JP2003251675A - Method and apparatus for manufacturing multilayered film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a multilayered film by which thickness of the multilayered film can be efficiently controlled to a thickness with good handling properties while optical characteristics are kept and the film can be efficiently produced, and an apparatus for manufacturing it. <P>SOLUTION: The method for manufacturing the multilayered film in which at least eleven layers of layers A comprising a resin A and layers B comprising a resin B are laminated and at least one of outermost layers is a thick film layer and layers except the thick film layer are thin film layers, is characterized in that the resin A and the resin B are separately melted in extruders and the melted resins are respectively introduced into flow paths in multilayered feed blocks to form multilayered melted thin film layers, and at least one melted resin between the melted resin A and the melted resin B is made to branch from the melted resins introduced into the multilayered fed blocks and is joined to the outside of the multilayered melted thin film layers through a flow path for the outermost layer and is extruded into a sheet in the multilayered direction of the layers A and the layers B in the thickness direction from a successive die, and then, the film is cooled and solidified on a casting drum to form an undrawn film and this undrawn film is drawn in at least one direction of the longitudinal and transverse directions. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method and an apparatus for producing a multilayer film. More specifically, the present invention relates to a method and apparatus for manufacturing a multilayer film in which a thick film layer is provided as an outer layer of a multilayer film having 11 or more layers laminated, capable of selectively reflecting or transmitting light in an arbitrary wavelength band, and The present invention relates to a method and an apparatus for producing a multilayer film, which can efficiently produce a multilayer film having a good handling property without being affected by the optical characteristics of the above.

[0002]

2. Description of the Related Art A multi-layer film is an optical interference film that selectively reflects or transmits light of a specific wavelength due to structural optical interference between layers having a high refractive index and a low refractive index, for example. Become. By making the wavelength region of light that is selectively reflected or transmitted in the visible light region, such laminated films are increasingly used as reflective polarizing plates, color-developing films, metallic luster films, and reflection mirror films. Also, if you selectively block the ultraviolet rays,
It can be used as an agricultural film for insect repellent. Also, if you selectively cut the near infrared rays, use it as a window covering film for cutting solar radiation, or as a near infrared cut film to prevent malfunction of peripheral devices on the image display panel surface such as plasma display. You can Further, the multi-layer film is promising as a hologram application in which multi-layer films for selectively transmitting the respective hues of R, G and B are selectively and appropriately transmitted in order to project an image on a show window.

Such a multilayer film is disclosed in Japanese Patent Laid-Open No. 2000-2000.
No. 329935 is proposed. But,
In a multilayer film in which the thickness of each layer is substantially uniform, there is a problem in that the total thickness of the multilayer film is determined depending on the wavelength region to be reflected or transmitted. For example, in order to substantially block near infrared rays and ultraviolet rays, a reflection strength of about 200 layers is sufficient, but the total thickness of the multilayer film is 5
Since the thickness is about 30 μm, the handling property is poor, and there is a problem that air is mixed in when it is attached to a window, a light bulb, or a display. A method of simply increasing the number of layers to increase the total thickness is also conceivable, but the multi-layer feed block becomes large in size as the number of layers increases, and there is a problem in that its production is technically difficult and enormous in cost.

[0004]

SUMMARY OF THE INVENTION The object of the present invention is to solve the above-mentioned problems and to efficiently control the thickness of a multilayer film to a thickness with good handleability while maintaining the optical characteristics, and to efficiently produce the film. It is to provide a method and an apparatus for producing a multilayer film.

[0005]

According to the present invention, (1) 11 or more layers of A layer made of resin A and B layer made of resin B are laminated, and at least one of the outermost layers is formed. Is a thick film layer, and the layers other than the thick film layer are thin film layers. A method for producing a multilayer film, wherein resin A and resin B are separately melted by an extruder, and each molten resin is fed into a multilayer feed. A multilayer molten thin film layer is formed by guiding the molten resin into at least one of the molten resin A and the molten resin B, which is guided to the flow path in the block, and is branched from the molten resin leading to the multilayer feed block through the outermost layer flow path. The layers are joined to the outside of the layer, and extruded into a sheet form from the subsequent die in a direction in which the A layer and the B layer are multilayered in the thickness direction, and then cooled and solidified by a casting drum to obtain an unstretched film. Direction and lateral It can be achieved by the method for producing a multilayer film characterized in that stretching in Kutomo one direction.

