JPH0134942B2 - - Google Patents
Info
- Publication number
- JPH0134942B2 JPH0134942B2 JP7319081A JP7319081A JPH0134942B2 JP H0134942 B2 JPH0134942 B2 JP H0134942B2 JP 7319081 A JP7319081 A JP 7319081A JP 7319081 A JP7319081 A JP 7319081A JP H0134942 B2 JPH0134942 B2 JP H0134942B2
- Authority
- JP
- Japan
- Prior art keywords
- parts
- weight
- magnesia
- water
- magnesia cement
- 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
- CPLXHLVBOLITMK-UHFFFAOYSA-N Magnesium oxide Chemical class [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 claims description 95
- 239000000395 magnesium oxide Substances 0.000 claims description 44
- 239000004568 cement Substances 0.000 claims description 36
- TWRXJAOTZQYOKJ-UHFFFAOYSA-L Magnesium chloride Chemical compound [Mg+2].[Cl-].[Cl-] TWRXJAOTZQYOKJ-UHFFFAOYSA-L 0.000 claims description 24
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 20
- CSNNHWWHGAXBCP-UHFFFAOYSA-L Magnesium sulfate Chemical compound [Mg+2].[O-][S+2]([O-])([O-])[O-] CSNNHWWHGAXBCP-UHFFFAOYSA-L 0.000 claims description 17
- 239000000203 mixture Substances 0.000 claims description 15
- 229910019142 PO4 Inorganic materials 0.000 claims description 13
- 229910000288 alkali metal carbonate Inorganic materials 0.000 claims description 12
- 150000008041 alkali metal carbonates Chemical class 0.000 claims description 12
- 229910001629 magnesium chloride Inorganic materials 0.000 claims description 12
- 239000010452 phosphate Substances 0.000 claims description 12
- NBIIXXVUZAFLBC-UHFFFAOYSA-K phosphate Chemical compound [O-]P([O-])([O-])=O NBIIXXVUZAFLBC-UHFFFAOYSA-K 0.000 claims description 12
- 229910052943 magnesium sulfate Inorganic materials 0.000 claims description 8
- 235000019341 magnesium sulphate Nutrition 0.000 claims description 8
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 claims description 6
- BWHMMNNQKKPAPP-UHFFFAOYSA-L potassium carbonate Chemical compound [K+].[K+].[O-]C([O-])=O BWHMMNNQKKPAPP-UHFFFAOYSA-L 0.000 claims description 4
- 229910000029 sodium carbonate Inorganic materials 0.000 claims description 3
- XGZVUEUWXADBQD-UHFFFAOYSA-L lithium carbonate Chemical group [Li+].[Li+].[O-]C([O-])=O XGZVUEUWXADBQD-UHFFFAOYSA-L 0.000 claims description 2
- 229910052808 lithium carbonate Inorganic materials 0.000 claims description 2
- 229910000027 potassium carbonate Inorganic materials 0.000 claims description 2
- LRXTYHSAJDENHV-UHFFFAOYSA-H zinc phosphate Chemical compound [Zn+2].[Zn+2].[Zn+2].[O-]P([O-])([O-])=O.[O-]P([O-])([O-])=O LRXTYHSAJDENHV-UHFFFAOYSA-H 0.000 claims description 2
- 229910000165 zinc phosphate Inorganic materials 0.000 claims description 2
- GVALZJMUIHGIMD-UHFFFAOYSA-H magnesium phosphate Chemical group [Mg+2].[Mg+2].[Mg+2].[O-]P([O-])([O-])=O.[O-]P([O-])([O-])=O GVALZJMUIHGIMD-UHFFFAOYSA-H 0.000 claims 1
- 235000021317 phosphate Nutrition 0.000 description 11
- 239000013078 crystal Substances 0.000 description 9
- 230000007774 longterm Effects 0.000 description 6
