CA2242672A1 - Rapid-foaming foam for prefabricated system building - Google Patents

Abstract

The invention concerns a two-component system for producing polyurethane foams, the system comprising a polyol component A with at least one polyol having a functionality of two or more, water and a catalyst system comprising at least two catalysts, of which at least one can catalyze the reaction of the polyisocyanate with the polyol and/or water and at least one further catalyst can catalyze the trimerization of isocyanate groups. The system further comprises a polyisocyanate component B having at least one polyisocyanate with a functionality 2, the ratio between NCO groups in component B and OH groups in component A being > 1.

Description

RAPID-FOAMING FOAM FOR PREFABRICATED SYSTEM BUILDING

Description This invention relates to an improved and fast-foaming urethane fo~m which is set to be fire-retardant. In particular, the invention relates to an improved reactive two-component foam of the urethane-isocy~u~ type resulting from the reaction of a polyol with an isocyanate. The foam is especially suitable for assembly work in the building trade.
The invention relates further to the application of the foam in assembly work in parhcular in the building trade. e.g. for frames made of pine-wood for example for windows and doors. and solid constructions such as masonrv.
Such foam also has other applications. for example as packaging foam. casting compound and the like.
Pol,vurethane-based utility foams are used in particular in the building trade for assembling door frames or the like to fix the frames in concrete walls for example.
For a usual door frame one uses up to 6 portions of foam which is introduced into the joint between frame and wall and foams up there so as to produce good contact between the two parts, whereupon the foam masses cure into a rigid, dimensionally stable m~tçri~l fixing the frame. The foams can also be used for sealing wall ducts for cables and pipes as well as for insulating purposes.
For all these applications it is important that the foam has good adhesive powerand is fully expandable. Such canned foams can exist as one-component systems (lC) based on an isocyanate-teIminated prepolymer and usually cor,l;~i.,;l-g plastici7-ers, blowing agents, catalyst and foam stabilizers, and optionally further additives.
Curing is based on the reaction between the termin~l isocyanate groups and waterwhich is taken from the ~ o~ clingc.
Altematively. one can also use 1.5C systems which consist of an isocyanate-t~rrnin~te~ prepolymer. a separate, small quantity of glycol and blowing agent.
Finally, one can use ~vo-component foams (2C) which are produced by mixing the liquid components, an isocyanate and a reactive polyol in the presence of a blowing agent, catalyst and foam-stabilizing silicone and optionally further addi-tives.
Two-component foams for assembly work are usually handled in pressure-proof containers, for example aluminum aerosol containers charged with propellant under pressure or packages with a cylindrical chamber whereby the two componentsmust be kept sep~le before use. This can be done by parallel use of two separatecontainers, but also for example by putting one component in an outer container and the second component in an inner container disposed within this outer container, the second container being opened by action from outside on the outer container The content of the second container is then mixed with that of the first container and leads to the desired reaction. When the valve of the outer container is opened the foam exits through the valve under the pressure of the propellant located in the con-tainer. Further, cartridge systems are known in which the two components are passed out of two cartridges located side by side with the aid of pistons into a mixing head and discharged via an application system, for example a spray or joint gun.
After the reactive components have first been mixed, the rnixture must be ap-plied to the application site where it solidifies, sets and develops its a&esive effect.
For assembly purposes one desires for example a fast-curing foam to minimi7e thetime during which the assembled part must be supported. On the other hand one desires a foam which expands to full size in which it then solidifies.
A typical disadvantage of commercial foam systems is that the mixture remains flowable too long and it takes too long for the foam to be fully expanded and thereby become "self-supporting". Part of the resulting foam flows out of the frame and must be cut off after curing.
To remedy this problem one frequently uses additional aids in the form of pre-assembled cardboard strips or the like. Nevertheless, it is in most cases necessary to cut off excess material.
By reason of expected environmental protection regulations it is further desir-able to have a canned foam system which can be introduced into package systems, is of simple structure, easy and inexpensive to produce and environmentally accept-able.

