JPH09239889A - Basic composite film having good uv cut-off and see-through properties, practical composite film using the same, and manufacture of them - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a thin, soft film which cuts off near UV rays well, and is bloomingless. SOLUTION: A basic composite film consists of an UV cut-off layer and a migration obstructing layer which are laminated on both side of the UV cut-off layer. The UV cut-off layer contains an UV absorbing agent which absorbs near ultraviolet rays well, and the amount of the agent corresponds at least to the solubility at room temperature. The migration obstructing layers are formed from an oxygen-containing resin, and at least one of them is laminated by coextrusion with the UV cut-off layer. Moreover, in a practical composite film, on one side of the basic composite film, for example, polyolefin inner skin layer and/or on the other side, for example, a nylon outer skin layer are laminated. The adjacent two layers of one of the two composite films are coextruded or lamination-bonded with an adhesive polymer placed between them. Therefore, the following is made possible: ultraviolet transmittance 20% or less, visible light transmittance 80% or more, no blooming of UV absorbing agent, no deterioration of packaged contents after a long period, and durable transparency and oxygen barrier properties.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is a thin film that exhibits both transparency (high transmittance of visible light) and high ultraviolet blocking property (ultraviolet absorptivity), which has hitherto been difficult to realize in the near ultraviolet region. Even if it is a layered body such as a film, a basic composite film that does not cause blooming (also known as "bloom"; powder blowing on the film surface) of the compounded organic ultraviolet absorber, a practical composite film using the basic composite film, for example The present invention relates to a method for producing a laminated film in which one or more laminating steps constituting the steps for producing a packaging material film and a basic composite film are coextrusion lamination.

[0002]

2. Description of the Related Art A "transparent package for contents" in which food, cosmetics, medical products or the like to be packaged are packaged using a bag or the like which is transparent to visible light, that is, made of a film having high transparency. In ", the packaged object may be subjected to undesired effects such as deterioration, discoloration and / or deterioration due to ultraviolet rays passing through the film. This alteration, discoloration and /
Alternatively, measures to effectively prevent or suppress deterioration etc. have not been established yet.

Although the purposes of use thereof are substantially the same, the means having a measure to prevent or suppress the action of ultraviolet rays having a different purpose has already been implemented. For example, a sheet in which ultraviolet rays incident from a daylighting facility such as a window of a building is attached to a window glass or the like for the purpose of preventing sunburn or the like inside the building is already widely used.

However, this measure cannot completely eliminate blooming of the thin-layer packaging material itself, and completely prevents discoloration, deterioration or deterioration of the packaged object such as the food contained therein. Is not enough to do so. That is, in order to highly prevent discoloration of foods, etc., even in an extremely small amount, particularly in the near ultraviolet region, particularly in the wavelength region of 320 to 390.
It is necessary to select an organic UV absorber capable of effectively absorbing a ray of nm and to add it at a concentration equal to or higher than the room temperature solubility in the matrix resin. Even if this UV blocking measure is carried out on a sheet which is a thick material to be stuck to a window glass, there is no fear that the organic UV absorber causes blooming. That is, if the amount of the organic ultraviolet absorber added to a thin material such as a film reaches a concentration equal to or higher than room temperature solubility, the concentration of the sheet is much lower.

However, when the above-mentioned organic UV absorber is added to a film having a thickness of about 100 μm or less in an amount required to prevent even slight discoloration of foods, the concentration inevitably exceeds the room temperature solubility. As a result, the organic ultraviolet absorber causes blooming in most cases. Since this blooming phenomenon naturally lowers the transparency and see-through property of the film, it causes a situation in which the added organic ultraviolet absorber cannot exert its effect. It is necessary to prevent or suppress it beyond the scope of the above.

[0006]

DISCLOSURE OF THE INVENTION The object of the present invention is to mix ultraviolet rays in the near-ultraviolet region, particularly in the wavelength region of 320 to 390 nm by blending an organic ultraviolet absorber in a resin constituting a film at a concentration of room temperature solubility or higher. While it is a film that can be absorbed and removed at a high rate and does not absorb light in the visible region as much as possible, an effective blocking measure or suppressing measure for blocking so as not to substantially cause the above blooming is searched for, and further To provide products that embody

[0007]

Means for Solving the Problems The present inventor has sought various measures for solving the above problems. As a result, in order to develop the ultraviolet blocking film which is the object of the present invention, it is not possible to bring about an effective solution simply by diverting the idea of the ultraviolet blocking sheet for pasting window glass which seems to be similar at first glance. I reached the conclusion.

In other words, it is necessary to solve the additional problem which has not been a problem in the ultraviolet ray shielding sheet for attaching a window glass. The additional problems are as follows: P1: Request to effectively remove the near-ultraviolet region to prevent discoloration and deterioration of foods; P2: In thin resin layer such as film In addition, there is no need to mix organic UV absorbers at concentrations beyond the norm of room temperature solubility or higher; P3: Effective blooming of organic UV absorbers blended at concentrations outside the common sense shown in P2 above. P4: A request to prevent the strong blooming tendency of organic UV absorbers having excellent UV absorption in the near-ultraviolet region.

The interrelationship of the above P1 to P4 makes the solution more difficult. Therefore, it is necessary to search for a solution that solves them all together. The solution completed by the inventor is as specified in the following item (1),
It is a measure to prevent blooming of an organic UV absorber from a resin film (plastic film) that contains an organic UV absorber that has excellent absorption in the near-UV region but exhibits a strong blooming tendency at a concentration equal to or higher than its room temperature solubility. This is a measure to ensure transparency.

Moreover, in order to produce the basic composite film and the practical composite film of the present invention, the following items (2) and (3)
The method for producing the basic composite film and the practical composite film defined in Section 1 is important. The present invention includes the following items (1) and (2)
The desired effect is achieved by the connection with or the connection between item (1) and item (3). This is explained below.

The present invention comprises item (1) a basic composite film, a practical composite film, and an item, which are constituted by combining the following requirements:
(2) and (3) relates to a method for producing a practical composite film.
The layer constitution of the composite film of the present invention, its details, etc. are shown in Table 1 or Table 2: (1) An organic UV absorber is blended with a thermoplastic polymer at a concentration equal to or higher than its room temperature solubility. A laminated film in which a migration blocking layer of an organic UV absorber made of an oxygen atom-containing thermoplastic resin is laminated on both sides of the UV blocking layer, wherein at least one of the migration blocking layers is coextrusion laminated to the UV blocking layer. Basic composite film with excellent UV blocking and transparency.

In the above basic composite film and practical composite film, the thermoplastic resin or the like has at least one selected from polyolefin resins, ionomer resins, adhesive polyolefin polymers or olefinic thermoplastic elastomers as a main component. be able to. These thermoplastic resins and the like are not limited to homopolymers, copolymers of two or more α-olefins, compositions of two or more homopolymers,
It may be a composition of a homopolymer and a copolymer or a composition of two or more kinds of copolymers.

The oxygen atom-containing thermoplastic resin forming the migration inhibiting layer in the above basic composite film and practical composite film is a polyamide resin (nylon; NY), a polycarbonate resin (PC), or a thermoplastic polyester resin (P
ET or PBT, etc.), ethylene-vinyl alcohol copolymer resin (EVOH) or polyalkyl (meth) acrylate (PMMA etc.) resin as a main component, a single thermoplastic resin, either of them as a main component, It may be a resin composition in a form in which one or more other subcomponents are added. The above-mentioned oxygen atom-containing thermoplastic resin may be used in the form of a composition formed of a combination of two or more kinds, for example, 6-nylon (or 6,6-nylon) and an ethylene-vinyl alcohol copolymer. A composition with a resin can be mentioned.

In the above basic composite film and practical composite film, the migration inhibiting layer has an average layer thickness of 3 to 70 μm,
It is preferably 5 to 40 μm.
Since this migration prevention layer plays a large role in imparting hardness (rigidity) to the basic composite film and the practical composite film, it is preferable that the resin itself has excellent rigidity.