- VTHJTEIRLNZDEV-UHFFFAOYSA-L magnesium dihydroxide Chemical compound [OH-].[OH-].[Mg+2] VTHJTEIRLNZDEV-UHFFFAOYSA-L 0.000 description 6
- 239000000347 magnesium hydroxide Substances 0.000 description 6
- 229910001862 magnesium hydroxide Inorganic materials 0.000 description 6
- 238000005452 bending Methods 0.000 description 5
- 150000003839 salts Chemical class 0.000 description 5
- 239000002002 slurry Substances 0.000 description 5
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 4
- 230000015572 biosynthetic process Effects 0.000 description 4
- 238000001723 curing Methods 0.000 description 4
- 230000000694 effects Effects 0.000 description 4
- 238000002156 mixing Methods 0.000 description 4
- 150000008064 anhydrides Chemical class 0.000 description 3
- 239000007864 aqueous solution Substances 0.000 description 3
- 238000013007 heat curing Methods 0.000 description 3
- 239000011777 magnesium Substances 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 238000000034 method Methods 0.000 description 3
- 230000000704 physical effect Effects 0.000 description 3
- VTYYLEPIZMXCLO-UHFFFAOYSA-L Calcium carbonate Chemical compound [Ca+2].[O-]C([O-])=O VTYYLEPIZMXCLO-UHFFFAOYSA-L 0.000 description 2
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 2
- 230000008901 benefit Effects 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- -1 etc. Substances 0.000 description 2
- 238000007654 immersion Methods 0.000 description 2
- 229920000126 latex Polymers 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- KFHHGNBIPJDZPH-UHFFFAOYSA-D pentamagnesium [oxido(phosphonatooxy)phosphoryl] phosphate Chemical compound [Mg+2].[Mg+2].[Mg+2].[Mg+2].[Mg+2].[O-]P([O-])(=O)OP([O-])(=O)OP([O-])([O-])=O.[O-]P([O-])(=O)OP([O-])(=O)OP([O-])([O-])=O KFHHGNBIPJDZPH-UHFFFAOYSA-D 0.000 description 2
- 239000004576 sand Substances 0.000 description 2
- 229920002994 synthetic fiber Polymers 0.000 description 2
- BVKZGUZCCUSVTD-UHFFFAOYSA-L Carbonate Chemical compound [O-]C([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-L 0.000 description 1
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 1
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 1
- JLVVSXFLKOJNIY-UHFFFAOYSA-N Magnesium ion Chemical compound [Mg+2] JLVVSXFLKOJNIY-UHFFFAOYSA-N 0.000 description 1
- 229920000388 Polyphosphate Polymers 0.000 description 1
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 description 1
- 239000012615 aggregate Substances 0.000 description 1
- 229910052783 alkali metal Inorganic materials 0.000 description 1
- 229910001413 alkali metal ion Inorganic materials 0.000 description 1
- 238000007664 blowing Methods 0.000 description 1
- 239000004566 building material Substances 0.000 description 1
- 229910000019 calcium carbonate Inorganic materials 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 238000010924 continuous production Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- 238000002050 diffraction method Methods 0.000 description 1
