WO2009071470A1

WO2009071470A1 - Single-component polyurethane adhesive

Info

Publication number: WO2009071470A1
Application number: PCT/EP2008/066177
Authority: WO
Inventors: Hans-Jürgen Reese; Sylvia Krawczyk; Stefan Ullmann
Original assignee: Basf Se
Priority date: 2007-12-03
Filing date: 2008-11-26
Publication date: 2009-06-11
Also published as: EP2220138A1; KR20100094541A; RU2010127150A; JP2011505481A; CN101883805A

Abstract

The present invention relates to a method for gluing objects, wherein an adhesive mixture comprising an isocyanate group that can be obtained by mixing a) polyisocyanates with b) high-molecular compounds having groups reactive to isocyanate, c) expanding agents, d) foam-regulating additives, e) catalysts, and f) optionally other additives, wherein polyisocyanate a) is used in amounts such that more isocyanate groups than groups reactive to isocyanate are present in the mixture, is applied from a pressure tank to at least one object to be glued, wherein the foam-regulating additives (d) comprise silicon oil, and the adhesive mixture is applied immediately after expanding due to pressure drop.

Description

Einkomponentenpolyurethanklebstoff

The present invention relates to methods for bonding objects in which an isocyanate-containing adhesive mixture obtainable by mixing a) polyisocyanates with b) higher molecular weight compounds with isocyanate-reactive groups, c) blowing agents d) foam-regulating additives, e) catalysts and f ) optionally other additives, polyisocyanates a) being used in amounts such that the mixture contains more isocyanate groups than isocyanate-reactive groups, from a pressure vessel onto at least one object to be bonded, the foam-regulating additives (d) silicone oil and the adhesive mixture is applied so that it is applied immediately after relaxing by pressure drop on the adhesive surface.

Further embodiments of the present invention can be taken from the claims, the description and the examples. It goes without saying that the features mentioned above and those still to be explained below of the article according to the invention can be used not only in the respectively indicated combination but also in other combinations without departing from the scope of the invention.

One-component polyurethane foams made from aerosol containers are frequently used in the field of construction for the installation of windows and doors in buildings as well as filling material for building-related cavities or wall penetrations for pipe installations. Such an aerosol container includes an NCO-terminated polyurethane prepolymer as well as propellants and additives. By discharging the contents by means of propellant and the subsequent foaming and curing with atmospheric moisture, the desired foam is formed. Mainly, these foams are used as mounting foam. A big advantage of such mounting foams is their easy handling.

Such a one-component mounting foam is described for example in WO 2005/054324. In addition to use as mounting foam, for example, for mounting windows and door frames or for filling cavities, this can also be used as a spray adhesive. In this case, for example, insulation boards and roofing are glued together or with a substrate.

A disadvantage of using known one-component mounting foams as adhesives is that they tend to rub off after application. This refers to the subsequent formation of gas bubbles in the adhesive joint, which means that the objects to be bonded do not remain at their predetermined position. In particular, when bonding insulation boards on the outer facades of buildings so unevenness can occur on the finished building facade. The object of the present invention was therefore to provide an easy-to-use adhesive mixture, in particular for the construction industry, which enables an optimal alignment of the elements to be bonded. In particular, it was an object of the present invention to provide a method for bonding objects, wherein the adhesive mixture does not aggravate.

Surprisingly, the object according to the invention is achieved by a process for bonding articles in which an isocyanate-containing adhesive mixture obtainable by mixing a) polyisocyanates with b) relatively high molecular weight compounds with isocyanate-reactive groups, c) blowing agents d) foam-regulating additives, e) catalysts and f) optionally other additives, polyisocyanates a) being used in amounts such that the mixture contains more isocyanate groups than isocyanate-reactive groups, from a pressure vessel to at least one object to be bonded, wherein the foam-regulating additives (i.e. ) Silicone oil and the adhesive mixture is applied so that it is applied immediately after relaxing by pressure drop on the adhesive surface, dissolved

An adhesive mixture according to the invention is applied from a pressure vessel to the objects to be bonded. In this case, the adhesive mixture can be applied solely by the pressure prevailing in the aerosol can internal pressure on the objects to be bonded. This internal pressure is generated by evaporation or expansion of the propellant gas mixture. Alternatively, it is possible to discharge the inventive adhesive mixture with the aid of gases under pressure, for example compressed air, from the aerosol can and apply it to the adhesive surface of the objects to be bonded. It is essential to the invention that the foam-regulating additives (d) contain silicone oil and the adhesive mixture is applied immediately after relaxing by pressure drop. This is the case, for example, when an adhesive mixture according to the invention is applied from a pressure vessel with the aid of a metering gun. In such a metering gun, the content of the entire gun is under the pressure that also prevails in the pressure vessel. If the contents of the pressure vessel are to be discharged, a valve opens at the outlet of the gun, at which essentially the pressure drop to external pressure takes place. The effect according to the invention is not achieved if, after the pressure drop has occurred, for example, the adhesive mixture is first passed through a metering tube.

