Abrasion resistant braided sleeve

This invention provides a braided tubular sleeve having increased abrasion resistance. The braided tubular sleeve according to this invention have a resilient self-conforming "springback" property which enables the sleeve to conform in close contact with the surface of substrates, such as wire or cable bundles. The increased abrasion resistance is provided by braiding in with the resilient plastic yarns about one to about twenty ends of a resilient monofilament yarn such as nylon for every two ends of a resilient engineering plastic monofilament yarn such as polyester.

FIELD OF THE INVENTION 
This invention relates to braided tubular sleeving which can be placed over 
various substrates such as wire bundles, pipes, conduits, electrical 
cables, air hoses and the like to provide certain environmental protection 
such as abrasion resistance and improved appearance. 
BACKGROUND OF THE INVENTION 
Some substrates such as electrical wire or cable are overbraided with wire 
to provide electrical shielding and other substrates such as hydraulic 
hoses are overbraided with wire or other materials to provide increased 
strength characteristics. In both instances the overbraiding can also 
provide increased abrasion resistance and durability for the product. 
However, in many instances it is impractical to overbraid such substrates 
with a desired exterior material. For example, electrical wires and cables 
are frequently installed in computer installations and particularly 
robotic installations wherein it is desirable to bundle a number of wires 
or cables together and retrofit an abrasion resistant flexible sleeving 
over the wire or cable bundle at the time of installation or some time 
after the original installation. In other circumstances it is desirable to 
protect other conduits such as air, water or other hoses from abrasion by 
retrofitting abrasion resistant sleeving over the hose at the time of 
installation or thereafter. 
Braided tubular sleeving has conventionally been used as field installed 
protective sleeving. One such product is the EXPANDO self-fitting 
protective oversleeve made by Bentley-Harris Manufacturing Co., Lionville, 
Pennsylvania. The EXPANDO sleeving is a braided tubular product made from 
a resilient engineering plastic yarn such as a monofilament polyester. The 
EXPANDO oversleeve is particularly well suited for field installation over 
wire and cable bundles or harnesses, hoses, and the like because the 
sleeving has an open weave construction which enables the braided tube to 
expand to three times it original diameter when the braided tube is 
axially compressed. When the axial compression is released the braided 
tube tends to return to its original smaller diameter due to the resilient 
nature of the engineering plastic yarn from which it is braided. This 
"springback" property gives the braided sleeving the desirable 
characteristic of being self-fitting and conforming to any size substrate 
which is larger than the original diameter of the sleeve and to any 
irregular shape of wire and cable bundle. Once installed on the substrate 
the braided sleeving tends to remain tightly conformed to the exterior of 
the substrate. Since the braided open weave construction of the 
oversleeving is very flexible, the oversleeving easily conforms to any 
bending and flexing of the substrate thus providing continual abrasion 
protection for the substrate. 
The engineering plastics from which the braided oversleeving has been made 
provides more than an adequate degree of abrasion resistance in most 
applications. However, it is desirable in some applications to have a 
higher degree of abrasion resistance. Therefore it is an objective of this 
invention to provide a braided tubular oversleeving which has increased 
abrasion resistance while retaining the springback properties desirable 
for such oversleeving. 
SUMMARY OF THE INVENTION 
This invention provides a braided tubular abrasion resistant sleeve 
comprising a resilient monofilament yarn and an abrasion resistant 
monofilament yarn present in a ratio from about one end of resilient yarn 
to two ends of abrasion resistant yarn and up to about ten ends of 
resilient yarn to one end of abrasion resistant yarn, wherein the 
resilient yarn comprises an engineering plastic having a tensile modulus 
of at least 100,000 and the abrasion resistant yarn comprises a polymeric 
material having a tensile modulus at least 50,000 less than the modulus of 
the resilient yarn. 
The preferred resilient yarn comprises polyester and the preferred abrasion 
resistant yarn comprises nylon.

