JP6523780B2 - Film-forming composition and method for producing cured film using the same - Google Patents

Description

  The present invention relates to a film-forming composition and a method for producing a cured film using the same.

  Conventionally, a sealing element for sealing a display element such as an organic EL element or a liquid crystal display element included in a display device, or a light emitting diode (LED) included in an optical semiconductor device, a solar cell element, a CCD, a CMOS As materials, those containing an epoxy compound, a silicone resin, and a cyclic olefin resin are known (see Patent Documents 1 to 3 and the like).

JP, 2011-174023, A JP, 2011-063686, A JP, 2012-209375, A

  Although various properties are required for such a sealing material, the sealing material has a temperature as low as 200 ° C. or less so that thermal damage to optical devices such as display elements and optical semiconductor elements is suppressed. It is required that the composition can be cured to form a thick and uniform cured film. In addition, the sealing agent is also required to suppress outgassing so as not to degrade the performance of such an optical device.

  The present invention has been made in view of such conventional circumstances, and a film-forming composition which cures even at a low temperature of 200 ° C. or less and gives a cured film in which degassing is suppressed, and cure using the same It is an object to provide a method of producing a coating.

  The present inventors have intensively researched to solve the above-mentioned problems. As a result, it has been found that the above-mentioned problems can be solved by combining a specific polysiloxane having a branched structure with a thermal acid generator which is a quaternary ammonium salt, and the present invention has been accomplished. Specifically, the present invention provides the following.

（式中、Ｒ^１はエポキシ基又はオキセタニル基を含有する基であり、Ｒ^２はアルキル基又はアリール基であり、添え字ｍ及びｎは、上記ポリシロキサン中の全構造単位に対する上記添え字が付された構造単位のモル百分率を表し、ｍは５０〜９０モル％であり、ｎは１０〜５０モル％であり、ただし、ｍ及びｎの合計は１００モル％である。） A first aspect of the present invention is a film-forming composition comprising a polysiloxane represented by the following general formula (a1) and a thermal acid generator which is a quaternary ammonium salt.

(Wherein, R ¹ is a group containing an epoxy group or an oxetanyl group, R ² is an alkyl group or an aryl group, and the subscripts m and n indicate the above subscripts to all structural units in the above polysiloxane. Represents the mole percentage of the structural unit attached, m is 50 to 90 mol%, n is 10 to 50 mol%, provided that the total of m and n is 100 mol%)

  A second aspect of the present invention is a method of producing a cured film comprising a composition layer forming step of forming a composition layer consisting of the above film-forming composition on a substrate, and a heating step of heating the above composition layer. It is a method.

  According to the present invention, it is possible to provide a film-forming composition which cures even at a low temperature of 200 ° C. or less to give a cured film in which degassing is suppressed, and a method of producing a cured film using the same.

FIG. 1A to FIG. 1D are process cross-sectional schematic views for explaining the method for producing a cured film according to the embodiment of the present invention.

<Film-forming composition>
The film-forming composition according to the present invention contains the polysiloxane represented by the above general formula (a1) and a thermal acid generator which is a quaternary ammonium salt. The film-forming composition according to the present invention cures even at a low temperature of 200 ° C. or less to give a cured film in which degassing is suppressed. The film-forming composition according to the present invention is a display element such as an organic EL element or a liquid crystal display element included in a display device, or a light semiconductor such as a light emitting diode (LED) included in an optical semiconductor device, a solar cell element, a CCD, or CMOS It can be used suitably for sealing of an element.

[Polysiloxane Represented by General Formula (a1)]
The film-forming composition according to the present invention contains a polysiloxane represented by the above general formula (a1). The said polysiloxane can be used individually or in combination of 2 or more types.

In the above general formula (a1), R ¹ is a group containing an epoxy group or an oxetanyl group, preferably a group containing an epoxy group or an oxetanyl group at the end, more preferably a glycidoxyalkyl group, 3 —Oxetanylmethyloxyalkyl group, or 3-alkyl-3-oxetanylmethyloxyalkyl group (herein, examples of the alkyl group include alkyl groups having 1 to 6 carbon atoms, and specific examples thereof include R Groups exemplified for ² ), more preferably glycidoxypropyl group, 3-oxetanylmethyloxypropyl group, or 3-ethyl-3-oxetanylmethyloxypropyl group, and particularly preferably glycidoxypropyl group. It is a cidoxypropyl group. When a plurality of R ^{1 s} are present in the general formula (a1), these R ^{1 s} may be the same as or different from each other.

