CA2126013C - Spinning process for the preparation of high termoweldability polyolefin fibers - Google Patents
Spinning process for the preparation of high termoweldability polyolefin fibers Download PDFInfo
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- CA2126013C CA2126013C CA002126013A CA2126013A CA2126013C CA 2126013 C CA2126013 C CA 2126013C CA 002126013 A CA002126013 A CA 002126013A CA 2126013 A CA2126013 A CA 2126013A CA 2126013 C CA2126013 C CA 2126013C
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-
- 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
- D01D5/08—Melt spinning methods
-
- D—TEXTILES; PAPER
- D04—BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
- D04H—MAKING TEXTILE FABRICS, e.g. FROM FIBRES OR FILAMENTARY MATERIAL; FABRICS MADE BY SUCH PROCESSES OR APPARATUS, e.g. FELTS, NON-WOVEN FABRICS; COTTON-WOOL; WADDING ; NON-WOVEN FABRICS FROM STAPLE FIBRES, FILAMENTS OR YARNS, BONDED WITH AT LEAST ONE WEB-LIKE MATERIAL DURING THEIR CONSOLIDATION
- D04H1/00—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres
- D04H1/40—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties
- D04H1/54—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties by welding together the fibres, e.g. by partially melting or dissolving
- D04H1/542—Adhesive fibres
- D04H1/544—Olefin series
-
- D—TEXTILES; PAPER
- D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
- D01F—CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
- D01F6/00—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof
- D01F6/02—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from homopolymers obtained by reactions only involving carbon-to-carbon unsaturated bonds
- D01F6/04—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from homopolymers obtained by reactions only involving carbon-to-carbon unsaturated bonds from polyolefins
- D01F6/06—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from homopolymers obtained by reactions only involving carbon-to-carbon unsaturated bonds from polyolefins from polypropylene
-
- D—TEXTILES; PAPER
- D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
- D01F—CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
- D01F6/00—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof
- D01F6/28—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from copolymers obtained by reactions only involving carbon-to-carbon unsaturated bonds
- D01F6/30—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from copolymers obtained by reactions only involving carbon-to-carbon unsaturated bonds comprising olefins as the major constituent
-
- D—TEXTILES; PAPER
- D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
- D01F—CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
- D01F6/00—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof
- D01F6/44—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from mixtures of polymers obtained by reactions only involving carbon-to-carbon unsaturated bonds as major constituent with other polymers or low-molecular-weight compounds
- D01F6/46—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from mixtures of polymers obtained by reactions only involving carbon-to-carbon unsaturated bonds as major constituent with other polymers or low-molecular-weight compounds of polyolefins
-
- D—TEXTILES; PAPER
- D04—BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
- D04H—MAKING TEXTILE FABRICS, e.g. FROM FIBRES OR FILAMENTARY MATERIAL; FABRICS MADE BY SUCH PROCESSES OR APPARATUS, e.g. FELTS, NON-WOVEN FABRICS; COTTON-WOOL; WADDING ; NON-WOVEN FABRICS FROM STAPLE FIBRES, FILAMENTS OR YARNS, BONDED WITH AT LEAST ONE WEB-LIKE MATERIAL DURING THEIR CONSOLIDATION
- D04H1/00—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres
- D04H1/40—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties
- D04H1/54—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties by welding together the fibres, e.g. by partially melting or dissolving
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- Engineering & Computer Science (AREA)
- Textile Engineering (AREA)
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Mechanical Engineering (AREA)
- Artificial Filaments (AREA)
- Nonwoven Fabrics (AREA)
- Spinning Methods And Devices For Manufacturing Artificial Fibers (AREA)
- Multicomponent Fibers (AREA)
- Cell Separators (AREA)
Abstract
Disclosed are polyolefin fibers, for the preparation of nonwoven fabrics, prepared by using dies having a real or equivalent output diameter of the holes greater than or equal to 0.5 mm, with the proviso that for fibers having a count greater than or equal to 4 dtex, the ratio of the said output hole diameter to the count is greater than or equal to 0.06 mm/dtex.
Description
21 26p 13 Spinning Process For The Preparation Of High Thermoweldability Polyolefin Fibers The present invention relates to a spinning process for the preparation of thermowelda.ble polyolefin fibers, in particular polypropylene based fibers, suitable for the preparation of nonwoven fabrics.
Said nonwoven fabrics are particularly suitable for uses requiring considerable softness and tear resistance, 1o as is the case with coverstock for diapers and sanitary wear, which are made from low count fibers generally ranging from 0.2 to 5 dtex, or with other membranes made from fibers having a count between 3 and 10 dtex. The fundamental requirement of polyolefin fibers for nonwoven fabrics is that they must bond to each other by means of the joint action of temperature arid pressure on which the hot calendering processes are basE:d. This characteristic, called "thermoweldability", is not: always present in iB
polyolefin fibers, or at least not in the same degree. In fact thermoweldability basically depends on the type of polyolefin being span, the additives it contains, the type of process, and the spinning conditions used.
Published European Patent Application 391438 describes polyolefin compositions suitable for spinning and characterized by the presence of stabilizers selected from organic phosphites and/or phosphonites, HALS (Hindered Amine Light Stabilizers) and optionally phenolic to antioxidants.
The same patent application describes thermoweldable fibers obtained from the above mentioned stabilized polyolefin compositions by conventional spinning processes, in particular processes for the production of staple fibers. In this case the good levels of thermoweldability shown in the examples are due to the selection of the stabilizers. In the above mentioned examples fibers having a count ranging from 1.9 to 2.2 dtex are prepared by using n s 2126p13 a typical "long-spinning" apparatus (characterized, among other things, by high fiber-winding speed) equipped with a die having holes with 0.4 mm diameter.
Using a die whose holes have a small diameter (less than or equal to 0.4 mm) to produce low count fibers is typical of both the above mentioned long-spinning apparatus, as well as the "short-spinning" apparatus both used for producing staple fibers, and of the spun-bonding machines, because it enables high production levels to be to obtained.
In fact, the smaller the diameter of the holes, the higher the numbers of holes in the die, which means more fibers per unit of time. This is the reason why in the art the use of dies with diameters of the holes greater than 0.4 mm is limited to the productic>n of high-count fibers (higher than 5 dtex).
Now it has surprisingly been found that, both in the production of staple fibers and in the spun-bonding (B ' process, the use of dies with holes having diameters greater than or equal to 0.5 mm results in a marked increase of the thermoweldability of the fibers, provided that, for fibers having a count greater than 4 dtex, the ratio of hole diameter to the count is high enough.
Accordingly, the present invention provides a process for the preparation of thermoweldable fibers having a count ranging preferably from 0.2 to 10 dtex, more preferably from 0.5 to 3 dtex. The process comprises spinning an olefin polymer using a short-spinning or a spun-bonding apparatus including dies with holes. The holes of the dies have a real or equivalent output diameter of greater than or equal to 0.5 mm, particularly ranging from 0.5 to 2 mm.
Preferably, for fibers having a count greater than or equal to 4 dtex, the ratio of the said output hole diameter to the count is greater than or equal to 0.06 mm/dtex, more preferably greater than or equal t:o 0.08 mm/dtex, even more preferably greater than or equal i=o 0.1 mm/dtex.
As used herein, "output diameter of the holes" is the diameter of the holes at the outside surface of the die, i.e., on the front face of the die from which the fibers exit. Inside the thickness of the die, the diameter of the holes can be different from the diameter of the holes at the output. The "equivalent output diameter of the holes"
refers to instances where the hole is not round, in which case, for the purpose of the presE:nt invention, one considers the diameter of the ideal circle having an area 1o equal to the area of the output he>le, which corresponds to the above mentioned equivalent diameter.
The process of the present invention can be carried out by using both short-spinning apparatuses for the production of staple fibers, and :>pun-bonding apparatuses.
It has been found that thermoweldability of staple fibers improves as the fibers gathering speed decreases.
In particular, in the case of staple fibers, short-_ 21 260 13 spinning apparatuses are used; the apparatuses being characterized, among other things, by low fiber-gathering speeds (less than 500 m/min).
