PRODUCTION OF POLYURETHANE FOAM

Abstract

A composition for producing rigid PU foam contains at least one polyisocyanate component, at least one polyol component, a blowing agent, a solid flame retardant, and optionally, a catalyst that catalyzes the formation of a urethane or isocyanurate linkage. The composition also contains at least one surfactant based on a quaternary ammonium compound.

Claims

1: A composition for producing rigid PU foam, comprising: at least one polyisocyanate component, at least one polyol component, a blowing agent, a solid flame retardant, optionally, a catalyst that catalyses the formation of a urethane or isocyanurate linkage, and at least one surfactant based on a quaternary ammonium compound.

2: The composition according to claim 1, wherein the quaternary ammonium compound is at least one ester quat of the formula (1) or (2), an alkyl quat of the formula (3), an imidazolinium quat of the formula (4), an amidoamine quat of the formula (5) and/or cetylpyridinium chloride, wherein in ##STR00005## R.sup.1 is an acyl radical of a saturated or mono- or polyunsaturated, linear or branched fatty acid having a chain length of 8 to 22 carbon atoms or the acyl radical of ricinoleic acid, or hydrogen, it being possible for a compound of the formula (1) or (2) to contain different radicals R.sup.1, and with the proviso that at least one radical R.sup.1 must be one of the named acyl radicals, R.sup.2 is an alkyl radical having 1 to 6 carbon atoms or hydrogen, R.sup.3 is an alkyl radical having 1 to 6 carbon atoms or hydrogen, R.sup.4 is an alkyl radical having 1 to 6 carbon atoms or a hydroxyethyl radical or hydrogen, it being possible for a compound of the formula (1) or (2) to contain different radicals R.sup.4, and n=0 to 20, a=1 to 3 and b=1 to 3, with the proviso that a+b=4, and/or wherein in ##STR00006## R.sup.5 is a saturated or mono- or polyunsaturated, linear or branched alkyl radical having a chain length of 8 to 24 carbon atoms, it being possible for a compound of the formula (3) to contain different radicals R.sup.5, R.sup.6 is an alkyl radical having 1 to 6 carbon atoms or a hydroxyethyl radical or a benzyl radical or hydrogen, it being possible for a compound of the formula (3) to contain different radicals R.sup.6, and c=1 to 3 and d=1 to 3, with the proviso that c+d=4, and/or wherein in ##STR00007## R.sup.7 is an alkyl radical having 1 to 6 carbon atoms or a hydroxyethyl radical or hydrogen, R.sup.8 is a saturated or mono- or polyunsaturated, linear or branched alkyl radical having 8 to 22 carbon atoms or a radical O(CO)R.sup.10, where R.sup.10 is an aliphatic, saturated or mono- or polyunsaturated, linear or branched alkyl radical having 7 to 21 carbon atoms, R.sup.9 is an aliphatic, saturated or mono- or polyunsaturated, linear or branched alkyl radical having 7 to 21 carbon atoms, Z is an NH group or oxygen, where e is an integer from 1 to 4, and/or wherein in ##STR00008## R.sup.11 is a saturated or mono- or polyunsaturated, linear or branched alkyl radical having a chain length of 7 to 21 carbon atoms, R.sup.12 is an alkyl radical having 1 to 6 carbon atoms or a hydroxyethyl radical or hydrogen, it being possible for a compound of the formula (5) to contain different radicals R.sub.12, and f is an integer from 0 to 5, h=1 or 2 and g=2 or 3, with the proviso that h+g=4, it being possible for a compound of the formula (5) in which h=2 to have different values for f and to contain different radicals R.sup.11; and where R.sup.4, R.sup.6, R.sup.7 or R.sup.12 comprises a hydroxyethyl radical which may also be alkoxylated, and said optionally alkoxylated hydroxyethyl radical may contain repeat units based on ethylene oxide, propylene oxide, butylene oxide and/or styrene oxide and comprise 1-15 repeat units.

