Patent Application
20170362770
The invention relates to a composition for permanent hydrophilic finishing of textile fibers and textile products made of the textile fibers such as non-wovens.
There exist various methods for producing non-wovens. When forming spun-bonded fabrics by means of spun-bonding or melt-blowing methods, the filaments formed from extruded polymers by melt-spinning are pressed through spinnerets under high pressure, stretched in a hot or cold air stream and piled into a non-woven. The non-woven can then be bonded chemically, mechanically or thermally. When producing airlaid non-wovens, staple fibers are used, which are first carded to form a fibrous web and then bonded chemically, mechanically or thermally.
In particular, hydrophilic non-wovens are used as covering non-wovens or as an intermediate non-woven for sanitary products such as diapers, sanitary towels, incontinence products and similar products. The function of such non-wovens is to quickly transfer body fluids such as urine and blood to the underlying absorption layer.
To produce hydrophilic non-wovens, mostly fibers or filaments made of thermoplastic polymers such as polyolefin or polyester are used. However, these polymers are hydrophobic and have thus to be provided with a hydrophilic finish either during fiber production and/or during further processing into a non-woven. Usually, hydrophilization is performed by treating the filaments with known spin finishings, which are then further processed into staple fibers and/or directly into non-wovens. Further, it is also common to treat the non-wovens with a hydrophilic finishing agent to form a so-called top coat prior to further processing them into a sanitary product.
The treatment of hydrophobic fibers, filaments or non-wovens with a hydrophilic spin finish or a hydrophilic finishing agent is to result in a hydrophilicity that is as permanent and constant as possible over a long period of useful life of the non-woven. Therefore, the hydrophilic spin finish or the finishing agent should well adhere to the hydrophobic non-woven and must not or only minimally be washed off by liquids. Modern non-wovens should exhibit permanent hydrophilicity and be capable of being repeatedly wetted with water or body fluids such as urine.
So far, the compositions for the hydrophilic finishing of fibers and non-wovens for sanitary applications have been sold either as almost water-free oils or as diluted aqueous dispersions. The commercially available compositions are then diluted with water on-site during the production of the fibers or non-wovens, applied onto the fibers or non-wovens from the aqueous dilution and then dried.
However, the commercially available oils do not lead to a satisfactory permanent hydrophilic finish. The products provided with such a finish often show insufficient results in the wash-off test and have a tendency towards wet migration. Although aqueous dispersions show better results regarding the permanent hydrophilic finishing of textile fibers and non-wovens, the high water content of these dispersions can lead to bacterial contamination or hydrolysis of the components used and thus to a limited storage stability.
The patent DE 196 45 380 B4 discloses a composition for the permanent hydrophilization of polyolefin fibers comprising cationically modified siloxanes, esterquats and non-ionic surfactants. However, all commercially available compositions contain water and/or solvent and have only a limited storage stability.
In many commercially available compositions for permanent hydrophilic finishing of sanitary products anionic surfactants such as sulfosuccinates or liquid phosphoric acid esters are used to improve wetting. However, these components reduce the surface tension of the composition so much that for example urine in a wet diaper also wets the hydrophobic areas of the diaper and leaks from the diaper.
It is the object of the invention to provide a composition for permanent hydrophilic finishing of textile fibers and textile products such as non-wovens that provides better leakage protection and has improved storage stability.
This object is resolved by a composition for permanent hydrophilic finishing of textile fibers and textile products exhibiting the features of claim 1.
Further advantageous embodiments are stated in the sub-claims which can, optionally, be combined with each other.
The composition for the permanent hydrophilic finishing of textile fibers and textile products according to the invention consists of:
the composition having a melting point of at least 45° C.
The composition according to the invention can advantageously be dispersed in water and applied from aqueous dilution onto the fibers or non-wovens to be hydrophilically finished at the customer's facility. Provision as a composition having a melting point of at least 45° C. ensures sufficient storage stability.
The composition according to the invention exhibits a permanent hydrophilic finish of textile fibers and textile products that is comparable to the performance of spin finishes and finishing agents based on aqueous dispersions, while retaining the respective application properties.
