HK1017001A - Rigid polyurethane foams - Google Patents

Description

Rigid polyurethane foams

The invention relates to a rigid polyurethane or urethane-modified polyisocyanurate foam and a preparation method thereof.

Rigid polyurethane or urethane-modified polyisocyanurate foams are generally prepared by reacting the appropriate polyisocyanate and isocyanate-reactive compound (usually a polyol) in the presence of a blowing agent. Such foams are insulating media for buildings, refrigerators and other household appliances.

The surface-active material, namely the foam stabilizer, is an important ingredient in the production of rigid polyurethane foams. They function to facilitate mixing of the ingredients, control cell size and stabilize the foam. These surfactants are often silicone based. The main disadvantage of this type of material is that it is too expensive. Thus, it is desirable to use formulations that do not contain silicone-based surfactants to prepare polyurethane foams.

WO 95/16721 describes particularly developed non-silicone polyether surfactants for use in the preparation of polyurethane foams.

The object of the present invention is to provide a rigid polyurethane foam which is prepared without using a silicone-based surfactant. It is another object of the present invention to prepare rigid polyurethane foams free of any silicone-based surfactant using ingredients well known in the art for preparing polyurethane foams.

The invention provides rigid polyamide and urethane-modified polyisocyanurate foams prepared by: reacting a polyisocyanurate composition with a polyfunctional isocyanate-reactive composition in the absence of silicone-based surfactant in the presence of a blowing agent, wherein the polyfunctional isocyanate-reactive composition comprises an amine-initiated polyether polyol as is well known in the art of producing rigid polyurethane foams.

Although the preparation is carried out in the absence of silicone-based surfactants, the foams of the present invention have a fine and uniform cell structure. Furthermore, the foams of the present invention have a better isotropic structure than prior art foams made in the presence of silicone-based surfactants, resulting in a stronger foam especially in the weakest direction (generally perpendicular to the rise direction for free rise foams) and a lower minimum stable density.

The amine-initiated polyether polyols useful in the present invention are the reaction products of alkylene oxides, such as ethylene oxide and/or propylene oxide, with amine initiators containing from 2 to 8 active hydrogens per molecule. Suitable initiators include ethylenediamine, ethanolamine, N-methylethanolamine, N-ethylethanolamine, diethanolamine, triethanolamine, triisopropanolamine, ammonia, toluenediamine, diaminodiphenylmethane, and polymethylene polyphenylene polyamines. Aromatic amine initiators are preferred, especially polymethylene polyphenylene polyamines. Another class of co-initiators may be used.

The total amount of amine-initiated polyether polyol is at least 20% by weight, preferably at least 30% by weight, most preferably from 40 to 80% by weight, based on the total amount of isocyanate-reactive compounds.

The polyfunctional isocyanate-reactive composition used in the present invention preferably also comprises polyethers well known in the art for the production of flexible polyurethane foams.

Such polyether polyols have an average nominal functionality of 2-6, preferably 2-4, and a number average molecular weight of 1000-10000. The OH numbers of such polyether polyols are generally from 20 to 80, preferably from 26 to 57, mgKOH/g.

These polyether polyols are obtained by polymerizing epoxides, such as ethylene oxide and propylene oxide, in the presence of polyfunctional initiators. Suitable initiators contain a plurality of active hydrogen atoms and include water and polyols such as ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, cyclohexanedimethanol, resorcinol, bisphenol A, glycerol, trimethylolpropane, 1, 2, 6-hexanetriol, pentaerythritol, sorbitol, and sucrose. Mixtures of initiators and/or epoxides may be used.

Particularly useful polyether polyols known in the art for the production of flexible polyurethane foams include polyoxypropylene diols and triols and poly (oxyethylene-oxypropylene) diols and triols (well described in the prior art) obtained by the simultaneous or sequential addition of ethylene oxide and propylene oxide to di-or trifunctional initiators. Mention may be made of random copolymers having an ethylene oxide content of from 10 to 80, block copolymers having an ethylene oxide content of not more than 25% and random/block copolymers having an ethylene oxide content of not more than 50%, all based on the total weight of the alkylene oxide units. Preferred diols and triols are ethylene glycol, diethylene glycol, dipropylene glycol and glycerol. Preferred polyether polyols are block copolymers having ethylene oxide blocks at the ends of the polyether. Such block copolymers are known as ethylene oxide capped polyols. These preferred ethylene oxide-capped polyols have an ethylene oxide content of at least 7 weight percent of the total oxyalkylene units.

The total amount of polyether polyol known in the art to be used for the production of flexible polyurethane foams is from 1 to 25% by weight, preferably from 1 to 15% by weight, most preferably from 1 to 10% by weight, based on the total amount of isocyanate-reactive components.

According to yet another embodiment of the present invention, the polyisocyanate composition used in the process of the present invention comprises the reaction product of a stoichiometric excess of an organic polyisocyanate and a substantially fluorinated isocyanate-reactive compound.

In the present context, the term "substantially fluorinated isocyanate-reactive compound" is understood to mean any organic compound having at least one isocyanate-reactive functional group and in which at least 50% of the hydrogen atoms bonded to the carbon atoms of the corresponding non-fluorinated compound are replaced by fluorine atoms.

Organic polyisocyanates and fully fluorinated isocyanate-reactive compounds for use in the process of the present invention are described in EP-A-0605105 (incorporated herein by reference).

