Colored suture

Abstract

Suture containing filaments of ultra-high molecular weight polyethylene (UHMwPE), characterized in that the suture contains a multi-filament yarn that is obtained by a process comprising the steps of: a) Providing a mixture containing UHMwPE, a spinning solvent and a pigment b) Spinning a multi-filament yarn from the mixture by the gel spinning process.

Claims

1. A colored multi-filament yarn comprising filaments that have been obtained by gel spinning a mixture containing ultra-high molecular weight polyethylene (UHMwPE) having an intrinsic viscosity (IV) of between about 8 and 40 dl/g, a spin solvent and a pigment, and wherein the filaments consist of UHMwPE, between 0.1 and 7.0 wt. % of an inorganic chromium oxide-containing pigment, a residual amount of spin solvent of less than about 500 ppm, and less than 1000 ppm of further constituents.

2. The multi-filament yarn according to claim 1, wherein the amount of the inorganic pigment present in the filaments is between 0.3 and 5.0 wt. %.

3. The multi-filament yarn according to claim 1, wherein the amount of the inorganic pigment present in the filaments is lower than 2.0 wt. %.

4. The multi-filament yarn according to claim 1, wherein the inorganic pigment is aluminum-chromium-cobalt oxide.

5. The multi-filament yarn according to claim 1, wherein the residual amount of spin solvent is less than 250 ppm.

6. The multi-filament yarn according to claim 1, wherein the residual amount of spin solvent is less than 100 ppm.

7. The multi-filament yarn according to claim 1, wherein the residual amount of spin solvent is less than 60 ppm.

8. The multi-filament yarn according to claim 1, wherein the filaments contain less than 500 ppm of further constituents.

9. The multi-filament yarn according to claim 1, wherein the number of filaments is between 10 and 1000.

Description

EXAMPLES 1-4

(1) Slurries containing decalin, 6 mass % of powder of UHMwPE having an IV of 14 and 0.5, 1, 1.5 respectively 2 wt. % of aluminum-chromium-cobalt oxide pigment (of the cations is 32.5% Co, 32% Al and 35.5 Cr) were prepared in a mixer.

(2) The slurries were fed to a twin screw extruder having a diameter of 25 mm, being equipped with a gear-pump at a temperature setting of 180 C. In the extruder the UHMwPE was dissolved in the decalin and the so obtained mixture of the UHMwPE dissolved in the decalin and the pigment was extruded through a spin plate having 24 spin holes into a nitrogen atmosphere with a rate of 1.0 g/min per hole. The so obtained solution filaments were cooled in a water bath kept at about 35 C. and with a water flow rate of about 5 cm/s perpendicular to the filaments entering the bath, and taken-up at such rate that a draw ratio of 15 was applied to the as-spun filaments in the air-gap of 15 mm. The filaments subsequently entered an oven at 130 C. The filaments were further stretched, during which process the decalin evaporated from the filaments. After the stretching process the filaments were kept taut in an oxygen free environment for 24 hours at 100 C.

(3) Mechanical properties, leaching out and cytotoxicity were determined on the so obtained multi-filament yarns.

(4) The mechanical properties are reported in table 1. Favourable mechanical properties were obtained.

(5) No compounds related to pigment, or other unknown compounds, where found. The pigment <10 g/kg (<10 ppb).

(6) From these results it can be concluded that the bio-availability of pigment due to leaching from sutures according to the invention containing the multi-filament yarn is negligible.

(7) All the extracts of the colored samples when submitted to the cytotoxicity test exhibited no reactivity (grade 0) by the cell cultures. Severe reactivity (grade 4) was observed for the positive control article. The negative control article showed no signs of reactivity (grade 0). Therefore it can be concluded that sutures according to the invention containing the multi-filament yarn are non-cytotoxic.

(8) The yarns furthermore show a homogeneous and bright colour.

Comparative Test A

(9) Multi-filament yarn was produced according to examples 1-4, however no pigment was used.

(10) The multi-filament yarn was dyed with D&C blue No 6 (delivered by Sigma Aldrich of the USA) by placing the multi-filament yarn for 7 hours at 120 C. in a solution of the dye in super-critical carbon dioxide.

(11) The resulting yarns presented a non-homogeneous color distribution pattern.

(12) Mechanical properties and leaching out were determined.

(13) Mechanical properties are reported in table 1. A serious decline in mechanical properties was observed (tenacity decreased about 40%).

(14) Considerable leaching out took place in coconut oil as was already clear from the disappearing color of the multi-filament yarn.

(15) From these results it is clear that sutures containing the multi-filament yarn according to comparative test A are not suitable for use in surgery.

Comparative Test B

(16) Multi-filament yarn was produced according to examples 1-4, however no pigment was used.

(17) The multi-filament yarn was dip-coated with a polyurethane coating containing an azo-dye (Sudan Red D, delivered by Sigma Aldrich).

(18) Test data of the multi-filament yarn were measured and reported in table I. It is clear that considerable leaching out took place and that the cyto-toxicity of the filaments is insufficient. Therefore sutures containing the multi-filament yarn according to comparative test B are not suitable for use in surgery.

(19) TABLE-US-00001 TABLE 1 Example/ Tenacity Modulus leach- Xomp. [cN/ [cN/ Eab ing cytotox. colouring exp. dTex] dTex] [%] [-] [-] [-] I 37 1439 2.8 No 0 homogeneous II 37 1377 2.9 No 0 Homogeneous III 40 1501 3.0 No 0 Homogeneous IV 37 1414 2.9 No 0 Homogeneous A 21 Yes In- homogeneous B 37 1381 2.8 Yes In- homogeneous