WO2007131895A1

WO2007131895A1 - Method for filling in building joints

Info

Publication number: WO2007131895A1
Application number: PCT/EP2007/054350
Authority: WO
Inventors: Stefan Coppus
Original assignee: Tremco Illbruck Productie B.V.
Priority date: 2006-05-12
Filing date: 2007-05-04
Publication date: 2007-11-22
Also published as: DE112007001079A5; EP2021390A1

Abstract

The invention relates to a method for filling in building joints using a PU-based foam material applied using a spray can, wherein the foam material is isocyanate-free and preferably obtained as per WO 02/066532 A1, wherein the foam material after the application has a first phase of considerable expansion and then a second phase in which there is no longer significant expansion, followed by a third phase in which there is still no hardening but a skin forms which is so strong that in the case where foam material is removed damage is caused to the surface of the foam material which cannot be satisfactorily repaired, and finally there is the hardening phase. In order to provide a method for filling in building joints which can be applied reliably and efficiently and which avoids one or more of the disadvantages identified above, it is proposed that excess foam material is removed in the second phase by means of a preferably spatula-like tool.

Description

Method for filling construction joints

The invention relates to a method for filling construction joints by means of a PU-based, auszubringenden from a spray foam, wherein the foam is isocyanate-free, preferably according to one of the embodiments as disclosed in WO 02/066532 Al, wherein the foam after deployment has a first phase of significant post-expansion and then a second phase in which there is no significant expansion, followed by a third phase in which there is still no curing, but such a strong skin formation that it is not at a removal of foam sufficient healing destruction of the foam surface comes until finally the curing occurs.

Such foams are, as already stated, known from WO 02/066532 A1. The disclosure content of this document is hereby incorporated in full content, also for the purpose of incorporating features of this document into the claims of the present application.

Larger heads, especially vertical Baufugen, conventionally lent with joint sealing tapes, preferably those based on a impregnation of expanding open-cell foam filled. The requirements for such joint fillings are laid down, for example, with regard to the Federal Republic of Germany in DIN 18542. The joint sealing tapes are usually delivered in compressed form in roll form. The user rolls off a strip length sufficient for the joint and removes the covering paper from the self-adhesive strip located on the joint strip. The sealing tape is then attached in the still compressed state by means of the self-adhesive layer within the joint on the building and fills after a time, according to the shared expansion, the joint completely. By means of such joint sealing strips is a desired good, also in terms the outer appearance advantageous, filling the gap achieved. The ecological and toxicological safety is also sufficient. The disadvantage, however, is that a joint sealing strip of certain thickness can be used only for a joint of a certain width range for sealing. For given on a building joints joints of different joint widths must therefore be held up synonymous sealing strips of different thickness. In addition, there may be problems due to insufficient sealing in the area of outbreaks in strongly irregular joints, for example in the field of old building renovation, which then have to be plastered in an additional operation. Another disadvantage is the production relatively expensive conversion when using different color types, which is only profitable for large amounts of foam.

It has already been proposed to use conventional PU foam for filling such joints. Due to the post-expansion and the fact that an exact filling of a joint in the desired manner with the foam is not always possible anyway, it is necessary, however, thereafter to remove the foam present in excess. Due to the nature of conventional foams, this is only possible with great difficulty. Incidentally, the appearance resulting from such processing is not optically acceptable. The lack of applicability for this purpose is also determined by the property of conventional PU prepolymers to crosslink during the curing process by reaction with water to release CO ₂ . This gas evolution leads to a long period in which the foam can expand and escape from the joint. Also, conventional PU foam is not UV stable in the desired manner. There is a rapid discoloration or embrittlement of the foam. Also, conventional PU can foams do not have the necessary flexibility to be able to compensate for joint movements, as in practice, for example, due to climatic changes. occur. In addition, there may be toxicological concerns.

On this basis, the object is to provide a method for filling Baufugen that is safe and efficient to use in avoiding one or more of the above-mentioned disadvantages.

This object is achieved in the subject matter of claim 1, wherein it is pointed out that within the second phase by stripping, for example by means of a spatula in excess existing foam is removed.

Surprisingly, it has been found that canned foams according to the cited publication WO 02/066532 pass through a phase after introduction into the joint and a first post-expansion phase in which no or virtually no post-expansion occurs any more. Further, it was surprisingly found that in this state of the foam, which is also to circumscribe creamy, in a simple manner by means of a spatula or similar tool in excess in or out of the joint foam located safely and professionally can be easily removed. It is essential that the said time period is used for this purpose.

Also advantageous is the ease of handling as moisture-curing one-component system. The aforementioned smoothing or leveling by means of a spatula-like tool leads to an optically advantageous joint closure. In the course of removing excess foam, it is also possible at the same time to smooth the joint surface.