Particularly preferred fully fluorinated isocyanate-reactive compounds are compounds of the following formula (I):wherein A is a substantially fluorinated or perfluorinated, linear or branched alkyl group containing 2 to 10 carbon atoms; n is an integer from 1 to 11; x is 0 or 1; r is hydrogen or C_1-12Alkyl or R '-OH, wherein R' is C_1-12An alkylene group.

Mention may in particular be made of the compounds of formula (I) defined below: n is 1 or 2, A is perfluoro C_3-10Preferably C_6-8Straight or branched alkyl, R is hydrogen or C_1-4Alkyl, R' is C_1-4An alkylene group; such as (perfluoropropyl) methanol, (perfluorobutyl) methanol, (perfluoropentyl) methanol, perfluoro (hexyl) methanol, (perfluoroheptyl) methanol, (perfluorooctyl) methanol, (perfluorononyl) methanol, (perfluoroethyl) ethanol, (perfluoropropyl) ethanol, (perfluorobutyl) ethanol, (perfluoropentyl) ethanol, (perfluorohexyl) ethanolAlcohols, (perfluoroheptyl) ethanol, (perfluorooctyl) ethanol, N-ethyl-N-2-hydroxyethylperfluorooctanesulfonamide, N-methyl-N-2-hydroxyethylperfluorooctanesulfonamide, N-propyl-N-2-hydroxyethylperfluorooctanesulfonamide, N-methyl-N-2-hydroxymethylperfluorooctanesulfonamide, N-propyl-N-2-hydroxymethylperfluorooctanesulfonamide, N-methyl-N-2-hydroxyethylperfluorooctanesulfonamide and di-N-2-hydroxyethylperfluorooctanesulfonamide.

Suitable organic polyisocyanates capable of reacting with the substantially fluorinated isocyanate-reactive compounds to produce reaction products useful in the process of the present invention include any of those known in the art for the preparation of rigid polyurethane or urethane-modified polyisocyanurate foams, in particular aromatic polyisocyanates such as diphenylmethane diisocyanate in the form of the 2, 4 ' -, 2, 2 ' -and 4, 4 ' -isomers and mixtures thereof, mixtures of diphenylmethane Diisocyanates (DMI) having an isocyanate functionality of greater than 2 and oligomers thereof, known in the art as "crude" or polymeric MDI (polymethylene polyphenylene polyisocyanates), toluene diisocyanate in the form of its 2, 4-and 2, 6-isomers and mixtures thereof, 1, 5-naphthalene diisocyanate and 1, 4-diisocyanatobenzene. Other polyisocyanates which may be mentioned include aliphatic diisocyanates such as isophorone diisocyanate, 1, 6-diisocyanatohexane and 4, 4' -diisocyanatodicyclohexylmethane.

The above-described polyisocyanate compositions useful in the process of the present invention may be conveniently prepared by adding a particular substantially fluorinated isocyanate-reactive compound to an organic polyisocyanate or by adding a plurality of different substantially fluorinated isocyanate-reactive compounds to an organic polyisocyanate, for example by reacting under conditions well known in the art for the preparation of isocyanate-terminated prepolymers. The amount of the fully fluorinated isocyanate-reactive compound added is preferably from 0.02 to 5% by weight, more preferably from 0.1 to 3% by weight, based on the organic polyisocyanate.

In order to increase the stability of the polyisocyanate compositions, it is advantageous to use allophanate variants of the obtained fluorinated isocyanate-terminated prepolymers. The allophanate variant can be prepared by reacting the resulting fluoroisocyanate-terminated prepolymer with the organic polyisocyanate itself in the presence of a suitable catalyst.

The polyisocyanate composition used in the process of the present invention may comprise only one type of said reaction product or may comprise different types of said reaction products derived from different substantially fluorinated isocyanate-reactive compounds and/or different polyisocyanates.

In a preferred embodiment of the present invention, the polyisocyanate composition comprises the reaction product of an organic polyisocyanate and the above-described fully fluorinated isocyanate-reactive composition comprising the above-described known polyether polyol used in the preparation of flexible polyurethane foams and the above-described known amine-initiated polyether polyol used in the manufacture of flexible polyurethane foams.

Rigid polyurethane foams prepared using such compositions also exhibit good thermal insulation properties.

Suitable organic polyisocyanates for use in the process of the present invention include any of those well known in the art for preparing rigid polyurethane or urethane-modified polyisocyanurate foams, particularly aromatic polyisocyanates such as diphenylmethane diisocyanate in the form of the 2, 4 ' -, 2, 2 ' -and 4, 4 ' -isomers and mixtures thereof, mixtures of diphenylmethane Diisocyanates (DMI) and oligomers thereof having an isocyanate functionality greater than 2, referred to in the art as "crude" or polymeric MDI (polymethylene polyphenylene polyisocyanates), toluene diisocyanates in the form of the 2, 4-and 2, 6-isomers and mixtures thereof, 1, 5-naphthalene diisocyanate and 1, 4-diisocyanatobenzene. Other polyisocyanates which may be mentioned include aliphatic diisocyanates such as isophorone diisocyanate, 1, 6-diisocyanatohexane and 4, 4' -diisocyanatodicyclohexylmethane. Other suitable polyisocyanates which can be used in the process of the present invention are those described in EP-A-0320134.

