JP2942847B2 - Liquid crystal polymer film manufacturing apparatus and liquid crystal polymer film manufacturing method using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an apparatus for producing a liquid crystal polymer film useful for producing a film from a liquid crystal polymer forming an anisotropic melt, and an apparatus using the same. The present invention relates to a method for producing a liquid crystalline polymer film.

[Related Art and Problems to be Solved by the Invention] Liquid crystalline polymers forming an anisotropic melt, that is, thermotropic liquid crystalline polymers belong to the domain of engineering plastics, and have mechanical properties, dimensional stability, and chemical resistance. It has excellent properties such as heat resistance, heat resistance, and electrical properties, and is attracting attention as a film material that satisfies the required performance in various fields. This liquid crystalline polymer has a high orientation, as is clear from the fact that a split fiber having a high elastic modulus can be obtained by film forming (see Japanese Patent Publication No. 60-42287). Mechanical anisotropy in the direction (hereinafter, referred to as MD direction) and the width direction orthogonal to the MD direction (hereinafter, referred to as TD direction) is large.

Therefore, for example, Japanese Patent Publication No. 63-33450 and Japanese Unexamined Patent Publication No.
JP-A-102234 discloses that, during film formation by the inflation method, by stretching a cylindrical film in the MD and TD directions, a large mechanical strength can be obtained, and a small anisotropic liquid crystalline polymer film can be obtained. Have been. In addition, film forming by the inflation method,
Usually, one extruded upward from the annular slit of the inflation die is expanded and stretched in the TD direction,
It is stretched in the MD direction by taking up while being folded by the nip roll of the take-up machine. At that time, a pair of guide plates arranged in an inverted V shape at a distance of about 2 to 5 m from the die guide the cylindrical film while opposing the opposing surfaces thereof, and are folded by a nip roll of a take-up machine.

However, the liquid crystal polymer has many wrinkles when the stretched tubular film is folded, probably because of its high elastic modulus. In addition, the liquid crystalline polymer not only has a relatively low melt viscosity, but also the strength (lumpy) of the film in the molten state.
But smaller than olefin polymers and the like. Therefore,
When the molten liquid crystalline polymer is extruded upward from the annular slit of the inflation die, its own weight acts on the cylindrical film in the molten state, which tends to cause uneven wall thickness, making it difficult to form a uniform cylindrical film. . In addition, the tubular film is not only easily ruptured from the thin portion of the tubular film due to the expansion, but also rolls the tubular film called a bubble. Therefore, it is difficult to stretch the tubular film stably and uniformly, and the mechanical anisotropy of the film is not significantly improved.

Accordingly, an object of the present invention is to provide a liquid crystal polymer film manufacturing apparatus capable of forming a uniform tubular film without uneven thickness, and capable of stretching the tubular film stably and uniformly and obtaining a film without wrinkles. Is to provide.

Another object of the present invention is to provide a method for producing a liquid crystalline polymer film exhibiting the above-mentioned excellent characteristics.

[Constitution of the Invention] In order to achieve the above object, the present inventor has conducted intensive studies. As a result, in the inflation molding method, when a melt of a liquid crystalline polymer is extruded downward from an annular slit, a cylindrical shape is formed. The film can be stably and uniformly expanded while hanging down by its own weight, and can be smoothly stretched. (B) The temperature of the cylindrical film at the time of folding and the angle at which the cylindrical film is guided greatly contribute to the generation of wrinkles. And completed the present invention.

That is, in the present invention, an annular slit through which a liquid crystalline polymer forming an anisotropic melt is extruded, and a gas supply path for pressurizing gas into a hollow portion of a cylindrical film extruded from the annular slit are formed. An inflation die,
An apparatus having a guide member that guides an opposing surface of a tubular film expanded by pressurized gas while approaching the facing surface, and a take-up machine that folds the tubular film guided by the guide member while folding the tubular film. The slit faces downward, and a heat retaining cylinder for keeping the tubular film warm is provided between the expansion start portion of the expanded tubular film and the guide member, and the guide member has an angle of at least 10 °. Provided is an apparatus for manufacturing a V-shaped liquid crystalline polymer film having a 50 ° inclined portion.

