Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Processes of preparing a desired or intentional composition...
Reexamination Certificate
2001-06-20
2004-01-20
Lipman, Bernard (Department: 1713)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Processes of preparing a desired or intentional composition...
C106S724000, C106S727000, C106S728000, C106S823000, C524S004000, C524S005000, C526S304000
Reexamination Certificate
active
06680348
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a cement dispersant and a concrete composition containing the dispersant. In more detail, the present invention relates to a cement dispersant having superior dispersion effect of cement particles and its retention, thereby obtaining greater water-reducing effect and long slump flow retention, so that a workability is excellent and strength development after hardening is good, particularly a cement dispersant suitable for concretes with ultrahigh performance, and a concrete composition such as an ultrahigh performance concrete composition containing the dispersant.
BACKGROUND ART
Polycarboxylic acid type dispersants such as a copolymer of polymelamine sulfonate, lignin sulfonate, olefin and maleic acid and the like have conventionally been used as a cement dispersant. However, these compounds have problems in not only their effect connoting as slump flow retention effect, but their suitability in existing as well as future ultrahigh performance concrete.
New type polycarboxylic acid type cement dispersants having nonionic groups introduced therein are positively proposed to solve these problems. For example, JP-A 1-226757 discloses a copolymer of (meth)acrylate, (meth)acryl sulfonate, and monoacrylate ester of polyethylene glycol alkyl ether or monoacrylate ester of polypropylene glycol alkyl ether. However, conventional cement dispersants including the one disclosed in the above publication have not yet been satisfactory as to all of water reducing effect, slump flow retention, strength development and the like in order to use as a compounded concrete with said dispersants.
Therefore, there is a strong call in the industry for cement dispersants meeting sufficient water reducing effect, slump flow retention, strength development and the like, applicable even to ultrahigh performance concrete.
The present invention has been made to meet this demand, and has an object to provide a cement dispersant with satisfactory water reducing effect, slump flow retention, strength development and the like, and a concrete composition containing said dispersant in order to solve the problems existing in the prior art.
DISCLOSURE OF INVENTION
After extensive investigation into finding the solution for the problems, the present inventors have found a copolymer comprising three specific organic substances with the desired effect, and have completed the present invention as described.
That is, the present invention relates to a cement dispersant comprising a water soluble amphoteric copolymer, as a main component, obtained by copolymerizing an addition product(compound A) obtained by the addition of 0-8 moles of an alkylene oxide having 2 to 4 carbon atoms to one equivalent of amino residues in polyamide polyamine obtained by condensation of 1.0 mole of a polyalkylene polyamine, 0.8-0.95 mole of a dibasic acid or an ester of the dibasic acid with a lower alcohol having 1 to 4 carbon atoms, and 0.05-0.18 mole of acrylic acid or methacrylic acid, or an ester of acrylic acid or methacrylic acid with a lower alcohol having 1 to 4 carbon atoms, and a compound (compound B) of the formula I:
(wherein R is hydrogen atom or methyl group, and M is hydrogen atom, alkali metal, ammonium group or alkanolammonium group), and a compound (compound C) of the formula II:
(wherein R′ is hydrogen atom or methyl group, R
1
is C
2
-C
4
alkylene group, R
2
is hydrogen atom or C
1
-C
4
alkyl group, and m is an integer of 1 to 100), in the ratio of compound A:compound B:compound C=10-40% by weight:10-40% by weight:50-80% by weight.
The present invention also particularly relates to said cement dispersant of the present invention used in an ultrahigh performance concrete composition.
The cement dispersant of the present invention can also be used as a general purpose high performance AE water reducing agent by blending techniques available for regular concrete.
The present invention further relates to a concrete composition characterized by having said cement dispersant of the present invention, and particularly the concrete composition for an ultrahigh-performance concrete. The “ultrahigh performance concrete” described herewith denotes concrete generally used and understood in the pertinent art, and encompasses concretes in considerably broad range, and includes, for example, concrete showing strength equal to or higher than the conventional concrete even when less amount of water is used as compared with the conventional concrete, or more specifically concrete that provides a highly workable ready-mixed concrete without interfering in general use even when a water/binder ratio is 20% or less, particularly about 12%, and yet with a compression strength of 150 N/mm
2
or more upon hardening.
As described above, the compound A used in the present invention is an addition product obtained by the addition of specific amount of an alkylene oxide (compound d) to the polyamide polyamine achieved by condensation of a polyalkylene polyamine (compound a), a dibasic acid or an ester of the dibasic acid with a lower alcohol having 1 to 4 carbon atoms (compound b), and acrylic acid or methacrylic acid, or an ester of acrylic acid or methacrylic acid with a lower alcohol having 1 to 4 carbon atoms (compound c), in a definite proportion.
Examples of the polyalkylene polyamine of the compound a include diethylene triamine, triethylene tetramine, tetraethylene pentamine, pentaethylene hexamine, dipropylene triamine, tripropylene tetramine and tetrapropylene pentamine, but diethylene triamine and triethylene tetramine are preferable from both points of effectiveness and economical angle.
Examples of the dibasic acid and its lower alcohol ester having 1 to 4 carbon atoms of the compound b include, for example, malonic acid, succinic acid, fumaric acid, maleic acid, glutaric acid, adipic acid, pimelic acid, phthalic acid, azelaic acid, sebacic acid, and their esters with lower alcohols having 1 to 4 carbon atoms such as methanol, ethanol, propanol or butanol, or their isomers, if present. Of those, adipic acid is most preferable from both effectiveness and economical angle.
Examples of acrylic acid or methacrylic acid and its lower alcohol ester having 1 to 4 carbon atoms, of the compound c include, for example, acrylic acid, methacrylic acid, methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, propyl acrylate, propyl methacrylate, butyl acrylate and butyl methacrylate.
The polyamide polyamine comprising three components of the above compounds a, b and c can easily be obtained by the conventional polycondensation technique.
The alkylene oxide having 2 to 4 carbon atoms, which is the compound d, to be added to amino residue of polyamide polyamine is ethylene oxide, propylene oxide or butylene oxide. One or more of alkylene oxides described may be used.
Preparation of the polyamide polyamine, inter alia, polycondensation reaction of the compounds a, b and c, may be two-step reaction comprising polycondensation of only the compound a and the compound b, thereafter further polycondensation with the compound c as a monobasic acid, or one step reaction comprising simultaneous polycondensation with the compounds a, b and c from the start.
However, either method leads to the same polycondesation reaction, that is amidation reaction in which acrylic acid residue or methacrylic acid residue of the compound c are ultimately found at the end of a polyamide chain since the amidation reaction proceeds in parallel to amide interchange reaction.
Following is a reaction molar ratio of the three components constituting the polyamide polyamine described below.
The reaction molar ratio of the compound b (dibasic acid or its ester) to one mole of the compound a (polyalkylene polyamine) is 0.8-0.95 mole. Polycondensation product of the compound a and the compound b in molar ratio defined above produces, on the average, a polyamide with a certain chain length, comprising polycondensation of from (polyalkylene polyamine 5 moles:dibasic acid 4 moles) to (polyalkylene polyam
Amaya Toshihiko
Danzinger Wernher M.
Ikeda Akira
Imamura Jun
Kobayashi Atsushi
Lipman Bernard
Oliff & Berridg,e PLC
Sika Ltd.
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