FI74745C - CELLULOSABASERADE FIBER, ISYNNERHET FOER FRAMSTAELLNING AV FIBERDUKAR, FIBERDUKAR INNEHAOLLANDE DYLIKA FIBRER OCH FOERFARANDE FOER FRAMSTAELLNING AV FIBRERNA. - Google Patents

Description

74745

The invention relates in particular to cellulose-based fibers having a low water retention capacity, a high immersion time, a low water retention capacity, a low absorbency and containing minerals, which are particularly useful for the production of non-fibrous mats. , such fibers include 10 mats and a method of making the fibers.

Fibers of this type are mainly used for coated fiber mats for children's diapers, other types of diapers, sanitary napkins, incontinence dressings, bedding and similar disposable products, and stuffed fiber mats.

For example, it is known from CH patent publication 487 641 to use binder-containing non-woven mats made of viscose and / or polyester staple fibers for coated fiber mats. Recently, viscose, polyester and / or polypropylene staple fibers bonded with binder fibers have become increasingly important. According to the latest information, the use of synthetic fiber spinning mats has increased in the above-mentioned field of application.

25 In addition to the required non-fibrous mechanical properties such as dry and wet strength, breaking energy and puncture resistance, non-fibrous mats are now required to have hydrophobic properties. Based on numerous published works presented at EDANA (European Disposables 30 And Nonwovens Association) presentations, the following three non-fibrous dimensions are used to determine these properties: - droplet depression time - Wet Retention 35 - 745 Stain-Test

The droplet depression time is a measure of the primary wetting of the uncoated fiber and is measured in seconds.

Liquid absorption expresses the amount of liquid received and retained by the coating fiber 5 'under the test conditions as a percentage of the weight of the dry coating fiber.

In back-wetting, the discharge of liquid through the coating fiber mat onto the absorbent paper thereon is determined and expressed as a measured value as a spot area in cm.

Based on the test methods used to describe these hydrophobic properties, coating fiber mats are required to have the shortest possible droplet depression time, the lowest possible liquid-15 absorption, and the lowest possible back-wetting. Synthetic fibers generally better meet these requirements in terms of liquid absorption and rewetting than, for example, viscose fibers. In contrast, primary wetting, which occurs during a short period of droplet depression, is clearly more advantageous for viscose fibers than for synthetic fibers.

It is an object of the invention to provide cellulose-based fibers of the type initially mentioned, such as viscose fibers, which can be formed in particular into a fibrous mat having all the properties defined above.

This object is achieved according to the invention in that the fibers contain, as mineral fillers, barium sulphate, talc, muscovite or a mixture thereof in an amount of 15 to 60% s, preferably 40 to 50% by weight of the total fiber, and optionally additionally hydrophobic, polymeric or oligomeric substances such as polyethylene. polypropylene, polystyrene, polyacrylic acid ester, polytetrafluoroethylene or waxes from 1 to 60%, preferably from 25 to 50% of the total fiber mass.

35 The particle size of the mineral fillers 11 3 74745 contained in the fibers shall not exceed 3 μm. DE-A-8 2302 proposes that electro-osmotically purified kaolin, preferably 5 5 to 10%>, be added to the cellulose solution before it is formed into yarns or films, however, the addition of kaolin serves exclusively for dimming purposes. Suitable waxes for the fibers according to the invention are petrochemical, polyphonic or synthetic waxes.

The proportion of mineral fillers and / or polymeric or oligomeric substances in the fibers according to the invention adapts primarily to the desired hydrophobic fiber properties.

Preferably, the fibers comprise a mixture of mineral fillers and hydrophobic, polymeric or oligomeric substances in a weight ratio of 10:90 to 90:10, preferably 50:50 to 90:10, the mixture being present in a fiber mass of 1 to 00%, preferably 30 -50%.

According to another preferred embodiment, the fibers contain mineral fillers coated with hydrophobic, polymeric or oligomeric substances in a weight ratio of 75:25 to 99: 1, preferably 85:15 to 95: 5, these coated mineral fillers being present in the total amount of fibers from 1 to 60%, preferably 25 -25 50%.

