Foaming agents containing liquid carbon dioxide

IS 2 117 451 T5

DESCRIPTION

Blowing agents containing liquid carbon dioxide.

The present invention relates to a process for manufacturing foamed synthetic materials using blowing agents containing liquid carbon dioxide.

The invention also relates to a process for the manufacture of one or more component polyurethane foams from pressure vessels.

The use of fluorochlorohydrocarbons as blowing agents in the manufacture of foamed synthetic materials is no longer desirable for ecological reasons. Substitute materials have hitherto also been proposed gaseous substances, such as, for example, carbon dioxide. However, carbon dioxide in the form of a gaseous physical blowing agent has the disadvantage that it can only be dosed with great difficulty, because of its relatively low critical temperature under the conditions prevailing during the production of plastic foams. Furthermore, the use of carbon dioxide according to hitherto known processes leads, in most cases, to open-celled foamed materials, which have a water absorption capacity so high that it is not desired and a thermal insulation that with frequency is often still unsatisfactory. On the other hand, difficulties still remain in the manufacture of predominantly closed cell foamed synthetic materials when carbon dioxide is used as the sole blowing agent or as a co-blowing agent in combination with other physical blowing agents.

Polyurethane foams of one or more components that are supplied from a pressure tank, for example from a spray can, are mainly used to fill voids or interlayer spaces with foam in construction or in the manufacture of automobiles. In so-called one-component polyurethane foam (hereinafter referred to as "1K-PUR foam"), a polyol premix is ​​reacted together with an excess of di- and / or polyisocyanate in the presence of a catalyst and optionally other adjuvants and additives, in a pressure vessel to give a prepolymer containing isocyanate groups. By actuating the spray valve of the pressure vessel, the prepolymer is squeezed out of the container by a blowing agent, thereby causing spontaneous foaming of the prepolymer. By reaction of the isocyanate groups still existing with the humidity of the air, a hard foam is originated, largely with closed cells.

In the case of a two-component polyurethane foam (hereinafter referred to as "2K-PUR foam"), another component bearing hydroxy groups, for example a polyol, is needed to harden the prepolymer foam, which only add immediately before foaming. Commonly, this polyol is in the pressure vessel within a chamber separate from the other components and is added to the prepolymer component by actuating the spray valve immediately prior to exit from the pressure vessel.

Most of the prepolymers used for application from pressure vessels for PUR foams have a very high viscosity, so the blowing agents used must have good solvent properties, in order to be able to foam the components without problems when leaving the pressure vessel. . The use of fluorochlorohydrocarbons as blowing agents for these types of applications is no longer desirable, for ecological reasons. Many of the substitute materials proposed up to now still have technical application drawbacks, such as, for example, still unsatisfactory thermal insulation or too low an evaporation rate.

International patent application WO 91/12287 discloses that liquid CO2 can be used with co-blowing agents, for example water or higher boiling solvents. In this way a controlled pre- and post-expansion of the foam can be effected.

Japanese patent application JP-A 52 117 957 discloses that polyethylene resins can be foamed with a mixture of CO2 and an easily volatile organic blowing agent.

International patent application WO 91/08243 refers to the production of open-pore polyurethane foams. Preferably, liquid CO2 is used as the blowing agent, which may also contain water or other blowing agents in small amounts.

The mission of the invention was therefore to make available new processes for manufacturing foamed synthetic materials and also for creating PUR foams from pressure vessels, which would overcome the disadvantages that hitherto had the known state of the art, having to use new compositions of suitable blowing agents for these procedures.

Surprisingly, it has now been found that compositions which, together with at least one other liquid component, contain carbon dioxide in liquid form, are suitable as blowing agent compositions in processes for the production of foamed synthetic materials. Blowing agent compositions containing liquefied carbon dioxide are also suitable for creating PUR foams from pressure vessels.

IS 2 117 451 T5

In addition to the liquid CO2, at least one other liquid or pressure-liquefied component is also contained. This additional liquid component or the other liquid components preferably represent the balance up to 100% by weight of the blowing agent composition. The additional liquid component (s) may be, for example, liquid or pressure-liquefied physical blowing agents and / or liquid flame retardants, for example from the group of phosphoric acid esters or phosphonic acid esters. . In addition, known additives and adjuvants, such as stabilizers or plasticizers, may also additionally be present.