The above mentioned short-spinning apparatuses allow for a continuous operation, since the spinning speed is compatible with the drawing, crimping and cutting speeds, and due to their simplicity and reduced overall volume, these apparatuses are more economical than the long-spinning ones and suited for small scale productions.
1o However, up until now short-spinning apparatuses did not allow one to obtain staple fibers having good thermoweldability values (higher than 2.5 N, for example, according to the measuring method described in the examples). The process of the present invention, therefore, assumes particular importance when short-spinning apparatuses are used, because it solves the problem of producing thermoweldable staple fibers even when operating with said apparatuses.
s The process conditions which are best suited to be used according to the present invention using short-spinning apparatuses are the following.
The hole flow rate ranges from 0.005 to 0.18 g/min, preferably from 0.008 to 0.070 g/min, more preferably from 0.010 to 0.030 g/min. The fiber gathering speed ranges from 30 to 500 m/min, preferably :From 40 to 250 m/min, more preferably from 50 to 100 m/min. The draw ratios range from 1.10 to 3.50, preferably from 1.20 to 2.50. Moreover, 1o the fiber cooling and solidification space at the output of the die (cooling space) is preferably greater than 2 mm, more preferably greater than 10 mm, in particular from 10 to 350 mm.
The cooling is generally induced by an air jet or flow. Therefore, the cooling space is the distance between the die and the above mentioned air jet or flow.
Finally, according to the present invention it is preferable that the draw temperature be lower than 100°C, (B ' .. 21 260 13 in particular it should range from 15°C to 50°C. For further details on the short-spinning apparatuses reference is made to M. Ahmed, "Polypropylene fibers science and technology", Elsevier Scientific Publishing Company (1982) pages 344-346.
The spinning temperature for the above short-spinning apparatus generally ranges from 29:0°C to 310°C, preferably from 270°C to 300°C.
The equipment used in the process of spun-bonding 1o normally includes an extruder with a die on its spinning head, a cooling tower, and an air suction gathering device that uses Venturi tubes.
Underneath this device, that uses air speed to control the fiber gathering speed, the filaments are usually gathered over a conveyor belt, where they are distributed forming a web for heat welding in a calender.
According to this invention, when using typical spun-bonding machinery, it is convenient to apply the process conditions that follows.
fB a ~i2~oi3 The hole flow rate ranges from 0.1 to 2.0 g/min;
preferably from 0.2 to 1.0 g/min.
The space where fibers cool and solidify after leaving the die (the cooling space) is preferably greater than 2 mm, more preferably greater than 10 mm and in particular in the range between 10 and 350 mm.
The fibers are generally cooled by means of an air jet or flow. The cooling space is the distance between the die and this air jet or flow.
The spinning temperature is generally between 230°C adn 300°C, preferably between 240°C and 280°C.
Generally, the olefin polymers that can be used in the process of the present invention for the production of thermoweldable fibers are polymers or copolymers, and their mixtures, of R-CH=CHZ olefins where R is a hydrogen atom or a C1-C6 alkyl radical. Particularly preferred are the following polymers:
1) isotactic or mainly isotactic propylene homopolymers;
Said nonwoven fabrics are particularly suitable for uses requiring considerable softness and tear resistance, 1o as is the case with coverstock for diapers and sanitary wear, which are made from low count fibers generally ranging from 0.2 to 5 dtex, or with other membranes made from fibers having a count between 3 and 10 dtex. The fundamental requirement of polyolefin fibers for nonwoven fabrics is that they must bond to each other by means of the joint action of temperature arid pressure on which the hot calendering processes are basE:d. This characteristic, called "thermoweldability", is not: always present in iB
polyolefin fibers, or at least not in the same degree. In fact thermoweldability basically depends on the type of polyolefin being span, the additives it contains, the type of process, and the spinning conditions used.
Published European Patent Application 391438 describes polyolefin compositions suitable for spinning and characterized by the presence of stabilizers selected from organic phosphites and/or phosphonites, HALS (Hindered Amine Light Stabilizers) and optionally phenolic to antioxidants.
The same patent application describes thermoweldable fibers obtained from the above mentioned stabilized polyolefin compositions by conventional spinning processes, in particular processes for the production of staple fibers. In this case the good levels of thermoweldability shown in the examples are due to the selection of the stabilizers. In the above mentioned examples fibers having a count ranging from 1.9 to 2.2 dtex are prepared by using n s 2126p13 a typical "long-spinning" apparatus (characterized, among other things, by high fiber-winding speed) equipped with a die having holes with 0.4 mm diameter.
Using a die whose holes have a small diameter (less than or equal to 0.4 mm) to produce low count fibers is typical of both the above mentioned long-spinning apparatus, as well as the "short-spinning" apparatus both used for producing staple fibers, and of the spun-bonding machines, because it enables high production levels to be to obtained.
In fact, the smaller the diameter of the holes, the higher the numbers of holes in the die, which means more fibers per unit of time. This is the reason why in the art the use of dies with diameters of the holes greater than 0.4 mm is limited to the productic>n of high-count fibers (higher than 5 dtex).
Now it has surprisingly been found that, both in the production of staple fibers and in the spun-bonding (B ' process, the use of dies with holes having diameters greater than or equal to 0.5 mm results in a marked increase of the thermoweldability of the fibers, provided that, for fibers having a count greater than 4 dtex, the ratio of hole diameter to the count is high enough.
Accordingly, the present invention provides a process for the preparation of thermoweldable fibers having a count ranging preferably from 0.2 to 10 dtex, more preferably from 0.5 to 3 dtex. The process comprises spinning an olefin polymer using a short-spinning or a spun-bonding apparatus including dies with holes. The holes of the dies have a real or equivalent output diameter of greater than or equal to 0.5 mm, particularly ranging from 0.5 to 2 mm.
Preferably, for fibers having a count greater than or equal to 4 dtex, the ratio of the said output hole diameter to the count is greater than or equal to 0.06 mm/dtex, more preferably greater than or equal t:o 0.08 mm/dtex, even more preferably greater than or equal i=o 0.1 mm/dtex.
As used herein, "output diameter of the holes" is the diameter of the holes at the outside surface of the die, i.e., on the front face of the die from which the fibers exit. Inside the thickness of the die, the diameter of the holes can be different from the diameter of the holes at the output. The "equivalent output diameter of the holes"
refers to instances where the hole is not round, in which case, for the purpose of the presE:nt invention, one considers the diameter of the ideal circle having an area 1o equal to the area of the output he>le, which corresponds to the above mentioned equivalent diameter.
The process of the present invention can be carried out by using both short-spinning apparatuses for the production of staple fibers, and :>pun-bonding apparatuses.
It has been found that thermoweldability of staple fibers improves as the fibers gathering speed decreases.
In particular, in the case of staple fibers, short-_ 21 260 13 spinning apparatuses are used; the apparatuses being characterized, among other things, by low fiber-gathering speeds (less than 500 m/min).
The above mentioned short-spinning apparatuses allow for a continuous operation, since the spinning speed is compatible with the drawing, crimping and cutting speeds, and due to their simplicity and reduced overall volume, these apparatuses are more economical than the long-spinning ones and suited for small scale productions.
1o However, up until now short-spinning apparatuses did not allow one to obtain staple fibers having good thermoweldability values (higher than 2.5 N, for example, according to the measuring method described in the examples). The process of the present invention, therefore, assumes particular importance when short-spinning apparatuses are used, because it solves the problem of producing thermoweldable staple fibers even when operating with said apparatuses.
s The process conditions which are best suited to be used according to the present invention using short-spinning apparatuses are the following.
The hole flow rate ranges from 0.005 to 0.18 g/min, preferably from 0.008 to 0.070 g/min, more preferably from 0.010 to 0.030 g/min. The fiber gathering speed ranges from 30 to 500 m/min, preferably :From 40 to 250 m/min, more preferably from 50 to 100 m/min. The draw ratios range from 1.10 to 3.50, preferably from 1.20 to 2.50. Moreover, 1o the fiber cooling and solidification space at the output of the die (cooling space) is preferably greater than 2 mm, more preferably greater than 10 mm, in particular from 10 to 350 mm.