Further, the present invention is a method using the manufacturing apparatus, wherein a liquid crystalline polymer forming an anisotropic melt is melted and extruded downward from an annular slit, and a generated cylindrical film is taken off, A method for producing a liquid crystalline polymer film by a method of stretching a tubular film stretched in a width direction orthogonal to a take-off direction and folding the stretched tubular film while guiding the stretched tubular film with a guide member while keeping the temperature of the heating tube.

Furthermore, in the present invention, in the above-mentioned device, the guide member is disposed between the vicinity of the expansion start portion of the expanded tubular film and the folded portion without using a heat retaining tube, and the guide member is provided. Provided is an apparatus for manufacturing a liquid crystal polymer film formed in a V-shape at an angle of 10 to 45 °.

Further, the present invention provides a method using the above-mentioned apparatus, wherein a liquid crystalline polymer which forms an anisotropic melt is melted and extruded downward from an annular slit, and a formed cylindrical film is drawn in a take-up direction, Provided is a method for producing a liquid crystalline polymer film by a method of stretching a tubular film stretched in a width direction orthogonal to a take-out direction and folding the stretched tubular film while guiding the film by the guide member without using a heat retaining tube.

In the present specification, the term “liquid crystalline polymer” means a thermotropic liquid crystalline polymer and a composition thereof which are softened and flowable by heating, can be molded, and exhibit an anisotropic melt having birefringence when melted.

A film includes all relatively thin, substantially flat structures that are sometimes referred to in the art as sheets or the like.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a schematic view showing a manufacturing apparatus and a manufacturing method of a liquid crystalline polymer film which is an example of the present invention.

The liquid crystalline polymer supplied from the hopper (1) is melted by an extruder (3), extruded by a screw (2), and supplied to an inflation die (4) attached to the extruder (3). In the die (4), the liquid crystalline polymer is extruded as a cylindrical film (6) downward from an annular slit (5) facing downward through an annular channel.

The first feature of the present invention is that a liquid crystal polymer is
At the point where it is pushed downward from the annular slit (5). When the cylindrical film (6) is extruded downward, unlike the case where it is extruded upward, its own weight does not act on the cylindrical film (6). Without hanging, a cylindrical film (6) having a uniform thickness can be formed while hanging down by its own weight. In addition, the melt extrusion temperature of the liquid crystalline polymer that can uniformly and stably expand the tubular film (6) can be selected according to the type of the structural unit of the polymer, the composition ratio, and the like. Suitable melt extrusion temperature of the liquid crystalline polymer is, for example, 180 to 360 ° C.
You can choose from a range of degrees.

The gap between the annular slits (5), that is, the lip clearance is usually 0.2 to 10 mm, preferably about 0.5 to 4 mm. The diameter of the annular slit (5) can be set according to the width of the film to be formed, and is not particularly limited. However, if the diameter of the annular slit (5) is too large, the tubular film (6) can be stably expanded. It is difficult to perform the film formation, and the characteristics of the film are likely to be deteriorated. Therefore, the diameter of the annular slit (5) is preferably 200 mm or less, particularly preferably 120 mm or less.

A gas supply pipe (7) is connected to the die (4) for supplying a gas such as air, nitrogen or carbon dioxide to the hollow portion of the tubular film (6) to expand the tubular film (6). ing. An air ring (8) is provided below the die (4) to cool the cylindrical film (6) extruded from the die (4) to a predetermined temperature until it is expanded. . The air ring (8) is not always necessary, and the tubular film (6) may be cooled naturally.

The gas supplied by the gas supply pipe (7) is
The cylindrical film (6) called a bubble is stretched in the TD direction orthogonal to the take-off direction by press-fitting into the hollow portion of the cylindrical film (6) through the gas supply path (7a) in the die (4). And the nip roll of the take-off machine (11a) (11b)
Draft while stretching in MD direction. The cylindrical film (6) extruded from the die (4) expands at a position where the temperature of the cylindrical film (6) and the pressure of the pressurized gas are balanced.

