PRODUCTION OF POLYURETHANE FOAM

Abstract

Compositions suitable for production of polyurethane foams, comprising at least one OH-functional compound (OHC) obtainable by the partial or complete hydrogenation of ketone-aldehyde resins, wherein the OH-functional compound contains at least one structural element of the formula (1a) and optionally of the formulae (1b) and/or (1c),

##STR00001##

with R=aromatic with 6-14 carbon atoms, (cyclo)aliphatic with 1-12 carbon atoms, R.sup.1=H, CH.sub.2OH, R.sup.2=H, or a radical of the formula (CH.sub.2CH(R)O).sub.yH where R is hydrogen, methyl, ethyl or phenyl and y=1 to 50, k=2 to 15, preferably 3 to 12, more preferably 4 to 11, m=0 to 13, preferably 0 to 9, l=0 to 2,
where the sum of k+l+m is from 5 to 15, preferably from 5 to 12, and k>m, are described.

Claims

1. A composition for production of polyurethane foam and rigid polyurethane foam, the composition comprising at least one isocyanate component, a polyol component, a catalyst which catalyses the formation of a urethane or isocyanurate bond, and a blowing agent, wherein the composition additionally includes at least one OH-functional compound (OHC) obtainable by the partial or complete hydrogenation of ketone-aldehyde resins, wherein this OH-functional compound contains at least one structural element of the formula (1a) and of the formulae (1b) and/or (1c), ##STR00006## with R is aromatic hydrocarbyl radical having 6-14 carbon atoms or (cyclo)aliphatic hydrocarbyl radical having 1-12 carbon atoms, where the hydrocarbyl radicals may optionally be substituted, R.sup.1 is H, or CH.sub.2OH, R.sup.2 is H, or a radical of the formula (CH.sub.2CH(R)O).sub.yH where R is hydrogen, methyl, ethyl or phenyl and y=1 to 50, k is from 2 to 15, m is from 0 to 13, l is from 0 to 2, where the sum of k+l+m is from 5 to 15, and k>m, with the proviso that at least 90 parts by weight of the polyols present have an OH number of greater than 100, based on 100 parts by weight of polyol components.

2. The composition according to claim 1, wherein the OH-functional compound (OHC) is present in a total proportion by mass of from 0.5 to 100.0 parts, based on 100 parts polyol component.

3. The composition according to claim 1, wherein the OH-functional compound (OHC) is present in a total proportion by mass of at least 30 parts, based on 100 parts polyol component.

4. The composition according to claim 1, wherein polyester polyols are additionally present.

5. A process for producing polyurethane foam by reacting one or more polyol components with one or more isocyanate components, wherein the reaction is effected in the presence of at least one OH-functional compound (OHC) obtainable by the partial or full hydrogenation of ketone-aldehyde resins, where this OH-functional compound contains at least one structural element of the formula (1a) and optionally of the formulae (1b) and/or (1c) ##STR00007## with R is aromatic hydrocarbyl radical having 6-14 carbon atoms or (cyclo)aliphatic hydrocarbyl radical having 1-12 carbon atoms, where the hydrocarbyl radicals may optionally be substituted, R.sup.1 is H, or CH.sub.2OH, R.sup.2 is H, or a radical of the formula (CH.sub.2CH(R)O).sub.yH where R is hydrogen, methyl, ethyl or phenyl and y=1 to 50, k is from 2 to 15, m is from 0 to 13, l is from 0 to 2, where the sum of k+l+m is from 5 to 15, and k>m, with the proviso that at least 90 parts by weight of the polyols used, have an OH number of greater than 100, based on 100 parts by weight of polyol components.

6. The polyurethane foam obtainable by a process according to claim 5.

7. The polyurethane foam according to claim 6, wherein the density is from 5 to 750 kg/m.sup.3.

8. The polyurethane foam according to claim 6, wherein the closed-cell content is >80%, the closed-cell content being determined in accordance with DIN ISO 4590.