Object of the invention is a process for producing foamed synthetic materials with the aid of blowing agents, in which a liquid blowing agent composition is used containing 5 to 50% by weight, in particular 10 to 50% by weight and very in particular 10 to 20% by weight of liquefied carbon dioxide.

In the sense of the invention, the liquefied carbon dioxide can be obtained by all processes known per se for the liquefaction of gases, preferably by pressure liquefaction.

Carbon dioxide is a colorless gas at room temperature and normal pressure (1.01325 · 10⁵ Pa) that, applying a pressure of 56.5 atm (= 5.72486 · 10⁶ Pa) at 20 ° C, it can be liquefied under pressure to give a colorless, easily movable liquid. Procedures for the pressure liquefaction of carbon dioxide are generally known.

One embodiment of the present invention relates to the production of foamed plastics, for example by casting or extrusion. Another embodiment of the invention, which is explained below, relates especially to the production of one or two-component polyurethane foams from pressure vessels (PUR = polyurethane). In the following, the first-mentioned embodiment is explained in more detail.

As additional liquid components, in addition to carbon dioxide liquefied under pressure, all customary liquid physical blowing agents can be used in the production of foamed plastics, namely easily volatile organic compounds, such as ethers, for example diethyl ether, ketones. such as acetone, hydrocarbons such as pentane, hexane, heptane, gasoline blends, halogenated hydrocarbons, or halogenated ethers. In addition to the liquefied carbon dioxide, it is also possible to use gases liquefied under pressure, such as, for example, propane or butane. Furthermore, water also comes into consideration as a liquid component of a blowing agent.

Preferably, a blowing agent composition containing 10 to 20 parts by weight of liquefied carbon dioxide and 30 to 90 parts by weight of at least one liquid or liquefied physical blowing agent is preferably used for the production of foamed plastics. group pressure of alcohols with 1 to 5 carbon atoms, aliphatic hydrocarbons with 2 to 12 carbon atoms, cyclic hydrocarbons with 3 to 12 carbon atoms, halogenated hydrocarbons with 1 to 5 carbon atoms or halogenated ethers with a total of 2 to 6 carbon atoms, or consisting of these. In this case, ethanol and isopropanol are particularly preferred as alcohols. Examples of aliphatic hydrocarbons are pentane, hexane, heptane, as well as gasoline fractions, in particular light gasoline with a boiling point in the range from 15 to 80 ° C. Lower-boiling fractions, such as, for example, propane and / or butane, liquefied under pressure, can also be used as liquid components of the blowing agents. Examples of cyclic hydrocarbons are cycloaliphatic hydrocarbons, preferably cyclopropane, cyclopentane and cyclohexane. By halogenated hydrocarbons we mean hydrogen-containing fluorohydrocarbons. Examples of fluorohydrocarbons are pentafluoroethane (R125), 1,1,1,2-tetrafluoroethane (R134a), 1,1,1-trifluoroethane (R143a), 1,1,2-trifluoroethane (R143), 1,1-difluoroethane ( R152a), 1,1,1,3,3-pentafluoropropane (R245fa), octafluoro-ropropane (R218), or also 1,1,1,3,3-pentafluorobutane (R365mfc). By halogenated ethers we mean hydrogen-containing fluorochloro- or fluoroethers, such as, for example, difluoromethoxy-2,2,2-trifluoroethane (E245).

Preferably, a blowing agent composition is used which contains 10 to 20 parts by weight of liquefied carbon dioxide and 30 to 90 parts by weight of at least one halogenated hydrocarbon or an aliphatic hydrocarbon or a halogenated ether or which consists of the quoted mixture.

Especially preferably, in the process according to the present invention a blowing agent composition is used which contains 10 to 20 parts by weight of liquefied carbon dioxide and 30 to 90 parts by weight of 1,1-difluoroethane (152a) or which consists of them. Similarly, a blowing agent composition containing 10 to 20 parts by weight of liquefied carbon dioxide, 50 to 70 parts by weight of 1,1-difluoroethane (R152a) and 20 to 35 parts by weight of ethanol or consisting of the mixture. Among the compositions according to the invention containing halogenated ethers, blowing agent mixtures containing 10 to 20 parts by weight of liquefied carbon dioxide and 80 to 90 parts by weight of difluoromethoxy-2,2,2-trifluoroethane are particularly preferred. (E245) or consisting of these mixtures. Of the aliphatic hydrocarbons, n-pentane is particularly preferred. Preferably, a composition according to the invention including aliphatic hydrocarbons should contain 10 to 20 parts by weight of liquefied carbon dioxide and 80 to 90 parts by weight of n-pentane, as well as optionally, additionally, 1 to 3 parts. by weight of water, or consist of this mixture.