In the above general formula (a1), R ² is an alkyl group or an aryl group, preferably an alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 15 carbon atoms, more preferably 1 to 4 carbon atoms Or an aryl group having 6 to 10 carbon atoms. Examples of the alkyl group R ² include methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, tert-butyl, pentyl, isopentyl, neopentyl and hexyl groups. Methyl and ethyl are preferred, and methyl is more preferred. Examples of R ² which is an aryl group include phenyl group, biphenyl group, fluorenyl group, naphthyl group, anthryl group, phenanthryl group and the like, preferably phenyl group and naphthyl group, more preferably phenyl group . In the general formula (a1), when a plurality of R ^{2 s} are present, these R ^{2 s} may be the same as or different from each other.

  In the above general formula (a1), the subscripts m and n represent the mole percentage of the structural unit to which the above subscript is added with respect to all the structural units in the above polysiloxane, and m is 50 to 90 mol%, n Is 10 to 50 mol%, provided that the sum of m and n is 100 mol%. It is preferable that m is 70 to 90 mol% and n is 10 to 30 mol%.

The mass average molecular weight of the polysiloxane represented by the above general formula (a1) is not particularly limited as long as the effects of the present invention are not impaired, and is preferably 1000 to 8000, more preferably 2000 to 4000. When the mass average molecular weight is in the above range, the resulting cured film is likely to be further inhibited from degassing.
In addition, in this specification, a mass mean molecular weight means the thing of standard polystyrene conversion measured by gel permeation chromatography (GPC).

  The polysiloxane represented by the above general formula (a1) is, for example, hydrolysed in the presence of an acid catalyst, water, and an organic solvent, and alkoxysilanes corresponding to the respective structural units to which the subscript m or n is added. And can be prepared by a method of dehydration condensation.

[Thermal acid generator which is quaternary ammonium salt]
The film-forming composition according to the present invention is excellent in curability at a low temperature by containing a thermal acid generator which is a quaternary ammonium salt. The thermal acid generators can be used alone or in combination of two or more.

  The thermal acid generator is not particularly limited, and a conventionally known one can be used, and one that generates an acid by heating at 200 ° C. or less is particularly preferable. Specific examples of the thermal acid generator include K-PURE (registered trademark) TAG-2678, K-PURE CXC-1614, K-PURE CXC-1612, K-PURE CXC-1733, K-PURE CXC-1821, K-PURE TAG-2700, K-PURE TAG-2689, K-PURE TAG-2690, K-PURE CXC-1738, K-PURE CXC-1802-60 (all are manufactured by King Industries).

  In the film-forming composition according to the present invention, the addition amount of the thermal acid generator to the polysiloxane represented by the general formula (a1) is preferably 0.1 to 10.0 mass%, 0 It is more preferable that it is 0.2-5.0 mass%. When the amount added is in the above range, the film-forming composition according to the present invention is likely to further improve the curability at a low temperature of 200 ° C. or less.

[Organic solvent]
The film-forming composition according to the present invention may contain an organic solvent. By including the organic solvent, it becomes easy to adjust the coatability of the film-forming composition and the film thickness of the cured film produced from the film-forming composition. The organic solvents can be used alone or in combination of two or more.

  The organic solvent is not particularly limited, but, for example, alcohols such as methanol, ethanol, isopropanol (IPA) and butanol; ketones such as acetone, diethyl ketone and methyl ethyl ketone; esters such as methyl acetate, ethyl acetate and butyl acetate Polyhydric alcohols such as propylene glycol, glycerin and dipropylene glycol; ethers such as dipropylene glycol dimethyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, propylene glycol dimethyl ether and propylene glycol diethyl ether; ethylene glycol monomethyl ether, ethylene glycol mono Ethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether Monoether glycols such as propylene glycol monopropyl ether, dipropylene glycol monomethyl ether and 3-methoxy-3-methyl-1-butanol (sorbite); cyclic ethers such as tetrahydrofuran and dioxane; propylene glycol monomethyl ether acetate ( And ether esters such as propylene glycol monoethyl ether acetate, 3-methoxybutyl acetate (MBA) and ethyl diglycol acetate (EDGAC).