The composition according to the invention is preferably present in the form of a granulate allowing both a reduction of the storage and transportation costs and simplified handling at the customer's facility. In addition, when present in the form of a granulate, the composition is less prone to modified storage conditions.
Alternatively, the composition according to the invention can also be provided as an aqueous dispersion having a solids content of at least 10 weight percent, preferably at least 15 weight percent. Again, the storage stability is distinctly improved as compared to diluted aqueous dispersions.
It is particularly preferred that the melting point of the composition is at least 55° C.
The upper limit of the melting point of the composition according to the invention depends on the components used and the dispersion capacity as well as the desired application properties of the composition. The inventors understand that compositions having a melting point of more than 120° C., preferably more than 90° C., can no longer be reasonably used as finishing agents for textile fibers and textile products.
Mostly, components made of highly viscous or solid materials are used to form the composition according to the invention. Despite this, the application properties of the non-wovens finished by the composition according to the invention such as multiple strike-through, multiple run-off, wetback, dry migration, wet migration and wash-off are not affected or even improved as compared to the compositions used so far. The fibers and non-wovens treated with the composition according to the invention show a good permanent hydrophilicity and a good absorption rate.
With respect to the invention, the term “fibers” does also comprise “filaments” including single filaments and multi-filaments. Thus, the terms “fibers” and “filaments” are used as synonyms.
Fibers, materials or surfaces which cannot be spontaneously wetted with water or have a contact angle of more than 90°, are called “hydrophobic”. Hydrophilic fibers, materials and surfaces can be spontaneously wetted with water and aqueous liquids or have a contact angle of less than 90°.
With respect to the invention, a textile product (fiber or fabric) treated with a finishing agent is considered “permanently hydrophilic” if it passes the multiple strike-through test pursuant to the WSP standard 70.7 (11) with strike-through times of <2/<3/<5/<5/<5 seconds.
Storage stability of the dispersions known from the state of the art is up to approximately 6 months. The compositions according to the invention can be stored for at least 12 months at 22° C. and 50% relative humidity without any deterioration of the product properties, measured by the performance in the multiple strike-through test. Even in the form of highly concentrated dispersions having a solid content of at least 10%, preferably at least 15%, the compositions according to the invention still remain pourable under these conditions. The compositions are preferably present as a granulate, and are considered storage stable if the appearance of the granules does not change after warm storage for 3 days at 50° C.
In particular, synthetic fibers or filaments made of polyolefins such as polyethylene and polypropylene and polyesters such as polyethylene terephthalate (PET) and polylactides (PLA) or bicomponent fibers made of polyolefines and polyesters are used as textile fibers. The textile products made of these fibers are especially non-woven textile products, in particular non-wovens.
For the production of the composition according to the invention the acidic phosphoric acid ester is melted and neutralized while stirring. Subsequently, the other components of the composition are added and mixed with each other while stirring. Any water that may be present from neutralization of the phosphoric acid ester is evaporated until a residual water content of less than 5 weight percent is reached. Then, granulation or scaling from the melt is performed; to this end various granulation techniques or scaling methods known from the state of the art can be used.
Below, the invention is explained by means of several preferred embodiments, which, however, are not to be considered as limiting.
According to a first embodiment of the invention the phosphoric acid ester according to component (A) of the composition preferably corresponds, in its acidic form, to the following formula (I):
P(═O)(OR1)(OR2)(OR3) (I)
wherein
R1, R2 and R3 are, independently from each other,
All suitable bases such as LiOH, NaOH, KOH, NH3, amines and mono-, di- or trialkanolamines, in particular mono-, di- or triethanolamine, can be used as neutralizing agents for the phosphoric acid ester of component (A).
According to a preferred embodiment at least one of the residues R1, R2 and R3 in formula (I) is an alkyl group or an alkenyl group having 12 to 28 C-atoms, particularly preferably 12 to 24 C-atoms.
Mono- and diphosphoric acid esters of saturated fatty alcohols having 12 to 24 C-atoms are particularly preferred.
