JP3578984B2 - Dispersant for hydraulic composition - Google Patents

Description

【００１１】
（式中、Ｒ_３、Ｒ_４は水素原子又はメチル基、ｍ_１は０〜２の数、ＡＯは炭素数２〜３のオキシアルキレン基、ｎ_２は２３以上１００未満の数、Ｘは水素原子又は炭素数１〜３のアルキル基を表す。）
【００１２】
【化４】

（式中、Ｒ、Ｒ’は水素原子又はメチル基、ｍ’は０〜２の数、Ａ’Ｏは炭素数２〜３のオキシアルキレン基、ｎ’は１００〜３００の数、Ｘ’は水素原子又は炭素数１〜３のアルキル基を表す。）
【化５】

【００１３】
（式中、Ｒ_５〜Ｒ_７は水素原子、メチル基又は（ＣＨ_２）_ｍ２ＣＯＯＭ_２、Ｒ_８は水素原子又はメチル基、Ｍ_１、Ｍ_２、Ｙは水素原子又は陽イオン、ｍ_２は０〜２の数を表す。）
【００１４】
【発明の実施の形態】
本発明の共重合体（イ）を構成するアルケニルエーテルの一般式（Ａ）に於いて、Ｒ₁ はアリル基である。ＡＯは、エチレンオキシド（以下ＥＯ）、プロピレンオキシド（以下ＰＯ）であり、付加形態は単独、ランダム、ブロック又は交互のいずれでもよい。好ましくはＥＯである。Ｒ₂は炭素数１〜３のアルキル基が好ましく、メチル、エチル、プロピル基等が挙げられる。特にメチル基が好ましい。
【００１５】
アルキレンオキシドの平均付加モル数ｎ_１は、１５〜９０の範囲であり、１５〜６０がより好ましく、２０〜５０が特に好ましい。この範囲内で物理的な攪拌力や温度による影響を受けにくく、安定した流動性を得ることができる。
【００１６】
本発明の共重合体（イ）は、これら一般式（Ａ）で表される単量体とマレイン酸との共重合体、好ましくはモル比が、一般式（Ａ）の単量体／マレイン酸＝３０／７０〜７０／３０である共重合体又はその塩である。マレイン酸は無水物であってもよい。かかる共重合体（イ）の製造方法としては、特開平２−１６３１０８号、特開平５−３４５６４７号記載の方法が挙げられる。
【００１７】
また、共重合体（イ）の好ましい重量平均分子量は流動性付与の点から、３０００〜３０万、更には５０００〜１０万である。
【００１８】
共重合体（イ）の一例として、マリアリムＥＫＭ、マリアリムＡＫＭ（日本油脂社製）やスーパー２００（電気化学社製）が挙げられる。
【００１９】
本発明の共重合体（ロ）は、炭素数２〜３のアルキレンオキシドを平均付加モル数で２３以上１００未満モル付加した一般式（Ｂ）で表される単量体（ａ）と前記一般式（Ｃ）及び／又は（Ｄ）、好ましくは一般式（Ｃ）で表される単量体（ｂ）とを含有する単量体混合物を重合してなる。前述した（イ）成分と併用した場合に安定した初期流動性を得るため、アルキレンオキシドの平均付加モル数ｎ₂は２３以上１００未満の範囲であり、２３以上９０以下が好ましく、２３以上７５以下がさらに好ましく、２３以上５０以下が最も好ましい。なお、共重合体（ロ）を得るための単量体混合物において、ｎ₂が異なる複数の単量体（ａ）を用いる場合は、全単量体（ａ）のｎ₂の平均値が２３以上１００未満の範囲にあるように組成を調整する。例えば、２種の単量体（ａ）を用いる場合、一方はｎ₂＝２３〜９６、他方はｎ₂’＝２３以上１００未満で、ｎ₂≠ｎ₂’かつｎ₂’≦ｎ₂＋３であることが好ましく、ｎ₂’≦ｎ₂＋５であることがより好ましく、ｎ₂’≦ｎ₂＋１０であることが最も好ましい。更に、本発明の効果を損なわない範囲で、単量体（ａ）としてｎ₂が１００以上の単量体を併用することもできる。
【００２０】
一般式（Ｂ）で表される単量体（ａ）としては、メトキシポリエチレングリコール、メトキシポリプロピレングリコール、エトキシポリエチレンポリプロピレングリコール等の片末端アルキル基封鎖ポリアルキレングリコールと（メタ）アクリル酸とのエステル化物や、（メタ）アクリル酸へのＥＯ、ＰＯ付加物が好ましく用いられる。付加形態は単独、ランダム、ブロック又は交互のいずれでもよい。より好ましくはメトキシポリエチレングリコールと（メタ）アクリル酸とのエステル化物であり、ＥＯ平均付加モル数が２以上１００未満のメトキシポリエチレングリコールとメタクリル酸とのエステル化物が特に好ましい。
【００２１】
