amounts of hydroxymethylated resin acid derivatives in addition to VIa were suggested, by the minor peaks which appeared in glpc chromatograms. Effective separation of the hydroxymethyl-substituted resin acid by commercial continuous countercurrent extractors is suggested as a way to increase the utility of these materials. literature Cited
Bain, J. P. (to Nelio Resin Processing Co.), U. S. Patent 2,374,657 (May 1945). Black, D. K., Hedrick, G. W., J . Org. Chem., 32, 3763 (1967). Bried, E. A. (to Hercules Powder Co.), U. S. Patent 2,383,289 (Aug 1945). Hedrick, G. W., Ind. Eng. Chem., Prod. Res. Develop., 12, 246
Levering, D. R. (to Hercules Powder Co.), U. S. Patent 2,906,745 (Sept 1959). Levering, D. R., Glasebrook, A. L., Znd. Eng. Chem., 50, 317 (1958)
Lewis, J. B., Hedrick, G. W., Znd. Eng. Chem., Prod. Res. Develop., 9, 304 (1970).
Parkin, B. A., Jr., Hedrick, G. W., J. Org. Chem., 30, 2356 (1965). Parkin, B. A., Jr., Summers, H. B., Jr., Settine, R. L., Hedrick, G. W., Ind. Eng. Chem., Prod. Res. Develop., 5, 257 (1966). Rohde, W. A,, Hedrick, G. W., unpublished work, 1968. Rohde, W. A., Hedrick, G. W . , - I n d . Eng. Chem., Prod. Res. Develop., 10, 447 (1971).
Rovals, E. E.. Greene. J. L.. Jr.. J . Ora. Chem.. 23. 1437 (19581. ~, Sugathan, K.'K., Rohde, W: A.,' Hedrrck, G. W., i.Chem. Eng. Data, 16, 161 (1971).
(1973). Joye, N. M., Jr., Lawrence, R. V., J . Chem. Eng. Data, 12, 279 (1967).
RECEIVED for review April 16, 1973 ACCEPTEDJune 11, 1973
AI koxylated Hydroxymethylated Rosin Derivatives as Reactants for Rigid Polyurethane Foams Glen W. Hedrick" Naval Stores Laboratory, Southern Region-FloridalAntilles
Area, A R S , USDA, Olustee, Fla. 32072
The alkoxylation of resin acids modified b y the addition of methylol groups with alkylene oxides i s described. These modifications were obtained (a) b y oxonation, via isomerization, of the levopimaric-formaldehyde adduct to 1 2-hydroxymethylabietic acid and its hydrogenation including conversion of the carboxyl to methylol group and (b) b y reaction of rosin with formaldehyde in acetic acid and low-pressure catalytic hydrogenation. In the latter reaction sequence, liquid-liquid extractions using an aqueous methanol-hexane solvent system were effective in separating methylolated resinyl materials from unreacted materials. A number of rosin modifications with foam formulations containing up to 55% of the resinyl glycols have been utilized to prepare rigid polyurethane foams. These chemicals are compatible and processable in urethane foam formulations. Acceptable foam properties were obtained when compared with foams from commercial glycols.
Investigations in this laboratory to increase the functionality of rosin and resin acids have been concerned with the addition of hydroxymethyl groups to rosin per se and abietic and levopimaric acids as summarized in the previous article (Rohde, et al., 1973). The present paper is principally concerned with the alkoxylation of some of these materials and incorporation of the glycol derivatives into rigid polyurethane foams. No one has investigated the use of hydroxymethylated resin acid derived glycols in rigid polyurethane foams. However, Gemeinhardt, et al. (1962), and Hudson (1963) described the use of crude tall oil (approximately 50% rosin) in foams of this type. Szabot (1966) alkoxylated a rosin monoglyceride and used i t in foams. Darr and Backus (1967) and Delmonte (1967) described the use of a n alkoxylated stump wood extract commonly known as Vinsol. Xlkoxylated Vinsol, Hercules Poly01 EOV, has been available for some years. Ethoxylation of the Diels-Alder adduct of fumaric acid and rosin has been described by Class (1970). The use of the ester
* To whom correspondence should be addressed at 2921 Inglewood Ave., Lake City, Fla. 32055. 246 Ind. Eng. Chem. Prod.
