AU762094B2 - Cement dispersants and method of producing concrete by using same - Google Patents

Description

AUSTRALIA

PATENTS ACT 1990 COMPLETE SPECIFICATION NAME OF APPLICANT(S): Takemoto Yushi Kabushiki Kaisha ADDRESS FOR SERVICE: DAVIES COLLISON CAVE Patent Attorneys 1 Little Collins Street, Melbourne, 3000.

INVENTION TITLE: Cement dispersants and method of producing concrete by using same The following statement is a full description of this invention, including the best method of performing it known to me/us:re Background of the Invention This invention relates to cement dispersants and methods of how to use them to produce better concrete. At work sites where cement compositions are used, it is important to be able to provide high fluidity to 10 cement compositions, to reduce the drop in the provided fluidity with time ("the slump loss") and to obtain a sufficient early strength during the initial period of hardening such that the frames can be removed quickly and the work efficiency can be thereby improved. This invention relates to cement dispersants which can S.:respond to such requirements, as well as methods of using such cement dispersants to produce concrete with improved quality..This invention related also to concrete produced by using such a cement dispersant.

Examples of prior art cement dispersant for providing fluidity to cement compositions include salts of high condensates of naphthalene sulfonic acid formaldehyde and melamine sulfonic acid forialdehyde, as well as watersoluble vinyl copolymers. Cement compositions prepared by using salts of high condensates of naphthalene sulfonic acid formaldehyde or melamine sulfonic acid formaldehyde, however, have the problem of a high slump loss. Those prepared by using water-soluble vinyl copolymers of the conventionally proposed kind (such as disclosed in Japanese Patent Publications Tokko 58-38380, 59-18338 and 5-11057 and U.S. patents 4,962,173, 5,087,648, 5,290,869 and 5,362,829) have smaller slump losses but there are problems wherein their setting times become longer and hence a sufficient early strength cannot be obtained during the early period of hardening. This problem is particularly significant with high-strength cement compositions with a limited water-to-cement ratio.

Summary of the Invention The problem to be overcome by the present invention is that prior art cement dispersants could produce only cement compositions with a large slump loss or incapable of providing a sufficiently large early strength, this problem being particularly significant with high-strength cement compositions with a limited water-to-cement ratio.

The present invention was accomplished as a result of investigations by the present inventors and is based on their discovery that watersoluble vinyl copolymers constituting of specified kinds of constituent units (herein referred to simply as "units") at a specified ratio and having both the 15 weight average molecular weight and the ratios between the weight average molecular weight and the number average molecular weight within a specified range are suitable as a cement dispersant.

Detailed Description of the Invention 9 This invention relates to cement dispersants which are water- 9 soluble vinyl copolymers constituting of 40-80 molar of Unit A shown below by Formula 0.5-20 molar of Unit B shown below by Formula 0.2-18 molar of Unit C shown below by Formula and 2-40 molar of Unit D shown below by Formula such that the total is 100 molar the weight average molecular weight (hereinafter always pullulan converted by GPC method) being 15000-150000 and the ratio of weight average molecular weight to number average molecular weight being 2-7, Formulas being as follows:

R

(CH2-C)

COOM

(Formula 1)

(CH

2

CH

2

X

R

2

(CH

2

COOCH

3 (Formula 2) (Formula 3)

COO-A-OR

4 (Formula 4) a. a a where R 2 and R 3 are each either H or CH 3 R' is H or an alkyl group with 1-3 carbon atoms, X is a group shown below by Formula or -SO3M 2 (Formula -O-CsH 4

-SO

3

M

3 (Formula 6) 25 A is the residual group obtainable by removing all hydroxyl groups from polyether diol with the repetition number of oxyalkylene units (which consist either only of oxyethylene units or of both oxyethylene and oxypropylene units) being 5-109, M' is H, an alkali metal, an alkali earth metal, ammonium or an organic amine, and M 2 and M 3 are each an alkali metal, an alkali earth metal, ammonium or an organic amine.

Cement dispersants of this invention are a water-soluble vinyl copolymers having four constituent units described above but those having as Unit D both Unit E shown below by Formula and Unit F shown below by Formula are preferred:

(CH

2 (Formula 7)

COO(CH

2

CH

2 O) R 6

CH

3

-(CH

2 (Formula 8) COO (CH 2

CH

2 0),,CH 3 where R 5 is H or CH 3

R

6 is an alkyl group with 1-3 carbon atoms, n is an integer 40-109 and m is an integer 5-25. In other words, preferred kinds of watersoluble vinyl copolymers according to this invention include not only Units A, B and C shown by Formulas and but also a relatively long polyoxyethylene graft chain due to Unit E of Formula and a relatively short chain polyoxyethylene graft chain.

These constituent Units A, B, C and D, or Units A, B, C, E and F in the case of an aforementioned preferred example, can all be formed by copolymerizing corresponding vinyl monomers. Examples of vinyl monomers 20 which form Unit A shown by Formula include (meth)acrylic acid, and (2) alkali metal salts, alkali earth metal salts and organic amine salts of(meth)acrylic acid. Of these, alkali metal salts such as sodium and potassium salts of S(meth)acrylic acid are preferred.

Examples of vinyl monomers which form Unit B shown by 25 Formula include alkali metal salts, alkali earth metal salts and organic amine salts of methallyl sulfonic acid, and alkali metal salts, alkali earth metal salts and organic amine salts ofp-methallyl oxybenzene sulfonic acid. Of these, alkali metal salts such as sodium and potassium salts of methallyl sulfonic acid are preferred.

