Patent Application
20080085952
In the examples below, the preparation of different polymers as defined above is described.
There is introduced into a 1 l reactor which is provided with mechanical agitation means, a heating system and nitrogen inerting:
A solution of an initialising agent is prepared by weighing 0.49 g of 2,2′-azobis-(2,4-dimethylvaleronitrile) (Vazo 52 from Dupont) in 10.0 g of tetrahydrofuran (THF).
The reaction medium is heated to 60° C. with agitation and with degassing being carried out under N2. The initialising solution is added to the reaction medium and it is reacted for 5 hours 30 mins. at a temperature of 60° C. In order to stabilise the THF, a small quantity of water is added. Distillation is subsequently carried out under a vacuum in order to eliminate the solvent.
The product obtained is a viscous liquid which is diluted with water in order to obtain a solution having a concentration of approximately 30% by weight.
The molar mass of the co-polymer obtained is Mw=45240.
There is introduced into a 1 l reactor which is provided with mechanical agitation means, a heating system and nitrogen inerting:
A solution of an initialising agent is prepared by weighing 0.68 g of 2,2′-azobis-(2,4-dimethylvaleronitrile) (Vazo 52 from Dupont) in 10.0 g of tetrahydrofuran (THF).
The reaction medium is heated to 60° C. with agitation and with degassing being carried out under N2. The initialising solution is added to the reaction medium and the solution is reacted for 5 hours 30 mins. at a temperature of 60° C. In order to stabilise the THF, a small quantity of water is added. Distillation is subsequently carried out under a vacuum in order to eliminate the solvent.
The product obtained is a viscous liquid which is diluted with water in order to obtain a solution having a concentration of approximately 30% by weight.
There is introduced into a 1 l reactor which is provided with mechanical agitation means, a heating system and nitrogen inerting:
A solution of an initialising agent is prepared by weighing 0.61 g of 2,2′-azobis-(2,4-dimethylvaleronitrile) (Vazo 52 from Dupont) in 10.0 g of tetrahydrofuran (THF).
The reaction medium is heated to 60° C. with agitation and with degassing being carried out under N2. The initialising solution is added to the reaction medium and the solution is reacted for 5 hours 30 mins. at a temperature of 60° C. In order to stabilise the THF, a small quantity of water is added. Distillation is subsequently carried out under a vacuum in order to eliminate the solvent.
The product obtained is a viscous liquid which is diluted with water in order to obtain a solution having a concentration of approximately 30% by weight.
There is introduced into a 1 l reactor which is provided with mechanical agitation means, a heating system and nitrogen inerting:
A solution of an initialising agent is prepared by weighing 0.59 g of 2,2′-azobis-(2,4-dimethylvaleronitrile) (Vazo 52 from Dupont) in 10.0 g of tetrahydrofuran (THF).
The reaction medium is heated to 60° C. with agitation and with degassing being carried out under N2. The initialising solution is added to the reaction medium and the solution is reacted for 5 hours 30 mins. at a temperature of 60° C. In order to stabilise the THF, a small quantity of water is added. Distillation is subsequently carried out under a vacuum in order to eliminate the solvent.
The product obtained is a viscous liquid which is diluted with water in order to obtain a solution having a concentration of approximately 30% by weight.
There is introduced into a 1 l reactor which is provided with mechanical agitation means, a heating system and nitrogen inerting:
A solution of an initialising agent is prepared by weighing 0.59 g of 2,2′-azobis-(2,4-dimethylvaleronitrile) (Vazo 52 from Dupont) in 10.0 g of tetrahydrofuran (THF).
The reaction medium is heated to 60° C. with agitation and with degassing being carried out under N2. The initialising solution is added to the reaction medium and the solution is reacted for 5 hours 30 mins. at a temperature of 60° C. In order to stabilise the THF, a small quantity of water is added. Distillation is subsequently carried out under a vacuum in order to eliminate the solvent.
The product obtained is a viscous liquid which is diluted with water in order to obtain a solution having a concentration of approximately 30% by weight.
There is introduced into a 1 l reactor which is provided with mechanical agitation means, a heating system and nitrogen inerting:
The reaction medium is heated to 60° C. with agitation and with degassing being carried out under N2. 0.59 g of 2,2′-azobis-(2,4-dimethylvaleronitrile) (Vazo 52 from Dupont) are added to the reaction medium as an initialising agent and the solution is reacted for 5 hours 30 mins. at a temperature of 60° C.
The product obtained is a viscous liquid which is diluted with water in order to obtain a solution having a concentration of approximately 30% by weight.
There is introduced into a 1 l reactor which is provided with mechanical agitation means, a heating system and nitrogen inerting:
A solution of an initialising agent is prepared by weighing 0.61 g of 2,2′-azobis-(2,4-dimethylvaleronitrile) (Vazo 52 from Dupont) in 10.0 g of tetrahydrofuran (THF).
The reaction medium is heated to 60° C. with agitation and with degassing being carried out under N2. The initialising solution is added to the reaction medium and the solution is reacted for 5 hours 30 mins. at a temperature of 60° C. In order to stabilise the THF, a small quantity of water is added. Distillation is subsequently carried out under a vacuum in order to eliminate the solvent.
The product obtained is a viscous liquid which is diluted with water in order to obtain a solution having a concentration of approximately 30% by weight.
There is introduced into a 1 l reactor which is provided with mechanical agitation means, a heating system and nitrogen inerting:
A solution of an initialising agent is prepared by weighing 0.62 g of 2,2′-azobis-(2,4-dimethylvaleronitrile) (Vazo 52 from Dupont) in 10.0 g of tetrahydrofuran (THF).
