Production of polyurethane foams comprising polyolefin-based polyols

Abstract

Described are a method of producing polyurethane foam comprising polyolefin-based polyols by using an additive composition comprising at least one ionic surfactant A selected from ionic surfactants of formula A.sup.M.sup.+, where A.sup.=anion selected from the group consisting of alkyl sulphates, aryl sulphates, sulphonates, polyether sulphates, polyether sulphonates, alkyl sulphonates, aryl sulphonates, alkyl carboxylates, aryl carboxylates, saccharinates and polyether phosphates, and M.sup.+=cation, and/or at least one ionic surfactant B selected from a quaternized ammonium compound, and also at least a tertiary amine compound C having a molar mass of at least 150 g/mol, and/or an oxazasilinane D, and also polyurethane foams thus obtained and their use.

Claims

1. A method of producing polyurethane foams having a density of 25.1 kg/m.sup.3 or less, said method comprising: reacting one or more polyol components with one or more isocyanate components, which comprises using at least 15 wt % of polyolefin polyol comprising a unit diene of 4 to 10 carbon atoms wherein the polyolefin polyol comprises from 0.1 to 10% of olefinic double bonding in the polymer backbone, wherein the olefinic double bonding does not include double bonds in any aromatic groups in the polyolefin, based on the total amount of polyol used, in the presence of an additive composition wherein said additive composition is present in an amount from 0.001 to 10 parts by weight of total polyol used, said additive composition comprising a mixture of: a) an ionic surfactant B selected from a quaternized ammonium compound, b) a tertiary amine compound C having a molar mass of at least 150 g/mol wherein from 0.001 to 5 parts by weight of said tertiary amine compound C is used per 100 parts by weight of total polyol used, and c) an oxazasilinane D wherein a mass ratio of the sum total of said at least one tertiary amine compound C to the sum total of said at least one oxazasilinane D from 500:1 to 1:1 wherein the polyurethane foam has a density of 25.1 kg/m.sup.3 or less.

2. The method according to claim 1, wherein said one or more polyol components comprise at least 25 wt % of said polyolefin polyol, based on the total amount of polyol used, wherein a mass ratio of the sum total of said at least one tertiary amine compound C to the sum total of said at least one oxazasilinane D from 50:1 to 10:1 and wherein the polyurethane foam has a density of 24.2 kg/m.sup.3 or less.

3. The method according to claim 1, wherein said polyolefin polyol is selected from the group consisting of polybutadiene polyol, hydrogenated polybutadiene polyol, polyisoprene polyol and mixtures thereof and wherein the polyurethane foam has a density of 24.2 kg/m.sup.3 or less.

4. The method according to claim 1, wherein from 0.02 to 3 parts by weight of said tertiary amine compound C is used per 100 parts by weight of total polyol used and wherein the polyurethane foam has a density of 24.2 kg/m.sup.3 or less.

5. The method according to claim 1, wherein said at least one oxazasilinane D is present in said additive composition, said at least one oxazasilinane D is a 2,2,4-trimethyl-1,4,2-oxazasilinane of formula (III) ##STR00014## and wherein the polyurethane foam has a density of 24.2 kg/m.sup.3 or less.

6. The method according to claim 5, wherein a mass ratio of the sum total of said at least one tertiary amine compound C to the sum total of said at least one oxazasilinane D from 200:1 to 5:1.

7. The method according to claim 1, wherein said additive composition comprises by way of ionic surfactant B at least an imidazolium compound of formula (IV), ##STR00015## where R represents alike or different, saturated or unsaturated, optionally alkoxylated hydrocarbon moieties of 1 to 30 carbon atoms and wherein the polyurethane foam has a density of 24.2 kg/m.sup.3 or less.

8. A method according to claim 1, wherein said additive composition is present in an amount from 0.2 to 5 parts by weight of total polyol used and wherein the polyurethane foam has a density of 24.2 kg/m.sup.3 or less.