Further, as a further preferred embodiment of the present invention,
(2) The method for producing a multilayer film according to (1), wherein both outermost layers are thick film layers made of resin A or resin B.
(3) One of the outermost layers is a thick film layer made of resin A, and the other layer is a thick film layer made of resin B, (4) The method for producing a multilayer film, (4) Outermost layer The flow channel has a structure in which the cross section changes from circular to rectangular, and a distribution pin that partially closes the flow channel is inserted in the rectangular portion, and the flow rate of the molten resin is adjusted by the flow channel opening of the pin. (1) The thickness of the thick film layer of the unstretched film is in the range of 1 to 100 μm, and the thickness of the thin film layer is in the range of 0.01 to 0.5 μm. (1) The method for producing a multilayer film according to any one of (3), (6) after each of the molten resin A and the molten resin B introduced into the multilayer feed block is branched into multiple layers by pores, Partitioned with parallel plates so that branched molten resin A and molten resin B flow alternately. The multilayer film according to any one of (1) to (3), wherein the thin film layer is formed by alternately guiding the resin A and the resin B to the confluent portion in the multilayer feed block, and forming a thin film layer. The method for producing a multilayer film according to any one of claims 1 to 3, wherein (7) an inner deckle that closes pores and / or confluences is used to control the number of thin film layers. (8) The method for producing a multilayer film according to any one of claims 1 to 7, wherein the thickness of the thin film layer is gradually changed by giving a temperature distribution to the multilayer feed block, (9) A constituting an unstretched film. The method for producing a multilayer film according to (1), wherein the difference between the refractive index in the in-plane direction of the layer and the refractive index in the in-plane direction of the B layer is 0.005 or more, (10) stretching in at least one direction In-plane bending of layer A that composes the film The difference between the refractive index and the in-plane refractive index of the B layer is 0.005 or more (the manufacturing method of the multilayer film described in 19, (11) the resin A contains polyethylene-2,6-naphthalate as a main component ( 1) ~
The method for producing a multilayer film according to any one of (10),
(12) The method for producing a multilayer film according to any one of claims 1 to 10, wherein the resin B contains a mixture of polyethylene-2,6-naphthalate and polyethylene terephthalate as a main component, and (13) the resin B has a melting point of 210 to 245. A polyethylene terephthalate copolymer having a temperature of ℃ as a main component.
10. The method for producing a multilayer film according to any of 10,
4) The method for producing a multilayer film described in (13), wherein the copolymerization component of the polyethylene terephthalate copolymer is ethylene isophthalate.

Further, the object of the present invention is (15) 11 or more layers of A layer made of resin A and B layer made of resin B are laminated, and at least one of the outermost layers is a thick film layer. A multilayer film manufacturing apparatus in which layers other than the membrane layer are thin film layers, wherein resin A and resin B are separately melted by an extruder, and each molten resin is introduced into a flow path in a multilayer feed block to perform multilayer melting. As a thin film layer, separately, at least one of the molten resin A and the molten resin B is branched from the molten resin that leads to the multilayer feed block, and is joined to the outside of the multilayer molten thin film layer through the outermost layer flow path. This can be achieved by the multilayer feedblock used in the method for producing a multilayer film according to item (1).

As a further preferred embodiment of the present invention,
(16) A structure in which the cross section of the outermost layer channel changes from a circular shape to a rectangular shape, and a distribution pin that partially closes the channel is inserted in the rectangular portion, and the resin is opened at the opening degree of the pin. The multi-layer feed block described in (15) for adjusting the flow rate of (15), (17) a means for providing a temperature distribution in the multi-layer feed block for gradually changing the thickness of the thin film layer is provided in (15) or (16). Mention may be made of the described multilayer feedblock.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below with reference to the drawings.

FIG. 1 is a plan view of a multilayer feedblock illustrating one embodiment of the present invention. 2 is a side view of a multi-layer feed block exemplifying one embodiment of the present invention, and FIG. 3 is a molten resin A for layer A in the portion C of FIG.
FIG. 4 is a perspective view of a portion branched by a fine hole, and FIG. 4 is a perspective view showing a flat channel in the portion C in which the resin B is branched to alternately overlap the A layer and the B layer. FIG. 5 is a schematic diagram showing the arrangement of each device when the molten resin in the multilayer feed block is extruded from a die and cooled by a casting drum to form an unstretched film.

1 to 4, 1 is a multi-layer feed block, 2 is a distribution pin, 3 is a manifold, 4 is a post-merging manifold, 5 is a rectangular cross-section conduit, and 6 is a conduit.
Is an outermost layer (surface layer) of A-layer resin conduit, 7 is a thin-film portion of A-layer resin conduit, 8 is a B-layer resin conduit, 9 is a pore portion, 10 is a parallel plate, and 11 is a flat plate partitioned by parallel plates. A flow path, 12 is an inner deckle, a is a flow direction of the molten resin A forming the A layer, and b is a flow direction of the molten resin B forming the B layer.

In FIG. 5, 21 is a conduit of molten resin A to the multi-layer feed block, 22 is a conduit of molten resin B to the multi-layer feed block, 23 is an extrusion die, 24 is a sheet extruded from the die, 25 Is a casting drum and 26 is an unstretched film.

In the present invention, the thin film layer in which the A layer and the B layer are alternately laminated can be laminated as follows. Ie conduit 2
The molten resin A for the A layer introduced into the feed block 1 at 1 is once spread in the width direction in a manifold (not shown) via the conduit 7, and is partitioned by the parallel plate 10 through the pores 9 arranged in a line. It reaches the flat flow path 11. On the other hand, B
The molten resin B for layers passes from the conduit 22 through the conduit 8 and is once widened in the width direction by the manifold 3 to reach the flat flow path 11 partitioned by the parallel plates 10. In the flat flow path 11 partitioned by the parallel plate 10 (gap between each member of the parallel plate 10), the resin A and the resin B are already alternately arranged, and then the flat flow path 11 outlet partitioned by the parallel plate Merging manifold 4
The melted resins of the A layer and the B layer are alternately laminated in a fluidized state by merging in the void portions.

