NONWOVEN APPLIQUE MATERIAL
United States Patent 3762984
A nonwoven applique material for use in disposable garments worn in contact with the skin comprising a scrim with an applique adhesively bonded to the scrim. The applique is impregnated with predetermined amounts of certain acrylic adhesives and ammonium sulfamate to provide a soft material having self-extinguishing and abrasion resistance properties.
US Patent References:
Cellulosic product
Harwood - August 1959 - 2900980
Sanitary napkin
Harwood et al. - September 1959 - 2902037
Puffed cellulosic product and method of manufacture
Harwood - March 1962 - 3025199
Laminated sheet material
Harwood - January 1963 - 3072511
Process of manufacturing a web product using an adhesive plastisol
Condon et al. - March 1967 - 3307992
Cellulosic product
Harwood - August 1959 - 2900980
Sanitary napkin
Harwood et al. - September 1959 - 2902037
Puffed cellulosic product and method of manufacture
Harwood - March 1962 - 3025199
Laminated sheet material
Harwood - January 1963 - 3072511
Process of manufacturing a web product using an adhesive plastisol
Condon et al. - March 1967 - 3307992
Application Number:
05/109528
Publication Date:
10/02/1973
Filing Date:
01/25/1971
View Patent Images:
Export Citation:
Assignee:
Kimberly-Clark Corporation (Neenah, WI)
Primary Class:
Other Classes:
428/921, 442/35, 428/79
International Classes:
A41D31/02; D04H5/04; A41D31/00; D04H5/00; B32B5/12
Field of Search:
161/57,79-82,89,92,97,113-115,151 117/136,137 252/8.1
US Patent References:
| 2902395 | Absorbent wiping sheet | September 1959 | Hirschy et al. | |
| 2723212 | Flame retardant, water repellent compositions and articles treated therewith | November 1955 | Aarons et al. | |
| 2991143 | Method of water and flame proofing of cellulose fabric after dyeing | July 1961 | Rosenlind | |
| 2537323 | Unwoven fabric | January 1951 | Wurzburger |
Primary Examiner:
Lesmes, George F.
Assistant Examiner:
Bell, James J.
Parent Case Data:
This application is a continuation-in-part of my copending application Ser. No. 800,582, filed Feb. 19, 1969, now abandoned.
Claims:
I claim as my invention
1. A nonwoven applique material comprising a scrim and an applique of from about 10 to about 60 grams per square yard of said scrim, said applique being bonded to said scrim and impregnated with from about 10 to about 20% of ammonium sulfamate and from about 5 to about 12of an acrylic adhesive having a Ti of 0° C. or below, the amounts of the impregnants being based upon the untreated weight of the scrim and applique.
2. The nonwoven applique material of claim 1 wherein the applique is composed of a member selected from the group consisting of cotton, rayon, polyesters and nylon.
3. The nonwoven applique material of claim 1 wherein the scrim is composed of a material selected from the group consisting of nylon, rayon, glass and polyesters.
4. The nonwoven applique maerial of claim 1 wherein the scrim has 12 warp threads per inch and 5 fill threads per inch of a nylon multifilament yarn.
5. The nonwoven applique material of claim 1 wherein the applique is cotton and is present in an amount of about 20 grams per square yard of said scrim.
6. The nonwoven applique material of claim 1 wherein the ammonium sulfamate is present in an amount of about 14% and the acrylic adhesive has a Ti of about -14° C. and is present in an amount of about 6%.
7. The nonwoven applique material of claim 1 wherein said applique is impregnated with a minor amount of a dye.
1. A nonwoven applique material comprising a scrim and an applique of from about 10 to about 60 grams per square yard of said scrim, said applique being bonded to said scrim and impregnated with from about 10 to about 20% of ammonium sulfamate and from about 5 to about 12of an acrylic adhesive having a Ti of 0° C. or below, the amounts of the impregnants being based upon the untreated weight of the scrim and applique.
2. The nonwoven applique material of claim 1 wherein the applique is composed of a member selected from the group consisting of cotton, rayon, polyesters and nylon.
