Patent Application
20080028977
A composition according to the present invention is made as follows.
The composition comprises (N.B. all components amounts are given by weight, i.e. w/w):
The tap water is heated to a temperature of 53° C.—i.e. just above the melting point of Span™ 60.
Moderate agitation is applied to the water using baffles to avoid aeration.
The Span™ 60 and Brij™ 72 are added to the water. Once the surfactants are completely melted the rate of agitation is increased for 5 to 10 minutes.
The batch is then allowed to cool. Agitation is reduced to the moderate rate and continued during the cooling phase.
Drumming of the composition may be conducted while the composition is around 40° C. to 50° C., while the viscosity is still moderately low.
Another composition according to the present invention is made as follows.
The composition comprises:
The water is heated to 80° C. Moderate agitation is applied to the water using baffles to avoid aeration.
The remaining procedure is essentially identical to Example 1.
The methods of manufacture of compositions described in examples 1 and 2 are suitable for small scale production, e.g. in a laboratory. It would, however, be routine to the person skilled in the art to scale the procedure up for large scale production.
A sample of the composition was tested for its rheological properties. The sample contained the following components:
From shear rates of 1 to 1000s−1 the sample shows power law shear thinning behaviour at 25° C. (see
Laboratory evaluations were performed to demonstrate the efficacy of a composition according to the present invention as a concrete release agent.
The composition used was as in Example 2.
This work evaluated release of concrete from both steel and wood substrates. In each case an effective release was realized using the following conditions as compared to the use of diesel fuel as a release agent/lubricant.
The test process was as follows:
The results were as follows:
A “shift” of the concrete from the treated substrate (steel and wood) was observed in each of the listed conditions:
Wet concrete applied to untreated wood and steel adhered noticeably, though with time and mild agitation it was found to release.
The conditions in this laboratory setting were useful and revealing, but not fully representative of real world situations. It is to be expected that in the real world the use of vibration and additional pressure, due to the weight of concrete or the moulding process, would cause far greater bonding of the concrete to the surfaces it contacts. In such conditions the efficacy of the composition of the present invention would be expected to be accentuated and the results be more emphatic.
A major difference observed in these investigations was the amount of residue remaining on the substrate—this is an important consideration, particularly in the moulding applications. The lowest amount of residue that was qualitatively observed to remain on the substrate was effected by the 2:1 dilution of the test composition, followed by the neat test composition (dry or wet), followed by diesel fuel, then the untreated surfaces.
The 2:1 water dilution of the test composition as mentioned above was hand-sprayed onto a clean, vertical glass surface. No runoff or movement of the residue was observed.
This clearly illustrates the rapid reforming property observed in the abovementioned studies into the composition's rheological properties. Additionally, the residue/film that formed was not smooth but assumed the coarse spray pattern, further demonstrating the rapid setting properties. Of course a finer, more even coating could be achieved using finer spray technology which is known in the art.
In further trials, compositions according to the present invention were found to perform extremely well in the release of asphalt from truck beds and moulded concrete structures from their moulds. A further aspect of note was the lack of a build up of residue on the treated substrates, which is particularly significant in mould release applications. This further demonstrates the efficacy of the compositions of the present invention in as release agents.
