CA1047723A - Polypropylene fibres and process for the manufacture thereof - Google Patents
Polypropylene fibres and process for the manufacture thereofInfo
- Publication number
- CA1047723A CA1047723A CA212,682A CA212682A CA1047723A CA 1047723 A CA1047723 A CA 1047723A CA 212682 A CA212682 A CA 212682A CA 1047723 A CA1047723 A CA 1047723A
- Authority
- CA
- Canada
- Prior art keywords
- film
- fibre
- polybutadiene
- blend
- polypropylene
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- D—TEXTILES; PAPER
- D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
- D01D—MECHANICAL METHODS OR APPARATUS IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS
- D01D5/00—Formation of filaments, threads, or the like
- D01D5/42—Formation of filaments, threads, or the like by cutting films into narrow ribbons or filaments or by fibrillation of films or filaments
- D01D5/423—Formation of filaments, threads, or the like by cutting films into narrow ribbons or filaments or by fibrillation of films or filaments by fibrillation of films or filaments
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Textile Engineering (AREA)
- Artificial Filaments (AREA)
- Compositions Of Macromolecular Compounds (AREA)
Abstract
A B S T R A C T
A synthetic fibre having a denier of 1000 or lower and consisting of a blend of 70-99.5%w of polypropylene and 30-0.5%w of polybutadiene.
Articles comprising said fibres, and process for the manufacture of said fibres by film splitting.
A synthetic fibre having a denier of 1000 or lower and consisting of a blend of 70-99.5%w of polypropylene and 30-0.5%w of polybutadiene.
Articles comprising said fibres, and process for the manufacture of said fibres by film splitting.
Description
~()477Z3 The invention relates to a novel synthetic fibre of a low denier range and containing polypropylene admixed with polybutadiene. The invention also relates to a process for the manufacture of such fibres.
It is known to manufacture fibres of polymeric ma-terial by spinning, i.e., by extruding of a molten polymer through a spinneret. It is also known to manufacture such fibres by film splitting. In the latter method the molten polymer is extruded through a linear or annular slit to form a film, which film may, for instance, be stretched to effect molecular orientation and subsequently subjected to a mechanical treatment to induce splitting of the stretched film.
The use of polypropylene as starting material in the methods as mentioned above is well-known. Although it offers important advantages over other-fibre-forming polymers, commer-cial acceptance in the field of fibre manufacture, particularly in the low denier range, has in some cases been hampered by some properties which to a certain extent seemed inherent to fibres of polypropylene, such as a hard hand and a gloss which gives --them a "synthetic" appearance.
Blending polyolefinic starting material with synthetic rubbers to improve properties other than those mentioned above of fibres made from the polyolefinic material, such as tensile strength and crimp stability, has been suggested previously for high denier filaments. One could, therefore, expect that the addition of a synthetic rubber might also give improvement with respect to fibre appearance but it has been found that , . : - : . . , . . : - . :
iO477Z3 most elastomers do not or only to a very limited extent fulfil this expectation.
In contrast with these generally disappointing results it has surprisingly been found that the aforementioned disadvantages of polypropylene-derived fibres of low denier are avoided or at least considerably reduced by starting from polypropylene contain-ing a certain amount of polybutadiene, yielding fibres with not only a mat surface but also a remarkably soft hand resembling that of silk. Moreover, fibres of such a blend with polybutadiene exhibit other attractive properties such as improved resilience and better dyeability, without appreciable loss in tenacity.
Accordingly, the invention provides a synthetic fibre ;
having a denier of 1,000 or lower and consisting of a blend of 70-99.5%w of polypropylene and 30-0.5%w of polybutadiene.
The indication "%w" as used in this specification in-variably means percentage by weight with respect to the total com-position concerned. The term "polypropylene" is meant to indicate any plastic product obtained by the polymerization of propylene, irrespective of the polymerization method used, its molecular weight or its configuration. It will be appreciated that commer- -cial grades of polypropylene may contain small amounts of mono-mers other than propylene, in the polymerized form. Such grades -are included but the term "polypropylene" as used hereinafter excludes, for instance, propylene random or block copolymers with - -an ethylene content of 10%w or more. A simular qualification -applies to the term "polybutadiene", which term excludes, for -- -~47723 instance, butadiene block copolymers and butadiene random copolymers containing 10%w or more of other monomer(s) in polymerized form.