Examples of vinyl monomers which form Unit C shown by Formula include methyl acrylate and methyl methacrylate. Of these, methyl acrylate is preferred.

Examples of vinyl monomers which form Unit D shown by Formula include alkoxy polyoxyalkylene glycol (meth)acrylate with 1-3 carbon atoms and (2) polyoxyalkylene glycol mono(meth)acrylate, both with repetition number of oxyalkylene units 5-109. Examples of(1) above include methoxy polyethylene glycol (meth)acrylate, methoxy polyethylene glycol polypropylene glycol (meth)acrylate, methoxy polypropylene glycol (meth)acrylate, ethoxy polyethylene glycol (meth)acrylate, ethoxy polyethylene glycol polypropylene glycol (meth)acrylate, ethoxy polypropylene glycol (meth)acrylate, n-propoxy polyethylene glycol (meth)acrylate, n-propoxy polyethylene glycol polypropylene glycol (meth)acrylate, isopropoxy polyethylene glycol mono(meth)acrylate, and isopropoxy polyethylene glycol polypropylene glycol (meth)acrylate. Examples of above include polyoxyalkylene glycol mono(meth)acrylates such as polyethylene glycol mono(meth)acrylate, polyethylene glycol polypropylene 15 glycol mono(meth)acrylate, and polypropylene glycol mono(meth)acrylate. Of these, methoxy polyethylene glycol methacrylate and polyethylene glycol monomethacrylate with oxyalkylene units including only oxyethylene units and their repetition number in the range of 26-95 are preferred.

Examples of vinyl monomers which form Unit E shown by 20 Formula include alkoxy polyethoxyethyl (meth)acrylates with 1-3 carbon atoms and the repetition number of oxyethylene units in the range of 40-109 such as methoxy polyethoxyethyl (meth)acrylate, ethoxypolyethoxyethyl (meth)acrylate, n-propoxy polyethoxyethyl (meth)acrylate, and isopropoxy polyethoxyethyl (meth)acrylate. Of these, methoxy polyethoxyethyl 25 methacrylates with the repetition number of oxyethylene units in the range of 100 are preferred.

Examples of vinyl monomers which form Unit F shown by Formula include methoxy polyethoxyethyl methacrylates with the repetition number of oxyethylene units in the range of 5-25. Of these, methoxy polyethoxyethyl methacrylates with the repetition number of oxyethylene units in the range of 7-23 are preferred.

Water-soluble vinyl copolymers to be used as a cement dispersant according to this invention may be obtained by radical copolymerization of vinyl monomers forming Units A-D, or preferably Units A, B, C, E and F at a specified copolymerization ratio in the presence of a radical initiator. The radical copolymerization can be carried out by aqueous solution polymerization using water or a mixed solvent with water and a water-soluble organic solvent either continuously or by batches. For example, each of the vinyl monomers is initially dissolved in water to prepare an aqueous solution with pH 4.5-6.5 containing these vinyl monomers by 10-40 weight as their total. Next, a radical initiator is added to this aqueous solution within a nitrogen gas atmosphere to carry out a radical copolymerization reaction at 50-70°C for 5-8 hours and to thereby obtain water-soluble vinyl copolymer. Any radical initiator which generates radicals by 15 decomposing at the reaction temperature of copolymerization may be used for the copolymerization reaction of either of the vinyl monomers, but the use of a water-soluble radical initiator is preferred. Examples of such water-soluble radical initiator include persulfates such as potassium persulfate and ammonium persulfate, hydrogen peroxide, and 2,2-azobis (2-amidinopropane) 20 dihydrochloride. They may be combined with a reducing agent such as a sulfite and L-ascorbic acid or amines to be used as a redox initiator.

As described above, water-soluble vinyl copolymers to be used as a cement dispersant according to this invention are characterized as comprising Units A-D, or preferably Units A, B, C, E and F at a specified ratio, but they are 25 also required to have the weight average molecular weight (pullulan converted by GPC method) and the ratio of weight average molecular weight to number average molecular weight (hereinafter denoted as Mw/Mn) within specified ranges. Adjustment of such molecular weight distributions can be effected by a conventional method of appropriately controlling concentrations of the vinyl monomers in the system for radical copolymerization, the pH of the polymerizing 7 system, its temperature and the addition of a chain transfer agent. In order to obtain a water-soluble vinyl copolymer with a desired molecular weight distribution, it is preferred to set the pH value of the polymerizing system at and to add a chain transfer agent such as 2-mercapto ethanol, 2 -mercapto propionic acid, 3-mercapto propionic acid, thioglycol acid and thioglycerine to the polymerizing system. Since vinyl monomers forming Unit B function as a themselves, this property may be appropriately taken advantage of.

The water-soluble vinyl copolymers constituting of Units A-D, to be used as a cement dispersant according to this invention, contain Unit A by 80 molar or preferably by 55-72 molar Unit B by 0.5-20 molar or preferably 3-18 molar Unit C by 0.2-18 molar or preferably 3-15 molar and Unit D by 2-40 molar or preferably 3-30 molar (such that the total is 100 molar Those constituting of Units A, B, C, E and F contain Unit A by 40-80 molar or preferably 55-72 molar Unit B by 0.5-20 molar or 15 preferably 3-18 molar Unit C by 0.2-18 molar or preferably 3-15 molar Unit E by 2-15 molar or preferably 3-12 molar and Unit F by 0.5-15 molar or preferably 1-12 molar (such that the total is 100 molar The water-soluble vinyl copolymers to be used as a cement dispersant according to this invention are further characterized in that their weight average molecular weight be 15000-150000 or preferably 25000-70000 and that their ratio Mw/Mn be 2-7 or preferably 3-6.5.

