US2054943A - Thread-treating composition - Google Patents

Description

Patented Sept. 22, 1936 UNITED. STATES THREAD-TREATING COMPOSITION Alexander B. Mould, Yonkers, N. I as- Blscklng & Chemical 00..

slg'nor to Boston- Boston, Mara, a corporation of No Drawing. Application SerlaiNo. exam 1 12 Claims.

This invention relates to improvements in materials commonlyspoken of as wax", for treating the thread used in the sewing together of shoe parts. The invention is disclosed herein as u embodied in compositions of the type known as hot waxes whichareapplied to the thread in molten condition immediately prior to the employment .of the thread in a sewing operation.

An important application of such hot waxes is in the wetting or inseaming operation, in the performance of which a chain stitch sewing machine is used to sew a welt and a shoe upper to the lip or rib of an insole to which the upper has been lasted. The invention, therefore, will be disclosed a in connection with the performance of this operation, although it will be understood that it may be employed in connection with other sewing op-. erations.

For the welting or inseaming operation the type of sewing machine forming a chain stitch is generally used. As is well known, however, chain stitch seams will ravel unless the last stitch is securely set in place and, furthermore, it is believed that tighter seams may be obtained, at least in sewing leather and the like, if each-stitch is securely held in place after the loop has been carried forward to set the stitch and while the tension on the thread is temporarily released at the start of the forward movement of the needle through the work to receive the thread with which the next loop is formed.

In the manufacture of Goodyear welt shoes it is highly desirable that the seam formed in the welting operation be tight in order that the thread of the seam may be invisible from the outside of the finished shoe and that the joint or crease between the upper and the welt may be tight and water resistant. Tightness and uniformity of this welt seam, commonly known as the inseam, is further desirable since this seam serves as a guide in several subsequent manufacturing operations, for example, welt butting, sole rounding, etc.

In the welt butting operation the ends of the welt are cut oil and skived with the possibility of cutting the stitches adjacent to each of the ends of the welt seam. It is very desirable, therefore, that such stitches be firmly sealed in in order that the ends of the weltmay not become loosened from the upper. Tightness of the welt stitches is additionally desirable for the welt butting operation since the stitches serve as a guide in this operation.

From an operating standpoint it has been found that a hot wax" composition for treating sewing thread used in the welting operation should 5 not granulate or crystallize upon standing, since the thread treating composition in this condition is dimcult to melt and to apply uniformly to the thread. Granulation" of hot waxes made from a rosin base is believed to be due to the crystallization of the abietic acid of which rosin consists in large part. It is frequently desirable also that the wax composition melt fairly readily in order that the sewing machine may be ready for use reasonably soon after the wax composition is placed in the wax pot.

In order to facilitate the sewing operation the composition in molten condition should impart slip to the thread so as to facilitate the passage thereof through the sewing machine and through the leather or other material being sewn andto avoid breakage of the thread which is maintained under tension. 0n the other hand, in order to obtain a seam of the desired tightness, the wax composition, while in partially molten condition, should be suiilciently tacky to prevent slipping of the individual stitch loops upon each other. That is to say, during the cycle of machine operations of forming each stitch there is a period, after each loop is carried forward to set the preceding stitch and as the needle starts on its forward movement, when the tension on the thread is temporarily released, and the composition on the thread should be sufficiently tacky to prevent slippage of the next previous loop at this time. -In other words, the coating on the thread while molten should facilitate, rather than ofler resistance to, the passage of the thread through the leather or other work, while at the same time the coating should be somewhat tacky when brought into contact with another portion of the coated thread.

The hot wax composition, furthermore, should harden or set fairly rapidly after the seam has In the operation known as welt beati the welt and adjacent parts are subjected to a continuous hammering action to shape the welt for outsole attaching. It is desirable that the wax composition which has been applied to the thread remain sufiiciently flexible and non-friable after solidification or hardening so as not to be removed in any substantial quantities during this operation and thereby be prevented from maintaining its protective action upon the thread.

