US 3254940 A
Description (OCR text may contain errors)
United States Patent 10, 15 Claims. (Cl. 8116.3)
This application is a continuation-in-part of the Fritz Munzel U.S. application Serial No. 111,900, filed May 23, 1961.
This invention relates to an improved finished cellulosic textile product and to a process for very substantially enhancing certain of the physical or mechanical properties of a conventional crease-resistant finished cellulosic textile material. More particularly, it relates to an aldehydeor resin-finished cellulosic textile material exhibiting very substantially improved crease resistance, tensile or tearing strength and abrasive strength, and to a method whereby the properties of conventional aldehydeor resin-finished cellulosic textiles can be so improved.
The term cellulosic textile material as employed herein is intended to include films, yarns, fibers, filaments or threads as such or in the form of cast sheets or woven, knit, felted or non-woven fabrics, consisting of natural or regenerated cellulose or a mixture of natural and regenerated cellulose. The term is also intended to include such fabrics, films, yarns, sheets, etc., which are made up .of a major portion of cellulose or regenerated cellulose and a minor portion of non-cellulosic material.
.The invention is particularly directed to a method for improving certain of the physical or mechanical properties of an already finished cellulosic textile, as measured by the dry crease angle, tensile or tearing strength and abrasive strength of the article. By an already finished cellulosic textile we mean one which has been finished by treatment with a cross-linking chemical, such as one of the aldehydes, or witha resin-forming substance, for example a resin precondensate with the use of catalysts and in most instances with the application of elevated temperatures above about 100 C. to effect cross-linking through the aldehyde or to cure the resin-forming substance or precondensate in an on the textile.
The aforementioned finishing techniques are well-known in the art and are referred to herein as conventional. These finishes are applied to a cellulosic textile fabric, for example, to impart crease resistance and/ or dimensional stability to the goods. It is well-known to treat cellulosic textiles in swollen condition with an aldehyde in an aqueous solution containing an appreciable quantity of sulfuric acid. .This treatment imparts a good wet crease resistance. That is to say, creases formed during laundering disappear during drying. However, the dry crease resistance, that is the capability of the fabric to recover in a short time after creasing in the dry state is not appreciably improved by such aldehyde treatment. The application of a resin-forming substance, i.e., a resin precondensate, on the other hand, tends to enhance the dry crease resistance of the goods. However, both treatments have a salient disadvantage in that they very appreciably reduce the strength of the cellulosic fibers of the fabric, for example.
While the exact mechanism whereby crease resistance is improved by the aforementioned conventional finishing techniques is not completely understood, it is believed that the aldehyde treatment produces a chemical cross-linking between molecules of the cellulose or regenerated cellulose through an aldehyde bridge. In the case of resin-forming substances or resin precondensates, e.g. melamine-form-' aldehyde, it is believed that the essential reaction during condensation and curing is one of resin formation as distinguished from grafting or cross-linking with the cellulosic molecule, although of course some cross-linking and grafting may occur. It is believed that the condensed, cured resin is for the most part simply adhered to the cellulosic molecule rather than regularly and repeatedly linked chemically therewith.
In accordance with the present invention We have found that the dry crease resistance, tearing strength and abrasive strength of the textile can be very substantially improved, and in fact a highly acceptable cellulosic textile bearing the aldehyde or resin finish can be produced if the thus finished material is subjected to a critical total dose of ionizing radiation between about 10 and 5x 10 rad. While the conventional finish alone increases the crease resistance of the textile so treated, this increase is at the expense of very substantially reduced tensile or tearing and abrasive strengths of the goods. The method of the present invention not only still further increases the dry crease resistance of the textile, but very greatly enhances, for example as much as two to four times, the tearing strength and abrasion strength of the goods.
While this application is directed primarily to the improvement and rejuvenation of the aforementioned physical or mechanical properties of an already conventionally finished cellulosic textile, it is also within the scope of the present invention to carry out an aldehyde or a resinforming operation on an unfinished cellulosic textile, and then follow this finishing treatment with the application of the aforementioned dose of ionizing radiation.
