JP7310417B2 - Method for manufacturing resin film - Google Patents

Description

The present invention relates to a method for producing a resin film.

A resin film formed from a resin containing a crystalline alicyclic structure polymer may be subjected to heat treatment in the production process to promote crystallization of the polymer (Patent Document 1).

WO2016/067893

When a stretched film formed from a thermoplastic resin containing a crystalline polymer is heat-treated, a resin film having poor flatness may be obtained. Moreover, when both ends of the obtained resin film were trimmed, a film with fine thread-like waste (fluff) adhering to the ends was sometimes obtained.

Therefore, there is a demand for a method for producing a resin film having excellent flatness and good edge properties after trimming from a stretched film formed from a thermoplastic resin containing a crystalline polymer.

The present inventors have conducted extensive studies to solve the above problems. As a result, the inventors have found that the problem can be solved by performing a specific cooling step after a specific heat treatment of the stretched film.
That is, the heat treatment step is performed at a specific temperature while the stretched film is held and stretched by a holder, and then the cooling step is performed at a specific temperature while holding the ends of the stretched film by the holder. Thus, the inventors have found that the above problems can be solved.
That is, the present invention provides the following.

[1] A long stretched film made of a thermoplastic resin containing a crystalline polymer is held in a tensioned state by holding two sides in the longitudinal direction of the stretched film with a holder, and the stretched film is stretched. A step (A) of processing at temperature T1 while maintaining a constant distance between the holders in the width direction;
A step (C) of cooling the stretched film at a temperature T3 while holding two sides in the longitudinal direction of the stretched film with the holding fixture,
A method for producing a resin film, wherein temperature T1 and temperature T3 satisfy the following formula.
Tg≦T1≦Tm (1)
T3≤Tg (2)
T3<T1 (3)
Here, Tg represents the glass transition temperature of the crystalline polymer, and Tm represents the melting point of the crystalline polymer.
[2] The method for producing a resin film according to [1], wherein the cooling in the step (C) is performed while reducing the distance between the holders in the width direction of the stretched film.
[3] After the step (A) and before the step (C), a step of holding two sides of the stretched film in the longitudinal direction with the holder and treating the stretched film at a temperature T2. The method for producing a resin film according to [2], further comprising (B), wherein the temperature T2 satisfies the following formula.
Tg≦T2≦Tm (4)
T3<T2<T1 (5)
[4] The method for producing a resin film according to [3], wherein the step (B) is performed while reducing the distance between the holders in the width direction of the stretched film.
[5] According to [4], wherein the reduction ratio Xb of the distance between the holders in the step (B) and the reduction ratio Xc of the distance between the holders in the step (C) satisfy the following formula: method for producing a resin film.
Xb<Xc (6)
[6] The step (B) is
A step (B1) of treating the stretched film at temperature T21 while reducing the distance between the holders in the width direction of the stretched film, and then reducing the distance between the holders in the width direction of the stretched film while temperature including a step (B2) of processing the stretched film at T22;
Here, the temperature T21 and the temperature T22 satisfy the following formula,
Tg≦T22<T21<T1 (7)
[4] or [5], wherein the reduction ratio Xb1 of the distance between the holders in the step (B1) and the reduction ratio Xb2 of the distance between the holders in the step (B2) satisfy the following formula A method for producing the described resin film.
Xb1<Xb2 (8)

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a method for producing a resin film having excellent flatness and good properties at the edges after trimming, from a stretched film formed from a thermoplastic resin containing a crystalline polymer. .

FIG. 1 is an explanatory view schematically explaining the distance between holders in the method for producing a resin film. FIG. 2 is a schematic diagram schematically showing the upper surface of a manufacturing apparatus that can be used in the resin film manufacturing method.

Hereinafter, the present invention will be described in detail by showing embodiments and examples. However, the present invention is not limited to the embodiments and examples shown below, and can be arbitrarily modified without departing from the scope of the claims of the present invention and their equivalents.

In the following description, a "long" film refers to a film having a length of 5 times or more, preferably 10 times or more, with respect to the width, specifically a roll A film that is long enough to be rolled up into a shape and stored or transported. The upper limit of the length of the film is not particularly limited, and can be, for example, 100,000 times or less the width.

In the following description, the terms “parallel”, “perpendicular” and “perpendicular” in the directions of the elements are within a range that does not impair the effects of the present invention, such as ±3°, ±2° or ±1°, unless otherwise specified. may contain an error within the range of

In the following description, the width direction is a direction perpendicular to the longitudinal direction of the long film. The longitudinal direction of a long film usually coincides with the transport direction of the film.

[1. Overview of resin film manufacturing method]
The present invention is a method for producing a resin film from a stretched film made of a thermoplastic resin containing a crystalline polymer. A manufacturing method according to an embodiment of the present invention includes steps (A) and (C) in this order. In step (A), two longitudinal sides of the stretched film are held and stretched by holders, and the stretched film is treated at temperature T1 while maintaining a constant distance between the holders in the width direction of the stretched film. In the step (C), the stretched film is cooled at a temperature T3 while two longitudinal sides of the stretched film are held by holders.
According to the production method, it is possible to produce a resin film having excellent flatness and having good edge properties after trimming.

The manufacturing method according to one embodiment of the present invention may further include step (B) after step (A) and before step (C).
In the step (B), two sides of the stretched film in the longitudinal direction are held by a holder, and the stretched film is treated at temperature T2.

[1.1. stretched film]
(Material for forming stretched film)
The thermoplastic resin forming the stretched film contains a crystalline polymer. Here, the "polymer having crystallinity" means a polymer having a melting point Tm. It can be confirmed that the polymer has a melting point Tm using a differential scanning calorimeter (DSC).
Although the melting point of the crystalline polymer is not particularly limited, it is preferably 200° C. or higher, more preferably 230° C. or higher, and preferably 290° C. or lower.
Although the glass transition temperature of the polymer having crystallinity is not particularly limited, it is, for example, 70° C. or higher, 75° C. or higher, or 85° C. or higher and, for example, 170° C. or lower.

