the size alone of the four dupont rayon plants gives some idea of the amount of specialized equipment and scientific craftsmanship needed to produce each year millions of pounds of fine rayon yarn yarns that are converted by leading textile mills into fabrics that make garments draperies and countless other fine articles found in the apparel and home furnishing departments of stores all over america actually these buildings are not factories but giant laboratories where skilled technicians follow specifications as high as those required in small experimental equipment within these walls work craftsmen to whom quality is a creed with the most modern equipment obtainable the interior of this dupont cellulose acetate rayon plant reveals a maze of intricate elaborate apparatus a labyrinth of containers mixers and other machinery linked by a network of pipes and valves to the layman a picturesque puzzle of queerlooking objects of every shape and size but in expert hands precision instruments that play major roles in the production of fine rayon yarn here nothing is left to chance constant control of every process is maintained by accurate devices that check and record every operating factor continual checking and testing throughout every step of the way is one big factor in dupont quality these laboratories dot every building examine the product of each important process make sure that nothing passes on for further treatment until it measures up to the highest standards set and rigidly maintained manufacture of viscose process rayon begins by steeping or soaking sheets of cellulose the first step in changing them into the spinning solution as we saw in the laboratory but while the principle is the same as with the glass beaker here the operation of steeping is carried out with exacting precision just the right amount of cellulose is placed in each compartment of the specially designed steeping press the sodium hydroxide solution is checked repeatedly to be sure it's just right and the sheets are allowed to soften and soak for a definite predetermined length of time before an automatically operated hydraulic ram begins to squeeze out some of the liquid its pressure is carefully governed so that the sheets will weigh just so much more wet than when dry even the weather in this room as in all other operations is manmade perfectly suited at all times to this particular process every factor that can affect the ultimate quality of the rayon is scientifically controlled to a fine degree the soft pulpy sheets pour through chutes to the floor below to be shredded into crumb these ingenious shredders gently crumble the sheets pulling them apart but not grinding them this machine also uniformly distributes the liquid remaining in the cellulose so that its action is the same on every crumb on the floor below the crumbs are poured into steel cabinetlike containers here are the crumbs are stored for aging under constant temperature every container bears an accurate record of its contents so it may be individually checked and controlled accurate scientific analysis determines when the right degree of aging has been reached at the correct stage the crumbs are released from storage and passed onto the next treatment which we remember is the addition of a liquid that changes them in color from white to orange in actual manufacture this process is carried out in huge rotating churns that are individually cooled to a precise temperature the snowwhite cellulose enters the barrellike interior of the churn which contains a pipe through which carbon disulfide is fed this liquid flows into the churn rotating at a definite rate of speed perfectly blending with the crumbs which gradually darken in color here again close control of every factor is absolutely necessary if our cellulose is to make fine rayon yarn the speed of the machinery is closely regulated exact timing is highly important for proper air conditioning the air is completely changed twenty two times every hour when the process is finished the cellulose xanthate or orangecolored crumbs are emptied from the churn notice how greatly they've increased in size and darkened in color an indication that they are now ready to be converted into the spinning solution in the laboratory we carried out this step by dissolving the crumbs in a solution of water and dilute sodium hydroxide contained in a glass beaker in the plant the spinning solution is made in huge cylindrical mixing tanks in which exact proportions of the ingredients are accurately maintained each lot produced is thoroughly analyzed by control laboratories located right in the plant all dupont rayon yarn enjoys uniform high quality mainly because its quality is never taken for granted it is constantly tested and proved throughout every step of its scientific manufacture to ensure the highest possible degree of uniformity in the spinning solution and in the finished yarn the various lots are blended together each huge blending tank is equipped with positive stirring blades that thoroughly mix the solution at this point the desired degree of luster in the finished yarn is also permanently fixed if brilliance is wanted the blended solution is used without further treatment the addition of a special pigment or certain types of oil changes the solution so that the yarn it produces will be dull in appearance the amount of delusterant added determines a final degree of dullness in the finished yarn after blending the spinning solution is allowed to ripen for an exact period of time to bring it to just the right condition for spinning unless it is properly aged the yarn it produces will suffer in quality so during its stay in the aging tanks the solution is regularly tested and checked in precisionbuilt presses all foreign matter is completely removed by thorough filtering not once but again and again throughout every stage of manufacturing the purity of the spinning solution is constantly safeguarded each piece of equipment is constructed of metals specially selected to resist corrosion and contamination of the products being handled the pipelines valves tanks mixers and other machines are designed and built to make the purest and finest spinning solution that science can produce the only kind of spinning solution that measures up to dupont's high rigid specifications before it is approved for spinning into top quality rayon yarn the actual spinning of the solution is one of the most fascinating operations in all industry we saw previously how a thin stream of the solution changes to a coarse strand of crude rayon when dropped into a hardening bath but the crude rayon formed in this way is entirely unsuited for making cloth as can be readily seen by comparing it with true rayon yarn to make this yarn requires a speciallydesigned precisionbuilt apparatus that is an outstanding example of modern machinery the liquid passes through still one more filter before it emerges from minute openings and a tiny nozzle called a spinneret how fine are these openings well generally they range in size from five thousandths to two thousands of an inch the thickness of a human hair each hole forms an individual filament and there may be any number up to four hundred or more of them in a single thimblelike spinneret notice how the liquid solution coagulates when the spinneret is lowered into the spinning bath and expert hands skillfully leads the yarn through a series of guides up and around a rotating glass wheel then down through a funnel into a whirling pot which collects it each threadlike filament forms immediately