JP4582439B2 - Silica-coated zinc oxide-containing powder, organic polymer composition containing the same, and molded article thereof - Google Patents

Description

また、シリカ被覆酸化亜鉛９７質量部にジメチルポリシロキサン（ＫＦ９６−１００ＣＳ 信越化学工業（株）製）３質量部の塩化メチレン溶解液を加え、ヘンシェルミキサー（三井三池鉱山（株）製）にて良く混合し、その後９０℃での真空乾燥により溶媒を除去した後、２００℃、６時間焼成することにより表面疎水化されたシリカ被覆酸化亜鉛を得た。得られたシリカ被覆酸化亜鉛含有粉末の５μｍ以上の粗粒の含有量は、１．６質量％であった。亜鉛イオンの溶出性については、結果を表２に示す。
【０１２１】
本発明のシリカ被覆酸化亜鉛は、各種ｐＨにおいて未被覆酸化亜鉛に比較し、亜鉛イオンの溶出が極めて抑制されており、純水中では０．５ｐｐｍ以下と極めて少なかった。更に表面疎水化することにより各種ｐＨにおける溶出性がいっそう抑制された。有機重合体組成物やその成型品においても、酸性あるいはアルカリ性溶液との接触による亜鉛イオンの溶出防止効果が充分期待できる。
【０１２２】
【表２】

さらにこの表面疎水化された粉末を、ターボクラシファイア（日清エンジニアリング株式会社製）を用いて乾式精密分級した。得られたシリカ被覆酸化亜鉛含有粉末の５μｍ以上の粗粒の含有量は、０．０２質量％であった。
【０１２３】
このようにして得られたシリカ被覆酸化亜鉛含有粉末２０部とポリプロピレン（サンアロマー（株）製ＰＷ６００Ｎ）８０部とを川田（株）製スーパーミキサーで６００ｒｐｍ、３分間混合した後、中谷（株）製３０ｍｍ異方向２軸押出機にて混練して有機重合体組成物マスターバッチを得た。
【０１２４】
得られた有機重合体組成物マスターバッチについて、２３０（入口）−２３０−２３０−２３０℃の温度条件で、ラボプラストミルによる成形性評価を行った。結果は表3に示す通り、樹脂圧上昇は１．３ＭＰａと低く、成形性は良好であった。
【０１２５】
得られた有機重合体組成物マスターバッチをサンアロマー（株）製ＰＷ６００Ｎで希釈して、光触媒作用による耐候劣化試験を行った。
【０１２６】
サンシャインスーパーロングライフウェザーメーターにかける前のフィルムのヘイズは１８．２、かけた後のフィルムのヘイズは１８．６と、ヘイズの変化は０．４と小さく、光触媒作用による耐候劣化は非常に少なかった。このことから、得られたシリカ被膜酸化亜鉛微粒子はポリプロピレンに対する光触媒による耐候劣化は非常に小さいことがわかる。
【０１２７】
実施例２：
実施例１において、ポリプロピレン（サンアロマー（株）製ＰＷ６００Ｎ）の替わりに、ポリエチレン（日本ポリオレフィン（株）製ＪＨ６０７Ｃ）を用いた以外は実施例１と同じ操作を行い、有機重合体組成物マスターバッチを得た。
【０１２８】
得られた有機重合体組成物マスターバッチについて、実施例１と同様にラボプラストミルによる成形性評価を行った結果、樹脂圧上昇は０．７ＭＰａと小さく、成形性は良好であった。
【０１２９】
また、ポリエチレン（日本ポリオレフィン（株）製ＪＨ６０７Ｃ）で希釈して、光触媒作用による耐候劣化試験を行った結果、ヘイズの変化は０．２と小さく、光触媒作用による耐候劣化は非常に少なかった。
このことから、得られたシリカ被膜酸化亜鉛微粒子はポリエチレンに対する光触媒による耐候劣化は非常に小さいことがわかる。
【０１３０】
実施例３：
実施例１において、ポリプロピレン（サンアロマー（株）製ＰＷ６００Ｎ）の替わりに、ポリアミド（エムス昭和電工(株)製、Ａ２８ＧＭ）を用いた以外は実施例１と同じ操作を行い、有機重合体組成物マスターバッチを得た。
【０１３１】
得られた有機重合体組成物マスターバッチについて、温度条件を２７０（入口）−２７０−２７０−２７０℃とした以外は実施例１と同じ操作でラボプラストミルによる成形性評価を行った結果、樹脂圧上昇は２．１ＭＰａと小さく、成形性は良好であった。
【０１３２】
実施例４：
実施例１のシリカ被覆酸化亜鉛微粒子の合成において、原料酸化亜鉛粒子１．７４Ｋｇの代わりに、酸化チタン粒子（昭和タイタニウム株式会社製高純度酸化チタンＦ−４、一次粒子径３０ｎｍ）を使用した以外は同様の合成法にて、シリカ被覆酸化チタン微粒子を得た。
【０１３３】
そして、得られたシリカ被覆酸化チタン９４質量部にジメチルポリシロキサン（ＫＦ９６−１００ＣＳ 信越化学工業（株）製）６質量部の塩化メチレン溶解液を加え、ヘンシェルミキサー（三井三池鉱山（株）製）にて良く混合し、その後９０℃での真空乾燥により溶媒を除去した後、２００℃、６時間焼成することにより表面疎水化されたシリカ被覆酸化チタンを得た。
【０１３４】
得られたシリカ被覆酸化チタン粉末における、５μｍ以上の粗粒の含有率は１．５質量％であった。
【０１３５】
さらに、表面疎水化された粉末をターボクラシファイア（日清エンジニアリング株式会社製）を用いて乾式精密分級した。得られたシリカ被覆酸化チタン粉末における、５μｍ以上の粗粒の含有量は０．０２質量％であった。
【０１３６】
次に、分級したシリカ被覆酸化チタン粉末３０質量部と、実施例１の分級したシリカ被覆酸化亜鉛粉末７０質量部を混合均一化して、シリカ被覆酸化亜鉛含有粉末とした。このようにして得られたシリカ被覆酸化亜鉛含有粉末における、５μｍ以上の粗粒の含有率は０．０２質量％であった。
【０１３７】
シリカ被覆酸化亜鉛含有粉末２０部とポリプロピレン（サンアロマー（株）製ＰＷ６００Ｎ）８０部とを川田（株）製スーパーミキサーで６００ｒｐｍ、３分間混合した後、中谷（株）製３０ｍｍ異方向２軸押出機にて混練して有機重合体組成物マスターバッチを得た。
【０１３８】
得られた有機重合体組成物マスターバッチについて、実施例１と同様にラボプラストミルによる成形性評価を行った結果、樹脂圧上昇は１．０ＭＰａと低く、成形性は良好であった。
【０１３９】
また、得られた有機重合体組成物マスターバッチについて、実施例１と同様に光触媒作用による耐候劣化試験を行った結果、ヘイズの変化は０．７と小さく、光触媒作用による耐候劣化は非常に小さいことがわかった。
【０１４０】
比較例１：
実施例１において、分級後のシリカ被覆酸化亜鉛含有粉末を、分級前のシリカ被覆酸化亜鉛含有粉末を用いた以外は実施例１と同じ操作を行い、有機重合体組成物マスターバッチを得た。
【０１４１】
得られた有機重合体組成物マスターバッチについて、実施例１と同じ操作でラボプラストミルによる成形性評価を行った結果、樹脂圧上昇は８．６ＭＰａと大きく、成形性はよくなかった。
【０１４２】
ただし、得られた有機重合体組成物マスターバッチを実施例１と同じ操作で光触媒作用による耐候劣化試験を行った結果は、フィルムのヘイズの変化は０．５と小さく、光触媒作用による耐候劣化は非常に少なかった。
このことから、得られたシリカ被膜酸化亜鉛微粒子はポリプロピレンに対する光触媒による耐候劣化は非常に小さいことがわかる。
【０１４３】
比較例２：
比較例１で用いたシリカ被覆酸化亜鉛含有粉末を用いた以外は実施例２と同じ操作を行い、有機重合体組成物マスターバッチを得た。得られた有機重合体組成物マスターバッチについて、実施例２と同じ操作でラボプラストミルによる成形性評価を行った結果、樹脂圧上昇は３．５ＭＰａと大きく、成形性はよくなかった。
【０１４４】
ただし、得られた有機重合体組成物マスターバッチを実施例２と同じ操作で光触媒作用による耐候劣化試験を行った結果は、フィルムのヘイズの変化は０．３と小さく、光触媒作用による耐候劣化は非常に小さかった。
このことから、得られたシリカ被膜酸化亜鉛微粒子はポリエチレンに対する光触媒による耐候劣化は非常に小さいことがわかる。
【０１４５】
比較例３：
比較例１で用いたシリカ被覆酸化亜鉛含有粉末を用いた以外は実施例３と同じ操作を行い、有機重合体組成物マスターバッチを得た。得られた有機重合体組成物マスターバッチについて、実施例３と同じ操作でラボプラストミルによる成形性評価を行った結果、樹脂圧上昇は１５ＭＰａ以上と大きく、成形性はよくなかった。
【０１４６】
比較例４：
実施例１において、疎水化前のシリカ被覆酸化亜鉛含有粉末の代わりに、酸化亜鉛粒子（昭和タイタニウム株式会社製高純度酸化亜鉛ＵＦＺ−４０；一次粒子径２７ｎｍ）を用いた以外は実施例１と同じ操作を行い、有機重合体組成物マスターバッチを得た。得られた有機重合体組成物マスターバッチについて、実施例１と同じ操作でラボプラストミルによる成形性評価を行った結果、樹脂圧上昇は４．２ＭＰａと大きく、成形性はよくなかった。
【０１４７】
また、得られた有機重合体組成物マスターバッチを実施例１と同じ操作で光触媒作用による耐候劣化試験を行った結果は、フィルムのヘイズの変化は８．２と大きく、光触媒作用による耐候劣化が大きかった。このことから、未被膜酸化亜鉛微粒子はポリプロピレンに対する光触媒による耐候劣化が大きいことがわかる。
【０１４８】
比較例５：
実施例２において、疎水化前のシリカ被覆酸化亜鉛含有粉末の代わりに、酸化亜鉛粒子（昭和タイタニウム株式会社製高純度酸化亜鉛ＵＦＺ−４０；一次粒子径２７ｎｍ）を用いた以外は実施例２と同じ操作を行い、有機重合体組成物マスターバッチを得た。得られた有機重合体組成物マスターバッチについて、実施例２と同じ操作でラボプラストミルによる成形性評価を行った結果、樹脂圧上昇は６．５ＭＰａと大きく、成形性はよくなかった。
【０１４９】
また、得られた有機重合体組成物マスターバッチを実施例２と同じ操作で光触媒作用による耐候劣化試験を行った結果は、フィルムのヘイズの変化は６．５と大きく、光触媒作用による耐候劣化が大きかった。このことから、未被膜酸化亜鉛微粒子はポリエチレンに対する光触媒による耐候劣化が大きいことがわかる。
【０１５０】
比較例６：酸化亜鉛粒子（昭和タイタニウム株式会社製高純度酸化亜鉛ＵＦＺ−４０；一次粒子径２７ｎｍ）の水性懸濁液（ＺｎＯ濃度５０ｇ／Ｌ）を８０℃に昇温し、攪拌下、酸化亜鉛に対して、ＳｉＯ _２ として１０重量％のケイ酸ナトリウムの水溶液を加えた。１０分間、熟成した後、６０分かけて撹拌下に硫酸を加え、ｐＨ６．５に中和した。３０分間、熟成した後、得られた懸濁液を濾過、水洗した後、１３０℃で５時間、加熱乾燥した。このようにして得られた乾燥品をジェットミル粉砕して、シリカ被覆酸化亜鉛含有粉末を得た。これを、実施例１における疎水処理前のシリカ被膜酸化亜鉛微粒子に変えて用いた以外は実施例１と同じ操作を行い、有機重合体組成物マスターバッチを得た。
【０１５１】
得られた有機重合体組成物マスターバッチについて、実施例１と同じ操作でラボプラストミルによる成形性評価を行った結果、樹脂圧上昇は２．２ＭＰａと小さく、成形性は良好であった。
【０１５２】
また、得られた有機重合体組成物マスターバッチを実施例１と同じ操作で光触媒作用による耐候劣化試験を行った結果は、フィルムのヘイズの変化は３．５と大きく、光触媒作用による耐候劣化が大きかった。このことから、得られたシリカ被膜酸化亜鉛微粒子はポリプロピレンに対する光触媒による耐候劣化が大きいことがわかる。
【０１５３】
【表３】

【発明の効果】
本発明により、光触媒作用による耐候劣化がなく、有機紫外線吸収剤のようなブリードアウトを引き起こすことが無く、洗濯等に対する耐久性も良好な、かつ、十分な紫外線遮蔽能を有する薄いフィルムや細い繊維等の成形を容易にする、５μｍ以上の粗粒が０．１質量％以下であるシリカ被覆酸化亜鉛含有粉末、それを含有する有機重合体組成物およびその成形品が提供される。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to zinc oxide used in organic polymer compositions, rubber products, paper, cosmetics, paints, printing inks, and the like, and in particular, a powder with a small amount of coarse particles containing silica-coated zinc oxide fine particles. The present invention relates to an organic polymer composition and a molded product thereof.
