CA2115108A1 - Polypropylene multifilament yarn and suture manufactured therefrom - Google Patents
Polypropylene multifilament yarn and suture manufactured therefromInfo
- Publication number
- CA2115108A1 CA2115108A1 CA002115108A CA2115108A CA2115108A1 CA 2115108 A1 CA2115108 A1 CA 2115108A1 CA 002115108 A CA002115108 A CA 002115108A CA 2115108 A CA2115108 A CA 2115108A CA 2115108 A1 CA2115108 A1 CA 2115108A1
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- suture
- denier
- yarn
- core
- filaments
- Prior art date
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Abstract
ABSTRACT OF THE DISCLOSURE
A polypropylene multifilament yarn of improved flexibility is manufactured under particular melt spinning conditions. The yarn is especially useful for the construction of surgical sutures.
A polypropylene multifilament yarn of improved flexibility is manufactured under particular melt spinning conditions. The yarn is especially useful for the construction of surgical sutures.
Description
2 ~ ~ 3~
1257 CIP ~;
POLYPROPYLENE MuLTIFILAMENT YARN
AND SUTURE MANUFACTURED THEREFROM
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BACXGROUND OF THE INVENTION
This invention relates to a polypropylene multifilament yarn manufactured under particular melt spinning conditions and to a surgical suture manufactured from the yarn which exhibits greater flexibility than a polypropylene suture of comparable construction manufactured - ~
from a polypropylene multifilament yarn produced under . ~ .
different melt spinning conditions. :~
Monofilament sutures fabricated from polypropylene ~ -~
: homopolymers and copolymers and from polymer blends ;~
containing polypropylene are disclosed in, among others, U.S. Patent Nos. 3,359,983, 3,630,205, 4,520,822, 4,557,264, 4,620,542, 4,621,638 and 4,911,165 and in U.K. Patent Specification No. 1,588,031 and European Patent Application No. 415,783.
: Thus, e.g., in accordance with U.S. Patent No. .`
1257 CIP ~;
POLYPROPYLENE MuLTIFILAMENT YARN
AND SUTURE MANUFACTURED THEREFROM
'' ~:'' : , :, .. ~:
BACXGROUND OF THE INVENTION
This invention relates to a polypropylene multifilament yarn manufactured under particular melt spinning conditions and to a surgical suture manufactured from the yarn which exhibits greater flexibility than a polypropylene suture of comparable construction manufactured - ~
from a polypropylene multifilament yarn produced under . ~ .
different melt spinning conditions. :~
Monofilament sutures fabricated from polypropylene ~ -~
: homopolymers and copolymers and from polymer blends ;~
containing polypropylene are disclosed in, among others, U.S. Patent Nos. 3,359,983, 3,630,205, 4,520,822, 4,557,264, 4,620,542, 4,621,638 and 4,911,165 and in U.K. Patent Specification No. 1,588,031 and European Patent Application No. 415,783.
: Thus, e.g., in accordance with U.S. Patent No. .`
3,630,205, following extrusion an isotactic polypropylene monofilament is quenched to effect its solidification and :~
drawn, or stretched, from six to seven times its original length at elevated temperature resulting in its orientation : and an increase in its tensile strength. The stretched monofilament is then collected on a spool for subsequent processing, specifically, an annealing operation which results in the shrinkage of the suture. The various conditions of the extrusion, stretching and annealing steps are indicated to be important for obtaining the desired I
2~ ~3~
polypropylene monofilament suture, one which is characterized by an ultimate elongation of from 35 to 63 percent.
The polypropylene monofilament suture manufacturing process of U.S. Patent No. 4,911,165 is said to provide a suture exhibiting improved compliance while retaining the excellent properties of prior polypropylene monofilament sutures. An increase in the draw ratio during orientation and the allowed shrinkage during annealing is credited with resulting in a monofilament suture of lower modulus at a given level of tensile strength.
As disclosed in U.S. Patent No. 5,217,485, if in the polypropylene monofilament suture manufacturing process described in U.s. Patent No. 3,630,205 the stretched monofilament is permitted to equilibrate, or "rest", prior to undergoing the annealing operation, the resulting suture will exhibit significantly improved properties such as reduced strain energy, increased knot security and reduced out-of-package set even after relatively lengthy periods of shelf storage. The strain energy of a polypropylene i~
monofilament suture is related to the amount of effort required to straighten the suture upon removal of the suture from its package such that the lower the strain energy, the lesser the effort required to straighten the suture prior to use.
Braided sutures fabricated from polypropylene multifilament yarns are known, e.g., from U.S. Patent Nos.
1 5,019,093 and 5,059,213. As disclosed in U.S. Patent No.
¦ 5,019,093, a braided suture manufactured from a variety of materials, polypropylene among them, is co~structed with a significantly greater number of sheath yarns for a given overall denier, the sheath yarns being fabricated from individual filaments of finer denier than those typical of known types of braided suture. The unique construction of -the braided suture of U.S. Patent No. 5,019,093 results in a perceptible improvement in its flexibllity and hand and ?::
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reduced chatter and drag compared with the same characteristics in a braided suture of theretofore known construction. U.S.
Patent No. 5,059,213 descrihes a suture of spiroid braid construction which can also be manufactured from various materials including polypropylene. The suture of U.S. Patent No.
5,059,213, like that of U.S. Patent No. 5,019,093, exhibits greater flexibility, better hand and less chatter and drag than other types of braided suture construction. The improved properties of the sutures of U.S. Patent Nos. 5,019,093 and 5,059,213 have largely resulted from their pattern of construction rather than from the physical properties of the yarns utilized in their manufacture.
In accordance with an embodiment of the present invention there is provided a polypropylene multifilam~nt yarn ~;`
produced by the process which comprises melt spinning an isotactic polypropylene employing an extruder equipped with a spinneret and downstream of the extruder a draw frame possessing three pairs of godets, the extruder being operated in one or more zones thereof at a temperature of from about 230 to about 270C, the pressure of the extruder being from about 1000 to about 2000 psi, the temperature of the spinneret being from about 220 to about 250C, the first pair of godets being operated at a temperature of from about 40 to about 90C and an mpm of from about 100 to about 300, the second pair of godets being operated at a temperature of from about 70 to about 130C and an mpm of from about 300 to about 1000 and the third pair of godets being operated at ambient temperature and an mpm of from about 250 to about 1000, the draw ratio of the yarn being from about 2 to about 4 and the shrinkage of the yarn being from about 5 to about 15 percent.
In accordance with another embodiment of the present invention there is provided a suture constructed with a polypropylene multifilament yarn produced by the process which comprises melt spinning an isotactic polypropylene employing an 2 ~
extruder equipped with a spinneret and downstream of the extruder a draw frame possessing three pairs o~ godets, the extruder being operated in one or more zones thereof at a temperature of from about 230 to about 270C, the pressure of the extruder being from about lO00 to about 2000 psi, the temperature of the spinneret being from about 220 to about 250C, the first pair of godets being operated at a temperature of from about 40 to about 90C
and an mpm of from about lO0 to about 300, the second pair of godets being operated at a temperature of from about 70 to about 130C and an mpm of from about 300 to about 1000 and the third pair of godets being operated at ambient temperature and an mpm of from about 250 mpm to about lO00, the draw ratio of the yarn being from about 2 to about 4 and the shrinkage of the yarn being from about 5 to about 15 percent.
Braided sutures fabricated from the foregoing polypropylene multifilament yarn exhibit significantly greater out-of-package flexibility than monofilament polypropylene sutures of the same size or braided sutures made with polypropylene multifilament yarns produced under melt spinning conditions which depart significantly in one or more respects from those recited. Thus, braided sutures incorporating the yarn of this invention can be more easily manipulated and placed at the desired wound closure site, a particularly welcome advantage where the newer laparoscopic surgical procedures are concerned.
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DESCRIPTION OF THE PREFERRED EMBODIMENTS
The multifilament yarn of this invention is .
fabricated from a polypropylene resin (isotactic index of at least about 90), preferably one which is already accepted . ~. :
for use as a suture material, e~g., a polypropylene resin having a melt flow index in g/10 min (ASTM D 1238-89) of from about 2 to about 6, preferably from about 2.1 to about 5.0 and most preferably from about 2.5 to about 4.6.
. Xnown and conventional melt spinning apparatus can be used for the production of the polypropylene multifilament yarn herein. However, the melt spinning conditions are fairly critical and for the equipment configuration described in Table I below, are as follows~
.
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TABLE I
MELT SPINNING APPARATUS AND OPERATING CONDITIONS -Apparatus Component,Range of O~erating ParameterOperatingLCondition Extruder barrel temp, zone 1 C 230-250 Extruder barrel temp, zone 2 C 230-270 Extruder barrel temp, zone 3 C 230-270 Extruder barrel pressure, psi 1000-2000 Extruder barrel melt temp., C 230-275 Pump size, cc per rev. .16-.584 Pump rpm 25-35 for size .16 pump ; -~ -~
6-10 for size .584 pump pump temp., C 220-250 Pump pressure, psi 400-1000 Pump melt temp., C 215-255 Block temp, C 220-250 ~ -Clamp temp., C 220-250 Adapter temp., C 220-250 ~ ~ ;
Candle filter, screen, microns 10-100 No. of spinneret orifices 10-200 Diameter of spinneret orifices, 5-30 .001 in. . .
Spinneret temp., C 220-250 Spinneret pressure, psi 400-1500 Spinneret melt temp., C 215-255 cc/hr output, per spinneret orifice 5-20 First pair of godets, C 40-go First pair of godets, mpm100-300 Second pair of godets, C 70-130 Second pair of godets, mpm300-1000 Draw (stretch) ratio 2-4 Third pair of godets, C ambient -Third pair of godets, mpm250-1000 Shrinkage (relaxation), percent 5-15 ~ 2 ~ ~ ~3 3~
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Properties of the individual polypropylene filaments and the yarns incorporating the filaments are ;~
advantaqeouslY as set forth in Table II below~
: ' ' , ' `
TABLE II ~ , PROPERTIESQ F INDIVIDUAL FILAMENTS AND YARNS
More Broad Preferred Preferred ` ;~
Ranqe Range Ranqe Denier per Filament 0.2-6 0.6-3 0.8-2.5 Filaments per Yarn3-200 5-100 5-70 Denier per Yarn 0.6-1200 3-300 4-175 During the spinning process, after the individual polypropylene filaments have been brought together to provide the yarn, it is conventional practice to apply a spin finish to the yarn. The spin finish typically contains lubricant, antistatic and adhesive components to hold the yarn together and improve its processability, e.g., drawability. One spin finish composition which is known to provide generally good results is Lurol 1187 (Goulston Inc., 700 N. Johnson Street, Monroe, NC 28110) which can be applied to the yarn from a solution prepared with a suitable solvent, e.g., as a 5-35 weight percent solution in isopropyl alcohol.
Following spinning, the multifilament yarn is ordinarily subjected to further mechanical processing, e.g., twisting, air entanglement, etc., in order to further enhance its processability. Thus, e.g., the yarn can be ring twisted at a rate of from about 1 to about 5 turns per inch or air entangled at a level of at least about 50 nodes per meter prior to being formed into a surgical suture.
The polypropylene multifilament yarn of this invention is particularly well suited for the construction --- 2.~
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~....
of braided sutures. Preferred suture constructions are disclosed in U.S. Patent Nos. 5,019,093 and 5,059,213, discussed supra, the contents of which are incorporated by reference herein.
