JP2012126767A - Luminance-increasing film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a luminance-increasing film which is made from a polycarbonate resin, the film being excellent in transparency, flowability, heat resistance, transferability, and moisture/heat resistance which hardly causes a change in form such as a distortion or warp in a high temperature and humidity environment.SOLUTION: The luminance-increasing film is a film which is formed from a polycarbonate resin composition, in which 0.17-0.40 pt.wt. of an alcohol-fatty acid ester and 0.001-0.1 pt.wt. of a phosphorous-based stabilizer are mixted together to 100 pts.wt. of a polycarbonate resin whose viscosity-average molecular weight is 1.0×10to 2.5×10, the film is imparted on its surface with an unevenness arranged regularly.

Description

  The present invention relates to a brightness enhancement film comprising a polycarbonate resin composition.

  A liquid crystal display device such as a liquid crystal television or a personal computer is generally composed of a liquid crystal panel, a reflective polarizing film, a brightness enhancement film, a diffusion film, a backlight unit, and a reflector. By incorporating the brightness increasing film on the front surface of the backlight unit, the light emitted from the light source can be condensed toward the display and the brightness on the front surface can be improved.

  Conventionally, the brightness enhancement film is mainly an optical film in which an acrylic resin having a prism shape is laminated on the surface of a polyester resin sheet. However, due to the recent increase in the size of liquid crystal display devices, problems such as warping and waviness due to the difference in shrinkage of each resin that makes up the brightness enhancement film occur. It is being considered. Furthermore, along with the reduction in thickness, thinning of the brightness enhancement film is required, and the inside of the device tends to become high temperature due to heat generated in the vicinity of the light source, and the shape change due to environmental changes such as temperature and humidity is small. There is a demand for a resin material having excellent resistance to moisture and heat. Moreover, since it becomes high temperature shaping | molding in order to obtain a large thin-film brightness enhancement film, the fluidity | liquidity at the time of forming a brightness enhancement film from a resin material and a transferability are also required.

  Patent Document 1 discloses a film made of a thermoplastic resin having a water absorption rate of 0.25% by weight or less. However, it is described that the film is used as a protective layer of a light diffusion plate of a liquid crystal display device. Patent Document 2 discloses an optical sheet having specific physical properties such as a low water absorption having a lens shape or a prism shape on one side. Although it is described that a polycarbonate resin is used as the material of the optical sheet, its composition is not described.

JP-A-2005-225108 JP 2008-096930 A

  The present invention provides a brightness-enhancing film made of a polycarbonate resin that has excellent transparency, fluidity, heat resistance and transferability, and is excellent in moisture and heat resistance, which is unlikely to cause deformation such as bending and warping in a hot and humid environment. For the purpose.

〔式中、Ｒ^１〜^４は炭素数１〜２０の直鎖状もしくは分岐状のアルキル基、または直鎖状もしくは分岐状のアルキル基で置換されてもよい炭素数１〜２０のアリール基を示し、それぞれ同一であっても異なっていてもよい〕
３．規則的に配列された凹凸形状は、ピッチが１０〜３００μｍ、高さが１０〜３００μｍであるレンチキュラー型、プリズム型、およびリニアーフレネル型形状からなる群より選ばれる少なくとも一種である上記１記載の輝度上昇フィルム。
４．厚みが０．１〜１．０ｍｍである上記１記載の輝度上昇フィルム。
５．０．３ｍｍ厚における透湿度が１５〜２０ｇ／ｍ^２／２４ｈ（ＪＩＳ Ｚ ０２０８準拠）である上記１記載の輝度上昇フィルム。 The present invention adopts the following configuration in order to solve the above problems.
1. 0.1100 to 0.40 parts by weight of an ester of an alcohol and a fatty acid with respect to 100 parts by weight of a polycarbonate resin having a viscosity average molecular weight of 1.0 × 10 ^{4 to} 2.5 × 10 ⁴ A brightness enhancement film which is a film formed from a polycarbonate resin composition comprising 001 to 0.1 parts by weight, and which has irregularities regularly arranged on the surface thereof.
2. 2. The brightness enhancement film as described in 1 above, wherein the phosphorus stabilizer is a phosphorus compound represented by the following formula (I).

