EP0260607A2 — Heat-adhesive composite fibers and method for mak…

Claim 1

Independent Claim 148 words

A heat-adhesive composite fiber comprising a core portion and a sheath portion, said core portion being of the side-by-side type composite structure comprising two core components of different polypropylene base polymers in a composite ratio of 1:2 to 2:1, one of said core components having a Q value, expressed in terms of the weight-average molecular weight/the number-average molecular weight, equal to or higher than 6 and the other having a Q value equal to lower than 5, and said sheath portion meeting at least the requirments that it should comprise a sheath component of a polyethylene base polymer having a melting point lower by at least 20°C than the lower one of the melting points of said two core components, and it should cover said core portion in a proportion of 25 to 55 % by weight based on the total weight of it and said core portion.

Claim 2

Dependent Claim 148 words

A heat-adhesive composite fiber comprising a core portion and a sheath portion, said core portion being of the side-by-side type composite structure comprising two core components of different polypropylene base polymers in a composite ratio of 1:2 to 2:1, one of said core components having a Q value, expressed in terms of the weight-average molecular weight/the number-average molecular weight, equal to or higher than 6 and the other having a Q value equal to lower than 5, and said sheath portion meeting at least the requirments that it should comprise a sheath component of a polyethylene base polymer having a melting point lower by at least 20°C than the lower one of the melting points of said two core components, and it should cover said core portion in a proportion of 25 to 55 % by weight based on the total weight of it and said core portion.

Claim 3

Dependent Claim 17 words

A heat-adhesive composite fiber as defined in Claim 1, wherein said sheath portion satisfies said requirements alone.

Claim 4

Dependent Claim 64 words

A heat-adhesive composite fiber as defined in Claim 1, wherein said sheath portion satisfies said requirements, and has a number of aggregatable portions, at least latently releasable, which form many modular aggregates thereon by a heat treatment at a temperature higher than the melting point of said sheath component but lower than the lower one of the melting points of said two core components.

Claim 5

Dependent Claim 30 words

A heat-adhesive composite fiber as defined in any one of Claims 1 to 3, wherein said polypropylene base polymer of at least one of said two core components is polypropylene.

Claim 6

Dependent Claim 43 words

A heat-adhesive composite fiber as defined in any one of Claims 1 to 3, wherein said polypropylene base polymer of at least one of said two core components is a copolymer of propylene with a small amount of an alpha-olefin except for propylene.

Claim 7

Dependent Claim 21 words

A heat-adhesive composite fiber as defined in any one of Claims 1 to 5, wherein said polyethylene base polymer is polyethylene.

Claim 8

Dependent Claim 35 words

A heat-adhesive composite fiber as defined in any one of Claims 1 to 5, wherein said polyethylene base polymer is an ethylene-vinyl acetate copolymer having an ethylene content of 98 to 60 % by weight.

Claim 9

Independent Claim 167 words

A method for making heat-adhesive composite fibers by separately subjecting to composite-spinning two polypropylene base polymers for two core components and a polyethylene base polymer for a sheath component, which has a melting point lower by at least 20°C than the lower one of the melting points of said two polypropylene base polymers, thereby obtaining a composite nonstretched yarn of the structure that a core portion of the side-by-side type composite structure consisting of two core components in a composite ratio of 1:2 to 2:1, one of said core components having a Q value, expressed in terms of the weight-average molecular weight/the number-average molecular weight, equal to or higher than 6 and the other having a Q value equal to or lower than 5, is covered with a sheath portion comprising said sheath component in a proportion of 25 to 55 % by weight based on the total weight of it and said core portion, and stretching said composite nonstretched yarn by one- or more-stage stretching process.

Claim 10

Independent Claim 167 words

A method for making heat-adhesive composite fibers by separately subjecting to composite-spinning two polypropylene base polymers for two core components and a polyethylene base polymer for a sheath component, which has a melting point lower by at least 20°C than the lower one of the melting points of said two polypropylene base polymers, thereby obtaining a composite nonstretched yarn of the structure that a core portion of the side-by-side type composite structure consisting of two core components in a composite ratio of 1:2 to 2:1, one of said core components having a Q value, expressed in terms of the weight-average molecular weight/the number-average molecular weight, equal to or higher than 6 and the other having a Q value equal to or lower than 5, is covered with a sheath portion comprising said sheath component in a proportion of 25 to 55 % by weight based on the total weight of it and said core portion, and stretching said composite nonstretched yarn by one- or more-stage stretching process.

Claim 11

Dependent Claim 33 words

A method as defined in Claim 8, wherein said composite unstretched yarn is stertched at a stretching temperature of normal temperature to 130°C inclusive and an overall draw ratio of 1.3 to 9.

Claim 12

Dependent Claim 116 words

A method as defined in Claim 8, wherein, prior to the stretching of said composite nonstretched yarn, said composite nonstretched yarn is heated under no tension at a temperature of 80°C to below the melting point of said sheath component for 10 seconds or longer and cooled down to normal temperature, and is then subjected to the first-stage stretching at normal temperature and a draw ratio of 1.3 to 2, and without letting the yarn loose it is subsequently subjected to the second-stage stretching at a temperature of 80°C to below the melting point of said sheath component and a draw ratio of at least 90 % of the maximum draw ratio of the second-stage stretching.

Claim 13

Dependent Claim 72 words

A method as defined in Claim 10, wherein, at the composite spinning step, at least one selected from polysiloxanes and fluorine compounds is added to at least one of said polypropylene base polymers for said core components and said polyethylene base polymer for said sheath component in an amount of 0.05 to 1.0 % by weight based on said polymer or polymers, followed by composite-spinning, and stretching the resulting composite nonstretched yarn.

Claim 14

Independent Claim 45 words

A method as defined in any one of Claims 8 to 11, wherein a polypropylene base polymer having a melt flow rate of 4 to 40 is used as said polypropylene base polymer for said core component having a Q value of 6 or more.

Claim 15

Independent Claim 45 words

A method as defined in any one of Claims 8 to 11, wherein a polypropylene base polymer having a melt flow rate of 4 to 60 is used as said polypropylene base polymer for said core component having a Q value of 5 or less.

Heat-adhesive composite fibers and method for making the same

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