JP5713604B2 - Method for producing transparent resin laminate, molded article, and resin laminate - Google Patents

Description

  The present invention relates to a method for producing a transparent resin laminate, a molded article, and a resin laminate.

Crystalline resins typified by polypropylene are opaque due to their high crystallinity (crystallinity, crystallization speed, spherulite size, etc.) in ordinary film forming methods. When trying to obtain a transparent crystalline resin film or sheet, for example, as described in Patent Document 1, an additive formulation (nucleating agent) is used to produce a large amount of fine crystals and suppress the growth of spherulites. A polymer design method is generally adopted.
Examples of other means for expressing transparency include a rapid cooling method using a belt process as described in Patent Document 2. In the rapid cooling method using this belt process, transparency is imparted by a film forming process in which polypropylene is sandwiched between a molten state and a belt and a roll kept at a low temperature and rapidly cooled. That is, by rapid cooling, crystal growth is suppressed, low crystallization and fine spherulization are achieved, and higher transparency is realized without adding a nucleating agent.
Moreover, in the polypropylene resin sheet as described in Patent Document 3, high transparency and impact resistance are ensured by adding a specific linear low density polyethylene to polypropylene and quenching.

Japanese Patent No. 3725955 Japanese Patent No. 4237275 JP 2006-297876 A

However, in the polypropylene sheet containing a nucleating agent described in Patent Document 1, although the transparency is improved as compared with the conventional one, the cloudiness is not completely eliminated. For this reason, the further improvement of transparency is desired on the development to the use field | area where further transparency is requested | required.
Polypropylene is originally a crystalline resin, and its viscosity suddenly drops near the melting point, making thermoforming difficult. However, the addition of a nucleating agent increases the crystallinity and further narrows the range of thermoforming. There is a risk that thermoforming will become even more difficult.
In addition, a sheet that has undergone an extrusion film forming and quenching process by a belt process or a water cooling method as described in Patent Document 2 has many spherulites in the vicinity of the sheet surface, and the presence of these spherulites may reduce transparency. is there.
Further, even when a specific linear low density polyethylene is added to polypropylene as described in Patent Document 3, further improvement in transparency is desired.

  An object of this invention is to provide the manufacturing method of a transparent resin laminated body which improves transparency, a molded object, and a resin laminated body.

The inventors' diligent research has revealed that by controlling the stress applied during the extrusion of the resin, the crystal formed by the subsequent rapid cooling is changed. The present invention has been completed based on this finding.
The method for producing a transparent resin laminate according to the present invention comprises an intermediate layer formed of a crystalline resin and a surface layer provided on at least one surface of the intermediate layer and formed of a crystalline resin. The intermediate layer is a propylene-based resin having an isotactic pentad fraction of 85% to 99% and an MFR of 0.5 g / 10 min to 5.0 g / 10 min. Resin (a) 80% by mass to 99.5% by mass and manufactured using a metallocene catalyst, density is 898 kg / m ³ or more and 913 kg / m ³ or less, MFR is 0.5 g / 10 min or more and 6.0 g / The metallocene ethylene-α-olefin copolymer (b) of 10% or less and 0.5% by mass or more and 20% by mass or less, and the crystalline resin of the surface layer has a crystallinity that forms the intermediate layer. Compared to resin, Belt Flow Rate (Melt Flow Rate: hereinafter referred to as MFR) is large, is intended relaxation time is short, the melt and the crystalline resin to form a pre-Symbol intermediate layer, a crystalline resin forming the surface layer, respectively Then, the resin laminate is formed by cooling in a state of being extruded and laminated in a sheet form, and the resin laminate is heat-treated at a temperature not lower than the crystallization temperature and not higher than the melting point.

In the present invention, it is preferable that the crystalline resins forming the intermediate layer and the surface layer are both propylene resins.
In the present invention, the metallocene ethylene-α-olefin copolymer is preferably a linear low density polyethylene.
Moreover, in this invention, it is preferable to set it as the structure which provides the said intermediate | middle layer on both surfaces of the base material layer formed with crystalline resin, and provides the said surface layer on the surface of this intermediate | middle layer.
In the present invention, the crystalline resin forming the base material layer is preferably a propylene resin.

Molded article according to the present invention is a molded article comprising an intermediate layer formed by a crystalline resin, and the surface layer formed by the crystalline resin provided on at least one surface of the intermediate layer, the said The intermediate layer has a propylene resin (a) having an isotactic pentad fraction of 85% to 99% and an MFR of 0.5 g / 10 min to 5.0 g / 10 min. % Of metallocene-based ethylene-α-olefin copolymer having a density of 898 kg / m ^{3 to} 913 kg / m ³ and an MFR of 0.5 g / 10 min to 6.0 g / 10 min. The polymer (b) is formed from 0.5% by mass or more and 20% by mass or less, and the crystalline resin of the surface layer has a melt flow rate (Melt Flow Rate) as compared with the crystalline resin forming the intermediate layer. : M Referred to as R) is large, is intended relaxation time is short, and the crystalline resin forming the pre Symbol intermediate layer, a crystalline resin forming the surface layer, is quenched stacked into a sheet in a molten state The obtained resin laminate is thermoformed at a temperature not lower than the crystallization temperature and not higher than the melting point.

The resin laminate according to the present invention is a resin laminate in which a transparent resin laminate is formed by heat treatment, and is provided on at least one surface of the intermediate layer formed of a crystalline resin. A surface layer formed of a crystalline resin, wherein the crystalline resin of the intermediate layer has an isotactic pentad fraction of 85% to 99% and an MFR of 0.5 g / 10 min to 5%. Propylene resin (a) of 0.0 g / 10 min or less and 80% by mass or more and 99.5% by mass or less, produced using a metallocene catalyst, a density of 898 kg / m ³ or more and 913 kg / m ³ or less, and an MFR of 0.00. 5 g / 10 min to 6.0 g / 10 min metallocene ethylene-α-olefin copolymer (b) 0.5 mass% to 20 mass%, and the crystalline resin of the surface layer is Forming the intermediate layer Large MFR is compared to-crystalline resin, and wherein the relaxation time is short.

  And in this invention, it is preferable to set it as the structure which provides the said intermediate | middle layer on both surfaces of the base material layer formed with crystalline resin, and provides the said surface layer on both surfaces of this intermediate | middle layer.

In the present invention, a surface layer is formed of a crystalline resin intermediate layer and a crystalline resin having a melt flow rate larger than that of the crystalline resin forming the intermediate layer and a short relaxation time on at least one surface of the intermediate layer. To do. Further, at least one of the intermediate layer and the surface layer contains a metallocene ethylene-α-olefin copolymer produced using a metallocene catalyst.
For this reason, the stress applied when extruded into a sheet is relieved by the surface layer, and the residual stress that causes the formation of spherulites that are likely to be generated at a certain depth from the surface is reduced.
However, since the generation of spherulites cannot be suppressed only by reducing the residual stress, the formation and growth of spherulites can be achieved by including a metallocene ethylene-α-olefin copolymer at a position where the spherulites are generated. Is suppressed, and the amount of spherulites decreases and the size of spherulites decreases. Therefore, light scattering by spherulites is reduced, and transparency can be improved (haze reduction).
Then, the respective crystalline resins are cooled in a molten state and laminated in the form of an extruded sheet to form a resin laminate, and the resin laminate is heat-treated at a temperature not lower than the crystallization temperature and not higher than the melting point.
In the heat treatment of the quenching sheet, since the crystallization is maintained while maintaining the fine higher order structure in the resin laminate of good crystallinity obtained by cooling, there is no inconvenience to be damaged, and it can be formed into a good sheet shape, A highly transparent sheet-like transparent resin laminate is obtained.