For preparing cement compositions by using a cement dispersant of this invention, different kinds of agents may be used together, depending of the purpose. Examples of such agents include air entraining agents, antifoaming agents, waterproofing agents, hardening accelerators and antiseptics. They may be added with kneading water when the cement composition is prepared or after the cement composition has been mixed and kneaded.

Cement dispersants of this invention can be used for cement compositions such as mortars and concrete prepared by using a binder composed of cement or a mixture of cement and a microscopic powder admixture.

Examples of cement which can be used include many kinds of portland cement such as ordinary portland cement, high early strength portland cement and moderate heat portland cement, blast furnace cement, fly ash cement, silica fume cement as well as many other kinds of blended cement. Examples of microscopic powder admixture include silica fume, blast-furnace slag and fly ash. Cement dispersants of this invention are normally mixed at a ratio of 0.05-2.0 weight parts, or preferably 0.1-1.5 weight parts, as converted to solid component per 100 weight parts of the binder comprised of cement or a mixture of cement and a microscopic powder admixture.

As explained above, water-soluble vinyl copolymers to be used as a cement dispersant according to this invention are characterized not only as constituting of Units A-D, or preferably Units A, B, C, E and F, at a specified ratio, but also as having weight average molecular weight and Mw/Mn within specified ranges. Those constituting of Units A, B, C, E and F are particularly characterized as containing in the molecule both a relatively long polyoxyethylene graft chain and a relatively short polyoxyethylene graft chain. Cement dispersants of this invention with such particular characteristic are effective not only when used with ordinary cement compositions with the water/cement ratio in excess of 45% but also with cement compositions with the water/cement ratio 20-45% such as concrete. They can provide high fluidity even to high-strength concrete with the water/cement ratio limited to 20-45%, reduce the slump loss, limit the setting time delay and realize a sufficient early strength.

The invention is described next by way of the following thirteen embodiments.

S* 25 Embodiment (1) Cement dispersant using water-soluble vinyl copolymer with sodium methacrylate as Unit A by 63 molar sodium methallyl sulfonate as Unit B by 15 molar methyl acrylate as Unit C by 8 molar and methoxy glycol monomethacrylate (the repetition number of oxyethylene units being indicated hereinafter by as Unit D by 14 molar (such that the total is 100 molar of which the weight average molecular weight is 42500 and Mw/Mn 4.6.

Embodiment (2) Cement dispersant using water-soluble vinyl copolymer with sodium methacrylate as Unit A by 67 molar sodium methallyl sulfonate as Unit B by 15 molar methyl acrylate as Unit C by 11 molar and methoxy poly(p=68)ethylene glycol monomethacrylate as Unit D by 7 molar (the total being 100 molar of which the weight average molecular weight is 46000 and Mw/Mn 4.8.

Embodiment (3) Cement dispersant using water-soluble vinyl copolymer with sodium methacrylate as Unit A by 72 molar sodium methallyl sulfonate as Unit B by 9 molar methyl acrylate as Unit C by 14 molar and methoxy 15 poly(p=90)ethylene glycol monomethacrylate as Unit D by 5 molar (the total being 100 molar of which the weight average molecular weight is 59000 and Mw/Mn 5.7.

Embodiment (4) Cement dispersant using water-soluble vinyl copolymer with 20 sodium methacrylate as Unit A by 60 molar sodium methallyl sulfonate as Unit B by 5 molar methyl acrylate as Unit C by 10 molar and methoxy glycol monomethacrylate as Unit D by 25 molar (the total being 100 molar of which the weight average molecular weight 40700 is and Mw/Mn 4.3.

Embodiment Cement dispersant using water-soluble vinyl copolymer with sodium acrylate as Unit A by 55 molar sodium p-methallyl oxybenzene sulfonate as Unit B by 15 molar methyl acrylate as Unit C by 3 molar and methoxy poly(p=45)ethylene glycol monomethacrylate as Unit D by 27 molar (the total being 100 molar of which the weight average molecular weight is 51500 and Mw/Mn 3.2.

Embodiment (6) Cement dispersant using water-soluble vinyl copolymer with sodium methacrylate as Unit A by 62 molar sodium p-methallyl oxybenzene sulfonate as Unit B by 12 molar methyl acrylate as Unit C by 6 molar and methoxy poly(p=45)ethylene glycol monomethacrylate as Unit D by 20 molar (the total being 100 molar of which the weight average molecular weight is .38700 and Mw/Mn 15 Embodiment (7) Cement dispersant using water-soluble vinyl copolymer with sodium methacrylate as Unit A by 70 molar sodium methallyl sulfonate as Unit B by 14 molar methyl acrylate as Unit C by 10 molar and polyethylene glycol (p=90) monomethacrylate as Unit D by 6 molar (the total being 100 molar of which the weight average molecular weight is 54800 and Mw/Mn 5.1.

