JP2011099085A - Antistatic material, antistatic optical film, and manufacturing method of the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an antistatic material which can provide a sufficient antistatic performance, hardly decreases in the antistatic performance over time, and can suppress tackiness of the surface antistatically treated; and to provide an antistatic optical film using the same, and a method for manufacturing the antistatic optical film. <P>SOLUTION: The antistatic material B comprises an ionic conductive material, and a polyester-(meth)acrylic dispersion body. The antistatic optical film is prepared by antistatically treating an optical film with the antistatic material B. The method for manufacturing an antistatic optical film comprises a step of molding a resin into a film shape by a melt extrusion method, and a step of spraying an antistatic material B on the surface of the resin A molded into a film shape to obtain an antistatic optical film antistatically treated with the antistatic material B. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an antistatic material for preventing charging of an antistatic target member such as an optical film, an antistatic optical film using the antistatic material, and a method for producing the antistatic optical film.

  Liquid crystal display devices are widely used in mobile phones, notebook personal computers, personal computer monitors, and the like. In recent years, liquid crystal display devices are often used for television applications, and the demand is rapidly increasing. In the liquid crystal display device, an optical film such as a polarizing film or a retardation film is laminated on one side or both sides of a liquid crystal cell for the purpose of compensating the optical characteristics of the liquid crystal, improving the viewing angle, improving the contrast, or preventing coloring. ing.

  In order to prevent the optical film from being charged, an antistatic material is used.

  Conventionally, an antistatic material has been used for the purpose of preventing charging of various materials such as a thermoplastic resin, a photocurable resin, rubber, or an adhesive.

  As an example of the antistatic material, Patent Document 1 below discloses an antistatic material containing an onium salt of an ionic derivative, which is an ionic liquid, and a polyether polyol.

JP 2007-70421 A

  When an antistatic material such as an optical film is subjected to antistatic treatment with an antistatic material as described in Patent Document 1, antistatic performance may not be sufficiently obtained. Furthermore, the antistatic performance may deteriorate with time. Furthermore, the surface of the antistatic target member that has undergone antistatic treatment may become sticky.

  Further, when the antistatic target member is an optical film, when a liquid crystal display device or the like is formed using the antistatic treated optical film, Newton rings due to light interference may be seen.

  An object of the present invention is to provide a sufficient antistatic performance when used for an antistatic treatment of a member to be prevented from antistatic, and the antistatic performance is unlikely to decrease over time. It is to provide an antistatic material capable of suppressing stickiness on the surface, an antistatic optical film using the antistatic material, and a method for producing the antistatic optical film.

  A limited object of the present invention is to use an antistatic material capable of suppressing the occurrence of Newton's ring resulting from the obtained antistatic optical film, and the antistatic material when used in an antistatic treatment of an optical film. An antistatic optical film and a method for producing the antistatic optical film.

  According to a wide aspect of the present invention, there is provided an antistatic material containing an ionic conductivity imparting agent and a polyester- (meth) acrylic dispersion.

  In a specific aspect of the antistatic material according to the present invention, the ionic conductivity imparting agent preferably includes an anion salt containing a fluorine atom.

  The antistatic material according to the present invention is preferably an antistatic material for optical films.

  In the antistatic optical film according to the present invention, the optical film is antistatically treated with an antistatic material constructed according to the present invention.

  On the specific situation with the antistatic optical film which concerns on this invention, the material of the said optical film is polycarbonate resin.

  The method for producing an antistatic optical film according to the present invention includes a step of forming a resin into a film by a melt extrusion method, and spraying the antistatic material onto the surface of the resin formed into a film, thereby producing an optical film. A step of obtaining an antistatic optical film antistatically treated with the antistatic material, and the antistatic material constructed according to the present invention is used as the antistatic material.

  Since the antistatic material according to the present invention contains an ionic conductivity imparting agent and a polyester- (meth) acrylic dispersion, sufficient antistatic performance when used for antistatic treatment of an antistatic target member. Can be obtained. Furthermore, the antistatic performance is unlikely to decrease with time. Furthermore, stickiness of the surface of the antistatic target member that has undergone antistatic treatment can be suppressed.

  Since the antistatic optical film according to the present invention is antistatically treated with the antistatic material, it is possible to suppress the occurrence of Newton rings due to the obtained antistatic optical film.

FIG. 1 is a schematic configuration diagram showing an example of an apparatus used for forming a resin into a film by a melt extrusion molding method.

