JP2011026521A - Hygroscopic and transparent film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hygroscopic and transparent film having a high transparency and excellent in drying capacity higher than those of conventional drying agents. <P>SOLUTION: This hygroscopic transparent film is provided by containing a (co)polymer (A) having a monomer expressed by general formula (1) as an essential constituting monomer. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a hygroscopic transparent film that absorbs moisture in a package of an electronic component comprising a hermetically sealed package. More specifically, the present invention relates to a transparent hygroscopic transparent film particularly useful for organic electroluminescence devices (hereinafter referred to as organic EL devices), inorganic electroluminescence (hereinafter referred to as inorganic EL devices), organic thin film solar cells, and the like.

As an electronic component including a hermetically sealed package, an organic EL device, an inorganic EL device, and the like can be given. These have a configuration in which a light emitting layer is sandwiched between a pair of electrodes. The light emitting layer is mainly composed of a fluorescent organic compound in an organic EL device, and is composed mainly of an inorganic phosphor in an inorganic EL device.
Organic EL devices and inorganic EL devices (hereinafter collectively referred to as EL devices) are sealed with a very small amount of moisture in a hermetically sealed package because a small amount of moisture adversely affects the characteristics. A desiccant that absorbs and removes is installed in a hermetically sealed package.

  The biggest problem with organic EL devices is to improve the lifetime of the light emitting part. The cause of the short lifetime is the occurrence of non-light emitting dots called dark spots. The non-light-emitting dots grow with the lighting elapsed time, and the non-light-emitting area gradually increases, and the light emission luminance of the light-emitting portion decreases. And if the diameter of a non-light-emitting part grows to several tens of micrometers or more, it will be able to confirm visually, and the lifetime as a product will be exhausted here. This dark spot is caused by the moisture contained in the organic EL layer constituting the organic EL device or the moisture contained in the atmosphere inside the hermetically sealed package or the hermetically sealed package. It is known to generate and grow by reacting with moisture entering the inside through the seal part from the outside.

  Therefore, it is necessary to reduce the moisture in the hermetically sealed package in which the organic EL device is installed as much as possible. In particular, it is important to purify the organic material used for the light-emitting portion to be free from moisture. In addition, in order to prevent moisture from remaining in the hermetically sealed package, the light emitting unit is covered inside the vacuum chamber used when forming the light emitting unit on the substrate or on the upper surface of the substrate on which the light emitting unit is formed. In a manufacturing process such as a sealing operation of a device to which a sealing cap is attached, an organic EL device is manufactured by a dry process by devising to remove moisture in the container as much as possible. However, in the current situation, moisture cannot be completely removed from the manufacturing process, and the generation and growth of dark spots are not completely eliminated.

  In this way, the biggest problem with organic EL devices is to eradicate dark spots by completely eliminating moisture in the container, or to prevent the growth of small dark spots, thereby extending the lifetime of the device. is there. As a countermeasure, a method is disclosed in which an inorganic desiccant such as barium oxide (BaO) or calcium oxide (CaO) is mixed in a water-permeable resin and a film-shaped desiccant is used (for example, patents). Reference 1). However, in this method, since the film is opaque, it can be used for the bottom emission method in which light of organic molecules is taken out from the bottom of the TFT substrate side. There is a problem that it cannot be used for the top emission method in which light is extracted from above the sealing glass side that is attracting attention from the viewpoint.

JP 2006-116501 A

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a hygroscopic transparent film having high transparency and superior drying ability compared to conventional desiccants.

［式中、Ｒ¹及びＲ²はそれぞれ独立に、水素原子、炭素数１〜２０の直鎖、分岐又は環状のアルキル基、炭素数６〜１５のアリール基、モノ又はポリエチレングリコールモノアルキルエーテルから水酸基を除いた炭素数３〜２０の基及び炭素数１〜２０のアシル基からなる群から選ばれる原子又は置換基であり、置換基の場合その置換基の水素原子の少なくとも１つがハロゲン原子で置換されていてもよく、Ｍは３価の金属原子である。］ As a result of intensive studies to achieve the above object, the present inventors have reached the present invention. That is, the present invention
A hygroscopic transparent film comprising the (co) polymer (A) having the monomer represented by the general formula (1) as an essential constituent monomer; the hygroscopic transparent film and the light emitting layer An organic light-emitting element comprising an airtightly sealed package and an airtightly sealed package in which the hygroscopic transparent film and the active layer are disposed It is a battery.