9. The method according to claim 1, wherein said additive composition comprises (i) a tertiary amine compound C, at least a compound of formula (V) ##STR00016## where R.sup.4 is a saturated or unsaturated hydrocarbon moieties of 5 to 30, R.sup.5 is a divalent alkyl of 2 or 3 carbon atoms, R.sup.6 is a alike or different, alkyl moieties of 1 to 3 carbon atoms (ii) as said at least one ionic surfactant B, an imidazolium compound of formula (IV), ##STR00017## where R represents alike or different, saturated or unsaturated, optionally alkoxylated hydrocarbon moieties of 1 to 30 carbon atoms, and (iii) as said at least one oxazasilinane a 2,2,4-trimethyl-1,4,2-oxazasilinane of formula (III) ##STR00018## wherein one polyol component used is a polyol mixture comprising at least 25 wt % of said polyolefin polyol, based on the total amount of polyol used.

10. The method according to claim 1, wherein said one or more polyol components comprise at least 50 wt % of said polyolefin polyol, based on the total amount of polyol used and wherein the polyurethane foam has a density of 24.2 kg/m.sup.3.

11. The method according to claim 1, wherein said one or more polyol components comprise at least 75 wt % of said polyolefin polyol, based on the total amount of polyol used and wherein the polyurethane foam has a density of 24.2 kg/m.sup.3 or less.

12. The method according to claim 5, wherein a mass ratio of the sum total of said at least one tertiary amine compound C to the sum total of said at least one oxazasilinane D from 50:1 to 10:1.

13. A method according to claim 1, wherein said additive composition is present in an amount from 0.02 to 5 parts by weight of total polyol used and wherein no fatty acid ester sulphate is used in the method of claim 1.

Description

EXAMPLES

(1) Producing the Polyurethane Foams

(2) The polyurethane foams were each produced using 400 g of polyol; the other formulation constituents were arithmetically converted appropriately. For example, 1.0 part of a component meant 1 g of this substance per 100 g of polyol.

(3) For foaming, the polyol, water, catalyst (amine(s) and/or the tin compound), stabilizer and inventive additive composition were thoroughly mixed by stirring. Following addition of the isocyanate, the mixture was stirred at 3000 rpm using a stirrer for 7 sec and was poured into a paper-lined wooden box (base area 27 cm27 cm). Flexible polyurethane foams were obtained and subjected to the performance tests described hereinbelow.

(4) Two recipes were used to demonstrate the present invention for flexible polyurethane foaming. Both recipes are water blown and free rise (foams can rise unhinderedly, i.e. not a moulded foam). The water quantity was chosen as 4.0 parts per 100 parts of polyol mixture. A density of about 25 kg/m.sup.3 will be expected to result from this water quantity. Therefore, the formulation is as regards density and water quantity typical of flexible polyurethane foam grades currently being used in the industry for cushioning or mattress applicationsapart from the fact that the industry has hitherto not used polybutadiene polyol for this purpose. The two recipes differ as regards the amount of polybutadiene polyol employed. Recipe 1 (table 1) uses exclusively polybutadiene polyol. Recipe 2 (table 2) employs a 1:1 mixture of polybutadiene polyol and standard polyether polyol. Additionally present, besides the polyol components and the water, are catalysts (tin catalyst, 2 amine catalysts), a silicone-based foam stabilizer (TEGOSTAB BF 2370) and tolylene diisocyanate. Various additives were admixed that their effect on foam production may be investigated. A reference foam without further additives was in either case produced first.

(5) TABLE-US-00001 TABLE 1 Recipe 1 (Particulars in parts by mass) 100 parts Poly bd R-45HTLO polybutadiene polyol (Cray Valley, France)*.sup.1 4.0 parts water in total (in the case of additives having a water content, the amount of water added has to be correspondingly reduced) 1.0 part TEGOSTAB BF 2370 silicone-based foam stabilizer (Evonik Goldschmidt GmbH) 0.2 part TEGOAMIN 33 (Evonik Goldschmidt GmbH): solution of 33% of triethylenediamine in dipropylene glycol 0.2 part TEGOAMIN DMEA (Evonik Goldschmidt GmbH): N,N-dimethylethanolamine 0.6 part KOSMOS 29 (Evonik Goldschmidt GmbH): tin octoate varies inventive additive 48.0 isocyanate (T80 tolylene diisocyanate) (80% 2,4-isomer, 20% 2,6-isomer) (Bayer Material Science AG) <105> *.sup.1= polybutadiene polyol having an OH number of 47.1 mg KOH/g and an average OH functionality of 2.5 per molecule, molar mass 2800 g/mol.