The defining structural characteristics of a braided suture manufactured in accordance with the parameters set out in U.S. Patent No. 5,019,093 and ~ `
incorporating the polypropylene multifilament yarn of this -~
invention are:
(1) overall suture denier;
(2) the pattern of the interlocking yarns ~ `
expressed as the pick count, which is to say, the number of crossovers of individual sheath yarns per linear inch of suture;
(3) the number of sheath yarns comprising the brald;
drawn, or stretched, from six to seven times its original length at elevated temperature resulting in its orientation : and an increase in its tensile strength. The stretched monofilament is then collected on a spool for subsequent processing, specifically, an annealing operation which results in the shrinkage of the suture. The various conditions of the extrusion, stretching and annealing steps are indicated to be important for obtaining the desired I
2~ ~3~
polypropylene monofilament suture, one which is characterized by an ultimate elongation of from 35 to 63 percent.
The polypropylene monofilament suture manufacturing process of U.S. Patent No. 4,911,165 is said to provide a suture exhibiting improved compliance while retaining the excellent properties of prior polypropylene monofilament sutures. An increase in the draw ratio during orientation and the allowed shrinkage during annealing is credited with resulting in a monofilament suture of lower modulus at a given level of tensile strength.
As disclosed in U.S. Patent No. 5,217,485, if in the polypropylene monofilament suture manufacturing process described in U.s. Patent No. 3,630,205 the stretched monofilament is permitted to equilibrate, or "rest", prior to undergoing the annealing operation, the resulting suture will exhibit significantly improved properties such as reduced strain energy, increased knot security and reduced out-of-package set even after relatively lengthy periods of shelf storage. The strain energy of a polypropylene i~
monofilament suture is related to the amount of effort required to straighten the suture upon removal of the suture from its package such that the lower the strain energy, the lesser the effort required to straighten the suture prior to use.
Braided sutures fabricated from polypropylene multifilament yarns are known, e.g., from U.S. Patent Nos.
1 5,019,093 and 5,059,213. As disclosed in U.S. Patent No.
¦ 5,019,093, a braided suture manufactured from a variety of materials, polypropylene among them, is co~structed with a significantly greater number of sheath yarns for a given overall denier, the sheath yarns being fabricated from individual filaments of finer denier than those typical of known types of braided suture. The unique construction of -the braided suture of U.S. Patent No. 5,019,093 results in a perceptible improvement in its flexibllity and hand and ?::
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- 3 - -~
reduced chatter and drag compared with the same characteristics in a braided suture of theretofore known construction. U.S.
Patent No. 5,059,213 descrihes a suture of spiroid braid construction which can also be manufactured from various materials including polypropylene. The suture of U.S. Patent No.
5,059,213, like that of U.S. Patent No. 5,019,093, exhibits greater flexibility, better hand and less chatter and drag than other types of braided suture construction. The improved properties of the sutures of U.S. Patent Nos. 5,019,093 and 5,059,213 have largely resulted from their pattern of construction rather than from the physical properties of the yarns utilized in their manufacture.
In accordance with an embodiment of the present invention there is provided a polypropylene multifilam~nt yarn ~;`
produced by the process which comprises melt spinning an isotactic polypropylene employing an extruder equipped with a spinneret and downstream of the extruder a draw frame possessing three pairs of godets, the extruder being operated in one or more zones thereof at a temperature of from about 230 to about 270C, the pressure of the extruder being from about 1000 to about 2000 psi, the temperature of the spinneret being from about 220 to about 250C, the first pair of godets being operated at a temperature of from about 40 to about 90C and an mpm of from about 100 to about 300, the second pair of godets being operated at a temperature of from about 70 to about 130C and an mpm of from about 300 to about 1000 and the third pair of godets being operated at ambient temperature and an mpm of from about 250 to about 1000, the draw ratio of the yarn being from about 2 to about 4 and the shrinkage of the yarn being from about 5 to about 15 percent.
In accordance with another embodiment of the present invention there is provided a suture constructed with a polypropylene multifilament yarn produced by the process which comprises melt spinning an isotactic polypropylene employing an 2 ~
extruder equipped with a spinneret and downstream of the extruder a draw frame possessing three pairs o~ godets, the extruder being operated in one or more zones thereof at a temperature of from about 230 to about 270C, the pressure of the extruder being from about lO00 to about 2000 psi, the temperature of the spinneret being from about 220 to about 250C, the first pair of godets being operated at a temperature of from about 40 to about 90C
and an mpm of from about lO0 to about 300, the second pair of godets being operated at a temperature of from about 70 to about 130C and an mpm of from about 300 to about 1000 and the third pair of godets being operated at ambient temperature and an mpm of from about 250 mpm to about lO00, the draw ratio of the yarn being from about 2 to about 4 and the shrinkage of the yarn being from about 5 to about 15 percent.
Braided sutures fabricated from the foregoing polypropylene multifilament yarn exhibit significantly greater out-of-package flexibility than monofilament polypropylene sutures of the same size or braided sutures made with polypropylene multifilament yarns produced under melt spinning conditions which depart significantly in one or more respects from those recited. Thus, braided sutures incorporating the yarn of this invention can be more easily manipulated and placed at the desired wound closure site, a particularly welcome advantage where the newer laparoscopic surgical procedures are concerned.
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..
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The multifilament yarn of this invention is .
fabricated from a polypropylene resin (isotactic index of at least about 90), preferably one which is already accepted . ~. :
for use as a suture material, e~g., a polypropylene resin having a melt flow index in g/10 min (ASTM D 1238-89) of from about 2 to about 6, preferably from about 2.1 to about 5.0 and most preferably from about 2.5 to about 4.6.
. Xnown and conventional melt spinning apparatus can be used for the production of the polypropylene multifilament yarn herein. However, the melt spinning conditions are fairly critical and for the equipment configuration described in Table I below, are as follows~
.
21 ~ J.~ ~
' ~
TABLE I
MELT SPINNING APPARATUS AND OPERATING CONDITIONS -Apparatus Component,Range of O~erating ParameterOperatingLCondition Extruder barrel temp, zone 1 C 230-250 Extruder barrel temp, zone 2 C 230-270 Extruder barrel temp, zone 3 C 230-270 Extruder barrel pressure, psi 1000-2000 Extruder barrel melt temp., C 230-275 Pump size, cc per rev. .16-.584 Pump rpm 25-35 for size .16 pump ; -~ -~
6-10 for size .584 pump pump temp., C 220-250 Pump pressure, psi 400-1000 Pump melt temp., C 215-255 Block temp, C 220-250 ~ -Clamp temp., C 220-250 Adapter temp., C 220-250 ~ ~ ;
Candle filter, screen, microns 10-100 No. of spinneret orifices 10-200 Diameter of spinneret orifices, 5-30 .001 in. . .
Spinneret temp., C 220-250 Spinneret pressure, psi 400-1500 Spinneret melt temp., C 215-255 cc/hr output, per spinneret orifice 5-20 First pair of godets, C 40-go First pair of godets, mpm100-300 Second pair of godets, C 70-130 Second pair of godets, mpm300-1000 Draw (stretch) ratio 2-4 Third pair of godets, C ambient -Third pair of godets, mpm250-1000 Shrinkage (relaxation), percent 5-15 ~ 2 ~ ~ ~3 3~
-7- ~
~ ~ ,,,, ,i,.
Properties of the individual polypropylene filaments and the yarns incorporating the filaments are ;~
advantaqeouslY as set forth in Table II below~
: ' ' , ' `
TABLE II ~ , PROPERTIESQ F INDIVIDUAL FILAMENTS AND YARNS
More Broad Preferred Preferred ` ;~
Ranqe Range Ranqe Denier per Filament 0.2-6 0.6-3 0.8-2.5 Filaments per Yarn3-200 5-100 5-70 Denier per Yarn 0.6-1200 3-300 4-175 During the spinning process, after the individual polypropylene filaments have been brought together to provide the yarn, it is conventional practice to apply a spin finish to the yarn. The spin finish typically contains lubricant, antistatic and adhesive components to hold the yarn together and improve its processability, e.g., drawability. One spin finish composition which is known to provide generally good results is Lurol 1187 (Goulston Inc., 700 N. Johnson Street, Monroe, NC 28110) which can be applied to the yarn from a solution prepared with a suitable solvent, e.g., as a 5-35 weight percent solution in isopropyl alcohol.
Following spinning, the multifilament yarn is ordinarily subjected to further mechanical processing, e.g., twisting, air entanglement, etc., in order to further enhance its processability. Thus, e.g., the yarn can be ring twisted at a rate of from about 1 to about 5 turns per inch or air entangled at a level of at least about 50 nodes per meter prior to being formed into a surgical suture.
The polypropylene multifilament yarn of this invention is particularly well suited for the construction --- 2.~
-8~
~....
of braided sutures. Preferred suture constructions are disclosed in U.S. Patent Nos. 5,019,093 and 5,059,213, discussed supra, the contents of which are incorporated by reference herein.
The defining structural characteristics of a braided suture manufactured in accordance with the parameters set out in U.S. Patent No. 5,019,093 and ~ `
incorporating the polypropylene multifilament yarn of this -~
invention are:
(1) overall suture denier;
(2) the pattern of the interlocking yarns ~ `
expressed as the pick count, which is to say, the number of crossovers of individual sheath yarns per linear inch of suture;
(3) the number of sheath yarns comprising the brald;
(4) the denier of the individual filaments comprising each sheath yarn; and, (5) the denier of the core, where present.
The term "braid" or "braided" as applied to the suture of U.S. Patent No. 5,019,093 refers to an arrangement of discrete units, or bundles, denominated "sheath yarns", made up of individual filaments with individual sheath yarns interlocking or interlacing each other in a regular criss-cross pattern.
The term "pick count" refers to the number of crossovers of sheath yarns per linear inch of suture and, together with the overall denier of the suture, the denier of the individual filaments constituting a sheath yarn and the number of sheath yarns employed, defines the principal construction characteristics of the braided suture.
The braided suture can optionally possess a core component around which the braid is constructed.
(1) Overall Denier of the Suture -9- ~ ~
The overall denier of the braided suture can vary from about 15 to about 3000. Within this range, the ranges of overall denier for particular sutures are: from about 15 to about 20 denier; from above about 20 to about 40 denier; ~ ;
from above about 40 to about 70 denier; from above about 70 to about 180 denier; from above about 180 to about 300 denier; from above about 300 to about 450 denier; from above about 450 to about 800 denier; from above about 800 to about 1200 denier; from above about 1200 to about 1600 denier; -~
a~d, from above about 1600 to about 2500 denier.
(2) Pattern of the Interlocking Sheath Yarns (Pick Count) For a suture of any range of overall denier, pick count can vary from about 50 to about 100 crossovers/inch with about 55-80 crossovers/inch being preferred. For sutures constructed within any range of overall denier, as larger numbers of sheath yarns are employed, the pick-count for acceptable sutures will also increase within the above ranges.
For a suture of a particular range of denier and number of sheath yarns, pick count is advantageously established to achieve a balance in the properties deslred.
In general, with increasing pick count, surface roughness of the suture tends to increase and with decreasing pick count, the ability of the external braided sheath to contain the core (if present) tends to decrease even reaching the point where the braid may become so loose as to result in the core protruding therethrough, the occurrence of which is often referred to as "core popping".