In all these blowing agent mixtures, the amount of the other blowing agents used can be reduced.

ES 2 117 451 T5 expansion through the use of liquid CO2. CO2 is harmless from a physiological point of view and is not polluting.

Advantageously, the process according to the invention for the production of foamed plastics can be carried out as a casting process or an extrusion process. extrusion process. In the extrusion process, suitable mixtures are directly extruded for the production of foamed plastics into foamed sheets, foils, shaped bodies, profiles or particles. In a particularly preferred manner, foamed thermoplastic plastics, in particular polyethylene, polypropylene or polystyrene foamed materials, are produced according to the invention. According to the invention, the process is carried out in such a way that in a melt of the starting materials suitable for the production of foamed plastics, the composition of the liquefied carbon dioxide blowing agent and another blowing agent are mixed. physical liquid and the polymerization of the starting materials for the foamed synthetic material to be manufactured is carried out, eventually maintaining a slight depression or overpressure during the foaming process. For the process according to the invention, it is possible to use processing plants known per se, for example extruder plants. In this case, it is particularly surprising that, with the process according to the invention, it is possible to introduce carbon dioxide in a liquefied state, also at high temperature, into the extruder for the purpose of foaming thermoplastic polymer melts. In contrast to the methods hitherto known from the state of the art, a problem-free metering of carbon dioxide is thus possible. According to the process according to the invention, it is thus possible to produce highly homogeneous predominantly closed cell structure foam materials using carbon dioxide. Furthermore, the foamed synthetic materials, obtained following the process according to the invention, are distinguished by a high thermal insulation capacity.

The process according to the invention for the production of foamed plastics can be carried out in such a way that a blowing agent composition prepared in advance in a pressure vessel is used, which has been prepared by placing in a pressure vessel liquid or liquefied physical blowing agents under pressure in the desired proportions by weight and introducing under pressure, in a manner known per se, liquefied carbon dioxide under pressure in the desired quantity. However, according to the process according to the invention, it is also possible to proceed in such a way that the blowing agent composition to be used is prepared immediately before the foaming process of the polymers to be foamed or of the polymerizable components. In this case, liquefied carbon dioxide is introduced in the corresponding quantities into a pressure vessel, outside the extruder installation itself, in the other liquid component of the blowing agent at a pressure under which the carbon dioxide is It is in a liquid state, whereby the components mix widely with each other. The homogeneous mixture thus obtained of liquefied carbon dioxide and liquid blowing components is then introduced into the extruder installation through an inlet for liquid blowing agents.

The process according to the invention is suitable for the production of hard or soft foamed materials, both open and closed cells. The process is particularly suitable for manufacturing foamed polyurethane synthetics. For this purpose, known per se PUR production plants can be used, for example high pressure or low pressure mixing plants, which are equipped with the known static mixers according to the state of the art.

In a variant for the production of foamed PUR synthetic materials, the blowing agents can contain, as one more component, together with the carbon dioxide liquefied under pressure and one or more liquid and / or pressure liquefied physical blowing agents, still other liquid additives, for example flame retardants. Ordinary flame retardants are, for example, phosphoric esters or phosphonates. The corresponding phosphoric esters and phosphonic esters which contain three lower alkyl groups or three lower alkyl groups substituted with one or more halogen atoms are particularly well suited. Lower alkyl preferably means C1 to C4 groups. Suitable examples are tris-chloroisopropyl phosphate, trichloroisopropyl phosphate, trischlorethyl phosphate, trichloroethyl phosphate, trichloropropyl phosphate, tris-chloropropyl phosphate, triethyl phosphate, dimethyl isopropyl phosphate or trischlorethyl phosphate, triethyl phosphate or triethyl phosphate dimethylmethyl.