(6) TABLE-US-00002 TABLE 2 Recipe 2 (Particulars in parts by mass) 50 parts Poly bd R-45HTLO polybutadiene polyol (Cray Valley, France)*.sup.1 50 parts standard polyether polyol VORANOL CP 3322 (Dow Chemical)*.sup.2 4.0 parts water in total (in the case of additives having a water content, the amount of water added has to be correspondingly reduced) 1.0 part TEGOSTAB BF 2370 silicone-based foam stabilizer (Evonik Goldschmidt GmbH) 0.2 part TEGOAMIN 33 (Evonik Goldschmidt GmbH): solution of 33% of triethylenediamine in dipropylene glycol 0.2 part TEGOAMIN DMEA (Evonik Goldschmidt GmbH): N,N- dimethylethanolamine 0.6 part KOSMOS 29 (Evonik Goldschmidt GmbH): tin octoate varies inventive additive 48.0 isocyanate (T80 tolylene diisocyanate) (80% 2,4-isomer, 20% 2,6-isomer) (Bayer Material Science AG) <105> *.sup.1= polybutadiene polyol having an OH number of 47.1 mg KOH/g and an average OH functionality of 2.5 per molecule, molar mass 2800 g/mol. *.sup.2= Voranol CP 3322, obtainable from Dow Chemical, a polyether triol of OH number 47 mg KOH/g.
Ionic Surfactants Used:
surfactant 1: MARLON AM 80 (benzenesulphonic acid, C10-13 alkyl derivatives, sodium salts, available from Sasol), water content: 8 wt %
surfactant 2: petroleum sulphonate (Additiv Chemie Luers GmbH & Co Kg.)
surfactant 3: REWOQUAT W 3690 (Evonik Goldschmidt GmbH, imidazolium compounds, 2-(C17- and C17-unsaturated alkyl)-1-[2-(C18- and C18-unsaturated amido)ethyl]-4,5-dihydro-1-methyl-, methylsulphates >=75 to <=77%; 2-propanol, >=23 to <=25%)
Tertiary Amine Used:
Amine C: Tego Amid D5040 (Evonik Goldschmidt GmbH), coco fatty acid amide amine, static surface tension 0.5% in water: 27.7 mN/m.
Oxazasilinane Used:
2,2,4-trimethyl-1,4,2-oxazasilinane (Apollo Scientific Ltd.), water content: anhydrous
Performance Tests

(7) The foams produced were assessed on the following physical properties: a) Foam settling at the end of the rise time: Settling or conversely post-rise is obtained from the difference in foam height after direct blow-off and after 3 min after blow-off of the foam. Foam height here is measured using a needle secured to a centimeter scale, on the peak in the middle of the foam top surface. A negative value here describes the settling of the foam after the blow-off, while a positive value correspondingly describes the post-rise of the foam. b) Foam height is the height after 3 minutes of the free-rise foam formed. c) Full rise time The time between the end of mixing the reaction components and the blow-off of the polyurethane foam. d) Density Determined as described in ASTM D 3574-08 under test A by measuring the core density. e) The air permeability of the foam has been measured as back pressure. The measured back pressure was reported in mm of water column, with the lower values characterizing the more open foam. The values were measured in the range from 0 to 300 mm. f) Number of cells per cm (cell count): it is determined along a line by counting the cells through a magnifying glass and averaging 3 measurements.
Results of Foaming Trials:

(8) Results of the performance tests for the various recipes and additives used are reported in tables 3 and 4.

