KR20140052022A - Method for producing rigid polyurethane foams - Google Patents

Abstract

The present invention relates to a particle-containing polyurethane foam in which the particles are predominantly incorporated into the bubble wall.

Description

METHOD FOR PRODUCING RIGID POLYURETHANE FOAMS [0002]

The present invention relates to a process for preparing a rigid polyurethane foam by reacting a polyisocyanate with a compound having at least two hydrogen atoms which are reactive towards isocyanate groups.

Rigid polyurethane foams have been known for a long time and are frequently described in the literature. This is usually prepared by reacting a polyisocyanate with a compound having two or more hydrogen atoms that are reactive toward isocyanate groups, especially a polyfunctional alcohol. Rigid polyurethane foam is preferably used for damping of refrigeration appliances or building members.

Improving the properties of rigid polyurethane foam is an ongoing challenge. In particular, the thermal conductivity of the foam must be reduced and its mechanical properties, especially the compressive strength, must be improved.

One possible way to achieve this goal is to use filler-containing polyols in the production of rigid foams. Frequently used groups for filler-containing polyols are those prepared by in-situ polymerization of polyols, especially olefinically unsaturated monomers in polyether alcohols, especially styrene and / or acrylonitrile. These products are generally known and are referred to as polymer polyols or graft polyols.

Rigid polyurethane foams prepared using graft polyols are described, for example, in WO2005 / 097863 and WO2004 / 035650. The rigid foams described in this document exhibit short demolding times, good mechanical properties and low thermal conductivity.

The uniform distribution of particles in the foam matrix is important for the properties of the foam. An excellent distribution means that in the first step no aggregate composed of a plurality of particles is formed and instead the filler is uniformly distributed in the polymer material. Only in this way can the filler be used in an economically feasible manner. The distribution of such particles can be achieved, for example, using graft polyols such as those described in WO2005 / 097863 and WO2004 / 035650.

In addition to avoiding agglomerates, additions are important to the distribution of the particles in the foam: Usually, more than 80% of the polyurethane material is present in the cell strut of the rigid foam (DW Reitz, MA Schuetz, LR Glicksman &Quot; A basic study of aging of foam insulation ", Journal of cellular plastics, 1984, 20 (2), 104-113). Thus, substantially all of the particles are also present in the bubble column and only a few filler particles are also found in the bubble walls. When the foam is subjected to high mechanical compression or tensile stresses, the material begins to break at a point of weakness, i.e., a very thin bubble wall, while a significantly stronger bubble column initially remains intact. In order to achieve reinforcement of the foam by the filler, a very large proportion of the filler needs to be present in the bubble wall, since only that part of the filler used has reinforcement action. According to the prior art, this distribution of fillers with increased concentration of particles in the bubble wall is not known.

The use of fillers to optimize the properties of rigid polyurethane foams requires substantial control of the distribution of individual particles within the foam.

It is an object of the present invention to provide polyurethane foams, especially rigid polyurethane foams, which exhibit excellent mechanical properties, low thermal conductivity, and excellent processing properties, for example reduced release time. In particular, the compressive strength of the foam which allows to reduce the density of the foam should be improved. Furthermore, a high compatibility with the foaming agent and, in particular, with the starting components for the production of polyurethanes, in particular with non-polar hydrocarbons, in particular with polyol components, has also to be achieved.

This object is met surprisingly by the fact that the particles are mainly incorporated into the bubble walls of the foam, wherein the particles are polymeric or inorganic particles of an olefinically unsaturated monomer, the surface of which is modified by a surface active material.

The present invention thus provides a particle-containing polyurethane foam in which the particles are mainly entrained in a bubble wall, wherein the particles are polymers or inorganic particles of an olefinically unsaturated monomer, the surface of which is modified by a surface active material.

As used herein, the term "primarily" means that at least 50 wt% of the particles are incorporated into the bubble wall, based on the total weight of the particles.

The present invention further relates to a process for preparing a rigid polyurethane foam by reacting a polyisocyanate (a) and a compound (b) having two or more hydrogen atoms reactive with an isocyanate group in the presence of a foaming agent (c) ) Or (b) comprises particles whose surface is modified by a surface-active substance.

The present invention further provides particle-containing polyether alcohols which can be prepared by in situ polymerization of olefinically unsaturated monomers in polyether alcohols, wherein at least one olefinically unsaturated monomer has surface-active properties do.

The present invention further provides a process for preparing particle-containing polyether alcohols by in situ polymerization of olefinically unsaturated monomers in polyether alcohols, wherein at least one olefinically unsaturated monomer has surface-active properties.

For purposes of the present invention, surface activity means that the compound is compatible with immiscible materials, particularly incompatible liquids or immiscible liquids and gases. These compounds have groups that are compatible with one material and compatible with other materials. Thus, the surface active compound is attached to the interface between the incompatible materials.

The particles preferably have a size of less than 50 [mu] m, in particular in the range of 0.5 to 10 [mu] m.

