KR-102963565-B1 - WHITE PIGMENT DISPERSION AND COMPOSITION FOR FORMING WHITE PARTITION WALL INCLUDING THE WHITE PIGMENT DISPERSION

Abstract

[Problem] The present invention provides a white pigment dispersion capable of forming a barrier of a display element having good reflectivity and a composition for forming a white barrier. [Solution] A white pigment dispersion comprising a white inorganic pigment, a polymeric dispersant, a dispersion aid, and a solvent, wherein the polymeric dispersant is an acid value type polymeric dispersant having a carboxyl group or a phosphate group, and the dispersion aid contains a compound having a phthalimide backbone as an active ingredient, and the phthalimide backbone may have a substituent directly connected to its carbon atom, and the nitrogen atom in the phthalimide backbone is connected to a group having a carboxyl group or a group having a nitrogen-containing six-membered ring quaternary ammonium cation.

Inventors

• 후쿠나가 마리

Assignees

• 산요 시키소 가부시키가이샤

Dates

Publication Date

20260511

Application Date

20220113

Priority Date

20210122

Claims (8)

1. A white pigment dispersion comprising a white inorganic pigment, a polymeric dispersant, a dispersion aid, and a solvent, The above polymeric dispersant comprises only acid value type polymeric dispersant having a carboxyl group or a phosphate group having an amine value of 0 mgKOH/g, and The above dispersion aid contains a compound having a phthalimide backbone as an active ingredient, and A white pigment dispersion in which the compound having the above-mentioned phthalimide skeleton is at least one selected from the compound represented by the following formula (1), or at least one selected from the compound represented by the following formula (3): (In Formula (1), R1 to R4 independently represent a hydrogen atom, a halogen atom, an alkyl group, or an aromatic hydrocarbon group, and X represents a divalent saturated hydrocarbon group that may have a substituent or a group represented by Formula (2) below. In Formula (2), "*" indicates the number of bonds.) (In formula (3), R1 to R4 independently represent a hydrogen atom, a halogen atom, an alkyl group, or an aromatic hydrocarbon group, and A represents a group having a nitrogen-containing six-membered ring quaternary ammonium cation.)
2. A white barrier-forming composition comprising a white pigment dispersion described in claim 1 and a white barrier-forming component.
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Description

White pigment dispersion and composition for forming a white partition wall including the same The present invention relates to a white pigment dispersion and a composition for forming a white barrier comprising the same. For example, in a display panel using display elements such as micro light-emitting diode (LED) elements or organic electroluminescence (organic EL) elements, a fine pattern partitioned by barriers to suppress light mixing is formed, and a light-emitting part is installed between the barriers. Such barriers are formed, for example, by a resin composition. And, as a composition capable of constituting such a resin composition, a colored composition having opacity, reflectivity, etc., to suppress light mixing is proposed (Patent Document 1). Patent Document 1 describes a negative-type photosensitive coloring composition comprising (A) a white pigment, (B) a siloxane resin, (C) a photopolymerization initiator, (D) a photopolymerizable compound, and (E) an organic solvent, wherein the siloxane resin (B) comprises structural units derived from a fluorine-containing alkoxysilane compound and structural units derived from a bifunctional alkoxysilane compound, and wherein these units are included in a predetermined amount. Furthermore, it is stated that, by this composition, a thick cured film with high reflectivity, high resolution, and excellent heat resistance can be formed. Figure 1 (a) is a drawing showing an image of Example 1, and (b) is a drawing showing an image of Comparative Example 3. A white pigment dispersion according to an embodiment of the present invention comprises a white inorganic pigment, a polymeric dispersant, a dispersion aid, and a solvent. The polymeric dispersant is an acid value type polymeric dispersant having a carboxyl group or a phosphate group. The dispersion aid contains a compound having a phthalimide backbone as an active ingredient. Furthermore, the phthalimide backbone may have a substituent directly connected to its carbon atom, and additionally, a group having a carboxyl group or a group having a nitrogen-containing six-membered ring quaternary ammonium cation is connected to the nitrogen atom in the phthalimide backbone. It is believed that by including the aforementioned specific acid value-type polymer-based dispersant and specific dispersion aid, this white pigment dispersion not only improves the dispersion state within the dispersion but also maintains a good dispersion state within the coating film or barrier. As the dispersion state in the coating film improves, the surface of the coating film is smoothed to reflect more light. In addition, it is believed that the reflectance can be improved by reflecting light transmitted by the titanium oxide on the surface, which is uniformly present within the coating film. As a result, it is believed that the reflectance of the barrier obtained using this is improved. The above-mentioned white inorganic pigment is not particularly limited as long as it is capable of concealing or reflecting light emitted from a light-emitting part. Examples include alumina, magnesium oxide, antimony oxide, titanium oxide, zirconium oxide, aluminum hydroxide, magnesium hydroxide, barium sulfate, magnesium carbonate, barium carbonate, calcium carbonate, lead sulfate, lead phosphate, zinc phosphate, silicon dioxide, zinc oxide, tin oxide, strontium sulfide, strontium titanate, barium titanate, barium tungstate, calcium silicate, aluminum silicate, lead metasilicate, talc, mica, kaolin, clay, bismuth chloride, hollow silica particles, etc. Among these, alumina, magnesium oxide, antimony oxide, titanium oxide, zirconium oxide, aluminum hydroxide, magnesium hydroxide, barium sulfate, magnesium carbonate, and barium carbonate are preferred, and titanium oxide is particularly preferred. These white inorganic pigments may be included in one type or in two or more types. Titanium oxide may be of the anatase or rutile type, but the rutile type is preferred. White inorganic pigments may be surface-treated. Examples of such surface treatments include inorganic compounds such as (hydrated) alumina, silica (high-density silica, porous silica), and zirconia, or organic compounds such as fatty acids, silicon, polyols, and amines, and combinations thereof. In terms of reflectance and coloring power, it is preferable that the average primary particle diameter of the white inorganic pigment be 100 to 400 nm. The average primary particle diameter can be measured, for example, by a transmission electron microscope JEM-1011 manufactured by Nihon Denshi Corporation. The content of the white inorganic pigment is preferably 50 to 80 weight percent of the white pigment dispersion. The polymeric dispersant may be an acid value type polymeric dispersant having a carboxyl group or a phosphate group (hereinafter referred to as an "acid group"). For example, a polymeric dispersant containing a polymer having a carboxyl group or a phosphate group in a side cha