JP4917299B2 - Stretched molded body and method for producing the same - Google Patents

Description

  The present invention relates to a stretched molded article such as a stretched film having transparency and excellent gas barrier properties such as oxygen and water vapor, particularly gas barrier properties under high humidity, and a method for producing the same.

In recent years, as a barrier material against oxygen or water vapor, inorganic oxides such as silicon oxide and aluminum oxide have been formed on film substrates by vacuum deposition, sputtering, ion plating, chemical vapor deposition, etc. A transparent gas barrier film is attracting attention. Such a transparent gas barrier film is a film obtained by depositing an inorganic oxide on a base material surface made of a biaxially stretched polyester film that is generally excellent in transparency and rigidity. When used as a packaging film, the inorganic oxide may be cracked by rubbing or stretching during post-processing printing or laminating or filling the contents, and the gas barrier property may be lowered.
On the other hand, a method of laminating a polyvinyl alcohol having a gas barrier property and an ethylene / vinyl alcohol copolymer on a biaxially stretched film substrate (for example, Patent Document 1), or a composition of polyvinyl alcohol and poly (meth) acrylic acid A method of coating a biaxially stretched film substrate (for example, Patent Document 2) has been proposed. However, the gas barrier film formed by laminating polyvinyl alcohol has a reduced oxygen barrier property under high humidity, and the composition of polyvinyl alcohol and poly (meth) acrylic acid has sufficiently advanced esterification, In order to improve the gas barrier property of the film, heating at a high temperature for a long time is required, which causes a problem in productivity, and the gas barrier property under high humidity is insufficient. Further, since the film is colored by reacting at high temperature for a long time and the appearance is impaired, improvement for food packaging is necessary.
On the other hand, since a composition of polyvinyl alcohol and poly (meth) acrylic acid requires a long reaction at a high temperature for esterification, a method of adding a crosslinking agent component such as an isocyanate compound to polyacrylic acid (for example, a patent) Document 3) and a method of reacting with a metal ion (for example, Patent Document 4) have been proposed. In this method, polyacrylic acid is crosslinked with a crosslinking agent component as described in Examples. As shown, it requires treatment at 180 to 200 ° C. for 5 minutes and at a high temperature.

JP-A-60-157830 (Claims) Japanese Patent No. 3203287 (Claim 1) JP 2001-310425 A (Claim 1, Example 1) JP 2003-171419 A (Claim 1, Table 1)

  Therefore, an object of the present invention is to obtain a stretched molded body such as a stretched film having transparency and excellent gas barrier properties such as oxygen and carbon dioxide, particularly gas barrier properties under high humidity.

In the present invention, at least one surface of the base material layer (X) stretched in at least one direction has an absorbance A ₀ based on νC═O of a carboxylic acid group near 1700 cm ⁻¹ in the infrared absorption spectrum and a carboxy near 1520 cm ^−1. Formation of a layer (Y) containing a polymer (a) of an unsaturated carboxylic acid compound polyvalent metal salt having a ratio (A ₀ / A) to an absorbance A based on νC═O of rate ions of less than 0.25 It is related with the extending | stretching molded object characterized by being made.

In the present invention, after applying a solution (s) containing an unsaturated carboxylic acid compound polyvalent metal salt having a polymerization degree of less than 20 on at least one surface of the base material layer (X) stretched in at least uniaxial direction, The present invention relates to a method for producing a stretched molded article, characterized by polymerizing an unsaturated carboxylic acid compound polyvalent metal salt to form a layer (Y) containing the polymer (a) of the unsaturated carboxylic acid compound polyvalent metal salt. .
In the present invention, at least one surface of the unstretched substrate layer (X) is coated with a solution (s) containing an unsaturated carboxylic acid compound polyvalent metal salt having a polymerization degree of less than 20, and simultaneously with the stretching treatment. And / or, after the stretching treatment, a layer (Y) containing a polymer (a) of an unsaturated carboxylic acid compound polyvalent metal salt is formed.

The stretched molded article such as a stretched film on which the layer (Y) containing the polymer (a) of the unsaturated carboxylic acid compound polyvalent metal salt of the present invention is formed has excellent gas barrier properties under high humidity.
The production method of the present invention can be easily applied to one or both sides of the base material layer by using an unsaturated carboxylic acid compound having a polymerization degree of less than 20, and has a high degree of neutralization. It is possible to easily produce a stretched molded article having a layer (Y) containing a polymer (a) of an unsaturated carboxylic acid polyvalent metal compound having excellent gas barrier properties.

Stretched molded body The stretched molded body of the present invention can be used without any particular limitation as a molded body of a film, sheet, tape, fiber or the like.
The stretched molded product such as the stretched film of the present invention has an absorbance A based on νC═O of a carboxylic acid group near 1700 cm ⁻¹ in the infrared absorption spectrum on at least one surface of the base material layer (X) stretched at least in a uniaxial direction. ₀ and 1520cm ratio between the absorbance a, based on the νC = O ^-1 vicinity of carboxylate ion _(a 0 / a) is less than 0.25 unsaturated carboxylic acid compound polyvalent polymer metal salt (a) The containing layer (Y) is formed. The layer (Y) containing the polymer (a) may be formed on one side of the stretched film or may be formed on both sides.
Stretched film Although the thickness of the stretched film of the present invention can be variously determined depending on the application, the thickness of the base layer is usually 5 to 500 μm, preferably 5 to 100 μm, more preferably 9 to 30 μm, and unsaturated. The thickness of the copolymer layer of the carboxylic acid compound polymetal salt is 0.01 to 100 μm, preferably 0.05 to 50 μm, more preferably 0.1 to 10 μm, and the total thickness of the gas barrier laminate is 20 to 20 μm. It exists in the range of 750 micrometers, More preferably, 25-430 micrometers.

Base material layer (X)
The base material layer (X) constituting the stretch-formed product of the present invention can be used without any particular limitation, such as a film, sheet, tape, fiber, etc. made of a thermoplastic resin.
As the thermoplastic resin, various known thermoplastic resins such as polyolefin (polyethylene, polypropylene, poly-4-methyl / 1-pentene, polybutene, etc.), polyester (polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, etc.), polyamide (Nylon-6, nylon-66, polymetaxylene adipamide, etc.), polyvinyl chloride, polyimide, ethylene / vinyl acetate copolymer or saponified product thereof, polyvinyl alcohol, polyacrylonitrile, polycarbonate, polystyrene, ionomer, or these And the like. Of these, polypropylene, polyester, polyamide and the like are preferable thermoplastic resins having good stretchability and transparency, and polyesters such as polyethylene terephthalate and polyethylene naphthalate are particularly preferable because of excellent barrier properties and heat resistance.
The base material layer (X) is a base material layer stretched at least in a uniaxial direction, and the stretched base material layer is excellent in heat resistance, rigidity, transparency, and gas barrier properties.
Moreover, in order to improve adhesiveness with the layer (Y) excellent in gas barrier property, these base material layers (X), for example, corona treatment, flame treatment, plasma treatment, undercoat treatment, primer A surface activation process such as a coating process or a frame process may be performed.
Layer (Y) containing polymer (a)
A layer (Y) containing a polymer (a) of an unsaturated carboxylic acid compound polyvalent metal salt is formed on one surface or both surfaces of the base material layer (X).

