Fabric (woven – knitted – or nonwoven textile or cloth – etc.) – Coated or impregnated woven – knit – or nonwoven fabric which... – Coating or impregnation is water absorbency-increasing or...
Reexamination Certificate
1999-05-25
2001-01-23
Cole, Elizabeth M. (Department: 1771)
Fabric (woven, knitted, or nonwoven textile or cloth, etc.)
Coated or impregnated woven, knit, or nonwoven fabric which...
Coating or impregnation is water absorbency-increasing or...
C428S375000, C428S396000, C427S331000, C427S334000
Reexamination Certificate
active
06177367
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to a process for the hydrophilic finishing of fibers, which exclusively or predominantly contain polyolefins or polyesters, or of nonwovens containing polyolefin or polyester fibers and to fibers or nonwovens which are given a hydrophilic finish by this process.
In the manufacture of sanitary articles, such as diapers or sanitary napkins, absorbent materials are used to absorb aqueous liquids. In order to prevent direct contact with the absorbent material during wear and to increase comfort, the absorbent material is wrapped in a thin water-permeable nonwoven. The nonwovens used for this purpose are normally made of synthetic fibers, such as polyolefin or polyester fibers, because fibers such as these are inexpensive to produce, exhibit good mechanical properties and, in the case of polyolefin, can be heat-bonded. However, untreated polyolefin or polyester fibers are not suitable for this particular application because, in view of their hydrophobic surface, they are not sufficiently permeable to aqueous liquids. Accordingly, the fiber surface has to be made hydrophilic by a corresponding finish. It is also desirable that the hydrophilic finish of the fibers should remain intact for as long as possible without any reduction in the permeability to water of the nonwoven. If nonwovens of the type in question are made up, for example, into diapers, the diapers thus produced can be subjected to repeated stressing without becoming leaky. In this way, the wearing time of the diapers is increased and the waste caused by used diapers can be reduced accordingly.
U.S. Pat. No. 5,045,387 describes, for example, a formulation for the hydrophilic finishing of polyolefin fibers which contains a mixture of an alkoxylated ricinoleic acid derivative, a hydrogenated ricinoleic acid derivative, a C
18
fatty acid and a polyalkoxylated polymethyl siloxane. EP 372 890 B1 discloses fibers which contain polyolefins or polyesters and which have been treated with a finish containing a fatty acid diethanolamide, a polyether-modified silicone, a sorbitan fatty acid ester and a metal salt of an alkyl sulfonate. The disadvantage of finishes such as these lies above all in their high price. In addition, correspondingly finished fibers show poorer behavior in the nonwoven production process, particularly during thermobonding, which results in reduced strength of the nonwoven. According to DE 42 43 547 C2, certain quaternized fatty acid triethanolamine ester salts are suitable for the production of spin finishes for synthetic fibers. These compounds are physiologically safe and show good biodegradability. However, there is nothing in the cited document to suggest that the compounds in question are also suitable for the hydrophilic finishing of synthetic fibers. French patent application 96/2024 discloses water-based preparations with solids contents of 1 to 50% by weight which contain linear saturated fatty alcohols, wax esters, nonionic and/or amphoteric or zwitterionic emulsifiers and cationic surfactants and their use for the production of utility papers with improved softness and as softeners for cellulose and textile fibers.
The problem addressed by the present invention was to provide an improved process for hydrophilically finishing polyolefin- or polyester-containing fibers or nonwovens containing polyolefin or polyester fibers, the hydrophilic finish applied remaining intact, even after repeated wetting.
BRIEF SUMMARY OF THE INVENTION
It has now been found that these requirements are satisfied by a process in which the fibers or nonwovens are treated with a finish which contains quaternary ester amine salts and alkyl glycosides.