The temperature at which the tubular film (6) is expanded is usually at least the secondary transition temperature of the liquid crystalline polymer and 10 to 100 ° C., particularly about 20 to 70 ° C. lower than the extrusion temperature. If the film temperature is too low, the stretching effect decreases, and if it is too high, it is difficult to expand the tubular film uniformly.

TD and MD stretch ratio, TD stretch ratio and MD
The ratio of the stretching ratio in the direction may be within a range that does not prevent uniform stretching. The draw ratio in the TD direction, that is, the blow ratio (Dt
d) is, for example, about 1.5 to 10 times, preferably about 2.5 to 6 times. The stretching ratio Dmd in the MD direction is, for example, 1.5 to 40 times,
Preferably it is about 5 to 25 times.

 The ratio between Dtd and Dmd is, for example, about 0.1 ≦ Dtd / Dmd <2.5, preferably about 0.4 ≦ Dtd / Dmd ≦ 1.5.

Then, in order to prevent wrinkles from occurring in the expanded tubular film (6), a tubular member is provided between the expansion start portion of the tubular film (6) and the pair of guide members (10a) (10b). A heat retaining cylinder (9) for keeping the film (6) warm is provided.
The pair of guide members (10a) and (10b) have an angle of 10 to 50 °.
It is arranged in a letter shape, and is guided while the opposing surfaces of the cylindrical film (6) are brought close to each other. Further, the heat retaining cylinder (9) is formed of an upper sizing ring (9a) and a tubular body (9b) hanging down from the sizing ring (9a) in a tubular shape. As the cylindrical body (9b), for example, cloth, metal, or the like can be used.

By providing the heat retaining cylinder (9), the elastic modulus of the liquid crystalline polymer can be reduced, and the tubular film (6) can be softened and folded. Moreover, the roll of the tubular film (6) can be suppressed by the heat retaining cylinder (9). Therefore, the tubular film (6) can be smoothly folded while preventing wrinkles from occurring.

The temperature in the heat retaining cylinder (9) may be at least the secondary transition temperature of the liquid crystalline polymer and within a range that can prevent fusion at the time of folding. The temperature in the heat retaining cylinder (9) is, for example, 80 to 20.
It is about 0 ° C.

The tubular film (6) stretched as described above is guided by the guide members (10a) (10b) with the opposing surfaces approaching, and is taken up and folded by the nip rolls (11a) (11b). The film temperature when passing through the nip rolls (11a) and (11b) is 50 to 170 ° C., preferably 70 to 170 ° C.
~ 150 ° C.

The film folded by the nip roll (11a) (11b)
After passing through the roller (12) and the pair of rollers (13a) (13b), the slit is slit by the slitter (14). The two liquid crystal polymer films (16a) and (16b) generated by the slit pass through a pair of rollers (15a) and (15b), and are taken up by a take-up roll (17).
a) It is wound up in (17b).

When producing a liquid crystalline polymer film according to the production apparatus and production method of the present invention, a film having a uniform thickness without wrinkles can be obtained. In addition, the tubular film (6) can be stretched uniformly and stably, and the tubular film (6) is expanded and stretched in the TD direction, while being taken up and stretched in the MD direction. Is possible. Therefore, the obtained liquid crystalline polymer film has not only high tensile modulus and tensile strength but also extremely low anisotropy and excellent mechanical properties. Particularly preferred liquid crystalline polymer films exhibit isotropic properties.

FIG. 2 is a schematic view of a main part showing another example of the present invention. Note that the same elements as those in FIG. 1 are described with the same reference numerals.

In this example, a pair of guide members for guiding the cylindrical film (6) extruded from the annular slit (not shown) of the die (4) while approaching the opposing surfaces without providing the heat retaining cylinder (9). (20a) and (20b) are replaced with a tubular film (6)
Is located close to the expansion start side.

