JP2000280268A - Preparation of thermoplastic resin sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for preparing a thermoplastic resin sheet which exhibits small residual phase difference and has excellent optical characteristics and has a high surface smoothness and is suitable for an optical sheet. SOLUTION: A method for preparing a thermoplastic resin sheet for optical uses which has a process wherein by passing a thermoplastic resin under molten state extruded into a sheet-like condition from a die 11 fitted on an extruder 10 through between a cast drum 20 made of a metal and can endless belt 30 made of a metal being brought into press contact with the cast drum 20 along the peripheral direction, the thermoplastic resin is pressed by pinching it to bring it into press contact with the endless belt 30, is provided. In this case. The endless belt 30 is held under a condition where tension is worked by a holding roll group consisting of a plurality of rolls contg. a driving roll 41 arranged so as to be in parallel with the cast drum through the endless belt 30 and when glass transition temp. of the thermoplastic resin is Tg [ deg.C], the surface temp. of the cast drum and the surface temp. of the driving roll 41 are respectively at least Tg [ deg.C] and at most Tg+50 [ deg.C].

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a thermoplastic resin sheet for optics, and more particularly, to a thermoplastic resin having excellent optical characteristics and suitable as an optical sheet used for, for example, a liquid crystal display device. The present invention relates to a sheet manufacturing method.

[0002]

2. Description of the Related Art A liquid crystal display device generally incorporates a retardation compensator (hereinafter referred to as a "retarder"). As such a retarder, a stretched optical sheet is used. I have. In such a stretched optical sheet,
Usually, a desired retardation can be obtained by stretching an unstretched sheet such as a polymer sheet such as a polycarbonate (PC) sheet, a polyvinyl alcohol (PVA) sheet, or a polysulfone (PSf) sheet as a raw material and orienting the molecules. Can be

As a method for producing an unstretched sheet used as a raw material of a stretched optical sheet, the following method has been proposed. (1) A resin solution is prepared by dissolving the resin in a solvent, the resin solution is cast on an endless belt or a base film, and then the solvent is removed. A solvent casting method in which a layer is formed and then the resin layer is peeled off from an endless belt or a base film (see JP-A-4-301415). (2) A method in which a resin in a molten state is extruded from the T-die by using an extruder equipped with a T-die, and then pressed by a pair of rolls (see JP-A-2-61899).

[0004] However, the method (1) has a problem that the cost of manufacturing equipment and running cost of the sheet is high and the working environment is poor. In the above method (2), the obtained sheet has uneven thickness, die lines, and gear marks, and the sheet has a large residual phase difference, and thus has sufficient properties as a sheet to be used for optical applications. I can't get anything.

As a method for producing a thermoplastic resin sheet having good surface smoothness using an extruder, a thermoplastic resin in a molten state extruded from a die is charged to a first cooling roll by a charging and fixing method. There has been proposed a method of tightly fixing (see JP-A-8-132514 and JP-A-8-174632). However, in such a method, only one side of the film-like thermoplastic resin extruded from the die is cooled in advance, so that when manufacturing a thermoplastic resin sheet having a large thickness, for example, a size exceeding 300 μm. However, there is a problem in that the obtained sheet is warped, and the surface properties, particularly, the surface smoothness on the surface opposite to the surface in contact with the first cooling roll are reduced.

Further, as a method for forming a mirror surface of polypropylene (PP), a method has been proposed in which a film-like resin extruded in a molten state from a T-die is pressed in an arc shape between a cast drum and an endless metal belt. (Japanese Unexamined Patent Publication No. Hei 6-1709)
No. 19). However, with such a method, it is possible to manufacture a sheet without uneven thickness, die line, and gear mark, but it is difficult to obtain a sheet having a small residual retardation.

Further, as a method of manufacturing a thermoplastic resin sheet having a small residual retardation, a metal cooling roll and an endless metal belt are used so that the sheet winding speed is lower than the rotational peripheral speed of the metal cooling roll. In addition, a method has been proposed in which a resin in a molten state extruded from a T-die is pressed while controlling the sheet so that the sheet does not sag after peeling (see JP-A-9-290427). However, even a thermoplastic resin sheet obtained by such a method does not have a sufficiently small residual retardation and does not have a good surface smoothness as a sheet used for optical applications. .

[0008]

DISCLOSURE OF THE INVENTION The present invention has been made based on the above circumstances, and its object is to provide:
Has a small residual phase difference and excellent optical characteristics, and
It is an object of the present invention to provide a method capable of producing a thermoplastic resin sheet having high surface smoothness and suitable as an optical sheet.

[0009]

A method for producing a thermoplastic resin sheet according to the present invention comprises the steps of: forming a molten thermoplastic resin extruded into a sheet shape from a die attached to an extruder; An optical heat source having a step of sandwiching the thermoplastic resin and pressing the thermoplastic resin against the endless belt by passing the cast drum between the belt and a metal endless belt provided so as to be pressed against the circumferential direction of the cast drum. In the method for producing a plastic resin sheet, the endless belt is subjected to tension by a holding roll group including a plurality of rolls including a driving roll arranged to be aligned with the cast drum via the endless belt. When the glass transition temperature of the thermoplastic resin is Tg [° C.], the surface temperature of the cast drum and the driving temperature Each of the surface temperature of Lumpur, Tg
[° C.] or more and Tg + 50 [° C.] or less.

In the method of manufacturing a thermoplastic resin sheet according to the present invention, the holding roll group is provided with a contact distance for adjusting a contact distance between the cast drum and the endless belt provided downstream of the driving roll. After the thermoplastic resin press-fitted to the endless belt passes through the contact distance adjusting roll, a step of peeling off the thermoplastic resin from the endless belt is provided. The surface temperature of the roll is preferably Tg-50 [° C] or more and Tg [° C] or less.

Further, the method for producing a thermoplastic resin sheet according to the present invention includes a step of peeling the thermoplastic resin pressed on the cast drum from the cast drum by a peeling roll. The surface temperature is preferably Tg [° C.] or less.

