JP4502344B2 - Gypsum dispersant - Google Patents
Gypsum dispersant Download PDFInfo
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- JP4502344B2 JP4502344B2 JP2000179410A JP2000179410A JP4502344B2 JP 4502344 B2 JP4502344 B2 JP 4502344B2 JP 2000179410 A JP2000179410 A JP 2000179410A JP 2000179410 A JP2000179410 A JP 2000179410A JP 4502344 B2 JP4502344 B2 JP 4502344B2
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- gypsum
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- dispersant
- vinyl monomer
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- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B28/00—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements
- C04B28/14—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements containing calcium sulfate cements
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B24/00—Use of organic materials as active ingredients for mortars, concrete or artificial stone, e.g. plasticisers
- C04B24/24—Macromolecular compounds
- C04B24/26—Macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
- C04B24/2664—Macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds of ethylenically unsaturated dicarboxylic acid polymers, e.g. maleic anhydride copolymers
- C04B24/267—Macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds of ethylenically unsaturated dicarboxylic acid polymers, e.g. maleic anhydride copolymers containing polyether side chains
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2103/00—Function or property of ingredients for mortars, concrete or artificial stone
- C04B2103/0045—Polymers chosen for their physico-chemical characteristics
- C04B2103/0059—Graft (co-)polymers
- C04B2103/006—Comb polymers
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2103/00—Function or property of ingredients for mortars, concrete or artificial stone
- C04B2103/40—Surface-active agents, dispersants
- C04B2103/408—Dispersants
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Ceramic Engineering (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Materials Engineering (AREA)
- Structural Engineering (AREA)
- Organic Chemistry (AREA)
- Inorganic Chemistry (AREA)
- Emulsifying, Dispersing, Foam-Producing Or Wetting Agents (AREA)
- Curing Cements, Concrete, And Artificial Stone (AREA)
- Macromonomer-Based Addition Polymer (AREA)
Description
【０００１】
【発明の属する技術分野】
