JP3952108B2 - Method for producing O / W emulsion - Google Patents

Description

（但し、上記式中、Ｒ¹〜Ｒ⁴のうち２個又は３個の基は無置換又は任意に上記官能基によって置換もしくは分断された炭素数１４〜２４の直鎖又は分岐したアルキル基又はアルケニル基を、Ｒ¹〜Ｒ⁴の残りの基は、炭素数１〜３のアルキル基、ヒドロキシアルキル基又は−（Ｃ₂Ｈ₄Ｏ）_nＨ（ｎは１〜５の整数）で表される基、Ｘはハロゲン又はＲ⁵ＳＯ₄（Ｒ⁵は炭素数１〜３のアルキル基を示す）で表されるモノアルキル硫酸基を示す。）
【００１５】
【化２】

（但し、上記式中、Ｒ⁶及びＲ⁷は、無置換又は任意に上記官能基によって置換もしくは分断された炭素数１４〜２４の直鎖又は分岐したアルキル基又はアルケニル基、Ｘはハロゲンを示す。）
【００１６】
【化３】

（但し、上記式中、Ｒ⁸は炭素数１〜４、好ましくは１又は２のアルキル基、Ｒ⁹及びＲ¹⁰は無置換又は任意に上記官能基によって置換もしくは分断された炭素数１４〜２４の直鎖又は分岐したアルキル基又はアルケニル基、Ｘは上記式（１）の場合と同じ意味を有する。）
【００１７】
これらのカチオン性乳化剤として、より具体的には、例えばジパーム油脂アルキルジメチルアンモニウムクロライド，ジ部分硬化パーム油脂アルキルジメチルアンモニウムクロライド，ジ硬化パーム油脂アルキルジメチルアンモニウムクロライド，ジ硬化牛脂アルキルジメチルアンモニウムクロライド，ジ牛脂アルキルジメチルアンモニウムブロマイド，ジオレイルジメチルアンモニウムクロライド，ジオレイルオキシエチルジメチルアンモニウムクロライド，ジパルミチルメチルヒドロキシエチルアンモニウムメチルサルフェート，ジステアリルメチルポリオキシエチレン（ＥＯ３）アンモニウムクロライド，ジイソステアリルジメチルアンモニウムメチルサルフェート，ジエイコシルジメチルアンモニウムクロライド，ジベヘニルメチルポリオキシエチレン（ＥＯ５）アンモニウムクロライド，ジエルシルジメチルアンモニウムクロライド，ジ［（２−ドデカノイルアミノ）エチル］ジメチルアンモニウムクロライド，ジ［（２−ステアロイルアミノ）プロピル］ジメチルアンモニウムエチルサルフェート，ジ（２−エチルパルミトイル）ヒドロキシエチルメチルアンモニウムメチルサルフェート，トリオレイルメチルアンモニウムクロライド，ジオレイルモノステアリルメチルアンモニウムクロライド，ジオレイルモノベヘニルメチルアンモニウムクロライド，モノオレイルジエルシルメチルアンモニウムクロライド，トリステアリルメチルアンモニウムメチルサルフェート，１−オクタデカノイルアミノエチル−２−ヘプタデシルイミダゾリン塩酸塩，１−オクタデセノイルアミノエチル−２−ヘプタデセニルイミダゾリン塩酸塩，メチル−１−牛脂アミドエチル−２−牛脂アルキルイミダゾリニウムメチルサルフェート，メチル−１−ヘキサデカノイルアミドエチル−２−ペンタデシルイミダゾリニウムクロライド，エチル−１−オクタデセノイルアミドエチル−２−ヘプタデセニルイミダゾリニウムエチルサルフェート等を挙げることができる。
【００１８】
アニオン性乳化剤としては、例えばポリオキシエチレンアルキルエーテル硫酸塩、ポリオキシエチレンアルキルエーテルリン酸塩、ポリオキシエチレンアルキルフェニルエーテルリン酸塩などが好適であり、より具体的には、ノニルフェニルエトキシサルフェートナトリウム，ポリオキシエチレン（ＥＯ５）ラウリルエーテル硫酸ナトリウム，ポリオキシエチレン（ＥＯ３）アルキル（炭素数１２，１３）エーテル硫酸ナトリウム，ポリオキシエチレン（ＥＯ２）ラウリルエーテル硫酸アンモニウム，ポリオキシエチレン（ＥＯ６．５）ノニルフェニルエーテルリン酸，ポリオキシエチレン（ＥＯ９．５）ノニルフェニルエーテルリン酸，ポリオキシエチレン（ＥＯ１５）ジアルキル（炭素数１２〜１５）フェニルエーテルリン酸，ポリオキシエチレン（ＥＯ３）セチルエーテルリン酸，ポリオキシエチレン（ＥＯ４）ラウリルエーテルリン酸，ポリオキシエチレン（ＥＯ６）アルキル（炭素数１２〜１５）エーテルリン酸，ポリオキシエチレン（ＥＯ４）オレイルエーテルリン酸ナトリウム，ポリオキシエチレン（ＥＯ４）ラウリルエーテルリン酸ナトリウム，ポリオキシプロピレン（ＰＯ２１）ブチルエーテルリン酸，ポリオキシプロピレン（ＰＯ４０）モノブチルエーテルリン酸等を挙げることができる。
【００１９】
非イオン性乳化剤としては、例えばポリオキシエチレンアルキルエーテル、脂肪酸ポリエチレングリコール、脂肪酸ポリオキシエチレンソルビタン、ポリグリセリン脂肪酸エステル、ポリオキシエチレンポリオキシプロピレングリコール、ポリオキシエチレングリセリン脂肪酸エステルなどを好適に使用することができ、具体的には、例えばポリオキシエチレン（ＥＯ４．２）ラウリルエーテル、ポリオキシエチレン（ＥＯ５．５）セチルエーテル、ポリオキシエチレン（ＥＯ１０）モノステアレート、ポリオキシエチレン（ＥＯ６）モノオレート、ポリオキシエチレン（ＥＯ６）ソルビタンモノステアレート、ヘキサグリセリルモノラウレート、デカグリセリルモノステアレート、デカグリセリルジステアレート、デカグリセリルモノイソステアレート、デカグリセリルジイソステアレート、ポリオキシエチレン（ＥＯ１）ポリオキシプロピレン（ＰＯ４）セチルエーテル、ポリオキシエチレン（ＥＯ５）グリセリルモノステアレート、ポリオキシエチレン（ＥＯ５）ノニルフェニルエーテル等を挙げることができる。
【００２０】
両性乳化剤としては、例えばアルキルベタイン、２−アルキルイミダゾリン誘導体、グリシンなどを好適に使用することができ、具体的には、例えばヤシ油脂肪酸アミドプロピルベタイン，ラウリルジメチルアミノ酢酸ベタイン，ラウリン酸アミドプロピルベタイン，２−アルキル−Ｎ−カルボキシエチル−Ｎ−ヒドロキシエチルイミダゾリニウムベタイン等を挙げることができる。
【００２１】
本発明の場合、これらの中でも上記非イオン性乳化剤、カチオン性乳化剤がより好適に使用され、特に上記非イオン性乳化剤がより好適に使用される。更に、高圧処理後の粘度増加をより顕著なものとするには、上記非イオン性乳化剤の中でもモノアルキル型のもののみを含むものよりもジアルキル型のものを含む乳化剤がより好ましく、この場合、２種以上の乳化剤を組み合わせてジアルキル型のものを含むようにしても良い。
【００２２】
上記液晶形成性乳化剤の配合量は、上記油性成分との合計配合量が本発明の範囲となる限り、乳化剤の種類等により適宜選定することができるが、通常Ｏ／Ｗ型エマルション全量に対して３〜４０％、特に１０〜３０％程度が望ましい。液晶形成性乳化剤の配合量が少なすぎると微細エマルションの形成が困難となる場合があり、配合量が多すぎるとゲル化して取り扱いが困難となる場合がある。
【００２３】
本発明のＯ／Ｗ型エマルションは、上記油性成分と上記液晶形成性乳化剤との合計配合量がＯ／Ｗ型エマルション全量に対して２５〜７０％であることが必要であり、好ましくは３０〜６５％、より好ましくは４０〜６０％である。油性成分と液晶形成性乳化剤との合計配合量が少なすぎると十分な増粘効果が得られず、合計配合量が多すぎると分散媒である水相量が少なくなってエマルションの形成が困難となる。
【００２４】
そして、上記油性成分と上記液晶形成性乳化剤との配合割合は、特に制限されるものではないが、油性成分：液晶形成性乳化剤（重量比）＝１：０．１〜１：１０、特に１：０．３〜１：３であることが望ましく、乳化剤の配合割合が大きすぎると油性成分の持つ効果に対して乳化剤の持つべとつき感が増し、商品価値が損なわれる場合がある。乳化剤の配合割合が小さすぎると微細エマルションを形成するのが困難となる場合がある。
【００２５】
本発明の油相は、上記油性成分及び液晶形成性乳化剤以外に、本発明の効果を妨げない限り、必要に応じて油溶性抗菌剤、油溶性防腐剤、油溶性香料等の添加剤を通常の配合量で配合することもできる。なお、これらの油溶性成分は、二次乳化工程時に配合することもでき、また、Ｏ／Ｗ型エマルション製品の用途等に合わせて二次乳化工程後に添加してもよい。
【００２６】
次に、本発明の水相は、水相成分として、水の他に本発明の効果を妨げない範囲で必要に応じて、各種水溶性有効成分等を通常の使用量で配合することができ、このような水溶性有効成分として、水溶性高分子化合物、後述する多価アルコール、低級アルコール、水溶性防腐剤、水溶性抗菌剤等を挙げることができ、これらは１種単独で又は２種以上を適宜組み合わせて使用することができる。
【００２７】
なお、これらの水溶性成分は、二次乳化工程時、二次乳化工程後にＯ／Ｗ型エマルション製品の用途等に合わせて配合することもできる。
【００２８】
ここで、上記水溶性高分子化合物としては、上記所定値以上の配合によって増粘作用を呈するものを挙げることができ、このような水溶性高分子化合物として、具体的には、例えばポリエチレングリコール、カルボキシビニルポリマー、カルボキシメチルセルロースナトリウム、ヒドロキシエチルセルロース、メチルセルロース、ヒドロキシプロピルセルロース、アルギン酸ナトリウム、デンプン、寒天、ゼラチン、ポリビニルアルコール、ポリアクリル酸ナトリウム、キサンタンガム、カラギーナン、ローカストビーンガム、アクリル酸メタクリル酸共重合体、カチオン化セルロース、プルラン、ペクチン等が挙げられ、これらは１種単独で又は２種以上を適宜組み合わせて使用することができる。
【００２９】
本発明のＯ／Ｗ型エマルションの場合、上記水溶性高分子化合物の配合量がエマルション全体に対して０．２％以下であることが必要であり、好ましくは０．１％以下、より好ましくは０．０５％以下である。水溶性高分子化合物の配合量が多すぎると、それ自身で系が増粘してしまい、本発明の目的を達成することができない。なお、水溶性高分子化合物の配合量の下限はなく、例えばエマルションの安定性をより向上させるなどの目的で水溶性高分子化合物を配合する必要がなければ、無配合であってもよい。
【００３０】
上記水相の配合量は、特に制限されるものではないが、上記油相との配合割合が油相：水相（重量比）＝２５：７５〜７０：３０、好ましくは３０：７０〜６５：３５、より好ましくは４０：６０〜６０：４０であることが望ましい。油相の配合割合が小さすぎると系の粘度が十分に上がらない場合があり、大きすぎると実質上粒子の細密充填を越えてしまい乳化ができない場合がある。
【００３１】
ここで、本発明の場合、上述したように多価アルコールは水相成分として好適に使用することができる他、本発明の製造方法において予備乳化物を調製するに当たり、上記油相と混合して上記油性成分を水相と混合する前に予め微滴化させるために使用しても好適であり、このような多価アルコールとしては、分子中に２個以上の水酸基を有するアルコールであればその種類が特に制限されるものではなく、例えば分子中に２〜６個の水酸基を有するアルコールを好適に使用することができ、より具体的には、例えばグリセリン、エチレングリコール、１，３−ブチレングリコール、ジプロピレングリコール、プロピレングリコール、イソプロピレングリコール、ソルビトール、１，４−ブチレングリコール、ヘキシレングリコール、１，５−ペンタンジオール等を挙げることができ、これらの中でも特にグリセリン、１，３−ブチレングリコール、ジプロピレングリコール、プロピレングリコール等がより好適に使用され、これらは１種単独で又は２種以上を適宜組み合わせて使用することができる。
【００３２】
なお、上記多価アルコールに上記油性成分を分散させた後、水相を混合して予備乳化工程を行う場合、この水相に更に多価アルコールが含有されていても良いのは勿論である。
【００３３】
上記多価アルコールの配合量は、その種類等によって適宜選定することができるが、予備乳化工程前に上記油相と混合して上記油性成分を予め微滴化させるために使用する場合、通常Ｏ／Ｗ型エマルション全量に対して３〜４０％、特に３〜３０％程度が望ましい。また、油相全体に対する配合量は、１０〜５０％、特に２５〜４０％程度が望ましい。多価アルコールの配合量が少なすぎると予備乳化工程前に油性成分を微滴化しておく効果が十分に得られない場合があり、配合量が多すぎると油相が分離して不均一になる場合がある。
【００３４】
なお、上記配合量は、予備乳化工程前に油相と混合するのに好適な多価アルコールの量であり、上述したように水相に多価アルコールを配合する場合、水相への配合量を含むものではなく、水相に多価アルコールを配合する場合、Ｏ／Ｗ型エマルション全量に対する多価アルコールの合計配合量は、５〜４０％、特に１０〜３０％程度となるように配合することが好ましい。
【００３５】
また、この場合、上記液晶形成性乳化剤との配合割合は、特に制限されるものではないが、乳化剤：多価アルコール（重量比）＝１：０．１〜１：２、特に１：０．５〜１：１．５であることが望ましく、上記範囲以外では微滴化が困難となる場合がある。なお、同様の理由により、上記油性成分との配合割合は、特に制限されるものではないが、油性成分：多価アルコール（重量比）＝１：０．１〜１：５、特に１：０．３〜１：２であることが望ましい。
