JP2005349681A - Method and apparatus for producing sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a sheet which can reduce the dispersion of lamination thickness without enlarging a lamination device and an apparatus producing a sheet. <P>SOLUTION: In a method for producing a multi-layer laminated film, in order to reduce the thickness dispersion of the laminated film in which at least two kinds of thermoplastic resin layers are laminated, the lamination device in which the size of each part of a channel satisfies a prescribed relationship is used. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

The present invention relates to a sheet manufacturing method and a manufacturing apparatus.

In general, the film production process involves melting a resin with an extruder, extruding the molten resin into a sheet form from a die, and cooling and solidifying it with a casting drum to form an unstretched film. It has the process of extending | stretching at least to one direction and winding up in roll shape. In this film manufacturing process, there is a proposal for forming a multilayer laminated film in-line by providing a multilayer laminating apparatus on the upper part of the die. As the method, there can be mentioned three types: a multi-layer method using a multi-layer feed block, a multi-layer method using one or more laminating apparatuses, and a method using a combination of a feed block and a laminating apparatus.

  A multilayer laminated film is obtained using such a multilayer feed block or a laminating apparatus, for example, using a film forming apparatus shown in FIG. FIG. 4 is a schematic view showing an example of a film forming apparatus for use in a film manufacturing process. This apparatus is an example of a biaxial stretching apparatus that forms a resin sheet. A resin X chip is put into the extruder 1 to make a molten resin (molten material), and then the molten resin is made to flow constant per unit time by the gear pump 2, and foreign matters are removed by the filter 3. Also, a resin Y chip is put into the extruder 4 to make a molten resin (molten material), then the molten resin is made to flow at a constant rate per unit time by the gear pump 5, foreign matters are removed by the filter 6, and then the molten resin X And Y are introduced into the feed block 7 or the laminating apparatus 7 and laminated, and the molten base is widened and discharged in the width direction by the heated base 8, cast by the cooling roll 9, and then run by the longitudinal stretching machine 10. The resin is stretched in the direction and stretched in the width direction by the transverse stretching machine tenter 11, and then wound around the winding roll 12.

As a means for laminating a multilayer laminated film using a multilayer feed block, proposals have conventionally been made to form a multilayer film by using a co-extrusion feed block. ,
This is disclosed in, for example, Patent Document 1 and Patent Document 2. In the case of such a device, if the number of layers to be stacked is small, the device is small and the manufacturing of the device can be reduced. However, as the number of stacks increases, the feed block device itself becomes large and the manufacturing cost of the device increases. There was a problem of becoming higher.

  Moreover, what was disclosed by patent document 3 is known about the lamination | stacking means of the multilayer laminated film using a lamination apparatus. This is to form or form a multilayer laminated film by a series of operations of repeatedly dividing and recombining the layers as the resin passes through the laminating apparatus. When the laminating apparatus is used, the multi-layer laminating apparatus is small and can easily produce a multilayer laminated film. However, the laminating apparatus has a flow path structure that repeats the division and recombination of the layers. Depending on the flow path structure of the resin, flow velocity distribution unevenness occurs in the film width direction and the film thickness direction. The desired characteristics and shape of the laminated film may not be obtained.

  A method of forming a multilayer laminated film by combining a feed block and a laminating apparatus has also been proposed. This includes a feed block method and a multiplier method, both of which are disclosed in Patent Document 4. In the multilayer laminated film formed by these methods, since the X layer made of resin X and the Y layer made of resin Y are laminated, resin X and resin Y are melted separately in an extruder, and each resin is laminated in multiple layers. After branching in the feed block, the branched layers are stacked, guided to a flow path partitioned by parallel plates, and then passed through one or more stacking devices to further add resin X and resin Y in the thickness direction. It is multi-layered, extruded into a sheet form from the die, cooled and solidified with a casting drum to form an unstretched film, and this unstretched film is stretched in at least one direction of the running direction and the width direction and wound into a roll. . In this multi-layer laminating apparatus, problems that occur when the above-described feed block and laminating apparatus are used in the middle size occur at the same time. However, uneven thickness of the laminating apparatus mainly becomes a problem.

The film manufactured as described above also needs to reduce the overall thickness unevenness (lamination thickness unevenness) in the same manner as a single-layer normal film. In particular, in the case of an optical film used for a window pasting film having excellent tear resistance, a polarizing reflection film provided with a multilayered optical interference effect as a function, etc., it is required to make the thickness unevenness precise.
US Pat. No. 3,773,882 US Pat. No. 3,884,606 JP-A-55-145522 US Pat. No. 3,565,985

In the above method, particularly when a small facility is used, the thickness of one layer in the laminated film is deteriorated in the thickness unevenness in the thickness direction and the width direction of the entire film, and a multilayer laminated film having a uniform laminated thickness is obtained. It was difficult to manufacture. As a cause thereof, there has been a problem that partial flow velocity unevenness occurs in the flow of the resin flowing through the flow path in the laminating apparatus, and the laminated cross section is likely to be disturbed. An object of the present invention is to solve such a problem and to provide a method and an apparatus for producing a multilayer laminated film with less unevenness in the laminated thickness in the thickness direction and the width direction of the entire film even when relatively small equipment is used. To do.