3. The nonwoven applique material of claim 1 wherein the scrim is composed of a material selected from the group consisting of nylon, rayon, glass and polyesters.
4. The nonwoven applique maerial of claim 1 wherein the scrim has 12 warp threads per inch and 5 fill threads per inch of a nylon multifilament yarn.
5. The nonwoven applique material of claim 1 wherein the applique is cotton and is present in an amount of about 20 grams per square yard of said scrim.
6. The nonwoven applique material of claim 1 wherein the ammonium sulfamate is present in an amount of about 14% and the acrylic adhesive has a Ti of about -14° C. and is present in an amount of about 6%.
7. The nonwoven applique material of claim 1 wherein said applique is impregnated with a minor amount of a dye.
Description:
DESCRIPTION OF THE INVENTION
The present invention relates generally to nonwoven materials and, more particularly, to nonwoven applique materials characterized by their improved softness, self-extinguishing and abrasion resistance properties.
Nonwoven materials are coming into widespread use as disposable garments because of their relatively low cost and simplicity of manufacture as compared with woven materials. One type of nonwoven material that may be advantageously employed is a scrim, i.e. -- a crossed thread fabric having an open mesh construction. The scrim comprises a set of spaced warp threads which extend in the machine direction, and a set of spaced fill threads which extend across the warp threads in the transverse direction. The two sets of threads are disposed in a face-to-face relation to each other, and are adhesively bonded together where the threads of one set cross the threads of the other set.
The scrim may be combined with one or more plies of cellulosic wadding bonded to the scrim to form a nonwoven-reinforced material. These materials can be fashioned into various types of outer wear, e.g., a dress or gown. However, a material of this type is not generally employed for disposable clothing worn in direction contact with the skin, i.e. -- such as panties and the like, because of insufficient softness, hand and feel.
It has been heretofore proposed to deposit a light applique on a scrim material and adhesively bond the applique to the scrim by utilizing the adhesive located on the scrim threads. Attempts to utilize a material of this type for use in disposable panties and the like have not been entirely successful. When such materials are exposed to the rubbing and abrading actions that take place in the normal usage of disposable panties or other garments worn in contact with the skin, some of the applique fibers become separated and cause a lint problem. All previous attempts to increase the resistance to abrasion have significantly decreased the softness, hand and feel of the material.
Similarly, the usage of nonwoven applique materials has been limited by their inflammability. Providing fire retardancy for the materials has concomittantly resulted in significantly diminishing the desirable aesthetic properties.
It is accordingly an object of the present invention to provide an improved nonwoven applique material that may be advantageously employed in disposable garments worn in direct contact with the skin.
Another object of the invention is to provide an improved nonwoven applique material which is characterized by improved resistance to abrasion. A related and more specific object is to provide a nonwoven applique material of the hereinbefore described type wherein the applique fibers are sufficiently bonded to the nonwoven material so that removal by the rubbing or abrading that would occur under normal conditions of usage is minimized yet the softness, hand and feel are not detrimentally affected.
A further object of the invention is to provide an improved nonwoven applique material that is treated to provide self-extinguishing characteristics with superior aesthetic characteristics. A related and more specific object is to provide such a material with self-extinguishing characteristics that cannot be readily leached out.
Yet another object of the present invention is to provide such an improved nonwoven applique material which can be readily dyed without affecting the other desirable properties of the material.
Other objects and advantages of the invention will be apparent from the following detailed description taken in conjunction with the accompanying drawings in which:
FIG. 1 is a perspective view of the nonwoven applique material of the present invention with a portion of the applique cut away to show the nonwoven material; and
FIG. 2 is a schematic view illustrating an exemplary method for forming the nonwoven applique material of the present invention.
While the invention is susceptible of various modifications and alternative forms, certain specific embodiments thereof have been shown by way of example in the drawings which will be described in detail herein. It should be understood, however, that it is not intended to limit the invention to the particular forms disclosed, but, on the contrary, the intention is to cover all modifications, equivalents and alternatives falling within the spirit and scope of the invention.
