US 3434875 A
Description (OCR text may contain errors)
March 25, 1969 c. SMITH ETAL 3,434,875
TENSILE LOAD AVERAGE TEXTILE FABRIC TED WITH A HIGH LECULAR WEIGHT METHYLPOLYSILOXANE ELASTOM POLYMER Filed June 29, 1964 BREAKING STRENGTH INITIAL STIFFNESS (Young's) CURVE TOUGHNESS (Area under curve) STI FFNESS ELONGATION ATTORNEYS United States Patent US. Cl. 117--139.4 2 Claims ABSTRACT OF THE DISCLOSURE There is provided a process and a product wherein a textile is coated with a high molecular weight elastomeric polymer of methylpolysiloxane from an organic vehicle containing 5 to percent of the said elastomer. The coated product is then dried and cured. The elastomer is characterized by its capability of forming a continuous tack-free film when dried and cured and has the following physical properties: 300 to 600 percent elongation, 5 to 150 grams per mil tensile strength, a Youngs modulus of 5 to 50 grams per mil thickness per percent elongation, a tuftness index of 1,000 to 50,000 grams per mil percent elongation/2 and resiliency such that the film recovers at least 70% after a 25 to 35 percent elongation. The coating is deposited essentially completely at or near the outer surface of the fibers constituting the textile and being interlocked to the textile in a noncrosslinking manner such that the coating is substantially completely dissolvable from the textile by cupric ethylene diamine. The resulting coated textile exhibits superior wrinkle resistance and wash and wear properties, good resiliency and resistance to laundering and wear along with breathability.
The present invention relates to the treatment of textile fabric. The invention is especially concerned with the preparation of improved wash/Wear and Wrinkleresistant fabric although other improved properties are also contemplated as will be hereinafter apparent.
Considerable effort has been expended, especially in recent years, towards developing Wash/Wear fabrics which can be laundered wrinkle-free without ironing. Additionally, much attention has been given towards improving the resistance of fabrics to wrinkling during wear. Some improvements have been made but despite large-scale research efforts, it has not hitherto been possible to eifectively realize the ultimate in wash/wear or wrinkle resistance without in some way undesirably effecting other essential characteristics. For example, 100% cotton fabric has been extensively treated with a Wide variety of resins and crosslinking agents and while it has been possible to thus obtain a treated product having good resiliency (i.e., ability to resist wrinkling during laundering and wear) these agents, when utilized in the amounts necessary to give the desired resiliency, tend to seriously degrade the tensile strength of the fabric. Accordingly, it is necessary to reach a compromise between strength and resiliency in the finished product depending on minimum strength requirements. This obviously means that there must be a sacrifice in wrinkle resistance and wash/Wear properties to meet strength requirements but when this is done, the resulting wrinkle resistance and wash/wear properties may very well be less than the ultimate for customer satisfaction.
The above-mentioned problems are not limited to 100% cotton fabric. Thus, for example, polyester/ cotton blends are frequently used to overcome the low strength properties of cotton fabric. Good wrinkle resistance in wear as well as laundering qualities are recognized in poly- 3,434,875 Patented Mar. 25, 1969 ester/cotton fabrics and many blend varieties have appeared on the market. However, polyester/cotton fabrics have a serious limitation in that the resiliency or wrinkle recovery properties are entirely dependent on the amount of polyester in the blend. Commercially, the blends which predominate are 65% polyester/35% cotton or 50% polyester/50% cotton and cost of the polyester, as well as comfort qualities, prohibit higher percentages of polyester. As a result, conventional polyester/cotton blends represent a compromise based on economics and comfort and other considerations but the end result is that the ultimate qualities of performance, particularly after washing and line drying are not attained. Resin is oftentimes applied to these polyester/cotton blends to improve resiliency and other properties but there is a limit on the amount of resin which can be used due to abrasion effects thus limiting the benefits attainable by means of the resin.
Another area where the ultimate in resiliency has not been satisfactorily attained is in the case of acetate/ rayon blends. Rayon is particularly lifeless: or dead, contributes nothing to hand or resiliency and may even adversely affect fabric resiliency. As a result, it is generally essential for acetate/rayon fabrics or other blends containing rayon to be resinfinished in order to achieve an acceptable degree of resiliency. A high amount of resin must be used to overcome the lack of resiliency of the rayon but this degrades the strength of the fabric and more particularly, the abrasion resistance of the rayon portion. This severely limits the possibility of obtaining maximum resiliency in blend fabrics containing rayon.
Additionally, polyester/rayon or polyester/cotton present problems inherent to crossdye effects where the polyester is dyed one color and the other component is dyed a difierent color. After resin treatment, the blend fabric shows a differential Wear with loss of the cellulosic fiber. For instance, after abrasion of a fabric where the cellulose is dyed navy and the polyester is dyed gold, the abrasion area appears predominantly gold or is frosted gold in textile terminology. In this case, the resins have degraded the strength of the cellulosic component and abrasion is a problem. The amount of resin must be carefully regulated, and is usually kept low to prevent excess frosting. Accordingly, there must be a compromise in the resiliency in order to avoid frosting.
The foregoing comments illustrate the fact that it has not been possible or practical With prior techniques to obtain ultimate resiliency in fabrics containing cotton or other cellulosic fibers. A compromise between resiliency and strength, for example, is necessary with the result that there is a sacrifice in resiliency to maintain or retain minimum strength requirements. The problem is not, however, limited to cellulosic fabrics. For example, synthetic fibers in blended or form fall short of the ultimate in wrinkle recovery performance. Thus, nylon or acetate tricot fabrics have a modest amount of resiliency but fail to keep a fresh appearance at all times. A common complaint is the fact that most lingerie is mussed in handling and does not present a new appearance over the counter to the consumer. Resin treatment does not generally help because most thermoset resins will not adhere to nylon or acetate and most thermoplastic materials do not add resilience to the natural resilience of the fiber. There is, therefore, a real need for some sort of treatment which will add to the resilience of fabrics made up of 100% nylon, acetate or various blends thereof.