The present invention has reached the following present invention as a result of intensive studies to solve the above problems. The multi-layer laminated film laminating apparatus of the present invention has the following configuration in an example process in order to solve the above object. That is,
(1) A first flow having a rectangular cross section in which the length of a short side in a plane orthogonal to the traveling direction is H, and the length of the long side is a length obtained by multiplying the ratio p by the length H of the short side. A resin flow is caused to flow into the path, and the resin flow is divided into two in the long side direction at a half point A to form the first and second resin flows, and the formed first and second resin flows are In the short side direction, guide to the opposite direction to each other and move to the relay point B, to guide the first and second resin flows in the opposite direction in the long side direction, and to stack in the short side direction at the stacking point C The cross-sectional shapes in the plane including the short side direction and the long side direction of the laminated first and second resin flows are compressed by a ratio r times in the short side direction, respectively, and the compressed first and second The two resin streams are merged at a merge point D to form a first merged resin stream, and the formed first merged resin stream is pushed out of the base to form a sheet. The positional relationship among the ratio p, the ratio r, and the bisection point A, the relay point B, the stacking point C, and the junction point D is the following relationship: A sheet manufacturing method characterized by satisfying the formula. 1.8 ≦ p ≦ 2.2 and 0.4 ≦ r ≦ 0.6 and 0.9 ≦ L ₃ /H≦4.0 and 0.8 ≦ L ₁ / L ₃ ≦ 1.2 and 0.8 ≦ L ₂ / L ₃ ≦ 1.2
Where L ₁ is the length in the direction of travel from the bisection point A to the relay point B, L ₂ is the length in the direction of travel from the relay point B to the stacking point C, and L _{3 is the} stacking point. It is the length in the direction of travel from C to the junction D.
In addition, the thickness unevenness measurement method uses a transmission electron microscope, takes a cross-sectional photograph of a multilayer laminated film, measures the layer configuration and each layer thickness, and regards the calculated value of the variation between the laminations as the thickness unevenness.
(2) Further, as a preferred embodiment of the present invention, the positional relationship between the stacking point C and the merging point D satisfies the following relational expression, and the method for producing a sheet according to (1).
1.8 ≦ L ₃ /H≦3.0
(3) A first flow having a rectangular cross section in which the length of the short side in the plane orthogonal to the traveling direction is H, and the length of the long side is a length obtained by multiplying the ratio p by the length H of the short side. A resin flow is caused to flow into the path, and the resin flow is divided into two in the long side direction at a half point A to form the first and second resin flows, and the formed first and second resin flows are In the short side direction, guide to the opposite direction to each other and move to the relay point B, to guide the first and second resin flows in the opposite direction in the long side direction, and to stack in the short side direction at the stacking point C The cross-sectional shapes in the plane including the short side direction and the long side direction of the first and second resin flows arranged side by side are respectively compressed to a ratio r times in the short side direction, and the compressed first and second The two resin streams are merged at a merge point D to form a first merged resin stream, and the formed first merged resin stream is supplied to the die, from the die A sheet manufacturing method for forming a sheet by extruding, wherein the ratio p, the ratio r, and the positional relationship between the bisection point A, the relay point B, the stacking point C, and the junction point D are as follows: A sheet manufacturing method satisfying the following relational expression:
1.8 ≦ p ≦ 2.2 and 0.4 ≦ r ≦ 0.6 and
0.9 ≦ L ₃ /H≦4.0 and 1.6 ≦ L ₁ / L ₃ and 1.3 ≦ L ₂ / L ₃
Where L ₁ is the length in the direction of travel from the bisection point A to the relay point B, L ₂ is the length in the direction of travel from the relay point B to the stacking point C, and L _{3 is the} stacking point. It is the length in the direction of travel from C to the junction D.
(4) The sheet manufacturing method according to (3), wherein a positional relationship among the bisector A, the relay point B, the stacking point C, and the joining point D satisfies the following relational expression: .
2.26 ≦ L ₃ /H≦3.0 and 2.5 ≦ L ₁ / L ₃ and 2.0 ≦ L ₂ / L ₃
(5) A rectangular section having a length of a short side H ′ in a plane orthogonal to the traveling direction and a length of the long side multiplied by a ratio p ′ to the length H ′ of the short side. The first combined resin flow is caused to flow into the two flow paths, and the resin flow is divided into two in the long side direction at a half point A ′ to form third and fourth resin flows. The third and fourth resin flows are guided in opposite directions in the short side direction and moved to the relay point B ′, and the third and fourth resin flows are guided in opposite directions in the long side direction, and the stacking point C ′ is moved so as to be laminated in the short-side direction, and the cross-sectional shapes in the plane including the short-side direction and the long-side direction of the laminated first and second resin flows are ratios r ′ in the short-side direction, respectively. A second merged resin stream formed by merging the compressed third and fourth resin streams at merging point D ′ to form a second merged resin stream (1) to (4), wherein the ratio p ′, the ratio r ′, and the bisector A ′, A positional relationship among the relay point B ′, the stacking point C ′, and the junction point D ′ satisfies the following relational expression.
1.8 ≦ p ′ ≦ 2.2 and 0.4 ≦ r ′ ≦ 0.6 and 0.9 ≦ L ′ ₃ /H′≦4.0 and 0.8 ≦ L ′ ₁ / L ′ ₃ ≦ 1 .2 and 0.8 ≦ L ′ ₂ / L ′ ₃ ≦ 1.2
Here, L ′ ₁ : Length in the traveling direction from the bisector A ′ to the relay point B ′, L ′ ₂ : Length in the traveling direction from the relay point B ′ to the stacking point C ′, L ′ ₃ : Length in the traveling direction from the stacking point C ′ to the confluence point D ′.
(6) Two or more different resin flows are laminated in the short side direction by a feed block to form a resin flow having a layer structure of two or more layers, and the resin flow is caused to flow into the first flow path. The method for producing a sheet according to any one of (1) to (5), which is characterized.
(7) The sheet production according to any one of (1) to (5), wherein two kinds of different resins are caused to flow into each of the partial flow paths obtained by dividing the first flow path in the long side direction. Method.
(8) At the bisector A, the length of the short side in the plane orthogonal to the resin traveling direction is H, and the length of the long side is a length obtained by multiplying the length H of the short side by the ratio p. A first flow path having a rectangular cross section, connected to the first flow path at the bisecting point A, formed to divide the first flow path into two in the long side direction, and the resin In the short side direction, they are led in the opposite directions in the short side direction to the relay point B, then in the long side direction, led in the opposite direction to each other to reach the stacking point C, and then in the short side direction. Is a resin laminating apparatus comprising first and second intermediate flow paths that merge at a confluence point D, the ratio of which is gradually compressed, the ratio r times, wherein the ratio p, the ratio r, In addition, the positional relationship among the bisection point A, the relay point B, the stacking point C, and the junction point D satisfies the following relational expression. Sheet manufacturing apparatus according to claim Succoth.
1.8 ≦ p ≦ 2.2 and 0.4 ≦ r ≦ 0.6 and 0.9 ≦ L ₃ /H≦4.0 and 0.8 ≦ L ₁ / L ₃ ≦ 1.2 and 0.8 ≦ L ₂ / L ₃ ≦ 1.2
Where L ₁ is the length in the direction of travel from the bisection point A to the relay point B, L ₂ is the length in the direction of travel from the relay point B to the stacking point C, and L _{3 is the} stacking point. It is the length in the direction of travel from C to the junction D.
(9) The sheet manufacturing apparatus according to (8), wherein the following relational expression is satisfied.
1.8 ≦ L ₃ /H≦3.0
(10) At bisector A, the length of the short side in the plane orthogonal to the resin traveling direction is H, and the length of the long side is a length obtained by multiplying the length H of the short side by the ratio p. A first flow path having a rectangular cross-section, and connected to the first flow path at a bisecting point A, formed so as to divide the first flow path into two in the long side direction, and the resin In the short side direction, they are led in the opposite directions in the short side direction to the relay point B, then in the long side direction, led in the opposite direction to each other to reach the stacking point C, and then in the short side direction. Is a resin laminating apparatus comprising first and second intermediate flow paths that merge at a confluence point D, the ratio of which is gradually compressed, the ratio r times, wherein the ratio p, the ratio r, In addition, the positional relationship between the bisection point A, the relay point B, the stacking point C, and the junction point D is expressed by the following relational expression: Sheet manufacturing apparatus characterized by plus.
1.8 ≦ p ≦ 2.2 and 0.4 ≦ r ≦ 0.6 and
0.9 ≦ L ₃ /H≦4.0 and 1.6 ≦ L ₁ / L ₃ and 1.3 ≦ L ₂ / L ₃
Where L ₁ is the length in the direction of travel from the bisection point A to the relay point B, L ₂ is the length in the direction of travel from the relay point B to the stacking point C, and L _{3 is the} stacking point. It is the length in the direction of travel from C to the junction D.
(11) The sheet manufacturing apparatus according to (10), wherein the following relational expression is satisfied.
2.26 ≦ L ₃ /H≦3.0 and 2.5 ≦ L ₁ / L ₃ and 2.0 ≦ L ₂ / L ₃