A feature of the present invention is that the film is inevitably thinned only by laminating the thin film portions and the film becomes difficult to handle. Therefore, a thick film layer is provided as the outermost layer (hereinafter, also referred to as "surface layer"). is there. That is, the conduit 21
The molten resin A that has entered further is temporarily transferred to the conduit 7 through the T-shaped conduit.
(Conduit toward thin film layer) and conduit 6 (conduit toward surface thick film layer), and the conduit toward the surface layer is branched by T-shaped conduit into conduits 6 toward both surface layers, and then distribution pin 2 A thick film layer can be provided on the surface layer by rejoining with the molten resin in the thin film portion in the vicinity of.

The shape of the distribution pin 2 can be the shape known and used conventionally,
For example, a shape in which a circular cross section is cut out as shown in FIG. 8 can be exemplified to partially close the rectangular conduit portion 5. Also, by rotating this pin, you can change the cross-sectional area of resin passage,
As a result, the flow rates of the thin film portion and the thick film portion can be adjusted, and the flow rates of the thick film layers can also be adjusted, so that a multilayer laminated film having a wide thickness band can be manufactured. On the other hand, it is possible to provide a thick film layer by changing the width of the pores 9 described later, but in this case, it is necessary to have a feed block in which the width of the pores is different depending on the required thickness, which is economical. It is a disadvantage.

In the present invention, FIG. 1 and FIG. 2 exemplify the feed block in which the molten resin A for the A layer is branched, but the molten resin B for the B layer is also branched as necessary as shown in FIG. It is also possible to obtain the laminated structure shown in FIG. The reason for turning both resins on the surface is usually
The resin A to be applied to the surface layer has a high refractive index and a high stretching temperature. However, in general, this resin is often expensive, and if the thick film layer is formed only with the A layer resin, the unit price of the film increases, In some cases, it may be advantageous in terms of manufacturing cost to form the thick film layer with a relatively inexpensive B layer resin.

On the other hand, regarding the details of the merging portion of the thin film portion of the portion c, if the width of the pore 9 is too narrow, the flow rate of each layer reacts sensitively to the width dimension, so that highly precise processing is required, and conversely. If it is too wide, pressure will not build up in the pores and the flow rate of each layer tends to vary, so 0.2-2 mm is preferable, and 0.5-1 mm.
Is more preferable. The length of the pores is 5-25 mm because it cannot be processed if it is too long due to the electric discharge machining using a wire.
Is preferable, and 7-12 mm is more preferable. Also, if each pore is made to have substantially the same size, for example, if the temperature is controlled so that there is no temperature difference in the width direction of the feed block (isothermal state), a multilayer laminated film in which the thickness of each layer of the thin film part is uniform Can be formed, and conversely, when the thickness of each layer of the thin film portion is changed, it can be dealt with by providing a temperature distribution in the width direction of the feed block. Of course, it is also possible to change the thickness of each layer of the thin film portion by changing the width of each pore 9, and the range of changing the width dimension is preferably within the above-mentioned good range.

If the wall thickness of the parallel plate 10 is too thin, it will be easily damaged by maintenance, and it will be bent by the internal pressure of the resin during operation. If it is too thick, if the number of layers is increased, the width of the feed block becomes large and the size becomes large. 0.3-4m
m is preferable, and 0.5-2 mm is more preferable. The length of the parallel plate 10 is preferably 5 to 40 mm, and more preferably 10 to 20 mm, from the viewpoint of being less likely to be damaged and appropriately obtaining a pressure loss. The arrangement pitch of the parallel plates 10 is preferably matched with the width dimension of 9, and by incorporating it without steps, it is possible to form a good film without deterioration of resin retention.

As can be seen from the above, each of the parts constituting the feed block 1 requires high-precision processing, but has a weak structure in terms of strength.
US630 and SUS420 (J2) are suitable. If the resin flow surface of each block is finished to 0.6 S or more, a multilayer laminated film having no line defects can be formed.

The laminated state of the layers A and B in the present invention is as follows.
The total number of layers A and B is 11 or more, preferably 31 or more. If the number of layers is less than 11, the selective reflection due to multiple interference is small and a sufficient reflectance cannot be obtained.
The upper limit of the number of layers is preferably 301 from the viewpoint of productivity. Dedicated feed blocks may be prepared individually according to the number of layers of the multilayer laminated film, but in the case of the device of the present invention and a device for branching into multiple layers by the pores, the resin inlet of the pores may be selected according to the required number of layers. It is more advantageous in terms of cost to insert the inner deckle 12 that closes the layer to control the number of layers.

The thickness of each of the A layer and the B layer in the thin film portion is required to be 0.01 to 0.5 μm in order to selectively reflect light by optical interference between the layers.
Further, the individual thickness of the thick film portion is preferably 1 to 100 μm, and if it is smaller than this, it is necessary to adjust the flow rate opening at the pin 2 to be extremely narrow, and it is difficult to mechanically adjust the resin. The flow rate balance with the flow rate is likely to collapse. On the contrary, a range larger than this is technically possible, but is not currently required as a multilayer film.

