JPH02118179A - Elastic cotton fiber and related method therewith - Google Patents

Abstract

PURPOSE: To obtain a resilient cotton fiber by treating a fiber with a finish solution comprising a durable press resin and a lubricant, cross-linking and curing the resin in the interior of the fiber and maintaining the lubricant on the surface of the fiber. CONSTITUTION: In treating a scoured, bleached cotton fiber with a finish solution containing a durable press resin such as a formaldehyde-free alkylated glyoxyl/ cyclic urea condensate resin (a finish solution containing 3%-4% of the resin) and an amino functional group silicone such as a lubricant having a molecular structure larger than the molecular constitution of the resin (the finish solution containing 1.5-2.5% of the lubricant, the resin is absorbed in the interior of the fiber more readily than the lubricant, cross-linked with the fiber and cured. The lubricant is maintained in close proximity to the surface of the fiber to give a resilient cotton fiber. The fiber is useful as an absorption sheet for a diaper.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention This invention relates generally to methods of treating individual fibers to improve their resiliency, and more particularly to methods of treating individual fibers to improve their resiliency.
esin) and a lubricant to provide the fibers with improved resiliency and other properties suitable for fiber filler and other uses.

Background Art In textile technology, it is well known that woven fabrics made of cellulose fibers can be treated with urea-formaldehyde resins and other additives, including organopolysiloxanes, to provide wrinkle resistance (permanent pressing). It is. In particular, Grif'ffn U.S. Pat. No. 4,170,5
No. 81, Loo U.S. Patent No. 3.177.09
No. 3 and Spalding et al., U.S. Pat. No. 2,75L94B, use a formaldehyde-based glyoxyl resin as a crosslinking agent to provide a permanent press and an organic compound as a dust remover or water repellent. A representative example of the prior art teaching permanent press fabric processing using polysilokiones is seen.

To overcome the problem of free formaldehyde emission caused by permanently pressed woven fabrics, Worth, U.S. Pat. No. 4,269.
No. 803 teaches the use of a formaldehyde-free finish containing glyoxyl along with a reactive silicone and a catalyst. Apart from that,
North U.S. Patent No. 4.345.063
No. 1, which teaches permanent pressing using a formaldehyde-free alkylated condensation resin product by reacting glyoxyl with a cyclic urea.

In household clothing, it is desirable to use fibrous fillers that have good elasticity and can recover their original volume after multiple uses. Polyester fibers are commonly used because of their elasticity. Cotton fiber is cheap and feels comfortable to the touch.
While it may be desirable as a filler, it lacks the elasticity of polyester fibers, tends to clump and tangle after repeated use, and does not retain its original volume. Therefore, cotton and other natural fibers have not traditionally been suitable as fiber fillers for the household goods market. moreover,
For various types of absorbent layers and laminates, it is desirable to use fibers that can retain their original volume during use.

SUMMARY OF THE INVENTION The main object of the present invention is therefore to provide a method for treating fibers so as to improve the elasticity of the individual fibers. In particular, the present invention seeks to provide a process for treating cellulosic fibers, such as cotton fibers, to provide improved properties suitable for use as fiber fillers. Another object is to provide improved textile products made of individual fibers that have been treated to improve elasticity and maintain volume.

According to the invention, a method for treating fibers to improve the elasticity of individual fibers is characterized in that it consists of the following steps. That is, individual fibers are saturated with a solution containing a permanent pressing resin and a lubricant so that the interior of the fiber is saturated with resin, while the lubricant is retained at or near the surface of the fiber. and then drying and curing the resin so that it is crosslinked into the fibers before the lubricant can be absorbed inside the fibers. The lubricant is selected to have a larger molecular structure than the resin, so that the resin is more easily absorbed into the fibers than the lubricant.

