consisting of an aromatic ester-based additive, a phenol-based additive, and an acryl-based additive, wherein the acryl film is prepared by a solvent casting method, and the amount of the additive to be added is 1 to 10% by weight based on 100% by weight of a main dope solution containing the acryl resin, the additive and a solvent.

Description

Acrylic film

The present invention relates to an acrylic film which is produced by adding a specific additive to control the amount of a residual solvent.

Recently, a liquid crystal display (LCD) having a low energy consumption, a low operating voltage, and a light and thin film is widely used in information display devices such as mobile phones, personal digital assistant computer monitors, televisions, and the like. The display device according to the application requires reliability in a severe environment. For example, LCD monitors used in car navigation systems require strict temperature and humidity conditions compared to monitors used in conventional televisions or personal computers because the temperature and humidity of the car may become very high. In addition, in In a liquid crystal display, a polarizer is used for indication, and since the liquid crystal display requires strict temperature and humidity conditions, a polarizer including it needs to have high durability.

Polarizers usually have a layered structure of a transparent protective film that includes a polyvinyl alcohol-based resin with a dichroic pigment that absorbs and orients on both or one side of the polarizing film. In addition, triacetyl cellulose (TAC) is generally used in a protective film, and the protective film is adhered to a polarizing film via an adhesive containing an aqueous solution of a polyvinyl alcohol-based resin. However, due to the high water vapor permeability of triacetyl cellulose, the layered protective film of a polarizer containing triacetyl cellulose will degrade the performance of the polarizer when used for a long time in a high humidity and high temperature environment. Or peeling may occur between the protective film and the polarizing film. In order to solve this problem, an acrylic resin film having a lower water vapor permeability is used as a protection for the polarizer compared with a triacetyl cellulose film. Protective film.

Existing acrylic protective films are manufactured by the melt casting method, and when manufactured by the solvent casting method, they have environmental advantages such as film, mass production, and resin recycling. The solvent casting method is a method of preparing a film by doping, extruding into a T-die when an acrylic resin is dissolved in a solvent, and drying the solvent in a tape. Although it is necessary to add optimized particles, increase the pulse intensity, and ensure the slippage of the carrying film, the process described above is possible. In particular, it is important to control the amount of residual solvent, because the amount of solvent remaining on the film is an important factor of sliding performance.

Korean Patent No. 1265007 discloses an adhesive polarizer, which does not cause light leakage of the image display unit when the use environment changes, and discloses an acrylic polymer including an adhesive layer. The acrylic polymer contains The amount of (meth) acrylate monomer units with a directional ring structure is also disclosed to determine its content according to the photoelasticity factor X of the transparent protective film, and it is also revealed that the phase difference in the transparent protective film due to environmental changes such as heating In case of change, it is recommended to adjust the adhesive layer to produce a change in the phase difference of the opposite criterion of the transparent protective film.

Korean Patent No. 1114354 discloses a protective film of an optical member having a photopolymerizable acrylic polymer, an antistatic agent, and an adhesive layer containing a polymerization initiator composition. In the photopolymerizable acrylic polymer, a photoactivator is introduced, which is capable of performing a crosslinking reaction via a radical generated in the initiator and in a composition containing a polymerization initiator in a desired proportion, In addition, by mixing an appropriate amount of antistatic agent, the aging process can be omitted during hardening, and a protective film that can simplify the manufacturing process is disclosed, and its antistatic performance is excellent during peeling or use.

Korean Patent Publication No. 2015-0061591 discloses a technology for preparing a polarizer protective film, which has excellent interlayer adhesion and non-uniform resistance due to wind, and has the use of cyclic aliphatic hydrocarbons and ethylene unsaturation. A first functional layer formed by a double bond compound. And on it, using a composition comprising a urethane acrylate, and using it on the first functional layer A second functional layer formed by a fluorinated aliphatic copolymer having a certain structure.

Japanese Patent Laid-Open No. 2014-240905 discloses a technique for producing a polarizer having excellent adhesion, reworkability, flatness, and visibility, and the thickness and elastic coefficient of the film are within certain ranges, and in the polarizer A protective film A having an acrylic resin as a main component and a retardation film B of a cellulose derivative having a substituent combined with an ether, a glucose frame as a main component are sequentially laminated, and the films A and B are UV-curable adhesives Connected.