Res. Develop., Vol. 12, No. 3, 1973
in polyurethane foams was suggested. The compositions of Vinsol and ethoxylated Vinsol (Rummelsburg, 1951) and their uses in polyurethane foams were described in Hercules' Bulletin PC-187 (1967) and by Darr and Backus (1967). According to the supplier, Vinsol contains 57% polynuclear polyhydric phenolics, 28y0 resin acids and derivatives, and 15% neutrals (nonacidic materials) : neut equiv 587, sap equiv 318, OH equiv 309 (1.9 OH groups/equiv of acid). The ethylene oxide adduct of the acid, Hercules Poly01 EOV, has a n OH equiv of 218 which corresponds to 1-mol addition of the oxide to Vinsol. Of the resinyl derivatives considered in this report hydroxymethylated rosin, its methanol extract, and oxonated rosin resemble Vinsol most in chemical structure. I n addition to these, the hydroxy acid and glycols I and I1 respectively complete the list of hydroxylated resinyl materials used in this study. I n practice, products represented by I, 111, and VI were hydroxymethyl-substituted dihydro resin acids differing only in the position of the double bond. The alkoxylation of materials such as those above has not been reported, except for the following. The propylene glycol
~~
CH,OH
w CH,OH
I
I1
E)"
@
CH,O(RO),H
IIIa, OH equiv 2 2 7 . 8 IVa, R = ethylene b, OH e q u i v 203.5 b, R = isopropylene x , somewhat more than 1 x , somewhat more than 1
@
(CH@H).,
CO,R Va, R = oxonated rosin R = dipropylene glycol ester b, R = CH, c,R=H x = -l.O/mol; '/, di- and 2/3 monomethylol in reacted portion
@CH20H); CO,R VIa, R = H b, R = (C,H,O),H x = -1 y = a n average of approximately l.O/mol; 2 / 3 di- and monomethylol
in reacted portion VIc, glycol ester of methanol extract of VIa ester of the hydroxy acid I was prepared by allowing propylene oxide to react with the acid dissolved in dimethylformamide (DAIF) (Lewis and Hedrick, 1970), in accordance with Kolbe (1959). Rummelsburg (1951) made the monoethylene glycol ester of Vinsol by continuous addition of ethylene ovide to Vinsol under pressure using an alkaline catalyst. Since pumping facilities were not available to add the oxide continuously, all alkoxylations mere made in D M F . Alkoxylated resinyl materials were mixed with PeP 450, surfactant, catalysts, and blowing agent for reaction with a polymeric isocyanate in a one-step foaming procedure, and also with a quasiprepolymer made from PeP 450 and a polymeric isocyanate in a two-step procedure. The resinyl products comprised 55% by weight of the glycol mixture in the formulations for the one-step process and SOY0 by weight in the two-step method. In the foam studies. resinyl glycols were compared with commercial glycols (Table I) having functionalities from 2 to 8. The latter glycol, a sucrose derivative with 8 possible free hydroxyl groups, had a functionality of only 6+ according to the manufacturer (Hedrick, 1970).
~~
Table 1. Materials Used for Foams. Isocyanates Mondur MT 40, a polymeric isocyanate, equiv wt 115, Mobay Chemical Co., Pittsburgh, Pa. lfondur M R and MRS,polymeric isocyanates, equir wt 132, Mobay Chemical Co., Pittsburgh, Pa. Glycols Voranol RS 450, OH equiv 129.6, sucrose polypropylene glycol polyether, functionality 6 + , Dow Chemical Co., Midland, llich. S i a x Hexol LS 490, OH equiv 114, polyether, functionality 6, Union Carbide Chemicals Co., S e w York, 3.Y. Xiax polypropylene glycol, PPG 425, OH equiv 205, functionality 2, Union Carbide Chemicals Co., Kern York, N. Y. Carbowax 400, polyethylene glycol 400, functionality 2, Union Carbide Chemicals Co., S e w York, X. Y. Pluracol TP 440, OH equiv 140, functionality 3, B M F / Wyandotte Chemicals Corp., Wyandotte, llich. Pluracol P e P 450, O H equiv 100, functionality 4, B;1SF/ Wyandotte Chemicals Corp., F y a n d o t t e , Nich. Poly01 EOV, a rosin derivative, OH equiv 218, Hercules Iiic., Rilmington, Del. Vinsol, a by-product from bhe wood naval stores industry, Hercules Inc., Wilmington, Del. Surfactant Silicone surfactant DC-193, Dow Coriiing Corp., Midland, hlich. Union Carbide L-5310 surfactant, Union Carbide Chemicals Co., New York, N. Y. Union Carbide L-520 surfactant', Union Carbide Chemicals Co., S e w York, X. Y. Amines Dabco R-8020, Air Products and Chemicals Inc., Wayne, Pa. A7,AT,N',LV'-Tetramet.hyl-l,3-butanediamine, Union Carbide Chemicals Co., S e w York, N. Y. Blowing Agent, CFCl, Freon 11, manufactured by E. I. du Pont de Nemours and Co., Inc., purchased from the Matheson Co., East Rutherford, S.J. Tin Catalyst' Dibutyltin dilaurate, 11and T Chemicals Inc., Rahway, S . J. Equipment Electronically controlled variable-speed paddle stirrer, Curtin Scientific Co., Jacksonville, Fla. Cardboard ice cream cartons (1 q t and 1 gal) Pressure reaction vessels equipped with head consistiiig of needle valve and pressure gauge, Fischer & Porter Co., Warminster, Pa. a All chemicals are listed by trade names, except in two instances.