本発明は石膏用分散剤に関する。石膏ボード、石膏プラスター、石膏ブロック等、各種の石膏成形物が使用されている。これらの石膏成形物は一般に、石膏スラリーを調製し、これを型枠内へ注入して、乾燥及び凝結硬化させる方法により製造されている。かかる石膏成形物の製造では、石膏スラリーを型枠内へ流し込み易くするため、石膏スラリーに充分な流動性を付与する必要がある。石膏スラリーの流動性を高くする方法としては、これを調製する際に使用する水の量を増やし、水／石膏比を高くすることが考えられるが、このようにすると、得られる石膏成形物が強度の低いものになってしまう。そこで、水の量を増やさずに石膏スラリーの流動性を高めるため、石膏用分散剤が使用されるようになっている。
本発明はかかる石膏用分散剤の改良に関する。
【０００２】
【従来の技術】
従来、上記のような石膏用分散剤として、リグニンスルホン酸塩、ナフタレンスルホン酸ホルマリン高縮合物塩、メラミンスルホン酸ホルマリン高縮合物塩、ポリスチレンスルホン酸塩（特開平１−１８８４４８）、水溶性ビニル共重合体（特開平２−１６３１０８、特開平８−２１７５０５）等が知られている。しかし、これら従来の石膏用分散剤には、石膏スラリーに充分な流動性を付与できないという問題があり、特に水の使用量が少なく、したがって水／石膏比の低い石膏スラリーに対し流動性の付与が不充分という問題がある。
【０００３】
【発明が解決しようとする課題】
本発明が解決しようとする課題は、水の使用量が少ない、したがって水／石膏比の低い石膏スラリーに対しても、少量の使用量で充分な流動性を付与できる石膏用分散剤を提供する処にある。
【０００４】
【課題を解決するための手段】
しかして本発明者らは、上記の課題を解決するべく研究した結果、特定の３種のビニル単量体を所定割合で共重合反応させて得られる、重量平均分子量が所定範囲内の水溶性ビニル共重合体が石膏用分散剤として正しく好適であることを見出した。
【０００５】
すなわち本発明は、下記の式１で示されるビニル単量体Ａを０．１〜４５モル％、下記の式２で示されるビニル単量体Ｂを５〜５５モル％及び下記の式３で示されるビニル単量体Ｃを４０〜６０モル％（合計１００モル％）の割合で共重合反応させて得られる、ＧＰＣ法によるプルラン換算の重量平均分子量が１０００〜１０００００の水溶性ビニル共重合体から成ることを特徴とする石膏用分散剤に係る。
【０００６】
【式１】
式１〜式３において、
Ｒ1：水素、炭素数１〜１８の脂肪族炭化水素基、フェニル基又はベンジル基
Ｒ2，Ｒ3，Ｒ5，Ｒ6：水素又はメチル基
Ｒ4：水素又は−ＣＯ2Ｍ3で示される有機基（Ｍ3；水素、アルカリ金属、アルカリ土類金属、アンモニウム又は有機アミン）
Ｍ1，Ｍ2：水素、アルカリ金属、アルカリ土類金属、アンモニウム又は有機アミン
Ａ1：合計２〜４００個のオキシエチレン単位とオキシプロピレン単位とで構成されたポリオキシアルキレン基
Ａ2：１〜８０個のオキシエチレン単位、１〜８０個のオキシプロピレン単位又は合計２〜８０個のオキシエチレン単位とオキシプロピレン単位とで構成された（ポリ）オキシアルキレン基
【０００８】
式１で示されるビニル単量体Ａとしては、いずれも式１中のＡ１で示されるポリオキシアルキレン基を構成するオキシエチレン単位とオキシプロピレン単位の合計数が２〜４００個である、１）炭素数１〜１８の脂肪族炭化水素基で末端封鎖された末端封鎖ポリアルキレングリコールマレイン酸モノエステル、２）フェノキシポリアルキレングリコールマレイン酸モノエステル、３）ベンジルオキシポリアルキレングリコールマレイン酸モノエステル、４）ポリアルキレングリコールマレイン酸モノエステル、５）上記１）〜４）の塩が挙げられる。５）の塩を形成する塩基としては、ａ）ナトリウム、カリウム等のアルカリ金属、ｂ）カルシウム、マグネシウム等のアルカリ土類金属、ｃ）アンモニウム、ｄ）ジエタノールアミン、トリエタノールアミン等の有機アミンが挙げられる。なかでも、合計１０１〜２５０個のオキシエチレン単位とオキシプロピレン単位とで構成されたポリオキシアルキレン基を有するものが好ましく、かかるポリオキシアルキレン基を有する末端封鎖ポリアルキレングリコールマレイン酸モノエステルのアルカリ金属塩がより好ましい。
【０００９】
式２で示されるビニル単量体Ｂとしては、１）アクリル酸、メタクリル酸、クロトン酸、イタコン酸等の１塩基酸、２）マレイン酸、フマル酸、シトラコン酸等の２塩基酸、３）上記１）又は２）の塩が挙げられる。３）の塩を形成する塩基としては、式１で示される構成単位Ａの場合と同じである。なかでも、アクリル酸、マレイン酸、これらのアルカリ金属塩が好ましい。
【００１０】
式３で示されるビニル単量体Ｃとしては、１）（ポリ）オキシアルキレンモノアリルエーテル、２）（ポリ）オキシアルキレンモノメタリルエーテル、３）メトキシ（ポリ）オキシアルキレンアリルエーテル、４）メトキシ（ポリ）オキシアルキレンメタリルエーテルが挙げられる。式３中のＡ2で示される（ポリ）オキシアルキレン基には、ａ）オキシエチレン単位のみで構成された（ポリ）オキシエチレン基、ｂ）オキシプロピレン単位のみで構成された（ポリ）オキシプロピレン基、ｃ）オキシエチレン単位とオキシプロピレン単位とで構成された（ポリ）オキシエチレン（ポリ）オキシプロピレン基があるが、ａ）の（ポリ）オキシエチレン基が好ましい。ｃ）の場合、オキシエチレン単位とオキシプロピレン単位の結合様式はランダム状でも或はブロック状でもよい。いずれの場合においてもポリオキシアルキレン基を構成するオキシアルキレン単位の合計数は１〜８０個とするが、５〜４０個とするのが好ましい。
【００１１】