The cooling is generally induced by an air jet or flow. Therefore, the cooling space is the distance between the die and the above mentioned air jet or flow.
Finally, according to the present invention it is preferable that the draw temperature be lower than 100°C, (B ' .. 21 260 13 in particular it should range from 15°C to 50°C. For further details on the short-spinning apparatuses reference is made to M. Ahmed, "Polypropylene fibers science and technology", Elsevier Scientific Publishing Company (1982) pages 344-346.
The spinning temperature for the above short-spinning apparatus generally ranges from 29:0°C to 310°C, preferably from 270°C to 300°C.
The equipment used in the process of spun-bonding 1o normally includes an extruder with a die on its spinning head, a cooling tower, and an air suction gathering device that uses Venturi tubes.
Underneath this device, that uses air speed to control the fiber gathering speed, the filaments are usually gathered over a conveyor belt, where they are distributed forming a web for heat welding in a calender.
According to this invention, when using typical spun-bonding machinery, it is convenient to apply the process conditions that follows.
fB a ~i2~oi3 The hole flow rate ranges from 0.1 to 2.0 g/min;
preferably from 0.2 to 1.0 g/min.
The space where fibers cool and solidify after leaving the die (the cooling space) is preferably greater than 2 mm, more preferably greater than 10 mm and in particular in the range between 10 and 350 mm.
The fibers are generally cooled by means of an air jet or flow. The cooling space is the distance between the die and this air jet or flow.
The spinning temperature is generally between 230°C adn 300°C, preferably between 240°C and 280°C.
Generally, the olefin polymers that can be used in the process of the present invention for the production of thermoweldable fibers are polymers or copolymers, and their mixtures, of R-CH=CHZ olefins where R is a hydrogen atom or a C1-C6 alkyl radical. Particularly preferred are the following polymers:
1) isotactic or mainly isotactic propylene homopolymers;
2) crystalline copolymers of propylene with ethylene and/or C4-CB alpha-olefins, such as for example 1-butene, 1-hexene, 1-octene, 4-methyl-1-pentene, wherein the total comonomer content ranges from 0.050 to 20o by weight, or mixtures of said copolymers with isotactic or mainly isotactic propylene homopolym~=rs ;
3) heterophasic copolymers comprising (A) a propylene (HM 5198 + HM 5238 EST) - 9 -212fi013 homopolymer and/or one of the copolymers of item 2), and an elastomeric fraction (B) comprising copolymers of ethylene with propylene and/or a C4-Cg alpha-olefin, optionally containing minor cluantities of a dime, such as butadiene, 1,4-hexadiene, 1,5-hexadiene, ethylidene-1-norbornene.
Preferably the amount of dime in (B) is from 1% to 10%
by weight.
The heterophasic copolymers (a) are prepared according to known methods by mixing the components in the molten state, or by sequential copolymerization, and generally contain the copolymer fraction (B) in quantities ranging from 5% to 80% by weight.
Specific examples of olefin polymers particularly suitable for the preparation of thermoweldable fibers are the following propylene random copolymers:
a) crystalline propylene random copolymers containing from 1 . 5 % to 20 % by weight of ethy:Lene or C4-Ca alpha-olefins;
b) crystalline propylene random copolymers containing from 85 % to 96 % by weight of propylene, from 1 . 5 % to 5% by weight of ethylene, and from 2.5% to 10% by weight of a C4-C8 alpha- olefin;
c) crystalline propylene random copolymers compositions comprising (percentages by weight):
(1) from 30% to 65% of a copolymer of propylene with a (HM 5198 + HM 5238 EST) - 10 -~_ zzzsa~3 C4-C8 alpha-olefin, containing from 80% to 98% of propylene; and (2) from 35% to 70% of a propylene copolymer with ethylene, and optionally with a C4-Cg alpha-olefin in quantity ranging from 2% to 10%; said copolymer containing from 2 % to 10%' of ethylene when the above mentioned C4-CB alpha-olei_in is not present, and from 0 . 5 % to 5 % of ethylene when the C4-Cg alpha-olef in is present;
d) compositions of crystalline propylene random copolymers and crystalline ethylene copolymers comprising (percentages by weight) (1) from 40% to 70% of one or more crystalline propylene copolymers with one or more comonomers selected from ethylene and/or C4-CA alpha-olefin, wherein the comonomer or comonomers content is from 5% to 20%;
(2) from 30% to 60% of LLDPE having a MFR E (according to ASTM D 1238) from 0.1 to 15.
The above mentioned copolymers can also be used mixed with each other and/or with isotactic or mainly isotactic propylene homopolymers.
Other specific examples of olefin polymers particularly suitable for the preparation of thermoweldable fibers are heterophasic copolymers comprising from 5% to 95 % by weight of an isotactic or mainly isotactic propylene homopolymer, and/or (HM 5198 + HM 5238 EST) - 11 -a random propylene copolymer of the above mentioned types from a) to d), and from 95% to 5% by weight of a composition selected from:
(I) a composition comprising:
(i) 10-60 parts by weight of propylene homopolymer with an isotactic index higher than 90, or of a crystalline copolymer of propylene with ethylene and/or another C4-C8 alpha-olefin, containing over 85% by weight of propylene, and having an isotactic index higher than 85;
(ii) 10-40 parts by weight of a crystalline polymer fraction containing ethylene, insoluble in xylene at ambient temperature;
(iii) 30-60 parts by weight of an amorphous ethylene-propylene copolymer fraction optionally containing minor portions of a diene, soluble in xylene at ambient temperature and containing from 40 to 70% by weight of ethylene;
(II) a composition comprising:
(i) 10-50 parts by weight of propylene homopolymer with an isotactic index higher than 80, or a copolymer of propylene with ethylene and/or a C4-CB alpha-olefin containing over 85% by weight of propylene;
(ii) 5-20 parts by weight of a copolymer fraction containing ethylene, insoluble in xylene at ambient (HM 5198 + HM 5238 EST) - 12 -212601.3 temperature;
(iii) 40-80 parts by weight ~of a copolymer fraction of ethylene with propylene and/or a C4-CB alpha-olefin, and optionally with minor portions of dime, containing less than 40s by weight of ethylene, said fraction being soluble in xylene at ambient temperature, and havin~3 an intrinsic viscosity ranging from 1.5 to 4 dl/g.
Specific examples of C4-CB alpha olefins and dienes have been given above.
Generally, when used in the production of staple fibers the above mentioned olefin polymers have a Melt Flow Rate (MFR), determined according to ASTNID 1238-L, ranging from 0.5 to 100 g/10 min., preferably from 1.5 to 35 g/10 min..
When used in the spun-bonding apparatuses with the process of the present invention, the above. mentioned olefin polymers have preferably a MFR value between 5 and 25 g/10 min., in particular from 8 to 15 g/10 min.. These values of MFR
constitute an additional distinctive feature of the process of the invention, because in conventional spun-bonding processes polyolefins have a MFR greater than 25 g/10 min.
The above said values of MFR. are obtained directly in polymerization, or by controlled degradation. In order to obtain said controlled degradation c:~e adds, for example, organic peroxides in the spinning line or in the preceding (HM 5198 + HM 5238 EST) - 13 -. _. _ __.__ ...~_5.*~:,.__ __....,".....~.. _ __ . _. . _ , _ ...:
steps of pelletization of the olefin polymers. Olefin polymers are generally used in the form of pellets or nonextruded particles, such as flakes or spheres, for example.
Preferably the olefin polymers which are subjected to spinning with either process of the present invention are stabilized with the types and ~xuantities of stabilizers described in published European patent application 391438.
According to said patent application the polyolefins to be used for spinning contain one or more of the following stabilizers a) from 0.01 to 0.5o by weight: of one or more organic phosphites and/or phosphonites;
b) from 0.005 to 0.5% by weight of one or more HALS
(Hindered Amine Light Stabilizer);
and optionally one or more phenolic antioxidants in concentration which does not exceed 0.02% by weight.
The above stabilizers car. be added to the polyolefins by means of pelletization or surface coating, or they can be mechanically mixed with the polyole~fins.
