EP2091992A1

EP2091992A1 - Polyphenylenepolymethylene polyisocyanate and its use for producing polyurethane foams

Info

Publication number: EP2091992A1
Application number: EP07822476A
Authority: EP
Inventors: Hans-Jürgen Reese; Imbridt Murrar; Ralf Fritz; Andres Cabrera; Birgit Magg; Bärbel GUSCHEL
Original assignee: BASF SE
Current assignee: BASF SE
Priority date: 2006-11-17
Filing date: 2007-11-12
Publication date: 2009-08-26
Also published as: JP2010510339A; US20100076101A1; CN101563387A; CN101563387B; WO2008058920A1; KR20090091739A

Abstract

The invention relates to polyphenylenepolymethylene polyisocyanates (B) comprising (B1) the 2-ring product of polyphenylenepolymethylene polyisocyanate (B2) the 3-ring product of polyphenylenepolymethylene polyisocyanate (B3) the 4-ring product of polyphenylenepolymethylene polyisocyanate (B4) the 5-ring product of polyphenylenepolymethylene polyisocyanate, wherein the constituents (B2), (B3) and (B4) are, at a content of (B1) up to 55% by weight, based on the weight of (B), present in a weight ratio of (B2) : (B3) : (B4) of 8 ± 4 : 3.5 ± 1.8 : 1.2 ± 0.9 and the component (B) comprises at least 85% by weight, based on the weight of the component (B), of the constituents (B1), (B2), (B3) and (B4).

Description

Polyphenylenepolymethylene polyisocyanate and its use for the production of polyurethane foams

The invention relates to a specially composed Polyphenylenpoly- methylene polyisocyanate (MDI), a process for its preparation and its use for the production of polyurethanes, in particular polyurethane foams.

Polyurethane foams have long been known and described many times. They can be used for many technical applications. They are usually prepared by reacting polyisocyanates with compounds having at least two isocyanate-reactive hydrogen atoms.

Two commonly used classes of polyurethane foams are rigid polyurethane foams and one-component foams, also referred to as aerosol foams.

The use of rigid polyurethane foams is mainly for heat insulation, for example in refrigerators, transport or buildings and for the production of components, in particular sandwich elements.

In the preparation of said polyurethanes are used as polyisocyanates usually aromatic polyisocyanates, in particular MDI and its higher homologues used.

One-component foams made from aerosol containers are frequently used in the field of construction for the installation of windows and doors in buildings as well as filling material for building-related cavities or wall openings for pipe installations. Such an aerosol container includes a prepolymer as well as propellants and additives. By discharging its contents by means of blowing agent, its foaming by Frothwirkung and by its curing with atmospheric moisture, the desired foam. One-component foams based on NCO-containing prepolymers are the most well-known foams of this type. There are different products which, depending on the composition, lead to hard to soft elastic foams.

An essential requirement for the polyurethane foams is the dimensional stability. Dimensional stability means that the foam does not change its volume after curing, in particular does not shrink. With rigid foams, shrinkage can cause voids in the foam as well as detachment from the cover layers. With one-component foams for window and door installation, the shrinkage can lead to inadequate stability of the installed doors and windows.

The problem of dimensional stability in particular of one-component foams is technically not completely solved, so that in the qualities known to shrink to 5% for room temperature applications and shrinkage to 10% at 40 ⁰ C and 90% relative humidity in tropical applications as Technically induced shrinkage values are still permissible.

In the case of the two-component foams, in particular in the case of rigid foams, the shrinkage problem exists, in particular in the case of large molded parts, for the solution of which there is no indication.

Furthermore, increasingly foams are required on the market, which have a light color. The hitherto offered foams, which were prepared using the polyphenylene polymethylene polyisocyanates commonly used, are mostly colored brown. This can be particularly annoying for applications where the foam is visible.

The object of the invention was therefore to provide polyurethane foams which have good processing properties and performance properties, in particular good dimensional stability. Furthermore, the demands of the market for bright foams should be met. According to the process, foams for various fields of application, in particular one-component assembly foams and rigid polyurethane foams, should be producible.

The object could surprisingly be achieved by the use of a mixture of diphenylmethane diisocyanates and Polyphenylenpolymethylenpolyisocy- anaten with a special composition as an isocyanate component in the production of the foams.

