Foaming agents containing liquid carbon dioxide

The invention relates to a method for the production of foamed plastics using liquid carbon dioxide-containing blowing agents.

The invention also relates to a method for the production of single- or multi-component polyurethane foams from pressure vessels.

The use of chlorofluorocarbons substances (CFCs) as blowing agents in the production of foamed Plastics is not for environmental reasons more desirable. When substitutes are far gaseous Substances such. As carbon dioxide suggested been. Carbon dioxide as a gaseous physical but the blowing agent has the disadvantage that it is due to its relatively low critical temperature wherein during the production of plastic foams prevailing conditions only quite difficult can dispense. Furthermore, the use of carbon dioxide to open cell according to previously known methods generally Foams with an undesirably high Water absorption capacity and an often unsatisfactory Thermal insulation. Also so far the production foamed plastics with predominantly closed Cells in the use of carbon dioxide as the sole blowing agent or as a co-blowing agent in Combination with other physical blowing agents still fraught with difficulties.

Single-component or multi-component polyurethane foams, from a pressurized container, e.g., as a Spray can be issued, are mainly for the foaming of cavities or interstices used in construction or in automotive engineering. The so-called one-component polyurethane foam is (hereinafter referred to as 1K-PUR foam) a polyol premix together with an excess of of di- and / or polyisocyanate in the presence of a Catalyst and, optionally, other auxiliaries and Additives in a pressure vessel to an isocyanate Prepolymar containing reacted. By pressing the spray valve of the pressure vessel is the prepolymer by a propellant from the can forced out, which is a spontaneous foaming the prepolymer is. reaction the remaining isocyanate groups with the humidity creates a largely closed Rigid foam.

When two-component polyurethane foam (Hereinafter referred to 2K PU foam) you need for curing the prepolymer foam another Hydroxyl-containing component, eg. B. a polyol, soft until immediately prior to foaming is added. Usually you will find this polyol in the pressure vessel in a rest of the components separated filling space and is operating the spray valve until immediately before exiting the pressure vessel of the prepolymer component added.

Most of the application of pressure vessels have used prepolymers for polyurethane foams a very high viscosity, so that the inserted Propellants have good solvent properties should order the components easily from the Pressure vessel out to be foamed. Of the Use of Fluorchlorkohlenwasseratoffen (CFCs) as a blowing agent for such applications is made from ecological Reasons no longer desirable. Lots the previously proposed substitutes show yet application disadvantages such. 3. yet unsatisfactory heat insulation or low evaporation rate.

The International patent application WO 91/12287 disclosed that liquid CO₂ with co-blowing agents, for example, water or high-boiling solvents, may establish. One can in this way a controlled pre- and post-expansion of the foam cause.

The Japanese patent application JP-A 52117957 discloses that polyethylene resins with a mixture of CO₂ and a volatile organic Blowing agent may be foamed.

The International patent application WO 91/08243 relates to the preparation open-cell polyurethane foams. Preferably, liquid CO₂ as blowing agent used that in still water or other blowing agents may contain small amounts.

Object of the invention to provide novel methods for the manufacture of foamed plastics, and also for the production of polyurethane foams, from pressurized containers, to provide that the recent Disadvantages of the prior art overcome, wherein suitable for this method new blowing agent compositions user wide should.

Surprisingly, it has now been found that compositions which in addition to at least one other liquid component in liquid carbon dioxide included form, as blowing agent compositions in processes for the production of foamed plastics suitable. Treibmittelzusammansetzungen which contain liquefied carbon dioxide, are also suitable for the production of polyurethane foams from pressure vessels.

In addition to the liquid CO₂ is at least one other liquid or pressure-liquefied component contain. This further liquid component or the other liquid components preferably provide the balance to 100 wt .-% of blowing agent composition . In the other, or the liquid components can it beispieisweise liquid or pressure-liquefied physical blowing agents and / or to liquid flame retardants, for example, from Group of phosphate esters or phosphonic, act. Moreover, in addition also known Additives and auxiliaries, such as stabilizers or be plasticizers.

The invention provides a method for the production of foamed plastics with the aid of of blowing agents, which comprises reacting a liquid blowing agent composition uses which 5 to 50 wt .-%, particularly 10 to 50 wt .-%, especially 10 to 20 wt .-%, liquefied Carbon dioxide.