For sutures of any specific denier range and number of sheath yarns, it is preferable to have as low a pick count as possible in order to achieve optimum surface smoothness, consistent, of course, with the need to provide a compact braid which prevents core popping (where a core is present).
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(3) The Number of Sheath Yarns The number of sheath yarns bears some relation to overall suture denier, the number generally increasing with ;~
the weight of the suture. Thus, across the range of suture weight (denier) indicated above, the braided suture can be constructed with from about 4 up to as many as about 36 individual sheath yarns constructed from individual filaments having the deniers discussed below.
Table III below sets forth broad and preferred ranges for the numbers of sheath yarns which are suitable ;; ;-~
for the construction of braided sutures of various ranges of overall denier. The pick counts of the sutures vary from about 50 to about 100 and deniers of individual filaments ~ -vary from about 0.2 to about 6.0 for the broad range of number of sheath yarns and the pick counts vary from about 55 to about 80 and the deniers of individual filaments vary from about 0.6 to about 3.0, and advantageously from about 0.8 to about 2.5, for the preferred range of number of sheath yarns.
: .
TABLE III
SHEATH YARNS RELATED TO SUTURE DENIER
Number of -Number of Sh~ath Sheath Yarns Yarns Overall Suture Suture Size (Broad (Preferred Denier Range) Range) from about 15 to 7/0, 8/0 3-12 3-8 about 40 greater than about 6/0 4-16 6-12 40 to about 70 greater than about 5/0 4-16 6-12 70 to about 180 greater than about 4/0 8-20 10-14 180 to about 300 ~;~
greater than about 3/0 12-20 12-18 ~:.
-~
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300 to about 450 greater than about 2/0 16-32 20-30 450 to about 800 greater than about 0 20-40 24-36 800 to about 1200 greater than about 1,2 20-40 24-36 1200 to about 2500 While the sheath yarns need not be twisted, it is generally preferred that they be provided with a twist so as to minimize snagging during braid construction.
(4) Individual Filament Denier The individual filaments comprising each sheath yarn can vary in weight from about 0.2 to about 6.0 denier, preferably from about 0.6 to about 3.0 denier and more preferably from about 0.8 to about 2.5 denier. The number of such filaments present in a particular sheath yarn will depend on the overall denier of the suture as well as the number of sheath yarns utilized in the construction of the suture. Table IV sets forth some typical numbers of filaments per sheath yarn for both the broad and preferred ranges of filament weight:
TABLE IV
NUMBER OF FILAMENTS PER SHEATH YARN
":
approximate approximate minimum maximum fiber denier 23 90 0.2 9 36 0.5 o.g - 3 10 1.8 l 3 6.0 ., (5) Core . . ~ .
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For all but the lowest range of overall denier, the braided suture can be constructed around a filamentous ~
core which can itself be braided or provided in some other ~ ~`
configuration such as a twist, ply, cable, etc. The filament(s) comprising the core need not be as fine as those comprising the sheath yarns. The core is preferably a cabled core as disclosed in commonly assigned copending PCT/US 91/09137, the contents of which are incorporated by reference herein.
The cabled core of PCT/US 91/09137 is manufactured in a separate operation and is assembled from a plurality of individual yarns, e.g., from about 2 to about 200, and preferably from about 3 to about 80 yarns. Each yarn to be incorporated into the core is given a twist in one direction, the "front" direction, the twisted yarns then being combined into a core which is then twisted in the opposite direction, the "back" direction, to provide the cabled core unit around which the remainder of the suture is constructed. This arrangement has the desirable effect of preventing or minimizing the possibility of core popping. ~-Depending upon the material used in the construction of the core, it may be desirable to heat set and/or stretch the core in a known manner prior to final assembly of a braided suture incorporating the cabled core.
The denier of the individual yarns comprising the core is not particularly critical and can range in most cases from about 10 to about 100 and preferably from about 15 to about 70. The degree of twist which is applied to the individual yarns can vary widely with from about 200 to about 1500 turns per meter, and preferably, from about 240 to about 1200 turns per meter, generally providing good results.
The overall denier of the cabled core is, of course, determined by the number and individual deniers of the core yarns from which the core is constructed. For many suture constructions, core denier can range from about 20 to ~., .' .: .
2 ~
about 80 and preferably from about 25 to about 50 in the smallest size suture and from about 800 to about 2400 and preferably from about 1000 to about 2200 in the largest size suture. In order to increase the total core denier, it is contemplated that for larger suture cores it may be desirable to ply two or more yarns together, preferably before front twisting of the yarns.
The degree of reverse-direction, or "back" twist, should be determined for a particular suture construction so as to provide a balanced structure. Yarn-to-yarn twist levels can he compared through the "coefficient of twist function" alpha which is related to the helical angle. The coefficient of twist function can be calculated from the relationship alpha = K AO.lllD
in which alpha is the coefficient of twist, K is the twist level in turns per meter and D is the denier of the resulting twisted product, e.g., twisted yarn or core. In other words, the coefficient of twist, alpha, is given by the product of yarn twist, K, and the square root of yarn count, i.e. mass per unit length or linear density. This coefficient of twist is also directly proportional to the helical or twist angle in yarns having the same solid density (or melt density), so alpha determined for one material can be applied to materials of the same density.
Therefore, yarns having different deniers and the same coefficient of twist are geometrically similar, with the coefficient of twist thus being independent of the yarn denier.
The coefficient of twist in the cabled core construction is preferably at least about 24, more preferably at least about 28 and most preferably at least about 32. -To apply equal deformation to yarns of different denier, the coefficient of twist of the yarns should be the same. Yarns with higher deformation will have a higher coefficient of twist. For many braided suture constructions, the twist level in turns per meter of the -cabled core component can range from about 200 to about 1500 turns per meter and preferably from about 240 to about 1200 turns per meter.
More speclfically, the cabled core is constructed from a plurality oE individual yarns possessing a first twist of from about 100 to about 1500 turns per meter, the twisted yarns being assembled into a core possessiny a second, opposite twist of from about 100 to about 1200 turns per meter. Preferably, the individual yarns possess a first twist of from about 200 to about 1200 turns per meter with the second opposite twist of the core being about 200 to about 1100 turns per meter.
In practice, once the desired overall core denier and denier of the yarns used to make the core are known, the coefficient of twist can be calculated for the overall core and individual yarns in order to approximate a balanced core structure. The above equation is first used to determine the degree of back twist, K, required to obtain a core of the desired overall core denier having a desired coefficient of twist, alpha, greater than 24. Using the same value for the coefficient of twist, the equation is then solved using the denier of the individual yarns to determine the approximate degree of front twist which must be applied to the individual yarns in order to obtain a balanced structure. - -If multiple plied yarns are to be back-twisted to ~-form the cabled core, the plied yarns are front twisted -using the equation to determine the degree of twist required to obtain a balanced structure. After the cabled core is constructed, a simple loop test can be performed to determine whether a balanced structure has been achieved. In one suitable test, a one meter length of core is sampled and the ends of the core sample are brought together with the -- ~ 2~
remainder of the core allowed to hang and form a loop. If the loop remains substantially open, i.e., without twisting or with a twist less than 360, the core structure is considered balanced. Howeve~r, if the loop twists more than 360(2 turns) in either direction, the structure is unbalanced and should be modified accordingly. It should be noted that if a cabled core has too much twist in one direction, then the loop will take a twist in the opposite direction. Thus, if the loop twists in a back direction (z), the amount of twist applied to the core or yarn in that back direction (z) should be increased, or the degree of twist in the opposite front direction(s) should be decreased. As will be appreciated, minor variations may be required in order to obtain the desired balanced core structure.
For the preferred suture constructions of U.S.
Patent No. 5,019,093, suture sizes 7/0 and smaller can be made without a core component while a core can be optionally included in sutures of size 6/0. Cores for suture sizes 4/0, 5/0 and 6/0 can be constructed by twisting individual yarns in the front direction and then reverse-twisting individual yarns together. For sutures of size 3/0 and larger, it is preferred to obtain the desired overall core ~ ;~
denier by plying multiple yarns together, then front ;~
twisting and then back twisting the multiple plied yarns together to form the cabled core. In describing the cabled ; `~
core, it is useful to identify the number of filaments in the structure in terms of the number of filaments in each yarn times the number of yarns plied together times the number of plied yarns which are back twisted together to form the cabled core.
Table V below provides some typical core deniers for polypropylene braided sutures of various deniers manufactured in accordance with U.S. Patent No. 5,019,093.
-16~
,- ~-~ ~ .
TABLE V
CORE DENIER RELATED TO SUTURE DENIER
::
Denler of Denier of :.Cabled Core Cabled Core . -~
Overall Suture Suture (Broad (Preferred :-~
Denier Size Range) Range) ~rom about 15 to 7/0, 8/0 none none about 40 greater than about 6/0 none none :.
40 to about 70 greater than about 5/0 20-70 35-55 70 to about 180 greater than about 4/0 30-100 50-80 180 to about 300 greater than about 3/0 70-220 120-170 ~ :
300 to about 450 greater than about 2/0 160-480 260-390 450 to about 800 . ~
greater than about 0 250-800 400-610 800 to about 1200 .~ ~
greater than about 1,2 450-2000 720-1600 ;~
1200 to about 2500 `~;
. ,, For a braided suture of given overall denier, the ranges of pick count, number of sheath yarns and denier of individual filaments comprising a sheath yarn and cabled core are related to each other as set forth in Table VI :: .~ ~-below~
'., ' ~':
: ..
:
~,.~9,.. .. .. ... .. ... . .. . .. . ~. i ... .
TABLE VI
STRUCTURAL PROPERTIES OF BRAIDED SUTURES OF VARIOUS SIZES
Deni.er of Overall Number of Individual Denier of Suture Pick Count Sheath Filaments Cabled Denier Yarns Core greater from about from about from about from about than about 50 to 4 to about 0.2 to 20 to 120 to about 100 16 about 3.0 about 70 about 180 greater from about from about from about from about than about 50 to 8 to about 0.2 to 30 to 180 to about 100 20 about 3.0 about 100 about 300 greater from about from about from about from about than about 50 to 12 to 0.2 to 70 to ~`
300 to about 100 about 20 about 6.0 about 220 ; ~ .
about 450 ;~
greater from about from about from about from about -- :
than about 50 to 16 to 0.2 to 150 to ; : `.