[0002]
[Prior art]
Zinc oxide has long been known as a white pigment, called zinc white.
When the particle size of such zinc oxide is reduced to about ½ of the visible light wavelength, the scattering effect of the zinc oxide particles becomes extremely small, and visible light is transmitted, but the excellent ultraviolet absorption of zinc oxide. From the effect, it has the optical characteristic of selectively absorbing ultraviolet rays.
[0003]
As an ultraviolet absorber using such zinc oxide particles, Patent Document 1 proposes a resin molded body in which zinc oxide fine powder of 0.1 μm or less is added to a transparent resin. Patent Documents 2 and 3 propose zinc oxide fine particles coated with a silicon compound in order to improve the weather resistance deterioration due to the photocatalytic action of the zinc oxide fine particles and the dispersibility in the resin.
[0004]
Moreover, in patent document 4, the water-soluble alkali metal salt of the saturated or unsaturated monocarboxylic acid which has 7-22 carbon atoms to the slurry containing the zinc oxide composition for pigments, and IB of the periodic table of elements A metal cation selected from the group consisting of II, III, IV, V, VIB, VIIB and VIII and a water-soluble metal salt consisting of an inorganic anion moiety selected from the group consisting of nitrate ion, sulfate ion and halogen ion. And forming and depositing the water-insoluble metal soap of the saturated or unsaturated monocarboxylic acid in situ, and encapsulating the zinc oxide composition for pigment with a coating deposited with the water-insoluble metal soap. A method has been proposed.
[0005]
Moreover, the method of using a solvent (for example, water, organic solvent, etc.) at the time of the surface treatment requires steps such as filtration and drying of the solvent, and the surface treatment agent that precipitates at the time of drying is likely to be unevenly distributed or the powder is aggregated. For this reason, this method has a disadvantage that it is difficult to obtain good dispersibility of the coated zinc oxide particles.
[0006]
On the other hand, in applications related to apparel and packaging materials, there are many applications that require transparency, weather resistance, flexibility, etc. In such cases, thin films and thin fibers that have sufficient UV shielding ability are used. It has been demanded.
[0007]
However, conventional zinc oxide particles are insufficient even if they are surface-treated, so the effect of suppressing photocatalytic activity and zinc ion elution is insufficient, and deterioration of organic materials cannot be avoided. Durability was insufficient.
[0008]
For example, polyester, polyamide, and the like have a problem that it is difficult to use an organic ultraviolet absorber because of high molding processing temperature. Therefore, when zinc oxide particles, which are inorganic UV absorbers, are added to the composition, these resins are easily decomposed and have a property of being easily deteriorated by reacting with zinc ions. Some compositions cannot be obtained.
[0009]
In addition, when dyeing fibers obtained by spinning from a composition containing conventional zinc oxide particles, there is a problem that elution of zinc ions into the dyeing solution is unavoidable.
[0010]
In addition, since the conventional coated zinc oxide particles are mixed with coarse particles, when forming from a resin composition containing the particles, if thin fibers such as multifilaments are formed, thread breakage occurs frequently or is extremely thin. Inflation film molding caused puncture, and tape molding did not increase the draw ratio.
[Patent Document 1]
JP-A-5-171130
[Patent Document 2]
JP-A-5-295141
[Patent Document 3]
Japanese Patent Laid-Open No. 11-302015
[Patent Document 4]
Japanese Patent No. 2501663 (International Publication WO 90/06974)
[0011]
[Problems to be solved by the invention]
The present invention is a thin film or thin fiber that does not cause weathering deterioration due to photocatalysis, does not cause bleed-out like an organic ultraviolet absorber, has good durability against washing, etc., and has sufficient ultraviolet shielding ability It is an object of the present invention to provide a powder with less coarse particles containing specific silica-coated zinc oxide fine particles, an organic polymer composition containing the same, and a molded product thereof.
[0012]
[Means for Solving the Problems]
As a result of intensive studies to achieve the above-mentioned object, the present inventor contains silica-coated zinc oxide containing a small amount of coarse particles containing silica-coated zinc oxide fine particles in which coarse particles of 5 μm or more are 0.1 mass% or less. By using the powder, the combination with the thermoplastic resin does not cause weathering deterioration due to photocatalytic action, does not cause bleed-out like an organic ultraviolet absorber, has good durability against washing, etc. The present inventors have found that a thin film or a thin fiber having ultraviolet shielding ability can be easily formed, and have reached the present invention.
[0013]
That is, this invention consists of the following invention.
(1) Raw material zinc oxide particles in a composition for forming a silica film containing 1) silicic acid containing no organic group and halogen or a precursor capable of producing the silicic acid, 2) water, 3) alkali, and 4) organic solvent A silica-coated zinc oxide-containing powder containing silica-coated zinc oxide fine particles having a surface coated with silica and having a coarse particle size of 5 μm or more of 0.1% by mass or less.
(2) A powder containing silica-coated zinc oxide fine particles whose surface has been hydrophobized by further treating the surface of silica-coated zinc oxide fine particles coated with silica with a hydrophobicity-imparting agent, and having a roughness of 5 μm or more A silica-coated zinc oxide-containing powder having a particle content of 0.1% by mass or less.
(3) The hydrophobicity-imparting agent issiliconeThe silica-coated zinc oxide-containing powder according to (2), which is one or more hydrophobic imparting agents selected from the group consisting of oils, alkoxysilanes, silane coupling agents, and higher fatty acid salts.
(4) The silica-coated zinc oxide-containing powder according to any one of (1) to (3), wherein the silica-coated zinc oxide fine particles have a silica film thickness of 0.5 to 100 nm.
(5) The silica-coated zinc oxide-containing powder according to any one of (1) to (4), wherein the primary particle diameter of the silica-coated zinc oxide fine particles is 1 to 200 nm.
(6) Surface-hydrophobized silica coatingZinc oxideThe silica-coated zinc oxide-containing powder according to (2) or (3), wherein the fine particles have a primary particle diameter of 5 to 120 nm and a silica film thickness of 0.5 to 25 nm.
(7) 1150 to 1250 cm of silica film of silica-coated zinc oxide fine particles^-1And 1000-1100cm^-1Of the absorption peak intensity of the infrared absorption spectrum at I (I = I1 / I2: I1 is 1150 to 1250 cm)^-1Absorption peak intensity, I2 is 1000-1100 cm^-1The silica-coated zinc oxide-containing powder according to any one of (1) to (6), wherein the absorption peak intensity is 0.2 or more and the refractive index of the silica film is 1.435 or more.
(8) The silica-coated zinc oxide-containing powder according to any one of (1) to (7), wherein the photocatalytic activity of the silica-coated zinc oxide-containing powder measured by a tetralin auto-oxidation method is 60 Pa / min or less.
(9) Dye fading rate (ΔABS) measured by sunset yellow method of silica-coated zinc oxide-containing powder₄₉₀The silica-coated zinc oxide-containing powder according to any one of (1) to (8), wherein the / hour) is 0.1 or less.
(10) Organic ultraviolet absorber decomposition rate (ΔABS) measured by the parasol method of silica-coated zinc oxide-containing powder₃₄₀The silica-coated zinc oxide-containing powder according to any one of (1) to (9), wherein the / hour) is 0.01 or less.
(11) The silica-coated zinc oxide according to any one of (1) to (10), wherein the decomposition rate of the organic ultraviolet absorber measured by the ethylhexyl paramethoxycinnamate method is 5% or less. Contains powder.
(12) The silica-coated zinc oxide-containing powder according to any one of (1) to (11), wherein the silica-coated zinc oxide-containing powder contains titanium oxide.
(13) The silica-coated zinc oxide-containing powder according to (12), which contains 2 to 5 parts by mass of titanium oxide with respect to 10 parts by mass of zinc oxide.
(14) The silica-coated zinc oxide-containing powder according to (12) or (13), wherein at least a part of titanium oxide is coated with silica.
(15) The silica-coated zinc oxide according to any one of (12) to (14), wherein the titanium oxide contains a mixed crystal in which a titanium-oxygen-silicon bond is present in the primary particles. Contains powder.
(16) Titanium oxide has a BET specific surface area of Am²/ G, SiO₂The silica-coated zinc oxide-containing powder according to (15), wherein B / A = 0.02 to 0.5 when the content is B mass%.
(17) Titanium oxide has a BET specific surface area of 10 to 200 m²The silica-coated zinc oxide-containing powder according to (15) or (16), wherein the powder is / g.
(18) The silica-coated zinc oxide-containing powder according to any one of (15) to (17), wherein the primary particle diameter of titanium oxide is 0.008 μm to 0.15 μm.
(19) Titanium oxide has a core / shell structure with TiO in the core₂Phase is SiO on the shell₂The silica-coated zinc oxide-containing powder according to any one of (15) to (18), wherein the phase is rich in structure.
(20) An organic polymer composition comprising the silica-coated zinc oxide-containing powder according to any one of (1) to (19) and a thermoplastic resin.
(21) An organic polymer composition comprising the silica-coated zinc oxide-containing powder according to any one of (1) to (19) and a thermoplastic resin.
(22) The organic polymer composition according to (20) or (21), wherein the thermoplastic resin is selected from polyethylene, polypropylene, polystyrene, polyamide, polyester, and polycarbonate.
(23) A molded product obtained by molding the organic polymer composition according to any one of (20) to (22).
(24) The molded body according to (23), wherein the molded body is a molded body selected from fibers, yarns, films, tapes, sheets, hollow bodies, and multilayer structures.
(25) Interior / exterior building materials, machinery, vehicle interior / exterior materials, glass products, home appliances, agricultural materials, electronic equipment, tools, tableware, bath products, toilet articles, furniture, clothing, woven fabrics, non-woven fabrics, fabric products, leather products, At least one selected from the group consisting of paper products, sporting goods, baskets, containers, glasses, signs, piping, wiring, metal fittings, sanitary materials, automotive goods, tents and other outdoor equipment, stockings, socks, gloves, masks, and underwear An article comprising a molded article according to (23) or (24), which is a seed article.
(26) A cosmetic comprising the silica-coated zinc oxide-containing powder according to any one of (1) to (19).
[0014]
DETAILED DESCRIPTION OF THE INVENTION
The zinc oxide-containing powder in the present invention is a powder containing silica-coated zinc oxide fine particles whose surface is coated with silica, and the silica-coated zinc oxide-containing powder in which coarse particles of 5 μm or more are 0.1% by mass or less Is preferred. A powder containing silica-coated zinc oxide fine particles whose surface is hydrophobized by further treating the surface of silica-coated zinc oxide fine particles coated with silica with a hydrophobicity-imparting agent, and having a coarse particle size of 5 μm or more Also preferred is a silica-coated zinc oxide-containing powder in which is 0.1% by mass or less.
[0015]
Hereinafter, the manufacturing method will be specifically described.
[0016]
There is no particular limitation on the method for producing silica-coated zinc oxide fine particles in which the surface that is the raw material of the silica-coated zinc oxide-containing powder of the present invention is coated with silica. For example, as shown in International Publication WO98 / 47476 It can be made by a method (hereinafter referred to as [this method]).
