Patent Application
20190359761
It is known from the prior art about 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, 3 h 60° C.) or else according to VDA 276 (emissions chamber test, 65° C.).
Both EP2138520 and WO2015082316 describe 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.
Hydrazides such as acethydrazide have likewise been described as suitable additives for reducing formaldehydes (EP 1674515). Polyhydrazodicarbonamides, obtainable from the reaction of hydrazine with isocyanates, are also suitable for this purpose. However, these have the disadvantage that they are in the form of particles and rigidify foams. This is not desired for flexible foams. The same problem appears when using polyurea dispersions which are likewise suitable for reducing the formaldehyde emissions from foams.
The present invention has for its object to provide polyurethanes, preferably polyurethane foams, exhibiting even lower formaldehyde emission than polyurethanes/polyurethane foams of the prior art. This object was achieved with the following process:
The present invention 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 one or more compounds selected from the group consisting of:
NC—CHR1—CONR12—X (I),
NC—CHR2—CONR3-aryl (II),
NC—CHR4—CO2H (III),
[NC—CHR5—CO2]mYm+ (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 polyurethanes, preferably polyurethane foams, which comprises reacting with one another
NC—CHR1—CONR12—X (I),
NC—CHR2—CONR3-aryl (II),
NC—CHR4—CO2H (III),
[NC—CHR5—CO2]mYm+ (IV),
The usage amount of the inventive component A5 based on 1 kg of the components A1 and B is 1 to 100 g, preferably 5 to 50 g (the value of 1 kg relates to the sum of A1 and B).
Very particular preference (alternative I) is given to a process for producing polyurethanes, preferably polyurethane foams, which comprises reacting with one another
NC—CHR1—CONR12—X (I),
NC—CHR2—CONR3-aryl (II),
NC—CHR4—CO2H (III),
[NC—CHR5—CO2]mYm+ (IV),
Likewise very particularly preferred (alternative II) is a process for producing polyurethanes, preferably polyurethane foams, which comprises reacting with one another
NC—CHR1—CONR12—X (I),
NC—CHR2—CONR3-aryl (II),
NC—CHR4—CO2H (III),
[NC—CHR5—CO2]mYm+ (IV),
It has been found that compounds of formulae (I) to (IV) (component A5) are surprisingly more effective as aldehyde scavengers than the hitherto known compounds. The invention therefore further provides for the use of one or more compounds of formulae (I) bis (IV) in polyurethane compositions or in processes for producing polyurethanes, preferably polyurethane foams, for reducing the formaldehyde emission of the polyurethanes/polyurethane foams resulting therefrom.
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, Polyurethanes, 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 of the 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, preferably ≥20 to ≤150 mg KOH/g, particularly preferably ≥20 to ≤50 mg KOH/g, very particularly preferably ≥25 to ≤40 mg KOH/g. These include 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 such 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 and particularly preferably 6-10% by weight based on the total weight of all polyoxyalkylene polymers.
In addition to the 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 (polyureadispersion) 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 producing 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 2.5 to 4 and a hydroxyl number of ≥3 mg KOH/g to ≤112 mg KOH/g (number-average molecular weight 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 A1.
Further examples of compounds of component A2 are described in EP-A 0 007 502, pages 16-17.
Employed as component A3 are water and/or physical blowing agents. Employed as physical blowing agents are, for example, carbon dioxide and/or volatile organic substances as blowing agents.
Employed as component A4 are auxiliary and additive substances such as
These auxiliary and additive substances for optional co-use are described for example in EP-A 0 000 389, pages 18-21. Further examples of auxiliary and additive substances for optional co-use according to the invention and also details concerning ways these auxiliary and additive substances are used and function are described in Kunststoff-Handbuch, 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. The functional group is preferably a hydroxyl group or a primary or secondary amino group. These particularly preferred catalysts have the advantage that they exhibit strongly 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.
