JP2011143691A - Hygroscopic laminate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hygroscopic laminate which has a function to suppress and retard moisture absorption in the initial stage after production and can demonstrate original moisture absorption performance as the necessity requires. <P>SOLUTION: The hygroscopic laminate 10 comprises a moisture absorbing film 1 and a pair of release films 2 holding the moisture absorbing film 1. The moisture absorbing film 1 includes a moisture absorbing layer 3 made of a binder resin and a moisture adsorbing substance and an adhesive layer 4 set on at least one side of the moisture absorbing layer 3. The release film 2 is produced from a release layer 6 made of a cyclic polyolefin resin and a support layer 5. The moisture absorbing film 1 and the release film 2 are laminated by coextrusion between the moisture absorbing layer 3 or the adhesive layer 4 and the release layer 6. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a hygroscopic laminate, and more particularly to a hygroscopic laminate using a laminate material made of a resin composition containing an inorganic compound having hygroscopic properties.

  In the field of organic devices such as organic EL elements, there are many cases in which contact with water vapor or gas in the air is hated during the manufacturing process. Therefore, in recent years, the demand for materials having a function of adsorbing water vapor and gas is increasing, and various films having such a function have been proposed. For example, Patent Document 1 discloses an organic EL panel in which a sheet-like desiccant containing a binder resin, a dry component, and a particulate resin is provided on an organic EL element.

  By the way, for film with water vapor or gas adsorption function, how to control film moisture absorption at each stage of production, distribution, storage, sales, etc., in order to secure the adsorption function during actual use Is an important issue. As a means for solving this problem, for example, a method of lowering the space in which the film manufacturing process is performed under low humidity is conceivable.

  Patent Document 2 discloses a hygroscopic / barrier laminated packaging material that is controlled so as to exhibit a hygroscopic function when heat-sealed using an uneven heat seal bar, and a packaging body using the same. Has been.

JP 2009-26648 A (Claims etc.) JP 2004-331079 A (Claims etc.)

  However, the method of reducing the humidity of the film production atmosphere has a problem that it is not simple because special equipment is required and more strict management is required. Further, the technique described in Patent Document 2 also has a problem that a special device must be prepared for implementation, and an increase in burden is inevitable. Therefore, establishment of a technique capable of suppressing or delaying moisture absorption in the initial stage after manufacture has been demanded without requiring special devices and facilities as in the prior art.

  Accordingly, an object of the present invention is to solve the above-mentioned problems, to have a function of suppressing or delaying moisture absorption in the initial stage after production, and capable of exhibiting original moisture absorption performance as required. Is to provide.

  As a result of diligent study, the present inventor found that the above problem can be solved by adopting a structure in which a moisture-absorbing film exhibiting moisture-absorbing performance is sandwiched between release films including a release layer made of a cyclic polyolefin resin. The invention has been completed.

That is, the present invention is a hygroscopic laminate comprising a hygroscopic film and a pair of release films sandwiching the hygroscopic film,
The moisture-absorbing film comprises a moisture-absorbing layer composed of a binder resin and a moisture-adsorbing substance, and an adhesive layer provided on one or both surfaces of the moisture-absorbing layer, and the release film is a release layer composed of a cyclic polyolefin resin; The moisture absorbing film and the release film are laminated by coextrusion between the moisture absorbing layer or the adhesive layer and the release layer. is there.

  In this invention, it is preferable that the said support layer of the said peeling film is 25-60 micrometers in thickness, and consists of a polyethylene resin. Moreover, the thickness of the release layer of the release film is preferably 5 to 20 μm. Furthermore, it is preferable that the binder resin of the hygroscopic layer of the hygroscopic film is an acrylic thermoplastic elastomer having an MFR measured at a temperature of 190 ° C. and a load of 2.16 kg of 5 to 40 g / 10 min.

  Furthermore, the moisture-adsorbing substance of the moisture-absorbing layer of the moisture-absorbing film is at least selected from the group consisting of alkali metal oxides, alkaline earth metal oxides, sulfates, metal halides, perchloric acid, and organic substances. A chemical water-adsorbing material consisting of one kind is preferred. Furthermore, it is preferable that the weight ratio of the binder resin and the moisture-adsorbing substance in the moisture-absorbing layer of the moisture-absorbing film is 80 to 40 parts by mass of the moisture-adsorbing substance with respect to 20 to 60 parts by mass of the binder resin.

