JP4620526B2 - Multilayer film manufacturing method and apparatus - Google Patents

Description

  The present invention relates to a method for producing a multilayer film formed by laminating a plurality of types of molten resins into a multilayer and a production apparatus therefor.

  For example, when a large number of layers having a high refractive index and a plurality of layers having a low refractive index are alternately laminated, the multilayer film becomes an optical interference film that selectively reflects or transmits light having a specific wavelength by optical interference between these layers. Such a laminated film can be used for, for example, a reflective polarizing plate, a coloring film, a film having a metallic luster, or a reflective mirror film by setting the wavelength region of light that is selectively reflected or transmitted to the visible light region. Is spreading. Moreover, it can be used as a film that selectively cuts ultraviolet rays by adjusting the number of layers and the interlayer thickness, and can also be used as an agricultural film for insect repellent. Furthermore, if the near infrared is selectively cut, it is useful as a film for window covering for solar radiation or a film for a video display panel such as a plasma display. It can be used as a film for preventing. Furthermore, in order to project an image on a show window, it is also promising as a hologram film using a film in which a multilayer film that selectively transmits each hue of RGB (red, green, blue) appropriately and appropriately is bonded.

  In view of this, various methods and apparatuses for manufacturing a multi-layered film that can be used for various applications have been proposed. For example, in Japanese Patent Application Laid-Open No. 4-278324 or Japanese Patent Application Laid-Open No. 2004-34299, two types of molten thermoplastic polymer polymers (hereinafter referred to as “polymers”) are formed into a predetermined number of layers using a multilayer feed block. A multilayer film manufacturing method and an apparatus therefor have been proposed, in which alternately stacked layered flows are formed, the layered flows are divided and then re-laminated to increase the number of layers.

However, in such a prior art, for example, as shown in FIG. 3A, when a poorly laminated portion is generated at the end 22 of the laminated flow having a rectangular cross section, this is shown in FIG. divided by C _{1 'surface} so as, when the re-stacked as shown in FIG. 3 (b), the thickness distribution is poor portion 22 each time repeating the lamination time division the thickness of the layer to the film center portion heterogeneous It appears as the part that became. Note that the reason why the layer flow is nonuniform in the cross section of the rectangular channel is because the stagnation part where the flow velocity becomes slow exists in the vicinity of the four corners of the cross section, and this causes the layer thickness to change. it is conceivable that. If it does so, the ratio of the defective part of the layer thickness contained in the multilayer film finally obtained by increasing the number of lamination | stacking will increase.

JP-A-4-278324 JP 2004-34299 A

  In view of the problems of the above-described conventional technology, the problem to be solved by the present invention is to manufacture a multilayer film in which the thickness of each layer is uniformly laminated, thereby producing a multilayer film excellent in optical characteristics and mechanical characteristics. A manufacturing method and an apparatus therefor are provided.

Here, as a method for producing a multilayer film for solving the above problems,
(1) At least two molten resins are alternately laminated in a multilayer feed block to form a laminated flow having a rectangular cross section, and the laminated flow is divided at a plurality of locations perpendicular to the laminated surface to have a rectangular cross section. A branched flow consisting of a plurality of divided laminated flows is formed, rearranged so that the laminated surfaces of the branched flows overlap and contact each other at the top and bottom, the dimensions of each branched flow are adjusted individually, and the adjusted branched flows are merged with each other And laminating and finally forming a multi-layered alternating laminate with an increased number of layers,
In this method, when the cross-sectional area of the laminated flow immediately before the division is defined as A and the cross-sectional areas before division of the divided laminated flows located at both ends of the laminated flow are defined as A ₁ and A ₂ , respectively, as a ₁ and _{a 2} satisfy the condition _{"5 <(a 1 + a 2} ) / a × 100 <30 ", Ri cut by dividing the both end portions of the laminated flow, and located at both ends before splitting producing how the multilayer film is provided the split multilayer flow portion characterized that you mixed statically.