[Wherein, R ¹ to ⁴ represent a linear or branched alkyl group having 1 to 20 carbon atoms, or an aryl group having 1 to 20 carbon atoms which may be substituted with a linear or branched alkyl group. Each may be the same or different)
3. 2. The luminance according to 1 above, wherein the regularly arranged uneven shape is at least one selected from the group consisting of a lenticular type, a prism type, and a linear Fresnel type shape having a pitch of 10 to 300 μm and a height of 10 to 300 μm. Rising film.
4). 2. The brightness enhancement film as described in 1 above, wherein the thickness is from 0.1 to 1.0 mm.
5.0.3mm brightness enhancement film of claim 1, wherein the a moisture permeability ^{15~20g / m 2 / 24h (JIS} Z 0208 compliant) in thickness.

  According to the present invention, there is provided a brightness enhancement film made of a polycarbonate resin which has excellent transparency, fluidity, heat resistance and transferability, and is excellent in moisture and heat resistance, which is unlikely to cause deformation such as bending and warping in a high temperature and high humidity environment. Can be provided.

It is a figure which shows the measuring method of curvature amount. It is the figure which expanded the shaping surface vicinity. It is the figure which showed the one aspect | mode of the manufacturing apparatus of a brightness enhancement film.

Hereinafter, the present invention will be described in detail.
[Polycarbonate resin]
The polycarbonate resin used in the present invention is obtained by reacting a dihydric phenol and a carbonate precursor. Examples of the reaction method include an interfacial polycondensation method, a melt transesterification method, a solid phase transesterification method of a carbonate prepolymer, and a ring-opening polymerization method of a cyclic carbonate compound. The polycarbonate resin may be produced by any production method, and in the case of interfacial polycondensation, a terminal stopper of a monohydric phenol is usually used. The polycarbonate resin may be a branched polycarbonate obtained by polymerizing a trifunctional or higher polyfunctional component in addition to the dihydric phenol or difunctional alcohol. Further, it may be a branched polycarbonate resin obtained by polymerizing polyfunctional phenols such as trifunctional phenols, and further, an aliphatic dicarboxylic acid or aromatic dicarboxylic acid, a polyorganosiloxane component, and a vinyl monomer may be copolymerized. Copolymer polycarbonate may also be used. Representative examples of dihydric phenols include 2,2-bis (4-hydroxyphenyl) propane (commonly known as bisphenol A), 1,1-bis (4-hydroxyphenyl) ethane, and 1,1-bis (4-hydroxyphenyl). ) Cyclohexane, 2,2-bis (4-hydroxy-3,5-dimethylphenyl) propane, 2,2-bis (4-hydroxy-3,5-dibromophenyl) propane, bis (4-hydroxyphenyl) sulfide, Examples thereof include bis (4-hydroxyphenyl) sulfone. A preferred dihydric phenol is a bis (4-hydroxyphenyl) alkane series, and bisphenol A is particularly preferred.

  In a reaction using, for example, phosgene as a carbonate precursor, the reaction is usually performed in the presence of an acid binder and a solvent. As the acid binder, for example, an alkali metal hydroxide such as sodium hydroxide or potassium hydroxide or an amine compound such as pyridine is used. As the solvent, for example, halogenated hydrocarbons such as methylene chloride and chlorobenzene are used. In order to accelerate the reaction, a catalyst such as a tertiary amine or a quaternary ammonium salt can also be used. In that case, reaction temperature is 0-40 degreeC normally, and reaction time is several minutes-5 hours.

  For example, a transesterification reaction using a carbonic acid diester as a carbonate precursor is carried out by a method in which an aromatic dihydroxy component in a predetermined ratio is stirred with a carbonic acid diester while heating in an inert gas atmosphere to distill the resulting alcohol or phenol. Is called. The reaction temperature varies depending on the boiling point of the alcohol or phenol produced, but is usually in the range of 120 to 300 ° C. The reaction is completed while distilling off the alcohol or phenol produced under reduced pressure from the beginning. Moreover, in order to accelerate | stimulate reaction, the catalyst normally used for transesterification can also be used. Examples of the carbonic acid diester used in the transesterification include diphenyl carbonate, dinaphthyl carbonate, bis (diphenyl) carbonate, dimethyl carbonate, diethyl carbonate, and dibutyl carbonate. Of these, diphenyl carbonate is particularly preferred.

