CA2189891A1 - Flexible polyurethane slab stock foam having superior feel, comfort and wear characteristics - Google Patents
Flexible polyurethane slab stock foam having superior feel, comfort and wear characteristicsInfo
- Publication number
- CA2189891A1 CA2189891A1 CA 2189891 CA2189891A CA2189891A1 CA 2189891 A1 CA2189891 A1 CA 2189891A1 CA 2189891 CA2189891 CA 2189891 CA 2189891 A CA2189891 A CA 2189891A CA 2189891 A1 CA2189891 A1 CA 2189891A1
- Authority
- CA
- Canada
- Prior art keywords
- foam
- percent
- flexible polyurethane
- isocyanate
- stream
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Landscapes
- Polyurethanes Or Polyureas (AREA)
- Manufacture Of Porous Articles, And Recovery And Treatment Of Waste Products (AREA)
Abstract
More particularly, the invention relates to a polyurethane slab stock foam characterized by (a.) a cell size distribution wherein at least 20 percent of the cells visible in a cross-section of the foam have a diameter of at least 0.1mm, (b.) a catastrophic fatigue value characterized by (1.) a percent loss in height of no more than 10% and (2.) a percent hardness retained (65 percent IFD deflection) of no less than 50%, and (c.) a substantial absence of cells having a diameter of at least 1mm. The invention further provides a process of making said foam as well as a method of reducing the number of defects in polyurethane foam wherein such defects have an average diameter of at least 1mm.
Description
2 1 8989 ~
E',r.~8rTRT,I;~ pr~T.~!l~l~t;rR ,qT.l~R 5Tt-rT~ Fl'~AM ~TAV,TNa S~pT'T~T-~ FTIT~T., CQ~5FORT, ~ W~AT~ r~T~T ~rTRTlTCTIrC
PiPl-l of ~hP InvPntinn The present invention provides a flexible polyurethane slab stock foam having superior feel, comfort, and wear characteristics, a process for making the same, and a method of reducing the number of defects in a polyurethane foam, wherein the defects have a diameter which is at least four times greater than the common cell 20 size.
More r~rti c ~ rly, the invention relate8 to a polyurethane slab stock foam characteri2ed by (a. ) a cell size distribution wherein at lea8t 20 percent of the cells visible in a cross-section of the foam have a diameter of at least 0.1 mm, and (b.) a 25 substantial absence of cells having a diameter which is at least four time8 greater than the common cell si2e diameter. The foams of the invention are further definaole as having a catastrophic fatigue value rh~r~n~,orized by (1) a percent 1088 in height of no more than 10 percent, and (2) a percent hardness retained (65 30 percent IED) of no less than 50 percent.
' ~ 2189891 Backgrrl~n~ of th~ TnV~nt;nn The production of high quality flexible polyurethane slab stock foam has long been a goal of the polyurethane foam industry.
Slab stock foam physical ;Ittr;h~c~c are defined under ASTM D3574 and D3770 6tandard specifications for Flexible Cellular ~-tPr;;~lc ;nrl.-~;n~ but not limited to conventional, high resilience, and combustion modified high rpc;l;onrf~ polyurethane foam. Carpet cu6hion foam standards are spPr;f;f~rl in but are not limited to E~UD
UM72a. Foams having optimum levels of feel, comfort and wear 15 characteristics as well as a desirable visual d~ L~ e:, have been particularly difficult to achieve.
The performance re~uirements of some end uae Prpl;rAt;nnc have been ~r~r;~11y challenging. For example, carpet cushion has particularly rigorous performance rer~uirements which have been 20 difficult to achieve while ~-;n~;n;n~ a balance of the other desirable properties.
High r~uality carpet cushion should have a plush or pleasantly soft feel to the touch. Optimally, those skilled in the art would like a user of the carpet cushion to experience a sinking or 25 floating feeling when walking or r~sting upon the cush~on.
In addition, high quality polyurethane foam carpet cushion must simultaneously eYhibit both short term and long term resistance to compression and the results of repeated use. The foam muat not "bottom out" or give way under successive every day use .
Also, the carpet cushion must eYhibit improved wear characteristics with respect to both itself and the wear of any carpet used thereon. That is, the cushion must serve to improve the long term performance of the carpet and thus must not hasten carpet degradation with undesirable wear of the carpet cushion 15 itself.
~ inally, the carpet cushion must be visually ~E~PP~l ;n~ to both wholesale and retail l_:U112~ . In particular, high quality slab stock polyurethane foama intended for use as carpet cushion must be substantially free from visible defects. ~Y---;n~t;nn of a cross-20 section of traditional slab stock foam will generally reveal thepresence of voids which can be defined in terms of their diameter.
The perception of what constitutes a void is to some eYtent ~p~n~Pn~ upon the gize of the cells which prf~ n~ in the foam, i.e. common cell size diameter. Common cell size diameter may be 25 defined as the average diameter of the most prevalent cells which , have a diameter which i5 within + or - 10096 of each other.
Preferably, the common cell size diameter will be the average diameter of those cells which have a diameter which i8 within + or - 5096 of each other. Most preferably, the common cell size diameter will be the average diameter of the most prevalent cell6 having a diameter which i8 within + or - 309~ of each other.
For example, in foams having a common cell size of 0.5 mm, cells having a diameter of from 1 mm to 3 mm would generally be viewed as a defect called buckshot, while cells having an average diameter of 3 mm to 6 mm would generally be defined as a peahole defect. In general, a defect may be defined as a void apparent in a cross section of a foam which has a diameter which is at least four times greater than the common cell size diarneter. Preferably, t~le foams of the invention will have a substantial absence of voids having a diameter which is at least three time greater than the common cell size diameter. Most preferably, the foams of the invention will have a substantial absence of voids having a diameter which is twice that of the common cell size diameter.
Defects generally arise as a result of the entrapment of air and high viscosity ~ during the formation of the foam~
25 Alr entra1 sd in th~ ~reth~e ~ = dur1n~ tr~na~r to u~d ' ~ 2~89~91 5 from storage vessels and metering ~ ;rmPnt, plus inconsistent processing habits are believed to be possible causes of foam def ects .
Thus, it is an object of the instant invention to provide a flexible polyurethane slab stock foam which has superior feel, 10 comfort and wear characteristics and which has a substantial absence of cells having a diameter which is at least four times greater than the common cell size diameter.
It is another object of the invention to provide such foams which also exhibit fatigue values characterized by ~1) a percent 15 loss in height of no more than 10 percent and (2) a percent retained (65 percent IFD) of no less than 50 percent.
Finally, it is an object of the invention to provide a process of making such foam as well as a method of reducing the number of defects in polyurethane foam wherein such defects have a diameter ~0 which is a least four times greater than the common cell size.
S11mm~rv of the Inv~ntion The foregoing ob~ect and more are achieved with the flexible polyurethane slabstock foam of the invention. Such foam results from a process of making wherein a stream of an isocyanate ~ nt~;n;n~ llt is provided along with a stream of a polyol 2 i7 89~9. 1 , 5 L , ' having a blowing agent which is r~7r~7n~7;hle for at least 95 percent and preferably, 100 percent, of the l~r;7n~7;~n of the foam. An amount of an inert gas is injected into one or more of the isocyanate or polyol ~ ~ streams, the amount of injected gas being capa~le of producing only negligible P~r 7nq; ~m of the 10 foam. The isocyanate and polyol ~ _ streams are reacted together for a time 8ufficient to produce a polyurethane foam. The resultant polyurethane slab stock foam is ~ h;7r;7rt~ri 70~7. by (a. ) a cell size distr;h77t;~7n where at least 20 percent of the cells vi8ible in a cross sectio7~ of the foam have a diameter of at least 15 0 .1 m!n, and (b. ) a substantial absence of cell8 having a diameter which is at least four times greater than the common cell size diameter. me resulting foam is further ;r7.ont;7~ 7. by a catastrophic fatigue value r h~7r~7~ t~r7 7~7 by (1) a percent 1088 in height of no more than 10 percent and (2) a percent retained (65 20 percent IPD) of no less than 50 percent.
me invention also provides a method of reducing the nun7ber of defects in polyurethane foam wherein the defects have a diameter which is at least four times greater than the common cell size diameter. The method involves the provision of a stream of an 1rocyrpate r~nt/ll~;n~ r, rP the provi~li~ Or a rtrer Or 1-" ~ 2189891 5 polyol component having a blowing agent which is r~rnn~ihl e for at least 95 percent of the ~ n~; nn of the foam. An amount of inert gaa ia inj ected into one or more of the iaocyanate or polyol nn~nt gtreams, the amount inj ected being capable of producing only negligible expan6ion of the foam. The streams are reacted ~0 together for a time sufficient to produce a polyurethane foam.
Descr;~tion of the Draw;n,r~:
Figure 1 is a cross sectional photographic view of a prior art foam having a defect therein.
Figure 2 is a cross sectional photographic view o~ a foam of 15 the invention having 6ubatantially no defects.
Figure 3 ia a cross ~l~rt;nn~l photographic view of a second foam of the invention having substantially no defects.
De~ orl Deacr; ~tion of the Invention The flexible polyurethane slab stock foam of the invention 20 exhibits superior feel, comfort and wear characteriatics. It iB
obtained from a particular procesa of making which requires the inj ection of an amount of inert gas into one or more isocyanate or polyol CU...,~ steams. The amount of inert gas injected is capable of producing only norjl; g; hl e, if any, ~n~; nn of the 25 foam .
2 1 8989 ~
The stream of an isocyanate cnn~;n;n~ U~ lt will generally be comprised of one or more organic isocyanates. Organic polyisocyanates suitable for use in the instant invention ~:ULL~#~Vlld to the formula R' (NCO) z wherein R' is a polyvalent organic radical which is either aliphatic, arylalkyl, alkylaryl, aromatic or mixtures thereof and z i5 an integer which ~uLLc:#~ulld8 to the valence of R' and is at lea8t 2.
Representative of the types of organic polyisocyanates ntP~r~rli~ herein include, for example, 1,2-diisocyanatoethane, 1, 3-diisocyAn~tnrror~AnP, 1, 2-diisocyanatopropane, l, 4-diisocyanatobutane, 1,5-diisocyanatopentane, 1,6-dissocyanatohexane, bis (3-isocyanatopropyl) ether, bis (3-isocyanatopropyl) sulfide, 1, 7-dii80cyanatoheptane, 1, 5-diisocyanato-2,2-dimethylpentane, 1,6-diisocyanate-3-methu~yl~ a~ld, 1,8-diisocyanatoctane, 1,5-diisocyanato-2,2,4-trimethylpentane, l,9-diisocy~n~r-- , l,10-diisocyanatopropyl ether o~ 1,4-butylene glycol, l,ll-diisocy~n~tmlntlPr:~np, 1,12-diisocy~n~tr~nflPr;~nf" bis(isocyanatohexyl)sulfide, ,4-diisocyanatobenze, 1,3-diisocyanato-o-xylene, 1,3-diisocyanato-p-xylene, 1,3-diisocyanato-m-xylene, 2,4-diisocyanto-1-chlorobenzene, 2s 2,4-diiaocy~nato 1 nitro b~n~ene, 2,5 dli~o y~n:to-l-nlLLu~ e~
21898ql S m-phenylene diisocyanate, 2,4-toluene diiEocyanate, 2,6-toluene diisocyanate, mixtures of 2,4- and 2,6-toluene diisocyanate, 1,6-hexamethylene diisocyanate, 1, 4-tetramethylene diisocyanate, 1, 4-cyr1~hPlr~nP diisocyanate,hexahydrotoluene diisocyanate, 1,5-naphthalene diisocyanate, 1-methoxy-2,4-phenylene diisocyanate, lO 4,4'-cyclohexane diisocyanate, hexahydrotoluene diisocyanater l,S-n;~rh~h~lPnP diisocyanate, 1-methoxy-2,4-phenylene diisocyanate, 2,4'-4,4'-diphenylmethane diiEocyanate, 4,4'-biphenylene diisocyanate, 3,3'-dimethyl-4,4'-diphenylmethane diisocyanate; the triisocyanates such as 4,4' ,4"-triphenylmethane triisocyanate 15 polymethylene polyphenylene polyisocyanate and 2,4,6-toluene triisocyanate; and the tP~r~;Rrryanates such as 4,4'-dimethyl-2,2'-5, 5 ' -diphenylmethane tetraisocyanate.
The polyisocyanates are prepared by conventional methods known in the art such as the phoE~n~ n of the corresponding organic 20 amine or equivalent processes.
Included within the useable isocyanates are the modifications of the above isocyanates which contain r~rhr,tl1;m;rlP, Alloph~1n~te or isocyanurate structures. Uretr,n;m;nP-carbodimide derivatives of PRRPn~ l l y pure diphenylmethane diisocyanate can be made by well-25 known techniques, such as the conversion o~ a portion of the 21 89~9 1 , 5 isocyanate groups in diphenylmethane diisocyanate to a carbodiimideby using a phosphorus-rnnt~in;ng catalyst at elevated temperatures, and then allowing the r~rhn~9;;m;-1~ modified diphenylmethane diisocyanates to further react with unreacted isocyanates groups to form urPtnn;m;n~ modified MDI. The conversion from r~rhnr~;;m;rlo 10 modified MDI to uretonimine modified MOI does not typically go to completion, having a composition ~ nnt~;n;n~ small amounts of ~ rhn.l;;m;~,, groups. Typically from about 10 to 35 percent by weight of the ~I as converted to urPt~n;m;nP-~rhnrl; ;m;~P modified MDI species leaving from 65 to 90 percent of the MDI unreacted.
