JPH11538A - Selectively gas permeable film and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a selectively gas permeable film having a high ratio of CO2 permeability to O2 permeability and capable of controlling O2 permeability by using a polymer having at least specified structural units in its molecule. SOLUTION: The selectively gas permeable film is made of a polymer having at least structural units represented by formula I in its molecule. In the formula I, R1 is a substituent contg. an amino group or an amino group, plural R1 's in the polymer may be different from each other and R1 is preferably at least one substituent represented by the formula -(CH2 )x -NH2 [where (X) is 0 or an integer of 1-6] and may be a substituent having an amino group contg. an arom. ring or an aliphatic group having an unsatd. bond. Polyvinylamine having -NH2 as R1 or polyallylamine having (CH2 )-NH2 as R1 is especially preferably used as the polymer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas-permeable film comprising a polymer having an amino group-containing substituent or an amino group in a molecule. More specifically, the present invention relates to a film characterized in that the ratio between the carbon dioxide gas permeability and the oxygen gas permeability is large.

[0002]

2. Description of the Related Art As a membrane having high selective permeability to carbon dioxide gas, Journal of Membrane S is known.
Science (Journal of Membrane Science), 6 (1980), pp. 339-343, on a cation exchange membrane in which polystyrene is grafted onto a polytetrafluoroethylene backbone polymer and sulfonic acid groups are introduced, and a carbon dioxide gas carrier is used. A membrane having a high ratio of carbon dioxide gas permeability to nitrogen gas permeability, in which ethylene diamine, which has been cationized to valence, is electrostatically retained is shown.

[0003] Also, the membrane symposium No. 5 (199
3) Kyoto, Abstracts, pp. 73-75, describes methacrylic acid 2-containing tertiary amine as a fixed carrier.
(N, N-Dimethylamino) ethyl was selected, acrylonitrile and 2-ethylhexyl methacrylate were used as comonomers, and radical copolymerization was performed to obtain a film material, and the oxygen gas permeability and nitrogen gas permeability of the film material were obtained. It has been reported that the polymer membrane selectively permeates carbon dioxide by comparing carbon dioxide gas permeability with carbon dioxide gas permeability. Furthermore, abstracts of the 58th Annual Meeting of the Chemical Engineering Society, vol. 1,
On page 269, an ion-exchange membrane obtained by plasma-grafting acrylic acid onto a polyethylene porous membrane is immersed in an aqueous solution of ethylenediamine, and the membrane in which a monocationic substance of ethylenediamine is introduced therein selectively permeates carbon dioxide. Is described. However, the separation membranes disclosed therein have problems such as economy and productivity.

Japanese Patent Application Laid-Open No. 61-101203 discloses an invention relating to a highly permeable composite membrane comprising a porous support coated with a crosslinked polymer containing polyallylamine as a main component. And a semipermeable membrane for selectively permeating and separating the component (1). JP-A-6-23
No. 9926 discloses that a coating solution containing polyvinylamine composed of 3 to 100 mol% of a vinylamine unit and 97 to 0 mol% of a nonionic monomer unit is applied to at least one surface of a base film and then stretched. An antistatic film is disclosed.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a film having a selective gas permeability having a large ratio between the carbon dioxide gas permeability and the oxygen gas permeability and capable of controlling the oxygen gas permeability. To provide.

[0006]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to achieve the above object, and have found that a polymer having at least a substituent having an amino group or a specific structural unit having an amino group in a molecule. It has been found that the resulting film has a large ratio between the carbon dioxide gas permeability and the oxygen gas permeability, thereby completing the present invention.

That is, the present invention provides a gas-permselective film comprising a polymer having at least a structural unit represented by the following formula (1) in a molecule.

[0008]

Embedded image

Further, the present invention relates to the above formula (1)
₁ is _{- (CH 2) X -NH 2} (X is from 0 or an integer of 1 6) to provide a film having a gas permselective is at least one substituent represented by.

Further, the present invention provides a gas-permselectable film comprising a polymer having at least a structural unit represented by the following formula (2) in a molecule.