Polymer (a) of unsaturated carboxylic acid compound polyvalent metal salt
The polymer (a) of an unsaturated carboxylic acid compound polyvalent metal salt can be obtained by polymerizing an unsaturated carboxylic acid polyvalent metal salt.
The unsaturated carboxylic acid compound forming the unsaturated carboxylic acid compound polyvalent metal salt used in the unsaturated carboxylic acid compound polymer (a) is α, β-, such as acrylic acid, methacrylic acid, maleic acid, and itaconic acid. It is a carboxylic acid compound having an ethylenically unsaturated group, and has a polymerization degree of less than 20, preferably a monomer or a polymer having a polymerization degree of 10 or less. When a polymer (polymer compound) having a degree of polymerization exceeding 20 is used, a salt with a polyvalent metal compound described later may not be completely formed. As a result, it is obtained by polymerizing the metal salt. The layer may have poor gas barrier properties under high humidity. These unsaturated carboxylic acid compounds may be one kind or a mixture of two or more kinds.
Among these unsaturated carboxylic acid compounds, it is easy to form a salt in which the monomer is completely neutralized with a polyvalent metal compound, and a polymer layer obtained by polymerizing the salt is laminated on at least one side of the base material layer. The gas barrier laminate thus obtained is preferable because it is particularly excellent in gas barrier properties under high humidity.

Polyvalent metal compound The polyvalent metal compound which is a component forming the unsaturated carboxylic acid compound polyvalent metal salt according to the present invention is a metal or metal compound belonging to groups 2A to 7A, 1B to 3B and 8 of the periodic table. Specifically, magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc ( Zn), bivalent or higher metals such as aluminum (Al), oxides, hydroxides, halides, carbonates, phosphates, phosphites, hypophosphites, sulfates or sulfites of these metals Such as salt. Among these metal compounds, divalent metal compounds are preferable, and magnesium oxide, calcium oxide, barium oxide, zinc oxide, magnesium hydroxide, calcium hydroxide, barium hydroxide, zinc hydroxide, and the like are particularly preferable. When these divalent metal compounds are used, the gas barrier property under high humidity of the layer (Y) obtained by polymerizing a salt with the unsaturated carboxylic acid compound is particularly excellent. At least one kind of these polyvalent metal compounds is used, and only one kind may be used or two or more kinds may be used in combination. Among these polyvalent metal compounds, Mg, Ca, Zn, Ba and Al, and particularly Zn are preferable.

Unsaturated carboxylic acid compound polyvalent metal salt The unsaturated carboxylic acid compound polyvalent metal salt, which is a component constituting the polymer (a) of the unsaturated carboxylic acid compound polyvalent metal salt used in the present invention, has the above-mentioned degree of polymerization. It is a salt of an unsaturated carboxylic acid compound of less than 20 and the polyvalent metal compound. These unsaturated carboxylic acid compound polyvalent metal salts may be one kind or a mixture of two or more kinds. Among such unsaturated carboxylic acid compound polyvalent metal salts, the polymer layer from which zinc (meth) acrylate is obtained is particularly excellent in the hot water resistance, which is preferable.

  The layer (Y) containing the polymer (a) in the present invention is within the range not impairing the object of the present invention, and polyvinyl alcohol, ethylene / vinyl alcohol copolymer, polyvinyl pyrrolidone, polyvinyl ethyl ether, polyacrylamide, polyethyleneimine Water-soluble polymers such as starch, gum arabic and methylcellulose, acrylic acid ester polymers, ethylene / acrylic acid copolymers, polyvinyl acetate, ethylene / vinyl acetate copolymers, polyesters, polyurethanes and other high molecular weight compounds Various additives such as lubricants, slip agents, anti-blocking agents, antistatic agents, antifogging agents, pigments, dyes, inorganic or organic fillers may be included, and wetting with the substrate described below Various surfactants and the like may be included in order to improve the properties and adhesion. The proportions of these other components can be varied as required.

Among these, since the vinyl alcohol polymer (b) is easy to coat the base material layer (X) and has excellent gas barrier properties, it is desirable to use it together.
That is, the layer (Y) containing the polymer (a) of the present invention is preferably composed of a polymer (a) of an unsaturated carboxylic acid compound polyvalent metal salt and a vinyl alcohol polymer (b).
Vinyl alcohol polymer (b)
Examples of the vinyl alcohol polymer include polyvinyl alcohol, an ethylene-vinyl alcohol copolymer, and a modified vinyl alcohol polymer. Polyvinyl alcohol has no particular problem as long as it can be mixed, but preferably has a degree of polymerization of 100 to 3000, more preferably 200 to 2500, and most preferably 300 to 2000. Within this range, the base layer is easily coated with an aqueous solution and has good stretchability and gas barrier properties. Further, the saponification degree is 90% or more, preferably 95% or more. If it is within this range, the gas barrier property is good. Moreover, you may use olefin containing polyvinyl alcohol from water resistance or extending | stretching property. The olefin content is 0 to 25 mol%, preferably 1 to 20 mol%, more preferably 2 to 16 mol%, and the olefin is preferably those having 4 or less carbon atoms, such as ethylene, propylene, n-butene, isobutene and the like. Among them, ethylene is most preferable from the viewpoint of water resistance.
A suitable example of the vinyl alcohol polymer is a modified vinyl alcohol polymer.
The modified vinyl alcohol polymer is modified by adding a reactive group to the vinyl alcohol polymer by adding, replacing, or esterifying various known reactive groups (reactive groups). And a saponified copolymer obtained by copolymerizing a vinyl ester such as vinyl acetate and an unsaturated compound having a reactive group. Examples of these reactive polymerizable groups include (meth) acrylate groups, (meth) acryloyl groups, (meth) acrylamide groups, vinyl groups, allyl groups, styryl groups, thiol groups, silyl groups, acetoacetyl groups, and epoxy groups. It is done. The amount of the reactive group can be appropriately determined, but since the gas barrier property inherent to the vinyl alcohol polymer may be impaired when the amount of the OH group of the vinyl alcohol polymer serving as the substrate is decreased, usually, The amount of reactive groups is in the range of 0.001 to 50 mol% (the total of reactive groups and OH groups is 100 mol%). These modified vinyl alcohol polymers are preferably soluble in water, lower alcohols, and organic solvents, and those that are particularly soluble in water-lower alcohol mixed solvents are preferred.

