JP7212877B2 - Modified film manufacturing method - Google Patents

Description

The present invention relates to a method for producing modified films.

Olefin polymers are industrially produced by various methods due to their high industrial utility value, and the annual production is said to exceed 100 million tons. Since this olefinic polymer is mainly composed of carbon and hydrogen, it is also characterized by being a stable and inexpensive material. On the other hand, a structure having no functional group has poor affinity with polar materials, and also has properties such as colorability and adhesiveness that are difficult to modify.

Surface treatments such as corona discharge treatment and plasma treatment are known as methods for modifying olefinic polymer films (eg, Patent Document 1).

JP 2003-211814 A

However, in the conventional method for modifying an olefinic polymer film, the molecular weight of the polymer constituting the film tends to decrease, a cross-linking reaction occurs, and deterioration and yellowing of the polymer tend to occur. I found out.
In particular, in the case of a film, a decrease in molecular weight may lead to a decrease in not only strength but also durability, and the narrower molecular weight distribution may make molding difficult.

In addition, for example, a release film, an exterior film, and a display film in which pigments or paints are laid down only in areas where pictures or patterns are to be placed, for example, only a part of the film is modified. Sometimes it's better.
The present inventors thought that if a specific portion (eg, surface) could be mainly modified, it would be possible to increase the modification effect while suppressing a decrease in the strength of the film.

The present invention has been made in view of the above points, and aims to provide a method for producing a modified film in which an olefin polymer film is efficiently modified, preferably mainly at a specific site (eg, surface). aim.

As a result of the research conducted by the present inventors, it was found that the above problems can be solved by the following configuration example. A configuration example of the present invention is as follows.

[1] Atoms (α) of elements selected from group 15 elements and group 16 elements and atoms (β) of group 17 elements in one molecule, number of atoms (α): number of atoms (β) = comprising step 1 of irradiating with light in the presence of radicals in a ratio of 1:1 to 4:1;
A method for producing a modified film by partially or wholly modifying an olefin polymer film having a melting point and/or a glass transition temperature of 50°C or higher and 300°C or lower.

[2] The method for producing a modified film according to [1], wherein the step 1 is a step of modifying the film by irradiating the radicals with light in the presence of the radicals and the film.
[3] The modified fabric according to [1] or [2], wherein the step 1 is a step of modifying the film by irradiating the radicals and the film with light in the presence of the radicals and the film. manufacturing method.

[4] The method for producing a modified film according to any one of [1] to [3], wherein the modified film has a thickness of 1 to 1000 μm.

[5] The method for producing a modified film according to any one of [1] to [4], wherein the radical is a chlorine dioxide radical.

[6] The method for producing a modified film according to any one of [1] to [5], wherein the olefin polymer is a 4-methyl-1-pentene polymer.

[7] The method for producing a modified film according to any one of [1] to [6], wherein the modified film is a porous film.
[8] The method for producing a modified film according to any one of [1] to [7], wherein the modified film is a release film.

According to the production method of the present invention, it is possible to efficiently modify mainly specific portions of the olefin polymer film. Therefore, it is possible to provide a modified film that can suppress the decrease in the molecular weight of the polymer constituting the film, cross-linking reaction, deterioration, yellowing, etc., and has excellent modifying properties and design properties while making the most of the original properties of the film. It is possible.

FIG. 1 is a schematic diagram showing the state of modifying a TPX film in Examples. FIG. 2 is a diagram showing the hydrophilicity evaluation results of TPX films in Examples.

Hereinafter, the present invention will be described more specifically with reference to examples. However, the invention is not limited by the following description.

≪Method for producing modified film≫
The method for producing a modified film according to the present invention (hereinafter also referred to as “this method”) is obtained by modifying a part or all of an olefin polymer film having a melting point and/or a glass transition temperature of 50° C. or more and 300° C. or less. A method for producing a modified film, comprising:
Number of atoms (α): number of atoms (β) = 1:1 It includes step 1 of irradiating in the presence of radicals with a ratio of ~4:1.
In the following, the olefinic polymer film before modification will be simply referred to as "film", and the film after modification will be referred to as "modified film".