【００３６】
そして、上記油性成分、液晶形成性乳化剤及び多価アルコールの合計配合量は、適宜選定することができるが、通常Ｏ／Ｗ型エマルション全量に対して、２５〜７０％、特に３０〜６０％程度が望ましい。合計配合量が少なすぎると十分な増粘効果が得られない場合があり、合計配合量が多すぎると分散媒の水相量が少なくなってエマルションの形成が困難となる場合がある。
【００３７】
本発明のＯ／Ｗ型エマルションは、エマルション粒子の平均粒子径が、０．１μｍ以下であり、好ましくは０．０１〜０．１μｍ、より好ましくは０．０１〜０．０５μｍであり、このような平均粒子径によって、エマルションの外観が透明乃至は半透明を呈することができる。
【００３８】
なお、本発明においてエマルション粒子の平均粒子径は、レーザードップラー方式の粒度分析計を用いて測定することが望ましい。
【００３９】
更に、本発明のＯ／Ｗ型エマルションは、２５℃における粘度が３〜８０Ｐａ・ｓの範囲にあることが必要であり、好ましくは５〜７０Ｐａ・ｓ、より好ましくは７〜６５Ｐａ・ｓである。粘度が低すぎると例えば化粧用クリーム等として使用する場合、本発明が目的とする皮膚への付着力が得られず、粘度が高すぎると固くなって変形させ難くなるなど取り扱い性が悪くなる。ここで、本発明において、上記粘度を測定する方法は、特に制限されるものではないが、例えば２５℃の温度条件下でＢＨ型粘度計を用いて、２０ｒｐｍ，１０回転目の値を用いて測定する方法が好適である。
【００４０】
本発明のＯ／Ｗ型エマルションは、平均粒子径が０．１μｍ以下というように非常に微細化されているので、きめが細かく、かつ艶がよい上にエマルション粒子の分離や凝集に対する安定性が良好であり、特に水溶性高分子化合物等を増粘剤として配合しなくても高い粘度を有するため、例えば化粧料用クリーム等として使用する場合、べたつきも少なく、使用感が良好であるのみならず、皮膚への付着性も良好なので、使用効果の高い化粧料を得ることができる。
【００４１】
本発明のＯ／Ｗ型エマルションの製造方法は、特に制限されるものでないが、上記油性成分及び液晶形成性乳化剤を含有する油相と上記水相とからなる系を混合して、水相中で油性成分を微細化してＯ／Ｗ型エマルションの予備乳化物を形成させる予備乳化工程と、上記予備乳化物を高圧ホモジナイザーを用いて二次乳化させて、油性成分をより一層微細化させると共に、系を増粘させる二次乳化（高圧乳化）工程とを行うことによって、予備乳化物の１０倍以上の粘度を有するＯ／Ｗ型エマルションを製造する本発明の製造方法によって製造すると、製造効率がよいので好適である。
【００４２】
ここで、本発明の製造方法の場合、上記予備乳化工程として、上記油相と上記多価アルコールとからなる系を混合して、多価アルコール中で油性成分を微滴化して例えば油性成分／多価アルコール型エマルションを調製する微滴化工程を行った後、上記分散液に水相を添加、混合して、連続相を上記多価アルコールを含む水相に転相させることによって予備乳化物を形成させる工程を採用すると、油性成分をより容易に微細化することができるので、より好適である。
【００４３】
以下、本発明の製造方法を、予備乳化工程と予備乳化工程における微滴化工程と二次乳化工程とに分けて説明する。
【００４４】
本発明の予備乳化工程は、上述したように油性成分及び液晶形成性乳化剤を含有する油相と水相とからなる系を混合して、油性成分を分散質の主体とする予備乳化物を形成するものである。ここで、油相を調製する際の諸条件は適宜選定されるが、上記油性成分と液晶形成性乳化剤とを均一に混合溶解させるには、油性成分に液晶形成性乳化剤を添加し、これらを６０〜９０℃、特に６５〜８０℃で混合溶解させることが望ましい。温度が低すぎると液晶形成性乳化剤の親水性が増して油性成分との混合溶解が困難となる場合があり、温度が高すぎると油性成分及び液晶形成性乳化剤が熱劣化しやすくなる場合がある。
【００４５】
ここで、本発明の油相調製工程における油性成分と液晶形成性乳化剤との混合溶解を行う装置は、特に制限されず、従来より使用されているパドルミキサー、プロペラミキサー、アジホモミキサー等のように高剪断羽根と掻き取り羽根とからなる撹拌機を備えた乳化釜などの撹拌装置を使用することができ、撹拌条件はこれら装置の通常の使用範囲にて行い、全体が均一に混合溶解するまで撹拌を続けることが望ましい。
【００４６】
なお、本発明において使用される乳化釜は温度コントロール機能を備えたものが望ましく、温度コントロール機能としては、具体的には、外部熱交換によるリサイクルライン、コイル、槽外側のジャケット等が挙げられるが、効率を考えるとこれらの中でもジャケットを用いることが好ましい。
【００４７】
次に、本発明の予備乳化工程は、上記油相と水相とを混合して、Ｏ／Ｗ型エマルションの予備乳化物を得るものであり、この場合、これらを添加する順序は特に制限されず、例えば全部を同時に添加することもでき、また、これらを加温する必要がある場合、その加温方法も特に制限されず、例えば油相と水相とを撹拌槽に仕込んだ後にこれらを同時に加温することもできるが、作業性を考慮すれば、予め油相は加温した状態にあるので、ここに所定温度に加温した水相を添加して、混合することが望ましい。
【００４８】
ここで、予備乳化物を調製する際の温度は、液晶形成性乳化剤の種類等によって適宜選定されるが、通常３０〜７０℃、より好ましくは３０〜６０℃が好適である。温度が低すぎると乳化が困難となったり、ゲル化する場合があり、高すぎると液晶形成性乳化剤の親水性が弱く、細かい粒子が形成できない場合がある。従って、上記油相を高い温度で溶解した場合は、水相と混合する際に、所定温度に冷却することが望ましい。
【００４９】
上記予備乳化物を調製する装置は、特に制限されず、従来より使用されている撹拌装置を使用することができるが、アジホモミキサー等の高剪断羽根と掻き取り羽根とを備えた乳化釜で行うことが好ましい。この際の撹拌条件は、これらの装置の通常の使用範囲にて行い、全体が均一な半透明状態又は白濁状態となるまで混合、撹拌を行うことが望ましい。なお、この工程において使用される撹拌槽（乳化釜）も上記油相調製工程と同様の温度コントロール機能を備えることが望ましい。
【００５０】
この予備乳化工程によって得られる予備乳化物は、２５℃における粘度が、３０〜２，０００ｍＰａ・ｓ、好ましくは５０〜１，０００ｍＰａ・ｓ、より好ましくは８０〜８００ｍＰａ・ｓが望ましく、平均粒子径は１０μｍ以下、好ましくは５μｍ以下、より好ましくは３μｍ以下となるように全体が均一に乳化されていることが望ましい。なお、上記予備乳化物の好適な平均粒子径の下限は特に制限されるものではなく、予備乳化工程で可能な限り微細化されていることが次の二次乳化工程の効率を良くする上で好ましい。
【００５１】
このような予備乳化物は、通常乳化、転相乳化，Ｄ相乳化等の種々の乳化方法によって得ることができるが、後述する微滴化工程によって、上記油性成分を予め微滴化させておく方法がより好適であり、より好ましくは、油性成分／多価アルコール型エマルション状態、即ち、予備乳化の途中で上記油性成分が上記液晶形成性乳化剤を介して多価アルコール中で粒子をつくるような系を通ってから水相と接触すると、微滴化効率の点で望ましい。
【００５２】
この微滴化工程は、上記油相と上記多価アルコールとを混合するものであり、この場合、添加順序、撹拌装置、撹拌条件は、上記予備乳化工程と同様であるが、この工程の場合、撹拌する際の温度は、油性成分を微滴化させる際の効率を考慮すると、上記油相調製工程の温度と同様であることが望ましい。
【００５３】
上記微滴化工程後に、上記水相を添加、混合することによって、油性成分が多価アルコール中に微滴化分散した例えば油／多価アルコール型エマルションのような分散液を転相させて、水相と多価アルコールとからなる連続相（分散媒）中に微細化した油滴粒子が分散した上記粘度及び平均粒子径のＯ／Ｗ型エマルションの予備乳化物を容易に得ることができる。なお、この分散工程を行った後、水相を添加する際には、上記と同様の理由により、分散液の温度を上記乳化工程の温度に冷却した後、水相と混合することが望ましい。
【００５４】
本発明の二次乳化工程は、上記予備乳化物を高圧ホモジナイザーを用いて高圧乳化することによって、予備乳化工程で微細化された油滴粒子を更に微細化すると共に、予備乳化物を増粘させて、予備乳化物の１０倍以上の粘度、好ましくは１０〜１，０００倍、より好ましくは２０〜８００倍の粘度を有するＯ／Ｗ型エマルションを調製するものであり、これによって本発明の上記Ｏ／Ｗ型エマルションを製造することができる。
【００５５】
この二次乳化工程で使用される高圧ホモジナイザーとしては、例えば５００ＭＰａ以上の高圧でホモジナイズできるものであれば、その種類は特に制限されず、具体的には、例えばゴーリンホモジナイザー（商品名、ＡＰＶ ラニー社製）、マイクロフルイダイザー（商品名、マイクロフルイデックス インターナショナル社製）、アルティマイザー（商品名、スギノマシン社製）、ナノマイザー（商品名、ナノマイザー社製）、ＮＳ型高圧ホモジナイザー（商品名、Ｎｉｒｏ−Ｓｏａｖｉ．Ｓ．ｐ．Ａ社製）等を挙げることができる。これらの装置を用いて高圧乳化する際の諸条件は適宜選定されるが、高圧ホモジナイザー圧力条件は、４０〜２５０ＭＰａ、特に７０〜２５０ＭＰａであることが望ましい。圧力が低すぎると予備乳化物を十分に増粘させることが困難となる場合があり、圧力が高すぎると発熱が激しくＯ／Ｗ型エマルションが解乳化する場合がある。
【００５６】
なお、高圧乳化時のエマルション温度は、例えば液晶形成性乳化剤として上記非イオン性乳化剤を使用する場合、曇点を持つものは高圧処理中であっても使用する乳化剤の曇点以下の温度が維持されるように処理前の系の温度を設定したり、高圧処理中のエマルション系が流動性を維持するような温度域で処理を行うなどというように乳化剤の種類やエマルション系の性質などに合わせて設定する必要があり、高圧処理によって系の温度は例えば１００ＭＰａで１回通過させることによって大体＋２５℃程上昇するので、通常、１０〜４０℃、特に２０〜３０℃とすることが望ましい。温度が低すぎると液の粘度が上昇し、流動性が悪くなる場合があり、高すぎると高圧乳化時の発熱によりエマルションが解乳化する場合がある。
【００５７】
本発明の二次乳化工程は、上記予備乳化工程で得られた予備乳化物を高圧ホモジナイザーを用いて、粘度が上記のように増加するまで数回通過させて増粘処理するものであり、通常、１〜２回通過させることによって、エマルション粘度を高圧処理前の１０倍以上に増大させることができる。
【００５８】
本発明の製造方法の場合、予め予備乳化工程で油滴粒子表面に液晶形成性乳化剤が集中的に配向しているので、高圧処理を行った際にもエマルションの分離や凝集に対する安定性に優れた超微粒子Ｏ／Ｗ型エマルションを得ることができ、更に、高分子化合物等を増粘剤として使用しなくても二次乳化工程によって増粘することができるので、上記のような高粘度で透明乃至は半透明の外観を呈する本発明のＯ／Ｗ型エマルションを容易に調製することが可能となる。なお、本発明の製造方法は、本発明のＯ／Ｗ型エマルション以外のＯ／Ｗ型エマルションであっても好適に製造することができるのは勿論である。
【００５９】
【発明の効果】
本発明のＯ／Ｗ型エマルションは、平均粒子径が０．１μｍ以下というように非常に微細化されているので、きめが細かく、艶もよい上に、エマルションの安定性も良好であり、水溶性高分子化合物などを増粘剤として使用しなくても所望の高粘度を有するので、べたつきも少なく、例えば化粧料用クリーム等として使用すると、使用感が良好で、皮膚への付着性、滞留性に優れ、適用効果が高い上、透明乃至は半透明の外観を呈するという特長を持つ化粧料を得ることができる。
【００６０】
従って、本発明のＯ／Ｗ型エマルションは、例えばクリーム，美容液等のスキンケア，フェイスケア製品などの皮膚用化粧料、毛髪用化粧料、リンス、トリートメント、衣料用仕上げ剤、医薬品液剤などの香粧品、医薬品、繊維処理製品等の各種分野の製品に好適に使用することができる。
【００６１】
そして、本発明の製造方法によれば、予備乳化物を調製した後、二次乳化工程によって増粘させるので、増粘剤によって増粘する方法と比較して高粘度Ｏ／Ｗ型エマルションを容易に製造することができるので、高粘度Ｏ／Ｗ型エマルションの製造方法として好適であり、特に本発明のＯ／Ｗ型エマルションを製造効率よく調製することができる。
【００６２】
【実施例】
以下、実施例及び比較例を示して本発明を具体的に説明するが、本発明は下記実施例に限定されるものではない。なお、以下の組成において％は、重量％を意味する。また、以下の例において、粘度はＢＨ型粘度計を用いて上述した方法で測定し、エマルションの平均粒子径は日機装（株）製の粒度分析計であるマイクロトラックＵＰＡを用いて測定した。
【００６３】