Therefore, when producing the acrylic protective film by the solvent casting method, there is still a need to improve the technology for ensuring the sliding property of the transfer film.

(Patent Document 1) Korean Patent Publication No. 1265007

(Patent Document 2) Korean Patent Publication No. 1114354

(Patent Document 3) Korean Patent Publication No. 2015-0061591

(Patent Document 4) Japanese Patent Publication No. 2014-240905

The present invention is intended to solve the above-mentioned problems, and an object thereof is to provide acrylic acid having good quality. Since the amount of the residual solvent can be easily controlled by adding a compound having a unique structure of an acrylic resin when manufacturing an acrylic film, It is possible to prevent deterioration in quality that occurs at the time of peeling due to the amount of the residual solvent.

An acrylic film according to an embodiment of the present invention includes: an acrylic resin consisting of 70 to 96 parts by weight of a methyl methacrylate unit, and 4 to 30 parts by weight of (except methyl (meth) acrylate) ( (Meth) acrylic acid alkyl ester units; and an additive selected from the group consisting of aromatic ester-based additives, phenol-based additives, and acrylic-based additives, wherein the acrylic film is prepared by a solvent casting method, and The additive is added in an amount of 1 to 10% by weight, and is calculated based on 100% by weight of a main doping solution containing an acrylic resin, an additive, and a solvent.

The aromatic ester-based additive may have one represented by the following Chemical Formula 1, 2, 3, or 4 structure.

(Wherein X1 and X2 in Chemical Formula 1 are hydrocarbon groups containing 1-20 carbon atoms of an ester group, an ether group, or a carbonyl group, and n is 1 or more, and m, n, and l in Chemical Formula 2 are each 1 or more, m and n in Chemical Formula 3 are each 1 or more, and m in Chemical Formula 4 is 1 or more.)

The phenol-based additive may have a structure represented by the following Chemical Formula 5.

(Wherein R1 to R5 are each independently a hydrogen atom, a halogen atom, a hydroxyl group, or a hydrocarbon group having 1 to 12 carbon atoms, X is a hydrocarbon group having 4 to 20 carbon atoms containing an ester group, an ether group, or a carbonyl group, and n is 0 to 5.)

The acrylic-based additive may have a structure represented by Chemical Formula 6 below.

(Wherein R1 and R2 are each a hydrogen atom or a hydrocarbon group having a carbon number of 1 or more, X is an ester group, an ether group, a carbonyl group, or a functional group-containing hydrocarbon group, and n is 1 or more.)

The glass transition temperature (Tg) of the acrylic film may be 94 ° C. or higher, and the amount of the residual solvent may be 150 to 2400 ppm (parts per million).

Since the acrylic film of the present invention is manufactured in a state where the amount of residual solvent is easily controlled, it can be prevented from occurring due to too little or too much residual solvent during peeling during film formation, thereby providing acrylic acid with good quality membrane.

Hereinafter, embodiments of the present invention will be described in detail. However, what is provided here The description is for better understanding of the present invention, and the scope of the present invention is not limited thereto.

The acrylic film according to the embodiment of the present invention may include an acrylic resin including 70 to 96 parts by weight of methyl methacrylate units, and 4 to 30 parts by weight of (meth) acrylic acid other than methyl (meth) acrylate An alkyl ester unit, and an additive selected from the group consisting of an aromatic ester-based additive, a phenol-based additive, and an acrylic-based additive. The acrylic film is produced by a solvent casting method. Moreover, the additive amount is 1 to 10% by weight, which is calculated based on 100% by weight of the main doping solution containing the acrylic resin, the additive, and the solvent.

First, the acrylic resin of the present invention will be described. The acrylic resin of the present invention is a copolymer resin containing methyl methacrylate units and (meth) acrylic acid alkyl ester units other than methyl methacrylate, and each monomer unit contained therein is a repeating unit form.

In consideration of optical characteristics, transparency, compatibility, processability, and productivity, it is preferable that 100 parts by weight of the acrylic resin is composed of 70 to 96 parts by weight of methyl methacrylate units, and 4 to 30 parts by weight of Composed of alkyl (meth) acrylate units other than methyl methacrylate. The content of alkyl (meth) acrylate units other than methyl methacrylate is more preferably 5 to 20 parts by weight.