In view of the foregoing it is an object of the invention to provide an improved thread treating composition embodying the desired characteristics hereinabove suggested, and preferably composed of ingredients which in the aggregate are relatively inexpensive.

As illustrated herein, this and other objects are accomplished by a thread treating composition consisting predominantly of rosin which is softened and plasticized with certain advantageous ingredients, for example, petrolatum and paraffin oil employed in the approximate proportions of 8 parts petrolatum to 5 parts paraffin oil. The composition, furthermore, contains a small amount of rubber, usually a fraction of 1%, which has a remarkable effect in preventing or retarding granulation of the composition, as well as greatly increasing the flexibility, and'substantially decreasing the friability, of the composition when it is in solidified form. A unique and highly advantageous feature of the composition in its preferred form is the presence of water therein, say 10%, as the dispersed phase of an emulsion, the preparation of which is assisted by the use of an emulsifying agent such as triethanolamine, theentire composition, therefore, constituting an emulsion of the water-in-oil yp An example of a hot wax thread treating composition of a yellowor golden color made in Percent Gum rosin (Grade H) 85. 2' Yellow petrolatum (softening point 44 C.) 7. '7 Paraffin oil (specific gravity 0.89) 4.8 Pine tar 1. 9 White crepe rubber 0. 1 Triethanolamine (commercial) 0.3

Water about 10% of theabove This composition may be prepared by charging the rosin, petrolatum, paraffin oil and pine tar into a steam heated kettle. Agitation of the mass is preferably commenced as soon as possible. When the rosin is melted the steam is turned off and the rubber added. The rubber is preferably added in the form of a solution comprising about 1 part by weight of rubber, 1v part rosin, and '7 parts parafiln'oil. It may be noted that paramn oil and rosin are compatible with, and are softeners for, rubber, the paraffin oil serving additionally to reduce the viscosity of the rubber and to make the rubber solution readily pourable. This rubber solution may be prepared in advance and the amounts of rosin and parafiin oil employed may be deducted from the charge to the steam jacketed kettle. After the rubber solution has been added the agitation is continued and water added, preferably to the extent of about 5 or 6% of the weight of the composition in the kettle. At the time of the addition of the water, the temperature of the material-in the kettle should softness.

not be over 212 F. and preferably is within the range of 200-212 F. Triethanolamine is preferably dissolved in the first portion of water added whereby the emulsifieation of the water in the composition is hastened. The composition may then be withdrawn from the kettle and transferred-to any suitable receiving means, such as a moving belt, where water is sprayed on the composition, thereby cooling thecomposition and at the same time increasing. the water content thereof to about 10%. The cooled composition is then preferably pulled on a candy puller, as a result of which the color of the composition is somewhat lightened and a wax-likev consistency imparted thereto, after which the composition may be cut and packed.

Just prior to the removal of the composition from the kettle, the composition may be tested to determine its degree of hardness or softness, or temper, as by a method to be described hereinafter. The composition cited above gives a temper of about 225 seconds. The exact temper of a composition may vary somewhat due to variability in the raw materials, and to assure the production of a uniform product it is sometimes desirable to withhold a portion of the petrolatum and paraffin oil until the testing of the temper, and then to add sufiicient of these ingredients to give the desired predetermined temper.

The rosin, of which the above composition consists chiefly, serves to give the composition the desired body and consistency together with the desired tackiness. It further imparts setting or hardening qualities, that is to say, it makes the composition solid when it cools off from the heated condition in which it is applied to the thread. The type of rosin given in the above specific example refers to the standards of the U. S. Department of Agriculture wherein rosin is graded by color. It may be noted that rosins of the various color grades vary somewhat in granulation of the composition, a portion of the rosin may be replaced with coumaron resin. Gum rosin is the natural resin of Southern white pine, but in so far as other natural resins of coniferous trees, and indeed synthetic resins, are the equivalents of rosin, I desire the term rosin as employed in the specification and claims to be construed to cover such equivalents.