Other polyfunctional isocyanate-reactive compositions capable of reacting with the polyisocyanate composition to form the rigid polyurethane or urethane-modified polyisocyanurate foams of this invention include any of those well known in the art. Of particular importance for the preparation of rigid foams are polyols and polyol mixtures having an average hydroxyl number of 300-1000, in particular 300-700mgKOH/g, and a hydroxyl functionality of from 2 to 8, in particular from 3 to 8. Suitable polyols are well described in the prior art and include the reaction products of alkylene oxides, such as ethylene oxide and/or propylene oxide, with initiators containing from 2 to 8 active hydrogens per molecule. Suitable initiators include polyols such as glycerol, trimethylolpropane, triethanolamine, pentaerythritol, sorbitol and sucrose; and mixtures of such initiators. Other suitable polymer polyols include polyesters (particularly aromatic polyesters) obtained by the condensation of appropriate proportions of diols and higher functionality polyols with dicarboxylic or polycarboxylic acids. Suitable polymer polyols also include hydroxyl-terminated polythioethers, polyamides, polyesteramides, polycarbonates, polyacetals, polyolefins and polysiloxanes.

The amounts of polyisocyanate composition and polyfunctional isocyanate-reactive composition to be reacted will depend on the nature of the rigid polyurethane or urethane-modified polyisocyanurate foam to be produced and can readily be determined by the skilled person.

The process of the present invention is carried out in the presence of any blowing agent known in the art for the preparation of rigid polyurethane or urethane-modified polyisocyanurate foams. Such blowing agents include water or other compounds capable of evolving carbon dioxide, or inert or low boiling compounds having a boiling point above-70 ℃ at atmospheric pressure.

When water is used as blowing agent, the amount can be selected in a known manner to provide a foam of the desired density, typically in an amount of from 0.05 to 5% by weight based on the total amount of reaction system.

Suitable blowing agents include those known in the art and described above, such as hydrocarbon dialkyl ethers, alkyl alkyds, aliphatic and cycloaliphatic fluorocarbons, chlorofluorocarbons, chlorohydrocarbons, and fluoroethers.

Preferred blowing agents include n-pentane, isopentane, cyclopentane and mixtures thereof, 1, 1-dichloro-2-fluoroethane (HCFC 141b), 1, 1, 1-trifluoro-2-fluoroethane (HFC 134a), chlorodifluoromethane (HCFC 22), 1, 1-difluoro-3, 3, 3-trifluoropropane (HFC 245fa), 1, 1-difluoroethane (HFC 152a), 1, 1, 2, 3, 3-hexafluoropropane (HFC 236ea), 1, 1, 1, 4, 4, 4, -hexafluorobutane (HFC 356mfa), 1, 1, 1, 3, 3-pentafluorobutane (HFC 365mfc), difluoromethane (HFC 32) and mixtures thereof, including mixtures of hydrocarbons with chlorofluorocarbons and/or fluorocarbons. Mention may be made in particular of the blowing agent mixtures described in PCT patent publication No.96/12758 (incorporated herein by reference) for the production of low density, dimensionally stable rigid polyurethane foams. These blowing agent mixtures generally comprise at least 3, preferably at least 4, components, of which at least one is preferably a (cyclo) alkane (preferably having 5 or 6 carbon atoms) and/or acetone.

The total amount of blowing agent used in the reaction system for producing the cellular polymeric material is readily determined by the skilled person, but is generally from 2 to 25% by weight of the total reaction system.

The foams of the invention generally have a density of from 15 to 70 kg/m, preferably from 20 to 50 kg/m, most preferably from 25 to 40 kg/m.

In addition to the polyisocyanate and polyfunctional isocyanate-reactive compositions and blowing agents, the foam-forming reaction mixture will generally contain one or more other conventional adjuvants or additives in the formulation for the production of rigid polyurethane and urethane-modified polyisocyanurate foams. Optional additives to these include cross-linking such as low molecular weight polyols, e.g., triethanolamine, urethane catalysts such as tin compounds, e.g., tin octoate or dibutyltin dilaurate, or tertiary amines, e.g., dimethylcyclohexylamine or triethylenediamine, and flame retardants such as haloalkyl phosphates, e.g., trichloropropyl phosphate.

The foam-forming reaction mixture may also contain foam stabilizers or non-silicone based surfactants such as acetylenic surfactants, fluorinated surfactants (e.g., as described in US 5453540, US 5292716, US 5211873, US 5210106, US 5162385 and "organofluorine chemistry" (r. banks, b. smart, j. titlow) chapters 11, 14, 17, 20, 21, 22), chlorinated or propoxylated nonylphenols, ethoxylated or propoxylated C6-C26 monoalcohols, anionic or cationic surfactants or other surfactants as described in 'Handbook of surfactants' chapters 6-12 (1991, Porter). The addition of such surfactants can improve the thermal insulation properties of the foams of the present invention.

Another surfactant useful in the process of the present invention is an insoluble fluoro compound that can produce insoluble cells and can improve thermal insulation. The term "insoluble" as used herein in relation to "insoluble fluoro compounds" is defined as exhibiting solubility at concentrations below 500ppm at 25 ℃ and atmospheric pressure when mixed with an isocyanate reactive composition or a polyisocyanate composition. The insoluble fluoro compounds used in the process of the present invention include all those described in the following documents: us patent 4981879, us patent 5034424, us patent 4972002, european patent applications 0508649 and 0498628 and PCT patent application 95/18176.

Preference is given to using insoluble, substantially fluorinated or perfluorinated compounds having a boiling point of at least 20 ℃ (atmospheric pressure).