【００６４】
上記組成となるように油相の各成分をアジホモミキサーに仕込み、これらを７０℃で３０分間程度混合させて油相を調製し、この油相を６０℃付近まで冷却した後、予め上記水相の組成に従って調製して５０℃に保温しておいた水相と５０℃で１０分間混合して予備乳化物を調製した。この予備乳化物を２５℃まで冷却した後、マイクロフルイデックス インターナショナル株式会社製のマイクロフルイダイザーの処理圧力を１００ＭＰａとし、処理回数１回の条件で高圧乳化処理してＯ／Ｗ型エマルションを得た。
【００６５】
上記予備乳化物の粘度は８０ｍＰａ・ｓ（２５℃）であった。一方、高圧処理後の高粘度Ｏ／Ｗ型エマルションの粘度は７，４００ｍＰａ・ｓ（２５℃）、平均粒子径は０．１μｍ、外観は半透明であった。
【００６６】
上記高粘度Ｏ／Ｗ型エマルションは、一見するとゲルのように見えるが、水希釈により容易に分散した。これはこの高粘度エマルションの中に既にしっかりとしたＯ／Ｗ型エマルションが作られていることの証で、高分子化合物などにより粘度を出しているゲルとは全く異なった物であることが認められた。更に、偏光顕微鏡で上記Ｏ／Ｗ型エマルションを観察したところ、異方性が認められないことから、高粘度液晶状態でもないことが確認された。
【００６７】
また、得られたＯ／Ｗ型エマルションを５０℃で１ケ月間保存した後、及び室温で６ケ月間保存した後、それぞれ目視観察したところ、いずれの保存条件の場合であっても分離安定性は良好であることが認められた。
【００６８】

【００６９】
上記組成となるように油相の各成分をアジホモミキサーに仕込み、これらを７０℃で３０分間程度混合させて油相を調製し、この油相を５０℃付近まで冷却した後、予め上記水相の組成に従って調製して３５℃に保温しておいた水相と３５℃で１０分間混合して予備乳化物を調製した。この予備乳化物を２５℃まで冷却した後、マイクロフルイデックス インターナショナル株式会社製のマイクロフルイダイザーの処理圧力を１００ＭＰａとし、処理回数１回の条件で高圧乳化処理してＯ／Ｗ型エマルションを得た。
【００７０】
上記予備乳化物の粘度は５３５ｍＰａ・ｓ（２５℃）であった。一方、高圧処理後の高粘度Ｏ／Ｗ型エマルションの粘度は７，２００ｍＰａ・ｓ（２５℃）、平均粒子径は０．０１７μｍ、外観は透明であり、その他の性状は上記実施例１と同様であった。
【００７１】