Suitable polyisocyanates are, for example, aliphatic, cycloaliphatic and in particular aromatic di- or polyisocyanates. Specific examples which may be mentioned are: aliphatic diisocyanates, such as hexamethylene diisocyanate 1, 6, 2-methylpentamethylene diisocyanate 1, 5, 2-ethyl-butylene-diisocyanate-1, 4 or mixtures of at least 2 of those mentioned C6 alkylene diisocyanates, pentamethylene diisocyanate-1, 5 and butylene diisocyanate 1, 4, cycloaliphatic diisocyanates, such as 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane (isophorone diisocyanate), 1,4-cyclohexane diisocyanate, 1-methyl-2, 4- and -2,6-cyclohexane diisocyanate and the corresponding isomer mixtures, 4,4'-, 2,4'- and 2,2'-dicyclohexylmethane diisocyanate and the corresponding isomer mixtures and preferably aromatic diisocyanates, such as 1, 5-naphthylene diisocyanate (1,5-NDI), 2,4- and 2,6-toluene diisocyanate (TDI) and mixtures thereof, 2,4'-, 2,2'- and preferably 4,4 ' Diphenylmethane diisocyanate (MDI) and mixtures of at least two of these isomers, polyphenyl polymethylene polyisocyanates (polymeric MDI, PMDI) with two or more aromatic systems, mixtures of PMDI and toluene diisocyanates, polyphenyl polyisocyanates, urethane-modified liquid 4, 4'- and / or 2,4-diphenylmethane diisocyanates and 4,4'-diisocyanato-diphenylethane (1, 2).

If appropriate, polyisocyanates a) may also be isocyanate prepolymers or low-monomer isocyanates, as described, for example, in EP 1 518 874, WO 2005/054324 or DE 103 11 607.

As Isocyanatprepolymere at least one di- and / or polyisocyanate and / or a reaction product of the reaction of at least one isocyanate-reactive compound with at least one di- and / or polyisocyanate can be used, wherein the preparation of these prepolymers having isocyanate groups can be carried out by generally known methods , As the reaction product having isocyanate groups, a prepolymer having an NCO content of 4 to 30% is preferably used.

In particular, the polyisocyanate a) used is a PMDI, preferably having a viscosity at 25 ^° C. of less than 600 mPas, more preferably from 100 to 400 mPas and particularly preferably from 150 to 300 mPas. In particular, a crude MDI containing 35 ± 17 wt%, 2-core MDI, 26 ± 6 wt% 3-core MDI, 12 ± 4 wt% 4-core MDI, 5 ± 3 wt. -% 5-core MDI and 23 ± 10 wt .-% 6- and more highly nuclear MDI used.

As higher molecular weight compounds with isocyanate-reactive groups b) it is possible to use customary compounds having isocyanate-reactive groups. Preference is given to using polyetherols and / or polyesterols, in particular exclusively polyetherols.

Polyetherols according to the invention are prepared by known processes, for example by anionic polymerization with alkali metal hydroxides or alkali metal alkoxides as catalysts and with the addition of at least one starter molecule which contains 2 to 4 reactive hydrogen atoms bound, or by cationic polymerization with Lewis acids, such as antimony pentachloride or boron fluoride. Etherate from one or a plurality of alkylene oxides having 2 to 4 carbon atoms in the alkylene radical. Suitable alkylene oxides are, for example, tetrahydrofuran, 1,3-propylene oxide, 1,2- or 2,3-butylene oxide and preferably ethylene oxide and 1,2-propylene oxide. Further, as catalysts, it is also possible to use multimetal cyanide compounds, so-called DMC catalysts. The alkylene oxides can be used individually, alternately in succession or as mixtures. Preference is given to mixtures of 1, 2-propylene oxide and ethylene oxide, wherein the ethylene oxide is used in amounts of 10 to 50% as ethylene oxide endblock ("EO-cap"), so that the resulting polyols have over 70% primary OH end groups ,

As a starter molecule, water or 2, 3 and 4-valent, preferably 3-valent alcohols, such as glycerol, trimethylolpropane, ethanolamine, diethanolamine, triethanolamine and other trihydric alcohols or amines having three active hydrogen atoms into consideration.