The term "substantially fluorinated" as used in the context of the insoluble, substantially fluorinated compound used in the process of the present invention should be understood to include compounds in which at least 50% of the hydrogen atoms of the non-fluorinated compound are replaced by fluorine.

Suitable compounds include fully fluorinated or perfluorinated hydrocarbons, fully fluorinated or perfluorinated ethers, fully fluorinated or perfluorinated tertiary amines, fully fluorinated or perfluorinated amino ethers, and fully fluorinated or perfluorinated sulfones.

Examples of suitable sufficiently fluorinated or perfluorinated hydrocarbons are those containing from 1 to 15 carbon atoms, which may be cyclic or acyclic, aromatic or aliphatic, saturated or unsaturated, such as sufficiently fluorinated and perfluorinated methane, ethane, propane, butane, pentane, hexane, heptane, octane, nonane, decane, cyclobutane, cyclooctane, cyclohexane, cyclopentane, cycloheptane, norbornadiene, decalin, dimethylcyclobutane, methylcyclohexane, 1-methyldecalin, phenanthrene, dimethylcyclobutane and mixtures thereof. Mention may in particular be made of the various isomers of perfluoropentane and perfluorohexane, such as the dimers and trimers of perfluoro-n-pentane and perfluorohexane and hexafluoropropylene, such as perfluoro (4-methylpent-2-ene).

Certain insoluble fluoro-compounds suitable for use in the process of the present invention may themselves function as blowing agents under foam forming conditions, particularly where the boiling point is lower than the exothermic temperature reached by the reaction mixture. For the avoidance of doubt, the compound may be made to function partially or fully as a blowing agent in addition to the insoluble fluoro compound.

In the process of the present invention, the insoluble fluoro compound is used in an amount of 0.05 to 10%, preferably 0.1 to 5%, most preferably 0.6 to 2.3% by weight of the total foam-forming composition.

The insoluble fluoro compound is incorporated in the foam-forming reaction mixture in the form of an emulsion or preferably a microemulsion in the main component, that is to say in the isocyanate-reactive component and/or the polyisocyanate component. Such emulsions or microemulsions may be prepared by conventional techniques and with suitable emulsifiers such as fluorosurfactants.

In the process of the present invention for the manufacture of rigid foams, rigid foams in the form of slabs, moldings, cavity fillings, spray foams, foam foams or laminates with other materials, such as rigid panels, rubber panels, plastics, paper or metal, can be produced using known one-shot, prepolymer or semi-prepolymer techniques and conventional mixing methods.

Various aspects of the present invention are illustrated, but not limited, by the following examples in which the following ingredients are used: DALTOLAC R180: a non-amine initiated polyether polyol available from Imperial chemical Industries (f4.5, OH number 440 mgKOH/g). DALTOLAC R260: a non-amine initiated polyether polyol available from Imperial chemical Industries (OH number 310 mgKOH/g). DALTOLAC R130: a non-amine initiated polyether polyol available from Imperial chemical Industries (OH number 460 mgKOH/g). DALTOLAC R200: a non-amine initiated polyether polyol available from Imperial chemical Industries (OH number 380 mgKOH/g). DALTOLAC R090: a non-amine initiated polyether polyol available from Imperial chemical Industries (OH number 540 mgKOH/g). POLYOL X: a polyether polyol (f3.2, OH number 495mgKOH/g) initiated by polymethylene polyphenylene polyamine. POLYOL Y: a polyether polyol (OH number 310mgKOH/g) initiated by polymethylene polyphenylene polyamine. DALTOCEL F455: an ethylene oxide capped polyether polyol, available from Imperial chemical Industries (OH number 53-57 mgKOH/g). DALTOCEL F428: an ethylene oxide capped polyether polyol, available from Imperial chemical Industries (OH number 26-30 mgKOH/g). DALTOCEL F430: an ethylene oxide capped polyether polyol, available from Imperial chemical Industries (OH number 28-32 mgKOH/g). DALTOCEL F436: an ethylene oxide capped polyether polyol, available from Imperial chemical Industries (OH number 24-38 mgKOH/g). DALTOCEL F452: an ethylene oxide capped polyether polyol, available from Imperial chemical Industries (OH number 50-54 mgKOH/g). DALTOCEL F448: a non-ethylene oxide capped polyether polyol is available from Imperial Chemical Industries (OH number 46-50 mgKOH/g). POLYOL A: a polyol blend having an OH number of 417mgKOH/g comprising 60% by weight) of a polyether polyol initiated with a polymethylene polyphenylene polyamine. POLYOL B: polyol blend with OH value of 417mgKOH/gAnd it comprises a sucrose-initiated polyether polyol. POLYOL C: a polyol blend having an OH value of 417mgKOH/g comprising a sorbitol initiated polyether polyol. PPG 425: polypropylene glycol (MW 425) Polycat 8: a catalyst from Air Products. Polycat 5: a catalyst from Air Products. NIAX A1: a catalyst from Union Carbide. SFB: a catalyst from Imperial Chemical industries. L6900: a siloxane surfactant derived from OSi. B1400A: a silicone surfactant from Goldschmidt. B8461: a silicone surfactant from Goldschmidt. SURFYNOL: a non-silicone surfactant from Air Products. Emulsifier: perfluoro-C containing unsaturated bond_4-12A mixture of isomers. SUPRASEC DNR: polymeric MDI from Imperial Chemical Industries. SUPRASEC 2021: MDI prepolymers from Imperial Chemical Industries. Prepolymer: polyisocyanate composition obtained by reacting SUPRASEC DNR with 0.1% by weight (based on polyisocyanate) FC10, a perfluorooctanesulfonamide derived from 3M. DALTOLAX, DALTOCEL and SUPRASEC are trademarks of Imperial Chemical Industries. Example 1

Rigid foams were prepared from the ingredients listed in table 1 below. The cream time, stirring time and onset stop time were used to follow the reaction.

