EP0917601A1

EP0917601A1 - Adherence primer for bituminous apron and/or surfacing for circulation in structural works or buildings

Info

Publication number: EP0917601A1
Application number: EP97935658A
Authority: EP
Inventors: Jeannot Beritzki; Michel Netter; Francis Ovaert
Original assignee: SMAC SAS
Current assignee: SMAC SAS
Priority date: 1996-08-07
Filing date: 1997-07-30
Publication date: 1999-05-26
Anticipated expiration: 2017-07-30
Also published as: EP0917601B1; FR2752250A1; AU3856097A; DE69704562D1; WO1998005823A1; FR2752250B1

Abstract

The invention concerns an adherence primer for bituminous apron and/or surfacing for circulation, to be applied on a surface of a structure or building previous to the said bituminous surfacing, the said surface constituting a polar support. The primer contains at least one polymer or copolymer in solution or dispersion, with a base structure of relatively low polarity, the said polymer or copolymer being capable of forming a layer substantially impermeable to water vapour, enabling both the adherence of the primer to the bituminous surfacing, and to the said surface of the structure or building while substantially eliminating risks of blistering. The invention also concerns a bituminous apron and/or coating for circulation carried out by means of this primer and the method for producing it.

Description

Adhesion primer for bituminous waterproofing and / or circulation coating of construction works or buildings

The present invention relates to a primer for waterproofing and / or circulation coating based on bitumen and / or asphalt, which can be used on construction works or buildings. It also relates to the waterproofing and / or circulation coatings formed using such a primer, as well as to a process for producing such coatings on surfaces of construction works or buildings. A waterproofing coating constitutes a continuous element which can be obtained in particular by hot application of bitumen-based sheets, optionally comprising one or more reinforcements, assembled together by covers welded by flame or bonded by bitumen melted with heat, forming a bituminous membrane; by pouring asphalt continuously by forming one or more superimposed layers; or. again by combining the two previous techniques.

A traffic surface also constitutes a continuous element formed, on a roadway or a construction work such as a bridge deck, by deposit of a bituminous mix or concrete (mixture based on sand or pebbles bonded with bitumen) spread in a uniform layer (s) or by pouring asphalt, possibly over a waterproofing coating. A road surface must in particular have good resistance to deformation under the effect of repeated passage of vehicles, their acceleration or braking, good impact resistance, etc.

It is often necessary or recommended that the waterproofing and / or circulation coatings adhere to their support.

For this purpose, when the support is metallic, for example galvanized sheet steel, lead, aluminum or zinc, or based on hydraulic binder, for example concrete or mortar, a primer is spread in a thin layer on the surface of the support before the coating is produced. The functions of this primer can be multiple, it being used in particular for hanging the coating on the support, for temporary protection of the support against bad weather (rain, dew, etc.) pending the completion of the coating (s) ( s) final (s), impregnating to a certain depth from the surface when the support is porous, and as a means of preventing blistering of the sealing and / or circulation coating, in particular when the support is permeable to gas, especially steam. The blistering phenomenon is generally caused by the vaporization of moisture still present in permeable substrates such as concrete or cement mortar, under the effect of heating. The latter may be due to the sun, the waterproofing coating often remaining exposed to it before the wearing course is deposited. The heating may also be due to the subsequent application of the bituminous coating (s), which is carried out hot. This vaporization is in fact accompanied by an increase in the pressures of the gases inside the protected structure, the pressure being applied in particular to the lower surface of the sealing coating. Due in particular to their very low permeability to gases and to their thermoplasticity, the bituminous coatings can peel off locally if the primer is not sufficiently efficient, thus forming blisters of various dimensions according to their rigidity and the pressure.

The origin of one overheating which can cause the blistering phenomenon is therefore multiple, and this risk can manifest itself at different times during the sealing of a structure. The primers most commonly used under bituminous coatings, whether they are coatings based on bituminous sheets, based on poured asphalt or mixed systems, are based on bitumen solubilized in solvents. Bitumen emulsions and more rarely epoxy resins are also used.

