Document ymvXYxb8MxQv9JbDd6LDx37wr

I---it group of blanks punched from phenolic retin board. When molded, they willformparts ofexceptional" itrohgib. t--Army matt kit knife hat a handle molded from two matching blanks ofphenolic resin hoajd New uses for phenolic resin board EW wartime applicationsof phenolic resin molding board material, "higher mechanical strength may be obtained, .but Nand blanks ore calling attention to the potentialities of this, lowers flow, finish, and water-resistant characteristics these products, where impact resistance is a requirement.' proportionately. ' Either.fast-curing or slow-curing types of As for back as 1932 they were demonstrating their adapta resins' can.be used, thus.stil! further increasing the' diversity of bility to.ah important number of.industrial applications, and today when the major requirement in practically all types of relationship between properties. V.v- . Molding blanks or boards may be used alone in producing phenolics is high impact strength, industry is rediscovering theirunique properties. ., the finished product, or they may be employed in conjunction with standard types of phenolics to provide reinforcement at Best known of the group is phenolic resin molding board, vital points. Frequently parts that are subjected to mechani which is classed as a medium high impact material, with im cal shock require color, surface electrical properties and other pact strength of 185-1.2 on A.S.T.M. Izod test. Its tensile, characteristics not obtainable with molding blanks alone. flexural and compressive strength is unusually high for a ma- .venal with such' outstanding impact resistance. It is pro- 3--Diced or macerated resin board is granular in - duced by combining various types and quantities of resin and structure, has high impact strength, low hulk factor. 'fibrin on paper-making equipment. The resulting boards Surfaces uf artiefes maided from it look like those are then supplied in various size sheets or more generally in of phenolic pieces, although pressures required are ahapu cut to the approximate design of the .finished part. Since these blanks, as they are called, are virtually preforms, relatively .law'and temperatures cf 290a~310a adequate they, can be loaded directly into the mold. . .. Moat unusual characteristic for an impact-resistant pTastic, however, is the low hulk factor of 1.5-1.0. This makes it. ' poasible to fabricate' finished ports in molds designed for .. genenl-^tapose" phetiolics,' Since wartime service demands that fritting product designs be adapted to materials tougher than those.used in.the post, it is often necessary to make the . change immediately. Where.as.fabric-filled impact-resistant ` materials would require deeper and stronger molds to ac commodate greatly increased hulk factor and molding pres sures. the use pf molding boards or blanks requires ha change in molds, and only minor modifications in technique. .. . - Different types of board offer a variety.of combinations of ^mechanical and flectfcal strength, surfaqe'appeafarice, flow and moisture resistance.. By'Ipwering the lesin content of the . MODHSH KdistlCS ' mmm - In such instanc .the outer matet Resin board parts--cams,' i strength. Mol toughness whei free-flowing gr: pieces as small fully. . While i minimum flow, those of genera Newest and board family i` strength of .33though 3 to 41 the general-pur formed on both Cut to pass U. f the hoppers of eral-pnrpose m water resistance stsuidard types known; Its su - parable to that V Tensile stren; new diced mob flexural strengt after a stahdar .40-.9Q percent disk molded fro . .. gain ofjl.9.perc .. ; 125 volts per m X 105 megohm properties, how If, dielectric streng subjecting char; to molding. An important tivety low bulk board materials general-purpose Fabric-filled im; mand extra dec . and more adeqi Furthermore, tl saty with fabric strongerconstru Molding pressu relatively low-- . peralures of 29C Diced resin b - . cations where i fabrication are; matters df .soun: . ; large circuit bre ,. 4--First step . phenolic resin to approximate are then' dam . operation 'after preparation. from' flat sia ' .