The following properties were measured: core density (according to DIN 53420), initial lambda value at 10 ℃ (according to ISO standard 2581) and compressive strength in the direction of and perpendicular to the rise (according to DIN 53421). The results are shown in Table 1.

These results show that the foams of the invention (foams No. 2 and 3) have a more isotropic structure and higher compressive strength for similar density and reaction profiles, especially in the direction perpendicular to the rise, better than the comparative foam containing a silicone-based surfactant (foam No. 1). In addition, it was observed that foam No. 1 shrunk, while foam nos. 2 and 3 did not shrink at all. The additional use of a fluorinated isocyanate-terminated prepolymer (foam No. 3) leads to improved thermal insulation (λ). Example 2

Rigid foams having an NCO index of 105 were prepared from the ingredients listed in Table 2.

Foams 5-12 are collapsed while foams 1-4 have a good foam structure, especially foams 3 and 4. TABLE 1

Number of foamed plastics		1	2	3
					Polyhydric alcohols
DALTOLAC R180	pbw	20	20	20
					POLYOL X	pbw	80	80	80
DALTOCEL F455	pbw	0	2	2
					Polycat 8	pbw	1	1	1
Polycat 5	pbw	0.3	0.3	0.3
					L 6900	pbw	2.5	0	0
Water (W)	pbw	1.63	1.63	1.63
					HCFC 141b	pbw	33.5	33.5	33.5
Isocyanates
					SUPRASEC DNR	pbw	155.78	155.28	0
Prepolymers	pbw	0	0	155.57
					Index of refraction		108	108	108
General description of the reaction
					Milk white period	sec	11	10	10
Time of stirring	sec	50	50	47
					Initiation termination time	sec	130	125	130
Density of core	kg/m3	26.3	26.9	27.5
					Initial lambda	mW/mK	19.5	21.0	19.1
Compressive strength
					Rise up	kPa	83	105	112
Vertical 1	kPa	65	92	115
					Vertical 2	kPa	178	117	141

TABLE 2

Number of foamed plastics		1	2	3	4	5	6	7	8	9	10	11	12
														Polyhydric alcohols
POLYOL A	pbw	100	100	100	100	0	0	0	0	0	0	0	0
														POLYOL B	pbw	0	0	0	0	100	100	100	100	0	0	0	0
POLYOL C	pbw	0	0	0	0	0	0	0	0	100	100	100	100
														DALTOCEL F455	pbw	0	0	2	2	0	0	2	2	0	0	2	2
Polycat 8	pbw	1.2	1.2	1.2	1.2	3.2	3.2	3.2	3.2	4	4	4	4
														NIAX A1	pbw	0.1	0.1	0.1	0.1	0.1	0.1	0.1	0.1	0.1	0.1	0.1	0.1
Water (W)	pbw	2.5	2.5	2.5	2.5	2.5	2.5	2.5	2.5	2.5	2.5	2.5	2.5
														HCFC 141b	pbw	21	21	21	21	21	21	21	21	21	21	21	21
Polyisocyanates
														SUPRASEC DNR	pbw	147	0	147	0	147	0	147	0	147	0	147	0
Prepolymers	pbw	0	147	0	147	0	147	0	147	0	147	0	147

Example 3

Rigid foams were prepared from the ingredients listed in table 3 below. The results in Table 3 show that the presence of an ammonia initiated polyether polyol in a silicone free formulation is necessary (compare foams 15 and 14). By the process of the present invention, a stable low density foam can be obtained (compare foams 15 and 13). TABLE 3

Number of foamed plastics		13	14	15
					Polyhydric alcohols
DALTOLAC R130	pbw	28.7	28.7	0
					POLYCL X	pbw	0	0	28.7
DALTCLAC R200	pbw	33.4	33.4	33.4
					PPG 425	pbw	9.6	9.6	0
DALTOCEL F455	pbw	0	0	9.6
					B 1400A	pbw	1.6	0	0
NIAX A1	pbw	0.18	0.18	0.18
					SFB	pbw	0.29	0.29	0.29
Pclycat 8	pbw	0.4	0.4	1.2
					Water (W)	pbw	3.65	3.65	3.65
Isocyanates
					SUPPASEC DNR	pbw	141.3	0	0
Prepolymers	pbw	0	141.25	139.1
					Quality of foam		Good effect	Shrivelled bubble	Good effect
Density of	kg/m2	32		29
					Stability of		Good effect		Good effect

Example 4

Rigid polyurethane foams were prepared from the ingredients listed in table 4. The foam properties were measured. The results are shown in Table 4. TABLE 4

