JP2009202547A - Method for manufacturing resin sheet and resin sheet obtained thereby - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resin sheet which has such a thickness that has an enough strength as a substrate material, has little warping and is optically excellent, and a method for manufacturing it. <P>SOLUTION: The method for manufacturing the resin sheet with a film thickness of 0.3 mm-1.0 mm is characterized by comprising a process for extruding a cyclic olefin polymer under a molten state from a die fitted on an extruder, a process for molding the cyclic olefin polymer extruded from the die into a sheet-like shape by passing it through between a metal-made endless belt with a total length of ≤500 mm supported by rolls and a cooling roll, and a process for releasing the molded sheet from the surface of the cooling roll by using a releasing roll with an outer diameter of ≥180 mmΦ. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for producing a resin sheet having excellent optical properties and a resin sheet obtained thereby.

  As an optical substrate used for an optical member such as a touch panel, use of a heat-resistant plastic plate as a substrate material has been studied. However, a plastic plate having a thickness as a substrate material is prone to warp, and when a transparent conductive layer or a hard coat layer is formed on the surface, there is a problem that these layers are cracked or peeled over time. there were. In recent years, a polarizing plate integrated type touch panel in which a touch panel substrate is combined with a polarizing plate has been studied. In order to realize this, it is essential that there is no optical distortion of the material of the touch panel substrate. The warp of the plastic plate causes optical distortion, and there is a problem that it is difficult to obtain a sheet having a small residual retardation.

Patent Document 1 discloses a method of forming a sheet with less optical distortion, a method of forming a resin sheet between a metal roll and a metal belt, and Patent Document 2 discloses a method of defining the opening degree of a die lip. And a method of manufacturing a sheet, a film or the like having a partially small residual retardation. However, a method for reducing the warpage of a thick film sheet used for a substrate material and obtaining an optically excellent sheet has not yet been achieved.
Japanese Patent Laid-Open No. 2000-219752 JP 2000-263628 A

  The present invention has been made based on the above circumstances, a resin sheet having a sufficient strength as a substrate material and having little warpage and optically excellent, and a method for producing the same. The purpose is to provide.

The method for producing a resin sheet according to the present invention includes a step of extruding a molten cyclic olefin polymer from a die attached to an extruder, and a total length of the cyclic olefin polymer extruded from the die supported by a roll. A step of forming a sheet by passing between a metal endless belt of 500 mm or less and a cooling roll, and a step of peeling the formed sheet from the surface of the cooling roll using a peeling roll having an outer diameter of 180 mmΦ or more. It is a manufacturing method of the resin sheet which has the film thickness in the range of 0.3 mm-1.0 mm characterized by including.
The cyclic olefin polymer used in the present invention is preferably a resin obtained by (co) polymerizing a monomer containing at least one compound represented by the following formula (1).

(In General Formula (1), R < ¹ > -R < ⁴ > is a hydrogen atom, a halogen atom, a C1-C30 hydrocarbon group, or another monovalent organic group, and may be the same or different. Any two of R ^{1 to} R ⁴ may be bonded to each other to form a monocyclic or polycyclic structure, m is 0 or a positive integer, and p is 0 or a positive integer. is there.)

  The resin sheet of the present invention is obtained by the production method as described above.

According to the method for producing a resin sheet of the present invention, a resin sheet with extremely small warpage and optical distortion can be produced.
The warp and optical distortion of the resin sheet of the present invention are extremely small.

Hereinafter, the present invention will be described in detail.
<Cyclic olefin polymer>
The resin sheet obtained in the present invention is made of a cyclic olefin polymer. This cyclic olefin-based polymer has thermoplasticity, and birefringence due to molecular orientation is less likely to occur when molecules are oriented compared to other thermoplastic transparent resins such as polycarbonate and polystyrene. It is useful for various applications in the field.

Examples of the cyclic olefin polymer include a polymer or copolymer (hereinafter referred to as “(copolymer)” obtained from the monomer represented by the general formula (1) (hereinafter also referred to as “specific monomer”). ) Polymer "), and specifically, polymers or copolymers (hereinafter collectively referred to as" (co) polymers ") shown in (a) to (c) below. ) Can be suitably used.
(A) Hydrogenation of a ring-opening (co) polymer of (b) (a) a ring-opening (co) polymer with a specific monomer and, if necessary, another monomer copolymerizable therewith (Co) polymer (c) addition (co) polymer of a specific monomer and, if necessary, another monomer copolymerizable therewith, among these, particularly preferably shown in (b) above A hydrogenated (co) polymer, that is, a (co) polymer having a structural unit represented by the following general formula (2) is used. Since such a hydrogenated (co) polymer has excellent thermal stability, it can prevent its properties from being deteriorated by heating when it is molded or used as a product. it can.

(In the formula, the definitions of R ^{1 to} R ⁴ , p and m are the same as those in the above formula (1).)