The reaction medium is heated to 60° C. with agitation and with degassing being carried out under N2. The initialising solution is added to the reaction medium and the solution is reacted for 5 hours 30 mins. at a temperature of 60° C. In order to stabilise the THF, a small quantity of water is added. Distillation is subsequently carried out under a vacuum in order to eliminate the solvent.
The product obtained is a viscous liquid which is diluted with water in order to obtain a solution having a concentration of approximately 30% by weight.
There is introduced into a 1 l reactor which is provided with mechanical agitation means, a heating system and nitrogen inerting:
A solution of an initialising agent is prepared by weighing 0.63 g of 2,2′-azobis-(2,4-dimethylvaleronitrile) (Vazo 52 from Dupont) in 10.0 g of tetrahydrofuran (THF).
The reaction medium is heated to 60° C. with agitation and with degassing being carried out under N2. The catalyst solution is added to the reaction medium and the solution is reacted for 5 hours 30 mins. at a temperature of 60° C. In order to stabilise the THF, a small quantity of water is added. Distillation is subsequently carried out under a vacuum in order to eliminate the solvent.
The product obtained is a viscous liquid which is diluted with water in order to obtain a solution having a concentration of approximately 30% by weight.
There is introduced into a 1 l reactor which is provided with mechanical agitation means, a heating system and a distillation column:
Heating is carried out to 170° C. after distillation of the water contained in the raw materials under high vacuum of 10 mmHg until all the ethylene polyoxide has reacted (that is, 7 hours) . Cooling is then carried out to 80° C. and there is added:
Addition is carried out slowly for 3 minutes and it is allowed to react for 30 minutes at 80° C. The product becomes quite viscous but remains soluble. Dilution with water is then carried out in order to have a product of 20% of dry extract.
a. Characterising the Co-Polymers Prepared
The molar mass of the co-polymers prepared is established by gel permeation chromatography (GPC) using the aqueous method under the following conditions:
Internal standard calibration PEG Mp 260 at 300,000.
The molar masses of the co-polymers prepared in accordance with Examples 1 to 9 were established by GPC as indicated above and are set out in Table 1 below.
b. Measuring the Spread
The spread of the cement compositions is established in accordance with the following protocol at constant temperature.
A frustoconical mould which has no base and which is a reproduction on a scale of 0.5 of the Abrams cone is used and is characterised by the following dimensions:
This cone is filled with the sample in the fresh state in three layers of identical volume, then the sample is pierced between each layer using a steel rod having a diameter of 6 mm, a length of 300 mm and a spherical end. Subsequently, the upper surface of the cone is shaved, then it is removed from the mould onto a clean surface and the cone is raised vertically. The settlement is measured at the highest point and the spread is measured according to four diameters at 45° C. with a sliding calliper. The spread is given by the mean of the four measurements.
c. Metering Tests
The additives obtained, in the form of co-polymers prepared in an aqueous solution at approx. 30% by weight, were tested in terms of the useful measure. To that end, the quantity of additive necessary to obtain a spread of approximately 320±10 mm for a mortar prepared in the following manner was established:
1350.4 g of standardised ISO sand is introduced in the bowl of a mixer (Perrier BA 008). Then 6% by mass, in terms of the sand, of wetting water was added with mixing at a rate of approximately 140 rpm within 30 seconds. Mixing was continued for 30 seconds before the admixture was allowed to rest for 4 minutes. Subsequently, 624.9 g of the specified cement and 412.1 g of calciferous filler were added (BL 200, OMYA), then mixed for 1 minute before adding the mixing water and the specified measure of additive, whilst still mixing. After those steps, mixing was continued for a further 2 minutes at 280 rpm.
The tests were carried out for the additives prepared in examples 1 to 9 and a reference product of the polycarboxylate type (Glenium 27 from Master Builder Technologies), which, similarly to the additive according to example 9, does not comprise any silanol group.
It is evident that the metering deviation between the cements is distinctly higher for the reference product than for the additives based on a polymer carrying a silyl group in the Examples 1 to 8.
It will further be appreciated that the additive according to Example 9, which is prepared similarly to the other polymers but without any silylated compound, has a deviation comparable to the commercially available product and, in any case, far greater than that of the co-polymers having a silanol group.
Thus, it appears from these results that the presence in the polymer of a group capable of hydrolysing to form a silanol group reduces the variation in metering between different cements and thereby allows an improvement in the robustness of the additive.
Another series of tests was carried out on mortars comprising, as a granulate, standardised sand and four cements A, B, C and D having a different content in terms of soluble alkalines.
The mortars were prepared in accordance with the protocol described above.
The measure of additive for each of the four cements, established in accordance with Standard N196 and expressed as a percentage relative to the weight of cement of the mortar, is indicated in Table 3 below:
The measure for cement A having a very low content of soluble alkalines is, in all the cases studied, lower than for cement B having a very high content of soluble alkalines; however, it will readily be observed that this difference becomes less clear for the additives of examples 7, 8 and 10 based on a polymer carrying a silyl group compared with the reference additives or additives of example 9 which do not comprise this type of group.
c. Workability Retention Tests
The additives prepared were characterised in terms of retaining workability by means of the following tests.
The evolution of the spread of the mortars prepared in accordance with the procedure above was evaluated as indicated above at 5, 15, 30, 60 and 90 minutes of preparation. The results are set out in Tables 4a to 4e below.
The workability retention is substantially equal to Glenium 27 but with a lower measure which is 0.11-0.50-0.33-0.25 for Glenium 27, respectively.
Therefore, there is observed for all the cements tested a fluidity retention over time that is comparable to the reference product, in spite of the strong reduction in the measure of additive.
| Number | Date | Country | Kind |
|---|---|---|---|
| 0410499 | Oct 2004 | FR | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/FR05/02438 | 10/4/2005 | WO | 00 | 4/5/2007 |