Industry has been interested in Polyol EOV, in part, because of the high compressive strength of foams attributed to the rigid structure of the resinyl moiety. This apparently is ail acceptable material for rigid foams and experimental evidence has shown it to be bett,er in many respects than the usual commercial glycols made from sugar, pentaerythritol, glycerine, etc. (Darr and Backus, 1967). One of the principal objections to this glycol has been its highly viscous nature (Hedrick, 1969). The resinyl glycols described here should be as good as or better than Poly01 EOV because they give less viscous glycol blends and have a rigid structure like EOV. Over 50% of Polyol EO17 is either di- or trifunctional. llkoxylated OXOInd. Eng. Chem. Prod. Res. Develop., Vol. 1 2 , No. 3, 1973
247
Table II. Foam Formulations-Two Glycols
-
Pep 450 RS 450 Hex01490 TP 440 PPG 425 Poly01 EOV Rosin IIIa Rosin VIb Rosin IVb Rosin IVa
Step
Materials, g, for 1 equiv of polyol blend
A
B
C
D
E
F
G
H
40.13
44.22 71.91
46.30
68.59
60,26
60,96
59.71
62.00
I
65.1
68.47
33.47,15.2 CFC&,g,% Tin compd, g, % 0.34,O.1 Amine,n g, % 0.51,O.15 SurfactantJbg,% 1 . 7 0 , 0 . 5 Viscosity,c CP ( " C ) 530 (25)
73.66 64.62 87.58
88.57 87,79 99.80 92,40 36.27,15.3 0.35,O. 1 0.53,O. 15 1.71,0,5
35.33,15.1 0.51,O.15 0.76,0.22 2.51,0.7
37.51,lj.l 0.37,O. 1 0.56,O. 15 1.85,0.5
745 (25)
192 (25)
112 (25)
3 3 . 0 0 , 1 3 . 5 34.52,13.7 0.30,O.08 0 . 3 1 , 0 . 0 8 0.47,O.13 0.48,O. 13 l . 7 9 , 0 . 5 1.85,O.S
6680 (30)
6520 (30)
3 4 . 5 2 , 1 3 . 7 42.60,15.0 4 1 . 7 , 1 0 . 6 0 . 3 4 0 . 1 5 0.40,O. 1 0.31,O.08 0 . 8 4 , 0 . 2 2 0.60,O. 15 0.47,O.12 4 . 5 3 , 1 . 2 3.60,O.g 3 . 8 9 , l . O 4772 (25)
845 (25)
Treat each of the above compositions with the following reaction mixture: 27.30 g of Pep 450, 144,30 g of AIT 40, 17.20 g of blowing agent; viscosity 2130.0 cP; 1.09 equiv Total foam ingredients, g 333.4 343,8 347.9 362.3 372.2 375.5 a Dabco R 8020. Silicone surfactant DC-193. Determined by ASThI D 856-49 procedure. nated rosin and formaldehyde-modified rosin have similar functionalities. The glycol esters I I I a and I I I b and the glycol derivatives IVa and IYb are only difunctional and resemble polypropylene glycol P P G 425, except for the rigid resinyl nucleus in the polyglycol chain. The formulations were devised so that, in the one-step process, 55% of the glycol could be replaced with any one of the other glycols without other changes. I n the two-step method, 50% of the glycols were interchanged nithout other changes. I n this way, any resinyl glycols could be compared with any one of the other glycols. Deviations in CFC18, surfactant, and catalysts were required, as noted, in order to control foam properties such as density and cell size. By necessity foams 1% ere made by hand mixing. Compres4ve strengths and densities were determined in-house and all other testing was done by a commercial laboratory. Foam formulations and results are tabulated in Tables 11-IT. Experimental Section
The following abbreviations are used : neutralization equivalent, neut equiv; saponification equivalent, sap equiv; hydroxyl equivalent, OH equiv; lolver methanolic layers, LI. Lz, etc.; upper hexane layers, U1, U2,etc.; gas-liquid partition chromatography, glpc. Ethylene Glycol Ester (IIIa). 12-Hydroxymethyldihydroabietic acid (I) was prepared by the procedure of Lewis and Hedrick (1970). Crude acid, 38 lb [by glpc this contained approximately 10% unsubstituted resin acids and I, which was a mixture of hydroxymethyldihydroresin acids, neut equiv 336; OH equiv (methyl ester) 3771, was dissolved in 8 gal of dry dimethylformamide (DAIF). -1fter flushing the reactor well with nitrogen to exclude oxygen, the batch was heated to 210-215°F and a n ethylene oxidenitrogen mixture was passed through the solution a t a rate to maintain slow reflux of oxide. K h e n the acid content dropped to zero, ethylene oxide was added for 1 additional hr; then most of the DlIF was distilled a t 212-215°F (9 cm). The residue mas cooled, dissolved in 12 gal of benzene, washed a t 160°F first with 1 S HC1 to remove any dimethyl248