3: The composition according to claim 2, wherein, in formula (1) and/or formula (2), R.sup.1 is selected from acyl radicals of acids from the group consisting of oleic acid, isostearic acid, lauric acid, palmitic acid, elaidic acid, vaccenic acid, gadoleic acid, eicosenoic acid, cetoleic acid, erucic acid, nervonic acid, linoleic acid, alpha-linolenic acid, gamma-linolenic acid, calendic acid, punicic acid, alpha-eleostearic acid, beta-eleostearic acid, arachidonic acid, timnodonic acid, clupanodonic acids and cervonic acid.

4: The composition according to claim 2, wherein, in formula (1), a=b=2, and/or in formula (5), h=1 and g=3.

5: The composition according to claim 2, additionally comprising: at least one counteranion to compounds of the general formulas (1), (2), (3), (4) and/or (5), selected from the group consisting of chloride, bromide, iodide, alkylsulfate, alkylsulfonate, triflate, tosylate, phosphate, sulfate, hydrogensulfate, lactate, glycolate, acetate, and citrate.

6: The composition according to claim 1, wherein the at least one surfactant based on a quaternary ammonium compound is present in a total amount of 0.1 to 10 parts, based on 100 parts of polyols.

7: The composition according to claim 1, wherein the composition comprises, as the solid flame retardant, ammonium polyphosphate, melamine, melamine cyanurate and/or red phosphorus.

8: The composition according to claim 1, wherein the composition comprises, as the solid flame retardant, ammonium polyphosphate and melamine, or ammonium polyphosphate coated with or encased in melamine, or ammonium polyphosphate microencapsulated with melamine or with melamine-formaldehyde resin.

9: The composition according to claim 1, wherein the solid flame retardant is present in a total amount of 1 to 60 parts, based on 100 parts of polyols.

10: The composition according to claim 1, wherein the composition additionally comprises: at least one foam stabilizer, in amounts of 0.5 to 4 parts, based on 100 parts of polyols.

11: A process, comprising: producing a rigid PU foam based on a foamable reaction mixture comprising at least one polyisocyanate, at least one polyol component, a blowing agent, a solid flame retardant, optionally, a catalyst, optionally, other additives, and at least one surfactant based on a quaternary ammonium compound.

12: A rigid PU foams produced by the process according to claim 11.

13: The rigid PU foam according to claim 12, as wherein the rigid PU foam is an insulating material and/or a construction material.

14: A method, comprising: producing a rigid PU foam from a composition comprising a solid flame retardant, and with a surfactant based on quaternary ammonium compounds, as a dispersing additive.

15: The method according to claim 14, wherein the surfactant based on quaternary ammonium compounds improves dispersibility, redispersibility, and/or sedimentation stability of the solid flame retardant.

16: The method according to claim 2, wherein in formula (1) or (2), R.sup.2 is hydrogen or methyl, R.sup.3 is hydrogen or methyl, and R.sup.4 is methyl.

17: The method according to claim 2, wherein in formula (3), R.sup.6 is methyl.

18: The method according to claim 2, wherein in formula (4), R.sup.7 is methyl.

19: The method according to claim 2, wherein in formula (5), R.sup.12 is methyl.

20: The composition according to claim 7, wherein the solid flame retardant is ammonium polyphosphate.

Description

EXAMPLES

Example 1: Sedimentation Stability

[0098] The performance comparison was carried out using the formulations shown in Table 2. For this, 100 g of polyol, according to the example, catalysts, water and foam stabilizer were weighed out and mixed with a disc stirrer (diameter 6 cm) at 1000 rpm for 30 s. The compound of the invention was then added and mixed in with a disc stirrer (diameter 6 cm) at 2000 rpm for 30 s. For the reference experiment, the same mixture, but without addition of the compound of the invention, was likewise mixed at 2000 rpm for a further 30 s. Ammonium polyphosphate as a solid flame retardant was then added with the disc stirrer still running at 2000 rpm and mixed in for a further 45 s. The formulations were then transferred to glass vessels and sealed, and the time until complete sedimentation was measured.