  Monofunctional phenols usually used as a terminal terminator can be used. Particularly in the case of a reaction using phosgene as a carbonate precursor, monofunctional phenols are generally used as a terminator for controlling the molecular weight, and the resulting aromatic polycarbonate resin has a terminal monofunctional phenol. Since it is blocked by a group based on, it is superior in thermal stability as compared to those not. Such monofunctional phenols may be used as long as they are used as an end stopper for aromatic polycarbonate resins. Specific examples of the monofunctional phenols include phenol, p-tert-butylphenol, and p-cumyl. Phenol and isooctylphenol are mentioned.

  In producing the polycarbonate resin, the above dihydric phenols can be used alone or in combination of two or more thereof, and a molecular weight regulator, a branching agent, a catalyst and the like can be used as necessary.

The molecular weight of the polycarbonate resin is 1.0 × 10 ^{4 to} 2.5 × 10 ⁴ in terms of viscosity average molecular weight, preferably 1.3 × 10 ^{4 to} 2.3 × 10 ⁴ , and more preferably 1. 5 × a ^{10 4 ~2.1} × ¹⁰ 4. The viscosity average molecular weight referred to in the present invention is obtained by inserting the specific viscosity (η _sp ) obtained from a solution obtained by dissolving 0.7 g of polycarbonate resin in 100 ml of methylene chloride at 20 ° C. into the following equation.
η _sp /c=[η]+0.45×[η] ² c (where [η] is the intrinsic viscosity)
[Η] = 1.23 × 10 ⁻⁴ M ^0.83
c = 0.7

  The polycarbonate resin suitably used in the present invention preferably has a OH terminal amount in the range of 1 to 5,000 ppm by weight of OH groups, more preferably in the range of 5 to 2,000 ppm, still more preferably. It is in the range of 10 to 10,000 ppm.

[About esters of alcohol and fatty acids]
The ester of alcohol and fatty acid used in the present invention is effective not only in improving moldability such as transferability, releasability and fluidity, but also in suppressing shape change such as deflection and warpage in a high temperature and high humidity environment. Demonstrate.

  Specific examples of the ester of an alcohol and a fatty acid include an ester of a monohydric alcohol and a fatty acid and / or a partial ester or a total ester of a polyhydric alcohol and a fatty acid. The ester of the monohydric alcohol and the fatty acid is preferably an ester of a monohydric alcohol having 1 to 20 carbon atoms and a saturated fatty acid having 10 to 30 carbon atoms. Moreover, as a partial ester or total ester of a polyhydric alcohol and a fatty acid, a partial ester or a total ester of a polyhydric alcohol having 1 to 25 carbon atoms and a saturated fatty acid having 10 to 30 carbon atoms is preferable.

  Examples of the ester of a monohydric alcohol and a saturated fatty acid include stearyl stearate, palmityl palmitate, butyl stearate, methyl laurate, isopropyl palmitate, and stearyl stearate is particularly preferable.

  Examples of partial esters or total esters of polyhydric alcohols and saturated fatty acids include glycerol monostearate, glycerol distearate, glycerol tristearate, glycerol monobehenate, pentaerythritol monostearate, pentaerythritol tetrastearate, pentaerythritol. Examples include all or partial esters of dipentaerythritol, such as tetrapelargonate, propylene glycol monostearate, biphenyl biphenate, sorbitan monostearate, 2-ethylhexyl stearate, and dipentaerythritol hexastearate. . Among these, glycerin monostearate, glycerin tristearate, pentaerythritol tetrastearate, and a mixture of glycerin tristearate and stearyl stearate are preferable. In particular, pentaerythritol tetrastearate and glycerin monostearate are preferable.

  The acid value of the fatty acid ester is preferably 3 or less, and more preferably 2 or less. In the case of glycerol monostearate, an acid value of 1.5 or less and a purity of 95% by weight or more are preferred, and an acid value of 1.2 or less and a purity of 98% by weight or more are particularly preferred. A known method can be used to measure the acid value of the fatty acid ester.

  The compounding quantity of ester of alcohol and a fatty acid is the range of 0.17-0.40 weight part with respect to 100 weight part of polycarbonate resin, The range of 0.20-0.35 weight part is preferable, 0.25-0.25 A range of 0.30 parts by weight is most preferred. When the amount of the ester of alcohol and fatty acid is less than 0.17 parts by weight, the fluidity and heat-and-moisture resistance are inferior. And the transferability is also inferior.