In the aqueous solution of the vinyl alcohol polymer, a solvent other than water, for example, alcohols such as methanol, ethanol and isopropanol, ketones such as acetone and methyl ethyl ketone, or other diethyl ether, tetrahydrofuran and the like, if necessary, It is also possible to add two or more types in combination. In addition, a wettability improver, an antistatic agent, and other various additives can be added to the polyvinyl alcohol polymer as long as the characteristics of the present invention are not impaired.
When these vinyl alcohol polymers (b) are used in combination, the layer (Y) containing the polymer (a) of the present invention generally has a polymer (a) of an unsaturated carboxylic acid compound polyvalent metal salt of 1 (1). It is usually composed of ˜99% by weight and the vinyl alcohol polymer (b) from 1 to 99% by weight.
The layer (Y) containing the polymer (a) usually has an absorbance A ₀ based on νC═O of carboxylic acid groups near 1700 cm ⁻¹ in the infrared absorption spectrum and νC═O of carboxylate ions near 1520 cm ^−1. A polymer (a) of a polyvalent metal salt of an unsaturated carboxylic acid compound having a ratio (A ₀ / A) with an absorbance A based on the formula (A ₀ / A) of less than 0.25, preferably less than 0.20.
The layer (Y) containing a polymer (a) of a polyvalent metal salt of an unsaturated carboxylic acid compound has excellent gas barrier properties, and is free from carboxylate ions formed by ionic crosslinking of a carboxylic acid group and a polyvalent metal. In the infrared spectrum, the absorption based on νC═O of the free carboxylic acid group is around 1700 cm ⁻¹ , and the absorption based on νC═O of the carboxylate ion is around 1520 cm ⁻¹ , respectively. is there.
Therefore, the fact that the (A ₀ / A) of the layer (Y) containing the polymer (a) is less than 0.25 indicates that there are no or few free carboxylic acid groups. A layer composed of a film exceeding .25 has a large content of free carboxylic acid groups, and there is a possibility that the gas barrier resistance under high humidity may not be improved.
Ratio of absorbance A ₀ based on νC═O of a carboxylic acid group near 1700 cm ⁻¹ in the present invention to absorbance A based on νC═O of a carboxylate ion near 1520 cm ⁻¹ in an infrared absorption spectrum (A ₀ / A) Cut out a sample for measurement of 1 cm × 3 cm from a stretched film (a laminate having excellent gas barrier properties), and its surface (layer (Y) containing an unsaturated carboxylic acid compound polyvalent metal salt polymer (a)). An infrared absorption spectrum was obtained by infrared total reflection measurement (ATR method), and absorbance A ₀ and absorbance A were first determined by the following procedure.

1700cm absorbance based νC = O ^-1 vicinity of the carboxylic acid groups _{A 0:} a absorbance of the infrared absorption spectrum of 1660 cm ^-1 and 1760 cm ^-1 connected by a straight line (N), 1660~1760cm maximum absorbance between ^-1 ( The straight line (O) was dropped vertically from around 1700 cm ^−1, and the absorbance distance (length) between the intersection of the straight line (O) and the straight line (N) and the maximum absorbance was defined as absorbance A ₀ .
1520 cm ^-1 vicinity of carboxylate ion of νC = O based upon the absorbance A: connected by a straight line (L) and the absorbance of the infrared absorption spectrum of 1480 cm ^-1 and 1630 cm ^-1, the maximum absorbance between 1480~1630cm ^{-1 (1520cm The} straight line (M) was dropped vertically from the vicinity of ⁻¹ ), and the absorbance distance (length) between the intersection of the straight line (M) and the straight line (L) and the maximum absorbance was defined as absorbance A. The peak position of maximum absorbance (near 1520 cm ⁻¹ ) may vary depending on the metal species of the counter ion. For example, calcium is near 1520 cm ⁻¹ , zinc is near 1520 cm ⁻¹ , magnesium is near 1540 cm ⁻¹ , and In sodium (Na), it is around 1540 cm ⁻¹ .
Next, the ratio (A ₀ / A) was determined from the absorbance A ₀ and the absorbance A determined by the above method.
In addition, the measurement of the infrared spectrum in the present invention (infrared total reflection measurement: ATR method)
Using a FT-IR350 apparatus manufactured by JASCO Corporation, a KRS-5 (Thallium Bromide-Iodide) crystal was mounted, and the measurement was performed under the conditions of an incident angle of 45 degrees, room temperature, resolution of 4 cm ⁻¹ , and number of integrations of 150 times.

Manufacturing method of stretched film (1)
As a method for producing the stretched film of the present invention, after applying a solution (s) containing an unsaturated carboxylic acid compound polyvalent metal salt having a degree of polymerization of less than 20 on at least one side of the stretched substrate layer There is a method of polymerizing an unsaturated carboxylic acid compound polyvalent metal salt to form a layer (Y) containing a polymer (a) of an unsaturated carboxylic acid compound polyvalent metal salt.
As a method for preparing a solution (s) containing an unsaturated carboxylic acid compound polyvalent metal salt having a degree of polymerization of less than 20, the unsaturated carboxylic acid compound and the polyvalent metal compound are reacted in advance and unsaturated. The polyvalent metal salt of the carboxylic acid compound may be used as a solution, or the unsaturated carboxylic acid compound and the polyvalent metal compound may be directly dissolved in a solvent to form a polyvalent metal salt solution.
As a method for producing a stretched film of the present invention, when the unsaturated carboxylic acid compound and the polyvalent metal compound are directly dissolved in a solvent, that is, a solution containing the unsaturated carboxylic acid compound and the polyvalent metal compound is used. In this case, it is preferable to add the polyvalent metal compound in an amount exceeding 0.3 chemical equivalent ratio with respect to the unsaturated carboxylic acid compound. When a mixed solution having a polyvalent metal compound addition amount of 0.3 chemical equivalent ratio or less is used, a polymer layer having a large content of free carboxylic acid groups is obtained, and as a result, a stretched film having a low gas barrier property is obtained. There is a fear. In addition, the upper limit of the amount of polyvalent metal compound added is not particularly limited, but when the amount of polyvalent metal compound added exceeds 1 chemical equivalent ratio, unreacted polyvalent metal compound increases. The ratio is preferably less than the ratio, preferably less than the 2 chemical equivalent ratio.
In addition, the chemical equivalent ratio in this invention shows the chemical equivalent ratio of the polyvalent metal compound with respect to an unsaturated carboxylic acid compound, and is a value calculated by the following formula | equation.
Chemical equivalent ratio = (number of moles of polyvalent metal compound) × (valence of polyvalent metal compound) / number of moles of carboxyl group contained in unsaturated carboxylic acid compound For example, calcium hydroxide (molecular weight 74 g) as the polyvalent metal compound The chemical equivalent ratio is 1 when 37 g of acrylic acid monomer (molecular weight 72 g / mol) is mixed as an unsaturated carboxylic acid compound.
In addition, when a mixed solution of an unsaturated carboxylic acid compound and a polyvalent metal compound is used, the unsaturated carboxylic acid compound is usually added while the unsaturated carboxylic acid compound and the polyvalent metal compound are dissolved in a solvent. Although a valent metal salt is formed, it is preferable to mix for 1 minute or more in order to ensure the formation of the polyvalent metal salt.
Examples of the solvent used for the solution of the unsaturated carboxylic acid compound polyvalent metal salt include water, lower alcohols such as methyl alcohol, ethyl alcohol, and isopropyl alcohol, organic solvents such as acetone and methyl ethyl ketone, and mixed solvents thereof. Most preferred.

As a method of applying the solution (s) containing the polyvalent metal salt of an unsaturated carboxylic acid compound to the base material layer (X), a method of applying the solution to the surface of the base material layer, a base material layer on the solution Various known coating methods such as a method of immersing the solution and a method of spraying the solution on the surface of the base material layer can be employed.
Examples of the method for applying the solution (s) containing the polyvalent metal salt of the unsaturated carboxylic acid compound to the base material layer (X) include an air knife coater, a direct gravure coater, a gravure offset, an arc gravure coater, and a gravure reverse. And various other known types such as a gravure coater such as a jet nozzle method, a reverse roll coater such as a top feed reverse coater, a bottom feed reverse coater and a nozzle feed reverse coater, a 5-roll coater, a lip coater, a bar coater, a bar reverse coater, and a die coater. Using a coating machine, the amount in the solution (s) of the unsaturated carboxylic acid compound polyvalent metal salt (solid content) is 0.05 to 100 g / m ² , preferably 0.1 to 50 g / m ^2. It may be applied as follows. As a method of applying the solution (s) of the unsaturated carboxylic acid compound polyvalent metal salt to the surface of the base material layer (X), various known methods, for example, a method of applying with a brush or the like, the solution (s) For example, a method of immersing the base material layer (X), a method of spraying the solution (s) on the surface of the base material layer (X) and the like can be employed.

