KR20000053080A - Monofilaments and their use in producing technical textile articles - Google Patents

Abstract

PURPOSE: Monofilaments is provided to improve the lateral stability, increase the change bending stability and to improve the softness from producible basic fabric or press felts. CONSTITUTION: Monofilaments comprise between 100 and 96 wt % of a thread-forming copolyamide (CPA) or a mixed polyamide (MPA) comprising between 80 and 99 wt % polyamide (PA) 6, and between 1 and 20 wt % of one or a plurality of polyamides selected from the group comprising PA 66, PA 12 and PA 11. The monofilaments are used in preparing technical textile articles, woven textiles, knitted fabrics or felts, in particular conveyer belts, screening textiles, silk-screen printing textiles, moulding screen textiles, press felts and seam press felts, as well as press felts or seam press felts, produced from the monofilaments, for paper manufacture or cellulose manufacture.

Description

Monofilaments and Their Use in Producing Technical Textile Articles}

The present invention relates to a fiber-forming copolyamide (CoPA) or mixture consisting of 80 to 99% by weight of polyamide (PA) 6 and 1 to 20% by weight of at least one polyamide from the group of PA 66, PA 12 and PA 11 It relates to an industrial monofilament having greater flexibility and improved lateral resilience, comprising from 100 to 96% by weight of polyamide (MPA). The invention also relates to the use of industrial monofilaments for the production of industrial textile products, woven, knitted or felt fabrics, in particular conveyor belts, classified screen fabrics, screen printing screen fabrics, molded fabrics, crimped felts and rod crimped felts, And crimped felt or bar crimped felt for making paper or wood pulp made from a single filament.

Methods for producing monofilaments from thermoplastic polymers are generally known from Handbuch der Kunststofftechnik II, C. Hauser Verlag, Munich 1986, pages 295-319.

The literature (Lehrbuch der Papier- und Kartonerzeugung (see VEB Fachbuchverlag 1987) pages 190 and below) includes information on modern papermaking machines consisting of sheet forming (molding compartment), mechanical dehydration (compression compartment) and heating dehydration (dry compartment), smoothing and winding. The papermaking method is described.

The fabric in the forming section is predominantly made of polyester (hereinafter abbreviated as PES). Polyamide (PA) monofilaments with PES monofilaments (as changing wefts on the machine side) are also used to increase wear resistance.

In the compression section, the support fabric for the compression felt or the rod compression felt is mostly exclusively made from polyamide fibers and monofilaments, preferably pure PA 6, but also from PA 66. The polyamide fiber wool layer is then needle-punched with a monofilament support fabric and mechanically attached to the support fabric.

In contrast, drying screens typically consist of PES monofilaments or PAN multifilaments in general.

In particular, the following disadvantages have been found in known industrial monofilaments. In particular, when the single filament fabric is combined with the fiber wool layer by the needle method during paper making, for example, as described above, the single filament is rapidly damaged and the strength of the fabric is undesirably reduced.

The strength of the support fabric after needle puncture is another important parameter that determines, for example, the useful life of a screen or belt made from the support fabric.

Known monofilaments based on PA only and fabrics / felts made therefrom still suffer from excessive loss of strength after needle punching, which greatly shortens the operating time or machine useful life of the felt on the papermaking machine.

Continuous technological advances in the paper sector have resulted in higher technical requirements for crimping felt, and therefore also higher requirements for single filaments required for this purpose. However, it is not possible to use known PA or PES monofilaments to extend the useful life of the felt after needle puncture and to improve the residual strength.

Therefore, the fundamental object of the present invention

The lateral resilience of the single filament and the supporting fabric or crimped felt that can be produced therefrom is improved,

The flexural fatigue strength of the monofilament, and the supporting fabric or crimped felt that can be produced therefrom, is increased,

At least maintained if the flexibility of the monofilament and the supporting fabric or crimping felt that can be produced therefrom is not improved,

-Residual strength of the crimped felt after needle puncture is increased,

-When converting single filament to industrial textile, processing characteristics are not deteriorated.