According to this method, it is possible to efficiently obtain a modified film in which specific portions such as the surface of the film are mainly modified while maintaining the inherent properties of the film.
Moreover, in the conventional reforming method, the reforming effect tends to deteriorate with time, but according to the present method, suppression of the deterioration with time can be expected.

According to this method, the film can be efficiently denatured (eg, oxidized treatment) by a very simple method of only irradiating the radicals with light, and even under extremely mild conditions such as normal temperature and normal pressure. can be done. Furthermore, according to this method, the film can be efficiently modified (oxidation reaction) without using a radical generator such as a peroxide or an azo compound, which may be unstable at the handling temperature.

<Step 1>
In step 1, atoms (α) of elements selected from group 15 elements and group 16 elements and atoms (β) of group 17 elements are added to one molecule, and the number of atoms (α): the number of atoms (β) It is a step of irradiating light in the presence of radicals contained in a number ratio of 1:1 to 4:1.
The step 1 may be performed by irradiating light in the presence of the radicals, but is preferably a step of irradiating the radicals in the presence of the radicals.

The method for modifying the film is not particularly limited, but a method (I) in which the radicals are irradiated with light in the presence of the radicals and the film [the radicals are irradiated with light in the presence of the radicals and the film to modify the film. denaturation method] is preferred.
As a method for modifying the film, in addition to the method (I), for example, a method (II) in which the system subjected to the step 1 is brought into contact with the film can be used.

In the method (I), the radicals may be irradiated with light, but the radicals and the film are irradiated with light [in the presence of the radicals and the film, the radicals and the film are irradiated with light to irradiate the film. A method of modifying] is also preferable, and a method in which the film is not irradiated with light may be used.
When the radicals and the film are irradiated with light, each of the radicals and the film may be irradiated with light separately, but for example, it is preferable to simultaneously irradiate the radicals and the film with light from one light source. .

The step 1 may be a liquid phase method in which the film is immersed (contacted) in an aqueous phase and/or organic phase containing the radicals, and the film is brought into contact with the aqueous phase and/or organic phase containing the radicals. A vapor phase method may be used in which the reaction is carried out without allowing the reaction to proceed, or a gas phase method may be conducted in a gas phase containing the radicals and the film. Where it matters, gas phase methods are preferred in some circumstances.

The radicals include atoms (α) of elements selected from group 15 elements and group 16 elements and atoms (β) of group 17 elements.
The radical may contain two or more Group 15 element atoms, may contain two or more Group 16 element atoms, and may contain one or more Group 15 element and Group 16 element atoms. It may contain two or more Group 17 element atoms. However, in these cases, the ratio of the numbers of atoms is the ratio of the total number of atoms of the group 15 and 16 elements to the total number of atoms of the group 17 elements.

Atom (α) is preferably nitrogen, oxygen or sulfur, with oxygen being particularly preferred.
The atom (β) preferably includes chlorine, bromine and iodine, with chlorine and bromine being preferred. Among these, chlorine is more preferable because chlorine-containing radicals are easily available. When radicals containing chlorine are used, light containing ultraviolet rays is preferable as irradiation light, and when radicals containing bromine or iodine are used, it is considered that light with a longer wavelength than ultraviolet rays can also be used. Therefore, bromine and iodine are preferable depending on the situation, such as when considering the degree of freedom of light selection or when there is a possibility that the film may be deteriorated by light.

In the radical, the ratio of atoms (α) to one atom (β) in one molecule of the radical is 1 to 4, preferably 1 or 2, more preferably 2.

A chlorine dioxide radical is preferable as the radical.
When light irradiation is performed in the presence of chlorine dioxide radicals (ClO ₂ ·), for example, it is thought that chlorine radicals (Cl ·) and oxygen molecules (O ₂ ) are generated by irradiating the chlorine dioxide radicals with light.

The light (wavelength) used for the light irradiation may be appropriately selected according to the radicals to be used. Specifically, it is possible to select a wide range from the infrared region to the ultraviolet region, and it is, for example, 200 nm or more and, for example, 800 nm or less.
Although the light irradiation time is not particularly limited, it is, for example, 1 minute or more and, for example, 1000 hours or less.