Further, in the method for producing a thermoplastic resin sheet of the present invention, the endless belt has a surface roughness of 0.2 μm.
m or less.

In the method for producing a thermoplastic resin sheet of the present invention, it is preferable to use a cyclic olefin-based thermoplastic resin as the thermoplastic resin, and the cyclic olefin-based thermoplastic resin has the following general formula (I) ) Is more preferably a polymer or copolymer having a structural unit represented by the following general formula (II): It is more preferred that they are united.

[0014]

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[0015]

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[0016]

(1) Since each of the surface temperature of the cast drum and the surface temperature of the driving roll is set to a specific range equal to or higher than the glass transition temperature of the thermoplastic resin, the heat of the molten state extruded from the die. When the thermoplastic resin is sandwiched between the cast drum and the endless belt, the thermoplastic resin is not rapidly cooled, and as a result, a thermoplastic resin sheet having a small residual retardation and a high surface smoothness is obtained. can get. (2) The thermoplastic resin adhered to the endless belt passes through the contact distance adjusting roll whose surface temperature is set to a specific range equal to or lower than the glass transition temperature of the thermoplastic resin. When the thermoplastic resin sheet peeled off from the endless belt is taken off, the thermoplastic resin sheet is not stretched, whereby the resulting thermoplastic resin sheet has uneven thickness and The occurrence of phase difference unevenness and the like is prevented. (3) By setting the surface temperature of the peeling roll to a temperature equal to or lower than the glass transition temperature of the thermoplastic resin, the thermoplastic resin is peeled off from the endless belt in a state of being cooled to a sufficiently low temperature. When the thermoplastic resin sheet is taken out, the thermoplastic resin sheet is not stretched, thereby preventing the resulting thermoplastic resin sheet from being uneven in thickness and phase difference. (4) By setting the surface roughness of the endless belt to 0.2 μm or less, a thermoplastic resin sheet having a small surface roughness can be reliably obtained. (5) By using a cyclic olefin-based thermoplastic resin as the thermoplastic resin, birefringence and photoelastic birefringence due to molecular orientation are less likely to occur, and as a result, a thermoplastic resin sheet having excellent optical properties is obtained. Can be

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a method for producing an optical thermoplastic resin sheet of the present invention will be described in detail. <Production Apparatus> FIG. 1 is an explanatory view schematically showing an example of a production apparatus used in the method for producing a thermoplastic resin sheet of the present invention. In this figure, 10 is an extruder and 11 is a die, which is attached to the tip of the extruder 10. A flat die is used as the die 11, and specific examples thereof include a manifold die, a fish tail die, and a coat hanger die. Among these, a coat hanger die and a manifold die are preferable. The material of the die 11 is SC
Examples include, but are not limited to, M-based steel and stainless steel such as SUS. The die 11 has a highly polished inner surface, in particular, a tip of a die lip, and is plated with chrome, nickel, titanium, or the like on the inner surface, or a PVD (Ph).
TiN, TiAlN, TiC, CrN, DN, etc., by a physical vapor deposition method or the like.
It is preferable to use a material on which a film such as LC (diamond-like carbon) is formed, a material on which other ceramics are thermally sprayed, a material having a surface subjected to nitriding treatment, or the like. 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 obtained thermoplastic resin sheet, and to prevent a die line from being generated. Is preferred in that

In front of the die 11 (right side in the figure), a metal cast drum 20 and a metal endless metal provided so as to be pressed against a part of the peripheral surface of the cast drum 20 along the circumferential direction. A belt 30 is provided.

The casting drum 20 has a heating means and a cooling means inside, and has a surface roughness of 0.1 mm.
It is preferably 5 μm or less, particularly preferably 0.3 μm or less. When the surface roughness exceeds 0.5 μm, it becomes difficult to obtain a thermoplastic resin sheet having a small surface roughness. Further, as the cast drum 20, it is preferable to use one in which a metal roll is plated, and particularly preferably, one in which chrome plating, electroless nickel plating, or the like is applied.

As the endless belt 30, it is preferable to use a seamless belt. When an endless belt having a seam is used, traces of the seam may be formed on the obtained thermoplastic resin sheet. In addition, the endless belt 30
It is preferable to use a material whose surface is highly polished, specifically, a material having a surface roughness of 0.2 μm or less. By pressing the thermoplastic resin onto such an endless belt 30, the surface roughness is small, for example, 0.01 μm.
m or less can be obtained reliably. When the surface roughness exceeds 0.2 μm, it may be difficult to obtain a thermoplastic resin sheet having a small surface roughness. The thickness of the endless belt 30 is 0.6 to 1.2 m.
m is preferred. When the thickness is less than 0.6 mm, the belt is easily deformed. On the other hand, if the thickness exceeds 1.2 mm, the belt has low flexibility. Stainless steel or the like can be used as a material forming the endless belt 30.

This endless belt 30 is
0, a driving roll 41 provided to be in contact with the inner surface of
Roll 42 for adjusting contact distance and roll 43 for adjusting tension
The holding drum group 40 composed of
0 is held in a state where a part of the peripheral surface is pressed along the peripheral surface and a tension is applied.

The driving roll 4 in the holding roll group 40
1 is arranged right above the cast drum 20 so as to be arranged in parallel with the cast drum 20 via an endless belt 30. The driving roll 41 is for rotating and driving the endless belt 30, and has a heating unit and a cooling unit inside. The surface of the driving roll 41 is preferably coated with silicone rubber or another heat-resistant elastomer or the like, and the thickness of the coating layer is more preferably 5 to 15 mm.