According to another embodiment at least one of the residues R1, R2 and R3 in formula (I) of the phosphoric acid ester can include an alkoxylated alkyl or alkenyl group having 12 to 28 C-atoms in the hydrocarbon chain and 1 to 6 alkoxy groups, in particular ethoxy groups. Alkoxylated alkyl or alkenyl groups having 12 to 24 C-atoms in the hydrocarbon chain and 1 to 4 alkoxy groups, in particular ethoxy groups, are especially preferred.
In all embodiments the chain length of the alkyl groups or alkenyl groups in the residues R1, R2 and R3 of the phosphoric acid ester of formula (I) is preferably, on average, 14 or more C-atoms, more preferably 16 or more C-atoms and particularly preferably 14 to 18 C-atoms.
The melting point of the neutralized phosphoric acid ester of component (A) is preferably at least 50° C.
The residues R1, R2 and R3 can be the same or different. Mixtures of various phosphoric acid esters can also be used.
The proportion of component (A) in the composition according to the invention is in the range of 25 to 85 weight percent, preferably in the range of 40 to 70 weight percent, particularly preferably in the range of 60 to 70 weight percent, based on the total weight of the composition. A higher proportion of component (A) can result in an increased wet migration and a deterioration of the leakage behavior of a product provided with the composition as a finish.
According to the invention, the consistency enhancer according to component (B) of the composition is selected from the following group of compounds:
The hydrocarbon chains of these compounds can each be branched or linear, saturated or unsaturated. Preferably, the compounds used as consistency enhancers in the compositions according to the invention include at least 16 C-atoms in the hydrocarbon chain.
The alkoxy groups of the above mentioned compounds are preferably ethoxy (EO) groups and/or propoxy (PO) groups.
Preferably, the compounds contain up to 15 alkoxy groups, in particular EO and/or PO groups. The number of alkoxy groups is preferably 1 to 15, more preferably 2 to 10 and particularly preferably 2 to 8.
Preferably, the non-ionic consistency enhancer according to component (B) of the composition according to the invention has a melting point of at least 55° C.
Preferably, the consistency enhancer is an ester of C12-C28 fatty acids with polyfunctional alcohols selected from the group consisting of sorbitol, neopentylglycol, glycerol, trimethylolpropane, pentaerythritol and polyglycerol, glucose and polyglycosides and any mixture thereof.
The esters may or may not be alkoxylated. Non-alkoxylated fatty acid esters of the polyfunctional alcohols are preferred.
Alkoxylates of polyfunctional alcohols are preferably alkoxylates of sorbitol, neopentylglycol, glycerol, trimethylolpropane, pentaerythritol and polyglycerol, glucose and polyglycosides and any mixture thereof having 1 to 15 alkoxy groups, in particular ethoxy groups and/or propoxy groups.
C12-C22 alkyl polyglycosides, especially C12-C22 alkyl polyglucosides, and solid C16-C28 fatty alcohols and fatty alcohol alkoxylates or alkoxylates of functionalized fatty alcohols having 12 to 28 C-atoms in the hydrocarbon chain and 1 to 15 alkoxy groups, in particular ethoxy and/or propoxy groups, are also suited as consistency enhancers. An example of a functionalized fatty alcohol is hydroxystearyl alcohol.
Further, a solid fatty acid amide having 12 to 28 C-atoms in the hydrocarbon chain can be used as a consistency enhancer in the composition according to the invention. The fatty acid amide is especially free of nitrosamines. An example of a suitable fatty acid amide is stearic acid monoethanol amide.
Preferably, the alkoxylated C12-C28 fatty acids and fatty acid esters include up to 15 alkoxy groups, more preferably 1 to 10 alkoxy groups.
The fatty alcohol alkoxylates and fatty acid alkoxylates can include a terminal hydroxyl or alkyl or alkenyl ether group. Hydroxy group-terminated fatty alcohol and fatty acid alkoxylates are particularly preferred.
The non-ionic consistency enhancer can be used as a single compound or as a mixture of various compounds.
A proportion of the consistency enhancer of 50 weight percent of the total composition should not be exceeded as an excessive amount of the consistency enhancer can result in a poor wetback, a low absorption rate and insufficient permanent hydrophilization. Preferably, the proportion of the consistency enhancer is in the range of 10 to 40 weight percent, particularly preferably in the range of 15 to 30 weight percent, based on the total weight of the composition.