Number of foamed plastics		16	17
				Polyhydric alcohols
DALTOLAC R130	pbw	28.7	0
				POLYOL X	pbw	0	28.7
DALTOLAC R200	pbw	33.4	33.4
				PPG 425	pbw	9.6	0
DALTOCEL F455	pbw	0	9.6
				DALTOLAC R090	pbw	9.6	9.6
B 1400A	pbw	1.6	0
				NIAX A1	pbw	0.18	0.18
SFB	pbw	0.29	0.29
				Polycat 8	pbw	0.7	0.35
Water (W)	pbw	5	5.2
				Isocyanates
SUPRASEC DNR	pbw	162.41	0
				prepolymer/SUPRASEC 202180/20	pbw	0	171.8
Density of	kg/m3	25	26
				Super-irrigation material		5	5
Compressive strength
				Height	kPa	8.4	83.5
Width of	kPa	66.9	112.0
				Length of	kPa	132.4	111.4
Average	kPa	93.2	102.3

Example 5

Rigid polyurethane foams were prepared from the ingredients listed in Table 5. The foam properties were measured. The results are shown in Table 5. The results shown in table 5 demonstrate that the thermal insulation performance is improved when additional non-silicone surfactants are used. TABLE 5

Number of foamed plastics		18	19
				Polyhydric alcohols
POLYOL X	pbw	21	21
				POLYOL Y	pbw	38	38
DALTOLAC R180	pbw	35.4	35.4
				DALTOCEL F428	pbw	2	2
NIAX A1	pbw	0.3	0.3
				Polycat8	pbw	1.3	1.3
Cyclopentane	pbw	14	14
				Emulsifier	pbw	0	3
Water (W)	pbw	2.33	2.33
				Isocyanates
Prepolymers	pbw	143	145
				Density of	kg/m3	25.8	26.8
Lambda value	mW/mK	22.2	20.6

Example 6

Rigid polyurethane foams were prepared from the ingredients listed in Table 6. The foam properties were measured. The results are shown in Table 6. The results shown in Table 6 demonstrate that the compressive strength can be improved using the foams of the present invention. TABLE 6

Number of foamed plastics		20	21
				Polyhydric alcohols
POLYOL X	pbw	21	21
				POLYOL Y	pbw	38	38
DALTOLAC R180	pbw	35.4	35.4
				DALTOCEL F428	pbw	0	2
B 8461	pbw	2	0
				NIAX A1	pbw	0.3	0.3
Polycat 8	pbw	1.3	1.3
				Cyclopentane	pbw	14	14
Water (W)	pbw	2.33	2.33
				Isocyanates
SUPRASEC DNR	pbw	142.8	143.1
				Density of	kg/m3	25.3	24.8
Compressive strength
				Height	kPa	106.3	99.0
Width of	kPa	76.6	98.1
				Length of	kPa	94.0	85.6
Average	kPa	93.1	94.4
				Lambda value	mW/mK	21.7	22.4

Example 7

Rigid polyurethane foams were prepared from the ingredients listed in Table 7. The foam properties were measured. The results are shown in Table 7. TABLE 7

Number of foamed plastics		22	23	24	25	26
							Polyhydric alcohols
POLYOL X	pbw	21	21	21	21	21
							POLYOL Y	pbw	38	38	38	38	38
DALTOLAC R180	pbw	35.4	35.4	35.4	35.4	35.4
							DALTOCEL F428	pbw	2	2	2	2	2
SURFYNOL 420	pbw	0	2	0	0	0
							SURFYNOL 440	pbw	0	0	2	0	0
SURFYNOL 465	pbw	0	0	0	2	0
							SURFYNOL 485	pbw	0	0	0	0	2
NIAX A1	pbw	0.3	0.3	0.3	0.3	0.3
							Polycat 8	pbw	1.3	1.3	1.3	1.3	1.3
Cyclopentane	pbw	14	14	14	14	14
							Water (W)	pbw	2.33	2.33	2.33	2.33	2.33
Isocyanates
							SUPRASEC DNR	pbw	143.1	143.1	143.1	143.1	143.1
Density of	kg/m3	30.5	30.6	30.3	30.0	30.3
							Compressive strength
Height	kPa	127.9	125.4	133.4	126.6	123.8
							Width of	kPa	111.7	119.1	107.3	105.9	106.5
Length of	kPa	114.2	123.4	108.8	114.4	102.8
							Average	kPa	118.1	122.7	117.1	115.9	111.4
Lambda value	mW/mK	22.2	22.3	22.8	22.1	23.1

Example 8

Rigid foams having an NCO index of 112 were prepared from the ingredients listed in Table 8 below.

The results in Table 8 show that more isotropic foams are obtained by the process of the invention. TABLE 8

Number of foamed plastics		27	28	29
					Polyhydric alcohols
POLYOL X	pbw	21	21	21
					POLYOL Y	pbw	38	38	38
DALTOLAC R180	pbw	35.4	35.4	35.4
					DALTOCEL F428	pbw	0	0	2
B 8461	pbw	2	0	0
					NIAX A1	pbw	0.3	0.3	0.3
Polycat 8	pbw	1.3	1.3	1.3
					Cyclopentane	pbw	12	14	14
Water (W)	pbw	2	2.33	2.33
					Isocyanates
SUPRASEC DNR	pbw	137.0	143.0	0
					Prepolymers	pbw	0	0	143.0
Density of core	kg/m3	32.6	29.9	29.7
					Flow of	cm/g	0.35	0.33	0.34
Compressive strength
					Rise up	kPa	166	132	142
Length of	kPa	173	139	159
					Width of	kPa	146	132	144