Ind. Eng. Chem. Prod. Res. Develop., Vol. 12, No. 3, 1973
376.8
397.9
393.2
amine present, then with 1 -I' KaOH, 1 S HC1, and finally with water. The benzene was distilled, stripped under 6 cm pressure, and sparged a i t h nitrogen with 9 em pressure, yielding 43.0 lb of uiipurified brown resin: OH equir 227.8, sap equiv 370.6, acid number 2.0, ball and ring softening point (SP) 65-66'. h composition consisting of glycol dihydroabietate (lo%), a glycol ester of a polyester dimer of I (20%), and a glycol ester of I (70%) would have a calculated sap equiv of 370 and OH equiv of 220. Glycol IIIb. rlcid I (crude as above), 600 g, mas dissolved in 1100 ml of d r y D N F , flushed with nitrogen, a n d ethylene oxide was bubbled through the solution held a t 100' while maintaining a gentle reflux. Oxide addition was stopped [Then the titer indicated only a trace of unreacted acid. Unreacted acid ( 5 g) \vas removed later with alkali wash. The batch was washed and isolated as in the preparation of I I I a above, yielding 626.5 g of amber-colored resin: sap equiv 354.5, OH equiv 203.5, acid number 0, SP 45". Ethylene Glycol Ester of Formaldehyde-Modified Rosin (VIb). Rosin was treated with paraformaldehyde in a n acetic anhydride-acetic acid mixture and isolated in accordance ivith Rohde, et al. (1973) : neut equiv 396.7, O H equiv (methyl ester) 310, sap equiv (methyl ester) 388.3, 1.25 equiv of OH/equiv of ester (on this basis the neut equiv should have been 374.3), less t h a n 2% volatiles when sparged with steam (mostly terpenes, odor of chavicol). h part of the above resin, 45 lb, was dissolved in 7 . 5 gal of dry DAIF and treated m-ith ethylene oxide as in the preparation of I I I a above, yielding 49.3 lb of dark brown resin: S P 64-65", sap equiv 432.9, OH equiv 214. Ethyene Glycol Ester of Aqueous Methanol Extract (VIc). Aqueous methanol (15% HzO by volume) a n d hexane mere mived to equilibration (each layer saturated with the other). The formaldehyde-modified rosin above (313 g) was dissolved in 3000 ml of aqueous methanol. Hexane (3000 ml) was placed in each of six separatory funnels. The methanol solution was added to the first funnel, mixed well, and allowed to settle; the lower methanol layer was transferred to the second funnel and the operation was
repeated through the six stages. Equilibrated aqueous methanol (3000 ml) \vas added to the first funnel, mixed, separated, and transferred to the second funnel, then to the third, etc. I n the end, there were sir; upper hexane layers and six lower methanolic layers. Three extractions were made using 939 g of formaldehydemodified rosin. The first three lower layers of the first extraction aiid t h e first two lower layers of t h e other two extractions were combined. The solvent was distilled, and t h e residue was dissolved in benzene and washed hot, 70", with water t o remove traces of methanol; then t h e benzene was distilled and finally stripped at 150" (0.1 mm). A dark brown resin was obtained, 535 g : neut eqiiiv 386.5, OH equiv (methyl ester) 263.6, 24.9 g of OH, 1.48 equiv/equiv of acid. T h e resin from the combined other lower layers was similarly isolated, 57.6 g: neut equiv 370, OH equiv (methyl ester) 540. Removal of t h e hesane from t h e combined upper layers gave a n ambercolored resin, 301 g: neut equiv 370, OH equiv (methyl ester) 2550.0. The methanol extract, 487 g, was dissolved in 1 1. of D M F aiid treated a t 100" with ethylene oxide as above (acid left by titer 20.0 g). Isolation from benzene, 150" (0.1 mm), after a hot alkaline wash as in the preparation of I I I a above, gave a dark brown resin, 482.3 g: OH equiv 175.1, sap equiv 432.1 (2.46 equiv of OH/equiv of acid, approximately 1-mol addition of ethylene oside), SP $3". Ethylene Oxide Reaction with 12-Hydroxymethylabietanol (IVa). 