According to the present invention described above, the laminating apparatus having the above-mentioned flow path shape is small, but the overall or partial flow velocity unevenness that occurs in the flow of the resin is reduced, and the thickness of the entire film is less likely to be disturbed. An excellent multilayer laminated film with little unevenness in the laminated thickness in the direction and the width direction can be obtained.

  In the present invention, a thermoplastic resin is preferably used in the present invention, but is not particularly limited. For example, polyolefin resins such as polyethylene, polypropylene, and polymethylpentene, polyamide resins such as nylon 6 and nylon 66, polyethylene terephthalate, and polybutylene. Polyester resins such as terephthalate, polyethylene-2, 6-naphthalate, polycarbonate resins, polyarylate resins, polyacetal resins, polyphenylene sulfide resins, acrylic resins, and the like can be used.

  These resins may be homo-resins, copolymerized or blended. Among these resins, various additives such as antioxidants, antistatic agents, crystal nucleating agents, inorganic particles, organic particles, viscosity reducers, thermal stabilizers, lubricants, infrared absorbers, ultraviolet absorbers. Etc. may be added.

  When a thermoplastic resin is used as the resin used in the present invention, at least one kind is preferably a polyester resin, among which polyethylene-2, 6-naphthalate and polyethylene terephthalate are preferable, and polyethylene terephthalate is particularly preferable.