  When the unsaturated carboxylic acid compound polyvalent metal salt is dissolved, other unsaturated carboxylic acids (di) such as methyl (meth) acrylate and ethyl (meth) acrylate, as long as the object of the present invention is not impaired. Monomers such as ester compounds, vinyl ester compounds such as vinyl acetate, or low molecular weight compounds, lubricants, slip agents, anti-blocking agents, antistatic agents, antifogging agents, pigments, dyes, inorganic or organic fillers, etc. In order to improve the wettability with the base material layer, various surfactants and the like may be added.

In order to polymerize the solution (coating layer) of the unsaturated carboxylic acid compound polyvalent metal salt formed (coated) on at least one surface of the base material layer (X), various known methods, specifically, for example, Examples thereof include irradiation with ionizing radiation and heating.
When ionizing radiation is used, it is not particularly limited as long as the wavelength region is an energy ray in the range of 0.0001 to 800 nm. Examples of such energy rays include α rays, β rays, γ rays, X rays, and visible rays. , Ultraviolet rays, electron beams and the like. Among these ionizing radiations, visible light in the wavelength range of 400 to 800 nm, ultraviolet light in the range of 50 to 400 nm, and electron beam in the range of 0.01 to 0.002 nm are easy to handle and the devices are widespread. Therefore, it is preferable.
When visible light and ultraviolet light are used as the ionizing radiation, it is necessary to add a photopolymerization initiator to the solution of the unsaturated carboxylic acid compound polyvalent metal salt. As the photopolymerization initiator, known ones can be used. For example, 2-hydroxy-2methyl-1-phenyl-propan-1-one (trade name; Darocur 1173, manufactured by Ciba Specialty Chemicals), 1-Hydroxy-cyclohexyl ruphenyl ketone (Ciba Specialty Chemicals product name; Irgacure 184), Bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide (Ciba Specialty Chemicals product name) Irgacure 819), 1- [4- (2-hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl-1-propan-1-one (trade name; Irgacure 2959, manufactured by Ciba Specialty Chemicals) ), Α-hydroxyketone, acylphosphine oxy A mixture of id, 4-methylbenzophenone and 2,4,6-trimethylbenzophenone (Lamberty Chemical Specialty, trade name; Essaure KT046), Esacure KT55 (Lamberti Chemical Specialty), 2,4,6- A radical polymerization initiator manufactured and sold under the trade name of trimethylbenzoyldiphenylphosphine oxide (trade name; Speed Cure TPO manufactured by Ramson Fire Chemical Co., Ltd.) can be mentioned. Furthermore, a polymerization accelerator can be added to improve the polymerization degree or polymerization rate, and examples thereof include N, N-dimethylamino-ethyl- (meth) acrylate and N- (meth) acryloyl-morpholine. .

  When the unsaturated carboxylic acid compound polyvalent metal salt is polymerized, the solution (s) may be polymerized in a state containing a solvent such as water, or may be polymerized after being partially dried. When (s) is polymerized immediately after coating, the resulting polymer layer may be whitened because of the large evaporation of the solvent when the metal salt is polymerized. On the other hand, the solvent (moisture) decreases, and the unsaturated carboxylic acid compound polyvalent metal salt may precipitate as crystals. When polymerization is performed in such a state, formation of the resulting polymer layer becomes insufficient, resulting in heavy polymerization. There is a possibility that the gas barrier property may not be stable due to whitening of the combined layer. Therefore, when the coated unsaturated carboxylic acid compound polyvalent metal salt is polymerized, it is preferably polymerized in a state containing appropriate moisture.

Manufacturing method of stretched film (2)
As another production method of the stretched film of the present invention, a solution (s) containing an unsaturated carboxylic acid compound polyvalent metal salt having a degree of polymerization of less than 20 is applied to at least one surface of the unstretched substrate layer (X). And a layer (Y) containing a polymer (a) of an unsaturated carboxylic acid compound polyvalent metal salt is formed at the same time and / or after the stretching treatment. There is.
As one specific example of such a production method, a solution (s) containing an unsaturated carboxylic acid compound polyvalent metal salt having a degree of polymerization of less than 20 on at least one surface of the unstretched base material layer (X). Coating, prepolymerizing an unsaturated carboxylic acid compound polyvalent metal salt to form a layer (Y) containing a prepolymer (a ′), and then a layer containing the prepolymer (a ′) (Y) and the unstretched base material layer (X) are stretched together, and at the time of stretching, or thereafter, the prepolymerized product (a ′) is further polymerized, and the unsaturated carboxylic acid compound polyvalent metal salt There is a method (2-1) for producing a stretched film by forming a layer (Y) containing a polymer (a).

Manufacturing method of stretched film (2-1)
In this production method (2-1), a solution (s) containing an unsaturated carboxylic acid compound polyvalent metal salt having a degree of polymerization of less than 20 was applied to at least one surface of the unstretched base material layer (X). Then, the unsaturated carboxylic acid compound polyvalent metal salt is prepolymerized to form a layer (Y) containing the prepolymer (a ′).
At this stage, the layer (Y) is starting to retain the film form in the state of the prepolymer (a ′). At this stage, the layer (Y) containing the prepolymer (a ′) and the unstretched base material layer (X) are both stretched.
Thereby, a stretched film is formed.

In the prepolymerization prepolymerization, when the polymerization rate becomes too high, when the prepolymer (a ′) and the unstretched base material layer (X) are stretched, the polymer layer of the unsaturated carboxylic acid compound polyvalent metal salt is formed. Since cracks may occur, the polymerization rate of pre-polymerization (how to obtain the polymerization rate is shown below) is usually in the range of 1 to 70%, preferably 3 to 60%, more preferably 5 to 50%. It is preferable.
When prepolymerizing the solution (s) of the polyvalent metal salt of the unsaturated carboxylic acid compound, it is necessary to prepolymerize the unsaturated carboxylic acid compound polyvalent metal salt in the presence of a solvent. The concentration of the unsaturated carboxylic acid compound polyvalent metal salt solution at the time of prepolymerization is not particularly limited as long as the unsaturated carboxylic acid compound polyvalent metal salt crystals do not precipitate, but is usually 70% by weight or less, particularly The range of 60 to 20% by weight, in other words, the content of the solvent (water) is preferably 30% by weight or more, particularly 40 to 80% by weight.
The temperature at which the unsaturated carboxylic acid compound polyvalent metal salt is prepolymerized in the presence of a solvent is not particularly limited as long as it is not the temperature at which the solvent boils, but is usually 60 ° C. or less, particularly from room temperature to 50 ° C. It is preferable to carry out within a range. If the temperature at the prepolymerization is too high, the solvent evaporates faster and crystals of the unsaturated carboxylic acid compound polyvalent metal salt are likely to precipitate, whereas if the temperature is too low, the solvent is removed after the main polymerization. It is necessary to lengthen the drying time and lengthen the production line of the layer (Y) excellent in gas barrier properties.
In the prepolymerization of the unsaturated carboxylic acid compound polyvalent metal salt solution, if the polymerization rate is kept at 70% or less, the water content in the unsaturated carboxylic acid compound polyvalent metal salt solution is as low as 30% by weight or less. However, the appearance and gas barrier properties of the layer (Y) obtained by the main polymerization are excellent.

