Patent Application
20210139634
It is known from the prior art that polyurethane foams can emit aldehydes, these aldehyde emissions generally being unwanted. These emissions are detected for example in measurements according to VDA 275 (flask method, 60° C.) or else according to VDA 276 (emissions chamber test, 65° C.).
WO2015082316 describes that certain cyanoacetamides can be suitable for reducing the emissions of formaldehyde from foams. Furthermore, WO2015082316 describes that certain esters of cyanoacetic acid and of 3-oxocarboxylic acids can be suitable therefor.
JP 2004129926 describes a polymerized acrylate resin (largely free from unsaturated double bonds) for absorption of formaldehyde. This employs the known activity of acetoacetates (WO2015082316) which the inventors have attached to the acrylate resin.
DE 199 19 826 describes the use of certain additives, for example α,β-unsaturated carboxylic acid derivatives, in the production of polyurethane foams for reducing the content of primary aromatic amines. The use of such compounds in the production of polyurethanes for reducing the aldehyde emission of the resulting polyurethanes is not disclosed.
The present invention has for its object to provide polyurethanes, preferably polyurethane foams, exhibiting even lower aldehyde emission (formaldehyde and acetaldehyde) than polyurethanes/polyurethane foams of the prior art.
This object is achieved through the use of isocyanate-reactive acrylic esters and amides and derivatives thereof in the production of the polyurethanes.
The present invention accordingly provides for the use of α,β-unsaturated carboxylic esters and/or amides in processes for producing polyurethanes, preferably polyurethane foams, for reducing the aldehyde emission of the resulting polyurethanes/polyurethane foams.
Preferred in accordance with the present invention is the use
R1R2C═CR3—C(O)—O—R4 (I.),
R5R6C═CR7—C(O)—O—R8—O—(O)C—R9C═CR10R11 (II.),
R12R13C═CR14—C(O)—O—(O)C—R14C═CR13R12 (III.) and
R15R16C═CR17—C(O)—NR18—R19 (IV.),
Should there be compounds which conform both to the definition of component (ii) and to the definition of component (II) these compounds shall be assigned to the component (ii).
Particularly preferred in accordance with the present invention is the use
R1R2C═CR3—C(O)—O—R4 (I.),
R5R6C═CR7—C(O)—O—R8—O—(O)C—R9C═CR10R11 (II.),
R12R13C═CR14—C(O)—O—(O)C—R14C═CR13R12 (III.) and
R15R16C═CR17—C(O)—NR18—R19 (IV.),
The usage amount of the inventive component B based on 1 kg of the components A1 and C is 1 to 100 g, preferably 5 to 50 g (the value of 1 kg relates to the sum of A1 and C).
Component B is subjected to non-vinylic polymerization.
Very particularly preferred in accordance with the present invention (alternative I) is the use
R1R2C═CR3—C(O)—O—R4 (I.),
R5R6C═CR7—C(O)—O—R8—O—(O)C—R9C═CR10R11 (II.),
R12R13C═CR14—C(O)—O—(O)C—R14C═CR13R12 (III.) and
R15R16C═CR17—C(O)—NR18—R19 (IV.),
Likewise very particularly preferred (alternative II) is the use
R1R2C═CR3—C(O)—O—R4 (I.),
R5R6C═CR7—C(O)—O—R8—O—(O)C—R9C═CR10R11 (II.),
R12R13C═CR14—C(O)—O—(O)C—R14C═CR13R12 (III.) and
R15R16C═CR17—C(O)—NR18—R19 (IV.),
The present invention further provides a process for producing polyurethanes, preferably polyurethane foams, by reaction of compounds containing isocyanate-reactive hydrogen atoms with di- and/or polyisocyanates in the presence of α,β-unsaturated carboxamides.
Preferred in accordance with the present invention is a process for producing polyurethanes, preferably polyurethane foams, by reaction of compounds containing isocyanate-reactive hydrogen atoms with di- and/or polyisocyanates in the presence of one or more compounds of the formula
R15R16C═CR17—C(O)—NR18—R19 (IV.),
The present invention also provides the polyurethanes/polyurethane foams obtainable by the described process.