Accordingly, the present invention relates to a process for the hydrophilic finishing of fibers, which exclusively or predominantly contain polyolefins or polyesters, or of nonwovens which predominantly contain fibers such as these, characterized in that the nonwovens are treated with an aqueous dispersion of a finish which contains 50 to 95% by weight, based on the total weight of the finish, of at least one quaternary ester amine salt corresponding to formula (I):
in which R
1
is an aliphatic alkyl group containing 12 to 22 carbon atoms, R
2
is either a group (CH
2
)
n
—O—COR
1
or an alkyl group containing 12 to 22 carbon atoms, R
3
and R
4
independently of one another represent a group (CH
2
)
n
—R
5
, where R
5
is H or OH and n is a number of 1 to 3, and X is either a halide, methosulfate, methophosphate or phosphate ion, 5 to 50% by weight of at least one alkyl glycoside corresponding to the general formula RO(G)
x
, in which R is a primary linear or methyl-branched aliphatic radical containing 8 to 22 carbon atoms, G is a glycoside unit containing 5 or 6 carbon atoms and x is a number of 1 to 10, and 0 to 30% by weight of glycerol.
DETAILED DESCRIPTION OF THE INVENTION
The process according to the invention is suitable for fibers which exclusively or predominantly, i.e. more than 50% by weight of which, contain polyolefins or polyesters, and for nonwovens which predominantly contain fibers such as these, fibers exclusively containing polyolefins or polyesters being preferred. Nonwovens containing 100% by weight of polyolefin or polyester fibers are particularly suitable. Polyolefin fibers are among the most commonly used fibers for the production of nonwovens. Examples of suitable polyolefins are polypropylene, polyethylene or copolymers of ethylene or propylene with butadiene. Polyester fibers, mainly polyethylene terephthalate fibers, are also used. Besides the fibers mentioned, other synthetic fibers suitable for the production of nonwovens may also be used, including for example fibers of Nylon®. Fibers consisting of two or more components, for example polyester/copolyester fibers or polypropylene/polyethylene fibers, are also particularly suitable.
The nonwovens used in the process according to the invention may be produced by any of the known processes for producing nonwovens which are described, for example, in Ullmann's Encyclopedia of Industrial Chemistry, Vol. A 17, VCH Weinheim 1994 pages 572-581. Nonwovens produced either by the dry laid process or by the spunbonded process are preferred. The dry laid process starts out from staple fibers which are normally separated by carding into individual fibers and are then laid together by an aerodynamic or hydrodynamic process to form the unbonded nonwoven. The semi-finished nonwoven thus produced is then made up into the final nonwoven by a heat treatment known as thermobonding. To this end, the synthetic fibers are either heated to such an extent that their surface melts and the individual fibers are joined together at their points of contact or the fibers are coated with an additive which melts during the heat treatment, thus joining the individual fibers to one another. The bonds between the individual fibers are fixed by cooling. Besides this process, any of the other processes known for bonding nonwovens may of course also be used.
By contrast, the spunbonded process starts out from individual filaments which are formed by melt spinning from extruded polymers which are forced under high pressure through spinning jets. The filaments emerging from the spinning jets are bundled, stretched and laid to form a nonwoven which, normally, is then thermobonded.
The process according to the invention is particularly suitable for nonwovens produced by the spunbonded process or by the dry laid process.
In the process according to the invention, the fibers or nonwovens are treated with the finish of quaternary ester amine salt, alkyl glycoside and optionally glycerol by applying the finish to the fibers or to the nonwoven in the form of an aqueous dispersion preferably containing from 5 to 30% by weight of the finish, based on the total weight of the dispersion. Any of the methods and machines typically used in the textiles industry, for example a padding machine, may be used for this purpose. The nonwoven is first contacted with the aqueous dispersion in a bath
Cole Elizabeth M.
Drach John E.
Henkel Kommanditgesellschaft auf Aktien
Ruddock Ula C.
Trzaska Steven J.
LandOfFree
Process for providing fibers or nonwovens with a hydrophilic... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Process for providing fibers or nonwovens with a hydrophilic..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Process for providing fibers or nonwovens with a hydrophilic... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2495363