JP2022010792A - Resin film and manufacturing method thereof - Google Patents

Abstract

To provide a long-sized crystalline resin film having small heat shrinkage rate in a longitudinal direction, and its manufacturing method.SOLUTION: A manufacturing method of a resin film characterized in that a resin film that is a long-sized resin film containing an alicyclic structure containing polymer with crystallinity, in which a braking elongation at a temperature of 150°C is 30% or smaller, and the heat shrinkage rate in the longitudinal direction at 145°C, 1 hour is 0.30% or smaller; as well as, its manufacturing method, in which an alicyclic structure-containing polymer with crystallinity is contained, and contains a step (1) for preparing a crystalline film having the breaking elongation at 150°C of 30% or smaller, and a step (2) for reducing the heat shrinkage by treating the crystalline film, the heat shrinkage reducing step (2) contains an elongation step (2-1) for extending the crystalline film.SELECTED DRAWING: None

Description

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

It is known that a resin containing an alicyclic structure-containing polymer is used as a resin film for various purposes. In particular, a film made of a material in which a crystalline resin is used as a resin containing an alicyclic structure-containing polymer and the crystallinity of the resin is increased by a process such as heating is to be used for various optical applications. (For example, Patent Document 1).

International Publication No. 2016/067893

When the heating step is performed to increase the crystallinity of the resin containing the alicyclic structure-containing polymer, the heat shrinkage rate of the obtained resin film may be undesirably increased. Such a resin film having a high heat shrinkage rate may cause an undesired phenomenon such as shrinkage over time when used as a component of an optical device such as a display device.

It is generally known that the film is subjected to a relaxation treatment in order to reduce the heat shrinkage rate. The relaxation treatment is usually carried out by holding the film in a state where shrinkage of the film is allowed to some extent and heating the film, and causing the shrinkage of the film to occur in a controlled manner. Such a process may be difficult to carry out depending on the shape of the film and the mode of production. For example, when a film is continuously manufactured as a long film, it is necessary to apply tension in the longitudinal direction of the film when transporting the film on a production line. It is relatively difficult to release this longitudinal tension in some parts of the production line, and in addition it is even more difficult to control the degree of film shrinkage due to such release. Therefore, it is particularly difficult to reduce the heat shrinkage in the longitudinal direction in a long film.

Therefore, an object of the present invention is to provide a long crystalline resin film having a small heat shrinkage in the longitudinal direction and a method for producing the same.

The present inventor has studied to solve the above problems. As a result, when a resin film containing an alicyclic structure-containing polymer is imparted with specific properties, such a reduction in heat shrinkage can be achieved, and by carrying out a specific step, the resin film can be obtained. The present invention has been completed by finding that such a property can be easily imparted.
That is, the present invention provides the following.

[1] A long resin film containing a crystalline alicyclic structure-containing polymer, having a breaking elongation at a temperature of 150 ° C. of 30% or less, and a longitudinal direction at 145 ° C. for 1 hour. A resin film having a heat shrinkage rate of 0.30% or less.
[2] The resin film according to [1], which has a crystallinity of 20% or more and 50% or less.
[3] The method for producing a resin film according to [1] or [2].
A preparation step (1) for preparing a crystallized film containing a crystalline alicyclic structure-containing polymer and having a breaking elongation at a temperature of 150 ° C. of 30% or less, and a heat shrinkability by treating the crystallized film. Including the heat shrinkage reduction step (2) to reduce
A method for producing a resin film, wherein the heat shrinkage reducing step (2) includes a stretching step (2-1) for stretching the crystallized film.
[4] The heat shrinkage reduction step (2) includes a relaxation step (2-2) in which the crystallized film is subjected to a relaxation treatment after the stretching step (2-1).
In the relaxation step (2-2), the crystallized film is held in a manner that allows the crystallized film to shrink in a direction parallel to the stretching direction in the stretching step (2-1). The method for producing a resin film according to [3], which comprises heating the crystallized film.
[5] The preparation step (1) is a step of preparing the raw fabric film (1-1), and the raw fabric film is heated, thereby increasing the crystallinity of the raw fabric film and the crystallization film. The method for producing a resin film according to [3] or [4], which comprises the crystallization step (1-2).
[6] The method for producing a resin film according to any one of [3] to [5], wherein the crystallinity of the crystallized film is 10% or more.
[7] The method for producing a resin film according to any one of [3] to [6], wherein the stretching direction in the stretching step (2-1) is the width direction of the crystallized film.

INDUSTRIAL APPLICABILITY According to the present invention, a long crystalline resin film having a small heat shrinkage in the longitudinal direction and a method for producing the same are provided.

Hereinafter, the present invention will be described in detail with reference to embodiments and examples. However, the present invention is not limited to the embodiments and examples shown below, and may be arbitrarily modified and implemented without departing from the scope of claims of the present invention and the equivalent scope thereof.

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

In the following description, the directions of the elements are "parallel" and "orthogonal", unless otherwise specified, within a range that does not impair the effect of the present invention, for example, within a range of ± 3 °, ± 2 °, or ± 1 °. It may include the error in.