The particles are preferably selected from the group consisting of organic particles such as organic polymers or thermoplastic particles and inorganic particles, especially carbon-rich particles such as carbon black or graphite, or oxides, especially inorganic oxides.

As mentioned above, the surface of the particles has surface-active properties because the particles have been modified by using surface active materials. This can be induced, in particular, by applying a surfactant to the surface of the particles. Attachment of the surfactant to the particles may take place via non-covalent or preferably via covalent bonds.

In a preferred embodiment of the present invention, the particles are inorganic particles. The particles are preferably the above-mentioned carbon-rich particles, such as carbon black or graphite, or inorganic oxides, especially metal oxides.

In the case of inorganic particles, the surfactant preferably comes into contact with the particles in such a way that the surfactant adheres to the surface of the particles.

In a further preferred embodiment of the present invention, the particles are polymers of olefinically unsaturated monomers.

In this case, the particles may be thermoplastic particles dispersed in component (a) or preferably (b). Such a process, also known as a melt emulsion process, is known and described, for example, in WO 2009/138379.

Also here, the surfactant is brought into contact with the particles, preferably in a manner such that the surfactant adheres to the surface of the particles, as in the case of inorganic particles.

In a particularly preferred embodiment of the present invention, the particles are prepared by in situ polymerization of olefinically unsaturated monomers in polyols, especially polyether alcohols. Polyols prepared by this process are generally known and are sometimes referred to as graft polyols.

The synthesis of the graft polyols by the two processes is well known and is described in a number of embodiments. Thus, the synthesis of graft polyols by a semi-batch process is described in the following patent documents: EP 439755 and U.S. Pat. 4522976. A particular form of the semi-batch process is a semi-batch seed process in which the graft polyol is additionally used as a seed in the initial charge of the reaction, for example as described in EP 510533 and EP 698628. The synthesis of graft polyols by a continuous process is likewise known and is described in WO 00/59971 and WO 99/31160 among others.

In the case of organic particles prepared by in situ polymerization of olefinically unsaturated monomers in organic particles produced by polymerization, in particular polyether alcohols, the surfactant is preferably incorporated into the particles by means of one or more monomers having a surfactant and at least one olefin group .

Such monomers can be prepared by reacting a surfactant having at least one reactive group with a compound having an olefinically unsaturated group and a group reactive with the group.

It is desirable to use a surfactant that compatibilizes the liquid and the gas with non-porous interactions. These compounds are often used as foam stabilizers in the manufacture of polyurethanes.

Preferred examples of such surfactants are polyether siloxanes having at least one side chain having at least one hydroxyl group, for example polyether siloxanes of the formula:

Wherein R is an alkyl group having from 1 to 10 carbon atoms and M is an alkyl group having from 2 to 10 carbon atoms which is bonded to the polyether chain via an ether, ester, urethane or acetal group, wherein x, y, z, n and m are numbers, Aromatic or araliphatic group having one to twenty carbon atoms. The sum of x, y and z is preferably selected so that the molecular weight of the siloxane chain in the compound is, for example, 2000 to 6000 g / mol, preferably 4000 to 5500 g / mol. z is preferably 1 or 0, an average of 0.9, and y is preferably in the range of 3 to 20. x is defined here. n and m are preferably selected according to the invention so that the side chain has a molecular weight of from 400 to 2500 g / mol. The ratio n / (n + m) is preferably in the range of 10 to 90%, and the value m / (n + m) is preferably similar.

The present invention therefore provides a process of the present invention wherein a polyether siloxane having at least one side chain, preferably having at least one hydroxyl group, is used as a surfactant.

Further, the present invention preferably provides a foam of the present invention wherein the surface-active substance is a polyether siloxane having at least one side chain having at least one hydroxyl group.

Further, the present invention preferably provides a particle-containing polyether alcohol of the present invention which can be prepared by in situ polymerization of olefinically unsaturated monomers in polyether alcohols, wherein the at least one olefinically unsaturated monomer comprises at least one hydro- Have surface active properties as a result of the use of polyether siloxanes having at least one side chain with a lock group.

The present invention also preferably provides a process of the present invention for preparing a particle-containing polyether alcohol by in situ polymerization of olefinically unsaturated monomers in polyether alcohols, wherein the at least one olefinically unsaturated monomer comprises at least one hydroxyl group Lt; RTI ID = 0.0 > polyether < / RTI >

The molecular weight of the siloxane chain in this compound is, for example, 2000 to 6000 g / mol, preferably 4000 to 5500 g / mol. The molecular weight of this compound is, for example, 10,000 to 25,000 g / mol, preferably 11,000 to 22,000 g / mol, particularly preferably 11,000 to 20,000 g / mol.