  In the case where a thermoplastic resin is used as the resin used in the present invention, at least one kind is 2,2-bis (4′-β-hydroxyalkoxyphenyl) propane group and / or from the viewpoint of heat resistance of the thermoplastic resin. Or it is preferable that it is a thermoplastic resin which has a cyclohexane group. Examples of the resin include copolymerized polyester, polycarbonate resin, modified polycarbonate resin, polyarylate resin, and modified polyarylate resin.

  In the case where a thermoplastic resin is used as the resin used in the present invention, at least one kind is 2,2-bis (4′-β-hydroxyalkoxyphenyl) propane and / or from the viewpoint of heat resistance and transparency. Polyester obtained by copolymerizing cyclohexanedimethanol is preferred. As the compound having a 2,2-bis (4′-β-hydroxyalkoxyphenyl) propane structure, for example, a polyester obtained by polycondensation of a bisphenol A ethylene oxide adduct as a jetylene glycol component is preferably used. As such a polyester, at least bisphenol A ethylene oxide adduct as a diol component and / or cyclohexanedimethanol, and other diols such as ethylene glycol, trimethylene glycol, tetramethylene glycol, cyclohexanedimethanol, neopentyl glycol Obtained by polycondensation with any combination of a diol component selected from polyalkylene glycol and the like and a dicarboxylic acid component selected from, for example, terephthalic acid, isophthalic acid, phthalic acid, naphthalene dicarboxylic acid, adipic acid, sebacic acid and the like Examples thereof include copolymer polyesters.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. FIG. 1 schematically shows a cross-sectional shape and a positional relationship of each part of each flow path of a sheet manufacturing method and a laminating apparatus of the present invention. Here, it is assumed that a resin flow in which two types of resins, resin X and resin Y, are juxtaposed, is passed through the laminating apparatus. In the hatched portion depicted in this figure, the bisection point A, the relay point B, the stacking point C, and the junction point D represent a cross section perpendicular to the traveling direction of the flow path at each position. The channel itself is not shown directly.

  In FIG. 1, a first channel having a rectangular cross section at a bisector A having a short side length H and a long side length multiplied by the ratio p to the short side length H is shown in FIG. The resin flow in which the resin X and Y are juxtaposed at the position of the partial cross section X and Y at the bisector A of each partial flow path in each partial flow path divided into two in the side direction is the direction of arrow A (traveling direction A ). Phase I is the point until bisector A. At the half point, this resin flow is divided into two in the long side direction, and the first and second resin flows are formed. Then, along the traveling direction, the first and second resin flows are guided in directions opposite to each other in the short side direction and reach the relay point B. This is Phase II. From here, the first and second resin flows are guided in directions opposite to each other in the long side direction (directions approaching each other), and are arranged in the short side direction at the stacking point C. At this point, the two resin streams are still placed in a stacked positional relationship and do not contact each other. This is Phase III. Then, the cross-sectional shapes in the plane including the short side direction and the long side direction of the laminated first and second resin flows are respectively compressed by a ratio r times in the short side direction, and the compressed first and second types are compressed. These resin flows are merged at a merge point D to form a merged resin flow. Usually, the ratio r is 0.4 to 0.6 times. This is called Face IV. In the steady state, when there is no compression of the volume of the resin flowing through Phase IV and there is no change in the flow velocity, the dimension in the long side direction of the resin flow is expanded to 1 / r times corresponding to the compression. The Actually, depending on conditions such as the type of resin, volume compression may occur, and strictly speaking, it may not be 1 / r times. Such a situation is said to be substantially 1 / r times.

And the length of the traveling direction of the part in the phase II situation (from the bisecting point A to the relay point B) is L ₁ , the traveling direction of the part in the phase III situation (from the relay point B to the stacking point C) Is the length L ₂ , and the length in the traveling direction of the portion in the phase IV state (from the stacking point C to the confluence point D) is L ₃ .

The above is the stacking operation performed by one stacking apparatus. When such a laminating apparatus is combined in multiple stages in series, the combined resin flow that has reached the state of phase IV described above is guided to the inlet of a laminating apparatus having another similar structure, and the same phases I to IV are repeated. As a result, the number of stacked layers can be gradually increased. Note that it is not necessary for all the stacking devices in each stage to have the same shape. For example, H ′, L ′ ₁ , L ′ ₂ , L ′ ₃ , or the dimensions and ratios corresponding to H, L ₁ , L ₂ , L ₃ , p and r, which are the dimensions and ratios of the respective parts, match or are different from these. , P ′ and r ′. In general, the positional relationship between the intermediate flow paths at the relay point B is preferably as close as possible as shown in FIG. That is, the shortest distance of the cross section of each intermediate flow path at the relay point B (the distance between the vertices closest to the other intermediate flow path) is 0.26 times or less of H.

  In addition, the discharge amount is adjusted so that the lamination thickness ratio of the two types of thermoplastic resins X and Y is approximately X / Y = 1 in the laminating apparatus, and, for example, the resin X is 5 layers and the resin Y is in the feed block. For example, the layers were alternately stacked in the thickness direction consisting of four layers. For example, the resin flow merged as a nine-layer structure may be flowed into the laminating apparatus to be multilayered.