Moreover, as a multilayer film manufacturing apparatus for solving the above problems,
( 2 ) A multi-layer feed block that forms a multi-layer laminar flow having a rectangular cross section by alternately laminating at least two molten resins, and the multi-layer flow laminated by the multi-layer feed is perpendicular to the laminating surface at a plurality of locations. Dividing and cutting means that divides and cuts both ends of the laminated flow; branching means that divides each divided laminated flow into independent branch flows; and each of the branched flows so that their laminated surfaces overlap each other vertically. And rearrangement means for adjusting the size of each branch flow, and the dimension-adjusted branch flows are joined to each other in multiple layers to form a multilayer alternating laminate flow, in the manufacturing apparatus of a multilayer film including a die for discharging a thin film, and a static mixer for mixing statically the divided cut split laminated flow from both ends of the rectangular cross section of the stacked flow I,
The divided cutting means sets the cross-sectional area A of the laminated flow before division from the multilayer feed block as A, and the cross-sectional area before division of each divided laminated flow divided at both ends of the laminated flow as A ₁ and A ₂ when defined, the a, production equipment of a multilayer film, characterized in that _{a 1} and _{a 2} are the means to cut and divided under the condition _{"5 <(a 1 + a 2} ) / a × 100 <30 " Is provided.

The multilayer film obtained by the present invention described above has a great effect that the problem of the conventional technique illustrated in FIG. 3 can be solved. That is, as described in FIG. 3, in order to increase the number of layers by dividing a polymer having a rectangular cross section by C ₁ ′, when restacking as shown in FIG. The portion 21 having a non-uniform layer thickness illustrated in FIG. 3B is stretched like the portion 22 illustrated in FIG. 3B, thereby preventing a phenomenon in which the portion having a good thickness is extremely small. For this reason, it is possible to satisfactorily produce a multilayer film having a very large number of layers in which the thickness of each layer is uniform. From this, the multilayer film manufactured by this invention is excellent in an optical characteristic and a mechanical characteristic.

  In particular, when the process consisting of the division and the re-stacking illustrated in FIG. 3 is not repeated once and repeated many times, in the related art, a portion having a good layer thickness is almost lost. On the other hand, in the present invention, since the “layer non-uniform portion 21” shown in FIG. 3A is cut out by a necessary minimum amount, only a laminar flow having an extremely good layer thickness is effective. It is possible to increase the number of layers by 2 to 3 times.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows a method and apparatus for forming a laminar flow P _{0 in} which at least two thermoplastic polymer polymers (polymers P _A , P _B ) are laminated in multiple layers using a multilayer feed block 1. FIG. 1 (a) is a plan view, FIG. 1 (b) is an enlarged plan view of an enlarged main part of FIG. 3 (a), and FIGS. 1 (c) and 1 (c). d) shows sectional views in the direction of arrows XX and YY in FIG. 3 (b), respectively.

1 (a), the at least two polymers (an example of FIG. 1, two polymers P _A and P _B) are supplied from the left side of the figure, these polymers P _A and P _B, After being introduced into the multi-layer feed block 1 from the inlets 6a and 6b and alternately laminated by the multi-layer feed block 1, they become the laminated flow P ₀ and exit from the outlet 8. The multilayer feed block 1 itself is known as disclosed in, for example, Japanese Patent Laid-Open No. 2003-112355, and such a known multilayer feed block 1 is preferably used in the present invention. Can do. For convenience of explaining the main features of the present invention, the multilayer feed block 1 illustrated in FIGS. 1 (a) to 1 (d) will be briefly described below.

  1A to 1D, the multilayer feed block 1 includes an upper restraining block 2a and a lower restraining block 2b, an upper branch block 3a and a lower branch block 3b, and a merge block 4. It is configured. At this time, as illustrated in FIG. 1 (b) in which the main part of FIG. 1 (a) is enlarged, the upper branch block 3a and the lower branch block 3b are provided in FIGS. 1 (c) and 1 (d). As illustrated in Fig. 1, polymer supply holes 7a and 7b having a rectangular cross section are alternately formed in the upper and lower sides.

Thus, the parallel flow paths 8a and 8b separating the flow of a large number of the partition plate 9 is provided in parallel at equal intervals of a polymer P _A flow and P _B to each other, and polymers P _A from the polymer feed holes 7a and 7b P _B can be supplied alternately. Next, the polymers P _A and P _B coming out of the parallel flow paths 8a and 8b are merged and bonded immediately after coming out of the parallel flow paths 8a and 8b, and as a result, alternately stacked rectangular shapes It becomes a laminated flow P ₀ having a cross section and flows out from the outlet 8 in the direction of the arrow indicated by the one-dot chain line.