The invention accordingly provides a polyphenylene polymethylene polyisocyanate

(B) containing

(B1) the 2-core product of polyphenylene polymethylene polyisocyanate

(B2) the 3-core product of the polyphenylene polymethylene polyisocyanate

(B3) the 4-core product of the polyphenylene polymethylene polyisocyanate

(B4) the 5-core product of the polyphenylene polymethylene polyisocyanate, wherein the components (B2), (B3) and (B4) at a content of (B1) of up to 55% by weight, based on the weight of (B), in the weight ratio (B2): (B3): ( B4) of 8 ± 4: 3.5 ± 1, 8: 1, 2 ± 0.9 and component (B) at least 85 wt .-%, based on the weight of component (B), the constituents (B1 ), (B2), (B3) and (B4).

The invention further provides a process for preparing polyurethane foams by reacting (A) compounds having at least two isocyanate-reactive hydrogen atoms, hereinafter also referred to as polyol component, with (B) polyisocyanates, characterized in that as polyisocyanate ( B) the polyphenylenepolymethylene polyisocyanate according to the invention is used.

The invention furthermore relates to a process for preparing the polyphenylene polymethylene polyisocyanate according to the invention, comprising the steps

a) preparation of polyphenylenepolymethylene polyisocyanate by reaction of polyphenylenepolymethylenepolyamine with phosgene,

b) removal of by-products from the polyphenylenepolymethylene polyisocyanate from step a).

The polyphenylenepolymethylene polyisocyanate according to the invention has, in addition to components (B1) to (B4), further constituents. Thus, the polyphenylenepolymethylene polyisocyanate (B) according to the invention also contains polyphenylenepolymethylene polyisocyanates with 6 or more cores. The term "nucleus" is understood here to mean an aromatic ring, and the compounds containing more than two aromatic nuclei may also be referred to as higher homologs in the following.

The polyphenylenepolymethylene polyisocyanate (B) according to the invention may further comprise other compounds containing isocyanate groups, such as reaction products of isocyanates with one another, in particular uretonimines, and / or polyphenylenepolymethylene polyisocyanates having 6 or more cores.

The proportion of such further constituents of component (B) is preferably at most 15% by weight, based on the weight of component (B).

The polyphenylenepolymethylene polyisocyanate (B) preferably contains not more than 1% by weight, more preferably not more than 6% by weight and in particular not more than 3% by weight, based on the weight of (B), of uretonimines. These belong to the 15% by weight, based on the weight of (B), of the other compounds. The determination of the contents of Polyphenylenpolymethylenpolyisocyanaten with different core contents is usually carried out by gas chromatography. The content of uretonimines in polyphenylenepolymethylene polyisocyanate is determined by FT-IR analysis on the basis of a calibration with 3-core uretonimine (test method PFO / A 00 / 22-03).

The polyphenylenepolymethylene polyisocyanate according to the invention preferably has a content of free NCO end groups of from 31.0 to 33.3% by weight.

The polyphenylenepolymethylene polyisocyanate (B) according to the invention, which has been obtained by means of extraction, preferably has an iodine color number of less than 5 iodine, an L ^* value of greater than 96 and a b ^* value of less than 15, determined in accordance with DIN 6162 and DIN 6164 ,

The polyphenylene polymethylene polyisocyanates according to the invention can be prepared by the usual methods. These are well known and include the preparation of diphenylmethanediamine (MDA) and its higher homologues by acid-catalyzed reaction of aniline and formaldehyde, neutralization and workup of the amine mixture thus obtained, its reaction with phosgene to polyphenylenpolymethylenpolyisocyanat and purification, work-up and optionally partial separation of the 2-core MDI. It has surprisingly been found that damage to the Polyphenylenpolymethylenpolyisocyanats by the formation of by-products occurs in particular by the temperature load in the workup of Polyphe- nylenpolymethylenpolyisocyanats and the distillative separation of the 2-core products. These disadvantages can be avoided if the temperature load occurs as briefly as possible, for example, if a smaller part of the 2-core MDI is separated. Furthermore, it is important that the temperature in the process is not increased to values above 220 ⁰ C. The polyphenylenepolymethylene polyisocyanate (B) according to the invention prepared in this way preferably has an iodine color number of less than 10 iodine, an L ^* value of greater than 89 and a b ^* value of less than 30, determined in accordance with DIN 6162 and DIN 6164.

The polyphenylenepolymethylene polyisocyanates according to the invention are prepared in a preferred process by first reacting polyphenylenepolymethylenepolyamine with phosgene in a process step a) in a conventional manner and liberating it in a subsequent process step b) from by-products, for example uretonimines. In principle, alternative procedures are possible if they lead to the same products.