Bituminous primers, which are single-component, wet the supports to which they are applied because of their surface tension, but have a low affinity for polar supports such as concrete or metal due to their low polarity.

In addition, after drying, these primers have low internal cohesion and are highly thermoplastic. Consequently, they do not make it possible to effectively avoid blistering phenomena.

Conversely, primers based on epoxy resins adhere well to polar supports such as concrete or metal, being themselves polar, and can therefore resist blistering. These primaries are also used more particularly for bridge decks intended for traffic.

On the other hand, these primers are generally two-layered and have little affinity for bituminous coatings which are, for their part, not very polar. Therefore, it is often necessary to incorporate on the surface of these resins, grains such as for example grains of sand, so that the bituminous coatings can be attached "mechanically". This technique, in addition to its complexity, becomes problematic on sloping or vertical supports.

Also, given the drawbacks and problems encountered with the primers currently available, there remains a demand for primers for bituminous coatings making it possible to avoid the blistering phenomenon while ensuring satisfactory adhesion qualities of these bituminous coatings, in particular on polar supports like concrete.

Consequently, the objective of the present invention is to provide a one-component adhesion primer, making it possible to avoid the blistering phenomenon mentioned above, whatever the origin and the moment of heating.

Another objective of the invention is to provide such a primer which at the same time has a good affinity both with respect to polar supports such as concrete and bituminous coatings, which are not very polar, and making it possible to obtain satisfactory adhesion of the bituminous coating on such supports. Another objective is also to provide a primer which can be used in particular for construction and traffic works such as bridge decks and which makes it possible to meet the requirements of road surfaces. To this end, the subject of the present invention is an adhesion primer for bituminous waterproofing and / or circulation coating, intended to be applied to a surface of a construction work or building prior to said bituminous coating, said surface constituting a polar support, characterized in that it comprises at least one polymer or copolymer in solution or in dispersion, of relatively weakly polar basic structure and whose chain has at least one group during polar, said polymer or copolymer being capable of forming a film substantially impermeable to water vapor, allowing both the adhesion of the primer to the bituminous coating and to said surface of construction work or building by substantially eliminating the risks of blistering.

The subject of the invention is also a sealing and / or circulation coating for a construction or building structure, characterized in that it comprises at least one layer of adhesion primer as defined above, applied to the surface of the construction work or building to be protected, said surface constituting a polar support and at least one layer of bituminous coating deposited on said primer layer (s). Finally, the invention also relates to a method for sealing and / or providing a circulation coating for a construction or building structure, characterized in that at least one layer of an adhesion primer is deposited such as defined above, on the surface intended to be sealed and / or provided with a circulation coating, said surface constituting a polar support then in that at least one layer of bituminous coating is deposited on said layer (s) ( s) primary. The inventors have shown, quite surprisingly, that a primer based on such a (co) polymer allows satisfactory adhesion of both the primer itself on a polar support such as concrete or metal, and bituminous coating on said primer, avoiding blistering phenomena, the primer playing here a role of the "bonding or bonding intermediate" type between the polar support and the bituminous coating. The urethane polymers or copolymers with pendant polar groups are examples of the (co) polymers useful for the purposes of the invention. ''

They are commonly used in the composition of inks, parquet varnishes, paints, lacquers and coatings for wood, metal, concrete, plastics, etc. They then have an aesthetic role, a protective role or serve to improve the cleaning of surfaces or to confer a certain resistance to

Abrasion. Furthermore, the use of polyurethanes having pendant acid groups, in dispersion, was already known in the field of printing inks, and it was known that the free acid groups could be used for crosslinking or for adhesion of the coatings formed. based on these dispersions.

However, such polymers have never been used in adhesion primers for bituminous coatings and their ability to eliminate the risks of blistering as well as their role as "bonding or bonding intermediary" for bituminous coatings. on polar supports had never been highlighted.