-Extend the useful life of industrial textiles or crimping felts in paper machines

It is to improve this property of industrial monofilaments.

This object is in accordance with the present invention

a) 80 to 99% by weight of polyamide (PA) 6 and 1 to 20% by weight of at least one polyamide from the group consisting of PA 66, PA 12 and PA 11 or a mixture of fiber-forming copolyamides (CoPA) 100 to 96% by weight of polyamide (MPA), preferably 99.8 to 99% by weight, and

b) 0 to 4.0% by weight, preferably 0.02 to 4.0% by weight, based on the sum of components a) + b)

As a monofilament which is also the subject of the present invention, it is achieved by a novel industrial monofilament having a diameter of 0.05 to 1 mm, in particular 0.1 to 0.8 mm, particularly preferably 0.2 to 0.5 mm.

Auxiliary materials are generally materials known for the manufacture of fibers,

Monomers, oligomers, antioxidants, in particular sterically hindered phenols (SHP), aromatic amines (AA) or copper salts, in particular salts of monovalent copper,

Extrusion aids or mold release agents, in particular Ca, Mg or Zn salts of C ₁₀ -C ₂₂ fatty acids, particularly preferably Mg stearate, Ca stearate, Zn stearate,

Nucleating agents, in particular talcum, and

Colorants, for example dyes and / or pigments

Selected from the group consisting of any desired combination.

Preferred monofilaments are from 99 to 85% by weight of PA 6 and from 15 to 1% by weight of PA 66, preferably from 98 to 90% by weight of PA 6 and from 10 to 2% by weight of PA 66, particularly preferably from 97 to 93% by weight of PA 6 And PA 66 7-3 weight percent; Or 99 to 85 weight percent PA 6 and 15 to 1 weight percent PA 12, preferably 98 to 90 weight percent PA 6 and 10 to 2 weight percent PA 12, particularly preferably 97 to 93 weight percent PA 6 and PA 12 7 to 3 weight percent; Or 99 to 85% by weight of PA 6 and 15 to 1% by weight of PA 11, preferably 98 to 90% by weight of PA 6 and 10 to 2% by weight of PA 11, particularly preferably 98 to 93% by weight of PA 6 and PA 11 It is characterized by copolyamide CoPA or mixed polyamide MPA consisting of 7 to 2% by weight.

Preferred monofilaments also contain from 98 to 80% by weight of PA 6, from 1 to 19% by weight of PA 66 and from 1 to 19% by weight of PA 12, preferably from 98 to 90% by weight of PA 6, from 9 to 1% by weight of PA 66 and to PA 12. 9 to 1 weight percent; Alternatively PA 6 98-80%, PA 66 1-19% and PA 11 1-19%, preferably PA 6 98-90%, PA 66 9-1% and PA 11 9-1% Ternary copolyamide CoPA or mixed polyamide MPA consisting of%.

The invention also

a) 80 to 99% by weight of polyamide (PA) 6 and 1 to 20% by weight of at least one polyamide from the group consisting of PA 66, PA 12 and PA 11 or a mixture of fiber-forming copolyamides (CoPA) 100 to 96% by weight of polyamide (MPA), preferably 99.8 to 99% by weight, and

b) monomers, oligomers for the sum of a) + b); Antioxidants, in particular sterically hindered phenols (SHP), aromatic amines or copper salts, especially salts of monovalent copper; Extrusion aids or molding release agents, in particular Ca, Mg or Zn salts of C ₁₀ -C ₂₂ fatty acids, particularly preferably Mg stearate, Ca stearate, Zn stearate; Nucleating agents, in particular talcum; And 0 to 4.0% by weight, preferably 0.02 to 4.0% by weight, of an auxiliary material selected in any desired combination from the group consisting of colorants, for example dyes and / or pigments.

To provide the use of a single filament for the production of industrial textile products, woven, knitted or felt fabrics.

The monofilaments are preferably so-called industrial textiles, such as industrial textiles and felts, for example conveyor belts, classification screen fabrics, fabrics of screen printing screens, molded fabrics, crimping felts and bar pressing crimping felts, particularly preferably paper or wood Used for pressing felt for making pulp or bar pressing felt.