More specifically, when the cylindrical film (6) is extruded downward from the die (4), the expansion start portion of the cylindrical film (6) and the upper ends of the pair of guide members (20a) (20b) are connected. When the distance is set to about 2 to 5 m, similarly to the conventional inflation molding method in which the cylindrical film is extruded upward, the cylindrical film (6) is greatly cooled while reaching the guide members (20a) (20b). . When the tubular film (6) is cooled, its elastic modulus increases, and a large number of wrinkles occur when folded by the nip rolls (11a) (11b). On the other hand, when the pair of guide members (20a) and (20b) are brought close to the expansion start side of the cylindrical film (6), cooling of the expanded cylindrical film (6) can be suppressed, and the pair of guide members can be suppressed. (20
a) Rolling can be prevented by (20b). Therefore, the tubular film (6) can be smoothly folded without causing wrinkles in the tubular film (6).

The expansion start portion of the tubular film (6) may be above or below the upper ends of the guide members (20a) (20b). The cylindrical film (6) is connected to a guide member (20
a) When expanding above the upper end of (20b), the distance L between the expansion start part and the upper end of the guide member (20a) (20b)
Is usually 0 to 1 m, preferably about 0 to 50 cm. When the tubular film (6) is expanded below the upper ends of the guide members (20a) (20b), the guide member (20a)
(20b), the distance between the upper end and the expansion start part is usually 0 to 1
m.

FIG. 3 is a schematic view of a main part showing still another example of the present invention.

In this example, the annular slit of the die (4) (not shown)
A pair of guide members (30a) (30b) for guiding the opposing surfaces of the cylindrical film (6) extruded from the same while approaching each other are arranged at an acute angle. That is, when the angle of the pair of guide members (30a) (30b) arranged in a V-shape is reduced, it is possible to fold the cylindrical film (6) while gradually approaching the opposing surfaces thereof. Therefore, the tubular film (6) can be smoothly folded while preventing wrinkles from occurring.

The angle of the pair of guide members (30a) (30b) is selected in a range smaller than the angle of the conventional guide member of 40 to 70 °, and is 10 to 45 ° (for example, 10 to 40 °), preferably
It is about 15-30 ゜.

In the apparatus shown in FIGS. 2 and 3, as in the apparatus shown in FIG. 1, the expansion start portion of the tubular film (6) and the guide members (20a) (20b) (30a) (30b) are connected. A heat retaining cylinder may be provided between them.

FIG. 4 is a schematic view of a main part showing another example of the present invention. In this example, similarly to the apparatus shown in FIG. 1, a heat retaining cylinder (9) for keeping the expanded tubular film (6) warm and a pair of guide members (40a) (40b) are provided. The nip rolls (11a) (11) of the pair of guide members (40a) (40b)
b) The side is formed in a parallel plate shape. That is, each of the guide members (40a) (40b) includes an inclined portion (41a) (41b) on the guide start end side, that is, the die (4) side, and a guide end portion side.
That is, it is composed of the parallel plate portions (42a) (42b) on the nip roll (11a) (11b) side.

In such a device, the press-fitting gas exerts a tension on the parallel plate portions (42a) (42b) of the guide members (40a) (40b) in a direction perpendicular to the facing direction of the cylindrical film (6), that is, in the front-rear direction of the drawing. Acts, the tubular film (6) having the opposing surface close thereto can be folded and tensed without wrinkling.

In the apparatus shown in FIG. 4, the heat retaining cylinder (9) is not always necessary, and the pair of guide members (40a) (4
0b) at the upper end, as in the device shown in FIGS.
It may be located near the expansion start portion of the tubular film (6). The nip roll (11a) (11b) side of the pair of guide members (40a) (40b) is not limited to a parallel plate shape. For example, if the angle between the pair of guide members (40a) (40b) on the nip roll (11a) (11b) side, that is, the guide end portion side, is smaller than the inclined portion (41a) (41b) on the die (4) side. Good.

In order to prevent wrinkles, a pair of guide members (40
a) The length of the guide end part with a small angle of (40b) is 20cm
It is preferable that this is the case.

The liquid crystalline polymer that can be used in the present invention is not particularly limited, and examples thereof include polyester, polyesteramide, polythiol ester, polyazomethine, and polyester carbonate.

Among these liquid crystalline polymers, aromatic liquid crystalline polymers having excellent mechanical strength, mechanical properties, dimensional stability, chemical resistance, heat resistance, and electrical properties, particularly fully aromatic polyesters, fully aromatic polyesters Amides are preferred.

