JPH0453728A - Production equipment and manufacture of liquid crystalline polymer film used therewith - Google Patents

Abstract

PURPOSE:To make it possible to produce homogeneous tubular film having uniform section and, at the same time, to stably and uniformly stretch the tubular film so as to obtain wrinkle-free film by a method wherein a heat retaining tube, which retains the heat of the tubular film, is provided between tire expansion starting part of expanding tubular film and guide members. CONSTITUTION:A heat retaining tube 7, which retains the heat of tubular film 6, is provided between the expansion starting part of the tubular film 6 and a pair of guide members 10a and 10b. A pair of the guide members 10a and 10b are arranged in a V-shape so as to guide the opposing faces of the tubular film 6 so as to bring them close to each other. The heat retaining tube 9 consists of an upper sizing ring 9a and a tube 9b, which hangs tubularly from the sizing ring 9a. As the tube 9b to be used, cloth, metal or the like can be cited. By providing the heat retaining tube 9, the elastic modulus of liquid crystalline polymer, resulting in allowing to soften the tubular film 6 so as to fold it. Further, the rolling of the tubular film 6 can be suppressed by the heat retaining tube 9. Accordingly, under the state that wrinkle is prevented from developing, the tubular film 6 can be smoothly folded up.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a liquid crystalline polymer film manufacturing apparatus useful for manufacturing a film from a liquid crystalline polymer that forms an anisotropic melt, and an apparatus using the same. The present invention relates to a method for producing a liquid crystalline polymer film.

[Prior art and problems to be solved by the invention] Liquid crystalline polymers that form anisotropic melts, that is, thermo-I-ropic liquid crystalline polymers, belong to the field of engineering plastics and have mechanical properties and 11 methods. It has excellent stability, chemical resistance, heat resistance, electrical properties, etc., and is designated as a film material that satisfies the performance requirements in various fields.

This liquid crystalline polymer can be made into one split fiber with a high elastic modulus by film molding (Japanese Patent Publication No. 60-1999-1).
42287), it has a high degree of orientation, so it is highly oriented in the longitudinal direction of the film, that is, in the take-up direction (
The mechanical anisotropy is large in the width direction (hereinafter referred to as the MD direction) and the width direction perpendicular to the MD direction (hereinafter referred to as the TDH direction).

Therefore, for example, in Japanese Patent Publication No. 63-33450 and Japanese Patent Application Laid-open No. 11i1-102234, mechanical strength is increased by stretching a cylindrical film in the MD direction and the TD force direction during film forming by the inflation method. It is disclosed that a liquid crystalline polymer film with small anisotropy can be obtained. In film forming by the inflation method, a cylindrical film is usually extruded upward from an annular slit of an inflation die, is expanded and stretched in the TD force direction, and is then folded and pulled using two tube rolls of a pulling machine. By taking the film, it is stretched in the MD direction. At that time, place the inverted V about 2 to 5 meters away from the die.
A pair of guide plates arranged in a letter shape guides the opposing surfaces of the cylindrical film while bringing them close together, and the film is folded by the nip rolls of the take-up machine.

However, because the liquid crystalline polymer has a high elastic modulus, many wrinkles occur when the stretched cylindrical film is folded. Furthermore, liquid crystalline polymers not only have a relatively low melt viscosity, but also have a film strength (fl) lower than that of olefin polymers in a molten state. Therefore, when extruding a molten liquid crystalline polymer upward through the annular slit of an inflation die, its own weight acts on the molten cylindrical film, which tends to cause uneven thickness and makes it difficult to form a uniform cylindrical film. It is. In addition, as the tube expands, it bursts from the thin wall portion of the tube, causing not only damage to the product but also causing the tube, which is called a bubble, to sway horizontally. Therefore, it is difficult to stretch the cylindrical film stably and uniformly, and the mechanical anisotropy of the film is not significantly improved.

Therefore, an object of the present invention is to provide an apparatus for producing a liquid crystalline polymer film that can form a uniform cylindrical film without uneven thickness, can stably and uniformly stretch the cylindrical film, and can obtain a wrinkle-free film. The purpose is to propose the following.