9. The polyurethane foam according to claim 6, wherein it includes 0.1% to 60% by mass, of OH-functional compounds (OHC).

10-15. (canceled)

16. The composition according to claim 1, wherein k is from 3 to 12, m is from 0 to 9, where the sum of k+l+m is from 5 to 12, and k>m, and wherein at least 90 parts by weight of the polyols present have an OH number of greater than 150, based on 100 parts by weight of polyol components.

17. The composition according to claim 1, wherein k is from 4 to 11, and wherein at least 90 parts by weight of the polyols present have an OH number of greater than 200, based on 100 parts by weight of polyol components.

18. The composition according to claim 1, wherein the OH-functional compound (OHC) is present in a total proportion by mass of 1 to 80 parts, based on 100 parts polyol component.

19. The composition according to claim 1, wherein the OH-functional compound (OHC) is present in a total proportion by mass of at least 40 parts, based on 100 parts polyol component.

20. The polyurethane foam according to claim 6, wherein the density is from 5 to 350 kg/m.sup.3.

21. The polyurethane foam according to claim 6, wherein the closed-cell content is greater than 90%, the closed-cell content being determined in accordance with DIN ISO 4590.

22. The polyurethane foam according to claim 6, wherein it includes from 0.5% to 40% by mass of OH-functional compounds (OHC).

23. The polyurethane foam according to claim 6, wherein the density is from 5 to 350 kg/m.sup.3.

24. The polyurethane foam according to claim 6, wherein the closed-cell content is greater than 90%, the closed-cell content being determined in accordance with DIN ISO 4590.

25. The polyurethane foam according to claim 6, wherein it includes from 1% to 30% by mass of OH-functional compounds (OHC).

26. The polyurethane foam according to claim 7, wherein it includes from 1% to 30% by mass of OH-functional compounds (OHC).

Description

EXAMPLES

Materials Used:

[0100] OH-functional compounds (OHCs) of the invention were prepared by the processes described in DE 102007018812. OHC-1 corresponds to the carbonyl-hydrogenated ketone-aldehyde resin no. II described in DE 102007018812.

[0101] 1200 g of acetophenone, 220 g of methanol, 0.3 g of benzyltributylammonium chloride and 360 g of a 30% aqueous formaldehyde solution were initially charged and homogenized while stirring. Then 32 g of a 25% aqueous sodium hydroxide solution were added while stirring. At 80 to 85 C., 655 g of a 30% aqueous formaldehyde solution were then added while stirring over 90 min. The stirrer was switched off after stirring at reflux temperature for 5 h and the aqueous phase was separated from the resin phase. The crude product was washed with dilute acetic acid until a molten sample of the resin appears clear. Then the resin was dried by distillation. 1270 g of a pale yellowish resin were obtained. The resin was clear and brittle and had a melting point of 72 C. The Gardner colour number was 0.8 (50% in ethyl acetate). The formaldehyde content was 35 ppm. This product is referred to as base resin.

[0102] 300 g of the base resin were dissolved in 700 g of tetrahydrofuran (water content about 7%). Then the hydrogenation was effected at 260 bar and 120 C. in an autoclave (from Parr) with a catalyst basket filled with 100 ml of a commercial Ru catalyst (3% Ru on alumina). After 20 h, the reaction mixture was let out of the reactor via a filter.

[0103] The reaction mixture was freed of the solvent under reduced pressure. This resulted in the inventive OH-functional compound OHC-1.

