MXPA98002672A - Thread of h - Google Patents

Abstract

The present invention relates to a rubber yarn comprising, in cross section, a first rubber portion comprising a natural rubber and a second rubber portion comprising a synthetic rubber.

Description

RUBBLE THREAD Background of the Invention The invention relates to rubber threads. Rubber thread is commonly used in the number of products, including narrow stretch fabric for textile applications such as bra straps and straps with bra, for toys and for braided rope ("elastic strap"). The rubber yarn is typically composed of natural rubber, which has excellent elasticity and other desirable properties such as high elongation and is useful over a wide range of temperatures. The rubber thread has been made by cutting narrow strips of rubber from a rubber sheet, producing the yarn with a square cross section. Another method involves flowing uncoagulated fluid rubber ("latex" compound) through a small or capillary opening nozzle into a coagulant bath, eg acetic acid, washing the coagulated yarn in a water bath and drying and heat the final product with heat.

Brief Description of the Invention The invention presents a rubber thread having, in the cross section, two or more portions of rubber. A portion of hu can the second portion of rubber may be a sleeve that encloses the central core. A rubber thread with two rubber portions can have a mixture of properties, some provided by the first rubber portion and others by the second rubber portion. For example, in core / sleeve mode, the core may be composed of natural rubber, and therefore, it provides the yarn with excellent elasticity, and the sleeve may be composed of a harder synthetic rubber that is more elastic to the abrasion, fire or chemical attack because the outer portion of the thread is composed of a rubber adapted for that purpose, while also having excellent elasticity because the core is composed of natural rubber. Similarly, a two-part rubber thread with an external synthetic rubber sleeve may be preferred to the all-natural thread by customers seeking a hypoallergenic product. The properties provided by the different portions of rubber can be aesthetic. For example, with reference to the core / sleeve embodiment, a rubber yarn having a particular color can be provided by including a colorant exclusively in the outer jacket portion of the yarn. Therefore, a rubber yarn composed entirely of natural rubber may have an outer portion that includes the colorant, and an internal portion that does not include the colorant. Alternatively, the inner portion and the outer portion may include different colorants, providing a rubber thread which in the cross section has two different selected colors. The properties provided by the different portions of rubber can facilitate the manufacture of the yarn itself or of the products made from that thread. For example, if dense chloroprene rubber is included in the outer portion to improve fire retardancy, a lower density rubber may be used in the core of the yarn to offset the high specific gravity of the color and to prevent the yarn from sinking. towards the bottom of the coagulation bath. In another example, the coating can be used to adhere adjacent contact wires within a flat tape that can not be easily separated towards its component thread. The invention also features a method for making a rubber yarn having two rubber portions in the cross section. In a preferred method, the two hufe portions (in uncoagulated form) are coextruded (either coaxially or non-coaxially) to provide an uncoagulated rubber yarn composed of two portions. The rubber materials are then coagulated to provide the rubber thread of two portions. In a second preferred method, a rubber yarn including the first rubber portion is coated with the second rubber portion. The second portion of rubber when it is coated may not be coagulated, and after the coating may be in contact with a coagulating agent. Preferably, the uncoagulated rubber includes a sensitizer that promotes rapid coagulation of the coating, thus preventing its removal as the yarn passes through the process. "Rubber", as used herein, is a material that when in solid form such as a yarn may extend under environmental conditions to at least twice its resting length and, upon release of tension, may return up to 15% of its original length. "Thread" as used herein, means a fiber of any cross-sectional shape or number of continuous filaments of any average diameter from about 0.508 cm to about 0.002032 cm. "Coextrusion", as used herein, means the combination of two fluid streams within a single fluid stream. Other features and advantages of the invention will be apparent from the description of the preferred embodiments thereof and the claims.

Brief Description of the Drawings Fig. 1 is a cross-sectional view of a rubber thread having two rubber portions. Figs. 2 and 5 are illustrations of two methods for making the rubber thread.

Figs. 3 and 4 are perspective views of two assemblies for coextruding a rubber thread having two rubber portions. Figs. 6-12 are cross-sectional views of rubber threads having two or more rubber portions. Fig. 13 is a perspective view of a rubber thread having more than one rubber portion.