Canned foarns currently on the market are nonnally of the urethane type (PUR~
and typically have an ~CO surplus of 5 to 10%. With hybrid isocyanate foams (PUR/PIR) this value is somewhat higher. Pure isocyanurate foams (PIR) with a low content of urethane groups are known for insulating purposes by reason of their good fire-retardant properhes. They are processed into blocks or slabs, there being no spe-cial requirements for foaming time and curing time and their mutual relation.
In the following, the terms "cream time", "rise time" and "tack-free time" will be used. These generally refer to the time passing from the mixing of the product until - the first starhng reaction, and until the product has assumed a vvhitish colorby reason of incipient cell fo~nation (cream time~, - the foam is fully expanded (rise time), and - the time at which a rubber glove no longer sticks to the foam surface (tack-free time).
US-A-5 294 647 (Blanpeid) discloses a method for producing CFC/water-blown, rigid PURIPIR foams which can be used as insul~ting material. The polyol component used is mainly a polyester polyol, the NCO/OH ratio being subst~nti~lly between 2:1 and 5:1. The catalyst s,vstem consists of a) a tertiary amine, and b) an organic alkali metal salt. The organic aLkali metal salt of the initiator system tempo-rarily delays urethane formation, while the tertiaIy am~ne simultaneously promotes the reaction between isocyanate and water and thus the formation of carbon dioxide, which acts as the primary foaming agent. The organic metal salt subsequently en-sures sufficient reaction heat for evaporating the CFC blowing agent and for com-plete exp~n~ion of the system before it solidifies. Component a) of the catalyst sys-tem can be selected from different types. For example, one can use bis(dimethyl-aminoethyl)ether (Thancat CDP) and 2,4,6-tris(dimethylaminomethyl)phenol (K54).
The special composition of the system permits the CFC II type chlorofluorocarbonblowing agents hitherto used to be replaced by HCFC and HCC in combination with water. The examples show that the tacl~-free ~ne is in several cases shorter ~an the rise time and that the rise time lasts extremely long, typically more than 75 sec. The high ~lk~linity can lead to hydrolysis of phosphorus-cont~inin~: fire-retardant addi-tives for example.
US-A-4 785 605 (Williarns) describes the application of stabilizing (with re-gard to reaction time~) polyester polyols for producing polyurethane or polyisocy-anate foam. The polyester polvols consist of a ~ ure of a polyester polyol with a molecular weight of ~00 to 10000 and a functionality of 2 to 6. a tertiary arnine catalyst, an organic carboxylic acid with a defined dissociation constant which does not decarboxylate, a fluorocarbon blowing agent and a certain quantity of a non-amine catalyst. To attain sufficient stability, at least as manv carboxylic acid equiv-alents are present as amine equivalents. The stable and fulthe~nore long reaction times (the rise time being more than 1 minute ) achieved with this polyester ~ ure even after long storage at elevated temperature are a consequence of salt formation between the amine and the added acid. It is therefore important to use substantially equivalent quantities of acids and ~mines Salt formation can prolong reaction ~me a little so that it can be expedient to use a little more amine catalyst and the equivalent quantity of acid. Amine catalysts can be selected at will from the class also including bis(2-dimethylaminoethyl)ether and 2,4,6-tris(methylaminomethvl)phenol.
The initiator system has also been used for other purposes, as described in l,TS-A-4 177 173 (Carr) or in an article in the Journal of Applied Polymer Science, Vol.
27, 4029-4042 (1982).
The US docl~ment describes a fast and effectively curing system of polymer-captan-polyepoxide. The system consists of a polymercaptan and at least one poly((N,N-dimethylamino)aLkyl)ether with 2. 3 or 4 terhary amino groups.
The aforementioned article contains a study of the kinetics of various catalystsand their use in conjunction with reactions of phenylisocyanate with water and phenylaniline, in particular for producing polyurea compounds. The studied catalysts also include bis(dimethylaminoethyl)ether and tris(dimethylaminomethyl)phenol.
The first step of polyurea formation, namely ~e reaction be~ween water and isocy-anate, is the step in the system that det~ ines reaction rate. The firstmenhonedamine catalyst has the highest velocity constant. There is no hint that these catalysts can be used advantageously for PUR~PIR systems.

A number of urethane catalysts are sold for example bv the firm Condea Che-mie GmbH, Germany. under the designation Thancat. Special trimerization catalysts for isocyanate foam are available for example from the firm .~nchor Chemicals un-der the designation K54.
All in all, it would be desirable to have an ultrafast reac~ing urethane foam wh~se rise time ends before lack of tackiness begins.
The aim of the invention is to provide a urethane foam which shows corre-sponding mechanical properties while avoiding the well-known problem of exces-sive expansion time and deficient tack-free time.
This aim is reached by a two-component system for producing polyurethane foams which consists of a polyol component A with at least one polyol with a func-tionality of 2 or more, water and a catalyst system comprising at least two catalysts at least one of which is able to catalyze the reaction of polyisocyanate with polyol and/or water and at least one further one of which is able to catalyze the trimeriza-tion of isocyanate groups, and a polyisocyanate component B with at least one polyisocyanate with a functionality of 2 2, the ratio between NCO groups in compo-nent B and reactive OH groups in component A being > 1.
The inventive foarn system refutes the prejudice existing on the market that ul-trafast foams cure before they fully expand and can develop their adhesive effect and that they show poor adhesiveness on melamine snrf~ces The inventive foam reachesits full volume before losing its a&esiveness, so that one attains a good bond which is stable under load between the frame structure and the ~ olL~ding masonry whenfoaming cavities and in particular assembling window and door frames.
With slow-reacnng types of foam~ the heat conductivity and capacity of the m~t~ri~l on which the foam is foamed has great importance for the result. If a large part of the reaction heat is withdrawn from the foam via the surrounding substrate, this can cause the glass temperature or necessary reaction tempelalure of the mi~Lure to "overtake" the foam temp~laLure, in particular during reaction of the isocyanate groups. which leads to stoppage of the reaction.