450 to about 100 about 20 about 6.0 about 500 :~ `:
about 800 :~
greater from about from about from about from about . :~
than about 50 to 20 to 0.2 to ~ 250 to `~
800 to about 100 about 40 about 6.0 about 800 about 1200 . -.
greater from about from about from about from about than about 50 to 20 to 0.2 to 400 to 1200 to about 100 about 40 about 6.0 about 1400 about 1600 `~
greater from about from about from about from about :
than about 50 to 20 to 0.2 to 600 to ~:
1600 to about 100 about 40 about 6.0 about 2000 about 2500 Table VII, below, sets forth the preferred ranges of pick count, number of sheath yarns, denier of individual filaments in a sheath yarn and cabled core:
' :`::
., 3 ~
2 1 ~
TABLE VII
STRUCTURAL PROPERTIES OF PREFERRED
BRAIDED SUTURES OF VARIOUS SIZES
Denier of Denier of Overall Number of Individual Cabled Suture Pick Count Sheath Filaments Core Denier Yarns (Optional) greater from about from about from about from about than about 55 to 6 to about 0.8 to 35 to 120 to about 80 12 about 2.5 about 55 about 180 greater from about from about from about from about ;:-than about 55 to 10 to 0.8 to 50 to 180 to about 80 about 14 about 2.5 about 80 about 300 greater from about from about from about from about than about 55 to 12 to 0.8 to 120 to 300 to about 80 about 18 about 2.5 about 170 .
about 450 greater from about from about from about from about than about 55 to 10 to 0.8 to 260 to 450 to about 80 about 30 about 2.5 about 390 about 800 greater from about from about from about from about than about 55 to 24 to 0.8 to 400 to - -800 to about 80 about 36 about 2.5 about 610 about 1200 , i greater from about from about from about from about than about 55 to 24 to 0.8 to 720 to -1200 to about 80 about 36 about 2.5 about 1000 about 1600 greater from about from about from about from about than about 55 to 24 to 0.8 to ~ 1000 to -~-~
1600 to about 80 about 36 about 2.5 about 1600 about 2500 U.S. Patent No. 5,059,213 describes another type of suture, namely, a spiroid braided suture, which can be ~
constructed from the polypropylene multifilament yarn of -this invention. The defining structural characteristics of -~
such a suture are: - i;
(1) suture size (i.e., suture diameter);
¦ (2) overall suture denier;
, ~ ^ 2~ ~ :3~ ~
-19- ~"
(3) the pattern of the interlocking yarns;
(4) pick count;
(5) the number of yarns comprising the braid;
The term "braid" or "braided" as applied to the suture of U.S. Patent No. 5,019,093 refers to an arrangement of discrete units, or bundles, denominated "sheath yarns", made up of individual filaments with individual sheath yarns interlocking or interlacing each other in a regular criss-cross pattern.
The term "pick count" refers to the number of crossovers of sheath yarns per linear inch of suture and, together with the overall denier of the suture, the denier of the individual filaments constituting a sheath yarn and the number of sheath yarns employed, defines the principal construction characteristics of the braided suture.
The braided suture can optionally possess a core component around which the braid is constructed.
(1) Overall Denier of the Suture -9- ~ ~
The overall denier of the braided suture can vary from about 15 to about 3000. Within this range, the ranges of overall denier for particular sutures are: from about 15 to about 20 denier; from above about 20 to about 40 denier; ~ ;
from above about 40 to about 70 denier; from above about 70 to about 180 denier; from above about 180 to about 300 denier; from above about 300 to about 450 denier; from above about 450 to about 800 denier; from above about 800 to about 1200 denier; from above about 1200 to about 1600 denier; -~
a~d, from above about 1600 to about 2500 denier.
(2) Pattern of the Interlocking Sheath Yarns (Pick Count) For a suture of any range of overall denier, pick count can vary from about 50 to about 100 crossovers/inch with about 55-80 crossovers/inch being preferred. For sutures constructed within any range of overall denier, as larger numbers of sheath yarns are employed, the pick-count for acceptable sutures will also increase within the above ranges.
For a suture of a particular range of denier and number of sheath yarns, pick count is advantageously established to achieve a balance in the properties deslred.
In general, with increasing pick count, surface roughness of the suture tends to increase and with decreasing pick count, the ability of the external braided sheath to contain the core (if present) tends to decrease even reaching the point where the braid may become so loose as to result in the core protruding therethrough, the occurrence of which is often referred to as "core popping".
For sutures of any specific denier range and number of sheath yarns, it is preferable to have as low a pick count as possible in order to achieve optimum surface smoothness, consistent, of course, with the need to provide a compact braid which prevents core popping (where a core is present).
. , 2 ~
- 1 0 ~
.: :"~
(3) The Number of Sheath Yarns The number of sheath yarns bears some relation to overall suture denier, the number generally increasing with ;~
the weight of the suture. Thus, across the range of suture weight (denier) indicated above, the braided suture can be constructed with from about 4 up to as many as about 36 individual sheath yarns constructed from individual filaments having the deniers discussed below.
Table III below sets forth broad and preferred ranges for the numbers of sheath yarns which are suitable ;; ;-~
for the construction of braided sutures of various ranges of overall denier. The pick counts of the sutures vary from about 50 to about 100 and deniers of individual filaments ~ -vary from about 0.2 to about 6.0 for the broad range of number of sheath yarns and the pick counts vary from about 55 to about 80 and the deniers of individual filaments vary from about 0.6 to about 3.0, and advantageously from about 0.8 to about 2.5, for the preferred range of number of sheath yarns.
: .
TABLE III
SHEATH YARNS RELATED TO SUTURE DENIER
Number of -Number of Sh~ath Sheath Yarns Yarns Overall Suture Suture Size (Broad (Preferred Denier Range) Range) from about 15 to 7/0, 8/0 3-12 3-8 about 40 greater than about 6/0 4-16 6-12 40 to about 70 greater than about 5/0 4-16 6-12 70 to about 180 greater than about 4/0 8-20 10-14 180 to about 300 ~;~
greater than about 3/0 12-20 12-18 ~:.
-~
~ ::
300 to about 450 greater than about 2/0 16-32 20-30 450 to about 800 greater than about 0 20-40 24-36 800 to about 1200 greater than about 1,2 20-40 24-36 1200 to about 2500 While the sheath yarns need not be twisted, it is generally preferred that they be provided with a twist so as to minimize snagging during braid construction.
(4) Individual Filament Denier The individual filaments comprising each sheath yarn can vary in weight from about 0.2 to about 6.0 denier, preferably from about 0.6 to about 3.0 denier and more preferably from about 0.8 to about 2.5 denier. The number of such filaments present in a particular sheath yarn will depend on the overall denier of the suture as well as the number of sheath yarns utilized in the construction of the suture. Table IV sets forth some typical numbers of filaments per sheath yarn for both the broad and preferred ranges of filament weight:
TABLE IV
NUMBER OF FILAMENTS PER SHEATH YARN
":
approximate approximate minimum maximum fiber denier 23 90 0.2 9 36 0.5 o.g - 3 10 1.8 l 3 6.0 ., (5) Core . . ~ .
~ ~ ~ 3 ~l ~ 8 ~
'~
For all but the lowest range of overall denier, the braided suture can be constructed around a filamentous ~
core which can itself be braided or provided in some other ~ ~`
configuration such as a twist, ply, cable, etc. The filament(s) comprising the core need not be as fine as those comprising the sheath yarns. The core is preferably a cabled core as disclosed in commonly assigned copending PCT/US 91/09137, the contents of which are incorporated by reference herein.
The cabled core of PCT/US 91/09137 is manufactured in a separate operation and is assembled from a plurality of individual yarns, e.g., from about 2 to about 200, and preferably from about 3 to about 80 yarns. Each yarn to be incorporated into the core is given a twist in one direction, the "front" direction, the twisted yarns then being combined into a core which is then twisted in the opposite direction, the "back" direction, to provide the cabled core unit around which the remainder of the suture is constructed. This arrangement has the desirable effect of preventing or minimizing the possibility of core popping. ~-Depending upon the material used in the construction of the core, it may be desirable to heat set and/or stretch the core in a known manner prior to final assembly of a braided suture incorporating the cabled core.
The denier of the individual yarns comprising the core is not particularly critical and can range in most cases from about 10 to about 100 and preferably from about 15 to about 70. The degree of twist which is applied to the individual yarns can vary widely with from about 200 to about 1500 turns per meter, and preferably, from about 240 to about 1200 turns per meter, generally providing good results.
The overall denier of the cabled core is, of course, determined by the number and individual deniers of the core yarns from which the core is constructed. For many suture constructions, core denier can range from about 20 to ~., .' .: .
2 ~
about 80 and preferably from about 25 to about 50 in the smallest size suture and from about 800 to about 2400 and preferably from about 1000 to about 2200 in the largest size suture. In order to increase the total core denier, it is contemplated that for larger suture cores it may be desirable to ply two or more yarns together, preferably before front twisting of the yarns.
The degree of reverse-direction, or "back" twist, should be determined for a particular suture construction so as to provide a balanced structure. Yarn-to-yarn twist levels can he compared through the "coefficient of twist function" alpha which is related to the helical angle. The coefficient of twist function can be calculated from the relationship alpha = K AO.lllD
in which alpha is the coefficient of twist, K is the twist level in turns per meter and D is the denier of the resulting twisted product, e.g., twisted yarn or core. In other words, the coefficient of twist, alpha, is given by the product of yarn twist, K, and the square root of yarn count, i.e. mass per unit length or linear density. This coefficient of twist is also directly proportional to the helical or twist angle in yarns having the same solid density (or melt density), so alpha determined for one material can be applied to materials of the same density.
Therefore, yarns having different deniers and the same coefficient of twist are geometrically similar, with the coefficient of twist thus being independent of the yarn denier.
The coefficient of twist in the cabled core construction is preferably at least about 24, more preferably at least about 28 and most preferably at least about 32. -To apply equal deformation to yarns of different denier, the coefficient of twist of the yarns should be the same. Yarns with higher deformation will have a higher coefficient of twist. For many braided suture constructions, the twist level in turns per meter of the -cabled core component can range from about 200 to about 1500 turns per meter and preferably from about 240 to about 1200 turns per meter.
More speclfically, the cabled core is constructed from a plurality oE individual yarns possessing a first twist of from about 100 to about 1500 turns per meter, the twisted yarns being assembled into a core possessiny a second, opposite twist of from about 100 to about 1200 turns per meter. Preferably, the individual yarns possess a first twist of from about 200 to about 1200 turns per meter with the second opposite twist of the core being about 200 to about 1100 turns per meter.
In practice, once the desired overall core denier and denier of the yarns used to make the core are known, the coefficient of twist can be calculated for the overall core and individual yarns in order to approximate a balanced core structure. The above equation is first used to determine the degree of back twist, K, required to obtain a core of the desired overall core denier having a desired coefficient of twist, alpha, greater than 24. Using the same value for the coefficient of twist, the equation is then solved using the denier of the individual yarns to determine the approximate degree of front twist which must be applied to the individual yarns in order to obtain a balanced structure. - -If multiple plied yarns are to be back-twisted to ~-form the cabled core, the plied yarns are front twisted -using the equation to determine the degree of twist required to obtain a balanced structure. After the cabled core is constructed, a simple loop test can be performed to determine whether a balanced structure has been achieved. In one suitable test, a one meter length of core is sampled and the ends of the core sample are brought together with the -- ~ 2~
remainder of the core allowed to hang and form a loop. If the loop remains substantially open, i.e., without twisting or with a twist less than 360, the core structure is considered balanced. Howeve~r, if the loop twists more than 360(2 turns) in either direction, the structure is unbalanced and should be modified accordingly. It should be noted that if a cabled core has too much twist in one direction, then the loop will take a twist in the opposite direction. Thus, if the loop twists in a back direction (z), the amount of twist applied to the core or yarn in that back direction (z) should be increased, or the degree of twist in the opposite front direction(s) should be decreased. As will be appreciated, minor variations may be required in order to obtain the desired balanced core structure.
For the preferred suture constructions of U.S.