一般式（Ｃ）で示される単量体としては、（メタ）アクリル酸、クロトン酸等の不飽和モノカルボン酸系単量体、無水マレイン酸、マレイン酸、無水イタコン酸、イタコン酸、フマル酸等の不飽和ジカルボン酸系単量体、又はこれらのアルカリ金属塩、アルカリ土類金属塩、アンモニウム塩、水酸基が置換されていてもよいモノ、ジ、トリアルキルアンモニウム塩が好ましく、より好ましくは（メタ）アクリル酸又はこれらのアルカリ金属塩である。
【００２２】
一般式（Ｄ）で示される単量体としては、アリルスルホン酸、メタリルスルホン酸、又はこれらのアルカリ金属塩、アルカリ土類金属塩、アンモニウム塩、水酸基が置換されていてもよいモノ、ジ、トリアルキルアンモニウム塩が使用される。
【００２３】
好ましくは、共重合体（ロ）は、前記一般式（Ｂ）で表される単量体（ａ）と、一般式（Ｃ）及び（Ｄ）で表される単量体の１種以上（ｂ）とを合わせて５０重量％以上、更には８０〜１００重量％以上、特には１００重量％含有する単量体混合物を重合して得られる。
【００２４】
共重合体（ロ）を構成する一般式（Ｂ）の単量体（ａ）と、一般式（Ｃ）及び／又は一般式（Ｄ）の単量体（ｂ）の反応単位は、（ａ）／（ｂ）＝１／１００〜５００／１００が流動性に優れ、好ましい。より好ましくは１／１００〜１００／１００、更に好ましくは１０／１００〜６０／１００、特に好ましくは１０／１００〜４０／１００である。
【００２５】
共重合体（ロ）の重量平均分子量は、流動性の点より５０００〜５０００００の範囲が良く、２００００〜１０００００、更に３００００〜８５０００の範囲が流動性に特に優れる。重量平均分子量はゲルパーミエーションクロマトグラフィ法（標準物質ポリスチレンスルホン酸ナトリウム換算）による。
【００２６】
共重合体（ロ）は公知の方法で製造できる。例えば、特開平７−２２３８５２号公報、特開平４−２０９７３７号公報、特開昭５８−７４５５２号公報の溶液重合法が挙げられ、水や炭素数１〜４の低級アルコール中、過硫酸アンモニウム、過酸化水素等の重合開始剤存在下、必要なら亜硫酸水素ナトリウムやメルカプトエタノール等を添加し、５０〜１００℃で０．５〜１０時間反応させればよい。
【００２７】
なお、共重合体（ロ）の原料として他の共重合可能なモノマーを併用でき、具体的には、アクリロニトリル、（メタ）アクリル酸アルキル（Ｃ_１〜Ｃ_１２）エステル、（メタ）アクリルアミド、スチレン、スチレンスルホン酸等が挙げられる。
【００２８】
本発明の共重合体（イ）と（ロ）の組成比は（イ）／（ロ）＝５〜９５／９５〜５（固形分重量比）が好ましく、１０〜９０／９０〜１０がより好ましく、２０〜８０／８０〜２０が特に好ましい。本発明の（イ）成分と（ロ）成分とを併用することで、コンクリートの練り上がり初期の流動性に関して、物理的な攪拌力や温度による影響を受けにくくなると推察され、極めて安定した流動性が得られる。
【００２９】
本発明のコンクリート混和剤は、共重合体（イ）と（ロ）の合計がセメントに対して固形分で０．０２〜１．０重量％、好ましくは０．１〜０．５重量％となるように添加される。
【００３０】
また本発明の共重合体（イ）と（ロ）はコンクリートに対し、予め両者を配合してから添加しても別々に添加してもよく、先に混練水で希釈してから用いてもよい。
【００３１】
本発明のコンクリート混和剤は、生コンクリートの製造の他、特に振動機や重力加速度３Ｇ〜６０Ｇの遠心力で締め固めて成型するコンクリート製品の製造に適する。更に、振動機を使用しない自己充填性の、５０ｃｍ（ＪＩＳ Ａ−１１０１スランプ試験に準ずるフロー値）以上の流動性を示す高流動性コンクリートにも用いることができる。
【００３２】
添加対象となるコンクリートはセメント、細骨材、粗骨材等を主成分とするものであるが、各種の高炉スラグ、フライアッシュ、珪砂、シリカフューム等を使用することができる。更に公知の添加剤（材）と併用することもでき、例えば、ＡＥ剤、ＡＥ減水剤、高性能減水剤、遅延剤、早強剤、促進剤、起泡剤、発泡剤、消泡剤、増粘剤、防水剤、防泡剤、高炉スラグ、フライアッシュ、等が挙げられる。これらを用いて調製された水硬性組成物のうち、本発明の分散剤は、水／水硬性粉体（特にセメント）重量比（Ｗ／Ｃ）が１０〜２５％、特に１５〜２５％の高強度水硬性組成物に特に好適である。
【００３３】
【実施例】
＜コンクリート配合＞
表１に示す配合条件によりコンクリートを調製した。
【００３４】
【表１】

