JP2002113765A - Method for manufacturing norbornene-based resin film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a norbornene-based resin film showing an extremely decreased spot defect by melt extrusion. SOLUTION: A method for manufacturing a norbornene-based resin film satisfies the following condition (1); (1) a value of V/Q is not more than 3,000 wherein V is a value (cm3) of a whole volume of a filter apparatus and Q is a value (kg/hr) of an extruded amount.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a norbornene resin film by melt extrusion. The film produced by the present invention is preferably used as an optical film.

[0002]

2. Description of the Related Art Norbornene resins have the following advantages over other resins. Therefore, it is suitable as a resin raw material for optical films. (1) High heat resistance. (2) High transparency. (3) No optical rotation. (4) Low intrinsic birefringence. (5) The photoelastic coefficient is small.

However, extrusion molding of norbornene resins has been considered difficult due to poor thermal stability during melt extrusion molding. Extrusion of precision products such as optical films is particularly difficult.

A technique for improving this is disclosed in Japanese Patent No. 297727.
No. 4 (Patent gazette publication date: January 1, 1999)
January 15). According to this technique, by using a norbornene-based resin having a high number average molecular weight and a wide molecular weight distribution, a flat molded article having no residual stress can be manufactured even by melt extrusion molding.

[0005]

In general, a norbornene-based resin can be used in the air at about 260 even when an antioxidant is added.
Thermal decomposition starts at ℃. On the other hand, the melt extrusion molding temperature of the norbornene-based resin is a high temperature near 300 ° C.

Accordingly, in melt extrusion molding of norbornene-based resin, a gel-like substance is generated by thermal decomposition at a high molding temperature, so that a point defect is easily generated in a molded product.

On the other hand, norbornene-based resin films used for optical applications are required to be free from point defects. Therefore, it is very difficult to produce a norbornene resin film for optics by melt extrusion.

[0008] Usually, in melt extrusion molding, a filtration device is used to reduce point defects. By the filtration device, gel-like substances and foreign substances in the resin generated by thermal decomposition are removed or pulverized.

[0009] However, although various conditions such as filtration accuracy and filtration area have been examined from the causes inherent to the norbornene-based resin relating to thermal stability, it has been extremely difficult to find the optimum conditions for the filtration device.

In view of the above-mentioned problems, the present inventor has found a manufacturing method capable of solving the above-mentioned inherent causes by intensively studying the conditions for melt-extrusion molding of norbornene-based resins.

An object of the present invention is to provide a method for producing a norbornene-based resin film having remarkably few point defects by melt extrusion molding.

[0012]

The present invention is as follows.

1. A method for producing a norbornene-based resin film by melt extrusion molding satisfying the following condition (1). (1) The value of V / Q is 3000 or less. V is a numerical value of the volume (cm ³ ) of the entire filtering device. Q is the amount of extrusion (kg
/ Hr).

2. A method for producing a norbornene-based resin film by melt extrusion molding satisfying the following conditions (1) and (2). (1) The value of V / Q is 3000 or less. V is a numerical value of the volume (cm ³ ) of the entire filtering device. Q is the amount of extrusion (kg
/ Hr). (2) The filter medium of the filter of the filtration device has a two-layer structure composed of a metal fiber sintered body and a metal powder sintered body.

3. A method for producing an optical norbornene-based resin film by melt extrusion molding satisfying the following condition (1). (1) The value of V / Q is 3000 or less. V is a numerical value of the volume (cm ³ ) of the entire filtering device. Q is the amount of extrusion (kg
/ Hr).

4. A method for producing an optical norbornene resin film by melt extrusion molding satisfying the following conditions (1) and (2). (1) The value of V / Q is 3000 or less. V is a numerical value of the volume (cm ³ ) of the entire filtering device. Q is the amount of extrusion (kg
/ Hr). (2) The filter medium of the filter of the filtration device has a two-layer structure composed of a metal fiber sintered body and a metal powder sintered body.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.