The light source for the light irradiation is not particularly limited, but natural light such as sunlight can be used from the viewpoint of convenience. Further, for example, instead of or in addition to the natural light, a light source such as a xenon lamp, a halogen lamp, a fluorescent lamp, or a mercury lamp may be appropriately used. Furthermore, if necessary, a filter that cuts wavelengths other than the required wavelength may be used as appropriate.

The temperature, pressure, and atmosphere in performing Step 1 are not particularly limited, but the reaction temperature is, for example, 0° C. or higher and, for example, 100° C. or lower, and the pressure is, for example, 0.1 MPa or higher and 100 MPa or lower. The atmosphere includes, for example, an air atmosphere and an inert gas atmosphere.
For example, as shown in the examples below, this method is carried out in the atmosphere at normal temperature (eg, 5 to 35° C.) and normal pressure (atmospheric pressure) without any heating, pressurization, pressure reduction, etc. is also possible.

The light irradiation is performed on radicals existing in the aqueous phase, the organic phase and/or the gas phase. When emphasis is placed on reducing the load on the environment and the effects on the human body, it is preferable to perform the treatment on radicals present in the water phase or the gas phase.

The amount of the film used in the aqueous phase or organic phase when the film is immersed in the aqueous phase or organic phase is not particularly limited, but is, for example, 1 g/L or more with respect to the aqueous phase or organic phase, For example, it is 10 g/L or less.

The aqueous phase is not particularly limited as long as it contains water.

The organic phase is not particularly limited as long as it contains an organic solvent.
Although the organic solvent is not particularly limited, examples thereof include hydrocarbon solvents and halogenated solvents.
One kind of the organic solvent may be used, or two or more kinds thereof may be used.

Examples of the hydrocarbon solvent include, but are not limited to, n-hexane, cyclohexane, benzene, toluene, o-xylene, m-xylene, and p-xylene.

Examples of the halogenated solvent include, but are not limited to, methylene chloride, chloroform, carbon tetrachloride, carbon tetrabromide, and fluorous solvents.

The fluorous solvent refers to a solvent in which all or most of the hydrogen atoms of a hydrocarbon are substituted with fluorine atoms. The fluorous solvent may be, for example, a solvent in which 50% or more, 60% or more, 70% or more, 80% or more, or 90% or more of the hydrogen atoms in the hydrocarbon are substituted with fluorine atoms.

Examples of the fluorous solvent include CF ₃ —(CF ₂ ) _n —CF ₃ (n is 4 to 7), N—((CF ₂ ) _n CF ₃ ) ₃ (n is 1 or 4), hexafluorobenzene , 1-(trifluoromethyl)undecafluorocyclohexane, 1-(trifluoromethyl)pentafluorobenzene, octadecafluorodecahydronaphthalene, among which CF ₃ (CF ₂ ) ₄ CF ₃ is preferred. .

A fluorous solvent has the advantage of suppressing or preventing side reactions, for example, because the solvent itself has low reactivity. The side reactions include, for example, an oxidation reaction of the solvent, a hydrogen abstraction reaction of the solvent by radicals, and a chlorination reaction.

The aqueous phase may contain components other than the radicals and water, and the organic phase may contain components other than the radicals and the organic solvent.
Examples of the other component include, but are not particularly limited to, the radical generating source, Bronsted acid, Lewis acid, and oxygen (O ₂ ).
Each of these may be used alone or in combination of two or more.
Said other ingredients may be dissolved in the aqueous phase and/or the organic phase, but they do not have to be dissolved.
In addition, one substance may serve as both the Lewis acid and the Bronsted acid. The term "Lewis acid" refers to a substance that acts as a Lewis acid against the above radical generation source.

