In the early 1950’s, production of textiles in the United States was a vibrant, growing industry. Cotton was the primary fiber and demand was strong for both internally produced and purchased yarn. During this period, the industry enjoyed the attention of large chemical companies supplying products to textile manufacturing and finishing. It was in this environment that chemical companies actively pursued new applications for products for use in our industry.
A few large chemical companies serving the industry were involved in the manufacture of colloidal silica. The material was polymerized from water glass and acid to a spherical 20-50 millimicron diameter, 3-dimensional particle-stabilized to a pH of 9 or higher. Colloidal silica had found use in other industries but had not found utility in textiles. Marketing personnel were assigned to investigate this situation concentrating on properties obtained from the use of these materials in industries outside of textiles.
Improvements in tensile and elongation properties and yarn uniformity were outstanding. In addition, there were indications of reduced fiber loss in yarn formation.
The most obvious property exhibited by colloidal silica products was a frictional effect on surfaces. This prompted proposals to explore any benefit of colloidal silica on cotton fiber in yarn formation. At the time, large chemical companies supplying this sector of the industry had pilot-scale equipment to evaluate product performance on fiber. This provided a convenient path to develop relevant data for presentation to the industry.
Colloidal silica was sprayed on cotton fiber in the opening process and subsequently processed to yarn. Initial evaluations demonstrated no problems and extensive work was done in determining any effect on physical properties of the yarn produced. Improvements in tensile and elongation properties and yarn uniformity were outstanding. In addition, there were indications of reduced fiber loss in yarn formation. When colloidal silica treated yarn was put through the sizing process, warp stop levels were significantly reduced. Reduced fiber loss was also demonstrated in knitting. Application levels of colloidal silica on fiber were demonstrated to be in the range of < than 0.05- 0.08% active on fiber.
Armed with the data developed in laboratory pilot-scale equipment, sales technicians approached top management of operating yarn mills. Review of the data from the in-house pilot plants was sufficient to gain approval from mill management and colloidal silica trials initiated. All data from the pilot plant trials were confirmed and/or surpassed. Approvals for full production was put into place. The news of the success of the application of colloidal silica on fiber spread through the industry like wildfire. Colloidal silica on cotton fiber became the hot topic of the industry. Improvements in the total fabric formation process were validated by operating mills.
Improvements demonstrated were:
- Improved yarn physical properties
- Higher production yields
- Improved uniformity
- Reduced fiber and size shed in slashing
- Reduced warp stops in weaving
- Reduced shedding in the weave room
- Improved fabric quality
- Reduced fiber loss in knitting
- Improved knit fabric quality
A miracle additive had been introduced to improve textile manufacturing. Mills in the Southeastern USA quickly added colloidal silica into the yarn process.
After widespread use of colloidal silica had been adopted, mills found that machinery was being abraded at all points contacting the treated yarn. What had been ignored was the chemistry involved in stabilizing colloidal silica particles. Water in the product evaporates and leaves the process. Water evaporation packs colloidal particles closer together and pH stabilization is overwhelmed. Adjacent particles react to form an irreversible silica gel which continues to lose water to form a larger 3-dimensional inorganic particle. This particle is more commonly known as “sand”. Sand and textile machinery are not compatible. Abrasion of machine components was so efficient that the supply of replacement parts was exhausted. Mills stood idle. Use of colloidal silica was an economic disaster.
Unfortunately, the abrasive character of yarn bundles containing sand is the only feature of this failed project that has been remembered.
What has been overlooked from this very NEGATIVE experience has been the positive RESULTS achieved by increasing fiber cohesion (friction) within the yarn bundle. Improved fiber cohesion was provided remarkable gains in the manufacturing process. Unfortunately, this factor was overshadowed by the economic effects resulting from the abrasive character of the additive. The minor improvements in interfiber interaction in the yarn bundle have been demonstrated. This must be the objective without an abrasive additive.
The list of improvements provided in the list above is undoubtedly far from complete.