In a preferred method of the invention, the refined and bleached cotton fibers are
Formaldehyde-free alkylated glyoxyl/
It is saturated with a solution containing a cyclic urea condensate resin and an amino-based silicone, and is dried and cured. The elasticity of the produced fibers is comparable to or better than polyester fibers. The resin component gives the treated fibers elasticity, while the silicone gives the fibers lubricity and reduces intrafiber friction.
Allow them to slide easily over each other.

In another aspect of the invention, the improved textile product comprises individual fibers finished with a permanent pressing resin and a lubricant;
In particular, it consists of individual cotton fibers within which the resin is saturated, cured, and crosslinked within the fibers, while the lubricant is retained at or near the surface of the fibers. The resiliency of finished cotton fibers, as measured by the compression recovery method of resiliency testing, is about 4.1 to 5.8 co+ or higher after initial compression, and about 4.8 co+ for polyester fibers. It is Ic1l.

Objects, features, and advantages of the pond of the present invention will become apparent from the following detailed description of the best mode of carrying out the invention when considered with reference to FIGS. 1A-4.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIGS. 1A and 16, two alternative methods of producing high modulus fibers according to the present invention are shown generally consisting of the following steps. scouring and bleaching the raw and unfinished fibers; saturating the fibers with a finishing solution containing permanent pressing resins and lubricants;
The process then involves drying and curing the fibers to produce a high modulus fiber product (sometimes referred to herein as a "high loft" fiber). The present invention applies to other cellulosic fibers such as cotton linters as well as other fibers that have been or will be treated to have a structure capable of absorbing and crosslinking permanent pressing resins. However, the following description uses the specific example of standard mature cotton fibers.

If the continuous process of Figure 1A is chosen, the bales of grey-yellow-green cotton fibers are opened and washed in a stage washer.

Form a worsted mat of cotton fibers. The mat is saturated in a caustic surfactant solution during the scouring step and passed through a scouring steamer at the appropriate temperature and time required to remove basic impurities such as waxes, oils, pectins, etc. The mat is saturated in a bleaching solution, such as hydrogen peroxide or sodium hypochlorite, and passed through a bleach steamer at the appropriate temperature and time required to cause bleaching, bleaching the fibers white and removing the bleaching solution. Wash and adjust the pH of the fiber surface residue.

The scoured and bleached cotton fibers are then immersed in a finishing bath containing permanent pressing resins, lubricants, and catalysts. In this case, the fibers are soaked so that the resin is saturated into the interior of the fibers and the lubricant remains at or near the surface of the fibers. The finished fibers are then dried and cured within a period of time until the lubricant can be absorbed into the interior of the fibers.

The dried mat is crushed in a tufter and packaged as high loft cotton fibers.

Continuous processes rely on the use of conveyors and other auxiliary equipment to convey the worsted mat of fibers through the process. The mat is preferably in the range of 24 ounces per square yard. Higher weights help maintain fiber integrity during continuous processing. One advantage of this method is that it fixes the open web of fibers prior to scouring and bleaching to prevent the formation of lobes, strings, and neps associated with batched cotton fibers.

If you select the Kler method in Figure 16,
The bales containing gray-yellow-green cotton fibers are opened and washed in a stage washer. The fibers are then saturated with a caustic surfactant solution, the wet fibers are placed in a rotating tub, and the wet mixture is mechanically stamped to form large (eg, 600 pound) cakes to produce as homogeneous a cake as possible. This mixture is compressed in a hydraulic press to form a compressed cake of fibers with the appearance of a large donut.

The donut-like cakes are stacked in baskets and placed in a carrier that undergoes standard scouring and bleaching processes. The cakes are then removed from the car and each cake is dehydrated, for example by spinning, in a dehydrator to remove as much water as possible. This dehydrated cake is called Cake Attacker.
wet picker) or wet picker (νe
t picker) and grind into small moist tufts. At this stage, a finishing solution containing a permanent pressing resin, lubricant, and catalyst is applied to the fiber by spraying or dipping, and the fiber is placed in a dryer where it dries and hardens. Alternatively, the dewatered cake can be immersed directly in the finishing bath and then separated and formed into a mat for drying and curing. The fibers can also be passed through a release device to fluff them up into as many individual fibers as possible and then packaged and shipped.