【００７２】
上記組成となるように油相の各成分をアジホモミキサーに仕込み、これらを７０℃で３０分間程度混合させて油相を調製し、この油相を５０℃付近まで冷却した後、予め上記水相の組成に従って調製して３５℃に保温しておいた水相と３５℃で１０分間混合して予備乳化物を調製した。この予備乳化物を２５℃まで冷却した後、マイクロフルイデックス インターナショナル株式会社製のマイクロフルイダイザーの処理圧力を１００ＭＰａとし、処理回数１回の条件で高圧乳化処理してＯ／Ｗ型エマルションを得た。
【００７３】
上記予備乳化物の粘度は３４０ｍＰａ・ｓ（２５℃）であった。一方、高圧処理後の高粘度Ｏ／Ｗ型エマルションの粘度は８，５００ｍＰａ・ｓ（２５℃）、平均粒子径は０．０１５μｍ、外観は透明であり、その他の性状は上記実施例１と同様であった。
【００７４】

【００７５】
上記組成となるように油相の各成分をアジホモミキサーに仕込み、これらを７０℃で３０分間程度混合させて油相を調製し、この油相を６０℃付近まで冷却した後、予め上記水相の組成に従って調製して５０℃に保温しておいた水相と５０℃で２０分間混合して予備乳化物を調製した。この予備乳化物を２５℃まで冷却した後、マイクロフルイデックス インターナショナル株式会社製のマイクロフルイダイザーの処理圧力を１５０ＭＰａとし、処理回数１回の条件で高圧乳化処理してＯ／Ｗ型エマルションを得た。
【００７６】
上記予備乳化物の粘度は２２０ｍＰａ・ｓ（２５℃）であった。一方、高圧処理後の高粘度Ｏ／Ｗ型エマルションの粘度は５０，４００ｍＰａ・ｓ（２５℃）、平均粒子径は０．０４μｍ、外観は半透明であり、その他の性状は上記実施例１と同様であった。
【００７７】

【００７８】
上記組成となるように油相の各成分をアジホモミキサーに仕込み、これらを７０℃で３０分間程度混合させて油相を調製し、この油相を６０℃付近まで冷却した後、予め上記水相の組成に従って調製して４０℃に保温しておいた水相と４０℃で１０分間混合して予備乳化物を調製した。この予備乳化物を２５℃まで冷却した後、マイクロフルイデックス インターナショナル株式会社製のマイクロフルイダイザーの処理圧力を１２０ＭＰａとし、処理回数１回の条件で高圧乳化処理してＯ／Ｗ型エマルションを得た。
【００７９】
上記予備乳化物の粘度は１６０ｍＰａ・ｓ（２５℃）であった。一方、高圧処理後の高粘度Ｏ／Ｗ型エマルションの粘度は２３，６００ｍＰａ・ｓ（２５℃）、平均粒子径は０．０２５μｍ、外観は半透明であり、その他の性状は上記実施例１と同様であった。
【００８０】

【００８１】
上記組成となるように油相の各成分をアジホモミキサーに仕込み、これらを７０℃で３０分間程度混合させて油相を調製し、この油相を６０℃付近まで冷却した後、予め上記水相の組成に従って調製して５０℃に保温しておいた水相と５０℃で５分間混合して予備乳化物を調製した。この予備乳化物を２５℃まで冷却した後、マイクロフルイデックス インターナショナル株式会社製のマイクロフルイダイザーの処理圧力を１００ＭＰａとし、処理回数１回の条件で高圧乳化処理してＯ／Ｗ型エマルションを得た。
【００８２】
上記予備乳化物の粘度は１，５５０ｍＰａ・ｓ（２５℃）であった。一方、高圧処理後の高粘度Ｏ／Ｗ型エマルションの粘度は７０，０００ｍＰａ・ｓ（２５℃）、平均粒子径は０．０３μｍ、外観は半透明であり、その他の性状は上記実施例１と同様であった。
【００８３】

【００８４】
上記組成となるように油性成分、液晶形成性乳化剤及びその他の成分（プロピルパラベン）をアジホモミキサーに仕込み、これらを７５℃で３０分間程度、全体が目視によって均一と認められるまで混合溶解させ、次いで上記多価アルコールを添加して７５℃で５分間混合して油性成分／多価アルコール型エマルションを形成し、このエマルションを１５分間かけて５０℃まで冷却した後、予め上記水相の組成に従って調製しておいた水相を添加して５０℃で５分間混合してＯ／Ｗ型エマルションの予備乳化物を調製した。この予備乳化物を２５℃まで冷却した後、マイクロフルイデックス インターナショナル株式会社製のマイクロフルイダイザーの処理圧力を１１０ＭＰａとし、処理回数３回の条件で高圧乳化処理してＯ／Ｗ型エマルションを得た。
【００８５】
上記予備乳化物の粘度は６０ｍＰａ・ｓ（２５℃）であった。一方、高圧処理後の高粘度Ｏ／Ｗ型エマルションの粘度は５，０００ｍＰａ・ｓ（２５℃）、平均粒子径は０．０１８μｍ、外観は透明であり、その他の性状は上記実施例１と同様であった。
【００８６】

【００８７】
上記組成となるように油性成分及び液晶形成性乳化剤をアジホモミキサーに仕込み、これらを７０℃で３０分間程度、全体が目視によって均一と認められるまで混合溶解させ、次いで上記多価アルコールを添加して７０℃で５分間混合して油／多価アルコール型エマルションを形成し、このエマルションを１５分間かけて５０℃まで冷却した後、予め上記水相の組成に従って調製しておいた水相を添加して５０℃で５分間混合してＯ／Ｗ型エマルションの予備乳化物を調製した。この予備乳化物を２５℃まで冷却した後、マイクロフルイデックス インターナショナル株式会社製のマイクロフルイダイザーの処理圧力を７０ＭＰａとし、処理回数１１回の条件で高圧乳化処理してＯ／Ｗ型エマルションを得た。
【００８８】
上記予備乳化物の粘度は８００ｍＰａ・ｓ（２５℃）であった。一方、高圧処理後のＯ／Ｗ型エマルションの粘度は８０，０００ｍＰａ・ｓ（２５℃）、平均粒子径は０．０７μｍ、外観は半透明であり、その他の性状は上記実施例１と同様であった。
【００８９】