The hydroxyl group may be reacted with an unsaturated compound having at least one group reactive with the isocyanate group. This group may be an acid group or an acid anhydride group. Examples of such unsaturated acids and acid derivatives include maleic anhydride (MAn), fumaric acid, acrylate derivatives and methacrylate derivatives. MAn is preferred. This group may preferably be an isocyanate group, since the urethane group produced is more stable in hydrolysis than the ester group. Examples of unsaturated isocyanates include 3-isopropenyl-1,1-dimethylbenzylisocyanate (TMI) and isocyanatoethyl methacrylate, with TMI being preferred. These compounds having olefinically unsaturated groups are often referred to as macromers or stabilizers.

The additional tackifier itself, which may be used instead of, or preferably in combination with, the above described compounds is a linear or branched polyetherol having a reactive olefinic unsaturation, usually having a molecular weight Mw of 1000 g / mol and at least one normal terminal . Ethylenically unsaturated groups include ethylenically unsaturated carboxylic acids and / or carboxylic acid anhydrides such as maleic anhydride, fumaric acid, acrylate and methacrylate derivatives and also unsaturated isocyanate derivatives such as 3-isopropenyl-1,1-dimethylbenzyl Can be inserted into the existing polyol by reaction with isocyanate, isocyanatoethyl methacrylate. Another method is the preparation of polyols by alkoxylation and ethylenic unsaturation of propylene oxide and ethylene oxide using initiator molecules having hydroxyl groups.

Examples of such herbs are U.S. Pat. 4390645, U.S. Pat. 5364906, and U.S. Pat. Lt; / RTI >

Surfactants can be incorporated into the blend itself.

In a further embodiment of the present invention, the graft polyols are prepared by in situ polymerization of olefinically unsaturated monomers in polyether alcohols, wherein the graft particles are modified by reaction with a surface active component after it is prepared.

In one embodiment of the present invention, the surfactant does not comprise any halogen atoms and in particular does not contain any fluorine atoms.

This monomer is attached to the surface of the particles in the preparation of the graft polyol.

As a result, the particles behave like surface active materials.

The surface active particles used according to the present invention may additionally have functional groups, which allow the particles to chemically bond to the PU matrix via their functional groups. However, it is also possible that the particles according to the invention do not have reactive functional groups on the surface.

As mentioned above, the foams of the present invention are prepared by reacting a polyisocyanate (a) with a compound (b) containing at least two hydrogen atoms which are reactive toward isocyanate groups, Preferably, component (b) comprises particles.

The incorporation of particles into component (a) is less desirable, because the higher reactivity of the polyisocyanate can lead to malfunctions and undesirable secondary reactions.

Therefore, component (b) preferably comprises particles whose surface is modified with a surface-active substance.

Particle-containing polyols, especially polyether alcohols, as described, can be prepared in a preferred embodiment by in situ polymerization of olefinically unsaturated monomers in polyether alcohols, often referred to as carrier polyols. This polyol is often referred to as a graft polyol.

The carrier polyol is preferably prepared by addition of an alkylene oxide, especially an ethylene oxide and / or propylene oxide, to the H-functional compound, preferably a compound having a hydroxyl or amino group. The H-functional compound may be an alcohol having 2 to 4 hydroxyl groups in the molecule. Preferred examples are glycerol, trimethylol propane, and glycols such as ethylene glycol, diethylene glycol, propylene glycol and dipropylene glycol. In a further embodiment of the invention, the H-functional compound is a primary or secondary amine having 2 to 4 reactive hydrogen atoms. Examples of aliphatic amines include ethylenediamine, propylenediamine, and ethanolamine. It is preferred to use aromatic amines, preferably toluene diamines, in particular the ortho-isomers.

The carrier polyol preferably has a hydroxyl value in the range of 40 to 250 mg KOH / g.

The solids content of the graft polyol is preferably in the range of from 30 to 55% by weight, based on the weight of the graft polyol.

As the olefinically unsaturated monomer, it is preferable to use a mixture of styrene and / or acrylonitrile, particularly preferably styrene and acrylonitrile. The acrylonitrile content of this mixture is particularly preferably in the range of from 30 to 80% by weight, based on the mixture.

The graft polyol (b1) preferably has a particle size of 0.1 to 8 占 퐉, preferably 0.2 to 4 占 퐉, and a maximum particle size of 0.2 to 3 占 퐉, preferably 0.2 to 2.0 占 퐉.

In a further preferred embodiment of the graft polyol (b1), the particle size distribution is bimodal, i.e. the distribution curve of the particle size has two maximum values. Such graft polyols can be prepared, for example, by mixing a graft polyol having a single-particle size distribution with an appropriate particle size, or by using a polyol that already contains a polymer of an olefinically unsaturated monomer as a carrier polyol in the initial charge of the reaction . In this embodiment, the particle size is also within the range described above.

In one embodiment of the invention, the graft polyol may be prepared continuously.

In a further preferred embodiment, the graft polyol is prepared by a semi-batch process.

With regard to the production of polyurethane foams, especially rigid foams, the following details may be provided.

Suitable organic polyisocyanates (a) are preferably aromatic polyfunctional polyisocyanates.