PrepolymerY and quasi-prepolymers may also be employed in the process of the subject invention. These prepolymers ~uasi-prepolymers are prepared by reacting an excess of organic polyisocyanate or mixtures thereof with a minor amount of an active hydrogen-~-nnt~;n;n~ compound as determined by the well-known 20 Zerewitinoff test as described by Kohler in Journal of the American Chemical Society, 49, 3181 (1927). The3e ~ ,,uulLds and their methods of preparation are well known in the art. The use of any one ~pecific active hydrogen compound is not critical hereto, rather any such compound can be employed herein. Generally, the 25 qua~i-prepolym~r~ have a ~ree l~oc ~at- content ~e erom 2~ per~ent , 5 to 40 perce~t by weight while prepolymers will have a free isocyanate content of from 2 to 15 percent by weight.
Especially useful due to their avA; l ~h; l; ~y and properties are toluene diisocyanate, 2,4'-diphenylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate, polymethylene polyphenylene lO polyisocyanate, modified isocyanates .as described above, and mixtures thereof.
However, it has been found that the preferred isocyanate f~nn~i~;n;n~ ~nmrnn~n~ will be comprised of mixtures of diphenylmethane diisocyanate (MDI) isQmer5,, 'lfi~-1 isocyanates 15 ~nnt~ln;n~ ure~nnP;m;n~ r;lrhQ-l;;m;~, allophanate and/or isocyanaurate structures, and toluene diisocyanate (TDI)~
A preferred MDI isomer is 4,4'-diphenylmethane diisocyanate.
Preferred modified isocyanates will generally have from 5 to 50%
carbodiimide, with 10 to 3096 being most preferred. While any 20 suitable TDI may be used, such as 2,4-TDI or 2,6-TDI, mixtures c~nn~;~;n;n~ from about 65 to 85 percent 2,4-TDI and the balance 2,6-TDI are preferred. A particularly preferred isocyanate rnnt~;n;n~
~ , -' will comprise from 20 to 95 weight percent 4,4-MDI
isomer, 1 to 60 weight percent ~ ~;fi~-7 isocyanate, and 1 to 60 25 weight per~ent TDI.
~ 218~91 The most preferred isocyanate ~~nnt~;n;n~ . ~n~ will comprise from 30 to 80 weight percent 4,4'-~I, 5 to 50 weight percent r 'ifi.~rl isocyanate, and 5 to 50 percent TDI.
The stream of polyol, ,lu~ llL may also be termed the resin side or isocyanate reactive ~nmrnn_n~ This ~ ~UIl~ will generally be comprised of a blend of a polyol, a urethane promoting catalyat, a blowing agent, and optionally, one or more additives selected from the group consisting of surfactants, chain extenders, flame ;nh;h;t-nrs~ An~;nY;~n~R~ and mixtures thereof.
Polyols may be defined as compounds having at least two isocyanate reactive llydlug~ ~IA which may be employed in the preparation of polyurethane foams and elastomers. They are often prepared by the catalytic cnnrl_nR~;nn of an alkylene oxide or mixture of alkylene oxides either simultaneously or g.~~ ~n~;~lly with an orga~ic compound having at least two active hydrogen atoms, such as evidenced by U.S. Pat. Nos. l,922,459; 3,190,927; and 3,346,557. Representative polyols include polyhydroxyl-cnn~A;n;n~~J
polyesters, polyoYyalkylene polyether polyols such as the aful~ ' ;nn_rl polyoxyalkylene polyether polyols, polyhydroxy-terminated polyurethane polymers, polyllydlu~Lyl-~~nn~A;n;n~;
pho~phora~ rr~~ lkylene oxi~e adi~ct~ of polyhydric . , .
218q8ql 5 polythioesters, polyacetals, aliphatic polyols and thiols, ammonia, and amines ~nr1~l~1;ng aromatic, aliphatic, and heterocyclic amines, as well as mixtures thereof. Alkylene oxide adducts of ~ ~JUII~
which contain two or more different groups within the above-defined classes may also be used, for example, amino alcohols which contain lD an amino groups and a hydroxyl group. Also, alkylene oxide adducts of compounds which contain one SH group and one OH group as well as those which contain an amino groups and an SH group may be used.
Generally, the number average l e~ r weight of the polyols will vary from greater than 400 to 10, 000, and preferably from 2500 to 7, 000 .
Any suitable hydroxy-~Prm;n~tod polyester may be used such as are prepared, for example, from polycarboxylic acids and polyhydric alcohols. Any 8uitable polycdl~ylic acid may be used such as oxalic acid, malonic acid, succinic acid, glutaric acid, adipic 20 acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, brassylic acid, thapsic acid, maleic acid, fumaric acid, glutaconic acid, a-hydromuconic acid, B-IIYdL~ n; C acid, a-butyl-a-ethyl-glutaric acid, a, B-diethylsuccinic acid, isophthalic acid, terPrh~h;~l;,. acid, hemimellitic acid, and 1,4-Zs cycl~h~ An~d~c~r~oxylic ~cid. Any ~uit~le pol~ lric Qlcohol, " , ' 21898ql 5 ;n~ 9;ng both aliphatic and aromatic, may be used such aa ethylene glycol, propylene glycol, trimethylene ylycol, 1,2-h~tAnP~ , 1,3-bl~tiqnPr~ 1,4-butanediol, 1l2-ppntAnprl;nl, 1,4-pPntiqnp~ l, 1,5-pPntiqnPrl; ol, 1, 6-hP~iqnPrl; nl, 1, 7-heptanediol, glycerol, l, 1, 1-trimethylolpropane, 1, 1, 1-trimethylolethane, 1, 2, 6-hexanetriol, a-lO methyl glucoside, pentaerythritol, and sorbitol. Also included within the term "polyhydric alcohola" are ~ dç~ derived from phenol such as 2,2-bis(4-hydroxylphenyl)propane, commonly known as R; qphPn~-1 A. Preferred are diolg and triols for the manufacture of flexible polyurethane foams.
The hydroxyl-ct~nti~;n;n~ polyester may also be a polyester amide such as is obtained by ; n~ ; n~ some amine or amino alcohol in the reactants for the preparation of the polyesters. Thus, polyester amides may be obtained by rnn~lPn~; n~ an amino alcohol such as ethi~n-~l i nP with the poly~aLlJ~ ylic acids set forth above 20 or they may be made using the same components that make up the hydroxyl-cr~ntiq;n;n~ polyester with only a portion of the ~ llLs being a diamine such as ethylene diamine.
Any suitable polyoxyalkylene polyether polyol may be used such as the polymerization product of an alkylene oxide or a mixture of 25 alkylene oxides with a polyhydric alcohol. Any suitable polyhydric 218q8q~
alcohol may be used such as those disclosed above for use ln the preparation of the hydroxy-terminated polyesters. Any suitable alkylene oxide may be used such as those disclosed above for preparing the prepolymers. Polyethers which are preferred include the alkylene oxide addition products of trimethylolpropane, glycerine, propylene glycol, dipropylene glycol, and 2, 2 ' - (4, 4 ' -hydroxyphenyl) propane and blends thereof having efiuivalent weights of from 100 to 7, 000.
Suitable polyhydric polythioethers which may be condensed with alkylene oxides include the . ~ ; nn product of thiodiglycol or the reaction product of a dicarboxylic acid such as is disclosed above for the preparation of the hydroxyl-rf--~;n;n~ polyesters with any other suitable thioether glycol.
PO1YIIY~1LU~Y1--rfm~Aln;n~ phUh~UhUlUUh ~ L~f14 which may be used include those compounds disclosed in U. S . Pat . No . 3, 639, 542 .
Preferred polyllydlul~yl-cr~ntA;n;ng phosphorous compounds are prepared from alkylene oxides and acids of PIID~-UIIULUU8 having an acid equivalency of from about 72 percent to about 95 percent.
Suitable polyacetals which may be ~:u~d~lsed with alkylene oxides include the reaction product of ff)n~~l~Phyde or other 21898q 5 suitable aldehyde with a dihydric alcohol or an alkylene oxide such as those fl; Flrl ~78Pfl above .
Suitable aliphatic thiol8 which may be uulld~llse:l with alkylene oxides include alkanethiols rnntA;n;nrJ at least two -SH groups such as 1,2-ethanedithiol, 1,2-~Lu~c--le~ithiol, 1,3-propanedithiol, and 1,6-hexanedithiol; alkene thiola such as 2-butene-1,4-dithiol; and alkyne thiols such as 3-hexyne-1, 6-dithiol .
Suitable amines which may be uulldellse_ with alkylene oxides include aromatic amines such as aniline, o-chloroaniline, p-aminoaniline, 1,5-fl;i 'nr,nz~rhth:~lPnP, methylene fli~ P, the rr,nfl~n~At;rn product8 of aniline and formaldehyde, and 2,3-, 2,6-, 3,4-, 2,5-, and 2,4-diaminotoluene; ~l;rh~t;r amines such as methylamine, triisu~L"~ "l: nP, ethylPnPfl;: nP, 1,3-fl; ""l'LU~alle, 1,3-fl;: nnhlltzlnP, and 1,4-fl;: nnh~t~qnp~
Also, polyol8 rt~nt;l;n;n~ ester groups can be employed in the 20 subject invention. These polyols are prepared by the reaction of an alkylene oxide with an organic dicarboxylic acid anhydride and a compound rr~nt~;n;n'J reactive hydrogen atoms. A more comprehen3ive discussion o~ these polyols and their method of preparation can be found in U.S. ~?at. NOB. 3,585,185; 3,639,541 and 3,639,542.
" ~ 2189891 Polyols rrnt~;n;n~ graft polymer dlspersions may also be employed in the invention and are preferred. These are prepared by the in situ pol~. '7~tir,n~ in the polyols listed below, of an ethylenically unsaturated ~nomer or a mixture of ethylenically unsaturated monomers. Representative ethylenically unsaturated lC monomers which may be employed in the present invention include butadiene, isoprene, 1,4-r~n~ ;.onr, 1,6-h~ n~l;Pn~, 1,7-ort~ nf~, styrene, a-methylstyrene, 2-methylstyrene, 3-methylstyrene and 4-methylstyrene, 2,4-dimethylstyrene, ethylstyrene, isopropylstyrene, butylstyrene, phenylstyrene, cyclohexylstyrene, benzylstyrene, and 1~ the like; substitute styrenes such as cyanostyrene, niLL~I~LyL~lle, N,N-dimethylaminostyrene, acetoxystyrene, methyl 4-vinylbenzoate, phenoxystyrene, p-vinylphenyl oxide, and the like; the acrylic and substituted acrylic monomers such as acrylonitrile, acrylic acid, methacrylic acid, methyl acrylate, 2-hydroxyethyl acrylate, methyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, i80propyl methacrylate, octyl methacrylate, methacrylonitrile, ethyl a-ethoxyacrylate, methyl a-~r~t~m;nr,~rrylate, butyl acrylate, 2-ethylhexyl acrylate, phenyl acrylate, phenyl methacrylate, N,N-dimethylacrylamide, N,N-dibenzylacrylamide, N-butylacrylamide, :15 meth~crylyl ~on~mide, ~md the likej the vinyl e~ter~ yl 2 l 898~ ~
5 ethers, vinyl ketones, etc., such as vinyl acetate, vinyl butyrate, iGu~luu~ l acetate, vinyl formate, vinyl acrylate, vinyl methacrylate, vinyl methoxyacetate, vinyl benzoate, vinyltoluene, vinyl n5lphrh;l1 ene, vinyl methyl ether, vinyl ethyl ether, vinyl propyl etherg, vinyl butyl ethers, vinyl 2-ethylhexyl ether, vinyl 10 phenyl ether, vinyl 2 methoxyethyl ether, methoxybutadiene, vinyl 2-butoxyethyl ether, 3, 4-dihydro-1, 2-pyran, 2-butoxy-2 ~ -vinyloxy diethyl ether, vinyl methyl ketone, vinyl ethyl ketone, vinyl phosphonates such as vinyl phenyl ketone, vinyl ethyl sulfone, N-methyl-N-vinyl acetamide, N-vinyl-pyrrolidone, vinyl imidazole, 15 divinyl sulfoxide, divinyl sulfone, sodium vinylsulfonate, methyl vinyl F~l~l fnn~ , N-vinyl pyrrole, and the like; dimethyl fumarate, dimethyl maleate, maleic acid, crotonic acid, fumaric acid, itaconic acid, monomethyl itaconate, t-butyl 'nn~h methacrylate, dimehtylaminoethyl methacrylate, glycidyl acrylate, 20 allyl alcohol, glycol monoesters of itaconic acid, vinyl pyridine, and the like. Any of the known polymerizable monomers can be used and the ~ , J~ ds li8ted above are illustrative and not restrictive of the monomers suitable for use in this invention. Preferably, the monomer is selected from the group consisting of acrylonitrile, 25 ~tyrene and mixtures thereof.
The amount of ethylenically unsaturated monomer employed in the pol~ '7::1t;-1n reaction ig generally from 25 percent to 70 percent, pre~erably from 30 percent to 45 percent, based on the total weight of the product. The polymeri2ation occurs at a temperature between about 25~C. and 180~C., preferably from 80~C. to 135~C.
The unsaturated polyolb or macromers which may be employed in preparing the graf t polymer dispersion may be prepared by the reaction of any conventional polyol such as those described above with an organic compound having both ethylenic unsatura~:ion and a hydroxyl, carboxyl, anhydride, isocyanate or epoxy group or they may be prepared by employing an organic compound having both ethylenic unsaturation and a hydroxyl, carboxyl, anhydride, or epoxy group as a reactant in the pr~r~r~t~ nn of the conventional polyol. Re~LesellLative of ~uch organic ~ L~ include unsaturated mono- and polycarboxylic acids and anhydrides such as maleic acid and anhydride, fumaric acid, crotonic acid and anhydride, propenyl succinic anhydride, acrylic acid, acryloyl chloride, hydroxy ethyl acrylate or methacrylate and halogenated maleic acids and anhydrides, unsaturated polyhydric alcohols such as 2-butene-1,4-diol, glycerol allyl ether, trimethylolpropane .