The organic ultraviolet absorber contained in the above-mentioned basic composite film and practical composite film must be an organic compound that exhibits strong absorption in the near ultraviolet region and has excellent transmission in the visible light region. . The reason is as follows. That is, when it is attempted to effectively absorb the ultraviolet rays in this region for the purpose of effectively preventing the ultraviolet rays in the near ultraviolet region from exhibiting particularly remarkable photochemical reactivity, this region becomes continuous in the short wavelength region of visible light. Due to this, visible light in the short wavelength region is also removed together. As a result, it is extremely important to avoid the situation where the film is colored.

Next, in the above-mentioned basic composite film and practical composite film, the organic ultraviolet absorber contained is 0.1 g / m ² or more (the film area), preferably 0.2 to 1.5 g. / M ² (area of the film).

In the above-mentioned basic composite film and practical composite film, the organic ultraviolet absorber contained is in the wavelength range 32.
It absorbs and removes ultraviolet rays belonging to 0 to 390 nm to a transmittance of 20% or less, and transmits visible rays belonging to a wavelength range of 400 to 800 nm of 70% or more, preferably 80% or more,
More preferably, it does not absorb up to a level of 90% or more. That is, since the organic UV absorber highly removes ultraviolet rays, particularly near-ultraviolet rays as a result of removing visible rays to a considerable extent, it causes the coloring of the packaging material film, which should be especially avoided. Is. Therefore, it is preferable that the basic composite film and the practical composite film of the present invention are excellent in the removal rate of ultraviolet rays (show a low transmittance) and also excellent in the visibility of visible light rays (show a high transmittance).

Practical composite films embodying the various properties described above, for example packaging films, are as follows: on the surface of any of the migration inhibiting layers that make up the basic composite film. Whether the inner layer is laminated on the surface facing the object to be packaged, or the surface of any one of the migration inhibiting layers constituting the basic composite film, and the outer layer is laminated on the surface opposite to the object to be packaged, Or, a practical composite film in which an inner skin layer is laminated on the surface of the migration prevention layer constituting the basic composite film and facing the object to be packaged and an outer skin layer is laminated on the surface opposite to the object to be packaged, for example , Films for packaging materials.

The preferred embodiments for producing the basic composite film or the practical composite film of the present invention by the coextrusion laminating method are as follows: The adhesive thermoplastic resin is an adhesive low density polyethylene resin, and the organic ultraviolet light is used. A benzotriazole-based compound as an absorber is kneaded and mixed by a melt-kneading means to prepare a composition for an ultraviolet blocking layer containing an organic ultraviolet absorber at a concentration of room temperature solubility or higher.

Three extruders were used, and the No. 1 extruder was charged with polyamide resin as an example of oxygen atom-containing resin for melt-kneading, and the outer side of the migration prevention layer located on the outer skin layer side. A molding composition for the migration prevention layer is prepared. The No. 2 extruder is charged with the above molding composition for the ultraviolet blocking layer and melt-kneaded. An ethylene-vinyl alcohol copolymer resin as an oxygen atom-containing resin, which is another unusual example, is charged into the No. 3 extruder and melt-kneaded to prepare a molding composition for the inner migration inhibiting layer.

Next, the resin streams are supplied from the respective extruders to a common multi-layer die, and the resin streams are combined through the dies so that the outer migration blocking layer, the ultraviolet blocking layer and the inner migration blocking layer are laminated. After laminating, the multilayer resin flow is guided to an annular die for inflation molding to obtain a basic composite film. An example of the layer structure of the obtained basic composite film is 6-NY // (organic UV absorber / modified low density P
E) // EVOH.

In a preferred embodiment of the above practical composite film and the film for packaging material which is an important use thereof, a benzotriazole compound as an organic UV absorber is added to 100 parts by weight of an adhesive polyolefin resin at a concentration of room temperature solubility or higher. On one side of the UV blocking layer containing 2 parts by weight or more, for the migration blocking layer having an average layer thickness of 5 to 70 μm containing a polyamide resin as an oxygen atom-containing resin as a main component is laminated on one side, and the UV blocking layer is separately provided on the opposite side. As a different oxygen atom-containing resin, a migration blocking layer having an average layer thickness of 3 to 30 μm containing ethylene-vinyl alcohol copolymer resin as a main component is laminated, and a laminating adhesive layer is further formed on the surface of any of the migration blocking layers. A mode in which a polyolefin resin layer is laminated and laminated as an inner layer through the layer can be mentioned.

Another preferred embodiment of the above-mentioned practical composite film, for example, a packaging material film, is a thermoplastic polymer 1
A migration blocking layer containing a polyamide resin as a main component as an oxygen atom-containing resin is provided on one side of an ultraviolet blocking layer containing 00 parts by weight of a benzotriazole compound as an organic ultraviolet absorber at a concentration of at least room temperature solubility and 2 parts by weight or more. An average layer thickness of 5 to 70 μm is laminated, and on the other side, a migration inhibiting layer containing an ethylene-vinyl alcohol copolymer resin as a main component is formed as another oxygen atom-containing resin layer.
In addition to being laminated at 30 μm, at least one of the migration prevention layers located on both sides of the ultraviolet blocking layer is co-extruded on the ultraviolet blocking layer via an adhesive polymer layer.

In addition, when the composite film of the present invention is a practical composite film, the surface of any one of the migration-preventing layers described above is coated with a resin film of a type adaptable to each application, as an inner skin layer or outer skin layer. And so on. Examples of the laminating method include a laminating adhesion method or a co-extrusion method through an adhesive polymer layer, and the resin film mainly contains a resin selected from polypropylene resin, polyamide resin and thermoplastic polyester resin. A film, preferably a stretched film is used, and can be exemplified as the various embodiments described below: ◆ When a resin film is laminated as a skin layer, it is a laminating laminating method or adhesiveness on the surface of the migration inhibiting layer. It may be laminated by any of the coextrusion methods via a polymer layer, but when a stretched film suitable as an outer skin layer is laminated, the outer skin layer may be laminated on the surface of the migration inhibiting layer. ◆ If the resin film is laminated as the inner layer, it may be laminated on the surface of the migration prevention layer. May be laminated by any of coextrusion methods through an adhesive polymer layer; ◆ When a resin film is laminated as an outer skin layer and an inner skin layer, the outer skin layer is the surface of any migration prevention layer. Is laminated by a laminating lamination method or a coextrusion method through an adhesive polymer layer, and the endothelial layer is laminated on the surface of the migration preventing layer on the opposite side by a laminating lamination method or a coextrusion method through an adhesive polymer layer. It can be laminated. Also in this case, the above-mentioned restrictions are imposed when the outer skin layer is a stretched film.

In the above basic composite film or practical composite film, for example, a film for packaging material, a benzotriazole compound is preferably used as an organic ultraviolet absorber in the basic composite film in an amount of 0.1 g / m ² or more, preferably 0. .
It is contained at ² to 1.5 g / m ² .