【００９０】
上記組成となるように油相の各成分をアジホモミキサーに仕込み、これらを７０℃で３０分間程度混合させて油相を調製し、この油相を５０℃まで冷却した後、予め上記水相の組成に従って調製して５０℃に保温しておいた水相と５０℃で１０分間混合して予備乳化物を調製した。この予備乳化物を２５℃まで冷却した後、マイクロフルイデックス インターナショナル株式会社製のマイクロフルイダイザーの処理圧力を１００ＭＰａとし、処理回数３回の条件で高圧乳化処理してＯ／Ｗ型エマルションを得た。
【００９１】
上記予備乳化物の粘度は１０ｍＰａ・ｓ（２５℃）であり、高圧処理後のＯ／Ｗ型エマルションは、粘度が１５ｍＰａ・ｓ（２５℃）、平均粒子径が０．０２５μｍ、外観は半透明であり、増粘されていないことだけが異なりその他の性状は上記実施例１と同様であった。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an O / W emulsion and a method for producing the same, and more specifically, a high-viscosity O / W emulsion excellent in emulsion stability without using a polymer compound or the like as a thickener, and the O / W The present invention relates to a method for producing an O / W emulsion capable of efficiently producing a type emulsion.
[0002]
[Prior art and problems to be solved by the invention]
Conventionally, various methods for producing an O / W emulsion have been proposed. In order to increase the viscosity of an O / W emulsion, it is proposed to add a water-soluble polymer compound or the like as a thickener. It had been.
[0003]
However, when a polymer compound is used as a thickening agent, a step of swelling the polymer compound is essential, and the swelling step greatly affects the production time or increases when the thickener is mixed into the system. In order to show the viscosity, it was a disadvantageous condition for the dispersion of the oily component and the kneading operation of the emulsion, and it was necessary to increase the temperature or devise the apparatus during the kneading.
[0004]
Further, when an O / W type emulsion composed of ultrafine particles having an average particle size of 0.1 μm or less, for example, is used as a cream for cosmetics or the like, a finely textured and glossy cream can be obtained. In this case, if the above emulsion has a high viscosity, it is easy to adhere to the skin when used, and the residual rate increases, and the effect on the skin due to the use of the emulsion increases. However, since the thickener originally has no effect on the skin, it is an extra component in terms of imparting effects on the skin.
[0005]
The present invention has been made in view of the above circumstances, and is an O / W type emulsion composed of ultrafine particles having a high viscosity even when not thickened by a polymer compound and the like and excellent in emulsion stability. A highly viscous O / W emulsion exhibiting a transparent or translucent appearance, and a method for producing an O / W emulsion capable of efficiently producing an O / W emulsion having such characteristics are provided. It is for the purpose.
[0006]
Means for Solving the Problem and Embodiment of the Invention
As a result of intensive studies to achieve the above object, the present inventor used a liquid crystal forming emulsifier as an emulsifier to be blended for forming an emulsion. First, the liquid crystal forming emulsifier and an oil component were used. After preparing the pre-emulsion of an O / W type emulsion by mixing the oil phase and the aqueous phase, the polymer compound is subjected to secondary emulsification using a high-pressure homogenizer, as shown in the examples described later. It has been found that a thickened O / W emulsion can be obtained without adding a thickener as a thickener. Further, in producing the preliminary emulsion, first, an oil phase and a polyhydric alcohol are mixed. Then, fine droplets of the oil component are dispersed in the polyhydric alcohol to obtain a dispersion such as an oil component / polyhydric alcohol emulsion, and then the aqueous phase is added to the continuous phase so that the above polyvalent Al By rotating the phase so that it becomes a water-containing aqueous solution, the oily component finely divided in the previous step is easily refined, and an O / W emulsion having a finer and uniform particle size is used as a preliminary emulsion. In addition, since the emulsifier is concentrated at the oil-water interface during the phase inversion in the preliminary emulsification step and the interfacial tension is further reduced, the liquid crystal forming emulsifier can be used even if the amount of the liquid crystal forming emulsifier is small. Even when the interfacial tension reducing ability is small, a pre-emulsion in which the oil component is refined with a low energy mechanical shearing force is obtained, and by further refinement, an O / W type comprising ultrafine particles It has been found that an emulsion can be prepared more easily, and the present invention has been made.
[0007]
That is, the present invention An oil phase containing an oily component and a liquid crystal-forming emulsifier and a polyhydric alcohol are mixed to disperse the oily component in the polyhydric alcohol to obtain a dispersion that is an oily component / polyhydric alcohol emulsion, and the dispersion An aqueous phase is added to and mixed with the liquid to prepare a pre-emulsion of an O / W emulsion using the oil component as a dispersoid and an aqueous phase and a polyhydric alcohol as a dispersion medium. A secondary emulsification using a homogenizer, having a viscosity of 10 times or more of the preliminary emulsion, The total amount of the oil component and the liquid crystal-forming emulsifier is 25 to 70% by weight of the whole emulsion, and the viscosity at 25 ° C. 5 O / W type emulsion having the above oil component as a dispersoid and having an average particle size of not more than 0.1 μm while having a viscosity of ˜80 Pa · s Manufacturing method I will provide a.
[0008]
Here, the polyhydric alcohol is added to the oil phase to disperse the oil component in the polyhydric alcohol, and then the aqueous phase is added to and mixed with the dispersion to invert the phase, whereby the O / W It is more preferable to prepare a pre-emulsion of the mold emulsion.
[0009]
Hereinafter, the present invention will be described in more detail. The O / W type emulsion of the present invention is obtained by mixing and emulsifying an oil phase and an aqueous phase containing an oil component and a liquid crystal forming emulsifier, and dispersing the oil component. The water-soluble polymer compound is a water phase containing a predetermined amount or less of the water-soluble polymer compound, and the liquid crystal-forming emulsifier is present at these interfaces. In the production method of the present invention, which will be described later, the water-soluble polymer compound need not necessarily be added to the aqueous phase to be added at the time of preparing the emulsion, and may be added after forming the emulsion.
[0010]
Here, as the oily component, hydrophobic oiliness used in products in various fields such as clothing finishes, cosmetics, pharmaceuticals, detergents, foods, etc., depending on the type and purpose of the O / W emulsion. Ingredients can be used, such as olive oil, palm oil, palm oil, olive squalane, jojoba oil, soybean oil, rice bran oil, cottonseed oil, corn oil and other vegetable oils, shark squalane Animal oils such as paraffin, mineral oils such as paraffin, isopropyl myristate, isopropyl palmitate, octyldodecyl myristate, polysiloxane, and the like. These may be used alone or in combination of two or more. Can be used.
[0011]
The blending amount of the oily component can be appropriately selected depending on the type of the oily component, the purpose of the O / W emulsion, and the use as long as the total blending amount with the liquid crystal forming emulsifier described below is within the scope of the present invention. Usually, 3 to 50% (% by weight, the same applies hereinafter), preferably 10 to 40%, more preferably about 15 to 30%, based on the total amount of the O / W emulsion. If the blending amount of the oil component is too small, the effect of blending the oil component may not be sufficiently obtained, and if the blend amount of the oil component is too large, the effect of blending the oil component reaches saturation, which is economically preferable. Absent.
[0012]
As the liquid crystal forming emulsifier of the present invention, any of the cationic, anionic, nonionic and amphoteric emulsifiers used in the above-mentioned various fields can be used, and these can be used alone. Or two or more kinds can be used in appropriate combination. Here, the liquid crystal forming property is such that when a small amount of water is added to the emulsifier and stirred, the liquid crystal is formed and the viscosity of the system is increased. The liquid crystal formed here is In most cases, the image can be viewed with a polarizing microscope.
[0013]
Examples of such liquid crystal-forming emulsifiers include, in the case of cationic emulsifiers, quaternary ammonium salts, imidazoline salts, imidazolinium salts, amine salts having a long-chain alkyl group or an alkenyl group. The long-chain alkyl group or alkenyl group of the quaternary ammonium salt may have a functional group such as —OH group bonded thereto, and the long-chain alkyl group or alkenyl group has a functional group such as —O—, —CONH—, or —COO—. Specifically, the quaternary ammonium salt is represented by the following general formula (1), and the imidazoline salt is represented by the following general formula (2). Examples of the linium salt include those represented by the following general formula (3).
[0014]
[Chemical 1]

(However, in the above formula, R ¹ ~ R ^Four 2 or 3 of the groups are unsubstituted or optionally substituted or divided by the above functional group, a straight or branched alkyl group or alkenyl group having 14 to 24 carbon atoms, R ¹ ~ R ^Four The remaining group is an alkyl group having 1 to 3 carbon atoms, a hydroxyalkyl group or-(C ₂ H _Four O) _n A group represented by H (n is an integer of 1 to 5), X is halogen or R ^Five SO _Four (R ^Five Represents a C1-C3 alkyl group). )
[0015]
[Chemical 2]

(However, in the above formula, R ⁶ And R ⁷ Is a linear or branched alkyl or alkenyl group having 14 to 24 carbon atoms which is unsubstituted or optionally substituted or divided by the above functional group, and X represents halogen. )
[0016]
[Chemical 3]

