JPS6158082B2 - - Google Patents
Info
- Publication number
- JPS6158082B2 JPS6158082B2 JP54112908A JP11290879A JPS6158082B2 JP S6158082 B2 JPS6158082 B2 JP S6158082B2 JP 54112908 A JP54112908 A JP 54112908A JP 11290879 A JP11290879 A JP 11290879A JP S6158082 B2 JPS6158082 B2 JP S6158082B2
- Authority
- JP
- Japan
- Prior art keywords
- condensation
- reaction
- formaldehyde
- melamine
- molar ratio
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- WSFSSNUMVMOOMR-UHFFFAOYSA-N Formaldehyde Chemical compound O=C WSFSSNUMVMOOMR-UHFFFAOYSA-N 0.000 claims description 34
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 22
- 238000006482 condensation reaction Methods 0.000 claims description 17
- 229920000877 Melamine resin Polymers 0.000 claims description 16
- 239000007859 condensation product Substances 0.000 claims description 16
- 239000003638 chemical reducing agent Substances 0.000 claims description 13
- 238000009833 condensation Methods 0.000 claims description 10
- 230000005494 condensation Effects 0.000 claims description 10
- JDSHMPZPIAZGSV-UHFFFAOYSA-N melamine Chemical compound NC1=NC(N)=NC(N)=N1 JDSHMPZPIAZGSV-UHFFFAOYSA-N 0.000 claims description 10
- 239000007787 solid Substances 0.000 claims description 10
- 229910052783 alkali metal Inorganic materials 0.000 claims description 9
- -1 alkali metal sulfite Chemical class 0.000 claims description 9
- 238000004519 manufacturing process Methods 0.000 claims description 7
- 125000000542 sulfonic acid group Chemical group 0.000 claims description 7
- IVJISJACKSSFGE-UHFFFAOYSA-N formaldehyde;1,3,5-triazine-2,4,6-triamine Chemical compound O=C.NC1=NC(N)=NC(N)=N1 IVJISJACKSSFGE-UHFFFAOYSA-N 0.000 claims description 6
- 239000002253 acid Substances 0.000 claims description 5
- MBHRHUJRKGNOKX-UHFFFAOYSA-N [(4,6-diamino-1,3,5-triazin-2-yl)amino]methanol Chemical compound NC1=NC(N)=NC(NCO)=N1 MBHRHUJRKGNOKX-UHFFFAOYSA-N 0.000 claims description 4
- 229910052500 inorganic mineral Inorganic materials 0.000 claims description 4
- 239000011707 mineral Substances 0.000 claims description 4
- 239000002585 base Substances 0.000 claims description 3
- 239000007788 liquid Substances 0.000 claims description 3
- 239000007864 aqueous solution Substances 0.000 claims description 2
- 238000010438 heat treatment Methods 0.000 claims description 2
- LSNNMFCWUKXFEE-UHFFFAOYSA-L sulfite Chemical class [O-]S([O-])=O LSNNMFCWUKXFEE-UHFFFAOYSA-L 0.000 claims 1
- 238000006243 chemical reaction Methods 0.000 description 21
- 238000000034 method Methods 0.000 description 18
- 239000004568 cement Substances 0.000 description 16
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 15
- 239000006227 byproduct Substances 0.000 description 12
