JP2002264199A - Method for manufacturing high surface hardness film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize high shearing kneading by increasing the filling ratio of a filler in the kneading of a resin and the filler, to obtain the good uniformity of the filler and to obtain a high hardness resin having high hardness and transparency as a result. SOLUTION: In the method for manufacturing the high surface hardness film by kneading the filler and the resin in a molten state to subject them to extrusion molding, a twin-screw kneading extruder is used in melt kneading.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high surface hardness film having an improved elastic modulus by including a filler in a resin, and a step of melt-kneading the filler and the resin, followed by extrusion. The present invention relates to a high surface hardness film produced by including a molding step. More specifically, the present invention relates to a method for producing a transparent substrate used for a hard coat film or an optical function film having excellent scratch resistance and surface hardness. The film produced according to the present invention may be used for a surface protection film having an optical function such as a display such as a CRT, an LCD, a PDP, and an FED, a touch panel, and glass.

[0002]

2. Description of the Related Art It is widely known that when a filler is filled in a resin, high hardness is generally known. However, it is difficult to introduce the filler into a resin having a high viscosity. Intensive research has been done to gain the character. As a kneading and extruding method, a single screw kneading extruder is known and widely used. Furthermore, in order to impart not only hardness due to high filling, but also transparency of resin,
There is a demand for finer and higher dispersion fillers.

[0003]

In kneading and extruding a resin and a filler, when the desired concentration and uniformity of the filler are to be obtained, the shearing force is small in the single screw kneading extruder described above. It is difficult to obtain sufficient kneading properties and uniformity. The present invention realizes high shear kneading with high filling of the filling material in kneading the resin and the filler, and obtains good uniformity of the filler, and as a result, high hardness having high hardness and transparency Obtaining a resin is an issue.

[0004]

A concrete means for solving the problems in the present invention is to use a twin screw kneading extruder when melt-kneading a resin and a filler. By using a twin screw kneading extruder, it has become possible to improve the uniform dispersibility of the filler, which was insufficient with the conventional method. As a result, a resin satisfying a high surface height and optical characteristics can be obtained.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail. First, polyesters such as polyethylene terephthalate, polyethylene naphthalate, copolymers of polyethylene terephthalate and polyethylene naphthalate, polybutylene terephthalate, and mixtures thereof, polycarbonates, norbornene-based resins (cyclic olefin copolymers) ), Cellulose resins such as triacetylcellulose, diacetylcellulose and the like, polyarylate, polymethyl methacrylate and the like are preferable. Of these, polyethylene terephthalate is preferred for use as a film.

As the filler used in the present invention, silica,
Examples include inorganic fine particles such as alumina, titania, zirconia, mica, talc, calcium carbonate, barium sulfate, zinc oxide, magnesium oxide, calcium sulfate, kaolin and clay, and organic fine particles such as cross-linked polystyrene and cross-linked polyacrylate ester resin. . More preferred are silica, alumina, titania, zirconia, mica, talc and clay. The shape may be any of an irregular shape, a plate shape, a spherical shape, and a needle shape, and two or more kinds of fine particles may be mixed and used. Among these, inorganic fine particles having a Moh's hardness of 6 or more, such as silica, alumina, titania, and zirconia, are preferable.

The object of the present invention is to uniformly disperse an extremely small filler at a high concentration, and the particle diameter of the filler is preferably 1 nm or more and 400 nm or less. More preferably, it is 5 nm or more and 200 nm or less, and further preferably, 5 nm or more and 100 nm or less. The particle size depends on the type of the filler, but if it is 1 nm or less, it is difficult to disperse and aggregated particles are easily formed, and if it is 400 nm or more, the haze tends to be large.

[0008] The addition amount of the filler is 5% by mass or more.
0 mass% or less is preferable. 7 mass% or more and 40 mass% or less, more preferably 10 mass% or more and 30 mass% or less. The added volume of the filler varies depending on the density (true specific gravity) of the filler.
Preferably at least 50% by volume, more preferably at least 3% by volume
The content is preferably at least 30% by volume.