Further, the aspect of the method for producing the above basic composite film or a practical composite film which is an application thereof, for example, a film for packaging material is exemplified in the following items (2) and (3). (2) As an example of a method for producing the basic composite film, a matrix resin containing an adhesive polymer (resin) as a main component absorbs and removes 80% or more of light in the near ultraviolet region as an organic ultraviolet absorber and An organic compound which transmits 70% or more, preferably 80% or more, more preferably 90% or more of light, preferably a UV blocking layer by melt-kneading a mixture containing a benzotriazole compound at a concentration of room temperature solubility or more. Of the three extruders, and then extruding an oxygen atom-containing resin, such as a polyamide resin, from the No. 1 extruder of the three extruders to form a resin flow for the migration prevention layer, and from the No. 2 extruder. The composition for the ultraviolet blocking layer is extruded to form a resin stream for the ultraviolet blocking layer, and an oxygen atom-containing resin such as ethylene-vinyl alcohol is discharged from the No. 3 extruder. The resin copolymer resin is extruded to form a resin flow for the migration prevention layer, and then the resin flow from each extruder is supplied to a common die to prevent the migration prevention layer // UV protection layer // migration A method of producing a laminated film by inflation molding a multilayer resin flow obtained by coextruding a resin flow so as to form a layer structure of a blocking layer, or by performing multilayer T die molding of the above multilayer resin flow can be mentioned. . (3) As another example of the manufacturing method of the basic composite film, when the ultraviolet blocking layer mainly comprises a thermoplastic polymer , 80% of the light in the near ultraviolet region is added as an organic ultraviolet absorber to this.
Absorbing and removing more than 70% of visible light,
An organic compound which transmits preferably 80% or more, more preferably 90% or more, preferably the method described in the above item (2) except that the benzotriazole compound is contained at a concentration of room temperature solubility or more. In addition to the method described in the above item (2), in addition to the method in which the ultraviolet blocking layer contains a benzotriazole-based compound as an organic ultraviolet absorber in a polyolefin resin at a concentration of room temperature solubility or higher. , Using an additional one extruder as the No. 4 extruder, between the resin flow from the No. 1 extruder and the resin flow from the No. 2 extruder (“between 1-2”) and the No. 2 extruder. Between the resin flow from the extruder and the resin flow from the No. 3 extruder (“between 2-3”), the adhesive polymer stream is supplied from the No. 4 extruder, or by adding two additional units. Using the extruders as No. 4 extruder and No. 5 extruder, respectively, Supplying an adhesive polymer flow from between ( "1-2 between") in the fourth extruder or fifth extruder with the resin flow from the resin flow and 2nd extruder from the extruder, while the 2
Between the resin flow from the No. 3 extruder and the resin flow from the No. 3 extruder
No. 4 extruder or No. 5 extruder (“1-2-3”)
Between the extruders that supplied the adhesive polymer stream to the `` between '', the resin flow from each extruder is supplied to the common die in the form of supplying the adhesive polymer stream from a different extruder // Inflation of a multilayer resin flow laminated by co-extruding a resin flow and an adhesive polymer flow so that the adhesive polymer layer /// ultraviolet blocking layer // adhesive polymer layer // migration prevention layer has a layer structure There may be mentioned a method for producing a basic composite film having an interlayer adhesive layer added thereto by molding or multilayer T-die molding of the multilayer resin flow.

[0027]

BEST MODE FOR CARRYING OUT THE INVENTION

<1. Basic composite film> The basic composite film of the present invention is one in which both surfaces of the ultraviolet blocking layer are covered with one or more migration blocking layers, and at least one migration block in the migration blocking layer. The blocking layer is coated on the UV blocking layer by coextrusion lamination. If necessary, an adhesive polymer layer or an adhesive layer in the laminating method may be interposed between the ultraviolet blocking layer and the migration blocking layer.

The basic composite film of the present invention may be used by itself, or may be used as a part of a large number of layers constituting a practical composite film which is a multi-layer in the form in which it is used. May be done. In the latter case, even if the production method of the practical composite film to be used is to produce it by coextrusion as a whole, a part of it is produced by coextrusion and the rest is produced by another method such as a laminating method. It may be manufactured.

Each layer constituting the basic composite film and the practical composite film of the present invention will be described below: <1.1. UV Blocking Layer> The organic UV absorber is a thermoplastic resin or a thermoplastic elastomer, preferably a polyolefin resin. Or a matrix formed from a polyolefin-based thermoplastic elastomer (the "thermoplastic resin" and "thermoplastic elastomer" may be collectively referred to as "thermoplastic resin") uniformly dispersed in the thermoplastic resin, etc. In this state, the UV blocking layer containing the organic UV absorbing agent at a concentration equal to or higher than the room temperature solubility is used as a base layer, and a transfer blocking layer (abbreviated as “migration blocking layer”) of the organic UV absorbent described below is formed on both surfaces of the UV blocking layer. It is necessary that at least one of the transfer blocking layers is laminated and coextruded on the ultraviolet blocking layer.

Here, if the concentration of the blended organic ultraviolet absorber is "concentration at or above room temperature solubility", the blended organic ultraviolet absorber always causes blooming (bloom) at room temperature. Although the value varies to some extent depending on the type of matrix resin and the type of organic UV absorber to be blended, it is a concentration that can never be adopted for ordinary compounding purposes (it is unrealistic to adopt). .

This ultraviolet blocking layer is not limited to a single layer, but may be a laminate (composite layer) of two or more layers. However, it is necessary that the thickness range of the laminated body is the same as the thickness range imposed on a single layer. Further, the thickness of each of two or more layers forming the laminated body may be different from each other.

The optimum layer structure for the basic composite film of the present invention is one in which a migration blocking layer is directly bonded to the surface of the ultraviolet blocking layer. That is, as the basic composite film, a laminate in which the ultraviolet blocking layer is composed of a matrix resin having sufficient adhesiveness to the migration blocking layer is optimal.

<1.2. Migration Blocking Layer> The migration blocking layer is a transparent layer laminated on both sides of the ultraviolet blocking layer in the basic composite film of the present invention, and its role is basically already described above. As described above, the organic UV absorber contained in the UV blocking layer at a high concentration which should naturally be deposited should not be deposited (blooming) outside the migration blocking layer.

The migration blocking layer has a different function from the basic composite film formed by laminating with the ultraviolet blocking layer and a practical composite film obtained from the basic composite film, which has sufficient properties for packaging materials such as oxygen gas. Bending properties such as barrier properties, rigidity, tensile properties, tear resistance properties, heat resistance (heat distortion resistance), etc. are to be imparted as necessary.

The migration blocking layer is laminated directly on the surface of the ultraviolet blocking layer, or indirectly laminated via an adhesive polymer layer. Whether or not to interpose the adhesive polymer layer is determined by whether or not the combination of the base resin of the migration blocking layer and the resin forming the matrix of the ultraviolet blocking layer or the thermoplastic elastomer and / or any laminating method is applied. It is enough to do it according to the condition.

At least one of the two migration-preventing layers laminated on both sides of the ultraviolet blocking layer needs to be a laminate formed by coextrusion molding with the ultraviolet blocking layer. The lamination by the coextrusion molding method is not limited to the case where the ultraviolet blocking layer and the migration blocking layer are directly bonded, and may be performed in a mode in which an adhesive polymer layer is interposed between the two layers, if necessary. . The case where the interposition is necessary is a case where the adhesiveness for directly joining the two layers is lacking and the two resins are laminated by coextrusion molding.

Alternatively, one of the laminations between the "ultraviolet blocking layer" and the "migration inhibiting layer" described above is sometimes performed with the interposition of a laminating adhesive. However, an adhesive polymer layer described later does not intervene in this laminate lamination.

Of course, by interposing the adhesive polymer layer, even if both the layers to be laminated have a certain affinity with the other layer even by themselves, the interposition of the adhesive polymer layer makes a marked difference between the two layers. In some cases, a strong bond can be achieved.

The above migration blocking layers laminated on both sides of the ultraviolet blocking layer are not limited to a single layer on either side, and may be a laminate (composite layer) of two or more. However, it is necessary that the layer thickness range of the entire laminate is the same as the layer thickness range imposed on a single layer. However, the layer thicknesses of the layers forming the laminate may be different from each other.

<1.2.1. Layer Thickness of Migration Blocking Layer> Among the layers constituting the basic composite film of the present invention, if the layer thickness of the migration blocking layer is set as follows, a problem will occur in most cases. There is no. That is, in the laminated film of the present invention containing at least the basic composite film of the present invention, the average layer thickness of one side of the migration inhibiting layer is 3 to 70 μm, and the preferable average layer thickness is 5
It is preferably composed of -40 μm. Of course, the layer thicknesses of the migration blocking layers on both sides may be different from each other, but in that case, it is natural that both migration blocking layers on both sides are within the above-mentioned layer thickness range.