Embodiment (8) Cement dispersant using water-soluble vinyl copolymer with sodium methacrylate as Unit A by 62 molar sodium methallyl sulfonate as Unit B by 12 molar methyl acrylate as Unit C by 12 molar methoxypolyethoxyethyl (n in Formula 68) methacrylate as Unit E by 8 molar and methoxypolyethoxyethyl (m in Formula 9) methacrylate as Unit F by 6 molar (the total being 100 molar of which the weight average molecular weight is 66600 and Mw/Mn Embodiment (9) Cement dispersant using water-soluble vinyl copolymer with sodium methacrylate as Unit A by 57 molar sodium methallyl sulfonate as Unit B by 15 molar methyl acrylate as Unit C by 14 molar methoxypolyethoxyethyl (n in Formula 68) methacrylate as Unit E by molar and methoxypolyethoxyethyl (m in Formula 23) methacrylate as Unit F by 2 molar (the total being 100 molar of which the weight average molecular weight is 38500 and Mw/Mn Embodiment Cement dispersant using water-soluble vinyl copolymer with sodium methacrylate as Unit A by 72 molar sodium methallyl sulfonate as Unit B by 8 molar methyl acrylate as Unit C by 5 molar 15 methoxypolyethoxyethyl (n in Formula 95) methacrylate as Unit E by 4 molar and methoxypolyethoxyethyl (m in Formula 9) methacrylate as Unit F by 11 molar (the total being 100 molar of which the weight average molecular weight is 62900 and Mw/Mn 3.4.

Embodiment (11) 20 Cement dispersant using water-soluble vinyl copolymer with sodium methacrylate as Unit A by 65 molar sodium methallyl sulfonate as Unit B by 5 molar methyl acrylate as Unit C by 10 molar methoxypolyethoxyethyl (n in Formula 45) methacrylate as Unit E by 12 molar and methoxypolyethoxyethyl (m in Formula 23) methacrylate as Unit F by 8 molar (the total being 100 molar of which the weight average molecular weight is 114700 and Mw/Mn 3.1.

Embodiment (12) Cement dispersant using water-soluble vinyl copolymer with sodium acrylate as Unit A by 70 molar sodium p-methallyl oxybenzene sulfonate as Unit B by 10 molar methyl acrylate as Unit C by 6 molar isopropoxypolyethoxyethyl (n in Formula 55) acrylate as Unit E by 11 molar and methoxypolyethoxyethyl (m in Formula 9) methacrylate as Unit F by 3 molar (the total being 100 molar of which the weight average molecular weight is 89700 and Mw/Mn 3.9.

Embodiment (13) Cement dispersant using water-soluble vinyl copolymer with sodium methacrylate as Unit A by 58 molar sodium p-methallyl oxybenzene sulfonate as Unit B by 18 molar methyl acrylate as Unit C by 8 molar methoxypolyethoxyethyl (n in Formula 68) methacrylate as Unit E by molar and methoxypolyethoxyethyl (m in Formula 23) methacrylate as .o 15 Unit F by 6 molar (the total being 100 molar of which the weight average molecular weight is 51000 and Mw/Mn Examples The invention will be described next by way of examples but these examples are not intended to limit the scope of the invention. In what follows, "parts" shall mean "weight parts" and shall mean "weight excluding the weight of air", unless otherwise noted.

a.

Part 1 (Synthesis of water-soluble vinyl copolymers) Synthesis of Test Example 1 Methacrylic acid 103 parts (1.20 moles), sodium methallyl sulfonate 47 parts (0.29 moles), methyl acrylate 13 parts (0.15 moles), glycol monomethacrylate 559 parts (0.27 moles) and water 1500 parts were placed inside a reactor vessel, and after a 30% water solution of sodium hydroxide 90 parts was added to adjust the pH and to obtain a uniform solution, the atmosphere was replaced with nitrogen gas. The pH of the reacting system was 5.8. The temperature of the reacting system was maintained at 60°C by means of a temperature bath and a polymerization process was started by adding a 20% water solution of sodium persulfate 30 parts by titration over 3 hours. The polymerization process was continued for 2 hours more to conclude the polymerization. Thereafter, a 30% water solution of sodium hydroxide 10 parts was added for complete neutralization to obtain a reaction product. After a portion of the product thus obtained was condensed inside an evaporator, it was precipitated and refined inside a mixed acetone/isopropanol solvent and dried to obtain water-soluble vinyl copolymer (Test Example This water-soluble vinyl copolymer (Test Example 1) was analyzed by NMR, elemental analysis, titration method and GPC and was found to be a water-soluble vinyl copolymer having sodium methacrylate as Unit A by 63 molar sodium methallyl sulfonate as Unit B by 15 molar methyl acrylate as Unit C by 8 molar and methoxypoly(p=45)ethylene glycol monomethacrylate as Unit D by 14 molar (the total being 100 weight of which the weight average molecular weight was 42500 and Mw/Mn 4.6.

Synthesis of Test Example 2 Methacrylic acid 153 parts (1.57 moles), sodium methallyl sulfonate 63 parts (0.40 moles), methyl acrylate 23 parts (0.27 moles), methoxypoly(p=68)ethylene glycol monomethacrylate 560 parts (0.18 moles) and water 1600 parts were placed inside a reactor vessel, and after a 30% water solution of sodium hydroxide 147 parts was added to adjust the pH and to obtain 25 a uniform solution, the atmosphere was replaced with nitrogen gas. The pH was of the reacting system was 5.5. The temperature of the reacting system was maintained at 60 0 C by means of a temperature bath and a polymerization process was started by adding a 20% water solution of sodium persulfate 40 parts by titration over 3 hours. The polymerization process was continued for 3 hours more to conclude the polymerization. Thereafter, a 30% water solution of sodium hydroxide 63 parts was added for complete neutralization to obtain a reaction product. After a portion of the product thus obtained was condensed inside an evaporator, it was refined and dried by using a mixed solvent to obtain water-soluble vinyl copolymer (Test Example This water-soluble vinyl copolymer (Test Example 2) was analyzed by NMR, elemental analysis, titration method and GPC and was found to be a water-soluble vinyl copolymer having sodium methacrylate as Unit A by 67 molar sodium methallyl sulfonate as Unit B by 15 molar methyl acrylate as Unit C by 11 molar and methoxypoly(p=68)ethylene glycol monomethacrylate as Unit D by 7 molar (the total being 100 weight of which the weight average molecular weight was 46000 and Mw/Mn 4.8.