【００３５】
Ｗ：水
Ｃ：シリカフュームセメント（密度：３．０８）
Ｓ：細骨材、君津産陸砂（密度：２．６１、ＦＭ：２．６４）
Ｇ：粗骨材、和歌山産砕石（密度：２．６３、ＦＭ：６．６４）
Ｗ／Ｃ＝（Ｗの単位重量／Ｃの単位重量）×１００（％）
ｓ／ａ＝〔細骨材容積／（細骨材容積＋粗骨材容積）〕×１００（％）。
【００３６】
＜性能評価＞
表２に示す共重合体（イ）と表３に示す共重合体（ロ）を、表４の組み合わせ、固形分重量比で配合してなる分散剤を、それぞれ表１のコンクリートに添加し、このコンクリートを５０Ｌ強制ミキサーで３０Ｌ練り、排出したフレッシュコンクリートについて、以下の測定を行った。結果を表４に示す。なお、表４中、実施例１〜７、１１、２０は比較例であるが、便宜的に実施例の欄に示してある。
【００３７】
（１）分散性
初期のスランプフロー（ＳＦ）値〔高流動コンクリート施工指針（コンクリートライブラリー９３）〕が、６５０〜７００ｍｍとなるのに要する分散剤の固形分量の総粉体に対する添加率を測定する。数値が小さい程、分散性が良い。
【００３８】
（２）分散保持性
排出３０分後のＳＦ値に対する初期ＳＦ値（上記分散性測定の際の初期ＳＦ値）の百分率を、分散保持性の尺度とする。数値が大きいほど分散保持性が良好とする。ただし、１００％を超える場合は、骨材分離する傾向にあるため、好ましくない。
【００３９】
（３）粘性
排出直後のフレッシュコンクリートから、目開き５ｍｍの篩で粗骨材を分離して得たモルタルを、ステンレス鋼（ＳＵＳ３０４）を加工して作製した図１の形状の装置に、下部排出開口を閉じた状態で充填し上部投入開口の面で擦り切った後、下部排出開口を開放してモルタルを自然流下させ、上部投入開口から目視で観察したときにモルタルの少なくとも一部に孔が確認されるまでの時間（流下時間）を測定し、これを粘性の評価に用いた。流下時間が過度に大きいと、充填時に多量の巻込み気泡や未充填部分が発生するので好ましくなく、流下時間が過度に小さいと、骨材分離抵抗性が低下して、未充填部分や水路が発生してやはり好ましくない。
【００４０】
【表２】