Patent No. 5,019,093, suture sizes 7/0 and smaller can be made without a core component while a core can be optionally included in sutures of size 6/0. Cores for suture sizes 4/0, 5/0 and 6/0 can be constructed by twisting individual yarns in the front direction and then reverse-twisting individual yarns together. For sutures of size 3/0 and larger, it is preferred to obtain the desired overall core ~ ;~
denier by plying multiple yarns together, then front ;~
twisting and then back twisting the multiple plied yarns together to form the cabled core. In describing the cabled ; `~
core, it is useful to identify the number of filaments in the structure in terms of the number of filaments in each yarn times the number of yarns plied together times the number of plied yarns which are back twisted together to form the cabled core.
Table V below provides some typical core deniers for polypropylene braided sutures of various deniers manufactured in accordance with U.S. Patent No. 5,019,093.
-16~
,- ~-~ ~ .
TABLE V
CORE DENIER RELATED TO SUTURE DENIER
::
Denler of Denier of :.Cabled Core Cabled Core . -~
Overall Suture Suture (Broad (Preferred :-~
Denier Size Range) Range) ~rom about 15 to 7/0, 8/0 none none about 40 greater than about 6/0 none none :.
40 to about 70 greater than about 5/0 20-70 35-55 70 to about 180 greater than about 4/0 30-100 50-80 180 to about 300 greater than about 3/0 70-220 120-170 ~ :
300 to about 450 greater than about 2/0 160-480 260-390 450 to about 800 . ~
greater than about 0 250-800 400-610 800 to about 1200 .~ ~
greater than about 1,2 450-2000 720-1600 ;~
1200 to about 2500 `~;
. ,, For a braided suture of given overall denier, the ranges of pick count, number of sheath yarns and denier of individual filaments comprising a sheath yarn and cabled core are related to each other as set forth in Table VI :: .~ ~-below~
'., ' ~':
: ..
:
~,.~9,.. .. .. ... .. ... . .. . .. . ~. i ... .
TABLE VI
STRUCTURAL PROPERTIES OF BRAIDED SUTURES OF VARIOUS SIZES
Deni.er of Overall Number of Individual Denier of Suture Pick Count Sheath Filaments Cabled Denier Yarns Core greater from about from about from about from about than about 50 to 4 to about 0.2 to 20 to 120 to about 100 16 about 3.0 about 70 about 180 greater from about from about from about from about than about 50 to 8 to about 0.2 to 30 to 180 to about 100 20 about 3.0 about 100 about 300 greater from about from about from about from about than about 50 to 12 to 0.2 to 70 to ~`
300 to about 100 about 20 about 6.0 about 220 ; ~ .
about 450 ;~
greater from about from about from about from about -- :
than about 50 to 16 to 0.2 to 150 to ; : `.
450 to about 100 about 20 about 6.0 about 500 :~ `:
about 800 :~
greater from about from about from about from about . :~
than about 50 to 20 to 0.2 to ~ 250 to `~
800 to about 100 about 40 about 6.0 about 800 about 1200 . -.
greater from about from about from about from about than about 50 to 20 to 0.2 to 400 to 1200 to about 100 about 40 about 6.0 about 1400 about 1600 `~
greater from about from about from about from about :
than about 50 to 20 to 0.2 to 600 to ~:
1600 to about 100 about 40 about 6.0 about 2000 about 2500 Table VII, below, sets forth the preferred ranges of pick count, number of sheath yarns, denier of individual filaments in a sheath yarn and cabled core:
' :`::
., 3 ~
2 1 ~
TABLE VII
STRUCTURAL PROPERTIES OF PREFERRED
BRAIDED SUTURES OF VARIOUS SIZES
Denier of Denier of Overall Number of Individual Cabled Suture Pick Count Sheath Filaments Core Denier Yarns (Optional) greater from about from about from about from about than about 55 to 6 to about 0.8 to 35 to 120 to about 80 12 about 2.5 about 55 about 180 greater from about from about from about from about ;:-than about 55 to 10 to 0.8 to 50 to 180 to about 80 about 14 about 2.5 about 80 about 300 greater from about from about from about from about than about 55 to 12 to 0.8 to 120 to 300 to about 80 about 18 about 2.5 about 170 .
about 450 greater from about from about from about from about than about 55 to 10 to 0.8 to 260 to 450 to about 80 about 30 about 2.5 about 390 about 800 greater from about from about from about from about than about 55 to 24 to 0.8 to 400 to - -800 to about 80 about 36 about 2.5 about 610 about 1200 , i greater from about from about from about from about than about 55 to 24 to 0.8 to 720 to -1200 to about 80 about 36 about 2.5 about 1000 about 1600 greater from about from about from about from about than about 55 to 24 to 0.8 to ~ 1000 to -~-~
1600 to about 80 about 36 about 2.5 about 1600 about 2500 U.S. Patent No. 5,059,213 describes another type of suture, namely, a spiroid braided suture, which can be ~
constructed from the polypropylene multifilament yarn of -this invention. The defining structural characteristics of -~
such a suture are: - i;
(1) suture size (i.e., suture diameter);
¦ (2) overall suture denier;
, ~ ^ 2~ ~ :3~ ~
-19- ~"
(3) the pattern of the interlocking yarns;
(4) pick count;
(5) the number of yarns comprising the braid;
(6) the denier of the filaments comprising each yarn; and, (7) the denier of the core, where present.
The spiroid braided suture can be of "solid"
construction, i.e., a structure in which the filamentous material of its construction occupies substantially the entire cross-sectional area of the suture with a relatively -minor percentage of such area constituting void spaces or `
interstices between adjacent yarns and fibers, or it can possess a lumen, optionally occupied by a core component as in the braided cored suture of U.S. Patent No. 5,019,093, ~ `~
supra.
'..'`~" ~'"
(1) Suture Size (i.e., Suture Diameter) The suture size can be expressed in terms of ;-standard sizes, corresponding to certain ranges of diameter (in millimeters), as set forth in the United States Pharmaco~oeia (USP). Standard sizes of spiroid braided suture are set forth in Table VIII as follows~
TABLE VIII
SUTURE SIZE
USP Suture Size Diamater (mm) 2 0.50-0.599 1 0.40-0.499 0 (1/0) 0-35-0-399 2/0 0.30_0.399 3/o 0.20-0.249 4/o 0.15-0.199 5/0 0.10-0.149 6/0 0.070-o.ogg 7/0 0.050-0.069 8/0 0.~40-0.049 ; ~ 2 ~ ~ :J ~ ~ g (2) Overall Denler of the Suture The overall denier of the braided suture can vary from about 15 to about 4000. Within this range, the ranges of overall denier for particular sutures are: from about 15 to about 20 denier; from above about 20 to about 40 denier;
from above about 40 to about 70 denier; from above about 70 to about 180 denier; from above about 180 to about 300 denier; from above about 300 to about 450 denier; from above -about 450 to about 800 denier; from above about 800 to about ;~
1200 denier; from above about 1200 to about 1600 denier;
and, from above 1600 to 2500 denier.
(3) Pattern of the Interlocking Yarns Unlike the braided structure of U.S. Patent No.
5,019,093 where the yarns form a criss-cross pattern which may be thought of as confined to the surface of a hollow cylinder, a spiroid braided suture consists of a pattern of interlocking yarns which may be considered as extending from the surface of a cylinder to its center thus providing a solid structure as defined above. The characteristic -pattern of a spiroid braided suture is clearly different from that of the braided suture of U.S. Patent No.
5,019,093. In the former, the yarns are essentially parallel to the longitudinal axis of the suture whereas in the latter, the yarns cross over each other at some angle to the longitudinal axis of the suture.
(4) Pick Count Pick count is the number of stitches per inch lying in a single line parallel to the longitudinal axis of the suture as viewed from the surface of the suture.
Suitable pick counts can vary from 40-80 stitches/inch and preferably from 50-70 stitches/inch.
(5) The Number of Yarns ' ~, ' , . ' ' :' ., ' ' l 3 ~
The number of yarns employed in the construction of the spiroid braided suture bears some relation to overall suture denier, the number of yarns generally increasing with ~ .
the weight of the suture. Thus, across the range of suture weight (denier) indicated above, a spiroid braided suture can be fabricated with from about 6 up to as many as about 30 individùal yarns constructed from individual filaments having the deniers discussed belo~
Table IX below sets forth broad and preferred ranges for the numbers of yarns which are suitable for the construction of spiroid braided sutures of various ranges of :~
overall denier. The deniers of individual filaments in a yarn can vary from about 0.2 to about 6.0 for the broad range of number of yarns and the deniers of individual :.
filaments can vary from about 0.6 to about 3.0, and advantageously from about 0.8 to about 2.5, for the preferred range of number of yarns.
TABLE IX :
NUMBER OF YARNS RELATED TO SUTURE DENIER
Number of Number of Yarns Yarns :~
Overall SutureSuture(Broad (Preferred Denier Size Range) Range) .
from about 15 to7/0, 8/03-12 3-6 about 40 greater than about 6/0 6-15 6-12 ~.
40 to about 70 greater than about 5/0 6-15 6-12 70 to about 180 greater than about 4/0 6-26 9-22 180 to about 300 greater than about 3/0 20-36 24-32 300 to about 450 greater than about 2/0 40-58 46-54 450 to about 800 2 ~ .L ~ 8 greater than about 0 60-80 66-74 800 to about 1200 greater than about 1,2 84-170 88-164 1200 to about 2500 While the yarns need not be twisted, it is generally preferred that they be provided with a slight twist so as to minimize snagging during construction.
(6) Individual Filament Denier The individual filaments comprising each yarn can vary in weight from about 0.2 to about 6.0 denier, preferably from about 0.6 to about 3.0 denier and more preferably from about 0.8 to about 2.5 denier. The number of such filaments present in a particular yarn will depend `
on the overall denier of the suture as well as the number of yarns utilized in the construction of the suture. Table X
sets forth some typical numbers of filaments per yarn for both the broad and pre~erred ranges of filament weight~
TABLE X
NUMBER OF FILAMENTS PER YARN
Approximate ApproximateFilamer.t Miniumum Maximum Denier 23 135 0.2 9 54 0.5 o.g 3 15 1.8 -~
l 5 6.0 ~'~
(7) Core (Optional) For all but the smallest sizes of spiroid braided suture, the suture, although substantially solid in the sense defined above, can optionally contain some small amount of void space, generally not exceeding 25% or so in the larger sutures sizes, which, if desired, can be 2~ 3.
." ~, " ,.
partially or substantially completely filled with a core component. A core may be advantageous where it is desired to increase the density of the suture and/or preserve its roundness. The core, where present, can be monofilamentous or multifilamentous. In the case of the latter, the core itself can be braided or can be provided with some other configuration such as a twist, ply, cable, etc. Preferably, the core is a cabled core of the type disclosed in PCT/US
91/09137, discussed supra.
Table XI below provides some typical core deniers for spiroid braided sutures of various deniers:
TABLE XI
CORE DENIER RELATED TO SUTURE DENIER
- Maximum Denier ofMaximum Denier Overall Suture Suture Optional of Optional Core Denier Size Core (Broad(Preferred Range) Range) :.
from about 15 to 8/0, 7/0 none none about 40 greater than about 6/0 none none 40 to about 70 greater than about 5/0 25-65 35-55 70 to about 180 greater than about 4/0 40-80 50-70 180 to about 300 greater than about 3/0 120-170 130-160 300 to about 450 greater than about 2/0 290-340 310-330 450 to about 800 greater than about 0 450-550 470-530 800 to about 1200 greater than about 1,2 800-1600 850-1500 1200 to about 2500 -21~ 31 ~
' :
It can be advantageous to apply one or more coating compositions to a braided suture manufactured with the polypropylene multifilament yarn of this invention in order to improve one or more of its properties such as surface lubricity and knot tiedown behavior. A variety of suture coating compositions proposed for either or both purposes is known in the art, e.g., those disclosed in U.S.