Each of the feed block diagrams of FIGS. 1 to 4 illustrates one embodiment, in which the pores 9 and the parallel plates 10 merge vertically, but the path difference of the resin is different. The resin B may be joined at an angle with a certain angle in order to average the residence time due to
However, similar to the case of the resin A, it is possible to provide the pores 9 and branch at the pores.

The multilayer film in the present invention is, for example,
A polymer which mainly forms polyethylene-2,6-naphthalate and which forms an A layer and a polymer which forms a B layer are laminated by a feed block illustrated in the drawing, and the resulting die is developed while maintaining the laminated state. The sheet extruded from the die is cooled and solidified by a casting drum to be an unstretched film. The unstretched film is stretched in a longitudinal and / or transverse direction at a predetermined temperature, heat-treated at a predetermined temperature, optionally heat-relaxed, and wound.

By the way, the multilayer film of the present invention is stretched in at least one direction, and preferably biaxially stretched. However, in the present invention, since a polymer having a high refractive index is selected for the A layer side, the stretching temperature is Glass transition point of resin of layer A (T
It is preferable to carry out in the range of g) to (Tg + 50) ° C. In the case of uniaxial stretching, the stretching ratio is 2 to 10 times, and the stretching direction may be vertical or horizontal. In the case of biaxial stretching, the area magnification is 5 to 25 times. The larger the draw ratio, the smaller the variation in the plane direction in the individual layers of the A layer and the B layer becomes due to the thinning due to the stretching, and
It is preferable because the light interference of the multilayer film becomes uniform in the surface direction. As the stretching method, sequential biaxial stretching, simultaneous biaxial stretching,
Known stretching methods such as tubular stretching and inflation stretching are possible, but sequential biaxial stretching is preferable in terms of productivity and quality.

The stretched film is preferably stabilized by heat treatment for thermal stabilization. The temperature of the heat treatment is (melting point of resin constituting layer B-3
0) higher than ℃ (melting point of resin constituting layer A-30) ℃
It is preferably lower.

Furthermore, the multilayer polyester film of the present invention is stretched because the glass transition point of the polymer forming the A layer is usually higher than that of the polymer forming the B layer when the B layer is present in either of the both end layers. Therefore, the temperature cannot be raised to the stretching temperature required for stretching the A layer when heated with rolls, etc., or the temperature cannot be raised to prevent the B layer on the surface from melting during heat setting. In some cases, problems such as insufficient physical stability may occur. On the other hand, when the A layer is at both end layers, the thermally unstable B layer is located at the inner layer, so that it can be produced at a sufficient stretching temperature or heat setting temperature. Those located in layers are preferred. Incidentally, the both end layers referred to in the present invention are the outermost layers in the direction perpendicular to the plane direction of the multilayer film.

Further, a step of applying a coating liquid and drying the same may be provided for the purpose of, for example, the step of producing the multilayer film of the present invention, or the purpose of imparting functionality to the surface of the film after the production.

In the present invention, the resin A constituting the layer A is a thermoplastic resin containing a stretchable polymer as a main component, for example, an aromatic compound such as polyethylene terephthalate, polyethylene-2,6-naphthalate and polybutylene terephthalate. Group polyesters, polyolefins such as polyethylene, polypropylene, polyvinyls such as polystyrene, polyamides such as nylon 6 (polycaprolactam), nylon 66 (poly (hexamethylenediamine-co-adipic acid)), such as bisphenol A polycarbonate A homopolymer such as aromatic polycarbonate or polysulfone or a resin containing a copolymer thereof as a main component can be used.

Among the above-mentioned thermoplastic resins, aromatic polyesters, polyolefins, which are capable of molecular orientation by stretching,
Polyamide is preferable, and polyethylene-2,6-naphthalate, which has excellent optical, mechanical and thermal properties when the molecules are biaxially oriented, is particularly preferable.

In the present invention, when a resin mainly composed of polyethylene-2,6-naphthalate is used as the resin A constituting the layer A, a copolymerized polyethylene-2,6-containing mainly ethylene-2,6-naphthalate units is used. A composition mainly containing naphthalate or polyethylene-2,6-naphthalate can be used. The term "mainly" means that the proportion of ethylene-2,6-naphthalate units in the copolymer or composition accounts for 85 mol% or more based on all components. When a copolymer is used, its copolymerization component is preferably 15 mol% or less, more preferably 2 mol% or less. The copolymerization component may be a dicarboxylic acid component or a glycol component, and examples of the dicarboxylic acid component include aromatic dicarumbonic acid such as isophthalic acid, phthalic acid and naphthalenedicarboxylic acid; adipic acid,
Aliphatic dicarboxylic acids such as azelaic acid, sebacic acid, decanedicarboxylic acid and the like; alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid and the like, and examples of the glycol component include aliphatic diols such as butanediol and hexanediol. Alicyclic diols such as cyclohexanedimethanol can be mentioned.

The resin B in the present invention is a thermoplastic resin having a refractive index different from that of the thermoplastic resin constituting the A layer, and has a refractive index lower than that of the resin A by 0.005 or more, more preferably 0.02 or more. Low thermoplastic resins Low resins can be mentioned. The term "refractive index" as used herein refers to the in-plane refractive index of a sheet-shaped or film-shaped resin.