[0104] OHC-2 to OHC-5 were likewise prepared by oxyalkylation in accordance with DE102007018812. The following amounts of ethylene oxide (EO) or propylene oxide (PO) per OH function were added onto OHC-1:

OHC-2: OHC-1+3EO

OHC-3: OHC-1+5EO

OHC-4: OHC-1+3PO

OHC-5: OHC-1+5PO

[0105] The compounds of the invention had the following OH numbers (in mg KOH/g):

OHC-1: OH number=325
OHC-2: OH number=225
OHC-3: OH number=188
OHC-4: OH number=158
OHC-5: OH number=127

[0106] The Si surfactants used were the following materials:

Siloxane 1: Polyether siloxane, as described in EP 1544235 A1 in Example 14.
Siloxane 2: Polyether siloxane, as described in US 2015/0057384 in Example 2.
PS 3152: polyester polyol from Stepan
PS 2352: polyester polyol from Stepan
PS 2412: polyester polyol from Stepan
R 471: Daltolac R 471, polyether polyol from Huntsman
R 251: Daltolac R 251, polyether polyol from Huntsman
Voranol RN 490: polyether polyol from Dow
Terate 203: polyester polyol from Invista
TCPP: tris(2-chloroisopropyl) phosphate from Fyrol
Kosmos 75 from Evonik Industries AG, catalyst based on potassium octoate
Kosmos 19 from Evonik Industries AG, dibutyltin dilaurate
PMDETA: TEGOAMIN PMDETA from Evonik Industries AG, amine catalyst
DMCHA: TEGOAMIN DMCHA from Evonik Industries AG, amine catalyst
MDI (44V20): Desmodur 44V20L from Bayer Materialscience, diphenylmethane 4,4-diisocyanate (MDI) with isomeric and higher-functionality homologues
Stepanpol PS-3152: diethylene glycol phthalate polyester polyol, Stepan Company

Foam Density Determination

[0107] To determine the foam density, specimens having the dimensions of 101010 cm were cut out of the foams. These were weighed in order to determine the masses. The volume was determined by the measurement of water displacement, by immersing the samples in a beaker containing water and measuring the increase in weight.

[0108] In this way, the volume of the specimens was ascertained. By repeatedly measuring the volume of the specimens after curing times of different length, the shrinkage was thus determined.

Examples: Production of PU Foams

[0109] In the case of use of inventive compounds of the formula (OHC) which were either in solid form or had a very high viscosity, these were dissolved in the flame retardant and used in this form.

[0110] The foams were produced by manual mixing. For this purpose, the inventive compounds, polyols, flame retardant, catalysts, water, conventional or inventive foam stabilizer and blowing agent were weighed into a beaker and mixed by means of a disc stirrer (6 cm in diameter) at 1000 rpm for 30 s. The blowing agent quantity which had evaporated during the mixing operation was determined by reweighing and replenished. Subsequently, the isocyanate (MDI) was added, and the reaction mixture was stirred with the stirrer described at 3000 rpm for 5 s. In the case of pour-in-place foaming, foaming was effected in the beaker itself; otherwise, the mixture was transferred into a paper-lined box of base area 2714 cm.

[0111] In the case of flow applications, for example refrigerator systems, the mixture was introduced immediately into an aluminium mould of dimensions 145 cm14.5 cm3.5 cm which had been heated to 45 C. The amount of foam formulation used was determined such that it was 15% above the minimum amount necessary to fill the mould. According to the method of analysis, the specimens were cut out of the foam blocks after only 2 hours, or the samples were not taken until after one day.

[0112] In the case of the beaker foams, the rise behaviour, i.e. the outward shape, the surface of the foam and, using a cut surface within the upper part of the foam, the degree of internal defects and the pore structure were assessed visually on a scale from 1 to 10, with 10 representing a faultless foam and 1 a foam having an extremely high level of defects.

[0113] The compressive strengths of the foams were measured on cubic test specimens having an edge length of 5 cm in accordance with DIN 53421 up to a compression of 10% (the maximum compressive stress occurring in this measuring range is reported).

[0114] Tables 2, 3 and 4 summarize results with free rise foams (box).

[0115] In these tables, the examples labelled -comp. are the noninventive comparative examples. The following are summarized here: the recipes used to produce the foams, the weights of the specimens (with dimensions of 101010 cm) and the volumes of specimens and hence the shrinkage after various periods of time.