Schematic which shows the manufacturing apparatus which manufactures the transparent resin laminated body concerning one Embodiment in the manufacturing method of the transparent resin laminated body of this invention. Schematic which shows the taking-in part in the said manufacturing apparatus. In the graph which shows the relationship between the refractive index and density of the polypropylene sheet for demonstrating this invention, a horizontal axis is a density and a vertical axis | shaft is a refractive index.

Hereinafter, the manufacturing method of the transparent resin laminated body concerning one Embodiment of this invention is demonstrated with reference to FIG.
In this embodiment, the transparent resin laminate is exemplified by a polypropylene sheet-like transparent resin laminate, but is not limited thereto. For example, crystalline resins other than various polypropylenes can be used, and heat molding into containers and the like can also be targeted.

[Configuration of manufacturing equipment]
In FIG. 1, a manufacturing apparatus 1 includes an original sheet forming apparatus 10 that melts and kneads a raw material resin, extrudes it into a sheet shape, and rapidly cools, and an original sheet as a resin laminate manufactured by the original sheet forming apparatus 10. And a heat treatment apparatus 20 for producing the transparent resin laminate 3 by heat-treating the sheet 2 (see FIG. 2).
Here, although the details will be described later, the raw sheet 2 has a two-type three-layer structure in which surface layers 2B are provided on both surfaces of a sheet-like intermediate layer 2A as shown in FIG.

The raw sheet forming apparatus 10 includes a T-die extrusion apparatus 100 and a cooling press apparatus 110.
The T die extrusion apparatus 100 includes an extruder 101 and a T die 102.
As the extruder 101, for example, a single-screw extruder or a multi-screw extruder is used. A plurality of extruders 101 are provided, one corresponding to the intermediate layer 2A of the original fabric sheet 2 and one corresponding to the surface layer 2B.
The T die 102 is detachably attached to the tip of each extruder 101, and is molded in a state where the molten resin 2C extruded from the extruder 101 is laminated in a sheet shape. Examples of the T die 102 include a coat hanger die and a slot die. The T die 102 is not limited to a coat hanger die and a slot die as long as the die can form a multilayer sheet. Moreover, as a structure which laminates | stacks the raw material resin fuse | melted from the extruder, a feed block system or a multi manifold die system can be illustrated, for example.

The cooling and pressing device 110 of the raw sheet forming apparatus 10 press-molds the molten resin 2C laminated and extruded into a sheet shape by the T-die 102 onto the original sheet 2 while cooling. As shown in FIGS. 1 and 2, the cooling pressing device 110 includes a first cooling roll 111, a second cooling roll 112, a third cooling roll 113, a fourth cooling roll 114, a cooling endless belt 115, and cooling water spraying. The nozzle 116, the water tank 117, the water absorption roll 118, and the peeling roll 119 are provided.
The 1st cooling roll 111, the 2nd cooling roll 112, the 3rd cooling roll 113, and the 4th cooling roll 114 are the metal rolls of the material excellent in thermal conductivity supported rotatably. And at least any one of the 1st cooling roll 111, the 3rd cooling roll 113, and the 4th cooling roll 114 is connected with the rotation drive means which is not shown in figure, and the drive of a rotation drive means Is rotated by.
The first cooling roll 111, the second cooling roll 112, the third cooling roll 113, and the fourth cooling roll 114 preferably have a larger diameter in terms of durability of the cooling endless belt 115, and are practically particularly diameters. Is designed to be 100 to 1500 mm.

The circumferential surface of the first cooling roll 111 is covered with an elastic material 111A. As the elastic member, for example, nitrile-butadiene rubber (NBR), fluorine rubber, polysiloxane rubber, EPDM (ethylene-propylene-diene copolymer), or the like is used.
The elastic material 111A preferably has, for example, a hardness (measured by a method based on JIS K 6301A) of 80 degrees or less and a thickness of about 10 mm in order to obtain an excellent surface pressure by elastic deformation.

The second cooling roll 112 is a metal roll (mirror surface) having a mirror surface with a surface roughness of the peripheral surface (surface roughness: Rmax based on JIS B 0601 “surface roughness—definition and indication”) of 0.3 μm or less. Cooling roll). Inside the second cooling roll 112, a cooling means such as a water-cooling type (not shown) is built in in order to allow the surface temperature to be adjusted. This is because if the surface roughness (Rmax) of the second cooling roll 112 exceeds 0.3 μm, the glossiness and transparency of the obtained raw sheet 2 may be lowered.
Such a second cooling roll 112 includes an intermediate layer 2A melt-extruded from the T die 102 and the first cooling roll 111 via a metal endless belt 115 made of stainless steel and the like. It arrange | positions so that the surface layer 2B may be pinched | interposed.

The cooling endless belt 115 is formed in an endless belt shape, for example, of stainless steel, carbon steel, titanium alloy or the like, and is wound around the first cooling roll 111, the third cooling roll 113, and the fourth cooling roll 114. Yes. This cooling endless belt 115 is formed in a mirror surface having an outer peripheral surface, that is, a surface roughness (Rmax) of a surface in contact with the intermediate layer 2A and the surface layer 2B melt-extruded from the T-die 102 is 0.3 μm or less.
The third cooling roll 113 and the fourth cooling roll 114 can be adjusted in the temperature of the cooling endless belt 115 by incorporating cooling means such as a water cooling type (not shown) inside.

The cooling water spray nozzle 116 is positioned below the second cooling roll 112 in the vertical direction, and is disposed in a state in which the cooling water 116 </ b> A is sprayed to the back surface of the cooling endless belt 115.
The cooling water spray nozzle 116 rapidly cools the cooling endless belt 115 by spraying the cooling water 116 </ b> A, and the intermediate layer 2 </ b> A and the surface layer 2 </ b> B that are press-contacted by the first cooling roll 111 and the second cooling roll 112. Even cool down.

The water tank 117 is formed in a box shape having an open upper surface, is provided so as to cover the entire lower surface of the second cooling roll 112, and collects the cooling water 116A sprayed on the back surface of the cooling endless belt 115.
The water tank 117 is provided with a drain port 117B through which the collected water 117A is discharged from the lower surface of the water tank 117.

The water absorption roll 118 is installed on the side surface portion of the second cooling roll 112 on the third cooling roll 113 side so as to be in contact with the cooling endless belt 115.
The water absorption roll 118 is for removing excess cooling water adhering to the back surface of the endless belt 115 for cooling.

