JP3812604B2 - pH buffering / humidifying polymer, method for producing the same, and sheet or cosmetic containing the polymer - Google Patents

Description

【００５３】
実施例 ２
メタクリル酸／p−スチレンスルホン酸ソーダ＝７０／３０の水溶性重合体３００部及び硫酸ナトリウム３０部を６５９５部の水に溶解し、櫂型撹拌機付きの重合槽に仕込んだ。次にアクリロニトリル（ＡＮ）２７００部及びアクリル酸メチル３００部に2，2’−アゾビスー（２，４−ジメチルバレロニトリル）１５部を溶解して重合槽に仕込み、４００ｒｐｍの撹件条件下、６０℃で２時間重合し、重合率８７％で平均粒子径５２μｍの高ニトリル系重合体を得た。該重合体１００部に６０重量％ヒドラジン５０部および水８５０部を混合し、９０℃、３時間の条件でヒドラジン処理を行うことにより架橋を導入し、さらに、１００部の苛性ソーダを添加し、１２０℃、２時間反応を行うことにより、残ニトリル基のすべてを加水分解しカルボン酸基（加水分解反応終了時点ではナトリウム型）を導入した。得られた重合体を水中に分散し、硝酸によりｐＨを６．５としたのち、硝酸カルシウムを添加し、６０℃、２時間金属塩処理を行ない、洗浄、脱水、乾燥しｐＨ緩衝・調湿性重合体微粒子を得た。該微粒子の特性を表１にまとめる。この結果にみられるとおり、該重合体微粒子は優れたｐＨ緩衝性および調湿性を有していることが確認できた。
【００５４】
実施例 ３
アクリロニトリル４５０部、アクリル酸メチル５０部及び水１１８１部を２リットルのオートクレイブ内に仕込み、更に重合開始剤としてジーｔｅｒｔ−ブチルパーオキサイドを単量体全量に対して０．５重量％添加した後、密閉し、次いで撹拌下において１２０℃の温度にて３０分間重合せしめた。反応終了後、撹拌を継続しながら約９０℃まで冷却することにより平均粒子径が３８μｍの凝集体微粒子分散液を得た。この凝集体微粒子の１次粒子を電子顕微鏡で観察したところ平均粒子径が０．３μmであった。得られた凝集体微粒子は実施例２と同様な方法により、ヒドラジン架橋および加水分解を行い、さらにｐＨ調整処理を行うことによりｐＨ緩衝・調湿性重合体微粒子を得た。該微粒子の特性を表１にまとめる。この結果にみられるとおり、該重合体微粒子は優れたｐＨ緩衝性および調湿性を有していることが確認できた。また、実施例２に比べてｐＨ緩衝性および調湿性が優れており、またｐＨ緩衝の作用する速度、および調湿性の平衡に達するまでの速度が実施例２に比べて優れていた。これは、実施例３が微小粒子の凝集体状であることより、表面積が大きくなったことおよび１次粒子間の空間が水分等の拡散に有効に働き、これらが良い結果を与えたものと考えられる。
【００５５】
実施例 ４
スチレン／ジビニルベンゼンをポリマー骨格とし、スルホン酸基を極性基として有する三菱化学製強酸性イオン交換樹脂「ＤＩＡＩＯＮ ＳＫ １Ｂ」を用い、実施例１と同様な方法により、ｐＨ調整処理を行うことによりｐＨ緩衝・調湿性重合体微粒子を得た。該微粒子の特性を表１にまとめる。この結果にみられるとおり、該重合体微粒子はｐＨ緩衝性および調湿性を有していることが確認できたが、その効果は実施例１から３にくらべやや劣るものであった。これは、粒子径が大きいこと、およびイオン交換容量が低いことよりこのような結果となったと考えられる。
【００５６】
実施例 ５
針葉樹パルプと広葉樹パルプを７：３の重量比で混合し、カナダ標準ろ水度が３６０ｃｃとなるように叩解した。このパルプを水に分散させ、濃度０．３重量％のパルプスラリーを調製し、実施例３で得られたｐＨ緩衝・調湿性重合体微粒子を濃度０．７重量％添加し、ＪＩＳ−Ｐ８２０９に準拠して抄紙した。得られた製品紙の該微粒子の含有率は、７０重量％、坪量は８５ｇ／ｍ２であった。得られた紙について、ｐＨ緩衝および調湿性を評価した結果を表２に示す。表にみられるとおり、得られた紙についても良好なｐＨ緩衝および調湿性が認められ、原料微粒子の能力が良く発現されていることが確認された。
【００５７】
【表２】

【００５８】
実施例 ６
５デニールのポリプロピレン繊維でなる目付け量８０ｇ ／ｍ２のネツト状不織布の上面に、２０ｇ／ｍ２の目の粗いホツトメルト不織布を載置し、その上面に実施例３で得られたｐＨ緩衝・調湿性重合体微粒子を６０ｇ／ｍ２の分量でふりかけ、加熱して接合させることにより、ｐＨ緩衝・調湿性重合体微粒子を含有した不織布を得た。該不織布は、通気性が高く、ｐＨ緩衝・調湿性重合体微粒子の層を良く保持したものであった。また、そのｐＨ緩衝および調湿性についても表２に示される通り良好であり、実施例５と同様、原料微粒子の能力が良く発現されていることが確認できた。
【００５９】
実施例 ７
同じく実施例３で得られたｐＨ緩衝・調湿性重合体微粒子を、下記処方によりウレタン樹脂に混合し、混合物を離型紙上に流延して乾式発泡させ、該微粒子を合有する発泡ウレタンシートを作製した。
ウレタン樹脂１００部（ＵＦ−３Ａ、セイコー化成製）
充填剤１０部（ＦＡＤ一３０、セイコー化成製）
発泡剤１部（ＦＡＤ−３１、セイコー化成製）
ｐＨ緩衝・調湿性重合体微粒子１３部
上記組成の薬剤をディスパーで３０分撹拌してよく混合し、離型紙上に厚み約０．１５ｍｍに流延し、１３０℃で２分間キュアリングして発泡させた。出来上がり発泡シート厚みは０．５ｍｍであった。この発泡ウレタンシートは１ｍ２あたり約１０ｇのｐＨ緩衝・調湿性重合体微粒子を合有していた。
【００６０】
得られたウレタンシートのｐＨ緩衝および調湿性の評価結果は表２にまとめた。該表に示される通り、該ウレタンシートは良好なｐＨ緩衝および調湿性が認められ、原料微粒子の能力が良く発現されていることが確認できた。さらに該ウレタンシートにおいては、該重合体の保持性も良好で、各種の形に成形可能であり、さらに通気性もあるので、フィルター等に好適な素材となっていた。
【００６１】
比較例 １
苛性ソーダによる加水分解を、反応温度６０℃、反応時間１時間とした以外は実施例３と同様な方法によりヒドラジン架橋されカルボン酸基を含む凝集微粒子を得た。該粒子のｐＨ緩衝性および調湿性能を評価したところ表３に示す通りであり、ＳＴＤ吸湿率が１２重量％と低く、また乾燥条件吸湿率も９重量％と低いことより、十分な調湿機能は発現されなかった。これは、親水性をもたらすカルボン酸基量が０．１２ミリ当量／ｇと低かったことが原因と考えられる。
【００６２】
【表３】

【００６３】
比較例 ２
ヒドラジンによる架橋反応を、６０℃で０．５時間で行った以外は実施例３と同様な方法によりヒドラジン架橋されカルボン酸基を含む凝集微粒子を得た。該粒子のｐＨ緩衝性および調湿性能を評価したところ表３に示す通りであり、ＳＴＤ吸湿率が１６０重量％と非常に高いものの粒子はゲル状で、粘着性があり扱いにくいものであった。また２０℃、８０％ＲＨでの吸湿率は、１８０重量％もあり、同じくゲル状で粘着性のあるものであり、凝集のため粒子粉末として取り扱えるものではなかった。また、同試料の２０℃、４０％ＲＨへ１時間おいた後の吸湿率も１７５重量％で、２０℃、８０％ＲＨの状態と殆ど変化が無く取り扱いの非常に難しいものであり、化粧料あるいはシートへの添加剤として用いることができない状態のものであった。また、吸湿機能はあるものの、放湿機能は殆ど認められなかったことより、調湿機能の点からは機能的に不十分なものであった。このように、吸湿率に変化が認められなかった原因としては、ヒドロゲル（高吸水性高分子）状態となり、表面（粒子同士が固まりとなり表面積が極端に小さなものとなっていた）は乾燥が起こったものの、中心部はゲルで保護され、乾燥が起こらなかったものと推定される。このような現象が起こった理由としては、ヒドラジンでの架橋が非常に弱かったため、ヒドロゲルに近い構造となったためと考えられる。
【００６４】
比較例 ３
苛性ソーダによる加水分解を実施し、その後の硝酸処理および硝酸カルシウム処理を施さないこと以外は実施例３と同様な方法により、カルボキシル基のすべてがナトリウム型の凝集体微粒子を得た。該微粒子のｐＨ緩衝性および調湿性能は表３に示す通りであり、調湿特性は良好であった。また、酸側での緩衝作用は優れていたが、アルカリ側の緩衝作用はまったく認められなかった。
【００６５】
比較例 ４
苛性ソーダによる加水分解を実施し、その後の硝酸処理のみ行い、硝酸カルシウム処理を施さなかった以外は実施例３と同様な方法により、カルボキシル基のすべてが水素イオン型の凝集体微粒子を得た。該微粒子のｐＨ緩衝性および調湿性能は表３に示す通りであり、調湿特性は良好であった。しかし比較例３とは逆に、アルカリ側の緩衝作用は優れていたものの、酸側での緩衝作用はまったく認められなかった。
【００６６】
以下に化粧料についての実施例および比較例を記載するが、得られた化粧料については、その使用感を次のように評価した。（ｉ）しっとり感、（ｉｉ）すべすべ感、（ｉｉｉ）滑らかさ、（ｉｖ）べとつきのなさ、（ｖ）平滑化効果について、専門パネラー２０人が顔面へ適用した場合の良否の判定に基づき、次の評価基準によリ４段階（◎、○、△、×）に評価した。さらに、（ｖｉ）すべすべ感持続性、（ｖｉｉ）滑らかさ持続性についても同様に専門パネラーによる判定に基づき、次の基準にしたがって４段階に評価した。そしてこれらの結果を表４および５にまとめた。