The present invention in particular provides a process for producing polyurethane foams in which a component A containing
R15R16C═CR17—C(O)—NR18—R19 (IV.),
The usage amount of the inventive component B based on 1 kg of the components A1 and C is 1 to 100 g, preferably 5 to 50 g (the value of 1 kg relates to the sum of A1 and C.
Very particularly preferred (alternative I) is a process for producing polyurethane foams in which a component A containing
R15R16C═CR17—C(O)—NR18—R19 (IV.),
Likewise very particularly preferred (alternative II) is a process for producing polyurethane foams in which
1 to 100 g per kg of the components A1 and C, preferably 5 to 50 g per kg of the components A1 and C, of a component B which comprises one or more compounds of the formula
R15R16C═CR17—C(O)—NR18—R19 (IV.),
The production of isocyanate-based foams is known per se and described for example in DE-A 1 694 142, DE-A 1 694 215 and DE-A 1 720 768 and also in Kunststoff-Handbuch volume VII, Polyurethane, edited by Vieweg and Höchtlein, Carl Hanser Verlag, Munich 1966, and in the new edition of this book, edited by G. Oertel, Carl Hanser Verlag Munich, Vienna 1993.
The production of the isocyanate-based foams may employ the components more particularly described hereinbelow.
Starting components according to component A1 are compounds having at least two isocyanate-reactive hydrogen atoms having an OH number according to DIN 53240 of ≥15 to <260 mg KOH/g.
This is to be understood as meaning not only amino-containing but also thiol-containing or carboxyl-containing compounds, preferably hydroxyl-containing compounds, in particular compounds containing 2 to 8 hydroxyl groups, specifically those having an OH number according to DIN 53240 of ≥20 to ≤150 mg KOH/g, preferably ≥20 to ≤50 mg KOH/g, very particularly preferably ≥25 to ≤45 mg KOH/g, for example polyethers and polyesters and also polycarbonates and polyesteramides containing at least 2, generally 2 to 8, but preferably 2 to 6, hydroxyl groups, such as are known per se for the production of homogeneous and of cellular polyurethanes and as are described for example in EP-A 0 007 502, pages 8-15. Polyethers and polyesters containing at least two hydroxyl groups are preferred according to the invention. Polyethers containing at least two hydroxyl groups are particularly preferred.
The production of the polyether polyols is carried out by known methods, preferably by base-catalyzed polyaddition of alkylene oxides onto polyfunctional starter compounds containing active hydrogen atoms, for example alcohols or amines. Examples include: ethylene glycol, diethylene glycol, 1,2-propylene glycol, 1,4-butanediol, hexamethylene glycol, bisphenol A, trimethylolpropane, glycerol, pentaerythritol, sorbitol, sucrose, degraded starch, water, methylamine, ethylamine, propylamine, butylamine, aniline, benzylamine, o- and p-toluidine, α,β-naphthylamine, ammonia, ethylenediamine, propylenediamine, 1,4-butylenediamine, 1,2-, 1,3-, 1,4-, 1,5- and/or 1,6-hexamethylenediamine, o-, m-, and p-phenylenediamine, 2,4-, 2,6-tolylenediamine, 2,2′-, 2,4- and 4,4′-diaminodiphenylmethane and diethylenediamine.
Preferably employed as alkylene oxides are ethylene oxide, propylene oxide, butylene oxide and mixtures thereof. The construction of the polyether chains by alkoxylation may be performed with only one monomeric epoxide or else in random or blockwise fashion with two or three different monomeric epoxides.
Processes for producing such polyether polyols are described in “Kunststoffhandbuch, volume 7, Polyurethane”, in “Reaction Polymers” and for example in U.S. Pat. Nos. 1,922,451, 2,674,619, 1,922,459, 3,190,927 and 3,346,557.
The polyaddition may also be carried out with DMC catalysis for example. DMC catalysts and the use thereof for producing polyether polyols are described for example in U.S. Pat. Nos. 3,404,109, 3,829,505, 3,941,849, 5,158,922, 5,470,813, EP-A 700 949, EP-A 743 093, EP-A 761 708, WO-A 97/40086, WO-A 98/16310 and WO-A 00/47649.