As described above, the laminated flow P ₀ formed by the multilayer feed block 1 can be formed so that the number of laminations is 2 to 1000. However, if the number of laminations is too large, good lamination it is difficult to form a state more preferable number of stacked to form a multilayer stream P ₀ is 3-301 layers. Next, a method and apparatus for forming an extremely large number of layers while having a uniform layer thickness, which is one of the main features of the present invention, will be described in detail with reference to FIG.

In FIG. 2, FIG. 2 (a), after said laminating stream P ₀ is divided, an operation explanatory view showing the respective operations until the multi-layer film of being re-stacked are rearranged, FIG 2 (b) is a perspective view showing an example of an apparatus for embodying each operation. In addition, about the device element corresponding to each operation element in Fig.2 (a), in order to grasp | ascertain the relationship with FIG.2 (b), each reference code is attached | subjected and described.

Here, in the present invention, as described above, the multilayer feed block 1 has a rectangular cross section in which a plurality of polymers P _A and polymers P _B are alternately stacked (the cross-sectional area is “A”). A stream P ₀ is formed. Next, as illustrated in FIG. 2A, the laminated flow P ₀ thus formed is divided and cut, branched (if necessary, static mixing), rearranged, and The merging and bonding operations are performed in this order to form an unstretched multilayer sheet (laminate).

  At this time, as illustrated in FIG. 2B, the division cut operation is performed by the division cut unit 11, the previous branch operation is performed by the branch unit 12, and the previous rearrangement operation is performed by the rearrangement unit 13. The relocation operation is performed by the die 14. Note that the static mixing operation performed during the branching operation as necessary is omitted in FIG. 2B, but the branching channel 12a at both ends in the branching channels 12a, 12b, 12c, and 12d. And by installing a static mixer in 12d. Therefore, it goes without saying that the branch flow paths 12a and 12d at both ends may adopt a circular cross-section flow path instead of a rectangular cross-section flow path depending on the type of static mixer to be installed (for example, a Kenix type static mixer).

Hereinafter, the split cutting operation, the branching operation (including the static mixing operation as necessary), the rearrangement operation, and the merging and bonding operation will be described in detail.
First, in the dividing operation, the laminated flow P ₀ is divided at a plurality of locations (C ₁ , C ₂ , C _{3 in the} figure) perpendicular to the laminated surface, respectively, and divided laminated flows P ₁ , P ₂ , P ₃ and the operation of generating a _{P 4} is performed. At that time, in the present invention, the rectangular cross-sectional area before the division of the laminated flow P ₀ is A, and the sectional areas of the divided laminated flows P ₁ and P ₄ after the division originating from both ends of the laminated flow P ₀ are respectively represented. When defined as A ₁ and A ₂ , the divided laminated flows P ₁ and P ₄ are divided and cut so as to satisfy the condition defined by the following equation (1).
5 <(A ₁ + A ₂ ) / A × 100 <30 (1)
In this example, the laminated flow P ₀ is divided into four to be four divided laminated flows P ₁ , P ₂ , P ₃ and P ₄ , but can be divided into five or more, and a more preferable laminated flow P The division number of ₀ is 4 to 6 divisions.

When the division operation is completed as described above, a branch operation is performed in which the divided laminated flows P ₁ , P ₂ , P _3, and P ₄ are respectively made into independent branch flows. In this branching operation, the divided laminated flows P ₁ and P _{4 at} both ends are cut out so as to satisfy the condition defined by the above expression (1). In this case, “(A ₁ + A ₂ ) / A When “× 100” is defined as “R”, if this R is 5 (%) or less, a non-uniform portion of the layer cannot be sufficiently cut out, and a portion where the layer thickness at both ends is non-uniform is left. That is not preferable.