While the reduction in hydrophilicity with the addition of mineral fillers is due to the low cost of reducing the hydrophilic groups of the cellulose forming the fibrous backbone compared to pure cellulosic fibers, the addition of hydrophobic polymeric or oligomeric materials is a matter of quantity. If a mixture of mineral filler and hydrophobic polymeric or oligomeric products, respectively, is added to the viscose, different degrees of water hydration are obtained depending on the mixing ratio of these two components in the resulting fibers of the invention.

The fibers are prepared according to the invention by mixing mineral fillers and optionally hydrophobic, polymeric or oligomeric substances or coated mineral fillers in the viscose - preferably as an aqueous suspension thereof - and spinning the mixture wet.

Preferably, mineral fillers or hydrophobic substances, respectively, in a particle or droplet size of less than 3 μm are used as the aqueous suspension in the presence of an alkali-stable emulsifier system. The alkali-stable emulsifier system, on the one hand, prevents the agglomeration of the particles after mixing with viscose and decomposes], on the other hand, most often in sulfuric acid spinning solution, so that the mineral fillers and finely divided hydrophobic, polymeric or oligomeric substances are formed without loss.

The nonwoven mat according to the invention is characterized in that it has, with a fiber titer of 1.7 dtex, a droplet depression time of up to 45 seconds, a liquid absorption of up to 90% 2 and a back moisture content of up to 55/75 cm or that it has a fiber titer of 3 , 3 dtex, a droplet depression time of up to 10 seconds, a liquid absorption of up to 25 45% and a back humidification of up to 40/65 cm.

The invention is further illustrated by the following examples.

The dimensions required to describe the fiber properties are as follows:,. · ^ Swollen fibers ^ cond. Fibers

thickness swelling /% = -5- x 10U

^ cond. fibers 35 D: fiber diameter ti 74745

Thickness swelling is determined microscopically in individual fibers and refers to an increase in the diameter of the water-swollen fiber relative to the moisture-controlled fibers.

5 o pulp at 25 ° C and 90% relative humidity

Water vapor absorption /% = ~ Jjuit ^ s ^ absolutely, in dry state χ1 fjU

fiber in an absolutely dry state

The fibers are stored at the indicated temperature and relative humidity until equilibrium is reached. The water absorbed is determined gravimetrically.

Immersion time and water retention (WHV) are the methods of analysis described in Deutsches Arz-neibuch (DAB), 7th edition, 1968. The immersion time is a measure of the wettability of the fibers 15 and is expressed in seconds, where good wettability is expressed by a short immersion time. The water holding capacity indicates the amount of water retained in the capillary spaces between the fibers in grams per gram of fiber.

The water retention capacity according to DIN 5381A is a measure of the water retained in the individual fibers after thorough immersion in water and subsequent centrifugation and is expressed as a percentage.

, ......,,, a centrifuged pulp - dry pulp.

Water retention /% = -—- x 100 2 5 dry pulp

Absorbency is determined by the Demand-Wettability test (B. M. Lichstein, 2nc * Annual Symposium on Nonv / door Product Development, March 197 ^, Washington D.C., 129-1JI2).

30

Example 1: To 1 kg of viscose containing 8-9% cellulose, 5 to 5.5% NaOH and 2 to 2.5% sulfur was mixed 115 g of an aqueous suspension of 30% barium sulphate 35 (Sachtleben Blanc Fixe Micro).

6,74745 This mixed viscose was spun in a spinning bath containing 100 - HOg I ^ SO ^ a, 3 ** 0 - 360g Na ^ O ^ a and 5 -10g ZnSO 4 ra per liter. The spinning bath temperature ranged from 0 to 50 ° C. The coagulated fiber cable was stretched in air at $ 50 for 50, cut into staple fibers, washed, bleached, braided and dried.

Fiber properties: titer (dtex) / staple fiber length (mm) 1.7 / ^ 0 10 fiber strength when wetted (cN / tex) 12.2 fiber elongation when wetted (%) 15.0 whiteness (BE) 65.0 barium sulphate content (?) 28.0 water retention (WRV) according to DIN 5381 ^ (%) 63.5 15 sinking time according to DAB 7 (s) 3.5 water retention (WHV) according to DAB 7 (g / g) 16.5 absorbency according to the Demand-Wettability test according to (ml / g) 8.1

The fibers were carded four times with the addition of 20% 30% thermoplastic heterophilic binder fiber (CHISSO ES) to achieve uniform distribution and thermally strengthened at about 200 ° C.