The molecular weight of the liquid crystalline polymer cannot be determined unconditionally because it differs depending on the type, but in the case of a suitable wholly aromatic polyester, for example, the weight average molecular weight is about 2,000 to 20.
0,000, preferably about 10,000-50,000, more preferably about 20,000-25,000. Also, the molecular weight of a suitable wholly aromatic polyesteramide is, for example, about 5,000 to 50,000
0, preferably about 10,000-30,000, more preferably 15,
000 to 17,000.

In the production of the film of the present invention, the liquid crystalline polymer can be used alone or as a polymer composition. The polymer composition further includes a polymer that forms an anisotropic molten phase; a thermoplastic resin that does not form an anisotropic molten phase; a thermosetting resin; a plasticizer, an antioxidant, an ultraviolet absorber, an antistatic agent, Additives such as flame retardants, coloring agents, foaming agents, crosslinking agents, lubricants, etc .; fillers such as inorganic fibers, whiskers, calcium carbonate, highly dispersible silica, alumina, aluminum hydroxide, talc powder, mica, barium sulfate, etc. May be contained. The polymer composition contains at least 50% by weight, preferably at least 80% by weight of the liquid crystalline polymer.

The film obtained as described above is subjected to a heat treatment as necessary. This heat treatment can be performed under tension of the film or without tension. Heat treatment is
It can be performed at a temperature of about 70 to 300 ° C. in an appropriate atmosphere, for example, air, nitrogen, or a vacuum atmosphere. The temperature history cycle of the heat treatment, the heat treatment time, the tension, and the like can be set according to the type of the film and the required physical properties of the film.

Further, the liquid crystal polymer film may be subjected to a surface treatment such as a corona discharge treatment.

The thickness of the liquid crystalline polymer film is not particularly limited, but is usually about 1 to 500 μm, preferably about 10 to 250 μm.

The liquid crystalline polymer film obtained by the apparatus and method of the present invention can be used in various applications such as films for packaging, photographic films, films for recording media such as magnetic recording tapes, and films for electrical insulation.

[Effect of the Invention] In the manufacturing apparatus and the manufacturing method of the present invention, there is no uneven thickness,
A uniform cylindrical film can be formed, the cylindrical film can be stretched stably and uniformly, and a liquid crystal polymer film without wrinkles can be obtained.

EXAMPLES Hereinafter, the present invention will be described in more detail based on examples.

Example 1 The following repeating units [I] and [II] A pellet of a liquid crystalline polymer (Vectra A900, trade name, manufactured by Polyplastics Co., Ltd.) composed of polyester was dried in advance at a temperature of 150 ° C. for 8 hours, and using an apparatus as shown in FIG. It was extruded downward under the following conditions, stretched, and taken up while being folded by a nip roll.

Extrusion direction: down Extrusion temperature: 280 ° C Diameter of annular slit: 50mm Lip clearance: 1.0mm Blow ratio (Dtd): 5.0 times Draft ratio (Dmd): 6.0 times Start of expansion of tubular film: 25cm below die Inside diameter and length of: 27cmφ × 30cm Temperature in the heat insulation cylinder: 180 ° C Distance between the upper end of the heat insulation cylinder and the start of expansion of the tubular film: 5
cm Angle of the pair of guide plates: 45 ° Take-up speed of the cylindrical film: 15 m / min. Example 2 As shown in FIG. 2, the expansion start portion of the cylindrical film and the pair of guides were used without using a heat retaining cylinder. A liquid crystalline polymer film was obtained in the same manner as in Example 1 except that the distance from the upper end of the plate was set to 0 cm.

Example 3 As shown in FIG. 3, the distance between the start of expansion of the tubular film and the upper ends of the pair of guide plates was 5 cm, and the angle of the pair of guide plates was 20 ° without using a heat retaining tube. A liquid crystal polymer film was obtained in the same manner as in Example 1 except for the above.