In the present invention, when polyethylene-2,6-naphthalate is used as the resin A constituting the layer A, the resin B is preferably a resin having a refractive index lower than that of polyethylene-2,6-naphthalate. It is preferable that the resin has a refractive index lower than that of polyethylene-2,6-naphthalate by 0.005 or more, and particularly a refractive index of 0.02.
It is preferable that the resin is low. As such a thermoplastic resin, the following three types (1) to (3) can be preferably mentioned.

(1) A mixture of polyethylene-2,6-naphthalate and polyethylene terephthalate (2) Syndiotactic polystyrene (3) A polyethylene terephthalate copolymer having a melting point of 210 ° C to 245 ° C.

Among these, the B layer is polyethylene-
A mixture of 2,6-naphthalate and polyethylene terephthalate or a mixture of syndiotactic polystyrene is preferable, and a mixture of the above-mentioned B layer is particularly preferable because the refractive index of the B layer can be easily changed. Below, the polymer constituting the layer B in the present invention is
(1) The case of a mixture of polyethylene-2,6-naphthalate and polyethylene terephthalate will be described in detail.

When the polymer constituting the layer B in the present invention is a mixture of polyethylene-2,6-naphthalate and polyethylene terephthalate, the mixing ratio of the two is 5:95 to 95: 5, especially by weight. 20: 80 ~
It is preferably in the range of 80:20. In the mixing ratio, the ratio of polyethylene terephthalate is 5% by weight.
When the proportion of polyethylene-2,6-naphthalate exceeds 95% by weight, the difference in refractive index from the layer A tends to be insufficient, while when the proportion of polyethylene terephthalate exceeds 95% by weight or polyethylene-2. When the proportion of 6-naphthalate is less than 5% by weight, the difference in melt viscosity between the layer A and the layer A becomes excessively large, and it becomes extremely difficult to maintain the multilayered state.

By the way, the refractive index of the B layer can be adjusted by changing the mixing ratio of polyethylene terephthalate and polyethylene-2,6-naphthalate, so it is necessary to prepare various polymers for adjusting the reflectance. There is no. In other words, there is an advantage that a multilayer laminated stretched film having various reflectances can be easily obtained only by adjusting the mixing ratio in the mixture. In addition, when the polymer of the layer B is copolymerized, it becomes low in crystallinity, and therefore a special extruder or dryer may be required for extruding the molten polymer. However, in the present invention, since it is a mixture, there is an advantage that the decrease in crystallinity is small and the above-mentioned special equipment is not required.

The polyethylene terephthalate and polyethylene-2,6-naphthalate in the mixture constituting the layer B will be described in more detail.

The polyethylene-2,6-naphthalate in the mixture is polyethylene-2,6-naphthalate homopolymer, or at least 80 mol%, preferably 90 mol% or more of all repeating units are ethylene-2,6-. It is a copolymer occupied by naphthalate. Among these, the above homopolymers are preferable. Examples of the copolymerization component that constitutes the above copolymer include other aromatic carboxylic acids such as terephthalic acid, isophthalic acid, and 2,7-naphthalenedicarboxylic acid; adipic acid, azelaic acid, sebacic acid, decanedicarboxylic acid, and the like. Such as aliphatic dicarboxylic acids; acid components such as alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid; fatty acid diols such as butanediol and hexanediol; glycol components such as alicyclic diols such as cyclohexanedimethanol. it can.

The polyethylene terephthalate in the mixture is a polyethylene terephthalate homopolymer or a copolymer in which at least 80 mol%, preferably 90 mol% or more of all repeating units are occupied by ethylene terephthalate. Among these, the above homopolymers are preferable. Examples of the copolymerization component constituting the above-mentioned copolymer include other aromatic carboxylic acids such as isophthalic acid and 2,7-naphthalenedicarboxylic acid; aliphatic compounds such as adipic acid, azelaic acid, sebacic acid and decanedicarboxylic acid. Dicarboxylic acids; aliphatic diols such as cyclohexanedicarboxylic acid; glycol components such as alicyclic diols such as cyclohexanedimethanol. Among these copolymers, the copolymer of isophthalic acid is preferred.

By the way, the melting point of the mixture constituting the B layer is lower than the melting point of the original polymer, but two peaks derived from each polymer are formed. Among the melting point peaks of the mixture forming these B layers, the higher peak temperature is 220 ° C to 265 ° C, and further 240 to 26 ° C.
Those in the range of 0 ° C. are preferable. Further, the temperature difference between the melting point of the polymer forming the A layer and the higher melting point peak of the mixture forming the B layer is preferably at least 10 ° C. and more preferably at least 20 ° C. If this difference in melting point is at least 10 ° C., the difference in orientation due to heat treatment tends to increase,
Easy to make a difference in refractive index.

In the present invention, the stretched film is
For thermal stabilization, it is preferable to perform a heat treatment (heat setting treatment), and when a mixture of polyethylene-2,6-naphthalate and polyethylene terephthalate is used as the polymer constituting the layer B, the layer A is used. Based on the melting point (TmA) of the polymer of (TmA-60) ° C ~
It is preferable to perform heat treatment at a temperature in the range of (TmA-10) ° C.