  Furthermore, the pressure-sensitive adhesive layer of the moisture-absorbing film is preferably made of an acrylic thermoplastic elastomer, more preferably an acrylic thermoplastic elastomer as a main component and a rosin tackifier. Furthermore, the thickness of the adhesive layer of the hygroscopic film is preferably 5 to 20 μm.

  According to the present invention, a hygroscopic laminate having a function of suppressing or delaying moisture absorption in the initial stage after production, and capable of exhibiting original moisture absorption performance as necessary, by adopting the above configuration. It became possible to realize. Therefore, in the hygroscopic laminate of the present invention, it is possible to suppress the moisture absorption of the film at each stage such as production, distribution, storage, and sales, and to have a trigger function for controlling the timing of starting the moisture absorption. Thus, it is possible to always obtain good adsorption performance during actual use.

It is typical sectional drawing which shows one structural example of the hygroscopic laminated body of this invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the present invention, the following description shows an example of the embodiment, and it goes without saying that the present invention is not limited thereto.
In FIG. 1, typical sectional drawing which shows the example of 1 structure of the hygroscopic laminated body of this invention is shown. As shown in the figure, the hygroscopic laminate 10 of the present invention comprises a hygroscopic film 1 and a pair of release films 2 sandwiching the hygroscopic film 1.

  In the present invention, the moisture-absorbing film 1 comprises a moisture-absorbing layer 3 made of a binder resin and a moisture-adsorbing substance, and one or both surfaces thereof, in the illustrated example, an adhesive layer 4 provided on one surface. It consists of a release layer 6 made of a polyolefin resin and a support layer 5. In the present invention, with such a configuration, the moisture absorbing film 1 having moisture absorbing performance is sandwiched between the pair of release films 2, and the moisture absorbent film 1 and the release film 2 are combined with the moisture absorbent layer 3 or the adhesive layer 4 and the release layer 6. In the initial state, the moisture absorption performance of the moisture absorbent film 1 can be suppressed by the release film 2.

  In the present invention, the release layer 6 of the release film 2 is formed from a cyclic polyolefin resin. Of the release film 2, the contact surface of the moisture-absorbing film 1 with the moisture-absorbing layer 3 or the adhesive layer 4 is required to have good peelability from the moisture-absorbing layer 3 and the adhesive layer 4, and the release film 2 is peeled off. In order to provide the function of exhibiting the original hygroscopic performance from the time, sufficient water vapor barrier properties in the state before peeling are required. In the present invention, the release layer 6 is formed using a cyclic polyolefin resin having high moisture resistance as a material that satisfies these required performances, thereby ensuring moisture absorption performance in the initial state. Thus, it is possible to realize the hygroscopic laminate 10 that can start absorbing moisture by peeling off the isolation film 2. In particular, the release layer 6 made of the cyclic polyolefin resin according to the present invention has good peelability when an acrylic resin is used for the moisture absorption layer 3 and the adhesive layer 4.

  Since the release layer 6 made of the cyclic polyolefin resin is a thin layer, a single layer is difficult to grip and is difficult to peel. Therefore, in the present invention, as the support layer 5 for peeling, a relatively inexpensive resin having adhesiveness at the time of co-extrusion with the cyclic polyolefin resin is laminated on the release layer 6 to release the film 2. Is forming. The resin used for the support layer 5 is preferably a polyethylene resin, and in particular, a linear low-density polyethylene resin or a low-density polyethylene resin having good adhesion to a cyclic polyolefin resin and good film-forming properties. Is preferably used.

  The thickness of the release layer 6 made of a cyclic polyolefin resin is preferably 5 to 20 μm, more preferably 5 to 10 μm. If the thickness of the release layer 6 is less than the above range, moisture resistance may be insufficient, and film-forming properties by coextrusion are deteriorated. On the other hand, if the thickness of the release layer 6 exceeds the above range, the cost increases. Moreover, it is preferable that the thickness of the support layer 5 is 25-60 micrometers, More preferably, it is 30-50 micrometers. If the thickness of the support layer 5 is less than the above range, the handling property (ease of gripping) of the film is not sufficiently improved, and if it exceeds the above range, the cost increases.

