Process for producing high knot strength polyamide monofilaments

Claim 2

In a process for producing a polyamide monofilament having high knot strength, the steps which comprise: (A) drawing melt spun undrawn polyamide monofilament (M 1 ) at a ratio of about 3-5.5 to produce a partially oriented monofilament (M 2 ) having a diameter of about 0.05-2 mm; (B) subjecting said monofilament (M 2 ) to saturated steam having a pressure not less than about 1 kg/cm 2 .G for about 0.05-5 seconds while relaxing to produce a monofilament (M 3 ) relaxed to about 0.7-1.0 times the length of said partially oriented monofilament (M 2 ); and (C) heating said monofilament (M 3 ) in the presence of (a) a gas at about 200°-800° C. and (b) a liquid at about 150°-265° C., said gas and said liquid being inert to said monofilament (M 3 ) for about 0.05-5 seconds and drawing said relaxed monofilament (M 3 ) at a ratio of about 1.2-2.5 to produce a drawn monofilament (M 4 ).

Claim 3

In a process for producing a polyamide monofilament having high knot strength, the steps which comprise: (A) drawing melt spun undrawn polyamide monofilament (M 1 ) at a ratio of about 3-5.5 to produce a partially oriented monofilament (M 2 ) having a diameter of about 0.05-2 mm; (b) subjecting said monofilament (M 2 ) to saturated steam having a pressure not less than about 1 kg/cm 2 ·G for about 0.05-5 seconds while relaxing to produce a monofilament (M 3 ) relaxed to about 0.7-1.0 times the length of said partially oriented monofilament (M 2 ); and (C) heating said monofilament (M 3 ) in the presence of a gas at about 200°-800° C., said gas being inert to said monofilament (M 3 ) for about 0.05-5 seconds and drawing said relaxed monofilament (M 3 ) at a ratio of about 1.2-2.5 to produce a drawn monofilament (M 4 ).

Claim 4

In a process for producing a polyamide monofilament having high knot strength, the steps which comprise: (A) drawing melt spun undrawn polyamide monofilament (M 1 ) at a ratio of about 3-5.5 to produce a partially oriented monofilament (M 2 ) having a diameter of about 0.05-2 mm; (b) subjecting said monofilament (M 2 ) to saturated steam having a pressure not less than about 1 kg/cm 2 ·G for about 0.05-5 seconds while relaxing to produce a monofilament (M 3 ) relaxed to about 0.7-1.0 times the length of said partially oriented monofilament (M 2 ); and (C) heating said monofilament (M 3 ) in the presence of a gas at about 200°-800° C., said gas being inert to said monofilament (M 3 ) for about 0.05-5 seconds and drawing said relaxed monofilament (M 3 ) at a ratio of about 1.2-2.5 to produce a drawn monofilament (M 4 ).

Claim 5

In a process for producing a polyamide monofilament having high knot strength, the steps which comprise: (A) drawing melt spun undrawn polyamide monofilament (M 1 ) at a ratio of about 3-5.5 to produce a partialy oriented monofilament (M 2 ) having a diameter of about 0.05-2 mm: (B) subjecting said monofilament (M 2 ) to saturated steam having a pressure not less than about 1 kg/cm 2 ·G for about 0.05-5 seconds while relaxing to produce a monofilament (M 3 ) relaxed to about 0.7-1.0 times the length of said partially oriented monofilament (M 2 ); and (C) heating said monofilament (M 3 ) in the presence of a liquid at about 150°-265° C., said liquid being inert to said monofilament (M 3 ) for about 0.05-5 seconds and drawing said relaxed monofilament (M 3 ) at a ratio of about 1.2-2.5 to produce a drawn monofilament (M 4 ).