In the following description, the width direction is a direction orthogonal to the longitudinal direction of the long film. Usually, the longitudinal direction of a long film coincides with the transport direction of the film.

[1. Resin film: Overview]
The resin film of the present invention is a long resin film containing a specific polymer, and has a specific elongation at break and a specific heat shrinkage rate. In the following, for convenience of explanation, the resin film of the present invention may be referred to as a "product film" in order to distinguish it from general resin films in general.

[1.1. Resin film material]
The product film contains a crystalline alicyclic structure-containing polymer. More specifically, the product film is a film formed of a thermoplastic resin containing a crystalline alicyclic structure-containing polymer.

The crystalline polymer means a polymer having a melting point Tm. It can be confirmed by using a differential scanning calorimeter (DSC) that the polymer has a melting point Tm.
The melting point of the crystalline polymer is not particularly limited, but is preferably 200 ° C. or higher, more preferably 230 ° C. or higher, and preferably 290 ° C. or lower.
The glass transition temperature of the crystalline polymer is not particularly limited, but is, for example, 70 ° C. or higher, 75 ° C. or higher, or 85 ° C. or higher, and for example, 170 ° C. or lower.

The alicyclic structure-containing polymer is a polymer having an alicyclic structure in the molecule and refers to a polymer obtained by a polymerization reaction using a cyclic olefin as a monomer or a hydrogenated product thereof. Further, as the alicyclic structure-containing polymer, one type may be used alone, or two or more types may be used in combination at any ratio.

Examples of the alicyclic structure-containing polymer having crystallinity include norbornene-based polymers. Examples of the alicyclic structure contained in the alicyclic structure-containing polymer include 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 the structural units having an alicyclic structure to all the structural units is preferably 30% by weight or more, more preferably 50% by weight or more, and particularly preferably 70% by weight or more. .. The heat resistance can be improved by increasing the ratio of the structural units having an alicyclic structure in the alicyclic structure-containing polymer as described above.
Further, in the alicyclic structure-containing polymer, the balance other than the structural unit having the alicyclic structure is not particularly limited and may be appropriately selected depending on 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 having crystallinity.
Polymer (β): A hydrogenated product of the polymer (α), which has crystallinity.
Polymer (γ): An addition polymer of a cyclic olefin monomer having crystallinity.
Polymer (δ): A hydrogenated product of the polymer (γ), which has crystallinity.

Specifically, the alicyclic structure-containing polymer is a ring-opening polymer of dicyclopentadiene having crystallinity, and a hydrogenated additive of the ring-opening polymer of dicyclopentadiene, which is crystalline. Those having properties are more preferable, and those hydrogenated by a ring-opening polymer of dicyclopentadiene and having crystallinity are particularly preferable. Here, in the open-ring polymer of dicyclopentadiene, the ratio of the structural unit derived from dicyclopentadiene to all the structural units is usually 50% by weight or more, preferably 70% by weight or more, more preferably 90% by weight or more. A polymer usually having a weight of 100% by weight or less, more preferably a polymer having a ratio of structural units derived from dicyclopentadiene to 100% by weight of all structural units.

The hydride of the ring-opening polymer of dicyclopentadiene preferably has a high proportion of racemic diad. Specifically, the proportion of racemic diad in the structural unit in the hydrogenated compound 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 racemic diads indicates a high syndiotactic stereoregularity. Therefore, the higher the proportion of racemic diad, the higher the melting point of the hydrogenated product of the ring-opening polymer of dicyclopentadiene.
The proportion of racemo diads can be determined based on the ¹³ C-NMR spectral analysis described in Examples described below.

In the thermoplastic resin forming the product film, the proportion of the polymer having crystallinity 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 proportion of the polymer having crystallinity to the lower limit of the above range or more, the heat resistance of the product film can be enhanced.

The thermoplastic resin forming the product film may contain any component in addition to the crystalline polymer.

[1.2. Breaking elongation]
The product film has a breaking elongation at a temperature of 150 ° C. of 30% or less. Specifically, the product film has a breaking elongation at a temperature of 150 ° C. of 30% or less in one or more of the in-plane directions. More specifically, when the product film is manufactured by a manufacturing method including a stretching step described later, it is preferable that the elongation at break in the direction in which the stretching step is performed is within the range. Further, it is preferable that the elongation at break in the width direction of the product film is within the range.

The elongation at break at a temperature of 150 ° C. of the product film is preferably 25% or less, more preferably 20% or less. In the present application, the elongation at break can be measured according to JIS K7161 (2014). According to what the present inventor has found, when a long resin film containing an alicyclic structure-containing polymer has such a low elongation at break, the film is further treated to heat shrink in the longitudinal direction. The rate can be easily reduced. A product film having such a low elongation at break can be easily produced by the production method of the present invention. Details of the manufacturing method will be described later.

[1.3. Heat shrinkage rate]
The product film has a heat shrinkage rate in the longitudinal direction of 0.30% or less at 145 ° C. for 1 hour. The heat shrinkage rate is preferably 0.25% or less, more preferably 0.20% or less. In general, it is difficult to set the heat shrinkage rate in the longitudinal direction of a long resin film containing a crystalline polymer to such a low value, but according to the present invention, the heat shrinkage rate is set to such a low value. Such product films can be easily manufactured. The heat shrinkage rate in the longitudinal direction can be obtained at the same time as the heat shrinkage rate in the width direction by the measuring method carried out in the examples described later.