On the other hand, when 30% or more is cut off, the proportion of the defective portions at both ends becomes too large, and the meaning of correcting the defective portions at both ends is lost. In the case where R is 30% or higher, it means that there is a problem with the method of forming the laminated flow P ₀ of within the multilayer feed block 1, of possible to satisfactorily form a laminated flow P ₀ Is more important. Therefore, it is not necessary to cut out 30% or more under normal conditions. In addition, if both ends of the laminated flow P ₀ are cut off by 30% or more, the polymer flow rate in the portion corresponding to the branched flow P ₃ and the branched flow P ₄ forming a uniform alternating laminated flow is extremely reduced, which is inefficient. It becomes a manufacturing method of a multilayer film, and is not preferable.

At this time, as shown in the figure, the alternate laminated body formed of the polymer P _A and the polymer P _B is lost with respect to the divided laminated flows P ₁ and P ₄ at both ends of the laminated flow P _0. It is necessary to perform a static mixing operation. In addition, this static mixing operation uses various static mixing elements (for example, Kenix type static mixer, sulzer type static mixer, etc.) provided by Sulzer Ltd., Koch-Glitsch Inc., Chemineer Inc, etc. Can be done.

In this way, the mixing operation is performed on the divided laminated flow P ₁ and P ₄ at both ends, and loss of alternate lamination of the polymers P _A and polymer P _B, the polymer P _A and polymer P _B Are formed into a polymer stream P ₁ ′ and P ₄ ′ that are almost uniformly mixed. Incidentally, when such polymers P _A and polymer P _B and the polymer stream P ₁ were mixed to almost homogeneous _'and P _4' is formed, for example, nonuniform layer is accidentally reflected visible light iridescence It is possible to prevent the adverse effect of becoming a film of the present invention and the adverse effect of uneven thickness due to uneven stretching in the process of stretching the film.

As described above, each of the divided laminated flows P ₁ , P ₂ , P ₃ , P ₄ divided by the division operation is branched independently to form a branch flow, and / or both ends as necessary. When the operation of statically mixing the divided laminar flows P ₁ and P ₄ is completed, a rearrangement operation is then performed. This rearrangement operation means rearrangement so that the laminated surfaces of the branch flows P ₁ ′, P ₂ ′, P ₃ ′, and P ₄ ′ overlap each other in the upper and lower directions, and the widthwise dimension of each divided laminated flow Is an operation to adjust each.

According to this rearrangement operation, as illustrated in FIG. 2A, the branched flows P ₁ ′ and P ₄ ′ at both ends are narrow with a width of W before the rearrangement operation, and conversely with a large thickness. The strip shape (rectangular shape) is exhibited. In contrast, the polymer flows P ₁ ″ and P ₄ ″ after the rearrangement operation are greatly stretched in the width direction as shown in the figure, and the width is widened from W to W ′. On the other hand, the thickness is reduced and deformed so as to exhibit a horizontally long rectangular shape.

For this reason, if the amount of branch flows P ₁ ′ and P ₄ ′ cut off at both ends, that is, “R” defined by “(A ₁ + A ₂ ) / A × 100” is smaller than 30 (%), The thickness of the polymer streams P ₁ ″ and P ₄ ″ after the rearrangement operation can be reduced to reduce the degree to which P ₁ ″ and P ₄ ″ contribute to the overall multilayer film thickness. However, if “R” becomes smaller than 5 (%), it is not preferable because a defective portion with uneven thickness remains.

At that time, if the relocation operation shown in FIG. 2 (a) is briefly described, P ₁ ′ → P ₁ ″, P ₂ ′ → P ₂ ″, P ₃ ′ → P ₃ ″ and P ₄ ′ → "without relocation operation as that _{a, P 1 '→ P 3"} , P 2' P 4 → P 1 ", P 3 relocation operations such '→ _{P 2"} and _{P 4'} → _{P 4} ", or , P ₁ ′ → P ₄ ″, P ₂ ′ → P ₁ ″, P ₃ ′ → P ₂ ″ and P ₄ ′ → P ₃ ″ can be performed. And when such a rearrangement operation was performed, the portions alternately laminated to a uniform thickness were concentrated on the front surface of the multilayer film, and the non-uniformly alternately laminated portions were concentrated on the back surface which is the opposite surface. A multilayer film can be produced.