Claim 6

In a process for producing a polyamide monofilament having high knot strength, the steps which comprise: (A) drawing melt spun undrawn polyamide monofilament (M 1 ) at a ratio of about 3-5.5 to produce a partialy oriented monofilament (M 2 ) having a diameter of about 0.05-2 mm: (B) subjecting said monofilament (M 2 ) to saturated steam having a pressure not less than about 1 kg/cm 2 ·G for about 0.05-5 seconds while relaxing to produce a monofilament (M 3 ) relaxed to about 0.7-1.0 times the length of said partially oriented monofilament (M 2 ); and (C) heating said monofilament (M 3 ) in the presence of a liquid at about 150°-265° C., said liquid being inert to said monofilament (M 3 ) for about 0.05-5 seconds and drawing said relaxed monofilament (M 3 ) at a ratio of about 1.2-2.5 to produce a drawn monofilament (M 4 ).

Claim 7

A process according to claim 1, 2 or 3 wherein said inert gas is air.

Claim 8

In a process for producing a polyamide monofilament having high knot strength, the steps which comprise: (A) drawing melt spun undrawn polyamide monofilament (M 1 ) at a ratio of about 3-5.5 to produce a partially oriented monofilament (M 2 ) having a diameter of about 0.05-2 mm; (B) passing said monofilament (M 2 ) through a pressure chamber filled with saturated steam having a pressure not less than about 1 kg/cm 3 ·G for about 0.05-5 seconds while relaxing to produce a monofilament (M 3 ) relaxed to about 0.7-1.0 times the length of said partially oriented monofilament (M 2 ); and (C) heating said monofilament (M 3 ) in the presence of a gas at about 200°-800° C. for about 0.05-5 seconds simultaneously with drawing said relaxed monofilament (M 3 ) at a ratio of about 1.2-2.5 to produce a drawn monofilament (M 4 ), said gas being inert to said monofilament (M 3 ).

Claim 9

In a process for producing a polyamide monofilament having high knot strength, the steps which comprise: (A) drawing melt spun undrawn polyamide monofilament (M 1 ) at a ratio of about 3-5.5 to produce a partially oriented monofilament (M 2 ) having a diameter of about 0.05-2 mm; (B) passing said monofilament (M 2 ) through a pressure chamber filled with saturated steam having a pressure not less than about 1 kg/cm 3 ·G for about 0.05-5 seconds while relaxing to produce a monofilament (M 3 ) relaxed to about 0.7-1.0 times the length of said partially oriented monofilament (M 2 ); and (C) heating said monofilament (M 3 ) in the presence of a gas at about 200°-800° C. for about 0.05-5 seconds simultaneously with drawing said relaxed monofilament (M 3 ) at a ratio of about 1.2-2.5 to produce a drawn monofilament (M 4 ), said gas being inert to said monofilament (M 3 ).

Claim 10

A process according to claim 1, 2, 3 or 5, wherein said polyamide is a polycapramide homopolymer.

Claim 11

A process according to claim 1, 2, 3 or 5, wherein said polyamide is copolyamide and wherein at least 85% of the total weight thereof is occupied by a polycapramide component.

Claim 12

A process according to claim 1, 2, 3 or 5, wherein said polyamide is blended polyamide, and wherein at least about 85% of the total weight thereof comprises polycapramide.

Claim 13

A process for producing polyamide monofilament having a cross-sectional structure comprising a two-layer structure consisting of a core and a skin layer, an average index of birefringence of at least about 50×10 -3 and a degree of molecular orientation in the amorphous region of said skin layer of not more than about 0.5, which process comprises the steps of: (A) drawing melt spun undrawn polyamide monofilament (M 1 ) at a ratio of about 3-5.5 to produce a partially oriented monofilament (M 2 ) having a diameter of about 0.05-2 mm; (B) passing said monofilament (M 2 ) through a pressure chamber filled with saturated steam having a pressure not less than about 1 kg/cm 2 ·G for about 0.05-5 seconds to prepare a relaxed monofilament (M 3 ) relaxed to 0.7-1.0 times the length of said partially oriented monofilament (M 2 ); (C) passing said monofilament (M 3 ) through a heating zone containing: (a) a gas at about 200°-800° C. and (b) a liquid at about 150°-265° C. that are inert to said monofilament (M 3 ) for about 0.05-5 seconds and drawing said relaxed monofilament (M 3 ) to about 1.2-2.5 times the length of said relaxed monofilament (M 3 ) to produce a drawn monofilament (M 4 ); and (D) passing said drawn monofilament (M 4 ) through a hot water zone containing hot water at about 50°-97° C. for about 0.05-20 seconds and relaxing said monofilament (M 4 ) to about 0.9-1.0 times the length of said drawn monofilament (M 4 ) to produce a heatset monofilament (M 5 ).