Turning now to the drawings, FIG. 1 illustrates an exemplary embodiment of the nonwoven applique material of the present invention. Thus a scrim, generally indicated at 10, includes a set of spaced warp threads 12, which extend in the longitudinal or machine direction, and a set of fill threads 14, which extend across the warp threads in the transverse direction. Since the scrim is nonwoven, the fill threads 14 are all on the same side of the warp threads 12, with the two sets of threads disposed in a face-to-face relation to each other and adhesively bonded together, as shown at 16, where the threads of one set cross the threads of the other set. In the illustrative embodiment, the softness of the material has been maximized by only applying adhesive to the warp threads 12. It should be appreciated, however, that adhesive could also be applied to the fill threads 14, if desired.
The relative openness of the scrim 10 can be varied within wide limits. However, as the number of threads in the scrim increases, the stiffness also increases and thus the aesthetic properties become less desirable. On the other hand, as the number of threads used become fewer in number, it is more difficult to effectively bond the applique to the scrim and the resistance to abrasion accordingly diminishes. It has been generally found to be suitable to employ from about 5 to about 12 threads per inch in each direction.
The denier of the threads may vary from about 10 to 100. As the denier is increased, the stiffness is increased. Employing lower deniers, on the other hand, reduces the strength of the material. The threads themselves may be formed from a variety of synthetic materials with nylon or rayon fibers being preferred. Glass and polyester fibers may also be utilized. Similarly, the individual threads can be made of either monofilament or multifilament yarn.
An applique 18 is bonded to the scrim 10. The amount of the applique can be varied from about 10 to perhaps about 60 grams per square yard of scrim. The particular amount that is employed will depend upon the properties desired and the particular material employed. Cotton and rayon are preferred because of their superior absorbency characteristics but nylon or polyesters may also be used. The lower amounts of applique result in a decrease in opacity, absorbency and softness while the higher amounts provide an increase in cost without resulting in any significantly increased properties.
In accordance with the present invention, the nonwoven applique material is treated to provide a resulting material that combines semi-permanent self-extinguishing characteristics with superior softness and abrasion resistance properties. To this end, the material is made self-extinguishing by impregnating with from about 10 to about 20 % of ammonium sulfamate, based upon the weight of the untreated nonwoven applique material. Additions below about 10 % do not result in any significant decrease in the inflammability of the applique material whereas amounts above about 20 % are not needed to provide the desired self-extinguishing and improved softness characteristics. Mono or diammonium phosphate may be subsituted for up to about 1/3 of the ammonium sulfamate.
In conjunction with the addition of the ammonium sulfamate, the nonwoven applique material is also impregnated with acrylic adhesives to improve the resistance to abrasion without unduly sacrificing the aesthetic properties and, at the same time, making the self-extinguishing characteristics semi-permanent. Thus, the applique is impregnated with an acrylic adhesive having a T i of 0 ° C. or below (i.e.--the temperature at which the torsional modulus of a film of the material is 300 kg./cm 2 ). Acrylic adhesives of this type exhibit a tolerance for the ammonium sulfamate which results in increased permanence, i.e.--minimizes leaching of the ammonium sulfamate which is normally water soluble. The amount of the acrylic adhesive should be maintained between from about 5 to about 12 % based upon the untreated weight of the nonwoven applique material. Below about 5 %, the abrasion resitance is not significantly increased by the employment of the adhesive whereas amounts above about 12 % result in a substantial decrease in absorbency, etc. Specific examples of acrylic adhesives that may be employed include "Rhoplex HA--8," manufactured by Rohm & Haas Company, Philadelphia, Pennsylvania; "Hy car 1562," "Hycar 1572," "Hycar 2671" and "Hycar 2679," manufactured by B.F. Goodrich, Akron, Ohio; and "Resyn 2813" and "Resyn 2833," manufactured by National Starch and Chemical Company, New York, New York. It is preferred to employ "Rhoplex HA--8" which is a nonionic, self cross-linking acrylic emulsion (about 46 % solids), having a specific gravity at 25° C. of 1.05 and a viscosity (Brookfield Viscometer) at 25° C. of 550 cps.