Liquefied carbon dioxide according to the invention can search for all known processes for gas liquefaction, preferably by pressure liquefaction are obtained.

Carbon dioxide at room temperature under normal pressure (1,01325 • 10⁵Pa), a colorless gas, which is by applying a pressure of 56.5 atm (=5,72486 • 10⁶Pa) at 20 ° C to a colorless, slightly druckverflüssigen moving fluid can process to pressure liquefaction of carbon dioxide are generally known.

An embodiment of the present invention refers to the production of foamed Plastics, for example by casting or extrusion processes. Another embodiment of the Invention, which will be explained later, relates specifically to the Formulation of one- and two-component polyurethane foams from pressure vessels (PUR = polyurethane). In the following, first the former Embodiment described in greater detail.

As further liquid components besides the pressure-liquefied carbon dioxide are useful in preparing foamed plastics all conventional liquid physical blowing agents, namely volatile organic Compounds such as ethers, eg., Diethyl ether, ketones such as acetone, hydrocarbons such as pentane, hexane, Heptane, gasoline mixtures, halogen-containing hydrocarbons or halogen-containing ethers verwandbar. Also under pressure liquefied gases such. As propane or butane, in addition to the liquefied carbon dioxide be used. A further possible liquid Blowing agent component of water in question.

Preferably employed for producing foamed Plastics, a blowing agent composition, a, which 10 to 20 parts by weight liquefied carbon dioxide and 30 to 90 parts by weight of at least one liquid liquefied or pressurized physical blowing agent from the group of alcohols having 1 to 5 carbon atoms, aliphatic hydrocarbons having 2 to 12 carbon atoms, cyclic hydrocarbons of 3 to 12 carbon atoms, halogen-containing hydrocarbons having 1 to 5 carbon atoms or halogen-containing containing ethers with a total of 2 to 6 carbon atoms or consists of a. Alcohols are particularly Ethanol and isopropanol are preferred. Examples for aliphalische hydrocarbons are pentane, hexane, Heptane and Benzinfraktionsn, especially Mineral spirits having a boiling point in the range 15 to 80 ° C. Furthermore can also as a liquid blowing agent component the niedersiedene fractions such. B. used propane and / or butane, liquefied under pressure, will. Examples of cyclic hydrocarbons are cycloaliphatic hydrocarbons, preferably Cyclopropane, cyclopentane and cyclohexane. Among halogen-containing hydrocarbons, hydrogen enthaltende Fluorkohlenwasserstoffe Roger that. Examples for hydrofluorocarbons are pentafluoroethane (R125), 1,1,1,2-Tetrafluorethan (R134a), 1,1,1-Trifluorethan (R143a), 1,1,2-Trifluorethan (R143), 1,1-Difluorethan (R152a), 1,1,1,3,3-Pentafluorpropan (R245fa) octafluoropropane (R218), or 1,1,1,3,3-pentafluorobutane (R365mfc). Halogen-containing Ethem be hydrogen-containing chlorofluorocarbons or fluoroether such. B. difluoromethoxy-2,2,2-trifluoroethane understood (E245).

Preferably, a blowing agent composition used comprising 10 to 20 parts by weight liquefied Carbon dioxide and 30 to 90 parts by weight of at least a halogen-containing hydrocarbon or an aliphatic hydrocarbon or a halogen-containing Ether containing or referred to from the Mixture is.

Is particularly preferred in the invention The method used a blowing agent composition, comprising 10 to 20 parts by weight liquefied Carbon dioxide and 30 to 90 parts by weight of 1,1-difluoroethane (R152a) contains or it be-is. Also particularly preferred is a blowing agent composition containing 10 to 20 Parts by weight liquefied carbon dioxide, 50 to 70 parts by weight 1,1-difluoroethane (R152a) and from 20 to 35 parts by weight Ethanol contains or consists of a mixture inventive anthaltenden Among the halogenated ethers Compositions are those Blowing agent compositions particularly preferably, comprising 10 to 20 parts by weight liquefied carbon dioxide and 80 to 90 parts by weight Difluormathoxy-2,2,2-trifluoroethane (E245) containing or consisting of Mixtures exist. Of the aliphatic hydrocarbons is particularly preferably n-pentane. Preferably should an aliphatic hydrocarbons containing composition of the invention 10 to 20 parts by weight liquefied carbon dioxide and 80 to 90 parts by weight of n-pentane, and optionally additionally contain from 1 to 3 parts by weight of water or consist of such a mixture.