The source of the radical is not particularly limited, but when the radical is a chlorine dioxide radical, for example, chlorous acid (HClO ₂ ) or a salt thereof may be used. Salts of chlorous acid are not particularly limited, and examples thereof include metal salts. Examples of the metal salt include alkali metal salts, alkaline earth metal salts and rare earth salts.
More specifically, the chlorine dioxide radical generation source is, for example, sodium chlorite (NaClO ₂ ), lithium chlorite (LiClO ₂ ), potassium chlorite (KClO ₂ ), magnesium chlorite (Mg (ClO ₂ ) ₂ ) and calcium chlorite (Ca(ClO ₂ ) ₂ ). Among these, sodium chlorite is preferable from the viewpoint of cost, ease of handling, and the like.

Although the concentration of the radical generation source in the aqueous phase and/or organic phase is not particularly limited, it is, for example, 0.0001 mol/L or more and 1 mol/L or less.

The Lewis acid is not particularly limited, and may be, for example, an organic substance or an inorganic substance.
Examples of the organic substances include ammonium ions and organic acids (eg, carboxylic acids).
The inorganic substance may contain one or both of metal ions and non-metal ions. The metal ions may contain one or both of typical metal ions and transition metal ions.
The inorganic substance includes, for example, alkaline earth metal ions (e.g., Ca ²⁺ ), rare earth ions, Mg ²⁺ , Sc ³⁺ , Li ⁺ , Fe ²⁺ , Fe ³⁺ , Al ³⁺ , silicate ions and It may be at least one selected from the group consisting of borate ions.
The alkaline earth metal ions include, for example, calcium, strontium, barium or radium ions, more specifically Ca ²⁺ , Sr ²⁺ , Ba ²⁺ and Ra ²⁺ .
The term "rare earth" is a general term for a total of 17 elements, including two elements, scandium and yttrium, and 15 elements (lanthanoids) from lanthanum to lutetium. Examples of rare earth ions include trivalent cations.

Further, when the Lewis acid is an ion, the Lewis acid may be a substance having a counter ion of the ion, and the counter ion is, for example, trifluoromethanesulfonate ion (CF ₃ SO ₃ ⁻ ). , trifluoroacetate ion (CF ₃ COO ⁻ ), acetate ion, fluoride ion, chloride ion, bromide ion, iodide ion, sulfate ion, hydrogen sulfate ion, sulfite ion, nitrate ion, nitrite ion, phosphate ion , phosphite ion.

Also, the Lewis acid may be at least one selected from the group consisting of AlCl ₃ , AlMeCl ₂ , AlMe ₂ Cl, BF ₃ , BPh ₃ , BMe ₃ , TiCl ₄ , SiF ₄ and SiCl ₄ . In addition, among these, "Ph" represents a phenyl group, and "Me" represents a methyl group.

The Lewis acidity of the Lewis acid is, for example, 0.4 eV or more, but is not limited thereto. Although the upper limit of the Lewis acidity is not particularly limited, it is, for example, 20 eV or less. The Lewis acidity is described, for example, in Ohkubo, K.; Fukuzumi, S. Chem. Eur. J., 2000, 6, 4532, J. AM. CHEM. SOC. Org. Chem. 2003, 68, 4720-4726.

The Bronsted acid is not particularly limited, and examples thereof include inorganic acids and organic acids. Specific examples include trifluoromethanesulfonic acid, trifluoroacetic acid, acetic acid, hydrofluoric acid, hydrochloric acid, bromo Hydrochloric acid, hydroiodic acid, sulfuric acid, sulfurous acid, nitric acid, nitrous acid, phosphoric acid, phosphorous acid.
The acid dissociation constant pK _a of the Bronsted acid is, for example, 10 or less. Although the lower limit of the pK _a is not particularly limited, it is -10 or more, for example.

The concentration of at least one of the Lewis acid and Bronsted acid in the aqueous phase and/or the organic phase is not particularly limited and can be set as appropriate. is.

For example, oxygen (O ₂ ) can be dissolved in the aqueous and/or organic phase by blowing air or oxygen gas through the aqueous and/or organic phase. At this point, for example, the aqueous phase and/or the organic phase may be saturated with oxygen (O ₂ ).
When the aqueous phase and/or the organic phase contain the oxygen (O ₂ ), for example, film modification (oxidation reaction) can be promoted.