Synthesis of Test Examples 3-13 Water-soluble vinyl copolymers (Test Examples 3-13) were S15 similarly obtained as explained above for the production of Test Examples 1 and 2. Their compositions are shown in Table 1.

Synthesis of Comparison Example 1 Methacrylic acid 103 parts (1.20 moles), sodium methallyl sulfonate 14 parts (0.086 moles), methoxypoly(p=45)ethylene glycol monomethacrylate 891 20 parts (0.428 moles) and water 2100 parts were placed inside a reactor vessel, and after a 30% water solution of sodium hydroxide 160 parts was added to adjust

S

the pH and to obtain a uniform solution, the atmosphere was replaced with nitrogen gas. The pH was of the reacting system was 9.2. The temperature of the reacting system was maintained at 60°C by means of a temperature bath and a polymerization process was started by adding a 20% water solution of sodium persulfate 50 parts by titration over 3 hours to obtain a reaction product. After a portion of the product thus obtained was condensed inside an evaporator, it was refined and dried by using a mixed solvent to obtain water-soluble vinyl copolymer (Comparison Example This water-soluble vinyl copolymer (Comparison Example 1) was analyzed similarly as explained above and was found to be a water-soluble vinyl copolymer having sodium methacrylate as Unit A by 70 molar sodium methallyl sulfonate as Unit B by 5 molar and glycol monomethacrylate as Unit D by 25 molar (the total being 100 weight of which the weight average molecular weight was 62500 and Mw/Mn 8.3.

Synthesis of Comparison Examples 2-15 Water-soluble vinyl copolymers (Comparison Examples 2-15) were similarly obtained as explained above for the production of Comparison Example 1. Their compositions are shown in Table 2.

Table 1 Kinds and molar of constituent Units WAMW Mw/Mn Unit A Unit B Unit C Unit D Unit E Unit F 0* Test Example: 1 A-1 63 2 A-I 67 3 A-I 72 4 A-1 60 5 A-2 55 6 A-I 62 7 A-I 70 8 A-I 62 9 A-1 57 10 A-I 72 11 A-1 65 12 A-2 70 13 A-3 58 D-1

D-:

D-

D-

D-

D-

D-

14 2 7 3 5 1 25 1 27 1 20 4 6

E

E-

E

E

42500 46000 59000 S40700 51500 38700 S54800 -1 8 F-1 6 66600 -1 10 F-2 2 38500 -2 4 F-1 11 62900 -3 12 F-2 8 114700 -4 11 F-1 3 89700 -1 10 F-2 6 51000 In Table I and thereafter: WAMW: Weight average molecular weight Table 2 Kinds and molar of constituent Units WAMW Mw/Mn Unit A Unit B Unit C Unit D Unit E Unit F Others Comparison Example: 1 A- 170 B-I 5 D-1 25 2 A-i1 73 D-1 27 3 A-1 65 C-lb1 D-1 25 4 A-I SO5 B-I 25 C-i 5 D-1 20 A-i1 65 B-i 8 C-i 7 D-2 20 6 A-i1 70 B-2 0.3 C-I 6.7 D-3 23.

7 A-I 60 B-2 18 C-i 10 D-1 12 8 A- 176 B-1 15C-1 5 9 A-i1SO B-I 5SC-i S5 A-i 45 B-I 3 C-i 2 D-I 50 11 A-I 63 C-i 8 D-1 14 12 A-2 48 B-2i10 C-i 7 13 A-i 60 B-2i10 C-i i10 i4 A-i 65 C-i 5 A-i 65 B-1 O C-i S5 62500 51000 118000 9800 76000 127000 31000 X-I 4 89000 X-2 40 22500 72600 X-3 15 38000 X-4 3S5 55700 -3 5 F-i 5 X-3 10 10000 -i 10 F-i 10 X-3 10 69300 -2 10 X-4 10 124000 8.3 5.8 12.5 8.7 6.8 1.8 4.7 6.3 4.2 5.9 3.2 3.1