Examples of crystalline polymers include crystalline polyolefins (e.g., polyethylene, polypropylene); crystalline alicyclic structure-containing polymers (e.g., norbornene-based polymers); crystalline cellulose esters. Polyvinyl chloride with crystallinity; Polyvinyl alcohol with crystallinity; Polystyrene with crystallinity; Polyester with crystallinity (e.g., polyethylene terephthalate, polybutylene terephthalate); Polyamide with crystallinity crystalline polyacetal; crystalline polycarbonate; crystalline polyphenylene sulfide; crystalline polyarylate; and crystalline polyetheretherketone. Among them, a crystalline alicyclic structure-containing polymer is preferable because it is excellent in mechanical strength, heat resistance, moisture resistance, and the like.

The alicyclic structure-containing polymer is a polymer having an alicyclic structure in its molecule, and is a polymer obtained by a polymerization reaction using a cyclic olefin as a monomer or a hydrogenated product thereof. In addition, the alicyclic structure-containing polymer may be used singly or in combination of two or more at any ratio.

The alicyclic structure possessed by the alicyclic structure-containing polymer includes, for example, a cycloalkane structure and a cycloalkene structure. Among these, a cycloalkane structure is preferable because a resin film having excellent properties such as thermal stability can be easily obtained. The number of carbon atoms contained in one alicyclic structure is preferably 4 or more, more preferably 5 or more, preferably 30 or less, more preferably 20 or less, and particularly preferably 15 or less. be. When the number of carbon atoms contained in one alicyclic structure is within the above range, mechanical strength, heat resistance, and moldability are highly balanced.

In the alicyclic structure-containing polymer, the ratio of structural units having an alicyclic structure to all structural units is preferably 30% by weight or more, more preferably 50% by weight or more, and particularly preferably 70% by weight or more. . Heat resistance can be improved by increasing the ratio of structural units having an alicyclic structure in the alicyclic structure-containing polymer as described above.
In addition, in the alicyclic structure-containing polymer, the remainder other than structural units having an alicyclic structure is not particularly limited and can be appropriately selected according to the purpose of use.

Examples of the alicyclic structure-containing polymer include the following polymers (α) to (δ). Among these, the polymer (β) is preferable as the crystalline alicyclic structure-containing polymer because a resin film having excellent heat resistance can be easily obtained.
Polymer (α): A ring-opening polymer of a cyclic olefin monomer and having crystallinity.
Polymer (β): A hydrogenated product of polymer (α) and having crystallinity.
Polymer (γ): A crystalline addition polymer of cyclic olefin monomers.
Polymer (δ): A hydrogenated product of polymer (γ) and having crystallinity.

Specifically, the alicyclic structure-containing polymer includes a ring-opening polymer of dicyclopentadiene having crystallinity, and a hydrogenated product of a ring-opening polymer of dicyclopentadiene and having crystallinity. Those having crystallinity are more preferable, and those which are hydrogenated products of ring-opening polymers of dicyclopentadiene and have crystallinity are particularly preferable. Here, the ring-opening polymer of dicyclopentadiene means that the ratio of structural units derived from dicyclopentadiene to all structural units is usually 50% by weight or more, preferably 70% by weight or more, more preferably 90% by weight or more, Generally, it refers to a polymer in which the ratio of structural units derived from dicyclopentadiene to all structural units is 100% by weight or less.

The hydride of the ring-opening polymer of dicyclopentadiene preferably has a high ratio of racemo dyads. Specifically, the ratio of the racemo dyad of the structural units in the hydrogenated product of the ring-opening polymer of dicyclopentadiene is preferably 51% or more, more preferably 70% or more, and particularly preferably 85% or more. A high proportion of racemo dyads indicates high syndiotactic stereoregularity. Therefore, the melting point of the hydrogenated product of the ring-opening polymer of dicyclopentadiene tends to increase as the ratio of the racemo diad increases.
The ratio of racemo dyads can be determined based on the ¹³ C-NMR spectrum analysis described in the Examples below.

In the thermoplastic resin forming the stretched film, the proportion of the crystalline polymer is preferably 50% by weight or more, more preferably 70% by weight or more, and particularly preferably 90% by weight or more. By setting the ratio of the polymer having crystallinity to the lower limit of the above range or higher, the heat resistance of the resin film can be enhanced.

The thermoplastic resin forming the stretched film may contain optional components in addition to the polymer having crystallinity.

(Method for producing stretched film)
The stretched film can be produced by any method from the thermoplastic resin containing the crystalline polymer. For example, raw film is manufactured from thermoplastic resin by resin molding methods such as injection molding, extrusion molding, press molding, inflation molding, blow molding, calendar molding, cast molding, and compression molding. Then, the raw film can be stretched to produce a stretched film. It is preferable to manufacture the raw film by an extrusion molding method because the thickness can be easily controlled.

The method of stretching the original film is not particularly limited, and any stretching method can be used. For example, uniaxial stretching methods such as a method of uniaxially stretching the original film in the longitudinal direction (longitudinal uniaxial stretching method), a method of uniaxially stretching the original film in the width direction (horizontal uniaxial stretching method); Biaxial stretching methods such as a simultaneous biaxial stretching method in which the raw film is stretched in the width direction at the same time, and a sequential biaxial stretching method in which the original film is stretched in one of the longitudinal direction and the width direction and then stretched in the other; A method of stretching in an oblique direction that is neither parallel nor perpendicular to the width direction (diagonal stretching method);

The thickness of the stretched film can be arbitrarily set according to the thickness of the resin film, but is preferably 5 μm or more, more preferably 10 μm or more, and preferably 1 mm or less, more preferably 500 μm or less.