There is also a serious problem in the case of glass textiles. In particular, glass fiber fabrics are of necessity finished with various thermoplastic materials which are intended to hold dye or pigment on the fiber and make the coloring washfast. In other cases, it is necessary to add various finishing materials to glass fiber fabrics to prevent damage to the glass fiber in flex abrasion. All of these finishing agents contribute to the thickness of hand but very few chemicals increase the resiliency of the glass fabric and there is usually obtained a dead hand which is without life and does not add to the esthetic qualities of the fabric.
The principal object of the present invention is to provide a novel process for treating fabric comprising natural and/ or synthetic fibers so as to eliminate the prior art problems referred to above. A more particular object of the invention is to provide means for obtaining the highest possible resilience in any type of textile fabric without seriously affecting other necessary and desirable characteristics such as strength, abrasion resistance, hand, etc.
A more specific object of the invention is to provide fabric having maximum resilience without compromising on strength or other useful and basic fabric properties. Still another specific object is the provision of fabric with unique wash/wear characteristics after laundering and outstanding resistance to wrinkling through Wear. Other objects will also be hereinafter apparent from the following detailed description of the invention.
Broadly stated, the foregoing objects are realized by applying to the textile, a silicone elastomer as hereinafter defined, preferably in organic solvent solution, followed by drying and curing, if necessary. Preferred silicone elastomers are those available as Dow Corning products XT-40025, XT40057 and 40057A. However, other silicone elastomers having the necessary characteristics as set forth below may also be effectively used. Typically useful silicone elastomers are shown in US. Patent 3,076,726, assigned to Dow-Corning and are methylpolysiloxanes.
The success of the invention is due, at least in part, to the discovery that silicone elastomers which are generally characterized by high molecular weight are essential to produce the highly resilient effects and other advantageous results of the invention. Typically, a polyester/ cotton fabric treated with Dow Corning XT40025 silicone elastomer in the manner proposed herein has a high degree of bounce and liveliness as well as improved body, water repellency, wash/wear, wrinkle resistance, and tear strength. Surprisingly, the breathability of the fabric also is not impaired by the silicone elastomer. Application of this type of elastomeric finish to a wide variety of fabrics shows generally similar improvement in resiliency and the other characteristics indicated.
Broadly stated, the term silicone elastomer as used herein is intended to mean any silicone polymer com position which can be cast on a glass plate, dried and if necessary cured, to give a continuous film having elastomeric properties and moderate strength, i.e., strength such that the film does not powder or disintegrate when rubbed lightly by the hand.
Further details on the nature of the silicone elastomer and film obtainable therefrom are given hereinafter but, for present purposes, it is sufficient to note that the silicone polymer used should possess the properties indicated. The preferred silicone elastomers for use herein are characterized by a very high molecular weight as noted above, but even lower molecular weight silicones might be used provided the composition is adequately modified or the conditions appropriately selected s as to give a continuous film having the characteristics indicated when the silicone is cast on glass, dried and, if necessary, cured. In any event, the conditions which will give this continuous film having the characteristics indicated should be used when the silicone elastomer is applied to the fabric for present purposes.
The preferred use of an organic solvent system in the practice of the invention represents a distinct departure from conventional textile processing operations. Such solvent systems are usually considered undesirable in the textile field but in the present case, these systems can be very effectively utilized to give highly unusual results. One advantage of solvent systems is that the solvent will not swell cellulosic fibers in contrast to water systems, so that rayon or cotton fabric do not shrink during the padding operation. However, it will be appreciated that elastomer emulsions or suspensions may be used in lieu of solvent systems if it is desired to do so.
It will be appreciated that, when using a solvent system, any inert solvent which will dissolve the elastomer can be used. Typical examples include hydrocarbon or chlorinated hydrocarbon solvents, e.g., mineral spirits, perchloroethylene or the like.
Any convenient method may be used to apply the elastomer to the textile. Thus, the elastomer may be applied by kiss roll, spraying, knife coating, knurled roll techniques or the like although padding is preferred. As well known in the art, padding involves dipping the fabric in the elastomer solution or pad composition and then passing the fabric through appropriate squeeze rolls to remove excess elastomer and distribute the retained polymer uniformly through the fabric. The amount of elastomer solids added to the fabric will depend on a variety of conditions, e.g., fabric construction, nature of the elastomer, etc. However, usually, the solids add-on will fall in the range of 0.1 to 30%; and preferably from 0.6 to 16%, based on the weight of the dry untreated fabric.
After padding or otherwise applying the elastomer, the fabric can be dried by air drying or by heating, e.g., in a suitably heated tenter frame. The temperature and time of drying may be selected as desired and can be widely varied as long as all solvent is removed before curing.
Curing can be accomplished at any temperature or time, but is dependent for the most part on the type of elastomer employed. The preferred time and temperature of cure also depend on the equipment available. Thus, times of the order of 30 minutes at 250 F. and 12 minutes at 425 F. may be used in loop cures. However, it may be expedient in some cases to frame cure or cure in a roller type oven by heating for from 1 minute to 10 minutes at a temperature in the range of 250 F. to 375 F.
Resilient effects are noticed most quickly when fabrics are cured at 325 to 375 F. Temperatures as low as 250 F. require times of 15 to 20 minutes or more to obtain the optimum effects. With catalyst present, some elastomers will cure without heat (room temperature) for time exposures of up to a day or more. This can be important in cases where it is impossible to apply heat or where heat may damage the base structure.
An unexpected aspect of the invention, using a silicone elastomer, is the fact that this single component alone is adequate to give the ultimate in resiliency while at the same time improving or at least maintaining at a high level other essential properties such as tensile strength, tear strength, breathability, oil repellency, wash/wear characteristics and water-repellency. In the past, it has generally been considered necessary to use a combination of materials, e.g., mixtures of polymers, high polymer resins, crosslinking agents and/ or other materials in order to obtain such a combination or properties.
The manner in which the elastomer functions to give the results described herein is not fully understood. However, it is apparent that there is no significant crosslinking between the textile and the elastomer at least in the conventional sense. Normal resin finishing materials are water soluble chemicals which are capable of crosslinking with, for example, cellulose because two or more reactive sites (difunctional) are present on the chemical. Because of the water solubility, the chemical penetrates water swollen cellulose, and is in position to crosslink when dried and cured with an appropriate catalyst. This crosslinking occurs deep inside the 'fiber, uniformly distributed within the accessible regions of the cellulose fiber and tends to cause embrittlement of the fiber. Fabric which has been treated with crosslinking chemicals will not dissolve in CED (Cupri Ethylene Diamine), a standard solvent for cellulose and a normal test for the presence of crosslinking.