  Next, the moisture absorption layer 3 which comprises the moisture absorption film 1 consists of binder resin and a moisture absorptive substance. It does not specifically limit as binder resin used for the moisture absorption layer 3, For example, an acrylic thermoplastic elastomer, a styrene thermoplastic elastomer, etc. can be mentioned. In particular, the moisture absorption material can be highly filled, the physical properties of the hygroscopic film 1 such as pinhole resistance, puncture strength, and stiffness (flexibility) are maintained, and the release layer 6 of the release film 2 It is preferable to use an acrylic thermoplastic elastomer from the viewpoints of good releasability from the cyclic polyolefin resin that constitutes and no delamination between the adhesive layer 4 and the like. Moreover, when using a styrene-type thermoplastic elastomer as binder resin, in order to improve adhesiveness with an acrylic adhesive, it is preferable to perform pretreatments, such as a corona treatment, before application | coating of an adhesive. In addition, it is preferable that the moisture permeability of binder resin is high from a viewpoint of improving the initial hygroscopicity after peeling of the peeling film 2, and an acrylic thermoplastic elastomer is used suitably also from this point. Further, considering that the melt viscosity increases when the moisture-adsorbing substance is kneaded, the MFR of the binder resin measured under the conditions of a temperature of 190 ° C. and a load of 2.16 kg is preferably 5 to 40 g / 10 min. More preferably, it is 15-35 g / 10min. When the MFR value is smaller than the above range, it becomes difficult to extrude the resin due to an increase in melt viscosity when the moisture adsorbing substance is kneaded. On the other hand, when the MFR value exceeds the above range, the melt viscosity of the hygroscopic layer is lowered, and the film forming property is lowered.

  Further, as the moisture-adsorbing substance used for the moisture-absorbing layer 3, a chemically-adsorbing substance that has no re-wetting property and maintains a solid shape even after absorbing moisture can be suitably used. Specific examples include alkali metal oxides, alkaline earth metal oxides, sulfates, metal halides, perchloric acid, and organic substances.

Among these, examples of the alkali metal oxide include sodium oxide (Na ₂ O) and potassium oxide (K ₂ O). Examples of the alkaline earth metal oxide include calcium oxide (CaO) and magnesium oxide ( MgO), barium oxide (BaO), and the like. As sulfates, calcium sulfate (CaSO ₄ ), magnesium sulfate (MgSO ₄ ), lithium sulfate (Li ₂ SO ₄ ), sodium sulfate (Na ₂ SO ₄ ), cobalt sulfate (CoSO ₄ ), gallium sulfate (Ga) ₂ (SO ₄ ) ₃ ), titanium sulfate (Ti (SO ₄ ) ₂ ), nickel sulfate (NiSO ₄ ), and the like, and anhydrous salts are particularly preferable.

Further, as metal halides, calcium chloride (CaCl ₂ ), magnesium chloride (MgCl ₂ ), strontium chloride (SrCl ₂ ), yttrium chloride (YCl ₃ ), copper chloride (CuCl ₂ ), calcium bromide (CaBr ₂ ) , Cerium bromide (CeBr ₃ ), selenium bromide (SeBr ₄ ), vanadium bromide (VBr ₂ ), magnesium bromide (MgBr ₂ ), cesium fluoride (CsF), tantalum fluoride (TaF ₅ ), fluoride niobium _(NbF 5), barium iodide _(BaI 2), there may be mentioned such as magnesium iodide (MgI _2), in particular is suitable anhydrous salt. Furthermore, examples of perchlorate include magnesium perchlorate (Mg (ClO ₄ ) ₂ ), barium perchlorate (Ba (ClO ₄ ) ₂ ) and the like, and anhydrous salts are particularly preferred. . Even when an organic substance is used as the chemically adsorbing substance, it is necessary to chemically adsorb moisture and maintain a solid state even when moisture is absorbed.