[Specific monomer]
As a preferable specific monomer, in the above formula (1), R ¹ and R ³ are a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms, and R ² and R ⁴ are a hydrogen atom or a monovalent organic group. And at least one of R ² and R ⁴ represents a polar group other than a hydrogen atom and a hydrocarbon group, m is an integer of 0 to 3, p is an integer of 0 to 3, and the value of m + p is 0. -4, more preferably 0-2, particularly preferably 1.

Among the specific monomers, the specific monomer in which at least one of R ² and R ⁴ has a polar group represented by the following formula (3) has a glass transition temperature (hereinafter also referred to as “Tg”). It is preferable at the point from which a cyclic olefin type polymer with high and low hygroscopic property is obtained.

^{_{- (CH 2) nCOOR 5 (}} 3)
(Wherein, R ⁵ represents a hydrocarbon group having 1 to 12 carbon atoms, n is an integer from 0 to 5.)
In the above formula (3), R ⁵ is preferably an alkyl group having 1 to ⁵ carbon atoms, particularly preferably a methyl group or an ethyl group.

Further, in the above formula (1), the smaller the value of n, the higher the Tg of the resulting cyclic olefin polymer, which is preferable. In particular, the specific monomer having n of 0 is easy to synthesize. This is preferable.
In the above formula (1), R ¹ or R ³ is preferably an alkyl group, more preferably an alkyl group having 1 to 4 carbon atoms, still more preferably an alkyl group having 1 to 2 carbon atoms, particularly A methyl group is preferred. Furthermore, it is preferable that this alkyl group is bonded to the same carbon atom as the carbon atom to which the polar group represented by the above formula (3) is bonded.

Moreover, the specific monomer whose m is 1 in the said Formula (1) is preferable at the point from which the thermoplastic resin composition with higher Tg is obtained.
As a specific example of the specific monomer represented by the above formula (1),
Bicyclo [2.2.1] hept-2-ene,
Tricyclo [4.3.0.1 ^2,5 ] -8-decene,
Tricyclo [4.4.0.1 ^2,5 ] -3-undecene,
Tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
Pentacyclo [6.5.1.1 ^3,6 . 0 ^2,7 . 0 ^9,13 ] -4-pentadecene,
5-methylbicyclo [2.2.1] hept-2-ene,
5-ethylbicyclo [2.2.1] hept-2-ene,
5-methoxycarbonylbicyclo [2.2.1] hept-2-ene,
5-methyl-5-methoxycarbonylbicyclo [2.2.1] hept-2-ene,
5-cyanobicyclo [2.2.1] hept-2-ene,
8-methoxycarbonyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8-ethoxycarbonyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8-n-propoxycarbonyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8-isopropoxycarbonyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8-n-butoxycarbonyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8-methyl-8-methoxycarbonyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8-methyl-8-ethoxycarbonyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8-methyl-8-n-propoxycarbonyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8-methyl-8-isopropoxycarbonyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8-methyl-8-n-butoxycarbonyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
5-ethylidenebicyclo [2.2.1] hept-2-ene,
8-ethylidenetetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
5-phenylbicyclo [2.2.1] hept-2-ene,
8-phenyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
5-fluorobicyclo [2.2.1] hept-2-ene,
5-fluoromethylbicyclo [2.2.1] hept-2-ene,
5-trifluoromethylbicyclo [2.2.1] hept-2-ene,
5-pentafluoroethylbicyclo [2.2.1] hept-2-ene,
5,5-difluorobicyclo [2.2.1] hept-2-ene,
5,6-difluorobicyclo [2.2.1] hept-2-ene,
5,5-bis (trifluoromethyl) bicyclo [2.2.1] hept-2-ene,
5,6-bis (trifluoromethyl) bicyclo [2.2.1] hept-2-ene,
5-methyl-5-trifluoromethylbicyclo [2.2.1] hept-2-ene,
5,5,6-trifluorobicyclo [2.2.1] hept-2-ene,
5,5,6-tris (fluoromethyl) bicyclo [2.2.1] hept-2-ene,
5,5,6,6-tetrafluorobicyclo [2.2.1] hept-2-ene,
5,5,6,6-tetrakis (trifluoromethyl) bicyclo [2.2.1] hept-2-ene,
5,5-difluoro-6,6-bis (trifluoromethyl) bicyclo [2.2.1] hept-2-ene,
5,6-difluoro-5,6-bis (trifluoromethyl) bicyclo [2.2.1] hept-2-ene,
5,5,6-trifluoro-5-trifluoromethylbicyclo [2.2.1] hept-2-ene,
5-fluoro-5-pentafluoroethyl-6,6-bis (trifluoromethyl) bicyclo [2.2.1] hept-2-ene,
5,6-difluoro-5-heptafluoro-iso-propyl-6-trifluoromethylbicyclo [2.2.1] hept-2-ene,
5-chloro-5,6,6-trifluorobicyclo [2.2.1] hept-2-ene,
5,6-dichloro-5,6-bis (trifluoromethyl) bicyclo [2.2.1] hept-2-ene,
5,5,6-trifluoro-6-trifluoromethoxybicyclo [2.2.1] hept-2-ene,
5,5,6-trifluoro-6-heptafluoropropoxybicyclo [2.2.1] hept-2-ene,
8-fluorotetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8-fluoromethyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8-difluoromethyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8-trifluoromethyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8-pentafluoroethyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8,8-difluorotetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8,9-difluorotetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8,8-bis (trifluoromethyl) tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8,9-bis (trifluoromethyl) tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8-methyl-8-trifluoromethyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8,8,9-trifluorotetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8,8,9-tris (trifluoromethyl) tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8,8,9,9-tetrafluorotetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8,8,9,9-tetrakis (trifluoromethyl) tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8,8-difluoro-9,9-bis (trifluoromethyl) tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8,9-difluoro-8,9-bis (trifluoromethyl) tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8,8,9-trifluoro-9-trifluoromethyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8,8,9-trifluoro-9-trifluoromethoxytetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8,8,9-trifluoro-9-pentafluoropropoxytetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8-fluoro-8-pentafluoroethyl-9,9-bis (trifluoromethyl) tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8,9-difluoro-8-heptafluoroiso-propyl-9-trifluoromethyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8-chloro-8,9,9-trifluorotetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8,9-dichloro-8,9-bis (trifluoromethyl) tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8- (2,2,2-trifluoroethoxycarbonyl) tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8-methyl-8- (2,2,2-trifluoroethoxycarbonyl) tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene. These can be used alone or in combination of two or more.