【００４１】
（注）ＡＯ及びｎ_１の欄の（ ）の次の数字がｎ_１である。また、共重合体（イ）のＮｏ．６のＥＯとＰＯはランダム付加である。Ｍｗは重量平均分子量である（以下同様）。
【００４２】
【表３】

【００４３】
（注）単量体（ａ）の種類の欄の（ ）の次の数字がｎ_２である。
【００４４】
【表４】

【００４５】
比較例２、４以外の比較例は、分散性が不十分なため、所定のＳＦ値を得るのに、多量の添加が必要となる。また、比較例１、２、５、６は、分散保持性が悪く、経時と共にＳＦ値が過度に増大し、骨材分離してしまうので好ましくない。更に、比較例４、６、８は、モルタル粘性が極めて高く、充填性に支障が生じる場合がある。比較例は全般に、Ｗ／Ｃがより低い系（配合Ｂ）で、粘性の増大が激しい傾向がある。
【００４６】
一方、実施例は何れも、Ｗ／Ｃの低い領域でも分散性、分散保持性及び粘性が安定していることがわかる。特に、共重合体（ロ）のＥＯ付加モル数ｎ_２が５０以下の場合に、モルタル粘性が低いので好ましい。また、分散性と粘性のバランスを考慮すると、共重合体（ロ）が三元共重合の場合がより好ましい。
【図面の簡単な説明】
【図１】実施例で流下時間の測定に用いた装置を示す概略図
【符号の説明】
１…上部投入開口
２…下部排出開口[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a dispersant for a hydraulic composition.
[0002]
[Prior art]
Concrete products, civil engineering, and building structures include products obtained by compacting concrete with an internal or external vibrator while pouring concrete into a formwork, and products obtained by centrifugal compaction such as piles, poles, and fume tubes. For these concrete products and high-strength structures, it is essential to add a high-performance water reducing agent in order to secure the strength.
[0003]
However, concrete to which a high-performance water reducing agent is added tends to vary in fluidity depending on the kneading time, and the filling of the concrete is reduced, resulting in insufficient compaction, the separation phenomenon resulting in reduced durability, and the appearance of the concrete surface. Causes damage.
[0004]
Further, a combination use of an alkenyl ether, a maleic anhydride copolymer, and a polycarboxylic acid-based dispersant for preventing a decrease in fluidity from immediately after kneading of concrete to about 60 minutes has been proposed (JP-A-5-345647). However, these are not very effective in stabilizing the fluidity at the very beginning until the concrete is kneaded.
[0005]
Furthermore, in the high-strength structure, in recent years, the hydraulic composition in the ultra-high-strength region of W / C [weight ratio calculated by water (W) / hydraulic powder (C) × 100] ≦ 30% has been developed. On the other hand, there is a demand for a dispersant which exhibits dispersibility and dispersion retention properties when added in an appropriate amount and has a small delay effect. For high-strength concrete applications, polycarboxylic acid-based dispersants (JP-A-8-12396) in which the number of moles of alkylene oxide added is specified to be from 50 to 100 have been proposed, but when W / C ≦ 30%, It is necessary to suppress the excessive viscosity of the concrete immediately after kneading and to stabilize the dispersion and maintenance until the concrete is filled.
[0006]
[Problems to be solved by the invention]
An object of the present invention is to provide a hydraulic composition dispersant capable of imparting stable fluidity to concrete and providing a stable concrete product or concrete structure regardless of fluctuations in the kneading time.
[0007]
In particular, it exhibits a dispersibility and a dispersion retention property by adding an appropriate amount to a hydraulic composition such as mortar or concrete in an ultra-high strength region of W / C ≦ 30%, has a small delay effect, and has a composition immediately after kneading. It is an object of the present invention to provide a dispersant capable of suppressing an excessive viscosity expression of a substance.
[0008]
[Means for Solving the Problems]
The present invention provides a dispersant for a high-strength hydraulic composition having a water / hydraulic powder weight ratio of 10 to 25%, comprising the following components (a) and (b) (provided that the following general formula: It contains a monomer (a ′) represented by (B ′) and one or more monomers (b) selected from compounds represented by the following general formulas (C) and (D). A high-strength hydraulic composition having a water / hydraulic powder weight ratio of 10 to 25%, which contains a copolymer obtained by polymerizing a monomer mixture) and the dispersant ; Also, the present invention relates to a method for producing a high-strength hydraulic composition having a water / hydraulic powder weight ratio of 10 to 25% using the dispersant .
(A) Component: A copolymer of allyl ether and maleic acid represented by the following general formula (A) or a salt thereof.
[0009]
R ₁ O (AO) _n1 R ₂ (A)
(In the formula, R ₁ represents an allyl group , AO represents an oxyalkylene group having 2 to 3 carbon atoms, n ₁ represents a number of 15 to 90, and R ₂ represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms.)
(B) Component: at least one monomer selected from the monomers (a) represented by the following general formula (B) and the compounds represented by the following general formulas (C) and (D) (B) is a copolymer obtained by polymerizing a monomer mixture containing (a) and (b), wherein the reaction units of the monomers (a) and (b) constituting the copolymer are (a) / (B) = 1/100 to 60/100 copolymer .
[0010]
Embedded image