5 allyl ether, pentaerythritol allyl ether, pentaerythritol vinyl ether, pentaerythritol diallyl ether, pentaerythritol vinyl ether, pentaerythritol diallyl ether, and 1-butene-3, 4-diol, unsaturated epoxides such as 1-vinyl-cyrlrlh~l~rnp-3~4-epoxide~ butadiene monoxide, vinyl glycidyl ether(1-vinyloxy-2,3-epoxy propane), 10 glycidyl methacrylate and 3-allyloxypropylene oxide (allyl glycidyl ether). If a polycarboxylic acid or anhydride is employed to incorporate lln~At~lrAt;nn into the polyols, it is preferable to react the llnRptllrAt~l polyol with an alkylene oxide, preferably ethylene or propylene oxide, to replace the carboxyl groups with 15 hydroxyl groups prior to employment in the present invention. The amount of alkylene oxide employed is such as to reduce the acid number of the unsaturated polyol to about 5 or less.
Illustrative polymerization initiators which may be employed are the well-known free radical types of vinyl polymerization 20 ;n;t;Atnrg guch ag the peroxides, persulfates, perborates, Pt:L~ t~ azo , ,~uu~ld~ etc. These include hydrogen peroxide, dibenzoyl peroxide, acetyl peroxide, benzoyl l~ydlu~u~lw~ide~ t-butyl llydLu~eluJLide~ di-t-butyl peroxide, lauroyl peroxide, butyryl peroxide, diisopropylbenzene h~ uu~lu~ide, ZS cumene h~uy~u~de, par~menth~ne hyd~ y~ de~ di.~cety1 , ; , .
2~89891 5 peroxide, di-a-cumyl peroxide, dipropyl peroxide, diisopropyl peroxide, isopropyl - t -butyl peroxide, butyl - t -butyl peroxide, difuroyl peroxide, bis (triphenylmethyl) peroxide, bis (p-methoxybenzoyl) peroxide, p-monomethoxybenzoyl peroxide, rubene peroxide, ascaridol, t-butyl ,uuLu~yb~ zoate, diethyl peroxyterPph~h;ll ~te, propyl hydLu~e~ u~ide, isopropyl hydluu~lu~Llde, n-butyl hydlu~u~:L,.~lde, t-butyl hydlu,u~:lu~lde, cyclohexyl hydLu,u~Lu~ide, trans-decalin IIYdL~I~UP~ 1PI a-methylbenzyl hydluL,~ Lide, a-methyl-a-ethyl benzyl lly~Lu~ueLu~idel tetralin hydLuuuLu~Lide~ triphenylmethyl hydLu~uelu~ide, diphenylmethyl llydlu~u~lu~ide, a,a'-azobis-(2-methyl heptonitrile), 1,1'-azo-bis (cyclohexane carbonitrile), 4, 4 ' -azobis (4--:y,lllu~uullLanoic acid), 2, 2 ' -azobis (isobutyronitrile), 1-t-butylazo-1-cyanocyn1 nhP~r;qnP, persuccinic acid, diisopropyl peroxy dicarbonate, 2,2'-azobis(2,4-dimethylvaleronitrile~, 2-t-butylazo-2-cyano-4-methoxy-4-methylpentanel2l2l-azobis-2-methylh~l~Anpnitrile~ 2-t-butylazo-2-cy~nnh~lt~np, 1-t-amylazo-1-cyanocyclohexane, 2,2'-azobis(2,4-dimethyl-4-methoxyvaleronitrile, 2, 2 ' -azobis-2-methylbutyronitrile, 2-t-butylazo-2-cyano-4-methylpentane, 2-t-butylazo-2-i~locutyr~nitrile, to butylpero y _ropyl ~Arhr~n~t~ an~ the likej a mixture of initiators may also be used. The preferred initiators are 2, 2 ' -azobis (2-methylbutyronitrile~, 2, 2 ' -azobis (isobutyronitrile), 2, 2 ' -azobis (2, 4-dimethylvaleronitrile), 2-t-butylazo-2-cyano-4-methoxy-4-methylpentane, 2-t-butylazo-2-cyano-4-methylpentane, 2-t-butylazo-2-cyano-butane and lauroyl peroxide. Generally, from about 0.1 percent to about 10 percent, preferably from about 1 percent to about 4 percent, by weight of initiator based on the weight of the monomer will be employed in the process of the invention.
A particularly preferred polyol for use in the instant invention will be a graft polyol having from 5 to 60 percent vinyl, the monomer being comprised of a mixture of acrylonitrile and styrene, in a carrier polyol having a number average i l~clllAr weight of from 2000 to 10, 000. The carrier polyol will preferably have a tr; f-lnr~ n~l initiator and contain at least 5 percent ethylene oxide, most preferably a 5 to 60 96 E0. However, it will be appreciated that while not preferred, the use of carrier polyols having no E0 is within the scope of the invention.
A most preferred graft polyol will have from 10 to 50 ~6 of a mixture of acrylonLtrile and styrene in a carrier polyol having an initiator selected from the group consisting of trimethylolpropane . , , 2~89~91 5 and glycerine, arld a ilumber average, ~ Flr weig~lt; o~ ~on~ 300 to 7000. ~'he ~arrier polyc~l wi}l pre~era~1y contain L0 I;o 30 % ~30.
A~ ;n~ I Pr1 above, tlle polyol componellt will ~18~1ally al~o contain a uret~lane promotin~ cata.ly3l alld e~ blowillg ay~ t.
~ ny sui~:.able urQ~arle prom~ lg cal;aly3t may be u~~e~ rJ ~
10 tertiary alnine~ h ~, for exall~ple, triethyl,anPAii 'Tl~, N-methylmvLp~lolille, N-~t~lylm~rp~lolille, ~ie~.ilyleth ~nl; n~
C ~IIJ1irle~ eth~1 4_dime~h~ rI~Pr~Y1PiPerZ~Zine~ 3-metl~ y~ yldi~ t~lylanlinel ~,N,~'-trimetl~yli~opropyl propylPn-"l;. n~, 3-diet}-ylami!lopropyldieti~yla~nine, 15 dimethylbe~zyla~nirle, ~md ~lle like~ ~ther sui~able cataly~.ts are, i~o~ e~can~ple, 3tal~rl0u3 ch~oride, dibutylt~l di-2-e~lyl }IP~Tl~te~
~italmous vxide, a~s well ~s ot}le.r ~L' . . t~ compoundE ~uch ~s are disalosed in U.S. Pa~. ~o. 2,8~6,40~.
8ui~able blowing aye~lts illclude water, chen~i~ally inert, low ~0 boili~lg, ~Iy~ro~arbons and halogenated ~ d-v~a-l~OIIs alld mixtures t~lereof. E:xampLes o~ the la~er i.nclude t~lo~,e having boil.illy points below 50 degrees C and pIe~erably bet:ween -50 C aIId 30 C at atmospheric pressure.
Illu3trative e~ les Or ~iuitable blo~irly ayentb are haloyena~ed 35 h~ Oh v~3 n~ ~cl-lolodl~
.. . .
dichlo~ nromethane, dichlorofluoromethane, and trichlorofluoromethane and their mixtures, and h~dLuuaLbull5 such as propane, n-butane, and isobutane a~ well as dimethyl ether and cyclopentane, acetone and formic acid.
However, in general, water is the most preferred blowing agent 10 for use with the instant invention.
In any case, it is neces8ary that the blowing agent be present in an amount sufficient to be r~rnn~;hl~, at a minimum, for at least 95 percent of the expansion of the polyurethane foam.
However, it is preferred that the blowing agent be responsible for 15 essentially all or at least 98 percent of the expansion of the foam. Most preferably, the blowing agent will be responsible for 100 percent of the PYpAIl~; nn of the foam.
In any event, no expansion of the foam 8hould be the result of the inert gas injected into the ,~ streams. Those skilled 20 in the art will appreciate that the required quantities of blowing agent can be determined experimentally as a function of the desired density and amount of the foam, A3 ;n~i;r2~-~fl aoove, optional elements or additives of the polyol . .~ stream can include surfactants, chain ~ n~nrl~rp~, 25 flame-inhibitors, An~;n~ n~, lnorganic and organic acids, . ~
5organic f illers, pigment3 and colorants, antistatic additives and mixtures thereof.
Chain-~t~nrl;n~ agents which may be employed in the preparation of the polyurethane foams include those ~ ds having at least two fllnr~;nn~l groups bearing active hydrogen atoms such aa water, hydrazine, primary and secondary diamines, amino alcohols, amino acids, hydroxy acids, glycols, or mixtures thereof.
Such agents will generally have a number average I 1 Pr~ r weight of less than about 400. A preferred group of chain-l~ on~l;n~
agents includes water, ethylene glycol, 1,4-b~tt~n~-~;nl and primary and secondary diamines which react more readily with the prepolymer than does water 6uch as phenylene diamine, 1,4-cyclohexane-bis-(methylamine), ethylf~n-~A;, nr, diethylenetriamine, N- (2-hydroxypropyl ~ ethyl F~n.,~1;; nP, N, N ' -di ( 2 -hydroxypropyl)ethylon~; nP, piperazine, and 2-methylpiperazine.
A surface-active agent is generally necessary for production of high yrade polyurethane foam according to the present invention, since i~t the absence of same, the foams generally collapse or contain very large uneven cells. Numerous surface-active agents have been found satisfactory. Nonionic surface-active agents are preferred. Of these, the nonionic surface-active agents such as 5 the well-known silicones have been found particularly desirable.
Other surface-active agents which are operative, although not preferred, include paraffin oils, castor oil, turkey red oil, polyethylene glycol ethers of long chain alcohols, tertiary amine or ;~lk~nnl: 'nP salts of long chain alkyl acid sulfate esters, 10 alkyl sulfonic e~ters, and alkyl arylsulfonic acids.
Among the flame retardants which may be employed are pental,L~ '; rhPnyl oxide, dibL~ , u~allul, tris ( 5-chloropropyl)pho8phate, 2, 2-bis (bromoethyl) 1, 3-propanediol, tetrakis(2-chloroethyl)ethylene fl~rhr~rhA~P, tris(2,3-15 di~L~ , u~yl)phosphate, tri~(:3-chloroethyl)rhr~ph~pl tris(l,2-dichloropropyl)rhr~rh~e, bis- (2-chloroethyl) 2-chloroethylpllo~ ul.ate, molybdenum trioxide, . ~ molybdate, ammonium phosphate, pentabL~ lrhPnyloxide~ tricresyl phosphate, hexabromocyclododecane, melamine, and dibromoethyl-20 dibromocyrl~h~ np~ The concentrations of flame retardant compounds which rnay be employed range from 1 to 100 parts per 100 parts of polyol mixture.
The isocyanate and polyol r~-nt~;ninrJ component streams will generally be introduced into polyurethane foam making machine such 25 as are well known to those skilled in the art. Machines -5 particularly suited to the production of ~lexible polyurethane slabstock foam are particularly preferred. Illustrative examples are the M-30 Lab Machine and the ~ennecke U~sT-63. Through machines are well-known in the art and are described, for example, in IJ.S.
Patent 4, 074, 960 and 4, 298, 557 .
The inert gas to be injected into the isocyanate and polyol ~-nn~;l;n;n~ streams will generally be of a type which will not react with the polyurethane ~ ~J i,.." .,l R, such as inert gases or noble gases. Illustrative examples include air, carbon dioxide, nitrogen, or argon. Preferred gases are carbon dioxide and nitrogen. Carbon dioxide is most preferred.
The amount of inert gas to be injected will be incapable of producing any measurable ~ nc;~-n of the flexible polyurethane slabstock foam. That is, the amount injected should be capable of producing only negligible ~ nR;~-,n of the foam, if any.
The inert gas may be injected into one or both of the gtreams. In general, the gas will be injected into that -n~ stream which exhibits the greatest solubility for a particular gas. The gas may also be injected into the combined streams of ~ , R, ~ In general, the amount of inert gas to be in; ected will be 0.0010-l.o weight percentage of the selected ~, ' stream.
In~ection into isocyanate stream is most pre~erred. E~or example, it is preferred to have inert gas injected at 0 . 0050-0 . 750 weight percent of the isocyanate ~ L~ t stream. Most preferably, inert gas will be injected at an amount of 0.010-0.50 weight percentage of the isocyanate. The isocyanate amount will be based upon 100 parts by weight of the polyol - ~ stream.
The location of inj ection will vary depending on a variety of factors 8uch ag machine type, metering and mixing Pr~ ', polyol 15 selection and isocyanate selection. In general, the gas will be injected into the selected stream at a location facilitated by the machine design. Examples of suitable in~ection locations include the ~, manifold on a pour head, the suction side of a high shear or h~ " 7; n~ pump inline with the polyol stream, and the 20 suction side of a high pressure polyol and/or i~ocyanate pump.
In general, the inert gas is inj ected with the aid of a hypodermic needle, such as an 18 gauge No. 2 point type.
The solubility of the inert gas in the selected stream or streams may be effected by a variety of factors.
"' .