[Phosphorus stabilizer]
In the present invention, a phosphorus stabilizer is used as a stabilizer of the polycarbonate resin composition, and preferably, a phosphorus compound in which various phosphinic acid esters are substituted on each ring of biphenyl represented by the following formula (I) is used. The

〔式中、Ｒ^１〜^４は炭素数１〜２０の直鎖状もしくは分岐状のアルキル基、または直鎖状もしくは分岐状のアルキル基で置換されてもよい炭素数１〜２０のアリール基を示し、それぞれ同一であっても異なっていてもよい〕

[Wherein, R ¹ to ⁴ represent a linear or branched alkyl group having 1 to 20 carbon atoms, or an aryl group having 1 to 20 carbon atoms which may be substituted with a linear or branched alkyl group. Each may be the same or different)

  Specifically, tetrakis (2,4-di-tert-butylphenyl) -4,4′-biphenylenediphosphonite, tetrakis (2,4-di-tert-butylphenyl) -4,3′-biphenylenedi Phosphonite, tetrakis (2,4-di-tert-butylphenyl) -3,3′-biphenylenediphosphonite, tetrakis (2,6-di-tert-butylphenyl) -4,4′-biphenylenediphosphonite Tetrakis (2,6-di-tert-butylphenyl) -4,3′-biphenylenediphosphonite, tetrakis (2,6-di-tert-butylphenyl) -3,3′-biphenylenediphosphonite, tetrakis (2,4-di-tert-butyl-5-methylphenyl) -4,4′-biphenylenediphosphonite, tetrakis ( , 4-Di-tert-butyl-5-methylphenyl) -4,3'-biphenylenediphosphonite, tetrakis (2,4-di-tert-butyl-5-methylphenyl) -3,3'-biphenylenedi There are phosphonites, tetrakis (di-tert-butylphenyl) -biphenylenediphosphonite is preferred, and tetrakis (2,4-di-tert-butylphenyl) -biphenylenediphosphonite is more preferred.

  The amount of the phosphorus stabilizer is 0.001 to 0.1 part by weight, preferably 0.003 to 0.06 part by weight, based on 100 parts by weight of the polycarbonate resin, and 0.01 to 0. A range of 0.05 parts by weight is most preferred. If the amount of the phosphorus compound is less than 0.001 part by weight, the molding heat resistance of the polycarbonate resin is insufficient, which is not preferable. Moreover, when it exceeds 0.1 weight part, it will become easy to produce roll contamination at the time of a physical-property fall and shaping | molding, and is unpreferable.

In addition to the phosphorus stabilizer, other phosphorus stabilizers, hindered phenol stabilizers, and the like may be used in combination.
In the present invention, other resin additives such as ultraviolet absorbers, fluorescent brighteners, flame retardants, antistatic agents, lubricants, plasticizers and the like may be blended within the range not impairing the object of the present invention. Good.

  The polycarbonate resin composition of the present invention may contain other resins as long as the effects of the present invention are not impaired. Other resins include, for example, polyamide resins; polyimide resins; polyetherimide resins; polyurethane resins; polyphenylene ether resins; polyphenylene sulfide resins; polysulfone resins; polyolefin resins such as polyethylene and polypropylene; polystyrene, acrylonitrile-styrene copolymers, etc. Styrenic resin of polymethacrylate resin, phenol resin, epoxy resin, etc. are mentioned. The compounding amount of the other resin is usually 40 parts by weight or less, preferably 30 parts by weight or less, with respect to 100 parts by weight of the aromatic polycarbonate resin.

[About molding method of polycarbonate resin composition]
Arbitrary methods are employ | adopted in order to manufacture the polycarbonate resin composition used by this invention. For example, the polycarbonate resin, the ester of alcohol and fatty acid, the phosphorus stabilizer, and optionally other additives can be sufficiently added using a premixing means such as a V-type blender, a Henschel mixer, a mechanochemical apparatus, an extrusion mixer, etc. Then, if necessary, granulate the premixed mixture with an extrusion granulator or briquetting machine, and then melt and knead it with a melt kneader typified by a vent type twin screw extruder, and then with a pelletizer. The method of pelletizing is mentioned.