The hydrophilically modified polyalkylsiloxane of component (C) can be cationically or anionically modified or exhibit a non-ionic hydrophilic side group.
According to a preferred embodiment of the invention component (C) preferably comprises a cationically modified polyalkylsiloxane having at least one quaternary ammonium group.
It is particularly preferred that the cationically modified polyalkylsiloxane corresponds to one of the below formulas IIa or IIb:
wherein
R4 is
r and s are, independently from each other, an integer from 1 to 50;
Cationically modified polyalkylsiloxanes in which the residue R4 bears a free cation are preferred. Alternatively or additionally polyalkylsiloxanes which exhibit an amphoteric betaine structure on the residue R4 can be used.
According to another embodiment the hydrophilically modified polyalkylsiloxane of component (C) comprises a non-ionic alkoxylated polyalkylsiloxane having an α,ω structure or comb structure, optionally terminated by alkyl groups, acyl groups or phosphate groups.
Preferably, the hydrophilically modified polyalkylsiloxane has a viscosity of at least 3,500 mPa s at 25° C. Particularly preferably, the viscosity of the polyalkylsiloxane at 22° C. is at least 5 Pa s and is preferably in the range of 5 to 100 Pa s, especially between 50 and 80 Pa s. The viscosity is measured pursuant to DIN ISO 2555.
Suitable, highly viscous, hydrophilically modified polyalkylsiloxanes are, for example, commercially available under the designation TEGOPREN™ from Evonik Industries or as L grade silicone oils from Wacker AG. The hydrophilically modified polyalkylsiloxane of component (C) improves the absorption capacity of the products provided with the composition according to the invention as a finish.
The proportion of component (C) in the composition according to the invention is in the range of 3 to 35 weight percent, preferably in the range of 5 to 25 weight percent and particularly preferably in the range of 10 to 15 weight percent, based on the total weight of the composition. A higher proportion of component (C) deteriorates the composition's granulation capacity and increases the price.
According to another embodiment the composition can include a dispersion additive as component (D) to stabilize the granules and improve their dispersibility in water. Preferred dispersion additives are hydrotropic compounds, in particular substances from the group of C6-C18 alkyl alkoxylates that are liquid at room temperature, which can be branched, linear, saturated or unsaturated and include up to 6 ethoxy and/or propoxy groups, and amphoteric surfactants, especially betaines, (poly)phosphates, in particular polyphosphate alkaline salts and/or sulfonates such as alkyl sulfonates and cumene sulfonates. Further suitable dispersion additives are polyvinyl alcohols and polyacrylates. The addition of hydrotropic substances can also lower the viscosity of the composition in an aqueous dispersion.
According to an embodiment of the composition according to the invention sodium-polyphosphate is used as a dispersion additive.
Preferably, the composition is present in the form of a granulate. It is preferred that the granulate is free-flowing. Preferably, the medium grain size of the granules is in the range of 4 to 10 mm.
The composition according to the invention is preferably used as a spin finish for providing a permanent hydrophilic finishing of polyolefin fibers or polyolefin filaments or as an agent for providing a permanent hydrophilic finishing of non-woven textile fabrics, especially spun-bonded non-wovens, made of polyolefin fibers or polyolefin filaments.
Preferably, ethylene- or propylene-based homo- or copolymers can be used as a polyolefin.
Examples of such polyolefines are polyethylenes such as HDPE (high-density polyethylene), LDPE (low-density polyethylene), VLDPE (very low-density polyethylene), LLDPE (linear low-density polyethylene), MDPE (medium-density polyethylene), UHMPE (ultra-high molecular polyethylene), VPE (crosslinked polyethylene), HPPE (high-pressure polyethylene); polypropylenes such as isotactic polypropylene; syndiotactic polypropylene, polypropylene produced by metallocene catalysis, impact-modified polypropylene; ethylene- and propylene-based random copolymers, ethylene- and propylene-based block copolymers; EPM (poly[ethylene-co-propylene]); EPDM (poly[ethylene-co-propylene-conjugated diene]).