- l--Headband >  In such instances the blanks may be used merely as a core for ' the outer material, a combination impossible without blanks. . ;. Resin .board is especially desirable where small inotded parts---cams;'.for instance--must "have high mechanical . strength. Molding powders or preforms lack the desired toughness when fabricated into tiny sections. By using'a free-flowing grade of resin hoard, however, impact-resistant ` pieces as small as / in. square may be produced success fully. While it is true that maximum strength demands minimum flow, the mechanical properties obtained exceed those of general-purpose phenolics. . .. Newest and most important development in the resin- board family is a diced or macerated type with an impa'ct strength of .38-.-15 ft.'-lb. energy to break by Izod test. Al though 3 to i times more resistant to mechanical shock than the general-purpose woodflour-filled phenolics, it can be pre- formed on both single stroke and rotary tabletting machines. Cut to pass U. S. Standard G mesh screen, it will feed through the hoppers of automatic molding presses as readily as gen eral-purpose materials. It provides all of the toughness, water resistance and other physicS>,characteristics for which standard types of resin boards and blanks long have been . known. Its surface appearance, when it is molded, is com parable to that obtained with regular phenolics. Tensile strength of standard molded test specimens of this new diced molding board ranges from -1500--5500 p.s.i. and flexural strength from T100-S500 p.s.i. Water absorption . after a standard 24-lir. A.S.T.M. test shows'a gain of only .4CK90 percent. Even after 5 hr. in boiling water, a 2-in. disk molded from this macerated board revealed a maximum gain of 1.9 percent. Dielectric strength at GD.cycles is 110-- 125 volts per mil (step method), and volume resistivity is 2-3 X 10' megohm centimeters. To secure maximum electrical . properties, however, the" material must be preheated. Both , dielectric strength and volume resistivity may be doubled by subjecting charges to 200 F. for 30 min. immediately prior . to molding. ' . t' . : .. ', . `' An important advantage of diced molding board.is its rela tively low bulk which, in common with that of other molding . board materials, permits its use in molds made originally for general-purpose phenolic, an aid in saving time and cost. Fabric-filled impact-resistant plastics, on the other hand, de mand extra deep molds to accommodate their greater bulk and more adequate heating of the platens for correct flow. Furthermore, the vastly increased molding pressures neces sary with fabric-filled phenolics call for molds of considerably stronger construction than those for woodflour-filled materials. Molding pressures for diced board, on the other hand, are relatively low--ranging from 5000-5800 p.s.i.' Molding tem peratures of 290-310 F. are adequate. .' - , Diced resin board is adaptable to a wide variety of appli cations where impact- and shock-resistance and high-speed fabrication are required, such as on the receivers and trans mitters of sound power telephones and for the. handles of large circuit breakers. {Phase turhto page 144) 4--First step in molding industrial gaggle frame of phenolic resin hoard is to cut one edge of hoLh strips to approximate contour of finished frame. 5--Strips ..are then dampened, coiled and dried--a preforming operation after which they are molded without further preparation. 6--Rings to hold tenses (below) are molded ^Rom flat stamped sections of-the phenolic hoard. ~!$ci~lfeadhand and lenses complete assembled giggles ten Injection 413. See 2S0 and fol. 43. Injection H. Horse and P. MacMlllln, See also Jnnd Jet Mold* : and follow* 1944 Encyclo`ion Molding p. 672. 676. niection Mold23 and follow- 1945 Encycloctfon .Molding se, p. 8CW-S04. InK f>y A R. njection Mott- R. Morse, p. lopedia, 1947, hlnes by A. R. *e also InjecMorse, p. S55- clopedia, 1948. bines, p. 1254 lotting, p. 924 btic Materials, on, lnc,, Wa* 48. Englnesrlnu lichigan. Mold lotting, tlniten drawings il & MnnufjtcIworth, New jjevUun Mott- : Hakelite ami e Corporation, Uy p. 99 ff.) of the Plask. (See espe-. c materials. Jeciors au* ress mater* apply eiecg,injectinto ally heated le accurately ,.. with only terinl'Cnres i production better than ul molding :c for Bulie- tog .