【００６７】
使用感評価基準
◎：１５〜２０人が使用感良好と判定
○：１０〜１４人が使用感良好と判定
△：５〜９人が使用感良好と判定
×：４人以下が使用感良好と判定
持続性評価基準
◎：１５〜２０人が使用感の持続性有りと判定
○：１０〜１４人が使用感の持続性有りと判定
△：５〜９人が使用感の持続性有りと判定
×：４人以下が使用感の持続性有りと判定
【００６８】
実施例８
表４に示す配合により、ｐＨ緩衝・調湿性重合体微粒子を除く原料を温度６０℃から８５℃に調整した反応槽で３０分間加熱撹拌した後に室温まで冷却した。次にニーダーで予め撹拌したｐＨ緩衝・調湿性重合体微粒子に、前記の冷却した原料を加えて均一になるまで混合撹拌を行いペースト状化粧料を作成した。なお、実施例８および９に用いたｐＨ緩衝・調湿性重合体微粒子は、実施例３で得られた凝集体微粒子をビーズミルにより粉砕し、平均粒子径１０μｍとしたものを用いた。この結果得られた化粧料は、しっとり感、滑らかさなどに優れ、また持続性も良好な優れた化粧料であった。
【００６９】
【表４】

【００７０】
比較例５
同じく表４に示す配合のとおり、実施例３で得られたｐＨ緩衝・調湿性重合体微粒子のかわりに平均粒子径の同様な二酸化珪素微粒子を用い、実施例８と同様な方法によりペースト状化粧料を作成した。滑らかさは良好なものの、しっとり感、すべすべ感が悪く、持続性も勿論ないものとなっていた。これは、添加した無機粒子が調湿機能を持っていないことによるものと考えられる。
【００７１】
比較例６
同じく表４に示す配合のとおり、実施例３で得られたｐＨ緩衝・調湿性重合体微粒子のかわりに比較例１で得られた凝集体微粒子を、ビーズミルにより粉砕し、平均粒子径１０μｍとしたものを用い、実施例８と同様な方法によりペースト状化粧料を作成した。該化粧料は、表４に示すとおり、べとつきのなさは良かったものの、しっとり感、滑らかさがわるく、持続性にも問題があった。この結果は、用いた比較例１の微粒子の調湿性が低いことに起因しているものと考えられる。
【００７２】
実施例９
表５に示す配合のうち、グアーゴムおよび実施例３で得られたｐＨ緩衝・調湿性重合体微粒子を除く原料を使用し、水中油型エマルジョンを調整した。次に、グアーゴムおよび該微粒子を添加し、手で混合して、皮膚に適用することができる滑らかなクリームを作成した。該クリームは、表５に示す通り、しっとり感、滑らかさ、平滑効果に特に優れ、また持続性も優れた、バランスのとれた優れた化粧料であった。
【００７３】
【表５】

【００７４】
比較例７および比較例８
同じく表５に示す配合のとおり、ｐＨ緩衝・調湿性重合体微粒子を用いることなく、実施例と同様な方法により比較例７としてのペースト状化粧料を作成した。また、比較例７にリン酸１水素２ナトリウムを加え液ｐＨを４．４に調整することにより比較例８のクリームを作成した。得られたクリームは、表５に示す通り、比較例７ではｐＨが６．７と弱酸性域ではなく、中性域となっている。この結果、いずれの項目においても良い結果は得られていない。また、比較例８では、ｐＨは４．４で弱酸性域となり比較例７よりも評価結果は良い傾向にあるが、いずれの評価項目も実用レベルにはなく、好ましい化粧料は得られていない。特に、リン酸１水素２ナトリウムというｐＨ緩衝剤を添加しているものの、その緩衝作用は初期だけのものとなっており、持続性はきわめて悪いという結果となっている。
【００７５】
比較例９および比較例１０
同じく表５に示す配合のとおり、実施例３で得られたｐＨ緩衝・調湿性重合体微粒子のかわりに、比較例９では比較例３で得られた微粒子を、比較例１０では比較例４で得られた微粒子をそれぞれ用い、クリームを作成した。なお、それぞれの凝集体微粒子は、ビーズミルにより粉砕し、平均粒子径１０μｍとしたものを用いた。比較例９のクリームは調湿という点からは良いものの、ｐＨが高く、べとつき感があることおよび持続性が無いなどの問題点がある。また、比較例１０のクリームでは、ｐＨが酸側によりすぎていること、また使用感においても良い結果は得られなかった。これは、用いた微粒子のｐＨ緩衝性が無かったためにこのような結果となったと考えられる。
【００７６】
以上のとおり、比較例に比べて本発明のｐＨ緩衝・調湿性重合体微粒子を用いた化粧料は、しっとり感、すべすべ感、滑らかさ、べとつきのなさ、平滑化効果、すべすべ感持続性、滑らかさ持続性のいずれにおいても良好な結果が得られている。これらは、本発明の重合体のｐＨ緩衝機能および調湿機能により達成されており、汗等をかいた場合でもｐＨを肌の安定域に保つ効果より、これらの優れた効果が持続され、トータル的に優れた化粧料となっているものと考えられる。
【００７７】
【発明の効果】
ｐＨ緩衝性および調湿性を兼ね備えた重合体並びに該重合体を工業的有利に製造する手段を提供し得た点が、本発明の特筆すべき効果である。また、本発明のｐＨ緩衝・調湿性重合体は、各種形状を取り得るものであり、例えば粉末状やビーズ状等の形状で添加剤として利用したり、これらを含有した紙、不織布または発泡シート状で利用することができる。また、これを化粧料に含有させることにより、トータル的に優れた化粧料とすることができる。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a polymer having pH buffering and humidity control, a method for producing the same, and a sheet-like product or cosmetic containing the polymer. More specifically, it has a humidity control function that balances moisture absorption, moisture retention and moisture release, and the polymer has a pH buffering action, and the pH range obtained by this buffering action is between 4 and 10. The present invention relates to a pH buffer / humidity-adjusting polymer and a method for producing the same, and also relates to a sheet such as paper, nonwoven fabric, and foamed sheet containing the polymer, or a cosmetic.
[0002]
[Prior art]
Under normal conditions, human skin is kept weakly acidic by secreted lactic acid, etc., but the pH of the skin exceeds the normal range due to acid rain accompanying recent environmental destruction and the alkalinization of clothes by washing. This is going to leave you healthy skin. In order to keep the pH of the skin weakly acidic, it is desirable that the acid or alkali from the outside is neutralized by clothes, and the material itself that contacts the skin is weakly acidic. As a method for responding to such a request, a protein having a weakly acidic isoelectric point attached to a fiber product by post-processing, or a fiber having a pH buffering action (JP-A-7-216730), etc. Has been proposed. However, these methods do not directly affect the skin, but are indirect methods, so the effect is not sufficient, or there is a drawback that they are effective only when wearing such clothes. .