Example 9

Rigid polyurethane foams were prepared from the ingredients listed in table 9 below. The results in Table 9 show that it is beneficial to use known polyether polyols for the preparation of ethylene oxide-capped flexible polyurethane foams. TABLE 9

Number of foamed plastics		30	31	32	33	34	35
								Polyhydric alcohols
POLYOL X	pbw	21	21	21	21	21	21
								POLYOL Y	pbw	38	38	38	38	38	38
DALTOLAC R180	pbw	35.4	35.4	35.4	35.4	35.4	35.4
								DALTOCEL F428	pbw	2	0	0	0	0	0
DALTOCEL F430	pbw	0	2	0	0	0	0
								DALTOCEL F436	pbw	0	0	2	0	0	0
DALTOCEL F448	pbw	0	0	1	2	0	0
								DALTOCEL F452	pbw	0	0	0	0	2	0
DALTOCEL F455	pbw	0	0	0	0	0	2
								NIAX A1	pbw	0.3	0.3	0.3	0.3	0.3	0.3
Polycat 8	pbw	1.3	1.3	1.3	1.3	1.3	1.3
								Cyclopentane	pbw	14	14	14	14	14	14
Water (W)	pbw	2.33	2.33	2.33	2.33	2.33	2.33
								Isocyanates
Prepolymers	pbw	143.0	143.0	143.0	143.0	143.0	143.0
								Quality of foam		Good effect	Good effect	In general	Roughness of	In general	In general

Example 10

Rigid polyurethane foams were prepared from the ingredients listed in table 10 below. The results in Table 10 show the effect of the amine initiated polyether polyol (amount). Example 11

Rigid polyurethane foams were prepared from the ingredients listed in table 11 below. The results in Table 11 show the effect of amine initiated polyether polyols. Watch 10

Number of foamed plastics		36	37	38	39	40	41	42	43	44	45	46	47
														Polyhydric alcohols
POLYOL X	pbw	64	64	64	64	32	32	32	32	16	16	16	16
														DALTOLAC R180	pbw	16	16	16	16	48	48	48	48	64	64	64	64
DALTOCEL F428	pbw	0.8	1.6	4	8	0.8	1.6	4	8	0.8	1.6	4	8
														NIAX A1	pbw	0.3	0.3	0.3	0.3	0.3	0.3	0.3	0.3	0.3	0.3	0.3	0.3
Polycat 8	pbw	1.3	1.3	1.3	1.3	1.3	1.3	1.3	1.3	1.3	1.3	1.3	1.3
														Cyclopentane	pbw	14	14	14	14	14	14	14	14	14	14	14	14
Water (W)	pbw	2.33	2.33	2.33	2.33	2.33	2.33	2.33	2.33	2.33	2.33	2.33	2.33
														Isocyanates
Prepolymers	pbw	143	143	143	143	143	143	143	143	143	143	143	143
														Quality of foam		Good effect	Good effect	Good effect	Soft and soft	In general	Good effect	Good effect	Soft and soft	Shrivelled bubble	Roughness of	Soft and soft	Soft and soft

TABLE 11

Number of foamed plastics		48	49	50	51	52	53	54	55	56	57	58	59
														Polyhydric alcohols
POLYOL X	pbw	58	58	58	58	0	0	0	0	0	0	0	0
														POLYOL Y	pbw	42	42	42	42	0	0	0	0	0	0	0	0
DALTOLAC R180	pbw	0	0	0	0	83	83	83	83	0	0	0	0
														DALTOLAC R260	pbw	0	0	0	0	17	17	17	17	0	0	0	0
DALTOLAC R130	pbw	0	0	0	0	0	0	0	0	47	47	47	47
														DALTOLAC R200	pbw	0	0	0	0	0	0	0	0	53	53	53	53
DALTOCEL F455	pbw	0	0	2	2	0	0	2	2	0	0	2	2
														NIAX A1	pbw	0.1	0.1	0.1	0.1	0.1	0.1	0.1	0.1	0.1	0.1	0.1	0.1
Polycat 8	pbw	1.2	1.2	1.2	1.2	3.2	3.2	3.2	3.2	4	4	4	4
														HCFC 141b	pbw	21	21	21	21	21	21	21	21	21	21	21	21
Water (W)	pbw	2.5	2.5	2.5	2.5	2.5	2.5	2.5	2.5	2.5	2.5	2.5	2.5
														Isocyanates
SUPRASEC DNR	pbw	147	0	147	0	147	0	147	0	147	0	147	0
														Prepolymers	pbw	0	147	0	147	0	147	0	147	0	147	0	147
Quality of foam		Shrivelled bubble	In general	Good effect	Good effect	Shrivelled bubble	Shrivelled bubble	Shrivelled bubble	Shrivelled bubble	Shrivelled bubble	Shrivelled bubble	Shrivelled bubble	Soft and soft

Example 12

Rigid foams having an NCO index of 108 were prepared from the ingredients listed in Table 12 below.