At this time, it goes without saying that the rearrangement operation can be realized by replacing the merging flow paths 13a, 13b, 13c, and 13d shown in FIG. For example, the rearrangement operations such as P ₁ ′ → P ₃ ″, P ₂ ′ → P ₁ ″, P ₃ ′ → P ₂ ″ and P ₄ ′ → P ₄ ″ are performed as shown in FIG. This can be realized by replacing the rearrangement order such as the paths 13a, 13b, 13c and 13d with the merging flow paths 13c, 13a, 13b and 13d.

When the rearrangement operation is completed in this way, the polymer flows P ₁ ′, P ₂ ′, P ₃ ′, and P ₄ ′ before the rearrangement operation all have the same width W ′ in the width direction. The polymer streams P ₁ ″, P ₂ ″, P ₃ ″, P ₄ ″ adjusted to Therefore, the polymer flows P ₁ ″, P ₂ ″, P ₃ ″, and P ₄ ″ all adjusted so as to have the same width W ′ are merged by the next merging / laminating operation and bonded. It can be done easily and satisfactorily.

As described above, when the preparation for performing the merging and bonding operation is completed, as illustrated in FIGS. 2A and 2B, for example, the polymer flow P ₁ ″, P at the inlet of the die 14 ₂ ″, P ₃ ″, P ₄ ″ are merged, and the polymer merged by the die 14 can be discharged from the die 14 as an unstretched multilayer sheet (laminate) S formed into a thin film polymer S.

  In addition, regarding the unstretched multilayer sheet S obtained in this way, those skilled in the art can form a multilayer film by using a conventionally known method and apparatus, and therefore detailed description thereof is omitted. Keep a simple explanation. That is, the unstretched multi-layer sheet is heated to a predetermined temperature and stretched in the longitudinal and / or transverse direction according to a conventional method, heat-treated at the predetermined temperature, and heat-relaxed if necessary, or necessary. Accordingly, the film can be formed into a multilayer film by re-longitudinal and / or re-lateral stretching and winding. At this time, a step of applying and drying a coating liquid for imparting some functionality to the film may be provided during or after the production process of the multilayer film.

A major feature of the multilayer film obtained by the present invention described above is that the problem of the prior art illustrated in FIG. 3 can be solved. That is, when the rectangular cross section 1 is divided by 21 and re-stacked in FIG. 3, the non-uniform portion 21 of the layer thickness shown in FIG. 3 (a) is stretched to the portion 22 shown in FIG. 3 (b). As a result, the portion with good thickness is extremely reduced. In particular, according to the example of FIG. 3, when divisional re-stacking is repeated many times, a portion having a good layer thickness is almost lost. Therefore, as illustrated in FIG. 2, if the branch flow P ₁ ′ and the branch flow P ₄ ′ at both ends where the layer thickness is not uniform are cut out by a necessary minimum amount, the layer thickness is extremely good. By effectively rearranging and stretching only the branch flow P ₂ ′ and the branch flow P ₃ ′, it becomes possible to increase the number of layers of a multilayer film having a uniform layer thickness by a factor of two or three.

  The preferred number of layers of the multilayer film obtained by the present invention described above is 5 to 4800, and such layers are produced by alternately laminating at least two kinds of polymers as already described in detail. Is done. In addition, the multilayer film obtained by the present invention is a film for the purpose of selectively transmitting and reflecting the incident light to the film by utilizing the difference in refractive index of each polymer, the purpose of increasing the strength of the film, or the gas barrier property. It is preferably used for the purpose of improving the functionality possessed by.

  In that case, the polymer which comprises a multilayer film in this invention can use the thermoplastic resin which has a drawable polymer as a main component, for example, polyethylene terephthalate, polyethylene-2,6-naphthalate, polybutylene terephthalate, etc. Aromatic polyester, Polyolefin such as polyethylene and polypropylene, Polyvinyl such as polystyrene, Polyamide such as nylon 6 (polycaprolactam), nylon 66 (poly (hexamethylenediamine-co-adipic acid)), and bisphenol A polycarbonate Examples thereof include homopolymers such as aromatic polycarbonate and polysulfone, and resins mainly composed of these copolymers. Examples of the copolymer component include isophthalic acid copolymerized polyethylene terephthalate and 2,6-naphthalenedicarboxylic acid copolymerized polyethylene terephthalate. Among the above thermoplastic resins, aromatic polyesters, polyolefins, and polyamides capable of molecular orientation by stretching are preferred, and polyethylene that exhibits excellent optical, mechanical, and thermal properties when the molecules are biaxially oriented. 2,6-naphthalate is also preferred. These resins may contain additives such as weathering agents, lubricants, antistatic agents, and pigments as necessary.

