Polymers containing carboxyl groups and polyalkylene ether...

Details Polymers containing carboxyl groups and polyalkylene ether... Polymers containing carboxyl groups and polyalkylene ether...

1999-06-21

2002-05-07

Wu, David W. (Department: 1713)

Synthetic resins or natural rubbers -- part of the class 520 ser

Synthetic resins

Processes of preparing a desired or intentional composition...

C524S414000, C524S417000, C524S555000, C524S556000, C524S558000, C526S193000, C526S233000, C526S304000, C526S307400, C526S318410, C526S318500, C526S320000

Reexamination Certificate

active

06384111

ABSTRACT:

The present invention relates to the use of polymers containing carboxyl groups and polyalkylene ether side chains as additives in mineral building materials.
For the purposes of the present invention, mineral building materials are preparations comprising as essential constituents mineral binders such as lime and/or, in particular, cement and also, as aggregates, sands, gravels, crushed rock or other fillers, e.g. natural or synthetic fibers. The mineral building materials are generally produced by mixing the mineral binders and the aggregates together with water to convert them into a ready-to-use preparation which when left to itself hardens with time both in air and under water to give a stone-like material.
To obtain the desired processing property profile of the ready-to-use preparation it is generally necessary to use a larger amount of water than that required for the subsequent hydration or curing process. This is the case particularly when a high flowability of the ready-to-use preparation is desired, for example when it is to be pumped. The excess water which evaporates later forms voids in the building component and these lead to a significant worsening of the mechanical properties and resistances of the building component.
To reduce the amount of excess water while maintaining a prescribed property profile, additives which are generally referred to as water reducing agents, flow improvers and fluidizers are generally added to the ready-to-use preparation. According to the prior art, for example, the following compounds are recommended as fluidizers for ready-to-use preparations of mineral building materials:
Naphthalenesulfonic acid-formaldehyde condensates (EP-A 402 319), melamine-formaldehyde polycondensates (EP-A 402 319), ligninesulfonates (EP-A 402 319) and also homopolymers and copolymers of carboxylic acids and dicarboxylic acids with styrene (EP-A 306 449 and U.S. Pat. No. 3,952,805) or isobutene or diisobutene (DE-A 37 16 974, EP-A 338 293, DE-A 39 25 306, U.S. Pat. No. 4,586,960, U.S. Pat. No. 4,042,407 and U.S. Pat. No. 4,906,298). EP 97 513 describes the use of copolymers of unsaturated carboxylic acids and hydroxyalkyl esters of unsaturated carboxylic acids as plasticizer additives in cement-containing compositions.
The use of copolymers comprising carboxylic acid monomers and polyalkylene oxide esters of acrylic acid and methacrylic acid in copolymerized form as fluidizers for cement-containing compositions is known from DE-A 44 20 444. However, the fluidizers have to be used together with antifoams based on alkylene polyethers in order to achieve the desired use properties.
The use of crosslinked polymers of ethylenically unsaturated polyoxialkylene ethers, multiply unsaturated alkenylethers and maleic anhydride as fluidizers for cement-containing compositions is described in EP 619 277. However, the polyfunctional compounds which are absolutely necessary for the desired properties are complicated to prepare and make the product more expensive.
DE-A 195 13 126 describes copolymers based on oxialkylene glycol-alkenyl ethers and unsaturated dicarboxylic acid derivatives which comprise at least one further monomer selected from among multiply unsaturated monomers or diesters of ethylenically unsaturated carboxylic acids in copolymerized form. Such terpolymers are likewise suitable for fluidizing cement-containing compositions.
DE-A 4304 109 and EP-A 610 699 describe copolymers based on maleic acid derivatives and vinyl monomers with the maleic acid derivatives including maleimides and monoamides of maleic acid and also, as an essential component, a monoester of maleic acid and a polyalkylene alcohol. Such polymers are likewise suitable as fluidizers for cement-containing mineral building materials. However, it appears to be desirable to further reduce the water/cement ratio of 0.5 given in the examples for flowable preparations in order to achieve a higher strength of the set concrete.