5 Generally, it is desirable to increase the ~nl~lh;lity of the inert gas in the selected ~ _ stream(s).
It has been found that factors such as _ stream ILes~uLès and ~ _ t ~ 8, inert gas pressure and t _ dLul~, head pressure and mixer speed may play a role in the effectiveness 10 of the injected inert gas and thus on the final rh~r~rt~r; ~tics of the r~ lt;n~ foam. (~ _ and gas ~L~suLt~8 and ~, cLLuL~:s will generally depend on the identity of the particular or gas used, as well ag the type of foam production Pq~l;
; 1 i 7~
Similarly, the ~ c~inn of an optimum head pres8ure and mixer speed will also depend on the same factors. However, as ~' LLaLed in the following working examples, it may be stated that head pressure should be ~-;n~;nP~l at a range of between 5 to 30 psig. TnrrPA~; ng the mixer speed was also found to have a 20 rlP~;r~h~P effect on the final foam obtained. Those skilled in the art, however, will appreciate that head pressure and amount of mixed speed are related.
Tho8e skilled in the art will appreciate that ultimately, either before or after the injection of the inert gas, the 25 isocyanate and polyol rnn~;~in;n~, ' stream8 will be brought together 80 as to facilitate a reaction tht:L~ L-~ccn. The length of reaction time will depend on the selection of the particular llLs selected and the foam production e~ utilized.
However, illustrative free rise reaction times with respect to typical slabstock tl;cp~nc;n~ eguipment are 12 to 20 seconds for 10 cream time and approximately 1 to 3 minutes for rise time.
Flexible polyurethane slabstock foams produced ~-rnr~1ing to the invention exhibit an optimum, ' n~t;nn of feel, comfort and wear characteristics It is believed that these attributes will be possessed by foamg having (a.) a particular cell gize dig~r;h~1t-nn, 15 (b. ) a particular catastrophic fatigue value, and (c . ) a particular visual appearance.
While not wishing to be bound to a particular theory, it is believed that cell size dis~r;hu~;nn i8 particularly relevant to the achievement of optimum comfort and wear characteristics in 20 flexible polyurethane slabstock foams.
Cell size distribution is intended to refer to both the size of the cells and the number of each size of cell present i~ a cro8s section of the foam. Terms such as fine and coarse L~L~8c!llL t~e ends of a spectrum which generally relates to the size of the 25 cells, while random and uniform often refer to the end points of a ' ~
5 spectrum referring to the number of certain sized cells present in a cross section of the foam. Those skilled ln the art will appreciate, however, that with respect to cell ~ize, the particular numbers may be somewhat d~t!lld~ lL upon foam type and composition.
In general, fine cells are preferred over coarse cell8 when 10 optimi7~;nn of p~Lr~ e properties such as fatigue, tensile strength, tear strength, elongation and support factor are desired.
With respect to the most preferred foams of the invention, fine cells may be defined as those having a maximum diameter of 1.0 mm, while coarse cells can loosely be termed as those having a 15 diameter greater than the maximum diameter for fine cells.
Random cell structures will be those wherein no one cell size range (ie., cells having a diameter which is within ~ or - 10096 of the average cell diameter) constitutes a majority of all visible cells in a cross section of the foam. Uniform cell structures 20 will be those wherein a majority of the visible cells are within a particular cell size range. It ig currently believed that optimum wear characteristics are obtained with random structures.
E~owever, while foam6 which may be characterized as both fine and random are believed to be preferred, it is possible that a foam .~
5 capable of only one such ~hArA~tPr;7~tirn may exhibit the superior properties of the claimed polyurethane cl ~hctn~-k foam.
DPc~;rAhlp foam8 will generally be those having a cell bLLucLuld such that at least 1096 and preferably 2096, of the cells visible in a crogs gection of the foam are within a common cell 10 size range. Preferably, said 10% of cells will have a diameter of at least 0.1 mm.
More particularly, with re8pect to the most preferred foam of the invention, it is believed that in general, at least 90 percent of the cells present in a cros8 section of the foam 8hould have a diameter between 0.1 and 1.0 mm. Preferably at least 75 percent of the cells will have a diameter between 0 . 2 and 0 . 8 mm. Most preferably, at least 40 percent of the cell8 will have a diameter between 0.3 and 0.6 mm.
~ Ptprm;nAt;r~n of cell size distr;hl~t;~n may be done either 20 manually with a 8tereo microscope and a grid or inbLl ' ~lly using a " ' Pr; 7PCI video imaging and ~lltl ~ Prl cell counting system. Cell cize counts may be given as cells per- inch ~cpi) or as a r ~ of cell size diameter in m;ll; Prc.
Optimum wear ~h~r~rtPr;ct;r~c are exemplified by certain 25 rs~t;~ctrt~rh; c fatigue values . A8 used herein, catastrophic fatigue ~ 2 1 8~89 1 5 is defined by two testing parameter6, both resulting from ASTM test D3574(40k cycles, no carpet). First, the percent 1088 in height is measured~ It should be no more than 10~~, with less than 5~ lost being preferred, and less than 296 lost being most preferred.
Second, the 9~ hardness retained at 65'6 IFD ~f~pct;~n should be at least 509f, with at lea6t 609~ being preferred and at least 65~6 being most preferred.
Finally, the performance and comfort characteristic are also ;n~ PnrPcl by the vigual appearance of the foam. That is, the foam should be 8ubstantially free of large voids, which may be 15 classified by the size of their diameter8. As indicated previously, voids having diameters of from lmm to 3mm are defined a~ buckshot, while voids having diameters of from 3mm to 6mm are peahole8. It is desirable that the foam be substantially free of peaholes. By "substantially free" it is meant that the foam have 20 no more than 1 to 2 peaholes per square meter.
The invention is further illustrated, but is not intended to be limited by the following examples in which all parts and percentages are by weight unless other~qise specif ied .
E~l~
ZS he iollowing :~ ~rial~ wer; u~ed in the ewanple~ below:
,~ , Polyol A is a graft polyol commercially available from BASF
Corporation of ~yandotte, Michigan, PLURACOL~ Polyol 1231 D; ~th;lnnl; n~ LF is a produce of VAN WATER & ROGERS Inc.
DC-5164 Silicone surfactant iB a product of AIR PRODUCTS
DABCOr 33LV Catalyst is a product of AIR PRODUCTS
DABCo'9 T-12 Catalyst i8 a product of AIR PRODUCTS
ANTIBLAZl~l 100 is a product of ALBRIG~IT ~ WILSON
Iaocyanate B is a mixed isocyanate commercially available as LUBR~NATE~ No. 236 ISO from BASF Corporation.
All urethane ~ ,~ulle~lLs were metered in separate streams into a pin-mixer type low pressure pour-head which then dispensed the reacting mixture onto a moving conveyor. The dispensed li~uid mixture at a prescribed time began to cream then expand, shaped by the moving conveyor and static side wall8. This rnnt;n~lml~
reacting foaming operation was allowed to run until a 15-foot block of foam was made. The foam block was allowed to cure for minimum 72 hours at ambient r~n~l;t;nn~ after which standard test pads were cut for physical ~!L~ L~y testing.
Foam blocks were prepared with Polyol A and Isocyanate B at 110 index using a 2.1 pbw water f l;~t;nn and related ancillary , ~ are listed in Table 1:
.
E~T.~TTnN, ~bw = 1 2 Polyol A 100 . 0 100 . 0 100 . 0 Water Added 2.1 2.1 2.1 ni~th;~n~ ' n~ LF ~ ~ 7 ~ ~ 7 ~ ~ 7 DC-5164 Surfactant 1.5 1.5 1.5 DA}3COl 33LV 0.15 0.15 0.15 DA13CO~ T-12 0.1 0.1 0.1 ANTIBLAZE~ 100 3 . 0 3 . 0 3 . 0 Isocyanate B (110 40.5 ~ 40.5 40.5 Index) ~~q.~ rr'_TT.TnN.C~ -Injection Point Isocyanate-----~ -------->
Nucleating Gas Type N2 CO2 CO2 Gas Flow Rate, L/min . 3 . 4 3 . 2 4 . 0 Gas Temperature, ~F 71 71 71 Gas Pressure, psig 10 10 20 Wt . of gas in iso 0 . 05 0 . 07 0 .12 stream, ~
Pour Head Pres., psig 10 10 7 Iso Inject. Pres., 400 500 500 psig F~" P~u~
Density, PCF 3 .1 2 . 9 3 .1 IFD, lbs 91 129 116 Support Factor 2.45 2.07 2.48 Air Flow, CFM 0.4 0.2 0.4 Cata~trophic ~atigue 40k cycles no carpet Height, 96 loss 1.3 8.4 1.8 6596 IFD96 hard . 81. 5 38 . 5 80 . 7 Retained 2 ~ 8989 1 Visual D~R rri rt i nn Cell Size Random Uniform Random Pore ~rr~ArAnr~ TrrPrJlll Ar .Crhl~r; r il Trr~rJlll Ar Average Cell Diameter, 0.42 0.~6 0.45 mm Cell Diameter Range, 0.14-0.75 0.30-0.60 0.18-0.95 mm Cell Count Per Inch 75-70 63-58 73-68 ~Cell - ~ made with RAM Optic ArrArAtllC
Comparing f~ lAt;nn 1 with 3 ;n~l;rAtF~l that foams J~l~rloAt~
with either N2 or COI gave a similar cell pattern and fatigue lO properties. The fatigue rPrfnrr~nr~ of fl lAt;nn 3 was improved over f~ lAt;nn 2 due to ;nrr~Acer3 . .".rr~ ..1 ;nn of C0~ in the isocyanate stream and lower pour-head pressure. The foam produced with fl lAt;nn 3 with CO2 n~lrl~At;nr; gas had ~;gTl;f;r;mtly reduced number of defects in comparison with the one produced with fl 1i3t;nn 1 uging N, gaa. Phntn~rArhç: of these foams at 23x --~n;f;r?t;nn are attached aa Figurea 1, 2, and 3. Figure 1 illllS~trAtf~q foam 1 with defectg, Figure 2 illustrates foam 2 without defects and Fi ,ure 3 ;llllCtrAt~c foam 3 without defects.
It should be u-ld~ Dl,o~J'i that while the invention as shown and 20 described herein ;lll~~trAtPq currently prF~frrr~ - c of the invention, it is not intended to illustrate all possible forma thereof.
218~891 , 5 A variety of polyull:LIIalle foams can be created by one of ordinary skill in the art without departing from the spirit and scope of the invention disclosed and claimed.
E',r.~8rTRT,I;~ pr~T.~!l~l~t;rR ,qT.l~R 5Tt-rT~ Fl'~AM ~TAV,TNa S~pT'T~T-~ FTIT~T., CQ~5FORT, ~ W~AT~ r~T~T ~rTRTlTCTIrC
PiPl-l of ~hP InvPntinn The present invention provides a flexible polyurethane slab stock foam having superior feel, comfort, and wear characteristics, a process for making the same, and a method of reducing the number of defects in a polyurethane foam, wherein the defects have a diameter which is at least four times greater than the common cell 20 size.
More r~rti c ~ rly, the invention relate8 to a polyurethane slab stock foam characteri2ed by (a. ) a cell size distribution wherein at lea8t 20 percent of the cells visible in a cross-section of the foam have a diameter of at least 0.1 mm, and (b.) a 25 substantial absence of cells having a diameter which is at least four time8 greater than the common cell si2e diameter. The foams of the invention are further definaole as having a catastrophic fatigue value rh~r~n~,orized by (1) a percent 1088 in height of no more than 10 percent, and (2) a percent hardness retained (65 30 percent IED) of no less than 50 percent.
' ~ 2189891 Backgrrl~n~ of th~ TnV~nt;nn The production of high quality flexible polyurethane slab stock foam has long been a goal of the polyurethane foam industry.
Slab stock foam physical ;Ittr;h~c~c are defined under ASTM D3574 and D3770 6tandard specifications for Flexible Cellular ~-tPr;;~lc ;nrl.-~;n~ but not limited to conventional, high resilience, and combustion modified high rpc;l;onrf~ polyurethane foam. Carpet cu6hion foam standards are spPr;f;f~rl in but are not limited to E~UD
UM72a. Foams having optimum levels of feel, comfort and wear 15 characteristics as well as a desirable visual d~ L~ e:, have been particularly difficult to achieve.
The performance re~uirements of some end uae Prpl;rAt;nnc have been ~r~r;~11y challenging. For example, carpet cushion has particularly rigorous performance rer~uirements which have been 20 difficult to achieve while ~-;n~;n;n~ a balance of the other desirable properties.
High r~uality carpet cushion should have a plush or pleasantly soft feel to the touch. Optimally, those skilled in the art would like a user of the carpet cushion to experience a sinking or 25 floating feeling when walking or r~sting upon the cush~on.
In addition, high quality polyurethane foam carpet cushion must simultaneously eYhibit both short term and long term resistance to compression and the results of repeated use. The foam muat not "bottom out" or give way under successive every day use .
Also, the carpet cushion must eYhibit improved wear characteristics with respect to both itself and the wear of any carpet used thereon. That is, the cushion must serve to improve the long term performance of the carpet and thus must not hasten carpet degradation with undesirable wear of the carpet cushion 15 itself.
~ inally, the carpet cushion must be visually ~E~PP~l ;n~ to both wholesale and retail l_:U112~ . In particular, high quality slab stock polyurethane foama intended for use as carpet cushion must be substantially free from visible defects. ~Y---;n~t;nn of a cross-20 section of traditional slab stock foam will generally reveal thepresence of voids which can be defined in terms of their diameter.
The perception of what constitutes a void is to some eYtent ~p~n~Pn~ upon the gize of the cells which prf~ n~ in the foam, i.e. common cell size diameter. Common cell size diameter may be 25 defined as the average diameter of the most prevalent cells which , have a diameter which i5 within + or - 10096 of each other.
Preferably, the common cell size diameter will be the average diameter of those cells which have a diameter which i8 within + or - 5096 of each other. Most preferably, the common cell size diameter will be the average diameter of the most prevalent cell6 having a diameter which i8 within + or - 309~ of each other.