[0017]
The silica-coated zinc oxide fine particles of the present method are at least
1) Silicic acid containing no organic group and halogen or a precursor capable of producing said silicic acid,
2) water,
3) alkali,
4) organic solvent,
A composition for forming a silica film, wherein the water / organic solvent ratio is preferably in the range of 0.1 to 10 by volume, and the silicon concentration is in the range of 0.0001 to 5 mol / liter. Silica-coated zinc oxide obtained by a method in which raw material zinc oxide particles having an average primary particle diameter of 5 nm to 200 nm are brought into contact with a composition for forming a silica coating to selectively coat dense silica on the surface of the zinc oxide particles Can be used. The silica film formed in this way is well suited to the complicated shape of the zinc oxide particles of the base material, and even with a thin film of about 0.5 nm, it has good coverage and the ability to conceal photocatalytic activity. Is expensive. Moreover, since it can be set as a silica film with very little alkali metal content, it has the characteristic that the physical property of a silica coating zinc oxide does not change, even if it is a hot and humid atmosphere, a silica film | membrane does not melt | dissolve.
[0018]
In this method, the silica film forming compositionContainedSilicic acid is, for example, orthosilicic acid and its polymer, metasilicic acid and mesosilicic acid shown in the section of “silicic acid” in the Chemical Dictionary (Kyoritsu Shuppan Co., Ltd., published on March 15, 1944, seventh edition) , Mesotrisilicic acid, mesotetrasilicic acid and the like. Silicic acid does not contain organic groups or halogens.
[0019]
The silicic acid of this method is, for example, tetraalkoxysilane (Si (OR)₄Wherein R is a hydrocarbon group, particularly a C1-C6 aliphatic group), specifically, silicic acid such as tetramethoxysilane, tetraethoxysilane, tetra n-propoxysilane, tetraisopropoxysilane, tetra n-butoxysilane, and the like. Can be obtained by adding water, an alkali, and an organic solvent to the precursor capable of producing the compound, stirring, and advancing the hydrolysis reaction. This method is preferable because it is easy to handle or operate and practical. Of these, tetraethoxysilane is a preferred material.
The following formula X_nSi (OR)_4-n
(Wherein X is a hydrocarbon group, halogen, hydrogen, n is an integer of 1, 2 or 3), a compound having a hydrophobic group such as a hydrocarbon group, halogen or hydrogen represented by the present method It differs from the precursor that can produce silicic acid used in Therefore, trialkoxyalkylsilanes, dialkoxyalkyldialkylsilanes, trialkoxysilanes, dialkoxysilanes, etc. are not suitable as precursors.
[0020]
In addition, water, alkali, and organic solvent are added to tetrahalogenated silane and hydrolyzed, alkali and organic solvent are added to water glass, or water glass is treated with a cation exchange resin to obtain alkali, A composition containing silicic acid can also be obtained by using a method of adding an organic solvent. There are no particular limitations on the tetraalkoxysilane, tetrahalogenated silane and water glass used as the raw material for silicic acid, and those generally used for industrial use or as reagents may be used, but those of higher purity are preferred. Further, the composition for forming a silica film in the present method may contain an unreacted material of the raw material of the above-mentioned silicic acid.
[0021]
Although there is no restriction | limiting in particular in the quantity of the silicic acid in a composition for silica film formation, Preferably it is 0.0001-5 mol / liter as silicon concentration, More preferably, it is the range of 0.001-5 mol / liter. . If the silicon concentration is less than 0.0001 mol / liter, the formation rate of the silica film is extremely slow, which is not practical. On the other hand, when the silicon concentration exceeds 5 mol / liter, silica particles may be formed in the composition without forming a film, which is not preferable.
[0022]
The silicon concentration can be calculated from the amount of silicic acid raw material, for example, tetraethoxysilane, but can also be measured by atomic absorption analysis of the silica film-forming composition. In the measurement, it is preferable to use a spectrum of silicon having a wavelength of 251.6 nm as an analysis line and a frame of acetylene / nitrous oxide.
[0023]
The water used for the composition for forming a silica film is not particularly limited, but if foreign particles are contained in the water, it may be mixed as an impurity in the product. Therefore, water from which particles have been removed by filtration or the like is preferably used.
[0024]
The water used in the composition for forming a silica film is preferably used in a water / organic solvent ratio in the range of 0.1 to 10 by volume ratio. If the water / organic solvent ratio is out of this range in the volume ratio, film formation may not be possible or the film formation rate may be extremely reduced. More preferably, the water / organic solvent ratio is in the range of 0.1 to 0.5 by volume ratio. When the water / organic solvent ratio is in the range of 0.1 to 0.5 by volume ratio, the type of alkali used is not limited, but when the water / organic solvent ratio is 0.5 or more by volume ratio, the alkali is used. It is preferable to form a film using an alkali containing no metal, for example, ammonia, ammonium hydrogen carbonate, ammonium carbonate, or the like.
[0025]
In this method, examples of the alkali used in the composition for forming a silica film include inorganic alkalis such as ammonia, sodium hydroxide, and potassium hydroxide; inorganic alkalis such as ammonium carbonate, ammonium bicarbonate, sodium carbonate, and sodium bicarbonate. Salts; organic alkalis such as monomethylamine, dimethylamine, trimethylamine, monoethylamine, diethylamine, triethylamine, pyridine, aniline, choline, tetramethylammonium hydroxide, guanidine; ammonium formate, ammonium acetate, monomethylamine formate, dimethylamine acetate, Examples include, but are not limited to, organic acid alkali salts such as lactic acid pyridine, guanidinoacetic acid, and aniline acetate.
[0026]
Among these, ammonia, ammonium carbonate, ammonium hydrogen carbonate, ammonium formate, ammonium acetate, sodium carbonate, sodium hydrogen carbonate and the like are particularly preferable from the viewpoint of reaction rate control. In the composition for forming a silica film, the alkali can be used alone or in combination of two or more selected from the above group.
[0027]
There is no restriction | limiting in particular in the purity of the alkali of this method. Any material that is generally used for industrial use or as a reagent may be used, but those having higher purity are suitable.
[0028]
In order to increase the silica film formation rate, it is effective to increase the temperature at which the film is formed.
In this case, it is preferable to select and use an alkali and an organic solvent that hardly volatilize and decompose at the film forming temperature.
[0029]
In this method, the amount of the alkali for film formation can be formed by adding a small amount of about 0.002 mol / liter in the case of sodium carbonate, for example, but a large amount of about 1 mol / liter may be added. Absent. However, it is not preferable to add a solid alkali in an amount exceeding the solubility because it is mixed as an impurity in the metal oxide powder.
[0030]
Further, by using an alkali not containing an alkali metal as a main component, silica-coated metal oxide particles having a low alkali metal content can be produced. Among these, ammonia, ammonium carbonate, and ammonium hydrogen carbonate are particularly preferable from the viewpoints of film formation speed and ease of residue removal.
[0031]
The organic solvent used in the silica film-forming composition in this method is preferably one in which the composition forms a uniform solution, for example, alcohols such as methanol, ethanol, propanol, pentanol, etc .; tetrahydrofuran, 1,4-dioxane, etc. Ethers, acetals, aldehydes such as acetaldehyde, ketones such as acetone, diacetone alcohol, and methyl ethyl ketone; polyhydric alcohol derivatives such as ethylene glycol, propylene glycol, and diethylene glycol can be used. Among these, alcohols are preferably used from the viewpoint of reaction rate control, and ethanol is particularly preferable. As the organic solvent, one or two or more selected from the above group can be mixed and used.
[0032]
There is no particular limitation on the purity of the organic solvent used in the composition for forming a silica film, and it may be industrially used or widely used as a reagent, but preferably has a higher purity.
[0033]
A general solution preparation method can be applied to the preparation of the silica film-forming composition. For example, a method of adding a predetermined amount of alkali and water to an organic solvent and stirring and then adding and stirring tetraethoxysilane can be mentioned. is there. From the viewpoint of reaction controllability, when mixing water and tetraethoxysilane, both are preferably diluted with an organic solvent.
[0034]
The composition for forming a silica film thus prepared is a stable composition, and substantially does not undergo coating or precipitation before being brought into contact with metal oxide particles such as zinc oxide. By bringing the metal oxide particles into contact with the composition, a silica film is selectively formed on the surface of the metal oxide particles. The term “selective” as used herein means that the formation of a film accompanying silica deposition proceeds only on the surface of the metal oxide and does not cause the formation of silica particles due to uniform nucleation in the solution. It means that the silica film thickness and the silica content of the metal oxide can be controlled.
[0035]
There is no particular limitation on the method for producing zinc oxide which is a raw material for the silica-coated zinc oxide fine particles, and any method may be used. Baking of zinc hydroxide, zinc carbonate, zinc sulfide, zinc oxalate, etc. obtained by evaporating and oxidizing electrolytic zinc bullion, or by neutralizing aqueous solutions of water-soluble salts such as zinc sulfate and zinc chloride Or a mixture of these. In addition, zinc oxide doped with a different element such as Fe, Co, Al, Sn, Sb, and further an element selected from Si, Al, Fe, Co, Zr, Ce, Sn, Sb, etc., mainly composed of zinc oxide. It may be a mixed crystal oxide or composite oxide containing a crystalline or non-crystalline oxide. However, those with less aggregation are preferred from the viewpoint of controlling the secondary particle size.
[0036]
The primary particle diameter of the raw material zinc oxide particles used in this method is preferably 1 nm to 200 nm, more preferably 5 nm to 120 nm. The secondary particle diameter is preferably 0.5 μm or less.
[0037]
In this method, the raw material zinc oxide particles are immersed in a composition for forming a silica film and kept at a predetermined temperature to selectively coat the surface of the zinc oxide particles with silica to form a silica film. Can do. As a method for forming a silica film, a method for forming a silica film by adding a raw material zinc oxide particle after preparing a composition for forming a silica film in advance may be used. Alternatively, a raw material zinc oxide particle may be suspended in a solvent in advance. A method of forming a silica film by adding other raw material components to form a composition for forming a silica film may be used. That is, there are no particular restrictions on the order in which the raw material of the film-forming composition and the raw material zinc oxide particles are added, and any of them can form the silica film first.
[0038]
Among these methods, after preparing a suspension containing raw material zinc oxide particles, water, an organic solvent, and an alkali, and dropping tetraalkoxysilane diluted with an organic solvent at a constant rate, the fineness becomes better. It is preferable because a continuous silica film can be formed and an industrially useful continuous process can be constructed.
[0039]
Since the silica film grows by selective coating on the surface of the zinc oxide particles, the film thickness can be increased by increasing the film formation time. Of course, when the raw material of silicic acid in the composition for forming a film is mostly consumed due to the formation of the film, the film forming rate decreases, but by sequentially adding the raw material of silicic acid corresponding to the consumption amount, The silica film can be continuously formed at a practical film formation rate. In particular, the silica coating formed by holding the raw material zinc oxide particles in a film-forming composition to which a raw material of silicic acid corresponding to a desired silica film thickness has been added for a predetermined time to form a silica film and consuming the raw material of silicic acid After the zinc oxide fine particles are taken out of the system, by adding a silicic acid raw material corresponding to the consumption amount, the composition can be subsequently used for forming a film on the next raw material zinc oxide particles. , Can build a continuous process with high productivity.
[0040]
For example, in the case of a method in which a suspension containing raw material zinc oxide particles, water, an organic solvent and an alkali is prepared and then tetraalkoxysilane diluted with an organic solvent is dropped at a constant rate, a desired silica film is used. A dense silica film having a desired film thickness, in which tetraalkoxysilane is completely consumed by dropping a solution obtained by diluting a tetraalkoxysilane corresponding to the thickness into an organic solvent at a constant rate corresponding to the hydrolysis rate. Further, by removing the resulting silica-coated zinc oxide fine particles out of the system, it is possible to obtain a high-purity product having no unreacted tetraalkoxylane remaining. Of course, the solvent after the silica-coated zinc oxide fine particles are taken out can be recycled for the subsequent film formation, and a process with high economic efficiency and productivity can be constructed.
[0041]
Although there is no limitation in particular in the temperature at the time of a silica film formation, Preferably it is the range of 10-100 degreeC, More preferably, it is the range of 20-50 degreeC. The higher the temperature, the higher the film formation rate. However, if the temperature is too high, it will be difficult to keep the solution composition constant due to volatilization of the components in the composition, and if the temperature is too low, the film formation rate will be slow and practical. Not.
[0042]
Moreover, the pH of the composition for forming a silica film at the time of film formation may be alkaline from the viewpoint of the denseness of the film. In addition, since the solubility of zinc oxide may change depending on pH, it is preferable to control the pH of the silica film-forming composition by adjusting the amount of alkali added. However, in that case, the hydrolysis rate of tetraalkoxysilane, for example, changes with the change in the amount of alkali added, so the film formation temperature or the amount of water in the film-forming composition is adjusted to an appropriate hydrolysis rate. There is a need to.