[0011]

Embedded image

In the formula (2), R ₂ is-(C
H ₂ ) _X— NH ₃ ⁺ L ⁻ (X represents 0 or an integer of 1 to 6, and L represents an anion forming L ⁻¹ ). A film having a selective gas permeability. Furthermore, the present invention provides a film having the above-mentioned gas selective permeability including a substrate layer. The present invention has gas selective permeability obtained by applying a coating liquid comprising a polymer having at least a structural unit represented by the formula (1) or (2) in a molecule to a base layer and drying the coating liquid. Provided is a method for manufacturing a film.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. In the present invention, as a polymer having at least a structural unit represented by the formula (1) in a molecule, R ₁ in the formula (1) is — (CH ₂ ) _X —NH ₂ (X is 0 or 1 to 6). Is preferably at least one substituent represented by the following formula: R ₁ may be a substituent having an amino group including an aromatic ring or an aliphatic group having an unsaturated bond.
Among them, polyvinylamine wherein R ₁ is —NH ₂ ,
X is 1, i.e., R ₁ is - (CH ₂₎ polyallylamine is especially preferably -NH _2. A plurality of R ₁ in the above polymer may be different from each other.

At least a structural unit represented by the formula (2)
In the polymer having in the molecule, R_TwoFormed salt
Represents a substituent containing an amino group;_TwoIs-(CH_Two)_X
-NH_Three ⁺L^-(X represents 0 or an integer of 1 to 6;
Is L^-1Represents an anion that forms
Both are preferably one type of substituent. R_TwoIs -NH_Three
⁺L^-X is a polyvinylamine salt (eg, hydrochloride)
1, ie, R_TwoIs-(CH_Two) -NH_Three ⁺L^-Is
Polymers such as polyallylamine salts (eg hydrochloride)
More preferred.

Further, as an example of the polymer which is included in the range of the polymer having at least the structural unit represented by the formula (2) in the molecule, a polymer having the structural unit represented by the formula (1) in the molecule: And a polymer containing in its molecule a structural unit represented by the following (3) obtained by partially neutralizing Here, m and n are positive integers and are related to the degree of polymerization and the degree of neutralization.

[0016]

Embedded image

The ratio of m and n (degree of neutralization) is not particularly limited. The oxygen gas permeability of the product film decreases when the degree of neutralization (degree of neutralization) is low (that is, the oxygen barrier property is large), and increases when the degree of neutralization (degree of neutralization) increases. By doing so, the oxygen gas permeability of the product can be adjusted to a range suitable for the use of the product.

The polymer having at least the structural units represented by the formulas (1) and (2) in the molecule has a number average molecular weight of 1,
500 to 500,000, even 5000 to 40
It is preferably in the range of 000. When the number average molecular weight is lower than this range, the film forming property of the obtained product or the mechanical strength of the obtained film is reduced, or, if too high, the film forming property is deteriorated, and the product becomes difficult to handle. Problems are more likely to occur. Examples of the type of salt include hydrochloride, bromate (hydrobromide), acetate and the like.

In another embodiment of the present invention, the film having gas permeability is preferably a laminated film having a substrate layer. As a material constituting the base layer, at least one material selected from a film made of a thermoplastic resin, a film made of a thermosetting resin, paper, a woven fabric, a nonwoven fabric, a porous metal material or an inorganic sintered porous material is used. preferable.
The substrate layer can be appropriately selected in consideration of the application and the fact that the gas permeability of the substrate layer does not extremely hinder the gas selective permeation performance of the laminated film.

The raw material of the film made of a thermoplastic resin is not particularly limited.
Films such as polyolefin, polystyrene, polyvinyl chloride, polyamide, polyvinylidene fluoride (PVDF), and polytetrafluoroethylene, and preferably polyester, polyvinylidene fluoride, and polyolefin. Examples of the polyester include polyethylene terephthalate (PET), polyethylene isophthalate, polybutylene terephthalate, poly (1,4-cyclohexylene dimethylene terephthalate), polyethylene 2,6-naphthalenedicarboxylate, and the like, and copolymers thereof, or copolymers thereof. And small amounts of other resins.