Specific examples are: tolylene 2,4- and 2,6-diisocyanate (TDI) and the corresponding isomer mixtures, diphenylmethane 4,4'-, 2,4'- and 2,2'-di Isocyanate (MDI) and corresponding isomer mixtures, mixtures of diphenylmethane 4,4'- and 2,4'-diisocyanate, polyphenylpolymethylene polyisocyanates, diphenylmethane 4,4'-, 2,4'- And a mixture of 2,2'-diisocyanate and polyphenyl polymethylene polyisocyanate (crude MDI) and a mixture of crude MDI and tolylene diisocyanate. Organic diisocyanates and polyisocyanates can be used individually or in the form of mixtures.

Modified multifunctional isocyanates, i.e., products obtained by chemical reaction of organic diisocyanates and / or polyisocyanates are also frequently used. Examples which may be mentioned are diisocyanates and / or polyisocyanates comprising isocyanurate and / or urethane groups. The modified polyisocyanates can be used in combination with each other or with unmodified organic polyisocyanates such as diphenylmethane 2,4'-, 4,4'-diisocyanate, crude MDI, tolylene 2,4- and / or 2,6- Can be optionally mixed with a diisocyanate.

Additionally, a reaction product of a polyfunctional isocyanate and a polyhydric polyol and also a mixture of this and other diisocyanates and polyisocyanates can also be used.

It has been found that crude MDI having an NCO content of 29 to 33 wt.% And a viscosity in the range of 150 to 1000 mPa s at 25 DEG C is particularly useful as an organic polyisocyanate.

The particle-containing polyol (bi1) can be used singly as compound (b) containing at least two hydrogen atoms, which are generally reactive with isocyanate groups. However, this compound (b1) is preferably used in combination with other compounds having two or more hydrogen atoms that are reactive with the isocyanate group.

For this purpose, it is possible to use conventional and known compounds having at least two hydrogen atoms which are reactive towards isocyanate groups. It is preferable to use a polyether alcohol and / or a polyester alcohol in combination with the polyol (b1).

Polyester alcohols used with polyol (b1) are usually polyfunctional alcohols having usually 2 to 12 carbon atoms, preferably 2 to 6 carbon atoms, preferably diols and prod- ucts having 2 to 12 carbon atoms Soluble carboxylic acid such as succinic acid, glutaric acid, adipic acid, succinic acid, azelaic acid, sebacic acid, decanedicarboxylic acid, maleic acid, fumaric acid, preferably phthalic acid, isophthalic acid, terephthalic acid and isomeric naphthalene dicarboxylic acid . ≪ / RTI >

The polyether alcohols used with the polyol (b1) usually have a functionality ranging from 2 to 8, in particular from 3 to 8.

In particular, polyether alcohols prepared by anionic polymerization of alkylene oxides in the presence of catalysts, preferably alkali metal hydroxides, are used in known manner.

As the alkylene oxide, usually ethylene oxide and / or propylene oxide, preferably pure 1,2-propylene oxide, is used.

As the starting molecule, compounds having three or more, preferably four to eight, hydroxyl groups or two or more primary amino groups in the molecule are used.

As starting molecules having 3 or more, preferably 4 to 8, hydroxyl groups in the molecule, trimethylolpropane, glycerol, pentaerythritol, sugar compounds such as glucose, sorbitol, mannitol and sucrose, polyhydric phenols, Oligomer condensation products of phenol and formaldehyde, and Mannich condensation products of phenol, formaldehyde and dialkanolamine, and also melamine.

As starting molecules having two or more primary amino groups in the molecule, aromatic diamines and / or polyamines such as phenylenediamine, 2,3-, 2,4-, 3,4- and 2,6-toluenediamine ( TDA), especially 2,3- and 3,4-TDA, and 4,4'-, 2,4'- and 2,2'-diaminodiphenylmethane, and also aliphatic diamines and polyamines such as ethylenediamine Is preferably used. The 2,3- and 3,4-isomers of TDA are also referred to as vicinal TDA.

The polyether alcohols preferably have a functionality of from 3 to 8 and preferably from 100 mg KOH / g to 1200 mg KOH / g, in particular from 240 mg KOH / g to 570 mg KOH / g.

In a preferred embodiment of the process of the present invention, a mixture of at least one polyether alcohol (bii2) disclosed using a graft polyol (bi1) and an aliphatic amine is used as a compound having two or more hydrogen atoms that are reactive toward isocyanate groups . This polyether alcohol (bii2) preferably has a hydroxyl value in the range of 375 to 525 mg KOH / g.

In a further preferred embodiment of the process of the present invention, the mixture of at least one polyether alcohol (bii3) disclosed using a graft polyol (bi1) and an aromatic amine is a compound having two or more hydrogen atoms which are reactive towards isocyanate groups Is used. The polyether alcohol (bii3) preferably has a hydroxyl value in the range of 375 to 525 mg KOH / g. Furthermore, polyether alcohols, initiated using the neighboring TDA and having a hydroxyl value of 100 to 250 mg KOH / g, may be used as the polyol (bii3).