The peeling roll 119 is disposed so as to guide the intermediate layer 2A and the surface layer 2B to the third cooling roll 113 and the cooling endless belt 115, and the raw sheet 2 after cooling is removed from the cooling endless belt 115. It peels off.
The peeling roll 119 may be disposed so that the original sheet 2 is pressed against the third cooling roll 113 side. However, as shown in FIG. It is preferable that the sheet 2 is not pressed.

The heat treatment apparatus 20 of the manufacturing apparatus 1 includes a preheating apparatus 210, a heat treatment apparatus main body 220, and a cooling apparatus 230.
The preheating device 210 heats and preheats the original fabric sheet 2 formed by the original fabric sheet forming apparatus 10. As shown in FIG. 1, the preheating device 210 includes a first preheating roll 211, a second preheating roll 212, and a third preheating roll 213. The first preheating roll 211, the second preheating roll 212, and the third preheating roll 213 are made of a material having excellent thermal conductivity such as metal.
The first preheating roll 211, the second preheating roll 212, and the third preheating roll 213 are provided with temperature adjusting means (not shown) such as a steam heating type that enables temperature adjustment of the surface. The temperature adjusting means is not limited to the configuration directly provided on each of the preheating rolls 211 to 213, and a separate preheating roll may be provided, or a preheating device provided externally may be used.
Note that the preheating device 210 is not limited to the configuration in which these three preheating rolls 211 to 213 are disposed, and the raw sheet 2 such as a configuration in which one or a plurality of preheating rolls are provided or a configuration in which an endless belt is used. Any configuration capable of preheating is possible.

The heat treatment apparatus main body 220 of the heat treatment apparatus 20 travels while heating the raw fabric sheet 2 preheated by the preheating apparatus 210. The heat treatment apparatus main body 220 includes a first heating roll 221, a second heating roll 222, a third heating roll 223, a fourth heating roll 224, a rubber roll 225 that is a pressure roll, a guide roll 226, A metal heating endless belt 227 and driving means (not shown) are provided.
The first heating roll 221, the second heating roll 222, the third heating roll 223, the fourth heating roll 224, and the guide roll 226 are made of a material having excellent thermal conductivity such as metal. The first heating roll 221, the second heating roll 222, the third heating roll 223, and the fourth heating roll 224 are preferably larger in diameter in terms of durability of the metal heating endless belt 227. In particular, those designed to have a diameter of 100 to 1500 mm are preferable.
The first heating roll 221, the second heating roll 222, the third heating roll 223, and the fourth heating roll 224 are provided with temperature adjusting means (not shown) such as a steam heating type that enables temperature adjustment of the surface. . Note that the temperature adjusting means is not limited to the configuration directly provided on each of the heating rolls 221 to 224, and a separate heating dedicated roll may be provided, or a configuration in which heating is performed by an external heating device may be employed.
The heating condition is a temperature not lower than the crystallization temperature of the raw fabric sheet 2 and not higher than the melting point, for example, from the propylene-based resin (a) and the metallocene-based ethylene-α-olefin copolymer (b). In such a case, it is a condition that the surface temperature of the raw fabric sheet 2 is 120 ° C. or higher and lower than the melting point.
The driving means is connected to at least one of the first heating roll 221, the second heating roll 222, and the third heating roll 223. And a drive means rotates at least any one of the 1st heating roll 221, the 2nd heating roll 222, and the 3rd heating roll 223 connected by the drive.

The heating endless belt 227 is formed in an endless belt shape, for example, of stainless steel, carbon steel, titanium alloy, or the like. In addition, although a thickness dimension can be set arbitrarily, 0.3 mm or more is preferable in strength.
The heating endless belt 227 is stretched over the first heating roll 221, the second heating roll 222, and the third heating roll 223, and is rotated by driving of the driving means. The driving means is driven and controlled so that the moving speed of the heating endless belt 227 is substantially the same as the moving speed of the cooling endless belt 115 that is rotated by driving the driving means of the cooling pressing device 110 described above. .

  The fourth heating roll 224 is arranged in a state where the outer peripheral surface faces the outer peripheral surface of the heating endless belt 227 and intersects the outer tangent line of the first heating roll 221 and the second heating roll 222. The fourth heating roll 224 is rotatably arranged between the outer peripheral surface of the fourth heating roll 224 and the outer peripheral surface of the heating endless belt 227 so that the raw sheet 2 preheated by the preheating device 210 can be introduced. It is installed.

The rubber roll 225 is opposed to the outer peripheral surface of the heating endless belt 227 in a portion where the outer peripheral surface is wound around the first heating roll 221.
The rubber roll 225 is formed by covering a cushion material (not shown) on at least the outer peripheral surface. This cushion material is made of the same material as the second cooling roll 112 of the cooling and pressing device 110. In addition, the rubber roll 225 can be formed by covering a cushion material over substantially the entire outer peripheral surface or by forming a cushion material over almost the whole.
Then, the rubber roll 225 presses the raw fabric sheet 2 from the preheating device 210 against the outer peripheral surface of the heating endless belt 227 so as to be in thermal contact therewith. That is, the rubber roll 225 is disposed in contact with the first heating roll 221 through the preheated raw sheet 2 and the heating endless belt 227. The raw sheet 2 travels in close contact with the heating endless belt 227, and then travels while being pressed and clamped by the fourth heating roll 224.

The guide roll 226 has a sheet-like transparency whose outer peripheral surface is rotatably disposed so as to face the outer peripheral surface of the heating endless belt 227 and is heated and pressed between the heating endless belt 227 and the fourth heating roll 224. The resin laminate 3 is guided. That is, the guide roll 226 is disposed on the production downstream side of the fourth heating roll 224 via the second heating roll 222 located on the production downstream side that is the downstream side in the moving direction of the transparent resin laminate 3. Has been.
As a result, the guide roll 226 peeled off the transparent resin laminate 3 obtained by heating and pressing between the heating endless belt 227 and the fourth heating roll 224 from the outer peripheral surface of the fourth heating roll 224. Later, the guide is performed so as to peel from the outer peripheral surface of the heating endless belt 227.

The cooling device 230 of the heat treatment apparatus 20 cools the transparent resin laminate 3 that has been heat treated by the heat treatment apparatus main body 220. The cooling device 230 includes a first cooling guide roll 231, a second cooling guide roll 232, and a pair of guide rolls 233. The first cooling guide roll 231, the second cooling guide roll 232, and the pair of guide rolls 233 are made of a material having excellent thermal conductivity such as metal.
The first cooling guide roll 231, the second cooling guide roll 232, and the pair of guide rolls 233 are positioned substantially linearly in a state where the transparent resin laminate 3 that has been heat-treated in the heat treatment apparatus main body 220 is wound in a meandering manner. Arranged. The first cooling guide roll 231 and the second cooling guide roll 232 are provided with temperature adjusting means (not shown) such as a steam heating type that enables temperature adjustment of the surface. The temperature adjusting means is not limited to the configuration directly provided on each of the cooling guide rolls 231 and 232, and a separate cooling dedicated roll may be provided, or cooling may be performed by a cooling device provided outside.
In addition, the pair of guide rolls 233 are disposed on the production downstream side of the second cooling guide roll 232. These guide rolls 233 are arranged in the vertical direction intersecting with the moving direction of the transparent resin laminate 3 so that the transparent resin laminate 3 sandwiched between the outer peripheral surfaces facing each other and cooled between the outer peripheral surfaces. It is installed.
The cooling device 230 is not limited to the configuration in which the first cooling guide roll 231, the second cooling guide roll 232, and the pair of guide rolls 233 are provided, and a configuration in which one or a plurality of rolls are provided or an endless configuration Any configuration capable of cooling the transparent resin laminate 3 such as a configuration using a belt can be used.