(Copolymerizable monomer)
Other monomers that can be copolymerized with the specific monomer include cyclic compounds such as cyclobutene, cyclopentene, cycloheptene, cyclooctene, tricyclo [5.2.1.0 ^2,6 ] -3-decene, and dicyclopentadiene. Aliphatic compounds are preferred.
The use ratio of the specific monomer and the copolymerizable monomer is preferably such that the specific monomer: copolymerizable monomer is 100: 0 to 50:50 by weight, and more preferably 100 : 0 to 60:40.

(Ring-opening polymerization catalyst)
The ring-opening polymerization reaction of the specific monomer is performed in the presence of a metathesis catalyst. The metathesis catalyst includes at least one metal compound selected from a tungsten compound, a molybdenum compound, and a rhenium compound (hereinafter referred to as “component (A)”), and a Group 1 element of the periodic table (for example, Li, Na, K). Etc.), Group 2 elements (eg Mg, Ca etc.), Group 12 elements (eg Zn, Cd, Hg etc.), Group 13 elements (eg B, Al etc.), Group 4 elements (eg Ti, Zr etc.) Or at least one compound selected from those having at least one element-carbon bond or the element-hydrogen bond (hereinafter referred to as a compound of a Group 14 element (for example, Si, Sn, Pb, etc.)). , Referred to as “component (B)”), and may contain an additive (hereinafter referred to as “component (C)”) to enhance the catalytic activity. There.

Specific examples of suitable metal compounds constituting the component (A) include metal compounds described in JP-A-1-240517 such as WCl ⁶ , MoCl ⁵ and ReOCl ³ .

Specific examples of the compound constituting the component (B) include n-C ₄ H ₉ Li, (C ₂ H ₅ ) ₃ Al, (C ₂ H ₅ ) ₂ AlCl, (C ₂ H ₅ ) _1.5 AlCl _1.5 , (C ₂ H ₅ ) AlCl ₂ , methylalumoxane, LiH and the like, compounds described in JP-A-1-240517 can be mentioned.

  As the component (C), alcohols, aldehydes, ketones, amines and the like can be preferably used, but other compounds shown in JP-A-1-240517 can be used.

[Hydrogenation]
In the hydrogenation reaction, a hydrogenation catalyst is added to a usual method, that is, a solution of a ring-opening polymer, and hydrogen gas at normal pressure to 300 atm, preferably 3 to 200 atm, is added thereto at 0 to 200 ° C., preferably 20 It is carried out by operating at ~ 180 ° C.
As a hydrogenation catalyst, what is used for the hydrogenation reaction of a normal olefinic compound can be used. Examples of the hydrogenation catalyst include heterogeneous catalysts and homogeneous catalysts.

Examples of the heterogeneous catalyst include a solid catalyst in which a noble metal catalyst material such as palladium, platinum, nickel, rhodium, and ruthenium is supported on a carrier such as carbon, silica, alumina, and titania. In addition, homogeneous catalysts include nickel naphthenate / triethylaluminum, nickel acetylacetonate / triethylaluminum, cobalt octenoate / n-butyllithium, titanocene dichloride / diethylaluminum monochloride, rhodium acetate, chlorotris (triphenylphosphine) rhodium. Dichlorotris (triphenylphosphine) ruthenium, chlorohydrocarbonyltris (triphenylphosphine) ruthenium, dichlorocarbonyltris (triphenylphosphine) ruthenium, and the like. The form of the catalyst may be powder or granular.
These hydrogenation catalysts are used in such a ratio that the ring-opening (co) polymer: hydrogenation catalyst (weight ratio) is 1: 1 × 10 ⁻⁶ to 1: 2.