In contrast, fibers treated with elastomer according to the present invention will dissolve in CED leaving behind only a slight residue which appears to be elastomer. The dissolution of the fiber in CED is an indication that no crosslinking occurs inside the fiber and shows that the action of the elastomer is completely different from normal resin crosslinking which tends to embrittle the fiber. Apparently, the original internal structure of the fiber is retained without any appreciable chemical change by operating according to the present invention thus avoiding the undesired embrittlement which occurs with crosslinking. In addition, it is well known that solvents of the type used will not swell cellulosics; hence, the elastomer has little chance to penetrate cotton for instance.
The discovery that a high degree of resiliency can be obtained on cellulosic fabric without crosslinking is highly unexpected since very little resiliency has been obtained in the past when cellulose fiber is chemically reacted with monofunctional reagents that are unable to crosslink. Thus, for example, chemicals such as monochloroacetic acid (with only one reaction site) will react with cotton but monochloroacetic does not impart resiliency as indicated by tests for wrinkle recovery. In short, crosslinking has previously been considered essential for resiliency but the present invention shows that the ultimate in resiliency can be obtained without any apparent crosslinking taking place.
Additionally, in contrast to prior techniques, it does not appear that the elastomer as used herein penetrates into the cellulosic or other fiber. Apparently, the solvent or vehicle penetrates only the outer skin of the fiber carrying sufficient elastomer into the outer skin of the fiber to cause good adhesion. The elastomer is picked up from the pad bath or other applying means and deposited in a film on the outer skin or surface of the fiber being treated. It is this outer film which appears to be important, the film acting to impart to the fiber all of the elastomeric qualities of the basic film itself. Since no crosslinking apparently takes place, the strength of the cellulosic fiber is not degraded and the basic strength of the cellulosic fiber is retained.
In addition to the film coating on each fiber, it also appears that some amount of polymer cementing or spot welding may occur between fibers. The amount of such spot welding is apparently limited because if all fibers were cemented together a stiff fabric would result. Other evidence that only limited spot welding exists is shown in the treatment of rayon high pile fabric by the method described herein. More particularly, when the high pile fabric is passed through a solution of elastomer and dried, the pile is matted down with the pad squeeze. However, only brief brushing by hand is needed to erect the pile in separate individual fibers similar to the control of untreated fabric. After curing, the pile fabric shows improved resiliency for the rayon pile compared to a control of untreated fabric.
The type of elastomer used is important to obtain optimum resiliency without a stiff hand. For instance, acrylic resins (e.g., Acryloid) have good resilient properties when cast in a film. However, when applied to fabric, desirable resiliency is not obtained. Thus, while the acrylic may be film-forming and elastomeric in nature, both of which characteristics are important for the elastomer herein, other factors prevent the acrylic film from imparting good resilience to fabric. The best results by far are obtained with silicone elastomers, but other high polymer elastomers, e.g., polyurethanes, polysulfides, or even acrylics, can be used in combination with the silastic or its equivalent.
Another property necessary in the elastomer to insure resiliency is that it must tend to lubricate the fibers and yarns in the fabric. Films which appear to be too tacky or too dry are examples of elastomers which do not impart a high degree of resilience. In particular, very thin films which are not tacky and have a slick surface, well lubricated if rubbed lightly between the fingers, impart the desired resilient characteristics. This simple test may be used to determine whether or not an elastomer can be used to impart resilience. Thus, for example, urethane elastomers are tough and elastic, yet the resilient effect on fabric is only fair. The film of the urethane elastomer is sticky to the touch indicating that fabric coated with the urethane elastomer would tend to stick together when folded. Polyvinyl alcohol films impart no resiliency to fabric and the hand is stiff, boardy, tending to crack if too much polyvinyl alcohol is used. On the other hand, silicone elastomers are slick to the touch, not sticky and when applied to fabric impart desired resiliency. Surprisingly, the properties of silicone films by themselves are not outstanding and, in fact, are only average compared to other elastomers. Nevertheless, for present purposes, the silicone elastomers are remarkably effective when applied to fabric.
The results of the invention are especially surprising in view of the fact silicone oils in emulsion form as commercially supplied, will not give equivalent results. These oils have been extensively used in the past to impart water repellency to fabric. They demonstrate a lubricating effect on fibers but the resilient effect using silicone oils alone is not sufficient to be of any commercial value. Generally, if high resiliency is desired, the silicone oils are combined with ordinary resins, the latter beng used to impart resilency while the silicone provides lubrication and softness of hand. However, the use of the resin brings about a tensile strength loss due to crosslinking between the resin and fibers.
Although the exact mechanism of the invention is not fully understood, it has been ascertained that the requirements for an effective elastomer to impart resiliency without undesirable strength loss include the following:
( 1) the agent used must be a high polymer with high molecular weight;
(2) the material must be capable of forming a continuous film when cast on glass and when applied to fabric from solution, must deposit near or on top of the surface of the fibers;
(3) the material must not be tacky, but must include some lubrication or tack-free properties;
(4) the agent must also be resilient and must show go0d recovery from elongation or deformation. The closer to recovery, the better. From 70% to 100% reeovery when tested as a film is usually satisfactory.