[1.2. Step (A)]
In step (A), two longitudinal sides of the stretched film are held and stretched by holders, and the stretched film is treated at temperature T1 while maintaining a constant distance between the holders in the width direction of the stretched film. This step can promote crystallization of the crystalline polymer contained in the stretched film while suppressing deformation of the stretched film.

The state in which the stretched film is stretched refers to the state in which tension is applied to the stretched film. However, the state in which the stretched film is stretched does not include the state in which the stretched film is substantially further stretched. Further, the term "substantially stretched" means that the stretching ratio in any direction of the stretched film is usually 1.1 times or more.

The holder for holding the stretched film may be one capable of continuously holding the sides of the stretched film in the longitudinal direction, or may be one capable of intermittently holding the sides at intervals. Usually, the holders for holding the stretched film include a first holder that holds one side in the longitudinal direction of the stretched film and conveys the stretched film downstream, and a first holder that holds the other side and conveys the stretched film downstream. and a second carrier for carrying.

FIG. 1 is an explanatory diagram schematically showing the distance between holders in the method for producing a resin film.
As shown in FIG. 1, in one embodiment, the stretched film 1 is conveyed while its ends are held by a first holder 2R and a second holder 2L. The first holder 2R and the second holder 2L move downstream along the trajectories 3R and 3L, respectively.
The distance Dx between the holders in the width direction WDx orthogonal to the transport direction MD at a certain point of the transported stretched film 1 is the intersection point Px1 between the width direction WDx and the locus 3R, and the intersection point Px1 between the width direction WDx and the locus 3L. It is the distance from the intersection point Px2. Hereinafter, the distance between the holders in the width direction of the stretched film may be indicated as the distance Dx. The distance Dx usually corresponds to the distance between the ends of the transported stretched film.

The distance Dx is constant while step (A) is performed. The fact that the distance Dx is constant includes the case where the distance Dx fluctuates within a range that does not impair the effects of the present invention. The distance Dx may vary, for example, within a range of ±1% or less, ±0.5% or less, or ±0.3% or less of the average value.

The stretched film is treated at temperature T1 while maintaining the conditions described above. Here, the temperature T1 satisfies the following formula (1).
Tg≦T1≦Tm (1)
Here, Tg represents the glass transition temperature of the crystalline polymer contained in the thermoplastic resin forming the stretched film, and Tm represents the melting point of the polymer.
As long as the formula (1) is satisfied, the temperature T1 may be constant, may be changed stepwise, or may be changed continuously. Preferably, temperature T1 is constant.

The method of treating the stretched film at the temperature T1 is not particularly limited, but the stretched film is usually heated. As a device for heating, a heating device capable of raising the ambient temperature of the stretched film is preferable because contact between the heating device and the original film is unnecessary. Specific examples of suitable heating devices include ovens and furnaces. The temperature of the stretched film usually corresponds to the ambient temperature of the stretched film.

In step (A), the time for treating the stretched film at temperature T1 is preferably 1 second or longer, more preferably 5 seconds or longer, particularly preferably 20 seconds or longer, preferably 10 minutes or shorter, and more preferably It is preferably 5 minutes or less, particularly preferably 1 minute or less. By setting the treatment time to the above lower limit or more, the crystallization of the crystalline polymer can be sufficiently advanced, and the heat resistance of the resin film can be enhanced. Further, by making the content equal to or less than the above upper limit, clouding of the resin film can be suppressed, so that a resin film suitable for use as an optical film can be obtained.

[1.3. Step (C)]
Step (C) is performed after step (A). In the step (C), the stretched film is cooled at a temperature T3 while two longitudinal sides of the stretched film are held by a holder. As a result, a resin film having excellent flatness and good edge properties after trimming can be obtained.

In step (C), as the holder for holding the stretched film, the same holder as used in step (A) can be used.
In step (C), the distance between the holders in the width direction of the stretched film (distance Dx) may be constant, or may be reduced as the stretched film is conveyed downstream. Preferably, step (C) is performed while reducing the distance Dx.

The temperature T3 usually satisfies the following formulas (2) and (3).
T3≤Tg (2)
T3<T1 (3)
Here, Tg is the same as defined in formula (1), and T1 is the treatment temperature in step (A).

As long as the formulas (2) and (3) are satisfied, the temperature T3 may be constant, change stepwise, or change continuously. Preferably, temperature T3 is constant.
The temperature T3 is usually the ambient temperature of the stretched film. The temperature of the stretched film usually corresponds to the ambient temperature.

A method for cooling the stretched film at temperature T3 is not particularly limited. As a device for cooling at the temperature T3, a heating device or a cooling device can be used depending on the temperature T3.
Examples and preferred examples of the heating device include devices similar to the heating device that can be used in step (A).
Examples of the cooling device include a blower, a device having a circulation mechanism for coolant, and the like.

The temperature T3 is preferably (Tg-60) (°C) or higher, more preferably (Tg-50) (°C) or higher, and usually Tg (°C) or lower, more preferably (Tg-10) (°C) or lower. is.

In step (C), the time for treating the stretched film at temperature T3 is preferably 1 second or longer, more preferably 5 seconds or longer, particularly preferably 10 seconds or longer, preferably 10 minutes or shorter, and more preferably It is preferably 5 minutes or less, particularly preferably 1 minute or less.
By setting the treatment time to the above lower limit or more, the crystallization of the crystalline polymer can be sufficiently progressed, the heat resistance of the resin film can be improved, the flatness is excellent, and the edge part after trimming can be improved. A resin film having better properties can be produced. Further, by making the content equal to or less than the above upper limit, clouding of the resin film can be suppressed, so that a resin film suitable for use as an optical film can be obtained.

[1.4. Step (B)]
As described above, the method for producing a resin film according to one embodiment of the present invention may further include step (B) after step (A) and before step (C).
In the step (B), two sides of the stretched film in the longitudinal direction are held by a holder, and the stretched film is treated at temperature T2.