  The blending of the polycarbonate resin with the ester of alcohol and fatty acid, the phosphorus stabilizer and other additives may be carried out in one stage, but may be carried out in two or more stages. For example, after blending a part of the polycarbonate resin powder or pellets to be blended with the additive, that is, the additive is diluted with the polycarbonate resin powder. After that, there is a method of performing final blending using this.

  For example, in the method of blending in a single step, a method in which each predetermined amount of each additive is mixed in advance with polycarbonate resin powder or pellets, and each predetermined amount of each additive is separately measured to obtain a polycarbonate resin. For example, a method of sequentially adding powder and pellets and then blending can be employed. In blending additives other than phosphorus compounds, such additives can be directly added and injected into an extruder. In that case, it is also possible to inject each additive after heating and melting.

Fluidity of the polycarbonate resin composition used in the present invention is ^preferably 25 cm 3 / 10min or ^higher, more preferably in the range of 25~40cm 3 / ^10min, more preferably in the range of 30 to 35 cm 3 / 10min. Within the above range, the fluidity is excellent and the transferability of the film is good.

[About brightness enhancement film]
The brightness enhancement film of the present invention preferably has a thickness in the range of 0.1 to 1.0 mm, and is a film formed with irregularities regularly arranged on the surface. The concavo-convex shape has a pitch of preferably 10 to 300 μm, more preferably 20 to 100 μm, and a height of preferably 10 to 300 μm, more preferably 20 to 250 μm, still more preferably 100 to 200 μm. What is at least 1 type chosen from the group which consists of a type | mold and a linear Fresnel type | mold shape is preferable.

  The production method of the brightness enhancement film of the present invention is not particularly limited, and examples thereof include a melt extrusion method and a solution casting method (casting method). A specific method of the melt extrusion method is, for example, that a polycarbonate resin is quantitatively supplied to an extruder, heated and melted, and the molten resin is extruded in a film form on a mirror surface roll from a tip end of a T die, and a plurality of rolls are used. A method is used in which it is taken up while being cooled and cut or wound into an appropriate size when solidified. A specific method of the solution casting method is, for example, casting a solution of polycarbonate resin in methylene chloride (concentration 5% to 40%) from a T-die onto a mirror-polished stainless steel plate, and controlling the temperature stepwise. The film is peeled off while passing through the oven, the solvent is removed, and the film is cooled and wound.

  When melt-extruding, the polycarbonate resin can be melt-extruded with a glass extruder at a glass transition point to a glass transition point + 230 ° C., preferably a glass transition point + 50 ° C. to a glass transition point + 200 ° C. The melt extruder may be a single screw extruder or a twin screw extruder. In order to prevent thermal deterioration of resin, coloring, prevention of T-die lip, and roll contamination, vacuum degassing by vent suction, suction degassing in hopper, and hopper or barrel of inert gas such as nitrogen Infusion can be performed. In the case of vent suction, the pressure is preferably reduced at 1.33 to 66.5 kPa.

  The film extruded in the molten state is cooled while being nipped by the first roll, the second roll, and the third roll. At this time, the film is given a fine uneven shape by the engraving grooves formed on the surface of the second roll, cooled, and then taken up by the take-up roll. The roll diameters of the first to third rolls used here do not need to be particularly restricted and need not be unified to the same roll diameter, but the roll diameter is usually 200 mm or more, and particularly the same diameter of 250 to 500 mm. Are preferably used. Any of the rolls may be subjected to various coating treatments including a resin coat on the roll surface. The pitch of the engraving groove of the engraving groove roll to be used is preferably 10 to 300 μm, more preferably 20 to 100 μm. The pitch of the convex shape in the shaped film depends on the pitch of the engraving grooves of the roll. It is desirable that the convex shapes in the present invention have the same pitch. Therefore, the pitch of the engraving grooves is a constant value, and as a result, a film in which fine irregularities are regularly arranged at the same pitch is desirable. Basically, the pitch value is appropriately determined in the required optical design. However, in the range of 10 to 300 μm, the film brightness enhancement, productivity, and roll engraving productivity are excellent.

