Aqueous foam

Abstract

Aqueous Foam. The present invention relates to an aqueous foam comprising air, water, a hydrophobic polymer powder, and optionally acid. It further relates to a kit for manufacturing the foam, a method for manufacturing the kit, a method for manufacturing the foam, the use of the acid-free foam for protecting buildings and / or trees against fire and / or for extinguishing hydrocarbon fires, and the use of the foam containing acid for cleaning and / or stripping concrete and / or mortar on all handling or manufacturing equipment for mortar or concrete. It also relates to a method for cleaning formwork using the acid foam according to the invention and finally, the use of an aqueous solution of acid and a hydrophobic polymer powder for manufacturing an acidic aqueous foam.

Description

Title of the invention: Aqueous foam Technical field

[0001] The present invention relates to the field of cleaning formwork, in particular hips, more particularly coated with a non-stick coating for concrete, and acidic aqueous foams intended in particular for vertical surfaces. Prior art

[0002] Stripping formwork surfaces such as hips soiled by a film of concrete or laitance remaining adhering to the support can be done mechanically (by scraping, etc.) or chemically by acid attack (diluted acid) of the concrete film.

[0003] The chemical technique is the simplest to use and works well on horizontal surfaces - In vertical applications, the acidic water runs down the wall and its effectiveness is reduced because it does not remain in sufficient contact with the surface. In addition, the acid chemically attacks the metal of the hips - When the hips are coated with a non-stick coating for concrete (such as KEB ANCHE, for example, as described in patent application FR21 02907), the metal support is protected from chemical attack by the acid solution by the non-stick coating.

[0004] The inventors surprisingly discovered that it was possible to make an acid foam from the diluted acid and that this foam did not flow on vertical surfaces, which made it very effective in stripping formwork surfaces such as hips, particularly vertical ones. This compact and adherent foam thus allows a longer and more penetrating action and can accelerate the cleaning / stripping of formwork surfaces such as hips or other supports. Furthermore, this foam is free of surfactants.

[0005] The inventors also surprisingly discovered that this acid-free foam could be used to protect homes and / or trees against fire and / or to extinguish hydrocarbon fires. Statement of the invention

[0006] The present invention therefore relates to an aqueous foam comprising, advantageously consisting essentially of, in particular consisting of, air, water, a hydrophobic polymer powder and optionally acid.

[0007] Advantageously, the hydrophobic polymer powder according to the invention is chosen from a polyamide or copolyamide powder, a lignin powder and their mixtures. In particular, it is a polyamide or copolyamide powder, more particularly a copolyamide powder. Advantageously, the powder of polyamide or copolyamide is chosen from polyamide 12, polyamide 6, copolyamide 6 / 12 and their mixtures. In particular, it is copolyamide 6 / 12, more particularly comprising a molar proportion of 50% of polyamide 12. The polyamide or copolyamide powder according to the invention may have a volume average diameter D50 measured by a Coulter counter, in particular according to standard ISO 13319, of between 5 and 60 micrometers, advantageously between 5 and 40 micrometers, more advantageously between 5 and 20 micrometers, in particular between 8 and 15 micrometers, more particularly 10 micrometers. Particularly advantageously, the polyamide or copolyamide powder has a very narrow particle size distribution, in particular a maximum of 10% of the particles have a diameter of less than 5 micrometers and / or a maximum of 5% of the particles have a diameter of more than 20 micrometers, measured by a Coulter counter, in particular according to ISO 13319.In an advantageous embodiment, the polyamide or copolyamide powder according to the invention has a spheroidal shape. It may advantageously be porous and advantageously has an average specific surface area measured according to the BET method, in particular according to the ISO 9277 standard, of between 1 m2 / g and 30 m2 / g, more advantageously between 10 m2 / g and 25 m2 / g, more particularly it is 20 m2 / g. The polyamide or copolyamide powder according to the invention may have a melting point of between 130°C and 180°C, advantageously between 135°C and 150°C, in particular 142°C, measured according to the ISO 11357-3 standard. The polyamide or copolyamide powder according to the invention may have an unpacked apparent density of between 0.2 g / cm3 and 0.3 g / cm3, in particular 0.265 g / cm3, measured according to standard ISO 1068. It may be commercially available from the company Arkema under the name ORGASOL®.

[0008] In an advantageous embodiment, the content of hydrophobic polymer powder in the foam according to the invention is between 5 and 15% by weight, advantageously between 7 and 13% by weight, more advantageously it is 10% by weight, relative to the total weight of the foam.