  Details of the present invention will be described below.

(Antistatic material)
The antistatic material according to the present invention contains an ionic conductivity imparting agent and a polyester- (meth) acrylic dispersion. The (meth) acryl indicates acryl and methacryl.

  The combined use of the ion conductivity imparting agent and the polyester- (meth) acrylic dispersion can increase the resistance value of the surface of the antistatic target member that has been antistatically treated with the antistatic material. Furthermore, the stickiness of the surface can be suppressed. In addition, the surface treatment film formed by surface treatment using an antistatic material can be made uniform.

  The ion conductivity imparting agent includes, for example, hexafluorophosphate, tetrafluoroborate, trifluoromethanesulfonate, and the like. From the viewpoint of further improving the antistatic performance, the ionic conductivity imparting agent preferably contains an anion salt containing a fluorine atom. Furthermore, from the viewpoint of further improving the antistatic performance, the ionic conductivity imparting agent preferably contains a lithium salt.

  An ionic liquid may be used as the ionic conductivity imparting agent. Specific examples of the ionic liquid include imidazolium salt compounds, quaternary ammonium salt compounds, lithium ionic liquids, and the like. From the viewpoint of further improving the antistatic performance, the ionic conductivity imparting agent is preferably a mixture of a lithium salt compound and a polyol, and the ionic liquid is a mixture of a lithium salt compound and a polyol. Preferably there is.

  Examples of the polyol include polyoxyethylene glycol, polyoxypropylene glycol, polytetramethylene ether glycol, polyoxyethylene glycol-polyoxypropylene glycol block copolymer, and poly having a polyethylene main chain and a polyoxyalkylene glycol side chain. Examples include ether polyols.

  The polyester- (meth) acrylic dispersion has a polyester skeleton and a (meth) acrylic skeleton. Specific examples of the polyester- (meth) acrylic dispersion include an anionic aqueous dispersion, a modifier such as toughness, and a crystalline compound. From the viewpoint of further improving dispersibility, the polyester- (meth) acrylic dispersion is preferably an anionic aqueous dispersion.

  In 100% by weight of the ion conductivity-imparting agent, the content of an anion salt containing a fluorine atom is preferably 1 to 90% by weight. In 100% by weight of the ionic conductivity imparting agent, the more preferable lower limit of the content of the anion salt containing a fluorine atom is 3% by weight, and the more preferable upper limit is 50% by weight. Furthermore, it is preferable that content of lithium salt is 1 to 90 weight% in 100 weight% of said ion conductivity-imparting agents. In 100% by weight of the ion conductivity-imparting agent, a more preferable lower limit of the lithium salt content is 3% by weight, and a more preferable upper limit is 50% by weight.

  The preferable lower limit of the content of the polyester- (meth) acrylic dispersion is 50 parts by weight, the more preferable lower limit is 70 parts by weight, and the preferable upper limit is 150 parts by weight with respect to 100 parts by weight of the ion conductivity-imparting agent. The upper limit is 120 parts by weight. When the content of the polyester- (meth) acrylic dispersion satisfies the preferable lower limit and upper limit, the antistatic performance can be further improved, and the surface of the antistatic target member that has been subjected to the antistatic treatment can be further improved. Can be suppressed.

  The antistatic material may contain a solvent. Examples of the solvent include alcohol solvents such as methanol, ethanol, n-propanol and isopropanol, ether solvents such as tetrahydrofuran, 1,4-dioxane, 1,3-dioxane and diethyl ether, and carbonization such as benzene, toluene and n-hexane. Examples include hydrogen solvents, ketone solvents such as acetone, methyl ethyl ketone and cyclohexanone, ester solvents such as ethyl acetate and butyl acetate, and water. As for the said solvent, only 1 type may be used and 2 or more types may be used together. From the viewpoint of reducing the adverse effect of the solvent, the solvent is preferably water. Furthermore, from the viewpoint of easily volatilizing the solvent, the solvent is preferably a low boiling point solvent. As the low boiling point solvent, an alcohol solvent such as methanol, ethanol, n-propanol or isopropanol is preferably used.

  When the antistatic material contains a solvent, the preferred lower limit of the total content of the ionic conductivity imparting agent and the polyester- (meth) acrylic dispersion in 100 wt% of the antistatic material is 0.1 wt%, A more preferred lower limit is 0.5% by weight, a preferred upper limit is 5% by weight, and a more preferred upper limit is 3% by weight.

