Multi-Layer Film, and Multi-Layer Structure In Which Same Is Used

Abstract

There is provided a multilayer film having a structure in which a layer (X) is an outermost layer and at least the layer (X), a layer (Y), and a layer (Z) are adjacently laminated in sequence, wherein the layer (X) is made of a resin composition (A) comprising a vinyl alcohol polymer (a) having a melting point of lower than 150° C. as a main component; the layer (Y) comprises an adhesive resin (B) having a melting point of lower than 150° C. as a main component; the layer (Z) comprises a polyolefin resin (C) having a melting point of lower than 150° C. as a main component; and the resin composition (A) comprises alkali metal ions (b) in 25 to 1500 ppm. Such a multilayer film is suitably used as a gas barrier film because it has excellent appearance and interlayer adhesiveness even while having a vinyl alcohol polymer as an outermost layer.

Claims

1. A multilayer film having a structure in which a layer (X) is an outermost layer and at least the layer (X), a layer (Y), and a layer (Z) are adjacently laminated in sequence, wherein the layer (X) is made of a resin composition (A) comprising a vinyl alcohol polymer (a) having a melting point of lower than 150° C. as a main component; the layer (Y) comprises an adhesive resin (B) having a melting point of lower than 150° C. as a main component; the layer (Z) comprises a polyolefin resin (C) having a melting point of lower than 150° C. as a main component; and the resin composition (A) comprises alkali metal ions (b) in 25 to 1500 ppm.

2. The multilayer film according to claim 1, wherein the vinyl alcohol polymer (a) is an ethylene-vinyl alcohol copolymer with an ethylene unit content of 15 to 85 mol %.

3. The multilayer film according to claim 1, wherein the vinyl alcohol polymer (a) has a modifying group comprising a primary hydroxy group represented by general formula (I): ##STR00006## wherein X represents a hydrogen atom, a methyl group or a group represented by R.sup.2—OH; and R.sup.2 represent independently of each other a single bond, an alkylene group having 1 to 9 carbon atoms or an alkyleneoxy group having 1 to 9 carbon atoms; the alkylene group and the alkyleneoxy group can contain a hydroxy group, an alkoxy group or a halogen atom.

4. The multilayer film according to claim 3, wherein in general formula (I), R.sup.1 is a single bond, and X is a hydroxymethyl group.

5. The multilayer film according to claim 3, wherein in general formula (I), R.sup.1 is a hydroxymethylene, and X is a hydrogen atom.

6. The multilayer film according to claim 3, wherein in general formula (I), R.sup.1 is a methylmethyleneoxy group, and X is a hydrogen atom.

7. The multilayer film according to claim 3, wherein in the vinyl alcohol polymer (a), a content of the modifying group containing a primary hydroxy group is 2 mol % or more and less than 20 mol %.

8. The multilayer film according to claim 1, wherein the resin composition (A) comprises a vinyl alcohol polymer (a′) having a melting point of 150° C. or higher in less than 50 mass %.

9. The multilayer film according to claim 1, wherein the resin composition (A) comprises at least one type of multivalent metal ions (c) selected from the group consisting of magnesium ions, calcium ions and zinc ions in 10 to 300 ppm.

10. The multilayer film according to claim 1, wherein the resin composition (A) comprises a higher aliphatic carboxylic acid (d) having 8 to 30 carbon atoms in 100 to 4000 ppm.

11. The multilayer film according to claim 1, wherein the polyolefin resin (C) comprises a polyethylene resin as a main component.

12. The multilayer film according to claim 1, wherein a thickness of the layer (X) is 0.2 μm or more and less than 20 μm, and a ratio of a thickness of the layer (X) to the total thickness of all layers of the multilayer film is less than 25%.

13. The multilayer film according to claim 1, wherein the multilayer film is stretched at least uniaxially by 3 times or more and less than 12 times.

14. The multilayer film according to claim 1, wherein the multilayer film is stretched biaxially 3 times or more and less than 12 times in a respective direction.

15. A vapor deposition multilayer film, comprising the multilayer film according to claim 1 having an inorganic vapor deposition layer (I) on an exposed surface side of the layer (X).

16. The multilayer film or the vapor deposition multilayer film according to claim 1, wherein an oxygen transmission rate (under the conditions of 20° C. and 65% RH) as determined in accordance with the method described in JIS K 7126-2 (equal-pressure method; 2006) is less than 60 cc/(m.sup.2.Math.day.Math.atm).

17. The multilayer film or the vapor deposition multilayer film according to claim 1, wherein a light transmittance at a wavelength of 600 nm is 80% or more.

18. A multilayer structure, which is a laminate of the multilayer film or the vapor deposition multilayer film according to claim 1, and at least one resin layer (R) comprising a thermoplastic resin (D) as a main component.

19. The multilayer structure according to claim 18, wherein the thermoplastic resin (D) comprises a polyolefin resin having a melting point of lower than 150° C. as a main component.

20. The multilayer structure according to claim 18, wherein both polyolefin resin (C) and thermoplastic resin (D) comprise a polyethylene resin as a main component.

21. The multilayer structure according to claim 18, wherein at least one of the layer (Z) and the resin layer (R) comprises a polyethylene resin as a main component, and a ratio of the total thickness of a layer or layers comprising a polyethylene resin as a main component to the total thickness of the multilayer structure is 0.75 or more.

22. The multilayer structure according to claim 18, wherein a layer comprising a resin having a melting point of 240° C. or higher as a main component and a metal layer with a thickness of 1 μm or more are absent.

23. A packaging material comprising the multilayer structure according to claim 18.

24. A recovered composition comprising a recovered material of the multilayer structure according to claim 18.

25. A method for recovering a multilayer structure comprising crushing the multilayer structure according to claim 18 and then melt-molding the crushed material.