[Wherein, R ¹ and R ² are each independently a hydrogen atom, a linear, branched or cyclic alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 15 carbon atoms, a mono- or polyethylene glycol monoalkyl ether. It is an atom or substituent selected from the group consisting of a group having 3 to 20 carbon atoms excluding a hydroxyl group and an acyl group having 1 to 20 carbon atoms. In the case of a substituent, at least one hydrogen atom of the substituent is a halogen atom. It may be substituted and M is a trivalent metal atom. ]

  The hygroscopic transparent film of the present invention is excellent in transparency and drying ability. Therefore, the hygroscopic transparent film of the present invention is particularly useful for the use of a desiccant that requires light transmission. For example, when used in a top emission type organic EL device, the lifetime can be greatly improved.

  The hygroscopic transparent film of the present invention is characterized by containing a (co) polymer (A) having the monomer represented by the general formula (1) as an essential constituent monomer.

R ¹ and R ² in the general formula (1) are each independently a hydrogen atom, a linear, branched or cyclic alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 15 carbon atoms, mono- or polyethylene glycol monoalkyl. An atom or a substituent selected from the group consisting of a group having 3 to 20 carbon atoms and an acyl group having 1 to 20 carbon atoms excluding a hydroxyl group from ether, and in the case of a substituent, at least one hydrogen atom of the substituent is a halogen atom It may be substituted with an atom.

  Examples of the linear, branched or cyclic alkyl group having 1 to 20 carbon atoms include methyl group, ethyl group, n- or iso-propyl group, n-, iso-, sec- or tert-butyl group, n- or iso. -Pentyl group, cyclopentyl group, n- or iso-hexyl group, cyclohexyl group, n- or iso-heptyl group, n- or iso-octyl group, 2-ethylhexyl group, n- or iso-nonyl group, n- or iso-decyl, n- or iso-dodecyl, n- or iso-tridecyl, n- or iso-tetradecyl, n- or iso-hexadecyl, n- or iso-stearyl, n-nonadecyl and Examples include an n-eicosyl group.

  Examples of the aryl group having 6 to 20 carbon atoms include phenyl group, tolyl group, xylyl group, cumenyl group, mesityl group, naphthyl group, anthryl group, phenanthryl group and pyrenyl group.

  Examples of the group having 3 to 20 carbon atoms obtained by removing a hydroxyl group from mono- or polyethylene glycol monoalkyl ether include groups obtained by removing a hydroxyl group from ethylene glycol monomethyl ether, diethylene glycol monomethyl ether, triethylene glycol monomethyl ether, and the like.

  Examples of the acyl group having 1 to 20 carbon atoms include formyl group, acetyl group, propionyl group, n- or iso-butynyl group, n- or iso-valeryl group, pivaloyl group, lauroyl group, myristoyl group, palmitoyl group and stearoyl group Etc.

In addition, as a substituent in which at least one of the hydrogen atoms of these substituents is substituted with a halogen atom,
A trifluoromethyl group, a pentafluoroethyl group, etc. are mentioned.

  Among these, from the viewpoint of physical adsorption of moisture, a group having 3 to 20 carbon atoms in which a hydroxyl group is removed from mono- or polyethylene glycol monoalkyl ether is preferable, and more preferable is an alkyl having 1 to 12 carbon atoms. A group obtained by removing a hydroxyl group from ethylene glycol monoalkyl ether, diethylene glycol monoalkyl ether or triethylene glycol monoalkyl ether.

  M in the general formula (1) is a trivalent metal atom, and specifically includes aluminum, gallium, indium, thallium, and the like. Aluminum is preferable from the viewpoint of reactivity with moisture and cost.

Although the manufacturing method of the monomer shown by General formula (1) is not specifically limited, For example, when M is aluminum, it can manufacture with the following method.
In a nitrogen atmosphere, trialkylaluminum is dissolved in a solvent, methacrylic acid is added dropwise in an equimolar amount with respect to trialkylaluminum, and then R ¹ OH and R ² OH [R ¹ and R ² are in the general formula (1). R ¹ and R ² are the same. ] Can be obtained by dropping equimolar amounts of trialkylaluminum at the same time or separately, respectively, to obtain a monomer represented by the general formula (1).