  The average diameter of the polyester- (meth) acrylic dispersion in the antistatic material is preferably in the range of 0.5 to 3 μm. When the average diameter is within the above range, stickiness of the surface of the antistatic target member subjected to antistatic treatment can be further suppressed.

  The method for producing the antistatic material is not particularly limited. For example, the antistatic material can be obtained by adding and mixing the polyester- (meth) acrylic dispersion and other components blended as necessary to the ion conductivity-imparting agent.

  The antistatic material can be used for preventing charging of various antistatic target members. Although it does not specifically limit as said antistatic target member, An optical film etc. are mentioned. Furthermore, the antistatic material can be used to prevent charging of various materials such as thermoplastic resin, curable resin, rubber, pressure-sensitive adhesive, or adhesive.

(Surface-treated optical film)
The antistatic target member to be antistatic treated with the antistatic material is preferably an optical film.

  The antistatic optical film according to the present invention is obtained by subjecting an optical film to an antistatic treatment with the antistatic material. The antistatic optical film is preferably an optical film whose surface is treated with the antistatic material. The antistatic optical film preferably includes an optical film and a surface treatment film formed of the antistatic material on the surface of the optical film. The surface treatment film is preferably a thin film. However, the antistatic material can be used not only for the surface treatment of the optical film but also mixed with the optical film material.

  The thickness of the surface treatment film is not particularly limited. The thickness of the surface treatment film is about 0.5 to 3 μm.

  When a liquid crystal display device or the like is formed using the antistatic optical film, it is preferable that no Newton ring due to light interference is observed. When an antistatic optical film antistatically treated with a conventional antistatic material is used, the generation of Newton rings may not be sufficiently suppressed. By using an antistatic material containing an ionic conductivity imparting agent and a polyester- (meth) acrylic dispersion, the generation of Newton rings can be effectively suppressed.

  The material of the optical film is preferably a resin, and more preferably a thermoplastic resin. Specific examples of the material of the optical film include, for example, thermoplastic saturated norbornene resin, polycarbonate resin, polysulfone resin, polyether sulfone resin, poly (meth) acrylate resin, polyarylate resin, polystyrene resin, polyacetal resin, Examples thereof include polyvinyl chloride resin, cellulose resin, acrylonitrile resin, polyolefin resin, and olefin-maleimide copolymer. Only 1 type may be used for the material of the said optical film, and 2 or more types may be used together.

  From the viewpoint of further improving optical properties (increasing brightness), the material of the optical film is preferably a polycarbonate resin.

From the viewpoint of further improving the antistatic performance, the resistance value of the antistatic surface of the antistatic optical film is preferably in the range of 10 ⁸ to 10 ¹¹ Ωcm.

  The thickness of the antistatic optical film is not particularly limited. The thickness of the antistatic optical film is, for example, about 20 to 500 μm.

  Although it does not specifically limit as said antistatic optical film, A phase difference film, a polarizer protective film, a brightness improvement sheet, etc. are mentioned. Moreover, a polarizing plate provided with an antistatic optical film and a polarizer can be obtained by laminating the retardation film or the polarizer protective film on at least one surface of the polarizer.

(Method for producing antistatic optical film)
Examples of the method for producing the antistatic optical film include a solution casting method and a melt molding method. Examples of the melt molding method include a melt extrusion molding method, a press molding method, and an injection molding method. In particular, the effects of the present invention are effectively exhibited by adopting the melt molding method, particularly by adopting the melt extrusion molding method. Examples of the melt extrusion molding method include a T-die method and an inflation method.

  The method for producing an antistatic optical film according to the present invention comprises a step of forming a resin into a film form by a melt extrusion method, and spraying the antistatic material onto the surface of the resin formed into a film form. Obtaining an antistatic optical film that has been antistatically treated with an antistatic material.

  The antistatic optical film can be produced using, for example, the apparatus shown in FIG.

  FIG. 1 is a schematic configuration diagram illustrating an example of an apparatus used for forming a resin into a film by a melt extrusion molding method.

  As shown in FIG. 1, when the resin is formed into a film, the resin is first extruded from the extruder 1 and supplied to the mold 4. A gear pump 2 is disposed between the extruder 1 and the mold 4. A filter 3 is disposed between the extruder 1 and the mold 4. The filter 3 is disposed between the gear pump 2 and the mold 4. However, the gear pump 2 and the filter 3 are not necessarily used.