Specific examples of phosphite~s are:
tris(2,4-di-tert-butylphenyl)phosph.ite marketed by CIBA GEIGY
under the trademark Irgafos 168; distearyl pentaerythritol diphosphite marketed by BORG-WA~tNER CHEMICAL under the trademark Weston 618; 4,4'-buty:Lidenebis(3-methyl-6-tert-butylphenyl-di-tridecyl)phosphite 'marketed by ADEKA ARGUS
CHEMICAL under the trademark Mark P; tris(monononyl (HM 5198 + HM 5238 EST) - 14 -phenyl)phosphite; bis(2,4-di-tert-butyl)-pentaerythritol diphosphite, marketed by BORG-WARNER CHEMICAL under the trademark Ultranox 626.
A preferred example of phosphonites is the tetrakis(2,4-di-tert-butylphenyl)4,4'-diphenylilenediphosphonite, on which Sandostab P-EPQ, marketed by Sandoz, is based.
The HALS ara monomeric or oligomeric compounds containing in the molecule one or more substituted amine, preferably piperidine, groups.
Specific examples of HALS containing substituted piperidine groups are the compounds sold by CIBA-GEIGY under the following trademarks:
Chimassorb 944 Chimassorb 905 Tinuvin 770 Tinuvin 292 Tinuvin 622 Tinuvin 144 Spinuvex A36 and the product sold by American CYANAMID under the mark Cyasorb UV 3346.
Examples of phenolic antioxidants are: tris-(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)-s-triazine-2-4-6-(1H,3H,5H)-trione, marketed by American CYANAMID under the trademark Cyanox 1790; calcium bi[monoethyl(3,5-di-tert-butyl-(HM 5198 + HM 5238 EST) - 15 -_ -- 212fi413 4-hydroxy-benzyl)phosphonate];1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)-s-triazine-2,4,6(1H,3H,5H)trione; 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene;
pentaerythrityl-tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]; octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)-propionate, marketed by CIBA GEIGY under the trademarks Irganox 1425; Irganox 3114; Irganox 1330, Irganox 1010, Irganox 1076 respectively; 2,6-dimethyl-3-hydroxy-4-tert-butyl benzyl abietate.
The following examples are given in order to illustrate and not limit the present invention.
EVALUATION OF THE THERMOWELDABILIT'Y OF THE FIBERS
Generally, in order to evaluate the thermoweldability of fibers, a nonwoven fabric is prepared from the fiber being tested by calendering under certain given conditions.
Subsequently, the tension needed to tear said nonwoven fabric both in the direction parallel and transversal to the calendering is measured.
The tension value determined in this fashion is considered a measure of the fiber thermowelding capability.
The result, however, is influenced substantially by the finishing characteristics of the fibers (crimping, surface finishing, thermosetting, etc.), <~nd by the homogeneity of distribution of the fibers entering the calender. To avoid these inconveniences and obtain a more direct evaluation of the (HM 5198 + HM 5238 EST) - 16 -fiber thermoweldability characteristics a method has been perfected that will be described below.
Specimens are prepared from a 400 tex roving (method ASTM
D 1577-7) 0.4 meter long, made up of continuous fibers.
After the roving has been twisted eighty times, the two extremities are united, thus obtaining a product where the two halves of the roving are entwined as in a rope.
The thermowelding is carried out on said specimen using a Bruggel HSC-ETK#thermowelding machine, operating at a plate temperature of 150°C, using a clamping pressure of 800 N and 1 second welding times.
A dynamometer is used to measure the average strength required to separate the two halves of the roving which constitute each specimen at the thermowelding point. The result, expressed in Newton, is obtained by averaging out at least eight measurements, and represents the thermowelding strength of the fibers.
POLYMERS SUBJECTED TO SPINNING
The polymers used in the exannples to produce the fibers are the following:
Polypropylene I
Mechanical mixture of propylE~ne homopolymer having MFRh of 13 g/10 min and a fraction soluble in xylene at 25°C equal to 3 . 5 0 by weight, in the form o:E flakes with a controlled particle size distribution (average diameter of the particles * Trademark - 17 -fB
_.. ~ 2126p'3 450~.m) , containing:
additive concentration (by weight) Irganox 1076* 0.01%
Irganox 3114* 0.01%
Irgafos 168* 0 . 07 Calcium stearate 0.05%
Said mechanical mixture has been obtained by introducing the components into a CACCIA speed mixer model LABO 30, and mixing for 4 minutes at 1400 rpm.
Polypropylene II
Same composition as for Polypropylene I, but in the form of pellets, as the above said mechanical mixture has been granulated by extrusion.
Polypropylene III
Propylene homopolymer in spheroidal particle form with a diameter ranging from 2 to 3 mm, having a MFR of 12.2 g/10 min.
and a fraction soluble in xylene at 25°C equal to 4.2% by weight, surface additivated with:
additive concentration (by weight) Irganox 1076 0.01%
Chimassorb 944 0.02%
Sandostab P-EPQ 0.05%
Calcium stearate 0.05%
* Trademark (B
212gp ~3 The Chimassorb 944 is a HALS having the formula N w_t~Nz-~-N
G
N N 1_ N.
l I
NH ~ N
n wherein n generally ranges from 2 to 20.
Comparative Example 1 Using the above defined polypropylene I, staple fibers are prepared on a LEONARD 25* long spinning apparatus, built and marketed by Costruzioni Meccaniche Leonard - Sumirago (VA) -Italy. The set-up of the apparatus is as follows:
- extruder with a screw having a 25 mm diameter and a length/diameter ratio of 25, a:nd a flow-rate ranging from 1 to 6 Kg/h;
- 2.5 cm'/rev. metering pump;
- die having 61 round holes with an output diameter of 0.8 mm;
- cooling system for the extruded filaments by means of transversal air jet at 18-20°C;
- gathering apparatus with a spE~ed ranging from 1000-6000 m/min.;
- drawing apparatus in steam oven.
The following process conditions are used for the spinning t~3 operation:
* Trademark - die temperature 280°C
- hole flow rate 0.3 g/min.
- gathering speed 1400 m/min.
- draw ratio 1.3 - draw temperature 100°C
The characteristics of the fibE~rs obtained in this manner are:
- single fiber count 1.7 dtex (according to ASTM D 1577-79) - weldability 4.1 N
Example 1 Using the above defined polypropylene I, staple fibers .
with a short-spinning pilot apparatus set up as follows are prepared:
- single-screw extruder with a 120mm diameter and a length equal to 30 diameters;
- 150 cm'/rev. metering pump;
r - die with 3.5x104 round holes a:nd a 0.6 mm output diameter;
said holes being situated in the form of a crown;
- cooling device, coaxial to thf~ crown of holes of the die, emitting 20°C air on a plane perpendicular to the exiting fibers.
The spinning conditions are as follows:
- temperature 300°C
- hole flow rate 0.018 g/min.
- distance between the die and cooling airflow 5 mm - gathering speed 70 m/min.
- draw temperature 80°C
- draw ratio 1.4 The characteristics of the fibers obtained in this manner are:
- single fiber count 2.3 dtex - weldability 6.85 N
Example 2 The same apparatus and conditions of Example 1 are used to produce staple fibers, except that one uses the polypropylene III.
The characteristics of the fibers obtained in this manner are:
- single fiber count 2.3 dtex - weldability 6.5 N
tB
2~26p ~~
Example 3 Staple fibers are produced using the same polymer, apparatus and conditions of Example 1, except that the distance between the die and the cooling airflow is 15 mm.
The characteristics of the fibers obtained in this manner are:
- single fiber count 2.3 dtex - weldability 7.6 N
Example 4 Staple fibers are produced using the same polymer, apparatus and conditions of Examples 1, except that the drawing occurs at ambient temperature.
The characteristics of the fibers obtained in this manner are:
- single fiber count 2.3 dtex - weldability 10 N
Comparative Example 2 Staple fibers are produced using the same polymer of Example 1, an industrial apparatus made up of 8 spinning units identical to the one described in Example 1, but whose dies have 5.18x104 round holes having a output diameter of 0.4 mm.
The spinning conditions are:
- temperature 285°C
- hole flow rate 0.018 g/min.