It may be noted that wood rosin, which is made from tree stumps, has not been found satisfactory because of its extreme tendency to granulate. v

The petrolatum, which consists chiefly of petroleum hydrocarbons, serves to plasticize the rosin to some extent and to give the desired slip or lubricating quality to the composition so that the treated thread may be pulled readily through the sewing machine and through the material being sewed while the composition thereon is in molten condition. The liability to thread break-' age is thus substantially eliminated. The petrolatum may be of yellow or white color varying ordinarily in softening point from 28 to 42 0., the color of the petrolatum employed depending partly on the color desired in the final composition. The term petrolatum as employed in the The use of paramn oil, therefore, prevents the In order further to assist in retardingcondition known as "dry thread" in which all of the composition is on the outside of the thread, and'by imparting the penetrating quality, provides adesired gutty" characteristic to the thread. Additionally, the paraflin oil imparts some lubricating qualities to the composition but apparently not to the same extent as does the petrolatum. The parafllp oil preferably has a specific gravity in the neighborhood of 0.89, a

portion of 8 to 5. The use of petrolatum and paraflin oil in approximately this proportion I havev found to be particularly useful in my thread treating composition in that thereby the composition may be softened readily without, on the other hand, impairing the quick-setting characteristics thereof.

The pine tar in the above composition serves primarily to imparta desired golden color thereto.

The rubber in my improved composition serves as an inhibitor of granulation, and as a promoter of flexibility of the solidified composition. Since granulation is believed to be the crystallization of the abietic acidvof which rosin consists in large part, as stated hereinabove, a function of the rubber may be considered to be the preven- .tion of the crystallization of the abietic'acid.

In performing this function it appears likely that the rubber sets up a jell structure which slows up the forces-of crystallization. While I have found a content of about 0.1% of rubber. as in the above specific example, to be sufficient to produce the desired result,- I have employed up to about 1% of rubber with satisfactory results.

White crepe rubber is preferred for the rubber ingredient because it gives the lightest color. Moreover, white crepe rubber is softened by paraflin oil and rosin somewhat more readily than are other commercial forms of rubber, for example, smoked sheet or Para rubber, and is therefore highly suitable for the preparation of the rubber solution or suspension in which form the rubber is preferably introduced into the thread-treating composition as described hereinbefore. Generally speaking, any form of rubber may be employed which is compatible with petrolatum and paraffin oil.

The triethanolamine, which is a mild organic alkali and which I prefer to employ in my improved composition, acts as a peptizing agent and aids in the emulsiflcation of the added water to form an emulsion of the water-in-oil type in which the water constitutes the dispersed phase.

The triethanolamine additionally is believed to improve the lubrication of the thread ,by the composition so as to increase the slip or ability of the thread to pass readily through the sewing machine and through the material being sewn. When a bleaching agent is added to the composition, as in the formation of white waxes, the triethanolamine serves additionally to neutralize any excess of free mineral acid from the sodium bisulphite or other bleach. While I prefer to incorporate triethanolamine into my improved composition, in certain cases other alkalis or emulsifying agents may be employed, for example, sodium hydroxide, or the emulsifying agent may be omitted entirely while still retaining many of the advantages of my invention, although wherepossible the use of an emulsifying agent is preferable.