The significance that the layer thickness of the migration blocking layer is set as described above is, as already described in “<1.2. Migration blocking layer>”, primarily, the organic system in the ultraviolet blocking layer is used. It is to prevent the ultraviolet absorber from tending to deposit outside the migration prevention layer. Therefore, if the layer is too thin, the blocking function may be insufficient, and in addition, the oxygen gas barrier property may be insufficient and the hardness (rigidity) of the formed basic composite film may be insufficient.

<1.3. Adhesive Polymer Layer> In the basic composite film of the present invention (itself, a practical composite film based on it and a film for packaging material which is a strong use thereof), the adhesive polymer layer is particularly UV-ray. An example is an embodiment used as an intervening layer for laminating both layers by coextrusion when adhesiveness cannot be expected in terms of material between the barrier layer and the migration inhibiting layer. For the lamination between the outer migration-inhibiting layer and the outer skin layer and / or between the inner migration-inhibiting layer and the inner skin layer, lamination using an adhesive polymer or a laminating adhesive is carried out depending on the case. .

In view of the above-mentioned role of the adhesive polymer, the materials of the adhesive polymer layer interposed on both sides of the ultraviolet ray blocking layer may be left and right different from each other as required. <2. Material of each layer of basic composite film> In the present specification, the term "being a main component" means that another type of thermoplastic resin and / or elastomer is contained in an amount within a range in which the properties of the component can be substantially preserved. And the like can be contained together. Further, the “thermoplastic resin” in the present invention is not limited to a crystalline resin, but is recognized as “thermoplastic resin” in the resin molding processing industry, and an amorphous polymer or a low crystalline polymer which is distributed and molded. Also includes.

<2.1. Material of UV Blocking Layer> The thermoplastic resin which is the matrix of the UV blocking layer of the present invention, particularly the (α-) olefin thermoplastic resin (polyolefin resin) has 2 to 10 carbon atoms. , Preferably 2 to 6 α
-Not only an olefin homopolymer but also a combination of two or more crystalline copolymers selected from the α-olefins, a combination of two or more homopolymers, and two or more crystalline copolymers Combination of one or more homopolymers and one or more crystalline copolymers, resins selected from thermoplastic elastomers containing these as resin components, or modified polymers thereof, particularly adhesiveness The imparting polymer is the main component.

Preferred as these polyolefin resins, olefinic thermoplastic elastomers or modified polymers thereof are those which have sufficient adhesiveness to the organic ultraviolet absorber-containing migration inhibiting layer and are, for example, anhydrous. Maleic acid graft polyethylene and the like, ethylene- (meth) acrylic acid copolymer (EAA), ethylene- (meth) acrylic acid ethyl copolymer (EEA), ionomers such as ethylene- (meth) acrylic acid copolymer Alkali metal salt,
Examples thereof include alkaline earth metal salts and ammonium salts.

Examples of the thermoplastic resin (including homopolymer and copolymer) belonging to the above-mentioned polyolefin resin include, for example, polyethylene resin, polypropylene resin, poly-1-
It may be one or more kinds selected from butene resin, poly-4-methyl-1-pentene resin and the like, two or more kinds of combination resins selected from the above resins or a thermoplastic elastomer. This thermoplastic elastomer is one or more of the resins listed above or 2
It may be a combination of at least one combination resin and the elastomer described below or a semi-crosslinking (partial vulcanization) thereof.

The elastomer component of this thermoplastic elastomer is an olefinic elastomer selected from ethylene-propylene copolymer elastomer, ethylene-1-butene copolymer elastomer, propylene-1-butene copolymer elastomer, or these copolymer elastomers as the third component. An ethylidene norbornene selected from non-conjugated dienes as
It also includes those containing hexadiene, dicyclopentadiene and the like.

The resin mainly constituting the matrix of the ultraviolet blocking layer is a homopolymer of the above α-olefin and / or
Or, not limited to their mutual copolymers, for example, ethylene and
It may be a commonly known "ionomer" as an alkali metal salt such as sodium salt and potassium salt of a copolymer with (meth) acrylic acid, zinc salt, magnesium salt and the like.

Further, the thermoplastic resin or the thermoplastic elastomer ("thermoplastic resins") in the above-mentioned ultraviolet blocking layer occupies the main component of the matrix. <2.2. Material of Migration Blocking Layer> The migration blocking layer is extremely important and plays various roles as described above. First, the material selected for that purpose is that it is a resin containing oxygen atoms. Here "containing oxygen atom"
Means "containing oxygen in the molecule in a bound state". However, this "bond in the molecule" is not limited to "bond in the molecular main chain", but also includes the case where the substituent bonded to the carbon atom constituting the molecular chain is an oxygen-containing group. There are various cases where this "substituent is an oxygen-containing group",
This substituent is, for example, a hydroxyl group (—OH) or a carboxyl group.
(-COOH), acyloxy group (-OCOR), acyl group (-C
OR), a carbonyl group (> CO), a formyl group (-CHO) and the like.

Further, the materials of both transition blocking layers laminated directly or indirectly on both sides of the ultraviolet blocking layer may be different from each other, depending on the roles of the respective migration blocking layers. It is most important to select the optimum material.

Examples of the above-mentioned "oxygen atom-containing thermoplastic resin" are polyamide resin (nylon), thermoplastic polyester (resin), especially PET (polyethylene terephthalate),
Examples of the thermoplastic resin include PBT (poly-1,4-butylene terephthalate) and the like, ethylene-vinyl alcohol copolymer resin (EVOH), polycarbonate (PC) and the like as main components.

The migration inhibiting layer may be a composition comprising a combination of two or more of the above oxygen atom-containing resins,
For example, a composition of a polyamide resin (6-nylon or 6,6-nylon etc.) and an ethylene-vinyl alcohol copolymer resin can be mentioned. The content ratio of both in this composition is 50/50 to 90/10 (or 1 by weight).
0/90).

The migration-preventing layer may contain an oxygen atom-free resin, such as a polyolefin resin, as long as the migration-preventing function is not substantially reduced (the reduction is hardly recognized). Here, the term "amount that does not substantially reduce the migration inhibiting function" refers to an amount of 30% by weight or less, preferably 20% by weight or less, as a content in the migration inhibiting layer.

<2.3. Material of Adhesive Polymer Layer> In the basic composite film of the present invention, the adhesive polymer layer has both layers when the ultraviolet blocking layer and the migration blocking layer are laminated by a coextrusion molding method. There are many intervening things. In addition, it may be interposed between the migration-preventing layer and the outer skin layer and between the migration-preventing layer and the endothelial layer in order to mediate the adhesion of both layers.

Specific examples of the modified polymer constituting the adhesive polymer layer are as follows: <2.3.1> Modified olefin polymer having unsaturated carboxylic acid itself or an anhydride thereof as a modifier. (Resin, thermoplastic elastomer and elastomer) For example, maleic anhydride (MA
H) as a modifying agent; <2.3.2> modified olefin polymer having a alkenyl ester of a saturated carboxylic acid as a modifying agent, for example, ethylene-vinyl acetate copolymer (EVA); <2.3.3> α-olefin-unsaturated carboxylic acid ester copolymer, for example, ethylene-ethyl acrylate copolymer resin
(EEA).

<2.4. Laminating Adhesive> The usual laminating method for a plastic film is an extrusion laminating method in which a large amount of a low-density polyethylene resin is used as an adhesive for laminating. In many cases, the adhesive used in the lamination method (laminating method) called dry lamination which is another method is a polyurethane (PU) -based polymer,
Although this is a laminating method using this as a solution of an organic solvent, a non-solvent laminating (laminating without organic solvent) method can also be used as another laminating method. In the non-solvent laminating method, a polycondensable adhesive is used instead of the solvent.