Description

EXAMPLES

[0119] There will be specifically described the present invention with reference to Examples, but the present invention is not limited by these examples in any manner.

Production Example 1

(1) Synthesis of a Modified EVAc

[0120] In a 50 L high-pressure reaction tank equipped with a jacket, a stirrer, a nitrogen inlet, an ethylene inlet and an initiator addition port were charged 21 kg of vinyl acetate (hereinafter, referred to as “VAc”), 1.1 kg of methanol (hereinafter, referred to as “MeOH”) and 2.0 kg of 2-methylene-1,3-propanediol diacetate (modifying agent 1, hereinafter, referred to as “MPDAc”), and the mixture was heated to 60° C. followed by nitrogen bubbling for 30 min, to replace the atmosphere of the reaction tank with nitrogen. Then, ethylene was introduced such that a reaction tank pressure (ethylene pressure) became 3.8 MPa. After a temperature in the reaction tank was adjusted to 60° C., a solution of 16.8 g of 2,2′-azobis(2,4-dimethylvaleronitrile) (“V-65”, from Wako Pure Chemical Corporation) as an initiator in methanol was added to initiate polymerization. During the polymerization, an ethylene pressure and a polymerization temperature were maintained at 3.8 MPa and 60° C., respectively. 5 hours after polymerization initiation, a solution of additional 16.8 g of the initiator in methanol was added, and 10 hours after polymerization initiation, a polymerization rate of VAc reached 9% and then the mixture was cooled to terminate the polymerization. The reaction tank was opened to expel ethylene followed by nitrogen gas bubbling, to completely expel ethylene. Subsequently, unreacted VAc was removed under reduced pressure, and then MeOH was added to the modified ethylene-vinyl acetate copolymer (herein, sometimes referred to as “modified EVAc”) to which a structural unit derived from MPDAc by copolymerization, to prepare a 20% by mass MeOH solution.

(2) Synthesis of a Modified EVOH

[0121] In a 100 L reaction tank equipped with a jacket, a stirrer, a nitrogen inlet, a reflux condenser and a solution addition port, 4715 g of a 20% by mass solution of the modified EVAc in MeOH obtained by repeating the process in (1) was charged. While bubbling nitrogen into the solution, the solution was heated to 60° C., and a 2 N concentration solution of sodium hydroxide in MeOH at a rate of 4.7 mL/min over 2 hours. After addition of the solution of sodium hydroxide in MeOH, the mixture was stirred for 2 hours while a reaction system temperature was kept at 60° C., to let saponification reaction proceed. Then, 254 g of acetic acid was added for terminating the saponification reaction. Then, while the mixture was stirred under heating at 80° C., 3 L of ion-exchange water was added and MeOH was discharged out of the reaction tank, to precipitate a modified ethylene-vinyl alcohol copolymer (hereinafter, referred to as “modified EVOH”). The precipitated modified EVOH was collected by decantation and pulverized by a mixer. The modified EVOH powder thus obtained was then added to a 1 g/L aqueous solution of acetic acid (bath ratio 20:20 L of the aqueous solution/1 kg of the powder) and the mixture was washed with stirring for 2 hours. This was deliquored and further added to a 1 g/L aqueous solution of acetic acid (bath ratio: 20) and was washed with stirring for 2 hours. This was deliquored, the residue was added to ion-exchange water (bath ratio: 20) and washed with stirring for 2 hours followed by deliquoring. This process was repeated three times for purification. The product was immersed with stirring in 10 L of an aqueous solution containing 0.5 g/L of acetic acid and 0.1 g/L of sodium acetate for 4 hours and was deliquored. The product was dried at 60° C. for 16 hours, to give a crude dried modified EVOH.

(3) Production of Water-Containing Modified EVOH Pellets

[0122] In a 3 L stirring tank equipped with a jacket, a stirrer and a reflux condenser, 758 g of the crude dried modified EVOH obtained by repeating the process in (2), 398 g of water and 739 g of MeOH were charged, and the mixture was heated to 85° C. for dissolution. This solution was extruded through a glass tube with a diameter of 4 mm into a mixed solution of water/MeOH=90/10 cooled to 5° C. to precipitate a strand, which was then cut by a strand cutter into pellets, that is, water-containing pellets of the modified EVOH. A moisture content of the water-containing pellet of the modified EVOH obtained was determined to be 55% by mass as measured by a halogen moisture analyzer “HR73” from Mettler Toledo.

(4) Production of Modified EVOH Pellets and Resin Composition Pellets

[0123] To a 1 g/L aqueous solution of acetic acid (bath ratio: 20), 1577 g of the water-containing pellets of the modified EVOH obtained by repeating the process in (3) were added, and washed with stirring for 2 hours. This was deliquored, and then charged into a 1 g/L aqueous solution of acetic acid (bath ratio: 20), and the mixture was washed with stirring for 2 hours. After deliquoring, the same procedure was repeated with a fresh aqueous solution of acetic acid. The washed and deliquored product was added to ion-exchange water (bath ratio: 20) and washed with stirring for two hours followed by deliquoring. This procedure was repeated three times for purification, to give water-containing pellets of the modified EVOH free from the catalyst residue generated during the saponification reaction. The water-containing pellets were added to an aqueous solution of sodium acetate and acetic acid (bath ratio: 20), and immersed for 4 hours with periodic stirring. The pellets were deliquored, dried at 80° C. for 3 hours and then at 105° C. for 16 hours, to give modified EVOH pellets. Subsequently, the modified EVOH pellets and calcium stearate were mixed and then the mixture was fed to a twin-screw extruder “TEX30α” (screw diameter: 30 mm) manufactured by Japan Steel Works, Ltd. Using a screw having a forward staggered kneading disk with L (screw length)/D (screw diameter)=3, melt extrusion was conducted under the conditions of a melting temperature of 210 to 220° C. and an extrusion speed of 20 kg/hr, to give strands. The obtained strands were cooled and solidified in a cooling bath and then cut to provide resin composition A1 pellets. In this process, the amounts of the components were appropriately adjusted such that the contents in the resin composition were as described in Table 1.

