KR20180016595A - Process for the preparation of polyolefin fibers - Google Patents

Abstract

The present invention relates to a process for the production of polyolefin fibers having an average fiber diameter of less than 5000 nm, comprising the steps of: a) preparing a polyolefin solution in a solvent, b) forming a body And c) rotating the fiber manufacturing device, wherein rotation of the fiber manufacturing device is performed to produce a polyolefin fiber having an average fiber diameter of less than 5000 nm via the one or more openings passing said polyolefin solution, comprising the step of rotating the fiber production device, wherein the polyolefin is a polyethylene polymer having a weight average molecular weight (M _w) of at least 40,000 daltons and copolymers, and at least 120,000 The weight average of Dalton A polypropylene polymer having a self-weight (M _w ) and a copolymer; The fiber manufacturing device is rotated at a speed of at least 10,000 rpm (RPM). The invention also relates to said polyolefin fibers and to articles comprising said polyolefin fibers.

Description

[0001] PROCESS FOR THE PREPARATION OF POLYOLEFIN FIBERS [0002]

The present invention relates to a process for the production of polyolefin fibers, preferably nanofibres, in particular a process for the production of polyethylene fibers. The present invention also relates to the polyolefin fibers thus obtained.

There is a growing need for fiber webs made from very fine fibers and very fine fibers. This type of web is useful for the end use of selective barriers. Nanofiber webs are used in a wide range of applications such as filtration, membrane separation, protective military apparel, biosensors, wound dressings and tissue engineering scaffolds. However, despite the potential described above, the application of nanofibres was limited due to poor mechanical properties.

Electrospinning and melt-blown radiation is the most widely used spinning method for making polymer fibers. While electrospinning is preferred for nano-sized fibers, this technique presents several disadvantages, such as requirements for high-voltage magnetic fields, low production rates, and precise solution conductivity requirements.

Unlike electrospinning, force spinning does not require materials exhibiting dielectric properties for processing to define the materials that can be produced with the fibers. Force spinning is a method of spinning spinning at high speed. The centrifugal force and the hydrostatic pressure are combined to discharge the jet of the liquid material through the orifice. When the spray of material exits the orifice, the aerodynamic environment and the inertial force of the flame-retardant spinneret extrude the material into nanoscale fibers.

There is little or no success today in the production of polymeric nanofibers from polyolefins such as polyethylene and polypropylene, which have particularly good mechanical properties.

In view of the foregoing, there is a need to develop other efficient processes for the production of polyolefin fibers having improved mechanical properties and in particular polyolefin nanofibers.

The present invention provides a solution to one or more of the foregoing needs.

According to a first aspect of the present invention there is provided a process for the production of polyolefin fibers having an average fiber diameter of less than 5000 nm,

a) preparing a polyolefin solution in a solvent,

b) disposing the polyolefin solution in a fiber manufacturing device configured to receive the polyolefin solution and having a body including one or more openings, and

c) rotating the fiber manufacturing device, wherein rotation of the fiber manufacturing device is such that the polyolefin solution is passed through the one or more openings to produce a polyolefin fiber having an average fiber diameter of less than 5000 nm, Rotating the device

Lt; / RTI >

Wherein the polyolefin is selected from the group consisting of a polyethylene polymer and a copolymer having a weight average molecular weight (M _w ) of at least 40,000 daltons, and a polypropylene polymer and a copolymer having a weight average molecular weight (M _w ) of at least 120000 Daltons.

Preferably, a process for producing a polyolefin fiber having an average fiber diameter of less than 5000 nm is provided, said process comprising:

a) preparing a polyolefin solution in a solvent,

b) disposing the polyolefin solution in a fiber manufacturing device configured to receive the polyolefin solution and having a body including one or more openings, and

c) spinning the fiber manufacturing device, wherein rotation of the fiber manufacturing device is such that the polyolefin solution is passed through the one or more openings to produce a polyolefin fiber having an average fiber diameter of less than 5000 nm, Rotating the device

Lt; / RTI >

Wherein the polyolefin is selected from the group consisting of a polyethylene polymer and a copolymer having a weight average molecular weight (M _w ) of at least 40,000 daltons, and a polypropylene polymer and a copolymer having a weight average molecular weight (M _w ) of at least 120000 Daltons,

The fiber manufacturing device is rotated at a speed of at least 10,000 rpm (RPM).

In a second aspect, the present invention also comprises polyolefin fibers having an average fiber diameter of less than 5000 nm obtained by the process according to the first aspect of the present invention.

In a third aspect, the present invention is of comprising a polyolefin fiber having an average fiber diameter of less than 5000 nm, wherein the polyolefin is a polyethylene polymer having a weight average molecular weight (M _w) of at least 40,000 Daltons and copolymers, and at least 120,000 Daltons It is selected from the group consisting of polypropylene polymers and copolymers having a weight average molecular weight (M _w).

In a fourth aspect, the present invention also includes an article comprising a polyolefin fiber according to the second or third aspect of the invention, or a polyolefin fiber prepared according to the process according to the first aspect of the present invention.

Surprisingly, it has been found that the process of the present invention allows the production of polyolefin fibers having an average fiber diameter of less than 5000 nm and improved mechanical properties (tensile strength, modulus and viscosity).