<3. Other layers that can be added><3.1. Endothelial layer> The endothelial layer is the surface of the basic composite film when it is not preferable to use the basic composite film of the present invention. It is a layer (so-called sealant layer) that is laminated on the side that comes into direct contact with the content (object to be packaged) and imparts a heat-sealing function to the basic composite film when used as a packaging bag. That is, originally, the basic composite film of the present invention can exhibit the desired performance or effect by itself.

A laminate of two or more layers obtained by treating the surface (outer surface) on the side not contacting the article to be packaged with the endothelial layer for the purpose of imparting or improving the adhesiveness or laminating it with a layer having other properties. You may comprise.

<3.2. Outer skin layer> The outer skin layer is the surface of the basic composite film and does not face the contents (the object to be packaged) when it is not preferable to use the basic composite film of the present invention. It is a layer laminated on the side (outer side) to protect the basic composite film. That is, basically, the basic composite film of the present invention can exhibit the desired performance or effect by itself.

However, in the actual use form, the outside of the basic composite film may be exposed to a harsh environment, a heavy load use condition or other intense conditions. The outer skin layer is responsible for receiving these external effects and preventing them from reaching the inside. Therefore, it is sufficient in most cases to use existing materials appropriately selected or combined in accordance with the application, use environment and the like. The outer skin layer may also be used in the form of a laminate having two or more layers, if necessary.

<4. Practical composite film; film for packaging material> The practical composite film of the present invention and the film for packaging material which is the main use thereof are described in the above section "<1. Basic composite film>". In some cases, the basic composite film can also be used. However, it is in principle important to be able to withstand the properties of the object to be packaged, the environment used as the packaging material, the use conditions, and the like.

First, considering the basic composite film of the present invention as a practical composite film, for example, a packaging material, in the basic composite film of the present invention, each layer constituting the basic composite film is further used as a practical composite film. An important additional layer is also at least the inner skin layer, which is usually provided on the surface of the migration-preventing layer facing the package, and the outer skin layer, which is usually provided on the surface of the non-package-facing side. It is often preferable to have a limit.

What role does the inner layer and the outer layer play?
It has already been mentioned in each section whether or not it is preferable to provide properties and the like. Since these additional layers constitute an application invention of the basic composite film of the present invention,
In some cases, there is room for omission or improvement to special materials.

<5. Manufacturing Method of Basic Composite Film and Practical Composite Film> The basic composite film of the present invention and a practical composite film based on the same, for example, in order to manufacture a laminated film for packaging material, an organic ultraviolet ray is used. An ultraviolet blocking layer in which the absorbent is kneaded to a concentration of at least room temperature solubility and a migration blocking layer are laminated directly or indirectly on both sides of the ultraviolet blocking layer, in which case at least one side of both migration blocking layers is subjected to a coextrusion molding method ( It is essential to be laminated on the surface of the ultraviolet blocking layer by the T-die molding method and the inflation molding method.

That is, in the case of lamination by the coextrusion molding method,
Since the ultraviolet blocking layer is covered with the migration blocking layer from the forming process of the basic composite film, blooming cannot occur even if the organic ultraviolet absorber is kneaded at a room temperature solubility or higher.

However, other laminating methods other than the co-extrusion molding method, for example, the organic ultraviolet absorbent kneading layer and the migration preventing layer are produced as separate films in advance, and then the both films are adhered with an adhesive or the like. According to the laminating method, that is, according to the laminating method, blooming of the organic ultraviolet absorber occurs from the film in which the organic ultraviolet absorber is kneaded to have a room temperature solubility or higher before the completion of the laminating operation. This blooming not only reduces the kneading amount, but also deteriorates the ultraviolet blocking performance, and the organic ultraviolet absorber bloomed on the film surface hinders the laminating operation.

Due to the above reasons, it is extremely difficult to produce a basic composite film and a practical composite film that can be used practically by the above-mentioned manufacturing method. In particular, the method of sequentially sticking both transition blocking layers located on both sides of the ultraviolet blocking layer to the ultraviolet blocking layer cannot be a manufacturing method that can be put to practical use. At least one of the migration blocking layers needs to be pre-laminated with the ultraviolet blocking layer by coextrusion.

In order to mold the basic composite film and the practical composite film of the present invention, which are excellent in the ability to block ultraviolet rays, it is usual to use a system in which a separate extruder is used for each constituent layer. As described above, in addition to organic UV absorbers and the like, which are essential additives for polymers such as resins that become matrices in different extruders for each constituent layer, various types of stabilizers added to ordinary molded products A molding composition in which agents, auxiliaries, lubricants and other useful additives are blended as necessary is uniformly melt-kneaded in each extruder, and the resin flow extruded achieves a predetermined layer structure. As described above, the desired basic composite film or a practical composite film in which an additional layer is further laminated is obtained by fusion-bonding with each other via a multilayer die, for example, a laminated film for packaging material.

When the basic composite film and the practical composite film of the present invention, which are excellent in the ability to block ultraviolet rays, are formed by the so-called "inflation molding method", both composite films obtained are in principle further layer thickness (film thickness). It can be used as a film for packaging materials such as foods without thinning it, but when it is formed as a cast film such as a T-die film, it is further stretched and processed to a layer thickness conforming to the standard. It may be thinned.

As the stretching apparatus, either a uniaxial stretching apparatus or a biaxial stretching apparatus is appropriately selected, and in this case, in both uniaxial stretching processing and biaxial stretching processing, a single stage is performed up to the desired stretching ratio. It is usual to divide the stretching operation into multiple stages and gradually raise it to a predetermined value than in the case of stretching, and avoid unfavorable results such as breakage and tearing of the stretched object due to high stretching. it can. Further, in the biaxial stretching treatment, the stretching ratios in the longitudinal direction and the transverse direction may be different from each other, and the conditions can be set so that the appropriate stretching treatment is performed depending on the application and purpose of use of the product. .

[0071]

The following various effects can be achieved by using the basic composite film of the present invention and the practical composite film having at least the inner layer and / or the outer layer laminated thereon. Further, the above-mentioned basic composite film and practical composite film could be formed for the first time by using the multilayer coextrusion molding method which is the production method of the present invention: (1) In the near ultraviolet region (wavelength 320 to 390 nm) It absorbs and removes the belonging ultraviolet rays at a high level of 90% or more, and the visible light absorption and removal rate is 30% or less, preferably 20% or less,
More preferably, it could be suppressed to a level of 10% or less (transmittance was kept at a level of 70% or more).

As a result, foods, cosmetics, pharmaceuticals and other chemicals covered with the film excellent in ultraviolet ray blocking property undergo undesired changes such as discoloration, deterioration and deterioration due to the influence of near ultraviolet rays. (2) It has the advantage that blooming does not occur on the surface of the basic composite film or the applied film based on it even though it is thin for packaging material and used for a long time. 3) It can sufficiently meet various practical performances required for ordinary packaging material films, which are important uses of applied films.

[0073]

EXAMPLES The present invention will be specifically described below based on examples with reference to comparative examples as the case may be. The present invention is not limited to these examples.