[Composition of the original fabric sheet]
Next, the structure of the original fabric sheet 2 which manufactures a transparent resin laminated body with the said manufacturing apparatus 1 is demonstrated.
The raw sheet 2 has, for example, a two-type three-layer structure in which surface layers 2B are provided on both surfaces of a sheet-like intermediate layer 2A.
The intermediate layer 2A is formed of a crystalline resin, for example, a polypropylene resin. In particular, the intermediate layer 2A is preferably formed of a polypropylene resin mainly composed of a propylene resin (a) and a metallocene ethylene-α-olefin copolymer (b).

The propylene resin (a) has an isotactic pentad fraction of 85% to 99% and a melt flow rate (hereinafter referred to as MFR) of 0.5 g / 10 min to 5.0 g / 10. Preferably it is less than or equal to minutes. Furthermore, it is more preferable that the isotactic pentad fraction is 90% or more and 99% or less and the MFR is 2.0 g / 10 min to 4.0 g / 10 min.
Here, the isotactic pentad fraction is an isotactic fraction in pentad units (one in which five propylene monomers are isotactically bonded) in the molecular chain of the resin composition. This method for measuring the fraction is described in, for example, Macromolecules, Vol. 8 (1975), p. 687, and can be measured by ¹³ C-NMR.
Moreover, about the measurement of MFR, based on JIS-K7210, it can measure with the measurement temperature of 230 degreeC, and the load of 2.16kg.

When the isotactic pentad fraction of the propylene-based resin (a) is lower than 85%, the molded product may have insufficient rigidity. On the other hand, if the isotactic pentad fraction is higher than 99%, the transparency may be lowered. For this reason, it is preferable that propylene-type resin (a) sets an isotactic pentad fraction to 85% or more and 99% or less.
In addition, when the MFR of the propylene resin (a) is less than 0.5 g / 10 min, shear stress at the die slip portion at the time of extrusion molding becomes strong, which may promote crystallization and decrease transparency. is there. On the other hand, if MFR is greater than 5.0 g / 10 min, drawdown may increase during thermoforming, and moldability may be reduced. For this reason, it is preferable that propylene-type resin (a) sets MFR to 0.5 g / 10min or more and 5.0 g / 10min or less.

On the other hand, the metallocene ethylene-α-olefin copolymer (b) is produced using a metallocene catalyst, has a density of 898 kg / m ³ or more and 913 kg / m ³ or less, and an MFR of 0.5 g / 10 min or more and 6.0 g. / 10 minutes or less.
Here, the density was measured at a test temperature of 23 ° C. in accordance with “Measurement method of density and specific gravity of plastic-non-foamed plastic” of JIS-K7112.
The MFR can be measured according to JIS-K7210 at a measurement temperature of 190 ° C. and a load of 2.16 kg.
The metallocene ethylene-α-olefin copolymer (b) is preferably a material having a refractive index substantially the same as that of the propylene resin, particularly a linear low density polyethylene.
If the density of the metallocene ethylene-α-olefin copolymer (b) is less than 898 kg / m ³ or greater than 913 kg / m ³ , the refractive index of the matrix propylene resin (a) will not match. The refraction of light may increase at the interface between the propylene resin (a) and the metallocene ethylene-α-olefin copolymer (b), thereby impairing transparency.
That is, if the refractive indexes of the propylene resin (a) and the metallocene ethylene-α-olefin copolymer (b) are substantially the same, the transparency of the produced transparent resin laminate 3 is improved.

FIG. 3 is a graph showing the relationship between the refractive index and density of a polypropylene sheet formed into a sheet by rapid cooling and crystallized by heat treatment. Referring to FIG. 3, when a rapidly cooled polypropylene sheet is crystallized by heat treatment, the refractive index is 1.504 to 1.509 and the density is in the range of 900 to 907 kg / m ³ . Therefore, if the refractive index of the metallocene ethylene-α-olefin copolymer (b) to be added is in the range of 1.504 to 1.509, the transparency is not impaired.
Here, the relationship between the refractive index and the density of the substance can be expressed by the Lorentz-Lorenz equation shown in the following equation (1). n is the refractive index of the target substance, ρ is the density of the target substance, M is the molecular weight of the target substance, N is the Avogadro number, and P is the polarizability of the target substance.

  Since Avogadro's number N, polarizability P, and molecular weight M are constants, the refractive index n can be expressed by the following formula (2) using the density ρ as a parameter.

As shown in the above formula (2), since the density and the refractive index are correlated, the metallocene ethylene-α-olefin copolymer (b) can be selected by density.
Therefore, the density of the metallocene ethylene-α-olefin copolymer (b) is preferably set to 898 kg / m ³ or more and 913 kg / m ³ or less.
In addition, when the metallocene ethylene-α-olefin copolymer (b) has an MFR of less than 0.5 g / 10 min, it becomes difficult to disperse the matrix in the molecule of the propylene resin (a), and the metallocene copolymer (b) There is a possibility that the dispersion diameter of the ethylene-α-olefin copolymer (b) becomes large, light scattering occurs, and transparency is impaired. On the other hand, if the MFR is larger than 6.0 g / 10 minutes, the compatibility with the propylene resin (a) of the matrix deteriorates, and the metallocene ethylene-α-olefin copolymer (b) cannot be dispersed completely and becomes enormous. It will exist as particles. In such a state, light scattering occurs due to the particles of the metallocene-based ethylene-α-olefin copolymer (b), and transparency may be impaired.

When various polymer blends are kneaded to an equilibrium state, the dispersed phase diameter D of the blend can be expressed by the Wu formula shown in the following formula (3). Here, D is the dispersed phase diameter, γ is the interfacial tension, η _m is the viscosity of the matrix, G is the shear rate, and η _d is the dispersed phase viscosity.

Since the viscosity η _{m of} the matrix and the shear rate G are constant, the dispersed phase diameter D has parameters of the dispersed phase viscosity η _d and the interfacial tension γ. As shown in the above formula (3), it can be seen that as the viscosity of the matrix and the dispersed phase approaches 1, the dispersed phase diameter D becomes smaller, light scattering is reduced, and transparency is improved. In the present invention, good transparency was exhibited when the viscosity ratio at a shear rate of 60 sec ⁻¹ was 1.0 to 3.0. The MFR of the metallocene ethylene-α-olefin copolymer (b) falling within the above viscosity range is 0.5 g / 10 min or more and 6.0 g / 10 min.