Fiber mat properties: 25 droplet pressing time (s) 0 liquid absorption (%) 55.0 p back-wetting (cm) 53/75

The fibers have a very high fiber-30 fiber attachment without softening, as evidenced by the high average maximum tape attachment and the high value of the attachment-slip range: average maximum 35 tape attachment (cN / tex) 45.8-62.1 attachment-slip range ( cN / ktex) 16.8

II

7 74745 Due to this high fiber-to-fiber attachment, it is possible to make needles for cleaning ears from the fibers according to the invention. Normally, only very fastened cotton is used for these needles.

The fiber according to the invention also has the punching property required for the production of round cotton sheets for cosmetics. The round batt sheets are cut from the fiber-10 mat with a special tool, in which case the batt sheets should have a characteristic embossed edge in order to largely prevent the fibers from fluffing during the use of the batt sheets. Traditionally, only natural cotton offers this northwestern feature.

15 Example 2:

The procedure is as in Example 1, but in addition to the barium sulphate suspension, 88 g of an aqueous emulsion containing 39% of polyethylene (Hoechst's polyethylene dispersion PE 30) are mixed with the viscose.

20

Fiber Features:

titer (dtex) / staple fiber length (mm) 1.7 / ^ 0 3.3 / bO

fiber strength when wetted (cN / tex) 10.3 9.9 fiber elongation when wetted (%) 10.5 11.5 25 whiteness (BE) 6l, 0 63.0 barium sulphate content (%) 27.8 27.5 polyethylene content {%) 18 , 2 18.9 WRV according to DIN 53814 (%) 57.5 52.3 Immersion time according to DAB 7. (s) 6.0 3.7 30 According to WHV DAB 7 (g / g) 15.0 15.5 Absorbency according to Demand-Wettability test (inl / g) 7.5 7.8

Nonwoven properties: 35 droplet depression time (s) 2 1 liquid absorption (%) 51 J19 back-wetting (cm ^) ^ 18/65> 8 74745

Example 3:

According to Example 1, but adding 128g of an aqueous dispersion containing $ 30 of wax-coated barium sulfate (90¾ from Blht Fixe Micro from Sachtleben, and 5% from MOBILCER 46 from Mobil), fibers and nonwoven mats were obtained, respectively.

Fiber properties: titer (dtex) / staple fiber length (mm) 1.7 / 40 3.3 / 60 10 fiber strength when wetted (cN / tex) 10.5 10.1 when stretched when wetted (%) 10.2 11.0 whiteness (BE) 64.0 65.0 Barium sulphate content (%) 27.5 28.0 Petroleum ether extractable content (%) 3.5 3.7 15 WRV according to DIN 53814 (%) 68.9 44.3 Immersion time according to DAB 7. (s) »» According to WHV publication DAB 7 (g / g) 0 0 absorbency according to Demand-Wettability test in (ml / g) 0 0 20

Nonwoven properties: droplet depression time (s) 43.0 7.0 liquid absorption {%) 31.0 24.0 2 back-wetting (cm) 7/34 26/57 25

Example 4:

According to Example 1, but adding 115 g of an aqueous suspension containing 30% talc (Naintscher Talkuin V 118/2) instead of a barium sulfate suspension, 30 fibers and nonwoven mats were prepared having the following properties, respectively:

Fiber properties: titer (dtex) / staple fiber length (mm) 3.3 / 60 35 fiber strength when wetted (cN / tex) 10.5 fiber elongation when wetted (%) 12.0

II

9 74745 whiteness (BE) 55.0 talc content {%) 27.3 WRV according to DIN 5381 ^ (%) 7 ^, 2 immersion time according to DAB 7. (s) 1.9 5 according to WHV DAB 7 (g / g) 16.2 absorbency according to Demand-Wettability test (ml / g) 8.3

Nonwoven properties: 10 droplet depression time (s) 0 liquid absorption {%) 59 2 back-wetting (cm) ^ 2/65

Example 5: According to Example 1, but adding 57 g of an aqueous dispersion containing 25 # of methyl methacrylate and 25 # of butyl acrylate (Hoechst acrylate dispersion AA 37) and 70 g of the barium sulfate suspension of Example 1, fibers and fiber mats were prepared, respectively.

