Pen Astrogum

Description of Product

Pen Astrogum form highly stable starch pastes when cooked in conventional systems in the size room preparation, whether in an open cooking machine or under high shear (turbo) system.

Under these systems, the product should reach boil and then is ready for use. In an autoclave, the material is ready for use when the temperature reaches 100-105 degrees.

Properties of Product

Appearance White to light yellow granules
Solubility Readily Soluble in water
Ionic Charter 70% Anionic
PH 7.5
Moisture 10-12.5%
Viscosity Solids 14% 500-1000 (RVA)


Pen Astrogum is compatible with all standard size formula polymers currently in use. It increases viscosity stability and reduces the size formulation tendency to gel upon cooling. Pen Astrogum can be used with all grades of PVOH, CMC’s of different purity, and all unmodified and modified starches, irrespective of modification method. It is compatible with all type of solid or liquid waxes.


Pen Astrogum can be used on all types of spun yarns and their combinations. Pen Astrogum provides superior rheology to size formulas, providing better encapsulation on those applications where squeeze roll pressures exceed 1000 kilos.

Pen Astrogum provides better viscosity stability to the size formula when used high speed in sizing machines with a better viscosity stability, size formulations incorporating spar provide constant wet pick up, a perquisite for high weaving efficiencies in shuttle less looms.

Pen Astrogum can be used to replace all or part of the binders in the formulation, therefore reducing costs, better viscosity stability, superior adhesion, and better encapsulation are some of the benefits provided with the use of spar. All translates into better fabric quality and higher weaving efficiencies.

Pen Astrogum can be added at any time during the cooking cycle. There is no need for special cooking instructions.


Pen Astrogum is water soluble. Sizing formulations containing Pen Astrogum still have to be desized according to the primary ingredients in the formula.

The Pen Astrogum can be desized without enzymes. We recommend as follows:

  • Run desize in full width form, not rope form.
  • Run water in desize range as hot as possible. We recommend water temperature of 90°C or greater.
  • We recommend counter current water flow with an overflow with as fast a water flow as possible to wash off the residual size.
  • We recommend a non ionic surfactant in the first box to assist in the wet out of the fabric.
  • If using PVA in then formula along with Astrogum, we do not recommend the use of caustic soda or soda ash as this may set up any PVA on the fabric.
  • We recommend as many wash boxes as possible.

Safety and Handling

Pen Astrogum is non toxic. Due to its mild alkalinity, it might be slightly irritating to the skin or eyes.


Pen Astrogum is packaged in 25 kilo, multiwall paper bags with a polyethylene inner liner. It is recommended that open bags be resealed or used in a short time as the product is hygroscopic, absorbs humidity, and caking might occur. Caking does not affect the quality of the product, only its appearance.

What is Pen Astrogum

Chemically, Pen Astrogum can be described as hydroxyethyl ether derivatives of corn starch. The hydroxyethyl groups are attached directly to the starch molecule by strong ether linkages. As a result, the new chemical compound, while having the physical form and appearance of the original raw corn starch, has markedly changed properties which adapt it to a myriad of uses.

The process for the manufacture of the Pen Astrogum is covered by U.S. Patents 2,516,632-3-4.

What are the Properties of Pen Astrogum?

The properties of Pen Astrogum can best be described by explaining how and why they differ from those of the familiar corn starch.

Starch may be classified chemically as a polysaccharide or polyalcohol, with the molecules consisting of long chains of anhydroglucose or simple sugar units. These chains can either be straight or branched with the proportion of each, as well as the chain lengths, varying with the source or type of starch.

As each anhydro-glucose unit in the starch molecule contains three hydroxyl groups, the number of these groups on the starch chain is considerable and they are responsible for many of the properties possessed by starch. One of the prominent characteristics of these hydroxyl groups is the attractive force they have for each other or for water or other hydrophilic materials. This force is variously described as hydrogen bonding, inter-molecular association, ect.