In the present invention, the key factor in achieving improved fiber elasticity is that the resin is saturated into the interior of the fiber, cured, and crosslinked, while the lubricant remains at or near the surface of the fiber. . As shown in FIG. 2, cotton fiber has an outer skin and a core (lumen). The cotton fibers are scoured and bleached to remove the natural waterproof properties and make the fibers absorbent.
Allow the fibers to quickly absorb the resin into their interior. Lubricants also tend to be absorbed inside the fibers. Therefore, the resin is selected to have a smaller molecular structure than the lubricant, so that the resin is more easily absorbed internally, while the lubricant remains on the surface of the fibers.

If the fibers are dried and allowed to stand for a long time before curing, for example 7-8 hours or more, the lubricant can be gradually absorbed into the fibers. In this way, the desired elasticity of the fibers will be diminished.

Furthermore, the lubricity of the fibers also appears to be reduced. Therefore, drying of the fibers before curing must be within a relatively short time.

The finishing solution applied to the fibers within the above process is 1.0
~4.0% alkylated glyoxyl/cyclic urea condensation resin, preferably free of formaldehyde, with 2.5-4.0% being the most preferred range, in water as the carrier medium and as the catalyst. Preferably it contains 1.5-2.5% reactive silicone and 0.6-0.7% magnesium chloride hexahydrate.

Formaldehyde-free alkylated glyoxyls are prepared by reacting cyclic ureas with glyoxyls in the presence of a catalyst to form water-soluble oligomeric condensates, as disclosed by North in U.S. Pat. No. 4,345,063. /A cyclic urea condensate resin is obtained. By reacting this condensate with an alcohol, the condensate is fully or partially alkylated. Separately, glyoxyl is reacted with an alkylated cyclic urea. The reaction product is a formaldehyde-free resin suitable for application as a finish to cellulose fibers as described above. Other resins that can be used include glyoxyl (DM
In addition to formaldehyde-containing resins such as DHEU resin, melamine resins are also included.

However, glyoxyl resins are undesirable in household or skin contact products because they emit formaldehyde. The resin must also be selected so that it does not adhere to the fibers.

Lubricants not only have a larger molecular structure than resin;
It is selected to have lubricity that can overcome even the internal surface friction of the fibers. It is suitable to use reactive silicones, especially amino-functional silicones. This is because it has an affinity for the hairy, scaly tips on the surface of cotton fibers and tends to cover them easily. Other lubricants that can be used include stearates such as butoxyethyl stearate or fatty acids. Catalysts are used to promote crosslinking of resin and fibers. Preferred catalysts include:
Includes metal salts such as magnesium chloride hexahydrate.

The drying process is carried out in drying cans that provide radiant heat, or in forced hot air or ovens. The fibers are dried to a moisture content of less than 5% before curing. Cure temperature is approximately 280"F to approximately 360'F
The curing time can be varied from about 30 seconds to 60 seconds depending on the temperature. The preferred curing temperature is about 300-320°F. Curing temperature is 360°
Above F, the silicone or resin finish on the cotton fibers may appear brown or yellow.

The resulting finished fibers were improved in elasticity by compression recovery method.
1, it turns out that the elasticity is improved. According to FIG. 3, the fiber sample in the cylinder is compressed with a plunger and measured values are taken. In the comparative tests conducted here, 1 gram fiber samples were cut into strips and inserted into standard 3/4 inch test tubes. Hold the test tube vertically, insert a plunger with a 1 pound weight into the test tube,
Compress the fiber sample under gravity. After a waiting period (5 minutes), the compressed height of the fiber is measured and the plunger is removed. After the recovery period (5 minutes), the recovery height of the fibers is measured. The difference between compression height and recovery height is considered a measure of fiber elasticity.