- LSNNMFCWUKXFEE-UHFFFAOYSA-N Sulfurous acid Chemical compound OS(O)=O LSNNMFCWUKXFEE-UHFFFAOYSA-N 0.000 description 10
- 239000000047 product Substances 0.000 description 8
- 230000000052 comparative effect Effects 0.000 description 7
- 230000000694 effects Effects 0.000 description 7
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 6
- 239000004570 mortar (masonry) Substances 0.000 description 5
- 150000003839 salts Chemical class 0.000 description 5
- HRZFUMHJMZEROT-UHFFFAOYSA-L sodium disulfite Chemical compound [Na+].[Na+].[O-]S(=O)S([O-])(=O)=O HRZFUMHJMZEROT-UHFFFAOYSA-L 0.000 description 5
- 235000010262 sodium metabisulphite Nutrition 0.000 description 5
- PMZURENOXWZQFD-UHFFFAOYSA-L Sodium Sulfate Chemical compound [Na+].[Na+].[O-]S([O-])(=O)=O PMZURENOXWZQFD-UHFFFAOYSA-L 0.000 description 4
- 230000035484 reaction time Effects 0.000 description 4
- 230000001603 reducing effect Effects 0.000 description 4
- 229910052938 sodium sulfate Inorganic materials 0.000 description 4
- 235000011152 sodium sulphate Nutrition 0.000 description 4
- 239000000243 solution Substances 0.000 description 4
- 238000006277 sulfonation reaction Methods 0.000 description 4
- 230000007423 decrease Effects 0.000 description 3
- 239000004576 sand Substances 0.000 description 3
- 230000002411 adverse Effects 0.000 description 2
- 229910010272 inorganic material Inorganic materials 0.000 description 2
- 239000011147 inorganic material Substances 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 239000000843 powder Substances 0.000 description 2
- 239000002244 precipitate Substances 0.000 description 2
- 238000000746 purification Methods 0.000 description 2
- 229920005989 resin Polymers 0.000 description 2
- 239000011347 resin Substances 0.000 description 2
- 239000011734 sodium Substances 0.000 description 2
- 239000011343 solid material Substances 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 229910019142 PO4 Inorganic materials 0.000 description 1
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 description 1
- 230000002378 acidificating effect Effects 0.000 description 1
- 239000004480 active ingredient Substances 0.000 description 1
- 239000003513 alkali Substances 0.000 description 1
- 150000001340 alkali metals Chemical class 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 239000012141 concentrate Substances 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 238000001879 gelation Methods 0.000 description 1
- 229910052602 gypsum Inorganic materials 0.000 description 1
- 239000010440 gypsum Substances 0.000 description 1
- 150000003840 hydrochlorides Chemical class 0.000 description 1