Melamine composites, for example chipboards with a melarnine surface, have a great heat capacity which makes it extremely difficult to keep the ~oam temperature above the glass temp~ e.
It is therefore an advantage that the inventive foam reacts and expands so quickly that it reaches melamine surfaces in a reactive and a&esive state.
The foams produced with the inventive two-component system can be charac-terized as water-blown, rigid. tough, hybrid two-component isocy~ula~e-urethane-c~l,&~ide foams. For certain purposes it can be expedient to provide a propellant component in addition to the water component, whereby one can apply propellants usual in the field. In the presence of only water, the CO2 released by the reaçtion of the water acts as the sole propellant.
The individual components and in particular the polyol part are selected so thatreaction temperature is always above glass temperature. This is extremely important since the reaction otherwise stops. This is an exactly coordinated and novel two-stage catalyst reaction whose course will be described in detail in the following.
The isocyanate component and polyol component form, after mixin~ a whitish, low-viscosity mixture cont~ining gas bubbles which foams through the reaction ofisocyanate groups with contained water so as to form CO~ until the water is con-sumed. After that the foam is a pressureless, tough material which still sticks by rea-son of the surplus isocyanate groups. Any additional blow~ng agents present, for ex-ample in the form of liquid gases or low-boiling hydrocarbons, evaporate in the course of this formation process and support foam formation.
An exactly coordinated surplus of isocyanate is of great importance so that the foam does not crosslink prematurely. For this purpose the catalyst system is de-signed so that after complete expansion of the foam the rem~ining isocyanate groups c~lsin~ a&esion trimerize into isocyallw~Le groups. After complete consumption of the isocyanate groups the foam no longer sticks.
The catalyzed formation of isocyanurate groups furthermore results in an im-provement of the flame-retardant and flame-inhibitory properties of the foam.