[0011]
(Wherein, R ₃ and R ₄ are hydrogen atoms or methyl groups, m ₁ is a number of 0 to 2, AO is an oxyalkylene group having 2 to 3 carbon atoms, n ₂ is a number of 23 or more and less than 100, X is hydrogen Represents an atom or an alkyl group having 1 to 3 carbon atoms.)
[0012]
Embedded image

(Wherein R and R ′ are a hydrogen atom or a methyl group, m ′ is a number of 0 to 2, A′O is an oxyalkylene group having 2 to 3 carbon atoms, n ′ is a number of 100 to 300, and X ′ is Represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms.)
Embedded image

[0013]
(Wherein, R _{5 to} R ₇ are a hydrogen atom, a methyl group or (CH ₂ ) _m2 COOM ₂ , R ₈ is a hydrogen atom or a methyl group, M ₁ , M ₂ , Y is a hydrogen atom or a cation, and m ₂ is Represents the number of 0 to 2)
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
In the general formula (A) of the alkenyl ether constituting the copolymer (a) of the present invention, R ₁ is an allyl group. AO is ethylene oxide (hereinafter referred to as EO) or propylene oxide (hereinafter referred to as PO), and the addition form may be any of single, random, block or alternating. Preferably, it is EO. R ₂ is preferably an alkyl group having 1 to 3 carbon atoms, and examples thereof include a methyl, ethyl and propyl group. Particularly, a methyl group is preferable.
[0015]
The average addition mole number _{n 1} of the alkylene oxide is in the range of 15 to 90, more preferably from 15 to 60, particularly preferably 20 to 50. Within this range, it is hardly affected by physical stirring power and temperature, and stable fluidity can be obtained.
[0016]
The copolymer (a) of the present invention is a copolymer of the monomer represented by the general formula (A) and maleic acid, preferably, the monomer / maleic of the general formula (A) having a molar ratio of It is a copolymer having an acid of 30/70 to 70/30 or a salt thereof. Maleic acid may be an anhydride. Examples of the method for producing such a copolymer (a) include the methods described in JP-A-2-163108 and JP-A-5-345647.
[0017]
The preferred weight average molecular weight of the copolymer (a) is 3000 to 300,000, and more preferably 5000 to 100,000 from the viewpoint of imparting fluidity.
[0018]
Examples of the copolymer (a) include Marialim EKM, Marialim AKM (manufactured by NOF Corporation) and Super 200 (manufactured by Denki Kagaku).
[0019]
The copolymer (b) of the present invention comprises a monomer (a) represented by the general formula (B) in which an alkylene oxide having 2 to 3 carbon atoms is added in an amount of 23 or more and less than 100 in terms of an average addition mole number, and It is obtained by polymerizing a monomer mixture containing the monomer (b) represented by the formula (C) and / or (D), preferably the general formula (C). To obtain a stable initial fluidity when used in combination with the above-mentioned component (i), the average addition molar number n ₂ of the alkylene oxide is in the range of less than 23 or more 100 preferably 23 or more and 90 or less, 23 or more 75 or less Is more preferable, and 23 or more and 50 or less are most preferable. When a plurality of monomers (a) having different n ₂ are used in the monomer mixture for obtaining the copolymer (b), the average value of n ₂ of all the monomers (a) is 23. The composition is adjusted so as to be in the range of at least 100 and less than 100. For example, when two kinds of monomers (a) are used, one is n ₂ = 23 to 96, the other is n ₂ ′ = 23 or more and less than 100, and n ₂ ≠ n ₂ ′ and n ₂ ′ ≦ n ₂ +3 Is preferable, n ₂ ′ ≦ n ₂ +5 is more preferable, and n ₂ ′ ≦ n ₂ +10 is most preferable. Further, as long as the effects of the present invention are not impaired, a monomer having n ₂ of 100 or more can be used in combination as the monomer (a).
[0020]
Examples of the monomer (a) represented by the general formula (B) include an esterified product of (meth) acrylic acid with a polyalkylene glycol having an alkyl group at one end, such as methoxypolyethylene glycol, methoxypolypropylene glycol, or ethoxypolyethylene polypropylene glycol. Alternatively, an EO or PO adduct to (meth) acrylic acid is preferably used. The additional form may be single, random, block or alternating. More preferably, it is an esterified product of methoxypolyethylene glycol and (meth) acrylic acid, and particularly preferably an esterified product of methoxypolyethylene glycol and methacrylic acid having an average addition mole number of EO of 2 or more and less than 100.
[0021]