  The hydrogenation rate in the hydrogenated (co) polymer suitably used in the present invention is usually 50% or more, preferably 70% or more, more preferably 90% or more, still more preferably 95% or more, particularly preferably 97% or more. It is.

The cyclic olefin polymer used in the present invention preferably has an intrinsic viscosity (ηinh) measured in chloroform at 30 ° C. of 0.2 to 5.0 dl / g.
The average molecular weight of the cyclic olefin polymer is 8,000 to 100,000 in terms of polystyrene-equivalent number average molecular weight (Mn) measured by gel permeation chromatography (GPC) and 20 in terms of weight average molecular weight (Mw). Those in the range of 3,000 to 300,000 are preferred.
Furthermore, as a glass transition temperature (Tg) of the cyclic olefin polymer used for this invention, it is 110 degreeC or more normally, Preferably it is 120-250 degreeC, Most preferably, it is 120-200 degreeC. When Tg is less than 110 ° C., it is not preferable because it is deformed by use under a high temperature condition or by secondary processing such as coating or printing. On the other hand, when Tg exceeds 250 ° C., the molding process becomes difficult, and the possibility that the resin deteriorates due to heat during the molding process increases.

<Resin sheet>
The resin sheet obtained by the production method of the present invention has a thickness of 0.3 to 1.0 mm, preferably 0.5 to 1.0 mm.
The thickness distribution of the resin sheet is usually within ± 5%, preferably within ± 4%, more preferably within ± 3%, and particularly preferably within ± 2% of the average value. If the thickness distribution exceeds ± 5%, the optical distortion increases, which is not preferable.

The resin sheet obtained in the present invention is an optical sheet having a retardation at a wavelength of 589 nm of 20 nm or less, preferably 15 nm or less, particularly preferably 10 nm or less. Furthermore, the resin sheet obtained by the present invention is preferably a transparent resin sheet having a total light transmittance of 85% or more, more preferably 90% or more, and particularly 92% or more.
Since the resin sheet obtained in the present invention has its thickness and residual retardation in a specific range,
It has excellent optical properties and can be suitably used for touch panel substrates, polarizing plates, retardation plates, diffusion plates, lenticulars, Fresnel lenses, and the like.

<Method for producing resin sheet>
In the method for producing a resin sheet in the present invention, a molten cyclic olefin polymer is extruded from a die attached to an extruder, and the cyclic olefin polymer extruded from the die is endless made of metal supported by a roll. The sheet is formed into a sheet by passing between the belt and the cooling roll, and then the formed sheet is peeled from the cooling roll using the peeling roll.

  As a method of melting the cyclic olefin polymer, a method of melting a resin by an extruder is preferable, and the molten resin is quantitatively supplied by a gear pump, and this is filtered by a metal filter or the like to remove impurities. A method of extruding while forming into a film shape is preferable.

  Examples of the method for cooling the film extruded from the die to form a sheet include a nip roll method, an electrostatic application method, an air knife method, a calendar method, a single-sided belt method, a double-sided belt method, and a three-roll method. In order to manufacture a sheet with less distortion, a sheet manufacturing apparatus called a single-side belt type, particularly a sleeve type as shown in FIG. 1, is preferably used.

  Drawing 1 is an explanatory view showing the outline in an example of the manufacture device used for the manufacturing method of the resin sheet of the present invention. In this figure, 10 is an extruder, 11 is a die attached to the tip of the extruder 10, and this die 11 is arranged so that its discharge port 12 faces downward. Further, below the die 11, the cooling roll 20 and a belt 30 made of a metal endless belt are in pressure contact with each other, and the contact end of both is positioned directly below the discharge port 12 of the die 11. Is arranged in.

  The belt 30 is held in a state of being pressed against the roll 20 and in a state where a tension is applied by a first holding roll 31 and a second holding roll 32 provided so as to be in contact with the inner surface thereof. . A temperature controller may be provided on the back side of the belt 30, and the belt 30 may be heated or cooled by the temperature controller. The resin discharged from the discharge port 12 of the die 11 passes between the roll 20 and the first holding roll 31 and is pressure-bonded to the roll 20. Further, a peeling roll 40 for peeling the cyclic olefin polymer pressure-bonded to the roll 20 from the roll 20 is arranged in parallel with the roll 20.

  As the extruder 10, any of a single screw, a twin screw, a planetary type, a kneader and the like may be used, but a single screw extruder is preferably used. Further, examples of the screw shape of the extruder include a vent type, a tip dull mage type, a full flight type, and the like, and a full flight type is preferable. The gear pump used for measuring the resin may be either an internal lubrication type or an external lubrication type, but the external lubrication type is preferred.