[0074]

Example 1 Three screw type extruders were prepared, and the No. 1 extruder (L / D = 26) was used as an oxygen atom-containing resin.
-Polyamide resin (6-NY) [relative viscosity 3.4; room temperature specific gravity 1.
13] was charged and melt-kneaded at a temperature of 260 ° C. to prepare a molding composition for the outer migration inhibiting layer located on the outer skin layer side in the migration inhibiting layer. The No. 2 extruder (L / D = 26) has a maleic anhydride-modified low-density polyethylene (AD) [density 0.92 g / cc; MI (1
90 ° C; 2.16kgf) 1.8g / 10min] 100 parts by weight of a benzotriazole compound as an organic UV absorber A [trade name: Tinuvin 326 (manufactured by Ciba Geigy)] 3
Parts by weight were kneaded and mixed at a temperature of 220 ° C. by a melt kneading means to prepare a composition for an ultraviolet blocking layer. No. 3 extruder (L / D = 26) has a different oxygen atom-containing resin as ethylene-vinyl alcohol copolymer resin (EVOH) [room temperature specific gravity 1.19; MI (190 ° C; 2.16kgf) 1.5g / 10 min] and melt-kneaded at a temperature of 220 ° C. to prepare a molding composition for the inner migration preventing layer.

Next, a resin flow of the above-mentioned molding composition was supplied from each extruder to a common multi-layer die to form a layer structure of an outer migration blocking layer, an ultraviolet blocking layer and an inner migration blocking layer via the dies. After the resin streams were combined and laminated, the multilayer resin stream was introduced into an annular die (diameter 350 mm) and inflation molding was performed at an expansion ratio of 1 to obtain a basic composite film (folding width 550 mm; overall film thickness 60 μm). The layer structure of the obtained basic composite film was 6-NY (outer migration blocking layer) // (ultraviolet absorber A / AD) // EVOH (inner migration blocking layer).

Further, the presence / absence of blooming of the ultraviolet absorbent from this basic composite film was visually judged on the outside and inside thereof after being left at room temperature for a long period of time. The result of "none" was obtained.

The above results are shown in Table 1 in the form of layer constitution, each layer thickness, kind and content of ultraviolet absorber, production conditions of the composite film, characteristic values of the obtained composite film and the like. <Production of Practical Composite Film> Using the basic composite film composed of the three layers obtained above, the inside of the migration prevention layer (inner migration prevention layer) composed of the ethylene-vinyl alcohol copolymer resin (EVOH) Low density polyethylene as the skin layer [density 0.92g / cc; MI (190 ℃; 2.16kgf) 1.0g /
10 min] Films (average film thickness 30 μm) were laminated by a dry laminating method.

On the other hand, a biaxially stretched polyethylene terephthalate film (OPE) is formed as a skin layer on the surface of the migration prevention layer (outer migration prevention layer) made of a polyamide resin on the opposite side.
T: average film thickness 12 μm) was laminated by a dry lamination method. The physical properties of the obtained practical composite film were as follows. The results are also shown in Table 1: Tensile strength (kgf / mm ² ): 7.0; Tensile elongation (%): 300; Tensile impact strength (kgf / cm / cm): 15; Heat sealing temperature (℃) : 120; UV transmittance (wavelength: 320 to 390 nm): 1%; Visible light transmittance (wavelength: 600 nm): 85%. Blooming UV absorber: (outside) none after 1 year;
(Inside) None after 1 year; (Leave at room temperature for a long time; visual judgment) Oxygen gas permeability (23 ℃; 65% RH): 0.6 (cc / m ² · Day ・ at
m).

[0079]

Comparative Example 1 <Experiment 1-i> A low density polyethylene layer was used instead of the ethylene-vinyl alcohol copolymer (EVOH) layer forming the inner migration blocking layer in the basic composite film obtained in Example 1. Co-extrusion lamination was performed to obtain a three-layer laminated film.
The results are shown in Table 1 in the form of layer constitution, thickness of each layer, kind and content of ultraviolet absorber, production conditions of the composite film, characteristic values of the obtained composite film, and the like. As a precaution, when the presence or absence of bloom was shown, the outer migration-preventing layer showed no bloom even after 1 year, while the inner migration-preventing layer showed bloom after 6 months. <Experiment 1-ii> A low density polyethylene layer was used instead of the polyamide resin layer forming the outer migration preventing layer in the basic composite film obtained in Example 1 to coextrude and laminate to obtain a three-layer laminated film. The results are shown in Table 1 in the form of layer constitution, thickness of each layer, kind and content of ultraviolet absorber, production conditions of the composite film, characteristic values of the obtained composite film, and the like. As a precaution, the presence or absence of bloom showed that the outer migration block layer had bloomed after 3 months, whereas the inner migration block layer did not bloom after one year.

[0080]

Example 2 In place of the adhesive polymer which is the base resin (matrix resin) of the ultraviolet blocking layer in the basic composite film of Example 1, unmodified low density polyethylene [density 0.9
2 g / cc; MI (190 ° C .; 2.16 kgf) 1.0 g / 10 min] was added to 100 parts by weight of the same ultraviolet absorber as in Example 1 at a ratio of 2 parts by weight, and melt kneading was performed. To prepare a composition for the ultraviolet blocking layer.

Maleic anhydride modified as an adhesive polymer for firmly bonding the ultraviolet blocking layer and the outer migration blocking layer and the inner migration blocking layer made of the same resin as in Example 1 to each other. Using the low density polyethylene [density 0.92 g / cc; MI (190 ° C; 2.16 kgf) 1.8 g / 10 min], the above outer migration prevention layer /// adhesive polymer from 5 single screw extruders Layer // UV blocking layer // adhesive polymer layer // inner migration blocking layer were coextruded. ◆ 6-polyamide resin for the first extruder (L / D = 26)
(6-NY) [relative viscosity 3; room temperature specific gravity 1.13] was charged and melt kneading was performed at a temperature of 260 ° C. to extrude the resin flow for the outer migration inhibiting layer located on the outer skin layer side. ◆ No. 2 extruder (L / D = 26) has adhesive polyethylene resin (AD) [density 0.92g / cc; MI (190 ° C; 2.16kgf) 1.8
g / 10 min] was charged and the molten resin flow was extruded. ◆ The No. 3 extruder (L / D = 26) was charged with the above composition for the ultraviolet blocking layer and melt-kneaded at a temperature of 220 ° C.
The resin stream for the UV blocking layer was extruded. ◆ No. 4 extruder (L / D = 26) has an adhesive polyethylene resin (AD) [density 0.92g / cc] as an adhesive polymer for bonding between the ultraviolet blocking layer and one migration blocking layer. MI (190
C .; 2.16 kgf) 1.8 g / 10 min] was charged and the molten resin flow was extruded. ◆ No. 5 extruder (L / D = 26) has ethylene-vinyl alcohol copolymer resin (EVOH) [room temperature specific gravity 1.19; MI
(190 ℃; 2.16kgf) 1.5g / 10min] and temperature 220
Melt kneading was carried out at 0 ° C. to prepare a resin flow for the inner migration preventing layer.

Next, a resin flow was supplied from each extruder to a common multi-layer die, and the resin flow was co-extruded and laminated so as to have a layer structure of 5 layers, and then led to an annular die (diameter 350 mm). Inflation molding was performed at a swelling ratio of 1 to obtain a basic composite film of the present invention (folding width 550 mm; overall thickness 7
0 μm).

The layer structure of this 5-layer laminated film (including the adhesive polymer layer) is 6-NY (10 μm) // AD (10 μm) //
(Organic UV absorber / LDPE) (20μm) // AD (1
0 μm) // EVOH (10 μm).

Further, the presence / absence of blooming of the ultraviolet absorbent from this basic composite film was visually judged on the outside and inside thereof after being left at room temperature for a long period of time. The result of "none" was obtained.

The above results are shown in Table 1 in the form of the layer constitution, each layer thickness, the kind and content of the ultraviolet absorber and the production conditions of the composite film. <Production of Practical Composite Film> A low density polyethylene resin film as an inner layer on the EVOH layer side of the above five-layer laminated film [average film thickness 30 μm; density 0.92 g / cc; MI (190
℃; 2.16kgf) 1.0g / 10min] by dry lamination by a conventional method, and biaxially oriented polypropylene resin film (OPP) (average film thickness 25μm) as a skin layer on the other side.
Were laminated by dry lamination by a conventional method to obtain a 7-layer practical composite film (average overall film thickness: 115 μm).

