Is Cellulosic Browning a Thing of the Past?

February 18, 2011
/ Print / Reprints /
ShareMore
/ Text Size+
linen-pile hand-knotted rug


Cellulosic browning on wall-to-wall carpet is, for all practical purposes, a thing of the past. That’s because most broadloom carpet today is made with all-synthetic materials: synthetic pile yarns, synthetic backing materials, even synthetic latex. The point is that, without any cellulose present, there is no chance of browning forming.

prespraying half w/reducer-shampoo

However, with area rugs, that’s a totally different story.

A tan-to-brown generalized staining on rugs – particularly hand-tufted rugs – can be caused by cellulosic browning. Cellulose is the basic building block of plant life. In rugs, cellulose can be found in pile yarns (e.g., jute, cotton, linen, sisal, coir, abaca), in foundation yarns (typically cotton or jute), in fringe (typically cotton), or in secondary backing fabrics (typically cotton).

brush agitation

In the case of hand-tufted rugs, cotton is used as the base fabric into which pile yarns are hand tufted, and the secondary backing is made of 100% cotton yarns. Even machine-woven 100% olefin pile rugs can exhibit browning if they have cotton warp or jute weft yarns in the foundation.

hot water extraction (acid rinse)

Factors that contribute to cellulosic browning include:
  • a cellulosic material – e.g. cotton, jute, etc.
  • old or degraded cellulose
  • water or overwetting
  • alkaline cleaning solutions, especially if hot, and
  • prolonged drying


soil and browning removed

Browning arises when a rug’s cellulosic materials become wet during cleaning, or are made wet during unexpected releases of excess water (i.e., water damage). In cellulosic materials, the cells of cellulose are bound by a red-brown sugar-like substance called beta-glucose, or more simply, lignin. Lignin is soluble in water, especially hot alkaline water.

When lignin is dissolved in water, during drying, the water migrates or “wicks” to the surface of pile yarns. There the water changes from a liquid to a vapor during evaporation; however, the lignin, which does not evaporate, remains on yarn tips, eventually causing a tan or brown stain.

comparative difference

Cellulosic browning is corrected by cleaning using a reducing or a mild oxidizing bleach (i.e., hydrogen peroxide but never chlorine bleach, since that removes color and dissolves protein fiber). Reducers are preferred, since they are less apt to remove color and they have no long-term deleterious effect on natural fibers such as wool or cotton (see photos 1-6).

Once removed, browning is prevented from returning by leaving fibers in an acid state (i.e., pH 3-5) during rinsing, which is the normal pH range for processed wool fiber.

fringe browning

When browning occurs on machine-woven rugs with olefin pile, it’s simply a matter of giving the rug a light rinse, followed by forced drying.

Browning correction on cotton fringe (photo 7), which was covered in a previous ICS article, is removed by applying a reducing solution, followed by hot water rinsing using an approved acid rinse (photo 8).

browning corrected w/reducer

To prevent cellulosic browning during future cleaning of any rug, especially hand-tufted rugs, they should be cleaned by an IICRC-Certified and experienced technician. Certified technicians who have achieved the Carpet Cleaning Technician (CCT) and Rug Cleaning Technician (RCT) designations can be located at www.certifiedcleaners.org.

Did you enjoy this article? Click here to subscribe to i Cleaning Specialist Magazine.

Recent Articles by Jeff Bishop

You must login or register in order to post a comment.

Multimedia

Videos

Image Galleries

The 2014 Experience Conference and Exhibition

A look in photos at the 2014 Experience Conference and Exhibition, which was held from April 24-26 at the Embassy Suites Convention Center and Spa in Frisco, Texas.

1/27/15 2:00 pm EST

Grow Your Business and Improve Operations with New Payment Technology

Attend this free webinar to learn how new developments in payment technology can help you close more jobs, increase upselling opportunities and improve operations.

Podcasts

The winter slow season is a great time to pursue commercial cleaning accounts and stay busy. John "the Hitman" Braun solicited questions from thousands of cleaners across the country regarding their questions on commercial cleaning accounts and answers them in this episode of the show.
More Podcasts

ICS Cleaning Specialist Magazine

CoverImage

2014 Nov/Dec

The Nov/Dec ICS features content on how to get better meter readings, a roundtable on truckmount development, neighborhood marketing and more. Also included is the annual Buyer’s Guide and Directory.

Table Of Contents Subscribe

Janitorial Work

In addition to residential and commercial carpet cleaning, do you do any janitorial work on the side?
View Results Poll Archive

THE ICS STORE

FinalCover.gif
The Carpet Cleaner's Book of Unlimited Success! (ebook)

Don’t worry about the recession or about your competition.  Now you can be the owner of over 400 ways for carpet cleaning professionals to make more money and get more jobs!

More Products

ICS DIRECTORY AND BUYING GUIDE

Director_Buyer.jpgThe premier resource and reference guide for the cleaning and restoration industries.

Click here to view

STAY CONNECTED

facebook_40.png twitter_40px.png youtube_40px.pngcrc logo

TRUCKMOUNT EQUIPMENT AND ACCESSORIES GUIDE

Truckmount.jpgEquipment listings and specifications from the leading industry manufacturers.

Click here to view