This is because when the content of the methyl methacrylate unit is within the above range, excellent phase difference and optical characteristics can be obtained. If the methyl methacrylate unit content is less than 70 parts by weight, the optical properties of the acrylic film may be deteriorated. If the amount of the methyl methacrylate unit exceeds 96 parts by weight, the uniformity of the thickness of the acrylic film may be deteriorated.

In addition, the content of the alkyl (meth) acrylate units other than methyl methacrylate within the above range can also provide excellent retardation and optical properties. If the content of the alkyl (meth) acrylate units other than methyl methacrylate is less than 4 parts by weight, the optical performance of the protective film may be deteriorated. If the amount of the (meth) acrylic acid alkyl ester unit exceeds 30 parts by weight, the processability of the film may be deteriorated.

The alkyl (meth) acrylate may be one or two copolymerizable monomers selected from the group consisting of methyl acrylate, butyl acrylate, butyl methacrylate, and methacrylic acid.

The acrylic film of the present invention includes an acrylic resin and an additive selected from the group consisting of an aromatic ester-based additive, a phenol-based additive, and an acrylic-based additive. Through the addition of the additive, the amount of the residual solvent can be easily controlled, and deterioration of the quality of the film due to the residual solvent can be prevented. During the solvent casting process, the main doping solution in which the acrylic resin is dissolved in the solvent is applied to the metal support to form a semi-dry film, and then the film due to the residual solvent may occur when it is peeled off Degradation of quality. And when the protective film is completed, the optical and physical properties of the protective film become insufficient. That is, the amount of residual solvent will have a significant effect on the quality of the acrylic film, so its control is essential. For example, when the amount of the residual solvent is too small, it is difficult to peel the film from the support, and damage to the film may occur. If the amount of residual solvent is too large, the film is too soft and lacks self-supporting property, so that the film can be stretched through the peeling tension. In addition, during the film formation process, during the stretching and / or drying operation, when the amount of the residual solvent is large, the film may shrink excessively, which may adversely affect the physical properties of the film. In addition, if the amount of the organic solvent remaining in the film after production is large, it becomes a problem from the viewpoint of the harmfulness of the product. However, since the solvent mainly used in the solvent casting method is a volatile organic solvent, it is difficult to control the amount of residual solvent in the film. In the present invention, the amount of residual solvent can be easily controlled via the addition of additives.

The content of the additive may be 1 to 10% by weight, preferably 3 to 10% by weight, and more preferably 5 to 10% by weight. When the content of the additive is within the same range as described above, as described above, the amount of the residual solvent can be easily controlled. However, if the content of the additive is too high, the glass transition temperature of the acrylic film may be reduced to an undesired level. Acrylic resin has a smaller intermolecular free volume than triacetylcellulose materials, so when it is made into a film, it remains in the film The diffusion of the solvent becomes relatively slow. As a result, during the film formation, the difference between the drying speed of the solvent on the film surface and the drying speed of the solvent in the film may increase, and surface solidification may occur, thereby allowing a larger amount of solvent to remain in the film. In the present invention, by adding the aforementioned additives to the acrylic resin, the interval between the molecular chains of the acrylic resin becomes wider, and the diffusion of the residual solvent in the resin can be promoted. As a result, since the solvent present therein diffuses toward the surface of the film, and curing of the film surface is delayed. Therefore, the drying of the residual solvent can be performed more efficiently during the film formation process, and the amount of the residual solvent can be controlled more easily.

The aromatic ester-based additive may have, but is not limited to, a structure represented by the following Chemical Formula 1, 2, 3, or 4.

(In Chemical Formula 1, X1 and X2 are hydrocarbon groups of 1 to -20 carbon atoms containing an ester group, an ether group, or a carbonyl group, and n is 1 or more, and m, n, and l in Chemical Formula 2 are each 1 or greater, M and n in Chemical Formula 3 are each 1 or greater, and m in Chemical Formula 4 is 1 or greater.)

The phenol-based additive may have a structure represented by the following Chemical Formula 5.

(Wherein R1-R5 are each independently a hydrogen atom, a halogen atom, a hydrocarbon group or a hydroxyl group having 1 to 12 carbon atoms, X is a hydrocarbon group of 4 to 20 carbon atoms containing an ester group, an ether group, or a carbonyl group, and n is 0 to 5.)

Specific examples of the phenol-based additive include, but are not limited to, additives having the following chemical formulae 5-1 to 5-3.