- distance between the die and tB
cooling airflow 5 mm - gathering speed 64 m/min.
- draw temperature g0°C
- draw ratio 1.5 The characteristics of the fibers obtained in this manner are:
- single fiber count 2.3 dtex - weldability 2.35 N
Comparative Example 3 The same apparatus and conditions of Comparative example 2 are used to produce staple fibers, except that polypropylene III is used.
The spinning conditions are:
- temperature 295°C
- hole draw ratio 0.024 g/min.
- distance between the die and cooling airflow 5 mm - gathering speed 70 m/min.
- draw temperature 80°C
- draw ratio 1.35 The characteristics of the fibers obtained in this manner are:
- single fiber count 2.3 dtex - weldability 2.2 N
Example 5 CB
~- 2~zsa13 Using polypropylene I, fibers are prepared using a BARMAG
25 mod. 2E1/24D apparatus for spun-bonding, manufactured and sold by BARMER MASHINENFABRIK A.G. Manufacture. The lay out of the apparatus is as follows:
- an extruder with a screw 25 mm in diameter and a ratio lenght/diameter of 24; the extruder has a flow rate between 0.3 and 1.2 kg/hr;
- a metering pump of 0.6 cm3/rev.
- a die with 37 holes of circular section having a output hole diameter of 0.8 mm;
- a cooling system for the extruded fibers by transverse air jet at 18-20°C;
- an air suction gathering device using a Venturi tube, with a gathering speed ranging between 500-4000 m/min.
The process conditions for spinning are as follows:
- die temperature 280°C
- hole flow rate 0.6 g/min.
- gathering speed 2700 m/min.
- distance between the die and and the cooling air jet. 20 mm The characteristics of the obtained fibers are:
- single fiber count 2.2 dtex - weldability 5.4 N
Comparison example 4 The same polymer is used, with the same apparatus and (HM 5198 + HM 5238 EST) - 24 -working under the same conditions as in Example 5, except that the die has 37 circular section holes with a output hole diameter of 0.4 mm.
The characteristics of the obtained fibers are:
single fiber count 2.2 dtex - weldability 2.04 N
Example 6 Using polypropylene II, fibers and nonwoven fabrics are prepared with a pilot appartus for spun-bonding made by the German company LURGI. The layout: of the apparatus is as follows rectangular dies containing 931 holes of circular section and with a output hole diameter of 0.9 mm.
- an air cooling device at 20°C, acting on a plane perpendicular to the emergent fibers.
The spinning conditions are as fol:Lows:
- temperature 280°C
- hole flow rate 0.52 g/min.
- distance between the die and the cooling air flow 30 mm - gathering speed 2300 m/min.
The fibers obtained under these conditions have the following characteristics:
- single fiber count 2.3 dtex - weldability 6.4 N
Example 7 Fibers are produced with the same apparatus and working under the same conditions as in Example 5, but using polypropylene III.
The obtained fibers have the following characteristics:
- single fiber count 2.2 dtex - weldability 5.8 N
Comparison Example 5 Fibers are produced with the ~~ame polymer used in Example 7~ and the same apparatus used :in Example 5, but the die contains 37 holes of circular section and the output hole diameter is equal to 0.4 mm.
The obtained fibers have the following characteristics:
- single fiber count 2.2 dtex - weldability 2.1 N
Preferably the amount of dime in (B) is from 1% to 10%
by weight.
The heterophasic copolymers (a) are prepared according to known methods by mixing the components in the molten state, or by sequential copolymerization, and generally contain the copolymer fraction (B) in quantities ranging from 5% to 80% by weight.
Specific examples of olefin polymers particularly suitable for the preparation of thermoweldable fibers are the following propylene random copolymers:
a) crystalline propylene random copolymers containing from 1 . 5 % to 20 % by weight of ethy:Lene or C4-Ca alpha-olefins;
b) crystalline propylene random copolymers containing from 85 % to 96 % by weight of propylene, from 1 . 5 % to 5% by weight of ethylene, and from 2.5% to 10% by weight of a C4-C8 alpha- olefin;
c) crystalline propylene random copolymers compositions comprising (percentages by weight):
(1) from 30% to 65% of a copolymer of propylene with a (HM 5198 + HM 5238 EST) - 10 -~_ zzzsa~3 C4-C8 alpha-olefin, containing from 80% to 98% of propylene; and (2) from 35% to 70% of a propylene copolymer with ethylene, and optionally with a C4-Cg alpha-olefin in quantity ranging from 2% to 10%; said copolymer containing from 2 % to 10%' of ethylene when the above mentioned C4-CB alpha-olei_in is not present, and from 0 . 5 % to 5 % of ethylene when the C4-Cg alpha-olef in is present;
d) compositions of crystalline propylene random copolymers and crystalline ethylene copolymers comprising (percentages by weight) (1) from 40% to 70% of one or more crystalline propylene copolymers with one or more comonomers selected from ethylene and/or C4-CA alpha-olefin, wherein the comonomer or comonomers content is from 5% to 20%;
(2) from 30% to 60% of LLDPE having a MFR E (according to ASTM D 1238) from 0.1 to 15.
The above mentioned copolymers can also be used mixed with each other and/or with isotactic or mainly isotactic propylene homopolymers.
Other specific examples of olefin polymers particularly suitable for the preparation of thermoweldable fibers are heterophasic copolymers comprising from 5% to 95 % by weight of an isotactic or mainly isotactic propylene homopolymer, and/or (HM 5198 + HM 5238 EST) - 11 -a random propylene copolymer of the above mentioned types from a) to d), and from 95% to 5% by weight of a composition selected from:
(I) a composition comprising:
(i) 10-60 parts by weight of propylene homopolymer with an isotactic index higher than 90, or of a crystalline copolymer of propylene with ethylene and/or another C4-C8 alpha-olefin, containing over 85% by weight of propylene, and having an isotactic index higher than 85;
(ii) 10-40 parts by weight of a crystalline polymer fraction containing ethylene, insoluble in xylene at ambient temperature;
(iii) 30-60 parts by weight of an amorphous ethylene-propylene copolymer fraction optionally containing minor portions of a diene, soluble in xylene at ambient temperature and containing from 40 to 70% by weight of ethylene;
(II) a composition comprising:
(i) 10-50 parts by weight of propylene homopolymer with an isotactic index higher than 80, or a copolymer of propylene with ethylene and/or a C4-CB alpha-olefin containing over 85% by weight of propylene;
(ii) 5-20 parts by weight of a copolymer fraction containing ethylene, insoluble in xylene at ambient (HM 5198 + HM 5238 EST) - 12 -212601.3 temperature;
(iii) 40-80 parts by weight ~of a copolymer fraction of ethylene with propylene and/or a C4-CB alpha-olefin, and optionally with minor portions of dime, containing less than 40s by weight of ethylene, said fraction being soluble in xylene at ambient temperature, and havin~3 an intrinsic viscosity ranging from 1.5 to 4 dl/g.
Specific examples of C4-CB alpha olefins and dienes have been given above.
Generally, when used in the production of staple fibers the above mentioned olefin polymers have a Melt Flow Rate (MFR), determined according to ASTNID 1238-L, ranging from 0.5 to 100 g/10 min., preferably from 1.5 to 35 g/10 min..
When used in the spun-bonding apparatuses with the process of the present invention, the above. mentioned olefin polymers have preferably a MFR value between 5 and 25 g/10 min., in particular from 8 to 15 g/10 min.. These values of MFR
constitute an additional distinctive feature of the process of the invention, because in conventional spun-bonding processes polyolefins have a MFR greater than 25 g/10 min.
The above said values of MFR. are obtained directly in polymerization, or by controlled degradation. In order to obtain said controlled degradation c:~e adds, for example, organic peroxides in the spinning line or in the preceding (HM 5198 + HM 5238 EST) - 13 -. _. _ __.__ ...~_5.*~:,.__ __....,".....~.. _ __ . _. . _ , _ ...:
steps of pelletization of the olefin polymers. Olefin polymers are generally used in the form of pellets or nonextruded particles, such as flakes or spheres, for example.