When the unsaturated carboxylic acid compound polyvalent metal salt solution (s) is preliminarily polymerized by irradiation with ionizing radiation, the irradiation dose of ionizing radiation is usually 1 to 50 mJ / cm ² , particularly 3 to 15 mJ / cm. A range of ² is preferable. When the irradiation amount exceeds 50 mJ, the polymerization rate at the time of preliminary polymerization increases, and the appearance of the layer (Y) excellent in gas barrier properties obtained by the main polymerization, particularly transparency, may be deteriorated.

After the stretching treatment and main polymerization prepolymerization, the prepolymer (a ′) and the unstretched base material layer (X) are stretched together.
Stretching is usually about 1.2 to 50 times in a uniaxial or biaxial direction. The stretching temperature can be appropriately adjusted according to the type of the base material layer. The stretching treatment is usually about 1.2 to 10 times, particularly preferably 1.2 to 5 times, at least in the uniaxial direction. The stretching temperature can be appropriately adjusted depending on the material of the base material layer (X), but is usually 50 ° C to 250 ° C.
In this production method, the prepolymer (a ′) may be main-polymerized after the stretching treatment, or the prepolymer (a ′) may be main-polymerized in parallel with the stretching treatment.
The prepolymer (a ′) forms a polymer (a) of an unsaturated carboxylic acid compound polyvalent metal salt by main polymerization.
The main polymerization is preferably performed after partially drying the coating solution in the prepolymer (a ′). In addition, the drying of the coating liquid does not completely remove the solvent, but a suitable solvent (water if an aqueous solution is used) in the coating liquid, preferably in a state containing the solvent in the range of 3 to 60% by weight. The main polymerization is preferable. When there is no solvent contained in the coating liquid, there is a risk that the oxygen barrier property of the layer (Y) obtained by the main polymerization may be reduced, and when too much solvent is contained in the coating liquid, the main polymerization is performed. There is a possibility that the appearance of the layer (Y) to be obtained, particularly the transparency, may be lowered.
When performing the polymerization by irradiation with ionizing radiation, usually, 50~1000mJ / cm ² irradiation amount of ionizing radiation, particularly it is preferably in the range of 100 to 500 mJ / cm ^2. By setting the irradiation amount in such a range, a layer (Y) excellent in gas barrier properties having a polymerization rate of 80% or more, preferably 90%, can be stably obtained.

Manufacturing method of stretched film (2-2)
As another production method of the stretched film of the present invention, a solution (s) containing an unsaturated carboxylic acid compound polyvalent metal salt having a degree of polymerization of less than 20 is applied to at least one surface of the unstretched substrate layer (X). After the unstretched base material layer (X) and the layer (Y) containing the polymer (a) are stretched together, the unsaturated carboxylic acid compound polyvalent metal salt is polymerized, thereby The layer (Y) containing a polymer (a) of a saturated carboxylic acid compound polyvalent metal salt is formed, and there is a method for producing a stretched molded product according to claim 7.

  This manufacturing method is different from the manufacturing method (2-1) in that polymerization is performed after the stretching treatment without performing preliminary polymerization. In addition, a draw ratio and a drawing temperature are the same as in the case of the production method (2-1).

Layer (Z) made of adhesive resin (c)
Between the base material layer (X) and the layer (Y) containing the polymer (a), it is desirable to provide a layer (Z) made of an adhesive resin (c) in order to enhance the adhesiveness.
Examples of the layer (Z) made of the adhesive resin (c) include a layer under-coated with an epoxy-based, urethane-based, acrylic-based primer or the like. Moreover, there exists a layer (Z) which consists of adhesive resin (c) as another layer (Z) which improves the adhesiveness used suitably.

Adhesive resin (c)
As the adhesive resin (c), various known adhesive resins can be used, and modified polyolefins and ionomer resins are particularly preferable.
Modified polyolefin The modified polyolefin used in the present invention is one in which a part or all of the polyolefin is graft-modified with an unsaturated carboxylic acid or a derivative thereof (graft monomer).
Examples of the polyolefin include polyethylene, ethylene-α-olefin copolymer, and polypropylene. Among them, the propylene-based polymer includes propylene homopolymer or propylene, and the α-olefin other than propylene accounts for 10 mol% or less, preferably 7% or less based on the total number of moles of propylene and the other α-olefin. And random copolymers of other α-olefins.
As the α-olefin other than propylene, usually an α-olefin having 20 or less carbon atoms, specifically ethylene, 1-butene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene, 1 -Tetradedecene, 1-octadecene, etc. are used, and each is used individually or in mixture of 2 or more types.
The MFR (230 ° C., 2.16 kg load) of the propylene-based polymer is preferably 0.1 to 50 g / 10 minutes, and more preferably 5.0 to 30 g / 10 minutes.
The density is preferably ^{0.880~0.910g / cm 3, 0.880~0.900g / cm} 3 is more preferable.
The amount of unsaturated carboxylic acid or its derivative (graft monomer) grafted onto the polyolefin is usually 0.01 to 10% by weight, preferably 0.1 to 5% by weight. In the case of such a graft amount, the adhesiveness between the base material layer (X) and the layer (Y) containing the polymer (a) is good and preferable.

  Examples of the unsaturated carboxylic acid include acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid and the like. Unsaturated carboxylic acid derivatives are acid anhydrides, esters, amides, imides, metal salts, etc., such as maleic anhydride, citraconic anhydride, itaconic anhydride, methyl acrylate, methyl methacrylate, ethyl acrylate, methacrylic acid. Ethyl acetate, butyl acrylate, butyl methacrylate, glycidyl acrylate, glycidyl methacrylate, maleic acid monoethyl ester, maleic acid diethyl ester, fumaric acid monomethyl ester, fumaric acid dimethyl ester, itaconic acid monomethyl ester, itaconic acid diethyl ester, Acrylamide, methacrylamide, maleic acid monoamide, maleic acid diamide, maleic acid-N-monoethylamide, maleic acid-N, N-diethylamide, maleic acid-N-monobutylamide, maleic acid-N, N- Butyramide, fumaric acid monoamide, fumaric acid diamide, fumaric acid-N-monoethylamide, fumaric acid-N-monobutyramide, fumaric acid-N, N-dibutyrylamide, maleimide, N-phenylmaleimide, sodium acrylate, Examples include sodium methacrylate, potassium acrylate, and potassium methacrylate.