The nonwoven applique material may be readily dyed by any of the dyes that are conventionally used. For example, "Monastral blue," manufactured by E.I. DuPont de Nemours & Co., Wilmington, Delaware, can be employed. The amount of dye that will be used is dependent upon the particular dye and will vary widely, i.e.--from about 0.2 to about 10 % or more by weight, based on the untreated weight of the nonwoven applique material. In addition, other conventionally used additives may be employed. For example, a perfume or scent could be included.
As a specific example, the nonwoven applique material of the present invention can comprise the following:
scrim - 12 warp threads/inch, 30 denier regular tenacity nylon yarn; 5 fill threads/inch, 70 denier, high tenacity nylon yarn
applique - cotton 20gms./square yard of scrim
impregnants - ammonium sulfamate: about 14 % by weight, based on the weight of the untreated scrim and applique; "Rhoplex HA-8" acrylic ahdesive, having a T i of -14° C.: about 6% by weight.
FIG. 2 illustrates one method for forming the nonwoven applique material hereinbefore described. There is thus shown a scrim 20, which may be made by any of several different known methods and apparatus, one example of which is described in U.S. Pat. No. 2,841,202 to H.W. Hirschy. In forming the scrim, adhesive has generally been applied to the warp threads to provide bonding between the warp and fill threads at their crossover points. Various adhesives may be employed. Plastisols which include vinyl chloride polymers, and copolymers of vinyl chlorides with other vinyl resins, plasticized by organic phthalates, sebacates, or adipates are particularly suitable. Other adhesives that may be employed include polyvinyl acetate, acrylic resins such as the alkyl acrylates, and butadiene resins such as butadiene-styrene and butadiene acrylonitriles.
The scrim 20 is then generally passed through an oven 22 maintained at a temperature in the range of from about 200° F. to 350° F., depending upon the particular adhesive employed and as is well known.
To form the applique fibers 24 are deposited on the scrim 20 by utilizing a conventional air former, schematically shown at 26. A vacuum box 28 can be used to aid in depositing the fibers onto the scrim 20. It should be appreciated that the applique could also be formed by depositing a carded web, by using a Rando Weber, or by any other known means.
To reactivate the adhesive on the scrim threads for binding the applique thereto, the scrim 20 may be passed through a series of pre-heat rolls 30 maintained within the temperature range hereinbefore set forth in connection with the oven. The applique is then calender bonded to the scrim by rolls 32.
The thus-formed material is then treated in accordance with the present invention to improve the adhesive of the applique to the scrim and to provide self-estinguishing characteristics. In the preferred embodiment, both objectives are carried out together. To this end and as is illustrated, the nonwoven applique material 34 is passed over a turning roll 36 and into a bath 38. The bath is provided with the desired amounts of ammonium sulfamate and the acrylic binder. The bath may include a conventional defoamer to facilitate processing, if desired. Similarly, the bath may include a dye.
The simultaneous impregnation minimizes the leaching or bleeding of the ammonium sulfamate. However, since the presence of ammonium sulfamate will create an acid pH, it should be appreciated that the acrylic adhesive employed should also be stable at an acid pH. This can be avoided by separately treating the nonwoven applique material with the acrylic adhesive and the ammonium sulfamate. Becasue separate treatment detracts from the permanence of the ammonium sulfamate, it is preferred to employ an adhesive that not only has a T i of less than 0° C. but also is stable in the acid pH range.
The material 32 then passes under roll 40, and between squeeze rolls 42. In the bath, the material will generally pick up about four times its weight of liquid and the squeeze rolls remove the excess. As is conventionally known, the squeeze rolls 42 should be lubricated with the treating solution, as shown, to prevent disruption or degradation of the material. The thus-formed scrim applique material can then be wound by any conventional means.