  Table 1 shows two types of thermoplastic resins X and Y, the discharge rate is adjusted so that the lamination thickness ratio is approximately X / Y = 1, and two types of resin X are used in the feed block, and five layers of resin Y Are laminated in a 9-layer structure alternately in the thickness direction consisting of 4 layers, and after flowing into the laminating apparatus and laminating, they are extruded into a sheet form from the die, cooled and solidified with a casting drum to form an unstretched film, and this unstretched film For stretched films obtained by stretching the film in at least one of the running direction and the width direction, the number and structure dimensions of each laminating device used, the thickness of the stretched multilayer laminated film, the maximum layer thickness, the minimum layer thickness, the average thickness, the book Table 1 shows the inter-layer variations measured using the evaluation method, and the inter-layer variations and device size evaluated comprehensively.

  Next, the state of thickness unevenness in each layer will be described. FIG. 2 is an image diagram showing flow velocity contour lines of the resin flow in each phase, and FIG. 3 schematically shows a cross-sectional state of the laminated film laminated as described above.

  When the molten resin A flows from the phase I to the phase II where the resin A is introduced into the cross section Y and the resin B is introduced into the cross section Z, the resin X flows upward and the resin Y flows downward as shown in FIG. Become. The maximum flow velocity of the resin flow is at the center of the cross section until each resin moves in the flow direction from Phase I. However, in Phase II, the position of the maximum flow velocity is shifted from the center of the cross section. The resin Y shifts to the upper side of the cross section y below the center. This is due to the effect of the viscosity and inertia of the resin. When moving from Phase I to Phase II, the resistance of the wall surface is small, and the resin itself will continue to move in the same direction at the same speed and physical properties. This is because the viscosity of the resin, which tries to flow together as much as possible with the adjacent resin part, is affected.

  In addition, the resin flow downstream of Phase II, that is, until the layers are stacked in the film thickness direction from Phase II to Phase III, affects the resin flow of Phase II, and the position of the maximum flow velocity of Phase II is located inside the laminator. Will be biased. When the above flow phenomena are combined, the resin flow center in Phase II is biased as II in FIG. The small circle part in the center of the circle becomes the maximum flow velocity part, and the flow velocity becomes faster and the flow velocity becomes slower as it goes outward.

  From Phase III to Phase IV, it becomes a shape that compresses in the thickness direction while expanding in the width direction, so the resin flow tends to be disturbed, especially when the stacking device is multistage, such disturbance in the first-stage stacking device The merged resin flow with the flow into the first flow path of the second-stage laminating apparatus is affected by the flow flowing in the vertical direction between Phase I and Phase II by repeating Phases I to IV, As shown by IV in FIG. 2, flow velocity unevenness occurs on the left and right sides of the cross section, and a phenomenon occurs in which the variation in lamination between the multilayer laminated films is deteriorated.

  Also, due to this phenomenon, in the laminated film made of two types of resins X and Y, a difference in thickness between the left and right laminated layers laminated on the layer V made of the resin X and the layer W made of the resin Y is generated. The state of lamination in the cross section is shown in FIG.

The evaluation method will be described. For example, when the thicknesses of the layers made of each resin X and the thicknesses of the layers made of the resin Y are the same as the design values, the interlayer variation is caused by the resin X and Y in the multilayer laminated film. Among these, the thickness of each layer made of the same resin is measured, and the variation in thickness in all the layers is expressed as a percentage. It can also be stopped by the following formula.
Interlayer variation = ((maximum layer thickness) − (minimum layer thickness)) / (average layer thickness)
Here, the thickness of the thickest layer of each layer is the maximum layer thickness, and the thickness of the thinnest layer is the minimum layer thickness. The average thickness is an average value of the thicknesses of the respective layers made of the same resin measured in at least three places in the width direction of the film. Average thickness = 1 / N × (d ₁ + d ₂ +... + D _N-1 + d _N ) (where N is an integer of 3 or more, and d _N is the surface of the Nth layer) The average thickness in the inward direction is shown.) The maximum layer thickness and the minimum layer thickness are defined for each part in the in-plane direction of the film. Accordingly, interlayer variations can also be defined for each part in the in-plane direction of the film. However unless otherwise specified, the maximum layer also minimum layer thickness thickness also, the average value of one single layer on the side without the direction of the thickness d _1, d _2, defined ····· d _N-1, d _N To do.

For example, the ratio p is 2, the ratio r is 0.5, L3 / H is _0.91, L 1 / _{L 3} is _0.8, L 2 / _{L 3} by using the one lamination apparatus of 0.8 Film A 129 layer unstretched film with a thickness of 96 μm was prepared, and the film width was divided into 6 equal parts, and the inter-laminar variation was measured in the five film thickness directions that are the boundary line. The average interlayer variation was 85%, and the average layer variation of the resin Y layer (Y layer) was 88%. In addition, it is possible to produce a multilayer laminated film in which an unstretched film is stretched at a stretch ratio of 3 times or more in at least one direction of the running direction and the width direction. As a result of measuring the interlayer variation of the stretched film in the same manner as the unstretched film, the interlayer variation of the A layer was 94% on average and the variation between the laminations of the B layer was 100% on average. There was a tendency to get worse. This is because the thickness of each layer is not uniformly stretched in the width direction of the film when stretched in at least one direction of the running direction and the width direction.