Preferably, the polybutadiene contained in the fibre according to the invention is a stereospecific polybutadiene with a high cis 1,4-content, for instance, 90% or higher. As to the molecular weight of the polybutadiene to be employed, preferred average molecular weights are between 100,000 and 500,000.
The polybutadiene content of the fibre according to the invention is preferably 2-20%w, a range of 5-10%w being most preferred.
Other components may also be present, such as anti-oxidants, stabilizers, plasticizers, flow improvers, lubricants, pigments, and dyeability im-provers. The use of fillers, such as talc, chalk, metal salts of higher fatty acids, and asbestos, is particularly suitable in some cases. The starting material may additionally contain polymeric compounds other than polypropylene and polybutadiene. Preferred components of the latter type comprise, for instance, homo- or copolymers of ethylene in amounts of 1-20%w.
A particularly preferred additional component is high-density polyethylene ~ -in an amount of 5-15%w.
The invention also extends to articles comprising the ~-novel fibres as hereinbefore described. Such articles include yarns and other textile materials, such as woven, knitted, and non-woven fabrics, as well as ropes, cordà ge, upholstery and floor-covering structures, and also encompass materials beyond the textile field, e.g. cellulosic or synthetic paper and concrete structures.
.
~)477Z3 As indicated above, the invention also relates to a process for the manufacture of the novel fibres as hereinbefore described, in which a stretched film of a blend containing 70-99.5%w of polypropylene and 30-0.5%w of polybutadiene is subjected to a mechanical treatment to induce splitting of the stretched film.
In such a process the advantages of the polybutadiene component with respect to fibre appearance as explained hereinbefore are of particular importance in view of the fundamentally non-round cross-section of the fibres obtained in such a process. Moreover, when comparing fibres obtained by such a process under the same pro~
cess conditions starting from a film of polypropylene without --polybutadiene and one of polypropylene blended with polybutadiene, the polybutadiene-containing fibres have not only a considerably lower average denier but also a narrower denier range, which ~ -~
latter property is of particular advantage in many textile opera-tions.
The mechanical treatment of the stretched film as employed in the present process comprises all known film-splitting methods, such as grating, twisting, brushing, cutting, rubbing, ~ -exposure to a gas jet or a rapid stream of solid particles, or, under certain conditions, merely winding up under tension. A
method preferably employed in the present process is in many cases to pass a stretched film under tension over a rotating cylinder provided with pins on its surface, the latter moving, at the area of contact, in the same direction as but more ra-pidly than the film. Particularly preferred is the use of a .:
.... . . , ~ . : :
1~47723 cylinder provided with pins positioned in rows substantially parallel to the cylinder axis. ~nder suitable conditions such embodiment of the present process yields a more or less regular or a completely irregular network of fibres within the required denier range of 1000 or less as indicated here-inbefore.
The process of the invention may be carried out in many - -other ways. In a preferred embodiment thereof the film to be converted into fibres is a profiled film having on at least one surface thereof parallel ridges in longitudinal direction, which film may suitably be made by ex-trusion of the blend through a slit having projections. Such ridges pre-determine to a certain extent the degree of splitting when the film is sub-jected to a mechanical treatment. In another preferred embodiment the pro-filed film is made by subjecting a web of the blend to an embossing treat ment, at a temperature which may be below the crystalline melting point of the polymeric starting material or above that melting point, the embossing treatment being followed by stretching the embossed web. If necessary, the so obtained film in stretched condition may be subjected to one of the above-mentioned mechanical treatments to obtain a fibrous product but in many cases winding up under tension is sufficient to give satisfactory splitting. In this embodiment the embossing is generally effected by pass-ing the web under pressure contact through the nip formed between two 1~)47723 contra-rotating rollers or belts having non-yielding surfaces, at least one of the roller or belts being profiled.
EXAMPLE
A masterbatch was made by mixing 40 parts by weight ~pbw) of a stereo-specific high cis-1,4-polybutadiene having an average molecular weight of 300,000 determined by gel permeation chromatography, and 60 pbw of a polypropylene having a melt index of 1.5 g/10 min. determined according to ASTM/D 1238-70, condition E.
The masterbatch was reduced to four blends containing -1, 5, 10 and 20%w of rubber, respectively, by mixing with the required additional amount of the above-mentioned polypropylene in a tumbler for 15 minutes. From each of these blends, and from the above-mentioned polypropylene without rubber, a film of - -a width of 250 mm was made by extrusion at 250C through a linear slit of 0.5 mm height.