Best results, including the highest degree of fabric resilience, are obtained using elastomers which give films having the following characteristics when cast from solvent solution (e.g., mineral spirits) onto glass, dried and cured:
(a) moderate elongation (e.g., elongation in the range of about 3 00600% at the break);
(b) low to moderate tensile strength (representative values are 5 to grams/mil and preferably l0-50 grams/mil representing theforce required to stretch the elastomer in grams divided by thickness of the sample in mils);
(c) low to moderate initial and average stififness. The initial stiffness is the same as Youngs modulus which is determined by the stress-strain curve of the elastomer obtained by plotting tensile strength opposite percent elongation. The value is determined by the slope of the initial or elastic portion of the stress-strain curve drawn from origin tangent to curve. To make the determination, the grams tensile strength (vertical axis of the curve) is divided by thickness in mils of the sample,
then divided by percent elongation (horizontal axis of the slope), the whole result being multiplied by 100. Measurement is usually made at the 50% elongation point. A high degree of straightness in the initial portion of the stress-strain curve at a relatively steep angle, e.g., at least 60, is characteristic of a highly desirable elastomer for use herein. Average stiffness is based on the slope of the line drawn from origin to breaking point, using the same calculation as Youngs modulus. Typical values for Youngs modulus are in the range of to 50 grams/ mil thickness/ percent elongation for suitable elastomers with a preferred range of 40 grams/niil/ percent elongation. Average stiffness will vary from 1-30 grams/mil/percent elongation with a preferred range of 3 to 25. A typical elastomer stressstrain curve is shown in the figure attached hereto, the horizontal axis representing percent elongation and the vertical axis the tensile strength. Youngs modulus and average stifiness are shown by the broken lines and, as indicated, toughness is represented by the area under the curve;
Operating conditions Pad fabric at pounds padder pressure with the appropriate formulation. Air dry at room temperature or dry in oven at 200-250 F. Cure 3 minutes at 37 F. unless otherwise specified. No after wash.
The invention is illustrated, but not limited, by the following examples wherein the procedure outlined above is followed unless otherwise indicated:
EXAMPLE 1 10% Ordinary 15% Ordinary Silicone Silicone Commercial Commercial Elastomer Elastomer Resin 1 Only Resin 1 Only Formula #5 Formula #6 Only Only Crease Resistance,:
DryWarp/Fill 125/129 138/135 116/122 118/124 WetWarp/ Fill 97/113 108/118 /122 108/136 Stall-Flex Abrasion:
Warp 1, 538 406 3, 261 4, 590 Filli 2,156 090 3, 943 5, 484 Breaking Strength, Warp/Fill. 71/62 66/60 77/77 79/83 Tongue Tear, Warp/Fill 1. 7/2. 0 0. 7/1. 4 5/7/6. 7 6.2/7.7 Wash/Wear Appearance, 3 Laund. 105 Line dry 3.0 4. 5 3.0 3.0
1 The resin was Aerotex Resin 23 (American Cyanamid C0.)
((1) low to moderate toughness. Typical toughness index values for elastomers used herein fall in the range of 1,000 to 50,000 gm./mil percent elongation/2.
(e) at least 70% recovery, preferably 70l00% recovery after 2535% elongation.
The above characteristics for the elastomer used herein are important to the success of the invention and, as noted, these characteristics are found in the silicone elastomers, typically those shown in US. Patent 3,076,726. However, as noted heretofore, other high polymer elastomers may also demonstrate these characteristics when cast into films and may be useful herein. This includes such elastomers as polyurethanes of the polyether or poly- This example shows the limitation of ordinary resins which crosslink cotton cellulose chains compared to the silicone elastomer which apparently deposits as a film primarily on the outside the fiber and does not crosslink cellulose molecules.
The data indicates that 15% of the resin will impart a high degree of wash and Wear both during laundering and during wear. However, the strength of the fabric has been degraded to the point that the tear strength and abrasion, in particular, are dangerously below the safe minimum expected of this fabric. In commercial practice, the fabric finish is compromised, as noted earlier, by using less resin along with addition of softeners which tend to help abrasion and tear strength. Since the softeners do not add much to the wash and wear qualities, if anything at all, the sacrifice in wash and wear is readily apparent and a cautious balance between minimum standards for strength and maximum wash and wear must be constantly maintained.
The silicone elastomer on the other hand, by means of a single basic component does not damage the cotton. As a matter of fact, the elastomer increases the tear strength Elastomer Formula Number Percent Solids Elastomer l. 3 4 6 7 10 15 Silicone Elastomer (30% Solids in solvent as supplied) 9. 9 13. 3 20. 0 23. 4 33. 0 50. 0 Silicone Catalyst (Organic-Metallic Type) 0.3 0. 4 0.6 0.7 1. 0 1. 5 Silicone Binder (Silane Type) 2 0.5 0.5 0.5 0.5 0. 5 0.5 Acetic Acid (Glacial) 0. 5 0. 5 0. 5 0. 5 0. 5 0. 5 Solvent (Mineral Spirits) 3 88. 8 85. 3 78. 4 74. 9 65. 0 47. 5
Total Parts 100 100 100 100 100 3 Other suitable solvents include toluene, pcrchloroethyleno or other inert hydrocarbon or halohydrocarbon.
tremendously while maintaining and even increasing the tensile strength as more elastomer is added. No sacrifice in wash/wear appearance is made and the hand is soft and pleasant.
The silicone elastomer may be used to top a previously resin treated fabric which supplies a portion of the wash and wear. In the interests of economy, a lower amount of silicone elastomer can be topped on this previously resin treated fabric by solvent methods to add greatly to wash and wear qualities as illustrated by other examples herein.
An emulsion of the silicone elastomer can be added to the resin formulation (which is water soluble) to achieve superior wash and wear properties without resorting to a compromise between quality of wash and wear and physical properties because of the limitation imposed by the amount of resin.
The above results show that the addition of the elastomer greatly improved the wrinkle recovery of the resin pretreated fabric. This example also illustrates the very significant durability of the treated fabric. Thus, the wrinkle recovery of the resin pretreated decreased during 10 launderings but wrinkle recovery of the resin pretreated fabric with the elastomer on top did not decrease significantly, and in particular, the wet wrinkle recovery was retained through 10 launderings.
EXAMPLE 4 100% rayon fabric was treated with Formula 6 in the manner indicated above with 7.8% solid add-on. Comparison between the treated and untreated fabric gave the following results:
Bending Length Stifiness Crease-Resistance EXAMPLE 2 Formaldehyde pretreated 100% cotton (woven fabric) was treated in the manner indicated below using the procedure previously outlined with the following results:
The above data shows the durability of hand for the elastomer treated fabric.
Control, No Formaldehyde Test Elastomer Pretreated Formaldehyde Elastomer Pretreated Formula #5 This illustrates that the elastomer can be applied to previously resin treated cotton, in this case formaldehyde EXAMPLE 5 treated cotton. It will be noted that although the wrinkle recovery has been improved tremendously, the tensile strength and the tear strength have not been disturbed and the tear strength has been increased significantly.