TABLE-US-00003 TABLE 2 Example Formulation 1-comp. 1 2-comp. 2 3-comp. 3 PS 2352 100 94 100 94 100 94 OHC-1 0 6 0 6 0 6 Kosmos 75 3 3 3 3 3 3 PMDETA 0.5 0.5 0.5 0.5 0.5 0.5 Siloxane 2 2 2 2 2 2 2 TCPP 20 20 20 20 20 20 Water 1 1 1 1 1 1 Cyclopentane 13 13 14 14 15 15 MDI (44V20) 180 180 180 180 180 180 Specimen 31.5 31.5 31.3 30.7 29.3 29.7 weight in g Volume in 981.1 981.2 980.0 978.9 972.7 975.4 ml after 2 h Density in 32.1 32.1 31.9 31.4 30.1 30.4 kg/m.sup.3 Volume in 957.4 966.4 941.6 957.7 931.2 947.7 ml after 24 h 24 h 2.42 1.51 3.92 2.17 4.27 2.84 shrinkage/% Volume in 929.3 947.5 903.8 938.3 880.3 913.5 ml after 6 d 6 d 5.28 3.43 7.78 4.15 9.50 6.35 shrinkage/%

[0116] In all three examples, the foams which have been produced with the OH-functional compounds of the invention have lower shrinkage than the comparative examples. This was the case both after 24 hours and after 6 days.

TABLE-US-00004 TABLE 3 Purely water-blown systems Example Formulation 4-comp. 4 Daltolac R 471 30 30 Daltolac R 251 70 64 OHC-1 6 DMCHA 1.5 1.5 Siloxane 1 2 2 TCPP 20 20 Water 5 5 MDI (44V20) 190 190 Specimen weight in g 32.0 31.5 Volume in ml after 2 h 971 963 Density in kg/m.sup.3 32.9 33.1 Volume in ml after 24 h 954 949 24 h shrinkage/% 1.8 1.5 Volume in ml after 6 d 940 937 6 d shrinkage/% 3.3 2.7

[0117] In Example 4, a purely water-blown formulation was examined. In this case, the foam which has been produced with OH-functional compounds of the invention has lower shrinkage than the comparative example. This was the case both after 24 hours and after 6 days.

[0118] Table 4 summarizes the results with the alkoxylated compounds OHC-2 to OHC-5.

TABLE-US-00005 TABLE 4 Example Formulation 5-comp. 5a 5b 5c 5d PS 2352 100 95 95 95 95 OHC-2 5 OHC-3 5 OHC-4 5 OHC-5 5 Kosmos 75 3 3 3 3 3 PMDETA 0.5 0.5 0.5 0.5 0.5 Siloxane 2 2 2 2 2 2 TCPP 10 10 10 10 10 Water 1 1 1 1 1 Cyclopentane 15 15 15 15 15 MDI (44V20) 180 180 180 180 180 Specimen weight in g 30.4 29.2 29.4 30.4 29.6 Volume in ml after 2 h 970.3 969.0 973.7 963.9 972.3 Density in kg/m.sup.3 31.4 30.1 30.2 31.5 30.4 Volume in ml after 24 h 935.4 943.5 952.26 942.4 962.8 24 h shrinkage/% 3.6 2.6 2.2 2.2 1.0

[0119] In the case of the alkoxylated compounds too, it is already apparent after 24 hours that the foam formulations of the invention have a reduced tendency to shrinkage.

Examples for Improvement of Compressive Strength

[0120] For the foaming operations summarized in Table 5, the raw materials were heated to 40 C. in order that the viscosities did not become too high and good mixing of the components could be assured. Here, the compressive strengths were determined in the evaluation.