Example 4 As shown in FIG. 4, instead of the pair of guide plates of Example 1, an inclined portion on the die side (length 60 cm, angle 50 °) and a parallel plate portion on the nip roll side (length 15 cm) Except for using a pair of guide members composed of
A liquid crystalline polymer film was obtained.

Comparative Example 1 A liquid crystalline polymer film was obtained in the same manner as in Example 1 without using a heat retaining cylinder.

Comparative Example 2 A cylindrical film was extruded upward using the liquid crystalline polymer of Example 1 under the following conditions without using a heat retaining cylinder to form a film.

 Extrusion direction: Upward Extrusion temperature: 280 ° C. Lip clearance: 1.0 mm Blow ratio (Dtd): 3.0 times Draft ratio (Dmd): 12.0 times Film formability was evaluated based on the following criteria.

Wrinkles generated Excellent: No wrinkles generated Good: Slight wrinkles generated Not possible: Many wrinkles generated Bubble inflatability Excellent: Air pressure can be applied sufficiently Good: Inflatability is slightly inferior Allowed: Predetermined air pressure Cannot be applied. Not possible: Can be expanded only for a short time and bubbles burst. The results of film formability are shown in the table.

As is clear from the table, wrinkles do not occur in the film of each example, and the film can be stretched uniformly and stably.

[Brief description of the drawings]

FIG. 1 is a schematic view showing a production apparatus and a production method of a liquid crystalline polymer film which is an example of the present invention, FIG. 2 is a schematic view of a main part showing another example of the present invention, and FIG. FIG. 4 is a schematic diagram of a main part showing another example, and FIG. 4 is a schematic diagram of a main part showing another example of the present invention. (3) ... extruder, (4) ... inflation die, (5) ... annular slit, (6) ... tubular film, (7a) ... gas supply path, (9) ... heat insulation cylinder, (10a) (10b) (20a) (20b) (30a) (30b) (40a)
(40b): Guide member (11a) (11b): Nip roll (16a) (16b): Liquid crystalline polymer film

Claims (4)

(57) [Claims] 1. An inflation having an annular slit through which a liquid crystalline polymer forming an anisotropic melt is extruded, and a gas supply passage for pressurizing gas into a hollow portion of a cylindrical film extruded from the annular slit. A die, a guide member for guiding the opposing surface of the tubular film expanded by pressurized gas while approaching the facing surface, and a take-up machine for folding and taking the tubular film guided by the guide member, wherein The annular slit of the die faces downward, and a heat retaining cylinder for keeping the tubular film warm is provided between the expansion start portion of the expanded tubular film and the guide member, and the guide member is at least provided. A manufacturing apparatus for a liquid crystal polymer film formed in a V-shape having an inclined portion at an angle of 10 to 50 °. 2. An inflation having an annular slit through which a liquid crystalline polymer forming an anisotropic melt is extruded, and a gas supply passage for pressurizing gas into a hollow portion of a cylindrical film extruded from the annular slit. A die, a guide member for guiding the opposing surface of the tubular film expanded by pressurized gas while approaching the facing surface, and a take-up machine for folding and taking the tubular film guided by the guide member, wherein The annular slit of the die faces downward, and the guide member is disposed between the vicinity of the expansion start portion of the expanded tubular film and the folded portion, and the guide member has an angle of 10 to 45 °. An apparatus for producing a liquid crystal polymer film formed in a V-shape. 3. A method using the production apparatus according to claim 1, wherein a liquid crystalline polymer forming an anisotropic melt is melted and extruded downward from an annular slit, and the formed cylindrical film is taken off. A method for producing a liquid crystalline polymer film, comprising: stretching a tubular film stretched in a width direction perpendicular to the direction and the take-up direction, and folding the stretched tubular film while guiding the stretched tubular film with a guide member while keeping the temperature of the heat retaining tube. 4. A method using the production apparatus according to claim 2, wherein a liquid crystalline polymer forming an anisotropic melt is melted and extruded downward from an annular slit, and a produced cylindrical film is taken off. A method for producing a liquid crystalline polymer film, wherein the liquid crystal polymer film is stretched in a width direction orthogonal to the direction and the take-up direction, and the stretched tubular film is guided by the guide member according to claim 2.