"Norbornene resin used in the present invention" A conventionally known thermoplastic saturated norbornene resin can be used. The thermoplastic saturated norbornene resin is a resin having a norbornane skeleton in its polymerized unit.
The norbornane skeleton may have a substituent such as an alkyl group, a carboxyl group, or a phenyl group.

Known resins are disclosed in JP-A-1-240517, JP-A-62-252406, and JP-A-62-25.
2407, Japanese Patent Application Laid-Open No. 2-133413, Japanese Patent Application Laid-Open
It is described in JP-A-3-145324, JP-A-63-264626, JP-A-57-8815, and the like.

For example, there are the following resins. A hydrogenated product of a ring-opening polymer of a norbornene-based monomer, a hydrogenated product of a copolymer of two or more norbornene-based monomers, a norbornene-based monomer and an olefin-based monomer (ethylene, α
Hydrogenated product of a copolymer of a norbornene-based monomer and a cyclic olefin-based monomer (cyclopentene, cyclooctene, 5,6-dihydrodicyclopentadiene, etc.); Denatured product.

Examples of the monomer used for the thermoplastic saturated norbornene resin are as follows. Norbornene, 5-methyl-2-norbornene, 5-ethyl-2-norbornene, 5-butyl-2-norbornene, 5-ethylidene-2-norbornene, 5-methoxycarbonyl-2-norbornene, 5,5-dimethyl-2
-Norbornene, 5-cyano-2-norbornene, 5-
Methyl-5-methoxycarbonyl-2-norbornene,
5-phenyl-2-norbornene, 5-phenyl-5
Methyl-2-norbornene, ethylene-tetracyclododecene copolymer, 6-methyl-1,4: 5,8-dimetano-1,4,4a, 5,6,7,8,8a-octahydronaphthalene, 6-ethyl-1,4: 5,8-dimetano-1,4,4a, 5,6,7,8,8a-octahydronaphthalene, 6-ethyl-1,4: 5,8-ethylidene-1, 4,4a, 5,6,7,8,8a-octahydronaphthalene, 6-chloro-1,4: 5,8-dimethano-
1,4,4a, 5,6,7,8,8a-octahydronaphthalene, 6-cyano-1,4: 5,8-dimethano-
1,4,4a, 5,6,7,8,8a-octahydronaphthalene, 6-pyridyl-1,4,5,8-dimethano-
1,4,4a, 5,6,7,8,8a-octahydronaphthalene, 6-methoxycarbonyl-1,4,5,8-
Dimethano-1,4,4a, 5,6,7,8,8a-octahydronaphthalene, 1,4-dimethano-1,4,4
a, 4b, 5,8,8a, 9a-octahydrofluorene, 5,8-methano-1,2,3,4,4a, 5,8,
8a-octahydro-2,3-cyclopentadienonaphthalene, 4,9: 5,8-dimethano-3a, 4,4a,
5,8,8a, 9,9a-octahydro-1H-benzoindene, 4,11: 5,10: 6,9-trimethano-
3a, 4,4a, 5,5a, 6,9,9a, 10,10
a, 11,11a-Dodecahydro-1H-cyclopentaanthracene, 8-carboxymethyltetracyclo
[4,4,0,1 ^2,5, 1 ^7,10] -3-dodecene, 8-carboxyethyl tetracyclo [4,4,0,1 ^2,5, 1
^7,10] -3-dodecene, 8-methyl-8-carboxymethyl tetracyclo [4,4,0,1 ^2,5, 1 ^7,10] -3-dodecene.

A known method can be used for the polymerization of the norbornene-based monomer. Norbornene monomers are
If necessary, it may be copolymerized with another monomer. The resulting polymer may be hydrogenated by hydrogenation.
The polymer or the hydrogenated polymer may be modified by a known method. Examples of the compounds used for the modification are as follows.
α, β-unsaturated carboxylic acids and derivatives thereof, styrene-based hydrocarbons, olefin-based unsaturated bonds, organosilicon compounds having a hydrolyzable group, and unsaturated epoxy monomers.