E

E

E

S

S

In Tables I and 2: A-i1: Unit of sodium methacrylate A-2: Unit of sodium acrylate A-3: Unit of methacrylic acid B-1: Unit of sodium rnethallyl sulfonate B-2: Unit of sodium p-i-ethallyl oxybenzene sulfonate C- 1 Unit of methyl acrylate D-l1: Unit of methoxy poly(p=45)ethylene glycol methacrylate D-2: Unit of rnethoxy poly(p=68)ethylene glycol mnethacrylate D-3: Unit of methoxy poly(p=90)ethylene glycoi methacrylate D-4: Unit of polyethylene glycol (p=90) monomnethacrylate Unit of methoxypolyethoxyethyl (n in Formula =68) 35 methacrylate E-2: Unit of methoxypolyethoxyethyl (n in Formula 95) methacrylate Unit of rmethoxypolyethoxyethyl (n in Formula rnethacryl ate E-4: Unit of isopropoxy polyethoxyethyl (n in Formula 55) acrylate F-I1: Unit of i-ethoxypolyethoxyethyl (m in Formula 9) mnethacrylate F-2: Unit of methoxypolyethoxyethyl (m in Formula 23) methacrylate X- i: Unit of methoxypoly(p= 1 5O)ethylene glycol mnethacrylate X-2: Unit of m-ethoxypoly(p=3))ethylene glycol niethacrylate X-3 Unit of sodium styrene Sul1foniate X-4: Unit of 2-hydroxyethyl m-ethacrylate 17 Part 2 (Preparation and Evaluation of Concrete) Preparation of Concrete Each of the test examples of concrete was prepared by placing ordinary portland cement (specific weight=3.16, Braine value=3300), fine aggregates (sand from Ooi River with specific weight=2.63) and coarse aggregates (crushed stone from Okazaki with specific weight=2.66) sequentially into a 50-liter pan-type forced kneading mixer under the conditions shown in Table 3 and kneaded for 15 seconds. Next, the cement dispersants prepared in Part 1 were added together with kneading water at a rate of 0.1-1.5 weight with respect to the cement converted to solid components such that the target slump value would be within the range of21 ±lcm and the mixture was kneaded for 2 minutes. An agent for controlling the amount of air was kneaded in with water in each case such that the target air content would become 4.0-5.0%.

Table 3 a..

a a a. a Condition of Water/ Sand- Used materials (kg/m 3 Preparation Cement Coarse Ratio Aggregate Ratio Water Cement Fine Coarse aggregate aggregate 1 33 44 165 500 742 944 2 50 49 165 330 867 960 Evaluation of Concrete For each of test and comparison examples, slump value air quantity setting time and compression strength were measured according respectively to JIS-A 1101, JIS-A 1128, JIS-A6204 and JIS-Al 108 immediately after the kneading 60 minutes later (t=60) and 90 minutes later The results are shown in Tables 4-7. In these Tables, the numbers in parentheses following the test and comparison example numbers indicate the condition of preparation defined in Table 3. Slump ratio is defined as the percentage ratio of the slump value after minutes to the slump value immediately after the kneading.

These tables clearly show that cement dispersants according to this invention can provide a high level of fluidity while limiting the slump loss, as well as a high early strength at the initial period of hardening.

Table 4 Test Cement t=0 t=60 t=90 Slump No. dispersant Ratio Kind Amount SV AQ SV AQ SV AQ (Part)(*l) (cm) (cm) (cm) Test Examples ooeo oo o oooo o o o 9 o oo oo 1(1) 2(1) 3(1) 4(1) 5(1) 6(1) 7(1) 1(2) 2(2) 3(2) 4(2) 5(2) 6(2) 7(2) 8(1) 9(1) 10(1) 11(1) 12(1) 13(1) 8(2) 9(2) 10(2) 11(2) 12(2) 13(2) 0.22 0.20 0.22 0.27 0.34 0.28 0.21 0.19 0.18 0.20 0.24 0.30 0.24 0.19 0.18 0.17 0.21 0.26 0.24 0.16 0.15 0.14 0.22 0.25 0.23 0.19 21.5 21.7 21.8 21.5 21.3 21.5 21.2 21.4 21.5 21.7 21.4 21.8 21.4 21.6 21.7 21.5 21.4 21.6 21.3 21.6 21.5 21.8 21.6 21.3 21.7 21.5 20.4 20.7 20.2 21.0 19.9 20.6 19.6 20.3 20.7 20.1 20.3 20.1 20.7 20.0 20.5 21.0 20.9 20.8 20.4 20.5 20.7 21.0 21.1 20.4 20.3 20.6 19.6 19.8 19.4 19.9 18.7 19.5 18.4 19.9 19.4 18.8 19.5 18.7 19.3 18.6 20.2 19.8 20.4 20.1 19.7 19.9 19.4 19.9 20.2 19.5 19.7 19.4 4.4 4.5 4.2 4.0 4.1 4.0 4.2 4.3 4.4 4.3 4.5 4.3 4.3 4.2 4.3 4.3 4.4 4.2 4.1 4.0 4.2 4.2 4.3 4.4 4.3 4.2 91.1 91.2 89.0 92.5 87.8 90.7 86.8 89.2 90.2 86.6 91.1 85.8 90.2 86.1 93.1 92.1 95.3 93.1 92.5 91.7 90.2 91.3 92.5 91.5 90.8 90.2 The amount of cement dispersant is shown as converted to solid components with respect to 100 parts of cement.

Condition No. for preparation of concrete Table Test Cement t=0 t=60 t=90 Slump No. dispersant Ratio

(O)