In the present invention, it is desirable that the difference in the refractive index between the filler and the resin is smaller, and the refractive index of the filler is the same as that of the resin, or the difference in the refractive index of the resin is 0.5 or less, more preferably 0. .3 or less.

In order to disperse the filler uniformly in the resin,
The wettability with the resin is preferably good, and the surface is preferably modified.

In general, the inorganic fine particles have poor affinity for the binder polymer, so that the interface is easily broken simply by mixing the two, and it is difficult to improve the breaking strength. In order to improve the affinity between the inorganic fine particles and the polymer binder, the surface modifier preferably forms a bond with the inorganic fine particles on the one hand and has a high affinity for the resin on the other hand.

Representative examples of these surface modifiers are listed below. Silane coupling agent _{H 2 C = C (CH 3} ) COOC 3 H 6 Si (OCH 3)
_{3 H 2 C = CHCOOC 3 H} 6 Si (OCH 3) 3 CH 2 -CHCH 2 OC 3 H 6 Si (OCH 3) 3 \O / ( glycidyl _{group) ClCH 2 CH 2 C 3 H} 6 Si (OCH 3) _{3 ClCH 2 CH 2 CH 2 Si} (OCH 3) 3 R (OCH 2 CH 2) n OC 3 H 6 Si (OCH 3) 3 R (OCH 2 CH (CH 3)) n OC 3 H 6 Si (OC
H ₃ ) ₃ ROCO (CH ₂ ) _n Si (OCH ₃ ) ₃ (R is an alkyl group or alkenyl group having 1 to 18 carbon atoms;
And substituted alkyl _{groups, n = 1~12) CH 3 COCH} 2 COOC 3 H 6 Si (OCH 3) 3 HSCH 2 CH 2 CH 2 C 3 H 6 Si (OCH 3) 3 (CH 3 CH 2 O) 3 POC ₃ H ₆ Si (OCH ₂ CH
₃ ) ₃ etc. Titanate-based coupling agent C ₁₇ H ₃₅ COOTi (OCH (CH ₃ ) ₂ ) ₃ etc. Specifically, Aplanator (KRTTS,
KR46B, KR55, KR41B, KR38S, KR
138S, KR238S, 338X, KR44, KR9
SA)) Aluminum-based coupling agent Specifically, a saturated carboxylic acid C _n H _{2n + 1} COOH (n = 1 to ₁ ) such as Prenact AL-M (manufactured by Ajinomoto Co., Inc.)
0) CH ₃ COOH C ₂ H ₅ COOH, etc. Unsaturated carboxylic acid, oleic acid, etc. Hydroxycarboxylic acid, citric acid, tartaric acid, etc. Dibasic acid, oxalic acid, malonic acid, succinic acid, etc. Aromatic carboxylic acid, benzoic acid, etc. Terminal carboxylic acid ester compound RCOO (C _{5 H 10 COO) n H H} 2 C = CHCOO (C 5 H 10 COO) n H (R is an alkyl group having 1 to 18 carbon atoms, an alkenyl group,
Substituted alkyl groups, such as n = 1, 2, 3) Phosphoric acid monoester, phosphoric diester, and phosphonic acid RCOOC ₂ H ₄ OCOC ₅ H ₁₀ OPO (OH) ₂ (RCOOOC ₂ H ₄ OCOC ₅ H ₁₀ O) ₂ POOH (R is an alkyl group having 1 to 18 carbon atoms, an alkenyl group,
Substituted alkyl group, etc.) C ₆ H ₅ PO (OH) ₂ etc. Sulfuric acid monoester, sulfonic acid, and sulfonic acid salt CH ₃ COOC ₂ H ₄ OSO ₃ H benzenesulfonic acid dodecylbenzenesulfonic acid sodium dodecylbenzenesulfonic acid tri (isopropyl) ) polyoxyethylene alkyl ethers such as sodium naphthalene sulfonate _{C 12 H 25 (OCH 2 CH} 2) 10 OH C 9 H 19 -C 6 H 4 - (OCH 2 CH 2) 12 OH poly (polymerization degree 20) oxyethylene sorbitan Monolauric acid ester Polyoxyethylene derivative Polyoxyethylene alkyl ether Polyoxyethylene aryl ester Polyoxyethylene alkyl ester