By providing such a coating layer on the driving roll 41, the cast drum 20 and the endless belt 30 are provided.
Since the compression stress acting on the thermoplastic resin is reduced when the thermoplastic resin is sandwiched by the above, an increase in the phase difference due to the residual strain in the obtained thermoplastic resin sheet can be prevented. When the thickness of the coating layer is less than 5 mm, when the thermoplastic resin is sandwiched between the cast drum 20 and the endless belt 30, a large compressive stress acts on the thermoplastic resin, so that the obtained thermoplastic resin sheet The endless belt 30 may be deformed since a large compressive stress acts on the endless belt 30 easily. On the other hand, when the thickness of the coating layer exceeds 15 mm, the compressive stress acting on the thermoplastic resin becomes too small, so that the surface smoothness of the obtained thermoplastic resin sheet may decrease.

The contact distance adjusting roll 42 in the holding roll group 40 is disposed downstream of the driving roll 41, specifically, obliquely below the driving roll 41 and parallel to the driving roll 41. The contact distance adjusting roll 42 has a heating unit and a cooling unit therein, and is provided, for example, so as to be movable in an arc shape with reference to the center axis of the cast drum 20.

The tension adjusting roll 43 in the holding roll group 40 is arranged on the side of the driving roll 41 in parallel with the driving roll 41. The tension adjusting roll 43 has a heating unit and a cooling unit therein, and is provided, for example, so as to be movable in an arc shape with reference to the center axis of the cast drum 20.

Reference numeral 50 denotes a peeling roll for peeling the thermoplastic resin pressed onto the endless belt 30 from the endless belt 30. The peeling roll 50 is located downstream of the contact distance adjusting roll 42, specifically, the contact distance. It is disposed obliquely below the adjusting roll 42 and parallel to the cast drum 20.
The peeling roll 50 has a heating unit and a cooling unit inside.

In the above, the cast drum 20 and the endless belt 30 are preferably arranged as close as possible to the die 11. For example, the cast drum 20 and the endless belt 30 are connected through the discharge port 12 of the die 11. It is preferable that the distance D of the straight line connecting to the upstream contact end E is 300 mm or less, particularly 250 mm or less. When the distance D exceeds 300 mm, the molten thermoplastic resin discharged from the discharge port 12 of the die 11 is significantly cooled before being nipped by the cast drum 20 and the endless belt 30. In the obtained thermoplastic resin sheet, a phase difference due to residual strain is likely to occur, and the surface smoothness of the obtained thermoplastic resin sheet may decrease. The contact distance between the cast drum 20 and the endless belt 30 is preferably 20 cm or more,
Particularly preferably, it is 25 cm or more. This contact distance is 2
When it is less than 0 cm, the surface smoothness of the obtained thermoplastic resin sheet may decrease.

<Thermoplastic Resin> The thermoplastic resin used in the production method of the present invention is not particularly limited, but a cyclic olefin-based thermoplastic resin is preferred. Compared with other thermoplastic transparent resins such as polycarbonate and polystyrene, this cyclic olefin-based thermoplastic resin is less likely to cause birefringence due to the orientation of the molecules when the molecules are oriented, and has a small photoelastic constant. Thus, the photoelastic birefringence is less likely to occur, which is useful for various uses in the optical field. As such a cyclic olefin-based thermoplastic resin, a polymer or copolymer obtained from a monomer represented by the following general formula (III) (hereinafter, also referred to as “specific monomer”) (hereinafter, referred to as “( (Co) polymer.)
It is preferable to use a (co) polymer having a structural unit represented by the general formula (I), and more preferably a (co) polymer having a structural unit represented by the general formula (II) It is a polymer.

[0029]

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Specifically, the following polymers or copolymers (a) to (e) can be suitably used as the cyclic olefin-based thermoplastic resin. (A) a ring-opening polymer of a specific monomer (hereinafter, also referred to as “specific ring-opening polymer”), (b) a specific monomer and a cyclic monomer copolymerizable therewith (hereinafter, “ (Hereinafter, also referred to as "specific ring-opening copolymer"), (c) specific monomer and unsaturated double bond-containing (D) a specific ring-opening polymer or a specific ring-opening copolymer (hereinafter referred to as a “specific ring-opening polymer”). (Both)
Also referred to as "polymer." ) Hydrogenated (co) polymers, (e)
Hydrogenated (co) polymer obtained by cyclizing a specific ring-opened (co) polymer by Friedel-Crafts reaction and then hydrogenating

[0031] As the [specific monomer] Preferred specific monomer, in the above formula (III), a hydrocarbon group of R ¹ and R ³ is hydrogen atom or a C1-10, R ² and R ⁴ is a hydrogen atom or a monovalent organic group, 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 0 to 3 And the value of m + p is from 0 to 4, more preferably from 0 to 4.
2, particularly preferably 1.

Further, among the specific monomers, R ² and R ⁴
However, a specific monomer having a polar group represented by the following general formula (IV) is preferable because a cyclic olefin-based thermoplastic resin having a high glass transition temperature and a low hygroscopicity can be obtained.

[0033]

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In the general formula (IV), R ⁵ is preferably an alkyl group. In addition, the smaller the value of n, the higher the glass transition temperature of the obtained cyclic olefin-based thermoplastic resin, which is preferable. In particular, a specific monomer in which n is 0 is preferable because its synthesis is easy.

In the general formula (III), R ¹
Alternatively, R ³ is preferably an alkyl group, more preferably an alkyl group having 1 to 4 carbon atoms, further preferably an alkyl group having 1 to 2 carbon atoms, and particularly preferably a methyl group. Further, 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 general formula (IV) is bonded. The general formula (III)
In the above, the specific monomer in which m is 1 is preferable in that a thermoplastic resin composition having a higher glass transition temperature can be obtained.