In all of these propellant mixtures can be prepared by Use of the liquid CO₂ The amount of the other Treibmittein be reduced. CO₂ is physiologically safe and environmentally friendly.

Advantageously, the present invention is A process for the production of foamed plastics as Casting or extrusion process carried out. In the extrusion process used for production of foamed plastics suitable mixtures directly to the foamed sheets, films, moldings, Profiles or particles extruded. particular preference According to the invention foamed thermoplastic Plastics, in particular polyethylene, polypropylene or polystyrene foams produced. According to the process is carried out in such, that foamed into a melt for producing the Plastics suitable starting products the blowing agent composition of liquefied Carbon dioxide and a further liquid physical Admixing a blowing agent and the polymerization of the Output products for the manufactured foamed Plastic optionally while maintaining a weak positive or negative pressure during the foaming is carried out. For the novel The method can thereby known per se Processing plants, for. Example, extruder equipment used will. It is particularly surprising is, that it is possible with the inventive method is carbon dioxide in liquefied state even at elevated Temperature in the extruder for the purpose of Foaming thermoplastic polymer melts bring. In contrast to the previously known The method of the prior art is thus a problem Dosage of carbon dioxide possible. After the process of the invention succeeds under order Use of carbon dioxide predominantly closed Foams of very uniform prepare fine-cell structure. drawing addition is obtained, the process of the invention foamed plastics by a high thermal insulation capacity out.

The process for producing erfindüngsgemäße foamed plastics may performed be, that a pre-assembled in a pressure vessel Blowing agent composition used, which was prepared by reacting in a pressure vessel the liquid or liquefied pressurized physical Propellant in the desired Gswichtsteilen submit and liquefied under pressure in a known per se Carbon dioxide pushes in the desired amount. It can after the procedure arfindungsgemäßen but also possible to proceed so that to be used on the Blowing agent composition until immediately before Autschäurnvorgang in the foamed Polymers or polymerizable components manufactures. Here, in the appropriate amounts in a pressure vessel outside the actual extruder system liquefied carbon dioxide in the other liquid Blowing agent component under a pressure, under which carbon dioxide is in the liquid state is present, initiated, where the components largely mix. The homogeneous mixture obtained from liquefied carbon dioxide and liquid blowing agent component is then an inlet for liquid Propellant soldered into the extruder system.

The inventive method is suitable for making open cell as closed Rigid or flexible foams. Particularly suitable is the process for the production of foamed Polyurethane plastics. For this purpose, a known PUR processing plants, for. Example, high-pressure or low-pressure mixing systems, with which the known prior art static Mixers are equipped, can be used.

In a variant for producing foamed PUR plastics can Propellant next pressure-liquefied carbon dioxide and one or more liquid and / or under pressure liquefied physical blowing agents, further liquid additive, eg. as flame retardants, as a additional component. Conventional flame retardants are z. B. phosphate esters or phosphonates. Especially well suited are appropriate phosphate ester or phosphonate, the three lower alkyl or three, by one or more halogen atoms substituted having lower alkyl. lower is preferably C₁- To C₄-Groups. Suitable sind z. B. Tris-chlorisopropylphosphat, Trichlorisopropylphosphat, Tris-chlorethylphosphat, Trichlorethylphosphat, Trichlorpropylphosphat, Tris-chlorpropylphosphat, Triethylphosphat, Dimethylethylphosphat. Tris-dichlorisopropylphosphat or dimethyl methyl.