  Further, epoxy group-containing derivatives include mono- and diglycidyl esters of maleic acid, mono- and diglycidyl esters of fumaric acid, mono- and diglycidyl esters of crotonic acid, mono- and di-glycols of tetrahydrophthalic acid, such as glycidyl acrylate and glycidyl methacrylate Glycidyl esters, mono and glycidyl esters of itaconic acid, mono and diglycidyl esters of butenetricarboxylic acid, mono and diglycidyl esters of citraconic acid, endo-cis-bicyclo [2.2.1] hept-5-ene-2,3- Mono- and diglycidyl esters of dicarboxylic acids (Nadic acid TM), mono- and di-glycosyl esters of endo-cis-bicyclo [2.2.1] hept-5-ene-2-methyl-2,3-dicarboxylic acid (Methyl nadic acid TM) Glycidyl ester, allyl succinic acid Mono- and glycidyl esters of dicarboxylic acids such as mono- and glycidyl esters (C1-C12 of alkyl groups in the case of mono-glycidyl esters), alkyl glycidyl esters of p-styrene carboxylic acid, allyl glycidyl ether, 2-methylallyl glycidyl ether , Styrene-p-glycidyl ether, 3,4-epoxy-1-butene, 3,4-epoxy-3-methyl-1-butene, 3,4-epoxy-1-pentene, 3,4-epoxy-3- Examples thereof include methyl-1-pentene, 5,6-epoxy-1-hexene, vinylcyclohexene monoxide and the like. Hydroxyl-containing derivatives include hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxy-3-phenoxy-propyl (meth) acrylate, 3-chloro-2 -Hydroxypropyl (meth) acrylate, glycerin mono (meth) acrylate, pentaerythritol mono (meth) acrylate, trimethylolpropane mono (meth) acrylate, tetramethylolethane mono (meth) acrylate, butanediol mono (meth) acrylate, polyethylene (Meth) acrylic acid esters such as glycol mono (meth) acrylate and 2- (6-hydroxyhexanoyloxy) ethyl acrylate; 10-undecen-1-ol, 1-octen-3-ol, 2-methanol Norbornene, hydroxystyrene, hydroxyethyl vinyl ether, hydroxybutyl vinyl ether, N-methylol acrylamide, 2- (meth) acryloyloxyethyl acid phosphate, glycerol monoallyl ether, allyl alcohol, allyloxyethanol, 2-butene-1,4 -Diol, glycerin monoalcohol and the like.

  Among these, unsaturated carboxylic acids or acid anhydrides thereof, particularly dicarboxylic acids or acid anhydrides thereof are preferred, and maleic acid, nadic acid or acid anhydrides thereof, maleic anhydride, hydroxyethyl (meth) acrylate Suitable examples include glycidyl methacrylate, aminopropyl methacrylate, glycidyl maleate, hydroxyethyl (meth) acrylate, hydroxyethyl (meth) acrylate, glycidyl (meth) acrylate, aminoethyl methacrylate, and aminopropyl methacrylate. it can.

In order to produce a graft-modified propylene polymer or other modified polyolefin by graft copolymerization of these unsaturated ethylenic monomers with a propylene-based polymer or other polyolefin, various conventionally known methods can be employed. .
For example, there are a method in which a propylene-based polymer is melted and a graft monomer is added to carry out graft copolymerization, or a method in which it is dissolved in a solvent and a graft monomer is added to carry out graft copolymerization. In any case, in order to efficiently graft copolymerize the graft monomer, it is preferable to carry out the reaction in the presence of a radical initiator. The grafting reaction is usually performed at a temperature of 60 to 350 ° C. The use ratio of the radical initiator is usually in the range of 0.001 to 1 part by weight with respect to 100 parts by weight of the polyolefin.

As radical initiators, organic peroxides, organic peroxides such as dicumyl peroxide, di-tert-butyl peroxide, 2,5-dimethyl-2,5-di (tert-butylperoxy) hexyne-3, 2,5- Dialkyl peroxides such as dimethyl-2,5-di (tert-butylperoxy) hexane and 1,4-bis (tert-butylperoxyisopropyl) benzene are preferred.
The thickness of the layer (Z) made of the modified polyolefin is usually 0.01 to 5.0 μm, preferably 0.01 to 3.0 μm, more preferably 0.01 to 2.0 μm. More excellent adhesion.

Ionomer resin The ionomer resin used in the present invention is a copolymer of an olefin represented by ethylene and an α, β-ethylenically unsaturated carboxylic acid or a derivative thereof, or a graft of an unsaturated carboxylic acid of an olefin polymer or a derivative thereof. A free carboxyl group in the copolymer is completely or partially neutralized with an alkali metal such as sodium or potassium or an alkaline earth metal such as zinc. These are resins in which all or part of the carboxyl groups are neutralized with a metal such as sodium or zinc. Since the ionomer resin has an ionic group, it has the property of self-dispersing in water when the melt is stirred and mixed in hot water using a device such as a homomixer. Easy to form.

  When using this ionomer resin as a layer (Z) which consists of adhesive resin (c), it is good also as a mixture of an ionomer resin and a polyvinyl alcohol-type polymer. In this case, the ratio of the ionomer resin to the polyvinyl alcohol polymer is 100: 0 to 20:80, preferably 100: 0 to 30:70, and more preferably 100: 0 to 40:60, If it is this range, the adhesiveness of the base material layer (X) and the layer (Y) containing a polymer (a) will be more excellent.

The mixture of the ionomer resin and the polyvinyl alcohol polymer may be a mixture of an ionomer resin aqueous dispersion and a polyvinyl alcohol polymer aqueous solution.
In the present invention, an ionomer resin aqueous dispersion or a mixture of an ionomer resin aqueous dispersion and an aqueous polyvinyl alcohol polymer solution is a solvent other than water, for example, alcohols such as methanol, ethanol, isopropanol, acetone, methyl ethyl ketone, etc. These ketones, or other diethyl ether, tetrahydrofuran and the like can be added alone or in combination of two or more as required.

  When an ionomer resin or a mixture of an ionomer resin and a polyvinyl alcohol polymer is used as an adhesive resin, the thickness of the layer (Z) made of the adhesive resin (c) is usually 0.01 to 5.0 μm, preferably It is 0.01-3.0 micrometers, More preferably, it is 0.01-2.0 micrometers, and if it is this range, adhesiveness will be more excellent.

Protective layer In the stretched molded product such as the stretched film of the present invention, a protective layer may be further laminated on the layer (Y) containing the polymer (a).
The protective layer is not particularly limited as long as it can protect the layer (Y) containing the polymer (a), and various known protective layers such as a poxy resin, an unsaturated polyester resin, and a phenol resin. , Thermosetting resins such as urea / melamine resin, polyurethane resin, silicone resin, amino resin, polyimide, polyolefin (polyethylene, polypropylene, poly-4-methyl / 1-pentene, polybutene, etc.), polyester (polyethylene terephthalate, polybutylene terephthalate) , Polyethylene naphthalate, etc.), polyamide (nylon-6, nylon-66, polymetaxylene adipamide, etc.), polyvinyl chloride, polyimide, ethylene / vinyl acetate copolymer or saponified product thereof, polyvinyl alcohol, polyacrylonitrile, Polycarbonate DOO, polystyrene, ionomer or thermoplastic resins such as these mixtures, and the like.

  The stretched film of the present invention is usually used as a laminate in which a layer (Y) excellent in gas barrier properties is laminated on a base material layer (X). Such a gas barrier laminate can take various shapes such as a laminate film, a laminate sheet, a tray, a cup, and a hollow body (bottle) depending on the shape of the base material layer (X) and depending on the application.

A stretched film having a gas barrier property obtained by the production method of the present invention is laminated on at least one surface thereof to obtain a laminated film suitable as a heat-sealable packaging film. As such a heat-fusible layer, a homo- or copolymer of α-olefin such as ethylene, propylene, butene-1, hexene-1, 4-methylpentene-1, octene-1, etc., which are generally known as heat-fusible layers , High pressure method low density polyethylene, linear low density polyethylene (so-called LLDPE), high density polyethylene, polypropylene, polypropylene random copolymer, polybutene, poly-4-methyl pentene-1, low crystalline or amorphous ethylene Polypropylene random copolymer, ethylene / butene-1 random copolymer, polyolefin such as propylene / butene-1 random copolymer, or a composition of two or more, ethylene / vinyl acetate copolymer (EVA), ethylene・ (Meth) acrylic acid copolymer or metal salt thereof, EVA and polyolefin A layer obtained from the object or the like.
Among these, a heat-sealing layer obtained from an ethylene-based polymer such as high-pressure method low-density polyethylene, linear low-density polyethylene (so-called LLDPE), or high-density polyethylene is preferable because it has excellent low-temperature heat sealability and heat seal strength.