Component A5 comprises compounds selected from the group consisting of:
NC—CHR1—CONR12—X (I),
NC—CHR2—CONR3-aryl (II),
NC—CHR4—CO2H (III),
[NC—CHR5—CO2]mYm+ (IV),
In a preferred variant the radicals R1 to R12 each independently of one another represent H or a C1-C6 alkyl group. In a particularly preferred variant the radicals R1, R2, R4 and R5 independently of one another represent H and the radicals R3 and R6 to R12 independently of one another represent H or a C1-C6 alkyl group.
Of the compounds (I) bis (IV), the compounds (I) and (II) are preferred for use in the process according to the invention.
Employed as component B 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
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, 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 B is a diphenylmethane diisocyanate mixture consisting of
Employed as component B 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 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 preferably 15 bis 55 kg/m3 (semi-flexible 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)
In a first embodiment the invention relates to a process for producing polyurethanes by reaction of compounds containing isocyanate-reactive hydrogen atoms with di- and/or polyisocyanates in the presence of one or more compounds selected from the group consisting of:
NC—CHR1—CONR12—X (I),
NC—CHR2—CONR3-aryl (II),
NC—CHR4—CO2H (III),
[NC—CHR5—CO2]mYm+ (IV),
In a second embodiment the invention relates to a process for producing polyurethanes, preferably polyurethane foams, which comprises reacting with one another
NC—CHR1—CONR12—X (I),
NC—CHR2—CONR3-aryl (II),
NC—CHR4—CO2H (III),
[NC—CHR5—CO2]mYm+ (IV),
In a third embodiment of the invention the invention relates to a process according to embodiment 1 or 2, wherein
the usage amount of the compounds (I) to (IV) based on 1 kg of the compounds containing isocyanate-reactive hydrogen atoms and the di- and/or polyisocyanates is 1 to 100 g, preferably 5 to 50 g (claim 1), and the usage amount of the component A5 based on 1 kg of the components A1 and B is 1 to 100 g, preferably 5 to 50 g (claim 2).
In a fourth embodiment of the invention the invention relates to a process for producing polyurethanes, preferably polyurethane foams, according to embodiment 2 or 3 which comprises reacting with one another
NC—CHR1—CONR12—X (I),
NC—CHR2—CONR3-aryl (II),
NC—CHR4—CO2H (III),
[NC—CHR5—CO2]mYm+ (IV),
In a fifth embodiment of the invention the invention relates to a process for producing polyurethanes, preferably polyurethane foams, according to embodiment 2 or 3 which comprises reacting with one another
NC—CHR1—CONR12—X (I),
NC—CHR2—CONR3-aryl (II),
NC—CHR4—CO2H (III),
[NC—CHR5—CO2]mYm+ (IV),
In a sixth embodiment of the invention the invention relates to the use of one or more compounds selected from the group consisting of:
NC—CHR1—CONR12—X (I),
NC—CHR2—CONR3-aryl (II),
NC—CHR4—CO2H (III),
[NC—CHR5—CO2]mYm+ (IV),
In a seventh embodiment of the invention the invention relates to a process or a use according to any of embodiments 1 to 6, wherein in the compounds (I) to (IV) R1 to R12 each independently of one another represent H or a C1-C6 alkyl group.
In an eighth embodiment of the invention the invention relates to a process or a use according to claim 7, wherein R1, R2, R4 and R5 independently of one another represent H.
In a ninth embodiment of the invention the invention relates to a process according to any of embodiments 1 to 5, 7 or 8, wherein as the compounds containing isocyanate-reactive hydrogen atoms (component A1) at least two hydroxyl-containing polyethers, optionally in admixture with at least two hydroxyl-containing polyesters, are employed.
In a tenth embodiment of the invention the invention relates to a process according to any of embodiments 1 to 5, 7 to 9, wherein the component consisting of compounds containing isocyanate-reactive hydrogen atoms (component A1) contains at least 30% by weight of at least one polyoxyalkylene copolymer consisting of a starter, propylene oxide and ethylene oxide and an end block made of ethylene oxide, wherein the total weight of the end blocks made of EO 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 copolymers.