(However, in the above formula, R ⁸ Is an alkyl group having 1 to 4 carbon atoms, preferably 1 or 2, R ⁹ And R ^Ten Is a linear or branched alkyl or alkenyl group having 14 to 24 carbon atoms which is unsubstituted or optionally substituted or divided by the functional group, and X has the same meaning as in the above formula (1). )
[0017]
More specifically, as these cationic emulsifiers, for example, dipalm oil alkyldimethylammonium chloride, dipartially cured palm oil alkyldimethylammonium chloride, dicured palm oil alkyldimethylammonium chloride, dicured beef tallow alkyldimethylammonium chloride, di tallow Alkyldimethylammonium bromide, dioleyldimethylammonium chloride, dioleyloxyethyldimethylammonium chloride, dipalmitylmethylhydroxyethylammonium methylsulfate, distearylmethylpolyoxyethylene (EO3) ammonium chloride, diisostearyldimethylammonium methylsulfate, di Eicosyldimethylammonium chloride, dibehenylmethyl Lioxyethylene (EO5) ammonium chloride, dielsyldimethylammonium chloride, di [(2-dodecanoylamino) ethyl] dimethylammonium chloride, di [(2-stearoylamino) propyl] dimethylammonium ethyl sulfate, di (2-ethyl) Palmitoyl) hydroxyethylmethylammonium methylsulfate, trioleylmethylammonium chloride, dioleyl monostearylmethylammonium chloride, dioleylmonobehenylmethylammonium chloride, monooleyldielsylmethylammonium chloride, tristearylmethylammonium methylsulfate, 1-octadeca Noylaminoethyl-2-heptadecylimidazoline hydrochloride, 1-octadecenoy Aminoethyl-2-heptadecenylimidazoline hydrochloride, methyl-1-tallowamidoethyl-2-tallowalkylimidazolinium methylsulfate, methyl-1-hexadecanoylamidoethyl-2-pentadecylimidazolinium chloride, ethyl Examples include -1-octadecenoylamidoethyl-2-heptadecenylimidazolinium ethyl sulfate.
[0018]
As the anionic emulsifier, for example, polyoxyethylene alkyl ether sulfate, polyoxyethylene alkyl ether phosphate, polyoxyethylene alkyl phenyl ether phosphate and the like are preferable, and more specifically, nonylphenyl ethoxy sulfate sodium , Polyoxyethylene (EO5) sodium lauryl ether sulfate, polyoxyethylene (EO3) alkyl (carbon number 12, 13) sodium ether sulfate, polyoxyethylene (EO2) ammonium lauryl ether sulfate, polyoxyethylene (EO6.5) nonylphenyl Ether phosphoric acid, polyoxyethylene (EO9.5) nonylphenyl ether phosphoric acid, polyoxyethylene (EO15) dialkyl (C12-15) phenyl ether phosphoric acid, polyoxy Ethylene (EO3) cetyl ether phosphate, polyoxyethylene (EO4) lauryl ether phosphate, polyoxyethylene (EO6) alkyl (carbon number 12 to 15) ether phosphate, polyoxyethylene (EO4) sodium oleyl ether phosphate, Examples include polyoxyethylene (EO4) sodium lauryl ether phosphate, polyoxypropylene (PO21) butyl ether phosphate, polyoxypropylene (PO40) monobutyl ether phosphate, and the like.
[0019]
As the nonionic emulsifier, for example, polyoxyethylene alkyl ether, fatty acid polyethylene glycol, fatty acid polyoxyethylene sorbitan, polyglycerin fatty acid ester, polyoxyethylene polyoxypropylene glycol, polyoxyethylene glycerin fatty acid ester, etc. are preferably used. Specifically, for example, polyoxyethylene (EO4.2) lauryl ether, polyoxyethylene (EO5.5) cetyl ether, polyoxyethylene (EO10) monostearate, polyoxyethylene (EO6) monooleate, poly Oxyethylene (EO6) sorbitan monostearate, hexaglyceryl monolaurate, decaglyceryl monostearate, decaglyceryl distearate, decaglyceryl monoiso Examples include thearate, decaglyceryl diisostearate, polyoxyethylene (EO1) polyoxypropylene (PO4) cetyl ether, polyoxyethylene (EO5) glyceryl monostearate, polyoxyethylene (EO5) nonylphenyl ether, and the like. .
[0020]
As the amphoteric emulsifier, for example, alkylbetaines, 2-alkylimidazoline derivatives, glycine and the like can be suitably used. Specifically, for example, coconut oil fatty acid amidopropyl betaine, lauryldimethylaminoacetic acid betaine, lauric acid amidopropyl betaine , 2-alkyl-N-carboxyethyl-N-hydroxyethylimidazolinium betaine.
[0021]
In the present invention, among these, the nonionic emulsifier and the cationic emulsifier are more preferably used, and in particular, the nonionic emulsifier is more preferably used. Furthermore, in order to make the increase in viscosity after high-pressure treatment more remarkable, among the nonionic emulsifiers, an emulsifier containing a dialkyl type is more preferable than a non-emulsifier containing only a monoalkyl type, in this case, Two or more kinds of emulsifiers may be combined to include a dialkyl type.
[0022]
The blending amount of the liquid crystal-forming emulsifier can be appropriately selected depending on the type of emulsifier and the like as long as the total blending amount with the oil component is within the scope of the present invention, but is usually based on the total amount of the O / W emulsion. 3 to 40%, especially about 10 to 30% is desirable. If the blending amount of the liquid crystal-forming emulsifier is too small, it may be difficult to form a fine emulsion. If the blending amount is too large, gelation may occur and handling may be difficult.
[0023]
In the O / W type emulsion of the present invention, the total amount of the oil component and the liquid crystal forming emulsifier needs to be 25 to 70% with respect to the total amount of the O / W type emulsion, preferably 30 to 30%. 65%, more preferably 40-60%. If the total blending amount of the oil component and the liquid crystal-forming emulsifier is too small, a sufficient thickening effect cannot be obtained, and if the total blending amount is too large, the amount of the aqueous phase as a dispersion medium decreases and it is difficult to form an emulsion. Become.
[0024]
The mixing ratio of the oil component and the liquid crystal forming emulsifier is not particularly limited, but the oil component: liquid crystal forming emulsifier (weight ratio) = 1: 0.1 to 1:10, particularly 1. : 0.3 to 1: 3 is desirable, and if the blending ratio of the emulsifier is too large, the stickiness of the emulsifier increases with respect to the effect of the oil component, and the commercial value may be impaired. If the blending ratio of the emulsifier is too small, it may be difficult to form a fine emulsion.
[0025]
The oil phase of the present invention usually contains additives such as oil-soluble antibacterial agents, oil-soluble preservatives, and oil-soluble fragrances as necessary, as long as the effects of the present invention are not hindered, in addition to the oily components and liquid crystal forming emulsifiers. It can also mix | blend with the compounding quantity of. In addition, these oil-soluble components can also be mix | blended at the time of a secondary emulsification process, and may be added after a secondary emulsification process according to the use etc. of an O / W type emulsion product.
[0026]
Next, in the aqueous phase of the present invention, various water-soluble active ingredients and the like can be blended in normal amounts as necessary as long as the water phase component does not interfere with the effects of the present invention. Examples of such water-soluble active ingredients include water-soluble polymer compounds, polyhydric alcohols, lower alcohols, water-soluble preservatives, water-soluble antibacterial agents, and the like described below. The above can be used in appropriate combination.
[0027]
In addition, these water-soluble components can also be mix | blended according to the use etc. of O / W type emulsion product at the time of a secondary emulsification process and after a secondary emulsification process.
[0028]
Here, examples of the water-soluble polymer compound include those that exhibit a thickening action when blended to a predetermined value or higher. Specific examples of such a water-soluble polymer compound include polyethylene glycol, Carboxyvinyl polymer, sodium carboxymethylcellulose, hydroxyethylcellulose, methylcellulose, hydroxypropylcellulose, sodium alginate, starch, agar, gelatin, polyvinyl alcohol, sodium polyacrylate, xanthan gum, carrageenan, locust bean gum, methacrylic acid copolymer, Examples thereof include cationized cellulose, pullulan, and pectin. These can be used alone or in combination of two or more.
[0029]
In the case of the O / W emulsion of the present invention, the amount of the water-soluble polymer compound needs to be 0.2% or less, preferably 0.1% or less, more preferably, based on the whole emulsion. 0.05% or less. If the amount of the water-soluble polymer compound is too large, the system will thicken by itself and the object of the present invention cannot be achieved. In addition, there is no lower limit of the amount of the water-soluble polymer compound, and for example, if it is not necessary to blend the water-soluble polymer compound for the purpose of improving the stability of the emulsion, it may be unblended.
[0030]
The blending amount of the aqueous phase is not particularly limited, but the blending ratio with the oil phase is oil phase: water phase (weight ratio) = 25: 75 to 70:30, preferably 30:70 to 65. : 35, more preferably 40:60 to 60:40. If the blending ratio of the oil phase is too small, the viscosity of the system may not be sufficiently increased, and if it is too large, it may substantially exceed the fine packing of particles and emulsification may not be possible.
[0031]
Here, in the case of the present invention, as described above, the polyhydric alcohol can be suitably used as an aqueous phase component. In addition, in preparing the preliminary emulsion in the production method of the present invention, it is mixed with the oil phase. It is also preferable to use the oily component in advance for making fine droplets before mixing with the aqueous phase. As such a polyhydric alcohol, any alcohol having two or more hydroxyl groups in the molecule may be used. The type is not particularly limited, and for example, alcohol having 2 to 6 hydroxyl groups in the molecule can be preferably used. More specifically, for example, glycerin, ethylene glycol, 1,3-butylene glycol , Dipropylene glycol, propylene glycol, isopropylene glycol, sorbitol, 1,4-butylene glycol, hexylene glycol, 1,5 Pentanediol can be exemplified, and among these, glycerin, 1,3-butylene glycol, dipropylene glycol, propylene glycol and the like are more preferably used, and these are used alone or in appropriate combination of two or more. Can be used.
[0032]
In the case where the oil component is dispersed in the polyhydric alcohol and then the aqueous phase is mixed and the preliminary emulsification step is performed, the polyhydric alcohol may be further contained in the aqueous phase.
[0033]
The blending amount of the polyhydric alcohol can be appropriately selected depending on the type and the like, but when mixed with the oil phase before the pre-emulsification step and used to make the oily component fine droplets in advance, it is usually O / 3 to 40%, particularly about 3 to 30% is desirable with respect to the total amount of the W type emulsion. Moreover, the compounding quantity with respect to the whole oil phase is 10 to 50%, Especially about 25 to 40% is desirable. If the blending amount of the polyhydric alcohol is too small, there may be a case where the effect of micronizing the oily component before the preliminary emulsification step may not be sufficiently obtained. If the blending amount is too large, the oil phase is separated and becomes non-uniform. There is a case.
[0034]
In addition, the said compounding quantity is the quantity of the polyhydric alcohol suitable for mixing with an oil phase before a preliminary emulsification process, and when mix | blending a polyhydric alcohol with an aqueous phase as mentioned above, the compounding quantity to an aqueous phase When the polyhydric alcohol is blended in the aqueous phase, the total blending amount of the polyhydric alcohol with respect to the total amount of the O / W emulsion is 5 to 40%, particularly 10 to 30%. It is preferable.
[0035]
In this case, the blending ratio with the liquid crystal-forming emulsifier is not particularly limited, but emulsifier: polyhydric alcohol (weight ratio) = 1: 0.1 to 1: 2, particularly 1: 0. It is desirable that the ratio is 5 to 1: 1.5, and it may be difficult to make fine droplets outside the above range. For the same reason, the blending ratio with the oil component is not particularly limited, but the oil component: polyhydric alcohol (weight ratio) = 1: 0.1 to 1: 5, particularly 1: 0. .3 to 1: 2 is desirable.
[0036]
The total amount of the oil component, the liquid crystal-forming emulsifier and the polyhydric alcohol can be selected as appropriate, but is usually about 25 to 70%, particularly about 30 to 60% with respect to the total amount of the O / W emulsion. Is desirable. If the total blending amount is too small, a sufficient thickening effect may not be obtained, and if the total blending amount is too large, the aqueous phase amount of the dispersion medium may be reduced and it may be difficult to form an emulsion.
[0037]
In the O / W emulsion of the present invention, the average particle size of the emulsion particles is 0.1 μm or less, preferably 0.01 to 0.1 μm, more preferably 0.01 to 0.05 μm. Depending on the average particle size, the appearance of the emulsion can be transparent or translucent.
[0038]
In the present invention, the average particle size of the emulsion particles is preferably measured using a laser Doppler type particle size analyzer.
[0039]
Further, the O / W emulsion of the present invention needs to have a viscosity at 25 ° C. in the range of 3 to 80 Pa · s, preferably 5 to 70 Pa · s, more preferably 7 to 65 Pa · s. . When the viscosity is too low, for example, when it is used as a cosmetic cream or the like, the adhesive strength to the skin intended by the present invention cannot be obtained, and when the viscosity is too high, the handling property is deteriorated such that it becomes hard and difficult to deform. Here, in the present invention, the method for measuring the viscosity is not particularly limited. For example, using a BH type viscometer under a temperature condition of 25 ° C., using a value of 20 rpm and the 10th rotation. A measuring method is preferred.
[0040]
The O / W emulsion of the present invention is very fine so that the average particle size is 0.1 μm or less, so that it is fine and glossy and has stability against separation and aggregation of emulsion particles. Since it has a high viscosity even if it is not particularly blended with a water-soluble polymer compound as a thickener, for example, when it is used as a cream for cosmetics, it is less sticky and has a good feeling of use. Furthermore, since it has good adhesion to the skin, it is possible to obtain a cosmetic with a high use effect.
[0041]
The production method of the O / W type emulsion of the present invention is not particularly limited, but the system comprising the oil phase containing the oil component and the liquid crystal forming emulsifier and the water phase is mixed, In addition to the pre-emulsification step in which the oil component is refined to form a pre-emulsion of an O / W emulsion, the pre-emulsion is secondarily emulsified using a high-pressure homogenizer to further refine the oil component, When the production method of the present invention is used to produce an O / W emulsion having a viscosity 10 times or more that of the preliminary emulsion by performing a secondary emulsification (high pressure emulsification) step for thickening the system, production efficiency is improved. It is preferable because it is good.
[0042]
Here, in the case of the production method of the present invention, as the preliminary emulsification step, a system composed of the oil phase and the polyhydric alcohol is mixed, and the oily component is finely divided in the polyhydric alcohol, for example, oil component / Preliminary emulsified product by performing a microdropletization step for preparing a polyhydric alcohol type emulsion, and then adding and mixing an aqueous phase to the dispersion to invert the continuous phase to an aqueous phase containing the polyhydric alcohol. If the process of forming is employed, the oil component can be more easily refined, which is more preferable.
[0043]
Hereinafter, the production method of the present invention will be described by dividing it into a preliminary emulsification step, a microdropletization step in the preliminary emulsification step, and a secondary emulsification step.
[0044]
In the preliminary emulsification step of the present invention, as described above, a system composed of an oil phase and an aqueous phase containing an oil component and a liquid crystal-forming emulsifier is mixed to form a pre-emulsion mainly comprising the oil component as a dispersoid. To do. Here, various conditions for preparing the oil phase are appropriately selected. To uniformly mix and dissolve the oil component and the liquid crystal forming emulsifier, a liquid crystal forming emulsifier is added to the oil component. It is desirable to mix and dissolve at 60 to 90 ° C, particularly 65 to 80 ° C. If the temperature is too low, the hydrophilicity of the liquid crystal forming emulsifier may increase and mixing and dissolving with the oil component may be difficult. If the temperature is too high, the oil component and the liquid crystal forming emulsifier may be susceptible to thermal degradation. .
[0045]
Here, the apparatus for mixing and dissolving the oil component and the liquid crystal-forming emulsifier in the oil phase preparation step of the present invention is not particularly limited, and has been conventionally used, such as a paddle mixer, a propeller mixer, an adihomo mixer, etc. A stirrer such as an emulsifier equipped with a stirrer consisting of a high shear blade and a scraper blade can be used. Stirring conditions are within the normal use range of these devices, and the whole is uniformly mixed and dissolved. It is desirable to continue stirring until
[0046]
The emulsifying pot used in the present invention preferably has a temperature control function. Specific examples of the temperature control function include a recycle line by external heat exchange, a coil, and a jacket outside the tank. Among these, it is preferable to use a jacket in view of efficiency.
[0047]
Next, in the preliminary emulsification step of the present invention, the oil phase and the aqueous phase are mixed to obtain a preliminary emulsion of an O / W type emulsion. In this case, the order of adding these is particularly limited. For example, all of them can be added simultaneously, and when they need to be heated, the heating method is not particularly limited. For example, after adding the oil phase and the aqueous phase to the stirring tank, they are added. Although the oil phase can be heated at the same time, considering the workability, the oil phase is in a preheated state. Therefore, it is desirable to add and mix the water phase heated to a predetermined temperature.
[0048]
Here, the temperature at which the preliminary emulsion is prepared is appropriately selected depending on the type of liquid crystal-forming emulsifier and the like, but is usually 30 to 70 ° C, more preferably 30 to 60 ° C. If the temperature is too low, emulsification may be difficult or gel may occur, and if it is too high, the hydrophilicity of the liquid crystal forming emulsifier may be weak and fine particles may not be formed. Therefore, when the oil phase is dissolved at a high temperature, it is desirable to cool to a predetermined temperature when mixing with the aqueous phase.
[0049]
The apparatus for preparing the preliminary emulsion is not particularly limited, and a conventionally used stirring apparatus can be used. However, the pre-emulsified emulsion is an emulsification pot equipped with a high shear blade such as an Ajihomo mixer and a scraping blade. Preferably it is done. The stirring conditions at this time are preferably within the normal use range of these apparatuses, and it is desirable to mix and stir until the whole becomes a uniform translucent state or white turbid state. In addition, it is desirable for the stirring tank (emulsification pot) used in this step to have the same temperature control function as in the oil phase preparation step.
[0050]
The preliminary emulsion obtained by this preliminary emulsification step has a viscosity at 25 ° C. of 30 to 2,000 mPa · s, preferably 50 to 1,000 mPa · s, more preferably 80 to 800 mPa · s, and an average particle diameter. Is desirably uniformly emulsified so as to be 10 μm or less, preferably 5 μm or less, more preferably 3 μm or less. In addition, the minimum of the suitable average particle diameter of the said pre-emulsion is not restrict | limited in particular, In order to improve the efficiency of the following secondary emulsification process that it is refined | miniaturized as much as possible in the pre-emulsification process. preferable.
[0051]
Such a pre-emulsion can be obtained by various emulsification methods such as normal emulsification, phase inversion emulsification, D phase emulsification, etc., but the oil component is previously micronized by a micronization step described later. The method is more preferable, and more preferably, an oily component / polyhydric alcohol type emulsion state, that is, the oily component forms particles in the polyhydric alcohol via the liquid crystal forming emulsifier during the preliminary emulsification. Contact with the aqueous phase after passing through the system is desirable in terms of atomization efficiency.
[0052]
In this microdropletization step, the oil phase and the polyhydric alcohol are mixed. In this case, the order of addition, the stirring device, and the stirring conditions are the same as those in the preliminary emulsification step. The temperature at the time of stirring is preferably the same as the temperature in the oil phase preparation step in consideration of the efficiency in making the oily component into fine droplets.
[0053]
After the microdroplet step, the aqueous phase is added and mixed to phase-disperse a dispersion such as an oil / polyhydric alcohol emulsion in which the oil component is microdropped and dispersed in the polyhydric alcohol, It is possible to easily obtain a pre-emulsion of an O / W emulsion having the above-mentioned viscosity and average particle diameter in which fine oil droplet particles are dispersed in a continuous phase (dispersion medium) composed of an aqueous phase and a polyhydric alcohol. In addition, when adding an aqueous phase after performing this dispersion | distribution process, it is desirable to mix with the aqueous phase after cooling the temperature of a dispersion liquid to the temperature of the said emulsification process for the same reason as the above.
[0054]
In the secondary emulsification step of the present invention, the pre-emulsion is high-pressure emulsified using a high-pressure homogenizer to further refine the oil droplet particles refined in the pre-emulsification step and increase the viscosity of the pre-emulsion. Thus, an O / W emulsion having a viscosity 10 times or more that of the pre-emulsion, preferably 10 to 1,000 times, more preferably 20 to 800 times, is prepared. An O / W emulsion can be produced.
[0055]
The type of the high-pressure homogenizer used in the secondary emulsification step is not particularly limited as long as it can be homogenized at a high pressure of 500 MPa or more. Specifically, for example, a gorin homogenizer (trade name, APV Runny Co., Ltd.). ), Microfluidizer (trade name, manufactured by Microfluidics International), Optimizer (trade name, manufactured by Sugino Machine), Nanomizer (trade name, manufactured by Nanomizer), NS type high pressure homogenizer (trade name, Niro-) Soavi.SpA) and the like. Various conditions for high-pressure emulsification using these apparatuses are appropriately selected, but the high-pressure homogenizer pressure condition is preferably 40 to 250 MPa, particularly 70 to 250 MPa. If the pressure is too low, it may be difficult to sufficiently thicken the pre-emulsion, and if the pressure is too high, heat generation may be severe and the O / W emulsion may be de-emulsified.
[0056]
The emulsion temperature during high-pressure emulsification is, for example, when the above nonionic emulsifier is used as a liquid crystal forming emulsifier, those having a cloud point maintain the temperature below the cloud point of the emulsifier used even during high-pressure treatment. Set the temperature of the system before the treatment, and the emulsion system during the high-pressure treatment is processed in a temperature range that maintains fluidity, etc. Since the temperature of the system rises by about + 25 ° C. by passing it once at 100 MPa, for example, by high-pressure treatment, it is usually desirable to set it to 10 to 40 ° C., particularly 20 to 30 ° C. If the temperature is too low, the viscosity of the liquid increases and the fluidity may deteriorate, and if it is too high, the emulsion may be de-emulsified due to heat generated during high-pressure emulsification.
[0057]
In the secondary emulsification step of the present invention, the pre-emulsion obtained in the pre-emulsification step is passed through several times until the viscosity increases as described above, using a high-pressure homogenizer, By passing it once or twice, the emulsion viscosity can be increased to 10 times or more of that before the high-pressure treatment.
[0058]
In the case of the production method of the present invention, since the liquid crystal-forming emulsifier is intensively oriented on the surface of the oil droplet particles in the preliminary emulsification step in advance, the emulsion is excellent in stability against separation and aggregation even when subjected to high pressure treatment. In addition, it is possible to obtain an ultrafine O / W emulsion, and further, it can be thickened by the secondary emulsification step without using a polymer compound or the like as a thickening agent. It becomes possible to easily prepare the O / W type emulsion of the present invention exhibiting a transparent or translucent appearance. In addition, it cannot be overemphasized that the manufacturing method of this invention can manufacture suitably even if it is O / W type | mold emulsions other than the O / W type | mold emulsion of this invention.
[0059]
【The invention's effect】
The O / W type emulsion of the present invention is very fine so that the average particle size is 0.1 μm or less, so that it is fine and glossy, and the stability of the emulsion is also good. Even if a high molecular weight compound is not used as a thickening agent, it has a desired high viscosity, so there is little stickiness.For example, when used as a cosmetic cream, the feeling of use is good, and it adheres to the skin. It is possible to obtain a cosmetic material that has excellent properties, high application effects, and a transparent or translucent appearance.
[0060]
Therefore, the O / W type emulsion of the present invention has a fragrance such as skin care such as creams and cosmetic liquids, skin cosmetics such as face care products, hair cosmetics, rinses, treatments, finishing agents for clothes, and pharmaceutical liquids. It can be suitably used for products in various fields such as cosmetics, pharmaceuticals, and textile treatment products.
[0061]
According to the production method of the present invention, after preparing a pre-emulsion, it is thickened by the secondary emulsification step, so that it is easy to make a high viscosity O / W emulsion as compared with the method of thickening with a thickener. Therefore, it is suitable as a method for producing a high viscosity O / W emulsion, and in particular, the O / W emulsion of the present invention can be prepared with high production efficiency.
[0062]
【Example】
EXAMPLES Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated concretely, this invention is not limited to the following Example. In the following composition, “%” means “% by weight”. In the following examples, the viscosity was measured by the above-described method using a BH viscometer, and the average particle size of the emulsion was measured using Microtrac UPA, a particle size analyzer manufactured by Nikkiso Co., Ltd.
[0063]