Specifically, it has been found that foamed mixtures of alkoxysilane-terminated prepolymers, as are characteristic of the foam, as mentioned at the beginning, in the first approx. 1 to 8, generally 3 to 6, more precisely approx. 5 Min after spreading out of the spray can by the leakage of propellant gases still tend to expand and are completely stable to volume after this short-lived initial expansion. This - second - phase of volume stability is also sufficiently long, that until the onset of severe skin formation, which leads to non-healing destruction, you want to remove foam here, enough time is given to remove excess foam. The second phase extends for 2 to 20 minutes, preferably 5 to 15 minutes, more preferably 10 to 15 minutes. This period of time can be influenced by a corresponding adjustment of the foam formulation. The period of time in which the described removal of excess foam is suitably carried out is referred to as the processing time. A certain stickiness is already given here. It is therefore possible that the processing time already includes such a state of the foam, in which, for example, after pressing a wooden stick and pulling out the wooden stick threads are pulled. The main criterion is skin formation. This must not be so strong that by removing excess foam such damage occurs that results in an ugly appearance of the joint or even due to no longer given sufficient replication of the skin can be leaking. Also, the foam formulation can be influenced so that the third phase can be varied over time. For example, in a period of 5 to 60 min.

It is also of particular importance that when the foam excess is removed in the second phase mentioned above, a skin immediately forms again at the removal regions, ie, as it were, a self-healing effect of the foam can be produced. This skin is essential for the later desired tightness of the joint. By suitable choice of UV stabilizers or selection of aliphatic isocyanates as starting material for the end-capped PU prepolymers, a permanent UV stability can be ensured. By appropriate selection of the polynols according to the respective chain length, it is possible to achieve a flexibility of the foam which takes into account the possible movements of the construction seams. The addition of cell-opening substances leads to a decrease in the μ value of the foam, so that it can be adjusted according to the application of vapor diffusion. Accordingly, with less or no addition of such substances, a setting can be achieved up to vapor diffusion closed.

The foamed on the outer sides of foam adheres well to the joint edges and is up to the example, according to the standards required in the Federal Republic of Germany 600 Pa driving rain and wind-tight. The so-called a value is less than 0.1.

Adhesion promoters can also be admixed to improve adhesion to special surfaces. The reactivity of the α-aminoalkylated alkoxysilanes used is high enough relative to the air humidity to achieve a sufficiently rapid curing of the foam as a one-component system.

By adding flame retardants, as they are basically known for PU foams, a flame retardant adjustment of the foam can be achieved.

The foam located in the spray can initially consists of a prepolymer which represents the crosslinkable polymer. Further preferred is a foam stabilizer and / or a cell opener and / or a dye and / or a catalyst and / or a solvent and / or propellant gas, if appropriate the latter as a mixture of different propellant gases, contained in the spray can. The foam stabilizer may in this case be present in a proportion of 0.5 to 10, preferably 1 to 3, more preferably 1.5 to 2.5%. The cell opener in a proportion, which is to be understood here in each case as weight fraction, from 0.1 to 1, preferably 0.2 to 0.4, more preferably 0.3 to 0.35 wt .-% may be included. The dye may be contained in a proportion of 0.1 to 2, preferably 0.1 to 1%, more preferably 0.1 to 0.2 wt .-% and more preferably about 0.15 wt .-% , The catalyst may be contained in a range of 0.2 to 1.2, preferably 0.3 to 0.5, more preferably about 0.46 wt .-%.

The solvent may be contained in a range of 1 to 8%, preferably 1.5 to 3%, more preferably about 2.1% by weight.

The propellant gas, which may also be composed of a plurality of components, may preferably be in a range of 10 to 30 wt%, more preferably in a range of 15 to 20 wt%, further preferably in a range of 18 to 20, most preferably in a range of about 18.5% by weight in the spray can.

It has been found that with the foam described here filled and in the manner described then in terms of excess foam processed joints in particular can also be expansion joints, which can change over time in their width of up to 30% due to temperature changes or similar processes over time , In any case, for joints that vary in width by up to 15% over time.

Exemplary embodiments:

1. Preparation of an MDI based prepolymer: 500 g of methyl diisocyanate are placed under nitrogen at 80 ° C. A mixture of 207.3 g of a trifunctional polypropylene glycol having a molecular weight of 3000 g / mol, 259.1 g of a bifunctional polypropylene glycol having a molecular weight of 400 g / mol and 27.6 g of 1,6-hexanediol (M = 118.2 g / mol) are within 2 h added dropwise with vigorous stirring. The mixture is stirred for a further hour at 85 ° C. and then 86.4 g of vinyltrimethoxysilane (Geniosil XL 10 from Wacker) are added together with 1.73 g of DMDEE. Finally, 480.5 g of N-phenylaminomethyl-methyldimethoxysilane (Geniosil XL 972 from Wacker) are added dropwise within 1.5 h and the mixture is stirred for a further 1 h. The IR spectrum of the mixture obtained shows no NCO band more, so that it can be assumed that a complete reaction of the isocyanates. The viscosity of the prepolymer is 40.9 Pas (cone-plate vikosimeter, 50 ° C).