  The groove depth of the engraving groove roll used in the present invention is preferably 10 to 300 μm. Such a lower limit is more preferably 20 μm, still more preferably 100 μm. On the other hand, the upper limit is preferably 250 μm, more preferably 200 μm. The groove depth of the roll is designed in consideration of the transfer rate to the film, and can be engraved using a known engraving machine. The linear pressure when the melt-extruded polycarbonate resin composition is sandwiched between the first roll and the second roll and pressed by the two rolls is preferably 50 kg / cm or more. More preferably, it is the range of 100-200 kg / cm. If it exceeds 200 kg / cm, the film tends to be distorted on the front surface in the thickness direction due to crushing, causing curling and warping of the film, and also causing the roll axis to be distorted due to pressure. It causes a difference.

  The brightness enhancement film of the present invention is a concavo-convex shape in which the surface-shaped concavo-convex shape is regularly arranged in the width direction of the film or / and the direction perpendicular to the width direction, and the concavo-convex shape is preferably a lens shape, A lenticular type, prism type, or linear Fresnel type lens is preferable. Here, “the width direction of the film or / and the direction perpendicular to the width direction” means that the uneven shape is regularly arranged on one side in the width direction of the film or the direction perpendicular to the width direction, and the uneven shape is on one side. Includes the regular arrangement in the width direction of the film and in the direction perpendicular to the width direction on the other surface. The concavo-convex shape of the present invention includes both modes of single-sided shaping and double-sided shaping. The uneven shape of the present invention is preferably a shape having a lens function that requires higher accuracy. The concave / convex shape of the lens function includes a lens array including a so-called fly-eye lens, but more preferably a bowl-shaped lens shape, and a prism type is particularly preferable.

The moisture permeability of the brightness enhancement film of the present invention is evaluated by the moisture permeability according to JIS Z 0208. Moisture permeability is preferably from ^20g / m 2 / 24h brightness enhancement film obtained in the present invention, 15~20g ^/ m 2 ^/ 24h, more preferred. If the moisture permeability exceeds 20g / m 2 / ^24h, deflection or warpage occurs at high temperature and high humidity environment, the result is undesirable because the luminance unevenness occurs.

  The transparency of the brightness enhancement film of the present invention is evaluated by a total light transmittance value based on JIS K 7361-1. The total light transmittance value of the brightness enhancement film obtained in the present invention is preferably 85% or more, and more preferably 88% or more.

  The brightness enhancement film of the present invention preferably has a surface-shaped unevenness transfer rate of 90% or more, and more preferably 95% or more. Further, it is preferable that deformation and warping when releasing are as small as possible.

  Hereinafter, although an example is given and explained in detail, the present invention is not limited to this unless it exceeds the purpose. In addition, the performance evaluation in an Example and a comparative example followed the following method.

(1) Flowability The melt volume flow rate (MVR) of the polycarbonate resin composition was measured at 300 ° C. under a 1.2 kg load in accordance with the method described in ISO 1133.

(2) Moisture permeability According to JIS Z0208, the moisture permeability of the brightness enhancement film having a thickness of 0.3 mm was measured.

(3) Warpage The brightness increasing film was cut into a length of 80 mm and a width of 25 mm, and the amount of warpage after being treated in a 60 ° C., 90% RH atmosphere for 96 hours was measured by the method shown in FIG.

(4) Expansion coefficient The brightness expansion film was cut into a length of 80 mm and a width of 80 mm, and the expansion coefficient of the thickness after processing in a 60 ° C., 90% RH atmosphere for 96 hours was calculated by the following formula.
Expansion coefficient = {(d−d ₀ ) / d ₀ } × 100
[D ₀ is film thickness before processing, d is film thickness after processing]

(5) Total light transmittance Based on JISK7361-1, the total light transmittance value was measured.

(6) Transfer rate The brightness increasing film was cut with a microtome, and the cut surface was observed with a scanning electron microscope S-3400N manufactured by Hitachi, and the pitch and height of the shaped shape were measured. The pitch and height of the shaped shape were measured at the positions shown in FIG. FIG. 2 is an enlarged view of the vicinity of the shaping surface.