The present invention will now be further described. In the following paragraphs, different aspects of the present invention are defined in more detail. Each aspect so defined may be combined with any other aspect or aspect, unless expressly stated to the contrary. In particular, any feature or statement presented as being preferred or advantageous may be combined with other features or statements presented as being advantageous or advantageous.

Figure 1 shows a schematic cross-sectional view of a fiber manufacturing device as used in Examples 1 and 2.

Before the processes, fibers, and articles of the present invention that are encompassed by the present invention are described, it should be understood that the present invention is not limited to the specific processes, fibers, and articles described and that such processes, fibers, do. It is also to be understood that the terminology used herein is not intended to be limiting, as the scope of the invention will be limited only by the appended claims.

Unless otherwise defined, all terms used to describe the invention, including technical and scientific terms, have the meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. By way of further guidance, definitions of terms used herein are included to better understand the teachings of the present invention. In describing the polymer resins, processes, articles and applications of the present invention, the terms used should be construed in accordance with the following definitions, unless the context otherwise requires.

As used herein, the singular forms "a", "an", and "the" include both singular and plural objects unless the context clearly dictates otherwise. By way of example, "resin" means one resin or one or more resins.

As used herein, the terms "comprise," "comprise," and "comprise" are synonymous with "including", "includes", or "having, And does not exclude additional elements, elements, or method steps that are not exhaustive. The terms "comprising," " comprising, "and" comprising "

An enumeration of a numerical range by an endpoint includes all integers and, preferably, fractions included within that range (e.g., 1 to 5, for example, 1, 2, 3 , 4, and may include, for example, 1.5, 2, 2.75 and 3.80 when representing a measurement). The enumeration of endpoints also includes the endpoint values themselves (e.g., 1.0 to 5.0 include both 1.0 and 5.0). Any numerical range recited herein is intended to include all subranges included therein.

Reference throughout this specification to "one embodiment" or "an embodiment " means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. Accordingly, the appearances of the phrase "one embodiment" or " embodiment "in various places throughout this specification are not necessarily all referring to the same embodiment, but may represent the same embodiment. In addition, certain features, structures, or characteristics may be, in one or more embodiments, coupled in any suitable manner as would be apparent to one of ordinary skill in the art from this disclosure. It is also to be understood that the embodiments described herein include some features included in other embodiments but not other features, and combinations of features of the different embodiments are within the scope of the invention as will be appreciated by those skilled in the art And also forms another embodiment. For example, in the claims and statements below, any of the embodiments may be used in any combination.

Preferred embodiments (features) and embodiments of the polymer resin, process, article, and application of the present invention are described below. Each of the statements and embodiments of the invention so defined may be combined with any other statements and / or embodiments, unless otherwise indicated. In particular, any feature presented as being preferred or advantageous may be combined with any other feature or statements presented as being advantageous or advantageous. In this regard, the present invention is particularly noticed with any of the following numbered aspects and any one or combination of any one or more of embodiments 1-22, along with any other statements and / or embodiments.

One. Process for the production of polyolefin fibers having an average fiber diameter of less than 5000 nm,

a) preparing a polyolefin solution in a solvent,

b) disposing the polyolefin solution in a fiber manufacturing device configured to receive the polyolefin solution and having a body including one or more openings, and

c) rotating the fiber manufacturing device, wherein rotation of the fiber manufacturing device is such that the polyolefin solution is passed through the one or more openings to produce a polyolefin fiber having an average fiber diameter of less than 5000 nm, Rotating the device

Lt; / RTI >

Wherein the polyolefin is selected from the group consisting of a polyethylene polymer and a copolymer having a weight average molecular weight (M _w ) of at least 40,000 daltons, and a polypropylene polymer and a copolymer having a weight average molecular weight (M _w ) of at least 120000 Daltons. Process for the production of polyolefin fibers.

2. Process for the production of polyolefin fibers having an average fiber diameter of less than 5000 nm,

a) preparing a polyolefin solution in a solvent,

b) disposing the polyolefin solution in a fiber manufacturing device configured to receive the polyolefin solution and having a body including one or more openings, and

c) rotating the fiber manufacturing device, wherein rotation of the fiber manufacturing device is such that the polyolefin solution is passed through the one or more openings to produce a polyolefin fiber having an average fiber diameter of less than 5000 nm, Rotating the device

Lt; / RTI >

Wherein the polyolefin is selected from the group consisting of a polyethylene polymer and a copolymer having a weight average molecular weight (M _w ) of at least 40,000 daltons, and a polypropylene polymer and a copolymer having a weight average molecular weight (M _w ) of at least 120000 Daltons,

Wherein the fiber manufacturing device is rotated at a speed of at least 10,000 revolutions per minute (RPM).

3. In statement 1 or statement 2, the fiber manufacturing device is rotated at a speed of at least 10,000 RPM, preferably at least 15,000 RPM, preferably at least 20,000 RPM, preferably at least 22,000 RPM.

4. A process according to any one of claims 1 to 3, wherein the polyolefin is selected from the group consisting of a polypropylene polymer and a copolymer having a weight average molecular weight (M _w ) of at least 120000 Daltons, and a polyethylene polymer and a copolymer , A process for the production of polyolefin fibers.