The monofilaments preferably used are copolyamide CoPA or mixed polyamide MPA having from 99 to 85% by weight of PA 6 and from 15 to 1% by weight of PA 66, preferably from 98 to 90% by weight of PA 6 and from 10 to 2% by weight of PA 66. %, Particularly preferably 97 to 93% by weight of PA 6 and 7 to 3% by weight of PA 66; Or 99 to 85 weight percent PA 6 and 15 to 1 weight percent PA 12, preferably 98 to 90 weight percent PA 6 and 10 to 2 weight percent PA 12, particularly preferably 97 to 93 weight percent PA 6 and PA 12 7 to 3 weight percent; Or 99 to 85% by weight of PA 6 and 15 to 1% by weight of PA 11, preferably 98 to 90% by weight of PA 6 and 10 to 2% by weight of PA 11, particularly preferably 98 to 93% by weight of PA 6 and PA 11 7 to 2% by weight.

In addition, the monofilaments preferably used are PA 6 98 to 80% by weight, PA 66 1 to 19% by weight and PA 12 1 to 19% by weight, preferably PA 6 98 to 90% by weight, PA 66 9 to 1% by weight % And PA 12 9-1 weight percent; Alternatively PA 6 98-80%, PA 66 1-19% and PA 11 1-19%, preferably PA 6 98-90%, PA 66 9-1% and PA 11 9-1% Ternary copolyamide CoPA or mixed polyamide MPA, consisting of%.

The present invention also provides press felts or rod press felts, in particular felts suitable for paper making, made from the monofilaments of the above-mentioned compositions.

The above-described CoPA or MPA and auxiliary materials which are raw materials for monofilaments are known, for example, by methods known per se, typically at temperatures from 230 ° C. to 330 ° C. (see, eg, Handbuch der Kunststofftechnik II, C. Hauser Verlag, Munich 1986, pages 295-319 or German published patent application DE-OS 4336097) are melt extruded from the spinneret, cooled and further processed to produce a single filament. Conventional dressings, such as fatty acid salts or oils, can be applied externally on a single filament.

The new monofilaments and supporting fabrics made therefrom predominantly have improved lateral resilience (i.e. increased resistance to lateral mechanical loads compared to single filaments), abrasion resistance, flexural fatigue strength (alternate flexural loading of single filaments). Resistance), increased flexibility, greater residual strength of monofilament in the press felt after needle drilling, and better and more reliable processing characteristics when converting monofilament to industrial fabrics.

When the single filament according to the invention is used, the useful life of the industrial felt, in particular the compressed felt for the manufacture of paper and wood pulp, is extended compared to known crimped felts or industrial textiles.

Surprisingly, single filaments according to the invention, in particular single filaments made from CoPA of the above-mentioned composition, exhibit substantially greater lateral resilience and flexural fatigue strength than single filaments made from pure polyamides. Flexibility and lateral resilience are increased especially when the monofilaments contain 0.5-4% of oligomers considered to be caprolactam and extractable oligomers having up to 6 monomer units.

Support fabrics made from these monofilaments have also been unexpectedly found to have greater residual strength after needle puncture of the support fabric.

The increase in residual strength of the support fabric in the sewing zone after needle boring of the rod crimping felt is particularly advantageous compared to support fabrics made from known monofilaments.

Due to the greater lateral resilience, greater flexural fatigue strength, greater linear strength and greater flexibility, longer felt life or machine operation when operating a paper machine using the crimped felt or bar crimped felt according to the present invention. Time is achieved.

The lateral resilience of a single filament is measured by a so-called impact test. Because of this, a bundle of monofilaments collide at a rate of 2000 impacts per minute against a metal rod in a mechanical strength test apparatus. This lateral load on the axis of the single filament can be correlated broadly with the felt which is periodically exposed to pressure in the pressing section of the paper machine.

Flexural fatigue strength of a single filament is usually measured by a so-called flexural fatigue test.