[0003]
Furthermore, the above-described fibrous material has the following problems. 1. The first major problem is that since it is fibrous, it is difficult to disperse uniformly, for example, when it is added to a resin, cream, etc., and it can be used as an additive. I can't. 2. It is necessary to maintain the physical properties of the fiber so that it can withstand post-processing and be used as a product, so that the ability to develop pH buffering and humidity control functions may be sacrificed. For example, in the case where the fiber polymer skeleton itself is chemically modified to give pH buffering / humidity control, it is necessary to maintain a certain level or more of the fiber physical properties. In order to maintain the physical properties of the fiber, it is used for the purpose, and as a result, the pH buffering / humidifying function expression ability decreases, or the protein having the pH buffering / humidifying function is kneaded into the fiber. There is a limit to the amount of the protein that can be kneaded into the fiber, and there is a problem that the pH buffering / humidity control function cannot be fully expressed. 3. In general, fibers obtained industrially have a fiber diameter of about 10 μm or more. Therefore, the surface area per unit weight is small, and when the pH buffering / humidity control function is to be expressed, the surface area of function expression is small. There is a problem that sufficient functions are difficult to be expressed.
[0004]
For example, in the case of Japanese Patent Laid-Open No. 7-216730, since it is necessary to maintain properties such as physical properties and colors required for the fiber, a considerable amount of nitrile groups in the acrylic fiber is used for crosslinking. In this case, the nitrile group subtracted by the nitrile used for crosslinking in the acrylic fiber was chemically modified as the polar group (carboxyl group in the case of the patent) that mainly exhibits pH buffering and humidity control functions. As a result, the amount of carboxyl groups is limited to a low level, and the required function may not be sufficiently satisfied. In addition, in this patent, an amide group that is not directly related to the pH buffering / humidity control function is described as an essential component because of the reaction conditions or the physical properties of the fiber, and the function obtained per unit weight is inefficient. ing. For these reasons, it is disadvantageous in terms of cost.
[0005]
On the other hand, when looking at humidity control, the stratum corneum, which is the outermost layer of the skin, is likely to dry under weather conditions such as low temperatures and low humidity in winter, and the skin becomes rough or rough. In addition, excessive use of detergents and solvents can cause skin irritation and roughness. Such skin roughness and roughness is caused by the loss of moisture-absorbing water-soluble component called NMF (natural moisturizing factor) in the stratum corneum, reducing the water in the stratum corneum and softening the stratum corneum. It is thought to be caused by the loss of sex.
[0006]
Therefore, conventionally, in cosmetics intended to soften the skin, various moisturizing ingredients have been blended in order to impart a large amount of moisture to the stratum corneum and to retain the imparted moisture for a long time. ing. In particular, since NMF components contain organic acids (carboxylic acids), amino acids, urea, etc., various organic acids, amino acids, or urea are blended into cosmetics, and the lost NMF components are replenished to the skin. Things have been done.
[0007]
For example, a compound using an organic acid as one of the NMF components has been proposed that utilizes the stratum corneum softening action of α-oxyacid (Japanese Patent Laid-Open No. 55-19291). However, the resulting flexibility effect is temporary and does not last. Further, the pH at which the α-oxyacid exerts the stratum corneum softening action has a disadvantage that it is a low region (pH 2 to 4) that inhibits normal skin physiology.
[0008]
On the other hand, an example of adding an alkali such as sodium hydroxide, potassium hydroxide or triethanolamine to a solution of α-oxyacid in order to use α-oxyacid in a neutral pH region has been reported. However, when a large amount of alkali is blended, the stability of the solution is lowered, and it becomes difficult to maintain the cosmetics in stable quality. In addition, since the pH which is originally preferred for the skin is weakly acidic at about 4 to 6, the use of a large amount of alkali is harmful to the skin. Furthermore, it has been reported that an allergic reaction is caused by prolonged use of amines.
[0009]
In addition, it has been proposed that succinic acid or a salt thereof as an organic acid of the NMF component is blended with cosmetics together with urea and amino acids (Japanese Patent Laid-Open No. 5-163129). Furthermore, as one of the NMF components, it is reported that a protein degradation product such as Yokuinin and certain peptides have a moisturizing effect and a softening effect as those using amino acids or derivatives thereof (Japanese Patent Laid-Open No. 2005-259151). Sho 62-99315, JP-A-2-178207).
[0010]
In addition to the above-mentioned NMF-related components, water-soluble polyhydric alcohols, particularly propylene glycol and polyethylene glycol having a molecular weight of about 200 to 400 are widely used as a moisturizer or softener. Further, since betaine has an effect of increasing the turnover speed of the stratum corneum and preventing rough skin, it has been proposed to blend this into cosmetics (Japanese Patent Laid-Open No. 1-275511).
[0011]
However, organic acids such as α-oxy as described above, and conventional NMF-related components such as amino acids or derivatives thereof have a sticky feeling, and therefore a satisfactory feeling of use cannot be obtained from cosmetics containing these. There was a problem. In addition, in order to obtain a sufficient moisturizing effect, water-soluble polyhydric alcohols such as propylene glycol and polyethylene glycol also need to be blended in a large amount in cosmetics, in which case there is a problem that a sticky feeling occurs. . Furthermore, there has been concern about a large amount of use from the viewpoint of safety (allergy). On the other hand, for betaine, cosmetics containing the same have an excellent moisturizing effect, but it has been desired to improve the feeling of use such as moist feeling, smooth feeling or smoothness.
[0012]
As another application, a filter having a humidity control function such as moisture absorption, moisture retention and moisture release is required. In view of this, a fiber-like one as described above has been proposed. However, in the case of a fibrous form, the above-mentioned problems occur to maintain the fiber form, and the function is insufficient or the function is blocked by a binder or the like when molding into a filter because the unit surface area is small. There is a problem that the function cannot be fully exhibited.
[0013]
[Problems to be solved by the invention]
The present invention is intended to solve the above-mentioned problems of the prior art, and has a humidity control function that balances moisture absorption, moisture retention and moisture release, and pH buffer / humidity control with a moderate pH buffering effect. Polymer and method for producing the polymer, and sheet containing the polymer, or a makeup that improves both the moisturizing effect and the feeling of moistness, smoothness, or smoothness, and also enhances the sustainability thereof The purpose is to provide a fee.
[0014]
[Means for Solving the Problems]
The present inventor has continually studied about a pH buffering / humidifying polymer. As a result, in a polymer having an ion-exchangeable polar group and a crosslinked structure, the polymer has specific moisture absorption characteristics and moisture retention / moisture release characteristics, and the pH range obtained by the buffering action of the polymer is 4-10. It has been found that this problem can be achieved by the intervening pH buffer / humidity-controlling polymer, and the present invention has been completed. That is, in the present invention, the polymer having an ion-exchange polar group and a crosslinked structure has a moisture absorption rate of 15% by weight or more and 100% by weight or less at 20 ° C. and 65% RH as moisture absorption characteristics. Moisture absorption and moisturization with moisture absorption of 15% to 80% by weight after leaving the polymer saturated at 20 ° C. and 80% RH for 1 hour as a moisture release characteristic at 20 ° C. and 40% RH A pH buffer / humidity-adjusting polymer characterized by having a humidity-controlling function with balanced moisture release and having a pH range of 4 to 10 obtained by the buffering action of the polymer A method, and a sheet or cosmetic containing the polymer. The present invention will be described in detail below.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
First, the polymer of the present invention has a moisture absorption rate of 20% to 100% by weight at 20 ° C. and 65% RH as moisture absorption properties, and 20 ° C. and 80% RH as moisture retention / moisture release properties. Moisture conditioning with a balance of moisture absorption, moisture retention and moisture release when the polymer that has been saturated and moisture-absorbed under conditions of 20 ° C. and 40% RH after standing for 1 hour has a moisture absorption rate of 15 wt% to 80 wt% The pH range which has a function and is obtained by the buffer action of this polymer needs to be between 4-10.
[0016]
Here, the moisture absorption rate defined in the present invention refers to the moisture absorption rate obtained by the following method. That is, about 5.0 g of a sample is dried with a hot air dryer at 105 ° C. for 16 hours and weighed (W1) g, and then the sample is subjected to a specific temperature and humidity condition (for example, a temperature of 20 ° C. and a relative humidity of 65% RH). ) Is placed in a thermo-hygrostat adjusted for 24 hours, and the weight of the moisture-absorbed sample is measured (W2) g. From the above results, the following formula is calculated.
Moisture absorption rate (% by weight) = {(W2−W1) / W1} × 100
Further, the moisture retention / moisture release characteristics are defined as the moisture absorption rate after leaving the polymer saturated and absorbed at 20 ° C. and 80% RH for 1 hour at 20 ° C. and 40% RH. .