Patent No. 4,047,533, the contents of which are incorporated i by reference herein. -~
It is also within the scope of this invention to impregnate the suture with, or otherwise apply thereto, one or more medico-surgically useful substances, e.g.; those which accelerate or beneficially modify the healing process when the suture is applied to a wound or surgical site. So, for example, the braided suture can be provided with a therapeutic agent which will be deposited at the sutured site. The therapeutic agent can be chosen for its i antimicrobial properties, capability for promoting wound repair and or tissue growth or for specific indications such as thrombosis. Antimicrobial agents such as broad spectrum antibiotics (Gentamycin sulphate, erythromycin or derivatized glycopeptides) which are slowly released into ;
the tissue can be applied in this manner to aid in combating clinical and sub-clinical infections in a surgical or trauma wound site.
To promote wound repair and/or tissue growth, one or more biologically active materials known to achieve either or both of these objectives can be applied to the ;
spiroid braided suture of the present invention. Such materials include any of several Human Growth Factors (HGDFs), magainin, tissue or kidney plasminogen activator to cause thrombosis, superoxide dismutase to scavenge tissue damaging free radicals, tumor necrosis factor for cancer therapy, colony stimulating factor, interferon, interleukin- -~ 2 or other lymphokine to enhance the immune system, and so forth.
~ ~ 2~
The term "Human Growth Factor" or "HGF" embraces those materials, known in the literature, which are referred ~ ~`
to as such and includes their biologically active closely related derivatives. The HGFs can be derived from naturally occurring sources including human and non-human sources, e.g., bovine sources, and are preferably produced by recombinant DNA techniques. Specifically, any of the HGFs which are mitogenically active and as such are effective in stimulating, accelerating, potentiating or otherwise enhancing the wound healing process can be usefully applied to the suture herein, e.g., hEGF (urogastrone), TGF-beta, IGF, PDGD, FGF, etc. These and other useful HGFs and `
closely related HGF derivatives, methods by which they can be obtained and methods and compositions featurlng the use of HGFs to enhance wound healing are variously disclosed, inter alia, in U.S. Patent Nos. 3,833,497, 3,917,824, 3,948,875, 4,338,397, ~,418,591, 4,528,186, 4,621,052, 4,743,679 and 4,717,717, European Patent Applications 0 046 039, 0 128 733, 0 131 868, 0 136 490, 0 147 178, 0 150 572, `
0 177 915 and 0 257 015, PCT International Applications WO
83/04030, W0 86/02271 and UK Patent Applications GB 2 092 155 A, 2 162 851 A and GB 2 172 890 A, all of which are incorporated by reference herein. of the known HGFs, hEGF, TGF-beta, IGF, PDGF, FGF are preferred.
This example illustrates the manufacture of a ;~
polypropylene multifilament yarn in accordance with the invention. The yarn was manufactured from a 96 percent isotactic polypropylene having a melt flow index of about 3.3 g/10 min, a weight average molecular weight of 283,000 and a number average weight of 61,000 as reported by the supplier (Resin F040A Natural of Aristech Chemical Corporation, Pittsburgh, PA).
';`'~.
2 ~
The condltions of melt spinning the polypropylene :~
multifilament yarn and the properties of the resulting yarn are set forth in Table XII below~
' "~ `""'~;````''" ~
.. . . :: ~,..
,' ' ' . ,~ ' ,' . ",:.'"
~: , ::, . . : ~
. ;
~ ' .
, . ~
~' , ""' ~',' ~'`'`''~
' ~
; .: . .... . .
TABLE XII
YARN MANUFACTURING CONDITIONS
A. Melt Spinninq Apparatus and Operating Conditions Operating Apparatus Component, Operating Condition Parameter `
Extruder barrel temp., zone 1 C 240 Extruder barrel temp., zone 2 C 260 Extruder barrel temp., zone 3 C 260 Extruder barrel pressure, psi1500 Extruder barrel melt temp., C 260 ~ ~-Pump size, cc per rev. 0.16 Pump temp., C 240 Pump pressure, psi 500-750 Pump melt temp., C 240 Block temp., C 240 Clamp temp., C 240 Adapter temp., ~C 240 ~`
Candle filter, screen, microns40 ;
No. of spinneret orifices 30 Diameter of spinneret orifices, .001 in 10 Spinneret temp., C 240 Spinneret pressure, psi 400-800 Spinneret melt temp., C 240 ~ ;
First palr of godets, C 65 First pair of godets, mpm 160 Second pair of godets, C 90 Second pair of godets, mpm 510 Draw (stretch) ratio 2.9 Third pair of godets, C ambient Third pair of godets, mpm 465 Shrinkage (relaxation), percent 9 35 wt% isopropyl Spin finish alcohol solution of Lurol 1187, as needed ' ` ' ;~
. ~
~ ~ ~ 5 ~
-28~
B. Properties of Polypropvlene Multifilament Yarn Denler per Filament 0.93 Filaments per Yarn 5,6,9,15,17,18,23,27,48 . ::
Denier per Yarn 5,6,8,14,16,17,21,25,45 These examples illustrate the manufacture of .
various sizes of braided suture in accordance with the structural parameters of U.S. Patent No. 5,019,093 employing the polypropylene multifilament yarn of Example 1. The structural parameters of the sutures are set forth in Table XII as follows:
TABLE XIII ~ ~:
CONSTRUCTION OF BRAIDED SUTURES
Overall Number of Denier of Denier Suture Suture Pick Sheath Individual of Example Denier Size Count Yarns Filaments Core 2 37 7/0 82 8 0.93 - :
3 67 6/0 75 12 0.93 -4 174 5/0 65 8 0.93 16 : :
254 4/0 75 12 0.93 62 :.
6 404 3/0 65 16 0.93 146 7 667 2/0 72 24 0.93 321 : :~
8 918 0 65 28 0.93 510 9 1384 1 65 32 0.93 907 These examples illustrate the manufacture of various sizes of braided suture possessing cabled cores as disclosed in PCT US 91/09137 and incorporating the ~ .
polypropylene multifilament yarn of Example 1. The cabled . .:~
core components of the sutures are constructed in accordance with parameters set forth in Table XIV as follows:
' ' ~ ' ~
., :
: ~ :
~ 2 ~
TABLE XIV
CABLED CORE CONSTRUCTION CHARACTERISTICS
First Twist Second In Twist No. Turns In No. of Denier of Per Turns : :~
Filame of Yarns Meter Per Cable nts In Individ In (appli Meter Coeffici d Examp The ual Each ed to (appli ent of Core .
le Core Yarns Plied the ed to Twist Denie In The Yarn plied form r Core yarn) the core) : X~
1048 x 7 43 7 305 250 32 907 `~ ~
x 3 ::
1127 x 7 24 7 534 409 40 510 x 3 ~ :
1217 x 7 15 7 583 447 35 321 :
x 3 1318 x 3 16 3 823 630 37 146 : ~.
x 3 Braided sutures are constructed around the cabled cores of Examples 10-13 in accordance with the parameters ;~
set forth in Table XV as follows~
TABLE XV
BRAIDED SUTURE CONSTRUCTION~CHARACTERISTICS
Denier of Individual `: :~
: Yarns Overa No.
I Core Sutur ll Pick of % of Braid L of e Sutur Count Sheat Sheat Core Core Angle I Examp Size e h h -~:- .;;
I le Denie Yarns r 1 1384 74 32 14 43 66 15.3 11 1/0 918 80 28 14 24 56 17.4 ::: : : :~
12 2/0 667 72 24 14 15 48 15.4 13 3/0 404 58 16 15 16 36 13.7 `
- -30~
These examples illustrate additional sutures containing a cabled core component as described in PCT/US
91/09137 and incorporating the polypropylene multifilament ~ ~
yarn of Example 1. :
The cabled cores of Examples 14-20 are constructed in accordance with the parameters set forth in Table XVI as follows: -,.
TABLE XVI :
CABLED CORE CONSTRUCTION CHARACTERISTICS
Back Front Twist Twist In Denier Denie In Turns No. of of r of Tota Turns Per Coeffic Filament Indivi Each l Per Meter ient Of Examp s In The dual Plied Core Meter To Back le Core Yarns Yarn Deni Applied Form Twist Iner To Each Cable CorePlied Core Yarn*
: ~ ~
1423 x 7 x 21 1501348 250 278 44.5 1548 x 7 x 45 312937 320 324 43.5 ;~
1627 x 7 x 25 176527 590 505 50.5 1717 x 7 x 16 111332 640 576 45.8 : ;:
1818 x 3 x 17 50 151 830 854 45.7 1923 x 1 x 21 21 64 1000 1035 36.3 :~
2017 x 1 x 16 16 47 1200 1200 36.0 :~
. * In Examples 19 and 20, only unplied yarn is used ;~
. .
.
Braided sutures are constructed around the cabled cores of Examples 14-20 in accordance with the parameters set forth in Table XVII as follows~
TABLE XVII
BRAIDED SUTURE CONSTRUCTION CHARACTERISTICS
Pick Overa Count No.
Core Sutur ll Picks of Denier of % of Braid of e Sutur Per Sheat Sheath / Core Angle Examp Size e Inch h Core le Denie Yarns r : -`
.. .:
18 3/0 404 6316 253 151 37 16 `~
~. , " '' "
These examples illustrate the manufacture of various sizes of spiroid braided suture in accordance with ;~
~ the structural parameters of U.S. Patent No. 5,059,213 i~
¦ employing the polypropylene multifilament yarn of Example 1.
¦ The structural parameters of the sutures are set forth in ~ .
Table XVIII as follows~
TABLE XVIII
CONSTRUCTION OF SPIROID BRAIDED SUTURES ~ ~
OverallDenier of : .:::
SutureNumber of Individual ExampleSuture DenierYarns Filaments `~
Size , : ;~
~` 2 1 ~ 3 ~
22 6/0 60 8 0.93 23 5/0 140 9 0.93 24 4/0 250 16 0.93 3/0 400 26 0.93 26 2/0 730 54 0.93 27 0(1/0) 1000 74 0.93 28 1 1580 117 0.93 29 2 2280 149 0.93 '.
' . ' ~ ,:
' ~;
The spiroid braided suture can be of "solid"
construction, i.e., a structure in which the filamentous material of its construction occupies substantially the entire cross-sectional area of the suture with a relatively -minor percentage of such area constituting void spaces or `
interstices between adjacent yarns and fibers, or it can possess a lumen, optionally occupied by a core component as in the braided cored suture of U.S. Patent No. 5,019,093, ~ `~
supra.