Further, a protective layer may be formed on the surface of the stretched film containing the polymer (a) by a variety of conventionally known methods on the surface thereof.
For example, when forming a protective layer made of a thermosetting resin, a method in which a monomer or prepolymer is coated on the layer (Y) containing the polymer (a) and then cured, and a protective material made of a thermoplastic resin In the case of forming a layer, a method of drying after applying a solution or emulsion of a thermoplastic resin may be employed.

  EXAMPLES Next, although an Example demonstrates this invention further more concretely, this invention is not limited at all by these Examples.

The physical property values and the like in Examples and Comparative Examples are obtained by the following evaluation methods.
<Evaluation method>
(1) Oxygen permeability [ml / (m ² · day · MPa)]: The stretched film is OX-TRAN 2/21 ML manufactured by Mocon, according to JIS K 7126, temperature 20 ° C., humidity 90% R . H. Measure under the following conditions.
(2) Absorbance ratio (A ₀ / A): measured by the method described above.
(3) Polymerization rate: [1- (A ₁ / A) _{after UV} / (A ₁ / A) _monomer ] × 100
* _(A 1 / _{A) after UV:} ultraviolet irradiation (after polymerization) after _(A 1 / A)
* _(A 1 / A) _monomer: monomer (before polymerization) of _(A 1 / A)
(A ₁ / A) was defined as described below.
Ratio of absorbance A ₁ based on δC—H of hydrogen bonded to a vinyl group near 830 cm ⁻¹ to absorbance A based on νC═O of carboxylate ions near 1520 cm ⁻¹ in the infrared absorption spectrum (A ₁ / A) Cut out a sample for measurement of 1 cm × 3 cm from the stretched film, and obtained an infrared absorption spectrum of the surface (layer (Y) containing the polymer (a)) by infrared total reflection measurement (ATR method). First, the absorbance A ₁ and the absorbance A are obtained.

830cm absorbance based .delta.C-H of hydrogen binding to vinyl groups in the vicinity of ^-1 _{A 1:} bear and the absorbance of the infrared absorption spectrum of 800 cm ^-1 and 850 cm ^-1 in a straight line (P), between 800～850Cm ^-1 A straight line (Q) is dropped vertically from the maximum absorbance (near 830 cm ⁻¹ ), and the distance (length) of absorbance between the intersection of the straight line (Q) and the straight line (P) and the maximum absorbance is defined as absorbance A ₁ .
1520 cm ^-1 vicinity of carboxylate ion of νC = O based upon the absorbance A: connected by a straight line (L) and the absorbance of the infrared absorption spectrum of 1480 cm ^-1 and 1630 cm ^-1, the maximum absorbance between 1480~1630cm ^{-1 (1520cm The} straight line (M) was dropped vertically from the vicinity of ⁻¹ ), and the absorbance distance (length) between the intersection of the straight line (M) and the straight line (L) and the maximum absorbance was defined as absorbance A. The peak position of maximum absorbance (near 1520 cm ⁻¹ ) may vary depending on the metal species of the counter ion. For example, calcium is near 1520 cm ⁻¹ , zinc is near 1520 cm ⁻¹ , and magnesium is near 1540 cm ⁻¹ . is there.
Next, the ratio (A ₁ / A) is determined from the absorbance A ₁ and the absorbance A determined by the above method. Further, the polymerization rate is determined by measuring the monomer absorbance ratio (A ₁ / A) _monomer and the UV irradiation (after polymerization) (A ₁ / A) _{after UV} .
In addition, the measurement of the infrared spectrum (infrared total reflection measurement: ATR method) in the present invention uses an FT-IR350 apparatus manufactured by JASCO Corporation, and a KRS-5 (Thallium Bromide-Iodide) crystal is attached, and the incident angle is 45. Degree, room temperature, resolution of 4 cm ⁻¹ , and 150 times of integration.

<Preparation of solution (s1)>
Aqueous solution of zinc acrylate (Zn salt of acrylic acid) [Asada Chemical Co., Ltd., concentration: 15 wt% (acrylic acid component: 10 wt%, Zn component: 5 wt%)] and methyl alcohol diluted to 25 wt% Photopolymerization initiator [1- [4- (2-hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl-1-propan-1-one (trade name; Irgacure 2959, manufactured by Ciba Specialty Chemicals) ] And a surfactant (trade name; Emulgen 120 manufactured by Kao Corporation) are mixed so that the molar fractions are 98.5%, 1.2%, and 0.3%, respectively, and the unsaturated carboxylic acid compound Zn salt solution is mixed. (S1) is produced.

<Preparation of solution (s2)>
A 15% aqueous solution of a polyvinyl alcohol polymer having a polymerization degree of 1000, an ethylene content of 8.6 mol%, and a saponification degree of 95% or more is prepared.

<Preparation of solution (s3)>
A 15% aqueous solution of silyl-modified polyvinyl alcohol resin, R1130 (manufactured by Kuraray Co., Ltd.) is prepared.

Example 1
An unsaturated carboxylic acid compound Zn salt solution (s1) is applied to the surface of an unstretched film made of polyethylene terephthalate using a Mayer bar so that the coating amount after drying is 10 g / m ² . Next, the whole unstretched film was dried in an oven at 60 ° C. for 1 minute, and then irradiated to the whole unstretched film so as to have an irradiation light amount of 5 mJ / cm ² by using an ultraviolet irradiation device, and prepolymerized. The polymerization rate of the polymer layer applied at this time was 35%. Next, the stretched film was biaxially stretched (stretching ratio: 1.5 × 1.5 times), and further irradiated with ultraviolet rays so as to have an irradiation light amount of 200 mJ / cm ^2. A formed stretched film was obtained. The absorbance ratio (A ₀ / A) was 0.1. Further, when a sample was cut out from the stretched film with a size of 90 mm × 90 mm and its oxygen permeability was measured, it was 1 ml / m ² · day · MPa.

Example 2
Polypropylene having a melt flow rate of 2.0 g / 10 min was melted in an extruder and extruded from a T-die into a sheet to obtain an unstretched sheet. This unstretched sheet was stretched 5 times by a longitudinal stretching machine composed of heating roll groups having different peripheral speeds, and then one side of the longitudinally stretched sheet was subjected to corona discharge treatment. Next, the solution s1 and the solution s2 are mixed so that the solid content ratio (wt%) is 5 (s1): 95 (s2), and this mixed solution is dried on the corona surface of the longitudinally stretched sheet. After coating and drying so as to be 20 g / m ² , it is continuously introduced into a tenter transverse stretching machine and stretched transversely at a stretching ratio of 10 times, and then further irradiated with ultraviolet rays so that the irradiation light quantity becomes 200 mJ / cm ^2. A laminated film was obtained. The absorbance ratio (A ₀ / A) was 0.1, and the oxygen permeability measured was 100 ml / m ² · day · MPa.