Each of the films was stretched at 145C at a stretch-ing ratio of 1:8, followed by relaxation without stress at 65C, and split by passing it over a pinned roler using a contact length between roller and film of 15 cm.
Comparing the fibres so obtained with increasing poly-butadiene content they appeared to have an increasingly soft -and silky hand. Other properties are given in the following `--Table:
. -.
.
1~47723 Polybutadiene Average Tenacity content, denier %w ~gl9000 m) (g/denier) 0 14 2.41 1 12 2.30
It is known to manufacture fibres of polymeric ma-terial by spinning, i.e., by extruding of a molten polymer through a spinneret. It is also known to manufacture such fibres by film splitting. In the latter method the molten polymer is extruded through a linear or annular slit to form a film, which film may, for instance, be stretched to effect molecular orientation and subsequently subjected to a mechanical treatment to induce splitting of the stretched film.
The use of polypropylene as starting material in the methods as mentioned above is well-known. Although it offers important advantages over other-fibre-forming polymers, commer-cial acceptance in the field of fibre manufacture, particularly in the low denier range, has in some cases been hampered by some properties which to a certain extent seemed inherent to fibres of polypropylene, such as a hard hand and a gloss which gives --them a "synthetic" appearance.
Blending polyolefinic starting material with synthetic rubbers to improve properties other than those mentioned above of fibres made from the polyolefinic material, such as tensile strength and crimp stability, has been suggested previously for high denier filaments. One could, therefore, expect that the addition of a synthetic rubber might also give improvement with respect to fibre appearance but it has been found that , . : - : . . , . . : - . :
iO477Z3 most elastomers do not or only to a very limited extent fulfil this expectation.
In contrast with these generally disappointing results it has surprisingly been found that the aforementioned disadvantages of polypropylene-derived fibres of low denier are avoided or at least considerably reduced by starting from polypropylene contain-ing a certain amount of polybutadiene, yielding fibres with not only a mat surface but also a remarkably soft hand resembling that of silk. Moreover, fibres of such a blend with polybutadiene exhibit other attractive properties such as improved resilience and better dyeability, without appreciable loss in tenacity.
Accordingly, the invention provides a synthetic fibre ;
having a denier of 1,000 or lower and consisting of a blend of 70-99.5%w of polypropylene and 30-0.5%w of polybutadiene.
The indication "%w" as used in this specification in-variably means percentage by weight with respect to the total com-position concerned. The term "polypropylene" is meant to indicate any plastic product obtained by the polymerization of propylene, irrespective of the polymerization method used, its molecular weight or its configuration. It will be appreciated that commer- -cial grades of polypropylene may contain small amounts of mono-mers other than propylene, in the polymerized form. Such grades -are included but the term "polypropylene" as used hereinafter excludes, for instance, propylene random or block copolymers with - -an ethylene content of 10%w or more. A simular qualification -applies to the term "polybutadiene", which term excludes, for -- -~47723 instance, butadiene block copolymers and butadiene random copolymers containing 10%w or more of other monomer(s) in polymerized form.
Preferably, the polybutadiene contained in the fibre according to the invention is a stereospecific polybutadiene with a high cis 1,4-content, for instance, 90% or higher. As to the molecular weight of the polybutadiene to be employed, preferred average molecular weights are between 100,000 and 500,000.
The polybutadiene content of the fibre according to the invention is preferably 2-20%w, a range of 5-10%w being most preferred.
Other components may also be present, such as anti-oxidants, stabilizers, plasticizers, flow improvers, lubricants, pigments, and dyeability im-provers. The use of fillers, such as talc, chalk, metal salts of higher fatty acids, and asbestos, is particularly suitable in some cases. The starting material may additionally contain polymeric compounds other than polypropylene and polybutadiene. Preferred components of the latter type comprise, for instance, homo- or copolymers of ethylene in amounts of 1-20%w.
A particularly preferred additional component is high-density polyethylene ~ -in an amount of 5-15%w.
The invention also extends to articles comprising the ~-novel fibres as hereinbefore described. Such articles include yarns and other textile materials, such as woven, knitted, and non-woven fabrics, as well as ropes, cordà ge, upholstery and floor-covering structures, and also encompass materials beyond the textile field, e.g. cellulosic or synthetic paper and concrete structures.
.
~)477Z3 As indicated above, the invention also relates to a process for the manufacture of the novel fibres as hereinbefore described, in which a stretched film of a blend containing 70-99.5%w of polypropylene and 30-0.5%w of polybutadiene is subjected to a mechanical treatment to induce splitting of the stretched film.