FIG. 5 is a graph showing changes in interlayer variations depending on the shape conditions of the laminating apparatus shown in Table 1. 5A shows a case where the lengths of L ₁ and L ₂ of the laminating apparatuses in No. 1 to No. 6 in Table 1 are substantially the same, and FIG. 5B shows the lamination in No. 8 to 12 in Table 1. The case where the lengths of L ₁ and L ₂ of the apparatus are different is shown. For the evaluation items in Table 1, the inter-layer variations and the size of the apparatus were comprehensively evaluated and represented by ○ and ×. The horizontal axis of (a) and (b) represents L ₃ / H, the vertical axis represents the inter-layer variation (%), and the inter-layer variation is within 30% between the two dotted lines in each figure. Between, the variation between layers is less than 100%. It can be seen that the interlayer variation tends to change as shown in FIG. 5 depending on L ₃ / H. In the case of No. 7 and No. 13 in Table 1, although the interlayer variation is good, L ₃ / H is as large as 5.00 or 6.00 and the laminating apparatus itself becomes large, so the object of the present invention is Cannot be achieved.

Considering the relationship between the laminating apparatus of each type in Table 1 and the variation between the laminations of the multilayer laminated film, the result is the relationship between the lengths of L ₁ , L ₂ , and L ₃ with respect to H as shown in FIG. It can be seen that if predetermined conditions described later are satisfied, interlayer variations are improved, and if not satisfied, interlayer variations tend to deteriorate, or interlayer variations are improved, but the stacking apparatus becomes large. No. in Table 1 No. ₁ when L ₁ and L ₂ are short with respect to H. Interlayer variation occurs turbulence in the resin flow in the stacking device when the length of L ₃ relative to H is short as 8 has deteriorated. In Table 1, No. 7 and No. No. 13 can obtain good inter-lamination variations of 20% and 29%. However, as described above, there is a problem that the laminating apparatus becomes large, and the evaluation is x.

  No. 2, No. 6, No. 9 and No. As a result of measuring the above-mentioned interlayer variation when using the 12 laminating apparatus, it was within 100%. 3-5, No. When the laminating apparatus of 10 to 11 was used, the interlayer variation of the multilayer laminated film was improved and was within 30%. From these results, it has been found that when the following conditions are satisfied, it is relatively small and good stacking accuracy can be obtained.

  A multilayer laminated film was produced under conditions within and outside the shape range of the laminating apparatus of the present invention, the interlayer variation was evaluated, and the effectiveness of the present invention was confirmed.

Hereinafter, the present invention will be further described by way of examples. The physical properties in the examples were measured by the following methods.
(1) Lamination Thickness, Number of Laminations The layer configuration of the film was determined by observation with an electron microscope for a sample cut out of a cross section using a microtome. That is, using a transmission electron microscope HU-12 type (manufactured by Hitachi, Ltd.), the cross section of the film was magnified and observed at 10000 and 100000 times, a cross-sectional photograph was taken, and the layer structure and each layer thickness were measured. Incidentally, it was stained with RuO ₄ staining in order to clarify the layer structure.
(2) Intrinsic Viscosity Polyester is dissolved in o-chlorophenol, and a value calculated from the following equation from the solution viscosity measured at 25 ° C. is used. That is, ηsp / C = [η] + K [η] 2 · C
Here, ηsp = (solution viscosity / solvent viscosity) −1, C is the dissolved resin weight per 100 ml of solvent (g / 100 ml, usually 1.2), and K is the Huggins constant (assuming 0.343). The solution viscosity and solvent viscosity were measured using an Ostwald viscometer.
[Example 1] As the resin X, polyethylene terephthalate having an intrinsic viscosity of 0.65 (glass transition temperature of 76 ° C) added with 1 wt% of an infrared absorber and 1 wt% of colloidal silica was used. As resin Y, bisphenol A ethylene oxide adduct 30 mol% copolymerized polyethylene terephthalate (glass transition temperature 74 ° C.) having an intrinsic viscosity of 0.65 was used. These resins X and Y were each dried and then supplied to an extruder. Resins X and Y were respectively melted at 280 ° C. with an extruder, and after passing through a gear pump and a filter, the thermoplastic resins X and Y merged with a feed block were divided into five layers of resin X and resin Y of A nine-layer structure in which four layers are alternately stacked in the thickness direction, and both surface layer portions are made of the thermoplastic resin X. Here, the discharge amount was adjusted so that the lamination ratio, which is the ratio of the thicknesses of the layers made of the resins X and Y, was approximately X / Y = 6. In the process of repeating splitting and recombination of the layers using two stacking devices with a ratio p of 2, H of 11 mm, L ₁ of 40 mm, L ₂ of 40 mm, L ₃ of 40 mm, and a ratio r of 0.5. By superimposing both surface layers made of resin X, two layers of resin X become one layer. The thus obtained laminate consisting of a total of 33 layers was supplied to a T-die and formed into a sheet shape, and then rapidly cooled and solidified on a casting drum maintained at a surface temperature of 25 ° C. while applying electrostatic force from a wire. Then, it was heated with a roll group set at 80 ° C., stretched 2.8 times in the running direction, led to a tenter, preheated with hot air at 100 ° C., and stretched 3.2 times in the width direction. The stretched film was heat-treated with hot air at 150 ° C. in a tenter as it was, cooled to room temperature, and wound up. The thickness of the obtained film was 100 μm. As shown in Table 2 in the width direction of the stretched film, the interlaminar variation of the resin A at the center of the film was measured as a result of measuring the interlaminar variation of the two fulcrum points and the center at a distance of 300 mm from both edges. 33% and Resin B were 73%, and the left side of the film traveling direction was 52% of resin A interlayer variation, Resin B was 79%, the right side was Resin A 41%, and Resin B was 75%. It was.