- 239000012263 liquid product Substances 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- WSFSSNUMVMOOMR-NJFSPNSNSA-N methanone Chemical compound O=[14CH2] WSFSSNUMVMOOMR-NJFSPNSNSA-N 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 230000007935 neutral effect Effects 0.000 description 1
- 150000002823 nitrates Chemical class 0.000 description 1
- 231100000989 no adverse effect Toxicity 0.000 description 1
- 235000021317 phosphate Nutrition 0.000 description 1
- 150000003013 phosphoric acid derivatives Chemical class 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 238000010992 reflux Methods 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 238000007086 side reaction Methods 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
- 125000001174 sulfone group Chemical group 0.000 description 1
- 239000008030 superplasticizer Substances 0.000 description 1
- 230000008719 thickening Effects 0.000 description 1
Description
本発明は減水剤として使用されるスルホン酸基
を有するメラミンホルムアルデヒド縮合生成物の
製法に係るものである。
スルホン酸基を有するメラミンホルムアルデヒ
ド縮合生成物の製法及び該生成物が減水剤として
有効であることが特公昭43−21659号公報及び特
公昭52−13991号公報に報ぜられている。該公報
に提案されている縮合生成物はメラミン、ホルム
アルデヒド、スルホン酸基のモル比が１：３：１
の縮合生成物であり、モルタルの減水性能はかな
り優れているが、モルタル調製後早期に圧縮強度
が向上しない欠点がある。また該方法によるとき
は、硫酸ナトリウム等の中性塩の副生が多く、縮
合生成物をそのまま、又は水分を蒸発除去して使
用するときは、これら副生物を固形物中に15〜30
％含むので有効成分量が少くなり、また、モルタ
ル性能に悪影響を及ぼすこととなり、これら副生
物を除去するには別精製工程を別に付加しなけ
ればならない。
本発明の目的は、セメント、石こう等の水硬性
無機材料の混水量を減少することができ、しかも
セメント硬化体に強度を向上する減水剤及びその
製法を提供するにある。
本発明の他の目的は、副生物の生成が少く、縮
合反応を迅速に行わしめることができる減水剤と
してのスルホン酸基を有するメラミンホルムアル
デヒド縮合生成物の製法を提供するにある。
本発明による高性能減水剤としてのスルホン酸
基を有するメラミンホルムアルデヒド縮合生成物
の製法は、メラミン、ホルムアルデヒド及びアル
カリ金属亜硫酸塩を１：2.7〜3.2：0.3〜0.7のモ
ル比で、又は前述のモル比でメラミンとホルムア
ルデヒドを先に反応せしめて得られたメチロール
メラミン及びアルカリ金属亜硫酸塩を、PH10〜13
の塩基性水溶液中で亜硫酸塩が検出されなくなる
まで60〜80℃の温度で加熱した後鉱酸を加えてPH
を５〜７に調整して、30〜70℃の温度に加熱し、
縮合生成液がPH7.5〜11.0に調整され20℃で固形
物濃度が20重量％のときの粘度が５〜40cpにな
るまで、縮合した後、塩基を加えてPHを7.5〜
11.0として縮合反応を停止せしめることを特徴と
する方法である。
本発明の方法の一つの大きな特徴は、本発明の
方法により得られるメラミン、ホルムアルデヒド
及びスルホン酸基のモル比が１：2.7〜3.2：0.3〜
0.7、即ち概ね１：３：0.5のスルホン基を有する
メラミンホルムアルデヒドの特定の縮合物がこれ
をセメントに混和した際すぐれた減水性を有する
と共に、セメント硬化体の強度を著しく向上する
ことである。
本発明の方法の他の大きな特徴は、特に縮合反
応をPH値の高い領域において行い、反応速度を低
下することなく副生物の生成をすくなくすること
ができ過精製を行うことなく、そのまま又は水
分を蒸発せしめて固形物として使用して優れた効
果をあげることができ、且つ縮合反応時間が短い
ことである。
本発明の方法の其他の特徴は、以下の記載より
理解されるであろう。
本発明の方法においては先ず、メラミン
（Ｍ）、ホルムアルデヒド（Ｆ）及びアルカリ金属
亜硫酸塩（Ｓ）を１：2.7〜3.2：0.3〜0.7のモル
比で、又は前述のモル比でメラミン（Ｍ）とホル
ムアルデヒド（Ｆ）を先に反応せしめて得られた
メチロールメラミン及びアルカリ金属亜硫酸塩
（Ｓ）を、PH10〜13の塩基性水溶液中で60〜80℃
の温度で加熱する。これを第１反応という。メラ
ミンとホルムアルデヒドを先に反応せしめてメチ
ロールメラミンとした後、これとアルカリ金属亜
硫酸塩と反応せしめる方法はＭ，Ｆ，Ｓを直接混
合して反応せしめる方法に較べて副反応が少いの
で好ましい。
第１反応において、Ｆ／Ｍモル比＜2.7では水
溶性が不良となり、縮合反応時に析出物を生じ増
粘する。またＦ／Ｍモル比＞3.2では縮合反応時
にゲル化し易く、安定して貯蔵し得る水溶性樹脂
が得られない。
第１反応において、Ｓ／Ｍモル比＜0.3では、
縮合反応時に樹脂が白濁析出する。またＳ／Ｍモ
ル比＞0.7とすると、次の縮合反応においてPH５
〜７の条件では反応時間が長くなり、PHを５以下