In such a process the advantages of the polybutadiene component with respect to fibre appearance as explained hereinbefore are of particular importance in view of the fundamentally non-round cross-section of the fibres obtained in such a process. Moreover, when comparing fibres obtained by such a process under the same pro~
cess conditions starting from a film of polypropylene without --polybutadiene and one of polypropylene blended with polybutadiene, the polybutadiene-containing fibres have not only a considerably lower average denier but also a narrower denier range, which ~ -~
latter property is of particular advantage in many textile opera-tions.
The mechanical treatment of the stretched film as employed in the present process comprises all known film-splitting methods, such as grating, twisting, brushing, cutting, rubbing, ~ -exposure to a gas jet or a rapid stream of solid particles, or, under certain conditions, merely winding up under tension. A
method preferably employed in the present process is in many cases to pass a stretched film under tension over a rotating cylinder provided with pins on its surface, the latter moving, at the area of contact, in the same direction as but more ra-pidly than the film. Particularly preferred is the use of a .:
.... . . , ~ . : :
1~47723 cylinder provided with pins positioned in rows substantially parallel to the cylinder axis. ~nder suitable conditions such embodiment of the present process yields a more or less regular or a completely irregular network of fibres within the required denier range of 1000 or less as indicated here-inbefore.
The process of the invention may be carried out in many - -other ways. In a preferred embodiment thereof the film to be converted into fibres is a profiled film having on at least one surface thereof parallel ridges in longitudinal direction, which film may suitably be made by ex-trusion of the blend through a slit having projections. Such ridges pre-determine to a certain extent the degree of splitting when the film is sub-jected to a mechanical treatment. In another preferred embodiment the pro-filed film is made by subjecting a web of the blend to an embossing treat ment, at a temperature which may be below the crystalline melting point of the polymeric starting material or above that melting point, the embossing treatment being followed by stretching the embossed web. If necessary, the so obtained film in stretched condition may be subjected to one of the above-mentioned mechanical treatments to obtain a fibrous product but in many cases winding up under tension is sufficient to give satisfactory splitting. In this embodiment the embossing is generally effected by pass-ing the web under pressure contact through the nip formed between two 1~)47723 contra-rotating rollers or belts having non-yielding surfaces, at least one of the roller or belts being profiled.
EXAMPLE
A masterbatch was made by mixing 40 parts by weight ~pbw) of a stereo-specific high cis-1,4-polybutadiene having an average molecular weight of 300,000 determined by gel permeation chromatography, and 60 pbw of a polypropylene having a melt index of 1.5 g/10 min. determined according to ASTM/D 1238-70, condition E.
The masterbatch was reduced to four blends containing -1, 5, 10 and 20%w of rubber, respectively, by mixing with the required additional amount of the above-mentioned polypropylene in a tumbler for 15 minutes. From each of these blends, and from the above-mentioned polypropylene without rubber, a film of - -a width of 250 mm was made by extrusion at 250C through a linear slit of 0.5 mm height.
Each of the films was stretched at 145C at a stretch-ing ratio of 1:8, followed by relaxation without stress at 65C, and split by passing it over a pinned roler using a contact length between roller and film of 15 cm.
Comparing the fibres so obtained with increasing poly-butadiene content they appeared to have an increasingly soft -and silky hand. Other properties are given in the following `--Table:
. -.
.
1~47723 Polybutadiene Average Tenacity content, denier %w ~gl9000 m) (g/denier) 0 14 2.41 1 12 2.30
2.23 - - -7 2.35 7 2.27 : ' Comparative experiments (l) A blend was made from 80%w of the above-mentioned polypropylene and 20%w of a styrene-polybutadiene rubber con-taining 23.5%w of bound styrene and having a Mooney viscosity of 52 at 100C. - -The blend was converted into film and the film sub-sequently stretched as described above. Splitting of the stretched film under the above-mentioned conditions resulted in fibres having an average of 10 denier but they appeared to have a very poor hand. ~
(2) A blend was made from 99%w of the above-mentioned -~ -polypropylene and l~ow of an isoprene rubber. Extrusion of this blend to produce a film appeared to be unsuccessful, as the isoprene rubber was incompatible with polypropylene under workable extrusion conditions for polypropylene.