[0043]
After the formation of the silica coating on the zinc oxide particles, the solid-liquid separation can be performed to isolate the silica-coated zinc oxide fine particles. As a method for isolation, general separation methods such as filtration, centrifugal sedimentation, and centrifugal separation can be used.
[0044]
By carrying out drying after the solid / liquid separation, silica-coated zinc oxide fine particles having a low water content can be obtained. As a drying method, a general drying method such as natural drying, warm air drying, vacuum drying, spray drying, or the like can be used. The silica-coated zinc oxide fine particles of the present method do not need to be fired in particular, but can be fired and used as necessary.
[0045]
The silica coating of silica-coated zinc oxide fine particles obtained by this method is a dense and practical silica coating. In this method, “dense” means that the formed silica film is dense, uniform and free of pinholes and cracks, and “practical” means that the silica and the base zinc oxide Bond (—Si—O—Zn— bond) is strong, peeling of the film does not occur, and the physical properties of the silica-coated zinc oxide hardly change.
[0046]
The silica-coated zinc oxide fine particles of the present method are preferably silica-coated zinc oxide having a surface hydrophobized by surface treatment with a hydrophobicity-imparting agent.
[0047]
A known method can be used as a method of surface-treating silica-coated zinc oxide with a hydrophobicity-imparting agent. In this method, for example, silica-coated zinc oxide particles can be directly hydrophobized using a dry method or a spray method. In the dry method, the silica coating is stirred by a mixer such as a V-type mixer or a Henschel mixer.Zinc oxideAdd the hydrophobicity-imparting agent or hydrophobicity-providing organic solvent solution to the fine particles by spraying, etc., continue mixing, uniformly adhere to the powder surface, dry, and if necessary, firm A heating method can be used to adhere to the substrate. Further, in the spray method, a method of spraying a hydrophobicity imparting agent or a solution thereof onto silica-coated zinc oxide particles brought to a high temperature to coat the surface can be used.
[0048]
In the wet method, water or organic solvent or mixed solvent is coated with silica.Zinc oxideA method of performing surface treatment after adding a hydrophobicity imparting agent, a solution thereof, a reaction catalyst, or the like to the liquid in which the fine particles are dispersed and further stirring can be used. In this case, a silica-coated zinc oxide fine particle powder having a hydrophobic surface can be obtained by drying after solid / liquid separation. As a drying method, a general drying method such as natural drying, warm air drying, vacuum drying, spray drying, or the like can be used.
[0049]
Since the silica-coated zinc oxide fine particle powder and the surface-hydrophobized silica-coated zinc oxide fine particle powder are aggregated by drying or firing, a step of reducing coarse particles is required. As a method for reducing coarse particles, dry classification is preferable. For example, precise classification can be performed using a turbo classifier manufactured by Nisshin Engineering Co., Ltd. Strong pulverization such as a jet mill is effective in reducing agglomerated particles, but the silica coating is partially destroyed by pulverization, or a new surface by pulverization of a coarse zinc oxide surface-treated product (zinc oxide surface) Appear, which deteriorates the moldability and weather resistance of the organic polymer composition containing the same. In addition, wet stationary classification using a solvent is not preferable because re-aggregation occurs in the solid-liquid separation / drying step after classification.
[0050]
The hydrophobicity-imparting agent used in the present method is not particularly limited, and examples thereof include higher fatty acids such as wax, higher fatty acid triglycerides, higher fatty acids, higher fatty acid polyvalent metal salts, and higher aliphatic sulfates. Organic compounds such as alcohols or their derivatives, organic fluoro compounds such as perfluoro- or partially fluorinated higher fatty acids and higher alcohols, silicone oils, organic alkoxysilanes, organic chlorosilanes, and silazanesSilicaElementary compounds can be used. Higher fatty acid polyvalent metal salts, silicone oils, silane coupling agents, and alkoxysilanes are preferably used.
[0051]
The silicone oil used in the present method is not particularly limited, and examples thereof include dimethylpolysiloxane, methylhydrogenpolysiloxane, methylphenylpolysiloxane, and cyclic polydimethylsiloxane. Further, modified silicone oils such as alkyl-modified, polyether-modified, amino-modified, mercapto-modified, epoxy-modified and fluorine-modified may be used.
[0052]
There are no particular restrictions on the chlorosilanes used in this method, but trimethylchlorosilane, dimethyldichlorosilane, methyltrichlorosilane, methyldichlorosilane, dimethylvinylchlorosilane, methylvinyldichlorosilane, triphenylchlorosilane, methyldiphenylchlorosilane, diphenyldisilane. Mention may be made of chlorosilane, methylphenyldichlorosilane and phenyltrichlorosilane.
[0053]
Silazanes used in this method are not particularly limited, and examples include hexamethyldisilazane, N, N′-bis (trimethylsilyl) urea, N-trimethylsilylacetamide, dimethyltrimethylsilylamine, diethyltrimethylsilylamine, and trimethylsilylimidazole. .
[0054]
The organoalkoxysilanes used in this method are not particularly limited. For example, vinyltrichlorosilane, vinyltris (β-methoxyethoxy) silane, vinyltrimethoxysilane, vinyltriethoxysilane, γ- (methacryloyloxypropyl) Trimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidyloxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, N-β (aminoethyl) γ-aminopropyl Trimethoxysilane, N-β (aminoethyl) γ-aminopropylmethyldiEthoxySilane coupling agents such as silane, γ-aminopropyltriethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane and γ-chloropropyltrimethoxysilane, and methyltrimethoxysilane, dimethyldimethoxy Silane, trimethylmethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, trimethylethoxysilane, methyldimethoxysilane, methyldiethoxysilane, dimethylethoxysilane, dimethylvinylmethoxysilane, dimethylvinylethoxysilane, phenyltrimethoxysilane, phenyltri Ethoxysilane, diphenyldiMethoxyExamples include silane and diphenyldiethoxysilane. Also, alkoxysilanes having perfluorinated or partially fluorinated alkyl groups can be used.
[0055]
In particular, an alkylalkoxysilane represented by the following formula is preferably used.
[0056]
Formula; R¹(R² _n) SiX_3-n
(Where R¹Is an alkyl group having 1 to 4 carbon atoms or a phenyl group, R²Is a hydrogen group, an alkyl group having 1 to 4 carbon atoms or a phenyl group, X is an alkoxyl group having 1 to 4 carbon atoms, and n is an integer of 0 to 2. )
The coating amount of the hydrophobicity-imparting agent may be not less than the minimum coating amount that allows the hydrophobicity-imparting agent to completely cover the surface of the raw material silica-coated zinc oxide particles. This amount is
Minimum coverage (g) = silica coatingZinc oxideFine particle mass (g) x specific surface area (m²/ G)/Minimum covering area of hydrophobicity imparting agent (m²)
Can be calculated. Silica coating when excessive amount of hydrophobicity-imparting agent is addedZinc oxideSince the amount of precipitation on the surface other than the surface of the fine particles increases, it is not economical. Hydrophobic agent molecular weight, silica coatingZinc oxideSince it depends on the specific surface area of the fine particles, it cannot be decided unconditionally.Zinc oxide0.1-30 mass% or less is preferable with respect to microparticles | fine-particles, More preferably, it is 1-20 mass% or less. If it is 0.1% by mass or less, it is not preferable because sufficient hydrophobicity cannot be obtained. On the other hand, if it is 30% by mass or more, sufficient hydrophobicity can be obtained, but this is not preferable because the reduction in the content of zinc oxide per unit weight results in a decrease in ultraviolet shielding ability.
[0057]
The silica-coated zinc oxide fine particles used in the present method have a silica film thickness of 0.5 to 100 nm, preferably 1.0 to 50 nm, and more preferably 1.5 to 25 nm.
A silica film thickness of 0.5 nm or less is not preferable because a sufficient photocatalytic activity hiding effect cannot be obtained, and a stable organic polymer composition, molded product, or structure may not be obtained. On the other hand, if it exceeds 100 nm, an organic polymer composition, a molded product or a structure having a sufficient ultraviolet shielding ability may not be obtained. The silica film thickness is determined from a transmission electron microscope image.
[0058]
The silica-coated zinc oxide fine particles of this method have a primary particle size of 1 to 200 nm, preferably 5 to 120 nm. If the primary particle diameter is out of the above range, an organic polymer composition, a molded product or a structure having a high ultraviolet shielding ability may not be obtained.
[0059]
The “primary particles” as used in this method are those defined by Kuichiro Keiichiro et al., “Powder”, p. 56-66, published in 1979.
[0060]
Silica-coated zinc oxide fine particles obtained by the above method have 1150 to 1250 cm.^-1And 1000-1100cm^-1Absorbance peak absorbance ratio I (I = I 1 / I 2: I 1 is 1150 to 1250 cm^-1Absorption peak intensity (absorbance), I2 is 1000-1100 cm^-1Is a value obtained by subtracting the baseline), and is 0.2 or more, preferably 0.3 or more, and more preferably 0.4 or more. The transmission infrared absorption spectrum of the silica film of silica-coated zinc oxide can be measured using the KBr powder method.
[0061]
Usually, a silica film obtained by baking by a sol-gel method or the like or obtained by a CVD method has a thickness of 1150 to 1250 cm.^-1And 1000-1100cm^-1The ratio I of the absorption peak intensity of the infrared absorption spectrum at is generally less than 0.2. It is known that the value of I generally changes the chemical bond or functional group by firing, and changes the hydrophilic and oil-absorbing properties of the silica film.
[0062]
The refractive index of the silica layer of the silica-coated zinc oxide fine particles in this method is preferably 1.435 or more, and more preferably 1.440 or more. If the refractive index is less than 1.435, the denseness is lowered, which is not preferable. Moreover, the silica film obtained without baking by a normal sol-gel method has a refractive index of less than 1.435, and is not practical because of low density. Here, it is generally assumed that there is a positive correlation between the denseness of the silica film and the refractive index. (For example, C. JEFFERY BRINKER, SOL-GEL SCIENCE, 581-583, ACADEMI PRESS (1990)) In this method, “dense” means that the formed silica film has a high density, uniform pinholes and cracks In addition, “practical” means that the bond between the silica and the zinc oxide as the base material (—Si—O—Zn—bond) is strong, and the coating is not peeled off. This means that the physical properties of zinc oxide are difficult to change.
[0063]
The refractive index is measured using a silica film formed on a silicon wafer that is simultaneously immersed in the composition for forming a silica film when synthesizing the silica-coated zinc oxide. That is, it is considered that the same silica film as that on the zinc oxide particles is formed on this silicon wafer. The refractive index of the silica film on the silicon wafer can be measured with an ellipsometer (ULVAC; LASSER ELLIPOSOMETER ESM-1A).
[0064]
The photocatalytic activity (namely, initial oxygen consumption amount) of the silica-coated zinc oxide fine particles by the tetralin auto-oxidation method of this method is 60 pa / min or less, preferably 50 Pa / min or less. When the photocatalytic activity by the tetralin auto-oxidation method exceeds 60 pa / min, a sufficient effect of suppressing the photocatalytic activity cannot be obtained and sufficient durability may not be obtained.
[0065]
The tetralin auto-oxidation method is described in "Satoru Kiyono, Titanium oxide-physical properties and applied technology, Gihodo Shuppan, p.196-197, 1991". The measurement conditions are a temperature of 40 ° C., tetralin 20 ml, and zinc oxide 0.02 g.
[0066]
The photocatalytic activity of the silica-coated zinc oxide fine particles in this method is measured by the dye fading rate by the sunset yellow method described in the examples, the parasol 1789 method, and the ethylhexyl paramethoxycinnamate method.
[0067]
The dye fading rate (ΔABS490 / hour) measured by the sunset yellow method of the silica-coated zinc oxide fine particles of this method is preferably 0.1 or less, more preferably 0.05 or less. When the dye fading speed exceeds 0.1, the effect of suppressing the photocatalytic activity is not sufficient, and sufficient durability may not be obtained.
[0068]
The decomposition rate of the organic ultraviolet absorbent (= parasol 1789) measured by the parasol 1789 method of silica-coated zinc oxide fine particles in this method is preferably 0.02 or less, more preferably 0.01 or less. If the decomposition rate of the organic ultraviolet absorber measured by the Parasol 1789 method exceeds 0.02, the effect of suppressing the photocatalytic activity is not sufficient, and sufficient durability may not be obtained.