TABLE-US-00006 TABLE 5 Example Formulation 6. 6-comp. 7 7-comp. 8 8-comp. PS 2412 70 100 70 100 PS 3152 70 100 0 OHC-1 30 30 30 Kosmos 75 1.5 1.5 1.5 1.5 1.5 1.5 PMDETA 0.2 0.2 0.2 0.2 0.2 0.2 Siloxane 1 2 2 2 2 2 2 Water 2 2 2 2 1.5 1.5 MDI (44V20) 200 200 200 200 200 200 <Index> 209 223 184 186 227 244 Density in kg/m.sup.3 44.7 43.6 45.5 46.9 48.9 49.8 Compressive strength in kPa vertical 266 214 263 213 402 230 horizontal 176 140 205 145 189 153

[0121] Examples 6 to 8 show that, in the case of use of the compounds of the invention as compared with commercially available polyols having comparable OH numbers, higher compressive strengths were achievable in the foams without any need to increase the densities. The values measured for the inventive examples were higher throughout both in the direction of rise (vertical) and transverse to the direction of rise (horizontal) than in the noninventive examples. It is of particular interest here that the elevated foam hardness was achievable without an increase in the index or the amount of isocyanate.

Examples of Fire Characteristics (B2 Test)

[0122] For the foaming operations summarized in Table 6, the raw materials were heated to 40 C. in order that the viscosities did not become too high and good mixing of the components could be assured. Here, the fire properties for B2 classification (DIN 4102) by means of flame height were determined in the evaluation.

TABLE-US-00007 TABLE 6 Example Formulation 9 10 11 Datlolac 471 10 PEG 400 60 OHC-1 27 30 40 TCPP 63 70 Kosmos 75 1.5 1.5 1.5 DMCHA 0.6 0.6 0.6 Siloxane 1 2 2 2 Water 1 1 1 MDI (44V20) 180 150 220 <Index> 366 374 250 Flame height in mm 80 75 130

[0123] Examples 9 to 11 show that the compounds of the invention are suitable for production of foams having very good fire properties. Thus, it is possible in Examples 9 and 10 to work with very high amounts of flame retardant, which leads to very unstable formulations with conventional polyols. In Example 11, it was possible to completely dispense with flame retardants and nevertheless achieve a flame height of less than 150 mm.

Examples in Flow Applications for Improvement of Compressive Strength

[0124] The foaming operations summarized in Table 7 were conducted in the above-described aluminium mouldcalled the Bosch mouldin order to simulate the situation with flow stress in refrigerator production. The evaluations and measurements were effected after 24 hours.

TABLE-US-00008 TABLE 7 Example Formulation 12-comp. 12a 12b Daltolac R 471 100 97.5 95 OHC-1 2.5 5 TEGOAMIN DMCHA 1.5 1.5 1.5 Siloxane 1 2 2 2 cyclo-Pentane 13 13 13 Water 1.8 1.8 1.8 MDI (44V20) 170 170 170 <Index> 122 122 122 value in mW/m .Math. K 23.6 23.5 23.7 Compressive strength in kPa vertical 184 195 220

[0125] Here too, it was found that the compressive strengths, i.e. the mechanical properties of the foams, can be improved with the compounds of the invention without having to accept losses of quality in the lambda values.

Examples with Inventive Compounds as Foam Stabilizer

[0126] The rigid PUR foam system specified in Table 8 was used for the pour-in-place applications.

TABLE-US-00009 TABLE 8 Pour-in-place formulation Component Proportion by weight Voranol RN 490 70 parts Terate 203 20 parts Stepanpol PS 3152 10 parts TCPP 6 parts N,N-Dimethylethanolamine 0.35 part DMCHA 1.6 parts Kosmos 19 0.07 Water 0.33 part Foam Stabilizer 1.3 parts Cyclopentane 21 parts Desmodur 44V20L 151 parts

[0127] The results of the pour-in-place applications are reported in Table 9.

TABLE-US-00010 TABLE 9 Results for pour-in-place Internal Pore Rise defects structure charac- Ex. Stabilizer (1-10) (1-10) teristics Surface 13a OHC-2 6 5 5 5 13b OHC-3 6 6 5 5 13- Siloxane 1 8 7 6 7 comp.

[0128] Examples 13a and 13b show that the inventive compounds can be used as stabilizing component in the production of PU foams. Comparably good foams to those obtained with Si-containing stabilizers in Example 13-comp. are obtained.