The specific monomer represented by the above general formula (III)
Specific examples of the body include bicyclo [2.2.1] hept-
2-ene, tricyclo [5.2.1.0^2,6] -8-de
Sen, 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, pentacyclo
[7.4.0.1^2,5. 19^9,12. 0^8,13] -3-Pen
Tadecene, tricyclo [4.4.0.1^2,5] -3-C
Ndecene, 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-methoxycal
Bonylbicyclo [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-ethoxycarbo
Nyltetracyclo [4.4.0.1^2,5. 1^7,10] -3
-Dodecene, 8-n-propoxycarbonyltetracycline
B [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-butoki
Cycarbonyltetracyclo [4.4.0.1^2,5. 1
^7,10] -3-Dodecene, 8-methyl-8-methoxycal
Bonyl tetracyclo [4.4.0.1^2,5. 1 ^7,10]-
3-dodecene, 8-methyl-8-ethoxycarbonyl
Toracyclo [4.4.0.1^2,5. 1 ^7,10] -3-Dode
Sen, 8-methyl-8-n-propoxycarbonyltet
Lacyclo [4.4.0.1^{2, Five}. 1^7,10] -3-Dodece
8-methyl-8-isopropoxycarbonyltetra
Cyclo [4.4.0.1^{2, Five}. 1^7,10] -3-Dodece
8-methyl-8-n-butoxycarbonyltetracy
Black [4.4.0.1^2,5. 1^7,10-3-dodecene,

Dimethanooctahydronaphthalene, ethyltetracyclododecene, 6-ethylidene-2-tetracyclododecene, trimethanooctahydronaphthalene, pentacyclo [8.4.0.1 ^2,5 . ^19,12 . 0 ^8,13 ] −
3-hexadecene, heptacyclo [8.7.0.
^13-6 . 1 ^10,17 . 1 ^12,15 . 0 ^2,7 . 0 ^11,16 ] -4
-Eicosene, heptacyclo [8.8.0.1 ^4,7 . 1
^11,18 . 1 ^13,16 . 0 ^3,8 . 0 ^12,17 ] -5- ^heneicosene , 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-tetra Fluorobicyclo [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-hepta Fluoropropoxybicyclo [2.2.1] hept-
2-ene,

8-fluorotetracyclo [4.4.0.
1^2,5. 1^7,10] -3-dodecene, 8-fluoromethyl
Tetracyclo [4.4.0.1^2,5. 1^7,10] -3-do
Decene, 8-difluoromethyltetracyclo [4.4.
0.1^2,5. 1^7,10] -3-dodecene, 8-trifluoro
Romethyltetracyclo [4.4.0.1^2,5. 1^7,10]
-3-dodecene, 8-pentafluoroethyltetracyclic
B [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-difluoro
Tetracyclo [4.4.0.1^2,5. 1^7,10] -3-do
Decene, 8,8-bis (trifluoromethyl) tetracy
Black [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 (triflu
(Oromethyl) tetracyclo [4.4.0.1^{2, Five}. 1
^7,10] -3-dodecene, 8,8,9,9-tetrafluoro
Rotetracyclo [4.4.0.1^2,5. 1^7,10] -3-
Dodecene, 8,8,9,9-tetrakis (trifluoro
Methyl) 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-trifluoromethyltetra
Cyclo [4.4.0.1^2,5. 1^7,10] -3-Dodece
, 8,8,9-trifluoro-9-trifluorometh
Xytetracyclo [4.4.0.1^2,5. 1^7,10] -3
-Dodecene, 8,8,9-trifluoro-9-pentaf
Fluoropropoxytetracyclo [4.4.0.1^2,5.
1^7,10] -3-dodecene, 8-fluoro-8-pentaf
Fluoroethyl-9,9-bis (trifluoromethyl)
Toracyclo [4.4.0.1^2,5. 1^7,10] -3-Dode
Sen, 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-di
Chloro-8,9-bis (trifluoromethyl) tetracy
Black [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-do
Decene, 8-methyl-8- (2,2,2-trifluoro
Ethoxycarbonyl) tetracyclo [4.4.0.1
^2,5. 1^7,10] -3-dodecene, etc.
You.

Of these specific monomers, 8-methyl-
8-methoxycarbonyltetracyclo [4.4.0.1
^2,5. 1^7,10-3-Dodecene, 8-ethylidenetetra
Cyclo [4.4.0.1^2,5. 1^7,10-3-Dodese
8-ethyltetracyclo [4.4.0.1^2,5. 1
^7,10] -3-dodecene, pentacyclo [7.4.0.1
^2,5. 1^9,12. 0^8,13-3-pentadecene is excellent
A cyclic olefin-based thermoplastic resin with heat resistance can be obtained.
Is preferred in that

[Copolymerizable Cyclic Monomer] As a copolymerizable cyclic monomer for obtaining a specific ring-opening copolymer, a cycloolefin having 4 to 20, especially 5 to 12 carbon atoms is used. And specific examples thereof include cyclobutene, cyclopentene, cycloheptene, cyclooctene, tricyclo [5.2.1.0 ^2,6 ] -3-decene, 5-ethylidene-2-norbornene, dicyclopentadiene and the like. Can be

[Unsaturated Double Bond-Containing Compound] Examples of the unsaturated double bond-containing compound for obtaining a specific saturated copolymer include polybutadiene, polyisoprene, styrene-butadiene copolymer, and ethylene-nonconjugated diene copolymer. An unsaturated hydrocarbon polymer containing a carbon-carbon double bond in the main chain, such as a polymer or polynorbornene, can be used.

The ratio of the specific monomer to the copolymerizable cyclic monomer or unsaturated double bond-containing compound is determined by the specific monomer:
The weight ratio of the copolymerizable cyclic monomer or the compound having an unsaturated double bond is preferably from 100: 0 to 50:50, more preferably from 100: 0 to 60:40.
If the proportion of the copolymerizable cyclic monomer or unsaturated double bond-containing compound is excessively large, the glass transition temperature of the obtained copolymer decreases, and as a result, the heat resistance of the resin decreases. It is difficult to obtain the desired sheet having high heat resistance.