[1.4. Other features of resin film]
The dimensions of the product film can be adjusted as appropriate to suit the desired application. The length in the width direction of the product film can be preferably in the range of 300 mm or more and 2000 mm or less. The thickness of the product film can be in the range of 10 μm or more and 200 μm or less.

The crystallinity of the resin constituting the product film may be in an appropriate range so as to obtain desired physical properties. Specifically, the crystallinity can be in the range of 10% or more and 50% or less. The crystallinity can be measured by X-ray diffraction.

[2. Resin film manufacturing method]
The method for producing the resin film of the present invention is not particularly limited, but can be produced by a production method including the steps (1) to (2) described below. Hereinafter, this manufacturing method will be described as the manufacturing method of the present invention.
Step (1): A preparation step of preparing a specific crystallization film.
Step (2): A heat shrinkage reduction step of treating the crystallized film to reduce the heat shrinkage.

[2.1. Step (1): Preparation step of crystallized film]
In the step (1), a crystallized film containing a crystalline alicyclic structure-containing polymer and having a breaking elongation at a temperature of 150 ° C. of 30% or less is prepared.
As the material constituting the crystallized film, the thermoplastic resin containing the alicyclic structure-containing polymer having crystallinity mentioned as the material of the product film can be used.

The step (1) is a step of preparing the raw film (1-1) and a crystallization step (1-) of heating the raw film to increase the crystallinity of the raw film to form a crystallization film. The process may include 2). There is a possibility that the raw film preparation step (1-1) and the crystallization step (1-2) can be performed at the same time (that is, the resin may be molded as a molded product having a high degree of crystallization). The normal film forming step includes a step of heating and melting the thermoplastic resin to form the film, and since the resulting film has a low degree of crystallization, the steps (1-1) and (1-2) are sequentially performed. The manufacturing method to be carried out can be easily carried out.

The raw film preparation step (1-1) can be performed by molding the resin by an arbitrary molding method. Examples of the molding method include an injection molding method, an extrusion molding method, a press molding method, an inflation molding method, a blow molding method, a calendar molding method, a casting molding method, and a compression molding method. The extrusion molding method is preferable because the thickness can be easily controlled.

The crystallization step (1-2) can be carried out by a treatment of heating the raw fabric film while holding the raw fabric film in a manner that does not allow the raw fabric film to shrink. By performing such a treatment, the crystallinity of the raw film can be increased to obtain a crystallized film. Further, since the resin containing the alicyclic structure-containing polymer having crystalline property has a decrease in elongation at break by increasing the crystallinity, the requirement for elongation at break is required by increasing the crystallinity. A film satisfying the conditions can be easily obtained.

The crystallization step (1-2) can be performed using a stretching device for stretching a long film. Specifically, the stretching device grips both ends of the film in the width direction with a large number of clips, and guides and runs the clips by a pair of rails arranged along the transport path at both ends in the width direction of the film. It can be a device capable of stretching a film. By adjusting the arrangement of the rails and the mode of running the clip along the rails, the dimensions in the longitudinal direction and the width direction of the film can be changed. For example, by arranging the rails so that the distance between the pair of rails changes from upstream to downstream, the widthwise dimension of the film in the transport path can be changed. Also, if the clips carried along the rails have a pantograph-like base-mounted configuration, the longitudinal dimensions of the film can be varied. However, without such a configuration, the clips are mounted on a chain base and the spacing between multiple clips on each rail (ie, the spacing between a clip and adjacent clips upstream of it, and downstream thereof). The stretching device in which the clips are run in a state where the distance between the adjacent clips is not changed in the transport path and the clips are kept at equal intervals cannot freely control the change in the dimensions in the longitudinal direction, but the structure is simple. Enables easier manufacturing implementation. In the manufacturing method of the present invention, as in the example described below, the heat shrinkage rate in the longitudinal direction can be reduced only by stretching and relaxing treatment only in the film width direction, and thus an easy manufacturing process in that respect. Therefore, it can be said that it is a manufacturing method capable of obtaining an effect that was difficult to obtain in the past.

In the crystallization step (1-2), heating of the raw film can be achieved by adjusting the ambient temperature of the film during transportation of the film. In the production method of the present invention, the temperature can be adjusted in the crystallization step (1-2) and each of the other steps by transporting the film in an oven. The heating temperature and heating time in the crystallization step (1-2) can be adjusted to an appropriate range in which crystallization can be achieved. The heating temperature can be set based on the Tg of the resin constituting the raw film. Specifically, the heating temperature can be adjusted in the range of (Tg + 30) ° C. or higher (Tg + 100) ° C. or lower. The heating time can be adjusted in the range of 15 seconds or more and 3 minutes or less.