The attraction these hydroxyl groups have for water increases when slurry of raw starch in water is heated so that at the gelatinization temperature it becomes greater than the attraction the molecules have for each other and the starch is said to paste, to hydrate, or to disperse. However, even in the cooked or dispersed state, the associative tendency of the starch molecules for each other is apparent and is believed to be responsible for some of the undesirable changes evident when a cooked starch paste or sol is cooled, aged, or dried.

The tendency of a cooked corn starch paste to thicken or gel on cooling or aging is due to the tendency of the dispersed or hydrated molecules to associate with each other. The result is a loosely cross-linked molecular network of still hydrated starch having an increased viscosity, or even setting up to a stiff gel. This phenomenon is often referred to as “set back” of the starch.

In some instances this association between starch molecules progresses to the point where it becomes irreversible under normal conditions and some of the starch may actually precipitate from solution. Frequently, as when a starch paste or film is dried, this irreversible association between molecules takes place and an insoluble mass is formed which does not readily rewet or redisperse back to the previous hydrated sol form. The term retrogradation is usually applied to this irreversible molecular association.

The substitution in the starch molecule of any chemical groups which will modify or overcome some of the properties of the hydroxyl groups may greatly change the properties possessed by the starch itself. This has, indeed, been demonstrated in the case of Pen Astrogum. The replacement of a relatively small proportion of the hydroxyl groups in the starch molecules by hydroxyethyl ether groups can be accomplished while the starch is in granular form. This results in a product which has markedly different, and for many uses, vastly improved properties.

The presence of these hydroxyethyl ether groups on the starch molecule is very effective in reducing the associative forces between molecules, giving the following improved qualities:

  • Lowered Gelatinization Temperature – The Pen Astrogum swells and gelatinizes in water at temperature of from 10° to 30° F lower than do corresponding unsubstituted corn starches.
  • Improved Viscosity Stability During Cooking – Pen Astrogum granules hydrate more rapidly in the cooking process and, consequently, more quickly reach homogeneous, viscosity-stable conditions.
  • Reduced Gelling Tendency, Improved Viscosity - Stability on Cooling or Aging – Cooked pastes of Pen Astrogum show little or no tendency to form the usual stiff gels on aging. Viscosity is unusually stable over long periods of holding.
  • Decreased Retrogradation Tendency – Cooked pastes of Pen Astrogum have a greatly reduced tendency to retrograde or form irreversible crystalline precipitates in solution. When pastes are quick-frozen and thawed, they return much to their original condition, rather than the form the insoluble starch “sponge” as do unsubstituted corn starches.
  • Increased Film Solubility – Pen Astrogum films are easily susceptible to redispersion on rewetting with water.
The advantages of Pen Astrogum have been demonstrated by its extensive use in all types of mills and have been responsible for their wide-spread acceptance by the textile industry.

Warp Sizing

The superior filming properties of Pen Astrogum enables it to coat fine combed yarns with a tough, elastic sheath or film which imparts maximum resistance to the abrasive action of the looms on high count broadcloth constructions. The non-congealing property of Pen Astrogum virtually eliminates the problem of hard size around the edges of the size box and roll marks on the warp when the slasher is stopped for doffing of the warp beam, etc. In these relatively viscous combed yarn size solutions the superior size box stability of the Pen Astrogum contributes to a more uniform addition of size to the warps. The heavier Pen Astrogum has proven particularly effective in providing maximum weaving protection to combed yarn. They are usually prepared with suitable adjuncts and used in concentrations from 0.8 to 1.0 pounds per finished gallon.