The presence of water in emulsified form in the composition appears to improve the action on the thread, particularly on linen thread. A thread wetted by the small amount of water present in my improved composition appears to work better than a stiff dry thread. The water, it will be noted, is present as the dispersed phase of' a water-in-oil type of emulsion, the rosin, paraflin oil, petrolatum and rubber serving as the continuous phase of the emulsion. The water in this dispersed, emulsified form is thus distributed very uniformly throughout the wax composition whereby a uniform action upon the thread is obtained and, moreover,-the water in this form is not fugitive, that is to say, is not readily removed from the composition upon standing. Thus, while the water may in certain instances be omitted, in which case the triethanolamine may also be omitted, its presence particularly in emulsified form performs a highly advantageous function.

position should melt reasonably rapidly in the wax pot on the sewing machine and should not drip oi! the thread or machine during a sewing operation. The degree of hardness or softness of the wax composition imparting these and other characteristics is termed temper. I have found it convenient to determine and control the temperof the wax composition by a float test apparatus such as employed by the American Society for Testing Materials for determining the consistency of bituminous materials (see A. S. T. M. Standards for 1927, N0. Dl39-2'7; Bulletin 1216 of the U. S. Department of Agriculture, page 55; and the Journal of Industrial and Engineering Chemistry, vol. 10, N0. 10, page 818, October 1918).

' The apparatus err. ployed in this test comprises an aluminum float and a brass collar into which the sample to be tested is placed. The central aperture in the collar is filled with the wax composition to be tested and brought to a temperature of about 5 C. after which the collar is attached to the float which is then placed in a relatively large body of water maintained at 60 C. When the wax is sufliciently softened by the water to permit the water to enter into the collar and the float, the float sinks. The time elapsed in seconds from the placing of the apparatus on the water until thewater breaks through the wax is a measure of the consistency of the material under examination. The composition cited in the above specific example gave a float test of about 225 seconds. This consistency of composition is suitable for average temperature conditions and is commercially known as being of spring or fall temper.

In some factories a somewhat harder wax commaintaining the proportion of. petrolatum to paraffln oil of about 8 to 5. Examples of such variations of the above specified composition on the dry basis for winter and summer temper are as follows:

In the above cases water is added to the extent of about 10% of the dry weight as in the firstmentioned specific example.

In general it may be said that compositions according to my invention may range in temper from about 175 to 300 seconds according to the particular use to which the composition is put, and indeed in some instances the temper may vary somewhat without these limits.

In certain cases a wax is desired which is substantially white in color. Such a composition may be obtained by omitting the pine tar mentioned in the hereinbefore-described compositions and by employing a lighter colored rosin and white petrolatum and by introducing a bleach. An example of a white wax composition of 225 seconds temper made according to my invention is given below, the percentages by weight being on the dry basis:

' Per cent Rosin (Grade WW) 87.8 White petrolatum (softening point 42' C.) 7.1 Parafiln oil (specific gravity 0.89) 4.4 White crepe rubber 0.1 Triethanolamine 0.3 Bisulphite of soda (technical) 0.3

In the above case it may be noted that the triethanolamine also performs the function of neutralizing any free mineral acid present due to the use of the bisulphite of soda bleach. In the preparation of the above composition the bleach is preferably added to the composition sufliciently early to permit the bleaching action to take place before the removal of. the composition from the kettle. The rubber solution is preferably added shortly prior to the removal of the composition from the kettle, the remainderof the preparation being the same as hereinabove described with reference to the first example; The proportions of rosin, petrolatum and paraflin oil may be varied to produce softer and harder compositions in the manner indicated above with respect to the yellow or golden wax first hereinabove described.

While I have described certain specific compositions the ingredients may be varied within reasonably wide limits to produce compositions coming within the scope of my invention and having many of the desirable characteristics contemplated by this invention. Chemical equivalents of the specific substances herein disclosed may be employed and the claims should be construed to cover such equivalents. Furthermore, additiona1 substances may in certain cases be added to the wax composition to obtain modified characteristics while still remaining within the scope of this invention. The proportions may of course be varied somewhat depending upon the particular grades and characteristics of rosin, petrolatum. and parafiin oil employed. By way of example,. the proportions of various ingredients herein disclosed may vary within the limits approximately as set forth hereinbelow to provide compositions having tempers from about 175 to 300 seconds.