5. The polyolefin according to any one of claims 1 to 4, wherein the polyolefin has a molecular weight of at least 200,000 daltons, preferably at least 300,000 daltons, preferably at least 400,000 daltons, preferably at least 500,000 daltons, preferably at least 600,000 daltons, (M _w ) of at least 700 000 daltons, preferably at least 800 000 daltons, preferably at least 900 000 daltons, preferably at least 100 000 daltons, and a polypropylene polymer and a copolymer having a weight average molecular weight Lt; RTI ID = 0.0 > polyolefin < / RTI >

6. The process for producing polyolefin fibers according to any one of statements 1 to 5, wherein the polyethylene or polypropylene polymer used in the process of the present invention is a homopolymer.

7. A process for producing a polyolefin fiber according to any one of statements 1 to 6, wherein the polyethylene or polypropylene polymer is a linear polymer.

8. Wherein the polyethylene or polypropylene polymer has a molecular weight distribution of 10 or more in any one of statements 1 to 7.

9. Wherein the polyethylene or polypropylene polymer has a molecular weight distribution of 5 or more in any one of the statements 1 to 8. 8. A process for producing a polyolefin fiber,

10. Wherein the polyethylene or polypropylene polymer has a molecular weight distribution of 5 or more and 10 or less, preferably 6 or more and 10 or less, and more preferably 7 or more and 9 or less, in any one of statements 1 to 9. The polyolefin fiber according to any one of claims 1 to 9,

11. A process for producing a polyolefin fiber according to any one of statements 1 to 10, wherein the polyolefin is polyethylene.

12. A process for producing a polyolefin fiber according to any one of statements 1 to 11, wherein the polyolefin is ultra high molecular weight polyethylene (UHMWPE).

13. The process according to any one of statements 1 to 12, wherein the polyolefin fibers produced have an average fiber diameter of less than 2000 nm, preferably less than 1000 nm.

14. The process for producing a polyolefin fiber according to any one of the first to seventh aspects of the present invention, further comprising heating the fiber manufacturing device at a temperature of preferably at least 40 캜, more preferably at least 100 캜 and at most 200 캜. .

15. The process according to any one of statements 1 to 14, further comprising cooling the fibers.

16. The process according to any one of claims 1 to 15, further comprising collecting fibers on a collector to form a fibrous web.

17. The process according to any one of claims 1 to 16, further comprising removing solvent from the fibers.

18. In any one of statements 1 to 17, the polyolefin solution contains a polyolefin in an amount of 1 wt% or more and 50 wt% or less, preferably 5 wt% or more and 20 wt% or less, based on the total weight of the polyolefin solution. Fabrication process of fibers.

19. Wherein the solvent is selected from the group consisting of C6-C16 alcohols, fully saturated white mineral oils, vegetable oils, C4-C20 carboxylic acids, aliphatic and alicyclic hydrocarbons, petroleum fractions, mineral oils, kerosene, Wherein the polyolefin is selected from the group consisting of aromatic hydrocarbons, halogenated hydrocarbons, cycloalkanes, cycloalkenes, and terpenes containing hydrogenated derivatives thereof.

20. In any of statements 1 to 19, the at least one opening has at least one diameter of at least 2 mm, preferably at least 1 mm, preferably at least 0.5 mm, preferably at least 0.1 mm, of polyolefin fibers Manufacturing process.

21. A polyolefin fiber having an average fiber diameter of less than 5000 nm obtained by a process for producing a polyolefin fiber according to any one of statements 1 to 20.

22. As a polyolefin fiber having an average fiber diameter of less than 5000 nm, wherein the polyolefin is at least 40,000 daltons in weight average molecular weight (M _w) with a polyethylene polymer and the copolymer, and the weight average molecular weight of at least 120,000 Daltons (M _w) Lt; RTI ID = 0.0 > polypropylene < / RTI > polymer and a copolymer.

23. In the statement 21, the polyolefin fibers have an average fiber diameter of 5000 nm, wherein the polyolefin is a weight average molecular weight of at least 40,000 Daltons (M _w) with a polyethylene polymer and the copolymer, and the weight average molecular weight of at least 120,000 Daltons ( 0.0 &_gt; Mw) &_lt; / RTI &_gt; and a copolymer.

24. 21. The polyolefin fiber according to any one of claims 21 to 23, which is in the form of a non-woven web.

25. 21. The polyolefin fiber according to any one of claims 21 to 24, wherein the polyethylene or polypropylene polymer is a homopolymer.

26. 21. The polyolefin fiber according to any one of claims 21 to 25, wherein the polyethylene or polypropylene polymer is a linear polymer.

27. 21. The polyolefin fiber according to any one of claims 21 to 26, wherein the polyethylene or polypropylene polymer has a molecular weight distribution of 10 or less.

28. 21. The polyolefin fiber according to any one of claims 21 to 27, wherein the polyethylene or polypropylene polymer has a molecular weight distribution of 5 or more.

29. In any of statements 21 to 28, the polyethylene or polypropylene polymer has a molecular weight distribution of 5 or more and 10 or less, preferably 6 or more and 10 or less, preferably 7 or more and 9 or less.

30. 21. The polyolefin fiber according to any one of claims 21 to 29, wherein the polyolefin is polyethylene.

31. 21. The polyolefin fiber according to any one of claims 21 to 30, wherein the polyolefin is UHMWPE.

32. An article comprising a polyolefin fiber according to any one of statements 21 to 31, or a polyolefin fiber produced according to a process according to any one of statements 1 to 20.

As used herein, the term "fiber" means a generally elongated structure having a defined length or substantially substantially continuous.