<Radical generation step>
The method may include a radical generation step of generating the radicals, and specifically includes a step of generating the radicals from the radical generation source.

Although the radical generation step is not particularly limited, for example, the radical generation source (eg, chlorous acid or a salt thereof) is dissolved in water and allowed to stand, and the radicals are naturally generated from the radical generation source. can be done. At this time, for example, the presence of at least one of the Lewis acid and the Bronsted acid in the water can promote the generation of the radicals. Alternatively, for example, the radicals can be generated by irradiating an aqueous phase in which the radical generating source is dissolved in water. This light irradiation may be the light irradiation in step 1, that is, the light irradiation may be performed on the radicals while generating the radicals.

For example, a mechanism (mechanism) for generating chlorine dioxide radicals from chlorite ions is presumed as shown in Scheme 1 below. However, Scheme 1 below is an example of a presumed mechanism and does not limit the present invention in any way.
The first (upper) reaction formula in Scheme 1 below shows the disproportionation reaction of chlorite ion (ClO ₂ ⁻ ), and at least one of Lewis acid and Bronsted acid is present in this reaction system. , the equilibrium tends to shift to the right.
The second (middle) reaction formula in Scheme 1 below shows a dimerization reaction, in which hypochlorite ions (ClO ⁻ ) generated in the disproportionation reaction react with chlorite ions to form dioxide. Chlorine (Cl ₂ O ₂ ) is produced. This reaction is thought to proceed more easily as the amount of protons H ⁺ in the water increases, that is, as the water becomes more acidic.
The third (lower) reaction scheme in Scheme 1 below represents radical generation. In this reaction, dichlorine dioxide produced in the dimerization reaction reacts with chlorite ions to produce chlorine dioxide radicals.

In addition, in this method, since the film has a carbon-hydrogen single bond, for example, the reaction proceeds by a mechanism similar to the mechanism (mechanism) of the oxidation reaction of ethane described in JP-A-2017-155017. can be inferred.

<Film>
The film is a film containing an olefin polymer having a melting point and/or a glass transition temperature of 50°C or higher and 300°C or lower.

The olefin-based polymer is not particularly limited, but examples include ethylene-based polymers, propylene-based polymers, butene-based polymers, 4-methyl-1-pentene-based polymers, cyclic olefin-based polymers, ethylene, and propylene. , butene, 4-methyl-1-pentene, hexene, and octene. Further, for example, compounds other than olefins, such as aromatic vinyl compounds such as styrene, and (meth)acrylic acid (esters) may be used as raw materials for the copolymer.
Among these, ethylene-based polymers, propylene-based polymers, butene-based polymers, and 4-methyl-1-pentene-based polymers are preferred, and ethylene-based polymers, propylene-based polymers, and 4-methyl-1-pentene-based polymers are preferred. A polymer is more preferred, and a 4-methyl-1-pentene polymer is particularly preferred, although it depends on the application.

The olefinic polymer may be synthesized by a conventionally known method, or may be a commercially available product.
There are many reports on means for obtaining the olefin-based polymer, and they can be employed without restriction. 2016/136540 and the like, and examples of the method for obtaining the 4-methyl-1-pentene-based polymer include the methods described in International Publication No. 2006/054613 and the like.

Commercially available products of the olefin polymer include HI-ZEX, HI-ZEX MILLION, MIPELON, PRIME POLYPRO, and TPX (all registered trademarks), which are commercially available from Mitsui Chemicals Group.

A polymer having a melting point and/or a glass transition temperature of 50 to 300° C. may be used as the olefin polymer. The melting points and glass transition temperatures mentioned above are those measured by the following method or an equivalent method using the following differential scanning calorimeter (DSC apparatus). Other differential scanning calorimeters may be used as long as they are confirmed to give results equivalent to those of the apparatus described below.