The polymerization is carried out using the following polymerization catalyst. Examples of the polymerization catalyst are as follows. Ir, Os, Ru trichloride hydrate, MoCl ₅ , W
_{C1 6, ReCl 5, (C} 2 H 5) 3 Al, (C 2 H 5) 3 Al
/ TiCl ₄ , (π-C ₄ H ₇ ) ₄ Mo / TiCl ₄ , (π
_{-C 4 H 7) 4 W /} TiCl 4, (π-C 3 H 5) 3 Cr / W
Cl ₆ .

Examples of commercially available thermoplastic saturated norbornene resins are as follows. Product names "ZEONOR", "ZEON" manufactured by Zeon Corporation
EX ”; product name“ ARTO ”manufactured by JSR Corporation
N "; trade name" OPTOREZ "manufactured by Hitachi Chemical Co., Ltd .;
"APEL" manufactured by Mitsui Chemicals, Inc.

In the present invention, the weight average molecular weight (Mw) of the norbornene resin is usually from 30,000 to 150,
000, preferably 40,000 to 110,000, more preferably 50,000 to 90,000. If the weight-average molecular weight is less than 30,000, sufficient film strength cannot be obtained, so that the film breaks or tears during molding. If the weight average molecular weight exceeds 150,000, it is necessary to increase the extrusion temperature due to the high melt viscosity, so that thermal decomposition of the resin is promoted.

The molecular weight distribution of the norbornene resin (Mw /
Mn) is preferably 1.5 to 6.0, more preferably 2.0
~ 4.0. If the molecular weight distribution is less than 1.5, the resin will have poor fluidity and cannot be extruded. If the molecular weight distribution exceeds 6.0, fumes of the resin occur at the mold outlet due to the large amount of low molecular weight components.

The weight average molecular weight (Mw) and number average molecular weight (Mn) were determined by high performance liquid chromatography analysis (GPC).
Method) and the value in terms of polystyrene. The molecular weight distribution (Mw / Mn) is a value obtained by dividing the weight average molecular weight by the number average molecular weight.

The melt flow rate of the norbornene resin is usually 4 to 200 g / 10 min, preferably 10 to 15 g.
0 g / 10 min, more preferably 20 to 120 g / 10 m
in. If the melt flow rate is less than 4 g / 10 min, the fluidity of the resin will be poor and the resin will be deteriorated during extrusion. Melt flow rate is 200g / 10m
When it exceeds in, the film strength becomes weak.

The melt flow rate is determined according to JIS K721.
0 (method A). Temperature 280 ℃, load 9
8N is shown.

In the present invention, a film is produced by melt extrusion of the above-mentioned norbornene resin. A known method is used for melt extrusion.

In the present invention, a filtration device is used. This is an apparatus for filtering the melted norbornene resin with a filter. The filtration device can be used in the present invention without any particular limitation as long as it is a device usually used for extrusion molding.

Examples of the filters used in the filtering device are as follows. Disc shape filter; Candle shape filter;
Leaf disk shape filter.

In particular, a leaf disk-shaped filter is preferable for the following reasons. (1) The filtration area can be increased. (2) Structural strength can be provided. (3) The location where the molten resin stays can be reduced.

Examples of the filter medium (media) constituting the filter are as follows. (1) A filter material in which a metal wire is woven (2) A filter material obtained by sintering metal fibers (3) A filter material obtained by sintering metal powder (4) A laminate of the above filter materials.

In particular, a filter medium obtained by sintering metal fibers is preferable in terms of filtration accuracy and filtration ability. In the present invention,
Filter media obtained by laminating (2) and (3) are preferred.