に下げれば反応時間は短縮できるが、副生塩が増
大し、分離精製工程を要することとなる。
第１反応における反応温度を60℃以下とすると
反応時間を多く要し、80℃以上とすると硫酸塩の
副生が多くなりスルホン化率が低下する。
また、PHを10以下とするとスルホン化が充分進
行しなく、13以上ではスルホン化を早める効果は
なく徒にアルカリ消費量を増加するのみで、次の
縮合反応の為の酸の消費量が増加し、副生塩が増
加することとなる。
第１反応は亜硫酸塩が検出されなくなるまで行
われる。第１反応終了後、縮合反応を進めるため
の第２反応が行われる。即ち、鉱酸を加えてPHを
５〜７に調整して、30〜70℃の温度に加熱して縮
合せしめる。
第２反応において、PH＜５とすると副生塩の量
が増加し、PH＞７とすると縮合反応が遅く時間を
多く要す。また30℃以下では長時間要し、70℃以
上とするとスルホン基の離脱が起り、スルホン化
率が低下する。
第２反応は、NaOH又はCa（OH）2等の塩基を
加えPHを7.5〜11.0とすることにより停止する。
第２反応の終点はPHを7.5〜11.0に調整し、20℃
で固形物濃度が20重量％のときの粘度が５〜
40cp、好ましくは７〜20cp、となる範囲とされ
る。この範囲外の粘度になるような縮合物は、減
水効果及びセメント硬化体の強度向上効果が少な
い。
本発明の方法に用いられるアルカリ金属亜硫酸
塩としては亜硫酸基（SO3 -2）、ピロ亜硫酸基
（S2O5 -2）酸性亜硫酸基（HSO3 -1）等とアルカリ金
属、主としてNa又はＫ等の塩が用いられる。
第１反応のPH調整剤には無機及び有機のアルカ
リが用いられるが、水酸化ナトリウム等の無機の
アルカリの方が好ましい。第２反応において加え
られる鉱酸としては、塩酸塩、硝酸塩、燐酸塩等
は製品中に残存するとセメント等に悪影響を及ぼ
すので硫酸が好ましい。
本発明の方法により目的とする縮合生成物の20
〜50重量％の溶液が得られる。固形物中の副生物
の硫酸ナトリウム等の含有率は２〜３重量％以下
で少ない。従つて、そのまま、又は必要に応じて
濃縮し、実用に供することができる。このもの、
又は濃縮物は、ポツトライフが長く、貯蔵安定性
も高い。乾燥して粉状品とすることもできる。減
水剤は通常、水に溶解して、セメントに対して通
常数％以下、概ね0.1〜２％の添加率で使用され
るが、製造者より使用者への供給は液状品が都合
がよい。特に、セメントに対する使用比率が少な
いので、粉状品の純度は重要である。本発明によ
る減水剤は純度が高いので、その使用面から、水
添加量の設計、硬化物の強度設計等において、極
めて有利である。
以上の如く、本発明の方法により得られる減水
剤は、すぐれた減水効果をあげると共に、セメン
ト硬化体の強度を向上することができ、低温での
硬化にも極めて有用である。また、副生物の含有
量が少ないので、水硬性無機材料硬化物に悪影響
を及ぼすことがなく、取扱い、使用に便である。
更に本発明の方法は副生物の生成が少なく、上述
の如き優れた減水剤を得ることができると共に、
所要時間、原料、工程が少なくすむので効率的な
低コストの方法である。
次に実施例を述べる。
実施例 １
還流冷却器、撹拌装置、温度計のついた１の
４つ口フラスコにメラミン126.0ｇ（１ｇモル）、
40％ホルマリン225ｇ（ホルムアルデヒド３ｇモ
ル）を入れ、PH7.5、温度70℃にて反応させ、反
応液が透明になつたところで速やかに50℃に冷却
し、ピロ亜硫酸ナトリウムNa2S2O547.5ｇ（0.25
ｇモル、亜硫酸塩として0.5ｇモルに相当）、水
730ｇ、及び水酸化ナトリウムを加えPHを11.0と
し、60℃の温度で亜硫酸塩が検出されなくなるま
で、約１時間反応した。
次に反応液を５％硫酸でPH6.0に下げて温度60
℃で縮合せしめた。縮合反応は約１時間〜１時間
30分（繰返し実験における差。）要し、20％水酸
化ナトリウムで中和してPHを約９として20℃に冷
却し、粘度が7CPになつた点で縮合を中止し、上
述の如く中和冷却して、縮合生成物を得た。縮合
生成物の固形物濃度は20重量％、固形物中の硫酸
ナトリウム含有量は３重量％であつた。
この方法によつて得られた縮合生成液減水剤を
モルタルに添加し、JIS Ｒ 5201に示された方法
によりフロー値及び圧縮強度を測定した。
実験条件は次の通りである。
セメント：ポルドランドセメント（秩父セメント
製）
砂 ：豊浦産標準砂
混合割合：セメント／水／砂＝600/300/1200（重
量部）
水セメント比（Ｗ／Ｃ）：0.55
養生条件：23℃
試験結果は比較例と共に第１表に示す。
比較例 １
ピロ亜硫酸ナトリウムを19ｇ（0.1ｇモル亜硫
酸塩として0.2ｇモル）としたほか、実施例１と
同様に反応を行つた。但し縮合反応において約30
分で自濁物が生成し、爾後の反応が不可能となつ
た。
比較例 ２
ピロ亜硫酸ナトリウムを95ｇ（0.5ｇモル、亜
硫酸塩として１ｇモル）とせるほか、実施例１と
同様に反応した。但し、縮合反応を16時間以上行
つても縮合は進まず、固形物濃度20重量％、20℃
における粘度2cpの点で縮合を終了とした。
比較例 ３
ピロ亜硫酸ナトリウムを76ｇ（0.4ｇモル、亜
硫酸塩として0.8ｇモル）とせるほか、実施例１
と同様に反応した。但し、縮合反応を10時間以上
行つても縮合は進まず、固形物濃度20重量％20℃
における粘度2.5cpの点で縮合を終了とした。
比較例 ４
実施例１と同様にメラミン88.2ｇ（0.7ｇモ
ル）、37％ホルマリン170.3ｇ（ホルムアルデヒド
2.1ｇモル）及びピロ亜硫酸ナトリウム70ｇ
（0.37ｇモル、亜硫酸塩として0.74ｇモル）を使
用して第１反応を行つた。縮合反応をPHを4.0と
して行つた。これに要した50％硫酸は350ｇであ
り、実施例１の場合の約６倍の量であつた。縮合
には約２時間要した。縮合後20％水酸化ナトリウ
ムで中和し、PH9.0として冷却し、20℃で固形物
21.2％、粘度8CPの縮合水溶液が得られた。この
生成物の固形物中には約20％の硫酸ナトリウムが
含まれていた。
実施例１、比較例２及び比較例３の縮合生成物
を固形物としてセメントに対して0.5重量％モル