  The resin supplied to the mold 4 is extruded from the opening of the mold 4 and discharged, and the resin is formed into a film. The discharged film-like resin A is brought into contact with the cooling roll 12 and cooled. In order to press the resin A against the cooling roll 12, a cooling roll 11 as a touch roll is provided. Instead of the cooling roll 11, an air knife or electrostatic pinning may be used.

  The resin A cooled by the cooling roll 12 is further cooled by the cooling rolls 13 and 14 and wound up.

  In the apparatus shown in FIG. 1, a spraying device 15 for spraying the antistatic material B onto the film-like resin A that has passed through the cooling roll 13 is installed. The antistatic material B contains an ionic conductivity imparting agent and a polyester- (meth) acrylic dispersion. By spraying the antistatic material B onto the film-like resin A from the nozzle 15a of the spraying device 15, the optical film is subjected to antistatic treatment. The surface of the optical film is treated by spraying the antistatic material B. In this way, an antistatic optical film can be obtained.

  By using the apparatus shown in FIG. 1, the antistatic treatment can be performed in-line. The antistatic treatment is preferably performed in-line.

  The installation location of the spray device 15 is not particularly limited. From the viewpoint of further improving the antistatic performance, spraying of the antistatic material B is performed after the resin is formed into a film and before the resin (molten resin) formed into a film is completely solidified. Is preferred.

  From the viewpoint of uniformly antistatic treatment of the optical film, the pressure during spraying of the antistatic material is preferably in the range of 0.1 to 1 MPa. From the viewpoint of further improving the antistatic performance, the temperature of the resin A when the antistatic material is sprayed (sprayed region) is preferably in the range of 55 to 120 ° C. Further, when the temperature of the resin A at the time of spraying is 55 ° C. or more, when the antistatic material contains a solvent, the solvent hardly remains in the obtained antistatic optical film. Therefore, the physical properties of the obtained antistatic optical film are less likely to change over time.

  The present invention will be described in more detail with reference to the following examples. The present invention is not limited to these examples.

Example 1
As an ionic conductivity imparting agent, PEL25 (made by Nippon Carlit Co., Ltd., 5 parts by weight of lithium trifluoromethanesulfonate and 10 parts by weight of lithium perchlorate were mixed with 85 parts by weight of polyoxyethylene glycol-polyoxypropylene glycol copolymer). In addition, 1 part by weight of pesresin MYX-570 (manufactured by Takamatsu Yushi Co., Ltd.) as a polyester- (meth) acrylic dispersion and 100 parts by weight of water are added to 1 part by weight of the prepared ionic conductivity-imparting agent and mixed. Thus, an antistatic material having a solid pesresin average diameter of 1 μm was obtained.

(Example 2)
An antistatic material was obtained in the same manner as in Example 1 except that the addition amount of PEL25 was changed from 1 part by weight to 1.2 parts by weight.

(Example 3)
An antistatic material was obtained in the same manner as in Example 1 except that the addition amount of PEL25 was changed from 1 part by weight to 0.8 part by weight.

Example 4
15 parts by weight of lithium hexafluorophosphate (manufactured by Stella Chemifa) is mixed with 85 parts by weight of a polyethylene-polyoxyethylene glycol graft copolymer (“Sumiade 300G” manufactured by Sumitomo Chemical Co., Ltd.) which is a polyether polyol, An ionic conductivity imparting agent was prepared.

  Next, 1 part by weight of pesresin MYX-570 (manufactured by Takamatsu Yushi Co., Ltd.) as a polyester- (meth) acrylic dispersion and 100 parts by weight of water are added to 1 part by weight of the prepared ion conductivity imparting agent. By mixing, an antistatic material having a solid pesresin average diameter of 1 μm was obtained.

(Example 5)
15 parts by weight of lithium borofluoride (manufactured by Stella Chemifa Co., Ltd.) is mixed with 85 parts by weight of a polyethylene-polyoxyethylene glycol graft copolymer (“Sumiade 300G” manufactured by Sumitomo Chemical Co., Ltd.), which is a polyether polyol, to impart ionic conductivity. An agent was prepared.

  Next, 1 part by weight of pesresin MYX-570 (manufactured by Takamatsu Yushi Co., Ltd.) as a polyester- (meth) acrylic dispersion and 100 parts by weight of water are added to 1 part by weight of the prepared ion conductivity imparting agent. By mixing, an antistatic material having a solid pesresin average diameter of 1 μm was obtained.