Thus, as has been seen, the present invention provides a nonwoven applique material that may be advantageously employed for disposable garments worn in contact with the skin. The ammonium sulfamate not only provides self-extinguishing characteristics but also increases the softness, hand and feel. The specific acrylic adhesives employed provide increased abrasion resistance without significantly affecting the aesthetic properties. In addition, the acrylic adhesives exhibit a tolerance for the ammonium sulfamate that tends to minimize leaching in usage of the otherwise water-soluble sulfamate.
The present invention relates generally to nonwoven materials and, more particularly, to nonwoven applique materials characterized by their improved softness, self-extinguishing and abrasion resistance properties.
Nonwoven materials are coming into widespread use as disposable garments because of their relatively low cost and simplicity of manufacture as compared with woven materials. One type of nonwoven material that may be advantageously employed is a scrim, i.e. -- a crossed thread fabric having an open mesh construction. The scrim comprises a set of spaced warp threads which extend in the machine direction, and a set of spaced fill threads which extend across the warp threads in the transverse direction. The two sets of threads are disposed in a face-to-face relation to each other, and are adhesively bonded together where the threads of one set cross the threads of the other set.
The scrim may be combined with one or more plies of cellulosic wadding bonded to the scrim to form a nonwoven-reinforced material. These materials can be fashioned into various types of outer wear, e.g., a dress or gown. However, a material of this type is not generally employed for disposable clothing worn in direction contact with the skin, i.e. -- such as panties and the like, because of insufficient softness, hand and feel.
It has been heretofore proposed to deposit a light applique on a scrim material and adhesively bond the applique to the scrim by utilizing the adhesive located on the scrim threads. Attempts to utilize a material of this type for use in disposable panties and the like have not been entirely successful. When such materials are exposed to the rubbing and abrading actions that take place in the normal usage of disposable panties or other garments worn in contact with the skin, some of the applique fibers become separated and cause a lint problem. All previous attempts to increase the resistance to abrasion have significantly decreased the softness, hand and feel of the material.
Similarly, the usage of nonwoven applique materials has been limited by their inflammability. Providing fire retardancy for the materials has concomittantly resulted in significantly diminishing the desirable aesthetic properties.
It is accordingly an object of the present invention to provide an improved nonwoven applique material that may be advantageously employed in disposable garments worn in direct contact with the skin.
Another object of the invention is to provide an improved nonwoven applique material which is characterized by improved resistance to abrasion. A related and more specific object is to provide a nonwoven applique material of the hereinbefore described type wherein the applique fibers are sufficiently bonded to the nonwoven material so that removal by the rubbing or abrading that would occur under normal conditions of usage is minimized yet the softness, hand and feel are not detrimentally affected.
A further object of the invention is to provide an improved nonwoven applique material that is treated to provide self-extinguishing characteristics with superior aesthetic characteristics. A related and more specific object is to provide such a material with self-extinguishing characteristics that cannot be readily leached out.
Yet another object of the present invention is to provide such an improved nonwoven applique material which can be readily dyed without affecting the other desirable properties of the material.
Other objects and advantages of the invention will be apparent from the following detailed description taken in conjunction with the accompanying drawings in which:
FIG. 1 is a perspective view of the nonwoven applique material of the present invention with a portion of the applique cut away to show the nonwoven material; and
FIG. 2 is a schematic view illustrating an exemplary method for forming the nonwoven applique material of the present invention.
While the invention is susceptible of various modifications and alternative forms, certain specific embodiments thereof have been shown by way of example in the drawings which will be described in detail herein. It should be understood, however, that it is not intended to limit the invention to the particular forms disclosed, but, on the contrary, the intention is to cover all modifications, equivalents and alternatives falling within the spirit and scope of the invention.