Sizing of 100% Hydrophobic Fibers (Acrylic, Modacrylic, Nylon, Olefin, Polyester)

The properties of these synthetic hydrophobic fibers are sufficiently similar to create common sizing problems on spun singles yarn. The solution to these problems in each case involves:

  • The application of sufficient volume of aqueous size to provide 12 to 18% actual dry added size weight for 100% synthetic fiber yarns, or to provide 8 to 15% added weight for blends of synthetic fibers with natural and man-made cellulosic fibers.
  • The provision of a dried size film of such a nature that it will not separate from the highly elastic yarn when it is stressed or stretched during weaving.
  • The provision of a size film which will afford adequate protection to the yarn so that a high level of efficiency can be maintained in the weaving operation
While the Pen Astrogum films adhere to the hydro-phobic fibers better than do those of conventional starches, experience has shown that the addition of certain adjuncts to Pen Astrogum sizing improves the adhesion, extensibility and lubrication of the films on these fibers. The inclusion of polyvinyl alcohol, CMC, or neutral acrylic resin in quantities up to 25% of the Pen Astrogum weight with up to 5.0% non-sulfonated 130° - 160° F melting point wax on the Pen Astrogum basis provides practical and economical Pen Astrogum sizes for these yarns.

As these size fibers are relatively non-absorbent, it is necessary that a high solids and high viscosity size be used to bring about the retention of 12 to 18% size solids on the yarn, which is considered optimum for the majority of the hydrophobic fiber spun yarns. The Pen Astrogum 260, 280, 360 and 380, in concentrations ranging from 1.25 to 2.5 pounds per finished gallon, provide the required amount of dry size in and on the yarn to protect it against the abrasive action of the loom and to eliminate the clinging of protruding fibers from adjacent ends in the shedding motion.

Worsted Sizing

The non-congealing properties of Pen Astrogum make it particularly attractive in the sizing of worsted fibers where it is common to operate at temperatures as low as 160° F, to prevent damage to the wool fiber. The Pen Astrogum films adequately bond the protruding wool fibers to the body of the yarn and provide excellent weaving protection.

Here again the choice of the formulation used depends on the fabric construction as well as on slasher arrangement. A double application of size with partial drying between applications normally requires a lesser concentration of Pen Astrogum than does a single application or a double application without intermediate drying.

Most worsted singles yarn is slashed with a size box temperature of from 140° to 190° F, and requires a free-flowing high concentration size mixture which will provide the 15 to 24% added weight necessary for efficient weaving.

A double size application with intermediate drying can be effectively done with Pen Astrogum 260 in concentrations ranging from 1.5 to 1.75 pounds per finished gallon, while a single size application or the double application without intermediate drying requires the thinner Pen Astrogum 280 in concentrations of 2.0 pounds per gallon or higher. Pen Astrogum 270, with viscosity midway between 260 and 280, may be used in suitable formulations with either the single or the double size application, with or without intermediate drying.

Usual practice is to add 1.5 to 3.0% nonsulfonated 130° to 160° F, melting point wax to the above worsted sizing formulations as a softener.

Sizing of Blends of Hydrophobic and Other Fibers

Pen Astrogum provides an effective size for blends of the hydrophobic fibers with either natural fibers or with other synthetics. In sizing warp yarns composed of these blends, the composition of the size usually approaches that of a size which will be satisfactory for the component present in the larger proportion.

In blends containing up to 50% hydrophobic fibers, the Pen Astrogum, when used with a nonsulfonated 130° to 160° F melting point wax as a softener produce a high rate of weaving efficiency. Blends containing more than 50% hydrophobic fibers are progressively treated as though their composition were 100% hydrophobic fibers and the formulation used is modified to include increasing percentages of sizing adjuncts.

Each of the multitudes of blends and the variety of constructions requires a size with a viscosity concentration relationship which will give the added weight necessary to protect the specific yarn during weaving. This makes necessary sizing materials in a wide range of viscosities to satisfy the many requirements and such a need is adequately met by the Pen Astrogum 200 through 290, and Pen Astrogum 300 through 380 series of products.