DESCRIPTION OF THE INVENTION 
The braided sleeving provided by this invention can be formed on 
conventional circular braiders. The braid should not be formed so tight as 
to inhibit the flexibility of the braided sleeve or the ability of the 
sleeve to radially expand when axially compressed. In general it is 
preferred to have an open weave braid which provides maximum flexibility 
and maximum radial expansion, for example up to three times in diameter, 
to facilitate the ease of installation over various substrates, 
particularly irregular substrates such as wire bundles. Such radial 
expansion is particularly useful to enable the installer to slide the 
sleeving over connectors at the end of wire or cable bundles or fittings 
on the end of hoses then allow the sleeving to extend axially and contract 
radially to conform snugly with the wire or cable bundle or hose. 
The resilient engineering plastic yarn useful in this invention should have 
sufficient tensile modulus to provide the desired springback 
characteristic in the braided sleeving. Preferably, the fiber or yarn used 
is polyester but it will be appreciated that any of the family of plastics 
known as engineering plastics are suitable for use in the sleeves of this 
invention. By engineering plastics, it is meant that the plastic has a 
tensile modulus of greater than 100,000 and preferably greater than 
150,000 and more preferably at least 200,000. Examples of engineering 
plastics are the olefin polymers, of which some preferred olefin polymers 
are high density polyethylene, polypropylene, polybutene-1, poly 4-methyl 
pentene and fluorinated polyolefins such as 
ethylenetrifluorochloroethylene copolyers, ethylenetetrafluoroethylene 
copolymers, and vinylidene fluoride polymers, especially polyvinylidene 
fluoride, and blends thereof, for example, the fluorinated olefin blends 
as described in British patent No. 1,120,131; polyesters, for example, 
polyethylene terephthalate, polytetramethylene terephathalate for example 
those treated as described in U.S. Pat. Nos. 3,968,015; 4,073,830 and 
4,113,594; polyphenylene-oxide and -sulphide, blends of polyethylene oxide 
with polystyrene, silicone-carbonate block copolymers, polyketones, such 
as polyarylether ketones, for example, those described in U.S. Pat. Nos. 
3,953,400; 4,024,314; 4,229,564; 3,751,398; 3,914,298; 3,965,146; and 
4,111,908; polysulphones, for example, polyaryl sulphones, polyarylether 
sulphones, polyetherimides, for example those described in U.S. Pat. No. 
3,847,867, polycarbonates especially those derived from bis phenol-A, 
polyamides, especially those described in U.S. Pat. Nos. 3,551,200 and 
3,677,921, epoxy resins and blends of one or more of the above-mentioned 
polymeric materials either with each other or with other polymeric 
materials. Additional discussion of such materials is found in British 
specification No. 1,529,351. The disclosures of the above patents and 
specifications are incorporated herein by reference. 
The abrasion resistant fiber or yarn will have tensile modulus at least 
5,000 lower than the resilient yarn. Thus the abrasion resistant yarn will 
be comparatively flexible and will not interfere with the resilient nature 
of the resilient fiber or yarn which provides the springback properties 
desirable in the sleeves of the present invention. Preferably the fiber or 
yarn used as the abrasion resistant material is nylon but it will be 
appreciated that any of the family of polymeric materials having abrasion 
resistance and a low modulus relative to the resilient engineering plastic 
yarn will be suitable for use in the sleeves of this invention. By 
abrasion resistant material it is meant that the fiber or yarn be formed 
of a polymer which has sufficient abrasion resistance to enhance the 
abrasion resistance of the resilient engineering plastic yarn and have 
sufficiently low modulus to not interfere with the springback 
characteristic of the sleeve. Examples of such materials are nylon 6, 
nylon 6/6, and other nylon polymers used in their normal ambient humidity 
conditions. When the engineering plastic used as the resilient yarn in the 
sleeves of this invention has a very high modulus, other engineering 
plastics having a modulus at least 50,000 less can be used as the abrasion 
resistant yarn. For example, when the resilient engineering plastic is a 
very high modulus material such as polyethylene terephthalate then the 
abrasion resistant yarn can be a lower modulus material such as high 
density polyethylene or polypropylene. One skilled in the art following 
the disclosure of this application can select the materials desired for 
the desired sleeve properties. 