[0017]
The pH range obtained by the buffering action is that after 5.0 g of a sample dried at 105 ° C. for 16 hours with a hot air dryer is added to 100 g of an aqueous solution adjusted to pH = 2 with hydrochloric acid and stirred at room temperature for 1 hour. The pH is adjusted to the acidic side, and the sample is added to 100 g of an aqueous solution adjusted to pH = 12 with sodium hydroxide. After stirring for 1 hour at room temperature, the pH is set to the alkaline side. The pH on the side is expressed as a range.
[0018]
As a moisture absorption characteristic, when the moisture absorption rate under 20 ° C. and 65% RH is less than 15% by weight, the moisture absorption rate is too low to obtain a sufficient effect. In addition, when the moisture absorption rate exceeds 100% by weight under the same conditions, the swelling of the particles becomes too large, making it difficult to use as an additive, and the passage of gas is blocked by the swelling, resulting in a decrease in the moisture absorption rate. The problem comes out. In addition, problems such as stickiness appear, which is not preferable. In addition, as a moisture retention / moisture release property, when a moisture absorption rate after leaving a polymer that has been saturated and absorbed at 20 ° C. and 80% RH for 1 hour at 20 ° C. and 40% RH is less than 15% by weight, moisture is released. Since the speed is too high, sufficient moisture retention cannot be maintained. Further, when the moisture absorption rate after standing under the same condition exceeds 80% by weight, the same problem as the problem when the moisture absorption characteristic exceeds 100% by weight occurs. In particular, this problem becomes remarkable when moisture is absorbed, that is, under the conditions of 20 ° C. and 80% RH.
[0019]
When the pH range obtained by the buffering action is less than 4, a sufficient effect cannot be obtained by adding a small amount, that is, it cannot be made weakly acidic. Alternatively, when the region exceeds 10, a sufficient effect cannot be obtained in the same manner, and there is a problem that the pH cannot be stabilized efficiently in the vicinity of neutrality.
[0020]
The ion-exchangeable polar group referred to in the present invention is not particularly limited as long as it is a polar group capable of ion-exchange of an anion or cation ion, for example, a primary amino group, a secondary amino group, a tertiary amino group. A quaternary amino group, a phosphoric acid group, a phosphoric acid ester group, a hydroxyl group, a mercapto group, a carboxyl group, a sulfonic acid group, a sulfonyl group, a sulfuric acid ester group and the like can be mentioned. Among them, when a sulfonic acid group, a carboxyl group, or a phosphoric acid group that easily forms a complex or a salt with a metal ion is used, a desired polymer having excellent pH buffering and humidity control properties can be obtained, and good results can be obtained.
[0021]
The amount of the above-mentioned polar group contained in the polymer of the present invention is not particularly limited as long as the pH buffering / humidity control required according to the actual use can be expressed, and can be appropriately selected. it can. However, it is preferable that the amount of polar groups contained in order to enhance the pH buffering / humidity control function is large. In practice, it is preferable to contain at least 0.1 meq / g or more of polar groups, and a small amount as an additive. From the fact that its function can be expressed by addition of, particularly preferable results can be obtained at 2.0 meq / g or more.
[0022]
Also, there is no particular limitation on the method for introducing the polar group into the polymer particle. The introduction of the polar group-containing monomer by using it in the polymerization step of the backbone polymer, or the formation of the backbone polymer particle after chemical and physical A method such as introduction of a polar group by modification can be used. However, since it is necessary to contain as much polar groups as possible, there is a problem that if a large amount of monomers having polar groups are added in the polymerization stage, the stability is lowered in both aqueous and non-aqueous polymerizations. . Therefore, better results can be obtained by introducing a polar group by conducting a chemical and physical reaction after polymerized into polymer particles.
[0023]
Moreover, there is no limitation in particular as a counter ion of the above-mentioned ion-exchange polar group, According to the use, it can select suitably. Specifically, among the above, the counter ions of the acidic group include not only hydrogen ions but also alkali metals Be such as Li, Na and K, alkaline earth metals such as Mg, Ca and Ba, Cu and Zn. Other metals such as Al, Mn, Ag, Fe, Co and Ni, and organic cations such as NH4 and amine can be mentioned. Examples of basic groups include hydroxyl, chlorine, fluorine, bromine and the like. Of course, two or more of the counter ions may be mixed.
[0024]
Especially, when it contains any one of Ca, Mg, Na, K, Li, and Al as hydrogen ions and metal ions, it is easy to balance acid and alkali, so that good results with excellent pH buffering properties are obtained. Obtainable. In this case, the equivalent ratio of hydrogen ions to metal ions is not particularly limited, but better results can be obtained by setting the ion ratio in the range of 1.0 to 1.5 to 4.0 to 1.0. Can be obtained. When the ratio of hydrogen ions is higher than 4.0 to 1.0, the buffering property against an alkaline substance is not sufficient, although the buffering property against an alkaline substance is large. On the other hand, when the ratio of metal ions is higher than 1.0 to 1.5, the buffering property for an alkaline substance tends to be insufficient although the buffering property for an acidic substance is large.
[0025]
As described above, the method for adjusting the equivalent ratio including hydrogen ions and metal ions can be selected as appropriate, and is not particularly limited. However, the following method is advantageous in terms of process and cost. That is, when hydrolysis with acid is performed, at least one hydroxide selected from Ca, Mg, Na, K, Li, and Al is added to adjust the pH to 5.0 to 7.0. After washing with water and drying. In the case of hydrolysis with alkali, acid treatment is performed once, and the total amount of acidic ion exchange groups such as carboxyl groups is converted to hydrogen ion type, followed by Ca, Mg, Na, K, Li, Al nitrate, hydrochloric acid In this method, one or more metal salts selected from salts, sulfates and phosphates are added, adjusted to pH 5.0 to 7.0, and then washed with water and dried.
[0026]
The polymer of the present invention is not particularly limited as long as it has an ion-exchangeable polar group and a crosslinked structure, and may be any of natural polymers, semi-synthetic polymers, and synthetic polymers. Specific polymers include, for example, polyethylene, polypropylene, vinyl chloride, ABS resin, nylon, polyester, polyvinylidene chloride, polyamide, polystyrene, polyacetal, polycarbonate, acrylic resin, fluororesin, polyurethane elastomer, polyester elastomer, melamine resin, urea. Plastic polymers such as resin, tetrafluoroethylene resin, unsaturated polyester resin, epoxy resin, urethane resin and phenol resin; nylon, polyethylene, rayon, acetate, acrylic, polyvinyl alcohol, polypropylene, cupra, triacetate, vinylidene, etc. Fiber-forming polymers: natural rubber and silicone rubber, SBR (styrene butadiene rubber), CR (chloroprene rubber), PM (ethylene propylene rubber) FPM (fluorine rubber), NBR (nitrile rubber), CSM (chlorosulfonated polyethylene rubber), BR (butadiene rubber), IR (synthetic natural rubber), IIR (butyl rubber), urethane rubber and acrylic Examples thereof include synthetic rubber polymers such as rubber.
[0027]
In particular, polymers with basic skeletons based on carbon-carbon bonds from the viewpoint of heat resistance and chemical resistance that can withstand physical and chemical changes associated with the introduction of polar groups or ion exchange of these groups. For example, a vinyl-based polymer is preferable, and a polymer to which an ion-exchangeable polar group can be easily introduced, specifically, a polystyrene-based, polyacrylonitrile-based, polyacrylic ester-based, or polymethacrylic ester-based polymer. Good results can be obtained by using.
[0028]
The crosslinking structure contained in the basic skeleton polymer is not particularly limited as long as the polymer is not physically or chemically modified in the step of introducing ion-exchange or ion-exchange polar groups. Any structure such as cross-linking by covalent bond, ionic cross-linking, interaction between polymer molecules or cross-linking by crystal structure may be used. In addition, there is no particular limitation on the method for introducing the cross-linking, and it depends on a generally used method such as cross-linking with a cross-linking agent in the polymerization step of the skeleton polymer, post-cross-linking after polymerization, or introduction of a cross-linked structure by physical energy. be able to. Among these, those introduced with a crosslinking agent by divinylbenzene or triallyl isocyanurate are preferable from the viewpoint that a crosslinked structure which is easily thermally and chemically stable can be introduced into the vinyl polymer. In addition to this, the nitrile group contained in the high nitrile polymer having a content of the vinyl monomer having a nitrile group of 50% by weight or more and hydrazine has the advantage that the form can be maintained because it can be post-crosslinked. A method using a post-crosslinking method comprising a structure obtained by reaction with a compound or formaldehyde, particularly a method using a hydrazine compound, can obtain excellent results as described below.
[0029]
The above-mentioned high nitrile polymer means a polymer having a high nitrile group content, and specifically refers to a polymer having a nitrile group-containing vinyl monomer content of 50% by weight or more. The vinyl monomer having a nitrile group that is a raw material of the high nitrile polymer is not particularly limited as long as it has a nitrile group, and specifically, acrylonitrile, methacrylonitrile, ethacrylonitrile, α-chloroacrylonitrile. , Α-fluoroacrylonitrile, vinylidene cyanide and the like. Of these, acrylonitrile is preferable because it is advantageous in terms of cost and has a large amount of nitrile groups per unit weight.