The process step a) is well known and comprises, as described above, the acid-catalyzed reaction of aniline with formaldehyde, neutralization and workup of the resulting polyamine, its reaction with phosgene to the corresponding polyisocyanate, its work-up and purification. As described, the polyphenylenepolymethylene polyisocyanate according to the invention in step b) is freed from secondary compounds, such as uretonimine. These are formed during the production and work-up, in particular by thermal loading of the polyisocyanates. These secondary compounds from the production process, such as uretdiones, uretonimines, carbamoyl chlorides, are contained in the starting polyisocyanate to a maximum of 25 wt .-%. The removal is preferably carried out by liquid-liquid extraction with polar or non-polar solvents. In a particular embodiment, preferred solvents are hydrocarbons, such as cyclohexane. Such processes are described, for example, in DE 1, 543,258 or EP 133,538.

In a preferred embodiment of step b), the polyphenylene lenpolymethylenpolyisocyanat used with cyclohexane in the ratio of isocyanate: solvent of 1: 1 to 1: 15, preferably 1: 1, 5 to 1: 12 and more preferably 1: 2.5 to 1: 10 at a temperature of 20 to 90 ⁰ C and preferably 30 to 80 ⁰ C for 1 to 180 minutes, and preferably for 5 to 150 min in contact. Thereafter, the product mixture is allowed to stand until complete phase formation at 20 to 40 ⁰ C and preferably at room temperature. The lower phase is the so-called "raffinate" containing the uretonimine to be separated as well as higher nuclear MDI homologs. The upper phase is the so-called "extract" which contains the desired low-urethane polyphenylene polymethylene polyisocyanate and solvent. Both phases are separated and the solvent is almost completely removed, for example by means of vacuum distillation. The residual content of cyclohexane is preferably less than 20 ppm.

The polyphenylenepolymethylene polyisocyanate (B) according to the invention, which has been obtained by means of extraction, preferably has an iodine color number of less than 5 iodine, an L ^* value of greater than 96 and a b ^* value of less than 15, determined in accordance with DIN 6162 and DIN 6164.

Particularly good results are achieved if, during the production, the thermal load of the polyphenylene polymethylene polyisocyanate is kept low and, in addition, an extraction of the polyphenylene polymethylene polyisocyanate is carried out.

It is also possible to subject polyphenylene polymethylene polyisocyanate batches which do not have the composition according to the invention to extraction. The content of secondary compounds of more than 15% by weight can be reduced to the content according to the invention. It is also possible in this way to shift the core distribution in the direction of low-nuclear products. The extraction of the polyphenylenepolymethylene polyisocyanate can also be carried out following the partial separation of 2-core MDI, since in this case there is frequently an increase in the content of secondary compounds. In this case, the polyphenylenepolymethylene polyisocyanate (B) according to the invention, which was obtained by the process characteristics described above in polyphenylenepolymethylene polyisocyanate preparation, preferably has a content of 2-core product (B1) of from 20 to 50% by weight, based on the weight of (B), wherein components (B2), (B3) and (B4) are in the weight ratio (B2): (B3): (B4) of 8 ± 4: 3.5 ± 1, 8: 1, 2 ± 0.9 and component (B) contains at least 85% by weight, based on the weight of component (B), of components (B1), (B2), (B3) and (B4).

When the polyphenylenepolymethylene polyisocyanate (B) according to the invention has been obtained by extraction, it preferably has a content of 2-core product (B1) of from 20 to 55% by weight, based on the weight of (B), where the constituents ( B2), (B3) and (B4) in the weight ratio (B2) :( B3) :( B4) of 8 ± 4: 3.5 ± 1, 8: 1, 2 ± 0.9, and the component (B) at least 85% by weight, based on the weight of component (B), of components (B1), (B2), (B3) and (B4).

When the polyphenylene polymethylene polyisocyanate (B) of the present invention is obtained by partial removal of the 2-core MDI and subsequent extraction, it preferably has a content of 2-core product (B1) of 2 to 20% by weight, based on the weight of ( B), wherein the components (B2), (B3) and (B4) in the weight ratio (B2) :( B3) :( B4) of 8 ± 4: 3.5 ± 1, 8: 1, 2 ± 0.9 and component (B) contains at least 85% by weight, based on the weight of component (B), of components (B1), (B2), (B3) and (B4).