Using an EXSTAR DSC6220 differential scanning calorimeter manufactured by Hitachi High-Tech Science Co., Ltd., about 5.0 mg of a sample was heated from 30 ° C. to 320 ° C. at a heating rate of 10 ° C./min in a nitrogen atmosphere. The temperature is maintained for 10 minutes (however, when using a polymer that decomposes in the temperature range of 250° C. or higher and 320° C. or lower, the temperature may be appropriately adjusted to a lower temperature as is customary). Furthermore, after cooling to 30 ° C. at a temperature decrease rate of 10 ° C./min and maintaining that temperature for 5 minutes, the temperature is raised to 320 ° C. at a temperature increase rate of 10 ° C./min (however, it decomposes in the temperature range of 250 to 320 When a polymer is used, the upper limit temperature may be appropriately adjusted to a low value in the usual manner.). The endothermic peak observed during the second temperature rise is defined as the melting peak, and the temperature at which the melting peak appears is determined as the melting point (Tm). When the melting peaks are multimodal, the temperature at which the highest melting peak appears is taken as the melting point.
Further, the glass transition temperature (Tg) is sensed in the form that the DSC curve bends due to the change in the specific heat during the second temperature rise and the baseline shifts in parallel. The temperature at the intersection of the tangent line of the baseline at a temperature lower than the bend and the tangent line of the point where the inclination is maximum at the bend is defined as the glass transition temperature (Tg).

The intrinsic viscosity [η] of the olefin polymer at 135° C. in decalin is preferably 0.5 to 20 dl/g, more preferably 0.8 to 18 dl/g, and particularly preferably 1 to 15 dl/g. be.
When the intrinsic viscosity of the olefin polymer is within the above range, the moldability and strength are well balanced.

The melt flow rate of the olefin polymer measured according to the ASTM 1238 standard varies depending on the melting point of the resin used, as will be described later, but the preferred range of the melt flow rate is 0.1 to 200 g/ 10 minutes. A preferred lower limit is 1 g/10 minutes, more preferably 3 g/10 minutes, and even more preferably 5 g/10 minutes. On the other hand, the upper limit is preferably 150 g/10 minutes, more preferably 130 g/10 minutes.
Preferred measurement conditions for the melt flow rate (ASTM1238 standard) are as follows.
190° C., 2.16 kg load for ethylene polymers, 230° C., 2.16 kg load for propylene polymers, 260° C., 5 kg load for 4-methyl-1-pentene polymers , 260° C. and 2.16 kg load in the case of a cyclic olefin polymer.

The film can be produced by a known method, and specific examples include extrusion molding (e.g., T-die molding), inflation molding, and cast molding (including cases where spin coating is used in combination). can be mentioned as
Further, the film may be a film obtained by forming a film by any of these methods and then stretching the film. By performing this stretching, it is possible to increase the degree of crystallinity and transparency in visible light, and to make the film porous. In the case of porosity, the film containing the dispersed fine particles may be stretched.

The film contains other polymers, antioxidants, heat stabilizers, light stabilizers, various stabilizers such as weather stabilizers, antistatic agents, hydrophilic agents, and water repellents, as long as the objects of the present invention are not impaired. , nucleating agents, slip agents, anti-blocking agents, anti-fogging agents, lubricants, dyes, pigments, flame retardants, and other additives.

The thickness of the film is preferably 1 to 1000 μm, more preferably 5 to 500 μm, still more preferably 10 to 300 μm.
When the thickness of the film is within the above range, functions such as surface properties can be easily imparted while maintaining mechanical properties such as strength of the film. Although depending on the wavelength of the light used and the light absorption properties of the olefin polymer, if the film is too thin, it may be difficult to make a fine design such as modifying mainly a part of the surface.

[Modified film]
The film may be introduced with a functional group containing an atom (α) contained in the radical, or may be introduced with a functional group containing group 15 or group 16 atoms derived from oxygen in the air. be. At this time, atoms (β) contained in the radicals may also be introduced into the film.
According to this method, it is thought that the atoms (β) are also introduced into the film in this way, so that the effect of the atoms (β) may also be expected in the modified film.

It has been reported that introduction of Group 17 atoms is suppressed when modifying low-molecular-weight hydrocarbon compounds such as alkanes using the radicals. In some cases, it can be introduced into the film together with atoms. This is due to the fact that the existence density of carbon-hydrogen bonds in the film tends to be higher than in the case of modifying low-molecular substances such as methane and ethane, and the interaction between the film and radicals. The present inventors believe that one reason for this is that radicals may be stabilized. However, this speculation does not limit the present invention.