Woven fabric comprising a blend of polyester/Zantrel rayon was treated as indicated with the following results showing the durability of the elastomer treatment.
Crease-Resistance, Warp+Filling Treatment Original After 3 Launderings Dry Wet Dry Wet Untreated 300 258 254 258 Elastomer Treated, Formula #5 (10.6% Add-on)-.- 313 280 308 277 EXAMPLE 3 The process of Example 2 is repeated on nitrogenous resin pretreated cotton fabric with the variations indicated: 5
Resin Pretreated EXA L 6 Resin Plus I Test pretreated A polyester/Zantrel rayon woven fabric was processed (4.2% solids and tested with the following results:
add-on) Crease Resistance Original:
Dry (Warp 'Fill'.) 207 295 Wet (Warp Fill.) 234 287 Crease Resistance, After 10 Launderings:
Dry (Warp Fill.) 192 280 Wet (Warp Fill.) 196 282 Crease Resistance, Warp Filling Tear Wash/Wear, Tensile Treatment Str. Rating Strength Original Alter Launderings Dry Wet Dry Wet Untreated 258 193 264 192 5.5 2.4 Elia stomeir igetgg u a A d fon) i 287 274 287 260 7.4 3.0 77
1 l 1 2 This illustrates the durability of the elastomer treat- This illustrates the results of measuring untreated and rnent, the increase in the wash/wear properties and the elastomer treated fabrics on the Stoll Wrinkleorneter increase in the tear strength with very little loss in tensile (Celanese wrinkle tester). Thi apparatus measures an strength. This example also illustrates very Well the l meffect similar to that of squeezing a sample of the fabric ited wrinkle recovery which the polyester/viscose blend in the hand. Although untreated .Dacron/wool is in itself has without elastomer treatment and the signlficant 1n a highly resiilent fabric, the rating obtained on the Stoll ease in the wiinkle recovery a elastomer q Wrinkleorneter is poor. 'It is noted that application of the tionally, the wrinkle recovery 1s retained after laundering. elastomer, even in small amounts raises the rating to a EXAMPLE 7 good rating.
DURABILITY OF BODY STIFFNESS AND GREASE RESISTANCE, ELAS- TOMER VS. RESIN TREATMENT, FORTREL POLYESTER/ZANTREL, FORMULA #6, 9% ADD-ON Crease Resistance Bending Length Stifiness (Warp+Fill.) Treatment Original 10 Original 10 Launderings Launderings Dry Wet Dry Wet Untreated 1. 24 1.13 256 253 192 187 Elastomer Treated, 9% Addon 1.63 1. 43 286 293 258 268 Conventional Nitrogenous Resin 2. 23 1.32 285 287 243 241 EXAMPLE 10 DACRON/COTTON, FORMULA #5, 1.8% ADD-ON Untreated Elastomer Treated Test Original 10 Original 10 Lannderings Launderings Crease Resistance, Monsanto:
Dry (Warp+Fill.) 286 265 324 315 Wet (Warp+Fill.) 250 250 314 306 Tensile Strength (Warp+Fill.). 120/77 111/76 Tear Strength (Warp+Fill.). 9.6/8.0 11.4/9.2
This illustrates the durability of the body (stiffness) This is an illustration of the effect of the elastomer and crease resistance for the elastomer treated product on Dacron/cotton. There is a significant increase in opposite a resin treatment on the same product (polywrinkle recovery after the elastomer treatment, while the ester/viscose blend). The stiffness of the fabric as inditensile strength has been held quite close to that of the cated by the bending length, particularly in the convenuntreated, and the tear test rating has been improved tional nitrogenous resin, is lost during laundering. This slightly. means that the fabric goes [from a desirable, firm hand to a very soft, raggy hand. The elastomer treated fabric EXAMPLE 11 on the other hand retains the firmness and 1t is not appre- Oil repellency ciably lost durmg launderlng. As an add1t1onal advantage, Fabric Fi qi i 2 gg 'i Product 18 Fortrel/Zantrel, Dacron/cotton. I m an O 01 S mm P Ce on e a Elastomen-A silicone elastomer having oleop'hobic EXAMPLE 8 properties (XT-40057A) was applied (similar to For- ACRYLIC/RAYON/ACETATE WOVEN FABRIC, FORMULA #4 APPLIED, 9.4% ADD-ON, BODY AND GREASE ANGLE DURABILITY Crease Resistance This further illustrates the increase and durability in mula 5) to Fortrel/Zantrel and Dacron/cotton woven wrinkle recovery resulting from the treatment of the infabrics. Highly desirable resilience, hand, body and water vention. In this particular case, there is a small loss in repellency were obtained. The elastomer finished fabric bending length stiffness which indicates that there is some also had oleophobic properties. slight loss of stiffness due to breaking of the bonds or EXAMPLE 12 spot welds that may be present on the fabric.
Woven Dacron/wool fabric was treated and tested in EXAMPLE 9 this example with the following results:
Wrinkle resistance and measure of resilience, Formulafilg Stoll/Wrinkleouneter (Celanese wrinkle tester) Untreated Silicone Test Dacron] Elastomer Fabric and treatment: Rating 3 f gf Dacron/wool 5/4800-448 untreated Poor; mussy 7 Dacron/wool S/4800-44 8 elastomer, B fit gfgffi 316 327 Formula 2 Good Wet,(Warp+Fil1.).. 265 301 Fortel/Zantrel S/47016, untreated Poor; mussy figfi fl gg gigg gfi g2 Fortrel/Zantrel 8/47016, elastomer, Tear S g (fi i g) 7.2 12.6
Bending Length, Stifiness l. 20 1. 64
Formula 6 Excellent 7 13 The above data shows the benefits in resiliency (wrinkle resistance), water repellency, body stiffness and tear strength obtained with the elastomer treatment without significantly affecting tensile strength.
The following three examples relate to the treatment of woven glass fabrics as indicated:
EXAMPLE 13 Beta fiberglassFormula -0.62% add-on 'Results.--Increased body, resilience, creasing resistance and abrasion resistance. Durability to washing.