For example, in foams having a common cell size of 0.5 mm, cells having a diameter of from 1 mm to 3 mm would generally be viewed as a defect called buckshot, while cells having an average diameter of 3 mm to 6 mm would generally be defined as a peahole defect. In general, a defect may be defined as a void apparent in a cross section of a foam which has a diameter which is at least four times greater than the common cell size diarneter. Preferably, t~le foams of the invention will have a substantial absence of voids having a diameter which is at least three time greater than the common cell size diameter. Most preferably, the foams of the invention will have a substantial absence of voids having a diameter which is twice that of the common cell size diameter.
Defects generally arise as a result of the entrapment of air and high viscosity ~ during the formation of the foam~
25 Alr entra1 sd in th~ ~reth~e ~ = dur1n~ tr~na~r to u~d ' ~ 2~89~91 5 from storage vessels and metering ~ ;rmPnt, plus inconsistent processing habits are believed to be possible causes of foam def ects .
Thus, it is an object of the instant invention to provide a flexible polyurethane slab stock foam which has superior feel, 10 comfort and wear characteristics and which has a substantial absence of cells having a diameter which is at least four times greater than the common cell size diameter.
It is another object of the invention to provide such foams which also exhibit fatigue values characterized by ~1) a percent 15 loss in height of no more than 10 percent and (2) a percent retained (65 percent IFD) of no less than 50 percent.
Finally, it is an object of the invention to provide a process of making such foam as well as a method of reducing the number of defects in polyurethane foam wherein such defects have a diameter ~0 which is a least four times greater than the common cell size.
S11mm~rv of the Inv~ntion The foregoing ob~ect and more are achieved with the flexible polyurethane slabstock foam of the invention. Such foam results from a process of making wherein a stream of an isocyanate ~ nt~;n;n~ llt is provided along with a stream of a polyol 2 i7 89~9. 1 , 5 L , ' having a blowing agent which is r~7r~7n~7;hle for at least 95 percent and preferably, 100 percent, of the l~r;7n~7;~n of the foam. An amount of an inert gas is injected into one or more of the isocyanate or polyol ~ ~ streams, the amount of injected gas being capa~le of producing only negligible P~r 7nq; ~m of the 10 foam. The isocyanate and polyol ~ _ streams are reacted together for a time 8ufficient to produce a polyurethane foam. The resultant polyurethane slab stock foam is ~ h;7r;7rt~ri 70~7. by (a. ) a cell size distr;h77t;~7n where at least 20 percent of the cells vi8ible in a cross sectio7~ of the foam have a diameter of at least 15 0 .1 m!n, and (b. ) a substantial absence of cell8 having a diameter which is at least four times greater than the common cell size diameter. me resulting foam is further ;r7.ont;7~ 7. by a catastrophic fatigue value r h~7r~7~ t~r7 7~7 by (1) a percent 1088 in height of no more than 10 percent and (2) a percent retained (65 20 percent IPD) of no less than 50 percent.
me invention also provides a method of reducing the nun7ber of defects in polyurethane foam wherein the defects have a diameter which is at least four times greater than the common cell size diameter. The method involves the provision of a stream of an 1rocyrpate r~nt/ll~;n~ r, rP the provi~li~ Or a rtrer Or 1-" ~ 2189891 5 polyol component having a blowing agent which is r~rnn~ihl e for at least 95 percent of the ~ n~; nn of the foam. An amount of inert gaa ia inj ected into one or more of the iaocyanate or polyol nn~nt gtreams, the amount inj ected being capable of producing only negligible expan6ion of the foam. The streams are reacted ~0 together for a time sufficient to produce a polyurethane foam.
Descr;~tion of the Draw;n,r~:
Figure 1 is a cross sectional photographic view of a prior art foam having a defect therein.
Figure 2 is a cross sectional photographic view o~ a foam of 15 the invention having 6ubatantially no defects.
Figure 3 ia a cross ~l~rt;nn~l photographic view of a second foam of the invention having substantially no defects.
De~ orl Deacr; ~tion of the Invention The flexible polyurethane slab stock foam of the invention 20 exhibits superior feel, comfort and wear characteriatics. It iB
obtained from a particular procesa of making which requires the inj ection of an amount of inert gas into one or more isocyanate or polyol CU...,~ steams. The amount of inert gas injected is capable of producing only norjl; g; hl e, if any, ~n~; nn of the 25 foam .
2 1 8989 ~
The stream of an isocyanate cnn~;n;n~ U~ lt will generally be comprised of one or more organic isocyanates. Organic polyisocyanates suitable for use in the instant invention ~:ULL~#~Vlld to the formula R' (NCO) z wherein R' is a polyvalent organic radical which is either aliphatic, arylalkyl, alkylaryl, aromatic or mixtures thereof and z i5 an integer which ~uLLc:#~ulld8 to the valence of R' and is at lea8t 2.
Representative of the types of organic polyisocyanates ntP~r~rli~ herein include, for example, 1,2-diisocyanatoethane, 1, 3-diisocyAn~tnrror~AnP, 1, 2-diisocyanatopropane, l, 4-diisocyanatobutane, 1,5-diisocyanatopentane, 1,6-dissocyanatohexane, bis (3-isocyanatopropyl) ether, bis (3-isocyanatopropyl) sulfide, 1, 7-dii80cyanatoheptane, 1, 5-diisocyanato-2,2-dimethylpentane, 1,6-diisocyanate-3-methu~yl~ a~ld, 1,8-diisocyanatoctane, 1,5-diisocyanato-2,2,4-trimethylpentane, l,9-diisocy~n~r-- , l,10-diisocyanatopropyl ether o~ 1,4-butylene glycol, l,ll-diisocy~n~tmlntlPr:~np, 1,12-diisocy~n~tr~nflPr;~nf" bis(isocyanatohexyl)sulfide, ,4-diisocyanatobenze, 1,3-diisocyanato-o-xylene, 1,3-diisocyanato-p-xylene, 1,3-diisocyanato-m-xylene, 2,4-diisocyanto-1-chlorobenzene, 2s 2,4-diiaocy~nato 1 nitro b~n~ene, 2,5 dli~o y~n:to-l-nlLLu~ e~
21898ql S m-phenylene diisocyanate, 2,4-toluene diiEocyanate, 2,6-toluene diisocyanate, mixtures of 2,4- and 2,6-toluene diisocyanate, 1,6-hexamethylene diisocyanate, 1, 4-tetramethylene diisocyanate, 1, 4-cyr1~hPlr~nP diisocyanate,hexahydrotoluene diisocyanate, 1,5-naphthalene diisocyanate, 1-methoxy-2,4-phenylene diisocyanate, lO 4,4'-cyclohexane diisocyanate, hexahydrotoluene diisocyanater l,S-n;~rh~h~lPnP diisocyanate, 1-methoxy-2,4-phenylene diisocyanate, 2,4'-4,4'-diphenylmethane diiEocyanate, 4,4'-biphenylene diisocyanate, 3,3'-dimethyl-4,4'-diphenylmethane diisocyanate; the triisocyanates such as 4,4' ,4"-triphenylmethane triisocyanate 15 polymethylene polyphenylene polyisocyanate and 2,4,6-toluene triisocyanate; and the tP~r~;Rrryanates such as 4,4'-dimethyl-2,2'-5, 5 ' -diphenylmethane tetraisocyanate.
The polyisocyanates are prepared by conventional methods known in the art such as the phoE~n~ n of the corresponding organic 20 amine or equivalent processes.
Included within the useable isocyanates are the modifications of the above isocyanates which contain r~rhr,tl1;m;rlP, Alloph~1n~te or isocyanurate structures. Uretr,n;m;nP-carbodimide derivatives of PRRPn~ l l y pure diphenylmethane diisocyanate can be made by well-25 known techniques, such as the conversion o~ a portion of the 21 89~9 1 , 5 isocyanate groups in diphenylmethane diisocyanate to a carbodiimideby using a phosphorus-rnnt~in;ng catalyst at elevated temperatures, and then allowing the r~rhn~9;;m;-1~ modified diphenylmethane diisocyanates to further react with unreacted isocyanates groups to form urPtnn;m;n~ modified MDI. The conversion from r~rhnr~;;m;rlo 10 modified MDI to uretonimine modified MOI does not typically go to completion, having a composition ~ nnt~;n;n~ small amounts of ~ rhn.l;;m;~,, groups. Typically from about 10 to 35 percent by weight of the ~I as converted to urPt~n;m;nP-~rhnrl; ;m;~P modified MDI species leaving from 65 to 90 percent of the MDI unreacted.
PrepolymerY and quasi-prepolymers may also be employed in the process of the subject invention. These prepolymers ~uasi-prepolymers are prepared by reacting an excess of organic polyisocyanate or mixtures thereof with a minor amount of an active hydrogen-~-nnt~;n;n~ compound as determined by the well-known 20 Zerewitinoff test as described by Kohler in Journal of the American Chemical Society, 49, 3181 (1927). The3e ~ ,,uulLds and their methods of preparation are well known in the art. The use of any one ~pecific active hydrogen compound is not critical hereto, rather any such compound can be employed herein. Generally, the 25 qua~i-prepolym~r~ have a ~ree l~oc ~at- content ~e erom 2~ per~ent , 5 to 40 perce~t by weight while prepolymers will have a free isocyanate content of from 2 to 15 percent by weight.
Especially useful due to their avA; l ~h; l; ~y and properties are toluene diisocyanate, 2,4'-diphenylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate, polymethylene polyphenylene lO polyisocyanate, modified isocyanates .as described above, and mixtures thereof.
However, it has been found that the preferred isocyanate f~nn~i~;n;n~ ~nmrnn~n~ will be comprised of mixtures of diphenylmethane diisocyanate (MDI) isQmer5,, 'lfi~-1 isocyanates 15 ~nnt~ln;n~ ure~nnP;m;n~ r;lrhQ-l;;m;~, allophanate and/or isocyanaurate structures, and toluene diisocyanate (TDI)~
A preferred MDI isomer is 4,4'-diphenylmethane diisocyanate.
Preferred modified isocyanates will generally have from 5 to 50%
carbodiimide, with 10 to 3096 being most preferred. While any 20 suitable TDI may be used, such as 2,4-TDI or 2,6-TDI, mixtures c~nn~;~;n;n~ from about 65 to 85 percent 2,4-TDI and the balance 2,6-TDI are preferred. A particularly preferred isocyanate rnnt~;n;n~
~ , -' will comprise from 20 to 95 weight percent 4,4-MDI
isomer, 1 to 60 weight percent ~ ~;fi~-7 isocyanate, and 1 to 60 25 weight per~ent TDI.
~ 218~91 The most preferred isocyanate ~~nnt~;n;n~ . ~n~ will comprise from 30 to 80 weight percent 4,4'-~I, 5 to 50 weight percent r 'ifi.~rl isocyanate, and 5 to 50 percent TDI.
The stream of polyol, ,lu~ llL may also be termed the resin side or isocyanate reactive ~nmrnn_n~ This ~ ~UIl~ will generally be comprised of a blend of a polyol, a urethane promoting catalyat, a blowing agent, and optionally, one or more additives selected from the group consisting of surfactants, chain extenders, flame ;nh;h;t-nrs~ An~;nY;~n~R~ and mixtures thereof.
Polyols may be defined as compounds having at least two isocyanate reactive llydlug~ ~IA which may be employed in the preparation of polyurethane foams and elastomers. They are often prepared by the catalytic cnnrl_nR~;nn of an alkylene oxide or mixture of alkylene oxides either simultaneously or g.~~ ~n~;~lly with an orga~ic compound having at least two active hydrogen atoms, such as evidenced by U.S. Pat. Nos. l,922,459; 3,190,927; and 3,346,557. Representative polyols include polyhydroxyl-cnn~A;n;n~~J
polyesters, polyoYyalkylene polyether polyols such as the aful~ ' ;nn_rl polyoxyalkylene polyether polyols, polyhydroxy-terminated polyurethane polymers, polyllydlu~Lyl-~~nn~A;n;n~;
pho~phora~ rr~~ lkylene oxi~e adi~ct~ of polyhydric . , .
218q8ql 5 polythioesters, polyacetals, aliphatic polyols and thiols, ammonia, and amines ~nr1~l~1;ng aromatic, aliphatic, and heterocyclic amines, as well as mixtures thereof. Alkylene oxide adducts of ~ ~JUII~
which contain two or more different groups within the above-defined classes may also be used, for example, amino alcohols which contain lD an amino groups and a hydroxyl group. Also, alkylene oxide adducts of compounds which contain one SH group and one OH group as well as those which contain an amino groups and an SH group may be used.
Generally, the number average l e~ r weight of the polyols will vary from greater than 400 to 10, 000, and preferably from 2500 to 7, 000 .
Any suitable hydroxy-~Prm;n~tod polyester may be used such as are prepared, for example, from polycarboxylic acids and polyhydric alcohols. Any 8uitable polycdl~ylic acid may be used such as oxalic acid, malonic acid, succinic acid, glutaric acid, adipic 20 acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, brassylic acid, thapsic acid, maleic acid, fumaric acid, glutaconic acid, a-hydromuconic acid, B-IIYdL~ n; C acid, a-butyl-a-ethyl-glutaric acid, a, B-diethylsuccinic acid, isophthalic acid, terPrh~h;~l;,. acid, hemimellitic acid, and 1,4-Zs cycl~h~ An~d~c~r~oxylic ~cid. Any ~uit~le pol~ lric Qlcohol, " , ' 21898ql 5 ;n~ 9;ng both aliphatic and aromatic, may be used such aa ethylene glycol, propylene glycol, trimethylene ylycol, 1,2-h~tAnP~ , 1,3-bl~tiqnPr~ 1,4-butanediol, 1l2-ppntAnprl;nl, 1,4-pPntiqnp~ l, 1,5-pPntiqnPrl; ol, 1, 6-hP~iqnPrl; nl, 1, 7-heptanediol, glycerol, l, 1, 1-trimethylolpropane, 1, 1, 1-trimethylolethane, 1, 2, 6-hexanetriol, a-lO methyl glucoside, pentaerythritol, and sorbitol. Also included within the term "polyhydric alcohola" are ~ dç~ derived from phenol such as 2,2-bis(4-hydroxylphenyl)propane, commonly known as R; qphPn~-1 A. Preferred are diolg and triols for the manufacture of flexible polyurethane foams.