Description of the Preferred Modalities Referring to FIG. 1, a rubber yarn 10 includes a core 12 and a surrounding jacket 14. The core 12 is preferably composed of a natural rubber. A natural rubber core ensures that the yarn has good elasticity, particularly when the shirt 14 is not composed of natural rubber. The core preferably composes between 10% and 99%, and more preferably between 80% and 95%, of the rubber yarn 10 by weight. The sleeve 14 is preferably composed of (1) a natural or synthetic rubber that includes a colorant to give it a different color than the core 12, or (2) a synthetic rubber (with or without a colorant) that provides protection to the underlying core. Synthetic rubber can provide abrasion resistance, oil resistance, solvent resistance, ozone resistance, UV light resistance, combustion resistance, oxidation resistance or chemical resistance in general. Synthetic rubber, for example, can be resistant to solvents, oils and / or metals such as copper and manganese. Examples of preferred synthetic rubbers are acrylonitrile-butadiene (nitrile) rubbers, chloroprene rubbers and mixtures of nitrile and chloroprene. Synthetic rubbers may also include polyurethanes, butyl, polyisoprene and styrene-butadiene rubber, or mixtures thereof, and the rubber may be in the form of a true solution (in a suitable solvent), or in the form of latex a water base. The colorant used in the jacket can improve the appearance of the rubber yarn, or provide the yarn with particular cosmetic properties. For example, the shirt may include a bleach that provides a whiter-looking yarn, or a dye that glows in the dark. The colorant may also be sensitive to temperature or light, or may be selected to provide a special effect in that the jacket has a color and the core, which may also contain a colorant, has a different contrasting color. In another approach, all of the colorant that would normally be uniformly mixed throughout the yarn can be completely concentrated in the jacket for a more potent effect. The sleeve may include, for example, between 0.1% and 30% dye by weight. Frequently, it will be preferable to provide a shirt that is as thin as possible. When the shirt is composed of a synthetic rubber that has less elasticity than the natural rubber core, providing a thick shirt that can potentially adversely affect the adhesion of the shirt or the elasticity of the rubber thread. In addition, synthetic rubber can be more expensive than natural rubber. In addition, when only the jacket includes a colorant, the smaller the thickness of the jacket, the less dye used in total in the manufacture of the yarn. Preferably, the jacket composes between 1% and 90%, and more preferably between 4% and 20% of the rubber yarn by weight. There are two preferred methods for making the rubber thread 10. Referring to Fig. 2, a preferred method involves flowing a stream of uncoagulated rubber latex coextruded coaxially from a glass nozzle 18 into an acetic acid bath. 20. The rubber not coagulated in the stream coagulates and hardens in the acetic acid bath. The coagulated rubber thread is rinsed in a water bath 22, and passed into an oven in which the rubber thread is dried in the drying zone 24 and cured in the healing zone 26. The coagulation steps, rinsing, drying and curing are executed in a conventional manner. The coextruded rubber stream 16 is composed of a core of uncoagulated natural or synthetic rubber latex co-extruded with a latex sleeve of uncoagulated natural or synthetic rubber. The non-coagulated rubber latex used for the core is stored in the container 28 and the uncoated natural or synthetic rubber latex used for the jacket is stored in the container 30. The uncoagulated latex is fed by gravity into the tubes. plastic and then, may be co-extruded as illustrated in Figs. 3 and 4 • Referring to Fig. 3, a stream of uncoagulated natural or synthetic rubber flows by means of tubing from the container 30 into the tube 32 (0.396 cm ID), and in a curve flows around the outlet of the nozzle 34. The nozzle 34, which is the end of the glass tube (0.147 cm ID), is connected by plastic tubing to the container 28, and is positioned so that a stream of uncoagulated natural rubber is extruded into the center of the container. the natural or synthetic rubber stream flowing from the tube 32 to provide the coextruded rubber stream 16 in tube 38 (0.147 cm ID). Alternatively, referring to Fig. 4, the uncoagulated natural or synthetic rubber flows from the external supply container 30 through the tube 40 (0.317 cm ID) into the manifold chamber 42 (1.587 cm X 2.857 cm X 0.635 cm). He The rubber is then fed from the manifold chamber 42 through a tube (0.0792 cm of DI X 1 .270 cm long) into the single chamber 44 (0.317 cm X 0.317 cm X 1.905 cm), where the Unclogged natural or synthetic rubber stream flows to surround tube 46 (0.139 cm ID) as it approaches the exit of the camera. The tube 46 connects to the chamber 48 (0.635 cm X 4.165 cm X 2.032 cm), which in turn is connected to the container 28 through the tube 50 (0.635 cm ID). The uncoagulated natural rubber flows from the container 28 into the chamber 48. It then flows through the tube 46, and is extruded into the center of the stream of water.