In a particularly preferred embodiment component A1 contains at least 30% by weight of at least one polyoxyalkylene polymer consisting of a starter, propylene oxide and optionally ethylene oxide and optionally an end block made of ethylene oxide, wherein the total weight of the end blocks is on average 3-20% by weight, preferably 5-15% by weight, particularly preferably 6-10% by weight, based on the total weight of all polyoxyalkylene polymers.
In addition to the above-described “simple” polyether polyols the process according to the invention may also employ polyether carbonate polyols. Polyether carbonate polyols are obtainable for example by catalytic reaction of ethylene oxide and propylene oxide, optionally further alkylene oxides and carbon dioxide in the presence of H-functional starter substances (see for example EP-A 2046861).
Methods for producing polyester polyols are likewise well known and described for example in the two abovementioned citations (“Kunststoffhandbuch, volume 7, Polyurethane”, “Reaction Polymers”). The polyester polyols are produced inter alia by polycondensation of polyfunctional carboxylic acids or derivatives thereof, for example acid chlorides or anhydrides, with polyfunctional hydroxyl compounds.
Employable polyfunctional carboxylic acids include for example: adipic acid, phthalic acid, isophthalic acid, terephthalic acid, oxalic acid, succinic acid, glutaric acid, azelaic acid, sebacic acid, fumaric acid or maleic acid.
Employable polyfunctional hydroxyl compounds include for example: ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, dipropylene glycol, 1,3-butanediol, 1,4-butanediol, 1,6-hexanediol, 1,12-dodecanediol, neopentyl glycol, trimethylolpropane, triethylolpropane or glycerol.
Production of the polyester polyols may moreover also be effected by ring-opening polymerization of lactones (for example caprolactone) with diols and/or triols as starters.
Also employable in component A1 as hydroxyl-containing compounds of the component A1 are polymer polyols, PUD polyols and PIPA polyols. Polymer polyols are polyols containing proportions of solid polymers produced by free-radical polymerization of suitable monomers such as styrene or acrylonitrile in a base polyol. PUD (polyurea dispersion) polyols are produced for example by in-situ polymerization of an isocyanate or an isocyanate mixture with a diamine and/or hydrazine in a polyol, preferably a polyether polyol. The PUD dispersion is preferably produced by reaction of an isocyanate mixture of 75% to 85% by weight of 2,4-tolylene diisocyanate (2,4-TDI) and 15 to 25% by weight of 2,6-tolylene diisocyanate (2,6-TDI) with a diamine and/or hydrazine in a polyether polyol, preferably a polyether polyol, produced by alkoxylation of a trifunctional starter (for example glycerol and/or trimethylolpropane). Processes for preparing PUD dispersions are described, for example, in U.S. Pat. Nos. 4,089,835 and 4,260,530. PIPA polyols are polyether polyols modified with alkanolamines by polyisocyanate-polyaddition, wherein the polyether polyol has a functionality of from 2.5 to 4 and a hydroxyl number of from ≥3 mg KOH/g to ≤112 mg KOH/g (molecular weight from 500 to 18 000). PIPA polyols are described in detail in GB 2 072 204 A, DE 31 03 757 A1 and U.S. Pat. No. 4,374,209 A.
Optionally employed as component A2 are compounds having at least two isocyanate-reactive hydrogen atoms and an OH number according to DIN 53240 of ≥260 to <4000 mg KOH/g, preferably ≥400 to ≤3000 mg KOH/g, particularly preferably ≥1000 to ≤2000 mg KOH/g.
These include compounds having hydroxyl groups and optionally amino groups, thiol groups or carboxyl groups, preferably compounds containing hydroxyl groups and optionally amino groups.
These compounds have preferably 2 to 8, particularly preferably 2 to 4, isocyanate-reactive hydrogen atoms.
These may be for example low molecular weight diols (for example 1,2-ethanediol, 1,3- or 1,2-propanediol, 1,4-butanediol), triols (for example glycerol, trimethylolpropane), tetraols (for example pentaerythritol), hexaols (for example sorbitol) or amino alcohols (ethanolamine, diethanolamine, triethanolamine).
However, they may also be short chain polyether polyols, polyether carbonate polyols, polyester polyols, polyester carbonate polyols, polythioether polyols, polyacrylate polyols or polycarbonate polyols.
For production of these polymers (reactants, processes) reference is made to what is stated above in connection with component A1.