Turning now to the drawings, FIG. 1 illustrates an exemplary embodiment of the nonwoven applique material of the present invention. Thus a scrim, generally indicated at 10, includes a set of spaced warp threads 12, which extend in the longitudinal or machine direction, and a set of fill threads 14, which extend across the warp threads in the transverse direction. Since the scrim is nonwoven, the fill threads 14 are all on the same side of the warp threads 12, with the two sets of threads disposed in a face-to-face relation to each other and adhesively bonded together, as shown at 16, where the threads of one set cross the threads of the other set. In the illustrative embodiment, the softness of the material has been maximized by only applying adhesive to the warp threads 12. It should be appreciated, however, that adhesive could also be applied to the fill threads 14, if desired.
The relative openness of the scrim 10 can be varied within wide limits. However, as the number of threads in the scrim increases, the stiffness also increases and thus the aesthetic properties become less desirable. On the other hand, as the number of threads used become fewer in number, it is more difficult to effectively bond the applique to the scrim and the resistance to abrasion accordingly diminishes. It has been generally found to be suitable to employ from about 5 to about 12 threads per inch in each direction.
The denier of the threads may vary from about 10 to 100. As the denier is increased, the stiffness is increased. Employing lower deniers, on the other hand, reduces the strength of the material. The threads themselves may be formed from a variety of synthetic materials with nylon or rayon fibers being preferred. Glass and polyester fibers may also be utilized. Similarly, the individual threads can be made of either monofilament or multifilament yarn.
An applique 18 is bonded to the scrim 10. The amount of the applique can be varied from about 10 to perhaps about 60 grams per square yard of scrim. The particular amount that is employed will depend upon the properties desired and the particular material employed. Cotton and rayon are preferred because of their superior absorbency characteristics but nylon or polyesters may also be used. The lower amounts of applique result in a decrease in opacity, absorbency and softness while the higher amounts provide an increase in cost without resulting in any significantly increased properties.
In accordance with the present invention, the nonwoven applique material is treated to provide a resulting material that combines semi-permanent self-extinguishing characteristics with superior softness and abrasion resistance properties. To this end, the material is made self-extinguishing by impregnating with from about 10 to about 20 % of ammonium sulfamate, based upon the weight of the untreated nonwoven applique material. Additions below about 10 % do not result in any significant decrease in the inflammability of the applique material whereas amounts above about 20 % are not needed to provide the desired self-extinguishing and improved softness characteristics. Mono or diammonium phosphate may be subsituted for up to about 1/3 of the ammonium sulfamate.
In conjunction with the addition of the ammonium sulfamate, the nonwoven applique material is also impregnated with acrylic adhesives to improve the resistance to abrasion without unduly sacrificing the aesthetic properties and, at the same time, making the self-extinguishing characteristics semi-permanent. Thus, the applique is impregnated with an acrylic adhesive having a T i of 0 ° C. or below (i.e.--the temperature at which the torsional modulus of a film of the material is 300 kg./cm 2 ). Acrylic adhesives of this type exhibit a tolerance for the ammonium sulfamate which results in increased permanence, i.e.--minimizes leaching of the ammonium sulfamate which is normally water soluble. The amount of the acrylic adhesive should be maintained between from about 5 to about 12 % based upon the untreated weight of the nonwoven applique material. Below about 5 %, the abrasion resitance is not significantly increased by the employment of the adhesive whereas amounts above about 12 % result in a substantial decrease in absorbency, etc. Specific examples of acrylic adhesives that may be employed include "Rhoplex HA--8," manufactured by Rohm & Haas Company, Philadelphia, Pennsylvania; "Hy car 1562," "Hycar 1572," "Hycar 2671" and "Hycar 2679," manufactured by B.F. Goodrich, Akron, Ohio; and "Resyn 2813" and "Resyn 2833," manufactured by National Starch and Chemical Company, New York, New York. It is preferred to employ "Rhoplex HA--8" which is a nonionic, self cross-linking acrylic emulsion (about 46 % solids), having a specific gravity at 25° C. of 1.05 and a viscosity (Brookfield Viscometer) at 25° C. of 550 cps.