And 2 A of intermediate | middle layers are mix | blended by propylene-type resin (a) 80 mass% or more and 99.5 mass% or less, metallocene system ethylene-alpha-olefin copolymer (b) 0.5 mass% or more and 20 mass% or less. It is preferable.
That is, when the compounding amount of the metallocene ethylene-α-olefin copolymer (b) increases, the rigidity of the obtained raw sheet 2 may be lowered. On the other hand, when the blending amount of the metallocene ethylene-α-olefin copolymer (b) is reduced, the metallocene ethylene-α-olefin copolymer (b) is not sufficiently dispersed in the propylene resin (a), This is because the suppression of the growth of spherulites becomes insufficient and it becomes difficult to improve the transparency.

  On the other hand, the surface layer 2B is formed of a crystalline resin such as a polypropylene resin having a higher melt flow rate (hereinafter referred to as MFR) and a shorter relaxation time than the intermediate layer 2A. Specifically, the surface layer 2B preferably has an MFR 1.5 times or more larger than that of the intermediate layer 2A. This is because if the MFR is less than 1.5 times, the effect of improving transparency is small. Furthermore, the relaxation time is preferably 80% or less of the intermediate layer 2A. This is because if the relaxation time is greater than 80%, the effect of improving transparency is small.

About the measurement of MFR, based on JIS-K7210, it measured with the measurement temperature of 230 degreeC, and the load of 2.16kg.
The relaxation time (τ) is the angular frequency when a frequency dispersion measurement is performed at a temperature of 175 ° C. with a cone plate of 25 mmφ, a cone angle of 0.1 radians (rad) in a rotational rheometer manufactured by Rheometrics. The relaxation time at ω = 0.01 rad / sec was determined. Specifically, the complex elastic modulus G ^* (iω) measured for the resin pellet is defined as σ ^* / γ ^* by stress σ ^* and strain γ ^* as shown in the following formula (4), and the relaxation time τ is It calculated | required by following formula (5).
[Formula (4)]
G ^* (iω) = σ ^* / γ ^* = G ′ (ω) + IG ”(ω) (4)
[Formula (5)]
τ (ω) = G '(ω) / (ωG "(ω)) (5)
(In the formula, G ′ represents the storage elastic modulus, and G ″ represents the loss elastic modulus.)

Here, the relaxation time (τ) will be described in detail.
When an external force is applied to a material system in an equilibrium state, and after reaching a new equilibrium state or steady state, when the external force is removed, the phenomenon that the system recovers to the initial equilibrium state by the internal motion of the system is called a relaxation phenomenon. A characteristic time constant that is a measure of the time required for relaxation is called relaxation time. In the case of a polymer molding process (for example, extrusion molding), a molten polymer is flowed. At this time, molecular chains are stretched in the flow direction and aligned (oriented). When the flow is finished and the cooling is started, the stress applied to the molecule disappears, each molecular chain starts to move, and eventually turns in a selfish direction (this is called relaxation of the molecular chain).
The relaxation time is related to the ease of return of the molecular chain oriented in the extrusion direction during extrusion, and indicates that when the relaxation time is short, it returns easily.

In addition, in this embodiment, although the raw fabric sheet 2 was made into three layers, it is not restricted to this, It is good also as two layers which formed the surface layer 2B only on the single side | surface of 2 A of intermediate | middle layers. Moreover, the raw fabric sheet 2 is good also as three or more layers which provided the intermediate | middle layer 2A in the at least one surface of the base material layer, and provided the surface layer 2B in the surface of the intermediate | middle layer 2A.
Moreover, as a resin raw material, it is not restricted to a polypropylene resin.

[Method for producing transparent resin laminate]
Next, the operation of manufacturing the sheet-like transparent resin laminate 3 by the manufacturing apparatus 1 will be described.

First, temperature adjusting means so that the outer peripheral surface temperatures of the cooling endless belt 115 and the third cooling roll 113 of the cooling and pressing device 110 of the raw sheet forming apparatus 10 are maintained at the dew point of the molten resin 2C or more and 50 ° C. or less. Control the temperature with. Here, when the temperature exceeds 50 ° C., good transparency of the raw fabric sheet 2 cannot be obtained, and there is a possibility that α-crystals increase and thermoforming becomes difficult. For this reason, it controls to 50 degrees C or less, Preferably it is 30 degrees C or less. If the dew point is lower than the dew point, condensation may occur on the surface and water droplets may occur on the sheet, making it difficult to form a uniform film.
Further, in the heat treatment apparatus main body 220 of the heat treatment apparatus 20, temperature adjusting means is used so that the outer peripheral surface temperature of the heating endless belt 227 or the fourth heating roll 224 is maintained at the crystallization temperature of the raw sheet 2 or more and the melting point or less. Control the temperature with. In the preheating device 210 of the heat treatment apparatus 20, the temperature may be controlled so as to preheat to 50 ° C. or more and the crystallization temperature or less, which is the temperature cooled by the cooling and pressing device 110 of the raw sheet forming apparatus 10.

In this state, from the T die 102 of the T die extrusion device 100, the molten resin 2C of the intermediate layer 2A and the surface layer 2B is extruded in a state of being laminated in a sheet shape, and the cooling endless belt 115 that the cooling pressing device 110 rotates and It is introduced between the outer peripheral surfaces of the rotating third cooling roll 113.
The introduced molten resin 2C laminated in the form of a sheet of the intermediate layer 2A and the surface layer 2B is subjected to surface pressure contact and rapidly cooled.
During the rapid cooling, the elastic material 111A is elastically deformed by a pressing force between the second cooling roll 112 and the third cooling roll 113. The molten resin 2C is held together with the cooling endless belt 115 at an angle θ1 portion (see FIG. 2) from the center of the second cooling roll 112 and the third cooling roll 113 where the elastic material 111A is elastically deformed. The surface is pressed by the restoring force of the elastic material 111A.
In this case, the surface pressure is preferably 0.1 MPa or more and 20.0 MPa or less. Here, if the surface pressure is lower than 0.1 MPa, air may be caught between the cooling endless belt 115, the third cooling roll 113, and the molten resin 2C, and the sheet appearance may be poor. On the other hand, when the surface pressure is higher than 20.0 MPa, it is not preferable from the viewpoint of the life of the endless belt 115 for cooling. For this reason, the surface pressure of the planar pressing is set to 0.1 MPa or more and 20.0 MPa or less.