Natural or synthetic rubber not coagulated to provide a rubber stream of two parts 16 (0.408 cm in diameter). The two rubber parts are co-extruded through the exit port 52 (0.139 cm in diameter), inside the acetic acid bath. All the components are made of PTFE, with the exception of tube 46, which is made of stainless steel. The flow of water currents can be controlled by adjusting the height of the containers, and by placing and adjusting thumbscrews on the plastic tubes that connect the coextrusion nozzle to the containers. The size of the core of the final yarn relative to the jacket can be controlled, for example, by adjusting the flow velocities of the respective core and sleeve rubbers.

A 37-gauge rubber thread having a black core and a white sleeve was made using the approach illustrated in FIG. 2. The core and the shirt had the following compositions: Component,% by weight. * N ucleo Cam isa Natural rubber latex ** 79.46 78.37 Alkaline solution 0.36 0.35 Sulfur 0.85 0.95 Antioxidant 1 .00 0.99 Activator of Mercaptobenzotiazoi 0.90 1 .00 Fatty acid soap 0. 1 9 0. 1 8 Inert filler 4.94 0 ZnO 1 .24 1 .22 Accelerator curing of Dithiocarbamate 0.08 007 Pigment Black 0.21 0.00 White pigment 0.00 5.85 Additional coloring 0.00 0.71 Water 10.77 1 0.26 * All components are reported on a base as received, unless otherwise indicated. ** Latex averaged 63% of total solids, reached by mixing cruciferous and reticulated rubber grids.

Alkali (for example, 45% potassium hydroxide solution) and fatty acid soap stabilizes the latex; Sulfur provides the bonds to develop the desired mechanical / physical properties; the antioxidant (for example, Wingstay L) reduces oxidative deterioration; the inert filler (for example, Kaolin Clay) increases the specific gravity of the black pigment; ZnO, mercaptobenzothiazole, and dithiocarbamate accelerates curing and improves physical properties; the black pigment gives the nucleus its black color; the white pigment (for example TiO2) and the additional dyes give the jacket its color; and the water is used to achieve the correct viscosity. Referring to Fig. 5, a second preferred method for making the rubber yarn 10 involves forming a coagulated natural rubber yarn 54, which will eventually be the core of the rubber thread 1 0, in the conventional way in an acetic acid bath to coagulate the natural rubber. The yarn is then washed in a hot water bath 56, and then passed through the immersion tank 58. The immersion tank 58 includes a natural or uncoagulated synthetic rubber that will ultimately provide the jacket of the yarn 10. Examples of natural rubbers that can be used include NC-358, 407 and 41 1, all of which are available from Ennar Latex. Examples of suitable synthetic rubbers include nitriles such as Perbunan N Latex VT from Bayer Corp., Pittsburgh, PA. If a natural rubber is used, the immersion material preferably has a pH of between 10 to 12. If a nitrile rubber is used, the immersion material preferably has a pH of between 9 and 1-1.5 and also preferably includes 0.2% to 3% of a sensitizer such as Basensol HA5 from BASF Corp., Charlotte, N.C. , in weigh. If a chloroprene rubber is used, the immersion material preferably has a pH between 9.5 and 12.0. The immersion tank preferably includes between 15% and 35% of the non-coagulated rubber by weight, and the immersion material preferably has a viscosity of between 5 cps and 40 cps. The coated wire 54 then passes over a roller 60 which has been wetted by either an uncoagulated material, hot water or a coagulating solution. The coagulant solution can be used when the coating material is natural rubber, nitrile or chloroprene. The surface tension of the solution is preferably below 40 dynes / cm; more than 28 dynes / cm is preferred. The specific gravity (concentration) of the solution can be between 1.03 and 1.16. A roller coated with hot water is preferred when the coating material is a temperature sensitive latex such as mLN372C (available from BASF). Hot water can also be used when chloroprepo mixtures are used as the coating material. The coated yarn is then immersed in the coagulation bath 62 to complete the coagulation of the latex. An example of a preferred coagulant bath consists of a calcium chloride solution (specific gravity 1.07, surface tension 32 s in water bath 64, and then passes into the standard drying / curing oven.Alternatively, the coagulant may The rubber yarn 54 is extracted from the acetic acid bath at speeds of between 6.08 meters and 18.24 meters per minute.It is preferably provided an increment of one to five per W-hundred in the case of the non-coagulated coating by nebulization or spraying. the speed by subsequent rollers to spread the yarn 10 The thickness of the coating (jacket) provided by the immersion process can be between 0.00063 cm and 0.007 cm on a yarn having a total diameter of 0.088 cm. coating is between 3% and 30% of the rubber thread by weight 15 The immersion process can also be used with the rubber thread that has been partially or totally dried and cured in an oven. After the yarn leaves the furnace, it can be sent through the immersion process (washing, coating, coagulation, washing), at a speed, for example 18.24 meters per minute. Other embodiments are within the claims. For example, the nozzle 34 in FIG. 3 and the tube 46 in FIG. 4 can be placed so that the uncoagulated natural rubber is injected into the side of the stream of uncoagulated synthetic or natural rubber to provide a rubber thread having a band (where a colorant is used in the natural uncoagulated rubber), or a rubber thread in which the natural rubber portion is located in other off-center positions within the yarn when examined in cross-section. In addition, in this embodiment and others, both portions of the yarn may be composed of synthetic rubbers. In Figs. 6-13 some alternative modalities are illustrated.