EP-A 537 870 describes copolymers of ethylenically unsaturated carboxylic acids and/or sulfonic acids with monomers containing polyether functions. Monomers described are, for example, allyl ethers of polyethylene glycol having up to 11 ethylene oxide units. The polymers are preferably prepared in the presence of sodium hypophosphite.
In summary, it can be said that the additives known from the prior art for mineral building materials are still in need of improvement. In particular, their fluidizing action at low water/binder ratios is generally still not sufficient or is retained for only a short time. Although a larger amount of the fluidizer can partially compensate for this deficiency, it not only makes such a procedure uneconomical but also results in considerable deterioration of the achievable mechanical strength or at least unacceptable slowing of the setting rate.
It is an object of the present invention to provide additives for mineral building materials which, particularly in respect of their fluidizing action, have advantages over the known additives for mineral building materials. In particular, it is desirable that in the case of low water/binder ratios there is no need to accept disadvantages in the setting behavior or in respect of the strength of the set building materials.
We have found that this object is achieved by a series of water-soluble or water-dispersible polymers which have carboxyl groups and side chains having a polyether structure and have advantageous properties as additives for mineral building materials if they are obtained by polymerization of ethylenically unsaturated monomers containing carboxyl groups and/or side chains having a polyether structure in the presence of phosphorus-containing compounds. Alternatively, such polymers can be obtained by polymer-analogous reaction of polymers which have been prepared in the presence of phosphorus-containing compounds and contain reactive groups.
The present invention accordingly provides for the use of water-soluble or water-dispersible polymers containing carboxyl groups, if desired in latent form, and side chains of the formula I,
—X—Y&Brketopenst;O&Parenopenst;Alk-O)
n
—R]
k
  (I),
where
k is 1, 2, 3 or 4,
Y is a single bond or a C
1
-C
4
-alkylene unit or, when k≠1, can also be
X is a single bond or a carbonyl group or, when Y is not a single bond, can also be O, NR′,
 where R′ is hydrogen, C
1
-C
20
-alkyl, C
5
-C
10
-cycloalkyl, C
6
-C
20
-aryl, C
1
-C
20
-alkanoyl, C
7
-C
21
-aroyl, (Alk-O)
n
—R or -Alk′-O(Alk-O)
n
—R,
Alk is C
2
-C
4
-alkylene,
Alk′ is C
1
-C
4
-alkylene which may also bear an OH group,
n is a number in the range from 1 to 300, where n≧12 when X is a single bond and n ≧2 when X is a carbonyl group and Y is a single bond,
R is hydrogen, C
1
-C
20
-alkyl, C
5
-C
8
-cycloalkyl, C
6
-C
20
-aryl, C
1
-C
20
-alkanoyl or C
7
-C
21
-aroyl,
where the polymers are obtainable by free-radical copolymerization of ethylenically unsaturated monomers A containing carboxyl groups and ethylenically unsaturated monomers B having side chains of the formula I and also, if desired, further monomers C in the presence of from 0.1 to 50 % by weight, based on the monomers to be polymerized, of phosphorus-containing compounds,
or by free-radical copolymerization of ethylenically unsaturated monomers containing reactive functional groups, if desired together with monomers A and/or B and, if desired, further monomers C, in the presence of from 0.1 to 50 % by weight, based on the monomers to be polymerized, of phosphorus-containing compounds and subsequent conversion of at least part of the reactive functional groups into side chains of the formula I and/or carboxyl groups,
as additives in mineral building materials.
The present invention further provides the polymers used if n≧5 when X is a carbonyl group and n>12 when X is a single bond. The present invention also provides a process for preparing these polymers.
In the following, C
1
-C
20
-alkyl is a linear or branched, saturated hydrocarbon chain having up to 20, preferably from 1

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