- 239000003822 epoxy resin Substances 0.000 description 1
- 239000000835 fiber Substances 0.000 description 1
- 239000000945 filler Substances 0.000 description 1
- 238000010304 firing Methods 0.000 description 1
- 238000009415 formwork Methods 0.000 description 1
- 239000004816 latex Substances 0.000 description 1
- 238000002386 leaching Methods 0.000 description 1
- 229910052749 magnesium Inorganic materials 0.000 description 1
- ZLNQQNXFFQJAID-UHFFFAOYSA-L magnesium carbonate Chemical compound [Mg+2].[O-]C([O-])=O ZLNQQNXFFQJAID-UHFFFAOYSA-L 0.000 description 1
- 239000001095 magnesium carbonate Substances 0.000 description 1
- 229910000021 magnesium carbonate Inorganic materials 0.000 description 1
- 229910001425 magnesium ion Inorganic materials 0.000 description 1
- 239000002557 mineral fiber Substances 0.000 description 1
- 239000010451 perlite Substances 0.000 description 1
- 235000019362 perlite Nutrition 0.000 description 1
- 150000003013 phosphoric acid derivatives Chemical class 0.000 description 1
- 229920000647 polyepoxide Polymers 0.000 description 1
- 239000001205 polyphosphate Substances 0.000 description 1
- 235000011176 polyphosphates Nutrition 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 238000002407 reforming Methods 0.000 description 1
- 239000012779 reinforcing material Substances 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- 239000011734 sodium Substances 0.000 description 1
- 230000035900 sweating Effects 0.000 description 1
- 239000012209 synthetic fiber Substances 0.000 description 1
- 229920003002 synthetic resin Polymers 0.000 description 1
- 239000000057 synthetic resin Substances 0.000 description 1
- 238000010998 test method Methods 0.000 description 1
- 239000010455 vermiculite Substances 0.000 description 1
- 229910052902 vermiculite Inorganic materials 0.000 description 1
- 235000019354 vermiculite Nutrition 0.000 description 1
- 230000004580 weight loss Effects 0.000 description 1
- 239000011701 zinc Substances 0.000 description 1
Classifications
-
- 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
- C04B28/30—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 magnesium cements or similar cements
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Ceramic Engineering (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Inorganic Chemistry (AREA)
- Materials Engineering (AREA)
- Structural Engineering (AREA)
- Organic Chemistry (AREA)
- Curing Cements, Concrete, And Artificial Stone (AREA)
Description
本発明はマグネシアセメント組成物に関する。
マグネシアセメントは一般に活性マグネシアに
塩化マグネシウム及び／又は硫酸マグネシウムを
混合してなる水性組成物であつて、他のセメント
に比較して曲げ強度、硬度が高く、また、表面光
沢にすぐれているほか、特に硬化物が不燃性であ
るので、建材等の分野において従来の有機合成材
料に代替し、その可燃性の問題を解消し得る材料
として注目されている。さらに、マグネシアセメ
ントは硬化時間が比較的短かいため、板状体、柱
状体等の成形物の工場生産に都合がよい利点も併
せ有している。
しかしながら、一方においてマグネシアセメン
トは硬化後に可溶性塩類が溶出するために耐水性
に欠ける憾みがあり、水分や湿気の多い場所での
使用は避けざるを得ず、このため用途が非常に限
定される問題があつた。このように耐水性に欠け
る問題を解決するために、例えば、マグネシアセ
メントに水溶性のポリリン酸塩を添加することが
提案されているが（米国特許第3320077号）、耐水