As described, the polyphenylenepolymethylene polyisocyanate according to the invention can be used for the production of polyurethane foams. Preferred applications here are 1-component polyurethane foams and rigid polyurethane foams. For this purpose, the polyphenylenepolymethylene polyisocyanate (B) according to the invention is reacted with compounds having at least two isocyanate-reactive hydrogen atoms (A).

In the preparation of the 1-component polyurethane foams, the reaction of the isocyanate component (B) with the compounds having at least two isocyanate-reactive hydrogen atoms (A) takes place in the presence of a blowing agent in a pressure vessel, preferably in an aerosol can. For this purpose, the polyol component (A) and the isocyanate component (B) are charged in the abovementioned ratio together with a blowing agent into a pressure vessel so that the prepolymer according to the invention with a lower content of free isocyanate groups is formed in the pressure vessel. Typical blowing agents for preparing the 1-component mounting foams are, for example, R134a (tetrafluoroethane), R152a (1,1-difluoroethane), dimethyl ether, propane, n-butane, isobutane, preferably mixtures of propane, n-butane and isobutane , The NCO content of the prepolymers in the aerosol can is preferably in the range of about 5 to 28 wt .-%, preferably 8 to 24 wt .-%, particularly preferably 9 to 18 wt .-%. Prepolymers with a lower NCO content lead to softer aerosol foams, those having a higher NCO content corresponding to harder foams.

For application of the 1-component polyurethane foams, the pressure vessel is expanded. In this case, the exiting prepolymer is foamed by the Froth effect of the propellant and hardens by the humidity.

It is necessary for many applications of the 1-component polyurethane foams to add additive flame retardants which also have a viscosity lowering effect. This need only be added in such an amount as is necessary to achieve the fire class of the finished foam.

Trialkylphosphates and trichloroalkylphosphates are mostly used as additive flame retardants. The alkyl radicals preferably have 1 to 4, more preferably 1 to 3 carbon atoms. Particularly preferred compounds are trimethyl phosphate, triethyl phosphate, tripropyl phosphate, trichloromethyl phosphate, trichloroethyl phosphate and trichloropropyl phosphate. These can be used individually or in any mixtures with each other.

The amount of additive flame retardant depends on the requirements of the foam. For the formulation of flame-retardant one-component polyurethane foams, the canned NCO prepolymer must be present in the

Sum a content of additive flame retardants of about 8 to 18 wt .-%, preferably 12 to 16 wt .-%, based on the weight of the prepolymer, have. At lower levels of flame retardancy may not be sufficient, too high levels of additive flame retardants of the foam is flowing, that is, he is not vertically applied, or the flame retardant migrated too much from the foam.

In the production of the rigid foams according to the invention, as is generally known, an isocyanate component, in the present process the polyphenylenepolymethylene polyisocyanate (B) according to the invention being used, with the compounds having at least two isocyanate-reactive hydrogen atoms (A) in the presence of catalysts and blowing agents Implementation brought.

As the blowing agent, water can be used which reacts with isocyanate groups with the cleavage of carbon dioxide. In combination with or instead of water, so-called physical blowing agents can also be used. These are compounds which are inert to the starting components and which are usually liquid at room temperature and evaporate under the conditions of the urethane reaction. fen. The boiling point of these compounds is preferably below 50 ^° C. The physical blowing agents also include compounds which are gaseous at room temperature and are introduced under pressure into or dissolved in the starting components, for example carbon dioxide, low-boiling alkanes and fluoroalkanes.

The compounds are for the most part selected from the group comprising alkanes and / or cycloalkanes having at least 4 carbon atoms, dialkyl ethers, esters, ketones, acetals,

Fluoroalkanes having 1 to 8 carbon atoms, and tetraalkylsilanes having 1 to 3 carbon atoms in the alkyl chain, in particular tetramethylsilane.

Examples which may be mentioned are propane, n-butane, iso- and cyclobutane, n-, iso- and cyclopentane, cyclohexane, dimethyl ether, methyl ethyl ether, methyl butyl ether, methyl formate, acetone, and fluoroalkanes, which can be degraded in the troposphere and therefore for the ozone layer are harmless, such as trifluoromethane, difluoromethane, 1, 1, 1, 3,3-pentafluorobutane, 1,1,1,3,3-pentafluoropropane, 1,1,1,2-tetrafluoroethane, difluoroethane and heptafluoropropane. Particular preference is given to using cyclopentane and / or n-pentane. The said physical blowing agents can be used alone or in any combination with each other.