The polyether polyols, preferably polyoxypropylene-polyoxyethylene polyols, have a functionality of 2 to 4, preferably 2.5 to 3.5 and more preferably 2.6 to 3.4 and number average molecular weights of preferably 600 to 8,000, most preferably preferably of 1,000 to 6,000 and in particular from 1000 to 4000 g / mol.

Preferably, as higher molecular weight compounds with isocyanate-reactive groups b) a mixture of a trifunctionally started polyetherol having a number average molecular weight of 4000 ± 2000 g / mol (b1), a trifunctionally started polyetherol having a molecular weight of 1000 ± 200 g / mol (b2 ) and a difunctionally started polyetherol having a number average molecular weight of 600 ± 100 g / mol (b3). Especially preferred trifunctionally started polyetherol (b1) is a glycerol-initiated polyetherol based on propylene oxide and ethylene oxide, trifunctionally started polyetherol (b2) is a glycerol-initiated polyetherol based on propylene oxide and ethylene oxide and difunctionally started polyetherol (b3) is an ethylene glycol started polyetherol based on ethylene oxide used. The weight ratio of (b1) :( b2) :( b3) is preferably 4 ± 1: 8 ± 2: 1 ± 0.5.

Further, the higher molecular weight compounds having isocyanate-reactive groups b) a brominated polyetherol having a molecular weight of preferably 350 to 1000, more preferably 400 to 600 g / mol and a functionality of preferably 2 to 4 contain. In particular, a bifunctionally and / or trifunctionally started polyol based on ephichlorohydrin, which has been brominated and de-chlorinated, is used as the brominated polyether polyol. Suitable brominated polyetherols are, for example, under the trade name IXOL® from Solvay available. In particular B can be used 251 as brominated Polyetherols IXOL ^® M125 and IXOL®.

Further, the higher molecular weight compounds with isocyanate-reactive groups b) in addition to the polyols mentioned further conventional hydroxy-functional compounds, eg. Example, short-chain diols such as ethylene glycol, propylene glycol, butanediol-1, 4 as chain extenders, short-chain at least trifunctional alcohols such as glycerol or trimethylolpropane as crosslinkers and / or monools as molecular weight regulators. Preferably no chain extenders, crosslinkers or molecular weight regulators are contained.

As propellants can generally known propellants, such. B. substances which have a boiling point under normal pressure in the range of -40 ⁰ C to 120 ⁰ C, gases and / or liquid propellants are used, for example carbon dioxide, alkanes and or cycloalkanes such as isobutane, propane, n- or isobutane , Pentane and cyclopentane, ethers such as, for example, diethyl ether, methyl isobutyl ether and dimethyl ether, nitrogen, oxygen, helium, argon, nitrous oxide, halogenated hydrocarbons, for example dichlorofluoromethane, monofluorotrichloromethane, trifluorotrichloroethane and / or partially halogenated hydrocarbons, for example trifluoromethane, 1, 1- Dichloro-1-fluoroethane, monochlorotetrafluoroethane, monochlorotrifluoroethane, monochlorodifluoroethane, difluoroethane, dichlorodifluoroethane, pentafluoroethane, tetrafluoroethane, dichloromonofluoroethane or mixtures which comprise at least two of the blowing agents exemplified.

The blowing agent is usually added in an amount of 0.5 to 40 wt .-%, preferably 10 to 32 wt .-% based on the weight of the components a) to f).

As foam-regulating additives d), it is possible to use all known foam-regulating additives containing silicone oil. In this case, preferably di- methyl siloxane having a viscosity of 10 to 1000 mPas at 25 ⁰ C. In addition to silicone oil, the foam-regulating additive d) may contain further conventional foam stabilizers and / or paraffin oil. As paraffin oil saturated aliphatic hydrocarbons can be used. Preferably, the paraffin oils used at 25 ⁰ C are liquid. As foam stabilizers, it is possible, for example, to use polyalkylene glycol-polysiloxane copolymers such products from Goldschmidt under the trade name "Tegostab®" and particularly preferably Tegostab® B2219 or TegoStab® BF2270.