[0069]
The decomposition rate of the organic ultraviolet absorber (= ethylhexyl paramethoxycinnamate) of the silica-coated zinc oxide in this method measured by the ethylhexyl paramethoxycinnamate is preferably 5% or less, more preferably 3% or less. When the organic ultraviolet absorber decomposition rate measured by the ethyl hexyl paramethoxycinnamate exceeds 5%, the effect of suppressing the photocatalytic activity is not sufficient, and sufficient durability may not be obtained.
[0070]
The content of coarse particles of 5 μm or more in the silica-coated zinc oxide-containing powder can be measured as follows.
[0071]
When the sample is a powder containing silica-coated zinc oxide fine particles whose surface is coated with silica, 20 g of the sample is accurately weighed, placed in 1800 ml of pure water at room temperature, and stirred well. An appropriate amount (10 ml) of a dispersant, for example, 10% aqueous solution of sodium hexametaphosphate is added and stirred, followed by ultrasonic dispersion for 10 minutes. For ultrasonic dispersion, for example, an ultrasonic homogenizer manufactured by Nippon Seiki Seisakusho Co., Ltd. (model US-300T output 300 W transmission frequency 20 kHz) can be used. Thereafter, the suspension was opened on a high-precision micromesh sieve having a mesh size of 5 μm set in an ultrafine powder classifier (model PS-80) manufactured by Yokohama Rika Co., Ltd., and an ultrasonic vibrator incorporated in the apparatus. Wet precision classification is performed by electromagnetic vibrator and suction pump. After classification, the powder on the sheave is collected by spraying water from a washing bottle and put into a glass container together with pure water. This is put into a 110 ° C. drier, and after moisture is evaporated, the remaining residue is collected and weighed. The proportion of the residue in 20 g of the original sample becomes coarse particles having a size of 5 μm or more.
[0072]
When the sample is a powder containing silica-coated zinc oxide fine particles whose surface is hydrophobized by further treating the surface of silica-coated zinc oxide fine particles coated with silica with a hydrophobicity-imparting agent, wet precision Classification can be performed in the above classification operation by changing the solvent other than the dispersant from water to an equal volume mixed solvent of water and methanol. After classification, the powder on the sieve is air-dried and then placed in a 110 ° C. dryer, and the remaining residue is collected and weighed. The proportion of the residue in 20 g of the original sample becomes coarse particles having a size of 5 μm or more.
[0073]
The content of coarse particles of 5 μm or more in the powder containing the silica-coated zinc oxide fine particles thus obtained is preferably 0.1% by mass or less. More preferably, it is 0.05 mass% or less.
[0074]
If the content of coarse particles of 5 μm or more exceeds 0.1% by mass, for example, the amount of yarn breakage frequently occurs when forming thin fibers such as multifilaments with a blending amount that substantially demonstrates the ultraviolet shielding effect. Or, the ultrathin inflation film molding may cause puncture, or the tape molding may not increase the draw ratio.
[0075]
By using the above silica-coated zinc oxide-containing powder, by combining with a thermoplastic resin, it is easy to form a thin film, a thin thread or the like that has no weathering deterioration due to photocatalytic action and has sufficient ultraviolet shielding ability. be able to.
[0076]
The silica-coated zinc oxide-containing powder may contain titanium oxide. By containing titanium oxide, it is possible to further enhance the UV protection ability. Here, it is preferable that 2 parts by mass to 5 parts by mass of titanium oxide is included with respect to 10 parts by mass of zinc oxide, more preferably 2.5 parts by mass to 5 parts by mass, and further preferably 3 parts. Parts by mass to 5 parts by mass. In order to enhance the ultraviolet ray protection ability by mixing titanium oxide, it is preferable that 2 parts by mass or more of titanium oxide is contained. However, when the amount exceeds 5 parts by mass, whitening due to titanium oxide increases. It may not be preferable.
[0077]
The titanium oxide to be contained is preferably silica-coated titanium oxide obtained by coating titanium oxide with silica in the same manner as the silica-coated zinc oxide described above. There is no particular limitation on the method for producing titanium oxide which is a raw material for silica-coated titanium oxide, and any method may be used. TiCl_FourHigh temperature vapor phase oxidation of TiCl_FourThose produced by any of the production methods such as vapor phase hydrolysis, sulfuric acid method, and chlorine method can be used. The crystal form of titanium oxide may be any of amorphous, rutile, anatase, buccite, etc., or a mixture thereof. However, those with as few impurities as possible are preferred, and those with little aggregation are preferred from the viewpoint of controlling the secondary particle size.
[0078]
Further, as the titanium oxide to be contained, an ultrafine mixed crystal oxide containing a mixed crystal in which a titanium-oxygen-silicon bond is present in the primary particles may be used. There is no particular limitation on the method for producing an ultrafine mixed crystal oxide containing a mixed crystal in which a titanium-oxygen-silicon bond is present in the primary particles, but for example, a method as shown in International Publication WO01 / 56930 Can be made.
[0079]
The ultrafine particle mixed crystal oxide containing a mixed crystal in which a titanium-oxygen-silicon bond is present in the primary particle has a BET specific surface area of Am.²/ G, SiO ₂ When the content is B mass%, B / A is generally 0.02 to 0.5, preferably 0.05 to 0.3. If B / A is smaller than 0.02, the dispersibility of the ultrafine mixed crystal oxide in the organic polymer composition is poor, and the weather resistance of the molded product is deteriorated. If it is larger than 0.5, SiO on the particle surface₂This is not preferable because the coating with the phase increases and the effect of improving the ultraviolet shielding ability is reduced.
[0080]
The ultrafine particle mixed crystal oxide containing a mixed crystal in which a titanium-oxygen-silicon bond is present in the primary particle has a BET specific surface area of 10 to 200 m.²/ G, preferably 15-100 m²/ G. 200m²If it is larger than / g, it is difficult to produce efficiently and 10 m²If it is smaller than / g, the effect of improving the ultraviolet shielding ability is lowered, which is not preferable. The average primary particle diameter is generally 0.008 μm to 0.15 μm, preferably 0.015 μm to 0.1 μm. If it is less than 0.008 μm, it is difficult to produce efficiently, and if it exceeds 0.15 μm, the effect of improving the ultraviolet shielding ability is lowered, which is not preferable.
[0081]
The ultrafine mixed crystal oxide may have a core / shell structure, but in this case, the core has TiO.₂Phase is SiO on the shell₂A phase rich structure is preferred. At this time, SiO₂The phase is in a state of being supported on a part of the particle surface, and even if it is supported discontinuously like dot-like or island-like, it is supported continuously like string-like, net-like or porous. Alternatively, a continuous portion and a discontinuous portion may be mixed.
[0082]
The silica-coated zinc oxide-containing powder of the present invention can also be used as a cosmetic.
In this case, using normal raw materials that can be normally blended and using a normal production method, any dosage form such as W / O type or O / W type emulsifying type, liquid, solid or gel type can be obtained. Can do. For example, extender pigments (mica, talc, kaolin, calcium carbonate, magnesium carbonate, silicic anhydride, aluminum oxide, barium sulfate, etc.), white pigments (titanium dioxide, zinc oxide, etc.), and colored pigments (eg, bengara, yellow iron oxide) , Black iron oxide, chromium oxide, ultramarine, bitumen, carbon black, etc.), spherical powder (nylon powder, polymethyl methacrylate powder, etc.), oil (liquid paraffin, squalane, castor oil, glyceryl diisostearate, glyceryl triisostearate Rate, glyceryl tri-2-ethylhexanoate, isopropyl myristate, glyceryl triisostearate, dimethylpolysiloxane, methylphenylpolysiloxane, petrolatum, diisostearyl malate, purified lanolin, etc.), UV absorber (benzophenone series) , Salicylic acid-based, PABA-based, cinnamic acid-based, dibenzoylmethane-based, Urikanin acid, etc.), the existing emulsifier, can be blended and existing anti-inflammatory component is not particularly limited thereto.
Since the silica-coated zinc oxide-containing powder used in the present invention has a high effect of suppressing photocatalytic activity, even when used in combination with an organic ultraviolet absorber, the decomposition of the absorber is suppressed and the cosmetic has a high ultraviolet shielding ability. And the effect can be maintained for a long time.
[0083]
Furthermore, when used together with an antioxidant which is a substance having an antioxidant action, the photocatalytic activity of silica-coated titanium oxide and silica-coated zinc oxide can be further suppressed by suppressing the amount of free radicals generated by ultraviolet rays, A safe cosmetic with excellent dosage form stability and low phototoxicity can be obtained.
[0084]
The amount of the silica-coated zinc oxide-containing powder of the present invention is preferably 5 to 25% by mass, more preferably 5 to 20% by mass, based on the total amount of the cosmetic. When the blending amount is 5% by mass or less, the ultraviolet ray protection effect is insufficient, and when the blending amount of the silica-coated zinc oxide-containing powder is 25% by mass or more, whitening occurs at the time of skin application or roughening occurs, which is not preferable. .
[0085]
The silica-coated zinc oxide-containing powder of the present invention can be mixed with a thermoplastic resin to obtain an organic polymer composition. The thermoplastic resin is not particularly limited. For example, polyethylene, polypropylene, polystyrene, polyethylene terephthalate, AS resin, ABS resin, AES resin, polyvinylidene chloride, methacrylic resin, polyvinyl chloride, polyamide, polycarbonate, polyallyl. Examples thereof include esters, polyimides, polyacetals, polyether ketones, polyether sulfones, polyphenyl oxides, and polyphenylene sulfides. The content of the silica-coated zinc oxide-containing powder in the organic polymer composition is generally 0.01 to 80% by mass, preferably 0.1 to 50% by mass, and particularly preferably 1 to 20% by mass. Moreover, as a masterbatch, it is 1-80 mass% generally, and 10-40 mass% is preferable.
[0086]
For thermoplastic resins, antioxidants, anti-aging agents, UV absorbers, lubricants, antistatic agents, surfactants, fillers such as calcium carbonate, talc, plasticizers, stabilizers, foaming agents Commonly used additives such as swelling agents, conductive powders, conductive short fibers, deodorants, softeners, thickeners, viscosity reducing agents, diluents, water repellents, oil repellents, crosslinkers, curing agents, etc. Agents, colorants and fluorescent agents can be added.
[0087]
However, for applications such as thin films and fine fibers, it is preferable that these additives, colorants, and fluorescent agents do not contain coarse particles or coarse fibers. These additives, colorants, fluorescent agents, and the like may be kneaded into the thermoplastic resin, or may be added and molded during molding.
[0088]
An organic polymer composition composed of silica-coated zinc oxide-containing powder and a thermoplastic resin is obtained by mixing silica-coated zinc oxide-containing powder and a thermoplastic resin. However, since the silica-coated zinc oxide-containing powder is a fine powder, it is preferable not only to simply mix the silica-coated zinc oxide-containing powder and the thermoplastic resin but also to knead to improve the uniformity. Additives, colorants, fluorescent agents, and the like can be added and kneaded during mixing or kneading.
[0089]
For mixing the silica-coated zinc oxide-containing powder and the thermoplastic resin, for example, a mixer such as a V-type mixer or a Henschel mixer can be used. For kneading, a batch kneader such as a Banbury mixer, a single screw extruder, a twin screw extruder, or a continuous kneader such as a continuous mixer can be used.
[0090]
The organic polymer composition composed of the silica-coated zinc oxide-containing powder and the thermoplastic resin can be used alone, but can also be used as a master batch added to the dilution thermoplastic resin.
[0091]
The thermoplastic resin for dilution is not particularly limited. For example, polyethylene, polypropylene, polystyrene, polyethylene terephthalate, AS resin, ABS resin, AES resin, polyvinylidene chloride, methacrylic resin, polyvinyl chloride, polyamide , Polycarbonate, polyallyl ester, polyimide, polyacetal, polyether ketone, polyether sulfone, polyphenyl oxide, polyphenylene sulfide and the like.