[Ring-opening polymerization catalyst] The ring-opening polymerization reaction of a specific monomer is carried out 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)”), a group IA element of the Deming periodic table (eg, Li, Na). , K, etc.), II
Group A elements (eg, Mg, Ca, etc.), Group IIB elements (eg, Zn, Cd, Hg, etc.), Group IIIB elements (eg, B,
Al, a group IVA element (eg, Ti, Zr, etc.) or a group IVB element (eg, Si, Sn, Pb, etc.) having at least one element-carbon bond or element-hydrogen bond At least one compound selected from the following (hereinafter, referred to as “component (b)”):
And an additive (hereinafter, referred to as “component (c)”) in order to enhance the catalytic activity.

Suitable Metal Compounds Constituting Component (a)
As a specific example of the material, WCl₆, MoCl_Five, ReOC
l_ThreeMetal described in JP-A-1-240517
Compounds can be mentioned. Constituting the component (b)
Specific examples of such compounds include nC_FourH₉Li, (C _Two
H_Five)_ThreeAl, (C_TwoH_Five)_TwoAlCl, (C_TwoH_Five)
_1.5AlCl_1.5, (C_TwoH_Five) AlCl_Two, Methyla
JP-A-1-240517 such as Lumoxane and LiH
The compounds described in the report can be mentioned. The above (c)
Alcohols, aldehydes, ketones,
Although amines and the like can be suitably used,
Using a compound disclosed in JP-A-1-240517
Can be

[Hydrogenation] In addition to the above specific (co) ring-opening polymer and specific saturated copolymer, specific examples of the cyclic fin-based thermoplastic resin constituting the transparent resin sheet of the present invention include: A hydrogenated (co) polymer obtained by hydrogenating a (co) ring-opened polymer, and a specific (co) ring-opened polymer obtained by cyclizing by a Friedel-Crafts reaction and then hydrogenating it Hydrogenated (co) polymers can be used. Since such a hydrogenated (co) polymer has excellent thermal stability, it is possible to prevent its properties from being deteriorated by heating when performing molding or when used as a product. it can. Here, the hydrogenation rate of the hydrogenated (co) polymer is usually 50% or more,
It is preferably at least 70%, more preferably at least 90%, further preferably at least 95%, particularly preferably at least 97%.

The cyclic olefin thermoplastic resin constituting the transparent resin sheet of the present invention has an intrinsic viscosity (η inh) of 0.2 to 5.0 dl / g measured in chloroform at 30 ° C.
It is preferred that The average molecular weight of the cyclic olefin-based thermoplastic resin is such that the number average molecular weight (Mn) in terms of polystyrene measured by gel permeation chromatography (GPC) is 8,000 to 100,000,
Weight average molecular weight (Mw) of 20,000 to 300,00
Those in the range of 0 are preferred. Further, the Vicat softening point of the cyclic olefin-based thermoplastic resin is preferably 160 ° C. or higher.

<Production Method> In the present invention, a thermoplastic resin sheet is produced by using the above-mentioned thermoplastic resin and the above-mentioned production apparatus as follows. As shown in FIG. 2, the cyclic olefin-based thermoplastic resin R melted by the extruder 10 is extruded in a sheet shape from a discharge port 12 of a die 11 in a horizontal direction (rightward in the figure). Thereafter, as shown in FIG. 3, the extruded thermoplastic resin R is passed between the cast drum 20 and the endless belt 30 so as to be squeezed by the cast drum 20 and the endless belt 30.
The thermoplastic resin R is pressed on the surface of the endless belt 30. Then, as shown in FIG. 4, after the thermoplastic resin R pressed to the surface of the endless belt 30 passes through the contact distance adjusting roll 42, the thermoplastic resin R is separated from the endless belt 30 by the peeling roll 50. The thermoplastic resin sheet S is manufactured by peeling off from the surface. This thermoplastic resin sheet S is taken off by an appropriate take-up means.

In the production method of the present invention, when the glass transition temperature of the thermoplastic resin used is Tg [° C.], the surface temperature of the cast drum 20 and the surface temperature of the driving roll 41 in the holding roll group 40 are: Tg
[° C.] or more and Tg + 50 [° C.] or less, preferably T
The temperature is set in the range of not less than g + 5 [° C.] and not more than Tg + 30 [° C.]. When the surface temperature of the cast drum 20 or the surface temperature of the drive roll 41 is lower than Tg [° C.], the thermoplastic resin R is rapidly cooled when pressed by the cast drum 20 and the endless belt 30. ,
After being extruded from the die 11, the cast drum 20
And between being pinched by the endless belt 30,
The orientation of molecules in the thermoplastic resin R caused by the tensile stress applied to the thermoplastic resin R and the compression stress applied to the thermoplastic resin R when being pressed by the cast drum 20 and the endless belt 30 It is not performed sufficiently, and as a result, a large residual retardation occurs in the obtained thermoplastic resin sheet. On the other hand, the surface temperature of the cast drum 20 or the surface temperature of the driving roll 41 is Tg + 50 [° C.].
In the case of exceeding, since the thermoplastic resin pressed on the cast drum 20 cannot be peeled off in a sufficiently cooled state, the obtained thermoplastic resin sheet has a linear shape extending in a direction perpendicular to the flow direction. Mark is generated. In addition, since the thermoplastic resin sheet is pulled off after being peeled off from the cast drum 20, molecules of the thermoplastic resin sheet are oriented due to the take-off stress, resulting in a large residual phase difference.

The surface temperature of the cast drum 20 and the surface temperature of the drive roll 41 are substantially the same, specifically, the difference between the two surface temperatures is within 20 ° C., particularly 1 ° C.
It is preferable to set the temperature to be within 0 [° C.]. When the difference between the surface temperatures of the cast drum 20 and the driving roll 41 exceeds 20 ° C., when the thermoplastic resin R is pressed by the cast drum 20 and the endless belt 30, the cast in the thermoplastic resin R Drum 2
The temperature difference between the surface in contact with zero and the surface in contact with the endless belt 30 becomes excessively large, causing a difference in shrinkage between the two, so that the thermoplastic resin sheet R obtained is warped.