The combination of these two different reaction paths, urethane formation and isocyanurate forrnation~ therefore results in a number of effects which are not de-scribed and are surprising to the expert.
The inventively produced foam additionally has a good cellular structure and good strength properties as far as tensilelcompressive strength is concerned. In con-trast to pure isocyanurate foam, it has only low brittleness. It has been ascertained that the inventively produced foam has quite good strength properties which usually surpass those of canned foams found on the market. Furtherrnore, the inventive foam systems involve little bad smell during production. application and from the freshly produced foam.
The inventively used polyol component constitutes a stable mixture of polyoL
water, any optional additives and blowing agents.
These inventively achieved effects are a consequence of the combination of certain starting materials, in particular the polvols~ catalvsts~ blovving agent system and polyisocyanates. However, it must be noted that the inventive formulations are quite insensitive to deviations as far as the mixture ratio between polyol component A and isocyanate component B is concerne~ whereby the special composition of polyol component A plays a part. This is particularly important when using simple mixing systems in which the delivered material cannot alwavs be optimally mixed.Polyol component A expediently consists of a mixture of 2 or more polyols in conjunction with water, 2 or more catalysts and optionally a proportion of flame-retardant and surface-active additives. agents for influencing pore structure and rheology, and further blowing agent.
It generally holds that the polyol component should be easily liquefiable and hydrolytically stable within the temperature range important for application. The polyol component must contain polyols with fast-reacting OH ~TOUpS, i.e. primary or secondary OH groups. The functionality of the individual polyols should be 2 or more. It is essential for selection of the polyols ~at they ensure an appro~liate glass transition temperature.
It is especially suitable for inventive purposes to use difunctional block copoly-mers from propylene oxide and ethylene oxide. produced by aLkoxylation of for ex-ample ethylene ~lycol, propylene ~lycol or else water as starter molecules. These copolymers have molecular weights generally in the range of l,000 to 6 000 and OH
numbers in the ran~e of l0 to 60 mg KOHlg. Such difunctional block copolvrners are very often used as surface-active agents in d~lerge~L~ for example, but also for IC canned foarns.
Especially ~refel.ed compounds have molar weights of 2,000 to 5,000 and in particular about 4,000. They contain primary OH groups and consist of a middle se~,ment of polypropylene oxide which is termin~te~ with polyethylene oxide units.
The inventively used polyols are all liquid, low-viscosit,v compounds with relatively high equivalent weights which make the arising foam soft and elastic.
As additional or :~ltçrn~tive polyol components one can use naturallv occurring polyols, such as castor oil. Modified natural oils can likewise be advanta~eously used, for example polyols from transesterification of triglycerides not containing OH
with glycerol, ethylene glycol and other low-molecular polyols. Other examples of modified natural oils are epoxidized natural oils, as can be obtained by reaction with alcohols or polyols, for exarnple epoxidized soy oil. Finally, one can likewise use commercial diols or triols which have been obtained by propoxylation or ethoxyla-tion of starter molecules such as water, trimethylolpropane, glycerol, ethylene gly-cols, propylene glycol or the like.
Application of these special polyols permits the ~rlm~ re of relatively 8reat 4ua~1ilies of water. If hydrocarbons or sirnilar compounds are used as a propellant, they can be admixed without compatibility problems. Using pentane type propellants for example, far more water could be admixed than expected.
It is especially suitable to use the abovementioned difunctional block copoly-mers of propylene oxide, as are available for e~ample under the tr~-lem~rk~ Syn-peronic and Pluronic. The low HLB of these polyols provides good miscibility with the isocyanate component and facilitates dispersion of water. Furthermore, it stabi-lizes viscosity and acts as a solvent for other con~it lent~ of the polyol component.
A second especially suitable ~roup of polyols in polyol component A is a "hard" polyol, as sold for exarnple under the trademark Arcol. These are aromatic aminopolyols with OH numbers of 400 to 600 and a functionality of 4 to 6. In chemical terms, these are propoxylated di(hydroxyethylaminomethyl!phenols.
These are high-viscosity compounds with a syruw consistency at room tem-p~.alule. Viscosity increases with functionality. By reason of the aromatic core these compounds are self-extin~ hin~ These aromatic aminopolyols have a very steep viscosity increase below room temperature at which the aromatic aminopolyols also assume a ~lassy form. Especially good results are achieved according to the inven-tion if polyols of the firstmentioned "soft" type are combined with those of the last-mentioned "hard" type. The weight ratio of "soft" to "hard" polyols can expediently be between 6:1 and 1 2~ in paIticular between 4:1 and 1:1.
A further essential aspect of the invention is the catalyst mixture used. The special requirements for the foamin~ process and the course of curing cannot be ful-filled with catalysts used in known foam systems. One requires a catalyst systemwhich causes not only polyurethane formation but also the formation of isoc~a~urale groups. Furthermore it is essential that the catalysts used act sufficiently quickly for polyurethane formation to fulfill the requirements for rise time.
A group of catalysts meeting these requirements is amine compounds with an ether function in the 2 position from the tertiary nitrogen atom. One example of such a compound is bis(dimethylaminoethyl)ether, another is 2-dimethylaminoethyl-3-dimethylaminopropylether. Such catalysts are sold under the designation Thancat CDP or DD.
A further catalyst compound suitable for the inventive system is pentamethyl-diethylene~ mine.
Trimerization catalysts used for polyisocya~ e formation can be the usual catalysts for this reaction, such as potassium carboxylates, for example potassium acetate or octoate; Dabco TMR and Dabco TMR -2, as well as 2,4,6-tris(dimethyl-an~inomethyl)phenol, i.e. catalysts based on alkali carboxylates, q~l~tern~ry ammo-nium salts or phenol-substituted trialkylarnines. Such a catalyst is available on the market under the trade name K54.