[0092]
The organic polymer composition of the present invention is usually used alone or as a master batch for thermoplastic resins such as injection molding, hollow molding, extrusion molding, calendar molding, fluid molding, compression molding, melt blown method, and spunbond method. It can be used for a molding method, and a molded product such as a fiber, a thread, a film, a sheet, a tape, a molded product such as an injection molded product, or a hollow body such as a hollow fiber, a pipe, or a bottle can be produced. Moreover, a molded object can also be manufactured by the secondary molding method normally used for thermoplastic resins, such as vacuum forming, pressure forming, and lamination molding.
[0093]
Molded products such as fibers, yarns, films, sheets, tapes, injection molded articles and the like, and hollow articles such as hollow fibers, pipes, and bottles made of the organic polymer composition of the present invention are thin molded articles. There are no particular restrictions on the compact, from the thick compact to the thin compact. However, the organic polymer composition of the present invention is particularly characterized in that it can produce thin molded bodies and thin molded bodies that are usually difficult to obtain, and is optimal for the production of thin fibers and threads, thin films, tapes and the like. .
[0094]
These molded bodies may have a single-layer structure or a multilayer structure. In the case of a multilayer structure, a molded body provided with a layer made of the organic polymer composition of the present invention on the surface has high efficiency of ultraviolet shielding.
[0095]
The moldability in a small extruder can be used as an index for the moldability when the organic polymer composition of the present invention is used alone or as a master batch for various moldings. For example, for an organic polymer composition masterbatch, the resin pressure rise when a certain amount is extruded with respect to the resin pressure immediately after the start of kneading using a lab plast mill manufactured by Toyo Seiki Co., Ltd. Not only expresses the properties, but the organic polymer composition masterbatch is diluted as it is or diluted with a diluting thermoplastic resin to form thin films such as blown film molding, and fine fibers such as multifilament molding. It also serves as an index of moldability when molding. When the increase in the kneading resin pressure of the organic polymer composition master batch is low, not only the moldability of the organic polymer composition master batch in the lab plast mill is good, but also the occurrence of puncture is suppressed in thin film molding. In forming thin fibers and the like, thread breakage and the like are suppressed, and good moldability can be obtained.
[0096]
For example, in the case of an organic polymer composition masterbatch in which the thermoplastic resin is polypropylene, a full flight type 20 mmφ extruder equipped with a screen of 100/630/100/80/60 mesh is placed at 230 (inlet) at 45 rpm. ) When extruding at a temperature of −230-230-230 ° C., the resin pressure rise when 3 kg of the organic polymer composition master batch is extruded with respect to the resin pressure immediately after the start of kneading is preferably 5 MPa or less. The following is more preferable.
[0097]
In the case of an organic polymer composition masterbatch in which the thermoplastic resin is polyamide, a full flight type 20 mmφ extruder equipped with a 100/630/100/80/60 mesh screen is placed at 270 (inlet) at a rotation speed of 45 rpm. ) When extruding at a temperature of −270-270-270 ° C., the resin pressure rise when 3 kg of the organic polymer composition master batch is extruded with respect to the resin pressure immediately after the start of kneading is preferably 10 MPa or less, preferably 5 MPa. The following is more preferable.
[0098]
Fiber products, yarns, films, sheets, tapes, mold products such as injection molded articles, hollow fibers such as hollow fibers, pipes, bottles, etc., fibers, films, sheets or tapes, etc., comprising the organic polymer composition of the present invention In addition to being used alone, it is co-extrusion molded with other thermoplastic resins, molded integrally with the substrate, or affixed to the surface of the substrate to form a surface layer and substrate composed of an organic polymer composition. A multilayer structure made of the material can be formed. The thickness of the film, sheet or tape is not particularly limited and is appropriately selected depending on the application, but is generally 0.0005 to 5.0 mm, preferably 0.001 to 1.0 mm, particularly preferably 0. 0.001 to 0.1 mm. Further, the thickness of the fiber is not particularly limited and is appropriately selected depending on the application, but is generally 1 to 500 denier, preferably 1 to 100, and particularly preferably 1 to 50 denier.
[0099]
Fiber products, films, yarns, sheets, tapes, mold products such as injection molded articles, hollow bodies such as hollow fibers, pipes, bottles, etc., fibers, films, sheets or tapes comprising the organic polymer composition of the present invention Can be affixed to the substrate surface via an adhesive.
As the adhesive, urethane, acrylic, polyvinyl alcohol, vinyl acetate, and the like can be used. In addition, fibers, yarns, films, sheets, tapes, molded products such as injection molded articles, hollow fibers such as hollow fibers, pipes, bottles, etc., fibers, films, sheets, etc., comprising the organic polymer composition of the present invention Alternatively, the tape can be provided with a peelable protective film through an adhesive layer. As the protective film, a coated paper in which a silicone resin is laminated as a release layer, a biaxially stretched polyethylene terephthalate film, or the like can be used. Thus, by setting it as the structure which provided the contact bonding layer and the protective film, a protective film can be peeled and it can stick on arbitrary base-material surfaces.
[0100]
Fibers, yarns, films, sheets, tapes, mold products such as injection molded articles, hollow bodies such as hollow fibers, pipes, bottles, etc., fibers, films, sheets, or the like comprising the organic polymer composition of the present invention. The tape can be subjected to pattern printing, embossing of a concavo-convex pattern, or a three-dimensional shape.
[0101]
The material and shape of the substrate are not particularly limited as long as the ultraviolet shielding ability can be formed on the surface. Examples of the material of the base material include, for example, metals such as iron, aluminum and copper, ceramics such as glass and ceramics, inorganic materials such as gypsum, calcium silicate, and cement, polyvinyl chloride, polyester, polyolefin, polycarbonate, polyamide, and acrylic resin. Plastics such as ABS resin, polystyrene, phenol resin, and FRP, organic materials such as wood, plywood, and paper, fibers such as glass fiber, carbon fiber, and polyester fiber are used. Multi-layer structures such as fibers, yarns, films, sheets, tapes, injection-molded articles such as injection molded articles, and hollow bodies such as hollow fibers, pipes, and bottles made of the organic polymer composition of the present invention can be formed. . The shape of the substrate is arbitrary, such as a film, a sheet, a plate, a fiber, a woven fabric, a nonwoven fabric, and a three-dimensional shape, and the size is not particularly limited.
[0102]
The molded body and multilayer structure described above may be used alone or may be included in a part of another structure. Such a structure is not particularly limited, and may be composed of inorganic materials such as metal, concrete, glass, and ceramics, and composed of organic materials such as paper, plastic, wood, and leather. It may be a thing, or a combination thereof. Examples of these articles include, for example, packaging materials, building materials, machines, vehicles, glass products, home appliances, agricultural materials, electronic equipment, tools, tableware, bath products, toilet products, furniture, clothing, fabric products, textiles, leather products. Paper products, sporting goods, baskets, containers, glasses, signs, piping, wiring, metal fittings, sanitary materials, automotive goods, tents, stockings, socks, gloves, masks, underwear, etc.
[0103]
The organic polymer composition containing the silica-coated zinc oxide-containing powder of the present invention is very excellent in moldability and processability, and the molded product made of this organic polymer composition is extremely excellent in weather resistance. Become.
Excellent formability and processing especially in stockings, socks, underwear, etc. obtained by molding and processing ultrafine fibers such as multifilaments, packaging materials obtained by molding and processing ultrathin films, agricultural materials, etc. And weather resistance.
Furthermore, the molded / processed product according to the present invention has a feature that there is no bleed-out like an organic ultraviolet absorber. Therefore, in stockings, socks, underwear, etc., the durability against washing is very excellent even after molding.
[0104]
【Example】
Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples.
[0105]
The following evaluation was performed in the following examples and comparative examples.
(Silica film thickness measurement) Silica-coated zinc oxide fine particles were observed with a transmission electron microscope (JEM2010, acceleration voltage 200 V manufactured by JEOL Ltd.), and the silica film on the particle surface (to cover the substrate with respect to the substrate) The thickness of the film portion having a thin contrast, which is observed in FIG.
(Average primary particle diameter) Silica-coated zinc oxide fine particles are observed with a transmission electron microscope (JEM 2010, acceleration voltage 200V, manufactured by JEOL Ltd.), 100 particles are arbitrarily extracted, and the particle diameter of each particle is measured. The average particle size was calculated.
(IR spectrum measurement) Infrared absorption spectrum (FT-IR-8000 manufactured by JASCO Corporation) of silica film of silica-coated zinc oxide fine particles was measured by KBr method (Silica-coated zinc oxide fineThe mixing ratio of each particle and KBr powder is:Silica-coated zinc oxide fineParticle / KBr mass ratio was 1/32). 1150-1250cm^-1And 1000-1100cm^-1The absorbance of the absorption peak is calculated from the transmittance of the infrared absorption spectrum of the sample, and the absorption peak intensity ratio I (I = I1 / I2: I1 is 1150 to 1250 cm).^-1Absorption peak absorbance, I2 is 1000-1100 cm^-1(Absorbance of absorption peak).
(Refractive Index Measurement) Using a silica film formed on a silicon wafer immersed in the system when synthesizing silica-coated zinc oxide fine particles, an ellipsometer (manufactured by ULVAC; LASSER ELLIPOSOMETER ESM-1A) was used for measurement.
(Tetralin Auto-Oxidation Method) “Sugano Kiyoshi, Titanium oxide—Physical properties and applied technology, Gihodo Shuppan, p. 196-197, 1991”. The measurement conditions are a temperature of 40 ° C., tetralin 20 ml, and zinc oxide 0.02 g.
(Measurement of dye fading rate / Sunset Yellow method) The obtained silica-coated zinc oxide fine particles, uncoated zinc oxide particles (raw material zinc oxide particles) and commercially available zinc oxide (ZnO350, manufactured by Sumitomo Osaka Cement Co., Ltd.) were tested. The dye fading speed was measured by the sunset yellow method.
[0106]
First, Sunset Yellow FCF (manufactured by Wako Pure Chemical Industries, Ltd.) as a pigment was dissolved in 98% by mass glycerin so that the pigment concentration was 0.02% by mass. The test substance is dispersed so as to be 0.067% by mass, and the dispersion is irradiated with ultraviolet rays (ultraviolet intensity: 1.65 mW / cm²)did. Absorbance at 490 nm, which is the maximum absorption wavelength of Sunset Yellow FCF, is measured over time with a spectrophotometer (UV-160 manufactured by SHIMADZU) at an optical path length of 1 mm. Difference in absorbance decrease rate (ΔABS₄₉₀/ Hour) was calculated.
(Measurement of decomposition rate of organic UV absorbers, Parasol 1789 method)
Using the obtained silica-coated zinc oxide, uncoated zinc oxide (raw material zinc oxide particles) and commercially available zinc oxide (ZnO350, manufactured by Sumitomo Osaka Cement Co., Ltd.) as the test substances, the decomposition rate of parasol 1789, which is an organic ultraviolet absorber, was determined. It was measured.
[0107]
That is, a test substance was dispersed in a polyethylene glycol 300 solution of 4-tert-butyl-4′-methoxydibenzoylmethane (parasol 1789) (parasol 1789 concentration 0.045% by mass) to form a slurry of 1% by mass. . Put 1.2 g of slurry in a glass container and irradiate with ultraviolet rays for 10 hours (1.65 mW / cm²), 1 g was collected, and 2 mL of isopropyl alcohol, 2 mL of hexane, and 3 mL of distilled water were sequentially added. The mixture was stirred to extract parasol 1789 in the hexane phase, and the absorbance (340 nm) at an optical path length of 1 mm of the hexane phase was measured with a spectrophotometer (UV-160 manufactured by SHIMADZU). Difference between absorbance decrease rate at 340 nm and absorbance decrease rate in blank test (no addition of zinc oxide) (ΔABS₃₄₀/ Hour).
(Measurement of decomposition rate of organic UV absorber, ethylhexyl paramethoxycinnamate) The obtained silica-coated zinc oxide fine particles and uncoated zinc oxide (raw zinc oxide particles) and commercially available zinc oxide (ZnO350, Sumitomo Osaka Cement Co., Ltd.) The decomposition rate of ethylhexyl paramethoxycinnamate, which is an organic ultraviolet absorber, was measured.