The resistance of a single filament to alternating flexural loads is tested, for example, on a model 842 long-term flexural tester supplied by Frank. This tester has one stop clamp and one movable clamp. During the flexural test, the single filament is subjected to 10% fracture stress and flexes 2 x 90 ° 280 times per minute. The average number of bending operations performed on a single filament unit is counted until it is broken to determine the bending fatigue value.

The flexibility of a single filament is measured by its flexural stiffness. To measure the flexural stiffness, a single filament specimen (0.30 mm to 2.0 mm in diameter) is placed on two supports (separation distance A = 10 x diameter of a single filament) and when bent 0.2 times the diameter of a single filament The force F is measured, and the flexural stiffness S (in N * mm 2 units) of the following formula (1) or the standardized flexural stiffness Sn (N * mm 2) of the following formula (2) is calculated therefrom.

Is the average diameter of the single filament in mm; Φ _max is the maximum diameter of the single filament (mm); Φ _minimum is the minimum diameter of the single filament (mm); A is the distance between the supports (mm).

The copolyamides or polyamides mentioned in the raw material columns of Tables 1 to 3 were prepared by melt spinning on a monofilament spinning / take-off plant according to the method of German published patent application DE-OS 4336097.

In this method, a polymer melt of a specific polymer was spun through a spinneret and cooled in a water bath at about 20-30 ° C. The resulting monofilament was then taken up in hot water at about 85 ° C. followed by hot air and cured in hot air in the curing compartment.

The following polyamides or copolyamides were used:

1.polyamide 6 (PA 6),

2. copolyamides made from PA 6 and PA 66 containing 5% by weight PA 66 and 95% by weight PA 6 (CoPA 6.6 / 5), and

3. Copolyamides made from PA 6 and PA 66 containing 10% by weight of PA 66 and 90% by weight of PA 6 (CoPA 6.6 / 10).

Tables 1 to 3 below show the industrial data measured for the final monofilament. Table 1 below shows a single filament with a diameter of 0.4 mm (Examples 1 to 2). Table 2 below shows single filaments with a diameter of 0.5 mm (Examples 3 to 5). Table 3 below shows a single filament 0.2 mm in diameter (Examples 6-8).

Examples 1, 3, 4 and 6 show that the single filaments according to the invention obviously have lower flexural stiffness and therefore greater flexibility, greater flexural fatigue strength, and greater lateral resilience. They have less length loss than conventional PA 6 monofilaments in impact tests and have both greater knot strength and greater ring strength (see Comparative Examples 2, 5, 7 and 8).

The superiority of monofilaments according to the invention over known industrial monofilaments is evident from the measured mechanical properties.

The following terms are used in Tables 1-3:

Pullout factor: takeoff factor,

Hot air temperature: Hot air curing temperature (℃),

% Shrinkage: shrinkage of single filament during hot air curing

Linear density: the final linear density of a controlled single filament,

Adhesiveness:

Max Tensile Elongation: Max Tensile Elongation,

Knot: Knot Strength,

Collar: Collar Strength,

Hot air shrinkage: DIN 53866 pt. Hot air shrinkage according to 03 (150 ° C., 1 min),

Boiling shrinkage: DIN 53688 pt. Boiling shrinkage according to 02,

Flexural failure: recovery of alternative flexural loads, and

Stabilizers: hindered amines as stabilizers.

Claims (18)