[0009] Advantageously, the foam according to the present invention comprises acid. It is therefore an acid foam. Advantageously, the acid is chosen from hydrochloric acid and acetic acid, more advantageously it is hydrochloric acid. In an advantageous embodiment, the acid content of the foam according to the invention is between 1 and 11% by weight, advantageously between 4 and 11% by weight, more advantageously it is 10% by weight, relative to the total weight of the foam.

[0010] The foam according to the present invention is advantageously free of surfactants.

[0011] The thickness of the foam according to the present invention is advantageously between 0.4 mm and 20 cm. Its density is advantageously 0.5.

[0012] The present invention further relates to a kit for manufacturing the foam according to the invention comprising water, optionally acid, in particular in the form of an acidic aqueous solution, and the hydrophobic polymer powder, in particular as described above, advantageously in the form of a premix. The present invention therefore advantageously relates to this premix. In an advantageous embodiment, the kit or premix according to the invention is free of surfactants.

[0013] The present invention further relates to a method for manufacturing the kit according to the present invention or the premix according to the invention, said method comprising the following successive steps: - a) the possible creation of an acidic aqueous solution; - b) adding the hydrophobic polymer powder to the water or the possible aqueous solution obtained in step a).

[0014] Step a) is therefore optional for the foams according to the invention not containing acid.

[0015] Step a) is in particular carried out by diluting a commercial acid in water.

[0016] The present invention further relates to a method of manufacturing the foam according to the present invention comprising the following successive steps: - c) mixing with an agitator, advantageously having a rotation speed of 1900 rpm, in particular electric, water or the optional aqueous acid solution and hydrophobic polymer powder, in particular as described above, more particularly in the form of the kit and / or the premix, so as to incorporate air and form a foam; - d) recovery of the foam thus obtained.

[0017] Advantageously, the foam is produced in situ, just before its use, more advantageously using the kit according to the invention.

[0018] The present invention further relates to the use of the acid-free foam (also referred to as acid-free foam) according to the invention for protecting homes and / or trees against fire and / or for extinguishing hydrocarbon fires.

[0019] The present invention further relates to the use of the acid foam (also called foam comprising acid) according to the invention for cleaning and / or stripping concrete and / or mortar on all equipment for handling or manufacturing mortars or concretes, advantageously hips, in particular coated with a non-stick coating for the concrete.

[0020] Indeed, advantageously, the acid-free foam according to the invention can be sprayed onto homes (for example 10 to 20 cm if necessary) and / or trees to be protected. which will prevent them from being affected by the fire and therefore not only protect them but also limit the spread of the fire.

[0021] Furthermore, the acid-free foam according to the invention can be sprayed onto hydrocarbon fires, which will enable them to be extinguished. In fact, the foam according to the invention is insulating and will therefore protect these fires against the action of air, which therefore prevents the spread of fires and will even allow these fires to be extinguished by smothering them.

[0022] In a particularly advantageous manner, the acid foam according to the invention will be used to clean and / or strip concrete and / or mortar, in particular laitance, on all equipment for handling or manufacturing mortars or concrete, in particular by removing all traces thereof. In a particularly advantageous manner, the acid foam according to the invention is used to clean and / or strip formwork surfaces such as hips, more particularly vertical surfaces, even more particularly metallic surfaces. In a particularly advantageous manner, the acid foam according to the invention is used to clean and / or strip formwork surfaces such as hips coated with a non-stick coating, in particular concrete, more particularly as described in patent application FR21 02907.

[0023] The present invention further relates to a method for cleaning hips, in particular coated with a non-stick concrete coating comprising: - A) the application to the formwork, in particular the surface of the formwork, more particularly vertical, advantageously with a spatula or by spraying with a low pressure pump, of the foam comprising acid according to the invention; - B) after a contact time of between 20 minutes and 1 hour, cleaning the foam, advantageously with clean water (for example with a jet of clean water, without pressure necessary) or by scraping, in particular with a wide rubber scraper which will carry away the foam and dissolved cement.

[0024] The present invention finally relates to the use of an aqueous acid solution and a hydrophobic polymer powder for the manufacture of an acidic aqueous foam, in particular according to the invention, the hydrophobic polymer powder being advantageously chosen from a polyamide or copolyamide powder, a lignin powder and their mixtures, said foam being advantageously free of surfactants. Advantageously, the aqueous acid solution and the hydrophobic polymer powder are as described above.