The porosity of the filter medium of the above (2) is usually 35 to
95%, preferably 50-95%, more preferably 60%
~ 80%. The porosity of the filter medium of the above (3) is usually 2
It is 5 to 70%, preferably 25 to 60%, and more preferably 30 to 40%. If the porosity is small, it becomes difficult for the molten resin to pass through the filter medium, and effective filtration may not be performed. If the porosity is large, the strength of the filter medium is weakened, and the filter medium is easily broken.

The porosity indicates the percentage of the volume of the space excluding the materials such as metal fibers used from the total volume of the filter medium.

The material of the filter medium is not particularly limited. Stainless steel is preferred from the viewpoint of corrosion resistance and recycling. Particularly preferred are SUS316, 316L and 304.

The thickness of the filter medium is preferably from 0.2 to 6 mm.
More preferably, it is 0.5 to 5 mm. When the filter media are stacked, the sum of the thickness of each filter media is the thickness of the filter media. When the thickness of the filter medium is less than 0.2 mm, the effect of removing or pulverizing the gel-like substance is small, and the strength is low. When the thickness of the filter medium is larger than 6 mm, the pressure loss when the resin passes through the filter medium becomes too large.

The filtration accuracy of the filter medium is usually 100 μm or less,
Preferably it is 50 μm or less, more preferably 10 μm or less. The reason is that the size of the point defect which is a problem in the film is 100 μm or more, and when the quality is further required, it is 50 μm or more.

A plurality of filter media may be laminated. For example,
There are the following methods. In order to reinforce the strength of the filter medium, a woven wire mesh of several meshes may be laminated on the filter medium. (1) A method of installing a filter medium with a high filtration accuracy on the inlet side of the resin and installing a filter medium with a fine filtration accuracy on the outlet side of the resin. This method has an effect of roughly catching foreign matter in the first filter medium on the inlet side and preventing clogging of the filter medium on the outlet side. (2) A method of laminating a plurality of identical filter media. This method has the effect of improving the filtration accuracy.

The essential conditions of the production method of the present invention are as follows. (1) The value of V / Q is 3000 or less. V is a numerical value of the volume (cm ³ ) of the entire filtering device. Q is the amount of extrusion (kg
/ Hr).

The volume of the entire filtration device indicates the entire volume of space in which the resin can flow. That is, it indicates the volume of space including the filter, the backup plate of the filter, the introduction path to the filter, and the exit flow path of the filter. In FIG. 1, it is the total volume of the space portion (white portion) from the resin inlet side to the resin outlet side and the space portion (determined from the porosity) of the leaf disk. V means a numerical value when all the space volumes are expressed in cm ³ . When a plurality of filtration devices are used, the sum of the respective spatial volumes is the volume of the entire filtration device.

The amount of extrusion means the amount of resin discharged from the filtration device per unit time. The extrusion amount of the norbornene-based resin itself, which is a value excluding various additives. FIG.
Is the discharge amount from the resin outlet side. Q is 1
The discharge amount of norbornene resin film per hour is k
It is a numerical value when represented by g.

The value of V / Q must be less than 3000. Preferably, it is 1000 or less. If it exceeds 3,000, point defects are likely to occur.

In the present invention, a favorable effect can be obtained by adding the following conditions. (2) A laminate having a two-layer structure including a metal fiber sintered body and a metal powder sintered body is used for a filter. The laminate may be a laminate of a plurality of sheets or a sintered body. In this case, it is preferable that the filtration is performed by a metal fiber sintered body and then by a metal powder sintered body. Although the sintered metal powder has a great effect of crushing the gel-like substance, the ability to capture foreign substances is not so high. Therefore, in order to prevent clogging immediately and in some cases, the filter cannot be used, it is first filtered with a metal fiber sintered body having a high foreign matter capturing ability to remove foreign matter, and then with a metal powder sintered body. A filter material configuration that breaks the gel is preferred. Further, since the metal powder sintered body is strong in strength, if it is used on the downstream side, there is also an effect of reinforcing the metal fiber sintered body.