Test Untreated E Il astomer reated Crease Resistance:
The above data show perfect or near perfect crease angles before and after laundering for the elastomer treated fabric. This is very unusual on fiberglass. Additionally, abrasion resistance is increased several times, and the treated fabric has excellent resistance to wrinkling. It should be noted that 5 launderings on a glass fabric is equivalent to washings for 2 years normal use. Excellent durability is obtained and this in itself is very unusual since fiberglass is notorious for lack of adhesion to finishes and maintaining durability in washing. Colored fabrics checked for lightfastness showed no change after 140 hours exposure.
EXAMPLE 14.-REGULAR DE FIBERGLASS (FORMULA #5) 1.6% ADD-ON It should be noted that the treated fabric has perfect dry and wet crease recovery. This is highly unusual on glass fabrics. The fabric also has perfect washability and shows a strength gain due to the treatment. The fabric can be stored in a completely wrinkled and compressed state for long periods of time, and will emerge free of wrinkles. This suggests uses such as parachutes, etc., which must recover quickly after long storage.
EXAMPLE 15.INURLED ROLL APPLICATION-COLORED FIBERGLASS-FINELY ENGRAVED LINED ROLL, FORM- ULA #5 SILICONE ELASTOMER Test Untreated Silicone Treated Tensile Strength (warp/filling) 225/225 226/232 Dry Crease Resistance (warp 314 344 Bending Length, Stiffness, ins 2. 3. 22 Stoll Wrinkleometer Lightfastness, 100 hours... 5 5
The above data show that the treatment results in tensile strength gain while imparting added crease resistance, more desirable body (stiffness), excellent wrinking resistance, and no effect on color of fabric after long light exposure.
EXAMPLE 16.-100% COTTON (WOVEN FABRIC) PRETREAT- (NIIITRO GEN OUS RESIN, FORMULA #4 APPLIED, 0
Resin Resin Test Treated Plus Only Elastomer Treated Tensile Strength, Warp/Filling 63/37 53/31 Tear Strength, Warp/Filling 4. 04/4. 1 4. 3/3. 7 Crease Resistance, (Warp Filling):
Dry, Original 233 287 Wet, Original 207 245 Dry, After 5 Launderings. 218 267 Wet, After 5 Launderings 214 252 Dry, After 5 Dry Cleanings.. 241 291 Wet, After 5 Dry Cleanings-- 208 251 Construction, Warp/Filling /60 73/61 Wash/Wear Rating 2. 5 4. 5
The above combination of the resin plus the elastomer treatment is an execellent example of how the ultimate in wash/wear properties on cotton can be reached. Not only is there a significant increase in wet and dry wrinkle recovery properties which are durable through laundering, but there is also a significant increase in the wash/wear rating. All of this is obtained at no expense in the tear strength and very slight expense in tensile strength.
EXAMPLE 17.RAYON/ACETATE, WOVEN, FORMULA #4, 5.9% ADD-ON Untreated Conventional Topped N itrogenous Test Untreated With Resin Elastomer Treatment only Tensile Strength (Warp/Fill.) /113 110/107 93/111 Tear Strength (Warp/Fill.) 5. 0/5. 7 14. 8/15. 6 8. 1/11.2 Crease Resistance, Monsanto (Warp+Fil1.):
' 256 280 306 168 205 187 230 285 271 158 203 191 265 286 299 178 168 91/39 86/36 84/35 Stoll Flex Abrasion (Warp/F1 1, 427/4, 406 1, 382/4, 208 317/590 Water Repellency, Spray Ratings:
Original 0 100 0 After 5 Lannderings.-. 0 80 After 5 Dry Cleanings 0 70 Chlorine Damage:
Tensile, Original (Warp/Fill.) 88/86 74/89 Tensile, Scorched (Warp/Fill. 87/89 41/31 Percent Tensile Loss (Warp/Fil l l/3. 5+ 45/65 A pearance after Scorching-... Wash Wear Rating 2. 5 2. 5 Air Porosity 53. 8 112. 0
l Gain. 1 Good.
4 N oticeable Scorch.
This example gives a direct comparison between (a) untreated rayon/ acetate fabric; (b) the same fabric treated with elastomer and (c) the same fabric treated with nitrogenous resin in conventional manner (including the usual softeners and hand builders). The results show the problems encountered with conventional resin treatments. Thus, for example, the tensile strength is not badly hurt, and this is characteristic of resins on rayon. (Cotton on the other hand will be degraded by this same amount of resin.) Tear strength has been improved by the addiition of conventional silicone type softeners and the wrinkle recovery obtained is quite good. However, this wrinkle recovery is obtained at the expense of stoll flex abrasion which has been significantly reduced below that of the untreated in spite of the lubricating effect of the ordinary silicone. The overall results obtainable with the elastomer treatment, however, are outstanding and this example, therefore, illustrates that, for all intents and purposes, one basic chemical can be used, according to the invention, to achieve the same properties that are ob- 20 tained in nitrogenous resins, hand builders and softeners.
16 EXAMPLE This example shows the effect of the elastomer treatment when applied to a woven Dacron/cotton lblend which has been given a commercial finish (i.e., nitrogenous resin, softeners, hand builders). Formula 4 is 1 Poor, mussy. 2 Excellent.
EXAMPLE 18.-ACRILAN/RAYON/ACETATE WOVEN FABRIC, FORMULA #4, 7% ADD-ON Conventional Test Untreated Elastomer N itrogenous Treated Resin Treatment Tensile Strength (Warp/Fill.) 118/82 123/87 104/62 Tear Strength (Warp/Fill.) 5. 2/4. 5 8. 9/7. 9 7. 7/6. 3 Crease Resistance (Warp/Fill):
Dry, Original 283 307 268 Wet, Original 204 271 222 Dry, After 5 Launderings... 281 302 280 Wet, After 5 Launderings- 211 274 233 Dry, After 5 Dry Cleanings. 282 309 284 Wet, After 5 Dry Cleanings. 187 242 201 Construction. 54/ 52/37 49/37 956/654 1, 880/1, 489 1, 347/1, 171
3. 5 5.0 3 y 62. 7 87. 6 Light Fastness, 20 hrs 4 4 Water Repellency, Spray Rating:
OriginaL. 0 100 After 5 Launderingsn 0 100 After 5 Dry Cleanings 0 70 The above example illustrates the fact that the silicone elastomer treatment of the invention does not effect air porosity of the treated fabric. Additionally, the pressed crease retention is not changed by addition of the elastomer. It might be expected that an elastomer with such wrinkle resistant properties would decrease the ability of the fabric to take a crease and retain the crease during laundering. However, the fabric was tested by making a pant leg and the elastomer treated and untreated pant legs were then washed. The rating given to both of these fabrics was 5 for the best rating that can be obtained for pressed crease retention.