To prepare the rigid polyurethane foams, the polyol component (A) and the polyisocyanates (B) are reacted in amounts such that the isocyanate index is in a range between 100 and 220, preferably between 125 and 195.

The rigid polyurethane foams can be prepared batchwise or continuously by means of known mixing devices.

The rigid polyurethane foams according to the invention are usually prepared by the two-component process. In this process, the compounds are mixed with at least two isocyanate-reactive hydrogen atoms (A), with the flame retardants, the blowing agents, the catalysts and other auxiliaries and / or additives to the so-called polyol and these with the polyisocyanates or mixtures of the polyisocyanates and, if appropriate, flame retardants and blowing agents, also referred to as the isocyanate component, for the reaction.

The starting components are usually mixed at a temperature of 15 to 35 ⁰ C, preferably from 20 to 30 ⁰ C. The reaction mixture can be poured into closed support tools with high or low pressure metering machines. According to this technology z. B. manufactured discontinuous sandwich panels. Surprisingly, the foams produced by the process according to the invention have a very light, sometimes even white color. The foams are dimensionally stable and can be applied very well.

The following can be said in detail about the other polyols for the preparation of the polyurethane foams according to the invention:

Suitable compounds having at least two isocyanate-reactive hydrogen atoms (A) which can be used for the process according to the invention are in particular polyether alcohols and / or polyester alcohols in the production of the rigid foams and in the preparation of the prepolymers for the 1-component structural foams OH numbers in the range of 100 to 1200 mgKOH / g are used.

The polyester alcohols used are usually obtained by condensation of polyfunctional alcohols, preferably diols, having 2 to 12 carbon atoms, preferably 2 to 6 carbon atoms, with polyfunctional carboxylic acids having 2 to 12 carbon atoms, for example succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid, Decanedicarboxylic acid, maleic acid, fumaric acid and preferably phthalic acid, isophthalic acid, terephthalic acid and the isomeric naphthalenedicarboxylic acids.

The polyether alcohols used usually have a functionality between 2 and 8, in particular 3 to 8.

In particular, polyether polyols which are prepared by known processes, for example by anionic polymerization of alkylene oxides in the presence of catalysts, preferably alkali metal hydroxides, are used.

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

In particular, compounds having at least 3, preferably 4 to 8 hydroxyl groups or having at least two primary amino groups in the molecule are used as starting molecules.

As starting molecules having at least 3, preferably 4 to 8 hydroxyl groups in the molecule are preferably trimethylolpropane, glycerol, pentaerythritol, sugar compounds such as glucose, sorbitol, mannitol and sucrose, polyhydric phenols, resoles such as oligomeric condensation products of phenol and formaldehyde and Mannich condensates from phenols, formaldehyde and dialkanolamines and melamine used. As starting molecules having at least two primary amino groups in the molecule are preferably aromatic di- and / or polyamines, for example phenylenediamines, 2,3-, 2,4-, 3,4- and 2,6-toluenediamine and 4,4'-, 2 , 4'- and 2,2'-diamino-diphenyl methane and aliphatic di- and polyamines, such as ethylenediamine used.

The polyether polyols have a functionality of preferably 3 to 8 and hydroxyl numbers of preferably 100 mgKOH / g to 1200 mgKOH / g and especially 240 mgKOH / g to 570 mgKOH / g. In addition, it is also possible to use polyols, in particular polyether alcohols having a hydroxyl number of less than 100 mg KOH / g and a functionality of from 2 to 3. As a result, the properties of the foams can be adjusted, for example in the case of 1-component assembly foams, in the direction of greater flexibility.

The compounds having at least two isocyanate-reactive hydrogen atoms (A) also include the optionally used chain extenders and crosslinkers. To modify the mechanical properties, the addition of difunctional chain extenders, trifunctional and higher functional crosslinking agents or optionally also mixtures thereof may prove to be advantageous. As chain extenders and / or crosslinking agents are preferably used alkanolamines and in particular diols and / or triols having molecular weights less than 400, preferably 60 to 300.

Chain extenders, crosslinking agents or mixtures thereof are expediently used in an amount of from 1 to 20% by weight, preferably from 2 to 5% by weight, based on the polyol component (A).