The term "nanofiber" as used herein means fibers having a number average diameter (or similar cross-sectional dimension to a non-circular shape) of less than about 1000 nm. In the case of non-circular cross-section nanofibers, the term "diameter " as used herein means the largest dimension.

The present invention uses a fiber forming device that utilizes a centrifugal spinning technique (referred to herein as force spinning technique).

The processes and equipment for power radiation are not only known by a number of well known techniques, but also by the United States of America, Texas, McAllen, Inc. (see http://fiberiotech.com/products/forcespinning-products/) And are known to those skilled in the art by commercial equipment suppliers such as FibeRio® Technology Corporation. Therefore, a detailed description of the force radiation is not necessary, and only a brief description will be provided herein.

The fibers are formed by a process comprising the release of a polyolefin solution from a fiber forming device comprising a body (e. G., Spinneret or spin disc) that propels the polymer solution in the form of fibers by centrifugal force. The polyolefin fibers may be produced using the force emulsion of the polyolefin solution through one or more openings provided in the body.

According to the present invention, the process of the present invention comprises:

a) preparing a polyolefin solution in a solvent,

b) disposing the polyolefin solution in a fiber manufacturing device configured to receive the polyolefin solution and having a body including one or more openings, and

c) rotating the fiber manufacturing device, wherein rotation of the fiber manufacturing device is such that the polyolefin solution is passed through the one or more openings to produce a polyolefin fiber having an average fiber diameter of less than 5000 nm, Rotating the device

Lt; / RTI >

Wherein the polyolefin is selected from the group consisting of a polyethylene polymer and a copolymer having a weight average molecular weight (M _w ) of at least 40,000 daltons, and a polypropylene polymer and a copolymer having a weight average molecular weight (M _w ) of at least 120000 Daltons. Preferably the fiber manufacturing device is rotated at a speed of at least 10,000 RPM.

Polyethylene suitable for use in the present invention may be one or more copolymers having a random ethylene homopolymer or a weight average molecular weight (M _w) of any of the ethylene copolymers and at least 40 000 Daltons. The copolymer is different from ethylene and is selected to be suitable for copolymerization with olefins. Copolymers include but are not limited to C3-C20 alpha-olefins such as propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl- , 1-hexadecene, 1-octadecene or 1-eicosene. In a preferred embodiment, the polyethylene is a homopolymer.

For example, the polyethylene polymer and copolymer for use in the present invention may have a maximum of 34 g / 10 min as measured in accordance with ISO 1133 procedure B, condition D, at a temperature of 190 캜 and a load of 2.16 kg, A melt flow index of 30 g / 10 min, preferably of at most 20 g / 10 min, preferably of at most 10 g / 10 min, preferably of at most 1 g / 10 min and preferably of at most 0.1 g / MI2).

The polyethylene polymer and the copolymer for use in the present invention may be produced by polymerizing one or more copolymers such as ethylene and optionally ethylene in the presence of a catalyst system and optionally in the presence of hydrogen. As used herein, the term "catalyst" means a material that causes a change in the rate of polymerisation reaction. In the present invention, it is particularly applicable to a catalyst suitable for the polymerization of propylene to polypropylene. In some embodiments, the catalyst may be a chromium, chitaglata or a metallocene catalyst system. In a preferred embodiment, the catalyst is a Chigler-Natta catalyst.

Preferably, the polyethylene polymer used herein is a homopolymer, preferably a homopolymer having a low long chain branching content.

Preferably, the polyethylene is an ultra high molecular weight polyethylene (UHMWPE) having a molecular weight distribution of 10 or less; Preferably the UHMWPE has a molecular weight distribution of 5 or more; Preferably the UHMWPE has a molecular weight distribution from 5 to 10; Preferably the UHMWPE has a molecular weight distribution from 5 to 9; UHMWPE has a molecular weight distribution of 6 or more and 9 or less.

Polypropylene suitable for use in the present invention may be any propylene homopolymer or copolymer of any propylene and at least one copolymer having a weight average molecular weight (M _w ) of at least 120000 Daltons.

The polypropylene may be a random copolymer. The one or more copolymers are preferably selected from the group consisting of ethylene and C4-C10 alpha-olefins such as 1-butene, 1-pentene, 1-hexene, 1-octene, or 4-methyl-1-pentene. Ethylene and 1-butene are preferred copolymers. Ethylene is the most preferred copolymer. The polypropylene may be a propylene homopolymer.

For example, the polypropylene polymer and copolymer have a maximum of 32 g / 10 min., For example up to 30 g / 10 min., Measured according to ISO 1133, condition M, at 230 DEG C and a load of 2.16 kg, A melt flow index of up to 20 g / 10 min, preferably up to 10 g / 10 min, preferably up to 1 g / 10 min, preferably up to 0.1 g / 10 min.

Polypropylene polymers and copolymers for use in the present invention can be produced by polymerizing propylene and optionally one or more copolymers such as ethylene in the presence of a catalyst system and optionally in the presence of hydrogen. In some embodiments, the catalyst may be a chromium, chitaglata or metallocene catalyst system.

Preferably, the polyethylene or polypropylene polymer used in the present invention has an ultrahigh molecular weight (UHMW), i. E. At least 5 dl as measured for an aqueous solution of decalin (decahydronaphthalene) at 135 DEG C in accordance with ISO 1628-3 / g, preferably at least 10 dl / g, more preferably at least 15 dl / g. Preferably, IV is at most 40 dl / g, more preferably at most 30 dl / g.