The adhesion primer according to the present invention contains at least one polymer or copolymer, in particular urethane, the chain of which has at least one grouping during polar, and able to form a film on a support constituted by the surface of a construction or building work intended to be protected.

This surface is generally based on material such as for example concrete, cement mortar and / or metals and constitutes a polar support.

According to the invention, the pendant polar group can consist of an anionic group such as a carboxylic or sulfonic acid group. These groups may be present in the polymer or copolymer used, in particular commercially available, but polymers may also be used by external emulsification, using emulsifying agents (surfactants). However, according to the invention, polymers or copolymers with internal emulsification are preferred.

Such (co) polyurethanes are known in the art and can in particular be obtained by replacing the polyol constituent, or only a part of it, depending on the number of acid groups desired, with a monomer containing an acid group (carboxylic or sulfonic). while.

The anion centers are then generated before the (co) polymer is put in the form in particular of dispersion.

The number of polar groups is advantageously chosen so that the primer has a good affinity with polar supports and that the polarity of the film is relatively low on the surface, once formed. It advantageously corresponds to an acid number between 5 and 50. The basic structure of the (co) polymer used is relatively unpolar. It is advantageously compatible and refines with the bituminous coating.

According to the invention, the term “bituminous coating” means a coating produced from bituminous sheets and / or from poured asphalt, or else the bituminous coatings conventionally used for forming a wearing course, such as bituminous mixes. The polymer or copolymer used can advantageously consist of an aliphatic polyurethane with a polyester chain, an aromatic polyurethane with a polyether chain or a polyurethane acrylic copolymer. Polyester chain aliphatic polyurethanes are particularly preferred.

The molecular mass of these polymers or copolymers is preferably greater than 1 million.

The primer according to the invention comprises at least one polymer or copolymer as defined above in the form of a solution or a dispersion.

The Broo field viscosity of the solution or dispersion, measured at 25 ° C, is advantageously between 20 and 500 Pa.s.

It can advantageously be a solution in a solvent other than water, in particular in a solvent chosen from hydrocarbons, aromatic solvents, acetates or mixtures of these.

The (co) polymer is dissolved, preferably at a rate of 25 to 50% of dry extract. According to another embodiment of the invention, it is a dispersion in water, in another non-solvent medium of the (co) poly ere or in a mixture of these. The primer of the present invention preferably comprises a dispersion of the (co) polymer in water, in particular for applications on a concrete support.

Preferably, this comprises between 25 and 50% of (co) polymer and has a pH between about 7 and 10.

The polymer or copolymer is advantageously insensitive to water.

In addition, this (co) poly era must be substantially non-thermoplastic at the temperatures at which bituminous coatings are used, in particular below 150 ° C. ι

According to alternative embodiments of the invention, the primer can comprise a mixture of (co) polymers as defined above or a mixture of at least one of said polymers with one or more other (co) polymers such as for example (co ) acrylic polymers.

The primer according to the invention forms a slightly polar film substantially impermeable to gases and in particular to water vapor, unlike known bituminous primers.

The primer according to the invention is intended to be used for the protection of substrates, in particular concrete, construction works or buildings. It can be implemented according to conventional coating techniques.

It makes it possible to eliminate the risks of blistering encountered with the primers used until now, at the level of the primary itself before receiving the bituminous coating as during the realization of this one, as well as at the level of the bituminous coating once in place. It should also be noted that the primers according to the invention have other advantageous characteristics compared to those usually used, namely: - compared to epoxy resins, to be single-component and not to require the incorporation of sand on the surface , delicate operation on surfaces close to the horizontal and practically impracticable on strongly inclined or vertical surfaces, ^_ compared to bituminous solutions, to contain very little or no solvents and to be non-flammable,>

- compared to both bituminous solutions and bituminous emulsions, to be practically colorless and therefore very slightly dirty for the work environment, and easily stainable using in particular dyes or pigments which are fixed in a preferred manner in solvent (or dispersing liquid), or in the polymer. The primer according to the invention is particularly well suited for the production of bridge decks or certain high traffic roads, since this adhesion primer can in particular lead to total adhesion of the bituminous coating to the support, which makes it possible to satisfy d 'all the better for the resistance requirements of such road surfaces to deformation and to horizontal forces, in particular of fining.