Preferably the olefin polymers which are subjected to spinning with either process of the present invention are stabilized with the types and ~xuantities of stabilizers described in published European patent application 391438.
According to said patent application the polyolefins to be used for spinning contain one or more of the following stabilizers a) from 0.01 to 0.5o by weight: of one or more organic phosphites and/or phosphonites;
b) from 0.005 to 0.5% by weight of one or more HALS
(Hindered Amine Light Stabilizer);
and optionally one or more phenolic antioxidants in concentration which does not exceed 0.02% by weight.
The above stabilizers car. be added to the polyolefins by means of pelletization or surface coating, or they can be mechanically mixed with the polyole~fins.
Specific examples of phosphite~s are:
tris(2,4-di-tert-butylphenyl)phosph.ite marketed by CIBA GEIGY
under the trademark Irgafos 168; distearyl pentaerythritol diphosphite marketed by BORG-WA~tNER CHEMICAL under the trademark Weston 618; 4,4'-buty:Lidenebis(3-methyl-6-tert-butylphenyl-di-tridecyl)phosphite 'marketed by ADEKA ARGUS
CHEMICAL under the trademark Mark P; tris(monononyl (HM 5198 + HM 5238 EST) - 14 -phenyl)phosphite; bis(2,4-di-tert-butyl)-pentaerythritol diphosphite, marketed by BORG-WARNER CHEMICAL under the trademark Ultranox 626.
A preferred example of phosphonites is the tetrakis(2,4-di-tert-butylphenyl)4,4'-diphenylilenediphosphonite, on which Sandostab P-EPQ, marketed by Sandoz, is based.
The HALS ara monomeric or oligomeric compounds containing in the molecule one or more substituted amine, preferably piperidine, groups.
Specific examples of HALS containing substituted piperidine groups are the compounds sold by CIBA-GEIGY under the following trademarks:
Chimassorb 944 Chimassorb 905 Tinuvin 770 Tinuvin 292 Tinuvin 622 Tinuvin 144 Spinuvex A36 and the product sold by American CYANAMID under the mark Cyasorb UV 3346.
Examples of phenolic antioxidants are: tris-(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)-s-triazine-2-4-6-(1H,3H,5H)-trione, marketed by American CYANAMID under the trademark Cyanox 1790; calcium bi[monoethyl(3,5-di-tert-butyl-(HM 5198 + HM 5238 EST) - 15 -_ -- 212fi413 4-hydroxy-benzyl)phosphonate];1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)-s-triazine-2,4,6(1H,3H,5H)trione; 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene;
pentaerythrityl-tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]; octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)-propionate, marketed by CIBA GEIGY under the trademarks Irganox 1425; Irganox 3114; Irganox 1330, Irganox 1010, Irganox 1076 respectively; 2,6-dimethyl-3-hydroxy-4-tert-butyl benzyl abietate.
The following examples are given in order to illustrate and not limit the present invention.
EVALUATION OF THE THERMOWELDABILIT'Y OF THE FIBERS
Generally, in order to evaluate the thermoweldability of fibers, a nonwoven fabric is prepared from the fiber being tested by calendering under certain given conditions.
Subsequently, the tension needed to tear said nonwoven fabric both in the direction parallel and transversal to the calendering is measured.
The tension value determined in this fashion is considered a measure of the fiber thermowelding capability.
The result, however, is influenced substantially by the finishing characteristics of the fibers (crimping, surface finishing, thermosetting, etc.), <~nd by the homogeneity of distribution of the fibers entering the calender. To avoid these inconveniences and obtain a more direct evaluation of the (HM 5198 + HM 5238 EST) - 16 -fiber thermoweldability characteristics a method has been perfected that will be described below.
Specimens are prepared from a 400 tex roving (method ASTM
D 1577-7) 0.4 meter long, made up of continuous fibers.
After the roving has been twisted eighty times, the two extremities are united, thus obtaining a product where the two halves of the roving are entwined as in a rope.
The thermowelding is carried out on said specimen using a Bruggel HSC-ETK#thermowelding machine, operating at a plate temperature of 150°C, using a clamping pressure of 800 N and 1 second welding times.
A dynamometer is used to measure the average strength required to separate the two halves of the roving which constitute each specimen at the thermowelding point. The result, expressed in Newton, is obtained by averaging out at least eight measurements, and represents the thermowelding strength of the fibers.
POLYMERS SUBJECTED TO SPINNING
The polymers used in the exannples to produce the fibers are the following:
Polypropylene I
Mechanical mixture of propylE~ne homopolymer having MFRh of 13 g/10 min and a fraction soluble in xylene at 25°C equal to 3 . 5 0 by weight, in the form o:E flakes with a controlled particle size distribution (average diameter of the particles * Trademark - 17 -fB
_.. ~ 2126p'3 450~.m) , containing:
additive concentration (by weight) Irganox 1076* 0.01%
Irganox 3114* 0.01%
Irgafos 168* 0 . 07 Calcium stearate 0.05%
Said mechanical mixture has been obtained by introducing the components into a CACCIA speed mixer model LABO 30, and mixing for 4 minutes at 1400 rpm.
Polypropylene II
Same composition as for Polypropylene I, but in the form of pellets, as the above said mechanical mixture has been granulated by extrusion.
Polypropylene III
Propylene homopolymer in spheroidal particle form with a diameter ranging from 2 to 3 mm, having a MFR of 12.2 g/10 min.
and a fraction soluble in xylene at 25°C equal to 4.2% by weight, surface additivated with:
additive concentration (by weight) Irganox 1076 0.01%
Chimassorb 944 0.02%
Sandostab P-EPQ 0.05%
Calcium stearate 0.05%
* Trademark (B
212gp ~3 The Chimassorb 944 is a HALS having the formula N w_t~Nz-~-N
G
N N 1_ N.
l I
NH ~ N
n wherein n generally ranges from 2 to 20.
Comparative Example 1 Using the above defined polypropylene I, staple fibers are prepared on a LEONARD 25* long spinning apparatus, built and marketed by Costruzioni Meccaniche Leonard - Sumirago (VA) -Italy. The set-up of the apparatus is as follows:
- extruder with a screw having a 25 mm diameter and a length/diameter ratio of 25, a:nd a flow-rate ranging from 1 to 6 Kg/h;
- 2.5 cm'/rev. metering pump;
- die having 61 round holes with an output diameter of 0.8 mm;
- cooling system for the extruded filaments by means of transversal air jet at 18-20°C;
- gathering apparatus with a spE~ed ranging from 1000-6000 m/min.;
- drawing apparatus in steam oven.
The following process conditions are used for the spinning t~3 operation:
* Trademark - die temperature 280°C
- hole flow rate 0.3 g/min.
- gathering speed 1400 m/min.
- draw ratio 1.3 - draw temperature 100°C
The characteristics of the fibE~rs obtained in this manner are:
- single fiber count 1.7 dtex (according to ASTM D 1577-79) - weldability 4.1 N
Example 1 Using the above defined polypropylene I, staple fibers .
with a short-spinning pilot apparatus set up as follows are prepared:
- single-screw extruder with a 120mm diameter and a length equal to 30 diameters;
- 150 cm'/rev. metering pump;
r - die with 3.5x104 round holes a:nd a 0.6 mm output diameter;
said holes being situated in the form of a crown;
- cooling device, coaxial to thf~ crown of holes of the die, emitting 20°C air on a plane perpendicular to the exiting fibers.
The spinning conditions are as follows:
- temperature 300°C
- hole flow rate 0.018 g/min.
- distance between the die and cooling airflow 5 mm - gathering speed 70 m/min.
- draw temperature 80°C
- draw ratio 1.4 The characteristics of the fibers obtained in this manner are:
- single fiber count 2.3 dtex - weldability 6.85 N
Example 2 The same apparatus and conditions of Example 1 are used to produce staple fibers, except that one uses the polypropylene III.
The characteristics of the fibers obtained in this manner are:
- single fiber count 2.3 dtex - weldability 6.5 N
tB
2~26p ~~
Example 3 Staple fibers are produced using the same polymer, apparatus and conditions of Example 1, except that the distance between the die and the cooling airflow is 15 mm.