The surface temperature of the contact distance adjusting roll 42 in the holding roll group 40 is not less than Tg-50 [° C.] and not more than Tg [° C.], particularly not less than Tg-30 [° C.] and not less than Tg.
It is preferable that the temperature is set in the range of −10 ° C. or less.
When the surface temperature of the contact distance adjusting roll 42 is Tg-50
When the temperature is lower than [° C.], the endless belt 30 is excessively cooled by the contact distance adjusting roll 42, so that the endless belt 30 is not sufficiently heated by the driving roll 41. As a result of rapid cooling when the resin R is pinched, a large residual retardation may occur in the obtained thermoplastic resin sheet. On the other hand, when the surface temperature of the contact distance adjusting roll 42 exceeds Tg [° C.], the thermoplastic resin bonded to the endless belt 30 is cooled to a sufficiently low temperature, for example, Tg [° C.] or less. Becomes difficult, the thermoplastic resin sheet S is stretched when the thermoplastic resin sheet S peeled off from the endless belt 30 is stretched. Become. Also,
If the surface temperature of the contact distance adjusting roll 42 is excessive,
It may be difficult to peel the thermoplastic resin R from the endless belt 30.

The surface temperature of the tension adjusting roll 43 in the holding roll group 40 is substantially the same as that of the driving roll 41, specifically, the surface temperature of the driving roll 41 is set to T.
₁ [° C], T ₁ ± 20 [° C], especially T ₁ ± 1
It is preferable to set the temperature in the range of 0 [° C.], whereby it is possible to prevent the endless belt 30 from being excessively cooled by air. The surface temperature of the tension adjusting roll 43 is T ₁
When the temperature is lower than −20 ° C., the temperature of the endless belt 30 may be significantly lowered by air cooling, and therefore, the endless belt 30 is heated to a sufficiently high temperature by the driving roll 41. Can be difficult. On the other hand, when the surface temperature of the tension adjusting roll 43 is T ₁
If the temperature exceeds +20 [° C.], the endless belt 30 may be worn.

The surface temperature of the peeling roll 50 is Tg
It is preferable to set the temperature to [° C] or lower, particularly to Tg-50 [° C] or lower. The surface temperature of the peeling roll 50 is Tg
When the temperature exceeds [° C.], it becomes difficult for the thermoplastic resin pressed on the endless belt 30 to peel off from the endless belt 30 in a state of being cooled to a sufficiently low temperature, for example, Tg [° C.] or less. When the peeled thermoplastic resin sheet S is taken out, the thermoplastic resin sheet S is stretched. As a result, the thermoplastic resin sheet S tends to have uneven thickness and uneven phase difference.

Processing temperature of thermoplastic resin, ie, extruder 1
The set temperature of 0 and the die 11 is appropriately selected according to the type of the thermoplastic resin used. For example, when a cyclic olefin-based thermoplastic resin is used as the thermoplastic resin, a resin in a molten state having a uniform fluidity can be discharged from the die 11 and, from the viewpoint of suppressing deterioration of the resin, Assuming that the glass transition temperature of the cyclic olefin-based thermoplastic resin is Tg, the glass transition temperature is preferably Tg + 100 ° C. or more and Tg + 200 ° C. or less. When the processing temperature is lower than Tg + 100 ° C., the fluidity of the cyclic olefin-based thermoplastic resin R is not uniform, so that the resin is not stably discharged from the die 11 and the obtained transparent resin sheet S has uneven thickness. It is not preferable because it becomes easy. On the other hand, when the processing temperature exceeds Tg + 200 ° C., the molecular chain of the cyclic olefin-based thermoplastic resin is cut or oxidized when discharged from the die 11, so that the cyclic olefin-based thermoplastic resin becomes It is easy to deteriorate.

The take-up speed of the thermoplastic resin sheet S is:
Preferably, the rotation peripheral speed of the cast drum 20 is lower than the rotation peripheral speed of the cast drum 20.
1. When the take-up speed of the thermoplastic 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. 0.8 to 0.85. If the ratio V2 / V1 is less than 0.7, the sheet tends to sag, while if the ratio V2 / V1 exceeds 0.99, excessive tension acts on the sheet, The sheet may be broken.

According to the above method, each of the surface temperature of the cast drum 20 and the surface temperature of the driving roll 41 in the holding roll group 40 is a specific temperature equal to or higher than the glass transition temperature (Tg) of the thermoplastic resin R. Because it is set in the range, when the thermoplastic resin R in a molten state extruded from the die 11 is sandwiched between the cast drum 20 and the endless belt 30, the thermoplastic resin R is not rapidly cooled. As a result, a thermoplastic resin sheet having a small residual retardation and high surface smoothness can be manufactured.

Further, the surface temperature of the contact distance adjusting roll 42 is set to a specific range below the glass transition temperature (Tg) of the thermoplastic resin R, and the thermoplastic resin R pressed to the endless belt 30 is contacted with the contact. Since the thermoplastic resin R is cooled to a sufficiently low temperature by passing through the distance adjusting roll 42, when the thermoplastic resin sheet S peeled off from the endless belt 30, the thermoplastic resin sheet S Without being stretched, it is possible to prevent the resulting thermoplastic resin sheet S from having uneven thickness and phase difference.

Further, by setting the surface temperature of the peeling roll 50 to a temperature equal to or lower than the glass transition temperature of the thermoplastic resin R, the thermoplastic resin R is peeled off from the endless belt 30 in a state of being cooled to a sufficiently low temperature. Therefore, when the peeled thermoplastic resin sheet S is taken out, the thermoplastic resin sheet S is not stretched, whereby uneven thickness and phase difference occur in the obtained thermoplastic resin sheet S. Can be prevented.