12-Hydrosymethylabietanol (11)) 322 g (1 mol), and 900 ml of d r y diosane were added t o a rockingtype pressure reactor and cooled t o below 10". Solid potassium hydroxide, 3 g, aiid 220 g (5.0 mol) of ethylene oxide were added to the cooled solution and air was excluded b y blanket'ing wit'h nit'rogen. The reactor was closed a n d heated to 140" for 4 hr, maximum pressure 550 psi. T h e batch was cooled to room t,eniprature. Dioxane was distilled, and t'he residue was dissolved in 3 1. of benzene and mashed hot' (70") with 3 A' HCl and water t o remove KOH. After standing overnight, a colorless solid had precipitated, 78.7 g, and was removed by filtration. The benzene was distilled from the filtrate and the residue was stripped a t 125" (0.2 mm) t o give 420 g of amber-colored, viscous liquid. Anal. Calcd for 4.82-mol alkoride addition, C30.6H57.306.82 (fractions in t h e empirical formula vary in accordance with the amount of alkyleiie oside added): C, 68.7; H, 10.7; 0, 20.4; OH equiv 267.04. Found: C, 69.04; H j 10.92; 0, 20.6; OH equiv 267.3. The solid had a melting point of 179-180" (from benzene) and was the monoglycol ether of 11. Anal. Calcd for C23H4203: C, 75.34; H, 11.57; OH equiv 183.16. Found: C, 77.55; H, 11.57; OH equiv 181.7. Propylene Oxide Reaction with I1 (IVb). Glycol 11, 322 g (1 mol), propylene oxide, 232 g (4 equiv), diosane, 600 ml, a n d solid K O H pellets, 4 g, were allowed t o react in accordance with Lewis a n d Hedrick (1970). Upon removing t h e benzene by dist,illing and stripping a t 150" (0.2 m m ) , a light' yellow, viscous liquid mas obtained, 541.5 g, 3.54mol addition of propylene oxide. Anal. Calcd for CSl.6H59.205 (fractions in the empirical formula vary in accordance with the amount of alkylene oxide added): C, 71.97; H, 11.33; 0: 16.70; OH equiv 263.4. Found: C, 71.16; H, 10.74; 0, 18.10; OH equiv263.9. Propylene Glycol Ester of Oxonated Rosin (Va). 0x0nated rosin made from unest,erified rosin, 145.5 g (neut equiv 417, sap equiv 344.8, O H equiv 396), in 200 ml of D M F and propylene oxide (60 g) was treated a t 100" as
CD
W
co
~y
oc r-
X i
r-
W
Z r ri
In
W
as m
Q,
Q,
r-
3
M
* X
Ind. Eng. Chem. Prod. Res. Develop., Vol. 12, No. 3, 1973
249
Table IV. Some Foam Properties and Characteristics of Rigid Foams Derived from Commercial Glycols and from a Mixture of a Commercial Glycol and Rosin Polyol Evaluation tests (determined b y ASTM procedures)
Foam
Glycol
Compressive strength: psi; yield, % Parallel Perpendicular
Density,a Ib/ft3
Cream, rec
Rise, sec
Thermal conductivityC
Friability,d Water % wt absorplass/lO min tion,= Ib/ft2
Porosity:
% open cells
Cells per inche
Two Step/
A
Hesol490 RS 450
B
C
D E
F G H I
TP 440 P P G 425 Polyol EOV Rosin Rosin Rosin Rosin
IIIa VIb IVb IVa
2.28 2 09 2 13 2 05 2 13 2 12 1.97 2 04 1 97
48.0; 10.1 15.2; 8.3 47.1; 9.15 16.9;9.2 44,9; 8.8 1 0 . 2 ; 7 . 8 35,7;11,2 10.2; 7,l 48,7; 7.8 13.7; 8.2 37.0;9.2 13.3;6.43 7 , 7 12.4;T.O 44,6; 29.1; 9.3 13,l; 7.5 21,6; 8.0 13.5; 7.1
40 45 30 35 35 30 25 40 28
129 145 100 115 180 120 175 160 178
0.157 0.155 0.157 0 149 0.158 0.183 0.166 0.197
60 67 60 65 110 100 160 150 135 110 85
0.163 0,171 0.164 0.184 0.166 0.178 0.203 0.183 0.199 0.179
2.22 10.20 0.75 4.81 1.41 4.40 4.34 1.74
0,0486 0.0812 0.0505 0.0682 0.0377 0.0794 0,0424 0.0328
12 12 14 19 14 17 19 24
85 55 105 65
80 85 85 75
30
One Step0
1
Hesol490 RS 450
B C
n E F
TP 440 P P G 425 Polyol EOV
2.09 2.07 2.15 1.98 1.88 1.90 2.01 1.97 2.03 2.09 2.20
45 5 ; 7 8 45 3;6 9 42 5;9 5 34 8;72 42 9;80 35 0 ; i 3 30 5;lO 0 48 0;82 38 3;8 1 22 9;10 4 27 4;120
12.2; 7.6 12.4; 8.8 13.6; 7.2 10.1;6.3 11.6;73 10.5; 6.7 15.3; 7.6 12.3;8.4 12.6;g.O 11.7; 8.1 18.7; 13.6
25 25 20 20 12 25 30 30 30 30 20
3.08 1.90 3.35 1.44 1.39 1.30 3.94 2.18 2.83 2.32
0 0421 0 0335 0 0403 0 0386 0 0315 0 0363 0 0440 0 0364 0 0368 0 0318
15 18 1i
17 20 17 24 18 19 41
135 125 90 150 130 80 60 85 80 115 75
Rosin I I I a Rosin I I I b Rosin VIb Rosin VIc J Rosin 11% K Rosin Va a ASTRI D 1667. ASTN D 1621. ASTN C 518; units BTU in./hr ftz "F. ASTRI C 421. e ASThI D 1940-G2 T. Glycols from Table 11. 0 Glycols from Table 111.