Claim 14

A process for producing polyamide monofilament having a cross-sectional structure comprising a two-layer structure consisting of a core and a skin layer, an average index of birefringence of at least about 50×10 -3 and a degree of molecular orientation in the amorphous region of said skin layer of not more than about 0.5, which process comprises the steps of: (A) drawing melt spun undrawn polyamide monofilament (M 1 ) at a ratio of about 3-5.5 to produce a partially oriented monofilament (M 2 ) having a diameter of about 0.05-2 mm; (B) passing said monofilament (M 2 ) through a pressure chamber filled with saturated steam having a pressure not less than about 1 kg/cm 2 ·G for about 0.05-5 seconds to prepare a relaxed monofilament (M 3 ) relaxed to 0.7-1.0 times the length of said partially oriented monofilament (M 2 ); (C) passing said monofilament (M 3 ) through a heating zone containing: (a) a gas at about 200°-800° C. and (b) a liquid at about 150°-265° C. that are inert to said monofilament (M 3 ) for about 0.05-5 seconds and drawing said relaxed monofilament (M 3 ) to about 1.2-2.5 times the length of said relaxed monofilament (M 3 ) to produce a drawn monofilament (M 4 ); and (D) passing said drawn monofilament (M 4 ) through a hot water zone containing hot water at about 50°-97° C. for about 0.05-20 seconds and relaxing said monofilament (M 4 ) to about 0.9-1.0 times the length of said drawn monofilament (M 4 ) to produce a heatset monofilament (M 5 ).

Claim 15

A process for producing polyamide monofilament having a cross-sectional structure comprising a two-layer structure consisting of a core and a skin layer, an average index of birefringence of at least about 50×10 -3 and a degree of molecular orientation in the amorphous region of said skin layer of not more than about 0.5, which process comprises the steps of: (A) drawing melt spun undrawn polyamide monofilament (M 1 ) at a ratio of about 3-5.5 to produce a partially oriented monofilament (M 2 ) having a diameter of about 0.05-2 mm; (B) passing said monofilament (M 2 ) through a pressure chamber filled with saturated steam having a pressure not less than about 1 kg/cm 2 ·G for about 0.05-5 seconds to prepare a relaxed monofilament (M 3 ) relaxed to 0.7-1.0 times the length of said partially oriented monofilament (M 2 ); (C) passing said monofilament (M 3 ) through a heating zone containing a gas at about 200°-800° C. that is inert to said monofilament to (M 3 ) for about 0.05-5 seconds and drawing said relaxed monofilament (M 3 ) to about 1.2-2.5 times the length of said relaxed monofilament (M 3 ) to produce a drawn monofilament (M 4 ); and (D) passing said drawn monofilament (M 4 ) through a hot water zone containing hot water at about 50°-97° C. for about 0.05-20 seconds and relaxing said monofilament (M 4 ) to about 0.9-1.0 times the length of said drawn monofilament (M 4 ) to produce a heatset monofilament (M 5 ).