本発明の石膏用分散剤としての水溶性ビニル共重合体は、ラジカル開始剤の存在下に、それぞれ所定割合のビニル単量体Ａ〜Ｃをラジカル共重合することにより得られる。ラジカル共重合は、水又は水と水溶性有機溶媒との混合溶媒を用いた水系溶液重合により行なうことができる。より具体的には、先ずビニル単量体Ａ〜Ｃを所定割合で水に溶解し、ビニル単量体Ａ〜Ｃを合計量として３０〜７０重量％含む水溶液を調製する。次に窒素ガス雰囲気下において、該水溶液にラジカル開始剤を加え、６０〜９０℃で６〜１２時間ラジカル共重合反応させて、水溶性ビニル共重合体を得ることができる。用いるラジカル開始剤としては、共重合反応温度下において分解し、ラジカル発生するものであればその種類は特に制限されないが、水溶性のラジカル開始剤を用いるのが好ましい。かかる水溶性のラジカル開始剤としては、過硫酸カリウム、過硫酸アンモニウム等の過硫酸塩、過酸化水素、２，２−アゾビス（２−アミジノプロパン）二塩酸塩等が挙げられる。これらは、亜硫酸塩やＬ−アスコルビン酸の如き還元性物質更にはアミン等と組み合わせ、レドックス開始剤として用いることもできる。得られる水溶性ビニル共重合体混合物の重量平均分子量を所望の範囲とするため、２−メルカプトエタノール、２−メルカプトプロピオン酸、３−メルカプトプロピオン酸、チオグリコール酸、チオグリセリン等の連鎖移動剤を使用することもできる。
【００１２】
本発明の石膏用分散剤としての水溶性ビニル共重合体は、ビニル単量体Ａを０．１〜４５モル％、好ましくは０．３〜４０モル％、ビニル単量体Ｂを５〜５５モル％、好ましくは１２〜５０モル％、ビニル単量体Ｃを４０〜６０モル％、好ましくは４５〜５５モル％（合計１００モル％）の割合で共重合反応させて得られるものである。またそのＧＰＣ（ゲルパーミエーションクロマトグラフィー）法によるプルラン換算の重量平均分子量（以下、重量平均分子量は同じ）は１０００〜１０００００の範囲内のものとするが、好ましくは１００００〜５００００の範囲内のものとする。
【００１３】
本発明の石膏用分散剤として用いる水溶性ビニル共重合体は、以上説明したようにビニル単量体Ａ〜Ｃを所定割合で共重合反応させて得られる所定の重量平均分子量を有するものであるが、分子中にオキシエチレン単位とオキシプロピレン単位とで構成されたポリオキシアルキレン基を有するビニル単量体Ａを共重合反応させるところに特長を有する。
【００１４】
本発明の石膏用分散剤としての水溶性ビニル共重合体は、石膏スラリーを調製する際に使用される。石膏スラリーの主材となる石膏には、半水石膏、二水石膏、無水石膏の外に、リン酸石膏、フッ酸石膏等の副産石膏がある。かかる石膏を主材とする石膏スラリーの調製に際して、本発明の石膏用分散剤としての水溶性ビニル共重合体は、石膏に対し、通常は０．０５〜１．５重量％の割合となるよう使用するが、好ましくは０．１〜１．０重量％の割合となるよう使用する。
【００１５】
本発明の石膏用分散剤としての水溶性ビニル共重合体は、水の使用量が少ない、したがって水／石膏比が低い、より具体的には重量換算の水／石膏比が２０〜８５％の石膏スラリーに対しても、少量の使用量で充分な流動性を付与できる。
【００１６】
【発明の実施の形態】
本発明の実施形態としては、次の１）〜４）が挙げられる。
１）メトキシポリプロピレングリコール（オキシプロピレン単位の数＝４０、以下ｍ＝４０という）ポリエチレングリコール（オキシエチレン単位の数＝７０、以下ｎ＝７０という）マレイン酸モノエステルナトリウム塩（Ａ−１）を４モル％、マレイン酸ナトリウム塩（Ｂ−１）を４６モル％及びメトキシポリエチレングリコール（ｎ＝７）アリルエーテル（Ｃ−１）を５０モル％（合計１００モル％）の割合で共重合反応させて得られる重量平均分子量１２８００の水溶性ビニル共重合体から成る石膏用分散剤。
【００１７】
２）メトキシポリプロピレングリコール（ｍ＝４０）ポリエチレングリコール（ｎ＝７０）マレイン酸モノエステルナトリウム塩（Ａ−１）を１６モル％、マレイン酸ナトリウム塩（Ｂ−１）を３０モル％、ポリエチレングリコール（ｎ＝２３）モノアリルエーテル（Ｃ−２）を５４モル％（合計１００モル％）の割合で共重合反応させて得られる重量平均分子量１０５００の水溶性ビニル共重合体から成る石膏用分散剤。
【００１８】
３）メトキシポリプロピレングリコール（ｍ＝６０）ポリエチレングリコール（ｎ＝９０）マレイン酸モノエステルナトリウム塩（Ａ−２）を７モル％、マレイン酸ナトリウム塩（Ｂ−１）を４７モル％、ポリエチレングリコール（ｎ＝５０）アリルエーテル（Ｃ−３）を４６モル％（合計１００モル％）の割合で共重合反応させて得られる重量平均分子量２３６００の水溶性ビニル共重合体から成る石膏用分散剤。
【００１９】
４）フェノキシポリプロピレングリコール（ｍ＝５０）ポリエチレングリコール（ｎ＝１８０）マレイン酸モノエステルナトリウム塩（Ａ−４）を１モル％、アクリル酸ナトリウム塩（Ｂ−２）を４９モル％、ポリエチレングリコール（ｎ＝７）アリルエーテル（Ｃ−１）を５０モル％（合計１００モル％）の割合で共重合反応させて得られる重量平均分子量４８０００の水溶性ビニル共重合体から成る石膏用分散剤。
【００２０】
以下、本発明の構成及び効果をより具体的にするため、実施例等を挙げるが、本発明が該実施例に限定されるというものではない。尚、以下の実施例等において、別に記載しない限り、部は重量部を、また％は空気量を除き重量％を意味する。
【００２１】
【実施例】
試験区分１（石膏用分散剤としての水溶性ビニル共重合体の合成）
・実施例１