The characteristics of the fibers obtained in this manner are:
- single fiber count 2.3 dtex - weldability 7.6 N
Example 4 Staple fibers are produced using the same polymer, apparatus and conditions of Examples 1, except that the drawing occurs at ambient temperature.
The characteristics of the fibers obtained in this manner are:
- single fiber count 2.3 dtex - weldability 10 N
Comparative Example 2 Staple fibers are produced using the same polymer of Example 1, an industrial apparatus made up of 8 spinning units identical to the one described in Example 1, but whose dies have 5.18x104 round holes having a output diameter of 0.4 mm.
The spinning conditions are:
- temperature 285°C
- hole flow rate 0.018 g/min.
- distance between the die and tB
cooling airflow 5 mm - gathering speed 64 m/min.
- draw temperature g0°C
- draw ratio 1.5 The characteristics of the fibers obtained in this manner are:
- single fiber count 2.3 dtex - weldability 2.35 N
Comparative Example 3 The same apparatus and conditions of Comparative example 2 are used to produce staple fibers, except that polypropylene III is used.
The spinning conditions are:
- temperature 295°C
- hole draw ratio 0.024 g/min.
- distance between the die and cooling airflow 5 mm - gathering speed 70 m/min.
- draw temperature 80°C
- draw ratio 1.35 The characteristics of the fibers obtained in this manner are:
- single fiber count 2.3 dtex - weldability 2.2 N
Example 5 CB
~- 2~zsa13 Using polypropylene I, fibers are prepared using a BARMAG
25 mod. 2E1/24D apparatus for spun-bonding, manufactured and sold by BARMER MASHINENFABRIK A.G. Manufacture. The lay out of the apparatus is as follows:
- an extruder with a screw 25 mm in diameter and a ratio lenght/diameter of 24; the extruder has a flow rate between 0.3 and 1.2 kg/hr;
- a metering pump of 0.6 cm3/rev.
- a die with 37 holes of circular section having a output hole diameter of 0.8 mm;
- a cooling system for the extruded fibers by transverse air jet at 18-20°C;
- an air suction gathering device using a Venturi tube, with a gathering speed ranging between 500-4000 m/min.
The process conditions for spinning are as follows:
- die temperature 280°C
- hole flow rate 0.6 g/min.
- gathering speed 2700 m/min.
- distance between the die and and the cooling air jet. 20 mm The characteristics of the obtained fibers are:
- single fiber count 2.2 dtex - weldability 5.4 N
Comparison example 4 The same polymer is used, with the same apparatus and (HM 5198 + HM 5238 EST) - 24 -working under the same conditions as in Example 5, except that the die has 37 circular section holes with a output hole diameter of 0.4 mm.
The characteristics of the obtained fibers are:
single fiber count 2.2 dtex - weldability 2.04 N
Example 6 Using polypropylene II, fibers and nonwoven fabrics are prepared with a pilot appartus for spun-bonding made by the German company LURGI. The layout: of the apparatus is as follows rectangular dies containing 931 holes of circular section and with a output hole diameter of 0.9 mm.
- an air cooling device at 20°C, acting on a plane perpendicular to the emergent fibers.
The spinning conditions are as fol:Lows:
- temperature 280°C
- hole flow rate 0.52 g/min.
- distance between the die and the cooling air flow 30 mm - gathering speed 2300 m/min.
The fibers obtained under these conditions have the following characteristics:
- single fiber count 2.3 dtex - weldability 6.4 N
Example 7 Fibers are produced with the same apparatus and working under the same conditions as in Example 5, but using polypropylene III.
The obtained fibers have the following characteristics:
- single fiber count 2.2 dtex - weldability 5.8 N
Comparison Example 5 Fibers are produced with the ~~ame polymer used in Example 7~ and the same apparatus used :in Example 5, but the die contains 37 holes of circular section and the output hole diameter is equal to 0.4 mm.
The obtained fibers have the following characteristics:
- single fiber count 2.2 dtex - weldability 2.1 N
Claims (21)
1. A process for the preparation of thermoweldable polyolefin staple fibers, comprising spinning an olefin polymer at a gathering speed of from 40 to 250 m/min. using a short-spinning apparatus including dies with holes, each hole having a real or equivalent output diameter of 0.5 mm or more, the ratio of said output diameter of the holes to the count being greater than or equal to 0.06 mm/dtex for the preparation of fibers having a count greater than or equal to 4 dtex.
2. A process for the preparation of thermoweldable polyolefin staple fibers having a count ranging from 0.5 to
3 dtex, comprising spinning an olefin polymer at a gathering speed of from 40 to 250 m/min. using a short-spinning apparatus including dies with holes, each hole having a real or equivalent output diameter ranging from 0.5 to 2 mm.
3. The process of claim 1, wherein the real or equivalent output diameter of the roles ranges from 0.5 to 2 mm.
3. The process of claim 1, wherein the real or equivalent output diameter of the roles ranges from 0.5 to 2 mm.
4. The process of claim 1, 2 or 3, wherein a hole flow rate ranges from 0.005 to 0.18 g/min., the fiber gathering speed ranges from 50 to 100 m/min., and a draw ratio ranges from 1.10 to 3.50.
5. The process of any one of claims 1 to 4, wherein a spinning temperature ranges from. 240 to 310°C.
6. The process of claim 5, wherein the spinning temperature ranges from 270 to 300°C.
7. The process of any one of claims 1 to 6, wherein a draw temperature used is lower than 100°C.
8. The process of any one of claims 1 to 7, wherein the olefin polymer subjected to spinning has a MFR from 1.5 to 35 g/10 min.
9. A process for the preparation of thermoweldable polyolefin fibers, comprising spinning an olefin polymer using a spun-bonding apparatus including dies with holes, each hole having a real or equivalent output diameter of 0.5 mm or more, the ratio of said output diameter of the holes to the count being greater than or equal to 0.06 mm/dtex for the preparation of fibers having a count greater than or equal to 4 dtex.
10. A process for the preparation of thermoweldable polyolefin fibers having a count ranging from 0.5 to 3 dtex, comprising spinning an olefin polymer using a spun-bonding apparatus including dies with holes, each hole having a real or equivalent output diameter ranging from 0.5 to 2 mm.
11. The process of claim 9, wherein the real or equivalent output diameter of the holes ranges from 0.5 to 2 mm.
12. The process of any one of claims 9 to 11, wherein a hole flow rate ranges from 0.1 to 2.0 g/min. and a fiber gathering speed ranges from 400 to 4500 m/min.
13. The process of any one of claims 9 to 12, wherein the olefin polymer subjected to spinning has a MFR from 5 to 25 g/10 min.
14. The process of claim 13, wherein the olefin polymer subjected to spinning has a MFR from 8 to 15 g/10 min.
15. The process of any one of claims 9 to 14, wherein a spinning temperature is between 230 and 300°C.
16. The process of claim 15, wherein the spinning temperature is between 240 and 280°C.
17. The process of any one of claims 1 to 16, wherein a cooling space is greater than 2 mm.
18. The process of any one of claims 1 to 17, wherein the olefin polymer subjected to spinning is selected from:
1) isotactic, or mainly isotactic propylene homopolymers;
2) crystalline copolymers of propylene with ethylene and/or C4-C8 alpha-olefins, wherein the total comonomer content ranges from 0.05% to 20% by weight, or mixtures of said copolymers with isotactic or mainly isotactic propylene homopolymers;
3) heterophasic copolymers comprising (A) a propylene homopolymer and/or one of the copolymers of item 2), and an elastomeric fraction (B) comprising coploymers of ethylene with propylene and/or a C4-C8 alpha-olefin, optionally containing minor quantities of a diene.
1) isotactic, or mainly isotactic propylene homopolymers;
2) crystalline copolymers of propylene with ethylene and/or C4-C8 alpha-olefins, wherein the total comonomer content ranges from 0.05% to 20% by weight, or mixtures of said copolymers with isotactic or mainly isotactic propylene homopolymers;
3) heterophasic copolymers comprising (A) a propylene homopolymer and/or one of the copolymers of item 2), and an elastomeric fraction (B) comprising coploymers of ethylene with propylene and/or a C4-C8 alpha-olefin, optionally containing minor quantities of a diene.