Claim 16

A process for producing polyamide monofilament having a cross-sectional structure comprising a two-layer structure consisting of a core and a skin layer, an average index of birefringence of at least about 50×10 -3 and a degree of molecular orientation in the amorphous region of said skin layer of not more than about 0.5, which process comprises the steps of: (A) drawing melt spun undrawn polyamide monofilament (M 1 ) at a ratio of about 3-5.5 to produce a partially oriented monofilament (M 2 ) having a diameter of about 0.05-2 mm; (B) passing said monofilament (M 2 ) through a pressure chamber filled with saturated steam having a pressure not less than about 1 kg/cm 2 ·G for about 0.05-5 seconds to prepare a relaxed monofilament (M 3 ) relaxed to 0.7-1.0 times the length of said partially oriented monofilament (M 2 ); (C) passing said monofilament (M 3 ) through a heating zone containing a gas at about 200°-800° C. that is inert to said monofilament to (M 3 ) for about 0.05-5 seconds and drawing said relaxed monofilament (M 3 ) to about 1.2-2.5 times the length of said relaxed monofilament (M 3 ) to produce a drawn monofilament (M 4 ); and (D) passing said drawn monofilament (M 4 ) through a hot water zone containing hot water at about 50°-97° C. for about 0.05-20 seconds and relaxing said monofilament (M 4 ) to about 0.9-1.0 times the length of said drawn monofilament (M 4 ) to produce a heatset monofilament (M 5 ).

Claim 17

A process for producing polyamide monofilament having a cross-sectional structure comprising a two-layer structure consisting of a core and a skin layer, an average index of birefringence of at least about 50×10 -3 and a degree of molecular orientation in the amorphous region of said skin layer of not more than about 0.5, which process comprises the steps of: (A) drawing melt spun undrawn polyamide monofilament (M 1 ) at a ratio of about 3-5.5 to produce a partially oriented monofilament (M 2 ) having a diameter of about 0.05-2 mm; (B) passing said monofilament (M 2 ) through a pressure chamber filled with saturated steam having a pressure not less than about 1 kg/cm 2 ·G for about 0.05-5 seconds to prepare a relaxed monofilament (M 3 ) relaxed to 0.7-1.0 times the length of said partially oriented monofilament (M 2 ); (C) passing said monofilament (M 3 ) through a heating zone containing a liquid at about 150°-265° C. that is inert to said monofilament (M 3 ) for about 0.05-5 seconds and drawing said relaxed monofilament (M 3 ) to about 1.2-2.5 times the length of said relaxed monofilament (M 3 ) to produce a drawn monofilament (M 4 ); and (D) passing said drawn monofilament (M 4 ) through a hot water zone containing hot water at about 50°-97° C. for about 0.05-20 seconds and relaxing said monofilament (M 4 ) to about 0.9-1.0 times the length of said drawn monofilament (M 4 ) to produce a heatset monofilament (M 5 ).

Claim 18

A process for producing polyamide monofilament having a cross-sectional structure comprising a two-layer structure consisting of a core and a skin layer, an average index of birefringence of at least about 50×10 -3 and a degree of molecular orientation in the amorphous region of said skin layer of not more than about 0.5, which process comprises the steps of: (A) drawing melt spun undrawn polyamide monofilament (M 1 ) at a ratio of about 3-5.5 to produce a partially oriented monofilament (M 2 ) having a diameter of about 0.05-2 mm; (B) passing said monofilament (M 2 ) through a pressure chamber filled with saturated steam having a pressure not less than about 1 kg/cm 2 ·G for about 0.05-5 seconds to prepare a relaxed monofilament (M 3 ) relaxed to 0.7-1.0 times the length of said partially oriented monofilament (M 2 ); (C) passing said monofilament (M 3 ) through a heating zone containing a liquid at about 150°-265° C. that is inert to said monofilament (M 3 ) for about 0.05-5 seconds and drawing said relaxed monofilament (M 3 ) to about 1.2-2.5 times the length of said relaxed monofilament (M 3 ) to produce a drawn monofilament (M 4 ); and (D) passing said drawn monofilament (M 4 ) through a hot water zone containing hot water at about 50°-97° C. for about 0.05-20 seconds and relaxing said monofilament (M 4 ) to about 0.9-1.0 times the length of said drawn monofilament (M 4 ) to produce a heatset monofilament (M 5 ).