In a further preferred embodiment of the method of the invention, the mixture of the graft polyol (bi1) and one or more polyether alcohols (bii4) disclosed using sugars, in particular sorbitol or sucrose, contains two or more hydrogen atoms which are reactive towards isocyanate groups . ≪ / RTI > The polyether alcohol (bii4) preferably has a hydroxyl value in the range of 300 to 700 mg KOH / g.

In a further preferred embodiment of the process according to the invention, the mixture of the graft polyol (bi1) and one or more polyether alcohols (bii5) disclosed using trihydric alcohols, in particular glycerol and / or trimethylolpropane, Is used as a compound having two or more hydrogen atoms. The polyether alcohol (bii5) preferably has a hydroxyl value in the range of 100 to 250 mg KOH / g.

In a further preferred embodiment of the present invention, the polyol (bi) or (bii) comprises the polyether alcohol (bii6) disclosed using bifunctional alcohols.

In a further preferred embodiment of the present invention, compound (b) comprises at least one polyol (bii1), at least one polyol (bii4) and at least one polyol (bii2) and / or a polyol (bii3).

The preferred polyol component comprises polyol (bii1) in a proportion of 10 to 30 wt%, polyol (bii2) in a proportion of 0 to 15 wt%, polyol (bii3) in a proportion of 15 to 40 wt% In a proportion of 25 to 60% by weight and a polyol (bii5) in a proportion of 0 to 15% by weight.

The compound (b) having two or more hydrogen atoms reactive with the isocyanate group also includes a chain extender and a crosslinking agent which may be optionally used. Rigid polyurethane foams may be prepared with or without chain extenders and / or crosslinkers. The addition of bifunctional chain extender, trifunctional or higher functional crosslinker or any mixture thereof may be beneficial in modifying the mechanical properties. As chain extenders and / or crosslinkers, it is preferred to use alkanolamines, in particular diols and / or triols, having a molecular weight of less than 400, preferably 60 to 300.

Chain extenders, crosslinking agents or mixtures thereof are advantageously used in an amount of from 1 to 20% by weight, preferably from 2 to 5% by weight, based on the compound (b) having at least two hydrogen atoms which are reactive towards isocyanate groups do.

The reaction is usually carried out in the presence of catalysts, blowing agents and conventional auxiliaries and / or additives.

As the catalyst, a compound that strongly promotes the reaction between an isocyanate group and a group reactive with an isocyanate group is used.

Such catalysts are strongly basic amines such as secondary aliphatic amines, imidazoles, amidines and or alkanolamines or organometallic compounds, especially organotin compounds.

When isocyanurate groups are also incorporated into the rigid polyurethane foam, certain catalysts are needed for this purpose. As the isocyanurate catalyst, usually a metal carboxylate, especially potassium acetate and a solution thereof, is used.

The catalysts may be used alone or in any combination with one another, depending on the requirements.

As the foaming agent, it is preferable to remove carbon dioxide by using water reacting with the isocyanate group. It is also possible to use physical blowing agents in combination with water or in place of water. This compound is a compound that is inert to the starting material and is usually liquid at room temperature and vaporizes under the conditions of the urethane reaction. The boiling point of this compound is preferably 50 DEG C or lower. Physical blowing agents also include compounds that are gaseous at room temperature and are introduced into the starting material under superatmospheric pressure or dissolved therein, such as carbon dioxide, low boiling alkanes, and fluoroalkanes.

The compounds generally include alkanes and cycloalkanes having at least 4 carbon atoms, dialkyl ethers, esters, ketones, acetals, fluoroalkanes having 1 to 8 carbon atoms, and tetraalkyl having 1 to 3 carbon atoms in the alkyl chain Silane, especially tetramethylsilane.

Examples which may be mentioned are propane, n-butane, isobutane and cyclobutane, n-pentane, isopentane and cyclopentane, cyclohexane, dimethyl ether, methyl ethyl ether, methyl butyl ether, methyl formate, acetone and also in the troposphere Fluoroalkanes which can be decomposed and thus do not damage the ozone layer, such as trifluoromethane, difluoromethane, 1,1,1,3,3-pentafluorobutane, 1,1,1,3, 3-pentafluoropropane, 1,1,1,2-tetrafluoroethane, difluoroethane and 1,1,1,2,3,3,3-heptafluoropropane, and also perfluoroalkane Such as C ₃ F ₈ , C ₄ F ₁₀ , C ₅ F ₁₂ , C ₆ F ₁₄ or C ₇ F ₁₇ . The above-mentioned physical foaming agents may be used alone or in any combination with each other.

The foaming agent particularly preferably comprises one or more aliphatic hydrocarbons, preferably containing at least 4 carbon atoms. In a preferred embodiment of the process of the present invention, a combination of water and aliphatic hydrocarbons is used as blowing agent. Preferred hydrocarbons are n-pentane, isopentane and cyclopentane.