(In Chemical Formula 5-1, R 1 is a hydrogen atom, a halogen atom, a hydrocarbon group, or a hydroxyl group having 1 to 12 carbon atoms. In Chemical Formula 5-2, R 1 is a hydrogen atom, a halogen atom, a hydrocarbon group, or having 1 to A hydroxyl group of 12 carbon atoms, and i-C8H17 represents isooctyl.)

The acrylic-based additive may have a structure represented by Chemical Formula 6 below.

(Wherein R1 and R2 are each a hydrogen atom or a hydrocarbon group having a carbon number of 1 or more, X is an ester group, an ether group, a carbonyl group, or a functional group-containing hydrocarbon group, and n is 1 or more.)

Specific examples of the acrylic-based additive may include, but are not limited to, additives having a structure of the following Chemical Formula 6-1, and other acrylic-based compounds may also be used.

[Chemical Formula 6-1] The acrylic resin used in the present invention preferably has a molecular weight of 300,000 to 2,500,000 g / mole. If the molecular weight is less than 300,000 g / mole, the production efficiency of the film may decrease. If the molecular weight exceeds 2,500,000 g / mole, the molding process may not be easy.

The glass transition temperature (Tg) of the acrylic film according to the embodiment of the present invention is preferably 94 ° C or higher. When the glass transition temperature is lower than 94 ° C, the heated film may sag, and thus the film may be difficult to handle.

In addition, the amount of the residual solvent of the acrylic film of the present invention may be 150 to 2400 ppm, preferably 150 to 850 ppm, and more preferably 150 to 600 ppm. The amount of the residual solvent refers to the amount of the residual solvent in the finally formed film. Because the acrylic film of the present invention is peeled in the range most suitable for peeling, in order to remove the semi-dry film from the support during the film formation process, it is possible to prevent the film from being caused by too small or excessive residual solvent. Degradation of quality. In addition, since the finally produced acrylic film is peeled off in a state containing a residual solvent of 150 to 2400 ppm, it is possible to prevent deterioration of the quality of the film due to an excessively small or excessive amount of the residual solvent. In addition, as described above, since the acrylic film of the present invention contains a low amount of residual solvent, no dangerous problem occurs when the film is used.

The film thickness of the acrylic film of the present invention is preferably 10 to 60 micrometers (μm). When the thickness of the protective film is less than 10 μm, a sufficient phase difference property as an optical film cannot be exhibited. When the thickness of the protective film exceeds 60 micrometers, it is not suitable as a thin polarizing plate.

Hereinafter, preferred manufacturing methods of the present invention will be described in detail.

Preparation of acrylic resin

In order to manufacture the acrylic film of the present invention, first, a copolymer resin (acrylic resin) solution of a (meth) acrylic acid alkyl ester monomer other than methyl methacrylate monomer and methyl methacrylate is required. The alkyl (meth) acrylate may be one or two copolymerizable monomers selected from the group consisting of methyl acrylate, butyl acrylate, butyl methacrylate, and methacrylic acid.

The method for preparing a copolymer of these monomers is not particularly limited, and the copolymer can be prepared according to a method for preparing a copolymer resin well known in the art, such as suspension polymerization, emulsion polymerization, bulk polymerization, or solution polymerization.

Preparation of main doping solution including acrylic resin and additives

According to the present invention, the film system is prepared via a solvent casting method (a solution film forming method). In the solvent casting method, a main coating liquid solution obtained by dissolving an acrylic resin in a solvent (a casting solvent) is cast on a support, and the solvent is evaporated to form a film. The above-mentioned prepared acrylic resin and additives are mixed in a solvent to prepare a main doping solution.

In the case of preparing a film by a solvent casting method, in order to prepare a main doping solution, an organic solvent is preferred for the solvent. As the organic solvent, a halogenated hydrocarbon is preferably used. As the halogenated hydrocarbon, there are chlorinated hydrocarbon, dichloromethane, and chloroform, and among them, dichloromethane is most preferably used.