Claim 19

A process for producing polyamide monofilament having a cross-sectional structure comprising a two-layer structure consisting of a core and a skin layer, an average index of birefringence of at least about 50×10 -3 and a degree of molecular orientation in the amorphous region of said skin layer of not more than about 0.5, which process comprises the steps of: (A) drawing melt spun undrawn polyamide monofilament (M 1 ) at a ratio of about 3-5.5 to produce a partially oriented monofilament (M 2 ) having a diameter of about 0.05-2 mm; (B) passing said monofilament (M 2 ) through a pressure chamber filled with saturated steam having a pressure not less than about 1 kg/cm 2 ·G for about 0.05-5 seconds to produce a relaxed monofilament (M 3 ) relaxed to 0.7-1.0 times the length of said partially oriented monofilament (M 2 ); (C) passing said monofilament (M 3 ) through a heating zone containing a gas at about 200°-800° C. for about 0.05-5 seconds simultaneously with drawing said relaxed monofilament (M 3 ) to about 1.2-2.5 times the length of said relaxed monofilament (M 3 ) to produce a drawn monofilament (M 4 ), said gas being inert to said monofilament (M 3 ), and (D) passing said drawn monofilament (M 4 ) through a hot water zone containing hot water at about 50°-97° C. for about 0.05-20 seconds and relaxing said monofilament (M 4 ) to about 0.9-1.0 times the length of said drawn monofilament (M 4 ) to produce a heatset monofilament (M 5 ).

Claim 20

A process for producing polyamide monofilament having a cross-sectional structure comprising a two-layer structure consisting of a core and a skin layer, an average index of birefringence of at least about 50×10 -3 and a degree of molecular orientation in the amorphous region of said skin layer of not more than about 0.5, which process comprises the steps of: (A) drawing melt spun undrawn polyamide monofilament (M 1 ) at a ratio of about 3-5.5 to produce a partially oriented monofilament (M 2 ) having a diameter of about 0.05-2 mm; (B) passing said monofilament (M 2 ) through a pressure chamber filled with saturated steam having a pressure not less than about 1 kg/cm 2 ·G for about 0.05-5 seconds to produce a relaxed monofilament (M 3 ) relaxed to 0.7-1.0 times the length of said partially oriented monofilament (M 2 ); (C) passing said monofilament (M 3 ) through a heating zone containing a gas at about 200°-800° C. for about 0.05-5 seconds simultaneously with drawing said relaxed monofilament (M 3 ) to about 1.2-2.5 times the length of said relaxed monofilament (M 3 ) to produce a drawn monofilament (M 4 ), said gas being inert to said monofilament (M 3 ), and (D) passing said drawn monofilament (M 4 ) through a hot water zone containing hot water at about 50°-97° C. for about 0.05-20 seconds and relaxing said monofilament (M 4 ) to about 0.9-1.0 times the length of said drawn monofilament (M 4 ) to produce a heatset monofilament (M 5 ).

Claim 21

A process according to claim 7, 10, 11 or 12 wherein said polyamide is a polycapramide homopolymer.

Claim 22

A process according to claim 7, 10, 11 or 12 wherein said polyamide is copolyamide, at least 85% of the total weight thereof is occupied by a polycapramide component.

Claim 23

A process according to claim 7, 10, 11 or 12 wherein said polyamide is blended polyamide, and wherein at least about 85% of the total weight thereof is occupied by polycapramide.

Claim 24

A process according to claim 7, 10, 11 or 12 wherein said inert gas is air.

Claim 25

A process according to claim 7, 10, 11 or 12 wherein said inert liquid is a member selected from the group consisting of glycerin, ethylene glycol, polyethylene glycol, polyorganosiloxane oil, mineral oil and vegetable oil.