Document Rjy3XG5G07xdMdxpeY7GG8jma

"Classification of Souse Faints" 4^9 Technical &alletln Vo. 804 "Classification of Bouse and San Faints* was issued 1ay tho United Statss Otpartasnt of igriculture in January, 1942. It offsrs a sfstsa of elaselfleatloa of such paints according to group, typo and grade based on calculations of voluae compo sition dsrlTsd frea label analyses declaration. The systsa Is offered as an aid to tbs consuaer in tho ssloetlon of paints of quality suitable for tho purpose Intended* Xt is stated that swan whan analyses (by weight or toIubo) appear on the label* the consuaer does not haws sufficient knowledge of their significance to pezalt bia to estlaate ths quality of the paint. Group* classifies paint according to plgaent composition* vis. SLZ refers to a titanius>-lsad-sine paint* L a lead paint such as lead^-laoil, IZ a lsad*>frso titaniumsine paint* ate* The phraseology becoaes aore obsenre when the syabols used include 8 for sine sulfide* F for iron oxide and C for other eolored pigsoats* If the vehicle contains 15^ or aore by voluae of bodied oil* as would hold for aost aodem house paints* the group classification apy be extended by adding the syabel (o) e*g* SLZ. (e). This would identify the paint as an "enaaellsed paint** which is not a suitable designation* Sodded oil paints* would be aore descriptive* but is given only as an sxaqple of preferred ndasnelature* Label analyses* if given by weight* are recalculated to determine opaque pigments* extenders* oils* driers end thinners in terns of deeiaal fractions of a gallon (l*e* by voluae)* Opaque pigaents of aore then aver age opacity* such as titaniua dioxide* sine sulfide* etc. in the white pig. asnts* and sons eolored pigaents are given the benefit of a special *diluent allowance* in calculating the total pliant voltae* The paints are then classified into "type* according to how auch lead and sine appears in the plantation (shown as a nuaeral) and the ratio by voluae of lead pigment to sine oxide (shown as a letter)* "Grade* is then signified in the sene# of classifying the quality of the peint* "Grade* is rated tmm 1 as ths highest to 5 (or 6) as ths lowest* Steh grade requires that opaque pigaent voluae (equivalent), total actual pigasnt voluae* and total non-volatile (voluae of pigaent plus extenders plus voluae of non-volatile binder) pass certain aintnuas* Thus, a aodem bouse paint night be classified net Group SLZ (e) 5ype 4c Grade 2 Xt ie our eoneidored opinion tbat a sequence of syabols of this sort are no aore intelligible to tbe avenge buyer then current label analyses* and in all probabilities* less intelligible. Xt is aore than probable* however* tbat ba will disregard ths confusing "group" and "typo* N 4368 NPC 000908 symbol* aad will focna all hit attention on "grade,* and ataoat that Ormda 1* it hattar thaa "Grad# 2,* aad ao on. Bagardlass of tha inten tions, thla will ha tha natural aad probla raaolt. in? system of classification haaad oa formulation (aad we eaa eoacelva of ao system which mold not ha haaad oa formulation) la restrictive oa progress aad raaearch. Tha system as propossd ia Taehnlcal Bulletin So. 804 la not only aonscsasary hut lta premises havs bacons obaolsts and actually ara scientifically unsound. Za addition to being highly unfavorable la lta poaalbla iafluaaea oa future resaarch, it would la any final analytic misinform tha public aa to sound aad valid orltarla by which to Jud^e tha paxfomaaea of palata. Zhaa it would fail la tha vary paxpoaa for which it la intended* Zt la apparent that thla failure- etaae largely from a failure to conduct auffldontly exhaustive axaainationa aad axposura taatt over tha past tan years or aore to keep abreast of tha advances la anterior paint technology. Thera ia ao recognition of the considerable improvement ia appear ance and durability eharactarlstlea accomplished during thla period. Zt over look* tha lsprovsaent In flow, drying, reduction of .dirt retention, maintained batter appearance and greater durability arising froa the us* of larger aaounts of bodiad oila and lever binder ratalting from the oil conservation order K-332 in 1943. Za fact, grade la adversely affected by the rules of classification act up la Technical Bulletin So. 804 if tha female la sat tqp to incorporate tha factor* of vehicle composition which have lad to tha u* provanaat la house paints through tha oca of bodied ell vehicles. This la an example of the dangers of any system of classification based oa composition as being restrictive on research. Vo one eaa predict what tangent research and development may taka la finding new aad novel formulations leading to better paints redounding to the benefit of the public. The classification system sat up la Technical Bulletin Vo. 804 gives misinformation aad is technically unsound for several reasons, of which we will mention only a few. Zt is passible, for avampl*, to formulate two TLZ paints of identical chemical coapoalien (and therefore identical classifica tion) which, dependant only cm the selection of the sine oxide used, uould vary ia durability from L-l/2 - 2 years op to 5 7*ere Different extenders or different oils eoold affect performance equally aa much. Calelam carbonate extenders aa aa iT--pTs most be chosen with great care aa their origin, re activity, particle rise, etc., have a considerable bearing oa tha durability of paints in which they are used, especially ia white house paints. There are certain well recognised types of formulation which would rato as Brad* 1 paints although It is universally roeogaisod that they aro considerably inferior to modem paints %Aleh might rats *Ormda 2* or aOrado 3a in tha proposed elasslfeatloa. Pigmentations containing high percentages of llthopono or sine sulfide pinouts aro not suitable for omtorior bouse paint formulations booauao of checking, cracking or erosive tendencies, but could rato Orade 1 classification. Uaay other similar example* eoold be given aad we are attaching photographs of three eats of panels which illus trate how palate of identical chemical composition may vary ia quality because of different physical characteristics cf only one of tha components In each case. Therefore, a 'Grade 1* classification would give no assurance of NPC 300909 3servic# tad satisfaction to consumers and could aislead purchasers depending on this government sponsored infomation* The system is tochnically onaoond - la ita very flrat tanat It assigns a fixed opacity for each opaque pipmsnt* It haa beta establisbBd that opaque pigments can anally raiy 200 - }00f la hiding powar, dapending oa their "hiding plgaaat velum# concentration," l.e., tlm par cant of the total pifliaat, extender and vehicle solids volume occupied hy the Individual opaque pigments, Therefore* It la scientifically uneound to assign a single opacity figure for any given pigeent* The system la farther onaoond in that it equates active pigaente on the basis of volute* whereas it la known that reactivity is related to surface area* crystal configuration* etc* It la not valid to say that all lead carbonates are equal* all sine oxides'tqual, and so on* Proper consideration of the tremendous voluas of research and test ing which has been carried cut on all phases la exterior paint technology in the past ten years alone would shew how unfortunate it would be for a governneat agency to further sponsor this aystea of paint classification* Xt will be to the advantage of the consuaing puhlio to withdraw further promotion of this idea* NPC 00091)