メトキシポリプロピレングリコール（ｍ＝４０）ポリエチレングリコール（ｎ＝７０）マレイン酸モノエステル２２２部（０．０４モル）、マレイン酸５３部（０．４６モル）、メトキシポリエチレングリコール（ｎ＝７）アリルエーテル１９０部（０．５０モル）及び水５３１部を反応容器に仕込み、撹拌しながら均一に溶解した後、雰囲気を窒素置換した。反応系の温度を温水浴にて８５℃に保ち、過硫酸ナトリウムの１０％水溶液３０部を３時間かけて滴下した。更に１時間撹拌を続けた後、過硫酸ナトリウムの１０％水溶液１０部を２時間かけて滴下し、共重合反応を完結した。反応系に３０％水酸化ナトリウム水溶液１２９部を投入して完全中和し、生成物を得た。得られた生成物は重量平均分子量１２８００の水溶性ビニル共重合体であった。
【００２２】
・実施例２〜１２及び比較例３〜９
実施例１の水溶性ビニル共重合体と同様にして、実施例２〜１２及び比較例３〜９の水溶性ビニル共重合体を得た。
【００２３】
・比較例１
マレイン酸５８部（０．５０モル）、メトキシポリエチレングリコール（ｎ＝７）アリルエーテル１９０部（０．５０モル）及び水２１１部を反応容器に仕込み、撹拌しながら均一に溶解した後、雰囲気を窒素置換した。反応系の温度を温水浴にて８５℃に保ち、過硫酸ナトリウムの１０％水溶液１９部を３時間かけて滴下した。更に１時間撹拌を続けた後、過硫酸ナトリウムの１０％水溶液６部を２時間かけて滴下し、共重合反応を完結した。反応系に３０％水酸化ナトリウム水溶液１３３部を投入して完全中和し、生成物を得た。得られた生成物は重量平均分子量２５７００の水溶性ビニル共重合体であった。
【００２４】
・比較例２
比較例１の水溶性ビニル共重合体と同様にして、比較例２の水溶性ビニル共重合体を得た。
以上で合成した各水溶性ビニル共重合体の内容を表１にまとめて示した。また各水溶性ビニル共重合体の合成に用いたビニル単量体の内容を表２〜表４にまとめて示した。
【００２５】
【表１】
【表２】
【表３】
【表４】
試験区分２（石膏スラリーの調製及び評価）
・石膏スラリーの調製
表５に記載した各試験例の石膏スラリーを次のように調製した。５０リットルのホバートミキサーに半水石膏（丸石石膏社製の陶磁器型材用焼石膏グレードＡ級）２０００部、水１０７７部及び試験区分１で合成した石膏用分散剤としての水溶性ビニル共重合体等の３０％水溶液を表５に記載した使用量となるよう順次投入して３分間練り混ぜた。ここで調製した石膏スラリーは、試験例２５を除き、重量換算の水／石膏比が５４％である。
【００３０】
・石膏スラリーの評価
調製した各試験例の石膏スラリーについて、次のように評価し、結果を表５にまとめて示した。
フロー値（mm）：ＪＩＳ−Ｒ５２０１にしたがい、フローコーンに石膏スラリーを充填し、フローコーンを持ち上げた後の石膏スラリーの広がりの直径を２箇所測定して、その平均値をフロー値とした。
フロー増加率（％）：［｛（各試験例のフロー値）−（ブランクとしての試験例１３のフロー値）｝／ブランクとしての試験例１３のフロー値］×１００
圧縮強度（ＭＰａ）：上記で調製した石膏スラリーを用いて作製した４×４×１６cmの供試体を温度２０℃で湿度８０％の条件下に１時間養生した後、その圧縮強度をＪＩＳ−Ｒ５２０１にしたがい測定した。
【００３１】
【表５】
表５において、
石膏用分散剤の使用量：石膏に対する使用した石膏用分散剤としての水溶性ビニル共重合体等の固形分換算の重量％
試験例１３：石膏用分散剤を使用しなかった例（ブランク）
比較例１０：ナフタレンスルホン酸系分散剤（竹本油脂社製の商品名ポールファイン５１０−ＡＮ）
比較例１１：ポリカルボン酸系分散剤（竹本油脂社製の商品名チューポールＨＰ−１１）
試験例２５：重量換算の水／石膏比が９０％の石膏スラリー
【００３３】
【発明の効果】
既に明らかなように、以上説明した本発明には、水の使用量が少ない、したがって水／石膏比の低い石膏スラリーに対しても、少量の使用量で充分な流動性を付与できるという効果がある。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a dispersant for gypsum. Various gypsum moldings such as gypsum board, gypsum plaster and gypsum block are used. These gypsum moldings are generally produced by a method in which a gypsum slurry is prepared, poured into a mold, and dried and coagulated. In the production of such a gypsum molding, it is necessary to impart sufficient fluidity to the gypsum slurry in order to facilitate the pouring of the gypsum slurry into the mold. As a method for increasing the fluidity of the gypsum slurry, it is conceivable to increase the amount of water used in preparing the gypsum slurry and increase the water / gypsum ratio. It will be low strength. Therefore, a gypsum dispersant is used to increase the fluidity of the gypsum slurry without increasing the amount of water.