a) 80 to 99% by weight of polyamide (PA) 6 and 1 to 20% by weight of at least one polyamide from the group consisting of PA 66, PA 12 and PA 11 or a mixture of fiber-forming copolyamides (CoPA) 100 to 96% by weight of polyamide (MPA), preferably 99.8 to 99% by weight, and b) monomers, oligomers for the sum of a) + b); Antioxidants, in particular sterically hindered phenols (SHP), aromatic amines or copper salts, especially salts of monovalent copper; Extrusion aids or molding release agents, in particular Ca, Mg or Zn salts of C ₁₀ -C ₂₂ fatty acids, particularly preferably Mg stearate, Ca stearate, Zn stearate; Nucleating agents, in particular talcum; And 0 to 4.0% by weight, preferably 0.02 to 4.0% by weight, of an auxiliary material selected in any desired combination from the group consisting of colorants, for example dyes and / or pigments. Industrial textile products, woven fabrics, knitted fabrics or felt fabrics, in particular conveyor belts, classified screen fabrics, screen printing screens, molded fabrics, crimped felts and bar felts, particularly preferably paper or wood pulp Use to make crimped felts for manufacturing or bar crimping felts. The process according to claim 1, wherein the copolyamide CoPA or mixed polyamide MPA is from 99 to 85% by weight of PA 6 and from 15 to 1% by weight of PA 66, preferably from 98 to 90% by weight of PA 6 and from 10 to 2% by weight of PA 66. , Particularly preferably from 97 to 93% by weight of PA 6 and from 7 to 3% by weight of PA 66. The process according to claim 1, wherein the copolyamide CoPA or mixed polyamide MPA is from 99 to 85% by weight of PA 6 and from 15 to 1% by weight of PA 12, preferably from 98 to 90% by weight of PA 6 and from 10 to 2% by weight of PA 12. , Particularly preferably from 97 to 93% by weight of PA 6 and from 7 to 3% by weight of PA 12. The process according to claim 1, wherein the copolyamide CoPA or mixed polyamide MPA is from 99 to 85% by weight of PA 6 and from 15 to 1% by weight of PA 11, preferably from 98 to 90% by weight of PA 6 and from 10 to 2% by weight of PA 11. , Especially preferably PA 6 98 to 93% by weight and PA 11 7 to 2% by weight. The process according to claim 1, wherein the copolyamide CoPA or mixed polyamide MPA is from 98 to 80% by weight of PA 6, from 1 to 19% by weight of PA 66 and from 1 to 19% by weight of PA 12, preferably from 98 to 90% by weight of PA 6 , PA 66 9 to 1% by weight and PA 12 9 to 1% by weight. The process according to claim 1, wherein the copolyamide CoPA or mixed polyamide MPA is from 98 to 80% by weight of PA 6, from 1 to 19% by weight of PA 66 and from 1 to 19% by weight of PA 11, preferably from 98 to 90% by weight of PA 6. , PA 66 9 to 1% by weight and PA 11 9 to 1% by weight. a) 80 to 99% by weight of polyamide (PA) 6 and 1 to 20% by weight of at least one polyamide from the group consisting of PA 66, PA 12 and PA 11 or a mixture of fiber-forming copolyamides (CoPA) 100 to 96% by weight of polyamide (MPA), preferably 99.8 to 99% by weight, and b) monomers, oligomers for the sum of a) + b); Antioxidants, in particular sterically hindered phenols (SHP), aromatic amines or copper salts, especially salts of monovalent copper; Extrusion aids or molding release agents, in particular Ca, Mg or Zn salts of C ₁₀ -C ₂₂ fatty acids, particularly preferably Mg stearate, Ca stearate, Zn stearate; Nucleating agents, in particular talcum; And 0 to 4.0% by weight, preferably 0.02 to 4.0% by weight, of an auxiliary material selected in any desired combination from the group consisting of colorants, for example dyes and / or pigments. Crimped felt or bar crimped felt, especially for papermaking, made substantially from a single filament consisting of: The process according to claim 7, wherein the copolyamide CoPA or mixed polyamide MPA is from 99 to 85% by weight of PA 6 and from 15 to 1% by weight of PA 66, preferably from 98 to 90% by weight of PA 6 and from 10 to 2% by weight of PA 66. , Particularly preferably, PA 6 97 to 93% by weight and PA 66 7 to 3% by