Further examples of compounds for component A2 are described in EP-A 0 007 502, pages 16-17.
Water and/or physical blowing agents are used as component A3. Physical blowing agents used are, for example, carbon dioxide and/or volatile organic substances.
Optionally used as component A4 are auxiliary and additive substances such as
These auxiliaries and additives for optional additional use are described, for example, in EP-A 0 000 389, pages 18-21. Further examples of auxiliaries and additives for optional additional use in accordance with the invention and details of the manner of use and mode of action of these auxiliaries and additives are described in Kunststoff-Handbuch [Plastics Handbook], volume VII, edited by G. Oertel, Carl-Hanser-Verlag, Munich, 3rd edition, 1993, for example on pages 104-127.
Preferred catalysts are aliphatic tertiary amines (for example trimethylamine, tetramethylbutanediamine), cycloaliphatic tertiary amines (for example 1,4-diaza[2.2.2]bicyclooctane), aliphatic amino ethers (for example dimethylaminoethyl ether and N,N,N-trimethyl-N-hydroxyethylbisaminoethyl ether), cycloaliphatic amino ethers (for example N-ethylmorpholine), aliphatic amidines, cycloaliphatic amidines, urea, derivatives of urea (for example aminoalkylureas; see, for example, EP-A 0 176 013), especially (3-dimethylaminopropylamine)urea), and tin catalysts (for example dibutyltin oxide, dibutyltin dilaurate, tin octoate).
Particularly preferred catalysts are a) urea, derivatives of urea and/or b) the abovementioned amines and amino ethers, characterized in that the amines and amino ethers contain a functional group that undergoes chemical reaction with the isocyanate. Preferably, the functional group is a hydroxyl group, a primary or secondary amino group. These particularly preferred catalysts have the advantage of having greatly reduced migration and emission characteristics. Examples of particularly preferred catalysts include: (3-dimethylaminopropylamine)urea, 1,1′-((3-(dimethylamino)propyl)imino)bis-2-propanol, N-[2-[2-(dimethylamino)ethoxy]ethyl]-N-methyl-1,3-propanediamine and 3-dimethylaminopropylamine.
Excluded from component A4 are free-radical initiators and catalysts which catalyze a vinylic polymerization.
Component B comprises
R1R2C═CR3—C(O)—O—R4 (I.),
R5R6C═CR7—C(O)—O—R8—O—(O)C—R9C═CR10R11 (II.),
R12R13C═CR14—C(O)—O—(O)C—R14C═CR13R12 (III.) and
R15R16C═CR17—C(O)—NR18—R19 (IV.),
It is preferable when in i) the radicals R1 and R2, R4 to R19 independently of one another represent H, a saturated or unsaturated, linear or branched, aliphatic or cycloaliphatic or an aromatic or araliphatic radical having up to 12 carbon atoms which may optionally contain O atoms as heteroatoms and which may optionally be substituted, for example by isocyanate-reactive groups, preferably by OH groups,
R3 represents H,
and
R8 represents a saturated or unsaturated, linear or branched, aliphatic divalent radical having up to 12 carbon atoms which may optionally contain O atoms as heteroatoms and which may optionally be substituted, for example by isocyanate-reactive groups, preferably by OH groups.
It is particularly preferable when in i)
the radical R4 represents —(C1-C12-alkyl); —(C1-C12-alkyl)-Ph or —(C1-C12-alkyl)-X, where X=an NCO-reactive group, preferably an OH group,
the radical R8 represents —(C1-C12-alkyl) or —(C1-C12-alkyl)-X, where X=an NCO-reactive group, preferably an OH group, and
the radicals R18 and/or R19 represent —(C1-C12-alkyl) or —(C1-C12-alkyl)-X, where X=an NCO-reactive group, preferably an OH group.