The surface modification of these fine particles is preferably performed in a solution. Fine particles are added to the solution in which the surface modifier has been dissolved, and then ultrasonic waves, a stirrer, a homogenizer,
The treatment is preferably performed while stirring and dispersing using a dissolver, a planetary mixer, a paint shaker, a sand grinder, a kneader, or the like.

The surface modification of these inorganic fine particles is preferably carried out in a liquid layer or a solid layer. When surface modification is performed with a liquid layer, inorganic fine particles are added to a solution in which the surface modifier is dissolved, and ultrasonic waves, stirrers, homogenizers, dissolvers, agitators, planetary mixers, paint shakers, sand grinders, kneaders, colloid mills, etc. It is preferred to stir or disperse the mixture by using the above. As the solution for dissolving the surface modifier, a highly polar organic solvent is preferable, and specific examples thereof include known solvents such as alcohols, ketones, and esters. After the surface modification, the organic solvent is preferably dried by filtration or evaporation, or by a spray drier or vacuum drying.

When the surface is modified with a solid layer, inorganic fine particles are mixed with a Henschel mixer, a paddle mixer, a V-type mixer, and a W-type mixer.
It can be carried out by a method of adding a surface modifier while stirring with a mold mixer, a shaker mixer or the like. After the surface modification, a heat treatment can be performed, if necessary, to promote the reaction with the inorganic surface.

The surface-treated fine particles may be subjected to secondary agglomeration and may be pulverized. Therefore, it is preferable to pulverize the particles by a method such as an air-flow type pulverizer such as a jet mill or a ball mill.

When the resin and the filler are melted and kneaded, the resin and the filler pass through the two screw shafts and the clearance between the screw shaft and the barrel, thereby generating strong shearing and providing a good kneading condition. By using a twin-screw kneading extruder that achieves the above, good kneading properties could be achieved with high filling of the filler. More specifically, ZE40A manufactured by Berstorf Co., Ltd., KEX30, KEXP50 twin-screw continuous kneader manufactured by Kurimoto Iron Works, Ltd., HYPERKTX 46,5 manufactured by Kobe Steel, Ltd.
And a 9-axis continuous kneader.

It is preferable to mix the resin and the filler in advance. Specific methods of mixing include Henschel mixer, ribbon mixer, paddle mixer, V
Anything that can be dry-mixed, such as a mold mixer, a W mixer, or a shaker mixer, may be used. If the resin is polyethylene terephthalate, pellet the pellets at 100 ° C or higher and 25
0 ° C. or less, more preferably 130 ° C. or more and 200 ° C. or less, and 5 minutes or more and 5 hours or less, more preferably 10 minutes or more and 1 hour or less.
It is preferable to dry for not more than an hour.

The kneading temperature is preferably in the range of the temperature at which the resin softens and melts. If the temperature is too high, the surface modifier of the resin or the filler may be thermally decomposed, which is not preferable. For example, in the case of polyethylene terephthalate, the temperature is 200 ° C. or more and 350 ° C. or less, more preferably 23 ° C. or less.
The temperature is preferably from 0 ° C to 320 ° C, more preferably from 260 ° C to 300 ° C.

The kneading time is from 1 minute to 100 minutes,
More preferably, it is 2 minutes or more and 50 minutes or less, and still more preferably 3 minutes or more and 30 minutes or less. When kneading with a twin-screw kneading extruder, it is preferable to perform kneading in an inert gas atmosphere in order to prevent oxidation or thermal decomposition of a resin or a surface treating agent of a filler. As the inert gas, nitrogen gas is preferable.