If the novel process for producing used foamed polyurethane plastics, so can Here all the usual foam raw materials such., aliphatic, cycloaliphatic or aromatic di- or Polyisocyanates. examples for Foam raw materials include. B. 2,4- and 2,8-Toluylandiisocyanat, Diphenylmethandiisocyanat, Polymethylenpolyphenylisocyanat and mixtures thereof. It can also Carbodilmidgruppen, urethane groups, allophanate groups, Isocyanuratgruppen, Hamstoffgruppen Polyisocyanates containing biuret groups or contained, the one as' modified polyisocyanates "or" isocyanate prepolymers " are referred to, are used. In the preparation of be of foamed polyurethane plastics Polyisocyanates usually reacted with compounds isocyanate groups, the at least two containing reactive hydrogen atoms, for example, Compounds containing hydroxyl groups on polyester, polyether and amine base, and Amino and / or carboxyl and / or having Thlolgruppen Compounds. Furthermore, all can in Production of foamed polyurethane plastics used Catalysts, such as. For example, tertiary amines and / or organometallic compounds such as Tin salts of carboxylic acids are used.

If the novel process for producing from polystyrene or polyethylene foams used also can run all known Foam raw materials are used.

In manner known per se can additionally the polymer and / or polymerizable components all per se known additives or auxiliaries, For example Nuklisierungsmittel, Porenregiersubstanzen, Flame retardants, antistatic agents, stabilizers, Plasticizers, crosslinking agents, fillers or colorants be attached.

Another embodiment of the invention relates to the production of one- or Mehrkomponenlen PUR foams of pressure vessels and is hereinafter Also described here is used a blowing agent composition, 5 to 50 wt .-% liquefied WHAT₂ contains

Under blowing agent composition is in the Pressure vessel entrapped liquid fraction of the Treibmittetzusammensetzung, including those resulting in the pressure vessel contained understood gas phase.

The propellant composition comprises, in this Variant in addition to the liquid CO₂ at least one more liquid component. As further liquid component For example, a liquid or liquefied under pressure physical blowing agent may be contained. Halogenated blowing agents are suitable, halogen-free Propellants are often environmentally acceptable and preferable. According to one particularly advantageous variant, liquid CO₂ as the only blowing agent, the liquid further component is a liquid Flame retardants from the group of esters of phosphoric acid or of esters of phosphorous acid formed.

As further liquid components besides the pressure-liquefied carbon dioxide, all conventional liquid physical blowing agents, namely volatile organic compounds such as ether, acetone, hydrocarbons such as pentane, heptane, hexane, gasoline mixtures, halogen-containing hydrocarbons or halogen-containing Ether possible. Also liquefied under pressure Gases, such as. For example, propane or butane, in addition to the liquefied carbon dioxide are used.

Preferably contain Blowing agent compositions more than 5% by weight, in particular 5 to 50, z. B. 5 or 10 to 30% by weight, liquefied carbon dioxide.

Preferred Traibmittelzusammensetzungen, comprising 10 to 50 parts by weight liquefied carbon dioxide and 30 to 90 parts by weight of at least one liquid or liquefied pressurized propellant from the group of ethers having 2 to 4 carbon atoms, the ketones having 3 to 5 carbon atoms, the aliphatic hydrocarbons having 2 to 12 carbon atoms, the halogen-containing hydrocarbons, having 1 to 5 carbon atoms or the halogen-containing containing ethers with a total of 2 to 6 carbon atoms or consist of such a mixture. Examples of aliphatic hydrocarbons are pentane, Hexane, heptane and petroleum fractions, in particular Mineral spirits having a boiling point in the range 15 to 80 ° C. Preferably, the low boiling fractions, such as. for example, propane and / or butane, in pressure-liquefied Form used. Examples of cyclic hydrocarbons are cyclopropane, cyclopentane, and Cyclohexane. Among halogenated hydrocarbons be understood containing fluorocarbons hydrogen. Examples of fluorocarbons are Pentafluorethan (R125), 1,1,1,2-Tetrafluorethan (R134a), 1,1,1-Trifluorethan (R143a), 1,1,2-Trifluorethan (R143), 1,1-Difluorethan (R152a), 1,1,1,3,3-Pentafluorpropan (R245fa), Octafluorpropan (R21B) or 1,1,1,3,3-pentafluorobutane (RS65mfc). Among halogenated ethers are containing hydrogen Chlorofluorocarbons or fluoroether such. B. difluoromethoxy-2,2,2-trifluoroethane understood (E245). Examples for possible ethers are dimethyl ether or diethyl ether. Of the ketones particular Acelon is preferred.