性の改良は十分でなく、むしろ、硬化時間を長く
して、マグネシアセメントの利点を損なう傾向が
ある。一方、硬化時間を短かくするために、マグ
ネシアセメントの硬化時に加熱して硬化を促進さ
せることも既に知られているが、一般に従来のマ
グネシアセメントを加熱して硬化させたとき、常
温で硬化させた場合に比べて長期強度物性が劣る
問題があつた。
本発明はマグネシアセメントにおける上記した
種々の問題を解決するためになされたものであつ
て、耐水性にすぐれた硬化体を与えると共に、硬
化性、特に加熱硬化性にすぐれ、さらに硬化体の
初期及び長期強度物性が良好であるマグネシアセ
メント組成物を提供する目的とする。
本発明のマグネシアセメント組成物は、(a)活性
マグネシア100重量部と、(b)塩化マグネシウム20
〜60重量部及び／又は硫酸マグネシウム15〜100
重量部と、(c)水不溶性リン酸塩５〜60重量部と、
(d)アルカリ金属炭酸塩５〜20重量部と、(e)水60〜
210重量部とからなることを特徴とする。
本発明において用いる活性マグネシアは比較的
高い活性度を有することが好ましい。このような
活性マグネシアは普通、水酸化マグネシウム、炭
酸マグネシウム等を400〜1000℃で焼成すること
により得られるが、好ましくは600〜900℃の温度
で焼成した活性マグネシアが用いられる。
塩化マグネシウムは無水物換算で活性マグネシ
ア100重量部について20〜60重量部用いられる。
20重量部より少ないときは、マグネシアセメント
の硬化直後の初期強度が小さく、過剰のマグネシ
アが表面に吹き出る所謂粉吹き現象が起こり、60
重量部より多いときは、過剰の塩化マグネシウム
が所謂発汗現象を起こす。硫酸マグネシウムは無
水物換算で活性マグネシア100重量部について15
〜100重量部用いられる。15重量部より少ないと
きは、一般に硬化体の強度が小さく、一方、100
重量部より多いときは、特に加熱硬化後の初期硬
度が乏しく、例えば成形品の製造において成形品
を型枠から脱型する際に硬化体が型崩れすること
があるので好ましくない。
塩化マグネシウムと硫酸マグネシウムはそれぞ
れ単独で用いられてもよいが、また、併用されて
もよい。両者を併用する場合、その割合は硫酸マ
グネシウム１モルについて塩化マグネシウム0.4
〜５モルであつて、その合計量は活性マグネシア
100重量部について25〜75重量部が好ましい。
本発明のマグネシアセメント組成物は、無水物
換算で活性マグネシア100重量部について水不溶
性リン酸塩５〜60重量部、アルカリ金属炭酸塩５
〜20重量部とを含有する。
従来のマグネシアセメントは、これを加熱する
と急速に硬化し、型枠から容易に脱型することが
できるが、この場合、硬化時に一部水酸化マグネ
シウムが生成することが主たる原因となつて、硬
化体内に細かいクラツクが多数発生し、前記した
ように長期強度に劣ることとなる。また、従来の
マグネシアセメント硬化体は水中に長期に曝され
ると、マグネシアセメント複塩結晶が分解し、可
溶性塩として溶出するため、硬化体はその重量を
減少して水酸化マグネシウムの多孔体となると共
に、強度が著しく低下する。
本発明のマグネシアセメント組成物によれば、
水不溶性リン酸塩とアルカリ金属炭酸塩を併用す
ることにより、硬化時、特に加熱硬化時に水酸化
マグネシウムの生成を抑えて、マグネシアセメン
ト複塩結晶の生成を促進し、水に浸漬時にもマグ
ネシアセメント複塩結晶を安定化し、このように
して加熱硬化性が良好で長期強度にすぐれ、か
つ、耐水性も著しく改善されるのである。本発明
のマグネシアセメント組成物は何ら理論により制
約を受けるものではないが、アルカリ金属炭酸塩
はマグネシアセメント結晶中のマグネシウムイオ
ンや塩素イオン、硫酸イオンを一部アルカリ金属
イオンや炭酸イオンと置換し、又はマグネシアセ
メント結晶に吸着し、水不溶性リン酸塩と共に上
記したような効果を発現すると考えられる。
本発明において水不溶性リン酸塩としては、具
体的には第三リン酸マグネシウム（Mg3
（PO4）2・8H2O）、リン酸亜鉛（Zn3（PO4）2・
4H2O）等が用いられ、また、アルカリ金属炭酸
塩としては炭酸リチウム、炭酸カリウム、炭酸ナ
トリウム等が用いられる。
水不溶性リン酸塩の配合量が少なすぎるとき
は、マグネシアセメント結晶の改質効果が十分に
発現されず、また、多すぎるときは、マグネシア
セメントにおける活性マグネシアと、硬化剤塩化
マグネシウム及び／又は硫酸マグネシウムの量が
相対的に少なくなり、加熱硬化時の初期強度及び
長期強度が十分に大きくないので好ましくない。
また、アルカリ金属炭酸塩の配合量が少なすぎ
るときは、上記のような改質効果が十分でなく、
一方、多すぎるときは、マグネシアセメントにお
ける活性マグネシア、塩化マグネシウム及び／又
は硫酸マグネシウムの量が相対的に減少するの
で、粘度が高くなつて成形性に支障を生じるほ
か、マグネシアセメント結晶の生成は促進される
が、硬化体の密度の低下、強度低下等が起こるの
で好ましくない。
本発明のマグネシアセメント組成物において、
水不溶性リン酸塩及びアルカリ金属炭酸塩の配合
の方法は特に限定されず、例えば塩化マグネシウ
ム及び／又は硫酸マグネシウムの水溶液に添加し
てもよく、また、塩化マグネシウム及び／又は硫
酸マグネシウムの水溶液に活性マグネシアを加え
てスラリーとし、このスラリーに添加してもよ
い。
マグネシアセメント組成物における水は、活性
マグネシア100重量部について通常、60〜210重量
部である。この水は、通常、塩化マグネシウム及
び／又は硫酸マグネシウムの水溶液やアルカリ金
属炭酸塩の水溶液の形で配合されるが、しかし、
これらの方法に限定されるものではない。
本発明においては、得られる硬化体を補強し、
また、クラツクの発生を防止するために、マグネ
シアセメント組成物は天然繊維、合成繊維、鉱物
繊維等の適宜の補強材を必要に応じて含有してい
てもよく、また、炭酸カルシウム、パーライト、
ひる石、砂、ケイ砂、砂利等の充填材及び骨材を