  The (co) polymer (A) contained in the hygroscopic transparent film of the present invention contains the monomer represented by the general formula (1) as an essential constituent monomer, but does not impair the transparency and drying ability. Thus, other monomers can be used in combination.

Other monomers include alkyl (meth) acrylates having 1 to 20 carbon atoms in the alkyl group [methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, etc. ] Etc. are mentioned.
Of these, alkyl (meth) acrylates having 1 to 4 carbon atoms are preferred from the viewpoint of transparency, and methyl methacrylate is more preferred.

  The proportion of the monomer represented by the general formula (1) in all monomers constituting the (co) polymer (A) is preferably 20 to 100 mol% from the viewpoint of transparency and drying ability. More preferably, it is 40 to 100 mol%.

  The number average molecular weight of the (co) polymer (A) is not particularly limited, but the number average molecular weight is preferably 3,000 to 500,000, more preferably from the viewpoint of the flexibility and strength of the film. 10,000 to 200,000. The number average molecular weight in the present invention can be measured by gel permeation chromatography (GPC) using polystyrene as a standard substance.

The (co) polymer (A) can be produced by a known polymerization method using the monomer and a radical polymerization initiator.
The polymerization temperature is usually 10 to 200 ° C., preferably 40 to 180 ° C., and the polymerization time is usually 1 to 48 hours, preferably 4 to 24 hours.

As radical polymerization initiators, those which generate free radicals to initiate polymerization, such as 2,2′-azobisisobutyronitrile (AIBN) and 2,2′-azobis- (2,4-dimethylvalero), are used. Nitriles) (AVN) and other azo compounds and peroxides such as dibenzoyl peroxide, dicumyl peroxide, persulfate, perborate and persuccinic acid.
The usage-amount of a polymerization initiator is 0.01-20 weight% based on the whole quantity of a monomer, Preferably it is 0.05-10 weight%.

  At the time of polymerization, hydrocarbon solvents (toluene, xylene, hexane, etc.), ester solvents (ethyl acetate, butyl acetate, etc.) and ketone solvents (acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.) can be used.

  The hygroscopic transparent film of the present invention may consist only of the (co) polymer (A), but in order to impart film formability, uniformity and adhesion to the substrate, an acrylic resin, a polycarbonate resin Resins such as polyester resin, epoxy resin, ketone resin, polyamide resin and polyether resin can be used in combination as long as transparency and drying ability are not impaired.

  The (co) polymer (A) and, if necessary, a mixture of the above resins can be formed into a film by a known method such as a melt extrusion method or a solvent casting method.

  An electroluminescent device obtained by installing the hygroscopic transparent film and the light emitting layer of the present invention in a package and hermetically sealed, and the hygroscopic transparent film of the present invention and an active layer of the present invention are installed in a package and hermetically sealed. The organic thin film solar cell obtained by the present invention is excellent in performance such as luminance and power storage, and can have a long life. Therefore, the hygroscopic transparent film of the present invention is extremely effective for organic EL devices, inorganic EL devices, organic thin film solar cells, It is.

  Hereinafter, although an example and a comparative example explain the present invention further, the present invention is not limited to these. Hereinafter, unless otherwise specified, parts are parts by weight.

Example 1
In a nitrogen atmosphere at room temperature, 13 parts of trimethylaluminum and 100 parts of hexane were uniformly dissolved. After stirring, 59 parts of triethylene glycol monomethyl ether was stirred and the temperature was controlled at 25 ± 5 ° C. over 15 minutes. It was dripped. Next, under stirring, 15.5 parts of methacrylic acid was added dropwise over 15 minutes while controlling the temperature at 25 ± 5 ° C. to obtain a monomer solution (1).
In a separate reaction vessel, 90 parts of toluene was charged, and the temperature was raised to 70 ° C., and then a solution of 0.49 part of 2,2′-azobisisobutyronitrile in 10 parts of toluene and the monomer solution (1) The whole amount was dropped and polymerized over 5 hours while maintaining the temperature at 70 ± 3 ° C. with stirring to obtain a polymer (A-1) solution.
The polymer (A-1) solution obtained was cast on a release paper so that the dry film thickness was 200 μm, and dried at room temperature under no water (in a glove box) for 10 hours. A film of A-1) was obtained. The number average molecular weight of the polymer (A-1) was 12,000.