In the present invention, at least one of the polymers constituting the layer A or the layer B has an average particle size of preferably 0.01 to 2 in order to improve the film winding property.
μm, more preferably 0.05 to 1 μm, most preferably 0.1 to 0.3 μm, preferably 0.001 to 0.5% by weight, more preferably 0.0 to 0.5% by weight of the inert particles.
It is contained at a rate of 05 to 0.2% by weight. If the average particle size of the inert particles is less than 0.01 μm or the content thereof is less than 0.001% by weight, the improvement of the film winding property tends to be insufficient, while the average particle size of the inert particles exceeds 2 μm, or If the content exceeds 0.5% by weight, the deterioration of the optical characteristics due to the particles is likely to be remarkable, and the light transmittance of the entire film may decrease. The light transmittance is preferably 70% or more, and if it is lower than this, the performance is insufficient for optical applications.

Examples of such inert particles include inorganic inert particles such as silica, alumina, calcium carbonate, calcium phosphate, kaolin and talc, organic inert materials such as silicone, crosslinked polystyrene and styrene-divinylbenzene copolymer. Active particles can be mentioned.

[0044]

EXAMPLES The present invention will be further described below with reference to examples. The physical properties in the examples were measured by the following methods.

(1) Thickness samples of each layer are cut into triangles and fixed in embedding capsules,
Embed with epoxy resin. Then, after embedding the sample into a thin film section with a thickness of 50 nm in a cross section parallel to the longitudinal direction with a microtome (ULTRACUT-S), it was observed with a transmission electron microscope at 100 kv of accelerated electrons.
The thickness of each layer was measured from the photograph projected, and the thicknesses of the A layer and the B layer were measured.

(2) Reflectance Using a spectrophotometer MPC-3100 manufactured by Shimadzu Corporation, the relative specular reflectance with respect to the aluminum vapor-deposited mirror at each wavelength is measured in the wavelength range of 350 to 2100 nm. The maximum reflectance among the measured reflectance is the maximum reflectance.

(3) Peak inverse value width The same measurement as the wavelength maximum reflectance is carried out, and the values on the short wavelength side and the long wavelength side of the wavelength which becomes the half maximum width of the maximum reflectance are respectively defined on the short wavelength side and the long wavelength side. The wavelength range was used.

(4) Sample with a refractive index of sodium D line (589 nm) as a light source, methylene iodide as a mount solution, and an Abbe refractometer equipped with a polarizing plate at 25 ° C. and 65% RH. The refractive index (nMD) in the longitudinal direction and the refractive index (nTD) in the width direction of the sample were measured, and the average value of nMD and nTD was defined as the in-plane refractive index (nAve). However, in the stretched film of the present invention, two lines corresponding to resin A and resin B are visible, so the high refractive index side is the A resin and the low refractive side is the B resin.

The samples were prepared as follows.

(Refractive Index of Unstretched Sheet of Resin A) Resin A was applied to both the A layer extruder and the B layer extruder used in each example.
After being supplied and melted, the melted resin A was introduced into the multi-layer feed block used in each example, the polymer was branched into multi-layers in the multi-layer feed block, and then the layers A were joined at the confluence in the multi-layer feed block. Alternately laminated, and further join the A resin to the outer layer of the laminated molten resin and guide it to the die,
An unstretched sheet in which the layers A were laminated was produced by casting on a casting drum. The refractive index of this sheet in the in-plane direction was measured and used as the refractive index of the unstretched sheet of resin A.

(Refractive index of unstretched sheet and stretched sheet of resin B) Refractive index of the above resin A except that the resin B was supplied to both the extruder for layer A and the extruder for layer B used in each example. In the same manner as the measurement, the refractive index of the unstretched sheet of resin B was measured.

(Refractive Index of Stretched Film) The in-plane refractive index of the stretched film obtained in each Example was measured.

(5) Glass transition temperature (Tg) 10 mg of a sample was used as a DSC device (Therm, manufactured by DuPont).
al Analyst 2000 type differential calorimeter), melted at a temperature of 300 ° C. for 5 minutes, and then rapidly cooled in liquid nitrogen. The temperature of this quenched sample is raised at 10 ° C./min, and the glass transition point Tg is measured.

(6) Melting point (Tm) A 10 mg sample was used as a DSC device (Therm, manufactured by DuPont).
al Analyst 2000 type differential calorimeter), melted at a temperature of 300 ° C. for 5 minutes, and then rapidly cooled in liquid nitrogen. The temperature of this quenched sample was raised at 10 ° C./min, and the melting point peak temperature was measured.

[Embodiment 1] First, in the apparatus shown in FIGS.
The number of pores 9 in the A layer is 100 and the width is 0.70.
mm, depth 17 mm, the number of flat flow paths 11 is 100
And the depth is 17 mm, the number of the flat flow passages 11 of the B layer is 101, the width is 0.70 mm, and the depth is 17 mm.
Insert the inner deckle 12 made of aluminum into a multi-layer feed block made of US630, and make A layer of the thin film portion 30 layers,
The B layer was 31 layers. Further, the thick film portion was configured such that the layer A had one layer on each end side.