The UHMW polyolefin solution is preferably prepared at a concentration of at least 1% by weight. The UHMW polyolefin solution preferably has a concentration of at most 50 wt.%, More preferably at most 30 wt.%, Even more preferably at most 25 wt.%, Most preferably at most 20 wt.%.

To prepare the polyolefin solution (or gel), any known solvent suitable for forming the polyolefin gel may be used. In some embodiments, the solvent is selected from the group consisting of C6-C16 alcohol; Fully saturated white mineral oil; Vegetable oils such as olive oil, peanut oil, palm oil, and coconut oil; C 4 -C 20 carboxylic acids such as butanoic, pentanoic, hexanoic, heptanoic, octanoic, nonanoic, decanoic, undecanoic, dodecanoic, tridecanoic, tetradecanoic, pentadecanoic, hexadecanoic , Heptadecanoic acid, octadecanoic acid, nonadecanoic acid, and eicosanoic acid; Aliphatic and alicyclic hydrocarbons and isomers thereof selected from the group consisting of aliphatic and alicyclic hydrocarbons such as octane, nonane, decane and paraffins; Petroleum fractions; Mineral oil; Kerosene; Aromatic hydrocarbons such as aromatic hydrocarbons selected from the group comprising toluene, xylene and naphthalene, and hydrogenated derivatives thereof such as decalin and traline; Halogenated hydrocarbons such as monochlorobenzene; Cycloalkanes such as methylcyclopentane; Cycloalkene; And terpenes such as camphene, p-menthane-3,8-diol, limonene and dipentene. In addition, combinations of the above-mentioned solvents may be used, and the combination of solvents is referred to as a solvent for simplification.

(CAS 628-99-9), C9-C11 alcohols such as (CAS 66455-17-2) or C10-16 < RTI ID = 0.0 > Alcohols such as (CAS 67762-41-8).

Preferably, when analyzing the solution (gel) by DSC compared to the analysis of pure polymer, the crystallization temperature should be reduced by at least 1 占 폚. In order to determine this crystallization temperature reduction, the following procedure is used:

After calibrating the temperature using an indium sample (see, for example, thermal analysis of polymers, fundamentals and applications , edited by JD Menczel and RB Prime, John Wiley & Sons, Hoboken, New Jersey To 10 mg) is introduced into a DSC apparatus (e.g., DSC1 from Mettler Toledo). The following thermal history is applied: stabilization of the sample for 4 minutes at 20 ° C, heating to 220 ° C at 20 ° C / min, stabilization for 3 minutes at 220 ° C, Cooling, stabilization of the sample at 20 ° C for 3 minutes, and heating at 20 ° C / min to 220 ° C. The crystallization temperature is determined during the cooling step described above. After subtracting the baseline (the line drawn between the starting point of the crystallization peak, which is somewhat close to 130 캜 and 20 캜), the crystallization temperature is assimilated to the extreme temperature of the peak;

- The above procedure is repeated with gel. The difference in the crystallization temperature of one of the pure polymer and the polymer in the solution (gel) can thus be calculated.

Step b) of the process of the present invention comprises placing the polyolefin solution in a fiber manufacturing device configured to receive the polyolefin solution and having a body comprising one or more openings, wherein step c) Wherein rotation of the fiber manufacturing device passes the polyolefin solution through one or more openings to produce a polyolefin fiber having an average fiber diameter of less than 5000 nm.

In some embodiments, the fiber forming device can include a spinnerette having a reservoir configured to contain a polyolefin solution. During operation, the spinnerette is rotated centrifugally about the shaft at high revolutions per minute to form hydrostatic and centrifugal forces. As the spinnerette is rotated, hydrostatic and centrifugal forces push the solution out into an outer wall having at least one opening (orifice) located therein. The polyolefin solution enters and exits the one or more openings. Centrifugal and hydrostatic pressures are combined to initiate the injection of a solution that affects the fiber collector to produce the fibers.

During rotation, the polyolefin solution is released as an injection of material from one or more openings (orifices) into the ambient atmosphere. And may be sized and configured to cause micro-injection of one or more openings and associated channel feed solution to be formed at the outlet from the openings. As used herein, an aperture means an exit orifice and any associated channels or passages that serve to define the characteristics of the ejection of the fiber-forming solution as well as to the aperture. These openings may have various shapes (e.g., circular, oval, rectangular, square) and various diameters. When multiple openings are used, not all openings need to be the same as the other openings, but in certain embodiments all openings have the same configuration. Preferably, each opening has a diameter of at most 2 mm, preferably at most 1 mm, even more preferably at most 0.5 mm, for example at most 0.1 mm. The diameter of the openings herein means the effective diameter, that is, for openings of non-circular or irregular shape, it means the maximum distance between the outer edges of the openings.

The discharged material can be solidified as a microfine fiber having a diameter considerably smaller than the inner diameter of the outlet port.

The fiber manufacturing device may rotate, for example, at a speed of at least 10,000 rotations per minute (RPM), and in some embodiments, it is at least 15,000 RPM. In other embodiments, it is at least 20,000 RPM. In other embodiments, it is at least 22000 RPM. The speed of the fiber manufacturing device may be fixed while the fiber manufacturing device is emitting, or it may be adjusted while the fiber manufacturing device is emitting.