(5) Content of Each Structural Unit in a Modified EVAc

[0124] Contents of ethylene units, vinyl acetate units and MPDAc units in the modified EVAc were calculated from 1H-NMR measurement of the modified EVAc before saponification. First, a small amount of the solution of the modified EVAc in MeOH obtained in (1) was sampled, and then the modified EVAc was precipitated in ion-exchange water. The precipitate was collected and dried at 60° C. under vacuum, to give a dried modified EVAc. Subsequently, the dry modified EVAc obtained was dissolved in dimethyl sulfoxide (DMSO)-d6 containing tetramethylsilane as an internal standard, and measured using a 500 MHz 1H-NMR (“GX-500” from JEOL Ltd.) at 80° C. The obtained spectrum was analyzed, and a content of ethylene units was 27.0 mol %, a content of vinyl ester units was 65.0 mol %, and a content of MPDAc units was 8.0 mol %.

(6) Saponification Degree of a Modified EVOH

[0125] Likewise, a modified EVOH after saponification was subjected to 1H-NMR spectrometry. The crude dried modified EVOH obtained in (2) was dissolved in dimethyl sulfoxide (DMSO)-d6 containing tetramethylsilane as an internal standard and tetrafluoroacetic acid (TFA) as an additive, and measured by a 500 MHz 1H-NMR (“GX-500” from JEOL Ltd.) at 80° C. The spectrum obtained was analyzed and a saponification degree of the modified EVOH was 99.9 mol % or more.

(7) Melting Point of a Modified EVOH

[0126] Using a differential scanning calorimeter (“Q2000” from TA Instrument), the modified EVOH pellets obtained in (4) were warmed from 20° C. to 220° C. at a rate of 10° C./min, cooled to 20° C. at a rate of 10° C./min, and again warmed from 20° C. to 220° C. at a rate of 10° C./min. A temperature at which a maximum value of an endothermic peak during the second warming was determined as a melting point. Resultantly, a melting point of the modified EVOH was 125° C.

(8) Contents of Alkali Metal Ions (b), Multivalent Metal Ions (c) and a Higher Aliphatic Carboxylic Acid (d) in a Resin Composition

[0127] In a Teflon® pressure vessel, 0.5 g of the resin composition pellets obtained in (4) was charged, and to the mixture was added 5 mL of concentrated nitric acid, to allow for decomposition at room temperature for 30 min. After decomposition, a lid was put on the vessel, and the mixture was heated by a wet decomposition apparatus (“MWS-2” from ACTAC Co., Ltd.) at 150° C. for 10 min and then at 180° C. for 5 min for further decomposition, and then cooled to room temperature. This process liquid was transferred to a 50 mL measuring flask and diluted with pure water to the predetermined volume. This solution was analyzed by an ICP emission spectrophotometer (“Optima 4300DV” from PerkinElmer Co., Ltd.), to determine contents of the alkali metal ions (b) and the multivalent metal ions (c). For contents of these components, a sodium ion content was 250 ppm, and a calcium ion content was 100 ppm. A content of a higher aliphatic carboxylic acid (d) was calculated from the amount of calcium stearate added in melt extrusion as described in (4), and was 1500 ppm.

(9) Yellow Index of Resin Composition Pellets

[0128] An yellow index (YI) of the resin composition pellets obtained in (4) was determined using a spectral colorimeter (“LabScan XE Sensor” from HunterLab), and the measurements were classified in accordance with the following criteria. Here, a YI value is an index representing yellowness of an object. The higher a YI value is, the stronger yellowness is and the less coloring is.

Classification: Criteria

[0129] A: less than 15 [0130] B: 15 or more and less than 25 [0131] C: 25 or more and less than 35 [0132] D: 35 or more and less than 45 [0133] E: 45 or more

(10) Thermal Decomposition Temperature of Resin Composition Pellets

[0134] The resin composition pellets obtained in (4) was warmed from 20° C. to 600° C. at a rate of 10° C./min under a nitrogen atmosphere using a thermogravimetry apparatus (“Q2000” from TA Instrument) and based on a temperature at which a mass was reduced to 95% of the original mass, classification was conducted in accordance with the following criteria.

Classification: Criteria

[0135] A: 360° C. or higher [0136] B: 350° C. or higher and lower than 360° C. [0137] C: 340° C. or higher and lower than 350° C. [0138] D: 330° C. or higher and lower than 340° C. [0139] E: lower than 330° C.

Production Examples 2 to 6 and C1, C2

[0140] Pellets of resin compositions A2 to A6, AC1, AC2 were produced as described in Production Example 1, except that the amount of sodium acetate added in (4) was changed such that the amount of alkali metal ions (b) in a resin composition obtained was as shown in Table 1.

Production Example 7

[0141] Pellets of resin composition A7 were produced as described in Production Example 1, except that sodium acetate added in (4) was replaced with potassium acetate and its amount was changed such that the amount of alkali metal ions (b) in a resin composition obtained was as shown in Table 1.

Production Examples 8 to 13

[0142] Pellets of resin compositions A8 to A13 were produced as described in Production Example 1, except that the amount of calcium stearate added in (4) was changed as shown in Table 1.

Production Example 14

[0143] Pellets of resin composition A14 were produced as described in Production Example 1, except that calcium stearate added in (4) was replaced with magnesium stearate, and its amount was changed as shown in Table 1.