The present invention relates to an improvement of such a gypsum dispersant.
[0002]
[Prior art]
Conventionally, as a dispersant for gypsum as described above, lignin sulfonate, naphthalene sulfonic acid formalin high condensate salt, melamine sulfonic acid formalin high condensate salt, polystyrene sulfonate (JP-A-1-188448), water-soluble vinyl Copolymers (JP-A-2-163108, JP-A-8-217505) and the like are known. However, these conventional gypsum dispersants have a problem in that they cannot impart sufficient fluidity to the gypsum slurry, and in particular, impart low fluidity to gypsum slurries that have a low amount of water and therefore have a low water / gypsum ratio. There is a problem of insufficient.
[0003]
[Problems to be solved by the invention]
The problem to be solved by the present invention is to provide a gypsum dispersant capable of imparting sufficient fluidity to a gypsum slurry with a low water / gypsum ratio, and thus with a small amount of use. There is in place.
[0004]
[Means for Solving the Problems]
As a result, the present inventors have studied to solve the above-mentioned problems, and as a result, obtained by copolymerization reaction of specific three kinds of vinyl monomers at a predetermined ratio, water-soluble having a weight average molecular weight within a predetermined range. It has been found that vinyl copolymers are correctly suitable as a dispersant for gypsum.
[0005]
That is, the present invention provides 0.1 to 45 mol% of the vinyl monomer A represented by the following formula 1, 5 to 55 mol% of the vinyl monomer B represented by the following formula 2 and A water-soluble vinyl copolymer having a weight average molecular weight in terms of pullulan calculated by the GPC method of 1000 to 100,000, obtained by copolymerizing the indicated vinyl monomer C at a ratio of 40 to 60 mol% (total of 100 mol%). It is related with the dispersing agent for gypsum characterized by comprising.
[0006]
[Formula 1]
In Equations 1 to 3,
R 1 : hydrogen, aliphatic hydrocarbon group having 1 to 18 carbon atoms, phenyl group or benzyl group R 2 , R 3 , R 5 , R 6 : hydrogen or methyl group R 4 : represented by hydrogen or —CO 2 M 3 Organic group (M 3 ; hydrogen, alkali metal, alkaline earth metal, ammonium or organic amine)
M 1 , M 2 : hydrogen, alkali metal, alkaline earth metal, ammonium or organic amine A 1 : polyoxyalkylene group A 2 composed of a total of 2 to 400 oxyethylene units and oxypropylene units: 1 to 1 (Poly) oxyalkylene group composed of 80 oxyethylene units, 1 to 80 oxypropylene units, or a total of 2 to 80 oxyethylene units and oxypropylene units
As the vinyl monomer A represented by the formula 1, the total number of oxyethylene units and oxypropylene units constituting the polyoxyalkylene group represented by A 1 in the formula 1 is 2 to 400. ) end-capped polyalkylene glycol maleic acid monoester is end-capped with an aliphatic hydrocarbon group having 1 to 18 carbon atoms, 2) phenoxypoly alkylene glycol monoester of maleic acid, 3) benzyloxy polyalkylene glycol maleic acid monoester, 4) a polyalkylene glycol maleic acid monoester, 5) salts of the 1) to 4) below. Examples of the base that forms the salt of 5) include a) alkali metals such as sodium and potassium, b) alkaline earth metals such as calcium and magnesium, c) ammonium, d) organic amines such as diethanolamine and triethanolamine. It is done. Of these, a total of 101 to 250 oxyethylene units and preferably has a configuration polyoxyalkylene group and oxypropylene units, end-capped polyalkylene glycols alkali maleic acid monoester having such polyoxyalkylene group Metal salts are more preferred.
[0009]
As the vinyl monomer B represented by the formula 2, 1) monobasic acids such as acrylic acid, methacrylic acid, crotonic acid and itaconic acid, 2) dibasic acids such as maleic acid, fumaric acid and citraconic acid, and 3) The salt of said 1) or 2) is mentioned. The base that forms the salt of 3) is the same as in the case of the structural unit A represented by Formula 1. Of these, acrylic acid, maleic acid, and alkali metal salts thereof are preferable.