Examples of the filter used for filtering foreign substances include a leaf disc type, a candle filter type, a leaf type, and a screen mesh.
As the die 11, it is essential to make the resin flow inside the die uniform, and in order to maintain the uniformity of the film thickness, the pressure distribution inside the die near the die outlet should be constant in the width direction. It is essential. Manifold dies, fishtail dies, coat hanger dies, and the like can be used to satisfy such conditions, and among these, coat hanger dies are preferable. A bending lip type is preferable for adjusting the flow rate of the die. A die having a function of adjusting thickness by automatic control by a heat bolt method is particularly preferable. Installing a choke bar to adjust the flow rate or attaching a lip block to adjust the thickness creates a step in the mounting part, or traps air or the like in the gap of the mounting part. This is not preferable because it may cause generation or die line. The exit of the die 11 is preferably coated with a carbide coating such as tungsten carbide.

Examples of the material of the die 11 include SCM steel and stainless steel such as SUS, but are not limited thereto.
The die 11 has a surface plated with chromium, nickel, titanium, or the like, or a PVD (Physical Vapor Deposition) method or the like, such as TiN, TiAlN, TiC, CrN, DLC (diamond-like carbon). Those having a coating film, those having other ceramics sprayed thereon, those having the surface nitrided, and the like can be used. Such a die has a high surface hardness and a small friction with the resin, so that it is possible to prevent burnt dust and the like from being mixed into the transparent resin sheet to be obtained and to prevent the occurrence of a die line. It is preferable in that it can be performed.

  The roll 20 usually has heating means and cooling means inside, and its surface roughness is preferably 0.5 μm or less, more preferably 0.3 μm or less, and particularly preferably 0.1 μm or less. As the roll 20, it is preferable to use a metal roll plated, and a chrome plated or electroless nickel plated is particularly preferable. The outer diameter of the roll 20 is preferably 400 mmΦ or less. More preferably, it is 350 mmΦ, and more preferably 300 mmΦ or less. When the outer diameter of the roll 20 is larger than 400 mmΦ, it takes a long time until the molten resin is extruded from the die and comes into contact with the roll. Therefore, unevenness in thickness, orientation unevenness, etc. are likely to occur in the extruded resin. There is a risk of deteriorating the surface appearance of the sheet and generating a residual retardation.

  The belt 30 preferably has a thickness of 0.5 mm or less, and particularly preferably has a thickness of 0.35 mm or less. When the thickness of the belt 30 exceeds 0.5 mm, it is necessary to increase the outer shape of the holding roll that supports the belt, which is not preferable. Further, the belt 30 having a total length of 500 mm or less is used because a seamless belt can be used. In the case of using a belt having a seam, a trace of the seam may be formed on the obtained transparent resin sheet, which is not preferable. Further, it is preferable to use a belt 30 having a mirror finish with a surface roughness of 0.3 μm or less. As a material constituting the belt 30, a material plated with stainless steel, nickel, chromium, nickel, or the like can be used.

  The first holding roll 31 is arranged at a height level substantially the same as that of the roll 20 so as to be spaced apart from the roll 20 and arranged in parallel. The surface of the first holding roll 31 is preferably coated with silicone rubber or other heat-resistant elastomer, and the thickness of the coating layer is more preferably 5 to 15 mm. By providing such a coating layer, when the resin is sandwiched between the roll 20 and the belt 30, the compressive stress acting on the resin is relieved, so that an increase in phase difference due to residual strain in the obtained resin sheet is achieved. Can be prevented. Moreover, it is preferable that the 1st holding roll 31 has a heating means and a cooling means inside.

  The second holding roll 32 is arranged below the roll 20 so as to be parallel to the roll 20. The second holding roll is a contact distance adjusting roll for adjusting the contact distance between the roll 20 and the belt 30 and is provided so as to be movable in an arc shape with the central axis of the roll 20 as a reference. The second holding roll 32 may have a heating unit and a cooling unit inside.

  The peeling roll 40 is arranged so as to be arranged in parallel with the roll 20, and is a roll for peeling and cooling the sheet press-bonded to the roll 20 from the roll 20. The outer diameter of the peeling roll 40 is 180 mmΦ or more. Preferably, it is 200 mmΦ or more and 500 mmΦ or less, and more preferably 250 mmΦ or more and 400 mmΦ or less. If the outer diameter of the peeling roll 40 is less than 180 mmΦ, the time for which the sheet is in contact with the roll is short and sufficient cooling time cannot be obtained, and the resulting resin sheet may be warped or cause a residual phase difference. is there. In particular, in the thick film sheet obtained in the present invention, by setting the outer diameter of the peeling roll 40 to 180 mmΦ or more, it becomes possible to obtain a sheet having no warpage or residual phase difference very suitably.