タルに添加して前述の条件にて測定したフロー値
及び圧縮強度を無添加のもの及び市販の同系統の
減水剤（Ｓ／Ｍモル比１、Ｆ／Ｍモル比３）添加
のもの（添加量同じ）と共に第１表に示す。
The present invention relates to a method for producing a melamine formaldehyde condensation product having sulfonic acid groups for use as a water reducing agent. A method for producing a melamine formaldehyde condensation product having a sulfonic acid group and the effectiveness of the product as a water reducing agent are reported in Japanese Patent Publications No. 43-21659 and No. 52-13991. The condensation product proposed in the publication has a molar ratio of melamine, formaldehyde, and sulfonic acid groups of 1:3:1.
Although it is a condensation product of mortar and has quite excellent water reduction performance, it has the disadvantage that compressive strength does not improve early after mortar preparation. In addition, when this method is used, there are many by-products of neutral salts such as sodium sulfate, and when the condensation product is used as it is or after the water is removed by evaporation, these by-products are added to the solid material at a concentration of 15 to 30%.
%, the amount of active ingredients decreases and also has an adverse effect on mortar performance, and a separate purification step must be added to remove these by-products. An object of the present invention is to provide a water reducing agent that can reduce the amount of water mixed with hydraulic inorganic materials such as cement and gypsum, and also improve the strength of hardened cement products, and a method for producing the same. Another object of the present invention is to provide a method for producing a melamine-formaldehyde condensation product having a sulfonic acid group as a water-reducing agent, by which the condensation reaction can be carried out rapidly and with little generation of by-products. The method for producing the melamine-formaldehyde condensation product having sulfonic acid groups as a superplasticizer according to the present invention comprises combining melamine, formaldehyde and an alkali metal sulfite in a molar ratio of 1:2.7 to 3.2:0.3 to 0.7 or the above-mentioned molar ratio. Methylolmelamine and alkali metal sulfite obtained by first reacting melamine and formaldehyde at a pH of 10 to 13.
After heating at a temperature of 60 to 80 °C until sulfite is no longer detected in a basic aqueous solution, the pH is adjusted by adding mineral acid.
Adjust to 5-7 and heat to a temperature of 30-70℃,
The condensation product liquid was adjusted to pH 7.5 to 11.0 and condensed at 20°C until the viscosity reached 5 to 40 cp when the solids concentration was 20% by weight, and then a base was added to adjust the pH to 7.5 to 11.0.