It is particularly preferred and suitable for the inventive foam systems to com-bine a urethane catalyst of the trademark Thancat. in par~icular Thancat CDP or DD, with the trimerization catalyst K54.
The catalysts should not be too alkaline amines if the inventive two-component system contains phosphate esters as a fire-retardant. Phosphate esters are decom-posed by alkaline amines in the presence of water.
Thancat catalysts are known for fast catalysis of water or polyol with isocy-anate groups. It has turned out that they act much faster than K54 and other trimeri-zation catalysts, so that the reaction between isocyanate and water or polyol takes place faster than K54 can catalyze trimerization and curing during isocyanurate for-mation.
The two catalysts of the catalyst system and K54 can be used in equal quanti-ties of more than 0.84 wt%, preferably more than about 3.0 wt%, based on the weight of polyol and water and coordinated with the quantity of isocyanate. The content is typically altogether between 7 and 10 wt~,~o, based on polyol and water.
Polyol component A can contain not only water, which acts both as a blowing agent and as a reactive and cross~inking component, but also further blowing agents if this is necessa~y or advantageous for certain applications. One can use in this con-nection in particular low-boiling ethers, hydrocarbons and fluorocarbons as are usu-ally employed for producing polyurethane foams. It is preferred according to theinvention to use in particular dimethyl ether, propane, butane, pentane, isopentane and cyclopentane and mixtures thereof. One can generally use those liquid or lique-fiable blowing agents whose boiling point is between -40~C and 50~C.
Isocyanate component B contains at least one polyisocyanate with a function-ality of 2 or more. The polyisocyanates used can primarily be aromatic polyisocya-nates, such as MDI (methylene-4,4'-diphenyl diisocyanate) and TDI (toluene diiso-cyanate), each either in raw form or in the forrn of the pure isomers or mixtures thereof (phenylene diisocyanate, xylylene diisocyanate, triphenyl methane triisocya-nate, toluene triisocyanate, polymethylene polyphenyl polyisocyanate and NDI
(diisocyanaton~phth~lene). Further, one can use prepolymers of aromatic isocya-nates and partially prepolvmerized isocyanates, such as liquid, carbodiimide-contain-in~ MDI.
Aliphatic and alicyclic polyisocyanates can likewise be used, ~ref~l~bly also inLule with aromatic polyisocyanates. Examples are HDI ( 1,6-diisocyanatohexane) and IPDI (isophorone diisocyanate), also hydrogenated MDI and TD~. It is particu-larly preferred to use a proportion of ~liph~lic polyisocyanates of up to 50 wt% of isocyanates B.
It is alto~ether unportant that the ratio of NCO groups and OH grou~s is ~ 1 and in particular between 1.2 and 2Ø A ratio of about 1.3 to about 1.8 is preferred, one between 1.4 and about 1.6 particularly preferred. The surplus of NCO equiva-lents is essential for controlling tack-free time.
The term "NCO groups" refers to the total number of NCO groups in polyiso-cyanate component B. The term "OH groups" refers to the OH groups present in thepolyols used and moreover also includes active hydrogen as is contained for example in water and possibly in the amine catalyst and in additives and is capable of reac-tion with the NCO groups.
The isocyanate component and polyol component should be composed if pos-sible so that the components have more or less equal viscosity, which favors misci-bility. This is of some importance, particularly when mi~Lul~ iS done in simple mix-ing apparatuses such as known static mixers.
A further advantage of the inventive polyol ~lule is that viscosity is little de-pendent on temperalu-~ over a wide temperature interval of about 5~C to about 30~C, and largely equal reaction times are achieved within this temper~lure interval.
The low temperature sensitivity in relation to known cornmercial products is a special advantage since for example the room tempe~alLue in new buildings, etc.,typically extends over a wide range.
The inventive foam systems have reduced cream time and rise time compared to conventional systems, while tack-free time is suitable. Tack-free time sets in only after rise time under all circumstances, so that the foam is fully e~panded before losing its tackiness. The creamy and viscous nature of the developing product fur-~ermore leads to better a&esion to the desired site and to an optimurn foaming process without the product tending to "run out". This reduces material consumption, and one need not subsequently remove anv great amounts of (excess) foam.
The inventive two-component systems in particular permit the system to have, after mixing a cream time of 1 to 4 seconds a rise time of ~ tO 15 seconds and atack-free time of 10 seconds and more, the tack-free time always setting in only after the end of the expansion process generally about 5 seconds later.
Both polyol component A and isocyanate component B can contain usual ad-ditives as are known and find application in this field. For example the polyol mix-tures can contain relatively ~reat quantities of flame retardant typically phosphate esters or phosphonates. These can also be drawn to the foam as plasticizers. Oneshould preferably use ones which are very stable hydrolytically for example TCPP(trichloropro~yl phosphate) or Fyrol PCF (org. phosphoric ester).
The quantity of water should suffice to provide the quantity of CO2 necessary for the foaming process. On the other hand, the proportion of urea groups present in the foam should not be too great because this increases brittleness. Altogether the water content should be such that 20 to 50% of the isocyanate groups present in the system can react exhaustively with water into urea groups. The brittleness of the arising foam system can be controlled by suitable selection of "soft" polyols and by the addition of plasticizers and fire-retardant additives.
The polyol content in the polyol component is expediently such that about l0 to 50% of the isocyanate groups can react exh~1lstively into polyuredlane groups.
Simnlt~neously, the isocyanate index of the polyisocyanate component should be in the range of 120 to 200. This corresponds to a 20 to 100% surplus of isocyanate groups over the OH groups.
The blowing a~ent is provided primarily by the CO2 formed by reaction of the water. It may be desirable to add further blowing agents as well. For pressureless applications out of cartndges, one can use aliphatic or cycloaliphatic hydrocarbons with a boiling point of 25 to 50~C, for example isopentane or cyclopentane with boiling points at 28~C and 49~C.
If the polyol mixture is not fully homogeneous, the necessa~y homogeneity can be achieved by shaking the container directly before application.