The thus obtained thermoplastic resin sheet has a thickness of, for example, 0.1 to 2 mm, preferably 0.2 to 2 mm.
１1 mm, surface roughness of, for example, 0.01 μm or less, preferably 0.008 μm or less, and residual phase difference of, for example, 10
nm or less and has excellent optical properties. Moreover, by using a cyclic olefin-based thermoplastic resin as a thermoplastic resin constituting the sheet, compared with other thermoplastic resins, for example, a sheet made of polystyrene, polymethyl methacrylate, and the like, birefringence is unlikely to occur. Become. Therefore, such a thermoplastic resin sheet is useful for various uses in the optical field, and is particularly suitable as an optical sheet for a liquid crystal display device.

[0060]

EXAMPLES Examples of the present invention will be specifically described below, but the present invention is not limited to these examples. In the following examples, a cyclic olefin-based thermoplastic resin “ARTON F” (manufactured by JSR Corporation) was used as the thermoplastic resin. The cyclic olefin-based thermoplastic resin is a specific ring-opened polymer having a repeating unit represented by the following formula (i),
The glass transition temperature (Tg) is 165 ° C., the number average molecular weight (Mn) in terms of polystyrene measured by gel permeation chromatography (GPC) is 25,000,
A weight average molecular weight (Mw) of 102000, an intrinsic viscosity (η _inh ) measured in chloroform of 0.49 dl / g,
The melt flow rate at 260 ° C. is 5.0 g / 10
min.

[0061]

Embedded image

Example 1 A thermoplastic resin sheet having a thickness of 0.4 mm was produced by a production apparatus having the structure shown in FIG. 1 as follows. After drying the thermoplastic resin at 120 ° C. for 4 hours with a vacuum dryer, the extruder (10)
And the extruder (10) was operated to extrude the molten thermoplastic resin (R) from the discharge port (12) of the die (11). Thereafter, the extruded thermoplastic resin (R) is cast into a cast drum (2).
0) and the endless belt (30), thereby sandwiching the cast drum (20) and the endless belt (30), and pressing the thermoplastic resin (R) on the surface of the endless belt (30). I let it. After the thermoplastic resin (R) pressed on the surface of the endless belt (30) has passed through the contact distance adjusting roll (42), the thermoplastic resin (R) is separated by the peeling roll (50). The thermoplastic resin sheet S was manufactured by peeling off from the surface of the endless belt (30). Specific conditions of the extruder (10), the die (11), the cast drum (20), the endless belt (30), the holding roll group (40), and the peeling roll (50) are shown below.

Extruder (10): Single screw extruder, cylinder inner diameter: 40 mm, screw L / D; 32, with gear pump, die (11): Coat hanger manifold type, with chrome plating on the inner surface Finished product, discharge port width; 500 mm, discharge port lip interval: 0.8 mm, extrusion processing conditions: cylinder part: 260 ° C to 300 ° C, adapter part: 290 ° C, gear pump part: 290 ° C, die: 280 ° C 18 Kg / hr, linear distance from the discharge port of the die to the upstream contact end between the cast drum and the endless belt: 240 mm, cast drum (20): surface roughness: 0.2 μm, set temperature: 175 ° C. Endless belt (30): thickness; 1 mm, surface roughness; 0.1
μm, drive roll (41): having a 10 mm thick silicone rubber coating layer, surface temperature; 1
80 ° C., contact distance adjusting roll (42): surface temperature; 135 ° C., tension adjusting roll (43): surface temperature; 180 ° C., contact distance between cast drum (20) and endless belt (30): 300 mm, Peeling roll (50): surface temperature; 100 ° C., pinching amount: 0.15 mm, peripheral speed of cast drum (20): 2 m / min, sheet take-up speed: 2 m / min

Example 2 The same procedure as in Example 1 was carried out except that the surface temperature of the cast drum (20) was changed to 205 ° C. and the surface temperature of the driving roll (41) was changed to 205 ° C. A 0.4 mm thermoplastic resin sheet was produced.

Comparative Example 1 The same procedure as in Example 1 was repeated except that the surface temperature of the cast drum (20) was changed to 140 ° C. and the surface temperature of the driving roll (41) was changed to 140 ° C. A 0.4 mm thermoplastic resin sheet was produced.

<Comparative Example 2> The thickness was reduced to 0 in the same manner as in Example 1 except that the surface temperature of the cast drum (20) was changed to 220 ° C and the surface temperature of the driving roll (41) was changed to 220 ° C. A 0.4 mm thermoplastic resin sheet was produced.

<Reference Example> Roll for adjusting contact distance (42)
Was carried out in the same manner as in Example 1 except that the temperature was changed to 190 ° C. and the surface temperature of the peeling roll (50) was changed to 180 ° C. No sheet could be produced.

[Evaluation of Thermoplastic Resin Sheet] For each of the thermoplastic resin sheets obtained in Example 1 and Comparative Example 1, the residual phase difference was measured by “KOBRA” manufactured by Oji Keisoku Co., Ltd.
-21ADH ", and the surface roughness of the surface of the thermoplastic resin sheet on the surface peeled from the endless belt was measured by" ET-30 "manufactured by Kosaka Laboratory. The results are shown in Table 1 below.

[0069]

[Table 1]

As is clear from the results shown in Table 1, it was confirmed that the thermoplastic resin sheet obtained in Example 1 had a small residual retardation and a small surface roughness. Further, it is understood that in Example 1 in which the surface temperatures of the cast drum and the driving roll are low, a thermoplastic resin sheet having extremely small surface roughness can be obtained. on the other hand,
In Example 2 in which the surface temperatures of the cast drum and the driving roll were high, some linear marks extending in the direction perpendicular to the sheet flow direction were generated, and the surface roughness was reduced in Example 1.
The value is larger than the thermoplastic resin sheet obtained in
It is understood that a thermoplastic resin sheet having an extremely small residual retardation can be obtained. On the other hand, the thermoplastic resin sheet obtained in Comparative Example 1 has a larger residual retardation and a larger surface roughness than the thermoplastic resin sheets obtained in Example 1 and Example 2. there were. Further, the thermoplastic resin sheet obtained in Comparative Example 2 had the same residual retardation as that of Example 2, but markedly formed linear marks extending in the direction perpendicular to the sheet flow direction. As a result, the surface roughness could not be measured.