Kind Amount SV AQ SV AQ SV AQ (Part)(* 1) (cm) (cm) (cm) Comparison Examples 1(1) 0.280 2(1) 0.30 3(1) 0.55 4(1) 0.45 5(1) 0.29 6(1) 0.60 7(1) 0.35 8(1) 0.43 9(1) 0.31 10(1) 0.95 11(1) 0.49 12(1) 0.47 1(2) 0.27 2(2) 0.29 3(2) 0.48 4(2) 0.42 5(2) 0.27 6(2) 0.58 7(2) 0.32 8(2) 0.40 9(2) 0.30 10(2) 0.90 11(2) 0.45 12(2) 0.42 13(1) 0.47 14(1) 0.36 15(1) 0.58 13(2) 0.53 14(2) 0.34 15(2) 0.50 0.76 21.5 21.7 21.2 21.3 21.6 21.2 21.4 21.6 21.3 21.2 21.7 21.4 21.6 21.3 21.5 21.8 21.4 21.7 21.5 21.4 21.6 21.7 21.9 21.3 21.8 21.5 21.3 21.6 21.2 21.5 21.7 17.1 4.4 16.0 4.5 15.0 4.3 17.7 4.1 17.3 4.4 16.4 4.6 15.0 4.5 13.8 4.6 15.5 4.6 14.5 4.6 15.2 4.6 15.7 4.4 15.7 4.4 15.0 4.3 17.0 4.6 17.2 4.4 16.9 4.5 13.5 4.4 12.8 4.5 12.0 4.7 16.2 4.4 12.1 4.5 12.8 4.5 13.0 4.4 15.2 4.4 14.4 4.3 16.0 4.4 12.8 4.5 12.3 4.6 16.7 4.5 11.2 4.2 13.4 4.4 12.1 4.2 11.8 4.0 15.2 4.1 14.6 4.2 12.9 4.2 10.8 4.1 9.2 4.4 12.5 4.4 10.7 4.3 11.8 4.5 12.0 4.1 13.3 4.2 10.1 4.1 15.0 4.5 15.6 4.3 13.9 4.5 11.2 4.2 10.4 4.4 9.2 4.2 13.0 4.4 9.1 4.4 12.2 4.3 11.4 4.1 11.0 4.1 10.3 4.3 13.2 4.4 10.4 4.3 9.7 4.4 13.2 4.3 9.0 4.0 64.5 57.9 72.4 76.7 70.8 60.7 50.5 47.9 62.0 45.0 54.3 56.1 61.6 47.4 69.8 71.6 65.0 51.6 48.4 43.0 60.2 41.9 41.4 53.5 50.5 47.9 62.0 48.1 45.8 61.4 41.4 The amount of cement dispersant is shown as converted to solid components with respect to 100 parts of cement.

Salt of high condensates of naphthalene sulfonic acid formaldehyde (Polefine 510-AN, tradename of Takemoto Yushi Kabushiki Kaisha) Condition No. for preparation of concrete 6 Test Setting Time Compressive Strength (N/mm 2 N o m m i l 1 h 1 4 2 i Start End Time Time Time Time Time 335 320 300 340 355 330 305 340 320 315 355 360 330 -310 310 300 330 335 330 30 5 -320 310 355 360 350 335 415 400 370 435 450 410 365 420 405 395 455 465 425 390 385 375 405 420 410 390 410 395 450 460 445 420 9.7 10.1 12.0 9.0 8.8 9.8 12.5 3.5 3.7 3.9 3. 3 3.2 .3.5 4.0 10.2 12.0 9.6 9.3 9.5 11.8 3.7 3.9 3.4 3.4 3.6 3.5 22.2 22.5 24.0 21.3 21.0 22.0 24.5 6.7 6.9 7.0 6.5 6.3 6.7 7.0 22.5 24.0 22.0 21.7 22.1 24.0 6.8 7.0 6.5 6.6 6.5 6.6 36.5 38.8 43.0 36.0 35.7 39.0 44.0 16.6 16.7 16.9 16.2 16.0 16.8 17.0 38.6 43.5 36.2 35.7 36.0 43.6 16.6 16.8 16.4 16.5 16.7 16.6 53.7 54.0 55.6 53.5 53.0 54.3 55.8 26.8 27.1 27.3 26.4 26.2 27.0 27.4 53.8 55.7 54.0 53.0 5 3. 1 55.6 26.9 27.2 26.5 .26.5 26.6 26.7 .g 25 4. 7 Test No.

Setting Time Compressive Strength (N/mm 2 1 1- Start (rlinl) End (ini) Time (811) Time (1211) Time (1 811) Ti me (24h) r 1 1- 1- .1.

27 380 28 410 29 470 4 30 31 380 32 500 33 425 34 450 480 36 650 37 4410 38 495 39 405 420 41 510 42 450 43 400 44 535 445 46 480 47 460 '18 620 49 490 50 540 51 530 52 455 53 550 54 540 465 56 530 57 360 490 530 590 550 485 620 540 580 605 780 575 590 540 560 .645 *590 53 5 690 585 620 600 785 635 680 675 590 695 690 600 670 445 1.2.

.0,7 0.1 0.2 1.7 0.5.

0.2 *3 *3 *3 0.2 *3 0.2 *3 0.3 *3 3 9.6 9.0 2.9 4.2 11.1 1.8 4.3 2.9 2.5 *3 0.4A 0.2 3.1 1.8 *3 3.5 *3 0.2 *3 *3 *3 06.9 14.8 13.5 6.6 7.7 17.0 6.4 8.0 7.0 6.5 1.5 -7.0 3.1 8.5 7.5 2.7 2.0 10.0 0.4 3.6 30 1.9 3 0.8 3.6 6.3 2.5 0.3 1.9 0.5 28,9 Time (72h) 45.7 43.7 42.5 43.0 47.7 42.3 44.5 43.9 42 .8 41.0 43.8 43.0 22.0 21.6 19.7 20.2 23.4 18.5 21.2 20.7 20.6 15.7 19.5 17.6 39.5 41.5 35.5 18.5 19.0 19.8 51.7 35 3. No measurement Could be taken because there was no hardening.