If desired, the temperature of the rotating body may also be controlled during fiber spinning. For example, the rotational body temperature may be in the range of about 40 캜, preferably about 100 캜 to about 200 캜.

During centrifugal spinning, the fibers are radially dispersed from the rotating member toward the collecting surface. As used herein, "collection" of fibers refers to fibers that become dormant to the fiber collection device or collector. After the fibers have been collected, the fibers may be removed from the fiber collection device by man, robot, or conveyor belt by gravity or other techniques. Various methods and fiber (e.g., nanofiber) collecting devices may be used to collect the fibers.

For example, the fibers may be discharged from the spinnerette toward a surface disposed below the spinnerette or to a wall opposite the outlet port on the spinnerette. The collection surface can be as varied as desired, and can also be fixed or rotated during collection of the fibers. In one embodiment, for example, the collection surface may be provided on a collection wall surrounding the rotating member.

The collected fiber material may be processed into webs of two- or three-dimensional entangled fibers that can be processed to the desired surface area and thickness and controlled over the surface area of the collector, depending on the amount of time the fibers are continuously discharged toward the collector Can be formed.

Preferably, the polyolefin fibers are then cooled. In some embodiments, the temperature at which the polyolefin fibers are cooled is at most 100 占 폚, more preferably at most 80 占 폚, and most preferably at most 60 占 폚. Preferably, the temperature at which the polyolefin fibers are cooled is at least 1 占 폚, more preferably at least 5 占 폚, even more preferably at least 10 占 폚, and most preferably at least 15 占 폚.

Regardless of the particular technique employed, the solvent may be removed from the fibers during and / or after spinning. The fibers (or the web containing the fibers) may simply be washed, dried and / or heated to remove the solvent. Therefore, the solvent may be removed by evaporation, washing or any other techniques.

After forming the polyolefin fibers, the polyolefin fibers may undergo a solvent removal step in which the solvent is at least partially removed from the polyolefin fibers to form solid polyolefin fibers.

The solvent removal process may be carried out by known methods, for example, by evaporation when a relatively volatile solvent, such as decalin, is used to make the polyolefin solution, or by using an extract such as cyclohexane, for example when mineral oil is used, May be performed by a combination of the above methods. Suitable extracts are solvent dependent. Preferably, the extract is selected from the group consisting of cyclohexane, ethanol, ether, acetone, cyclohexanone, 2-methylpentanone, n-hexane, dichloromethane, trichlorotrifluoroethane, diethyl ether and dioxane, Are those fluids that do not undergo significant changes to the polyolefin network structure of the same polyolefin gel fibers. Preferably, the extract is selected so that the solvent is separated from the extract for recycling.

In a preferred embodiment, the residual solvent remaining in the polyolefin fibers of the present invention is preferably removed by placing the fibers in a vacuum oven at a temperature of preferably at most 148 ° C, more preferably at most 145 ° C, most preferably at most 135 ° C do. Preferably, the oven is maintained at a temperature of at least 20 캜, more preferably at least 50 캜. More specifically, removal of the residual solvent is carried out while keeping the fibers tight, i.e., preventing the fibers from loosening.

The amount of residual solvent remaining in the solid polyolefin fibers after the extraction step may vary within a large range, but the smallest amount of residual solvent is preferred. Preferably, the residual solvent is at most 15 mass%, more preferably at most 10 mass%, most preferably at most 5 mass%, even more preferably at most 1 mass% of the amount of the initial solvent in the polyolefin solution. Preferably, the polyolefin fibers at the end of the solvent removal step comprise a solvent in an amount less than 800 mass ppm. More preferably, the amount of the solvent is less than 600 mass ppm, even more preferably less than 300 mass ppm, and most preferably less than 100 mass ppm.

With respect to the fibers being collected, in certain embodiments, at least some of the fibers collected are continuous, discontinuous, matte, woven, nonwoven, or a combination of such configurations. The fibers may be formed of a two- or three-dimensional web, i.e., a mat, a film, or a membrane.

The fibers produced using any of the devices and methods described herein may be used in a variety of applications. Some common areas of use are: food, materials, electricity, defense, tissue engineering, biotechnology, medical equipment, energy, alternative energy (eg solar, wind, nuclear and hydro energy), therapeutic drugs, drug delivery Water, fuel, semiconductor, biomedical, etc.), automotive, sports, aviation, space, energy transfer, paper, substrate, sanitary, But are not limited to, cosmetics, construction, clothing, packaging, geotextile, thermal and acoustic insulation.

Some products that may be formed using polyolefin fibers include: filters; Wound dressing; A cell growth substrate or scaffold; Battery separator; Seal material; Chemical sensors; Water & stain resistant fibers / fabric, smear resistance, insulation, self-cleaning, penetration resistance, antibacterial, porosity / breathing, tear resistance, and abrasion resistance; Personal body protection armor energy absorption; Building reinforcement; Tissue engineering substrate; Tissue Engineering Petri dish; Filters used in pharmaceutical manufacturing; A filter for the dip filter function; Hydrophobic materials such as fabrics; Building products that enhance durability, airtightness; glue; tape; Epoxy; pool; Absorbent material; Diapermedia; mattress cover; Acoustic material; And liquid, gas, chemical or air filters.

The process of the present invention has the advantage of not having the general disadvantages of electrospinning. For example, since the polarity aspect of the gel is not necessarily required, there are few restrictions on the solvent used. A polyolefin fiber having an average fiber diameter of 5000 nm is obtained.