Preparation of an H12-MDI Based Prepolymer:

600 g of H12-MDI and 0.6 g of DMDEE are placed under nitrogen at 90 ° C. A mixture of 307.2 g of a bifunctional polypropylene glycol having a molecular weight of 400 g / mol, 245.8 g of a trifunctional polypropylene glycol having a molecular weight of 3000 g / mol and 32.8 g of 1,6-hexanediol

(M = 118.2 g / mol) are added dropwise within 2 h with vigorous stirring. The mixture is stirred for a further hour at 90 ° -95 ° C. and then 102.4 g of vinyltrimethoxysilane (Geniosil XL Iß from Wacker are added.) Finally, 602.5 g of N-phenylaminomethyl-methyldimethoxysilane (Geniosil XL 972 from Wacker) are added dropwise within 1.5 h and then 0.15 g

DBTDL added. The mixture is then stirred for a further 2 h. The absence of the NCO band in the IR spectrum of the mixture demonstrates the termination of the reaction. The viscosity of the prepolymer is 13.5 Pas (cone-plate viscometer, 50 ° C). 3. aerosol can filled with a prepolymeric mixture:

The prepolymer mixture according to Example 1 is mixed together with the following components in an aerosol can with pressure valve and then charged with the listed propellant gases.

Component Effect Wt.%

Prepolymer 1. Crosslinking polymer 77.4%

RC-PUR Rod 340 foam stabilizer 2.00%

Ortegol 501 cell opener 0.31%

Reactint black X77 dye 0.15%

Butyl phosphate catalyst 0.46%

Ethyl acetate solvent 2.08%

Propane / i-butane (40:60) propellant 14.1%

Dimethyl ether propellant 3.5%

The light gray foam sprayed into a 30 mm wide joint (joint depth: approx. 40 mm) can be machined over a period of 5 minutes to 10 minutes, after which the foam is tack-free and does not push out of the joint. After curing, a semi-rigid flexible foam is obtained, which fills the gap to the edge. By means of an apparatus simulating a movement joint with maximum deflections in the transverse direction of ± 15%, no foam breakage was observed within 2000 cycles. The μ value of the material, measured according to DIN EN ISO 12572, was <100. The rainfall density, measured according to DIN 18542BG 1, resulted in a tightness of> 600 Pa, the air permeability an a value of <0, lm ³ / hm (daPa) ⁿ . A compatibility test with adjoining conventional building materials (concrete, brick, sand-lime brick, white PVC, wood) revealed no migration tendencies at elevated temperatures (tested up to 80 ° C). Since no plasticizers are used and all components involved are incorporated into the crosslinked polymer matrix In contrast to impregnated sealing tapes, no migration of the impregnate is possible.

4. Aerosol can filled with a prepolymer mixture:

The prepolymer mixture from Example 2 is mixed together with the following components in an aerosol can filled with pressure valve and then charged with the listed propellant gases.

Component Effect Wt.%

Prepolymer 2. Crosslinking polymer 77.55%

RC-PUR Rod 340 foam stabilizer 2.00%

Ortegol 501 cell opener 0.31%

Butyl phosphate catalyst 0.46%

Ethyl acetate solvent 2.08%

Propane / i-butane (40:60) propellant 14.1%

Dimethyl ether propellant 3.5%

The foam sprayed into a 30 mm wide joint (joint depth: approx. 40 mm) can be machined within a period of 5 min - 12 min

Foam free and no longer pushes out of the joint. After curing, you get a soft flexible foam that fills the gap to the edge. By means of an apparatus simulating a movement joint with maximum deflections in the transverse direction of ± 15%, no foam crack was observed within 2000 cycles. The μ value of the material, measured according to DIN EN ISO 12572, was <100. The driving rain and air permeability fulfilled as in 3. the criteria of the construction standard. The compatibility test with adjacent customary building materials did not reveal any incompatibilities. To check the UV stability, a sprayed-out bead of the (pure white) foam was exposed for 2 weeks to UV light having an irradiance of 765 W / m ^2. emits (2.2 kVA xenon lamp). The foam showed no discoloration or embrittlement after treatment.

As a removal tool over excess foam, a common masonry spatula was used. Also possible is the deduction by means of a corresponding wooden part and / or a knife, but the knife is not used in a conventional manner knife-like so in the form of cutting movements, but in terms of a peel, as in a spatula.

All disclosed features are (in themselves) essential to the invention. The disclosure of the associated / attached priority documents (copy of the prior application) is hereby also incorporated in full in the disclosure of the application, also for the purpose of including features of these documents in claims of the present application.

Claims

1. A method for filling construction joints by means of a PU-based foam auszubringenden from a spray can, wherein the foam is isocyanate-free, and preferably according to WO 02/066532

Al is obtained, wherein the foam after application has a first phase of significant post-expansion and then a second phase in which no significant expansion is given, followed by a third phase in the still no curing, but such a strong skinning is given that at a removal of foam to insufficiently healing destructions of the foam surface comes, until finally the curing occurs, characterized in that excess foam is removed in the second phase by means of a preferably spachtiförmigen tool.

2. The method according to claim 1, characterized in that at the same time a smoothing of the surface is carried out in the course of removing the foam present in excess.