Better performance

15th of September 2010
Better performance
Better performance

Wim van Druren of Interpolymer, a global producer of polymers and wax dispersions for carpet care applications, writes for ECJ about the structure, cleaning and care of carpeted floors.

Textile flooring that fully covers the smooth floor of a room is referred to as carpet. All around the world it is greatly appreciated and in Germany it is the most commonly used floor covering. Its advantageous properties surely contribute to this fact. After all it is warm, safe, sound absorbent and contributes to the appealing design of a room.

The use of pigment-coloured fibres guarantees proper hygiene when suitable cleaning and care procedures are applied. After heavy soiling and frequent walking so-called deep cleaning is applied to the floor by using either spray extraction or shampoo. However, special cleaning formulations must be employed in order to reach an ideal cleaning performance with effective anti-soiling protection. Special polymer-additives lastingly improve the cleaning performance of cleaning formulas. The carpet also dries properly after the cleaning process. A brittle, crystalline residue forms a protective film on the carpet fibre which has a positive effect on the redeposition of dirt. This residue protects the carpet from re-soiling and dirt can be easily removed by vacuum cleaning.

Manufacture of carpets

Of the many different manufacturing processes such as weaving, tapestry and needling, adhesive pile fabric production and tufting, the latter method is the most frequently employed on a global scale. Tufting has its origin in the USA. This laborious manual work was done during the years of the early settlers by tufting (ie, inserting) a soft pile thread into a carrier material with a needle. The change from this manual method to an automatic processing led to the production of tufted carpets.

Tufting is based on the sewing-machine principle with a number of needles aligned next to each other and simultaneously inserting so called pile yarns into a carrier material (without warp thread) across the whole width of the material. After insertion to the carrier material loopers hold the yarn as the needle is withdrawn forming a loop. These loops (pile naps) form the top (pile layer) of the tufted material, which is the usable side (pile) of the carpet.

In this way, textile flooring with a pile that consists of loops is created and therefore called a loop pile carpet. If the looper has a cutting attachment the loop is cut as the looper is withdrawn and that would form a cut pile carpet, also called velour. A velour top can also be created by shearing the pile top.

During another process the bottom loops of the pile yarn, ie, in the back are bonded to a primary backing to provide sufficient stress resistance to the tufting carpet.

In addition to the primary backing generally a secondary backing, for instance a foam backing, is affixed. The carrier material consists of polypropylene woven fabric or fleece, polyester fabric or fleece or jute fabric. For fibre fabrics used as pile yarns natural fibres or chemical fibres can be employed. The most important natural fibre is new wool. Chemical fibres are spin fibre yarns and filament yarns based on:  Polyamid (PA), Polyester (PES), Polyacryl (PAN), Polypropylene (PP)

Carpet cleaning includes different types of cleaning. First of all, regular cleaning by vacuuming or brushing, where dust and dirt particles are daily removed; secondly, intermediate cleaning; and thirdly, deep cleaning. Intermediate cleaning removes slight soiling and easy stains on individual spots of the carpet. Carpet powder or dry foam is applied and worked into the carpet pile by brushing or shampooing, and after some reaction time it can be removed again by subsequent vacuum application, while at the same time removing dirt particles.

Deep cleaning. Once the carpet is heavily soiled and has been frequently walked on deep cleaning is employed by applying either a spray extraction or shampoo. This cleaning process always leads to some degree of wetness on the carpet. Therefore, textile floorings with jute fabric as carrier materials or with non water-resistant colours, or floorings that are fully covered with dispersion adhesives that dissolve through re-emulsification are not suitable for cleaning with spray extraction or shampoo.

Carpets with the following features are unproblematic to clean:

• Velour or loop pile layer.
• Polyamide and polyester fibre material.
• Carrier material without jute or cotton fractions.
• With strong foam backing.
• Fully covered by adhesive.