Referring to Fig. 6, a rubber thread 70 includes a core 72 and a sleeve 74, positioned in a non-concentric manner so that the core 72 provides a surface in strips. Referring to Fig. 7, a yarn 76 includes a first rubber portion 78 and a second rubber portion 80, which has a different color than the portion 78. The yarns 70 and 76 can be made by coextrusion techniques. The rubber thread may include more than two rubber portions. For example, referring to Fig. 8, the rubber thread 82 includes the core '84, the inner sleeve 86 and the outer sleeve 88, positioned in a concentric manner. Referring to Fig. 9, the yarn 90 includes a first rubber portion 92, the second rubber portion 94, and a third rubber portion 96, positioned in a non-concentric manner so that the portions 94 and 96 provide the thread with a surface in strips. Referring to Fig. 10, the rubber yarn 98 includes a first rubber portion 100, a second rubber portion 102, and a third rubber portion 104, each having a different color. The wires 82, 90 and 98 can also be made by coextrusion.

A rubber thread having three rubber portions can also be prepared by an immersion coating. For example, referring to Fig. 1 1, the rubber yarn 104 includes a rubber core 106 (made in a conventional manner), an inner rubber covering 108, and an outer rubber coating 1 10. The coatings 108 and 1 10 can be applied sequentially by dip coating methods analogous to those previously described. The roller coating can be used to prepare the rubber yarn having two or more different rubber portions. Referring to Fig. 12, the rubber yarn 1 12 includes a rubber core 1 14, prepared by conventional methods, which can be roller coated to provide a portion of rubber 1 16 covering part of the surface of the core 1 14. The portion 1 16 may have a different color from the core 1 14 to provide a strip yarn. The rubber thread may also have a core and a jacket portion that varies in thickness. For example, referring to Fig. 13, the rubber yarn 1 18 includes a core 120 and a sleeve 122 that varies regularly in thickness along the entire axial length of the yarn. The sleeve 122 reduces in thickness essentially to zero at intermittent points along the core; if the sleeve 122 has a different color than the core 120, the thread is provided with circumferential strips 124 along its exterior.

Claims (41)

# CLAIMS

1. A rubber thread comprising, in cross section, a first portion of rubber and a second portion of rubber.

2. The rubber yarn of claim 1, wherein the first portion is centrally located on the rubber thread, and the second rubber portion surrounds the first rubber portion.

3. The rubber yarn of claim 2, wherein the first rubber portion comprises a natural rubber and the second portion of rubber. 10 rubber comprises a synthetic rubber.

The rubber yarn of claim 2, wherein the second rubber portion includes a colorant that provides a color that is different from the color of the first rubber portion.

The rubber yarn of claim 2, wherein the second rubber portion is more resistant to abrasion than the first rubber portion.

6. The rubber yarn of claim 2, wherein the second rubber portion is more resistant to ultraviolet light than the first rubber portion.

7. The rubber yarn of claim 2, wherein the second portion is more resistant to solvents or other chemical agents than the first rubber portion.

The rubber thread of claim 2, wherein the second rubber portion is more fire resistant than the first portion of rubber. 25 rubber.

9. The rubber yarn of claim 2, wherein the second rubber portion is less likely to provide an allergenic response than the first rubber portion.

10. The rubber yarn of claim 2, wherein the second portion of hulecomprende between 2% and 80% of the rubber yarn by weight. eleven .