The temperature T2 usually satisfies the following formulas (4) and (5).
Tg≦T2≦Tm (4)
T3<T2<T1 (5)
Here, Tg and Tm are the same as defined in formula (1), T1 is the treatment temperature in step (A), and T3 is the treatment temperature in step (C).

As long as the formulas (4) and (5) are satisfied, the temperature T2 may be constant, change stepwise, or change continuously.
The temperature T2 is usually the ambient temperature of the stretched film.

In step (B), as the holder for holding the stretched film, the same holder as used in step (A) can be used.
In step (B), the distance between the holders in the width direction of the stretched film (distance Dx) may be constant, or may be reduced as the stretched film is conveyed downstream. Preferably, step (B) is performed while reducing the distance Dx. Thereby, when the resin film is left at a high temperature for a long time (for example, at 145° C. for 1 hour), the thermal dimensional change rate (thermal dimensional change rate) of the resin film can be reduced.

When the steps (C) and (B) are performed while reducing the distance Dx, the reduction ratio Xc of the distance Dx in the step (C) and the reduction ratio Xb of the distance Dx in the step (B) are obtained by the following formula (6 ) is preferably satisfied.
Xb<Xc (6)

Here, the reduction rate Xy (%) of the distance Dx in a certain process Y is represented by the following formula (9).
Xy (%) = (Dy0-Dy1)/Dy0 x 100 (9)
In the above formula, Dy0 represents the distance between the holders in the width direction of the stretched film at the start of step Y, and Dy1 represents the distance between the holders in the width direction of the stretched film at the end of step Y. show. The reduction ratio Xc in step (C) and the reduction ratio Xb in step (B) can also be calculated by the above equation (9).
The reduction ratio Xc in step (C) is preferably 1% or more and preferably 10% or less as long as the formula (6) is satisfied.
The reduction ratio Xb in step (B) is preferably 0.1% or more, preferably 10% or less, and more preferably less than 10%, as long as formula (6) is satisfied.

When the distance Dx in step (B) is reduced as the stretched film is conveyed downstream, the reduction rate of the distance Dx may be the same or varied during step (B). good. The reduction ratio may be changed stepwise or may be changed continuously.
Preferably, in step (B), the reduction rate of the distance Dx is increased stepwise or continuously as the stretched film is conveyed downstream.
More preferably, in step (B), the reduction ratio of the distance Dx is increased stepwise or continuously as the stretched film is conveyed downstream, and the treatment temperature T2 is lowered stepwise or continuously. . Thereby, it is possible to manufacture a resin film having superior flatness and having superior edge properties after trimming.
More preferably, step (B) includes step (B1) and step (B2) in this order.

(Step (B1) and Step (B2))
In step (B1), the stretched film is treated at temperature T21 while reducing the distance Dx between the holders in the width direction of the stretched film.
In step (B2), the stretched film is treated at temperature T22 while reducing the distance Dx between the holders in the width direction of the stretched film.

Here, temperature T21 and temperature T22 satisfy equation (7).
Tg≦T22<T21<T1 (7)
In the above formula, T1 and Tg are the same as defined in formula (1).
Thereby, it is possible to manufacture a resin film having superior flatness and having superior edge properties after trimming.

Further, the reduction ratio Xb1 of the distance Dx in step (B1) and the reduction ratio Xb2 of the distance Dx in step (B2) satisfy the following formula (8).
Xb1<Xb2 (8)
The reduction ratio Xb1 in the step (B1) is preferably 0.2% or more and preferably 5% or less as long as the formula (8) is satisfied.
The reduction ratio Xb2 in step (B2) is preferably 0.4% or more, preferably 10% or less, and more preferably less than 10%, as long as formula (8) is satisfied.

The reduction ratio Xb1 in step (B1) and the reduction ratio Xb2 in step (B2) can be calculated according to equation (9).

The reduction ratio Xc, the reduction ratio Xb1, and the reduction ratio Xb2 preferably satisfy the following formula (10).
Xb1<Xb2<Xc (10)
Thereby, it is possible to manufacture a resin film having superior flatness and having superior edge properties after trimming.

In step (B1), the time for treating the stretched film at temperature T21 is preferably 1 second or longer, more preferably 5 seconds or longer, particularly preferably 20 seconds or longer, preferably 10 minutes or shorter, and more preferably It is preferably 5 minutes or less, particularly preferably 2 minutes or less.
In step (B2), the time for treating the stretched film at temperature T22 is preferably 1 second or longer, more preferably 5 seconds or longer, particularly preferably 10 seconds or longer, preferably 10 minutes or shorter, and more preferably It is preferably 5 minutes or less, particularly preferably 1 minute or less.
By setting the treatment time to the above lower limit or more, the crystallization of the crystalline polymer can be sufficiently progressed, the heat resistance of the resin film can be improved, the flatness is excellent, and the edge part after trimming can be improved. A resin film having better properties can be produced. Further, by making the content equal to or less than the above upper limit, clouding of the resin film can be suppressed, so that a resin film suitable for use as an optical film can be obtained.

[1.5. optional process]
The method for producing a resin film of the present embodiment may further include an optional step in addition to the step (A), step (C), and optional step (B).
Examples of optional steps include a step of stretching the original film to obtain a stretched film, a step of surface-treating the resin film, and a step of trimming the width direction end portions of the resin film.

[2. embodiment]
The method for producing the resin film can be carried out using a production apparatus equipped with an oven and capable of changing the distance Dx between the holders in the width direction of the stretched film. Examples of the manufacturing apparatus include a horizontal uniaxial stretching apparatus equipped with a mechanism capable of changing the distance Dx. An example of a resin film manufacturing apparatus will be described below.