As the functional group containing the atom (α), when the radical contains oxygen, for example, a hydroxy group, a carboxyl group, an aldehyde group, a carbonyl group, an ether bond, an ester bond, -C(=O)OOH, - OO- is included.
When atoms (β) are introduced into the film, the ratio between the total amount of atoms (α) [Cα] and the total amount of atoms (β) [Cβ] introduced into the film [Cα]/[Cβ] The lower limit of is preferably greater than zero, more preferably 0.01, more preferably 0.1, particularly preferably 0.5, and the upper limit is preferably 5000, more preferably 100, more preferably is 20.
The above [Cα] and [Cβ] values are values specified by the XPS method. The measurement is carried out by a conventional method using the product name AXIS-Nova (manufactured by KRATOS).

According to this method, it is expected that the surface of the film to be modified can be mainly modified. Therefore, even if the olefinic polymer molecules that make up the film are cut or crosslinked during modification, it will mainly remain on the surface of the film, and the impact on the performance inside the film, such as the strength of the film, will be minimal. This is advantageous in terms of maintaining the strength of the film.
The surface refers to a region whose depth from the surface of the film is 1/10 or less, more preferably 1/20 or less of the thickness. The depth of this denatured portion can be confirmed by, for example, the XPS method.

According to the method, the entire surface of the film can be modified, only a portion of the surface can be modified, or only a portion of the surface can be modified.
Since the method proceeds via light, it is expected that it will be able to modify primarily the location where the light strikes.
In addition, if only one surface of the film is irradiated with light, it is possible to modify only a specific portion by controlling the portion exposed to the light using a modified film modified only on the one surface or a photomask. It is also expected that the ratio of the unmodified portion can be freely controlled.

For example, the area of the denatured portion of the denatured film may be appropriately selected according to the desired application of the denatured film, such as a usage pattern in which the denatured film is attached to a window or the like. As 100%, preferred lower limits are in the order of 1%, 5%, 10%, 20%, 30% and 50%, and preferred upper limits are 100%, more preferably 90%. Denatured regions can be identified by known methods such as the XPS method.
It is considered that the modification progresses with radicals of group 17 elements generated by exposure to light in the presence of the radicals as starting points. Therefore, it is considered that the modification occurs at the portion where the radical contacts the film to be modified. For example, in the method (I), when the radicals and the film are irradiated with light, the irradiated area of the film to be modified and the modified area may be considered to be substantially equivalent.
Although the peripheral portion irradiated with light and the deep layer portion of the pore where the light does not reach may be denatured, the ratio is considered to be small.

The modified film obtained by this method may be used as it is, or the functional groups introduced as described above may be reacted with other components to enhance the function or change the properties. good. For example, by using the above functional group as a scaffold and reacting it with a silicone component having various structures, extremely high releasability can be imparted.

It is considered that the modified film can be preferably applied to various uses.
When the modified film is a porous film, it is considered to be suitable for various separator applications such as batteries, filter applications, release films, and the like.
The release film may be, for example, a release film having a laminated structure in which an olefin polymer film such as TPX (registered trademark) is laminated with paper, a polyester film, or the like. In this case, when the modified film obtained by this method is used only on one side, and the modified side is laminated with paper, polyester film, etc., the adhesion performance with the paper, polyester film, etc. is improved, and other The surface can be expected to be an excellent laminated release film that can exhibit release performance.

Further, even when a film having a complicated surface shape such as a porous film is used as the film, according to the present method, it can be expected that even the smallest details can be modified. This is because the modification by this method is considered to be a modification originating from a radical having a simple structure such as a chlorine radical, as the presumed mechanism described above, and high mobility can be expected. It is believed that such characteristics can be applied not only to film surfaces but also to fine surfaces of moldings such as injection moldings.

In the modified film, the molecular weight of the olefinic polymer is less reduced due to the modification, so that the modified film can be easily obtained with less reduction in strength and excellent durability in the above applications. In addition, since a relatively large number of functional groups can be introduced by modification, it can be expected that the deterioration rate of the performance imparted by the modification over time will be small.