(2) A blend was made from 99%w of the above-mentioned -~ -polypropylene and l~ow of an isoprene rubber. Extrusion of this blend to produce a film appeared to be unsuccessful, as the isoprene rubber was incompatible with polypropylene under workable extrusion conditions for polypropylene.
Claims (14)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A synthetic fibre having a denier of 1000 or lower and consisting of a blend of 70-99.5%w of polypropylene and 30-0.5%w of polybutadiene.
2. A fibre as claimed in claim 1, having a polybutadiene content of 2-20%w.
3. A fibre as claimed in claim 2, having a polybutadiene content of 5-10%w.
4. A fibre as claimed in any one of claims 1 to 3, having a denier of 100 or lower.
5. A fibre as claimed in any one of claims 1 to 3, having a denier within the range of 5-20.
6. A fibre as claimed in any one of claims 1 to 3, which contains 1-20%
w of a homo- or copolymer of ethylene as additional component.
w of a homo- or copolymer of ethylene as additional component.
7. A fiber as claimed in any one of claims 1 to 3, which contains 5-15%
w of a homo- or copolymer of ethylene as additional component.
w of a homo- or copolymer of ethylene as additional component.
8. Articles, including yarns, ropes, cordage, upholstery and floor cover-ing structures, comprising fibres as claimed in claim 1.
9. A process for the manufacture of a synthetic fibre having a denier of 1000 or lower and consisting of a blend of 70-99.5%w of polypropylene and 30-0.5%w of polybutadiene, in which process a stretched film of a blend con-taining 70-99.5%w of polypropylene and 30-0.5%w of polybutadiene is subjected to a mechanical treatment to induce splitting of the stretched film.
10. A process as claimed in claim 9, in which the stretched film is passed under tension over a rotating cylinder provided with pins on its sur-face, the latter moving, at the area of contact with the film, in the same direction as but more rapidly than the film.
11. A process as claimed in claim 10, in which the pins are positioned in rows substantially parallel to the cylinder axis.
12. A process as claimed in claim 9, in which the film is a profiled film having on at least one surface thereof parallel ridges in longitudinal direction.
13. A process as claimed in claim 12, in which the profiled film is made by extruding the blend in molten condition through a linear or annular slit having projections.
14. A process as claimed in claim 12, in which the profiled film is made by subjecting a web of the blend to an embossing treatment.
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB56577/73A GB1492738A (en) | 1973-12-06 | 1973-12-06 | Polypropylene fibres and process for the manufacture thereof |
Publications (1)
Publication Number | Publication Date |
---|---|
CA1047723A true CA1047723A (en) | 1979-02-06 |
Family
ID=10476978
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
CA212,682A Expired CA1047723A (en) | 1973-12-06 | 1974-10-30 | Polypropylene fibres and process for the manufacture thereof |
Country Status (8)
Country | Link |
---|---|
BE (1) | BE822935A (en) |
BR (1) | BR7410144A (en) |
CA (1) | CA1047723A (en) |
DE (1) | DE2457277A1 (en) |
FR (1) | FR2253850B1 (en) |
GB (1) | GB1492738A (en) |
IT (1) | IT1024971B (en) |
NO (1) | NO143070C (en) |
-
1973
- 1973-12-06 GB GB56577/73A patent/GB1492738A/en not_active Expired
-
1974
- 1974-10-30 CA CA212,682A patent/CA1047723A/en not_active Expired
- 1974-12-04 IT IT70520/74A patent/IT1024971B/en active
- 1974-12-04 BR BR10144/74A patent/BR7410144A/en unknown
- 1974-12-04 BE BE151145A patent/BE822935A/en unknown
- 1974-12-04 NO NO744373A patent/NO143070C/en unknown
- 1974-12-04 FR FR7439631A patent/FR2253850B1/fr not_active Expired
- 1974-12-04 DE DE19742457277 patent/DE2457277A1/en not_active Withdrawn
Also Published As
Publication number | Publication date |
---|---|
IT1024971B (en) | 1978-07-20 |
BE822935A (en) | 1975-06-04 |
BR7410144A (en) | 1976-06-08 |
NO744373L (en) | 1975-06-30 |
GB1492738A (en) | 1977-11-23 |
NO143070C (en) | 1980-12-10 |
NO143070B (en) | 1980-09-01 |
FR2253850A1 (en) | 1975-07-04 |
FR2253850B1 (en) | 1977-10-28 |
DE2457277A1 (en) | 1975-06-12 |
AU7607074A (en) | 1976-06-10 |
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