G
Table V. Formulations Showing Differences in Viscosities of Some Polyol Blends for the Two-step Process Materials, g, for 1 equiv of polyol blend
P e P 450 Polyol EOV Rosin IIIa Rosin VIb Blowing agent Tin compd Amine Surfactant Viscosity, cP (25')
59 80 87 20
61 10
59 40
88 80 48 10 0 32 0 50 1 99 5350
49 50 0 32 0 50 1 90 2677
86 60 47 80 0 32 0 49 1 88 3020
in t h e preparation of I I I a . d brow1 resin (165.0g) was obtained, OH equiv 268. Preparation of Polyol Blends. The polyol blend iiigredients in Tables I1 and I11 were added t'o a pressure reaction vessel cont'aining a magnet,ic stirring bar. T h e blowing agent was added last; the reactor was then closed and placed i n a hot, wat'er b a t h a t 80-90' on a hot plate equipped with a magnetic stirrer. K h e n t h e contents melted, stirring was cont'inued until mixing v a s complete. This took about 1 h r ; then the reactor was placed in n water bat'h maintained a t 22-23'. I n instances when foam cell struct'ures were poor, foams G and H two step and G, I, and J one step, Table IV, Union Carbide L-5310and L-520surfactants were tried in place of surfactant DC-193.I n these cases, t,iii catalysts aiid the two amines were varied. These changes had 110 appreciable effect in the cell structure of the foams. Three polyol blends, Table 17, using Polyol EOS' and rosin glycols I I I a and VIh were prepared and were similar to poly01 250
Ind. Ens. Chem. Prod. Res. Develop., Vol. 12, No. 3, 1973
blends E, F, and G, Table 11. The viscosities were taken for comparison of the three polyol blends. Foams were not made. Preparation of Quasiprepolymer. The isocyanate LIT 40 arid t h e polyol P e P 450 were allowed t o react in a flask at 70-75'. When reaction mas complet,e and cooled, CFC13 was added and stirred a t below 24'. This reaction also was stored in the water bath, 22-23', Foaming. Sufficient polyol blend and isocyanate t o rnake 200 g of foam were added to a 1-qt carton and niised with a Curtiii paddle stirrer a t about 4500 rpm. When mixed, t h e contents were poured into a 1-gal ice cream carton. Stirring varied from 5 t o 10 see, depending upon viscosit'ies of t h e misture. The most' viscous materials required the longest times After observing time for cream aiid rise, the foams n-ere stored ill the laboratory 3 weeks before making physical tests. The results of the tests are tabulated in Table 11'. Discussion of Experimental Results
Alkoxylation. Kolbe (1959)reported the alkosylation of acids, e.g., terephthalic acid, which involved the addition of alkosides Do a D M F solution of the acid. Lewis aiid Hedrick (1970) found t h a t the hydrosyl group of the hydrosyacid I did not react with propylene oside by this procedure and presumed t h a t when ethylene oxide reacted, only the carboxyl group was involved. -%lthough Kolbe reported the formation of only a monoglycol ester, it was found that in one case appreciable polyosyglycol probably was formed (IIIa, OH equiv 227.8)when the reaction proceeded until all the acid was gone. Less polyosyglycol was formed when the reaction was stopped before all the acid reacted (IIIb, OH equiv 203.5).Except for polyester formation there should be a correlatioii between the OH equivalents and the saponification equivalents. The saponificatioli equivalent of IIIa was much lower than espected and the high
viscosity of the polyol blend suggests polyester formation. Contrary to this are the data for ester I I I b which also has a saponification equivalent lower than expected; although analytical data were checked repeatedly these discrepancies were not explained. The analytical data for glycol esters VIb and VIc agreed more closely. The alkoxylation of oxonated rosin by the Kolbe procedure gave results similar t o those described for I I I a above. The ethoxylation of the glycol I1 was disappointing in t h a t one of the hydroxyl groups apparently reacted more readily than t h e other and about 5 mol of ethylene oxideimol of glycol was required t o avoid substantial yields of t'he monoglycol ether. Because of the high melting point, 179-180°, and poor solubility, t h e latter was of no value for the polyol blends or prepolymers required for rigid foams. Previously, Lewis and Hedrick (1970) had determined that 4 mol of propylene oxide/ mol of glycol was required to avoid insoluble low molecular weight products. Compositions were studied with commercial glycols to obtain formulations which produced foams having good appearance and cell structure with densities around 2 lb,'ft3 and compressive strengths of about 40 psi. Mixing in the two-step procedure was from 5 t o 10 see wit'h cream times of about 30-40 sec. -4ccept'able foams when produced were sent to a commercial laboratory for det'erminabion of thermal conduct'ivity, friability, water absorpt'ioii, porosity, and cell count (cells per inch). Rigid Foams. Two-step Process. X number of commercial polyglycols were screened for fluidity, processability, a n d compat,ibility with the rosin derivatives t o select materials which would give polyol blends a n d prepolymers fluid enough for hand mixing. The prepolymer containing a n excess of the isocyanate (AIT 40) was treated with the polyol blend which in addition to polyols contained t h e catalysts, surfactant, and CFC1,. The system developed polyol blends and prepolymers which should demonstrate the differences due to the glycols and make possible comparisons with glycols like Voraiiol RS 450, Hexol 490, TP 440, P P G 425, and Polyol