[0010]
As the vinyl monomer C represented by the formula 3, 1) (poly) oxyalkylene monoallyl ether, 2) (poly) oxyalkylene monomethallyl ether, 3) methoxy (poly) oxyalkylene allyl ether, 4) methoxy ( Poly) oxyalkylene methallyl ether. The (poly) oxyalkylene group represented by A 2 in Formula 3 includes a) a (poly) oxyethylene group composed only of oxyethylene units, and b) a (poly) oxypropylene composed only of oxypropylene units. Group c) there is a (poly) oxyethylene (poly) oxypropylene group composed of oxyethylene units and oxypropylene units, with the (poly) oxyethylene group of a) being preferred. In the case of c), the bonding mode of oxyethylene units and oxypropylene units may be random or block. In any case, the total number of oxyalkylene units constituting the polyoxyalkylene group is 1 to 80, preferably 5 to 40.
[0011]
The water-soluble vinyl copolymer as the gypsum dispersant of the present invention can be obtained by radical copolymerizing a predetermined proportion of vinyl monomers A to C, respectively, in the presence of a radical initiator. The radical copolymerization can be performed by aqueous solution polymerization using water or a mixed solvent of water and a water-soluble organic solvent. More specifically, first, vinyl monomers A to C are dissolved in water at a predetermined ratio to prepare an aqueous solution containing 30 to 70% by weight of vinyl monomers A to C as a total amount. Next, in a nitrogen gas atmosphere, a radical initiator is added to the aqueous solution, and a radical copolymerization reaction is performed at 60 to 90 ° C. for 6 to 12 hours to obtain a water-soluble vinyl copolymer. The radical initiator to be used is not particularly limited as long as it decomposes at the copolymerization reaction temperature and generates radicals, but a water-soluble radical initiator is preferably used. Examples of such a water-soluble radical initiator include persulfates such as potassium persulfate and ammonium persulfate, hydrogen peroxide, 2,2-azobis (2-amidinopropane) dihydrochloride, and the like. These can also be used as a redox initiator in combination with a reducing substance such as sulfite or L-ascorbic acid, or an amine. A chain transfer agent such as 2-mercaptoethanol, 2-mercaptopropionic acid, 3-mercaptopropionic acid, thioglycolic acid, thioglycerin, etc. is used in order to bring the weight average molecular weight of the resulting water-soluble vinyl copolymer mixture into a desired range. It can also be used.
[0012]
The water-soluble vinyl copolymer as a dispersant for gypsum of the present invention has a vinyl monomer A content of 0.1 to 45 mol%, preferably 0.3 to 40 mol%, and a vinyl monomer B content of 5 to 55. It is obtained by carrying out a copolymerization reaction in a proportion of mol%, preferably 12 to 50 mol%, and vinyl monomer C in a proportion of 40 to 60 mol%, preferably 45 to 55 mol% (total 100 mol%). The weight average molecular weight (hereinafter, the same weight average molecular weight) in terms of pullulan by GPC (gel permeation chromatography) method is in the range of 1000 to 100,000, preferably in the range of 10,000 to 50,000. And
[0013]
The water-soluble vinyl copolymer used as the gypsum dispersant of the present invention has a predetermined weight average molecular weight obtained by copolymerizing vinyl monomers A to C at a predetermined ratio as described above. However, it is characterized in that a vinyl monomer A having a polyoxyalkylene group composed of oxyethylene units and oxypropylene units in the molecule is copolymerized.
[0014]
The water-soluble vinyl copolymer as a dispersant for gypsum of the present invention is used when preparing a gypsum slurry. In addition to hemihydrate gypsum, dihydrate gypsum, and anhydrous gypsum, by-product gypsum such as phosphate gypsum and hydrofluoric acid gypsum is used as the main material of the gypsum slurry. When preparing a gypsum slurry containing gypsum as a main material, the water-soluble vinyl copolymer as a gypsum dispersant of the present invention is usually in a proportion of 0.05 to 1.5% by weight with respect to gypsum. Although it is used, it is preferably used in a proportion of 0.1 to 1.0% by weight.
[0015]
The water-soluble vinyl copolymer as a gypsum dispersant of the present invention has a small amount of water used, and therefore has a low water / gypsum ratio, more specifically, a weight-converted water / gypsum ratio of 20 to 85%. Sufficient fluidity can be imparted to the gypsum slurry with a small amount of use.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Examples of the present invention include the following 1) to 4).
1) Methylene polypropylene glycol (number of oxypropylene units = 40, hereinafter referred to as m = 40) polyethylene glycol (number of oxyethylene units = 70, hereinafter referred to as n = 70) maleic acid monoester sodium salt (A-1) 4 The copolymerization reaction was carried out at a ratio of mol%, 46 mol% of maleic acid sodium salt (B-1) and 50 mol% (total 100 mol%) of methoxypolyethylene glycol (n = 7) allyl ether (C-1). A gypsum dispersant comprising a water-soluble vinyl copolymer having a weight average molecular weight of 12,800.