Examples of the polyolefin include homopolymers and copolymers of olefins, copolymers of olefins with other copolymerizable monomers such as vinyl monomers, and modified polymers thereof. can do. Specifically, high-density polyethylene, low-density polyethylene (hereinafter abbreviated as “LDPE”), linear low-density polyethylene (hereinafter abbreviated as “LLDPE”), linear ultra-low-density polyethylene (hereinafter “VLDPE”) ), Polypropylene, ethylene-propylene copolymer, poly 4-methylpentene-1 (hereinafter abbreviated as “TPX”), ionomer resin, ethylene-vinyl acetate copolymer (hereinafter “EVA”)
Abbreviation), ethylene-acrylic acid copolymer, ethylene
Methacrylic acid copolymer (hereinafter abbreviated as "EMAA"), ethylene-methyl acrylate copolymer, ethylene-methyl methacrylate copolymer, modified polyolefin (for example,
Reaction products of homo- or copolymers of olefins with unsaturated carboxylic acids such as maleic acid and fumaric acid, acid anhydrides, esters or metal salts). The above olefin copolymers can be used alone or as a mixture of two or more. Among them, TPX, VLD
PE, EVA, EMAA, LLDPE, ethylene / acrylic acid copolymer, and the like are preferable from the viewpoint of the physical properties of the obtained molded product.

Examples of the polyvinylidene fluoride include a homopolymer of vinylidene fluoride, a copolymer containing vinylidene fluoride as a constituent unit in an amount of 70 mol% or more, and a mixture of these polymers. Monomers copolymerized with vinylidene fluoride include ethylene tetrafluoride, propylene hexafluoride, ethylene trifluoride, ethylene trifluoride chloride,
And vinyl fluoride.

The laminated film of this embodiment is a film made of a polymer having an amino group in the molecule (hereinafter referred to as a film M).
And the base material, but the film M may be isolated from the base material in a formed state and used. Also, as another layer configuration,
There is a layer configuration of substrate / film M / substrate. Specific examples include porous PET / film M / LDPE, TPX / film M / EVA, TPX /
Membrane M / porous LLDPE, Porous PVDF / Membrane M / Porous LLD
PE and the like. The thickness of the film M is preferably 1 to 1
00 μm is more preferably 1 to 50 μm.
In addition, when the adhesive force between the base material layer and the film M is particularly desired, an adhesive may be used. The total thickness of the laminated film is preferably from 15 to 400 μm, more preferably from 20 to 200 μm.

The gas-permeable film of the present invention has a ratio of carbon dioxide gas permeability to oxygen gas permeability at a temperature of 23 ° C. and a relative humidity of 80% (carbon dioxide gas permeability / oxygen gas permeability).
But preferably from 10 to 200, more preferably 11
To 200, most preferably 20 to 200. Oxygen gas permeability is preferably 10 to 200,000 cm
³ / cm ² · MPa · s, more preferably 50 to 10
It is in the range of 000 cm ³ / cm ² · MPa · s, most preferably 100 to 50,000 cm ³ / cm ² · MPa · s. The carbon dioxide gas permeability is 100 to 1,000.
000 cm ³ / cm ² · MPa · s, more preferably 500 to 950,000 cm ³ / cm ² · MPa · s
s, most preferably 1000 to 900,000 cm ³ /
cm ² · MPa · s.

As an example of the method for producing the gas selectively permeable film of the present invention, a polyvinylamine aqueous solution is used as a substrate PV
It is applied to a predetermined thickness on a DF porous membrane (thickness: 110 μm, porosity: 75%), and dried at 70 to 110 ° C. Thus, a film can be easily obtained.

Since the obtained film can have a large ratio of carbon dioxide gas permeability to oxygen gas permeability, various kinds of CO ₂ separation membranes, fruits and vegetables (garlic, yam, etc.) which generate carbon dioxide, It is preferably used for packaging fermented foods (cheese, kimchi, raw miso, etc.).

[0027]

EXAMPLES The present invention will now be described specifically with reference to examples, but the present invention is not limited to these examples. (Measurement of oxygen gas and carbon dioxide gas permeability) The oxygen gas and carbon dioxide gas permeability of the laminate were measured using a mixed gas permeability measuring device (GL Science Co., Ltd., film double-sided humidified gas permeability tester). The measurement was performed at 23 ° C. and a relative humidity of 80%. The test gas is a mixed gas (CO ₂ : O ₂ = 2)
0: 80% by volume). A gas chromatograph (GC-39) manufactured by GL Science Co., Ltd. is used as the permeated gas detector.
0), PorapakN was used for the column. (Ratio between carbon dioxide gas permeability and oxygen gas permeability) It was determined by dividing the carbon dioxide gas permeability obtained by the above-mentioned measuring method by the oxygen gas permeability. The gas selective permeability was evaluated from this ratio.