[0030]
Specifically, the amine structure introduced by treating with the nitrile group in the high nitrile polymer and the hydrazine compound is an amino group (primary-NH2, secondary-NHR, tertiary- NRR ′), imino group, hydrazino group, hydrazono group, hydrazo group, diazoamino group, ureido group, ureylene group, guanidino group, hydrazinocarbonyl group, amidino group, carbamoyl group, etc. The structure is mixed and part of it contributes to the cross-linking. The amine structure may be chain-like or cyclic (triazole ring, tetrazine ring, etc.). The content of these amine structures can be expressed as the sum of the exchange capacities (milli equivalents / g) of the above basic groups such as amino groups and imino groups.
[0031]
The treatment for introducing the amine structure is not particularly limited as long as a crosslinked structure can be obtained, and the treatment according to the intended use, that is, the reaction conditions can be appropriately selected. For example, the reaction state of the high nitrile polymer and the hydrazine compound may be a molten state that is higher than the melting point, a state in which the reactant is dissolved in an organic or inorganic solvent, or a reaction such as an organic solvent or water. The state of being dispersed in a medium can be selected as appropriate. At this time, the concentration of the high nitrile polymer and the hydrazine compound in a reaction such as dilution with a solvent or dispersion in a solvent can be appropriately selected in the reaction. Moreover, there is no limitation in particular as reaction temperature, Reaction temperature according to each above-mentioned reaction state can be set suitably. However, when the temperature is too low, the reaction rate is slow and the reaction time is too long. Therefore, preferable results are often obtained when the reaction is carried out at a temperature of 50 ° C. or higher, more preferably 80 ° C. to 150 ° C. Moreover, there is no limitation in particular also about the site | part with which a high nitrile polymer and a hydrazine type compound are made to react, According to the use and the form of a polymer, it can select suitably. Specifically, the reaction can be appropriately selected such as reacting only on the surface of the high nitrile polymer, reacting up to the entire core, or reacting by limiting a specific site. The hydrazine compounds used herein include hydrazine salts such as hydrazine hydrate, hydrazine sulfate, hydrazine hydrochloride, hydrazine nitrate, hydrazine bromate, hydrazine carbonate, and ethylenediamine, guanidine sulfate, guanidine hydrochloride, guanidine nitrate, phosphorus Hydrazine derivatives such as acid guanidine and melamine.
[0032]
Here, in the case where the polymer of the present invention is an acrylonitrile-based polymer that has been crosslinked with a hydrazine-based compound, a derivative obtained by converting 0.1% by weight or more of the residual nitrile group into a carboxyl group is as follows. Is preferable. In other words, there are advantages that the amphoteric nature of anion and cation can give a betaine-like function as described above, and ions can be more efficiently ion-exchanged into the polymer. In this case, when all of the remaining nitrile groups are finally converted to carboxyl groups, the amount of carboxyl groups as ion exchange groups is the largest, giving particularly favorable results in terms of function as described above. is there.
[0033]
In the case of a high nitrile polymer, the form thereof is not particularly limited, and an appropriate one such as a particulate shape, a resin molded body shape, or a foamed shape can be adopted. Further, the composition of the polymer is not particularly limited as long as the content of the vinyl monomer having a nitrile group is 50% by weight or more, and the vinyl monomer having a nitrile group alone or the content of the monomer is 50% by weight. % Or more, and the balance may be at least one other ethylenically unsaturated compound. Specific examples of other ethylenically unsaturated compounds mentioned here include known unsaturated compounds that can be copolymerized with the above-mentioned vinyl monomers having a nitrile group, such as vinyl chloride, vinyl bromide, vinyl fluoride, and chloride. Vinyl halides and vinylidene halides such as vinylidene; unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, itaconic acid and their salts; methyl acrylate, ethyl acrylate, butyl acrylate, octyl acrylate, Acrylic esters such as methoxyethyl acrylate, phenyl acrylate, cyclohexyl acrylate, etc .; Methacrylic esters such as methyl methacrylate, ethyl methacrylate, butyl methacrylate, octyl methacrylate, phenyl methacrylate, cyclohexyl methacrylate; methyl vinyl Tons, phenyl vinyl ketone, methyl isobutenyl ketone, methyl isopropenyl ketone, etc .; vinyl esters such as vinyl formate, vinyl acetate, vinyl propionate, vinyl butyrate, vinyl benzoate; methyl vinyl ether, ethyl vinyl ether Vinyl ethers such as acrylamide, and alkyl-substituted products thereof; unsaturated sulfonic acids such as vinyl sulfonic acid, allyl sulfonic acid, methallyl sulfonic acid, and styrene sulfonic acid; and salts thereof; styrene such as styrene, methyl styrene, and chlorostyrene; Alkyl or halogen substituted products thereof; allyl alcohol and esters or ethers thereof; basic vinyl compounds such as vinylpyridine, vinylimidazole, dimethylaminoethyl methacrylate; acrolein, Unsaturated aldehydes such as crylolein; crosslinkable vinyl compounds such as glycidyl methacrylate, N-methylol acrylamide, hydroxyethyl methacrylate, triallyl isocyanurate, divinylbenzene, ethylene glycol di (meth) acrylate, and methylenebisacrylamide .
[0034]
There is no particular limitation on the method of treating a high nitrile polymer with a hydrazine compound and introducing an amine structure into the polymer and forming a post-crosslink, but the polymer is in an aqueous solution having a hydrazine compound concentration of 1 to 80% by weight. Means for treating at a temperature of 50 to 140 ° C. for 1 to 15 hours give industrially favorable results.
[0035]
In the hydrazine treatment, the reaction of the nitrile group of the raw high nitrile polymer with the amine of the hydrazine compound results in the generation of a crosslinked structure having the above amine structure and the introduction of the same amine structure derived from the hydrazine compound. Seem. Moreover, it seems that 1 part of carboxyl groups are also produced by hydrolysis of nitrile groups.
[0036]
In the case of treatment with this hydrazine compound, if the hydrazine compound ion-bonded with the carboxyl group generated by hydrolysis of the nitrile group is liberated and causes a problem, an acid treatment may be performed to remove it. . As the method, a method of immersing the hydrazine-based compound-treated polymer described above in various acidic aqueous solutions such as hydrochloric acid, acetic acid, nitric acid, sulfuric acid, etc. and then drying is suitably used. However, from the viewpoint of imparting pH buffering properties, if the acid treatment is excessively performed, the pH buffer performance is lowered. Therefore, in order to restore the ability reduced by the acid treatment, the pH is adjusted and ionized amine is recovered. It is desirable to make part of the structure neutral. In this case, there may be mentioned means for adjusting the pH to a desired level while the polymer is immersed in a basic aqueous solution such as alkali metal hydroxide and ammonia, and then drying.
[0037]
The form of the pH buffer / humidity-controlling polymer in the present invention is not particularly limited, and can be appropriately selected according to the application for practical use. Specifically, it is a three-dimensional block, that is, a plastic, a resin molded body, a plastic foam, a planar film, a coating film, paper, a nonwoven fabric, a sheet-like plastic foam, or a particulate powder. In particular, in the case of particulate powder, since it can be used as an additive in each of the above-mentioned forms, its applicable range is wide and useful. Further, since the particulate powder has a larger surface area per unit weight than other forms, the pH buffering / humidifying speed is increased. In addition, even if the exchange capacity of ion-exchangeable polar groups that contribute to pH buffering / humidity control is the same, since the polar groups are often located near the surface, the exchange capacity can be used effectively. There is an advantage that you can.
[0038]
When the pH buffering / humidifying polymer is a particulate powder, its shape is not particularly limited, and is spherical, needle-like, spindle-like, rod-like, cylindrical, polyhedral, multi-needle, flat, Any shape such as a scaly shape, an indefinite shape, or an aggregated state of each shape body can be used. Further, the size of these particles can be appropriately selected according to the use, and is not particularly limited. However, when the average particle size is in the form of particles of 1000 μm or less, more preferably in the case of fine particles of 100 μm or less. In this case, the surface area is increased, the pH buffering / humidity control performance is improved, and good results can be obtained. Also, good results can be obtained when the polymer is in the form of aggregated particles, particularly aggregates of particles having an average particle size of primary particles of 5 μm or less, and the average particle size of the aggregates of 100 μm or less. In this case, an appropriate cavity is formed in the gap between the primary particles, and the surface area per unit weight is increased, so that excellent results can be obtained.