[0017]
2) Methoxypolypropylene glycol (m = 40) polyethylene glycol (n = 70) 16 mol% of maleic acid monoester sodium salt (A-1), 30 mol% of maleic acid sodium salt (B-1), polyethylene glycol ( n = 23) A dispersing agent for gypsum comprising a water-soluble vinyl copolymer having a weight average molecular weight of 10500, obtained by copolymerizing 54 mol% (total 100 mol%) of monoallyl ether (C-2).
[0018]
3) Methoxypolypropylene glycol (m = 60) polyethylene glycol (n = 90) 7 mol% of maleic acid monoester sodium salt (A-2), 47 mol% of maleic acid sodium salt (B-1), polyethylene glycol ( n = 50) A dispersant for gypsum comprising a water-soluble vinyl copolymer having a weight average molecular weight of 23,600 obtained by copolymerization reaction of allyl ether (C-3) at a ratio of 46 mol% (100 mol% in total).
[0019]
4) Phenoxypolypropylene glycol (m = 50) polyethylene glycol (n = 180) 1 mol% of maleic acid monoester sodium salt (A-4), 49 mol% of acrylic acid sodium salt (B-2), polyethylene glycol ( n = 7) A gypsum dispersant comprising a water-soluble vinyl copolymer having a weight average molecular weight of 48,000 obtained by copolymerization reaction of allyl ether (C-1) at a ratio of 50 mol% (total 100 mol%).
[0020]
Hereinafter, in order to make the configuration and effects of the present invention more specific, examples and the like will be described. However, the present invention is not limited to the examples. In the following examples and the like, unless otherwise indicated, parts means parts by weight, and% means% by weight excluding the amount of air.
[0021]
【Example】
Test Category 1 (Synthesis of water-soluble vinyl copolymer as a dispersant for gypsum)
Example 1
Methoxypolypropylene glycol (m = 40) polyethylene glycol (n = 70) maleic acid monoester 222 parts (0.04 mol), maleic acid 53 parts (0.46 mol), methoxypolyethylene glycol (n = 7) allyl ether 190 Parts (0.50 mol) and 531 parts of water were charged in a reaction vessel and dissolved uniformly with stirring, and the atmosphere was replaced with nitrogen. The temperature of the reaction system was kept at 85 ° C. in a warm water bath, and 30 parts of a 10% aqueous solution of sodium persulfate was added dropwise over 3 hours. After further stirring for 1 hour, 10 parts of a 10% aqueous solution of sodium persulfate was added dropwise over 2 hours to complete the copolymerization reaction. 129 parts of a 30% aqueous sodium hydroxide solution was added to the reaction system to completely neutralize it to obtain a product. The obtained product was a water-soluble vinyl copolymer having a weight average molecular weight of 12,800.
[0022]
-Examples 2-12 and Comparative Examples 3-9
In the same manner as the water-soluble vinyl copolymer of Example 1, water-soluble vinyl copolymers of Examples 2 to 12 and Comparative Examples 3 to 9 were obtained.
[0023]
Comparative example 1
58 parts (0.50 mol) of maleic acid, 190 parts (0.50 mol) of methoxypolyethylene glycol (n = 7) allyl ether and 211 parts of water were charged into a reaction vessel and dissolved uniformly with stirring. Replaced with nitrogen. The temperature of the reaction system was kept at 85 ° C. in a warm water bath, and 19 parts of a 10% aqueous solution of sodium persulfate was added dropwise over 3 hours. After further stirring for 1 hour, 6 parts of a 10% aqueous solution of sodium persulfate was added dropwise over 2 hours to complete the copolymerization reaction. The reaction system was completely neutralized by adding 133 parts of 30% aqueous sodium hydroxide solution to obtain a product. The obtained product was a water-soluble vinyl copolymer having a weight average molecular weight of 25,700.
[0024]
Comparative example 2
A water-soluble vinyl copolymer of Comparative Example 2 was obtained in the same manner as the water-soluble vinyl copolymer of Comparative Example 1.
The contents of each water-soluble vinyl copolymer synthesized above are summarized in Table 1. The contents of vinyl monomers used for the synthesis of each water-soluble vinyl copolymer are summarized in Tables 2 to 4.
[0025]
[Table 1]
[Table 2]
[Table 3]
[Table 4]
Test category 2 (Preparation and evaluation of gypsum slurry)
-Preparation of gypsum slurry The gypsum slurry of each test example described in Table 5 was prepared as follows. Water-soluble vinyl copolymer as a dispersing agent for gypsum synthesized in 2000 liters of Hobart mixer, 2000 parts of hemihydrate gypsum (Ceramic mold gypsum grade A grade for ceramic molds, 1077 parts of water, test category 1) 30% aqueous solutions were sequentially added so as to have the use amounts shown in Table 5, and kneaded for 3 minutes. The gypsum slurry prepared here has a water / gypsum ratio in terms of weight of 54%, except for Test Example 25.