Example 1 and Comparative Example 1 10% by weight of polyallylamine (hereinafter referred to as "PALA")
Aqueous solution Paa-H (manufactured by Nitto Boseki Co., Ltd., average molecular weight 1)
00,000: dialysis treated product). This aqueous solution
A 110 μm thick PVDF porous membrane (Millipore, average pore size 0.22 μm, porosity 75%) was applied using a Mayer bar. This was placed in a drier and dried at 90 ° C. for 20 minutes to evaporate water to produce a film in which a 5-μm thick sheet made of PALA was applied on a PVDF porous membrane substrate. The gas permeability of carbon dioxide gas and oxygen gas of the thus obtained film (laminated film) and the PALA film (membrane M) alone, and the carbon dioxide gas permeability / oxygen gas permeability ratio were determined. The gas permeability of the PALA membrane (membrane M) alone was calculated from the value of the gas permeability of the PVDF porous membrane used as the base material as follows: 1 / P (total) = 1 / P (fil
m) Calculated by + 1 / P (sub). Where P (total)
Is the gas permeability of the entire laminate, P (film) is the gas permeability of the film M, and P (sub) is the gas permeability of the substrate. PV
Both the carbon dioxide gas permeability and the oxygen gas permeability of the DF porous membrane were 1 × 10 ⁸ cm ³ / cm ² · MPa · s (Comparative Example 1). Table 1 shows the permeability of carbon dioxide gas and oxygen gas, and the ratio of the permeability of carbon dioxide gas to the permeability of oxygen gas. In addition, in Table 1, the laminated film was indicated as a laminated body, and the gas permeability of the substrate of the comparative example was shown in the column of the gas permeability of the laminated body.

Example 2 Polyvinylamine (hereinafter referred to as "polyvinylamine")
As "PVLA"), 12% by weight PVAM05
95B, an unneutralized product (manufactured by Mitsubishi Chemical Corporation, number average molecular weight 60,000) was used. Using this aqueous solution, a film in which a 5 μm-thick sheet made of PVLA was applied on a PVDF porous membrane substrate in the same manner as in Example 1 was produced. The gas permeability was measured in the same manner as in Example 1. The results are shown in Table 1.

Example 3 As a polyvinylamine-hydrochloride (hereinafter referred to as "PVLA-HCL"), a 12% by weight neutralized product (manufactured by Mitsubishi Chemical Corporation, PVAM0595)
B number average molecular weight of 60,000) was used. This aqueous solution was applied onto a PVDF porous membrane substrate in the same manner as in Example 1
A film coated with a 5 μm-thick sheet made of VLA-HCL was produced. The gas permeability was calculated in the same manner as in Example 1. The results are shown in Table 1.

(Examples 4 and 5) The aqueous polyvinylamine solution and the aqueous solution of polyvinylamine-hydrochloride used in Examples 2 and 3 were prepared in such a manner that sodium formate derived from the production method was equimolar to an amino group in PVLA and PVLA-HCL. Contains sodium formate in an amount equal to the total number of moles of amino groups and neutralized amino groups. Due to the sodium formate contained, the film consisting of PVLA and the aqueous solution of PVLA-HCL shows a milky white color. This PVLA and PVL
Sodium formate was removed from the A-HCL aqueous solution by dialysis. The dialysis was performed using a regenerated cellulose dialysis tube (Spectra / Pore 7, manufactured by Funakoshi Co., Ltd., molecular weight cut off 2).
PVLA aqueous solution, PVLA
-Each 100 cc of HCl aqueous solution was sealed. next,
These were immersed in 2000 cc of distilled water and dialyzed. The dialysis time was 24 hours, and distilled water was exchanged every 12 hours. The thus obtained PVLA aqueous solution (a dialysis-treated PVLA aqueous solution) and PVLA-HCL
An aqueous solution (aqueous PVLA-HCL solution subjected to dialysis treatment) was applied on a PVDF porous membrane substrate in the same manner as in Example 1 so that the thickness of the dried film became 5 μm, and dried to produce films, respectively ( Examples 4 and 5). The gas permeability was measured in the same manner as in Example 1. The results are shown in Table 1.

(Example 6) The PVLA-HCL aqueous solution subjected to the dialysis treatment used in Example 5 was used, and the thickness of the dried film was 2 on the PVDF porous membrane substrate in the same manner as in Example 5.
It was applied to a thickness of 0 μm and dried to produce a film. The gas permeability was measured in the same manner as in Example 1. The results are shown in Table 1.