[0064]
Each component of the oil phase is charged into an Ajihomo mixer so as to have the above composition, and these are heated at 70 ° C. for about 30 minutes. Mixed After the oil phase is cooled to around 60 ° C., it is preliminarily mixed with the aqueous phase prepared in advance according to the composition of the aqueous phase and kept at 50 ° C. for 10 minutes at 50 ° C. An emulsion was prepared. After this preliminary emulsion was cooled to 25 ° C., the treatment pressure of a microfluidizer manufactured by Microfluidics International Co., Ltd. was set to 100 MPa, and high-pressure emulsification treatment was performed under the conditions of one treatment, thus obtaining an O / W emulsion. .
[0065]
The preliminary emulsion had a viscosity of 80 mPa · s (25 ° C.). On the other hand, the viscosity of the high-viscosity O / W emulsion after the high-pressure treatment was 7,400 mPa · s (25 ° C.), the average particle size was 0.1 μm, and the appearance was translucent.
[0066]
The high-viscosity O / W emulsion looks like a gel at first glance, but was easily dispersed by dilution with water. This is a proof that a solid O / W emulsion has already been made in this high-viscosity emulsion. It was. Furthermore, when the O / W type emulsion was observed with a polarizing microscope, no anisotropy was observed, confirming that it was not in a high-viscosity liquid crystal state.
[0067]
The obtained O / W emulsion was stored at 50 ° C. for 1 month and stored at room temperature for 6 months and then visually observed. Was found to be good.
[0068]