  In FIG. 1, the molten cyclic olefin polymer 1 passes between the roll 20 and the holding roll 31 so as to be in contact with the surface of the roll 20 and the surface of the belt 30 supported by the holding rolls 31 and 32. However, in the present invention, the cyclic olefin polymer may be configured to pass between the belt 30 and a belt supported by another holding roll.

  In the above, the roll 20 and the belt 30 are preferably arranged as close to the die 11 as possible. For example, a perpendicular line connecting the discharge port 12 of the die 11 to the contact end between the roll 20 and the belt 30 is preferable. The distance D is preferably 300 mm or less, particularly preferably 250 mm or less. When the distance D exceeds 300 mm, the molten cyclic olefin polymer discharged from the discharge port 12 of the die 11 is remarkably cooled before being sandwiched between the roll 20 and the belt 30, so that the residual A phase difference due to distortion is likely to occur.

  Further, the length of the contact section between the roll 20 and the belt 30 (section in which the resin is sandwiched) is preferably 100 mm or more, and particularly preferably 250 mm or more. If this length is less than 100 mm, the resin sheet may be cooled too rapidly and may not exhibit good optical properties.

A resin sheet is manufactured by the above apparatus, for example, as follows.
Usually, before introducing the cyclic olefin polymer into the extruder, water, gas (oxygen, etc.), residual solvent, etc. contained in the resin are removed in advance so that the Tg of the resin is appropriate. The resin is dried at a suitable temperature.

  As the dryer used for drying, an inert gas circulation dryer or a vacuum dryer is preferably used. It is also preferable to use a vacuum hopper that can absorb moisture in the hopper or seal the hopper with an inert gas such as nitrogen or argon, or can be kept in a reduced pressure state in order to suppress oxygen absorption.

The extruder cylinder is preferably sealed with an inert gas such as nitrogen or argon in order to prevent the resin from being oxidized during the melt extrusion and generating a gel or the like.
The cyclic olefin polymer 1 melted by the extruder 10 is extruded into a sheet shape from the discharge port 12 of the die 11 downward in the vertical direction. The temperature distribution at the outlet of the die 11 is preferably ± 1 ° C. or less. If the temperature distribution at the outlet of the die 11 exceeds ± 2 ° C., a difference in the melt viscosity of the resin occurs, and thickness unevenness, stress distribution unevenness, etc. tend to occur, which is not preferable.

  Thereafter, the extruded cyclic olefin polymer 1 is pinched by the roll 20 and the belt 30, thereby cooling the cyclic olefin polymer. And the resin sheet 2 is manufactured when the cyclic olefin type polymer crimped | bonded to the surface of the roll 20 is peeled from the surface of the roll 20 with the roll 40 for peeling. A resin roll may be obtained by arranging a peeling roll so as to be in contact with the belt, pressing the extruded cyclic olefin polymer onto the surface of the belt, and peeling the polymer from the surface of the belt.

  In the present invention, the processing temperature of the cyclic olefin polymer, that is, the set temperature of the extruder 10 and the die 11 can discharge a molten resin with uniform fluidity from the die 11 and suppress deterioration of the resin. From the viewpoint of being able to handle, it is preferably Tg + 100 ° C. or higher and Tg + 200 ° C. or lower of the cyclic olefin polymer. When the processing temperature is less than Tg + 100 ° C., the fluidity of the resin is non-uniform, and therefore, it is not preferable because the resin sheet is not stably discharged and thickness unevenness easily occurs in the resulting resin sheet. On the other hand, when the processing temperature exceeds Tg + 200 ° C., the resin molecular chain is broken or oxidized when discharged from the die 11, so that the resin is easily deteriorated.

The surface temperature of the roll 20 is preferably a temperature at which the cyclic olefin-based resin sandwiched between the roll 20 and the belt 30 can be set to a temperature equal to or higher than Tg + 5 ° C. of the resin. When the surface temperature of the roll 20 is the above temperature, a resin sheet having excellent optical characteristics can be obtained.
For the same reason, the surface temperature of the belt 30 is preferably a temperature at which the cyclic olefin polymer sandwiched between the roll 20 and the belt 30 can be set to a temperature equal to or higher than Tg + 5 ° C. of the resin.
Specifically, the surface temperature of the roll 20 is preferably Tg-60 ° C to Tg + 20 ° C of the cyclic olefin polymer, and the surface temperature of the belt 30 is Tg-50 ° C to Tg of the cyclic olefin resin. Is preferred. The surface temperature of the roll 20 is adjusted by heating means and cooling means provided inside the roll 20. Further, the surface temperature of the belt 30 is adjusted by a temperature controller provided on the back side of the belt as necessary and a heating unit and a cooling unit provided inside the holding rolls 31 and 32 as necessary.