Resin A has an intrinsic viscosity (orthochlorophenol, 35 ° C.) of 0.62 dl / g polyethylene-2,6-naphthalate (PEN), and Resin B has an intrinsic viscosity (orthochlorophenol, 35 ° C.). 0.63dl /
g polyethylene terephthalate (PET) was prepared. Then, the spherical silica particles (average particle size:
0.12 μm, ratio of major axis to minor axis: 1.02, average deviation of particle diameter: 0.1) 0.11 wt% was added as resin for layer A, and PEN and PET containing no inactive particles 5
The mixture for the weight ratio of 0:50 was prepared as the resin for layer B.

The resin for the layer A was dried at 160 ° C. for 3 hours, and the mixed resin for the layer B was dried at 160 ° C. for 3 hours, and then supplied to the extruder for layer A and the extruder for layer B to melt and melt. The resin A and the resin B are introduced into the multi-layer feed block, the polymer of the A layer is first branched into the thick film portion and the thin film portion in the multi-layer feed block, and the A layer resin toward the thick film portion is further divided at both ends. The layer A resin that branches into two layers and the remaining thin layer part is branched into 30 layers through the pores 9, while the polymer of layer B is branched into 31 layers through the flat flow path 11, and then the multilayer feed is performed. The A layer and B layer of the thin film portion are alternately laminated at the confluence portion in the block, and while maintaining the laminated state of the 61 layers, the A layer resin toward both ends is recombined while adjusting the flow rate with the pin 2. Guide it to the die and cast it on the casting drum to stack the layers A and B Created a laminated unstretched sheet was total 63 layers.

This unstretched laminated sheet was stretched 3.2 times in the longitudinal direction at a temperature of 150 ° C., further stretched 3.5 times in the transverse direction at a stretching temperature of 155 ° C., and heat-treated at 230 ° C. for 3 seconds. Fixed treatment was performed. Table 1 shows the physical properties of the obtained multilayer film. The refractive index of the resin A, which was separately measured, was 1.647 for the unstretched sheet and 1.770 for the stretched film.
The refractive index of resin B (resin H) is 1.6 for an unstretched sheet.
12 and 1.651 for the stretched film.

[Examples 2 to 5] Multilayer films were produced in the same manner as in Examples except that the combination of the feed block, the number of layers, and the resin was changed as shown in Table 1, and ultraviolet rays and RGB rays were selectively emitted. The reflective property was obtained. Table 1 shows the results of measuring the physical properties of the obtained film.

[Example 6] A multilayer film was produced in the same manner as in Example 5 except that the temperature distribution was given in the width direction of the feed block, and a characteristic capable of cutting in the near infrared wavelength range was obtained. Table 1 shows the results of measuring the physical properties of the obtained film.

[0061]

[Table 1]

The resins for layers A and B shown in Table 1 are as follows.

Resin F: PEN added with 0.11 wt% of true spherical silica particles (average particle diameter: 0.12 μm, ratio of major axis to minor axis: 1.02, average deviation of particle diameter: 0.1) .

Resin G: True spherical silica particles (average particle size:
0.12 μm, ratio of major axis to minor axis: 1.02, average deviation of particle size: 0.1) PEN added at 0.11 wt% and PET containing no inert particles in a weight ratio of 70:30. A mixture. The refractive index of this resin is 1.
664 and 1.710 for the stretched film.

Resin H: PEN and P containing no inert particles
A mixture of ET in a weight ratio of 50:50.

Resin I: PET copolymer obtained by copolymerizing 12 mol% of isophthalic acid containing no inert particles. The refractive index of this resin was 1.590 for the unstretched sheet and 1.630 for the stretched film.

[0067]

According to the present invention, it is possible to control the thickness of a multilayer film to a thickness with good handleability while maintaining optical characteristics, and to efficiently produce a multilayer film.

[Brief description of drawings]

FIG. 1 is a plan view of a multi-layer feed block showing one embodiment of the present invention.

FIG. 2 is a side view of a multi-layer feedblock showing one embodiment of the present invention.

FIG. 3 is a perspective view of a portion of the portion C of FIG. 2 where the molten resin A for layer A is branched by pores.

FIG. 4 is a diagram illustrating a portion C of FIG.
It is the perspective view which showed the flat flow path which piles up a layer by turns.

FIG. 5 is a perspective view showing an arrangement of a multi-layer feed block, an extrusion die, a cooling drum, etc. in one embodiment of the present invention.

FIG. 6 is a plan view of a multilayer feedblock showing one embodiment of the present invention.

FIG. 7 is a diagram showing a thin film portion and a thick film portion of a multilayer laminated film.

FIG. 8 is a cross-sectional view showing the shape of a distribution pin in one embodiment of the present invention.