19. The process of any one of claims 1 to 18, wherein the olefin polymer subjected to spanning contains one or more of the following stabilizers:
a) from 0.01 to 0.5% by weight of one or more organic phospites and/or phosphonites;
b) from 0.005 to 0.5% by weight of one or more HALS.
a) from 0.01 to 0.5% by weight of one or more organic phospites and/or phosphonites;
b) from 0.005 to 0.5% by weight of one or more HALS.
20. The process of any one of: claims 1 to 19, wherein the ratio of said output diameter of the holes to the count is greater than or equal to 0.08 mm/dtex.
21. The process of any one of claims 1 to 20, wherein the ratio of said output diameter of the holes to the count is greater than or equal to 0.1 mm/dtex.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| ITMI93A001308 | 1993-06-17 | ||
| IT93MI1308 IT1264839B1 (en) | 1993-06-17 | 1993-06-17 | Spinning process for prodn. of thermo:weldable polyolefin fibres - provides nonwoven fabrics with good softness and tear resistance e.g. cover:stock for nappy |
| IT000390 IT1274029B (en) | 1994-03-04 | 1994-03-04 | Spinning process for prodn. of thermo:weldable polyolefin fibres - provides nonwoven fabrics with good softness and tear resistance e.g. cover:stock for nappy |
| ITMI94A00390 | 1994-03-04 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2126013A1 CA2126013A1 (en) | 1994-12-18 |
| CA2126013C true CA2126013C (en) | 2000-08-15 |
Family
ID=26331006
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002126013A Expired - Fee Related CA2126013C (en) | 1993-06-17 | 1994-06-16 | Spinning process for the preparation of high termoweldability polyolefin fibers |
Country Status (12)
| Country | Link |
|---|---|
| EP (1) | EP0629720B1 (en) |
| JP (1) | JP2849042B2 (en) |
| KR (1) | KR100199683B1 (en) |
| CN (1) | CN1069352C (en) |
| AT (1) | ATE162860T1 (en) |
| CA (1) | CA2126013C (en) |
| DE (1) | DE69408213T2 (en) |
| DK (1) | DK0629720T3 (en) |
| ES (1) | ES2113579T3 (en) |
| FI (1) | FI942889A (en) |
| HK (1) | HK1008435A1 (en) |
| TW (1) | TW270153B (en) |
Families Citing this family (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5773375A (en) * | 1996-05-29 | 1998-06-30 | Swan; Michael D. | Thermally stable acoustical insulation |
| DE59812014D1 (en) * | 1997-05-14 | 2004-11-04 | Borealis Gmbh Schwechat Mannsw | Polyolefin fibers and polyolefin yarns and textile fabrics made from them |
| DE19720135B4 (en) * | 1997-05-14 | 2005-12-08 | Borealis Gmbh | Non-postdrawn polyolefin fibers and high tenacity and elongated polyolefin yarns and fabrics made therefrom |
| DE19722579B4 (en) * | 1997-05-30 | 2004-02-12 | Borealis Gmbh | Fibers and yarns of high tenacity and elongation, process for their production and use |
| US5948334A (en) * | 1997-07-31 | 1999-09-07 | Fiberco, Inc. | Compact long spin system |
| US5858293A (en) * | 1997-09-30 | 1999-01-12 | Montell North America Inc. | Method for producing spunbonded materials with improved tensile strength |
| CA2419187A1 (en) * | 2000-10-11 | 2002-04-18 | Jeffrey D. Malcom | High strength spunbond fabric |
| MXPA03006783A (en) * | 2001-02-02 | 2004-10-15 | Polymer Group Inc | Process for producing continuous filament nonwoven fabric. |
| US6787066B2 (en) * | 2001-11-16 | 2004-09-07 | Sunoco Inc (R&M) | Stabilization system for improving the melt viscosity of polypropylene during fiber processing |
| WO2017186935A1 (en) | 2016-04-29 | 2017-11-02 | Beaulieu International Group Nv | Bi-component staple or short-cut trilobal fibres and their uses |
| CN107880400A (en) * | 2016-09-29 | 2018-04-06 | 中国石油化工股份有限公司 | A kind of impact polypropylene resin with low tension fracture elongation rate |
| KR102631607B1 (en) | 2023-07-19 | 2024-01-31 | 공필주 | One-touch fastening type separable communication |
Family Cites Families (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2545223C3 (en) * | 1975-10-09 | 1978-03-30 | Basf Ag, 6700 Ludwigshafen | Self-extinguishing thermoplastic molding compounds |
| JPS53147816A (en) * | 1977-05-24 | 1978-12-22 | Chisso Corp | Hot-melt fiber of polypropylene |
| JPS575913A (en) * | 1980-05-27 | 1982-01-12 | Showa Electric Wire & Cable Co Ltd | Crosslinked polyolefin fiber |
| JPS58144113A (en) * | 1982-02-16 | 1983-08-27 | Taisei Rayon Kk | Production of polyethylene multifilament yarn for fish net |
| JPS61239011A (en) * | 1985-04-15 | 1986-10-24 | Kanebo Ltd | Conductive synthetic fiber of polyolefin and production thereof |
| JPS62282014A (en) * | 1986-05-30 | 1987-12-07 | Seiken:Kk | Production of fiber |
| IT1229141B (en) * | 1989-04-06 | 1991-07-22 | Himont Inc | POLYOLEFINS SUITABLE FOR SPINNING AND THERMAL SEALABLE FIBERS OBTAINED FROM THEM. |
| EP0552013B1 (en) * | 1992-01-13 | 1999-04-07 | Hercules Incorporated | Thermally bondable fiber for high strength non-woven fabrics |
-
1994
- 1994-06-16 CA CA002126013A patent/CA2126013C/en not_active Expired - Fee Related
- 1994-06-16 KR KR1019940013636A patent/KR100199683B1/en not_active IP Right Cessation
- 1994-06-16 FI FI942889A patent/FI942889A/en unknown
- 1994-06-17 EP EP94109406A patent/EP0629720B1/en not_active Expired - Lifetime
- 1994-06-17 JP JP6159156A patent/JP2849042B2/en not_active Expired - Fee Related
- 1994-06-17 TW TW083105487A patent/TW270153B/zh active
- 1994-06-17 DK DK94109406T patent/DK0629720T3/en active
- 1994-06-17 DE DE69408213T patent/DE69408213T2/en not_active Expired - Fee Related
- 1994-06-17 ES ES94109406T patent/ES2113579T3/en not_active Expired - Lifetime
- 1994-06-17 AT AT94109406T patent/ATE162860T1/en not_active IP Right Cessation
- 1994-06-17 CN CN94107510A patent/CN1069352C/en not_active Expired - Fee Related
-
1998
- 1998-07-17 HK HK98109256A patent/HK1008435A1/en not_active IP Right Cessation
Also Published As
| Publication number | Publication date |
|---|---|
| ATE162860T1 (en) | 1998-02-15 |
| CN1069352C (en) | 2001-08-08 |
| FI942889A0 (en) | 1994-06-16 |
| HK1008435A1 (en) | 1999-05-07 |
| EP0629720B1 (en) | 1998-01-28 |
| CN1106867A (en) | 1995-08-16 |
| ES2113579T3 (en) | 1998-05-01 |
| KR100199683B1 (en) | 1999-06-15 |
| TW270153B (en) | 1996-02-11 |
| JPH07189021A (en) | 1995-07-25 |
| EP0629720A3 (en) | 1995-07-12 |
| CA2126013A1 (en) | 1994-12-18 |
| EP0629720A2 (en) | 1994-12-21 |
| JP2849042B2 (en) | 1999-01-20 |
| DE69408213T2 (en) | 1998-07-09 |
| KR950000933A (en) | 1995-01-03 |
| FI942889A (en) | 1994-12-18 |
| DK0629720T3 (en) | 1998-09-23 |
| DE69408213D1 (en) | 1998-03-05 |
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| Date | Code | Title | Description |
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| EEER | Examination request | ||
| MKLA | Lapsed |