Particularly when hydrocarbons are used as foaming agents, optimal incorporation of particles into the bubble walls can occur.

The process of the present invention can be carried out, if necessary, in the presence of flame retardants and also conventional adjuvants and / or additives.

As the flame retardant, it is possible to use an organic phosphoric acid and / or a phosphonic acid ester. It is preferable to use a compound which is not reactive with an isocyanate group. Chlorine-containing phosphate esters are also one of the preferred compounds.

Typical representatives of this flame retardant group include triethyl phosphate, diphenylcresyl phosphate, tris (chloropropyl) phosphate and diethyl ethane phosphonate.

In addition, bromine containing flame retardants may also be used. As the bromine-containing flame retardant, it is preferable to use a compound having a group reactive with an isocyanate group. Such compounds include, for example, esters of tetrabromophthalic acid and aliphatic diols and alkoxylation products of dibromobutene diol. Compounds derived from the group of neopentyl bromide compounds containing OH groups can also be used.

As fillers, pigments, dyes, flame retardants, hydrolysis inhibitors, antifoggants, fungistatic agents and / or other additives known for this purpose, such as, for example, surface active agents, foam stabilizers, Use a bacteriostatic agent.

Further details of the starting materials, blowing agents, catalysts and adjuvants and / or additives used to carry out the process of the present invention can be found in, for example, Kunststoffhandbuch, Band 7, "Polyurethane" Carl-Hanser-Verlag, Munchen, Auflage, 1966, 2. Auflage, 1983 und 3. Auflage, 1993].

In order to prepare the rigid polyurethane foam, the polyisocyanate (a) and the compound (b) having two or more hydrogen atoms reactive with the isocyanate group are used in an amount such that the isocyanate index is in the range of 100 to 220, preferably 115 to 195 . Rigid polyurethane foams may be prepared batchwise or continuously using known mixing equipment.

The preparation of polyisocyanurate foams can also be performed at higher, preferably at or below 350 index.

The hard PUR foams of the present invention are usually prepared by a two-component process. In this process, the compound (b) having two or more hydrogen atoms reactive with the isocyanate group is mixed with the flame retardant, the catalyst (c), the blowing agent (d), and further additives and / or additives to provide a polyol component, The component reacts with a polyisocyanate, or a mixture of a polyisocyanate and any blowing agent, also referred to as an isocyanate component.

The starting components are usually mixed at a temperature of from 15 to 35 占 폚, preferably from 20 to 30 占 폚. The reaction mixture may be cast into a closed support tool using a high or low pressure gauge.

In addition, the reaction mixture can also be injected or freely sprayed onto the surface or into the open cavity. Roofs and complex vessels can be insulated in the system by this method. The reaction mixture can also be introduced at one point into the closed mold, which can also have complex geometry, or at multiple points simultaneously. The reaction mixture can be injected onto the mold at various points. The mold may have a three-dimensional spatially different arrangement at the time the reaction mixture is injected. The manufacture of refrigerated appliances is a common example of such a method. The reaction mixture can likewise be injected into an open mold which is closed after the mold is filled. This method is conventional, for example, in the manufacture of doors of refrigeration appliances.

Preparation of graft polyol

The graft polyols used in the following examples can be prepared by continuous processes and discontinuous processes. The synthesis of graft polyols by both processes is known. The synthesis of graft polyols by a semi-batch process is described, for example, in EP 439755. A particular form of the semi-batch process is a semi-batch seed process in which the graft polyol is further used as a seed in the initial charge of the reaction, for example as described in EP 510533. The synthesis of graft polyols having a bimodal particle size distribution is described in WO 03/078496. The synthesis of graft polyols by a continuous process is likewise known and is described, for example, in WO 00/59971.

Grafted polyols for Examples and Comparative Examples were prepared in a semi-batch process.

The preparation of graft polyols for the Examples and Comparative Examples by semi-batch process was carried out in a 2 liter autoclave equipped with a two-stage stirrer, an internal cooling coil and an electric heating mantle. Prior to the start of the reaction, the reactor was charged with a mixture of the carrier polyol and the superpowder itself, flushed with nitrogen and then heated to a synthesis temperature of 125 캜 or 130 캜. In some syntheses, a graft polyol in addition to the carrier polyol and the high molecular weight was further added as a seed to the initial charge of the reaction. In an additional group of experiments, only a portion of the bulk material itself was initially introduced into the reactor. The remaining amount was introduced into the reactor during synthesis via an independent feed stream.

The remainder of the reaction mixture comprising the additional carrier polyol, the initiator, the monomer and the reaction modifier was placed in two or more feed vessels. The synthesis of the graft polyol was carried out by delivering the raw material from the feed container via a static in-line mixer into the reactor at a constant feed rate. The introduction time of the monomer / modifier mixture was 150 minutes or 180 minutes while the polyol / initiator mixture was metered into the reactor over 165 minutes or 195 minutes. After a further reaction time of 10 to 30 minutes at the reaction temperature, the crude graft polyol was transferred into the glass flask via the bottom outlet. The product was subsequently separated from unreacted monomers and other volatile compounds at a temperature of 135 < 0 &gt; C under reduced pressure (<0.1 mbar). The final product was subsequently stabilized with an antioxidant.