[Explanation of symbols]

1: Multi-layer feed block 2: Distribution pin 3: Manifold 4: Manifold after merging 5: Rectangular section conduit 6: Outermost surface layer A resin conduit 7: A layer resin conduit for thin film 8: B layer resin conduit 9: Pores 10: Parallel plate 11: Flat flow path partitioned by parallel plates 12: Inner deckle 21: Conduit of molten resin A to multi-layer feed block 22: Conduit of molten resin B to multi-layer feed block 23: Extrusion die 24: Sheet extruded from die 25: Casting drum 26: Unstretched film a: Flow direction of the molten resin A forming the A layer b: Flow direction of the molten resin B forming the B layer Part c: the part shown in the perspective view of [Fig. 4]

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 4F100 AK01A AK01B AK01C AK01D                       AK01E AK41A AK41B AK41C                       AK41D AK41E AK42B AK42D                       AK42E AL01B AL01D AL01E                       AL05B AL05D AL05E BA15                       BA25 EH03 GB90 JA04B                       JA04D JA04E JN06 JN08                       JN18A JN18B JN18C JN18D                       JN18E YY00B YY00D YY00E                 4F207 AA24 AG01 AG03 AR06 KA01                       KA17 KB26 KL83 KW41                 4F210 AA24 AG01 AG03 QC06 QG01                       QG15 QG18

Claims (17)

[Claims] 1. A layer made of resin A and B made of resin B
A method for producing a multilayer film in which 11 or more layers are laminated, at least one of the outermost layers is a thick film layer, and the layers other than the thick film layer are thin film layers. Melted with an extruder, and each molten resin is introduced into the flow path in the multilayer feed block to form a multilayer molten thin film layer, and separately, at least one of the molten resin A and the molten resin B is introduced into the multilayer feed block. And the outside of the multilayer melted thin film layer via the outermost layer flow path, and then extruded into a sheet shape from the die following that in which the layers A and B become multilayer in the thickness direction, and then cooled by a casting drum. A method for producing a multilayer film, which comprises solidifying into an unstretched film, and stretching the unstretched film in at least one of a longitudinal direction and a transverse direction. 2. The method for producing a multilayer film according to claim 1, wherein both outermost layers are thick film layers made of resin A or resin B. 3. The method for producing a multilayer film according to claim 1, wherein one of the outermost layers is a thick film layer made of a resin A, and the other layer is a thick film layer made of a resin B. 4. The outermost layer channel has a structure in which its cross section changes from a circular shape to a rectangular shape, and a distribution pin for partially closing the channel is inserted in the rectangular portion, and the flow path opening degree of the pin. The method for producing a multilayer film according to claim 1, wherein the flow rate of the molten resin is adjusted with. 5. The thick film layer of the unstretched film has a thickness of 1 to 1.
The thickness of the thin film layer is 0.01 to 0.
The method for producing a multilayer film according to claim 1, wherein the thickness is in the range of 5 μm. 6. A parallel plate in which molten resin A and molten resin B introduced into a multi-layer feed block are branched into multiple layers by pores, and then the branched molten resin A and molten resin B flow alternately. It is guided to a flat flow path partitioned by and is further guided to the confluence in the multilayer feed block. Resin A and resin B
The method for producing a multilayer film according to any one of claims 1 to 3, wherein the thin film layers are alternately laminated. 7. The method for producing a multilayer film according to claim 1, wherein an inner deckle that closes the pores and / or the confluence is used to control the number of thin film layers. 8. The method for producing a multilayer film according to claim 1, wherein the thickness of the thin film layer is gradually changed by giving a temperature distribution to the multilayer feed block. 9. The difference between the in-plane refractive index of layer A and the in-plane refractive index of layer B constituting the unstretched film is 0.005.
The method for producing a multilayer film according to claim 1, which is the above. 10. The difference between the in-plane refractive index of the layer A and the in-plane refractive index of the layer B constituting the stretched film stretched in at least one direction is 0.005 or more. The method for producing a multilayer film. 11. A resin A containing polyethylene-2,6-naphthalate as a main component, as claimed in any one of claims 1 to 10.
The method for producing a multilayer film according to item. 12. The method for producing a multilayer film according to claim 1, wherein the resin B contains a mixture of polyethylene-2,6-naphthalate and polyethylene terephthalate as a main component. 13. The method for producing a multilayer film according to claim 1, wherein the resin B is mainly composed of a polyethylene terephthalate copolymer having a melting point of 210 to 245 ° C. 14. The copolymerization component of a polyethylene terephthalate copolymer is ethylene isophthalate.
4. The method for producing a multilayer film according to item 3. 15. An A layer made of a resin A and a B layer made of a resin B are laminated in 11 layers or more, at least one of the outermost layers is a thick film layer, and the layers other than the thick film layer are thin film layers. A multilayer film manufacturing apparatus, in which resin A and resin B are separately melted by an extruder, each molten resin is introduced into a flow path in a multilayer feed block to form a multilayer molten thin film layer, and separately melted resin A and 2. The multilayer film according to claim 1, wherein at least one of the molten resins B is branched from the molten resin that leads to the multilayer feed block and is joined to the outside of the multilayer molten thin film layer through the outermost layer flow path. Multi-layer feed block used in the manufacturing method of. 16. A structure in which the cross-section of the outermost layer flow passage changes from a circular shape to a rectangular shape, and a distribution pin for partially closing the flow passage is inserted in the rectangular portion, and the flow passage opening degree of the pin is provided. The multilayer feedblock according to claim 15, wherein the flow rate of the resin is adjusted by. 17. The multi-layer feed block according to claim 15, wherein the multi-layer feed block is provided with means for providing a temperature distribution in order to gradually change the thickness of the thin film layer.