I
ROY W. TESS, RICHARD D. HARLINE, and THOMAS F. MlKA Shell Development Co., Emeryville, Calif.
1,2,6=Hexanetriol in Alkyd Resins b Compared
to glycerol, hexanetriol
cause glycerol is the poly01 mosr Lvidely used in the manufacture of alkyds, it is used here as a standard of comparison in drying and films are softer but for the study of hexanetriol. Glycerol much more flexible. Films have excelhas a n equivalent \it is evident that thc viscosity of Iiexanctriol alkyds is considerably less than that of glycerol alkyds, as shoirn by alkyds a t 50% in mineral spirits (kauri-butanol value 44). O n the other hand, i t is shoivn in Figure 4 that hexanetriol alkyds can be formulated (alkyd 3) to yield higher viscosity if desired. Dehydrated castor alkyds \\.ere prepared a t 230' C. in all cases! because a t higher temperatures it is very difficult to control the reaction a n d to avoid gelation with alkyds of such short oil length. Details o n the progress of the reactions are shown in Figures 5 a n d 6. I n the case of the coconut alkyds (Figure 7 ) , a temperature of 230' C. was used except when the constant phthalic method of using hexanetriol was employed (alkyd 9). I n this case it was necessary to lower the temperature to 220" C. a n d raise the excess of poly01 to avoid gelation.
376
Applications of Medium Soybean Alkyds Soybean modified alkyds of medium oil length have a diversity of uses, such a s in architectural enamels, trim a n d trellis paints, a n d implement a n d a u t o refinishing enamels. They may also be used in combination Lvith sinal1 quantities of amino resins in bakcd finishrs. as for automobiles; althoiigh this application has not yet been explored in the case of hexanetriol alkyds, i t appears to offer considerable promise, as indicated by the favorablr: results \\.it11 dehydrated castor hexanetriol alkyds. In preliminary tests upon clear films, it \cas evident that f i l m of hexanetriol
Table 111.
Film Properties of White Enamels Mode from Medium Soybean Alkyds Type o f. . l l h.. y d iri \
~
~
~
11 i i i
c:lyccl.ol .\lkyd 1. 'l.al11e
Drying time" Set touch, minutes Cotton-free, hours Dried hard, hours Sward hardness, 1 week dry Outdoor exposure, 12 months Gloss Gloss after light washing and polishing Chalking Checking or cracking Outdoor exposure, 18 months Gloss Chalking Checking or cracking
e:
I1
55 12
5 17
~~
' ~ ~ 1 1 111 1 ~ ~
105 6 56
UI62 >62 15 >62 >62 Pass Pass Pass Pass Flex, '/s-inch mandrel Pass Pass Pass Pass Heat-aged films, 72 hr., 95O C. Pencil hardness B HB H 3H 2H Impact, inch-pounds 10 47 >62 >62 >62 Pass Pass Flex, l/s-inch mandrel Fail Pass Pass Moderate Slight Yellowing Moderate Moderate Slight Overbaked films, 1 hr., 177' C. 0 0 4C-62 >62 15 Impact, inch-pounds >,62 >62 Pass Pass Pass Pass Flex, l/a-inch mandrel Pass Pass Pass Moderate SI-mod Slight S1-mod Slight Yellowing Moderate Slight Aged baked films, 16-18 months H H H B HB HB HBf H Pencil hardness 0 0 0 >62 >62 >62 151 Impact, inch-pounds >62 Fail Fail Fail Flex, '/a-inch mandrel Pass Pass Pass Passf Pass a Beetle 227-8, American Cyanamid Co. Titanox RA, Titanium Pigment Corp. Films sprayed on cold-rolled steel were baked at 162' C. (325" F.) for 12 minutes. Generally similar results were obtained at a bake of 20 minutes. Film thickness was 1.0 to 1.3mils. Pencil hardness was taken as the hardness of the hardest pencil which would not scratch the film. In increasing hardness, pencils are . .2B, B, HB, F, H , 2H e A weighted steel ball, S / r inch in diameter and weighing 1.59 pounds, was dropped on the back side of coated panels from heights up t o 100 cm. Impact resistance is expressed as the maximum force in inch-pounds which did not rupture the film. f Film aged 10 months.
... ... ... 9 . .
... ... ... ...
... ... ... ...
... ... ...
Table V.
Properties of Baked White Enamels from Coconut Alkyds and Amine-Formaldehyde Resins" Coating No. 1 2 3 4 5 6 7 8 9 10 Type of Alkyd in Vehicle Glycerol, Comm. Comm. Hex. Glycerol, Comm. Hex. Hex. Hex. Comm. Alkyd Alkyd Alkyd Alkyd Alkyd Alkyd Alkyd -4lkyd Alkyd Alkyd No. 7 A* Bb No. 8 No. 9 No. 7 Ab No. 8 No. 9 Bb 1 Type of Amino Resin Urea Urea Urea Urea Urea Melamine Melamine Melamine Melamine Melamine 26% amine resin in vehicle Pencil hardness B HB HB 4B HB B HB B F HE! Flex, l/s-inch mandrel Pass Pass Pass Pass Pass Pass Pass Pass Fail Pass Impact, inch-pounds 22 0 6 >62 >62 0 0 10 0 >62 Grease, softening Mod Mod Mod Mod None Mod None Mod Mod None s1 s1 S1 bl MIBK, softeningd s1 s1 S1 bl S1 bl SI bl s1 S1 bl 36% amine resin in vehicle HB 2B H Pencil hardness HB HB HB F HB B H Flex, l/n-inch mandrel Pass Fail Pass Pass Pass Fail Fail Fail Fail Pass 3 Impact, inch-pounds 16 0 >62 6 0 0 0 0 >62 Grease, softening Mod Mod None Mod Mod None None None None Mod s1 s1 MIBK, softening s1 Mod None ql bl Mod None Mod None 50% amine resin in vehicle Pencil hardness HB HB H B R H H H H B Flex, '/p-inch mandrel Pass Fail Fail Pass Fail Fail Fail Fail Pass Fail Impact, inch-pounds 0 0 0 10 0 16 0 0 0 0 Grease, softening Mod None s1 Mod None Mod None None None None MIBK, softening s1 None s1 s1 None None None Mod None s1 64% amine resin in vehicle Pencil hardness HB H H HB H H H H H HB Pass Flex, '/s-inch mandrel Fail Fail Fail Fail Fail Pass Fail Fail Fail Impact, inch-pounds 0 0 0 0 0 0 0 0 0 0 Grease, softening Mod None None s1 None None None None Mod None MIBK, softening Mod None s1 s1 None None s1 None Mod None 91, slight. B1, blisters. Mod, moderate. a Enamels 1 to 1.2 mils dry thickness on bonderized steel were baked 30 minutes at 300' F. Pigment-vehicle ratio was 0.8:l using rutile titanium dioxide (Ti Pure R610,E. I. du Pont de Nemours & Co.). Urea-formaldehyde resin was Beetle 227-8 and melamine resin was Melmac 245-8 (both of American Cyanamid Co.). * Commercial alkyd A is specified to contain 44% phthalic anhydride and 32% coconut oil; alkyd B, 39% phthalic anhydride and 37Yc coconut oil. Synthetic grease composed 50% of olive oil and 50% of oleic acid was placed on the film for 72 hours Softening was judged qualitatively by scratching with pencil points. Methyl isobutvl ketone was placed on the film for 15 min. Softening was judged qualitatively by scratching with pencil points.
VOL. 49, NO. 3
MARCH 1957
377
