In order to provide the American textile industry with the specialized know-how and research capabilities of the German chemical
industry, Sou-Tex Chemical Company was founded in 1953 by Harry M. (Wally) Thompson, Jr. in Mount Holly, North Carolina.  He had
flown to Frankfurt in 1952 to inquire directly with Cassella Farbwerke Mainkur AG about the possibility of manufacturing in the US their
line of Cassofix fixing agents for direct dyes. Licenses for the manufacture and sale of chemical auxiliaries dyeing and finishing were
obtained.

The operation started with the manufacture and marketing of Cassofix FFL.  The response to this product was excellent, with sales of
$10,000 the first year.  Cassofix FRND and Cassofix AC were added to the line.  In a few years, the products became a symbol of
quality and performance throughout the industry. Encouraged by this success, Cassella entered into an agreement with Sou-Tex
pledging complete technical support and in 1958 Sou-Tex became a subsidiary of Cassella. Many other original products such as the
Cassopars and Casservols were subsequently introduced, resulting in a substantial  auxiliary chemical business.

The favorable reaction of the American textile industry to the Sou-Tex philosophy led to the decision in 1960 to enter dyestuff
manufacturing.  This would give customers the opportunity of taking advantage of the dyestuff research which was the basis for over   
100 years of the success of Cassella world-wide.  

Cassella had an excellent line of Hydron vat dyes and Hydrosol sulfur dyes and agreed to teach Thompson the manufacturing details.  
After a short internship, Thompson returned to Mount Holly with the first baking drums.  Sulfur and other raw materials were charged to
the cylindrical gas-fired drums and rotated for hours.  These drums were about five feet in diameter and eight feet long.  Thousand
pound batches were normal.  Metal “stars”, placed in the drums during synthesis, ensured the dye would be a powder after the long
process was complete.

Later results of the extensive research work of Cassella included the Polyestren Dyes, a unique development in the field of vat dyes.  
This range of colors had brightness, ease of application, obtainable fabric appearance and above all the stability to withstand severe
testing conditions for sublimation, wash-and light-fastness.

The development and subsequent US manufacture of water-soluble sulfur dyes such as the Hydrosol and Cassulfon brands,
combined advantages such as ease of application and oxidation, better fabric appearance, and higher penetration.

A staff of hundreds of chemists and application technicians was engaged at Cassella to find new avenues and ideas in the dyestuff
field and improve upon existing ones. The Sou-Tex technical staff, both in the field as well as laboratory, was engaged in constant
application development and modification of product ideas to meet the requirements of the American textile industry.

Production, which had started in 1953 with only 13,000 pounds, grew to over 6.5 million pounds of auxiliaries and dyes in 1966.  The
facility, located on the Catawba River in Mount Holly, North Carolina, consisted of 65,000 sq. ft. of laboratory, manufacturing and office
space.   In 1970 negotiations with American Cyanamid and Hoechst resulted in the sale of Sou-Tex to Hoechst.  The product line at
that time is described below:

Polyestren Dyestuffs- Vat dyestuffs for dyeing polyester and polyester/cellulose mixed fabrics. They distinguished themselves by very
good fastness to light, rubbing, and sublimation as well as excellent fastness to washing and chlorine.

Solidokoll- Synthetic thickening agent and anti-migration agent of low viscosity for the dyeing of Polyester and Polyester/Cotton blends
which appreciably increased the color yield.

Cassofix- Range of fixing agents to improve any kind of wet fastness property on cellulosic fibers with a minimum effect on light
fastness and negligible shade change.

Cassopar- Non-ionic leveling auxiliaries for vat and sulfur dyestuffs with absolutely no retarding effect. Increased migration ability and
solubility of leuco compounds.

Casservol- An ionic padding assistant for natural and regenerated cellulosic materials and an effective diffuser for Polyester/ Cotton
blends.

Wally Thompson remained with Sou-Tex until 1973.  Spartan Mills and the Cherokee Finishing plant, which used large quantities of
Hoechst vat dyes in the rotary screen print works, wanted to investigate a new water-based thickening agent to replace solvent-vased
thickeners.  Could Thompson develop and manufacture the thickening agents?  He left Sou-Tex and founded Catawba Chemicals in
partnership with Spartan Mills.   Thompson worked closely with Joseph van Pragh, general manager at Cherokee, and developed a
successful product which was introduced at other printing operations such as the Burlington plant in Brookneal, Virginia.

Business increased and in1975 Catawba Chemicals purchased the Charlotte Chemical labs of the Stahley Chemical division of
Guilford Mills.  The name was changed to Catawba-Charlab, Inc.  In 1982 Thompson approached CHT, an affiliate of Chemishe Fabrik
Teubingen of Teubingen, Germany, signing a license to produce their line of textile auxiliaries.  AZS of Atlanta, which produced binders,
was acquired in 1983.  In 1998, Wally Thompson sold his shares to his son Harry III and to CHT.  Spartan Mills sold their interest in the
business in 2001.
Sou-Tex Chemical Company Brochure ca. 1967.  
Click to Enlarge.
Cassella Dye Works in Frankfurt, Germany 1967
Cassella Dyestuff Reactors
Research Laboratory
Dye Laboratory
Sou-Tex Offices, Mt. Holly, North Carolina
References:

1)  Sou-Tex Chemical Company brochure, ca. 1967
2)  Telephone interview of Harry M. Thompson, Jr. by Gary N. Mock, March 30, 2001

ColorantsHistory.Org thanks Gary N. Mock for contributing the reference material for this history.
Sou-Tex Chemical Company
Mount Holly, North Carolina
ColorantsHistory.Org