FIG. 2 is a schematic diagram schematically showing the upper surface of a manufacturing apparatus that can be used in the resin film manufacturing method.
As shown in FIG. 2, the manufacturing apparatus 100 includes an oven 30 and a conveying device 200. As shown in FIG.
The manufacturing apparatus 100 stretches the original film 20 unwound from the roll 10 in the width direction perpendicular to the film transport direction MD1 under the heating environment of the oven 30 to form a stretched film 40, and then processes (A) to (C) is performed.

The manufacturing apparatus 100 includes a plurality of grippers 110R and 110L and a pair of guide rails 120R and 120L. The grippers 110R and 110L are provided so as to grip the ends 21 and 22 of the raw film 20 in the width direction, respectively. Guide rails 120R and 120L are provided on both sides of the film transport path to guide the grippers 110R and 110L. The gripper 110R and the gripper 110L function as holders for holding the film.

The grippers 110R and 110L are provided so as to be able to travel along the guide rails 120R and 120L. Further, the grippers 110R and 110L are provided so as to keep a constant distance from the front and rear grippers 110R and 110L, respectively, and to travel at a constant speed. Further, the grippers 110R and 110L respectively grip and convey the widthwise end portions 21 and 22 of the raw film 20 sequentially supplied to the manufacturing apparatus 100 at the entrance portion 130 of the manufacturing apparatus 100, thereby manufacturing It has a configuration that allows the resin film 50 thus formed to be released at the exit portion 140 of the manufacturing apparatus 100 . The released resin film 50 is wound up by a winding device (not shown) and collected as a roll 60 .

Further, the guide rails 120R and 120L have endless continuous tracks so that the grippers 110R and 110L can circulate on predetermined tracks. For this reason, the manufacturing apparatus 100 has a configuration in which the grippers 110R and 110L, which have released the resin film 50 at the exit portion 140 of the manufacturing apparatus 100, can be returned to the entrance portion 130 in sequence.

The guide rails 120R and 120L are provided with an extension zone 150 in which the distance between the guide rails 120R and 120L increases toward the downstream side.
Further, the guide rails 120R and 120L are provided with a first heat treatment zone 160 in which the distance between the guide rails 120R and 120L is constant.
Further, the guide rails 120R and 120L are provided with a second heat treatment zone 170, a third heat treatment zone 180, and a cooling zone 190 in which the distance between the guide rails 120R and 120L becomes smaller toward the downstream. The drawing zone 150, first heat treatment zone 160, second heat treatment zone 170, third heat treatment zone 180, and cooling zone 190 are contiguous.

The distance Da0 is the distance between the grippers 110R and 110L at the most upstream point in the first heat treatment zone 160, and the distance Da1 is the distance between the grippers 110R and 110L at the most downstream point in the first heat treatment zone 160. is the distance of
The distance between the guide rails 120R and 120L in the first heat treatment zone 160 is adjusted so that the distance Da0 and the distance Da1 are the same.

The distance Db10 is the distance between the grippers 110R and 110L at the most upstream point of the second heat treatment zone 170, and the distance Db11 is the distance between the grippers 110R and 110L at the most downstream point of the second heat treatment zone 170. is the distance of
The interval between the guide rails 120R and 120L in the second heat treatment zone 170 is adjusted such that the distance Db11 is smaller than the distance Db10.

Distance Db20 is the distance between gripper 110R and gripper 110L at the most upstream point of third heat treatment zone 180, and distance Db21 is the distance between gripper 110R and gripper 110L at the most downstream point of third heat treatment zone 180. is the distance of
The distance between the guide rails 120R and 120L in the third heat treatment zone 180 is adjusted such that the distance Db21 is smaller than the distance Db20.

Distance Dc0 is the distance between gripper 110R and gripper 110L at the most upstream point of cooling zone 190, and distance Dc1 is the distance between gripper 110R and gripper 110L at the most downstream point of cooling zone 190. be.
The interval between the guide rails 120R and 120L in the cooling zone 190 is adjusted so that the distance Dc1 is smaller than the distance Dc0.

In the second heat treatment zone 170, the third heat treatment zone 180, and the cooling zone 190, the distance between the guide rails 120R and 120L is further adjusted so that X2 to X4 satisfy the following relationship.
0<X2<X3<X4
Here, X2 means the reduction ratio calculated from the distance Db10 and the distance Db11 according to the formula (9) in the second heat treatment zone 170,
X3 means the reduction ratio calculated from the distance Db20 and the distance Db21 according to the formula (9) in the third heat treatment zone 180,
X4 means a contraction ratio in the cooling zone 190 calculated from the distance Dc0 and the distance Dc1 according to Equation (9).

The oven 30 is installed so as to surround the transport path of the film, and inside it surrounds the stretching zone heating section 31 surrounding the stretching zone 150, the first heating section 32 surrounding the first heat treatment zone 160, and the second heat treatment zone 170. It is divided into the second heating section 33 , the third heating section 34 surrounding the third heat treatment zone 180 , and the cooling section 35 surrounding the cooling zone 190 .

The first heating section 32, the second heating section 33, the third heating section 34, and the cooling section 35 are temperature-set so that their internal temperatures are T1, T21, T22, and T3, respectively.
T1, T21, T22, and T3 are the same as defined above, and are temperatures that satisfy the following formulas (1) to (3) and (7).
Tg≦T1≦Tm (1)
T3≤Tg (2)
T3<T1 (3)
Tg≦T22<T21<T1 (7)

The manufacturing of the resin film 50 using the manufacturing apparatus 100 is performed as follows.
A raw film 20 is unwound from a roll 10 and continuously supplied to a manufacturing apparatus 100 .
The manufacturing apparatus 100 sequentially grips the ends 21 and 22 in the width direction of the raw film 20 at the inlet 130 with the grippers 110R and 110L. The raw film 20 with the ends 21 and 22 gripped is transported as the grippers 110R and 110L travel.