Another promising application is the use of photomasks in the shape of letters and pictures to denature only certain areas when exposed to light, and to attach pigments to the denatured areas as a display film. be done.

Examples of the present invention will be described below. However, the present invention is not limited to the following examples.

[Example 1]
Put 10 g of sodium chlorite (manufactured by Sigma-Aldrich) and 100 mL of ultrapure water in a plastic container, dissolve the sodium chlorite in the ultrapure water, and then add 35 to 37% hydrochloric acid aqueous solution (Fujifilm Wako Pure Chemical ( (manufactured by Co., Ltd.) was added to prepare a mixed solution. The presence of chlorine dioxide radicals in the mixture under these conditions was separately confirmed by the ESR method. This mixture was placed in a shallow vat of approximately 22 cm x 16 cm x 1.5 cm high and placed on a rack. Next, a TPX film of about 28 cm × 20 cm (poly 4-methyl-1-pentene, manufactured by Mitsui Chemicals, Inc., DX231, 50 μm thick, melting point: 231 ° C., melt flow rate (ASTM 1238 standard, 260 ° C., 5 kg load): 100 g/10 minutes) was placed on the vat so as not to touch the mixed solution (the state at this time is shown in FIG. 1). The film was irradiated from above with Hololite Kaku DC12V manufactured by Pi Photonics Co., Ltd. with light having a wavelength of 365 nm for 10 minutes at 50 to 70 mW/cm ² . Thereafter, using a washing bottle, ultrapure water was poured over the entire surface of the film to wash it, followed by drying under reduced pressure to obtain a modified TPX film.

<Hydrophilic evaluation of TPX film>
Eight EnerDyne pens (dyne levels: 30, 32, 35, 38, 41, 30, 32, 35, 38, 41, 30, 32, 38, 41, 30, 32, 41, 41, 41, 41, 41, 41, 41, 41, 41, 41, 41, 41, 41, 41, 41, 41, 41, 41, 41, 41, 41, 41, 41, 41, 41, 41, 41, 41, 41, 41, 41, 41, 41, 41, 31, 31, 31, 34, 34, respectively) were applied to the untreated TPX film and the modified TPX film, respectively. 44, 48 and 56), a line of about 1 cm was drawn to visually confirm the wettability of the ink. Table 1 shows the results. FIG. 2 shows the state of the film at this time. The numbers above the numbers in FIG. 2 indicate the state of the oxidized TPX film, and the numbers below the numbers indicate the state of the untreated TPX film.

Claims (9)

Number of atoms (α): number of atoms (β) = 1:1 comprising step 1 of irradiating in the presence of radicals in a ratio of ~4:1;
A method for producing a modified film by partially or entirely modifying an olefin polymer film having a melting point and/or a glass transition temperature of 50° C. or more and 300° C. or less, comprising:
The atom (α) is an oxygen atom, and the atom (β) is an atom selected from chlorine, bromine and iodine,
A method for producing a modified film . 2. The method for producing a modified film according to claim 1, wherein said step 1 is a step of modifying said film by irradiating said radicals with light in the presence of said radicals and said film. 3. The method for producing a modified film according to claim 1, wherein said step 1 is a step of modifying said film by irradiating said radicals and said film with light in the presence of said radicals and said film. 4. The method for producing a modified film according to any one of claims 1 to 3, wherein the step 1 is a step performed without bringing the film into contact with the aqueous phase and/or organic phase containing the radicals. The method for producing a modified film according to any one of claims 1 to 4, wherein the modified film has a thickness of 1 to 1000 µm. The method for producing a modified film according to any one of claims 1 to 5 , wherein the radical is a chlorine dioxide radical. The method for producing a modified film according to any one of claims 1 to 6 , wherein the olefin polymer is a 4-methyl-1-pentene polymer. The method for producing a modified film according to any one of claims 1 to 7 , wherein the modified film is a porous film. The method for producing a modified film according to any one of claims 1 to 8 , wherein the modified film is a release film.

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