TABLE-US-00002 TABLE 2 Formulations (composition in parts by weight) Formulation 1 2 3 4 5 6 7 8 Polyether polyol* 100 100 Polyester polyol 1** 100 100 100 100 Polyester polyol 2*** 100 100 Ammonium 10 10 10 10 10 10 30 40 polyphosphate Ester quat EQ 1 0.5 0.5 0.5 0.5 0.5 0.5 1.5 2.0 POLYCAT? 8.sup.# 2 POLYCAT? 5.sup.# 0.5 0.5 KOSMOS? 75.sup.# 4 4 TEGOSTAB? 8491.sup.## 2.5 2.0 2 Water 2 0.8 0.8 *Daltolac? R 471 from Huntsman, **Stepanpol? PS 3152 from Stepan, ***Isoexter? 4973 from Coim, .sup.#Catalysts from Evonik Operations GmbH .sup.##Polyether siloxane-based foam stabilizer from Evonik Operations GmbH

[0099] As a compound of the invention, an ester quat (EQ 1) obtainable by reaction of diisopropanolmethylamine with isostearic acid and oleic acid and subsequent methylation with dimethyl sulfate was used.

TABLE-US-00003 TABLE 3 Sedimentation stability Sedimentation stability in h Sedimentation stability in h Formulation without EQ 1 (reference) with EQ 1 1 15 24 2 12 18 3 48 72 4 24 32 5 48 72 6 24 32 7 24 72 8 72 >120

[0100] In all cases a clear improvement in sedimentation stability was achieved compared to the formulation without ester quat.

Example 2: Redispersibility

[0101] For the performance comparison, the extent to which the formulations described in example 1 can be redispersed was checked. This was done by storing all formulations in an upright position at room temperature for 14 days until complete sedimentation of the solids in all cases. The samples were then all redispersed and assessed on the basis of a scale from 1 to 3. In this scale, a score of 1 means that the sample could already be brought back into dispersion by manually shaking the glass vessel for 30 s. A score of 2 means that, although not possible by manual shaking, the sample could be redispersed using an electric laboratory stirrer (500 rpm for 60 s). A score of 3 was awarded to samples in which a very fine, compact sediment had formed that could not be redispersed by the two methods mentioned above.

TABLE-US-00004 TABLE 4 Redispersibility Redispersibility Redispersibility Formulation without EQ 1 (reference) with EQ 1 1 2 1 2 2 1 3 3 1 4 2 1 5 3 1 6 2 1 7 3 1 8 3 1

[0102] In all investigated cases, the compound of the invention achieved a clear improvement in redispersibility. In particular, the use of polyester polyols avoided the formation of a solid, compact sediment.

[0103] The invention therefore permits very good redispersibility of the solids in the event of sedimentation after very long storage, which means that constant stirring or mixing, for example, during storage is no longer necessary.

Example 3: Viscosity

[0104] For the performance comparison of processability, the influence on viscosity of the compound of the invention was investigated. The selected base polyol was a polyester polyol from Stepan (Stepanpol? PS 2352). The formulations described in table 5 were produced in analogous manner to the description in example 1. The ester quat selected was the compound EQ 1 of the invention that was described in example 1. The selected reference additive for dispersion was a TEGO? Dispers 1010 from Evonik Operations GmbH. The viscosity was measured at different shear rates using an Anton Paar MCR 302 rheometer (50 mm plate-plate, 0.5 mm gap) at 25? C.

TABLE-US-00005 TABLE 5 Viscosity (parts APP and EQ 1 based on 100 parts polyol) Viscosity at a Viscosity at a Formulation shear rate of 0.2 1/s shear rate of 100 1/s Polyol 3200 mPa*s 3180 mPa*s Polyol + 50 parts APP 12 700 mPa*s 6400 mPa*s Polyol + 50 parts APP + 68 000 mPa*s 6700 mPa*s 2.5 pphp reference additive Polyol + 50 parts APP + 24 000 mPa*s 3260 mPa*s 0.5 parts EQ 1

[0105] The use of the ester quat of the invention increases the viscosity at low shear rates only moderately, whereas customary dispersing additives bring a pronounced increase in viscosity. At higher shear rates it is possible to achieve a clear reduction in viscosity compared to customary dispersing additives. In the present example the viscosity in fact achieves the level of the base polyol. This brings clear advantages in processing and storage with regard to process technology requirements.