The inventive two-component systems can, as mentioned, contain usual addi-tives such as surface-active compounds, thickening agents and the like.
The surface-active compounds used can be silicone compounds which ensure a stable cellular structure and result in a more elastic surface film. which is important for the foaming phase. Silicones in addition initiate bubble formation and stabilize the bubbles in the mass. As a result this can influence bubble size and elasticity.
The specific gravity of the foam can be influenced by the blowing agent. If a usual evaporable blowing agent is used it can be contained in the polyol part in a quantity of 3 to 14%, in palticular 5 to 11%, based on the polyol part.
It must furthermore be underlined that the additives necessaly for the quality of the foam can fundamentally be contained both in polyol component A and in isocy-anate component B, as required, if they do not pa~ticipate reactively in foam forma-tion.
An especially preferred polyurethane system for assembly purposes has the following composition:

Polyol component A
8 to 28 wt% difi~nctional polyol 20 to 40 wt% aromatic polyol 15 to 45 wt% flame retardant 1.5 to 10 wt% catalyst for urethane formation O to 12 wt% catalyst for trimerization 0.5 to 3.0 wt% water 0 to 12 wt% additional blowing agent (hydrocarbon') 1.5 to 3.0 wt% surface-active agent Isocyanate component B
80 to 100% polyisocyanate 20 to 0% fire-retardant additives Further preferred compositions are evident from the examples.

The inventive two-component foam systems can be produced both from pres-sureless cartridges and from pressure cans. Using pressure cans. the two components A and B can be contained in se~ te pressure cans and ~imlllt~neously discharged and mixed by an apparatus known for such purposes. For storing the two compo-nents one can also use conventionl 2C aerosol cans, however. which contain the second component in a s~ Le chamber in its interior which is opened before use by a trigger meçh~nicm o~ ted from the outside and dischalges its co~lh.,b into the ~ oul~ding pressure can.
In any case isocy~nate component B and polyol component A can be ixed and discharged with the aid of conventional eql~ipment using known techniques.
Since the inventive system can be adjusted almost without pressure. it is possi-ble to store components A and B in foil containers and apply them out of such con-tainers. This is an advantage over known pressure systems. in particular as far as product and industrial safety are concerned.

Example A number of compositions for polyol component A and polyisocyanate com-ponent B were produced. These foTmlll~tions can be stored without pressure and yield, through mixing, inventive foam systems which in each case fulfill the re-~uirements for cream time, rise time and tack-free time. All examples ,vielded very serviceable c~nnerl foams with high tensile strength suitable for application to mela-mine. For each composition the NCO surplus and NCO index are also stated~ as well as the breakdown of NCO consumption by water, polyol and tnme~7~*on.
Two-component foam systems suitable for discharge from cartridges were pro-duced from the form~ tions for polyol component A and isocyanate component B
laid down in Tables 1 and 2. All st~teme~t.s are in percent by weight, unless other-wise stated.

Table l Polyol component A
Formulation EO/PO block copolymer 1 15.9 25.3 15.9 15.9 15.9 21.2 15.9 16.2 Aromahc aminopolyol 2 25.1 25.3 25.1 25.1 25.1 33.4 25.1 25.6 Water 2.0 3.0 2.0 3.0 2.0 2.7 1.7 3.0 (OH number 6230) Cyclopentane 11.9 TMCP 50.0 40.4 48.2 48.1 49.1 33.4 35.1 47.5 Silicone SR 321 2.0 2.0 2.0 2.0 2.0 2.7 2.0 Thancat CDP 70% 3.0 3.0 1.5 0.5 0.5 4.0 3.0 1.0 K 54 2.0 2.0 5.3 5.3 5.3 2.7 5.3 2.0 OH number 262 324 262 324 262 350 243 327 Isocyanate component B
Desmodur 44V20L 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 NCO % content 31.60 31.60 31.60 31.6031.60 31.60 31.60 31.60 Cartridge Weight on filling polyol 93.3 91.1 9~.9 9~.9 93.1 90.5 89.8 93.0 Weight on filling isocyanate 96.0 g6.0 96.0 96.0 96.0 96.Q 96.0 96.0 Masstotal 189.3 187.1 188.9 188.9 189.1 186.5 185.8 189.0 NCO ~~O sulplus 6.37 4.40 6.43 4.13 6.39 3.56 7.54 4.03 NCO index 166 137 167 134 166 128 186 133 by water % 31 47 31 47 31 42 27 47 by polyol % 30 27 30 29 30 37 28 29 by tlimeri7~hon % 39 26 39 24 39 20 45 24 Sum % 100 100 100 100 100 100 100 100 EO/PO block copolymer 1 Synperonic L 121 wi~ 10% EO portio~ MW about 4400, OH number 25.5 Aromatic aminopolyol 2 Arcol 3750, OH number 530 Desmodur 44V20L raw MDI