It is also possible to mix the resin and the filler at a high concentration, and dilute to a predetermined filler concentration while adding the resin. Examples of the dilution method include a single-screw extruder, a twin-screw extruder, a twin-screw kneading extruder, and a Banbury mixer. It is also preferable to combine dilution and additional kneading.

The composite resin obtained by kneading and mixing the filler can be injection-molded using an extruder, formed into a sheet through a die, or further stretched into a film.

The resin containing the filler of the present invention is used in the form of a sheet or a film. These may be formed in a single layer, but can also be used in a laminate.
When making such a laminate, each component is extruded using a T-die (such as a multi-manifold die) having a laminate structure. This can be solidified on a casting drum at 40 ° C to 100 ° C to produce an unstretched film.
A resin layer containing a filler (B layer) may be laminated (B / A) on one side of a resin layer (A layer) having a smaller filler content than the B layer, and a resin layer having a smaller filler content than the B layer. (B ′ layer) may be laminated (B / A / B ′) on the A layer opposite to the B layer.

In the case of polyester terephthalate, it is preferable to further stretch after preparing an unstretched film. Improves the flatness of the film by increasing the adhesion to the casting drum by using an electrostatic application method or a water film formation method (to improve the adhesion between the melt and the drum by applying a fluid such as water on the casting drum). It is preferable. This is peeled off to form an unstretched sheet. Next, the unstretched sheet is stretched in the machine direction (MD). The preferred stretching ratio is 2.5 times or more and 4 times or less, more preferably 3 times or more and 4 times or less. The stretching temperature is preferably from 70 ° C to 160 ° C, more preferably from 80 ° C to 150 ° C, and even more preferably from 80 ° C to 140 ° C. The preferred stretching speed is 10% / sec or more and 300% / sec or less, more preferably 30% / sec or more and 250% / sec, and further preferably 50% / sec.
/ Sec or more and 200% / sec or less. Such MD stretching can be performed by transporting between a pair of rolls having different peripheral speeds. After stretching in the longitudinal direction, the film is stretched in the width direction (TD). The stretching ratio in the width direction is preferably 2.5 times or more and 5 times or less, more preferably 3 times or more and 4.5 times or less, and even more preferably 3.3 times or more and 4.3 times or less. Stretching temperature is 7
The temperature is preferably from 5 ° C to 165 ° C, more preferably 80 ° C or less.
℃ to 160 ° C, more preferably 85 ° C to 155
It is below ° C. The preferred stretching speed is 10% / second or more and 30% or more.
0% / sec or less, more preferably 30% / sec or more and 250%
/ Sec, more preferably 50% / sec or more and 200% / sec or less. TD stretching can be achieved by chucking both ends of the film, transporting the film into a tenter, and increasing the width. After stretching, the film is preferably heat-set. The heat setting temperature is 190 ° C to 275 ° C, more preferably 210 ° C to 270 ° C, and further preferably 230 ° C.
Or more and 270 ° C. or less, and a preferable treatment time is 5 seconds or more and 180 seconds or less, more preferably 10 seconds or more and 120 seconds or less, and further preferably 15 seconds or more and 60 seconds or less. It is preferable to relax in the width direction between 0% and 10% during heat setting. It is more preferably 0% or more and 8% or less, and further preferably 0% or more and 6% or less. Such heat setting and relaxation can be achieved by chucking both ends of the film, transferring the film to the heat setting zone, and reducing the width thereof. The trimming of the film end is also performed.

As a preferred mode of use, a film form is preferred. The thickness of the film is 50 μm or more and 30
It is preferably 0 μm or less, more preferably 80 μm or more and 260 μm or less. In the case of a laminated film, the thickness of the B layer and the B ′ layer is preferably 5 μm or more and 100 μm or less, more preferably 15 μm or more and 80 μm or less, and further preferably 2 μm or less.
It is 0 μm or more and 60 μm or less.