  The solid content concentration of the film-forming composition according to the present invention is preferably 10 to 100% by mass, more preferably 50 to 100% by mass, and the film according to the present invention in the sense that no influence is exerted by the organic solvent. More preferably, the formable composition is solvent free.

[Surfactant]
The film-forming composition according to the present invention may contain a surfactant. By including the surfactant, the coatability, the planarity, and the spreadability of the film-forming composition can be easily improved, and the occurrence of the coating unevenness of the composition layer formed after the application tends to be reduced. As surfactants, conventionally known ones can be used, and silicone surfactants are preferred. The content of the surfactant is preferably in the range of 10 to 10000 mass ppm, more preferably 100 to 10000 mass ppm, and still more preferably 500 to 5000 mass ppm based on the whole film forming composition. The surfactant may be used alone or in combination of two or more.

[Other ingredients]
The film-forming composition according to the present invention contains, as necessary, additives such as known reactive diluents, surface conditioners, antifoaming agents, and curing regulators (curing inhibitors or curing accelerators). May be
When the film-forming composition according to the present invention contains a reactive diluent, it can be prepared as a solventless composition, that is, a composition not containing the organic solvent, and the effect of the organic solvent is effective. Can be reduced to

  The reactive diluent includes cationically polymerizable compounds such as cationically polymerizable monomers and cationically polymerizable oligomers. The cationically polymerizable compounds may be used alone or in combination of two or more.

  As a cationically polymerizable compound, the organic compound which has a cationically polymerizable group is mentioned. The cationically polymerizable group includes an epoxy group, an oxetanyl group and an oxolanyl group. The cationically polymerizable compound may be an organosilicon compound having a cationically polymerizable group, and examples thereof include an organosilane having a cationically polymerizable group, an organosiloxane oligomer having a cationically polymerizable group, and the like.

  In the film-forming composition according to the present invention, the addition amount of the reactive diluent to the polysiloxane represented by the general formula (a1) is preferably 0.1 to 400% by mass, and 1 to 100. More preferably, it is mass%. It is easy to adjust the coatability of a film formation composition, and the film thickness of the cured film manufactured from a film formation composition as the said addition amount is in the said range.

<Method of producing cured film>
The method for producing a cured film according to the present invention includes a composition layer forming step of forming a composition layer comprising the film forming composition according to the present invention on a substrate, and a heating step of heating the composition layer. . Hereinafter, with reference to FIG. 1 (A)-FIG.1 (D), the manufacturing method of a cured film is demonstrated. FIG. 1A to FIG. 1D are process cross-sectional schematic views for explaining the method for producing a cured film according to the embodiment of the present invention.

  First, as shown in FIG. 1A, a substrate 2 on which an optical device 1 is mounted is prepared. The optical device 1 is, for example, a display element such as an organic EL element or a liquid crystal display element, or a light semiconductor element such as a light emitting diode (LED), a solar cell element, a CCD, or a CMOS. The substrate 2 is, for example, a back surface side protective layer or the like. The substrate 2 may be a surface side protective layer or the like stacked on the light receiving surface side or the light emitting surface side of the optical device 1. In addition, a solar cell or the like may be mounted on the substrate 2.

  Next, as shown in FIG. 1B, the film-forming composition according to the present invention is applied to the surface of the substrate 2 on the side on which the optical device 1 is mounted, to form the composition layer 3. The method of applying the film-forming composition is not particularly limited, and any known method can be employed. Thereby, the optical device 1 is coated with the composition layer 3.

  Next, as shown in FIG. 1C, the substrate 2 on which the composition layer 3 is stacked is placed in a heating furnace 4 such as an electric furnace, and the composition layer 3 is heated. As a result, as shown in FIG. 1 (D), the film-forming composition is thermally cured to form a cured film 5 on the surface of the substrate 2. The optical device 1 is sealed by the cured film 5. The heating temperature is a temperature of 200 ° C. or less, preferably a temperature of 180 ° C. or less, and more preferably a temperature of 150 ° C. or less. The lower limit of the heating temperature is not particularly limited as long as the cured film 5 is formed, and is, for example, 80 ° C. or higher, preferably 90 ° C. or higher. The film-forming composition according to the present invention is cured even at a low temperature of 200 ° C. or less to give a cured film 5.