The average thickness of the film produced in the present invention is preferably 10 to 500 μm, more preferably 2 to 500 μm.
It is 0 to 300 μm, most preferably 20 to 100 μm. If the thickness exceeds 500 μm, point defects inside the film are hardly recognized by inspection. In particular, a point-like defect due to a colorless and transparent foreign substance such as a gel-like substance is extremely hard to be visually recognized. Therefore, from the viewpoint of easiness of visual inspection after production, the utility of the present invention is high when producing a film having a thickness in the above range. On the other hand, even when the film is thick, the present invention is highly useful because it can produce a film with few point defects due to the difficulty of visual inspection of the point defects.

Since the film produced by the present invention has few point defects, it is preferably used as an optical film. For example, by stretching a film by a known method,
A stretched film of 0 to 300 μm can be prepared and used as an optically stretched film. Since the stretched film has a small thickness, a point defect is easily recognized. In particular, since an optical film requires a point defect inspection after production, from the viewpoint of easiness of inspection, the present invention is suitably used for producing a stretching film (raw material).

[0049]

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

Example 1 Using a leaf disk-shaped filtration device, melt extrusion molding under the following conditions was carried out to obtain a width 430
mm, and a film having a thickness of 50 μm was produced. <Conditions> Norbornene resin: Trade name "ZEONOR1600R"
(Manufactured by Nippon Zeon Co., Ltd.) Preliminary drying: 110 ° C. for 3 hours Extruder: φ50 mm, L / D = 28, single screw Extrusion temperature: 275-320 ° C. Filter: leaf disk Metal fiber sintered body Filtration accuracy: 5 μm Filtration device Total volume 16000 cm ³ (V = 1600
0) Average residence time: 3 minutes T die: width 500 mm, coat hanger type Discharge amount: 20 kg / hr (Q = 20) Cooling roll temperature: 140 ° C

Example 2 A film having a width of 430 mm and a thickness of 50 μm was produced under the same conditions as in Example 1 except for the following conditions. <Conditions> Filter: Leaf disk Sintered metal powder Filtration accuracy: 12 μm

Example 3 A film having a width of 430 mm and a thickness of 50 μm was produced under the same conditions as in Example 1 except for the following conditions. <Conditions> Filter: leaf disk Two-layer structure of sintered metal fiber and sintered metal powder Filtration accuracy: sintered metal fiber 3 μm sintered metal powder 12 μm

Comparative Example 1 A film having a width of 430 mm and a thickness of 50 μm was produced under the same conditions as in Example 1 except for the following conditions. <Conditions> Volume of the entire filtration device: 64000 cm ³ (V = 6400
0)

"Evaluation" The films obtained in Examples and Comparative Examples were visually inspected. Point defects present in the area of 10 m ^{2 with} a width of 400 mm at the center of the film were counted. "Table 1"
Represents V / Q and the number of point-like defects per unit area. The point defects of the films obtained by the production methods of Examples 1 to 3 are extremely small as compared with Comparative Examples.

[0055]

[Table 1]

[0056]

According to the present invention, a norbornene-based resin film having very few point-like defects can be produced by extrusion molding.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view schematically showing a filtering device accommodating a leaf disk-shaped filter.

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Claims (3)

[Claims] 1. A method for producing a norbornene-based resin film by melt extrusion molding satisfying the following condition (1). (1) The value of V / Q is 3000 or less. V is a numerical value of the volume (cm ³ ) of the entire filtering device. Q is the extrusion rate (kg /
hr). 2. The method according to claim 1, further satisfying the following condition (2). (2) The filter medium of the filter of the filtration device has a two-layer structure composed of a metal fiber sintered body and a metal powder sintered body. 3. The method according to claim 1, wherein the norbornene-based resin film is an optical film.