Production Example 15

[0144] Pellets of resin composition A15 were produced as described in Production Example 1, except that calcium stearate added in (4) was replaced with zinc stearate, and its amount was changed as shown in Table 1.

Production Example 16

[0145] Pellets of resin composition A16 were produced as described in Production Example 1, except that calcium stearate added in (4) was replaced with an aqueous solution of calcium acetate using a liquid addition pump, and its amount was changed as shown in Table 1.

Production Example 17

[0146] Pellets of resin composition A17 were produced as described in Production Example 1, except that calcium stearate added in (4) was replaced with stearic acid, and its amount was changed as shown in Table 1.

Production Examples 18 to 21 and C3

[0147] Pellets of resin compositions A18 to A21, AC3 were produced as described in Production Example 1, except that the polymerization conditions in (1) were changed and a content of modifying group units containing a primary hydroxy group was changed as shown in Table 1.

Production Example 22

[0148] Pellets of resin composition A22 were produced as described in Production Example 1, except that in (1), MPDAc was replaced with 3,4-diacetoxy-1-butene (modifying agent 2); the polymerization conditions were changed; and contents of ethylene units and primary-hydroxy modifying group units were changed as shown in Table 1.

Production Example 23

[0149] 28 parts by weight of zinc acetylacetonate monohydrate and 957 parts by weight of 1,2-dimethoxyethane were mixed to give a mixed solution. To the mixed solution thus prepared, 15 parts by weight of trifluoromethanesulfonic acid was added with stirring, to give a catalyst solution. Then, to TEM-35BS extruder (37 mmφ, L/D=52.5) from Toshiba Machine Co., Ltd., an EVOH with an ethylene unit content of 44.0 mol % and a saponification degree of 99.9 mol % or more (although alkali metal ions, multivalent metal ions and a higher aliphatic carboxylic acid were absent) was charged, and the extruder was operated under the conditions of barrel C1: water cooled, barrels C2 to C3: 200° C., barrels C4 to C15: 240° C., and screw rotation speed: 250 rpm. From press-in port 1 in C8, epoxypropane (1.5 kg/hr) and the above catalyst solution were added. Then, from press-in port 2 in C13, an aqueous solution of sodium acetate was added. The discharged strands were cooled and solidified in a cooling bath and then cut to provide modified EVOH pellets. In this process, the amount of the catalyst solution was adjusted such that a melting point of the modified EVOH pellets thus obtained was 108° C. Pellets of resin composition A23 were produced as described in Production Example 1, except that the modified EVOH pellets were used.

Production Examples 24 and 25

[0150] Pellets of resin compositions A24, A25 were produced as described in Production Example 1, except that in (1), MPDAc was absent; the polymerization conditions were changed; and an ethylene unit content was changed as shown in Table 1.

Production Examples 26 and 27

[0151] Pellets of resin compositions A26, A27 were produced as described in Production Example 1, except that in (1), MPDAc was absent and the polymerization conditions were changed; in (2), the saponification reaction conditions were changed; and an ethylene unit content and a saponification degree were changed as shown in Table 1.

Production Examples C5 and C6

[0152] Pellets of resin compositions AC5, AC6 were produced as described in Production Example 1, except that in (1), MPDAc was absent; the polymerization conditions were changed; and an ethylene unit content was changed as shown in Table 1.

Production Examples 28 to 30 and C4

[0153] Resin composition A1 obtained in Production Example 1 and resin composition AC5 obtained in Production Example C5 were melt-mixed at a ratio shown in Table 1, to produce pellets of resin compositions A28 to A30, AC4. Specifically, pellets of resin compositions were mixed and then fed to a twin-screw extruder “TEX30α” (screw diameter: 30 mm) manufactured by Japan Steel Works, Ltd. Using a screw having a forward staggered kneading disk with L (screw length)/D (screw diameter)=3, melt extrusion was conducted under the conditions of a melting temperature of 210 to 220° C. and an extrusion speed of 20 kg/hr, to give strands. The obtained strands were cooled and solidified in a cooling bath and then cut to provide pellets of resin compositions A28 to A30, AC4.