[Example 2] A film having a thickness of 101 µm was obtained under the same apparatus and conditions as in Example 1. However, the ratio p is 2, H is 11 mm, L ₁ is 70 mm, L ₂ is 52 mm, L ₃ is 40 mm, and the ratio r is 0.5. Nine layers laminated in the thickness direction, consisting of 5 layers of X and 4 layers of resin Y, passed through two main laminating devices to form a structure of 33 layers, and the results obtained are shown in Table 3. Show.

The present invention can be applied to the production of multilayer laminated films having high interlayer variations, but the application range is not limited thereto.

Schematic showing the change of resin given by the laminating equipment Flow velocity contour map of resin flow in each phase Cross-sectional view of a multilayer laminated film formed using a conventional lamination device Process for forming multilayer laminated film Graph showing changes in stacked between the variation due to the shape condition of the stacked device (L 3 _{/ H)} Graph showing changes in stacked between the variation due to the shape condition of the stacked device (L 3 _{/ H)}

Explanation of symbols

1: Extruder 2: Gear pump 3: Filter 4: Extruder 5: Gear pump 6: Filter 7: Feed block or laminating device 8: Base 9: Cooling roll 10: Longitudinal stretcher 11: Transverse stretcher tenter 12: Winding roll
V: layer
W: layer

Claims (11)