Further suitable polyolefines are, for example, polystyrene; poly(methylstyrene); poly(oxymethylene); metallocene-catalyzed alpha-olefin or cycloolefin copolymers such as norbornene-ethylene copolymers; copolymers which contain at least 60% ethylene and/or styrene and less than 40% monomers such as vinyl acetate, acrylic acid ester, methacrylic acid ester, acrylic acid, acrylonitrile or vinyl chloride. Examples of such polymers are poly(ethylene-co-ethyl acrylate), poly(ethylene-co-vinyl acetate), poly(ethylene-co-vinyl chloride) and poly(styrene-co-acrylonitrile).
Graft copolymers and polymer blends, i.e. mixtures of polymers in which, amongst others, the above mentioned polymers are contained, for example polyethylene- and polypropylene-based polymer blends, are also suitable.
Further, the composition used according to the invention is suitable for providing a permanent hydrophilic finishing of polyester fibers, in particular of fibers made of polyethylene terephthalate and polylactides, and of non-wovens made thereof. Bicomponent fibers made of polyolefines and polyesters are also suitable.
For use as a spin finish or finishing agent, it is preferred that the preferably granular composition is dispersed in water or another suitable solvent and applied to the fiber or the non-woven in the form of a diluted aqueous dispersion containing active components in a proportion of 1 to 5 weight percent. The dispersion can be applied onto the non-woven by known means such as dosing pens, kiss rollers, immersion baths or by spraying. The composition's oil pick-up (OPU) is preferably in the range of 0.1 to 5%, based on the dry weight of each product (fiber, filament, non-woven).
Another object of the invention comprises textile fibers and filaments and textile products made thereof, especially nonwovens, that are produced by the above mentioned method and provided or treated with the composition according to the invention as a permanent hydrophilic finish.
The invention also comprises a double finishing and treatment of textile fibers and non-wovens made of polyolefin and/or polyester, in which first the fibers and filaments are provided with a permanent hydrophilic finish and then the non-woven made thereof, as a whole, is once again treated according to the invention with the composition as a permanent hydrophilic finish.
According to a preferred embodiment the non-woven provided with the composition according to the invention as a finish forms part of an absorption article. A device is called an absorption article if it is to be positioned on the skin of a wearer to absorb and retain the various substances excreted by the body. Examples of absorption articles are incontinence articles such as diapers, pant-like diapers, training pants, diaper holders and incontinence panties as well as feminine hygiene products such as tampons, sanitary towels and panty liners.
The absorption article usually comprises a basic unit made of a liquid-permeable top layer and a bottom layer as well as an absorption core located between the top layer and the bottom layer that serves to absorb body fluids. The liquid-permeable top layer is directed towards the wearer if he/she is wearing the article. The opposite bottom layer is located on the side that points to the clothing of the wearer. At least the top layer is made of a non-woven provided with the composition according to the invention as a finish.
The following exemplary embodiments serve to illustrate the invention and are not to be considered as limiting.
To produce the compositions specified in the following Table 1 the acidic phosphoric acid ester was melted and neutralized with KOH while stirring. Then the other components were added and mixed with each other while stirring. Any water present from neutralization of the phosphoric acid ester was evaporated until the melt reached a residual water content of less than 5 weight percent. Granules of a medium grain size of approximately 5 mm were obtained from the melt. A 5% aqueous dispersion was produced from the granules so obtained. This dispersion was applied onto a SSS spun-bonded non-woven made of polypropylene fibers having a weight per unit area of 15 g/m2. The oil pick-up in Examples 1 and 2 was set to 0.5%, based on the dry weight of the non-woven.
For comparison with the compositions according to the invention a finishing agent commercially available as an aqueous dispersion was set to a content of active components of 5% and applied with an OPU of 0.5% onto a SSS spun-bonded non-woven made of polypropylene fibers having a weight per unit area of 15 g/m2.
For testing the compositions pursuant to Examples 1 and 2, in conjunction with the PP spun-bonded non-woven provided with them as a finish, and the commercially available product used as a comparison, the tests described below were performed.