The blowing agent compositions can be trei of halogenated blowing agents and only from liquefied carbon dioxide as the sole Blowing agent component composed. Preference is given to mixtures, the liquefied carbon dioxide in a Amount of 20 to 30 parts by weight, and butane, or a Propane / butane mixture in an amount of 50 to 60 Parts by weight and / or acetone in an amount of 5 to 15 parts by weight or consist thereof. As propane / butane mixture, a usual se Mixture, such as a mixture with a Vapor pressure of about 3.7 bar (abs.) Are used.

Also preferred are blowing agent compositions, comprising 10 to 50 parts by weight liquefied carbon dioxide and 10 to 90 parts by weight a halogen-containing hydrocarbon or a halogen-containing ether, containing or consist. Particularly preferred are blowing agent compositions, comprising 10 to 30 parts by weight liquefied carbon dioxide and of the halogen-containing Hydrocarbons from 10 to 90 parts by weight 1,1-Difluorethan (R152a) contain or consist of. Among containing the halogen-containing ethers Such compositions are blowing agent compositions particularly preferably, 15 to which 40 parts by weight liquefied carbon dioxide and 10 to 20 parts by weight difluoromethoxy-2,2,2-trifluoroethane (E245) contain or consist of.

In another particularly preferred variant can the blowing agent addition pressure-liquefied carbon dioxide as a liquid component commonly used as a flame retardant phosphate ester or phosphonates. are particularly well suited Phosphate or phosphonate, the three C1 C4 alkyl groups, optionally but one or more halogen atoms are substituted, such as, for. example trischloroisopropyl, Trischloroethyl, trichloroethyl, Trichloropropyl, tris, Triethylphosphat, Dimethylethylphosphat, Tris-dichlorisopropylphosphat or dimethyl methyl phosphonate, contain. Appropriately, the concentrations thereby liquified at 10 to 50 parts by weight Carbon dioxide and 80 to 100 parts by weight Phosphate esters or phosphonate is preferable to use Tris one. These particularly preferred Blowing agent compositions are free of other blowing agents than CO₂ and therefore especially environmentally friendly.

The blowing agent compositions suitable for production of all known PUR foams from pressure vessels, in particular for foaming t K and 2K PU foams. Also for the production of multi-component polyurethane foams, where the foaming having more than one reactive component separately in a Pressure vessels are filled, can eingeselzt blowing agent compositions will. Also for the production of so-called 1.5 PUR foams, in which, unlike the 2C foams the prepolymer shortly before application insufficient to implement the isocyanate Amount of a polyol is added, can Treibmittetzusammensetzungen be used.

Be very advantageous prove the Blowing agent compositions for the preparation of of 1K or 2K PUR foams.

In the to be foamed 1K PU foam mixture possibility to known per se a Polyol, a polyisocyanate, a catalyst and, if appropriate, as auxiliary a flame retardant, as further constituents besides contain the blowing agent composition.

The polyol may include. For example, glycerol, glycols or polyether polyols, as the addition products of propylene oxide or ethylene oxide with polyhydric alcohols, Water or ethylene diamine were obtained, or polyester polyols, as the polycondensation of polyols with dicarboxylic acids or their anhydrides were obtained, or mixtures thereof in the 1K-PUR foam mixture may be contained. A typical Polyol may, for. Example, a mixture of a brominated polyether polyol (for example diol or triol) and having a hydroxyl number of 200 to 350 a polyether polyol (eg. as a diol) having a hydroxyl be of 110th Also suitable are modified Vegetable oils with an OH number in the range of 100 to 300, z., Castor oil, possible.

Suitable polyisocyanate components can, for example, Diphenylmethane-4,4'-diisocyanate, diisocyanatotoluene, 1,5-Diisocyanato-naphthalin, Triisocyanato-triphenylmethan, 1,6-diisocyanatohexane, preferably Diphenylmethane-4,4'-diisocyanate, or mixtures thereof, be used.

Typical catalysts in 1K-PUR foam mixtures, the method in accordance with the invention with a Blowing agent composition can be foamed, are organic amines, Aminoalkohole oder Aminoether, z. B. 2-Dimethylaminoethyl-3-Dimethylaminopropylether, Diethanolamin, Dimethylcyclohexylamin, 2-Dimethylaminoethylether, or morpholine compounds such as z. B. 2,2-dimorpholinodiethylether, N,N-Dimethylaminoethylmorpholin, N-Methylmorpholin. Preferably, the morpholine are, in particular 2,2-dimorpholinodiethylether.