Examples of the monomer represented by the general formula (C) include unsaturated monocarboxylic acid monomers such as (meth) acrylic acid and crotonic acid, maleic anhydride, maleic acid, itaconic anhydride, itaconic acid, and fumaric acid. And the like, or an alkali metal salt, an alkaline earth metal salt, an ammonium salt, and a mono-, di-, or trialkylammonium salt which may have a substituted hydroxyl group, and more preferably ( (Meth) acrylic acid or alkali metal salts thereof.
[0022]
Examples of the monomer represented by the general formula (D) include allyl sulfonic acid, methallyl sulfonic acid, or an alkali metal salt, an alkaline earth metal salt, an ammonium salt, and a mono- or di-substituted hydroxyl group thereof. , Trialkylammonium salts are used.
[0023]
Preferably, the copolymer (b) comprises one or more monomers (a) represented by the general formula (B) and one or more monomers represented by the general formulas (C) and (D) ( b) is obtained by polymerizing a monomer mixture containing at least 50% by weight, more preferably at least 80 to 100% by weight, especially 100% by weight.
[0024]
The reaction unit of the monomer (a) of the general formula (B) constituting the copolymer (b) and the monomer (b) of the general formula (C) and / or the general formula (D) is (a) ) / (B) = 1 / 100-500 / 100 is excellent in fluidity and is preferred. The ratio is more preferably 1/100 to 100/100, further preferably 10/100 to 60/100, and particularly preferably 10/100 to 40/100.
[0025]
The weight average molecular weight of the copolymer (b) is preferably in the range of 5,000 to 500,000 from the viewpoint of fluidity, and in the range of 20,000 to 100,000, and more preferably 30,000 to 85,000, and the fluidity is particularly excellent. The weight average molecular weight is determined by gel permeation chromatography (standard substance: sodium polystyrene sulfonate).
[0026]
The copolymer (b) can be produced by a known method. For example, the solution polymerization method described in JP-A-7-223852, JP-A-4-209737, and JP-A-58-74552 may be mentioned. In water or a lower alcohol having 1 to 4 carbon atoms, ammonium persulfate, In the presence of a polymerization initiator such as hydrogen oxide, if necessary, sodium bisulfite, mercaptoethanol, or the like may be added, and the reaction may be performed at 50 to 100 ° C. for 0.5 to 10 hours.
[0027]
In addition, other copolymerizable monomers can be used in combination as a raw material of the copolymer (b). Specifically, acrylonitrile, alkyl (meth) acrylate (C ₁ -C ₁₂ ) ester, (meth) acrylamide, styrene And styrene sulfonic acid.
[0028]
The composition ratio of the copolymers (a) and (b) of the present invention is preferably (a) / (b) = 5-95 / 95-5 (solid content weight ratio), more preferably 10-90 / 90-10. Preferably, 20-80 / 80-20 are especially preferable. It is presumed that the combined use of the component (a) and the component (b) of the present invention makes it difficult for the fluidity in the initial stage of kneading of the concrete to be affected by the physical stirring force and the temperature. Is obtained.
[0029]
In the concrete admixture of the present invention, the total amount of the copolymers (a) and (b) is 0.02 to 1.0% by weight, preferably 0.1 to 0.5% by weight, based on the cement. To be added.
[0030]
Further, the copolymers (a) and (b) of the present invention may be added to concrete in advance after blending both or may be added separately, or may be used after previously diluted with kneading water. Good.
[0031]
The concrete admixture of the present invention is suitable not only for production of ready-mixed concrete but also for production of concrete products which are compacted and compacted by a vibrator or a centrifugal force having a gravitational acceleration of 3G to 60G. Furthermore, it can be used for a highly fluid concrete having a fluidity of 50 cm (flow value according to JIS A-1101 slump test) or more, which is self-filling without using a vibrator.
[0032]
The concrete to be added is mainly composed of cement, fine aggregate, coarse aggregate and the like, and various blast furnace slag, fly ash, silica sand, silica fume and the like can be used. Further, it can be used in combination with known additives (materials), for example, an AE agent, an AE water reducing agent, a high-performance water reducing agent, a retarding agent, a quick strengthening agent, an accelerator, a foaming agent, a foaming agent, a defoaming agent, Examples include thickeners, waterproofing agents, antifoaming agents, blast furnace slag, fly ash, and the like. Among the hydraulic compositions prepared using these, the dispersant of the present invention has a water / hydraulic powder (particularly cement) weight ratio (W / C) of 10 to 25%, particularly 15 to 25%. It is particularly suitable for high-strength hydraulic compositions.
[0033]
【Example】
<Concrete mix>
Concrete was prepared under the mixing conditions shown in Table 1.
[0034]
[Table 1]