  As a weight ratio of the binder resin and the moisture-adsorbing substance in the moisture-absorbing layer 3, in order to ensure high moisture-absorbing performance of the moisture-absorbing layer 3, the moisture-adsorbing substance is used in an amount of 80 to 40 with respect to 20 to 60 parts by mass of the binder resin. It is preferable to mix by mass part. More preferably, the weight ratio is 70 to 30 parts by mass of the moisture-adsorbing substance with respect to 30 to 50 parts by mass of the binder resin. When the weight ratio of the binder resin is higher than the above range and the weight ratio of the moisture-adsorbing substance is low, sufficient moisture absorption performance may not be obtained. On the other hand, when the weight ratio of the binder resin is lower than the above range and the weight ratio of the moisture-adsorbing substance is high, the ratio of the moisture-adsorbing substance is increased, so that the melt viscosity becomes excessively high and the moldability decreases. End up. In addition, about the thickness of the moisture absorption layer 3, it does not specifically limit, It can determine with a use in the range of 25-300 micrometers.

  In the hygroscopic film 1, the adhesive layer 4 is provided on one side or both sides of the hygroscopic layer 3. A known pressure-sensitive adhesive can be used as a material for forming the pressure-sensitive adhesive layer 4 and is not particularly limited. Specific examples include pressure sensitive adhesives such as rubbers, silicones, and acrylics. In particular, maintenance of adhesiveness, delamination does not occur with the moisture absorption layer 3, releasability with the cyclic polyolefin resin constituting the release layer 6 of the release film 2 is good, coextrusion From the standpoint of film-forming property due to, it is preferable to use an acrylic thermoplastic elastomer. Among them, it is more preferable to use an acrylic thermoplastic elastomer having an MFR measured at a temperature of 190 ° C. and a load of 2.16 kg of 5 to 40 g / 10 min.

  Further, depending on the situation to be used, when higher adhesiveness is required, the material for forming the adhesive layer 4 is mainly composed of an acrylic thermoplastic elastomer, and as a subcomponent, as a tackifier. You may use what added a tackifier. As such a tackifier, a rosin-based tackifier is preferable from the viewpoint of compatibility with an acrylic resin.

  The thickness of the pressure-sensitive adhesive layer 4 is preferably 5 to 20 μm, more preferably 5 to 15 μm, from the viewpoint of maintaining adhesiveness. If the thickness is thinner than the above range, formation of the adhesive layer 4 is difficult, and sufficient adhesiveness may not be obtained. If the thickness exceeds the above range, the cost increases.

  The hygroscopic laminate 10 of the present invention uses a co-extrusion laminating method that can quickly produce various laminated films having different layer configurations, and does not require special equipment or facilities as in the past. Can be manufactured easily. The hygroscopic laminate of the present invention can be suitably used as a hygroscopic material in, for example, organic devices such as organic EL elements, electronic books, liquid crystal display devices, organic solar cells, and the like.

Hereinafter, the present invention will be described in more detail with reference to examples.
<Example 1>
In accordance with the following, the hygroscopic laminated body of the layer structure shown in FIG. 1 was produced.
As a material of the release layer 6 of the release film 2, 100 parts by weight of a cyclic olefin polymer resin (COP) (manufactured by Nippon Zeon Co., Ltd., ZEONOR 1020R, Tg = 102 ° C.) is used. Linear low-density polyethylene resin (M-LLDPE) obtained by a polymerization reaction using a metallocene catalyst (Prime Polymer Co., Ltd., Evolve SP2020, MFR = 2.3 (190 ° C., 2.16 kg)) 100 weight Parts were used.

  Also, 40 parts by mass of an acrylic thermoplastic elastomer (Kuraray Co., Ltd., LA polymer LA2250, MFR = 25 (190 ° C., 2.16 kg)) as a binder resin, and calcium oxide (CaO) as a moisture adsorbing substance 60 parts by mass was mixed and melt-kneaded using a single screw extruder, and resin pellets for forming the hygroscopic layer 3 were prepared using a granulator. On the other hand, 100 parts by mass of acrylic thermoplastic elastomer for forming the adhesive layer 4 (manufactured by Kuraray Co., Ltd., LA polymer LA2140e, MFR = 31 (190 ° C., 2.16 kg)) was used in a vacuum drier. Pre-dried at 5 ° C. for 5 hours.