As described above, the gap between the guide rails 120R and 120L along which the grippers 110R and 110L travel is arranged such that the gap increases toward the downstream side in the stretching zone 150 . Therefore, the raw film 20 gripped by the grippers 110R and 110L is stretched in the width direction of the raw film 20 in the stretching zone 150 to obtain a long stretched film 40. FIG.

Further, as described above, the distance between the guide rails 120R and 120L on which the grippers 110R and 110L travel and the temperature of the oven 30 are adjusted. Therefore, the step (A) is performed in the first heat treatment zone 160, the step (B1) is performed in the second heat treatment zone 170, the step (B2) is performed in the third heat treatment zone 180, and the cooling zone 190 , the step (C) can be performed.

The obtained resin film 50 is released from the grippers 110R and 110L at the exit portion 140 of the manufacturing apparatus 100, wound up, and collected as a roll 60. As shown in FIG.

EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples. However, the present invention is not limited to the examples shown below, and can be arbitrarily modified without departing from the scope of the claims of the present invention and their equivalents.

In the following description, "%" and "parts" representing amounts are by weight unless otherwise specified. In addition, unless otherwise specified, the operations described below were performed under normal temperature and pressure conditions.

[Evaluation method]
(Measurement method of glass transition temperature Tg and melting point Tm)
A sample heated to 300° C. in a nitrogen atmosphere was quenched with liquid nitrogen and heated at a rate of 10° C./min using a differential scanning calorimeter (DSC) to determine the glass transition temperature Tg and melting point Tm of the sample. .

(Method for measuring hydrogenation rate of polymer)
The hydrogenation rate of the polymer was measured by ¹ H-NMR measurement at 145° C. using ortho-dichlorobenzene-d ⁴ as a solvent.

(Method for Measuring Ratio of Racemo Diad in Polymer)
¹³ C-NMR measurement of the polymer was performed using ortho-dichlorobenzene-d ⁴ as a solvent at 200° C. and applying the inverse-gated decoupling method. From the results of this ¹³ C-NMR measurement, a 43.35 ppm signal derived from the meso dyad and a 43.43 ppm signal derived from the racemo dyad, with the 127.5 ppm peak of ortho-dichlorobenzene-d ⁴ as the standard shift. identified. Based on the intensity ratio of these signals, the proportion of racemo dyads in the polymer was determined.

(Method for measuring thermal dimensional change rate of film)
Under the environment of room temperature 23° C., the film was cut into a square having a size of 150 mm×150 mm to obtain a sample film. Each side of the square was arranged along the transport direction or width direction of the film. The sample film was heated in an oven at 145° C. for 1 hour and cooled to 23° C. (room temperature), after which the lengths of the four sides of the sample film were measured.

Based on the measured lengths of the four sides, the thermal dimensional change rate of the sample film was calculated according to the following formula (I). In formula (I), _LA represents the side length of the sample film after heating.
Thermal dimensional change rate (%) = [(L _A -150)/150] x 100 (I)

Then, among the calculated values of the thermal dimensional change rates of the two sides along the transport direction of the film, the value with the maximum absolute value was employed as the thermal dimensional change rate in the transport direction (MD) of the film. Also, among the calculated values of the thermal dimensional change rate of the two sides along the width direction of the film, the value with the maximum absolute value was adopted as the thermal dimensional change rate of the film in the width direction (TD).

(Film flatness)
The produced resin film was visually observed, and the flatness was evaluated based on the presence or absence of unevenness of the resin film. Evaluation criteria are as follows.
A: Unevenness is not observed.
B: Unevenness is slightly observed.
C: Concavities and convexities are observed over the entire film.

(State of resin film edge after trimming)
Both ends of the obtained resin film were trimmed with a cutter, and the state of the trimmed ends of the resin film was visually observed and evaluated. Evaluation criteria are as follows.
A: No cracks or undulations at the edge. In addition, fine thread-like waste (fluff) is not adhered to the ends.
B: There are no cracks or fluffs at the edges, but there is slight waviness.
C: Cracks, significant waviness, and/or fluff are generated at the edge.

[Production Example 1]
(1-1. Preparation of resin pellets)
After sufficiently drying the metal pressure-resistant reactor, the atmosphere was replaced with nitrogen. In this metal pressure-resistant reactor, 154.5 parts of cyclohexane, 42.8 parts of a 70% cyclohexane solution of dicyclopentadiene (the content of endo bodies is 99% or more) (30 parts as the amount of dicyclopentadiene), and 1- Add 1.9 parts of hexene and heat to 53°C.

To a solution of 0.014 parts of tetrachlorotungstenphenylimide (tetrahydrofuran) complex dissolved in 0.70 parts of toluene, 0.061 parts of a 19% diethylaluminum ethoxide/n-hexane solution was added and stirred for 10 minutes. to prepare a catalyst solution.
This catalyst solution was added to the pressure reactor to initiate the ring-opening polymerization reaction. Thereafter, the mixture was allowed to react for 4 hours while maintaining the temperature at 53° C. to obtain a solution of a ring-opening polymer of dicyclopentadiene.
The obtained ring-opening polymer of dicyclopentadiene had a number average molecular weight (Mn) and a weight average molecular weight (Mw) of 8,750 and 28,100, respectively. was 3.21.

0.037 parts of 1,2-ethanediol was added as a terminator to 200 parts of the obtained solution of the ring-opening polymer of dicyclopentadiene, heated to 60° C., and stirred for 1 hour to terminate the polymerization reaction. let me 1 part of a hydrotalcite-like compound (“Kyoward (registered trademark) 2000” manufactured by Kyowa Chemical Industry Co., Ltd.) was added thereto, heated to 60° C., and stirred for 1 hour. After that, 0.4 parts of a filter aid (“Radiolite (registered trademark) #1500” manufactured by Showa Chemical Industry Co., Ltd.) was added, and a PP pleated cartridge filter (“TCP-HX” manufactured by ADVANTEC Toyo Co., Ltd.) was used as an adsorbent. The solution was filtered off.