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

[Structure of the Invention] In order to achieve the above [1], as a result of intensive studies, the present inventor found that (a) in the inflation molding method, when extruding a melt of a liquid crystalline polymer downward through an annular slit, The present invention was based on the discovery that the cylindrical film can be expanded stably and uniformly while hanging under its own weight, and can be stretched smoothly; and (b) the temperature of the cylindrical film when folded is greatly involved in the generation of wrinkles. completed. 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 through which gas is pressurized into a hollow part of a cylindrical film extruded from the annular slit are formed. An apparatus comprising an inflation die, a guide member that guides the opposing surfaces of a cylindrical film expanded by pressurizing gas while bringing them close to each other, and a pulling machine that folds and takes over the cylindrical film guided by the guide member, , a liquid crystalline polymer film in which the annular slit of the die faces downward, and a heat-retaining tube for keeping the cylindrical film warm is disposed between the expansion start part of the expanded cylindrical film and the guide member. We provide manufacturing equipment for

Further, the present invention provides the above-mentioned device with the following features: ! Provided is an apparatus for manufacturing a liquid crystalline polymer film, in which the guide member is disposed between the folding part and the vicinity of the expansion start part of the expanded cylindrical film without using a cylinder.

Furthermore, the present invention melts a liquid crystalline polymer that forms an anisotropic melt, extrudes it downward through an annular slit, and stretches the resulting cylindrical film in the take-up direction and in the width direction perpendicular to the take-up direction. , provides a method for producing a liquid crystalline polymer film, in which a stretched cylindrical film is folded while being kept warm with the heat-insulating cylinder or guided with the guide member.

As used herein, the term "liquid crystalline polymer" refers to a thermotropic liquid crystalline polymer that softens and flows upon heating, becomes moldable, and exhibits an anisotropic melt phase having birefringence when melted, and a composition thereof.

A film encompasses any relatively thin, substantially flat structure that is sometimes referred to in the art as a sheet or the like.

The present invention will now be described in detail with reference to the accompanying drawings.

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

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

The first feature of the present invention is that the liquid crystalline polymer is extruded downward through the annular slit (5) of the die (4).

When extruding the cylindrical film (6) downward, unlike when extruding it upward, its own weight does not act on the cylindrical film (6), so even if the liquid crystalline polymer has a small melt viscosity, uneven thickness will occur. It is possible to form a cylindrical film (6) with a uniform thickness while hanging down due to its own weight. Further, the melt extrusion temperature of the liquid crystalline polymer that allows uniform and stable expansion of the cylindrical film (6) can be selected depending on the type and composition ratio of the polymer's structural units. A suitable melt extrusion temperature for the liquid crystalline polymer is, for example, 180 to 36
It can be selected from a range of about 0°C.

The gap of the annular slit (5), that is, the lip clearance, is usually 0.2 to 10+ nm, preferably 0°5 to 4 nm.
It's just a struggle. The diameter of the annular slit (5) can be set depending on the width of the film to be formed, and is not particularly limited.
If the diameter of the annular slit 6) is too large, it will be difficult to stably expand the cylindrical film (6).
The properties of the film deteriorate. Therefore, the annular slit (
The diameter of 5) is preferably 200 mm or less, particularly 120 mm or less.

A gas supply pipe (7) is connected to the die (4) in order to inflate the cylindrical film (6) by supplying a gas such as air, nitrogen, carbon dioxide, etc. to the hollow part of the cylindrical film (6). ing. In addition, a cylindrical film extruded from the die (4) (
A near ring [F]) is provided below the die (4) in order to cool the die (6) to a predetermined temperature until it is expanded. Note that this nearing (8) is not necessarily necessary, and the cylindrical film (6) may be naturally cooled.

By pressurizing the gas supplied by the gas supplying vibrator (7) into the hollow part of the cylindrical film (6) through the gas supply path (7a) in the die (4), a cylindrical film called a bubble is formed. (6) is stretched in the TD force direction perpendicular to the pulling direction, and the nip roll (lla) of the pulling machine (
llb) while taking it up and stretching it in the MD direction while applying a draft. Cylindrical film (6) extruded from die (4)
expands at a position where the temperature of the cylindrical film (6) and the pressure of the injected gas are balanced.

The temperature at which the cylindrical film (6) is expanded is usually
The temperature is higher than the second-order transition temperature of the liquid crystalline polymer and lower than the extrusion temperature by about 10 to 100°C, particularly about 20 to 70°C. If the film temperature is too low, the stretching effect will be reduced, and if it is too high, it will be difficult to uniformly expand the cylindrical film.

The stretching ratio in the TD force direction and the MD direction, and the ratio of the stretching ratio in the TD force direction to the stretching ratio in the MD direction may be within a range that does not prevent uniform stretching. The stretching ratio in the TDH direction, that is, the blow ratio (D Ld) is, for example, about 1.5 to 10 times, preferably about 2.5 to 6 times. Stretching ratio Da in MD direction
d is, for example, 1°5 to 40 times, preferably about 5 to 25 times.