(Comparative Example 1)
In the same manner as in Example 1, except that pesresin MYX-570 was changed to a polyethylene-polyoxyethylene glycol graft copolymer ("Sumiade 300G" manufactured by Sumitomo Chemical Co., Ltd.) which is a polyether polyol, an antistatic material was used. Obtained.

(Comparative Example 2)
1 part by weight of PEL-25 and 100 parts by weight of water were mixed to obtain an antistatic material.

(Evaluation)
(1) Production of Evaluation Sample A retardation film was obtained by a melt extrusion method using an apparatus having a schematic configuration shown in FIG. The specification of the apparatus shown in FIG. 1 is as follows.

Extruder 1: Co-directional twin-screw extruder Mold 4: T-die Cooling rolls 12-14: Metallic mirror roll Cooling roll 11: Metallic sleeve roll

  Using the above apparatus, polycarbonate resin (“Panlite K-1300Y” manufactured by Teijin Kasei Co., Ltd.) was supplied from the extruder 1 to the mold 4, and the resin was extruded from the mold 4 into a film shape and molded. The temperature of the resin during melt extrusion was 280 ° C. The temperature of the resin during extrusion was adjusted by controlling the temperature from the tip of the extruder 1 to the mold 4.

  The melt-extruded resin film is sandwiched between a cooling roll 12 of 100 ° C. and a cooling roll 11 of 60 ° C., passed through a cooling roll 13 of 90 ° C. and a cooling roll 14 of 80 ° C., and then cooled. Rolled up to obtain a retardation film having an average thickness of 100 μm. During cooling, the obtained antistatic material was sprayed from the nozzle 15a of the spraying device 15 at a pressure of 0.5 MPa onto the film-like resin A that passed through the cooling roll 13 and before passing through the cooling roll 14. . The temperature of the resin A at the time of spraying the antistatic material (sprayed region) was 80 ° C.

  In this way, a retardation film was obtained as an antistatic optical film that was antistatically treated (surface treated) with the antistatic material. The obtained retardation film was used as an evaluation sample.

(2) Antistatic performance Using SME-8310 (manufactured by Toa DKK), the initial surface specific resistance value of the obtained evaluation sample was measured to evaluate the initial antistatic performance. Next, the evaluation sample was allowed to stand for 1 day at 23 ° C. and a relative humidity of 65% RH. The surface specific resistance value of the evaluation sample after standing was measured to evaluate the antistatic performance after aging.

(3) Anti-sticking effect on surface and slipperiness A finger was brought into contact with the surface of the evaluation sample, and the anti-sticking effect on the surface was evaluated with a sensuality. The case where there was no surface stickiness was evaluated as “◯”, and the case where there was surface stickiness as “X”, and the surface stickiness prevention effect was determined.

  Further, the tribomaster TL102 (manufactured by Trinity Laboratories) was used to measure the coefficient of static friction of the evaluation sample and evaluate the surface slipperiness. When the coefficient of static friction is 0.50 or less, the slipperiness is good. It is important to achieve both surface stickiness and slipperiness.

(4) Newton ring The transparent sample sheet was laminated | stacked on the evaluation sample, and the presence or absence of the Newton ring of the evaluation sample was evaluated by visual observation from the top. As the PET sheet, FE-2000 (thickness: 100 μm) manufactured by Nimura Chemical was used.

  The results are shown in Table 1 below.

DESCRIPTION OF SYMBOLS 1 ... Extruder 2 ... Gear pump 3 ... Filter 4 ... Mold 11-14 ... Cooling roll 15 ... Spraying device 15a ... Nozzle A ... Resin B ... Antistatic material

Claims (6)

  An antistatic material containing an ionic conductivity imparting agent and a polyester- (meth) acrylic dispersion.   The antistatic material according to claim 1, wherein the ion conductivity-imparting agent contains an anion salt containing a fluorine atom.   The antistatic material according to claim 1, which is an antistatic material for an optical film.   An antistatic optical film, wherein the optical film is antistatically treated with the antistatic material according to claim 1.   The antistatic optical film according to claim 4, wherein the material of the optical film is a polycarbonate resin. Forming a resin into a film by a melt extrusion method;
A step of spraying the antistatic material onto the surface of a resin formed into a film to obtain an antistatic optical film that has been antistatically treated with the antistatic material,
The manufacturing method of the antistatic optical film which uses the antistatic material of any one of Claims 1-3 as said antistatic material.

Images