Multiple Strike-Through
Pursuant to standard test EDANA WSP 70.7 (11) the time needed for 5 ml of a synthetic urine solution to permeate a prepared non-woven and to access the underlying absorption layer made of filter paper is measured. The measurement is performed on the same non-woven fife times in a row, with the absorption filter paper changed every time, to test whether the hydrophilizing finish is washed off or is indeed permanently hydrophilizing. The five measured values are stated in seconds. A permanent hydrophilization is deemed achieved if the measured values meet the following limits: <2/<3/<5/<5/<5.
Multiple Run-Off Test
Following WSP method 80.9 the PP spun-bonded non-woven is put on a filter paper serving as an absorption layer at an angle of 25°. A defined amount of a synthetic urine solution is applied. Any test liquid that is not adsorbed is collected in a collecting tray and the amount is determined by weighing. The test is repeated twice on the same non-woven. Ideally, the amount of artificial urine solution not absorbed should be 0% in the first run.
10 Drop Test
In the 10 drop test according to an in-house test method a metal template having 10 wells is placed on a piece of non-woven as an absorption layer. 1 drop of a synthetic urine solution (0.9% NaCl) is successively added into each well of the metal template by means of a pipette. A test field is considered as passed if the amount of liquid is absorbed within 2 seconds by the underlying absorption layer. To obtain an assessment on the permanence of a fiber preparation, the test is repeated after a waiting time of 3 minutes without exchanging the absorption layer. The test result specifies the number of test fields passed.
Wash-Off Test
According to an in-house test method the surface tension of a wash solution resulting from the wash-off of a 6×6 cm piece of non-woven with 40 ml demineralized water is measured. The non-woven is stirred in the water for 10 seconds at room temperature (25° C.). Then, the non-woven is removed using tweezers and the surface tension of the washing water at 25° C. is measured by means of a platinum ring. The wash solution should exhibit a surface tension of at least 60 mN/m.
Wetback
Pursuant to standard test EDANA WSP 80.10 (09) A the amount (in grams) of liquid flowing back in dry filter paper laid across a wetted non-woven loaded with a 4 kg weight is measured. The wetback test is considered as passed if the amount of liquid flowing back is less than 0.6 g.
Dry Migration
During dry migration according to an in-house test method the migration of the hydrophilic fiber preparation components into surrounding hydrophobic non-woven material is simulated. To this end, alternating hydrophilic and hydrophobic layers are piled and stored under pressure (loading pressure 10 kg) at an increased temperature of 60° C. for 48 h. The hydrophobic layers of non-woven are placed into a solution of synthetic urine and the wetting of the layers of non-woven material is evaluated. Ideally, the hydrophobic non-woven is not wetted. Evaluation is performed by means of the following criteria:
Grade 1: no wetting visible;
Grade 2: a maximum of 5 wetted sites with a diameter of <2 mm visible;
Grade 3: 5 to 15 wetted sites with a diameter of <2 mm visible;
Grade 4: more than 15 wetted sites with a diameter of <2 mm or wetted sites with a diameter of >2 mm visible.
Wet Migration
During wet migration according to an in-house test method the detachment of fiber preparations and their transfer from hydrophilic to hydrophobic areas in contact with a liquid are tested. To this end, a hydrophilic piece of non-woven provided with a fiber preparation as a finish is placed into a petri dish with synthetic urine and a hydrophobic piece of non-woven is placed on top of it. After 30 seconds wetting of the hydrophobic non-woven is evaluated. Ideally, the hydrophobic non-woven is not hydrophilized. Evaluation is performed by stating the wetted surface in percent.
The test results obtained for the comparative example and the compositions according to Examples 1 and 2 are stated in Table 2 below.
Examples 1 and 2 according to the invention meet the requirements for a fast and permanent hydrophilization of the polyolefin non-woven.
In addition, the compositions according to the invention are storage stable for at least 12 months at room temperature and, in the form of granules, do not show any visible changes in the warm storage test for 3 days at 50° C.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2014 119 332.6 | Dec 2014 | DE | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2015/080796 | 12/21/2015 | WO | 00 |