weight. The process according to claim 7, wherein the copolyamide CoPA or mixed polyamide MPA is from 99 to 85% by weight of PA 6 and from 15 to 1% by weight of PA 12, preferably from 98 to 90% by weight of PA 6 and from 10 to 2% by weight of PA 12. , Particularly preferably, PA 6 97 to 93% by weight and PA 12 7 to 3% by weight. The process according to claim 7, wherein the copolyamide CoPA or mixed polyamide MPA is from 99 to 85% by weight of PA 6 and from 15 to 1% by weight of PA 11, preferably from 98 to 90% by weight of PA 6 and from 10 to 2% by weight of PA 11. , Particularly preferably, PA 6 98 to 93% by weight and PA 11 7 to 2% by weight. The process according to claim 7, wherein the copolyamide CoPA or mixed polyamide MPA is from 98 to 80% by weight of PA 6, from 1 to 19% by weight of PA 66 and from 1 to 19% by weight of PA 12, preferably from 98 to 90% by weight of PA 6 , PA 66 9 to 1% by weight and PA 12 9 to 1% by weight of the pressing felt or rod pressing felt. The process according to claim 7, wherein the copolyamide CoPA or mixed polyamide MPA is from 98 to 80% by weight of PA 6, from 1 to 19% by weight of PA 66 and from 1 to 19% by weight of PA 11, preferably from 98 to 90% by weight of PA 6. , PA 66 9 to 1% by weight and PA 11 9 to 1% by weight of the pressing felt or bar pressing felt. a) 80 to 99% by weight of polyamide (PA) 6 and 1 to 20% by weight of at least one polyamide from the group consisting of PA 66, PA 12 and PA 11 or a mixture of fiber-forming copolyamides (CoPA) 100 to 96% by weight of polyamide (MPA), preferably 99.8 to 99% by weight, and b) monomers, oligomers for the sum of a) + b); Antioxidants, in particular sterically hindered phenols (SHP), aromatic amines or copper salts, especially salts of monovalent copper; Extrusion aids or molding release agents, in particular Ca, Mg or Zn salts of C ₁₀ -C ₂₂ fatty acids, particularly preferably Mg stearate, Ca stearate, Zn stearate; Nucleating agents, in particular talcum; And 0 to 4.0% by weight, preferably 0.02 to 4.0% by weight, of an auxiliary material selected in any desired combination from the group consisting of colorants, for example dyes and / or pigments. A single filament consisting of 0.05 to 1 mm, in particular 0.1 to 0.8 mm, particularly preferably 0.2 to 0.5 mm in industrial monofilament. The process according to claim 13, wherein the copolyamide CoPA or mixed polyamide MPA is from 99 to 85% by weight of PA 6 and from 15 to 1% by weight of PA 66, preferably from 98 to 90% by weight of PA 6 and from 10 to 2% by weight of PA 66. , Particularly preferably from 97 to 93% by weight of PA 6 and from 7 to 3% by weight of PA 66. The process according to claim 13, wherein the copolyamide CoPA or mixed polyamide MPA is from 99 to 85% by weight of PA 6 and from 15 to 1% by weight of PA 12, preferably from 98 to 90% by weight of PA 6 and from 10 to 2% by weight of PA 12. And, particularly preferably, 97 to 93% by weight of PA 6 and 7 to 3% by weight of PA 12. The process according to claim 13, wherein the copolyamide CoPA or mixed polyamide MPA is from 99 to 85% by weight of PA 6 and from 15 to 1% by weight of PA 11, preferably from 98 to 90% by weight of PA 6 and from 10 to 2% by weight of PA 11. , Monofilaments characterized by copolyamide CoPA or mixed polyamide MPA, particularly preferably consisting of 98 to 93% by weight of PA 6 and 7 to 2% by weight of PA 11. The process according to claim 13, wherein the copolyamide CoPA or mixed polyamide MPA is from 98 to 80% by weight of PA 6, from 1 to 19% by weight of PA 66 and from 1 to 19% by weight of PA 12, preferably from 98 to 90% by weight of PA 6. , PA 66 9 to 1% by weight and PA 12 9 to 1% by weight of the single filament. The process according to claim 13, wherein the copolyamide CoPA or mixed polyamide MPA is from 98 to 80% by weight of PA 6, from 1 to 19% by weight of PA 66 and from 1 to 19% by weight of PA 11, preferably from 98 to 90% by weight of PA 6. , PA 66 9 to 1% by weight and PA 11 9 to 1% by weight of the single filament.