The heating operation in the crystallization step (1-2) can be performed while holding the raw film in a manner that does not allow the raw film to shrink. Specifically, in a stretching device, the film is gripped by a clip and the film is conveyed while maintaining the dimensions in the longitudinal direction and the width direction of the film unchanged, or the dimensions in a certain direction of the film are slightly expanded. Such an operation can be performed by transporting the film in a stretched state. When the film is stretched, it is preferable to stretch the film in the same direction as the stretching direction in the stretching step (2-1) (described later) in the heat shrinkage reducing treatment, and it is preferable to stretch the film in the width direction. According to what the present inventor has found, stretching in such a direction has an unexpected effect that the heat shrinkage rate in the longitudinal direction can be reduced. More specifically, the stretching in the crystallization step (1-2) is preferably 1.0 times or more and 1.5 times or less in the width direction, and more preferably 1.0 times or more and 1.3 times or less in the width direction. Is an extension of.

The heating operation in the crystallization step (1-2) can be an operation including a treatment at a relatively low treatment temperature (i) and a subsequent treatment at a relatively high treatment temperature (ii). In this case, when the raw film is stretched, it is preferable to stretch it only in the step (i). By performing the treatment (i) and the treatment (ii) in combination, the crystallized state of the crystallized film can be better expressed. The temperature difference between the temperature of the treatment (i) and the temperature of the treatment (ii) is preferably 5 ° C. or higher and 30 ° C. or lower, and more preferably 10 ° C. or higher and 25 ° C. or lower.

The elongation at break of the crystallized film obtained in the step (1) at a temperature of 150 ° C. can be 30% or less. However, since the breaking elongation of the final product film can be increased by going through the subsequent steps, it is preferable to adjust the breaking elongation at this point to a lower value. Specifically, the elongation at break is preferably 25% or less, more preferably 20% or less. Such a low elongation at break can be easily achieved by increasing the crystallinity.

The crystallinity of the crystallinity film obtained in the step (1) can be 10% or more, preferably 20% or more. By having such a high crystallinity, other physical properties such as elongation at break can be set to a desired value.

The crystallized film obtained in the step (1) may be immediately subjected to the step (2), but the crystallized film is once recovered as a film roll, and then the crystallized film is unwound from the film roll to perform the step ( It may be used for 2).

[2.2. Step (2): Heat shrinkage reduction treatment]
In the step (2), the crystallized film is heat-shrinkable reduced. The heat shrinkage reducing step (2) includes a stretching step (2-1) for stretching the crystallized film. The heat shrinkage reducing step (2) may further include a relaxation step (2-2) in which the crystallized film is subjected to a relaxation treatment after the stretching step (2-1).

The stretching direction in the stretching step (2-1) can be any direction in which the heat shrinkage in the longitudinal direction of the product film can be reduced, but usually, it can be in the width direction or an oblique direction close to the width direction. Specifically, the angle formed with the width direction of the film is preferably within 10 °, more preferably within 5 °, and even more preferably within 1 °. The stretching in the stretching step (2-1) may be stretching in two or more directions, but is typically uniaxial stretching in the width direction. According to what the present inventor has found, by stretching the crystallized film in this direction, it is possible to obtain an unexpected effect that the heat shrinkage rate in the longitudinal direction can be reduced.

The draw ratio in the stretching step (2-1) is preferably 1.01 times or more, more preferably 1.02 times or more, while preferably 1.10 times or less, more preferably 1.09 times or less. .. By stretching at such a magnification, it is possible to more effectively reduce the heat shrinkage rate in the longitudinal direction.

The temperature in the stretching step (2-1) can be adjusted to an appropriate range in which the effects of the present invention can be exhibited. The temperature at the time of stretching can be set based on the Tg of the resin constituting the raw film. Specifically, the temperature at the time of stretching can be adjusted in the range of (Tg + 60) ° C. or higher (Tg + 90) ° C. or lower.

The operation in the stretching step (2-1) may be an operation including a process of expanding the dimensions of the film (iii) and a subsequent process of holding the film while maintaining the expanded dimensions (iv). By performing the treatment (iii) and the treatment (iv) in combination, it is possible to more effectively reduce the heat shrinkage rate in the longitudinal direction. It is preferable that the temperature difference between the temperature of the treatment (iii) and the temperature of the treatment (iv) is small, and more specifically, setting the same temperature without providing a temperature difference is both effective and easy to treat. It is preferable from the viewpoint of. The processing times of processing (iii) and (iv) can be adjusted by appropriately adjusting the arrangement of the rails in the transport path and other conditions. The processing time of the processing (iii) can be adjusted in the range of 1 second or more and 10 seconds or less. The processing time of the processing (iv) can be adjusted in the range of 5 seconds or more and 30 seconds or less.

The film after the completion of the stretching step (2-1) may be used as it is as a product film, and may be further subjected to a relaxation step (2-2) and then used as a product film. By performing the relaxation step (2-2), it is possible to control not only the heat shrinkage rate in the longitudinal direction but also the heat shrinkage rate in the width direction to a low value such as 0.30% or less, which is particularly preferable.