The hydroxyl-ct~nti~;n;n~ polyester may also be a polyester amide such as is obtained by ; n~ ; n~ some amine or amino alcohol in the reactants for the preparation of the polyesters. Thus, polyester amides may be obtained by rnn~lPn~; n~ an amino alcohol such as ethi~n-~l i nP with the poly~aLlJ~ ylic acids set forth above 20 or they may be made using the same components that make up the hydroxyl-cr~ntiq;n;n~ polyester with only a portion of the ~ llLs being a diamine such as ethylene diamine.
Any suitable polyoxyalkylene polyether polyol may be used such as the polymerization product of an alkylene oxide or a mixture of 25 alkylene oxides with a polyhydric alcohol. Any suitable polyhydric 218q8q~
alcohol may be used such as those disclosed above for use ln the preparation of the hydroxy-terminated polyesters. Any suitable alkylene oxide may be used such as those disclosed above for preparing the prepolymers. Polyethers which are preferred include the alkylene oxide addition products of trimethylolpropane, glycerine, propylene glycol, dipropylene glycol, and 2, 2 ' - (4, 4 ' -hydroxyphenyl) propane and blends thereof having efiuivalent weights of from 100 to 7, 000.
Suitable polyhydric polythioethers which may be condensed with alkylene oxides include the . ~ ; nn product of thiodiglycol or the reaction product of a dicarboxylic acid such as is disclosed above for the preparation of the hydroxyl-rf--~;n;n~ polyesters with any other suitable thioether glycol.
PO1YIIY~1LU~Y1--rfm~Aln;n~ phUh~UhUlUUh ~ L~f14 which may be used include those compounds disclosed in U. S . Pat . No . 3, 639, 542 .
Preferred polyllydlul~yl-cr~ntA;n;ng phosphorous compounds are prepared from alkylene oxides and acids of PIID~-UIIULUU8 having an acid equivalency of from about 72 percent to about 95 percent.
Suitable polyacetals which may be ~:u~d~lsed with alkylene oxides include the reaction product of ff)n~~l~Phyde or other 21898q 5 suitable aldehyde with a dihydric alcohol or an alkylene oxide such as those fl; Flrl ~78Pfl above .
Suitable aliphatic thiol8 which may be uulld~llse:l with alkylene oxides include alkanethiols rnntA;n;nrJ at least two -SH groups such as 1,2-ethanedithiol, 1,2-~Lu~c--le~ithiol, 1,3-propanedithiol, and 1,6-hexanedithiol; alkene thiola such as 2-butene-1,4-dithiol; and alkyne thiols such as 3-hexyne-1, 6-dithiol .
Suitable amines which may be uulldellse_ with alkylene oxides include aromatic amines such as aniline, o-chloroaniline, p-aminoaniline, 1,5-fl;i 'nr,nz~rhth:~lPnP, methylene fli~ P, the rr,nfl~n~At;rn product8 of aniline and formaldehyde, and 2,3-, 2,6-, 3,4-, 2,5-, and 2,4-diaminotoluene; ~l;rh~t;r amines such as methylamine, triisu~L"~ "l: nP, ethylPnPfl;: nP, 1,3-fl; ""l'LU~alle, 1,3-fl;: nnhlltzlnP, and 1,4-fl;: nnh~t~qnp~
Also, polyol8 rt~nt;l;n;n~ ester groups can be employed in the 20 subject invention. These polyols are prepared by the reaction of an alkylene oxide with an organic dicarboxylic acid anhydride and a compound rr~nt~;n;n'J reactive hydrogen atoms. A more comprehen3ive discussion o~ these polyols and their method of preparation can be found in U.S. ~?at. NOB. 3,585,185; 3,639,541 and 3,639,542.
" ~ 2189891 Polyols rrnt~;n;n~ graft polymer dlspersions may also be employed in the invention and are preferred. These are prepared by the in situ pol~. '7~tir,n~ in the polyols listed below, of an ethylenically unsaturated ~nomer or a mixture of ethylenically unsaturated monomers. Representative ethylenically unsaturated lC monomers which may be employed in the present invention include butadiene, isoprene, 1,4-r~n~ ;.onr, 1,6-h~ n~l;Pn~, 1,7-ort~ nf~, styrene, a-methylstyrene, 2-methylstyrene, 3-methylstyrene and 4-methylstyrene, 2,4-dimethylstyrene, ethylstyrene, isopropylstyrene, butylstyrene, phenylstyrene, cyclohexylstyrene, benzylstyrene, and 1~ the like; substitute styrenes such as cyanostyrene, niLL~I~LyL~lle, N,N-dimethylaminostyrene, acetoxystyrene, methyl 4-vinylbenzoate, phenoxystyrene, p-vinylphenyl oxide, and the like; the acrylic and substituted acrylic monomers such as acrylonitrile, acrylic acid, methacrylic acid, methyl acrylate, 2-hydroxyethyl acrylate, methyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, i80propyl methacrylate, octyl methacrylate, methacrylonitrile, ethyl a-ethoxyacrylate, methyl a-~r~t~m;nr,~rrylate, butyl acrylate, 2-ethylhexyl acrylate, phenyl acrylate, phenyl methacrylate, N,N-dimethylacrylamide, N,N-dibenzylacrylamide, N-butylacrylamide, :15 meth~crylyl ~on~mide, ~md the likej the vinyl e~ter~ yl 2 l 898~ ~
5 ethers, vinyl ketones, etc., such as vinyl acetate, vinyl butyrate, iGu~luu~ l acetate, vinyl formate, vinyl acrylate, vinyl methacrylate, vinyl methoxyacetate, vinyl benzoate, vinyltoluene, vinyl n5lphrh;l1 ene, vinyl methyl ether, vinyl ethyl ether, vinyl propyl etherg, vinyl butyl ethers, vinyl 2-ethylhexyl ether, vinyl 10 phenyl ether, vinyl 2 methoxyethyl ether, methoxybutadiene, vinyl 2-butoxyethyl ether, 3, 4-dihydro-1, 2-pyran, 2-butoxy-2 ~ -vinyloxy diethyl ether, vinyl methyl ketone, vinyl ethyl ketone, vinyl phosphonates such as vinyl phenyl ketone, vinyl ethyl sulfone, N-methyl-N-vinyl acetamide, N-vinyl-pyrrolidone, vinyl imidazole, 15 divinyl sulfoxide, divinyl sulfone, sodium vinylsulfonate, methyl vinyl F~l~l fnn~ , N-vinyl pyrrole, and the like; dimethyl fumarate, dimethyl maleate, maleic acid, crotonic acid, fumaric acid, itaconic acid, monomethyl itaconate, t-butyl 'nn~h methacrylate, dimehtylaminoethyl methacrylate, glycidyl acrylate, 20 allyl alcohol, glycol monoesters of itaconic acid, vinyl pyridine, and the like. Any of the known polymerizable monomers can be used and the ~ , J~ ds li8ted above are illustrative and not restrictive of the monomers suitable for use in this invention. Preferably, the monomer is selected from the group consisting of acrylonitrile, 25 ~tyrene and mixtures thereof.
The amount of ethylenically unsaturated monomer employed in the pol~ '7::1t;-1n reaction ig generally from 25 percent to 70 percent, pre~erably from 30 percent to 45 percent, based on the total weight of the product. The polymeri2ation occurs at a temperature between about 25~C. and 180~C., preferably from 80~C. to 135~C.
The unsaturated polyolb or macromers which may be employed in preparing the graf t polymer dispersion may be prepared by the reaction of any conventional polyol such as those described above with an organic compound having both ethylenic unsatura~:ion and a hydroxyl, carboxyl, anhydride, isocyanate or epoxy group or they may be prepared by employing an organic compound having both ethylenic unsaturation and a hydroxyl, carboxyl, anhydride, or epoxy group as a reactant in the pr~r~r~t~ nn of the conventional polyol. Re~LesellLative of ~uch organic ~ L~ include unsaturated mono- and polycarboxylic acids and anhydrides such as maleic acid and anhydride, fumaric acid, crotonic acid and anhydride, propenyl succinic anhydride, acrylic acid, acryloyl chloride, hydroxy ethyl acrylate or methacrylate and halogenated maleic acids and anhydrides, unsaturated polyhydric alcohols such as 2-butene-1,4-diol, glycerol allyl ether, trimethylolpropane .
5 allyl ether, pentaerythritol allyl ether, pentaerythritol vinyl ether, pentaerythritol diallyl ether, pentaerythritol vinyl ether, pentaerythritol diallyl ether, and 1-butene-3, 4-diol, unsaturated epoxides such as 1-vinyl-cyrlrlh~l~rnp-3~4-epoxide~ butadiene monoxide, vinyl glycidyl ether(1-vinyloxy-2,3-epoxy propane), 10 glycidyl methacrylate and 3-allyloxypropylene oxide (allyl glycidyl ether). If a polycarboxylic acid or anhydride is employed to incorporate lln~At~lrAt;nn into the polyols, it is preferable to react the llnRptllrAt~l polyol with an alkylene oxide, preferably ethylene or propylene oxide, to replace the carboxyl groups with 15 hydroxyl groups prior to employment in the present invention. The amount of alkylene oxide employed is such as to reduce the acid number of the unsaturated polyol to about 5 or less.
Illustrative polymerization initiators which may be employed are the well-known free radical types of vinyl polymerization 20 ;n;t;Atnrg guch ag the peroxides, persulfates, perborates, Pt:L~ t~ azo , ,~uu~ld~ etc. These include hydrogen peroxide, dibenzoyl peroxide, acetyl peroxide, benzoyl l~ydlu~u~lw~ide~ t-butyl llydLu~eluJLide~ di-t-butyl peroxide, lauroyl peroxide, butyryl peroxide, diisopropylbenzene h~ uu~lu~ide, ZS cumene h~uy~u~de, par~menth~ne hyd~ y~ de~ di.~cety1 , ; , .
2~89891 5 peroxide, di-a-cumyl peroxide, dipropyl peroxide, diisopropyl peroxide, isopropyl - t -butyl peroxide, butyl - t -butyl peroxide, difuroyl peroxide, bis (triphenylmethyl) peroxide, bis (p-methoxybenzoyl) peroxide, p-monomethoxybenzoyl peroxide, rubene peroxide, ascaridol, t-butyl ,uuLu~yb~ zoate, diethyl peroxyterPph~h;ll ~te, propyl hydLu~e~ u~ide, isopropyl hydluu~lu~Llde, n-butyl hydlu~u~:L,.~lde, t-butyl hydlu,u~:lu~lde, cyclohexyl hydLu,u~Lu~ide, trans-decalin IIYdL~I~UP~ 1PI a-methylbenzyl hydluL,~ Lide, a-methyl-a-ethyl benzyl lly~Lu~ueLu~idel tetralin hydLuuuLu~Lide~ triphenylmethyl hydLu~uelu~ide, diphenylmethyl llydlu~u~lu~ide, a,a'-azobis-(2-methyl heptonitrile), 1,1'-azo-bis (cyclohexane carbonitrile), 4, 4 ' -azobis (4--:y,lllu~uullLanoic acid), 2, 2 ' -azobis (isobutyronitrile), 1-t-butylazo-1-cyanocyn1 nhP~r;qnP, persuccinic acid, diisopropyl peroxy dicarbonate, 2,2'-azobis(2,4-dimethylvaleronitrile~, 2-t-butylazo-2-cyano-4-methoxy-4-methylpentanel2l2l-azobis-2-methylh~l~Anpnitrile~ 2-t-butylazo-2-cy~nnh~lt~np, 1-t-amylazo-1-cyanocyclohexane, 2,2'-azobis(2,4-dimethyl-4-methoxyvaleronitrile, 2, 2 ' -azobis-2-methylbutyronitrile, 2-t-butylazo-2-cyano-4-methylpentane, 2-t-butylazo-2-i~locutyr~nitrile, to butylpero y _ropyl ~Arhr~n~t~ an~ the likej a mixture of initiators may also be used. The preferred initiators are 2, 2 ' -azobis (2-methylbutyronitrile~, 2, 2 ' -azobis (isobutyronitrile), 2, 2 ' -azobis (2, 4-dimethylvaleronitrile), 2-t-butylazo-2-cyano-4-methoxy-4-methylpentane, 2-t-butylazo-2-cyano-4-methylpentane, 2-t-butylazo-2-cyano-butane and lauroyl peroxide. Generally, from about 0.1 percent to about 10 percent, preferably from about 1 percent to about 4 percent, by weight of initiator based on the weight of the monomer will be employed in the process of the invention.
A particularly preferred polyol for use in the instant invention will be a graft polyol having from 5 to 60 percent vinyl, the monomer being comprised of a mixture of acrylonitrile and styrene, in a carrier polyol having a number average i l~clllAr weight of from 2000 to 10, 000. The carrier polyol will preferably have a tr; f-lnr~ n~l initiator and contain at least 5 percent ethylene oxide, most preferably a 5 to 60 96 E0. However, it will be appreciated that while not preferred, the use of carrier polyols having no E0 is within the scope of the invention.