Further, the ratio between Did and Dad is, for example, 0.1≦D
td/Dad<2, 5, preferably 0.4≦D
td/D sd≦1.5.

In order to prevent wrinkles from forming on the expanded cylindrical film (6), between the expansion start part of the cylindrical film (6) and the pair of guide members (10a) (101+),
An insulation 7m n (9) for keeping the cylindrical film (6) warm is provided. A pair of guide members (10a) (10b
) are arranged in a ■-shape and guide the opposing surfaces of the cylindrical film (6) while bringing them close to each other. Moreover, the heat insulation cylinder (9) is
It is formed of an upper sizing ring (9a) and a cylindrical body (9b) that hangs down from the sizing ring (9a) in a cylindrical shape. As the cylinder (9b), for example, cloth, metal, etc. can be used.

By providing this heat retaining cylinder (9), the elastic modulus of the liquid crystalline polymer can be lowered, and the cylindrical film (6) can be softened and folded. Moreover, the heat-insulating cylinder (9) can suppress the horizontal shaking of the cylindrical film (6). Therefore, the cylindrical film (6) can be folded smoothly while preventing the occurrence of wrinkles.

The temperature inside the heat retaining tube (9) may be within a range that is equal to or higher than the second-order transition temperature of the liquid crystalline polymer and prevents fusion during folding. The temperature inside the heat insulating cylinder (9) is, for example, 80 to 2
0 (] 'C or so.

The cylindrical film (6) stretched as described above is guided by the guide part fob (10a) (fob) while bringing the opposing surfaces close to each other, and is guided by the nip roll (Ila) (l
lb) and folded. Nip roll (l la
) (l l b) is passed through the film at a temperature of about 50 to 170°C, preferably about 70 to 150°C.

The film folded by the nip roll (lla) (month b) is folded by the roller (12), a pair of rollers (13a) (+3b
) and then slit by a slitter (14). Pickpocket
Two liquid crystalline polymer films (1
6a) (16b) is a pair of rollers (15a) (15
b) and then wound onto take-up rolls (17a) and (17b).

When manufacturing a liquid crystalline polymer film according to the manufacturing apparatus and manufacturing method of the present invention, a wrinkle-free film with a uniform thickness can be obtained. In addition, the cylindrical film (6) can be stretched uniformly and stably, and the cylindrical film (6) is expanded and stretched in the TDH direction while being taken up and stretched in the MD direction, resulting in simultaneous biaxial orientation. is possible.

Therefore, the obtained liquid crystalline polymer film not only has high tensile modulus and tensile strength, but also has relatively small anisotropy and excellent mechanical properties. A particularly preferred liquid crystalline polymer film exhibits isotropy.

FIG. 2 is a schematic diagram of part f showing another example of the present invention. Note that the same elements as in FIG. 1 will be described with the same reference numerals.

In this example, a pair of guide members are used to guide the opposing surfaces of the cylindrical film (6) extruded from the annular slit (not shown) of the die (4) while bringing them close to each other, without providing the heat retaining cylinder (9). (20a) and (20b) are placed close to the expansion start portion side of the cylindrical film (6).

More specifically, when extruding the cylindrical film (6) downward from the die (4), the expansion start part of the cylindrical film (6) and the upper ends of the pair of guide members (20a) (20b) If the distance is set to about 2 to 5 m, as in the conventional inflation molding method in which the cylindrical film is extruded upward, the cylindrical film (6) is cooled significantly while reaching the guide members (20a) (2ob). Ru. When the cylindrical film (6) is cooled, its elastic modulus increases and the nip roll (l
la) Many wrinkles occur during folding due to (11tr). On the other hand, a pair of guide members (20a) (20b)
When the cylindrical film (6) is brought close to the expansion start part side, cooling of the expanded cylindrical film (6) can be suppressed;
Moreover, the pair of guide members (20a) (20b) can prevent horizontal shaking. Therefore, the cylindrical film (6) can be folded smoothly without causing wrinkles in the cylindrical film (6).

Note that the expansion start part of the cylindrical film (6) is located at the guide part +
4' (20a) (20b) It may be either above or below the upper end. When the cylindrical film (6) is expanded above the upper ends of the guide members (20a) (20b), the expansion start part and the guide member (20a)
The distance from the top of (20b) is usually 0 to 1 m, preferably L
< is about 0 to 5ocIll. Further, when the cylindrical film (6) is expanded below the upper ends of the guide members (20a) (20b), the guide members (20a) (2
The distance between the upper end of 0b) and the inflation start part is usually 0 to 1
It is about m.

FIG. 3 is a schematic diagram of main parts showing still another example of the present invention.