This method is characterized by stopping the condensation reaction as 11.0. One major feature of the method of the present invention is that the molar ratio of melamine, formaldehyde and sulfonic acid groups obtained by the method of the present invention is 1:2.7 to 3.2:0.3.
A specific condensation product of melamine formaldehyde having sulfonic groups of 0.7, that is, approximately 1:3:0.5, has excellent water-reducing properties when mixed with cement, and also significantly improves the strength of the hardened cement product. Another major feature of the method of the present invention is that the condensation reaction is particularly carried out in a high pH range, thereby reducing the formation of by-products without reducing the reaction rate. can be evaporated and used as a solid substance with excellent effects, and the condensation reaction time is short. Other features of the method of the invention will be understood from the description below. In the method of the present invention, first, melamine (M), formaldehyde (F) and alkali metal sulfite (S) are mixed in a molar ratio of 1:2.7 to 3.2:0.3 to 0.7, or in the above-mentioned molar ratio. Methylolmelamine and alkali metal sulfite (S) obtained by first reacting formaldehyde (F) with
Heat at a temperature of This is called the first reaction. A method in which melamine and formaldehyde are first reacted to form methylol melamine and then reacted with an alkali metal sulfite is preferable because it causes fewer side reactions than a method in which M, F, and S are directly mixed and reacted. In the first reaction, when the F/M molar ratio is <2.7, the water solubility becomes poor, and precipitates are formed during the condensation reaction, resulting in thickening. Furthermore, if the F/M molar ratio is >3.2, gelation is likely to occur during the condensation reaction, and a water-soluble resin that can be stably stored cannot be obtained. In the first reaction, at S/M molar ratio <0.3,
The resin precipitates out as cloudy during the condensation reaction. Also, if the S/M molar ratio is >0.7, the PH5 in the next condensation reaction is
Under the conditions of ~7, the reaction time becomes long, and although the reaction time can be shortened by lowering the pH to 5 or less, the amount of by-product salt increases and a separation and purification step is required. If the reaction temperature in the first reaction is set to 60°C or lower, a long reaction time is required, and if it is set to 80°C or higher, sulfate by-products increase and the sulfonation rate decreases. In addition, if the pH is less than 10, sulfonation will not proceed sufficiently, and if it is more than 13, it will not have the effect of accelerating sulfonation and will only increase the amount of alkali consumed, which will increase the amount of acid consumed for the next condensation reaction. However, by-product salt will increase. The first reaction is carried out until no sulfite is detected. After the first reaction is completed, a second reaction is performed to advance the condensation reaction. That is, a mineral acid is added to adjust the pH to 5 to 7, and the mixture is heated to a temperature of 30 to 70°C to cause condensation. In the second reaction, when the pH is <5, the amount of by-product salt increases, and when the pH is >7, the condensation reaction is slow and takes a lot of time. Further, if the temperature is below 30°C, it will take a long time, and if it is above 70°C, the sulfone group will be removed and the sulfonation rate will decrease. The second reaction is stopped by adding a base such as NaOH or Ca(OH) 2 to adjust the pH to 7.5-11.0.
The end point of the second reaction is to adjust the pH to 7.5 to 11.0 and at 20°C.
When the solid concentration is 20% by weight, the viscosity is 5~
The range is 40 cp, preferably 7 to 20 cp. A condensate with a viscosity outside this range has little water-reducing effect and little effect on improving the strength of the hardened cement body. The alkali metal sulfites used in the method of the present invention include sulfite groups (SO 3 -2 ), pyrosulfite groups (S 2 O 5 -2 ), acidic sulfite groups (HSO 3 -1 ), etc. and alkali metals, mainly Na or A salt such as K is used. Inorganic and organic alkalis can be used as the PH adjuster in the first reaction, but inorganic alkalis such as sodium hydroxide are preferred. As the mineral acid added in the second reaction, sulfuric acid is preferable since hydrochlorides, nitrates, phosphates, etc., if left in the product, will have an adverse effect on cement etc. 20 of the desired condensation product by the method of the invention
~50% by weight solution is obtained. The content of by-products such as sodium sulfate in the solid material is small at 2 to 3% by weight or less. Therefore, it can be put to practical use as it is or after being concentrated if necessary. This thing,
Alternatively, concentrates have a long pot life and high storage stability. It can also be dried into a powdered product. Water reducing agents are usually dissolved in water and used at an addition rate of several percent or less, approximately 0.1 to 2 percent, based on cement, but liquid products are convenient for manufacturers to supply to users. In particular, the purity of the powder is important since the ratio of powder to cement is small. Since the water reducing agent according to the present invention has a high purity, it is extremely advantageous in terms of use, designing the amount of water added, designing the strength of cured products, etc. As described above, the water reducing agent obtained by the method of the present invention has an excellent water reducing effect, can improve the strength of hardened cement, and is extremely useful for hardening at low temperatures. Furthermore, since the content of by-products is small, there is no adverse effect on the cured product of the hydraulic inorganic material, and it is convenient to handle and use.