The relaxation step (2-2) involves heating the film while holding the film. The holding of the film here is holding in a manner that allows the film to shrink in a direction parallel to the stretching direction in the stretching step (2-1). Such holding is an embodiment that allows the film to shrink in the width direction, for example, when the film is stretched in the width direction in the stretching step (2-1). Such holding can be performed, for example, by arranging the pair of rails of the stretching device described above so that the distance between the pair of rails is reduced from upstream to downstream. When such holding is performed, the film shrinks, but shrinkage at an arbitrary shrinkage ratio is not allowed, but shrinkage up to a certain shrinkage ratio is allowed, and shrinkage at a magnification higher than that is prevented. To. By performing such relaxation, the film is subjected to the shrinkage treatment in an embodiment in which the shrinkage ratio is limited. In this case, the shrinkage ratio is preferably 0.90 times or more, more preferably 0.91 times or more, while preferably 0.99 times or less, more preferably 0.98 times or less. Further, it is preferable to adjust these ratios so that the product of the draw ratio in the stretching step (2-1) and the shrinkage ratio in the relaxation step (2-2) is close to 1. Specifically, it is preferable that the value of the product is in the range of 0.97 or more and 1.03 or less.

The temperature in the relaxation step (2-2) can be set based on the Tg of the resin constituting the raw film. Specifically, the temperature in the relaxation step can be adjusted in the range of (Tg + 60) ° C. or higher and (Tg + 90) ° C. or lower. Further, it is preferable that the temperature difference between the temperature at the downstream end of the stretching step (2-1) and the temperature of the relaxation step (2-2) is small, and more specifically, the temperature should be the same without providing a temperature difference. Is preferable from the viewpoint of both effect manifestation and ease of processing.

The relaxation step (2-2) may be an operation including a process (v) of shrinking the size of the film and a subsequent process (vi) of holding the film while maintaining the shrunk size. By performing the treatment (v) and the treatment (vi) in combination, it is possible to more effectively reduce the heat shrinkage rate in the width direction. It is preferable that the temperature difference between the temperature of the treatment (v) and the temperature of the treatment (vi) is small, and more specifically, keeping the same temperature without providing a temperature difference is both effective and easy to treat. Preferred from the point of view. The processing times of processing (v) and (vi) can be adjusted by appropriately adjusting the arrangement of rails in the transport path and other conditions. The processing time of the processing (v) can be adjusted in the range of 1 second or more and 10 seconds or less. The processing time of the processing (vi) can be adjusted in the range of 5 seconds or more and 30 seconds or less.

The film obtained in the step (2) can be in a form suitable for winding, storing and transporting a film roll or the like as a product film.

[3. Use]
The application of the resin film of the present invention is not particularly limited, but it is a film of a component in an optical device such as a liquid crystal display device and an organic electroluminescence display device by utilizing the fact that it can be efficiently manufactured and has a small heat shrinkage rate. Can be used as.

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 may be arbitrarily modified and implemented without departing from the scope of claims of the present invention and the equivalent scope thereof.

In the following description, "%" and "part" representing quantities are based on weight unless otherwise specified. The operations described below were performed under normal temperature and pressure conditions unless otherwise specified.

〔Evaluation methods〕
(Elongation at break)
The breaking elongation of the film was measured by the following method according to JIS K7161 (2014). A test piece (IA) specified in JIS K7161 (2014) was cut out from the film to be measured (crystallized film, product film, etc.). When cutting out the test piece, the film was cut out so that the width direction of the film coincided with the longitudinal direction of the test piece.
At a test temperature of 150 ° C ± 1 ° C, the test piece was stretched with a tensile tester (“Tensile tester with constant temperature and humidity chamber” manufactured by Instron Japan), and the elongation amount ΔL when broken was measured to obtain the initial length. From L0 and ΔL, the breaking elongation was calculated by the breaking elongation (%) = ΔL / L0 × 100. Those that did not break even when ΔL = L0 were defined as more than 100%.

(Heat shrinkage rate)
The film was cut into squares having a size of 150 mm × 150 mm under an environment of room temperature of 23 ° C. to obtain a sample film. Each side of the square was aligned with the longitudinal or width direction of the film. This sample film was heated in an oven at 145 ° C. for 1 hour, cooled to 23 ° C. (room temperature), and then the lengths of the four sides of the sample film were measured.
Based on the measured lengths of each of the four sides, the rate of change in thermal dimensions of the sample film was calculated based on the following formula (I). In formula (I), LA indicates the length of the sides of the sample film after heating.
Heat shrinkage rate (%) = [(150-LA) / 150] x 100 (I)
Then, among the calculated values of the thermal dimensional change rates of the two sides along the longitudinal direction of the film, the value having the maximum absolute value was adopted as the thermal dimensional change rate in the longitudinal direction (MD) of the film. Further, among the calculated values of the thermal dimensional change rate of the two sides along the width direction of the film, the value having the maximum absolute value was adopted as the thermal dimensional change rate in the width direction (TD) of the film.