The ionizing-radiation employed in the present process may be of the electromagnetic type, for example gamma or X-rays. Suitable sources of gamma include C0 fission products of U and separated isotopes such as Cs etc. Alternatively, the ionizing radiation may consist of accelerated electrons, i.e. beta particles, but of a relatively low particle energy, namely between about 0.05 and l mev., preferably between about 0.05 and 0.6 mev., which may be produced With the aid of the usual electron acceleraters, such as the cascade, Van de Graaf or linear types, or from radioactive substances such as Sr An important aspect of the present invention is the use of accelerated electrons of the aforementioned low energy values. It has been found that these low energy beta particles, that is, not above 1 mev., enable achievement of the improvements possible by the present method without any significant degradation of the cellulose or regenerated cellulose molecule. At energy levels above about 1 mev. and equivalent total dose very significant deterioration of the cellulose occurs. The importance of the use of low energy beta particles is set forth in the related application of Fritz Munzel, Serial No. 125,089, filed on even date herewith, and the information therein with respect to the importance of the use of low energy particles I ing application contain molecular groups capable of absorbing ionizing radiation energy and resonating or transe ferring excitation energy to the cellulosic molecule. The action of the sensitizers is to ultimately very greatly enhanCe the effect of ionizing radiation upon the finished textile, while also by reason of their absorptive and resonating efiiciency they serve to reduce the total dose which must be imparted to the textile to achieve the outstanding improvements attending the present process. A variety of materials suitable as sensitizers is set forth in the aforementioned copending application, and a particularly preferred material is 1,4-diphenylbenzene. The sensitizers are preferably applied to the cellulosic textile by application from aqueous media followed by squeezing off and 1 drying with the sensitized, conventionally finished textile then being ready for irradiation.
As cross-linking chemicals which may be employed in the conventional finishing above referred to, or which may be employed in the present process as a preliminary step to irradiation we intend the aldehydes, such as formaldehyde, adipic aldehyde, glyoxal, etc. The textile is treated in the swollen state in an acid medium with the aldehyde, washed out and subsequently subjected to irradiation in wet or dry condition. It is also possible to impregnate the textile with an aqueous solution of the aldehyde and an acid catalyst, subsequently heat the'impregnated textile for a short time above 100 C., wash, and then irradiate in wet or dry condition.
Where finishing is with resin-forming substances, the textile is impregnated therewith as from a dispersion or solution of the resin-forming substance which generally also contains a condensation catalyst. Following impregnation, the excess resin-forming substance is squeezed out and the impregnated fabric is then subjected to temperatures above about 100 C. for a period of time sufficient to effect curing. Typical resin-forming substances are those customarily employed in the crease-proof finishing of cellulosic textiles by conventional methods which do not employ irradiation. They are compounds which contain oxygen in the molecule or which contain sulphur in place of oxygen, as in urea and thiourea. Typical condensable or resin-forming substances include precondensates of formaldehyde with urea, thiourea, ethyleneurea and its homologues, uron, acetylene-diurene and its derivatives, dicyandiamide, melamine, phenol and its derivatives, methylolurea, methylolamines. Also suitable are ketone-aldehyde precondensates, aziridinyl compounds, triazone derivatives and diglycide ethers. Particularly useful resin-forming substances include tetrahydro-1,3-bis (methoxymethyl) -5-methyl-2( 1 -s-triazone, as described in US. Patent No. 2,373,135 or 1-carbony1-2,5-dimethoxy- 4-ethyl-triazone-2,4,6, and othersimilar triazone derivatives, as well as glycol polyacetals, for example as described in US. Patent No. 2,786,081, among other wellknown cellulosic textile finishing materials. Mixtures of two or more of these resin-forming substances can of course be employed.
The method of the present invention is applicable to textiles of all kinds, as noted above, particularly to fabrics or sheet material. The method is suited primarily for crease-proofing and imparting dimensional stability. However, it is also possible by this method to produce permanent embossing effects such as gotfering, ribbing, schreinering and moire effects as well as calendaring effects with or without friction. The method can of course be applied to textile yarns, filaments or threads. Moreover, very good crease resistance and dimensional stability can be achieved in fabrics containing relatively highly twisted yarns, such as are employed in the pro duction of voiles and marquisettes, which materials show a strong tendency to shrink. The textile materials treated in accordance with the present invention also retain a pleasant soft hand.
The instant method will be further apparent from the following typical examples which illustrate practical applications thereof and illustrate certain characteristics of the novel finished textile products.