Moreover, you may mix and use other organic solvents other than a halogenated hydrocarbon. Organic solvents include esters, ketones, ethers, alcohols, and hydrocarbons. As the ester, methyl formate, ethyl formate, propyl formate, pentyl formate, methyl methacrylate, ethyl ethacrylate, pentyl acrylate, and the like can be used. As the ketone, acetone, methyl ethyl ketone, diethyl ketone, diisobutyl ketone, cyclohexanone, methyl cyclohexanone, and the like can be used. As the ether, diisopropyl ether, dimethoxymethane, dimethoxyethane, 1,4-dioxane, 1,3-dioxolane, tetrahydrofuran, anisole, phenyl ether, and the like can be used. For the alcohol, methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, t-butanol, 1-pentanol, 2-pentanol, 2-methyl-2- Butanol, cyclohexanol, 2-fuller ethanol, 2,2,2-trifluoroethanol, 2,2,3,3- Tetrafluoro-1-propanol and so on.

More preferred systems use dichloromethane as the primary solvent, and alcohols can be used as the secondary solvent. Specifically, the mixed solvent is preferably a mixture of dichloromethane and alcohol in a mixing ratio of 80:20 to 95: 5 by weight.

In the present invention, an additive selected from the group consisting of an aromatic ester-based additive, a phenol-based additive, and an acryl-based additive is used as the additive, and the content of the additive is 1 to 10% by weight.

In the preparation of the acrylic film, in addition to the above-mentioned additives, auxiliary additives may be used. In addition to the above-mentioned additives, various auxiliary additives such as ultraviolet preventive agents, such as particles of core-shell rubber (CSR) particles or silica particles, infrared absorbers, and exfoliants can be added. One or more selected from the group consisting of styrene butadiene rubber, polybutadiene (PBD), and acrylate is used to form a core as a CSR particle, and is selected from methyl methacrylate (MMA One or more of the group consisting of), styrene, and acrylate is used to form a core-shell structure, which is used to form a graft copolymer, but the present invention is not limited thereto. The specific types of these additives can be used without limitation, as long as they are generally used in the art, and their content is preferably in a range that does not impair the physical properties of the film. Addition time of additives and auxiliary additives depends on the type of each additive. Additives can be added at the end of the preparation of the main doping solution.

As described above, the main doping solution can be obtained by a normal temperature, high temperature, or low temperature dissolution method.

Film formation process

In the solvent casting method of the present invention, a main doping solution is cast onto a metal support from a nozzle of a pressure die and left for a predetermined time to form a film in a semi-dry state. The film was then peeled from the metal support and transported to a drying system and the solvent was removed by drying. and, The film in the dried state is subjected to a first-axis stretching process or a second-axis stretching process. Through the execution of the stretching step, the film uniformity and retardation value of the protective film can be improved.

Specifically, the obtained main doping solution was cast on a support via a casting mold to form an acrylic sheet. This support is used to evaporate the solvent present in the casting solution to form an acrylic film, while transferring the sheet casting solution extruded from the die. The support or the surface is made of metal, so it is better to brighten the surface, and for the support, it is better to use a steel belt such as a stainless steel belt. In addition, as for the surface temperature of the metal support, if the temperature is high, the solvent existing in the undiluted solution for casting will evaporate faster, but if the temperature is too high, there will be foaming or deterioration such as the undiluted solution in the casting The problem of flatness, and even if the temperature varies depending on the solvent, the preferred temperature is from 0 to 75 ° C, and more preferably from 5 to 45 ° C. For the support, a metal support in the form of a flat belt may be used.

In addition, the acrylic sheet formed in the above method is subjected to a stretching step of a cloth rack. Under the above conditions, the acrylic film of the present invention is subjected to the stretching step of the cloth frame, and the left and right ends of the film are removed. Therefore, the surface of the film has been damaged by the clips or the pins of the cloth frame and dried. Steps to make a film.

In the case of using the stretching device of the cloth holder, it is preferable to use a device capable of controlling the clamping length of the film from the left and right sides by the left and right holding devices of the cloth holder. In the case of a stretching device using a cloth rack, the stretching operation can be performed in multiple steps, and it is preferable to perform biaxial stretching in the casting direction and the width direction. In addition, biaxial stretching can be performed simultaneously or stepwise. In the "stepwise" case, stretching can be performed continuously in different directions, or stretching in one direction can be divided into multiple steps, and stretching in different directions can be applied to any step. Simultaneous biaxial stretching involves stretching in one direction and relaxation in tension in the other direction to shrink. When performing simultaneous biaxial stretching, the stretching ratio in the width direction and the longitudinal direction is preferably 1.01 to 2.0 times.

The drying device usually blows hot air to both surfaces of the mesh belt, but the heating device can also be obtained by applying a micro-mesh instead of wind. However, too fast drying can easily damage the flatness of the finished film.