It is generally preferred but is not essential that the abrasion resistant 
yarn have a melting point at least as high as the resilient engineering 
plastic yarn. For example, when a polyester melting point in the range of 
265.degree. C. is used, it is desirable to use a nylon that melts in the 
range of 270.degree. C. 
The proportions of the resilient engineering plastic yarns and the abrasion 
resistant yarns present in the braided sleeving made according to the 
present invention may vary over a wide range provided that the resilient 
springback property of the braided sleeve is sufficient to provide 
acceptable conformance of the sleeve to the shape of the substrate desired 
to be protected. The stronger and stiffer engineering plastics used as the 
resilient yarn may be present in a lower proportion to the abrasion 
resistant yarn as compared to when the engineering plastic is a less 
resilient yarn. In general the ratio of the two types of yarns according 
to the present invention may range from about one end of resilient yarn to 
two ends of abrasion resistant yarn and up to about ten ends of resilient 
yarn to one end of abrasion resistant yarn; however is preferred that the 
ratio be between about 1:1 and 3:1 and a most preferred ratio is about 
2:1, i.e. two ends of resilient yarn to one end of abrasion resistant 
yarn. 
The resilient yarn and the abrasion resistant yarn may each be fed off of 
separate bobbins or carriers on the braider or may be combined in desired 
ratios on the carriers. For example when two ends of polyester are used 
with one end of nylon every third carrier would be nylon and the others 
would be polyester, or the two ends of polyester and one end of nylon may 
be loaded on each carrier. When fed into the braider the yarns in the 
pre-loaded ratio are braided to form the desired sleeve. The latter is the 
preferred method. 
It is generally preferred that the abrasion resistant monofilament yarn 
should have a larger diameter than the resilient yarn in order to provide 
a profile to the sleeve wherein the abrasion resistant yarn provides, in 
effect, a raised surface of the braided sleeve and the resilient yarns 
have a lower profile and are thereby protected from exterior abrasion by 
the raised abrasion resistant yarns. In general the resilient engineering 
plastic yarns will have a size in the range of 6 mils to about 15 mils and 
the abrasion resistant yarn will have a size in the range of about 8 mils 
to about 20 mils, wherein the abrasion resistant yarn is preferably at 
least 2 to 6 mils larger in diameter than the resilient yarn. It has been 
found that using polyester and nylon monofilament yarns in a ratio of two 
ends of polyester to one end of nylon the abrasion resistance was improved 
twofold over the polyester sleeve when 10 mil polyester and 12 mil nylon 
was used. However, when 10 mil polyester was used with 15 mil nylon in the 
same ratio the improvement in abrasion resistance was sixfold over the 
polyester per se sleeve. 
Referring now to the figures, a preferred embodiment of this invention can 
be illustrated. In FIG. 1 a braided tubular sleeve is illustrated wherein 
two ends of polyester engineering plastic monofilament yarns, 1, having a 
diameter of 10 mils are braided with one end of nylon monofilament yarn 
having a diameter of 15 mils. FIG. 2 better illustrates the profiled 
aspect of the larger diameter of the abrasion resistant nylon yarns, 2, 
which better protect the resilient polyester yarns 1. 
In a preferred embodiment, a half-inch I.D. sleeve is braided from two ends 
of a 10 mil monofilament polyester available under the tradename of 
"Estralyn" from Johnson Filament in Williston, Vermont, having a melt 
temperature of 265.degree. C., and one end of a 15 mil monofilament nylon 
available under the tradename "Preslyn" from Johnson Filament and having a 
melt temperature of 270.degree. C. The two ends of polyester and one end 
of nylon are loaded on each of 48 carriers on a braider and braided into 
the half-inch I.D. sleeve. Thus the final sleeve has 96 ends of 10 mil 
polyester and 48 ends of 15 mil nylon. This sleeve has outstanding 
abrasion resistance and excellent springback making it a superior product 
for wire, cable, hose, and other substrate protection.