The results in Table 12 show that a more stable foam of lower density (dimensional stability measured according to ISO standard 2796) is obtained with the process of the invention. The fluidity is also improved. The use of non-silicone surfactants can further improve the thermal insulation properties. TABLE 12

Number of foamed plastics		60	61	62
					Polyhydric alcohols
POLYOL X	pbw	80	80	80
					DALTOLAC R180	pbw	20	20	20
DALTOCEL F428	pbw	0	2.5	2.5
					L 6900	pbw	2.5	0	0
Polycat 8	pbw	1	1	1
					Polycat 5	pbw	0.3	0.3	0.3
HCFC 141b	pbw	33.5	37	37
					Water (W)	pbw	1.63	2	2
Isocyanates
					SUPRASEC DNR	pbw	155.28	161.36	0
Prepolymers	pbw	0	0	161.36
					Emulsifier	pbw	0	0	3.23
Bulk density	kg/m2	31.8	28.5	28.5
					Flow of	cm/g	0.31	0.35	0.36
Compressive strength
					Rise up	kPa	70.5	94	86
Length of	kPa	160.3	107.4	115.8
					Width of	kPa	86.8	106.6	105.1

Dimensional stability
					1 day-20 deg.C	％	6.95	0.09	0.16
70 ℃ for 1 day	％	1.53	0.91	0.77
					100 ℃ for 1 day	％	2.08	1.63	1.62
70 ℃/100% RH for 1 day	％	4.56	4.19	4.49
					14 days-20 deg.C	％	17.8	0.61	0.28
70 ℃ for 14 days	％	2.98	2.98	3.01
					100 ℃ for 14 days	％	3.88	4.23	4.32
70 ℃/100% RH for 14 days	％	6.98	3.8	7.49
					Lambda value
Initial	mW/mK	17.2	18.1	17.4
					1 week/70 deg.C	mW/mK	19.5
3 weeks/70 deg.C	mW/mK	21.2	22.1	21
					5 weeks/70 deg.C	mW/mK	22.3	22.9	22.2

Claims (21)

1. A process for the preparation of a rigid polyurethane or urethane-modified polyisocyanurate foam comprising reacting a polyisocyanate composition with a polyfunctional isocyanate-reactive composition in the absence of a silicone-based surfactant characterised in that the polyfunctional isocyanate-reactive composition comprises an amine-initiated polyether polyol.

2. The process according to claim 1 wherein the amine-initiated polyether polyol is the reaction product of an alkylene oxide with an ammonia initiator containing from 2 to 8 active hydrogen atoms per molecule.

3. The process of claim 2 wherein the initiator is an aromatic amine.

4. The method of claim 3 wherein the ammonia initiator is a polymethylene polyphenylene polyamine.

5. The process according to any of the preceding claims, wherein the ammonia-initiated polyether polyol has an OH number of 300-1000 mgKOH/g.

6. A process according to any one of the preceding claims wherein the ammonia-initiated polyether polyol is present in an amount of at least 20% by weight of the total isocyanate-reactive mixture.

7. The process according to any one of the preceding claims wherein the polyfunctional isocyanate-reactive composition further comprises a polyether polyol having an average nominal functionality of 2-6 and a number average molecular weight of 1000-10000.

8. The process according to claim 7, wherein the polyether polyol has an average nominal functionality of from 2 to 4.

9. A process according to claim 7 or 8, wherein the polyether polyol has an OH number of from 20 to 80 mgKOH/g.

10. A process according to claim 7, 8 or 9 wherein the polyether polyol is a polyoxypropylene diol or triol or a poly (oxyethylene-oxypropylene) diol or triol obtained by the simultaneous or sequential addition of ethylene oxide and propylene oxide to a di-or tri-functional initiator.

11. The process of claim 10 wherein said or trifunctional initiator is selected from the group consisting of ethylene glycol, diethylene glycol, dipropylene glycol, and glycerol.

12. A process according to claim 10 or 11 wherein the polyether polyol is an ethylene oxide-terminated block copolymer having an ethylene oxide content of at least 7% by weight based on the total amount of alkylene oxide units.

13. A process according to claims 7 to 12 wherein the polyether polyol is used in an amount of from 1 to 25% by weight based on the total amount of isocyanate-reactive components.

14. A process according to any preceding claim wherein the polyisocyanate composition comprises the reaction product of a stoichiometric excess of an organic polyisocyanate and a substantially fluorinated isocyanate-reactive compound.

15. The process according to claim 14 wherein said substantially fluorinated isocyanate-reactive compound has a structural formula corresponding to the following formula (I):wherein A is a substantially fluorinated or perfluorinated, linear or branched alkyl group having 2 to 10 carbon atoms; n is an integer from 1 to 11; x is 0 or 1; r is hydrogen or C_1-12Alkyl or R '-OH, wherein R' is C_1-12An alkylene group.

16. The method according to claim 15, wherein n is 1 or 2, and A is perfluoro C_3-10Straight or branched alkyl, R is hydrogen or C_1-4Alkyl and R' is C_1-4An alkylene group.

17. The process according to claim 14, 15 or 16 wherein the organic polyisocyanate reacted with the substantially fluorinated isocyanate reactive compound is diphenylmethane diisocyanate in the form of a 2, 4 ' -, 2, 2 ' -or 4, 4 ' -isomer or a mixture thereof, or polymethylene polyphenylene polyisocyanate.

18. A process according to claims 14 to 17 wherein the substantially fluorinated isocyanate-reactive compound is present in an amount of from 0.02 to 5% by weight based on the weight of the organic polyisocyanate.

19. A process according to any preceding claim, wherein the process is carried out in the presence of a blowing agent selected from hydrocarbons and hydrofluorocarbons.

20. A method according to any preceding claim, wherein the foaming formulation comprises a non-silicone based surfactant.

21. Rigid polyurethane or urethane-modified polyisocyanurate foam obtainable by the process as defined in any one of the preceding claims.