Example 4: Rigid PIR Foam (PIR=Polyisocyanurate)

[0106] The following foam formulation was used for the performance comparison:

TABLE-US-00006 TABLE 6 Rigid PIR foam formulation Component Proportion by weight Polyester polyol* 100 Amine catalyst** 0.6 Potassium trimerization catalyst*** 3 Surfactant**** 2 Water 0.8 Ester quat EQ 1 0 or 0.5 APP 10 or 15 Cyclopentane/isopentane 70:30 18 MDI***** 273 *Stepanpol? PS 3152 from Stepan, OH value 315 mg KOH/g **POLYCAT? 5 from Evonik Operations GmbH ***KOSMOS? 75 from Evonik Operations GmbH ****TEGOSTAB? B 84504 from Evonik Operations GmbH *****Polymeric MDI, 200 mPa*s, 31.5% NCO, functionality 2.7.

[0107] The comparative foamings were carried out by manual mixing. For this, polyol, catalysts, water, foam stabilizer, optionally ester quat EQ 1, ammonium polyphosphate and blowing agent were weighed into a beaker and mixed with a disc stirrer (diameter 6 cm) at 1000 rpm for 30 s (batch size 500 g). The beaker was reweighed to determine the amount of blowing agent that had evaporated during the mixing operation and this was replenished. The MDI was then added, and the reaction mixture was stirred with the described stirrer at 3000 rpm for 5 s and immediately transferred to a 25 cm?50 cm?7 cm aluminium mould lined with polyethylene film and thermostatted to 60? C.

[0108] After 10 min, the foams were demoulded. One day after foaming, the foams were analysed. Surface and internal defects were assessed subjectively on a scale from 1 to 10, where 10 represents an (idealized) defect-free foam and 1 represents a very significantly defective foam. The thermal conductivity coefficient (A value in mW/m-K) was measured on 2.5 cm-thick discs with an instrument of the Hesto Lambda Control type, model HLC X206, at an average temperature of 10? C. in accordance with the specifications of standard EN12667:2001. The fire performance was determined by the small-burner test (B2) in accordance with DIN 4102-1:1998-05.

[0109] The results are compiled in the table below:

TABLE-US-00007 TABLE 7 Rigid PIR foam Formulation 10 pphp APP 10 pphp APP 15 pphp APP 15 pphp APP 0 pphp EQ 1 0.5 pphp EQ 1 0 pphp EQ 1 0.5 pphp EQ 1 Density in 38.0 38.1 38.9 38.8 kg/m.sup.3 ? value in 23.2 23.1 23.6 23.7 mW/m .Math. K Surface 6.5 7.5 6.0 7.5 Internal 7.0 8.0 6.5 7.5 defects Flame 138 135 120 120 height in mm (B2) Cream 35 33 31 30 time in s Gel time 83 81 79 80 in s Rise time 105 102 101 97 in s Tack-free 173 173 172 170 time in s

[0110] The results show that the relevant foam properties are affected only negligibly or not at all by the compounds of the invention. Through the use of the compounds of the invention, it is moreover possible to achieve a more homogeneous distribution of the solid flame retardant in the foam, which is manifested in a significant improvement in the surface and also in pore structure/internal defects.

Example 5: Behaviour of Other Compounds According to the Invention

[0111] Further compounds according to the invention were compared with noninventive compounds in analogous manner to the procedure described in examples 1 to 4.

[0112] The performance comparison was carried out using the formulation shown in Table 8.