  The hygroscopic laminate of Example 1 was produced at a total thickness of 120 μm by coextrusion of 6 layers using a multilayer T-die extruder using the material for forming each layer. The layer structure of this hygroscopic laminate was: support layer (30 μm) / release layer (10 μm) / hygroscopic layer (30 μm) / adhesive layer (10 μm) / release layer (10 μm) / support layer (30 μm). .

<Example 2>
Except for the layer structure, support layer (30 μm) / release layer (10 μm) / adhesive layer (10 μm) / moisture absorbing layer (30 μm) / adhesive layer (10 μm) / release layer (10 μm) / support layer (30 μm) Produced a hygroscopic laminate of Example 2 with a total thickness of 130 μm in the same manner as Example 1.

<Example 3>
As a material for forming the adhesive layer 4 of the moisture-absorbing film 1, 95 parts by mass of an acrylic thermoplastic elastomer (manufactured by Kuraray Co., Ltd., LA polymer LA2140e, MFR = 31 (190 ° C., 2.16 kg)), rosin tackifier (Arakawa Chemical Industries, Ltd., Superester A100, softening temperature 100 ° C.) Except for using a mixture of 5 parts by mass, the moisture absorption of Example 3 with a total thickness of 120 μm was the same as Example 1. A conductive laminate was produced. The layer structure of this hygroscopic laminate was: support layer (30 μm) / release layer (10 μm) / hygroscopic layer (30 μm) / adhesive layer (10 μm) / release layer (10 μm) / support layer (30 μm). .

<Example 4>
Low density polyethylene resin (LDPE) obtained by a polymerization reaction using a Ziegler-Natta catalyst as a material for the support layer 5 of the release film 2 (Nippon Polyethylene Co., Ltd., Novatec LC522, melting point 111 ° C., MFR = 4 ( A hygroscopic laminate of Example 4 was produced in the same manner as in Example 1 except that 190 ° C., 2.16 kg)) was used, with a total thickness of 120 μm. The layer structure of this hygroscopic laminate was: support layer (30 μm) / release layer (10 μm) / hygroscopic layer (30 μm) / adhesive layer (10 μm) / release layer (10 μm) / support layer (30 μm). .

<Example 5>
As a material for the support layer 5 of the release film 2, a low density polyethylene resin obtained by a polymerization reaction using a Ziegler-Natta catalyst (Nippon Polyethylene Co., Ltd., Novatec LC522, melting point 111 ° C., MFR = 4 (190 ° C., A hygroscopic laminate of Example 5 was produced in the same manner as Example 2 except that 2.16 kg)) was used, with a total thickness of 130 μm. The layer structure of the hygroscopic laminate is as follows: support layer (30 μm) / release layer (10 μm) / adhesive layer (10 μm) / hygroscopic layer (30 μm) / adhesive layer (10 μm) / release layer (10 μm) / support layer (30 μm).

<Comparative Example 1>
As a material for the release layer 6 of the release film 2, a linear low density polyethylene resin (M-LLDPE) obtained by a polymerization reaction using a metallocene catalyst (manufactured by Prime Polymer Co., Ltd., Evolue SP2020, MFR = 2. 3 (190 ° C., 2.16 kg)) A hygroscopic laminate of Comparative Example 1 was produced in the same manner as in Example 1 except that 100 parts by weight were used, with a total thickness of 120 μm. The layer structure of this hygroscopic laminate was: support layer (30 μm) / release layer (10 μm) / hygroscopic layer (30 μm) / adhesive layer (10 μm) / release layer (10 μm) / support layer (30 μm). .

<Comparative example 2>
A hygroscopic laminate of Comparative Example 2 was produced in the same manner as in Example 1 except that the release layer 6 was not provided on the release film 2 with a total thickness of 100 μm. The layer structure of this hygroscopic laminate was: support layer (30 μm) / moisture absorption layer (30 μm) / adhesive layer (10 μm) / support layer (30 μm)).

<Comparative Example 3>
In the same manner as in Example 1 except that the weight ratio of the binder resin and the moisture-adsorbing substance in the moisture-absorbing layer 3 was changed to binder resin: moisture-adsorbing substance = 100: 0, and the total thickness was 120 μm. A hygroscopic laminate was produced. The layer structure of this hygroscopic laminate was: support layer (30 μm) / release layer (10 μm) / hygroscopic layer (30 μm) / adhesive layer (10 μm) / release layer (10 μm) / support layer (30 μm). .