The film of the present invention is preferably subjected to a surface treatment in order to improve the adhesion when the functional layer is provided. Surface treatments include UV treatment, corona discharge treatment, glow discharge treatment, flame treatment, high frequency treatment, active plasma treatment, laser treatment, mechanical treatment, mixed acid treatment, ozone oxidation treatment and other surface activation treatments. Among the surface treatments, ultraviolet irradiation treatment, corona treatment, glow treatment, and flame treatment are preferable.

A film using a resin containing a filler may be provided with at least one undercoat layer. The structure of the undercoat layer used in the present invention has been devised in various ways. It is sufficient to provide only a layer that adheres well to the substrate as a single layer, and two or more constituent layers are further provided thereon. There is a so-called multilayer method in which a resin layer is applied. In the single layer method or the multilayer method, a resin layer containing both a hydrophobic group and a hydrophilic group may be applied.

The material which can be used for the undercoat layer is not particularly limited. For example, vinyl chloride, vinylidene chloride, butadiene, methacrylic acid, acrylic acid, itaconic acid, maleic anhydride, vinyl acetate, acrylonitrile, (meth) acrylate, styrene Examples thereof include a copolymer using a monomer selected from the above as a starting material, a hydroxyl group-containing resin such as polyvinyl alcohol and polyvinyl butyral, and a halogenated synthetic resin such as chlorinated polyethylene.

The film of the present invention can have known functions such as a hard coat layer, an antireflection layer, an antiglare layer, a selective absorption layer, an ultraviolet absorption layer, an infrared absorption layer, a conductive layer and an adhesive layer. It can be used as a functional film having a feature that the surface hardness is hard. In particular, it is suitable for use as a high-hardness functional film having a hard coat layer and an optically functional thin film such as an antireflection layer on the hard coat layer.

(Example 1) The present invention will be further described with reference to examples in which the resin is polyethylene terephthalate, but the present invention is not limited thereto. (1) Preparation of polyethylene terephthalate (PET) resin 80 parts of terephthalic acid dimethyl ester, 58 parts of ethylene glycol, 0.029 part of manganese acetate tetrahydrate and 0.028 part of antimony trioxide were added, and the mixture was stirred for 200 hours.
Heated to ° C. 235 while removing by-product methanol
The temperature was raised to ° C. After the by-product of methanol was completed, 0.03 part of trimethyl phosphoric acid was added, and the pressure was reduced to 0.3 Torr while the temperature was raised to 285 ° C. to polymerize PET having an intrinsic viscosity of 0.62. Then, it was melt-extruded into noodles and cut with a cutter to obtain polyethylene terephthalate pellets, which were further pulverized (R-1). The produced polyethylene terephthalate was vacuum-dried at 130 ° C. for 1 hour. The refractive index of PET was 1.66. In addition, the intrinsic viscosity was measured by the following method. Polyethylene terephthalate was dissolved in a phenol / 1,1,2,2-tetrachloroethane mixed solvent (weight ratio: 60/40), and 0.2 g / dl, 0.6 g / dl, and 1.
Make a solution of 0 g / dl. This is measured at 20 ° C. using an Ubbelohde viscometer. The viscosity is plotted against the concentration, and the viscosity extrapolated to the concentration = 0 is defined as the intrinsic viscosity.

2. Surface Treatment of Filler 0.4 kg of CH ₃ COO (C ₅ H ₁₀ COO) ₂ H is dissolved in 5 kg of methyl ethyl ketone, and ₂ kg of alumina (aluminum oxide C, manufactured by Nippon Aerosil Co., Ltd.) is stirred and mixed with a planetary mixer, and thereafter. The dispersion was carried out using a horizontal sand mill (media: zirconia beads of 1 mmφ). The dispersion was dried with a spray drier to prepare a surface-modified filler (P-1). The refractive index of alumina was 1.67.