The rubber yarn of claim 2, wherein the second rubber portion comprises a nitrile rubber.

12. The rubber yarn of claim 2, wherein the second rubber portion comprises a chloroprene rubber.

13. The rubber yarn of claim 2, wherein the second rubber portion comprises a butyl rubber.

The rubber yarn of claim 2, wherein the first rubber portion and the second rubber portion comprise the same rubber material.

15. The rubber yarn of claim 13, wherein the first rubber portion includes a colorant that provides a color different from that of the second rubber portion.

16. The rubber yarn of claim 2, wherein the second rubber portion comprises a polyurethane rubber.

17. The rubber yarn of claim 2, wherein the second rubber portion comprises a styrene-butadiene rubber.

18. The rubber yarn of claim 2, wherein the second rubber portion comprises a synthetic polyisoprene rubber.

19. The rubber yarn of claim 2, wherein the second rubber portion comprises a rubber selected from the group comprising nitrile rubber, chloroprene rubber, butyl rubber, polyurethane rubber, butadiene rubber, natural rubber, polyisoprene rubber. synthetic or, a mixture that includes two or more of the previous rubbers.

20. The rubber yarn of claim 1, further comprising, in cross section, a third rubber portion in addition to the first portion and the second rubber portion.

21. A method for making a rubber yarn, comprising combining a first rubber portion and a second rubber portion to provide a rubber yarn that, in cross section, has an area comprising the first rubber portion and an area comprising the second rubber portion.

22. The method of claim 21, wherein the first rubber portion comprises a natural rubber and the second rubber portion comprises a synthetic rubber.

23. The method of claim 22, wherein the synthetic rubber is a nitrile rubber.

24. The method of claim 22, wherein the synthetic rubber is a chloroprene rubber.

25. The method of claim 22, wherein the synthetic rubber is selected from the group comprising nitrile rubber, chloroprene rubber, butyl rubber, polyurethane rubber, butadiene rubber, natural rubber., synthetic polyisoprene rubber, or a mixture that includes two or more of the above synthetic rubbers.

26. The method of claim 21, wherein the first rubber portion and the second rubber portion are combined by coextrusion in a stream comprising the first rubber portion and a stream comprising the second rubber portion.

The method of claim 26, wherein the first rubber portion and the second rubber portion are not coagulated when they are coextruded, the method further comprising coagulating the first rubber portion and the second rubber portion after coextrusion .

The method of claim 26, wherein the first rubber portion and the second rubber portion are co-extruded so that the first rubber portion is centrally located in the rubber thread enclosed by the second rubber portion.

29. The method of claim 23, wherein the first rubber portion is coated with the second rubber portion, to provide the rubber yarn.

30. The method of claim 29, wherein the second rubber portion is not coagulated when coated with the first rubber portion, the method further comprising coagulating the second rubber portion after coating.

31 The method of claim 29, wherein the coating comprises immersing the first rubber portion in a bath comprising uncoagulated rubber. #

32. The method of claim 29, wherein the bath comprises a sensitizer.

33. The method of claim 31, wherein the uncoagulated rubber is coagulated after coating.

34. The method of claim 33, wherein the coagulation comprises contacting the uncoagulated rubber with a coagulating agent.

35. The method of claim 34, wherein the coagulating agent comprises calcium nitrite.

36. The method of claim 34, wherein the coagulated rubber is contacted with the coagulating agent by passing the first coated rubber portion with the uncoagulated rubber through a bath comprising the coagulating agent.

37. The method of claim 34, wherein the uncoagulated rubber is brought into contact with the coagulating agent by passing the first portion of the rubber thread coated with the uncoagulated rubber onto a roller coated with the coagulating agent. .

38. The method of claim 21, wherein the method 20 further comprises combining a third rubber portion with the first rubber portion to provide a rubber yarn which, in cross section, has an area comprising the first rubber portion, the second rubber portion and the third rubber portion. #

39. A method for making a rubber thread of claim 21 which, when it causes contact with another similar thread, forms a permanent, strong bond between the wires.

40. A method for making a rubber yarn of claim 39 which, when a group of resulting yarns are correctly aligned, one immediately after the other, results in a flat ribbon of any desired width, which is so strongly adhered which is virtually inseparable.

41. A method for making a rubber thread, comprising 10 coextruding a first stream comprising a first portion and a second stream comprising a second portion or a portion without rubber.