[0025] The present invention will be better understood on reading the description of the examples which follow, which are given for non-limiting information purposes. Example 1: Making an acid foam and using it for cleaning hips

[0026] A solution of 20% commercial hydrochloric acid (diluted to 23%) in water is made.

[0027] A 6 / 12 copolyamide powder comprising a molar proportion of 50% of polyamide 12 having a volume average diameter D50 measured by a 10 micrometer Coulter counter, marketed by the company Arkema under the name ORGASOL®, is added to the solution at a rate of 10% by weight.

[0028] A bucket with a capacity of 10L, containing 5L of the acid solution + copolyamide 6 / 12 powder is thus manufactured.

[0029] Before use, for example on a construction site, mix with an electric stirrer having a rotation speed of 1900 rpm.

[0030] The foam is created and applied to the formwork coated with a non-stick concrete coating (KEBANCHE as described in patent application FR21 02907) using the following techniques: - spreading with a spatula or; - spraying with a low pressure pump.

[0031] After a contact time of 20 minutes to 1 hour maximum, the foam is cleaned with a jet of clear water (no pressure necessary) or scraped with a large rubber scraper which carries away the foam and dissolved cement.

Claims

Claims

1. Aqueous foam comprising, advantageously consisting of, air, water, a hydrophobic polymer powder and optionally acid, the hydrophobic polymer powder being chosen from a polyamide or copolyamide powder, a lignin powder and their mixtures, and said foam being free of surfactants.

2. Foam according to claim 1, characterized in that the hydrophobic polymer powder is a polyamide or copolyamide powder, advantageously chosen from polyamide 12, polyamide 6, copolyamide 6 / 12 and their mixtures, in particular it is copolyamide 6 / 12.

3. Foam according to claim 2, characterized in that the polyamide or copolyamide powder has a volume average diameter D50 measured by a Coulter counter of between 5 and 60 micrometers, advantageously between 5 and 20 micrometers, in particular 10 micrometers.

4. Foam according to any one of claims 1 to 3, characterized in that its content of hydrophobic polymer powder is between 5 and 15% by weight, advantageously it is 10% by weight, relative to the total weight of the foam.

5. Foam according to any one of claims 1 to 4, characterized in that it comprises acid, advantageously chosen from hydrochloric acid and acetic acid, more advantageously it is hydrochloric acid.

6. Foam according to claim 5, characterized in that its acid content is between 1 and 11% by weight, advantageously between 4 and 11% by weight, relative to the total weight of the foam.

7. Foam according to any one of claims 1 to 6, characterized in that its thickness is between 0.4 mm and 20 cm.

8. Foam according to any one of claims 1 to 7, characterized in that its density is 0.

5.

9. Kit for manufacturing the foam according to any one of claims 1 to 8, said kit comprising water, optionally acid, in particular in the form of an acidic aqueous solution, and the hydrophobic polymer powder, advantageously in the form of a premix.

10. A method of manufacturing the kit according to claim 9 comprising the following successive steps - a) the possible production of an acidic aqueous solution; - b) the addition of the hydrophobic polymer powder into the water or into the possible acidic aqueous solution obtained in step a).

11. Process for manufacturing the foam according to any one of claims 1 to 8 comprising the following successive steps: - c) mixing with a stirrer, in particular an electric stirrer, water or the optional aqueous acid solution and the hydrophobic polymer powder so as to incorporate air and form a foam - d) recovering the foam thus obtained.

12. Use of the acid-free foam according to any one of claims 1 to 4 and 7 to 8 for protecting homes and / or trees against fire and / or for extinguishing hydrocarbon fires.

13. Use of the foam comprising acid according to any one of claims 1 to 8 for cleaning and / or stripping concrete and / or mortar on all equipment for handling or manufacturing mortars or concretes, advantageously the hips, in particular coated with a non-stick coating of the concrete.

14. Method for cleaning hips, in particular coated with a non-stick concrete coating, comprising: - A) applying to the formwork, advantageously with a spatula or by spraying with a low-pressure pump, the foam comprising acid according to any one of claims 1 to 8; - B) after a contact time of between 20 minutes and 1 hour, cleaning the foam, advantageously with clear water or by scraping.

15. Use of an aqueous acid solution and a hydrophobic polymer powder for the manufacture of an acidic aqueous foam according to any one of claims 1 to 8, the hydrophobic polymer powder being chosen from a polyamide or copolyamide powder, a lignin powder and their mixtures, said foam being free of surfactants.