As usual flame retardants can trischloroisopropyl, Trichlorisopropylphosphat, trischloroethyl, Trichloroethyl, tris, Trichlorpropylphosphat, Dimelhylethylphosphat, Trisdichlorisopropylphosphat, Dimethylmethylphosphonat, Dimethylenethylphosphat preferably Tris be used.

Stabilizers z. B. are copolymers of siloxane suitable.

One to be foamed 1K-PUR foam mixture comprises, based on the mixture as a foam 100 wt .-%, for example 20 to 30 wt .-% of a polyol component, 40 to 60 wt .-% of a polyisocyanate component, 0.1 to 3 wt .-% of catalyst, optionally 10 to 15 wt .-% of a flame retardant, optionally 1 to 2 wt .-% foam stabilizer in addition to 15 to 35 wt .-% of the blowing agent composition. A typical one-component polyurethane foam mixture, which advantageously using the foaming blowing agent composition leaves, thus for example from about 22.5 wt .-% of Polyol, for. Example, of a mixture of brominated polyether polyol with a hydroxyl number of 200 to 350 and a polyether polyol having a hydroxyl of 110 in the ratio 1: 1, about 42.5 Wt .-% of a polyisocyanate, z. B. diphenylmethane-4,4'-diisocyanate, about 0.5 wt .-% of a catalyst substance wie z. B. 2,2-Dimorpholinodiethylether, about 1.5 wt .-% silicone surfactant, about 13 wt .-% a flame retardant such. as tris, and a proportion of about 20 wt .-% of the propellant composition. Accordingly, such 1K PU foam mixture a Einkomponentenschaumstoff with a uniform fine cellular structure and low density, z. B. having a bulk density of about 23 to 25 kg / m³, produced will.

differ from the one-component foams the 1.5- and 2-component PU foams by that the time required for curing of the foam Polyol component separated in the pressure vessel of the Prepolymer is maintained and only added immediately before foaming the prepolymer becomes. The second component of this context are all already mentioned polyol components in question. to faster cure, the second component Moreover, a conventional catalyst, for example, the above-mentioned amine or morpholine compounds or organometallic compounds, wie z. B. Zinndioctoat, Kobaltnaphtenat, Dibutylzinndilaurat or iron acetonyl contain.

The with the Treibmitlelzusammensetzungen produced 1K or multi-component polyurethane foams exhibit very good thermal insulation capacity and are therefore well suited for insulating purposes, z. B. in the building or living area, suitable. Also for the production of polyurethane-based Sprühldebern the blowing agent compositions suitable.

Furthermore, the invention comprises a method for Preparation of a 1K or 2K-PUR foam, with which one of a pressure vessel comprising a polyurethane foam mixture of a polyol component, a Isocyanate prepolymer contained, a catalyst and optionally further conventional excipients and one of the above-described Tresbmittelzusammensetzungen contains, a PUR foam by venting the pressure prevailing in the pressure vessel Overpressure generated at atmospheric pressure via a valve. Appropriate pressure vessels and for foaming suitable valves are generally known

The invention 1K or multicomponent polyurethane foam mixtures relates to produce a PUR foam from pressure vessels, which one of the blowing agent compositions described above contain.

Another object of the invention is a method for the preparation of a blowing agent composition for the production of polyurethane foams from Pressure vessels, in which liquefied carbon dioxide employing as a blowing agent component. In the erfindungsgemäßan Process in a pressure vessel the liquid or liquefied pressurized physical Blowing agent component in the desired parts by weight submitted and liquefied in a known per se, normally liquefied under pressure, carbon dioxide pressed into the desired amount. In a Pressure tank (aerosol can), which already the prepolymer and optionally all other components contains, then this can arfindungsgamäßen produced in the blowing agent composition desired amount to be injected. The amount of Carbon dioxide and usually only by the for aerosol cans erlaubtan Pressure regulated (10 to 18 bar).