[0035]
W: Water C: Silica fume cement (density: 3.08)
S: Fine aggregate, land sand from Kimitsu (density: 2.61, FM: 2.64)
G: Coarse aggregate, crushed stone from Wakayama (density: 2.63, FM: 6.64)
W / C = (unit weight of W / unit weight of C) × 100 (%)
s / a = [fine aggregate volume / (fine aggregate volume + coarse aggregate volume)] × 100 (%).
[0036]
<Performance evaluation>
The copolymer (a) shown in Table 2 and the copolymer (b) shown in Table 3 were added to the concrete shown in Table 1 in combination with the combination shown in Table 4 at a solid content weight ratio. 30 L of this concrete was kneaded with a 50 L forced mixer, and the following measurement was performed on the discharged fresh concrete. Table 4 shows the results. In Table 4, Examples 1 to 7, 11, and 20 are comparative examples, but are shown in the column of Examples for convenience.
[0037]
(1) Dispersibility The slump flow (SF) value at the initial stage [High fluidity concrete construction guideline (concrete library 93)] measures the addition ratio of the solid content of the dispersant to the total powder required to reach 650 to 700 mm. I do. The smaller the value, the better the dispersibility.
[0038]
(2) Dispersion retention The percentage of the initial SF value (the initial SF value at the time of the dispersibility measurement) with respect to the SF value 30 minutes after discharge was used as a measure of dispersion retention. The larger the value, the better the dispersion retention. However, if it exceeds 100%, the aggregate tends to separate, which is not preferable.
[0039]
(3) A mortar obtained by separating coarse aggregate from a fresh concrete immediately after viscous discharge with a sieve having an opening of 5 mm and processing the stainless steel (SUS304) into a device having a shape shown in FIG. After filling with the opening closed and scraping off at the surface of the upper input opening, the lower discharge opening is opened to allow the mortar to flow naturally, and holes are formed in at least a part of the mortar when visually observed from the upper input opening. The time until it was confirmed (flow time) was measured and used for the evaluation of viscosity. If the flowing time is excessively large, a large amount of entrapped air bubbles and unfilled portions are generated at the time of filling. It is still undesirable because it occurs.
[0040]
[Table 2]