(Physical characteristics of polymer)
The hydrogenation rate of the polymer was measured by ¹ H-NMR measurement at 145 ° C. using orthodichlorobenzene ^- d4 as a solvent.
The proportion of racemic diads in the polymer was determined by ¹³ C-NMR measurement. ¹³ C-NMR measurement of the polymer was carried out by applying the inverted-gated decoupling method at 200 ° C. using ordichlorobenzene ^- d4 as a solvent. From the results of this ¹³ C-NMR measurement, a signal of 43.35 ppm derived from meso-diad and a signal of 43.43 ppm derived from racemic diad were used as a reference shift with the peak of 127.5 ppm of orthodichlorobenzene ^- d4 as a reference shift. Was identified. Based on the intensity ratios of these signals, the proportion of racemic diads in the polymer was determined.

(Crystallinity of crystallized film and product film)
The crystallinity of the crystallinity film and the product film was measured by the X-ray diffraction method according to JIS K0131 for the crystallinity of the polymer contained in. Specifically, a wide-angle X-ray diffractometer (RINT 2000, manufactured by Rigaku Co., Ltd.) was used to determine the diffraction X-ray intensity from the crystallized portion, and the following formula was obtained from the ratio with the overall diffraction X-ray intensity. The crystallinity was determined by (I).
Xc = K · Ic / It (I)
In the above formula (I), Xc represents the crystallinity of the test sample, Ic represents the diffraction X-ray intensity from the crystallized portion, It represents the entire diffraction X-ray intensity, and K represents the correction term.

[Manufacturing Example 1: Production of Resin]
The metal pressure-resistant reactor was sufficiently dried and then replaced with nitrogen. In this metal pressure resistant reactor, 154.5 parts of cyclohexane, 42.8 parts of a 70% cyclohexane solution of dicyclopentadiene (endo content of 99% or more) (30 parts as the amount of dicyclopentadiene), and 1- 1.9 parts of hexene was added and heated to 53 ° C.

0.014 parts of the tetrachlorotungsten phenylimide (tetrahydrofuran) complex was dissolved in 0.70 parts of toluene to prepare a solution. To this solution, 0.061 part of a diethylaluminum ethoxide / n-hexane solution having a concentration of 19% was added and stirred for 10 minutes to prepare a catalytic solution. This catalyst solution was added to the pressure resistant reactor to initiate the ring-opening polymerization reaction. Then, the reaction was carried out for 4 hours while maintaining 53 ° C. to obtain a solution of a ring-opening polymer of dicyclopentadiene. The number average molecular weight (Mn) and weight average molecular weight (Mw) of the obtained ring-opening polymer of dicyclopentadiene are 8,750 and 28,100, respectively, and the molecular weight distribution (Mw / Mn) obtained from these. Was 3.21.

To 200 parts of the obtained solution of the ring-opening polymer of dicyclopentadiene, 0.037 parts of 1,2-ethanediol was added as a terminator, heated to 60 ° C., and stirred for 1 hour to stop the polymerization reaction. I let you. A part of a hydrotalcite-like compound (“Kyoward (registered trademark) 2000” manufactured by Kyowa Chemical Industry Co., Ltd.) was added thereto, and the mixture was heated to 60 ° C. and stirred for 1 hour. After that, 0.4 part of a filtration 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 a solution of a ring-opening polymer of dicyclopentadiene after filtration (polymer amount: 30 parts), 100 parts of cyclohexane is added, 0.0043 parts of chlorohydride carbonyltris (triphenylphosphine) ruthenium is added, and hydrogen is added. The hydrogenation reaction was carried out at a pressure of 6 MPa and 180 ° C. for 4 hours. As a result, a reaction solution containing a hydrogenated product of a ring-opening polymer of dicyclopentadiene was obtained. In this reaction solution, hydrogenated substances were precipitated to form a slurry solution.

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

An antioxidant (tetrakis [methylene-3- (3', 5'-di-t-butyl-4'-hydroxyphenyl) propionate] is added to 100 parts of the hydrogenated compound of the obtained dicyclopentadiene ring-opening polymer. Methane; BASF Japan's "Irganox (registered trademark) 1010") After mixing 1.1 parts, a twin-screw extruder (product name TEM-37B) equipped with four die holes with an inner diameter of 3 mmΦ, manufactured by Toshiba Machinery Co., Ltd. ), A strand-shaped molded body was formed by hot melt extrusion molding, and then shredded with a strand cutter to obtain a pellet-shaped hot melt extrusion molded body.
The operating conditions of the twin-screw extruder are itemized below.
・ Barrel set temperature = 270 or more and 280 ° C or less ・ Die set temperature = 250 ° C
・ Screw rotation speed = 145 rpm

[Manufacturing Example 2: Original film]
The pellet-shaped molded product obtained in Production Example 1 is molded into a raw film having a width of about 600 mm and a thickness of 40 μm by a thermal melt extrusion film molding machine equipped with a T-die, and a masking film is attached to the raw film. , This was rolled up as a roll. As a result, a roll of the original film was obtained. The operating conditions of the film forming machine are listed below in a bulleted list.
・ Barrel temperature setting = 280 ° C or higher and 300 ° C or lower ・ Die temperature = 270 ° C
・ Screw rotation speed = 50 rpm
・ Cast roll temperature = 80 ℃
-The line speed was adjusted so that the thickness of the raw film was 40 μm.