4 Example I A cotton imitation poplin fabric was treated with the following formaldehyde solution at 34 C. for seconds:
Formaldehyde (37 percent by volume) 250 Sulfuric acid 66 B 350 Water 400 Crease Angle Tearing Abrasive in degrees Strength in g. Strength in number of revolutions Warp Fill Warp Fill Starting Material 40 45 605 595 14, 390 Section A 79 81 420 480 10, 850 Section B- 920 1, 010 38, 000
The tearing strength was determined with an Elmendorf Tearing Tester on strips 2.5 cm. wide and 16.5 cm. long. Abrasive strength was measured with an apparatus having a disc covered with a standardized wood cloth which was rotated on the surface of the fabric, and the number of revolutions noted at the time of fabric failure. Crease angles were determined as follows: 3 x 5 cm. strips of the starting and treated fabrics were folded in the warp or fill direction, respectively, and placed under a weight of 1 kg. for one hour. After removal of the weight the materials were left unweighted for 15 minutes and the crease angles thereupon measured.
Example 11 v A cotton imitation poplin fabric was treated with the formaldehyde solution of Example I at 30 C. for a period of 15 seconds, and thereupon rinsed with water in accordance with Example I, treated with ammonia, rinsed again and dried. The thus treated fabric contained 0.18% by weight formaldehyde bound to the cellulose. Two sections, A and B, were detached and Section B was treated at 20 C., in a water bath containing about 1% of 1,4-diphenylbenzene, and subsequently dried at 60-70 C. Thereupon Section B was irradiated as described in Example I. Mechanical properties of the starting fabric, finished Section A and finished-irradiation Section B were as follows:
aqueous solution of dimethylolethyleneurea containing 15 g./l. of zinc nitrate catalyst, squeezed out and predried at 60-70" C. The fabric was then heated to C. for four minutes, washed out and dried. Two sections, A and B, were detached from the thus treated fabric,
and Section B was subjected to gamma radiation from a C source to .a total dose of 7.2 10 rad. Changes in the mechanical properties of the starting fabric, finished Section A and finished-irradiated Section B were as follows:
solution containing 2 g. of a sulphonated fatty alcohol and 0.5 g. of soda in a liter of water, then rinsed with water and dried at 60 C. Two sections, A and B, were detached from the thus treated fabric and subjected to the action of accelerated electrons of a particle energy of 0.1 mev. to total doses of 10 and 2X10 rad, respectively. The properties of the unfinished starting ma- Crease An le Tearin Abrasive in degree% Strength 51g. Strengthin terial, Sect1on A and Sect1on B were as follows:
number of revolutions Warp 11111 Warp Fill 10 Crease Angle Tearing Abrasive Starting Material n 45 50 570 620 10, 380 degrees strength sect onA 117 125 310 285 11,120 revolutions Section B, Irradiated" 115 120 720 780 14, 860 Warp m Warp Fm v 15 St t v1 te 1 1 47 59 880 880 15 400 at ing 1 a t a Example 1V Section 110 10s 1, 030 1,030 20,810 SectwnB 105 100 1,110 1,110 19, 580 A cotton imitation poplin fabnc was impregnated with a 15% aqueous solution of 1-carbonyl-2,6-dimethoxy-4- ethyl-triazone-2,4,6. The solution contained no catalyst. Example VII The fabric was subsequently squeezed out, predried at 6070 C. and then heated to 140 C. for four minutes, washed out and dried. Two sections, A and B, were detached from the thus treated fabric and Section B was subjected to gamma radiation from a C0 source to a total dose of 10 rad. The mechanical properties of the starting material, finished Section A and finishedirradiated Section B were as follows:
A bleached spun rayon calico was impregnated with an aqueous solution containing per liter 100 cc. of formaldehyde (technical grade, 40%) 20 g. of zinc chloride and 20 g. of alum, squeezed out, stretched slightly over its desired finished proportions and predried at 60 C. The fabric was subsequently heated to about 130 C. for one minute, acidulated with 5 g. of 80% acetic acid and a liter of water, rinsed with coldwater, squeezed out, stretched to the desired finished proportions and dried. The thus treated fabric was exposed to a stream of accelerated electrons of a particle energy of 0.12 mev. to a total dose of 10 rad. As compared with the starting material, the formaldehyde treated-irradiated bleached spun rayon calico exhibited a substantially increased crease angle as Well as increased abrasive and tearing strengths.
It will be apparent from the foregoing examples that treatment with ionizing radiation in accordance with the present invention substantially increases the crease angle of an already conventionally finished cellulosic textile. Significant improvement will also be noted in the tearing and abrasive strengths of finished-irradiated Section B as compared with the starting or unfinished fabric.
The following Examples VI-IX further illustrate the present method employing different finishing materials and different total doses of ionizing radiation on the same fabric.