In this example, a pair of guide members (!1Oa) (301
+) are placed at an acute angle. In other words, a pair of guide members arranged in a ■ shape (30a) (30b)
When the angle is made small, the opposing surfaces of the cylindrical film (6) can be folded while gradually approaching each other. Therefore, the cylindrical film (6) can be folded smoothly while preventing the occurrence of wrinkles.

The angle of the pair of guide members (30a) (30b) is selected within a range smaller than the angle 40-7()0 of the conventional guide member, for example, 10-4o, preferably 15-3[] It is about ”.

In the apparatus shown in FIGS. 2 and 3, similarly to the apparatus shown in FIG.
(30b) and C may also be provided with a retaining cylinder fA.

FIG. 4 is a schematic diagram of main parts showing another example of the present invention. In this example, similar to the apparatus shown in FIG. 1, the insulating g? i (91) and a pair of guide members (40a) (40b) are provided.

The nip roll (l Ia) (llb) side of the pair of guide members (40a) (40b) is formed into a parallel flat plate shape. That is, each guide member (40a) (4
(421+ ).

In such a device, the guide members (40a) (40b)
In the parallel flat plate portions (42a) (42b) of 6) can be folded under tension without wrinkles.

In addition, in the apparatus shown in FIG. 4, the number of heat insulation cylinders (9) is not necessarily 7, and the pair of guide members (40a)
The upper end of (40b) may be located near the expansion start part of the cylindrical film (6), similar to the apparatus shown in FIGS. 2 and 3. Further, the pair of guide members (40a)
(401)) nip roll (11a) (Ilb)
The sides are not limited to parallel plate shapes. For example, if the angle between the pair of guide members (40a) (40b) on the nip roll (lla) (llb) side, that is, on the guide terminal end side, is smaller than the slope portions (41a) (41b) on the die (4) side. good.

In order to prevent wrinkles from forming, a pair of guide members (40
a) It is preferable that the length of the guide terminal end side with the smaller angle (40b) is 20 cm or more.

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

Among these liquid crystalline polymers, aromatic liquid crystalline polymers, especially fully aromatic polyesters and fully aromatic polyesteramides, have excellent mechanical strength, mechanical properties, judicial stability, chemical resistance, heat resistance, and electrical properties. is preferred.

The molecular weight of a liquid crystalline polymer cannot be determined unconditionally since it varies depending on its type, but in the case of a suitable fully aromatic polyester, for example, the weight average molecular weight is about 2,000 m.
~200,000, preferably l,t about 10,00
0 to 50,000, more preferably about 20,000 to
There are 25,000 te. Further, the molecular weight of suitable fully aromatic polyesteramides is, for example, about 5.000 to 50.0
00, preferably about 10,000 to 30,000. J is preferably 115,000 to 17,000.

In producing the films of the invention, liquid crystalline polymers can be used alone or as a polymer composition. The polymer composition includes other polymers that form an anisotropic melt phase; thermoplastic resins that do not form an anisotropic melt phase; thermosetting resins; plasticizers, antioxidants, ultraviolet absorbers, antistatic agents, Additives such as flame retardants, colorants, blowing agents, crosslinking agents, lubricants; fillers such as inorganic fibers, whiskers, calcium carbonate, highly dispersed silicic acid, alumina, aluminum hydroxide, talcum powder, mica, barium sulfate, etc. may also be included. In the polymer composition, the liquid crystalline polymer is contained in an amount of at least 50% by weight ff196, preferably at least 80% by weight.

The film obtained as described above is subjected to heat treatment, if necessary. This heat treatment is performed under tension of the film.
Or it can be performed without tension. The heat treatment is carried out in an appropriate atmosphere such as air, nitrogen, or vacuum atmosphere for 7 days.
It can be carried out at a temperature of about 0 to 300''C.The temperature history cycle, heat treatment time, tension, etc. of the heat treatment can be set depending on the type of film and the required physical properties of the film.

Furthermore, the liquid crystalline polymer film may be subjected to surface treatment such as corona discharge treatment.

The thickness of the liquid crystalline polymer film is not particularly limited, but
Usually, it is 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 packaging films, photographic films, films for recording bodies such as magnetic recording tapes, and electrically insulating films.

[Effects of the Invention] The manufacturing apparatus and manufacturing method of the present invention can form a uniform cylindrical film without uneven thickness, can stably and uniformly stretch the cylindrical film, and can obtain a wrinkle-free liquid crystal polymer film. be able to.

[Examples] The present invention will be described in more detail below based on Examples.