TABLE-US-00001 TABLE 1 Resin composition (A) Vinyl alcohol polymer (a) Vinyl alcohol polymer (a′) Ethylene Modified Ethylene Melting unit Saponification group Melting unit point content degree Modifying content point content Type (° C.) (mol %) (mol %) agent .sup.1) X R.sup.1 (mol %) (° C.) (mol %) Production A1 125 27 ≥99.9 1 —CH.sub.2—OH Single bond 8 — — Example 1 Production A2 125 27 ≥99.9 1 —CH.sub.2—OH Single bond 8 — — Example 2 Production A3 125 27 ≥99.9 1 —CH.sub.2—OH Single bond 8 — — Example 3 Production A4 125 27 ≥99.9 1 —CH.sub.2—OH Single bond 8 — — Example 4 Production A5 125 27 ≥99.9 1 —CH.sub.2—OH Single bond 8 — — Example 5 Production A6 125 27 ≥99.9 1 —CH.sub.2—OH Single bond 8 — — Example 6 Production A7 125 27 ≥99.9 1 —CH.sub.2—OH Single bond 8 — — Example 7 Production A8 125 27 ≥99.9 1 —CH.sub.2—OH Single bond 8 — — Example 8 Production A9 125 27 ≥99.9 1 —CH.sub.2—OH Single bond 8 — — Example 9 Production A10 125 27 ≥99.9 1 —CH.sub.2—OH Single bond 8 — — Example 10 Production A11 125 27 ≥99.9 1 —CH.sub.2—OH Single bond 8 — — Example 11 Production A12 125 27 ≥99.9 1 —CH.sub.2—OH Single bond 8 — — Example 12 Production A13 125 27 ≥99.9 1 —CH.sub.2—OH Single bond 8 — — Example 13 Production A14 125 27 ≥99.9 1 —CH.sub.2—OH Single bond 8 — — Example 14 Production A15 125 27 ≥99.9 1 —CH.sub.2—OH Single bond 8 — — Example 15 Production A16 125 27 ≥99.9 1 —CH.sub.2—OH Single bond 8 — — Example 16 Production A17 125 27 ≥99.9 1 —CH.sub.2—OH Single bond 8 — — Example 17 Production A18 142 27 ≥99.9 1 —CH.sub.2—OH Single bond 6 — — Example 18 Production A19 133 27 ≥99.9 1 —CH.sub.2—OH Single bond 7 — — Example 19 Production A20 117 27 ≥99.9 1 —CH.sub.2—OH Single bond 9 — — Example 20 Production A21 123 44 ≥99.9 1 —CH.sub.2—OH Single bond 5 — — Example 21 Production A22 124 38 ≥99.9 2 H —CH(OH)— 6 — — Example 22 Production A23 108 44 ≥99.9 3 H —O—CH(CH.sub.3)— 5 — — Example 23 Production A24 124 69 ≥99.9 — — — — — — Example 24 Production A25 101 84 ≥99.9 — — — — — — Example 25 Production A26 125 27 80 — — — — — — Example 26 Production A27 125 44 84 — — — — — — Example 27 Production A28 125 27 ≥99.9 1 —CH.sub.2—OH Single bond 8 165 44 Example 28 Production A29 125 27 ≥99.9 1 —CH.sub.2—OH Single bond 8 165 44 Example 29 Production A30 125 27 ≥99.9 1 —CH.sub.2—OH Single bond 8 165 44 Example 30 Production AC1 125 27 ≥99.9 1 —CH.sub.2—OH Single bond 8 — — Example C1 Production AC2 125 27 ≥99.9 1 —CH.sub.2—OH Single bond 8 — — Example C2 Production AC3 — — — — — — — 158 27 Example C3 .sup.3) Production AC4 125 27 ≥99.9 1 —CH.sub.2—OH Single bond 8 165 44 Example C4 Production AC5 — — — — — — — 165 44 Example C5 Production AC6 — — — — — — — 191 27 Example C6 Resin composition (A) Higher Vinyl alcohol aliphatic polymer (a′) carboxylic Evaluation Saponification Mass Alkali metal ions (b) Multivalent metal ions (c) acid (d) .sup.4) Thermal degree ratio Content Content Content temperature (mol %) (a/a′) Type (ppm) Type (ppm) (ppm) YI decomposition Production — 100/0 Na 250 Ca 100 1500 B B Example 1 Production — 100/0 Na 60 Ca 100 1500 A A Example 2 Production — 100/0 Na 80 Ca 100 1500 A A Example 3 Production — 100/0 Na 400 Ca 100 1500 C B Example 4 Production — 100/0 Na 600 Ca 100 1500 C B Example 5 Production — 100/0 Na 900 Ca 100 1500 D C Example 6 Production — 100/0 K 425 Ca 100 1500 B B Example 7 Production — 100/0 Na 250 Ca 5 75 A A Example 8 Production — 100/0 Na 250 Ca 15 225 A A Example 9 Production — 100/0 Na 250 Ca 25 375 A A Example 10 Production — 100/0 Na 250 Ca 240 3599 C B Example 11 Production — 100/0 Na 250 Ca 280 4199 D C Example 12 Production — 100/0 Na 250 Ca 320 4799 D C Example 13 Production — 100/0 Na 250 Mg 60 1460 B C Example 14 Production — 100/0 Na 250 Zn 150 1450 B B Example 15 Production — 100/0 Na 250 Ca .sup.2) 100 — C C Example 16 Production — 100/0 Na 250 Ca 100 5000 B A Example 17 Production — 100/0 Na 250 Ca 100 1500 B B Example 18 Production — 100/0 Na 250 Ca 100 1500 B B Example 19 Production — 100/0 Na 250 Ca 100 1500 B B Example 20 Production — 100/0 Na 250 Ca 100 1500 A A Example 21 Production — 100/0 Na 250 Ca 100 1500 B B Example 22 Production — 100/0 Na 250 Ca + Zn 65 + 35 975 C B Example 23 Production — 100/0 Na 250 Ca 100 1500 A A Example 24 Production — 100/0 Na 250 Ca 100 1500 A A Example 25 Production — 100/0 Na 250 Ca 100 1500 B B Example 26 Production — 100/0 Na 250 Ca 100 1500 B B Example 27 Production ≥99.9  90/10 Na 250 Ca 100 1500 B B Example 28 Production ≥99.9  70/30 Na 250 Ca 100 1500 B B Example 29 Production ≥99.9  60/40 Na 250 Ca 100 1500 B B Example 30 Production — 100/0 Na 15 Ca 100 1500 A A Example C1 Production — 100/0 Na 1600 Ca 100 1500 E C Example C2 Production ≥99.9   0/100 Na 250 Ca 100 1500 B B Example C3 .sup.3) Production ≥99.9  40/60 Na 250 Ca 100 1500 B B Example C4 Production ≥99.9   0/100 Na 250 Ca 100 1500 B B Example C5 Production ≥99.9   0/100 Na 250 Ca 100 1500 D C Example C6 .sup.1) modifying agent 1: 2-methylene-1,3-propanediol diacetate, modifying agent 2: 3,4-diacetoxy-1-butene, modifying agent 3: epoxypropane .sup.2) Calcium acetate was used. .sup.3) As a polymer (a′), a modified vinyl alcohol polymer containing 4 mol % of a modifying group represented by Formula (I) (X: —CH.sub.2—OH, R.sup.1: single bond) obtained using modifying agent 1 was used. .sup.4) Type was stearic acid.