[0039]
Among the usage forms of the polymer obtained by the present invention, in particular, when used as paper, non-woven fabric or foamed sheet, the contact area with gas is large, and the form-retaining property is excellent. Useful as. The method for constructing this paper, nonwoven fabric or foamed sheet is not particularly limited as long as the pH buffering / humidifying polymer of the present invention is used. Specifically, the form is composed of the fibrous polymer. Any method may be used, or a method in which the particulate polymer is supported. However, better results can be obtained in the case of supporting particulate pH buffer / humidity control polymer from the viewpoints of low cost, large surface area per unit weight, and high pH buffer / humidity control efficiency. Can do.
[0040]
There are no particular restrictions on the loading method, such as mixing, impregnation or inclusion in the matrix constituting the material, and various methods can be employed. Further, the pH buffer / humidity-controlling polymer particles may be present inside the matrix or may be present on the surface of the matrix. For example, a method of mixing the polymer particles in the production process of paper, nonwoven fabric, foamed sheet, etc. Alternatively, any method such as a method of impregnating them with a slurry of the polymer particles can be employed.
[0041]
As a specific example, in the case of producing paper by a papermaking technique using pH buffer / humidity-controlling polymer particles as a filler, the polymer is added to a slurry of a papermaking material such as pulp or synthetic fiber dispersed in a large amount of water. After adding particles and other additives, they can be mixed well and produced using a normal paper machine. At this time, if necessary, a fixing agent can be added in order to suppress the loss of the filler. Examples of the fixing agent include polyethyleneimine modified products, polyacrylamide modified products, sodium alginate, gum arabic, and positive tempun. , Aluminum sulfate, potash and vane. The amount of the fixing agent used can be appropriately selected depending on the type of the fixing agent and the amount of the polymer particles used. Furthermore, sizing agents, dyes, paper strength enhancing agents and the like generally used in the paper making process can be used as appropriate. The surfactant can be appropriately selected from anionic, cationic or nonionic surfactants in consideration of other additives. The pH buffer / humidity-controlling polymer particles used in these papermaking are not particularly limited, but preferable results are obtained when powders having a particle diameter of 1 to 100 μm are used. If the particle size is smaller than 1 μm, it may drop together with water from the paper machine's net during paper making, while if it exceeds 100 μm, it may be too large and difficult to disperse uniformly. .
[0042]
Moreover, when forming as a nonwoven fabric, there is no limitation in particular and it can apply to the nonwoven fabric produced with various manufacturing methods. Specifically, in the dry method, an adhesive type immersion method, a printing method, a spray method, a powder method, an adhesive fiber method (thermal bond method), a mechanically bonded felt method, a stitch method, a needle punch method, a water flow Entanglement type spunlace method, spinning type spunbond method, mesh method, melt blow method, film method, wet method, hydroentangled type spunlace method, spinning type spunbond method, flash spinning method, papermaking mold Examples thereof include a heat-bonding fiber method, a hot-pressing method, and an adhesive method. There is no particular limitation on the method of supporting the pH buffer / humidity-controlling polymer. For example, it is supported by various methods such as sandwiching between these non-woven fabrics, adhering to the fiber material constituting the non-woven fabric, and applying to the non-woven fabric surface be able to. In addition, the basis weight of these nonwoven fabrics is not particularly limited, but those having a basis weight of 20 to 300 g / m2 often give good results. If the basis weight is less than 20 g / m2, the strength is low, causing blurring. easy. Moreover, when it exceeds 300 g / m <2>, there exists a tendency for the permeability of a gas-liquid to become low, and it may be unpreferable. Particularly preferred non-woven fabrics are spunbond non-woven fabrics formed using a composite fiber composed of a sheath component made of polyethylene and a core component made of polypropylene or polyester, and a polyester fiber web layer on the surface and a polypropylene web layer on the back surface. A non-woven fabric having a two-layer structure can be used, and these non-woven fabrics can be obtained from preferable raw materials because they can be easily processed due to the low melting point polyolefin component. When a plastic foam is used as a matrix, the polymer particles are mixed with a plastic foam, for example, foamed polyurethane, or impregnated with a slurry of pH buffer / humidity-adjusting polymer particles, by a usual method. The intended polymer-containing plastic foam can be obtained.
[0043]
Since the pH buffer / humidity-controlling polymer in the present invention has an excellent pH buffering property and humidity-controlling effect, the use of the polymer as a raw material for cosmetics provides moisturizing effect, moist feeling, and smoothness. Both a feeling of use or a feeling of smoothness of use can be satisfied, and a cosmetic excellent in sustainability of the effect can be obtained. The cosmetic in the present invention is not particularly limited as long as it contains the above-described pH buffering / humidifying polymer of the present invention. Here, the content ratio of the polymer in the cosmetic is not particularly limited, but is usually 0.01 to 40% by weight. If it is less than 0.01% by weight, it is difficult to obtain a sufficient pH buffering / humidifying effect, and even if it exceeds 40% by weight, it is often impossible to obtain an effect according to the amount.
[0044]
In addition, the cosmetics may further contain other moisturizers, thickeners, preservatives, surfactants, oils, antioxidants, chelating agents, ultraviolet absorbers, powders, pigments, medicinal ingredients, fragrances, Etal, purified water and the like can be contained within a range not impeding the effects of the present invention. In addition, the cosmetic is not particularly limited with respect to the dosage form, and can be applied to lotions, emulsions, creams, packs, jewellery, foundations and the like. Moreover, it can be set as various phase aspects, such as a uniform solution system, an emulsion system, and a two-layer system. In this case, a manufacturing method can be based on a conventional method.
[0045]
[Action]
The reason why the pH buffer / humidity-adjusting polymer according to the present invention and the excellent pH buffering / humidity-adjusting performance are imparted by the production method has not yet been fully elucidated, but is generally considered as follows. That is, the polymer according to the present invention has a large amount of ion-exchange polar groups, and these polar groups are very hydrophilic and easily absorb moisture. In addition, unlike the general free water, the absorbed water is hard to be separated because it is firmly fixed to the polar group as bound water. As a result, it is considered that moisture retention and gentle moisture release are possible. In addition, the pH buffering property is considered to be a result of the above-described large amount of ion-exchangeable polar groups balancing acidity and basicity.
[0046]
【Example】
The present invention will be specifically described below with reference to examples. Percentages and parts in the examples are on a weight basis unless otherwise indicated. First, each evaluation method and definitions of terms will be explained.
[0047]
The moisture absorption rate of the polymer was measured by the method described above. The description in the table in the examples is described in the item of STD moisture absorption rate (standard condition moisture absorption rate), where the moisture absorption rate at 20 ° C. and 65% RH represents the moisture absorption characteristic. That is, the larger this value, the better the moisture absorption characteristics. In addition, the moisture retention / moisture release characteristics are described in terms of moisture absorption rate under dry conditions, and the moisture absorption rate at 20 ° C. and 80% RH and a sample adjusted to the conditions at 20 ° C. and 40% RH for 1 hour. The moisture absorption rate after standing was described. In this case, it can be determined that the higher moisture absorption rate of the latter and the greater the difference in moisture absorption rate between the former and the latter, the better the moisture retention and moisture release characteristics.
[0048]
The pH buffering ability was also measured by the method described above. The description in the table in the examples describes the pH values obtained on the low pH side (acid side) and high pH side (alkaline side) as the acid side pH buffer value and the alkali side pH buffer value, respectively. did. From the viewpoint of pH buffering properties, the closer these values are to 7, the better the buffering effect.
[0049]
The average particle diameter of the particulate matter is expressed on a volume basis using a laser diffraction particle size distribution measuring device “SALD2000” manufactured by Shimadzu Corporation, and the average particle diameter is the median diameter. .
[0050]
The amount of ion-exchangeable polar groups obtained by the reaction was determined by acid-base titration, and the amount of polar groups was determined from the titration curve.
[0051]
Example 1
300 parts of a water-soluble polymer of methacrylic acid / p-sodium styrenesulfonate = 70/30 and 30 parts of sodium sulfate were dissolved in 6595 parts of water and charged into a polymerization tank equipped with a vertical stirrer. Next, 15 parts of 2,2′-azobis- (2,4-dimethylvaleronitrile) was dissolved in 2700 parts of methyl acrylate and 300 parts of divinylbenzene and charged into the polymerization tank. Polymerization was performed for a time to obtain a methyl acrylate / divinylbenzene copolymer having a polymerization rate of 87% and an average particle size of 64 μm. 100 parts of the polymer was dispersed in 900 parts of water, 100 parts of caustic soda was added thereto, reacted at 90 ° C. for 2 hours, and the methyl ester part of methyl acrylate was hydrolyzed to obtain 4. A crosslinked polymer having 5 meq / g was obtained. The obtained polymer was dispersed in water, adjusted to pH 6.5 with nitric acid, calcium nitrate was added, and a metal salt treatment was performed at 60 ° C. for 2 hours. Then, washing, dehydration, and drying were performed to obtain pH buffered / humidifying polymer fine particles. The characteristics of the fine particles are summarized in Table 1. As can be seen from these results, it was confirmed that the polymer fine particles had excellent pH buffering properties and humidity control properties.