According to the invention it is now possible, PUR foam blends containing pressure vessel produce, which per 1 kg of tin about 20 to 30 g of carbon dioxide may contain. After previously used Processes in which carbon dioxide is always in a gaseous Form was used, it was until now only possible per 1 kg of tin introduce only about 3 to 5 grams of carbon dioxide. Advantageously, it is according to the invention now possible in the manufac ng of PUR foams from pressurized containers the quantity of flammable physical liquid or liquefied under pressure propellants further reduce. From a cost perspective is a reduction of the usual liquid or pressure-liquefied physical blowing agents extremely advantageous with the present invention Blowing agent composition produced 1K or Multicomponent polyurethane foams has a primarily closed very uniform fine cell structure and a very high thermal insulation capacity. Accordingly, polyurethane foams are, which with an inventive Blowing agent composition were prepared, particularly good for insulation purposes in the construction and housing sector.

The following examples illustrate the invention closer erläutem without, however, its scope limit.

Examples

1.

Preparation of a polystyrene foam

a)

Liquefied carbon dioxide / R152a as blowing agent

:

There was added 200 kg of polystyrene (melt index 3.0 to 110) with 2 kg of talc as Nuklisierungsmittel and this mixture in a conventional extruder system metered and melted. In the Melting zone of the extruder were via an injection nozzle in the polystyrene melt about 6 wt .-% of Blowing agent, based polystyrene, metered. The Blowing agent composition containing 14 parts by weight liquefied carbon dioxide and 86 parts by weight R152a. The vapor pressure of the propellant composition was about 14 bar at 20 °C.

In the mixing zone the polystyrene melt was with the blowing agent composition homogeneously mixed, and then the resulting mixture is extruded through a nozzle. A closed-foam of uniform, feinzeiliger structure.

There were both polystyrene foam sheets as even polystyrene foam panels according to the invention produced. A polystyrene foam sheet produced by this invention had a density of about 35 kg / m³ a polystyrene foam sheet produced by this invention a density of about 33 kg / m³.

b)

Liquefied Carbon Dioxide / R152a / ethanol Propellant:

As described in Example 1 a) was dissolved in a polystyrene melt about 8.5 wt .-% of the blowing agent, based on polystyrene, metered. The Trebmittelzusammensetzung contained 14 parts by weight liquefied Carbon dioxide, 57 parts by weight of R152a and 29 parts by weight of ethanol. The vapor pressure of these Propellant compositions was approximately 15 bar at 20 ° C.

A polystyrene foam sheet produced by this invention had a density of about 36 kg / m³. a polystyrene foam sheet produced by this invention a density of about 34 kg / m³.

2. <u>Preparation of a polyethylene foam</u>

(Not of the invention)

a)

Liquefied Carbon Dioxide / R152a / R141b as Propellant:

200 g of polyethylene (melt index from 3.5 to 150) were under identical conditions as in Example 1 described for polystyrene foam, extruded. There are approximately 6 wt .-% of a blowing agent mixture, based on polyethylene, metered. A blowing agent composition from 14 parts by weight of liquefied carbon dioxide, 50 parts by weight of R152a and 36 parts by weight R141b was used. It was a fine-celled Polyethylene foam with low get shrinkage. The produced Polyethylene foam tube had a density of about 40 kg / m³ on.

3. <u>Preparation of a PUR foam</u>

To produce the polyurethane foam was used as one of the starting components a polyol, consisting of 40 parts by weight of an ethylene / -propylene polyether (OH number 480), 60 parts by weight a sorbitol / glycerol / propylene oxide polyether (OH number 490), 1 part by weight of foam stabilizer (type DC193 from Dow Coming Corporation) and 1.5 parts by weight Dimethylcyclohylamin eingesetzl. diisocyanate was as isocyanate in a 10 wt .-% erhähten stoichiometric amount used. The PUR foams were produced in a Low-pressure system with a discharge capacity of about 8 kg / min, with a dosage of 3 components is possible. produced. one served as the mixing unit static mixer.

a)

Liquefied Carbon Dioxide / R141b / Water as Propellant:

(Not accordance with the invention)