In addition to the polyester and polyether polyols mentioned, chain extenders and crosslinkers monoolers can in the field of 1-component polyurethane foams for the production of the required polyol component (A) as further OH-functional compounds as a targeted agent for molecular weight control, to form a permeable foam skin and finally Storage stability improvement can be used. These monools having molecular weights of up to 1400 g / mol (OH number about 40 mgKOH / g) are usually used, if necessary, in proportions of up to 10% by weight, based on the polyol component (A).

Further information on the polyether alcohols and polyester alcohols used and their preparation can be found, for example, in Kunststoffhandbuch, Volume 7 "Polyurethane", edited by Günter Oertel, Carl-Hanser-Verlag Munich, 3rd edition, 1993. In a particularly preferred embodiment of the preparation of 1-component polyurethane foams, the polyol component (A) is a mixture of

(A1) a polyester polyol having a molecular weight of at most 600 g / mol and

(A2) a polyether polyol or polyether polyol mixture having an average molecular weight of 1000 to 5000 g / mol.

As the polyester polyol (A1), a polyester polyol based on phthalic anhydride / diethylene glycol / polyethylene glycol is preferably used.

The polyols (A1) and (A2) are preferably used in a weight ratio of polyester polyol (A1) to polyether polyol or polyether polyol mixture (A2) in the range from 1: 6 to 3: 1.

The catalysts used are in particular compounds which greatly accelerate the reaction of the isocyanate groups with the groups reactive with isocyanate groups. Such catalysts are strongly basic amines, such as. As secondary aliphatic amines, imidazoles, amidines, and alkanolamines.

If isocyanurate groups are to be incorporated into the rigid foam, special catalysts are required. The isocyanurate catalysts used are usually metal carboxylates, in particular potassium acetate and its solutions. In the production of such foams, also referred to as polyurethane-polyisocyanurate foams, the reaction of components (A) and (B) is usually carried out at an index of 160 to 450

The invention will be explained in more detail in the following exemplary embodiments.

Embodiment 1 - (One Component Foam)

1.1 Preparation of the polyol component:

From 300 g of a polyesterpolyol based on phthalic anhydride / diethylene glycol /

Polyethylene glycol having a molecular weight of 470 g / mol, 208 g of a polyether polyol based on glycerol / propylene oxide / ethylene oxide having a molecular weight of 4000 g / mol,

30 g of a polyether polyol based on sucrose / pentanediol / diethylene glycol having an average molecular weight of 540 g / mol, 40 g of a polyethylene glycol with a Molecular weight of 600 g / mol, 59 g of a monofunctional methylated polyethylene glycol having a molecular weight of 500 g / mol, 25 g of a foam stabilizer, 330 g

5 Trichloropropyl phosphate, 8 g of dimorpholinodiethyl ether, 0.5 g of silicone oil was prepared by Vermi see a polyol component.

1.2 Preparation of Isocyanate Preparations: 0

Polyphenylene polymethylene polyisocyanate (trade name: Lupranat ^® M20), having a monomeric MDI content of 37%, an NCO content of 31, 2 wt .-%, a viscosity of 213 mPa-s at 25 ⁰ C, a color number of 20 Iodine an L ^* value of 85.6, a b ^* value of 70.1 and a uretonimine content of 8.4 wt% was extracted in a one-step extraction process as described below with cyclohexane.

Polyphenylenepolymethylene was cyanate with cyclohexane in the ratio of iso-: solvent of 1: 3 at 50 ⁰ C for 60 min contacted. Thereafter, the product mixture was allowed to stand at room temperature until complete phase formation.

The upper phase was the so-called "extract" containing the desired polyphenylene polymethylene polyisocyanate and solvent. The solvent was removed from the

Extract completely removed by vacuum distillation (residual content of cyclohexane less than 20 ppm). 0 A product was obtained which can be characterized as follows:

Viscosity: 50 mPas (25 ° C)

NCO content: 32.6% by weight

Content of monomers (B1): 49.1% by weight 5 Uretonimine content: 1.6% by weight

Color number: 0.8 iodine

L ^* value: 99.3 b ^* value: 5.1 0

Content and ratio of higher homologues of diphenylmethane diisocyanate: (B2) 3-core product of polyphenylene polymethylene polyisocyanate 30.4 wt% (B3) 4-core product of polyphenylene polymethylene polyisocyanate 1.1, 4 wt% (B4) 5 Core product of polyphenylene polymethylene polyisocyanate 4.2% by weight from which a ratio of the components (B1): (B2): (B3) = 7.2: 2.7: 1 resulted.