%%'j is' pbsr-flaic"; "^veji5 in' the' face . 'of : - ^Spt - rising costs, to' design and build' a Standard Equipment: Motor, "timers, pyrometers, watev-cooliir, *2. nozzle? large capacity injection machine of ; and 7/16% wrenches. Machine to be ready for operation except for wiring approximately 24 ounce plastifylng of motor, piping of water-caoior, addition of hydraulic oil, and mold. SPB.Sets, January, 1949 , "* .*%/,, . .-% .'; 7*nI>-fnV PLASTICS IN PACKAGING DISCUSSED AT NEW YORK By ARTHUR M. MERRILL Thirty-four .members and guests of the New York Section attended a regular dinner meeting bn. December 14, at the Hotel Sheraton,' Speaker of the evening was Carl Cobbledick, packaging director of Egmont Arens Associates, who discussed "Plastics in Packaging." Plastics will become more widely accepted as a packaging material, Mr. Cobbledick said. Manufacturers' resistance to plastic packages has been based on their higher unit cost, but such resistance is not justified in view of the greater sales appeal of the plastic package. Although high- er unit costs prohibit use of plastics ^BT.,-` '..^HB ^ 'TT*. " \ ^ 'y + A. A .*- AH for everj' packaging application, the V; V following factors justify consideration of plastics for any specific pack- 0ff'A aging problem: (1) possibility of increasing sales by converting a plan- f- OR ''| ned purchase item into an impulse ' ^1 purchase item; (2) building demand A. M. Merrill and brand loyalty by plastic containers having re-use value; (3) merchandising the line with matched-set con tainers which stimulate the purchaser to buy the whole line in order to complete the set; and (4) prestige and novelty of plastic packages where such qualities help sales. Mr. Cobbledick illustrated his talk with samples of plastic packages used to merchandise different types of products, giving case histories of increased sales fol lowing introduction, of the plastic package. The speaker concluded by emphasizing that the plastic package is primarily a .merchandising aid and only secondarily a container. ., In the business session preceding the'talk, section president Arthur Nufor, Bakelitc Corp., announced the election of the following new directors: George Barron, Ideal Plastics Corp.; B. V- Walsh, Tech-Art Plastics Co.; . and Bruce Wessinger, Wes's Plastic Molds, Inc. Mr. Nufer also announced that the group will be the guests of the 'Newark Section at its next meeting,on January 12, at the Newark Athletic Club. "Selecting the Right Plastic Materials" will be the subject of this meeting, and spc3k- * ers will be Robert Burns, Bell Telephone Laboratories, `.and Emil Beekman, Army Signal Corps Laboratory, Ft. ' Monmouth. Table favors consisting of plastic puzzles with key chains wove distributed through the courtesy of Mr. Wessinger. , 1948 Notional Officers A welcome answer to insulation inolilems'in the electrical and electronic fields TAYLOR GRADE For switch stators and rotors, socket bases, condenser stators, insulating washers, and sim ilar applications ... Taylor Grade XXXP-I brings a new combination of insulation resist ance plus low power factor and .low dielectric ' constant, regardless ot. humility.' - After 24 hours in water, the power factor of this material shows a change ofless than 0.00X0 and dielectric constant changes less than 0.05 . .when tested at a frequency of 30s cycles./nau- ;-lation resistance", after four days' exposure; at 90 percent relative humidity and 35C, is 500,000 megohms. . .. .WriteforadditionaldataonGrade XXXP-1, and for fuli information on Taylor Vulcanised Fibre, Taylor Phenol Fibre, and Taylor Fabri cating Service. Count on Taylor for help in all problems involving Laminated Plastics. R. B. Bishop^ R. G. Dailey, j. H. OuBois, M. J. PetreHi SPE News, January, 19,49. ' . ?.*; ' : Tv'enly-snen Empirical Factors ini Injection >%. Machine Design ' BIBLIOGRAPHY (ConU -; '