Examples of cotton fibers treated with the range of finishing formulations according to the invention are shown in Table 1. The alkylated glyoxyl/cyclic urea condensation resin used was manufactured by Chester, Southern California.
Sequa Chem (star)
It was ZF-4 sold by ical). The silicone used was Sefa Soft-89 silicone, and the catalyst was #531.3, also sold by Sefa Chemical Co.
It was a 0% magnesium chloride hexahydrate solution. As a comparative example, cotton fibers treated only with a surfactant (Sefa Chemical's 8634 positive soap) and polyester fibers (PET) were also subjected to elasticity measurements.

Table 1 #1 #2 #3 #'4 #5 #6 Fiber Cotton Cotton Cotton Cotton Cotton, (I + Ester resin 3.0% 4.0% 3.0% 3.
0% C') Corn 1.5% 2.0% 2.5%
1.5% catalyst 0.6% 0.7% 0.
61% 0.6% surfactant
As shown in the graph in Figure 4, the elasticity of the treated cotton fibers in Table 1 showed a measured recovery of 4.1 to 5.8 cm or more; 2.4 ct for cotton fiber (only agent) and 4 ct for polyester fiber.
．． It was 1cn+. Thus, the resin/silicone finishing treatment provided cotton fibers with superior resiliency, comparable to or substantially greater than polyester fibers. Other tests on untreated cotton fibers using amounts of resin up to 3.0% have also shown that polyester fibers exhibit improved resiliency over unfinished cotton fibers, if not significantly higher. It was done. Similar results are obtained with other types of cellulose fibers such as cotton linters and other fibers.

The permanently pressed resin/lubricant treated fibers according to the invention have not only lubricity but also increased elasticity properties and can easily slide 17 over each other to maximize the elasticity effect. Treatment with resin alone imparts a lower elasticity to the cotton fibers, ranging from 1/3 to 1/2 that of cotton fibers treated with resin and lubricant. Bleached cotton fibers tended to pick up 100% of the resin and lubricant from the finishing solution. Therefore, the treated fibers produced preferably have about 0.675 to 1.8 grams of resin per 100 grams of fiber. The preferred range of silicone was about 0.13 to 1.125 grams per 100 grams of fiber. Even with formaldehyde-free alkylated glyoxyl/cyclic urea condensate resins, formaldehyde was almost completely removed from the finished article, i.e., below trace amounts.

The absence of formaldehyde allows the treated fibers to be safely used as fiber fillers in household products and applications involving contact with the skin.

Further increases in the elasticity of the finished fibers result in increased softness and increased void volume maintained around the fibers. Treated fibers can therefore be advantageously used to produce soft, high-loft fill layers in laminates and textiles. The elastic fibers can also be used to form highly absorbent layers due to their ability to maintain a void volume around the fibers and to absorb and retain moisture in the void volume. For example, the elastic fibers can be mixed with absorbent fibers such as wood bulb fibers, superabsorbent polymer particles or other absorbents. The elastic fibers maintain the void volume used by the absorbent to absorb moisture, thereby increasing the absorbent capacity of the layer. If the fibers are treated with a hydrophilic lubricant such as glycerin or diethyl stearate,
The absorbent capacity of the fibers is retained, thereby increasing the total absorbent capacity of the layer.

Absorbent layer constructions using elastic-finished fibers are superior to untreated cotton fibers or even synthetic fibers due to the enhanced elasticity and lofted volume of the finished fibers. It can have greater absorption capacity than conventional superabsorbent layers.

Applications suitable for this absorbent layer composition include absorbent sheets for diapers, sanitary napkins, absorbent sheets, tissues, towels, and the like.

Although preferred embodiments of the invention have been described, it should be understood that many modifications and variations are possible within the scope of the principles of the invention. All such embodiments, modifications, and variations are considered to be within the spirit and scope of the invention as defined in the following claims.