  Further, in the portion where the roll 20 and the belt 30 are in contact with each other, the length of the section in which the cyclic olefin polymer can be set to a temperature of Tg + 5 ° C. or more of the resin is preferably 30 mm or more, and in the range of 30 to 300 mm. More preferably. When the thickness is less than 30 mm, the effect of heating is not substantially obtained. When the thickness exceeds 300 mm, the apparatus becomes too large, which is not preferable.

  The peripheral speeds of the roll 20 and the belt 30 are preferably substantially equal, and the difference in the peripheral speed is within ± 5%, preferably within ± 1%. The peripheral speed of the outer periphery of the roll 20 and the peripheral speed of the outer periphery of the belt 30 are preferably 2 to 20 m / min, more preferably 4 to 10 m / min. When the peripheral speed is slower than 2 m / min, sheet swaying occurs between the die 11 and the roll 20 (between the air gaps), and there is a risk that streaking occurs in a direction perpendicular to the sheet flow direction. If it is faster than 20 m / min, the resin temperature when peeling the cyclic olefin polymer from the roll 20 becomes too high, which is not preferable.

  The temperature of the resin when the cyclic olefin polymer pressure-bonded to the surface of the roll 20 is peeled from the roll 20 is Tg-100 ° C to Tg-10 ° C, preferably Tg-90 ° C to Tg-20 ° C. It is preferable that If it is peeled at a temperature lower than this temperature, the appearance may be deteriorated because wrinkles are generated on the surface, and if it is peeled at a temperature higher than this temperature, the residual phase difference becomes high and it is difficult to obtain a mediocre film. There is.

  The take-up speed of the resin sheet, that is, the conveying speed of the sheet after peeling, is preferably lower than the rotational peripheral speed of the roll 20. Specifically, the rotational peripheral speed of the roll 20 is V1, and the take-up speed of the resin sheet S is V2. The ratio V2 / V1 is preferably 0.7 to 0.99, more preferably 0.75 to 0.9, and particularly preferably 0.8 to 0.85. When this ratio V2 / V1 is less than 0.7, the sheet is liable to sag. On the other hand, when this ratio V2 / V1 exceeds 0.99, excessive tension acts on the sheet, The sheet may break.

Specific examples of the present invention will be described below, but the present invention is not limited to these examples. In the following, “parts” and “%” mean “parts by weight” and “% by weight” unless otherwise specified.

[Glass transition temperature (Tg)]
Using a differential scanning calorimeter (DSC) manufactured by Seiko Instruments Inc., the glass transition temperature was measured under a nitrogen atmosphere under a temperature rising rate of 20 ° C./min.

[Residual phase difference of transmitted light]
Using a “KOBRA-CCD” manufactured by Oji Scientific Instruments Co., Ltd., the in-plane retardation (R0) when light was incident perpendicularly to the sheet was measured at a wavelength of 589 nm by the low retardation mode.

[War of sheet]
A sheet cut to a size of 400 mm × 300 mm was set on a surface plate, and a gap generated between the surface plate and the sheet was measured using a clearance gauge.

<Synthesis Example 1>
In a reaction vessel purged with nitrogen, 8-methyl-8-methoxycarbonyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene 215 parts, 35 parts of bicyclo [2.2.1] hept-2-ene as a specific monomer, 33 parts of 1-hexene as a molecular weight regulator, and toluene 750 as a solvent The solution was heated to 60 ° C. Next, 0.62 parts of a toluene solution containing 1.5 mol / l of triethylaluminum as a polymerization catalyst and tungsten hexachloride modified with t-butanol and methanol (t-butanol: methanol: tungsten) are added to the solution in the reaction vessel. = 0.35 mol: 0.3 mol: 1 mol) containing 3.7 parts of a 0.05 mol / l toluene solution, and the system was opened by heating and stirring at 80 ° C. for 3 hours. Ring-opening polymer solution was obtained by ring copolymerization reaction. This ring-opening copolymer is referred to as Resin A-1.

  The resin A-1 was extruded using a gear pump while degassing toluene, and melt filtered using a metal fiber sintered filter made by Nippon Seisen with a nominal opening of 5 μm, and 280 ° C. The resin pressed in a strand shape was passed through ion-exchanged water cleaned through a 0.2 μm PVDF filter, cooled to 50 ° C., and cut with a strand cutter to obtain pellets. The obtained pellet had a glass transition temperature (Tg) of 126 ° C. Moreover, about this resin A-1, when the number average molecular weight (Mn) and weight average molecular weight (Mw) of polystyrene conversion were measured with gel permeation chromatography (GPC, solvent; tetrahydrofuran), number average molecular weight (Mn) was measured. Was 21,000, the weight average molecular weight (Mw) was 64,000, and the molecular weight distribution (Mw / Mn) was 3.05.