Fiber properties: titer (dtex) / staple fiber length (mm 3.3 / 60 fiber strength when wetted (cN / tex) 11.0 25 fiber elongation when wetted (#) 15.0 whiteness (BE) 56.0

BaSO 4 content (#) 17.0 polyacrylate content (#) 13.8 WRV according to DIN 53814 (%) 69.0 Sinking time according to DAB 7. (s) 2.9 according to WHV DAB 7 (g / g) 14.5 absorbency according to Demand-Wettability test (ml / g) 7.4 • 35 Non-fibrous mat properties: droplet depression time (s) 2 liquid absorption (%) 53 2 back humidification (cm) 39/61 74745 10

Comparative Example:

Work was carried out as described in Example 1, but without the addition of barium sulphate.

5 Fiber properties: titer (dtex) / shear length (mm) 1.7 / 40 3 s3 / 60 fiber strength when wetted (cN / tex) 19.0 18.5 fiber elongation when wetted (%) 18.5 20.1 whiteness (BE) 63 .0 62.0 10 WRV according to DIN 53814 (%) 85.0 85.0 Immersion time according to DAB 7. (s) 2.5 2.2 WHV according to DAB 7 (g / g) 19.0 19.0 Thickness swelling (%) 37.0 37.0 Water vapor absorption at 20 ° C and 90% relative humidity ( %) 21.0 21.0 absorbency according to Demand-Wettab joining test (ml / g) 10.2 10.2

Nonwoven properties: 20 fiber titers (dtex) / staple cultures. (imi) _1.7 / 40 3.3 / 60 droplet depression time (s) 0 0 liquid absorption (%) 151.0 65.0 wetting (cmc) 73/92 47/71 25 It is seen that the conventional viscose fibers obtained according to the reference example have the invention significantly higher WRV compared to compliant fibers. much lower sink time, much higher WHV value 30 and higher absorbency than the fibers of the invention.

The fibrous mats made of the fibers according to the invention have sufficiently short or the same droplet depression times compared to nonwoven mats made of conventional viscose fibers, while the values of liquid absorption and rewetting are considerably lower.

Il

Claims (9)

1. Cellulose fibers with low water resistance, high sun time, low water-holding capacity, low suction capacity and having a mineral filler content, characterized in that the acidic mineral fillers contain barium sulphate, teak, blend scavenger or an amount of from 15 to 60%, preferably HO to 50% of the total fiber mass, and optionally additional hydrophobic, polymeric or oligomeric substances, such as polyethylene, polypropylene, polystyrene, polyacrylic acid ester, polyester, polytetrafluoroethylene or wax, in an amount of from 15 to 60%, preferably 25 to 50% of the total fiber mass distributed over the total fiber cross-section. Fibers according to claim 1, characterized in that they contain a mixture of mineral fillers and hydrophobic, polymeric or oligomeric substances in a pulp ratio between 10:40 and 90:10, preferably between 50:50 and 90:10. . Fibers according to claim 1 or 2, characterized in that they contain a mixture of mineral fillers and hydrophobic, polymeric or oligomeric substances in an amount of from 16 to 60%, preferably 30 to 50% of the total fiber mass. H. Fibers according to claim 1, characterized in that they contain mineral fillers, which are encapsulated with the hydrophobic, polymeric or oligomeric substances in a mass ratio between 75:25 and 60: 1, preferably between 85:15 and 95: 5th 5. Fibers according to claim 4, characterized in that the sheathed mineral filler is included in the total fiber mass in an amount of from 20 to 60 hours, preferably 25 to 50% of the total fiber mass. Fiber cloth with fibers according to any one of claims 1 to 5, characterized in that at a fiber titer of 1.7 dtex it has a dropping time of not more than 45 seconds, a liquid absorption of not more than 90% and a re-wetting.