Hereinafter, the present invention will be further described by way of examples. In addition, each physical property in an example was measured with the following method.
(1) Color The color of the film sample and its intensity were visually observed under a fluorescent lamp.
(2) Maximum reflectance Using a spectrophotometer MPC-3100 manufactured by Shimadzu Corporation, the relative specular reflectance with an aluminum-deposited mirror at each wavelength is measured in a wavelength range of 350 to 2100 nm. The largest of the measured reflectances is the maximum reflectance. The measurement positions were 5 points (equal intervals) including both edges in the film width direction.

[Example 1]
First, it was prepared two polymers _{P A} and _{P B.} One of the polymers _{P A} is (a value measured in o-chlorophenol of 35 ° C.) intrinsic viscosity 0.62 dl / g a polyethylene-2,6-naphthalate (PEN) with spherical silica particles (average particle size of: 0.11 μm, 0.12 μm, ratio of major axis to minor axis: 1.02, average deviation of particle diameter: 0.1) was added. The other polymer P _B has an intrinsic viscosity (measured in 35 ° C. orthochlorophenol) of 0.63 dl / g of polyethylene terephthalate (PET) and an intrinsic viscosity (measured in 35 ° C. orthochlorophenol). Of 0.62 dl / g of polyethylene-2,6-naphthalate (PEN) blended at a weight percentage of 50:50 was prepared.

Next, the pelletized polymers P _A and P _B were dried at 160 ° C. for 5 hours, then fed to a separate extruder, melted, filtered through a polymer filter while metering with a gear pump, and the multilayer illustrated in FIG. Leaded to feed block 1. Then, the to form a laminated flow P ₀ having a rectangular cross-section are stacked in 101 layers alternately two molten polymer P _A and P _B in the multilayer feed block within 1, led to the illustrated apparatus 10 in FIG.

Then, the laminated flow P ₀ having the rectangular cross section is divided at three points perpendicular to the laminated surface, and a branched flow comprising _four divided laminated flows P ₁ , P ₂ , P ₃ and P ₄ having the rectangular cross section is obtained. Formed. At this time, the cross-sectional area of the laminated flow P ₀ immediately before the division is A, and the cross-sectional areas before division of the divided laminated flows P ₁ and P ₂ positioned at both ends of the laminated flow P ₀ are respectively A ₁ and A _2. Is divided by the dividing / cutting means 11 so that A ₁ = A ₂ , (A ₁ + A ₂ ) / A × 100 = 30 (%), and the branch flow P ₁ ′ and the branch flow P ₄ ′ are divided into nine elements. Were mixed with a Kenix type static mixer to adjust the total thickness to 55 μm. At this time, the divided laminated flow P ₂ and P ₃ were adjusted split position to be the same flow rate.

Next, the divided laminated flows P _{1 to} P ₄ divided in this way were led to the independent branch flow paths 12 a to 12 d to form the branch flows P ₁ ′ to P ₄ ′. Then, the rearrangement means 13 makes the width dimensions of the branch flows P ₁ ′ to P ₄ ′ have the same width so that the stacked surfaces of the branch flows P ₁ ′ to P ₄ ′ overlap and touch each other. A rearranged polymer stream P ₁ ″ to P ₄ ″ was formed. Next, the rearranged polymer streams P ₁ ″ to P ₄ ″ are guided to the die 14 which also serves as a merging and pasting means, joined together and re-laminated, and then the die 14 is maintained while maintaining the laminated state. was cast onto a casting drum, unstretched multilayer sheet (laminate) lamination number derived from split multilayer flow P ₂ and P ₃ are 202 layers was created S.

  This unstretched laminated sheet S is stretched 3.2 times in the longitudinal direction at a temperature of 150 ° C., and further stretched 3.5 times in the transverse direction at a stretching temperature of 155 ° C., and at 230 ° C. for 3 seconds. After heat setting and taking out from the tenter, both edges were trimmed by about 200 mm to obtain a multilayer film having a width of 1200 mm. The obtained multilayer film was a film that reflected light having a wavelength of about 550 nm out of visible light, and was a film that looked red visually. The measured values obtained at this time are shown in Table 1.