EOV. Catalysts and other ingredients-tin compound ( O . l % ) , amine (0.15%), surfactant (0.5'j&), and CFC1, (15%)-were coilsidered as standard. Catalysts and surfactant witli TI' 440 had to be increased slightly in order to reduce the density of t h e foams to about 2 Ib/ft3. With EOV, the CFC13 and catalysts were reduced to increase t h e density. The foam from Voranol RS 450 was more friable tliaii the other foams probably because of cross-linking and larger cell structure. Otherwise, properties of foams from the three commercial glycols and EOVwere similar. Foams from t h e first five glycols used in t h e two-step process had similar but high thermal conductivity values, probably because of porosity. value of 0.12 B T U in./hr f t 2 O F and 5% open cells would be considered good to excellent. Undoubtedly, porosit'y and heat transfer ITere affected by varying numbers of long cylindrical holes parallel to t'he directioii of rise (0.5-1 mm in diameter and usually no longer than 1 em) in all the foams; these holes probably were caused by air or CFCl, trapped in the liquid during mixing prior t o foaming. The cell st,ructure of foams from the twostep procedure (Tables I1 and IV) was uniform except for foams H and I, discussed later. Water absorption values are inconsistent aiid are not as expected because this property should be related t o open cell content; cf. foanis, B, G , and H. The long cylindrical holes referred to above may have had A \
some effect on water absorption. A11 rosin glycols, including
EOV, had considerably higher hydroxyl values than the three polyols in foams A, B, and C. This should be reflected in foam properties because the higher hydroxyl values required less isocyanate for the reaction; and since the isocyanates used were cross-linked, compressive strengths should be less. Compressive strength of foam F from rosin IIIa was lower than t h a t of foams A, 13, or C but was comparable t o foam D. I I I a was similar to P P G 425 because they are difunctional and have similar chain lengths, 26 and 22 atoms, respectively. Other influential differences in the chemistry of the two materials is in the nature of the alkoxides. Foam compositions having over 50% P P G 425 in the glycol mixture resulted in foams that collapsed before gelling took place. Accordingly, the P P G 425 was reduced to 40% of the glycol mixture and the appearance of the foam was satisfactory. Foams containing 407, polyethylene glycol (Carbowax 400) collapsed and were rubbery. Comparison of I I I a with P P G 425 and Carbowax 400 demonstrated the effect of the rigid resinyl group in the glycol chain. I n respect to chemical structure, functionality, and molecular weight, rosin VIb was similar to Polyol EOV and properties of foams made with these glycols were similar. Glycol VIb, however, gave less viscous polyol blends than EOV. Properties of foams from I I I a and S'Ib may have differed because of the higher funct'ionality of the latter. Formulations including VIb required higher concentrations of catalysts and surfactant than most formulations in this series. Glycols IVb and IVa, used in making foams H and I, differed from I I I a and VIb in several ways. They were polyethers, and I I I a and VIb were esters. Because of differences in synthesis, IVa and IVb had higher molecular weights than I I I a and T'Ib and produced less viscous polyol blends. Good uniform cell structure could not be obtained for some reason with glycols IVa and IVb (two-step procedure) and glycols I I I b , IVb, \'a, and, to some extent, VIc in the onestep procedure. Glycol IVa was not' used in the one-step procedure. Good uniform cell structures could not be obtained for some reason with any of these. Visually, t,he structure consisted of large cells interspersed among many smaller cells. Possibly the large cells formed as a result of cell collapse. Changing the surfact,ant did not correct this condition. Foam H had reasonably good properties, in spite of the high open-cell content. Foam I had large cells and only density and compression strengths were determined. Because foam properties did not respond to variations in composition, further study involving surfactants and/or catalysts probably nil1 be required for solution of the problem of cell structure. One-Step Process. In the one-step foaming procedure the glycols were mixed wit'h the catalysts, surfactant, a n d CFC13 and this blend was treated with a slight excess isocyanate, M R , or, i n two instances, MRS. This procedure gave more fluid polyol blends and was generally more satisfact'ory than the two-step method from standpoints of preparation and performance. Foams A-F and H differed little in foam properties. The thermal conductivity and porosity values were high aiid were similar to the results of foams made by the two-step procedure. These results were attributed to the elongated holes discussed above. Rosin glycol IIIb, which had a lower hydroxyl value than I I I a , probably contained less inter-ester, judging from the lower viscosity of its poly01 blend. -1lthough I I I b was the better glycol of the two, it' produced foams that were unsatisfactory because of poor cell structure. Foam ingredients containing this glycol reacted rapidly with a normal amount Ind. Eng. Chem. Prod. Res. Develop. Vol. 12, No. 3, 1973