It should be noted in this regard that, in the current technique, it is common to put in place the wearing course so that it does not adhere to the support (this is the case in particular of the lanes reserved for buses), to avoid the blistering phenomenon. On the contrary, the primer according to the invention is particularly advantageous because of the adhesion of the coating to the support that it provides, this latter being able in particular to eliminate the risks of rut formation or even to improve the resistance to shocks.

To achieve the sealing of a building or a construction work, in particular a bridge deck, and / or provide the latter with a traffic coating, at least one layer of the adhesion primer is deposited as as defined above on the support most often made of concrete, then the bituminous coating is produced in a conventional manner, according to one or more superposed layers.

The coating formed on the support using the primer according to the invention can constitute a simple waterproofing coating, for example when it is applied to a building surface, in particular a roof or a terrace, this coating then comprising a bituminous membrane and / or a layer of poured asphalt. In the case of a traffic lane, the bituminous coating formed using the primer according to the invention may possibly be intended to receive another coating, such as a wearing course, or in other cases, it can constitute a waterproof wearing course (for a bridge deck for example).

The invention is described in more detail using the examples given below by way of illustration and not limitation as well as tests demonstrating the properties of the adhesion primers according to the invention with reference to the figure schematically representing a blistering test device. EXAMPLES

The primaries listed below are used for their lack of sensitivity to water:

- primary A: known bituminous solution with 50% dry extract in a toluene-xylene mixture

- primary B: dispersion in water of aliphatic polyurethane with 32% dry extract, according to the invention

- Primary C: dispersion in water of an acrylic aliphatic urethane copolymer with 35% dry extract, according to the invention s

- primary D: dispersion in water of an acrylic urethane aromatic copolymer with 33% of dry extract, according to the invention - primary E: solution of aromatic polyurethane in xylene, with 40% of dry extract and viscosity Brookfield, measured at 25 "C, 75 mPa.s, according to the invention.

TACKLING TEST

The test is carried out using the device 1 illustrated in the appended figure.

It consists in covering one side of a fiber cement plate 2 with a layer of the primer 3 to be tested and then, after drying of the latter, in welding a bituminous waterproofing sheet 4.

This plate is then subjected, using pliers 5 for example, provided with a seal 6, to a cup 7 containing water 8, as a cover, the uncoated side of the plate being contact with the air in the cup 7. The assembly is placed in a heated enclosure 10 and brought to increasing temperatures from 10 ° C to 10 ° C for consecutive periods of 24 hours.

In the figure, we see a sealing sheet having blistered.

The temperatures of appearance of the blistering of the bituminous sheet 4 at the surface of the fiber cement plate 2 are measured. This makes it possible to globally compare the behavior of different primers with respect to the risk of blistering. Indeed, the saturated vapor pressures inside the cup 7, tending to peel off the sheet 4, are increasing with the rise in temperature. In addition, during this test, one can also assess the thermal susceptibility of the primers linked to their possibly thermoplastic nature.

The results obtained are given in Table 1 below:

Table 1

Primary I Nothing! Nothing Nothing Nothing Nothing! Lightweight

E i II blistering PERPENDICULAR TRACTION TEST

The test is carried out by installing a welded or hot-cast waterproofing coating on the surface of a cement concrete plate with the interposition of the primer to be tested, after it has dried.

A metal patch is then bonded to the coating which is cut to the concrete around the patch. A traction is then exerted on the pellet at a speed of 3 mm / min and the force R necessary for tearing it off is noted, as well as, if necessary, comments on the mode of detachment.