[0052]
[Table 1]

[0053]
Example 2
300 parts of a water-soluble polymer of methacrylic acid / p-sodium styrenesulfonate = 70/30 and 30 parts of sodium sulfate were dissolved in 6595 parts of water and charged into a polymerization tank equipped with a vertical stirrer. Next, 15 parts of 2,2′-azobis (2,4-dimethylvaleronitrile) was dissolved in 2700 parts of acrylonitrile (AN) and 300 parts of methyl acrylate and charged into the polymerization tank, and the mixture was charged at 60 ° C. under stirring conditions of 400 rpm. For 2 hours to obtain a high nitrile polymer having a polymerization rate of 87% and an average particle size of 52 μm. 100 parts of the polymer was mixed with 50 parts by weight of hydrazine 60 parts by weight and 850 parts of water, and subjected to hydrazine treatment at 90 ° C. for 3 hours to introduce crosslinking, and further 100 parts of caustic soda was added. By carrying out the reaction at 2 ° C. for 2 hours, all the remaining nitrile groups were hydrolyzed to introduce carboxylic acid groups (sodium type at the end of the hydrolysis reaction). The obtained polymer is dispersed in water, adjusted to pH 6.5 with nitric acid, added with calcium nitrate, treated with a metal salt at 60 ° C. for 2 hours, washed, dehydrated and dried to provide pH buffering and humidity control. Polymer fine particles were obtained. The characteristics of the fine particles are summarized in Table 1. As can be seen from these results, it was confirmed that the polymer fine particles had excellent pH buffering properties and humidity control properties.
[0054]
Example 3
After charging 450 parts of acrylonitrile, 50 parts of methyl acrylate and 1181 parts of water into a 2 liter autoclave, and further adding 0.5% by weight of di-tert-butyl peroxide as a polymerization initiator to the total amount of monomers. , Sealed, and then polymerized under stirring at a temperature of 120 ° C. for 30 minutes. After completion of the reaction, the mixture was cooled to about 90 ° C. while continuing stirring to obtain an aggregate fine particle dispersion having an average particle size of 38 μm. When the primary particles of the aggregate fine particles were observed with an electron microscope, the average particle size was 0.3 μm. The obtained aggregated fine particles were subjected to hydrazine crosslinking and hydrolysis in the same manner as in Example 2, and further subjected to pH adjustment treatment to obtain pH buffered / humidity-adjusting polymer fine particles. The characteristics of the fine particles are summarized in Table 1. As can be seen from these results, it was confirmed that the polymer fine particles had excellent pH buffering properties and humidity control properties. Moreover, compared with Example 2, pH buffer property and humidity control property were excellent, and the speed | rate which pH buffer acts, and the speed | rate until it reached equilibrium of humidity control property were excellent compared with Example 2. This is because Example 3 is in the form of agglomerates of fine particles, the surface area was increased, and the space between the primary particles worked effectively for diffusion of moisture and the like, and these gave good results. Conceivable.
[0055]
Example 4
By using a strongly acidic ion exchange resin “DIAION SK 1B” manufactured by Mitsubishi Chemical Corporation having styrene / divinylbenzene as a polymer skeleton and a sulfonic acid group as a polar group, the pH is adjusted by the same method as in Example 1. Buffered / humidified polymer fine particles were obtained. The characteristics of the fine particles are summarized in Table 1. As can be seen from these results, it was confirmed that the polymer fine particles had pH buffering properties and humidity control properties, but their effects were slightly inferior to those of Examples 1 to 3. This is considered to be due to the large particle size and the low ion exchange capacity.
[0056]
Example 5
Softwood pulp and hardwood pulp were mixed at a weight ratio of 7: 3 and beaten so that the Canadian standard freeness was 360 cc. This pulp is dispersed in water to prepare a pulp slurry having a concentration of 0.3% by weight, and the pH buffer / humidity-adjusting polymer fine particles obtained in Example 3 are added at a concentration of 0.7% by weight, to JIS-P8209. Paper was made according to the standards. The resulting product paper had a content of the fine particles of 70% by weight and a basis weight of 85 g / m 2. Table 2 shows the results of evaluating the pH buffering and humidity control properties of the obtained paper. As can be seen from the table, good pH buffering and humidity control were also observed for the obtained paper, and it was confirmed that the ability of the raw material fine particles was well expressed.
[0057]
[Table 2]

[0058]
Example 6
A hot-melt nonwoven fabric having a coarse mesh size of 20 g / m 2 is placed on the upper surface of a net-like nonwoven fabric having a weight of 80 g / m 2 made of 5-denier polypropylene fiber, and the pH buffering / humidity adjusting weight obtained in Example 3 is placed on the upper surface. Sprinkling the coalesced fine particles in an amount of 60 g / m 2, heating and bonding them, yielded a nonwoven fabric containing pH buffering / humidifying polymer fine particles. The nonwoven fabric had high air permeability and well retained the pH buffer / humidity-controlling polymer fine particle layer. The pH buffering and humidity control properties were also good as shown in Table 2, and it was confirmed that the ability of the raw material fine particles was well expressed as in Example 5.
[0059]
Example 7
Similarly, the pH buffer / humidity-controlling polymer fine particles obtained in Example 3 were mixed with a urethane resin according to the following formulation, and the mixture was cast on a release paper and dry-foamed to obtain a foamed urethane sheet containing the fine particles. Produced.
100 parts of urethane resin (UF-3A, manufactured by Seiko Kasei)
10 parts of filler (FAD30, manufactured by Seiko Kasei)
1 part of foaming agent (FAD-31, manufactured by Seiko Kasei)
13 parts of pH buffer / humidity control polymer fine particles
The drug having the above composition was stirred and mixed well with a disper for 30 minutes, cast on a release paper to a thickness of about 0.15 mm, and cured at 130 ° C. for 2 minutes to foam. The finished foam sheet thickness was 0.5 mm. This foamed urethane sheet had about 10 g of pH buffering / humidifying polymer fine particles per 1 m 2.
[0060]
The results of evaluation of pH buffering and humidity control of the obtained urethane sheet are summarized in Table 2. As shown in the table, it was confirmed that the urethane sheet exhibited good pH buffering and humidity control properties, and the ability of the raw material fine particles was well expressed. Further, the urethane sheet has good retention of the polymer, can be molded into various shapes, and has air permeability, so that it has been a suitable material for filters and the like.
[0061]
Comparative Example 1
Aggregated fine particles containing carboxylic acid groups that were hydrazine-crosslinked were obtained by the same method as in Example 3 except that the hydrolysis with caustic soda was performed at a reaction temperature of 60 ° C. and a reaction time of 1 hour. The pH buffering property and humidity control performance of the particles were evaluated, as shown in Table 3. Since the STD moisture absorption rate was as low as 12% by weight and the moisture absorption rate under drying conditions was also as low as 9% by weight, sufficient humidity control was achieved. No function was expressed. This is considered to be because the amount of carboxylic acid group that brings about hydrophilicity was as low as 0.12 meq / g.
[0062]
[Table 3]

[0063]
Comparative Example 2
Aggregated fine particles containing carboxylic acid groups that were hydrazine-crosslinked were obtained by the same method as in Example 3 except that the crosslinking reaction with hydrazine was performed at 60 ° C. for 0.5 hour. The pH buffering property and humidity control performance of the particles were evaluated as shown in Table 3. The particles having a very high STD moisture absorption of 160% by weight were gel-like, sticky and difficult to handle. . Further, the moisture absorption rate at 20 ° C. and 80% RH was as much as 180% by weight, which was also gel-like and sticky, and could not be handled as a particle powder due to aggregation. Further, the moisture absorption rate after aging for 1 hour at 20 ° C. and 40% RH of the sample is 175% by weight, and there is almost no change from the state of 20 ° C. and 80% RH. Or it was a thing which cannot be used as an additive to a sheet | seat. Moreover, although there was a moisture absorption function, since the moisture release function was hardly recognized, it was functionally insufficient from the point of the humidity control function. As described above, the reason why no change was observed in the moisture absorption rate was the hydrogel (superabsorbent polymer) state, and the surface (particles were solidified and the surface area was extremely small) was dried. However, it is presumed that the central part was protected with a gel and drying did not occur. The reason why such a phenomenon occurred is considered to be that the structure was close to a hydrogel because the crosslinking with hydrazine was very weak.