Examples of mechanical properties constructed in consideration of the present invention are tensile strength, elastic modulus, breaking strength, elongation at break, and the like.

The following examples serve to illustrate the invention only and should not be construed as limiting the scope of the invention in any way. Although the present invention is shown only as a part of these forms, it will be apparent to those skilled in the art that the present invention is not limited thereto, but can be variously modified and modified without departing from the scope of the present invention.

Example

Test method

In the foregoing detailed description and in the following non-limiting examples, the following test methods were used to determine various reported characteristics and characteristics.

(M _n (number average molecular weight), M _w (weight average molecular weight), M _z (z average molecular weight)), except for polymers showing extremely high mass and therefore solubility problems (such as UHMWPE) (SEC), in particular by gel permeation chromatography (GPC). Briefly, GPC-IR5 from Polymer Char is used: 10 mg of a polyethylene sample is dissolved in 10 ml of trichlorobenzene at 160 ° C for 1 hour. Injection amount: about 400,, automatic sample preparation and injection temperature: 160 캜. Column temperature: 145 占 폚. Detector temperature: 160 ° C. Two Shodex AT-806MS (Showa Denko) and one Styragel HT6E (Waters) columns are used at a flow rate of 1 ml / min. Detector: Infrared detector (2800 ~ 3000 cm ^-1 ). Calibration: a narrow standard of polystyrene (PS) (commercially available). Calculation of the molecular weight of each fraction (i) of the eluted polyethylene (M _i) has Mark-Houwink relation _{(log 10 (M PE) =} 0.965909 × log 10 (M PS) - 0.28264) ( terminated low molecular weight in the M _PE = 1000 Lt; / RTI >

The average molecular weight is used to establish the molecular / property relationships is the number average (M _n), weight average (M _w) and z-average (M _z) molecular weight. These averages are defined by the following equation and are determined from the calculated M _j :

Here, N _i and W _i are the number and weight of molecules each having a molecular weight (Mi). In each case the third term (rightmost) defines how to obtain this average from the SEC chromatogram. Where h _i is the height of the SEC curve (from the baseline) at the i-th elution fraction, and M _i is the molecular weight of the species eluting at this increment.

The molecular weight distribution of UHMWPE is measured. For UHMWPE, the molecular weight distribution was determined from the quantification of the transition zone between Newtonian viscosity and the exponential domain. Such transitions are known to be related to both long chain branching content and molecular weight distribution of the polymer. Since the long chain branching content of the polyethylene grades used in the example (UHMWPE GUR® 4113) is zero or at least very low, such transitions can be associated with molecular weight distributions.

- The rheological measurements were carried out at 230 ° C with a strain of 0.5% (to remain in the linear viscoelastic domain) at frequencies (ω) in the range between 0.05 and 50 rad / s (three frequencies were analyzed for frequency decay) Was made in ARES equipment (manufactured by Instrument);

- As soon as the temperature (230 DEG C) was reached, it took about 3 hours of stabilization time before starting the measurement (due to the very long required stabilization time when preparing polymer discs used in ARES equipment, 5000 ppm Irganox B215 Were premixed in UHMWPE fluff).

The rheological data were then fitted using the Carreau-Yasuda equation (see below). In this equation, "n" is "0 ",and" a "is a parameter for quantifying the transition region between the Newtonian viscosity and the exponential domain. The higher the "a" is, the narrower the relaxation spectrum (thus, the molecular weight distribution becomes narrower if the long chain branch is no longer present in the polymer).

- The parameters fitted to the UHMWPE GUR® 4113 are:

? ₀ = 3.52 * 10 ^ 9 Pa * s

? = 2629 s

a = 0.166

to be.

For the UHMW polyethylene, the molecular weight of decalin unique in 135 ℃ viscosity (IV - unit: dl / g) was determined by the measurement of which Margolies equation: viscosity through Mv (kdalton) = 53.7 * ( IV) 1.49 molecular weight average (Mv).

Measurement of fiber diameter was performed using optical microscopy when the fiber diameter was greater than 4 탆, and for smaller diameters, scanning electron microscope (SEM) method was used;

- Optical microscope determination of fiber diameter: Five fiber segments were fixed in flat glass and introduced into a Leica DMLP microscope connected to a JVC camera. A "x40" lens was used. The images of the five fibers were then registered and analyzed using IM500 software from Leica: fiber diameters were determined by comparison with reference images (images of certified graduated glasses previously recorded using the same lens). The reported diameters were the average of the five determinations.

- For SEM microscopy measurements, a small bundle containing several fibers was introduced vertically into the capsule and embedded within the epoxy resin. After 24 hours of curing of the resin, the bundle + epoxy samples were cut in a direction across the fiber axis (using a diamond-mounted milling machine). By doing so, a carbon treated (metallized) surface was available. SEM images were taken from retrodiffused electrons, which provide chemical contrast between the fibers and the resin used in the built-in procedure. The measurements were then performed using image processing software. References for SEM measurements: "Prion des echantillons pour MEB et Microanalyse" - Philippe Jonnard (GNMEBA) - EDP Sciences and "Polymer Microscopy" - Linda C. Sawyer, David T. Grubb and Gregory F. Meyers - Ed. Chaoman and Hall.