Example 1

(1) Production of an Unstretched Multilayer Film

[0154] Using the resin composition A1 pellets obtained in Production Example 1, a polyethylene resin (Japan Polypropylene Corporation, “Novatec™ LD LJ400”; low-density polyethylene, melting point 108° C.) and a polyethylene adhesive resin (Mitsui Chemicals, Inc., “Admer™ NF518”; maleic anhydride graft-modified linear low-density polyethylene adhesive resin, melting point: 120° C.), a 3-material 3-layer unstretched multilayer film (resin composition/polyethylene adhesive resin/polyethylene resin=18 μm/18 μm/144 μm) was deposited. A thickness of the coextruded film was adjusted by appropriately changing a screw rotation speed and a take-up roll speed.

[0155] An extruder and extrusion conditions, and a die used were as follows.

Resin Composition

[0156] Extruder: single-screw extruder (TOYO SEIKI Co., Ltd., Labo Machine Model ME CO-EXT)

[0157] Screw: diameter 20 mmφ, L/D20, full-flight screw

[0158] Extrusion temperature: supply zone/compression zone/measurement zone/die=175/200/220/220° C.

Polyethylene Adhesive Resin

[0159] Extruder: single-screw extruder (TECHNOVEL Corporation, SZW2OGT-20MG-STD)

[0160] Screw: diameter 20 mmφ, L/D20, full-flight screw

[0161] Extrusion temperature: supply zone/compression zone/measurement zone/die=175/200/220/220° C.

Polyethylene Resin

[0162] Extruder: single-screw extruder (Research Laboratory of Plastics Technology Co., Ltd. GT-32-A)

[0163] Screw: diameter 32 mmφ, L/D28, full-flight screw

[0164] Extrusion temperature: supply zone/compression zone/measurement zone/die=175/200/220/220° C.

[0165] Die: a coathanger die for a 3-material 3-layer film with a width of 300 mm (Research Laboratory of Plastics Technology Co., Ltd.)

[0166] Die temperature: 220° C.

(2) Production of a Biaxially Stretched Multilayer Film

[0167] The unstretched multilayer film obtained in (1) was stretched three times in a vertical direction and three times in a horizontal direction at 130° C. by a tenter type sequential biaxial stretching facility, to provide a 3-type 3-layer biaxially stretched multilayer film (resin composition/polyethylene adhesive resin/polyethylene resin=2 μm/2 μm/16 μm).

(3) Production of a Vapor-Deposited Biaxially Stretched Multilayer Film

[0168] On the surface of the resin composition layer of the biaxially stretched multilayer film obtained in (2) was vapor-deposited aluminum metal to a thickness of 50 nm by a known vacuum vapor deposition method to give a metal-vapor deposited biaxially stretched multilayer film (Al/resin composition/polyethylene adhesive resin/polyethylene resin=50 nm/2 μm/2 μm/16 μm).

(4) Production of a Multilayer Structure

[0169] On one side of an unstretched polyethylene film (Tohcello, Inc., “T.U.X. HZR-2”, melting point: 127° C., thickness: 50 μm) was applied a two-part adhesive (“Takelac™ A-520” and “Takenate™ A-50” from Mitsui Chemicals Inc.) and dried to a dry thickness of 2 μm, and laminated with the side of a vapor deposition surface of the vapor-deposited biaxially stretched multilayer film obtained in (3), to provide a multilayer structure (PE/adhesive/Al/resin composition/polyethylene adhesive resin/polyethylene resin=50 μm/2 μm/50 nm/2 μm/2 μm/16 μm).

(5) Evaluation of Appearance of a Multilayer Film

[0170] Appearance of the biaxially stretched multilayer film obtained in (2) was visually observed and classified in accordance with the following criteria. The results are shown in Table 2.

Classification: Criteria

[0171] A: uniform appearance with no unevenness [0172] B: moderate unevenness and/or streaks are observed [0173] C: unevenness and/or streaks are observed [0174] D: significant unevenness and/or streaks are observed [0175] E: prominent unevenness and/or streaks are observed, or cracks are observed

(6) Evaluation of Interlayer Adhesiveness

[0176] The multilayer structure obtained in (4) was humidity-conditions at 23° C. and 50% RH, and then cut into a sample with a length of 150 mm and a width of 15 mm along an extrusion direction. For the sample, peel strength was determined when it was peeled under an atmosphere of 23° C. and 50% RH in a T-type peeling mode at a tension rate of 250 mm/min by an autograph “DCS-50M type tensile testing machine” from Shimadzu Corporation, and evaluated in accordance with the following criteria. Here, a peeling interface is an Al/resin composition interface or a resin composition/polyethylene adhesive resin surface. The results are shown in Table 2.

Classification: Criteria

[0177] A: 250 g/15 mm or more [0178] B: 200 g/15 mm or more and less than 250 g/15 mm [0179] C: 150 g/15 mm or more and less than 200 g/15 mm [0180] D: 100 g/15 mm or more and less than 150 g/15 mm [0181] E: less than 100 g/15 mm

Examples 2 to 30 and Comparative Examples 1 to 6

[0182] Production and evaluation were conducted as described in Example 1, substituting resin compositions A2 to A30 and AC1 to AC6 for resin composition A1. The results are shown in Table 2.