The following compounds of the components (I) to (IV) and (ii) are recited merely by way of example: benzyl cinnamate, hydroxyethyl acrylate (HEA), hydroxypropyl acrylate (HPA), 3-(acryloyloxy)-2-hydroxypropyl acrylate, (acryloyloxy)-2-hydroxypropyl methacrylate, crotonic anhydride, 1,4-butanediylbis[oxy(2-hydroxy-3,1-propanediyl)] 2-propanoate; ethylacrylamide; hydroxyethylacrylamide; N-methyl-N-(1,3-dihydroxypropyl)acrylamide; N-methyl-N-(2-hydroxyethyl)acrylamide; N-methyl-N-(2-hydroxypropyl)acrylamide; N-methyl-N-(2-hydroxyisopropyl)acrylamide; N-ethyl-N-(2-hydroxyethyl)acrylamide, 2-(N-methylprop-2-eneamido)acetic acid and α,β-unsaturated polyesterdiol produced by polycondensation of maleic anhydride, 1,3-propanediol and diethylene glycol in a molar ratio of 1:1:1.
It is very particularly preferable when in i)
the radical R4 represents —(C1-C12-alkyl)-X, where X=an NCO-reactive group, preferably an OH group,
the radical R8 represents —(C1-C12-alkyl)-X, where X=an NCO-reactive group, preferably an OH group, and
the radicals R18 and/or R19 represent —(C1-C12-alkyl)-X, where X=an NCO-reactive group, preferably an OH group.
Most preferred are hydroxyethyl acrylate (HEA), hydroxypropyl acrylate (HPA), 3-(acryloyloxy)-2-hydroxypropyl acrylate, 1,4-butanediylbis[oxy(2-hydroxy-3,1-propanediyl)] 2-propanoate, hydroxyethylacrylamide; N-methyl-N-(1,3-dihydroxypropyl)acrylamide; N-methyl-N-(2-hydroxyethyl)acrylamide; N-methyl-N-(2-hydroxypropyl)acrylamide; N-methyl-N-(2-hydroxyisopropyl)acrylamide; N-ethyl-N-(2-hydroxyethyl)acrylamide, 2-(N-methylprop-2-eneamido)acetic acid and α,β-unsaturated polyesterdiol produced by polycondensation of maleic anhydride, 1,3-propanediol and diethylene glycol in a molar ratio of 1:1:1 preferably having an OH number of 336 mg KOH/g, an acid number of 0.7 and a molecular weight factor per double bond of 262.
Employed as component C are aliphatic, cycloaliphatic, araliphatic, aromatic and heterocyclic polyisocyanates, such as are described for example by W. Siefken in Justus Liebigs Annalen der Chemie, 562, pages 75 to 136, for example those of formula (V)
Q(NCO)n (V)
in which
n=2-4, preferably 2-3,
and
Concerned here are, for example, polyisocyanates as described in EP-A 0 007 502, pages 7-8. Particular preference is generally given to the readily industrially obtainable polyisocyanates, for example 2,4- and 2,6-tolylene diisocyanate and any desired mixtures of these isomers (“TDI”); polyphenylpolymethylene polyisocyanates as prepared by aniline-formaldehyde condensation and subsequent phosgenation (“crude MDI”), and polyisocyanates containing carbodiimide groups, urethane groups, allophanate groups, isocyanurate groups, uretdione groups, uretdionimine groups, urea groups or biuret groups (“modified polyisocyanates”), especially those modified polyisocyanates which derive from 2,4- and/or 2,6-tolylene diisocyanate or from 4,4′- and/or 2,4′-diphenylmethane diisocyanate. Preferably employed as component B is at least one compound selected from the group consisting of 2,4- and 2,6-tolylene diisocyanate, 4,4′- and 2,4′- and 2,2′-diphenylmethane diisocyanate and polyphenyl polymethylene polyisocyanate (“polycyclic MDI”).
Very particularly preferably employed as component C is a diphenylmethane diisocyanate mixture consisting of
Employed as component C in an alternative very particularly preferred embodiment is a diphenylmethane diisocyanate mixture consisting of
The reaction components are reacted by the one-step process known per se, the prepolymer process or the semiprepolymer process often using mechanical means, for example those described in EP-A 355 000. Details of processing apparatuses which are also suitable in accordance with the invention are described in Kunststoff-Handbuch, volume VII, edited by Vieweg and Höchtlen, Carl-Hanser-Verlag, Munich 1993, for example on pages 139 to 265.
The isocyanate-reactive component B may for example initially be reacted with the isocyanate component C to afford a prepolymer and subsequently foamed with the polyol formulation A. A further option is that of initially mixing the isocyanate-reactive component B with the polyol formulation A and subsequently foaming with the isocyanate component C.