Furthermore, the method of the present invention produces less by-products, and can obtain an excellent water reducing agent as described above.
It is an efficient and low-cost method because it requires less time, raw materials, and steps. Next, an example will be described. Example 1 126.0 g (1 g mole) of melamine was placed in a four-necked flask equipped with a reflux condenser, a stirrer, and a thermometer.
Add 225 g of 40% formalin (3 g mol of formaldehyde) and react at pH 7.5 and temperature of 70°C. When the reaction solution becomes transparent, quickly cool to 50°C and add sodium pyrosulfite (Na 2 S 2 O 5 47.5). g (0.25
g mol, equivalent to 0.5 g mol as sulfite), water
730 g and sodium hydroxide were added to adjust the pH to 11.0, and the reaction was carried out for about 1 hour at a temperature of 60° C. until sulfite was no longer detected. Next, the reaction solution was lowered to pH 6.0 with 5% sulfuric acid and the temperature was 60.
Condensation was carried out at ℃. Condensation reaction takes about 1 hour to 1 hour
It took 30 minutes (differences in repeated experiments), neutralized with 20% sodium hydroxide to bring the pH to about 9, cooled to 20°C, stopped the condensation when the viscosity reached 7CP, and continued the process as described above. The mixture was cooled to obtain a condensation product. The solid concentration of the condensation product was 20% by weight, and the sodium sulfate content in the solid was 3% by weight. The condensation product liquid water reducing agent obtained by this method was added to mortar, and the flow value and compressive strength were measured by the method shown in JIS R 5201. The experimental conditions are as follows. Cement: Poldland cement (manufactured by Chichibu Cement) Sand: Standard sand from Toyoura Mixing ratio: Cement/water/sand = 600/300/1200 (parts by weight) Water-cement ratio (W/C): 0.55 Curing conditions: 23℃ Test The results are shown in Table 1 along with comparative examples. Comparative Example 1 The reaction was carried out in the same manner as in Example 1 except that 19 g (0.2 g mol as 0.1 g mol sulfite) of sodium pyrosulfite was used. However, in the condensation reaction, approximately 30
After a few minutes, a self-turbid substance was formed, making further reactions impossible. Comparative Example 2 The reaction was carried out in the same manner as in Example 1 except that 95 g (0.5 g mol, 1 g mol as sulfite) of sodium pyrosulfite was used. However, even if the condensation reaction was carried out for more than 16 hours, the condensation did not proceed, and the solid content was 20% by weight at 20°C.
The condensation was terminated when the viscosity reached 2 cp. Comparative Example 3 In addition to using 76 g (0.4 g mol, 0.8 g mol as sulfite) of sodium pyrosulfite, Example 1
reacted the same way. However, even if the condensation reaction was carried out for more than 10 hours, the condensation did not proceed, and the solid concentration was 20% by weight at 20°C.
The condensation was terminated when the viscosity reached 2.5 cp. Comparative Example 4 Same as Example 1, melamine 88.2g (0.7g mol), 37% formalin 170.3g (formaldehyde
2.1 g mol) and 70 g of sodium pyrosulfite
(0.37 g mol, 0.74 g mol as sulfite) was used to carry out the first reaction. The condensation reaction was carried out at a pH of 4.0. The amount of 50% sulfuric acid required for this was 350 g, which was about 6 times the amount in Example 1. Condensation took approximately 2 hours. After condensation, neutralize with 20% sodium hydroxide, cool to pH9.0, and solidify at 20℃.