as a spinning solution leaves the holes in the spinneret the speed of the glass wheel largely determines the thickness of the yarn although this characteristic also depends upon the size and number of the spinneret holes and the amount of spinning solution forced through them per minute the collecting pot rotates at a very high speed from six to ten thousand revolutions per minute the rotation twists the filaments together and the yarn is distributed alternately from top to bottom so that it will lie properly against the wall of the pot to form a symmetrical cake when removed from the pot the cake of rayon consists of about twenty nine yarn by weight and seventy one spinning bath liquid which must be removed at predetermined intervals a cake of fine quality yarn is removed from each one of hundreds of spinning machines in other plants dupont acetate rayon is spun by yet another method the spinning solution made from cellulose acetate by a different chemical process known as the cellulose acetate process is forced through tiny holes in a spinneret located about fifteen feet above the level of the floor when the solution passes through a column of warm air one ingredient acetone evaporates and the liquid solidifies to form slender filaments of rayon by the time they reach the bottom of the warm air column the filaments are perfectly dry here they are collected and guided out of the column to a device that winds the yard on bobbins the acetate rayon yarn as it comes from the spinning machine is a finished product after twisting it is ready for weaving or knitting into fine fabrics each bobbin is numbered for easy positive identification so that every bit of yarn can be traced back to the machine that made it all dupont viscoseprocessed rayon is also carefully marked for reference before passing on through the finishing operations repeated thorough washing with pure warm water gradually softens and cleanses the yarn and gives it a smooth pleasant feel much of the moisture's removed in a speciallydesigned machine called a centrifugal extractor each cake is placed in an individual chamber which spins like a top at extremely high speed throwing off water without harming the yarn's fine texture and construction final drying is accomplished in automatic tunnel ovens through which the yarn travels on conveyors an exact degree of heat is maintained so that the yarn is dried gently and slowly now the yarn is ready for winding into the form desired by the fabric manufacturer the bobbins are so designed that at each stage of the processing strain is eliminated this permits proper tension in twisting coning tubing and skeining from raw material to finished product all dupont rayon whether made by the viscose process or the cellulose acetate process is continually checked by a rigid testing routine a continuous check on winding tension is made by periodically testing the tension of the running yarn specimen cones are regularly picked at random and rewound on a special machine that permits thorough inspection of the continuous yarn a highlytrained operator expertly examines the rayon as it passes in front of a black background that easily shows up any imperfections still other precisionbuilt testing appliances make sure that the physical qualities of samples of every lot measure up to dupont's high standards testing for yardage is accurately accomplished by a winding reel that turns it in exact degree of speed and measures the yarn precisely measured specimens of known length are then weighed on a sensitive gram scale to ensure the uniformity of the yarn the amount of stretch or elongation of any textile material as well as its tensile strength are both of considerable importance because they affect the service ability and wear of the fabrics made from it this testing device precisely records the amount of twist per inch in any given specimen of yarn the construction of practically every type of fabric greatly depends on how the yarn is twisted so uniform twisting is highly important inspection of the yarn as it passes over a strong light within a dark room is still another dupont control by the expert eyes of skilled operators any imperfection is immediately detected nothing but perfection gets by but with this organization careful surface inspection isn't enough by any means thorough microscopic examination tells the additional story of what's beneath the surface of the yarn crosssections of samples from every lab produced are prepared by making tiny wax candles with a strip of yarn forming the wick in the center the candle is then accurately cut into paperthin slices each of which contains a tiny crosssection of yarn for its core when a slice is placed in a powerful microscope and the focus properly adjusted the structure of each tiny filament is plainly revealed to the untrained eye such a picture means nothing but to the dupont expert the size shape and arrangement of every fiber tell a definite story about the quality of the yarn being tested notice a difference between lustrous rayon and dull rayon as revealed by the microscope the tiny specks of pigment in the sample on the right are embedded within each individual fiber a permanent part of its basic structure by scientific preparation and analysis of photo micro graphs of specimens of yarn from every lot produced the quality of the yarn is constantly safeguarded even when it has passed every other test all dupont rayon is carefully checked again before shipping to you the skein inspection may appear hurried and haphazard but with these girls years of training and knowing just what to look for have made hand and eye super sensitive to any possible defect no single cone skein or tube leaves any plant without this final thorough checkup from beginning to end one hard and fast policy dictates and controls the outcome of every operation test and check check and test every step of the way from the raw materials to the finished products nothing is taken for granted the result of each process is scientifically analyzed by accurate factfinding equipment in the hands of experienced capable technicians it takes plenty of time skill painstaking care and effort to follow such a procedure in largescale production but that's the only way fine rayon is made yarns that make possible fabrics that lend new beauty and attractiveness to clothing and home furnishing countless articles of distinction to be found in fine shops and department stores from coast to coast smart dresses for every occasion for woman miss or child made of every conceivable type of material for lingerie and negligees there are satins french crepes flat crepes taffetas and knitted fabrics of every type fine menswear too gains variety and good looks through fabrics made of dupont rayon yarn underwear ties sweaters shirts pajamas hose slacks and tropical suitings for sportswear leading curtain departments everywhere feature rayon marquisettes voiles ninons and plain and novelty weaves draperies and bedspreads rich brocades brocatelles jacquards repps twills moirees satins damasks and plain weaves and for fine furniture dupont rayon provide outstanding upholstery fabrics for one thousand and one essential articles of daily use dupont rayon yarns insure beauty and long life backed by the symbol of rayon quality pure assurance that the yarns used are made to the highest standards of quality precision and honest careful craftsmanship rayon yarns that take a merited place beside every other important development that has added beauty luxury ease and comfort to our daily life rayon yarns by dupont