The product prepared as described above was used in this form as an isocyanate component for the subsequent 1-component assembly foam production.

1.3 Preparation of the bright dimensionally stable 1-component mounting foam

268 g of the polyol component of embodiment 1.1 were filled into a 1 liter aerosol can. After addition of 361 g of Isocyanatzubereitung according to Embodiment Example 1.2, the aerosol can with a tilting valve, by means of a laboratory equipment for aerosol cans suitable apparatus, sealed.

56 g of dimethyl ether, 38 g of a propane / butane mixture of 20% by weight of propane and 80% by weight of butane and 94 g of tetrafluoromethane (R134a) were subsequently metered through the valve and the contents were homogenized by shaking. By heat storage of the aerosol can thus manufactured at 50 ⁰ C, an artificial aging was achieved, so that the manufactured aerosol can already after 24h storage and cooling to room temperature could be tested.

For this purpose, a laid on a flat surface paper fleece was moistened and discharged the contents of the aerosol can by pressing the tilt valve with screwed foam tube as a foaming mixture.

The discharge was carried out in foam strands, whereby a wetting of the foam surface with water took place between the foam strands discharged in layer form.

The cured foam was tested for its properties (see Table 1.4).

1.4 Properties of the 1-component mounting foams

Dimensional Stability ^* Dimensional Stability was measured on specimens of two particleboard plus spacer bars with intervening and cured foam. After curing the foam and removing the spacer bars, the percent change in plate spacing was measured as a measure of dimensional stability.

Exemplary embodiment 2 - (two-component rigid polyurethane foam)

2.1 Preparation of the polyol component

From 377 g of Lupranol 3424 (polyether polyol based on sucrose, pentaerythritol, diethylene glycol and propylene oxide having an OH number of 403 mgKOH / g), 230 g of Lupranol 3423 (polyether polyol based on sucrose, glycerol and propylene oxide having an OH number of 490 mgKOH / g), 20 g glycerine, 300 g Lupranol 1 100 (polyether polyol based on propylene glycol and propylene oxide with an OH number of 104 mgKOH / g), 54 g Lupranol VP9319 (polyether polyol based on trimethylolpropane and propylene oxide with an OH number of 160 mg KOH / g), 10 g of stabilizer Tegostab B8443, 5 g of stabilizer Niax SiIi cone SR 393 and 4.5 g of water, a polyol mixture was prepared. This mixture was mixed both 34 g of a catalyst mixture (23.3% N, N-dimethylcyclohexylamine, 18.7% 1-methylimidazole, 28% tetramethylhexanediamine and 30% Lupranol 1200 [polyether polyol based on propylene glycol and propylene oxide having an OH number of 248 mg KOH / g]) as well as 50 g of an aqueous glycerol / glycol mixture (containing 9% gyzerin and 31% dipropylene glycol) were added and the polyol component made therefrom. 2.2 isocyanate component

The isocyanate component according to Embodiment 1.2 was used.

2.3 Processing of components into rigid polyurethane foam

The components according to embodiment 2.1 or 2.2 were mixed in the mixing ratio polyol: isocyanate = 100: 136 and after foaming and curing, a white foam was obtained. The foam had (free-foamed) the following properties:

Start time: 15 sec

Setting time: 48 sec

Climbing time: 85 sec

Density: 37, 2 kg / m ³

Compressive strength: 28.1 N / cm ²

2.4 Comparison of Dimensional Stability

Using a polyol component in the composition analog execution example 2.1 rigid foam sandwich panels are relatively analogous to the composition according to execution example 1.2 and the other using previously commercially available polyphenylene polymethylene polyisocyanate (trade name: Lupranat ^® M20) on the one hand by using an isocyanate component prepared and measure their shrinkage after curing.

- Information according to technical information on Elastopor H 1101/1/0

Claims

claims

1. Polyphenylenepolymethylene polyisocyanate (B) containing (B1) the 2-core product of the polyphenylene polymethylene polyisocyanate

(B2) (B2) the 3-core product of the polyphenylene polymethylene polyisocyanate

(B3) the 4-core product of the polyphenylene polymethylene polyisocyanate (B4) (B4) is the 5-core product of the polyphenylene polymethylene polyisocyanate, wherein the components (B2), (B3) and (B4) have a content of (B1) of up to 55% by weight, based on the weight of (B), in the weight ratio (B2): (B3) :( B4) of 8 ± 4: 3.5 ± 1, 8: 1, 2 ± 0.9; component (B) at least 85% by weight, based on the weight of component (B), of the constituents

(B1), (B2), (B3) and (B4).