Both cleaning agents used for carpet shampooing and spray extraction require special products. This results from the functionality of these cleaning processes. With spray extraction the cleaning formulation in the tank is sprayed onto the carpet pile with a cleaning lance. This process wets the flooring from pile to carrier material. Simultaneously the used solution with the dispersed dirt is vacuumed by means of a lance above the spray nozzle that has an intake opening to free embedded soiling and particles deep down.

With heavy soiling the floor is first sprayed and after some reaction time vacuum cleaned. The spray extraction detergent must have an excellent wetting and dirt dispersion function. If the carpet is treated with shampoo it is first applied to the carpet with a single disc machine and worked into it by a rotating disc brush which is attached to the pad holder. After that the detergent is worked into the floor with spiral like movements followed by immediate subsequent water vacuuming.

Anti-re-soiling - Specific properties of a carpet cleaner can be recognised by considering the residue that adheres to the pile fibres. A primarily factor is thus not the remaining dampness but rather the surfactant containing residue of the detergent covering the surface of the carpet fibres. Due to this residue the fibre surface remains hygroscopic and tacky so that dirt particles are attracted very easily and therefore re-soiling on the pile surface when walked on
is enhanced.

This also explains why often it can be observed that certain parts of a carpet are soiled more heavily than others when such were previously only spot-cleaned with a surfactant based cleaner without polymeric additives (eg, washing-up liquid). Since these spots are especially prone to resoiling due to the remaining tacky surfactant residue, they often turn into dark stains.
The invention of special polymers that are added to the carpet detergent a brittle, crystalline residue forms on the fibres after the cleaning process which then creates a non tacky, dry fibre surface. The protective film that is thus formed delays re-soiling and facilitates subsequent soil removal. Despite this protective film, however, the grip of the fibres is not affected in any way but remains soft and velvety.

Residue testing - A simple and practical suitability test for users is to put some carpet cleaner into a bowl and let it dry at room temperature. A dry, brittle and non tacky residue should remain. The residue that forms with a special carpet care polymer additive (SYNTRAN® 4020, 4125 or 4180) forms a brittle, crystalline residue upon drying. The formation of a tacky residue results without any polymer additive. The hard, crystalline film on the fibres, that is, on the pile surface effectively protects the fibres from resoiling. This can be proven by testing the resoiling behaviour.

Soiling test

For this test carpet specimens (90cm x 30 cm) are divided up into three pieces of equal size. The first specimen is wet-cleaned by a carpet cleaner with a polymeric additive and the second with the same cleaner but without a polymeric additive. The third specimen is only treated with water as a blind test.

The specimen is mounted onto the inside of a cylindrical drum (Interpolymer Accelerated Soiling Drum). Then six grams of standard soil (carpet soil I, Type 09W, wfk Test fabric GmbH) and several plastic balls (D = 1 cm) are added and brought to a spin at a speed of 14 turns per minute for two periods of 30 minutes each and with a change in spinning direction after the first 30 minutes.

After the soiling process the specimen is taken out and vacuum cleaned and the degree of soiling measured using an X-Rite Spectrophotometer to calculate the so called L-value. An L-value 100 of a strictly white surface corresponds to the L-value 0 of a surface coloured in black. This cycle of soiling and subsequent vacuum cleaning is repeated five times in a row.

The soiling degree increases with each cycle. However, the carpet specimen that was pre-cleaned by the polymeric detergent continued to have a comparatively brighter surface, ie, it resoiled less. As expected, the specimen that was only wetted with water showed the highest degree of soiling.
The efficiency of carpet care products can lastingly be improved by adding special polymers (SYNTRAN® 4020, 4125 and 4180) since these ensure that once the cleaning process is finished there is no tacky residue upon drying. The formation of a brittle protective film on the fibre surface reduces the re-deposition of dirt and aids subsequent soil removal.

With every vacuum cleaning application the brittle protective film partially wears off and is gradually removed with dust and dirt particles. It leads to an easy removal of dirt and to a constantly clean fibre surface after every cleaning process.

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