The present invention relates to magnesia cement compositions. Magnesia cement is generally an aqueous composition made by mixing activated magnesia with magnesium chloride and/or magnesium sulfate, and has higher bending strength and hardness than other cements, as well as excellent surface gloss. In particular, since the cured product is nonflammable, it is attracting attention as a material that can replace conventional organic synthetic materials in the field of building materials and solve the problem of flammability. Furthermore, since magnesia cement has a relatively short curing time, it also has the advantage of being convenient for factory production of molded products such as plates and columns. However, on the other hand, magnesia cement suffers from a lack of water resistance due to the leaching of soluble salts after hardening, and its use in areas with high moisture or humidity must be avoided, resulting in the problem that its applications are extremely limited. It was hot. In order to solve this problem of lack of water resistance, it has been proposed, for example, to add water-soluble polyphosphate to magnesia cement (US Pat. No. 3,320,077), but the improvement in water resistance is not sufficient. On the contrary, it tends to lengthen the curing time and negate the benefits of magnesia cement. On the other hand, it is already known that magnesia cement can be heated to accelerate hardening in order to shorten the hardening time. There was a problem that the long-term strength and physical properties were inferior to that of the conventional method. The present invention has been made in order to solve the above-mentioned various problems in magnesia cement, and provides a hardened product with excellent water resistance, excellent hardening properties, especially heat hardening properties, and furthermore, The object of the present invention is to provide a magnesia cement composition having good long-term strength properties. The magnesia cement composition of the present invention comprises (a) 100 parts by weight of activated magnesia, and (b) 20 parts by weight of magnesium chloride.
~60 parts by weight and/or 15-100 parts magnesium sulfate
parts by weight; (c) 5 to 60 parts by weight of a water-insoluble phosphate;
(d) 5 to 20 parts by weight of alkali metal carbonate; (e) 60 to 60 parts by weight of water;
210 parts by weight. The activated magnesia used in the present invention preferably has a relatively high degree of activity. Such activated magnesia is usually obtained by firing magnesium hydroxide, magnesium carbonate, etc. at a temperature of 400 to 1000°C, but activated magnesia fired at a temperature of 600 to 900°C is preferably used. Magnesium chloride is used in an amount of 20 to 60 parts by weight per 100 parts by weight of active magnesia in terms of anhydride.
When the amount is less than 20 parts by weight, the initial strength of the magnesia cement immediately after hardening is low, and a so-called powder blowing phenomenon occurs in which excess magnesia blows out onto the surface.
When the amount is more than part by weight, excess magnesium chloride causes the so-called sweating phenomenon. Magnesium sulfate is 15% per 100 parts by weight of active magnesia in terms of anhydride.