TABLE-US-00002 TABLE 2 Evaluation Resin composition (A) Interlayer Type Appearance adhesiveness Example 1 A1 A B Example 2 A2 B C Example 3 A3 A C Example 4 A4 A A Example 5 A5 B A Example 6 A6 C A Example 7 A7 A A Example 8 A8 C C Example 9 A9 B C Example 10 A10 B B Example 11 A11 B B Example 12 A12 B C Example 13 A13 C C Example 14 A14 A B Example 15 A15 B B Example 16 A16 B A Example 17 A17 A C Example 18 A18 D C Example 19 A19 C B Example 20 A20 A B Example 21 A21 A C Example 22 A22 A B Example 23 A23 A B Example 24 A24 A D Example 25 A25 A D Example 26 A26 A C Example 27 A27 A C Example 28 A28 B B Example 29 A29 C B Example 30 A30 D C Comparative AC1 C E Example 1 Comparative AC2 E A Example 2 Comparative AC3 E E Example 3 Comparative AC4 E C Example 4 Comparative AC5 E E Example 5 Comparative AC6 E E Example 6

Example 31

(1) Production of a Multilayer Film

[0183] Using the resin composition Al pellets obtained in Production Example 1, polyethylene resin (Japan Polypropylene Corporation, “Novatec™ LD LJ400”; low-density polyethylene, melting point: 108° C.) and a polyethylene adhesive resin (Mitsui Chemicals, Inc., “Admer™ NF518”; linear low-density polyethylene adhesive resin, melting point: 120° C.), a process was conducted as described in Example 1, to deposit a 3-material 3-layer unstretched multilayer film (resin composition/polyethylene adhesive resin/polyethylene resin=2 μm/2 μm/16 μm).

(2) Light Transmittance of a Multilayer Film

[0184] For a multilayer film obtained in (1), a light transmittance at a wavelength of 600 nm was measured using an ultraviolet visible spectrophotometer “UV-2450” manufactured by Shimadzu Corporation, and then classified in accordance with the following criteria. Criteria A and B indicate that the multilayer structure can be suitably used for an application requiring transparency and visibility of the content. Criterion D indicates that the multilayer structure can be suitably used for an application requiring shading performance. The results are shown in Table 3.

Classification: Criteria

[0185] A: a light transmittance at 600 nm is 90% or more [0186] B: a light transmittance at 600 nm is 80% or more and less than 90% [0187] C: a light transmittance at 600 nm is 10% or more and less than 80% [0188] D: a light transmittance at 600 nm is less than 10%

(3) Oxygen Transmission Rate of a Multilayer Film

[0189] For the multilayer film obtained in (1), an oxygen transmission rate was measured where the resin composition layer was an oxygen supply side and the polyethylene resin layer was a carrier gas side in accordance with the method described in JIS K 7126-2 (equal-pressure method; 2006). Specifically, using an oxygen transmission measuring device (“MOCON OX-TRAN2/21” manufactured by Modern Controls Inc.), an oxygen transmission rate (unit: cc/(m.sup.2.Math.day.Math.atm)) was measured under the conditions: temperature: 20° C., humidity of the oxygen supply side: 65% RH, humidity of the carrier gas side: 65% RH, oxygen pressure: 1 atm and carrier gas pressure: 1 atm, and classified in accordance with the following criteria. A carrier gas was nitrogen gas containing 2% by volume of hydrogen gas. The results are shown in Table 3.

Classification: Criteria

[0190] A: less than 1 cc/(m.sup.2.Math.day.Math.atm) [0191] B: 1 cc/(m.sup.2.Math.day.Math.atm) or more and less than 5 cc/(m.sup.2.Math.day.Math.atm) [0192] C: 5 cc/(m.sup.2.Math.day.Math.atm) or more and less than 20 cc/(m.sup.2.Math.day.Math.atm) [0193] D: 20 cc/(m.sup.2.Math.day.Math.atm) or more and less than 40 cc/(m.sup.2.Math.day.Math.atm) [0194] E: 40 cc/(m.sup.2.Math.day.Math.atm) or more and less than 60 cc/(m.sup.2.Math.day.Math.atm) [0195] F: 60 cc/(m.sup.2.Math.day.Math.atm) or more and less than 100 cc/(m.sup.2.Math.day.Math.atm) [0196] G: 100 cc/(m.sup.2.Math.day.Math.atm) or more
(4) Oxygen Transmission Rate after Bending Processing of a Multilayer Film

[0197] The multilayer film obtained in (1) was humidity-conditioned under an atmosphere of 23° C. and 50% RH, and then was subjected to bending process using Gelvo Flex Tester (Rigaku Kogyo Co., Ltd.). Specifically, first the multilayer film was formed into a cylinder with a diameter of 3.5 inches, whose ends were gripped while it was twisted at the initial 3.5 inches of the stroke by an angle of 440° with an initial grip interval of 7 inches, and a grip interval at the maximum bending of 1 inch, and then at 2.5 inches was subjected to straight horizontal movement, and a reciprocating motion consisting of the movement were repeated 10 times at a speed of 40 times/min. For the multilayer film after bending process, an oxygen transmission rate was determined as described in (3), and classified in accordance with the same criteria.

Example 32

[0198] A 3-material 3-layer unstretched multilayer film (resin composition/polyethylene adhesive resin/polyethylene resin=10 μm/5 μm/5 μm) was deposited as described in Example 31, except that the extrusion conditions were changed, and evaluated as described in Example 31. The results are shown in Table 3.

Example 33

[0199] A 3-material 3-layer unstretched multilayer film (resin composition/polyethylene adhesive resin/polyethylene resin=8 μm/8 μm/64 μm) was deposited as described in Example 31, except that the extrusion conditions were changed. Next, it was stretched four times in a vertical direction at 130° C. by a tenter type sequential biaxial stretching facility, to produce a 3-material 3-layer uniaxially stretched multilayer film (resin composition/polyethylene adhesive resin/polyethylene resin=2 μm/2 μm/16 μm), and evaluated as described in Example 31. The results are shown in Table 3.