Claims (9)

1. A cement dispersant constituting of water-soluble vinyl copolymers including 40-80 molar of Unit A shown below by Formula 0.5-20 molar of Unit B shown below by Formula 0.2-18 molar of Unit C shown below by Formula and 2-40 molar of Unit D shown below by Formula total content of said Units A, B, C and D being 100 molar said water-soluble vinyl copolymers having weight average molecular weight pullulan converted by GPC method 15000- 150000 and ratio of weight average molecular weight to number average molecular weight 2-7, Formulas being given by: -(CH 2 COOM CH 3 CH 2 X (Formula 1) (Formula 2) (Formula 3) COOCH R 3 COO-A-OR' S. (Formula 4) where R 2 and R 3 are each H or CH 3 R 4 is H or an alkyl group with 1-3 carbon atoms, X is a group shown below by Formula or -S0 3 M (Formula -O-C 6 H,-SO 3 M 3 (Formula 6) A is a residual group obtainable by removing all hydroxyl groups from polyether diol with repetition number of oxyalkylene units 5-109, said oxyalkylene units consisting either only ofoxyethylene units or of both oxyethylene and oxypropylene units, M' is H, an alkali metal, an alkali earth metal, ammonium or an organic amine, and M 2 and M 3 are each an alkali metal, an alkali earth metal, ammonium or an organic amine.

2. The cement dispersant of claim 1 wherein said UnitD consists of Unit E shown below by Formula and Unit F shown below by Formula said water- soluble vinyl copolymers containing said Unit E by 2-15 molar and said Unit F by 0.5-15 molar R (Formula 7) COO (CH2CH20) nR 6 S10 CH 3 (CH 2 (Formula 8) COO (CH 2 CH20),,CH 3 where R' is H or CH 3 R' is an alkyl group with 1-3 carbon atoms, n is an integer 109 and m is an integer 5-25.

3. The cement dispersant of claim 2 wherein said water-soluble vinyl copolymers contain said Unit A by 55-72 molar said Unit B by 3-18 molar said Unit C by 3-15 molar said Unit E by 3-12 molar and said Unit F by 1-12 molar

4. The cement dispersant of claim 1 wherein said water-soluble vinyl copolymers have weight average molecular weight pullulan converted by GPC method 25000-70000 and ratio of weight average molecular weight to number average molecular weight 3-6.5. The cement dispersant of claim 2 wherein said water-soluble vinyl copolymers have weight average molecular weight pullulan converted by GPC method 25000-70000 and ratio of weight average molecular weight to number average molecular weight 3-6.5.

6. The cement dispersant of claim 3 wherein said water-soluble vinyl copolymers have weight average molecular weight pullulan converted by GPC method 25000-70000 and ratio of weight average molecular weight to number average molecular weight 3-6.5.

7. A method of producing concrete, said method comprising the step of mixing cement, aggregates, a cement dispersant and water such that concrete with water-to-cement ratio of 20-45% is produced, said cement dispersant consisting of water-soluble vinyl copolymers including 40-80 molar of Unit A shown below by 5 Formula 0.5-20 molar of Unit B shown below by Formula 0.2-18 molar of Unit C shown below by Formula and 2-40 molar of Unit D shown below by Formula total content of said Units A, B, C and D being 100 molar said water-soluble vinyl copolymers having weight average molecular weight pullulan converted by GPC method 15000-150000 and ratio of weight average molecular weight to number average molecular weight 2-7, Formulas being given by: (Formula 1) 15 COOM 1 CH, (Formula 2) CH 2 X R 2 (CH 2 (Formula 3) COOCH 3 R 3 (CH2-C) (Formula 4) COO-A-OR 4 where R 2 and R 3 are each H or CH 3 R 4 is H or an alkyl group with 1-3 carbon atoms, X is a group shown below by Formula or -SO3M' (Formula -O-CH4-SO 3 M 3 (Formula 6) A is a residual group obtainable by removing all hydroxyl groups from polyether diol with repetition number ofoxyalkylene units 5-109, said oxyalkylene units consisting either only ofoxyethylene units or of both oxyethylene and oxypropylene units, M' is H, an alkali metal, an alkali earth metal, ammonium or an organic amine, and M 2 and M 3 are each an alkali metal, an alkali earth metal, ammonium or an organic 40 amine.

8. The method of claim 7 wherein said Unit D consists of UnitE shown below by Formula and Unit F shown below by Formula said water-soluble vinyl copolymers containing said Unit E by 2-15 molar and said Unit F by 0.5-15 molar 5 R (CH-C) (Formula 7) COO (CHCH R" CH, (CH-C) (Formula 8) COO (CHCH,0) ,CH 3 where R 5 is H or CH 3 R 6 is an alkyl group with 1-3 carbon atoms, n is an integer 109 and m is an integer 5-25.

9. The method of claim 8 wherein said water-soluble vinyl copolymers contain said Unit A by 55-72 molar said Unit B by 3-18 molar said Unit C by 3-15 molar said Unit E by 3-12 molar and said Unit F by 1-12 molar The method of claim 7 wherein said water-soluble vinyl copolymers have weight average molecular weight pullulan converted by GPC method 25000- 70000 and ratio of weight average molecular weight to number average molecular weight 3-6.5.

11. The method of claim 8 wherein said water-soluble vinyl copolymers have weight average molecular weight pullulan converted by GPC method 25000- 70000 and ratio of weight average molecular weight to number average molecular weight 3-6.5. 2. The method of claim 9 wherein said water-soluble vinyl copolymers have weight average molecular weight pullulan converted by GPC method 25000- 70000 and ratio of weight average molecular weight to number average molecular weight 3-6.5. Dated this 2 7 th day of March, 2003 o Takemoto Yushi Kabushiki Kaisha By Its Patent Attorneys DAVIES COLLISON CAVE o*oooo