[0108]
That is, the test substance was dispersed in a polyethylene glycol 300 solution of 2-ethylhexyl paramethoxycinnamate (0.05% by mass as 2-ethylhexyl paramethoxycinnamate) to form a slurry of 0.33% by mass. Put 1.2 g of slurry in a glass container and irradiate with UV for 90 minutes (1.65 mW / cm²), 1 g was collected, and 2 mL of isopropyl alcohol, 2 mL of hexane, and 3 mL of distilled water were sequentially added. The mixture was stirred and 2-ethylhexyl paramethoxycinnamate was extracted from the hexane phase, and the absorbance (300 nm) at an optical path length of 1 mm of the hexane phase was measured with a spectrophotometer (UV-160 manufactured by SHIMADZU). The decomposition rate of 2-ethylhexyl paramethoxycinnamate was determined from the difference between the absorbance decrease at 300 nm and the absorbance decrease in the blank test (no addition of zinc oxide).
(Zinc dissolution test)
The elution property of zinc ions into water of the silica-coated zinc oxide-containing powder was evaluated as follows.
[0109]
The amount of zinc ions eluted is that silica-coated zinc oxide (including surface hydrophobized products) and uncoated zinc oxide are dispersed in various pH solutions at 5% by mass, stirred at 25 ° C for 3 hours, and then the dispersion is centrifuged. The amount of zinc ions in the supernatant was measured with an atomic absorption spectrophotometer (Z-8200, manufactured by Hitachi, Ltd.).
(Content of coarse particles of 5 μm or more)
When the sample is a powder containing silica-coated zinc oxide fine particles whose surface is coated with silica, 20 g of the sample is accurately weighed, placed in 1800 ml of pure water at room temperature, and stirred well. An appropriate amount (10 ml) of a dispersant, for example, 10% aqueous solution of sodium hexametaphosphate is added and stirred, followed by ultrasonic dispersion for 10 minutes. For ultrasonic dispersion, for example, an ultrasonic homogenizer manufactured by Nippon Seiki Seisakusho Co., Ltd. (model US-300T output 300 W transmission frequency 20 kHz) can be used. Thereafter, the suspension was opened on a high-precision micromesh sieve having a mesh size of 5 μm set in an ultrafine powder classifier (model PS-80) manufactured by Yokohama Rika Co., Ltd., and an ultrasonic vibrator incorporated in the apparatus. Wet precision classification is performed by electromagnetic vibrator and suction pump. After classification, the powder on the sheave is collected by spraying water from a washing bottle and put into a glass container together with pure water. This is put into a 110 ° C. drier, and after moisture is evaporated, the remaining residue is collected and weighed. The proportion of the residue in 20 g of the original sample becomes coarse particles having a size of 5 μm or more.
[0110]
When the sample is a powder containing silica-coated zinc oxide fine particles whose surface is hydrophobized by further treating the surface of silica-coated zinc oxide fine particles coated with silica with a hydrophobicity-imparting agent, wet precision Classification can be performed in the above classification operation by changing the solvent other than the dispersant from water to an equal volume mixed solvent of water and methanol. After classification, the powder on the sieve is air-dried and then placed in a 110 ° C. dryer, and the remaining residue is collected and weighed. The proportion of the residue in 20 g of the original sample becomes coarse particles having a size of 5 μm or more.
(Kneading resin pressure)
For various organic polymer composition master batches composed of silica-coated zinc oxide-containing powder and a thermoplastic resin, the kneading resin pressure was measured using a lab plast mill manufactured by Toyo Seiki Co., Ltd., and the moldability was evaluated. The labo plast mill kneading conditions were a full flight type 20 mmφ extruder equipped with a 100/630/100/80/60 mesh screen at 45 rpm and the temperature conditions were adjusted according to the type of resin. The moldability was evaluated by increasing the resin pressure when 3 kg of the organic polymer composition master batch was extruded against the resin pressure immediately after the start of kneading.
(Inhibition of weather resistance degradation by photocatalysis)
An organic polymer composition masterbatch containing 20% silica-coated zinc oxide-containing powder was added to the diluted resin so that the silica-coated zinc oxide-containing powder was 1%, and 25 mm T-die film manufactured by Chuo Machinery Co., Ltd. A film having a thickness of 100 μm was obtained with a molding machine.
[0111]
This film was subjected to a weathering deterioration test by photocatalysis over 180 hours on a Sunshine Super Long Life Weather Meter WEL-SUN-HCH type manufactured by Suga Test Instruments Co., Ltd.
[0112]
Evaluation of weathering deterioration due to photocatalytic action is performed by measuring the haze of the film before and after being applied to the sunshine super long life weather meter with a reflection / transmittance meter HR-100 manufactured by Murakami Color Research Laboratory Co., Ltd. went. It can be determined that weather resistance deterioration due to photocatalytic action is suppressed when the change in haze is smaller.
[0113]
Example 1:
A 50 L reactor was mixed with 18.25 L of deionized water, 22.8 L of ethanol (manufactured by Junsei Chemical Co., Ltd.), and 124 mL of 25% by mass ammonia water (manufactured by Daisei Kako Co., Ltd.), and raw material zinc oxide particles (Showa Titanium) Suspension A was prepared by dispersing 1.74 kg of high-purity zinc oxide UFZ-40 (manufactured by Co., Ltd .; primary particle size 27 nm). Next, 1.62 L of tetraethoxysilane (GE Toshiba Silicone) and 1.26 L of ethanol were mixed to prepare a solution B.
[0114]
Solution B was added to the stirring suspension A at a constant rate over 9 hours and then aged for 12 hours. Film formation and aging were performed at 45 ° C. Then, solid content was isolate | separated by centrifugal filtration, and it vacuum-dried at 50 degreeC for 12 hours, and also dried with warm air at 80 degreeC for 12 hours. Subsequently, the silica-coated zinc oxide fine particles were obtained by crushing with a jet mill.
[0115]
When the transmission infrared absorption spectrum of the obtained silica-coated zinc oxide was measured by the KBr method, it was 1000 to 1200 cm.^-1The absorption derived from Si—O—Si stretching vibration was observed in 2800 to 3000 cm.^-1No absorption derived from C—H stretching vibration was observed, and the resulting coating was identified as silica.
[0116]
Furthermore, the primary particle diameter, the silica film thickness, the absorption peak intensity ratio I of the infrared absorption spectrum, the refractive index of the silica film, the photocatalytic activity by the tetralin auto-oxidation method, and the like were measured. The results are shown in Table 1.
[0117]
The dye fading rate of silica-coated zinc oxide fine particles by the tetralin auto-oxidation method is 0.1 (ΔABS₄₉₀/ Hour) or less, and the decomposition of the dye was suppressed to a low level as compared with the uncoated product and the commercially available zinc oxide.
[0118]
The decomposition rate of the organic ultraviolet absorber by the parasol 1789 method of silica-coated zinc oxide fine particles was 0.02 (ΔABS₃₄₀/ Hour), and the decomposability of the UV absorber was significantly lower than that of uncoated products and commercially available zinc oxide.
[0119]
The decomposition rate of the silica-coated zinc oxide fine particles was 5% or less, and the decomposability of the ultraviolet absorber was lower than that of uncoated products and commercially available zinc oxide.
[0120]
[Table 1]

Also, add 97 parts by mass of silica-coated zinc oxide with 3 parts by mass of methylene chloride solution of dimethylpolysiloxane (KF96-100CS, Shin-Etsu Chemical Co., Ltd.), and use a Henschel mixer (Mitsui Miike Mine Co., Ltd.) After mixing, the solvent was removed by vacuum drying at 90 ° C., and then the surface was hydrophobized at 200 ° C. for 6 hours to obtain a silica-coated zinc oxide having a hydrophobic surface. The content of coarse particles of 5 μm or more in the obtained silica-coated zinc oxide-containing powder was 1.6% by mass. The results of zinc ion dissolution are shown in Table 2.
[0121]
In the silica-coated zinc oxide of the present invention, elution of zinc ions was extremely suppressed compared with uncoated zinc oxide at various pHs, and was extremely low at 0.5 ppm or less in pure water. Furthermore, elution at various pHs was further suppressed by hydrophobizing the surface. Also in the organic polymer composition and its molded product, the effect of preventing the elution of zinc ions by contact with an acidic or alkaline solution can be sufficiently expected.
[0122]
[Table 2]

Further, the surface hydrophobized powder was subjected to dry precision classification using a turbo classifier (manufactured by Nissin Engineering Co., Ltd.). The content of coarse particles of 5 μm or more in the obtained silica-coated zinc oxide-containing powder was 0.02% by mass.
[0123]
20 parts of the silica-coated zinc oxide-containing powder thus obtained and 80 parts of polypropylene (PW600N manufactured by Sun Allomer Co., Ltd.) were mixed at 600 rpm for 3 minutes with a super mixer manufactured by Kawada Co., Ltd., and then manufactured by Nakaya Co., Ltd. The organic polymer composition master batch was obtained by kneading with a 30 mm different direction twin screw extruder.
[0124]
About the obtained organic polymer composition masterbatch, the moldability evaluation by a lab plast mill was performed on the temperature conditions of 230 (inlet) -230-230-230 degreeC. As shown in Table 3, the increase in the resin pressure was as low as 1.3 MPa, and the moldability was good.
[0125]
The obtained organic polymer composition master batch was diluted with PW600N manufactured by Sun Allomer Co., Ltd., and a weather resistance deterioration test by a photocatalytic action was performed.
[0126]
The haze of the film before being applied to the Sunshine Super Long Life Weather Meter was 18.2, the haze of the film after being applied was 18.6, the change in haze was as small as 0.4, and weathering deterioration due to photocatalysis was very small It was. From this, it can be seen that the obtained silica-coated zinc oxide fine particles have very little weathering deterioration due to the photocatalyst for polypropylene.
[0127]
Example 2:
In Example 1, instead of polypropylene (PW600N manufactured by Sun Allomer Co., Ltd.), the same operation as in Example 1 was performed except that polyethylene (JH607C manufactured by Nippon Polyolefin Co., Ltd.) was used, and an organic polymer composition masterbatch was prepared. Obtained.
[0128]
About the obtained organic polymer composition masterbatch, the moldability evaluation by Laboplast Mill was performed in the same manner as in Example 1. As a result, the increase in the resin pressure was as small as 0.7 MPa, and the moldability was good.
[0129]
Moreover, as a result of diluting with polyethylene (JH607C manufactured by Nippon Polyolefin Co., Ltd.) and conducting a weathering deterioration test due to photocatalytic action, the haze change was as small as 0.2, and the weathering deterioration due to photocatalytic action was very little.
From this, it can be seen that the obtained silica-coated zinc oxide fine particles have very little weathering deterioration due to the photocatalyst for polyethylene.
[0130]
Example 3:
In Example 1, instead of polypropylene (PW600N manufactured by Sun Allomer Co., Ltd.), the same operation as in Example 1 was performed, except that polyamide (AMS GM manufactured by EMS Showa Denko Co., Ltd.) was used. Got a batch.
[0131]
About the obtained organic polymer composition masterbatch, as a result of performing moldability evaluation by a lab plast mill in the same operation as in Example 1 except that the temperature condition was 270 (inlet) -270-270-270 ° C. The increase in pressure was as small as 2.1 MPa, and the moldability was good.
[0132]
Example 4:
In the synthesis of the silica-coated zinc oxide fine particles of Example 1, titanium oxide particles (high purity titanium oxide F-4 manufactured by Showa Titanium Co., Ltd., primary particle size 30 nm) were used instead of the raw material zinc oxide particles 1.74 Kg. Obtained silica-coated titanium oxide fine particles by the same synthesis method.
[0133]
Then, 94 parts by mass of the silica-coated titanium oxide was added 6 parts by mass of methylene chloride solution of dimethylpolysiloxane (KF96-100CS, Shin-Etsu Chemical Co., Ltd.), and a Henschel mixer (Mitsui Miike Mine Co., Ltd.) Then, the solvent was removed by vacuum drying at 90 ° C., followed by baking at 200 ° C. for 6 hours to obtain silica-coated titanium oxide having a hydrophobic surface.
[0134]
In the obtained silica-coated titanium oxide powder, the content of coarse particles of 5 μm or more was 1.5% by mass.
[0135]
Furthermore, the surface hydrophobized powder was subjected to dry precision classification using a turbo classifier (Nisshin Engineering Co., Ltd.). In the obtained silica-coated titanium oxide powder, the content of coarse particles of 5 μm or more was 0.02% by mass.
[0136]
Next, 30 parts by mass of the classified silica-coated titanium oxide powder and 70 parts by mass of the classified silica-coated zinc oxide powder of Example 1 were mixed and homogenized to obtain a silica-coated zinc oxide-containing powder. In the silica-coated zinc oxide-containing powder thus obtained, the content of coarse particles of 5 μm or more was 0.02% by mass.