Example 3
The same polypropylene resin as used in Example 2 was melted in an extruder and extruded from a T-die into a sheet to obtain an unstretched sheet. This unstretched sheet was stretched 5 times by a longitudinal stretching machine composed of heating roll groups having different peripheral speeds, and then one side of the longitudinally stretched sheet was subjected to corona discharge treatment. Next, an aqueous dispersion of ionomer resin (Mitsui Chemicals Chemipearl S100) was applied as an adhesive resin layer so that the coating film after drying had a thickness of 1 μm, dried with warm air, and continuously in a tenter transverse stretching machine. The film was introduced and transversely stretched at a stretch ratio of 10 to obtain an ionomer resin laminated film. Next, the solution s1 and the solution s3 are mixed so that the solid content ratio (wt%) is 87.5 (s1): 12.5 (s3), and this mixed solution is placed on the ionomer resin of the ionomer resin laminated film. The coated film after drying was applied to 3.5 g / m ² , dried at 40 ° C. for 15 seconds, and then irradiated with ultraviolet rays to an irradiation light amount of 200 mJ / cm ² to obtain a laminated film. The absorbance ratio (A ₀ / A) was 0.1, and the oxygen permeability measured was 1.5 ml / m ² · day · MPa.

Example 4
A laminated film was obtained in the same manner as in Example 3 except that the solution applied onto the ionomer resin laminated film was changed to s1. The absorbance ratio (A ₀ / A) was 0.12, and the oxygen transmission rate was 1.0 ml / m ² · day · MPa.

Example 5
The same polypropylene resin as used in Example 2 was melted in an extruder and extruded from a T-die into a sheet to obtain an unstretched sheet. This unstretched sheet was stretched 5 times by a longitudinal stretching machine composed of heating roll groups having different peripheral speeds, and then one side of the longitudinally stretched sheet was subjected to corona discharge treatment. Next, an aqueous dispersion of ionomer resin (Mitsui Chemicals Chemipearl S100) was applied as an adhesive resin layer so that the dried coating film had a thickness of 1 μm and dried with warm air. Next, the solution s1 and the solution s2 are mixed so that the solid content ratio (wt%) is 5 (s1): 95 (s2), and this mixed solution is dried on an ionomer resin so that the coating film after drying is 20 g / m 2. After coating and drying so as to be ² , the film was continuously introduced into a tenter transverse stretching machine and transversely stretched at a stretching ratio of 10 times, and further irradiated with ultraviolet rays so as to have an irradiation light amount of 200 mJ / cm ² to obtain a laminated film. It was. The absorbance ratio (A ₀ / A) was 0.13, and the oxygen permeability was measured to be 110 ml / m ² · day · MPa.

Example 6
Crystalline polypropylene resin (II value: 98.6%) (X2) blended with the same polypropylene resin (X1) and petroleum resin (softening point 135 ° C.) as used in Example 2, and anhydrous maleic resin Modified polypropylene grafted with acid (Mitsui Chemicals Admer QF500) (X3) is melted in a separate extruder and layered (in the order of (X1) / (X2) / (X3)) in one die. Extrusion gave an unstretched three-layer sheet. This unstretched sheet was stretched 5 times by a longitudinal stretching machine composed of heating roll groups having different peripheral speeds, and subsequently, the (X3) plane of this longitudinally stretched sheet was subjected to corona discharge treatment. Next, the solution s1 and the solution s2 are mixed so that the solid content ratio (wt%) is 5 (s1): 95 (s2), and this mixed solution is dried on the corona surface of the longitudinally stretched sheet. After coating and drying so as to be 20 g / m ² , it is continuously introduced into a tenter transverse stretching machine and stretched transversely at a stretching ratio of 10 times, and then further irradiated with ultraviolet rays so that the irradiation light quantity becomes 200 mJ / cm ^2. A laminated film was obtained. The absorbance ratio (A ₀ / A) was 0.15, and the oxygen permeability was measured to be 98 ml / m ² · day · MPa.

Comparative Example 1
Polypropylene having a melt flow rate of 2.0 g / 10 min was melted in an extruder and extruded from a T-die into a sheet to obtain an unstretched sheet. This unstretched sheet was stretched 5 times by a longitudinal stretching machine composed of heating roll groups having different peripheral speeds, and then one side of the longitudinally stretched sheet was subjected to corona discharge treatment. Next, the solution s1 is applied onto the corona surface of the longitudinally stretched sheet so that the coating film after drying is 20 g / m ² , dried at 40 ° C. for 15 seconds, and further irradiated with ultraviolet rays so that the irradiation light quantity becomes 200 mJ / cm ^2. Irradiated, continuously introduced into a tenter transverse stretching machine and transversely stretched at a stretch ratio of 10 times to obtain a laminated film. The absorbance ratio (A ₀ / A) was 0.15, and the oxygen permeability measured was 2000 ml / m ² · day · MPa or more.

The stretched film on which the polymer layer of the unsaturated carboxylic acid compound polyvalent metal salt of the present invention is formed is excellent in gas barrier properties under high humidity, and by utilizing such characteristics, it is used with stretched films for various applications. Is done.

Claims (10)

A solution (s) containing an unsaturated carboxylic acid compound polyvalent metal salt having a polymerization degree of less than 20 is applied to at least one surface of the unstretched base material layer (X), and at the same time and / or stretching process. And a layer (Y) containing the polymer (a) of the unsaturated carboxylic acid compound polyvalent metal salt is formed after the step. A solution (s) containing an unsaturated carboxylic acid compound polyvalent metal salt having a degree of polymerization of less than 20 is applied to at least one surface of the unstretched base material layer (X), and the unsaturated carboxylic acid compound polyvalent metal salt is coated. Is prepolymerized to form a layer (Y) containing the prepolymer (a ′), and then the layer (Y) containing the prepolymer (a ′) and the unstretched substrate layer (X) And a layer (Y) containing a polymer (a) of an unsaturated carboxylic acid compound polyvalent metal salt, during the stretching, or thereafter, further polymerizing the prepolymer (a ′). The method for producing a stretched molded product according to claim 1 , wherein: A solution (s) containing an unsaturated carboxylic acid compound polyvalent metal salt having a polymerization degree of less than 20 is applied to at least one surface of the unstretched base material layer (X), and the unstretched base material layer (X) And the layer (Y) containing the polymer (a) are stretched together, and then the unsaturated carboxylic acid compound polyvalent metal salt polymer is polymerized by polymerizing the unsaturated carboxylic acid compound polyvalent metal salt ( method for producing a stretch molded article according to claim 1, characterized in that to form a layer (Y) containing a). The method for producing a stretched molded product according to any one of claims 1 to 3 , wherein the base material layer (X) on which a layer of the adhesive resin (c) is previously laminated is used. The solution (s) is the degree of polymerization subjected unsaturated carboxylic acid compound polyvalent metal salt of less than 20, to one of 4 claims 1, characterized in that it contains the vinyl alcohol polymer (b) The manufacturing method as described. Unsaturated carboxylic acid compound to form an unsaturated carboxylic acid compound polyvalent metal salt is stretched according to any one of claims 1 to 5 monomer or polymerization degree of 10 or less of a polymer of an unsaturated carboxylic acid Manufacturing method of a molded object. The method for producing a stretched molded product according to any one of claims 1 to 6 , wherein the unsaturated carboxylic acid compound is (meth) acrylic acid. The method for producing a stretched molded product according to any one of claims 1 to 7 , wherein the polyvalent metal salt of the unsaturated carboxylic acid compound is polymerized in the presence of moisture. The method for producing a stretched molded product according to any one of claims 1 to 8 , wherein a protective layer is formed on the layer (Y) of the polymer (a) of the unsaturated carboxylic acid compound polyvalent metal salt. . Stretched film obtained al is by the production method according to any one of claims 1 to 9.