  The cured film 5 can be manufactured by the above steps. Degassing is suppressed in the cured film 5 manufactured in this manner.

  Hereinafter, the present invention will be described in detail by way of examples, but the present invention is not limited to these examples.

[Examples 1 to 8 and Comparative Examples 1 to 11]
(Preparation of a film forming composition)
As shown in Tables 1 to 4, predetermined amounts of a polymer, an acid generator, and optionally a binder were mixed in a solvent to prepare a film-forming composition having a solid content concentration of 50% by mass. Further, as shown in Table 5, predetermined amounts of a polymer, an acid generator and an additive were mixed to prepare a solvent-free film-forming composition. In addition, when using several polymer, mixed mass ratio was written together in the table | surface. In addition, for the polymer E, the ratio (m1 / n1) of the subscripts m1 and n1 is also shown in the table.
The details of each component in Tables 1 to 5 are as follows.

Polymer A: Polymer represented by the following formula

Polymer B: Polymer represented by the following formula

Polymer C: Polymer represented by the following formula

（式中、添え字ｍ１及びｎ１は、ポリマーＥ中の全構造単位に対する上記添え字が付された構造単位のモル百分率を表し、ｍ１＝５０〜９０モル％であり、ｎ１＝１０〜５０モル％であり、ただし、ｍ１及びｎ１の合計は１００モル％である。） Polymer D: Organic-inorganic hybrid resin (trade name: COMPOCELAN E 202 C, manufactured by Arakawa Chemical Industries, Ltd.)
Polymer E: Polymer represented by the following formula (weight average molecular weight: 3000)

(Wherein, subscripts m1 and n1 represent mole percentage of structural units with the above subscripts relative to all structural units in polymer E, m1 = 50 to 90 mol%, n1 = 10 to 50 mol %, Provided that the sum of m1 and n1 is 100 mol%)

（式中、添え字ｍ２、ｎ２、及びｎ３は、ポリマーＦ中の全構造単位に対する上記添え字が付された構造単位のモル百分率を表し、ｍ２＝５０モル％、ｎ２＝１モル％、ｎ３＝４９モル％である。） Polymer F: Polymer represented by the following formula (weight average molecular weight: 3000)

(Wherein, subscripts m 2, n 2 and n 3 represent mole percentage of structural units having the above-mentioned subscripts with respect to all structural units in polymer F, m 2 = 50 mol%, n 2 = 1 mol%, n 3 = 49 mol%)

  Polymer G: poly [(2-oxiranyl) -1,2-cyclohexanediol] 2-ethyl-2- (hydroxymethyl) -1,3-propanediol ether (wherein poly [(2-oxiranyl) -1,2] The ratio of -cyclohexanediol] residue to 2-ethyl-2- (hydroxymethyl) -1,3-propanediol residue is 3: 1)

Polymer H: a polymer represented by the following formula

Acid generator A: Photoacid generator represented by the following formula

Binder: Binder represented by the following formula

Acid generator C: K-PURE TAG-2678 (thermal acid generator, manufactured by King Industries)
Acid generator D: Thermal acid generator represented by the following formula

Acid generator E: Thermal acid generator represented by the following formula

Acid generator F: Thermal acid generator represented by the following formula

  Acid generator G: K-PURE CXC-1821 (thermal acid generator, manufactured by King Industries)

Solvent A: 3-Methoxybutyl Acetate Solvent B: Propylene Glycol Monopropyl Ether Solvent C: Propylene Glycol Monomethyl Ether Acetate Solvent D: Propylene Glycol Monomethyl Ether

Additive A (reactive diluent): X-22-163 (both-end epoxy modified silicone oil, manufactured by Shin-Etsu Chemical Co., Ltd.)
Additive B (reactive diluent): 1,4-cyclohexanedimethanol glycidyl ether Additive C (reactive diluent): pentaerythritol tetraglycidyl ether

(Production of cured film)
Thermosetting The prepared film forming composition was applied on a glass substrate to a final film thickness of 1.0 to 15.0 μm using a spin coater, a spinless coater, or a screen printing apparatus. Next, the sample was placed on a hot plate and prebaked at 80 to 200 ° C. for 5 to 120 minutes. Then, a vertical baking furnace (product name: TS8000MV, manufactured by Tokyo Ohka Kogyo Co., Ltd.) in _{N 2} at, by heating for 30 minutes at 80 to 200 ° C., is thermally cured to obtain a cured film.