The physical properties of the obtained practical composite film for packaging material were as follows. The results are also shown in Table 1: Tensile strength (kgf / mm ² ): 7.0; Tensile elongation (%): 100; Tensile impact strength (kgf / cm / cm): 20; Heat sealing temperature (° C) : 125; UV transmittance (wavelength: 320 to 390 nm): 3%; Visible light transmittance (wavelength: 600 nm): 85%. Blooming UV absorber: (outside) none after 1 year;
(Inside) None after 1 year; (Leave at room temperature for a long time; Visual judgment) Oxygen gas permeability (23 ℃; 65% RH): 1.2 (cc / m ² · Day ・ at)
m).

[0087]

Example 3 Instead of forming an ultraviolet blocking layer for the purpose of preparing a practical composite film, the same organic ultraviolet absorber as in Example 1 was used to prepare a composition for an ultraviolet blocking layer.

Five screw type extruders were prepared and operated as follows. The conditions and the like at that time were as shown in Table 1, and consisted of 5 layers, and only the endothelial layer was added. A practical composite film was obtained: No. 1 extruder (L / D = 26) had 6-NY resin (room temperature specific gravity of 1.1).
3; Relative viscosity 3.4) was charged and melt kneading was performed at a temperature of 260 ° C. to prepare a molding composition for the outer migration inhibiting layer.

The No. 2 extruder (L / D = 26) had an adhesive polymer (resin) (AD) [adhesive polyethylene resin (density 0.92 g / cc; MI) as a molding composition for the ultraviolet blocking layer. (190 ℃; 2.16kg
f) 1 g / 10 min)] was charged and melt-kneaded at a temperature of 220 ° C.

The No. 3 extruder (L / D = 26) contained ethylene-vinyl alcohol copolymer resin (EVOH) (room temperature specific gravity 1.19;
MI (190 ℃; 2.16kgf) 1.5g / 10min)) and temperature 2
The mixture was melt-kneaded at 20 ° C. to prepare a molding composition for the inner migration preventing layer.

In the No. 4 extruder (L / D = 26), an adhesive polymer (resin) (AD) [adhesive polyethylene resin (density 0.92 g / cc; MI (190 ℃; 2.16kg
f) 1 g / 10 min)] was charged and melt-kneaded at a temperature of 220 ° C.

No. 5 extruder (L / D = 26) had a low-density polyethylene resin (LDPE) as a molding composition for the inner layer (density: 0.92 g / cc; MI (190 ° C .; 2.16 kgf) 1 g / 10 min)] and melt-kneaded at a temperature of 220 ° C.

Next, a resin stream is fed from each extruder to a common multi-layer die to form an outer migration blocking layer // ultraviolet blocking layer //
The resin flow is extruded and laminated through a common die so as to form a five-layer structure of an inner migration blocking layer // adhesive polymer layer // endothelial layer, and then this multilayer resin flow is transferred to an annular die (diameter 350 mm). Induction molding was carried out at a swelling ratio (blow ratio) of 1 to obtain a basic composite film (fold width 550 mm; overall film thickness 7).
0 μm). The layer thicknesses of both migration inhibiting layers in the obtained basic composite film were all about 10 μm.

Further, the presence / absence of blooming of the ultraviolet absorber from the practical composite film was visually judged on the outside and inside thereof after being left at room temperature for a long time, and the results are shown below. The above results, the layer constitution, each layer thickness, the kind and content of the ultraviolet absorber, the manufacturing conditions of the composite film, and the physical properties of the obtained practical composite film were as follows. The results are shown in Table 1: Tensile strength (kgf / mm ² ): 3.3; Tensile elongation (%): 500; Tensile impact strength (kgf / cm / cm): 10; Heat sealing temperature (° C): 120; UV transmittance (wavelength: 320 to 390 nm): 5%; Visible light transmittance (wavelength: 600 nm): 85%. Blooming UV absorber: (outside) none after 1 year;
(Inside) None after 1 year; (Leave at room temperature for a long time; visual judgment) Oxygen gas permeability (23 ℃; 65% RH): 1.2 (cc / m ²・ Day ・ at
m).

[0095]

[Example 4] As a basic composite film, an outer migration preventing layer was provided with an ethylene-vinyl alcohol copolymer resin (EVOH).
80 wt% and low density polyethylene (LDPE) 20 wt%
And a low density polyethylene resin with 80% by weight of polyamide resin (NY) as the inner migration preventing layer.
The same operation as in Example 2 was carried out except that it was formed in a mixture with 20% by weight of (LDPE). In addition, in this Example 4, two kinds of the following A and B from the benzotriazole-based compounds were combined and used as the ultraviolet absorber in an amount of 50% by weight. The benzotriazole A has a trade name “Tinuvin 326”, and the benzotriazole B has a trade name “Tinuvin 328”.

Five screw type extruders were prepared, and a basic composite film was prepared in the same manner as in Example 2 except for the above layer constitution and each layer thickness. In addition, Table 2 shows the results of the visual determination of the presence or absence of blooming of the ultraviolet absorbent from the basic composite film after left at room temperature for a long time on the outside and the inside.

Table 2 shows the above-mentioned results regarding the layer constitution, each layer thickness, the kind and content of the ultraviolet absorber, the production conditions of the composite film and the physical properties of the obtained basic composite film.

<Preparation of Practical Composite Film> On the outer surface of the basic composite film obtained in the previous step, an outer migration-preventing layer composed of an ethylene-vinyl alcohol copolymer resin (EVOH) and a small amount of low density polyethylene resin (LDPE) was formed. An OPP film (layer thickness: 25 μm) for the outer skin layer is laminated on the surface by a dry lamination method, while the migration prevention layer composed of a polyamide resin and a small amount of low density polyethylene resin (LDPE) is formed on the surface of the outer layer for the inner skin layer. A film made of the same resin as the low-density polyethylene resin for forming the ultraviolet blocking layer as the density polyethylene resin was laminated by the dry lamination method to obtain a 9-layer practical composite film. This practical composite film is particularly useful for food packaging.

In addition, Table 2 shows the results of visual determination of the presence or absence of blooming of the ultraviolet absorbent from this basic composite film after left at room temperature for a long time on the outside and inside thereof. The above results, the layer constitution, each layer thickness, the kind and content of the ultraviolet absorber, the production conditions of the composite film, and the physical properties of the obtained practical composite film were as follows. The results are also shown in Table 2: Tensile strength (kgf / mm ² ): 8.0; UV transmittance (wavelength: 320 to 390 nm): 5%; Visible light transmittance (wavelength: 600 nm): 80 %. Blooming UV absorber: (outside) none after 1 year;
(Inside) None after 1 year; (Leave at room temperature for a long time; visual judgment) Oxygen gas permeability (23 ℃; 65% RH): 1.0 (cc / m ² · Day ・ at
m).

[0100]

Example 5 A practical composite film of 5 layers was prepared by the coextrusion laminating method in which the layer thickness of each layer was changed in the same combination of layers as in Example 3. The physical properties of the obtained practical composite film were as follows. The results are shown in Table 2: Tensile strength (kgf / mm ² ): 4.5; UV transmittance (wavelength: 320 to 390 nm): 3%; Visible light transmittance (wavelength: 600 nm): 85% . Blooming UV absorber: (outside) none after 1 year;
(Inside) None after 1 year; (Leave at room temperature for a long time; visual judgment) Oxygen gas permeability (23 ℃; 65% RH): 0.6 (cc / m ² · Day ・ at
m).