Table 2 Polyol c~mponent A
Fonm-l~ion 211 2l2 2l3 2/4 2l5 2l6 2l7 2l8 Rape oil transe~ ified 29.0 44.0 Rape oil modified (water) 32.0 Soy oil modified (me~anol) 32.5 EO/PO block copolymer 3 37.0 37.0 EO/PO block copolymer 2 37.0 27.0 EO/PO block copolymer 1 37.0 25.0 20.0 25.0 Aromatic an~inopolyol 2 24.0 Aromatic aminopolyol 3 24.0 24.0 24.0 10.0 Water (OHnumber6230) 3 0 3.0 3.0 3 0 3 0 3.0 3.0 3.0 Plasticizer phos-phorus-cont~ining 29 5 30.5 30.5 29.5 70.0 18.5 24.5 20.0 Flameproofing agent, chlorine-co~ 6 5 8.0 Flameproofing agent~
bromine-co~2~ g, O H nuDnb~r 239 10.0 8.0 ~
Stabilizer 2.0 1.0 1.0 2.0 2 0 2.0 2.0 2.0 Bis(dimethylamino-ethyl)ether 2.0 2.0 2.0 ~.0 2.0 2.0 Pentamethyl diethylene~iamine 3 0 3.0 K 54 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 OH number ~28 331 334 329 269 271 292 289 Isocyanate component B
Desmodur 44 V 20 L 100.0 98.0 98.0 100.0 100.0 100.0 100.0 100.0 Stabilizer 1.0 1.0 Thixo~oping 1.0 1.0 NCO % content 31.60 30.97 30.97 31.60 31.60 31.60 31.60 31.60 Cartridg~
Weight on filling polyol 88.5 89.0 88.7 88.9 90.9 88.~ 88.~ 85.6 Weight on filling isocyanate 96.0 95.6 95.6 96 0 96.0 96.0 96.0 96.0 Mass total 184.5 184.7 184.3 184.9 186.9 184.2 184.5 181.6 NCO % content 4.66 4. l l 4.04 4.57 6.~3 6.76 5.98 6.51 bywater 47 47 47 47 47 47 47 47 by polyol 26 27 28 27 15 13 18 15 by trimeri7~tion 27 26 25 26 38 40 36 38 Sum in % 100 100 100 100 100 100 100 100 Table 2/contimle~ ~
Polyoi component A
Fo~mll~tion Polypropylene triol, OH number 380 ~o o Castor oil 23.0 Rape oil, modified (water) 10.5 Rape oil, modified (butanol) 34.0 EO/PO block copolymer 1 15.0 26.0 37.0 30.0 Aromatic aminopolyol 1 10.0 Aromatic aminopolyol3 11.5 Water 3.0 3.0 3.0 3.0 Plasticizer. phos-phorus-cor~ 30.0 31.5 30.0 30.0 Flameproofing agent, bromine-cont~inin~ 23.5 Stabilizer 2.0 2.0 2.0 2.0 Bis(dimeth~lamino-eth,~l~ether ~.0 ~.0 ~.0 ~.o K 54 2.5 2.5 2.5 2.5 OH number 301 277 253 297 Isocyanate component B
Desmodur 44V20L 100.0 100.0 100.0 100.0 NCO ~~O content 31.60 31.60 31.60 31.60 Cartridgc Wei~ht on filling polyol 86.8 86.4 95.2 87.5 Weight on fillin~
isocyanate 96.0 96.0 96.0 96.0 Mass total 182.8 182.4 191.2 183.5 NCO % content 5.93 6.82 6.46 5.96 by water 47 47 47 47 by polyol 19 13 13 18 by trimerization 34 40 40 35 Sum in % 100 100 100 100 Rape oil, transesterified with ethylene ~lycol (90: 10)~ OH number 180 Rape oil, epoxi~i7e~ modified with water, OH number ~48 Soy oil, epoxidized, mo~ified with methanol, OH numb~r 118 Rape oil, epoxidized. modified ~rith n-butanol, OH number 137 EO/PO block copolymer 3 ~Synperonic L81) ~ith 10% EO po~on, M~ about 2700, OH llumber 41 EO/PO block copolymer 2 (Syn~eronic L92! with ~0% EO porhon~ I~fW about340Q, OH numbe~ 3~
EOfPO '~ k ~ p(~lylll~:L i ~Synp~r~ L121) with 10% EO pOl~ IW ~out 4400, OH number 25.5 Aromatic aminopolyol I Arcol 3541, OH number 4~5 Aroma~ic 3minopolyol ~ Arcol 3750, OH number ~30 Alomatic ~i~poly~13 Arcul 375B, OH nu~lJer 5S0 All formlltations yield foams with good properties in teIms of compressive strength and a&esion to wood veneer, mei~mine~ masonry and concrete. The foams have specific gravities in the range of 30 to 50 kg/m3.
All foams according to Tables 1 and 2 showed the ri~ht order as far as rise timeand tack-free time are concerned. Foam expansion was teIm~nated after 4 to 15 sec-onds and lack of tackiness reached after 13 to 33 seconds. By reason of the ex-tremely short cream time of less than 3 seconds there was only a low tendency to run and flow off. Application was simple in each case. Especially good strength proper-ties are reached with an NCO/OH ratio of 2 1.4.