Resin the first flow path having a rectangular cross section in which the length of the short side in the plane orthogonal to the traveling direction is H, and the length of the long side is the length p multiplied by the length H of the short side. A first flow and a second flow in the long side direction at a half point A to form first and second resin flows, and the formed first and second resin flows in the short side direction In the direction opposite to each other and moved to the relay point B, and the first and second resin flows are guided in directions opposite to each other in the long side direction and moved so as to be laminated in the short side direction at the laminating point C. The cross-sectional shapes in the plane including the short side direction and the long side direction of the laminated first and second resin flows are respectively compressed by a ratio r times in the short side direction, and the compressed first and second resins The flow is merged at a merge point D to form a first merged resin flow, and the formed first merged resin flow is extruded from the base to form a sheet. The positional relationship between the ratio p, the ratio r, the bisection point A, the relay point B, the stacking point C, and the junction point D is expressed by the following relational expression: A method for producing a sheet characterized by satisfying.
1.8 ≦ p ≦ 2.2 and 0.4 ≦ r ≦ 0.6 and 0.9 ≦ L ₃ /H≦4.0 and 0.8 ≦ L ₁ / L ₃ ≦ 1.2 and 0.8 ≦ L ₂ / L ₃ ≦ 1.2
here,
L ₁ : Length in the traveling direction from the bisector A to the relay point B L ₂ : Length in the traveling direction from the relay point B to the stacking point C L ₃ : The junction point from the stacking point C to the junction It is the length in the direction of travel up to D. The sheet manufacturing method according to claim 1, wherein a positional relationship between the stacking point C and the merging point D satisfies the following relational expression.
1.8 ≦ L ₃ /H≦3.0 Resin the first flow path having a rectangular cross section in which the length of the short side in the plane orthogonal to the traveling direction is H, and the length of the long side is the length p multiplied by the length H of the short side. A first flow and a second flow in the long side direction at a half point A to form first and second resin flows, and the formed first and second resin flows in the short side direction In the direction opposite to each other and moved to the relay point B, and the first and second resin flows are guided in directions opposite to each other in the long side direction and moved so as to be laminated in the short side direction at the laminating point C. The cross-sectional shapes in the plane including the short side direction and the long side direction of the arranged first and second resin flows are respectively compressed by a ratio r times in the short side direction, and the compressed first and second resins The flow is merged at a merge point D to form a first merged resin flow, and the formed first merged resin flow is supplied to the die and extruded from the die. And the ratio p, the ratio r, and the positional relationship between the bisection point A, the relay point B, the stacking point C, and the junction point D are as follows: A sheet manufacturing method characterized by satisfying the relational expression:
1.8 ≦ p ≦ 2.2 and 0.4 ≦ r ≦ 0.6 and
0.9 ≦ L ₃ /H≦4.0 and 1.6 ≦ L ₁ / L ₃ and 1.3 ≦ L ₂ / L ₃
Here, L ₁ : Length in the traveling direction from the bisection point A to the relay point B ₂ : Length in the traveling direction from the relay point B to the stacking point C ₃ : From the stacking point C to the above This is the length in the direction of travel to the junction D. 4. The sheet manufacturing method according to claim 3, wherein a positional relationship among the bisector A, the relay point B, the stacking point C, and the joining point D satisfies the following relational expression.
2.26 ≦ L ₃ /H≦3.0 and 2.5 ≦ L ₁ / L ₃ and 2.0 ≦ L ₂ / L ₃ A second flow having a rectangular cross section in which the length of the short side in the plane orthogonal to the traveling direction is H ′, and the length of the long side is a length obtained by multiplying the ratio p ′ by the length H ′ of the short side. The first combined resin flow is caused to flow into the channel, and the resin flow is divided into two in the long side direction at the halves A ′ to form third and fourth resin flows. The fourth resin flow is guided in the opposite direction in the short side direction and moved to the relay point B ′, and the third and fourth resin flows are guided in the opposite direction in the long side direction, and at the stacking point C ′. It is moved so as to be laminated in the short side direction, and the cross-sectional shapes in the plane including the short side direction and the long side direction of the laminated first and second resin flows are respectively compressed by a ratio r ′ times in the short side direction. Then, the compressed second and fourth resin streams are merged at a merge point D ′ to form a second merged resin stream, and the second merged stream formed The sheet manufacturing method according to any one of claims 1 to 4, wherein a resin flow is supplied to the die, wherein the ratio p ', the ratio r', the bisector A ', and the relay point B are provided. The positional relationship between ', the stacking point C', and the confluence point D '
1.8 ≦ p ′ ≦ 2.2 and 0.4 ≦ r ′ ≦ 0.6 and 0.9 ≦ L ′ ₃ /H′≦4.0 and 0.8 ≦ L ′ ₁ / L ′ ₃ ≦ 1 .2 and 0.8 ≦ L ′ ₂ / L ′ ₃ ≦ 1.2
here,
L ′ ₁ : Length in the traveling direction from the bisection point A ′ to the relay point B ′ L ₂ : Length in the traveling direction from the relay point B ′ to the stacking point C ′ ₃ : This is the length in the direction of travel from the stacking point C ′ to the confluence point D ′. Two or more different resin flows are laminated in a short side direction by a feed block to form a resin flow having a layer structure of two or more layers, and the resin flow is caused to flow into the first flow path. The manufacturing method of the sheet | seat in any one of Claims 1-5. 6. The sheet manufacturing method according to claim 1, wherein two different types of resins are allowed to flow into each of the partial flow paths obtained by dividing the first flow path into two in the long side direction. At the bisecting point A, a rectangular cross section having a short side length H in a plane orthogonal to the resin traveling direction and a long side length multiplied by a ratio p to the short side length H A first flow path that is connected to the first flow path at the bisector A, and is formed so as to divide the first flow path into two in the long side direction, and the traveling direction of the resin Along the short side direction to lead to the relay point B, then to the long side direction to lead to the opposite direction to the lamination point C, and then the cross-sectional dimension in the short side direction gradually increases A resin laminating apparatus comprising first and second intermediate flow paths that are compressed and merge at a junction point D whose ratio reaches r times, wherein the ratio p, the ratio r, and the The positional relationship among the bisection point A, the relay point B, the stacking point C, and the junction point D satisfies the following relational expression. Sheet manufacturing apparatus according to claim.
1.8 ≦ p ≦ 2.2 and 0.4 ≦ r ≦ 0.6 and 0.9 ≦ L ₃ /H≦4.0 and 0.8 ≦ L ₁ / L ₃ ≦ 1.2 and 0.8 ≦ L ₂ / L ₃ ≦ 1.2
here,
L ₁ : Length in the traveling direction from the bisector A to the relay point B L ₂ : Length in the traveling direction from the relay point B to the stacking point C L ₃ : The junction point from the stacking point C to the junction It is the length in the direction of travel up to D. 9. The sheet manufacturing apparatus according to claim 8, wherein the following relational expression is satisfied.
1.8 ≦ L ₃ /H≦3.0 At the bisecting point A, a rectangular cross section having a short side length H in a plane orthogonal to the resin traveling direction and a long side length multiplied by the ratio p to the short side length H A first flow path having the first flow path, connected to the first flow path at a half point A, and formed to divide the first flow path into two in the long side direction, and the traveling direction of the resin Along the short side direction to lead to the relay point B, then to the long side direction to lead to the opposite direction to the lamination point C, and then the cross-sectional dimension in the short side direction gradually increases A resin laminating apparatus comprising first and second intermediate flow paths that are compressed and merge at a junction point D whose ratio reaches r times, wherein the ratio p, the ratio r, and the The positional relationship among the bisection point A, the relay point B, the stacking point C, and the junction point D satisfies the following relational expression. Sheet manufacturing apparatus according to claim.
1.8 ≦ p ≦ 2.2 and 0.4 ≦ r ≦ 0.6 and
0.9 ≦ L ₃ /H≦4.0 and 1.6 ≦ L ₁ / L ₃ and 1.3 ≦ L ₂ / L ₃
here,
L ₁ : Length in the traveling direction from the bisector A to the relay point B L ₂ : Length in the traveling direction from the relay point B to the stacking point C L ₃ : The junction point from the stacking point C to the junction It is the length in the direction of travel up to D. 11. The sheet manufacturing apparatus according to claim 10, wherein the following relational expression is satisfied.
2.26 ≦ L ₃ /H≦3.0 and 2.5 ≦ L ₁ / L ₃ and 2.0 ≦ L ₂ / L ₃

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