Because the acrylic film of the present invention prepared by the above method is prepared by controlling the amount of residual solvent, the sliding performance during film formation is excellent, and the appearance does not appear stained after preparation.

Hereinafter, the present invention will be described in more detail based on examples. However, the present invention is not limited by the following examples.

[Example 1] <Step 1-Preparation of acrylic resin>

An acrylic resin having a butyl methacrylate unit having a structure represented by the following Chemical Formula 7, the content of which is 5 parts by weight, the molecular weight is 650,000 g / mole, and the glass transition temperature (Tg) is 115 ° C. 100 parts by weight of the entire acrylic resin was used.

(Where a and b are each an integer of 1 or more)

<Step 2-Preparation of Main Doping Solution>

29% by weight of an acrylic resin, 1% by weight of an aromatic ester-based additive having a structure represented by the following Chemical Formula 2 and a weight average molecular weight of 1,000 g / mole, and 70% by weight of 9: 1 (weight ratio) Mixed solvent of dichloromethane and methanol in an inline mixer Submix to prepare the main doping solution.

(Where m, n and l are each an integer of 1 or more)

<Step 3-film formation process>

A belt-type flexible device was used to uniformly cast the main doping solution onto a stainless steel belt support having a width of 2000 millimeters (mm). After the solvent was evaporated on the stainless steel belt support, the acrylic resin net was peeled from the stainless steel belt support. Then, the two sides of the net were clamped with a cloth rack, and the net was stretched at a draw ratio of 1.5 times in the TD direction at 130 ° C. After stretching, keep the width for a few seconds. After the tension is relaxed in the width direction, the acrylic resin net will relax in the width direction. And drying the web in a drying section at 90 ° C for 35 minutes, the acrylic film has a thickness of 40 micrometers (μm), and has a width of 1900 millimeters (mm), an end width of 10 millimeters (mm), and 8 Micron (μm) height ridges.

[Example 2]

The procedure of this example is the same as that of Example 1 except that 27% by weight of the acrylic resin and 3% by weight of the aromatic ester-based additive having a structure represented by Chemical Formula 2 are added to the preparation of the main doping solution.

[Example 3]

The procedure of this example is the same as that of Example 1 except that 25% by weight of the acrylic resin and 5% by weight of the aromatic ester-based additive having a structure represented by Chemical Formula 2 are added to the preparation of the main doping solution.

[Example 4]

The procedure of this example is the same as that of Example 1 except that 20% by weight of the acrylic resin and 10% by weight of the aromatic ester-based additive having a structure represented by Chemical Formula 2 are added in the preparation of the main doping solution.

[Example 5]

The implementation procedure of this example is the same as Example 1, except that 29% by weight of the acrylic resin and 1% by weight of the phenol-based additive, the additive has a structure represented by the following Chemical Formula 5-1 and wherein R1 is hydrogen H, which is prepared in The main doping solution is added.

[Example 6]

The procedure of this example is the same as that of Example 1 except that 27% by weight of the acrylic resin and 3% by weight of a phenol-based additive having a structure represented by Chemical Formula 5-1 are added to the preparation of the main doping solution.

[Example 7]

The procedure of this example is the same as that of Example 1 except that 25% by weight of the acrylic resin and 5% by weight of a phenol-based additive having a structure represented by Chemical Formula 5-1 are added to the preparation of the main doping solution.

[Example 8]

Except adding 20% by weight of acrylic resin and 10% by weight of phenol-based additive having a structure represented by Chemical Formula 5-1 in the preparation of the main doping solution, the implementation procedure of this example This is the same as Example 1.

[Example 9]

The implementation procedure of this example is the same as that of Example 1, except that 29% by weight of the acrylic resin and 1% by weight of the phenol-based additive, the additive has a structure represented by the following Chemical Formula 6-1 and its weight average molecular weight is 1000 g / mo Then, it is added when preparing the main doping solution.

[Example 10]

The procedure of this example is the same as that of Example 1 except that 27% by weight of the acrylic resin and 3% by weight of the acrylic-based additive having a structure represented by Chemical Formula 6-1 are added to the preparation of the main doping solution.

[Example 11]

The procedure of this example is the same as that of Example 1 except that 25% by weight of the acrylic resin and 3% by weight of the acrylic-based additive having the structure represented by Chemical Formula 6-1 are added to the preparation of the main doping solution.