If the process according to the invention is used to produce foamed PUR plastics, then all customary foaming raw materials can be used, such as, for example, aliphatic, cycloaliphatic or aromatic di- or polyisocyanates. Examples of foaming raw materials are, for example, 2,4- and 2,6-toluene diisocyanate, diphenylmethane diisocyanate, polymethylene polyphenylisocyanate and mixtures thereof. Polyisocyanates containing carbodiimide groups, urethane groups, allophanate groups, isocyanurate groups, urea groups or biuret groups, which are designated as "modified polyisocyanates" or "isocyanate prepolymers" can also be used. In the manufacture of foamed PUR synthetic materials, polyisocyanates are usually reacted with compounds containing at least two hydrogen atoms capable of reacting with isocyanate groups, for example compounds containing hydroxyl groups based on polyester, polyether and amine, as well as compounds that have amino and / or carboxyl and / or thiol groups. In addition, all the catalysts used in the manufacture of foamed PUR plastics can be used, such as, for example, tertiary amines and / or organic metal compounds such as, for example, tin salts of carboxylic acids.

If the process according to the invention is used to produce polystyrene or polyethylene foams, all known foam raw materials can also be used for this.

IS 2 117 451 T5

In a manner known per se, all additives or adjuvants known per se, for example nucleating agents, pore-regulating substances, flame retardants, antistatics, stabilizers, plasticizers, can be added in addition to the polymers and / or polymerizable components. crosslinking agents, fillers or colorants.

Another embodiment of the invention relates to the manufacture of one-component or multi-component PUR foams from pressure vessels, which is explained below. Also in this case, a blowing agent composition is used which contains 5 to 50% by weight of liquefied CO2.

By blowing agent composition is meant the liquid fraction of the blowing agent composition enclosed in the pressure vessel, including the gaseous phase found in said pressure vessel.

In this variant, the blowing agent composition contains, together with the liquid CO2, at least one other liquid component. As another liquid component, for example, a physical blowing agent liquid or liquefied under pressure may be contained. Halogenated blowing agents are well suited, halogen-free blowing agents are often non-polluting and are to be preferred. According to a particularly advantageous variant, liquid CO2 is contained as the sole blowing agent and the other liquid component consists of a liquid flame retardant from the group of phosphoric acid esters or phosphonic acid esters.

As other liquid components, in addition to carbon dioxide liquefied under pressure, all the usual liquid physical blowing agents are possible, namely easily volatile organic compounds, such as ether, acetone, hydrocarbons such as pentane, heptane, hexane, gasoline mixtures , halogenated hydrocarbons or halogenated ethers. In addition to the liquefied carbon dioxide, gases liquefied under pressure, such as, for example, propane or butane, can also be used.

Preferably, the blowing agent compositions contain more than 5% by weight, in particular 5 to 50, for example 5 or 10 to 30% by weight of liquefied carbon dioxide.

Blending agent compositions containing 10 to 50 parts by weight of liquefied carbon dioxide and 30 to 90 parts by weight of at least one liquid or pressure-liquefied blowing agent from the group of ethers with a total of 2 to 4 carbon atoms, ketones with 3 to 5 carbon atoms, aliphatic hydrocarbons with 2 to 12 carbon atoms, of halogenated hydrocarbons with 1 to 5 carbon atoms or of halogenated ethers with a total of 2 to 6 carbon atoms, or consisting of such a mixture. Examples of aliphatic hydrocarbons are pentane, hexane, heptane, as well as gasoline fractions, in particular light gasoline with a boiling point in the range from 15 to 80 ° C. The low boiling point fractions, such as, for example, propane and / or butane, are preferably used in liquefied form under pressure. Examples of cyclic hydrocarbons are cyclopropane, cyclopentane, and cyclohexane. By halogenated hydrocarbons we mean hydrogen-containing fluorohydrocarbons. Examples of fluorohydrocarbons are pentafluoroethane (R125), 1,1,1,2-tetrafluoroethane (R134a), 1,1,1-trifluoroethane (R143a), 1,1,2-trifluoroethane (R143), 1,1-difluoroethane ( R152a), 1,1,1,3,3-pentafluoropropane (R245fa), octafluoropropane (R218) or 1,1,1,3,3-pentafluorobutane (R365mfc). By halogenated ethers we mean hydrogen-containing fluorochloroethers or fluoroethers, such as, for example, difluoromethoxy-2,2,2-trifluoroethane (E245). Examples of possible ethers are dimethyl ether or diethyl ether. Of the ketones, acetone is particularly preferred.