[0137]
20 parts of silica-coated zinc oxide-containing powder and 80 parts of polypropylene (PW600N manufactured by Sun Allomer Co., Ltd.) were mixed at 600 rpm for 3 minutes with a super mixer manufactured by Kawada Co., Ltd. Were kneaded to obtain an organic polymer composition master batch.
[0138]
About the obtained organic polymer composition masterbatch, the moldability evaluation by Laboplast Mill was performed in the same manner as in Example 1. As a result, the resin pressure increase was as low as 1.0 MPa, and the moldability was good.
[0139]
Moreover, as a result of conducting the weathering deterioration test by a photocatalytic action similarly to Example 1 about the obtained organic polymer composition masterbatch, the change of haze is as small as 0.7 and the weathering deterioration by a photocatalytic action is very small. I understood it.
[0140]
Comparative Example 1:
In Example 1, the silica-coated zinc oxide-containing powder after classification was subjected to the same operation as in Example 1 except that the silica-coated zinc oxide-containing powder before classification was used to obtain an organic polymer composition master batch.
[0141]
About the obtained organic polymer composition masterbatch, the moldability was evaluated by Laboplast Mill by the same operation as in Example 1. As a result, the increase in the resin pressure was as large as 8.6 MPa, and the moldability was not good.
[0142]
However, the obtained organic polymer composition master batch was subjected to a weathering deterioration test by photocatalytic action in the same manner as in Example 1. The result was that the haze change of the film was as small as 0.5, and the weathering deterioration due to photocatalytic action was Very few.
From this, it can be seen that the obtained silica-coated zinc oxide fine particles have very little weathering deterioration due to the photocatalyst for polypropylene.
[0143]
Comparative Example 2:
The same operation as in Example 2 was performed except that the silica-coated zinc oxide-containing powder used in Comparative Example 1 was used to obtain an organic polymer composition master batch. About the obtained organic polymer composition masterbatch, the moldability was evaluated by Laboplast Mill by the same operation as in Example 2. As a result, the resin pressure increase was as large as 3.5 MPa, and the moldability was not good.
[0144]
However, the resulting organic polymer composition masterbatch was subjected to a weathering deterioration test by photocatalytic action in the same manner as in Example 2. The result was that the haze change of the film was as small as 0.3, and the weathering deterioration due to photocatalytic action was It was very small.
From this, it can be seen that the obtained silica-coated zinc oxide fine particles have very little weathering deterioration due to the photocatalyst for polyethylene.
[0145]
Comparative Example 3:
The same operation as in Example 3 was performed except that the silica-coated zinc oxide-containing powder used in Comparative Example 1 was used to obtain an organic polymer composition master batch. About the obtained organic polymer composition masterbatch, the moldability was evaluated by Laboplast Mill by the same operation as in Example 3. As a result, the increase in the resin pressure was as large as 15 MPa or more, and the moldability was not good.
[0146]
Comparative Example 4:
In Example 1, in place of the silica-coated zinc oxide-containing powder before hydrophobization, zinc oxide particles (high purity zinc oxide UFZ-40 manufactured by Showa Titanium Co., Ltd .; primary particle diameter 27 nm) were used, and Example 1 was used. The same operation was performed to obtain an organic polymer composition master batch. About the obtained organic polymer composition masterbatch, the moldability was evaluated by Laboplast Mill in the same manner as in Example 1. As a result, the resin pressure increase was as large as 4.2 MPa, and the moldability was not good.
[0147]
Moreover, as a result of conducting the weathering deterioration test by the photocatalytic action for the obtained organic polymer composition master batch in the same operation as in Example 1, the change in the haze of the film was as large as 8.2 and the weathering deterioration by the photocatalytic action It was big. From this,Not yetIt can be seen that the coated zinc oxide fine particles are greatly deteriorated in weather resistance due to the photocatalyst for polypropylene.
[0148]
Comparative Example 5:
In Example 2, in place of the silica-coated zinc oxide-containing powder before hydrophobization, zinc oxide particles (high purity zinc oxide UFZ-40 manufactured by Showa Titanium Co., Ltd .; primary particle diameter 27 nm) were used, and Example 2 was used. The same operation was performed to obtain an organic polymer composition master batch. About the obtained organic polymer composition masterbatch, the moldability was evaluated by Laboplast Mill in the same manner as in Example 2. As a result, the resin pressure increase was as large as 6.5 MPa, and the moldability was not good.
[0149]
The resulting organic polymer composition masterbatch was subjected to a weathering deterioration test by photocatalytic action in the same manner as in Example 2. As a result, the haze change of the film was as large as 6.5, and the weathering deterioration due to photocatalytic action was It was big. From this,Not yetIt can be seen that the coated zinc oxide fine particles are greatly deteriorated in weather resistance due to the photocatalyst for polyethylene.
[0150]
Comparative Example 6: An aqueous suspension (ZnO concentration: 50 g / L) of zinc oxide particles (High purity zinc oxide UFZ-40; manufactured by Showa Titanium Co., Ltd .; primary particle size: 27 nm) was heated to 80 ° C., and oxidized with stirring. For zinc, SiO ₂ As an aqueous solution of 10% by weight sodium silicate. After aging for 10 minutes, sulfuric acid was added with stirring over 60 minutes to neutralize to pH 6.5. After aging for 30 minutes, the resulting suspension was filtered, washed with water, and then dried by heating at 130 ° C. for 5 hours. The dried product thus obtained was jet mill pulverized to obtain silica-coated zinc oxide-containing powder. An organic polymer composition master batch was obtained by performing the same operation as in Example 1 except that this was used in place of the silica-coated zinc oxide fine particles before hydrophobic treatment in Example 1.
[0151]
About the obtained organic polymer composition masterbatch, the moldability was evaluated by Laboplast Mill by the same operation as in Example 1. As a result, the resin pressure increase was as small as 2.2 MPa, and the moldability was good.
[0152]
In addition, as a result of conducting a weathering deterioration test by photocatalytic action on the obtained organic polymer composition master batch in the same manner as in Example 1, the change in haze of the film was as large as 3.5, and the weathering deterioration by photocatalytic action was It was big. From this, it is understood that the obtained silica-coated zinc oxide fine particles are greatly deteriorated in weather resistance due to the photocatalyst for polypropylene.
[0153]
[Table 3]

【The invention's effect】
According to the present invention, there is no weathering deterioration due to photocatalysis, there is no bleeding out like an organic ultraviolet absorber, the durability against washing and the like is good, and a thin film or thin fiber having sufficient ultraviolet shielding ability A silica-coated zinc oxide-containing powder containing 5 μm or more coarse particles of 0.1% by mass or less, an organic polymer composition containing the same, and a molded product thereof are provided.

Claims (26)

The raw material zinc oxide particles are brought into contact with a composition for forming a silica film containing 1) a silicic acid containing no organic group and halogen or a precursor capable of producing the silicic acid, 2) water, 3) alkali, and 4) an organic solvent. A silica-coated zinc oxide-containing powder containing silica-coated zinc oxide fine particles whose surface is coated with silica, wherein coarse particles of 5 μm or more are 0.1% by mass or less. A powder containing silica-coated zinc oxide fine particles whose surface is hydrophobized by further subjecting silica-coated zinc oxide fine particles whose surface is coated with silica to surface treatment with a hydrophobicity-imparting agent, and coarse particles of 5 μm or more are 0 .Silica-coated zinc oxide-containing powder that is 1% by mass or less. The silica according to claim 2, wherein the hydrophobicity-imparting agent is one or more hydrophobicity-imparting agents selected from the group consisting of silicone oils, alkoxysilanes, silane coupling agents, and higher fatty acid salts. Coated zinc oxide-containing powder. The silica-coated zinc oxide-containing powder according to any one of claims 1 to 3, wherein the silica-coated zinc oxide fine particles have a silica film thickness of 0.5 to 100 nm. The silica-coated zinc oxide-containing powder according to any one of claims 1 to 4, wherein the primary particle diameter of the silica-coated zinc oxide fine particles is 1 to 200 nm. The silica-coated zinc oxide-containing powder according to claim 2 or 3, wherein the surface-hydrophobized silica-coated zinc oxide fine particles have a primary particle size of 5 to 120 nm and a silica film thickness of 0.5 to 25 nm. The ratio of the absorption peak intensity of the infrared absorption spectrum in 1150～1250Cm ^-1 and 1000～1100Cm ^-1 of the silica film of the silica-coated zinc oxide fine particles I (I = I1 / I2: I1 is the absorption peak intensity of 1150～1250Cm ^-1 The silica coating according to any one of claims 1 to 6, wherein I2 is an absorption peak intensity of 1000 to 1100 cm ^-1 ) is 0.2 or more, and the refractive index of the silica film is 1.435 or more. Zinc oxide-containing powder. The silica-coated zinc oxide-containing powder according to any one of claims 1 to 7, wherein the silica-coated zinc oxide-containing powder has a photocatalytic activity measured by a tetralin auto-oxidation method of 60 Pa / min or less. The silica-coated zinc oxide-containing powder according to any one of claims 1 to 8, wherein a dye fading rate (ΔABS ₄₉₀ / hour) measured by a sunset yellow method of the silica-coated zinc oxide-containing powder is 0.1 or less. . The silica-coated zinc oxide-containing powder according to any one of claims 1 to 9, wherein the decomposition rate of organic ultraviolet absorber (ΔABS ₃₄₀ / hour) measured by the parasol method of the silica-coated zinc oxide-containing powder is 0.01 or less. Powder. The silica-coated zinc oxide-containing powder according to any one of claims 1 to 10, wherein the silica-coated zinc oxide-containing powder has an organic ultraviolet absorber decomposition rate of 5% or less as measured by an ethylhexyl paramethoxycinnamate method. The silica-coated zinc oxide-containing powder according to any one of claims 1 to 11, wherein the silica-coated zinc oxide-containing powder contains titanium oxide. The silica-coated zinc oxide-containing powder according to claim 12, comprising 2 parts by mass to 5 parts by mass of titanium oxide with respect to 10 parts by mass of zinc oxide. The silica-coated zinc oxide-containing powder according to any one of claims 12 to 13, wherein at least a part of titanium oxide is coated with silica. The silica-coated zinc oxide-containing powder according to any one of claims 12 to 14, wherein the titanium oxide contains a mixed crystal in which a titanium-oxygen-silicon bond is present in primary particles. The silica according to claim 15, wherein the titanium oxide has a BET specific surface area of Am ² / g and a SiO ₂ content of B mass%, and B / A = 0.02 to 0.5. Coated zinc oxide-containing powder. 17. The silica-coated zinc oxide-containing powder according to claim 15, wherein the titanium oxide has a BET specific surface area of 10 to 200 m ² / g. 18. The silica-coated zinc oxide-containing powder according to claim 15, wherein a primary particle diameter of titanium oxide is 0.008 μm to 0.15 μm. 19. The titanium oxide has a core / shell structure, wherein the core has a TiO ₂ phase and the shell is rich in SiO ₂ phase. 2. Silica-coated zinc oxide-containing powder according to item 1. An organic polymer composition comprising the silica-coated zinc oxide-containing powder according to any one of claims 1 to 19 and a thermoplastic resin. An organic polymer composition comprising the silica-coated zinc oxide-containing powder according to any one of claims 1 to 19 and a thermoplastic resin. The organic polymer composition according to claim 20 or 21, wherein the thermoplastic resin is selected from polyethylene, polypropylene, polystyrene, polyamide, polyester, and polycarbonate. The molded object formed by shape | molding the organic polymer composition of any one of Claims 20 thru | or 22. The molded body according to claim 23, wherein the molded body is a molded body selected from fibers, yarns, films, tapes, sheets, hollow bodies, and multilayer structures. Interior and exterior building materials, machinery, vehicle interior and exterior materials, glass products, household appliances, agricultural materials, electronic equipment, tools, tableware, bath products, toilet articles, furniture, clothing, woven fabrics, non-woven fabrics, fabric products, leather products, paper products, At least one item selected from the group consisting of sports equipment, baskets, containers, glasses, signs, piping, wiring, metal fittings, sanitary materials, automotive goods, tents, outdoor equipment, stockings, socks, gloves, masks, and underwear An article comprising the molded article according to claim 23 or 24. A cosmetic comprising the silica-coated zinc oxide-containing powder according to any one of claims 1 to 19.