A blowing agent composition in an amount of 30 parts by weight was used. The blowing agent composition liquefied consisted of 13.9 parts by weight Carbon dioxide, 85.1 parts by weight of R141b and additionally 1 part by weight of water. With this Blowing agent composition was a rigid polyurethane foam with a fine cellular Structure and a density of about 24 kg / m³ produced.

b)

Liquefied Carbon Dioxide / n-pentane / water as Propellant:

Furthermore, a polyurethane foam with 18 was By weight of a Treibmittetzusammensetzung produced. This blowing agent composition consisted of 13.9 parts by weight liquefied carbon dioxide and 85.1 parts by weight n-pentane, and additional 1 part by weight of water. With this composition, a propellant Rigid polyurethane foam with a fine cellular structure and a density of about 25.4 kg / m³ receive.

c)

Liquefied Carbon Dioxide / E245 as Blowing Agent

Furthermore, a polyurethane foam with 35 was Parts by weight of a blowing agent composition produced. This blowing agent composition consisted of 14 parts by weight liquefied carbon dioxide and 85 parts by weight E245. This blowing agent composition was a rigid polyurethane foam having a fine cell Structure and a density of about 33.5 kg / m³ receive.

4.

<u>Liquefied carbon dioxide / propane / butane / acetone as blowing agents for 1K-PUR foams:</u>

<sl><li>a) 247 g of a polyol premix consisting of<sl><li>73 g Polyetherpolyol (Diol), bromiert, Hydroxidzahl that. 240,</li><li>73 g Polyetherpolyol (Diol), Hydroxidzahl ca. 110</li><li>89 g tris,</li><li>5 g Silikonschaumstabilisator,</li><li>7 g Dimorpholindiethylether,</li></sl>were in an aerosol can of aluminum with a Volume of 1000 cm³ filled. There were 356 g Diphenylmethane-4,4'-diisocyanate were added and the aerosol can with a foam aerosol valve closed. A blowing agent composition according to the invention was prepared by mixing in a Pressure vessel 62 g of pressure-liquefied propane / butane submitted and 10 g of acetone and 28 g of pressure-liquefied trains give carbon dioxide with mixing has been. 99 g of this foaming agent composition according to the invention were then a conventional aerosol dispenser in the foam components containing aerosol can injected. The aerosol can was shaken shortly and for about 24 hours to form the prepolymer ditched. After this time, the one-component polyurethane foam mixture was ready for use. The 1K polyurethane foam mixture was purified the blowing agent composition according to the invention expelled from the aerosol can. This gave a polyurethane foam with a density of about 23 kg / m³ of uniform, fine-celled Structure. The shrinkage of the PUR foam after storage for 7 days at a humidity of about 90% was about 5 percent in the length agent.</li><li>b) As described under a), was a polyol mixture and a polyisocyanate in an aerosol can same volume filled. As inventive Blowing agent composition was a Composition of 50 g propane / butane, 7.5 g Of acetone and 20 g of liquefied carbon dioxide employed. The preparation of the blowing agent composition and the filling into the aerosol can was carried out, as described under a). The blowing agent composition of the invention with this produced PUR Schaumsloff showed a bulk density of about 25 kg / m³.</li></sl>

5. <u>Liquefied carbon dioxide / propane / butane / R141b as blowing agents for 1K-PUR foams:</u>

(Not according to the invention)

A polyol blend and a polyisocyanate was, as described in Example 4, in an aerosol can with a volume of 1000 cm³ filled. As Blowing agent composition was a Composition of 62 g propane / butane, 10 g R141b and 28 g of liquefied carbon dioxide employed. The production of the propellant composition and their bottling was performed in the aerosol can, as in Example 4 described.

The with this blowing agent composition showed PUR foam produced a bulk density of about 25 kg / m³.

6. <u>Liquefied Carbon Dioxide / trichloropropyl / R141b as blowing agents for 1K-PUR foams:</u>

(Not of the invention)

214 g of a polyol mixture and 356 g of polyisocyanate were prepared as described in Example 4, in a Aerosol can with a volume of 1.000 cm³ filled. An inventive composition was prepared by mixing 100 g of tris and charged with 10 g R141b in a pressure vessel, and 28 g added pressure-liquefied carbon dioxide with mixing has been. 99 g of this blowing agent composition were prepared as described in Example 4, in the aerosol can bottled.