To 200 parts of the solution of the ring-opening polymer of dicyclopentadiene after filtration (polymer amount: 30 parts), 100 parts of cyclohexane was added, 0.0043 parts of chlorohydridocarbonyltris(triphenylphosphine)ruthenium was added, and hydrogen was added. A hydrogenation reaction was carried out at a pressure of 6 MPa and 180° C. for 4 hours. As a result, a reaction liquid containing the hydrogenated product of the ring-opening polymer of dicyclopentadiene was obtained. This reaction solution was a slurry solution with precipitation of the hydrogenated product.

The hydrogenated product and the solution contained in the reaction solution are separated using a centrifugal separator and dried under reduced pressure at 60° C. for 24 hours to obtain a hydrogenated product of a crystalline ring-opening polymer of dicyclopentadiene. 28.5 parts were obtained. This hydrogenated product had a hydrogenation rate of 99% or more, a glass transition temperature Tg of 93°C, a melting point (Tm) of 262°C, and a ratio of racemo dyads of 89%.

An antioxidant (tetrakis[methylene-3-(3',5'-di-t-butyl-4'-hydroxyphenyl)propionate) was added to 100 parts of the hydrogenated product of the resulting ring-opening polymer of dicyclopentadiene. 1.1 parts of methane; “Irganox (registered trademark) 1010” manufactured by BASF Japan Ltd.) was mixed to obtain a resin as a film material.

The above resin was put into a twin-screw extruder (“TEM-37B” manufactured by Toshiba Machine Co., Ltd.) equipped with four die holes with an inner diameter of 3 mmΦ. Using the twin-screw extruder, the resin was molded into a strand-like molding by hot-melt extrusion molding. This compact was cut into small pieces with a strand cutter to obtain resin pellets. The operating conditions of the twin-screw extruder are shown below.
・Barrel setting temperature: 270°C to 280°C
・Die setting temperature: 250°C
・Screw rotation speed: 145 rpm
・Feeder rotation speed: 50 rpm

(1-2. Production of raw film)
The resulting pellets were subsequently fed to a hot-melt extrusion film former equipped with a T-die. Using this film forming machine, a long raw film (width 500 mm) made of the above resin was produced by winding it around a roll at a predetermined roll speed. The roll speed was adjusted so that the raw film had a thickness of 30 μm.
The operating conditions of the film forming machine are shown below.
・Barrel temperature setting: 280°C to 290°C
・Die temperature: 270°C
・Screw rotation speed: 30 rpm

[Production Example 2]
A crystalline polyethylene terephthalate (PET) resin film (“Lumirror T60” manufactured by Toray Industries, Inc., thickness 100 μm, glass transition temperature Tg: 76° C., melting point 263° C.) was prepared.
Using the resin obtained by finely pulverizing the PET resin film with a pulverizer, in the same manner as in Production Example 1 (1-2. Production of raw film), a long raw film made of PET resin A film (500 mm wide) was obtained. The roll speed was adjusted so that the raw film had a thickness of 100 μm.

[Example 1]
A resin film was obtained by processing the raw film obtained in Production Example 1 using the production apparatus 100 shown in FIG.
Here, the temperature of each zone of the manufacturing apparatus 100 was set as follows so that the glass transition temperature of the resin Tg≦T22<T21<T1.
Temperature of drawing zone heating unit 31: Tg + 35°C
Temperature of first heating unit 32 (T1): Tg+75°C
Temperature of second heating unit 33 (T21): Tg+65°C
Temperature of third heating unit 34 (T22): Tg+30°C
Temperature of cooling part 35 (T3): Tg-45°C

In the stretching zone 150, the distance between the guide rails 120R and 120L was adjusted so that the lateral stretching ratio was 1.5 times.

Also, in each zone, the interval between the guide rails 120R and 120L was adjusted so that the reduction ratio satisfies the following relationship.
0<0.5%<X2<X3<X4<5%

The thermal dimensional change rate and flatness of the obtained resin film were evaluated by the methods described above. Furthermore, after trimming both ends in the longitudinal direction of the obtained resin film by the above method, the properties of both ends were evaluated.

[Example 2]
A resin film was obtained in the same manner as in Example 1, except that the following items were changed.
- In the second heat treatment zone 170 and the third heat treatment zone 180, the distance between the guide rails 120R and 120L is adjusted so that the reduction rate satisfies the following relationship.
X2=X3=0, 0.1%<X4<2%
The obtained resin film was evaluated in the same manner as in Example 1.

[Example 3]
A resin film was obtained in the same manner as in Example 1, except that the following items were changed.
- Instead of the raw film obtained in Production Example 1, the raw film obtained in Production Example 2 was used.
- The temperature of each zone of the manufacturing apparatus 100 was set as follows so that the resin glass transition temperature Tg≦T22<T21<T1.
Temperature of drawing zone heating unit 31: Tg + 25°C
Temperature (T1) of first heating unit 32: Tg+110°C
Temperature of second heating unit 33 (T21): Tg+95°C
Temperature of third heating unit 34 (T22): Tg+40°C
Temperature of cooling part 35 (T3): Tg-25°C
The obtained resin film was evaluated in the same manner as in Example 1.

[Comparative Example 1]
A resin film was obtained in the same manner as in Example 1, except that the following items were changed.
- Instead of the manufacturing apparatus 100, a manufacturing apparatus in which the cooling zone 190 is not provided in the manufacturing apparatus 100 and the outlet part 140 is directly connected to the third heat treatment zone 180 was used. In this manufacturing apparatus, the stretched film 40 that has passed through the third heat treatment zone 180 is immediately released from the grippers 110R and 110L without passing through the cooling zone.
The obtained resin film was evaluated in the same manner as in Example 1.