[0071]

According to the first to seventh aspects of the present invention, the surface temperature of the cast drum and the surface temperature of the driving roll in the holding roll group are each set to the glass transition temperature of the thermoplastic resin. Tg) is set in the specific range or more, when the thermoplastic resin in a molten state extruded from the die is sandwiched between the cast drum and the endless belt, the thermoplastic resin may be rapidly cooled. As a result, a thermoplastic resin sheet having small residual retardation and high surface smoothness can be produced.

According to the second aspect of the present invention, the surface temperature of the contact distance adjusting roll is set to a specific range equal to or lower than the glass transition temperature (Tg) of the thermoplastic resin R, and the thermal pressure applied to the endless belt is adjusted. By passing the thermoplastic resin through the contact distance adjusting roll, the thermoplastic resin is cooled to a sufficiently low temperature, so that when the thermoplastic resin sheet peeled off from the endless belt is taken, the thermoplastic resin sheet is removed. Is not stretched, whereby it is possible to prevent the resulting thermoplastic resin sheet from having thickness unevenness and phase difference unevenness.

According to the third aspect of the invention, by setting the surface temperature of the peeling roll to a temperature equal to or lower than the glass transition temperature of the thermoplastic resin, the thermoplastic resin is cooled to a sufficiently low temperature. Since the thermoplastic resin sheet is peeled off from the endless belt, the thermoplastic resin sheet is not stretched when the peeled thermoplastic resin sheet is taken off, and thus, the resulting thermoplastic resin sheet has uneven thickness, uneven phase difference, and the like. Can be prevented from occurring.

According to the fourth aspect of the present invention, since an endless belt having a surface roughness of 0.2 μm or less is used, a thermoplastic resin is pressed on the endless belt, so that the thermoplastic resin has a small surface roughness. The resin sheet can be reliably manufactured.

According to the fifth to seventh aspects of the present invention, by using a cyclic olefin-based thermoplastic resin as the thermoplastic resin, when the molecules are oriented, birefringence due to the orientation of the molecules occurs. It is difficult to produce a thermoplastic resin sheet which is useful for various uses in the optical field, since it is difficult to generate photoelastic birefringence because the photoelastic constant is small.

[Brief description of the drawings]

FIG. 1 is an explanatory view schematically showing an example of a production apparatus used in a method for producing a thermoplastic resin sheet of the present invention.

FIG. 2 is an explanatory view showing a state where a molten thermoplastic resin is extruded from a die in the manufacturing apparatus shown in FIG.

FIG. 3 is an explanatory view showing a state in which a molten thermoplastic resin extruded from a die is pressed by a cast drum and an endless belt in the manufacturing apparatus shown in FIG.

FIG. 4 is an explanatory view showing a state in which a thermoplastic resin sheet has been peeled off from an endless belt by a peeling belt in the manufacturing apparatus shown in FIG. 1;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Extruder 11 Dice 12 Discharge port 20 Cast drum 30 Endless belt 40 Holding roll group 41 Driving roll 42 Contact distance adjusting roll 43 Tension adjusting roll 50 Peeling roll E Upstream contact end R Thermoplastic resin S Thermoplastic resin Sheet

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Hideaki Kumazawa 2-11-24 Tsukiji, Chuo-ku, Tokyo JSR Corporation F-term (reference) 4F202 AA03 AA12 AC05 AG01 AH73 AK07 AR06 AR13 CA07 CB01 CC07 4F205 AA03 AA12 AC05 AG01 AH73 AK07 AR06 AR13 GA07 GB02 GC02 GE01 GF01 GF24 GN04 GN21 GN24 GN29

Claims (7)

[Claims] 1. A molten thermoplastic resin extruded into a sheet from a die attached to an extruder is provided so as to be pressed against a metal cast drum along a circumferential direction thereof. A method for manufacturing an optical thermoplastic resin sheet having a step of sandwiching the thermoplastic resin and pressing the thermoplastic resin against the endless belt by passing between the endless belt and the metal endless belt. It is held in a state where tension is applied by a holding roll group including a plurality of rolls including a driving roll arranged in line with the cast drum via an endless belt, and the glass transition temperature of the thermoplastic resin is maintained. When the surface temperature of the cast drum and the surface temperature of the driving roll are Tg [° C.] or more and Tg [° C.]
+50 [° C.] or less, a method for producing a thermoplastic resin sheet. 2. The holding roll group includes a contact distance adjusting roll provided on a downstream side of the driving roll and configured to adjust a contact distance between the cast drum and the endless belt, and is pressed against the endless belt. After the thermoplastic resin passes through the contact distance adjusting roll, the method further includes a step of peeling the thermoplastic resin from the endless belt, wherein the surface temperature of the contact distance adjusting roll is Tg-50.
The method for producing a thermoplastic resin sheet according to claim 1, wherein the temperature is not less than [° C] and not more than Tg [° C]. 3. The method according to claim 1, further comprising the step of peeling the thermoplastic resin pressed on the endless belt from the endless belt by a peeling roll, wherein the surface temperature of the peeling roll is Tg [° C.] or lower. The method for producing a thermoplastic resin sheet according to claim 1 or 2, wherein 4. The method for producing a thermoplastic resin sheet according to claim 1, wherein the surface roughness of the endless belt is 0.2 μm or less. 5. The method for producing a thermoplastic resin sheet according to claim 1, wherein a cyclic olefin-based thermoplastic resin is used as the thermoplastic resin. 6. The thermoplastic resin sheet according to claim 5, wherein the cyclic olefin-based thermoplastic resin is a polymer or a copolymer having a structural unit represented by the following general formula (I). Manufacturing method. Embedded image 7. The thermoplastic resin sheet according to claim 5, wherein the cyclic olefin-based thermoplastic resin is a polymer or a copolymer having a structural unit represented by the following general formula (II). Manufacturing method. Embedded image