Example 34

[0200] A 3-material 3-layer unstretched multilayer film (resin composition/polyethylene adhesive resin/polyethylene resin=32 μm/32 μm/256 μm) was deposited as described in Example 31, except that the extrusion conditions were changed. Next, it was stretched, by a tenter type sequential biaxial stretching facility, four times in a vertical direction at 130° C. and then four times in a horizontal direction, to produce a 3-material 3-layer biaxially stretched multilayer film (resin composition/polyethylene adhesive resin/polyethylene resin=2 μm/2 μm/16 μm), and evaluated as described in Example 31. The results are shown in Table 3.

Example 35

[0201] By a known vacuum vapor deposition, aluminum metal was vapor-deposited to a thickness of 50 nm on the surface of the resin composition layer of the 3-material 3-layer biaxially stretched multilayer film produced in Example 34, to produce a metal vapor deposited biaxially stretched multilayer film (Al/resin composition/polyethylene adhesive resin/polyethylene resin=50 nm/2 μm/2 μm/16 μm), and evaluated as described in Example 31. The results are shown in Table 3.

Example 36

[0202] By a known vacuum vapor deposition, an alumina inorganic oxide was vapor-deposited to a thickness of 30 nm on the surface of the resin composition layer of the 3-material 3-layer biaxially stretched multilayer film produced in Example 34, to produce an inorganic oxide vapor deposited biaxially stretched multilayer film (Alx/resin composition/polyethylene adhesive resin/polyethylene resin=30 nm/2 μm/2 μm/16 μm), and evaluated as described in Example 31. The results are shown in Table 3. [0128]

Comparative Example 7

[0203] Film deposition and biaxial stretching were conducted as described in Example 34, substituting a polypropylene resin (Japan Polypropylene Corporation, “Novatec™ PP EA7AD”, melting point: 157° C.) for a polyethylene resin and (Mitsui Chemicals, Inc., “Admer™ QF500”, melting point: 162° C.) for a polyethylene adhesive resin, and during biaxial stretching, the film was broken.

Comparative Example 8

[0204] Film deposition and biaxial stretching were conducted as described in Example 34, except that a resin composition or a polyethylene adhesive resin was not used, to produce a biaxially stretched polyethylene film with a thickness of 20 μm, and evaluated as described in Example 31. The results are shown in Table 3.

Comparative Example 9

[0205] On one side surface of the biaxially stretched polyethylene film produced in Comparative Example 8, aluminum metal was vapor-deposited to a thickness of 50 nm by a known vacuum vapor deposition, to produce a metal vapor deposited biaxially stretched polyethylene film, and evaluated as described in Example 31. The results are shown in Table 3.

TABLE-US-00003 TABLE 3 Multilayer film/Vapor-deposited multilayer film Resin Adhesive Polyolefin composition resin resin Stretching ratio Thickness configuration (A) (B) (C) MD TD Layer (X) Layer (Y) Layer (Z) Type Type Type direction direction (μm) (μm) (μm) Example 31 A1 PE PE 1 1 2 2 16 Example 32 A1 PE PE 1 1 10 5 5 Example 33 A1 PE PE 4 1 2 2 16 Example 34 A1 PE PE 4 4 2 2 16 Example 35 A1 PE PE 4 4 2 2 16 Example 36 A1 PE PE 4 4 2 2 16 Comparative A1 PP PP 4 4 2 2 16 Example 7 Comparative — — PE 4 4 0 0 20 Example 8 Comparative — — PE 4 4 0 0 20 Example 9 Multilayer film/Vapor-deposited multilayer film Thickness configuration Evaluation Layer Inorganic vapor Gas barrier Total (X) deposition layer (I) property thickness ratio Thickness Light Before After (μm) (%) Type (nm) transmittance bending bending Example 31 20 10.0 — — B E E Example 32 20 50.0 — — B C C Example 33 20 10.0 — — B D D Example 34 20 10.0 — — A C C Example 35 20 10.0 Al 50 D A B Example 36 20 10.0 AlOx 30 A A B Comparative 20 10.0 — — Broken during stretching Example 7 Comparative 20 0.0 — — A G G Example 8 Comparative 20 0.0 Al 50 D E G Example 9

Example 37

[0206] The multilayer structure obtained in Example 1 (PE/adhesive/Al/resin composition/polyethylene adhesive resin/polyethylene resin=50 μm/2 μm/50 nm/2 μm/2 μm/16 μm) was crushed into pieces with a size of 5 mm.sup.2 or less. The crushed product and a polyethylene resin (Japan Polypropylene Corporation, “Novatec™ LD LJ400”; low-density polyethylene, melting point: 108° C.) were blended in a mass ratio (crashed product/polyethylene resin) of 40/60, with which single layer deposition was conducted under the conditions described below to provide a recovered composition film with a thickness of 50 μm. A thickness of the film was adjusted by appropriately changing a screw rotation speed and a take-up roll speed. Furthermore, using a polyethylene resin alone, a polyethylene film with a thickness of 50 μm was produced as a control as described above. [0207] Extruder: single-screw extruder from TOYO SEIKI Co., Ltd. [0208] Screw: diameter 20 mmφ (L/D=20, compaction ratio: 3.5, full-flight screw) [0209] Extrusion temperature: C1/C2/C3/D=230/230/230/230° C. [0210] Take-up roll temperature: 80° C. [0211] The recovered composition exhibited stable and excellent extrusion processability. Furthermore, the recovered composition film had the substantially same amount of gel and hard spots as the polyethylene film, and had uniform and good appearance except slight coloration.