<Example 1>
The resin A-1 obtained in Synthesis Example 1 was dried at 100 ° C. for 4 hours, and then 260 ° C. using a 65 mmΦ single screw extruder (GM-65: manufactured by GM Engineering Co., Ltd., screw outer diameter 65 mm, L / D = 32). And melted. While measuring this with a gear pump at a rate of 1580 cm ³ / min, it was led to a polymer filter having a nominal aperture of 10 μm to remove foreign substances in the resin. This molten resin liquid was guided to a coat hanger die having a width of 600 mm, and a film-like resin was extruded from a die having a lip opening of 1.4 mm. The set temperature of the die at this time was 250 ° C., and the discharge speed was about 90 kg / hr.
The extruded sheet is sandwiched between a cooling roll having a surface roughness of Rs ≦ 0.1 μm and a metal endless belt having a thickness of 300 μm with a sleeve touch type cooling roll (manufactured by Chiba Machine Industry Co., Ltd.). Transferred onto the sheet. The cooling roll temperature was 110 ° C., the peripheral speed of the cooling roll was 2.7 m / min, and the gap between the metal belt and the cooling roll was 0.5 mm. As the metal endless belt, a seamless belt made of SUS304 having a total length of 400 mm and a surface roughness Rs ≦ 0.2 μm was used. The outer diameters of the two holding rolls holding the belt are both 150 mmΦ, the upper holding roll circulates oil at 105 ° C inside to keep the heat, and the lower holding roll passes cooling water at 25 ° C inside. Cool with water.
A peeling roll having an outer diameter of 200 mmΦ was disposed on the downstream side (direction in which the extruded sheet is conveyed) of the cooling roll, and the obtained sheet was taken up at a constant tension of 5 kgf and a take-up speed of 2.7 m / min. . As the peeling roll, a surface coated with ceramics (WC coating) was used, and the surface roughness was Rs ≦ 0.2 μm. The set temperature of the peeling roll was 107 ° C.
The thickness of the obtained resin sheet was 1.0 mm. Tretec 7332 (manufactured by Toray Film Processing Co., Ltd.) was bonded to both surfaces of the obtained resin sheet as a polyethylene surface protective film, and was cut into a size of 400 mm × 300 mm at a pressure of 50 kg / cm ^{2 with} a cutting machine. When the warpage of the sheet was measured using the above method, it was 0.1% or less. The residual retardation was 8 nm over the entire cut sheet.

[Example 2]
In Example 1, a resin sheet having a thickness of 1.2 mm was obtained in the same manner as in Example 1 except that the outer diameter of the peeling roll was changed to 250 mmΦ and the take-up speed was changed to 2.25 m / min. The warp of the obtained resin sheet was 0.1%, and the residual retardation was 10 nm.
[Example 3]
In Example 1, a resin sheet having a thickness of 0.54 mm was obtained in the same manner as in Example 1 except that the take-up speed was 5 m / min. The warp of the obtained resin sheet was 0.1% or less, and the residual retardation was 6 nm.

[Comparative Example 1]
In Example 1, a resin sheet having a thickness of 1.0 mm was obtained in the same manner as in Example 1 except that the outer diameter of the peeling roll was changed to 100 mmΦ. The warp of the obtained resin sheet was 4.5%, and the residual phase difference was 25 nm.
[Comparative Example 2]
Change the cooling roll to a sleeve touch type roll, without using a metal endless belt, using a device in which three rolls with an outer diameter of 250 mmΦ are arranged in parallel, the temperature control temperature of the roll from the side close to the die, Resin sheets having a thickness of 1.02 mm were obtained at 110 ° C., 112 ° C., and 105 ° C. The warp of the obtained resin sheet was 0.1% or less, but the residual retardation was 200 nm.

It is a schematic diagram showing an example of the apparatus used for the manufacturing method of the resin sheet of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cyclic olefin polymer of molten state 2 Resin sheet 10 Extruder 11 Die 12 Discharge port 20 Roll 30 Metal endless belt 31 First holding roll 32 Second holding roll 40 Peeling roll

Claims (3)

  A step of extruding a molten cyclic olefin polymer from a die attached to an extruder, a metal endless belt having a total length of 500 mm or less and a cooling roll, the cyclic olefin polymer extruded from the die supported by a roll; A step of forming a sheet by passing between and a step of peeling the formed sheet from the surface of the cooling roll using a peeling roll having an outer diameter of 180 mmΦ or more. The manufacturing method of the resin sheet which exists in the range of 0.3 mm-1.0 mm. The production of a resin sheet according to claim 1, wherein the cyclic olefin polymer is a resin obtained by (co) polymerizing a monomer containing at least one compound represented by the following formula (1). Method.

(In General Formula (1), R < ¹ > -R < ⁴ > is a hydrogen atom, a halogen atom, a C1-C30 hydrocarbon group, or another monovalent organic group, and may be the same or different. Any two of R ^{1 to} R ⁴ may be bonded to each other to form a monocyclic or polycyclic structure, m is 0 or a positive integer, and p is 0 or a positive integer. is there.)   A resin sheet obtained by the production method according to claim 1.

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