TABLE-US-00008 TABLE 8 Rigid PIR foam formulation Component Proportion by weight Polyester polyol* 100 Amine catalyst ** 0.6 Potassium trimerization catalyst*** 5 Surfactant**** 2 Water 0.8 Compound according to the invention 0.5 APP 10 Cyclopentane/isopentane 70:30 18 MDI***** 286 *Stepanpol? PS 3152 from Stepan, OH value 315 mg KOH/g ** POLYCAT? 5 from Evonik Operations GmbH ***DABCO? TMR 12 from Evonik Operations GmbH ****TEGOSTAB? B 84504 from Evonik Operations GmbH *****Polymeric MDI, 200 mPa*s, 31.5% NCO, functionality 2.7.

[0113] The compounds shown in Table 9 were investigated.

TABLE-US-00009 TABLE 9 Compounds investigated Name Type Composition Ester quat EQ 1 Ester quat See example 1 Ester quat EQ 2 Ester quat Methyl, hydroxyethyl, dihydroxyethyl oleate ester quat (methylsulfate) Ester quat EQ 3 Ester quat Methyl, hydroxyethyl, dihydroxyethyl tallowate ester quat (methylsulfate) Ester quat EQ 4 Ester quat Methyl, hydroxyethyl, dihydroxyethyl palmitate ester quat (methylsulfate) Ester quat EQ 5 Ester quat Dimethyl, dihydroxyethyl tallowate ester quat (chloride) Alkyl quat AQ 1 Alkyl quat Behenyl (C22) trimethylammonium chloride Alkyl quat AQ 2 Alkyl quat Distearyl dimethylammonium chloride Alkyl quat AQ 3 Alkyl quat Ethyl bis(polyethylene glycol)tallyl ammonium ethylsulfate (total 10 EO units) Alkyl quat AQ 4 Alkyl quat Methyl bis(polyethylene oxide)coco ammonium chloride (total 15 EO units) Alkyl quat AQ 5 Alkyl quat Methyl bis(polyethylene oxide)coco ammonium methylsulfate (total 5 EO units) Imidazolinium Imida- Dioleyl imidazolinium quat quat IQ 1 zolinium (methylsulfate, R.sup.7 = methyl, e = 2, quats Z = N) Imidazolinium Imida- Dipalmityl imidazolinium quat quat IQ 2 zolinium (methylsulfate, R.sup.7 = methyl, e = 2, quats Z = N) Amidoamine Amidoamine Methyl, polyethylene oxide, dipalm quat AmQ1 quat stearin amidoamine quat (f = 0, 3.5 EO, methylsulfate) Amidoamine Amidoamine Methyl, polyethylene oxide, quat AmQ2 quat diisostearin amidoamine quat (f = 0, 3.0 EO, methylsulfate) Cetylpyridinium chloride TEGOPREN? Silicone quat Noninventive 6921 TEGOTEX? Silicone quat Noninventive 8080 TEGO? Modified Noninventive Dispers 652 derivative based on tall oil Thixatrol? Modified Noninventive ST derivative based on castor oil

[0114] The compounds according to the invention were compared with commercially available noninventive surfactants (TEGOPREN? 6921, TEGOTEX? 8080, TEGO? Dispers 652, Thixatrol? ST).

[0115] The results for foam properties shown in Table 10 were obtained in analogous manner to the procedure described in example 4.