[0069]
Each component of the oil phase is charged into an Ajihomo mixer so as to have the above composition, and these are heated at 70 ° C. for about 30 minutes. Mixed After the oil phase is cooled to around 50 ° C., it is preliminarily mixed with the aqueous phase prepared in advance according to the composition of the aqueous phase and kept at 35 ° C. for 10 minutes at 35 ° C. An emulsion was prepared. After this preliminary emulsion was cooled to 25 ° C., the treatment pressure of a microfluidizer manufactured by Microfluidics International Co., Ltd. was set to 100 MPa, and high-pressure emulsification treatment was performed under the conditions of one treatment, thus obtaining an O / W emulsion. .
[0070]
The preliminary emulsion had a viscosity of 535 mPa · s (25 ° C.). On the other hand, the viscosity of the high-viscosity O / W emulsion after high-pressure treatment is 7,200 mPa · s (25 ° C.), the average particle size is 0.017 μm, the appearance is transparent, and other properties are the same as in Example 1 above. Met.
[0071]

[0072]
Each component of the oil phase is charged into an Ajihomo mixer so as to have the above composition, and these are heated at 70 ° C. for about 30 minutes. Mixed After the oil phase is cooled to around 50 ° C., it is preliminarily mixed with the aqueous phase prepared in advance according to the composition of the aqueous phase and kept at 35 ° C. for 10 minutes at 35 ° C. An emulsion was prepared. After this preliminary emulsion was cooled to 25 ° C., the treatment pressure of a microfluidizer manufactured by Microfluidics International Co., Ltd. was set to 100 MPa, and high-pressure emulsification treatment was performed under the conditions of one treatment, thus obtaining an O / W emulsion. .
[0073]
The viscosity of the preliminary emulsion was 340 mPa · s (25 ° C.). On the other hand, the viscosity of the high-viscosity O / W emulsion after high-pressure treatment is 8,500 mPa · s (25 ° C.), the average particle size is 0.015 μm, the appearance is transparent, and other properties are the same as in Example 1 above. Met.
[0074]

[0075]
Each component of the oil phase is charged into an Ajihomo mixer so as to have the above composition, and these are heated at 70 ° C. for about 30 minutes. Mixed After the oil phase is cooled to around 60 ° C., it is preliminarily mixed with the aqueous phase prepared in advance according to the composition of the aqueous phase and kept at 50 ° C. for 20 minutes at 50 ° C. An emulsion was prepared. After this preliminary emulsion was cooled to 25 ° C., the treatment pressure of a microfluidizer manufactured by Microfluidics International Co., Ltd. was set to 150 MPa, and high-pressure emulsification treatment was performed under the conditions of one treatment. Thus, an O / W emulsion was obtained. .
[0076]
The viscosity of the preliminary emulsion was 220 mPa · s (25 ° C.). On the other hand, the viscosity of the high-viscosity O / W emulsion after the high-pressure treatment is 50,400 mPa · s (25 ° C.), the average particle size is 0.04 μm, the appearance is translucent, and the other properties are the same as in Example 1. It was the same.
[0077]

[0078]
Each component of the oil phase is charged into an Ajihomo mixer so as to have the above composition, and these are heated at 70 ° C. for about 30 minutes. Mixed After the oil phase is cooled to around 60 ° C., it is preliminarily mixed with the aqueous phase previously prepared according to the composition of the aqueous phase and kept at 40 ° C. for 10 minutes at 40 ° C. An emulsion was prepared. After this preliminary emulsion was cooled to 25 ° C., the treatment pressure of a microfluidizer manufactured by Microfluidics International Co., Ltd. was set to 120 MPa, and high-pressure emulsification treatment was performed under the conditions of one treatment, to obtain an O / W type emulsion. .
[0079]
The viscosity of the preliminary emulsion was 160 mPa · s (25 ° C.). On the other hand, the viscosity of the high-viscosity O / W emulsion after high-pressure treatment is 23,600 mPa · s (25 ° C.), the average particle size is 0.025 μm, the appearance is translucent, and the other properties are the same as in Example 1 above. It was the same.
[0080]

[0081]
Each component of the oil phase is charged into an Ajihomo mixer so as to have the above composition, and these are heated at 70 ° C. for about 30 minutes. Mixed After the oil phase is cooled to around 60 ° C, it is preliminarily mixed with the aqueous phase prepared in advance according to the composition of the aqueous phase and kept at 50 ° C for 5 minutes at 50 ° C. An emulsion was prepared. After this preliminary emulsion was cooled to 25 ° C., the treatment pressure of a microfluidizer manufactured by Microfluidics International Co., Ltd. was set to 100 MPa, and high-pressure emulsification treatment was performed under the conditions of one treatment, thus obtaining an O / W emulsion. .
[0082]
The preliminary emulsion had a viscosity of 1,550 mPa · s (25 ° C.). On the other hand, the viscosity of the high-viscosity O / W emulsion after high-pressure treatment is 70,000 mPa · s (25 ° C.), the average particle size is 0.03 μm, the appearance is translucent, and the other properties are the same as in Example 1 above. It was the same.
[0083]

[0084]
Oil components, liquid crystal-forming emulsifiers and other components (propylparaben) are charged into the adihomomixer so as to have the above composition, and these are mixed and dissolved at 75 ° C. for about 30 minutes until the whole is visually confirmed to be uniform, Next, the polyhydric alcohol is added and mixed at 75 ° C. for 5 minutes to form an oily component / polyhydric alcohol type emulsion. The emulsion is cooled to 50 ° C. over 15 minutes, and then preliminarily according to the composition of the aqueous phase. The prepared aqueous phase was added and mixed at 50 ° C. for 5 minutes to prepare an O / W emulsion pre-emulsion. After cooling this preliminary emulsion to 25 ° C., the treatment pressure of a microfluidizer manufactured by Microfluidics International Co., Ltd. was set to 110 MPa, and high-pressure emulsification treatment was performed under the conditions of three treatments to obtain an O / W type emulsion. .
[0085]
The viscosity of the preliminary emulsion was 60 mPa · s (25 ° C.). On the other hand, the viscosity of the high-viscosity O / W emulsion after high-pressure treatment is 5,000 mPa · s (25 ° C.), the average particle size is 0.018 μm, the appearance is transparent, and other properties are the same as in Example 1 above. Met.
[0086]

[0087]
Add oil component and liquid crystal forming emulsifier to Ajihomo mixer so as to have the above composition, mix and dissolve them at 70 ° C. for about 30 minutes until the whole is visually confirmed to be uniform, then add the above polyhydric alcohol. Mix for 5 minutes at 70 ° C. to form an oil / polyhydric alcohol emulsion, cool the emulsion to 50 ° C. over 15 minutes, then add the aqueous phase prepared in advance according to the composition of the aqueous phase above Then, a pre-emulsion of O / W type emulsion was prepared by mixing at 50 ° C. for 5 minutes. After this preliminary emulsion was cooled to 25 ° C., the treatment pressure of a microfluidizer manufactured by Microfluidics International Co., Ltd. was set to 70 MPa, and high-pressure emulsification treatment was performed under conditions of 11 treatments to obtain an O / W type emulsion. .
[0088]
The preliminary emulsion had a viscosity of 800 mPa · s (25 ° C.). On the other hand, the viscosity of the O / W emulsion after the high-pressure treatment is 80,000 mPa · s (25 ° C.), the average particle size is 0.07 μm, the appearance is translucent, and the other properties are the same as in Example 1 above. there were.
[0089]

[0090]
Each component of the oil phase is charged into an Ajihomo mixer so as to have the above composition, and these are heated at 70 ° C. for about 30 minutes. Mixed After the oil phase is cooled to 50 ° C., it is preliminarily emulsified by mixing for 10 minutes at 50 ° C. with the aqueous phase prepared in advance according to the composition of the aqueous phase and kept at 50 ° C. A product was prepared. After this preliminary emulsion was cooled to 25 ° C., the treatment pressure of a microfluidizer manufactured by Microfluidics International Co., Ltd. was set to 100 MPa, and high-pressure emulsification treatment was performed under the conditions of three treatments to obtain an O / W type emulsion. .
[0091]
The preliminary emulsion has a viscosity of 10 mPa · s (25 ° C.), and the O / W emulsion after the high-pressure treatment has a viscosity of 15 mPa · s (25 ° C.), an average particle size of 0.025 μm, and the appearance is translucent. The other properties were the same as in Example 1 except that the viscosity was not increased.

Claims (2)

An oil phase containing an oil component and a liquid crystal-forming emulsifier and a polyhydric alcohol are mixed to disperse the oil component in the polyhydric alcohol to obtain a dispersion that is an oil component / polyhydric alcohol emulsion, and the dispersion An aqueous phase is added to and mixed with the liquid to prepare a pre-emulsion of an O / W emulsion using the oil component as a dispersoid and an aqueous phase and a polyhydric alcohol as a dispersion medium. A secondary emulsification using a homogenizer has a viscosity 10 times or more that of the pre-emulsion, and the total amount of the oil component and the liquid crystal-forming emulsifier is 25 to 70% by weight of the whole emulsion. And a viscosity of 5 to 80 Pa · s at 25 ° C., and an average particle size of the emulsion is 0.1 μm or less, and a method for producing an O / W emulsion using the oil component as a dispersoid . The method for producing an O / W emulsion according to claim 1, wherein the amount of the polyhydric alcohol added to the entire oil phase is 10 to 50% by mass.