[Comparative Example 1]
A 202-layer multilayer film was sampled under the same conditions as in Example 1 except that the total thickness was adjusted to 25 μm using the two-division method shown in FIG. The collected multilayer film had a weak red color at the edges and a slight green color. The results obtained at this time are shown in Table 1.

  According to the production method of the present invention, a high-quality multilayer film having an extremely large number of layers in which the thickness of each layer is uniform can be produced satisfactorily. Moreover, the obtained multilayer film is excellent in optical characteristics and mechanical characteristics.

It is explanatory drawing for demonstrating the method and its apparatus for forming the lamination | stacking flow which laminated | stacked the at least 2 sort (s) of polymer in multiple layers using the multilayer feed block. It is explanatory drawing which illustrated typically one Embodiment concerning the method of this invention and its apparatus for performing the division | segmentation cutting, branching, rearrangement, and merge bonding of the laminated flow obtained by the multilayer feed block. It is explanatory drawing which illustrated the mode of operation of the division | segmentation restacking by a prior art.

Explanation of symbols

10: Apparatus for performing split cutting, branching, rearrangement, and merging and laminating of a laminated flow obtained by a multilayer feed block 11: Split cutting means 12: Branch means 12a, 12b, 12c, 12d: Each branch flow path 13 : Relocation means 13a, 13b, 13c, 13d: Each merging flow path 14: Die (merging and bonding means)
A: Cross-sectional area of the laminated flow immediately before the division A ₁ , A ₂ : Each divided laminated flow C _{1 to} C ₃ positioned at both ends immediately after the division: Each divided position P _{1 to} P ₄ : Each divided laminated flow P ₁ ′ ˜P ₄ ′: each branch flow P ₁ ″ to P ₄ ″: each branch flow rearranged and adjusted in size W: width of the branch flow before size adjustment W ′: width of the polymer flow after size adjustment

Claims (2)

At least two molten resins are alternately laminated in a multilayer feed block to form a laminated flow having a rectangular cross section, and the laminated flow is divided at a plurality of locations perpendicular to the lamination surface to obtain a plurality of divisions having a rectangular cross section. A branched flow consisting of a laminated flow is formed, rearranged so that the laminated surfaces of the branched flows overlap and touch each other, the dimensions of each branched flow are adjusted, and the sized adjusted branched flows are joined together and pasted A method of forming a multi-layered alternating laminate with a finally increased number of layers,
In this method, when the cross-sectional area of the laminated flow immediately before the division is defined as A and the cross-sectional areas before division of the divided laminated flows located at both ends of the laminated flow are defined as A ₁ and A ₂ , respectively, as a ₁ and _{a 2} satisfy the condition _{"5 <(a 1 + a 2} ) / a × 100 <30 ", Ri cut by dividing the both end portions of the laminated flow, and located at both ends before splitting method of manufacturing a multilayer film characterized that you mixed portion of the divided stack flow statically. A multilayer feed block that forms a multilayer laminar flow having a rectangular cross section by laminating at least two molten resins alternately, and the laminar flow laminated by the multilayer feed is divided at a plurality of locations perpendicular to the laminating surface. Divided cutting means for cutting off both ends of the laminated flow, branching means for branching each divided laminated flow into independent branch flows, and each of the branched flows are re-applied so that their laminated surfaces overlap each other vertically. A rearrangement means for arranging and adjusting the dimensions of each branch flow, and the branch flows adjusted in size are joined to each other in multiple layers to form a multilayer alternate laminate flow, thereby forming the multilayer alternate laminate flow into a thin film An apparatus for producing a multilayer film comprising: a die to be discharged; and a static mixer for statically mixing a divided laminated flow divided and cut from both ends of a rectangular cross section of the laminated flow,
  The divided cutting means sets the cross-sectional area A of the laminated flow before division from the multilayer feed block as A, and the sectional area before division of each divided laminated flow divided at both ends of the laminated flow as A ₁ And A ₂ A, A ₁ And A ₂ Is "5 <(A ₁ + A ₂ ) / A × 100 <30 ”means for dividing and cutting the multilayer film manufacturing apparatus.

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