[Comparative Example 2]
A resin film was obtained in the same manner as in Example 2, except that the following items were changed.
- Instead of the manufacturing apparatus 100, a manufacturing apparatus in which the cooling zone 190 is not provided in the manufacturing apparatus 100 and the outlet part 140 is directly connected to the third heat treatment zone 180 was used. In this manufacturing apparatus, the stretched film 40 that has passed through the third heat treatment zone 180 is immediately released from the grippers 110R and 110L without passing through the cooling zone.
The obtained resin film was evaluated in the same manner as in Example 1.

[Comparative Example 3]
A resin film was obtained in the same manner as in Example 3, except that the following items were changed.
- Instead of the manufacturing apparatus 100, a manufacturing apparatus in which the cooling zone 190 is not provided in the manufacturing apparatus 100 and the outlet part 140 is directly connected to the third heat treatment zone 180 was used. In this manufacturing apparatus, the stretched film 40 that has passed through the third heat treatment zone 180 is immediately released from the grippers 110R and 110L without passing through the cooling zone.
The obtained resin film was evaluated in the same manner as in Example 1.

[result]
The above results are shown in the table below.
In the table below, abbreviations have the following meanings.
COP: Original fabric film formed from a hydrogenated product of ring-opening polymer of dicyclopentadiene PET: Original fabric film formed from PET X2: Reduction ratio of second heat treatment zone 170 X3: Reduction of third heat treatment zone 180 Edge of film: State of edge of resin film after trimming

From the above results, the following matters are known.
The resin films according to Examples 1 to 3 manufactured by the manufacturing apparatus having the cooling zone have good flatness and good film end properties. On the other hand, the resin films according to Comparative Examples 1 to 3 manufactured by the manufacturing apparatus having no cooling zone have poor flatness and film end properties. That is, according to the manufacturing method including the step (C) of cooling the stretched film at the temperature T3 while holding it with a holder, a resin film having excellent flatness and properties of the film edges can be obtained.
Further, the value of the thermal dimensional change rate of Example 1 relative to Comparative Example 1, the value of the thermal dimensional change rate of Example 2 relative to Comparative Example 2, and the value of the thermal dimensional change rate of Example 1 relative to Comparative Example 3 are all small. That is, by including the step (C) in the manufacturing method, it is possible to obtain a resin film with a smaller thermal dimensional change rate than in a manufacturing method that does not include the step (C).

Furthermore, the resin film according to Example 1 has a smaller thermal dimensional change rate than the resin film according to Example 2. The resin film according to Example 1 is produced by a manufacturing apparatus provided with a second heat treatment zone and a third heat treatment zone in which the reduction rate of the distance between the holders is 0 or more between the cooling zone and the first heat treatment zone. Manufactured by On the other hand, the resin film according to Example 2 is manufactured by a manufacturing apparatus provided with a second heat treatment zone and a third heat treatment zone in which the reduction ratio of the distance between the holders is zero.
That is, by performing step (B) while reducing the distance between the holders in the width direction of the stretched film, a resin film with a small thermal dimensional change rate can be obtained.
Further, by including the step (B1) and the step (B2) in the step (B), a resin film having a small thermal dimensional change rate can be obtained.

1: Stretched film 2R: First holder 2L: Second holder 3R: Trajectory 3L: Trajectory 10: Roll 20: Raw film 21: Edge 30: Oven 31: Stretching zone heating section 32: First heating Part 33: Second heating part 34: Third heating part 35: Cooling part 40: Stretched film 50: Resin film 60: Roll 100: Manufacturing device 110L: Gripper (holding tool)
110R: gripper (holding tool)
120L: Guide rail 120R: Guide rail 130: Entrance section 140: Exit section 150: Stretching zone 160: First heat treatment zone 170: Second heat treatment zone 180: Third heat treatment zone 190: Cooling zone 200: Conveying device MD: Conveying direction MD1: Conveying direction

Claims (3)

A long stretched film made of a thermoplastic resin containing a crystalline polymer is held in a tensioned state by holding two sides in the longitudinal direction of the stretched film with a holder. A step (A) of processing at temperature T1 while keeping the distance between the holders constant;
A step (C) of cooling the stretched film at a temperature T3 while holding two sides in the longitudinal direction of the stretched film with the holding fixture,
After the step (A) and before the step (C), a step (B) of holding two sides in the longitudinal direction of the stretched film by the holder and treating the stretched film at a temperature T2. further comprising
The cooling in the step (C) is performed while reducing the distance between the holders in the width direction of the stretched film,
performing the step (B) while reducing the distance between the holders in the width direction of the stretched film;
The step (B) is
A step (B1) of treating the stretched film at a temperature T21 while reducing the distance between the holders in the width direction of the stretched film, and then
A step (B2) of processing the stretched film at a temperature T22 while reducing the distance between the holders in the width direction of the stretched film,
Temperature T1 , temperature T2, temperature T3 , temperature T21 and temperature T22 satisfy the following equations,
A method for producing a resin film, wherein a reduction ratio Xb1 of the distance between the holders in the step (B1) and a reduction ratio Xb2 of the distance between the holders in the step (B2) satisfy the following formula.
Tg≦T1≦Tm (1)
T3≤Tg (2)
T3<T1 (3)
Tg≦T2≦Tm (4)
T3<T2<T1 (5)
Tg≦T22<T21<T1 (7)
Xb1<Xb2 (8)
Here, Tg represents the glass transition temperature of the crystalline polymer, and Tm represents the melting point of the crystalline polymer. The resin film according to claim 1 , wherein the reduction ratio Xb of the distance between the holders in the step (B) and the reduction ratio Xc of the distance between the holders in the step (C) satisfy the following formula. manufacturing method.
Xb<Xc (6) 3. The method for producing a resin film according to claim 1, wherein the crystalline polymer contained in the thermoplastic resin is an alicyclic structure-containing polymer.

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