The weight of foam stabilizer, silicone oil and paraffin oil is particularly preferably 150 ± 50: 2 ± 1.2: 2 ± 1.2. The proportion of foam-regulating additives d), based on the total weight of components a) to f), is preferably 0.5-5, particularly preferably 1-3% by weight. The proportion of silicone oil, based on the total weight of components a) to f) preferably 0.02 to 0.2 wt .-%.

As catalysts e), which in particular accelerate the reaction between the NCO groups of the diisocyanates and the hydroxyl groups of the polyalcohols, the strongly basic amides which are known and customary according to the prior art, such as, for example, 2,3-dimethyl-3,4,5, 6-tetrahydropyrimidine, tris (dialkylaminoalkyl) -s-hexahydrotriazines, such as. Example, tris (N, N-dimethylaminopropyl) -s-hexahydrotriazine and preferably the usual tertiary amines, such as. For example, triethylamine, tributylamine, dimethylbenzylamine, N-ethyl, N-methyl, n-cyclohexylmorpholine, dimethylcyclohexylamine, di- morpholinodiethylether, 2- (dimethylaminoethoxy) ethanol, 1, 4-diaza-bicyclo- (2,2 , 2) octane, 1-azabicyclo (3,3,0) octane, N, N, N ', N'-tetramethylethylenediamine, N, N, N', N'-tetramethylbutanediamine, N, N, N ', N'-tetramethylhexanediamine-1, 6, pentamethyldiethylenetriamine, tetramethyldiaminoethyl ether, bis (dimethylaminopropyl) urea, N, N'-dimethylpiperazine, 1, 2-dimethylimidazole, di- (4-N, N-dimethylaminocyclohexyl) methane and the like and organic metal compounds such as titanic acid esters, iron compounds such as. For example, iron (III) acetylacetonate, tin compounds, e.g. Tin (II) salts of organic carboxylic acids, for example, tin (II) diacetate, the tin (II) salt of 2-ethylhexanoic acid (tin (II) octoate), tin (II) dilaurate or the dialkyltin (IV) salts of organic carboxylic acids, such as. As dibutyltin (IV) - diacetate, dibutyltin (IV) - dilaurate, dibutyltin (IV) maleate or dioctyltin (IV) diacetate or the like and di-butyltin (IV) - dimercaptide or mixtures with at least two said catalysts and synergistic combinations of strong basic amines and organic metal compounds are used. Particular preference is given to using dimorpholinedietyl ether as catalyst e). The catalysts e) can be used in conventional amounts, for example 0.002 to 5 wt .-%, based on the higher molecular weight compounds with isocyanate-reactive groups b).

As auxiliaries and additives f), for example, fillers, flame retardants, nucleating agents, antioxidants, dyes and pigments, inhibitors, stabilizers against hydrolysis, light, heat or discoloration, inorganic and / or organic fillers, reinforcing agents and / or plasticizers can be used.

Further details of the abovementioned auxiliaries and additives can be found in the specialist literature, for example the monograph by JH Saunders and KC Frisch "High Polymers", Volume XVI, Polyurethanes, Part 1 and 2, published by Interscience Publishers 1962 and 1964, respectively. Kunststoff-Handbuch ", Volume 7, Polyurethane, 3rd edition, 1993, edited by G. Oertel, Carl-Hanser-Verlag, Munich or DE 29 01 774.

To prepare the adhesive mixture according to the invention, polyisocyanates a) with relatively high molecular weight compounds with isocyanate-reactive groups b), Propellants c), foam-controlling additives d), catalysts e) and optionally other additives f) placed in a container, the container sealed and the components a) to f) homogenized, wherein polyisocyanates a) used in relation to isocyanate-reactive groups in excess become.

Preferably, the components a) to f) are each added separately to the pressure vessel, then the pressure vessel is closed and the contents are homogenized, for example by shaking. Alternatively, the reaction of polyisocyanate a) with higher molecular weight compounds with isocyanate-reactive groups b) and catalysts e) can also take place outside the pressure vessel. The reaction product thus obtained is then added together with blowing agents c), foam-regulating additives, d) and optionally other additives f) in the pressure vessel.

The method according to the invention is outstandingly suitable for bonding objects, especially in the field of civil engineering and in particular on mineral substrates. In this case, the adhesive mixture according to the invention shows no slippage in the adhesive joint. Thus, the method according to the invention is particularly suitable for bonding in the area of facades, for example, when applying insulating panels or facade elements on mineral substrate, for example, mortar bricks or other parts of buildings. Thus, the objects remain stuck in the once selected position, whereby an optimal alignment, for example of facade elements, is possible.