  Table 1 below shows the conditions of the hygroscopic laminate in each of the above Examples and Comparative Examples.

＊１）バインダ樹脂：アクリルエラストマー
＊２）水分吸着性物質：ＣａＯ

* 1) Binder resin: Acrylic elastomer * 2) Moisture-absorbing substance: CaO

<Evaluation test>
(1) Change in weight immediately after production For samples with dimensions of 10 × 10 cm of the hygroscopic laminate produced in Examples 1 to 5 and Comparative Examples 1 to 3, a constant temperature and humidity chamber immediately after production and at 25 ° C. and 75% RH The weight after standing for 1 day was measured, and the difference in weight was described as the amount of change.
(2) Change in weight after standing at room temperature for 3 days For samples of dimensions 10 × 10 cm of the hygroscopic laminate produced in Examples 1 to 5 and Comparative Examples 1 to 3, peeling after standing at room temperature for 3 days The layer was peeled off, and the change in weight was measured immediately after peeling and after standing in a constant temperature and humidity chamber at 25 ° C. and 75% RH for 10 days.
The above measurement results are shown in Table 2 below together with the moisture absorption state after peeling layer peeling after standing for 3 days at room temperature.

  As is clear from the results in Table 2 above, the hygroscopic laminates of Examples 1 to 5 had very little weight change when the release film was not peeled off, and had good moisture absorption after the release film was peeled off. Showed sex. On the other hand, in the hygroscopic laminates of Comparative Examples 1 and 2, moisture absorption had already started in a state where the release film was not peeled, and the trigger effect of the release film was not functioning. Further, in the hygroscopic laminate of Comparative Example 3, the hygroscopic layer did not contain a moisture adsorbing substance, and the hygroscopic capacity was not sufficient.

DESCRIPTION OF SYMBOLS 1 Hygroscopic film 2 Release film 3 Hygroscopic layer 4 Adhesive layer 5 Base material 6 Release layer 10 Hygroscopic laminated body

Claims (9)

A hygroscopic laminate comprising a hygroscopic film and a pair of release films sandwiching the hygroscopic film,
The moisture-absorbing film comprises a moisture-absorbing layer composed of a binder resin and a moisture-adsorbing substance, and an adhesive layer provided on one or both surfaces of the moisture-absorbing layer, and the release film is a release layer composed of a cyclic polyolefin resin; A hygroscopic material comprising a support layer, and the hygroscopic film and the release film are laminated by coextrusion between the hygroscopic layer or the adhesive layer and the release layer. Laminated body.   The hygroscopic laminate according to claim 1, wherein the support layer of the release film has a thickness of 25 to 60 μm and is made of a polyethylene resin.   The hygroscopic laminate according to claim 1 or 2, wherein the release layer of the release film has a thickness of 5 to 20 µm.   The binder resin of the moisture-absorbing layer of the moisture-absorbing film is an acrylic thermoplastic elastomer having an MFR of 5 to 40 g / 10 min measured at a temperature of 190 ° C and a load of 2.16 kg. The hygroscopic laminate according to one item.   The moisture-adsorbing substance of the moisture-absorbing layer of the moisture-absorbing film comprises at least one selected from the group consisting of alkali metal oxides, alkaline earth metal oxides, sulfates, metal halides, perchloric acid, and organic substances. The hygroscopic laminate according to any one of claims 1 to 4, which is a chemical moisture adsorbing substance.   The weight ratio of the binder resin and the moisture-adsorbing substance in the moisture-absorbing layer of the moisture-absorbing film is 80 to 40 parts by mass of the moisture-adsorbing substance with respect to 20 to 60 parts by mass of the binder resin. The hygroscopic laminate according to claim 1.   The hygroscopic laminate according to any one of claims 1 to 6, wherein the adhesive layer of the hygroscopic film is made of an acrylic thermoplastic elastomer.   The hygroscopic laminate according to any one of claims 1 to 7, wherein the adhesive layer of the hygroscopic film contains an acrylic thermoplastic elastomer as a main component and includes a rosin tackifier.   The thickness of the said adhesion layer of the said moisture absorption film is 5-20 micrometers, The hygroscopic laminated body as described in any one of Claims 1-8.

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