'..'`~" ~'"
(1) Suture Size (i.e., Suture Diameter) The suture size can be expressed in terms of ;-standard sizes, corresponding to certain ranges of diameter (in millimeters), as set forth in the United States Pharmaco~oeia (USP). Standard sizes of spiroid braided suture are set forth in Table VIII as follows~
TABLE VIII
SUTURE SIZE
USP Suture Size Diamater (mm) 2 0.50-0.599 1 0.40-0.499 0 (1/0) 0-35-0-399 2/0 0.30_0.399 3/o 0.20-0.249 4/o 0.15-0.199 5/0 0.10-0.149 6/0 0.070-o.ogg 7/0 0.050-0.069 8/0 0.~40-0.049 ; ~ 2 ~ ~ :J ~ ~ g (2) Overall Denler of the Suture The overall denier of the braided suture can vary from about 15 to about 4000. Within this range, the ranges of overall denier for particular sutures are: from about 15 to about 20 denier; from above about 20 to about 40 denier;
from above about 40 to about 70 denier; from above about 70 to about 180 denier; from above about 180 to about 300 denier; from above about 300 to about 450 denier; from above -about 450 to about 800 denier; from above about 800 to about ;~
1200 denier; from above about 1200 to about 1600 denier;
and, from above 1600 to 2500 denier.
(3) Pattern of the Interlocking Yarns Unlike the braided structure of U.S. Patent No.
5,019,093 where the yarns form a criss-cross pattern which may be thought of as confined to the surface of a hollow cylinder, a spiroid braided suture consists of a pattern of interlocking yarns which may be considered as extending from the surface of a cylinder to its center thus providing a solid structure as defined above. The characteristic -pattern of a spiroid braided suture is clearly different from that of the braided suture of U.S. Patent No.
5,019,093. In the former, the yarns are essentially parallel to the longitudinal axis of the suture whereas in the latter, the yarns cross over each other at some angle to the longitudinal axis of the suture.
(4) Pick Count Pick count is the number of stitches per inch lying in a single line parallel to the longitudinal axis of the suture as viewed from the surface of the suture.
Suitable pick counts can vary from 40-80 stitches/inch and preferably from 50-70 stitches/inch.
(5) The Number of Yarns ' ~, ' , . ' ' :' ., ' ' l 3 ~
The number of yarns employed in the construction of the spiroid braided suture bears some relation to overall suture denier, the number of yarns generally increasing with ~ .
the weight of the suture. Thus, across the range of suture weight (denier) indicated above, a spiroid braided suture can be fabricated with from about 6 up to as many as about 30 individùal yarns constructed from individual filaments having the deniers discussed belo~
Table IX below sets forth broad and preferred ranges for the numbers of yarns which are suitable for the construction of spiroid braided sutures of various ranges of :~
overall denier. The deniers of individual filaments in a yarn can vary from about 0.2 to about 6.0 for the broad range of number of yarns and the deniers of individual :.
filaments can vary from about 0.6 to about 3.0, and advantageously from about 0.8 to about 2.5, for the preferred range of number of yarns.
TABLE IX :
NUMBER OF YARNS RELATED TO SUTURE DENIER
Number of Number of Yarns Yarns :~
Overall SutureSuture(Broad (Preferred Denier Size Range) Range) .
from about 15 to7/0, 8/03-12 3-6 about 40 greater than about 6/0 6-15 6-12 ~.
40 to about 70 greater than about 5/0 6-15 6-12 70 to about 180 greater than about 4/0 6-26 9-22 180 to about 300 greater than about 3/0 20-36 24-32 300 to about 450 greater than about 2/0 40-58 46-54 450 to about 800 2 ~ .L ~ 8 greater than about 0 60-80 66-74 800 to about 1200 greater than about 1,2 84-170 88-164 1200 to about 2500 While the yarns need not be twisted, it is generally preferred that they be provided with a slight twist so as to minimize snagging during construction.
(6) Individual Filament Denier The individual filaments comprising each yarn can vary in weight from about 0.2 to about 6.0 denier, preferably from about 0.6 to about 3.0 denier and more preferably from about 0.8 to about 2.5 denier. The number of such filaments present in a particular yarn will depend `
on the overall denier of the suture as well as the number of yarns utilized in the construction of the suture. Table X
sets forth some typical numbers of filaments per yarn for both the broad and pre~erred ranges of filament weight~
TABLE X
NUMBER OF FILAMENTS PER YARN
Approximate ApproximateFilamer.t Miniumum Maximum Denier 23 135 0.2 9 54 0.5 o.g 3 15 1.8 -~
l 5 6.0 ~'~
(7) Core (Optional) For all but the smallest sizes of spiroid braided suture, the suture, although substantially solid in the sense defined above, can optionally contain some small amount of void space, generally not exceeding 25% or so in the larger sutures sizes, which, if desired, can be 2~ 3.
." ~, " ,.
partially or substantially completely filled with a core component. A core may be advantageous where it is desired to increase the density of the suture and/or preserve its roundness. The core, where present, can be monofilamentous or multifilamentous. In the case of the latter, the core itself can be braided or can be provided with some other configuration such as a twist, ply, cable, etc. Preferably, the core is a cabled core of the type disclosed in PCT/US
91/09137, discussed supra.
Table XI below provides some typical core deniers for spiroid braided sutures of various deniers:
TABLE XI
CORE DENIER RELATED TO SUTURE DENIER
- Maximum Denier ofMaximum Denier Overall Suture Suture Optional of Optional Core Denier Size Core (Broad(Preferred Range) Range) :.
from about 15 to 8/0, 7/0 none none about 40 greater than about 6/0 none none 40 to about 70 greater than about 5/0 25-65 35-55 70 to about 180 greater than about 4/0 40-80 50-70 180 to about 300 greater than about 3/0 120-170 130-160 300 to about 450 greater than about 2/0 290-340 310-330 450 to about 800 greater than about 0 450-550 470-530 800 to about 1200 greater than about 1,2 800-1600 850-1500 1200 to about 2500 -21~ 31 ~
' :
It can be advantageous to apply one or more coating compositions to a braided suture manufactured with the polypropylene multifilament yarn of this invention in order to improve one or more of its properties such as surface lubricity and knot tiedown behavior. A variety of suture coating compositions proposed for either or both purposes is known in the art, e.g., those disclosed in U.S.
Patent No. 4,047,533, the contents of which are incorporated i by reference herein. -~
It is also within the scope of this invention to impregnate the suture with, or otherwise apply thereto, one or more medico-surgically useful substances, e.g.; those which accelerate or beneficially modify the healing process when the suture is applied to a wound or surgical site. So, for example, the braided suture can be provided with a therapeutic agent which will be deposited at the sutured site. The therapeutic agent can be chosen for its i antimicrobial properties, capability for promoting wound repair and or tissue growth or for specific indications such as thrombosis. Antimicrobial agents such as broad spectrum antibiotics (Gentamycin sulphate, erythromycin or derivatized glycopeptides) which are slowly released into ;
the tissue can be applied in this manner to aid in combating clinical and sub-clinical infections in a surgical or trauma wound site.
To promote wound repair and/or tissue growth, one or more biologically active materials known to achieve either or both of these objectives can be applied to the ;
spiroid braided suture of the present invention. Such materials include any of several Human Growth Factors (HGDFs), magainin, tissue or kidney plasminogen activator to cause thrombosis, superoxide dismutase to scavenge tissue damaging free radicals, tumor necrosis factor for cancer therapy, colony stimulating factor, interferon, interleukin- -~ 2 or other lymphokine to enhance the immune system, and so forth.
~ ~ 2~
The term "Human Growth Factor" or "HGF" embraces those materials, known in the literature, which are referred ~ ~`
to as such and includes their biologically active closely related derivatives. The HGFs can be derived from naturally occurring sources including human and non-human sources, e.g., bovine sources, and are preferably produced by recombinant DNA techniques. Specifically, any of the HGFs which are mitogenically active and as such are effective in stimulating, accelerating, potentiating or otherwise enhancing the wound healing process can be usefully applied to the suture herein, e.g., hEGF (urogastrone), TGF-beta, IGF, PDGD, FGF, etc. These and other useful HGFs and `
closely related HGF derivatives, methods by which they can be obtained and methods and compositions featurlng the use of HGFs to enhance wound healing are variously disclosed, inter alia, in U.S. Patent Nos. 3,833,497, 3,917,824, 3,948,875, 4,338,397, ~,418,591, 4,528,186, 4,621,052, 4,743,679 and 4,717,717, European Patent Applications 0 046 039, 0 128 733, 0 131 868, 0 136 490, 0 147 178, 0 150 572, `
0 177 915 and 0 257 015, PCT International Applications WO
83/04030, W0 86/02271 and UK Patent Applications GB 2 092 155 A, 2 162 851 A and GB 2 172 890 A, all of which are incorporated by reference herein. of the known HGFs, hEGF, TGF-beta, IGF, PDGF, FGF are preferred.
This example illustrates the manufacture of a ;~
polypropylene multifilament yarn in accordance with the invention. The yarn was manufactured from a 96 percent isotactic polypropylene having a melt flow index of about 3.3 g/10 min, a weight average molecular weight of 283,000 and a number average weight of 61,000 as reported by the supplier (Resin F040A Natural of Aristech Chemical Corporation, Pittsburgh, PA).
';`'~.
2 ~
The condltions of melt spinning the polypropylene :~
multifilament yarn and the properties of the resulting yarn are set forth in Table XII below~
' "~ `""'~;````''" ~
.. . . :: ~,..
,' ' ' . ,~ ' ,' . ",:.'"
~: , ::, . . : ~
. ;
~ ' .
, . ~
~' , ""' ~',' ~'`'`''~
' ~
; .: . .... . .
TABLE XII
YARN MANUFACTURING CONDITIONS
A. Melt Spinninq Apparatus and Operating Conditions Operating Apparatus Component, Operating Condition Parameter `
Extruder barrel temp., zone 1 C 240 Extruder barrel temp., zone 2 C 260 Extruder barrel temp., zone 3 C 260 Extruder barrel pressure, psi1500 Extruder barrel melt temp., C 260 ~ ~-Pump size, cc per rev. 0.16 Pump temp., C 240 Pump pressure, psi 500-750 Pump melt temp., C 240 Block temp., C 240 Clamp temp., C 240 Adapter temp., ~C 240 ~`
Candle filter, screen, microns40 ;
No. of spinneret orifices 30 Diameter of spinneret orifices, .001 in 10 Spinneret temp., C 240 Spinneret pressure, psi 400-800 Spinneret melt temp., C 240 ~ ;
First palr of godets, C 65 First pair of godets, mpm 160 Second pair of godets, C 90 Second pair of godets, mpm 510 Draw (stretch) ratio 2.9 Third pair of godets, C ambient Third pair of godets, mpm 465 Shrinkage (relaxation), percent 9 35 wt% isopropyl Spin finish alcohol solution of Lurol 1187, as needed ' ` ' ;~
. ~
~ ~ ~ 5 ~
-28~
B. Properties of Polypropvlene Multifilament Yarn Denler per Filament 0.93 Filaments per Yarn 5,6,9,15,17,18,23,27,48 . ::
Denier per Yarn 5,6,8,14,16,17,21,25,45 These examples illustrate the manufacture of .
various sizes of braided suture in accordance with the structural parameters of U.S. Patent No. 5,019,093 employing the polypropylene multifilament yarn of Example 1. The structural parameters of the sutures are set forth in Table XII as follows:
TABLE XIII ~ ~:
CONSTRUCTION OF BRAIDED SUTURES
Overall Number of Denier of Denier Suture Suture Pick Sheath Individual of Example Denier Size Count Yarns Filaments Core 2 37 7/0 82 8 0.93 - :
3 67 6/0 75 12 0.93 -4 174 5/0 65 8 0.93 16 : :
254 4/0 75 12 0.93 62 :.