In the following, the invention will be explained in more detail with reference to an example.

Preparation of the polyol component

From 330 g of a glycerine-based polyetherol based on propylene oxide and ethylene oxide having a number average molecular weight of 1000 g / mol, 147 g of a glycerol-based polyetherol based on propylene oxide and ethylene oxide having a number average molecular weight of 4000 g / mol, 40 g of a polyethylene glycol with a number average molecular weight 600 g / mol, 60 g of a brominated polyether thertriols having a bromine content of about 31 wt .-%, trade name Ixol ^® B 251 of the FIR ma Solvay, 25 g of a polysiloxane-polyoxyalkylene block copolymer (as foam stabilizer trade name Tegostab ^® B 2219 from Goldschmidt), 0.3 g Polydimethylsi- Loxan, tradename Baysilone ^® M100 from Bayer, 60 g diacetone alcohol, 8 g 2,2-dimorpholinodiethylether as a catalyst and 330 g trichloropropyl phosphate is prepared by mixing a polyol component. Preparation of the adhesive mixture in an aerosol container

In a 1-liter aerosol can 286 g of the described polyol component and 394 g PMDI are filled with a viscosity at 25 ⁰ C of about 200 mPas. The aerosol can is closed with a gun valve. 43 g of dimethyl ether, 27 g of a technical gas mixture of 30% by weight of propane and 70% by weight of butane and finally 79 g of tetrafluoroethane (R134a) are subsequently metered into the aerosol can through the valve.

The content of the can is homogenized by intensive shaking. The onset of the prepolymer reaction causes heating of the aerosol can.

After 24 hours of heat-aging at a maximum of 50 ⁰ C, the Prepolymerisationsreak- tion is completed so far that the content is useful as an adhesive.

Use as 1K adhesive

The aerosol can is screwed onto a foam gun and the contents of the can are homogenized by shaking. By operating the gun, the escaping foam mixture is applied to the surface of the insulating board in the form of a foam strip about 3 cm wide.

The somewhat coarse-bubble collapsing foam is distributed over the surface in strand form so that sufficient bonding is possible. The insulation board provided with adhesive foam is subsequently fixed on the concrete wall. There is no soreness and the insulation board remains in position.

Claims

claims

1. A method for bonding objects in the man

an adhesive mixture containing isocyanate groups, obtainable by mixing a) polyisocyanates with b) relatively high molecular weight compounds with isocyanate-reactive groups, c) blowing agents d) foam-regulating additives e) catalysts and f) optionally other additives, polyisocyanates a) being used in such amounts in that the mixture contains more isocyanate groups than isocyanate-reactive groups,

from a pressure vessel on at least one object to be bonded, characterized in that

the foam-controlling additives (d) contain silicone oil and the adhesive mixture is applied immediately after relaxing by pressure drop.

2. The method according to claim 1, characterized in that the foam-regulating additives d) contain paraffin oil, foam stabilizer and silicone oil.

3. The method according to claim 2, characterized in that the foam-regulating additives d) foam stabilizer, silicone oil and paraffin oil in a weight ratio 150 ± 50: 2 ± 1, 2: 2 ± 1, 2 contain.

4. The method according to any one of claims 1 to 3, characterized in that as higher molecular weight compounds with isocyanate-reactive groups b) a mixture containing a polyether polyol b1) having an average functionality of 2.9 ± 0.4 and a number average molecular weight of 4000 to 600 g / mol and a brominated polyether polyol b2) having a number average molecular weight of 500 ± 100 g / mol.

5. The method according to any one of claims 1 to 4, characterized in that as polyether polyol b1) on a mixture of a glycerol started polyetherol

Base of propylene oxide and ethylene oxide having a number average molecular weight of 4000 ± 2000 g / mol, based on a glycerol-started polyetherol of propylene oxide and ethylene oxide having a number average molecular weight of 1000 ± 200 g / mol, and an ethylene glycol-started polyetherol based on ethylene oxide having a number average molecular weight of 600 ± 100 g / mol.

6. The method according to any one of claims 1 to 5, characterized in that the catalyst contains e) Dimorpholindiethylether.

7. The method according to any one of claims 1 to 6, characterized in that polyisocyanate a) PMDI having a viscosity at 25 ⁰ C of less than 500 mPas.

8. The method according to any one of claims 1 to 7 are glued in the objects on a mineral substrate.

9. The method according to any one of claims 1 to 8, characterized in that facade elements or insulation boards are glued to buildings.