A most preferred graft polyol will have from 10 to 50 ~6 of a mixture of acrylonLtrile and styrene in a carrier polyol having an initiator selected from the group consisting of trimethylolpropane . , , 2~89~91 5 and glycerine, arld a ilumber average, ~ Flr weig~lt; o~ ~on~ 300 to 7000. ~'he ~arrier polyc~l wi}l pre~era~1y contain L0 I;o 30 % ~30.
A~ ;n~ I Pr1 above, tlle polyol componellt will ~18~1ally al~o contain a uret~lane promotin~ cata.ly3l alld e~ blowillg ay~ t.
~ ny sui~:.able urQ~arle prom~ lg cal;aly3t may be u~~e~ rJ ~
10 tertiary alnine~ h ~, for exall~ple, triethyl,anPAii 'Tl~, N-methylmvLp~lolille, N-~t~lylm~rp~lolille, ~ie~.ilyleth ~nl; n~
C ~IIJ1irle~ eth~1 4_dime~h~ rI~Pr~Y1PiPerZ~Zine~ 3-metl~ y~ yldi~ t~lylanlinel ~,N,~'-trimetl~yli~opropyl propylPn-"l;. n~, 3-diet}-ylami!lopropyldieti~yla~nine, 15 dimethylbe~zyla~nirle, ~md ~lle like~ ~ther sui~able cataly~.ts are, i~o~ e~can~ple, 3tal~rl0u3 ch~oride, dibutylt~l di-2-e~lyl }IP~Tl~te~
~italmous vxide, a~s well ~s ot}le.r ~L' . . t~ compoundE ~uch ~s are disalosed in U.S. Pa~. ~o. 2,8~6,40~.
8ui~able blowing aye~lts illclude water, chen~i~ally inert, low ~0 boili~lg, ~Iy~ro~arbons and halogenated ~ d-v~a-l~OIIs alld mixtures t~lereof. E:xampLes o~ the la~er i.nclude t~lo~,e having boil.illy points below 50 degrees C and pIe~erably bet:ween -50 C aIId 30 C at atmospheric pressure.
Illu3trative e~ les Or ~iuitable blo~irly ayentb are haloyena~ed 35 h~ Oh v~3 n~ ~cl-lolodl~
.. . .
dichlo~ nromethane, dichlorofluoromethane, and trichlorofluoromethane and their mixtures, and h~dLuuaLbull5 such as propane, n-butane, and isobutane a~ well as dimethyl ether and cyclopentane, acetone and formic acid.
However, in general, water is the most preferred blowing agent 10 for use with the instant invention.
In any case, it is neces8ary that the blowing agent be present in an amount sufficient to be r~rnn~;hl~, at a minimum, for at least 95 percent of the expansion of the polyurethane foam.
However, it is preferred that the blowing agent be responsible for 15 essentially all or at least 98 percent of the expansion of the foam. Most preferably, the blowing agent will be responsible for 100 percent of the PYpAIl~; nn of the foam.
In any event, no expansion of the foam 8hould be the result of the inert gas injected into the ,~ streams. Those skilled 20 in the art will appreciate that the required quantities of blowing agent can be determined experimentally as a function of the desired density and amount of the foam, A3 ;n~i;r2~-~fl aoove, optional elements or additives of the polyol . .~ stream can include surfactants, chain ~ n~nrl~rp~, 25 flame-inhibitors, An~;n~ n~, lnorganic and organic acids, . ~
5organic f illers, pigment3 and colorants, antistatic additives and mixtures thereof.
Chain-~t~nrl;n~ agents which may be employed in the preparation of the polyurethane foams include those ~ ds having at least two fllnr~;nn~l groups bearing active hydrogen atoms such aa water, hydrazine, primary and secondary diamines, amino alcohols, amino acids, hydroxy acids, glycols, or mixtures thereof.
Such agents will generally have a number average I 1 Pr~ r weight of less than about 400. A preferred group of chain-l~ on~l;n~
agents includes water, ethylene glycol, 1,4-b~tt~n~-~;nl and primary and secondary diamines which react more readily with the prepolymer than does water 6uch as phenylene diamine, 1,4-cyclohexane-bis-(methylamine), ethylf~n-~A;, nr, diethylenetriamine, N- (2-hydroxypropyl ~ ethyl F~n.,~1;; nP, N, N ' -di ( 2 -hydroxypropyl)ethylon~; nP, piperazine, and 2-methylpiperazine.
A surface-active agent is generally necessary for production of high yrade polyurethane foam according to the present invention, since i~t the absence of same, the foams generally collapse or contain very large uneven cells. Numerous surface-active agents have been found satisfactory. Nonionic surface-active agents are preferred. Of these, the nonionic surface-active agents such as 5 the well-known silicones have been found particularly desirable.
Other surface-active agents which are operative, although not preferred, include paraffin oils, castor oil, turkey red oil, polyethylene glycol ethers of long chain alcohols, tertiary amine or ;~lk~nnl: 'nP salts of long chain alkyl acid sulfate esters, 10 alkyl sulfonic e~ters, and alkyl arylsulfonic acids.
Among the flame retardants which may be employed are pental,L~ '; rhPnyl oxide, dibL~ , u~allul, tris ( 5-chloropropyl)pho8phate, 2, 2-bis (bromoethyl) 1, 3-propanediol, tetrakis(2-chloroethyl)ethylene fl~rhr~rhA~P, tris(2,3-15 di~L~ , u~yl)phosphate, tri~(:3-chloroethyl)rhr~ph~pl tris(l,2-dichloropropyl)rhr~rh~e, bis- (2-chloroethyl) 2-chloroethylpllo~ ul.ate, molybdenum trioxide, . ~ molybdate, ammonium phosphate, pentabL~ lrhPnyloxide~ tricresyl phosphate, hexabromocyclododecane, melamine, and dibromoethyl-20 dibromocyrl~h~ np~ The concentrations of flame retardant compounds which rnay be employed range from 1 to 100 parts per 100 parts of polyol mixture.
The isocyanate and polyol r~-nt~;ninrJ component streams will generally be introduced into polyurethane foam making machine such 25 as are well known to those skilled in the art. Machines -5 particularly suited to the production of ~lexible polyurethane slabstock foam are particularly preferred. Illustrative examples are the M-30 Lab Machine and the ~ennecke U~sT-63. Through machines are well-known in the art and are described, for example, in IJ.S.
Patent 4, 074, 960 and 4, 298, 557 .
The inert gas to be injected into the isocyanate and polyol ~-nn~;l;n;n~ streams will generally be of a type which will not react with the polyurethane ~ ~J i,.." .,l R, such as inert gases or noble gases. Illustrative examples include air, carbon dioxide, nitrogen, or argon. Preferred gases are carbon dioxide and nitrogen. Carbon dioxide is most preferred.
The amount of inert gas to be injected will be incapable of producing any measurable ~ nc;~-n of the flexible polyurethane slabstock foam. That is, the amount injected should be capable of producing only negligible ~ nR;~-,n of the foam, if any.
The inert gas may be injected into one or both of the gtreams. In general, the gas will be injected into that -n~ stream which exhibits the greatest solubility for a particular gas. The gas may also be injected into the combined streams of ~ , R, ~ In general, the amount of inert gas to be in; ected will be 0.0010-l.o weight percentage of the selected ~, ' stream.
In~ection into isocyanate stream is most pre~erred. E~or example, it is preferred to have inert gas injected at 0 . 0050-0 . 750 weight percent of the isocyanate ~ L~ t stream. Most preferably, inert gas will be injected at an amount of 0.010-0.50 weight percentage of the isocyanate. The isocyanate amount will be based upon 100 parts by weight of the polyol - ~ stream.
The location of inj ection will vary depending on a variety of factors 8uch ag machine type, metering and mixing Pr~ ', polyol 15 selection and isocyanate selection. In general, the gas will be injected into the selected stream at a location facilitated by the machine design. Examples of suitable in~ection locations include the ~, manifold on a pour head, the suction side of a high shear or h~ " 7; n~ pump inline with the polyol stream, and the 20 suction side of a high pressure polyol and/or i~ocyanate pump.
In general, the inert gas is inj ected with the aid of a hypodermic needle, such as an 18 gauge No. 2 point type.
The solubility of the inert gas in the selected stream or streams may be effected by a variety of factors.
"' .
5 Generally, it is desirable to increase the ~nl~lh;lity of the inert gas in the selected ~ _ stream(s).
It has been found that factors such as _ stream ILes~uLès and ~ _ t ~ 8, inert gas pressure and t _ dLul~, head pressure and mixer speed may play a role in the effectiveness 10 of the injected inert gas and thus on the final rh~r~rt~r; ~tics of the r~ lt;n~ foam. (~ _ and gas ~L~suLt~8 and ~, cLLuL~:s will generally depend on the identity of the particular or gas used, as well ag the type of foam production Pq~l;
; 1 i 7~
Similarly, the ~ c~inn of an optimum head pres8ure and mixer speed will also depend on the same factors. However, as ~' LLaLed in the following working examples, it may be stated that head pressure should be ~-;n~;nP~l at a range of between 5 to 30 psig. TnrrPA~; ng the mixer speed was also found to have a 20 rlP~;r~h~P effect on the final foam obtained. Those skilled in the art, however, will appreciate that head pressure and amount of mixed speed are related.
Tho8e skilled in the art will appreciate that ultimately, either before or after the injection of the inert gas, the 25 isocyanate and polyol rnn~;~in;n~, ' stream8 will be brought together 80 as to facilitate a reaction tht:L~ L-~ccn. The length of reaction time will depend on the selection of the particular llLs selected and the foam production e~ utilized.
However, illustrative free rise reaction times with respect to typical slabstock tl;cp~nc;n~ eguipment are 12 to 20 seconds for 10 cream time and approximately 1 to 3 minutes for rise time.
Flexible polyurethane slabstock foams produced ~-rnr~1ing to the invention exhibit an optimum, ' n~t;nn of feel, comfort and wear characteristics It is believed that these attributes will be possessed by foamg having (a.) a particular cell gize dig~r;h~1t-nn, 15 (b. ) a particular catastrophic fatigue value, and (c . ) a particular visual appearance.
While not wishing to be bound to a particular theory, it is believed that cell size dis~r;hu~;nn i8 particularly relevant to the achievement of optimum comfort and wear characteristics in 20 flexible polyurethane slabstock foams.
Cell size distribution is intended to refer to both the size of the cells and the number of each size of cell present i~ a cro8s section of the foam. Terms such as fine and coarse L~L~8c!llL t~e ends of a spectrum which generally relates to the size of the 25 cells, while random and uniform often refer to the end points of a ' ~
5 spectrum referring to the number of certain sized cells present in a cross section of the foam. Those skilled ln the art will appreciate, however, that with respect to cell ~ize, the particular numbers may be somewhat d~t!lld~ lL upon foam type and composition.
In general, fine cells are preferred over coarse cell8 when 10 optimi7~;nn of p~Lr~ e properties such as fatigue, tensile strength, tear strength, elongation and support factor are desired.
With respect to the most preferred foams of the invention, fine cells may be defined as those having a maximum diameter of 1.0 mm, while coarse cells can loosely be termed as those having a 15 diameter greater than the maximum diameter for fine cells.
Random cell structures will be those wherein no one cell size range (ie., cells having a diameter which is within ~ or - 10096 of the average cell diameter) constitutes a majority of all visible cells in a cross section of the foam. Uniform cell structures 20 will be those wherein a majority of the visible cells are within a particular cell size range. It ig currently believed that optimum wear characteristics are obtained with random structures.
E~owever, while foam6 which may be characterized as both fine and random are believed to be preferred, it is possible that a foam .~
5 capable of only one such ~hArA~tPr;7~tirn may exhibit the superior properties of the claimed polyurethane cl ~hctn~-k foam.
DPc~;rAhlp foam8 will generally be those having a cell bLLucLuld such that at least 1096 and preferably 2096, of the cells visible in a crogs gection of the foam are within a common cell 10 size range. Preferably, said 10% of cells will have a diameter of at least 0.1 mm.
More particularly, with re8pect to the most preferred foam of the invention, it is believed that in general, at least 90 percent of the cells present in a cros8 section of the foam 8hould have a diameter between 0.1 and 1.0 mm. Preferably at least 75 percent of the cells will have a diameter between 0 . 2 and 0 . 8 mm. Most preferably, at least 40 percent of the cell8 will have a diameter between 0.3 and 0.6 mm.
~ Ptprm;nAt;r~n of cell size distr;hl~t;~n may be done either 20 manually with a 8tereo microscope and a grid or inbLl ' ~lly using a " ' Pr; 7PCI video imaging and ~lltl ~ Prl cell counting system. Cell cize counts may be given as cells per- inch ~cpi) or as a r ~ of cell size diameter in m;ll; Prc.
Optimum wear ~h~r~rtPr;ct;r~c are exemplified by certain 25 rs~t;~ctrt~rh; c fatigue values . A8 used herein, catastrophic fatigue ~ 2 1 8~89 1 5 is defined by two testing parameter6, both resulting from ASTM test D3574(40k cycles, no carpet). First, the percent 1088 in height is measured~ It should be no more than 10~~, with less than 5~ lost being preferred, and less than 296 lost being most preferred.
Second, the 9~ hardness retained at 65'6 IFD ~f~pct;~n should be at least 509f, with at lea6t 609~ being preferred and at least 65~6 being most preferred.