[0041]
The following numbers are _{n 1} of Note in column AO and _{n 1} (). Further, the copolymer (a) No. EO and PO of 6 are random additions. Mw is a weight average molecular weight (the same applies hereinafter).
[0042]
[Table 3]

[0043]
(Note) The following numbers of the monomer of the type of column (a) () is _{n 2.}
[0044]
[Table 4]

[0045]
Comparative Examples other than Comparative Examples 2 and 4 have insufficient dispersibility, so that a large amount of addition is required to obtain a predetermined SF value. Further, Comparative Examples 1, 2, 5, and 6 are not preferable because the dispersion retention is poor, the SF value excessively increases with time, and aggregates are separated. Further, Comparative Examples 4, 6, and 8 have extremely high mortar viscosity, which may cause a problem in the filling property. Comparative examples generally have a lower W / C (formulation B) and tend to have a sharp increase in viscosity.
[0046]
On the other hand, in each of the examples, it can be seen that the dispersibility, the dispersion retention, and the viscosity are stable even in the low W / C region. In particular, when the EO addition molar number n ₂ of the copolymer (B) is 50 or less, because of the low mortar viscosity preferred. Further, in consideration of the balance between the dispersibility and the viscosity, it is more preferable that the copolymer (b) is a terpolymer.
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing an apparatus used for measuring a flow time in an embodiment.
1 Upper opening 2 Lower outlet

Claims (5)

A dispersant for a high-strength hydraulic composition having a water / hydraulic powder weight ratio of 10 to 25%, comprising the following components (a) and (b) (however, the following general formula (B ′) A monomer mixture containing a monomer (a ′) represented by the following formula and one or more monomers (b) selected from compounds represented by the following general formulas (C) and (D) Excluding those containing a copolymer obtained by polymerizing
(A) Component: A copolymer of allyl ether and maleic acid represented by the following general formula (A) or a salt thereof.
R ₁ O (AO) _n1 R ₂ (A)
(In the formula, R ₁ represents an allyl group, AO represents an oxyalkylene group having 2 to 3 carbon atoms, n ₁ represents a number of 15 to 90, and R ₂ represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms.)
(B) Component: at least one monomer selected from the monomers (a) represented by the following general formula (B) and the compounds represented by the following general formulas (C) and (D) (B) is a copolymer obtained by polymerizing a monomer mixture containing (a) and (b), wherein the reaction units of the monomers (a) and (b) constituting the copolymer are (a) / (B) = 1/100 to 60/100 copolymer.

(Wherein, R ₃ and R ₄ are hydrogen atoms or methyl groups, m ₁ is a number of 0 to 2, AO is an oxyalkylene group having 2 to 3 carbon atoms, n ₂ is a number of 23 or more and less than 100, X is hydrogen Represents an atom or an alkyl group having 1 to 3 carbon atoms.)

(Wherein R and R ′ are a hydrogen atom or a methyl group, m ′ is a number of 0 to 2, A′O is an oxyalkylene group having 2 to 3 carbon atoms, n ′ is a number of 100 to 300, and X ′ is Represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms.)

(Wherein, R _{5 to} R ₇ are a hydrogen atom, a methyl group or (CH ₂ ) _m2 COOM ₂ , R ₈ is a hydrogen atom or a methyl group, M ₁ , M ₂ , Y is a hydrogen atom or a cation, and m ₂ is Represents the number of 0 to 2) The dispersant for a hydraulic composition according to claim 1, wherein the solid content weight ratio of the component (a) and the component (b) is (a) / (b) = 5 to 95/95 to 5. The dispersant for a hydraulic composition according to claim 1 or 2, wherein the reaction unit of the allyl ether and maleic acid constituting the copolymer (a) is 30/70 to 70/30. A high-strength hydraulic composition having a water / hydraulic powder weight ratio of 10 to 25%, comprising the hydraulic composition dispersant according to any one of claims 1 to 3 . A method for producing a high-strength hydraulic composition having a water / hydraulic powder weight ratio of 10 to 25% using the hydraulic composition dispersant according to any one of claims 1 to 3 .

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