Example VI A cotton imitation poplinfabric was impregnated with an aqueous solution containing per liter of water 110 g. of a melamine-formaldehyde precondensate and 10 g. of magnesium chloride catalyst, squeezed out and dried at about 60 C. The fabric was thereupon heated to 150 C. for five minutes, washed for five minutes in a The starting fabric of Example VI was impregnated with a solution containing 300 g. of a urea-formaldehyde precondensate and 24 g. of magnesium chloride catalyst in one liter of Water, squeezed out and dried at C. Further treatment and irradiation were then carried out as described in Example V1 with the following results:
The starting fabric of Example VI was impregnated with a solution containing 120 g. of an epoxy resin based on a glycidyl ether and 6 g. of zinc fluoborate (40%) catalyst, in a liter of water, squeezed out and dried at 60 C. Further treatment and irradiation were then carried out as described in Example V1, with the following results:
Crease Angle Tearing Abrasive in degrees Strength in g. Strength in number of revolutions Warp Fill Warp Fill Starting Material 47 59 880 880 15, 400 1 Section A. 110 115 1, 230 1,100 23, 760 Section B. 110 120 1,050 1, 050 25, 880
Example IX The starting fabric of Example VI was impregnated with a solution containing g. of a glycol polyacetal of the following formula:
- 7' source to total doses of 2.5 10 7.5 and 125x10 respectively. The results were as follows:
1. A process which comprises subjecting a conventional crease resistant-finished cellulosic textile material to high energy ionizing radiation to a total dose between about 10 and 5 10 rad. to improve the crease resistance, tearing strength and abrasive strength of the crease resistance-finished textile.
2. A method as set forth in claim 1 wherein the creaseresistant finished textile is irradiated in the presence of 1,4-diphenylbenzene in contact with said textile.
3. A process as set forth in claim 1 wherein the finished textile is subjected to accelerated electron radiation of a particle energy between about 0.05 and 1 mev.
4. A process as set forth in claim 3 wherein the accelerated electron particle energy is betweenabout 0.05 and 0.6 mev.
5. A process which comprises subjecting .a conventional chemically cross-linked finished cellulosic textile material to high energy ionizing radiation to a total dose between about 10 and 5 10 rad. to improve the dry crease resistance, tearing strengthand abrasive strength of the chemically cross-linked finished textile.
6. A process as set forth in claim 5 wherein the crosslinking chemical is an aldehyde capable of cross-linking with the cellulose of the textile.
7. A process as set forth in claim 5 wherein the cross-linking chemical is a resin preoondensate.
8. A process which comprises subjecting a cellulosic textile material which has been conventionally finished with a resin-forming substance to high energy ionizing radiation to a total dose between about 10 and 5X10 rad. to improve the crease resistance, tearing strength and abrasive strength of the conventional resin-finished textile.
9. In a method of finishing a cellulosic textile material including treating the cellulosic textile in a swollen condition with an aldehyde capable of cross-linking with the cellulosic textile material in the presence of an acid re- E5 acting material, Washing and drying the aldehyde-treated textile, the improvement comprising subjecting the so treated textile to high energy ionizing radiation to a total dose between about 10 and 5 l0 rad., to improve the dry crease resistance, tearing strength and abrasive strength of the textile.
10. A method as set forth in claim 9 wherein the ionizing radiation comprises accelerated electrons of a particle energy between about 0.05 and 1 mev.
11. In a method of finishing a cellulosic textile material to improve the crease resistance thereof including treating the textile with a resin-forming substance, condensing and curing the resin, the improvement comprising subjecting the so treated textile to high energy ionizing radiation to a total dose between about 10 and 5X 10 rad. to improve the crease resistance, tearing strength and abrasion strength of the resin finished textile.
12. A method as set forth in claim 11 wherein the ionizing radiation comprises accelerated electrons of a particle energy between about 0.05 and 0.6 mev.
13. A finished cellulosic textile material produced by the process of claim 1.
14. A finished cellulosic textile material produced by the process of claim 6.
15. A finished cellulosic textile material produced by the process of claim 8.
References (Zited by the Examiner Pan, Textile Research Journal, vol. 29, 415-421 (1959). Porter, Textile Research Journal, vol. 30, N0. 7, July 1960, pps. 510-520 (pps. 510 and 518 relied-0n).
NORMAN G. TORCI-IIN, Primary Examiner.
, JULIAN S. LEVITT, Examiner.