[0064]
Comparative Example 3
By the same method as in Example 3 except that hydrolysis with caustic soda was performed and the subsequent nitric acid treatment and calcium nitrate treatment were not performed, aggregate-type fine particles in which all carboxyl groups were sodium-type were obtained. The pH buffering properties and humidity control performance of the fine particles were as shown in Table 3, and the humidity control characteristics were good. Further, the buffering action on the acid side was excellent, but the buffering action on the alkali side was not recognized at all.
[0065]
Comparative Example 4
By carrying out the hydrolysis with caustic soda, performing only the subsequent nitric acid treatment, and not carrying out the calcium nitrate treatment, the same method as in Example 3 was used to obtain aggregated fine particles having all carboxyl groups as hydrogen ions. The pH buffering properties and humidity control performance of the fine particles were as shown in Table 3, and the humidity control characteristics were good. However, contrary to Comparative Example 3, although the buffering action on the alkali side was excellent, the buffering action on the acid side was not recognized at all.
[0066]
Examples of cosmetics and comparative examples will be described below. The obtained cosmetics were evaluated for use feeling as follows. About (i) moist feeling, (ii) smooth feeling, (iii) smoothness, (iv) non-stickiness, and (v) smoothing effect based on the judgment of pass / fail when 20 professional panelists apply to the face, According to the following evaluation criteria, it was evaluated in four stages (（, ○, Δ, ×). Furthermore, (vi) smooth feeling continuity and (vii) smoothness continuity were similarly evaluated on a four-stage scale according to the following criteria based on the judgment by a specialized panelist. These results are summarized in Tables 4 and 5.
[0067]
Usability evaluation criteria
◎: 15-20 people judged good feeling
○: 10 to 14 people judged good feeling
Δ: 5 to 9 people judged good feeling
X: Less than 4 people judged that the feeling of use was good
Sustainability criteria
◎ 15-20 people determined that there is a sustainability
○: 10 to 14 people determined that the feeling of use is persistent
Δ: 5 to 9 people determined that the feeling of use is persistent
X: Less than 4 people determined that the feeling of use is persistent
[0068]
Example 8
The raw materials excluding pH buffer / humidity-controlling polymer fine particles according to the formulation shown in Table 4 were heated and stirred for 30 minutes in a reaction vessel adjusted to a temperature of 60 ° C. to 85 ° C. and then cooled to room temperature. Next, the above-mentioned cooled raw material was added to the pH buffer / humidity-controlling polymer fine particles previously stirred with a kneader, and mixed and stirred until uniform, thereby preparing a paste-like cosmetic. The pH buffer / humidity-controlling polymer particles used in Examples 8 and 9 were obtained by pulverizing the aggregate particles obtained in Example 3 with a bead mill to an average particle diameter of 10 μm. The resulting cosmetic was an excellent cosmetic with excellent moist feeling and smoothness and good sustainability.
[0069]
[Table 4]

[0070]
Comparative Example 5
Similarly, as shown in Table 4, paste-like cosmetics were prepared in the same manner as in Example 8 using silicon dioxide fine particles having the same average particle diameter instead of the pH buffer / humidity-adjusting polymer fine particles obtained in Example 3. Created a fee. The smoothness was good, but the moist and smooth feeling was poor, and of course, there was no sustainability. This is considered to be because the added inorganic particles do not have a humidity control function.
[0071]
Comparative Example 6
Similarly, as shown in Table 4, the aggregate fine particles obtained in Comparative Example 1 were pulverized by a bead mill instead of the pH buffer / humidity-adjusting polymer fine particles obtained in Example 3 to obtain an average particle size of 10 μm. A paste-like cosmetic was prepared by the same method as in Example 8. As shown in Table 4, the cosmetics had good tackiness, but were not moist and smooth and had problems with durability. This result is considered to be due to the low humidity control of the fine particles of Comparative Example 1 used.
[0072]
Example 9
Among the formulations shown in Table 5, oil-in-water emulsions were prepared using raw materials excluding guar gum and the pH buffer / humidity-controlling polymer particles obtained in Example 3. Next, guar gum and the particulates were added and mixed by hand to create a smooth cream that could be applied to the skin. As shown in Table 5, the cream was a well-balanced and excellent cosmetic that was particularly excellent in moist feeling, smoothness and smoothing effect, and also excellent in sustainability.
[0073]
[Table 5]

[0074]
Comparative Example 7 and Comparative Example 8
Similarly, as shown in Table 5, a paste-like cosmetic as Comparative Example 7 was prepared by the same method as in the Examples without using pH buffer / humidity-controlling polymer fine particles. Moreover, the cream of the comparative example 8 was created by adding disodium monohydrogen phosphate to the comparative example 7, and adjusting liquid pH to 4.4. As shown in Table 5, the obtained cream has a pH of 6.7 and not a weakly acidic region but a neutral region in Comparative Example 7. As a result, good results are not obtained in any item. Moreover, in Comparative Example 8, the pH is 4.4, which is a weakly acidic region, and the evaluation results tend to be better than Comparative Example 7. However, none of the evaluation items are at a practical level, and a preferable cosmetic is not obtained. . In particular, although a pH buffering agent called monosodium monohydrogen phosphate is added, the buffering action is only in the initial stage, resulting in extremely poor sustainability.
[0075]
Comparative Example 9 and Comparative Example 10
Similarly, as shown in Table 5, in place of the pH buffer / humidity-controlling polymer fine particles obtained in Example 3, the fine particles obtained in Comparative Example 3 were used in Comparative Example 9, and the Comparative Example 10 was used in Comparative Example 4. A cream was prepared using each of the obtained fine particles. Each aggregated fine particle was pulverized by a bead mill to have an average particle diameter of 10 μm. Although the cream of Comparative Example 9 is good in terms of humidity control, it has problems such as high pH, stickiness and lack of sustainability. Further, in the cream of Comparative Example 10, the pH was too much on the acid side, and good results were not obtained in the feeling of use. This is considered to be due to the fact that the fine particles used had no pH buffering property.
[0076]
As described above, compared with the comparative example, the cosmetic using the pH buffer / humidity-controlling polymer fine particles of the present invention has a moist feeling, smooth feeling, smoothness, no stickiness, smoothing effect, smooth feeling sustainability, smoothness Good results have been obtained for both sustainability. These are achieved by the pH buffer function and the humidity control function of the polymer of the present invention, and even when sweating, etc., these excellent effects are maintained rather than the effect of keeping the pH in the stable range of the skin, and the total It is thought that it is an excellent cosmetic.
[0077]
【The invention's effect】
It is a remarkable effect of the present invention that a polymer having both pH buffering property and humidity control property and a means for industrially producing the polymer can be provided. Further, the pH buffer / humidity-controlling polymer of the present invention can take various shapes, for example, it can be used as an additive in the form of powder or beads, or can contain paper, nonwoven fabric or foamed sheet containing these. It can be used in the form. Moreover, it can be set as the cosmetics excellent in total by making this contain in cosmetics.

Claims (8)

In a polymer having an ion-exchangeable polar group and a crosslinked structure derived from a crosslinking agent of either divinylbenzene or triallyl isocyanurate , the moisture absorption rate at 20 ° C. and 65% RH is 15% by weight or more. 100% by weight or less, and the moisture absorption and moisture release characteristics of the polymer that has been saturated and absorbed under conditions of 20 ° C. and 80% RH is a moisture absorption rate of 15% by weight or more after standing at 20 ° C. and 40% RH for 1 hour. A pH characterized by having a moisture conditioning function with a balance of moisture absorption, moisture retention and moisture release of 80% by weight or less, and having a pH range of 4 to 10 obtained by the buffering action of the polymer. Buffering / humidifying polymer. 2. The pH buffer / humidity-controlling polymer according to claim 1, wherein the ion-exchangeable polar group is any one of a sulfonic acid group, a carboxylic acid group, and a phosphoric acid group. The pH buffer / humidity-controlling polymer according to claim 1 or 2 , wherein the polymer is particles having an average particle diameter of 100 µm or less. Polymer, is an aggregate of an average particle size of the primary particles is 5μm or less particles, according to any of claims 1 to 3, wherein the average particle size of the aggregate is 100μm or less PH buffer / humidity control polymer. PH buffering · Humidity polymer according to claim 1, wherein the exchange capacity of the ion exchange of the polar group is 2.0 meq / g or more 4. As a counter ion of the ion exchange of polar groups, according to any of the hydrogen ions and metal ions Ca, Mg, Na, K, Li, claim 1, characterized in that it comprises any of the Al 5 PH buffer / humidity control polymer. A pH buffer / humidity-controlling polymer-containing sheet, which is any one of a paper, a nonwoven fabric, and a foamed sheet containing the pH buffering / humidity-controlling polymer according to any one of claims 1 to 6 . A cosmetic comprising the pH buffering / humidifying polymer according to any one of claims 1 to 6 .