-UV Curing The prepared film forming composition was applied on a glass substrate to a final film thickness of 1.0 to 15.0 μm using a spin coater, a spinless coater, or a screen printing apparatus. Next, the sample was placed on a hot plate and prebaked at 90 ° C. for 5 minutes. Thereafter, ghi rays were irradiated at an exposure amount of 999 J / m ² using an ultraviolet irradiation device (HMW-532D, manufactured by ORC). Finally, the sample was placed on a hot plate and subjected to PEB treatment at 90 to 200 ° C. for 5 minutes to obtain a cured film.

(Evaluation of residual film rate)
The obtained cured film was immersed in a solvent (acetone) for 60 minutes, and the thickness of the cured film after solvent immersion was measured using a surface shape measuring device (trade name: Dektak 3ST, manufactured by ULVAC, Inc.). The residual film ratio was calculated based on the thickness of the cured film before measurement, and was used as an index of low-temperature curing characteristics. Evaluation criteria are as follows. The results are shown in Tables 1-5.
○ (Good): Residual film rate 98% or more, ×: (Defective): Residual film rate less than 98%

(Weight loss evaluation)
About the obtained cured film, the differential thermal-thermogravimetry simultaneous measurement (TG-DTA) was performed using thermal-analysis apparatus TG8120 (brand name, RIGAKU company make). Based on the weight of the cured film before measurement, the weight loss at 100 ° C. was calculated and used as an index of degassing characteristics. The results are shown in Tables 1-5.

＊更に、バインダーＢを添加した。ポリマーに対するバインダーＢの添加量は１０．０％であった。

* Furthermore, binder B was added. The amount of binder B added to the polymer was 10.0%.

  As apparent from Tables 1 to 5, the film-forming composition of the example contains the polysiloxane represented by the above general formula (a1) and the thermal acid generator which is a quaternary ammonium salt. , It was excellent also in any residual film rate evaluation and weight loss evaluation. In contrast, the film-forming composition of the comparative example does not contain at least one of the polysiloxane represented by the general formula (a1) and the thermal acid generator which is a quaternary ammonium salt. , And was inferior in at least one of residual film rate evaluation and weight loss evaluation.

1 optical device 2 substrate 3 composition layer 4 heating furnace 5 cured film

Claims (4)

A film-forming composition for sealing a display element or an optical semiconductor element , which comprises a polysiloxane represented by the following general formula (a1) and a thermal acid generator which is a quaternary ammonium salt.

(Wherein, R ¹ is a group containing an epoxy group or an oxetanyl group, R ² is an alkyl group or an aryl group, and the subscripts m and n indicate the subscripts to all structural units in the polysiloxane. Represents the mole percentage of the structural unit attached, m is 50 to 90 mol%, n is 10 to 50 mol%, provided that the total of m and n is 100 mol%)   A film-forming composition containing a polysiloxane represented by the following general formula (a1), a thermal acid generator which is a quaternary ammonium salt, and a reactive diluent and does not contain an organic solvent.

(In the formula, R ¹ Is a group containing an epoxy group or an oxetanyl group, R ² Is an alkyl group or an aryl group, and the subscripts m and n represent the mole percentage of the structural unit with the above subscripts relative to the total structural units in the polysiloxane, and m is 50 to 90 mol% n is 10 to 50 mol%, provided that the sum of m and n is 100 mol%. ) A composition layer forming step of forming a composition layer consisting of the film forming composition according to claim 1 or 2 on a substrate,
And a heating step of heating the composition layer. The method according to claim 3 , wherein the heating temperature in the heating step is 200 ° C. or less.

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