[Examples 1-5, Comparative Examples 1-3]
Various additives listed in Table 1 were mixed in blenders in various amounts in 100 parts by weight of polycarbonate resin powder produced from bisphenol A and phosgene by an interfacial condensation polymerization method. The mixture was melt-kneaded at a cylinder temperature of 280 ° C. by a single screw extruder with a vent with a screw diameter of 40 mm, and pellets were prepared by strand cutting. Furthermore, after drying the obtained pellet at 120 degreeC for 5 to 7 hours with a hot-air circulation type dryer, the extruder temperature 250-300 degreeC, die temperature 280 degreeC, and the vacuum of a vent part with a T-die extruder with a vent. The polycarbonate resin composition was extruded while maintaining the degree at 26 kPa. The width of the T die was 450 mm, and was adjusted to 350 mm width when the roll contacted by necking between the air gaps. Furthermore, adjustment was performed by the take-up speed so that the film thickness was constant. This was performed in the manner shown in FIG. That is, the second roll was a shaping roll and the first roll and the third roll were mirror rolls. All rolls had a roll diameter of 360 mm. On the second roll, V-shaped grooves were formed and shaped to the full width of the film. The V-shaped groove had a prism shape with a pitch of 50 μm, a height of 25 μm, and an apex angle of 45 °. The temperature of the 1st roll, the 2nd roll, and the 3rd roll was set as 140 ° C, 150 ° C, and 145 ° C, respectively, and the line pressure between the 1st roll and the 2nd roll was made into 8 MPa, and the extruded molten polycarbonate resin composition was narrow. Held and shaped. Finally, the film was cut at about 50 mm at both ends to obtain a polycarbonate resin brightness increasing film having a width of 250 mm and a thickness of 0.3 mm. Various evaluation results of the obtained film are shown in Table 1.

In addition, the content of each component indicated by symbols in Table 1 is as follows.
(A-1) Polycarbonate resin: Polycarbonate resin produced by interfacial condensation polymerization from bisphenol A and phosgene [Teijin Kasei Co., Ltd. Panlite (registered trademark) L-1225WL; viscosity average molecular weight is 18,600]
(A-2) Polycarbonate resin: Polycarbonate resin produced by interfacial polycondensation from bisphenol A and phosgene [Teijin Chemicals Ltd. Panlite (registered trademark) L-1225WS; viscosity average molecular weight is 20,900]
(B) ester of alcohol and fatty acid; stearic acid monoglyceride [Rikemaru S-100A manufactured by Riken Vitamin Co., Ltd.]
(C) Phosphorus stabilizer; tetrakis (2,4-di-tert-butylphenyl) -4,4′-biphenylene diphosphonite [Clariant Japan Co., Ltd. Hostanox P-EPQ]

  The brightness enhancement film comprising the polycarbonate resin composition of the present invention is excellent in transferability, releasability, and heat resistance, and is not easily changed in shape such as deflection and warpage in a high temperature and high humidity environment. It can be used as a prism film for display devices.

A Shaped Shape Height B Shaped Shape Pitch 1 T Die Lip 2 Melt Extruded Film Resin 3 Cooling Roll First Roll 4 Shaped Engraving Roll Second Roll 5 Cooling Roll Third Roll 6 Takeoff roll

Claims (5)

0.1100 to 0.40 parts by weight of an ester of an alcohol and a fatty acid with respect to 100 parts by weight of a polycarbonate resin having a viscosity average molecular weight of 1.0 × 10 ^{4 to} 2.5 × 10 ⁴ A brightness enhancement film which is a film formed from a polycarbonate resin composition comprising 001 to 0.1 parts by weight, and which has irregularities regularly arranged on the surface thereof. The brightness enhancement film according to claim 1, wherein the phosphorus stabilizer is a phosphorus compound represented by the following formula (I).

[Wherein, R ¹ to ⁴ represent a linear or branched alkyl group having 1 to 20 carbon atoms, or an aryl group having 1 to 20 carbon atoms which may be substituted with a linear or branched alkyl group. Each may be the same or different)   The regularly arranged uneven shape is at least one selected from the group consisting of a lenticular type, a prism type, and a linear Fresnel type shape having a pitch of 10 to 300 μm and a height of 10 to 300 μm. Brightness increase film.   The brightness enhancement film according to claim 1, wherein the thickness is 0.1 to 1.0 mm. ^2. The brightness enhancement film according to claim 1, wherein the moisture permeability at a thickness of 0.3 mm is 15 to 20 g / m 2/24 h (based on JIS Z 0208).

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