The blowing agent compositions may be free of halogenated blowing agents and consist solely of liquefied carbon dioxide as the only component of the blowing agent. Mixtures containing liquefied carbon dioxide in a ratio of 20 to 30 parts by weight and butane or a mixture of propane / butane in a ratio of 50 to 60 parts by weight and / or acetone in a ratio of 5 to 15 parts are preferred. by weight, or they consist of these components. The propane / butane mixture used can be a conventional mixture, for example a mixture with a vapor pressure of about 3.7 bar (abs.).

Furthermore, blowing agent compositions containing 10 to 50 parts by weight of liquefied carbon dioxide and 10 to 90 parts by weight of a halogenated hydrocarbon or a halogenated ether, or consisting of these components, are preferred. In this case, blowing agent compositions containing 10 to 30 parts by weight of liquefied carbon dioxide and, of the halogenated hydrocarbons, 10 to 90 parts by weight of 1,1-difluoroethane (R152a), or which they consist of these components. Among the compositions containing halogenated ethers, blowing agent compositions containing 15 to 40 parts by weight of liquefied carbon dioxide and 10 to 20 parts by weight of difluoromethoxy-2,2,2-trifluoroethane (E245) are particularly preferred. , or consisting of these components.

In another particularly preferred variant, the blowing agents can contain, in addition to carbon dioxide liquefied under pressure as a liquid component, customary phosphate esters or phosphonates as flame retardants. Particularly suitable are phosphatic or phosphonic esters containing three C1 to C4 alkyl groups, which are optionally substituted with one or more halogen atoms, such as, for example, trischloroisopropyl phosphate, trischlorethyl phosphate, trichloroethyl phosphate, trichloropropyl phosphate, phosphate triethyl, dimethylethyl phosphate, tris-dichloroisopropyl phosphate or dimethylmethyl phosphonate. Conveniently, the concentrations are in this case 10 to 50 parts by weight of liquefied carbon dioxide and 80 to 100 parts by weight of phosphate ester or phosphonate. Trischloropropyl phosphate is preferably used. These special blowing agent compositions

They are free of blowing agents other than CO2 and are therefore particularly non-polluting.

The blowing agent compositions are suitable for producing all hitherto known PUR foams from pressure vessels, in particular for foaming 1K and 2K PUR materials (K = component). The blowing agent compositions can also be used for the manufacture of multi-component PUR foams in which the foam formers are charged with more than one reactive component separately in a pressure vessel. Also to manufacture the so-called 1.5K PUR foams, in which, unlike 2K foams, an amount of the polyol component not sufficient for the reaction of the isocyanate groups is added to the prepolymer, shortly before dispersing, blowing agent compositions can be used.

The blowing agent compositions have proven very advantageous for making 1K or 2K PUR foams.

The 1K PUR foam mixture to be foamed may contain, together with the blowing agent composition, in a manner known per se and as other components, a polyol component, a polyisocyanate component, a catalyst, etc. as optionally still a flame retardant agent as an auxiliary agent.

The 1K PUR foamed mixture may contain as polyol components, for example, glycerol, glycols or polyether polyols, which were obtained as addition products of propylene oxide or ethylene oxide in polyhydric alcohols, water or ethylenediamine, or polyester polyols, which were obtained as polycondensation products from polyols with dicarboxylic acids or their anhydrides, or mixtures thereof. A typical polyol component can be, for example, a mixture of a brominated polyether polyol (eg diol or triol) with a hydroxyl number of 200 to 350 and a polyether polyol (eg a diol) with an index hydroxyl value of 110. Furthermore, modified vegetable oils with an OH number in the range of 100 to 300 are also possible, for example castor oil.

As polyisocyanate components, it is possible to use, for example, diphenylmethane 4,4'-diisocyanate, diisocyanate-toluene, 1,5-diisocyanate-naphthalene, triisocyanate-triphenylmethane, 1,6-diisocyanate-hexane, preferably diphenylmethane-4,4 ' -diisocyanate, or mixtures thereof.