~100 parts by weight are used. When it is less than 15 parts by weight, the strength of the cured product is generally low;
When the amount is more than 1 part by weight, the initial hardness after heat curing is particularly poor, and the cured product may lose its shape, for example, when the molded product is removed from the mold in the production of a molded product, which is not preferable. Magnesium chloride and magnesium sulfate may be used alone or in combination. When both are used together, the ratio is 1 mole of magnesium sulfate to 0.4 magnesium chloride.
~5 moles, the total amount of which is active magnesia
25 to 75 parts by weight per 100 parts by weight are preferred. The magnesia cement composition of the present invention contains 5 to 60 parts by weight of water-insoluble phosphate and 5 parts by weight of alkali metal carbonate for 100 parts by weight of active magnesia in terms of anhydride.
~20 parts by weight. Conventional magnesia cement hardens rapidly when heated and can be easily removed from the mold, but in this case, some magnesium hydroxide is produced during hardening, which is the main cause of hardening. Many small cracks occur in the body, resulting in poor long-term strength as described above. In addition, when conventional hardened magnesia cement is exposed to water for a long period of time, the magnesia cement double salt crystals decompose and are eluted as soluble salts, so the hardened material loses its weight and becomes a porous body of magnesium hydroxide. At the same time, the strength decreases significantly. According to the magnesia cement composition of the present invention,
By using water-insoluble phosphate and alkali metal carbonate together, the formation of magnesium hydroxide is suppressed during hardening, especially during heat curing, and the formation of magnesia cement double salt crystals is promoted. The double salt crystals are stabilized, and in this way, it has good heat curability, excellent long-term strength, and markedly improved water resistance. Although the magnesia cement composition of the present invention is not limited by any theory, the alkali metal carbonate replaces some of the magnesium ions, chloride ions, and sulfate ions in the magnesia cement crystals with alkali metal ions and carbonate ions, Alternatively, it is considered that it is adsorbed to magnesia cement crystals and exerts the above-mentioned effects together with water-insoluble phosphate. In the present invention, the water-insoluble phosphate is specifically magnesium triphosphate (Mg 3
(PO 4 ) 2・8H 2 O), zinc phosphate (Zn 3 (PO 4 ) 2・
4H 2 O), etc., and as the alkali metal carbonate, lithium carbonate, potassium carbonate, sodium carbonate, etc. are used. If the amount of water-insoluble phosphate is too small, the effect of modifying the magnesia cement crystals will not be sufficiently expressed, and if it is too large, the active magnesia in the magnesia cement and the hardening agent magnesium chloride and/or sulfuric acid This is not preferable because the amount of magnesium is relatively small and the initial strength and long-term strength during heat curing are not sufficiently high. In addition, if the amount of alkali metal carbonate blended is too small, the above-mentioned reforming effect will not be sufficient, and
On the other hand, if the amount is too high, the amount of active magnesia, magnesium chloride and/or magnesium sulfate in magnesia cement will be relatively reduced, which will increase the viscosity and hinder formability, and will also accelerate the formation of magnesia cement crystals. However, this is not preferable because it causes a decrease in the density and strength of the cured product. In the magnesia cement composition of the present invention,
The method of blending water-insoluble phosphates and alkali metal carbonates is not particularly limited; for example, they may be added to an aqueous solution of magnesium chloride and/or magnesium sulfate; Magnesia may be added to form a slurry and added to this slurry. Water in magnesia cement compositions is typically 60 to 210 parts by weight per 100 parts by weight of active magnesia. This water is usually formulated in the form of an aqueous solution of magnesium chloride and/or magnesium sulfate or an aqueous solution of alkali metal carbonate, but
The method is not limited to these methods. In the present invention, the obtained cured product is reinforced,
Furthermore, in order to prevent the occurrence of cracks, the magnesia cement composition may contain appropriate reinforcing materials such as natural fibers, synthetic fibers, mineral fibers, etc., and calcium carbonate, perlite,
Fillers and aggregates such as vermiculite, sand, silica sand, gravel, etc.