Preference is given to initially reacting the isocyanate-reactive component B with the isocyanate component C to afford a prepolymer and subsequently foaming the prepolymer with the polyol formulation A.
The PUR foams may be produced as molded foams or else as slabstock foams.
The molded foams may be produced by hot curing or else cold curing.
The invention therefore provides a process for producing the polyurethane foams, provides the polyurethane foams produced by this process, provides for the use of said foams for producing moldings or slabstocks and provides the moldings/the slabstocks themselves.
The polyurethane foams obtainable according to the invention find use for example in: furniture cushioning, textile inserts, mattresses, automotive seats, headrests, armrests, sponges and constructional elements and also seat and instrument panel trims, and have indices of 70 to 130, preferably 80 to 120, and densities of 4 to 600 kg/m3, preferably 60 to 120 kg/m3 (flexible foam) or 15 to 55 (semi-rigid foam).
The index (isocyanate index) indicates the percentage ratio of the actually employed isocyanate amount to the stoichiometric, i.e. calculated, isocyanate groups (NCO) amount:
Index=[(employed isocyanate amount):(calculated isocyanate amount)]·100 (VI)
The ratio of isocyanate groups to isocyanate-reactive groups multiplied by 100 is described as the index. The following tests always compare foams produced using the same index. In two test series an index below 100 (excess of isocyanate-reactive groups) and an index above 100 were established.
To produce the foams the required amount of polyol is initially charged into a cardboard beaker having a sheet metal bottom (volume: about 850 ml) and loaded with air using a stirring means (Pendraulik) fitted with a standard stirring disk (d=64 mm) at 4200 rpm for 45 seconds. Homogenization is carried out using a Pendraulik standard stirring disk (diameter 64 mm). The isocyanate/isocyanate mixture/prepolymer is weighed into a suitable beaker and emptied again (efflux time: 3 s). This beaker still having wet internal walls is tared and refilled with the reported isocyanate quantity. The isocyanate is added to the polyol formulation (efflux time: 3 s). The mixture is subjected to intensive mixing for 5 seconds using a stirring means (Pendraulik). A stopwatch is started at commencement of the mixing and the characteristic reaction times are read-off therefrom. About 93 g of the reaction mixture are poured into a teflon film-lined aluminum box mold having a volume of 1.6 dm3 and a temperature of 23° C. The mold is closed and locked. After six minutes the mold is unlocked, decompressed and the mold pressure is qualitatively assessed via the height by which the mold lid has been raised by the molding [mm]. The demolded foam cushion is qualitatively assessed for reaction completeness and for skin and pore structure. The reaction kinetics are determined using the residual reaction mixture in the beaker.
After production all foams were stored in a fume cupboard at 20-23° C. for 7 days.
Some of the foams were packaged in aluminum foil and stored in a circulating air drying cabinet at 90° C. before measurement of the aldehyde emissions. These foams are described as “aged”.
Compressive strength and damping were measured on test specimens having dimensions of 5*5*5 cm3 parallel to the foaming direction at 40% compression. A pre-loading of 2 kPa was established.
The advancing rate was 50 mm/min.
Hydroxyl number was determined to DIN 53240.
a) Measurement Method 1 (Bottle Method According to VDA 275):
b) Measurement Method 2 (Modified Bottle Method):
For illustration of the methods the emissions for the combination of the standard polyol formulation with isocyanate B1 are shown below:
The polyol component employed was a polyether mixture of a glycerol-started polyalkylene oxide having a molar weight of 4.8 kg/mol and a propylene glycol-started polyalkylene oxide having a molar weight of 4 kg/mol. The weight ratio of the two polyethers was 55:45.
The polyol component further contains various additive substances.
Isocyanates:
In contrast to isocyanates B3 and B4 no activity of the isocyanate B2 on acetaldehyde emissions is detectable.
At higher indices the differences are less marked yet still apparent. In contrast to isocyanates B3 and B4, no activity of the isocyanate B2 on acetaldehyde emissions is detectable even at elevated indices.
| Number | Date | Country | Kind |
|---|---|---|---|
| 16202104.2 | Dec 2016 | EP | regional |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 16466380 | Jun 2019 | US |
| Child | 17152853 | US |