Example 7 and Comparative Example 2 The aqueous solution of PALA used in Example 1 (10% by weight aqueous solution Paa-H)
And a 30 μm-thick T
The film was applied on a PX substrate so that the thickness of the dried film became 1 μm, and dried to produce a transparent film in which a PALA film was applied on the TPX substrate. The gas permeability was measured in the same manner as in Example 1. The results are shown in Table 1. In addition, the gas permeability of the TPX sheet as a base material is such that the carbon dioxide gas permeability is 2.260 × 10 ² cm ³ / cm ² · MPa ·
s, and the oxygen gas permeability is 627 × 10 ² cm ³
/ cm ² · MPa · s (Comparative Example 2).

(Embodiment 8) Using the PVLA-HCL aqueous solution subjected to the dialysis treatment used in Embodiment 5 and in the same manner as in Embodiment 7, the thickness of the dried film on the TPX substrate becomes 3 μm. And dried, and PVLA-H on TPX substrate
A transparent film coated with a sheet made of CL was produced. The gas permeability was measured in the same manner as in Example 1.
The results are shown in Table 1.

Example 9 and Comparative Example 3 The film obtained in Example 8 had a thickness of 20 on the side of the PVLA-HCL coating layer.
dry lamination of EVA of 1 μm through an adhesive layer of 1 μm (adhesive: Takelac manufactured by Takeda Pharmaceutical Co., Ltd.) and TPX
A laminated film having a layer configuration of layer / PVLA-HCL layer / adhesive layer / EVA layer (thickness, in order, 30 μm / 3 μm / 1 μm / 20 μm) was manufactured. The gas permeability was measured in the same manner as in Example 1. The results are shown in Table 1. In addition, PVLA
-The gas permeability of the HCL membrane (membrane M) alone is calculated from the gas permeability values of TPX and EVA used for the base material by the following formula: 1 / P (t
otal) = 1 / P (film) + 1 / P (sub1) + 1 / P (sub2)
Calculated based on In the formula, P (sub1) and P (sub2) mean the gas permeability of TPX and EVA, respectively. Further, the gas permeability of EVA is such that the carbon dioxide gas permeability is 770 ×
It was 10 ² cm ³ / cm ² · MPa · s, and the oxygen gas permeability was 156 × 10 ² cm ³ / cm ² · MPa · s (Comparative Example 3).

[0036]

[Table 1]

[0037]

According to the present invention, as described above, the ratio between the carbon dioxide gas permeability and the oxygen gas permeability is high and the oxygen gas permeability is high from the film comprising the polymer having an amino group in the molecule and the substrate. A film having a controlled degree of gas selective permeability can be obtained without a complicated manufacturing process.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Takuya Hiramatsu 18-13 Kamitamari, Tamari-mura, Niigata-gun, Ibaraki Pref.Resin Processing Technology Center, Kureha Chemical Industry Co., Ltd. 18-13 Kamitamari, Kurahama, Kureha Chemical Industry Co., Ltd. Resin Processing Technology Center

Claims (7)

[Claims] 1. A gas-permeable film comprising a polymer having at least a structural unit represented by the following formula (1) in a molecule. Embedded image 2. The gas selective permeability according to claim 1, wherein R ₁ is at least one substituent represented by — (CH ₂ ) _X —NH ₂ (X is 0 or an integer of 1 to 6). Film. 3. A gas-permeable film comprising a polymer having at least a structural unit represented by the following formula (2) in a molecule. Embedded image 4. At least R ₂ is selected from — (CH ₂ ) _X —NH ₃ ⁺ L ⁻ (X represents 0 or an integer of 1 to 6, and L represents an anion forming L ⁻¹ ). The film having gas selective permeability according to claim 3, which is one kind of substituent. 5. A base material layer comprising at least one material selected from the group consisting of a film made of a thermoplastic resin, a film made of a thermosetting resin, paper, a woven fabric, a nonwoven fabric, a porous metal material and a sintered inorganic porous material. The gas-permselective film according to claim 1, comprising: 6. The polymer having an amino group or an amino group forming a salt in the molecule has a number average molecular weight of 1,500 to 5,
The gas-permeable film according to any one of claims 1 to 5, which has a molecular weight of 00000. 7. A gas having a gas selective permeability obtained by applying a coating solution comprising a polymer having at least a structural unit represented by the formula (1) or (2) in a molecule to a base layer and drying the coating solution. Film production method. Embedded image Embedded image