(9) TABLE-US-00003 TABLE 3 Foaming results on using 100 wt % of polybutadiene polyol based on total polyol quantity (produced as per recipe 1 in table 1) Usage Full rise Foam Back pressure level time Settling height of water column Cell count Experiment Additive [pphp] [s] [cm] [cm] Density [kg/m.sup.3] [mm] [1/cm] Comment 1 no additive 132 <5 cm collapse 2 Marlon AM 80 0.84 147 <5 cm collapse 3 petroleum sulphonate 0.84 153 <5 cm collapse 4 Rewoquat W 3690 0.84 168 <5 cm collapse 5 Tegoamid D5040 0.84 121 8.0 16.5 inhomogeneous, * large cracks partial collapse, strong and voids* densifications densification in lower half* 6 Oxazasilinane 0.025 103 <5 cm collapse 7 Mixture of Rewoquat W 1.7 145 0.1 27.5 24.2 40 15 open, fine and 3690, Tegoamid D5040, homogeneous oxazasilinane (49.25%, cellular structure 49.25%, 1.50%) (inventive additive composition) *= It is not sensible to determine the physical parameters of density, air permeability and cell count in the case of an inhomogeneous distribution across the test specimen. A partial collapse of the nascent flexible polyurethane foam results in severe densifications in the bottom zone. [pphp] = parts by weight per 100 parts by weight of polyol

(10) TABLE-US-00004 TABLE 4 Foaming results on using 50 wt % of polybutadiene polyol based on total polyol quantity (produced as per recipe 2 in table 2) Back Full rise pressure of Usage level time Settling Foam water column Cell count Experiment Additive [pphp] [s] [cm] height [cm] Density [kg/m.sup.3] [mm] [1/cm] Comment 8 no additive 136 <5 cm collapse 9 Marlon AM 80 0.84 151 <5 cm collapse 10 petroleum 0.84 150 <5 cm collapse sulphonate 11 Rewoquat W 3690 0.84 155 <5 cm collapse 12 Tegoamid D5040 0.84 125 <5 cm collapse 13 Oxazasilinane 0.025 111 <5 cm collapse 14 Mixture of 1.7 137 0.5 26.8 25.1 25 10 open, fine and Rewoquat, homogeneous Tegoamid, cellular oxazasilinane structure (49.25%, 49.25%, 1.50%) (inventive additive composition) [pphp]= parts by weight per 100 parts by weight of polyol *= It is not sensible to determine the physical parameters of density, air permeability and cell count in the case of an inhomogeneous distribution across the test specimen. A partial collapse of the nascent polyurethane foam results in severe densifications in the bottom zone.

(11) It transpired with both series of experiments that foaming the polybutadiene polyol without the admixture of suitable additives leads to instabilities and collapse (experiments 1 and 8). The addition of two commercially available sulphonates does nothing to change the instability and there continued to be an observable collapse (experiments 2 and 3 and 9 and 10). The same was observed on admixture of Rewoquat (experiments 4 and 11). Using Tegoamid D 5040 resulted in partial collapse in the experiment with 100% of polybutadiene polyol (experiment 5). Foam height in the end is significantly lower than the expected foam height (16.5 cm versus about 28 cm) and the foam formed exhibits severe densifications in its lower region. Collapse was observed when using a mixture of polyether polyol and polybutadiene polyol (experiment 12). The sole admixture of an oxazasilinane did lead to a significant shortening in the full rise time, but did not result in the formation of a stable foam (experiments 6 and 13).

(12) Surprisingly, both recipes give a stable foam having merely minimal settling on employing the additives which are to be employed according to the present invention (experiments 7 and 14). The physical properties are homogeneous across the foam body, so it was sensible to determine these properties. The density of the flexible polyurethane foam formed at 24.2 kg/m.sup.3 and 25.1 kg/m.sup.3 is in the desired range. The full rise time at 145 s and 137 s is in an interval which is also typical for the manufacture of industrial flexible polyurethane foams based on polyether polyol. The flexible polyurethane foam formed in experiments 7 and 14 is open cell (back pressure <100 mm of water column) and has a cell fineness (experiment 7: 15 cells/cm, experiment 14: 10 cells/cm) as also encountered with industrial flexible polyurethane foams based on polyether polyol.