2. Polyphenylenpolymethylenpolyisocyanate according to claim 1, characterized in that component (B) contains at least 2% by weight, based on the weight of (B), of the component (B1).

3. Polyphenylenpolymethylenpolyisocyanate according to claim 1, characterized in that the component (B) contains a maximum of 15 wt .-%, based on the weight of component (B), of Polyphenylenpolymethylenpolyisocyanat with at least 6 cores and other isocyanate-containing compounds.

4. Polyphenylenpolymethylenpolyisocyanate according to claim 3, characterized in that the other isocyanate-containing compounds containing uretoinimines.

5. Polyphenylenpolymethylenpolyisocyanate according to claim 3, characterized in that the other isocyanate group-containing compounds uretynimines in an amount of at most 11 wt .-%, based on the weight of Polyphenylenpolymethylenpolyisocyanats (B).

6. Polyphenylenpolymethylenpolyisocyanate according to claim 3, characterized in that the other isocyanate group-containing compounds uretynimines in an amount of not more than 6 wt .-%, based on the weight of Polyphenylenpolymethylenpolyisocyanats (B).

7. Polyphenylenpolymethylenpolyisocyanate according to claim 3, characterized in that the other isocyanate group-containing compounds uretynimines in an amount of not more than 3 wt .-%, based on the weight of polypyphenylenpolymethylenpolyiso- cyanate (B).

8. Polyphenylenpolymethylenpolyisocyanate according to claim 1, characterized in that the Polyphenylenpolymethylenpolyisocyanat has a content of free NCO end groups of 31, 0 to 33.3 wt .-%.

9. A process for the preparation of polyurethane foams by reacting (A) compounds having at least two isocyanate-reactive hydrogen atoms with (B) polyisocyanates, characterized in that as polyisocyanate (B) Polyphenylenpolymethylenpolyisocyanat is used according to claim 1.

10. The method according to claim 9, characterized in that the reaction in

Presence of blowing agents is performed.

1 1. A method according to claim 9, characterized in that the reaction is carried out in the presence of catalysts.

12. A process for the preparation of 1-component polyurethane foams by reacting (A) compounds having at least two isocyanate-reactive hydrogen atoms with (B) polyisocyanates by mixing the components (A) and (B) in a pressure vessel in the presence of blowing agents , characterized in that as polyisocyanate (B) polyphenylenepolymethylene polyisocyanate according to claim 1 is used.

13. The method according to claim 12, characterized in that in the reaction of components (A) and (B) component (B) is used in at least three times the stoichiometric excess.

14. A process for the production of rigid polyurethane foams by reacting (A) compounds having at least two isocyanate-reactive hydrogen atoms with (B) polyisocyanates in the presence of blowing agents, characterized in that as polyisocyanate (B) polyphenylenepolymethylene polyisocyanate according to claim 1 is used.

15. The method according to claim 14, characterized in that the reaction of the components (A) and (B) is carried out at an index of 100 to 220.

16. The method according to claim 14, characterized in that the reaction is carried out by the two-component method.

17. A process for the preparation of rigid polyurethane-polyisocyanurate foams by reacting (A) compounds having at least two isocyanate-reactive hydrogen atoms with (B) polyisocyanates in the presence of blowing agents and trimerization catalysts, characterized in that the polyisocyanate (B) Polyphenylenpolymethylenpolyisocyanat according to claim 1 is used.

18. The method according to claim 17, characterized in that the reaction of the components (A) and (B) is carried out at an index of 160 to 450.

19. A process for preparing polyphenylenepolymethylene polyisocyanate according to claim 1, comprising the steps of a) preparing polyphenylenepolymethylene polyisocyanate by reacting polyphenylenepolymethylenepolyamine with phosgene,

b) removal of by-products from the polyphenylene polymethylene polyisocyanate from step a).

20. The method according to claim 19, characterized in that step b) is an extraction.

21. A process for the preparation of Polyphenylenpolymethylenpolyisocyanat according to claim 1 by reacting Polyphenylenpolymethylenpolyamin with phosgene, characterized in that during the preparation and the workup of Polyphenylenpolymethylenpolyisocyanats a temperature of 220 ⁰ C is not exceeded.

22. Use of Polyphenylenpolymethylenpolyisocyanat according to claim 1 for the production of polyurethane foams.