Subsequently, the intermediate layer 2 </ b> A and the surface layer 2 </ b> B sandwiched between the second cooling roll 112 and the cooling endless belt 115 are arranged in the second cooling roll at the arc portion corresponding to the substantially lower half circumference of the second cooling roll 112. The sheet 112 is press-contacted by the roll 112 and the endless belt 115 for cooling. Further, the intermediate layer 2 </ b> A and the surface layer 2 </ b> B are further rapidly cooled by spraying the cooling water 116 </ b> A onto the back side of the cooling endless belt 115 by the cooling water spray nozzle 116.
In addition, it is preferable to set the surface pressure at this time to 0.01 MPa or more and 0.5 MPa or less. Further, the temperature of the cooling water 116A is preferably set to 0 ° C. or higher and 30 ° C. or lower. The sprayed cooling water 116A is collected in the water tank 117, and the collected water 117A is discharged from the drain port 117B.
Here, if the surface pressure is lower than 0.01 MPa, meandering control of the endless belt 115 for cooling becomes difficult, and stable production may not be possible. On the other hand, when the surface pressure is higher than 0.5 MPa, the tension acting on the cooling endless belt 115 is increased, which is not preferable from the viewpoint of life. For this reason, it is preferable to set the surface pressure of the planar pressure to 0.01 MPa or more and 0.5 MPa or less.

In this way, after the surface cooling and the intermediate layer 2A and the surface layer 2B are pressed between the second cooling roll 112 and the cooling endless belt 115, they are in close contact with the cooling endless belt 115. The intermediate layer 2 </ b> A and the surface layer 2 </ b> B are moved onto the third cooling roll 113 along with the rotational movement of the cooling endless belt 115. The intermediate layer 2 </ b> A and the surface layer 2 </ b> B guided by the peeling roll 119 are cooled by the third cooling roll 113 via the cooling endless belt 115.
In addition, the water adhering to the back surface of the endless belt 115 for cooling is removed by the water absorption roll 118 provided in the middle of the movement from the second cooling roll 112 to the third cooling roll 113.

The intermediate layer 2A and the surface layer 2B cooled on the third cooling roll 113 are peeled off from the cooling endless belt 115 by the peeling roll 119, and the raw fabric sheet 2 is formed.
The obtained raw sheet 2 has an internal haze of 20% or less and a surface roughness of at least one surface of Rmax = 0.5 μm or less. That is, in the cooling and pressing device 110, it is preferable that the inner haze is 20% or less and at least one surface has a surface roughness of Rmax = 0.5 μm or less so that the raw sheet 2 is obtained by rapid cooling and surface pressure contact.
Here, haze (cloudiness) is based on JIS-K-7105, the total light transmittance (Tt) showing the total amount of the light which permeate | transmitted and irradiated the original fabric sheet 2, and the original fabric sheet 2 Is obtained by the following formula (6) based on the ratio to the diffused light transmittance (Td) that is diffused by the transmitted light. The total light transmittance (Tt) is the sum of the parallel light transmittance (Tp) and the diffused light transmittance (Td) that are transmitted coaxially with the incident light.
[Formula (6)]
Haze (H) = (Td / Tt) × 100 (6)

Further, the internal haze is a value obtained by measuring the haze by applying silicone to the sheet surface in order to measure the transparency inside the sheet without being affected by the sheet surface roughness. Here, when the value of the internal haze is larger than 20%, the internal haze is increased even when the heat treatment by the heat treatment apparatus main body 220 and the surface pressing process are performed in the latter stage, and the highly transparent transparent resin laminate 3 is formed. There is a risk that it will not be obtained.
On the other hand, if the surface roughness is rougher than Rmax = 0.5 μm, there is a possibility that so-called blisters may be generated by entraining air when thermally contacting the fourth heating roll 224 and the heating endless belt 227 in the heat treatment apparatus main body 220 in the latter stage. is there. For this reason, it is preferable to mold the raw sheet 2 so that the internal haze is 20% or less and the surface roughness is Rmax = 0.5 μm or less.

Next, the raw sheet 2 formed by the cooling and pressing device 110 is moved over the outer peripheral surfaces of the first preheating roll 211, the second preheating roll 212, and the third preheating roll 213 of the preheating device 210, and preheated. To do.
Then, the raw fabric sheet 2 preheated by the preheating device 210 is introduced between the outer peripheral surfaces of the rubber roll 225 and the heating endless belt 227 of the heat treatment device main body 220. The introduced raw sheet 2 is pressed into a sheet shape and thermally adhered to the outer peripheral surface of the heating endless belt 227 by the rubber roll 225. The heat-sealed original fabric sheet 2 is moved together with the rotating endless belt 227 for rotation and introduced between the outer peripheral surfaces of the endless belt 227 for heating and the fourth heating roll 224. The introduced original sheet 2 is brought into surface contact with the fourth heating roll 224 with the original sheet 2 interposed therebetween and the heating endless belt 227 to which tension is applied by the fourth heating roll 224.
The heating temperature in the heat treatment of the original fabric sheet 2 is not less than the crystallization temperature of the original fabric sheet 2 and not more than the melting point. For example, when the raw sheet 2 is made of the above-described propylene resin (a) and metallocene ethylene-α-olefin copolymer (b), the surface temperature of the raw sheet 2 is 120 ° C. or higher and lower than the melting point. It heats with the condition which becomes. Moreover, the surface pressure at the time of heat processing is suitably set according to the shape to shape | mold.
Here, at a temperature lower than the crystallization temperature of the original fabric sheet 2, the original fabric sheet 2 is insufficiently softened and cannot be formed into a desired shape. On the other hand, at a temperature higher than the melting point of the raw sheet 2, the higher order structure obtained by the rapid cooling in the cooling and pressing device 110 is destroyed and becomes cloudy and cannot obtain transparency.
Thereafter, the original sheet 2 is peeled off from the outer peripheral surface of the fourth heating roll 224 and heated while being moved in close contact with the heating endless belt 227. The heated original fabric sheet 2 is peeled off from the heating endless belt 227 by the guide of the guide roll 226 and fed out as a sheet-like transparent resin laminate 3.

The obtained transparent resin laminate 3 is cooled by moving so as to meander over the outer peripheral surfaces of the first cooling guide roll 231 and the second cooling guide roll 232 of the cooling device 230, and a pair of guide rolls Send out between 233.
In addition, the transparent resin laminated body 3 which is the delivered product is wound up, for example, by a winding device (not shown).

The total thickness of the transparent resin laminate 3 obtained by the above production method is preferably 160 μm or more and less than 500 μm.
Here, when the total thickness dimension of the transparent resin laminated body 3 is thinner than 160 μm, the quenching effect by the cooling rolls 111 to 114 of the cooling press device 110 is sufficiently obtained, and it is transparent to the extent that there is no need to dare to laminate. This is because the sex is obtained. On the other hand, when the total thickness dimension of the transparent resin laminate 3 is 500 μm or more, the rapid cooling effect due to heat conduction cannot be expected, and as a result, the lamination effect cannot be expressed.