3. Kneading of filler and polyethylene terephthalate The above dried polyethylene terephthalate pellets (R
-1) 8 kg of the surface-treated filler (P-1) was mixed with 2 kg of the surface-treated filler (P-1) using a Henschel mixer, and then kneaded and mixed using a twin-screw kneading extruder ZE40A manufactured by Berstorf (R-2). The kneading was carried out at a screw rotation speed of 2
00 rpm, set temperature of each zone 270 ° C processing speed;
The test was performed under the conditions of 15 kg / hr.

4. Film formation of high surface hardness film
The resin (R-2) dried under reduced pressure for 1 hour and the resin (R-1) containing no filler were melted at 300 ° C. using different extruders, filtered through a 5 μm mesh filter, and then laminated. A film was prepared by extruding from a T-die (multi-manifold die) having a structure onto a casting drum to which static electricity at 50 ° C. was applied so that the R-2 (filler-containing resin) side came into contact therewith.

This was subjected to MD stretching (3.5 times magnification, 105 times).
° C), TD stretching (4.0 times, 110 ° C), heat setting (24
(5 ° C.) and thermal relaxation to prepare a film (F-1). The total film thickness is 175 μm, and the R-1 and R-2 layers are 125 μm (A) and 50 μm (B), respectively.

5. Corona treatment Corona discharge treatment is performed using a solid surface corona treatment machine 6KVA model manufactured by Pillar Co., Ltd., and a high surface hardness film (F-
1) was processed at 20 m / min. At this time, the processing is 0.3
The treatment was performed at 75 KV · A · min / m ² . The discharge frequency during the treatment was 9.6 KHz, and the gap clearance between the electrode and the dielectric roll was 1.6 mm.

6. Preparation and Application of Undercoat Liquid An undercoat liquid for imparting adhesion between the corona-treated high surface hardness film and the hard coat layer was prepared and applied using the following materials. UV3300B (Nippon Synthetic Chemical Industry Co., Ltd. terminal acrylic-modified urethane oligomer) 5 parts by weight _{C 9 H 19 -C 6 H 4} - (OCH 2 CH 2) 12 OH 0.05 parts by weight of toluene / methyl acetate (1/1) 94.95 parts by mass These undercoat liquids were mixed at 7 ml / m using a bar coater.
² was applied to the R-2 (filler-containing layer) side, and heated and dried at 160 ° C. for 5 minutes in a heating zone while being transported. Immediately before winding, the film was cooled to 30 ° C. or lower with a cooling roller, and the prepared undercoated high surface hardness film was wound.

7. Preparation of Hard Coat Layer Coating Solution and Preparation of Hard Coat Layer As described below, a hard coat layer coating solution containing inorganic particles is prepared, subjected to coating, drying, and ultraviolet curing, and is subjected to R-2 (filler-containing layer) side. To form a hard coat layer. 7-1 Preparation of inorganic particle dispersion liquid (M-1) Methyl isobutyl ketone 234 g Aronix M5300 (oligoester acrylate polymer manufactured by Toagosei Co., Ltd.) 36 g AKP-G015 (alumina manufactured by Sumitomo Chemical Co., Ltd.) 180 g The above mixture Sand mill (1/4)
G was finely dispersed at 1600 rpm for 10 hours using a sand mill and a medium of 1 mmφ zirconia beads.

7-2 Preparation of Coating Solution for Hard Coat Layer M-1 Dispersion 3 containing 40% by mass of alumina fine particles
63 g of methanol and 124 g of isopropanol
280 g of a mixture of dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate (DPHA, manufactured by Nippon Kayaku Co., Ltd.) was added to and dissolved in the mixed solution to which g and 113 g of butyl acetate were added. Further, 16.8 g of a photopolymerization initiator (Irgacure 184, manufactured by Ciba Geigy) and 300 g of methyl isobutyl ketone were added to the obtained solution. After stirring the mixture for 30 minutes, the mixture was filtered through a polypropylene filter having a pore size of 1 μm to prepare a coating solution for a hard coat layer.