An aqueous condensate solution of 21.2% and a viscosity of 8CP was obtained. The product solids contained approximately 20% sodium sulfate. The condensation products of Example 1, Comparative Example 2, and Comparative Example 3 were added as solids to mortar at 0.5% by weight based on cement, and the flow values and compressive strengths were measured under the conditions described above. These are shown in Table 1 together with the same type of water reducing agent (S/M molar ratio 1, F/M molar ratio 3) added (the same amount added).
【表】
第１表から明らかな如く、本発明の方法による
減水剤はすぐれた減水効果を示すと共に顕著な硬
化促進作用を示し、セメントの早期及び長期強度
共に著しく上昇し、低温での硬化にも有用であ
る。[Table] As is clear from Table 1, the water reducing agent according to the method of the present invention exhibits an excellent water reducing effect and a remarkable hardening accelerating effect, significantly increasing both early and long-term strength of cement, and improving hardening at low temperatures. is also useful.
Claims (1)
ンホルムアルデヒド縮合生成物の製法において、
メラミン、ホルムアルデヒド及びアルカリ金属亜
硫酸塩を１：2.7〜3.2：0.3〜0.7のモル比で、又
は前述のモル比でメラミンとホルムアルデヒドを
先に反応せしめて得られたメチロールメラミン及
びアルカリ金属亜硫酸塩を、PH10〜13の塩基性水
溶液中で亜硫酸塩が検出されなくなるまで60〜80
℃の温度で加熱した後、鉱酸を加えてPHを５〜７
に調整して、30〜70℃の温度に加熱し、縮合生成
液がPH7.5〜11.0に調整され20℃で固形物濃度が
20重量％のときの粘度が５〜40cpになるまで、
縮合した後、塩基を加えてPHを7.5〜11.0として
縮合反応を停止せしめることを特徴とする高性能
減水剤の製法。1. In a method for producing a melamine formaldehyde condensation product having a sulfonic acid group as a water reducing agent,
Melamine, formaldehyde and alkali metal sulfite in a molar ratio of 1:2.7 to 3.2:0.3 to 0.7, or methylolmelamine and alkali metal sulfite obtained by first reacting melamine and formaldehyde in the above molar ratio, 60-80 until sulfites are no longer detected in basic aqueous solutions with pH 10-13
After heating at a temperature of ℃, add mineral acid to adjust the pH to 5-7
The condensation product liquid is adjusted to a pH of 7.5 to 11.0, and the solids concentration is reduced to 20℃.
Until the viscosity at 20% by weight is 5 to 40 cp,
A method for producing a high performance water reducing agent, which comprises, after condensation, adding a base to adjust the pH to 7.5 to 11.0 to stop the condensation reaction.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP11290879A JPS5638315A (en) | 1979-09-05 | 1979-09-05 | Preparation of high-performance dispersing agent |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP11290879A JPS5638315A (en) | 1979-09-05 | 1979-09-05 | Preparation of high-performance dispersing agent |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5638315A JPS5638315A (en) | 1981-04-13 |
| JPS6158082B2 true JPS6158082B2 (en) | 1986-12-10 |
Family
ID=14598496
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP11290879A Granted JPS5638315A (en) | 1979-09-05 | 1979-09-05 | Preparation of high-performance dispersing agent |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5638315A (en) |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE1745441A1 (en) * | 1968-03-11 | 1975-01-16 | Sueddeutsche Kalkstickstoff | PROCESS FOR THE PREPARATION OF SOLUTIONS OF SULPHITE-MODIFIED MELAMINE RESINS |
-
1979
- 1979-09-05 JP JP11290879A patent/JPS5638315A/en active Granted
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE1745441A1 (en) * | 1968-03-11 | 1975-01-16 | Sueddeutsche Kalkstickstoff | PROCESS FOR THE PREPARATION OF SOLUTIONS OF SULPHITE-MODIFIED MELAMINE RESINS |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5638315A (en) | 1981-04-13 |
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