In the preparation of such sizing formulations the Pen Astrogum should be slurried in water along with the desired adjuncts for 10 to 15 minutes to insure completed dispersion prior to cooking. The amount of water used is that which with the condensate from the open cooking steam will give the desired finished volume. The mixture is brought to a boil in 15 to 30 minutes and then held at a boil for an additional 45 minutes before use.

The non-congealing properties of both the Pen Astrogum 200 and 300 series of product sizes permit slasher operation at any desired temperature between 140 and 200 F, although a size box temperature of 180 to 200 F is usual. The more highly ethylated Pen Astrogum of the 300 series is recommended for applications requiring the ultimate in low temperature sizing and minimal processing in desizing.

Low Added Weight Sizing with Pen Astrogum

Intermediate size levels between conventional and the “low add-on” concept of the carboxymethyl cellulose and polyvinyl alcohol sizings can be obtained with higher viscosity Pen Astrogum of the 200 and 300 series of products used separately and in combination with CMC or PVA. The required level of added weight with the Pen Astrogum without adjuncts is somewhat higher than that normally obtained with 100% CMC or PVA sizings; however, Pen Astrogum in 65/35 and 50/50 ratios with CMC or PVA provide low “add-ons” comparable to that obtained with 100% CMC or PVA sizings.

Pen Astrogum of the 300 series is recommended for the combination sizings with CMC or PVA due to the higher degree of ethylation and resultant easier desizing properties. The choice of fluidity of Pen Astrogum is dependent on the ratio of Pen Astrogum to CMC or PVA and the formula concentration required to provide sufficient sizing for optimum weaving protection of the fiber blend and fabric construction being processed.

Textile Printing

The viscosity stability, minimized congealing tendency, and ease of removal of the Pen Astrogum make them eminently suitable for printing paste when their slightly stringy paste character is shortened by suitable adjuncts. When so formulated they provide sharp prints with unusually good color yield. Many conventional printing pastes contain about 12% solids and the paste viscosity necessary for good results may usually be obtained by using this concentration of Pen Astrogum 240. Pen Astrogum 200 in an 8% concentration is recommended in printing pastes in which very low solids are desired with maximum color yield. This product also provides an excellent plisse printing gum when used in a 6% concentration with 30% caustic soda.

Textile Finishing

The Pen Astrogum contains a high degree of hydroxyethyl ether substitution and is extensively used in textile finishing to provide superior finishes. Their improved flow and filming properties and their high reactivity with both melamine and urea-formaldehyde resins has made possible the development of an entirely new series of textile finishes.





Product % solids tested           10% pH
  6 8 10 12 14 16    
Penflex CS9010-LV 44 60 69 119 165      
Penflex CS9010-M 54 77 97 164 345      
Penflex CS9010-HV 59 79 217 436 744      
PVA 205   15 25 35        
SS-200 33 63 110 180 340 590   5.6
PVA 613 / PVA 418 44 58 112 215 410      
Tapioca TX-TS 29 36 41 68 84      
Tapioca TX-7100 84 190 328          
Protex 169 204 345 1130 1580      
Pen Astro Gum 62 112 120 160 224 390   6.3
Quicksolan SPR 62 72 82 96 105 130   10.4
Penflex CS9010-EHV 75 156 355 656 880      
Penfilm 40 51 64 88 100 125 157   7.5
All tests were run at 90C (194F)
Brookfield run with #2 Spindle @ 50 rpm







Temperature solution (ºC) 80 80 80
VISC. (CPS) (SP 1,50 RPM) (Brookfield DV-E) 24 27 18.5
VISCOCUP (11 SEC. H2O) 14 15 15.2
pH at 70ºC  (Universal Indikator) 10-11 6-7 6-7
Rf (%) 7.8 7.8 9
Appearance  8 % Solution40ºC) Clear Yellowish Liquid Opague  White Paste Translucent Liquid
Cooking condition 95ºC X 30'      
Viscosity measured at 80ºC      
Concentration 8% solution      
Viscosity measured without subjecting to high shear.