The raw film was unwound from the roll of the obtained raw film, the central portion in the width direction was cut out, and the elongation at break was measured and found to be more than 100%.

[Example 1]
(1-1. Crystallization)
The raw fabric film was pulled out from the roll of the raw fabric film obtained in Production Example 2, the masking film was continuously peeled off, and then the raw fabric film was conveyed in an oven. The film was transported by gripping both ends of the film in the width direction with a large number of clips and guiding the clips to run by a pair of rails arranged along the transport path at both ends of the film in the width direction. As the oven, an oven divided into a plurality of zones and capable of controlling the temperature in a state where there is a temperature difference between a certain region from the upstream to the downstream of the transport path and another region was used. The following treatments (i) to (ii) were performed by adjusting the transport speed, the temperature of each region in the oven, and the arrangement of the rails. In the following, unless otherwise specified, the distance between the pair of rails is constant, and the film is conveyed in a state where the dimensions in the width direction are not changed. Further, in the following, the distance between a plurality of clips on each rail (that is, the distance between a certain clip and the clip adjacent to the upstream side thereof and the distance between the clips adjacent to the downstream side thereof) is changed in the transport path. The clip was run while maintaining equal intervals.

Treatment (i): The raw film was heat-treated at 150 ° C. for 30 seconds.
Treatment (ii): Immediately after the treatment (i), the film was heat-treated at 170 ° C. for 15 seconds to obtain a crystallized film.
Immediately after the treatment (ii) was completed, the crystallized film was taken out of the oven. Both ends of the crystallized film were trimmed, a masking film was attached, and the film was wound as a roll. The central portion in the width direction of the obtained crystallization film was cut out, and the crystallinity and the elongation at break were measured. The crystallinity was 29% and the elongation at break was 18%.

(1-2. Heat shrinkage reduction treatment)
The crystallized film was pulled out from the roll obtained in (1-1), the masking film was continuously peeled off, and then the crystallized film was conveyed in an oven. The film was transported by gripping both ends of the film in the width direction with a large number of clips and guiding the clips to run by a pair of rails arranged along the transport path at both ends of the film in the width direction. The following treatments (iii) to treatments (vi) were performed by adjusting the transport speed, the temperature of each region in the oven, and the arrangement of the rails.

Treatment (iii): Immediately after the crystallized film is placed in the oven, the film is heat-treated at 170 ° C. for 5 seconds, and at the same time, the widthwise dimension of the film is expanded from the start time to the end time of the treatment (iii). And stretched. Dimensional expansion in the width direction was done by arranging the rails so that the distance between the rails increased as the film moved from upstream to downstream. The magnification of the extension of the dimension in the width direction was 1.05 times.
Treatment (iv): Immediately after the treatment (iii), the film was heat treated at 170 ° C. for 15 seconds.
Treatment (v): Immediately after the treatment (iv), the film was heat-treated at 170 ° C. for 5 seconds, and at the same time, the width direction of the film was reduced between the start time and the end time of the treatment (v). Dimensional shrinkage in the width direction was performed by arranging the rails so that the distance between the rails was reduced as the film moved from upstream to downstream. The magnification of the reduction of the dimension in the width direction was set to 0.95 times.
Treatment (vi): Immediately after the treatment (v), the film was heat-treated at 170 ° C. for 15 seconds to obtain a product film.
Immediately after the treatment (vi) was completed, the product film was taken out of the oven. Both ends of the product film were trimmed, a masking film was attached, and this was wound as a roll. The central portion in the width direction of the obtained product film was cut out, and the heat shrinkage in the longitudinal direction and the width direction and the breaking elongation in the longitudinal direction were measured. The thermal shrinkage in the longitudinal direction and the thermal shrinkage in the width direction were 0.18% and −0.04%, respectively, and the elongation at break was 25%. The crystallinity of the product film was 36%.

[Example 2]
Except for the following changes, the same operation as in Example 1 was performed to obtain a product film and evaluated. The results are shown in Tables 1 to 3.
-The film after the treatment (iv) was used as a product film without performing the treatments (v) and (vi), and was taken out of the oven immediately after the treatment (iv) was completed.

[Example 3]
Except for the following changes, the same operation as in Example 1 was performed to obtain a product film and evaluated. The results are shown in Tables 1 to 3.
In the treatment (i), the film was heat-treated at 150 ° C. for 30 seconds, and at the same time, the widthwise dimension of the film was expanded and stretched from the start time to the end time of the treatment (i). Dimensional expansion in the width direction was done by arranging the rails so that the distance between the rails increased as the film moved from upstream to downstream. The magnification of the expansion of the dimension in the width direction was set to 1.2 times.

[Example 4]
Except for the following changes, the same operation as in Example 1 was performed to obtain a product film and evaluated. The results are shown in Tables 1 to 3.
In the treatment (i), the film was heat-treated at 150 ° C. for 30 seconds, and at the same time, the widthwise dimension of the film was expanded and stretched from the start time to the end time of the treatment (i). Dimensional expansion in the width direction was done by arranging the rails so that the distance between the rails increased as the film moved from upstream to downstream. The magnification of the expansion of the dimension in the width direction was set to 1.2 times.
-The film after the treatment (iv) was used as a product film without performing the treatments (v) and (vi), and was taken out of the oven immediately after the treatment (iv) was completed.