【表】
含有していてもよい。さらに、ゴムラテツクスや
エポキシ樹脂等の合成樹脂ラテツクスを配合し、
得られる硬化体の耐水性を一層高めることもでき
る。
本発明のマグネシアセメント組成物は、以上の
ように、水不溶性リン酸塩とアルカリ金属炭酸塩
とを配合することにより、得られる硬化体は著し
く耐水性にすぐれるのみならず、硬化特性、特に
加熱硬化性が良好で、しかも硬化体の初期及び長
期強度が大きく、従つて、広範囲の用途に用いる
ことができると共に、脱型性が良好であるため、
成形品等の大量連続生産に好適である。
以下に本発明の実施例を比較例と共に挙げる
が、本発明はこれら実施例により限定されるもの
ではない。なお、部は重量部を意味する。
実施例 １
活性マグネシア（800℃で焼成したもの。以下
も同じである。）100部、塩化マグネシウム30部、
第三リン酸マグネシウム（Mg3（PO4）2・8H2O）
５部、炭酸ナトリウム（Na2CO3・H2O）５部及
び水90重量部からなるマグネシアセメントスラリ
ーを型枠に注入し、次に、75℃の温度に急速に加
熱し、30分間この温度に保つた後、成形品を型枠
から脱型したが、型崩れは起こらなかつた。脱型
直後及び常温での養生後の曲げ強度を建築用ボー
ド類の曲げ試験法（JIS Ａ−1408）に準じて測定
した。結果を表に示す。
また、常温で28日間養生後の成形品を常温の流
水（２／分）に浸漬し、その重量減少率から耐
水性を評価した。さらに、28日間常温養生した成
形品を上記の条件で28日間流水の浸漬した後、Ｘ
線回折法によりマグネシアセメント結晶中の水酸
化マグネシウムの生成の有無を調べ、同時にその
曲げ強度も調べた。これらの結果を表に併せて示
す。
実施例 ２〜５
表に示す組成のマグネシアセメントスラリーを
用いて実施例１と同様にして成形品を得、物性を
調べた。結果を表に示す。
比較例 １〜６
表に示す組成のマグネシアセメントスラリーを
用いて実施例１と同様にして成形品を得、物性を
調べた。結果を表に示す。
以上から明らかなように、水溶性のリン酸塩を
配合しても耐水性の改善は僅かであるが、本発明
によつて、水不溶性のリン酸塩とアルカリ金属塩
とを配合することにより、水酸化マグネシウムの
生成が抑えられると共に、流水に浸漬後もマグネ
シアセメント結晶の分解が抑えられ、耐水性、強
度が改善される。特に、水不溶性リン酸塩又はア
ルカリ金属炭酸塩を併用することにより、単独で
配合する場合に比べて、流水浸漬後曲げ強度が格
段に改善される。[Table] May contain. Furthermore, synthetic resin latex such as rubber latex and epoxy resin is blended,
It is also possible to further improve the water resistance of the resulting cured product. As described above, in the magnesia cement composition of the present invention, by blending a water-insoluble phosphate and an alkali metal carbonate, the resulting cured product not only has excellent water resistance, but also has hardening properties, especially It has good heat curability and high initial and long-term strength of the cured product, so it can be used in a wide range of applications and has good demoldability.