Finally, the performance and comfort characteristic are also ;n~ PnrPcl by the vigual appearance of the foam. That is, the foam should be 8ubstantially free of large voids, which may be 15 classified by the size of their diameter8. As indicated previously, voids having diameters of from lmm to 3mm are defined a~ buckshot, while voids having diameters of from 3mm to 6mm are peahole8. It is desirable that the foam be substantially free of peaholes. By "substantially free" it is meant that the foam have 20 no more than 1 to 2 peaholes per square meter.
The invention is further illustrated, but is not intended to be limited by the following examples in which all parts and percentages are by weight unless other~qise specif ied .
E~l~
ZS he iollowing :~ ~rial~ wer; u~ed in the ewanple~ below:
,~ , Polyol A is a graft polyol commercially available from BASF
Corporation of ~yandotte, Michigan, PLURACOL~ Polyol 1231 D; ~th;lnnl; n~ LF is a produce of VAN WATER & ROGERS Inc.
DC-5164 Silicone surfactant iB a product of AIR PRODUCTS
DABCOr 33LV Catalyst is a product of AIR PRODUCTS
DABCo'9 T-12 Catalyst i8 a product of AIR PRODUCTS
ANTIBLAZl~l 100 is a product of ALBRIG~IT ~ WILSON
Iaocyanate B is a mixed isocyanate commercially available as LUBR~NATE~ No. 236 ISO from BASF Corporation.
All urethane ~ ,~ulle~lLs were metered in separate streams into a pin-mixer type low pressure pour-head which then dispensed the reacting mixture onto a moving conveyor. The dispensed li~uid mixture at a prescribed time began to cream then expand, shaped by the moving conveyor and static side wall8. This rnnt;n~lml~
reacting foaming operation was allowed to run until a 15-foot block of foam was made. The foam block was allowed to cure for minimum 72 hours at ambient r~n~l;t;nn~ after which standard test pads were cut for physical ~!L~ L~y testing.
Foam blocks were prepared with Polyol A and Isocyanate B at 110 index using a 2.1 pbw water f l;~t;nn and related ancillary , ~ are listed in Table 1:
.
E~T.~TTnN, ~bw = 1 2 Polyol A 100 . 0 100 . 0 100 . 0 Water Added 2.1 2.1 2.1 ni~th;~n~ ' n~ LF ~ ~ 7 ~ ~ 7 ~ ~ 7 DC-5164 Surfactant 1.5 1.5 1.5 DA}3COl 33LV 0.15 0.15 0.15 DA13CO~ T-12 0.1 0.1 0.1 ANTIBLAZE~ 100 3 . 0 3 . 0 3 . 0 Isocyanate B (110 40.5 ~ 40.5 40.5 Index) ~~q.~ rr'_TT.TnN.C~ -Injection Point Isocyanate-----~ -------->
Nucleating Gas Type N2 CO2 CO2 Gas Flow Rate, L/min . 3 . 4 3 . 2 4 . 0 Gas Temperature, ~F 71 71 71 Gas Pressure, psig 10 10 20 Wt . of gas in iso 0 . 05 0 . 07 0 .12 stream, ~
Pour Head Pres., psig 10 10 7 Iso Inject. Pres., 400 500 500 psig F~" P~u~
Density, PCF 3 .1 2 . 9 3 .1 IFD, lbs 91 129 116 Support Factor 2.45 2.07 2.48 Air Flow, CFM 0.4 0.2 0.4 Cata~trophic ~atigue 40k cycles no carpet Height, 96 loss 1.3 8.4 1.8 6596 IFD96 hard . 81. 5 38 . 5 80 . 7 Retained 2 ~ 8989 1 Visual D~R rri rt i nn Cell Size Random Uniform Random Pore ~rr~ArAnr~ TrrPrJlll Ar .Crhl~r; r il Trr~rJlll Ar Average Cell Diameter, 0.42 0.~6 0.45 mm Cell Diameter Range, 0.14-0.75 0.30-0.60 0.18-0.95 mm Cell Count Per Inch 75-70 63-58 73-68 ~Cell - ~ made with RAM Optic ArrArAtllC
Comparing f~ lAt;nn 1 with 3 ;n~l;rAtF~l that foams J~l~rloAt~
with either N2 or COI gave a similar cell pattern and fatigue lO properties. The fatigue rPrfnrr~nr~ of fl lAt;nn 3 was improved over f~ lAt;nn 2 due to ;nrr~Acer3 . .".rr~ ..1 ;nn of C0~ in the isocyanate stream and lower pour-head pressure. The foam produced with fl lAt;nn 3 with CO2 n~lrl~At;nr; gas had ~;gTl;f;r;mtly reduced number of defects in comparison with the one produced with fl 1i3t;nn 1 uging N, gaa. Phntn~rArhç: of these foams at 23x --~n;f;r?t;nn are attached aa Figurea 1, 2, and 3. Figure 1 illllS~trAtf~q foam 1 with defectg, Figure 2 illustrates foam 2 without defects and Fi ,ure 3 ;llllCtrAt~c foam 3 without defects.
It should be u-ld~ Dl,o~J'i that while the invention as shown and 20 described herein ;lll~~trAtPq currently prF~frrr~ - c of the invention, it is not intended to illustrate all possible forma thereof.
218~891 , 5 A variety of polyull:LIIalle foams can be created by one of ordinary skill in the art without departing from the spirit and scope of the invention disclosed and claimed.
Claims (12)
1. A flexible polyurethane slabstock foam having superior feel, comfort, and wear characteristics the foam resulting from a process of making comprising:
providing a stream of an isocyanate containing component providing a stream of a polyol containing component having a blowing agent which is responsible for at least 95 percent of the expansion of the foam;
injecting an amount of an inert gas into one or more of the isocyanate or polyol containing component streams, the amount injected being capable of producing only negligible expansion of the foam; and reacting the steams together for a time sufficient to produce a polyurethane foam;
the resulting polyurethane slabstock foam being characterized by:
(a.) a cell size distribution wherein at least 20 percent of the cells visible in a cross section of the foam have a diameter of at least 0.1mm; and (b.) a substantial absence of cells having a diameter which is at least four times greater than the common cell size.
providing a stream of an isocyanate containing component providing a stream of a polyol containing component having a blowing agent which is responsible for at least 95 percent of the expansion of the foam;
injecting an amount of an inert gas into one or more of the isocyanate or polyol containing component streams, the amount injected being capable of producing only negligible expansion of the foam; and reacting the steams together for a time sufficient to produce a polyurethane foam;
the resulting polyurethane slabstock foam being characterized by:
(a.) a cell size distribution wherein at least 20 percent of the cells visible in a cross section of the foam have a diameter of at least 0.1mm; and (b.) a substantial absence of cells having a diameter which is at least four times greater than the common cell size.
2. The flexible polyurethane slabstock foam of claim 1, resulting from the process of making wherin providing an isocyanate stream comprises providing an isocyanate component comprising:
(i)diphenylmethane diisocyanate isomers;
(ii)modified isocyanates containing uretoneimine-carbodiimide, allophanate, and/or isocyanaurate structures;
and (iii) toluene diisocyanate.
(i)diphenylmethane diisocyanate isomers;
(ii)modified isocyanates containing uretoneimine-carbodiimide, allophanate, and/or isocyanaurate structures;
and (iii) toluene diisocyanate.
3. The flexible polyurethane slabstock foam of claim 2, resulting from the process of making wherin providing an isocyanate stream further comprises providing an isocyanate component consisting essentially of (i) 20 to 95 weight percent 4, 4-diphenylmethane diisocyanate;
(ii) 1 to 60 weight percent modified isocyanate containing uretoneimine-carbodiimide, allophanate, and/or isocyanaurate structures; and (iii) 1 to 60 weight percent toluene diisocyanate.
(ii) 1 to 60 weight percent modified isocyanate containing uretoneimine-carbodiimide, allophanate, and/or isocyanaurate structures; and (iii) 1 to 60 weight percent toluene diisocyanate.
4. The flexible polyurethane slabstock foam of claim 1, resulting from the process of making wherin providing providing a polyol containing stream further comprises providing a blend of:
(i)a polyol comprising a graft polyol;
(ii) a urethane promoting catalyst;
(iii) a blowing agent responsible for 100 percent of the expansion of the foam which comprises carbon dioxide generated in situ; and (iv) one or more additives selected from the group consisting of surfactants, chain extenders, flame inhibitors, anitoxidants, and mixtures thereof.
(i)a polyol comprising a graft polyol;
(ii) a urethane promoting catalyst;
(iii) a blowing agent responsible for 100 percent of the expansion of the foam which comprises carbon dioxide generated in situ; and (iv) one or more additives selected from the group consisting of surfactants, chain extenders, flame inhibitors, anitoxidants, and mixtures thereof.
5. The flexible polyurethane slabstock foam of claim 4, resulting from the process of making wherin providing providing a polyol containing stream further comprises providing a blend containing:
(i)a graft polyol having from 5 to 60 percent vinyl monomer selected from the group consisting of acrylonitrile, styrene, and mixtures thereof, the vinyl monomer being in a carrier polyol having a number average molecular weight of 2000 to 1000.
(i)a graft polyol having from 5 to 60 percent vinyl monomer selected from the group consisting of acrylonitrile, styrene, and mixtures thereof, the vinyl monomer being in a carrier polyol having a number average molecular weight of 2000 to 1000.
6. The flexible polyurethane slabstock foam of claim 1, resulting from the process of making wherin the step of injecting further comprises injecting from 0.0010 to 1.0 weight percent of an inert gas into the selected component stream.
7. The flexible polyurethane slabstock foam of claim 1, resulting from the process of making wherein the step of injecting further comprises injecting carbon dioxide into the isocyanate stream.
8. The flexible polyurethane slabstock foam of claim 7, resulting from the process of making wherein the step of injecting further comprises injecting 0.0050 to 0.750 weight percent carbon dioxide into the isocyanate stream, as based on the total weight of the isocyanate stream.
9. The flexible polyurethane slabstock foam of claim 1 further characterized by a cell size distribution wherein at least 90 percent of the cells visible in a cross section of the foam have a diameter between 0.1mm and 1.0mm.
10. The flexible polyurethane slabstock foam of claim 1 further characterized by a substantial absence of cells having a diameter which is at least three times greater than the common cell size diameter.
11. The flexible polyurethane slabstock foam of claim 1 further characterized by (c.) a catastrophic fatigue value characterized by (1.) a percent loss in height of no more than 10%, and (2.) a percent hardness retained (65% IFD deflection of no less than 50%.
12. The flexible polyurethane slabstock foam of claim 11 wherein the foam is further characterized by a catastrophic fatigue value characterized by (1.) a percent loss in height of less than 5%, and (2.) a percent hardness retained (65% IFD deflection of at least 60%.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US55727095A | 1995-11-14 | 1995-11-14 | |
| US08/557,270 | 1995-11-14 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2189891A1 true CA2189891A1 (en) | 1997-05-15 |
Family
ID=24224731
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2189891 Abandoned CA2189891A1 (en) | 1995-11-14 | 1996-11-07 | Flexible polyurethane slab stock foam having superior feel, comfort and wear characteristics |
Country Status (2)
| Country | Link |
|---|---|
| CA (1) | CA2189891A1 (en) |
| MX (1) | MX9605362A (en) |
-
1996
- 1996-11-05 MX MX9605362A patent/MX9605362A/en unknown
- 1996-11-07 CA CA 2189891 patent/CA2189891A1/en not_active Abandoned
Also Published As
| Publication number | Publication date |
|---|---|
| MX9605362A (en) | 1997-05-31 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CA2154836C (en) | Polyisocyanate compositions for the preparation of flexible polyurethane foams | |
| US4381352A (en) | Process for reinforced reaction injection molding of polyurethanes | |
| CA1319208C (en) | Storage stable polyisocyanates characterized by allophanate linkages | |
| US5594037A (en) | Polyurethane SRIM compositions having internal mold release properties | |
| KR970006671B1 (en) | Moldable energy absorbing rigid polyurethan foam and method of making the same | |
| EP1252215B1 (en) | Process for preparing a free rise or slabstock flexible polyurethane foam | |
| CA2094554C (en) | Polymethylene polyphenyl polyisocyanate based prepolymers | |
| US4994502A (en) | Process for the preparation of integral skin polyurethane steering wheels | |
| GB2331102A (en) | Energy absorbing water blown rigid polyurethane foam | |
| US5686187A (en) | Molded polyurethane SRIM articles | |
| US6262139B1 (en) | Polyisocyanate compositions for the preparation of flexible polyurethane foams | |
| US4738993A (en) | Rim microcellular polyurethane elastomer employing heteric or internal block ethylene oxide polyols | |
| US4314038A (en) | Graft polyol RIM system possessing excellent thermal properties | |
| MXPA96004853A (en) | Polyurethane articles, molded by the reacc structural injection molding process | |
| CA2232350C (en) | Polymeric mdi prepolymer compositions and flexible foams prepared therefrom | |
| US5216041A (en) | Energy absorbing, water blown, rigid polyurethane foam | |
| US5700390A (en) | Polyol compositions having internal mold release properties | |
| US4550153A (en) | Elastomer based on crude diphenylmethane diisocyanate and aniline in the RIM process | |
| CA2190174A1 (en) | Polyurethane compositions having internal mold release properties | |
| US5716439A (en) | Internal mold release compositions | |
| CA2189891A1 (en) | Flexible polyurethane slab stock foam having superior feel, comfort and wear characteristics | |
| MXPA96004868A (en) | Compositions of poliol, which have internal properties of liberation of the mo | |
| US5686526A (en) | Process of making molded polyurethane articles | |
| EP0774485A2 (en) | Process of making a flexible polyurethane slab stock foam having superior feel, comfort, and wear characteristics | |
| MXPA96004871A (en) | Internal compositions of liberation of the mo |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Dead |
Effective date: 20021107 |