The treated fabric of this example is particularly outstanding and a ladies garment made therefrom has been worn 70 hours without showing any signs of wrinkling. After 70 hours wearing, the fabrics still showed good hand and resilience of properties.
FORMULA #4, 3.7% ADD-ON.
It will be noted that while the commercially finished fabric shows good wrinkle recovery and wash/wear appearance after laundering, the fabric topped up with the elastomer showed much improved crease recovery and one full unit better wash/wear rating. This is done with only a minimum loss in tensile strength and no loss in tear strength.
N FABRIC (FORTREL/ZANTREL BLEND) Conventional Test Untreated Elastomer N itrogenous Treated Resin Treatment Tensile Strength, (Warp/ Fill.) 86/86 83/82 77/68 Tear Strength (Warp/ Fill.) 4. 0/3. 8 7. 7/8. 0 3. 8/3. 3 Crease Resistance (Warp Fill):
Wet, After 5 Launderings 238 262 228 Dry, After 5 Dry Cleanings 293 311 286 Wet, After 5 Dry Cleanings 220 270 200 stoll-Flex Abrasion (Warp/Fill.) 4,339/5,136 2, 370/5, 254 3, 364/3, 986 Bending Length, 1115.;
Original 1. 17 1. 59 1. 78 After 5 Launderings 1. 14 1. 27 1. 22 After 5 Dry Cleanings 1. 13 1. 27 1.32 Wash/Wear Rating 2. 5 3.0 4. 0 Construction 88/66 88/66 88/65 The above data further demonstrates the unique advantages of the elastomer treatment described herein.
EXAMPLE 21 This example shows the application of the invention to 1 7 a knitted fabric, namely, Arnel Triacetate/nylon tricot using Formula 3 above:
The treated fabric had a desirably high degree of resilience, slickness and muss resistance.
EXAMPLE 22 The elastomer treatment of the invention may be applied to a wide variety of fibrous structures. This includes the following, the silicone elastomer referred to being Dow XT-40025 and the method of application being the same as that outlined above.
Paper Road maps.-3 and 6% silicon elastomer produced a waterproof map.
Kraft paper and light, filmy paper products.--6% silicone elastomer, produced high resistance to water and high wet strength.
Fur or pile fabrics Plush.4 and 10% solids applied to 100% rayon gave high resilience, crush resistance, fuller hand, water and stain repellence and slicker, smoother surfaces.
Apparel coating, mohair/Dynel.10% solids, same properties as in the case of plush fabric. (Cured at 250 to protect Dynel.)
Synthetic sealskin, nylon/Orlon, imitation sealskin.-- 3 and 6% silicone elastomer produced markedly improved slickness and smoothness highly desirable in this fabric. Water repellent and stain repellent. Fabric bighly resilient.
Other materials suitable for treatment herein include, for example, webbings such as nylon seat belt webbings, nonwovens, wool blankets, sewing thread, cord, ribbon.
Staple fibers or continuous filaments of natural or synthetic materials, e.g., polyester, rayon, acrylics (Orlon), nylon, cotton, wool, etc., may also be treated with silicone elastomer in the manner indicated. Fur and pile fabrics are especially benefitted by the addition of the elastomer since the treatment gives high resiliency and also gives better crush resistance and hand as well as water and stain repellency.
EXAMPLE 23 As shown, the elastomer treated fabric had a rating only one unit below the untreated rating of 5, while ureaformaldehyde resin lowered the rating 2 units below that of the untreated. A rating of 5 is perfect and represents no frosting.
- l EXAMPLE 24 This example compares stretch recovery for untreated 18 Zantrel suiting and the same material treated with Formula 5 in the manner outlined above:
Untreated Stress Required to Stretch to Elastic Percent Elasticity in Filling at Elastic Limit Percent Stretch, 3 Lb. Load, 30 Mins Percent Stretch Recovery:
Immediately- After 15 Minutes After 2 Hours. After 24 Hours EXAMPLE 25 Two silicone elastomers (namely D'ow C-42024 and Dow C-42038) measured in the same solvent (perchloraethylene) at the same solid level (30%) (130,000 centistokes vs. 18,000 centistokes, respectively) were both ap plied in 6% solids levels on Fortrel/Zantrel and fiberglass fabrics. Both treatments gave products having essentially the same resilient property, body and surface lubricity. The effect is characteristic of many other silicone elastomers of widely varying viscosities or molecular weights provided the characteristics and properties referred to above are present.
EXAMPLE 26 Two silicone elastomers (Dow XT-40025 and combination of General Electric 88-4100 and 88-4025) were applied at 6.5% solids level each, to Fortrel/Zantrel fabrics of the same construction. Infrared analysis shows the two elastomers to be very similar in basic structure. The following comparative results were obtained:
Crease Resistance, Monsanto Warp and Filling Wet Treatment Dry Untreated... Elastomer (1) Elastomer (2) The above shows that both elastomers add materially to crease angles.
EXAMPLE 27 Regular very low viscosity silicone fluid in emulsion form (Sylmer 1108) was applied (8 solids) to a Dacron/cotton fabric and compared with the untreated fabric and the same fabric treated with silicone elastomer according to the invention. The following results were obtained:
Crease-Resistance, Monsanto (Wa.rp+Fill.)
Wash/ Wear Rating Treatment Dry Untreated Regular Silicone, 8% Solids Silicone Elastomer, 7% Solids- EXAMPLE 28 Water/oil and oil/water emulsions of solvent-dissolved silicone elastomers were prepared by conventional techniques of using appropriate emulsifiers, solvents, and high shear mixing equipment. These emulsions were applied to Dacron/cotton and fiberglass fabrics at the 10% solids level nd produced good resilience, slickness and body, as well as repellency. The water/oil system 19 produced slightly better resiliency than the oil/water system.