Used equipment

1 shows a schematic cross-sectional view of a fiber manufacturing device as used in Example 1 and Example 2. Fig. The fiber manufacturing device includes a spinneret (1). The spinneret 1 is mechanically coupled to a motor 2 that rotates the spinneret 1 through a shaft 5 in a circular motion. The speed of the motor 2 is adjustable by 2000 RPM increments from 10000 to 22000 RPM. The motor 2 was fixed to the rigid frame 3 and a circular collector 4 of 56 cm diameter was centered from the axis of the spinneret 1. The spinning nozzle (1) contained a stainless steel cell (7) closed with a screwed lead (6). At the bottom of the cell 7, the two opposing orifices were fitted with screws with a calibration bore 8 of 0.5 mm diameter. The shaft 5 is screwed onto the top of the lid 6 so as to be attached to the mandrel of the motor 2. The external dimensions of the cell 7 were 29.96 mm diameter and 35.40 mm height. The internal dimensions of the cell 7 were 20.80 mm diameter and 11.13 mm height.

Example  One

0.52 g of UHMWPE (marketed by Ticona under the trade designation GUR® 4113; linear polyethylene in powder form, molecular weight calculated using the Margolies formula (Mv (kdalton) = 53.7 IV ^{1 .49} ) of approximately 3.9 MM g / mol, An intrinsic viscosity (IV in dl / g) of about 17.90 dl / g as measured in accordance with ISO 1628-3, and a molecular weight distribution in the range of 7 to 9, measured as described above, It was mixed with this. The mixture was placed in an oven at < RTI ID = 0.0 > 180 C < / RTI > The gel gradually formed.

Once a uniform gel was formed, a portion of the hot gel was quickly placed into the fiber manufacturing device as described above and as shown in FIG. Then, the rotation of the spinnerette was imposed at 16000 RPM. The fibers were then collected on a collector (4).

The average measured diameter of the resulting fibers was 3.5 [mu] m.

Example  2

Although the procedure described in Example 1 was reproduced, the rotational speed imposed on the spinnerette was 22,000 RPM. The average measured diameter of the resulting fibers was 0.9 탆.

Claims (14)

Process for the production of polyolefin fibers having an average fiber diameter of less than 5000 nm,
a) preparing a polyolefin solution in a solvent,
b) disposing the polyolefin solution in a fiber manufacturing device configured to receive the polyolefin solution and having a body including one or more openings, and
c) spinning the fiber manufacturing device, wherein rotation of the fiber manufacturing device is such that the polyolefin solution is passed through the one or more openings to produce a polyolefin fiber having an average fiber diameter of less than 5000 nm, Rotating the device
Lt; / RTI >
Wherein the polyolefin is selected from the group consisting of a polyethylene polymer and a copolymer having a weight average molecular weight (M _w ) of at least 40,000 daltons, and a polypropylene polymer and a copolymer having a weight average molecular weight (M _w ) of at least 120000 Daltons,
Wherein the fiber manufacturing device is rotated at a speed of at least 10,000 revolutions per minute (RPM). The method according to claim 1,
Wherein the polyolefin is selected from the group consisting of a polypropylene polymer and a copolymer having a weight average molecular weight (M _w ) of at least 120000 Daltons, and a polyethylene polymer and a copolymer. 3. The method according to claim 1 or 2,
Wherein the polyolefin fibers produced have an average fiber diameter of less than 2000 nm. 4. The method according to any one of claims 1 to 3,
Wherein the polyolefin solution comprises from 1 wt% to 50 wt%, preferably from 5 wt% to 20 wt%, of polyolefins based on the total weight of the polyolefin solution. 5. The method according to any one of claims 1 to 4,
Wherein the solvent is selected from the group consisting of C6-C16 alcohols, fully saturated white mineral oils, vegetable oils, C4-C20 carboxylic acids, aliphatic and alicyclic hydrocarbons, petroleum fractions, mineral oils, kerosene, aromatic hydrocarbons and hydrogenated derivatives thereof, halogenated hydrocarbons, Cycloalkane, cycloalkene, and terpene. ≪ Desc / Clms Page number 24 > 6. The method according to any one of claims 1 to 5,
Wherein said at least one opening has at least one diameter of at least 2 mm, preferably at least 1 mm, preferably at least 0.5 mm, preferably at least 0.1 mm. 7. The method according to any one of claims 1 to 6,
Wherein the polyolefin is polyethylene. 8. The method according to any one of claims 1 to 7,
Wherein the polyolefin is UHMWPE. A polyolefin fiber having an average fiber diameter of less than 5000 nm obtained by a process for producing a polyolefin fiber according to any one of claims 1 to 8. 10. The method of claim 9,
The polyolefin fibers have an average fiber diameter of less than 5000 nm, wherein the polyolefin has at least 40 000 daltons, a weight average molecular weight (M _w) of having polyethylene polymers and copolymers, and the weight average molecular weight of at least 120,000 Daltons (M _w) Polypropylene polymers, and copolymers. 11. The method according to claim 9 or 10,
A polyolefin fiber, in the form of a nonwoven web. 12. The method according to any one of claims 9 to 11,
Wherein the polyolefin is polyethylene. 13. The method according to any one of claims 9 to 12,
Wherein the polyolefin is UHMWPE. An article comprising a polyolefin fiber according to any one of claims 9 to 13 or a polyolefin fiber prepared according to a process for the production of a polyolefin fiber according to any one of claims 1 to 8.

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