Typical catalysts in 1K PUR foam mixtures which can be foamed in the process according to the invention with a composition of blowing agents organic amines, amino alcohols or amino ethers, for example 2-dimethylaminoethyl-3-dimethylaminopropylether, diethanolamine, dimethylcyclohexylamine, 2 -dimethylaminoethyl ether or morpholine compounds such as for example 2,2-dimorpholinodiethyl ether, N, N-dimethylamino-morpholine, N-methylmorpholine. Morpholine compounds are preferred, in particular 2,2-dimorpholinodiethyl ether.

As customary flame retardants, it is possible to use trisdichloroisopropyl phosphate, trichloroisopropyl phosphate, trischlorethyl phosphate, trichlorethyl phosphate, trischloropropyl phosphate, trichloropropyl phosphate, dimethyl ethyl phosphate, dimethyl isopropyl phosphate, preferably dimethyl isopropyl phosphate, dimethyl isopropyl phosphate, dimethyl isopropyl phosphate, preferably dimethyl isopropyl phosphate. trischloropropyl.

Suitable stabilizers are, for example, siloxane copolymers.

A 1K PUR foaming mixture contains, based on the foaming mixture as 100% by weight, for example 20 to 30% by weight of a polyol component, 40 to 60% by weight of polyisocyanate component, 0.1 to 3% by weight of catalyst, optionally 10 to 15% by weight of a flame retardant, optionally 1 to 2% by weight of a foam stabilizer together with 15 to 35% by weight of the blowing agent composition. A typical mixture of 1K PUR foams, which can be advantageously foamed with the aid of the blowing agent composition, thus consists, for example, of about 22.5% by weight of a polyol component, for example of a mixture of a brominated polyether polyol with a hydroxyl number of 200 to 350 and of a polyether polyol with a hydroxyl number of 110 in a mixing ratio of 1: 1, about 42.5% by weight of a polyisocyanate component, for example diphenylmethane-4,4'-diisocyanate, about 0.5% by weight of a catalytic substance, such as for example 2.2, dimorpholinodiethyl ether, about 1.5% by weight of silicone foam stabilizer, about 13% by weight of a flame retardant agent, such as, for example, trischloropropyl phosphate, and a portion of about 20% by weight of the blowing agent composition. From such a 1K PUR foamed mixture a one-component foamed material can be manufactured having a homogeneous fine cell structure and a low bulk density, for example a bulk density of about 23 to 25 kg / m³ .

1.5K and 2K PUR foams are distinguished from single-component foamed materials in that the polyol component, necessary for curing the foam, is kept separate from the prepolymer composition and is only added to the prepolymer immediately before of foaming. In this case, all the polyol components already mentioned come into consideration as the second component. For faster curing, the second component may additionally contain an ordinary catalyst, for example the aforementioned amine or morpholine compounds or also organometallic compounds such as, for example, tin dioctoate, cobalt naphthenate, dibutyltin dilaurate or iron acetonylacetate.

IS 2 117 451 T5

The one-component or multi-component PUR foamed materials made with the blowing agent compositions show very good thermal insulating ability and are therefore well suited for damping purposes, for example in the construction or home field. Polyurethane spray adhesive blowing agent compositions are also suitable.

The invention further comprises a process for manufacturing a 1K or 2K PUR foam material, in which a PUR foam material is manufactured from a pressure vessel containing a mixture of PUR foam based on a polyol component, a prepolymer that contains isocyanate groups, a catalyst and optionally other customary adjuvants, as well as one of the blowing agent compositions described above, by relieving the overpressure in the pressure vessel to atmospheric pressure through a valve. The corresponding pressure vessels, as well as the appropriate valves for foaming, are generally known.

The invention further relates to mixtures of PUR foams of one or more components, intended for the production of a PUR foam material from pressure vessels, containing one of the blowing agent compositions described above.

Another object of the invention is a process for preparing a blowing agent composition for the production of PUR foam materials from pressure vessels, in which liquefied carbon dioxide is used as a blowing agent component. In the process according to the invention, the physical blowing agent component, liquid or liquefied under pressure, is placed in a pressure vessel in the desired parts by weight, and liquefied carbon dioxide is injected in the desired quantity in a manner known per se, normally blended under pressure. This blowing agent composition prepared according to the invention can then be injected in the desired quantity into a pressure container (aerosol can), which already contains the prepolymer and optionally all the other components. In this case, the amount of carbon dioxide is regulated only by the pressure allowed for the aerosol cans (10 to 18 bars).