Claims (15)

Claims

1. Pressureless two-component cartridge system for producing polyurethane foams consisting of a polyol component A with at least one polyol with a functionality of 2 or more, water and a catalyst system comprising at least two catalysts at least one of which is able to catalyze the reaction of polyisocyanate with polyol and/or water, and at least one further one of which is able to catalyze the trimerisation of isocyanate groups, and a polyisocyanate component B with at least one polyisocyanate with a functionality of > 2, the ratio between NCO groups in component B and OH
groups in component A being such that 20:50% of the isocyanate groups in the system react with water to urethan groups, 10:60% of the isocyanate groups react to polyurethan groups and 20:45% of this isocyanate groups trimerize .

2. The two-component system of claim 1, characterized in that polyol component A additionally contains an organic blowing agent.

3. The two-component system of claim 2, characterized in that the organic blowing agent used is a hydrocarbon, ether, fluorocarbon and/or mixture thereof with a boiling point in the range of + 25°C to + 50°C.

4. The two-component system of claim 2 or 3, characterized in that the blowing agent consists of propane, butane, pentane, isopentane, cyclopentane, dimethyl ether or mixtures thereof.

5. The two-component system of any of the above claims, characterized in that polyisocyanate component B contains aromatic isocyantates, prepolymers from aromatic isocyanates or partially prepolymerized isocyanates.

6. The two-component system of any of the above claims, characterized in that polyol component B contains aliphatic polyisocyanates.

7. The two-component system of any of the above claims, characterized in that polyol component A contains one or more polyether polyols with a molecular weight in the range of 1000 to 6000 and an OH
number of 10 to 60.

8. The two-component system of any of the above claims, characterized in that polyol component A contains at least one aromatic aminopolyol with a functionality of 4 to 6 and an OH number of 400 to 600.

9. The two-component system of any of the above claims, characterized in that polyol component A contains naturally occurring polyols, modified natural oils or mixtures thereof.

10. The two-component system of any of the above claims, characterized in that it contains bis-(2-dimethylaminoethyl)ether, 2-dimethy-laminoethyl-3-dimethylaminopropylether, pentamethyl triethylenediamine, or mixtures thereof as the catalyst able to catalyze the reaction of polyisocy-anate with water or polyol.

11. The two-component system of any of the above claims, characterized in that it contains a potassium carboxylate, 2,4,6-tris(dimethylaminoethyl)phenol, Dabco TMR, Dabco TMR-2 or mixtures thereof as the catalyst catalyzing the trimerization of isocyanate groups.

12. The two-component system of any of the above claims, characterized in that it contains usual flameproofing agents, stabilizers, plasticizers, agents for adjusting flowability, cellular structures and viscosity and the like.

13. The two-component system of any of the above claims, characterized by an isocyanate index of the system of 120 to 200.

14. A cartridge system containing the two-component system of any of the above claims.

15. Use of the two-component system of any of claims 1 to 13 for producing canned foam, packaging foam, joint foam and casting compound.