In an eleventh embodiment of the invention the invention relates to a process according to any of embodiments 1 to 5 or 7 to 10, wherein as the di- and/or polyisocyanate component (component B) a diphenylmethane diisocyanate mixture consisting of
In a twelfth embodiment of the invention the invention relates to a process according to any of embodiments 1 to 5 or 7 to 10, wherein as the di- and/or polyisocyanate component (component B) a diphenylmethane diisocyanate mixture consisting of
In a thirteenth embodiment of the invention the invention relates to a process for producing polyurethanes, preferably polyurethane foams, according to embodiment 4, 9 or 10 which comprises reacting with one another
NC—CHR1—CONR12—X (I),
NC—CHR2—CONR3-aryl (II),
NC—CHR4—CO2H (III),
[NC—CHR5—CO2]mYm+ (IV),
In a fourteenth embodiment of the invention the invention relates to a process for producing polyurethanes, preferably polyurethane foams, according to embodiment 4, 9 or 10 which comprises reacting with one another
NC—CHR1—CONR12—X (I),
NC—CHR2—CONR3-aryl (II),
NC—CHR4—CO2H (III),
[NC—CHR5—CO2]mYm+ (IV),
In a fifteenth embodiment of the invention the invention relates to a process for producing polyurethanes, preferably polyurethane foams, according to embodiment 4, 9 or 10 which comprises reacting with one another
NC—CHR1—CONR12—X (I),
NC—CHR2—CONR3-aryl (II),
NC—CHR4—CO2H (III),
[NC—CHR5—CO2]mYm+ (IV),
In a sixteenth embodiment of the invention the invention relates to a process for producing polyurethanes, preferably polyurethane foams, according to embodiment 4, 9 or 10 which comprises reacting with one another
NC—CHR1—CONR12—X (I),
NC—CHR2—CONR3-aryl (II),
NC—CHR4—CO2H (III),
[NC—CHR5—CO2]mYm+ (IV),
In a seventeenth embodiment of the invention the invention relates to a process for producing polyurethanes, preferably polyurethane foams, according to embodiment 4, 9 or 10 which comprises reacting with one another
NC—CHR1—CONR12—X (I),
NC—CHR2—CONR3-aryl (II),
NC—CHR4—CO2H (III),
[NC—CHR5—CO2]mYm+ (IV),
In an eighteenth embodiment of the invention the invention relates to a process for producing polyurethanes, preferably polyurethane foams, according to embodiment 4, 9 or 10 which comprises reacting with one another
NC—CHR1—CONR12—X (I),
NC—CHR2—CONR3-aryl (II),
NC—CHR4—CO2H (III),
[NC—CHR5—CO2]mYm+ (IV),
In a nineteenth embodiment of the invention the invention relates to a process for producing polyurethanes, preferably polyurethane foams, according to embodiment 4, 9 or 10 which comprises reacting with one another
NC—CHR1—CONR12—X (I),
NC—CHR2—CONR3-aryl (II),
NC—CHR4—CO2H (III),
[NC—CHR5—CO2]mYm+ (IV),
In a twentieth embodiment of the invention the invention relates to a process for producing polyurethanes, preferably polyurethane foams, according to embodiment 5, 9 or 10 which comprises reacting with one another
NC—CHR1—CONR12—X (I),
NC—CHR2—CONR3-aryl (II),
NC—CHR4—CO2H (III),
[NC—CHR5—CO2]mYm+ (IV),
In a twenty-first embodiment of the invention the invention relates to a process for producing polyurethanes, preferably polyurethane foams, according to embodiment 5, 9 or 10 which comprises reacting with one another
NC—CHR1—CONR12—X (I),
NC—CHR2—CONR3-aryl (II),
NC—CHR4—CO2H (III),
[NC—CHR5—CO2]mYm+ (IV),
In a twenty-second embodiment of the invention the invention relates to a process for producing polyurethanes, preferably polyurethane foams, according to embodiment 5, 9 or 10 which comprises reacting with one another
NC—CHR1—CONR12—X (I),
NC—CHR2—CONR3-aryl (II),
NC—CHR4—CO2H (III),
[NC—CHR5—CO2]mYm+ (IV),