According to the invention it is then possible to manufacture pressure vessels containing mixtures of PUR foam material, which can contain about 20 to 30 g of carbon dioxide per kg of can. According to the processes used up to now, in which gaseous carbon dioxide was always used, until now it was only possible to introduce about 3 to 5 g of carbon dioxide per kg of can. Advantageously, according to the invention it is now possible to further reduce, in the manufacture of PUR foamed materials from pressure vessels, the proportion of combustible, liquid or pressure-liquefied physical blowing agents. From the point of view of costs, a reduction of the physical, liquid or pressure-liquefied blowing agents, usual until now, is also of extraordinary advantage. The one-component or multi-component PUR foams produced with the blowing agent composition according to the invention have a very homogeneous, predominantly closed-cell, fine-cell structure as well as a very high thermal insulation capacity. Correspondingly, PUR foamed materials, manufactured with a blowing agent composition according to the invention, are particularly suitable for damping purposes in the building and residential sector.

The following Examples are to explain the invention in greater detail, without limiting its scope.

Examples

1. Manufacture of a polystyrene foam material

a) Liquefied carbon dioxide / R152a as blowing agent

200 kg of polystyrene (melt index 3.0-110) was mixed with 2 kg of talc as a nucleating agent, and this mixture was metered into an ordinary extruder installation and melted. Approximately 6% by weight, based on the polystyrene, of a blowing agent were metered into the polystyrene melt in the melt zone of the extruder through an injection nozzle. The blowing agent composition contained 14 parts by weight of liquefied carbon dioxide and 86 parts by weight of R152a. The vapor pressure of this blowing agent composition was about 14 bar at 20 ° C.

In the mixing zone, the polystyrene melt was homogeneously mixed with the blowing agent composition and the mixture thus obtained was then extruded through a nozzle. A homogeneous, closed-cell structure foam material was obtained.

According to the invention, both polystyrene foam sheets and polystyrene foam sheets were produced. A polystyrene foamed sheet made according to the invention had a density of approximately 35 kg / m³ and a foamed polystyrene plate, manufactured according to the invention, had a density of approximately 33 kg / m³.

IS 2 117 451 T5

b) Liquefied carbon dioxide / R152a / ethanol as a blowing agent

As described in Example 1a), about 8.5% by weight, based on the polystyrene, of the blowing agent was metered into a polystyrene melt. The blowing agent composition contained 14 parts by weight of liquefied carbon dioxide, 57 parts by weight of R152a and 29 parts by weight of ethanol.

The vapor pressure of these blowing agent compositions was about 15 bar at 20 ° C.

A polystyrene foamed sheet made according to the invention had a density of approximately 36 kg / m³ and a polystyrene foam plate made according to the invention had a density of approximately kg / m³.

two. Manufacture of a polyethylene foam material (not according to the invention) a) Liquefied carbon dioxide / R152a / R141b as blowing agent

200 g of polyethylene (melt index 3.5-150) were extruded under identical conditions to those described in Example 1 for the polystyrene foamed material. Approximately 6% by weight, based on polyethylene, of a mixture of blowing agents was metered in. A blowing agent composition based on 14 parts by weight of liquefied carbon dioxide, 50 parts by weight of R152a and 36 parts by weight of R141b was used. A fine cell polyethylene foam with low shrinkage was obtained. The manufactured polyethylene foamed tube had a density of approximately 40 kg / m³.

3. Manufacture of a PUR foam material

To manufacture the PUR foam material, a polyol mixture consisting of 40 parts by weight of a polyether of ethylenediamine / propylene oxide (OH number 480), 60 parts by weight of polyether was used as one of the starting components. of sorbitol / glycerol / propylene oxide (OH number 490), 1 part by weight of foam stabilizer (type DC193 from Dow Corning Corporation) and 1.5 parts by weight of dimethylcyclohexylamine. Diphenylmethane diisocyanate was used as the isocyanate component in a stoichiometric ratio increased by 10%. The PUR foamed materials were manufactured in a low-pressure facility with an output throughput of approximately 8 kg / min, making 3-component dispensing possible. A static mixer was used as the mixing apparatus.

