US 2913801 A
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United States Patent STOCKING MANUFACTURE Application November 28, 1955 Serial No. 549,533
Claims priority, application Netherlands December 2, 1954 2 Claims. (Cl. 28-74).
This invention relates to a process for the manufacture of stockings from high molecular weight synthetic linear polyamide threads delustered with titanium dioxide, which stockings are destined to be so dyed in one operation that the heel of the stockings has a darker color than the leg of the stockings. This invention also relates to stockings manufactured according to said process.
The manufacture of such stockings has been executed heretofore in various ways. According to one method, the leg and the heel of the stocking are knitted from different types of polyamides which dye differently in the same bath. It is obvious that in employing that method, the polyamide which dyes to the darkest color will be incorporated in the heel. In the dyeing of such a stocking the heel portion of the stocking acquires a darker color. With the method described, however, the effect desired in the stocking industry, viz. that the heel and the leg of the stocking shall be distinguishable in darkness but not in shade, is not obtained. Due to the difference in starting material of the threads a difference in shade is inevitably obtained.
According to another known method the leg portion and the heel portion of the stocking are made from the same type of polyamide but the threads tobe incorporated in the heel portion are pretreated so as to increase the dyeing affinity of the polyamides. This method has the disadvantage that it requires an additional treatment of the threads before the knitting operation as well as that the additional treatment takes place while the threads are wound on a spool and therefore while they are less accessible for a uniform liquid treatment.
It is also known to dye the polyamide threads destined for the heel before the knitting operation. This method has the disadvantage that on the warm molding of the knitting stocking, wrinkles will form on the boundary of the leg and the heel due to the fact that the threads of the leg have not been exposed to an elevated temperature as have the threads of the heel, viz. in the previous dyeing.
The object of the present invention is to make it possible to dye in one operation stockings made from threads of high molecular weight synthetic linear polyamides (hereinafter sometimes called simply polyamides for convenience and brevity) so that the heel or other predetermined portion or portions of the stocking will be given a darker color than the leg or other predetermined portion or portions, respectively, of the stocking.
The manner in which these and other objects and features of the invention are attained will appear more fully from the following description thereof, in which reference is made to typical and preferred procedures in order to indicate more fully the nature of the invention, but without intending to limit the invention thereby.
The process according to the present invention is characterized in that of the foot portion of the stockings at least the heel is formed from polyamide threads containing carbon black as well as titanium dioxide, the
2,913,801 Patented Nov. 24, 1959 latter being employed in the conventional delustering amounts.
With a stocking thus manufactured the heel portion is not dyed more deeply than the leg portion on dyeing in one and the same bath, but the heel portion acquires a darker color due to the presence of the carbon black. It is surprising, however, that no difference in shade occurs thereby which, as indicated above, is considered to be of great advantage in this branch of the textile industry.
Preferably a portion of 0.02-0.10% by weight of carbon black is employed in the polyamide threads con- I taining carbon black and titanium dioxide, and excellent results are obtained with a proportion of 0.05% by weight of carbon black. The titanium dioxide is employed in the conventional delustering amounts'such as from 0.22% by weight, excellent results being obtained with 0.3% TiO for multifilament yarns and 0.5% for monofil. Here and elsewhere, the ratios indicated are based on the weight of the polyamide threads.
The titanium dioxide and the carbon black are incorporated in the threads in any desired manner, the details of which form no part of the present invention.
' Preferably, however, this is done by rolling the polyamide grains destined for meltspinning according to the grid process first with the titanium dioxide and then with the carbon black.
Although reference has been made primarily to a darker colored heel portion, it should be understood that the process according to the present invention may also be applied in the manufacture of stockings of which besides the heel portion also the toes (or indeed any other predetermined portions) are to be made much darker than the leg portion.
The term carbon black includes also carbon pigments related thereto which pigments may have been subjected to an aftertreatment for deepening the black color thereof.
While a specific example of a preferred method embodying the present invention has been set forth above, it will be understood that many changes and modifications may be made in the methods of procedure without departing from the spirit of the invention. It will therefore be understood that the particular proportions and methods of operation set forth above are intended to be illustrative only, and are not intended to limit the scope of the invention.
What is claimed is:
1. A process for the manufacture of stockings from polyamide threads which comprises incorporating into polyamide about 0.22% by weight of titanium dioxide and about 0.02-0.10% by weight of carbon black, meltspinning the polyamide into threads, knitting the threads into a portion of a stocking having the other portion knitted from polyamide threads of like composition but containing no carbon black, and dyeing the stocking in one operation.
2. A process for the manufacture of stockings from polyamide threads which comprises rolling polyamide in granular form in the presence of about 0.022% by weight of titanium dioxide and about 0.02-0.10% by weight of carbon black, meltspinning the polyamide according to the grid process, knitting the threads into a portion of a stocking having the other portion knitted from polyamide threads of like composition but containing no carbon black, and dyeing the stocking in one operation.
Garothers Sept. 20, 1938 Herzog July 9, 1957