A specific trowel itself was used for the graft polyol 5-7. This was a polyether siloxane corresponding to the formula:

Wherein x, y, z, n and m are numbers with the values given in the specification, R is an alkyl group having 1 to 10 carbon atoms and M is an alkyl group via an ether, ester, urethane or acetal group to a polyether chain Is a bivalent aliphatic, aromatic, or araliphatic group having from 2 to 10 carbon atoms, such as Tegostab B8462, which uses a molecular defect of TMI to react with dimethyl-m-isopropenyl benzylisocyanate (TMI ) To statistically allow not more than one OH group to react per molecule of polyether siloxane.

Production of rigid foam (mechanical foaming)

Various polyols, stabilizers, catalysts were mixed with water and blowing agent in the ratios shown in Table 1. 100 parts by weight of the polyol component was mixed with a mixture of diphenylmethane diisocyanate and polyphenylene polymethylene polyisocyanate having an NCO content of 31.5% by weight and a viscosity of 200 mPa 占 퐏 (25 占 폚) Were mixed in Puromat® HD 30 (Elastogran GmbH) high pressure blower. The reaction mixture was poured into a mold having dimensions of 200 cm x 20 cm x 5 cm or 40 cm x 70 cm x 9 cm and the foam was formed therein. The properties and characteristic data of the resulting foam are shown in Table 1.

The rigid polyurethane foams produced by the process of the present invention can be prepared with very short release times based on phase-stable polyol components which enable significantly shorter cycle times. Despite the presence of graft polyols, a large amount of physical blowing agent is soluble in the polyol component, allowing a foam density of less than 30 g / l of the component to be achieved. The foam properties for the compressive strength, thermal conductivity and quality of the foam surface (sinkhole formation) are very good.

The polyurethane reaction mixture was injected (10% overcharged) into a mold having dimensions of 200 x 20 x 5 cm &lt; ³ &gt; and after several hours, the specimens having dimensions of 20 x 20 x 2 cm &lt; ³ &gt;

The compressive strength was measured according to DIN 53421 / DIN EN ISO 604.

Particle ratios in the bubble walls were measured by quantitative evaluation of the scanning electron microscope photographs of the foam.

Measurement of Particle Ratio in Bubble Walls: Scanning Microscopy, Statistical Evaluation of Particles.

The present invention is illustrated by the following examples. All data are in parts by mass unless otherwise specified. The index and flow coefficient have no units.

Comparative Example 1 Comparative Example 2 Example 1 Example 2 Example 3 Polyol 1 25 25 25 25 25 Polyol 2 52 52 52 52 52 Polyol 3 16 13 13 13 13 Polyol 4 - 3 - - - Polyol 5 - - 3 - - Polyol 6 - - - 3 - Polyol 7 - - - - 3 Stabilizer 2 2 0.4 0.4 2 water 2.3 2.3 2.3 2.3 2.3 catalyst 1.8 1.8 1.8 1.8 1.8 Cyclopentane 9.8 9.8 9.8 9.8 9.8 Isopentane 4.2 4.2 4.2 4.2 4.2 Formic acid - 2.3 - 2.3 - index 117 117 117 117 117 Fiber Time [s] 43 40 37 40 38 Free Foam Density [g / l] 23.8 24.5 23.9 24.3 24.5 Minimum filling density [g / l] 31.9 32.1 29 31.6 31.8 Flow coefficient (minimum filling density / free foam density) 1.31 1.31 1.33 1.30 1.30 Percentage of continuous bubbles [%] 6 5 6 5 4 Thermal conductivity [MW / mK] 18.8 19.6 18.8 19.8 19.5 Compressive strength (FD 31) 20% overpack, [N / mm ² ] 0.16 0.16 0.2 0.21 0.2 24 hours, after additional occurrence, 4 minutes, 20% over pack [mm] 93.2 92.8 91.8 91.3 91.5 Percentage of filler in the bubble wall 0% 10% 60% 70% 60%

Polyol 1 - Neighboring TDA and polyether alcohols derived from ethylene oxide and propylene oxide (390 mg KOH / g of hydroxyl)

Polyol 2 - Polyether alcohol derived from sucrose, glycerol, and propylene oxide (440 mg KOH / g of hydroxyl)

Polyol 3 - Neighboring TDA and polyether alcohol derived from ethylene oxide and propylene oxide (160 mg KOH / g of hydroxyl)

Graft polyol (19 mg KOH / g of hydroxyl) prepared by in situ polymerization of styrene and acrylonitrile in polyether alcohol (35 mg KOH / g of hydroxyl) derived from polyol 4-glycerol and propylene oxide. The tincture itself is the reaction product of sorbitol with ethylene oxide / propylene oxide and TMI (molecular weight 18000 g / mole).