[Brief explanation of drawings]

FIG. 1A is a schematic illustration of a continuous process for treating individual fibers with a resiliency-improving finish according to the present invention. FIG. 16 is a schematic illustration of a batch process for treating individual fibers with a resiliency-improving finish. FIG. 2 is a cross-sectional view of cotton fibers finished according to the present invention. FIG. 3 is a schematic diagram showing a method for testing the elasticity of finished fibers. FIG. 4 is a drawing comparing the elasticity of finished cotton fibers with the elasticity of untreated cotton fibers and polyester fibers.

Claims (1)

[Claims] 1. Saturating individual fibers with a finishing solution consisting of a permanent pressing resin and a lubricant such that the resin is saturated into the interior of the fiber while the lubricant is at or near the surface of the fiber. to improve the elasticity of the individual fibers, characterized by drying and curing the resin that is crosslinked with the fibers before the lubricant can be absorbed into the interior of the fibers. How to process. 2. The lubricant is selected to have a larger molecular structure than the resin, so that the resin is more easily absorbed into the fibers than the lubricant. The method described in. 3. The method according to claim 1, characterized in that the fibers to be finished are scoured and bleached cotton fibers. 4. The method according to claim 1, wherein the permanent pressing resin is an alkylated glyoxyl/cyclic urea condensation resin. 5. A method according to claim 4, characterized in that the resin is provided in an amount of 3.0% to 4.0% of the finishing solution. 6. The method according to claim 1, characterized in that the lubricant is an amino-functional silicone. 7. The silicone is 1.5 to 2.
7. Method according to claim 6, characterized in that it is provided in an amount of 5%. 8. The method of claim 1, wherein the finishing solution further comprises a catalyst to promote crosslinking of the resin. 9. The catalyst is 0.6% to 0.7% of the finishing solution.
9. Process according to claim 8, characterized in that it is a 30% magnesium chloride hexahydrate solution provided in an amount of . 10. further comprising the successive steps of forming a worsted mat of cotton fibers, scouring and bleaching the cotton fiber mat, then saturating the cotton fiber mat with the finishing solution, and drying and curing the fibers. Process according to claim 1, suitable for the treatment of cotton fibres, characterized in that: 11. Form a compressed cake of cotton fibers, scouring and bleaching the cotton fiber cake in a carrier, dewatering the washed cotton fiber cake, separating the cotton fibers into small tufts, and applying a finishing solution to the cotton fibers. 2. A method according to claim 1, suitable for the treatment of cotton fibers, characterized in that it comprises a batch step of coating and then drying and curing the fibers. 12. The resin is saturated, cured, and cross-linked inside the fiber, while the lubricant is maintained at or near the surface of the fiber so that the elasticity of the finished fiber is improved over that of the untreated fiber. A finished textile product comprising individual fibers having a permanent pressing resin and a lubricant finish. 13. The lubricant is selected to have a larger molecular structure than the resin, so that the resin is more easily absorbed into the fibers than the lubricant. Improved textile products described in . 14. The improved textile product according to claim 12, characterized in that the fibers are cotton fibers. 15. The improved textile product according to claim 14, wherein the resin is a formaldehyde-free alkylated glyoxyl/cyclic urea condensate resin. 16. The cotton fiber has a content of 0.675 to 100 g per 100 g of fiber.
characterized by having a finish of 1.8 g of formaldehyde-free alkylated glyoxyl/cyclic urea condensate resin and about 0.13 to 1.125 g of amino-functional silicone as a lubricant per 100 g of fiber,
The improved fiber product of claim 15. 17. The elasticity of the finished fibers is about 4.1-5.8 cm after initial compression using the compression recovery test method, compared to about 4.1 cm for polyester fibers.
Improved textile product according to claim 15, characterized in that the recovery is greater than or equal to cm. 18. Improved textile product according to claim 12, characterized in that the finished fibers are used as fiber filler. 19. Improved textile product according to claim 12, characterized in that the finished fibers are used to form an absorbent layer. 20. The improved textile product according to claim 12, wherein the lubricant is a hydrophilic lubricant.