a) Liquefied carbon dioxide / R141b / water as blowing agent (not according to the invention)

A blowing agent composition was used in an amount of 30 parts by weight. The blowing agent composition consisted of 13.9 parts by weight of liquefied carbon dioxide, 85.1 parts by weight of R141b, and additionally 1 part by weight of water. With this composition of blowing agents, a PUR hard foamed material with a fine cell structure and a density of approximately 24 kg / m was manufactured.³.

b) Liquefied carbon dioxide / n-pentane / water as a blowing agent

In addition, a PUR foam was manufactured with 18 parts by weight of a blowing agent composition. This blowing agent composition consisted of 13.9 parts by weight of liquefied carbon dioxide and 85.1 parts by weight of n-pentane and additionally 1 part by weight of water. With this composition of blowing agents, a PUR hard foamed material with a fine cell structure and a density of approximately 25.4 kg / m was obtained.³.

c) Liquefied carbon dioxide / E245 as blowing agent

In addition, a PUR foam was manufactured with 35 parts by weight of a blowing agent composition. This blowing agent composition consisted of 14 parts by weight of liquefied carbon dioxide and 85 parts by weight of E245. With this composition of blowing agents, a hard PUR foam with a fine cell structure and a density of approximately 33.5 kg / m was obtained.³.

Four. Liquefied carbon dioxide / propane / butane / acetone as a blowing agent for 1K PUR foamed materials

a) 247 g of a polyol premix, consisting of 73 g of polyether polyol (diol), brominated, OH number about 240 g of polyether polyol (diol), OH number about 110 g of trischloropropyl phosphate, g of silicone foam stabilizer, g of dimorpholine diethyl ether,

ES 2 117 451 T5 were placed in an aluminum aerosol can with a volume of 1000 cm³ . 356 g of diphenylmethane4,4-diisocyanate was added and the aerosol canister was closed with a valve for the foam aerosol. A blowing agent composition according to the invention was prepared by placing 62 g of pressure liquefied propane / butane and 10 g of acetone in a pressure vessel and adding 28 g of pressure liquefied carbon dioxide with mixing. 99 g of this blowing agent composition according to the invention was then injected into the aerosol can containing the foam components through a conventional aerosol filling device. The aerosol can was briefly shaken and allowed to stand for approximately 24 hours for the prepolymer to form. After this time, the 1K PUR foam mixture was ready for use.

The 1K PUR foamed mixture was expelled from the aerosol can by means of the blowing agent composition according to the invention. A PUR foam material was obtained with a gross density of approximately 23 kg / m³ , with a homogeneous structure of fine cells. After storage for 7 days at an air humidity of about 90%, the shrinkage of the PUR foam averaged about 5 percent in length.

b) As described in a), a mixture of polyols and a polyisocyanate was introduced into an aerosol can of the same volume. The blowing agent composition according to the invention used was a composition of 50 g of propane / butane, 7.5 g of acetone and 20 g of liquefied carbon dioxide. Preparation of the blowing agent composition and filling into the aerosol can took place as described in a).

The PUR foam material manufactured with this blowing agent composition according to the invention exhibited a gross density of approximately 25 kg / m³ .

5. Liquefied carbon dioxide / propane / butane / R141b as blowing agent for 1K PUR foamed materials (not according to the invention)

As described in Example 4, an aerosol can with a volume of 1000 cm was filled³ with a mixture of polyol and a polyisocyanate. The blowing agent composition used was a composition of 62 g of propane / butane, 10 g of R141b and 28 g of liquefied carbon dioxide. The preparation of the blowing agent composition and its loading into the aerosol can took place as described in Example 4.

The PUR foamed material made with this blowing agent composition exhibited a gross density of approximately 25 kg / m³ .

6. Liquefied carbon dioxide / trichloropropyl phosphate / R141b as blowing agent for 1K PUR foam materials (not according to the invention)

An aerosol can with a volume of 1000 cm was filled³ with 214 g of a mixture of polyols and 356 g of polyisocyanate, as described in Example 4. A composition according to the invention was prepared by placing 100 g of trischloropropyl phosphate and 10 g of R141b in a pressure vessel and adding 28 g of liquefied carbon dioxide under pressure with mixing. As described in Example 4, the aerosol can was filled with 99 g of this blowing agent composition.