Suitable for mass continuous production of molded products, etc. Examples of the present invention are listed below along with comparative examples, but the present invention is not limited to these Examples. In addition, parts mean parts by weight. Example 1 100 parts of activated magnesia (calcined at 800°C. The same applies below), 30 parts of magnesium chloride,
Magnesium triphosphate (Mg 3 (PO 4 ) 2・8H 2 O)
A magnesia cement slurry consisting of 5 parts of sodium carbonate (Na 2 CO 3 H 2 O) and 90 parts by weight of water was poured into the formwork, then rapidly heated to a temperature of 75 °C and kept at this temperature for 30 minutes. After maintaining the molded product at a certain temperature, the molded product was removed from the mold, but the molded product did not lose its shape. The bending strength immediately after demolding and after curing at room temperature was measured according to the bending test method for architectural boards (JIS A-1408). The results are shown in the table. In addition, the molded product after curing for 28 days at room temperature was immersed in running water (2/min) at room temperature, and water resistance was evaluated from the weight loss rate. Furthermore, the molded product that had been cured at room temperature for 28 days was immersed in running water for 28 days under the above conditions, and then
The presence or absence of magnesium hydroxide formation in magnesia cement crystals was investigated using a line diffraction method, and at the same time, its bending strength was also investigated. These results are also shown in the table. Examples 2 to 5 Molded articles were obtained in the same manner as in Example 1 using magnesia cement slurries having the compositions shown in the table, and their physical properties were examined. The results are shown in the table. Comparative Examples 1 to 6 Molded articles were obtained in the same manner as in Example 1 using magnesia cement slurries having the compositions shown in the table, and their physical properties were examined. The results are shown in the table. As is clear from the above, even if a water-soluble phosphate is blended, the water resistance is only slightly improved; however, according to the present invention, by blending a water-insoluble phosphate and an alkali metal salt. In addition to suppressing the production of magnesium hydroxide, decomposition of magnesia cement crystals is also suppressed even after immersion in running water, and water resistance and strength are improved. In particular, by using a water-insoluble phosphate or an alkali metal carbonate in combination, the bending strength after immersion in running water is significantly improved compared to when they are used alone.
Claims (1)
ネシウム20〜60重量部及び／又は硫酸マグネシウ
ム15〜100重量部と、(c)水不溶性リン酸塩５〜60
重量部と、(d)アルカリ金属炭酸塩５〜20重量部
と、(e)水60〜210重量部とからなることを特徴と
するマグネシアセメント組成物。 ２ 水不溶性リン酸塩が第三リン酸マグネシウム
又はリン酸亜鉛であることを特徴とする特許請求
の範囲第１項記載のマグネシアセメント組成物。 ３ アルカリ金属炭酸塩が炭酸リチウム、炭酸カ
リウム又は炭酸ナトリウムであることを特徴とす
る特許請求の範囲第１項記載のマグネシアセメン
ト組成物。[Scope of Claims] 1 (a) 100 parts by weight of activated magnesia, (b) 20 to 60 parts by weight of magnesium chloride and/or 15 to 100 parts by weight of magnesium sulfate, and (c) 5 to 60 parts by weight of a water-insoluble phosphate.
(d) 5 to 20 parts by weight of an alkali metal carbonate, and (e) 60 to 210 parts by weight of water. 2. The magnesia cement composition according to claim 1, wherein the water-insoluble phosphate is tribasic magnesium phosphate or zinc phosphate. 3. The magnesia cement composition according to claim 1, wherein the alkali metal carbonate is lithium carbonate, potassium carbonate, or sodium carbonate.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7319081A JPS57188439A (en) | 1981-05-14 | 1981-05-14 | Magnesia cement composition |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7319081A JPS57188439A (en) | 1981-05-14 | 1981-05-14 | Magnesia cement composition |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS57188439A JPS57188439A (en) | 1982-11-19 |
| JPH0134942B2 true JPH0134942B2 (en) | 1989-07-21 |
Family
ID=13510967
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP7319081A Granted JPS57188439A (en) | 1981-05-14 | 1981-05-14 | Magnesia cement composition |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS57188439A (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS63502103A (en) * | 1986-01-07 | 1988-08-18 | オ−スミンテック・コ−ポレ−ション・リミテッド | magnesium cement |
| US5039454A (en) * | 1990-05-17 | 1991-08-13 | Policastro Peter P | Zinc-containing magnesium oxychloride cements providing fire resistance and an extended pot-life |
| PL192018B1 (en) * | 1995-12-05 | 2006-08-31 | Dolomatrix Internat Ltd | Binder composition and application thereof |
| WO2001055049A1 (en) | 2000-01-27 | 2001-08-02 | Tececo Pty Ltd | Reactive magnesium oxide cements |
-
1981
- 1981-05-14 JP JP7319081A patent/JPS57188439A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS57188439A (en) | 1982-11-19 |
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