Example 2
In a nitrogen atmosphere at room temperature, 6.5 parts of trimethylaluminum and 100 parts of hexane were charged and dissolved uniformly. Then, 29 parts of triethylene glycol monomethyl ether was stirred and the temperature was controlled at 25 ± 5 ° C. for 15 minutes. It was dripped over. Next, under stirring, 7.8 parts of methacrylic acid was added dropwise over 15 minutes while controlling the temperature at 25 ± 5 ° C. to obtain a monomer solution (2).
In a separate reaction vessel, 90 parts of toluene was charged and the temperature was raised to 70 ° C., and then a solution in which 0.49 part of 2,2′-azobisisobutyronitrile was dissolved in 10 parts of toluene and the monomer solution (2 ) A monomer solution in which the total amount and 8 parts of methyl methacrylate are mixed together is dropped and polymerized over 5 hours while maintaining the temperature at 70 ± 3 ° C. with stirring, thereby copolymer (A- A solution of 2) was obtained.
The solution of the obtained copolymer (A-2) was cast on a release paper so that the dry film thickness was 200 μm, and dried for 10 hours at room temperature in water-free (in a glove box). A film of coalescence (A-2) was obtained. The number average molecular weight of the copolymer (A-2) was 7,000.

Comparative Example 1
50 parts of calcium oxide and 50 parts of low density polyethylene were kneaded and a film (B-1) having a thickness of 200 μm was obtained by a melt extrusion method.

  Table 1 shows the results obtained by measuring and evaluating the total light transmittance and the moisture absorption amount of the films obtained in Examples 1 and 2 and Comparative Example 1 by the method described below.

<Measurement method of total light transmittance>
Based on JIS K 7105 (plastic optical property test method), the total light transmittance of a sample film of 5 cm square was measured with an integrating sphere type light transmittance measuring device (1001DP manufactured by Nippon Denshoku Industries Co., Ltd.).

<Measurement method of moisture absorption>
The film was cut into dimensions of 100 mm in length and 100 mm in width and allowed to stand for 240 hours in an environment of a temperature of 25 ° C. and a humidity of 50% RH, and the moisture absorption rate and the saturated water absorption were determined from the change in the weight of the film.
The amount of moisture absorbed after 1 hour was defined as the rate of moisture absorption (mg / hr), and the amount of moisture absorbed when there was no increase in the amount of moisture absorbed until 240 hours was defined as the saturated amount of moisture absorbed (mg).
Moreover, it measured similarly about the moisture absorption in a high temperature environment (85 degreeC).

  From the results in Table 1, it can be seen that the hygroscopic transparent films of Examples 1 and 2 are superior in transparency and hygroscopic performance as compared with the film of Comparative Example 1.

  Since the hygroscopic transparent film of the present invention is excellent in transparency and moisture absorption, it is useful as a desiccant in a package of an electronic component composed of a hermetically sealed package. In addition, the organic EL device, inorganic EL device or organic thin-film solar cell using the hygroscopic transparent film of the present invention can achieve a long lifetime without degrading the performance, and therefore the hygroscopic transparent film of the present invention also in these applications Is useful.

Claims (4)

A hygroscopic transparent film comprising a (co) polymer (A) having a monomer represented by the general formula (1) as an essential constituent monomer.

[Wherein, R ¹ and R ² are each independently a hydrogen atom, a linear, branched or cyclic alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 15 carbon atoms, a mono- or polyethylene glycol monoalkyl ether. It is an atom or substituent selected from the group consisting of a group having 3 to 20 carbon atoms excluding a hydroxyl group and an acyl group having 1 to 20 carbon atoms. In the case of a substituent, at least one hydrogen atom of the substituent is a halogen atom. It may be substituted and M is a trivalent metal atom. ]   The hygroscopic transparent film according to claim 1, wherein M is aluminum.   An electroluminescent element comprising a package in which the hygroscopic transparent film according to claim 1 or 2 and a light emitting layer are installed and hermetically sealed.   An organic thin film solar cell comprising a package in which the hygroscopic transparent film according to claim 1 or 2 and an active layer are installed and hermetically sealed.