[Example 12]

Except adding 20% by weight of an acrylic resin and 10% by weight of an acryl additive having a structure represented by Chemical Formula 6-1 in the preparation of the main doping solution, the implementation of this example The procedure is the same as in Example 1.

[Comparative Example 1]

The procedure of Example 1 was repeated except that 30% by weight of the acrylic resin prepared above was not added when preparing the main doping solution.

[Comparative Example 2]

The procedure of this example is the same as that of Example 1 except that 15% by weight of the acrylic resin and 115% by weight of the aromatic ester-based additive having a structure represented by Chemical Formula 2 are added to the preparation of the main doping solution.

[Comparative Example 3]

The procedure of this example is the same as that of Example 1 except that 15% by weight of acrylic resin and 15% by weight of phenol-based additives having the structure shown in Chemical Formula 5-1 are added to the preparation of the main doping solution.

[Comparative Example 4]

The procedure of this example is the same as that of Example 1 except that 15% by weight of the acrylic resin and 15% by weight of the acrylic-based additive having a structure represented by Chemical Formula 6-1 are added to the preparation of the main doping solution.

Measurement of properties

Each of the acrylic films prepared in Examples 1 to 12 and Comparative Examples 1 to 4 was cut into sheets having a predetermined size according to each measurement method, and its properties were measured in the following manner, and then the results are shown in the following table 1 in.

1. Evaluation of Residual Solvent Amount The amount of the solvent element discharged by each slowly heated acrylic film sample was measured by gas chromatography.

2. Measurement of glass transition temperature using DSC (Differential Scanning Calorimeter) at a temperature rise rate of 10 ° C / min in a temperature range of 40 to 200 ° C Within measurement.

Referring to Table 1 above, without the film prepared by the additive of Comparative Example 1, the amount of the residual solvent in Comparative Example 1 was too much, and when the amount of the additive in Comparative Examples 2 to 4 exceeded When it exceeds 10% by weight, the amount of the residual solvent will not be too large, but because the glass transition temperature is low, it is not suitable for preparing a film. On the other hand, since the acrylic films of Examples 1 to 12 have a low residual solvent amount and a glass transition temperature suitable for preparing a film, the acrylic film according to the embodiment of the present invention can exhibit excellent quality.

Claims (5)

An acrylic film comprising: an acrylic resin consisting of 70 to 96 parts by weight of methyl methacrylate units and 4 to 30 parts by weight of alkyl (meth) acrylate units other than methyl methacrylate ; And an additive selected from the group consisting of an aromatic ester-based additive, a phenol-based additive, and an acrylic-based additive, wherein the acrylic film is prepared by a solvent casting method, and wherein the acrylic acid is contained at 100% by weight The amount of the additive is 1 to 10% by weight based on the main doping solution of the resin, the additive, and the solvent. The acrylic film according to item 1 of the scope of patent application, wherein the aromatic ester-based additive has a structure represented by the following chemical formula 1, 2, 3, or 4: Wherein X1 and X2 in Chemical Formula 1 are hydrocarbon groups having 1 to 20 carbon atoms containing an ester group, ether group, or carbonyl group, and n is 1 or more, and m, n, and l in Chemical Formula 2 are each 1 or more, M and n in Chemical Formula 3 are each 1 or more, and m in Chemical Formula 4 is 1 or more. The acrylic film as described in claim 1, wherein the phenol-based additive has a structure represented by the following Chemical Formula 5. Wherein R1 to R5 are each independently a hydrogen atom, a halogen atom, a hydroxyl group, or a hydrocarbon group having 1 to 12 carbon atoms, X is a hydrocarbon group having an ester group, ether group, or carbonyl group having 4 to 20 carbon atoms, and n is 0 to 5. The acrylic film as described in claim 1, wherein the acrylic-based additive has a structure represented by the following Chemical Formula 6. Wherein R1 and R2 are each a hydrogen atom or a hydrocarbon group having a carbon number of 1 or more, X is an ester group, an ether group, a carbonyl group, or a functional group-containing hydrocarbon group, and n is 1 or more. The acrylic film according to item 1 of the scope of patent application, wherein the glass transition temperature (Tg) of the acrylic film is 94 ° C or higher, and the amount of residual solvent is 150 to 2400 ppm.