Example 1 A pellet of a liquid crystalline polymer (manufactured by Polyplastic f#, trade name Vectra A900) consisting of polynisdel composed of the following repeating units [11 and [1] was heated in advance at a temperature of 150°C for dry,
Using an apparatus as shown in FIG. 1, it was extruded downward and stretched under the following conditions, and was taken off while being folded with nip rolls.

Extrusion direction: downward extrusion
Temperature: 280℃ Diameter of circular slit:
50mm Lip clearance = 1゜0■ Blow ratio (Dtd): 5.0 times Draft ratio (Dad): 6.0 times Expansion start part of cylindrical film: 25 cm below the die Inner diameter and length of heat insulation cylinder : 27cllφ Example 2 As shown in FIG. 2, the liquid crystal display was heated in the same manner as in Example 1, except that no heat insulating cylinder was used and the distance between the expansion start part of the cylindrical film and the upper end of the pair of guide plates was set to 0 cm. A polymer film was obtained.

Example 3 As shown in Fig. 3, a heat insulating tube was not used (the distance between the expansion start part of the cylindrical film and the upper end of the pair of guide plates was 5C11, and the angle of the pair of guide plates was 20°). A liquid crystalline polymer film was obtained in the same manner as in Example 1 except that.

Example 4 As shown in Fig. 4, in place of the pair of guide plates in Example 1, an inclined part (length 60 cm, angle 50°) on the die side and a parallel flat plate part (length 15 cm) on the nip roll side were used. ) A liquid crystalline polymer film was obtained in the same manner as in Example 1 except for using a pair of guide members composed of the following.

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

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

Extrusion direction: Upward extrusion Temperature: 280℃ Lip clearance: 1.
Omm Blow ratio (Dtd): 3.0 times Draft ratio (Dad): 12.0 times Film formability was evaluated based on the following criteria.

Excellent wrinkles: No wrinkles: No wrinkles: A lot of wrinkles Excellent bubble expansion: Can apply enough air pressure: Slightly poor expansion: Can maintain the specified air pressure The table shows the film formability results in which the film can be expanded only for a short time and the bubbles burst.

As is clear from the table, the films of each example were free from wrinkles and could be stretched uniformly and stably.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing an apparatus and method for manufacturing a liquid crystalline polymer film which is an example of the present invention, FIG. 2 is a schematic diagram of a main part showing another example of the present invention, and FIG. FIG. 4 is a schematic diagram of main parts showing another example of the present invention. (3) Extruder, (4) Inflation die, (5) Annular slit, (6) Cylindrical film, (7a) Gas supply path, (9)・・・Thermos cylinder, (10a) (lob) (20a) (20b)
(30a) (30b) (40a) (40b)・
...Guide member, (11a) (1lb) - Nip roll, (lea)
(16b)...Liquid crystalline polymer film patent applicant Daicel Chemical Industries, Ltd. Agent Patent attorney Hoe 1) Mitsuru Life Figure 4

Claims (1)

[Claims] 1. An annular slit through which a liquid crystalline polymer forming an anisotropic melt is extruded, and a gas supply path through which gas is pressurized into the hollow part of the cylindrical film extruded from the annular slit are formed. The device has an inflation die, a guide member that guides the opposing surfaces of the cylindrical film expanded by pressurizing gas while bringing them close to each other, and a take-up machine that folds and takes off the cylindrical film guided by the guide member. and the annular slit of the die faces downward,
A manufacturing apparatus for a liquid crystal polymer film, wherein a heat-retaining cylinder for keeping the cylindrical film warm is disposed between an expansion start part of the expanded cylindrical film and the guide member. 2. An inflation die formed with an annular slit through which a liquid crystalline polymer forming an anisotropic melt is extruded, and a gas supply path for injecting gas into the hollow part of the cylindrical film extruded from the annular slit; A device comprising a guide member that guides a cylindrical film expanded by pressurizing gas while bringing opposing surfaces close to each other, and a take-up machine that folds and takes over the cylindrical film guided by the guide member, the device comprising: With the slit facing downward,
A manufacturing apparatus for a liquid crystalline polymer film, wherein the guide member is disposed between the vicinity of the expansion start part and the folding part of the expanded cylindrical film. 3. A liquid crystalline polymer forming an anisotropic melt is melted and extruded downward through an annular slit, and the resulting cylindrical film is stretched in the take-up direction and the width direction perpendicular to the take-up direction to form a stretched cylinder. A method for producing a liquid crystalline polymer film, which comprises folding a shaped film while keeping it warm with the heat-insulating tube according to claim 1 or while guiding it with the guide member according to claim 2.