251
of catalysts. Of all the rosin glycols, VIc was expected to be the best and might have been if cell structure had been good. Glycols I I I b and VIc were similar in that small catalyst changes were required and large amounts of surfactant were needed. Foams from 1% and Va were poor because of high molecular weights of the glycols and poor cell structures noted earlier. Viscosity data in Tables 11,111,and V are relative and important and show that of the resinyl materials, EOV gave the most viscous polyol blends. The rosin derivatives were more viscous than the commerclal substances probably because the high OH equivalent required higher concentrations of glycol. Generally, less CFC13 was required and the chemical structure of the bulky resin acids contributed to the viscosity of the blends. The polyol blends in the one-step process were less viscous than the blends for the other procedure. Summary and Conclusions
An investigation has been under way to increase the functionality of rosin and resin acids by treating formaldehyde with resin acids in pine gum, by treating rosin with formaldehyde, and by oxonating rosin. These reactions led to introduction of hydroxymethyl groups into the resin acid nucleus and resulted in the formation of a number of new hydroxy acids and glycols, represented by I, 11, Vc, and 1%..Illowing these to react with ethylene and propylene oside produced additional materials, such as I I I a , IIIb, IVa, IVb, Va, and VIb. The products obtained, the initial intermediate reactants, and the final glycols should find uses as raw materials for new resins, adhesives, printing inks, arid other industrial products. T o demonstrate their utility, the alkylene oxide adducts were evaluated as part of the glycol mixture used for rigid polyurethane foams. Rosin glycols were blended with commercial glycols in amounts of 5 0 4 5 % and treated with polymerized isocyanates giving in some instances foams comparable to those from commercial glycols judged by the following tests: foam density, compressive strengths, thermal conductivity, porosity, water absorption, and friability. Formulations from some of the rosin glycols, particularly I I I b and VIc described in the Experimental Section, result in foams having a n undesirable cell structure with properties poorer than expected. Since foam properties did not respond to variations in composition. further study involving surfactants and/or catalysts will be required for solution of the problem. Rosin glycols IVa and IVb and Va also gave foams having poor cell structures.
252 Ind. Eng. Chem. Prod. Res. Develop., Vol. 12, No. 3, 1973
At the time of the initial work reported in this paper, rosin and pine gum were sufficiently inexpensive so that some of the resinyl derivatives had considerable potential for commercial development. I n the last 2 or 3 years, naval stores prices have increased to the point where these derivatives can only be considered as speciality products, because of cost. Roberts (1973) recently has observed that injection of a minute amount of “Paraquat” (a herbicide sold by Standard of California) into pine trees causes the pine oleoresin to flow inward into the center of the tree. The resulting pitch-soaked wood contains considerable naval stores products and rosin can be obtained in good yield-30-40$& of the weight of the wood-by extraction of the chips after the tree has been felled and chipped. Methods for studying tree treatment and isolation of naval stores are being investigated. There is a possibility the above will result in the availability of rosin in large quantities a t low cost and cause a turnaround in the naval stores industry. literature Cited
Class, J. B. (to Hercules Inc.), U. S.Patent 3,541,134 (Nov 1970). Darr, W.C., Backus, J. K., Ind. Eng. Chem., Prod Res. Develop., 6. 167 11967). Ilelmonte, D. ’W. (to Hercules Inc.), U. S. Patent 3,356,622 (\ -D e - -r 1967)
Gemeinhardi, P. S., Door, W.C., Saunders, J. H., Ind. Eng. Chem., Prod. Res. Dmelop., 1, 92 (1962). Hedrick, G. W., ARS Report 72-77, “Proceedings of the Conference on Kava1 Stores Products,” pp 28-36, Agricultural Research Service, USDA, New Orleans, La., 1969. Hedrick, G. W.,,private communication, 1970. Hercules Technical Data Bulletin PC-187, Hercules lnc., W11mington, Del., 1967. Hudson, G. A. (to Mobay Chemical Co.), U. S. Patent 3,09.5,386 (June 1963). Kolbe. K . E. (to Standard of Indiana), U. S. Patent 2,901,.505 (Auk 1959). Lewis, J. B., Hedrick, G. W.,Ind. Eng. Chem., Prod. Res. Develop., 9, 304 (1970). Roberts, I>. R., Note SE-191, Saval Stores and Timber Production Laboratorv, Forest Service, USDA, Olustee, Fla. 32072, April 1973. Rohde, W.A., Black, D. K., Hedrick, G. W.,Ind. Eng. Chem., Prod. Res. Develop., 12, 241 (1973). Rummelsburg, A. L. (to Hercules Inc.), U. S.Patent 2,535,901 (June 1961). Saabot, J. F. (to Mobay Chemical Co.), U. S. Patent 3,236,790 (Feb 1966). RI:CEIVED for review April 16, 1973 ACCEPTEDJune 11, 1973 Mention of commercial products is for identification only and does not constitute endorsement by the U. S. Department of Agriculture over those of other manufacturers.