[Effects of Embodiment]
In the above-described embodiment, the surface layer 2B is made of the crystalline resin intermediate layer 2A and the crystalline resin that is larger than the MFR of the crystalline resin forming the intermediate layer 2A and has a short relaxation time on at least one surface of the intermediate layer 2A. Forming. Then, at least one of the intermediate layer 2A and the surface layer 2B, specifically, the intermediate layer 2A contains a metallocene ethylene-α-olefin copolymer manufactured using a metallocene catalyst.
For this reason, the stress applied to the intermediate layer 2A when it is extruded into a sheet is relieved by the surface layer 2B, and the residual stress that causes the formation of spherulites that are likely to be generated at a certain depth from the surface is reduced. . Furthermore, by including a metallocene ethylene-α-olefin copolymer at a depth where spherulites are generated, the formation and growth of spherulites are suppressed, the amount of spherulites is reduced and the size of spherulites is reduced. Becomes smaller. Therefore, light scattering by spherulites is reduced, and transparency can be improved (haze reduction).
Then, the respective crystalline resins of the intermediate layer 2A and the surface layer 2B are extruded in a molten state and cooled in a state of being laminated in a sheet shape to form an original fabric sheet 2, and the original fabric sheet 2 has a melting point higher than the crystallization temperature. Heat treatment is performed at the following temperature.
For this reason, there is no inconvenience that the higher-order structure in the raw sheet 2 having a good crystallinity obtained by cooling is destroyed and the transparency is impaired, and it can be formed into a good sheet shape. A transparent resin laminate 3 is obtained.

As the intermediate layer 2A, a propylene resin (a) having an isotactic pentad fraction of 85% to 99% and an MFR of 0.5 g / 10 min to 5.0 g / 10 min is 80% by mass to 99%. Metallocene ethylene-α produced using a metallocene catalyst and having a density of 898 kg / m ³ or more and 913 kg / m ³ or less, and MFR of 0.5 g / 10 min or more and 6.0 g / 10 min or less. -Olefin copolymer (b) It is formed from 0.5 mass% or more and 20 mass% or less.
For this reason, the refractive index of the propylene-based resin (a) in the intermediate layer 2A and the metallocene-based ethylene-α-olefin copolymer (b) that suppresses spherulite growth is approximately the same, and the transparency can be improved.
Furthermore, since the value of the viscosity ratio between the propylene resin (a) and the metallocene ethylene-α-olefin copolymer (b) is 1.0 or more and 3.0 or less, it can be uniformly dispersed and uniformly dispersed. It is possible to prevent a decrease in transparency due to inability to do so.
And the propylene-type resin (a) is mix | blended by 80 mass% or more and 99.5 mass% or less, and a metallocene-type ethylene-alpha-olefin copolymer (b) is 0.5 mass% or more and 20 mass% or less. For this reason, the inconvenience that rigidity falls by the metallocene-type ethylene-alpha-olefin copolymer (b) which becomes an impurity with respect to propylene-type resin (a) increases too much can be prevented. On the other hand, the metallocene ethylene-α-olefin copolymer (b) that suppresses spherulite growth is too small and is not sufficiently dispersed throughout the propylene resin (a), and spherulite growth cannot be sufficiently suppressed. The possibility that the transparency cannot be improved sufficiently can also be prevented.

Further, it is preferable to use a propylene-based resin as the crystalline resin for forming the intermediate layer 2A and the surface layer 2B.
For this reason, the transparent resin laminate 3 can be used in various fields by using a propylene-based resin that is widely used and can be easily formed into a sheet or heat-treated and does not affect the human body. Can be provided at low cost.

Then, linear low density polyethylene is used as the metallocene ethylene-α-olefin copolymer.
For this reason, the refractive index is substantially the same as that of the propylene-based resin (a), can be easily uniformly dispersed and mixed, and transparency can be easily improved. Therefore, the highly transparent transparent resin laminate 3 can be easily formed.

Moreover, the raw fabric sheet 2 is formed in a two-type three-layer structure in which the surface layer 2B is provided on both surfaces of the sheet-like intermediate layer 2A.
For this reason, compared with the case where it provides in one side, the stress applied at the time of extrusion of intermediate layer 2A can be eased more, residual stress can be reduced more, and transparency can be improved further.

And it is good also as a 5 layer structure which provided the intermediate | middle layer 2A on both surfaces of the base material layer formed from the crystalline resin used as a base material, and provided the surface layer 2B further on the surface of these intermediate | middle layers 2A.
Such a three-kind five-layer structure can inhibit the growth of spherulites that remain even if a low-viscosity propylene-based resin (a) is laminated on the surface layer, which causes a decrease in transparency due to light scattering. The generation of huge spherulites can be suppressed. Furthermore, by reducing the layer thickness to which the metallocene ethylene-α-olefin copolymer (b) is added, the refraction of light by the metallocene ethylene-α-olefin copolymer (b) which is a different substance is prevented. Therefore, transparency can be further improved.
In particular, by using a propylene-based resin as the crystalline resin of the base material layer, the base material layer, the intermediate layer 2A, and the surface layer 2B have substantially the same refractive index. A transparent resin laminate 3 can be obtained.

Moreover, in the manufacturing apparatus 1 of this embodiment, the raw fabric sheet 2 is manufactured with the cooling press apparatus 110, and it heat-processes with the heat processing apparatus 20 as it is, and the transparent resin laminated body 3 is manufactured in series.
For this reason, the desired highly transparent transparent resin laminate 3 can be efficiently produced.

[Modification]
In addition, the aspect demonstrated above shows the one aspect | mode of this invention, Comprising: This invention is not limited to above-described embodiment. Modifications and improvements within the scope of achieving the objects and effects of the present invention are included in the content of the present invention.
For example, after the raw fabric sheet 2 is manufactured, the transparent raw material sheet 2 may be wound up, supplied to the separate heat treatment apparatus 20 and heat-treated, and the transparent resin laminate 3 may be manufactured. The configuration is not limited to the above embodiment.
Moreover, although it was set as the structure which provided the surface layer 2B on both surfaces of the intermediate | middle layer 2A as the raw fabric sheet 2, it is good also as a 2 layer structure which provided the surface layer 2B only on the single side | surface of the intermediate | middle layer 2A. Moreover, it is good also as a 3 type | mold 3 layer structure which provided the intermediate | middle layer 2A in the single side | surface of a base material layer, and provided the surface layer 2B in the surface of this intermediate | middle layer 2A. Furthermore, you may make it the 3 type | mold 4 layer structure which provided the surface layer 2B only in the surface of one intermediate | middle layer 2A among the intermediate | middle layers 2A provided in both surfaces of the base material layer.
In addition, the MFR of the surface layer 2B is large relative to the crystalline resin intermediate layer 2A, such as the physical properties and blending amount of the propylene resin (a) and the metallocene ethylene-α-olefin copolymer (b), and the relaxation time is short. If it is conditions, it can set suitably according to the desired transparent resin laminated body 3. FIG. Furthermore, the propylene resin (a) and the metallocene ethylene-α-olefin copolymer (b) are not limited.

[Examples 1-8, Comparative Examples 1-5]
In the above embodiment, the specific conditions of the manufacturing apparatus and the manufacturing method are as follows. In addition, Table 1 shows raw material resins in each Example and each Comparative Example, and Tables 2 to 4 show layer configurations .