7-3 Preparation of Hard Coat Film A high-hardness resin film (F-1) provided with an undercoat layer was coated with a hard coat coating solution prepared in 7-2 using a bar coater on the surface thereof. A hard coat layer was prepared by applying and drying to 12 μm and irradiating with ultraviolet rays.

(Examples 2 to 6, and Comparative Example 1) Films were prepared by using the fillers shown in Table 1 and performing the same operations as in the examples. The refractive index of Aerosil was 1.44. Comparative Example 2 A film was prepared in the same manner as in Example 1, except that a single screw kneading extruder was used instead of the twin screw kneading extruder.

[0041]

Table 1 Dispersion of fine particles, kneading machine used and fine particle content

In each of the examples, the characteristics of the produced film and the hard coat film were evaluated as follows.

(1) Measurement of the surface elastic modulus of the film The surface elastic modulus in the present invention is the value of the elastic modulus obtained by using a micro surface hardness meter (Fisher Instruments H100VP-HCU, manufactured by Fisher Instruments Co., Ltd.). is there. Specifically, a diamond pyramid indenter (tip-to-face angle: 136 °) was used to measure the indentation depth under a test load, and the test load was applied to the geometric shape of the indenter generated by the test load. It is a value obtained from the universal hardness divided by the surface area of the indentation calculated from the above, and is a value at an indentation depth of 1 μm.

(2) The transmittance of the film was measured using a haze haze meter (Model 1001DP, manufactured by Nippon Denshoku Industries Co., Ltd.).

(3) Pencil hardness test of film The hardness of the pencil scratch test is defined by JIS-S-6006 after conditioning the prepared hard coat film at a temperature of 25 ° C and a relative humidity of 60% for 2 hours. Using a test pencil, in accordance with the pencil hardness evaluation method defined by JIS-K-5400, the value of the pencil hardness at which no scratch is observed under a load of 1 kg.

[0046]

As can be seen from Table 1, the film prepared by using the filler-containing resin obtained by kneading the filler with the twin-screw kneading extruder of the present invention does not deteriorate optical properties such as transmittance. It is apparent that the surface hardness is high and the one provided with the hard coat layer has excellent surface hardness.

[Brief description of the drawings]

FIG. 1 is an example of a preferred configuration of a high surface hardness film and a functional film of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Functional layer 2 Hard coat layer 3 Filler containing layer 4 Filler non-containing layer 5 Adhesive layer

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08L 101/00 C08L 101/00 // B29K 67:00 B29K 67:00 105: 16 105: 16 B29L 7: 00 B29L 7:00 F term (reference) 4F070 AA47 AA71 AB09 AC11 AC71 AD04 AE01 FA03 FB06 FC06 4F071 AA02 AA43 AB00 AD02 AD06 AE17 AF25 AF30 AF30Y AH19 BB06 BC01 4F207 AA24 AB11 AC01 AF16 AG01 BG01 BG01 BG01 BG03 CE001 CF061 CF071 CF081 CF161 CG001 DE076 DE096 DE106 DE136 DE146 DE236 DG046 DG056 DJ016 DJ036 DJ046 DJ056 FA012 FA016 FA072 FA076 FA082 FA086 FD012 FD016 GF00 GH00 GP00

Claims (6)

[Claims] 1. A high surface hardness film produced by melt-kneading a filler and a resin and then extruding, wherein a twin screw kneading extruder is used for melt-kneading. Production method. 2. The method for producing a high surface hardness film according to claim 1, wherein said resin is a polyester resin. 3. The method for producing a high surface hardness film according to claim 1, wherein the filler is inorganic or organic fine particles. 4. The particle size of the filler is 1 nm or more and 400 n.
The method for producing a high surface hardness film according to any one of claims 1 to 3, which is not more than m. 5. The method for producing a high surface hardness film according to claim 1, wherein the refractive index of the filler is the same as that of the resin, or the difference in the refractive index is 0.5 or less. 6. The method for producing a high surface hardness film according to claim 1, wherein the resin contains a filler in an amount of 5% by mass or more and 50% by mass or less.