67  US 6,391,949 B2  68  of TEXANOLfi (2,2,4-trimethyl-1,3-pentanediol, Texaco)  andARCOSOLVEfi TPM (tripropylene glycol methyl ether,  AtlanticRichfield).  0.45 gram of the test stabilizer is predissolved in 10 g of  the cosolvent blend which is then incorporated into the  following composition:  mer with acrylonitrile and the copolymerization of stryrene  monomer with butadiene, generally referred to as  ABS,  are  dry blended with the instant compounds and melt com- pounded into pellets. Typical formulations contain the  instant compounds at levels from 0.05% to 2.0%, a metal  stearate such as calcium stearate at 0.05% to 0.5%, pigments  from 0% to 5%, UV absorbers at levels of 0.05% to 2.0%,  phosphites at 0.0%-0.1 %, phenolic antioxidants at  0.0%-1.25%, N,N-dialkylhydroxylamine at 0.0%-0.1 %,  and optionally other hindered amine stabilizers at levels of  0.0% to 2.0%.  The pelletized fully formulated resin is then processed  into a useful article such as extrusion into sheet, film, profile  and pipe; molded into bottles; injection molded into a  molded article; thermoformed into molded articles; or rota› tional molded into hollow articles.  The materials containing the instant compounds exhibit  stability against deleterious effects of UV light and thermal  exposure.  Each coating is brush applied onto 6"x6" sections of cedar  and pine boards. The weight of the coating applied is  regulated by weighing the coating and brush before and after  application and ensuring that the same weight of coating is  applied to each section.  The coated board sections are allowed to dry at ambient  temperature for two weeks, then evaluated for visual  appearance, gloss and Hunter L *, a* and b* color. The  sections are exposed on racks at a 45°  angle in South Florida  for six months before being returned and evaluated for  visual appearance, gloss, color change and any other signs of  degradation or delamination.  The instant hindered amine compounds substituted on the  N-atom with an  -O-E-OH  moiety provide better stabi› lization efficacy to the sections in respect to visual  appearance, gloss retention, resistance to color change and  to delamination than do the corresponding  -NOR  com› pounds lacking such a hydroxyl moiety.  pKa  Values  In order to determine the  pKa  values of water insoluble  materials, organic references with known  pKa  values in  water are titrated non-aqueously. A plot of the half neutral› ization potential  (HNP)  versus the known aqueous  pKa  value of the reference material is establed. The  HNP  of the  test material is determined and extrapolated to find the  corresponding  pKa  value of the test material. Such organic  reference materials include 2,2,6,6-tetramethylpiperidine;  4-hydroxy-2,2,6,6-tetramethy lpiperidine; 1-hydroxyethy l-4- hydroxy-2,2,6,6-tetramethy lpiperidine; triacetoneamine and  N-methylaniline.  The reference materials, which are structurally at least  peripherally related to the instant test materials and are  soluble in both water and 1: 1 acetonitrile:chloroform, are  used to make a calibration plot in the non-aqueous titration  (1: 1 acetonitrile:chloroform solvent and 0.lN perchloric  acid/dioxane titrant) system. Approximately 0.5 milliequiva- lents of test material is weighed into a titration beaker. Thirty  mL of acetonitrile is added to dissolve the sample. Prior to  titration, 30 mL of chloroform is added. Titration is carried  out and the  HNP  is determined. The electrolyte for the  reference electrode is 2-(aminomethylpyridine. The elec- trade is allowed to stand in the solvent system for two hours  after filling with the electrolyte to achieve equilibration. All  samples are run in duplicate. The  pKa  values are seen in the  table below.  Stabilization of Pigmented Automotive OEM  Basecoat  A basecoat pigmented with a mixture of Pigment Red 177  and mica is stabilized with 1 % by weight of a hindered  amine stabilizer based on the total basecoat solids (pigment  plus resin). The basecoat is spray applied at a dry film  thickness of 1 mil (25 microns) to primed 4"x12" steel  panels, then topcoated with a high solids commercially  available automotive clearcoat. The coated panels are cured  in an over at 250°  F.  (121 °  C.) for 30 minutes. The panels are  then exposed in a Xenon-Arc Weather-Ometer under the  following conditions:  Cam 180 cycle: 40 minutes light only; 20 minutes light  and front spray; 60 minutes light only; 60 minutes dark and  rear spray condensate.  Lamp filters are: quartz inner/borosilicate S outer.  Irradiance: 0.55 watts per square meter.  20° Gloss, Distinctness of Image, Hunter Color Space  Values (L *, a*, b* and li.E) are measured before exposure  and after 3000 hours of exposure.  The instant hindered amine compounds substituted on the  N-atom with an  -O-E-OH  moiety provide better stabi› lization efficacy to the panels in respect to distinctness of  image, gloss retention and resistance to color change than do 60  the corresponding  -NOR  compounds lacking such a  hydroxyl moiety.  ABS Molding Applications  Thermoplastic materials composed of mixtures of copoly› mers derived from the copolymerization of styrene mono- *I is the compound of Example 73.  II is 1-cyclohexyloxy-4-ocatadecanoyloxy-2,2,6,6-tetramethylpipendine.  III  is the compound of Example 2.  IV is bis(l-octyloxy-2,2,6,6-tetramethylpiperidin-4-yl) sebacate.  V is the compound of Example 50.  VI is the reaction product of 2,4-bis[N-(1-cyclohexyloxy-2,2,6,6- tetramethylpiperidin-4-yl)butyl-amino ]-6-chloro-s-triazine with N,N’-bis(3- aminopropyl)ethylenediamine.  As  can be seen from each of the above pairs of related  compounds where the individual compounds differ from the  Sample*  HPN (mv)  Calculated pl(,  523  3.9  II  436  4.9  III  513  3.8  IV  4.6  V  3.8  VI  4.8  EXAMPLE 113  EXAMPLE 112  EXAMPLE 114  FLEXTHANE  fi  630 (Air Products)  Foamaster VF  Water  TEXANOL/ARCOSOLVE/hindered amine  UV absorber (TINUVIN  fi  1130, Ciba)  BYK 346  MICHEMLUBE  fi  162  ppw  100.0  0.1  10.0  10.5  1.2  0.5  2.0 