A container was manufactured from the raw sheet 2 using the heat treatment apparatus 20 of the manufacturing apparatus 1 using the raw material resin shown in Table 1. The manufacturing conditions are as follows.
◎ Extruder:
・ For first base material layer; diameter 90mm
・ For second base material layer; diameter 50mm
◎ Coat hanger die width dimension: 900mm
(Lamination of molten resin 2C by feed block method)
◎ Cooling roll surface roughness: Rmax = 0.1 μm
◎ Endless belt for cooling:
・ Material: Precipitation hardened stainless steel ・ Surface roughness: Rmax = 0.1 μm
・ Width dimension: 900mm
・ Length: 7700mm
・ Thickness dimension: 0.8mm
◎ Temperature of the endless belt 115 for cooling and the third cooling roll 113 into which the molten resin 2C is introduced into the cooling press device 110: 16 ° C.
◎ Take-up speed of raw sheet 2: 10 m / min ◎ Width dimension of original sheet 2: 780 mm
◎ Temperature during thermoforming of container: Surface temperature of raw sheet 2 130 ° C.

And the internal haze of the obtained raw fabric sheet 2 and the haze of the container were measured.
Here, the internal haze was measured using a haze measuring machine (NDH-300A, manufactured by Nippon Denshoku Industries Co., Ltd.). The internal haze was measured with a haze measuring machine after applying silicone oil on both sides of the sheet, sandwiching both sides of the sheet with a glass plate, eliminating the influence of the outside of the sheet. The haze of the container is determined by the ratio of the total light transmittance (Tt) representing the total amount of light transmitted through irradiation of the sheet to the diffused light transmittance (Td) diffused and transmitted by the sheet, as described in the above embodiment. (3).

Moreover, the average thickness of the container was measured using a micro gauge (ID-C112C, manufactured by Mitutoyo Corporation). The top surface of the container was cut out to 5 cm × 5 cm, and the average of a total of three points at the center and two ends was taken as one sample, and the average of the five samples was taken as the average thickness of the container.
The MFR and density of linear low density polyethylene (LLDPE) which is a metallocene ethylene-α-olefin copolymer are as described in the above embodiment.

The measurement results are shown in Tables 2-4.

[result]
From the results shown in Tables 2 to 4, a metallocene ethylene-α-olefin copolymer having a density of 898 kg / m ³ or more and 913 kg / m ³ or less and an MFR of 0.5 g / 10 min or more and 6.0 g / 10 min or less ( In the sheet in which b) was added to the intermediate layer, good transparency could be obtained. It turns out that the transparency improvement effect by the addition of the metallocene ethylene-α-olefin copolymer (b) is great.

  The present invention can be used for various uses that require transparency in addition to packaging uses such as foods, pharmaceuticals, and cosmetics.

DESCRIPTION OF SYMBOLS 1 ... Manufacturing apparatus 2 ... Raw fabric sheet | seat as a resin laminated body 2A ... Intermediate | middle layer 2B ... Surface layer 3 ... Transparent resin laminated body 10 ... Raw fabric sheet forming apparatus 20 ... Heat processing apparatus

Claims (9)

A method for producing a transparent resin laminate comprising: an intermediate layer formed of a crystalline resin; and a surface layer provided on at least one surface of the intermediate layer and formed of a crystalline resin,
The intermediate layer has a propylene-based resin (a) having an isotactic pentad fraction of 85% to 99% and an MFR of 0.5 g / 10 min to 5.0 g / 10 min. A metallocene ethylene-α-olefin having a density of 898 kg / m ³ or more and 913 kg / m ³ or less and an MFR of 0.5 g / 10 min or more and 6.0 g / 10 min or less. The copolymer (b) is formed from 0.5% by mass to 20% by mass,
The crystalline resin of the surface layer has a higher melt flow rate (hereinafter referred to as MFR) and shorter relaxation time than the crystalline resin forming the intermediate layer .
Each of the crystalline resin that forms the intermediate layer and the crystalline resin that forms the surface layer is melted and cooled in a state of being extruded and laminated in a sheet shape, thereby forming a resin laminate,
A method for producing a transparent resin laminate, comprising heat-treating the resin laminate at a temperature not lower than a crystallization temperature and not higher than a melting point. In the manufacturing method of the transparent resin laminated body of Claim 1 ,
Both the crystalline resins forming the intermediate layer and the surface layer are propylene-based resins. A method for producing a transparent resin laminate, wherein: In the manufacturing method of the transparent resin laminated body of Claim 2 ,
The metallocene ethylene-α-olefin copolymer is a linear low-density polyethylene. A method for producing a transparent resin laminate, wherein: In the manufacturing method of the transparent resin laminated body as described in any one of Claim 1- Claim 3 ,
Provide the intermediate layer on both sides of the base material layer formed of a crystalline resin,
A method for producing a transparent resin laminate, comprising providing the surface layer on a surface of the intermediate layer. In the manufacturing method of the transparent resin laminated body of Claim 4 ,
The method for producing a transparent resin laminate, wherein the crystalline resin forming the base material layer is a propylene-based resin. A molded body comprising an intermediate layer formed of a crystalline resin, and a surface layer formed on at least one surface of the intermediate layer and formed of a crystalline resin,
The intermediate layer has a propylene-based resin (a) having an isotactic pentad fraction of 85% to 99% and an MFR of 0.5 g / 10 min to 5.0 g / 10 min. A metallocene ethylene-α-olefin having a density of 898 kg / m ³ or more and 913 kg / m ³ or less and an MFR of 0.5 g / 10 min or more and 6.0 g / 10 min or less. The copolymer (b) is formed from 0.5% by mass to 20% by mass,
The crystalline resin of the surface layer has a higher melt flow rate (hereinafter referred to as MFR) and shorter relaxation time than the crystalline resin forming the intermediate layer .
The resin laminate obtained by laminating the crystalline resin forming the intermediate layer and the crystalline resin forming the surface layer into a sheet in a molten state and quenching is a temperature not lower than the crystallization temperature and not higher than the melting point. A molded product characterized by being thermoformed with. The molded body according to claim 6 ,
Provide the intermediate layer on both sides of the base material layer formed of a crystalline resin,
A molded body comprising the surface layer on both surfaces of the intermediate layer. A resin laminate in which a transparent resin laminate is formed by heat treatment,
An intermediate layer formed of a crystalline resin, and a surface layer provided on at least one surface of the intermediate layer and formed of a crystalline resin;
The crystalline resin of the intermediate layer is 80% by mass of propylene resin (a) having an isotactic pentad fraction of 85% to 99% and an MFR of 0.5 g / 10 min to 5.0 g / 10 min. The metallocene ethylene produced using a metallocene catalyst and having a density of 898 kg / m ³ or more and 913 kg / m ³ or less and an MFR of 0.5 g / 10 min or more and 6.0 g / 10 min or less. -Alpha-olefin copolymer (b) 0.5 mass% or more and 20 mass% or less,
The resin laminate, wherein the crystalline resin of the surface layer has a larger MFR and a shorter relaxation time than the crystalline resin forming the intermediate layer. In the resin laminate according to claim 8 ,
Provide the intermediate layer on both sides of the base material layer formed of a crystalline resin,
The resin layered product, wherein the surface layer is provided on both surfaces of the intermediate layer.

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