[0030]
-Evaluation of gypsum slurry The gypsum slurry of each test example prepared was evaluated as follows, and the results are summarized in Table 5.
Flow value (mm): According to JIS-R5201, the flow cone was filled with gypsum slurry, the diameter of the spread of the gypsum slurry after lifting the flow cone was measured at two locations, and the average value was taken as the flow value.
Flow increase rate (%): [{(flow value of each test example) − (flow value of test example 13 as blank)}} / flow value of test example 13 as blank] × 100
Compressive strength (MPa): After a 4 × 4 × 16 cm specimen prepared using the gypsum slurry prepared above was cured at a temperature of 20 ° C. and a humidity of 80% for 1 hour, the compressive strength was measured according to JIS-R5201. Measured according to
[0031]
[Table 5]
In Table 5,
Amount of dispersant for gypsum:% by weight in terms of solid content of water-soluble vinyl copolymer as a gypsum dispersant used for gypsum
Test Example 13: Example of using no gypsum dispersant (blank)
Comparative Example 10: Naphthalenesulfonic acid dispersant (trade name Pole Fine 510-AN manufactured by Takemoto Yushi Co., Ltd.)
Comparative Example 11: Polycarboxylic acid dispersant (trade name Tupol HP-11 manufactured by Takemoto Yushi Co., Ltd.)
Test Example 25: Gypsum slurry having a water / gypsum ratio of 90% by weight
【The invention's effect】
As is apparent from the above, the present invention described above has the effect that a sufficient amount of fluidity can be imparted to a gypsum slurry with a small amount of water, and thus a low amount of water / gypsum ratio. is there.
Claims (7)
【式１】
Ｒ1：水素、炭素数１〜１８の脂肪族炭化水素基、フェニル基又はベンジル基
Ｒ2，Ｒ3，Ｒ5，Ｒ6：水素又はメチル基
Ｒ4：水素又は−ＣＯ2Ｍ3で示される有機基（Ｍ3；水素、アルカリ金属、アルカリ土類金属、アンモニウム又は有機アミン）
Ｍ1，Ｍ2：水素、アルカリ金属、アルカリ土類金属、アンモニウム又は有機アミン
Ａ1：合計２〜４００個のオキシエチレン単位とオキシプロピレン単位とで構成されたポリオキシアルキレン基
Ａ2：１〜８０個のオキシエチレン単位、１〜８０個のオキシプロピレン単位又は合計２〜８０個のオキシエチレン単位とオキシプロピレン単位とで構成された（ポリ）オキシアルキレン基］0.1 to 45 mol% of the vinyl monomer A represented by the following formula 1, 5 to 55 mol% of the vinyl monomer B represented by the following formula 2 and the vinyl monomer represented by the following formula 3 It is characterized by comprising a water-soluble vinyl copolymer having a weight average molecular weight of 1000 to 100,000 in terms of pullulan calculated by GPC method, obtained by copolymerizing the product C at a ratio of 40 to 60 mol% (total 100 mol%). Dispersant for gypsum.
[Formula 1]
R 1 : hydrogen, aliphatic hydrocarbon group having 1 to 18 carbon atoms, phenyl group or benzyl group R 2 , R 3 , R 5 , R 6 : hydrogen or methyl group R 4 : represented by hydrogen or —CO 2 M 3 Organic group (M 3 ; hydrogen, alkali metal, alkaline earth metal, ammonium or organic amine)
M 1 , M 2 : hydrogen, alkali metal, alkaline earth metal, ammonium or organic amine A 1 : polyoxyalkylene group A 2 composed of a total of 2 to 400 oxyethylene units and oxypropylene units: 1 to 1 (Poly) oxyalkylene group composed of 80 oxyethylene units, 1 to 80 oxypropylene units, or a total of 2 to 80 oxyethylene units and oxypropylene units]
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| CA2477709C (en) * | 2002-03-27 | 2011-02-01 | United States Gypsum Company | High molecular weight additives for calcined gypsum and cementitious compositions |
| US7572328B2 (en) * | 2005-06-14 | 2009-08-11 | United States Gypsum Company | Fast drying gypsum products |
| WO2019053782A1 (en) * | 2017-09-12 | 2019-03-21 | 竹本油脂株式会社 | Dispersion-maintaining agent for hydraulic composition |
| JP7124083B2 (en) * | 2017-12-13 | 2022-08-23 | クナウフ ギプス カーゲー | Gypsum composition with enhanced resistance to permanent set |
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|---|---|---|---|---|
| JPH02163108A (en) * | 1988-12-16 | 1990-06-22 | Nippon Oil & Fats Co Ltd | Polyoxyalkylene unsaturated ether-maleic acid ester copolymer and use thereof |
| JPH04175254A (en) * | 1990-11-06 | 1992-06-23 | N M B:Kk | Cement dispersing agent preventing lowering of fluidity |
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