- Per cent Rosin to Petrolatum 3 to 15 Paraffin oil 1 to 10 Rubber 0.1 to 1 Pine tar '3 to 3 Bleach (sodium bisulphite); 0 to 1 Emulsifying agent (triethanolamine)- 0 to 1 Water 5 to 15% of the above Having described my invention, what I claim as new and desire to secure by Letters Patent of the United States is:

1. The method of treating sewing thread which comprises applying to said thread a molten composition containing approximately 75 to 95% rosin, and small amounts of petrolatum, paraflin oil, rubber and water.

2. A thread treating composition of the hot wax type adapted to be melted and applied while in molten condition to a thread, said composition comprising an emulsion of the water-in-o'il type the continuous phase of which contains approximately '75 to 95% rosin and material to plasticize said rosin, and the dispersed phase of which comprises water.

3. A thread treating composition of the hot wax type adapted to be melted and applied while in molten condition to a thread, said composition comprising an emulsion of the water-in-oil type the continuous phase of which comprises approximately 75 to 95% rosin, 3 to 15% petrolatum, and sufiicient paraffin oil so that the ratio of petrolatum to paraflin oil is about 8 to 5 by weight, and the dispersed phase of which comprises water.

4. A thread treating composition of the hot wax type adapted to be melted and applied while in molten condition to a thread, said composition comprising an emulsion of the water-in-oil type the continuous phase of which comprises approximately 75 to 95% rosin, material to plasticize said rosin, and 0.1 to 1% rubber, and the dispersed phase of which comprises water.

5. A thread treating composition of the hot wax type adapted to be melted and applied while in molten condition to a thread, said composition comprising an emulsion of the water-in-oil type the continuous phase of which comprises approximately '75 to 95% rosin, petrolatum, paraffin oil, and rubber, and the dispersed phase of which comprises water.

6. A thread treating composition of the hot wax type adapted to be melted and applied while in molten condition to a thread, said composition comprising rosin in amount of about '75 to 95%, about 3 to 15% petrolatum, and sufiicient paraflin oil so that the ratio of petrolatum to paraffin oil is about 8 to 5 by weight, said percentages being calculated on the dry basis.

7. A thread treating composition of the hot wax type adapted to be melted and applied'while in molten condition to a thread, said composition comprising rosin in amount of about '75 to 95%,

material to plasticize said rosin, and about 0.1 to

1%. rubber, said percentages being calculated on the dry basis.

8. A thread treating composition comprising about '75 to 95% rosin, about 3 to 15% petrolatum,

suflicient paraffin oil so that the ratio of petrolatum to paraffin oil is about 8 to 5 by weight, and about 0.1 to 1% rubber, said percentages being calculated on the dry basis.

9. A thread treating composition having a temper of from 175 to 300 seconds and comprising about to 95% rosin, about 3 to 15% petrolatum, sufficient paraflin oil so that the ratio of petrolatum to paraffin oil is about 8 to 5 by weight, and about 0.1 to 1% rubber, all calculated on the dry basis, and water in the neighborhood of 5 to 15% of the weight of the abovementioned ingredients.

10. A thread treating composition having a temper of from 200 to 250 seconds and comprising about to rosin, about 5 to 12% petrolatum, sufiicient parafiin oil so that the ratio of petrolatum to paraflin oil is about 8 to 5 by weight, and about 0.1 to 1% rubber, all calculated on the dry basis, and water in the neighborhood of 5 to 15% of the weight of the above-mentioned ingredients.

'11. A composition for treating sewing thread comprising the following ingredients in approximately the following proportions by weight on the dry basis:

Per cent Rosin 75 to Petrolatum 3- to 15 Paraflin oil 1 to 10 Rubber 0.1 to 1 and water in the neighborhood of 5 to 15% of the weight of the above.

12. A composition for treating sewing thread comprising the following ingredients in approximately the following proportions byweight on and water in the neighborhood of 5 to 15% of the weight of the above.

ALEXANDER n. MACDONALD.