[Comparative Example 1]
Except for the following changes, the same operation as in Example 1 was performed to obtain a product film and evaluated. The results are shown in Tables 1 to 3.
-The crystallization film obtained in the treatment (ii) of Example 1 was used as it was as a product film without performing the treatments (iii) to (vi), and the heat shrinkage and the crystallinity in the longitudinal and width directions were measured. ..

[Comparative Example 2]
Except for the following changes, the same operation as in Example 1 was performed to obtain a product film and evaluated. The results are shown in Tables 1 to 3.
In the treatment (i), the film was heat-treated at 150 ° C. for 30 seconds, and at the same time, the widthwise dimension of the film was expanded and stretched from the start time to the end time of the treatment (i). Dimensional expansion in the width direction was done by arranging the rails so that the distance between the rails increased as the film moved from upstream to downstream. The magnification of the expansion of the dimension in the width direction was set to 1.2 times.
-The crystallization film obtained in the treatment (ii) of Example 1 was used as it was as a product film without performing the treatments (iii) to (vi), and the heat shrinkage and the crystallinity in the longitudinal and width directions were measured. ..

[Comparative Example 3]
Except for the following changes, the same operation as in Example 1 was performed to obtain a product film and evaluated. The results are shown in Tables 1 to 3.
-The raw fabric film was pulled out from the roll of the raw fabric film obtained in Production Example 2 without performing the treatments (i) and (ii), and the raw fabric film was used as it was for the treatment (iii). Further, instead of measuring the crystallinity and the elongation at break of the crystallized film, the crystallinity and the elongation at break were measured for the raw film.
-The film after the treatment (iv) was used as a product film without performing the treatments (v) and (vi), and was taken out of the oven immediately after the treatment (iv) was completed.

[Comparative Example 4]
Except for the following changes, the same operation as in Example 1 was performed to obtain a product film and evaluated. The results are shown in Tables 1 to 3.
-The raw fabric film was pulled out from the roll of the raw fabric film obtained in Production Example 2 without performing the treatments (i) and (ii), and the raw fabric film was used as it was for the treatment (iii). Further, instead of measuring the crystallinity and the elongation at break of the crystallized film, the crystallinity and the elongation at break were measured for the raw film.

The outline and results of the operations of Examples and Comparative Examples are shown in Tables 1 to 3.

In Example 1, Example 2, and Comparative Example 1, the same treatment is performed up to the treatment (ii), but due to experimental errors, the numerical values of the crystallinity and the elongation at break after the treatment (ii) are slightly different. There was variation. The same applies to Example 3, Example 4, and Comparative Example 2.

As is clear from the results of Examples and Comparative Examples, a specific crystallized film specified in the production method of the present invention is prepared (Production Example 1 to treatment (i) to treatment (ii)), and a specific stretching step is performed. It can be seen that in the examples subjected to (treatments (iii) to (iv)), the resin film of the present invention having a small elongation at break and, as a result, a small heat shrinkage in the longitudinal direction was obtained. Further, it can be seen that in the examples in which the relaxation steps (treatments (v) to (vi)) were performed, a preferable product film having a small heat shrinkage rate in the width direction was obtained.

Claims (7)

A long resin film containing a crystalline alicyclic structure-containing polymer, having a breaking elongation of 30% or less at a temperature of 150 ° C. and heat shrinkage in the longitudinal direction at 145 ° C. for 1 hour. A resin film having a rate of 0.30% or less. The resin film according to claim 1, wherein the crystallinity is 20% or more and 50% or less. The method for producing a resin film according to claim 1 or 2.
A preparation step (1) for preparing a crystallized film containing a crystalline alicyclic structure-containing polymer and having a breaking elongation at a temperature of 150 ° C. of 30% or less, and a heat shrinkability by treating the crystallized film. Including the heat shrinkage reduction step (2) to reduce
A method for producing a resin film, wherein the heat shrinkage reducing step (2) includes a stretching step (2-1) for stretching the crystallized film. The heat shrinkage reduction step (2) includes a relaxation step (2-2) in which the crystallized film is subjected to a relaxation treatment after the stretching step (2-1).
In the relaxation step (2-2), the crystallized film is held in a manner that allows the crystallized film to shrink in a direction parallel to the stretching direction in the stretching step (2-1). The method for producing a resin film according to claim 3, which comprises heating the crystallized film. The preparation step (1) is a step of preparing a raw fabric film (1-1), and a crystal obtained by heating the raw fabric film to increase the crystallinity of the raw fabric film to obtain the crystallized film. The method for producing a resin film according to claim 3 or 4, which comprises a crystallization step (1-2). The method for producing a resin film according to any one of claims 3 to 5, wherein the crystallinity of the crystallized film is 10% or more. The method for producing a resin film according to any one of claims 3 to 6, wherein the stretching direction in the stretching step (2-1) is the width direction of the crystallized film.