An oil/water emulsion of another silicon elastomer having oleophobic properties (i.e., Dow XET-40078), prepared by a colloid milling technique, also produced very desirable slickness, wrinkle resistance and body.
EXAMPLE 29 A typical silicone elastomer (i.e., Dow XT-40025) in solvent solution was com-pared to a typical silicone elastomer (i.e., Dow XT-40057A) in an emulsion system, on an equal solids level (3%) and on the same substrate (fiberglass).
FAB RIC F RTREL/ZANI REL Silicone Silicone Elastomer Elastomer Only plus Elvax Crease Resistance:
Dry, Warp, degree 138 144 Dry, Fill, degree.... 140 139 Wet Warp, degree 126 129 Wet, Fi1l., degree 126 129 Stifiness Test, inches 1. 74 1. 62
The Elvax contributed to wrinkle recovery and bulk without adding to stiffness.
The two systems show the same crease resistance and durability to washing. The emulsion tends to produce more body (stiffness) than the solvent system. Slickness is also slightly more in an emulsion than in a solvent 0 system, probably because of more surface deposition on the fabric.
As noted earlier, it is possible to use mixtures of the silicone elastomer and other polymers to modify properties as may be desired. Thus, it is possible to blend with the silicone elastomer other solvent soluble polymers or elastomers such as fluorocarbons, acrylics, urethanes (hydrophilic and hydrophobic), ethylene-vinyl type, other silicones, etc., to modify properties such as abrasion resistance, color binding, economics, body, hand,
lubricity, resilience, durability, repellency, strength, crease resistance, solidability, ad infinitum. These polymers can be applied either simultaneously with, as pretreatments before, or post-treatments after, the preferred elastomer. These polymers or elastomers can be used as protective coatings for other more fugitive or less durable finishes applied as pretreatments. They may also be used to add significantly to other pretreatments.
The use of a mixture of silicone elastomer and polyurethane in the treatment of woven glass fabric is shown Further examples showing the use of high polymers other than silicone elastomers, from a solvent system, and the results obtained thereby, are shown below:
EXAMPLE 32 Polysulfide formulation 10% solids polysulfide SH terminated (Thiokol LP-32) 1% cumene hyd-roperoxide 0.1% amine accelerator (EH-310) 88.9% toluene This formulation was applied to Dacron/cotton, resin treated cotton, nylon and glass fabric with drying and curing at room temperature and at 375 F. Body was imparted to the fabrics with only fair resilience.
EXAMPLE 3 3 A formulation was prepared comprising solvent soluble polyacrylate (Thiokol D2072 94-2) with red lead and NA-22 catalyst. The formulation was applied to Dacron/cotton and glass fabric as 10% solids in toluene,
below; curing at 300 F. Wrinkle resistance and body were EXAMPLE 30 Stoll-Flex Abrasion Crease Resistance,
Round Monsanto Treatment Rok, 11b.
load, 2 lb. Original 5 Laund.
Tension, Cycles to Dry Wet Dry Wet Failure Untreated (Warp/Fill.) 127/147 312 308 266 264 Silicone Elastomer, Urethane (3% solids each mixed together) 3,231/1,985 336 335 312 310 EXAMPLE 31 A Fortrel/Zantrel fabric was treated with a combination of a silicone elastomer and Elvax (ethylene vinyl acetate copolymer, E. I. DuPont Company).
obtained and abrasion resistance was imparted to the glass as shown below:
Cycles, stoll fiex abrasion round bar 1 lb. head Fabric treatment: load, 2 lb. tension None 1,181 Finished standard 1,572 Polyacrylate finished 26,313
21 EXAMPLE 34 The following solution was prepared:
% solids solution of urethane Gm. Urethane (Thiokol Elastothane 455) (40% solids) 25 Sulfur 0.1 Methyl ethyl ketone 74 This solution was applied to Dacron/cotton, glass and cotton fabrics with curing at 300 F. The treated products had low resilience and more body.
The superiority of the silicone elastomers having the essential characteristics outlined herein, utilized alone or in combination with other elastomers or polymers, will be apparent from the foregoing examples, including those wherein polysulfides, polyacrylates and polyurethanes, are utilized. Obviously, other elastomers than those shown above may be mixed with the silicone elastomer for use herein, e.g., any of those falling within the family of disulfones, urethanes, acrylics, sulfides and other rubbers. Additionally, various other modifications may be made in the invention as described above. For example, the elastomer treated fabric, e.g., knitted nylon goods, may be subsequently dyed to produce highly uniform dyeings with no evidence of spotted or heavily dyed areas. The elastomer finished remains even after severe dyeing conditions thus showing its surprising durability under the most rigorous conditions.
Other modifications may also be made without departing from the spirit and scope of the invention.
1. A textile fabric rendered highly resilient and having thereon a coating of a cured high molecular weight methylpolysiloxane elastomer polymer, said coating being present in a substantially noncrosslinked state with respect to said fabric and said coating being substantially completely dissolvable from the fabric by cupric ethylene diamine and said coating being disposed essentially completely at or near the outer surface of the fibers constituting said fabric, the elastomer being characterized by its high molecular weight and forming a continuous film which is tack-free, and demonstrates a resiliency such that at least recovery occurs after 25-35% elongation, 300600% elongation at break, 5-150 grams/mil tensile strength, a Youngs modulus of 5-50 grams/mil thickness/percent elongation, and a toughness 1,00050,000 grams/mil percent elongation/2.
2. The product of claim 1 wherein said elastomer composition contains at least one other elastomer selected from the group consisting of urethanes, acrylics, disulfones and sulfides.
References Cited UNITED STATES PATENTS 2,430,032 11/1947 Scott 26029.2 2,448,756 9/1948 Agens 117-161 2,950,553 8/1960 Hurwitz 117-1394 X 2,954,357 9/1960 Fekete 117-126 X 3,076,726 2/1963 Ault et al. 117-155 3,087,905 4/1963 Fluck 117-1394 X 3,179,534 4/1965 Law 117-126 X 3,240,731 3/1966 Nitzsche 117-161 WILLIAM D. MARTIN, Primary Examiner.
THEODORE G. DAVIS, Assistant Examiner.
US. Cl. X.R.