[0101]

Example 6 A 5-layer practical composite film was prepared by the coextrusion laminating method in which the layer thickness of each layer was changed in the same combination of layers as in Example 3. The physical properties of the obtained practical composite film were as follows. The results are shown in Table 2: Tensile strength (kgf / mm ² ): 3.0; UV transmittance (wavelength: 320 to 390 nm): 1%; Visible light transmittance (wavelength: 600 nm): 90% . Blooming UV absorber: (outside) none after 1 year;
(Inside) None after 1 year; (Leave at room temperature for a long time; visual judgment) Oxygen gas permeability (23 ℃; 65% RH): 2.5 (cc / m ² · Day ・ at)
m).

[0102]

Example 7 A 5-layer practical composite film was prepared by the coextrusion laminating method in which the layer thickness of each layer was changed in the same combination of layers as in Example 3. The physical properties of the obtained practical composite film were as follows. The results are shown in Table 2: Tensile strength (kgf / mm ² ): 3.2; UV transmittance (wavelength: 320 to 390 nm): 15%; Visible light transmittance (wavelength: 600 nm): 87% . Blooming UV absorber: (outside) none after 1 year;
(Inside) None after 1 year; (Leave at room temperature for a long time; visual judgment) Oxygen gas permeability (23 ℃; 65% RH): 1.2 (cc / m ² · Day ・ at)
m).

[0103]

[Table 1]

[0104]

[Table 2]

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location B32B 27/28 101 B32B 27/28 101 27/30 27/30 27/32 27/32 27/34 27/34 27/36 27/36 102 102 C08K 5/3467 KBL C08K 5/3467 KBL // B29L 9:00

Claims (13)

[Claims] 1. A migration inhibitor for an organic UV absorber comprising an oxygen atom-containing thermoplastic resin on both sides of a UV blocking layer in which a thermoplastic polymer is blended with an organic UV absorber at a concentration equal to or higher than its room temperature solubility. A basic composite film, which is a laminated film in which layers are laminated, and in which at least one of the migration prevention layers and an ultraviolet blocking layer are laminated by coextrusion and which is rich in ultraviolet blocking property and transparency. 2. The thermoplastic polymer is a polyolefin resin,
The basic composite film according to claim 1, which comprises an ionomer resin, an adhesive polyolefin polymer or an olefin-based thermoplastic elastomer as a main component. 3. The thermoplastic resin containing an oxygen atom contains a polyamide resin, a polycarbonate resin, a thermoplastic polyester resin, an ethylene-vinyl alcohol copolymer resin or an ethylene-alkyl (meth) acrylate copolymer resin as a main component. Or the basic composite film described in 2. 4. The basic composite film according to claim 1, wherein the migration inhibiting layer has an average layer thickness of 3 to 70 μm. 5. The basic composite film according to claim 1, wherein the organic ultraviolet absorber is contained in the basic composite film in an amount of 0.1 g / m ² or more (the film area). 6. An ultraviolet ray having a wavelength range of 320 to 390 nm is absorbed and removed so that its transmittance is 20% or less, and a wavelength range of 400 to
The basic composite film according to any one of claims 1 to 5, which contains an organic ultraviolet absorber that transmits visible light of 800 nm to a transmittance of 70% or more. 7. A thermoplastic polymer containing a light beam in the near ultraviolet region of 8
A migration blocking layer made of an oxygen atom-containing resin is laminated on one side of an ultraviolet blocking layer containing an organic ultraviolet absorbing agent that absorbs 0% or more and transmits 70% or more of visible light at a concentration of solubility at room temperature or higher. On the opposite side of the layer, a migration blocking layer made of the same oxygen atom-containing resin as or different from the oxygen atom-containing resin is laminated, and at least one of both migration blocking layers is coextruded on the ultraviolet blocking layer. , A polyolefin resin layer is laminated as an endothelial layer on the surface of any one of the migration prevention layers by coextrusion lamination or via a laminating adhesive, or a polypropylene resin, a polyamide resin and a thermoplastic polyester via laminating adhesive. A stretched film selected from resins is laminated as the outer skin layer, or the outer skin layer and the inner skin layer are laminated together. Practical composite film formed from the basic composite film according to any one of Motomeko 1-6. 8. The practical composite film according to claim 7, wherein the thermoplastic polymer forming the ultraviolet blocking layer has a polyolefin resin or an adhesive polyolefin polymer as a main component, and the organic ultraviolet absorber is a benzotriazole compound. The migration blocking layer containing a polyamide resin as a main component has an average layer thickness of 5 to 70 μm on one side of the ultraviolet blocking layer containing 2% by weight or more of which the solubility is at room temperature or more.
The transfer blocking layer containing ethylene-vinyl alcohol copolymer resin as a main component is stacked on the opposite side with an average layer thickness of 3 to 30 μm, and at least one of the transfer blocking layers is the surface of the ultraviolet blocking layer. A practical composite film formed from a basic composite film laminated by coextrusion with. 9. An adhesive polymer layer is provided at one or more locations between the ultraviolet blocking layer and the migration blocking layer, between the migration blocking layer and the outer skin layer, and between the migration blocking layer and the endothelial layer. The basic composite film according to any one of 1 to 6 or the practical composite film according to claim 7 or 8. 10. The basic composite film according to claim 1, wherein the composite film contains a benzotriazole compound as an organic ultraviolet absorber in an amount of 0.1 g / m ² or more (the film area). Alternatively, the practical composite film according to any one of claims 7 to 9. 11. A packaging comprising a basic composite film according to any one of claims 1 to 6, a practical composite film according to any one of claims 7 to 10 or a laminate of a basic composite film and a practical composite film. Composite film. 12. An ultraviolet ray absorbing layer-forming adhesive polymer and an organic ultraviolet absorber, which have a light absorption removal rate in the near ultraviolet region of 80% or more and a light transmittance of 70% in the visible region.
To prepare a composition for the ultraviolet blocking layer by melt-kneading a mixture containing the above organic compounds at a concentration of room temperature solubility or higher,
Then, the oxygen atom-containing resin is extruded from the extruder No. 1 of the three extruders to form a resin flow for the migration prevention layer, and the composition for the ultraviolet ray blocking layer is extruded from the extruder No. 2. A resin flow for the ultraviolet blocking layer is formed, and an oxygen atom-containing resin different from or the same as the oxygen atom-containing resin is extruded from the No. 3 extruder to form a resin flow for the migration inhibiting layer, and then, Is the resin flow from each extruder supplied to a common die and co-extruded to form a layer structure of migration block layer // UV blocking layer // migration block layer and inflation molding the laminated multilayer resin flow? Alternatively, a method for producing a basic composite film by subjecting the above multilayer resin flow to multilayer T die molding. 13. The method according to claim 12, except that the ultraviolet blocking layer contains a thermoplastic polymer and a benzotriazole compound as an organic ultraviolet absorber at a concentration of solubility at room temperature or higher. , Using an additional one extruder as the No. 4 extruder, between the resin flow from the No. 1 extruder and the resin flow from the No. 2 extruder (“between 1-2”) and the No. 2 extruder. Between the resin flow from the extruder and the resin flow from the No. 3 extruder (“between 2-3”), the adhesive polymer stream is supplied from the No. 4 extruder, or by adding two additional units. The extruders are used as a No. 4 extruder and a No. 5 extruder, respectively, and between the resin flow from the No. 1 extruder and the resin flow from the No. 2 extruder ("1-2
Between the resin flow from the No. 2 extruder and the resin flow from the No. 3 extruder ("2- No. 4 extruder or No. 5 extruder in "3"", and the adhesive polymer stream is supplied from an extruder different from the extruder that supplied the adhesive polymer stream in" 1-2 ". Migration prevention layer // adhesive polymer layer by feeding the resin flow from each extruder to a common die at
// ultraviolet blocking layer // adhesive polymer layer // co-extrusion of resin flow and adhesive polymer flow so as to form a layer structure of migration prevention layer, and inflation molding of a multilayer resin flow laminated A method for producing a basic composite film having an interlayer adhesive layer added by multi-layer T-die molding of a multilayer resin flow.