The nonwoven applique material may be readily dyed by any of the dyes that are conventionally used. For example, "Monastral blue," manufactured by E.I. DuPont de Nemours & Co., Wilmington, Delaware, can be employed. The amount of dye that will be used is dependent upon the particular dye and will vary widely, i.e.--from about 0.2 to about 10 % or more by weight, based on the untreated weight of the nonwoven applique material. In addition, other conventionally used additives may be employed. For example, a perfume or scent could be included.
As a specific example, the nonwoven applique material of the present invention can comprise the following:
scrim - 12 warp threads/inch, 30 denier regular tenacity nylon yarn; 5 fill threads/inch, 70 denier, high tenacity nylon yarn
applique - cotton 20gms./square yard of scrim
impregnants - ammonium sulfamate: about 14 % by weight, based on the weight of the untreated scrim and applique; "Rhoplex HA-8" acrylic ahdesive, having a T i of -14° C.: about 6% by weight.
FIG. 2 illustrates one method for forming the nonwoven applique material hereinbefore described. There is thus shown a scrim 20, which may be made by any of several different known methods and apparatus, one example of which is described in U.S. Pat. No. 2,841,202 to H.W. Hirschy. In forming the scrim, adhesive has generally been applied to the warp threads to provide bonding between the warp and fill threads at their crossover points. Various adhesives may be employed. Plastisols which include vinyl chloride polymers, and copolymers of vinyl chlorides with other vinyl resins, plasticized by organic phthalates, sebacates, or adipates are particularly suitable. Other adhesives that may be employed include polyvinyl acetate, acrylic resins such as the alkyl acrylates, and butadiene resins such as butadiene-styrene and butadiene acrylonitriles.
The scrim 20 is then generally passed through an oven 22 maintained at a temperature in the range of from about 200° F. to 350° F., depending upon the particular adhesive employed and as is well known.
To form the applique fibers 24 are deposited on the scrim 20 by utilizing a conventional air former, schematically shown at 26. A vacuum box 28 can be used to aid in depositing the fibers onto the scrim 20. It should be appreciated that the applique could also be formed by depositing a carded web, by using a Rando Weber, or by any other known means.
To reactivate the adhesive on the scrim threads for binding the applique thereto, the scrim 20 may be passed through a series of pre-heat rolls 30 maintained within the temperature range hereinbefore set forth in connection with the oven. The applique is then calender bonded to the scrim by rolls 32.
The thus-formed material is then treated in accordance with the present invention to improve the adhesive of the applique to the scrim and to provide self-estinguishing characteristics. In the preferred embodiment, both objectives are carried out together. To this end and as is illustrated, the nonwoven applique material 34 is passed over a turning roll 36 and into a bath 38. The bath is provided with the desired amounts of ammonium sulfamate and the acrylic binder. The bath may include a conventional defoamer to facilitate processing, if desired. Similarly, the bath may include a dye.
The simultaneous impregnation minimizes the leaching or bleeding of the ammonium sulfamate. However, since the presence of ammonium sulfamate will create an acid pH, it should be appreciated that the acrylic adhesive employed should also be stable at an acid pH. This can be avoided by separately treating the nonwoven applique material with the acrylic adhesive and the ammonium sulfamate. Becasue separate treatment detracts from the permanence of the ammonium sulfamate, it is preferred to employ an adhesive that not only has a T i of less than 0° C. but also is stable in the acid pH range.
The material 32 then passes under roll 40, and between squeeze rolls 42. In the bath, the material will generally pick up about four times its weight of liquid and the squeeze rolls remove the excess. As is conventionally known, the squeeze rolls 42 should be lubricated with the treating solution, as shown, to prevent disruption or degradation of the material. The thus-formed scrim applique material can then be wound by any conventional means.
Thus, as has been seen, the present invention provides a nonwoven applique material that may be advantageously employed for disposable garments worn in contact with the skin. The ammonium sulfamate not only provides self-extinguishing characteristics but also increases the softness, hand and feel. The specific acrylic adhesives employed provide increased abrasion resistance without significantly affecting the aesthetic properties. In addition, the acrylic adhesives exhibit a tolerance for the ammonium sulfamate that tends to minimize leaching in usage of the otherwise water-soluble sulfamate.