The results obtained are given in the following tables:

- Table 2 corresponds to the behavior of the primers under a sanded asphalt poured at 230 ° C in a layer 12 mm thick;

- Table 3 corresponds to the behavior of the primers under an asphalt poured at 210 "C in 10 mm thickness;

- Table 4 corresponds to the behavior of the primaries under a bituminous sheet;

- Table 5 corresponds to the behavior of primers under a bituminous sheet, the concrete then being replaced by a galvanized sheet metal plate. Table 2 Table 3

Poured asphalt Asphalt poured at 230 ° C - at 210 ° C - Thickness 12 mm Thickness 10 mm

without 3.2 bars 10 bars Numerous primary bubbles in the asphalt

Primary 7 bars Bubbles in

At the asphalt

Primary 4, 1 bar> 15 bar D

Table 4 Bituminous sheet welded by flame on concrete slab

Without primary 4.7 bars

Primary A 3, 8 bars

Table 5 Bituminous sheet flame welded on sheet metal

Primary D 1.2 bar \ Break in plane Metal peel / primary

It is found that the primers according to the invention eliminate the risks of blistering without reducing adhesion, or even improving it.

Claims

1 / Adhesion primer for bituminous waterproofing and / or circulation coating, intended to be applied to a surface of a construction or building structure prior to said bituminous coating, said surface constituting a polar support, characterized in that it comprises at least one polymer or copolymer in solution or in dispersion, of relatively weakly polar basic structure and whose chain has at least one group during polar, said polymer or copolymer being capable of forming a film substantially impermeable to vapor of water, allowing both the adhesion of the primer to the bituminous coating, and to said surface of construction work or building by substantially eliminating the risks of blistering. 2 / adhesion primer according to claim 1, characterized in that it comprises a urethane polymer or copolymer.

3 / adhesion primer according to claim 2, characterized in that it comprises an aliphatic polyurethane with polyester chain.

4 / adhesion primer according to claim 2, characterized in that it comprises an aromatic polyurethane with polyether chain.

5 / adhesion primer according to claim 2, characterized in that it comprises an acrylic polyurethane copolymer.

6 / adhesion primer according to any one of the preceding claims, characterized in that the polymer or copolymer has a molecular weight greater than 1 million.

7 / adhesion primer according to any one of the preceding claims, characterized in that the group during polar is an anionic group. 8 / adhesion primer according to claim 7, characterized in that the pendant anionic group is a carboxylic or sulfonic acid group.

9 / adhesion primer according to claim 7 or 8, characterized in that the number of pendant anionic groups corresponds to an acid number between 5 and 50.

10 / adhesion primer according to any one of the preceding claims, characterized in that said polymer or copolymer is in the form of a dispersion in water.

11 / adhesion primer according to any one of the preceding claims, characterized in that the content of (co) polymer (s) is between 25 and 50% of dry extract.

12 / Sealing and / or circulation coating for construction or building work, characterized in that it comprises at least one layer of adhesion primer as defined according to any one of claims 1 to 11 applied to the surface of the construction or building structure to be protected, said surface constituting a polar support, and at least one layer of bituminous coating deposited on said primer layer (s). 13 / coating according to claim 12, characterized in that it is applied to a surface forming a taxiway, in particular a bridge deck, and in that the bituminous coating layer is a wearing course or a covered sealing layer a wearing course.

14 / coating according to claim 12, characterized in that it is applied to a building surface, in particular a roof or a terrace, and in that the bituminous coating layer is a sealing layer comprising a bituminous membrane and / or a layer of poured asphalt.

15 / coating according to any one of claims 12 to 14, characterized in that it is applied to a surface comprising concrete, cement mortar and / or metals.

16 / A method for sealing and / or providing a circulation coating for a construction or building structure, characterized in that at least one layer of an adhesion primer is deposited according to any one of claims 1 to 11 on the surface intended to be sealed and / or provided with a circulation coating, said surface constituting a polar support, then in that at least one layer of bituminous coating is deposited on said layer (s) of primary.