Polyol 5 - A graft polyol similar to polyol 4, prepared in the presence of a polyether siloxane surfactant, that is, a high molecular weight corresponding to the above-mentioned formula. The molecular weight of the siloxane chain in this compound is 4400 g / mole, 81% of ethylene oxide and 19% of propylene oxide are present in the side chain, and the molecular weight of this compound is 13000 g / mole.

Polyol 6-polyether siloxane A graft polyol analogous to polyol 4, prepared in the presence of a surfactant, i. E., A herb corresponding to the above-mentioned formula. The molecular weight of the siloxane chain in this compound is 5050 g / mol, 60% of ethylene oxide and 40% of propylene oxide are present in the side chain, and the molecular weight of this compound is 19000 g / mol.

Polyol 7 - Polyether siloxane A graft polyol, similar to polyol 4, prepared in the presence of a surfactant, i.e., a tall oil corresponding to the above-mentioned formula. The molecular weight of the siloxane chain in this compound is 5050 g / mol, 60% of ethylene oxide and 40% of propylene oxide are present in the side chain, and the molecular weight of this compound is 16000 g / mol.

The stabilizer is Tegostab B8462.

The catalyst is a mixture of N, N-dimethylcyclohexylamine, N, N, N ', N ", N'" -pentamethyldiethylenetriamine and Lupragen N600 (1,3,5-tris (Dimethylaminopropyl) -sym-hexahydrotriazine; S-triazine).

The foam according to the present invention has an increased compressive strength. Therefore, the foam density of the foam according to the present invention can be further reduced as compared with the conventional foam case.

Good cure in the surface area of the foam is an additional advantage. Even after a short release time, the foam is robust and less soft and less deformable than in the comparative dosage form. This offers advantages in the handling of freshly prepared foams.

Claims (17)

A particle-containing polyurethane foam, wherein the particles are mainly incorporated in a bubble wall, the particles being a polymer or an inorganic particle of an olefinically unsaturated monomer, the surface of the particle being modified by a surface active material, Form. The particulate polyurethane foam of claim 1, wherein the surface active material is a polyether siloxane having at least one side chain having at least one hydroxyl group. A process for producing a rigid polyurethane foam by reacting a polyisocyanate (a) with a compound (b) containing two or more hydrogen atoms reactive with an isocyanate group in the presence of a foaming agent (c) ) Comprises particles whose surface has been modified by a surface-active substance. The method of claim 3, wherein the polyether siloxane having at least one side chain having at least one hydroxyl group is used as a surfactant. The method according to claim 3 or 4, wherein the particles are present in component (b). 6. A composition according to any one of claims 3 to 5, wherein component (b) comprises at least one particle-containing polyether alcohol (bi) comprising at least two hydrogen atoms which are reactive towards isocyanate groups, the polyether alcohol Wherein the at least one monomer comprises an olefinically unsaturated bond and a surface active group, wherein the at least one monomer comprises an olefinically unsaturated bond and a surface active group. 7. A composition according to any one of claims 3 to 6, wherein component (b) comprises at least one particle-containing polyether alcohol (bi) comprising at least two hydrogen atoms which are reactive towards isocyanate groups, the polyether alcohol Wherein the graft particles are prepared and then modified by reaction with a surface active component. &Lt; Desc / Clms Page number 13 &gt; 8. A process according to any one of claims 3 to 7, wherein component (b) comprises at least one additional polyol (bii). 9. A process according to any one of claims 3 to 8, wherein the polyol (bi) or (bii) comprises the polyether alcohol (bii2) disclosed using an aromatic amine. 9. A process according to any one of claims 3 to 8, wherein the polyol (bi) or (bii) comprises the polyether alcohol (bii3) disclosed using an aromatic amine. 9. A process according to any one of claims 3 to 8, wherein the polyol (bi) or (bii) comprises the polyether alcohol (bii4) disclosed using sugars. 9. A process according to any one of claims 3 to 8, wherein the polyol (bi) or (bii) comprises the polyether alcohol (bii5) disclosed using a trifunctional alcohol. The process according to any one of claims 3 to 8, wherein the polyol (bi) or (bii) comprises the polyether alcohol (bii6) disclosed using a bifunctional alcohol. 14. The process according to any one of claims 3 to 13, wherein the compound (b) comprises at least one polyol (bii4) and at least one polyol (bi1) and / or (bi2). Containing polyether alcohols which can be prepared by in situ polymerization of olefinically unsaturated monomers in polyether alcohols, wherein at least one olefinically unsaturated monomer has surface-active properties. A process for preparing a particle-containing polyether alcohol by in-situ polymerization of olefinically unsaturated monomers in polyether alcohols, wherein the at least one olefinically unsaturated monomer has surface-active properties. A process for preparing a particle-containing polyether alcohol according to claim 15 by in situ polymerization of olefinically unsaturated monomers in polyether alcohols, wherein the preparation is carried out in a semi-batch process.