6 404 3/0 65 16 0.93 146 7 667 2/0 72 24 0.93 321 : :~
8 918 0 65 28 0.93 510 9 1384 1 65 32 0.93 907 These examples illustrate the manufacture of various sizes of braided suture possessing cabled cores as disclosed in PCT US 91/09137 and incorporating the ~ .
polypropylene multifilament yarn of Example 1. The cabled . .:~
core components of the sutures are constructed in accordance with parameters set forth in Table XIV as follows:
' ' ~ ' ~
., :
: ~ :
~ 2 ~
TABLE XIV
CABLED CORE CONSTRUCTION CHARACTERISTICS
First Twist Second In Twist No. Turns In No. of Denier of Per Turns : :~
Filame of Yarns Meter Per Cable nts In Individ In (appli Meter Coeffici d Examp The ual Each ed to (appli ent of Core .
le Core Yarns Plied the ed to Twist Denie In The Yarn plied form r Core yarn) the core) : X~
1048 x 7 43 7 305 250 32 907 `~ ~
x 3 ::
1127 x 7 24 7 534 409 40 510 x 3 ~ :
1217 x 7 15 7 583 447 35 321 :
x 3 1318 x 3 16 3 823 630 37 146 : ~.
x 3 Braided sutures are constructed around the cabled cores of Examples 10-13 in accordance with the parameters ;~
set forth in Table XV as follows~
TABLE XV
BRAIDED SUTURE CONSTRUCTION~CHARACTERISTICS
Denier of Individual `: :~
: Yarns Overa No.
I Core Sutur ll Pick of % of Braid L of e Sutur Count Sheat Sheat Core Core Angle I Examp Size e h h -~:- .;;
I le Denie Yarns r 1 1384 74 32 14 43 66 15.3 11 1/0 918 80 28 14 24 56 17.4 ::: : : :~
12 2/0 667 72 24 14 15 48 15.4 13 3/0 404 58 16 15 16 36 13.7 `
- -30~
These examples illustrate additional sutures containing a cabled core component as described in PCT/US
91/09137 and incorporating the polypropylene multifilament ~ ~
yarn of Example 1. :
The cabled cores of Examples 14-20 are constructed in accordance with the parameters set forth in Table XVI as follows: -,.
TABLE XVI :
CABLED CORE CONSTRUCTION CHARACTERISTICS
Back Front Twist Twist In Denier Denie In Turns No. of of r of Tota Turns Per Coeffic Filament Indivi Each l Per Meter ient Of Examp s In The dual Plied Core Meter To Back le Core Yarns Yarn Deni Applied Form Twist Iner To Each Cable CorePlied Core Yarn*
: ~ ~
1423 x 7 x 21 1501348 250 278 44.5 1548 x 7 x 45 312937 320 324 43.5 ;~
1627 x 7 x 25 176527 590 505 50.5 1717 x 7 x 16 111332 640 576 45.8 : ;:
1818 x 3 x 17 50 151 830 854 45.7 1923 x 1 x 21 21 64 1000 1035 36.3 :~
2017 x 1 x 16 16 47 1200 1200 36.0 :~
. * In Examples 19 and 20, only unplied yarn is used ;~
. .
.
Braided sutures are constructed around the cabled cores of Examples 14-20 in accordance with the parameters set forth in Table XVII as follows~
TABLE XVII
BRAIDED SUTURE CONSTRUCTION CHARACTERISTICS
Pick Overa Count No.
Core Sutur ll Picks of Denier of % of Braid of e Sutur Per Sheat Sheath / Core Angle Examp Size e Inch h Core le Denie Yarns r : -`
.. .:
18 3/0 404 6316 253 151 37 16 `~
~. , " '' "
These examples illustrate the manufacture of various sizes of spiroid braided suture in accordance with ;~
~ the structural parameters of U.S. Patent No. 5,059,213 i~
¦ employing the polypropylene multifilament yarn of Example 1.
¦ The structural parameters of the sutures are set forth in ~ .
Table XVIII as follows~
TABLE XVIII
CONSTRUCTION OF SPIROID BRAIDED SUTURES ~ ~
OverallDenier of : .:::
SutureNumber of Individual ExampleSuture DenierYarns Filaments `~
Size , : ;~
~` 2 1 ~ 3 ~
22 6/0 60 8 0.93 23 5/0 140 9 0.93 24 4/0 250 16 0.93 3/0 400 26 0.93 26 2/0 730 54 0.93 27 0(1/0) 1000 74 0.93 28 1 1580 117 0.93 29 2 2280 149 0.93 '.
' . ' ~ ,:
' ~;
Claims (31)
1. A polypropylene multifilament yarn produced by the process which comprises melt spinning an isotactic polypropylene employing an extruder equipped with a spinneret and downstream of the extruder a draw frame possessing three pairs of godets, the extruder being operated in one or more zones thereof at a temperature of from about 230 to about 270°C, the pressure of the extruder being from about 1000 to about 2000 psi, the temperature of the spinneret being from about 220 to about 250°C, the first pair of godets being operated at a temperature of from about 40 to about 90°C and an mpm of from about 100 to about 300, the second pair of godets being operated at a temperature of from about 70 to about 130°C and an mpm of from about 300 to about 1000 and the third pair of godets being operated at ambient temperature and an mpm of from about 250 to about 1000, the draw ratio of the yarn being from about 2 to about 4 and the shrinkage of the yarn being from about 5 to about 15 percent.
2. The yarn of Claim 1 wherein the polypropylene is an isotactic polypropylene resin having a melt flow index, g/10 min, of from about 2 to about 6.
3. The yarn of Claim 1 wherein the polypropylene is an isotactic polypropylene resin having a melt flow index, g/10 min, of from about 2.1 to about 5Ø
4. The yarn of Claim 1 wherein the polypropylene is an isotactic polypropylene resin having a melt flow index, g/10 min, of from about 2.5 to about 4.6.
5. The yarn of Claim 1 made from filaments of from about 0.2 to about 6 denier, constructed with from about 3 to about 200 filaments and possessing a denier of from about 0.6 to about 1200.
6. The yarn of Claim 1 made from filaments of from about 0.6 to about 3.0 denier, constructed with from about 5 to about 100 filaments and possessing a denier of from about 3 to about 300.
7. The yarn of Claim 1 made from filaments of from about 0.8 to about 2.5 denier, constructed with from about 5 to about 70 filaments and possessing a denier of from about 4 to about 175.
8. A suture constructed with a polypropylene multifilament yarn produced by the process which comprises melt spinning an isotactic polypropylene employing an extruder equipped with a spinneret and downstream of the extruder a draw frame possessing three pairs of godets, the extruder being operated in one or more zones thereof at a temperature of from about 230 to about 270°C, the pressure of the extruder being from about 1000 to about 2000 psi, the temperature of the spinneret being from about 220 to about 250°C, the first pair of godets being operated at a temperature of from about 40 to about 90°C and an mpm of from about 100 to about 300, the second pair of godets being operated at a temperature of from about 70 to about 130°C
and an mpm of from about 300 to about 1000 and the third pair of godets being operated at ambient temperature and an mpm of from about 250 mpm to about 1000, the draw ratio of the yarn being from about 2 to about 4 and the shrinkage of the yarn being from about 5 to about 15 percent.
and an mpm of from about 300 to about 1000 and the third pair of godets being operated at ambient temperature and an mpm of from about 250 mpm to about 1000, the draw ratio of the yarn being from about 2 to about 4 and the shrinkage of the yarn being from about 5 to about 15 percent.
9. The suture of Claim 8 wherein the polypropylene is an isotactic polypropylene resin having a melt flow index, g/10 min, of from about 2 to about 6.
10. The suture of Claim 8 wherein the polypropylene is an isotactic polypropylene resin having a melt flow index, g/10 min, of from about 2.1 to about 5Ø
11. The suture of Claim 8 wherein the polypropylene is an isotactic polypropylene resin having a melt flow index, g/10 min, of from about 2.5 to about 4.6.
12. The suture of Claim 8 made from filaments of from about 0.2 to about 6 denier, constructed with from about 3 to about 200 filaments and possessing a denier of from about 0.6 to about 1200.
13. The suture of Claim 8 made from filaments of from about 0.6 to about 3 denier, constructed with from about 5 to about 100 filaments and possessing a denier of from about 3 to about 300.
14. The suture of Claim 8 made from filaments of from about 0.8 to about 2.5 denier, constructed with from about 5 to about 70 filaments and possessing a denier of from about 4 to about 175.
15. The suture of claim 8 of braided construction.
16. The suture of Claim 15 wherein for a given range of overall suture denier, the range of pick count, number of sheath yarns and denier of individual filaments comprising a sheath yarn are related to each other as follows:
17. The suture of Claim 15 wherein for a given overall suture denier, the range of pick count, number of sheath yarns and denier of individual filaments comprising a sheath yarn are related to each other as follows:
18. The suture of Claim 15 possessing a core.
19. The suture of Claim 15 possessing a cabled core.
20. The suture of Claim 15 possessing a cabled core surrounded by a sheath, wherein for a given range of overall suture denier, the range of pick count, number of sheath yarns, denier of individual filaments contained in a sheath yarn and denier of the cabled core are related to each other as follows:
21. The suture of Claim 15 possessing a cabled core surrounded by a sheath, wherein for a given overall suture denier, the range of pick count, number of sheath yarns, denier of individual filaments comprising a sheath yarn and denier of the cabled core are related to each other as follows:
22. The suture of claim 20, wherein the cabled core is constructed with a coefficient of twist of at least about 24.
23. The suture of Claim 20, wherein the cabled core is constructed from a plurality of individual yarns possessing a first twist of from about 100 to about 1500 turns per meter, the twisted yarns being assembled into a core possessing a second, opposite twist of from about 100 to about 1200 turns per meter.
24. The suture of Claim 20, wherein the coefficient of twist of the cabled core, alpha, is determined from the equation:
where:
K = twist level in turns per meter; and D = denier of said core.
where:
K = twist level in turns per meter; and D = denier of said core.
25. The suture of Claim 23, wherein the twisted yarns are plied prior to application of the second twist.
26. The suture of Claim 8 of solid spiroid braid construction.
27. The suture of Claim 26 wherein for a given overall suture denier, the number of yarns and denier of individual filaments comprising a yarn are related to each other as follows:
28. The suture of Claim 26 wherein for a given overall suture denier, the number of yarns and denier of individual filaments comprising a yarn are related to each other as follows:
29. The suture of Claim 26 possessing a core.
30. The suture of Claim 26 possessing a core, the maximum denier of the core for a given overall suture denier being as follows:
31. The suture of Claim 26 possessing a core, the maximum denier of the core for a given overall suture denier being as follows:
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US1536893A | 1993-02-09 | 1993-02-09 | |
| US08/015,368 | 1993-02-09 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2115108A1 true CA2115108A1 (en) | 1994-08-10 |
Family
ID=21770998
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002115108A Abandoned CA2115108A1 (en) | 1993-02-09 | 1994-02-07 | Polypropylene multifilament yarn and suture manufactured therefrom |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2115108A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6264674B1 (en) | 1998-11-09 | 2001-07-24 | Robert L. Washington | Process for hot stretching braided ligatures |
-
1994
- 1994-02-07 CA CA002115108A patent/CA2115108A1/en not_active Abandoned
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6264674B1 (en) | 1998-11-09 | 2001-07-24 | Robert L. Washington | Process for hot stretching braided ligatures |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Discontinued | ||
| FZDE | Discontinued |
Effective date: 20000207 |