TABLE-US-00010 TABLE 10 Foam properties of rigid PIR foam Density ? value Cell structure Flame in in (surface/internal height in Compound kg/m.sup.3 mW/m .Math. K defects) mm (B2) Without dispersing 37.8 23.0 6.5/7.0 130 additive Ester quat EQ 1 38.0 22.9 7.5/7.5 125 Ester quat EQ 2 37.9 23.2 7.0/7.5 130 Ester quat EQ 3 37.8 23.1 8.0/8.0 135 Ester quat EQ 4 38.1 23.0 7.5/7.5 130 Ester quat EQ 5 37.7 22.9 7.0/7.5 130 Alkyl quat AQ 1 37.9 23.3 7.0/7.0 130 Alkyl quat AQ 2 37.6 23.1 7.5/8.0 130 Alkyl quat AQ 3 38.2 23.1 6.5/7.5 125 Alkyl quat AQ 4 37.4 23.0 7.0/7.0 130 Alkyl quat AQ 5 37.8 22.8 7.5/7.5 135 Imidazolinium 37.9 23.0 7.0/7.5 130 quat IQ 1 Imidazolinium 38.0 22.9 6.5/7.5 130 quat IQ 2 Amidoamine quat 38.1 23.2 7.0/7.5 128 AmQ1 Amidoamine quat 37.9 23.2 7.0/ 7.5 125 AmQ2 Cetylpyridinium 38.0 23.0 6.5/6.5 130 chloride TEGOPREN? 3.0/2.0 (very 6921 adversely affected) TEGOTEX? Collapse 8080 TEGO? 38.0 23.2 6.0/6.0 140 Dispers 652 Thixatrol? ST 38.4 23.6 6.0/6.0 140

[0116] The results show that the relevant foam properties are affected only negligibly or not at all by the compounds of the invention. Through the use of the compounds of the invention, it is moreover possible to achieve a more homogeneous distribution of the solid flame retardant in the foam, which is manifested in a significant improvement in the surface and also in pore structure/internal defects. The noninventive compounds on the other hand led to a severe coarsening of the foam (TEOGPREN? 6921), to collapse (TEGOTEX? 8080) or showed no improvement in foam structure (TEGO? Dispers 652, Thixatrol? ST).

[0117] The results for sedimentation stability, redispersibility and viscosity shown in Table 11 were obtained in analogous manner to the procedure described in examples 1 to 3. Sedimentation stability and redispersibility were determined using the formulation described in Table 8 (without MDI, without cyclo/isopentane). For the determination of viscosity, a formulation consisting of 10 parts of APP, 0.5 parts of dispersing additive and 100 parts of polyester polyol (Stepanpol? PS 3152) was prepared as described in example 1. Viscosity was determined in analogous manner to example 3.

TABLE-US-00011 TABLE 11 Dispersing behaviour Sedimen- Viscosity Viscosity tation Redispers- at 0.2 1/s at 100 1/s Compound stability ibility in Pa*s in Pa*s Without dispersing 24 h 2 6.2 3.3 additive Ester quat EQ 1 32 h 1 2.8 2.6 Ester quat EQ 2 32 h 1 8.2 2.9 Ester quat EQ 3 48 h 1 4.3 3.2 Ester quat EQ 4 48 h 1 4.5 3.4 Ester quat EQ 5 72 h 1 6.5 3.5 Alkyl quat AQ 1 32 h 1 4.4 3.1 Alkyl quat AQ 2 32 h 1 4.6 3.4 Alkyl quat AQ 3 32 h 1 4.0 2.9 Alkyl quat AQ 4 32 h 1 4.6 3.2 Alkyl quat AQ 5 32 h 1 4.3 2.8 Imidazolinium quat 48 h 1 6.8 3.4 IQ 1 Imidazolinium quat 32 h 1 6.7 3.5 IQ 2 Amidoamine quat 72 h 1 4.5 3.4 AmQ1 Amidoamine quat 32 h 1 6.4 3.1 AmQ2 Cetylpyridinium 32 h 1 3.6 3.1 chloride TEGOPREN? 6921 Not tested, as foam very adversely affected TEGOTEX? 8080 Not tested, as foam very adversely affected TEGO? Dispers 652 24 h 1 6.9 3.4 Thixatrol? ST 18 h 2 9.1 3.5

[0118] In all cases investigated, an improvement in sedimentation stability and in redispersibility was achieved compared to formulations without compounds according to the invention and compared to noninventive surfactants.

[0119] In particular, the use of polyester polyols allowed the formation of a solid, compact sediment to be avoided.

[0120] The use of the compounds of the invention increases the viscosity at low shear rates only moderately, whereas noninventive compounds bring a pronounced increase in viscosity and therefore make processing more difficult.