In a twenty-third embodiment of the invention the invention relates to a process for producing polyurethanes, preferably polyurethane foams, according to embodiment 5, 9 or 10 which comprises reacting with one another
NC—CHR1—CONR12—X (I),
NC—CHR2—CONR3-aryl (II),
NC—CHR4—CO2H (III),
[NC—CHR5—CO2]mYm+ (IV),
In a twenty-fourth embodiment of the invention the invention relates to a process for producing polyurethanes, preferably polyurethane foams, according to embodiment 5, 9 or 10 which comprises reacting with one another
NC—CHR1—CONR12—X (I),
NC—CHR2—CONR3-aryl (II),
NC—CHR4—CO2H (III),
[NC—CHR5—CO2]mYm+ (IV),
In a twenty-fifth embodiment of the invention the invention relates to a process for producing polyurethanes, preferably polyurethane foams, according to embodiment 5, 9 or 10 which comprises reacting with one another
NC—CHR1—CONR12—X (I),
NC—CHR2—CONR3-aryl (II),
NC—CHR4—CO2H (III),
[NC—CHR5—CO2]mYm+ (IV),
In a twenty-sixth embodiment of the invention the invention relates to a process for producing polyurethanes, preferably polyurethane foams, according to embodiment 5, 9 or 10 which comprises reacting with one another
NC—CHR1—CONR12—X (I),
NC—CHR2—CONR3-aryl (II),
NC—CHR4—CO2H (III),
[NC—CHR5—CO2]mYm+ (IV),
In a twenty-seventh embodiment of the invention the invention relates to polyurethanes/polyurethane foams obtainable by a process according to any of the embodiments 1 to 5 or 7 to 26.
In a twenty-eighth embodiment of the invention the invention relates to polyurethanes/polyurethane foams according to embodiment 27 having a density of 4 to 600 kg/m3 (flexible/semi-flexible polyurethane from), preferably 60 to 120 kg/m3 (flexible polyurethane foam) and preferably 15 to 55 kg/m3 (semi-flexible foam)
In a twenty-ninth embodiment of the invention the invention relates to polyurethanes/polyurethane foams according to embodiment 27 or 28 for producing furniture cushioning, textile inlays, mattresses, automotive seats, headrests, armrests, sponges, headlinings, door trims, seat covers or constructional elements.
Compressive strength, damping and apparent density of the foams were determined in the foam expansion direction according to DIN EN ISO 3386-1. The test specimens had a volume of 5*5*5 cm3. A pre-loading of 2 kPa was established. The advancing rate was 50 mm/min.
The hydroxyl number was determined according to DIN 53240.
The open-cell content was measured with an AccuPyc 1330 gas displacement pycnometer.
The glass transition reported is the maximum of tan 6 according to DIN EN ISO 6721-2 B (torsion pendulum method).
VDA 275 is a standardized test method of the organization Verband der Automobilindustrie (VDA). The version current at the date of filing is employed here.
The production of the polyurethane foams is carried out by mixing a polyol formulation A and an isocyanate component B.
The reported OH numbers are obtained according to DIN 53240 in the version current at the date of filing.
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.
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.
The cream time has been attained when an expanding of the mixture is observable.
The fiber time has been attained when strings can be pulled from the surface of the rising foam by dabbing with a wooden spatula. Alternatively, lumps form on the spatula.
The rise time has been attained when the foam finally ceases to expand. It should be noted here that some systems have a propensity to undergo some sagging before rising again.
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”.
The compressive strength was measured at 40% compression parallel to the foaming direction. A pre-loading of 2 kPa was established. The advancing rate was 50 mm/min.
The familiar effect that increasing the index reduces aldehyde emissions is observed. At an identical index the foams according to the invention show moderately to markedly reduced aldehyde emissions.
The modified method increases the visibility of formaldehyde. Surprisingly, the ageing results in a reversing of the initially positive effect of a higher index.
Before and after aging the addition of cyanoacetic acid has a positive effect on formaldehyde emissions.
(Delimitation from EP 1674515)
The content is reported in % by weight. DHBH is the reaction product of hydrazine hydrate and cyclic propylene carbonate (1:2 molar), KCA is potassium cyanoacetate K+[NC—CH2—CO2]−. CMPA is 2-cyano-N-methyl-N-phenylacetamide NC—CH2—CO—N(CH3)(C6H5)
All foams are produced with an index of 90.
The compressive strength was measured at 10% compression parallel to the foaming direction.
The inventive examples show a somewhat higher hardness at slightly better elasticity compared to use of acethydrazide. This is advantageous in use as a core ply in sandwich components such as automotive headlinings.
The open-cell content was measured with an AccuPyc 1330 gas displacement pycnometer.
The inventive examples show somewhat higher open-cell content compared to use of acethydrazide. This is advantageous for use in sound-absorbing applications.
The results confirm the literature: Acethydrazide is in principle suitable for reducing the formaldehyde emissions from foams. However, cyanoacetylurea and other derivatives of cyanoacetic acid are significantly more effective.
In the experiments 90 D and 90 E the acetaldehyde emissions were reduced from 0.6 mg/kg (comparative 90V5) to 0.5 and 0.3 mg/kg respectively.
(Delimitation from EP2138520)
Cyanoacetamide is known as a cell opener. It is accordingly not surprising that foams that contained cyanoacetamide were unstable and in one case collapsed. In the case of the foams 80 V2, 90 V6 and 100 V2 the blowing agent content was increased by 0.5 parts by weight and 1.5 parts by weight of Jeffcat DPA were added to obtain an approximately comparable apparent density.
The test comprising employing cyanoacethydrazide as an additive results in foam collapse at an index of 100. The test with an index of 110 was not performed.
The results confirm the literature: Cyanoacetamide is suitable for reducing formaldehyde emissions.
It is apparent that cyanoacethydrazide is not only likewise well suited for reducing the formaldehyde emissions. This applies in particular after aging.
The use of cyanoacethydrazide also makes it possible to produce foams over a wider index range.
This is of great advantage for industrial use since foams are easier to adapt to customer requirements.
(Delimitation from EP2138520).
The two components A and B were brought to reaction with an index of 100.
The usage amounts of cyanoacetamide A5-7 and cyanoacethydrazide A5-3 are 7.1 and 6.0 mmol/kg of foam respectively.
The input materials recited in the examples are reacted with one another in the one-stage process in the manner of processing customary for the production of flexible moulded polyurethane foams in the cold-cure process. The reaction mixture at a temperature of 24° C. is introduced into a metal mold (volume 9.7 dm3) that has been heated to 60° C. and previously coated with a release agent (PURA E1429H NV (Chem-Trend)). The usage amount is employed according to the desired apparent density and mold volume. The moldings were demolded and wrung-out after 4 minutes. After 4 hours the moldings were sealed in aluminum composite film.
The formaldehyde emissions were determined according to method 2.
The acetaldehyde emissions are 0.6 mg/kg without an additive. Both additives reduce the acetaldehyde emissions to below the limit of detection of 0.3 mg/kg.
It is apparent here too that cyanoacetamide is suitable for reducing emissions of formaldehyde.
Here too, cyanacethydrazide is even more effective.
| Number | Date | Country | Kind |
|---|---|---|---|
| 16204942.3 | Dec 2016 | EP | regional |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2017/083346 | 12/18/2017 | WO | 00 |
